article_name	topic_id	topic_keywords	abstract
10.1002-adem.200320508	-1		By using electromagnetic levitation, liquid Cu-Co alloys can be under cooled below their liquidus temperature into the metastable miscibility gap, leading to a phase separation into a cobalt-rich L-1 phase and a cobalt-poor L-2 phase. This paper reports on experimental and theoretical investigations into the properties of this system, including equilibrium shape, surface, and interfacial tension, phase separation, as well as solidification behavior. Solidification experiments were performed in microgravity in order to minimize the effect of convection on the resulting microstructure.
10.1002-adem.200700128	11	glass; bulk; metallic; bulk metallic; gfa; bmg; glassy; metallic glass; ability; bulk metallic glass; amorphous; addition; crystallization; mm; glass-forming	The mechanical behavior of the work-hardening Cu(47.5)Zr(47.5)Al(5) bulk-metallic glass in compression was investigated and compared with that of Zr(55)Ni(5)Al(10)Cu(30) bulk-metallic glass. Two glassy alloys exhibit substantially different plastic-flow behaviors and shear-band patterns. Cu(47.5)Zr(47.5)Al(5) displays much smaller inhomogeneity of the plastic deformation both in time and in space than Zr(55)Ni(5)Al(10)Cu(30). The work-hardening capability of Cu(47.5)Zr(47.5)Al(5) may originate from deformation-induced nanocrystallization that may strengthen effectively a shear band.
10.1002-adem.201000033	-1		High-pressure torsion (HPT) was conducted on Cu alloys containing ferromagnetic Co and Fe particles. Electron probe microanalysis, X-ray diffraction analysis, and transmission electron microscopy confirmed that the particles were significantly refined through fragmentation and some fractions were dissolved into the Cu matrix with straining by HPT. Saturation magnetization decreases with straining and coercive force increases with straining but they level off after intense straining. Magnetoresistance with an isotropic feature corresponding to giant magnetoresistance (GMR) appears at room temperature by processing with HPT. It is demonstrated that PT is a potential process for controlling magnetic properties such as saturation magnetization and coercive force and also for creating GMR in the alloys prepared by conventional ingot metallurgy.
10.1002-adem.201000169	11	glass; bulk; metallic; bulk metallic; gfa; bmg; glassy; metallic glass; ability; bulk metallic glass; amorphous; addition; crystallization; mm; glass-forming	The microstructure and mechanical properties of Cu46.5Zr48.5Al5 and Cu50Zr50 rods are investigated. Cu50Zr50 is composed of nanostructured martensitic phases, while the Cu46.5Zr48.5Al5 alloy comprises micrometer-sized dendrites (mainly austenitic phase) in an amorphous matrix. Both samples show considerable plasticity under compression and a work-hardening ability. Martensitic phase transformations during deformation play a significant role with regard to the mechanical properties. Nanoindentation tests on the different phases comprising the alloys indicate that the amorphous matrix in Cu46.5Zr48.5Al5 is harder than the crystalline phases and has a less-pronounced indentation-size effect.
10.1002-adem.201100080	6	grain; deformation; strain; strength; dislocation; cu-; tensile; size; ecap; grain size; sfe; ductility; hardening; high; stress	Pure Cu was processed by ECAP at five different temperatures from room temperature (RT) to 523 K. The influence of pressing temperature on microstructure evolution and tensile behavior was investigated in detail. The results show that as the ECAP temperature is increased the grain size and ductility both increase whereas the dislocation density and yield strength decrease. In the case of ECAP processing in the range of RT to 473 K the mechanism governing microstructural refinement is continuous dynamic recrystallization (CDRX), whereas at 523 K the mechanism changes to discontinuous dynamic recrystallization (DDRX). At higher ECAP temperatures, the kinetics of CDRX are retarded leading to a lower fraction of equiaxed grains/high-angle grain boundaries and a higher fraction of dislocation cell structures. At 523 K, DDRX induces a high fraction of equiaxed grains with a very low dislocation density which appears responsible for the observed high tensile ductility. The sample processed at 523 K possessed a good combination of strength and ductility, suggesting that processing by ECAP at elevated temperatures may be a suitable alternative to RT ECAP processing followed by subsequent annealing.
10.1002-adem.201100113	11	glass; bulk; metallic; bulk metallic; gfa; bmg; glassy; metallic glass; ability; bulk metallic glass; amorphous; addition; crystallization; mm; glass-forming	The effect of titanium addition on the glass forming ability (GFA), plasticity, corrosion resistance and biocompatibility of Cu-Zr-Al alloy are evaluated by XRD, DSC, compression tests, corrosion, and cytotoxicity tests. The GFA of Cu45Zr48Al7 amorphous alloy is greatly improved by titanium addition, as evidenced by the increase of critical size from less than 8 mm for Cu45Zr48Al7 alloy to 10 mm for Cu45Zr46.5Al7Ti1.5 alloy when the samples are prepared by copper mold casting. Cu45Zr46.5Al7Ti1.5 alloy shows enhanced plastic strain up to 10%, good corrosion resistance and biocompatibility in comparison to Cu45Zr48Al7 alloy.
10.1002-adem.201500488	6	grain; deformation; strain; strength; dislocation; cu-; tensile; size; ecap; grain size; sfe; ductility; hardening; high; stress	Pure copper is subjected to severe plastic deformation at room temperature using quasi-constrained high-pressure torsion through 1/4 to 10 turns. The evolution of the microstructure is monitored using X-ray diffraction and electron backscatter diffraction. Specimens are analyzed both before and after micro-compression of approximate to 50%. The results show that after 10 turns there is a homogeneous ultrafine-grained (UFG) microstructure with an average grain size of approximate to 250nm and with a simple shear texture. The micro-compression testing shows that UFG specimens exhibit a better surface quality after compression thereby demonstrating an excellent potential for using UFG copper in micro-forming.
10.1002-adem.201500561	-1		Copper has many applications especially in rotor parts subjected to fatigue loading. From them, a typical copper busbar is chosen to mainly investigate the low-cycle fatigue (LCF) behaviors, fracture morphologies, dislocation patterns and crack initiation mechanism. It is found that with total strain amplitude increasing, cyclic softening appears in all the samples; the fatigue crack initiation sites transform mainly from slip bands to grain boundaries; the dislocation spacing of the post-fatigue samples decreases; by comparison, the Basquin-Manson-Coffin and the simplified hysteresis energy relations are relatively simple and accurate methods to predict fatigue life. Finally, the LCF properties of the coppers with different grain sizes prepared by different technologies are compared and optimized.
10.1002-adem.201600607	8	hot; deformation; strain; strain rate; dynamic; hot deformation; recrystallization; dynamic recrystallization; flow; rate; flow stress; compression; constitutive; degrees; stress	Hot deformation behavior of Cu-Ni-Si and Cu-Ni-Si-Ag alloys is investigated using the Gleeble-1500D simulator in the 600-800 degrees C deformation temperature and 0.01-5s(-1) strain rate ranges. Dynamic recrystallization (DRX) mechanism is a feature of high temperature flow stress-strain curves of the alloy. Microstructure is observed by optical microscopy. Ag addition can refine the grains and accelerate dynamic recrystallization. Characteristic points of the flow stress curves, including critical strain for DRX initiation (E-c), are determined by employing strain hardening rate analysis. Processing maps are developed and analyzed based on the dynamic material model (DMM). Ag addition can optimize the alloy processing workability.
10.1002-adem.201600726	-1		AlxCr0.4CuFe0.4MnNi (x = 0, 0.1, 0.2, 0.3, 0.4) high entropy alloys (HEAs) were prepared by copper-mold casting. The effects of Al were investigated on the microstructure, tensile properties and oxidation behavior of these HEAs. It was shown that the addition of Al resulted in the formation of BCC and ordered BCC phases. The compositional heterogeneity between dendrites and interdendrites was alleviated when the content of Al was small. The mechanical properties of HEAs have been remarkably improved by the addition of Al. Considering the low cost and good mechanical properties, this kind of HEAs is rather competitive among HEAs for engineering application as structural materials. In this work, it was also shown that the oxidation resistance of current HEAs was significantly improved by the addition of Al.
10.1002-adem.201700197	8	hot; deformation; strain; strain rate; dynamic; hot deformation; recrystallization; dynamic recrystallization; flow; rate; flow stress; compression; constitutive; degrees; stress	Hot deformation behavior of two alloys, Cu-Zr and Cu-Zr-Y is studied by compression tests using the Gleeble-1500D thermo-mechanical simulator. Experiments are conducted at 550-900 degrees C temperature and 0.001-10 s(-1) strain rate. The true stress-true strain curves are analyzed, and the results show that the flow stress strongly depends on the temperature and the strain rate. Furthermore, both alloys behave similarly when the flow stress increases with higher strain rate and lower temperature. Based on the dynamic material model, the processing maps are obtained at strains of 0.4 and 0.5. The optimal processing parameters for the Cu-Zr and Cu-Zr-Y alloys are determined. In addition, the constitutive equations for the alloys are established to characterize the flow stress as a function of strain rate and deformation temperature. Based on the microstructure evolution analysis, the results show that the addition of Y can effectively promote dynamic recrystallization. Moreover, the processability of the alloy can be optimized. Thermal deformation activation energy and the peak power dissipation efficiency for the alloys are obtained. It is observed that the addition of Y effectively improves thermal deformation activation energy and has considerable influence on the peak power dissipation efficiency.
10.1002-adem.201700503	6	grain; deformation; strain; strength; dislocation; cu-; tensile; size; ecap; grain size; sfe; ductility; hardening; high; stress	The effect of the initial annealing temperature on the evolution of microstructure and microhardness in high purity OFHC Cu is investigated after processing by HPT. Disks of Cu are annealed for 1 h at two different annealing temperatures, 400 and 800 degrees C, and then processed by HPT at room temperature under a pressure of 6.0 GPa for 1/4, 1/2, 1, 5, and 10 turns. Samples are stored for 6 months after HPT processing to examine the self-annealing effects. Electron backscattered diffraction (EBSD) measurements are recorded for each disk at three positions: center, mid-radius, and near edge. Microhardness measurements are also recorded along the diameters of each disk. Both alloys show rapid hardening and then strain softening in the very early stages of straining due to self-annealing with a clear delay in the onset of softening in the alloy initially annealed at 800 degrees C. This delay is due to the relatively larger initial grain size compared to the alloy initially annealed at 400 degrees C. The final microstructures consist of homogeneous fine grains having average sizes of approximate to 0.28 and approximate to 0.34 mu m for the alloys initially annealed at 400 and 800 degrees C, respectively. A new model is proposed to describe the behavior of the hardness evolution by HPT in high purity OFHC Cu.
10.1002-adem.201700536	6	grain; deformation; strain; strength; dislocation; cu-; tensile; size; ecap; grain size; sfe; ductility; hardening; high; stress	Structure, mechanical, and service properties of a Cu-Cr-Hf alloy after quenching, equal-channel angular pressing (ECAP), and subsequent aging have been studied. The positive effects of ultrafine-grained structure formation (grain/subgrain size of approximate to 200 nm) during ECAP and strengthening particles precipitation upon subsequent aging at 450 degrees C on the mechanical and fatigue properties of the alloy are shown. Ultrafine-grained Cu-Cr-Hf alloy after aging shows increasing in the fatigue limit on the basis of 107 cycles from 185 to 375 MPa relative to that of the initial coarse-grained state. The alloy after ECAP and aging also exhibits sufficient elongation to failure (11.4%) and good electrical conductivity (78% IACS).
10.1002-adem.201701082	1	shape; memory; shape memory; damping; martensite; martensitic; damping capacity; transformation; capacity; strain; superelasticity; temperature; cu-al-mn; shape memory effect; effect	Martensitic stabilization in copper-based shape memory alloys can be suppressed by up-quenching treatment through lowering vacancy concentration. Nevertheless, the up-quenching time should be continuously extended to suppress martensitic stabilization as the recovery heating rate lowered. In terms of cost, it is not advisable to extend the up-quenching time infinitely to suppress the heating rate-dependent martensitic stabilization. In this paper, instead of eliminating vacancies through up-quenching treatment, we focus on reducing vacancies from their origin, that is, the process of solution treatment. We investigate differences in the vacancy concentration and the resulting heating rate-dependent martensitic stabilization in Cu-17.0Al-10.5Mn (at%) alloys subjected to solution treatment with and without constraint. The results show that the vacancy concentration in the unconstrained samples is remarkably lower than that in the constrained ones, leading to the suppression of heating rate-dependent martensitic stabilization. We propose a novel constraint method during solution treatment avoiding shape change and suppressing martensitic stabilization simultaneously.
10.1002-adem.201800372	-1		Shape memory alloys from the Cu-Al-Ni system arouse interest for industrial applications due to their high thermal stability and low cost. In this study, the Cu-11.8Al-3.2Ni-3Mn-0.5Zr alloy is prepared through a powder metallurgy processing technique. Specimens are produced by a conventional uniaxial press followed by sintering procedure under argon atmosphere. The sintering temperature is varied in the range from 950 to 1060 degrees C, whereas sintering time is varied from 0.5 to 2h . The results denote that a temperature close to the alloy's solidus temperature is necessary to achieve higher densities. Moreover, martensite-type microstructures are observed, despite the slow cooling rate applied after sintering. The compression strengths are in the order of 500MPa with the exception of the specimens sintered for 1.5h, which reaches an average of 700MPa. This is explained by the lower porosity resulting from liquid phase sintering. The forward and reverse martensitic transformation temperatures, however, are quite similar for all examined conditions.
10.1002-adem.201800405	-1		Recent advances have enabled the production of nano-grained metallic alloys with a thermally stable microstructure. Consequently, the production of bulk samples and subsequent machining and testing of standardized test specimens is now a real possibility. Therefore, for the first time, the authors report on the in-depth characterization and machinability of bulk nanocrystalline materials. In particular, this study addresses the feasibility of machining and to what extent, if any, the microstructure is altered due to the high stresses and temperature incurred during machining. Toward that goal, a series of copper-tantalum nanocrystalline threaded cylindrical tensile samples are machined from extruded rods. Advanced characterization techniques, such as transmission electron microscopy, are employed which indicated that the grain size of the Cu-Ta alloy was further reduced by approximately one-third. This reduction in grain size is quite noteworthy given an estimated total strain of 260% and moderate temperature increase resulting from the machining operation. This unexpected grain refinement is attributed to tantalum-based nanoclusters dispersed through the matrix which limit grain growth in the initial microstructure during machining. Overall, the authors observe a continuous chip formation and machinability of bulk nanocrystalline materials, which stems from stable nano-grains and having a near elastically perfectly plastic material behavior.
10.1002-adem.201800742	8	hot; deformation; strain; strain rate; dynamic; hot deformation; recrystallization; dynamic recrystallization; flow; rate; flow stress; compression; constitutive; degrees; stress	The flow stress of a Cu-9.83Ni-1.24Fe-0.7Mn-0.012Ce alloy at high temperature is studied by using a thermo-simulation machine. The microstructure is characterized by optical microscopy and transmission electron microscopy. The flow stress and strain increase linearly in the initial stages of hot deformation, and two trends exist after the linear section. When the strain rate exceeds 0.1 s(-1), the flow stress continues to increase with an increase in deformation. When the strain rate is less than 0.1 s(-1), steady-state flow results. A thermal-processing map of the alloy is established based on the dynamic material model. The destabilization zone of the alloy is established for 800-870 degrees C and a strain rate of 0.1-10 s(-1). Subgrains are formed by dynamic recovery with high-density dislocations. The deformation temperature range of safe processing I zone is 800-900 degrees C with a strain rate of 0.01-0.1 s(-1); and the deformation temperature range of safe processing zone II is 900-1000 degrees C with a strain rate of 0.01-10 s(-1). The softening mechanism of recrystallization is conducive to thermal processing.
10.1002-adem.201800859	-1		Nanocrystalline (nc) Cu and Cu-1% Nb bulk materials are synthesized using a combination of cryogenic and room temperature ball milling. The grain size values of these in situ consolidated Cu and Cu-1% Nb, determined using transmission electron microscopy, are found to be 22nm and 18nm, respectively. In this investigation, isochronal heat treatments are performed for 1h to establish grain size and microstructural changes as a function of temperature. The annealing of nc Cu-1% Nb at a temperature of 1073K reveals a slight increase in the average grain size from 18 to 45nm. The grain size of nc Cu, however, increases from 22nm to about 3m after annealing at the same conditions. The present results indicate that solute entrapment plays a major role in thermal stability of the high purity contaminant-free Cu with the addition of only 1at% Nb after annealing for 1h up to a homologous temperature of 0.8. Kinetic stabilization via clustering of Nb atoms on the grain boundaries and the triple junctions is also observed after annealing at high temperature for longer times.
10.1002-adem.201800889	6	grain; deformation; strain; strength; dislocation; cu-; tensile; size; ecap; grain size; sfe; ductility; hardening; high; stress	The mechanical properties of cold-rolled (CR) and partially recrystallized (PRX) Cu-Al alloy are investigated by tensile tests at 77 and 293K. While the uniform elongation is limited for the CR specimens at both temperatures, uniform elongation is enhanced unprecedentedly from 2.4% at 293K to 16.5% at 77K for the PRX specimens. In contrast to the sole contribution of recrystallized grains via wavy slip at 293K, the prominent uniform elongation at 77K is attributed to the multiple deformation mechanisms within recrystallized grains and the harmonization of plastic deformation between recrystallized grains and matrix.
10.1002-adem.201801265	-1		Porous metals have attracted great attention for their functional and structural applications; however, they often possess limited applicability in their pure form for the areas requiring decent strength and corrosion resistance. In this study, pure copper (Cu), pure nickel (Ni), and Cu-Ni alloy foams with five different compositions are successfully fabricated using freeze casting, resulting in open-pore structures with varied porosity (from 55% to 75%). Their varied morphologies and crystal sizes are compared, and the lattice parameters and crystal sizes are calculated. The corrosion resistance of the synthesized Cu-Ni alloy foams is superior to those of the pure Cu and Ni foams. The weight loss rate of the Cu7Ni3 alloy foam is six times and five times slower than those of the pure Ni and pure Cu foams in a sulfuric corrosive environment, respectively. The yield strength of Cu7Ni3 alloy foam (53 +/- 2% porosity) is 72 +/- 2MPa and its yield strength when normalized by the Gibson-Ashby model is the largest with a value of up to 852 +/- 3MPa. The elastic modulus and hardness values are varied in the range of 73.4-152.4GPa and 1.6-4.7GPa, respectively, depending on the composition of the alloy foam.
10.1002-adem.201900333	7	irradiation; shear; grain; ta; deformation; size; radiation; voids; nanocrystalline; simulations; similar; void; temperature; irradiated; boundaries	Nanocrystalline metal alloys show great potential as structural materials, but are often only available in small volumes, such as thin films or powders. However, recent research has suggested that dopant segregation and grain boundary structural transitions between states known as complexions can dramatically alter grain size stability and potentially enable activated sintering. Herein, strategic consolidation routes for mechanically alloyed Cu-4 at% Zr powders are explored to capture the effects of amorphous complexion formation on the densification of bulk nanostructured metals. An increase in the density of the consolidated samples is observed, which coincides with the formation of amorphous intergranular films. At the same time, the grain size is reasonably stable after exposure to these temperatures. As a result, a bulk nanograined metal with a grain size of 57 nm and a density of 99.8% is produced, which shows an impressive balance of small grain size and high density using simple consolidation techniques.
10.1002-adem.201900429	6	grain; deformation; strain; strength; dislocation; cu-; tensile; size; ecap; grain size; sfe; ductility; hardening; high; stress	Cu-Ni alloys and pure Cu and Ni are processed by severe plastic deformation up to different selected strain levels. States of varying grain sizes and hardnesses are adjusted by selecting the total torsional strain up to saturation and subsequent thermal annealing. The hardnesses of the annealed saturation-deformed microstructures can be described by Hall-Petch parameters valid for relaxed coarse-grained samples. The processing conditions determine the Hall-Petch parameters in a similar way for each composition. It is concluded that relaxation and recovery modify the fine-grained saturation-deformed microstructures in a way that the influence of grain boundaries (GBs) on the hardness is as in a relaxed coarse-grained microstructure. This observation also indicates that GBs and their character present in fine-grained severe plastically deformed materials possess similar properties concerning dislocation blockage and nucleation as in a relaxed coarse-grained microstructure. The deformation behavior of alloys and pure materials shows distinct characteristics: Alloys reach the grain size of the saturation-deformed microstructure for smaller degrees of deformation, whereas pure materials reach saturation-deformed hardness for smaller degrees of deformation. Thus, the dislocation and GB mobility are the dominating parameters for grain refinement and strengthening.
10.1002-adem.201900474	-1		Liquid-metal infiltrated Cu30Mo70 (wt%) is subjected to severe plastic deformation using high-pressure torsion. The initially equiaxed dual-phase structure is gradually transformed into a lamellar structure composed of individual Cu and Mo layers. The thickness of the lamellae varies between the micro- and nanometer ranges depending on the amount of applied strain. Consistent with the refinement of the microstructural features, strength and hardness substantially increase. In addition, an acceptable ductility is found in the intermediate deformation range. An assessment of the damage tolerance of the produced composites is performed by measuring the fracture toughness in different crack propagation directions. The results indicate the development of a pronounced anisotropy with increasing degree of deformation which is an effect of the concurrent alignment of the nanostructured lamellar composite into the shear plane.
10.1002-adem.202100249	15	aging; strength; conductivity; electrical conductivity; electrical; mpa; treatment; strengthening; degrees; cu-; cold; precipitation; tensile strength; tensile; iacs	Electropulsing aging treatment (EAT) can achieve a significant increase in the strength and conductivity of a Cu-Ni-Si alloy in a short time while maintaining a lower temperature. Compared with aging treatment in a conventional heating furnace at 450 degrees C for 120 min, EAT can reach or even exceed the same strength and conductivity in only 5 min. The mechanical and electrical properties of samples treated with 630 and 680 A mm(-2) current density are prominently improved. After 45 min of treatment with 680 A mm(-2) current density, the tensile strength exceeds 600 MPa, and the conductivity reaches 33.45% International Annealed Copper Standard. The main precipitates of the EAT sample is the delta-Ni2Si nanoscale strengthening phase, and there is also the beta-Ni3Si phase in the copper matrix. The strengthening mechanism is the localized Joule heating generated by the electropulsing and the kinetic energy conversion caused by drift electrons, which increases the migration rate of solute atoms Si and Ni and reduces the energy barrier required in the precipitation process, thereby accelerating the formation of precipitates. EAT has the potential to become a new process for the preparation of high-strength and high-conductivity copper alloys.
10.1002-adem.202100716	-1		Selective laser melting is an additive manufacturing technique that can be used to achieve excellent forming of Cu alloys. Specifically, high-Sn-Cu alloys (e.g., Cu-10Sn) offer good wear and corrosion resistance, and are extensively used in industrial applications. Although P is considered a beneficial element in Cu-Sn alloys, particularly with respect to ductility, P-doped Cu-10Sn alloy (Cu-10Sn-0.4P) has not yet been investigated in detail. Thus, herein, it provides valuable insights regarding the printability, residual stress level, heat treatment conditions, mechanical properties, and microstructural features of selective laser melted Cu-10Sn-0.4P. The alloy is successfully printed using a relatively wide range of processing parameters. The high levels of residual stress after printing were relieved using heat treatment under appropriate conditions. Consequently, a good combination of strength, ductility, and hardness was achieved. The addition of P led to an improved oxygen scavenging capability, thus Cu-10Sn-0.4P alloy exhibited a better ductility than P-free Cu-Sn alloy. The excellent printability of Cu-10Sn-0.4P is demonstrated by printing a variety of objects, including flanges, sheathings, and jewelry rings.
10.1002-adem.202100755	-1		This article studies copper (Cu)-based composites alloyed with nickel (Ni) and reinforced with carbon nanotubes (CNTs) fabricated via powder metallurgy under pressureless sintering methodology and vacuum. Different compositions of matrices containing 0, 3, and 30 wt% Ni are compared after sintering at 550 and 750 degrees C. The formation of phases for the different compositions is analyzed by high-temperature X-ray diffraction (HT-XRD) in the solid-state range up to 800 degrees C, in which reduction of oxides along with the sintering can be identified. Subsequently, the matrices are reinforced with pristine multiwalled CNT (MWCNT) in contents of 0, 0.5, and 1.0 wt% prior to sintering, whose dispersion is influenced by the powder's morphology. A custom-made electrical contact resistance (ECR) setup is used to investigate the electrical behavior of the sintered samples, which, particularly, allows the identification of improvements in electrical conduction of samples containing 0.5 wt% CNT and 3 wt% Ni. A reduction in chemical incompatibilities between Cu and CNT can be attributed to the presence of Ni in solid solution.
10.1002-adem.202101169	-1		Alumina dispersion strengthened copper (DS-Cu) shows excellent properties regarding mechanical behavior, thermal stability, thermal conductivity, and radiation resistance, making it a promising candidate of heat sink materials for fusion divertor applications. Compared to mechanical alloying, traditional internal oxidation route has merits of reduced contamination and capability of mass production. However, the tailoring of oxide particles, either intra- or intergranular, is essential to further improve the properties of DS-Cu fabricated through internal oxidation route. Herein, the origins of coarsening and agglomeration of alumina particles are uncovered through a dedicated combining investigation between powder metallurgy and Rhines-pack method, and contributing factors, such as grain boundaries, diffusion distance, concentration of Al, atomization, and the existence of water vapor, are identified. The effects of Ti doping on tailoring the size, shape, and distribution of intergranular and intragranular particles are demonstrated also. This study is of significance for the further improvement of properties of DS-Cu fabricated with the combination of powder metallurgy and internal oxidation.
10.1002-adem.202101403	-1		The microstructures and properties of Cu-xCr-0.4Nb alloys were investigated by changing Cr composition and cooling mode. The as-cast microstructures and fracture morphologies were observed by SEM. The morphology and size of the precipitated phase were observed by TEM. The hardness, electrical conductivity, and tensile strength of the resulting alloys were also tested. For Cu-xCr-0.4Nb alloys cooled in furnace, Cr2Nb particles were formed near the eutectic regions, and destroy the continuity of the eutectic regions. The Cu-Cr-Nb alloys casted in copper mold can significantly increase the solid solubility of solute elements. The microstructures are finer cellular crystals without the segregation of Cr2Nb particle. It makes the microstructures more homogeneous and greatly improves the hardness. After aging, Cr and Cr2Nb particles with the scale of 5 approximate to 10 nm were precipitated in the copper matrix. The hardness, conductivity and tensile strength can reach to 142HB, 90.52% International Annealed Copper Standard (IACS) and 427 MPa, respectively. In addition, after the alloy being softened, the Cr2Nb particles were found near the Cr particles by TEM, which inhibited the high-temperature coarsening of precipitated Cr phase. The softening temperature of Cu-1.0Cr-0.4Nb alloy reaches 600 degrees C.
10.1002-adem.202200653	-1		The crystallizer is the key component controlling the solidification process and is mainly made of pure Cu. The poor wear resistance and oxidation resistance of pure Cu limit the working life of the Cu crystallizer. Herein, Fe/FeCr coatings are designed and successfully fabricated on the Cu substrate by laser cladding technique. The composition, microstructure, mechanical, and thermal properties of the Cu-Fe/FeCr composite are investigated. The coating is composed of a body-centered cubic Fe-Cr alloy phase. The grains on the surface are equiaxed grains with an average diameter of 2 mu m. The coating exhibits a tensile strength 3 times of Cu substrate and well elongation thanks to the fine-grain structure. The interface between coating and substrate is metallic bonding and possesses a shear strength of as high as 200 MPa. The coating shows obvious advantages in wear resistance and antioxidation at high temperatures in comparison to Cu substrate. The laser cladding Cu-Fe/FeCr composite is promising to prolong crystallizer life for continuous casting.
10.1002-adem.202200833	-1		Al-Ti-Ni composite coatings with different Ti contents (wt% = 20, 25, 30, 35) are prepared on the surface of 90/10 copper-nickel alloy using selective laser melting. The microstructure and phase composition of the coatings are characterized by scanning electron microscopy, X-ray diffraction, and energy-dispersive spectrometry, and the corrosion resistance of the four coatings and the 90/10 copper-nickel alloy in 3.5 wt% NaCl solution is investigated. The coatings exhibit a good metallurgical bonding with the substrate, and passive films are formed on the surfaces of the coatings after 6 h of potentiostatic polarization. The coating with a Ti content of 30% has the most compact passive film and the best corrosion protection performance due to the minimal Ti2O3 content in the passive film, which greatly improves the stability of the passive film. The immersion corrosion mechanism of the coating is pitting corrosion. Electrochemical tests show that the corrosion current density of all four coatings is one order of magnitude lower than that of the substrate, and the coating with a Ti content of 30% has the lowest corrosion current density, indicating that this coating could significantly improve the corrosion resistance of the substrate.
10.1002-adem.202201241	-1		Cu-Co-Si alloys are being intensively studied as alternative candidates for Cu-Ni-Si alloys for integrated circuit lead frames. However, the effects of different precipitate types on the comprehensive properties of Cu-Co-Si alloys are not clear. Herein, several Cu-Co-Si alloys with various precipitates (CoSi, Co2Si, and Co) are designed based on phase diagrams calculation. The designed alloys are melted, cold-rolled, and aged to test the corresponding hardness and electrical conductivity (EC). X-ray diffraction and transmission electron microscopy are utilized to analyze the precipitates generated in those alloys. In the alloys with Co/Si <= 1, the excess Si atoms are not easy to precipitate from the copper lattice after CoSi precipitation, which seriously damages the EC. Co-precipitation in alloys with Co/Si > 2 is beneficial to improve EC without sacrificing hardness. According to thermodynamic calculation, precipitates in Cu-1.62Co-0.35Si (wt%) alloy with total elements between 1.5 and 2.0 wt% are all Co2Si and have the highest mass fraction in the equilibrium state. The different precipitates are highly dependent on the Co/Si atomic ratio and essential to Cu-Co-Si alloys' mechanical and electrical performances.
10.1002-adem.202201271	-1		The preparation of Cu-Ti alloys with homogenous elemental distribution is related to the engineering applications. Considering the thickness ratio and cross-sectional geometry of components change with the increase in cumulative equivalent strain in accumulative roll bonding-deformation diffusion (ARB-DD) process, an elemental diffusion model is established based on different solute concentration fields. The accuracy of the model is verified by preparing Cu-Ti alloys in different states. The morphology of Ti layers evolve from a flat to a shuttle-shaped structure due to the strong shear effect as cumulative equivalent strain increases. The diffusion heat treatment time for homogenization is predicted based on the model, and the results show that the model basically matches with the experimental results. The absolute error of prediction is within 9%, and the average error is about 4.4%. It indicates that the synergistic control of elemental diffusion behavior in ARB-DD process can be achieved. Besides, it demonstrates that the effective diffusion activation plays a key role in determining the accuracy of the model. The difference of deformation energy storage in various cumulative equivalent strain states causes a significant change in effective diffusion activation energy, thereby producing a great influence on elemental diffusion behavior of Cu/Ti alloys.
10.1002-adem.202201913	8	hot; deformation; strain; strain rate; dynamic; hot deformation; recrystallization; dynamic recrystallization; flow; rate; flow stress; compression; constitutive; degrees; stress	Cu-Ti-Ni-Mg and Cu-Ti-Ni-Mg-Ce alloys are prepared by vacuum induction melting. The hot deformation tests of the two alloys are carried out on the Gleeble-1500 simulator under the deformation temperatures of 550-950 degrees C and strain rates of 0.001-10 s(-1). The true stress-strain curves of the two alloys are obtained and the constitutive equations are established. The activation energy of the Cu-Ti-Ni-Mg alloy is 344.02 kJ mol(-1), and the activation energy of the Cu-Ti-Ni-Mg-Ce alloy is 389.87 kJ mol(-1). Based on the processing maps, the optimal processing parameters of the two alloys are obtained. The microstructure of the two alloys is analyzed by electron backscatter diffraction (EBSD) and transmission electron microscopy (TEM). The addition of Ce reduces the dislocation density and texture strength . The CuNi2Ti precipitates are found in both alloys, and there are more precipitates in the Cu-Ti-Ni-Mg-Ce alloys. The addition of Ce increases the flow stress and activation energy, promotes precipitation, and improves the deformation resistance of the alloys.
10.1002-adem.202300742	-1		The cold angular rolling process (CARP) is being developed as a continuous severe plastic deformation technique, which can process metal sheets without any length limitations at room temperature. CARP contains cold rolling and equal-channel angular process components. The sheet thickness is kept consistent before and after CARP, allowing multiple passes of the sheet. The desired microstructure and mechanical properties can be achieved in the processed metallic sheets. The current study is aimed to evaluate the capability of CARP by processing copper sheets with different sheet widths for repetitive passes. The CARP-treated sheets are examined by lab-scale X-ray and high-energy synchrotron X-ray diffraction to investigate the evolution in dislocation density, texture, and strain anisotropy, and by tensile testing to identify the bulk mechanical properties. The digital image correlation method is applied to tensile testing so that strain localization within the sample gauge is visualized and deformation behavior is evaluated after yielding till postnecking by estimating the hardening exponent and strain hardening rate of the CARP-treated sheet. Comparing the reported continuous and multiple-step processes on Cu and its alloys, the present study confirms that the CARP is potentially a useful sheet process for strengthening ductile metals. This report demonstrates the capability of the cold angular rolling process (CARP) for a continuous severe plastic deformation process for sheets. Miniaturized tensile testing with the digital image correlation method and synchrotron high-energy X-ray are applied to characterize plastic deformation behavior and microstructural and texture transformations of the CARP-treated Cu sheets over large length scales.image & COPY; 2023 WILEY-VCH GmbH
10.1002-adem.202300928	-1		To address the challenges associated with preparation of nanoporous Cu-Ni (NP-CuNi) alloys containing high Ni concentrations, a Ni2+-assisted dealloying strategy is proposed. The proposed strategy involves a three-stage dealloying process primarily driven by dynamic Ni deposition/dissolution. The Ni concentration in NP-CuNi is tuned by altering the Ni content of the Cu-Mn precursor alloy and Ni2+ in a H2SO4 solution. The Ni concentration of the nanoporous Cu66.5Ni28.5Mn5 alloy prepared in a H2SO4 + NiSO4 solution is increased by 5.2 times compared to that of the alloy prepared in the H2SO4 solution alone. Moreover, the corrosion resistance test demonstrates a reduction in corrosion current density by 58.3% compared to NP-Cu.
10.1002-adem.202300944	-1		The Cu-1.1 wt% Hf-0.1 wt% Si alloy containing various precipitates is studied as a novel precipitation-strengthened alloy with high strength and high electrical conductivity. The Cu-Hf-Si alloy prepared by solution, cold rolling, and aging processes exhibits a hardness of 238.92 HV, a tensile strength of 691.01 MPa, a breaking elongation of 15.09%, and an electrical conductivity of 62.34% International Annealed Copper Standard. The optimal peak aging parameter for Cu-Hf-Si alloy is 430 & DEG;C for 90 min. The precipitation of Hf and Si atoms from the Cu matrix is helpful to enhance the electrical conductivity. The precipitation of Hf can produce fibrous Guinier Preston zone and & gamma;' precipitate, as well as spherical Cu10Hf7 phases. In addition, the coprecipitation of Si and Hf can also produce Hf3(Cu2Si)2 and HfCuSi phases. The high strength of Cu-Hf-Si alloy is mainly due to the multiprecipitates synergistic strengthening. A novel precipitation-strengthened Cu-1.1 wt% Hf-0.1 wt% Si alloy with high strength and high electrical conductivity is prepared by solution, cold-rolling, and aging processes. The precipitation of Hf and Si atoms from the matrix is helpful to enhance the electrical conductivity. The high strength of Cu-Hf-Si alloy is mainly due to the multiprecipitates synergistic strengthening.image & COPY; 2023 WILEY-VCH GmbH
10.1002-adem.202301224	-1		Cu-based shape-memory alloys (Cu-based SMAs) demonstrate prospects in active heat sinks due to their excellent thermal conductivity, high transformation temperature, and low cost. However, their inferior mechanical properties have hindered their industrial application. Previous studies have indicated that mechanical properties can be improved by decreasing grain size and minimizing microstructural segregation, which can be achieved by laser powder bed fusion (LPBF) process. This work investigates the influence of process parameters on the processability, microstructure, and shape-memory effect (SME) of 81.95Cu-11.85Al-3.2Ni-3Mn (wt%) thin-walled samples fabricated by LPBF. Results reveal that laser power and scanning speed significantly affect the relative density of the Cu-based SMA thin-walled samples, and higher laser power and scanning speed contribute to better processability. Additionally, the high cooling rate during the LPBF process facilitates the formation of beta 1 ' martensite without requiring posttreatment, and the size of the beta 1 ' martensite decreases with increasing scanning speed. In bending-recovery experiments, specimens fabricated at higher scanning speed exhibit the highest SME recovery rate and bending angle. Moreover, the test confirms that Cu-based SMA formed at lower scanning speeds exhibits even higher thermal conductivity. This work shows the potential of fabricating high-performance Cu-based SMA components by LPBF. Higher laser power and scanning speed contribute to better processability of the Cu-based shape-memory alloy (SMA) thin-walled samples. The high cooling rate during the laser powder bed fusion process facilitates the formation of beta 1 ' martensite. Forming Cu-based SMA at higher scanning speeds results in smaller beta 1 ' martensite sizes, the highest shape-memory effect recovery rate, and the highest bending angles.image (c) 2023 WILEY-VCH GmbH
10.1002-adem.202301618	8	hot; deformation; strain; strain rate; dynamic; hot deformation; recrystallization; dynamic recrystallization; flow; rate; flow stress; compression; constitutive; degrees; stress	Hot compression experiments with the deformation temperatures of 750-950 degrees C and the strain rates of 0.01-10 s-1 are carried out on a Gleeble-3500 thermal-mechanical simulator. The flow behavior and dynamic recrystallization (DRX) mechanism of the Cu-Ti-Fe alloy are systematically studied under different hot deformation conditions. According to the curves of flow stress and work hardening rate, the DRX critical condition of the alloy is obtained, and the critical stress value of DRX is small under high-temperature and low-strain rate. After fitting, the logarithmic values of the critical stress and critical strain have a linear relationship with lnZ, which indicates that the alloy is more prone to DRX at high temperatures and low-strain rates. The Arrhenius constitutive model of the alloy is established, the linear correlation coefficient (R2) is 0.984. Combined with the microstructure of Cu-Ti-Fe alloy, the microstructure evolution characteristics and DRX mechanism are elucidated. The dominant mechanism of the alloy under the deformation temperature of 750-950 degrees C is the DRX mechanism. The low-angle grain boundaries (LAGBs) transform into high-angle grain boundaries (HAGBs) and continuous dynamic recrystallization (CDRX) grains form. Abundant dislocations gather near the HAGBs, causing grain boundaries to protrude. High-temperature conditions make the dislocations disappear, forming discontinuous dynamic recrystallization (DDRX) grains. The dominant mechanism of the Cu-Ti-Fe alloy under the deformation temperature of 750-950 degrees C is the dynamic recrystallization (DRX) mechanism. The dislocation density increases, subgrains containing low-angle grain boundaries (LAGBs) are rearranged by dislocations, the LAGBs transform into high-angle grain boundaries (HAGBs) and continuous dynamic recrystallization (CDRX) grains form. Abundant dislocations gather near the HAGBs, causing grain boundaries to protrude. High-temperature conditions make the dislocations disappear, forming discontinuous dynamic recrystallization (DDRX) grains.image (c) 2023 WILEY-VCH GmbH
10.1002-adem.202301750	-1		In this work, it is aimed to improve the deformation ability of the Al2O3 dispersion strengthened copper sintered billet by building heterogeneous structure with addition of different sizes of particle. Using the modified mixture model and equal work law, the stress distribution model of heterogeneous materials is derived. In the results, it is shown that higher deformation temperature and lower strain rate are conducive to steady deformation. Under the conditions of 950 degrees C and 0.01 s(-1), the stress distribution coefficients from low to high are 10, 25, and 5 mu m, respectively, when the strain is 0.1. The strain contribution rates of softness of the sintered billet are 45.5%, 62.1%, and 42.6%, respectively. The addition of 10 mu m particle size copper powder can significantly improve the deformation capacity of the sintered billet. It is found that with the increase of the particle size of copper powder, the density of the microgeometrically necessary dislocation of the hot extrusion dispersed copper is lower. The reason is that the different particle size of copper powder leads to the different distribution in powder stacking, which affects the difficulty of harmonizing the deformation of soft and hard and the number of dislocation in the hot-extrusion process of sintered billet.
10.1002-adem.202302282	-1		Herein, Cu/Al/Ag-layered composites with two silver powder concentrations (2 wt% and 3 wt%) are fabricated with the aid of accumulative roll bonding (ARB). The ARB-ed samples are heat treated at different temperatures (750, 850, 950, and 1050 degrees C), times (30, 45, and 60 min), and cycles (1-9 cycles) to produce Cu-Al-Ag shape memory alloys. The samples are characterized by X-ray diffraction, scanning electron microscope, and electron backscattering diffraction. Phase transformation temperatures are measured by differential scanning calorimetry. Strain recovery and shape memory behavior are evaluated by bending and tensile tests, respectively. The results indicate that alloys containing 2 wt% Ag, rolled till 9 cycles, heat treated at 950 degrees C for 60 min, and samples with 3 wt% Ag, fabricated by 9 cycles, annealed at 850 degrees C for 60 min show maximum beta martensite phase amount. The strain recovery ratios of the first and second samples are 71.7% and 71.2%, respectively. Additionally, the tensile test shows that the residual plastic strain and the recovered strain for the first sample with 2 wt% Ag are equal to 0.7% and 3.0%, respectively. These results for the second sample with 3 wt% Ag are 1.2% and 3.4%, respectively. The results of this work show that to obtain shape memory effect (SME) in Cu-11Al-xAg (x = 2-3 wt%), the samples must have a homogeneous microstructure with proper amount of beta martensite phase. Rolling the samples untill 9 accumulative roll bonding cycles alongside with annealing them to 850-950 degrees C, ends in sufficient SME with strain recovery of approximate to 72%.image (c) 2024 WILEY-VCH GmbH
10.1002-adem.202400266	-1		Cu/Nb laminated metallic composites (LMCs) exhibit extraordinary mechanical strength while electrical conductivity is maintained at a high level. In this research, Cu-based LMCs with varying volume fraction of niobium are produced via accumulative roll bonding (ARB) and additionally cold-rolled and heat-treated to identify the role of these heterogeneous phase boundaries on the overall sheet properties. Deformation structures in these layered materials are studied through scanning transmission electron microscopy investigations. The existence of an interface-affected zone at the phase boundaries and mechanical intermixing is attributed to decreasing electrical and increasing mechanical properties, especially in very thin layered LMCs. Atom probe tomography measurements show that mechanical alloying occurs due to severe plastic deformation during ARB processing of the laminates. An additional subsequent heat treatment leads to chemical demixing at the interfaces of the phase boundaries. Accumulative roll bonding-processed Cu/Nb laminated metallic composites show a transition layer thickness, where the strengthening behavior changes and conductivity starts to decrease due to the existence of an interface-affected zone originating from heterodeformation at the phase boundaries. Microstructural, mechanical, and electrical tests are performed to shed light on the influence of lamellar heterostructured materials and their outstanding properties.image (c) 2024 WILEY-VCH GmbH
10.1002-adem.202400404	-1		Face-centered cubic (FCC) metals are widely used in the field of structural materials due to their excellent mechanical properties, and their fatigue behaviors have always been a focus of attention. Herein, 1060 aluminum alloys with different processing states and copper are selected to study the high cycle fatigue performance at room temperature and high temperature. The fracture morphology and dislocation evolution are characterized through characterization methods such as scanning electron microscope and transmission electron microscope. Based on the research, the main movement mode of dislocations (plane slip or wavy slip) are influenced by stacking fault energy (SFE), which further has a significant impact on fatigue performance. When the SFE of the FCC metal is higher, wavy slip dominates and the material is sensitive to temperature changes; on the contrary, during cyclic loadings, metal with lower SFE is dominated by plane slip, due to the reversibility of plane slip, the damage to the material with low SFE under fatigue loading is more uniform. For face-centered cubic (FCC) metals with low stacking fault energy (SFE), the movement of dislocations is dominated by planar slip. Under the situation of higher energy inputs, dislocations gradually adjust from disorder to ordered dislocation configurations; for FCC metals with very high SFE, the plastic deformation of the material is controlled by wavy slip.image (c) 2024 WILEY-VCH GmbH
10.1002-adem.202400533	16	wear; composite; composites; powders; milling; particles; powder; wt; sliding; friction; hardness; matrix; mechanical; surface; properties	The Ni self-lubricating coatings on copper substrates are deposited by electrodeposition using an aqueous electrolyte at room temperature. These coatings have the potential to improve the service life of Cu as a structural component in high-temperature abrasion environments. A combination of low wear rate and coefficient of friction (CoF) is required in the coatings. Herein, friction and wear characteristics of the deposited Ni coatings are done by a ball-on-disc tribometer operated in the temperature range of 25-500 degrees C. The morphology and wear mechanism of tribo/transfer films are investigated using X-ray diffraction, X-ray photoelectron spectroscopy, and scanning electron microscopy. The CoF of Ni coating is substantially lower (CoF 0.37) at 500 degrees C than the Cu-substrate, which is 0.79 at 25 degrees C. The Ni-coating also reveals a low wear rate due to the formation of in situ oxides of Ni and Cu on sliding surfaces at high temperatures. The wear rate and coefficient of friction (CoF) of the deposited Ni-coatings are characterized as a function of temperature. The lowest CoF is observed at 500 degrees C, and it is 47.5% lower than at 25 degrees C due to the formation of self-lubricating oxide films. The wear rate and CoF of Ni coating are 3.7 x 10-4 mm3N-1m and 0.375 at 500 degrees C, respectively. image (c) 2024 WILEY-VCH GmbH
10.1002-adem.202400604	-1		In this work, nanomechanical properties for Cu and Cu-Al (where Al = 2, 4, 6, and 8 wt%) alloys are determined using nanoindentation with Berkovich tip. Nanoindentation experiments are performed using trapezoidal load function where maximum load (Pm) varies from 1000 to 9000 mu N at an equal interval of 1000 mu N by maintaining equal loading and unloading rate. It is found that Cu8Al sample shows lower depth of penetration (h) at any load (P) in comparison to other samples due to more pinning of dislocations or hinderance of the dislocation movement by solute (Al) atoms during nanoindentation deformation. In addition, it is observed that the recovery is maximum for Cu8Al sample among all samples; however, this recovery is reducing with the increasing Pm for all samples. Thereafter, the elasticity and plasticity index are calculated from the area under the P-h curves, which shows that the elastic index is maximum for Cu8Al and minimum for Cu. Furthermore, the nanomechanical properties (reduced elastic modulus [Er] and hardness [H]) are reported for all samples and significant indentation size effect is observed for Cu8Al due to dislocation structure during deformation. Nanomechanical properties for Cu-Al system are determined using nanoindentation. In the results, reduction in depth of penetration and increment in recovery at a particular load upon addition of Al atoms are shown. This happens due to high probability of dislocation interaction with other dislocations and Al atoms, which restricts dislocation movement for further plastic deformation.image (c) 2024 WILEY-VCH GmbH
10.1002-adem.202400616	-1		A new strategy has been developed to combine the nanotwins and dual-scale particles into copper matrix composites and the comprehensive properties of Cu-1Cr-0.3Zr-1ZrB(2) exhibit excellently with the addition of intermediate aging and cryorolling. The effects of different deformation processes on the evolution of microstructure, room temperature, and elevated-temperature mechanical properties are investigated. The result demonstrates that the number of nanoscale Cr precipitates increases obviously after intermediate aging. The nanosized Cr precipitates impede the movement of grain boundaries and dislocations, resulting in the refinement of deformation bands and the dislocation tangle. The combined effect of intermediate aging and cryorolling also improves the formation of nanotwins, which plays an important role in enhancing the tensile strength of composites. The tensile strength, elongation, and conductivities of the composites subjected to two-step cryorolling reach 653 MPa, 8.02%, and 79.51% IACS, respectively, showing an optimum comprehensive property. In addition, the stable nanotwins and the uniform distribution of dual-scale particles inhibit the recrystallization process at elevated temperatures, contributing to improving the mechanical behavior at elevated temperatures and heat-resistant performance of composites.
10.1002-adem.202401507	-1		Cu-Ni-Si alloy is widely used as the main material of lead frame. The process of alloying is an important method to improve the comprehensive performance of the alloy. Herein, Cu-1.8Ni-0.45Si (-0.5Zn) alloys are prepared. The variation trend and mechanism of Zn on the mechanical properties and welding properties are analyzed with scanning electron microscopy and electron backscattering diffraction. The results show that the addition of 0.5 wt% Zn can improve the brazing properties of the alloy while ensuring the tensile strength and conductivity of the material. Further quantitative analysis reveals that Zn addition enhances the contribution of precipitation strengthening to the alloy's mechanical properties, which is due to the reduction of the size of the particles of the precipitated phase by the addition of Zn. In addition, the addition of Zn can form a Zn-enriched layer at the welding interface of the alloy, which has an obstructive effect on the diffusion and growth of the intermetallic compound (IMC) layer, effectively reducing the thickness of the IMC layer, inhibiting the formation of the Cu3Sn phase, and improving the mechanical properties of the alloy brazed joints.
10.1002-adem.202401523	-1		A high demand for oxide dispersion strengthened (ODS) materials arose in wide fields of application. The electroless plating method has been presented as an elegant way to overcome different surface energies and obtain metal-plated ceramics. However, copper electroless plating is still performed under harsh conditions with toxic and expensive reagents, including noble metals and harsh reducing agents like formaldehyde and hydrazine. To create a pure copper metal matrix in an environmentally friendly and efficient way a previously reported method is advanced in a way that naturally occurring amino acids are utilized. A screening of several amino acids leads to an improvement in phase purity and atomic efficiency. Therefore, a Maillard type reaction with lysine as amino compound is reported to show the best results in the particle coating for all ceramic nanoparticles evaluated. The metal plating results in uniform round micro particles showing a homogeneous coating. In order to obtain copper matrix composites, the prepared particles are successfully implemented in a PBF-LB/M process after mixing with a highly conductive copper alloy. The resulting products were investigated by transmission electron microscopy, scanning electron microscopy, powder X-ray diffraction, and optical density measurements. This work presents the manufacturing of copper-plated ceramic nanoparticles in an environmentally friendly way. Supported by organic functionalizations with pectin an electroless plating step can be performed. Sustainable reagents like xylose, and several amino acids are used for the reduction process. The resulting particles are implemented in a PBF-LB/M process showing the processability to create Cu oxide dispersion strengthened materials.image (c) 2024 WILEY-VCH GmbH
10.1002-adem.202401670	16	wear; composite; composites; powders; milling; particles; powder; wt; sliding; friction; hardness; matrix; mechanical; surface; properties	Copper and its alloys are widely used in the preparation of metal matrix composites due to their thermal and electrical conductivity. This study aims to improve the mechanical, tribological and electrical conductivity properties of copper (Cu) matrix powders by adding certain amounts (10 wt%) of reduced graphene oxide (rGO) nanopowder, boron (B), nitrogen (N) and silicon (Si) reinforced rGO nanopowder. Hybrid composites were produced by powder metallurgy production methods. The samples were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDX) and Fourier-transform infrared spectroscopy (FT-IR) analysis for reinforcement, homogeneity and phase identification. The mechanical and tribological properties of the hybrid composites were investigated by hardness, wear tests and temperature dependent electrical conductivity tests to determine the effect of the reinforcement materials on the Cu matrix structure. The maximum hardness value was obtained from the (Cu-rGO-Si-B-N) hybrid composite with an increase of 193% compared to the pure Cu sample. When the coefficient of friction values of RGO and reinforced rGO hybrid composites were examined, a 219.12% lower coefficient of friction value was observed in the (Cu-rGO-Si-B-N) sample compared to the pure Cu sample. The highest value was observed in the temperature dependent electrical resistance analysis in the rGO reinforced sample.
10.1002-adem.202401728	-1		Cu-Al alloy with a gradient nanostructured surface layer is prepared by ultrasonic shot peening (USP). The effect of different shot peening times on the microstructure and properties of the modified layer is systematically investigated. The results show that the surface phase structure is not changed by USP technology, but a gradient nanocrystalline layer is formed on the surface, and the surface grains are obviously refined. The nanocrystalline mechanism is characterized by dislocation movement and mechanical twinning. USP can greatly improve the mechanical properties, tribological properties, and corrosion properties of the alloy. When the shot peening time is 15 min, the modification effect is the best. The hardness is as high as 254.1 HV0.2, which is 2.4 times that of the matrix, and the average coefficient of friction is only 0.231. The volume wear amount and volume wear rate are 4.434 x 107 mu m3 and 0.1848 mu m2 N-1, respectively. The strengthening mechanism of nanosized samples is grain refinement and work hardening, and the wear mechanism is abrasive wear and slight oxidation wear. The improvement of the corrosion performance of nanosized samples is mainly due to the formation of the dense passivation film on the surface.
10.1002-adem.202401747	-1		Herein, 3D printing involving metallic materials with substantially distinct melting temperatures and their immiscibility presents a formidable challenge. Nevertheless, it may be possible to overcome this challenge using the direct ink writing (DIW) method within such immiscible systems. In this article, a successful fabrication of Cu-based composites utilizing the additive manufacturing process that is DIW technique, followed by a post-sintering process, is presented. The secondary addition to the Cu-matrix includes tantalum (Ta), tungsten (W), and niobium (Nb). The rheological properties of the composite inks are also analyzed for the DIW technique. The underlying reasons behind the increased mechanical, wear, and thermal properties are assessed through experimental and molecular dynamics simulations. Microstructural analysis is conducted using optical and scanning electron microscopes. Mechanical, electrical, thermal, and wear properties are evaluated at ambient temperature, and comparisons are established with DIW-processed pure Cu. Elemental mapping through energy-dispersive spectroscopy and high-resolution transmission electron microscopy confirm the distribution of W, Ta, and Nb particles within the composite. The 3D printing of immiscible alloy components opens new avenues for exploring novel material properties, mixtures, and composite materials, thus fostering the development of innovative materials. The direct ink writing process can be utilized for creating metal matrix (copper (Cu)) composites with immiscible metallic reinforcements/dispersion (tungsten [W], niobium [Nb], and tantalum [Ta]). The composites demonstrate a superior combination of hardness and compressive yield strength . The molecular dynamics simulations suggest that the interface between dispersion and Cu-matrix plays important role in enhanced mechanical properties.image (c) 2024 WILEY-VCH GmbH
10.1002-adem.202401917	15	aging; strength; conductivity; electrical conductivity; electrical; mpa; treatment; strengthening; degrees; cu-; cold; precipitation; tensile strength; tensile; iacs	Herein, large electrical conductivity of 21% IACS and high strength of 1118 MPa in the Cu-3.3 wt%Ti alloy are successfully achieved based on the coupling control of microalloying, deformation, and aging. It is revealed that compared with the Mg-free Cu-3.3 wt%Ti alloy prepared by traditional treatment methods, such as aging, deformation + aging, and the novel method of preaging + cold rolling + aging, both the addition of 0.1 wt%Mg and the novel method of preaging + cold rolling + aging not only can greatly improve the uniform distribution level of dislocation formed during cold rolling and reduce the average size of precipitates, but also can significantly improve the formation of multiscale precipitates with higher volume fraction and their coupling distribution with dislocations, which effectively improve the electrical conductivity and strengthening contribution of precipitates and dislocation simultaneously. The results shed light on the understanding of related mechanisms in Cu-Ti alloys and hopefully also provide theoretical guidance for industrial production and applications of Cu-Ti alloys with excellent properties.
10.1002-adem.202401957	-1		The growing efficiency demands in aerospace components, such as heat exchangers, require the production of more and more complex copper parts that offer both high strength and electrical conductivity. The CuCrZr alloy, widely used in this field, can be further enhanced by incorporating ceramic nanoparticles to increase strength with minimal impact on conductivity. Powders-based additive manufacturing using laser (PBF-LB/M), provides the flexibility to produce customized 3D components while enabling versatile alloy designs. A key challenge in manufacturing oxide-dispersion-strengthened copper alloys (Cu-ODS) is the availability of appropriate powder feedstock. This study examines a process chain to produce dispersoid-strengthened CuCr1Zr using in situ alloying with metalized nanoceramics. CuCr1Zr powder is created through gas atomization, while copper-plated alumina (Cu-Al2O3) nanoparticles are prepared using an organic surface activation method. Additive manufacturing is then conducted using green and red laser systems via PBF-LB/M, followed by heat treatment at 480 degrees C for 2 h . The results show excellent densification and surface quality in printed samples, both with and without nanoparticle reinforcement. Additionally, it is found that lower levels of organic activation improve the relative density of the printed components, underscoring the need to optimize this process step for enhanced material properties.
10.1002-adem.202402218	-1		Herein, the strength and hardness of copper-chromium-zirconium alloy are enhanced in a single pass by a severe plastic deformation (SPD) technique called the multiangular twist channel extrusion (MATE) process. In equal channel angular pressing (ECAP) and twist extrusion (TE), requisite strain and uniformity are achieved through several extrusion passes. MATE is a single-pass novel SPD technique developed by integrating TE with the ECAP followed by a direct channel zone. The deformation behavior of metal in the MATE process is elucidated through experimental and microstructural studies conducted in each zone. The MATE-processed Cu-Cr-Zr alloy achieves a hardness of 184.4 HV and a tensile strength of 645.2 MPa, reflecting an increase of 80.43% and 69.7%, respectively, relative to the annealed condition. The electrical conductivity of the MATE-processed Cu-Cr-Zr alloy decreases to 74.29% International Annealed Copper Standard. The electron backscatter diffraction investigation reveals an average grain size of 2.8 mu m, with 61% comprising low-angle grain boundaries, while the calculated dislocation density, from X-ray diffraction analysis, is 3.93 x 1014 m-2. The transmission electron microscopy image verifies the existence of dislocations and precipitates in the Cu-Cr-Zr alloy. The experimental and microstructural findings in each zone have aligned effectively.
10.1002-adem.202402267	14	strength; properties; conductivity; electrical; mechanical; cu-; grain; mpa; electrical conductivity; aging; precipitation; phase; mechanical properties; tensile; phases	Cu-based self-lubricating composites have excellent mechanical properties and enhanced friction characteristics, rendering them ideal for aerospace wear parts. However, the significant mismatch in coefficients of thermal expansion (CTE) between them and counterparts, typically steel, would limit their widespread application. To address this issue, Ni50Fe powders with a low CTE are incorporated into Cu15Ni8Sn-MoS2 composites via mixing and hot-pressed sintering, resulting in Cu15Ni8Sn-Ni50Fe-MoS2 composites. The addition of Ni50Fe significantly reduces the CTE of the composites. When added in moderation, Ni50Fe can enhance the mechanical properties and wear resistance, despite a slight degradation in lubricity. The variations in mechanical and friction properties of the composites are attributed to the reaction of Cu and Fe with MoS2 and the change of matrix composition. The composite containing 40 vol% Ni50Fe (N40) has the best comprehensive performance. Compared to the Cu15Ni8Sn-MoS2 composite, the CTE of N40 is reduced by 13.7%, along with increases in hardness (5.2%), transverse rupture strength (19.1%), radial crushing strength (11.3%), and a reduction in wear rate (8.8%), although its friction coefficient increases by 15.4%.
10.1002-adem.202402412	-1		Pure copper has a very low strength of not more than 20 MPa. Nevertheless, its mechanical properties can be enhanced by (micro)alloying, additions of strengthening particles/elements, or imparting structure modifications/grain refinement via (severe) shear strain. The presented study proposes a way of strengthening commercially pure copper by combining 5 wt% addition of La2O3 particles and deformation processing. The composite is vacuum induction cast and subsequently processed by the equal channel angular pressing (ECAP) severe plastic deformation method. Single-pass ECAP through a die with 110 degrees angle is selected to observe the effect of La2O3 addition on the development of substructure at the beginning of plastic deformation. The results show that the addition of oxide particles not only enhances the microhardness, but also efficiently supports the development of subgrains and shear bands during deformation, which finally results in an increase in the microhardness of the composite to more than double the original copper value. Although the presence of La2O3 particles slightly decreases the electric conductivity, the subsequent ECAP processing provides the final composite with a conductivity of 97.9% IACS (International Annealed Copper Standard), as it promotes the alignment of the strengthening particles along the developed shear bands.
10.1002-adem.202500492	14	strength; properties; conductivity; electrical; mechanical; cu-; grain; mpa; electrical conductivity; aging; precipitation; phase; mechanical properties; tensile; phases	This paper presents a comprehensive investigation into the influence of manganese on the microstructural characteristics and properties of Cu-12.0Al-4.0Ni-xMn high-temperature shape memory alloys. The study reveals that the matrix structure of these alloys is primarily composed of both 18R and 2H martensitic phases, with a notable increase in the proportion of the 18R phase as the Mn content rises. Notably, the addition of Mn significantly enhances the thermal stability of the Cu-12.0Al-4.0Ni alloy system. Upon examining the alloys with varying Mn contents, it is observed that when the Mn content is less than 1.5 wt%, the phase transformation temperatures exhibit considerable fluctuations during thermal cycling. In contrast, when the Mn content reaches or exceeds 1.5 wt%, the Cu-12.0Al-4.0Ni-xMn alloy demonstrates commendable thermal stability even after 50 thermal cycles. Furthermore, among the studied compositions, the Cu-12.0Al-4.0Ni-1.5Mn alloy exhibits optimal plasticity of 12.8% and shape memory effect of 6.4%.
10.1002-adem.202500633	-1		Microwave processing is an innovative and sustainable technique characterized by its unique heating properties, significant energy efficiency, shorter processing times, and environmentally friendly nature. This study aims to improve copper (Cu) powder-based metal-matrix composites (MMCs) by adding tungsten (W) powder in weight fractions of 5% to 15%, using microwave heating at 900 W and 2.45 GHz. To achieve uniform melting and heating of the Cu-based powders, microwave hybrid heating is used. A high-temperature tribometer is used to test the tribological performance of the copper metal-matrix composite (Cu-MMC) at 400 degrees C against an EN31 disc. At 400 degrees C, the Cu-MMC's worn surfaces show unique properties that result in significant variations in tribological behavior. The coefficient of friction increases minimally from 0.593 to 0.63 at this temperature. Pure copper exhibits a significant increase in weight loss at 400 degrees C, the composite reinforced with 15%W (Cu+15%W) demonstrates superior wear resistance under the same conditions. The development of intermetallic phases and the uniform dispersion of W particles significantly enhance the mechanical characteristics of the composites. 15% W reinforcement enhanced the composite's Vickers microhardness to 2.38 times that of pure microwave-processed copper, indicating its superior mechanical performance.
10.1002-adem.202500841	14	strength; properties; conductivity; electrical; mechanical; cu-; grain; mpa; electrical conductivity; aging; precipitation; phase; mechanical properties; tensile; phases	Cu-Ti alloy has excellent mechanical properties and high-temperature stability. It is an ultra-high-strength, environmentally friendly copper alloy that serves as a substitute for Cu-Be alloys. However, high-strength copper titanium alloy (strength > 1000 MPa) generally has low conductivity (<20% international annealed copper standard (IACS)) and poor elongation (about 6%). This study utilizes an integrated approach of aging, cold rolling, and subsequent aging to develop a Cu-3Ti alloy with a balanced combination of high strength, superior electrical conductivity, and enhanced plasticity. The alloy achieves high strength, with a tensile strength of 1043 MPa and a yield strength of 1017 MPa, while also exhibiting excellent electrical conductivity (24.13%IACS) and elongation (10%). Transmission electron microscopy analysis demonstrates that the abundant presence of beta '-Cu4Ti precipitation phases, combined with dense dislocation networks in the Cu-3Ti alloy matrix, plays a crucial role in enhancing its mechanical performance. The emergence of beta '-Cu4Ti phases induces Ti depletion in the copper solid solution, thereby suppressing lattice distortion-induced carrier scattering. The dominant strengthening mechanism is identified as Orowan bypassing mechanism. Through thermodynamic analysis, a modified Johnson-Mehl-Avrami-Kolmogorov model is formulated to describe precipitation kinetics and an activation energy of Q = 60 kJ mol(-1) determined via Arrhenius equation fitting.
10.1002-adem.202500866	14	strength; properties; conductivity; electrical; mechanical; cu-; grain; mpa; electrical conductivity; aging; precipitation; phase; mechanical properties; tensile; phases	Multiprincipal element alloys (MPEAs) exhibit a wide range of microstructures and mechanical properties, depending on composition and processing. In this study, the impact of Cu addition on the microstructure and mechanical performance of MoNbTi MPEAs is investigated. Cu plays a dual role, promoting the formation of strengthening intermetallic phases while, at higher concentrations, potentially increasing brittleness. It also influences diffusion kinetics and phase transformation, leading to dendritic refinement and the formation of Cu-Ti intermetallics. Phase diagram simulations predict the behavior of CuxMoNbTi alloys with varying Cu content (x = 0, 0.25, 0.5, 1.0, and 2.0). The alloys are synthesized by arc casting and analyzed using X-ray diffraction, scanning electron microscopy, and energy dispersive spectroscopy. Mechanical properties are evaluated through Vickers hardness and compressive testing. The results show that Cu enhances densification and refines the dendritic structure, increasing hardness and strength . However, excessive Cu content leads to an increased fraction of Cu-rich intermetallics. Hardness ranges from 515 +/- 54 HV to 614 +/- 47 HV, while UTS peaks at approximate to 2000 +/- 80 MPa for Cu0.5MoNbTi, nearly doubling that of MoNbTi. The well-distributed precipitate network in Cu0.5MoNbTi enables effective plastic deformation by reducing stress concentrations and delaying crack formation. Cu tailors MPEA microstructures, optimizing properties for applications.
10.1002-adem.202500935	14	strength; properties; conductivity; electrical; mechanical; cu-; grain; mpa; electrical conductivity; aging; precipitation; phase; mechanical properties; tensile; phases	This study investigates the crack initiation and damage behavior of C17200 beryllium copper alloy under very high cycle fatigue (VHCF) conditions. Ultrasonic fatigue tests (20 kHz) demonstrate fatigue lives spanning 3.05 x 106 cycles at 400 MPa to 1 x 1010 cycles at 240 MPa, with a distinct transition to internal crack initiation beyond 107 cycles. Fractographic analysis via field emission scanning electron microscopy identifies grain boundaries (GBs) and persistent slip bands as critical damage sites. Crystal plasticity finite element method simulations reveal that stress concentrations at GBs and accumulated plastic shear strain localized along 45 degrees slip systems are the primary drivers of crack initiation and propagation, respectively. These results establish that GBs stress concentration induced by adjacent grain misorientation and preferential activation of 45 degrees slip systems fundamentally govern VHCF failure in C17200 alloy.
10.1002-adem.202501215	15	aging; strength; conductivity; electrical conductivity; electrical; mpa; treatment; strengthening; degrees; cu-; cold; precipitation; tensile strength; tensile; iacs	With the rapid development of high-tech and manufacturing industries, higher mechanical properties and electrical conductivity requirements are required. Cu-5Ag, Cu-10Ag, Cu-5Ag-0.5Cr, and Cu-10Ag-0.5Cr (at%) alloys are fabricated and investigated to achieve high strength and electrical conductivity. After solution treatment at 750 degrees C for 4 h, hot rolling by 60% at 700 degrees C, cold rolling by 50%, first intermediate annealing at 350 degrees C for 10 min, cold rolling by 50%, second intermediate annealing at 350 degrees C for 10 min, cold rolling by 60%, the Cu-10Ag-0.5Cr alloy exhibits an ultimate tensile strength of 687 MPa and an electrical conductivity of 74% international annealed copper standard. The high strength is attributed to work hardening, fiber strengthening, and precipitation strengthening. The primary Cr particles slightly reduce the mechanical properties, while the nanoscale Cr precipitates contribute to precipitation strengthening. These findings are meaningful to developing high-strength and high-conductivity copper-silver alloys.
10.1002-adem.202501334	14	strength; properties; conductivity; electrical; mechanical; cu-; grain; mpa; electrical conductivity; aging; precipitation; phase; mechanical properties; tensile; phases	Application of electromagnetic stirring (EMS) during solidification represents a promising approach to tailoring the microstructure and performance of high-strength conductive alloys. In this study, the effects of EMS on the as-cast microstructure, mechanical strength, and electrical conductivity of Cu-25%Ag (wt%) alloy wires are systematically investigated. Experimental results demonstrate that EMS effectively refined the grain structure, transitioning columnar dendritic growth to equiaxed dendritic morphology. This microstructural modification led to a significant enhancement in mechanical properties, with the ultimate tensile strength increasing by approximate to 50 MPa compared to conventionally solidified wires. However, the electrical conductivity exhibited a marginal reduction of 2% International Annealed Copper Standard, attributed to intensified lattice scattering induced by grain boundary proliferation. The underlying mechanisms governing the strength-conductivity trade-off are elucidated through microstructural characterization and phase interaction analysis. These findings provide critical insights into optimizing electromagnetic processing parameters for balancing mechanical and electrical performance in Cu-Ag-based conductor alloys.
10.1002-adem.202501873	14	strength; properties; conductivity; electrical; mechanical; cu-; grain; mpa; electrical conductivity; aging; precipitation; phase; mechanical properties; tensile; phases	This study focuses on the optimization of comprehensive mechanical and electrical properties in manufacturing high-performance Cu-15Ni-8Sn alloy strips through a processing route combining cryorolling and subsequent aging. Test results show that the alloy exhibits remarkable mechanical and electrical properties under the conditions of 70% cryorolling and aging at 350 degrees C for 4 h, with yield and tensile strengths reaching 1264 and 1330 MPa, respectively, coupled with 9.0% IACS. These enhanced characteristics result from the synergistic effect of high-density dislocations, deformation twins, and the uniform distribution of nanoscale coherent DO22 ordered phases formed during aging within the alloy. This work not only elucidates the coupling strengthening mechanism between multiscale defects and precipitates, but also provides an optimized approach for improving the comprehensive property of high-performance Cu-15Ni-8Sn alloy.
10.1002-adem.202501886	-1		High-lead copper alloy exhibits excellent lubrication property and finds application in copper-steel bimetallic. However, lead tends to segregate at grain boundaries, which impairs mechanical and tribological properties. To resolve this, this study employs the rare-earth Ce-characterized by high chemical activity and strong grain boundary segregation tendency-as a modifier. Copper-steel bimetallic materials are prepared using melting-casting process, and the influence of Ce on the microstructure and tribological properties of the bimetallic materials is investigated. The mechanisms for inhibiting lead segregation and improving tribological properties are revealed. Results show that adding Ce can refine particles and suppress the segregation of Pb. With increasing the content of Ce, the particle size of Pb first decreases and then increases, while the mechanical and tribological properties of the composite initially improve and then deteriorate. During the melting-casting process, the refractory CePb3 phase, formed by Ce and Pb, serves as heterogeneous nucleation sites that refine the matrix's grain structure by providing additional nucleation points. This process divides more Pb melt pools, preventing coalescence and segregation. The dispersed lead enhances the stability of the Pb lubrication film, thereby improving the tribological performance.
10.1002-adfm.200901732	2	corrosion; surface; film; electrochemical; films; spectroscopy; layer; current; solution; potential; resistance; composition; x-ray; ions; showed	Nanocrystalline 3 mu m thick Cu1-xNix (0.45 <= x <= 0.87) films are electrodeposited galvanostatically onto Cu/Ti/Si (100) substrates, from a citrate- and sulphate-based bath containing sodium lauryl sulphate and saccharine as additives. The films exhibit large values of reduced Young's modulus (173 < E-r < 192 GPa) and hardness (6.4 < H < 8.2 GPa), both of which can be tailored by varying the alloy composition. The outstanding mechanical properties of these metallic films can be ascribed to their nanocrystalline nature as evidenced by X-ray diffraction, transmission electron microscopy, and atomic force microscopy along with the occurrence of stacking faults and the concomitant formation of intragranular nanotwins during film growth . Due to their nanocrystalline character, these films also show very low surface roughness (root mean square deviation of around 2 nm). Furthermore, tunable magnetic properties, including a transition from paramagnetic to ferromagnetic, behavior, are observed when the Ni percentage is increased. This combination of properties, together with the simplicity of the fabrication method, makes this system attractive for widespread technological applications, including hard metallic coatings or magnetic micro/nano-electromechanical devices.
10.1002-adfm.201103019	-1		Copper-based shape memory alloys (SMAs) exhibit excellent shape memory properties in single crystalline form. However, when they are polycrystalline, their shape memory properties are severely compromised by brittle fracture arising from transformation strain incompatibility at grain boundaries and triple junctions. Oligocrystalline shape memory alloys (oSMAs) are microstructurally designed SMA structures in which the total surface area exceeds the total grain boundary area, and triple junctions can even be completely absent. Here it is shown how an oligocrystalline structure provides a means of achieving single crystal-like SMA properties without being limited by constraints of single crystal processing. Additionally, the formation of oSMAs typically involves the reduction of the size scale of specimens, and sample size effects begin to emerge. Recent findings on a size effect on the martensitic transformation in oSMAs are compared and a new regime of heat transfer associated with the transformation heat evolution in these alloys is discussed. New results on unassisted two-way shape memory and the effect of loading rate in oSMAs are also reported.
10.1002-adfm.202413332	-1		Overcoming the strength-ductility trade-off in metals and alloys entails the optimization of the compositions and dedicated microstructural design, which remains experimentally laborious and challenging. Here, a combinatorial method is devised to construct a Cu-Ti alloy library encompassing diverse compositions, microstructures, and mechanical properties, allowing to efficiently identify a copper alloy with an unprecedented yield strength of 3.8 GPa and high deformability. The exceptional properties are attributed to a crystal-glass nano-heterostructure (CGNH) consisting of nanograins, nano twins, and glassy phases. Ultrahigh strength stems from the extreme strengthening of structural-unit refinement and the avoidance of softening caused by grain-boundary sliding through the inclusion of glassy phases between nanograins. Remarkable deformability is associated with the activation of homogeneous flow in nanosized glassy phases, complemented by coordinated nanocrystal rotation. The CGNH architecture offers a potent route to overcome the trade-off between alloy strength and deformability. A modular combinatorial method is developed to create a Cu-Ti alloy library with diverse microstructures and properties. This allows for the efficient identification of a crystal-glass nano-heterostructure (CGNH) comprising nanograins, nanotwins, and glassy phases, achieving exceptional mechanical properties. The CGNH overcomes the alloy strength-deformability trade-off through extreme refinement strengthening, activation of homogeneous flow in glassy phases, and avoidance of grain-boundary sliding. image
10.1002-adhm.202501303	14	strength; properties; conductivity; electrical; mechanical; cu-; grain; mpa; electrical conductivity; aging; precipitation; phase; mechanical properties; tensile; phases	This study introduces an innovative design and application of a nitrogen-interstitially strengthened Cu-Fe-Zn alloy bioactive dressing, which combines intrinsic bioactivity with electromagnetic stimulation to significantly accelerate wound healing. Interstitial nitrogen solid-solution Cu-Fe-Zn alloys were fabricated by integrating a low-oxygen controlled powder sintering process (N2(10%)/Ar (90%) atmosphere). Subsequent cold drawing generated ultrafine alloy wires (0.04 +/- 0.005 mm) with a tensile strength of 1120 MPa, representing a 20.37% enhancement compared with conventional approaches. Utilizing an intelligent jacquard textile system, these Cu-Fe-Zn alloy wires and cotton yarn were woven into coaxial circular dressings tailored to wound morphology, allowing controlled directional current flow while exhibiting excellent biocompatibility and antibacterial properties. A customized electromagnetic coupling system, consisting of an electromagnetic field generator and Helmholtz coils, was developed. Integration with bioactive dressings resulted in a precise, multifunctional therapeutic platform. Electromagnetic stimulation achieved dual therapeutic outcomes: (1) activating the VEGF/p38-HSP27 signaling pathway, significantly enhancing angiogenesis (2.1-fold compared with controls) and promoting M2 macrophage polarization (+25.6%), thereby accelerating tissue regeneration; and (2) inhibiting the IL-17/NF-kappa B signaling axis, reducing TNF-alpha expression by 68%, thus effectively suppressing inflammation. This study offers essential technical insights for developing next-generation intelligent electromagnetic wound healing systems with substantial clinical potential.
10.1002-adma.200601472	-1		Simultaneous increase of the ductility and strength of bulk ultra-fine-grained (UFG) Cu is achieved by introducing large amounts of deformation twins and high-angle grain boundaries via cryodrawing and cryorolling (red plots and image). Bulk UFG materials usually have high strength but disappointingly low ductility. Most previous attempts to enhance the ductility of single-phased UFG materials sacrificed their yield strength . This work provides a new approach for increasing ductility without sacrificing strength .
10.1002-admi.202000921	-1		The improvement of many applications in the fields of catalysis, surface and coatings technology, biomedicine, and fuel cells depends on the advances in nanoalloy research . Here, a structural and thermal study of nanostructures of Cu-Ta particles produced using a high-current pulsed arc (HCPA) is presented. Structural analysis performed utilizing electron microscopy and X-ray spectroscopy shows the formation of distinctive single crystals with grain sizes larger than 100 nm. Notably, these grains exhibit evidence of a variation of the characteristic immiscibility of Cu and Ta, as found in the bulk scale. The nonequilibrium HCPA method appears to offer a way to surpass miscibility barriers in bimetallic alloys. This technique also allows the synthesis of oxygen-free powders in sufficient quantities to perform a variety of characterization measurements. The detailed Cu-Ta alloy crystals and oxidation temperature in a high purity oxygen atmosphere and the stability at high temperatures in argon are analyzed.
10.1002-admi.202001673	-1		Tribochemical reactions in many applications determine the performance and lifetime of individual parts or entire engineering systems. The underlying processes are however not yet fully understood. Here, the tribological properties of copper and its oxides are investigated under mild tribological loading and for dry sliding. The oxides represent the late stages of a copper-sapphire tribo-contact, once the whole copper surface is covered with an oxide. For this purpose, high-purity copper, thermally-oxidized and sintered Cu2O and CuO samples are tribologically loaded and eventually formed wear particles analyzed. The tribological behavior of the oxides is found to be beneficial for a reduction of the coefficient of friction (COF), mainly due to an increase in hardness. The results reveal tribochemical reactions when copper oxides are present, irrespective of whether they form during sliding or are existent from the beginning. Most strikingly, a reduction of copper oxide to metallic copper is observed in X-ray photoelectron spectroscopy measurements. A more accurate understanding of tribo-oxidation will allow for manufacturing well-defined surfaces with enhanced tribological properties. This paves the way for extending the lifetime of contacts evincing tribo-oxidation.
10.1002-admi.202500215	14	strength; properties; conductivity; electrical; mechanical; cu-; grain; mpa; electrical conductivity; aging; precipitation; phase; mechanical properties; tensile; phases	The oxidation of copper significantly restricts its widespread industrial applications. Traditional methods, such as alloying and anti-corrosion coatings, often compromise copper's electrical and thermal conductivity. Molecular passivation technology has emerged as a promising solution, enhancing copper's anti-corrosion properties without degrading its intrinsic physical characteristics. However, the enhancement of copper's anti-corrosion properties through molecular passivation is far from satisfactory. Herein, allyl mercaptan is employed as a molecular passivation monomer to investigate its anti-corrosion performance. It is demonstrated that allyl mercaptan can coordinate and polymerize on copper surfaces under mild conditions, forming polymeric passivation layers. The modified copper foil (Cu-AM) exhibits a corrosion-inhibiting efficiency of 99.65%. Density functional theory (DFT) calculations indicate that the coordination of allyl mercaptan on various copper crystal planes is spontaneous, with the dissociation adsorption energy ranking as Cu(100) > Cu(110) > Cu(111). Anti-corrosion experiments on single-crystal copper foils further corroborate these findings, showing that Cu(100)-AM achieves the highest corrosion-inhibiting efficiency of 99.91%.
10.1002-admi.202500533	2	corrosion; surface; film; electrochemical; films; spectroscopy; layer; current; solution; potential; resistance; composition; x-ray; ions; showed	This paper assesses whether copper surfaces retain their anti-viral efficacy, or whether this property is altered by exposure to the cleaning solutions of glutaraldehyde or NaClO, when used in high-touch surfaces that are regularly touched by many people. The results obtained show that copper has a virus titer of 50% after 30 and 60 min of exposure, but for Cu-30Ni, 50% is not reached until 70 and 80 min in artificial sweat after cleaning. Cu-30Ni has more effective resistance to tarnishing. Copper and nickel ions are released from Cu and Cu-30Ni samples in NaClO and glutaraldehyde solutions. A brief exposure to disinfectant solutions causes corrosion product formation on both Cu and Cu-30Ni surfaces, primarily composed of Cu2O. In contrast, CuO and Cu(OH)2 are the primary compounds that contribute to creating a thicker film formed as exposure time is increased. Phases containing chlorine are present in the corrosion product composition. This research introduces a new understanding of how copper and Cu-30Ni alloys respond to disinfectant solutions and humid air. The Cu-30Ni alloy offers superior corrosion resistance, retaining a shiny appearance, but simultaneously reflects an increased viral inactivation time due to a more stable oxide layer compared to pure copper.
10.1002-bbpc.19981020941	-1		The distribution ratio of the component elements between the liquid Cu-Zn-Fe or Cu-Ni-Fe alloy and the FeOx-SiO2-CaO or MgO-saturated FeOx-SiO2-CaO slag was evaluated thermodynamically based on the activity coefficients of the alloy components determined using a transpiration method and a double Knudsen cell-mass spectrometer.
10.1002-celc.201402350	2	corrosion; surface; film; electrochemical; films; spectroscopy; layer; current; solution; potential; resistance; composition; x-ray; ions; showed	The electrodeposition of Cu-Zn and Zn-Sn films as well as free-standing nanowires from ionic liquids 1-ethyl-3-methylimidazolium trifluoromethylsulfonate and 1-butyl-1-methylpyrrolidinium trifluoromethylsulfonate is reported. The nanowire arrays were obtained by using polycarbonate membranes. The study includes cyclic voltammetry, chronoamperometry, X-ray diffraction, and scanning electron microscopy-energy-dispersive X-ray analyses. The results show that the morphology and the composition of the electrodeposited Cu-Zn alloys are dependent on the deposition potential. Free-standing Cu-Zn nanowires with average diameters and lengths of approximately 100 nm and 5 mm, respectively, were prepared. The morphology of Zn-Sn deposits shows coarse Zn particles on a Sn-rich layer, indicating the formation of Zn/Sn co-deposits. The XRD results reveal the co-deposition of Zn-Sn films. Zn-Sn nanowires with average diameters of approximately 100 nm and lengths of 5 mm were synthesized. Free-standing Zn-Sn nanowires with different lengths and a diameter of approximately 200 nm were also synthesized.
10.1002-celc.202100218	2	corrosion; surface; film; electrochemical; films; spectroscopy; layer; current; solution; potential; resistance; composition; x-ray; ions; showed	A mixed ligand copper(II) complex, namely, [Cu(BPy)(Gly)Cl]2H(2)O (CuC) (BPy=2,2 '-bipyridine and Gly=glycine), was synthesized and characterized. The synthesized CuC complex was tested as inhibitor to effectively mitigate the corrosion of copper in alkaline solutions using the linear sweep voltammetry (LSV) and linear polarization resistance (LPR) techniques. For the sake of comparison, such two D.C. electrochemical techniques were also applied to the Cu/OH- interface in the presence of the two studied free ligands, namely, BPy and Gly. The results showed that the three studied compounds acted as mixed-type inhibitors, with CuC being the most efficacious one. The adsorption of the inhibitor is confirmed from X-ray photoelectron spectroscopy (XPS) profiles by the appearance of organic chlorine as well as pyridine and amine nitrogen bonds. Based on XPS data, it was presumed that the corrosion inhibitor stimulates the formation of Cu2CO3(OH)(2) species at the electrode surface since, in the case of a corroded reference sample (in absence of inhibitors), its proportion is trivial. The reactivity of the isolated inhibitors was analyzed by computing several quantum chemical parameters based on the density functional theory (DFT). A good correlation was found between these parameters and the anticorrosive performance. Additionally, Monte Carlo simulation studies were applied to find the best configurational space of ligands and their complex on the Cu(111) surface.
10.1002-crat.201200116	-1		The current paper focuses on the solidification characteristics of a Cu-Sb eutectic alloy in its different liquid states. Liquid alloy resistivity-temperature patterns suggest an irreversible temperature-induced liquid-liquid structure transition (TI-LLST), and a reversible TI-LLST occurred during the heating-cooling runs. A set of solidification experiments was conducted based on the results. The irreversible TI-LLST caused an enhanced solidification undercooling, increased solidification rate, refined regular eutectic morphologies, and absence of a pre-eutectic Cu2Sb phase. The reversible TI-LLST resulted in different phase compositions and eutectic structures. The mechanisms behind these transitions are also briefly discussed.
10.1002-eqe.2659	3	sma; shape; shape memory; memory; smas; superelastic; bars; damping; cu-al-mn; mechanical; bending; applications; numerical; sma bars; material	Shaking table tests are performed on a one-bay one-story steel frame with superelastic Cu-Al-Mn shape memory alloy (SMA) tension braces. The frame is subjected to a series of scaled ground motions recorded during the 1995 Kobe earthquake, Japan. The test results demonstrate that the SMA braces are effective to prevent residual deformations and pinching. It is also shown that the time history responses observed from the shaking table tests agree well with the numerical predictions using a rate-independent piecewise-linear constitutive model calibrated to the quasi-static component tests of the SMA braces. This suggests that the loading rate dependence of Cu-Al-Mn SMAs as well as the modeling error due to the piecewise linear approximation can be neglected in capturing the global response of the steel frame. Numerical simulations under a suite of near-fault ground motion records are further performed using the calibrated analytical models to demonstrate the effectiveness of the SMA braces when the variability of near-fault ground motions is taken into account. A stopper, or a deformation restraining device, is also proposed to prevent premature fracture of SMA bars in unexpectedly large ground motions while keeping the self-centering capability in moderate to large ground motions. The effectiveness of the stopper is also demonstrated in the quasi-static component and shaking table tests. Copyright (c) 2015 John Wiley & Sons, Ltd.
10.1002-jemt.20877	-1		The irradiation effects of thinning a sample of a Cu-Zn-Al shape memory alloy to electron transparency by a Ga+ focused ion beam were investigated. This thinning method was compared with conventional electropolishing and Ar+ ion milling. No implanted Ga was detected but surface FCC precipitation was found as a result of the focused ion beam sample preparation. Decreasing the irradiation dose by lowering the energy and current of the Ga+ ions did not lead to a complete disappearance of the FCC structure. The latter could only be removed after gentle Ar+ ion milling of the sample. It was further concluded that the precipitation of the FCC is independent of the crystallographic orientation of the surface. Microsc. Res. Tech . 74:84-91, 2011. (C) 2010 Wiley-Liss, Inc.
10.1002-jrs.6453	2	corrosion; surface; film; electrochemical; films; spectroscopy; layer; current; solution; potential; resistance; composition; x-ray; ions; showed	This work is the first archaeometric investigation on copper and iron wastes from the Phoenician site of Motya (Sicily, Italy), dating back to the 8th to the 4th century BC. The samples were analyzed through micro-Raman Spectroscopy (mu-RS), Optical Microscopy (OM), Scanning Electron Microscope-Energy-Dispersive X-ray Spectroscopy (SEM-EDS), High-Resolution Field Emission Scanning Electron Microscopy (HR-FESEM), and Electron Micro-Probe Analysis (EMPA). Micro-Raman techinique permitted to identify both primary phases, for example, calchopyrite, and secondary products such as cuprite and copper thrihydroxychlorides in the Cu-slags and goethite in the Fe-slags. SEM and HR-FESEM imaging showed the occurrence of inhomogeneous microstructures in the Cu- and Fe-slags due to elements segregation, solidification, and corrosion. EMPA data revealed that the archaeometallurgical wastes from Motya can be differentiated on the basis of their chemical compositions. These preliminary results showed different typologies of by-products, such as base metals speiss, copper slags from smelting sulfide ore with matte, and iron smelting and smithing slags, suggesting different stages of copper and iron productions.
10.1002-kin.21521	-1		The crystallization kinetics of (Cu48Zr48Al4)(100-)Nd-x(x) (x = 0, 2 at%) bulk metallic glasses in nonisothermal and isothermal conditions were studied by differential scanning calorimetry and X-ray diffraction (XRD). XRD analysis shows that the crystallization product Cu10Zr7 changes to Cu10Zr7 and Cu2Nd with Nd presence in nonisothermal and isothermal conditions. Crystallization activation energy was calculated in nonisothermal conditions using Kissinger and Ozawa methods and in isothermal conditions using Arrhenius model. The results show that the activation energy harbored by (Cu48Zr48Al4)(98)Nd-2 expresses larger value compared with Cu48Zr48Al4, which indicate that the energy barrier for crystallization has enhanced along the Nd addition. The Johnson-Mehl-Avrami model was employed for analyzing the crystallization kinetics in isothermal condition. The Avrami exponent n for Cu48Zr48Al4 is more than 2.5, demonstrating that the crystallization is mainly governed by diffusion-controlled three-dimensional growth with increasing nucleation rate. Comparably, the Avrami exponent n for (Cu48Zr48Al4)(98)Nd-2 is 1.5 n < 2.5, suggesting that the crystallization is mainly determined by diffusion-controlled three-dimensional growth with decreasing nucleation rate. The evident enhancement in crystallization activation energy based on Nd addition is rationally made up of an influential factor commonly harbored on the enhanced glass forming ability for the rare-earth comprising Cu-Zr-Al metallic glasses.
10.1002-ls.1734	17	wear; composites; coating; friction; composite; coatings; surface; tribological; properties; wear resistance; resistance; powder; sliding; matrix; wear rate	A strategy involving the use the rare-earth compound LaF3 with good lubrication and stability properties as a filler in the preparation of Cu-based composites was proposed to solve the problem of poor wear resistance in Pb-free Cu-Bi materials. The influence and regulatory mechanism of LaF3 content on the mechanical and tribological properties of these composites were studied. The results indicate that LaF3 has a good refining effect on Cu alloy grains, and LaF3 and Bi are distributed in a network along the grain boundaries of the Cu alloy in the material. As the LaF3 content increases, the mechanical properties and friction coefficient of the composite gradually decrease, and the wear rate first declines and then increases. The wear resistance of Cu-Bi composite containing LaF3 mainly depends on the mechanical support provided by the matrix. When the LaF3 content is higher than 6%, the composite strength is extremely low, and the increase in lubricant content at the friction interface does not play a decisive role in the material wear behaviour. The material wear rate increases with the increase in LaF3 content. Therefore, using 6% LaF3 is recommended to improve the wear resistance of the material and maintain a balance among its mechanical properties, antifriction and wear resistance.
10.1002-maco.200503866	2	corrosion; surface; film; electrochemical; films; spectroscopy; layer; current; solution; potential; resistance; composition; x-ray; ions; showed	The electrochemical behavior of pure copper has been studied in aqueous environments using linear polarization and electrochemical impedance spectroscopy (EIS) techniques as a function of immersion time. The effect of pollutants (like chloride, sulfide and ammonium ions) on the nature of films formed on the copper surface has been studied. All the surfaces revealed the presence of a porous oxide layer. The corrosion resistance decreased with increasing amount,of chloride ions. The addition of Na2S in the environments in the absence of any chloride species was beneficial for corrosion resistance. EIS data suggested that the capacitance of the films formed in chloride environments was higher. The surfaces obtained in presence of chloride ions were relatively rough and deeply attacked. The total impedance decreased after 432 h of immersion in solutions possessing chloride ions. The damaging role of chloride ions and the relatively less severe effect of sulfide ions were noted.
10.1002-maco.200704054	-1		Zinc-containing copper alloys, the so-called alpha + beta brasses, are commonly used in contact with potable water. These materials are alloyed with lead to improve machinability. In wrought special brass alloys, reducing the content of this alloying element or replacing it with alternative alloying additions may give rise to a new type of machinable copper alloys which differ from the original alloys by their contents of other modifier elements such as Si (or possibly, Mg, Bi, and P). These alloys have a very low content of lead required for the break-up of chips during machining. Even though these types of brass exhibit a very good machinability, the effects of their chemical composition on the resistance of the alloy to corrosion cracking have not yet been given sufficient attention. This paper aims to present an assessment of three new types of machinable copper alloys regarding their susceptibility to stress corrosion cracking, in comparison to that of the lead-alloyed variety, in 0.05 M NaCl, NaNO2, and Na2SO4 solutions. The slow strain rate test has been used for this purpose, and its results were correlated with metallographic evaluation of the number and depth of the cracks observed on the test specimen surfaces on completion of the test.
10.1002-maco.200805068	2	corrosion; surface; film; electrochemical; films; spectroscopy; layer; current; solution; potential; resistance; composition; x-ray; ions; showed	Analytical and electrochemical techniques were used to characterize the alteration of Tunisian ethnographic copper artefacts. Analytical results confirmed the existence of the bulk material in both objects constituting the ethnographic set. The bulk material was identified as a copper alloy with about 11% carbon content. The material was plated with a tin-based coating prior to use. Alteration characterization showed that corrosion is more severe at the bottom of the 'Kiskes' where the object was submitted to the hot steam. EN results reflected the interaction of the aggressive anion (Cl-) with the passive layer and the condensation of cation vacancies. Three anodic peaks were evidenced in the polarization curve corresponding to the oxidation of Sn(II), Cu(O) and Cu(I). A hysteresis loop was detected in the reversed scan confirming surface pitting.
10.1002-maco.200905240	2	corrosion; surface; film; electrochemical; films; spectroscopy; layer; current; solution; potential; resistance; composition; x-ray; ions; showed	Corrosion performance of copper and brass coupons during 15 month exposure in atmosphere, underground and splash zone conditions was undertaken at Khaleej Mardumah test site located in the industrial/coastal city of Jubail along the Arabian Gulf coast, Saudi Arabia. The environmental indicators such as soil, groundwater, seawater, and air particulate samples were assessed. The exposed corrosion coupons were examined by scanning electron microscopy (SEM) coupled with energy dispersive X-ray spectroscopy (EDS), X-ray diffraction (XRD) and X-ray fluorescence (XRF) to identify the corrosion products and study their surface morphology. Corrosion rate was determined by weight loss method. The experimental results indicated that a high degree of variation in temperature and humidity in this region combined with high chloride and sulfate concentrations was primarily responsible for the corrosion of copper and brass at Khaleej Mardumah test site. Underground environment was the most corrosive to both copper and brass coupons studied, followed by splash zone. Corrosion rates were found to range from 4.29 to 3.0.84 mu m/y for copper and from 2.47 to 29.33 mu m/y for brass. Corrosion rates of copper and brass obtained in this study are also compared with those reported for other locations worldwide.
10.1002-maco.200905345	2	corrosion; surface; film; electrochemical; films; spectroscopy; layer; current; solution; potential; resistance; composition; x-ray; ions; showed	In this article, the corrosion behavior of Cu-Fe and Cu-Al-Fe was studied in H2SO4 solutions in the absence and presence of different concentrations of some inorganic additives, Na2MoO4, K2Cr2O7, KIO3, and Na2B4O7. The techniques of measurements used were open-circuit potential, potentiodynamic polarization, and electrochemical impedance spectroscopy. The polarization measurements indicated that the corrosion current, I-corn of Cu-Fe is less than that of Cu-Al-Fe. The investigated additives in H2SO4 shifted E-corr to more positive values and increases I-corn Impedance measurements indicated that Nyquist plots for Cu-Fe may be regarded as a semi-circle in early stages of immersion and tends to be a part of semi-circle with elapse of time and a well-defined inductive loop appears. In case of Cu-Al-Fe, the Nyquist plots tends to be semi-circle or depressed semi-circle. The values of R-p for Cu-Fe are higher than those for Cu-Al-Fe. On the other hand, the values of C-dl for Cu-Fe are lower than those obtained for Cu-Al-Fe. The presence of these additives in H2SO4 solutions decreases the values of polarization resistance (Rp) and increases the values of corrosion current density (I-corr) and capacitance of double layer (C-dl).
10.1002-maco.201608856	2	corrosion; surface; film; electrochemical; films; spectroscopy; layer; current; solution; potential; resistance; composition; x-ray; ions; showed	The corrosion behavior of tin bronze alloy equivalent to a Punic one was investigated in aqueous 0.5M chloride electrolyte using potentiodynamic measurements. The electrochemical results showed selective dissolution of the major alloy component reflecting a decuprification process. FTIR characterization of the patina anodic layers showed the presence of various dehydrated and hydrated tin compounds with a few copper species suggesting the patina type I formation on the Cu10Sn bronze alloy. A kinetic model for the Cu10Sn bronze alloy dissolution in the chloride solution was developed. The reaction order with respect to chloride content was determined for the Cl- halide concentration domains. The low order value (about 0.22) was attributed to the Cl- adsorption intermediate step. The high reaction order value (about 2) reflected two determining steps of cuprous chloride complex formation. Two behaviors for the material were evidenced when varying the temperature. The values of the activation energy Ea, activation enthalpy H* and activation entropy S* were calculated and discussed.
10.1002-maco.201609176	2	corrosion; surface; film; electrochemical; films; spectroscopy; layer; current; solution; potential; resistance; composition; x-ray; ions; showed	This paper reports a study on four historical samples from 19th century originating from Croatia, Europe, made of silver plated and gilded copper alloys. The investigation was carried out by chromatographic, spectroscopic, and microscopic techniques. Corrosion was identified in all samples by scanning electron microscope-energy dispersive spectroscopy (SEM-EDS), although the samples were in well-preserved states. EDS has given the following average composition of elements Ag (82.99, 4.74, 6.34, and 15.54wt% in samples 1-4, respectively), Au (17.01wt% in sample 1), and Cu (0, 95.26, 93.66, and 84.46wt% in samples 1-4, respectively) for the outer layers of the samples. The exact sample elemental composition was determined by inductively coupled plasma optical emission spectroscopy (ICP-OES): 0.12, 0.22, 0.68, and 1.20wt% Ag in samples 1-4, respectively and 0.02wt% Au in sample 2, all on Cu alloys with impurities of Fe, Mn, Ni, Pb, Sb, Si, Sn, and Zn (in quantities 0.05-1.48wt%). Preliminary detection of metals was performed by thin-layer chromatography. Results of determined chemical composition were consistent with similar investigations, since silver-plated and gilded Cu alloys were the materials used in the production of similar samples through the history.
10.1002-maco.201911323	-1		The Cu-15Ni-8Sn alloy with high strength and toughness is a common bearing alloy, while it is often subjected to premature failure in service due to corrosion and wear. Therefore, the corrosion and wear behaviors of an ultra-high-strength and toughness Cu-15Ni-8Sn (wt%) alloy fabricated by hot isostatic pressing were investigated in this study. The results indicated that intergranular corrosion and pits were observed when the studied alloy was immersed into seawater for 30 days. When the Cu-15Ni-8Sn alloy slid in seawater, there was a synergistic effect between corrosion and wear. With the increase of normal load, the synergistic effect weakened initially and then enhanced the interaction between corrosion and wear changed from negative to positive, and the main wear mechanisms transferred from abrasive wear into delamination.
10.1002-maco.201911338	2	corrosion; surface; film; electrochemical; films; spectroscopy; layer; current; solution; potential; resistance; composition; x-ray; ions; showed	The corrosion behavior of synthetic Cu-Sn bronze alloys with six different Sn contents was examined through an electrochemical test and a synthetic test in a simulated corrosive medium. The mechanism of corrosion and the morphology of the corroded surfaces were characterized through field emission scanning electron microscopy equipped with energy-dispersive spectroscopy. At the corrosion potential, the corrosion behavior appears to be determined by the charge transfer step and the diffusion process. It was found that the bronze-IV (Cu-26.8Sn) specimen exhibited the best corrosion resistance, as evidenced by a low corrosion current density and a high impedance. This improvement resulted from an increase in the content of the Cu-Sn solid solution in the alloy, which was conducive to forming a relatively more protective passive film on the surface of the bronze alloy. This finding would be valuable in the anticorrosion protection of archeological artefacts after their excavation.
10.1002-maco.202012188	2	corrosion; surface; film; electrochemical; films; spectroscopy; layer; current; solution; potential; resistance; composition; x-ray; ions; showed	The corrosion behaviour of Cu-2Ti and Cu-2Zr (wt%) alloys has been assessed by open-circuit potential and electrochemical impedance spectroscopy measurements carried out in 3.5 wt% NaCl solution, at approximately neutral pH, without stirring and in contact with the air. For comparison, the electrochemical tests have also been carried out on unalloyed Cu. Electrochemical impedance results showed that Ti and Zr alloying additions significantly increased the corrosion resistance of copper, the best behaviour being observed for the Cu-2Zr alloy. This improvement may be ascribed to the formation of Ti- or Zr-enriched passive layer, which exhibits higher protective effectiveness compared with that of unalloyed Cu.
10.1002-maco.202112470	2	corrosion; surface; film; electrochemical; films; spectroscopy; layer; current; solution; potential; resistance; composition; x-ray; ions; showed	The corrosion behavior of copper, tin, and bronze CuSn14 is studied in simulated acid rain (pH 4.5) by electrochemical techniques, cyclic voltammetry and electrochemical impedance spectroscopy. The potentiodynamic formation of anodic oxide film on copper and tin is described in terms of high-field model. Cyclic voltammetry shows that dissolution of bronze is higher than of pure copper metal in acid rain. Electrochemical impedance spectroscopy data reveal that oxide films formed on copper and tin have a higher resistance and suppressed diffusion process through the surface layer than the oxide film formed on bronze CuSn14 at the same conditions.
10.1002-maco.202112748	-1		The effect of Fe/Mn content on the metallographic structure, mechanical properties, and corrosion resistance of 90/10 copper-nickel alloy using electrochemical methods, scanning electron microscope, energy dispersive spectroscopy, X-ray photoelectron spectroscopy, Tafel experiments, and electrochemical impedance spectroscopy measurements were investigated in this paper. The experimental results indicated that the tensile strength of the alloys increases from 326 to 347 MPa with the change of Fe/Mn content, the yield strength of 90/10 copper-nickel alloys is approximately 150 MPa, and the elongation of the alloys was reduced from 51% to 37%. Moreover, as corrosion proceeds, the corrosion product film was mainly composed of Cu2O, Cu-2(OH)(3)Cl. In addition, the Cu-10Ni alloy with Fe/Mn content of 1.69/0.69 has good corrosion resistance properties.
10.1002-maco.202213397	2	corrosion; surface; film; electrochemical; films; spectroscopy; layer; current; solution; potential; resistance; composition; x-ray; ions; showed	Copper tubes used in air-conditioners and refrigerators often fail due to ant nest corrosion (ANC) in formic acid environment. In this paper, corrosion behavior and corrosion mechanisms of copper tubes in formic acid (HCOOH) were analyzed by vapor corrosion tests, optical microscopy (OM), scanning electron microscope (SEM), energy-dispersive X-ray spectrometry (EDS). The effects of the surface condition on ANC of copper tube were also investigated. Results showed that ANC of copper tube was a spontaneous process. The surface integrity of copper tube surface oxide layer is not the decisive factor of ANC. ANC originated from the dissolution of the surface oxide layer in HCOOH, which exposed fresh copper matrix. ANC is a special electrochemical corrosion, where the copper matrix acts as an anode and the undissolved surface oxide layer acts as a cathode due to the potential difference. The accumulation of corrosion products consisting of Cu(HCOO)(2) and Cu2O can produce a wedge effect and generate many microcracks until to penetrate the copper tube wall. These findings would provide a deep understanding of the corrosion behavior of copper and copper alloys.
10.1002-maco.202213405	2	corrosion; surface; film; electrochemical; films; spectroscopy; layer; current; solution; potential; resistance; composition; x-ray; ions; showed	The passivity of pure copper over a wide pH range has been explored using potentiodynamic and potentiostatic polarization, Mott-Schottky analysis, and electrochemical impedance spectroscopy (EIS). The study shows that the passive film is a p-type semiconductor. The natural logarithm of the passive current density is found to linearly increase with the film formation potential. The passive state of copper is interpreted by optimizing the point defect model (PDM) on the EIS data. Kinetic stability diagrams are derived for pure copper in borate buffer based on the rate law for passive film growth in accordance with the PDM.
10.1002-maco.202314227	2	corrosion; surface; film; electrochemical; films; spectroscopy; layer; current; solution; potential; resistance; composition; x-ray; ions; showed	The corrosion behavior of two different Cu-Al-Mn-Ni alloys, pseudoelastic and pseudoplastic, was studied in a 0.6 M sodium chloride aqueous solution by monitoring the open circuit potential for 100 h and characterizing the resulting corrosion products. Electrochemical impedance spectroscopy analysis detected three processes related to the electrochemical double layer, a passive film and a diffusive contribution associated with the dissolution/precipitation of corrosion products. Potentiodynamic scans revealed a cathodically controlled corrosion mechanism and the presence of active-passive behavior at anodic potentials for both alloys studied. Polarization of the samples at selected potentials in the anodic branch allowed the investigation of the reactions involved, highlighting an improved corrosion resistance of the pseudoelastic alloy. The corrosion rates of the pseudoelastic and pseudoplastic alloys, after 100 h of immersion, were determined to be 0.007 and 0.011 mmpy, respectively. The post-experiment characterization was carried out by means of scanning electron microscopy, micro-Raman spectroscopy and X-ray diffraction, supporting the electrochemical results. Corrosion resistance was studied in two Cu-Al-Mn-Ni shape memory alloys, one pseudoplastic and one pseudoelastic, through electrochemical and post-experiment characterization. The corrosion products covered the samples over 60 h of immersion and the martensitic structure reduced the corrosion resistance in the pseudoplastic alloy. image
10.1002-maco.202414438	-1		The isothermal oxidation behavior of the Cu-11.35Al-3.2Ni-3.5Mn (wt%) shape-memory alloy (SMA) in the temperature range of 500-900 degrees C in oxygen was studied using the thermogravimetric (TG) method. TG curve showed that the alloy has parabolic isothermal oxidation characteristics. The effect of oxidation on the surface morphology and chemical composition of the Cu-Al-Ni-Mn alloy was determined by scanning electron microscopy, energy-dispersive spectroscopy, and X-ray photoelectron spectroscopy (XPS) analyses. The oxidation rate of SMA increases up to 700 degrees C, remains stable at 800 degrees C, and increases again up to 900 degrees C. The XPS analysis identified that the corrosion products mainly contained MnO2, MnO/Mn2O3, and Al2O3. The isothermal oxidation of a Cu-Al-Ni-Mn shape-memory alloy was studied in an oxygen atmosphere. The oxidation is parabolic, with an oxidation rate increase at 700 degrees C, remaining stable at 800 degrees C, and increasing again at 900 degrees C. The X-ray photoelectron spectroscopy analysis identified that the corrosion products mainly contained MnO2, MnO/Mn2O3, and Al2O3. image
10.1002-maco.202414461	2	corrosion; surface; film; electrochemical; films; spectroscopy; layer; current; solution; potential; resistance; composition; x-ray; ions; showed	This study developed a green and efficient surface protection method for Cu-Ni alloys. A zinc dibenzyl dithiocarbamate film was prepared on the surface of electrodeposited Cu-Ni alloys using the self-assembly method to improve the material's corrosion resistance in seawater. The influence of zinc dibenzyl dithiocarbamate concentration and self-assembly time on the corrosion resistance of the self-assembled films was investigated through electrochemical testing. The findings revealed that at a zinc dibenzyl dithiocarbamate concentration of 10 mmol/L and a self-assembly time of 20 min, the self-assembled film exhibited the most robust corrosion resistance, achieving a maximum corrosion inhibition efficiency of 97.70%. The self-assembly and adsorption mechanism of zinc dibenzyl dithiocarbamate were explored using molecular dynamics simulations and adsorption isotherms. The protective effect of self-assembled films was visually observed through salt spray testing. Zinc dibenzyl dithiocarbamate self-assembled film technology has high application prospects in the field of marine anti-corrosion. A self-assembled film of zinc dibenzyl dithiocarbamate was successfully formed on the Cu-Ni alloy coating, as depicted in the molecular dynamics simulation results. This self-assembled film effectively prevents Cl- corrosion, and the sample exhibits a matching circuit, as illustrated in the diagram. image
10.1002-maco.70053	-1		The effects of La microalloying on the microstructure and corrosion behavior of as-cast Cu-2.3Ni-0.6Si alloy in 3.5 wt% NaCl solution were investigated through OM, XRD, SEM, EDS, and an electrochemical workstation. Results indicate that as the La content increased from 0.05 to 0.20 wt%, the as-cast microstructure of the alloy initially coarsens and subsequently refines. La not only aggregates near the Ni2Si phase but also induces a preferred crystallographic orientation in in the Cu-2.3Ni-0.6Si alloy. Electrochemical corrosion results demonstrate that Cu-2.3Ni-0.6Si-0.05La exhibits optimal corrosion resistance in 3.5 wt% NaCl solution, achieving the highest charge transfer resistance (1974 Omegacm(2)), the maximum polarization resistance (292.31 k Omegacm(2)), and the lowest corrosion current density (1.49 mu Acm(-)(2)). The improved corrosion resistance is attributed to the combined effects of La's purification role and its promotion of preferential growth of low-index crystallographic planes with high planar density during solidification.
10.1002-mawe.201600780	-1		Bulk copper and Cu-7.0Ni-9.3Sn-6.3P (in wt%) filler alloys were brazed by microwave hybrid heating (MHH) and the results were compared with brazing using conventional furnace heating. Characterizations of the brazed joint were investigated through field emission scanning electron microscope, X-ray diffraction, shear strength test and Vicker's microhardness test. It was observed that microwave heating decreased to 94% of total processing time compared to conventional heating. Metallurgical study showed the formation of the alpha-copper, copper phosphide and nickel phosphide intermetallics at the joint interface for both heating methods. The reaction layer thickness of microwave brazed joint was three times thinner compared to the conventionally brazed joint. The optimum shear strength of the microwave brazed joints was found to be 108.8 MPa while it was 16% higher for the samples brazed using the conventional method. The failures of the microwave brazed joints showed a brittle cleavage structure while a mixed cleavage structure with tearing regions was observed for the conventionally brazed joints.
10.1002-mawe.201700125	-1		In this paper, copper-5wt%-tin (Cu-5wt%Sn) powder mixture was mechanically alloyed in order to study the solid solubility extension during the alloying process. Nanocrystalline supersaturated solid solution has been prepared in this system by high energy ball milling. Based on the thermodynamic model, the Gibbs free energy change in this alloy system during the formation of solid solution is calculated to be positive, which means that there is no driving force to form solid solution in copper-tin (Cu-Sn) immiscible system. It has been found that a large fraction of grain boundaries and a high density of dislocations play a significant role in the solid solubility extension of immiscible copper and tin.
10.1002-mawe.201700201	-1		The softening behavior of a 60% cold-drawn Cu-0.48Cr-0.16Sn alloy during annealing at temperatures between 450 degrees C and 750 degrees C was investigated. The mechanical properties and microstructures evolution of the alloy in both as-drawn and annealed conditions were analyzed using hardness measurement, transmission electron microscopy (TEM) and electron back-scatter diffraction (EBSD) technique. The results showed that the softening behavior of the alloy was strongly affected by precipitate coarsening, recovery and recrystallization, and was predominant by recrystallization when the temperature higher than 500 degrees C. The recrystallization kinetics was characterized by measurements of hardness. The obtained experimental data were evaluated in terms of the Johnson-Mehl-Avrami-Kolmogorov model. The values of the Avrami exponent were ranged from 0.87 to 1.36, and the activation energy of recrystallization was about 117.9kJmol(-1) for 60% cold-drawn Cu-0.48Cr-0.16Sn alloy, which suggested that recrystallization process of the Cu-Cr-Sn alloy was mainly controlled by grain boundary migration. The softening resistance of the Cu-Cr-Sn alloy is stronger than that of the pure copper due to the addition of Chromium (Cr) and Tin (Sn). In addition, the reduction in strain had a positive effect on the improvement of softening resistance.
10.1002-mawe.201900149	16	wear; composite; composites; powders; milling; particles; powder; wt; sliding; friction; hardness; matrix; mechanical; surface; properties	In this study, copper matrix composite materials with different ratios of carbon nanotubes were produced. The biggest problem faced in the production of carbon nanotube-reinforced composites is that carbon nanotubes do not distribute homogeneously in the matrix. A novel mixing technique was applied to overcome this problem. Hot pressing was used in sample production. A second high-pressure densification process was applied following the hot pressing process for enhancing the properties. The properties of both the hot-pressed specimens and the specimens to which a second high-pressure densification process was applied were characterized with the density measurements, microstructure examinations, and mechanical tests. The microstructure examinations showed that carbon nanotubes could be distributed homogeneously in the copper matrix with the mixing process applied. It was found out that the high-pressure densification process applied following the hot-pressing process increased the relative density and thus, all mechanical properties.
10.1002-mawe.202000141	-1		Mechanical alloying, cold pressing, and sintering were used for synthesizing bulk copper, copper-iron, and copper-iron-silicon carbide nanomaterials. The precipitation of iron during sintering of the supersaturated mechanically alloyed powder significantly enhanced the thermal stability of the nanocomposite against grain growth . Moreover, the hardness of sintered composites was found to increase with increasing milling time, which was attributed to the work-hardening, crystallite refinement, and increasing the relative density (decrease in porosity). Although the addition of silicon carbide did not affect the mean crystallite size of the bulk samples, it effectively increased the hardness of the nanocomposite based on its composite strengthening effect.
10.1002-mawe.202100076	-1		In this paper, copper-15 wt%-lead-1 wt%-tin (Cu-15wt%Pb-1wt%Sn), copper-15 wt%-lead-2 wt%-tin (Cu-15wt%Pb-2wt%Sn) and copper-15 wt%-lead-3 wt%-tin (Cu-15wt%Pb-3wt%Sn) powder mixtures were mechanically alloyed in order to study the solid solubility extension during the alloying process. Nanocrystalline supersaturated solid solutions have been prepared in copper-lead-tin (Cu-Pb-Sn) ternary immiscible system by mechanical alloying (MA). Based on the thermodynamic model, the Gibbs free energy changes in these alloys during the formation of solid solutions are calculated to be positive, which means that there are no driving force to form solid solutions in copper-lead-tin ternary immiscible system. It was found that a large fraction of grain boundaries and a high density of dislocations play a significant role in the solid solubility extension in copper-lead-tin ternary immiscible system.
10.1002-mawe.202200258	-1		In this study, Cu-Cr-Zr alloy specimens were first subjected to aging heat treatment at 500 degrees C for two different durations (2 hours and 4 hours). Three different coating processes (silver, silver/copper duplex, and copper/silver duplex) were applied to the aged specimens using the physical vapor deposition method. Tensile test, microhardness measurement, wear test, electrical conductivity measurement and structural analysis (x-ray diffraction and scanning electron microscope) were applied to the specimens. After the aging processes, the highest hardness and strength values of the Cu-Cr-Zr alloy were obtained in the specimens that were aged at 500 degrees C for 4 hours. When the wear resistance and electrical conductivity of the coated specimens were examined, it was determined that the specimens with duplex surface treatment performed better.
10.1002-mawe.202300413	14	strength; properties; conductivity; electrical; mechanical; cu-; grain; mpa; electrical conductivity; aging; precipitation; phase; mechanical properties; tensile; phases	The microstructure and properties of the Cu-12Sn-4Ni alloy were analyzed by incorporating varying amounts of the rare earth element cerium. The study compared the alloy's microstructure, hardness, strength, friction, and wear. The results showed that adding 0.04 % of rare earth cerium refined the grain size of the Cu-12Sn-4Ni alloy from 75 mu m to 200 mu m to 75 mu m to125 mu m. The hardness of the alloy increased by 22.78 % to 135.897 HV 0.1 after adding cerium, and the tensile strength of the alloy reached its highest peak at 452.08 MPa, with an elongation of up to 64.735 % after fracture. Additionally, the wear rate of the material decreased by about 38.6 % to 1.61x10-5 mm3/mm. In conclusion, the addition of the rare-earth element cerium successfully improved the structure and properties of the Cu-12Sn-4Ni alloy, leading to enhanced hardness, strength, and wear resistance.
10.1002-mawe.202400116	2	corrosion; surface; film; electrochemical; films; spectroscopy; layer; current; solution; potential; resistance; composition; x-ray; ions; showed	The galvanic corrosion of AISI 304 stainless steel/B30 copper-nickel alloy (304SS/B30 Cu-Ni) was investigated in neutral and acidic solutions with and without fluoride ion (F-) by wire beam electrode techniques, macro-electrochemical methods and scanning electron microscope. The results show that the passivation film was eroded by the synergistic effect of the proton (H+) and fluoride ion on the coupled sample surfaces, leading to changes significantly in the surface electrochemical activity and corrosion rate. The surface morphology after being immersed for 48 h in different solutions was observed by scanning electron microscope. However, 304 stainless steel is used as an anode relative to B30 copper-nickel alloy, with a typical polarity reversal, when fluoride ion is added to an acidic solution with pH=2.0.
10.1002-mawe.202400353	-1		The as-cast copper-chromium (Cu-Cr) alloy has been manufactured through casting and compared with the cold forged and the heat treated ones. The heat treated forged Cu-Cr sample properties were 105 HV 1 and 257 MPa compared to those obtained in the case of as-cast pure copper whose properties are 92 HV 1 and 182.88 MPa. Accordingly, the average impact energy value obtained in the case heat treated forged Cu-Cr sample was higher than those obtained in other samples. Die gussfertige Kupfer-Chrom-Legierung (Cu-Cr) wurde durch Gie ss en hergestellt und mit den kalt geschmiedeten und w & auml;rmebehandelten Proben verglichen. Die Eigenschaften der w & auml;rmebehandelten, geschmiedeten Kupfer-Chrom-Probe betrugen 105 HV 1 und 257 MPa im Vergleich zu denen der gussfertigen reinen Kupferprobe, deren Eigenschaften 92 HV 1 und 182,88 MPa betragen. Dementsprechend war der Durchschnittswert der Kerbschlagarbeit bei der w & auml;rmebehandelten geschmiedeten Cu-Cr-Probe h & ouml;her als bei den anderen Proben.
10.1002-pc.26706	16	wear; composite; composites; powders; milling; particles; powder; wt; sliding; friction; hardness; matrix; mechanical; surface; properties	Brass as a functional filler in the formulation of brake friction composites helps to improve the thermal conductivity, tribo-load bearing ability, fade, recovery and wear resistance of the brake pads. The commercial brass alloy has 70 wt% copper and 30 wt% zinc. In this work, the tribological performance of the brass powders with 60 wt% Cu +40 wt% Zn and 80 wt% Cu +20 wt% Zn having similar morphology with the commercial brass was evaluated. The commercial and the two modified versions of brass filler were introduced in the formulation. Totally nine phenolic brake composite were formulated and fabricated by varying the brass filler types and their composition (6, 8 and 10 wt%) in the brake formulations. The tribological performance of the developed brake pads was studied using a chase-type friction tester following IS 2742 test standard. The worn surface of the tested samples was studied using scanning electron microscopy and energy-dispersive X-ray spectroscopy. The tribological performance of the developed samples shows a nonlinear behavior concerning the variation in the composition. Therefore, statistical evaluation techniques such as hybrid analytical hierarchy process coupled with extension evaluation method (AHP-EEM) and analytical hierarchy process coupled with Preference Selection Index (AHP-PSI) were used to rank the developed samples based on the multiple tribological performance parameters. Based on the evaluation process the brake composite's composition with 8 wt% brass containing 70 wt% Cu and 30 wt% Zn has given the best overall performance.
10.1002-pssa.200306634	-1		The precipitation behavior of nano-scale Co particles formed in a Cu-Co alloy was studied by means of transmission electron microscopy and a Monte-Carlo simulation. Small coherent Co particles were randomly formed at the early stage of the precipitation process. Two or more Co precipitates linked together were linearly arranged to the <100> orientation of the copper matrix, at the later stage of the coherent precipitation. Finally, the particles lost their coherency to the Cu matrix, and incoherent Co precipitates appeared. The Monte-Carlo simulation, which took both chemical and magnetic interactions into account, strongly suggested that the coupling of coherent Co particles was realized as a result of the chemical and magnetic interactions between the Co particles, which are adjacent to each other.
10.1002-pssa.200406855	4	transformation; martensite; martensitic; phase; shape; beta; memory; shape memory; temperature; temperatures; martensitic transformation; gamma; transformation temperatures; effect; thermal	In the present study, the damping behavior of bulk Cu-11.9Al-2.5Mn (wt%) was investigated using a multifunction internal friction apparatus through the method of forced vibration over the temperature range from room temperature to 400degreesC. Two internal friction peaks are found at around 150degreesC and 325degreesC during heating. It is suggested that the high-temperature peak originates from the phase transition from martensite to austenite while the low-temperature peak from the pseudo-first-order phase transition associated with the thinning process of the twins. The related mechanisms are also discussed in terms of the interaction between the microstructure defects. (C) 2004 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.
10.1002-pssa.200406908	4	transformation; martensite; martensitic; phase; shape; beta; memory; shape memory; temperature; temperatures; martensitic transformation; gamma; transformation temperatures; effect; thermal	By internal friction technique, the behaviour of quenched-in vacancies and their influence on the martensitic transformation of the Cu-11.9Al-2.5Mn alloy has been studied. It is found that the reverse martensitic transformation temperature T-p follows a non-monotonous dependence on quenching temperature T-q of which the presence of a maximum T-p value is attributed to the different vacancy formation energies in the ordered and disordered phases. The background internal friction decreases with increasing ageing time due to migration of vacancies and resultant pinning effect on the phase interfaces and dislocations. (C) 2005 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.
10.1002-pssa.200521162	4	transformation; martensite; martensitic; phase; shape; beta; memory; shape memory; temperature; temperatures; martensitic transformation; gamma; transformation temperatures; effect; thermal	The effect of heat treatment on the damping behaviour of a Cu-11.9Al-2.5Mn(wt%) alloy was investigated and correlated with the martensite microstructures. It is found that elevated quenching temperature and rapid cooling can give rise to increased damping capacity due to the formation of favourable martensite microstructures characterized by coarse twin boundaries and a high twin content. (c) 2006 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.
10.1002-pssa.200778897	2	corrosion; surface; film; electrochemical; films; spectroscopy; layer; current; solution; potential; resistance; composition; x-ray; ions; showed	We report in this paper the preparation and characterization of Cu-In-O films. The samples were prepared by an annealing at 200 degrees C for 2 h in vacuum followed by an annealing at 400 degrees C for 3 h in air atmosphere (sample A) and directly by an annealing at 400 degrees C for 3 h in air atmosphere (sample B). The films were characterized for their structural, surface morphological, compositional, electrical and optical properties by using X-ray diffraction (XRD), scanning electron microscopy, electrical conductivity and optical measurement techniques (transmittance and reflectance). The XRD patterns revealed the presence of CuO and In2O3 phases. The absorption coefficients of Cu-In-O thin films in both cases are in the range (10(4)-10(5))cm(-1) and the direct optical band gaps are 3 eV and 3.55 eV for the samples B and A respectively. The electrical measurements show a conversion from a metallic phase to a semiconductor phase. n-type conductivity was found for the sample B, whereas the sample-A was highly resistive. (c) 2008 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.
10.1002-pssa.201100787	-1		Two copper based biaxially textured alloys containing 0.37 and 0.91 wt%-Fe have been investigated for the use as substrate material for coated conductors. Average full width at half maximum (FWHM) values of 7.3 degrees (CuFe0.37) and 6.8 degrees (CuFe0.91) for in-plane alignment and 7.2 degrees (CuFe0.37. CuFe0.91) for out-of-plane are achieved. Ultimate tensile strength for the two alloys is found to be much higher compared to the values for Cu and CuFe2.35. Hysteresis losses are dramatically reduced compared to other available substrate materials. Magnetisation data for both alloys obtained at 5 K show an anticipated saturation magnetisation (M-s) <0.35 mu Wb m kg(-1), which is less than 1% of pure Ni. [GRAPHICS] (c) 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim
10.1002-pssa.201228766	-1		The grain-boundary relaxation as well as corresponding internal friction (IF) mechanism in Cu-based shape-memory alloy was investigated taking Cu20.4Al8.7Mn (at%) as an example. A relaxational IF peak was found at around 214 degrees C during the heating process, whereas the peak completely disappears during the subsequence cooling process. The IF peak with the activation energy and pre-exponential factor of 1.60eV and 3.8x1018, respectively, shifting towards higher temperature as the measuring frequency increased indicates that the peak correlates to a thermal-activation process. The results obtained revealed that the viscous sliding of the grain boundaries should be the operative mechanism for the appearance of the peak. However, the appearance of the 2 precipitate particles formed during the heating process provides a reverse contribution to the peak, leading to the disappearance of the peak due to their pinning effect on the grain boundaries.
10.1002-pssa.201431598	2	corrosion; surface; film; electrochemical; films; spectroscopy; layer; current; solution; potential; resistance; composition; x-ray; ions; showed	A CuZn thin film combinatorial library was fabricated using a thermal co-evaporator. Using scanning electron microscopy (SEM), X-ray fluorescence spectroscopy (XRF) and X-ray diffraction (XRD) microcstructure, composition and crystallographic properties were investigated. Pure brass alloys were evidenced due to solid solution mixing of Cu and Zn. The crystallite size and lattice parameters were calculated and compared with values of pure Cu and -brass. With the aid of scanning in a wide compositional spread (3.4 at% Zn to 27 at% Zn). droplet cell microscopy (SDCM) the thermally evaporated CuZn thin film combinatorial library was screened for electrocatalytic effects on the formaldehyde oxidation. The obtained cyclic voltammograms show the occurrence of the formaldehyde oxidation leading to formic acid. CuZn thin film alloys were examined for their electrocatalytic oxidation of formaldehyde in an aqueous 0.1M Na2SO4 solution at different pH values using cyclic voltammetry. The highest catalytic effect was obtained at a pH value of 13.0 for a composition of Cu-8.0 at% Zn.
10.1002-pssa.201800340	4	transformation; martensite; martensitic; phase; shape; beta; memory; shape memory; temperature; temperatures; martensitic transformation; gamma; transformation temperatures; effect; thermal	Shape memory alloys are one of the most important families of functional materials due to superelasticity and shape memory properties. In particular Cu-Al-Ni alloys exhibit these properties at nanoscale, becoming potentially useful to design new smart MEMS. In this work, an anomalous behavior observed during nano-compression superelastic tests on Cu-Al-Ni shape memory alloy micro pillars is reported. The study is approached by nano-compression tests on micro and nano pillars milled by focused ion beam. The anomalous behavior on the superelastic effect is manifested by a sudden stabilization of the stress-induced martensite, which does not undergo the reverse transformation. A transition, from superelastic to pseudoelastic-twinning behavior, takes place during the nano-compression tests, and is evaluated through the load-depth curves and quantified by the mechanical damping coefficient , which undergoes a sharp change from ultra-high damping, >0.1, down to approximate to 0.01. The stabilization of the martensite occurs under two different experimental conditions, along cycling and by applying a very high stress during superelastic tests. In both cases, a further recovery of the initial superelastic behavior is registered. The mechanisms responsible for the observed stabilization and recovery are discussed, together with the implications and further requirements for technological applications in MEMS.
10.1002-pssa.201900923	-1		It is recognized that both parent phase aging and element addition can dramatically enhance the comprehensive properties of Cu-based shape memory alloys (SMAs). However, further in-depth studies are still needed to clarify the detailed laws and mechanisms. Herein, the effects of parent phase aging and Nb element on the microstructure, martensitic transformation (MT), and damping behaviors of a Cu-Al-Mn SMA are systematically studied. It is found that both the damping at low temperatures and the height of internal friction peak arising from the reverse MT of the Cu-Al-Mn SMA can be improved by the parent phase aging due to the increase in interfacial mobility. When the aging temperature reaches 600 degrees C, the best damping can be obtained. Nb forms AlNb3 phase in the Cu-Al-Mn matrix. Due to the pinning effect of the AlNb3 phase on grain boundaries, the grains of the Cu-Al-Mn SMA can be remarkably refined. With the increase in Nb content, the damping of the 600 degrees C aged Cu-Al-Mn SMA increases first and then decreases. The associated mechanisms are discussed. This work aims to provide theoretical basis and technical support for the improvement of damping property of Cu-based SMAs.
10.1002-pssa.202100203	-1		To solve a series of problems of Cu-Sn-Ti fillers, Ga is added to the fillers to promote its mechanical properties and microstructure. The metallographic structure of Cu-Sn-Ti-xGa filler metals is detected by optical microscope. Energy dispersive spectroscopy (EDS) areal, X-ray diffraction (XRD), and differential thermal analysis (DSC) are used to analyze the morphology and microstructure of the fillers. The results show that doped Ga can significantly decrease the melting point and increase mechanical properties of the fillers. The shear strength of the filler metals with 1% Ga content is 160% higher than without Ga. In addition, it is also observed that a small amount of Ga refine the CuSnTi filler metals matrix structure. The diffusion of elements in the filler metals is detected. Compared with Sn solid solution, Ga tends to form a solid solution with Cu. When the Ga content is 2 wt%, the shear strength of the filler metal decreases due to the appearance of coarse crystals at the bottom of the dimple. Through the study of the reaction layer between diamond and filler metal, it is found that Ga can increase the thickness of the interface reaction layer.
10.1002-pssa.202100750	1	shape; memory; shape memory; damping; martensite; martensitic; damping capacity; transformation; capacity; strain; superelasticity; temperature; cu-al-mn; shape memory effect; effect	Strain amplitude (SA) dependence of internal friction (IF) in a Cu-Al-Mn shape memory alloy (SMA) is investigated. Microstructure observation is conducted with the aim to clarify related mechanisms. It is found that the IF measured during the continuous heating process shows a nonmonotonous dependence on SA, that is, the IF increases first and then decreases. The increase of IF can be attributed to the mergence of martensite laths promoted by the reorientation of martensite variants, whereas the decrease of IF is related to the decrease in the density of moveable interfaces. The isothermal IF measured at low temperatures increases monotonously with the increase in SA, because the density of movable interfaces and the sliding distance of these interfaces in the tangential direction increase. Thermal cycles can significantly improve the isothermal IF because of the annihilation of quenched-in vacancies and the reorientation of martensite variants. At around 240 degrees C, the isothermal IF in all specimens shows a nonmonotonous dependence on SA, which can be ascribed to the dragging effect of quenched-in vacancies on dislocations and the breakaway of dislocations from these vacancies when the SA is high enough .
10.1002-pssa.202200237	6	grain; deformation; strain; strength; dislocation; cu-; tensile; size; ecap; grain size; sfe; ductility; hardening; high; stress	Cu/Ti laminated sheets with heterogeneous Ti layers are successfully fabricated by accumulative roll bonding (ARB). The microstructure during processing is characterized by scanning electron microscopy (SEM) and electron backscattered diffraction (EBSD). During the deformation of the constituent metals, the hard Ti layers neck preferentially but with a continuous layered structure. Upon four ARB cycles, there are five Ti layers with different microstructure states and grain sizes (from 1.3 to 0.5 mu m) in the ARB4 sample. Tensile test of ARB4 sample indicates excellent comprehensive mechanical properties, compared with pure Cu and pure Ti, it has higher ultimate tensile strength (508 MPa), and the elongation (9.2%). In the result of loading-unloading-reloading test, there is a strain gradient during the tensile process due to heterogeneous existence of Ti layers, which produces a multilevel hetero-deformation-induced (HDI) stress strengthening and improves the coordinated deformation ability of the sample. Second, layered structure and interface with alternate strong and weak bonding can effectively hinder the propagation of cracks to outline higher strength with improved ductility. This structural design helps to prepare laminated materials sheet with excellent comprehensive mechanical properties through the ARB process.
10.1002-pssa.202300229	-1		Porous Cu-Al-Ni shape memory alloys (SMAs) are fabricated via powder metallurgy method using Cu, Al, Ni powders and Cu-Al-Ni alloy powder as raw materials, respectively. It is found that the two kinds of specimens have similar macroscopic morphologies: connected pores are uniformly distributed in the Cu-Al-Ni matrix, forming a 3D network structure. By comparison, the specimen fabricated using alloy powder has much finer microstructures than the specimens fabricated using Cu, Al, Ni powders. After adding Ce element to the latter, the microstructure of the Cu-Al-Ni matrix is significantly refined because of the formation of Ce-rich particles. Damping tests show that the latter has superior damping capacity than the former. With the increase of Ce content, the damping of the latter increases first and then decreases. When the Ce content reaches 0.05 wt%, the highest damping can be achieved. Correlated mechanisms are discussed based on the microstructural observations.
10.1002-pssa.202300672	-1		Herein, the magnetic properties and elastocaloric effects of Cu70Al19 + 0.5xMn11-0.5x (x = 0, 1, 2, 3) alloys are investigated. The resistance versus temperature curves indicate that the phase transition temperature increases as the Mn content decreases. In particular, the Cu70Al20.5Mn9.5 alloy exhibits a phase transition temperature close to room temperature. Therefore, the elastocaloric effects of this alloy are examined under stresses ranging from 200 to 500 MPa. The results show that the adiabatic temperature change of the alloy under a stress of 500 MPa reaches 9.8 K. Furthermore, the magnetization curves at 300 K reveal that the magnetic properties of the alloy significantly improve after undergoing low-temperature aging treatment. The X-ray diffraction patterns show that this improvement can be attributed to the transformation of the beta 1 phase to the ferromagnetic phase beta 3. Overall, the Cu70Al20.5Mn9.5 alloy demonstrates elastocaloric and magnetic properties comparable to those observed in certain Ni-Mn-based alloys. Herein, the magnetic properties and elastocaloric effects of Cu70Al19 + 0.5xMn11-0.5x (x = 0, 1, 2, 3) alloys are investigated. The results show that the adiabatic temperature change of the alloy under a stress of 500 MPa reaches 9.8 K. After low-temperature aging treatment, the alloy's magnetic properties undergo a paramagnetic-to-ferromagnetic transition.image (c) 2023 WILEY-VCH GmbH
10.1002-pssa.202400740	-1		In this research, the magnetoelectric and mechanical properties of Cu77-xNi15Sn8Mnx (x = 0, 5, 10, 15, 20 at%) alloy are systematically studied. In the results, it is demonstrated that the magnetic properties of the alloy increase with an increase in the Mn content, as evidenced by the thermomagnetic curve and isothermal magnetization curve. The magnetic properties of the annealed Cu57Ni15Sn8Mn20 alloy reach about 15 emu g-1 at room temperature, and the Curie temperature (Tc) reaches about 360 K in a 1 k Oe magnetic field. The characteristic peak of the magnetic transition in the AC magnetic susceptibility test also corresponds to the Curie temperature. An electrical performance test calculated the resistivity of the alloy, the resistivity of Cu57Ni15Sn8Mn20 in its annealed state is about 26% lower than that of Cu77Ni15Sn8. Furthermore, the hardness test reveals that the Vickers hardness of the Cu57Ni15Sn8Mn20 alloy is about 246.2 HV, demonstrating its excellent mechanical properties. In the research, it is shown that the doping of Mn elements plays a crucial role in the magnetic properties of Cu-Ni-Sn alloys. By adjusting the content of the Mn element, the magnetic performance can be controlled. A valuable approach is provided for enhancing the performance of magnetic Cu alloys.
10.1002-pssb.200402039	-1		The screening dependence of superconducting state parameters (lambda, mu*, T-c, alpha and N0V) of nine metallic glasses of the Cu-Zr system has been studied in the BCS-Eliashberg-McMillan framework by employing five forms of dielectric screening function in conjunction with Ashcroft's potential. It is observed that the electron-phonon coupling strength (lambda) and transition temperature (T-c) are quite sensitive to the form of the dielectric screening, whereas the Coulomb pseudopotential (mu*), isotope effect exponent (alpha) and effective interaction strength (N0V) show weak dependences on screening function. The RPA form of dielectric screening is observed to yield the best results for all the glasses of the Cu-Zr system studied in the present work. Present computations yield almost linear variation of T-c with concentration x of Cu in the Cu-Zr system, which is in agreement with the experimental data. A linear T-c equation is proposed by fitting the present results for RPA screening, which is in conformity with other results for the experimental data. (C) 2004 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.
10.1002-pssb.200844488	9	magnetic; magnetization; magnetoresistance; temperature; superparamagnetic; annealing; gmr; field; magnetic properties; ferromagnetic; granular; samples; magnetic field; melt-spun; particles	Magnetization X-ray absorption fine structure, and resistivity measurements on two samples of Cu + 2.0 at% Fe are reported here. The first sample, prepared by annealing at 950 degrees C for 2 days followed by rapid quenching, consists of a random solid solution of Fe in Cu. The paramagnetic susceptibility follows the Curie-Weiss law 10 K <= T <= 300 K yielding an effective Fe moment of 1.9 +/- 0.1 mu(B) and a Curie temperature -2.0 +/- 2.0 K. The second sample, prepared using the heat treatment above followed by a second annealing at 620 degrees C for 2h, consists of face-centered-cubic (FCC) gamma Fe precipitates in the Cu matrix. The formation of the Fe precipitates reduces the electronic scattering, which is reflected in the resistivity behavior. The FCC atomic short-range order for the Fe is demonstrated with X-ray absorption fine structure. The Paramagnetic susceptibility follows the Curie-Weiss law 100 K <= T <= 300 K yielding an effective Fe moment of 1.8 +/- 0.2 mu(B) and a Curie temperature -58 +/- 10 K, consistent with an antiferromagnetic (AFM) ordering. The results are discussed in the light of previous neutron investigation of the ordered magnetic structures. (C) 2009 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim
10.1002-pssb.201700422	-1		We study the giant elastocaloric effect in a Cu-Zn-Al shape-memory alloy by means of simultaneous calorimetry and dilatometry measurements under applied uniaxial compression which have been carried out with a bespoke experimental setup. The output data allow a unique quasidirect and indirect characterization of the thermal response that provides accurate S and T values. We report a large thermal response of |S|=22JKkg(-1), |T|=12.3K, and RC=325Kkg(-1) driven by moderate uniaxial compression changes of 32.2MPa, which is comparable with the performance of the best magnetocaloric materials. In view of the hysteresis effects, the thermal response is predicted to exhibit reversible values for |sigma|=32MPa.
10.1002-pssb.202000140	11	glass; bulk; metallic; bulk metallic; gfa; bmg; glassy; metallic glass; ability; bulk metallic glass; amorphous; addition; crystallization; mm; glass-forming	The effect of oxygen content on the glass-forming ability of binary Cu-Zr alloys is investigated by the in situ observation of the cooling process during the containerless solidification using an aerodynamic levitation technique. The oxygen content of approximate to 0.72 at% induces the crystallization of undercooled liquid Cu(47)Zr(53)alloy, whereas that of approximate to 0.33 at% enhances the glass-forming ability and leads to the formation of bulk metallic glass when compared with the alloy containing approximate to 0.20 at% of oxygen. The differential thermal analysis of the bulk metallic glass samples shows the extension of the undercooled liquid region with an increase in the oxygen content from 0.20 to 0.33 at% in the Cu(47)Zr(53)alloy. Time-resolved synchrotron X-ray diffraction experiments reveal structure evolution of the Cu(47)Zr(53)alloy from the undercooled liquid to glass or crystal. The effect of oxygen on the glass-forming ability is qualitatively described in terms of reducing the critical cooling rate of the alloy.
10.1002-pssb.202000262	13	clusters; atomic; glass; atoms; composition; dynamics; metallic; icosahedral; glasses; simulations; molecular; cu-zr; molecular dynamics; metallic glasses; structural	Using a molecular dynamics (MD) simulation and an embedded atom method (EAM), this article aims to study the structural properties of five Cu- and Ag-based metallic glasses (MGs) with different compositions (Cu75Ag25, Cu50Ag50, Ag75Cu25, Cu-monatomic, and Ag-monatomic MGs) to shed light on the effect of composition on MGs' properties. According to the radial distribution function (RDF) analysis, it is revealed that Ag atoms promote the glass forming ability (GFA) of the samples. Furthermore, increasing Ag content is found to favor the formation of face-centered cubic (fcc) clusters and reduce the atomic fraction of icosahedral clusters, and this seems normal, because the distorted icosahedra are just an intermediate state between the icosahedra structure and the fcc structure as mentioned in the literature. Moreover, it is shown that Ag atoms tend to be at the center space of clusters with higher coordination numbers. It is also found that the obtained microstructure of the MGs, especially the full icosahedra, influences their mechanical response toward uniaxial tensile loading, as it enhances their strength by resisting to shear strain and reducing their plasticity, which encourages the accumulation of shear strain in shear bands.
10.1002-pssb.202400100	13	clusters; atomic; glass; atoms; composition; dynamics; metallic; icosahedral; glasses; simulations; molecular; cu-zr; molecular dynamics; metallic glasses; structural	The Cu-Zr-based metallic glasses (MGs) have recently sparked great attention due to their outstanding properties and their improved glass-forming ability (GFA). Therefore, a molecular dynamics study is performed to investigate the effect of composition on the structural analysis methods including the radial distribution function, Voronoi analysis, and coordination number of three Cu-Zr-Al alloys to predict the system having the much higher GFA. The T-V curves during the cooling process involve transitioning the liquid state to the glassy state, demonstrating that Cu44Zr52Al8$\left(\text{Cu}\right)_{44} \left(\text{Zr}\right)_{52} \left(\text{Al}\right)_{8}$ and Cu40Zr47Al13$\left(\text{Cu}\right)_{40} \left(\text{Zr}\right)_{47} \left(\text{Al}\right)_{13}$ are good glass formers. The findings reveal that the splitting of the second peak in the radial distribution function at Cu44Zr52Al4$\left(\text{Cu}\right)_{44} \left(\text{Zr}\right)_{52} \left(\text{Al}\right)_{4}$ results in more pronounced one. It is also indicated that with increasing Al content, the system undergoes a decrease toward the CN. Additionally, higher Al content contributes to the higher content of the full icosahedra as well as the distorted icosahedra, consequently, higher GFA. These structures, demonstrate various modes of linkage including vertex sharing, edge sharing, face sharing, and interpenetrating sharing, resulting in more dense atomic packing. Finally, strong correlations between the atomic compositions with the structural properties are shown, which can help to predict the much higher GFA system. Molecular dynamics simulations are conducted to address a critical point of the structural explanation of glass-forming ability in the Cu-Zr-Al ternary system. The structural dependence of composition using a set of structural analysis in order to attemptingly predict good glass forming composition in Cu-Zr-Al system in the Al atomic percentages (6, 8, and 13 at%)$\left(\right. 6 , \textrm{ } 8 , \text{ and } 13 \text{ at%} \left.\right)$ is studied.image (c) 2024 WILEY-VCH GmbH
10.1002-sia.1610	-1		An alloy of Cu-9at%Al(111) has been oxidized in a low-energy electron diffraction (LEED)/AES and a scanning AES instrument at elevated temperatures. Dosing with 1300 L of oxygen at 995 K gives rise to well-ordered oxide layer formation on the Cu-9at%Al alloy. The structure of the ordered oxide confirmed by LEED is (7/root3 x 7/root3) R30degrees. The chemical state of the oxide was Al2O3. The morphology of the surface observed with SEM in the scanning AES instrument revealed flat oxide growth with triangular defects of the same orientation. The possible epitaxy between the alloy substrate and alumina layer has been discussed. Copyright (C) 2003 John Wiley Sons, Ltd.
10.1002-sia.1788	2	corrosion; surface; film; electrochemical; films; spectroscopy; layer; current; solution; potential; resistance; composition; x-ray; ions; showed	By means of the combined use of XPS and scanning electron microscopy + energy dispersive spectrometry (SEM + EDS), the microchemical structure of long-term corrosion products grown on Aes Rude, i.e. archaeological unworked lumps of Cu-based materials, has been carried out. In ancient Italy, these materials have been used as currency, as a medium of exchange and as a form of saving, from the sixth to the third centuries BC before the use of the struck metallic coins. The results of the microchemical investigation disclose their apparently unusable nature for any functional applications or possible use, being constituted of highly ferruginous leaded copper, and demonstrate that Aes Rude were a primitive form of currency as suggested by archaeologists. Furthermore, XPS and SEM + EDS results give evidence on the corroded external region of the presence of Cu (II) hydrates mixed with hydrated iron oxide and aluminium-silicon phases coming from the soil that have been incorporated into the patina. This information is useful to identify the material nature of these archaeological artefacts and to select tailored conservation strategies finalized to ensure long life to these relevant ancient materials. Copyright (C) 2004 John Wiley Sons, Ltd.
10.1002-sia.1790	2	corrosion; surface; film; electrochemical; films; spectroscopy; layer; current; solution; potential; resistance; composition; x-ray; ions; showed	XPS analysis of different forms of copper sulfate, including antlerite, brochantite, posnjakite, chalcanthite and anhydrous copper sulfate, as well as pure copper and its oxides cuprite and tenorite, was carried out. These products most often occur when dealing with atmospheric corrosion of copper and bronze in sulfur-bearing environments. These compounds were minerals, commercial products, or grown on pure copper by artificial weathering. Spectral features such as peak energy and line shape for Cu 2p, Cu LMM, O 1s and S 2p bands were examined. Comparison of the measurements obtained proves the efficiency of XPS in differentiating the various compounds. Copyright (C) 2004 John Wiley Sons, Ltd.
10.1002-sia.2081	-1		We report on a comparative measurement of intergranular bismuth coverage on a copper substrate using Auger electron spectroscopy (AES), x-ray photoelectron spectroscopy (XPS) and Rutherford backscattering spectroscopy (RBS). Bicrystalline copper samples were put in presence of bismuth vapour at 500 degrees C (consequently embrittled by the grain-boundary penetration of Bi atoms), water-quenched and subsequently fractured at room temperature. Each fracture surface was analysed by AES, XPS and RBS with the help of quantitative procedures developed for each of the three techniques. All possible sources of discrepancy were carefully examined. The combined quantitative approaches have led to excellent agreement. Such a good agreement constitutes a necessary condition to begin a critical discussion on the mechanisms potentially involved in the liquid metal embrittlement (LME) phenomenon. Copyright (c) 2005 John Wiley & Sons, Ltd.
10.1002-sia.2744	2	corrosion; surface; film; electrochemical; films; spectroscopy; layer; current; solution; potential; resistance; composition; x-ray; ions; showed	Corrosion of pure copper surfaces in chloride-containing solutions leads to the combined local and global attack of the surface. To be able to identify both reactions, it is important to know the nature of the corrosion products formed in both processes. This was done by investigation of the corroded surface using field emission AES (FE-AES). The spectra recorded from different locations on the surface were compared to reference spectra using target factor analysis (TFA). The study confirmed the porous nature of the general corrosion product layer. In this layer both Cu2O and CuO are present, the former in higher concentrations. In the local attack sites more CuO than Cu2O is detected and also more chlorides are present. Copyright (c) 2008 John Wiley & Sons, Ltd.
10.1002-sia.4803	2	corrosion; surface; film; electrochemical; films; spectroscopy; layer; current; solution; potential; resistance; composition; x-ray; ions; showed	Archaeological bronze artefacts are covered with corrosion products, that is, the patinas, whose nature depends on different degradation processes occurring during long-term burial. As a consequence of the corrosion phenomenon, surfaces of archaeological metal objects are composed of a complex structure. By means of the combined use of different analytical techniques such as XPS, scanning electron microscopy combined with energy dispersive X-ray spectroscopy, optical microscopy and X-ray diffraction, some typical patinas grown on Roman and Punic archaeological bronze artefacts have been studied in details by selecting a suitable methodological approach to acquire micro-chemical, morphological and structural information. The XPS measurements of Cu 2p, Cu LMM and valence band spectra of archaeological objects and reference samples such as CuCl2, CuCl, Cu2Cl(OH)3, Cu2O and CuO allowed us to identify the different copper oxidation states and crystallographic phases present in a patina. Moreover, the XPS elemental concentration depth profiles have yielded information about the stratified outermost layers and the occurrence of the migration phenomenon from bulk to surface due to selective corrosion processes. These pieces of information compared with those achieved via scanning electron microscopy combined with energy dispersive X-ray spectroscopy, optical microscopy and X-ray diffraction reveal the complex chemistry and morphology of the patina, highlighting also the correlation between patina and burial context. Copyright (c) 2012 John Wiley & Sons, Ltd.
10.1002-sia.4841	2	corrosion; surface; film; electrochemical; films; spectroscopy; layer; current; solution; potential; resistance; composition; x-ray; ions; showed	Benzotriazole (BTA) is an inhibitor molecule, commonly used to protect copper and copper-based archaeological artefacts from degradation processes such as the bronze disease. The aim of the present work was to study in details the inhibition mechanism of the BTA molecule on pure copper and coppertin alloy (called CNR 128) by the surface-sensitive techniques (field emission SEM with energy-dispersive X-ray spectrometer and XPS). To perform this investigation, the typical corrosion products of the patina, including cuprite (Cu2O) and atacamite (Cu2Cl(OH)3) compounds, were grown on pure copper and CNR 128 alloy. The BTA molecule was then applied on the surface of the prepared samples, following the method that is commonly used in the conservation of artefacts in cultural heritage. During the analyses of pure copper substrate, it was revealed by XPS that BTA molecule favours the formation of Cu(I) species, when it is adsorbed on an atacamite-enriched surface. On the contrary, when BTA molecule is adsorbed on a cuprite-enriched surface, it is promoted the formation of Cu(II) species. Instead, for degraded CNR 128 alloy where atacamite or cuprite were the main component of the patina, XPS results showed that the chemical nature of the bronze surface is present Cu(II) oxidation state. Copyright (c) 2012 John Wiley & Sons, Ltd.
10.1002-sia.5539	2	corrosion; surface; film; electrochemical; films; spectroscopy; layer; current; solution; potential; resistance; composition; x-ray; ions; showed	The synthesis of polyaniline coatings on the copper (Cu) surface has been investigated by using the galvanostatic method. The synthesized coatings were characterized by Fourier transform infrared spectroscopy, UV-visible absorption spectrometry and scanning electron microscopy. The anticorrosion performances of polyaniline coatings were investigated in 0.5M HCl medium by the potentiodynamic polarization technique and electrochemical impedance spectroscopy. The corrosion rate of polyaniline-coated Cu was found to be approximate to 27 times lower than bare Cu, and potential corrosion increased from -0.21V versus Ag/AgCl for uncoated Cu to -0.19V versus Ag/AgCl for polyaniline-coated Cu electrodes. Electrochemical measurements indicate that polyaniline coating has good inhibiting properties with a mean efficiency of similar to 96% at 10mAcm-2 current density applied on Cu corrosion in acid media. The results of this study clearly ascertain that the polyaniline has an outstanding potential to protect Cu against corrosion in an acidic environment. Copyright (c) 2014 John Wiley & Sons, Ltd.
10.1002-sia.5865	2	corrosion; surface; film; electrochemical; films; spectroscopy; layer; current; solution; potential; resistance; composition; x-ray; ions; showed	Corrosion layers in some copper and bronze archaeological objects from Haft Tappeh archaeological site, southwest Iran, were studied. For this purpose, optical microscopy, scanning electron microscopy with energy dispersive X-ray microanalysis, micro-Raman spectroscopy and X-ray diffraction methods were applied to observe corrosion stratigraphy and their characteristics as well as identification of chemical composition and phase determination of different corrosion layers. Based on optical and electron microscopy, three different corrosion strata were identified in cross section of different metallic objects including various red, green, white-grey powdery and dark internal compact layers. Scanning electron microscopy with energy dispersive X-ray microanalysis on different corrosion layers revealed that Cu, Sn and Cl are the main elements in the chemical composition of different layers. Tin-rich phases were detected in white-grey and dark layers that may be formed because of the internal oxidation of tin as well as the decuprification (selective dissolution of copper) phenomena occurring during long-term burial period in the soil. Also, the XRD and micro-Raman spectroscopy results proved that the main corrosion products are nantokite (CuCl), copper trihydroxychlorides and copper oxides. The combination of these analytical methods allows us to explore the surface and internal corrosion layers of the archaeological copper and bronze samples, and major interest is on studying their chemistry, microstructural properties and corrosion stratigraphy. Copyright (C) 2015 John Wiley & Sons, Ltd.
10.1002-smll.202501320	-1		Hydrogel infusion-based additive manufacturing (HIAM) is a chemically versatile solid-state processing pathway that allows 3D structuring of ceramics and alloys with micro-scale precision. Using thermal treatments of 3D-printed metal ion-infused gels, this process generates intricate microstructures throughout their complex phase evolution. Through investigation of the HIAM-produced CuxNi1-x alloy system, substantial grain growth after reduction is shown to drive the formation of numerous annealing twins and entrap unreduced oxide nano-inclusions, resulting in hierarchical composite microstructures. These features appear to elevate the average nanoindentation hardnesses by up to four times that of bulk annealed CuxNi1-x. Uniaxial compression of micropillars milled from individual grains reveals composition dependence on the scaling of the smaller is stronger size effect. This compositional dependence of deformation mechanisms arises from changes in reduction kinetics which influence the density of inclusions and voids developed by the HIAM process. This work highlights the rich microstructural landscape accessible to HIAM-produced alloys and provides a useful pathway for the characterization and tuning of superior mechanical performance in additively manufactured alloys.
10.1002-srin.201100319	8	hot; deformation; strain; strain rate; dynamic; hot deformation; recrystallization; dynamic recrystallization; flow; rate; flow stress; compression; constitutive; degrees; stress	The true stressstrain curve of CuFe16Mn0.6C twinning induced plasticity (TWIP) steel was studied with a compression test on Thermecmastor-Z thermal simulator at a temperature range of 8501150 degrees C and strain rate range of 0.0330?s-1. The influence of deformation temperature and strain rate on high-temperature flow stress and critical recrystallization behavior of the TWIP steel was investigated. It is concluded that the peak flow stress of CuFe16Mn0.6C under high-temperature deformation decreases as the temperature increases but increases with the strain rate. Meanwhile at strain rate of 0.03 and 30?s-1 obvious peak stresses are observed which demonstrates the dynamic recrystallization. The constitutive equation of CuFe16Mn0.6C under high temperature deformation is calculated by linear regression method. The activation energy is 505?kJ?mol-1. The relationship between critical strain of dynamic revrystallization and ZenerHollomon parameter is determined by the curve between strain-hardening rate and flow stress.
10.1002-srin.202100016	-1		A new low magnetic shielding (LMS) copper alloy (Cu-40Mn-2Al) connected with copper through tungsten inert gas (TIG) welding to form a new two-stage mold for soft-contact electromagnetic continuous casting is described. Experimental and numerical simulation methods are used to study the LMS effect, the cooling performance, and the strength of the two-stage mold. With the solid solution of a large proportion of the Mn and a little of Al elements in the copper, the electrical resistivity of the copper alloy increases significantly. Furthermore, the thickness of the skin layer is about 1.5 times larger than that of the base alloy (Cu-10Mn-5Si-3Al-1.2P-1Ti), which greatly reduces the LMS effect. Numerical simulation results agree well with the experimental results on the LMS effect of the copper alloy. The electromagnetic force reaches the maximum value at the meniscus and gradually attenuates from the surface to the center of the billet. Critically, the electromagnetic force exceeds the critical value required for pushing the molten steel away the wall of the mold. Thus, the developed copper alloy achieves the requirements for two-stage mold with the properties of the LMS effect, the well cooling effect, the high strength .
10.1002-srin.202400254	-1		Nonoriented electrical steel for new energy vehicles should have high strength and excellent magnetic properties simultaneously. However, it is challenging to optimize mechanical and magnetic properties simultaneously during nonoriented electrical steel processing. This article prepares nonoriented electrical steel with high strength and excellent magnetic properties by Cu-Ni alloying, and the evolution of properties of Cu-Ni-alloyed nonoriented electrical steel during aging and underlining mechanisms is studied. The optimal strength is achieved when aging for 10 min with a yield strength of 773 MPa, where the magnetic induction intensity (B50) is 1.66 T, and the iron loss (P1.0/400) is 18.07 W Kg-1. The optimal strength is attributed to the Cu-Ni recombination, which induces a rapid precipitation of numerous small-sized Cu-rich phases within a short period. Besides, the main strengthening mechanisms of the small-size Cu-rich phases are modulus strengthening and ordered strengthening. Furthermore, the small-size Cu-rich phases with B2 and body-centered cubic structure in the earlier aging period do not deteriorate the magnetic properties of the steel. Nevertheless, in the late aging period, due to the coarsening of the precipitated Cu-rich phase with face-centered cubic structure and the abnormal growth of some grains, the eddy current loss increases, leading to worsen magnetic properties. This study successfully produces a nonoriented electrical steel with a yield strength of 773 MPa, where B50 is 1.66 T, and P1.0/400 is 18.07 W kg-1. This optimal strength is attributed to the Cu-Ni recombination, which induces a rapid precipitation of numerous fine coherent Cu-rich phases within a short period. Importantly, these precipitates do not deteriorate the steel's magnetic properties.image (c) 2024 WILEY-VCH GmbH
10.1002-srin.202400352	8	hot; deformation; strain; strain rate; dynamic; hot deformation; recrystallization; dynamic recrystallization; flow; rate; flow stress; compression; constitutive; degrees; stress	The hot compression tests (T = 850-1100 degrees C, epsilon(center dot) = 0.1-10 s-1) of Cu-Cr-Ni bridge weathering steel with different Cr content (0.46% (#1), 0.64% (#2)) were performed on Gleeble-3800-D thermomechanical simulator. The effects of Cr content on hot deformation and microstructure evolution are systematically investigated by the Arrhenius constitutive equation, processing map, electron backscatter diffraction technology, and transmission electron microscope. In the results, it is demonstrated that the increase of Cr content from 0.46% to 0.64% enhances the solution strengthening and inhibits the dynamic recrystallization of the experimental steels during hot compression, resulting in the increase of flow stress. The Arrhenius constitutive equation with strain compensation is constructed. The increase of Cr content results in an augmentation of hot deformation activation energy, rising from Q#1 = 358.47 kJ mol-1 to Q#2 = 396.79 kJ mol-1, causing the increase of deformation resistance of Cu-Cr-Ni bridge weathering steel in hot compression. The optimal hot processing window of #1 and #2 experimental steels is as follows: epsilon(center dot) = 0.1-0.2 s-1, T = 1050-1100 degrees C, epsilon(center dot) = 0.1-0.15 s-1, and T = 1050-1100 degrees C, the increase of Cr content leads to the narrowing of the hot processing window of the experimental steels. The hot deformation behavior and microstructure evolution of Cu-Cr-Ni bridge weathering steel with different Cr contents (0.46%/0.64%) are investigated by hot compression tests. The increase of Cr content enhances the solution strengthening and inhibits the dynamic recrystallization during hot compression, resulting in the increasing of flow stress and the narrowing of the hot processing window of the experiment steel.image (c) 2024 WILEY-VCH GmbH
10.1002-srin.202500286	-1		Electric pulse, as a new environmentally friendly technology, can effectively improves the traditional solid solution aging heat treatment process, accelerate atomic diffusion, promotes the nucleation of second-phase precipitation, and shorten the precipitation time. Therefore, this study utilizes the electric pulse technique to prepare a Cu-rich phase. The mechanical properties are studied and found to peak at a relatively short pulse aging time. The Vickers hardness value stabilized around 125 HV, and the tensile strength reaches 561.5 MPa. The grains in the necking region are elongated during uniaxial tension, and the twin structures were severely disrupted. In addition, the degree of damage to the tensile samples is evaluated using digital image correlation technology. The hard-oriented copper texture {112}<111> and the S-type texture {123}<634> played a crucial role in stabilizing the plastic deformation of the structure. Cu-rich phases preferentially nucleated at planar defects such as dislocations and grain boundaries. With the extension of the pulse aging time, the average size of the Cu-rich phase gradually increases from 12.5 to 17.1 nm, but the density of the Cu-rich phase gradually decreases.
10.1002-stc.327	3	sma; shape; shape memory; memory; smas; superelastic; bars; damping; cu-al-mn; mechanical; bending; applications; numerical; sma bars; material	This paper presents a simulation-based benchmark control study in which shape memory alloy (SMA)-based displacement restraining damping devices are proposed to control the seismic response of a full-scale three-dimensional seismically excited highway bridge. In this Phase II benchmark problem, the bridge is fully isolated at both the abutments and the central pier location using nonlinear hysteretic bearings with a lead core on the inside and an elastomer surrounding the lead core. The SMA restraining damping device is a passive control device employing superelastic Cu-Al-Be alloy wires as its core re-centering component, which restrains the base-isolated bridge from excessive displacement responses, especially under extreme earthquake events. In this benchmark study, a total of 20 such passive control devices are supposed to be installed at the isolation level between the deck and the isolators on bridge piers and center column at 10 locations, each location consisting of a single orthogonal pair to control the responses in both directions. The performance of the passive control devices is analyzed in terms of the performance indices in the benchmark problem definition at a variety of ambient environment temperatures at 23, 0. -25 and -50 degrees C, respectively. The results of this simulation-based benchmark control study show that the proposed passive control device can effectively reduce the excessive displacement responses and permanent bearing deformations of the benchmark base-isolated bridge subjected to strong ground motions, and temperature seems to have little effect on the performance of the superelastic Cu-Al-Be restraining damping device in bridge response control. Copyright (C) 2009 John Wiley & Sons, Ltd.
10.1002-xrs.2972	2	corrosion; surface; film; electrochemical; films; spectroscopy; layer; current; solution; potential; resistance; composition; x-ray; ions; showed	Studies of Iberian votive figurines have extended our knowledge of Iberian culture and have provided valuable information both on technological aspects of the metal processing and on social and religious patterns inside these communities. In this study, we present an energy dispersive X-ray fluorescence analysis of the copper alloys of a selection of 32 Iberian votive figurines and two fibulae (fourth-third centuries BC) in the collection of the Museum of Prehistory in Valencia. The collection comprises 98 bronze objects from the Iberian sanctuaries of Collado de los Jardines (Santa Elena) and Altos del Sotillo (Castellar), in Jaen, Spain. The results reveal a diversity of Cu-Sn-Pb alloys among the votive figurines, including copper, leaded copper (Pb>2wt%, Sn<2wt%), binary bronzes (Sn>2wt%, Pb<2wt%), and ternary bronzes (Sn>2wt%, Pb>2wt%). The analyses of the bronze alloys are compared with those of other regional votive collections dating from the same period.
10.1002-xrs.3199	-1		In this study, the mass attenuation coefficients of copper-silver thin-film alloys, produced by the thermal evaporation method at various concentrations, were measured at six different energies in the range of 14.93-48.82 keV (keV) by X-ray Fluorescence technique (XRF). A(241)Americium radioisotope source, having 50 mCi intensity and 59.54 keV energy photons, was used to stimulate the samples, and an Ultra-LEGe detector was used to count the characteristic X-rays emitted from the samples and from the source. At 14.93, 17.44, and 23.10 keV energies, the mass attenuation coefficients of Cu-Ag thin-film alloys increased with increasing Cu concentration, while decreasing with increasing Cu concentration at 27.37, 32.068, and 48.82 keV energies. However, at 14.93, 17.44, and 23.10 keV energies, the mass attenuation coefficients decreased with increasing Ag concentration, while increasing with increasing Ag concentration at 27.37, 32.068, and 48.82 keV energies. The obtained results were compared with the values theoretically predicted by XCOM, and the experimental results are in good agreement with theoretical values within the error limits.
10.1007-BF02570253	-1		This paper discusses the distribution of thermoelectric inhomogeneity of thermocouple wire dilute magnetic alloy CuFe along the length with a stationary ergodic random model. In the experiment, the principle of the two-media method is used to continuously measure the thermoelectric potential of IH of alloy wire CuFe (O 0.2mm) under normal and repeated low temperature impact conditions with the moving speed of the alloy wire at 4.8mm/s.
10.1007-BF02586158	-1		A new series of Cu-Cr-Zr alloys to be used as railway contact wire, Cu-0.26 wt pet Cr-0.15 wt pet Zr, Cu-0.13 wt pet Cr-0.41 wt pet Zr, and Cu-0.34 wt pet Cr-0.41 wt pet Zr, were studied. The results indicated that processing and aging treatment had an effect on the microstructure, tensile strength, and electrical conductivity behavior of the Cu-Cr-Zr alloys. Process I (solution treatment + cold work + aging) was superior to process II (cold work + solution treatment + aging), because precipitation can occur heterogeneously at the dislocations and subcells. An appropriate processing and aging treatment may improve the properties of the alloys due to the formation of fine, dispersive, and coherent precipitates within the matrix. It is demonstrated that the best combination of tensile strength and electrical conductivity, on the order of 599 MPa and 82 pet IACS (International Annealed Copper Standard), respectively, can be obtained in alloy Cu-0.34 wt pet Cr-0.41 wt pet Zr in the solution-heat-treated, cold-worked, and aged condition. The mechanism of tensile and conductive properties of Cu-Cr-Zr alloy is also discussed.
10.1007-BF02649754	-1		It is now well established that cavities are often formed during superplastic deformation. However, experimental investigations suggest important differences in the nature of the cavitation in typical superplastic metals and ceramics. These differences are demonstrated with reference to a superplastic Cu-based alloy and yttria-stabilized tetragonal zirconia (Y-TZP). By using a quantitative metallographic procedure and scanning video images, measurements are presented showing the size, shape, and configuration of internal cavities in these two materials after deformation at high temperatures.
10.1007-BF02665803	-1		Order-N calculations of the electronic states of models of random substitutional Cu-Zn alloys have been carried out. By analyzing the results, new general features that are characteristic of the Coulomb energies of alloys have been discovered. This article shows how they compare with other models of alloys that have been discussed in the literature. The most important consequence of these calculations is the new insight that they give into the nature of the Coulomb energy in the density functional theory.
10.1007-BF02665813	13	clusters; atomic; glass; atoms; composition; dynamics; metallic; icosahedral; glasses; simulations; molecular; cu-zr; molecular dynamics; metallic glasses; structural	Ternary alloys constitute an important and interesting laboratory for studying electronically driven ordering in alloys because (in contrast to binary alloys) the composition and electron-per-atom ratio (e/a) may be varied independently. Using their recently developed first-principles theory of atomic short-range order (ASRO) in alloys with an arbitrary number of components, the authors discuss ASRO in the ternary Cu-Ni-Zn system, Fermi-surface nesting is found to drive the ordering tendencies of the fee portion of the phase diagram, yielding ASRO whose dominant wave vector varies with e/a in a predictable manner, The authors' concentration-fluctuation theory yields both the wave vector and polarization of the concentration wave, necessary to fully specify the ASRO in an alloy of more than two components.
10.1007-BF02704322	-1		This paper reports results of investigations carried out on a cast copper alloy containing 8 at% Al. The alloy, and pure copper for the sake of comparison, were subjected to cold rolling with a final reduction of 30, 50 or 70%. The cold rolled copper and copper alloy samples were isochronally and isothermally annealed up to the recrystallization temperature. The hardness, strength and electrical conductivity were measured and X-ray and DSC analyses performed. Anneal hardening effect was observed in the alloy in the temperature range 180-300degreesC, followed by an increase in the electrical conductivity. The amount of strengthening increases with increasing degree of prior cold work. The X-ray analysis shows a change in the lattice parameter during annealing when anneal hardening effect was observed. The DSC analysis shows the exothermic character of this effect.
10.1007-BF02708488	-1		The thermal conductivity (TC) of peak aged Cu-4.5 wt% Ti alloy was measured at different temperatures and studied its variation with temperature. It was found that TC increased with increasing temperature. Phonon and electronic components of thermal conductivity were computed from the results. The alloy exhibits an electronic thermal conductivity of 4645 W/m(.)K at room temperature. The phonon thermal conductivity decreased with increasing temperature from 17.6 at 0 K to 1.75 W/m(.)K at 298 K, which agrees with literature that the phonon component of thermal conductivity is insignificant at room temperature.
10.1007-BF02735019	-1		This article presents a detailed investigation on the influence of the phosphorus element upon the laser sintering of a multicomponent Cu-based metal powder system consisting of Cu, Cu-10Sn, and Cu-SAP. Powder systems containing 0, 10, 15, and 20 wt pet CuP were sintered in atmosphere at room temperature using the following optimal processing parameters: laser power of 350 W, scan speed of 0.04 m/s, scan line spacing of 0.15 mm, and layer thickness of 0.25 mm. It was found that the relative density of the sintered sample with 15 wt pet CuP increased by 24.4 pct as compared with the sample without phosphorus addition. A further increase in the CuP content (>= 20 wt pct), however, resulted in a poor densification with a serious delamination. The exact metallurgical roles of the phosphorus element in the laser sintering process were addressed as follows. First, the phosphorus could prevent the sintering system from oxidation by forming CuPO3, thereby improving the wetting characteristics and the sintering kinetics. Second, the phosphorus could decrease the surface tension of molten materials, leading to a successive transition from highly discontinuous sintered tracks to fairly coherent ones with increasing the phosphorus content. Third, the phosphorus could lower the melt viscosity, thereby improving the microstructural homogeneity of the laser-sintered samples.
10.1007-BF02744629	-1		Nanocrystalline Al3Ni, NiAl and Ni3Al phases in Ni-Al system and the alpha, beta, gamma, epsilon and deformation induced martensite in Cu-Zn system have been synthesized by mechanical alloying (MA) of elemental blends in a planetary mill. Al3Ni and NiAl were always ordered, while Ni3Al was disordered in the milled condition. MA results in large extension of the NiAl and Ni3Al phase fields, particularly towards Al-rich compositions. Al3Ni, a line compound under equilibrium conditions, could be synthesized at nonstoichiometric compositions as well by MA. The phases obtained after prolonged milling (30 h) appear to be insensitive to the starting material for any given composition > 25 at% Ni. The crystallite size was finest (similar to 6 nm) when NiAl and Ni3Al phases coexisted after prolonged milling. In contrast, in all Cu-Zn blends containing 15 to 85 at% Zn, the Zn-rich phases were first to form, and the final crystallite sizes were coarser (15-80 nm). Two different modes of alloying have been identified. In case of NiAl and Al3Ni, where the ball milled product is ordered, as well as, the heat of formation (Delta H-f) is large (> 120 kJ/mol), a rapid discontinuous mode of alloying accompanied with an additive increase in crystallite size is detected. In all other cases, irrespective of the magnitude of Delta H-f, a gradual diffusive mode of intermixing during milling seems to be the underlying mechanism of alloying.
10.1007-BF02830336	-1		An anomalous phenomenon has been found in a Cu-Be alloy during an investigation of the aging behavior. A platelike testpiece of a cold-rolled Cu-Be alloy (Japanese Industrial Standard No. C1720) was held at 1073 K for 2 hours, followed by quenching to solutionize. The testpiece was set in a hand-made cantilever jig and aged by applying an external stress with a screw at the free end of the cantilever. The free end of the cantilever leaves the screw in 30 minutes and warps further, within 1 hour, during aging. The spontaneous warping deflection is closely related to the hardness change through aging and is dependent upon the elastic strain introduced initially by the external load. Transmission electron microscope (TEM) observation makes clear that matastable gamma' precipitates, which bring about the most effective hardening and shrinkage, are predominant at the compression side of the cantilever, while extremely fine Guinier-Preston (G-P) zones are observed at an early stage of aging and coarse gamma -phase precipitates are observed at a prolonged aging time in the tension side. The spontaneous warping results from the difference of the precipitation sequence between the two sides.
10.1007-BF02880143	-1		The stress-induced martensitic transformation and its relation with crack nucleation and propagation in CuNiAl shape memory alloy were investigated through in-situ tensile tests by SEM and TEM. The results indicated that the stress concentration ahead of the crack tip could induce formation of stacking faults and different types of martensites. TEM observations showed that the martensites could transform from one type to another and even reversely to the parent during loading. The microcracks nucleated along the martensite/parent interface and intersection between two martensites. When, the crack propagated a certain distance, the stress concentration ahead of the crack tip was large enough to result in formation of slip bands, and in this condition the microcrack nucleated along slip bands more easily.
10.1007-BF02884656	0	solidification; phase; magnetic; magnetic field; undercooling; field; liquid; separation; peritectic; immiscible; cu-; dendrite; phase separation; microstructure; primary	Supercooling directional solidification (SDS) is put forward by combination of melt supercooling and conventional solidification by application of supercooling inheritance. On the self-designed SDS equipment, SDS of Cu-Ni alloy was achieved successfully. The results are as follows: (i) The primary arm spacing is about 30 mu m, the growth of secondary arms are strongly suppressed. The primary arm spacing is nearly the same as LMC method (G(L)=25 K/mm, V=500 mu m/s), the primary stems are straight, fine and completed, with an inclination angle of about 5.8 degrees. (ii) A semi-quantitative T-T model is brought forward to describe the dendrite growth rate V vs. undercooling Delta T. The prediction of T-T model agrees well with experimental results. The formation of fine equiaxed dendrites, transition region and dendrite region can be explained successfully by Delta T-V-x relation of T-T model.
10.1007-BF03027421	11	glass; bulk; metallic; bulk metallic; gfa; bmg; glassy; metallic glass; ability; bulk metallic glass; amorphous; addition; crystallization; mm; glass-forming	The thermal stability and glass forming ability of Cu50-xZr43Al7Agx (x=0, 1, 3, 5, and 7) bulk metallic glass alloys have been investigated. The glass forming ability in the Cu-Zr-Al-Ag alloys increased proportionally to the Ag content and show good correlations with thermal parameters such as DeltaT(x)(=T-x-T-g), T-rg(=T-g/T-l) and gamma(=T-x/(T-g+T-l)). For the Cu43Zr43Al7Ag7 alloy, fully amorphous rods of 8 mm diameter were successfully fabricated by copper mold casting. Mechanical tests on this composition revealed also remarkable properties with compressive strength around 2000 MPa and large ductility.
10.1007-BF03027487	-1		Cu-Ag-Zr alloy has an excellent combination of mechanical strength and electrical conductivity, and is a promising contact wire material for high-speed electrified railways. An investigation of the electritrobological behavior of Cu-Ag-Zr wire is presented here. Wear tests are conducted under laboratory conditions with a specified sliding wear tester that simulated train motion under an electrical current applied across the sliding interface. The Cu-Ag-Zr alloy wire is slid against a copper-based powder metallurgy strip used in railway systems under unlubricated conditions. Worn surfaces of the Cu-Ag-Zr alloy wire are analyzed by scanning electron microscopy (SEM) and energy dispersive X-ray spectrum (EDS). Within the studied range of electrical current, normal pressure, and sliding speed, the wear rate increases with increasing electrical current and sliding distance. Adhesive wear, abrasive wear, and electrical erosion are the dominant mechanisms during the electrical sliding processes. Compared with a Cu-Ag contact wire under the same test conditions, the Cu-Ag-Zr alloy wire has much better wear resistance.
10.1007-BF03027819	-1		By means of a vacuum induction furnace, a Cu-Ag-Cr alloy was produced. The electrotribological property and mechanism of the Cu-Ag-Cr alloy wear studied via wear property tests, scanning electron microscope (SEM), energy dispersive X-ray spectrum (EDS) and transmission electron microscopy (TEM). Wear tests were conducted with a specially designed sliding wear tester, which simulated the tribological conditions of sliding current collectors on contact wires in a railway system. The alloy wire was slid against a copper-based powder metallurgy strip under non-lubricated conditions. The results showed that the wear rate Of Cu-Ag-Cr alloy increases as the sliding speed increases under a normal load. Adhesive wear, abrasive wear, and electrical erosion wear are the governing wear mechanisms under the electrical current sliding processes. Under the same conditions, the wear resistance of the Cu-Ag-Cr alloy is 2-3 times that of the Cu-Ag alloy.
10.1007-BF03166305	-1		Quadrupole effects in room-temperature continuous-wave (CW) Cu-63 nuclear magnetic resonance (NMR) spectra, pi/2 pulse length shortening and amplitudes of two-pulse generated echoes were investigated on nanocrystalline copper powders produced by cryogenic melting and by ball milling techniques. Systematic measurements on the parent polycrystalline copper and on copper-based copper-palladium dilute alloys on the basis of the same experimental techniques were also made and the results were compared to that of the nanophase samples. Fractions of Cu nuclei contributing to the specific NMR responses and average field gradients coming from noncubic neighborhoods were estimated in all the investigated cases. The satellite and/or central component origins of NMR spectra of the samples are not a priori trivial even in the simplest case. Comparative analysis of CW and pulsed experiments allowed a surprising technological conclusion to be drawn by finding a smaller chemical impurity content inside the nanograins than the value characteristic of the entire sample. The measured decrease of the impurity concentration in the inner region of the copper nanoparticles is the consequence of the applied technologies: cryogenic melting and ball milling. These preparation methods cause grain-boundary segregation and result in a cleaner inside of copper nanoparticles.
10.1007-BF03185979	4	transformation; martensite; martensitic; phase; shape; beta; memory; shape memory; temperature; temperatures; martensitic transformation; gamma; transformation temperatures; effect; thermal	The flame quenching process has been employed to modify the surfaces of a commercial marine propeller material, aluminum bronze alloy (Cu-9Al-5Ni-5Fe), and the material's microstructure and. hardness properties have been studied. The thermal history was accurately monitored during the process at various surface temperatures and holding times. XRD and EDX analyses have shown that above T-beta temperature the microstructure consisting of alpha and kappa phases changes into alpha and beta' martensite due to an eutectoid reaction of alpha + beta-->kappa and a martensitic transformation of beta-->beta'. The beta' martensite phase formed has a face-centered cubic (FCC) crystal structure with typical twinned structure. The hardness of the flame-quenched layer having the alpha + beta' structure is similar to or lower than that of the alpha + kappa structure, depending highly on the size and distribution of beta' and kappa phases. It is noted that the sliding wear resistance of the flame-quenched layer is enhanced with the formation of beta' martensite.
10.1007-s00161-006-0038-1	-1		Modeling the energetic behavior of martensitic (phase transforming) materials usually leads to non quasiconvex energy formulations. For this reason, researchers often employ quasiconvex relaxation methods to improve the character of the formulation. Unfortunately, explicit expressions for the relaxed free energy density for multi-variant martensitic materials are typically not available. Thus, some researchers have employed a Reu beta-like convex lower bound, which neglects compatibility constraints, as an estimate on the free energy of mixing. To be confident with such a technique, one needs a measure of the quality of the lower bound. In this paper, we seek such a measure by comparing the Reu beta-like lower bound to an upper bound. The upper bound is constructed upon assumptions on the type of microstructures that form in such alloys. In particular, we consider lamination type microstructures which form by temperature- or stress-induced transformation in monoclinic and orthorhombic Copper-based alloys with cubic austenitic symmetry. Our results display a striking congruence of upper and lower bounds in the most relevant cases.
10.1007-s00170-009-2304-4	-1		Tungsten-Copper (W-Cu) alloys are promising materials for electrical and thermal applications. However, its forming method still remains limited in conventional powder metallurgy technique which is not suitable for manufacturing parts with intricate shapes. In this work, selective laser melting technology was introduced for fabricating W-10 wt% Cu alloys parts. The morphological feature of a single molten track was analyzed. The results show that liquid phase sintering with complete melting of the binder (Cu), but nonmelting of the structural metal (W), acts as the main mechanism in this process. The melting conditions of single layers in different processing parameters were investigated. The results show that a moderate melting zone can be acquired from an established process map. Moreover, investigations on multilayers forming show that the final density increases with the decrease of scan speed until it reaches a plateau due to the insufficient rearrangement in liquid phase sintering and the balling effect.
10.1007-s00170-012-4454-z	16	wear; composite; composites; powders; milling; particles; powder; wt; sliding; friction; hardness; matrix; mechanical; surface; properties	White layer thickness (WLT) formed in electrodischarge drilling (EDD) of beryllium-copper (Be-Cu) alloy and the variation of WLT with respect to drilling depth has been studied in detail by this work. An empirical model relating to EDD process parameters (the working current and pulse on-/off-time) has been developed to predict the WLT at various hole depths. Experimental results were statistically analyzed using analysis of variance (ANOVA) and Tukey's honestly significant difference methods. It was found that the white layer thickness increases with increasing drilling depth as well as the working current and the pulse duration. While the effect of EDD parameters on the variation of the WLT is around 38-39 %, the effect of the hole depth on the variation of the WLT is 17 %. The developed second order mathematical stochastic model for the WLT has an adequate predictive ability.
10.1007-s00170-014-6689-3	-1		In order to achieve rapid manufacturing of tungsten-copper alloy part, copper alloy parts (CuW, CuSn, CuP, with mass ratio of 1:2:2) were manufactured by selective laser melting (SLM), and the influence of different energy input was investigated. The methodology of separating part model was adopted to overcome the manufacturing defects that was caused by the scanning strategy. The results shown that the thicknesses of the thin walls gained by SLM vary from 123 to 276 mu m with the laser power varying from 100 to 120 W and the scanning speed of 200 to 700 mm/s. The compartment walls obtained through separating part model were of uniform thicknesses and nonclogging pores. It provides a feasible method for manufacturing precise parts containing tungsten and mass manufacturing of precise microcomponents by the SLM process.
10.1007-s00170-015-7098-y	16	wear; composite; composites; powders; milling; particles; powder; wt; sliding; friction; hardness; matrix; mechanical; surface; properties	Cold pressed mechanically alloyed Cu-1Zr (wt%) and Cu-4.1Zr-1.1B (wt%) powders were sintered by laser irradiation. Laser employed was pulsed, millisecond Nd:YAG laser system. The influence of different sintering parameters on structural, mechanical, and physical properties of laser-sintered materials was investigated. Microstructural changes during laser sintering were studied using scanning electron microscopy and X-ray diffraction. High hardening of the Cu-Zr alloy is achieved by thermal treatment due to the influence of the developed rapidly solidified structure and precipitation of metastable CuZr. In ternary Cu-Zr-B alloy rapidly solidified structure, as well as the presence of ZrB2 particles and metastable CuZr phase, affected much higher degree of copper matrix hardening which, thanks to the ceramic particles, is retained at high temperatures. It was determined that the optimum combination of high density, microhardness, and electrical conductivity is reached using the following parameters: laser frequency 3 Hz, laser pulse duration 8 ms, pulse energy similar to 19 J, number of scans 3 (binary alloy), i.e., 4 (ternary alloy).
10.1007-s00170-015-7964-7	-1		Precipitation-hardened Cu-0.804Cr-0.063Zr alloy is a potential material to be used for the fabrication of heat sinks in International Thermonuclear Experimental Reactor (ITER) applications. The softening temperature of these alloys is 500 A degrees C, which makes it suitable for the fabrication of components subjected to high heat flux. During welding, the precipitates get completely dissolved in the melted zone, which results in lower hardness and softening temperature. The aim of this study was to understand the effects of electron beam welding (EBW) on weld bead geometry and mechanical properties of this alloy. Accelerating voltage, beam current, welding speed, and focusing distance were selected as input variables, and bead geometric parameters like bead width, bead penetration, and microhardness values of the fusion and heat-affected zones were considered as outputs. Statistical regression analysis was conducted to determine input-output relationships. All the above input parameters were found to have significant contributions toward bead penetration and microhardness of fusion zone. However, accelerating voltage did not have significant contribution toward bead width . Optimization was done to obtain minimum weldment area after satisfying the conditions of maximum bead penetration and minimum deviation of the hardness of fusion zone from that of parent material. This constrained optimization problem was solved using a genetic algorithm along with a penalty function approach for handling the functional constraints. A good agreement was obtained between the results predicted by the optimization tool and that of real experiments. Thus, the genetic algorithm (GA) could accurately establish input-output relationships of this process.
10.1007-s00170-016-8551-2	-1		The purpose of this study is an attempt to obtain nanocrystalline bulk Cu-40 at% Fe alloy by mechanical alloying followed by consolidation process under 7 GPa and annealing. The transformations occurring in the material were studied by the use of X-ray diffraction. The structural investigations revealed that consolidation enabled supersaturated Cu(Fe) to precipitate out Cu4Fe and CuFe4 intermetallics. A limited grain growth was noticed after annealing. The results of microhardness have shown that the hardening increases similarly up to 40 h milling. The variation of microhardness as a function of the reciprocal square root of the grain size demonstrates that the rate of hardening is similar to that predicted by the Hall-Petch behavior.
10.1007-s00170-016-9658-1	-1		Equal channel angular pressing (ECAP) is one of the most prominent severe plastic deformation (SPD) processes to achieve ultra-fine grained (UFG) structures. Using bimetallic specimens has been recently considered in this process. In the present study, the effects of casing with lower strength, compared to the billet, and the casing thickness on mechanical properties of ECAPed billet are investigated experimentally and by simulation. Bimetallic specimens of pure Cu and Al-7075 alloy with different dimensions are ECAPed in one pass at room temperature. The effect of casing and its thickness on the required forming load, the average amount of equivalent plastic strain and Vickers micro-hardness, and their distributions in cross section of billet, strain homogeneity, compression strength of billets, and stress distribution in the deformation zone are investigated.
10.1007-s00170-017-0220-6	-1		The current trend to replace cobalt in diamond cutting tools (DCTs) for stone cutting has motivated the study of alternative materials for this end. The present study evaluated the performance of several diamond-reinforced copper-nickel composites as regard to their suitability for serving as stone cutting materials. Cobalt (Co) and copper-nickel composites (Cu-Ni; Cu-Ni-10Sn, Cu-Ni-15Sn, Cu-Ni-Sn-2WC, and Cu-Ni-Sn-10WC) reinforced with 4 wt% of diamond particles were produced by hot pressing, at a temperature of 850 A degrees C during 15 min and under an applied pressure of 50 MPa. The obtained specimens were characterized in terms of Vickers hardness and shear strength . The microstructure was analyzed by the means of SEM/EDS. A pin-on-disc wear test, with the composite serving as pin and a stone serving as disc, was performed in order to assess the tribological properties and cutting performance. Cu-Ni-Sn-10WC showed to be the material with the best cutting properties, with the highest disc/pin wear ratio registered among the remaining competing materials. This material arises as a promising alternative to be used in the stone cutting industry.
10.1007-s00170-017-0714-2	-1		In order to improve the performance of metal-bonded grinding wheels, the graphite particles with several different contents (i.e., 5, 10, 15, and 20 wt%) were added to Cu-Sn-Ti alloy powders as the bonding materials. The influence of graphite addition on bonding properties of the abrasive layer was investigated. Firstly, microstructural examination results show that the joining between graphite and Cu-Sn-Ti alloy was achieved and provided a weak bonding strength compared to the pure Cu-Sn-Ti matrix. Secondly, the transgranular fracture and intergranular fracture were determined as the main fracture patterns of abrasive layer in the current investigation. Then, an optimized graphite content of 10 wt% was decided, at which the porosity of abrasive layer can reach 25% as well as the bending strength reached 125 MPa and was favorable to meet the high-speed grinding requirements. Finally, the finite element simulation results suggested that the graphite addition had little effect on the residual thermal stresses of abrasive layer.
10.1007-s00170-018-1891-3	-1		In this work, Cu-15Ni-8Sn components were manufactured by selective laser melting (SLM) with a near full density of about 99.4%. The microstructures and phase precipitation of the as-fabricated Cu-15Ni-8Sn alloy were characterized by X-ray diffraction (XRD), electron probe microanalyzer (EPMA), electron back-scattered diffraction (EBSD), and transmission electron microscope (TEM). It was demonstrated that the as-fabricated Cu-15Ni-8Sn alloy shows alpha-phase with gamma-precipitates by XRD and TEM. The size of the grains of alpha-phase is in the range of 5 similar to 20 mu m with random orientation distribution. The gamma-precipitate is a Sn- and Ni-rich phase distributed dispersedly in matrix and accumulatively in grain boundary. The as-fabricated Cu-15Ni-8Sn alloy exhibited yield strength of 522 MPa, ultimate tensile strength of 653 MPa, and elongation of 17%. The excellent mechanical performance of the as-fabricated Cu-15Ni-8Sn alloy is caused by the local laser melting mode including rapid cooling rate and reduplicative fusing from the subsequent layer melting, which leads to refined grains and limited Sn segregation in micron-size within the matrix.
10.1007-s00170-018-2477-9	-1		Based on the coupling method of finite element method and smoothed particle hydrodynamics method, the process of single abrasive grain cutting particles reinforced Cu-matrix composites with small volume fraction of particle phase is simulated, and the chip formation mechanism of particle reinforced Cu-matrix composites was analyzed. It can be concluded that the plastic removal of the Cu-matrix is still the main removal form of the composite, but the existence of the reinforced particle phase affects the cutting deformation behavior and the chip morphology. During the cutting process, the interfaces between part of reinforced particles and the Cu-matrix are broken, and resulting in the particles falling off into chips, but most of the particles will form continuous mixed chips with copper alloy, with the plastic deformation of the Cu-matrix. The extrusion of abrasive particles leads to pile-up of dislocation producing in Cu-matrix around the reinforced particle, which interferes with the continuous plastic deformation of Cu-matrix, thus affects the cutting force and cutting temperature of the abrasive grain. The simulation results show that with the increase of cutting speed, the cutting force decreases, but the cutting temperature increases. As the cutting depth increases, the cutting force and cutting temperature increase. The increase of reinforced particle content will lead to the increase of cutting force and cutting temperature.
10.1007-s00170-019-03419-5	2	corrosion; surface; film; electrochemical; films; spectroscopy; layer; current; solution; potential; resistance; composition; x-ray; ions; showed	Jet electrodeposition is an advanced manufacturing technology that can produce metallic nano-scaled microstructures with unique performance. Cu-Al2O3 composite coatings were prepared by jet electrodeposition from a plating bath with nano-Al2O3 particles suspended into the bath . Detailed microstructure changes upon the changes of experimental conditions were characterized using X-ray diffraction (XRD) and scanning electron microscope (SEM). The effect of the deposition conditions on the composite coating mechanical properties was investigated. Experimental results indicated that the Al2O3 particle adding into the electrolyte was able to refine the composite coating grains and enhance the deposit inner-structure as well as compactness, which considerably strengthens the composite coating's mechanical property. It is proved that the current density in the range of 100 similar to 500 A/dm(2) could offer grain refining effect and the addition of Al2O3 nanoparticles can effectively promote the composite coating mechanical properties.
10.1007-s00170-019-04015-3	-1		The demand for additive manufacturing (AM) of Cu and its alloys shows an increased trend from the energy and heat transfer-related applications. Selective laser melting (SLM) is amongst the key AM processes for metals, providing high geometrical accuracy and design flexibility. The technology is most commonly employed using high-brilliance fibre lasers operating at 1 mu m. However, the elevated reflectivity of Cu at this wavelength, combined with its high thermal conductivity, is the cause for a highly unstable process, whereby pore-free products are difficult to obtain. Accordingly, the present work explores the limitations in processing pure Cu powders with a 1-kW single-mode fibre laser providing solutions and different strategies for improving part quality. The process parameters were studied for single and multi-pass melting strategies. The power level requirements, as well as the build plate material, are assessed through an analytical model. The results demonstrate that a correct sequence of-multi-pass strategies can improve the part density up to 99.1% +/- 0.2% with an industrially acceptable build rate of 12.6 cm(3)/h .
10.1007-s00170-019-04602-4	-1		KOBO extrusion of metals and alloys strongly activates the point defect generation processes, as a result of which they reach a concentration exceeding the equilibrium level by many orders of magnitude. This leads to significant acceleration of diffusion phenomena which in heat-treatable alloys may cause disturbance of the thermodynamic equilibrium between the solid solution decomposition and dissolution of precipitates. In this work, measurements of mechanical and electrical properties and structural observations Cu1Cr0.1Zr alloy subjected to low-temperature KOBO extrusion at different stages of multi-variant heat treatment were conducted. In addition, the geometry of the extruded alloy's flow zone was analyzed and the obtained results made it possible to assess the effectiveness of experimental procedures, including product formation with high extrusion ratio lambda, aimed at achieving of high and thermally stable functional properties of the material.
10.1007-s00170-020-05644-9	-1		One of the exciting applications of laser directed energy deposition (LDED) is the fabrication of complex-shaped engineering components involving graded composition. In the present work, a 2 kW fibre laser-based LDED system is used to deposit copper-nickel (CuxNi(100-x)(x = 25, 50, and 75)) layers on copper (Cu) substrate. The single tracks are deposited at different combination of laser power, scan speed, and Cu-Ni compositions. Track geometry (width and height) indicates direct and inverse dependence with laser power and scan speed, respectively. For same LDED processing parameters, there is lower track height and wider track width with increasing Cu in Cu-Ni composition due to improved wettability. Further, analysis of variance (ANOVA) shows that laser power and scan speed are more significant for track width and track height, respectively. Graded bulk structures built at identified process parameters are characterized using optical microscopy, microhardness, and single cycle automated ball indentation (SC-ABI). Deposited Cu-Ni graded bulk has a density of > 99% with pure Cu and Ni phase. The microscopy analyses reveal defect-free deposition with fine dendritic growth in the bottom and middle layers, while equiaxed grains are observed in top layers. Microhardness measurements show a smooth hardness transition from deposit to the substrate with higher hardness. SC-ABI presents an increase in energy storage capacity by 2.25 times with the increase in Cu percentage. This work paves a way for fabricating Cu-Ni graded components for manufacturing engineering components.
10.1007-s00170-021-06889-8	16	wear; composite; composites; powders; milling; particles; powder; wt; sliding; friction; hardness; matrix; mechanical; surface; properties	Composites are a unique class of materials extensively used in many modern applications such as aerospace, automobile, and marine applications. However, the high strength and hardness, low thermal expansion, and other physical properties limit its application in machining sector. Therefore, the aim of this study is to investigate the effects of different machining parameters on surface roughness, tool wear, cutting temperature, and chip formation while turning Cu/Mo-SiCp composites. The copper composites reinforced with Mo-SiCp were fabricated with powder metallurgy route and depth of cut (a(p)), feed rate (f(n)), and cutting speed (V-c) were selected as the machining parameters. Influence of each parameter was noticed with 3D surface plots and scanning electron microscope observations were used for wear analysis. At the end of the analysis, it was determined that the most important parameter affecting surface roughness, tool wear, and cutting temperature was particle additive ratio. In addition, it was observed that chip types and wear types changed according to increasing reinforcement rates.
10.1007-s00170-022-10346-5	16	wear; composite; composites; powders; milling; particles; powder; wt; sliding; friction; hardness; matrix; mechanical; surface; properties	Spark plasma sintering (SPS) in situ degassing process of copper reinforced with TiC powder was examined on densification and wear behavior of copper and copper composite samples. Pure Cu and Cu-10 vo l%TiC, Cu-15vo l%TiC, and Cu-20 vo l%TiC were fully densified by degassing the powder from 25 to 550 degrees C and then sintered from 550 to 650 degrees C. The influence of the sintering process on the microstructure, phase change, densification, hardness, and wear was investigated. A relative density of 98.5% and 98.8% was obtained in Cu and Cu reinforced with 15 vo l%TiC, respectively. The XRD pattern did not reveal a copper oxide phase. The fracture surfaces show a strong interfacial bonding of TiC with the copper matrix. The Vickers hardness of 140.5 +/- 5.03 HV0.3 was obtained in Cu-15 vo l%TiC composite. The wear tests were done under dry sliding conditions at varying loads (5, 10, 15, and 20 N). The frictional coefficient of Cu was enhanced with TiC contents.
10.1007-s00170-023-11150-5	5	materials; thermal; heat; properties; material; welding; sintering; fusion; strength; laser; heat sink; thermal conductivity; mechanical; sink; manufacturing	Fabrication of metallic solid objects was achieved using an experimental spiral growth selective laser melting (SG-SLM) 3D printer. This device incorporates a cylindrical coordinate system, thus coined spiral growth manufacturing (SGM), instead of the ubiquitous Cartesian coordinate system found in commercial powder bed fusion selective laser sintering/melting (SLS/SLM) equipment. How the fabrication parameters, laser beam power, and powder layer thickness affect the properties of the resulting 3D printed parts are addressed by assessing the volumetric energy density of each parameter set. This magnitude is then correlated with the mass rate efficiency and physical and mechanical properties of printed ring-shaped objects. A design of the experiment was set up varying the thickness of the powder layer from 400 to 600 mu m and the nominal laser beam power between 150 and 250 W; the rpm used was set to 1. The experiments were carried out using a commercial powder copper alloy processed under flowing argon gas. Results show a decreasing trend between the mass rate efficiency and the volumetric energy density; moreover, an increase in the mass density of the specimens with volumetric energy density is observed; however, a decrease in ultimate stress is witnessed instead. Microhardness is almost independent of volumetric energy density while % porosity slightly increases with the latter. Current work is underway to achieve a lower layer thickness below 100 microns.
10.1007-s00170-023-11672-y	5	materials; thermal; heat; properties; material; welding; sintering; fusion; strength; laser; heat sink; thermal conductivity; mechanical; sink; manufacturing	Comparisons between virtual prototyping and experimental results are notably beneficial for the development of investment casting processes. In this research, such a comparison aimed to study the castability of a Cu-Al-Mn shape memory alloy (SMA) in a modified centrifugal investment casting process that uses centrifugal force to inject the molten metal into the mold. Virtual prototyping was numerically simulated using the ProCAST software applying a rectangular mesh part design. The real and virtual parts were examined for mold filling (castability), pore formation, and solidification time. Using Whitlook's methodology, it was possible to validate the model created in the ProCAST software to simulate the modified investment casting process, detecting results regarding filling, solidification, and porosity with a high degree of accuracy and reliability. In addition to the validation of the developed model, this work also presents estimated values for interface heat transfer coefficient (IHTC) of the metal/mold of aluminum bronze (Cu-Al and Cu-Al-Mn) alloys poured by gravity and centrifugation into plaster molds. Among the obtained values, the IHTC for the 86.7Cu-7.9Al-5.4Mn SMA were estimated at 535 W/m(2) K when poured by centrifugal force and 75 W/m(2) K by gravity. Ultimately, it was possible to verify that Cu-Al-based shape memory alloy presents a high castability and a low cooling rate.
10.1007-s00170-023-11728-z	14	strength; properties; conductivity; electrical; mechanical; cu-; grain; mpa; electrical conductivity; aging; precipitation; phase; mechanical properties; tensile; phases	This research explores the impact of Cu composition, heating temperature, and milling time on the production of copper-tin alloy nanoparticles. By employing design of experiments techniques, the study systematically evaluates these input variables and their effects on particle size, optical density, and number of colonies. The identification of new Cu3Sn phases in the nanoparticle structure contributes to the novelty of this research . The findings highlight the potential for optimizing copper-tin alloy nanoparticle synthesis and enhancing their antibacterial properties. Mechanical alloying is found to produce nanoparticles up to 15 nm in size. Increasing the percentage of copper leads to improved antibacterial properties. This work provides insights into the synthesis process of copper-tin mechanical alloying and their potential for antibacterial applications.
10.1007-s00170-023-12179-2	-1		The Cu-Cr-Zr alloy has an important role in the domain of thermonuclear fusion and electronic applications. But due to their higher thermal conductivity and reflectivity, the laser powder bed fusion (LPBF) manufacturer faces many defect formations such as balling effects, spattering effects, and un-melted powders during the fabrication of Cu-Cr-Zr alloy. However, these defect formations can be reduced by analyzing and evaluating the interactions of parameters. In this research, a correlation of LPBF process parameters such as laser power (250, 350, and 450 W), scan speed (750, 850, and 950 mm/s), and hatching distance (0.05, 0.07, and 0.09 mm) was investigated to achieve defect-free Cu-Cr-Zr parts with reduced porosity and surface roughness with maximum nanohardness. The combined analytical approach based on integrated entropy and Deng's similarity validated the experimental study. Major defects such as cavity formation, lack of fusion between the layers, and improper melting of Cu-Cr-Zr powder particles were evident during the reduced energy density of around 100 to 200 J/mm(3) during the adoption of a minimum laser power of around 250 to 300 W. The outcome shows that defect-free parts with reduced porosity of 0.88%, reduced surface roughness of 23.24 & mu;m, and maximum nanohardness of 5.2 GPa were achieved during the optimal setting of 450 W laser power, 850 mm/s scan speed, and 0.05 mm hatching distance. LPBF Cu-Cr-Zr alloy with optimal combination offers 278.92 MPa in ultimate tensile strength and 11.69% in ductility. The optimal settings obtained from the experimental study are in greater agreement with the integrated entropy and Deng's similarity approach .
10.1007-s00170-023-12874-0	-1		For a past few years, laser powder bed fusion (LPBF) process faced many issues such as cavity creation, unstable thermal capillary convection, and thermodynamic instability during the printing of Cu-Cr-Zr alloy. Hence, the important LPBF process variables such as exposure duration (ED) of 300, 400, and 500 mu s; laser power (LP) of 370, 420, and 470 W; and overlapping percentage (OP) of 20, 40, and 60% needs to be examined based on the interactions of various combinations of parameters to fabricate a Cu-Cr-Zr alloy parts with reduced porosity, maximum ultimate tensile strength (UTS), and minimum nano-indentation depth (NID). Moreover, analytical studies were also performed based on the COmplex PRoportional ASsessment (COPRAS) approach . The proposed analytical approach shows better concurrence with the experimental observations. The optimal and initial variables obtained from the analytical and experimental approach were compared. The Cu-Cr-Zr alloy printed with optimal parameter settings possesses maximum UTS of 367 MPa and minimum NID of 321.51 nm. These enhanced results were mainly due to the occurrence of reduced porosity of 0.27%. Moreover, FESEM based fracture mechanism were investigated to study the propagation of cracks based on the defects formation.
10.1007-s00170-024-13883-3	-1		Cu-Cr-Zr alloy's low wear resistance due to defect generation and cavity creation during the laser powder bed fusion (LPBF) process prevents its use in the aerospace and automotive industries. Hence, this research focuses on enhancing the wear resistance by mitigating defect formations during the LPBF process. The key LPBF process parameters such as exposure span (ES) of 350, 550, and 650 mu s; laser power (LP) of 280, 360, and 440 W; and hatching range (HR) of 0.04, 0.07, and 0.1 mm were chosen and examined to reduce the cavity formations and to increase the indentation effect and thereby enhancing the wear resistance of the printed Cu alloy components. Criteria Importance Through Intercriteria Correlation (CRITIC) associated with COmplex PRoportional ASsessment (COPRAS)-based multi-criterion decision-making (MCDM) technique was employed to substantiate the results obtained from the experimental analysis. Comparative analysis was performed for four different combinations of parameters to examine the impact of individual parameters in influencing the wear resistance. The research outcome confirms that the reduced cavity percentage of 0.08% with the minimal wear rate of 0.83 x 10-5 mm3/Nm and maximum nanohardness of 2.82 GPa was attained during the implementation of minimum ES of 350 mu s and HR of 0.04 mm with maximum LP of 440 W. Furthermore, during the examination of wear mechanism, the transformation of adhesion to abrasion wear mode was evident which was induced by the defect formations. However, the mitigation of defect formations was also addressed in this investigation.
10.1007-s00170-024-14618-0	-1		Copper laser powder bed fusion (Cu-LPBF) is known as a challenging manufacturing process. Since copper is an excellent thermal and electrical conductor, low to medium laser power is insufficient to provide good wettability and fusion between either adjacent tracks or deposited layers due to heat dissipation and high reflectivity. Particle surface modification has therefore been proposed to improve optical absorptivity. A simple method to enhance optical absorptivity is to create a thin oxide film by heating copper powder in an air furnace. The first phase of the current work emphasizes that this technique is detrimental to the part quality if a medium laser power range is used. The second phase presents a novel technique of two stages of in-situ copper oxide reduction during LPBF. It provides an innovative approach for combining laser cleaning and melting in LPBF. The newly suggested technique uses recycled and surface oxidized Cu powders to develop a simple and chemical-free method to recover the contaminated powder. A significant improvement is achieved by applying laser surface cleaning to the powder and solidified layers. The oxygen content is reduced by 70% in the LPBF samples compared to the initial state of the oxidized powder.
10.1007-s00170-025-15790-7	-1		The dynamic increase in copper and copper alloy use is closely associated with the search for cathode copper substitutes in various production processes. Within the article, research was carried out on copper scraps in the form of worn-out railway catenaries, which were originally produced from Cu-ETP copper. This article assesses the industrial potential of this kind of scrap for direct use in modern production technologies of copper alloys. However, due to its characteristics, resulting from many years of wear and potential exposure to surface pollution, the assessment of potential use was made based on surface contamination influence on the chemical composition of the base material after melting and solidification (simulation of traditional casting processes). Conducted research works showed that the main contaminants of used traction copper scrap are Fe, Pb, and S and also other elements in trace amounts. The amount of copper contamination detected after direct remelting of worn catenary conductor resulted in a decrease in copper conductivity to the level of 49.3 MS/m (approx. 85% IACS). Moreover, the conducted research revealed that, due to the geometrical structure of the catenary conductor, it is partially possible to recover clean copper, characterized by high electrical conductivity (58.3 MS/m) and low impurity content.
10.1007-s00216-009-3015-2	2	corrosion; surface; film; electrochemical; films; spectroscopy; layer; current; solution; potential; resistance; composition; x-ray; ions; showed	Reference Cu-based alloy with chemical composition and micro-chemical structure similar to that of ancient alloys has been used for carrying out the artificial long-term degradation test based on chloride enriched soil (chemical + soil) degradation. The results show that such degradation procedure produces natural like patinas as the ones grown on archaeological artefacts, from a chemical, structural and micro-morphological point of view. Glow discharge plasma technique has been employed for the treatment of the as-corroded bronze coupons. The gradual elimination of chloride-containing corrosion products in favour of the formation of more stable species and even the complete reduction back to copper has been observed. The chemical and metallurgical features have been determined by combined use of different analytical techniques such as scanning electron microscopy with energy dispersive X-ray micro-analysis (SEM-EDS), X-ray diffraction (XRD) and optical microscopy.
10.1007-s00216-011-5268-9	2	corrosion; surface; film; electrochemical; films; spectroscopy; layer; current; solution; potential; resistance; composition; x-ray; ions; showed	Three bronze samples created by CNR-ISMN (National Research Council-Institute of Nanostructured Materials) to be similar to Punic and Roman coins found in Tharros (OR, Sardinia, Italy) were studied to identify the corrosion products on their surfaces and to evaluate the reliability of the reproduction process. Micro-Raman spectroscopy was chosen to investigate the corroded surfaces because it is a non-destructive technique, it has high spatial resolution, and it gives the opportunity to discriminate between polymorphs and to correlate colour and chemical composition. A significant amount of green copper hydroxychlorides (Cu-2(OH)(3)Cl) was detected on all the coins. Their discrimination by Raman spectroscopy was challenging because the literature on the topic is currently confusing. Thus, it was necessary to determine the characteristic peaks of atacamite, clinoatacamite, and the recently discovered anatacamite by acquiring Raman spectra of comparable natural mineral samples. Clinoatacamite, with different degrees of order in its structure, was the major component identified on the three coins. The most widespread corrosion product, besides hydroxychlorides, was the red copper oxide cuprite (Cu2O). Other corrosion products of the elements of the alloy (laurionite, plumbonacrite, zinc carbonate) and those resulting from burial in the soil (anatase, calcite, hematite) were also found. This study shows that identification of corrosion products, including discrimination of copper hydroxychlorides, could be accomplished by micro-Raman on valuable objects, for example archaeological findings or works of art, avoiding any damage because of extraction of samples or the use of a destructive analytical technique.
10.1007-s00339-004-2934-1	4	transformation; martensite; martensitic; phase; shape; beta; memory; shape memory; temperature; temperatures; martensitic transformation; gamma; transformation temperatures; effect; thermal	A water-quenched martensitic CuAlNi shape-memory alloy was investigated by a combination of coincidence Doppler broadening and positron-lifetime spectroscopy, supported by positron-lifetime calculations. We find a high defect concentration in the as-quenched samples. The positron-lifetime calculations suggest that the defects are not only single vacancies but also vacancies associated with dislocations and stacking faults. Annealing in the martensitic phase has no significant influence on the vacancy concentration but results in a different chemical environment around the vacancies. After aging in the austenitic phase the vacancy concentration decreases significantly.
10.1007-s00339-006-3504-5	2	corrosion; surface; film; electrochemical; films; spectroscopy; layer; current; solution; potential; resistance; composition; x-ray; ions; showed	High-energy synchrotron X-ray diffraction and imaging experiments were performed at the Advanced Photon Source on two ancient Chinese bronzes from the Art Institute of Chicago with the goal to nondestructively study their microstructure. The first object, a bronze fragment from an early Western Zhou dynasty vessel (Hu, 11th/10th century B.C.), was investigated with spatially-resolved diffraction to reveal the depth and composition of the surface corrosion layer as well as the composition and grain size of the underlying bronze core. The second object, a bronze dagger-axe (Ge, 3rd/2nd century B.C.) with a silver-inlaid sheath, was studied under both diffraction and imaging conditions. It was found to have been cast as a single object, answering longstanding scholars' questions on whether the ceremonial object concealed an interior blade.
10.1007-s00339-006-3550-z	2	corrosion; surface; film; electrochemical; films; spectroscopy; layer; current; solution; potential; resistance; composition; x-ray; ions; showed	A large number of Cu-based archaeological artefacts from the Mediterranean basin have been selected for investigation of their chemical composition, metallurgical features and corrosion products (i.e. the patina). The guidelines for the selection of the Cu-based artefacts have taken into account the representativeness of the Mediterranean archaeological context, the manufacturing technique, the degradation state and the expected chemical composition and structure of the objects. The results show wide variation of the chemical composition of the alloys that include all kinds of ancient Cu-based alloys such as low and high tin, and also leaded bronzes, copper and copper-iron alloys. The examination of the alloy matrix shows largely different metallurgical features thus indicating the use of different manufacturing techniques for producing the artefacts. The results of the micro-chemical investigation of the patina show the structures and the chemical composition of the stratified corrosion layers where copper or tin depletion phenomenon are commonly observed with a remarkably surface enrichment of some soil elements such as P, S, Ca, Si, Fe, Al and Cl. This information indicates the strict interaction between soil components and corrosion reactions and products. In particular, the ubiquitous and near constant presence of chlorine in the corrosion layers is observed in the patina of the archaeological Cu-based artefacts found in different contexts in Italy, Turkey, Jordan, Egypt, Spain and Tunisia. This latter occurrence is considered dangerous because it could induce a cyclic corrosion reaction of copper that could disfigure the artefact. The micro-chemical and micro-structural results also show that another source of degradation of the bronze archaeological artefacts, are their intrinsic metallurgical features whose formation is induced during the manufacturing of the objects, carried out in ancient times by repeated cycles of cold or hot mechanical work and thermal treatments. These combined treatments induce crystallisation and segregation phenomena of the impurities along the grain boundaries and could cause mechanical weakness and increase the extent of the inter-granular corrosion phenomena.
10.1007-s00339-006-3807-6	-1		Cu-Ag filamentary microcomposites with various Ag contents, alloying additions and ingot annealing processes were prepared by vacuum casting and cold drawing. The strength and conductivity were measured at different drawing strain degrees. High conductivity tends to connect to low strength for the microcomposites with different Ag content, alloying addition and annealing process. Increasing Ag concentration, adding constituents Zr and Cr, or using low ingot annealing temperature can improve the strength but impair the conductivity. Alloying additions or ingot annealing processes affect the relationships between the strength and conductivity more significantly than that of Ag concentration. The strengthening benefit is mainly from interface obstacle and dispersive precipitation while conducting loss is mainly from lattice distortion and interface scattering. An approximate expression to predict the relationships between the strength and conductivity is deduced from the interface strengthening and scattering model.
10.1007-s00339-007-4259-3	-1		Film sheet resistance measurement was developed to obtain the oxidation kinetics of Cu thin films in the nanometer range. Cu thin films with smooth and homogenous surfaces were prepared by vacuum evaporation. Oxidation behaviour of Cu thin films at low temperatures from 180 degrees C to 260 degrees C in dry air has been studied. The results show that oxidation of Cu thin film follows a parabolic rate law with a considerable low activation energy of 0.57 eV, which is much lower than that reported for bulk Cu and the thick film. The observed rapid oxidation phenomenon may be attributed to the fast diffusion mechanism dominated by the defect-related grain boundary diffusion in thin films.
10.1007-s00339-010-5675-3	2	corrosion; surface; film; electrochemical; films; spectroscopy; layer; current; solution; potential; resistance; composition; x-ray; ions; showed	Selected groups of copper-based artifacts found during archaeological excavations of the necropolis of Colle Badetta-Tortoreto (Teramo, Italy) were investigated in order to determine the chemical composition and metallurgical features of the alloys and the micro-chemical and micro-structural nature of the corrosion products grown during the long-term burial. The investigated Cu-based artifacts were ornamental objects, such as rivets, buckles and small rings that were applied to large belts to form complex patterns with the addition of small and large shaped pieces of amber. The analytical characterization was performed by using different surface and bulk techniques, such as Optical Microscopy (OM), Scanning Electron Microscopy coupled with energy dispersive X-ray micro-analysis (SEM-EDS), X-ray Diffraction (XRD). Results evidenced that the bronze artifacts were produced by casting an unusual high-tin bronze alloy in a ceramic bivalve mould or by using a low tin bronze alloy coated with a thin layer of tin for producing a silver-like appearance. The main alloying elements were corroded to form different stratified structures of different chemical species, such as tin oxides (romarkite and cassiterite), cuprous oxide and copper carbonates (azurite and malachite), dangerous chlorine-based compounds (nantokite and atacamite polymorphs). This evidenced the strict interaction with the soil components and the pH variation of the different areas of the necropolis, as well as the occurrence of post-burial degradation phenomena. These results confirm that SEM-EDS, XRD and OM can be successfully used for studying the corrosion products of archaeological copper-based artifacts in order to identify the corrosion agents and mechanisms and, thereafter, to propose the best reliable tailored strategies for the conservation of these ancient artworks.
10.1007-s00339-010-5725-x	-1		Atom probe and small-angle neutron scattering (SANS) measurements were carried out in order to investigate the chemical composition of (bcc) Cu precipitates in a (bcc) Fe matrix. The ratio of nuclear and magnetic integrated intensities (R-value) found by SANS is compared to a theoretical model which is based on the chemical composition obtained from the atom probe data. Furthermore, density functional theory calculations were performed to derive the magnetic moment per atom and the lattice parameters of the Cu alloys modeled in terms of supercells. The calculated and measured R-values agree rather well suggesting that Fe atoms are incorporated in the Cu precipitates up to concentrations of about 50 at%.
10.1007-s00339-012-7090-4	0	solidification; phase; magnetic; magnetic field; undercooling; field; liquid; separation; peritectic; immiscible; cu-; dendrite; phase separation; microstructure; primary	Applying a melt-fluxing method, a substantial degree of undercooling up to 220 K has been obtained for Cu50Co50 immiscible alloy and the non-equilibrium solidification microstructure is investigated considering the successive processes of undercooling, liquid separation, non-equilibrium and near-equilibrium solidification. For samples undercooled by 62, 79 and 105 K, grain refinement occurs and becomes more serious without the occurrence of liquid separation and peritectic transformation. In contrast, metastable liquid demixing occurs upon the undercooling reaching 125 K, and it proceeds completely with the further increase of undercooling to 188 and 220 K, which can be ascribed to the sufficient time through the immiscible region. After liquid separation, versatile solidification microstructure for Co-rich and Cu-rich regions can be observed due to the different non-equilibrium effect. Moreover, second liquid separation becomes more serious for higher undercooling because of the enhanced immiscible effect. Finally, the solute content of primary Co-rich phase was analyzed with the consideration of solute trapping and liquid immiscible effects, which gives an excellent explanation for the variation of hardness behavior.
10.1007-s00339-012-7450-0	-1		Carbon nanotube reinforced Cu-Ti alloy (CNT/Cu-Ti) composites are fabricated by a powder metallurgical method. The interfacial bonding of CNT/Cu-Ti composites is evidently improved, which is attributed to the formation of a thin layer of TiC at the interface. The thermal conductivity of the composites increases by 7.5 % and 15.1 % compared to that of Cu-Ti matrix at CNT loadings of 5 vol.% and 10 vol.%, respectively. The matrix-alloying is therefore an effective way to enhance the thermal conductivity of CNT/Cu composites.
10.1007-s00339-013-7750-z	2	corrosion; surface; film; electrochemical; films; spectroscopy; layer; current; solution; potential; resistance; composition; x-ray; ions; showed	The paper contributes to the identification of different corrosion products detected on the cross-section specimens sampled from Bronze Age swords and one helmet found between 60-160 years ago. The objects are kept in 1889 built oak showcases at the Natural History Museum Vienna, having suffered unknown restoration treatments. The identified corrosion products not only affect further eventual treatment in conservation science of copper base objects but also contribute to identify the often unknown find context, which is meant to facilitate archaeological interpretation of the Bronze Age weapons. The analyses of the samples were carried out using SEM-EDXS-EBSD and optical microscopy.
10.1007-s00339-013-7839-4	-1		Carbon nanotubes (CNTs) are incorporated into the Cu-Cr matrix to fabricate bulk CNT/Cu-Cr composites by means of a powder metallurgy method, and their thermal conductivity behavior is investigated. It is found that the formation of Cr3C2 interfacial layer improves the interfacial bonding between CNTs and Cu-Cr matrix, producing a reduction of interfacial thermal resistance, and subsequently enhancing the thermal conductivity of the composites. The thermal conductivity of the composites increases by 12 % and 17 % with addition of 5 vol.% and 10 vol.% CNTs, respectively. The experimental results are also theoretically analyzed using an effective medium approximation (EMA) model, and it is found that the EMA model combined with a Debye model can provide a satisfactory agreement to the experimental data.
10.1007-s00339-013-7880-3	4	transformation; martensite; martensitic; phase; shape; beta; memory; shape memory; temperature; temperatures; martensitic transformation; gamma; transformation temperatures; effect; thermal	In this study, the Cu-based shape memory alloys were produced by arc melting. We have investigated the effects of the alloying elements on the characteristic transformation temperatures, enthalpy, entropy values, and the structure of Cu-Al-Mn ternary system. The evolution of the transformation temperatures was studied by the differential scanning calorimetry. The characteristic transformation temperatures can be controlled by the variations in the aluminum and manganese content. Additionally, the effect of magnesium and iron on the transformation temperatures and thermodynamic parameters was investigated in the Cu-Al-Mn ternary system. The addition of the magnesium decreases the characteristic transformation temperatures of the Cu-Al-Mn system, but that of the iron increases. The structural changes of the samples were studied by X-ray diffraction measurements and optical microscope observations. Due to the low solubility of the magnesium, the magnesium addition into the Cu-Al-Mn system forms precipitates in the matrix. It is evaluated that the transformation parameters of the CuAlMn shape memory alloys can be controlled by the change of the alloying elements and the weight percentages of alloying elements.
10.1007-s00339-013-8179-0	2	corrosion; surface; film; electrochemical; films; spectroscopy; layer; current; solution; potential; resistance; composition; x-ray; ions; showed	This study focusses on the development and application of an innovative protocol which combines chemical data, GIS (geographical information system) and PCA, involving numeric (chemical composition) and categorical (typology of object, archaeological context, chronology and geographical areas) variables, as a simple tool to help in the visualisation and interpretation of large multidisciplinary datasets on Cu-based alloy archaeological artefacts influenced by Phoenician-Punic contacts. The protocol is a useful tool for highlighting existing connections between specific alloy chemical compositions, the location of the original settlement where the artefact had been produced and the proximity to mining resources, waterways, and allochthonous presence such as, in the specific case of this study, the Phoenician and Punic influence in the Iberian bronze production during the Late Bronze Age-Iron Age. The protocol was tested successfully in a case study concerning the precise dating and provenance of bronze statuettes of unknown age and provenance from the Evora Museum collection in Southern Portugal where it confirmed and further refined earlier hypotheses based solely on archaeological and/or chemical studies. The results were interpreted with a unique perspective, to validate the GIS system in combination with experimental chemical-physical data to yield the identification of metallurgical sites of bronze production.
10.1007-s00339-014-8342-2	2	corrosion; surface; film; electrochemical; films; spectroscopy; layer; current; solution; potential; resistance; composition; x-ray; ions; showed	This work presents the application of voltammetry of microparticles (VMP) to the characterization of metallic artefacts. The paper illustrates the principle of the technique and the methods for the identification of metals and copper minerals. VMP can be considered a non-invasive technique as it requires a minimum amount of material for performing the analyses. To emphasize the efficacy of this technique regarding characterization of cultural heritage materials, two bronze artefacts of different historical periods were investigated. By using a paraffin-impregnated graphite electrode, the composition of the alloy and the copper minerals present in their patinas were analysed and identified. The results obtained from the electrochemical characterization were confirmed by complementary analysis carried out with X-ray fluorescence and X-ray diffraction.
10.1007-s00339-014-8383-6	4	transformation; martensite; martensitic; phase; shape; beta; memory; shape memory; temperature; temperatures; martensitic transformation; gamma; transformation temperatures; effect; thermal	In this study, the Cu-Al-Mn-X (X = Ni, Ti) shape memory alloys at the range of 10-12 at% of aluminum and 4-5 at% manganese were produced by arc melting. We have investigated the effects of the alloying elements on the transformation temperatures, and the structural and the magnetic properties of the quaternary Cu-Al-Mn-X (X = Ni, Ti) shape memory alloys. The evolution of the transformation temperatures was studied by differential scanning calorimetry with different heating and cooling rates. The characteristic transformation temperatures and the thermodynamic parameters were highly sensitive to variations in the aluminum and manganese content, and it was observed that the nickel addition into the Cu-Al-Mn system decreased the transformation temperature although Ti addition caused an increase in the transformation temperatures. The effect of the nickel and the titanium on the thermodynamic parameters such as enthalpy and entropy values was investigated. The structural changes of the samples were studied by X-ray diffraction measurements and by optical microscope observations at room temperature. It is evaluated that the element Ni has been completely soluble in the matrix, and the main phase of the Cu-Al-Mn-Ni sample is martensite, and due to the low solubility of the Ti, the Cu-Al-Mn-Ti sample has precipitates, and a martensite phase at room temperature. The magnetic properties of the Cu-Al-Mn, Cu-Al-Mn-Ni and Cu-Al-Mn-Ti samples were investigated, and the effect of the nickel and the titanium on the magnetic properties was studied.
10.1007-s00339-014-8394-3	4	transformation; martensite; martensitic; phase; shape; beta; memory; shape memory; temperature; temperatures; martensitic transformation; gamma; transformation temperatures; effect; thermal	In this study, isothermal oxidation behavior of a Cu-Al-Ni-Fe shape-memory alloy between 500 and 900 A degrees C was investigated. Alloy samples were exposed to oxygen by TG/DTA for 1 h at a constant temperature, allowing for calculation of the oxidation constant and activation energy values of the oxidation process. The oxidation constant value increased with temperature, reaching saturation at 800 A degrees C. The effect of oxidation on crystal structure, surface morphology and chemical composition of the Cu-Al-Ni-Fe alloy was determined by X-ray diffractometer (XRD) and scanning electron microscope (SEM)-energy-dispersive X-ray (EDX) analyses. With increasing oxidation temperature, number and intensity of the characteristic 18R martensite phase peaks were reduced while Al2O3 phase peaks were increased. In parallel to the XRD results, the same variations were also detected by SEM-EDX measurements.
10.1007-s00339-014-8643-5	4	transformation; martensite; martensitic; phase; shape; beta; memory; shape memory; temperature; temperatures; martensitic transformation; gamma; transformation temperatures; effect; thermal	There are many studies to improve the properties of Cu-Al-Mn shape memory alloys, such as high transformation temperatures, ductility and workability. Most of them have been performed by adding a quaternary component to the alloy. In this study, the effect of trace Mg addition on transformation temperatures and microstructures of three different quaternary Cu-Al-Mn-Mg alloys has been investigated using thermal analysis, optical microscopy and XRD techniques. The transformation temperatures are within the range of 120-180 degrees C, and they have not changed significantly on decreasing the Mn content, replacing with Mg. The fine precipitates have been observed in the alloys with the Mg content up to 1.64 at%. Calculated entropy change and XRD analysis reveal that the alloys with high Al content have mainly 18R-type structure which could be responsible for good ductility and workability.
10.1007-s00339-014-8759-7	-1		This research experimentally analyzed the influence of the open area ratio (OAR) on the formation and growth of the microstructure in Cu-Ni alloy electrodeposition. The OAR was controlled by changing the pitch of circular patterns with a diameter of 20 A mu m. For an OAR higher than 20 %, the electrodeposited structures grew vertically in pillar-like formations. As the OAR was decreased from 100 to 20 %, the density, height, and width of the structures increased. In addition, in this OAR range, the structures formed along the edge area of the circular patterns. In contrast, for an OAR lower than 10 %, dendrite structures were generated. The electrodeposited structures were coated with a hydrophobic plasma-polymerized fluorocarbon (PPFC) layer. In the electrodeposited sample without circular patterns (OAR = 100 %) with an OAR smaller than 1.25 %, the measured contact angles were almost the same as the contact angle (107A degrees) measured from the flat surface without electrodeposition. In contrast, the samples with an OAR range of 2.5-50 % were modified to be superhydrophobic, and they demonstrated an excellent self-cleaning ability.
10.1007-s00339-015-9271-4	4	transformation; martensite; martensitic; phase; shape; beta; memory; shape memory; temperature; temperatures; martensitic transformation; gamma; transformation temperatures; effect; thermal	The work functions of Cu-2.7Be and Cu-2.0Be (wt%) alloys were measured using ultraviolet photoelectron spectroscopy, and their dependence on secondary phase characteristics (composition and distribution) was investigated. The work function properties were significantly altered when the Be content was increased from 2.0 to 2.7 wt%, which was attributed to the introduction of secondary phases (beta and gamma) in the alloys with higher Be content. Furthermore, the distribution of secondary phases may also have influenced the gradients of the work function curves measured by UPS.
10.1007-s00339-016-0079-7	4	transformation; martensite; martensitic; phase; shape; beta; memory; shape memory; temperature; temperatures; martensitic transformation; gamma; transformation temperatures; effect; thermal	This paper is aimed at studying influence of various heat treatments on transformation temperatures and electrical resistance properties of alloys from binary Cu-Mn system. It was noticed that with an increase in sample's grain size, transformation temperatures also increased. The activation energies of samples were calculated according to Kissinger and Augis-Bennett. Thermogravimetric and differential thermal analysis measurements were used to investigate phase transformations and kinetic parameters. The electrical values of resistance of alloy were investigated at different temperatures. The resistance as a function of quenching temperature showed a decrease. Depending on quenching techniques, Cu-Mn alloy can display different product phases such as parent phase and precipitation.
10.1007-s00339-016-0222-5	1	shape; memory; shape memory; damping; martensite; martensitic; damping capacity; transformation; capacity; strain; superelasticity; temperature; cu-al-mn; shape memory effect; effect	The effects of B addition on the magnetization, mechanical and shape memory properties in Cu70-xAl24-Mn6Bx at% (x = 0, 1, 2, 3, 4) alloys have been investigated. The ductility was decreased, while the strength was improved with B addition. Transformation temperatures were increased with B content due to increased e/a ratio. Martensite start temperature of B-free CuAlMn was found to be 37.3 degrees C and increased to 218.8 degrees C with 4 % B addition. B-free CuAlMn exhibited shape memory effect with a recoverable strain of 2.25 % under 200 MPa and a perfect superelasticity with a recoverable strain of 2.5 % at 163 degrees C. B addition degraded the shape memory properties and eventually resulted in the lack of recoverable strain. In addition, saturation magnetization was increased with B content. Moreover, the addition of B slightly decreased the ductility of the alloy. It was found that the magnetization, mechanical and shape memory properties CuAlMn alloys can be tailored by quaternary alloying with B.
10.1007-s00339-016-0354-7	2	corrosion; surface; film; electrochemical; films; spectroscopy; layer; current; solution; potential; resistance; composition; x-ray; ions; showed	A collection of 35 metallic artefacts comprising various typologies, some of which can be attributed to the Bronze Age and others to later periods, were studied to provide detailed information on elemental composition, manufacturing techniques and preservation state. Elemental analysis by micro-EDXRF and SEM-EDS was performed to investigate the use of different alloys and to study the presence of microstructural heterogeneities, as inclusions. X-ray radiography, optical microscopy and SEM-EDS were used to investigate manufacturing techniques and degradation features. Results showed that most of the artefacts were produced in a binary bronze alloy (Cu-Sn) with 10-15 wt% Sn and a low concentration of impurities. Other artefacts were produced in copper or in brass, the latest with varying contents of Zn, Sn and Pb. A variety of inclusions in the metal matrices were also found, some related to specific types of alloys, as (Cu-Ni)S-2 in coppers, or ZnS in brasses. Microstructural observations revealed that the majority of the artefacts were subjected to cycles of thermomechanical processing after casting, being evident that among some artefacts different parts were subjected to distinct treatments. The radiographic images revealed structural heterogeneities related to local corrosion processes and fissures that seem to have developed in wear-tension zones, as in the handle of some daggers. Radiographic images were also useful to detect the use of different materials in one particular brass artefact, revealing the presence of a possible Cu-Sn solder.
10.1007-s00339-016-0420-1	-1		Cu2CdSnS4 quaternary alloy nanostructures with different copper concentrations (0.2, 0.4, 0.6, 0.8 and 1.0 M) were successfully synthesized on n-type silicon substrates using spin coating technique with annealing temperature at 300 degrees C. Optical properties were analyzed through UV-Vis and Photoluminescence spectroscopies, and thus, there is a change in energy band gap with increasing Cu concentration from 0.2 to 1.0 M. The structural properties of Cu2CdSnS4 quaternary alloy nanostructures were investigated by X-ray diffraction. The particles size and shape have a direct relationship with copper concentration. Morphological and topographical studies were carried out by using scanning electron microscopy and atomic force microscopy. The obtained results are investigated to be available in the literature for future studies.
10.1007-s00339-016-0505-x	0	solidification; phase; magnetic; magnetic field; undercooling; field; liquid; separation; peritectic; immiscible; cu-; dendrite; phase separation; microstructure; primary	The active control of microstructure evoluztion is still a challenging factor for the development of advanced immiscible alloys. Here, we make an attempt to modulate the solidification pathways of undercooled Cu62.5Fe27.5Sn10 alloy by glass fluxing and drop tube techniques. Through regulating the liquid undercooling, three types of microstructures, dendrite, dispersive structure and macrosegregation pattern, were formed under the normal gravity condition. Below the first critical undercooling of 15 K, the alloy melt displayed the normal peritectic solidification. At moderate undercoolings above 15 K, the metastable liquid phase separation took place and the solidified microstructure appeared as homogeneously dispersed structure. If undercooling further overtook the second threshold of 107 K, macrosegregation occurred and the bulk alloy separated into an Fe-rich zone and a Cu-rich zone. Under the free fall condition, the alloy droplets with the droplet diameter beyond 805 mu m showed the equilibrium peritectic solidification. If the droplet diameter decreased below 805 mu m, the metastable liquid phase separation was induced and the microstructural morphology of Cu62.5Fe27.5Sn10 alloy droplet evolved from dendrite into dispersive structure. Furthermore, experimental and simulated results revealed that the temperature gradient had great influence on the size distribution of Fe-rich globules.
10.1007-s00339-016-0608-4	-1		The conventional approach to studying laser-workpiece interaction in the ablation regime is to vary beam parameters used on a specimen of uniform chemical composition. The current work instead utilises a pulsed laser beam of constant parameters to ablate a ternary alloy thin film where the chemical composition of the sample varies continuously; this will enhance the understanding of pulsed laser ablation by means of a combinatorial approach . The analysis of the studied workpiece (a Cu-AlNi thin film deposited by magnetron sputtering) revealed the presence of both compositional and morphological gradients. Variation in the surface morphology was correlated with aluminium content. Single-pulse laser ablation (Nd:YAG, 1064 nm, 30 ns, 4.54 J/cm(2)) of the surface resulted in different crater features, geometry and volume. Two characteristic regions separated by a transition zone were identified based on the craters' geometrical and morphological characteristics. The ablated volume increases with the atomic percentage of aluminium up to a threshold value of roughly 30 at% after which the ablation volume slowly declines. This phenomenon may be attributed to plasma absorption and heat dissipation in the thin film.
10.1007-s00339-018-2057-8	11	glass; bulk; metallic; bulk metallic; gfa; bmg; glassy; metallic glass; ability; bulk metallic glass; amorphous; addition; crystallization; mm; glass-forming	In this paper, glass-forming ability, viscosity, fragility and microhardness of three Cu-based bulk metallic glasses are evaluated by differential scanning calorimetry, thermomechanical analysis and hardness testing. The results suggest that Y element can effectively affect the packing state and properties of Cu-based bulk metallic glasses. The variation of glass-forming ability, viscosity, fragility index and hardness indicates that alloying with low quantity of additions can remarkably change the characteristic temperatures during glass transition stage but cannot cause an apparent modification in the solidification/melting stage.
10.1007-s00339-020-03475-9	1	shape; memory; shape memory; damping; martensite; martensitic; damping capacity; transformation; capacity; strain; superelasticity; temperature; cu-al-mn; shape memory effect; effect	This study presents the effect of Ta addition on martensitic transformation behavior and shape memory properties of Cu82.6-xAl12.4Ni4Mn1Tax (x = 0, 1, 2 and 3 wt%) high-temperature shape memory alloys. The results indicated that martensite structure, phase components, transformation characteristics and shape recovery ratios of the Cu82.6-xAl12.4Ni4Mn1Tax alloys remarkably changed with the addition of Ta element. The alloys display dual-phase martensite structure (beta 1 '+gamma 1 ') for x = 0 and 1, whereas those for x = 2 and 3 have only the beta 1 ' martensite phase. It is seen that the shape memory properties of the alloys improve considerably as a result of the addition of Ta and the highest shape recovery ratio of 87.5% is achieved with 3 wt% Ta-added alloy.
10.1007-s00339-020-03604-4	4	transformation; martensite; martensitic; phase; shape; beta; memory; shape memory; temperature; temperatures; martensitic transformation; gamma; transformation temperatures; effect; thermal	The effect of aging on the properties of a Cu-12.4Al-1.2Ti-1.2Ta (wt%) high-temperature SMA was investigated throughout SEM/EDS, XRD and DSC experiments. It was found that the transformation behavior, the thermal properties and the phase structure of the alloy remarkably changed with homogenization process performed at 900 degrees C for 20 min and then aging at 400 and 500 degrees C for 1 h . Structural and morphological investigations revealed that the homogenization process caused martensitic decomposition in the alloy and austenite phase domains remained. Afterward, with the effect of thermal aging, the amount of the austenite phase increased and the alpha-phase domains nucleated and grew in the alloy. At elevated aging temperature, the amounts of the austenite and the alpha-phases in the alloy considerably increased and martensitic morphology disappeared. As a result of these, the phase structure of the alloy affected its thermal behavior and led to exhibit irreversible one-stage martensitic transformation behavior.
10.1007-s00339-020-03886-8	16	wear; composite; composites; powders; milling; particles; powder; wt; sliding; friction; hardness; matrix; mechanical; surface; properties	In this study, the microstructural, physical and mechanical properties of the nanocrystalline Cu-Ta material synthesized by mechanical milling and subsequent sintering were investigated affected by Ta content and sintering temperature. Scanning electron microscope and X-ray diffraction results showed that increasing Ta content from 1 to 5 wt% changed the material behavior during milling and resulted in reduction of powder particle size and crystallite size. For the sintered specimens, addition of Ta decreased the electrical conductivity due to reduced density and increased electron scattering effect while micro-hardness of Cu matrix was promoted. The higher sintering temperature about 850 degrees C also increased density and provided more segregation of Ta which was led to improvement in both micro-hardness and electrical conductivity of Cu-Ta composite. In addition, a comparison between sintering process at 850 degrees C by SPS method and conventional cold pressing- sintering revealed that SPS has a high potential to enhance physical and mechanical properties.
10.1007-s00339-020-3412-0	16	wear; composite; composites; powders; milling; particles; powder; wt; sliding; friction; hardness; matrix; mechanical; surface; properties	Copper (Cu)-based nanocomposites were produced by mechanical alloying process using various volume percentages of graphene up to 8 vol.%. Subsequently, nanocomposites powders were milled for 20 h, cold-pressed and subjected to different sintering temperatures up to 850 degrees C for 1 h in argon atmosphere. Furthermore, X-ray diffraction technique along with transmission electron microscopy (TEM) was employed to examine the milled powders. The microstructure, physical, mechanical, electrical properties and wear behavior of the sintered nanocomposites samples were determined also. The obtained TEM micrographs showed homogenous distribution of graphene in Cu matrix and noticed grains refinement. Additionally, it was responsible for measurable decreases in the densification and the electrical conductivity of the sintered bodies. Furthermore, the mechanical properties, on the contrary to work-hardening capacity, of the sintered samples were improved by the increasing in graphene contents and sintering temperatures. The weight loss and wear rate of nanocomposites reduced with both of graphene content and sintering temperature, while increased with increasing in the applied load. Taking all these results into consideration, we can conclude that Cu-graphene nanocomposites are promising candidates for industrial applications.
10.1007-s00339-023-06696-w	4	transformation; martensite; martensitic; phase; shape; beta; memory; shape memory; temperature; temperatures; martensitic transformation; gamma; transformation temperatures; effect; thermal	This work presents effects of heat treatments at 300 degrees C, 400 degrees C and 500 degrees C for 1 h on structural/microstructural properties, transformation temperatures and some thermodynamic parameters of a Cu-12.4Al-2.5Fe-1Zr (wt%) HTSMA via XRD, SEM/EDX and DSC. Microstructure of the alloy contains 18R and 2H martensite phases, Cu9Al4 precipitates and voids. The results reveal that orientations of the 18R martensite, degree of long-range order, fractions of the Cu9Al4 precipitates, transformation temperatures and energies required for martensite nucleation and stored during martensitic transformation of the alloy change depending on the heat treatment temperature. As the heat treatment temperature raises up to 500 degrees C, both there have been shifts in the transformation temperatures of the alloy and energies required for transformations altered. Therefore, it is observed that the transformation hysteresis of the alloy increased to 111.95 degrees C and whereas the elastic energy stored during cooling decreases, the driving force required for the nucleation of the martensite phase at M-s increases.
10.1007-s00339-023-06913-6	-1		The nano-dimple fracture complexions assessed from the published tensile fracture surfaces are perceived to predict the trend of variation in deformation and fracture properties of a supersaturated nanocrystalline face-centered cubic Cu-Co alloy with systematic isothermal annealing treatment. The alteration of different microstructural disposition that led to change in fracture complexions have been quantified, compared and interpreted with the respective mechanical properties of the alloy.
10.1007-s00339-024-07997-4	-1		This study investigated the dependence of irradiation fluence and pulse duration on the non-thermal alloying of Cu and Sn through laser irradiation. Femtosecond and picosecond laser irradiation were applied to the GaN part of a bilayer of Cu and Sn deposited on GaN. The laser beam operated at a wavelength and repetition rate of 1030 nm and 1 MHz, respectively, with pulse durations of 0.65 and 38 ps. Subsequently, the irradiated samples were thinned using a focused ion beam, and the cross-sections were examined with transmission electron microscopy. The lattice constants of the resultant phases were identified from selected area diffraction patterns. In data analysis, we identified the phases as beta-Sn and epsilon-phases first, if discernible within a 5% error margin, employing high-temperature phases when identification was not possible. In the irradiated area, only Cu and Sn were detected under a lower fluence and shorter pulse duration. However, delta-phases, which are alloys of Cu and Sn, formed at relatively higher fluences and longer pulse durations. This high-temperature phase, unique to picosecond laser irradiation, cannot be obtained through conventional thermodynamic processes, highlighting the unique capabilities of laser-induced processing in creating novel alloy phases. These findings advance our understanding of laser-material interactions and provides a foundation for developing advanced materials with tailored properties for various applications.
10.1007-s00339-025-08973-2	-1		Three-dimensional (3D) orthogonal ultrasounds were introduced into ternary Cu-33%Sn-15%Bi immiscible alloy to control its liquid-phase separation. Compared to the layered structure formed under static condition, homogeneous dispersion of Bi-rich particles within the Cu3Sn matrix was facilitated by employing short-time ultrasounds during the final stage of liquid-phase separation. Conversely, long-time ultrasounds application throughout liquid-phase separation generated limited macro-segregation suppression effect. Numerical simulations indicated that although long-time ultrasounds enhanced droplet nucleation, it also induced significant acoustic shielding from cavitation bubbles, causing severe attenuation of acoustic energy and consequent reduction in droplet fragmentation and migration. This phenomenon weakened the fragmentation and the migration of Bi droplets. The homogeneous and refined microstructure produced by short-time 3D ultrasounds possessed superior electrochemical corrosion and wear-resisting properties. This work demonstrates that employing an appropriate ultrasonic processing time can inhibit cavitation-induced acoustic shielding and maximize energy utilization efficiency.
10.1007-s00419-021-02040-x	-1		High-performance alloy materials are increasingly considered for various engineering applications due to their combination of desirable properties. However, the guided wave-based structural health monitoring of alloys is often challenged by their strong anisotropic nature, which makes it difficult to calculate the guided wave behavior and associate mode shapes. In this article, Lamb mode waves of Cu-Al-Ni alloy under uniaxial stresses are characterized by developing a novel numerical polynomial approach, which may provide an efficient way to solve problems concerning acoustic wave propagations. To facilitate understanding of the dispersion curve trajectories, the anisotropic phase transformation from cubic phase (austenite) to orthorhombic plate (martensite) is considered. The comparison of the evanescent mode trajectories between the cubic and orthorhombic alloys shows the presence of imaginary modes in the cubic phase, although they may not exist in the orthorhombic phase at specific frequencies. In the case of Lamb propagation in the cubic alloy, the dispersion curves oscillate strongly, creating crossings among multiple symmetric and antisymmetric modes. This study also concerns the second harmonic generation of Lamb mode pairs in cubic and orthorhombic alloys. Furthermore, effect of uniaxial stresses on Lamb dispersion curves in both phases are also identified and discussed. The results obtained may promote understanding and optimization of novel acoustic devices made of anisotropic materials.
10.1007-s00604-003-0097-y	2	corrosion; surface; film; electrochemical; films; spectroscopy; layer; current; solution; potential; resistance; composition; x-ray; ions; showed	In many Italian archaeological sites dated between the sixth and third centuries BC, unworked lumps of Cu-based materials are sometimes found, the so called Aes Rude, which according to archaeological considerations were appreciated as currency, as a medium of exchange and as a form of saving. The microchemical investigation of these ancient artefacts discloses their nature as apparently not usable for any functional applications or possible use. Indeed, Aes Rude resemble ordinary copper material, but microchemical results indicate that they are constituted by highly ferruginous leaded copper, making them useless for producing other metal objects by means of casting or hot and cold working. Notwithstanding this intrinsic negative feature, the production of these intractable Cu-based alloys was deliberately carried out to maximise the process yield in terms of produced metal from an impure and unselected metal ore by tailoring the smelting process parameters. With these considerations in mind, the microchemical investigation of these ancient iron-copper alloys gives evidence of the passage from the acceptance of an artefact value based on its true nature or potential use to the acceptance of the value based only on its appearance or form irrespective of its present or future use. This information could contribute to a better understanding of the evolution of human thought and economic and social interactions.
10.1007-s006040070086	2	corrosion; surface; film; electrochemical; films; spectroscopy; layer; current; solution; potential; resistance; composition; x-ray; ions; showed	Patinas naturally formed on archaeological bronze alloys were characterized using light microscopy (LM), micro energy dispersive X-ray fluorescence analysis (mu-EDXRF), time of flight secondary ion mass spectrometry (TOF-SIMS) and scanning electron microscopy in combination with energy dispersive X-ray microanalysis (SEM/EDX). The examinations carried out on cross-sections of samples have shown that in all samples the copper content in the corrosion layer is lower than in the bulk, while an increase of tin and lead could be observed. Two different types of corrosion were found: first type, a corrosion formation leading to a three layer structure was observed on lead bronze. The outer layer consists mainly of Cu(II) compounds and soil material, followed by a fragmented layer of cuprous oxide and the surface layer of the alloy, where a depletion of copper and an enrichment of tin and high amounts of Cl could be detected, The second type of corrosion is characterized by a two layer structure on the tin bronze sample consisting of an outer layer with copper containing corrosion products and a layer with cracks, which reveals a depletion of copper whereas tin and lead are enriched. Also high amounts of Si were detected in this surface layer.
10.1007-s00707-022-03271-x	-1		Recent experimental studies have proved that by interface design and microstructural control of metals with the heterogeneous dual/multi-phases, one can significantly improve their mechanical properties such as fatigue resistance, strength, and plasticity. In this work, a mechanism and microstructure-based theoretical model is developed to describe the constitutive and failure behaviors of hierarchical dual-phased gradient Cu-Zr alloys. In the framework of micromechanical model, the constitutive relations of crystalline and amorphous phases are employed, and the contributions of gradient structure, dual-phase structure, back stress, and microcracks are taken into account. The theoretical results demonstrated that the proposed model can describe the constitutive behavior and mechanical properties of hierarchical dual-phased gradient Cu-Zr alloys very well, and that the simulations agree well with the experimental data. The present model is further applied to predict the mechanical properties of Cu-Zr alloys with various distributions of the grain sizes and volume fractions of microstructures. The findings of this work could be helpful to provide the theoretical basis for achieving synergy of high strength and high ductility in metallic materials by controlling the gradient distribution and dual-phases microstructures.
10.1007-s00894-020-04440-2	-1		Cu-Ni binary alloy has become the attention of scientific world for its potentials in nanodevices. It is indispensable to investigate on the mechanical properties of this material due to lack of previous work done regarding this binary alloy. Molecular dynamics (MD) studies were performed on nanopillar (NP) structures comprised of Cu-Ni binary alloy having an FCC unit cell with Cu atoms selectively replaced by Ni atoms. This selective replacement resulted in a better stress behavior than the randomly replaced alloy structure when both tension and compression load were applied. The effect of crystal orientation, NP dimensions, temperature, and strain rate on the stress-strain curve of Cu-Ni binary alloy NPs was thoroughly investigated under tensile loading. This investigation reveals significant influence of crystal orientation on ultimate strength and flow stress region. Among four different crystal orientations, orientation shows maximum strength behavior under tensile loading, while shows highest strength under compressive load. However, in both cases, i.e. tension and compression, the poorest stress behavior was observed for orientation. Under tensile load, -oriented binary alloy fails due to the formation of Shockley partials followed by formation of complex dislocation network. On the other hand, -oriented binary alloy fails due to the formation of Lomer-Cottrell (LC) lock from the Shockley partials. Total dislocation length is calculated, and its effect on the stress-strain behavior of the Cu-Ni binary alloy is discussed. Highest Young's modulus and yield stress are observed on -oriented binary alloy among other orientations, and these values for -oriented NP was found to decrease with the increment of temperature. If the temperature is increased, yield stress and Young's modulus decrease. The effect of cross section width was also investigated in this study, and it was found that yield stress decreases with the increment of cross section width due to the effect of surface atom fraction. Increasing the strain rate causes the initiation of amorphous structure, resulting in superplastic behavior of the -oriented Cu-Ni binary alloy NP.
10.1007-s00894-021-04886-y	-1		In the present work, investigation of structural evolution of Cu33Zr67 specimen during the cooling process from 2500 down to the 300 K, 200 K, 150 K, 100 K, 50 K, and 10 K has been performed at cooling rate of 5 K/ps using molecular dynamics simulation. The pair distribution function (PDF) reveals that Zr-Zr pair causes the splitting of the first peak of the Cu33Zr67 glass at a lower temperature with an increase in height. Splitting of the first and second peaks supports the presence of the inhomogeneous structure with a statistical average of crystal-like and disordered structural regions in the Cu33Zr67 glass. Voronoi cluster analysis indicated that quasi icosahedral clusters such as < 284 > , < 0285 > , and < 0282 > ; mixed-type cluster such as < 0364 > ; and crystal-like clusters such as < 0446 > are responsible for stabilization of glassy phase at 300 K, 200 K, 150 K, 100 K, 50 K, and 10 K. Similarly, the maximum population of the Cu-centered and Zr-centered < 0286 > quasi icosahedral clusters support the stability of the glassy phase over the studied temperature range. Besides, the maximum population of Cu-centered < 0367 > and Zr-centered < 0364 > , < 0367 > , < 0363 > , and < 0365 > mixed-type clusters and Cu-centered < 0448 > and Zr-centered < 0448 > , < 0445 > , < 0446 > , and < 0444 > crystal-like clusters support the possibility of the presence of intermediate phase of CuZr2 at lower temperatures as observed from PDFs. Mean square displacement (MSD) for the Cu33Zr67 glass shows that the diffusion coefficient of Cu and Zr atoms reduces with decreasing temperature from 300 to 10 K. Diversity parameter (d) was found to decrease with decreasing temperature.
10.1007-s00894-022-05183-y	-1		Temperature, strain rate, and defects are important considerations in determining the mechanical properties of materials. The mechanical properties of nanocrystalline copper-tantalum (Cu-Ta) alloy are investigated using classical molecular dynamics simulation approach in which embedded atom method of potential with periodic boundary conditions in all directions has been adopted. Numerical simulation has been performed to predict the mechanical properties of nanocrystalline copper-tantalum alloy. The virtual tensile test has been conducted at a fixed strain rate and increasing temperature where the discreet change in temperature from 50 to 1600 K has been used as a controlling parameter. The strain rate is fixed in the direction of the principal crystallographic planes and has not been affected by the change in temperature. The mechanical properties of the Cu-Ta nanocrystalline alloy such as yield strength, ultimate strength, and Young's modulus are observed. Further, simulations are carried out to analyze the vacancy formation energy with vacancy concentration and potential energy response at discrete temperatures. Nanocrystalline Cu-Ta alloy is observed to be more susceptible to failure at high temperatures. Particularly at 300 K, the strength of nanocrystalline Cu-Ta is 6 GPa which decreases to 4 GPa at 1200 K.
10.1007-s00894-022-05324-3	-1		The compositional dependence of the atomic structure and glass-forming ability (GFA) was systematically studied in a binary alloy series Cu100-xZrx (x = 0.5, 1.0, 2.0, 3.0, 5.0, 7.0, 10.0) by molecular dynamics simulations. Several structural analysis techniques are adopted to find a direct relationship between the atomic structures and GFA by minor Zr addition. The simulation results confirm that the difference among the critical cooling rates proves the enhancement of GFA. It is found that the Zr addition can enhance the icosahedra short-range order (SRO). From another side, in terms of MRO, the addition of Zr can enhance interpenetrating icosahedra connection which will give rise to the Bergman-icosahedra medium-range order, resulting in a more stable, more compact, and more complex structures, which is responsible for the enhanced GFA in CuZr alloys. Furthermore, the five-fold symmetry governs the formation of the amorphous state and may behave as a principal indication of the formation of the glass state during the cooling process. We also found a critical Zr content of 3%, below which the effect of Zr on the structures is not obvious. However, when the Zr content is higher than 3%, the Zr can rapidly change the structures of the liquid and glassy structure. These results are helpful for understanding the GFA of CuZr alloys.
10.1007-s10008-014-2522-z	2	corrosion; surface; film; electrochemical; films; spectroscopy; layer; current; solution; potential; resistance; composition; x-ray; ions; showed	The anodic formation of Cu(I) and Cu(II) oxides on polycrystalline copper and copper-gold alloys (4 and 15 at% Au) in deoxygenated 0.1 M KOH was examined by voltammetry, chronoamperometry, and chronopotentiometry with a synchronous registration of photocurrent and photopotential, in situ spectroscopy of photocurrent as well as XPS and SEM measurements. The band gap of p-Cu2O is 2.2 eV for indirect optical transitions independent of the concentration of gold in Cu-Au alloy. It grows on CuOH or n-Cu2O underlayer. The increase of anodic potential results in a thickening of oxide film which is a mixture of Cu(I) and Cu(II) oxides. The latter is a p-type semiconductor with a low photosensitivity. The rate of oxide formation on the alloys is lower than on copper. The structure-dependent properties of the oxide phase on the alloys and copper are different. Copper is prone to corrosive oxidation even in deoxygenated alkaline solution by the traces of molecular oxygen. The corrosive growth of Cu(I) oxide film occurs according to the parabolic law. After the cathodic polarization, the surface of copper remains free of corrosive oxide no longer than 15-20 min. The preliminary anodic formation even of a thin Cu2O film as well as the alloying of copper with gold suppresses the corrosive oxidation of copper.
10.1007-s10008-016-3339-8	2	corrosion; surface; film; electrochemical; films; spectroscopy; layer; current; solution; potential; resistance; composition; x-ray; ions; showed	With the help of the factorial design of experiments, optimization of the deposition of the CuW alloy was successfully done. The important deposition parameters were identified as pH, current density, and-the most important one-copper ion concentration. All of them were examined in their wide ranges. Under optimal conditions, in a citrate bath, with copper ion concentration of 1.0 mM, at current density of -100 mA cm(-2) and at pH ca. 8.3, the alloy layer had the highest tungsten content (circa 30 wt%), satisfactory adhesion and a smooth and crackless morphology. The structure of the electrodeposited alloy can be described as an amorphous solid solution of Cu in W with built-in Cu nanocrystals.
10.1007-s10008-021-04914-0	2	corrosion; surface; film; electrochemical; films; spectroscopy; layer; current; solution; potential; resistance; composition; x-ray; ions; showed	The requirements for using noncyanide imitation gold plating as decorative electroplating are increasing; thus, continuously improving the quality of the coating of the imitation gold plating and optimizing the coating process have become the current priority. In this experiment, hydroxyethylidene diphosphonic acid (HEDP) was used as the main complexing agent; CuSO4 center dot 5H(2)O, ZnSO4 center dot 7H(2)O, and NaSnO3 center dot 3H(2)O were the main salts; and NaOH and sodium carbonate were used as the buffers to prepare the electroplating solution. Using sodium citrate (SC), sodium potassium tartrate (SS), sodium gluconate (SG), and glycerol (Gl) as four additives, the effects of the number of carboxyl groups on the properties of a Cu-Zn-Sn alloy coating were compared. The electrochemical analysis showed that Cu-Zn-Sn alloy codeposition occurred at -0.50 V-vs.Hg|HgO. The scanning electron microscopy (SEM) results showed that the grain size of the coatings obtained with carboxyl-containing additives was more uniform than that obtained with the electroplating solution without additives. The X-ray fluorescence spectrometry (XRF) analysis revealed that the composition of the Cu-Zn-Sn alloy coating obtained by using SC as an additive in the electroplating solution was 89.75 wt% Cu, 9.61 wt% Zn, and 0.64 wt% Sn, and the color of the coating was golden yellow. The X-ray diffraction (XRD) pattern showed that the coating was a mixture of Cu, Cu5Zn8, CuSn, Cu6Sn5, and CuZn phases. The analysis of the electroplating solution by UV, IR, and NMR spectroscopy methods indicates that the additives improve the coating by affecting the complexation reaction of metal ions. These results can provide technical guidance for developing Cu-Zn-Sn ternary alloy electrodeposition technology with the new cyanide-free HEDP alkaline electroplating system.
10.1007-s10008-021-05086-7	2	corrosion; surface; film; electrochemical; films; spectroscopy; layer; current; solution; potential; resistance; composition; x-ray; ions; showed	The paper presents several experimental results regarding the electrodeposition of Cu-Sn alloy coatings prepared in ChCl-EG deep eutectic solvents (DESs). The electrochemical behavior of Cu2+ and Sn2+ on glassy carbon electrode (GC) was studied by cyclic voltammetry (CV). The nucleation mechanism of Cu2+ and Sn2+ at different potentials was analyzed by the potentiostatic current density transient (chronoamperometry (CA)). Surface and phase composition of Cu-Sn alloy coating were characterized by scanning electron microscopy (SEM/DEX) and X-ray diffraction (XRD). The corrosion resistance of Cu-Sn coating was studied by potentiodynamic polarization (Tafel) and electrochemical impedance spectroscopy (EIS). From the results, it can be seen that the Cu-Sn alloy can be co-deposited at the potential from-0.5 to-0.8 V. The surface of the coating showed a different microstructure when the deposition potential changed. With the negative shift of deposition potential (- 0.5 to-0.8 V), the particle size of the coating decreased. Comparison in the corrosion behavior of the coatings showed that the change of Sn content had an effect on the corrosion resistance of Cu-Sn alloy. The thickness of the coating (from 7 to 11 mu m) was obtained by electrodeposition at-0.8 V (1 h).
10.1007-s10338-008-0801-x	1	shape; memory; shape memory; damping; martensite; martensitic; damping capacity; transformation; capacity; strain; superelasticity; temperature; cu-al-mn; shape memory effect; effect	The mechanical behavior of shape memory alloys (SMAs) is closely related to the formation and evolution of its microstructures. Through theoretical analysis and experimental observations, it was found that the stress-induced martensitic transformation process of single crystal Cu-based SMA under uniaxial tension condition consisted of three periods: nucleation, mixed nucleation and growth, and merging due to growth . During the nucleation, the stress dropped rapidly and the number of interfaces increased very fast while the phase fraction increased slowly. In the second period, both the stress and the interface number changed slightly but the phase fraction increased dramatically. Finally, the stress and the phase fraction changed slowly while the number of interfaces decreased quickly. Moreover, it was found that the transformation could be of multi-stage: sharp stress drops at several strains and correspondingly, the nucleation and growth process occurred quasi-independently in several parts of the sample.
10.1007-s10409-012-0140-5	6	grain; deformation; strain; strength; dislocation; cu-; tensile; size; ecap; grain size; sfe; ductility; hardening; high; stress	Molecular dynamics simulations of nanocrystalline Cu with average grain sizes of 3.1 nm, 6.2 nm, 12.4 nm and 18.6 nm under uniaxial strain and stress tension at strain rates of 10(8) s(-1), 10(9) s(-1) and 10(10) s(-1) are performed to study the combined grain size, strain rate and loading condition effects on mechanical properties. It is found that the strength of nanocrystalline Cu increases as grain size increases regardless of loading condition. Both the strength and ductility of nanocrystalline Cu increase with strain rate except that there is no monotonic relation between the strength and strain rate for specimens under uniaxial strain loading. Moreover, the strength and ductility of specimens under uniaxial strain loading are lower than those under uniaxial stress loading. The nucleation of voids at grain boundaries and their subsequent growth characterize the failure of specimens under uniaxial strain loading, while grain boundary sliding and necking dominate the failure of specimens under uniaxial stress loading. The rate dependent strength is mainly caused by the dynamic wave effect that limits dislocation motion, while combined twinning and slipping mechanism makes the material more ductile at higher strain rates.
10.1007-s10765-004-5757-6	-1		Experimental data for the surface tension, density, and electrical resistivity of undercooled liquid Cu-Ni alloys of different compositions and at different temperatures are presented. The experiments were performed in facilities that combine the containerless positioning method of electromagnetic levitation with contactless measurement techniques. Although Cu-Ni alloys are rather simple from a chemical point of view, the data for density, surface tension, and electrical resistivity unveil the occurrence of short-range atomic order processes in the melt. For the density this manifests in a composition-dependent excess volume, for the surface tension in smaller values due to an increased surface segregation, and for the electrical resistivity in a deviation from the linear temperature dependence at low temperatures.
10.1007-s10765-007-0209-8	12	thermodynamic; ternary; phase; data; experimental; equilibria; phase equilibria; liquid; binary; experimental data; calculated; phases; literature; model; calphad	The density and surface tension of Cu-Co-Fe alloys have been measured using the non-contact technique of electromagnetic levitation. At temperatures above and below the liquidus point, the density and surface tension are linear functions of temperature. The experimental density results can be predicted by means of the regular solution model from the binary phases alone, i.e., no assumption about ternary interactions needs to be made. The surface tension values are in good agreement with numerical solutions of the Butler equation if the known Gibbs excess energies are used. It is found that, for Cu-Co-Fe, it is possible to predict the surface tension from the binary systems as well. In addition to this, the surface tension is insensitive to substitution of the two transition metals, Co and Fe.
10.1007-s10765-007-0245-4	-1		Liquid state densities and electrical resistivities of pure copper and nickel as well as some of their binary alloys in the vicinity of the constantan mixing ratio (Cu53Ni47 at%) were measured by electromagnetic levitation and pulse-heating techniques. The experiments were performed as part of a joint project between the German Aerospace Center (DLR) and Graz University of Technology (TUG) with the main objective being to compare and support deeper understanding of different techniques for electrical resistivity measurements and their data. The manufacture of a levitation experiment similar to the setup at DLR is underway, which is scheduled for microgravity (mu g) experiments onboard the ISS in 2010. As a first step, DLR performed measurements on a set of binary Cu-Ni-alloys (as well as two pure constituents), and independent experiments for constantan and the two pure metals were conducted at TUG. The results give promising agreement between the two techniques, show a reasonable overlap within the estimated uncertainties, and lead the way to more comparative measurements with newly developed materials.
10.1007-s10765-014-1660-y	-1		Accurate and precise measurements of the temperature are important for controlling conditions in any experimental design. In containerless processing, such as in electrostatic levitation and electromagnetic levitation, the temperature is typically measured using optical pyrometers. These are generally calibrated to the sample of interest by measuring the temperatures of phase transitions. The presence of multiple heat signatures, differences in emissivity for different phases, and inconsistencies in published phase diagrams can make this difficult. In this manuscript, a method for using differential scanning calorimetry measurements for calibration is outlined and applied to four Cu-Zr alloys from the eutectic to the line compound. This technique is particularly valuable for systems in which accurate phase diagram information is unavailable or inaccurate.
10.1007-s10765-014-1742-x	13	clusters; atomic; glass; atoms; composition; dynamics; metallic; icosahedral; glasses; simulations; molecular; cu-zr; molecular dynamics; metallic glasses; structural	A first-principles calculations have been performed based on density functional theory to study the thermal properties of copper. Calculations have been performed using the pseudo-potential method within the generalized gradient approximation (GGA) and local density approximation. Thermodynamic properties including the bulk modulus, thermal expansion coefficient, and heat capacities at constant volume and constant pressure were calculated as a function of pressure and temperature using three different models based on the quasi-harmonic approximation: the Debye-Slater model, the Debye-Gruneisen model, and the full quasi-harmonic model (that requires the phonon density of states at each calculated volume). Also, empirical energy corrections are applied to the results of the three models. The electronic contributions to the specific heat are calculated and discussed, and it was found that they become important at high temperatures. The calculated values are in good agreement with experimental results. It is found that the full quasi-harmonic model with the GGA approximation provides more accurate estimates in comparison with the other models.
10.1007-s10765-015-2023-z	-1		The surface tension of liquid Cu-5Sn (copper with 5wt% tin) in the temperature range from 1290 K to 1560 K was measured by an oscillating drop technique combined with electromagnetic levitation. The levitation device uses an inhomogeneous radiofrequency electromagnetic field inside a levitation coil to position and to heat metallic material. Eddy currents are induced in a specimen to heat it to the liquid phase and to exert a Lorentz force, pushing it against gravity towards regions of lower field strength . The levitating liquid specimen takes the shape of a sphere, which is rotating and oscillating. The oscillations are recorded by a high-speed camera at 600 fps; the temperature of the specimen is measured by a fast near-infrared pyrometer. A linear fit to the measured surface tension gamma of Cu-5Sn as a function of temperature T in Kelvin is given by: gamma(T)(mN . m(-1)) = 1195-0.052 . (T-1318).
10.1007-s10789-005-0242-6	12	thermodynamic; ternary; phase; data; experimental; equilibria; phase equilibria; liquid; binary; experimental data; calculated; phases; literature; model; calphad	The p-T phase diagram of the Cu-Te system is constructed using the T-x phase diagram reported earlier, the vapor compositions over the copper tellurides Cu2Te, Cu3-xTe2, and CuTe, and their dissociation pressures.
10.1007-s10789-005-0259-x	12	thermodynamic; ternary; phase; data; experimental; equilibria; phase equilibria; liquid; binary; experimental data; calculated; phases; literature; model; calphad	The reported standard functions of formation of copper tellurides are critically evaluated and optimized. The thermodynamic data obtained for hitherto unexplored phases shed some light on the origin of discrepancies between the T-x phase diagrams of the Cu-Te system reported by different groups.
10.1007-s10800-005-6726-x	2	corrosion; surface; film; electrochemical; films; spectroscopy; layer; current; solution; potential; resistance; composition; x-ray; ions; showed	The electrochemical behaviour of Cu-xZn alloys and of Cu and Zn metals was studied by cyclic voltammetry and chronopotentiometry in borate buffer, pH = 9.2, with and without the addition of chloride ions in the range from 0.01 M to 1 M. In general, the shape of voltammograms of four Cu-xZn alloys with 10-40 wt% of zinc resembles that of copper more than that of zinc. With increasing zinc content several characteristics of zinc are observed. In borate buffer containing chloride anions, Cu-xZn alloys are susceptible to pitting corrosion. The breakdown potential, E-b, at which the current density in the passive region starts to increase abruptly, becomes more negative with increasing zinc content in the alloy. The general relationship E-b = a + b log c(NaCl) held in all cases, with constants a and b, however, being dependent on the zinc content of the alloy and on the chloride concentration. The corrosion resistance of Cu-xZn alloys was less than that of copper metal but significantly greater than that of zinc.
10.1007-s10800-005-9025-7	2	corrosion; surface; film; electrochemical; films; spectroscopy; layer; current; solution; potential; resistance; composition; x-ray; ions; showed	A new bath formulation was developed, which allowed deposition of copper-rich Cu-Ni-P alloys in electroless acidic solutions in the absence of formaldehyde. The reducing agent was sodium hypophosphite. Though cupric ions do not catalyse the oxidation of hypophosphite, we show that, in the presence of a low concentration of Ni(II) species, it is possible, even at low pHs, to induce the reduction of the cupric species. A very strong preferential deposition of copper was observed, which gives Cu-Ni-P layers with copper content up to 97 wt%. The phosphorus content decreased from 13% to 1% with increasing copper content. The plating rate decreased when the copper sulfate concentration in the solution increased. It increased with increasing pH or temperature, but the influence was less pronounced than in alkaline solutions. Compact layers were obtained with a nodular morphology which did not markedly changed with composition.
10.1007-s10800-005-9101-z	2	corrosion; surface; film; electrochemical; films; spectroscopy; layer; current; solution; potential; resistance; composition; x-ray; ions; showed	A comparative study of the corrosion resistance of a bare Cu-10 Ni alloy and a Cu-10 Ni alloy protected by sodium-diethyl-dithiocarbamate (NaEt(2)dtc) has been undertaken. The experimental conditions varied from quiescent natural seawater to seawater subjected to jet impingement of different fluid velocities. The mechanism of inhibitor action has been suggested that includes the formation of a surface chelate compound between the dissolving metal ion and the (Et(2)dtc)(-) ligand, as well as formation of a 3-D ternary surface complex. The surface layer that incorporates both the inhibitor and the cuprous oxide, represented by the structure: Cu-Ni/Cu2O/Cu(II) organic complex/seawater has shown an excellent protective performance with efficiency > 90% under stagnant and fluid impingement conditions.
10.1007-s10800-005-9110-y	2	corrosion; surface; film; electrochemical; films; spectroscopy; layer; current; solution; potential; resistance; composition; x-ray; ions; showed	Surface oxides grown on copper and copper-nickel alloys (UNS 72000 and UNS 70600) in aerated borax-borate buffer solution of pH 7.7 were characterized using various experimental techniques. Their influence on the mechanism of oxygen reduction was also investigated. The composition of the passive films formed in situ on the different materials was studied using differential reflectance spectroscopy. Electrochemical techniques such as voltammetry and potentiodynamic reductions, as well as hydrodynamic tools such as the rotating disk electrode were used to characterize the kinetic parameters of the oxygen reduction reaction. The results show that the addition of Ni to Cu to form copper-nickel alloys changes the composition of the surface film. As the amount of Ni in the alloy increases, the proportion of Cu(I) compounds decreases, and Ni(II) compounds are incorporated into the film structure. The films anodically grown at 0.5 V on Cu70Ni30 tend to be thinner but more resistive. This is supported by results from reflectance and impedance spectroscopy. The kinetics of oxygen reduction follows a four-electron path on surface-free films, independently of the Ni-content in the alloy.
10.1007-s10800-006-9278-9	2	corrosion; surface; film; electrochemical; films; spectroscopy; layer; current; solution; potential; resistance; composition; x-ray; ions; showed	Copper-zinc alloy coatings were deposited on mild steel substrates using sodium citrate electrolytes at room temperature and under direct current. For the bath composition studied, factorial design was used to verify the influence of deposition parameters, such as current density and mechanical stirring, on the cathodic efficiency, the contents of copper and zinc, and the amount of hydrogen evolution. Moreover, the four responses were simultaneously studied by using an optimization methodology. The results suggest that the optimum point for reaching good quality copper-zinc alloy deposits from the proposed citrate electrolytes are 29 A m(-2) and 247 rpm for bath 3 and 13 A m(-2) and 67 rpm for bath 4. Applying these conditions, a yellow-reddish coating was obtained from bath 3, while a bright red deposit was produced from bath 4.
10.1007-s10800-008-9630-3	2	corrosion; surface; film; electrochemical; films; spectroscopy; layer; current; solution; potential; resistance; composition; x-ray; ions; showed	Copper-cobalt alloy coatings were deposited on mild steel substrates using sodium citrate electrolytes at room temperature and under direct current. A set of cathodic polarization curves was plotted by varying the mechanical stirring speed of the solution (0-400 rpm), using a range of current densities during the electrodeposition experiments. Factorial design was used to verify the influence of these deposition parameters on the cathodic efficiency, the copper and cobalt content in the coating, the corrosion current density of the coating/substrate system, and the efficiency of the coating in protecting the substrate. The electroplating experiments showed that, with the studied bath composition, high stirring speed and low current density lead to greater cathodic current efficiency and copper-rich coatings. On the other hand, high current density and low stirring speed yields coatings with high cobalt content and a lower cathodic efficiency. Our results show that the studied parameters affect the corrosion current density and the coating efficiency of the coating/substrate system in opposite ways. The best results were obtained increasing the current density and decreasing the mechanical stirring speed. Additionally, three samples were produced in selected deposition conditions. The coatings morphologies were compact, and their grain sizes seemed to enlarge with increasing stirring speed and decreasing current density.
10.1007-s10800-009-9899-x	2	corrosion; surface; film; electrochemical; films; spectroscopy; layer; current; solution; potential; resistance; composition; x-ray; ions; showed	Cu-Ni alloy coatings on copper substrate by the brush-plating process have been investigated using XRD and AFM. The X-Ray diffraction analysis revealed that the brush-plated Cu-Ni alloy was heterogeneous and composed of cubic Cu3.8Ni phases. Uniform surface coverage of the substrate by granular morphology was observed from AFM. The corrosion protection performance of the brush-plated Cu-Ni alloy on copper substrate has been assessed using electrochemical corrosion tests. These results indicated a high charge transfer and low I (corr) for the alloy system compared with copper deposits and the copper substrate.
10.1007-s10800-009-9918-y	2	corrosion; surface; film; electrochemical; films; spectroscopy; layer; current; solution; potential; resistance; composition; x-ray; ions; showed	The use of binary copper-nickel (Cu-Ni) codeposition from a complexing citrate electrolyte is proposed as a convenient model system for simple, rapid and inexpensive characterization of local mass-transfer limitations arising in the production of ternary copper-indium-selenium (CIS) thin films. Both the Cu-Ni and the CIS systems have been investigated in a small pilot cell and deposit thickness and composition distributions on a 5 x 5 cm(2) cathode have been compared. The experimental comparison confirms that the mass-transfer characteristics measured for copper deposition in the binary Cu-Ni codeposition system offer an excellent representation of the mass-transfer-limited deposition of copper and selenium in the ternary CIS system. The binary Cu-Ni system presents a number of advantages for process development, among which the possibility of operating at neutral pH and being much easier to handle, less expensive and less toxic than the CIS system. The results of the study presented here, although targeted to CIS production, may also be of use for the development of other electrodeposition processes in which one or more electro-active species are reduced under mass-transfer control.
10.1007-s10800-010-0251-2	2	corrosion; surface; film; electrochemical; films; spectroscopy; layer; current; solution; potential; resistance; composition; x-ray; ions; showed	This study examined the influence of citrate and tartrate as complexing agents on the electrodeposition and surface morphology of Cu-Ni layers. The alloys obtained in the tartaric acid and sulphate baths were nobler than those obtained in the citric acid/citrate and citric acid/citrate/tartaric acid media. The results indicated that the complexing medium influences the nobility and the type of mass transport of the alloy formed. The morphology of the electrodeposited Cu-Ni layers changed from a rather porous appearance in the absence of the complexing agents to nodular, cracked mud and cauliflower appearances for the citric acid/sodium citrate/sodium sulphate medium, tartaric acid/sodium sulphate medium and citric acid/sodium citrate/tartaric acid/sodium sulphate medium, respectively. The chemical composition of the Cu-Ni layers revealed the preferential deposition of copper. The ultraviolet-visible spectrophotometry measurements indicated the occurrence of the d-d type transition, regardless of the complexing medium employed.
10.1007-s10800-013-0642-2	2	corrosion; surface; film; electrochemical; films; spectroscopy; layer; current; solution; potential; resistance; composition; x-ray; ions; showed	Adsorption of sulphate anions onto polycrystalline pure copper, pure nickel and two copper-nickel alloys was explored by performing zero charge potential E (PZC) measurements. E (PZC) measurements were performed by differential capacitance analysis using single-frequency electrochemical impedance spectroscopy. E (PZC) and surface charge of the studied materials were analysed for different surface states: bare-immediately after cathodic polarisation and after 5 h of immersion in a 0.1 M Na2SO4 solution. According to the surface state and nature of the studied materials, the choice of the appropriate measuring frequency was investigated. Specific methodologies dedicated to the study of electrode/electrolyte interfaces are then presented for bare metal, metals covered by corrosion products and metals covered by passive film. In the presence of passive film, the space charge capacitance interferes with the differential capacitance measurements, and its influence is discussed in the framework of semiconductor electrochemistry.
10.1007-s10800-017-1069-y	2	corrosion; surface; film; electrochemical; films; spectroscopy; layer; current; solution; potential; resistance; composition; x-ray; ions; showed	Cu-Zn alloy films have been electrodeposited directly from their oxide precursors in choline chloride (ChCl)/urea-based deep eutectic solvent (DES). The reaction mechanism and the influence of the cathodic potential on the characteristics of the Cu-Zn alloy films are studied. Cyclic voltammetry and energy dispersive spectroscopy analyses reveal that the reduction of Cu(II) species relatively more preferentially occurs in comparison with the reduction of Zn(II) species, and Cu-Zn codeposition process can be controlled in the DES. Chronoamperometric investigation further confirms that the electrodeposition of Cu-Zn alloy on a Fe electrode follows the three-dimensional instantaneous nucleation-growth process. The micro/nanostructured Cu-Zn alloy films with different phase compositions can be facilely produced by controlling the cathodic potential. The obtained Cu-Zn alloy films typically exhibit enhanced corrosion resistances in 3 wt% NaCl aqueous solution. It is suggested that Cu-Zn alloy films can be sustainably electrodeposited from their abundant and inexpensive oxide precursors in DES. Micro/nanostructured Cu-Zn alloy films have been electrodeposited directly from CuO and ZnO precursors in deep eutectic solvent (DES), the electrochemical reaction mechanism and the nucleation-growth process of Cu-Zn alloy in the DES are investigated. [GRAPHICS] .
10.1007-s10800-018-1148-8	2	corrosion; surface; film; electrochemical; films; spectroscopy; layer; current; solution; potential; resistance; composition; x-ray; ions; showed	In this work, it investigated a non-cyanide imitation gold plating system, namely a hydroxyethylidene diphosphonic acid system. The bath in this system is less toxic and less expensive, and the decorative quality of the coating can be maintained with this system. The effects of four N-based additives, namely triethanolamine (TEA), ammonium fluoride (AF), ammonia triacetic acid (NTA), and polyacrylamide (PAM), on the performance of the Cu-Zn-Sn alloy coating were studied. The results indicate that TEA can be used as an auxiliary complexing agent to promote anodic dissolution, improve the dispersibility of the bath, and control the colour and brightness of the coating. The carboxylic acid group of NTA is easily discharged in the cathode, inducing the hydrogen evolution reaction, which results in a blackened and irregular coating surface. In addition to inorganic amines, AF also contains fluoride ions, which enable the formation of uniformly sized particles, dense crystals, and a compactly arranged coating, and may promote the formation of a yellow coating. The long chain of PAM prevents the migration of Cu2+ ions in the solution, which causes a decrease in the anodic stripping peak current and thus adversely affects the electrode interface. The mechanism of the four additives in the electroplating process was studied, and the results may provide theoretical guidance for selecting additives for the Cu-Zn-Sn electroplating process. [GRAPHICS] .
10.1007-s10800-019-01316-z	2	corrosion; surface; film; electrochemical; films; spectroscopy; layer; current; solution; potential; resistance; composition; x-ray; ions; showed	A non-cyanide rose golden electroplating system was investigated in this work. The electroplated layer of Cu-Zn-Sn alloy was also investigated using a disodium ethylenediamine tetraacetate (EDTA2Na) system, in which CuSO(4)5H(2)O, ZnSO(4)7H(2)O and Na(2)SnO(3)3H(2)O were the main salts. EDTA2Na acted as a complexing agent. Finally, NaOH acted as a buffering agent in the electroplating solution. The effects of different electroplating solutions on colour, micro-topography, composition and phase structure of the electroplated layer was analysed by photo analysis, SEM, EDS and XRD. Meanwhile, different electroplating solutions were analysed and compared by electrochemical analysis and UV-Vis, FTIR and NMR spectroscopy. A rose golden electroplated layer of Cu-Zn-Sn alloy could be obtained by adjusting the amount of the main salts. The composition of the electroplated layer was 98.81% Cu, 0.77% Zn and 0.42% Sn. Moreover, the electroplated layer was composed of regular 50-100nm particles. The composition of the ternary alloy-electroplated layer was Cu, Cu5Zn8 and Cu10Sn3 phase. At the same time, the cathode only had a single deposition peak at -1.22V by electrochemical analysis of the electroplating solution. UV, IR and NMR analyses show that a chelate was formed with EDTA2Na and metal ions in an alkaline environment. These results may provide a theoretical guidance for a new technology for Cu-Zn-Sn alloy electrodeposition. [GRAPHICS] .
10.1007-s10800-020-01398-0	-1		Using this co-electrodeposition method, we successfully prepared a Cu-Ni alloy film at a low temperature. The results of this study showed that when Cu-Ni film is co-deposited at-1.3 V (vs. Ag/AgCl) in a solution with a composition ratio of Ni to Cu ions of 90:10, the atomic percentage of Cu to Ni necessary to form the Cu-Ni alloy is approximately one. Electroplated for 20 min, the thickness of the Cu-Ni film grows to around 10 mu m, and the resistance is approximately 103 m omega. In this work, the samples were annealed at 700, 800, and 900 degrees C for 30 min, respectively. The resistance increased gradually with increases in the annealing temperature because of the increasing entropy of the Cu-Ni alloy. On the contrary, the TCR decreased gradually with increases in the annealing temperature. The sample annealed at 900 degrees C exhibited a single crystal FCC Cu-Ni alloy with a lattice constant of 3.62 angstrom, corresponding to a very low TCR of around 50 ppm/ degrees C. Graphic
10.1007-s10800-020-01405-4	2	corrosion; surface; film; electrochemical; films; spectroscopy; layer; current; solution; potential; resistance; composition; x-ray; ions; showed	The electrodeposition of Cu-Zn-Sn ternary alloys on stainless steel from a cyanide-free alkaline electrolyte containing hydroxyethylidene diphosphonic acid (HEDP) was investigated. Four hydroxyl-containing additives, namely methanol (MET), ethylene glycol (EG), glycerol (GLY), and mannitol (MAN), were added to an HEDP bath, and the effects of the number of hydroxyl groups on the codeposition of Cu-Zn-Sn ternary alloys were compared. Cu-Zn-Sn codeposition occurred at-0.53 V-vs.Hg|HgO. The hydroxyl-containing additives were beneficial to promote the codeposition of Cu-Zn-Sn, since they can complex with metal ions and act as auxiliary complexing agents. The scanning electron microscopy (SEM) analysis showed that the smallest grain size of 0.1 mu m was obtained from the bath containing MAN. In addition to being smaller than the others, these coatings had uniform particle sizes. The energy-dispersive X-ray spectroscopy (EDS) analysis indicated that the composition of the Cu-Zn-Sn coatings obtained from the bath containing MAN was 73.293 wt% Cu, 26.079 wt% Zn, and 0.629 wt% Sn, and these coatings were golden in color. X-ray diffraction (XRD) showed that the Cu-Zn-Sn coatings were crystalline and were composed of a mixture of Cu, Zn, Cu5Zn8, Cu20Sn6, and Cu39Sn11 phases, indicating the formation of Cu-Zn-Sn ternary alloys. These results may provide theoretical guidance for an electrodeposition technology of Cu-Zn-Sn ternary alloys from a new cyanide-free alkaline electrolyte.
10.1007-s10800-023-01936-6	2	corrosion; surface; film; electrochemical; films; spectroscopy; layer; current; solution; potential; resistance; composition; x-ray; ions; showed	The inhibitive effect against copper-alloy corrosion in NaCl 3 wt% of a non-toxic compound, namely 5-Phenyl-1H-tetrazole (PT), is probed and compared with the performance of the most used and toxic 1H-Benzotriazole (BTA), by using a multi-technique approach . Electrochemical impedance spectroscopy and potentiodynamic polarisation measurements, at different inhibitors concentrations, are performed in order to evaluate the best inhibition efficiency (IE%) and the optimum concentration of the inhibitors. The inhibition efficiencies of PT (IE = 94.7-96.1%) and BTA (IE = 99.5-99.9%) are comparable, with the advantage that PT acts at a much lower concentration (1 mM respect to 10 mM). To shed light on the inhibition mechanism at the early stage of the corrosion (2 h), we investigate the samples surfaces composition and morphology by X-ray photoelectron spectroscopy, micro-Raman spectroscopy and atomic force microscopy. Different inhibition mechanism and patina composition are observed and commented for the two inhibitors. The reported experimental tests suggest PT as a promising candidate for replacing toxic BTA in the prevention of bronze archaeological and artistic objects corrosion. [GRAPHICS] .
10.1007-s10853-005-1935-6	-1		The surface tension of liquid binary alloys of the Cu-Ni-Fe system is measured by using the oscillating drop technique. The samples are processed contactlessly in an electromagnetic levitation chamber and hence, considerably large undercooling can be achieved. The alloys and the pure elements copper, nickel, and iron are investigated at various temperatures above and below their melting points. In addition, the surface tensions are also investigated as a function of the concentrations at constant temperature. The values agree well with predictions from theory and an analysis of the segregational behaviour is performed. (C) 2005 Springer Science + Business Media, Inc.
10.1007-s10853-005-1973-0	-1		Cu-TiCx composites have been made self-propagating high temperature synthesis of Cu-Ti-C mixtures. It was found that as the C/Ti ratio decreases, wetting of the carbide, by what is effectively a molten Cu-Ti alloy, is improved and the distribution of the carbides in the master-alloy becomes ideal for subsequent dispersion, i.e. discrete particles are formed. Increasing quantity of Cu in the reactants from 10 to 50 wt% Cu had a similar effect to decreasing the C/Ti ratio and enabled the size of the TiCx particles to be varied in the approximate range 20-0.5 mu m. Incorporation and dispersion of the master alloy into molten copper was possible when the C/Ti ratio in the products was below approximately 0.73, which agreed well with contact angle data in the literature. (C) 2005 Springer Science + Business Media, Inc.
10.1007-s10853-005-2673-5	-1		A new method is presented for the measurement of equilibrium dihedral angles in intergranular inclusions, and illustrated with pure copper containing 1 wt% lead. The method is based on the selective dissolution of inclusions visible along a polished metallographic section. Scanning electron microscopy stereo image pairs are then taken and processed so as to enable a three-dimensional digital reconstruction of the inclusion/matrix interface along each inclusion. Spherical caps describing the Cu/Pb interface over non-facetted orientations are then fitted to the measured digital inclusion envelope reconstructions. Knowing the center and radius of these spheres, the true dihedral angle of each specific inclusion can then be deduced with good precision. It is found that the true dihedral angle in the Cu/Pb alloy is not a unique function of temperature, reflecting the (known) anisotropy of high-angle grain boundary energy in copper. (c) 2005 Springer Science + Business Media, Inc.
10.1007-s10853-005-3151-9	4	transformation; martensite; martensitic; phase; shape; beta; memory; shape memory; temperature; temperatures; martensitic transformation; gamma; transformation temperatures; effect; thermal	The reverse martensitic transformation in the Cu-10 wt%Al-6 wt%Ag alloy was studied by classical differential thermal analysis (IDTA), scanning electron microscopy (SEM), energy dispersive X-ray analysis (EDX) and X-ray diffractometry (XRD). The results indicated that the presence of Ag in the Cu-10%Al alloy is responsible for the separation of the competitive reactions that occur during the reverse martensitic transformation and is also associated to an increase in the disordering degree at high temperatures, when compared with alloys without Ag addition. (c) 2005 Springer Science + Business Media, Inc.
10.1007-s10853-005-3168-0	11	glass; bulk; metallic; bulk metallic; gfa; bmg; glassy; metallic glass; ability; bulk metallic glass; amorphous; addition; crystallization; mm; glass-forming	The mechanical behavior of the WC particulate (WCp) reinforced Cu47Ti33Zr11Ni6Sn2Si1 bulk metallic glass (BMG) matrix composites has been examined. The mechanical properties are improved with increasing WCp content up to 20 wt%. The ultimate compression strength and plastic strain of the composite containing 20 wt% WCp are 2.4 GPa and 2.4%, while those of the monolithic BMG are 1.6 GPa and similar to 0%, respectively. The multiple shear band formation and crack deflections through WC particles have been identified as the main mechanism for the improved toughness. (c) 2005 Springer Science + Business Media, Inc.
10.1007-s10853-006-0295-1	4	transformation; martensite; martensitic; phase; shape; beta; memory; shape memory; temperature; temperatures; martensitic transformation; gamma; transformation temperatures; effect; thermal	Thermal aging between 250 and 500 degrees C of ordered beta phase in a polycrystalline Cu-Al-Be shape memory alloy were performed, and the formation of phase gamma(2) was studied with optical and transmission electron microscopies and XRD techniques. The growth of gamma(2) phase shows a polynomial behavior, and Avrami curves as well as a Time-Temperature-Transformation diagram were constructed from these results. In addition, the formation of stable gamma(2) precipitates was studied in aged Cu-Al-Be ribbons. The presence of alpha regions surrounding gamma(2) precipitates for longer aging times at higher temperatures was observed, giving a consistent precipitation scheme.
10.1007-s10853-006-0385-0	16	wear; composite; composites; powders; milling; particles; powder; wt; sliding; friction; hardness; matrix; mechanical; surface; properties	Powder metal processing permits development of new composites with specific properties required for demanding applications. Complex shaped machine elements like gears and bearings are made of powder metallurgy technique economically. In many applications these machine elements operate under unlubricated conditions and there is a need for materials with good friction and wear characteristics, strength and modulus. In the present study, Fe-C-Cu-Ni alloys with solid lubricant, MoS2, were developed using a simple single stage compaction and sintering. The microstructure, strength, hardness and tribo behavior of the composites were evaluated. The friction and wear characteristics were evaluated using pin-on-disc type tribo test machine. Addition of solid lubricant improved the compressibility and thereby the density of the compacts. Presence of the secondary sulphide phases in the as-sintered compacts improves the hardness and strength . The coefficient of friction and wear loss decreased with addition of MoS2. A simple wear model is proposed to predict the wear loss in these composites. The model predicts wear loss values that are in agreement with the experimental data.
10.1007-s10853-006-0501-1	6	grain; deformation; strain; strength; dislocation; cu-; tensile; size; ecap; grain size; sfe; ductility; hardening; high; stress	The tensile behaviors of the ultrafine-grained (UFG) pure copper prepared by cold rolling have been investigated. The UFG-Cu exhibited high strengths and low ductility. The ductile dimple-like fracture surfaces and persistent-slip-bands (PSBs)-like local shear bands in the tension-deformed UFG-Cu were observed, both of which typically spanned tens of grain sizes. This observation indicated that the fracture mechanisms operated at a larger scale than the grain size and eventually involved collective grain activities. Moreover, localized shear bands provided the experimental evidence to the localized plastic deformation, which was the one of the dominant reasons, causing the low ductility in the UFG-Cu.
10.1007-s10853-006-0986-7	-1		The requirement of thermal stability of nanocrystalline materials can be fulfilled with a composite approach . However, utilizing a two-phase approach includes additional constraints concerning the synthesis and processing, especially of massive nanostructured materials. Here, the potential of deformation processing for synthesizing nanoscale composite structures with uniform microstructures in bulk shape is analyzed for a series of Cu-rich alloys. The results are discussed with respect of governing materials properties that determine the feasibility of a composite approach in combination with severe plastic deformation to obtain massive nano-composite materials with high thermal stability.
10.1007-s10853-006-1096-2	-1		Nanomaterials can easily be prepared as thin films and powders, but are much harder to prepare in bulk form. Nanostructured materials are prepared mainly by consolidation, electrodeposition, and deformation. These processing techniques have problems such as porosity, contamination, high cost, and limitations in refining the grain size. Since most bulk engineering metals are initially prepared by casting, we developed a casting technique, flux-melting and melt-solidification, to prepare bulk nanostructured alloys. The casting technique has such advantages as simplicity, low cost, and full density. In our method, Ag-Cu alloys were melted in B2O3 flux, which removed most of the impurities, mainly oxides, in the melts. Upon solidifying the melt at a relatively slow cooling rate on the order of 10(1)-10(2) K/s a large undercooling of similar to 0.25 T-m (where T-m is the melting temperature) was achieved. This large undercooling leads to the formation of bulk nanostructured Ag-Cu alloys composed of alternative Ag/Cu lamella and nanocrystals, both similar to 50 nm in dimension. Our liquid-processed alloys are fully dense and relatively free from contamination. The nanostructured Ag-Cu alloys have similar yield strength in tension and in compression. The as-quenched alloys have yield strength of 400 MPa, ultimate tensile strength (UTS) of 550 MPa, and plastic elongation of similar to 8%. The UTS was further increased to similar to 830 MPa after the as-quenched alloy rod was cold drawn to a strain of similar to 2. The nanostructured Ag-Cu alloys show a high electrical conductivity (similar to 80% that of International Annealed Copper Standard), a slight strain hardening (strain-hardening coefficient of 0.10), and a high thermal stability up to a reduced temperature of 2/3 T-m. Some of these behaviors are different than those found in previous bulk nanostructured materials synthesized by solid state methods, and are explained based on the unique nanostructures achieved by our flux-melting and melt-solidification technique.
10.1007-s10853-006-7941-5	15	aging; strength; conductivity; electrical conductivity; electrical; mpa; treatment; strengthening; degrees; cu-; cold; precipitation; tensile strength; tensile; iacs	Effect of doping with alloying element Zr on the structure, the electrical resistivity and the strength of deformation-processed Cu-Fe in-situ composites were studied respectively by scanning electron microscope (SEM), transmission electronic microscope (TEM), material test system (MTS) and resistance measuring apparatus. The experimental results show that the ultimate tensile strength (UTS) and the conductivity of Cu-11.5% Fe-Zr wire cold drawn to the drawing strain eta = 7.57 with intermediate heat treatments were observed to be 824 MPa and 61.4% IACS respectively, and those of Cu-11.5% Fe were 752 MPa and 64.6% IACS. Doping Zr can improve the thermal stability of Cu-Fe composites. The strength of Cu-Fe-Zr wire does not drop more rapidly at higher annealing temperatures (above 300 degrees C) than that of Cu-Fe wire. (c) 2006 Springer Science + Business Media, Inc.
10.1007-s10853-007-1724-5	-1		Cu59.6Zr36.9Al3.5 alloy are prepared by laser-induced combustion synthesis technology. The microstructure and phases formed of the product is studied by XRD and TEM. The product consists of mixtures of amorphous and crystalline phases, mainly(alpha-Zr, Zr2Cu, Zr10Cu7 and Cu8Zr3. The amorphous and nanocrystalline phases content over 50% in volume estimated from the broad peak in the XRD spectrum. TEM and HRTEM results show that the microstructure is characterized by inhomogeneously distributed amorphous, nano Zr2Cu, relatively gross (-100 nm) Zr2Cu, and large grain Cu10Zr7.
10.1007-s10853-007-1843-z	12	thermodynamic; ternary; phase; data; experimental; equilibria; phase equilibria; liquid; binary; experimental data; calculated; phases; literature; model; calphad	A theory based on calculation of phase diagrams in the binary systems was developed that describes Gibbs-Thomson effect. In this model effect of both interfacial energy and interface confinement (Laplace-Young pressure) are included in energy shift of alloys and phases. By using the CALPHAD model, interfacial energy of Cu4Ti precipitates in Cu-Ti system was obtained which shows better consistency with experimental results of Gibbs-Thomson effect of 10-20 nm radius precipitates.
10.1007-s10853-007-1879-0	-1		The development of strongly cube textured Cu based substrates is important in the cost effective production of long lengths of high temperature superconducting cables. The present paper reports textures (deformation and recrystallisation) development in pure Cu, Cu-Al, Cu-Mn (with a solute content of 1-3 at%) and Cu-35 at% Ni alloys.
10.1007-s10853-007-2233-2	-1		Aging behavior of Cu-3 at% Ti-4 at% Al alloy at 723 K has been examined from mechanical, electrical, and microstructural points of view. Compared with binary Cu-3 at% Ti alloy, the electrical conductivity improved six times to about 6%IACS (international annealed copper standard); whereas the peak hardness decreased from 280 to 180 HV. The major strengthening phase is the tetragonal alpha-Cu(4)Ti, which forms not via spinodal decomposition but based on the nucleation and growth mechanism. The precipitates grow in the c direction of the tetragonal phase, which lies along one of the < 100 > axes of the matrix fcc Cu phase. This growth mode minimizes the strain energy arising from the lattice mismatch of about 2% between the matrix and precipitate; and results in a square rod shape, which reaches about 50 nm in length after 100 h anneal. Another precipitating phase is AlCu(2)Ti (D0(3), Strukturbericht notation), with the major habit plane close to {110} of the fcc Cu matrix. The orientation relationship was not definitely determined, but it was found that the angle between the 100 and 110 poles of the matrix and precipitates, respectively, is about 5 degrees, while the angle between the two 001 axes being about 7 degrees. It was suggested that the formation of this ternary phase reduced the solute Ti concentration, leading to the decrease in the resistivity.
10.1007-s10853-007-2290-6	-1		The effect of coherency on coarsening of fcc Co-Fe precipitates in a Cu-1.47 wt%Co-0.56 wt%Fe (Co : Fe = 7:3 in atomic ratio) alloy aged at 873-973 K has been studied by measuring both the precipitate size by transmission electron microscopy and the solute concentration in the Cu matrix by electrical resistivity measurements. The precipitate phase consists of 7 parts of Co and 3 parts of Fe in atomic ratio, irrespective of the precipitate size. The precipitates smaller than about 8 nm in radius are coherent with the Cu-matrix. When the average precipitate radius is over 18 nm, all the precipitates become semi-coherent. The coarsening rates are not affected by the coherency of the precipitates. The precipitate/matrix interface energy gamma has been derived, independently of the diffusivities of solute atoms using a coarsening model developed by Kuehmann and Voorhees for ternary systems. The precipitates are coherent or semi-coherent with the matrix, the experimentally obtained value of gamma is 0.2 J/m(2) stop. This value lies between the reported values of gamma = 0.15 J/m(2) stop for Co precipitates and gamma = 0.25 J/m(2) stop for gamma-Fe precipitates.
10.1007-s10853-008-2540-2	12	thermodynamic; ternary; phase; data; experimental; equilibria; phase equilibria; liquid; binary; experimental data; calculated; phases; literature; model; calphad	Cu-Co-Fe alloys undercooled below a certain temperature display demixing of the liquid, followed by coagulation before dendritic solidification. In this article high temperature phase equilibria in Cu-Co-Fe samples have been precisely determined by DSC. Special attention has been paid to the liquid-liquid phase separation and on its effect on the formation of microstructures. The measured transformation temperatures have also been used to update the description of the ternary phase diagram.
10.1007-s10853-008-2634-x	-1		A series of CuZr binary alloys with wide composition range were fabricated through ARB and HPT techniques using pure Cu and Zr metals as the starting materials. Bulk alloy sheets with thickness of about 0.8 mm after ARB process and alloy disks with 0.30 mm in thickness and 10 mm in diameter after HPT process can be obtained, respectively. The structures of all the alloys were found to be gradually refined with the increase of ARB cycles or HPT rotations. As a result, nanoscale multiple-layered structure was formed for the 10 cycled ARBed specimens, which could partially transform into amorphous phase during subsequent low temperature annealing. While for the as-HPTed sample, the alloy was completely amorphized after 20 rotations without any heat treatment. The thermal stabilities of the amorphous alloys were studied. The deformation behavior and the amorphization mechanism during the ARB and HPT process were put forward and discussed.
10.1007-s10853-008-2802-z	6	grain; deformation; strain; strength; dislocation; cu-; tensile; size; ecap; grain size; sfe; ductility; hardening; high; stress	The particle-strengthened Cu-8 at%Cr-4 at%Nb alloy is processed by consolidation of atomized powders followed by extrusion to obtain bars and rolling to produce sheets. Comparison of copper matrix grain and second-phase particle structures in both extruded and rolled Cu-8Cr-4Nb was performed. Extruded material displayed locally banded arrangements of Cr2Nb particles, while the distribution of particles was more uniform in rolled material. Mean Cr2Nb particle sizes were found to be essentially the same for both processing methods. Non-spherical particles in the extruded alloy showed some preferred orientation, whereas the rolled material displayed a more uniform particle orientation distribution. Extruded material exhibited a dual grain size distribution with smaller grains in banded regions. The mean grain size of 1.36 mu m in extruded material was larger than the 0.65 mu m grain size of rolled material. A [101] texture was evident in extruded material, whereas the rolled material was only slightly textured along the [001] and [111] directions. The processing differences for the rolled and extruded forms give rise to different microstructures and hence higher creep strength for the extruded material in the temperature range of 773-923 K.
10.1007-s10853-008-2813-9	-1		The process of high-pressure torsion (HPT) was applied to control the size and distribution of ferromagnetic Co particles in a Cu-Co alloy. Electron probe microanalysis, X-ray diffraction analysis, and transmission electron microscopy confirmed that the Co particles were significantly refined through fragmentation and dissolved with intense straining by HPT. Magnetoresistance appeared by similar to 2.5% at 77 K with an isotropic feature corresponding to giant magnetoresistance (GMR). It is demonstrated that HPT is a potential process for creating GMR in the Cu-Co alloy prepared by conventional ingot metallurgy.
10.1007-s10853-008-3194-9	-1		Microstructure fracture and mechanical properties of Cu-based bulk metallic glass alloys were investigated. Centrifugal casting into copper molds were used to manufacture basic Cu47Ti33Zr11Ni9, and modified Cu47Ti33Zr11Ni7Si1Sn1 alloys. Although the alloys show an amorphous structure, TEM images revealed the formation of nanoparticles. At room temperature compression tests reveal fracture strength of 2000 MPa, elastic modulus of 127 GPa, and 1.8% fracture strain for the unmodified basic alloy. Whereas the modified alloy exhibits a fracture strength of 2179 MPa, elastic modulus reaches 123 GPa, and 2.4% fracture strain. So, with the addition of 1 at% Si and Sn, the fracture strength improves by 9% and the fracture strain improves by 25%, but the fracture behavior under compression conditions exhibits a conical shape similar to that produced by tensile testing of ductile alloys. A proposed fracture mechanism explaining the formation of the conical fracture surface was adopted. The formation of homogeneously distributed nano-size (2-5 nm) precipitates changes the mode of fracture of the metallic glass from single to multiple shear plane modes leading to the conical shape fracture surface morphology.
10.1007-s10853-009-3530-8	-1		In the present investigation, we report the formation of gamma-brass type phase in the rapidly quenched Cu50Ga30Mg5Ti15 and Cu50Al30Mg5Ti15 alloys. Rapid solidification of Cu50Ga30Mg5Ti15 alloy shows the formation of simple cubic gamma-brass type phase (a = 0.863 nm), which on annealing at 1,023 K for 60 h transforms to disordered type gamma-brass phase (a = 0.879 nm). It has been observed that intensity modulation of electron diffraction spots corresponding to simple cubic gamma-brass phase is similar to the intensity modulation observed in the mirror orientation of icosahedral quasicrystalline phase. Contrary to the crystalline phase formation in Cu-Ga-Mg-Ti alloy, rapid solidification of Cu50Al30Mg5Ti15 shows the formation of amorphous and nanocrystalline bcc gamma-brass type phase (a = 0.870 nm), which on annealing transforms to ordered gamma-brass type phase (a = 0.872 nm). The structural and microstructural characterization was done through X-ray diffraction and transmission electron microscopy.
10.1007-s10853-009-3821-0	4	transformation; martensite; martensitic; phase; shape; beta; memory; shape memory; temperature; temperatures; martensitic transformation; gamma; transformation temperatures; effect; thermal	The isothermal treatment of the beta phase in some Cu-based alloys produces its decomposition by an earlier precipitation of gamma phase. During their growth, by means of a diffusion-controlled process, the precipitates show evidences of morphological changes. In the first stages and for a Cu-Zn-Al alloy, the morphology is spherical and cuboidal, but develops more complex shapes such as dendrites, owing to composition fields, interphase overlapping, crystallography characteristics, and relative orientation. In this work, a dendritic gamma precipitate characterization is done and morphological theoretical predictions are applied, for Cu-Zn-Al and Cu-Al-Be alloys.
10.1007-s10853-010-4657-3	6	grain; deformation; strain; strength; dislocation; cu-; tensile; size; ecap; grain size; sfe; ductility; hardening; high; stress	The article describes the combined effects of grain size and second phase particles on mechanical properties of CuCrZr alloy subjected to SPD processing and ageing in two sequences: (i) SPD processing followed by ageing and (ii) SPD processing of samples aged prior to deformation. It was revealed that each of these strengthening mechanisms acting alone gives a significant increase in mechanical strength (5 and 10 times in the case of ageing and SPD processing, respectively). However, it has been found in the present study that the strength of samples subjected to grain refinement and precipitation hardening is not a direct sum of the strengthening brought about by these two strengthening mechanisms acting alone. This finding is discussed in terms of the inter-dependence of grain size-particle strengthening in SPD nano-metals.
10.1007-s10853-010-4764-1	-1		This study presents evidence that the microstructural stability of fine-grained and nanocrystalline Cu is improved by alloying with Sb. Experimentally, Cu100-xSbx alloys are cast in three compositions (Cu-0.0, 0.2, and 0.5 at% Sb) and extruded into fine-grained form (with average grain diameter of 350 nm) by equal channel angular extrusion. Alloying the Cu specimens with Sb causes an increase in the temperature associated with microstructural evolution to 400 degrees C, compared to 250 degrees C for pure Cu. This is verified by measurements of microhardness, ultimate tensile strength, and grain size using transmission electron microscopy. Complementary molecular dynamics (MD) simulations are performed on nanocrystalline Cu-Sb alloy models (with average grain diameter of 10 nm). MD simulations show fundamentally that Sb atoms placed at random sites along the grain boundaries can stabilize the nanocrystalline Cu microstructure during an accelerated annealing process.
10.1007-s10853-010-5087-y	-1		Owing to annealing at complete solid-solution temperatures around 1,000 K, Pd can quickly penetrate into Cu due to diffusion-induced recrystallization (DIR). To examine this penetration behavior, DIR in the Cu(Pd) system was experimentally observed in the present study. A diffusion bonding technique was used to prepare polycrystalline Cu/Pd/Cu diffusion couples. The diffusion couple was isothermally annealed at temperatures of T = 923-1,023 K for various times up to t = 176 h . During annealing, a region alloyed with Pd is produced in Cu from the Cu/Pd interface due to DIR. The concentration of Pd on the Pd-rich side in the DIR region remains almost constant independent of the annealing time but increases with increasing annealing temperature. On the other hand, the mean thickness of the DIR region increases with increasing annealing time. The growth rate of the DIR region is a monotonically increasing function of the annealing temperature. The experimental findings of the kinetics study were quantitatively analyzed using a mathematical model. The analysis satisfactorily reproduces the overall growth behavior of the DIR region.
10.1007-s10853-010-5189-6	0	solidification; phase; magnetic; magnetic field; undercooling; field; liquid; separation; peritectic; immiscible; cu-; dendrite; phase separation; microstructure; primary	Considering non-equilibrium solidification and its influence on subsequent near-equilibrium solidification together, the description of recalescence behavior in bulk undercooled Cu(70)Ni(30) alloy was adopted to predict the corresponding microstructure transition. The thermal plateau time for near-equilibrium solidification can be deduced directly with the calculation of non-equilibrium solid fraction formed in recalescence. On the basis of quantitative description for recalescence behavior, the non-equilibrium solid fraction, residual liquid fraction, dendrite broken-up time, and thermal plateau time can be determined as functions of initial undercooling. Then, a simple and accurate application of dendrite fragmentation model was performed as the grain refinement at both low- and high-undercooling originates from dendrite breakup. The predicted undercooling regions for the double grain refinement agree well with the experimental observation. Moreover, the change of grain morphology for the second grain refinement can be ascribed to the occurrence of recrystallization produced by the enhanced residual stress upon highly undercooled solidification.
10.1007-s10853-010-5232-7	-1		The effects of addition of 0.01 and 0.03 wt% Mg on the bend formability and strength of a Cu-1.8 wt% Be-0.21 wt% Co alloy aged at 320 A degrees C for 30 min have been investigated metallographically. The addition of Mg to the Cu-Be-Co alloy enhances the bend formability and strength of the alloy. The enhancement of strength is caused by the increase in volume fraction of gamma(1) precipitates in the Cu matrix. In bending of the alloys with and without 0.01 and 0.03 wt% Mg, a number of micro necks first arise along grain boundaries, and part of them grows, resulting in surface wrinkles, which finally lead to surface cracking. The cracking is initiated from voids formed by destruction of bar-like gamma precipitates in discontinuous precipitation (DP) cells and propagates along grain boundaries. The addition of Mg decreases the width of DP cells, resulting in better bend formability. This arises because smaller stress concentration due to less inhomogeneous deformation develops in cells and, as a result, destruction of the gamma precipitates in cells occurs less easily as the cell width decreases.
10.1007-s10853-010-5234-5	4	transformation; martensite; martensitic; phase; shape; beta; memory; shape memory; temperature; temperatures; martensitic transformation; gamma; transformation temperatures; effect; thermal	As well known, bismuth rapidly penetrates into copper grain boundaries at about 550 A degrees C and embrittles copper. In the experiments, the authors have used solid Bi2Te3 for the embrittlement of pure copper and copper-based solid solutions containing iron and silver. The investigated alloys were heated in the closed volume together with Bi2Te3 for a short time (5-90 min) at 570 A degrees C in the hydrogen atmosphere. Bi2Te3 did not contact with copper samples during annealing. After that, the samples were bent and grain boundary cracks were formed (with the depth about 10-500 mu m). Experiment showed that silver accelerates the embrittlement in the contrast to iron. The cracks in the silver-copper alloys were deeper than in the iron-copper ones. It was assumed that the depth of cracks is equal to the penetration depth . The reasons for this phenomenon were discussed in terms of the impurities effect on the grain boundary segregation.
10.1007-s10853-011-5312-3	-1		Copper alloys with different amounts of zinc were synthesized via high energy ball milling at liquid nitrogen and room temperature. Bulk samples were produced in situ by controlling the milling temperature. It is shown that temperature plays an important role in formation of artifact-free consolidated samples via its effect on defect formation and annihilation during the milling process. The mechanical behavior of Cu-Zn nanocrystalline alloys was examined using Vickers microhardness and tensile tests. The nanostructure of the alloys was investigated by X-ray diffraction (XRD) and transmission electron microscopy (TEM). The hardness results of processed alloys vary as a function of the alloying elements. Considering typical low ductility of nanocrystalline materials, the improved ductility with the high strength observed in these alloys suggests that they are artifact-free and may have several deformation mechanisms, which may include dislocation activity and nano-twinning.
10.1007-s10853-011-5672-8	-1		Liquidus temperatures in the Cu-Cr system at compositions of 10.0-72.7 at% Cr were determined using electromagnetic levitation melting. The present data agree with the prediction of a recent thermodynamic study of the system for compositions up to 20.0 at% Cr. However, they show large and positive deviations for other compositions. Microscopic studies reveal that compositions between 10.0 and 50.5 at% Cr solidified into a dendritic microstructure, whereas those between 55.9 and 72.7 at% Cr solidified into a droplet-shaped microstructure. The microstructure of the latter type provides direct evidence for the existence of a stable miscibility gap over Cr-rich compositions. Phase equilibria in the Cu-Cr system were calculated using the CALPHAD method. A novel phase diagram was proposed for the Cu-Cr system, which shows a monotectic reaction between compositions of 50.8 and 83.2 at% Cr at an invariant temperature of 2020 +/- 22 K. The novel phase diagram has reduced the discrepancies between the literature data.
10.1007-s10853-011-5768-1	6	grain; deformation; strain; strength; dislocation; cu-; tensile; size; ecap; grain size; sfe; ductility; hardening; high; stress	Substructural characteristics of Cu (99.97%) were examined after the Twist channel angular pressing (TCAP) process carried out at ambient temperature. Grain refinement efficiency and resulting thermal stability were evaluated after three passes with respect to utilization of various strain paths. Results were obtained using light microscopy and X-ray diffraction methods; Mechanical properties of extruded materials were also tested. Thermal stability was studied after application of three annealing cycles. Based on the findings, Bc route is the most efficient strain path with respect to the grain refinement; higher speed of extrusion (10 mm/s) corresponds with suppression of the static recrystallization. Measured strength, obtained after three passes (route A), achieved values around 440 MPa homogeneously along the cross section of the extruded material. Homogeneity of deformation was also confirmed by micro-hardness tests. The grain size, determined after three passes, averaged out 1.2 mu m. Application of TCAP (three passes) brought markedly homogeneous deformation throughout the processed sample in comparison with classical ECAP process.
10.1007-s10853-011-5805-0	-1		The homogeneous coarse-grained (CG) Cu-Ni alloys with nickel concentrations of 9, 26, 42, and 77 wt% were produced from as-cast ingots by homogenization at 850 A degrees C followed by quenching. The subsequent high-pressure torsion (5 torsions at 5 GPa) leads to the grain refinement (grain size about 100 nm) and to the decomposition of the supersaturated solid solution in the alloys containing 42 and 77 wt% Ni. The lattice spacing of the fine Cu-rich regions in the Cu-77 wt% Ni alloy was measured by the X-ray diffraction (XRD). They contain 28 +/- A 5 wt% Ni. The amount of the fine Ni-rich ferromagnetic regions in the paramagnetic Cu-42 wt% Ni alloy was estimated by comparing its magnetization with that of fully ferromagnetic Cu-77 wt% Ni alloy. According to the lever rule, these Ni-rich ferromagnetic regions contain about 88 wt% Ni. It means that the high-pressure torsion of the supersaturated Cu-Ni solid solutions produces phases which correspond to the equilibrium solubility limit at 200 +/- A 40 A degrees C (Cu-77 wt% Ni alloy) and 270 +/- A 20 A degrees C (Cu-42 wt% Ni alloy). To explain this phenomenon, the concept of the effective temperature proposed by Martin (Phys Rev B 30:1424, 1984) for the irradiation-driven decomposition of supersaturated solid solutions was employed. It follows from this concept that the deformation-driven decomposition of supersaturated Cu-Ni solid solutions proceeds at the mean effective temperature T (eff) = 235 +/- A 30 A degrees C. The elevated effective temperature for the high-pressure torsion-driven decomposition of a supersaturated solid solution has been observed for the first time. Previously, only the T (eff) equal to the room temperature was observed in the Al-Zn alloys.
10.1007-s10853-011-5919-4	4	transformation; martensite; martensitic; phase; shape; beta; memory; shape memory; temperature; temperatures; martensitic transformation; gamma; transformation temperatures; effect; thermal	It is known that the thermal effect (thermal inertia) in differential scanning calorimetry causes significant error of measuring the martensite finish temperature (Mf) in shape memory alloy, while the start temperature (Ms) is virtually unaffected. This article shows that the error can be avoided by accounting for the thermal effect quantitatively by mathematical modeling, if the kinetics of the martensitic transformation is properly prescribed. In common with two representative shape memory alloys, Cu-Al-Ni and Ni-Ti alloys, exponential decay is appropriate for expressing the kinetics. The model analysis is extended to the two methods of extrapolation which aims at excluding the thermal effect from DSC data. One is the extrapolation of the cooling rate to zero, and the other is that of the mass of sample to zero. It is shown that both extrapolations construct a temperature between the Ms and Mf. Typically, the temperature is below the Ms by one-third of the interval between the two temperatures.
10.1007-s10853-012-6375-5	11	glass; bulk; metallic; bulk metallic; gfa; bmg; glassy; metallic glass; ability; bulk metallic glass; amorphous; addition; crystallization; mm; glass-forming	Effects of a small amount addition of Cr on glass-forming ability (GFA) and mechanical properties of Cu-Zr-Al bulk metallic glass were investigated. The GFA of (Cu46Zr46Al8)(100-x) Cr (x) (x = 0, 0.25, 0.5, 0.75, and 1 at%) alloys tends to decrease with the increasing Cr content. A good correlation between the GFA and the temperature interval of supercooled liquid region Delta T (x) or parameter gamma exists in these alloys. Addition of an appropriate amount of Cr can significantly improve the plasticity of the alloys. The bulk metallic glass with x = 0.5 exhibits promising mechanical properties with high fracture strength of 1870 MPa and obvious plastic strain of 2.23%.
10.1007-s10853-012-6525-9	-1		The effect of alloying with 0.9 wt% hafnium on the thermal stability of the Cu-0.7%Cr alloy after severe plastic deformation by high pressure torsion has been studied by microhardness and resistivity measurements, optical microscopy, and transmission electron microscopy. The data obtained were used to construct the curves of the temperature dependences of microhardness and resistivity for the alloy samples in a temperature range of 50-550 A degrees C and the curves of the microhardness distribution over the sample diameter. The effect of preliminary heat treatment on the stability of the structure formed upon deformation is considered. It is shown that alloying with hafnium decreases the grain size from 250 to 120 nm, increases the strength, and elevates the temperature of the beginning of alloy softening upon heating. In addition, the introduction of hafnium to the alloy results in the occurrence of aging upon heating, and the strength reaches maximum (3177 MPa) at a temperature of 450 A degrees C.
10.1007-s10853-012-6587-8	6	grain; deformation; strain; strength; dislocation; cu-; tensile; size; ecap; grain size; sfe; ductility; hardening; high; stress	A copper alloy, Cu-0.1 %Zr, was subjected to severe plastic deformation at room temperature using quasi-constrained high-pressure torsion. Disks were strained through different numbers of revolutions up to a maximum of ten turns under an applied pressure of 6.0 GPa and then examined to evaluate the evolution in the Vickers microhardness, HV, and the microstructure. The results show lower values of HV in the center regions of the disks in the early stages of processing but a gradual evolution to a high degree of hardness homogeneity after five and ten turns. Under conditions of hardness homogeneity, the distributions of the grain boundary misorientations are essentially identical at the center and the periphery of the sample. Homogeneity was further confirmed by conducting tensile testing at elevated temperatures where similar stress-strain curves and similar elongations to failure were recorded after processing through five and ten turns of HPT.
10.1007-s10853-012-6731-5	-1		The thermal stability of nanocrystalline cartridge brass (Cu-30 at% Zn) and brass-Zr alloys were investigated. The alloys were produced by cryogenic ball milling and subsequently heat treated to a maximum temperature of 800 A degrees C. The grain size of pure brass was found to be relatively stable in comparison to pure copper, and a high hardness was retained up to 600 A degrees C. When 1 at% zirconium was alloyed with the brass, the grain size was stabilized near 100 nm even at 800 A degrees C. At the highest temperature, hardness was retained above 2.5 GPa for 1 and 5 at% zirconium alloys, but the pure brass softened significantly. The stabilization is believed to be dominated by Zn-Zr interactions as a second phase of these two was observed in X-ray diffraction and transmission electron microscopy. Thermodynamic modeling indicates a zero grain boundary energy may be achieved depending on the mixing enthalpy value used (i.e., calculated vs. experimental) under ideal conditions, but microstructural features such as twinning and second phase particles are thought to be the dominant stabilization mechanism. Zr worked well in stabilizing the brass in the nanocrystalline state to nearly 90 % of its melting temperature.
10.1007-s10853-012-6773-8	-1		The transition from incomplete to complete grain boundary (GB) wetting has been studied in the (Cu) + L region of the Cu-In phase diagram in the broad interval of In concentrations from 4 to 22 wt% In. The number of completely wetted GBs increases with increasing temperature and In content. With increasing amount of the melt the GBs with non-zero contact angle become apparently completely wetted. A geometrical model describing the influence of the amount of the liquid phase on the mean contact angle and the portion of completely wetted GBs has been developed. Using this model, the values of the temperatures of the start T (wmin) = 715 A degrees C and the end of the GB wetting transition T (wmax) = 986 A degrees C in the Cu-In system were determined.
10.1007-s10853-012-6946-5	11	glass; bulk; metallic; bulk metallic; gfa; bmg; glassy; metallic glass; ability; bulk metallic glass; amorphous; addition; crystallization; mm; glass-forming	Glass formation, structure and thermal properties of alloys in the binary Cu100-xHfx alloy system, where x = 25-50 at%, are reported and discussed. This work also presents a comparison between copper casting techniques, from thick melt-spun ribbons to suction cast cylindrical rods, and the prediction of critical diameter, d(c), based on maximum ribbon thickness, x(c). Ribbons of Cu60Hf40 and Cu65Hf35 exhibited a fully glassy phase up to a thickness of 170 mu m. Suction casting lead to an increase in the largest diameter over which both alloys could be cast, in comparison to melt-spun ribbons, and remain amorphous, with Cu65Hf35 showing a large critical diameter of 1 mm. This result is rationalised by a lower liquidus temperature, T-1, which maximises the reduced glass transition temperature, T-rg, and also correlates closely with the eutectic point. Finally, there were remarkable similarities between the Miedema model and the efficient packing model for predicting the range for metallic glass formation in this binary system.
10.1007-s10853-012-7072-0	6	grain; deformation; strain; strength; dislocation; cu-; tensile; size; ecap; grain size; sfe; ductility; hardening; high; stress	Experiments were conducted to evaluate the microstructures and mechanical properties of a Cu-0.1 % Zr alloy processed using two different techniques of severe plastic deformation: equal-channel angular pressing (ECAP) and high-pressure torsion (HPT). The samples were processed at room temperature through ECAP for eight passes or through HPT for 10 turns. The results show HPT is more effective both in refining the grains and in producing a large fraction of grain boundaries having high angles of misorientation. Both procedures produce reasonably homogeneous hardness distributions but the average hardness values were higher after HPT. In tensile testing at 673 K, the highest strength and ductility was achieved after processing by HPT. This is attributed to the grain stability and high fraction of high-angle grain boundaries produced in HPT.
10.1007-s10853-013-7153-8	-1		A Cu-11.8 wt% Al alloy was quenched in iced water from a high temperature (850 A degrees C) to introduce a martensitic phase and then the alloy was processed using quasi-constrained high-pressure torsion (HPT). The micro-hardness and the microstructures of the unprocessed and severely deformed materials were investigated using a wide range of experimental techniques (X-ray diffraction, optical microscopy, scanning electron microscopy, transmission electron microscopy, and high- resolution TEM). During HPT, a stress-induced martensite-martensite transformation occurs and an martensite phase is formed. In the deformed material, there are nanoscale deformation bands having high densities of defects and twins in the martensite. It was observed that a high density of dislocations became pinned and accumulated in the vicinity of twin boundaries, thereby demonstrating a strong interaction between twin boundaries and dislocations during the HPT process.
10.1007-s10853-013-7155-6	-1		Ultrafine-grained and even nanostructured materials can be fabricated using severe plastic deformation to ultra-high strains in equal-channel angular pressing (ECAP), high-pressure torsion (HPT), machining and their combinations, such as machining of ECAP specimens, HPT of ECAP billets and HPT of machining chips. This report presents recent results of investigations of the microstructures and microtextures of pure copper, nickel and aluminium subjected to different deformation processes to ultimately high imposed strains. A comparison of the microstructure, dislocation density and microhardness developed during combinations of different strain paths is performed. All characteristics were analysed by X-ray, transmission and scanning electron microscopy, and electron backscatter diffraction (EBSD). The influence of different processing routes is discussed in terms of the accumulated strain and microstructure refinement. The saturation in grain refinement is examined with reference to the recovery taking place during ultra-high strain deformation. A phenomenological model based on the Voce equation is applied for fitting parameters based on the experimental data and this is suggested for a prediction of microhardness evolution for pure metals (Ag, Au) and Cu-based (Zn, Al) alloys.
10.1007-s10853-013-7231-y	6	grain; deformation; strain; strength; dislocation; cu-; tensile; size; ecap; grain size; sfe; ductility; hardening; high; stress	The microstructure and crystallographic texture have been investigated in a Cu-45 at%Ni alloy after heavy rolling and subsequent annealing at different temperatures. Cold-rolling to a von Mises strain of 5.7 produced a sample with an average boundary spacing along the normal direction of similar to 70 nm and a large fraction of high-angle boundaries (HABs), similar to 70 %. Annealing of this sample for 1 h at temperatures a parts per thousand currency sign450 A degrees C causes structural coarsening, during which the fraction of HABs decreases. Annealing at higher temperatures results in pronounced discontinuous recrystallization accompanied by twinning. Large frequencies of twin boundaries contribute to high HAB fractions measured in the as-recrystallized condition. Cube-oriented grains demonstrate a size advantage compared to grains of other orientations, thus creating a strong cube texture in the recrystallized material. Further annealing of the recrystallized microstructure promotes grain growth, which leads to a significant strengthening of the cube texture and to a dramatic loss of HABs. After 1 h of annealing at 1000 A degrees C the fraction of the cube texture reaches 99 % and the HAB fraction is 12 %.
10.1007-s10853-013-7262-4	-1		Structure of Cu-Sb melts has been studied by ab initio molecular dynamics simulations, high-temperature X-ray diffraction and resistivity measurements. Over the whole concentration range, heterogeneous coordination numbers are larger than that of homogeneous atoms. This indicates preferential Cu-Sb coordination in Cu-Sb melts. A drop is observed in maximum position of simulated Sb-Sb partial distribution functions around Cu75Sb25, which reveals the rapid increase of Sb-Sb coordination. Around eutectic melts, main peak splitting is observed in both structure factor and simulated total pair distribution functions, which reveals the co-existence of Cu-Sb heterogeneous and Sb-Sb clusters. Abnormal changes in temperature coefficient of resistivity are observed around pure Sb and in compound-forming range, which are well interpreted as reinforcement of Peierls distortion and Cu3Sb compound clusters, respectively. Structural inhomogeneity that results from atomic size effect also has been discussed by analyzing concentration dependence of Warren-Cowley parameters and concentration correlation functions.
10.1007-s10853-013-7751-5	4	transformation; martensite; martensitic; phase; shape; beta; memory; shape memory; temperature; temperatures; martensitic transformation; gamma; transformation temperatures; effect; thermal	The high reversibility of the martensitic transformation occurring in shape-memory alloys (SMAs) is at the origin of the mechanical performance of these materials. Infrared thermography is employed in this study to measure the mechanical dissipation produced by Cu-Zn-Al SMA specimens during stress-induced phase transformation. In practice, temperature change is first measured on the surface of a specimen subjected to cyclic mechanical loading at constant ambient temperature. The heat produced by the material can then be deduced from the temperature change by using the heat diffusion equation. The heat associated to mechanical irreversibility is expected to be very low compared to the other heat quantities produced by the material (such as the latent heat due to phase change and the heat due to thermoelastic coupling), so measuring this quantity requires special attention, as emphasized in this paper. The procedure which enables us to extract the mechanical dissipation from the measured heat source is first presented. The technique is then applied to two types of specimens: martensitic and austenitic. Different values of mechanical dissipation were measured, thus revealing different levels of mechanical irreversibility.
10.1007-s10853-014-8058-x	-1		The reflectivity of some noble metals alloyed with copper of the formula Cu (x) M1-x , where M is gold, platinum, palladium and silver, has been modelled using only the available optical constants of the pure parent metals, copper, gold, platinum, palladium and silver. The results are compared with experimentally determined reflectivity for some of these alloys and shown to give reasonable approximations, suggesting that the method has utility for the estimation of the reflectivity of alloys when no experimental data are available. The method of estimation of reflectivity has been extended to include two-phase alloys as well as homogenous alloys.
10.1007-s10853-014-8258-4	-1		Pure copper (Cu) having bimodal 'harmonic structure' (HS) was fabricated by a technique based on severe plastic deformation of powders, which involved tailored mechanical milling and spark plasma sintering. The harmonic-structured Cu demonstrates a unique combination of high strength and large elongation superior to its homogeneous as well as bimodal heterogeneous counterparts. Specific features of harmonic structure, i.e. continuous network of ultra-fine grained (UFG) regions encompassing coarse-grained areas, lead to the extension of uniform elongation. The optimum combination of properties in pure Cu is found to be in the harmonic-structured material having 40 % UFG fraction.
10.1007-s10853-014-8299-8	-1		A single-phase Cu-Al alloy with a low stacking fault energy was processed by cold rolling and subsequent annealing. Fully recrystallized microstructures composed of ultrafine grains were obtained after isothermal annealing at different temperatures. The minimum mean grain sizes achieved were below 1 mu m. It was found that the microstructures were homogeneous after annealing at 400 A degrees C, but somehow inhomogeneous after annealing at lower temperature of 300 A degrees C and higher temperature of 550 A degrees C. Superior strength and ductility were obtained by controlling the grain size of the microstructures. After annealing at 400 A degrees C for 10 s, a fully and homogeneously recrystallized material with mean grain size of 770 nm was produced, which had a high yield strength of 524.2 MPa and a remarkable uniform elongation of 15.7 %.
10.1007-s10853-014-8329-6	-1		The occurrence of discontinuous reactions under isothermal annealing of melt-spun Cu-10 at. % Co alloys, consisting of ribbons (20 A mu m thick) with columnar grains in the as-solidified state, has been investigated. The microstructure of the ribbons for different annealing temperatures (723-923 K) and annealing times (5-60 min) was determined by transmission electron microscopy, including analysis by energy-dispersive X-ray spectroscopy. Magnetic properties at room temperature were measured by means of hysteresis curve measurements in a vibrating sample magnetometer. Different types of microstructure were observed within grains and at grain boundaries. The spinodal decomposition microstructure was observed during the early stages of annealing for all annealing temperatures. Spherical precipitates grew from the modulated structure at a later stage, forming homogenous distributions throughout the grains. Heterogeneous distributions of incoherent precipitates formed at T > 873 K. As result of discontinuous precipitation, all grain boundaries exhibited arrays of rod-like Co precipitates with diameters and inter-rod spacing of few nanometers. The coarsening of discontinuous precipitates is attributed to a grain boundary-controlled phenomenon, called discontinuous coarsening (DC). The columnar morphology of the grains in the as-solidified alloy was connected with Co rods that were primarily oriented along the ribbon plane. This structure is connected with magnetic anisotropy, which is later weakened by DC. These results elucidate the unusual magnetic behavior of melt-spun Cu-Co alloys and provide a key to understanding their higher magnetoresistance in comparison with other heterogeneous systems.
10.1007-s10853-014-8339-4	6	grain; deformation; strain; strength; dislocation; cu-; tensile; size; ecap; grain size; sfe; ductility; hardening; high; stress	Quenched and slowly cooled (annealed) Cu-0.7 %Cr, Cu-0.9 %Hf, and Cu-0.7 %Cr-0.9 %Hf alloys were processed by high pressure torsion (HPT). The microstructures of the alloys were studied immediately after HPT and subsequent annealing. It has been shown that the microhardness and the thermal stability of the severely deformed microstructure increase, while the average grain size decreases in the order of Cu-0.7 %Cr, Cu-0.9 %Hf, and Cu-0.7 %Cr-0.9 %Hf alloys. The microhardness in all alloys is higher after quenching and HPT, than after annealing and HPT. The largest dislocation density is achieved by quenching and HPT in Hf-containing samples. Cu5Hf phase precipitations in Hf-containing alloys are more effective in retarding grain growth in comparison with Cr particles and lead to additional hardening during aging. It has been demonstrated that HPT-processing with subsequent heat-treatment might yield the combination of large hardness and high electrical conductivity in Cu alloys.
10.1007-s10853-014-8475-x	-1		The wetting of angular alumina particle preforms by Cu-Sn alloys is investigated by means of pressure infiltration experiments conducted at 1150 A degrees C, using a system enabling dynamic and precise measurements of the metal volume injected into the preform. Wetting is quantified in terms of drainage curves, which plot the volume fraction of molten metal in the packed powder preform (also called saturation) versus the applied pressure. The shape of the curves confirms earlier findings, namely (i) the initial stage of infiltration is dominated by percolation and obeys a universal scaling relation while the metal shape is fractal; and (ii) at higher saturation, incremental pore-filling is dictated by local pore geometrical characteristics, saturation curves obeying then the Brooks-Corey correlation. According to sessile drop data in the literature, the Cu-Sn system is characterized by relatively small changes in the contact angle with alloy composition (128A degrees-122A degrees), while the metal surface tension changes by more than a factor two over the whole composition range. One would, therefore, expect that the drainage curves be indifferently proportional to the molten metal surface tension or the work of immersion: the present data show that this is indeed verified.
10.1007-s10853-014-8598-0	-1		This research experimentally investigated how the solid fraction level of an array of projecting nickel cylindrical microstructures influenced the electrodeposition of Cu-Ni alloy on the cylindrical microstructures. The electrodeposition of Cu-Ni alloy on a substrate with an array of projecting cylindrical structures resulted in the concentrated precipitation of Cu ions at the top of the cylinders. Relatively more electrodeposited structures were formed at the top surface of the cylinders than at the bottom surface, and electrodeposited structures were not formed at the bottom surface of the substrate when the solid fraction was increased. Structures at the edges of the cylinders' top surfaces grew larger than the structures at the centers of the surfaces. The heights of the electrodeposited structures decreased as the solid fraction increased. In addition, shadow bands with no electrodeposited structures were observed at the bottom surface of the substrate a certain distance away from the cylinders.
10.1007-s10853-014-8713-2	6	grain; deformation; strain; strength; dislocation; cu-; tensile; size; ecap; grain size; sfe; ductility; hardening; high; stress	A coarse-grained Cu-36Zn-2Pb alloy with an initial grain size of 54 mu m was processed by high-pressure torsion (HPT) at room temperature under an applied pressure of 6.0 GPa through 1-10 turns, and the evolution of microstructure and microhardness was investigated. Analysis by X-ray diffraction (XRD) showed that in HPT processing the beta'-phase transforms to an alpha-phase and a {111} texture is formed. Microscopic examination showed that dislocations were first formed at equivalent strains of not more than 25 and when the equivalent strain increased to 40 there was evidence for twins and secondary twinning. Fine grains were formed with an increase in equivalent strain to 100 and with further straining these refined grains acted as precursors for additional grain refinement. The refined equiaxed grain size was 250 nm after HPT through an equivalent strain of 100 and the results show the microhardness reached a saturation value of 220 HV.
10.1007-s10853-015-8956-6	4	transformation; martensite; martensitic; phase; shape; beta; memory; shape memory; temperature; temperatures; martensitic transformation; gamma; transformation temperatures; effect; thermal	A study of the grain growth kinetics in two shape memory alloys, CuAlBe and CuZnAl, is reported. Isothermal aging treatments at temperatures between 1023 and 1123 K were conducted, determining the grain size distribution as a function of time. The results show that the size distribution can be described by a log-normal type relationship, and is time-invariant. It was found that the arithmetic mean grain size almost coincide with the mode, which means that it is a representative parameter of the microstructure along the annealing time. The growth kinetics is strongly dependent on the aging temperature in CuZnAl, while is weakly in CuAlBe. It was verified that the grain size-time power law usually applied is not appropriate to describe the process, and an early departure from the ideal behavior is observed. The modification with a time-dependent dragging force gives a reasonable approximation to the grain growth kinetic. The obtained results are compared with the scarce data existing on this type of alloys.
10.1007-s10853-015-9278-4	12	thermodynamic; ternary; phase; data; experimental; equilibria; phase equilibria; liquid; binary; experimental data; calculated; phases; literature; model; calphad	Phase equilibria in the Cu-Ni-Zr ternary system have been measured through alloy sampling combined with diffusion couple approach . According to the phase relations identified with electron probe microanalysis and X-ray diffraction techniques, isothermal sections at both 1073 and 1293 K were constructed. It is evident that remarkable ternary solubility occurs in almost all binary intermetallic phases at both temperatures. The formerly reported ternary compounds T1 (Cu20-40Ni40-60Zr20) and T2 (Cu20-25Ni60-65Zr15) were not verified in this work. No other ternary compound was detected. In addition, continuous dissolution between Cu10Zr7 and Ni10Zr7 at 1073 K was observed.
10.1007-s10853-015-9306-4	4	transformation; martensite; martensitic; phase; shape; beta; memory; shape memory; temperature; temperatures; martensitic transformation; gamma; transformation temperatures; effect; thermal	Prior studies on shape memory alloys have identified size effects on the superelastic, i.e., stress-induced, hysteresis of martensitic transformations. However, literature on thermally induced transformations and size effects upon stored elastic energy is rather limited. In this work, a complementary sample size effect on the stored elastic energy of the transformation, and its effect on variant selection, is elaborated. Shape memory alloy microwires of a CuAlMnNi alloy are drawn with diameters varying between 45 and 255 mu m and processed to obtain bamboo grain structures, where the grain boundaries lay almost perpendicular to the wire axis. Calorimetric and thermomechanical analyses of the microwires establish a decreasing contribution of stored elastic energy to the free energy of martensitic transformation as the wire diameter is reduced. This in turn affects the transformation ranges and macroscopic strain generated in constrained thermal cycling. The effect is shown to be associated with a decrease in number of interacting martensite variants as well as relaxation on free surfaces. The presented results indicate that thermal actuation of lightly biased SMA wires is enhanced in finer wires.
10.1007-s10853-015-9354-9	-1		Mechanical strength and electrical conductivity are the most important properties of conducting metallic materials used in electrical engineering. Today, there is a growing need in this field for innovative conductor materials with improved properties. Meanwhile, the main issue is that high electrical conductivity and high strength are usually mutually exclusive due to physical nature of these properties. Alloying of pure metals results in significant increase of their mechanical strength, whereas electrical conductivity dramatically drops due to the scattering of electrons at solutes and precipitates. Recent studies have shown that intelligent nanostructural design in Al, Cu, and their alloys can improve combination of high mechanical strength with enhanced electrical conductivity. It was demonstrated that mechanical strength and electrical conductivity of these materials are primarily controlled by their microstructure, of which grain size, morphology of second phases, and their distribution, as well as dislocation structure, are the most important parameters. Rapid development of the state-of-the-art methods for the microstructural characterization at nano- and atomic scale has allowed a deeper insight into microstructure-properties relationship. The approach of intelligent nanostructural design of Al and Cu alloys has even enabled to increase the material strength with simultaneous improvement of its electrical conductivity. In this case, recent works on nanostructuring alloys by severe plastic deformation are of special interest, which gives rise to fundamental questions dealing with new mechanisms of strength and electrical conductivity as well as innovation potential of practical application of nanostructured materials. These issues are considered and discussed in the present progress article.
10.1007-s10853-015-9391-4	-1		After reviewing the initiation and growth models for discontinuous precipitation (DP) in metallic systems, this mode of transformation is examined in melt-spun supersaturated Cu-10 at%Co. Detailed observations of the micro and nanostructures developed by DP and coarsening upon isothermal aging treatments at temperatures ranging from 450 to 650 A degrees C are presented and discussed. Transmission electron microscopy has been extensively used in the characterization of precipitation phenomena. The analysis led us to propose a model for initiation and growth of DP and further coarsening in this alloy system. It is shown that, as precursor of DP, the onset of grain boundary migration is assisted by capillary forces and leaves a precipitate-free solute-depleted zone. Upon extended aging, discontinuous precipitation takes place as colonies of regularly spaced Co rod-like precipitates embedded in the depleted matrix. Discontinuous coarsening takes place generating arrays of coarser and wider-spaced precipitate colonies. Grain boundary curvature suggests that the transition from discontinuous precipitation to coarsening is related to the exhaustion of capillary, since in the latter, grain boundary migration occurs in the direction opposite to its center of curvature.
10.1007-s10853-016-0331-8	6	grain; deformation; strain; strength; dislocation; cu-; tensile; size; ecap; grain size; sfe; ductility; hardening; high; stress	The ultrafine-grained microstructures and functional properties, including wear resistance for dry sliding and electrical conductivity, were investigated in a Cu-0.3 %Cr-0.5 %Zr alloy processed by equal-channel angular pressing (ECAP) at a temperature of 400 A degrees C to total strains of 1, 2, and 4. Severe plastic deformation by ECAP to a total strain of similar to 1 led to a significant decrease in the wear resistance because of the rapid surface damage to both solution-treated (ST) and aged (AT) samples where a high density of dislocations was arranged in stochastic low-angle subboundaries by brittle fracture. Further deformation by subsequent ECAP passes promoted the subdivision of the shear bands by geometrically necessary boundaries. Correspondingly, the number of fine crystallites outlined by high-angle boundaries increased, and the wear rate decreased. After four ECAP passes, the wear rate decreased to the level of the initial state of the alloy and equaled 1.68 x 10(-5) mm(3)/(N m) and 1.40 x 10(-5) mm(3)/(N m) for ST and AT samples, respectively. The results demonstrate that the damage mechanism is the controlling factor for wear resistance of Cu-Cr-Zr bronze hardened by intense plastic straining.
10.1007-s10853-016-0526-z	-1		The atomic configurations and electronic structures of iron on Cu Sigma 5 symmetrical tilt grain boundary (GB) have been studied based on the density functional theory. Different segregation positions of iron are considered. A weak tendency of iron segregating to GB is arrived due to the segregation energy. In addition, iron segregation shows a cohesion strengthening effect of Cu GB according to Rice-Wang model, which is mainly contributed by the charge redistribution. Finally, an enhancement of the local magnetic moment of iron in Cu GB or bulk or surface is explored due to larger atomic volume than the FCC iron crystal and the Cu atoms surrounding iron are slightly polarized by the doped iron. This study can enrich the understanding of the effects of iron on the cohesion of CuFe alloy and also might supply an indirect guidance to expand the application of Cu-Fe alloy in electronic device manufacture field.
10.1007-s10853-016-0700-3	7	irradiation; shear; grain; ta; deformation; size; radiation; voids; nanocrystalline; simulations; similar; void; temperature; irradiated; boundaries	Hybrid Monte Carlo/molecular dynamics (MD) simulations are conducted to study the microstructures of nanocrystalline (nc) Cu/Ag alloys with various Ag concentrations. When the Ag concentration is below 50 Ag atoms/nm(2), an increase in Ag concentration leads to a gradual growth of monolayer grain boundary (GB) complexions into nanolayer complexions. Above the concentration of 50 Ag atoms/nm(2), wetting layers with a bulk crystalline phase are observed. The effects of Ag on mechanical properties and deformation mechanisms of nc Cu/Ag alloys are investigated in MD simulations of uniaxial tension. GB sliding resistance is found to first increase and then decrease with an increase in Ag concentration. Surprisingly, we also find that the dislocation density decreases monotonically with an increase in Ag concentration, which suggests that the grain interiors are softened by the introduction of Ag dopants at GBs. In addition, there is a critical Ag concentration that maximizes flow stress of nc Cu/Ag alloys. The flow stress, GB sliding resistance, and the intragranular dislocation densities become less sensitive to Ag dopants when the grain diameter increases from 5 to 40 nm.
10.1007-s10853-016-9854-2	6	grain; deformation; strain; strength; dislocation; cu-; tensile; size; ecap; grain size; sfe; ductility; hardening; high; stress	Equal channel angular pressing (ECAP) results in grain refinement of the Cu-0.7 % Cr alloy with an average grain size of 320 +/- A 73 nm. Addition of hafnium leads to a further decrease of average grain size down to 225 +/- A 82 nm and to an increase of the fraction of high angle boundaries from 40 to 53 %. The microhardness of the Cu-0.7 % Cr-0.9 % Hf alloy is higher than that of the Cu-0.7 % Cr alloy in the quenched state, after ECAP followed by annealing in the temperature interval of 400-550 A degrees C during which aging occurs. Compared with the quenched state, ECAP increases the tensile strength of the Cu-0.7 % Cr and Cu-0.7 % Cr-0.9 % Hf alloy by a factor of 2.3 and 2.2, respectively. Aging leads to additional strengthening. Compared with the Cu-0.7 % Cr alloy, the strength of the Cu-0.7 % Cr-0.9 % Hf alloy after ECAP and after subsequent aging is 1.3 and 1.5 times higher, respectively.
10.1007-s10853-017-0827-x	1	shape; memory; shape memory; damping; martensite; martensitic; damping capacity; transformation; capacity; strain; superelasticity; temperature; cu-al-mn; shape memory effect; effect	In this study, the Cr was added into Cu-Al-Mn alloys for replacing Cu and Mn, and the microstructure, martensitic transformation, stress-strain behavior, superelasticity and shape memory effect of quaternary Cu-Al-Mn-Cr shape memory alloys were investigated. All the studied alloys exhibit a mixed microstructure consisted of dominant L2(1) parent, small amounts of A2(Cr) and 2H(gamma(1)') martensite, as well as a reversible martensitic transformation. Although the alloys are main L2(1) parent before deformation, partial stress-induced 2H(gamma(1)') martensite can be stabilized and retained after unloading. Therefore, the same alloy under a certain deformation temperature not only exhibits superelasticity property during deformation, but also the deformed alloy also shows shape memory effect when heated. The results further show that Cu-12.8Al-7.5Mn-2.5Cr alloy has a good superelasticity strain of 2.9% as well as a shape memory effect of 1.5%. Cu-12.7Al-6.9Mn-1.8Cr alloy possesses much the best superelasticity strain close to 5.0% under a pre-deformation of 10% and a shape memory effect of 2.0%. The best shape memory effect up to 2.5% with 10% of pre-deformation and a superelasticity strain of 2.8% are obtained in Cu-12.5Al-5.8Mn-4.1Cr alloy.
10.1007-s10853-017-0979-8	6	grain; deformation; strain; strength; dislocation; cu-; tensile; size; ecap; grain size; sfe; ductility; hardening; high; stress	The deformation behaviour of metals and alloys is significantly affected by both stacking-fault energy and processing temperature. By lowering the former, deformation twinning is favoured over dislocation slip, whilst cryogenic processing partially suppresses dynamic recovery. Three materials having different stacking-fault energies, that is, Al AA1050 (high), pure Cu (medium) and Cu-15Zn alloy (low) were rolled at room (RTR) and at cryogenic (CR) temperatures up to a true strain equal to 1.5. Annealed coarse-grained samples were tested in tension at room and cryogenic temperatures. The processed samples were characterized by optical and transmission electron microscopy, hardness measurements and room-temperature tensile tests. CR increases the tensile strength with respect to RTR for the three materials; elongation to failure is decreased for AA1050, whilst for Cu and Cu-15Zn the CR effectively increases the ductility. Cu-15Zn sample after CR exhibits a microstructure relatively heterogeneous, suggesting static recrystallization events in the temperature excursion from 77 to 298 K. Finally, it was concluded that cryogenic deformation increases strength, whilst low SFE increases the ability to absorb plastic deformation, an effect strongly increased at cryogenic temperatures. The present investigation gives some basis for the development of cryogenic severe plastic deformation processes.
10.1007-s10853-017-1307-z	-1		Surface oxidation is frequently encountered in powder metallurgy of metals and alloys, and it leads to a reduction in their electrical conductivities. Therefore, it is highly desired to remove the naturally occurring oxide layer from the particles surface and to prevent its subsequent formation. A new approach was proposed in this study, where copper particles were mixed with graphene oxide (GO) sheets in an aqueous solution containing dopamine (DA) molecules. It was expected that polymerization of the DA molecules on the surface of the copper particle could promote both a reduction of surface oxide layer and the adhesion of GO sheets to the particles surface. The powder system was then washed, heattreated in inert atmosphere and compressed at room temperature to form compacts. Electron microscopy revealed nearly ideal dispersion of GO sheets within the copper matrix. X-ray photoelectron spectroscopy showed a shift from Cu2+ to Cu+ and metallic copper in the coated and heat-treated samples, and Raman spectroscopy pointed to the increased amount of sp(2) carbon as a result of the heat treatment. All DA/GO-coated and heat-treated compacts exhibited significantly higher electrical conductivity than those that have been made from pure copper powder or were not been heat-treated. Also, indentation measurements showed an increase in microhardness in samples with the shortest, 10 min, coating time and heat-treated at the highest, 600 degrees C, temperature.
10.1007-s10853-017-1666-5	-1		The shock response of Cu (x) Zr100-x (x = 30, 50 and 70) metallic glasses (MGs) is characterized using large-scale molecular dynamics simulations. A wide range of piston velocities U (p) = 0.125-2.5 km/s are simulated corresponding to shock pressures from 3 to 130 GPa. Independent of composition, the metallic glasses exhibit the following shock wave propagation regimes: (1) single elastic shock wave for U (p) < 0.25 km/s, (2) split elastic and plastic shock waves for 0.25 < U (p) < 0.75 km/s and (3) overdriven plastic shock wave with a narrow elastic precursor for U (p) > 0.75 km/s. Within the split wave and overdriven regimes, the amplitude of the elastic precursor increases with increasing shock intensity, thereby indicating a pressure-dependent yield criterion. Hugoniot states are strongly dependent on the Cu content of the MG with Cu70Zr30 exhibiting a much higher resistance to plastic deformation than either Cu50Zr50 or Cu30Zr70.
10.1007-s10853-017-1706-1	7	irradiation; shear; grain; ta; deformation; size; radiation; voids; nanocrystalline; simulations; similar; void; temperature; irradiated; boundaries	There has recently been a great deal of interest in employing immiscible solutes to stabilize nanocrystalline microstructures. Existing modeling efforts largely rely on mesoscale Monte Carlo approaches that employ a simplified model of the microstructure and result in highly homogeneous segregation to grain boundaries. However, there is ample evidence from experimental and modeling studies that demonstrates segregation to grain boundaries is highly non-uniform and sensitive to boundary character. This work employs a realistic nanocrystalline microstructure with experimentally relevant global solute concentrations to illustrate inhomogeneous boundary segregation. Experiments quantifying segregation in thin films are reported that corroborate the prediction that grain boundary segregation is highly inhomogeneous. In addition to grain boundary structure modifying the degree of segregation, the existence of a phase transformation between low and high solute content grain boundaries is predicted. In order to conduct this study, new embedded atom method interatomic potentials are developed for Pt, Au, and the PtAu binary alloy.
10.1007-s10853-017-1952-2	-1		Ultrafine-grained Cu-5 vol%Al2O3 nanocomposite rods were fabricated by a combination of high-energy mechanical milling of Cu and Al2O3 powders and powder compact extrusion at 300, 500, 700 and 900 degrees C. The extruded rods were investigated to evaluate microstructures, mechanical properties, fracture behavior and electrical resistivity. It was found that the extrusion temperature has a pronounced effect on Cu grain growth, Al2O3 particle coarsening and particle distribution. High-temperature extrusion leads to directional coarsening of certain grains. As such, a heterogeneous matrix structure of large elongated and equiaxed grains is created, and this unique matrix structure brings beneficial effects in tensile ductility and electrical resistivity. While Al2O3 dispersions in the matrix improve the overall performance of the nanocomposite, an incorrect selection of the extrusion temperature may have detrimental effects on yield strength and resistivity. Tensile fractography investigation shows that the presence of Al2O3 results in failures along grain boundaries. This study also provides a framework for modeling the mechanical and electrical properties of such complex matrix structures. Modeling tools/formulae can be used to predict mechanical/electrical properties via microscopic characteristics and hence can also be used to understand the effect of processing variables.
10.1007-s10853-018-2638-0	16	wear; composite; composites; powders; milling; particles; powder; wt; sliding; friction; hardness; matrix; mechanical; surface; properties	In the present work, hot press of Cu-15 wt% Al alloys was carried out in a vacuum environment at a sintering temperature of 500 degrees C for 30 min with varying pressure (100-500 MPa) to densify the alloys. Both the density and hardness of Cu alloys were significantly increased with increasing the hot press pressure. A maximum density of similar to 94.5% rho th (theoretical density) and micro-hardness of similar to 6.2 GPa was achieved for Cu-Al alloy after hot press at 500 degrees C with 500 MPa pressure application. The XRD, SEM-EDS analysis confirms the presence of solid solution alpha (Cu0.78Al0.22) and gamma (Cu9Al4) inermetallic phases in the sintered samples. Maximum hardness of 7.88 GPa and elastic modulus of 177.35 GPa was measured for Cu-Al alloy using nano-indentation test. It must be noted that so far in the literature a maximum hardness of 4.9 GPa was reported for Cu-based materials. The alloy was also measured with a moderately high compressive yield strength (1019 MPa), compressive strength (1106 MPa), and a reasonable amount of strain (6.6%). The wear tests revealed that the Cu-15 Al alloy hot pressed at 500 MPa pressure can exhibit better wear properties. Low coefficient of friction (COF) of 0.15 and wear rate of 0.71 x 10(-5) mm(3)/N-m was observed at a sliding speed of 0.25 m/s and high COF of 0.20 and wear rate of 4.33 x 10(-5) mm(3)/N-m were noted with further increasing the sliding speed (1.25 m/s). Further microstructural characterization of worn surfaces reveals abrasion wear as the major dominant wear mechanism. The present work clearly demonstrates the use of a high amount of hot press pressure in achieving good sinter density for Cu-15 wt% Al alloys with superior hardness, better wear and compressive strength properties.
10.1007-s10853-018-2744-z	-1		Cu-Sn alloy was put in the high-temperature hot compression test with a strain rate of 0.01 s(-1) and distortion temperature of 550-700 A degrees C. Electron backscattered diffraction technology was adopted to analyze the distortion and microstructure features of different parts of the alloy. The results indicate that: As the temperature rises, the distribution frequency of the I 3 pound (n) (n = 1, 2, 3) grain boundary increases to 41.9% from 6.8% but drops suddenly at 650 A degrees C, which is similar to the frequency distribution changes in recrystallization and twin crystals. Meanwhile, multiple annealing twin crystals are generated and connected to form grain clusters with I 3 pound (n) orientation among each other. In the inverse pole figure, with the recrystallization continuing, the polar densities of the fiber textures of varied orientations in T1, T2, T3, T4 and other areas decreased gradually; in tensile test of Cu-Sn Alloy, yield strength and tensile strength at break decrease slowly.
10.1007-s10853-018-2922-z	-1		In spite of its huge technical significance, there does not seem to be consensus about how to model the precipitation contribution to the creep strength . Most contributions in the literature are based on a constant internal stress (also called back stress or threshold stress) from the precipitation. It is well-known and it will also be demonstrated in the paper that this assumption is at variance with observations except for some ODS alloys. There is, however, one model developed by Eliasson et al (Key Eng Mater 171-174:277-284, 2000) that seems to be able to represent experimental data without the use of any adjustable parameters. It has successfully been applied to describe the creep strength of austenitic stainless steels. Due to the fact that various mechanisms contribute to the creep strength in these steels, the model has not been fully verified. The purpose of this paper is to apply the model to published creep data for Cu-Co alloys, where the precipitation totally dominates the strength contribution to validate the model. In the paper, it is demonstrated that the model can indeed describe the influence of applied stress, alloy composition and heat treatment for the three analysed Cu-Co alloys.
10.1007-s10853-018-3139-x	-1		Grain boundary engineering via dopant segregation can dramatically change the properties of a material. For metallic systems, most current studies concerning interfacial segregation and subsequent transitions of grain boundary structure are limited to binary alloys, yet many important alloy systems contain more than one type of dopant. In this work, hybrid Monte Carlo/molecular dynamics simulations are performed to investigate the behavior of dopants at interfaces in two model ternary alloy systems: Cu-Zr-Ag and Al-Zr-Cu. Trends in boundary segregation are studied, as well as the propensity for the grain boundary structure to become disordered at high temperature and doping concentration. For Al-Zr-Cu, we find that the two solutes prefer to occupy different sites at the grain boundary, leading to a synergistic doping effect. Alternatively, for Cu-Zr-Ag, there is site competition because the preferred segregation sites are the same. Finally, we find that thicker amorphous intergranular films can be formed in ternary systems by controlling the concentration ratio of different solute elements.
10.1007-s10853-019-03592-8	1	shape; memory; shape memory; damping; martensite; martensitic; damping capacity; transformation; capacity; strain; superelasticity; temperature; cu-al-mn; shape memory effect; effect	The elastocaloric effect in Cu-Al-Mn shape memory alloy microwires fabricated by Taylor-Ulitovsky method was investigated. The microwires with bamboo-like grain architecture, homogeneous composition and favorable orientation were successfully prepared through high-temperature annealing heat treatment. The formation of the bamboo grains and high specific surface area contribute to the reduced martensite transformation hysteresis. A large recoverable strain up to 8.8% was achieved by two-way shape memory cycling under a low stress of 50MPa. Consequently, the microwire exhibited a large entropy change S-iso=16.1Jkg(-1)K(-1). Furthermore, the refrigeration capacity (RC) reached similar to 502Jkg(-1) over a working temperature interval T-FWHM=31K during direct transformation under 50MPa uniaxial stress. Finally, a reversible adiabatic temperature change T-ad=3.9K under a stress of 150MPa was obtained. This proves that the present Cu-Al-Mn microwire, with bamboo grains, high refrigeration property and low cost, may act as promising candidate materials for elastocaloric cooling.
10.1007-s10853-019-03647-w	-1		In this paper, the dynamic behavior of copper and aluminum alloys as used in electric drive units is investigated. Isothermal frequency sweeps are performed from 0.1 up to 50Hz at temperatures of up to 400 degrees C. An evaluation of the test results at a constant frequency of 1Hz shows a decrease in the storage modulus and an increase in the material damping. Considering all frequencies, a supplementary frequency dependency related to the material composition is detected. The lower the volume fraction of the alloying elements, the higher the impact of temperature and frequency on the material properties. The variations of the material parameters allow applying the time temperature superposition principle to estimate the dynamic behavior beyond the limited tested frequency range and temperatures by fitting the Williams-Landel-Ferry equation. Additional thermal aging of CU-ETP specimens does not affect the storage modulus, but diminishes the material damping. The findings show that each material has to be tested with regard to its respective application, material composition and manufacturing process. Furthermore, they demonstrate the relevance of considering the frequency-dependent material properties of low-alloyed copper and aluminum, especially in case of temperatures above 100 degrees C.
10.1007-s10853-019-03890-1	13	clusters; atomic; glass; atoms; composition; dynamics; metallic; icosahedral; glasses; simulations; molecular; cu-zr; molecular dynamics; metallic glasses; structural	The issue, high glass-forming abilities (GFAs) in solute-absent multicomponent metallic glasses (MGs), has been investigated by systematic experimental measurements coupled with theoretical calculations in the Cu34Zr14Ti36Pd16 quaternary alloy. It is found that the synergetic contribution of some atomic- and cluster-level structural features leads to the high GFA in this quaternary composition. At the atomic scale, Pd and Ti addition decreases the size gaps between Cu and Zr atoms, and increases the atomic packing efficiency; at the cluster scale, there are more icosahedral or icosahedral-like local structures, and the cluster regularity is enhanced because of the optimization of both topological and chemical distributions in clusters. The present work provides an in-depth understanding of GFAs in multicomponent alloys, and will shed light on the development of more MGs with high GFAs.
10.1007-s10853-020-04812-2	-1		A modified thermodynamic approach to describe melting in isolated nanoscale materials is suggested. The Gibbs free energy change of nanoscale alloy particles is modeled as a function of composition, temperature and nucleus and particle sizes. Cu-Ni has been chosen as a model system due to the availability of thermodynamic data within the high-temperature interval 1300-1600 K. For the first time, melting loops in the temperature-composition phase diagram were calculated for nanoparticle of 25 and 80 nm, respectively. It is shown that such loops represent the equilibrium two-phase solid-liquid states and do not coincide with the limiting solubility curves-the solidus and the liquidus. This new finding leads to the melting loop concept concerning phase diagrams of nanoscale alloys introduced in this paper. It is found that Cu-Ni nanoparticles can melt in different ways, whereas the dominant transition mechanism is surface-induced melting that initiates from the surface and then proceeds toward the core region. The decrease in size causes also a change of the melting temperature, the temperature width of the phase transition, the solubility limit, the concentration width of the melting loop as well as a change of the shape and slope of the equilibrium curves of the two-phase region of the phase diagram. As expected, when the size of the nanoscale particle increases, the solidus temperature increases and the size-dependent phase diagram approaches the bulk phase diagram.
10.1007-s10853-021-06093-9	-1		Immiscible alloys, whether in well-mixed or layered forms, are of increasing interest based on their novel structural and functional properties, such as enhanced thermal stability against grain growth or radiation-induced defect trapping at the interfaces. To address the need for new approaches to tailor microstructures, the microstructural development of an immiscible Cu-4 wt% Nb alloy processed via friction consolidation of elemental powders is investigated. Friction consolidation is a solid phase processing technique that imparts severe plastic strain into a deforming volume resulting in elevated temperatures below the melting temperature of the alloy. Two distinct processing pathways were chosen to understand the effect of thermomechanical conditions on the final microstructure. The microstructure was characterized using scanning electron microscopy, scanning transmission electron microscopy, and X-ray diffraction techniques. Path 1 exhibited larger strain, strain rate, and temperature as compared with path 2. In path 1, agglomerated Nb particles were present in the recrystallized ultrafine-grained Cu matrix, while in path 2 extremely fine and dispersed Nb particles were present in a highly deformed Cu matrix. In both pathways, supersaturation of Cu in Nb lattices was noted, but not vice versa. The asymmetry in mixing is explained based on deformation-based, thermodynamic and kinetic factors. These findings provide a pathway for creation of novel tailored microstructures and improved properties in any number of binary immiscible alloy systems.
10.1007-s10853-021-06251-z	-1		High-strength and high-conductivity Cu alloys are widely required in railway and lead frames. As a conventional element, Si reduces the electrical conductivity of Cu alloys significantly. In this work, Co is introduced into Cu-Si alloys for improving the mechanical and electrical properties. The results show that the Co-containing alloy possesses much higher hardness and conductivity than the Co-free alloys. The added Co reacts with Si to produce high density of CoSi nanoprecipitates that have a semi-coherent interface with the Cu matrix in the aged Cu-Co-Si alloy. The presence of CoSi nanoprecipitates is sufficiently verified by X-ray, energy-dispersive spectrometer and electron diffraction pattern. The formation of CoSi nanoprecipitates can pin dislocation motion, prevent the recrystallization and reduce the Si solute concentration in the Cu matrix. The effects of precipitate hardening and precipitation purification from CoSi phase result in the better performance of the aged Co-containing alloy than the Co-free alloys. The success in Cu-Co-Si alloys opens a door to overcome the disadvantage of Si alloying in Cu-based alloys. [GRAPHICS] .
10.1007-s10853-022-06879-5	2	corrosion; surface; film; electrochemical; films; spectroscopy; layer; current; solution; potential; resistance; composition; x-ray; ions; showed	Copper and its relevant species, such as oxides and many alloys, have been recognised as potential antibacterial surfaces. Despite the relatively low antibacterial efficacy of cuprous oxide (Cu2O) compared to pure copper, it is still worth consideration in some scenarios. Taking copper-nickel co-sputtered thin films with two copper contents (55 and 92 at%) as examples, this work investigated the potential of oxidation in altering the antibacterial behaviour of copper alloy surfaces. By heat treatment at 200-250 degrees C for 20-24 h, a layer mainly composed of Cu2O was successfully fabricated on the top of the Cu-Ni alloys. Antibacterial efficiency against Escherichia coli in 1 h was obtained by the droplet method and further compared. The coupons with 92 at% copper became less effective after oxidation: the reduction rate declines from 97.0 to 74.3%; whereas the coupons with 55 at% copper showed a large increase after oxidation, rising from 15.0 to 66.8%. The experiments described herein reveal a promising concept of oxidation in enhancing the less effective copper alloy surfaces for antibacterial applications. [GRAPHICS] .
10.1007-s10853-022-07137-4	-1		Selective laser melting (SLM), a laser powder-bed fusion technique, shows unique heterogeneous microstructures because of the complex thermal history they experience during layer-wise part fabrication. The current work attempts to establish the influence of these microstructures on the corrosion behavior of the SLM processed CuSn alloy. The as-built SLM samples showed heterogeneous epitaxial columnar grains, fine cellular dislocation structure (similar to 600 nm) with cell boundaries having higher dislocation density and solute Sn concentration than the cell interior, super-saturated solid-solution with similar to 6.5 wt% of Sn in Cu, and fine second-phase delta (Cu41Sn11) similar to 200 nm. The SLM microstructures affected the corrosion behavior of the CuSn alloy: the as-built samples showed high corrosion rate than the post-SLM heat-treated fully recrystallized samples. The effects of the residual stresses, cellular segregation, and second-phase delta (Cu41Sn11) on the corrosion behavior are minimal. The dislocation density and distribution primarily control the corrosion behavior of the SLM processed CuSn alloy. The partially recrystallized microstructures with heterogeneous dislocation distribution showed an increased corrosion rate.
10.1007-s10853-022-07450-y	-1		Nanoporous metallic foams (NMFs) of Cu, Cu-Zn, and Cu-Ni alloys with relative densities between 0.5 and 14% were created by polymer templating followed by thermal treatments for calcination and reduction. The mechanical strength of NMFs can be dominated by chemistry and morphological parameters, including the relative density, ligament size, and chemistry. An analysis by Pearson correlation coefficients found the predominant factors in the strength, as measured with nanoindentation, of the alloys NMFs were largely controlled by the relative density. The modulus of a Cu75Ni25 alloy with a relative density of 14% was 57% greater and its hardness was 64% greater than the same alloy with a 0.5% relative density. When foams with similar ligament size and relative density but different chemistries were compared, second phase particles in the form of ZnO in Cu-Zn alloys strengthened NMFs alloys significantly more than solid solution strengthening in Cu-Zn or Cu-Ni alloys. This suggests solid solution strengthening will have limited effectiveness in increasing the strength of NMFs, and precipitation hardening should be more impactful in creating stronger NMFs.
10.1007-s10853-022-07910-5	-1		The Cu-Fe-P alloy is the mainstream material of IC lead frame at present, which plays a key role in electrical signal transmission and mechanical fixation between bearing chip and external circuit board. With the development of integrated circuits toward high integration and extreme miniaturization, copper alloy strips for lead frames are required to have excellent electrical and mechanical properties, as well as excellent softening resistance under short-term high temperature service conditions. In this paper, the effects of annealing temperature (300, 400, 500 degrees C) on texture orientation and strength, and precipitates characteristics (morphology, size, interfacial relationship, etc.) of as-cold rolled Cu-2.18Fe-0.03P alloy were studied by means of EBSD and TEM. It is found that annealing at low temperature does not change the texture type, but it affects the texture strength compared with the as-cold rolled alloy. Cubic texture {001} < 100 > and R-type texture {111} < 112 > appear in the annealed alloy. The texture strength increases with the increase in annealing temperature, and the preferred orientation is more obvious. In addition, we found that there are two kinds of precipitated phases in the copper matrix, namely spherical alpha-Fe phase and irregular Fe3P phase. We further find out the coexistence state of the two precipitates and their evolution with annealing temperature. With the increase in annealing temperature from 300 to 500 degrees C, the size of the main strengthening phase alpha-Fe increases and the orientation relationship between alpha-Fe phase and the matrix changes from coherent to semi-coherent. On this basis, we found that the decrease in texture strength, the change of coherence relationship of alpha-Fe phase, and the decrease in dislocation barrier are the main factors leading to the softening of Cu-2.18Fe-0.03P alloy at high temperature. The research results of this paper are meaningful in guiding the development of high-end copper alloy strip in the field of electronic information.
10.1007-s10853-022-08087-7	15	aging; strength; conductivity; electrical conductivity; electrical; mpa; treatment; strengthening; degrees; cu-; cold; precipitation; tensile strength; tensile; iacs	A novel precipitation strengthening Cu-Fe-Zr alloy was designed and prepared based on the results of calculation of the phase diagram. After solid solutionizing, rolling and aging at 450 ?degrees C for 1 h, the alloy had a tensile strength of 515 MPa and an electrical conductivity of 72% IACS. There were two kinds of precipitates in the alloy after aging at 450 degrees C for 1 h . Fe precipitates with an average diameter of 4.3 nm were present in the deformed grains. Fe2Zr precipitates with an average diameter of 29.1 nm were present in the recrystallized grains. Both the Fe and Fe2Zr precipitates had coherent interfaces with the Cu matrix. The precipitation kinetics and effects on the properties of the alloy were discussed. It is found that the cold rolling enhanced the driving energy of precipitation. The precipitation of Fe and Fe2Zr had a dominant effect on the increase in electrical and mechanical properties of the alloy.
10.1007-s10853-023-08223-x	12	thermodynamic; ternary; phase; data; experimental; equilibria; phase equilibria; liquid; binary; experimental data; calculated; phases; literature; model; calphad	The phase equilibria and solidified microstructure of Cu-Cr-La system were investigated by a combination of key experiments and thermodynamic calculations. Six Cu-Cr-La ternary alloys were utilized to determine the solidified microstructure, isothermal section at 850 degrees C and phase transition temperatures along 5.0 at% La by means of X-ray diffraction, scanning electron microscopy, electron probe micro-analysis and differential scanning calorimetric techniques. By considering the present measured equilibrium data, the thermodynamic description for the Cu-Cr-La system was established via CALPHAD approach . The calculated phase relationship and phase fractions in equilibrium state shows a satisfactory agreement with the determined data. After that, the non-equilibrium solidification curves in different series Cu-Cr-La alloys were simulated with the Scheil-Gulliver model. The effects of La or Cr additions on the solidification sequences, phase transition temperatures and phase fractions in Cu-Cr-La alloys were analyzed. It is believed that the present work offers a theoretical basis for the novel design of Cu-Cr-La alloys.
10.1007-s10853-023-08287-9	0	solidification; phase; magnetic; magnetic field; undercooling; field; liquid; separation; peritectic; immiscible; cu-; dendrite; phase separation; microstructure; primary	The particle size distribution and solidification of dispersed Cu-rich particles within the core region of stable core shell microstructures in drop tube processed metastable Cu-50 at. % Co alloy was studied with a view of understanding the evolution and growth of these microstructures. Microstructural evidence indicates that the formation of the core shell microstructures is highly influenced by nucleation and growth phenomenon. Coalescence propelled by collision is favoured in smaller droplets owing to their higher cooling rates and subsequent higher degree of undercooling to facilitate the liquid phase separation process. Weaker Marangoni motion impeded the further convergence of the Cu-rich particles within the core region. [GRAPHICS]
10.1007-s10853-023-08295-9	-1		Cold angular rolling process (CARP) has emerged as a potential continuous severe plastic deformation technique enabling the processing of bulk metal sheets with improved mechanical properties. The CARP technique involves a combination of cold rolling of a sheet by a single rotation roller followed by equal-channel angular pressing of the sheet passing through a bent channel. The present work uses finite element method (FEM) to model CARP by considering processing conditions, including different friction values and processing velocities for different copper and stainless steel alloys. The simulations reveal the influence of these processing parameters on distributions of strain, strain rate, stress (in both the metal sheet and the CARP tool), temperature, and torque requirements through one pass of CARP on the metal sheets. The modeling results are validated by the experimental characterization of the hardness distribution and microstructure after CARP on a copper sheet. The results from FEM are used to estimate the energy incorporated into different metal alloys at various processing conditions. Finally, this study discusses the feasibility of scaling up the CARP technique. [Graphics]
10.1007-s10853-023-08367-w	-1		Residual stress greatly influences the warping behavior of lead frame copper alloys and can be evaluated by nanoindentation. In this study, the residual stresses are calculated by Suresh's model, Wang's model, and Ghanbari's model. In addition, an elastic work model, based on indentation unloading curve, is proposed. The results reveal that the residual stresses of all samples are determined to be compressive stresses. Furthermore, Wang's model and the elastic work model may be considered to be most appropriative for the residual stress assessments in lead frame copper strips. More importantly, for the lead frame copper alloys, there will be an obvious pile-up effect during the indentation process. This effect is utilized to correct residual stresses in Suresh's model, and identified that residual stresses decrease by about 300 MPa. This study has great significance for the development of the residual stress models by nanoindentation.
10.1007-s10853-023-08703-0	-1		The effect of vanadium (V) element on the kinetics and mechanism of continuous precipitation in Cu-3.2Ti-0.2Fe alloys was elucidated using X-ray diffraction, high-resolution scanning transmission electron microscopy, calculation of precipitation activation energy and wavelength of spinodal decomposition. The results show the wavelength of spinodal decomposition decreased from 5.7 to 1.2 nm, and the corresponding activation energy increased from 41.7 to 119.5 J/mol with the addition of V element increased from 0 to 0.3 wt%, performing severe inhibition on the continuous precipitation. Moreover, the hardness of the aged alloys was enhanced because of the refinement of V element on the precipitates, the Vickers hardness of the Cu-3.2Ti-0.2Fe-0.2 V alloy aged at 450 & DEG;C for 4 h was 38 HV0.2 higher than that of alloy without V addition. Whereas the striking contrast of the phase boundary between part precipitates and Cu-matrix in the close-packed (111) plane and coherent boundary was observed in the HR-TEM images of alloys with V addition, the precipitation mechanism of counterpart was formed not via spinodal decomposition but based on the nucleation and growth mechanism within higher precipitate activation energy.
10.1007-s10853-023-08817-5	-1		Nanoporous metals can serve in unique functional applications due to their high surface area, and they are often made through dealloying, which removes a sacrificial element through chemical etching and leaves a nanoporous matrix of the Nanoporous metals can serve in unique functional applications due to their high surface area, and they are often made through dealloying, which removes a sacrificial element through chemical etching and leaves a nanoporous matrix of the remaining element(s). Several variations on this technique allow for a wider variety of metals and alloys to be processed, but simple, scalable, and reliable production of nanoporous devices is still not a reality using the majority of techniques and alloy systems. Oxide reduction may provide a suitable alternative, and in this work, nanoporous Cu was produced via oxide reduction in the Cu-CuO system. This method uses mechanical milling to create a metal matrix composite powder primarily composed of CuO that is reduced under hydrogen to leave pure Cu behind. It requires no harsh chemicals, and it uses modest temperatures and short reaction times. Furthermore, it is fully compatible with traditional powder metallurgy, making it readily scalable. Powder compacts were also processed to track the geometric changes associated with each composition and demonstrate that device creation is feasible, even with the basic process applied here. This work reveals important parameters associated with these materials by incorporating a wide range of milling times and compositions, with shorter milling times and higher oxide concentrations providing the finest pore sizes, the highest porosity, and the greatest simplicity.
10.1007-s10853-023-08942-1	14	strength; properties; conductivity; electrical; mechanical; cu-; grain; mpa; electrical conductivity; aging; precipitation; phase; mechanical properties; tensile; phases	This study presents a comparative analysis of texture evolution, deformation mechanisms, and dislocation density evolution in pure copper, Al-1100 alloy, and Mg AZ31 alloy subjected to equal-channel angular pressing (ECAP). For that purpose, a unique grain fragmentation model combining continuum dislocation dynamics with Taylor-Lin crystal plasticity is presented. Copper and aluminum alloys, with their face-centered cubic (FCC) crystal structures, exhibit similar micromechanical processes during grain fragmentation. The post-ECAP textures for both materials align with ideal orientations, indicating a rotation of grains around the center of the flow direction. On the other hand, the magnesium AZ31 alloy, with its hexagonal close-packed (HCP) crystal structure, displays a rolling-like texture. Al-1100 showed high dislocation multiplication rate favored by dislocation glide, while Mg AZ31 displayed slower dislocation density evolution at 200 degrees C which can be associated with dynamic recrystallization and twinning low activity. Indeed, driven by elevated temperatures, dynamic recrystallization could form new grains, resulting in a gradual increase in dislocation density. Furthermore, the comparison of average grain size reduction rates aligns with the dislocation density findings, with aluminum alloys experiencing significant grain fragmentation and Mg AZ31 alloy undergoing the slowest rate of grain fragmentation. The employed continuum dislocation dynamics (CDD) coupled with a crystal plasticity modeling approach enables the prediction of material responses, offering a powerful tool for understanding and optimizing deformation behavior. Further research opportunities lie in exploring additional factors and refining the understanding of deformation behavior in FCC and HCP materials, as well as expanding the applicability of the modeling approach to other materials and processing techniques.
10.1007-s10853-023-09054-6	-1		The microstructure of ferromagnetic phase usually has an essential influence on the soft magnetic properties. In the present study, the effects of Si element, cold deformation and heat treatment on the microstructure of Fe-rich phase and soft magnetic properties of Cu-10Fe alloy were investigated. The results showed that the addition of Si caused more formation of alpha-Fe solid solution, as well as its morphology transformation from developed dendrites to cellular dendrites. The saturation magnetization thus increased to 17.28 emu/g and the coercivity decreased to 15.75 Oe. After rolling deformation and aging treatment, Fe-rich phase was further precipitated and generated the < 100 > preferred orientation, leading to the improvement of saturation magnetization to 18.39 emu/g, increased by 29.8% compared with the as-cast Cu-10Fe alloy. While after rolling deformation and aging treatment, the coercivity was 12.17 Oe, significantly reduced by 55.7%. The refinement of secondary precipitated Cu-rich phase and the decrease of dislocation density were responsible for the improvement of coercivity.
10.1007-s10853-023-09328-z	-1		During the high pressure torsion (HPT) of a material, a steady-state is reached after a certain number of the plunger revolutions. This steady-state is determined by the dynamic equilibrium between the formation of crystal lattice defects during deformation and their relaxation. In particular, during HPT of binary solid solutions, the competition takes place between the dissolution of particles of the second phase (and enrichment of the solid solution), on the one hand, and the decomposition of the solid solution (and precipitation of the second phase), on the other hand. As a result, a certain steady-state concentration of the second component css appears in a binary solid solution during HPT. This concentration is equifinal, it depends only on the HPT conditions, but not on the initial state of the binary alloy. In copper-silver alloys subjected to HPT at room temperature, this concentration is css = 5.5 wt% Ag (Acta Mater.195 (2020) 184). It can be expected that a change in the HPT temperature should shift the dynamic equilibrium and change the css concentration. In this work, we annealed the samples of Cu-8 wt% Ag alloy at 790 degrees C, 300 h and at 500 degrees C, 770 h . After annealing at 790 degrees C almost all silver atoms were diluted in copper matrix. After annealing at 500 degrees C all silver atoms were in the precipitates and copper matrix was almost pure. The annealed samples were subjected to the HPT at 6 GPa, 1 rpm, 300 K and 77 K. After HPT the silver concentration css in the first sample decreased and in the second one increased. It turned out that the steady-state concentration css indeed changed with decrease of HPT temperature from 300 to 77 K. It decreased to css = 3.9 wt% Ag. It means that the dynamic equilibrium between dissolution and precipitation of silver atoms is shifted, and precipitation prevails at 77 K. HPT also changes the size of silver precipitates. The big precipitates dissolve and small ones grow. Thus, the size of silver precipitates also comes from the top and from the bottom to the steady-state one (about 50 nm).
10.1007-s10853-024-09552-1	14	strength; properties; conductivity; electrical; mechanical; cu-; grain; mpa; electrical conductivity; aging; precipitation; phase; mechanical properties; tensile; phases	In recent developments, Cu-Cr-Nb alloys have emerged as promising materials offering a desirable balance between mechanical properties and electrical conductivity, rendering them suitable for intricate high heat flux applications. However, the laser additive manufacturing of Cu-Cr-Nb alloys has encountered notable challenges, primarily stemming from limitations associated with Cu-Cr-Nb alloy powders. Recognizing the pivotal role of powder feedstock in additive manufacturing, this study exerts the utilization of ball milling techniques to tackle pertinent challenges. Specifically, a kind of powder obtained by mechanical ball milling of elemental powders of Cu, Cr and Nb is employed to fabricate Cu-Cr-Nb raw materials, which exhibits a distinctive sesame ball structure and effectively mitigates the inherent high reflectivity of Cu powder. The resulting milled powder represents a notable departure from the conventional reliance on argon gas atomization for Cu-Cr-Nb alloy powder production. Then the study encompasses the fabrication of five distinct Cu-Cr-Nb bulk alloys, ranging from Cu-1Cr-0.5Nb to Cu-12Cr-6Nb, using laser directed energy deposition. The as printed Cu-Cr-Nb alloys exhibit commendable density, surpassing 99% based on visual analysis, and demonstrate mechanical properties akin to casts achieved through traditional melting and powder metallurgy methods. Notably, Cr2Nb particles were observed within all bulk alloys, with their size increasing proportionally with the Cr + Nb content. Tensile strength demonstrated a positive correlation with Cr + Nb content, while elongation and conductivity exhibited an inverse relationship. These findings hold considerable promise for advancing the utilization of Cu-Cr-Nb alloys in various applications requiring tailored performance characteristics.
10.1007-s10853-024-09855-3	-1		The ordered gamma '-(Ni, Cu)(3)Al is a crucial strengthening phase that improves the high-temperature resistance of Cu-based alloys, so it is important to predict the kinetic evolution of the composition and microstructure of the phase for high-temperature applications. Herein, this paper discusses the temporal evolution of the composition and coarsening of the gamma ' phase in a model ternary Cu50Ni37.5Al12.5 (at%) alloy during isothermal aging at 600, 700, 800, and 900 degrees C for 1-36 h . It is found that the gamma ' phase composition evolves linearly toward a binary gamma ' phase as the aging time increases during the process of aging at 800 and 900 degrees C, which cannot be predicted by the ternary phase diagrams alone. Meanwhile, through the utilization of the aforementioned linear law, the gamma phase composition can be predicted at a given temperature within the alloy by determining the volume fraction of the gamma ' phase. Additionally, the activation energy for coarsening decreases, and the coarsening rate of the gamma ' phase increases owing to the higher diffusion rate of Cu at high temperatures. The addition of microalloying elements with strong enthalpic interactions is beneficial for reinforcing the structural stability of the gamma ' phase. This work provides a simple method for the compositional analysis and performance prediction of Cu-Ni-Al alloys at elevated temperatures and sheds light on the subsequent compositional design and optimization of Cu-based high-temperature alloys.
10.1007-s10853-024-09983-w	0	solidification; phase; magnetic; magnetic field; undercooling; field; liquid; separation; peritectic; immiscible; cu-; dendrite; phase separation; microstructure; primary	Liquid-phase sintering of Cu-30 wt% Co alloy, involving liquid Cu coexisting with solid Co particles, was performed with and without a 12 T magnetic field. The microstructure evolution and coarsening behavior of polycrystalline Co particles during the sintering were investigated. The Co particle size increased with increasing sintering time, both with and without the high magnetic field; however, the application of the high magnetic field led to larger Co particles through a higher coarsening velocity. Additionally, under the high magnetic field, chain-like Co particle structures were formed. The coarsening and chain-like structure of the polycrystalline Co particles in the high magnetic field could be linked to the alignment of the magnetic domains in the particles and the induction of magnetic dipole-dipole interactions between particles, which promoted contact between Co particles. This study provides guidance and reference for the use of high magnetic fields to control liquid-phase sintering of polycrystalline particles.
10.1007-s10853-024-10109-5	-1		Nanolayered Cu-Ag eutectic alloy is a promising radiation protection material due to its favorable mechanical properties and resistance to radiation rays. These unique properties can be attributed to its high density of interfaces in the nanoscale: from phase interface between copper and silver layers to nanoscale grain boundaries dividing the multiple eutectic grains. However, to date, the coupling effects of phase interface and grain boundary within the nanolayered Cu-Ag eutectic alloy have not been well investigated. Therefore, we employ molecular dynamics (MD) simulations to elucidate the interface-dominated mechanical response and microstructural evolution of this eutectic material system under tensile loadings. In our simulations, the mechanical responses of nanolayered Cu-Ag eutectic alloy under tension have shown four different stages based on varied dislocation motion modes: linear elastic stage, yield stage I (confined layer slip), yield stage II (interface crossing), and plateau stage. Throughout all the stages, interfaces exhibit dominant influence on the deformation of the alloy. Particularly, the grain size and layer thickness characterized by grain boundary and phase interface activity have shown intricate impact on the strength of the alloy, which is due to the competitive relation between interface activity and dislocation motions. In addition, diverse grains perform differently in both interface shear and dislocation propagation, contributing to the plastic deformation for the model. Finally, this study reveals the link between mechanical behavior and microscopic interfaces of nanolayered Cu-Ag eutectic alloy and sheds light on the synthesis processes for the material.
10.1007-s10853-024-10498-7	-1		Copper alloys are at the forefront of alloy innovation, as they possess outstanding strength and unparalleled electrical conductivity. This papers sequentially reviews current strategic approaches that have successfully balanced the attainment of both strength and conductivity in copper alloys in the Cu-Fe-Si system. These approaches involve fine-tuning the composition and utilizing hierarchical multi-scale microstructural templates. This work provides a comprehensive assessment of the important developmental stages of high-strength conductive copper alloys in the Cu-Fe-Si system. This study emphasizes the relationship between composition, microstructure, and mechanical and electrical properties by implementing a cost-effective rapid casting method with alloying procedures and conducting extensive electron microscopy for microstructural characterization. The full research yields valuable insights that may be used to optimize copper alloys for a wide range of applications that demand both strength and conductivity. Furthermore, the present study additionally enhances our understanding of the phase transformation events in the alloy system by including novel microstructural observations. The current paper also presents novel findings about sustainable performance and real-time engineering applications, specifically in connection to creep qualities and their link with microstructure. This paper explores the complex relationship between the composition of alloys and the process of refining their structure. The knowledge acquired provides a foundation for creating customized alloys that are well-positioned to suit the changing requirements of various industries, including aerospace and electronics.
10.1007-s10853-025-10797-7	-1		Cu-Ti alloy, as a typical aging strengthening alloy, possesses the high strength and wear resistance, widely used in engineering applications. However, the conductivity of Cu-Ti alloy significantly decreases when the content of Ti exceeds 4 wt%, which is due to the scattering effect of lattice distortion of the matrix on electrons caused by the difference in atomic radius between Cu and Ti. The precipitation of in situ dispersive nano-Cu-Ti-O compounds particles and heat treatment is expected to reduce lattice distortion of matrix and improve the strength of materials. We employed Cu2O as the oxygen source to generate oxide particles to reinforce Cu-Ti composites through an internal oxidation process. The influence of solid solution time on the microstructure and properties of nano-oxide- reinforced Cu-Ti composites is explored, and the composition of oxide particles is Cu2Ti4O with a size of approximately 100 nm, which has a good interface bond with matrix. The strength reaches 675 MPa when the solid solution time is 16 h, and the strengthening mechanism and conductivity improvement mechanism were discussed. Actually, Ti atoms precipitated as beta '-Cu4Ti and Cu2Ti4O, reducing lattice distortion of the matrix and increasing electrical conductivity after solid solution and aging treatment. This study provides a novel approach for preparing nano-oxide-reinforced Cu-Ti matrix composites.
10.1007-s10853-025-10807-8	-1		The poor hot workability of Cu-Ti alloys has become a bottleneck restricting the further improvement of properties and applications. In this work, the coupling effects of grain structure, precipitates and solid solubility on the hot deformation behaviors of Cu-3.18wt%Ti alloy were deeply studied. Our results show that based on the obtained constitutive equation and thermal activation energies, the corresponding hot workability maps of alloy can be established and used to guide the designation of hot working process. The complex interactions that occur between dislocation and precipitates lead to the differences in dynamic recrystallization (DRX) and precipitation for the changed strain rates and temperatures. The deformability can be improved by coupling control of DRX and dynamic precipitation. The corresponding mechanisms of hot deformation and microstructural evolution of grain structure, precipitates and solid solubility of Ti in the matrix during the hot deformation has been put forward. Our results provide fundamental insight into the DRX, precipitation and coordinated deformation of Cu-Ti alloys with poor deformability, as a function of hot strain.
10.1007-s10853-025-10865-y	0	solidification; phase; magnetic; magnetic field; undercooling; field; liquid; separation; peritectic; immiscible; cu-; dendrite; phase separation; microstructure; primary	During preparation of metallic material, solute migration has a significant effect on the microstructure. High magnetic field has an enormous potential on controlling alloy solidification on the basis of Lorentz force, magnetic force, etc. In this work, directional solidification experiments of a Cu-73.4 wt% Ag alloy have been conducted under different gradient magnetic fields. The effects of gradient magnetic fields on the solute migration and microstructure evolution of the alloys during the directional solidification process have been investigated. Without magnetic field, the alloy showed an aligned dendritic microstructure. Under a uniform magnetic field, the dendritic microstructure transformed to a eutectic morphology. Under a gradient magnetic field, the alloy exhibited again the dendritic microstructure, but with poor alignment. The transformation of the microstructure from aligned dendritic to eutectic to poor aligned dendritic morphology can be attributed to the combining effects of the Lorentz force and magnetic force on the migration of Cu solute at the solid/liquid interface. The results of this work provide a new insight to regulating the microstructure of alloys using high gradient magnetic fields.
10.1007-s10853-025-11104-0	-1		Grain boundary segregation engineering is widely used as a means to control grain boundary stability and material strength . In this work, the effect of grain boundary segregation with different contents of Ni atoms on the mechanical properties of Cu-Ni alloy was studied by molecular dynamics (MD) method. It was found that the increase in material strength was mainly due to the alloying of the system and the fact that the segregation of Ni atoms at the grain boundaries could reduce the grain boundary energy and improve the stability of the grain boundaries. When the content of Ni atoms is 20%, the tensile strength and yield strength increase to 2.34 GPa and 2.31 GPa respectively. With the increase of Ni atom content, the grain boundary migration phenomenon is alleviated, and the grain boundary migration distance is shorter. Meanwhile, the dislocation density decreases with the increase of Ni atom content. As the barrier of grain boundaries to dislocations is strengthened, dislocations form obvious aggregation areas, and the intracrystalline deformation is mainly Shockley partial dislocation slip. The above results lay a foundation for the further application of Cu-Ni alloy.
10.1007-s10853-025-11220-x	15	aging; strength; conductivity; electrical conductivity; electrical; mpa; treatment; strengthening; degrees; cu-; cold; precipitation; tensile strength; tensile; iacs	This article investigated in detail the effect of P content on the microstructure and properties of Cu-Ni-Fe-P alloys. Through systematic alloy design, the alloys with P contents ranging from 0.13 to 0.22 wt% were prepared. The results revealed that P element promoted the formation of fine precipitation phases (Ni, Fe)2P and refined the grain size. As the P content increased, the tensile strength and hardness first increased and then decreased, while the electrical conductivity gradually decreased. When the P content was 0.16 wt%, the comprehensive performance was optimal. The conductivity and tensile strength of Cu-0.3Ni-0.3Fe-0.16P alloy were 62.3%IACS and 645 MPa, respectively, through cold rolling 90% reduction (90%CR) + aging (AG 450 degrees C x 4 h) + 60%CR. Compared to Cu-0.3Ni-0.3Fe-0.19P alloy, the tensile strength and conductivity increased by 62 MPa and 5.9%IACS, respectively. When the P content was 0.16 wt%, there was a significant increase in deformation strengthening and second phase strengthening. The softening of Cu-Ni-Fe-P alloys were closely related to the recrystallization and coarsening precipitation. This study provided a theoretical basis for the rational design of Cu-Ni-Fe-P alloys with controllable microstructure and properties, suitable for lead frames and microelectronic applications.
10.1007-s10853-025-11534-w	-1		Bulk pure Cu and Cu-5Fe (wt%) materials were successfully fabricated at room temperature by powder consolidation using high-pressure torsion (HPT) processing through 30 turns under a pressure of 6 GPa. The microstructure, texture and mechanical properties of the fabricated bulk discs were systematically characterized across their diameters using electron backscatter diffraction, scanning electron microscopy, transmission electron microscopy, X-ray diffraction and Vickers microhardness. Additionally, their thermal stability was evaluated after annealing treatment at 500 degrees C for 6 h . The results show that two grain refinement stages occurred in the Cu disc accompanied by the formation of partial A-fibre (A1 & lowast;\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$${A}_{1}<^>{*}$$\end{document}/A2 & lowast;\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$${A}_{2}<^>{*}$$\end{document} and A components). The dynamic recrystallization was delayed in the Cu-5Fe disc owing to the pinning effect of Fe content. Consequently, the grain refinement was more effective, and the texture gradually developed the B, A and A1 & lowast;\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$${A}_{1}<^>{*}$$\end{document} components. The Cu-5Fe disc was harder than the Cu disc, and the microhardness increased across the disc diameter. Rapid grain growth with a high amount of Cu2O oxide and retained texture were the main characteristics of the annealed Cu disc. The precipitation of Fe phase during annealing led to the development of a duplex microstructure at the centre and mid-radius positions and a stable microstructure at the edge of the Cu-5Fe disc. Eventually, the annealing texture was transformed into a complete A-fibre (A1 & lowast;\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$${A}_{1}<^>{*}$$\end{document}/A2 & lowast;\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$${A}_{2}<^>{*}$$\end{document} and A/A\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$\overline{A }$$\end{document} components) which was quite similar to the Cu disc. The microhardness decreased after annealing but it was more homogeneously distributed across the disc diameter than the HPT-processed disc. The results were discussed based on the different grain refinement mechanisms, static recrystallization mechanisms, solute elements, dislocations and annealing twins.
10.1007-s10854-012-0858-7	2	corrosion; surface; film; electrochemical; films; spectroscopy; layer; current; solution; potential; resistance; composition; x-ray; ions; showed	This study reports the preparation of Cu2ZnSnS4 (CZTS) thin films by magnetron sputtering deposition with a Cu-Zn-Sn ternary alloy target and sequential sulfurization. The effects of substrate temperatures on the structural, morphological, compositional as well as optical and electrical properties were characterized. The results showed the CZTS thin films prepared by sulfurization at substrate temperature of 570 A degrees C yielded secondary phases along with CZTS compound. The relatively good properties of CZTS thin film were obtained after sulfurization at substrate temperature of 550 A degrees C. This CZTS film showed compact structure with large grain size of 900 nm, direct optical band gap of 1.47 eV, optical absorption coefficient over 10(4) cm(-1), resistivity of 4.05 Omega cm, carrier concentration of 8.22 x 10(18) cm(-3), and mobility of 43.38 cm(2) V-1 S-1.
10.1007-s10854-013-1422-9	2	corrosion; surface; film; electrochemical; films; spectroscopy; layer; current; solution; potential; resistance; composition; x-ray; ions; showed	Cu-Mn alloy films for microelectronic interconnects were deposited by H-2 reduction of bis(2,2,6,6-tetramethyl-3,5-heptanedionato)-copper(II) [Cu(tmhd)(2)] and bis(penta-methylcyclopentadienyl)-manganese [Mn(pmcp)(2)] in supercritical carbon dioxide (scCO(2)). 20-nm thick and continuous Cu-Mn films with a smooth surface were deposited at the temperature of 210 A degrees C. Manganese was found to be segregated to film surface and its content on the surface increased with increasing Mn precursor concentration in scCO(2). Mn addition by supercritical fluid deposition could improve surface quality of the Cu film. And electrical resistivity of the Cu-Mn films increased with the Mn contents in the film.
10.1007-s10854-013-1507-5	2	corrosion; surface; film; electrochemical; films; spectroscopy; layer; current; solution; potential; resistance; composition; x-ray; ions; showed	Cu2ZnSnS4 (CZTS) thin films were prepared by sulfurizing single-layered metallic Cu-Zn-Sn precursors which were deposited by DC magnetron sputtering using a Cu-Zn-Sn ternary alloy target. The composition, microstructure and properties of the CZTS thin films prepared under different sputtering pressure and DC power were investigated. The results showed that the sputtering rate of Cu atom increases as the sputtering pressure and DC power increased. The microstructure of CZTS thin films can be optimized by sputtering pressure and DC power. The CZTS thin film prepared under 1 Pa and 30 W showed a pure Kesterite phase and a dense micro-structure. The direct optical band gap of this CZTS thin film was calculated as 1.49 eV with a high optical absorption coefficient over 10(4) cm(-1). The Hall measurement showed the film is a p-type semiconductor with a resistivity of 1.06 Omega cm, a carrier concentration of 7.904 x 10(17) cm(-3) and a mobility of 7.47 cm(2) Vs(-1).
10.1007-s10854-014-2191-9	2	corrosion; surface; film; electrochemical; films; spectroscopy; layer; current; solution; potential; resistance; composition; x-ray; ions; showed	Ternary CuCoNi alloys were deposited by electrodeposition and the effect of different deposition potentials on the microstructural and magnetic properties of the alloys was investigated. The deposition potential was changed from -1.0 to -1.3 V versus saturated calomel electrode. Anomalous co-deposition occurred for all ternary alloys. All alloys have a face centered cubic (fcc) crystalline structure and the peaks of fcc Cu transformed to those of fcc Ni when the deposition potential was increased from -1.0 to -1.3 V, which was confirmed by the energy dispersive X-ray spectroscopy. The atomic Ni content of the ternary alloys increased from 8 to 33 % when the deposition potential was increased from -1.0 to -1.3 V. On the film surfaces, a specific growth orientation and micro-sticks gradually altered to spherical micro-grains when the deposition potential was increased. Saturation magnetization, M-s and coercivity, H-c of the alloys were significantly affected by different deposition potentials. The M-s value varied between 308 and 674 emu/cm(3) when the deposition potential was changed from -1.0 to -1.3 V. And, the H-c gradually decreased from 169 Oe to 112 Oe when the potential increased from -1.0 to -1.3 V. The changes in the magnetic properties of the alloys are related with the variations in the microstructural properties caused by deposition potential. Besides, the anisotropic magnetoresistance magnitudes were found to depend on the deposition potential.
10.1007-s10854-015-3355-y	-1		A cold-rolled Cu/Al clad ribbon was bonded on an electroless nickel immersion gold (ENIG)-finished Cu substrate by ultrasonic bonding. The bonding samples were subjected to harsh conditions such as thermal exposure at 200 A degrees C and thermal shock at -40/250 A degrees C. The microstructural evolution and textural transitions in the Cu/Al clad ribbons were analyzed using electron backscatter diffraction to understand the heel crack propagation mechanism. The heel cracks were initiated at the edge of the Al layer between the bonded and non-bonded zones and were propagated along the coarsened grain boundaries deep into the cladded Cu layer. The continuous dynamic recrystallization (CDRX) transition phenomena around the heel cracks were scrutinized by electron backscatter pattern analysis to reveal the different microstructural and textural evolutions as a function of the ultrasonic bonding process at the bonded part and of lift-up at the non-bonded part. The heel cracks were occurred by grain coarsening due to CDRX within the Al layer during the environmental tests. The region of coarsened grains by CDRX was extended with increasing test periods. Especially in the thermal shock tests at -40/250 A degrees C, severe grain coarsening was found involving significant transformation of sub-grains into grains by rapid CDRX development. Thus, heel crack propagation accelerated more during thermal shock cycles than during high-temperature storage.
10.1007-s10854-016-5036-x	2	corrosion; surface; film; electrochemical; films; spectroscopy; layer; current; solution; potential; resistance; composition; x-ray; ions; showed	The structure and magnetic properties of CuCo alloys electrodeposited in aqueous solution on n-type Si(100) substrates were investigated as a function of the trisodium citrate concentration in the electrolyte. The compositional analysis show that percentage of Co has a non-monotonic dependence on the increase in concentration of sodium citrate, with a maximum at 300 mM followed by a significant decrease The magnetic measurements in similar samples in terms of composition and thickness show that the coercive field value it differs greatly, from 87 to 20 Oe without and with added citrate, respectivelly, owing to the improved morphological quality and change in crystalline structure induced by the citrate. For electrodeposited films without citrate in the electrolyte, the X-ray diffraction pattern shows two peaks at 2 theta = 43.298 and 44.217 typical of fcc (111) planes for copper and cobalt, respectively, while in the presence of citrate only one peak characteristic of fcc of the CuCo alloy was observed.
10.1007-s10854-020-04906-2	4	transformation; martensite; martensitic; phase; shape; beta; memory; shape memory; temperature; temperatures; martensitic transformation; gamma; transformation temperatures; effect; thermal	The influence of simultaneous doping of Ti and B on the thermomechanical, structural, and magnetic properties of CuAlMn Heusler alloys was evaluated in this study. The samples were prepared via induction casting, and they were characterized by X-ray diffraction, differential thermal analysis, optical microscopy, scanning electron microscopy, mechanical microhardness tests, and magnetometry. The alloys presented the austenite phase with L2(1) + DO3 structures. It was found that the doping of TiB reduced the average grain size and increased the amount of second-phase precipitates, which was attributed to the low Ti solubility in the austenitic matrix. A reduction in the values of Curie temperature, melting temperature, melting enthalpy, and HV microhardness was observed with the doping of TiB to the CuAlMn ternary system. It was also verified that the simultaneous doping of Ti and B changed the magnetic behavior of the CuAlMn system from paramagnetic (with weak ferromagnetic contribution) to ferromagnetic order. Our results bring to light a new alternative to doping CuAlMn alloy, and improve the structural and magnetic properties, interesting parameters for technological applications.
10.1007-s10854-024-13491-7	-1		In this paper, crystallographic, morphological, mechanical, thermomechanical, and electronic properties of Cu-13.81%Mn-3.78%Al (wt%) alloy has been investigated under various conditions by distinct physical methods. Please check and confirm the edit made in the article title. As a result of surface and crystallographic investigations; precipitate phase is observed in the alloy. A Schottky diode based on Cu-Mn-Al alloy was fabricated. The electrical properties of the Schottky diode were investigated using transient photocurrent, photoconductivity and photocapacitance analysis. Electrical properties showed sensitivity to different illumination intensities and frequencies. The Schottky diode showed negative capacitance (N.C.) behavior at reverse bias. This behavior is due to the loss of interface charges.
10.1007-s10854-025-14831-x	14	strength; properties; conductivity; electrical; mechanical; cu-; grain; mpa; electrical conductivity; aging; precipitation; phase; mechanical properties; tensile; phases	The effects of heat treatment and two-stage cold rolling on the microstructure, electrical conductivity, and stress relaxation resistance of Cu-0.3Be-0.5Co alloys was systematically investigated. The relationship between microstructural evolution and the electrical conductivity and stress relaxation resistance was determined by analyzing grain size, precipitates, and dislocation densities of the alloys in various states. After aging for 60 min at 450 degrees C and cold rolling for 50%, the Cu-0.3Be-0.5Co alloy achieved an electrical conductivity of 49.9% IACS, with stress relaxation rate of less than 10% within 100 h . The CR2 sample exhibited a significantly refined grain size, with numerous fine BeCo phases uniformly distributed within the matrix and a high density of dislocations surrounding the precipitates. The improvements in micro-hardness and electrical conductivity were primarily due to the precipitation of the BeCo phase. The stress relaxation process in Cu-Be-Co alloys consists of an initial dislocation interaction stage, followed by a stage involving dislocation-precipitate interactions. These findings have important implications for the development of low-beryllium Cu-Be alloys with high strength, good electrical conductivity and excellent stress relaxation resistance.
10.1007-s10856-005-4752-1	-1		Age-hardening behaviour and the related microstructural changes of a silver alloy with relatively high Cu content were elucidated by means of hardness test, X-ray diffraction (XRD), scanning electron microscopic (SEM) observations and electron probe microanalysis (EPMA). The microstructure of the solution-treated specimen was composed of the Ag-rich matrix, the Cu-rich particle-like structures containing Pd, and the lamellar structure of both phases. By the age-hardening heat-treatment, the Cu element began to precipitate from the Ag-rich matrix by the solubility limit, and the very fine Cu-rich precipitates became coarsened by further aging. The silver alloy with relatively high Cu content showed apparent age-hardenability. The hardness of the solution-treated specimen began to increase and reached a maximum value with increasing aging time, and then the hardness decreased gradually after maintaining the maximum value for short periods of time. The early stage of precipitation of the Cu-rich phase from the Ag-rich matrix seemed to have caused the increase in hardness. The decrease in hardness was attributed to the coarsening of the Cu-rich precipitates in the later stage of the age-hardening process. (C) 2005 Springer. Science + Business Media, Inc.
10.1007-s10856-018-6103-z	2	corrosion; surface; film; electrochemical; films; spectroscopy; layer; current; solution; potential; resistance; composition; x-ray; ions; showed	Copper-containing composite is a cupric ions release system to prepare a novel copper intrauterine devices (Cu-IUDs), its biocompatibility and weight of the prepared composite Cu-IUDs are directly relevant to its such side-effects as pain and bleeding. To improve its biocompatibility and reduce its weight of such a composite Cu-IUDs, a copper-containing composite based on polymer alloy of poly(ethylene oxide) (PEO) and low-density polyethylene (LDPE) is developed. Here the role of its PEO in this novel cupric ions release system is reported. The results show that its cupric ions release rate can be adjusted easily by only changing its PEO content, and it increases remarkably with the increase of its PEO content. Our study also show that this influence is caused by the improvement of its hydrophilicity and the formation of its porous structure owing to the introduction of PEO. The improvement of its hydrophilicity make it easier for the surrounding aqueous solution to infiltrate into the composite, and the formation of its porous structure provide more routes for entry of the aqueous solution and diffusion of the released cupric ions. All these results indicate that the Cu/PEO/LDPE composite is a potential material that can be used to prepare such cupric ions release micro-devices as Cu-IUDs with slighter side-effects through its smaller weight.
10.1007-s10909-012-0743-z	0	solidification; phase; magnetic; magnetic field; undercooling; field; liquid; separation; peritectic; immiscible; cu-; dendrite; phase separation; microstructure; primary	The influence of a 12 T high static magnetic field on microstructures of the proeutectic Cu dendrites in the diamagnetic Cu-Ag alloy has been investigated. Our experimental results show that the length of the Cu dendrites arm is decreased by 10 % and the dendrite arm spacing is increased when the Cu-25 %Ag alloys are solidified in a 12 T static magnetic field. The applied magnetic field also enriches the average weight percent of Ag in Cu dendrites. Our analysis demonstrates that these effects are essentially attributed to the solute redistributions and temperature gradients of the convection suppression by the electromagnetic forces.
10.1007-s10934-021-01128-7	-1		This study investigated the effects of the manufacturing process on the microstructure of nanoporous copper (NPC) produced using cold-rolled Mn-30 at% Cu and Mn-40 at% Cu precursor sheets. NPC was prepared by chemically dealloying these precursor sheets in a 4% HCl aqueous solution. The initial Mn-Cu alloys were homogenous solid solutions with good cold-rolling workability. After dealloying, Mn-30 at% Cu and Mn-40 at% Cu precursors formed nanoporous structures with ligament size of 122 +/- 5 nm and 97 +/- 4 nm, respectively. In addition, the annealing conditions of the precursors were strongly related to the formation of a bi-continuous nanoporous structure. This was attributed to the lower diffusivity of Mn atoms at 550 celcius than that at 750 celcius, which resulted in the slower rearrangement of Cu atoms during the dealloying process. Additionally, NPC sheets derived from annealed Mn-30 at% Cu precursors at different annealing temperatures under the same dealloying condition exhibited ligament sizes of 223 +/- 9 nm and 149 +/- 4 nm. These results indicate that the change in the annealing temperature of the precursor significantly refined the nanoporous structure.
10.1007-s10948-010-1034-z	4	transformation; martensite; martensitic; phase; shape; beta; memory; shape memory; temperature; temperatures; martensitic transformation; gamma; transformation temperatures; effect; thermal	In this study, the transformation temperatures and shape memory effect of Cu-Al-Mn shape memory alloys were investigated by calorimetric measurements. Cu-Al-Mn alloys in the range of 10-15 wt% of aluminum and 0-10 wt% of manganese; exhibiting beta-phase at high temperatures, were prepared. With an increase in the aluminum and manganese concentrations of the alloy, the martensite morphology is modified and the transformation temperatures are decreased. The activation energies of the alloys were calculated according to the Ozawa and Kissinger methods. Magnetic properties of the alloys were studied and it was seen that the alloys show low magnetization. The microstructures of the alloys were investigated by optical micrographs where the martensite variants with different orientations can be observed from the micrographs.
10.1007-s10948-010-1052-x	-1		The more than 20 years old Cu high-T (c) superconductors exhibit as undoped parent materials antiferromagnetism. Upon doping the long-range antiferromagnetism disappears and only short-range antiferromagnetic clusters remain which show a spin pseudo-gap. There are no good ideas why long-range antiferromagnetism disappears upon the appearance of superconductivity because antiferromagnetism and superconductivity are compatible. A breakthrough has come about with the discovery of a plutonium (Pu) containing alloy PuCoGa5 with a T (c) of 18.5 K. In principle not very exciting, but in the field of actinides T (c)'s are not more than 3 K because of the high mass and corresponding low phonon energies. The compound is a high-T (c) material in the field of actinides. But also this Pu-containing compound is a short-range antiferromagnet with a spin pseudo-gap. A pattern starts to develop! As well in the Cu as in the Pu compounds, some magnetic ions Cu2+ and Pu3+ are replaced upon doping with nonmagnetic Cu3+ or spontaneously with nonmagnetic Pu2+ ions, thus a mixed valence configuration appears with nonmagnetic states (spin holes) in antiferromagnetic clusters. The newly discovered Fe pnictide superconductors, however, have only one valence, Fe2+ above and below T (N), the N,el temperature of 150 K, as well above and below T (c), as judged by the isomer shift of the Mossbauer effect. However, doping with fluorine, replacing oxygen, not only introduces electrons, but changes locally the crystal field acting on the iron ions. Divalent iron 3d(6) has a high-spin configuration t(2)(4) e(2) in a magnetic Gamma(5) configuration and a nonmagnetic low-spin configuration t(2)(6) in a Gamma(1) state. So with the same valence we can have a magnetic and a nonmagnetic configuration, triggered by variation of the local crystal field induced by doping, causing again spin holes. We show that these spin holes in antiferromagnetic clusters have an attractive interaction and combine to make nonmagnetic bipolarons, which can condense and lead to superconductivity.
10.1007-s10948-016-3699-4	-1		In this paper, we reported the effect of heat treatment on the magnetic properties of Cu (75.8)-Mn (24.2) alloy (wt%) alloy. Magnetization measurements were performed by using a vibrating sample magnetometer (VSM) at 300 K temperature. Observations of the magnetization as a function of applied field and temperature were conducted between -10 and 10 T magnetic field ranges at constant temperature. Since the grain size is important in determining the magnetic properties of copper-based alloys, two different grain-sized samples were examined by using ac magnetic susceptibility measurements. The magnetic saturation and the coercivity values for the small-grained sample are found higher than those for the larger-grained sample. The magnetic saturation values at room temperature were found to be approximately 3.63 and 3.22 emu/g for large-grained and small-grained samples, respectively. Details of the morphological properties and chemical composition have also been examined by scanning electron microscopy (SEM) and energy-dispersive X-ray spectroscopy (EDX), respectively. In addition, X-ray diffraction (XRD) observations were performed for the determination of the crystallography of phases.
10.1007-s10948-016-3914-3	-1		In this study, the magnetic properties of both Cu85.41Al9.97Mn4.62 and Cu82.41Mn13.81Al3.78 (wt%) shape memory alloys were studied. The analysis of the magnetization as a function of applied field and temperature was conducted between -10 to 10 T magnetic field ranges at constant temperature. Two alloys were examined using ac magnetic susceptibility measurements. The magnetic saturation values at room temperature were found to be approximately 1 and 70 emu/g for Cu85.41Al9.97Mn4.62 wt%) and Cu82.41Mn13.81Al3.78 (wt%) alloys, respectively. The magnetic saturation and the coercivity values for the CuAlMn alloy are found smaller than those for the CuMnAl alloy. Moreover, from the magnetization curves, the typical ferromagnetic behavior were observed for both alloys. Details of the morphological properties and chemical composition have been examined by scanning electron microscopy (SEM) and energy-dispersive X-ray spectroscopy (EDX), respectively.
10.1007-s10948-017-4143-0	-1		In this work, the magnetic, structural, electrical and kinetic properties of the Cu-25.50%Mn-3.72%Zn alloy were studied. Chemical composition of the prepared alloy was determined by electron-dispersive spectroscopy (EDX). The other properties in the Cu-25.50%Mn-3.72%Zn alloy were studied using scanning electron microscopy (SEM), X-ray diffraction (XRD), differential scanning calorimetry (DSC), electrical resistivity (ER) and vibrating sample magnetometer (VSM). The obtained results from scanning electron microscopy observations showed that this alloy exhibits the grain structure with alpha + beta phases which appears as an alpha-precipitation copper-rich solid solution. The crystal structure and unit cell parameter of the alloy were determined from XRD pattern. The lattice parameter of this alpha phase is found to be as a = 0.3689 nm. The characteristic transformation temperatures, the thermodynamic parameters, and the activation energy values of the sample according to Kissinger and Augis-Bennett methods were determined by differential scanning calorimetry measurements. Also, the calculated activation energy values of the sample according to Kissinger and Augis-Bennett methods are compared with each other. The electrical resistivity values at different temperatures were also measured. The magnetic properties of Cu-25.50%Mn-3.72%Zn alloy were determined as a function of temperature and applied field existing from experimental data.
10.1007-s10965-018-1573-8	-1		Incorporating both a low-melting-point metal (LMPM) and a high-melting-point metal (HMPM) into a polymer is a promising approach to prepare highly conductive, melt-processable composites. The effects of the total content of the two metals on the structure and properties of the composites were studied in this work through a eutectic Sn-Cu alloy/Cu particles/polyamide-66 ternary system. The structure, conductivity, fluidity and toughness of the composites were characterized by scanning electron microscopy, four-point probe or two-electrode method, small amplitude oscillatory shear testing and Charpy impact testing, respectively. The results show that the morphology of metal phase in the composites transforms from isolated islands to a physically continuous network as the total metal content increases. The percolation threshold for the composites is lower than that of traditional metal-filled polymer composites. The complex viscosity and impact strength of the composites vary non-monotonically with the total metal content and exhibit a minimum. The enhancement in the conductivity and toughness of the composites is related to the formation of the physically continuous conductive network. Overall, the filler content dependences of the structure and properties of the LMPM/HMPM/polymer composites are different from those of traditional conductive polymer composites. The combination of LMPM and HMPM helps reduce the filler content and mitigate the composite fluidity deterioration.
10.1007-s10967-024-09819-6	-1		This study used the gamma transmission method to present a systematic experimental analysis of the mass (mu m)and linear attenuation coefficients (mu) of Cu-Al-Ni shape memory alloys. Gamma rays with energies of 0.511 MeV, 0.661 MeV, 1.173 MeV, and 1.333 MeV were, respectively, emitted from point sources 22Na, 137Cs, and 60Co. The results revealed a significant decrease in both the mass attenuation coefficient from 0.08 to 0.05 cm2g-1 and the linear attenuation coefficient from 0.65 to 0.40 cm-1 as the incident gamma energy increased from 0.511 to 1.333 MeV. The obtained experimental results were compared with theoretical data from established databases such as WinXCom and the Photon Shielding and Dosimetry (Phy-X / PSD). Moreover, seven further vital shielding parameters were calculated utilizing the mu m and mu of experimental and theoretical values including total atomic cross-section (sigma a), total electronic cross-section (sigma e), effective atomic number (Zeff), effective electron number (Neff), half (HVL), tenth value (TVL) layer, and mean free path (MFP) for the alloys at different photon energies. Comparative analysis indicated that these Cu-Al-Ni SMAs exhibit promising potential for nuclear applications, closely aligning with the alloys widely discussed in existing.
10.1007-s10973-006-7790-0	4	transformation; martensite; martensitic; phase; shape; beta; memory; shape memory; temperature; temperatures; martensitic transformation; gamma; transformation temperatures; effect; thermal	Thermal behavior of alpha-(Cu-Al-Ag) alloys, i.e. alloys with composition less than about 8.5 mass% Al, was studied using differential scanning calorimetry (DSC), differential thermal analysis (DTA), scanning electron microscopy (SEM), energy dispersive X-ray analysis (EDX) and X-ray diffractometry (XRD). The results indicated that the presence of silver introduces new thermal events ascribed to the formation of a silver-rich phase and, after addition higher amounts than 8 mass% Ag to the Cu-8 mass% Al alloy it is possible to observe the formation of the gamma(1) phase (Al4Cu9), which is only observed in alloys containing minimum of 9 mass% Al. These results may be attributed to some Ag characteristics and its interaction with Cu and Al.
10.1007-s10973-007-8551-4	4	transformation; martensite; martensitic; phase; shape; beta; memory; shape memory; temperature; temperatures; martensitic transformation; gamma; transformation temperatures; effect; thermal	The precipitation process for a concentration of CoTi of super-saturated solutions of Cu-0.50 at% Co-0.45 at% Ti (Cu-1 at% CoTi) was studied through differential scanning calorimetry (DSC) and microhardness measurements. The analysis of the calorimetric curves between the environmental temperature and 900 K shows the presence of only one exothermic reaction attributed to the formation of CoTi particles in the matrix of copper. The energy of activation estimated by using the modified Kissinger method came out much lower than the corresponding to the diffusion of the cobalt and titanium in copper. We may attribute this fact to the strong contribution of the vacancies introduced by quenching. We used the formalism of Johnson-Mehl-Avrami (JMA) to assess the kinetic parameters. The energetic and kinetic evaluations and the molar heats of precipitation obtained from the isochor of van't Hoff allow us to infer that the reaction corresponds to the formation of CoTi precipitates. The isothermal kinetics of precipitation reaction could be represented satisfactory by an overall kinetic function based in a macroscopic parameter (Vickers hardness). The kinetic parameters obtained from microhardness model are in agreements with those obtained from DSC traces.
10.1007-s10973-011-2183-4	-1		Copper has excellent thermal conductivity and is mainly applied in electrical and machinery applications. Its main disadvantage is its poor resistance in aggressive environments which can be significantly enforced by the deposition of Zinc coatings. In this study the effect of the deposition time and temperature on the thickness and microstructure of Zinc coatings on Copper substrates by pack cementation process using a DSC apparatus, is investigated. Moreover, the oxidation performance of the coated samples has been evaluated in a high-temperature environment. Oxidation tests were accomplished by thermogravimetric measurements while the coated and oxidized samples were examined with SEM microscopy and XRD diffraction analysis. DSC results revealed that the chemical reactions, which lead to the coating formation, take place up to 300 A degrees C while the coating thickness increases with the duration of the deposition process. The as formed coatings consist of two layers corresponding to different Cu-Zn phases. Finally the coated samples were found to be more resistant when exposed in the aggressive environment, as they begin to oxidize at significant higher temperatures than the uncoated samples. This can mainly attributed to the formation of ZnO on the surface of the coating.
10.1007-s10973-016-5839-2	4	transformation; martensite; martensitic; phase; shape; beta; memory; shape memory; temperature; temperatures; martensitic transformation; gamma; transformation temperatures; effect; thermal	Cu-Al-Ni shape-memory alloys are considered as high potential materials for high-temperature applications. The aim of this research was to evaluate the increasing strain value and Cr addition on martensite morphology, transformation temperatures, mechanical, and corrosion properties of Cu-Al-Ni alloy. To this purpose, thermomechanical treatment which includes successive hot rolling, annealing, and hydraulic pressing passes was applied. In addition, tensile test, differential scanning calorimetry, and potentiodynamic polarization were carried out to compare the properties of prepared samples. The results showed that by increasing the applied strain, morphological transition from wide laths to acicular martensite with monoclinic structure was occurred. The chromium element acts as a grain refiner in this alloy by restricting the grain growth . This element leads to microstructural embrittlement, diminishing the mechanical properties. Besides, the influence of applied strain and Cr content on corrosion resistance of Cu-Al-Ni alloy was reciprocal. Despite suitable effect of Cr on corrosion behavior, increasing the applied strain facilitated the corrosion rate. Another subtle point is that both Cr addition and higher strain value reduce austenite to martensite transformation temperatures and hysteresis temperature interval.
10.1007-s10973-016-5926-4	4	transformation; martensite; martensitic; phase; shape; beta; memory; shape memory; temperature; temperatures; martensitic transformation; gamma; transformation temperatures; effect; thermal	The thermally induced reversible diffusionless martensitic transformation, that governs the mechanism of shape memory alloys (SMAs), can be conveniently illustrated, on differential scanning calorimetry (DSC) curves, by a close variation loop of heat flow with temperature. Cooling-induced direct (forward) martensitic formation causes an exothermic maximum, while martensite reversion, on heating, is associated with an endothermic peak. The occurrence of diffusion-controlled phenomena is emphasized by discontinuities of heat flow variations, such as those observed in the case of Cu-Zn-Al SMAs, experiencing thermoelastic martensitic transformation. When heating such a martensitic Cu-Zn-Al SMA, four solid-state transitions were observed on DSC curves, under the form of: (1) an endothermic minimum ascribed to martensite reversion to parent phase; (2) an endothermic minimum associated with transitory formation of bainite; (3) an exothermic maximum corresponding to the precipitation of equilibrium alpha-phase and (4) an endothermic peak representing the order-disorder transition of parent phase. The first transition is diffusionless, while the other three are diffusion-controlled. The DSC equipment was used to investigate the effects of: (1) heat treatment temperature, (2) number of cycles of thermomechanical treatment and (3) thermal cycling within the temperature range where diffusion-controlled solid-state transitions occur in a Cu-Zn-Al SMA, the results being corroborated with that obtained by optical (OM) and transmission (TEM) electron microscopy.
10.1007-s10973-017-6157-z	4	transformation; martensite; martensitic; phase; shape; beta; memory; shape memory; temperature; temperatures; martensitic transformation; gamma; transformation temperatures; effect; thermal	Small amounts of Zr, as a grain refiner, were added to the beta Cu-Zn-Al shape memory alloy. The resulting microstructure was polycrystalline, with Zr-rich precipitates preferentially located in the grain boundary. An alloy of similar composition, without addition of Zr, was studied for comparison. The martensitic transformation and the stability of beta-phase were studied by differential scanning calorimetry and optical microscopy. The activation energy of phase decomposition, within the beta-phase metastability range, was determined by the Kissinger-Akahira-Sunose method, and values of 121 kJ mol(-1) for Cu-Zn-Al(Zr) and 110 kJ mol(-1) for Cu-Zn-Al were obtained. Furthermore, it was observed that the Zr-rich particles, responsible for controlling the grain size, were unstable during the heat treatments at temperatures within the beta-phase stability range. The dissolution of precipitates leads to a gradual decrease in the volume fraction of the sample that transforms to martensite. Finally, after prolonged aging the martensitic transformation disappeared.
10.1007-s10973-017-6219-2	4	transformation; martensite; martensitic; phase; shape; beta; memory; shape memory; temperature; temperatures; martensitic transformation; gamma; transformation temperatures; effect; thermal	We investigated the effect of three different quenching medias on martensitic transformation, thermodynamic parameters, phase equilibria, microstructural properties and microhardness values of high-temperature Cu-13.2Al-5.1Fe-1.2Ti (mass%) shape memory alloy by means of differential scanning calorimetry, X-ray diffraction, optical microscopy, scanning electron microscopy and Vicker's microhardness measurements. Thermal analysis indicated that the transformation temperatures and thermodynamic parameters of the alloy changed depending on quenching conditions and the transformation temperature range was proportional to the cooling rate. It was found that the step-quenching treatment improved the operation temperature of alloy. Structural analysis showed that the phase components of the alloy were not affected significantly by the quenching conditions, but elemental analysis also revealed that high cooling rate leads to very significant changes on chemical compositions of the phase components. From microstructural investigations, it was found that the microstructure of alloy included a great number of voids having different sizes and forms and also different precipitates grow in these voids. In particular, it was seen that the step-quenching process caused the formation of new voids in the microstructure. Vicker's microhardness measurements revealed that the microhardness value of the alloy was not influenced markedly by the quenching treatments.
10.1007-s10973-017-6584-x	4	transformation; martensite; martensitic; phase; shape; beta; memory; shape memory; temperature; temperatures; martensitic transformation; gamma; transformation temperatures; effect; thermal	Isothermal treatments at 413 K were performed in Cu-Al-Mn shape memory alloy samples, to study their effects on the martensitic transformation. This procedure, within the miscibility gap, produces spinodal decomposition. After each aging thermal treatment, martensitic transformation was monitored using Differential Scanning Calorimetry (DSC). Spinodal decomposition significantly changes the characteristics of the martensitic transition, reducing the transformed volume and modifying the critical temperatures. Furthermore, transformation hysteresis loop narrows as the volume fraction of the spinodal precipitates increases. Effects of thermal cycling through the martensitic transformation were studied in aged alloy samples. It was found that cycling produces critical temperatures changes, an increase in the transformed volume fraction, and a wider hysteresis loop. The observed results were discussed considering the interaction between spinodal precipitates and martensitic plates.
10.1007-s10973-018-7668-y	-1		For determination of the structure and properties of those alloys, the following investigations were carried out: scanning microscopy and EDS X-ray analysis. Investigations concerning the optimal chemical composition and production method of Cu-Ni-Si alloys modified by Cr and Re as well as the improved properties in comparison with traditional alloys contribute to better understanding of mechanisms influencing the improvement of mechanical properties of the newly developed alloys. Thermal analysis of the crystallization process allows for accurate calculation of latent heat of various phases developed during solidification. Based on the assumption that the latent crystallization heat is proportional to the share of various phases in the alloy, the thermo-derivative analysis also allows the calculation of the amount of crystallized phases. Calculation of the properties as mentioned earlier is based on the characteristic points determined in a derivative curve. The adequately selected chemical composition of the alloy, as well as the appropriate cooling rate and heat treatment conditions, leads to improvement of functional properties of manufactured elements. For the analysed alloys, a thermal derivative analysis was used to determine the kinetics of crystallization and the temperature of the beginning and the end of a phase and eutectic crystallization, mainly the liquidus temperature (TL) and solidus temperature (TSOL). The TSOL temperature determined on thermal derivative analysis is the upper limit of supersaturation of the tested alloys. The conductivity and microhardness of the tested alloys were also measured in the function of the chemical composition and the state (i.e., heat treatment).
10.1007-s10973-019-08421-3	4	transformation; martensite; martensitic; phase; shape; beta; memory; shape memory; temperature; temperatures; martensitic transformation; gamma; transformation temperatures; effect; thermal	The effect of Bi addition on precipitation and dissolution, in Cu-9at% In and Cu-5at% Sb supersaturated solid solutions, has been studied by several complementary techniques. Differential Dilatometry and Differential Scanning Calorimetry permit only the analysis of the delta phase dissolution kinetic in sufficiently aged samples. Delayed spheroidization due to Bi segregation around the precipitated lamellae, observed by Transmission Electron Microscopies in the first alloy, gives a residual interfacial energy leading to accelerated delta phase dissolution with decreased activation energy. Kinetics parameters evolution indicates a progressive delta phase continuous dissolution which makes available a small chemical driving force at high temperatures and leads to an increasing activation energy during dissolution. However, Bi dispersed particles in the second alloy haven't effect on the dissolution but they cause a contraction above 833 K. Kinetics parameters evolution indicates rapid delta phase dissolution that shifted to high temperatures where an important chemical driving force for solution treatment is available. It leads to almost constant activation energy.
10.1007-s10973-019-08452-w	4	transformation; martensite; martensitic; phase; shape; beta; memory; shape memory; temperature; temperatures; martensitic transformation; gamma; transformation temperatures; effect; thermal	The thermal behavior of the annealed Cu81Al19 alloy with Co and Zr additions was investigated using differential thermal analysis, differential scanning calorimetry, electrical resistivity measurements, optical microscopy, scanning electron microscopy, Vickers microhardness, and X-ray diffractometry. The results showed that the Co addition slightly increased the critical temperatures of melting and solidification of the Cu81Al19 alloy, suppressed the eutectoid reaction and the beta phase ordering, and introduced a new route for the alpha(2) phase disordering. A mechanism to this phenomenon is suggested in the present work. On the other hand, the Zr addition did not significantly alter the critical temperatures of melting and solidification of the Cu81Al19 alloy, decreased the intensity of the eutectoid reaction, and increased the alpha(2) phase disordering rate and the beta phase decomposition. Besides that, it introduced a new thermal event at higher temperatures, related to the dissolution of precipitates with Al. Both Zr and Co additions increased the electrical resistivity and the microhardness of the Cu81Al19 alloy due to the precipitation of intermetallic compounds.
10.1007-s10973-019-08454-8	4	transformation; martensite; martensitic; phase; shape; beta; memory; shape memory; temperature; temperatures; martensitic transformation; gamma; transformation temperatures; effect; thermal	In this study, four Cu-Al-Fe-X shape memory alloys were produced by the arc melting technique, and the martensitic transformation temperatures, thermodynamic parameters, and the activation energy values were obtained. The activation energy values of the alloys were calculated as 666.36, 401.6, 82.94, and 226.22 kJ mol(-1) for S1, S2, S3, and S4, respectively. High-temperature phase transitions and eutectoid point of the samples were examined by the differential thermal analysis method. The martensitic diffraction planes of the samples were found as 122, 0022, 1210, and 2012, and the crystallite size of the samples was calculated as 16.21, 20.20, 14.43, and 17.46, respectively. Lastly, optical micrograph observations revealed the morphology of the alloys and the variations in the grains and martensite structures. The e/a ratio of the alloys varied 1.47-1.51, and these values are in agreement with the values in literature to give shape memory effect.
10.1007-s10973-019-09234-0	4	transformation; martensite; martensitic; phase; shape; beta; memory; shape memory; temperature; temperatures; martensitic transformation; gamma; transformation temperatures; effect; thermal	We report data obtained from the spinodal decomposition in samples of two compositions of intermetallic Cu-Al-Mn shape memory alloys. Detailed experimental information has been collected by means of differential scanning calorimetry (DSC). Spinodal decomposition was induced by isothermal treatments at different temperatures within the miscibility gap. To determine the precipitation kinetics, after each isothermal treatment particle dissolution curves were obtained by DSC. From the dissolution curves, various aspects of the precipitation process were determined, such as particles dissolution enthalpy; initial precipitate volume fraction evolution; non-isothermal dissolution characteristics; dissolution activation energy and particle distribution information. Regardless of the composition, the determined activation energy was 77 kJ mol(-1). Diffusion of Mn atoms seems to be the fundamental factor that controls the studied processes.
10.1007-s10973-020-10002-8	4	transformation; martensite; martensitic; phase; shape; beta; memory; shape memory; temperature; temperatures; martensitic transformation; gamma; transformation temperatures; effect; thermal	In this study, the effects of Zr additions on the thermal behavior of the Cu-9Al-10Mn-3Ag, Cu-9Al-10Mn-3Ag-7Zr, and Cu-9Al-10Mn-3Ag-9Zr alloys were evaluated using differential scanning calorimetry, differential thermal analysis, optical micrographs, scanning electron micrographs, microhardness, magnetization as a function of the applied field. The additions of Zr were associated with decreasing in alpha-phase grain size, changes in saturation magnetization, and with the formation of a new phase in the alloy containing 9 mass% of Zr. In addition, there was an alteration in the mechanism of the Cu2AlMn phase dissolution in the Cu-9Al-10Mn-3Ag-9Zr alloy.
10.1007-s10973-020-10128-9	-1		The thermal behavior of two copper alloys, with 0.2 and 0.5 mass % of Mg, was analyzed after severe plastic deformation processing by Equal Channel Angular Pressing (ECAP). Both alloys were forced to be passed through a 90o inner angle ECAP die at room temperature up to 16 passes following route Bc. The thermal stability was analyzed in terms of the recrystallization kinetics by using the Various Heating Rates method, derived from the Johnson-Mehl-Avrami-Kolmogorov equation, after analyzing the Differential Scanning Calorimetry peaks for both alloys at any pass of ECAP. The calculated recrystallization parameters included the activation energies (E(kJ mol(-1))E-CuMg02 = 42.6 +/- 19.8E(CuMg05) = 52.7 +/- 13 kJ mol(-1)) and the kinetic exponentnwhich took an average value of approximate to 1.75, irrespective of the considered alloy.
10.1007-s10973-022-11860-0	4	transformation; martensite; martensitic; phase; shape; beta; memory; shape memory; temperature; temperatures; martensitic transformation; gamma; transformation temperatures; effect; thermal	CuAlMn alloys are very interesting materials because they have several types of phase transformations, which depend on the Mn and Al concentrations and also on heat treatments. In this study, the effects of Mn additions on the thermal behavior of hypoeutectoid Cu81-xAl19Mnx alloys were investigated using differential scanning calorimetry, differential thermal analysis, X-ray diffractometry, optical microscopy, scanning electron microscopy, X-ray energy-dispersive spectroscopy, and magnetization measurements as a function of the applied field. The samples were analyzed after slow cooling at 1.0 K min(-1), and the results showed that the mixing enthalpy alters the melting range of the studied alloys. The cooling rate was not sufficient to completely decompose the beta phase in the Cu81Al19 alloy. The Mn concentration limit for the appearance of considerable magnetic effects in Cu81-xAl19Mnx alloys is around 4 at%. The results indicated that the manganese is more effective in the decrease in reaction rates involving phases produced from the beta(A2) structure.
10.1007-s10973-022-11875-7	-1		Bulk metallic glass of Cu38Zr54Al8 nominal composition was synthesized by copper mold casting into 6 mm diameter rods. Disks of the as-cast glass were subjected to severe plastic deformation by high-pressure torsion for different number of revolutions. The microstructure and the thermal behavior of the as-cast, isothermally annealed and deformed glass have been investigated by X-ray diffraction and differential scanning calorimetry, respectively. Continuous heating experiments revealed a two-stage devitrification event with excellent glass forming parameters, such as glass transition (T-g = 671 K), supercooled liquid region ( increment T-x = 80 K), reduced glass transition (T-r = 0.57) and gamma parameter (gamma = 0.41). Power law crystal growth during diffusion-controlled homogeneous nucleation was observed for isothermal annealings. Glassy state was preserved almost in the entire sample volume of the as-cast alloy during the high-pressure torsion process, corresponding to the extreme stability of the Cu38Zr54Al8 alloy against deformation-induced devitrification. This is in accordance with the transition of the reversible specific heat from the glassy to supercooled liquid state measured by modulated calorimetry. It was also concluded that glassy structure is more ordered in the severely deformed state.
10.1007-s10973-022-11918-z	4	transformation; martensite; martensitic; phase; shape; beta; memory; shape memory; temperature; temperatures; martensitic transformation; gamma; transformation temperatures; effect; thermal	Effects of Sn and Gd additions on the (beta(1) + beta(3)) field in the Cu-11%Al-10%Mn alloy were studied by in situ X-ray diffraction, differential scanning calorimetry, non-isothermal kinetics, and magnetization measurements as a function of the temperature. The microstructures were investigated using optical microscopy and scanning electron microscopy coupled with energy dispersive X-ray spectroscopy. The results showed that the beta(3) (Cu2AlMn) + beta(1) (Cu3Al) -> beta(3) (Cu2AlMn) reaction is strongly dependent on the heating and cooling rates. The Sn addition to the Cu-11%Al-10%Mn alloy stabilizes the ferromagnetic beta(3) phase. In the Sn-containing alloy, the miscibility gap transition is followed by the martensitic transformation at about 560 K. Both Sn and Gd additions have extended the stability field of the ferromagnetic beta(3) phase. Nonetheless, the formation of Cu5Gd precipitates slows the miscibility gap transition on heating, which may be associated with the reduction of the ferromagnetic phase amount at room temperature in the Cu11%Al10%Mn3%Gd alloy.
10.1007-s10973-023-12822-w	4	transformation; martensite; martensitic; phase; shape; beta; memory; shape memory; temperature; temperatures; martensitic transformation; gamma; transformation temperatures; effect; thermal	In this study, Cu-13.5Al-4Ni shape memory alloy (mass %) was tested. The alloy samples, at different pressures, were aged for an equal period of 5 min. The physical properties of Cu-13.5Al-4Ni alloy samples aged for an equal period were investigated. Differential scanning calorimetry (DSC) was used to investigate the impact on thermodynamic parameters. The differential thermal analysis (TG/DTA) measurements were made to obtain the ordered-disordered phase transformations from room temperature to 1200 degrees C. X-ray diffraction (XRD) and optic microscope observation were used to examine the microstructure. Microhardness measurements were performed on alloy samples aged for an equal period. The physical properties of the samples aged at different pressures for an equal period were compared to the measurement results of the homogenous sample.
10.1007-s10973-024-13259-5	-1		Cu-Al-Fe shape memory alloys are a new kind of smart materials with high phase transition temperature. However, poor thermal stability and poor shape memory effect limit the commercial application range. In this paper, the effect of Al content on microstructure, thermal stability, shape memory effect and mechanical properties of Cu-Al-Fe shape memory alloys was investigated systematically by changing Al content, so as to obtain the optimal composition ratio for better commercial application. The results show that in the as-cast state, the microstructure is a mixture of (Cu) phase, beta ' martensite and Fe(Cu, Al) phase with Al content of 11 mass%, and a mixture of beta ' martensite and Fe(Cu, Al) phase with Al content of 12 mass% and 13 mass%. After quenching, beta ' martensite exists in all alloys, while (Cu) phase and Fe(Cu, Al) phase disappear, and gamma ' martensite also exists at Al content of 13 mass%. The shape memory alloy effect of as-cast alloy is enhanced with the increase of Al content, while the shape memory effect of quenched alloy increases first and then decreases. Among them, Cu82Al13Fe5 has the best shape memory effect, the recovery ratio reaches 84.38%, and it also has the best thermal stability.
10.1007-s10973-025-14037-7	14	strength; properties; conductivity; electrical; mechanical; cu-; grain; mpa; electrical conductivity; aging; precipitation; phase; mechanical properties; tensile; phases	This study investigates the effects of heat treatment on the properties of Cu-Al-Ni shape memory alloy (SMA). The Cu-Al-Ni alloy was synthesized using an induction melting furnace, and followed by quenching (hardening) at three different temperatures (673 K, 873 K, and 1073 K) using an electrical furnace for an hour. The effects of heat treatment on thermal properties, transformation temperatures, crystal structure, microhardness, and microstructure, were analyzed using differential scanning calorimetry (DSC), X-ray diffraction (XRD), Vickers hardness tests, and scanning electron microscopy (SEM). Results indicated that heat treatment increased transformation temperatures and enhanced thermal stability, with changes in enthalpy and entropy. XRD analysis revealed a reduction in phase intensity and grain size with increasing treatment temperature, correlating with increased hardness due to grain boundary effects. SEM micrographs confirmed the presence of the martensite phase at room temperature. These findings demonstrate that heat treatment improves the material's performance, making it more suitable for high-temperature applications in industries such as aerospace and automotive.
10.1007-s11015-025-01920-9	-1		We study specific features of solidification of cylindrical ingots with a diameter of 50 mm produced of copper-phosphorus alloys by continuous upward casting and intended for the hot extrusion of wire braze-alloy billets. The advantages and disadvantages of the procedure of continuous upward casting as applied to copper alloys are presented. We studied ingots of two alloys, namely, Cu-7.2%P and Cu-8.2%P. The Cu-7.2%P alloy proves to be the most common two-component braze alloy for high-temperature brazing of copper and copper alloys. The Cu-7.2%P alloy is eutectic and, hence, not suitable for brazing. We studied defects of ingots in the form of concentrated central cavities with wavy surfaces. It is shown that the formation of defects of this kind is possible only for the indicated type of continuous casting when the direction of ingot drawing is opposite to the direction of gravity. The mechanism of formation of the internal wavy surface of these defects is clarified. To prevent the appearance of these defects, it is necessary to create conditions under which the process of solidification of the ingot is completed below the level of the melt in the furnace. The structures of ingots were analyzed both in the longitudinal sections and in cross sections. It is shown that the macrostructure of the ingots of Cu-8.2%P alloy is columnar. The phenomenon of spontaneous formation of the profile lines of solidification front in metallographic sections of the ingots of Cu-8.2%P alloy was discovered. The formation of these lines is caused by two factors: the mode of step-by-step drawing and the nature of the alloy. The mode of step-by-step drawing leads to changes in the solidification conditions of the eutectic phases in the course of motion and during the shutdown. Specific features of solidification of the eutectic phases of copper-phosphorus alloys contribute to the formation of their different morphologies in the case where the solidification conditions are modified. The results of measuring of the sizes of dendrite cells in different parts of cross section of the ingot of Cu-8.2%P alloy enable us to make a conclusion about the similar nature of solidification of the ingot of this alloy and an ingot of Cu-8.2%P alloy under the identical casting conditions.
10.1007-s11041-007-0022-9	-1		The strain behavior and phase transformations in Cu-37 wt% Zn brass, Cu-12.5 wt% Al bronze, and copper (99.97%) are studied under two variants of pulse loading, i.e., converging shock waves and a flux of powder particles accelerated by explosion. The effects connected with uniform and localized strain caused by the action of shock waves are determined and the disperse structures formed in the materials under dynamic loading are analyzed.
10.1007-s11041-007-0032-7	-1		Microstructure and resistivity of ribbons from melt-spun CuCrTi alloys are studied in the initial state and after annealing. Lattice periods of the copper matrix and of chromium inclusions are determined. Thermodynamic analysis of processes occurring in solidification of the alloys is performed.
10.1007-s11041-007-0043-4	4	transformation; martensite; martensitic; phase; shape; beta; memory; shape memory; temperature; temperatures; martensitic transformation; gamma; transformation temperatures; effect; thermal	Ways for changing the structure and properties of alloys of the Cu-Zn-Fe-Mn-Si system due to formation of required amount of CuZn ordered beta-phase with specific grain size during heat treatment and for raising the endurance of alloys of the Fe-Cr-Al system due to formation of ordered DO3- or B2-phases in the alpha-solid solution during aluminizing are considered. The effect of the composition of alumosilicide beta-coatings on their protective properties is analyzed, including their resistance to cracking upon rapid cooling. The effect of boron on the endurance of such coatings is studied.
10.1007-s11041-011-9364-4	16	wear; composite; composites; powders; milling; particles; powder; wt; sliding; friction; hardness; matrix; mechanical; surface; properties	The microstructure and microhardness of ingots from Cu-V and Cu-V-Fe alloys obtained by three melting methods, i.e., induction melting and electric arc melting with consumable and nonconsumable electrodes, are studied. The microstructures of the ingots are compared.
10.1007-s11041-011-9380-4	4	transformation; martensite; martensitic; phase; shape; beta; memory; shape memory; temperature; temperatures; martensitic transformation; gamma; transformation temperatures; effect; thermal	The phases obtained in copper aluminum bronze alloy (Cu-10 wt% Al-2 wt% Fe) cast into a permanent die were investigated. The parameters examined were the preheating temperatures of the die and the graphite coating thickness. The phases alpha and gamma(2) were detected as well as the metastable phases beta' and gamma'. The intermetallics of the system Fe-Al were obtained in various stoichiometric compositions. The different cooling rates of the casting resulted in two mechanisms of transformation to alpha grains out of the unstable beta phase, one being nucleation and growth producing needle-shaped alpha grains, the other exhibiting a massive transformation to spherical alpha grains. These two mechanisms determine the changes in the size of the alpha grains as a result of changes in the cooling rate in its various ranges.
10.1007-s11041-017-0086-0	4	transformation; martensite; martensitic; phase; shape; beta; memory; shape memory; temperature; temperatures; martensitic transformation; gamma; transformation temperatures; effect; thermal	The effect of deformation on the damping capacity of a copper-base shape memory alloy produced by standard methods is studied. The metallographic analysis is performed with the help of scanning electron microscopy. The internal friction is measured at different temperatures. The damping capacity of the alloy is analyzed and its relation to the mechanical and physical properties is determined.
10.1007-s11041-020-00567-4	-1		The kinetics of formation of precipitates in a Cu-2% Be alloy is studied in terms of the Avrami and Orowan equations.We determine the structure and hardness of the alloy after aging at 260-440 degrees C for 0.25-10 h and compute the activation energy of precipitates.
10.1007-s11051-012-1124-x	-1		Bimetallic clusters display new characteristics that could not be obtained by varying either the size of pure metallic systems or the composition of bulk bimetals alone. Coating of pre-deposited clusters by vapour deposition is a typical synthesis process of bimetallic clusters. Here, we have demonstrated that hierarchical, gold cluster-decorated copper clusters as well as both heterogeneous and homogeneous Cu-Au bimetallic clusters (4.6 to 10.7 nm) can be prepared by coating pre-deposited, size-selected Cu-5000 (4.6 +/- 0.2 nm) with Au evaporation at various temperatures. These bimetallic clusters were analyzed by aberration-corrected scanning transmission electron microscopy and associated electron energy loss spectroscopy. The results indicate that the growth of bimetallic clusters is controlled by a competition between nucleation and diffusion of the coating Au atoms.
10.1007-s11051-020-04793-y	-1		Zirconia nanoparticle-reinforced copper matrix composites were successfully fabricated using an in situ oxidation technique with liquid Cu-Zr alloy. Cu-1 wt% Zr alloy was oxidized at liquidus temperature under an oxygen potential-controlled N-2 atmosphere to yield 2.2 vol% ZrO2 particles ranging from 1 to 20 nm. TEM observation showed a semi-coherent relationship between the dispersoids (monoclinic zirconia) and Cu matrix, with uniform distribution in the Cu-ZrO2 composite. The formation of fine ZrO2 particles in the copper matrix composite was related to the selective oxidation of Zr and isothermal solidification of Cu at the liquidus temperature of the Cu-Zr alloy. A possible formation mechanism for the ZrO2 particles based on oxygen diffusion is proposed; in this model, O atom diffusion is hindered by the formation of a Cu shell on the ZrO2 particles, thereby inhibiting ZrO2 particle growth . The microhardness of the Cu-2.2 vol% ZrO2 composite was 91 HV and the maximum value of electrical conductivity was 93% IACS.
10.1007-s11051-022-05511-6	6	grain; deformation; strain; strength; dislocation; cu-; tensile; size; ecap; grain size; sfe; ductility; hardening; high; stress	Utilizing molecular dynamics (MD) simulation, the effects of grain size and twin boundary spacings (TBS) on the deformation mechanisms of nano-twinned (NT) Ag-doped Cu alloys are investigated. The doped Ag atoms are segregated to grain boundary affect zone (GBAZ). Both lattice and twining partial dislocations emitted from the amorphous inter-granular layer (GBAZ-segregated domains) are frequently observed, which switch on the strength enhancement and strength softening regime respectively. Consequently, it is hard to relate flow stress with dislocation density. Fortunately, the average flow stress of NT Ag-doped Cu alloy seems to be sensitive to GBAZ phase transition rather than dislocation density.
10.1007-s11085-004-7804-x	-1		The oxidation behavior of Glidcop AL-15 (Cu-O.3 wt% Al2O3), an ODS copper alloy of interest for aerospace structural application, was investigated by oxidation and two-step oxidation in a TGA. The results were compared with the oxidation kinetics of pure Cu and two other aerospace Cu alloys, GRCop-84 (Cu-8Cr-4Nb) and NARloy-Z (Cu-3 Ag-O.5Zr). AL-15 exhibited the lowest oxidation rate from 500 to 650degreesC. The superiority in oxidation resistance is thought to result from the Al2O3, and the two-step oxidation results suggest the Al2O3 dissolves in the oxide scale, perhaps creating charge and stress fields that suppress oxidation by retarding the Cu diffusion rate.
10.1007-s11085-005-4393-2	-1		A new method is described for the simple and straight-forward evaluation of a materials resistance to blanching, a mode of degradation that limits the life and performance of rocket engine thrust-cell liners. The method is based on cyclic exposure to oxidation and reduction with continuous monitoring of weight changes. Results obtained so far are in excellent agreement with known and expected blanching behavior of available Cu alloys, showing that this method provides an effective screening test for blanching susceptibility.
10.1007-s11085-006-9012-3	-1		The oxidation of three Cu-xCr-2Al and three Cu-xCr-4Al alloys (x congruent to 0,4,8 at%) has been investigated at 800 degrees C in 1 atm O-2. Oxidation of a binary Cu-Al alloy containing 2.2 at% Al produced external scales composed mainly of copper oxides with small amounts of Al-rich oxide in the inner region, while the internal oxidation of Al was almost absent. The addition of 3.9 at% Cr to this alloy was able to decrease the oxidation rate but was insufficient to prevent the oxidation of copper. Conversely, addition of 8.1 at% Cr to the same binary alloy promoted the rather fast formation of a protective Al2O3 layer in contact with the metal substrate, with a simultaneous large decrease in the oxidation rate, producing a form of third-element effect. On the contrary, all the Cu-xCr-4Al alloys formed an internal Al2O3 layer after an initial stage during which all the alloy components were oxidized, so that the only effect of the presence of chromium was to decrease the duration of the fast initial stage. The third-element effect due to chromium additions to Cu-2Al is related to a transition from the formation of external scales composed of mixtures of Cu and Al oxides to the external growth of Al2O3-rich scales as a consequence of a thermodynamic destabilization of copper oxides associated with the formation of solid solutions between Al2O3 and Cr2O3.
10.1007-s11085-006-9017-y	-1		The poor oxidation resistance of Cu-base alloys limits their applications at high temperatures, and it cannot be improved by conventional Cr alloying because that requires an extremely high Cr content. In this work a chromia scale has been formed on novel Cu-base nanocomposites which contain much less chromium. Cu-Ni-Cr nanocomposites, with the weight percentage ratio of Cu/Ni approximate to 1 and various amounts of Cr, were produced by co-electrodeposition of Cu-Ni alloy with Cr nanoparticles which subsequently acted as seeds for chromia formation. The results of oxidation tests in air at 800 degrees C showed that only 15 wt% Cr in the nanocomposite was required to form an external chromia scale. Furthermore, the scale consisted only of chromia rather than the duplex scales which form on the conventional alloy even when it contains significantly more chromium.
10.1007-s11085-007-9068-8	-1		The oxidation behavior of a Cu60Hf25Ti15 bulk metallic glass was studied over the temperature range of 375-520 degrees C in dry air. The oxidation kinetics of the amorphous alloy generally followed the parabolic law at all temperatures, with an oxidation rate increasing with temperature. The oxidation rates of the amorphous alloy were much higher than those of polycrystalline pure-Cu, implying that the additions of Hf and Ti accelerated the oxidation reaction. The composition of the scales formed on the amorphous alloy was strongly temperature-dependent, since they consisted mostly of Cu4O3 and CuO with minor amounts of HfO2 at T <= 450 degrees C, while mostly CuO with minor amounts of HfO2 and Cu2TiO3 were detected at higher temperatures. In addition, nanocrystalline Cu51Hf14 and Cu3Ti2 phases were detected on the substrate after oxidation at T >= 450 degrees C, indicating the occurrence of phase transformation.
10.1007-s11085-008-9098-x	-1		Oxidation of five Cu-Zn alloys at 1,073 K in 0.1 MPa O-2 showed the existence of three possible oxidation modes, including the internal oxidation of zinc beneath external CuOx scales, the growth of mixtures of the two oxides and the exclusive growth of external ZnO scales. The critical Zn contents required for the transitions between these oxidation modes have been calculated and compared with the experimental results.
10.1007-s11085-008-9104-3	-1		The isothermal oxidation kinetics of as-cast Cu-17%Cr and Cu-17%Cr-5%Al in air were studied between 773 and 1,173 K under atmospheric pressure. Details of the oxidation kinetics of these alloys were discussed in Part I. This paper analyzes the microstructures of the scale and its composition in an attempt to elucidate the oxidation mechanisms in these alloys. The scales formed on Cu-17%Cr specimens oxidized between 773 and 973 K consisted of external CuO and subsurface Cu(2)O layers. The total thickness of these scales varied from about 10 mu m at 773 K to about 450 mu m at 973 K. In contrast, thin scales formed on Cu-17%Cr-5%Al alloys oxidized between 773 and 1,173 K. The exact nature of these scales could not be determined by X-ray diffraction but energy dispersive spectroscopy analyses were used to construct a scale composition map. Phenomenological oxidation mechanisms are proposed for the two alloys.
10.1007-s11085-008-9110-5	-1		The isothermal oxidation kinetics of as-cast Cu-17%Cr and Cu-17%Cr-5%Al in air were studied between 773 and 1,173 K under atmospheric pressure. These observations reveal that Cu-17%Cr-5%Al oxidizes at significantly slower rates than Cu-17%Cr. The rate constants for the alloys were determined from generalized analyses of the data without an a priori assumption of the nature of the oxidation kinetics. Detailed analyses of the isothermal thermogravimetric weight change data revealed that Cu-17%Cr exhibited parabolic oxidation kinetics with an activation energy of 165.9 +/- 9.5 kJ/mol. In contrast, the oxidation kinetics for the Cu-17%Cr-5%Al alloy exhibited a parabolic oxidation kinetics during the initial stages followed by a quartic relationship in the later stages of oxidation. Alternatively, the oxidation behavior of Cu-17%Cr-5%Al could be better represented by a logarithmic relationship. The parabolic rate constants and activation energy data for the two alloys are compared with literature data to gain insights on the nature of the oxidation mechanisms dominant in these alloys.
10.1007-s11085-008-9128-8	-1		Four ternary Cu-Zn-Al alloys containing 5 or 10 at% Zn and 2 or 4 at% Al plus an alloy containing 2 at% Al and 15 at% Zn have been oxidized at 800 A degrees C in 1 atm O-2, and their behavior has been compared with that of the corresponding binary Cu-Zn and Cu-Al alloys. For the alloy containing 4 at% Al, which is already able to form external alumina scales, the addition of Zn is only effective in reducing the mass gain during the fast, initial-oxidation stage. Conversely, the addition of 15 at% Zn to Cu-2Al is able to prevent the formation of external scales containing mixtures of the Cu and Al oxides, resulting in the formation of external alumina scales after an initial stage of faster rate, producing a limited third-element effect. Finally, the addition of Al to both Cu-5Zn and Cu-10Zn is able to prevent the internal oxidation of Zn, producing a kind of reversed third-element effect. Possible mechanisms for these effects are examined on the basis of general treatments concerning the scaling behavior of ternary alloys.
10.1007-s11085-012-9332-4	-1		The transient oxidation stage of a model metal alloy thin film was characterized with in situ ultra-high vacuum (UHV) transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS) and analytical high-resolution TEM. We observed the formations of nanosized NiO and Cu2O islands when Cu-5at%Ni(001) was exposed to oxygen partial pressure, and various temperatures in situ. At 350 A degrees C epitaxial Cu2O islands formed initially and then NiO islands appeared on the surface of the Cu2O island, whereas at 550 A degrees C NiO appeared first. XPS and TEM revealed a sequential formation of NiO and then Cu2O islands at 550 A degrees C. The temperature-dependent oxide selection may be due to an increase of the diffusivity of Ni in Cu with increasing temperature.
10.1007-s11085-017-9793-6	-1		The high-temperature oxidation resistance of Cu-Te-Se alloys and Cu-Se alloys at 300, 400, 500 and 600 A degrees C was studied by measuring weight gain per unit area after fixed oxidation times. The morphologies of the oxide scales formed were observed using a scanning electron microscope, with the distribution of element detected by an energy-dispersive spectrometer, and the phases identified using X-ray diffraction. The focus of this study was to understand the effects of tellurium (Te) and selenium (Se) additions on the high-temperature oxidation resistance of copper alloys. At the dilute levels studied (<= 0.5 wt% total), these elements underwent internal oxidation. Meanwhile, new phases formed, which made oxidation films more compact and increased the adherence between the oxide film and the alloy matrix, as well as prevented oxygen diffusing in the copper alloy matrix, so the oxidation resistance of copper alloys was improved.
10.1007-s11090-018-9880-8	-1		The paper presents experimental results of a new method of production of nanoparticles of copper-nickel alloys from the reduction of the mixture of cupric oxide (CuO) and nickel oxide (NiO) by low-temperature hydrogen plasma in a microwave assisted hydrogen plasma set-up. The microwave power and hydrogen flow-rate used for the current investigation are 750 W and 2.5 x 10(-6) m(3) s(-1) respectively. The addition of NiO-CuO, in proportion to result in alloys of 90Cu:10Ni and 70Cu:30Ni, not only removed the induction period from the kinetic plot of CuO reduction but also, improved the reduction rate of CuO. The XRD analysis of the product exhibited a single-phase peak with a d-spacing lying between Cu and Ni, which satisfies the Vergard's law, indicating the Cu-Ni alloy formation. The lattice parameter decreases from 3.6221 (90Cu:10Ni) to 3.595 C (70Cu:30Ni), due to the smaller atomic radius of Ni (0.1246 nm) than that of Cu (0.1278 nm). The crystallite size, calculated by applying Scherrer's formula, in both cases is found to be 31.7 nm.
10.1007-s11106-005-0081-7	-1		Effects have been established for phosphorus and lead on the working characteristics of tinned bronze with high-speed operation (up to 20000 rpm or up to 2 m/sec) at low pressures (up to 2.0 MPa). It has been found that Cu-Sn-Pb-CP powder bearing material, where CP is a copper-phosphorus alloy, under such conditions has a lower coefficient of friction than does tinned bronze and a much higher wear resistance, while sliding bearings based on it have high working life. A microheterogeneous structure is formed in this material: an a-solid solution of tin in copper, along the boundaries of which there is uniformly distributed a strengthening phase (network of copper phosphide Cu3P with inclusions of the phosphide eutectic Cu3P + Cu3Sn + (Cu-Sn), and there are lead inclusions at the grain boundaries intersections. This material has very good tribotechnical characteristics at high rotation speeds and low pressures and also low coefficient of friction, low wear, and consequently long working life of bearings made of it.
10.1007-s11106-007-0013-9	12	thermodynamic; ternary; phase; data; experimental; equilibria; phase equilibria; liquid; binary; experimental data; calculated; phases; literature; model; calphad	The mixing enthalpies and activities of components in liquid and solid alloys as well as the parameters of stable and metastable ti-an formations are used for the thermodynamic evaluation of the Cu-Co system within the CALPHAD approach . The thermodynamic parameter for the (epsilon Co) phase is evaluated within the Miedema model. The thermodynamic model of the system provides a self-consistent description of all thermodynamic quantities and phase transformations, including metastable ones. The description is in close agreement with experimental data. The thermodynamic model of system is used to explain the extension of the concentration range of supersaturated fcc solutions prepared by melt quenching.
10.1007-s11106-007-0073-x	12	thermodynamic; ternary; phase; data; experimental; equilibria; phase equilibria; liquid; binary; experimental data; calculated; phases; literature; model; calphad	Thermodynamic evaluation of the Cu-Ni system within the CALPHAD approach is based on values of mixing enthalpies and activities of components in liquid and solid solutions, as well as parameters of phase transformations. The excess Gibbs free energy of phases is described by the following equations: Delta G(L, ex) = x(Ni)(1-x(Ni))(14259 + 0.45T) J/mole for liquid alloy and Delta G((Cu, Ni), ex) = x(Ni)(1-x(Ni)) x (6877.12 + 4.6T + (1-2x(Ni))(-2450.1 + 1.87T)) J/mole for fcc solution. For the Gibbs free energy of the (Cu, Ni) phase, the magnetic effect is described by thye Hillert-Jarl method. The thermodynamic model of the system generates a self-consistent description of all thermodynamic values and phase equilibria. The calculated binodale of fcc solid solution is in satisfactory agreement with experimental data. The critical point have coordinates 605 K and x(Ni) = 0.6
10.1007-s11106-008-9008-4	12	thermodynamic; ternary; phase; data; experimental; equilibria; phase equilibria; liquid; binary; experimental data; calculated; phases; literature; model; calphad	The thermodynamic properties of phases and phase equilibria in the Cu-Hf system are described with the CALPHAD method. The set of self-consistent model parameters is based on the thermodynamic properties of liquid alloys, intermetallic compounds, and phase equilibria. The excess Gibbs energy of the liquid phase is described using an ideal associated solution model. The models of thermodynamic properties are used to describe possible metastable transformations such as glass formation in rapid quenching from the melt, formation of bulk amorphous alloys, and formation of supersaturated terminal solid solutions.
10.1007-s11106-008-9026-2	12	thermodynamic; ternary; phase; data; experimental; equilibria; phase equilibria; liquid; binary; experimental data; calculated; phases; literature; model; calphad	The CALPHAD method is used for the thermodynamic assessment of the Cu-Ti system that bounds the ternary Cu-Ti-Zr system, which is capable of forming amorphous alloys. The self-consistent parameters of thermodynamic models of the phases are obtained from data on the phase equilibria and thermodynamic properties of liquid alloys and intermetallic compounds. The Gibbs energy of the liquid phase is described using the associated ideal solution model. To describe the thermodynamic properties of the Cu4Ti and CuTi intermetallic compounds with homogeneity range, sublattice models are used. The calculated phase diagram of the system and the thermodynamic properties of the phases are in good agreement with experimental data.
10.1007-s11106-008-9039-x	12	thermodynamic; ternary; phase; data; experimental; equilibria; phase equilibria; liquid; binary; experimental data; calculated; phases; literature; model; calphad	The thermodynamic assessment of the Cu-Zr and Ti-Zr systems is carried out using the CALPHAD method. The Gibbs energy of Cu-Zr liquid alloys is described by the ideal associated solution model. The excess Gibbs energy of Ti-Zr liquid alloys and Cu-Zr and Ti-Zr solid solutions is descried by models with Redlich-Kister polynomials. The Gibbs energy of Cu-Zr intermetallic compounds is described by models taking into account their formation enthalpy and entropy. A set of self-consistent parameters of the models is obtained using data on phase equilibria and thermodynamic properties of the phases. The calculated phase diagrams of the systems and values of thermodynamic properties of the phases are in good agreement with experimental information. The relative thermodynamic stability of supercooled liquid alloys and competitive crystal phases of the Cu-Zr system are analyzed.
10.1007-s11106-008-9062-y	12	thermodynamic; ternary; phase; data; experimental; equilibria; phase equilibria; liquid; binary; experimental data; calculated; phases; literature; model; calphad	The thermodynamic assessment of the Cu-Ti-Zr system is carried out in the framework of the CALPHAD method. The Gibbs energy of the liquid alloys is described by the ideal associated solution model. The excess Gibbs energy of the solid solutions is described using the Redlich-Kister-Muggianu model. The Gibbs energy of intermetallic compounds with homogeneity region is described in the framework of the Compound Energy Formalism. A set of self-consistent parameters of models is obtained taking into account data on phase equilibria and thermodynamic properties of the liquid phase. The calculated isothermal and vertical sections of the phase diagram and liquidus and solidus surfaces are in satisfactory agreement with corresponding experimental data. Metastable transformations with participation of the supercooled liquid melts are calculated. Predicted concentration ranges of amorphization are in satisfactory agreement with experimental data.
10.1007-s11106-017-9890-8	12	thermodynamic; ternary; phase; data; experimental; equilibria; phase equilibria; liquid; binary; experimental data; calculated; phases; literature; model; calphad	The partial mixing enthalpies of titanium, zirconium, and hafnium with liquid copper and iron alloys are studied by high-temperature calorimetry. The studies are carried out at a temperature of 1873 K along the sections with constant ratios x (Cu)/x (Fe) = 3, 1, and 1/3. Along all the studied sections, these functions are negative. The integral mixing enthalpies of components in the Cu-Fe-(Ti, Zr, Hf) systems along the studied sections are calculated by integrating the Gibbs-Duhem equation. The Delta H functions for ternary Cu-Fe-(Ti, Zr, Hf) melts are characterized by positive values in the vicinity of the binary Cu-Fe system and show negative values in a range of compositions with x (Me) > 0.1 (Me = = Ti, Zr, Hf).
10.1007-s11106-018-9989-6	12	thermodynamic; ternary; phase; data; experimental; equilibria; phase equilibria; liquid; binary; experimental data; calculated; phases; literature; model; calphad	The partial enthalpies of mixing of titanium and hafnium in liquid Cu-Hf-Ti alloys were investigated at 1873 K along the x(Cu)/x(Hf) = 3 (at x(Ti) = 0-0.25) and x(Cu)/x(Ti) = 3 (at x(Hf) = 0-0.5) sections by a hightemperature isoperibolic calorimeter. The limiting partial enthalpy of mixing of supercooled liquid titanium in liquid Cu-Hf alloy is 2.0 +/- 1.5 kJ/mol. The limiting partial enthalpy of mixing of supercooled liquid hafnium in liquid Cu-Ti alloy is -43.0 +/- 4.5 kJ/mol. The integral mixing enthalpies of components along the investigated sections are calculated by integrating the Gibbs-Duhem equation. The integral mixing enthalpy is negative in the investigated composition range. The comparison of our experimental results with the calculations according to Miedema's model shows that this model's prediction for the H-mix function should be treated with caution.
10.1007-s11106-020-00122-z	-1		The influence of minor solute additions of Sn on hardening behavior and microstructure evolution of the Cu-Cr-Sn alloys has been investigated with help of an optical microscope, scanning electron microscope, transmission electron microscopy, and the Vickers hardness tester. Experimental results show that the Sn solutes, homogeneously distributed within the Cu matrix, provide a weak solid solution strengthening effect in the Cu-Cr-Sn alloy, nevertheless are important in enhancing precipitation hardening. The Cu-0.43Cr-0.36Sn alloy exhibits a significant age-hardening effect with a hardness increase by 62 HV after peak aging at 450 degrees C, which is stronger than that of the Cu-0.43Cr-0.08Sn and the Cu-0.43Cr-0.17Zr-0.05Mg-0.1RE alloys. A trace amount of Sn is highly effective at suppressing the transformation of the Cr-rich phase from the face-centered cubic (FCC) into the body-centered cubic (BCC) structure in the Cu-Cr alloys during the aging process, and therefore the FCC Cr-rich precipitate is the dominant strengthening phase in the Cu-Cr-Sn alloys. Besides, a higher areal number density of Cr-rich precipitates (4.2 center dot 10(15) m(-2)) was observed in peak-aging Cu-0.43Cr-0.36Sn alloy as compared to Cu-0.43Cr-0.08Sn alloy, which shows that the adding Sn to Cu-Cr alloy can accelerate the nucleation of the Cr-rich precipitates. The improvement of precipitation hardening and hardening kinetics in the Cu-0.43Cr-0.36Sn alloy is mainly attributed to the acceleration in the nucleation of Cr-rich precipitates through Sn addition.
10.1007-s11106-021-00226-0	-1		New Cu-Mo composite materials were produced by physical vapor deposition (PVD) using an L5 electron-beam unit. They were proposed as an alternative to silver-containing materials for the manufacture of electrical contacts. The electrical (resistivity), mechanical (hardness, shear strength), and chemical (oxidation resistance in long-term operation at high currents and temperatures, welding resistance of contact systems at peak loads) properties of the PVD Cu-Mo composites were studied against the properties of serial electrical contact materials manufactured from AgC5 and Ag-CdO pseudoalloys. The developed materials were found to be competitive with silver-based composites in terms of output resistivity and welding resistance of contact systems at currents up to 3000 A, exceeding the rated values by more than 10 times. The resistivity increased by two to three times, but no signs of seizure (welding) were found on any contact. The brazed joint with a contact copper support for the Cu-Mo alloys showed more than two times greater strength and four times greater hardness than that for the AgC5 alloys. At the same time, the developed copper-based alloys were inferior to the silver-based alloys in oxidation resistance, in turn leading to greater resistivity and heating of the contacts. The corrosion resistance of the Cu-Mo alloys strongly depends on the presence of droplet inclusions (with corrosion processes being intensified around them), operating environment, and operating temperature of the contacts. In operating conditions with minimal oxidation processes (low humidity, room temperature), the use of copper-based contacts is much more expedient because they are less costly compared to silver-based contacts.
10.1007-s11124-005-0065-5	-1		The ionization stages of copper and zinc at a galvanostatic anodic dissolution of Zn-Ag and Cu-Au alloys in acidic chloride environment are found to be electrochemically nonequilibrium. Selective dissolution of the alloys is limited by the transient mutual diffusion of components within a nonequilibrium surface layer. In terms of diverse theoretical models of the solid-phase mass transfer, the effects of the electrode surface microroughness, the apparent shift of the alloy-electrolyte interface boundary, and the relaxation of the vacancy subsystem are analyzed. The parameters of the diffusion layer, namely, its thickness, diffusivities, mutual diffusivities, and the over-equilibrium vacancy concentration were found. The latter characteristic is determined by the dissolution rate of the electrochemically negative alloy component, and, hence, the diffusivities and the Sand parameter of the diffusion kinetics substantially increase with an increase in the current density.
10.1007-s11164-015-2405-7	2	corrosion; surface; film; electrochemical; films; spectroscopy; layer; current; solution; potential; resistance; composition; x-ray; ions; showed	In industries where a heat exchanger is made up of Cu-Ni (90/10) alloy and seawater is used as a coolant, microbially influenced corrosion (MIC) is a serious problem. MIC of Cu-Ni (90/10) alloy in a seawater environment inoculated with sulfate-reducing bacteria was successfully inhibited by using two different inhibitor formulations viz. (1) 1,2,3-benzotriazole (BTAH) + tetrakis(hydroxymethyl)phosphonium sulfate (THPS) and (2) 5-(3-aminophenyl)tetrazole + THPS. Electrochemical impedance and potentiodynamic polarization studies showed an inhibition efficiency greater than 99 % for both formulations. The inhibitor formulation BTAH + THPS is so effective that in its presence, there is total absence of any MIC and microfouling even after 90 days, as evidenced by scanning electron micrographs and microbial count.
10.1007-s11182-011-9695-z	-1		A cycle of investigations carried out by the authors and devoted to the most important cellular dislocation substructure is generalized. Laws of formation of this substructure upon plastic strain of FCC Cu-Mn and Cu-Al alloy polycrystals are considered. The influence of the grain size, strain temperature, and alloy concentration on the parameters of evolving cellular dislocation substructures (DSS) is quantitatively analyzed by the transmission electron microscopy (TEM) method. Special attention is given to the kinetic phase transition in the defect subsystem leading to the formation of the cellular DSS. Based on modern dislocation models, it is demonstrated that hardening by the cellular DSS obeys the main dislocation laws.
10.1007-s11182-013-9954-2	-1		On the basis of experimental data obtained with the help of resistometric measurements, kinetic C-curves of the isothermal disorder -> order transformation have been constructed and the activation energy of the atomic ordering process in the quenched Cu-47 at% Pd alloy has been calculated. Deviations from the data in the literature are explained by differences in the methods of obtaining the initial disordered state of the alloy.
10.1007-s11182-013-9979-6	-1		A comparative study of spall fracture patterns for the heterophase Cu-8.45% Al-5.06% Ni alloy (D degrees t.%) in ultrafine- and coarse-grained states under shock-wave loading using the SINUS-7 electron accelerator is carried out. For electron energy of 1.4 MeV, pulse duration of 50 ns, and power density of 1.6 center dot 10(10) W/cm(2), the shock wave amplitude was 8 GPa and the strain rate was similar to 2 center dot 10(5) s(-1). It is established that the thickness of the spalled layer increased for both grained structures, and the degree of plastic strain decreased with increasing target thickness. Based on experimental data obtained and results of theoretical calculations, it is demonstrated that the spall strength of ultrafine- and coarse-grained structures is similar to 3 GPa. The data on the grained structure at different distances from the spall surface and spall fraction patterns and mechanism are presented.
10.1007-s11182-017-1109-4	-1		The approach which combines methods of crystal plasticity and deformable solid mechanics is used to explore the stress-strain state of a heavy-wall pipe made of dispersion-hardened Cu-based alloy and subjected to the uniform internal pressure. The distribution of the deformation and stress along the pipe wall is determined for various pipe geometry. The approximating equations are obtained to determine the yielding area and elastic and plastic strength limits.
10.1007-s11182-020-02097-1	-1		The paper deals with the dislocation and dislocation-disclination substructures of polycrystalline FCC alloys Cu-Al and Cu-Mn modified by tensile deformation. Observations are performed using the transmission electron microscopy. It is shown that the grain size of the alloy structure ranging from 10 to 240 mu m, can serve as a critical parameter in the low-stability state during the deformation and transition from one stage of hardening to another. The dependences are obtained for the parameters describing the defect substructure and the mean grain size. These dependences are compared with the structure and phase composition of the alloys. The critical grain size of about 100 mu m is found at a meso-level. When the grain size exceeds 100 mu m, the main role in defect accumulation play intracrystalline processes. At stage II, the strain-hardening coefficient does not depend on the grain size of >100 mu m and rapidly increases at a grain size of <100 mu m.
10.1007-s11182-021-02380-9	-1		The paper presents a thorough analysis of the dislocation structure of the Cu-12 at% Al alloy single crystals with [001] deformation axis at room temperature. It is shown that the multiple stages of strain hardening are associated with different types of the dislocation substructure appearing during the deformation process. The dislocation network is observed at all deformation stages and has specific properties at each stage. Measured are the parameters of the dislocation network and its evolution is studied. The dependences are obtained for the dislocation density, strain and shear stress. The linear dependence of tau(rho(1/2)) is true prior to strain at the beginning of stage III. It is found that the transition to stage III is caused by twinning, which drastically reduces the dislocation density.
10.1007-s11182-021-02447-7	-1		Transmission electron microscopy (TEM) is used to investigate the evolution of the dislocation substructure after active plastic deformation of copper-aluminum alloys with the aluminum content varying between 0.5-14 at%. Using TEM images, the types of the dislocation substructure are determined depending on the alloying element concentration and the strain intensity. The parameters of the defect structure, such as average scalar dislocation density, bending and torsion of the crystal lattice, and microtwin density are measured. It is found that the stacking fault energy exerts an effect on the defect accumulation.
10.1007-s11223-016-9739-2	-1		Cu-Zn alloy is an advanced material with deformation twinning mechanism, which is complicated by coupled effects of temperature and strain rate. In this paper, a theoretical model of Cu-Zn alloy is proposed, which accounts for the coupled effects of strain rate and temperature. The model can accurately predict the experimentally observed tendency of the spacing evolution of twin boundary (TB), and it confirms that low temperature and high strain rate promote deformation twinning. Moreover, it is shown that deformation twining is more susceptible to low temperature than to high strain rate, while TB spacing and twin layer thickness values decrease at high strain rates and low temperatures.
10.1007-s11249-005-8311-1	-1		Al2O3 particles reinforced Cu-Cr-Zr alloy matrix composite was fabricated through a powder metallurgy plus hot extrusion process by using the water atomization Cu-Cr-Zr powder as raw material. The effect of aging treatment on the tribological behavior of the composite was investigated. Experimental results show that tiny coherent precipitated phases were formed in the matrix after proper aging treatment and therefore good combination properties could be obtained. The wear rates of the Al2O3/CuCrZr composite and its matrix alloy were obviously influenced by the aging treatment, wherein the best wear resistance was reached at the aging temperature corresponding to the highest Vickers hardness. The major reason was that the depth of plastic deformation in the subsurface region was dramatically decreased due to the improvement of mechanical properties of the matrix, and therefore adhesion induced surface materials loss could be markedly alleviated. By comparing with the SiC20 vol%/Cu composite, it is indicated that the Al2O3/CuCrZr composite exhibited much better wear resistance as well as higher electrical conductivity.
10.1007-s11249-008-9341-2	17	wear; composites; coating; friction; composite; coatings; surface; tribological; properties; wear resistance; resistance; powder; sliding; matrix; wear rate	A novel Zn-coated graphite/Cu matrix self-lubricating composite contact strip (ZGCCS) was prepared by electroplating, pressing plus roasting and its tribological behaviors against the copper disk were studied under the simulated actual conditions, in comparison with the common graphite/Cu matrix self-lubricating composite (GCCS). The wear rate of both the ZGCCS and the GCCS increased with the increment of the current density and the sliding velocity. However, the ZGCCS exhibited wear resistance superior to the GCCS, indicating the electroplating Zn on graphite played an important role in improving the wear resistance and the wear rate of the former was only one-third of the latter at the sliding velocity of 41.7 m/s and with the current density of 285A/cm(2). Arc erosion wear, oxidative wear, and adhesive wear were the dominant mechanisms during the electrical sliding process. The arc erosion of the composite contact strip was remarkably reduced by the electroplating of Zn on graphite since the Zn-coated graphite particles were homogeneously distributed in the Cu matrix.
10.1007-s11249-009-9444-4	-1		The tribological properties of Cu-based and Zr-based bulk metallic glasses (BMGs) sliding against Si(3)N(4) under dry and water lubrication were studied on a pin-on-disc tribometer. The wear mechanisms of bulk metallic glasses were investigated based on the calculated flash temperature. The friction coefficients if fully amorphous alloy are about 0.7, while those of BMGs with nanocrytalline are a little higher. The wear rates of Cu-based BMG (V101) are about one order of magnitude lower than those of Zr-based BMG (Vit1) under dry friction, even two orders of magnitude lower under water lubrication. The wear resistance of bulk metallic glasses was influenced by the flash temperature. The calculated flash temperature (3,337 K) on the friction surface of Zr-based amorphous alloy exceeds its glass transition temperature, even its melting temperature. The high flash temperature leads to glass transition accompanied with viscous flow and material transfer, which is responsible for the poor wear resistance of Zr-based BMGs.
10.1007-s11249-010-9735-9	16	wear; composite; composites; powders; milling; particles; powder; wt; sliding; friction; hardness; matrix; mechanical; surface; properties	The response of Cu-40%Zn alloy to wear during unidirectional and bidirectional abrasion processes was investigated. It was observed that the mass loss of the alloy decreased as the number of times of changing the sliding direction was increased. Corresponding to this decrease in mass loss, hardness of the worn surface increased initially and then decreased. Cracking in the surface layer was analyzed to get an insight into the mechanism involved. Results of the study suggest that Baushinger's effect played a role when the sliding direction was alternated.
10.1007-s11249-011-9790-x	-1		Previously, we demonstrated a decrease in wear loss of Cu-40%Zn against a steel wheel during bidirectional sliding ascribed to Bauschinger's effect associated with diminished strain-hardening. However, the situation changed when the alloy was worn by a ceramic-grinding wheel. It was observed that the mass loss continuously increased with reversal of the sliding-direction although the corresponding hardness of worn surface also decreased. In this case, Bauschinger effect still functioned but the failure mode varied, leading to the different trend of response to wear against the ceramic-grinding wheel in comparison with that against the steel counter-face.
10.1007-s11249-018-1019-9	-1		In this work, the effect of the damping component with/without individual grooved surface features on the friction-induced vibration and noise (FIVN) and surface wear performance is studied experimentally and numerically. The experimental results show that introducing a grooved damping component in the system has a significantly improved capability in suppressing the generation of FIVN. In addition, it is observed that the friction system with a grooved damping component suffers slighter wear. Numerical results show good agreement with the FIVN events observed in the experimental test. Through analysing the deformation behaviour of damping component and the contact behaviour of the friction system during friction process, it is speculated that the deformation behaviour of damping component plays a significant role in affecting the contact pressure and FIVN behaviour. In addition, linking the vibration performance and wear evolution, the connection between damping, and vibration and wear behaviour is discovered, which can further explain why the friction system with a grooved damping component shows improved capability in suppressing the FIVN of friction system.
10.1007-s11249-018-1025-y	-1		Friction and wear are accompanied by severe plastic deformation of surface layers similar to that observed under different processes of grain refinement. Recently, a dependence of tribological properties for four fcc metals (Ag, Cu, Ni, and Al) under friction in boundary lubrication was reported. A connection between friction and wear properties and stacking fault energy (SFE) of the studied metals was considered. Steady-state friction is mainly determined by deformation microstructure and chemical interaction in thin surface layers. The objectives of this work are to study the evolution of the microstructure with the depth of plastic deformation after friction of Al and Cu, to evaluate the effect of SFE on microstructure and wear loss, and to analyze the chemical composition of thin surface layers of Cu and Al and their correlation with the microstructure and wear properties of the studied metals. Friction surfaces were examined with a field emission scanning electron microscope. The cross-sectional TEM lamellae were prepared using focused ion beam. Evolution of deformation microstructure and chemistry of surface layers of Cu and Al after friction in the lubricant conditions were estimated by STEM, TEM, and XPS analyses.
10.1007-s11249-018-1075-1	16	wear; composite; composites; powders; milling; particles; powder; wt; sliding; friction; hardness; matrix; mechanical; surface; properties	Pin-on-disc testing was used to investigate the friction and wear behaviour of a Cu-based metal matrix composite dry sliding against three different martensitic steels. The tests were carried out at two contact pressures (0.5 and 1 MPa) and two sliding velocities (1.57 and 7 m/s), and the results were explained by considering the characteristics of the friction layers formed on the pin and disc surfaces during sliding. At 7 m/s, pin and disc wear was very mild in every condition, because the high flash temperatures achieved during sliding induced intense oxidation of the disc asperities, irrespective of the steel disc compositions. At 1.57 m/s, the steel composition played an important role. When using a heat-treated steel and a conventional martensitic stainless steel, pin and disc wear was by 'low-sliding speed tribo-oxidation', regarded as mild wear. However, when using a martensitic stainless steel with a very high Cr-content and a very low C-content, i.e. by a very high oxidation resistance, pin and disc wear was by adhesion/delamination at 0.5 MPa, and thus severe in nature. The results presented herewith clearly suggest the importance of selecting suitable steel counterfaces in the optimization of the tribological systems tribological involving Cu-based metal matrix composites as a mating material.
10.1007-s11249-019-1262-8	-1		Tribological behaviors of an ultrahigh strength Cu-15Ni-8Sn-0.2Y alloy sliding against TC6 titanium alloy in deionized water and seawater under various normal loads and sliding speeds were evaluated. The friction coefficient and wear rate of the studied alloy in deionized water were higher than those in seawater. Seawater played cooling, lubricating, and corrosive roles during the friction process. A friction model for calculating ploughing component was established, which could explain the influence mechanism of the normal load on the friction coefficient and wear rate. Chloride ions easily penetrated the passive film and damaged it due to the wear, causing increased corrosion and corrosive products. The corrosive products such as Mg(OH)(2) and CaCO3 played important roles in reducing friction and wear. [GRAPHICS] .
10.1007-s11249-021-01550-7	16	wear; composite; composites; powders; milling; particles; powder; wt; sliding; friction; hardness; matrix; mechanical; surface; properties	We studied the microstructure of the transfer layer and its effect on the wear mechanism and wear properties of an aged Cu-15Ni-8Sn alloy against 100Cr6 bearing steel during dry sliding by changing the applied load. The results indicate that the aged Cu-15Ni-8Sn alloy shows different wear behaviour and wear properties when the applied load changes; specifically, the average friction coefficient and specific wear rate decrease quickly with increasing applied load under steady wear conditions. The sample tested under a relatively high applied load showed the best wear performance because the oxide layer in the transfer layer. The main wear mechanisms were found to change with variation in the applied load. Metallic nanocrystalline particles and relatively ductile copper oxides promoted the formation of a thick and dense oxide layer. Changes in the thickness and morphology of the oxide layer under different loads can significantly affect the wear mechanisms.
10.1007-s11249-022-01634-y	17	wear; composites; coating; friction; composite; coatings; surface; tribological; properties; wear resistance; resistance; powder; sliding; matrix; wear rate	In this work, the lubricating models of Cu-Zn alloy with and without the Zinc oxide (ZnO) layer were established. Molecular dynamics (MD) simulation is employed to investigate the lubrication behavior of n-hexadecane on the ZnO layer at the nanoscale. The diffusion of lubricants molecules, and the interaction and stick-slip effect between the friction pairs and the lubricants are systematically explored. The results show that the ZnO layer limits the diffusion of n-hexadecane molecules and the formed lubricating films in the model of the substrate with the ZnO layer are obvious and stable. During the sliding process, ZnO molecules have strong interaction with lubricants molecules and adsorb lubricants molecules on the surface to form adsorption film. The stick-slip effect in the lubricating films generates periodic shear stress and reduces the wear of the friction pair. The ZnO layer causes lubricants molecules to be arranged regularly on the surface into a stable structure.
10.1007-s11356-023-31244-7	2	corrosion; surface; film; electrochemical; films; spectroscopy; layer; current; solution; potential; resistance; composition; x-ray; ions; showed	The corrosion of marine engineering equipment not only threatens human security and ecological environment but also increases energy consumption, restricting the sustainable development of marine economies and industries. The tidal region is a complex and challenging environment that can cause severe corrosion of facilities and affect microbial activities. However, the current understanding of the mechanisms underlying microbiologically influenced corrosion (MIC) of tidal region is insufficient. To address this issue, the effect of Pseudomonas aeruginosa on a Cu-Zn-Ni alloy in the simulative tidal region was investigated by chemical and molecular biological analysis in this study. The results demonstrated that P. aeruginosa formed thicker biofilms on the Cu-Zn-Ni alloy samples under the full exposure, accelerating corrosion compared to sterile controls. Interestingly, the corrosion of P. aeruginosa toward the Cu-Zn-Ni alloy was inhibited in the simulative tidal region. This inhibition behavior was relevant to the reduction in the quantity of sessile cells and cell activities. The expression down-regulation of genes encoding phenazines induced the decrease in electron transfer mediators and weakened the MIC of P. aeruginosa on alloy samples in the simulative tidal region. The research sheds light on the characteristics of P. aeruginosa and corrosion products on the Cu-Zn-Ni alloy, as well as their interaction mechanisms underlying corrosion in the simulative tidal region. The study will facilitate the evaluation and control of MIC in the tidal region, contributing to the development of sustainable strategies for preserving the integrity and safety of marine facilities.
10.1007-s11431-011-4729-x	-1		Single-phase and dual-phase metallic glasses as well as metallic glass based composites were synthesized in the Cu-Mo-Hf ternary metal system by 200 keV xenon ion beam mixing of far-from-equilibrium. It was found that Mo-Hf-based and Cu-Mo-based single-phase metallic glasses could be obtained at compositions around Cu17Mo20Hf63 and Cu34Mo57Hf9, respectively. Interestingly, at the nearly equal-atomic stoichiometry of Cu38Mo31Hf31, a dual-phase Cu-Mo-Hf metallic glass, consisting both of the Mo-Hf-based and Cu-Mo-based phases, was first obtained at relatively low irradiation doses ranging from (1-5)x10(15) Xe+/cm(2), and a single-phase metallic glass was eventually obtained at a dose of 7x10(15) Xe+/cm(2). In addition, two glass-based composites were obtained at the compositions of Cu14Mo62Hf24 and Cu77Mo14Hf9, and they consisted of the Mo-Hf based and Cu-Mo based metallic glasses, dissolved with some uniformly distributed BCC Mo-based and FCC Cu-based crystalline solid solutions, respectively. The formation mechanism of the above described non-equilibrium alloy phases was also discussed in terms of the atomic collision theory.
10.1007-s11431-012-5037-9	-1		This paper is devoted to developing a yield criterion that can model the asymmetry and anisotropy in yielding of pressure insensitive metals, in terms of accuracy and simplicity of formulation. First, a new isotropic yield criterion, which can model the asymmetry in yielding of pressure insensitive metals, is proposed. Further, using Cazacu's generalizations to anisotropic conditions of the invariants of the deviatoric stress, the proposed isotropic yield criterion is extended to orthotropy. The proposed anisotropic criterion has a quite simple form, and the number of material constants involved is only half of that of Cazacu's (2004) yield criterion. Compared to Hill's (1948) yield criterion, the proposed anisotropic yield criterion has three additional constants, which are used to model the tension-compression asymmetry of materials. All the material constants involved in the criterion can be determined by simple tests. The proposed criterion reduces to Hill's (1948) yield criterion if the tensile and compressive yield stresses are equal. In other words, the proposed anisotropic yield criterion can be considered as an extension of Hill's (1948) criterion to tension-compression asymmetry materials. The anisotropic yield criterion is used to describe the plastic response of Cu-Al-Be shape memory alloy (data after Laydi and Lexcellent) and Ni3Al based intermetallic alloy IC10 sheets. It is shown that the proposed yield criterion can describe very well the asymmetry and anisotropy observed in those materials.
10.1007-s11431-012-5107-z	11	glass; bulk; metallic; bulk metallic; gfa; bmg; glassy; metallic glass; ability; bulk metallic glass; amorphous; addition; crystallization; mm; glass-forming	Little is known about the mechanical properties of bulk metallic glassy alloys (BMGs) after cryogenic treatment. In this study, the effects of cryogenic treatment (CT) on the microstructural transition and the mechanical properties of Cu-based bulk metallic glass (BMG) were studied. The results showed that submicron AlCu2Zr and Cu5Zr phases can precipitate from the Cu-Zr-Ag-Al matrix after 192 h CT. The formation of these nanometer-sized crystalline phases substantially enhanced the mechanical properties of the bulk amorphous alloy. The micro-hardness and the compressive strength were found to increase respectively from 501 HV and 1510 MPa to 595 HV and 1910 MPa after cryogenic treatment. CT is a promising approach to strengthening metal glasses.
10.1007-s11431-013-5362-7	17	wear; composites; coating; friction; composite; coatings; surface; tribological; properties; wear resistance; resistance; powder; sliding; matrix; wear rate	In this paper Cu-WS2-graphite-WS2 nanotube composites were fabricated by powder metallurgy hot pressing method. The effect of current polarity on the wear rates and contact voltage drops of the composites were investigated using a brush-on-slip ring tribometer rubbing against Cu-5 wt% Ag alloy ring in air and vacuum, respectively. The worn surfaces of the composites were analyzed by scanning electron microscopy (SEM) and X-ray photoelectron spectroscopy (XPS). Surface profile curves of the worn tracks were measured using the surface profiler. The results demonstrated that the current polarity has a significant effect on the wear rates and contact voltage drops of the composites in both air and vacuum conditions. Positive brush possesses a higher wear rate compared with the negative brush in the air atmosphere since the electrical field direction activates oxidation at the positive brush surface while inhibits oxidation at the negative brush surface. Except for the regular wear losses, the combined effect of molten metal bridge erosion and arc erosion cause the positive brush to lose extra material and the negative brush to gain extra material, so the positive brush shows a higher wear rate in the vacuum condition. The contact voltage drop of the positive brush is lower than that of the negative brush in the air atmosphere, but contrarily, the positive brush shows a higher contact voltage drop in the vacuum condition.
10.1007-s11431-015-5774-7	-1		A Cu-50Cr alloy was treated by the high current pulsed electron beam (HCPEB) at 20 and 30 keV with pulse numbers ranging from 1 to 100. Surface morphologies and microstructures of specimens before and after the treatments were investigated by employing scanning electron microscopy and X-ray diffraction. Results show that the HCPEB technique is able to induce remarkable surface modifications for the Cu-50Cr alloy. Cracks in Cr phases appear even after one-pulse treatment and their density always increases with the pulse number. Formation reason for these cracks is attributed to quasi-static thermal stresses accumulated along the specimen surface. Craters with typical morphologies are formed due to the dynamic thermal field induced by the HCPEB and they are found to prefer the sites near cracks or boundaries between neighboring Cr phases. Another microstructural characteristic produced by the HCPEB is the fine Cr spheroids, which are determined to be due to occurrence of liquid phase separation in the Cu-50Cr alloy. Finally, a general microstructural evolution profile that incorporates various HCPEB-induced surface features is tentatively outlined.
10.1007-s11431-020-1617-x	1	shape; memory; shape memory; damping; martensite; martensitic; damping capacity; transformation; capacity; strain; superelasticity; temperature; cu-al-mn; shape memory effect; effect	In this study, two Cu-Al-Mn-Fe polycrystalline alloys were prepared, and their microstructure, reversible martensitic transformation, mechanical properties and shape memory effects were investigated. The results show that the reversible martensitic transformation temperatures of the studied alloys are between room temperature and 373 K, which are suitable for practical applications. Two typed martensites of 18R and 2H coexist both in two alloys. The bcc beta (FeAl) nanoparticles are Fe-rich, Mn-rich and Cu-poor, whereas the martensite is Cu-rich, Fe-poor and Mn-poor. The size of nanoparticles ranges from tens to hundreds of nanometers. Full shape recovery property is displayed in Cu-12.9Al-4.5Mn-2.6Fe alloy all the time while applying different deformation from 5% to 8%. The maximum recoverable strain is up to 4.4% with a recovery rate of 100%.
10.1007-s11433-010-4136-5	-1		The atomic and electronic structures of amorphous Cu (x) Zr100-x (x=36, 46, 50, 56, 64) alloys were simulated using first-principle calculations within a 400-atom supercell. The pair correlation function, coordination numbers, local cluster structures and electronic density of states were analyzed. Reasonable agreements between the theory and the experiments were obtained. The amorphous alloys exhibit different local cluster structures and can all be explained with cluster formulas [cluster](glue)(1,3), where the clusters are derived from known Cu-Zr compounds. There is always a pseudogap in the density of state at the Fermi level.
10.1007-s11433-011-4256-6	0	solidification; phase; magnetic; magnetic field; undercooling; field; liquid; separation; peritectic; immiscible; cu-; dendrite; phase separation; microstructure; primary	Rapid solidification of binary wCu-22% Sn peritectic alloys and Cu-5% Sn-5% Ni-5% Ag quaternary alloys was accomplished by glass fluxing, drop tube and melt spinning methods. The undercooled, by glass fluxing method, Cu-22% Sn peritectic alloy was composed of alpha(Cu) and delta(Cu41Sn11) phases. If rapidly solidified in a drop tube, the alloy phase constitution changed from alpha(Cu) and delta(Cu41Sn11) phases into a single supersaturated (Cu) phase with the reducing of droplet diameter, and the maximum solubility of Sn in (Cu) phase extended to 22%. The Cu-5% Sn-5% Ni-5% Ag quaternary alloy was composed of (Cu) and (Ag) phases under the containerless processing condition in a drop tube, and the solute microsegregation of (Cu) phase was obvious. When the Cu-5% Sn-5% Ni-5% Ag quaternary alloy was solidified by melt spinning method, microsegregation was suppressed and solute trapping occurred. The experimental results show that the microstructures of primary (Cu) phase in the two alloys transfer from coarse dendrites into equiaxed grains with the increase of cooling rate and undercooling, which is accompanied by the grain refinement effect.
10.1007-s11433-011-4376-z	-1		Introducing heterogeneities into the structure is an effective way to enhance the plasticity in metallic glasses (MGs). As natural heterogeneity, the original randomly distributed free volume in MGs has been found to be in favor of plasticity. However, the exact correlation between the free volume distribution and mechanical response is still unclear. In this paper, we investigate the shear banding in MGs with different structural disorders, characterized by both the free volume concentration (FVC) and the free volume dispersion (FVD). It is found that, either high FVC or wide FVD leads to low activation stress of shear band; wide FVD promotes the multiplication of shear bands but high FVC restricts it. It reveals that the yield strength in MGs is dependent on the amount of free volume while the plasticity mainly relies on the distribution. An optimum combination of the two aspects probably helps to design a MG of both good plasticity and high strength .
10.1007-s11434-007-0371-1	0	solidification; phase; magnetic; magnetic field; undercooling; field; liquid; separation; peritectic; immiscible; cu-; dendrite; phase separation; microstructure; primary	Rapid growth behavior of zeta phase has been investigated in the undercooling experiments of Cu-14%Ge, Cu-15%Ge, Cu-18.5%Ge and Cu-22%Ge alloys. Alloys of the four compositions obtain the maximum undercoolings of 202 K(0.17T (L)), 245 K(0.20T (L)), 223 K(0.20T (L)) and 176 K(0.17T (L)), respectively. As the content of Ge increases, the microstructural transition of alpha(Cu) dendrite + zeta peritectic phase -> zeta peritectic phase -> zeta dendrite + (epsilon+zeta) eutectic takes place in the alloy at small undercooling, while the microstructural transition of fragmented alpha(Cu) dendrite + zeta peritectic phase -> zeta peritectic phase -> zeta dendrite + epsilon phase happens in the alloy at large undercooling. EDS analysis of the Ge content in zeta peritectic phase indicates that undercooling enlarges the solid solubility of alpha dendrite, which leads to a decrease in the Ge content in zeta phase as undercooling increases. In the Cu-18.5%Ge alloy composed of zeta peritectic phase, the Ge content in zeta phase increases when undercooling increases, which is due to the restraint of the Ge enrichment on the grain boundaries by high undercooling effect.
10.1007-s11508-008-2013-5	4	transformation; martensite; martensitic; phase; shape; beta; memory; shape memory; temperature; temperatures; martensitic transformation; gamma; transformation temperatures; effect; thermal	Peculiarities of the kinetics of the A1-B2 phase transformations in the Cu-47 at. % Pd (here-inafter, Cu-47Pd) alloy that occur with changing degree of preliminary plastic deformation, heating rate, annealing temperature, and the shape and dimensions of samples are studied. Upon ordering of the preliminarily deformed alloy, the structure of the near-surface layer was found to differ essentially from that of the alloy volume. The rate of phase transformations in the near-surface layer was shown to be substantially lower than that of analogous processes occurring in the alloy volume. Possible causes of the phenomena observed are considered; the data obtained are compared with those available in the literature.
10.1007-s11581-016-1888-6	2	corrosion; surface; film; electrochemical; films; spectroscopy; layer; current; solution; potential; resistance; composition; x-ray; ions; showed	CuGaS2 thin film is fabricated with electrochemical deposition of Cu-Ga alloys from alcohol solution to eliminate the interference of hydrogen evolution reaction (HER). The process involves electrodeposition of Cu-Ga precursor on molybdenum substrate and subsequential annealing in sulfur vapor. The formation of CuGa2 alloy in precursor is observed and pure ternary chalcopyrite CuGaS2 phase in good polycrystalline structure without secondary phase is obtained after thermal treatment. The influence of the applied deposition potential on the crystalline phase, morphology, compositions, and carrier concentration of the films were investigated. The results show that an optimum choice of electrodeposition potential is necessary to obtain a pure crystallized CuGaS2 thin film. A lower absolute deposition potential results in a higher Cu/Ga ratio and the emergence of CuS secondary phase after annealing in sulfur atmosphere. The crystal size of the formed CuGaS2 phase with thermal annealing process increases with the positive shift of deposition potential. Impedance spectroscopy test demonstrates the semiconductor property of the synthesized CuGaS2 polycrystalline thin films are all p-type. The carrier density of the obtained CuGaS2 thin films increases with the negative shift of deposited potential.
10.1007-s11581-019-03418-2	2	corrosion; surface; film; electrochemical; films; spectroscopy; layer; current; solution; potential; resistance; composition; x-ray; ions; showed	Copper and copper-zinc alloys were electrochemical prepared from Cu2O-ZnO mixed oxides in urea and 1-butyl-3-methylimidazolium chloride deep eutectic solvent at 383 K. The electrochemical reduction and nucleation mechanism of copper and copper-zinc alloys were investigated by cyclic voltammetry and chronoamperometry. Cyclic voltammetry showed that copper species [Cu2ClO center dot urea](-) was reduced to copper at-0.68 V (vs. Ag), while zinc species [ZnClO center dot urea](-) was reduced to zinc and formed copper-zinc alloy at-1.8 V (vs. Ag). Chronoamperometry indicated that copper particles were electrodeposited by progressive nucleation with diffusion-controlled growth process in urea-BMIC-Cu2O solutions, and the average diffusion coefficient of copper complex ions was determined to be 2.79 x 10(-8) cm(2) s(-1). On contrast, the electrodeposition of copper-zinc alloy proceeded via combination of 3D instantaneous and progressive nucleation. On the other hand, copper and copper-zinc alloys were electroplated on to a stainless steel substrate and characterized by X-ray diffraction, scanning electron microscopy, and energy dispersive spectroscopy.
10.1007-s11595-005-1022-5	-1		The kinetics of internal oxidation of Cu-Al alloy spheres, containing up to 2.214% mole fraction Al was investigated in the temperature range 1 023 K to 1 273 K, and the depth of internal oxidation was measured in the microscopy. A kinetic equation was derived to describe the internal oxidation of Cu-Al alloy spheres, which was checked experimentally by means of oxidation depth measurements. The results show that the derived equation is exact enough to describe the kinetics of internal oxidation of Cu-Al alloy spheres. Based on this equation and the oxidation depth measurements, the permeability of oxygen in solid copper has been obtained. Investigation also shows that in the process of internal oxidation, there is no evidence for preferential diffusion along grain boundaries.
10.1007-s11595-005-1088-0	-1		The effects of annealing temperatre on the electrical conducitivity and mechanical property of Cu-Te alloys were studied via an AG-10TA electronic universal machine, an SB2230 digital electric bridge, SEM, EDS and XPS. The results show the electrical conductivity increases while the tensile strength fluctuates when the annealing temperature becomes higher because the recrystallization occurs during the annealing process, leading to the density of dislocation decreasing, grain size growing up, but the second phase precipitating sufficiently and simultaneously.
10.1007-s11595-007-5717-7	4	transformation; martensite; martensitic; phase; shape; beta; memory; shape memory; temperature; temperatures; martensitic transformation; gamma; transformation temperatures; effect; thermal	The influence of processing parameters on the microstructure and shape memory effect of Cu-26.1Zn-4.8Al alloy was investigated. The treated specimens were characterized by metallography, X-ray diffraction (XRD) and transmission electron microscopy (TEM) to explain the mechanism of shape memory effect in Cu-26.1Zn-4.8Al alloy. The results reveal that the shape memory effect is markedly increased by appropriate quenching and ageing process. XRD shows that gamma phase precipitates from martensite when aged at higher temperature and gamma precipitates impair the shape memory effect. TEM analysis indicate that the substructure of plate-like martensite consists of twins
10.1007-s11595-010-1068-x	-1		The most common and serious defect in Cu-Ni alloy casting is porosity. To solve the problem, accurate casting design and proper design of gating system are necessary. It can be predicted and designed by means of computer simulation of casting solidification. Based on the casting process of the Cu-Ni alloy, the simulation software of diathermanous-flowing-stress coupling ProCAST was used to simulate the Cu-Ni alloy solidification process about the defects and temperature field. By combining experimental results with the simulation results, the quality of casting on some cooling conditions were analyzed. Furthermore, a better cooling condition for solidification process of the Cu-Ni alloy was chosen to improve the quality of the casting. The simulation results indicate that the quality of Cu-Ni alloy casting is the best when it is on the cooling condition of the permanent mold with the insulated riser system.
10.1007-s11595-011-0334-x	-1		The oxide dispersion strengthened copper alloys are attractive due to their excellent combination of thermal and electrical conductivities, high-temperature strength and microstructure stability. To date, the state-of-art to fabrication of them was the internal oxidation (IO) process. In this paper, alumina dispersion strengthened copper (ADSC) powders of nominal composition of Cu-2.5 vol%Al2O3 were produced by reaction milling (RM) process which was an in-situ gas-solid reaction process. The bulk ADSC alloys for electrical and mechanical properties investigation were obtained by sintering and thereafter hot,extrusion. After the hot consolidation processes, the fully densified powder compacts can be obtained. The single gamma-Al2O3 phase and profile broaden effects are evident in accordance with the results of X-ray diffraction (XRD); the HRB hardness of the ADSC can be as high as 95; the outcomes should be attributed to the pinning effect of nano gamma-Al2O3 on dislocations and grain boundaries in the copper matrix. The electrical conductivity of the ADSC alloy is 55%IACS (International Annealing Copper Standard). The room temperature hardness of the hot consolidated material was approximately maintained after annealing for 1 h at 900 degrees C in hydrogen atmosphere. In terms of the above merits, the RM process to fabricating ADSC alloys is a promising method to improve heat resistance, hardness, electrical conductivity and wear resistance properties etc.
10.1007-s11595-013-0662-0	15	aging; strength; conductivity; electrical conductivity; electrical; mpa; treatment; strengthening; degrees; cu-; cold; precipitation; tensile strength; tensile; iacs	The microstructures after casting and extruding, the mechanical properties and electrical conductivity after RRA treatment of conventional DC casting and low frequency electromagnetic casting (LFEC) 7075 aluminum alloy were investigated. The results showed that finer grains which distributed more homogeneously was obtained in LFEC ingots compared with those conventional DC ingots. The extruded bars of LFEC alloy kept its fine grain features of original as-cast structure. In the RRA treatment, with the extension of second aging time, the tensile strength and hardness of alloy decreased, but the electrical conductivity increased. Meanwhile, as the second aging temperature raised, the phase change rate in precipitation also increased. Under the same conditions, extruded bars of LFEC alloy had better performance than that of conventional DC cast alloy. The optimum RRA heat treatment process was 120 A degrees C/24 h+180 A degrees C/30 min+120 A degrees C/24 h . The LFEC extruded bars acquired tensile strength 676.64 MPa, hardness 198.18, and electrical conductivity 35.7% IACS respectively, which were higher than that in the T6 temper, indicating that a notable RRA response takes place in LFEC extruded bars, whose second-step retrogression time was 30 min, and it was suitable for mass production.
10.1007-s11595-013-0663-z	16	wear; composite; composites; powders; milling; particles; powder; wt; sliding; friction; hardness; matrix; mechanical; surface; properties	Nanocrystalline Cu-5 wt%Cr alloy powders were fabricated by mechanical alloying (MA). The effects of MA processing parameters on the crystallite size, solid solubility, and microstructures of the Cu-5 wt%Cr alloys were investigated including type and size distribution of the grinding medium and ball-topowder weight ratio (BPR). The results show that the crystallites were refined effectively and solid solubility of Cr in Cu was extended when heavier ball and higher BPR were adopted. The maximum solubility is extended up to 5.6 at% (namely 4.6 wt%) Cr in Cu by use of a combination of large and small size WC-Co balls with BPR of 30:1. A Cu-5 wt%Cr supersaturated solid solution alloy bulk is obtained by spark plasma sintering the as-milled powders at 900 A degrees C for 5 min.
10.1007-s11595-018-1804-1	15	aging; strength; conductivity; electrical conductivity; electrical; mpa; treatment; strengthening; degrees; cu-; cold; precipitation; tensile strength; tensile; iacs	The Cu-15Cr in-situ fiber-reinforced composites sheets were prepared by cold drawing combined with cold rolling process. The evolution process of Cr fibers was studied, and when cold rolling reduction epsilon = 95%, the morphology of Cr fiber at different annealing temperature and the thermal stability of Cu-15Cr alloy were studied. Microstructure was also studied by scanning electron microscopy (SEM). Meanwhile, the tensile strength of the alloy was tested by means of a precision universal tester, and the resistance value of the alloy was determined by using a digital micro-Euclidean instrument. The experimental results show that, with the increase of deformation, Cr dendrites evolve into homogeneous and parallelly arranged Cr fibers, and the cross-section of Cr fibers undergoes a V shape transition to-shape. In addition, spheroidization of the Cr fibers occurs on edges and extends to the center as annealing temperature rises. Moreover, the Cr fibers remains stable when the annealing temperature is below 550 degrees C. Furthermore, the tensile strength of Cu-15Cr alloy decreases gradually as the annealing temperature increases, while the electrical conductivity maximizes when annealing at 550 degrees C. Our study also shows that Cu-15Cr alloy has obtained a better comprehensive performance with tensile strength of 656 MPa and electrical conductivity of 82% IACS after annealing at 450 degrees C.
10.1007-s11595-018-1916-7	11	glass; bulk; metallic; bulk metallic; gfa; bmg; glassy; metallic glass; ability; bulk metallic glass; amorphous; addition; crystallization; mm; glass-forming	Zr-Al-(Y, Ag) amorphous alloy ribbons of Cu50Zr42Al8, Cu46Zr47-xAl7Yx(x=2, 5), Cu43Zr42Al8Ag7, and Cu43Zr42Al8Ag5Y2 were prepared using the single roller melt-spinning method. The glass forming ability and non-isothermal crystallization behavior of the amorphous alloys were investigated by means of X-ray diffraction (XRD) and differential scanning calorimetry (DSC) in a continuous heating mode. The experimental results show that the glass forming ability and thermal stability of Cu-Zr-Al amorphous alloys are improved by adding minor amounts of Y and Ag, and the effect of Ag on the glass forming ability is more significant than that of Y. Compared to the Cu50Zr42Al8 alloy, the width of the supercooled liquid region of the Cu46Zr47-xAl7Yx(x = 2 and 5) alloys increased by 19 K and 30 K, respectively. The reduced glass transition temperature (T-rg) and the parameter. of the two alloys enhanced separately. Compared to the Cu50Zr42Al8 alloy, the T-rg and gamma values of both Cu43Zr42Al8Ag7 and Cu43Zr42Al8Ag5Y2 alloys enhanced noticeably up to 0.619, 0.417, and 0.609, 0.412, respectively. The crystallization activation energies of the amorphous alloys calculated by the Kissinger and Flynn Wall Ozawa equations increased with the addition of minor Y and Ag into the Cu50Zr42Al8 alloy. The addition of Y and Ag significantly improved the thermal stability of the Cu50Zr42Al8 amorphous alloy.
10.1007-s11595-021-2395-9	0	solidification; phase; magnetic; magnetic field; undercooling; field; liquid; separation; peritectic; immiscible; cu-; dendrite; phase separation; microstructure; primary	2wt% TiB2/Cu composite powders were fabricated in situ by reactive gas atomization. The fabricated composite powder exhibits high sphericity, and the powder sizes range from 5 mu m to 150 mu m. The morphology of the Cu matrix and the distribution of the TiB2 particles in the composite powders vary with the powder size. The critical transitions of interface morphologies from dendritic-to-cellular and cellular-to-planar interfaces occurs when the composite powder sizes decrease to 34 mu m and 14 mu m, respectively. Compared with pure Cu droplets, the composite droplets undergo critical transition of the interface morphologies at a smaller droplet size corresponding to a higher cooling rate because the existence of TiB2 particles can cause instability in the advancing solidification front and heterogeneous nucleation. With decreasing powder size, the extent of the TiB2 particle interdendritic segregation decreases as the result of enhanced engulfment of TiB2 particles by the advancing solidification front.
10.1007-s11595-023-2715-3	-1		The molten Cu60Ni35Co5 ternary alloy was undercooled by fluxing method and solidified by natural cooling method. The microstructure of all undercooled samples were analyzed. It is found that the rapidly solidified Cu60Ni35Co5 alloy has undergone two grain refinement phenomena within the undercooling range, and its microstructure and morphology change with the undercooling through the transformation process of coarse dendrite-equiaxed dendrite-oriented fine dendrite-equiaxed crystal. The refined structure with the maximum undercooling Delta T of 253 K was selected for electron backscatter diffraction (EBSD) and transmission electron microscopy (TEM) tests. EBSD results show that the refined structure contains a high proportion of large angle grain boundaries (LAGBs), a large number of randomly oriented grains, and high proportion of twins, while TEM results show that the dislocation density in most areas is relatively low. The above characteristics confirm that the solidification structure is refined due to recrystallization behavior under high undercooling.
10.1007-s11595-023-2804-3	-1		Dense zirconium coatings on copper substrates were obtained in an alumina crucible and a stainless steel crucible from FLiNaK-K2ZrF6 molten salt at 1 023 K. Due to the potential differences between copper and zirconium, zirconium can diffuse into the copper substrate to form zirconium alloys on the surface of copper substrates in the course of deposition. The coating deposited in a stainless steel crucible has a gray surface. The components of the coating are mainly CuZr2 alloy and Cu10Zr7 alloy, and, the outermost layer of the coating is a layer of amorphous pure zirconium. The coating deposited in an alumina crucible has a silvery white metallic luster. The components of the coating are mainly Cu-Zr-Al intermetallic compounds, AlCu2Zr, ZrAl, AlCu and CuZr. Furthermore, two types of zirconium coatings can greatly increase the hardness of the substrate.
10.1007-s11595-023-2844-8	-1		Both Cu60Ni38Co2 and Cu60Ni40 alloy were naturally cooled after rapid solidification from the liquid phase. The transformation law of the microstructure characteristics of the rapidly solidified alloy with the change of undercooling (Delta T) was systematically studied. It is found that the two alloys experience the same transformation process. The refinement structures under different undercoolings were characterized by electron backscatter diffraction (EBSD). The results show that the characteristics of the refinement structure of the two alloys with low undercooling are the same, but the characteristics of the refinement structure with high undercooling are opposite. The transmission electron microscopy (TEM) results of Cu60Ni38Co2 alloy show that the dislocation network density of low undercooled microstructure is lower than that of high undercooled microstructure. By combining EBSD and TEM, it could be confirmed that the dendrite remelting fracture is the reason for the refinement of the low undercooled structure, while the high undercooled structure is refined due to recrystallization. On this basis, in the processing of copper base alloys, there will be serious work hardening phenomenon and machining hard problem of consciousness problems caused by excessive cutting force. A two-dimensional orthogonal turning finite element model was established using ABAQUS software to analyze the changes in cutting speed and tool trajectory in copper based alloy ultrasonic elliptical vibration turning. The results show that in copper based alloy ultrasonic elliptical vibration turning, cutting process parameters have a significant impact on cutting force. Choosing reasonable process parameters can effectively reduce cutting force and improve machining quality.
10.1007-s11595-024-2933-3	-1		In the present study, the Cu-(1 wt%-6 wt%) Ag alloys were prepared by melting, forging and wire drawing. The effects of plastic deformation on microstructure evolution and properties of the alloys were investigated. The results show that non-equilibrium eutectic colonies exist in the Cu- (3 wt%-6 wt%) Ag alloy and no eutectic colonies in the 1 wt%-2 wt% Ag containing alloys. These eutectic colonies are aligned along the drawing direction and refined with the increase of draw ratio. Attributed to the refinement of eutectic colonies, the Cu-Ag alloy exhibits higher strength with the increase of draw ratio. The Cu-6Ag alloy exhibits excellent comprehensive properties with a strength of 930 MPa and a conductivity of 82 %IACS when the draw ratio reaches 5.7.
10.1007-s11595-025-3095-7	-1		The evolution of the microstructure and morphology of Cu55Ni45 and Cu60Ni40 alloys under varying degrees of undercooling was investigated through molten glass purification and cyclic superheating technology. By increasing the Cu content, the effect of Cu on the evolution of the microstructure and morphology of the Cu-Ni alloy during undercooling was studied. The mechanism of grain refinement at different degrees of undercooling and the effect of Cu content on its solidification behaviour were investigated. The solidification behaviour of Cu55Ni45 and Cu60Ni40 alloys was investigated using infrared thermometry and high-speed photography. The results indicate that both Cu55Ni45 and Cu60Ni40 alloy melts undergo only one recalescence during rapid solidification. The degree of recalescence increases approximately linearly with increasing undercooling. The solidification front of the alloy melts undergoes a transition process from a small-angle plane to a sharp front and then to a smooth arc. However, the growth of the subcooled melt is constrained to a narrow range, facilitating the formation of a coarse dendritic crystal morphology in the Cu-Ni alloy. At large undercooling, the stress breakdown of the directionally growing dendrites is primarily caused by thermal diffusion. The strain remaining in the dendritic fragments provides the driving force for recrystallisation of the tissue to occur, which in turn refines the tissue.
10.1007-s11595-025-3151-3	-1		Using a combination of selective laser melting (SLM) and de-alloying methods, we prepared ultrafine crystalline nanoporous Cu. The resulting porous Cu exhibits grains ranging from 30-90 nm in size, pore sizes ranging from 50-300 nm, and a ligamentous structure with melt pool morphology. It is believed that the formation of ultrafine grains with nanoporous microstructures occurs due to the fast cooling rate of the melt pool, repeated heating during the printing process, and the intrinsic immiscibility of Cu and Fe. Our focus in this study lies on investigating the combined effects of parameters such as laser power, scanning speed, and scanning spacing on porous Cu precursors and porous Cu pore structures in the SLM technique, utilizing Taguchi's experimental method. The goal is to propose a design strategy for the rapid and high-precision fabrication of bulk ultrafine crystalline nanoporous metals. These metals hold promise for various functional applications and can be utilized in the preparation of porous metals across different systems.
10.1007-s11595-025-3152-2	-1		By applying the rapid solidification technique of deep undercooling, Cu65Ni35 and Cu60Ni40 alloys achieved maximum undercoolings of 284 and 222 K, respectively. Microstructural images captured reveal grain refinement in both alloys across both large and small undercooling ranges. High-speed photography was used to analyze the relationship between solidification front morphology and undercooling, showing that dendrite remelting and fragmentation caused grain refinement under small undercooling, while stress-induced recrystallization is responsible under large undercooling. Microhardness testing further demonstrates a sudden drop in microhardness near the critical undercooling point, providing evidence for grain refinement due to recrystallization in large undercooling tissues.
10.1007-s11661-000-0194-z	-1		This article reviews expressions to quantify the thermal creep and fatigue lifetime for four copper alloys: Cu-Ag-P, Cu-Cr-Zr, Cu-Ni-Be, and Cu-Al2O3. These property models are needed to simulate the mechanical behavior of structures with copper components, which are subjected to high heat-flux and fatigue loading conditions, such as molds for the continuous casting of steel and the first wall in a fusion reactor. Then, measurements of four-point bending fatigue tests were conducted on two-layered specimens of copper alloy and stainless steel, and thermal ratchetting behavior was observed at 250 degrees C. The test specimens were modeled with a two-dimensional elastic-plastic-creep finite-element model using the ABAQUS software. To match the measurements, a primary thermal-creep law was developed for Cu-0.28 pet Al2O3 for stress levels up to 500 MPa and strain rates from 10(-8) to 10(-2) s(-1). Specifically, (epsilon) over dot (s(-1)) =1.43 x 10(10) exp (-197,000/8.31 T(K)) (sigma(MPa))(2.5) (t(s))(-0.9).
10.1007-s11661-000-0270-4	4	transformation; martensite; martensitic; phase; shape; beta; memory; shape memory; temperature; temperatures; martensitic transformation; gamma; transformation temperatures; effect; thermal	Shape memory alloys exhibit superelasticity when they are deformed in a temperature range where the thermoelastic martensite forms on application of a strain. The martensite persists upon removal of the applied strain, and the alloy recovers the original shape on heating over the reverse-transformation temperature after removing the strain. The beta-phase CuZnAl alloys have beta-type superlattice in the parent case, and M9R or M18R martensites occur on quenching the alloys from the homogenization temperature. The basal plane of martensite is exposed to hexagonal distortion with martensitic transformation as well as the monoclinic distortion in the crystal structure, and splittings are observed in some selected diffraction-peak pairs due to the differences in atom sizes in lattice points. These pairs have a great importance as ordering criteria and satisfy a special relation between Miller indices. The present text reports the variation of the differences in interplane spacings (Delta d) between some selected planes upon the further aging at room temperature at which alloys are fully martensitic. The decrease of Delta d during the aging implies that the monoclinic distortion decreases. The mass increases are caused by the oxidation upon heating the alloys at high temperatures close to the betatizing temperature at free atmosphere.
10.1007-s11661-001-0023-z	16	wear; composite; composites; powders; milling; particles; powder; wt; sliding; friction; hardness; matrix; mechanical; surface; properties	The tribological properties of a centrifugally cast lead-free copper alloy (C90300), containing an average of 13 Vol pet graphite particles (5 mum), have been studied. Friction tests were carried out at three different loads of 44, 88, and 176 N using a pin-on-disk testing method for the base copper alloy and the copper-graphite composite against a 1045 steel disk counterface. The friction coefficient, temperature rise, and weightloss of the pin and disk were measured. To understand the wear mechanism, the. wear debris and the surfaces of the pin and the disk were analyzed before and after the tests, using scanning electron microscope (SEW and energy-dispersive X-ray (EDX) analysis. The friction coefficient of the copper-graphite pins was lower than that of the base-alloy pins for all applied loads, which was attributed to the presence of the graphite in the matrix. It was also observed that the presence of graphite in the matrix reduces the transfer of iron from the counterface to the pins, but enhances the transfer of materials from the pins to the counterface. The temperature rise in the counterface running against the base-alloy pins was larger than the temperature rise in the counterface running against the copper-graphite pins, both tested under similar conditions. In addition, the effect of element transfer on the friction coefficient, variations in the weight of the pins and the counterface, as well as the surface roughness, are attributed to the formation of a graphitic tribolayer on the surface of the copper-graphite pins. An isostrain model predicting the friction coefficient of the composites is proposed, which agrees well with the measurements in the present article as well as with measurements made by other investigators. ([10]).
10.1007-s11661-001-0109-7	6	grain; deformation; strain; strength; dislocation; cu-; tensile; size; ecap; grain size; sfe; ductility; hardening; high; stress	The role of stacking fault energy (SFE) in deformation twinning and work hardening was systematically studied in Cu (SFE similar to 78 ergs/cm(2)) and a series of Cu-Al solid-solution alloys (0.2, 2, 4, and 6 wt pet Al with SFE similar to 75, 25, 13, and 6 ergs/cm(2), respectively). The materials were deformed under quasi-static compression and at strain rates of similar to 1000/s in a Split-Hopkinson pressure bar (SHPB). The quasi-static flow curves of annealed 0.2 and 2 wt pet Al alloys were found to be representative of solid-solution strengthening and well described by the Hall-Fetch relation. The quasi-static flow curves of annealed 4 and 6 wt pet Al alloys showed additional strengthening at strains greater than 0.10. This additional strengthening was attributed to deformation twins and the presence of twins was confirmed by optical microscopy. The strengthening contribution of deformation twins was incorporated in a modified Hall-Fetch equation (using intertwin spacing as the effective grain size), and the calculated strength was in agreement with the observed quasi-static flow stresses. While the work-hardening rate of the low SFE Cu-AL alloys was found to be independent of the strain rate, the work-hardening rate of Cu and the high SFE Cu-Al alloys (low Al content) increased with increasing strain rate. The different trends in the dependence of work-hardening rate on strain rate was attributed to the difference in the ease of cross-slip (and, hence, the ease of dynamic recovery) in Cu and Cu-Al alloys.
10.1007-s11661-001-0130-x	6	grain; deformation; strain; strength; dislocation; cu-; tensile; size; ecap; grain size; sfe; ductility; hardening; high; stress	Microstructural refinement to further improve the strength and stability of high-strength high-conductivity Cu-Cr-Nb alloys was attained by mechanical milling (MM). Mechanically milled Cu-4Cr-2Nb and Cu-8Cr-2Nb exhibited an increase in hot-pressed Vickers hardness of 122 and 96 pct, respectively. Mechanical milling produced a corresponding decrease in electrical conductivity of similar to 33 pct for both alloys. The increase in hardness was more due to Cu grain-size refinement than to second-phase particle-size refinement. The drop in conductivity was due to second-phase particle-size refinement, which both increased particle/matrix interfacial area and solute solubility. Mechanically processed Cu-4Cr-2Nb displayed an enhanced thermal stability. Hot-pressed 4-hour milled Cu-4Cr-2Nb experienced a 30 pct increase in conductivity with only a 22 pct drop in hardness when annealed at 1273 K for 50 hours. Such changes were largely due to an increase in dispersed-particle size (i.e., a decrease in solute and interfacial electron scattering) and Cu pain size (reduced Hall-Fetch effect), respectively. The optimum hardness and conductivity combination was found in 4-hour milled and hot-pressed Cu-4Cr-2Nb material.
10.1007-s11661-002-0173-7	12	thermodynamic; ternary; phase; data; experimental; equilibria; phase equilibria; liquid; binary; experimental data; calculated; phases; literature; model; calphad	Thermodynamic optimization of the Cu-Al-Sn system is made using classical thermodynamic models for describing the properties of the individual phases of the system. The optimization is limited to the copper-rich corner of the system, the gamma phase of the Cu-Al and Cu-Sn systems being the remotest phase included in the analysis. The data of the pure components and the binary systems are taken from the previously assessed Scientific Group Thermodata Europe (SGTE)-compatible descriptions, although a slight reoptimization of data is first made for the bee, fee, and gamma phases of the Cu-Al system and for the liquid and gamma phases of the Cu-Sn system. Next, ternary thermodynamic data are optimized for the ternary Cu-Al-Sn system using the experimental phase-equilibrium data of the literature. The results of the optimization are presented by comparing the original, experimental data with the calculations, and reasonable agreement is demonstrated.
10.1007-s11661-002-0228-9	-1		The microstructural changes during mechanical alloying and subsequent hot pressing of Cu, Ti, and B powder mixtures were studied using scanning electron microscopy, X-ray diffraction, differential thermal analysis, and electron microprobe analysis. In particular, the changes in the Cu grain size, lattice parameter, and lattice strain of the powder mixtures and the formation of new phases (TiCu4 during mechanical alloying and TiB2 during hot pressing) were investigated. The mechanism of the in-situ formation of TiB2 particles in the resultant copper composite was also studied.
10.1007-s11661-002-0267-2	-1		A significant improvement in the degree of superelasticity in Cu-Al-Mn ductile polycrystalline alloys has been achieved through the addition of Ni and control of the recrystallization texture by thermomechanical processing, which contain the annealing in the fcc (alpha) + bcc (beta) two-phase region, followed by heavy cold reductions of over 60 pct. The addition of Ni to the Cu-Al-Mn alloys shows a drastic effect on the formation of the strong {112} <110> recrystallization texture. Superelastic strains on the order of 7 pct, 3 times larger than those in other Cu-based shape-memory alloys (SMAs), have been realized in the textured Cu-Al-Mn-Ni alloys. The superelastic strains obtainable in the textured Cu-based SMAs are on a par with those attainable in Ni-Ti-based alloys.
10.1007-s11661-002-0379-8	4	transformation; martensite; martensitic; phase; shape; beta; memory; shape memory; temperature; temperatures; martensitic transformation; gamma; transformation temperatures; effect; thermal	The martensitic transformation temperatures and the types of martensitic phases have been determined in a wide concentration range of technological interest for Cu-Al-Ni shape-memory alloys (SMAs) A stability diagram of martensitic phases as a function of alloy concentration has been determined. It is found that when the aluminum, content increases, the transformation changes from beta(3) double right arrow beta'(3) to beta(3) double right arrow gamma'(3), with an intermediate concentration range where both martensites coexist due to a beta(3) double right arrow gamma'(3) + beta'(3) transformation. On the other hand, an increase of nickel content stabilizes the martensite beta'(3), changing from a mixed beta(3) == gamma'(3) + beta'(3) to a single beta(3) double right arrow beta'(3) transformation. Furthermore, linear relationships between M-s and Al and Ni concentrations have been obtained for all types of martensitic phases.
10.1007-s11661-003-0086-0	-1		In the as-quenched condition, the microstructure of the Cu-14.2 wt pct Al-7.8 wt pet Ni alloy was D0(3) phase containing extremely fine L-J precipitates with two variants. The L-J precipitate has an orthorhombic structure with lattice parameters a = 0.413 nm, b = 0.254 nm and c = 0.728 nm, which was a new phase found firstly by the present workers. The orientation relationship between the L-J phase and the matrix is (100)(L-J)//(011)(m), (010)(L-J)//(111) and (001)(L-J)//(211)(m). The rotation axis and rotation angle between two variants of the L-J phase are [021] and 90 deg. When the alloy was aged at 500 degreesC for short times and then quenched, gamma(2) particles started to precipitate within the D0(3) matrix at the aging temperature and the remaining D0(3) matrix would transform to gamma(1)' martensite during quenching. This is similar to that observed by other workers in a Cu-14Al-4Ni alloy. However, when the alloy was aged at 500 degreesC for longer times, the remaining D0(3) matrix would transform to a mixture of (B2 + alpha) phases. This feature has never been observed by other workers in the Cu-Al-Ni alloys.
10.1007-s11661-003-0125-x	-1		The kinetics of breakdown of Cu-Ag polycrystalline multilayers during aging at elevated temperatures was investigated. Microlaminates with Cu:Ag layer thicknesses of 2:2, 1:4, 4:1, and 4:0.1 mum were aged for 10 minutes to 192 hours (t), at temperatures ranging from 700 to 900 K. The as-deposited microlaminates had a fine-grained columnar microstructure with well-defined interfaces. Upon annealing, the morphology evolved over three tithe regimes. In the first regime, the grains in each phase grew quickly to an apparent terminal size, which depended on both the layer thickness and annealing temperature. Next, grooves formed at the intersections of grain boundaries and layer interfaces and grew with a t(0.25) dependence. The groove growth appeared to be independent of layer thickness and was approximately equal in Cu and Ag. The microlaminates started to break down in the third regime, as grain-boundary grooves on opposite sides of a layer bridged its thickness. Models for grain growth and grooving in thin films were modified for multilayer microlaminates and were shown to fit the experimental data reasonably well. This suggests that the terminal grain size is reached when groove drag overcomes the capillary forces driving grain growth, and that grooving kinetics are dominated by interfacial diffusion.
10.1007-s11661-003-0262-2	-1		Electrode degradation has been studied during series-mode microresistance welding of thin-sheet nickel-plated steel to nickel. The main focus of the study was the effects of a TiC metal matrix composite coating. The results indicated that electrode degradation was caused predominantly by material loss due to pitting (as a result of the fracturing of local bonds between the electrode tip and sheet) and also by microscopic extrusion or plastic deformation (as a result of the softening of electrode tip regions). The composite coating improved tip life by about 70 pct, mainly because the TiC particles contained in the coating discouraged local bonding between the electrodes and sheets, and probably also improved the resistance to surface extrusion. It was also found that the use of an oxide-dispersion-strengthened copper alloy (Cu-Al2O3) improved tip life by only about 15 pct compared to the conventional precipitation-strengthened Cu-Cr-Zr electrode alloy.
10.1007-s11661-004-0065-0	-1		The solidification of undercooled Cu-x wt pct Sn (x = 1, 2, 3, or 4) alloys has been studied by a melt-encasement (fluxing) technique. It was found that below undercoolings of DeltaT approximate to 90 K, the preferred dendrite growth orientation in each of these alloys was along the <111> direction: moreover, the 2 and 3 wt pct Sn alloys also displayed evidence of twinned growth . Above DeltaT approximate to 90 K, the preferred growth direction returned to the more usual <100> orientation.
10.1007-s11661-004-0196-3	-1		Ti57-xCu15Ni14Sn4+xNb10 (x = 0, 5, or 10) alloys were prepared by copper mold casting. At Sn = 4 at. pet, a dendrite/ultrafine-structured multicomponent alloy was obtained, which exhibits 1271 MPa yield strength, 77 GPa Young's modulus, and 2 pet plasticity at room temperature for 3-mm-diameter samples. The cooling rate significantly affects the as-east microstructure and the mechanical properties. For 5-mm-diameter samples, the alloy exhibits 1226 MPa yield strength, 63 GPa Young's modulus, and 2.5 pet plasticity. At Sri = 9 at. pet, Ti-, Sn-, and Nb-rich particles precipitate primarily. This near-hypereutectic alloy composition leads to the precipitation of intermetallics, which deteriorate the mechanical properties and result in the coexistence of ductile and brittle fracture mechanisms. At Sn = 14 at. pet, the alloy composition is completely in the intermetallic region, thus inducing the formation of Ti2Cu, Ti2Ni, and Ti3Sn intermetallics. The alloy becomes very brittle because the intermetallic compounds dominate the fracture process.
10.1007-s11661-004-0357-4	6	grain; deformation; strain; strength; dislocation; cu-; tensile; size; ecap; grain size; sfe; ductility; hardening; high; stress	In the present study, the tensile anisotropy of age-hardened Cu-6Ni-2Mn-2Sn-2Al, Cu-6Ni-2Mn-2Sn-2Al, and Cu-6Ni-2Mn-5Al alloy sheets, either perpendicular or parallel to the rolling direction, was examined. It was found that age-hardened Cu-Ni-Mn-Sn-Al alloys have higher tensile strength along the T orientation than L orientation at high rolling ratios. Such a trend was most notable in the high Al containing Cu-6Ni-2Mn-5Al alloy among the alloys studied. At high rolling ratios, well-developed deformation bandlike structures were observed to be mostly aligned perpendicular to the rolling direction for each alloy. These deformation bandlike structures appeared to be responsible for the higher tensile strength along the T orientation. The transmission electron microscopy (TEM) examination demonstrated that the deformation bandlike structures consisted of tangled dislocation networks, which were further thickened with the addition of Al or the reduction of Sn. The stacking fault energy (SFE) of Al and Sn, as related to the ease of cross-slip, is believed to be responsible for the present observation.
10.1007-s11661-005-0242-9	-1		Normal spectral emissivities of solid Cu-Ni alloys were determined using an ellipsometer combined with an electric furnace for a wavelength of 632.8 nm in the temperature ranges between 800 K and the respective solidus temperatures. The emissivities of the alloys had slightly positive temperature coefficients and seemed to be on quadratic functions of the atomic fraction of nickel. Thermal radiation of transition metals in the visible and near-infrared regions is generally considered to stem from the excitation-relaxation processes of free electrons and inner shell electrons, i.e., electrons at the d-like levels in the Cu-Ni system. Thus, the contribution from the former to the emissivities has been calculated on the basis of the free-electron model with damping. The difference between measured and calculated values corresponds to the contribution from inner shell electrons, which has been found to depend strongly upon neither temperature nor chemical composition in the range of the nickel atomic fraction, X-Ni > 0.2. On the basis of these findings, an empirical prediction equation for the emissivity at 632.8 nm for solid Cu-Ni alloys has been proposed: this equation applies at temperatures higher than 800 K in the range of X-Ni > 0.2 and can predict emissivity with an uncertainty less than 13 pct.
10.1007-s11661-005-0316-8	11	glass; bulk; metallic; bulk metallic; gfa; bmg; glassy; metallic glass; ability; bulk metallic glass; amorphous; addition; crystallization; mm; glass-forming	We report in this article that strip-shaped amorphous samples with thicknesses from 0.5 to 2 nun were successfully synthesized for binary Cu-Hf alloys containing 60 to 68 at. pct Cu by the traditional copper mold casting method. The best glass former Cu66Hf34 with casting thickness up to 2 turn has an undercooled liquid region (DeltaT = T-x-T-g, where T-g is the glass transition temperature and T-x is the onset temperature of the first crystallization event) of 51 K, which is somewhat narrow compared with other neighboring 2 alloys in the same system. The bulk glassy Cu66Hf34 alloy exhibits Vicker's Hardness (H-v) similar to 779 kg/mm(2), Young's modulus similar to108 GPa, fracture strength similar to2.1 GPa, and an almost constant elastic elongation similar to1.8 pct upon compression. The discovery of Cu66Hf34 as a bulk glass confirms the existence of rather simple bulk-glass-forming metallic systems. Moreover, the present Cu-Hf alloys may be the highest copper content bulk metallic glasses reported to date, to the best of our knowledge.
10.1007-s11661-006-0154-3	4	transformation; martensite; martensitic; phase; shape; beta; memory; shape memory; temperature; temperatures; martensitic transformation; gamma; transformation temperatures; effect; thermal	The phase transformations during fabrication and aging after cold deformation in three polychrystalline copper alloys of the Cu-Al-Ni system with shape memory effect (SME) were characterized. Some phase transformations were identified with clear repercussion in their mechanical properties during thermomechanical treatments. Around 430 degrees C, mutual effects of beta-phase recrystallization and precipitation of gamma(2) and NiAl phases were observed. Close to 600 degrees C the dissolution of phase alpha was observed, beginning transformation into 6 phase process. Brittle phases such as gamma(2) and NiAl began to precipitate during a short exposure time at 380 degrees C, 585 degrees C, 600 degrees C, and 700 degrees C temperatures. The phase transformations were intensified due to the plastic deformation that acted as a driving force for the diffusion processes. The introduction of chemical elements inhibited the grain growth and increased the structural disorder generating an elevation in the hardness property.
10.1007-s11661-006-0166-z	-1		In this work, differential scanning calorimetry (DSC) and microstructural analysis were used to study the transient-liquid-phase sintering (TLPS) of a Cu-Sn-Bi powder mixture. During sintering, the liquid C phase shifts from a Sn-rich (i.e., similar to 90 wt pct Sn) to a Bi-rich (i.e., > 78 wt pct Bi) composition. In addition, the presence of Bi creates two melting events: a Sn:Bi eutectic reaction at 139 degrees C and a reaction involving the melting of (Bi) at 191 degrees C. The Sn:Bi eutectic melting event was fully transient. The melting event at 191 degrees C was consistent with the formation of a terminal Bi-rich liquid phase. The rate of compositional shift toward this terminal liquid phase at 260 degrees C was dependent on the rate of the reaction of the Sri with the Cu powder to form intermetallic phases. For mixtures made with medium and fine Cu powder, the terminal Bi-rich composition was reached after isothermal hold times of 20 and 15 minutes, respectively. This resulted in a new melting point for the mixture of 191 degrees C. For coarse Cu powders, the rate of the compositional shift toward a Bi-rich composition was much slower. The liquid phase remained at a hypoeutectic Sn-Bi composition estimated at 80 wt pet Sri, while the mixture maintained a melting point of 139 degrees C.
10.1007-s11661-007-9291-6	11	glass; bulk; metallic; bulk metallic; gfa; bmg; glassy; metallic glass; ability; bulk metallic glass; amorphous; addition; crystallization; mm; glass-forming	The microstructure and mechanical properties of Cu(50)Zr(50-x)Ti(x) (2.5 <= x <= 7.5) glass matrix composites have been investigated. The presence of austenitic (Pm-3m)/martensitic phases (P2(1)/m and Cm) enhances the plastic deformability significantly. These composites show high yield strength up to 1753 MPa and large plastic strain over 15 pct. Their high strength scales with the volume fraction of glassy matrix and crystalline phase. When the austenitic phase forms instead of the martensite, the work hardening of the composite material increases.
10.1007-s11661-007-9325-0	-1		Microstructure and mechanical properties of Cu-based amorphous alloy/copper composites consolidated by spark plasma sintering (SPS) equipment were investigated in this study. Amorphous alloy powders were mixed with 10 to 40 Vol pct of pure Cu powders and were consolidated at 460 degrees C for 0.5 minute under 300 or 700 MPa. The consolidated composites contained Cu particles homogeneously distributed in the amorphous matrix, and showed a considerable plastic strain, whereas their compressive strength was lower than that of the monolithic amorphous alloys. The compressive strength and plastic strain of the composites consolidated under 700 MPa showed 10 to 20 pet and 2 times increases, respectively, over those of the composites consolidated under 300 MPa. The increase in consolidation pressure could play a role in sufficient bonding between prior amorphous powders, in preventing micropores, and in suppressing the crystallization, thereby leading to the successful consolidation of the high-quality composites. These findings suggested that the composites consolidated by the SPS presented new possibilities of application to structural materials or parts requiring excellent mechanical properties and large sizes.
10.1007-s11661-007-9337-9	-1		The binary Cu-Nb system is rather interesting, because Cu and Nb are virtually immiscible in the solid state, exhibit a relatively strong clustering (phase separating) tendency in the liquid state, and therefore can only be alloyed in a highly metastable form, for example, by vapor quenching techniques such as sputtering. In this article, metastable amorphous Cu-Nb alloy thin films with nominal compositions of Cu-45 at. pct Nb have been deposited by magnetron cosputtering. The amorphous phase in these thin films exhibits nanoscale phase separation in the as-deposited condition. The early stages of devitrification of this amorphous phase have been investigated using three-dimensional atom probe tomography coupled with transmission electron microscopy. The results indicate that devitrification of this phase-separated amorphous phase is initiated by the formation of nanoscale fcc Cu-rich grains uniformly distributed in the amorphous matrix. These nanoscale fcc Cu-rich grains are often faulted and appear to retain some Nb supersaturation. The role of the nanoscale phase separation in the as-deposited amorphous film on the subsequent devitrification is discussed in the context of free energy-composition plots for this system.
10.1007-s11661-007-9354-8	-1		In the present investigation, thermodynamic and topological concepts have been used together to understand the formation of bulk metallic glasses. The article attempts to develop a parameter that combines chemical mixing enthalpy (Delta H-chem), mismatch entropy normalized by Boltzmann constant (Delta S-sigma/k(B)), and configurational entropy (Delta S-config/R), which can be effectively used to identify the best bulk glass forming compositions in multicomponent systems. The Delta H-chem for multicomponent systems has been calculated by extending the Miedema's macroscopic model, and Delta S-sigma /k(B) was obtained from Mansoori's approach . The iso-Delta H-chem, iso-Delta S-sigma /k(B), and iso-Delta S-config/R contours have been developed. The product of Delta H-chem and Delta S-sigma /k(B) in the Delta S-config/R range of 0.9 to 1.0 can be correlated strongly to glass forming ability. This has been demonstrated in the case of the quaternary Cu-Zr-Ti-Ni bulk glass forming system to determine the bulk metallic glass forming compositions. Mechanical alloying is used to prepare the bulk amorphous powder at the compositions predicted by the model in order to validate the model.
10.1007-s11661-007-9372-6	-1		The oxidation behavior of the Cu47.5Zr47.5Al5 (Cu-3) and Cu47Ti34Zr11Ni8 (Cu4) bulk metallic glasses (BMGs) was studied over the temperature range of 400 degrees C to 500 degrees C in dry air. The oxidation kinetics of both alloys generally followed a multistage parabolic-rate law, and the steady-state parabolic-rate constants (k(p) values) fluctuated with temperature for the Cu3 BMG, but increased with increasing temperature for the Cu4 BMG. The scales formed on the BMGs were strongly dependent on the temperature and alloy composition, and were composed primarily of tetragonal-ZrO2 (t-ZrO2) and minor amounts of Al2O3, Cu2O, and CuO at 400 degrees C for the Cu3 BMG, while the monoclinic-ZrO2 (m-ZrO2) phase is present at T ! 425 degrees C, and the Cu2O phase is absent at 500 degrees C. Conversely, the scales formed on the Cu4 BMG consisted exclusively of CuO at 400 degrees C, while minor amounts of t-ZrO2, TiO2, and ZrTiO4 formed at 425 degrees C to 450 degrees C, and TiO was also detected at higher temperatures. It was found that both amorphous Cu3 and Cu4 substrates transformed into different crystalline phases, and were strongly dependent on temperature and duration of time.
10.1007-s11661-008-9466-9	-1		The effects of Ti addition on the liquid-phase separation of Cu71Cr29 alloy have been investigated. It is revealed that Ti addition can partly suppress the liquid-phase separation of the alloy melts, resulting in refining of Cr-rich particles formed after liquid-phase separation during rapid cooling. Nanoscaled Cr2Ti and Cu4Ti phases precipitate in the annealed Cu-Cr-Ti ribbons when Ti content attains 2.5 pct. The thermodynamic analyses indicate that the large positive mixing heat between Cu and Cr is reduced by the addition of Ti, leading to the liquid-phase separation occurring at a lower temperature and being driven by a smaller force. However, more Cr and Ti dissolve in Cu solid solution when Ti content is more than 3 pct, and as a result, the electrical resistivity of the ribbons is increased sharply.
10.1007-s11661-009-0019-7	-1		Cu-10Cr-3Ag (wt pct) alloy with nanocrystalline Al2O3 dispersion was prepared by mechanical alloying and consolidated by high pressure sintering at different temperatures. Characterization by X-ray diffraction and scanning electron microscopy or transmission electron microscopy shows the formation of nanocrystalline matrix grains of about 40 nm after 25 hours of milling with nanometric (<20 nm) Al2O3 particles dispersed in it. After consolidation by high pressure sintering (8 GPa at 400 degrees C to 800 degrees C), the dispersoids retain their ultrafine size and uniform distribution, while the alloyed matrix undergoes significant grain growth . The hardness and wear resistance of the pellets increase significantly with the addition of nano-Al2O3 particles. The electrical conductivity of the pellets without and with nano-Al2O3 dispersion is about 30 pct IACS (international annealing copper standard) and 25 pct IACS, respectively. Thus, mechanical alloying followed by high pressure sintering seems a potential route for developing nano-Al2O3 dispersed Cu-Cr-Ag alloy for heavy duty electrical contact.
10.1007-s11661-010-0281-8	16	wear; composite; composites; powders; milling; particles; powder; wt; sliding; friction; hardness; matrix; mechanical; surface; properties	In this article, a novel method has been used to prepare a copper matrix nanocomposite containing Cu-10 wt pct Cr-10 wt pct Al2O3 by heat treatment of the mechanically activated Cu, Al, and Cr2O3 powder mixture. Structural evolutions were investigated using the X-ray diffraction (XRD) technique. The microstructure of samples was examined using scanning electron microscopy (SEM). It was found that during the milling process, Cu(Al) solid solution and Cu9Al4 phase were formed as the intermediate products, and therefore, Al activity was decreased. Hence, the reduction of Cr2O3 with Al was prevented during the ball milling stage. Further heat treatment carried out under argon atmosphere at 900 A degrees C for 8 hours resulted in completion of Cr2O3 reduction by Al.
10.1007-s11661-010-0346-8	-1		Using a single-mode 915-MHz microwave applicator equipped with a ceramic pressing unit, we processed the gas-atomized Cu50Zr45Al5 metallic glassy alloy powder blended with Sn powder of various contents in a separated magnetic (H-) field maximum. The blended powders were well heated in H-field. Bulk Cu50Zr45Al5 metallic glass matrix composites were produced with an applied pressure of 5 MPa. As a secondary phase, the Sn particle promoted the densification of the sintered samples.
10.1007-s11661-010-0432-y	-1		An attempt was made to study the effect of Mn addition on the formation of supersaturated solid solution of Co and Fe in Cu during ball milling and precipitation of the solute-rich phases during subsequent annealing of the ball-milled product. It is demonstrated that the addition of Mn in the ternary CuFeCo powder blend enhances the metastable solubility of Fe and Co in Cu and facilitates the formation of the nanocrystalline supersaturated single-phase solid solution. Field emission-scanning electron microscopy (FE-SEM) also revealed notable influence of Mn on the morphological evolution of the ball-milled and annealed alloy powders. X-ray diffraction (XRD) analysis revealed that the FeCo phase having the bcc Bravais lattice forms after annealing at and above 620 K ( 350 degrees C) in both alloys. Estimation of magnetic properties showed that Mn addition in the CuFeCo alloy improved the coercivity, remanence, and magnetic saturation.
10.1007-s11661-010-0589-4	-1		For the first time, we report here that high purity nanocrystalline Cu and Cu-10 wt pct Pb alloys can be densified with more than 90 pct theoretical density at a low temperature of 623 K (350 A degrees C) using spark plasma sintering (SPS) in argon atmosphere at a pressure of 100 MPa. Scanning electron microscopy (SEM) analysis indicates that molten Pb particles travel through Cu grain boundaries, delineating a flowlike pattern in the microstructure. An extensive transmission electron microscopy (TEM) analysis of the ultrafine scale microstructure reveals partial wetting of Cu by liquid Pb as well as entrapment of Pb particles within the Cu matrix. The sintering kinetics and microstructural evolution are discussed in reference to the intrinsic characteristics of SPS as well as phase equilibria in the Cu-Pb system. An important result is that high hardness of around 2 GPa is measured in the Cu-10 wt pct Pb nanostructured alloy, SPS at 573 K to 623 K (300 A degrees C to 350 A degrees C).
10.1007-s11661-010-0594-7	4	transformation; martensite; martensitic; phase; shape; beta; memory; shape memory; temperature; temperatures; martensitic transformation; gamma; transformation temperatures; effect; thermal	The kinetics of the precipitation of Co from a supersaturated solid solution of Cu-0.95 at. pct Co was investigated by isochronal annealing applying differential scanning calorimetry (DSC) with heating rates in the range 5 to 20 K min(-1). The corresponding microstructural evolution was investigated by high-resolution transmission electron microscopy (HRTEM) in combination with electron energy loss spectroscopy (EELS). Upon isochronal annealing, spherical Co precipitates of fcc crystal structure form. Kinetic analysis by fitting of a modular phase transformation model to, simultaneously, all DSC curves of variable heating rate measured for Cu-0.95 at. pct Co showed that the precipitation-process mechanism can be described within the framework of this general phase transformation model by continuous nucleation and diffusion-controlled growth . By introducing additional microstructural information (here, the precipitate-particle density), for the first time, values for the separate activation energies of nucleation and growth could be deduced from the transformation kinetics.
10.1007-s11661-011-0637-8	6	grain; deformation; strain; strength; dislocation; cu-; tensile; size; ecap; grain size; sfe; ductility; hardening; high; stress	To improve the balance of the electrical conductivity and mechanical strength for dilute Cu-Ti alloys by aging in a hydrogen atmosphere, the influence of aging temperature ranging from 673 K to 773 K (400 A degrees C to 500 A degrees C) on the properties of Cu-3 at. pct Ti alloy was studied. The Vickers hardness increases steadily with aging time and starts to fall at 3 hours at 773 K (500 A degrees C), 10 hours at 723 K (450 A degrees C), or over 620 hours at 673 K (400 A degrees C), which is the same as the case of conventional aging in vacuum. The maximum hardness increases from 220 to 236 with the decrease of aging temperature, which is slightly lower than aging at the same temperature in vacuum. The electrical conductivity at the maximum hardness also increases from 18 to 32 pct of pure copper with the decrease of the temperature, which is enhanced by a factor of 1.3 to 1.5 in comparison to aging in vacuum. Thus, aging at 673 K (400 A degrees C) in a hydrogen atmosphere renders fairly good balance of strength and conductivity, although it takes nearly a month to achieve. The microstructural changes during aging were examined by transmission electron microscopy (TEM) and atom-probe tomography (APT), and it was confirmed that precipitation of the Cu4Ti phase occurs first and then particles of TiH2 form as the third phase, thereby efficiently removing the Ti solutes in the matrix.
10.1007-s11661-011-0728-6	-1		The present work deals with the preparation of near-full density Cu-Al-Ni shape memory alloy (SMA) strips from argon-atomized prealloyed powder via a powder metallurgy (PM) route comprising cold die compaction to prepare powder preforms, sintering, and hot densification rolling of unsheathed sintered powder preforms under protective atmosphere at 1273 K (1000 degrees C). It has been shown that argon-atomized spherical Cu-Al-Ni SMA powder consisted of very fine equiaxed grains and no appreciable grain growth occurred during sintering at 1273 K (1000 degrees C). It also has been shown that no appreciable densification occurred during sintering, and densification was primarily achieved by hot rolling. The densification behavior of the sintered powder preforms during hot rolling was discussed. The hot-rolled Cu-Al-Ni strips were heat-treated at 1223 K (950 degrees C) for 60 minutes and water quenched. The heat-treated strips consisted of equiaxed grains with average size approximately 90 mu m. The heat-treated Cu-Al-Ni SMA strips consisted of self-accommodated beta(1)' martensite primarily, and showed smooth beta(1) double right arrow beta(1)' transformation behavior coupled with a very low hysteresis (approximate to 25 K (25 degrees C)). The heat-treated strips exhibited an extremely good combination of mechanical properties with fracture strength of 530 MPa and 12.3 pct fracture strain. The mode of fracture in the finished strip was primarily void-coalescence-type ductile together with some brittle transgranular type. The shape memory tests showed almost 100 pct one-way shape recovery after 100 bending-unconstrained heating cycles at 4 pct applied prestrain, exhibiting good stability of Cu-Al-Ni strips under thermomechanical actuation cycling. The two-way shape memory strain was found approximately 0.45 pct after 15 training cycles at 4 pct training strain.
10.1007-s11661-011-0988-1	11	glass; bulk; metallic; bulk metallic; gfa; bmg; glassy; metallic glass; ability; bulk metallic glass; amorphous; addition; crystallization; mm; glass-forming	Cu-based Cu-Zr-Al metallic glass samples with diameters of more than 10 mm could be produced in a composition range of 45 to 52 (at. pct) Cu, 41 to 47 at. pct Zr, and 6 to 10 at. pct Al by a copper mold casting method. The best glass-forming ability was obtained for the Cu47Zr45Al8 alloy, and the glassy sample with a diameter of 15 mm was fabricated. The minor addition of Ag or Dy can enhance the glass-forming ability of the Cu47Zr45Al8 alloy, which decreases the liquidus temperatures, leading to increase in the reduced glass transition temperature. Fully glassy samples with diameters up to 20 mm were obtained for a (Cu0.47Zr0.45Al0.08)(98)Dy-2 alloy.
10.1007-s11661-011-1065-5	-1		Amorphous solid-solution Cu75Hf20Dy05, which undergoes devitrification without changing composition either locally or globally, was used to examine the effects of structural ordering on corrosion properties in the absence of any accompanying chemical partitioning. Melt spun amorphous Cu75Hf20Dy05 undergoes single-phase devitrification to a Cu51Hf14 phase. The difference in corrosion behavior between these two structures was explored in hydrofluoric acid solutions where preferential dissolution of hafnium occurred. Preferential Hf dissolution occurred more readily in the amorphous alloy compared with its crystalline counterpart. Remaining copper reorganized to form a face-centered cubic (fcc) nanostructure in both conditions, but this process occurred quickly in the amorphous state and more slowly in the crystalline variant. A uniform, nanoporous Cu sponge structure, with a pore diameter of approximately 10 nm, formed after dissolution in the amorphous state. A less uniform, nanoporous structure developed more slowly when occurring from the crystalline state. These differences were traced to the effects of ordering on both dissolution and surface diffusion.
10.1007-s11661-012-1081-0	-1		The current work describes the experimental results related to the successful preparation of fine-grained, Cu-Al-Ni, high-temperature shape-memory alloy (SMA) strips from elemental Cu, Al, and Ni powders via a novel powder metallurgy (P/M) processing approach . This route consists of short time period ball milling of elemental powder mixture, preform preparation from milled powder, sintering of preforms, hot-densification rolling of unsheathed sintered powder preforms under protective atmosphere, and postconsolidation homogenization treatment of the hot-rolled strips. It has been shown that it is possible to prepare chemically homogeneous Cu-Al-Ni SMA strips consisting of equiaxed grains of average size approximately 6 mu m via the current processing approach . It also has been shown that fine-grained microstructure in the finished Cu-Al-Ni SMA strips resulted from the pinning effect of nanosized alumina particles present on the grain boundaries. The finished SMA strips were almost fully martensitic in nature, consisting of a mixture of-and -type martensites. The Cu-Al-Ni SMA strips had 677 MPa average fracture strength, coupled with 13 pct average fracture strain. The fractured surfaces of the specimens exhibited primarily dimpled ductile type of fracture, together with some transgranular mode of fracture. The Cu-Al-Ni strips exhibited an almost 100 pct one-way shape recovery after bending followed by unconstrained heating at 1, 2, and 4 pct applied deformation prestrain. The two-way shape-memory strain was found approximately 0.35 pct after 15 training cycles at 4 pct applied training prestrain.
10.1007-s11661-012-1136-2	-1		A phase-field model is proposed for phase transformations in glass-forming alloys. The glass transition is introduced as a structural relaxation, and the competition between the glass and crystalline phases is investigated. The simulations are performed for Cu-Zr alloys, employing thermodynamic and kinetic parameters derived from reported thermodynamic modeling and molecular dynamics simulation results,[1-3] respectively. Four distinct phase fields are treated with a multi-phase-field approach, representing the liquid/glass, Cu10Zr7, CuZr, and CuZr2 phases. In addition, a continuum-field method is applied to the liquid to accommodate the liquid-glass transformation. The combined phase-field approach is used to investigate the glass formation tendency, and critical cooling rates are estimated and compared with the reported experimental values.
10.1007-s11661-012-1396-x	16	wear; composite; composites; powders; milling; particles; powder; wt; sliding; friction; hardness; matrix; mechanical; surface; properties	Tungsten-copper composites with various copper nano-particles volume fractions were manufactured and examined. Tungsten-copper composites with 20 pct, 25 pct, and 30 pct volume fractions were mechanically mixed and sintered. spark plasma sintering (SPS) method was used for samples preparation at two different sintered temperatures 1273 K and 1373 K (1000 degrees C and 1100 degrees C). The effect of copper nano-particles on the bulk density, hardness, the coefficient of thermal expansion (CTE), electrical conductivity, and stress-strain behavior of the produced composites were studied. The hardness was found to decrease with the increase of the copper volume fraction in the composites. Conversely, the CTE and electrical conductivity increases with the increase of the copper volume fraction in the composites. Furthermore, the elastic modulus were extracted from tensile stress-strain behavior were found to increase with the increase of the copper volume fraction in the composites. Finally, the fracture surface roughness was studied using high resolution optical investigations and was noticeably higher with the increase of the copper volume fraction in the composites. DOI: 10.1007/s11661-012-1396-x (C) The Minerals, Metals & Materials Society and ASM International 2012
10.1007-s11661-013-1644-8	-1		Two copper-based alloys were considered, Cu-1 pct Cr and Cu-0.7 pct Cr-1 pct Si-2 pct Ni. The thermal, electrical, and mechanical properties of these alloys are given in the paper and compared to pure copper and steel. The role of aging and precipitation kinetics in hardening of the alloys is discussed based upon the developed model. Results of plastometric tests performed at various temperatures and various strain rates are presented. The effect of the initial microstructure on the flow stress was investigated. Rheologic models for the alloys were developed. A finite element (FE) model based on the Norton-Hoff visco-plastic flow rule was applied to the simulation of forging of the alloys. Analysis of the die wear for various processes of hot and cold forging is presented as well. A microstructure evolution model was implemented into the FE code, and the microstructure and mechanical properties of final products were predicted. Various variants of the manufacturing cycles were considered. These include different preheating schedules, hot forging, cold forging, and aging. All variants were simulated using the FE method and loads, die filling, tool wear, and mechanical properties of products were predicted. Three variants giving the best combination of forging parameters were selected and industrial trials were performed. The best manufacturing technology for the copper-based alloys is proposed. (C) The Author(s) 2013. This article is published with open access at Springerlink.com
10.1007-s11661-013-1824-6	-1		In the current investigation, nanocrystalline multicomponent high-entropy alloys (HEAs) have been synthesized in the Cu (x) Zn (y) Ti20Fe20Cr20 system (x/y = 1/0, 3/1, 1; and x + y = 40) by mechanical alloying and subsequently consolidated using spark plasma sintering (SPS) in argon atmosphere at a pressure of 50 MPa. A detailed X-ray diffraction and transmission electron microscopy study reveals the presence of both FCC copper solid-solution, (Cu)(ss) and BCC chromium solid-solution, (Cr)(ss) phases in both the mechanically alloyed powders as well as the sintered compacts. The phase formation and stability of the sintered multicomponent Cu (x) Zn (y) Ti20Fe20Cr20 with x/y = 3/1 and x + y = 40 pellet have been studied at different sintering temperatures, i.e., 873 K, 973 K, 1073 K, and 1173 K (600 A degrees C, 700 A degrees C, 800 A degrees C, and 900 A degrees C). The important findings include that high Vickers bulk hardness of around 6 GPa and relative density of around 95 pct reported in the Cu (x) Zn (y) Ti20Fe20Cr20 with x/y = 3/1 and x + y = 40 HEAs, SPSed at 1173 K (900 A degrees C). The formation, consolidation, and microstructural details are analyzed critically and discussed.
10.1007-s11661-013-1905-6	0	solidification; phase; magnetic; magnetic field; undercooling; field; liquid; separation; peritectic; immiscible; cu-; dendrite; phase separation; microstructure; primary	The microstructures of the Cu-35wt pct Fe alloys were investigated by melt-fluxing in combination with cyclic superheating and melt-spinning technique, respectively. Using the melt-fluxing with cyclic superheating technique, it was found that a complicated sub-microstructure formed in the separated minor phase, when the undercooling was 120 K (120 A degrees C). The processes of the phase transformation from a liquid state to room temperature for undercooled Cu-35wt pct Fe alloys were discussed, in order to understand the solidification with metastable liquid separation. By means of melt-spinning technique, it was indicated that the microstructure of solidification for Cu-35wt pct Fe alloys could be refined due to the high cooling rate.
10.1007-s11661-013-1993-3	-1		The use of Mg as an alloying element in copper alloys has largely been overlooked in scientific literature and technological applications. Its supposed tribological compatibility with iron makes it an interesting option to replace Pb in tribological alloys. This work describes the casting process of high-quality thin slabs of Cu-Mg-Sn alloys with different compositions by means of conventional methods. The resulting phases were analyzed using X-ray diffraction, scanning electron microscopy, optical microscopy, and energy dispersive X-ray spectroscopy techniques. Typical dendritic alpha-Cu, eutectic Cu2Mg(Sn) and eutectoid non-equilibrium microstructures were found. Tensile tests and Vickers microhardness show the excellent hardening capability of Mg as compared to other copper alloys in the as-cast condition. For some of the slabs and compositions, cold rolling reductions of over 95 pct have been easily achieved. Other compositions and slabs have failed during the deformation process. Failure analysis after cold rolling reveals that one cause for brittleness is the presence of casting defects such as micro-shrinkage and inclusions, which can be eliminated. However, for high Mg contents, a high volume fraction of the intermetallic phase provides a contiguous path for crack propagation through the connected interdendritic regions. (C) The Minerals, Metals & Materials Society and ASM International 2013
10.1007-s11661-013-2070-7	-1		This investigation has used flexural test to explore the effects of thermal treatments, i.e., high-temperature and cryogenic environments on the mechanical property of Al2O3 particulate-reinforced Cu metal matrix micro and nanocomposites in ex-situ and in-situ conditions. Cu-5 vol. pct Al2O3 micro (10 mu m)- and nanocomposites (< 50 nm) fabricated by powder metallurgy route were subjected to up-thermal shock cycle [193 K to 353 K (-80 A degrees C to 80 A degrees C)] and down-thermal shock cycle [353 K to 193 K (from 80 A degrees C to -80 A degrees C)] for different time periods followed by 3-point bend test. One batch of specimens (micro and nanocomposites) was conditioned at 353 K and 193 K (80 A degrees C and -80 A degrees C) separately followed by 3-point flexural test. High-temperature flexural test was performed at 373 K and 523 K (80 A degrees C and 250 A degrees C) on the micro and nanocomposites. All the fractured samples obtained after various thermal treatments were studied under scanning electron microscope (SEM). The development of thermal stresses quite often results in concentration of residual stresses at the particle/matrix interface eventually weakening it. Enhancement of flexural strength was recorded for down- as well as for up-thermal shock in microcomposites. The high-temperature flexural strengths of micro and nanocomposites are lower than those at ambient temperature. The amelioration and declination in mechanical properties as a consequence of thermal shock, thermal conditioning, and high-temperature flexural testing have been discussed in the light of fractography. (C) The Minerals, Metals & Materials Society and ASM International 2013
10.1007-s11661-013-2153-5	4	transformation; martensite; martensitic; phase; shape; beta; memory; shape memory; temperature; temperatures; martensitic transformation; gamma; transformation temperatures; effect; thermal	A monocrystalline alloy with nominal 82wt pctCu-13.7wt pctAl-4.2wt pctNi composition and exhibiting reversible martensitic transformation (RMT) was subjected to multiple heating and cooling cycles within the RMT range of critical temperatures. Both untreated and cyclic treated alloy samples were characterized by X-ray diffraction, optical microscopy, differential scanning calorimetry, and Vickers microhardness. The results indicated that the alloy presents a complex RMT behavior disclosing a sequence of transformation steps: beta (1) a dagger R and R a dagger beta'(1) + gamma'(1) as well as possible beta (1) a dagger beta'(1) and beta'(1) a dagger gamma'(1) direct reactions. The thermal cycling treatment inhibits the development of gamma'(1) martensite without much change in both the physical and microstructure characteristics. This suggests a good resistance of the alloy to irreversible structural changes.
10.1007-s11661-014-2353-7	6	grain; deformation; strain; strength; dislocation; cu-; tensile; size; ecap; grain size; sfe; ductility; hardening; high; stress	Dislocation structures in Cu-7 at. pct Al alloy single crystals cyclically deformed at different plastic strain amplitudes were investigated by transmission electron microscope (TEM) and compared with the results of Cu single crystals. It is found that the plastic strain amplitude gamma (pl) has an obvious effect on the slip deformation mode, and consequently on the cyclic hardening behavior of Cu-7 at. pct Al alloy single crystals with an intermediate stacking fault energy. For instance, a high slip planarity (i.e., only formation of planar-slip bands) contributes to the occurrence of a gentle cyclic hardening with a much lower saturation stress at a low gamma (pl) of 4.5 x 10(-4). A mixed planar/wavy-slip mode (e.g., persistent Luder's bands/wall-like microstructures) at an intermediate gamma (pl) of 2.2 x 10(-3) causes an obvious cyclic hardening up to a comparable saturation stress to that for the Cu single crystal. In contrast, the deformation mode is dominated by wavy slip (e.g., ill-defined dislocation cells and walls) at the highest gamma (pl) of 7.2 x 10(-3), causing that its cyclic hardening curve is quite similar to that for the Cu single crystal; in this case, a slightly higher saturation stress level than that for the Cu single crystal is reached due to the additional solid solution strengthening.
10.1007-s11661-014-2457-0	-1		Ni-B coating was prepared on the surface of graphite particles using the electroless plating method. The Ni-B coating was composed of spherical grains with average diameter of 80 nm. The phases of Ni-B coating were indexed as nanosized crystal Ni phase and amorphous Ni-B phase. Cu-Sn alloy/graphite composites with 0.5, 1.0, 1.5, and 2.0 wt pct graphite contents were synthesized by the powder metallurgy method. Ni-B coating improved the wettability and bonding strength between the Cu-Sn alloy and graphite. The composite with Ni-B coated graphite exhibited higher density, hardness, and compression strength compared with the composites with bare graphite. The crack propagation mechanism of the composites was also analyzed.
10.1007-s11661-014-2637-y	-1		In this study, the structural evolution of two nanostructured Cu-22 wt pct Ge (Cu-20 at. pct Ge) and Cu-26 wt pct Ge (Cu-24 at. pct Ge) alloys upon mechanical alloying (MA) with subsequent heat treatment was investigated, and the phase transitions were monitored by means of various characterization methods. The findings indicated that, when the MA process continued for some time, a nanocrystalline alpha-Cu(Ge) solid solution was formed, which partially transformed into an amorphous phase. Further MA processing for 20 hours led to the formation of a disordered nanometric epsilon-Cu3Ge intermetallic compound with a monoclinic crystal structure. Increased milling time subsequently led to the diminishing of the content of the amorphous phase which transformed into epsilon-Cu3Ge nanocrystals. Clearly, a nanocrystallization transformation occurred upon ball milling principally on account of the accumulated energy due to the heavy mechanical deformation. Crystallization was also seen to occur at 473 K (200 A degrees C) after annealing the MA-ed powders, leading to the formation of an ordered epsilon (1)-Cu3Ge intermetallic phase with an orthorhombic structure. The crystallographic relationships between the two disordered and ordered intermetallic phases were also discussed.
10.1007-s11661-014-2648-8	-1		Dendritic microsegregation was calculated using a Scheil-based solidification model for three alloys: 50.1 pct Cu-25.8 pct Ni-24.1 pct Mn; 42.4 pct Cu-25.4 pct Ni-32.2 pct Mn; 34.3 pct Cu-26.2 pct Ni-39.5 pct Mn. The dendritic microsegregation in these alloys was investigated using energy-dispersive X-ray analysis. It was shown by calculation and experimental methods that in all three alloys, the partition coefficient (k) of manganese passes through the value k (Mn) = 1. This is shown by the presence of two maxima on the manganese concentration profile in the dendritic cell. It was calculated that the copper partition coefficient in these alloys should also pass through the value k (Cu) = 1; however, this has not been confirmed experimentally. The possible reason for this may be because of the inaccuracies in the phase diagram of the Cu-Ni-Mn system that was used and also in the difference of the copper and manganese diffusion coefficients in the alloy.
10.1007-s11661-015-2745-3	-1		In this work, we study the microstructures upon rapid solidification from the melt which occurs in Cu-Cr electrical contacts after switching operations. As the local cooling rates are difficult to be determined experimentally, we numerically compute the mean radius of Cr-particles from phase separation as a function of the cooling rate by utilizing a convective Cahn-Hilliard model. Based on the computationally derived correlation and on the metallographically observed microstructure, we are able to extract back the local cooling rates during heat treatment. We further examine the effect of Marangoni convection on the phase separation structure in a particularly composed simulation study. We obtain the cooling rate for a given particle size affected by the solutal Marangoni convection. (C) The Minerals, Metals & Materials Society and ASM International 2015
10.1007-s11661-015-2870-z	-1		The effect of addition of 0.04 or 0.2 mass pct Ti on the mechanical properties of a Cu-2.0 mass pct Ni-0.5 mass pct Si alloy has been investigated. The addition of 0.04 mass pct Ti enhances the strength of the Cu-Ni-Si alloy without reducing its electrical conductivity. This increase in strength is caused by the decrease in inter-precipitate spacing of delta-Ni2Si precipitates. The addition of trace Ti reduces the equilibrium concentration of Ni and Si atoms in the alloy bearing the delta precipitates, resulting in an increase in the volume fraction of delta precipitates and decrease in the inter-precipitate spacing. However, the addition of 0.2 mass pct Ti to the Cu-Ni-Si alloy decreases the strength of the alloy. The reduction in strength is attributed to the decrease in the volume fraction of delta precipitates caused by the reduction in Ni and Si atoms in the Cu matrix resulting from the formation of Ni16Si7Ti6 particles.
10.1007-s11661-015-2921-5	-1		The kinetics and phase selection mechanisms involved in the crystallization of an amorphous Cu-Zr alloy of eutectic composition (Cu56Zr44) were investigated using in situ high-energy X-ray diffraction (HEXRD), transmission electron microscopy (TEM), and differential scanning calorimetry (DSC) under isothermal and constant heating rate conditions. In situ HEXRD results for 10 K/min (10 A degrees C/min) heating indicate that the amorphous alloy devitrifies into CuZr2 and mainly Cu10Zr7 at the crystallization temperature of 725 K (452 A degrees C). The sequence continues with the precipitation of CuZr (B2) at 1004 K (731 A degrees C), where these three phases coexist until the decomposition of CuZr2 is observed at 1030 K (757 A degrees C). The two equilibrium phases Cu10Zr7 and CuZr (B2) remain present on further heating until melting at the eutectic temperature for the Cu56Zr44 alloy. TEM investigation of the isothermal [705 K (432 A degrees C)] crystallization sequence reveals primary nucleation and growth of the Cu10Zr7 phase, where growth of the Cu10Zr7 crystals is initially planar with a transition to a cellular morphology, associated with partitioning of Zr at the growth front. Related cellular structures and composition profiles are quantified. (C) The Minerals, Metals & Materials Society and ASM International 2015
10.1007-s11661-015-3150-7	8	hot; deformation; strain; strain rate; dynamic; hot deformation; recrystallization; dynamic recrystallization; flow; rate; flow stress; compression; constitutive; degrees; stress	Hot deformation behavior of the Cu-2Ni-0.5Si-0.15Ag alloy was investigated by hot compression tests using the Gleeble-1500D thermo-simulator in the 873 K to 1073 K (600 degrees C to 800 degrees C) temperatures range with the 0.01 to 5 s(-1) strain rate. The flow stress strongly depends on the deformation parameters, including temperature and strain rate. The flow stress decreases with the deformation temperature and increases with the strain rate. The constitutive relationship between the peak stress, the strain rate, and the deformation temperature can be described by the Zener-Hollomon Z parameter in the hyperbolic sine function with the hot deformation activation energy of 316 kJ/mol. The dynamic recrystallization (DRX) is one of the important softening mechanisms of the Cu-2Ni-0.5Si-0.15Ag alloy during hot deformation. The DRX behavior of the Cu-2Ni-0.5Si-0.15Ag alloy is strongly affected by the Z parameter. Lower Z parameter leads to more adequate DRX proceeding. (C) The Minerals, Metals & Materials Society and ASM International 2015
10.1007-s11661-015-3238-0	16	wear; composite; composites; powders; milling; particles; powder; wt; sliding; friction; hardness; matrix; mechanical; surface; properties	Cu/Al2O3 composite coatings were prepared from acidic copper sulfate bath containing ultrafine Al2O3 particles by direct current plating method to increase the surface-mechanical property of Cu for its possible use as electrical contact. Effect of ultrafine Al2O3 particle concentration in electrolyte and deposition current density on the surface-mechanical properties of the coatings was investigated. Coatings were characterized by scanning electron microscopy and X-ray diffraction (XRD) techniques for the purpose of surface morphology and phase study. From XRD data, crystallographic texture of the coating was also analyzed. To study the mechanical properties, microhardness testing, adhesion, and wear test were carried out. Improved hardness of the resultant coatings was observed and was correlated with the wt pct of ultrafine particle in the Cu matrix, matrix structure, and crystallographic orientation. Better wear property of the composite coating was also reported from the wear plot and wear track morphology. Altogether, better coating property was attributed toward finer matrix, hard reinforced phase, and preferred orientation in selected conditions. Electrical conductivity of the coating was affected by grain size and second-phase concentration, and the values obtained were in the usable range required for electrical applications.
10.1007-s11661-016-3353-6	-1		For predicting solidification cracking by thermal stress analysis, the mechanical properties in the partially solidified state based on the experimental results are the best hope. However, the Young's modulus has never been investigated for copper alloys. In this study, stress-strain curves of a Cu-Zn alloy in the partially solidified state for various solid fractions were obtained using a specially developed horizontal tensile test device. Furthermore, by removing the load during the tensile test, the spring-back (elastic behavior) was observed and the Young's modulus was obtained.
10.1007-s11661-016-3477-8	-1		Copper has been in use for at least 10,000 years. Copper alloys, such as bronze and brass, have played important roles in advancing civilization in human history. Bronze artifacts date at least 6500 years. On the other hand, discovery of intriguing properties and new applications in contemporary technology for copper and its compounds, particularly on nanoscale, have continued. In this paper, examples for the applications of Cu and Cu alloys for advanced device applications will be given on Cu metallization in microelectronics devices, Cu nanobats as field emitters, Cu2S nanowire array as high-rate capability and high-capacity cathodes for lithium-ion batteries, Cu-Te nanostructures for field-effect transistor, Cu3Si nanowires as high-performance field emitters and efficient anti-reflective layers, single-crystal Cu(In,Ga)Se-2 nanotip arrays for high-efficiency solar cell, multilevel Cu2S resistive memory, superlattice Cu2S-Ag2S heterojunction diodes, and facet-dependent Cu2O diode.
10.1007-s11661-016-3628-y	-1		The influence of the addition of Sn to Cu-Al-Ni alloy as a fourth element with different percentages of 0.5, 1.0, and 1.5 wt pct on the microstructure, phase-transformation temperatures, mechanical properties, and corrosion behaviors was investigated. The modified and unmodified alloys were fabricated by mechanical alloying followed by microwave sintering. The sintered and homogenized alloys of Cu-Al-Ni-xSn shape-memory alloys had a refined particle structure with an average particle size of 40 to 50 A mu m associated with an improvement in the mechanical properties and corrosion resistance. With the addition of Sn, the porosity density tends to decrease, which can also lead to improvements in the properties of the modified alloys. The minimum porosity percentage was observed in the Cu-Al-Ni-1.0 wt pct Sn alloy, which resulted in enhancing the ductility, strain recovery, and corrosion resistance. Further increasing the Sn addition to 1.5 wt pct, the strength of the alloy increased because the highest volume fraction of precipitates was formed. Regarding the corrosion behavior, addition of Sn up to 1 wt pct increased the corrosion resistance of the base SMA from 2.97 to 19.20 k Omega cm(2) because of formation of a protective film that contains hydrated tin oxyhydroxide, aluminum dihydroxychloride, and copper chloride on the alloy. However, further addition of Sn reduced the corrosion resistance.
10.1007-s11661-016-3671-8	-1		This study reports the current status of grain refinement of copper accompanied in particular by a critical appraisal of grain refinement of phosphorus-deoxidized, high residual P (DHP) copper microalloyed with 150 ppm Ag. Some deviations exist in terms of the growth restriction factor (Q) framework, on the basis of empirical evidence reported in the literature for grain size measurements of copper with individual additions of 0.05, 0.1, and 0.5 wt pct of Mo, In, Sn, Bi, Sb, Pb, and Se, cast under a protective atmosphere of pure Ar and water quenching. The columnar-to-equiaxed transition (CET) has been observed in copper, with an individual addition of 0.4B and with combined additions of 0.4Zr-0.04P and 0.4Zr-0.04P-0.015Ag and, in a previous study, with combined additions of 0.1Ag-0.069P (in wt pct). CETs in these B- and Zr-treated casts have been ascribed to changes in the morphology and chemistry of particles, concurrently in association with free solute type and availability. No further grain-refining action was observed due to microalloying additions of B, Mg, Ca, Zr, Ti, Mn, In, Fe, and Zn (similar to 0.1 wt pct) with respect to DHP-Cu microalloyed with Ag, and therefore are no longer relevant for the casting conditions studied. The critical microalloying element for grain size control in deoxidized copper and in particular DHP-Cu is Ag.
10.1007-s11661-016-3715-0	2	corrosion; surface; film; electrochemical; films; spectroscopy; layer; current; solution; potential; resistance; composition; x-ray; ions; showed	In this article, electrochemical deposition of the nanocrystalline Cu1-x Zn (x) alloys on to aluminum substrates from a non-cyanide citrate electrolyte at 52.5, 105, 157.5, and 210 A m(-2) current densities were described. The bath solution of the Cu1-x Zn (x) alloys consisted of 0.08 mol L-1 CuSO4 center dot 5H(2)O, 0.2 mol L-1 ZnSO4 center dot 7H(2)O, and 0.5 mol L-1 Na3C6H5O7. The effect of the current density on the microstrain, grainsize, phase structure, and DC electrical resistivity behavior was investigated. The electrolyte was investigated electrochemically by cyclic voltammetry (CV) studies. A scanning electron microscope (SEM) was used to study the morphologies of the deposits. Deposited alloys were investigated by energy-dispersive X-ray spectroscopy (EDX), X-ray diffraction (XRD), and four-point probe electrical resistivity techniques. With an increase in applied current density values from 52.5 to 210 A m(-2), the amount of deposited copper in the alloy was decreased significantly from 65.5 to 16.6 pct and zinc increased from 34.4 to 83.4 pct. An increase in the current density was accompanied by an increase in grain size values from 65 to 95 nm. SEM observations indicated that the morphology of the film surface was modified to bigger grained nanostructures by increasing the current density. The XRD analysis showed alloys have a body-centered cubic (bcc) crystal structure with preferential planes of (110) and (211). Furthermore, four-point measurements of the films revealed that the resistivity of the deposited films was tailored by varying current densities in the electrolyte.
10.1007-s11661-016-3891-y	6	grain; deformation; strain; strength; dislocation; cu-; tensile; size; ecap; grain size; sfe; ductility; hardening; high; stress	To explore the effect of cyclic pre-deformation on static mechanical behavior of materials with different stacking fault energies (SFEs), polycrystalline Cu-16 at. pct Al alloy with a low SFE is selected as the target material in the present work, and the strengthening micro-mechanisms induced by cyclic pre-deformation are compared with the previous studies on pure Al with a high SFE and Cu with an intermediate SFE. The results show that the movement of dislocations exhibits a high slip planarity during cyclic pre-deformation at different total strain amplitudes Delta epsilon (t)/2, and some nano-sized deformation twins are formed after subsequent tension. The cyclic pre-deformation at an appropriate Delta epsilon (t)/2 of 1.0 x 10(-3) promotes a significant increase in ultimate tensile strength sigma (UTS) nearly without loss of tensile ductility, which primarily stems from the introduction of many mobile planar slip dislocations by cyclic pre-deformation as well as the formation of nano-sized deformation twins during subsequent tension. Based on the comparison of the strengthening micro-mechanisms induced by cyclic pre-deformation in Al, Cu, and Cu-16 at. pct Al alloy, it is deduced that a low-cycle cyclic pre-deformation at an appropriate condition is expected to cause a better strengthening effect on the static tensile properties of low SFE metals.
10.1007-s11661-017-4000-6	-1		Different compositions of Cu-Ni/Al2O3 nanocomposites were prepared by a chemical-based synthesis of co-formed oxides (CuO-NiO-Al2O3) nanoparticles followed by selective hydrogen reduction of the Cu and Ni oxides and finally by consolidation into pellets. The synthesized composites with both phases (metallic and oxide) containing nanoparticles in the 5 to 60 nm range have been systematically produced. Micro- and nanoscale characterization techniques were extensively employed in all stages of the process. X-ray diffraction (XRD) and transmission electron microscopy (TEM) analyses have shown a heterogeneous distribution of chemical elements resulting in the formation of Cu- and Ni-rich nanoparticles containing Al2O3 phase in a controlled low volume fraction, which later mostly dispersed between the metallic particle and, to a lesser extent, within metallic particles. After consolidation, under uniaxial pressure followed by sintering, the compacted nanocomposite observed in the transmission electron microscope (TEM) revealed that the Al2O3 have been more homogeneously distributed as such: the majority of it at the newly formed grain boundaries of the consolidated pellet and a small part of it within the metallic Cu-Ni matrix. Microhardness measurements demonstrate that dispersion of Al2O3 was successfully achieved as reinforcement phase, yielding up to 100 pct increase in hardness.
10.1007-s11661-017-4008-y	-1		It is well known that the growth and motion of equiaxed crystals govern important microstructural features, especially in larger castings such as heavy ingots. To determine the origin of the equiaxed crystals, heterogeneous nucleation, and/or fragmentation of dendrite arms from columnar regions are often discussed. In the present study, we demonstrate that under certain conditions relatively large areas of mushy regions slide downward and form spectacular crystal avalanches. These avalanches crumble into thousands of dendritic fragments, whereby the larger fragments immediately sediment and the smaller proceed to behave as equiaxed crystals. Traces of such crystal avalanches can be seen by conspicuous equiaxed layers in the lower part of the casting. From the arguments in the discussion, it is believed that such a phenomenon may occur in alloys which reveal an upward solutal buoyancy in the interdendritic mush . This would include certain steels and other alloys such as Cu-Al, Pb-Sn, or Ni-Al-alloys. Moreover, the occurrence of crystal avalanches contribute to the formation of V-segregations. (C) The Author(s) 2017. This article is published with open access at Springerlink.com
10.1007-s11661-017-4072-3	17	wear; composites; coating; friction; composite; coatings; surface; tribological; properties; wear resistance; resistance; powder; sliding; matrix; wear rate	The Cu-Ni-Mn alloy-based hardfacing coatings reinforced by WC particles (WC/Cu-Ni-Mn) were deposited on a steel substrate by a manual oxy-acetylene weld hardfacing method. A sound interfacial junction was formed between the WC particles and the Cu-Ni-Mn alloy metal matrix binder even after the age-hardening treatment. The friction and wear behavior of the hardfacing coatings was investigated. With the introduction of WC particles, the sliding wear resistance of the WC/Cu-Ni-Mn hardfacing coatings was sharply improved: more than 200 times better than that of the age-hardening-treated Cu-Ni-Mn alloy coating. The sliding wear resistances of the as-deposited and the age-hardening-treated WC/Cu-Ni-Mn hardfacing coatings were 1.83 and 2.26 times higher than that of the commercial Fe-Cr-C hardfacing coating, which is mainly ascribed to the higher volume fraction of carbide reinforcement. Owing to the precipitation of the NiMn secondary phase in the Cu-Ni-Mn metal matrix, the age-hardening-treated coating had better wear resistance than that of the as-deposited coating. The main sliding wear mechanisms of the age-hardening-treated coatings are adhesion and abrasion. (C) The Minerals, Metals & Materials Society and ASM International 2017
10.1007-s11661-017-4125-7	13	clusters; atomic; glass; atoms; composition; dynamics; metallic; icosahedral; glasses; simulations; molecular; cu-zr; molecular dynamics; metallic glasses; structural	The intrinsic thermodynamic links that exist between thermochemical and thermophysical quantities, especially their temperature, pressure, and composition dependence, have seldom been analyzed in sufficient detail in literature. In this connection, an attempt is made to establish a thermodynamic bridge, relating Delta(o) H (mix), the standard enthalpy of mixing with Delta(o) B (T) , the change in isothermal bulk modulus as a result of alloying and its composition and temperature dependence. In essence, by adopting the standard regular and subregular solution approximations to the composition dependence of mixing enthalpy; and furthermore, incorporating separately the configurational (Delta(o) S (conf)) and vibrational (Delta(o) S (Vib)) entropy contributions to mixing Gibbs energy change (Delta(o) G (mix)), simple models have been derived for the composition and temperature variations of excess bulk modulus Delta B (T) . In particular, a regular or subregular solution analog of the composition variation of Delta B (T) is shown to be possible if Delta(o) H (mix) could be described likewise. The vibrational entropy contribution to Delta B (T) is found to be important only when the change in Gruneisen parameter during alloying turns to be significant. The practical utility of the theoretical framework developed in this study has been demonstrated by applying it to disordered fcc Cu1-x Ni (x) alloys, wherein it is shown that Delta(o) H (mix) and Delta(o) B (T) are linearly correlated, as predicted by the theory.
10.1007-s11661-017-4176-9	6	grain; deformation; strain; strength; dislocation; cu-; tensile; size; ecap; grain size; sfe; ductility; hardening; high; stress	Using surface mechanical attrition treatment (SMAT), a gradient structure composed of two gradient structure (GS) layers and a coarse grain (CG) layer was generated from a Cu-5.7 wt pct Ge alloy, significantly improving the yield strength of the sample. Unloading-reloading tests showed an unusual Bauschinger effect in these GS samples. The back stresses caused by the accumulated geometrically necessary dislocations (GNDs) on the GS/CG border increased with increasing strain. As found by electron backscatter diffraction (EBSD), the GNDs are mainly distributed in the gradient structured layer, and the density of the GNDs increase with increasing SMAT time. The effect of the back stress increased with increasing SMAT processing time due to the increase in the strain gradient. The pronounced Bauschinger effect in a GS sample can improve the resistance to forward plastic flow and finally contributes to the high strength of GS samples.
10.1007-s11661-017-4292-6	15	aging; strength; conductivity; electrical conductivity; electrical; mpa; treatment; strengthening; degrees; cu-; cold; precipitation; tensile strength; tensile; iacs	The effects of different aging processes on electrical conductivity and microhardness of a Cu-1.0Zr alloy were investigated. Microstructure and precipitates of the aged alloy were analyzed by transmission electron microscopy, and the aging strengthening mechanism of the Cu-1.0Zr alloy is discussed. Good comprehensive performance of the Cu-1.0Zr alloy can be obtained by aging at 773K (500 degrees C) for 1 hour, for which electrical conductivity reached 80.2 pct IACS, while microhardness reached 155.6 HV. Small amounts of a Zr-rich phase and annealing twins were present in the solid solution. A large amount of 3-18 nm Cu10Zr7 precipitates were present in the copper matrix. At the early stage of aging, the precipitates were small and their density was relatively low. As aging time progressed, the precipitates gradually increased in size. After overaging, the precipitated phase was dissolved, resulting in reduced microhardness. After aging at 723 K (450 degrees C) for 6 hours, the precipitates were Cu10Zr7. The peak Cu-1.0Zr alloy performance was achieved after aging at 773 K (500 degrees C) for 1 hour, and the main reason for the performance increase is coherent strain hardening. (C) The Minerals, Metals & Materials Society and ASM International 2017
10.1007-s11661-017-4338-9	-1		Upward continuous casting was used to manufacture Cu-Cr-Ag high-strength high-conductivity alloys, for comparison with conventional processing methods. The behavior of the alloy samples was measured, including tensile strength, microhardness, and electrical conductivity. The microstructure was characterized using optical microscopy and transmission electron microscopy after each processing step. It was found that microstructure with columnar grains due to upward continuous casting made it possible to enhance strength whilst maintaining the ductility of the alloys during the aging process. The combined drawing-aging process has the potential to be used numerous times during the manufacture of Cu-Cr-based high-strength high-conductivity alloys. (C) The Minerals, Metals & Materials Society and ASM International 2017
10.1007-s11661-017-4363-8	6	grain; deformation; strain; strength; dislocation; cu-; tensile; size; ecap; grain size; sfe; ductility; hardening; high; stress	Precipitation hardening copper alloy C70250 was selectively laser melted to successfully produce components around 98 pct dense with high mechanical strength and electrical conductivity. Aging heat treatments were carried out at 723 K (450 degrees C) directly on as-printed samples up to 128 hours. Mechanical testing found that peak yield strength of around 590 MPa could be attained with an electrical conductivity of 34.2 pct IACS after 8 hours of aging. Conductivity continues to increase with further aging while the peak strength appears to be less sensitive to aging time exhibiting a broad range of time where near-peak properties exist. After aging for 128 hours, there is a drop in yield strength to 546 MPa with an increase in conductivity to 43.2 pct IACS. Electron microscopy analysis revealed nanometer-scale silicon-rich oxide particles throughout the material that persist during aging. Deformation twinning is observed in the peak-age condition after tensile testing and several strengthening mechanisms appear to be active to varying degrees throughout aging which account for the broad range of aging time where nearly the peak mechanical properties exist. (C) The Minerals, Metals & Materials Society and ASM International 2017
10.1007-s11661-018-4800-3	-1		Cu-Pd-Ag alloy wires with a relatively low Ag content are used widely in electronics. This alloy is usually subjected to age hardening to increase its strength . However, the alloy microstructure that results when the alloy is processed as a wire has not been clarified sufficiently to elucidate the hardening mechanism. A clarification of the microstructure is critical to control the mechanical properties of the alloy wire. In this study, we investigated the detailed microstructure variation of the alloy wire after heat treatment. Microscopy showed that the alloy wire contained many parallel rods with an Ag-rich alpha phase that extended along the axial direction of a Cu-rich alpha-phase matrix before heat treatment. After heat treatment at 623 K for 1 hour, the morphology of the rods in the matrix remained mostly unchanged. Detailed observations revealed that the matrix was transformed to a nanolamellar structure with beta and alpha(2) phases. Many beta' phases with a thickness of a few atomic layers precipitated in the rods. Both nanostructures investigated in this study were expected to contribute to wire hardening through a short-fiber strengthening mechanism. (C) The Minerals, Metals & Materials Society and ASM International 2018
10.1007-s11661-018-4816-8	-1		We designed an optimal procedure to prepare Cu-Ti alloy wires with an excellent combination of strength and electrical conductivity, by drawing conventional peak-aged alloys as well as over-aged ones. When drawing the peak-aged alloy, which exhibited the maximum hardness after aging and a low electrical conductivity, the strength of the wires increased rapidly in the initial stage of drawing but then saturated on further drawing. On the contrary, when drawing the over-aged alloy of inferior hardness but superior electrical conductivity, the strength increased steadily through drawing and eventually exceeded the value of the wires drawn from the peak-aged alloy. Also, the electrical conductivity of the wires drawn from the over-aged alloy was always much greater than that from the peak-aged alloy. Thus, we demonstrated that the procedure of over-aging and then drawing severely is able to enhance both the strength and the electrical conductivity for the Cu-Ti alloys, rather than the conventional peak-aging and drawing process. Noted that the performance of the wires drawn from the over-aged alloy is comparable with that of commercial Cu-Be wires, which are considered to possess the combination of greatest strength and conductivity in Cu-based alloys. (C) The Minerals, Metals & Materials Society and ASM International 2018
10.1007-s11661-018-4921-8	-1		The influences of rigid heterointerfaces on the dynamic recrystallization (DRX) process and texture evolution during hot rolling of a graphene nanoribbon (GNR)-reinforced Cu-matrix composite system are investigated. The Cu/GNR interfaces contribute to the atypical recrystallization-type and brass-type textures developed in composites within 0.5 and 3vol pct GNRs, respectively, deviating from the normal Cu-type texture found in their pure Cu counterpart. The heterointerfaces may change the texture evolution of the Cu matrix in four ways, namely, retard the dislocation cross slip, activate partial slip, generate geometrically necessary dislocations, and promote the DRX process. These are corroborated through viscoplastic self-consistent simulations, which well reproduce the texture development in all samples by considering the interface-dislocation interactions, the activation of non-normal slip, and the interface-driven DRX nucleation. This study suggests the possibility of manipulating the microstructure, texture, and mechanical properties of traditional metallic materials through the design of heterophase interfaces.
10.1007-s11661-018-4980-x	-1		Inadequate room-temperature plasticity limits the application of bulk metallic glasses (BMGs). This study focuses on enhancing the plasticity of BMGs for widening their applications. Composition modification of Cu60Zr25Ti15 through the minor addition of Ni is the approach adopted in this study. A systematic increase in mechanical properties is observed with increasing Ni content (up to 5 at. pct), followed by a decrease thereafter. Values of yield stress (2425 MPa), fracture stress (2513 MPa), maximum stress (2725 MPa), and plastic strain (16 pct) exhibited by (Cu60Zr25Ti15)(95)Ni-5 BMGs are higher than those reported in the literature for Cu-BMGs (high Cu content). Analysis of the glass transition region indicated that the enthalpy values of the exothermic heat flow prior to glass transition (H-bg) and the fragility parameter (m) are well correlated with the plasticity of the alloys. The increasing fragility parameter and exothermic enthalpy correspond to higher free volume. Therefore, high plasticity values can be attributed to the free volume modification (creation and distribution) caused by Ni addition. This free volume modification initiates shear bands and promotes their branching; consequent interactions among them increase the resistance to shear band propagation and, thereby, delay the fracture.
10.1007-s11661-019-05126-y	17	wear; composites; coating; friction; composite; coatings; surface; tribological; properties; wear resistance; resistance; powder; sliding; matrix; wear rate	Cu-Ni-Mn alloy coatings and their associated composite coatings reinforced with tungsten-carbide (WC) particles were deposited onto a steel substrate using the manual oxy-acetylene weld hardfacing method. The sliding wear behaviors in air at 350 degrees C were investigated. The relative wear-resistance values of the as-deposited and the age-hardened WC/Cu-Ni-Mn hardfacing coatings with regard to the commercial Fe-Cr-C hardfacing coatings at 350 degrees C were 1.90 and 2.39, respectively. The excellent sliding wear-resistance performance of the WC/Cu-Ni-Mn hardfacing coatings was mainly ascribed to the hard and thermally stable WC particles embedded uniformly in the Cu-Ni-Mn metal matrix. The high-temperature wear mechanisms of the coatings were determined to be mainly abrasion and adhesion. The oxidation of the metal matrix improved sliding wear-resistance performance at high temperatures. Compared to the results at room temperature, the friction coefficients of the coating decreased, whereas the sliding wear volume loss increased slightly under dry sliding wear conditions at high temperatures.
10.1007-s11661-019-05206-z	-1		Cu-Bi alloy with high Bi content can be used for thermal surge protection and energy storage. For these applications, creep at high temperatures, including temperatures above the melting temperature of Bi, T-m,T-Bi, becomes important. Accordingly, the creep behavior of Cu-Bi alloys, comprising 30 and 40 vol pct Bi, was studied under compression at temperatures above and below T-m,T-Bi. At 200 degrees C, which is below T-m,T-Bi, Cu-Bi showed a stress exponent of similar to 4 at high stresses and similar to 1 at low stresses. Finite element analysis revealed that the creep behavior of Cu-Bi at 200 degrees C was predominantly governed by Bi. On the other hand, at temperatures higher than T-m,T-Bi, Cu-Bi showed a short transient stage at high stresses, followed by sudden failure of the material. However, at low stresses, the sample first continued to expand and then started to accumulate compressive strain. A qualitative model based on interaction between liquid Bi and Cu is developed to explain the observed creep behavior at temperatures higher than T-m,T-Bi. The results obtained here shed light on the creep behavior of alloys with constituents having significantly different creep behavior and containing a non-reacting liquid phase. (C) The Minerals, Metals & Materials Society and ASM International 2019
10.1007-s11661-019-05243-8	-1		Although dilute Cu-Cr alloys are frequently used for applications involving sliding contacts, their wear mechanism at elevated temperatures has rarely been explored. We fabricated a bulk Cu-6 wt pct Cr alloy using high-energy ball milling and spark plasma sintering, and systematically investigated its dry sliding wear behavior against 440C stainless steel at room temperature and 300 degrees C. The alloy had a heterogeneous microstructure consisting of coarse-grained Cu (average grain size: 1.5 mu m) distributed into a nanocrystalline Cu-Cr matrix (average Cu grain size: 77 nm; Cr-rich precipitate size: 18 nm), which gave high strength and plasticity (ultimate compressive strength: 1020 MPa; strain-to-failure: 26.0 pct) at room temperature. At 300 degrees C, the strength was significantly reduced, the coefficient of friction and wear rate increased, and the dominant wear mode switched from adhesive wear to oxidative/abrasive wear. Uniformly distributed nanoscale Cr-rich and Cr oxide precipitates hindered severe plastic deformation near the sliding surface during wear at room temperature; at 300 degrees C, severe plastic deformation was observed, with elongated Cu grains and uniformly dispersed Cr-rich and Cr oxide nanoparticles. Formation of a discontinuous glaze layer consisting of equiaxed nanograins of Cu, Cu oxides, and Cr oxides resulted in severe abrasion-assisted wear, and reduced the wear resistance at 300 degrees C.
10.1007-s11661-019-05255-4	-1		In this study, the microstructure, hardness, and wear resistance of two kinds of copper alloy are demonstrated to be affected by both composition, annealing temperature, and phases present with a sliding block-on-ring test, where the ring is 316 stainless steel. With a higher content of Zn, the solubility of Mn and Si would decrease, resulting in increased volume fraction of the hard omega-Mn5Si3 phase (with a high nanoindentation hardness of 12.9 GPa). Moreover, the higher contents of Mn and Si lead to the formation of large primary polyhedron P omega-Mn5Si3 cylinders during solidification. With the help of two-stage forging, the primary polyhedron P omega-Mn5Si3 grow along [0001], enabling the large primary Mn5Si3 cylinders all parallel to each other. This special microstructure could significantly improve the wear resistance in comparison with the samples with a microstructure containing only small and randomly oriented precipitates. Such parallel primary polyhedron P omega-Mn5Si3 cylinders can act as reinforcements to grab the matrix, effectively improving the wear resistance.
10.1007-s11661-019-05360-4	-1		Grain boundary structure and chemical composition have been shown to play important roles in plasticity, strength, creep, diffusivity, and conductivity of fine-grained metallic materials. Wetting of grain boundaries in metallic materials with nanoscale intergranular intermetallic compound films (NIICFs) is suggested to offer enhanced strength and ductility of alloys. In the current study, the NIICF wetting Cu-Zr micrograins of the matrix is observed in a Cu-5 at. pct Zr alloy produced by powder metallurgy. The underlying mechanism responsible for the formation of these NIICFs is discussed, and the effect of these films on the strength and strain-hardening capacity of the alloy is evaluated.
10.1007-s11661-019-05366-y	-1		Incremental sheet forming (ISF) is an emerging cold forming process with a high economic payoff. In this study, the influence of the ISF process on the tensile properties of Cu-clad Steel sheet is analyzed experimentally. Depending on the forming conditions, the post-ISF values of yield strength, tensile strength, and ductility are found to range from 161 to 430, 288 to 449 MPa, and 4.93 to 16.62 pct, respectively. These properties show a strong dependence on several correlated quantities such as the applied plastic strain, grain size, and mean residual stress. As the plastic strain increases from 0.08 to 0.8, the width of the grain decreases from 8.11 to 5.78 mu m and the residual stress increases from-15 to-131 MPa. In comparison to the unformed sheet, ISF enhances the yield strength (4.6 to 117 pct) and tensile strength (0.6 to 73 pct). The nature of change in ductility (- 67 to 117 pct), however, depends on the process conditions, especially the state of the unformed sheet (i.e., rolled/annealed) and the value of applied strain. In general, the rolled (or prestrained) sheet upon ISF experiences an increase in ductility. The annealed sheet, however, sees a drop in ductility when the forming strains are low (e.g., < 0.4) and an increase in ductility when the strains are high (e.g., > 0.4). X-ray diffraction (XRD) and electron dispersive spectroscopy (EDS) analyses confirm that no new phase formed during ISF.
10.1007-s11661-019-05483-8	-1		High-performance, ultra-low Cu layer thickness ratio pure Cu/8011 Al alloy/1060 Al alloy (Cu/8011/1060, for short) clads were first fabricated by roll casting and then roll bonding. The effects of rolling reduction rates on the microstructural evolutions and mechanical properties of Cu/8011/1060 clads during the roll-bonding process have been systematically investigated. Results show that the continuous but unequal-thickness intermetallic compound (IMC) layer is fractured after roll bonding. The fracture location is mainly at the transition zone between type I and type II IMCs or in the interiors of type I and type II IMCs. The IMCs are identified as Al4Cu9, AlCu and Al2Cu. The Cu layer thickness ratio decreases from 13.7 to 4.1 pct after roll bonding. The Cu/8011/1060 clads prepared at the rolling reduction rate of 47 pct have the best comprehensive mechanical performance with an ultimate tensile strength (UTS) of 135.7 MPa and elongation (EL) of 25.5 pct. Two different tensile fracture modes are observed for Cu/8011/1060 clads fabricated at different rolling reduction rates.
10.1007-s11661-019-05545-x	16	wear; composite; composites; powders; milling; particles; powder; wt; sliding; friction; hardness; matrix; mechanical; surface; properties	The present work investigates the microstructure development and mechanical properties of mechanically alloyed and hot-pressed copper (Cu)-X wt pct aluminum (Al) (X = 0, 3, 5, 10, 15) alloys. The morphology of the ball-milled Cu-Al powders changed from coarse flaky structure to small hard agglomerates with the addition of Al. It was observed that the density of Cu-Al samples varied between ~ 95 and 98 pct of theoretical density (rho(th)) after hot pressing (Temperature: 500 degrees C, Pressure: 500 MPa, Time: 30 min). The crystallite size of Cu-Al samples decreased for both the milled powders and hot-pressed samples. The XRD and SEM-EDS analyses of the hot-pressed samples confirmed the presence of alpha-Cu solid solution phases for the Cu alloyed with Al up to 5 wt pct. On the other hand, further addition of Al to Cu leads to the formation of both intermetallic compound (Cu9Al4) and solid solution phase. The nano-indentation tests indicated a significant increase in hardness (2.4 to 7.9 GPa) and elastic modulus (121.1 to 177.4 GPa) of Cu-Al alloys. The Cu-Al alloys were measured with very high compressive strength (813.8 to 1120.2 MPa) and the compressive strain varied in the range of 29.81 to 5.81 pct.
10.1007-s11661-020-05668-6	-1		Cu9Ni6Sn alloys were prepared by conventional casting (CC) and twin-roll casting (TRC). The CC-processed specimens possessed dendritic structures, and Sn was distributed mainly in the inter-dendritic region and formed dendritic segregation. The TRC-processed specimens were composed of equiaxed grains and a heterogeneous structure. The distribution of Sn showed gradient characteristics, with more Sn in the surface layer and less Sn in the center. The TRC-processed specimens had more inhomogeneous mechanical properties than the CC-processed specimens.
10.1007-s11661-020-05801-5	-1		Age-hardened Cu-Ti alloys are widely used as conductive materials in small electrical devices, so it is important for them to have suitable mechanical and electrical properties. One of the principal guidelines for improving the mechanical properties of Cu-Ti alloys is to suppress the formation of coarse discontinuous precipitates within them. Herein, we investigated the microstructure and properties of a Cu-4 at. pct Ti alloy aged under hydrogen pressures of 0 to 0.6 MPa, focusing on discontinuous precipitation at the grain boundaries. During the early stages of aging, fine needle-shaped metastable beta '-Cu4Ti precipitates formed continuously in the matrix. With further aging, these beta '-Cu4Ti precipitates continued to nucleate and grow, and simultaneously cellular components composing of the lamellae of Cu solid solution and the stable beta-Cu4Ti discontinuous precipitates were formed at grain boundaries. Nevertheless, the formation of these cellular components was significantly suppressed when aging under hydrogen pressures of above 0.03 MPa. Upon aging under higher hydrogen pressures (> 0.10 MPa), some granular TiH2 precipitates formed, and the preformed beta '-Cu4Ti precipitates decomposed. Upon aging under 0.03 MPa hydrogen pressure, fine metastable beta '-Cu4Ti precipitates were formed dominantly, because the formation of stable beta-Cu4Ti laminates was suppressed and the TiH2 precipitates was still not formed. Hence, the hardness was maintained under over-aging conditions.
10.1007-s11661-020-05873-3	-1		It is well known that a balance between the generation of low-angle and high-angle grain boundaries (LABG and HAGB) is achieved in materials undergoing a severe plastic deformation (SPD) process. It is also observed that most annealed materials evolve from a substantial fraction of LAGB at the early deformation steps towards a steady state in which an equilibrium between LAGB and HAGB fractions is attained. In the present work, such a balance is analyzed for different alloys,i.e.,Cu, Al, and Fe based. A mathematical expression is proposed for the amount of LAGB and HAGB as a function of the strain impaired which in turn can be used to predict the number of passes (especially for ECAP) or the amount of total deformation for any SPD process necessary to attain a steady microstructure. The model seeks to serve as a first approximation of the mechanical and microstructural properties of ultrafine grain metal materials.
10.1007-s11661-020-05892-0	6	grain; deformation; strain; strength; dislocation; cu-; tensile; size; ecap; grain size; sfe; ductility; hardening; high; stress	The Cu-Cr-Zr-Ti alloy was subjected to single-hit plane strain compression tests in the temperature range of 923 K to 1073 K (650 degrees C to 800 degrees C) and at two different strain rates of 0.1 and 1 s(-1). These tests were performed to ascertain the kinetics of microstructural evolution resulting by dynamic recrystallization (DRX) in the alloy under hot deformation conditions. The differences in the extent of DRX under various deformation conditions were established by plotting fractional softening as a function of strain and time. Further, the Avrami exponent was found to decrease with increase in deformation temperature. This was attributed to early onset of recrystallization leading to subsequent work hardening of the recrystallized grains and grain growth at higher temperatures which results in the loss of nucleation sites due to reduced grain boundary area. Microstructural observations made using optical microscopy, scanning electron microscopy (SEM), and electron backscattered diffraction (EBSD) revealed nucleation to occur in the following steps: elongation of grains perpendicular to the compression direction, bulging of elongated grain boundaries due to strain-induced boundary migration (SIBM), and subsequent subgrain formation behind the bulged boundary due to strain-induced low-angle boundaries. Finally, the equation describing the DRX kinetics under plane strain conditions for the alloy was established as X = 1-exp [-0.455 x ((epsilon-epsilon(c))/epsilon(p))(2.84)].
10.1007-s11661-020-06051-1	-1		As candidates for conductors used in high-field extreme conditions, Cu-Agin-situcomposites are required to possess high strength and conductivity; however, most Cu-Agin-situcomposites do not possess both characteristics. Therefore, it is important to determine the appropriate composition design of Cu-Ag composites that can enhance the mechanical properties while maintaining a relatively good electrical conductivity. This paper describes the effect of several potential alloying elements (Cr, Nb, and Zr) on the microstructures and mechanical properties of Cu-6 pctAgin-situcomposites. The results reveal that the addition of both Cr and Nb refined the morphology of the Ag filaments and considerably improved the tensile strengths of the drawn Cu-Ag composites at large strains. Particularly, the ultimate tensile strengths of the Cu-6 pctAg-1 pctCr composites were improved by approximately 23 pct than that of the Cu-6 pctAg binary composites, with only a slight loss in conductivity. By contrast, the addition of 1 pctZr to the Cu-Ag composites had a negative effect on the morphology of the Ag filaments; it only improved the hardness at low drawing stains while reducing both the tensile strength and electrical conductivity.
10.1007-s11661-020-06107-2	5	materials; thermal; heat; properties; material; welding; sintering; fusion; strength; laser; heat sink; thermal conductivity; mechanical; sink; manufacturing	A three-dimensional heat transfer and material flow-based model using experimentally measured thermo-physical properties has been developed for friction stir welding (FSW) of Cu-0.8Cr-0.1Zr alloy. CuCrZr alloy is a precipitation-hardened copper alloy with good electrical and thermal conductivity and moderate strength at elevated temperatures. The temperature-dependent specific heat, thermal conductivity, and yield strength of the alloy were determined experimentally to develop a reliable and accurate numerical model. The results from numerical model were validated by performing suitable experiments for numerous tool rotational speeds and welding speeds during joining of 3-mm-thick CuCrZr alloy on a dedicated FSW machine. The temperature evolution across the welds was measured using thermocouples. The results from the developed numerical model were validated by comparing it with the measured weld thermal cycles, peak temperatures, and thermo-mechanically-affected zone (TMAZ) for various welds. Validation was also supported with microstructural evidences from the weld nugget zone and TMAZ. The developed model showed the capability to simulate FSW of CuCrZr alloy and predict the important results with reasonably good accuracy
10.1007-s11661-021-06224-6	12	thermodynamic; ternary; phase; data; experimental; equilibria; phase equilibria; liquid; binary; experimental data; calculated; phases; literature; model; calphad	In this paper, eight solid-state diffusion couples in fcc ternary Cu-Ni-Al alloys at 1073, 1173 and 1273 K were prepared, and the corresponding composition profiles were measured with an electron probe microanalyzer (EPMA) technique. Based on the measured composition profiles and HitDIC software, a set of reliable atomic mobility descriptions in the fcc Cu-Ni-Al system were directly established, from which the composition- and temperature-dependent interdiffusion coefficient matrices were evaluated. Then, the three-dimensional (3D) main interdiffusivity surfaces for fcc Cu-Ni-Al systems were constructed. The diffusion rate of Al is faster than that of Ni. Both the main interdiffusivities of Al and Ni increase with the increase of Al concentration but decrease with Ni concentration. The reliability of the evaluated interdiffusivities was first validated by reproducing the measured composition profiles and interdiffusion fluxes. After that, the interdiffusivities and corresponding uncertainties at intersection points of diffusion couples were evaluated by using the Matano-Kirkaldy method combined with distribution functions. Especially all the interdiffusion coefficients estimated from the present mobility parameters are within the bounds of the uncertainties, which further quantitatively verified the reliability of the present mobility descriptions. The accuracy of the as-determined mobility is further highlighted via combining with the reported thermodynamic descriptions, which enables an accurate prediction of the volume of Ni3Al precipitates in the Cu-Ni-Al alloy during artificial aging. The present work indicates that with the accurate thermodynamic as well as boundary mobility descriptions, reliable ternary mobility descriptions can be achieved by combining the diffusion couple experiments with the HitDIC modeling.
10.1007-s11661-021-06435-x	-1		Microstructural response and variations in strength and electrical conductivity of a Cu-20 at. pct Ni-6.7 at. pct Al alloy during isothermal aging at temperatures from 723 K to 1023 K (450 degrees C to 750 degrees C) were investigated to discuss the age-induced precipitation behavior and strengthening mechanism. At all aging temperatures, fine spherical gamma '-Ni3Al particles were found to nucleate coherently with parent Cu grains by continuous precipitation and then grew gradually by Ostwald ripening. Domains with a high density of twins developed at grain boundaries during aging below 873 K (600 degrees C) followed by cellular components composed of fiber-shaped gamma '-Ni3Al and Cu solid solution phases at the domain boundaries later. Both the domains and cellular components were suppressed at aging above 923 K (650 degrees C). The age-induced strengthening principally resulted from fine dispersion of gamma '-Ni3Al coherent particles in the grains. The precipitation strengthening by the fine gamma '-Ni3Al coherent particles exhibited a maximum at an aging temperature of 873 K (600 degrees C), resulting in excellent mechanical properties such as a high hardness of 340 +/- 7 HV and an ultimate tensile strength of 980 +/- 14 MPa, which are comparable to those of other commercial age-hardened Cu-Be, Cu-Ni-Si, and Cu-Ti alloys.
10.1007-s11661-021-06502-3	-1		This work studies the solidification processes and microstructures of Zr55Cu30Al10Ni5 (at. pct) and Cu64Zr36 (at. pct) amorphous alloy sheets fabricated by twin-roll strip casting. A largely excessive volume was frozen in the alloy during the twin-roll strip-casting process, resulting in many soft regions and the inhomogeneity of the microstructure in the amorphous alloy sheet. The results provide insights into the solidification process of amorphous alloys and guidelines for adjusting their microstructure.
10.1007-s11661-022-06609-1	-1		Laminated Cu-Pb-Sn/Steel composites (C/SC) with Pb-rich secondary phases (SPs) in different morphology were prepared by solid-liquid continuous casting compositing (S-LC). SPs transform from network to rod-like to abnormally coarsening morphology with casting temperatures increasing from 1473 K to 1513 K to 1533 K. The prepared C/SC possesses a high-quality interface and high bonding strength due to the existence of the Cu/Fe interdiffusion layer with a thickness of about 0.75 mu m. The thickness calculated by CALPHAD is in the range of 0.38 to 1.35 mu m which is consistent with experimental results. The mechanical properties of C/SC present a high correlation with the morphology of SPs. C/SC with network and rod-like SPs, respectively, shows the lowest and highest plasticity and carrying capacity. Finite element analysis (FEA) was conducted to simulate the plastic deformation of C/SC. By comparing the experiments with FEA results, the network SPs with high continuity were proven to significantly decrease the tensile strength and elongation of Cu-Pb-Sn alloy layer of C/SC by splitting the matrix. C/SC with rod-like SPs presents the highest mechanical performance due to the minimal damage to matrix. (C) The Minerals, Metals & Materials Society and ASM International 2022 [GRAPHICS]
10.1007-s11661-022-06927-4	-1		In this study, the effect of accelerated Fe-rich precipitation caused by Ag addition on the refinement of solidified microstructure and the improvement of electrical, mechanical, and magnetic properties of Cu-10Fe alloys was systematically investigated. Firstly, the quadruple refinement of Cu grains, micron-sized primary Fe-rich spheres and dendrites, and nano-sized Fe-rich precipitates in as-cast Cu-10Fe alloys was induced by the accelerated Fe-rich precipitation. Secondly, the saturation magnetization of as-cast Cu-10Fe alloys was improved, which is mainly dominated by the accelerated precipitation of micron-sized Fe-rich spheres and dendrites, rather than that of nano-sized Fe-rich precipitates. Moreover, the yield strength of cold-rolled Cu-10Fe alloys was increased, which can be attributed to the accelerated precipitation of nano-sized Fe-rich phases and their pinning effect on dislocation movement during cold-rolling. In the end, the synergistic enhancement of strength, ductility, and electrical conductivity of aged Cu-10Fe alloys was obtained by Ag addition, which guides the preparation of high-performance Cu-Fe alloys.
10.1007-s11661-022-06938-1	-1		Conductive spring wires for application in electrical components require high strength, high electrical conductivity, and convenient manufacturability. Copper-indium (Cu-In) solid solution alloys are suitable candidates for such wires because they exhibit effective solid solution strengthening without significantly decreasing the conductivity. Herein, we systematically investigate the microstructure of Cu-In alloy wires fabricated by severe drawing, along with their mechanical and electrical properties. During the initial drawing stages, high-density deformation twins are generated in the Cu-In alloy because the In solute efficiently reduces the stacking fault energy (SFE) of the Cu matrix. These deformation twins promote grain refinement during subsequent drawing. The Cu-5.0 at. pct In alloy wire, drawn severely to an equivalent strain of 4.61, possesses ultrafine grains measuring 60 to 80 nm with a high density of dislocations, resulting in excellent yield strength, tensile strength, and conductivity of 1280 MPa, 1340 MPa, and 24 pct relative to the International Annealing Cu Standard, respectively. These properties were comparable to those of age-hardenable Cu-Be and Cu-Ti alloys; thus, our results demonstrate that tuning the In content of the Cu matrix to reduce the SFE and optimizing the deformation strain to refine the grain size significantly improves the performance of alloy wires.
10.1007-s11661-023-07053-5	-1		This research investigates the effect of pre-straining, heat input, and cooling media on the microstructure and mechanical properties of friction-stir-processed brass. The findings show that in the pre-strained Cu-Zn alloy, applying very low heat and high heat inputs results in longitudinal groove defect formation and heterogeneity in the microstructure of the friction stir processed samples, respectively. Also, extremely high shear deformation during friction stir processing at a rotational speed of 800 rpm and a traverse speed of 100 mm/min under water cooling media results in the formation of fine equiaxed grains (2.2 +/- 0.4 mu m), ultimate tensile strength (458.2 MPa), yield strength (371.2 MPa), and elongation 10.1 pct. By simultaneous applying pre-rolling and friction stir processing, the grain size of Cu-Zn alloy's base metal decreases by 95.4 pct. The micro void formation and non-uniformity of the hardness distribution resulting from the heterogeneity in the microstructure of the sample processed at maximum heat input led to minimum tensile strength (249.6 MPa) and elongation (2.1 pct).
10.1007-s11661-023-07165-y	-1		In this work, two different types of post-heat treatment processes were developed for additively manufactured CuCrZr alloy. The effect of post-heat treatment on the microstructure and properties of as-built CuCrZr alloy was studied in detail. After the direct aging of the as-built samples, the cellular substructure was preserved and a large number of fine Cu4Zr and Cr particles were precipitated in the matrix. However, after solid solution and age-hardening treatment, the grains in the sample coarsened to hundreds of microns and the annihilation of the cellular substructure occurred. Compared with the samples after solid solution and age-hardening treatment, the directly aged samples had an excellent combination of hardness (191 & PLUSMN; 7 HV), strength (513 & PLUSMN; 8 MPa) and electrical conductivity (82.2 & PLUSMN; 1.5 pct IACS). The high strength of the directly aged samples can be attributed to the enhancement of the strengthening mechanism of the precipitated particles and the retention of the cellular substructure. In addition, the reduction of solid solution atoms would significantly weaken the electron scattering effect, thereby improving the electrical conductivity.
10.1007-s11661-024-07341-8	6	grain; deformation; strain; strength; dislocation; cu-; tensile; size; ecap; grain size; sfe; ductility; hardening; high; stress	In this investigation, annealed Cu-0.13Sn alloys i.e., as-received samples were subjected to room-temperature rolling (RTR) at reduction ratios (RR) of 40 and 75 pct. Electron backscattered diffraction (EBSD) and transmission electron microscopy (TEM) was used to discuss the microstructure evolution in the as-received and RTR samples. RTR deformation resulted in the formation of Copper-type shear bands (SBs). An unusual phenomenon of static recrystallization (SRX) at room-temperature (RT)/self-annealing was observed in the severely deformed Cu-0.13Sn alloy. SBs and deformed grain boundaries (GBs) were the main sites with high levels of stored energy (SE), and new grains were nucleated in those regions via discontinuous SRX (DSRX) in the RTR samples. Continuous SRX (CSRX) was observed in grains nucleated inside the deformed grains. The fraction of SBs was increased with increases in the RR, and visco-plastic self-consistent (VPSC) modelling was used to predict the texture of the SBs in the severely deformed Cu-0.13Sn alloy. Microstructural heterogeneities had a significant effect on the evolution of the crystallographic texture in as-received and RTR samples. Under low strain (40 pct RR), a Copper-type texture was observed, whereas the severely deformed sample (75 pct RR) showed strong Copper and S components, but weak Brass component. Self-annealed grains in the SB regions and in the deformed GB regions led to the evolution of strong Copper and Rotated Cube components, but weak Brass component.
10.1007-s11661-024-07398-5	14	strength; properties; conductivity; electrical; mechanical; cu-; grain; mpa; electrical conductivity; aging; precipitation; phase; mechanical properties; tensile; phases	Cu-Ag in-situ composites, renowned for their amalgamation of high strength and superior electrical conductivity, find extensive applications as conductors in high field magnets. This investigation delves into the microstructural intricacies and mechanical characteristics of Cu-18 pct Ag (wt pct) in-situ composites following the incorporation of alloying elements (Nb, Cr, and Zr) via a comprehensive process involving casting, heat treatment, and cold deformation. The outcomes reveal that the introduction of Nb or Cr elements intricately refines the Cu dendrites and eutectic phase. Simultaneously, the Cu matrix experiences fortification through the inclusion of Nb or Cr particles, imparting notable improvements in mechanical properties. Remarkably, Cr addition exhibits the most pronounced impact on elevating both ultimate tensile strength and hardness. Under a deformation rate (eta) of 5.28, the ultimate tensile strength surges by 21.00 pct compared to that of the Cu-18 pct Ag alloy, albeit with a marginal 7.36 pct decrease in conductivity for the Cu-18 pct Ag-1 pct Cr alloy. The introduction of Nb augments ultimate tensile strength by 12.23 pct, with no apparent impact on conductivity under identical deformation conditions. In contrast, Zr addition significantly disrupts the precipitation of the Ag phase, fostering the formation of the intermetallic compound Cu4AgZr. This disruption induces a reduction in both mechanical properties and conductivity, leading to embrittlement at high drawing strains.
10.1007-s11661-024-07466-w	14	strength; properties; conductivity; electrical; mechanical; cu-; grain; mpa; electrical conductivity; aging; precipitation; phase; mechanical properties; tensile; phases	The effects of cryorolling (CR), room-temperature rolling (RTR), and subsequent aging on the mechanical, electrical, and wear characteristics of Cu-6Ni-6Sn alloys were examined. Compared to the RTR specimens, those subjected to CR displayed a higher dislocation density and a greater number of nanosized deformation twins. The CR facilitated the uniform and dense formation of precipitates, enabling the CR-treated alloys to achieve an optimal balance of strength (1004 MPa), electrical conductivity (11.8 pct IACS), and wear resistance.
10.1007-s11661-024-07507-4	12	thermodynamic; ternary; phase; data; experimental; equilibria; phase equilibria; liquid; binary; experimental data; calculated; phases; literature; model; calphad	The phase equilibria of the Cu-Ti-V system were investigated via key experiments coupled with thermodynamic modeling. The isothermal sections at 600 degrees C, 700 degrees C, and 800 degrees C were constructed using X-ray diffraction (XRD) and scanning electron microscopy with energy-dispersive X-ray spectroscopy (SEM/EDS). The solubilities of Cu in the (beta Ti, V) phase and V in intermediate phases Cu4Ti, Cu3Ti2, Cu4Ti3, CuTi, CuTi2, and CuTi3 were determined. Based on the thermodynamic descriptions of three binary subsystems and the experimental data, the thermodynamic assessment of the Cu-Ti-V system was carried out by means of the CALPHAD (CALculation of PHAse Diagrams) method. A set of thermodynamic parameters for the Cu-Ti-V system was obtained and the calculated phase equilibria were consistent with the experimental results. The liquidus projection and the reaction scheme of the Cu-Ti-V system were constructed. This work provides important phase equilibria and thermodynamic data for the composition and process design of new copper alloys.
10.1007-s11661-024-07566-7	14	strength; properties; conductivity; electrical; mechanical; cu-; grain; mpa; electrical conductivity; aging; precipitation; phase; mechanical properties; tensile; phases	Innovations in electronic devices and their capabilities have driven the demand for improved conductive materials relevant to device fabrication. To gain insights on developing solid solution-type Cu alloy thin wires with a superior balance of strength and conductivity, this study investigated variations in the microstructures and properties of pure Cu wires and Cu-5 at. pct Zn, Cu-5 at. pct Al, and Cu-5 at. pct In alloy wires during intense drawing and analyzed the effects of stacking-fault energy (SFE) of Cu alloys on their microstructural evolution. During the initial drawing stages, lower SFE Cu-5 at. pct Al and Cu-5 at. pct In alloys yielded more high-density deformation twins than pure Cu and Cu-5 at. pct Zn. Deformation twins promoted grain refinement during drawing. Effective grain refinement and dislocation accumulation during drawing in low-SFE Cu alloys substantially strengthened them without adversely impacting electrical conductivity. During intense drawing in the Cu-5 at. pct In alloy wires, ultrafine fibrous grains (diameter similar to 80 nm) and a high-dislocation density yielded excellent tensile strength and conductivity. These results indicate that adjusting the solute element content in Cu matrix to reduce SFE and optimizing deformation strain via wire drawing significantly improve alloy wire performance.
10.1007-s11661-024-07654-8	-1		High magnetic field-assisted solidification holds immense promise in manipulating the microstructures and properties of metallic materials. However, solute migration and redistribution at the solid-liquid interface during such solidification are not thoroughly understood at a microscopic level. To elucidate the mechanisms involved, directional solidification and quench experiments were performed with Cu-Ag eutectic alloys under various magnetic fields and solidification rates. The results showed that a high magnetic field intensified the solute enrichment of the liquid phase in front of the two eutectic phases simultaneously but to different extents. By calculating the solute partition coefficients, increased solute segregation can be confirmed under a high magnetic field. The changes in solute migration and redistribution behavior were attributed to the magnetic force and the Lorentz force, which can participate in a cooperative or contrary relationship depending on the magnetic susceptibility of the solute. This research helps clarify the solute redistribution behavior during eutectic alloy solidification under a high magnetic field, providing further theoretical basis for the modulation of alloy microstructures and properties by implementing high magnetic field-assisted solidification. (c) The Minerals, Metals & Materials Society and ASM International 2024
10.1007-s11661-025-07760-1	-1		In this study, microstructure, corrosion behavior, and tribological properties of Cu-GO nanocomposites produced by accumulative roll bonding (ARB) process up to 4 cycles have been studied through microstructure observation, microhardness testing, pin-on-disk wear-testing, and electrochemical measurements in 3.5-wt pct NaCl solution. Microstructural studies show ARB can remarkably decrease the grain size and improve the dispersion of GO in the Cu matrix as well as the connection improvement between Cu layers. It is observed that the highest hardness value of about 140 HV is obtained with the increasing number of cycles up to 4 due to the strain-induced grain refinement and presence of secondary phase GO. Moreover, wear rate and weight loss of the samples were continuously decreased up to cycle 2 and after that they were grown and delamination wear became the dominant mechanism with increasing the ARB cycles. In addition, corrosion behavior shows that the corrosion current density (0.7 x 10-3 A cm-2) of the nanocomposite was decreased after 4 cycles and the best anti-corrosion property for forming the passive films was provided. The coarse microstructure in Cu-annealed sheet leads to accelerating galvanic corrosion.
10.1007-s11661-025-07850-0	-1		Technological advancement have increased the demand for materials with improved wear resistance, whilst maintaining cost-efficiency and environmental sustainability. Copper-based low-carbon steels have emerged as promising candidates to meet these requirements. This study investigates the dry sliding wear behaviour of two such steels with different Cu contents (LCu: 0.60 wt pct and HCu: 1.10 wt pct), quenched from various austenitization temperatures (820-920 degrees C, 0.5 hour soaking). The quenched structures primarily consist of martensite and bainite. Wear tests were conducted using a pin-on-disc tribometer under a normal load of 30 N and a sliding velocity of 1 m s(-1) at room temperature. The results show that wear performance is influenced by flash temperature variation, which alters the roughness and the nature of evolved oxides. The rise in flash temperature has been predicted through Greenwood-Williamson model. In 920 degrees C quenched specimens, a moderate increment in flash temperature develops thin (similar to 1 mu m), adherent Fe3O4 layers and dislocation substructures in the severely deformed zone, which together improve wear resistance, leading to a lower specific wear rate (SWR) of 0.42 x 10(-5) mm(3) m(-1) N-1. In contrast, enhanced flash temperatures in 820 degrees C quenched specimens lead to thicker (5-6 mu m), brittle and loosely attached FeO layers, reducing wear resistance and increasing SWR (0.95 x 10(-5) mm(3) m(-1) N-1). (c) The Minerals, Metals & Materials Society and ASM International 2025 [GRAPHICS] .
10.1007-s11663-004-0066-9	-1		A copper-nickel alloy has been prepared from an aqueous solution of the nitrates of copper and nickel, through co-formation of their ultrafine mixed oxides, by heating around 650 K followed by reduction with hydrogen at a very low temperature (below 623 K). The effect of temperature (473 to 623 K) on the kinetics of the hydrogen reduction of the co-formed oxides of Ni and Cu has been studied. The activation energy of the reduction reaction has been calculated and found to be 35.8 kJ/mole. A mechanism for the kinetics of the process has been suggested. It has been possible to get high-purity Cu-Ni alloy powder (50 at. pet each) free of any detectable oxygen, from their co-formed oxides, by hydrogen reduction at 623 K in less than 20 minutes. Although the X-ray analysis of the co-formed oxides has shown separate peaks for CuO and NiO, the alloy powder has exhibited a single peak with a d spacing lying in between those of Cu and Ni. It is suggested that the alloying of the two metals has taken place during the H-2 reduction of nanosized oxide particles of copper and nickel, prepared by the aforementioned chemical route. The alloy powder has been sintered at 1273 K. The density and hardness of the consolidated alloy have been measured and found to be close to the theoretical values. The alloy has also been subjected to cold reduction and annealing, in addition to metallograph examination and characterization by a scanning electron microscope (SEM), to confirm the homogeneity of the alloy.
10.1007-s11663-011-9510-9	2	corrosion; surface; film; electrochemical; films; spectroscopy; layer; current; solution; potential; resistance; composition; x-ray; ions; showed	In this article, the electrodeposition process of Cu-Sn alloy powders from tripolyphosphate (TPP)-based electrolytes was investigated as a function of deposition parameters. The effects of deposition parameters such as current density, electrolyte composition (Cu/Sn mole ratio), mechanical stirring speed, and temperature on the Cu content of alloy powder and cathodic current efficiency were evaluated using the response surface methodology (RSM). The empirical models developed in terms of deposition parameters were found to be statistically adequate to describe the process responses. The study revealed that as far as the copper content was concerned in the alloyed powders, all parameters selected had positive correlations. However, a high stirring speed and low current density led to a greater current efficiency. The morphology and chemical composition of the electrodeposited Cu-Sn alloy powders were investigated using scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDS), X-ray diffraction (XRD), and inductively coupled plasma (ICP) analysis. An SEM analysis showed that the powder morphology was affected considerably by the cathodic current density and stirring speed.
10.1007-s11663-014-0246-1	-1		In order to develop a new pyrometallurgical process for the elimination of detrimental arsenic and the recovery of precious elements, such as, silver, gold, and platinum from arsenic-rich copper-lead scraps, the phase relations in the Cu-Fe-Pb-As system saturated with carbon and the distribution of precious elements between the condensed phases generated during the equilibrium at high temperature were investigated. The investigation was carried out by performing a series of laboratory scale experiments using an electrical furnace at 1473 K (1200 degrees C), followed by the quenching of molten samples taken on the final stage. The samples obtained from the experiments were analyzed using electron probe X-ray micro analysis, inductively couple plasma, and carbon infrared spectrometry techniques. The results were discussed on the basis of the activity coefficient of arsenic, interaction parameters of minor components, and distribution parameters for precious metals in the three equilibrated alloy phases of lead-rich, copper-rich, and iron-rich that coexists in the corresponding miscibility gap. The present results suggest that the recovery of valuable silver and gold into the copper-rich alloy and lead-rich alloy phases and the elimination of arsenic and iron into the iron-rich alloy phase might be feasible. (C) The Minerals, Metals & Materials Society and ASM International 2014
10.1007-s11663-015-0382-2	-1		The dendritic structure in a cast Cu-12.6 wt pct Sn alloy can be transformed to a globular structure if the alloy is heat treated in the semisolid range. A Cu-12.6 wt pct Sn alloy has a wide solidification range which encourages the development of a cored dendritic structure during solidification. In order to transform it into a globular structure, heat treatment was carried out separately at three temperatures in the semisolid range, namely 1183 K, 1153 K, and 1123 K (910 A degrees C, 880 A degrees C, and 850 A degrees C) with corresponding liquid volume fractions of 50, 40, and 20 pct, respectively. An attempt was made to optimize the temperature and vol pct of liquid combination. It was observed that microstructural modification proceeded mainly through coarsening, fragmentation, and spheroidization of the dendrite arms. Semisolid heat treatment at 1123 K (850 A degrees C) for 2 hours with 20 vol pct liquid yielded the best result. This microstructure was compared with the microstructure developed by solid-state heat treatment at 1023 K (750 A degrees C) for 2 hours. Assessment of the structure-property co-relation demonstrated that hardness, yield stress, ultimate tensile stress, and toughness of the semisolid heat-treated samples were superior to those of subcritically annealed samples.
10.1007-s11663-015-0383-1	-1		The enthalpies of mixing of liquid Cu-Fe-Zr alloys were determined at 1873 K (1600 A degrees C) by using a high-temperature isoperibolic calorimeter. The measurements were performed along sections x (Cu)/x (Fe) = 3/1, 1/1, 1/3 in the composition range x (Zr) = 0 to 0.55. The limiting partial enthalpies of mixing of undercooled liquid zirconium in liquid Cu-Fe alloys are (-91.8 +/- A 8.4) kJ mol(-1) (section x (Cu)/x (Fe) = 3/1), (-94.1 +/- A 12.8) kJ mol(-1) (section x (Cu)/x (Fe) = 1/1), and (-107.3 +/- A 15.6) kJ mol(-1) (section x (Cu)/x (Fe) = 1/3). The integral mixing enthalpies are sign changing over the investigated composition range. The Redlich-Kister-Muggianu polynomial was used for the least square fit of the experimental results in order to obtain an analytical expression for the integral mixing enthalpy.
10.1007-s11663-016-0691-0	-1		This article deals with the effect of adding nano CeO2 to act as a grain pinner/refiner to a known Cu-Al-Ni shape memory alloy. Elements were taken in a predefined ratio to prepare 300 g alloy per batch and melted in an induction furnace. Casting was followed by homogenization at 1173 K (900 A degrees C) and rolling to make sheets of 0.5-mm thickness. Further, samples were characterized for microstructure using optical and electron microscope, hardness, and different phase studies by X-ray and transformation temperatures by differential scanning calorimetry. X-ray peak broadenings and changes were investigated to estimate the crystallite size, lattice strain, and phase changes due to different processing steps. A nearly uniform distribution of CeO2 and better martensitic structure were observed with increasing CeO2. The addition of CeO2 also shows a visible effect on the transformation temperature and phase formation.
10.1007-s11663-017-1017-6	2	corrosion; surface; film; electrochemical; films; spectroscopy; layer; current; solution; potential; resistance; composition; x-ray; ions; showed	Electrochemical behavior of Nd was studied in NaCl-KCl melt on W and Cu electrodes via cyclic voltammetry and chronopotentiometry. Generally, the reduction of Nd3+ takes place in two consecutive steps in molten chlorides, such as LiCl-CaCl2, LiCl-BaCl2, CaCl2-NaCl, LiCl-KCl melts. However, the reduction of Nd3+ ions was found to be through a one-step process: Nd3+ + 3e(-) -> Nd. The co-reduction behavior of Nd3+ and Cu2+ ions and the mechanisms of alloy formation were investigated in NaCl-KCl melt on W electrodes at 988 K (715 A degrees C). Four potential plateaus corresponding to four different kinds of Cu-Nd intermetallic compounds were detected. Cu-Nd alloys were prepared on Cu electrodes at 988 K (715 A degrees C) and 1143 K (870 A degrees C). At 988 K (715 A degrees C), Cu5Nd phase was identified by X-ray diffraction. The morphology and micro-zone chemical analysis of the alloys were characterized by scanning electron microscopy equipped with energy-dispersive spectrometry. The alloy film was observed on the Cu electrodes. Moreover, at 1143 K (870 A degrees C), a globate bulk Cu-Nd alloy with Cu5Nd, Cu4Nd, Cu2Nd, CuNd, and Cu phases, as liquid in the melt, was obtained at the bottom of the crucible.
10.1007-s11663-017-1103-9	0	solidification; phase; magnetic; magnetic field; undercooling; field; liquid; separation; peritectic; immiscible; cu-; dendrite; phase separation; microstructure; primary	The thermal conductivity of molten Cu-Co alloy with different compositions around the liquidus line temperature was measured by the periodic laser-heating method using an electromagnetic levitator superimposed with a static magnetic field to suppress convection in a levitated droplet sample. During the measurement, a static magnetic field of 10 T was applied to the levitated droplet. To confirm that the strength of the static magnetic field was sufficient to suppress convection in the droplet, numerical simulations were performed for the flow and thermal fields in an electromagnetically levitated droplet under a static magnetic field, and moreover, for the periodic laser-heating method to determine the thermal conductivity. It was found that the thermal conductivity of molten Cu-Co alloy increased gradually with increasing Cu composition up to 80 at. pct, beyond which it increased markedly and reached that of pure Cu. In addition, it was found that the composition dependence of the thermal conductivity can be explainable by the Wiedemann-Franz law.
10.1007-s11663-018-1400-y	13	clusters; atomic; glass; atoms; composition; dynamics; metallic; icosahedral; glasses; simulations; molecular; cu-zr; molecular dynamics; metallic glasses; structural	The liquid phase thermodynamics of mixing of the copper-aluminum binary system are investigated as a function of temperature and composition using the electrochemical potential difference method. A copper-selective beta alumina is used as a solid electrolyte, synthesized through ion exchange, sintering from base oxide powders, and the floating zone method of crystal growth . Measured thermodynamics of mixing data were used to inform short-range ordering in copper-aluminum melts through Darken's factor for excess stability and Bhatia-Thornton structure factors, revealing a strong departure from ideality and pronounced ordering. Mixing properties were used to predict viscosity and self-diffusion coefficients. Features observed in calculated electronic entropy of mixing for copper-aluminum were compared with trends in viscosity, demonstrating the utility of electronic properties of mixing in the description of structure-properties in this liquid binary system.
10.1007-s11663-019-01638-5	-1		Normal spectral emissivity of molten Cu-Fe alloy with different compositions was measured at the wavelength of 807 nm using an electromagnetic levitator superimposed with a static magnetic field, which is capable of producing accurate normal spectral emissivity data because the applied static magnetic field suppresses translational and surface oscillations of a levitated sample to consequently reduce measurement uncertainties. Cu-Fe alloy samples used in this study were Cu97Fe3, Cu93Fe7, Cu92Fe8, Cu90Fe10, Cu80Fe20, and Cu70Fe30. The strength of the static magnetic field and temperature ranged from 3.0 to 3.5 T and 1350 to 1750 K, respectively. The measured normal spectral emissivity indicated negligible temperature dependence in a wide temperature range. In contrast, the compositional dependence indicated a distinct tendency in which the emissivity increased markedly with the composition of Fe up to 10 at pct.
10.1007-s11663-021-02063-3	0	solidification; phase; magnetic; magnetic field; undercooling; field; liquid; separation; peritectic; immiscible; cu-; dendrite; phase separation; microstructure; primary	Direct numerical simulations were carried out to investigate three-dimensional, unsteady magnetohydrodynamic (MHD) convection in a spherical electromagnetically levitated molten Cu-Co droplet with a diameter of 5 mm under different strengths of the static magnetic field. The strength of the static magnetic field ranged from 0 to 3 T. MHD convection under lower static magnetic fields presented turbulent flow. The velocities in the levitated droplet decreased with increasing strength of the static magnetic field. At more than 1.5 T, the convective flow pattern became axisymmetric and the turbulent energy reached almost zero, i.e., MHD convection presented laminar flow. Comparisons of the present numerical results with past experimental results demonstrated that the marked change in phase separation structures in undercooled Cu-Co alloys at 1.0 to 1.5 T was closely related to the laminar-turbulent transition of MHD convection in the levitated droplet.
10.1007-s11663-021-02275-7	-1		Sodium sulfate accumulation in the water system is a common problem in the production of primary metals from sulfide minerals. In flash smelting-flash converting copper smelters, when molten copper matte quenched in industrial water to produce matte granules, Na2SO4 precipitated and entered the system, which had negative influence on the matte converting process. The reaction behaviors of copper matte powder containing Na2SO4 have been studied through thermodynamic calculation and single-particle experiments. Calculated results showed that a liquid sulfate phase, Na2S containing copper matte, and Cu-Na alloy may form in the processing conditions of the converting process. The influence of the Na2SO4 dosage, fluxing conditions, and processing temperature has been systematically studied, and the results obtained showed that: (1); Na2SO4 physically precipitated on matte particles, and the Cu-Na alloy phase was found within copper phase in reacted particles; (2); Na2SO4 contamination hindered oxygen transfer by forming a low melting sulfate phase, and the de-sulfuration rate of matte powder changed dramatically along with the variation in Na2SO4 amount; (3); CaO flux was able to promote the converting reactions and Na2SO4 transformation; (4); Na2SO4 melt and formed a sulphate layer on matte particles at 1000 degrees C, Cu-Na alloy phase was found in samples collected at 1200 degrees C, and Cu-Na-O phase was detected in blister copper at 1600 degrees C.
10.1007-s11663-024-03213-z	0	solidification; phase; magnetic; magnetic field; undercooling; field; liquid; separation; peritectic; immiscible; cu-; dendrite; phase separation; microstructure; primary	Two ultrasonic modes, i.e., continuous and pulsed ultrasounds, were introduced into the directional solidification process of Cu68.3Al27.6Ni4.1 alloy. A columnar-to-equiaxed structure transition occurred to primary beta(Cu3Al) phase within continuous ultrasonic field, which was accompanied with a grain size reduction by 7.5 times. Under pulsed ultrasound, beta phase maintained the fine columnar structures with a similar grain size. In the former case, numerous beta phase nucleation sites formed ahead of solid/liquid (S/L) interface because of the large local undercoolings induced by transient cavitation. Meanwhile, intensive acoustic streaming suppressed the liquid temperature gradient from 120 to 85 K/cm, which interrupted the solute transportation along heat flow direction and resulted in equiaxed microstructures. Under the intermittent ultrasonic action in the latter case, fewer nucleation sites were generated near S/L interface but small columnar beta grains were split from the original ones under stable cavitation. Since no steady convection was driven, the liquid temperature gradient of 110 K/cm remained almost constant, making those grains grow into refined columnar structures. Under the action of pulsed ultrasound, the yield strength was enhanced by a factor of 1.5 because of grain refinement strengthening, together with 94 pct shape recovery rate due to columnar grain structures.
10.1007-s11663-024-03381-y	-1		The production of copper based on a direct-to-blister flash smelting process made it necessary to introduce the technology for the reduction of flash smelting slag and subsequent refining of the resulting Cu-Fe-Pb alloy. Refining of Cu-Fe-Pb alloy produces a converter slag containing 7 divided by 25 wt pct Cu, 3 divided by 20 wt pct Fe , and 15 divided by 45 wt pct Pb. This material is directed to the reduction (de-coppering) process, which allows the recovery of copper in the form of Cu-Pb alloy as well as the removal of lead from the copper material cycle in the form of lead-bearing material. The copper recovery rate in the form of Cu-Pb alloy depends on a number of factors, of which one of the primary ones is the viscosity of the medium (slag), which determines the rate of coalescence and sedimentation of the reduced metal droplets. The investigations on how the degree of reduction of metal oxides from the converter slag affects its viscosity are presented in the study. Viscosity tests were conducted in the range of 1000 divided by 1450 degrees C and showed that the main factor affecting viscosity is the Cu2O content in the slag. Slags directed to the reduction process with a high Cu2O content have a lower viscosity than slags after the reduction process, which is due to a decrease in the copper oxide content of the slag. The viscosity of slags after reduction depends on the PbO content, the higher the PbO content the lower the slag viscosity. Furthermore, studies have shown that the viscosity of slags can be reduced by adding CaO to the slag.
10.1007-s11663-024-03418-2	-1		Metal matrix composites (MMCs) have attracted the interest of researchers due to its potential to improve tribological and mechanical properties. This study investigates the influence of ceramic reinforcement of TiC/CaF2 on physical, mechanical and friction characteristics of CuNi alloy/TiC MMCs. The composites reinforced with CaF2 particles (0, 4, 8 wt pct) were developed by powder metallurgy, using solid-state sintering. The homogeneous dispersion of TiC/CaF2 particles in the Cu-Ni matrix was confirmed by microstructure analysis. The CuNi/10 wt pct TiC composite exhibited the highest density (7.32 g/cm3) and hardness (40.6 HV/0.1). Among all the composites tested, the lowest COF of (0.21) was observed for CuNi + (10 wt pct)TiC + (8 wt pct)CaF2. The COF of the CuNi + (10 wt pct)TiC + (8 wt pct)CaF2 composite is reduced by 62.5 pct compared to the current material. Friction-induced chemical reactions resulted in the development of oxides (Cu2O, NiO, Fe2O3, and TiO2 phases) at the contact interface, substantially influencing tribological characteristics and wear mechanisms. Delamination, tribo-oxidation wear, adhesive wear, and abrasive wear were the main wear mechanisms observed in the fabricated composites.
10.1007-s11663-025-03449-3	-1		Growth behaviors of primary CuTi in a hypoeutectic Cu-53 at. pct Ti alloy are unveiled in situ using confocal scanning laser microscope at a cooling rate of 60 K/minutes. Primary CuTi grows helically from the liquid. Furthermore, growth rate of primary CuTi is determined to be 2.90 mu m/seconds. Post-solidification examination reveals that growth mechanism of primary CuTi obeys the terrace-ledge-kink model. Our findings may offer a viable solution toward rational design of Cu-Ti alloys.
10.1007-s11663-025-03489-9	-1		In this study, vacuum distillation of copper-bismuth and copper-bismuth-silver alloys was conducted under the conditions of temperature of 1073-1273 K and system pressure of 3-5 Pa. bismuth was thoroughly separated from copper by a single-stage distillation of copper-bismuth alloy at 1273 K and 3-5 Pa. The content of copper in the residue is 98.94 wt pct, while the content of bismuth in the volatile is 96.30 wt pct. In the temperature range of 1098-1198 K, the content of bismuth in the volatiles was remained above 95 wt pct, and the contents of silver and copper in the volatiles were less than 0.1 wt pct when vacuum distillation was conducted on copper-bismuth-silver alloy. This indicates that bismuth was effectively separated from copper and silver by a single distillation. The activity of components of copper-bismuth alloy was calculated using Molecular Interaction Volume Model and Modified-Molecular Interaction Volume Model. The prediction deviation of Modified-Molecular Interaction Volume Model is smaller than that of Molecular Interaction Volume Model. Based on the Modified-Molecular Interaction Volume Model and vapor-liquid equilibrium theory, the vapor-liquid equilibrium value of copper-bismuth and copper-bismuth-silver alloys was predicted and the corresponding vapor-liquid equilibrium phase diagram was drawn. The predicted vapor-liquid equilibrium value are in good agreement with the experimental data determined in this study. This study provides a new method and reliable model for efficient separation of copper-bismuth and copper-bismuth-silver alloys by vacuum distillation.
10.1007-s11663-025-03737-y	14	strength; properties; conductivity; electrical; mechanical; cu-; grain; mpa; electrical conductivity; aging; precipitation; phase; mechanical properties; tensile; phases	In this study, Cu-based electrical contact materials reinforced with high-entropy alloy particles of CuCrNiCoFe were successfully prepared by combining high-energy ball milling and spark plasma sintering (SPS) technology. The microstructure, fundamental physical and mechanical properties of the novel Cu-10HEAs samples were investigated, and their arc erosion behavior was evaluated. After sintering using SPS, the material exhibits excellent comprehensive performance with a conductivity of 38.2 pct IACS, hardness of 72.3 HV, and density of 8.79 g/cm3. As the number of vacuum arc breakdown experiments increases, the arc-eroded region progressively expands from the edge region to encompass the entire surface of the HEAs phase. The Cu-10HEAs novel samples exhibit characteristics of arc confinement during vacuum arc breakdown testing. After 500 breakdown tests, the breakdown voltage only slightly decreased from 55.49 to 54.12 kV, indicating strong voltage resilience. Meanwhile, the samples demonstrate excellent resistance to arc erosion, with a relatively flat profile in the arc-affected area and minimal splash erosion.
10.1007-s11664-004-0110-1	4	transformation; martensite; martensitic; phase; shape; beta; memory; shape memory; temperature; temperatures; martensitic transformation; gamma; transformation temperatures; effect; thermal	The effects of grain size, volume fraction of the alpha (fcc) phase in the beta (bcc) matrix, and thermal stability on low thermal expansion (LTE) properties of Cu-Zn-Al shape memory (SM) alloys induced by cold rolling were investigated by dilatometry, optical microscopy, differential scanning calorimetry, and electrical conductivity measurements. The alloys with the larger grains showed a superior two-way memory (TWM) effect; wider LTE temperature intervals with excellent thermal stability under 80 degreesC. The alpha + beta two-phase alloys also exhibited a good combination of cold workability and LTE properties. These results suggest that the Cu-Zn-Al alloys with high electrical conductivity of about 20% International Annealed Copper Standard (%IACS) have high potential as a new class of Invar alloys that can be applied in various fields.
10.1007-s11664-006-0158-1	-1		The precipitation products of a Cu-1.5Ni-0.32P (wt%) alloy isochronally aged at 400 degrees C and 600 degrees C were investigated by transmission electron microscopy (TEM). There are two different sizes of precipitates formed in the 600 degrees C aged specimen. Large precipitates appear to be lath, the length of which varies from 100 nm to 500 nm, whereas small dotty contrasts around 10 nm in diameter are uniformly distributed in the matrix. Only small dotty contrasts are observed after 400 degrees C aging. In the composition range 0-33.3 at%P, both the previous studies and the calculated Ni-P binary phase diagram indicated that the possible nickel phosphide phases are Ni3P, Ni12P5, Ni5P2, and Ni2P. However, selected area electron diffraction (SAED) pattern analysis in conjunction with energy dispersive x-ray spectroscopy (EDS) identified the large lath precipitates as Ni12P5 phase. On the other hand, the small precipitates could not be analyzed by EDS due to thinness; thus, the structure is estimated to be a Ni5P4 phase from the relationships between d-spacing and angles between planes measured from a selected area diffraction pattern.
10.1007-s11664-006-0296-5	-1		The current study investigates the effects of insoluble substances (W and Mo) in pure Cu films on the thermal stability, microstructure, and electrical properties of the films. The results can be used to assess the feasibility of the barrierless Cu film in the metallization process. The films investigated were deposited using magnetron sputtering onto the barrierless Si (100) substrate and then annealed between 400 degrees C and 450 degrees C in vacuum for long periods of time. After annealing, the film properties were examined by x-ray diffraction (XRD), the four-point probe method, leakage current measurements, and focused ion beam (FIB) analysis. The results indicate that no detectable copper silicide is formed after 48-h annealing of Cu(W) films at 400 degrees C. In contrast, for the Cu(Mo) film, copper silicide is formed after 18-h annealing at the same temperature and hence electrical properties are poor. This evidence suggests that the Cu(W) film has better thermal stability during long periods of annealing and is suitable for an advanced barrierless metallization process.
10.1007-s11664-007-0270-x	-1		Tin is widely used as a coating material for copper metal in the electronics industry where tin whisker growth is a concern because it affects the reliability of electronic devices. Because whisker growth reduces joint reliability, it is important to monitor the growth Of CU3Sn and CU6Sn5, which is usually done by using an X-ray diffraction method to estimate the thickness of the tin layer. In this study, we use the sequential electrochemical reduction analysis (SERA) technique to measure the thickness of layers of pure tin, CU6Sn5, and CU3Sn. We also discuss the depletion rate of tin layers at high-temperature aging and the growth of these intermetallics.
10.1007-s11664-008-0394-7	-1		Copper thin films with high conductivity and good resistance to electromigration can be used in advanced electronic devices. However, the poor corrosion resistance of copper must be overcome. This work elucidates the possibility of using a self-forming passivation layer to prevent copper oxidation in lightly indium-doped copper thin films deposited directly on glass substrates and annealed under various oxygen atmospheres. The resistivity of the studied film declined gradually as the film was annealed at an elevated temperature because of the grain growth of the Cu film and the precipitation of indium from the In-doped Cu thin film, as revealed by X-ray diffraction, four-point probe measurements, and transmission electron microscopy. A copper film with high indium content exhibited superior passivation when the film was annealed in an oxygen-rich ambient, but it exhibited high resistivity because of its high indium content. The electrical and passivation properties demonstrated that indium is a promising alloying element for use in copper films for future metallization structures and thin-film transistors.
10.1007-s11664-013-2695-8	12	thermodynamic; ternary; phase; data; experimental; equilibria; phase equilibria; liquid; binary; experimental data; calculated; phases; literature; model; calphad	We investigated the phase equilibria in the Cu-Ni-Sb ternary system at 800A degrees C, 900A degrees C, 1000A degrees C, and 1100A degrees C using equilibrated ternary alloys by optical microscopy, electron probe microanalysis, energy-dispersive spectroscopy, and x-ray diffraction analysis. Based on the experimental phase equilibria data, the Cu-Ni-Sb ternary system was thermodynamically optimized by calculating phase diagrams using the CALPHAD method. Substitutional solution and sublattice models were used to describe the solution and intermediate phases, respectively. The self-consistent parameters describing the Gibbs energy of each phase in the Cu-Ni-Sb system were optimized, obtaining reasonable agreement between the calculated results and most of the experimental data.
10.1007-s11664-014-3018-4	-1		This work revealed that the Cu-deficient ternary compounds Cu3-x SbSe4 free of Te and Pb exhibit enhanced thermoelectric performance. Cu3-x SbSe4 (x = 0, 0.025, 0.050, 0.075) polycrystalline materials with high phase purity were fabricated by a facile method combining mechanical alloying and spark plasma sintering. Effects of Cu deficiencies on crystal structures, microstructures, element chemical states, and thermoelectric properties were systematically studied. High carrier concentration was obtained for the compositions Cu2.95SbSe4 and Cu2.925SbSe4 due to additional Cu vacancies, contributing to a remarkable increase in electrical conductivity. Together with a satisfactorily large Seebeck coefficient above 300 mu V/K, a high power factor of about 890 mu W/m-K-2 at 523 K was achieved for Cu2.95SbSe4 and Cu2.925SbSe4, almost 60% larger than that of the stoichiometric sample with x = 0. The maximum ZT value was increased to 0.50 at 673 K in the Cu2.925SbSe4 sample sintered at a high temperature (703 K); this is the highest value reported so far for the undoped Cu3SbSe4 system.
10.1007-s11664-015-3810-9	8	hot; deformation; strain; strain rate; dynamic; hot deformation; recrystallization; dynamic recrystallization; flow; rate; flow stress; compression; constitutive; degrees; stress	The effects of strain rate and load direction on the thermo-mechanical behavior of Cu-2.7vol.%Al2O3 alloy bar with high strength and electrical conductivity were investigated. The results show that the thermo-mechanical behavior of the alloy changes greatly with changing load direction or strain rate. For the same compression strain rate, the peak yield stress in the longitudinal compression is much higher than that of transverse compression. The homogeneous distribution of dynamic recrystallization grains or subgrains after longitudinal compression is much higher than that of transverse compression. For the longitudinal or transverse compression, the size of dynamical recrystallization grains decreases with increasing strain rate, the initial elongated bands can only be observed in the transverse compressions due to the effect of load direction. The flow stress oscillation phenomenon appears in both transverse and longitudinal compressions with a strain rate of 20 s(-1). Accordingly, the relationship between flow stress and microstructure, and a model of dynamic recrystallization in the transverse and longitudinal compressions, were established and analyzed in this paper.
10.1007-s11664-016-4605-3	-1		Cu-Sn phases are important intermetallic compounds formed at the interface between solder and substrate in the soldering process. They exist in several crystal structures (eta', eta, eta(1) and eta(2), etc.). The solid-state phase transformation that occurs among Cu-Sn intermetallic compounds is a crucial issue for industry applications, because the associated volume change inevitably leads to microstructural instability. Generally, four alloying elements, i.e., Ni, Au, Zn, and indium (In), are used as alloying elements to stabilize the high temperature hexagonal eta-phase. However, the physical mechanism of this stabilization effect, especially on the high temperature eta(1) and eta(2) phases, is still unclear. In the present study, first-principle calculations were performed to study the stability and mechanical properties of Cu5Sn4 (eta(1) and eta(2)) and Cu6Sn5 (eta') when doped with Ni, Au, Zn, and indium alloying elements. It is shown that their phase stability and mechanical properties could be enhanced by these elements in some circumstances. Ni-doping can significantly enhance both the stability and the mechanical properties of the three phases, whereas Zn-doping exhibits a significant effect on that of the eta(2) phase.
10.1007-s11664-016-4782-0	-1		Insufficient anti-welding properties limit the application of Cu-Cr contact material in vacuum switches with low contact pressure. The CuCr-W-C alloys that are prepared are for decreasing welding tendencies and keeping the voltage withstand by addition of W and C elements. It is found that the average welding force of CuCr-W-C alloys is reduced more than 50% compared with that of the Cu-50 Cr-50 alloy. Especially for CuCrW3.0C0.3 and CuCrW1.0C0.5, the welding forces reduce to only 10% of Cu50Cr50. Arc erosion areas of CuCr-W-C alloys are enlarged by five times more than that of the Cu50Cr50 alloy in the same arcing conditions. The results of type tests were qualified. The results suggested that the CuCrW2.0C1.0 alloy could be used in vacuum switches with low contact pressure to replace the W-Cu type contacts.
10.1007-s11664-016-4789-6	-1		Morphology of precipitates in the Cu-Cr-Ti alloys has been investigated using scanning electron microscope and transmission electron microscope in the present work. It has been found that there exist precipitates with two different morphology-spherical and cubic. Misfits between matrix and different precipitates have been determined using high resolution transmission electron microscope images. Interfacial energy and elastic strain energy have been calculated quantitatively. Tendency of morphology of precipitates has been explained by comparing the interfacial energy and elastic strain energy.
10.1007-s11664-017-5840-y	-1		Cu0.003Bi0.4Sb1.6Te3 alloys were prepared by using encapsulated melting and hot extrusion (HE). The hot-extruded specimens had the relative average density of 98%. The (00l) planes were preferentially oriented parallel to the extrusion direction, but the specimens showed low crystallographic anisotropy with low orientation factors. The specimens were hot-extruded at 698 K, and they showed excellent mechanical properties with a Vickers hardness of 76 HV and a bending strength of 59 MPa. However, as the HE temperature increased, the mechanical properties degraded due to grain growth . The hot-extruded specimens showed positive Seebeck coefficients, indicating that the specimens have p-type conduction. These specimens exhibited negative temperature dependences of electrical conductivity, and thus behaved as degenerate semiconductors. The Seebeck coefficient reached the maximum value at 373 K and then decreased with increasing temperature due to intrinsic conduction. Cu-doped specimens exhibited high power factors due to relatively higher electrical conductivities and Seebeck coefficients than those of undoped specimens. A thermal conductivity of 1.00 Wm(-1) K-1 was obtained at 373 K for Cu0.003Bi0.4Sb1.6Te3 hot-extruded at 723 K. A maximum dimensionless figure of merit, ZT(max) = 1.05, and an average dimensionless figure of merit, ZT(ave) = 0.98, were achieved at 373 K.
10.1007-s11664-017-5926-6	-1		We perform theoretical investigations on the structures of eta '-Cu6Sn5-based intermetallic compounds (IMCs) with different Co doping concentration (0-12.2 wt%) based on density functional theory (DFT). The variations of the structural, elastic and thermodynamic properties of (Cu, Co)(6)Sn-5 IMCs with pressure (0-18 GPa) and temperature (0-500 K) are obtained with the application of quasi-harmonic Debye model for the non-equilibrium Gibbs free energy. It is found that the volume of (Cu, Co)(6)Sn-5 shrinks with Co concentration increasing in the range of imposed pressure and temperature. At the same time, the bulk modulus of Cu4Co2Sn5 is the largest among those of Cu6Sn5, Cu5Co1Sn5 and Cu4Co2Sn5. By calculating the Debye temperature of Cu6Sn5, we find that it is higher than that of Cu5Co1Sn5 and Cu4Co2Sn5 when the pressure is higher than 2 GPa. Meanwhile, heat capacities of all three Cu6Sn5, Cu5Co1Sn5, and Cu4Co2Sn5 converge to a near-constant value at about 1090 J/mol K in the range of the imposed pressures.
10.1007-s11664-019-07570-3	-1		Tetrahedrites substituted with transition elements, Cu11TrSb4S13 (Tr=Mn, Fe, Co, Ni, Cu, and Zn), were synthesized by mechanically alloying and hot pressing, and their thermal stability, mechanical properties and thermoelectric performance, including phase transition (decomposition), elemental redistributions, microstructures, thermoelectric parameters, hardness, and bending strength, were examined. Hot-pressed compacts showed relative densities of 97.4-99.8%. As the atomic number of the transition element substituted for Cu-29 decreased (Ni-28, Co-27, Fe-26, and Mn-25), the lattice constant increased; however, the lattice constant also increased when Cu-29 was substituted with Zn-30 (higher atomic number). The electrical conductivity of tetrahedrites doped with transition elements decreased compared with that of intrinsic tetrahedrite Cu12Sb4S13. This was because transition elements were successfully substituted at Cu+ sites, and the carrier (hole) concentration decreased owing to electron donation. The Seebeck coefficient of Cu11TrSb4S13 was greater than that of Cu12Sb4S13, except for Cu11FeSb4S13. However, the thermal conductivity of the tetrahedrite decreased upon the substitution of transition elements owing to enhanced impurity phonon scattering. Endothermic reactions were observed at temperatures between 882 K and 984 K, which corresponded to each melting point, and the tetrahedrite melting point increased upon doping with transition elements. The Vickers hardness and three-point bending strength of Cu12Sb4S13 were 2.2 GPa and 23 MPa, respectively. However, the hardness (2.5-2.7 GPa) and bending strength (23-44 MPa) increased for Cu11TrSb4S13 as the result of the solid-solution hardening effect.
10.1007-s11664-020-07975-5	-1		Cu-0.25Se-0.25Te alloy has been melted in a vacuum induction furnace and then heat treated. Afterwards, equal-channel angular pressing (ECAP) and subsequent annealing were carried out on the obtained samples. The effects of the ECAP process and subsequent annealing on the microstructure and properties of the alloy have also been investigated by scanning electron microscopy, Vickers microhardness testing, and eddy-current conductivity measurements. The results suggest a morphological evolution of the grains during the ECAP process. The equiaxed grains of the heat-treated alloy initially developed into shapes elongated along the shearing plane, then a series of smaller streamlined strip-like grains appeared and were eventually crushed into fine and equiaxed grains with a size of about 5 mu m after different numbers of ECAP passes (one, two, four, or eight), along with a deformed strain epsilon. Furthermore, the microhardness (HV) rose sharply from 68 N/mm(2) to 140 N/mm(2) and then climbed steadily to 169 N/mm(2) under the comprehensive effect of epsilon and the refinement of deformed grains. By contrast, the electrical conductivity decreased slowly from 96.2% international annealing copper standard (IACS) to 93.5% IACS. The microhardness and the electrical conductivity of the samples were found to vary contrarily with the change of annealing temperature and stabilized at 500 degrees C. Notably, the electrical conductivity increased gradually, whereas the hardness of the alloys that were subject to a higher number of ECAP passes decreased remarkably with increasing annealing time at 300 degrees C.
10.1007-s11664-021-08992-8	-1		Cu-30 wt% Al mixtures produced by mechanical alloying were studied using x-ray diffractometry (XRD), field emission scanning electron microscopy (FESEM), and transmission electron microscopy (TEM). The results showed that the milling time affected the morphology and particle size, and the minimum particle size was 2.91 mu m for a moderate milling time of 4 h . The XRD results showed that a Cu(Al) solid solution was not detected in the Cu-rich Cu-Al mechanically-alloyed mixtures, but intermetallic compounds were formed under the conditions of this experiment. The theta-CuAl2 phase was formed during the early milling stage (2 h), but it disappeared, and only the gamma(1)-Cu9Al4 phase existed as the milling time continuously increased. In addition, the effect of thermally-assisted mechanisms on the formation of intermetallic compounds could be limited by controlling the temperature of the horizontal high-energy ball milling equipment. These observations indicate that the metastable gamma(1)-Cu9Al4 phase can exist stably due to non-thermally activated mechanisms. Moreover, the evolution of intermetallic compounds can be explained by the following process: as the ball milling progressed, intermetallics were formed in a layered structure and were then crushed to form fine particles that adhered to the large particles that were not completely broken.
10.1007-s11664-021-09144-8	6	grain; deformation; strain; strength; dislocation; cu-; tensile; size; ecap; grain size; sfe; ductility; hardening; high; stress	In this work, the commercial age-hardenable Cu-0.81Cr-0.07Zr alloy was solution heat treated at 930 degrees C and 1020 degrees C and processed at room temperature by 1 and 4 equal-channel angular pressing (ECAP) passes through routes A and B-C. Aging treatments were performed in the ECAPed and as-solubilized samples. The effects of processing and heat treatments on hardness and electrical conductivity were analyzed and correlated with microstructural evolution. It was found that during ECAP, grain refinement and dislocation hardening were the predominant hardening mechanisms. The electrical conductivity was mainly affected by the amount of solute in solid solution, being practically unaffected by the deformation caused by ECAP. It was observed that the precipitation kinetics were accelerated in the samples processed by ECAP, resulting in a decrease in the peak aging temperature. After 4 passes of ECAP followed by aging, the samples reached peak hardness of 193 HV and 201 HV for samples solubilized at 930 degrees C and 1020 degrees C, respectively. These values correspond to a 13% and 18% increase in hardness compared to commercial Cu-Cr-Zr alloys produced by a conventional solution heat treatment/cold working-aging route. Furthermore, the electrical conductivity remained above 70% IACS after ECAP-aging, which is still very attractive for electrical applications. Graphic Abstract
10.1007-s11664-022-09947-3	-1		Most conventional thermoelectric materials, such as semiconductors, are rigid and brittle, making it difficult for them to endure harsh working conditions, and causing high interfacial heat loss. Cupronickel (Cu-Ni)-based alloys are good candidates for thermoelectric application with outstanding mechanical properties. However, the low Seebeck coefficient and large thermal conductivity limit their performance to that of semiconductor thermoelectric materials. This work utilizes hot rolling deformation as a cost-effective method to improve the thermoelectric and mechanical properties of zinc-cupronickel (Cu-Ni-Zn). When the rolling reduction is increased from 0 to 70%, the Seebeck coefficient is improved by 12.1%, which can be attributed to the scattering of low-energy carriers at the grain boundaries. This sample obtains a 16.7% improvement in zT compared to the original counterpart. Besides thermoelectric properties, mechanical properties are also increased, especially the enhanced elongation by 300%, suggesting that hot rolling deformation holds great promise for engineering metals to produce thermoelectric devices with excellent mechanical properties.
10.1007-s11664-023-10381-2	-1		In this study, ternary and quaternary micro-alloyed copper (MAC) wires were formed by adding trace amounts of gold, palladium, and platinum to copper wires and introducing copper substrates to eliminate the influence of intermetallic compounds on the bonding surface. The reliability of the copper wires and copper substrates after wire bonding were investigated. The results show that the addition of platinum had no grain refinement effect, and the resistance was significantly increased compared to the addition of gold and palladium. However, the platinum-added MAC wire exhibited the best electrical fatigue life whether as a pure wire or bonding with the substrate. After bonding of the MAC wires with the copper substrates, they still retained certain mechanical properties and showed extremely good electrical fatigue characteristics. Overall, the Cu321 wire, with the addition of 0.3 wt% platinum, 0.2 wt% gold, and 0.1 wt% palladium, bonding with copper substrate exhibited the best reliability and can be applied in packaging industries.
10.1007-s11664-025-12319-2	-1		In this study, using a mechanical alloying process, various amounts of carbon nanotubes were distributed in the alloy using Cu30Ni70 particles as its novelty. The effects of the presence of carbon nanotubes in nanocomposites were investigated using energy analysis, four-point probe surface magnetometry (PSM), vibrating sample magnetometry (VSM), scanning electron microscopy (SEM), and x-ray diffraction (XRD) techniques to confirm the production of Cu-Ni/carbon nanotube (CNT) nanocomposites. Microstructural examination of the nanocomposites using 5 h XRD images showed that the Cu-Ni-Ni alloy was homogeneous. The results of strength testing (5 wt%) confirmed the effective role of nanotubes in the fineness of the structure. The finest structure was obtained at the highest percentage of reinforcement, confirming the uniform distribution of carbon nanotubes in the alloy matrix. The electrical CNTs showed that the increased electrical conductivity of the nanocomposites in the presence of additional carbon nanotubes in the substrate led to a decrease in the saturation magnetization and an increase in the repulsive force of the nanocomposites.
10.1007-s11665-007-9032-4	-1		The current available models describing superplastic deformation do not account for a number of important characteristics, leading to the current limited predictive capabilities of deformation and failure. In this work, the effects of cavitation and stress state on deformation stability during superplastic forming are investigated using Finite Element simulations. The simulations are performed using constant strain rate forming and using a proposed optimization approach based on a multiscale failure criterion that accounts for stress state, geometrical necking, and microstructural evolution including grain growth and cavitation. The simulations are conducted for the superplastic copper-based alloy Coronze-638 and the superplastic aluminum alloy Al-5083 which are known to develop significant cavitation during deformation. The results clearly show the importance of accounting for microstructural evolution during superplastic forming, especially when the state of stress is biaxial. Furthermore, the results highlight the effectiveness of the proposed optimization technique in reducing the forming time and maintaining the integrity of the formed parts.
10.1007-s11665-007-9071-x	-1		Recrystallization and precipitation behaviors after cold rolling and aging are investigated for Cu-0.7Cr-0.13Zr alloy. The processed alloy was characterized using the measurement of Vickers hardness, scanning electron microscopy, and transmission electron microscopy. The resultant complex microstructures are interpreted in terms of the interactions between precipitation and recrystallization. Upon aging at 500 degrees C for 1 h, the 45% rolled alloy exhibits a retarded recrystallization process and therefore an efficient hardening response, which are attributed to the pinning effect of fine dispersed precipitates on the dislocation. When heavily deformed and aged at high temperature, the alloy shows an accelerated process of recrystallization, and precipitates are found to coarsen.
10.1007-s11665-007-9082-7	6	grain; deformation; strain; strength; dislocation; cu-; tensile; size; ecap; grain size; sfe; ductility; hardening; high; stress	Precipitation strengthening of Cu-3Ti-1Cd alloy has been studied using hardness and tensile tests, electrical resistivity measurements, and transmission electron microscopy. The alloy exhibited a hardness of 117 HV in solution-treated (ST) condition and attained a peak hardness of 288 HV after aging at 450 degrees C for 72 h . Electrical conductivity increased from 7%IACS (International Annealed Copper Standard) in ST condition to 13%IACS on aging at 450 degrees C for 16 h . The alloy exhibited yield strength (YS) of 643 MPa and ultimate tensile strength (UTS) of 785 MPa in peak-aged (PA) condition. Strengthening in Cu-3Ti-1Cd alloy in PA condition is attributed to solid solution strengthening effect of cadmium (Cd) as well as fine scale precipitation of metastable and coherent beta'-Cu4Ti phase. On overaging at 450 or 500 degrees C, the alloy showed a decrease in hardness as a result of formation of equilibrium precipitate beta-Cu3Ti as continuous precipitation within the matrix and as discontinuous precipitation at the grain boundaries. While the tensile properties are better, the electrical conductivity of Cu-3Ti-1Cd alloy is less than that of binary Cu-2.7Ti alloy. The strengthening mechanism is the same in both binary and ternary alloys of Cu-Ti, i.e., precipitation of metastable and coherent beta'-Cu4Ti phase.
10.1007-s11665-007-9175-3	-1		The mechanical properties of six highly conductive copper alloys, GRCop-84, AMZIRC, GlidCop Al-15, Cu-1Cr-0.1Zr, Cu-0.9Cr, and NARloy-Z were compared. Tests were done on as-received hard drawn material, and after a heat treatment designed to simulate a brazing operation at 935 degrees C. In the as-received condition AMZIRC, GlidCop Al-15, Cu-1Cr-0.1Zr, and Cu-0.9Cr had excellent strengths at temperatures below 500 degrees C. However, the brazing heat treatment substantially decreased the mechanical properties of AMZIRC, Cu-1Cr-0.1Zr, Cu-0.9Cr, and NARloy-Z. The properties of GlidCop Al-15 and GRCop-84 were not significantly affected by the heat treatment. Thus there appear to be advantages to GRCop-84 over AMZIRC, Cu-1Cr-0.1Zr, Cu-0.9Cr, and NARloy-Z if use or processing temperatures greater than 500 degrees C are expected. Ductility was the lowest in GlidCop Al-15 and Cu-0.9Cr; reduction in area was particularly low in GlidCop Al-15 above 500 degrees C, and as-received Cu-0.9Cr was brittle between 500 and 650 degrees C. Tensile creep tests were done at 500 and 650 degrees C; the creep properties of GRCop-84 were superior to those of brazed AMZIRC, Cu-1Cr-0.1Zr, Cu-0.9Cr, and NARloy-Z. In the brazed condition, GRCop-84 was superior to the other alloys due to its greater strength and creep resistance (compared to AMZIRC, Cu-1Cr-0.1Zr, Cu-0.9Cr, and NARloy-Z) and ductility (compared to GlidCop Al-15).
10.1007-s11665-008-9336-z	-1		The effect of copper, phosphorus, and chromium present in a semikilled reinforcing bar steel produced by in-line quenching [thermomechanical treatment (TMT)] process on the tensile properties, microstructure, and corrosion resistance of steel in simulated chloride environment has been investigated. The results have been compared with that of a semikilled C-Mn reinforcing bar steel without these alloying elements produced by the same process route. Though the amount of phosphorus (0.11 wt%) was higher than that specified by ASTM A 706 standard, the Cu-P-Cr steel exhibited a composite microstructure, and good balance of yield stress, tensile stress, elongation, and ultimate tensile to yield stress ratio. Two conventional test methods, namely, the salt fog, and potentiodynamic polarization tests, were used for the corrosion test. The rust formed on Cu-P-Cr steel was adherent, and was of multiple colors, while the corrosion products formed on the C-Mn steel were weakly adherent and relatively darker blue. Also, the free corrosion potential of the Cu-P-Cr steel was nobler, and the corrosion current was markedly lower than that of a C-Mn rebar. The Cu-P-Cr steel did not develop any pits/deep grooves on its surface even after the prolonged exposure to salt fog. The improved corrosion resistance of the Cu-P-Cr steel has been attributed to the presence of copper, phosphorus, and small amount of chromium in the dense, adherent rust layer on the surface of reinforcing steel bar. A schematic mechanism of charge transfer has been proposed to explain the improved corrosion resistance of the Cu-P-Cr alloyed TMT rebar.
10.1007-s11665-009-9397-7	4	transformation; martensite; martensitic; phase; shape; beta; memory; shape memory; temperature; temperatures; martensitic transformation; gamma; transformation temperatures; effect; thermal	Cu-13.4Al-5Ni alloy single crystals were investigated after performing the corresponding heat treatments to reveal the formation of equilibrium alpha and gamma(2) phases and to examine transformation processes occurring in the alloy during heating-cooling cycles between room temperature and 970 K. Transformation processes were examined using heat flux DSC, structure examinations were performed using optical microscope and SEM devices, and phase identifications were carried out by XRD method. Identification of the equilibrium alpha phase using XRD method was not possible on the single crystal samples. According to the results, the equilibrium phases (alpha and gamma(2)) form only after long-term heat treatments. Because of that, aging processes do not affect the thermoelastic martensitic transformation of the CuAlNi alloy. This phenomenon is probably caused by the high Ni content that decreases the diffusion rate in CuAlNi alloys.
10.1007-s11665-009-9398-6	-1		Foams and other highly porous materials with a cellular structure are known to have many interesting combinations of physical and mechanical properties. In addition, foaming of shape memory alloys (SMA) greatly improves the set of application possibilities. In this work an open-cell metal foam of a CuZnAl SMA is presented. This foam was produced through a recently proposed process, which consists mainly in molten metal infiltration of a bed of silica-gel particles and the subsequent use of hydrofluoric acid (HF) as solvent. The results showed that very regular open-cell foams could be obtained, having an almost spherical cell morphology and relative densities of approximately 0.3. Microstructural and compositional analyses on foamed specimens showed uniform microstructure of ligaments and the absence of SiO(2) interaction with the metal. In this way the possibility of foaming CuZnAl system through the proposed low-cost process was clearly demonstrated.
10.1007-s11665-010-9700-7	-1		By means of pulse electrodeposition technique, a nanocrystalline Cu-0.42at%Bi alloy with a grain size down to similar to 10 nm was synthesized. The thermal stability of Cu-Bi electrodeposit was investigated using differential scanning calorimetry (DSC), x-ray diffraction (XRD), transmission electron microscopy (TEM), and hardness measurements. The temperature at which this material tends to become unstable was found to be 160 A degrees C. DSC revealed an exothermal peak between 190 and 300 A degrees C, caused by grain growth . It was observed that segregation of Bi at grain boundary has a considerable effect on the thermal stability of the Cu-Bi alloy. Tensile test showed the sample interestingly possesses a high strength of 760 MPa, while no plastic strain is detected.
10.1007-s11665-011-0084-0	-1		The microstructure and properties of a hot rolled-quenched Cu-Cr-Zr-Mg-Si alloy were investigated by transmission electron microscopy observations, micro-hardness and tensile strength testing, and electrical conductivity measurement. The results show that the hot rolling-quenching (HR-Q) process and subsequent thermomechanical treatments are successfully developed to manufacture Cu-Cr-Zr-Mg-Si alloy strips. Solution treatment can be finished during the HR-Q process, and good combinations of strength, conductivity, and softening resistance are obtained for the thermomechanically treated strips. Ordered fcc structure precipitates which exhibit a cube-on-cube orientation relationship with the matrix are responsible for the improvements of properties. The properties of hot rolled-quenched Cu-Cr-Zr-Mg-Si alloy strips can be further improved by two-step rolling and aging process. The improvements of properties are attributed to the interactions of precipitation strengthening and strain hardening.
10.1007-s11665-012-0198-z	-1		A novel metal matrix composite (MMC), Cu-Cr-MWCNT (copper-chromium-multiwalled carbon nanotube), was manufactured using a powder metallurgy technique. Cu-Cr alloy is widely adopted for contacts in vacuum circuit breakers. MWCNT was incorporated in an effort to enhance electrical conductivity and decrease the usage of Cr as strategic metal. Optimized milling conditions and sintering profiles were utilized to minimize any significant damage to the MWCNTs but yet provide homogeneous distribution of all constituents. Raman spectroscopy, transmission electron microscopy (TEM), and scanning electron microscopy (SEM) were used to determine the crystal structure orientation, microstructure, and morphology, respectively, of the composite. Raman peak shift and intensity ratios assessed the stresses induced and the degree of disorder of MWCNTs in the composite. TEM indicated carbide and oxide formations in the composite. SEM images revealed the presence of MWCNTs within the metal matrix. The corrosion resistances of the composite with and without MWCNTs was determined by cyclic potentiodynamic polarization (ASTM F 2129-08) in phosphate buffer saline solution at 37 A degrees C.
10.1007-s11665-013-0482-6	-1		A high-strength Cu-Ni-Si alloy was developed with the additions of Co and Zr. The aging curve for the alloy was generated using hardness. Electron microscopy studies were conducted to analyze the phases in the alloy. Two types of phases, one of copper matrix and the other of Ni-Si-Co-Zr intermetallic phase, could be identified using scanning electron microscopy. Transmission electron microscopy studies confirmed the presence of two types of precipitates in solution-treated and aged (STA) condition, i.e., Ni2Si and Co2Si. Mechanical properties and electrical conductivity were evaluated in solution-treated (ST) and STA conditions. Aging of the ST samples at 500 A degrees C for 3 h has shown an increase of 72 and 15% in yield strength (YS) and electrical conductivity, respectively. This increase in YS and conductivity on aging is primarily attributed to the formation of fine Ni2Si and Co2Si precipitates.
10.1007-s11665-013-0763-0	2	corrosion; surface; film; electrochemical; films; spectroscopy; layer; current; solution; potential; resistance; composition; x-ray; ions; showed	The present investigation concerns electroless Ni-P coatings prepared onto the copper-nickel alloy (CuNi 90/10) to enhance the erosion-corrosion resistance. X-ray diffraction technique (XRD), scanning electron microscopy, and electrochemical methods were utilized to study the heat treatment effects on the erosion-corrosion resistance and the physical properties of the coatings. The results indicated that both the as-plated and coating with post-heat treatment (PHT) showed much higher self-passivation ability and much lower current densities than that of the copper-nickel alloy (CuNi 90/10). XRD results showed that both the as-plated and coating with PHT had amorphous structure and the effect of PHT at 190 A degrees C on the structure of Ni-P coating was not significant. Compared with coating with PHT, the as-plated exhibited lower erosion-corrosion resistance due to some small pits and cracks. The coating with PHT demonstrated significant improvement of erosion-corrosion resistance in 3.5 wt% NaCl solution, which was attributed to better protective film, lower porosity of coatings, and high micro-hardness compared with Ni-P coating without PHT.
10.1007-s11665-013-0765-y	-1		In this paper, two Indium-alloyed Cu-based bulk metallic glasses, Cu54Zr37Ti8In1 and Cu50Zr37Ti8In5, have been evaluated with nanoindentation testing. Both bulk metallic glasses have homogenous nature in structure. Both hardness and Young's modulus of bulk metallic glasses do not show a loading rate-dependent. Addition of In decreases hardness and Young's modulus, but increases creep-resistance of bulk metallic glasses. Indentation creep of two bulk metallic glasses has also been investigated. The displacement-time curves of creep processes were described with generalized Kelvin model. The creep displacement, compliance spectrum, and retardation spectrum for each bulk metallic glass were discussed comparatively. The results showed that Cu50Zr37Ti8In5 has better creep-resistance at room temperature and a more relaxed state.
10.1007-s11665-014-0882-2	-1		In this investigation, the effect of different degree of cold rolling and post-aging treatment on the microstructure and mechanical properties of a Cu-3wt%Ag-0.5wt%Zr alloy was studied by means of hardness measurement, tensile tests, optical and electron microscopy. The alloy was subjected to cold rolling up to 80% followed by aging in the temperature range of 400-500 A degrees C. The yield strength, ultimate tensile strength and hardness were found to increase as degree of cold rolling increased, but at the expense of ductility. Aging of cold rolled samples in the studied temperature range has resulted in different combinations of strength and ductility. However, aging of cold rolled samples at 400 A degrees C for 1 h has resulted in a combination of high strength and moderate ductility. A yield strength and ultimate tensile strength of 511 and 560 MPa, respectively with a ductility of 12% were achieved for 80% cold rolled and aged (400 A degrees C for 1 h) sample. The high strength achieved after 80% cold rolling and aging is mainly attributed to precipitation of fine silver precipitates.
10.1007-s11665-014-0926-7	-1		Effects of small addition of Zr on the microstructures and properties of as-cast Cu50Ag46-xZrxTi4 alloys were investigated by differential scanning calorimeter (DSC), x-ray diffraction, microscope, and property testings. The results show that the melting point of the Cu50Ag46Ti4 alloys does not change obviously with the addition of Zr at the melting points of about 779 A degrees C. Adding Zr reduces the volume fraction and size of the board strips of Cu3Ti phase, promotes the uniform distribution of the new phase Cu4AgZr, and improves the Vickers hardness and shear strength of the based alloys. Moreover, increasing the Zr content can improve the high-temperature oxidation resistance of alloys.
10.1007-s11665-014-1228-9	-1		Accumulative roll bonding is a severe plastic deformation process used for Cu-Al-Mn shape memory alloy. The main purpose of this study is to investigate the possibility of grain refinement of Cu-9.5Al-8.2Mn (in wt%) shape memory alloy using accumulative roll bonding and post-deformation annealing. The alloy was successfully subjected to 5 passes of accumulative roll bonding at 600 A degrees C. The microstructure, properties as well as post-deformation annealing of this alloy were investigated by optical microscopy, scanning electron microscopy, x-ray diffraction, differential scanning calorimeter, and bend and tensile testing. The results showed that after 5 passes of ARB at 600 A degrees C, specimens possessed alpha A + beta microstructure with the refined grains, but martensite phases and consequently shape memory effect completely disappeared. Post-deformation annealing was carried out at 700 A degrees C, and the martensite phase with the smallest grain size (less than 40 mu m) was obtained after 150 s of annealing at 700 A degrees C. It was found that after 5 passes of ARB and post-deformation annealing, the stability of SME during thermal cycling improved. Also, tensile properties of alloys significantly improved after post-deformation annealing.
10.1007-s11665-014-1352-6	15	aging; strength; conductivity; electrical conductivity; electrical; mpa; treatment; strengthening; degrees; cu-; cold; precipitation; tensile strength; tensile; iacs	A Cu-0.7Fe-0.15P (wt%) alloy was designed, and its comprehensive properties, especially electrical conductivity and temper-softening resistance of the designed alloy, were higher than those of traditional Cu-Fe-P alloys. The microstructure of this alloy was investigated with optical microscopy, scanning electron microscopy, and transmission electron microscopy. The particle of secondary phase was confirmed to be Fe2P with x-ray spectroscopy and digital diffractogram. By virtue of precipitation hardening and work hardening, the tensile strength and electrical conductivity of Cu-0.7Fe-0.15P alloy were 498 MPa and 62% IACS, respectively. The electrical conductivity of this alloy can be up to 92% IACS due to the complete precipitation of Fe2P. After repeating the cold rolling and aging process for three times, the tensile strength, elongation, and conductivity of this alloy were 467 MPa, 22%, and 78% IACS, respectively. Due to the low driving force of recrystallization and the pinning effect of fine dispersed Fe2P, the alloy with low deformation rate showed excellent softening resistance. The designed alloy can be used as a high-strength, high-electrical-conductivity lead-frame alloy.
10.1007-s11665-015-1436-y	4	transformation; martensite; martensitic; phase; shape; beta; memory; shape memory; temperature; temperatures; martensitic transformation; gamma; transformation temperatures; effect; thermal	This paper presents the investigation on the effects of various thermal treatments and quenching media on the phase transformation behaviour of Cu-Al-Ni-Co shape memory alloys (SMAs). The transformation temperatures were determined using a differential scanning calorimeter. The variation of cooling rates had a consequential effect on the phase transformation characteristics of the Cu-Al-Ni-Co SMAs. Nevertheless, the transformation temperature peaks were varied in terms of location as well as heat flow. The results indicated that there was an improvement in transformation temperatures whenever ice water was used as quenching medium. It was also observed that the forward transformation temperatures were higher than the reverse transformation. It was verified that the required heat for the transformation of martensite into austenite was more than the transformation of austenite into martensite. Moreover, thermodynamic parameters, such as enthalpy and entropy, tended to decrease and increase as a result of the changes in the cooling rates of each medium. To clarify the variations of the structures and properties of Cu-Al-Ni-Co SMA quenched samples, x-ray diffraction, atomic force microscopy, field emission scanning electron microscopy, energy dispersive spectroscopy, and Vickers hardness were used.
10.1007-s11665-015-1483-4	-1		The effect of Sn addition and heat treatment on the microstructure and properties of Cu-3Ti and Cu-2Ti alloys was studied. The microstructure and phase constituents were characterized by an optical microscope, x-ray diffractometer, and transmission electron microscope, and the electrical conductivity and hardness were determined as well. The results show that the as-cast microstructure of Cu-Ti-Sn alloys consists of alpha-Cu(Ti,Sn) and primary CuSn3Ti5 intermetallic compound. CuSn3Ti5 phase has a hexagonal structure with the lattice parameters a = 0.81737 nm, b = 0.81737 nm, and c = 0.55773 nm. With the increase of aging time, the electrical conductivity progressively increases, while the hardness increases and then decreases. After aging at 450 A degrees C for 8 h, Cu-3Ti-2Sn alloy has an electrical conductivity of 23.1 MS/m and a hardness of 134.5 HV, and the electrical conductivity and hardness of Cu-2Ti-2Sn alloy are 21.5 MS/m and 119.3 HV, respectively. An appropriate aging is beneficial for the precipitation of coherent metastable beta'-Cu4Ti phase, which can strengthen Cu-3Ti-2Sn and Cu-2Ti-2Sn alloys. However, a prolonged aging time results in the decrease of hardness due to the formation of incoherent equilibrium beta-Cu3Ti phase. The presence of CuSn3Ti5 phase reduces the solute Ti content in the copper matrix and, thus, gives rise to the increase of the electrical conductivity of Cu-Ti-Sn alloys.
10.1007-s11665-015-1516-z	6	grain; deformation; strain; strength; dislocation; cu-; tensile; size; ecap; grain size; sfe; ductility; hardening; high; stress	In the present investigation, mechanical properties and microstructure of the Cu-Cr-Zr-Ti alloy were characterized by tensile testing, hardness measurement, and transmission electron microscopy (TEM) in different heat treatment conditions. TEM studies confirmed the presence of four phases in the solution-treated condition namely: copper matrix, spherical chromium-rich, TiS2, and ZrS2 particles. Aging in the temperature range of 400-600 degrees C has led to significant change in strength . Samples aged at 500 degrees C for 2 h showed maximum ultimate tensile strength and yield strength of 330 and 212 MPa, respectively, with ductility of 23%. The phase responsible for high strength after aging at 500 degrees C was identified as fine bcc chromium precipitates with average size of 3.0 perpendicular to 1.0 nm.
10.1007-s11665-015-1595-x	-1		The effects of small amount addition of the rare-earth Ce on the microstructure, mechanical properties, and corrosion resistance behavior of cast pure copper were investigated using optical microscopy, scanning electron microscopy, energy-dispersive x-ray spectrometry (EDS), transmission electron microscopy (TEM), tensile testing, and potentiodynamic polarization measurements. It was indicated that Ce addition significantly refined the grain and enhanced the tensile strength of cast pure copper. Copper alloy with 0.12 wt% Ce addition had the smallest equiaxed grains of 358. +/- A 23.53 mu m and the ultimate tensile strength of 181.7 +/- A 3.7 MPa. Ce formed spherical second phase particles with copper, which were revealed as Cu6Ce by EDS and TEM results. Solid solution strengthening, fine-grain strengthening, and second-phase precipitation strengthening played important roles in the tensile strength improvement. However, the elongation decreased due to the second phase particles' inhomogeneous distribution. The corrosion resistance properties of micro-alloyed copper alloys in 0.5 mol/L HCl solution were improved when Ce addition was limited to less than 0.069 wt% owing to a purification effect and the formation of a compact corrosion product film on the copper matrix. The influencing mechanisms of Ce on the microstructure, mechanical property, and corrosion property were also discussed in detail.
10.1007-s11665-015-1693-9	8	hot; deformation; strain; strain rate; dynamic; hot deformation; recrystallization; dynamic recrystallization; flow; rate; flow stress; compression; constitutive; degrees; stress	Hot deformation behavior of the Cu-Cr-Zr and Cu-Cr-Zr-Ce alloys was investigated by compressive tests using the Glee-ble-1500D thermomechanical simulator at 650-850 A degrees C and 0.001-10 s(-1) strain rate. The flow stress decreased with the deformation temperature at a given stain rate. However, the flow stress increased with the strain rate at the same deformation temperature. The constitutive equations for two kinds of alloys were obtained by correlating the flow stress, the strain rate and temperature using stepwise regression analysis. The addition of Ce can refine the grain and effectively accelerate dynamic recrystallization. The processing maps were established, based on the dynamic material model. Instability zones in the flow behavior can be easily recognized. Hot deformation optimal processing parameters were obtained in the range of this experiment. The hot deformation characteristics and microstructure were also analyzed by the processing maps. The addition of Ce can optimize hot workability of the Cu-Cr-Zr alloy.
10.1007-s11665-015-1706-8	-1		The evolution of micro-texture below the machined surface is computationally modeled and experimentally verified. The orientation distribution functions of the grains below the surface were represented in spectral form. The microstructure descriptor coefficients were derived, and their change with respect to the change in the cutting feed rate was computationally calculated and monitored. Micro-texture experimental observations conducted by electron back-scatter diffraction technique verify the modeling outputs. Continuation of changing the process parameter was done by finite element method, and the evolution in texture was investigated by computational modeling. The process path function which correlates micro-texture evolution and cutting feed rate, was obtained by applying the principle of orientation conservation in the Euler space. As a result of the major finding of this work, i.e., derivation of process path functions, the evolution of texture as a function of the material feed rate is numerically determined without any need to texture modeling or finite element analyses.
10.1007-s11665-015-1778-5	-1		In the present study, dynamic elastic constants namely Young's modulus, shear modulus, Poisson's ratio, and internal friction properties for polycrystalline Cu-0.68Cr-0.04Zr-0.03Ti-0.015Fe (wt%) alloy have been evaluated from 25 to 650 A degrees C temperature in argon environment. These properties were determined using resonance-based high-temperature impulse excitation technique. The temperature-dependent elastic constants are very vital for the thermo-structural analysis to predict the performance of the component/structure. The test results revealed that, the alloy exhibits linear reduction in Young's modulus and shear modulus with increasing temperature. On the other hand, the calculated Poisson's ratio showed minor increase with temperature. It was shown that, the variation in the internal friction is attributed to in situ aging in the temperature range studied. Overaging beyond 500 A degrees C has led to drastic increase of internal friction. This has been supported by hardness measurement, tensile test, differential scanning calorimetry test, and transmission electron microscopy examination.
10.1007-s11665-015-1790-9	-1		In this study, the effects of electron beam welding on the microstructure, microhardness, and electrical conductivity of precipitation-hardened Cu-0.804%Cr-0.063%Zr (wt%) alloy plates were investigated. Experiments were carried out following a central composite design of experiments. Five welding schedules yielding the higher hardness were chosen and then were subjected to standard metallographic and various microscopy techniques to reveal the type, morphology, and distribution of the precipitates and to obtain the sub-structural information from the weld zone. X-ray diffraction studies revealed predominant formation of intermetallic phases in the welded zones of some of the samples, which could have resulted in higher hardness and better electrical conductivity compared to those of other ones. Microhardness values in the fusion zone and heat-affected zone were found to be less than that of the parent material. The mechanism of damage in Cu-Cr-Zr plates due to welding was also explained.
10.1007-s11665-015-1832-3	-1		This investigation reports the effect of thermal shock of different gradients, i.e., immediate transition from high temperature to cryogenic environment and vice versa on the flexural properties of Al2O3 particulate reinforced Cu metal matrix micro-and nano-composites fabricated by powder metallurgy route. The specimens were also thermally conditioned at high as well as sub-zero temperatures separately. The specimens were subjected to 3-point flexural test followed by fractography, and the fracture micro-characteristics were studied under field emission scanning electron microscopy and transmission electron microscopy to predict the dislocation behavior under induced thermal stresses and mismatch . The degree of improvement in flexural strength is higher for the composites experiencing lower degree of thermal shock, i.e., improvement in flexural strength is higher for a thermal shock of 80 degrees C than for 160 degrees C temperature gradients. Particle pull-out, crack entrapment, and physical outgripping of alumina particles act as the operative mechanisms during fracture of thermally shocked composites.
10.1007-s11665-015-1851-0	5	materials; thermal; heat; properties; material; welding; sintering; fusion; strength; laser; heat sink; thermal conductivity; mechanical; sink; manufacturing	Combination of extreme service conditions and complex thermomechanical loadings, e.g., in electronics or power industry, requires using advanced materials with unique properties. Dissipation of heat generated during the operation of high-power electronic elements is crucial from the point of view of their efficiency. Good cooling conditions can be guaranteed, for instance, with materials of very high thermal conductivity and low thermal expansion coefficient, and by designing the heat dissipation system in an accurate manner. Conventional materials such as silver, copper, or their alloys, often fail to meet such severe requirements. This paper discusses the results of investigations connected with Cu-C (multiwall carbon nanotubes (MWNTs), graphene nanopowder (GNP), or thermally reduced graphene oxide (RGO)) composites, produced using the spark plasma sintering technique. The obtained composites are characterized by uniform distribution of a carbon phase and high relative density. Compared with pure copper, developed materials are characterized by similar thermal conductivity and much lower values of thermal expansion coefficient. The most promising materials to use as heat dissipation elements seems to be copper-based composites reinforced by carbon nanotubes (CNTs) and GNP.
10.1007-s11665-016-1918-6	-1		The effects of B and Ce on the corrosion resistance of Cu-0.22Fe-0.06P alloy were investigated by salt spray and electrochemical tests. The corrosion morphology was studied by scanning electron microscopy. The corrosion products were characterized by energy-dispersive x-ray spectroscopy and x-ray diffraction analysis. The impurity content was determined by inductively coupled plasma mass spectrometry. The conductivity was measured using an eddy current conductivity meter. The grains of Cu-0.22Fe-0.06P alloy were refined by the addition of B and Ce. The electrochemical corrosion process of alloy is retarded due to purification effect of B and Ce. After the addition of a trace amount of B, the corrosion resistance of the alloy decreased. The corrosion resistance of Cu-0.22Fe-0.06P-0.025B-0.05Ce was better than that of Cu-0.22Fe-0.06P-0.025B due to the fact that the purification effect of Ce is better than that of B. The main corrosion products of the Cu-Fe-P alloys in a NaCl solution are Cu2Cl(OH)(3) and Cu2O. The addition of trace amounts of B and Ce did not change the components of the corrosion product.
10.1007-s11665-016-1937-3	8	hot; deformation; strain; strain rate; dynamic; hot deformation; recrystallization; dynamic recrystallization; flow; rate; flow stress; compression; constitutive; degrees; stress	The hot deformation behavior of the Cu-Cr-Zr-Ag alloy has been investigated by hot compressive tests in the 650-950 A degrees C temperature and 0.001-10 s(-1) strain rate ranges using Gleeble-1500D thermo-mechanical simulator. The microstructure evolution of the alloy during deformation was characterized using optical and transmission electron microscopy. The flow stress decreases with the deformation temperature and increases with the strain rate. The apparent activation energy for hot deformation of the alloy was 343.23 kJ/mol. The constitutive equation of the alloy based on the hyperbolic-sine equation was established to characterize the flow stress as a function of the strain rate and the deformation temperature. The processing maps were established based on the dynamic material model. The optimal processing parameters for hot deformation of the Cu-Cr-Zr-Ag alloy are 900-950 A degrees C and 0.001-0.1 s(-1) strain rate. The evolution of DRX microstructure strongly depends on the deformation temperature and the strain rate.
10.1007-s11665-016-1981-z	4	transformation; martensite; martensitic; phase; shape; beta; memory; shape memory; temperature; temperatures; martensitic transformation; gamma; transformation temperatures; effect; thermal	This paper describes the effects of precipitation of alpha-phase on a Cu-Al-Ni shape memory alloy (SMA) with chemical composition bordering on beta region. By differential scanning calorimetry, a series of reproducible heat flow fluctuations was determined on heating a hot-rolled martensitic Cu-Al-Ni SMA, which was associated with the precipitation of alpha-phase. Two heat treatments were given to the SMA so as to freeze its states before and after the thermal range for precipitation, respectively. The corresponding microstructures of the two heat-treated states were observed by optical and scanning electron microscopy and were compared with the initial martensitic state. Energy dispersive spectroscopy experiments were carried out to determine the chemical compositions of the different phases formed in heat-treated specimens. The initial as well as the heat-treated specimens with a lamellar shape were further comparatively investigated by dynamic mechanical analysis and two-way shape memory effect (TWSME) tests comprising heating-cooling cycles under a bending load. Temperature scans were applied to the three types of specimens (initial and heat-treated states), so as to bring out the effects of heat treatment. The storage modulus increased, corresponding to the reversion of thermoelastic martensite and disappeared with the formation of precipitates. These features are finally discussed in association with TWSME under bending.
10.1007-s11665-016-1987-6	15	aging; strength; conductivity; electrical conductivity; electrical; mpa; treatment; strengthening; degrees; cu-; cold; precipitation; tensile strength; tensile; iacs	Microstructure of the Cu-Ni-Si-P alloy was investigated by transmission electron microscopy (TEM). The alloy had 551 MPa tensile strength, 226 HV hardness, and 36% IACS electrical conductivity after 80% cold rolling and aging at 450 A degrees C for 2 h . Under the same aging conditions, but without the cold rolling, the strength, hardness, and electrical conductivity were 379 MPa, 216 HV, and 32% IACS, respectively. The precipitates identified by TEM characterization were delta-Ni2Si. Some semi-coherent spherical precipitates with a typical coffee bean contrast were found after aging for 48 h at 450 A degrees C. The average diameter of the observed semi-coherent precipitates is about 5 nm. The morphology of the fracture surface was observed by scanning electron microscopy. All samples showed typical ductile fracture. The addition of P refined the grain size and increased the nucleation rate of the precipitates. The precipitated phase coarsening was inhibited by the small additions of P. After aging, the Cu-Ni-Si-P alloy can gain excellent mechanical properties with 804 MPa strength and 49% IACS conductivity. This study aimed to optimize processing conditions of the Cu-Ni-Si-P alloys.
10.1007-s11665-016-2147-8	-1		Microstructure evolution and hardness changes of an ultra-high strength Cu-Ni-Si alloy during thermo-mechanical processing have been investigated. For hot-compressive deformation specimens, dynamic recrystallization preferentially appeared on deformation bands. As deformation temperature increased from 750 to 900 A degrees C, elongated grains with the Cubic texture {001} aOE (c) 100 > were substituted by recrystallized grains with Copper texture {112} aOE (c) 111 >. For the samples having undergone cold rolling followed by annealing, static recrystallization preferentially occurred in the deformation bands, and then complete recrystallization occurred. Goss, Cubic, and Brass textures remained after annealing at 600 and 700 A degrees C for 1 h; R texture {111} aOE (c) 211 > and recrystallization texture {001} aOE (c) 100 > were formed in samples annealed at 800 and 900 A degrees C for 1 h, respectively. For samples processed under multi-directional forging at cryogenic temperature, the hardness was increased as a result of work hardening and grain refinement strengthening. These were attributed to the formation of equiaxed sub-grain structures and a high dislocation density.
10.1007-s11665-016-2267-1	-1		The evolution of microstructure in the Cu-0.5%Cr-0.2%Zr alloy subjected to thermomechanical treatment has been studied by means of the x-ray analysis. The workpieces have been subjected to 1, 2, 4 and 8 passes of equal channel angular pressing, plain cold rolling and aging treatment. The results of the XRD investigations reflect the evolution of the lattice parameter, the size of coherently scattering domains, the elastic microdistortions and the dislocation density in Cu matrix. The observed changes in the microstructure are explained by the competition between the developing defects and precipitation of the Cr phase particles from the Cu matrix.
10.1007-s11665-016-2354-3	15	aging; strength; conductivity; electrical conductivity; electrical; mpa; treatment; strengthening; degrees; cu-; cold; precipitation; tensile strength; tensile; iacs	A novel Cu-10Zn-1.5Ni-0.34Si alloy was designed to replace the expensive tin-phosphor bronze in this paper. The alloy had better comprehensive mechanical properties than traditional C5191 alloy. The aged Cu-10Zn-1.5Ni-0.34Si alloy had a hardness of 220 HV, electrical conductivity of 28.5% IACS, tensile strength of 650 MPa, yield strength of 575 MPa and elongation of 13%. Ni2Si precipitates formed during aging, and the crystal orientation relationship between matrix and precipitates was: (001)(alpha)//(001)(delta), and [110](alpha)//[100](delta). Ductile fracture surface with deep cavities was found in the alloy. Solid solution strengthening, deformation strengthening and precipitation strengthening were found to be core strengthening mechanisms in the alloy.
10.1007-s11665-016-2419-3	-1		A combination of high strength and good ductility was achieved in a precipitation hardenable Cu-3Ag-0.5Zr alloy through cryo-rolling (80% reduction in thickness) and aging in the temperature range (200-500 A degrees C). The high-strength sheets produced by cryo-rolling showed a threefold increase in yield strength compared to that of the solution-treated and aged (220 MPa) sample, while retaining good ductility. An optimum combination of high strength (614 MPa) and ductility (8%) was achieved by 80% cryo-rolling and aging at 320 A degrees C for 1 h . The high strength and good ductility obtained was attributed to various microstructural factors such as deformation twins, ultra-fine grains, high dislocation density and fine nano-sized silver precipitates.
10.1007-s11665-017-2701-z	8	hot; deformation; strain; strain rate; dynamic; hot deformation; recrystallization; dynamic recrystallization; flow; rate; flow stress; compression; constitutive; degrees; stress	Based on compression tests in the temperature range of 800-950 A degrees C and the strain rate range of 0.001-20 s(-1) on a Gleeble-3500 thermomechanical simulator, the dynamic recrystallization (DRX) kinetics of Cu-0.36Cr-0.03Zr alloy is developed by further analysis of true stress-strain curves and by investigating microstructures under different deformation conditions. The kinetics of dynamic recrystallization is expressed as the modified JMAK model, and effects of varying strain rate and temperature on the model parameters, including the critical strain, peak strain and materials constant k (d) , are investigated. The complete DRX grain size is described as a power law function of Zener-Hollomon parameter (Z), and it agrees well with the experimental data.
10.1007-s11665-017-2738-z	-1		In the present paper, the aging precipitation and coarsening of disk-like delta-Ni2Si particles in Cu and Cu-10Zn alloys aged at 450 degrees C have been investigated by hardness, electric resistivity measurement and transmission electron microscopy observation. The coarsening dynamics of the average diameter of the delta-Ni2Si particles coincides with the t(1/3) time law for both alloys. The coarsening of the diminution of supersaturation related to aging time t coincides with the t(-1/3) time rule. Adding Zn to the Cu-Ni-Si alloy increases the growth and coarsening rate of the particles mainly because of the increased diffusivity D of the delta-Ni2Si particles in the matrix. The value of D of the delta-Ni2Si particles in the Cu-xZn (x = 0, 10 wt%) matrix and the Cu/delta-Ni2Si interfacial energy gamma are independently calculated by using the Lifshitz-Slyozov-Wagner theory which was extended to include disk-like particles by Boyd and Nicholson. The values of D and gamma increase from 0.77 x 10(-19) to 2.21 x 10(-19) m(2)/s and 0.19 to 0.63 J/m(2), respectively, when Zn is added to the Cu-Ni-Si alloy. These calculations and the analysis show that the properties of Cu-Ni-Si-Zn alloy can significantly be enhanced by reducing the aging temperature.
10.1007-s11665-017-3003-1	-1		Molecular dynamics (MD) simulation-based studies of tensile test and structural evolution of Cu-5 at% Zr alloy under asymmetric cyclic loading (i.e., ratcheting behavior) considering various stress ratios such as 2 0.2,-0.4 and-0.6 for different temperatures, viz.approximate to 100, 300 and 500 K have been performed using embedded atom model Finnis-Sinclair potential. According to obtained stress-strain response from MD calculation, Cu-5 at% Zr alloy specimen is pristine in nature as sudden drop in stress just after yield stress and subsequent elastic type deformation are observed for this alloy. Predicted ratcheting strain by MD simulation for Cu-5 at% Zr alloy varies from 4.5 to 5%. Significant increase in ratcheting strain has been observed with the increase in temperature. Slight reduction in crystallinity is identified at the middle of the each loading cycle from the performed radial distribution function analysis and cluster analysis.
10.1007-s11665-017-3010-2	16	wear; composite; composites; powders; milling; particles; powder; wt; sliding; friction; hardness; matrix; mechanical; surface; properties	Cu-3.6 vol.% Al2O3 dispersion strengthened alloy was prepared by mechanical alloying (MA) of internal oxidation Cu-Al powders. The lattice parameter of Cu matrix decreased with milling time for powders milled in argon, while the abnormal increase of lattice parameter occurred in the air resulting from mechanochemical reactions. With a quantitative analysis, the combined method makes residual aluminum oxidized completely within 10-20 h while mechanical alloying method alone needs longer than 40 h . Lamellar structure formed and the thickness of lamellar structure decreased with milling time. The size of Al2O3 particles decreased from 46 to 22 nm after 40 h milling. After reduction, core-shell structure was found in MAed powders milled in the air. The compacted alloy produced by MAed powders milled in the argon had an average hardness and electrical conductivity of 172.2 HVand 82.1% IACS while the unmilled alloy's were 119.8 HVand 74.1% IACS due to the Al2O3 particles refinement and residual aluminum in situ oxidization.
10.1007-s11665-018-3148-6	-1		Protecting the surface of metals and alloys against corrosion and wear is of abundant importance owing to their widespread applications. In the present work, we report the improved anticorrosion and tribo-mechanical performance of copper (Cu) by a hard carbon (HC) coating synthesized in different pyrolysis temperature. Structural and surface characterization with roughness measurements was systematically investigated using various techniques. Effect of pyrolysis temperature on the corrosion behavior of coated Cu substrates in 0.6 M NaCl solution was evaluated via electrochemical impedance spectroscopy, potentiodynamic polarization. Pin-on-disk wear test of coated Cu substrate showed the influence of the pyrolysis temperature on the wear resistance performance of the HC coatings. According to the obtained results, it could be concluded that the HC coatings synthesized at 1100 A degrees C revealed an enhanced comprehensive performance, revealing their possible utilization as a protective coating for Cu substrates in chloride environment. Monte Carlo simulations have been utilized to elucidate the interaction between the Cu surface and HC coatings.
10.1007-s11665-018-3152-x	4	transformation; martensite; martensitic; phase; shape; beta; memory; shape memory; temperature; temperatures; martensitic transformation; gamma; transformation temperatures; effect; thermal	Shape memory alloys (SMAs) with cellular structure offer a unique mixture of thermo-physical-mechanical properties. These characteristics can be tuned by changing the pore size and make the shape memory metallic foams very attractive for developing new devices for structural and functional applications. In this work, CuZnAl SMA foams were produced through the liquid infiltration of space holder method. In comparison, a conventional CuZn brass alloy was foamed trough the same method. Functional performances were studied on both bulk and foamed SMA specimens. Calorimetric response shows similar martensitic transformation (MT) below 0 A degrees C. Compressive response of CuZnAl revealed that mechanical behavior is strongly affected by sample morphology and that damping capacity of metallic foam is increased above the MT temperatures. The shape memory effect was detected in the CuZnAl foams. The conventional brass shows a compressive response similar to that of the martensitic CuZnAl, in which plastic deformation accumulation occurs up to the cellular structure densification after few thermal cycles.
10.1007-s11665-018-3165-5	16	wear; composite; composites; powders; milling; particles; powder; wt; sliding; friction; hardness; matrix; mechanical; surface; properties	Cu-Zn-Al foams of varying porosity fractions using mechanical alloyed powder have been made through powder metallurgy route. Here, NH4 (HCO3) was used as a space holder. Mechanically alloyed Cu-Zn-Al is made using a planetary ball mill taking the ratio of Cu/Zn/Al = 70:25:5 (by weight ratio). The ball/powder ratios were varied in the four ranges 10:1, 15:1, 20:1, and 25:1. Green compacts of milled powder and space holder samples were sintered at three stages at three different temperatures 350, 550, and 850 A degrees C for 1 h at each stage. The crystalline size and particle size as a function of ball/powder ratios were examined. The compressive deformation responses of foams are varied with relative density and the ball/powder ratio. The plateau stress and energy absorption of these foams increase with an increase in relative density but decreases with increase in ball/powder ratio, even though crystalline size decreases. This has further been explained on the basis of particle morphology as a function of ball/powder ratio.
10.1007-s11665-018-3168-2	8	hot; deformation; strain; strain rate; dynamic; hot deformation; recrystallization; dynamic recrystallization; flow; rate; flow stress; compression; constitutive; degrees; stress	Hot compressive deformation behavior of the Cu-Zr-Ce alloy has been investigated according to the hot deformation tests in the 550-900 A degrees C temperature range and 0.001-10 s(-1) strain rate range. Based on the true stress-true strain curves, the flow stress behavior of the Cu-Zr-Ce alloy was investigated. Microstructure evolution was observed by optical microscopy. Based on the experimental results, a constitutive equation, which reflects the relationships between the stress, strain, strain rate and temperature, has been established. Material constants n, alpha, Q and ln A were calculated as functions of strain. The equation predicting the flow stress combined with these materials constants has been proposed. The predicted stress is consistent with experimental stress, indicating that developed constitutive equation can adequately predict the flow stress of the Cu-Zr-Ce alloy. Dynamic recrystallization critical strain was determined using the work hardening rate method. According to the dynamic material model, the processing maps for the Cu-Zr and Cu-Zr-Ce alloy were obtained at 0.4 and 0.5 strain. Based on the processing maps and microstructure observations, the optimal processing parameters for the two alloys were determined, and it was found that the addition of Ce can promote the hot workability of the Cu-Zr alloy.
10.1007-s11665-018-3292-z	6	grain; deformation; strain; strength; dislocation; cu-; tensile; size; ecap; grain size; sfe; ductility; hardening; high; stress	A hot rolling scheme (cross-rolling and unidirectional rolling) was adopted to process Cu-2.7Be sheets used as multiplier dynodes in photomultiplier. The effects of changing rolling direction on microstructure, texture and mechanical properties were studied by a combination of XRD, EBSD and TEM. It was found that higher copper-type texture and lower brass texture intensity were obtained in the ultimately cross-rolling (CR) sheet compared with the unidirectional rolling (UR) sheet.The EBSD results indicated that the grain orientation from mainly for UR sample turns to random for CR sample. Great enhancements in YS and UTS after unidirectional rolling were attributed to the massive and polygonal gamma precipitates. The CR sample exhibited lower anisotropy, because of the increase of S and gamma precipitates with spherical and tiny shape.
10.1007-s11665-018-3470-z	-1		This paper reports on the processing of Fe48Cr15Mo14Y2C15B6 amorphous alloy coatings on Cu-10%Ni (wt%) alloy using spark plasma sintering. The amorphous alloy coatings were sintered at temperatures ranging from 575 to 675 A degrees C at a pressure of 50 MPa. The development of microstructure, phases, and wear properties with sintering temperature of the coatings is investigated. The sintered coatings were found to be near fully dense with hardness close to that of the sintered bulk amorphous alloy. X-ray analysis indicated increasing degree of devitrification of the amorphous coatings with increasing sintering temperature. The wear behavior of the coatings is significantly influenced by the sintering temperature with volume wear rate first decreasing in the temperature range of 575-650 A degrees C and then increasing above 650 A degrees C. The variation in wear behavior is explained based on relative stability of the protective surface layer and embrittlement of the surface with the sintering temperature.
10.1007-s11665-018-3578-1	-1		The feature size effect is significant research interest in the field of microforming. It is assumed that the size effect is influenced by the material preparation process. To verify this, the feature size effects associated with the tensile yield strength of Cu sheets with thicknesses ranging from 100 to 200m, produced using different sequences involving annealing, rolling, and grinding, were studied. Differing feature size effects were observed in the Cu specimens, and it was confirmed that the size effect was indeed influenced by the specimen preparation sequence. The tensile yield strengths of the annealed-ground-rolled and annealed-rolled specimens increased as the specimen thicknesses decreased. However, an opposing size effect was observed in the case of the annealed-rolled-annealed, annealed-ground, and annealed-rolled-ground specimens. The reduction ratio did not alter the trend associated with the size effect, but influenced the intensity of the size effect. It is believed that the reinforcement and erosion of the surface-hardened layer introduced during rolling resulted in the contradictory results.
10.1007-s11665-018-3615-0	-1		Low-pressure die casting (LPDC) has been widely used to process aluminum and magnesium alloys; however, it has yet to be applied to manufacture brass alloys. This study investigates the microstructural evolution and mechanical behavior of a lead-free CuZnSiAl silicon brass via a variable-controlling approach on the basis of a faucet casting by LPDC. The manufactured silicon brass castings are predominantly composed of bcc -CuZn(Si, Al) and minor fcc -Cu(Zn, Si) solid solutions. The silicon brass castings also predominantly exhibit short rod-like or granular phases, which distinctly differ from the acicular morphology obtained by conventional gravity casting. The manufactured silicon brass castings which contain finer grains and short rod-like or granular phase exhibit superior mechanical properties. Their optimal mechanical propertieselongation of 15.0%, yield strength of 359.8MPa, and ultimate tensile strength of 598.9MPaare far superior to those of the typical lead brass HPb59-1. The results obtained in this study provide insight into the manufacture and design of lead-free silicon brass castings by LDPC.
10.1007-s11665-019-04391-7	2	corrosion; surface; film; electrochemical; films; spectroscopy; layer; current; solution; potential; resistance; composition; x-ray; ions; showed	This paper reports the changes in the electrochemical behavior of Cu60Zr25Ti15 bulk metallic glass (BMG) with the addition of 1 at% Mo and Nb in 3.5 wt% NaCl aqueous solution. Electrochemical methods employed for the study are open-circuit potential (OCP) and potentiodynamic polarization. The OCP values of the parent BMG and minor-alloyed BMGs differ only marginally. However, potentiodynamic studies show slightly higher corrosion resistance for the minor-alloyed BMGs than that of the parent alloy. Polarized surfaces of all the samples, examined under a scanning electron microscope (SEM), reveal pits formed due to corrosion. Corrosion products are analyzed by energy-dispersive spectroscopy (EDS) and X-ray photoelectron spectroscopy (XPS). Higher corrosion resistance observed for Nb- or Mo-added BMGs is attributed to the formation of NbO2/Nb2O5 and MoO2, respectively, besides the oxides of other constituent elements.
10.1007-s11665-019-04448-7	-1		Cu-Ag alloy is widely used as conductive material for high-field pulsed magnets in electrical industry. The cryorolling technique is considered as the most applicable severe plastic deformation technique. Therefore, in this study, cryorolling and subsequent annealing process were used to prepare Cu-4Ag (in wt%) alloy sheets. The strength, ductility and electrical conductivity of Cu-4Ag alloy sheets were investigated. Microstructure of Cu-4Ag alloy was also studied by OM, SEM, XRD and TEM. As a result, the cryorolling specimens after annealing at temperature of 300 degrees C display a good combination of tensile strength of 652.2 +/- 6.0 MPa, moderate elongation of 12.5 +/- 0.7% and electrical conductivity of 80.6 +/- 0.2% IACS. This is due to the presence of dislocations, dislocation cells, nanograins and nanotwins in the non-recrystallized regions and fine nanoscaled silver precipitates. Besides, a good ductility is achieved in this condition due to its desirable ductile fracture characteristics.
10.1007-s11665-019-04499-w	-1		In the present investigation, the high-temperature tensile behavior of Cu-3Ag-0.5Zr alloy in the solution-treated condition was evaluated in the temperature range of 27-700 degrees C using tensile testing, optical, scanning electron and transmission electron microscopy. The ultimate tensile strength of the alloy decreased with an increase in the test temperature. In the temperature range of 27-500 degrees C, the decrease in the yield strength was marginal, whereas at 600 and 700 degrees C, it reduced by 50% compared to that at room temperature. The total elongation increased with the temperature up to 600 degrees C and decreased thereafter. On the other hand, uniform elongation decreased with the increase in the temperature. Drastic drop in the uniform elongation at 500 and 600 degrees C is attributed to formation of cavities. The retention of yield strength at 400-500 degrees C was due to in situ aging by formation of silver precipitates. The mode of failure at all the tested temperatures was ductile with dimple rupture.
10.1007-s11665-019-04524-y	-1		Aging behavior of the Cu-Mg-Ce alloy of various cold deformations with aging temperature ranging from 400 to 480 degrees C and aging time ranging from 10 to 480 min was investigated. Effects of the secondary phase on hardness and electrical conductivity were discussed. Electrical conductivity and phase transformation kinetics equations were established. The addition of Ce promoted the precipitation of the secondary phase, improved the hardness, and delayed the dynamic recrystallization of the Cu-Mg alloy in the aging process. Nanoscale secondary phases in the aging process were determined to be alpha-Fe and Mg3P2. alpha-Fe particles lead to dispersion strengthening and the peak-aging stage. The Mg3P2 particles play an important role in inhibiting the motion of grain boundaries and the precipitation of coarse Fe2P or Fe3P. The secondary phases alpha-Fe and Mg3P2 pinned at dislocations and twin boundaries improved the softening resistance of the Cu-Mg-Ce alloy. Optimal aging parameters of the Cu-Mg-Ce alloy are 60% cold deformation aged at 420 degrees C for 20 min with 205.82 HV hardness, 73.59%IACS electrical conductivity, 597 MPa ultimate tensile strength, and 4.39% elongation.
10.1007-s11665-020-04588-1	-1		The unidirectionally solidified Cu-Al-Mn shape memory alloy with strong -oriented texture along the solidification direction and high length-diameter ratio columnar-grained structure exhibits excellent superelastic properties compared to the Ni-Ti alloys. In this paper, the tension-compression asymmetry of unidirectionally solidified Cu71Al18Mn11 alloy was researched by the geometrically nonlinear theory and superelastic experiments. The results show that the tension-compression asymmetry of the alloy has a significant anisotropy. The theoretical asymmetry ratio of transformation strain along reaches 14.2%, which is larger than other orientations. The tension and compression superelastic experiment research of unidirectionally solidified Cu71Al18Mn11 SMA along the direction parallel ( grain orientation) or perpendicular (- grain orientation) to the solidification direction indicates that their superelastic strain, transformation strain, elastic modulus, transformation platform slope, and critical stress have obvious tension-compression asymmetry.
10.1007-s11665-020-04619-x	8	hot; deformation; strain; strain rate; dynamic; hot deformation; recrystallization; dynamic recrystallization; flow; rate; flow stress; compression; constitutive; degrees; stress	Hot deformation tests of Cu-0.8 Mg and Cu-0.8 Mg-0.15 Ce alloys were carried out with a Gleeble-1500D thermal simulator in the temperature range of 500-850 degrees C and the strain rate range of 0.001-10 s(-1). Based on compression tests, flow stress-strain curves and processing maps of Cu-0.8 Mg and Cu-0.8 Mg-0.15 Ce alloys were plotted, and constitutive equations of the two alloys were constructed. The microstructure of the two alloys under different hot deformation conditions was observed and analyzed by optical microscopy. The trace addition of Ce restricted the movement of dislocations, promoted dynamic recrystallization, increased the flow stress and activation energy for hot deformation and enlarged the hot working region compared to the alloy without trace Ce addition.
10.1007-s11665-020-04794-x	17	wear; composites; coating; friction; composite; coatings; surface; tribological; properties; wear resistance; resistance; powder; sliding; matrix; wear rate	High-quality several-layer graphene film was fabricated on Cu-Ag alloy powder by in situ CVD at 900 degrees C, and three-dimensional graphene/copper-silver composites (Cu-Ag/G) were fabricated by spark plasma sintering (SPS). The analysis of XRD and EDS shows that the Ag element is uniformly dissolved in the matrix. The results of SEM, TEM and RAMAN show that several-layer graphene film was prepared in situ on the alloy substrate at atemperature as low as 900 degrees C has high quality and tightly wrapped around the matrix. The performance tests show that the tensile strength of Cu-Ag/G composites is 342 MPa, which is 23.5 and 33.1% higher than that of the unreinforced Cu-Ag (277 MPa) and Cu/G (257 MPa), respectively. The coefficient of friction of Cu-Ag/G composites is 0.23, which is 51 and 30% lower than Cu-Ag (0.47) and Cu/G (0.33), respectively. The corrosion potential of Cu-Ag/G composites shifted towards more positive values, and the corrosion current density decreased significantly. The corrosion inhibition efficiency of Cu-Ag/G reaches 74.70% which is stronger than Cu/G (45.39%), and the corrosion rate is 0.236 mm/year. The successful fabrication of Cu-Ag/G composites with excellent comprehensive properties provides a new way to further improve the performance of graphene/copper composites.
10.1007-s11665-020-04850-6	-1		In the present study, a TiB2 particle-reinforced Cu/Cu-0.5Cr composite was prepared by vacuum arc melting (VAM). The microstructure, mechanical properties and electrical conductivity of the composite after heat treatment were studied. The results show that the micro-nano dual-scale particle-reinforced TiB2/Cu-0.5Cr (VAM) composite possessed high strength, high hardness and high electrical conductivity. The nano-Cr particles were uniformly dispersed in the copper matrix, and the particle size was below 20 nm. The TiB2 particles were also uniformly dispersed and had good bonding with the copper matrix. After peak aging at 475 degrees C for 4 h, the comprehensive properties of the TiB2/Cu-0.5Cr (VAM) composite were improved. The hardness and electrical conductivity were 99.6 HBW and 82.3% IACS, respectively. The tensile test results show that the tensile strength of the TiB2/Cu-0.5Cr (VAM) composite was 401 MPa, which is higher than that of the TiB2/Cu (VAM) composite. The TiB2/Cu-0.5Cr (VAM) composite had high strength and hardness due to the strengthening of the micro-nano dual-scale particles and the good interface bonding. Based on the tensile fracture morphology of the composite, the failure mechanism of the composite was determined and is discussed.
10.1007-s11665-020-04956-x	3	sma; shape; shape memory; memory; smas; superelastic; bars; damping; cu-al-mn; mechanical; bending; applications; numerical; sma bars; material	This study focuses on the development of endodontic instruments manufactured from Cu-Al-Mn shape memory alloys (SMAs) which are more economical and easier to process as compared to conventional NiTi SMAs. Finite element analysis of three different numerical instruments was performed using material parameters of Cu-Al-Mn and conventional superelastic NiTi. Flexural and torsional stiffness of these instruments with the resulting von Mises stresses were evaluated under bending and twisting based on the ISO 3630-1 specification. All the studied Cu-Al-Mn endodontic files exhibited superior flexibility and lower reaction stresses as compared to NiTi endodontic files during bending, resulting from their low elastic modulus and starting stress value for the martensitic transformation. However, low torsional stiffness and high von Mises stress values related with the high angular displacement were obtained for Cu-Al-Mn endodontic instruments under torsional loading. Geometric differences of different models have been an important factor in adjusting the stiffness of endodontic instruments. Consequently, it was determined that Cu-Al-Mn SMA could be used as an alternative material in the manufacture of endodontic files that have large cross-sectional area and moment of inertia.
10.1007-s11665-020-05233-7	-1		In this paper, the effect of wire drawing on the microstructures, mechanical properties, and shape memory effect of compositions Cu-87.85-Al-11.70-Be-0.45 (CAB) and Cu-87.73-Al-11.70-Be-0.45-Zr-0.12 (CABZ) has been experimentally investigated. The wires with a diameter of 1.33 mm are manufactured from the casted round bars through the rolling and drawing (secondary) process. Investigations are performed on microstructure and phase for both as-cast and wire-drawn SMAs. Further, wire-drawn SMAs are investigated for phase transformation temperatures, hardness, ductility, and shape memory effect. The results show that the average grain size decreased with 73.06% by adding Zr to the CAB alloy. Further, the grain size of CABZ alloy wire decreased with 67.38% in the longitudinal direction and 67.07% in the transverse direction as compared to CAB alloy wire after the secondary process. Improvement of the grain structure in CABZ alloy wire resulted in an enhancement in the hardness of 13.86% in longitudinal and 12.43% in the transverse direction, and tensile strength of 134.58% and ductility of 177.06%. The phase transformation temperatures reduced by the addition of Zr, and better shape recovery is observed in CABZ alloy wire. [GRAPHICS] .
10.1007-s11665-020-05353-0	-1		Cu-Ti alloys are one of the main candidates to act as a substitute for Cu-Be alloys due to their more environmentally friendly nature. Cu-Ti alloys are age hardenable alloys, and their treatments can modify their microstructure, causing the formation of various Cu-Ti intermetallic that can strongly influence both the mechanical and corrosion properties. In this work, the effect of homogenization heat treatment at 1173 K followed by aging at 723 K for different times (0-24 h) on the microstructure, corrosion and mechanical properties of Cu-4.5 wt%Ti alloy was investigated. Moreover, the corrosion mechanism based on the different kinetics for the formation of the protective oxide layer was studied. The microstructure and phase analyses were analyzed with SEM and XRD. The mechanical properties were investigated by microhardness test, whereas the corrosion properties were studied by potentiodynamic anodic polarization and potentiostatic tests in artificial sweat. The results showed that the cast sample had the highest corrosion resistance, and the mechanical properties decrease with the homogenization treatment and increase after the combination of homogenization and aging. A corrosion mechanism correlated to the amount and type of intermetallic material was proposed.
10.1007-s11665-020-05371-y	15	aging; strength; conductivity; electrical conductivity; electrical; mpa; treatment; strengthening; degrees; cu-; cold; precipitation; tensile strength; tensile; iacs	Given the sub-rapid solidification characteristics of twin-roll strip casting (TRSC), the solidification structure and growth process of precipitates during aging treatment were studied. The results showed that TRSC could refine the solidification structure and inhibit the microsegregation of Cu-3.2Ni-0.75Si alloy. During aging treatment, the precipitates mainly consisted of rod beta-Ni3Si and disk delta-Ni2Si. The precipitate size was increased by increasing the aging time, which altered the mechanism of precipitation strengthening. Also, the experimental results indicated that precipitate strengthening arises either from the cutover mechanism or from the Orowan mechanism. Furthermore, the Avrami equation, which describes the kinetics of phase transformation and electrical conductivity during aging were established for the Cu-Ni-Si alloy, and the calculated results are consistent with the data. The Cu-3.2Ni-0.75Si alloy after aging treatment at 450 degrees C for 4 h exhibited optimum performance, and the tensile strength and electrical conductivity were as high as 711 MPa and 43.2% IACS, respectively.
10.1007-s11665-020-05381-w	-1		The hot tensile test was applied to study the influence of sulfur content on the high-temperature mechanical properties of C71500 Cu-Ni alloy. The hot processing map of C71500 alloy was established according to the test results. It is found that the increase of sulfur content has no visible effect on the tensile strength of C71500 alloy at high temperature, but has a great effect on the elongation and reduction area of fracture. Through optical microscopy, scanning electron microscopy and energy-dispersive x-ray spectroscopy analysis of fracture samples, it can be qualitatively determined that the composition of sulfur inclusions is (Mn,Fe,Ni)S, which is plastically deformable in the process of hot deformation. However, due to the difference of plasticity between the inclusions and the matrix, stress concentration is easy to occur, thus reducing the overall plasticity of C71500 alloy. Based on the proposed dynamic material model theory, the processing maps with different sulfur contents were established, which could show the destruction effect of sulfur on the high-temperature plastic deformation of C71500 alloy.
10.1007-s11665-021-05470-4	-1		In this work, the cold metal transfer (CMT) welding technique was used to additive manufacture Cu-6.6%Al-3.2%Si alloy. A dual wire feeding approach was adopted to separately feed SAFRA CuSi3 wire and AlSi5-ER4043 wire into the molten pool. To overcome the defect of non-uniform sample height, the CMT welding head was used in the round-trip configuration to deposit the samples. The deposited samples were characterized for their (1) microstructure and (2) mechanical properties of hardness and tensile strength . Microstructural characterization was done using optical microscopy (OM), scanning electron microscopy and transmission electron microscopy. From the elemental analysis, the central region of the deposited layer was enriched in aluminum and depleted in silicon compared to the region at the border of the layer. Evaluation of the mechanical properties showed that the deposited samples had good strength and ductility. The addition of silicon and manganese effectively improved the hardness and tensile strength properties of the deposited alloy.
10.1007-s11665-021-05643-1	-1		Wire-arc additive manufacturing (WAAM) based on cold metal transfer (CMT) welding process has been used to fabricate Cu-6.5 wt% Al alloy by simultaneously feeding two separate wires. The deformation behavior of as-fabricated Cu-6.5 wt% Al alloy and heat-treated Cu-6.5 wt% Al alloy under quasi-static (0.1 s(-1)) tension was investigated. The obtained tensile results show that the heat treatment can improve the mechanical properties. The enhancements of strength and ductility originate from the work-hardening capacity and fine grain due to solid solution strengthening. The TEM characterization of the samples has shown the existence of deformation twinning. The optical micrographs have shown that during the tensile process, cracks are first formed inside the large grains, and then the cracks propagate, which cause dendritic columnar structure are broken into fragments.
10.1007-s11665-021-05790-5	2	corrosion; surface; film; electrochemical; films; spectroscopy; layer; current; solution; potential; resistance; composition; x-ray; ions; showed	Through marine natural environment tests, the corrosion behavior of T2 and B30 Cu-Ni alloy at different seawater depths of the South China Sea was studied. The corrosion morphology and corrosion product properties were investigated using different techniques, including 3D optical microscope, scanning electron microscope (SEM), x-ray diffraction analyzer (XRD) and electrochemical impedance spectroscopy (EIS). Based on the environmental factor monitoring data and corrosion rate data, environmental factor influence mechanism on corrosion behavior was discussed The results indicated that the corrosion rate of T2 decreased with seawater depths increasing, while it was opposite for that of B30 Cu-Ni alloy. The evolution law of the corrosion rates of T2 at different seawater depths was mainly controlled by changes in seawater temperature and dissolved oxygen concentration. The effect of hydrostatic pressure was limited on T2 corrosion rate, but high hydrostatic pressure could promote Cl- penetrating into the corrosion product film, forming a uniform corrosion morphology for T2. For B30 Cu-Ni alloy, it was simultaneously affected by dissolved oxygen concentration and hydrostatic pressure, and the corrosion product film was rich in Ni and Fe elements.
10.1007-s11665-021-05825-x	-1		This paper examines the influence of 0-0.2 wt%B-doping on the microstructure, mechanical properties, and pseudoelastic behavior of Cu-Al-11.5-Be-0.57 shape memory alloys (SMAs). This microstructure study reveals that the addition of boron leads to significant grain refinement in beta(1)-type polycrystalline Cu-Al-Be SMAs. A maximum refinement size of 50 mu m was achieved with the addition of 0.15 wt%B. The fine-grained (Cu-Al-11.5-Be-0.57)-B-0.15 SMA with serrated grain boundaries exhibited the maximum enhancement of ultimate tensile strength, 744.65 +/- 29.34 MPa, and ductility of 21.93 +/- 0.56%. The fracture morphology revealed the transformation of intergranular to transgranular fracture in the SMAs with boron-doping. Maximum pseudoelasticity of 4% was achieved in the SMA with 0.15 wt%B and suits as a damper in seismic applications.
10.1007-s11665-021-05833-x	-1		The bendability of Cu alloys is a critical property for many electronic components. In this study, the effects of annealing, aging and cold rolling on microstructural evolution and bending properties of Cu-Cr-Zr alloy sheets were investigated in details. The results showed that the decrease of the bending properties of Cu-Cr-Zr alloy sheets arose from the increase of annealing time, aging time, and rolling deformation. The annealing and aging treatment had little influence on the variation of bending properties between bending axis along rolling direction and transverse direction. However, the increase of rolling deformation led to a great difference in bending properties of the rolled alloy between rolling direction and transverse direction. The enhancement of Copper texture ({112}) during rolling resulted in a decrease in bending properties of Cu-Cr-Zr alloy sheet with bending axis along transverse direction while the decease of bending properties of the alloy sheet with bending axis along rolling direction was due to an increase in Brass texture ({110}). The results can be used to provide guidance for the design of highly bendable copper alloy sheets.
10.1007-s11665-021-05969-w	-1		The high strength, elasticity, hardness and wear resistance of C17200 copper means it is widely used in motor brushes, bearing sleeves and contact parts. As the requirement for extended reliability and service life of industrial products increases, the demand for high-performance copper-beryllium (Cu-Be) will also increase. In this work, the wear mechanisms of C17200 alloy against GCr15 steel under dry conditions and in a 3.5% NaCl solution were investigated. X-ray diffractometry, scanning electron microscopy, energy-dispersive x-ray spectroscopy, a three-dimensional profilometer, and x-ray photoelectric spectroscopy were used to evaluate the wear damage and analyze the wear mechanisms involved. The results showed that the wear mechanisms of C17200 alloy under dry wear conditions were mainly adhesive wear, oxidation wear and delamination. During tribocorrosion, the effect of friction promoted the oxidation and corrosion of the specimen surface. The main wear mechanisms of tribocorrosion in a 3.5% NaCl solution were peeling and corrosion wear. In addition, the NaCl solution provided lubrication and could effectively reduce the wear of the materials. The results may guide improvement of the serviceability of Cu-Be materials in industrial environments.
10.1007-s11665-021-06266-2	-1		Copper and copper alloys own high thermal conductivity, electrical conductivity, good plasticity, and corrosion resistance, which are widely used in electric power, aerospace, and marine engineering. Due to low absorption rate of infrared and near infrared light, high thermal conductivity and high activity with oxygen, laser cladding of copper, and copper alloys are difficult to be conducted in air since the problems associated to cracks and voids are always hardly to be eliminated. In this paper, C-Al2O3-Cu composite powder mixed with Ni and Fe was developed to solve these problems. Use of carbon was to depress the oxidation and improve the laser absorption, while alumina was used to improve the laser absorption and mechanical strength . To improve the bonding strength between cladding layer and substrate, Ni and Fe were used. Experimental results showed that no obvious aggregation was observed and the powder showed good fluidity. The tensile strength of the cladding layer is 406.7 +/- 0.1MPa which is about 1.7 times higher than that of pure copper substrate, and the tensile fracture of the cladding layer revealed microporous aggregation fracture due to the existence of Al2O3 in the cladding layer.
10.1007-s11665-021-06409-5	-1		A dense Cu-10Sn alloy bulk specimen was obtained by optimizing the laser powder bed fusion (L-PBF) processing, and the relative density of the specimen reached 99.7%. The grain morphology was mainly the columnar dendrite and inter-dendritic phases generated along the solidification direction. Tensile testing and detailed microstructural characterization were carried out on specimens in the as-built and heat-treated condition. Under the quasi-static tensile condition, the yield strength (sigma(0.2)), ultimate tensile strength (UTS), and the elongation of the as-built Cu-10Sn specimen were 392 MPa, 749 MPa and 29%, respectively. After the solution treatment at 800 degrees C for 4 h, and aging treatment at 400 degrees C for 2 hours, the microstructure of the specimen transformed from the columnar grain to equiaxed grain, the dislocation density decrease, and numerous annealing twins were observed in the heat-treated state. Therefore, the quasi-static tensile yield strength (sigma(0.2)) of the specimen was reduced to 245 MPa. However, the UTS and the elongation were increased to 840 MPa and 56%, respectively, due to the interaction between annealing twins and equiaxed grain.
10.1007-s11665-021-06415-7	16	wear; composite; composites; powders; milling; particles; powder; wt; sliding; friction; hardness; matrix; mechanical; surface; properties	Development of sustainable machining processes and technologies for manufacturing of the leadless free-cutting brass parts has been widely taken under consideration due to the legislative actions restricting the use of toxic lead in industry. In this study, the two-dimensional (elliptical) ultrasonic vibration-assisted turning (UAT) was employed to machine the newly designed Cu-35Zn-1.89Al leadless free-cutting alloy. Machinability of the alloy was compared to conventional continuous turning (CT) in terms of cutting forces, chip morphologies and surface roughness. The effect of process parameters of cutting speed and feed rate was also investigated during CT and UAT. It was found that UAT had the ability to reduce the energy consumption by 47.5 percent compared to CT. Results of the machinability evaluation showed that the resultant force was reduced up to maximum amount of 60.3 percent by using UAT. The UAT process could also promote the surface roughness between 28.3 and 37.2 percent in comparison with CT.
10.1007-s11665-021-06450-4	-1		A powder metallurgy-based strategy to in situ construct a three-dimensionally interconnected hexagonal boron nitride (3Di-hBN) layers surrounding the grains of Cu-Ni matrix through metal-organic chemical vapor deposition process was utilized to fabricate 3Di-hBN-reinforced Cu-0.7-Ni-0.3 (3Di hBN-Cu-Ni) composite. The effect of 3Di-hBN on the mechanical properties of 3Di hBN-Cu-Ni composite was assessed by comparing with pure Cu-Ni alloy (without hBN) fabricated via powder metallurgy route under similar processing conditions. Uniaxial tensile investigations showed that 3Di-hBN positively influenced the mechanical properties of 3Di hBN-Cu-Ni composite; similar to 16.3, similar to 11.67, and similar to 27.9% higher yield strength, UTS, and fracture toughness, respectively, compared to PM Cu-Ni alloy. The overall improved performance of 3Di hBN-Cu-Ni composite was attributed to the formation of 3Di-hBN layers at the interfaces of Cu-Ni grains, which enable the composite to withstand the applied load through the mechanisms of load transfer, dislocation strengthening, and grain refinement. In addition, thermal conductivity of 3Di hBN-Cu-Ni composite was found similar to 10% higher than that of pure Cu-Ni alloy.
10.1007-s11665-021-06459-9	17	wear; composites; coating; friction; composite; coatings; surface; tribological; properties; wear resistance; resistance; powder; sliding; matrix; wear rate	Graphene oxide nanosheets reinforced Cu matrix composites were prepared using ball milling process and spark plasma sintering (SPS). Effects of ball milling times on morphology of composites powders were studied. Furthermore, microstructure evolution and properties of sintered composites were investigated. Results show that the size and shape of the composites gradually transformed from regular sphericity to flake with the increase in ball milling times. Correspondingly, the average flake diameter of Cu alloy powders increased gradually from 7.2 +/- 0.5 to 25.0 +/- 1.0 mu m. Compared with the matrix alloy, the tensile strength of the composites increases significantly and the elongation decreases gradually. For 20 h of ball milling, the yield strength of composites increased by 35% from 126 to 170 MPa, and elongation decreases from 44 to 31%. However, for 60 h of ball milling, the tensile strength and yield strength increased to 290 and 211 MPa, respectively, while the elongation significantly descends. Besides, during the ball milling, the conductivity of composite gets a slight decrease owing to the increasing degree of powder defects.
10.1007-s11665-021-06485-7	-1		This paper studied the electrical resistivity of in situ Cu-Fe microcomposites using theoretical analysis and experiments. The model alloys Cu-XFe (X = 3, 4.3, 11, 14 and 17 wt%) were produced by casting, and the microcomposites were prepared by thermomechanical treatment. The solid solubility of iron in the copper matrix was measured using an energy dispersive spectrometer. The electrical resistivity and conductivity was evaluated using a micro-ohmmeter. The conductivity of the Cu-XFe (X = 3 and 4.3) was essentially constant at similar to 40% IACS. The conductivity of the Cu-XFe (X = 11, 14, 17) microcomposites decreased in a nonlinear manner with increasing iron content and increasing cold deformation strain, which was mainly determined by the interface scattering resistivity caused by the interface between the copper matrix and the iron fibers.
10.1007-s11665-022-06804-6	-1		Direct aging a casting to a T5 temper may be a suitable, cost-effective alternative to two-stage precipitation heat treatment schedules for some industrial applications. However, its successful implementation requires an in-depth understanding of the associated phase transformations and their influence on material properties. Hence, this study established the relationships between microstructure, hardness, and electrical conductivity, realized by the direct aging of industrial B319 Al alloy. Samples with various solidification rates and Sr contents were treated at 250 degrees C for durations up to 24 h, followed by Rockwell hardness and eddy-current electrical conductivity measurements. These data were complemented with novel, in situ analysis of the elevated-temperature microstructural transformations, using high-resolution electron microscopy and x-ray diffraction techniques. Even without prior dissolution and homogenization, direct aging produced extensive precipitation and coarsening of fine theta ' and theta-Al2Cu phases, yet the products of transformations were localized in the solute-enriched regions near the interdendritic phases. The associated alleviation of as-cast lattice strains substantially enhanced alloy conductivity by up to 5% International Annealed Copper Standard (IACS), yet reduced hardness by up to 15 HRB, independent of the casting prehistory. Therefore, T5 heat treatments at 250 degrees C can be advantageous for high-conductivity Al components designed for low-stress applications.
10.1007-s11665-022-06912-3	-1		In recent years, the interest with niobium alloys has been increasingly focusing on high-stress applications. This work shows the study of Cu-25wt%Fe-25 wt%Nb composite sintered by spark plasma at 700, 750, and 800 degrees C, under constant uniaxial pressure of 35 MPa for 3 min, evaluated for use as bushings. The scanning electron microscopy results showed regions rich in Nb and alpha-Fe embedded in a gamma-Cu matrix, forming a solid solution of Fe-Nb suggesting the occurrence of a sintering process by Cu liquid phase and precipitation of an epsilon-phase Fe2Nb Laves. The relative density, mechanical and thermophysical properties were also evaluated. The alloy sintered at 800 degrees C showed hardness around 81 HB, low porosity, low porosity, yield strength 168 +/- 4 MPa, modulus of elasticity 47 +/- 4 GPa, and relative density 7.9% higher than the alloy prepared at 700 degrees C. The values of thermal conductivity obtained were above 70 Wm(-1)K(-1), superior to SAE 65, indicating a possible material for application on bushings.
10.1007-s11665-022-06936-9	-1		In this work, an ultrafine-grained Cu-1wt%Al2O3 composite was prepared by a high-pressure torsion (HPT) technique using Cu and nano-Al2O3 powder. The effect of temperature on the microstructures and mechanical properties was investigated. Compared with consolidation at room temperature, both the tensile strength and plasticity were improved when the Cu-1wt%Al2O3 composite was consolidated at elevated temperature, and an amazing 1077.8 +/- 40.9 MPa tensile strength was obtained if Cu-1wt%Al2O3 composites were first HPT consolidated at room temperature followed by consolidation at elevated temperature.
10.1007-s11665-022-06991-2	-1		Although nanostructure offers several advantages in improving the performance for Cu alloys prepared by mechanical alloying, the excellent properties have not been obtained to date primarily due to a single strengthening method or the Fe contamination introduced by the stainless steel grinding tank and balls. Herein, we added Cr to regulate the milling process and control the content of Fe doped into the Cu matrix. And the effects of Cr on the morphology, crystallite size, lattice strain and properties of Cu were studied. The results showed that adding an appropriate amount of Cr could prevent more Fe from being doped into the alloy matrix. When the Cr content was lower than 0.2 wt%, the work hardening could be accelerated, so that the Cu alloys had smaller crystallite size, greater internal strain and higher tensile strength . But with continuous increase in Cr content, the crystallite sizes of the alloys began to increase again. Nevertheless, the nanostructured Cu alloys with particle size less than 10 nm were still obtained. In conclusion, by appropriately adjusting the Cr content, we demonstrated an improvement in the properties of the Cu alloys. The optimum properties were achieved by Cu-0.2 wt% Cr with tensile strength of 517 MPa, ductility of 7.28% and electrical conductivity of 73.37% IACS. And the study provided a new idea for overcoming the Fe contamination in the metal matrix, and further improving high-performance Cu alloys through the combination of fine-grain strengthening and alloy strengthening.
10.1007-s11665-022-06997-w	6	grain; deformation; strain; strength; dislocation; cu-; tensile; size; ecap; grain size; sfe; ductility; hardening; high; stress	This paper presents the effect of a new processing technique called hard cyclic viscoplastic deformations (HCVD) on the enhancement of mechanical and electrical properties in a copper-chromium alloy. A modern severe plastic deformations (SPD) technique named Indirect Extrusion Angular Pressing (IEAP) was also implemented to refine the microstructure before HCVD. Samples were processed by IEAP, HCVD, and IEAP followed by HCVD, and the evolution of microstructure, mechanical properties, and electrical conductivity was analyzed. Results of materials characterization revealed that HCVD dissolved the Cr particles, reduced the microstrains, and transformed the elongated microstructure to an equiaxed structure in the SPD-induced copper. Results of mechanical testing showed that HCVD enhanced the elongation of SPD-processed samples at the cost of a slight decrease in strength and hardness. Further, aging treatment at different temperatures was conducted on the samples. Results showed that HCVD-processed samples retained the dislocation densities in the microstructure and possessed the highest hardness and electrical conductivity after aging. Such enhancement was attributed to the effect of HCVD on the relaxation of severely deformed grain boundaries as well as the contribution of HCVD to the full dissolution of Cr residuals, and subsequently, the formation of Cr sub-precipitates after aging.
10.1007-s11665-022-07016-8	-1		Commercial high strength and high electrical conductivity Cu-0.67Cr-0.3Zr alloy was directionally solidified and subsequent aged. The specific strengthening mechanism of FCC and BCC structured chromium precipitations was discussed in detail. The strengthen effect of FCC Cr precipitation with a size less than 35 nm follows shear strengthening mechanism, while that of BCC Cr precipitation with size greater than 1.4 nm follows non-shear strengthening mechanism. After aging treatment, the yield strength of the alloy with a solidification rate of 50 mu m/s increases from about 140 to 205 MPa, which is due to the transformation of Cr precipitation from FCC to BCC. Besides, the matrix purification caused by phase transformation increases the electrical conductivity. In addition, the wear resistance of the alloy is also improved with the increase in strength . These excellent properties make the alloy have the potential to be competent as the high-speed railway contact lines.
10.1007-s11665-022-07112-9	-1		The oxidation kinetics of Cu-Pb bearing alloys was investigated under a temperature domain between 25 and 700 degrees C. It has been found that during oxidation process, lead was easy to diffuse in the channel formed inside the alloy and form oxide film on the surface of the alloy. The oxides formed by Pb at different oxidation temperatures show different morphologies, and there was no obvious change at 25 degrees C. However, the PbO formed by oxidation at 180 and 300 degrees C was spherical, and the Pb3O4 formed by oxidation at 500 degrees C was small flake distribution. At 700 degrees C, granular PbO was covered on the alloy surface. Sn and Cu were oxidized to SnO2 and CuO. Pb3O4 and PbO as oxidation products of Pb diffused at the alloy surface as the oxidation period increased. The oxidation weight gain curve of Cu-Pb alloy followed a parabolic law for 300 h at 25 degrees C. As the time increased, a straight line is noticed very close to zero. For a temperature range between 180 and 700 degrees C, the oxidation weight gain curves followed again a parabolic law.
10.1007-s11665-022-07336-9	6	grain; deformation; strain; strength; dislocation; cu-; tensile; size; ecap; grain size; sfe; ductility; hardening; high; stress	In the current research, an ultrafine-grained (UFG) copper was manufactured by rolling and cooling-assisted friction stir processing. The impact of traverse speed on the microstructural evolution and mechanical properties of fabricated copper was investigated. All samples were defect-free except the 600-100 (60%) sample. The pre-rolled samples had a grain size lower than the annealed samples due to the presence of higher pre-strain in the 60% samples. For the pre-rolled samples, with increasing the traverse speed from 100 to 200 mm/min, the average grain size was decreased from 1.1 to 0.8 mu m owing to the reduction in the heat input. Based on the obtained results, fabrication of UFG pure copper by 60% cold rolling followed by only one pass of cooling-assisted friction stir processing was possible. There was a uniform microstructure in the stirred zone due to the high cooling rate of samples caused by the high thermal conductivity of pure copper and the water-cooling system. In the pre-rolled samples, with increasing the traverse speed from 100 to 200 mm/min, the hardness was enhanced from 109 to 116 HV owing to decreasing the grain size. Also, in the 60% samples, with increasing the traverse speed to 200 mm/min, the yield strength and ultimate tensile strength increased to 340.9 and 343.8 MPa, and the total elongation decreased to 7.5% owing to the reduction in grain size to 0.8 mu m. The 600-100 (60%) sample had a very low strength (134.1 MPa) and poor ductility (1.2%) due to the presence of many cavities in the stirred zone. All FSPed samples (except 600-100-60%) revealed a ductile fracture. By applying the cooling-assisted friction stir processing, the size and depth of dimples were reduced due to the lower grain size of the FSPed samples.
10.1007-s11665-022-07362-7	-1		The present work reports a detailed scheme of designing Cu-Ni alloy thin film in nanostructured form for use as coating on the structural components in naval vessels through molecular dynamics (MD)-based approaches. The nanostructured Cu-Ni alloy thin film has sufficient corrosion resistance against sea water. A properly designed Cu-Ni alloy thin film with highest possible hardness can provide high wear resistance against the flowing sea water containing suspended particles. In the present work, the most potent Cu-Ni alloy thin film with regard to hardness has been designed by means of MD-based nanoindentation modelling under varying alloy composition and grain/crystallite size. Apart from the mechanical properties, MD techniques have been used for estimating some of the physical properties, viz. lattice parameter, cohesive energy, intrinsic stacking fault energy of Cu-Ni alloys in their bulk form with varying alloy compositions. The intrinsic stacking fault energy is found to decrease initially, reaches to a minimum value, and then increases with addition of Ni in the alloy. This type of variation in stacking fault energy is the reason for the highest hardening effect usually obtained at some intermediate alloy composition in any substitutional type binary alloy. The melting point of the nanoparticles of same alloy has been estimated here for spherical shaped Cu-Ni alloy nanoparticles of 10 nm size with varying alloy compositions through both equilibrium and non-equilibrium MD approaches. The non-equilibrium approach which resembles experimental method has resulted into a phase diagram indicating the variation of melting point of Cu-Ni alloy nanoparticle with the variation in Ni content in the alloy under the specific rate of heating.
10.1007-s11665-022-07497-7	-1		We investigated the influence of aging on the microstructure and properties of a deformation-processed Cu-Ni-Co-Si alloy. Aging caused recovery and recrystallization in the Cu matrix and the precipitation of Ni2Si, Cu15Si4 and CoSi. At the temperature of 350 degrees C, increasing aging time caused the hardness to increase to a peak value at 0.5 h, and subsequently to decrease at longer aging times. At higher temperatures, the hardness decreased with increasing aging time. The conductivity and elongation to fracture increased with increasing aging time and tended to saturation at about 4 h . The hardness, conductivity and plasticity of the alloy cold rolled at 47% reduction, after the optimal aging treatments at (i) 350 degrees C for 0.5 h, (ii) 400 degrees C for 1 h, (iii) 500 degrees C for 0.5 h, were (i) 262 HV, 45.8%IACS and 3.6%; (ii) 249 HV, 48.1%IACS and 4.4%; (iii) 230 HV, 49.8%IACS and 5.5%, respectively. Based upon our results, we recommend the adoption of the optimized process.
10.1007-s11665-022-07532-7	2	corrosion; surface; film; electrochemical; films; spectroscopy; layer; current; solution; potential; resistance; composition; x-ray; ions; showed	The passivation behavior, electrochemical properties and semiconducting properties of the passive film formed on a Cu-25Zn-15Ni alloy in borate buffer solutions at various pH conditions were studied. Potentiodynamic polarization investigations revealed a wide range of passivation independent of pH values. The passive currents and acceptor density were found to be linearly proportional to the applied passivation potentials. The passive films were identified as p-type semiconducting materials through Mott-Schottky measurements. Calculations based on the point defect model (PDM) showed that the derived acceptor density decreased exponentially with increasing applied passivation potential, while the alloy exhibited good corrosion resistance due to its low acceptor diffusivity. The surface morphology of the passive films was examined using scanning electron microscopy (SEM), and the surface composition was characterized using x-ray photoelectron spectroscopy (XPS).
10.1007-s11665-022-07563-0	-1		In this work, high alumina Cu-12.5Al alloy was selected as the base alloy, in which a different Mn content was added to prepare the powder core wire with a structure resistant to element burning. Arc melt deposition process was applied to produce Cu-12.5Al-xMn(x:1,2,3,4,5wt%) alloy. The micromorphology, phase composition, grain size, and shape memory properties are studied. Results show that the shape recovery rate of Cu-12.5Al-xMn alloy is maintained at more than 65% under 4% pre-strain, and it reaches the highest when the Mn content is 3wt%. At the same time, the shape recovery rate of the Cu-12.5Al-3Mn alloy has reached 84.43% under 6% pre-strain. In addition, the alloy completed the bending test under 10% pre-strain and had a shape recovery rate of 64.93%. According to the analysis, the shape memory properties are directly related to the grain refining effect of the special heat and mass transfer behavior of melt droplets wrapped with unmelted particles in the powder core wire. It is also affected by structure transformation, the number of martensitic populations, and its order degree.
10.1007-s11665-022-07697-1	-1		In traction power supply catenary systems of high-speed railways, integral droppers convey current for the use of the electric locomotive. Based on real electro-mechanical coupling conditions of high-speed rail catenary droppers, the microstructure and fracture morphology formation and changes of the copper magnesium alloy wire (Cu-Mg0.4) resulting from the effect of current pulses of low density (10 A/mm(2)), short durability (0.25 s), and interval (5 min) were studied in this work, accompanied by low dynamic stress (30 MPa) and compression strain (0.3%) under long-term working cycles. The simulation and test results indicated the temperature increase in the droppers in the working state was slightly higher than room temperature. In these experiments, a large number of micropores were generated in the pre-rolled alloy wire droppers. Under the long-term action of low stress and amplitude pulse coupling fields, the droppers retained the fiber structure characteristics without obvious recrystallization; however, similar shear band structures appeared in the fiber structures, which were bent and deformed, and the micropore density increased. The micropores aggregated into microcracks and expanded, resulting in a gradual decrease in plasticity, and the fracture mode transformed from ductile trans-granular fractures to brittle inter-granular fractures, corresponding to deeper and shallower dimples, respectively.
10.1007-s11665-023-07810-y	8	hot; deformation; strain; strain rate; dynamic; hot deformation; recrystallization; dynamic recrystallization; flow; rate; flow stress; compression; constitutive; degrees; stress	This study researched how Ce addition affects the microstructure and mechanical behavior of Cu-Fe-Ti-Mg alloys during hot compression. A thermal deformation simulation machine was used to study the hot compression process at 0.001-10 s(-1) strain rates and 500-950 degrees C deformation temperatures. The true stress-strain curves and constitutive equations were obtained for the two alloys. Based on the electron backscatter diffraction analysis, the addition of Ce can improve the dislocation density and texture strength of the Cu-Fe-Ti-Mg alloy. The microstructure and precipitates of the Cu-Fe-Ti-Mg-Ce alloy were also analyzed. The average grain size of the Cu-Fe-Ti-Mg-Ce alloy is smaller than the Cu-Fe-Ti-Mg alloy. The addition of Ce delayed dynamic recrystallization. These findings provide a theoretical foundation for understanding the Ce addition effects on the hot deformation behavior of the Cu-Fe-Ti-Mg alloy, serving as a reference for industrial manufacturing of the alloy.
10.1007-s11665-023-07932-3	-1		The quasi-in situ electron backscatter diffraction method was used to investigate the microstructure and orientation evolution of Cu-45 at% Ni alloy during the recovery process. For the first time, the triple junction movement theory was verified in a Cu-Ni alloy instead of in the pure metal. The Y-junction movement was found to be the dominant recovery mechanism in the common lamellar grains. However, this theory did not apply to grains in the area deformed by shear. Unlike the microstructure evolution, the orientation evolution was the same in the areas not deformed and deformed by shear. All the Goss orientations were swallowed by other orientations, whereas all the cube orientations swallowed other orientations. This study helped better understand the recovery process in Cu-Ni and other face-centered cubic alloys after rolling and annealing processes.
10.1007-s11665-023-07972-9	-1		Wire arc additive manufacturing (WAAM) is an approach to develop unique and sophisticated design products in comparison to other traditional techniques. In the present study, the components of Cu-Si alloy have been developed using WAAM with a robotic gas metal arc welding technique. In this process, the current and voltage varied from 70 to 110 A and 17 to 19 V, respectively. The effect of process parameters on the microstructure, hardness, and wear behavior of components have been studied in details. The results show that the surface roughness of the components reduced with the increase in current and voltage. The microstructure of the uppermost surface of WAAM components shows columnar followed by dendritic with equiaxed morphology. The process parameter also affects the mechanical and wear resistance properties of WAAM components. The results show that the microhardness (from 100.03 to 160.03 HV) and wear resistance of the Cu-Si alloy component increase with the increases in current and voltage.
10.1007-s11665-023-07981-8	-1		Recrystallization behavior of cold-rolled (85%) Cu-Cr-Nb-Zr alloy was studied with the aid of differential scanning calorimetry (DSC), hardness test, optical microscopy and electron backscattered diffraction (EBSD). The activation energy for recrystallization, as determined from DSC thermograms using the Kissinger, Boswell and Ozawa methods, was found to be in the range of 209-226 kJ mol(-1). The DSC thermograms were analyzed to estimate the recrystallization fraction as a function of temperature, and these results were fitted to a sigmoidal curve. The recrystallization temperature was estimated from these sigmoidal curves and found to linearly increase with the heating rate (10-40 degrees C min(-1)). The recrystallized fraction obtained from DSC studies was compared to that obtained from grain orientation spread (GOS) maps and hardness tests, with good agreement found between the three methods. The results from the DSC analysis were further validated by applying recrystallization parameters to cold-rolled sheets of the Cu-Cr-Nb-Zr alloy and through microstructural examination.
10.1007-s11665-023-08222-8	-1		The effect of the stud angle on the microstructure and mechanical properties of the pure copper sheets processed by constrained studded pressing (CSP) was investigated experimentally and numerically. The microstructure of the CSPed samples was studied using optical microscopy and transmission electron microscopy, and the dislocation density in the samples was determined using the Debye-Scherrer spectrum. The mechanical properties, including ultimate tensile strength, yield stress, elongation, and microhardness, were also measured. The results show that the first pass of the CSP caused the crystallite size in both die sets to decrease to nanometer sizes and the dislocation density in the samples increased significantly. The 60 degrees dies induced a higher strain and a more severe dislocation accumulation and hence a more severe dynamic recovery in the Cu samples than the 30 degrees dies, which caused the UTS of the samples obtained from the 60 degrees dies to decrease more than that in the 30 degrees dies after it reached to its maximum. It is shown that one pass of CSP with a 30 degrees stud angle can achieve better ultimate tensile strength in pure copper sheets compared to the groove pressingf or constrained groove pressing methods.
10.1007-s11665-023-08264-y	16	wear; composite; composites; powders; milling; particles; powder; wt; sliding; friction; hardness; matrix; mechanical; surface; properties	Performance evaluation of electrode material in terms of metal removal rate and relative electrode wear is very much essential to assess the quality of components machined by the electric discharge machining process. Electrode materials perform differently due to their composition, electrical conductivity, and thermo-mechanical properties. Therefore, detailed experimental investigations have been carried out to understand the effect of different copper alloys, current, voltage, and pulse on time on the metal removal rate and relative electrode wear during the electric discharge machining process. Taguchi L-9 orthogonal array has been employed using Cu-Cr-Zr, Cu-Cd, and Cu-Be as tool material. The results reveal that Cu-Cr-Zr is the most suitable tool material for spark erosion machining of AISI D2 die steel to depict low electrode wear and high metal removal rate. The best machining conditions obtained with Cu-Cr-Zr tool material for maximum metal removal rate and minimum relative electrode wear are current 15 Amp, voltage 80 V, and pulse on time 36 mu s. Scanning electron microscope is used for analysis of all the three electrode materials against different machining conditions. The role of tool material and electric discharge machining process parameters in developing micro-cracks, deposition on the tool surface, and recast layer formation were demonstrated.
10.1007-s11665-023-08567-0	-1		Cu-1.5 wt% Zn alloy used in the present study was subjected to the hot impression creep tests at three stresses of 75, 110 and 150 MPa and three temperatures of 250, 300 and 350 & DEG;C for a constant dwell time of 2 h . The effect of stress and temperature on the impression depth with respect to time was studied. Irrespective of the test condition, the depth of impression increased with respect to the time. However, upon increasing the applied stress, the twins were observed. Stress exponent values and activation energies were determined for different test temperatures and stresses. Stress exponent values related to the plastic flow over the complete range of experimental conditions were found to lie between 4 and 5.5. Whereas the average activation energy value was determined to be 164 & PLUSMN; 10 kJ/mol. Calculated stress exponents and activation energy values reveal the dislocation climb phenomenon, controlled by dislocation pipe diffusion as the mechanism of the creep.
10.1007-s11665-023-08699-3	2	corrosion; surface; film; electrochemical; films; spectroscopy; layer; current; solution; potential; resistance; composition; x-ray; ions; showed	The corrosion behavior of Al/Ni-doped Cu alloys in seawater environments was investigated. Results indicated that increasing immersion temperature significantly worsened the corrosion resistance of Cu alloys in soil simulation and 3.5 wt% NaCl solution. With the increase of stray current densities, the proportion of CuCl was significantly increased. The presence of stray current seriously destroyed the oxide film on the sample surface, thereby resulting in the deterioration of corrosion resistance.
10.1007-s11665-023-08778-5	2	corrosion; surface; film; electrochemical; films; spectroscopy; layer; current; solution; potential; resistance; composition; x-ray; ions; showed	Long-term corrosion behaviors of copper-zinc alloy (H62) and copper-nickel alloy (B30) in a typical marine atmospheric environment are systemically investigated in this work. Microstructural characterization and electrochemical tests show that pitting corrosion occurs on H62 alloy, and the bottom of the pits is dendritic due to preferential dezincification, whereas B30 exhibits uniform corrosion with a relatively compact corrosion product after long-term exposure. The outermost and innermost layers (accounting for 9.7% and 43.8% of the entire thickness of the corrosion products, respectively) with copper enrichment exist on B30, and the middle layer is enriched with nickel oxide. The annual weight loss rate for H62 is 1.5 times larger than for B30 (approximately 4.65 g m-2 y-1), indicating an improved corrosion resistance for the nickel addition compared to zinc. Furthermore, the Warburg impedance across the corrosion pits increases with the exposure period for H62 alloy due to the slower oxygen or soluble ion diffusion therein, which demonstrates that the pit growth becomes slow as the corrosion products thicken before re-passivation.
10.1007-s11665-023-08939-6	2	corrosion; surface; film; electrochemical; films; spectroscopy; layer; current; solution; potential; resistance; composition; x-ray; ions; showed	Cu/Al clad plates are widely used in the aerospace, electric power, metallurgical and chemical industries and for architectural decoration. Understanding the corrosion behavior of Cu/Al clad plates is of vital importance to effectively avoid catastrophic failures due to acid rain. The impact of H+ on the corrosion behavior of Cu/Al clad plates was studied. The corrosion mechanism of Cu/Al clad plates was dominated by both chemical corrosion and electrochemical corrosion, which was influenced by the pH values of the acid solution and the types of anions. The corrosion current density decreased from 0.51 mu A cm-2 to 0.02 mu A cm-2 as the pH increased, while Rct increased from 6.5 x 103 +/- 1.3 x 103 ohm cm2 to 1.3 x 104 +/- 8.8 x 103 ohm cm2, indicating that the corrosion rate decreased as well. Furthermore, numerous copper ions were replaced by Cu particles due to chemical corrosion. The Cu particles (the cathode) covered the aluminum, which formed countless microgalvanic cells with aluminum (the anode) to accelerate the corrosion rate.
10.1007-s11665-023-09048-0	2	corrosion; surface; film; electrochemical; films; spectroscopy; layer; current; solution; potential; resistance; composition; x-ray; ions; showed	This study investigates the long-term corrosion resistance of Cu-10Ni and Cu-20Ni alloys in simulated seawater. Weight loss tests, electrochemical impedance spectroscopy, and linear polarization resistance tests were conducted to evaluate the corrosion behavior of the alloys for 300 days with 30-day intervals. The results indicate that the Cu-20Ni alloy exhibits superior corrosion resistance to the Cu-10Ni alloy due to the higher electron work function and better protective properties of the oxide formed on its surface. Pitting corrosion occurred in both alloys, with the Cu-10Ni alloy displaying a higher corrosion rate. The results showed fluctuation in polarization resistance in both alloys with time which was due to the creation and transformation of passive films on the surface of the alloy, which can destabilize and deteriorate with time. It was found that the corrosion resistance of copper-nickel alloys can vary based on their composition and the environmental circumstances, and the establishment of a consistent and effective passive film is vital in augmenting their corrosion resistance.
10.1007-s11665-024-09524-1	-1		Enhancement of solid solubility in binary immiscible Cu-Co system due to thermodynamic contribution from ternary Mn addition and kinetic contribution from use of rapidly solidified ribbons as the precursor of ball milling has been investigated. The impact of ternary addition on the binary system's free energy change at various concentrations and grain size has been estimated by employing the thermodynamic model proposed by Miedema incorporating appropriate modifications for ternary addition. The solid solubility results obtained from x-ray diffraction analysis of the rapidly solidified ribbons have been compared with the results obtained by the thermodynamic calculation, and an attempt has been made to identify the potential attributes contributing to the mechanically induced solid solubility in the immiscible systems. High-resolution transmission electron microscopy (HRTEM), differential thermal analyzers (DTA) and x-ray diffraction (XRD) have all been used to characterize the phase advancement during rapid solidification, mechanical alloying and isothermal annealing. Using a superconducting quantum interference device magnetometer (SQUID), magnetic characteristics have been investigated. Following annealing in the ball-milled Cu-Co-Mn alloy at 550 degrees C for 1 h, the ideal combination of magnetic characteristics was achieved.
10.1007-s11665-024-09631-z	-1		In this paper, the tribocorrosion behavior of 70/30 Cu-Ni alloy in 3.5 wt% NaCl solution at different polarization potentials was investigated. The cathodic potentials (- 0.6,-0.3 VAg/AgCl), OCP and anodic potentials (- 0.15, 0 VAg/AgCl) were selected for the tribocorrosion tests, and the wear marks were examined by optical microscopy (OM), scanning electron microscopy (SEM), energy dispersive spectrometer (EDS), confocal laser scanning microscopy (CLSM) and x-ray photoelectron spectroscopy (XPS). The wear micro-morphology and chemical composition were characterized. The results showed that the tribocorrosion loss volume increased with the increase of polarization potential. At the cathodic potential (- 0.6 VAg/AgCl), flaking layer and furrow appeared on the surface of the wear scar, and the wear forms were delamination wear and abrasive wear. At OCP, the corrosion product layer produced by selective corrosion played a lubricating role, but the corrosion promoted the formation of subsurface cracks and holes, and the loss volume was about three times of that of the pure mechanical wear. Intergranular corrosion greatly accelerated material degradation when the polarization potential increased to 0 VAg/AgCl.
10.1007-s11665-024-09739-2	-1		In this paper, classical molecular dynamics simulations of tensile deformation on Cu50Zr50 metallic glass alloy composite nanowires have been carried out, followed by stress-strain behavior predictions using supervised machine learning (ML) algorithms. The composite NWs contain spherical copper nanocrystallites embedded in the Cu50Zr50 metallic glass matrix. The composite NWs are subjected to strain rates in the range of 5 x 10(7) s(-1)-1 x 10(9) s(-1) at different temperatures of 450-650 K. The stress-strain curves show elastic-plastic regions, and as expected, the yield stress values decrease with increased deformation temperature. Yield strength values in the range of 1.15-1.85 GPa are observed. Flow softening and flow localization are observed beyond the yield at all temperatures and strain rates during deformation. Furthermore, the effect of several other independent variables such as composition, crystallite size, and cooling rate on the stress-strain response and mechanical properties is also studied. Six regression models are used for the prediction of complete stress-strain behavior. The Extreme Gradient Boost, ANN, and Gradient Boot models gave better stress-strain curve prediction with coefficients of determination 96.2%, 96.6%, and 97.6%. Whereas the models Ada Boost, Decision tree, and Random forest gave similar to 86% prediction. Overall, the ML models accurately predict the effect of independent variables on the hot deformation stress-strain characteristics in the studied temperature and strain rate range. Therefore, the time, cost, and number of experiments can be reduced for understanding the mechanical behavior.
10.1007-s11665-024-09962-x	14	strength; properties; conductivity; electrical; mechanical; cu-; grain; mpa; electrical conductivity; aging; precipitation; phase; mechanical properties; tensile; phases	Effects of solid solution treatment on the microstructure and properties of a Cu-1.9Co-0.48Si alloy were investigated. The solid solution treatment temperatures and durations significantly affected the Cu-Co-Si alloy's final properties. The hardness-conductivity product increased with the solid solution treatment temperature. After SST at 1050 degrees C for 5 min, cold rolled (85% deformation), and aged at 450 degrees C for 2 h, the studied Cu-Co-Si alloys have a hardness of 258 HV and an electrical conductivity of 56% IACS. The concurrently enhanced hardness and conductivity can be attributed to high-density nano-precipitates and dislocations. These findings can provide a reference for developing high-performance Cu-Co-Si alloys.
10.1007-s11665-024-10173-7	-1		Nanoindentation is widely used for estimating mechanical properties (reduced elastic modulus (Er) and hardness (H)) of materials at small length scale. In the present work, the focus is to observe the effect of the unloading fraction on Er and H values for Cu and Cu-Al alloys. Thus, to accomplish this work, single and multiple cycles (partial/complete) indentations are performed where maximum load (Pm) varies from 1000 to 9000 mu N and the unloading fraction is varied from 20 to 100%. Our results show that load vs. depth of penetration (P-h) curves follow a similar pattern for single and multiple cycles (partial/complete) indentations. Interestingly, a prominent hysteresis loop is observed in the case of multiple cycle indentation for 80-100% unloading fraction. It is noticed that the loop area increases with the addition of Al atoms due to a higher amount of energy released during unloading, hence it requires more energy during reloading for further plastic deformation. Finally, it is seen that the difference in Er and H values between single and multiple cycles (partial/complete) indentations is insignificant (+/- 10%) for all samples. In addition, H values are validated with residual indent impression area acquired for all samples.
10.1007-s11665-024-10176-4	-1		The Cu-13wt% Al-3.5wt% Ni-0.7wt% Ti- (0, 0.5, 1) wt% Y alloy was produced from a powder mixture by mechanical alloying, sintering and hot rolling. The mechanically alloyed powders were compressed, sintered, hot rolled, and heat treated to prepare a bulk alloy with a martensitic phase. Also, the effects of yttrium addition (0.5 and 1 wt%) were studied on the properties of produced powder and bulk alloy. X-ray diffraction (XRD) analysis proved the formation of (Cu-Al-Ni) alpha phase after 20 h milling and martensite formation after hot rolling and heat treatment of the alloy. Optical and scanning electron microscope (SEM) images showed little amounts of porosity after hot rolling and heat treatment. It is found that adding yttrium caused a better distribution of alloying elements in the matrix by creating a secondary intermetallic phase (probably Al3Y) and a finer grain size. Hardness measurements indicated an increment in hardness from 158 HV for Y-free alloy to 187 HV in 1wt% Y-containing alloy. The transformation temperatures of these samples were determined by differential scanning calorimetry (DSC). Yttrium addition affected the shape memory properties by increasing the martensite-to-austenite transformation temperature from 41.5 degrees C for Y-free alloy to 58.5 degrees C in 1wt% Y-containing alloy after hot rolling and heat treatment.
10.1007-s11665-024-10447-0	2	corrosion; surface; film; electrochemical; films; spectroscopy; layer; current; solution; potential; resistance; composition; x-ray; ions; showed	The process of electrodeposition of Cu-Ni-W thin films is discussed in the article, utilizing an aqueous sulfate-citrate bath . The current density was varied within the range of-5 to-60 mA/cm2. The high-resolution field emission scanning electron microscopy analysis illustrated that the films possess a uniform, dense microstructure and a metallic luster. Upon inspection of the cross-sectional micrograph, it was determined that the film thickness ranges from 1 to 1.2 mu m. Additionally, the energy-dispersive spectroscopy findings disclosed that the films were rich in copper, with copper content ranging from 59 to 92 wt%. Tungsten content was found to vary between 1 and 36 wt%, and nickel content ranged from 4.6 to 11.6 wt%. The atomic force microscopy confirmed that films were quite smooth with the minimum average roughness of 1.7 nm for the film deposited at a current density of-5 mA/cm2. X-ray photoelectron spectroscopy analysis has verified the existence of metallic Cu, Ni, W, and their oxidized states on the external layer of the films. The maximum hardness of 2 GPa and elastic modulus of 74 GPa were obtained from the nanoindentation tests. It was found by Tafel polarization that film deposited at a current density of-5 mA/cm2 exhibited the corrosion resistance of 8626 ohm-cm2 when compared to films deposited at higher current densities. The greater charge transfer resistance of 7112 ohm cm2 obtained by the electrochemical impedance spectroscopy also indicated the corrosion resistance characteristics of these deposits.
10.1007-s11665-024-10500-y	-1		Copper-nickel alloys have received much attention in the last decades due to their high electrical, thermal, mechanical, and magnetic properties which mainly depend on their composition. In this paper, copper-nickel alloy coatings onto indium tin oxide substrate were elaborated by electrodeposition in pulsed current mode with optimized current density and deposition time. The electrodeposition is subsequently followed by thermal treatment under controlled atmosphere. The surface morphology and the chemical analysis of the elaborated coatings were assessed by scanning electron microscopy associated to x-ray microanalysis. Their structural analysis was performed by x-ray diffraction, and the Vickers microhardness test was conducted to examine their mechanical properties. Moreover, the adhesive strength of the copper-nickel coatings was evaluated using a progressive scratch test, while a multi-pass scratch test was employed to assess their wear resistance. The results showed that the copper-nickel coating obtained with optimized current density (- 20 mA/cm2) and heat treated at 600 degrees C for 1 h under controlled atmosphere exhibits high mechanical properties; the microhardness increases from 133 to 280 HV, and the adhesion strength from 32 to 203 MPa. On the other hand, optimized electrodeposition conditions followed by thermal treatment led to thinner characteristic XRD pics of Cu-Ni coating indicating an increase in crystallinity from 12 nm to 44 nm. Mechanical characteristics underlined a high resistance to scratches, a decrease in the friction coefficient, and an increase in the dissipated energy which reaches 20 J for heat-treated Cu-Ni coating. These results highlighted a homogeneity in morphology, and low porosity improving the CuNi coatings adhesion strength to the substrate.
10.1007-s11665-024-10575-7	-1		Cu-0.6 at%Cr (Cu-Cr) and Cu-0.6 at%Cr-0.6 at%Ta (Cu-Cr-Ta) alloys were prepared by mechanical alloying combined with spark plasm sintering. The effective refinement of the microstructure along with the significantly increased dislocation density in Cu-Cr alloy is achieved through the introduction of Ta. Most precipitates transform from Cr precipitates into Cr2Ta Laves phases with semi-coherent interfacial structure, which provides the effective inhibition effect to dislocation movement and grain coarsening, along with significantly enhanced mechanical properties. Compared with Cu-Cr alloy, 25% and 24% enhancement for the yield strength (413 MPa) and ultimate tensile strength (497 MPa) is realized by Cu-Cr-Ta alloy along with the acceptable elongation of 13.1%. It is worth noting that the significant improvement for high-temperature mechanical properties is also realized through the introduction of Ta, showing the 130% and 124% enhancement of yield strength and ultimate tensile strength at 450 degrees C, respectively. The softening temperature of Cu-Cr-Ta alloy reaches 1015 degrees C, which is 16% higher than that of Cu-Cr alloy (876 degrees C). This study provides an effective approach to improve the mechanical properties and softening resistance of the traditional Cu-Cr alloys under the elevated temperature environment, which has a great potential application in the field of future fusion reactor.
10.1007-s11665-025-10953-9	-1		The objective of this study was to examine the variations in flow stress and microstructure of the Cu-3.08Be alloy at the temperature ranging from 680 to 830 degrees C within the strain rate range of 0.01-10 s-1. The Arrhenius constitutive model and dynamic materials model (DMM) were established, and the 3D hot processing map and optimal processing parameters were obtained. It was observed that higher strain rates led to elevated levels of flow stress. The optimal processing temperature range for the alloy was determined to be between 780 and 820 degrees C, with a strain rate of 0.01-0.1 s-1, and an activation energy Q value of 281.33 KJ/mol. The evolution of dislocations, sub-grains, and dynamic recrystallization (DRX) grains was analyzed using Electron Backscatter Diffraction (EBSD) and Transmission Electron Microscopy (TEM) techniques. Initially, as the strain rate increased, a significant number of dislocations entangled around the secondary phase particles, resulting in pronounced particle-stimulated nucleation (PSN) effects characterized by an increase in recrystallized volume fraction while dislocation density decreased; additionally, low-angle grain boundaries transformed into high-angle grain boundaries. In the alpha (Cu), recrystallization driven primarily by the precipitation-stimulated nucleation effect (PSN) is the dominant softening mechanism, complemented by continuous dynamic recrystallization (CDRX) induced by progressive sub-grain rotation. Within the beta phase, CDRX remains as the primary softening mechanism.
10.1007-s11665-025-10983-3	17	wear; composites; coating; friction; composite; coatings; surface; tribological; properties; wear resistance; resistance; powder; sliding; matrix; wear rate	A Cu-15Ni-8Sn coating was fabricated on the surface of 2205 duplex stainless steel using the high-velocity air fuel (HVAF) spraying technique. The microstructure of the coating was characterized by advanced electron microscopies. Hardness tests and wear performance evaluations under oil-lubricated conditions were conducted on the coating. The results indicate that the coating is consisted of nano gains with the grain sizes ranging from 60 to 80 nm and the alloying elements completely dissolving into the Cu matrix. The coating has a hardness of HRC 29.2. Under the conditions of evaluating the wear performance, the coating exhibits a stable friction coefficient of 0.05 similar to 0.14 and a wear rate of (1.66 similar to 3.89) x 10(-8) mm(3)/mm, much better than the wear performance of bulk Cu-15Ni-8Sn materials with the same hardness and nano precipitates. Further analysis on the worn surfaces and debris was conducted, and the wear mechanism of the coating was discussed. Overall, the Cu-15Ni-8Sn solid-solution nanocrystalline coating demonstrated excellent mechanical and tribological properties, indicating its potential for application in part repair, performance enhancement, and service life extension.
10.1007-s11665-025-11014-x	-1		This work investigated the influence of different NH4Cl concentrations (0, 10, 50, 100 mg/L) on the corrosion behavior of B30 Cu-Ni alloy in simulated seawater by various tests. The results show that as NH4Cl concentration increases, the passivation region shranks, i(p) increases, E-p decreases and the defect density inside the surface passivation film rises, which demonstrate that the existence of NH4+ weakens the corrosion resistance of the alloy. Furthermore, when the NH4+ concentration increases to 50 mg/L, a clear transition zone appears, as well as the number and size of pitting increase, indicating that the passivity of B30 alloy is declined, and the pitting degree is heightened. The H+ caused by hydrolysis of NH4+ promotes the passivation film disruption, and impairs its protective performance.
10.1007-s11665-025-11035-6	-1		A Cu-0.69Cr-0.08Zr-0.07RE alloy was produced using practical non-vacuum smelting and one-pass hot and cold extruding. Refined primary grains and evenly distributed Cr and Zr were obtained in as-cast alloy because of high cooling rate. The grains were gradually refined under three-direction compressive stress and shear strain during hot and cold extruding with large deformation of near 90%. Ultrafine grains, high density of dislocations and nano-precipitates were obtained after solid solution, cold extruding and aging. Dislocations contribute most, nano-precipitates come in second and grain boundaries last to the strength . The number and even distribution of nano-precipitates were promoted by the increased saturability of Cr and Zr atoms in copper matrix and promoted decomposition of the supersaturated copper matrix. High density of dislocations was retained and their interaction with boundaries/sub-boundaries and nano-precipitates still functioned under higher aging temperature. This gave the alloy high tensile strength of 669 MPa and 642 MPa after aging at 425 degrees C and 500 degrees C, respectively, for 1.8 h . The strength decrement was mainly caused by growth of the nano-precipitates. Conductivity higher than 72%IACS was obtained in aged alloys. The residual resistance of the low-temperature aged alloy was mainly caused by nano-precipitates, and the residual Cr and Zr elements dissolved in the matrix.
10.1007-s11665-025-11044-5	15	aging; strength; conductivity; electrical conductivity; electrical; mpa; treatment; strengthening; degrees; cu-; cold; precipitation; tensile strength; tensile; iacs	Cu-1.0Cr-0.25Zr-0.3Mg alloys were fabricated by vacuum induction melting, cast in a copper mold and subjected to multi-step deformation-aging treatment. Through the synergistic effect of precipitates and dislocations, we successfully achieved high conductivity of 98.7% IACS, high hardness of 192.2 HB and high strength of 559.7 MPa in Cu-1.0Cr-0.25Zr-0.3Mg alloy. Different from the traditional treatment, this study adopts a new multi-step deformation-aging treatment, which can effectively improve the decrease in conductivity caused by deformation, strengthen the contribution of dislocations and precipitates, and achieve dual-phase strengthening. Compared with single-step deformation-aging, the properties are greatly improved and the plasticity is restored. After single-step treatment, two types of nano-precipitates appear in the alloy, which are semi-coherent ellipsoidal Cr phase and spherical Heusler phase CrCu2(ZrMg), which are dispersed near the dislocation line. After multi-step treatment, the size of CrCu2(ZrMg) particles is 4-6 nm, which is smaller than before. The Cr particles are even finer in size, only 3-5 nm. The multi-step deformation-aging strengthening effect is the result of the interaction between the dislocations, precipitates and residual solute atoms.
10.1007-s11665-025-11232-3	-1		In this study, the microstructure, crystal structure, martensitic transformation, and shape memory effect of Cu-18.5Zn-14Sn-2.5Fe (wt%) single crystal were investigated. The single crystal was obtained solely through direct annealing of a corresponding cast alloy. It comprises three distinct phases: a leaf-type phase corresponding to the alpha-Cu(Zn, Sn) phase, randomly distributed nanoprecipitates composed of alpha-Fe, and a beta(CuSn) phase as the matrix. The martensitic transformation starting temperature (Ms) for this alloy is 233 K. Compression tests reveal that the single crystal exhibits a complete shape memory effect for deformations below 7%.
10.1007-s11665-025-11333-z	14	strength; properties; conductivity; electrical; mechanical; cu-; grain; mpa; electrical conductivity; aging; precipitation; phase; mechanical properties; tensile; phases	Proper thermomechanical treatment can enhance the comprehensive performance of Cu-Fe alloys. This research delves into the microstructure and properties of Cu-7Fe-0.3Mg alloy to uncover the microstructure evolution and the aging precipitation mechanism throughout thermomechanical treatment. The as-cast Cu-7Fe-0.3Mg alloy exhibits a predominance of spherical, as well as some branching dendritic, iron-enriched regions. Following plastic deformation, the Fe-rich phases are fragmented and elongated into rod-like shapes along the rolling direction. Throughout the aging treatment, the alloy contains two distinct precipitate sizes. As the time and temperature of the aging treatment increase, the quantity of precipitates increases, while the concentration of dislocations density diminishes. At the peak aging conditions of 460 degrees C for 8 hours, the precipitates are uniformly distributed across the alloy, primarily ranging in dimensions from 10 to 25 nm. Further increases in aging time and temperature lead to significant coarsening of precipitates and clustering phenomena. After peak aging treatment, the alloy exhibits excellent comprehensive performance, with electrical conductivity, microhardness, and tensile strength reaching 59.67% IACS, 200.23 HV, and 553.27 MPa, respectively. The strengthening and electrical conduction mechanisms suggest that the precipitation of Fe-rich phases is pivotal in enhancing the comprehensive performance.
10.1007-s11665-025-11420-1	-1		In this study, Cu-Zn-Al-Fe beta-brass alloys were prepared through homogenization annealing and hot-rolling annealing. The effects of Zn and Al contents on the microstructure and mechanical properties of beta-brass alloys were assessed. The results show that Cu-Zn-Al-Fe beta-brass alloys comprise beta(CuZn) matrix phases and beta 1(FeAl) phases with three orders of magnitude: micron, submicron, and nano. By employing appropriate Zn and Al contents, excellent microstructures featuring diffusive nano-beta 1(FeAl) can be achieved. However, excessive amounts of Zn and Al promote the formation of a brittle gamma(Cu5Zn8) phase, which seriously affects the properties of the alloy. After compositional optimization, two alloys exhibit excellent overall mechanical properties. The ultimate tensile strength, yield strength, and elongation were 673.9 MPa, 410.3 MPa, 17.9% for Cu-30Zn-6.5Al-2.5Fe alloy, and 611.1 MPa, 350.2 MPa, and 25.0% for Cu-28Zn-6.5Al-2.5Fe alloy, respectively. The excellent overall mechanical properties can be attributed to a combination of factors, including the synergistic precipitation strengthening of beta 1(FeAl) at the micron scale (Orowan mechanism) and the nanometer scale (shear mechanism), solid solution strengthening induced by the addition of Zn and Al, and dislocation strengthening provided by the formation of a large number of dislocations after rolling. This study provides an essential reference for preparing high-performance brass alloys and helps to broaden the application of beta-brass in industry.
10.1007-s11665-025-11619-2	8	hot; deformation; strain; strain rate; dynamic; hot deformation; recrystallization; dynamic recrystallization; flow; rate; flow stress; compression; constitutive; degrees; stress	In this study, the hot deformation behaviors of Cu-Nb composites reinforced by niobium strip were investigated by hot tensile test at temperatures from 600 to 780 degrees C and strain rates from 0.001 to 1 s-1. The microstructure evolution of Cu-Nb composites reinforced by niobium strip were analyzed by SEM and EBSD. The results show that the adiabatic shear bands were formed during the hot deformation at high strain rate and high temperature, which were very easy to crack. However, the dynamic recrystallization of material was significant at the low strain rate and high temperature, and the equiaxed crystal structures were formed. The hot processing maps of Cu-Nb composites based on the dynamic material model were drawn and analyzed, it was shown that the safe and unstable regions of plastic processing were quantitatively analyzed, and the high-temperature deformation mechanism of Cu-Nb composites was revealed.
10.1007-s11665-025-11620-9	-1		In this study, Cu-10Pb-10Sn/steel bimetallic samples were prepared using the solid-liquid composite method for Cu-10Pb-10Sn alloy. The friction and wear behavior of Cu-10Pb-10Sn alloy and GCr15 stainless-steel rings under various loads, sliding speeds, and lubrication media were systematically investigated using a ring-block friction testing device. Experiments were conducted under dry friction, kerosene lubrication, and oil lubrication conditions, focusing on the coefficient of friction, wear volume, wear rate, abrasive wear morphology, and wear surface characteristics. The wear mechanism of the Cu-10Pb-10Sn alloy under the different conditions was also analyzed. The results demonstrate that, under three working conditions-dry friction, kerosene lubrication, and oil lubrication-the wear rate and wear volume of the alloy vary differently with changes in load and rotational speed. Additionally, the friction mechanism evolves differently under each of these conditions. Under dry friction conditions, wear severity is reduced at high speeds. Under kerosene lubrication, the wear behavior is comparable at high speeds and high loads. Oil lubrication is more suitable for high-speed conditions. The combined multi-case tribological performance of Cu-10Pb-10Sn alloys demonstrates the best tribological performance under oil lubrication. This study provides a theoretical basis for the selection of lubricants and the optimization of lubrication conditions. Additionally, it provides practical guidance for the design and operation of piston pump components, while also advancing the development of lubrication technology in the field of tribology.
10.1007-s11665-025-11683-8	-1		This study examines the impact of heat treatment on the microstructure, pore distribution, and electrical and thermal properties of pure copper prepared by selective laser melting (SLM). SLM copper was subjected to various heat treatment temperatures ranging from 200 to 1000 degrees C. The findings reveal that increasing heat treatment temperatures result in relative density decreasing from 99.8% in the as-built state to 99.4% due to small increase in porosity. Heat treatments in the range of 200 to 400 degrees C lead to recovery in microstructure reducing low angle boundaries among grains. The electrical conductivity improves from 90.26 to 92.8% IACS, and thermal conductivity increases from 374 to 389 W/mK along the building directions after treatment at 400 degrees C. This work uniquely demonstrates the anisotropic thermal expansion behavior of SLM copper and reveals the role of high-temperature pore migration in causing a sharp decline in thermal conductivity at temperatures above 800 degrees C. Additionally, a detailed correlation is established between recrystallization, the formation of high-angle grain boundaries, and the enhancement of electrical conductivity. By annealing at temperatures above 600 degrees C, recrystallization and the formation of high-angle grain boundaries lead to the diffusion of pores to grain boundaries, increasing coefficient of thermal expansion. Pores migrating to grain boundaries result in the dropping of thermal conductivity to 342 W/mK, while electrical conductivity increases to 99.8%% IACS due to a decrease in dislocation density and grain boundaries. The slight increase in pores results in adverse effect on thermal conductivity in annealing after overly high temperature treatments. Thermal expansion resulting from redistribution of pores further leads to change in the dimension of SLM Cu parts. These results indicate that heat treatment can markedly alter the properties of SLM-manufactured copper compared to traditionally fabricated copper. This study provides in-depth observations on dimensional stability and physical properties of the additive manufactured pure copper for industrial applications.
10.1007-s11665-025-11702-8	14	strength; properties; conductivity; electrical; mechanical; cu-; grain; mpa; electrical conductivity; aging; precipitation; phase; mechanical properties; tensile; phases	To clarify the effect of Y addition on the microstructure and properties of Cu-Ti-Ni alloy, the first-principles calculation was employed to investigate the influence of Y on the diffusion behavior of solute Ti and Ni elements in the Cu-Ti-Ni-Y alloy, and the microstructures and properties of as-cast and aged Cu-3Ti-3Ni alloys with varying Y contents were characterized and tested as well. The simulation indicates that the incorporation of Y significantly accelerates the diffusion of Ti and Ni elements, thereby promoting phase precipitation. The increased Y content results in a remarkable increase in the number of primary phases, which is consistent with the simulation. After solution treatment at 900 degrees C for 4 h and aging at 550 degrees C for 7 h, the electrical conductivity of Cu-3Ti-3Ni-0.07Y can reach 35.66%IACS, while the hardness value can maintain 310 HV, and the elastic modulus reaches up to 150.44 GPa. The superior mechanical properties can be primarily attributed to the dispersed nano-sized beta '-Cu4Ti phases during aging, whereas the enhanced electrical conductivity arises from the less solubility of Ti in the Cu matrix due to the formation of a large number of CuNiTi and NixTi phases.
10.1007-s11665-025-11728-y	14	strength; properties; conductivity; electrical; mechanical; cu-; grain; mpa; electrical conductivity; aging; precipitation; phase; mechanical properties; tensile; phases	A new Cu-Ni-P alloy was synthesized through electroless plating and spark plasma sintering (SPS), followed by a series of heat treatment processes. These results indicate that electroless plating effectively coats the surface of the Cu particles with a uniform Ni-P layer. As the content of Ni-P increases, precipitates of P and Ni form at the grain boundaries, leading to an increase in the mechanical properties of the alloy, accompanied by a reduction in electrical conductivity. The alloy with the composition of Cu-4.8Ni-0.5P with less precipitates exhibits good mechanical properties and electrical conductivity. The optimal comprehensive properties were achieved when the alloy was aged at 450 degrees C for 8 h, with abundant nanoscale precipitates of Ni2P and Ni12P5, resulting in a hardness of 181.55 HV and a conductivity of 33.86% IACS.
10.1007-s11665-025-11881-4	-1		To avoid the unstable friction coefficient and severe wear of conventional Cu-matrix friction material used as the brake pads for high-speed trains, the matrix alloying method based on high-temperature and high-strength copper alloys was used to enhance the service performance. Three kinds of friction materials based on Cu-Ni-Al, Cu-Ni-Cr, and Cu-Ni-Si high-temperature and high-strength copper alloys were obtained by powder metallurgy, and their mechanical and tribological properties were studied in this work. The results show that the hardness and compressive strength of the friction materials are significantly enhanced by the solid-solution strengthening and second-phase precipitation strengthening. High-temperature and high-strength copper alloy matrix friction materials have excellent tribology performance. Among these, Cu-Ni-Al matrix friction material demonstrates the best tribological performance. Compared to commercial pure Cu matrix friction material, the wear rate of Cu-Ni-Al matrix friction material at room temperature is reduced by 59%, and the friction coefficient stability is enhanced by 75%. At high temperature, the wear rate of Cu-Ni-Al matrix friction material is reduced by 62%, and the friction coefficient stability is increased by 36%, which is expected to meet the service requirements of the brake pads of higher-speed trains.
10.1007-s11665-025-11884-1	14	strength; properties; conductivity; electrical; mechanical; cu-; grain; mpa; electrical conductivity; aging; precipitation; phase; mechanical properties; tensile; phases	With the rapid advancement of industrial applications, the demand for high-performance copper alloys has significantly increased. Copper alloys combining high strength, superior electrical conductivity, and excellent wear resistance are urgently required in modern industries. To balance the mechanical properties and electrical conductivity of the hot-rolled Cu-1.0Cr-0.1Zr alloy, the effects of annealing and aging treatments on its comprehensive performance were systematically investigated. The results demonstrate that the alloy rolled at 780 degrees C (with a rolling reduction of 90%) exhibits remarkable improvement in overall properties after short-time annealing. Microstructural and mechanical analyses reveal that increasing the annealing temperature promotes grain regrowth within the copper matrix and enhances recrystallization, thereby strengthening the alloy's performance. Furthermore, subsequent aging treatment reduces dislocation density and defects in the alloy while diminishing electron scattering barriers, leading to optimized electrical conductivity.
10.1007-s11665-025-12053-0	8	hot; deformation; strain; strain rate; dynamic; hot deformation; recrystallization; dynamic recrystallization; flow; rate; flow stress; compression; constitutive; degrees; stress	The time-dependent anelastic flow of metallic materials after bulk forming dominated by severe plastic compressive deformation leads to a time-dependent effect in springback. The strain hardening and strain softening behavior during severe plastic compressive deformation, as well as the materials' anisotropy, affects the anelastic flow behavior of the material in the unloading process. Hot-rolled copper alloy plates were used as the study object in this paper. The cylindrical samples taken from different directions (rolling direction, short-thickness direction, transverse direction, 45 degrees direction) of the hot-rolled plates were subjected to quasi-state severe plastic single-pass compressive deformation. The anelastic flow behavior in strain hardening and strain softening stage of the severe plastic deformation process was analyzed. The springback behavior during the unloading and standing processes after the severe plastic compressive deformation was revealed. On the basis of the characteristics of the time-dependent anelastic strain flow model and the severe plastic compressive deformation, the time-dependent springback model of the severe plastic compressive deformation was established. The saturated springback amount after the severe plastic compressive deformation was predicted, and the predication results were compared with experimental ones. The results and comparison indicated that the springback after the severe plastic compressive deformation has a time-dependent effect, and the time-dependent springback model of the severe plastic compressive deformation proposed in this study can accurately predict the saturated springback after the severe plastic compressive deformation.
10.1007-s11665-025-12201-6	14	strength; properties; conductivity; electrical; mechanical; cu-; grain; mpa; electrical conductivity; aging; precipitation; phase; mechanical properties; tensile; phases	To address the shortcomings of Fe/Cu bimetallic materials, including uneven surface microstructure, low surface hardness, and inadequate friction and wear performance, this study investigates the influence of varying Fe contents on the microstructure and mechanical properties of Fe/Cu bimetallic materials using solid-liquid composite casting technology. Experimental results indicate that with 1.5 wt% Fe, the coarse dendritic structure of the alpha-Cu matrix is refined into equiaxed grains, and the Pb particle distribution becomes more uniform with the size of Pb particles reduced, which decreases the average grain size from 99.1 mu m to 71.7 mu m. This refinement, alongside the precipitation of Fe particles, markedly enhances interfacial shear strength and microhardness, with improvements of 12.35% and 28.63%, respectively. However, at 2.5 wt% Fe, grain coarsening occurs, leading to reduced shear strength and hardness, likely attributed to the formation of coarse dendrites and uneven delta-phase segregation. Friction and wear performance also improves with 1.5 wt% Fe, exhibiting lower coefficient of friction and wear rates, with reductions of 60% and 21% under oil-lubricated and dry friction conditions, respectively, compared to 0 wt% Fe.
10.1007-s11666-013-0028-3	-1		In this work, Cu-0.5Cr-0.05Zr (wt%) samples obtained by the cold spray process were studied regarding the microstructure and the mechanical properties versus several heat treatments. Ultimate tensile strength higher than 600 MPa, yield strength of 570 MPa and Vickers hardness HV0.2 of about 200 were obtained. Comparison of these results with those obtained by forging or vacuum plasma spraying highlighted the ability of the cold spray technique to produce dense Cu-Cr-Zr deposits with low oxygen content, low level of residual stresses and high mechanical properties.
10.1007-s11666-014-0159-1	5	materials; thermal; heat; properties; material; welding; sintering; fusion; strength; laser; heat sink; thermal conductivity; mechanical; sink; manufacturing	This work focuses on the properties of Cu-Ag alloys deposited by a cold spray process. Helium was used as the carrier gas and main gas to reach particles velocity of 823 m/s, which is in the middle range of the deposition window for Cu alloys. A closed loop circuit avoiding costly helium losses was implemented. Thus, deposition efficiency higher than 95%, porosity below 0.1%, and oxygen content below 150 ppm were obtained. The influence of the deposition parameters on microstructure, mechanical properties ( ultimate tensile strength, yield strength, elongation, hardness), and residual stress level in the material was studied. Intensive work hardening mechanisms are involved by comparison with classically forged material allowing a large tailoring of the material's properties through specific heat treating.
10.1007-s11666-015-0294-3	-1		Of the substrate-related factors that will influence splat formation, alloying elements has been little studied. In the present work, we have examined the role of alloying elements in controlling the extent of splashing of plasma-sprayed splats. Splats of copper (Cu) and copper alloyed with Al and Zr were deposited by plasma spray or as free-falling droplets. The splat formation and splat-substrate interfaces were characterized using SEM and FIB. It was found that the presence of aluminium in plasma-sprayed Cu-10% Al increased the portion of favorable disk-shaped splats compared to pure copper. It was also found that the disk-shaped splat proportion of Cu-10% Al at room temperature is nearly identical to that of Cu splat at 300 degrees C, indicating that the addition of Al in the alloy leads to the improvement of splat formation, correlating with the improvement in the interface bonding with the substrate.
10.1007-s11666-017-0603-0	-1		The effect of non-deformable submicron secondphase particles (d = 200-500 nm) on microstructural refinement during cold spray was examined. Using single particle impact testing, two types of splats were fabricated using two different feedstocks: a Cu-0.21wt% O powder containing Cu2O second-phase particles and a single-phase Cu. Microstructural evolution analysis using high-resolution electron backscatter diffraction shows grain refinement occurred at a higher rate in the Cu-0.21wt% O powder. That was due to dynamic recrystallization initiated by particle-stimulated nucleation (PSN). High-strain-rate deformation of cold spray was found to be the key to activate PSN. The present study suggests cold spray is a possible technique to fabricate ultrafine-grained materials by using feedstock containing second-phase particles.
10.1007-s11666-019-00870-4	6	grain; deformation; strain; strength; dislocation; cu-; tensile; size; ecap; grain size; sfe; ductility; hardening; high; stress	This study investigated the effect of strain rate (10(-3)-10/s) on the compressive properties of pure Cu bulk material at room temperature manufactured by cold spray process. Initial microstructural observation confirmed the sizes of ultra-fine grains to be in hundreds of nm, with dynamic recrystallization on deposited particle interfaces, and the average grain size was found to be 3.14m. The compression test at room temperature showed yield strength of 314-368MPa at initial strain rate of 10(-3)-10/s, at a level similar to that of materials produced with the severe plastic deformation process. Meanwhile, during compressive deformation at all strain rates, work hardening occurred first, and a unique deformation behavior of work softening occurred thereafter after a certain strain. Moreover, as strain rates increased, the rates of work hardening and work softening increased simultaneously. The microstructural observation after the compressive deformation confirmed microstructure evolution in all materials, and as the strain rate increased, the average grain size decreased, and a more uniform structure was formed. Based on the above findings, this study discusses the deformation behavior in correlation with the microstructures of the cold-sprayed Cu materials at different strain rates.
10.1007-s11666-019-00887-9	-1		The applications of magnesium-based alloys are often limited by their poor corrosion and wear resistance performance. The aim of this study is to improve the performance of magnesium alloys by using metal-ceramic coatings. Cu-Ni/Al2O3 and Cu-Zn/Al2O3 coatings were deposited by cold spray. Their microstructure, microhardness, tribological, and corrosion behavior were compared with those of Cu-Al2O3 coatings. The results showed that the Cu-Al2O3 coatings exhibited higher microhardness, lower wear rate, and better corrosion resistance than the Mg alloy substrate, but their antifriction performance was not ideal. Adding Ni or Zn to the Cu-Al2O3 coating resulted in a denser coating with lower porosity. Ni increased the microhardness of the Cu-Al2O3 coating but did not improve its antifriction performance or wear resistance, while Zn increased the microhardness, antifriction performance, and wear resistance of the Cu-Al2O3 coating. The corrosion resistance of the Cu-Al2O3 coating was enhanced by adding Ni, which improved the compactness of the coating, in contrast to the addition of Zn, as the rapid corrosion of Zn resulted in formation of loose corrosion products without protective effect. Thus, such modification of Cu-Al2O3 coatings should be based on application requirements.
10.1007-s11666-021-01227-6	-1		Cu-boron nitride nanosheets (BNNSs) composite coating was fabricated by mechanical alloying and then cold spray. The microstructure, mechanical properties and tribological performance of the composite coating were investigated. The addition of BNNSs into Cu leads to a decrease in the deposition efficiency and microhardness of the coating. However, the introduction of BNNSs reduces the coefficient of friction evidently and improves the wear resistance significantly (by 34%) due to the sliding and lubricating effects of the BNNSs. Hence, the Cu-BNNSs composite coatings could be excellent candidates for low friction and high wear-resistance applications.
10.1007-s11666-023-01624-z	-1		Marine biofouling is a worldwide issue that has aroused great concern in scientific community. Herein, a micron-laminated Cu-Al2O3 composite coating was facilely obtained via plasma spraying of Cu/Al2O3 powders to achieve eco-friendly and long-lasting antifouling performance along with superior wear resistance. The microstructure, long-term antifouling performance, and wear behavior of the Cu-Al2O3 coatings as a function of Al2O3 content were systematically investigated. Results indicated that the Cu-Al2O3 coating exhibited controlled slow copper ions leach rate of approximately 5 times lower than that of the Cu coating, promoting eco-friendly and long-lasting antifouling protection. Additionally, the copper ions leach rate from the Cu-Al2O3 coatings decreased as the Al2O3 content increased, which was mainly related to the Cu amount involved in dissolution reaction. Long-term antifouling efficiencies against bacterial survival and algae settlement for the Cu-Al2O3 composite coatings with 32.1-66.2% Al2O3 were higher than 90%. Furthermore, the Cu-Al2O3 coatings exhibited superior wear resistance by the strengthening of Al2O3. Continuous tribolayer containing trapped Al2O3 particles formed on worn surface was responsible for the excellent wear resistance of Cu-Al2O3 coatings. The outstanding comprehensive performance of Cu-Al2O3 coating combining long-lasting and eco-friendly antifouling ability and remarkable wear resistance gives clear insight into its potential applications in marine antifouling field.
10.1007-s11666-023-01655-6	-1		Hot rolling is an emerging post-processing method for improving mechanical properties of cold sprayed materials. However, the effects of hot rolling on cold sprayed materials are not well clarified. Accordingly, hot rolling assisted with heat treatment was conducted to investigate the effects of hot rolling on plastic deformation of cold sprayed copper bulks. The porosity, crystal grains and dislocation density of copper bulks were characterized through scanning electron microscope, electron back-scatter diffraction and transmission electron microscope. The evolution of pores during hot rolling was simulated using finite element analysis. The microhardness, tensile strength and breaking elongation of the bulks were measured to further explore the effects of hot rolling. The results show that the apparent porosity of the copper bulks sharply decreased due to the dynamic generation and healing processes of the pores in hot rolling. The tensile strength of the copper bulks increased significantly due to the evolution of bonding mechanisms and grain sizes of the copper bulks in hot rolling.
10.1007-s11666-024-01783-7	-1		The purpose of this study is to investigate the effect of copper powder oxidation on the deposition efficiency, microstructure, wear and corrosion resistance. The gas-atomized copper powders in the as-received (Cu-Safina and Cu-FST) and oxidized states (Cu-treat, oxidized in air, 25 degrees C for 5 months; Cu-treat1, oxidized at 100 degrees C for 1 h; and Cu-treat2, oxidized at 200 degrees C for 1 h) were used to prepare the coatings by cold gas spray (CGS). XPS analysis detected Cu2O and CuO for all feedstock powders, increasing for oxidized ones. The deposition efficiency and thickness of the coatings followed the order: Cu-Safina > Cu-FST > Cu-treat1 > Cu-treat > Cu-treat2. For oxidized coatings, SEM images showed more defected microstructure, increase in pores, and microcracks. Cu-FST coating showed a sliding wear rate of (0.13 +/- 0.01) x 10(-4) mm(3) N-1 m(-1)), and abrasive wear rate of (3.2 +/- 0.2) x 10(-4) mm(3) N-1 m(-1). Gas-atomized powder coatings showed a better corrosion resistance performance. The electrolyte did not reach the substrate/coating interface for t >= 700 h and the coatings resisted for 2000 h in salt fog tests. However, oxidized coatings showed low corrosion resistance due to the presence of cracks and defects, and the coating/substrate was severely damaged after approximate to 100 h in 3.5wt%NaCl solution.
10.1007-s11666-024-01843-y	-1		Atmospheric plasma-sprayed (APS) copper-nickel-based coatings are commonly used for the prevention of fretting wear of components in aerospace engines. In this study, Cu-Ni alloy was deposited using plasma spraying on different substrate materials such as stainless steel, carbon steel, and aluminum alloy to investigate the influence of the substrate materials as well as the performance (mechanical and tribological behavior) of the coatings. Microstructural studies revealed a homogeneous microstructure with the presence of splats for coatings deposited on each substrate. The porosity and microhardness of coatings deposited on each substrate were found to be within the range of (1.22 +/- 0.27-1.65 +/- 0.33%) and (117 +/- 10-136 +/- 23 HV0.05), respectively. The tribology results also showed an increase in the frictional coefficient for each substrate from 0.41 at 25 degrees to 0.73 at 300 degrees C. However, a steady state was not obtained at 450 degrees C. Similarly, the wear rates of coatings for each substrate increased from 300 to 450 degrees C test conditions, with no significant wear obtained at 25 degrees C. The results showed that the substrate materials had no significant effect on the performance of the coatings, as the thickness, porosity, surface roughness, and microhardness of coatings for each substrate material were comparable with no remarkable difference.
10.1007-s11669-007-9083-0	12	thermodynamic; ternary; phase; data; experimental; equilibria; phase equilibria; liquid; binary; experimental data; calculated; phases; literature; model; calphad	The thermodynamic properties of the binary Cu-Mg system are examined with a focus on equilibria involving the liquid phase, which is described with a four-species association model, incorporating a two-state treatment for the pure component liquids below their respective melting temperatures. The terminal and intermediate crystalline phases are described as substitutional solid solutions, employing two sublattices for the latter. Model parameters are fitted using available experimental data, and the resulting phase diagram is reported over the full range of compositions in the binary system. We also report the associated To curves, indicating the limits of partitionless crystallization and compare these with reports of amorphous solid formation during rapid solidification processing.
10.1007-s11669-007-9244-1	12	thermodynamic; ternary; phase; data; experimental; equilibria; phase equilibria; liquid; binary; experimental data; calculated; phases; literature; model; calphad	Six highly alloyed Cu-Fe-Ni alloys have been processed with different heat treatments and studied by means of electron microprobe and differential thermal analyses. The results are discussed in comparison with an equilibrium phase diagram calculation performed using the CALPHAD (CALculation of PHAse Diagrams) method. An unexpected temperature window for homogenization has been found in the middle of the composition range.
10.1007-s11669-009-9469-2	-1		Abundant diffusion data in binary fcc Cu-Au and fcc Cu-Pt alloys have been assessed to obtain the atomic diffusion mobilities of fcc Cu-Au and fcc Cu-Pt alloys by the CALPHAD method. The obtained mobilities are expressed as functions of compositions and temperatures. Good agreements are obtained from comprehensive comparisons between the calculated and experimentally measured self-diffusion coefficients, impurity diffusion coefficients, tracer diffusion coefficients, interdiffusion coefficients, and concentration curves. Accordingly, the developed mobility parameters, in conjunction with the CALPHAD-type thermodynamic descriptions, can be used to simulate diffusion behaviors at high temperatures. It is believed that the results of this work contribute to the design of a general Cu mobility database.
10.1007-s11669-013-0241-2	-1		Phase equilibria in the Cu-rich corner of the ternary system Cu-Al-Sn have been re-investigated. Final equilibrium microstructures of 20 ternary alloy compositions near Cu3Al were used to refine the ternary phase diagram. The microstructures were characterized using optical microscopy (OM), x-ray diffraction (XRD), electron probe microanalysis and transmission electron microscopy. Isothermal sections at 853, 845, 833, 818, 808, 803 and 773 K have been composed. Vertical sections have been drawn at 2 and 3 at% Sn, showing beta(1) as a stable phase. Three-phase fields (alpha + beta + beta(1)) and (beta + beta(1) + gamma(1)) result from beta -> alpha + beta(1) eutectoid and beta + gamma(1) -> beta(1) peritectoid reactions forming metastable beta(1) in the binary Cu-Al. With the lowering of temperature from 853 to 818 K, these three-phase fields are shifted to lower Sn concentrations, with simultaneous shrinkage and shifting of (beta + beta(1)) two-phase field. The three-phase field (alpha + beta + gamma(1)) resulting from the binary reaction beta -> alpha + gamma(1) shifts to higher Sn contents, with associated shrinkage of the beta field, with decreasing temperature. With further reduction of temperature, a new ternary invariant reaction beta + beta(1) -> alpha + gamma(1) is observed at similar to 813 K. The beta disappears completely at 803 K, giving rise to the three-phase field (alpha + beta(1) + gamma(1)). Some general guidelines on the role of ternary additions (M) on the stability of the ordered beta(1) phase are obtained by comparing the results of this study with data in the literature on other systems in the systems group Cu-Al-M.
10.1007-s11669-013-0257-7	12	thermodynamic; ternary; phase; data; experimental; equilibria; phase equilibria; liquid; binary; experimental data; calculated; phases; literature; model; calphad	The phase equilibria in the Cu-Fe-Zr ternary system was experimentally investigated by optical microscopy, electron probe micro-analyzer and x-ray diffraction on the equilibriated alloys. Three isothermal sections of the Cu-Fe-Zr ternary system at 1000, 1100 and 1200 A degrees C were experimentally determined, and no ternary compound was found in this system. The further result in the present work shows that the Fe23Zr6 phase in the Cu-Fe-Zr ternary system is an equilibrium phase rather than oxygen-stabilized phase.
10.1007-s11669-014-0305-y	12	thermodynamic; ternary; phase; data; experimental; equilibria; phase equilibria; liquid; binary; experimental data; calculated; phases; literature; model; calphad	Standard enthalpies of formation of ternary phases in the Cu-Ni-Sn system were determined along sections at 25, 41 and 45.5 at% Sn applying tin solution drop calorimetry. Generally, the interaction of Ni with Sn is much stronger than that of Cu with Sn. Along all sections the enthalpy of formation changes almost linearly with the mutual substitution of Cu and Ni within the respective homogeneity ranges. Thus no additional ternary interaction promoting the formation of further Cu-Ni-Sn phases can be assumed. The results are discussed and compared with literature values relevant to this system.
10.1007-s11669-014-0349-z	12	thermodynamic; ternary; phase; data; experimental; equilibria; phase equilibria; liquid; binary; experimental data; calculated; phases; literature; model; calphad	The phase equilibria in the Cu-Fe-Ta ternary system at 1000, 1100 and 1200 C have been experimentally determined by optical microscopy, electron probe micro-analyzer and x-ray diffraction on ternary equilibrated alloys. The Cu-Ta binary system was reassessed and the thermodynamic assessments of the Cu-Fe-Ta ternary system were carried out by using calculation of phase diagrams method on the basis of the experimental data investigated in the present work. A consistent set of the thermodynamic parameters leading to reasonable agreement between the calculated results and experimental data was obtained in the Cu-Ta and Cu-Fe-Ta systems.
10.1007-s11669-015-0404-4	12	thermodynamic; ternary; phase; data; experimental; equilibria; phase equilibria; liquid; binary; experimental data; calculated; phases; literature; model; calphad	By means of the solid-solid diffusion couples together with the electron probe microanalysis technique and Matano-Kirkaldy method, mole fraction interdiffusion coefficients in fcc Cu-Ag-Al alloys at 1073 K were measured. Based on the experimentally determined mole fraction interdiffusion coefficients as well as thermodynamic description of fcc phase, atomic mobilities of Ag, Al and Cu in fcc Cu-Ag-Al alloys were assessed by means of DIffusion-Controlled TRAnsformations software package. The calculated interdiffusivities based on the assessed atomic mobilities agree well with all the experimental data. The reliability of the presently obtained atomic mobilities was further verified by comprehensive comparisons between various model-predicted diffusion properties and the experimental data, including concentration profiles, interdiffusion fluxes and diffusion paths.
10.1007-s11669-016-0459-x	12	thermodynamic; ternary; phase; data; experimental; equilibria; phase equilibria; liquid; binary; experimental data; calculated; phases; literature; model; calphad	The phase equilibria of the Cu-Nb-Zr ternary system at 900, 1000 and 1100 A degrees C were experimentally investigated by optical microscopy and electron probe microanalysis on the equilibrated alloys. Combined with the obtained experimental results, the phase equilibria of Cu-Nb-Zr ternary system were thermodynamically optimized using the CALPHAD (calculation of phase diagrams) method. The Gibbs free energies of the phases in the present work were described by appropriate models. A consistent set of the thermodynamic parameters leading to reasonable agreement between the calculated data and experimental results was obtained in the Cu-Nb-Zr ternary system.
10.1007-s11669-016-0477-8	12	thermodynamic; ternary; phase; data; experimental; equilibria; phase equilibria; liquid; binary; experimental data; calculated; phases; literature; model; calphad	Phase equilibria of the Cu-Sn-Bi ternary system have been investigated by means of x-ray diffraction, scanning electron microscopy and energy-dispersive spectrometry analysis. Cu-Sn-Bi alloys were prepared and equilibrated at 250, 450 and 700 A degrees C, and the equilibrium phases were experimentally identified. Isothermal sections at these three temperatures were proposed based on the experimental results and the information on the three constituent binary systems. Moreover, the solubility of the Bi in the Cu-Sn compounds is less than 0.8 at%. No ternary compound was found. The phase equilibria between the liquid and the solid phases appears to be inclined towards the Bi-corner at all temperatures.
10.1007-s11669-017-0522-2	12	thermodynamic; ternary; phase; data; experimental; equilibria; phase equilibria; liquid; binary; experimental data; calculated; phases; literature; model; calphad	The Cu-Zr binary system is re-investigated via experiment and thermodynamic modeling. Four alloys were prepared by arc melting in order to check the controversial phase equilibria reported in the literature. Both as-cast and annealed alloys were examined by optical microscopy, x-ray diffraction and electron probe microanalysis, and the phase transformation temperatures were measured by differential scanning calorimetry. The intermetallic compounds, Cu24Zr13, Cu2Zr and Cu5Zr8, were demonstrated to be not the stable phases. Based on the literature information and present experimental data, the Cu-Zr system was critically evaluated by means of CALculation of PHAse Diagram approach . A set of self-consistent thermodynamic parameters was obtained, and the calculated phase diagram and thermodynamic properties are in a satisfactory agreement with the experimental data.
10.1007-s11669-017-0538-7	-1		Cu-In-Sn alloys are among the suggested materials to replace Pb-Sn alloys traditionally used in joining processes by the electronic industry. Thorough thermodynamic understanding is required for the selection/design of adequate and efficient alloys for specific applications. Understanding the effects that high cost elements such as In have on microstructure and phase stability is imperative for industrial use. In this work ternary alloys were prepared by melting high purity elements (5N) for selected compositions of the 17 at% Cu isopleth, and cooling down to reproduce process conditions. Chemical composition was determined using scanning electron microscopy equipped with electron probe microanalysis. Measurements of transition temperatures were done by heat-flux differential scanning calorimetry. We present a comprehensive comparison between our experimental results and phase diagram calculations using Liu et al (J Electron Mater 30:1093, 2001) thermodynamic description based in the CALPHAD method, available in the literature.
10.1007-s11669-017-0591-2	12	thermodynamic; ternary; phase; data; experimental; equilibria; phase equilibria; liquid; binary; experimental data; calculated; phases; literature; model; calphad	Through alloy sampling approach, phase equilibria in the Cu-Co-Zr ternary system have been determined. Based on the phases identified with electron probe microanalysis and x-ray diffraction, isothermal sections at both 873 and 1200 K were constructed. No ternary compound was detected. It is evident that remarkable ternary solubility occurs in almost all binary intermetallic phases at both temperatures. For instance, solubility of Co in Cu51Zr14 can be up to 17.6 and 27.5 at% at 873 and 1200 K, respectively. Besides, continuous dissolution between CuZr and CoZr at 1200 K was observed, and the maximum content of Cu in CoZr at 873 K reaches to 42.5 at%.
10.1007-s11669-017-0604-1	12	thermodynamic; ternary; phase; data; experimental; equilibria; phase equilibria; liquid; binary; experimental data; calculated; phases; literature; model; calphad	Phase equilibria of the Cu-Mo-Ti ternary system at 800 and 900 degrees C have been experimentally investigated using electron probe microanalysis and x-ray diffraction analysis. A ternary intermetallic compound (tau phase) was newly found, exhibiting a homogeneity range at both 800 and 900 degrees C. Furthermore, the nominal as-cast alloys Cu50Mo10Ti40, Cu30Mo30Ti40, Cu15Mo50Ti35, Cu40Mo30Ti30, Cu15Mo20Ti65, Cu15Mo30Ti55, Cu15Mo25Ti60, Cu40Mo10Ti50, and Cu60Mo5Ti35 presented a common separated microscopic morphology because of the ternary extent of the Cu-Mo binary liquid phase separation. The newly determined phase equilibria may provide essential information to support thermodynamic assessment and development of Cu-Mo-based alloys.
10.1007-s11669-018-0670-z	12	thermodynamic; ternary; phase; data; experimental; equilibria; phase equilibria; liquid; binary; experimental data; calculated; phases; literature; model; calphad	All phase equilibria and thermodynamic data available in the literature on the copper sulfides high- and low-temperature chalcocite, djurleite and anilite have been critically analyzed for optimization of the solid-state phase diagram of the Cu-S system at 1bar total pressure. A two-sublattice approach derived from a recently developed Gibbs energy model for digenite enables the consideration of the solid solution nature of both modifications of chalcocite and for the first time of djurleite. Anilite is considered as stoichiometric compound. The sulfur solubility of metallic copper is described by a substitutional approach . The obtained Gibbs energy functions for high- and low-temperature chalcocite, djurleite, anilite and copper alloy phase allow computations and predictions of phase equilibria and thermodynamic properties in good accordance with experimental data of the Cu-S solid-state system.
10.1007-s11669-018-0682-8	12	thermodynamic; ternary; phase; data; experimental; equilibria; phase equilibria; liquid; binary; experimental data; calculated; phases; literature; model; calphad	A new formalism recently developed by Belova et al, based on linear response theory combined with the Boltzmann-Matano method, allows determination of tracer and interdiffusion coefficients simultaneously from a single, isotope-free, traditional diffusion couple experiment. An experimental methodology with an analytical approach based on the new formalism has been carried out using the model Cu-Ni system to effectively determine tracer diffusion coefficients from an isotope-free diffusion couple experiment. Cu thin films were deposited in between several binary diffusion couples with varying terminal alloy compositions (Cu-25Ni, Cu-50Ni, Cu-75Ni, Ni). Diffusion couples were annealed at 800, 900 and 1000 degrees C, and the superimposed concentration profiles of thin film and interdiffusion were analyzed for the simultaneous determination of tracer and interdiffusion coefficients. Processed concentration profiles obtained from the diffusion experiments were also fitted with simple Gaussian distribution function. Results were compared to existing literature data obtained independently by radiotracer experiments, and an excellent agreement has been observed.
10.1007-s11669-021-00866-0	12	thermodynamic; ternary; phase; data; experimental; equilibria; phase equilibria; liquid; binary; experimental data; calculated; phases; literature; model; calphad	The phase equilibria of the Cu-Nb-Ni system were investigated via a combination of key equilibrated alloys and thermodynamic modeling. Twelve different compositions of ternary alloys were prepared to determine the isothermal sections at 700, 800 and 900 degrees C, by means of x-ray diffraction and scanning electron microscopy with energy dispersive x-ray spectroscopy. The three- and two-phase regions were determined. The solubilities of the NbNi3 and Nb7Ni6 phases were measured. No ternary compound was found in this ternary system. Based on the experimental equilibria data from the literature and the present work, a thermodynamic description of the Cu-Nb-Ni system was carried out by using the CALPHAD (CALculation of PHAse Diagrams) method. The substitutional model and sublattice model were employed to describe the solution phases and intermediate phases, respectively. A set of self-consistent thermodynamic parameters of the Cu-Nb-Ni system was conclusively obtained. Most of the reliable experimental data were reproduced by the present thermodynamic modeling.
10.1007-s11669-021-00898-6	12	thermodynamic; ternary; phase; data; experimental; equilibria; phase equilibria; liquid; binary; experimental data; calculated; phases; literature; model; calphad	A database to calculate the thermodynamic properties of the liquid quinary Cu-Hf-Ni-Ti-Zr glass forming alloys is developed in the framework of the CALPHAD method. The thermodynamic properties of liquid alloys are modeled using the associate solution model. The thermodynamic properties of three-, four- and five-component liquid alloys of the Cu-Hf-Ni-Ti-Zr system are calculated for a wide composition range. Particular attention is paid to alloys of equiatomic composition, including high-entropy CuHfNiTiZr alloy. The interplay of the ideal and excess contributions to the Gibbs energy of mixing for multicomponent liquid alloys is analyzed, and their role in the thermodynamic stability of the liquid phase is discussed. The amorphization ranges in quaternary and quinary systems are predicted by considering a total molar fraction of associates in liquid alloys. It is shown that equiatomic CuHfNiTiZr liquid falls into the predicted amorphization space. The predicted amorphization ranges for quaternary and quinary systems agree well with available experimental data.
10.1007-s11669-022-00988-z	12	thermodynamic; ternary; phase; data; experimental; equilibria; phase equilibria; liquid; binary; experimental data; calculated; phases; literature; model; calphad	Thermodynamic modeling of the Cu-Fe-S liquid solution is carried in the framework of the modified quasichemical model. The manifold nature of Cu-Fe-S liquid solutions from highly metallic via sulfur-rich to pure liquid sulfur is described by one single Gibbs energy expression at 1 bar total pressure. The model predictive ability of an asymmetric versus symmetric approach is thermodynamically analyzed with respect to the extrapolation scheme from the binary subsystems into the ternary system. Without the need of adjustable ternary parameters predictions of sulfur potentials for the liquid phase are in line with experimental data available in the literature. High-temperature pyrrhotite optimized via the compound energy formalism and Cu-Fe-S alloy phases are taken into consideration to predict phase equilibria with the liquid solution. Four isothermal and four isoplethal sections demonstrate promising agreement between a large stock of experimental data and prediction.
10.1007-s11669-023-01032-4	12	thermodynamic; ternary; phase; data; experimental; equilibria; phase equilibria; liquid; binary; experimental data; calculated; phases; literature; model; calphad	The experimental and thermodynamic descriptions of the Cu-Se-Te ternary system are important in designing alloys for thermoelectric applications. However, information on the Cu-Se-Te ternary system is still lacking in the literature. This study determines the phase equilibria in the isothermal section at 500 degrees C and liquidus projection of the Cu-Se-Te system by using an experimental and Calphad-approach (Calculation of Phase Diagrams). The isothermal section is determined based on the equilibrated alloys. The liquidus projection is determined based on the results of the primary solidification phase of various Cu-Se-Te alloys in the as-cast condition. Two ternary phases, Cu5Se7Te3 and Cu6Se2Te2, are found. The Calphad-approach is used for thermodynamic modeling of the Cu-Se-Te ternary system by employing thermodynamic descriptions of the three constituent binary systems and the experimental results of the isothermal section and liquidus projection. Very good agreement was obtained between the experiment and calculation.
10.1007-s11669-023-01061-z	-1		Phase equilibria were investigated between 200 and 800 degrees C in the Cu-Zn binary system. Wavelength dispersive spectroscopy (WDS) was performed to determine the equilibrium compositions, and differential scanning calorimetry (DSC) was performed to investigate the solidus and liquidus temperatures and the invariant reaction temperatures of the Zn-rich portion. The beta/(alpha + beta) boundary in the Cu-rich portion extended toward the Cu-rich side as the temperature decreased below the A2-B2 order-disorder transformation temperature, and the phase boundaries of the gamma, delta and epsilon phases shifted toward the Cu-rich side. The liquidus temperatures of the epsilon + liquid were higher than those of the previous report. From the experimental results, the phase diagram of the Cu-Zn binary system was determined in the whole composition range.
10.1007-s11669-024-01120-z	12	thermodynamic; ternary; phase; data; experimental; equilibria; phase equilibria; liquid; binary; experimental data; calculated; phases; literature; model; calphad	Ternary alloys samples with 22, 25 and 23 different compositions were prepared for determining isothermal sections at 1123, 1223 and 1373 K, respectively. The microstructures, phase constituents and phase compositions of the annealed Cu-Nb-Ni alloys were analyzed by scanning electron microscopy (SEM) with energy dispersive spectroscopy (EDS) and x-ray diffraction (XRD) methods. Two three-phase regions, fcc+NbNi3+Nb7Ni6, fcc + bcc(Nb) +Nb7Ni6, and three two-phase regions, fcc+NbNi3,Nb7Ni6+NbNi3 fcc + Nb7Ni6, are determined for isothermal sections at 1123 and 1223 K. Two three-phase regions, liquid+NbNi3+Nb7Ni6, liquid + bcc(Nb) + Nb7Ni6, and three two-phase regions, fcc+NbNi3,Nb7Ni6+NbNi3, liquid + Nb7Ni6, are determined for isothermal sections at 1373 K. The solubilities of Cu in NbNi3 and Nb7Ni6 were determined to be similar to 9.6 at% and similar to 11.4 at% at 1123 K, similar to 10.8 at% and similar to 12.4 at% at 1223 K and similar to 11.2 at% and similar to 12.8 at% at 1373 K, respectively. No ternary compounds were found. Based on the experimental phase equilibria data from the literature and the present work, a thermodynamic description of the Cu-Nb-Ni system was carried out by CALPHAD method. The substitutional solution model and sublattice model were employed to describe the solution phases and intermediate phases, respectively. A set of self-consistent thermodynamic parameters of the Cu-Nb-Ni system was conclusively obtained. Most of the reliable experimental data were reproduced by the present thermodynamic modeling.
10.1007-s11669-025-01186-3	12	thermodynamic; ternary; phase; data; experimental; equilibria; phase equilibria; liquid; binary; experimental data; calculated; phases; literature; model; calphad	The experimental data of the enthalpy of mixing and excess entropy of mixing of binary subsystems Cu-Fe, Fe-Ti, and Cu-Ti of Cu-Fe-Ti ternary liquid alloy were utilized to compute the exponential temperature-dependent interaction energy parameters for excess Gibbs energy of mixing using the Redlich-Kister (R-K) polynomial. The optimized parameters were utilized to calculate the excess Gibbs energy of mixing, enthalpy of mixing, and activity of components in the binary and ternary alloys at temperatures of 1873, 1973, 2073, and 2173 K. The Butler equation was utilized to analyze surface properties, while the Kaptay equation was employed to calculate the viscosity of ternary liquid alloys. The computed values of excess Gibbs energy of mixing, enthalpy of mixing, and activity of components in the binary liquid alloys are in good agreement with the experimental data. The surface tension and viscosity of the ternary alloys are highly influenced by the fluctuations in the bulk amount of Cu. As temperature increases, the surface tension of the ternary alloy decreases in a linear manner, while the viscosity decreases in a non-linear way.
10.1007-s11771-010-0545-x	-1		In order to predict and control the properties of Cu-Cr-Sn-Zn alloy, a model of aging processes via an artificial neural network (ANN) method to map the non-linear relationship between parameters of aging process and the hardness and electrical conductivity properties of the Cu-Cr-Sn-Zn alloy was set up. The results show that the ANN model is a very useful and accurate tool for the property analysis and prediction of aging Cu-Cr-Sn-Zn alloy. Aged at 470-510 A degrees C for 4-1 h, the optimal combinations of hardness 110-117 (HV) and electrical conductivity 40.6-37.7 S/m are available respectively.
10.1007-s11771-012-0966-9	-1		Nanoporous copper with nano-scale pore size was synthesized by dealloying Mn-Cu precursor alloy using a free corrosion method. The effects of heat treatment of Mn-Cu precursors on alloy phase, morphology and composition of the resultant nanoporous copper were investigated. It is revealed that the compositions distribute homogeneously in the bulk Mn-Cu precursors, which consequently results in a more fully dealloying for forming nanoporous copper. The alloy phase changes from Cu0.49Mn0.51 and Cu0.21Mn0.79 of non-thermally treated precursor to Cu0.33Mn0.67 of heat treated alloy. The residual Mn content in nanoporous copper is decreased from 12.97% to 2.04% (molar fraction) made from the precursor without and with 95 h heat treatment. The typical pore shape of nanoporous copper prepared by dealloying the precursor without the heat treatment is divided into two different zones: the uniform bi-continuous structure zone and the blurry or no pore structure zone. Nanoporous copper is of a uniform sponge-like morphology made from the heat-treated precursor, and the average ligament diameter is 40 nm, far smaller than that from the non-thermally treated precursor, in which the average ligament diameter is estimated to be about 70 nm.
10.1007-s11771-013-1595-7	11	glass; bulk; metallic; bulk metallic; gfa; bmg; glassy; metallic glass; ability; bulk metallic glass; amorphous; addition; crystallization; mm; glass-forming	Cu46Zr46Al4.8Ti3.2 bulk metallic glass (BMG) was successfully synthesized by copper-mold casting and the mechanical properties at room temperature were measured by compression tests. The structure and thermal characteristics were analyzed by XRD and DSC, and the fracture surface morphology was examined by SEM. The glassy alloy with 4 mm in diameter shows an high fracture strength of 1 960 MPa, with an improvement of about 20% compared to the ultimate compression fracture strength of the Cu46Zr46Al8 BMG, which suggests that the Ti addition improves the compression fracture strength . The different degrees of the adiabatic heating induce four types of fracture features: a vein-like structure, an elongated and striated vein pattern, melting and smooth regions. The elongated and striated vein patterns as well as the melting region show that enormous strain energy is released, which causes significant adiabatic heating. Furthermore, many micro-cracks observed in the smooth region are caused by the strong shear force. In addition, the strong shear force leads to many shear bands as well as the melting in the lateral surface.
10.1007-s11771-017-3689-0	-1		In order to study the effect of Zr on the microstructure and isothermal annealing performance of Cu-Cr in situ composites, Cu-15Cr and Cu-15Cr-0.24Zr alloys were prepared by means of vacuum medium frequency induction melting technology. The two kinds of test alloys with deformation of 3.79 were subjected to isothermal annealing test. The effects of Zr on the as-cast microstructure, the isothermal annealing structure and the tensile fracture morphology of Cu-15Cr alloy were studied by means of scanning electron microscopy (SEM), energy dispersive spectroscopy (EDS) and transmission electron microscopy (TEM). The results show that the addition of Zr leads to the formation of homogeneous and fine CuZr intermetallic compounds, which suppresses the formation electron microscopy of eutectic Cr phase and makes the eutectic Cr content much lower than that of Cu-15Cr alloy. The recrystallization temperature of the Cu matrix is increased, and it is maintained at a fine equiaxed crystal at 400 A degrees C. After isothermal annealing at 400 A degrees C for 220 h, the tensile strength, electrical conductivity and elongation of the test alloy containing Zr were 720 MPa, 68% IACS and 6.7%, respectively; while the tensile strength, electrical conductivity and elongation of the test alloys without Zr were 488 MPa, 70% IACS and 12.4%, respectively.
10.1007-s11771-018-3780-1	2	corrosion; surface; film; electrochemical; films; spectroscopy; layer; current; solution; potential; resistance; composition; x-ray; ions; showed	Effects of nickel component, thiourea, glue and chloride ions and their interactions on the passivation of copper-nickel based alloy scrap anodes were investigated by combining conventional electrochemical techniques. Results obtained from chronopotentiometry and linear voltammetry curves showed that the Ni component made electrochemical stability of the anode strong and difficult to be corroded, caused by the adsorption of generated Cu2O, NiO or copper powder to the anode surface. The Ni-2 vertical bar reducing Cu2+ to Cu+ or copper powder aggravated the anode passivation. In a certain range of the glue concentration <= 8x10(-6) or thiourea concentration <= 4x10(-6), the increase of glue or thiourea concentration increases the anode passivation time. Over this range, glue and thiourea played an adverse effect. The increase of chloride ions concentration led to the increase in passivation time.
10.1007-s11771-019-4199-z	17	wear; composites; coating; friction; composite; coatings; surface; tribological; properties; wear resistance; resistance; powder; sliding; matrix; wear rate	The tribological behaviors of Cu-15Ni-8Sn/graphite composites with the graphite content of 38 vol.% against AISI321 stainless steel under dry-sliding, deionized water and sea water were investigated on a block-on-ring configuration. The results indicated that the friction coefficient was the lowest under dry-sliding, and the highest in deionized water. The wear rate decreased to reach the minimum value of 1.39x10-(15) m(3)/(Nm) in sea water and in deionized water, it increased to the maximum value of 5.56x10-(15) m(3)/(Nm). The deionized water hindered the formation of tribo-oxide layer and lubricating film, which resulted in the largest friction coefficient and wear rate. In sea water, however, the corrosion products comprised of oxides, hydroxides and chlorides were found on the worn surface, and the compacted layer composed of corrosion products and graphite played an important role in keeping the excellent wear resistance. It was elucidated that the tribological behaviors of Cu-15Ni-8Sn/graphite composite were powerful influenced by the friction environments.
10.1007-s11771-019-4200-x	-1		Copper alloyed with various compositions of nickel and tin were cast into molds under argon atmosphere. The cast rods were homogenized, solution heat treated, followed by aging for different time duration. The specimens were characterized for microstructure and tested for microhardness and wear rate. A hybrid model with a linear function and radial basis function was developed to analyze the influence of nickel, tin, and aging time on the microhardness and tribological behavior of copper-nickel-sin alloy system. The results indicate that increase in the composition of nickel and tin increases the microhardness and decreases the wear rate of the alloy. The increase in the concentration of nickel and tin decreases the peak aging time of the alloy system.
10.1007-s11771-020-4297-y	-1		Wear behaviors of a peak-aged Cu-15Ni-8Sn alloy fabricated by powder metallurgy were investigated. The results indicated that the friction coefficients and the wear rates of Cu-15Ni-8Sn alloy within a normal load range of 50-700 N and a sliding speed range of 0.05-2.58 m/s were less than 0.14 and 2.8x10(-6) mm(3)/mm, respectively. Stribeck-like curve and wear map were developed to describe the oil-lubrication mechanism and wear behavior. The equation of the dividing line between zones of safe and unsafe wear life was determined. Lubricating oil was squeezed into micro-cracks under severe wear conditions. In addition, the lubricating oil reacted with Cu-15Ni-8Sn alloy to generate the corresponding sulfides, which hindered the repair of micro-cracks, promoted cracks growth, and led to delamination. This work has established guidelines for the application of the Cu-15Ni-8Sn alloy under oil-lubricated conditions through developing wear map.
10.1007-s11771-020-4356-4	-1		The ultra-high strength Cu-20Ni-20Mn alloy was prepared by vacuum melting and its mechanical property and corrosion behavior were investigated. After thermomechanical treatment, the alloy exhibited an ultra-high tensile strength of 1204 MPa and the applicable elongation of up to 6.2%. With the increasing exposure time in 3.5% NaCl solution, the corrosion current of the alloy decreased, while the polarization resistance and the charge-transfer resistance of the corrosion surface increased. The corrosion products formed on the surface of the alloy exposed for 1 d, and further corrosion made the corrosion product layer much dense, increasing the corrosion resistance and protecting the alloy from further corrosion.
10.1007-s11803-025-2342-4	3	sma; shape; shape memory; memory; smas; superelastic; bars; damping; cu-al-mn; mechanical; bending; applications; numerical; sma bars; material	Shape memory alloy (SMA) bars are currently preferred over elastomeric seismic isolators due to the elimination of degradation within effective damping and stiffness factors during the cyclic response of an isolation system. These bars could also be used to prevent the functionality of the isolator units from failing due to large deformations. This study aims to investigate the performance of a high damping rubber bearing (HDRB) isolator that is combined with two different types of SMA bars, i.e., Nickel-Titanium (Ni-Ti) and Copper-Aluminum-Beryllium (Cu-Al-Be), subjected to near-fault ground motions that are characterized with forward directivity and fling step effects. To achieve this objective, a self-centering material with flag-shape, force-deformation hysteresis was utilized to simulate the behavior of SMA bars in OpenSees. A single degree of freedom (SDOF) system representing an isolated one-story shear building was developed to conduct nonlinear analysis under selected ground motions. The SMA bars were introduced as an X-shape within the model and were connected diagonally to the top and bottom of the isolator. Results showed that the HDRB system's hysteretic response under near-fault ground accelerations experiences significant degradation, especially when near-fault motions involve the fling step effect. It was demonstrated that SMA bars effectively reduce large displacement observed in HDRB systems under near-fault earthquakes. Comparing the results of the base-isolated HDRB and SMA-HDRB subjected to selected ground motions demonstrated that maximum displacement was found to be significantly reduced by an average of 79% when SMA bars were used. Incorporating SMA bars with a larger diameter significantly improves the efficiency of SMA HDRB systems, and a reduction in maximum displacements is more pronounced for fling step, near-fault ground motions.
10.1007-s11837-010-0078-7	-1		We hove observed for the first time a separation of copper :from aluminum after fusion by high frequency (300 kHz.) induction in the Cu-14 wt%Al alloy. The mechanical properties and microstructure of the specimen have been investigated. A novel,finding in this study is that Al(2)Cu, AlCu, and Al(4)Cu(9) intermetallic compounds occurred as inter/aver with the sequence Cu/Al(4)Cu(9)/AlCu/Al(2)Cu/Al during the solidification process and e.vhibit an important effect on the mechanical properties.
10.1007-s11837-014-0978-z	-1		It is a new beginning for innovative fundamental and applied science in nanocrystalline materials. Many of the processing and consolidation challenges that have haunted nanocrystalline materials are now more fully understood, opening the doors for bulk nanocrystalline materials and parts to be produced. While challenges remain, recent advances in experimental, computational, and theoretical capability have allowed for bulk specimens that have heretofore been pursued only on a limited basis. This article discusses the methodology for synthesis and consolidation of bulk nanocrystalline materials using mechanical alloying, the alloy development and synthesis process for stabilizing these materials at elevated temperatures, and the physical and mechanical properties of nanocrystalline materials with a focus throughout on nanocrystalline copper and a nanocrystalline Cu-Ta system, consolidated via equal channel angular extrusion, with properties rivaling that of nanocrystalline pure Ta. Moreover, modeling and simulation approaches as well as experimental results for grain growth, grain boundary processes, and deformation mechanisms in nanocrystalline copper are briefly reviewed and discussed. Integrating experiments and computational materials science for synthesizing bulk nanocrystalline materials can bring about the next generation of ultrahigh strength materials for defense and energy applications.
10.1007-s11837-015-1524-3	-1		This article presents, for the first time, evidence of nanocrystalline structure, through direct transmission electron microscopy (TEM) observations, in a Cu-32 wt% Sn alloy that has been made by an age-old, uniquely crafted casting process. This alloy has been used as a metal mirror for centuries. The TEM images also reveal five-sided projections of nano-particles. The convergent beam nano-diffraction patterns obtained from the nano-particles point to the nano-phase being quasicrystalline, a feature that has never before been reported for a copper alloy, although there have been reports of the presence of icosahedral 'clusters' within large unit cell intermetallic phases. This observation has been substantiated by x-ray diffraction, wherein the observed peaks could be indexed to an icosahedral quasi-crystalline phase. The mirror alloy casting has been valued for its high hardness and high reflectance properties, both of which result from its unique internal microstructure that include nano-grains as well as quasi-crystallinity. We further postulate that this microstructure is a consequence of the raw materials used and the manufacturing process, including the choice of mold material. While the alloy consists primarily of copper and tin, impurity elements such as zinc, iron, sulfur, aluminum and nickel are also present, in individual amounts not exceeding one wt%. It is believed that these trace impurities could have influenced the microstructure and, consequently, the properties of the metal mirror alloy.
10.1007-s11837-015-1644-9	-1		Nanocrystalline Cu-3 at% Zr powders with 20 nm average grain size were created with mechanical alloying and their thermal stability was studied from 550-950A degrees C. Annealing drove Zr segregation to the grain boundaries, which led to the formation of amorphous intergranular complexions at higher temperatures. Grain growth was retarded significantly, with 1 week of annealing at 950A degrees C, or 98% of the solidus temperature, only leading to coarsening of the average grain size to 54 nm. The enhanced thermal stability can be connected to both a reduction in grain boundary energy with doping as well as the precipitation of ZrC particles. High mechanical strength is retained even after these aggressive heat treatments, showing that complexion engineering may be a viable path toward the fabrication of bulk nanostructured materials with excellent properties.
10.1007-s11837-016-1899-9	7	irradiation; shear; grain; ta; deformation; size; radiation; voids; nanocrystalline; simulations; similar; void; temperature; irradiated; boundaries	Immiscible Cu-Ta alloys produced by mechanical alloying are currently the subject of intensive research due to their mechanical strength combined with extraordinary structural stability at high temperatures. Previous experimental and simulation studies suggested that grain boundaries (GBs) in Cu-Ta alloys are stabilized by Ta nano-clusters coherent with the Cu matrix. To better understand the stabilization effect of Ta, we performed atomistic computer simulations of GB-cluster interactions in Cu-Ta alloys with various compositions and GB velocities. The study focuses on a single plane GB driven by an applied shear stress due to the shear-coupling effect. The results of the simulations are in close quantitative agreement with the Zener model of GB pinning. This agreement and the large magnitude of the unpinning stress confirm that the structural stability of these alloys is due to the drastically decreased GB mobility rather than a reduction in GB energy. For comparison, we simulated GB motion in a random solid solution. While the latter also reduces the GB mobility, the effect is not as strong as in the presence of Ta clusters. GB motion in the random solution itself induces precipitation of Ta clusters due to short-circuit diffusion of Ta in GBs, suggesting a possible mechanism of cluster formation inside the grains.
10.1007-s11837-017-2364-0	-1		This article discusses morphology, texture and corrosion behavior of electrodeposited Cu-graphene composite coatings on mild steel. This study demonstrates that a metal-graphene composite coating, in which graphene is incorporated into a suitable metal matrix, is an effective way to harness the anti-corrosive potential of graphene in producing anti-corrosive coatings for corrosion-prone materials such as steel. Enhanced corrosion resistance of such metal-graphene coatings can facilitate reductions in the requisite coating thickness and material costs in a given coating application. Cu-graphene composite coatings were electrodeposited from sulfate-based acidic electrolytic baths consisting of uniform dispersions of electrochemically exfoliated graphene. Incorporation of graphene into a Cu matrix promoted finer coating morphology, reduction in crystallite size and a strong < 220 > texture, which subsequently made these composite coatings about 43% more corrosion resistant in 3.5% NaCl when compared to pure Cu coatings. Enhanced corrosion resistance of the composite coatings was indicated by the corrosion potential which increased with the amount of incorporated graphene.
10.1007-s11837-017-2629-7	-1		The effect of two different annealing processes on the microstructure and barrier-forming ability of Cu-Zr alloy films has been investigated. Cu-Zr alloy films were deposited directly onto SiO2/Si substrates via direct current magnetron sputtering and subsequently annealed by the vacuum annealing process (VAP) or rapid annealing process under argon atmosphere at temperatures 350A degrees C, 450A degrees C, and 550A degrees C. Then, the microstructure, interface characteristics, and electrical properties of the samples were measured. After annealing, the samples showed a preferential (111) crystal orientation, independent of the annealing process. After two annealing methods, Zr aggregated at the Cu-Zr/SiO2 interface and no serious interdiffusion occurred between Cu and Si. The leakage current measurements revealed that the samples annealed by VAP show a higher reliability. According to the results, the vacuum annealing has better barrier performance than the rapid annealing when used for the fabrication of Cu-based interconnects.
10.1007-s11837-019-03483-y	15	aging; strength; conductivity; electrical conductivity; electrical; mpa; treatment; strengthening; degrees; cu-; cold; precipitation; tensile strength; tensile; iacs	Cu/SiCP composites with high strength and high conductivity were prepared by in situ carbonization reaction of silicon. The Cu-Si powder and C powder were mechanically mixed, and in situ carbonized at 850 degrees C for 48 h, then oxidation-treated in dry air atmosphere at 650 degrees C for 8 h, followed by reduction-treating in hydrogen atmosphere at 500 degrees C for 90 min. The results showed that some nano-scale and micron-scale SiCp particles as well as a small amount of nano-scale SiO2 formed during fabrication. The tensile strength, yield strength, elongation and conductivity of the hot-extruded composite were 279 MPa, 180 MPa, 22.80% and 91.48% IACS, respectively; and those of the composite treated by cold-rolling with a reduction of 80% and then annealing at 350 degrees C for 30 min were 425 MPa, 403 MPa, 10.85% and 90.15% IACS, respectively.
10.1007-s11837-019-03708-0	-1		Gold-plated copper alloys are used extensively in electrical contacts where diffusional processes are known to cause contact degradation. An in situ transmission electron microscopy (TEM) heating study was carried out to provide fundamental understanding of the aging phenomena in reasonable timescales. Samples to visualize the interface in TEM were prepared by focused ion beam (FIB) microscopy and heated in situ up to 350 degrees C while holding at intermediate temperatures to enable imaging. The grain boundaries in Au coatings, specifically the columnar boundaries, provided rapid pathways for diffusion of Cu all the way to the Au surface. This unequal diffusion created vacancies in Cu which coalesced into Kirkendall voids. This in situ technique has been applied to visualize the diffusion pathways in electroplated and sputtered Au films deposited directly on Cu, as well the role of Ni and NiP as barrier layers for mitigating Cu diffusion.
10.1007-s11837-019-03735-x	-1		Cu-1Cr-0.1Zr (wt%) alloy has been subjected to surface mechanical attrition treatment (SMAT). The strain-induced microstructure evolution, including the grain refinement and extension of the solubility between copper and chromium particles, was examined using transmission electron microscopy and scanning electron microscopy. The results indicated that the presence of dispersed chromium particles in copper facilitated the refinement of coarse-grained copper, as the copper-chromium interface is an effective nucleation site for dislocations and provides barriers to dislocation motion. In addition, a clear furrow structure and cold-welding structure with a long-range intermixing area were observed, suggesting that a process that combines abrasion, fracture, and cold welding plays an important role in the formation of a supersaturated solid solution. Finally, the results demonstrate that SMAT can effectively strengthen Cu-1Cr-0.1Zr (wt%) alloy without drastically reducing its electrical conductivity, obtaining excellent performance in the top similar to 300-mu m layer with tensile strength of 524 MPa and electrical conductivity of 75.8% IACS.
10.1007-s11837-019-03838-5	-1		Changes in the microstructure and mechanical properties of Cu-Ti alloy sheets during cold rolling and subsequent annealing were studied with and without Cu-Ti precipitates in the initial microstructures. Pre-existing Cu-Ti precipitates plastically deformed and severely elongated in the rolling direction via cold rolling, accelerating the formation of a nano-lamellar structure. A mean lamellar boundary spacing of 20 nm was achieved at an equivalent strain of 6.7. Vickers hardness increased with decreasing lamellar boundary spacing. Subsequent annealing after cold rolling clearly enhanced the mechanical properties, and a maximum Vickers hardness value of 443 HV (4.35 GPa) was attained in the sample with pre-existing precipitates strained to 6.7. These results suggest that pre-existing precipitates promote microstructural refinement during heavy cold rolling, and that heavily cold-rolled Cu-Ti alloys exhibit anneal hardening behavior, leading to excellent mechanical properties.
10.1007-s11837-020-04005-x	17	wear; composites; coating; friction; composite; coatings; surface; tribological; properties; wear resistance; resistance; powder; sliding; matrix; wear rate	The CuZrAlTiNiSi high entropy alloy coating (HEAC) was synthesized on T10 substrate using mechanical alloying and vacuum hot-pressing sintering technique. The results show that the final product of as-milled powders is amorphous HEA phase with homogeneous component distribution. The sintered coating is composed of solid solutions and intermetallic compounds. No pores and defects appear in the HEAC surface, suggesting a good consolidation quality. In addition, the HEAC possesses a good interface bonding, mainly owing to the diffusion of Al atoms from coating to substrate. The average microhardness of the coating reaches 927 HV0.2, and is more than 3 times higher than the substrate (281 HV0.2). The high microhardness can be mainly explained by the second phase strengthening effect and solid-solution strengthening. Furthermore, compared with the substrate, the HEAC exhibits excellent wear resistance with lower friction coefficient, reduction of the wear groove depths and widths, fewer wear volumes, and minimum specific wear rate under the same conditions. Moreover, based on the wider passive region and uniform surface corrosion morphology, the HEAC presents a good pitting resistance in seawater solution.
10.1007-s11837-020-04334-x	2	corrosion; surface; film; electrochemical; films; spectroscopy; layer; current; solution; potential; resistance; composition; x-ray; ions; showed	Copper electrorefining is a key part of copper metallurgical processes. The electrolyte is usually purified to prevent the accumulation of impurities and contamination of the cathode. Cyclone electrowinning is a widely applied purification method, but black copper mud that contains arsenic is produced after the process and endangers the environment. With the addition of effective chelators, controllable electroplating can be achieved. In order to investigate their role in electrodeposition, a variety of chelators were selected and applied in this study. LSV, XRD, and SEM were used to characterize Cu-As alloys produced from each test. The effects of chelators on the number and shifting of phase transition zones during the electrodeposition were analyzed.
10.1007-s11837-021-04731-w	8	hot; deformation; strain; strain rate; dynamic; hot deformation; recrystallization; dynamic recrystallization; flow; rate; flow stress; compression; constitutive; degrees; stress	Hot compression deformation behavior of the Cu-0.45Cr-1.0Ni-0.28Si-0.14Co alloy was studied by a thermal-mechanical simulator at strain rates of 0.001-1 s(-1) and deformation temperatures of 700-900 degrees C. The microstructure and texture of the copper alloy after the hot compression deformation were investigated. The results showed that the flow behavior of the Cu-Cr-Ni-Si-Co alloy was significantly affected by the deformation temperature and strain rate. The typical dynamic recrystallization (DRX) occurred at high temperatures and low strain rates, while the typical dynamic recovery (DRV) appeared at low temperatures and high strain rates. When the deformation temperature increased from 700 degrees C to 900 degrees C, a transition from copper and S texture to gross texture was found. The value of hot deformation activation energy (Q) was calculated as 330.87 kJ/mol. The optimized hot deformation parameters for the Cu-Cr-Ni-Si-Co alloy were 800-850 degrees C/0.01-0.1 s(-1).
10.1007-s11837-022-05376-z	-1		Copper is under consideration as the optimum material for both high heat flux applications and high-frequency pulsed magnets. One challenge is that copper has low strength which is problematic to deployment in these applications. One solution is to alloy copper with body center cubic (BCC) elements to improve its mechanical properties. However, the limited solubility of the BCC elements in copper requires high deformation processes to be used in order to manufacture these 3D composites. In this work high-energy ball milling combined with high-pressure torsion was used to manufacture 3D Cu-Nb composites. After the consolidation, the mechanical properties of the composites were measured using micro-and nano-hardness testing at room and elevated temperatures. The results indicated that after 10 turns during the high-pressure torsion consolidation, the mechanical properties of the composites were completely saturated, displaying uniform properties across the manufactured disk. Performing the high-pressure torsion at elevated temperature further improved the consolidation of the disk. The high-temperature nanoindentation also indicated a change in the deformation mechanism between 200 degrees C and 500 degrees C.
10.1007-s11837-022-05445-3	-1		Cu-20Ni-20Mn-xGa (x = 1, 5 wt%) alloys with high strength and elasticity were prepared and tested for corrosion properties in 3.5 wt% NaCl solution. The hardness, tensile strength, elongation, and annual corrosion rate of the Cu-20Ni-20Mn-1 Ga alloy reached 1368 MPa, 442 HV, 8.63%, and 0.0262 mm/year, respectively, while those of Cu-20Ni-20Mn-5 Ga alloy were 1278 MPa, 428 HV, 2.5%, and 0.0119 mm/year, respectively. The excellent mechanical properties were attributed to the nanoscale NiMn phase which can strengthen the copper matrix. In addition to grain refinement, the addition of Ga also reduced the cathodic current. Also, the corrosion products of the two alloys in 3.5 wt% NaCl solution were mainly oxides and chlorides. The Cu-20Ni-20Mn-5 Ga showed better corrosion resistance with more gallium-rich oxides in the corrosion product film to resist corrosion.
10.1007-s11837-022-05469-9	7	irradiation; shear; grain; ta; deformation; size; radiation; voids; nanocrystalline; simulations; similar; void; temperature; irradiated; boundaries	The objective of this study is to determine the effects of coupled deformation and irradiation extremes on Ta phase evolution in Cu-10at%Ta nanocomposite. Heterophase nanocomposites with positive heat of mixing offer exceptional mechanical properties, high temperature performance, and irradiation tolerance. Here, we consider cooperative effects of irradiation and deformation on phase stability using transmission electron microscopy phase mapping during interrupted in situ indentation. Following irradiation-induced dissolution of Ta nanoparticles, deformation-induced Ta nanoparticle nucleation and growth occur along grain boundaries. This result shows promise that irradiation and deformation may be coupled to stabilize or rejuvenate Ta nanoparticles in extreme environments.
10.1007-s11837-022-05538-z	15	aging; strength; conductivity; electrical conductivity; electrical; mpa; treatment; strengthening; degrees; cu-; cold; precipitation; tensile strength; tensile; iacs	Cold-rolled Cu-Ni-Si copper alloys were aged by electropulsing directly without the help of a furnace, and excellent strength and electrical conductivity were achieved. The strength and electrical conductivity reach 815 MPa and 38.9% IACS respectively for the sample aged by electropulsing with the frequency of 200 Hz for 10 min. The maximum electrical conductivity of samples, aged by electropulsing with the frequency of 400 Hz for 10 min, reaches 41.6% IACS. The conductivity of the sample aged at 200-400 Hz for 1 min is more than that of the sample aged by a furnace at 450 degrees C for 10 min. High-density delta-Ni2Si precipitates with size of 1-5 nm are found for the samples aged by electropulsing. Compared to the traditional aging treatment, electropulsing facilitates the diffusion of Ni and Si atoms to accelerate precipitation hardening. Additionally, cold rolling is also beneficial to the nucleation of precipitation and further improves the properties of Cu-Ni-Si alloy. Because electropulsing facilitates recrystallization at 300-500 Hz, this leads to decreased strength of copper alloy.
10.1007-s11837-022-05606-4	-1		The mechanical characteristics of bimodal nanocrystalline (BN) Cu-Ag alloy metallic material are described, using a plasticity model based on dislocation theory. Stress-strain curves are generated for the BN Cu-Ag alloy material after accounting for Orowan strengthening and the dislocation motion of the coarse and fine grain phases. The numerical outcomes demonstrate that the suggested model is capable of describing the mechanical characteristics of the bimodal metal, such as yield strength and strain hardening. The experimental findings and these predictions agree fairly well. The suggested model effectively captures the inherent behavior of the bimodal Cu-Ag alloy for grain size, volume fraction of solute, and strain rate. For the BN Cu-Ag alloy, Orowan strengthening has very little to no impact on the mechanical characteristics.
10.1007-s11837-022-05633-1	-1		The present study focused on the Cu-Pb system and investigating the distribution behaviors of various minor elements through the equilibrationquenching-EPMA analysis experimental technique. Obtained results showed that: (1) An intermetallic compound consisting mainly of Cu-Pb-Se-Te formed below 956 degrees C. (2) As, Sb and Sn had similar distribution behaviors, which mainly entered the solid Cu phase at the temperature range of 500-900 degrees C, but became concentrated in the liquid alloy phase at temperature range of 900- 1060 degrees C, and their distribution ratios increased along with increasing temperature. (3) Bi was mainly found in the liquid alloy phase, and its distribution ratio ranged from 6.8 to 836.5 at the experimental conditions. (4) Se and Te formed an intermetallic alloy phase under 900 degrees C, and they enriched in the liquid alloy phase between 960 degrees C and 1060 degrees C. (5) Au was mainly found in the solid Cu phase at the temperature range of 500-900 degrees C, and its distribution ratio was about 1.5 at 900-1060 degrees C. The distribution ratio of Ag decreased from 8.7 to 2.3 when increasing the temperature from 500 degrees C to 1060 degrees C. Distribution behavior of As, Sb, Bi and Sn is consistent with their interfacial enthalpies with Cu and Pb.
10.1007-s11837-023-05778-7	-1		Copper alloys are often used as a substitute for gold because of their bright gold color and low production cost. Seventeen kinds of Cu-Al alloys, Cu-Zn alloys, and Cu-Sn alloys with different compositions were fabricated to investigate the effect of chemical composition and oxidation treatment on their colors. In addition, machine learning was used to establish the relationship between all alloys' composition and color. The best model for each alloy also had been sought out. More importantly, through the analysis of the calculated results, the tree-structure-based models, gradient boosting regressor, random forest regressor, and decision tree regressor, exhibited a better predictive power on the small data set. Subsequently, Cu-4.17 wt% Al, Cu-24.3 wt% Zn, and Cu-10.1 wt% Sn alloys were selected for oxidation at 100 degrees C, which showed that later oxidation could also change sample color.
10.1007-s11837-023-05810-w	6	grain; deformation; strain; strength; dislocation; cu-; tensile; size; ecap; grain size; sfe; ductility; hardening; high; stress	The deformation mechanism of bimodal nanotwinned (NT) Cu-Ag alloy with grain boundary segregation has been simulated by the molecular dynamics method. The equidistance scaling method has been used to generate a grain boundary affect zone. Construction of a bimodal NT Cu-Ag alloy model was achieved by implanting coarse NT grains in an ultrafine grain matrix. Uniaxial tensile experiments were carried out on NT Cu-Ag alloys to explore the deformation mechanism of Cu-Ag alloys in different strain conditions. By analyzing atomic stress-strain images obtained by uniaxial tensile testing, the strength of the bimodal NT Cu-Ag alloy models has been discovered to have a relationship with the coarse grain size and Ag atom concentration. A detailed description is given based on the dislocation activity and the associated deformation mechanism. The properties of the bimodal NT Cu-Ag alloys have been analyzed by surveying the intrinsic dislocation activity of the models.
10.1007-s11837-023-05848-w	8	hot; deformation; strain; strain rate; dynamic; hot deformation; recrystallization; dynamic recrystallization; flow; rate; flow stress; compression; constitutive; degrees; stress	In this paper, a Cu-3.20Ni-0.61Co-0.75Si-0.19Cr-0.15 Mg (wt%) alloy was subjected to hot compression at temperatures of 700-950 degrees C and strain rates of 0.001-10 s(-1). The constitutive equations were established using a strain-related Arrhenius model and a feed-forward artificial neural network (ANN) model. Evaluation showed that the ANN-type constitutive equation had a high Pearson correlation coefficient of 0.9997 and a low mean squared error of 2.55 MPa2; thus, it was more accurate to describe the flow behavior of the Cu-Ni-Co-Si-Cr-Mg alloy than the strain-related Arrhenius-type constitutive equation. The hot processing maps in the conditions of non-linear dissipation governed by the two constitutive equations were also established. Evaluation showed that the ANN-type hot processing maps successfully predicted unstable deformation and dynamically-recrystallized microstructure and thus had better performance than the Arrhenius-type hot processing maps. The microstructure of the Cu-Ni-Co-Si-Cr-Mg alloy after hot compression was also characterized in detail. The microstructural features were unstable deformation for the compression at 700 degrees C and 0.001 s(-1), uneven deformation for the compression at 700 degrees C and 1 s(-1), equiaxed subgrains for the compression at 950 degrees C and 0.001 s(-1) and equiaxed grains and annealing twins for the compression 950 degrees C and 1 s(-1).
10.1007-s11837-024-06382-z	7	irradiation; shear; grain; ta; deformation; size; radiation; voids; nanocrystalline; simulations; similar; void; temperature; irradiated; boundaries	Amorphous interfacial complexions are particularly resistant to radiation damage and have been primarily studied in alloys with good glass-forming ability, yet recent reports suggest that these features can form even in immiscible alloys such as Cu-Ta under irradiation. In this study, the mechanisms of damage production and annihilation due to primary knock-on atom collisions are investigated for amorphous interphase and grain boundaries in a Cu-Ta alloy using atomistic simulations. Amorphous complexions, in particular amorphous interphase complexions that separate Cu and Ta grains, result in less residual defect damage than their ordered counterparts. Stemming from the nanophase chemical separation in this alloy, the amorphous complexions exhibit a highly heterogeneous distribution of atomic excess volume, as compared to a good glass former like Cu-Zr. Complexion thickness, a tunable structural descriptor, plays a vital role in damage resistance. Thicker interfacial films are more damage-tolerant because they alter the defect production rate due to differences in intrinsic displacement threshold energies during the collision cascade. Overall, the findings of this work highlight the importance of interfacial engineering in enhancing the properties of materials operating in radiation-prone environments and the promise of amorphous complexions as particularly radiation damage-tolerant microstructural features.
10.1007-s11837-024-06443-3	-1		The mechanisms of Cr phase solubility increase and dynamic recrystallization of the Cu matrix in the adiabatic shear band (ASB) of Cu-15Cr in situ composites were, to our knowledge, first investigated in this paper. Quantitative calculations showed that the solubility of Cr phases increased by 0.51 at% and 1.0 at% at the edge and center of the ASB, respectively. Thermodynamic analysis revealed that the free energy difference between the Cr phases and Cu matrix was the thermodynamic condition for the dissolution of the Cr phases. Kinetic analysis showed that the dissolution of Cr phases was the result of combined effects of high dislocation density, high adiabatic temperature, high cooling rate, and additional tensile stress. The adiabatic temperature (660 K) and cooling rate (3000.0 K/s) were higher, and the Cr phase was subjected to greater additional tensile stress in the center than those (temperature: 443 K, cooling rate: 2538.5 K/s) at the edge of the ASB. Hence, the increased solubility of Cr phases in the center of the ASB was higher than that at its edge. Additionally, dynamic recrystallization occurred in the Cu matrix in the center of the ASB, and the evolution mechanism was also analyzed from the thermodynamic-kinetic view.
10.1007-s11837-024-06517-2	-1		Continuous casting processes of metals are the most common in terms of obtaining the input material for metal working processes such as wire drawing. One of the issues regarding the process is maintaining the proper temperature preventing cast rod surface oxidation. Experimental work using a laboratory furnace was conducted to verify the parameters determined using finite element method simulations of continuous casting of CuMg alloys. Furthermore, as the alloys are fully novel and not produced or researched on a large scale, they were subjected to microstructural analysis and basic property tests in order to determine their electrical conductivity, density, hardness, and impact toughness. Additionally, pure copper was cast with the same laboratory furnace and the same parameters to function as a point of reference. The obtained results were also compared to commercial materials used for electrical purposes, such as brasses and bronzes. The obtained results proved that the mechanical properties of tested alloys are 2-2.5 times higher than pure copper. Also, the tested materials exhibit lower densities than commercial brass or bronze alloys and their mechanical properties are similar, while electrical conductivity is significantly higher and, thus, they may be used as a material for electrical applications.
10.1007-s11837-024-06640-0	14	strength; properties; conductivity; electrical; mechanical; cu-; grain; mpa; electrical conductivity; aging; precipitation; phase; mechanical properties; tensile; phases	This study employed molecular dynamics (MD) simulation to investigate the mechanical behavior of copper-silver (Cu-Ag) nanocrystalline alloys with twinning structures under solute gradient polarization conditions. The equidistant scaling method was used to identify different regions within the material, such as the solute concentration distribution from the grain interior to the GBs (GBs). MD simulations revealed that adjusting the twinning boundary spacing (TBS) can effectively improve the mechanical properties of Cu-Ag alloys. Tensile tests showed that stretching the twinning boundaries leads to a reduction in stress levels within the alloy. Furthermore, analysis based on the atomic structure volume fraction revealed that larger TBS values result in more pronounced structural changes within the alloy, particularly a significant transition from the face-centered cubic structure to the hexagonal close-packed structure. The latter typically possesses a higher density and closer packing, thus often exhibiting a higher strength and hardness. These findings reveal that adjusting the grain size, segregation gradients, TBS, and grain number can effectively improve the mechanical properties of Cu-Ag alloys.
10.1007-s11837-024-06818-6	-1		There are currently two commonly used ways to recover copper alloys from waste photovoltaic welding strips, such as acid washing and high-temperature oxidation, during which a large amount of waste gas, waste water, and various oxides will be generated. In this work, a unique approach to recycling waste photovoltaic welding strips is proposed by introducing induction melting of the waste photovoltaic ribbon for designing Cu-Sn-Pb alloys. The microstructure, microhardness, tensile properties, electrochemical performance, and friction of recycled Cu-Sn-Pb alloys from waste photovoltaic welding strips have been investigated. The results show that, with the increase of tin content, the size of the precipitated lead phase increases from 2.2 mu m to 13.6 mu m, the solid-solution-strengthening effect increases, the microhardness of the alloy increases from 113 HV to 146 HV, and the tensile strength increases from 628 MPa to 654 MPa. The existence of brittle phase Cu10Sn3 in the alloys leads to the decrease of the ductility and the acceleration of wear in the friction process. Both 6% Sn and 10% Sn alloys exhibit polarization potentials at approximately-0.14 V. This discovery provides a potential approach to recycling Cu-Sn-Pb alloys from waste photovoltaic welding strips.
10.1007-s11837-025-07292-4	-1		This study investigates the effects of different cerium additions on the properties of Cu-Al-Mn high-temperature shape memory alloy (HTSMA), such as the characteristic martensitic transformation temperatures, transformational kinetic parameters, and martensitic microstructures which are related to its shape memory mechanism and also to its magnetic behavior. Polycrystalline alloys with a base composition of Cu77.32Al21.02Mn1.67 (at%) were synthesized, and varying concentrations of cerium (Ce-1 to Ce-4) were added for comparison. Differential scanning calorimetry tests revealed notable increments in transformation temperatures with cerium additions. Specifically, the austenite start temperature of the reference alloy increased from 143.75 degrees C to 194.88 degrees C by 0.05 at% of Ce addition (Ce-3 alloy), corresponding to the formation of CeCu5 and Mn1.15Cu3.85Ce phases. However, excessive Ce addition in Ce-4 led to the over-stabilization of secondary phases, reducing the transformation temperatures. Microstructural analysis indicated that Ce addition of refined grains changed the crystallite size of the martensite structure and reduced lattice strain (from 0.72% to 0.34%). Magnetic characterization demonstrated that Ce addition shifted the alloy towards paramagnetic behavior, with M-H curves showing no significant coercive field or remanent magnetization across the studied alloy samples. These findings suggest that cerium can enhance the high-temperature performance of Cu-Al-Mn HTSMAs, with potential applications in environments requiring both shape memory and magnetic properties.
10.1007-s11837-025-07470-4	15	aging; strength; conductivity; electrical conductivity; electrical; mpa; treatment; strengthening; degrees; cu-; cold; precipitation; tensile strength; tensile; iacs	Microstructure evolution, mechanical properties and electrical conductivity of Cu-1Cr-0.1Zr alloy in different states during two-stage cryorolling and aging were investigated. Compared to single-stage aging, intermediate aging promotes the emergence of GP zones in the alloy, accelerating the precipitation of high-density nano-precipitates. Because the intermediate aging precipitated phase has a pinning effect, more nano-twins and dislocation pile-ups were produced, which effectively improved the tensile strength of the alloy. The dense dislocations produced by a second cryorolling provide more nucleation sites, which makes precipitated phases fine and uniform and ensures the lower resistivity of the alloy. After the two-stage cryorolling and aging, the alloy has the optimal properties with a tensile strength of 648.5 MPa, an electrical conductivity of 77% IACS and elongation of 9.4%. The energy-saving and time-efficient two-stage cryorolling and aging provide a feasible way to balance the strength and conductivity of Cu-1Cr-0.1Zr alloy.
10.1007-s11837-025-07606-6	14	strength; properties; conductivity; electrical; mechanical; cu-; grain; mpa; electrical conductivity; aging; precipitation; phase; mechanical properties; tensile; phases	This study investigates the effects of Sn addition on the microstructure, precipitation behavior, and the mechanical and electrical properties of Cu-6 wt% Ag alloys. Sn (0.1-2 wt%) was selected for its ability to enhance mechanical strength with minimal impact on electrical conductivity, without increasing the melting difficulty of the alloy. Cu-Ag-Sn alloys were fabricated by induction melting and solidification, then subjected to thermal aging and cold deformation. The incorporation of Sn effectively suppressed discontinuous precipitation (DP) and promoted the formation of finer and more uniformly distributed Ag-rich continuous precipitates (CP), reducing the average interparticle spacing from 219.3 nm to 89.99 nm at 0.5 wt% Sn. At an 80% rolling reduction, the Cu-6 wt% Ag-0.5 wt% Sn alloy exhibited a tensile strength of 535 MPa and a hardness of 173 HV-representing improvements of 10.3% and 11.9%, respectively, over the Sn-free counterpart-while maintaining satisfactory electrical conductivity (63.9% IACS). Notably, the addition of Sn facilitated simultaneous enhancements in both strength and ductility, with fracture strain increasing from 7.3% to 8.7% after aging at 450 degrees C followed by deformation. Mechanistic analysis indicated that precipitation strengthening was the dominant contributor to yield strength, complemented by dislocation hardening, grain boundary strengthening, and solid solution strengthening.
10.1007-s12034-009-0060-6	-1		Discontinuous precipitation (DP) is associated with grain boundary migration in the wake of which alternate plates of the precipitate and the depleted matrix form. Some copper base alloys show DP while others do not. In this paper the misfit strain parameter, eta, has been calculated and predicted that if 100 eta > +/- 0.1, DP is observed. This criterion points to diffusional coherency strain theory to be the operative mechanism for DP.
10.1007-s12034-011-0102-8	16	wear; composite; composites; powders; milling; particles; powder; wt; sliding; friction; hardness; matrix; mechanical; surface; properties	The multiple hardening mechanisms of a copper matrix have been presented and discussed. The pre-alloyed ball milled Cu-3 wt%Al and the atomized Cu-0.6 wt%Ti-2.5 wt%TiB2 powders have been used as starting materials. Dispersoid particles Al2O3 and TiB2 were formed in situ. The powders have been hot consolidated. Optical microscopy, SEM, TEM, and X-ray diffraction analysis were performed for microstructural characterization. Increase in microhardness of Cu-3 wt%Al compacts is a consequence of the crystallite size refinement and the presence of Al2O3 particles. High hardening of Cu-0.6 wt%Ti-2.5 wt%TiB2 is a consequence of the presence of modular structure, Cu4Ti(m), and TiB2 particles.
10.1007-s12034-011-0252-8	2	corrosion; surface; film; electrochemical; films; spectroscopy; layer; current; solution; potential; resistance; composition; x-ray; ions; showed	Tin as an alloying element is of great interest in brasses for dezincification impediment. In this paper, Cu-30Zn-1Sn alloy was submitted to three different heat treatments, viz. A (heating up to 800 A degrees C for 20 h, held at 200 A degrees C for 20 h in salt bath and air cooled), B (heating up to 800 A degrees C for 20 h and water quenched) and C (heating up to 600 A degrees C for 20 h and water quenched). The influence of heat treatment on microstructure was evaluated by OM and SEM-EDS analysis. The corrosion resistance in buffer solution (pH 9), H3BO3/Na2B4O7 center dot 10H(2)O, with various concentrations of chloride ions was evaluated by potentiodynamic polarization curves and compared with multi-component Pourbaix diagrams. A correlation between the heat treatment, microstructure and passivity of the heat treated samples was observed. The results indicated that all heat treatment procedures led to formation of alpha, and gamma-Sn-rich phases as microstructure constituents with a small fraction of beta' phase in A. Sn-rich phase appears in grain boundaries and its morphology was slightly changed due to heat treatment. Beneficial influence of low concentration chloride ions on passivity was associated with the formation of copper oxides/hydroxide and chloride complexes. Deterioration was observed at concentrations higher than 0 center dot 05 M NaCl due to accelerated dissolution of copper by formation of CuCl2-. As a result of dezincification process, preferential corrosion attack and copper redeposition on alpha phase (matrix) were observed. However, Sn-rich (gamma(1)) phase in grain boundaries was not attacked due to SnO2 formation. In buffer solution, the higher passivity current density in A was related to the presence of small amount of beta' phase. On the other hand, in 1 M NaCl, lower critical current density for passivation in B and A (about two times lower than C) was attributed to the grain size effect.
10.1007-s12034-014-0001-x	16	wear; composite; composites; powders; milling; particles; powder; wt; sliding; friction; hardness; matrix; mechanical; surface; properties	Present work deals with the preparation of spark plasma-sintered Cu-Zn aggregate (5, 10 and 20 wt% Zn) with interfacial bonding only starting from elemental powders of Cu and Zn (99.9% purity) and subsequently making of porous template of Cu by dezincification. Sintering is done so as to achieve only interfacial bonding with the aim to maintain maximum potential difference between the Cu and Zn particles during dezincification process in various solutions, viz. 1 N HCL and 3.5 wt% NaCl solutions. X-ray diffraction, optical microscopy and SEM-EDS are carried out to examine microstructural evolution and subsequent changes in hardness with sintering temperatures and different Zn percentages. Dezincification and pore formation are conducted on sintered 0-5 mm thick 12 mm diameter disc samples. The size, distribution and nature of pores in porous templates of Cu are then investigated using optical microscopy and SEM-EDS analysis.
10.1007-s12034-019-1911-4	-1		Binary-shape memory alloys that are based on copper, mainly copper-aluminium, copper-zinc and copper-tin alloys, either with or without ternary elemental additions, are of special interest to the industry and academia because of their good shape recovery, ease of processing, larger recovery strain and lower cost. However, unlike Ni-Ti shape memory alloys, their uses are moderately limited due to shortcomings, such as stabilization of martensite due to ageing, brittleness and low mechanical strength . Therefore, efforts have been made over the years to overcome these limitations using appropriate ternary and quaternary elemental additions. This work takes into account the data obtained from the experimental work carried out by the authors of this paper as well as the data obtained from the experimental and theoretical works carried out by earlier researchers in this area that have been published in the literature over the years. It is observed in quaternary shape memory alloys based on copper that with an increase in the atomic radius of the quaternary element, the hysteresis width is found to increase. With the addition of ternary elements to binary Cu-based alloys (Cu-Al and Cu-Zn), and quaternary elements to ternary Cu-based alloys (Cu-Al-Fe, Cu-Al-Ni, Cu-Al-Mn, Cu-Zn-Al, Cu-Zn-Ni and Cu-Zn-Si), the M-s temperature either increases or decreases. This influence is directly correlated with the e(v)/a ratio and c(v) values. It is also observed that as the concentration of electrons decreases, the Ms temperature decreases too. In addition, in this paper, we have tried to obtain relationships between the M-s temperature and the mass or atomic% of different elements through multiple regressions to generalize the interpretations.
10.1007-s12034-019-1928-8	2	corrosion; surface; film; electrochemical; films; spectroscopy; layer; current; solution; potential; resistance; composition; x-ray; ions; showed	Electrodeposition of a copper-silver alloy based on a 1-butyl-3-methylimidazolium chloride (BMIC) ionic liquid was studied. The electrochemical behaviour of copper and silver ions was characterized by cyclic voltammogram. The morphologies and phase compositions of copper-silver alloy coating under different electrodeposition conditions were investigated by scanning electronmicroscopy and X-ray diffraction. The results show that copper-silver alloys with different micro-morphologies can be obtained under different potential conditions in BMIC. Co-deposition of the copper-silver alloy followed a two-step reduction process, the first step is the reduction of the cupric ion to the cuprous ion and the second step is the simultaneous reduction of the cuprous ion and the silver ion to form an alloy. A dendritic alloy can be obtained at -0.60 V, a bract alloy can be obtained at -0.80 V and a granular alloy can be obtained at -1 V. The coating particle size at 60 degrees C was smaller than the particle size obtained at 40 degrees C. The Cu-Ag alloy prepared by electrodeposition in ionic liquids consists of single-phase copper and single-phase silver.
10.1007-s12034-024-03208-1	-1		Copper-based composites with different quality scores for NbC particle reinforcement were prepared by spark plasma sintering. The microstructure of the copper-based composites with different NbC contents was studied, and the influence of NbC content on the density, electrical conductivity and hardness of the copper-based composites was investigated. The results showed that the electrical conductivity of the Cu-4 wt% NbC composite material after spark plasma sintering was 70.4% IACS (IACS is the percentage of the ratio of the conductivity of the sample to a certain standard value. The annealed copper wire with a density of 8.89 g/cm3, a length of 1 m, a weight of 1 g and a resistance of 0.15328 Ohm is used as this certain standard value), and the hardness was 63.4 HV. The strengthening mechanisms of NbC in copper-based composites were dispersion strengthening and fine crystal strengthening. During the spark plasma sintering process, the Zener pinning of NbC particles slowed grain boundary migration, which effectively prevented the pure copper grains from growing and thus enhanced the pure copper. The proportion of NbC in the raw powder was changed to adjust the proportion of fine crystals, and then the mechanical properties of the material were adjusted. Additionally, NbC caused a preferred orientation of pure copper and reduced some of the stress in the material.
10.1007-s12034-024-03216-1	14	strength; properties; conductivity; electrical; mechanical; cu-; grain; mpa; electrical conductivity; aging; precipitation; phase; mechanical properties; tensile; phases	This study investigates the Martensite transition in Cu-Mn-Al alloys (CMAs) via the use of many methods, including scanning electron microscopy, temperature-dependent X-ray diffraction, resistivity and thermal measurements. The Martensite transition hysteresis and characteristic temperature are primarily determined by the alloy composition, crystal structure and residual stress. Furthermore, these alloys have been reported to have surface and crystallographic characteristics often associated with twinning structures. Resistivity experiments conducted during heating and cooling cycles demonstrate a 2.57-fold increase inside the phase change zone, emphasizing the influence of the transition on electrical conductivity. The Martensite transition temperature may be altered by 110 K by the manipulation of the electron-to-atom ratio (e/a), indicating the high susceptibility of this temperature to changes in chemical composition. Differential scanning calorimetry shows that the transition is accompanied by a maximum entropy shift of 48 J kg-1. K, which offers valuable information on the thermodynamic driving factors involved. This work successfully attains a cooling power of 1350 W, which is equivalent to the cooling power of NiTi wire (1500 W), by using a theoretical manufacturing method and optimizing the CMAs. Overall, this work clarifies the Martensite transition in CMAs, highlighting its impact on their characteristics and indicating their potential for effective thermal energy storage and release applications. It is advisable to further optimize their performance and economic viability by considering the e/a ratio.
10.1007-s12034-025-03444-z	2	corrosion; surface; film; electrochemical; films; spectroscopy; layer; current; solution; potential; resistance; composition; x-ray; ions; showed	Cu-Ni-W thin films were deposited by varying the current density from -5 to -60 mA cm-2 using the galvanostatic chronopotentiogram method on indium tin oxide (ITO) coated glass substrates. X-ray diffraction analysis revealed that Cu-Ni-W thin films exhibited face-centered cubic structures with the presence of specific crystallographic planes, particularly (111), (200) and (220) at 2 theta values of 43.4 degrees, 50.7 degrees and 74.7 degrees, respectively. The additional peaks observed at other 2 theta values correspond to the NiW and Ni4W phases. The scanning electron microscopy micrographs of the films demonstrated a uniform structure characterized by a compact and dense morphology. The surface of the films displayed a metallic lustre attributed to the presence of Cu, Ni and W. The cross-sectional micrographs of the films indicated an average thickness of 1.1 to 1.2 mu m. The energy dispersive X-ray spectroscopy analysis have shown that an increase in deposition current density leads to a rise in the relative concentration of Ni and W within the films, whereas the concentration of Cu decreased. The XPS survey spectrum also confirmed the presence of metallic Cu, Ni and W in the deposits. It was found that film deposited at higher current densities favours the growth of a smaller crystalline size of 17 nm and a higher degree of texture coefficient of 2.48. The maximum micro-strain of approximately 16% was calculated from the peak broadening of the X-ray diffractograms. The strong (111) texture and nano-crystallites as confirmed by XRD, resulted in an outstanding corrosion resistance of 16.22 k Omega-cm2 for the film deposited at -60 mA cm-2.
10.1007-s12043-008-0216-8	9	magnetic; magnetization; magnetoresistance; temperature; superparamagnetic; annealing; gmr; field; magnetic properties; ferromagnetic; granular; samples; magnetic field; melt-spun; particles	SMARTer, a 36-meter small angle neutron scattering (SANS) spectrometer was installed at the Neutron Scattering Laboratory (NSL), National Nuclear Energy Agency of Indonesia-BATAN in Serpong, Indonesia and has performed the experiment for studying the magnetic structures of Cu(NiFe), CuCo and FeSiBNbCu metal alloys. The experiments were conducted at room temperature and up to 1 T (10 kOe) of external magnetic field. At zero fields, isotropic scattering identified as nuclear scattering is dominant. When a magnetic field is applied in a horizontal direction perpendicular to the neutron beam, the response of the magnetic scattering permits extraction of the field-induced re-arrangement of the magnetic moment. With increasing field the distortion is more pronounced and the magnetic scattering dominates the intensity and affects the peak position. Radial and angular averaging from experimental data are given to show the details of magnetic structures.
10.1007-s12043-018-1613-2	-1		Electrical resistivity measurement is an exact way to find defects in metals and alloys. Defects contribute to the residual resistivity, and determining their number is very important. Defining the inner electrical structure of an alloy is difficult, and especially it is unpredictable in alloys. This article offers a genetic programming formulation to learn how deposition conditions and alloy constituents affect the electrical resistivity of Cu-Zn alloy. Input parameters selected were: measurement temperature (K), Cu and Zn% content in the deposition bath and thin films, bath temperature, deposition potential, and the grain size of the samples. Electrical resistivity values were the output parameters. A total of 130 training and testing sets were selected. The comparative results prove the superior performance in predicting electrical resistivity of the films. The produced model proposes a close relationship for all the input parameters with the electrical resistivity property.
10.1007-s12046-018-0943-6	-1		The aim of this investigation is to assess the influence of austempering heat treatment on microstructure, mechanical properties, and wear behavior of copper alloyed AGI. Tensile and wear test samples are prepared from as-cast gray iron. Initially, samples are austenitized and then isothermally austempered at six different temperatures for the constant time period. The resulting microstructures are evaluated and characterized by means of a light microscope, scanning electron microscope (SEM) and X-ray diffraction analysis. The wear test is carried out using a block-on-roller type multi-tribotester machine. The mechanical properties and wear behavior of the AGI samples are also determined and discussed systematically. Results showed that the mechanical and wear properties of AGI are significantly enhanced in comparison with as-cast gray iron. The wear behavior of AGI samples may be correlated with microstructure and mechanical properties. The hardness, tensile strength, elongation and volume fraction of austenite act as independently in influencing the wear behavior.
10.1007-s12046-023-02248-3	1	shape; memory; shape memory; damping; martensite; martensitic; damping capacity; transformation; capacity; strain; superelasticity; temperature; cu-al-mn; shape memory effect; effect	This paper presents the empirical correlations to predict the phase transition temperatures of CuAlMn based shape memory alloy thermal/heat switches. The correlations can precisely predict the start and finish phase transition temperatures of austenite and martensite lattice structures within the error range of +/- 18% at different Cu/Al and Cu/Mn compositions in CuAlMn shape memory alloy. Moreover, for the first time, contours on the effect of Cu/Al ratio on phase transition temperatures are analyzed in detail. It has been found that 'Mn' compassions in CuAlMn alloy play a critical role, and should be at the higher end of composition to achieve low-temperature actuation (<123 K), enhanced switching ratio, and overall performance improvement in shape memory alloy-based heat switches. The precise performance prediction of CuAlMn based shape memory alloy will be helpful in the design of effective mechanical heat switches for low-temperature space applications.
10.1007-s12206-025-0721-4	14	strength; properties; conductivity; electrical; mechanical; cu-; grain; mpa; electrical conductivity; aging; precipitation; phase; mechanical properties; tensile; phases	This study investigates the tensile behavior of Cu-Zr-based bulk metallic glasses (BMGs) with varying concentrations of Al, Ti, and Ni through molecular dynamics simulations. The effects of alloying composition and temperature on mechanical properties are examined. Results show that Al addition enhances Young's modulus and structural rigidity, while Ti exhibits a non-monotonic effect-initially improving mechanical properties but diminishing them at higher concentrations. In contrast, Ni consistently strengthens the alloy by enhancing atomic packing efficiency. Elevated temperatures reduce both yield strength and peak stress, with the Cu-Zr-Ti alloy showing the highest susceptibility to thermal softening. These findings offer valuable insights for the design and optimization of high-performance BMGs for structural applications.
10.1007-s12289-009-0661-z	5	materials; thermal; heat; properties; material; welding; sintering; fusion; strength; laser; heat sink; thermal conductivity; mechanical; sink; manufacturing	Copper (Cu) has some properties, similar to aluminium (Al), like high thermal conductivity, high thermal expansion coefficient, relatively low melting point, brittleness at elevated temperatures and less viscosity of molten metal. These properties make the welding of Cu and Cu alloys difficult as compared to welding of carbon steels. The present study investigates the feasibility of electromagnetic impact welding of Cu-to-Cu sheets by using Al as the driver sheet. A study has been carried out to characterize the electromagnetic impact welding of 0.5 mm thick Cu sheets. The results of the microstructure and tensile shear strength tests are reported.
10.1007-s12289-017-1373-4	-1		Incremental Sheet Forming (ISF) and particularly its Single Point (SPIF) variant has been studied intensively over the last years given the potential for low-cost prototyping and small batches production. Numerical and experimental works have been covering a widespan of materials and geometries. This paper fills an important gap regarding studies of the SPIF process applied to brass alloys, and particularly the commonly used Cu-35Zn brass alloy. Despite being a material widely used in industry for centuries, with excellent cold formability and innumerous applications, there is still no relevant information on the mechanical response and properties of this material under SPIF. This research is based in SPIF experiments with brass alloy sheets with different thicknesses (0.50, 0.70 and 1.00 mm), to obtain data such as forming forces or forming fracture lines to be compared against standard forming limit diagrams or against other materials under ISF. Other data like friction during the process was evaluated as well. Fifteen sets of experiments were conducted, using different values of step down (0.10, 0.50 and 1.00 mm) and two forming tools with diameters 10 and 15 mm.
10.1007-s12520-010-0027-y	2	corrosion; surface; film; electrochemical; films; spectroscopy; layer; current; solution; potential; resistance; composition; x-ray; ions; showed	Copper isotopes can be successfully used to determine the origin of copper or bronze artefacts from either primary or supergene sulphide or hydrocarbonate ores. In conjunction with lead isotopes, they provide information on the origin and type of the metal ore. We demonstrate this in this paper from the combination of literature and own data on metal ores and artefacts (coins and ingots). Low-temperature hydrocarbonates (esp. malachite and azurite) do not fractionate the copper isotopes amongst each other and have identical lead isotopes. Substantial fractionation of copper isotopes, however, occurs between copper sulphides and hydrocarbonates (malachite, azurite) such that the Cu-65 isotope is always enriched in the oxidised relative to the sulphide phase with a clear distinction between the two ore types. Expressed in the delta Cu-65 notation, we assigned supergene sulphides to values less than -0.4 parts per thousand down to negative values of -2 parts per thousand and more, primary sulphides to a range between -0.4 and +0.3 parts per thousand and hydrocarbonates to positive values higher than +0.3 parts per thousand. We have applied these boundaries to copper coins and ingots from the time of the Roman emperors with known ages from Augustus up to 250 AD. The deposit fields of the metal used for the production of the coins were previously identified from the lead isotope ratios to lie in the Southwest and the Central South of Spain. From the combination of the lead and copper isotopes and the exact time constrains, we could develop a picture of the change in mining activities in Spain involving continued mining sulphide ore deposits and, indicated by positive delta Cu-65 values as proxies for malachite and azurite, the opening of new mines in various time slots. This first application shows that copper isotopes will become the most important tool in archaeometallurgy to distinguish between the exploitation of deeper-seated primary and supergene sulphide ores and shallower, secondary hydrocarbonate ores. This will become especially relevant for archaeometric questions regarding the distinction between occasional and intentionally produced alloys.
10.1007-s12520-017-0534-1	2	corrosion; surface; film; electrochemical; films; spectroscopy; layer; current; solution; potential; resistance; composition; x-ray; ions; showed	The chemical composition of ancient copper-based metal changes over time due to repetitive recycling and mixing of old metal. Prehistoric copper usually contains impurities from the copper ores themselves, and some have been used as evidence of anthropomorphically induced chemical change. Research into these changes has historically relied upon the assumption of element loss linearity, which is highly misleading and in fact varies with a multitude of factors. To illustrate the complexity of such losses for prehistoric alloys, we have selected arsenical bronze (Cu-As alloys) for study. The mass loss of several Cu-As-alloys under reducing atmosphere was measured by DTA/TGA. From our comparison of the experimental results to thermodynamic calculations and literature data, it was unclear whether weight losses were solely caused by the elemental loss of arsenic. However, a prolonged time temperature-cycling run demonstrated that mainly arsenic volatilizes; hence, the non-linear mass loss from the alloy can be directly attributed to arsenic.
10.1007-s12520-022-01633-z	2	corrosion; surface; film; electrochemical; films; spectroscopy; layer; current; solution; potential; resistance; composition; x-ray; ions; showed	Archaeological works at Cabeco Redondo (southern Portugal), located in the Guadiana River basin, identified the remains of a monumental building with an architecture, ceramics and metal artefacts in line with post-Orientalizing contexts of the sixth-fifth century BC in southwestern Iberian Peninsula. Metal debris connected to the copper-based metallurgy include a significant collection of ingots, lumps and small prills, with emphasis to a massive plano-convex ingot, while artefacts comprise tools, small implements, ornaments and rods. A chemical and microstructural study involving micro-EDXRF, optical microscopy and SEM-EDS provided some answers about foundry activities and identified the composition and post-casting manufacture of artefacts. Most metal debris were composed of pure copper (>99 wt% Cu), although some examples attest the use of bronze and leaded bronze at Cabeco Redondo metallurgical workshop. Apart from a few copper items, the artefact collection mainly shows low-tin bronze alloys (7.6 +/- 3.9 wt% Sn) and leaded bronze alloys (7.7 +/- 4.4 wt% Sn and 6.0 +/- 3.4 wt% Pb). The manufacture of copper and binary bronze artefacts included hammering and annealing, while leaded bronzes were usually not subjected to post-casting work, implying a well-defined relation among function, composition and manufacture. The features of metal debris and artefacts were then compared with the ones of coeval sites of this region to integrate the metallurgical evidence of Cabeco Redondo into the technological pattern of southwestern Iberian Peninsula during the middle of the first millennium BC.
10.1007-s12520-023-01853-x	2	corrosion; surface; film; electrochemical; films; spectroscopy; layer; current; solution; potential; resistance; composition; x-ray; ions; showed	We present a detailed analysis of the chemical alloying data (Cu, Sn, Pb) on the bronzes recovered from the Late Shang capital at Yinxu, revealing a complex pattern which varies by social status and object typology, and which also changes over time. The preference for higher tin in the bronze vessels and weapons for the elites during Yinxu Phase II gives way to a more binary pattern (with weapons being preferentially alloyed with lead) for the lower elites of phase II, which becomes prevalent in subsequent phases. These changes are interpreted in terms of different 'alloying practices', which attempts to reconstruct the way in which the alloys are created at the point of casting. The alloy type described here as A1/A2 (11-24% tin, 0 to 3-5% lead) seems most likely to have been created by mixing together three components, corresponding to mixing relatively pure copper, tin and lead. This contrasts with the suggestion in the Kaogong Ji, several hundred years later, that binary pre-prepared alloys were used. It is now important to determine when such a change might have occurred. The suggestion that alloy type B (low tin, variably high lead) could have been made by combining pure copper with a slightly impure lead (95%Pb/5%Sn) hints that such practices might have started during the Shang, but requires more work, especially on the intervening Western and Eastern Zhou periods.
10.1007-s12520-024-02123-0	2	corrosion; surface; film; electrochemical; films; spectroscopy; layer; current; solution; potential; resistance; composition; x-ray; ions; showed	A group of metal objects excavated at Qasr-e Abu Nasr in south-central Iran in the 1930s, now in the collection of the Metropolitan Museum of Art, has been analyzed to examine metalworking techniques and metallurgical processes. Thirty-three objects were studied and analyzed by micro-X-ray fluorescence, scanning electron microscopy-energy dispersive X-ray spectroscopy, and metallography techniques. The results of these analyses show a wide range of copper alloy compositions including impure copper, tin bronze, brass, leaded tin bronze, leaded brass and leaded ternary Cu-Sn-Zn (gunmetal) alloys. Also, two silver-copper and one pewter object were identified among the analyzed objects. The results of this interdisciplinary study provide new insights onto the archaeology of Qasr-e Abu Nasr, as well as present new information about the history and evolution of copper-base metallurgy on the Iranian Plateau during the Sasanian and early Islamic periods.
10.1007-s12540-009-0555-0	15	aging; strength; conductivity; electrical conductivity; electrical; mpa; treatment; strengthening; degrees; cu-; cold; precipitation; tensile strength; tensile; iacs	Cu-Ag-Zr alloy is a newly developed copper alloy material which has an excellent combination of high mechanical strength and high electrical conductivity. By means of vacuum induction melting, Cu-Ag-Zr alloy was produced. The effects of aging processes on the microhardness and electrical conductivity characteristics of Cu-Ag-Zr alloy were studied. After aging at 450 A degrees C for 4h, the alloy showed an excellent combination of microhardness and electrical conductivity: the microhardness and electrical conductivity reach 126 HV and 84%IACS, respectively. The precipitates responsible for the age-hardening effect are the fine and dispersed Cu5Zr, which has a face center cubic structure. Cu5Zr precipitates are fully coherent with the Cu matrix and give the Cu-Ag-Zr alloy higher microhardness and higher electrical conductivity.
10.1007-s12540-011-0622-1	-1		Supersaturated Cu-Sn alloy sheets were successfully fabricated by hot-rolling mechanically alloyed (MAed) nanocrystalline powders within a range of up to 22 wt% of Sn, and their antibacterial and ionization properties were investigated. While the pure Cu and hot-rolled Cu-Sn sheets using MAed powders show excellent antibacterial properties, the corrosion potential of the hot-rolled Cu-Sn using MAed powders is much less than that of the as-cast Cu-Sn and decreases as the Sn content increases, implying that the hot-rolled Cu-Sn alloy sheets using MAed powders have a more effective antibacterial property, mainly due to supersaturation.
10.1007-s12540-012-0014-1	-1		Copper powder was cryomilled for 12 hours to achieve particle size in the range of 2 mu m to 25 mu m, which powder was subsequently used as feedstock for the deposition of nanocrystalline (nc) Cu coating via cold spraying. The as-milled copper powder was characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM) and high resolution transmission electron microscopy (HRTEM). The particle size of the cryomilled Cu powder was detected by laser scattering. The microstructure of the coating was analyzed using SEM and scanning transmission electron microscopy (STEM). The XRD and HRTEM analysis showed that the grain size of the cryomilled Cu powder was about 5 to 40 nm. This nanoscale structure was retained after the cold spraying. The nanoindentation analysis showed that the nc Cu coating hardness value reached 3.3 GPa, which was higher than that of its coarse grained counterpart.
10.1007-s12540-014-4012-3	11	glass; bulk; metallic; bulk metallic; gfa; bmg; glassy; metallic glass; ability; bulk metallic glass; amorphous; addition; crystallization; mm; glass-forming	The thermal stability and crystallization kinetics of the Cu (x) Zr84-x Al8Ag8 (x = 42, 40, 38, and 36) bulk metallic glasses (BMGs) were studied by measurement of isothermal electrical-resistance. As the composition becomes richer in Zr, the longer incubation time at the same relative annealing temperature, and the larger local activation energy needed to achieve the same crystallized volume-fraction, indicate improved thermal stability, which resists crystallization. The improved thermal stability is attributed to a denser atomic random-stacking structure and larger negative heat-of-mixing. During isothermal annealing processes, the four BMGs exhibited the same nucleation mechanism, which is a decreasing rate of nucleation over time. However, the crystal growth mechanisms of the four BMGs are different. The crystallization of the Cu36Zr48Al8Ag8 and Cu38Zr46Al8Ag8 BMGs is interface-controlled growth, contrasting with diffusion-controlled growth for the Cu40Zr44Al8Ag8 and Cu42Zr42Al8Ag8 alloys. The different growth modes may be caused by fluctuations in composition due to changes in the quantity and distribution of Cu-rich and Ag-rich regions.
10.1007-s12540-015-3469-z	-1		-situ synthesis casting process, which is a new method of the spray casting that can produce ODS preform in a single process. Its microstructure and mechanical properties of sintered compact was investigated. Cu/Al2O3 ODS alloys were produced by spraying with the mixed gas containing various oxygen volume fraction between 0-8 vol%. Al2O3 at deposited alloy was observed from the oxygen content of 3 vol%, and the area fraction of Al2O3 increased with increasing oxygen contents. Al2O3 was observed at the interface between droplets, and its morphology was irregular such as linear or circular shape. It seemed that oxide layer was broken and deposited on the substrate owing to the selective oxidation at the atomization zone. In sintered compacts, Al2O3 was found at grain boundary. Mechanical properties improved with the increase of oxygen volume fraction owing to the dispersion strengthening of Al2O3.
10.1007-s12540-016-5459-1	-1		Mossbauer spectroscopy and X-ray diffraction have been used to study the kinetics of structural and phase transformations in Cu + 2 at% Fe-57 during mechanical activation in liquid media (heptane, distilled water) and subsequent heat treatment (600 and 700 degrees C). The initial stages of mechanical alloying are associated with the transition of components to the nanostructural state. Iron atom groups form near the grain boundaries, and isolated iron atoms penetrate from the boundaries into the grains. Oxidation of groups of iron atoms that form highly dispersed phases of ternary oxide and magnetite occur in the initial stages of mechanical alloying of Cu + 2 at% Fe-57 in water. The formation of the solid solution in the form of isolated iron atoms in the lattice of copper proceeds, regardless of the milling media used. Samples prepared in heptane contain carbon and oxygen, and upon heat treatment, carbide and oxide phases are formed.
10.1007-s12540-016-5569-9	-1		Nanoporous microtubes of a nickel-copper alloy were obtained from a Cu-44Ni-lMn (wt%) commercial wire (200 mu m diameter). A new synthesis method was established through three steps: 1) partial oxidation of the wire at 1173 K in air, 2) removal of the inner unoxidized core by chemical etching, 3) reduction in 10 bar hydrogen atmosphere. During oxidation, the segregation of Cu and Ni occurred because of their different diffusion coefficients in the corresponding oxides. As a consequence, pores were formed by Kirkendall effect and due to selective chemical etching of the different oxides. Additional porosity formed because of volume contraction during reduction with hydrogen. After reduction, the microtube shows a composition gradient from the inner wall (almost pure nickel) to the outer wall (almost pure copper). The process allowed to obtain microtubes with tuneable wall thickness and inner pores around 180 +/- 80 nm. The morphological features developed suggest improved capillarity properties for applications in MEMS.
10.1007-s12540-016-6083-9	-1		An in situ porous TiO/Cu composite is successfully prepared using powder metallurgy by the reaction of Ti2CO and Cu powder. Morphological examination of the composite shows that the porosity of composites lies in the range between 10.2% and 35.2%. Dry sliding un-lubricated wear tests show that the wear resistance of the composite is higher than that of the Cu-Al alloy ingot. The coefficient of friction test shows that, as the volume fraction of the reinforced phase increases, the coefficient of friction decreases. The wear rate variation trend of the oil-lubricated wear test results is similar to that of the un-lubricated wear test results. The coefficient of friction for oil lubrication is similar for different volume fractions of the reinforced phase. The wear resistance of the composite at a sliding velocity of 200 rpm is slightly larger than that at 50 rpm. The porosity of the composites enhances the high-velocity oil-lubricated sliding wear resistance.
10.1007-s12540-016-6156-9	-1		Cu-Ni-Si alloys with and without Ti were solution treated at 980 A degrees C for 1 h and cooled by air cooling and water quenching, after which the specimens were aged at 500 A degrees C. The two alloys showed different aging characteristics with different cooling rates during the aging process. The conductivity of all alloys increased during aging; for alloys that were water quenched, hardness increased at the early stage of aging and then drastically decreased. The air-cooled Cu-Ni-Si alloy without Ti also experienced an increase in hardness, which then decreased during aging, but the air-cooled Cu-Ni-Si alloy with Ti did not show a drastic decrease in hardness during prolonged aging. A combination of yield strength and conductivity of 820 MPa and 42% IACS, respectively, was achieved in the air-cooled Cu-Ni-Si-Ti alloy after solution treatment.
10.1007-s12540-016-6386-x	-1		The effect of the type of the crystalline phase and its volume fraction on the mechanical property of Cu50Zr50-xTix alloys (x = 0-10) bulk metallic glass composites has been investigated in this study. Up to 6 at% of Ti, B19' phase particles distributed in the glassy matrix, while at 8 and 10% of Ti, B2 phase particles are retained in the glass matrix due to suppression of the eutectoid transformation of B2 phase and by avoidance of martensitic transformation of B2 into B19'. The volume fraction of crystalline phase is strongly dependent on the cooling rate. The larger volume fraction of the crystalline phases results in the lower yield stress, the higher plastic strain, and the more pronounced work hardening behavior. At the crystalline volume fraction below similar to 30%, the variation of the yield strength can be described by the rule of mixture model (ROM), while at the crystalline volume fraction higher than similar to 50% by the load-bearing model (LBM). At the crystal fractions between 30 and 50%, there is a yield strength drop and a transition from the ROM to the LBM. This transition is due to the formation of the crystalline structural framework at higher crystal fraction.
10.1007-s12540-017-6417-2	-1		Cu-Ag composite is one of the best conductors for high-field magnets. Increasing its strength is crucial for designing newer high-field magnets. Cu-28 wt%Ag samples were solidified with and without a 12-T high magnetic field (HMF), and then cold-drawn. We investigated the influence of HMF on microstructure, hardness and strength of Cu-Ag samples both before and after cold-drawing. The introduction of external HMF during solidification increased both the dendrite arm spacing and the dissolved Ag in Cu, and it reduced the spacing between both the Ag precipitates in proeutectic Cu and the eutectic lamellae. The transversal microstructure after cold-drawing inherited the network solidification structure, but at a refined scale. The Cu dendrite spacing in the 12-T HMF samples at all deformation strain was larger than that without HMF. HMF slightly increased the intensity of <111> fiber texture of Cu, which strengthened proeutectic Cu at the level of 3.5 deformation strain. In samples deformed to strain of 3.5, refined Ag precipitation spacing, increased Ag solubility in Cu matrix, and refined eutectic lamellar spacing by 12-T HMF increased the strength by 5% in the sample compared with that without HMF.
10.1007-s12540-018-0025-7	-1		The microstructures and tensile properties of Cu-3 wt%Ag-0.5 wt%Zr alloy sheets under different aging treatments are investigated in this research . As one kind of precipitate, Ag nanoparticles with coherent orientation relationship with matrix precipitate. However, after the peak-age point, most of Ag nanoparticles grow into short rod shape with the interface translating to semi-coherent, which leads to the lower strength of over-aging sample. The yield strength is estimated by considering solid solute, grain boundary and precipitation strengthening mechanisms. The result shows that the Ag precipitates provide the main strengthening role. Then a constitutive equation representing the evolution of dislocation density with plastic strain is built by considering work-hardening behavior coming from shearable and non-shearable precipitates which is mainly the particles containing Zr. The flow stress contributed by shearable particle hardening is higher than that of non-shearable one. Due to the coarsening of grain boundary precipitates and low rate of damage accumulation of these non-shearable particles, the micro-cracks nucleate easily at grain boundary which leads to intergranular fracture.
10.1007-s12540-018-0114-7	11	glass; bulk; metallic; bulk metallic; gfa; bmg; glassy; metallic glass; ability; bulk metallic glass; amorphous; addition; crystallization; mm; glass-forming	Microstructural evolution during injection casting Cu50Zr50-xTix (x = 0-8) alloys has been investigated using X-ray diffractometry, differential scanning calorimetry, scanning electron microscopy and transmission electron microscopy. Cubic CuZr(Ti) B2 phase is competing against the glass transition during solidification for all the alloys and the primary B2 phase has transformed into the martensitic phase for x < 6 alloys during cooling after solidification. The formation of spherical morphology and spatially inhomogeneous distribution of B2 phase in a glassy matrix can be rationalized in terms of reduced interface kinetics of solid/liquid interface and polymorphic nature of the primary solidification taking place without solute partition. The partial replacement of Zr with Ti improves not only glass forming ability but also suppresses the martensitic transformation of B2 phase, enabling the fabrication of BMG composites consisted of the B2 phase embedded in a CuZr(Ti) glass matrix. However, due to local cooling rate change during solidification, development of non-uniform microstructure in the BMG composites seems to be inevitable, which may be an obstacle in future application of the BMG composites.
10.1007-s12540-018-0133-4	0	solidification; phase; magnetic; magnetic field; undercooling; field; liquid; separation; peritectic; immiscible; cu-; dendrite; phase separation; microstructure; primary	A rotating magnetic field (RMF) was applied in the solidification process of Cu-8Fe alloy. Focus on the mechanism of RMF on the solid solution Fe(Cu) atoms in Cu-8Fe alloy, the influences of RMF on solidification structure, solute distribution, and material properties were discussed. Results show that the solidification behavior of Cu-Fe alloy have influenced through the change of temperature and solute fields in the presence of an applied RMF. The Fe dendrites were refined and transformed to rosettes or spherical grains under forced convection. The solute distribution in Cu-rich phase and Fe-rich phase were changed because of the variation of the supercooling degree and the solidification rate. Further, the variation in solute distribution was impacted the strengthening mechanism and conductive mechanism of the material.
10.1007-s12540-019-00405-0	-1		This paper is to disclose the plastic deformation mechanism of 3 Nb-alloyed bulk metallic glasses and composites via the analysis of serration dynamics. The as-cast alloys with 1.0 at% and 2.0 at% of Nb element display the large time window of serrated events, implying that the serrated behavior can dynamically retain in a long-time scale and thus the alloys are endowed the largest compressive plasticity. The statistic results suggest that the serrated flow of both alloys with 1.0 at% and 2.0 at% Nb element achieves the self-organized critical state. The normal probability plots were utilized to further evaluate serrated dynamics and demonstrate that large deviations from the mean value of stress drops facilitate the self-organized critical state of serrations. This work suggests that large plastic bulk metallic glasses and composites are characterized by non-normal probability of serration statistics during plastic deformation.
10.1007-s12540-019-00422-z	2	corrosion; surface; film; electrochemical; films; spectroscopy; layer; current; solution; potential; resistance; composition; x-ray; ions; showed	In this work we report attempts to inhibit corrosion of Cu substrates in 0.6 M NaCl solution by coating with 100 nm Ni film and post-annealing with oxygen at different temperatures, in order to convert the nickel to nickel oxide. Electrochemical impedance spectroscopy (EIS) and polarization measurement analyses were used to obtain electrochemical data. The correctness of the EIS results was confirmed by Kramers-Kronig transformation, while fitting of the data (Nyquist and Bode diagrams) to suitable equivalent electrical circuits showed that the highest corrosion enhancement is achieved for the Ni/Cu sample annealed at 473 K, resulting in a 98% corrosion inhibition enhancement factor (eta%). Polarization measurements also showed that this sample has the lowest corrosion current density, lowest corrosion rate and highest corrosion potential with a 97% corrosion inhibition efficiency factor (PE%). Consistent results are achieved for EIS and polarization measurements which are then correlated with the nanostructure of the films using X-ray diffraction and atomic force microscope analyses. Graphic
10.1007-s12540-019-00570-2	4	transformation; martensite; martensitic; phase; shape; beta; memory; shape memory; temperature; temperatures; martensitic transformation; gamma; transformation temperatures; effect; thermal	Effect of nano-CeO(2)doping was studied on self-accommodating Cu-12Al-4Ni based shape memory alloys. Cu-Al-Ni based alloys are known for their high thermal stability and good shape memory properties but mechanical processing of these alloys is very difficult due to their high brittle nature and susceptibility to inter-granular failure. The present work deals with the enhancement of mechanical as well as shape recovery characteristics of these alloys with the addition of nano-CeO2. Significant improvements in ductility (1.8 times), strength and shape recovery were observed with the addition of nano-CeO(2)with respect to the base alloy. Graphic
10.1007-s12540-020-00801-x	-1		Due to its corrosion resistance, modifiable mechanical properties, and electrical conductivity, etc., CuNi alloy has found a wide variety of industrial applications, especially in the marine environment. It is highly desired if the mechanical strength and wear resistance of CuNi alloy can reach a level comparable to that of steel while keeps its corrosion resistance. In this study, effects of Mo, B, and their combinations on microstructure and performance of CuNi alloy were investigated, including formation of second phases, hardness, and resistances to wear, corrosion and corrosive wear. It was demonstrated that the Mo and B additives were effective in strengthening the CuNi alloy while maintaining reasonable corrosion resistance. In particular, the combination of Mo and B additives was more effective than a single additive to strengthen the alloy. Mo and B additives have demonstrated their great promise as new alloying elements to modify CuNi alloys.
10.1007-s12540-021-01052-0	-1		The effect of aging processes on the tensile properties of C-18150 copper alloy samples, made by laser powder-bed-fusion additive manufacturing (AM) process with three different fabrication orientations (horizontal, angled, and vertical to the build direction), are investigated. For the as-fabricated C-18150 AM parts, horizontal and angled fabrication directions result in marginally better tensile strengths and much improved strain-to-failure values than those of vertically built AM parts. After the aging treatment, tensile strength can be significantly enhanced with a sacrifice of the strain-to-failure value. Moreover, the highest tensile strength is achieved by treating the as-fabricated samples at an aging temperature of 500 degrees C for 2 h . At 800 degrees F (427 degrees C), both tensile strength and ductility are smaller than low temperature values (room temperature and 400 degrees F/204 degrees C). Phase constituents, microstructure, and composition distribution of the AM parts are characterized to gain insight into the measured tensile properties. [GRAPHICS] .
10.1007-s12540-021-01153-w	15	aging; strength; conductivity; electrical conductivity; electrical; mpa; treatment; strengthening; degrees; cu-; cold; precipitation; tensile strength; tensile; iacs	Novel ultrahigh strength Ni2Si strengthened brasses were fabricated, and microstructure and properties were investigated using scanning electron microscopy, optical microscopy, transmission electron microscopy, X-ray diffraction analysis, hardness measurement, and electrical conductivity test. After optimal treatments (solid solution treated at 900 degrees C for 2 h, hot-rolled by 80%, cold-rolled by 80%, and ageing treated at 300 degrees C for 8 h), the Cu-20Zn-3Ni-0.68Si alloy's hardness, tensile strength, yield strength, and electrical conductivity is 270.6 HV, 964 MPa, 933 MPa, 21.6%IACS, and 3.4%, respectively. delta-Ni2Si precipitates formed during the annealing process, which had a crystal orientation relationship with the matrix: (001)(m)// (001) (delta), and [110](m)// [100](delta). Quasi-cleavage fracture surfaces with shallow dimples were presented in both the Cu-20Zn-1.5Ni-0.34Si and the Cu-20Zn-3Ni-0.68Si alloy. These findings give a new method to develop new high strength low-cost brass copper materials.
10.1007-s12540-021-01164-7	-1		This paper aims to indicate the role of alloying composition on the nanomechanical properties of metallic glasses (MGs). For this purpose, the molecular dynamics simulation of nanoindentation process was performed for a wide range of Cu-Zr glassy compositions. The results indicated that the yielding event enhanced with the rise of Cu content; however, there existed an optimized composition for the maximum hardening effect in the system. The investigation on the evolution of shear bands also showed that the formation of pile-ups around the indentation site and the propagation of dominant shear bands into the glassy structure occurred in the Cu-rich MGs. On the other side, the increase in Zr content led to the creation of a net-like shear arrangement under the indented site. Moreover, the Voronoi tessellation analysis indicated that the decreasing/increasing rate of polyhedron types during the indenting process strongly relied on the alloying compositions.
10.1007-s12540-022-01324-3	-1		Cu-Fe alloys have drawn extensive attraction due to excellent multi-functional properties, including electrical, magnetic, and mechanical properties. However, the immiscible nature of Cu-Fe alloys results in heterogeneous microstructure and unexpected mechanical properties. In this study, a small amount of Zr was added to the cast Cu60Fe40 (wt%) alloy to suppress the liquid-liquid phase separation during solidification of the alloy. The microstructure and mechanical properties of the Zr-free and Zr-containing Cu-Fe alloy were investigated. It is found that the addition of Zr successfully inhibits the heterogeneous microstructural evolution caused by liquid-liquid phase separation, while the FeZr-rich precipitates form in the dual-phase microstructure. The FeZr-rich precipitates affect grain growth of the Zr-containing alloy through the Zener pinning effect, leading to extra grain boundary strengthening and precipitation hardening. The resulting microstructure of the Zr-containing alloy substantially enhances the strength of the alloy with a loss of ductility. The fractured surface reveals that microcracks are formed near the precipitates, which is associated with the reduced elongation of the Zr-containing alloy.
10.1007-s12540-023-01448-0	-1		Double-pass friction-stir processing (FSP) with different probe lengths and coolants was conducted on a 3 mm thick Cu30%Zn alloy plate, and a heterogeneous lamella structure (HLS) was produced along the plate thickness direction. The HLS can be divided into three layers with their volume ratio was approximately 1:1:1, i.e., ultra-fine grain layer, fine grain layer, and coarsened grain layer which produced by cold source assisted FSP, conventional FSP, and annealing treatment, respectively. The average hardness in ultra-fine grain layer was about 123 HV, which was significantly higher than those of coarsened grain layer (94 HV) and fine grain layer (105 HV). In each layer, the hardness slightly decreased with distance increased from the surface, but the hardness value decreased sharply in the transition zones of different layers. The HLS Cu-30%Zn alloy showed yield strength of 220 MPa, ultimate tensile strength of 462 MPa, and fracture elongation of 30%. The strength- ductility synergy was attributed to the back-stress strengthening between the different layers, which induced a remarkable strain hardening at the initial stage of plastic deformation. This study provided a possible way for preparing HLS copper alloys with relatively good mechanical properties, and the HLS copper alloys have an application potential in the manufacture of bearing, propeller, and condenser.
10.1007-s12540-023-01489-5	-1		Electroplated copper is a key electronic interconnect material in integrated circuits and printed circuits and inevitably exposed to corrosive media in manufacturing processes. The present work reports, for the first time, that corrosion resistance of electroplated copper in 4 wt% NaOH is enhanced via nanotwinned microstructure engineering. Nucleation and growth of oxide/hydroxide on nanotwinned copper are inhibited, attributed to existence of highly (111)-preferred grain orientation and high-density parallelly-aligned coherent twin boundaries at surface. This study unveils a novel anti-corrosion strategy of nantowinned microstructure engineering against alkaline etchant, and exhibits great application values in industrial electroplating of copper, silver, or their alloys.
10.1007-s12540-024-01626-8	-1		In order to obtain homogeneity and fine-scale microstructure of Cu-Fe alloy, a Cu-10 wt% Fe alloy slab was prepared by spray forming. The effects of cold rolling reduction on the alloy microstructure, mechanical properties, and electrical conductivity were studied. The results indicate that the Fe phase was fine and uniform with an average particle size of 4.16 mu m, and the morphology of the particles was short rod or nearly spherical. The Cu matrix and Fe particles were gradually elongated, refined and finally formed into a distinct fiber structure along the rolling direction as the cold rolling reduction increased from 35 to 95%. The degree of deformation of the Cu matrix was more significant than that of the Fe phases at the same reduction, and more refined grains of the Cu matrix around the Fe phases. After cold rolling at 95% reduction, the Cu-10 wt% Fe exhibited an increase in tensile strength from 337 MPa in the initial state to 595 MPa, while the electrical conductivity decreased from 42.3% IACS to 20.2% IACS. The alloy deformation behavior and the strengthening mechanisms were illustrated. The combination of spray forming and cold rolling provides a novel approach to producing efficient, shortened process, environmentally friendly Cu-Fe alloy thin strips.Graphical AbstractA new process of preparing homogeneity and fine-scale microstructure Cu-10 wt% Fe alloy thin strip by spray forming and clod rolling is proposed. Fine and uniform Fe particles were obtained with an average size of 4.16 mu m. Combined with the subsequent cold rolling, the effects of different reductions on the microstructure and mechanical properties after cold rolling were systematically studied. The specific abstract summary is as follows:
10.1007-s12540-024-01651-7	-1		Continuous extrusion is a very promising technique for forming Cu-Cr-Zr alloys which takes the upward continuous casted rods as raw materials. While the hot deformation behavior and constitutive equation of as-cast rods have never been reported. In the present study, the hot deformation behavior of as-cast Cu-Cr-Zr rods with columnar grains was investigated. The results showed that the flow stress at 500 degrees C is higher than that at 400 degrees C. The reason for that can be attributed to the dynamic precipitation process, which was confirmed by TEM observations. At this temperature, partial CDRX dominates the softening mechanism while at high temperatures DRV and DDRX play a critical role. The constitutive equation was then established and the deformation activation energy was determined to be 541.93 kJ/mol. The high activation energy was attributed to the large solidified columnar grains. At high strains, stable metal flows can be obtained at high strain rates and high temperatures according to the processing maps, which indicates that a high-speed deformation at a high temperature is favorable to the plastic forming of this material. This investigation thus provides valuable information on how to process the Cu-Cr-Zr rods by plastic deformation methods, for example, continuous extrusion.
10.1007-s12540-025-01928-5	14	strength; properties; conductivity; electrical; mechanical; cu-; grain; mpa; electrical conductivity; aging; precipitation; phase; mechanical properties; tensile; phases	This study examines the influence of Multi-Axial Compression (MAC) and annealing on texture evolution, grain boundary behavior, and plastic anisotropy in Cu-Zn alloys. The MAC process effectively reduces the formation of dominant copper- and brass-type textures by altering the strain path, promoting a more random texture distribution and reducing anisotropy. Texture Index (TI) values show that MAC significantly brings the alloy's texture closer to ideal isotropy. During annealing, continuous recrystallization (RX) occurs, driven by organized dislocation structures with low dislocation arrangement indication M* values, which means disorderly arranged dislocations are first annihilated. Additionally, the formation of Sigma 3 coincident site lattice (CSL) boundaries plays a crucial role in suppressing grain growth, leading to a stable microstructure. The reduction in plastic anisotropy is confirmed by tensile test results, while conventional high electrical conductivity is maintained. The combined MAC and annealing processes demonstrate a promising method for improving the formability and retaining electrical performance of Cu-Zn alloys by controlling texture evolution and plastic anisotropy.
10.1007-s12541-014-0473-z	-1		Contact wire is one of the most important components used to supply electricity to railway vehicles which equipped with a pantograph . When the speed of electric vehicle is not as high as now, the failure of contact wire caused by friction and wear behaviors of carbon strip/contact wire were considered more important. But the fatigue fracture become more and more important for the failure of contact wires on account of several fatigue fractures happened while the speed of electric vehicle increase continuously A bending fatigue tester simulating the working conditions of contact wires developed by Kang and etc has been used to evaluate the fatigue characteristic of pure copper and Cu-Sn alloy contact wires. In this study, this bending fatigue tester also is used to evaluate the fatigue characteristics of Cu-Mg alloy contact wire which developed for 400Km/h high speed rail in Korea. Test result is also compared with the result of Kang's research on pure copper contact wire. Finally, in order to evaluate the fatigue life of contact wires for any mean stress, the relationships between plastic strain and fatigue life were abstained for two kinds of contact wires combined the FE analysis.
10.1007-s12541-017-0103-7	2	corrosion; surface; film; electrochemical; films; spectroscopy; layer; current; solution; potential; resistance; composition; x-ray; ions; showed	This paper reports the effects of the stirring rate of the solution, boric acid concentration, and applied current density on the formation of the copper-cuprous co-electrodeposited structure. For copper-cuprous co-electrodeposition, 0.5 M CuSO4 center dot 5H(2)O solution was used. When electrodeposition was performed via stirring and the addition of boric acid, pillar-type electrodeposited structures were formed. On the other hand, when electrodeposition was carried out without stirring or the addition of boric acid, hill-type electrodeposited structures were formed. Development of the pillar structure was promoted by increasing the boric acid concentration and the stirring rate. The electrodeposited structure was applied to surface modification in order to verify its industrial effectiveness. When the concentration of the added boric acid was higher than 0.5 M and the stirring rate of the solution was 200 rpm, the fabricated specimens showed superhydrophobic properties after hydrophobic layer coating.
10.1007-s12598-010-0147-7	11	glass; bulk; metallic; bulk metallic; gfa; bmg; glassy; metallic glass; ability; bulk metallic glass; amorphous; addition; crystallization; mm; glass-forming	Cu46Zr47-xAl7Mx (M = Ce, Pr, Tb, and Gd) bulk metallic glassy (BMG) alloys were prepared by copper-mold vacuum suction casting. The effects of rare-earth elements on the glass-forming ability (GFA), thermal stability, and mechanical properties of Cu46Zn47-xAl7Mx were investigated. The GFA of Cu46Zr47-xAl7Mx(M = Ce, Pr) alloys is dependent on the content of Ce and Pr, and the optimal content is 4 at%. Cu46Zr47-xAl7Tbx (x = 2, 4, and 5) amorphous alloys with a diameter of 5 mm can be prepared. The GFA of Cu46Zn47-xAl7Gdx(x = 2, 4, and 5) increases with increasing Gd. T-x and T-p of all decrease. T-g is dependent on the rare-earth element and its content. Delta T-x for most of these alloys decreases except the Cu46Zr42Al7Gd5 alloy. The activation energies Delta E-g, Delta E-x, and Delta E-p for the Cu46Zr42Al7Gd5 BMG alloy with Kissinger equations are 340.7, 211.3, and 211.3 kJ/mol, respectively. These values with Ozawa equations are 334.8, 210.3, and 210.3 kJ/mol, respectively. The Cu46Zr45Al7Tb2 alloy presents the highest microhardness, HV 590, while the Cu46Zr43Al7Pr4 alloy presents the least, HV 479. The compressive strength (sigma(c.f.)) of the Cu(46)Zr(43)Al(7)Gd(4)BMG alloy is higher than that of the Cu46Zr43Al7Tb4 BMG alloy.
10.1007-s12598-011-0426-y	15	aging; strength; conductivity; electrical conductivity; electrical; mpa; treatment; strengthening; degrees; cu-; cold; precipitation; tensile strength; tensile; iacs	The aging characteristic of Cu-0.6Cr-0.15Zr-0.05Mg-0.02Si alloy containing trace rare earth yttrium was investigated. The results showed that Cu-0.6Cr-0.15Zr-0.05Mg-0.02Si alloy obtained good comprehensive performance after 80% rolling and then aging at 480 degrees C for 1 h; the hardness and electrical conductivity reached HV 150 and 85.5% IACS, respectively. Increasing aging temperature accelerated aging precipitation. The time for attaining peak hardness was postponed, the precipitates were finer (2-4 nm), and the interparticle spacing was shorter due to yttrium addition. The hardness and electrical conductivity of the Y-containing alloy after 80% deformation and then aging at 480 degrees C for 45 min reached HV 174 and 82.1% IACS, respectively.
10.1007-s12598-012-0492-9	-1		A pseudo-alloy PS45/CuAl8 composite coating was sprayed on steel substrate by high-velocity activated arc spraying (HVAA) process. Its sliding wear behavior at room temperature was evaluated by M-2000 wear tester. For comparison, a single CuAl8 coating was also prepared and tested under the same conditions. It is found that the pseudo-alloy composite coating consists of alpha-Cu and gamma-Ni metallic matrix phases together with homogenously distributed minor Al2O3, Cr2O3 oxide phases. Moreover, pseudo-alloy coating possesses much better sliding wear resistance than CuAl8 coating due to the enhanced hardness and microstructural homogenization. Fatigue wear and abrasive wear are responsible for the wear-down mechanism of the pseudo-alloy coating.
10.1007-s12598-015-0502-9	-1		High-strength Cu-3Ag-0.5Zr alloy plates were produced by multi-pass rolling in the temperature range of 500-800 A degrees C. An increase in strength was observed by rolling in the aforementioned range without significant loss in ductility. All the rolled samples show higher strength than solution-treated and aged samples. The maximum strength was observed for plates rolled at 500 A degrees C with a yield strength and ultimate tensile strength of 311 and 385 MPa, respectively, and retaining a ductility of 23 %. Transmission electron microscopy (TEM) studies showed uniform distribution of fine silver precipitates and high dislocation density in the rolled samples. Nevertheless, the size of precipitates and dislocation density varied with the rolling temperature. The superior strength achieved in the rolled samples is attributed to grain refinement, dislocation strengthening, and precipitation hardening. This method can be employed to produce high-strength plates of precipitation hardenable copper alloys.
10.1007-s12598-016-0843-z	17	wear; composites; coating; friction; composite; coatings; surface; tribological; properties; wear resistance; resistance; powder; sliding; matrix; wear rate	Cu-Cr-W composite coatings were prepared by mechanical alloying (MA) method using different powder ratios, rotational speeds and milling time. The microstructures and chemical compositions of as-synthesized coatings were analyzed by scanning electron microscopy (SEM) and energy-dispersive spectroscopy (EDS). Phases of ball-milled powders were identified by X-ray diffraction (XRD). The results indicate that the coating fabricated with powder ratio of 40 wt% Cu-Cr-W has better surface and cross-sectional microstructures and higher microhardness. The comparisons of cross-sectional microstructures of the coatings fabricated at different rotational speeds suggest that rotational speed of 300 r center dot min(-1) is the optimal for fabrication the coating, and the optimal milling time for the formation of coating is 7 h . The results of microhardness test show that the hardness of the substrate is largely improved because of the as-fabricated coatings. The results of the friction and wear tests indicate that the wear resistance of the copper substrate is improved after the deposition of Cu-Cr-W coating on it. The coating fabricated for 7 h exhibits the lowest friction coefficient, indicating its favorable friction and wear resistance. The formation mechanism of the coating was elucidated. According to the investigations in this work, the Cu-Cr-W coating fabricated by MA method is considered to be effective to reinforce the copper substrate.
10.1007-s12598-018-1169-9	-1		The coarsening behavior of (Ni, Co)(2)Si particles in Cu-Ni-Co-Si alloy was investigated by experimental observations and coarsening kinetics calculations when aged at 450, 500, 550 and 600 degrees C for different durations. The results show that the critical particle radius for coherence mismatch is found to be 10.3 nm, and particles larger than 25 nm are generally semi-coherent. The relationship of (Ni, Co)(2)Si particles size and aging time follows Lifshitz, Slyosov and Wagner (LSW) theory. The particle size distributions fit well to the LSW theoretical distribution. The activation energy for (Ni, Co)(2)Si coarsening is accurately determined to be (216.21 +/- 5.18) kJ.mol(-1) when considering the effect of temperature on the solution concentrations in matrix. The coarsening of (Ni, Co)(2)Si particles in Cu-Ni-Co-Si alloy is controlled by diffusion of Ni, Co and Si in Cu matrix. The growth of particles for long durations suggests that vacancies can be trapped within the structure for long time despite their mobility.
10.1007-s12598-019-01287-2	16	wear; composite; composites; powders; milling; particles; powder; wt; sliding; friction; hardness; matrix; mechanical; surface; properties	Cu matrix composite materials reinforced with B4C particle at four different contents (1.5 wt%, 3.0 wt%, 4.5 wt% and 6.0 wt%) and also CuAl matrix composites with 13 wt% Al reinforced with B4C particle at four different contents (1.5 wt%, 3.0 wt%, 4.5 wt% and 6.0 wt%) were fabricated by hot pressing (HP) and a powder metallurgy (PM) process. Experimental samples were produced by keeping them at 880 degrees C at the constant pressure of 2.3x10(8) Pa for 6 min. The density, microstructure and mechanical properties of the produced samples were examined. The microstructure and phase examinations were carried out by scanning electron microscope (SEM) and optical microscope (OM), energy-dispersive spectrometer (EDS) and X-ray diffractometer (XRD) analysis. The hardness measurements, three-point bending test and impact test were conducted to determine the mechanical properties. As a result of the examinations, it was observed that the relative density values decreased with the increasing content of B4C and provided a relatively effective bonding. Moreover, it was homogeneously distributed in the produced specimens. Consequently, there was a considerable increase in the hardness and the bending strength of CuAl matrix specimens with Al addition.
10.1007-s12598-020-01699-5	15	aging; strength; conductivity; electrical conductivity; electrical; mpa; treatment; strengthening; degrees; cu-; cold; precipitation; tensile strength; tensile; iacs	The tradeoff between the strength and the fracture elongation in the high-strength Cu-Ni-Si alloy became a hot research topic recently. Cu-Ni-Si-(Ti) alloys were fabricated in a vacuum induction melting furnace to study the effects of titanium on the microstructure and mechanical properties of Cu-Ni-Si alloys with different thermo-mechanical treatments. After homogenization at 900 degrees C for 4 h, hot-rolled by 80%, solution treatment at 970 degrees C for 2 h, cold-rolled by 50%, and finally aged at 450 degrees C for 180 min, the studied Cu-10Ni-Si-2Ti alloy achieved the hardness of HV 252.4, electrical conductivity of 23.6% IACS, tensile strength of 764.4 MPa, yield strength of 622.26 MPa, fracture elongation of 10.4%, and strength-elongation product of 7.95 GPa%, which are less than those of the studied Cu-10Ni-2Si alloy. The addition of Ti contributed to refining the microstructure, suppressing the decreasing trend in mechanical properties after peak hardening, and arousing a primary substructure strengthening mechanism rather than the precipitation strengthening in Cu-Ni-Si alloys. These findings provide essential understandings of the effects of the Ti on Cu-Ni-Si system alloys, and the designed Cu-Ni-Si alloys with high-strength and fracture elongation could fulfill some requirements of the electronic and electrical industry.
10.1007-s12598-023-02353-6	-1		The Cu-based shape memory alloy (SMA) with highly oriented columnar crystals is an ideal candidate for the commercial application, especially the ones obtained through rapid cooling via additive manufacturing method. In this work, Cu71Al18Mn11 (at%) shape memory alloy with strong <001> texture columnar grains was successfully prepared by selective laser melting (SLM). An L-27(3(13)) orthogonal array was designed to systematically investigate the effects of laser power, scanning speed, scanning spacing, layer thickness and their interactions on the forming quality of Cu71Al18Mn11 alloys. Cu71Al18Mn11 alloys with density of 7.3204 g center dot cm(-3) and relative density of 99.18% were successfully prepared when the laser power, scanning speed, scanning distance and layer thickness were 240 W, 1000 mm center dot s(-1), 0.11 mm and 25 mu m, the transformation onset temperature (M-s), martensite phase transformation termination temperature (M-f), austenite phase transformation onset temperature (A(s)) and austenite phase transformation termination temperature (A(f)) are -21.84, -26.04, -15.75 and -12.36 degrees C, respectively. The compression strength and fracture strain along the building direction (BD) were significantly superior to the scanning direction (SD), while the superelasticity of compression along the SD reached 2.50%, which was better than that of 2.32% along BD. The mechanical property and superelasticity anisotropy due to the formation of columnar grains and texture were discussed. This study shows that SLM is a proposed method for the preparation of Cu-Al-Mn SMAs with high superelasticity, which provides a new strategy for enhancing the shape memory alloy superelasticity.
10.1007-s12598-023-02544-1	-1		The volume fractions and morphology of precipitates in precipitation-strengthened Cu-Ti alloys, which precipitate mainly as continuous and discontinuous precipitates, are important for the application of the alloy. This study employed hardness and electrical conductivity tests, transmission electron microscopy (TEM), atom probe tomography (APT), and first-principles calculations to demonstrate that the addition of Mg is effective for accelerating nanosized continuous beta '-Cu4Ti precipitation as well as for suppressing the precipitation of coarse lamellar discontinuous beta-Cu4Ti precipitates along the grain boundaries, resulting in Cu-Ti alloys with high yield strength and good electrical conductivity. The results showed that the continuous precipitation of beta '-Cu4Ti was accelerated by the Mg additions, which reduced the supersaturation of the matrix, thereby reducing the chemical driving force for the discontinuous precipitates. On the other hand, Mg additions increased the mismatch between the discontinuous beta-Cu4Ti precipitates and matrix, decreased the nucleation rate of the discontinuous precipitates, and increased the spacing of the discontinuous precipitation layer, resulting in a lower growth rate of the discontinuous precipitates. Therefore, the addition of Mg to Cu-Ti alloys enhances the strength and improves the resistance to over-ageing.
10.1007-s12598-024-02782-x	-1		Strengthening interface bonding between boron nitride nanosheets (BNNS) and copper matrix is an essential prerequisite for exploiting a new generation of copper matrix composites (CMCs) with high strength and wear resistance. Herein, BNNS/Cu composites were fabricated by the powder metallurgy route, matrix-alloying (adding 1.0 wt% Ti) strategy was adopted to improve the interfacial wettability and strengthen interface adhesion. A typical sandwich-like multiply interface structure involving TiN transition layers, BNNS and Cu matrix had been well constructed through the rational heat treatment (900 degrees C for 120 min). Additionally, nano-sized TiB whisker was in situ formed in the vicinity of the interface, it had linked the BNNS-Cu-TiN multiply interface, which played a role of threading the needle and significantly strengthened the multi-interfaces bonding. This specific interface structure was finely characterized, and the formation mechanism of solid-state interfacial reaction feature was proposed. The results demonstrated that the ultimate tensile strength (UTS) of BNNS/Cu-(Ti)-900 degrees C increased from 248 to 530 MPa (increased by 114%), and the coefficient of friction (COF) decreased from 0.51 to 0.28 than pure Cu. This work highlights the importance of interface configuration design, which contributes to the development of CMCs with prominent comprehensive properties.
10.1007-s12598-024-02895-3	-1		Designing heterogeneous grain structure (HGS) has been proven to be an effective strategy for overcoming the strength-plasticity dilemma in copper and copper alloys. However, the construction of HGS in dispersion-strengthened copper (DSC) for enhancing strength-plasticity synergy remains challenging. Here, we proposed a novel method, multistep ball milling and reduction process followed by spark plasma sintering, to prepare DSC with an HGS to ameliorate the strength-plasticity dilemma in DSC. Micron- and nano-CuO and nano-Y2O3 powders were chosen as raw materials in this new method. The Cu-7 vol% Y2O3 composite, exhibiting a compressive yield strength of 438 MPa and a failure strain of 46.3%, exhibits a superior strength-plasticity tradeoff in comparison with other DSC materials. Systematic experiments indicate that the back-stress at the heterointerfaces between coarse grains and fine grains maybe not only raise the yield strength of Cu-Y2O3 composite, but also significantly enhance the strain hardening to increase the plasticity of the material. The new HGS designing route in this study offers a feasible pathway to develop DSC with a remarkable enhancement in strength and plasticity.
10.1007-s12598-025-03488-4	-1		Cu-Ni-P alloys combine excellent mechanical properties and electrical conductivity are considered the ideal materials for next-generation electronic components. In this study, we have identified a new mechanism for the crystallographic transformation of the precipitated in a Cu-0.96Ni-0.22P alloy, which may unravel the long-standing misunderstandings of the precipitation behavior in Cu-Ni-P alloys. The crystallographic and morphological evolution of two types of Ni2P precipitates found in this study was investigated in detail via transmission electron microscopy (TEM), aberration-corrected TEM (ACTEM), and atom probe tomography (APT), etc. The increase in aging temperature promoted the evolution of Ni2P phase from spherical to the disk-shaped, which can be regarded as a 5.6 degrees rotation along the [4040]Ni2P\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$${[40\overline{4 }0]}_{\text{Ni}_2\text{P}}$$\end{document} axis according to three-dimensional reconstruction results. The high-index (1232)Ni2P\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$${(12\overline{3 }\overline{2 })}_{\text{Ni}_2\text{P}}$$\end{document} face demonstrates a lower interfacial misfit after the transformation, which promotes the growth of both the (1232)Ni2P\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$${(12\overline{3 }\overline{2 })}_{\text{Ni}_2\text{P}}$$\end{document} and (4040)Ni2P\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$${(40\overline{4 }0)}_{\text{Ni}_2\text{P}}$$\end{document} faces, ultimately forming a disk-shaped phase. The gradual replacement of Cu atoms in the low-Ni transition layer with Ni atoms and (Ni, Cu)2P layer is formed, which accelerates the transformation of the disk-shaped Ni2P phase. This work is essential for promoting the microstructural design of Cu-Ni-P systems and provides new insights into the properties control in Cu-Ni-P alloys. Cu-Ni-P(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic), (sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic).(sic)(sic)(sic)(sic)Cu-0.96Ni-0.22P(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic), (sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)Cu-Ni-P (sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic).(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(TEM),(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(ACTEM)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(APT)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)Ni2P(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic).(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)Ni2P(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic), (sic)(sic)(sic)(sic)Ni2P(sic)(sic)(sic)(sic)(sic)(sic)(sic) [4040]Ni2P\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$${[40\overline{4 }0]}_{\text{Ni}_2\text{P}}$$\end{document} (sic)(sic)(sic)(sic)5.6 degrees(sic)(sic)(sic)(sic).(sic)(sic)(sic)(sic) (1232)Ni2P\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$${(12\overline{3 }\overline{2 })}_{\text{Ni}_2\text{P}}$$\end{document} (sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic), (sic)(sic)(sic)(sic)(sic) (1232)Ni2P\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$${(12\overline{3 }\overline{2 })}_{\text{Ni}_2\text{P}}$$\end{document} (sic)(sic) (4040)Ni2P\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$${(40\overline{4 }0)}_{\text{Ni}_2\text{P}}$$\end{document} (sic)(sic)(sic)(sic)(sic)(sic), (sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic).(sic)Ni(sic)(sic)(sic)(sic)(sic)Cu(sic)(sic)(sic)(sic)(sic)Ni(sic)(sic)(sic)(sic), (sic)(sic)(sic)(sic)(Ni, Cu)2P(sic), (sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic) Ni2P (sic)(sic)(sic)(sic)(sic)(sic)(sic).(sic)(sic)(sic)(sic)(sic)(sic)(sic)Cu-Ni-P(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic).
10.1007-s12613-010-0212-0	4	transformation; martensite; martensitic; phase; shape; beta; memory; shape memory; temperature; temperatures; martensitic transformation; gamma; transformation temperatures; effect; thermal	The influences of 2.5wt% Mn addition on the microstructure and mechanical properties of the Cu-11.9wt%Al-3.8wt%Ni shape memory alloy (SMA) were studied by means of scanning electron microscopy (SEM), transmission electron microscopy (TEM), and differential scanning calorimeter (DSC). The experimental results show that Mn addition influences considerably the austenite-martensite transformation temperatures and the kind of martensite in the Cu-Al-Ni alloy. The martensitic transformation changes from a mixed beta(1) -> beta(1)'+gamma(1)' transformation to a single beta(1) -> beta(1)' martensite transformation together with a decrease in transformation temperatures. In addition, the observations reveal that the grain size of the Cu-Al-Ni alloy can be controlled with the addition of 2.5wt% Mn and thus its mechanical properties can be enhanced. The Cu-Al-Ni-Mn alloy exhibits better mechanical properties with the high ultimate compression strength and ductility of 952 MPa and 15%, respectively. These improvements are attributed to a decrease in grain size. However, the hardness decreases from HV 230 to HV 140 with the Mn addition.
10.1007-s12613-010-0311-y	-1		Starting from the quaternary Cu(47)Ti(34)Zr(11)Ni(8) alloy, the compositional dependence of thermal and elastic properties of Cu-Ti-Zr-Ni alloys was systematically investigated. Quaternary Cu-Ti-Zr-Ni alloys can be cast directly from the melt into copper molds to form fully amorphous strips or rods with the thickness of 3-6 mm. The evidence of the amorphous nature of the cast rods was provided by X-ray spectra. The measured glass transition temperature (T(g)) and crystallization temperature (T(x)) were obtained for the alloys using differential scanning calorimetry (DSC) at the heating rate of 20 K/s. In the results, the differences between the glass temperature and the crystallization temperature (Delta T(x)=T(x)-T(g)) are measured with values ranging up to 33-55 K. The reduced glass transition temperature (T(rg)), which is the ratio of the glass temperature to the liquidus temperature (T(1)), is often used as an indication of the glass-forming ability of metallic alloys. For the present Cu-Ti-Zr-Ni alloys, this ratio is typically in the range of 0.5838-0.5959, characteristic of metallic alloys with good glass-forming ability. The elastic constants for several selected alloys were measured using ultrasonic methods. The values of the elastic shear modulus, bulk modulus, and Poisson's ratio were also given.
10.1007-s12613-010-0366-9	-1		Microstructures have profound effects on the hardness and strength of Cu-Cr alloys. The microstructures of a Cu-Cr alloy cast in a water-cooled copper mold were studied in the present work. The scanning electron microscopy (SEM) results show that there are the copper matrix saturated with chromium, spherical precipitates of chromium separated from liquid phase during cooling before the initiation of solidification, and a eutectic phase in grain boundary areas. To investigate the effect of age-hardening treatment on the microstructures and properties of the material, some samples were subsequently age-hardened in a salt bath and investigated by transmission electron microscopy (TEM). The results show that coherent precipitates with the diameter of 11 nm are detectable in the samples before and after the age-hardening stage. Of course, the volume fraction of coherent precipitates is higher after the aging process.
10.1007-s12613-011-0458-1	4	transformation; martensite; martensitic; phase; shape; beta; memory; shape memory; temperature; temperatures; martensitic transformation; gamma; transformation temperatures; effect; thermal	The influence of aging on the microstructure and mechanical properties of Cu-11.6wt%Al-3.9wt%Ni-2.5wt%Mn shape memory alloy (SMA) was studied by means of scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray diffractometer, and differential scanning calorimeter (DSC). Experimental results show that bainite, gamma(2), and alpha phase precipitates occur with the aging effect in the alloy. After aging at 300dgC, the bainitic precipitates appear at the early stages of aging, while the precipitates of gamma(2) phase are observed for a longer aging time. When the aging temperature increases, the bainite gradually evolves into gamma(2) phase and equilibrium alpha phase (bcc) precipitates from the remaining parent phase. Thus, the bainite, gamma(2), and alpha phases appear, while the martensite phase disappears progressively in the alloy. The bainitic precipitates decrease the reverse transformation temperature while the gamma(2) phase precipitates increase these temperatures with a decrease of solute content in the retained parent phase. On the other hand, these precipitations cause an increasing in hardness of the alloy.
10.1007-s12613-013-0767-7	-1		To improve the surface properties of magnesium alloys, a study was conducted on Cu-Zr-Al composite coatings on AZ91HP magnesium alloy by laser cladding. The influence of laser scanning speed on the microstructures and properties of the coatings was discussed. The coatings consist of amorphous phase, Cu8Zr3, and Cu10Zr7. With the increase of laser scanning speed, the amorphous phase content of the coatings increases and reaches 60.56wt% with the laser scanning speed of 2.0 m/min. Because of the influence of laser scanning speed on the amorphous and crystal phases, the coatings show the maximum elastic modulus, hardness, and wear resistance at the laser scanning speed of 1.0 m/min. At the laser scanning speed of 2.0 m/min, the coatings have the best corrosion resistance.
10.1007-s12613-014-1015-5	4	transformation; martensite; martensitic; phase; shape; beta; memory; shape memory; temperature; temperatures; martensitic transformation; gamma; transformation temperatures; effect; thermal	Different fragments of a hot-rolled and homogenized Cu-Zn-Al shape memory alloy (SMA) were subjected to thermal cycling by means of a differential scanning calorimetric (DSC) device. During thermal cycling, heating was performed at the same constant rate of increasing temperature while cooling was carried out at different rates of decreasing temperature. For each cooling rate, the temperature decreased in the same thermal interval. During each cooling stage, an exothermic peak (maximum) was observed on the DSC thermogram. This peak was associated with forward martensitic transformation. The DSC thermograms were analyzed with PROTEUS software: the critical martensitic transformation start (Ms) and finish (Mf) temperatures were determined by means of integral and tangent methods, and the dissipated heat was evaluated by the area between the corresponding maximum plot and a sigmoid baseline. The effects of the increase in cooling rate, assessed from a calorimetric viewpoint, consisted in the augmentation of the exothermic peak and the delay of direct martensitic transformation. The latter had the tendency to move to lower critical transformation temperatures. The martensite plates changed in morphology by becoming more oriented and by an augmenting in surface relief, which corresponded with the increase in cooling rate as observed by scanning electron microscopy (SEM) and atomic force microscopy (AFM).
10.1007-s12613-015-1185-9	-1		The effects of Ni addition and aging treatments on the microstructure and properties of a Cu-3Ti alloy were investigated. The microstructure and precipitation phases were characterized by X-ray diffraction, scanning electron microscopy, and transmission electron microscopy; the hardness, electrical conductivity, and elastic modulus of the resulting alloys were also tested. The results show that Ni addition increases the electrical conductivity and elastic modulus, but decreases the hardness of the aged Cu-3Ti alloy. Within the range of the experimentally investigated parameters, the optimal two-stage aging treatment for the Cu-3Ti-1Ni and Cu-3Ti-5Ni alloy was 300A degrees C for 2 h and 450A degrees C for 7 h . The hardness, electrical conductivity, and elastic modulus of the Cu-3Ti-1Ni alloy were HV 205, 18.2% IACS, and 146 GPa, respectively, whereas the hardness, electrical conductivity, and elastic modulus of the Cu-3Ti-5Ni alloy were HV 187, 31.32% IACS, and 147 GPa, respectively. Microstructural analyses revealed that beta'-Ni3Ti and beta'-Cu4Ti precipitate from the Cu matrix during aging of the Cu-3Ti-5Ni alloy and that some residual NiTi phase remains. The increased electrical conductivity is ascribed to the formation of NiTi, beta'-Ni3Ti, and beta'-Cu4Ti phases.
10.1007-s12613-016-1308-y	-1		In the paper, a melt extraction method was used to fabricate Cu-4Ni-14Al (wt%) fiber materials with diameters between 50 and 200 mu m. The fibers exhibited superelasticity and temperature-induced martensitic transformation. The microstructures and superelasticity behavior of the fibers were studied via scanning electron microscopy (SEM) and a dynamic mechanical analyzer (DMA), respectively. Appropriate heat treatment further improves the plasticity of Cu-based alloys. The serration behavior observed during the loading process is due to the multiple martensite phase transformation.
10.1007-s12613-016-1367-0	-1		Al2O3 dispersion copper alloy powder was prepared by internal oxidation, and three consolidation methods-high-velocity compaction (HVC), hot pressing (HP), and hot extrusion (HE)-were used to prepare Al2O3 dispersion-strengthened copper (Cu-Al2O3) alloys. The microstructures and properties of these alloys were investigated and compared. The results show that the alloys prepared by the HP and HE methods exhibited the coarsest and finest grain sizes, respectively. The alloy prepared by the HVC method exhibited the lowest relative density (98.3% vs. 99.5% for HP and 100% for HE), which resulted in the lowest electrical conductivity (81% IACS vs. 86% IACS for HP and 87% IACS for HE). However, this alloy also exhibited the highest hardness (77 HRB vs. 69 HRB for HP and 70 HRB for HE), the highest compressive strength (443 MPa vs. 386 MPa for HP and 378 MPa for HE), and the best hardness retention among the investigated alloys. The results illustrate that the alloy prepared by the HVC method exhibits high softening temperature and good mechanical properties at high temperatures, which imply long service life when used as spot-welding electrodes.
10.1007-s12613-017-1381-x	-1		Powder metallurgical Cu-Ti alloys with different titanium additions produced by hot pressing were characterized by optical microscopy, scanning electron microscopy, X-ray diffraction analysis, and hardness, wear and bending tests. The addition of titanium to copper caused the formation of different intermetallic layers around titanium particles. The titanium content of the intermetallics decreased from the center of the particle to the copper matrix. The hardness, wear resistance, and bending strength of the materials increased with increasing Ti content, whereas strain in the bending test decreased. Worn surface analyses showed that different wear mechanisms were active during the wear test of specimens with different chemical compositions. Changes in the properties of the materials with titanium addition were explained by the high hardness of different Cu-Ti intermetallic phases.
10.1007-s12613-017-1495-1	16	wear; composite; composites; powders; milling; particles; powder; wt; sliding; friction; hardness; matrix; mechanical; surface; properties	The main objective of this paper was to fabricate Cu10Sn5Ni alloy and its composites reinforced with various contents of Si3N4 particles (5wt%, 10wt%, and 15wt%) and to investigate their dry sliding wear behavior using a pin-on-disk tribometer. Microstructural examinations of the specimens revealed a uniform dispersion of Si3N4 particles in the copper matrix. Wear experiments were performed for all combinations of parameters, such as load (10, 20, and 30 N), sliding distance (500, 1000, and 1500 m), and sliding velocity (1, 2, and 3 m/s), for the alloy and the composites. The results revealed that wear rate increased with increasing load and increasing sliding distance, whereas the wear rate decreased and then increased with increasing sliding velocity. The primary wear mechanism encountered at low loads was mild adhesive wear, whereas that at high loads was severe delamination wear. An oxide layer was formed at low velocities, whereas a combination of shear and plastic deformation occurred at high velocities. The mechanism at short sliding distances was ploughing action of Si3N4 particles, which act as protrusions; by contrast, at long sliding distances, direct metal-metal contact occurred. Among the investigated samples, the Cu/10wt% Si3N4 composite exhibited the best wear resistance at a load of 10 N, a velocity of 2 m/s, and a sliding distance of 500 m.
10.1007-s12613-017-1524-0	16	wear; composite; composites; powders; milling; particles; powder; wt; sliding; friction; hardness; matrix; mechanical; surface; properties	The effect of alumina nanoparticle addition on the microstructure and tribological properties of a CuCrW alloy was investigated in this work. Mechanical alloying was carried out in a satellite ball mill. The tribological properties of the samples were evaluated using pin-on-disk wear tests with different pins (alumina, tungsten carbide, and steel pins). The results indicated that the tungsten carbide pin had a lower coefficient of friction than the alumina and steel pins because of its high hardness and low surface roughness. In addition, when the sliding rate was decreased, the weight-loss rate increased. The existence of alumina nanoparticles in the nanocomposite led to a lower weight-loss rate and to a change in the wear mechanism from adhesive to abrasive.
10.1007-s12613-019-1886-6	-1		Cu-Zn-Sn shape memory alloys (SMAs) with an average composition of 56.0at%, 36.1at%, and 7.9at% for Cu, Zn, and Sn, respectively, were successfully fabricated via an electrodeposition-annealing route. The produced SMAs were assessed for shape memory response in terms of percent displacement (martensite phase recovery) by subjecting the ternary alloys to flame tests and subsequently characterizing them via differential scanning calorimetry (DSC), optical microscopy, scanning electron microscopy in conjunction with energy- dispersive spectroscopy (SEM-EDS), and X-ray diffraction (XRD) analysis. The flame tests showed that the highest displacement was ca. 93%, with average austenite and martensitic start transformation temperature of 225 degrees C and 222 degrees C, respectively. XRD analysis revealed that the intermetallic phases responsible for the observed shape memory properties have substitutional Zn in the lattice occupied by Cu and Sn, leading to the formation of Cu(Zn,Sn) and Cu-6(Zn,Sn)(5) variants. The formation of these variants was attributed to the faster interdiffusion of Cu into Sn, driven by an activation energy of 34.82 kJ center dot mol(-1). Five cycles of repeated torching-annealing revealed an essentially constant shape memory response, suggesting that the fabricated SMAs were consistent and sufficiently reliable for their intended service application.
10.1007-s12613-019-1889-3	-1		Tungsten nanoparticle-strengthened Cu composites were prepared from nanopowder synthesized by a sol-gel method and in-situ hydrogen reduction. The tungsten particles in the Cu matrix were well-dispersed with an average size of approximately 100-200 nm. The addition of nanosized W particles remarkably improves the mechanical properties, while the electrical conductivity did not substantially decrease. The Cu-W composite with 6wt% W has the most comprehensive properties with an ultimate strength of 310 MPa, yield strength of 238 MPa, hardness of HV 108 and electrical conductivity of 90% IACS. The enhanced mechanical property and only a small loss of electrical conductivity demonstrate the potential of this new strategy to prepare W nanoparticle-strengthened Cu composites.
10.1007-s12613-019-1894-6	-1		The machine-learning approach was investigated to predict the mechanical properties of Cu-Al alloys manufactured using the powder metallurgy technique to increase the rate of fabrication and characterization of new materials and provide physical insights into their properties. Six algorithms were used to construct the prediction models, with chemical composition and porosity of the compacts chosen as the descriptors. The results show that the sequential minimal optimization algorithm for support vector regression with a puk kernel (SMOreg/puk) model demonstrated the best prediction ability. Specifically, its predictions exhibited the highest correlation coefficient and lowest error among the predictions of the six models. The SMOreg/puk model was subsequently applied to predict the tensile strength and hardness of Cu-Al alloys and provide guidance for composition design to achieve the expected values. With the guidance of the SMOreg/puk model, Cu-12Al-6Ni alloy with a tensile strength (390 MPa) and hardness (HB 139) that reached the expected values was developed.
10.1007-s12613-020-2176-z	16	wear; composite; composites; powders; milling; particles; powder; wt; sliding; friction; hardness; matrix; mechanical; surface; properties	Nano-sized silicon carbide (SiC: 0wt%, 1wt%, 2wt%, 4wt%, and 8wt%) reinforced copper (Cu) matrix nanocomposites were manufactured, pressed, and sintered at 775 and 875 degrees C in an argon atmosphere. X-ray diffraction (XRD) and scanning electron microscopy were performed to characterize the microstructural evolution. The density, thermal expansion, mechanical, and electrical properties were studied. XRD analyses showed that with increasing SiC content, the microstrain and dislocation density increased, while the crystal size decreased. The coefficient of thermal expansion (CTE) of the nanocomposites was less than that of the Cu matrix. The improvement in the CTE with increasing sintering temperature may be because of densification of the microstructure. Moreover, the mechanical properties of these nanocomposites showed noticeable enhancements with the addition of SiC and sintering temperatures, where the microhardness and apparent strengthening efficiency of nanocomposites containing 8wt% SiC and sintered at 875 degrees C were 958.7 MPa and 1.07 vol%(-1), respectively. The electrical conductivity of the sample slightly decreased with additional SiC and increased with sintering temperature. The prepared Cu/SiC nanocomposites possessed good electrical conductivity, high thermal stability, and excellent mechanical properties.
10.1007-s12613-021-2276-4	-1		On the interface of the Cu-Al composite plate from horizontal continuous casting, the eutectic microstructure layer thickness accounts for more than 90% of the total interface thickness, and the deformation in rolling forming plays an important role in the quality of the composite plate. The eutectic microstructure material on the interface of the Cu-Al composite plate was prepared by changing the cooling rate of ingot solidification and the deformation in hot compression was investigated. The results show that when the deformation temperature is over 300 degrees C, the softening effect of dynamic recrystallization of alpha-Al is greater than the hardening effect, and uniform plastic deformation of eutectic microstructure is caused. The constitutive equation of flow stress in the eutectic microstructure layer was established by Arrhenius hyperbolic-sine mathematics model, providing a reliable theoretical basis for the deformation of the Cu-Al composite plate.
10.1007-s12613-022-2412-9	-1		Silver-based alloys are significant light-load electrical contact materials (ECMs). The trade-off between mechanical properties and electrical conductivity is always an important issue for the development of silver-based ECMs. In this paper, we proposed an idea for the regulation of the mechanical properties and the electrical conductivity of Ag-11.40Cu-0.66Ni-0.05Ce (wt%) alloy using in-situ composite fiber-reinforcement. The alloy was processed using rolling, heat treatment, and heavy drawing, the strength and electrical conductivity were tested at different deformation stages, and the microstructures during deformation were observed using field emission scanning electron microscope (FESEM), transmission electron microscope (TEM) and electron backscatter diffraction (EBSD). The results show that the method proposed in this paper can achieve the preparation of in-situ composite fiber-reinforced Ag-Cu-Ni-Ce alloys. After the heavy deformation drawing, the room temperature Vickers hardness of the as-cast alloy increased from HV 81.6 to HV 169.3, and the electrical conductivity improved from 74.3% IACS (IACS, i.e., international annealed copper standard) to 78.6% IACS. As the deformation increases, the alloy strength displays two different strengthening mechanisms, and the electrical conductivity has three stages of change. This research provides a new idea for the comprehensive performance control of high-performance silver-based ECMs.
10.1007-s12613-022-2479-3	-1		It is difficult to rapidly design the process parameters of copper alloys by using the traditional trial-and-error method and simultaneously improve the conflicting mechanical and electrical properties. The purpose of this work is to develop a new type of Cu-Ni-Co-Si alloy saving scarce and expensive Co element, in which the Co content is less than half of the lower limit in ASTM standard C70350 alloy, while the properties are as the same level as C70350 alloy. Here we adopted a strategy combining Bayesian optimization machine learning and experimental iteration and quickly designed the secondary deformation-aging parameters (cold rolling deformation 90%, aging temperature 450 degrees C, and aging time 1.25 h) of the new copper alloy with only 32 experiments (27 basic sample data acquisition experiments and 5 iteration experiments), which broke through the barrier of low efficiency and high cost of trial-and-error design of deformation-aging parameters in precipitation strengthened copper alloy. The experimental hardness, tensile strength, and electrical conductivity of the new copper alloy are HV (285 +/- 4), (872 +/- 3) MPa, and (44.2 +/- 0.7)% IACS (international annealed copper standard), reaching the property level of the commercial lead frame C70350 alloy. This work provides a new idea for the rapid design of material process parameters and the simultaneous improvement of mechanical and electrical properties.
10.1007-s12613-024-2870-3	15	aging; strength; conductivity; electrical conductivity; electrical; mpa; treatment; strengthening; degrees; cu-; cold; precipitation; tensile strength; tensile; iacs	Solid solution-strengthened copper alloys have the advantages of a simple composition and manufacturing process, high mechanical and electrical comprehensive performances, and low cost; thus, they are widely used in high-speed rail contact wires, electronic component connectors, and other devices. Overcoming the contradiction between low alloying and high performance is an important challenge in the development of solid solution-strengthened copper alloys. Taking the typical solid solution-strengthened alloy Cu-4Zn-1Sn as the research object, we proposed using the element In to replace Zn and Sn to achieve low alloying in this work. Two new alloys, Cu-1.5Zn-1Sn-0.4In and Cu-1.5Zn-0.9Sn-0.6In, were designed and prepared. The total weight percentage content of alloying elements decreased by 43% and 41%, respectively, while the product of ultimate tensile strength (UTS) and electrical conductivity (EC) of the annealed state increased by 14% and 15%. After cold rolling with a 90% reduction, the UTS of the two new alloys reached 576 and 627 MPa, respectively, the EC was 44.9%IACS and 42.0%IACS, and the product of UTS and EC (UTS x EC) was 97% and 99% higher than that of the annealed state alloy. The dislocations proliferated greatly in cold-rolled alloys, and the strengthening effects of dislocations reached 332 and 356 MPa, respectively, which is the main reason for the considerable improvement in mechanical properties.
10.1007-s12613-024-2969-6	-1		Simultaneously achieving high strength and high electrical conductivity in Cu-Ni-Si alloys pose a significant challenge, which greatly constrains its applications in the electronics industry. This paper offers a new pathway to improve properties, by preparation of nanometer lamellar discontinuous precipitates (DPs) arranged with the approximate same direction through a combination of deformation-aging and cold rolling process. The strengthening effect is primarily attributed to nanometer-lamellar DPs strengthening and dislocation strengthening mechanism. The accumulation of dislocations at the interface between nanometer lamellar DPs and matrix during cold deformation process can results in the decrease of dislocation density inside the matrix grains, leading to the acceptably slight reduction of electrical conductivity during cold rolling. The alloy exhibits an electrical conductivity of 45.32%IACS (international annealed copper standard, IACS), a tensile strength of 882.67 MPa, and a yield strength of 811.33 MPa by this method. This study can provide a guidance for the composition and microstructure design of a Cu-Ni-Si alloy in the future, by controlling the morphology and distribution of DPs.
10.1007-s12633-017-9578-1	-1		The growing demand for relatively inexpensive non-hazardous copper alloys with a good combination of electrical conductivity and high strength has led to increasing researches on Cu-Nb alloys for their excellent predictions over Cu-Be alloys. Cu-2vol.% Nb was produced using spark plasma sintering and the effect of the additive on its electrical conductivity, densification, hardness, corrosion resistance and wear resistance were investigated. It was observed that the additive improved the electrical conductivity of Cu powder from 0.28 to 5.89 S/m within 19-406 degrees C. Relative densities of 97.08% for Cu-2vol.% Nb and 97.33% for pure Cu were obtained at 600 degrees C, while at 650 degrees C, they were 96.08 and 96.82% respectively. The microhardness values were 77 and 72 HV(0.1) at 600 degrees C, while at 650 degrees C, they were 83 and 66 HV(0.1) for Cu-2vol.% Nb and pure Cu respectively. The corrosion potential of Cu-2vol.% Nb was noble with a lower anodic current density, suggesting better corrosion resistance at 600 degrees C. Cu-2vol.% Nb showed a better wear resistance at 600 degrees C and an improved electrical conductivity at 650 degrees C.
10.1007-s12633-018-9835-y	16	wear; composite; composites; powders; milling; particles; powder; wt; sliding; friction; hardness; matrix; mechanical; surface; properties	In this investigation, the influence of cryogenic treatment on the tribological properties of Cu-Be2 alloy was investigated. Deep cryogenic treatment and shallow cryogenic treatment were applied to Cu-Be2 alloy. As-received (AR), shallow cryogenic treated (SCT) and deep cryogenic treated (DCT) Cu-Be2 alloy were used as pin material. AISI 4140 alloy steel hardened to 513 HV was used as disc. Wear test was carried out using pin-on-disc wear test set-up and the wear tracks were examined using Scanning Electron Microscope. Wear rate and coefficient of friction of the cryogenic treated sample were lower than that of the as-received sample. Adhesive wear, plastic deformation and delamination of asperities were found to be the principal mechanism in the wear characteristics on the as-received as well as the cryogenic treated samples.
10.1007-s12633-018-9848-6	16	wear; composite; composites; powders; milling; particles; powder; wt; sliding; friction; hardness; matrix; mechanical; surface; properties	The objective is to fabricate Cu-10Sn alloy and its composites reinforced with varying wt% of SiC (5, 10 and 15) to investigate its dry sliding wear behaviour. Microstructural analysis for composites revealed well dispersed SiC particles within matrix except for 15 wt% SiC composite, where agglomeration took place. Amongst all composites and alloy, 10 wt% of SiC composite had better hardness (144 HV). The tribological analysis using Pin-on-Disc tribometer for all alloy and composites revealed increase in wear rate with increase in load and distance for all combinations of parameters (load, sliding distance, and sliding velocity). Worn surface analysis concluded that the wear rate decreased with increase in velocity for both 5 and 10 wt% SiC composite due to formation of Mechanically Mixed Layer. The composite with 10 wt% SiC showed enhanced wear resistance and hence can be used for tribological applications like bearings and bushes.
10.1007-s12633-020-00764-z	16	wear; composite; composites; powders; milling; particles; powder; wt; sliding; friction; hardness; matrix; mechanical; surface; properties	The center of attention of current research lies on utilizing E-waste cathode ray tube (CRT) glass as reinforcement to develop copper hybrid surface composites through friction stir processing route. Pure copper is taken as base material which is reinforced with different volume % of CRT glass (5, 10 & 15) and fixed amount (2%) of BN. The particle size of the reinforced CRT and BN particles are 30 mu m and 10 mu m respectively. The developed surface composite was characterized for microstructure through optical microscope and scanning electron microscope, density, micro hardness, tensile properties and wears behavior. The analysis confirms the presence of reinforcements in the matrix and also evidence for recrystallization. Density of the MMC is found decreasing while the hardness increases with addition of CRT & BN. The tensile and yield strength of unprocessed Cu is superior to that of MMC whereas it enhanced with raise in reinforcement content. Wear resistance of Cu depicts incremental trend with respect to reinforcement's addition. Scanning electron microscope was used to understand the worn out surface morphology and wear mechanism. Corrosion results depict that increase in CRT addition decrease the corrosion current density of surface composite.
10.1007-s12633-023-02836-2	-1		Copper alloys with the main alloying elements Zn, Al, and Ni are well known for their impact, wear, and corrosion resistance. Different fabrication techniques and alloying elements can be used to modify the microstructure and properties. The effect of shell mould and permanent mould techniques on the microstructure, microhardness, and wear behaviour of high tensile brass and nickel aluminium bronze (RB031, RB032, and NAB) was investigated in this work. For permanent mould fabricated alloys, optical microscopic analysis revealed a homogeneous microstructure with fine grains. The RB032 alloy had a higher proportion of Mn5Si3 particles than the other two high tensile brasses (RB031 and RB032). In the case of NAB alloy, both fabrication techniques revealed similar phases composed of-phase,'phase, and intermetallic phases (I, II, III, and IV). Higher cooling rates in Permanent Moulded Cast alloys resulted in equiaxed structures, which were especially noticeable in RB032, which had 31% smaller grain size than Shell Moulded Cast alloy. RB032 (PM) microhardness values were 2.3% higher than Shell Moulded (SM), with RB032 exhibiting the highest increment. Permanent Moulded alloys outperformed Shell Moulded alloys in terms of friction and wear rate, with RB032 (PM) having 44% lower friction and 5.8% lower wear rate. The wear mechanisms differed, with RB031 exhibiting abrasive wear and RB032 and NAB(AB2) exhibiting adhesive wear.
10.1007-s12648-014-0480-z	4	transformation; martensite; martensitic; phase; shape; beta; memory; shape memory; temperature; temperatures; martensitic transformation; gamma; transformation temperatures; effect; thermal	Influence of the martensitic phase transformations on mechanical behavior of Cu-12.5 wt% Al shape memory alloy has been studied using microhardness measurements, differential thermal analysis, optical microscopy, X-ray diffraction and energy-dispersive X-ray spectroscopy. Results show that microstructure of the alloy is affected by both ageing temperature and time. Consequently, a change in alloy hardness has been observed. It has also been found that the ageing temperature is more effective on both alloy microstructure and hardness than ageing time. It is worth noting that ageing of the alloy sample at 450 degrees C for 12 h has doubled its hardness compared with unaged sample.
10.1007-s12648-024-03421-y	-1		To create granular materials with exceptional magnetoresistance properties, immiscible alloys were ball-milled in RSP (rapid solidification processing) ribbon. A system based on copper (Cu-Co) has been investigated. For Cu-Co-Ti, a single supersaturated solid solution has been found. The addition of Ti to Cu-Co substantially increases its solid solubility. The evolution of phase (s) during rapid solidification, and mechanical alloying followed by isothermal annealing were characterized using various techniques including differential thermal analyzers, High-resolution transmission electron microscopy, and X-ray diffraction. This study extensively used the superconducting quantum interference device magnetometer to observe magnetic behavior. The Cu-Co-Ti alloy from the ball milling RSP ribbon process was annealed at 550 degrees C for 1 h to get the favorable combination of magnetic characteristics. An in-depth theoretical analysis of the magnetic properties was conducted through the application of the 'VAMPIRE' software package, employing Monte Carlo Simulation as the underlying methodology.
10.1007-s12666-008-0060-z	2	corrosion; surface; film; electrochemical; films; spectroscopy; layer; current; solution; potential; resistance; composition; x-ray; ions; showed	Cu-10Ni alloy is a standard material for seawater application. Under Indian scenario, where half of copper and whole of Ni (and Cu-Ni) requirement is met by imports, search for a cheaper substitute is obvious. An attempt has been made to develop a single-phased copper alloy containing 10 wt% Ni, 29 wt% Zn, up to 5 wt% Mn and 1 wt% Fe as a substitute to Cu-10wt% Ni-1wt% Fe alloy. Studies on Corrosion resistance of test alloys were carried out in synthetic seawater (ASTM D 114-75) by electro-chemical methods (cathodic and anodic polarization). Corrosion product film formed on alloy containing 5wt% Mn was characterized by SEM and XRD. A film of Cu(2)O was found to form on the surface of the alloy, which accords corrosion protection. The test alloys containing 29 wt% Zn and 3 or 5 wt% Mn have exhibited better corrosion resistance in synthetic seawater than Cu-10Ni alloy. The role of Mn and Zn addition has been discussed.
10.1007-s12666-009-0010-4	2	corrosion; surface; film; electrochemical; films; spectroscopy; layer; current; solution; potential; resistance; composition; x-ray; ions; showed	Cu-10 Ni alloy suffers from accelerated corrosion in sulphide-polluted seawater. New copper alloys containing 29% Zn, 10Ni and 3 or 5% Mn have been found to be more corrosion resistant than Cu-10Ni alloys in sulphide polluted synthetic seawater. The studies were carried out in synthetic seawater (ASTM D 114-75) and sulphide was added through Na(2)S (1 gpl approximate to 41ppm S(2-)). Testing was carried out using cathodic and anodic potentiodynamic polarization methods. Corrosion product film formed on the Cu-29Zn-10Ni-5Mn alloy in sulphide polluted synthetic seawater was characterized using SEM and XRD. The film was found to contain Cu(2)O, Cu(2)S, NiS and ZnS. Better corrosion resistance of new alloys as compared to that of Cu-10Ni alloy is attributed to formation of ZnS, a bad conductor, in the film and incorporation of Mn(3+) cations in Cu(2)O and Cu(2)S lattice.
10.1007-s12666-009-0036-7	-1		Cu-Zn alloy system with three different compositions has been chosen to study the time, temperature and composition dependence of the Diffusion Induced Grain boundary Migration (DIGM) in the temperature range of 277-427 degrees C. The grain boundary migration follows parabolic rate law as a function of time. The diffusivity, D-b alpha, was calculated from concentration-distance profile using growth rate, v. The activation energy for diffusion is found to be 101kJ/mol which is nearly half of the activation energy required for volume diffusion indicating that preferential grain boundary diffusion is more favorable than volume diffusion leading to grain boundary migration in Cu-Zn system.
10.1007-s12666-011-0094-5	16	wear; composite; composites; powders; milling; particles; powder; wt; sliding; friction; hardness; matrix; mechanical; surface; properties	Cu-8 (by %at) Cr-4 (by %at) Nb alloy with high strength and high thermal conductivity have received a lot of attention over the last decades due to promising role in space application of rocket combustion chamber of reusable launch vehicle. In the present work, the copper alloy synthesize in induction furnace by in situ reduction of Nb2O5 by aluminothermic process in presence of Cr in the premelted copper. The resultant cast product was characterised for hardness, optical, SEM, EDS and XRD analysis. It is possible to synthesise copper alloy with reproducible microstructures and an average hardness of 134 VHN. The precipitates of Cr2Nb showed moderate distribution in and around the grain boundaries of copper with precipitates size varying from 0.7 to 2.5 mu m.
10.1007-s12666-012-0209-7	13	clusters; atomic; glass; atoms; composition; dynamics; metallic; icosahedral; glasses; simulations; molecular; cu-zr; molecular dynamics; metallic glasses; structural	Cu based bulk metallic glasses (BMGs) are widely studied because of their high glass forming ability (GFA) and interesting combination of properties such as high strength coupled with good ductility and low cost. With these attributes, Cu based BMGs are being projected as promising materials for practical applications. The process of glass formation in metallic systems is a challenging task and alloys should be cooled from the liquid state at rates faster than a critical cooling rate (R-c) to resist crystallization. Interestingly, composition plays an important role in achieving easy glass formation, which is usually measured in terms of R-c. In the present work, attempt has been made to identify the composition for easy glass formation in Cu based quaternary system by theoretical approach . A GFA parameter P-HS, which is a product of enthalpy of chemical mixing (a dagger H-chem) and mismatch entropy normalized with Boltzmann's constant (a dagger S-sigma/k(B)) is used to identify the best glass forming composition in Cu-Zr-Ag-Hf system. Further, a new parameter P-HSS, which is a product of P-HS and configurational entropy (Delta S-config/R) is found to illustrate strong correlation with GFA. An attempt has also been made to correlate P-HSS parameter with critical diameters and R-c using reported data in Cu-Zr-Ag-Hf system.
10.1007-s12666-013-0360-9	16	wear; composite; composites; powders; milling; particles; powder; wt; sliding; friction; hardness; matrix; mechanical; surface; properties	In the present work, a set of Cu-based powder mixtures containing up to 6 wt% Cr has been processed through mechanical alloying for a range of milling times up to 96 h . The mixtures were processed in a ball mill with ball to powder ratio of 10:1 and the equal numbers of 1 and 2 cm balls. The processed powder mixtures were investigated by scanning electron microscope, optical microscopic equipped with image analyzer, X-ray diffraction technique and micro hardness in order to determine the particles morphology, distribution of chromium, mean crystallite size, lattice parameter and hardness after milling, respectively. Crystallite sizes were measured by Williamson-Hall method and lattice parameters were determined using an extrapolation function. Results show that the powder behavior varies with milling time, and powder composition.
10.1007-s12666-013-0376-1	4	transformation; martensite; martensitic; phase; shape; beta; memory; shape memory; temperature; temperatures; martensitic transformation; gamma; transformation temperatures; effect; thermal	In this study, the effects of Co content on the crystal structure, transformation temperatures and microstructure of Cu-Al-Co shape memory alloy system were investigated. It was found that Cu-Al-Co alloy system has also 18R type martensitic structure, which is commonly observed in copper-based systems. The transformation temperatures were found to be higher than 250 A degrees C and they do not show a linear increase or decrease with Co content. The microstructural examination revealed the presence of martensite phase and precipitates. It was realized that the size of precipitate increases with increasing Co content. It can be stated that the hardness increased with increasing Co content. All these results point out that increasing Co content increases the strength of Cu-Al-Co shape memory alloy system.
10.1007-s12666-015-0524-x	6	grain; deformation; strain; strength; dislocation; cu-; tensile; size; ecap; grain size; sfe; ductility; hardening; high; stress	In this study, ultra-fine grained (UFG) Cu-Zn tubes were produced by parallel tubular channel angular pressing (PTCAP) process and the effects of the number of passes on the microstructure, mechanical properties and fracture behavior were investigated. The results showed that the yield and the ultimate strengths of the processed UFG tube increased about four and two folds compared to the coarse grain counterparts due to grains refinement. The notable increase in the strength achieved after the first pass of the PTCAP process and further passes of the process only have a minor effect on the tube properties which may be due to the grain size saturation. However, the tube ductility reduced drastically after the PTCAP processing. Hardness of the PTCAP processed tube was increased compared to the annealed one according to Hall-Petch relationship which reports the hardness in terms of grain size. The strength, hardness and ductility were decreased after two passes PTCAP as a result of the formation of microvoids during the further straining through three passes. Microstructural investigations show a notable decrease in the grain size.
10.1007-s12666-015-0689-3	4	transformation; martensite; martensitic; phase; shape; beta; memory; shape memory; temperature; temperatures; martensitic transformation; gamma; transformation temperatures; effect; thermal	In the present study, an attempt has been made to study the effect of the proportion of the main alloying constituents in a Cu-Al-Mn alloy, which is a known shape memory material. Four compositions of the alloy with varying ratios of Al:Mn, varying from 1 to 4 [added to copper], were synthesized using the liquid metallurgy route. After appropriate heat treatment to induce shape memory behaviour, they were studied for microstructure, X-ray diffraction, hardness and transformation temperature in an attempt to understand the effect of the varying ratios of the major alloying constituents on the properties mentioned. With an increase in the Al:Mn ratio, increase in grain size as well as cast hardness were observed. On the other hand, an increase in percentage decrease in hardness was observed with increase in Al:Mn ratio. Increase in Al:Mn ratio also favoured formation of martensitic structure with less amount of retained austenite.
10.1007-s12666-017-1066-1	-1		Understanding the mechanical behavior of the key elements in alloys, at the nano scale leads to the design of optimum microstructure against fatigue failure. In the present study, low cycle fatigue simulations have been carried out on defect free single crystal Cu (face centered cubic) nano wire of size about 7.23 x 7.23 x 14.46 nm (aspect ratio of 2:1) at temperature 10 K by using molecular dynamics simulations. Yielding was found to be initiated from corners of the nano wire by forming stacking faults. It was observed that cyclic stress response of the model system depended on microstructure which was at the starting of reverse loading. Potential energy was used as a tool to investigate the fatigue deformation characteristics of the Cu nano wire. It was observed that the competition between hexagonal close packed atoms and disordered atoms [especially point defects, surface atoms and non-crystalline atoms (other than surface atoms)] governed the cyclic characteristics of the model system.
10.1007-s12666-017-1246-z	16	wear; composite; composites; powders; milling; particles; powder; wt; sliding; friction; hardness; matrix; mechanical; surface; properties	The objective of this work is to fabricate functionally graded unreinforced copper alloy (Cu-10Sn) and a Cu-10Sn/SiC composite ((out)100 x (in)70 x 100 mm) by horizontal centrifugal casting process and to investigate its mechanical and tribological properties. The microstructure and hardness was analysed along the radial direction of the castings; tensile test was conducted at both inner and outer zones. Microstructural evaluation of composite indicated that the reinforcement particles formed a gradient structure across the radial direction and maximum reinforcement concentration was found at the inner periphery. Hence maximum hardness (205 HV) was observed at this surface. Tensile test results showed that, the tensile strength at inner zone of composite was observed to be higher (248 MPa) compared to that of the outer zone and unreinforced alloy. As mechanical properties showed better results at inner periphery, dry sliding wear experiments were carried out on the inner periphery of composite using pin-on-disc tribometer. Process parameters such as load (10-30 N), sliding distance (500-1500 m) and sliding velocity (1-3 m/s) were analyzed by Taguchi L-27 orthogonal array. The influence of parameters on wear rate was analyzed by signal-to-noise ratio and analysis of variance. Analysis results revealed that load (54%) had the highest effect on wear rate followed by sliding distance (18.2%) and sliding velocity (3.7%). The wear rate of composite increased with load and sliding distance, but decreased with sliding velocity. Regression equation was developed and was validated by confirmatory experiment. Worn surface of composite was observed using scanning electron microscopy and transition of wear was observed at all extreme conditions.
10.1007-s12666-018-1312-1	-1		Despite of substantial advancement, the effect of grain boundary (GB) complexions on high temperature creep deformation process has not been fully understood. In this paper, we have studied the high temperature bending creep deformation of copper bicrystal with various GB complexions under different loads using molecular dynamics simulation. It has been found that specimen with normal kite GB complexion have better creep resistance properties when subjected to comparatively lower applied load. In case of monolayer Zr segregation, a drastic decrease in creep strength as well as creep plasticity is observed due to inhibition of GB migration. On the other hand, deviation between creep properties for specimen with split-kite GB complexion and split-kite bilayer Zr segregation GB complexion is minimal. Enhanced creep plasticity is observed in case of split-kite bilayer Zr segregation GB complexion, which is due to formation of interpenetrating icosahedral clusters in the necking region. Fracture in specimen with monolayer Zr segregation GB complexion has occurred by means of slip phenomenon at lower deformation load whereas amorphization and necking is observed at higher deformation load. In case of specimen with bilayer Zr segregation GB complexion, it is found that fracture has occurred through amorphization and necking at all deformation loads due to higher GB thickness.
10.1007-s12666-018-1384-y	-1		The present work describes a new route for the preparation of Cu-Al-Ni alloy strips via spray atomization and deposition route. The route consists of atomizing liquid Cu-Al-Ni alloy with a jet of argon gas in a closed chamber, at a pressure of 1MPa. The semi-solid Cu-Al-Ni droplets are subsequently collected on the steel substrate placed vertically below the liquid metal stream in the atomization chamber to form a three-dimensional preform. The deposit produced on the substrate contains 5% porosity. The microstructural details of the spray deposited Cu-Al-Ni strips explains particularly the presence of porosity, formation of splats during the flight of spray casting and the associated microstructural evolution in Cu-Al-Ni spray deposit are explained.
10.1007-s12666-018-1471-0	6	grain; deformation; strain; strength; dislocation; cu-; tensile; size; ecap; grain size; sfe; ductility; hardening; high; stress	In this paper, the deformation behavior of Cu20Ni20Al20Co20Fe20 high-entropy alloy-coated single-crystal Cu substrate which undergoes nanoindentation has been investigated under molecular dynamic simulation with embedded-atom method potential. The dynamic structural evolutions under nanoindentation are presented using centrosymmetry parameter analysis, common neighbor analysis and radial distribution function plots. In the initial level of nanoindentation, the interface deformation is greatly confronted by the confined V-shaped growth of the distorted structure. But the sudden discrete dislocation burst account for avalanche break-down in the interface layer, which further get influenced by the evolution of multiple dislocation nodes that is significantly governed by core spreading, extended misfit dislocation generation and relative rotation. In the meanwhile, the subsequent generation of dislocation locks, complicated multiple dislocation loops, dislocation junctions and limited cross-slip in wide stacking faults (SFs) hasten the work hardening and in turn slows down the deformation progress. On the other hand, the intermediate appearance of narrow SFs and slip bands significantly reduces the work hardening rate that increases the optimum fracture strain value of the specimen. Moreover, the overall increase in dislocation density and dislocation length leads to a significant growth in dislocation sources which leads to forest hardening in the later stage.
10.1007-s12666-018-1523-5	16	wear; composite; composites; powders; milling; particles; powder; wt; sliding; friction; hardness; matrix; mechanical; surface; properties	Centrifugally cast functionally graded Cu-11Ni-4Si/10wt% TiC composite of dimension Oout100xOin70x100mm was heat treated to enhance the mechanical and tribological characteristics. Samples from inner zone (9-15mm) were initially solution treated (850 degrees C/1h), water quenched, and aged at varying temperatures (450, 500, and 550 degrees C) and ageing time (4, 6 and 8h). The highest hardness (192 HV) displayed by the specimen aged at 550 degrees C/6h was chosen for dry sliding tribological studies performed at varying applied loads (10-30N), sliding velocities (1-3m/s) and sliding distances (500-1500m). An improvement of 65% was observed on comparing the micro-hardness values of heat-treated and non-heat-treated composites, while a decrease of 54.8% was observed on comparing the wear rate of heat-treated alloy and composite at optimum parameters. The wear rate increased with applied load, decreased initially and then increased with sliding distance and sliding velocity. Analysis of variance predicted applied load as the major influential parameter, followed by sliding distance and sliding velocity. Worn surface analysis revealed increase in delamination along with mild to severe wear transition with increase in applied load, and the formation of a mechanically mixed layer with increase in sliding velocity. This composite having high wear rate and hardness could be utilized for automotive load bearings, cylinder liners and brake drum applications.
10.1007-s12666-019-01579-2	8	hot; deformation; strain; strain rate; dynamic; hot deformation; recrystallization; dynamic recrystallization; flow; rate; flow stress; compression; constitutive; degrees; stress	Hot deformation tests of an upward continuous cast Cu-0.19Cr-0.1Ag were performed on a thermal simulation testing machine with various strain rates (0.01-10s(-1)) at different deformation temperatures (750-950 degrees C) to investigate the microstructural evolution of hot deformation and the softening mechanism. From the results, a flow stress reduction ratio diagram was constructed. The diagram was divided into four regions with different softening mechanisms according to the stress-strain curve. Dynamic recrystallization was accompanied by two nucleation mechanisms: continuous dynamic recrystallization (CDRX) and discontinuous dynamic recrystallization, and the effect of CDRX decreased with increasing strain rate.
10.1007-s12666-019-01807-9	16	wear; composite; composites; powders; milling; particles; powder; wt; sliding; friction; hardness; matrix; mechanical; surface; properties	Nowadays, corrosion of metals is a major problem faced by marine, chemical and automobile industries. Therefore, several researchers are taking efforts to develop composite coatings reinforced with nanoscale materials for high corrosion resistance. In the present work, graphene nanoplatelets (Gr) are incorporated with Cu-Ni matrix to fabricate Cu-Ni/Gr nanocomposite coatings by electro-co-deposition method. Also, the influence of the various concentrations of graphene nanoplatelets in the plating bath on the surface morphology, elemental composition, microstructure, crystallite size, lattice strain, microhardness, average friction coefficient, wear loss and corrosion resistance of these coatings have been studied. The study shows that the mechanical, tribological and corrosion properties of the coatings are enhanced with graphene nanoplatelets incorporation in Cu-Ni matrix. The measured microhardness for Cu-Ni/Gr (400 mg/L) nanocomposite coating increases by 44.17% compared to pure Cu-Ni coating. Also, immersion study indicates that the incorporation of graphene nanoplatelets stabilizes the corrosion potential and enhances the corrosion resistance.
10.1007-s12666-021-02235-4	-1		Recently, severe plastic deformation (SPD) is recognized as a very efficient processing technique for the fabrication of bulk nanostructured (ns)/ultrafine-grained materials. High-speed high-pressure torsion (HSHPT) process, an SPD method, is used as a novel approach to produce ultrafine grains in memory materials. The influence of HSHPT process variables on some Cu-based shape memory alloys (SMAs) is explored and discussed. This paper also envisages providing a comparative study of significant microstructural evolutions and features that are introduced by HSHPT processing. The plastic deformation mechanisms of the copper-based SMAs are investigated from macrostructural and microstructural points of view using optical and scanning electron microscopic techniques. In addition, significant grain size reduction brought about by the process is attested by X-ray diffraction and transmission electron microscopy. The transition temperatures have been determined by differential scanning calorimetry.
10.1007-s12666-021-02322-6	4	transformation; martensite; martensitic; phase; shape; beta; memory; shape memory; temperature; temperatures; martensitic transformation; gamma; transformation temperatures; effect; thermal	The microstructural properties and thermodynamic parameters before and after abrasion were examined for a bulk Cu86Al10Ta4 (%wt.) shape memory alloy produced by the arc-melting method. From the XRD and SEM-EDX microstructural analysis, it was found that the alloy provided alpha(Cu), gamma'(1)(Cu9Al4), gamma'(1) (2II), beta'(1)(18R), and Ta2Al3 phases before wear, while, after abrasion, depth grooves, wear debris, and ridges and delamination structures were observed. In the forward phase transformation, the DSC result displayed a single narrow peak, which represented beta(1) -> gamma'(1), which for the reverse martensitic phase transformation the peak was wide and displayed gamma'(1) -> beta(1). It was observed that the volume and mass losses, friction coefficient, wear coefficient, and wear rates are affected by changing the distance and applying load. The value of phase transformation temperatures, enthalpy, entropy, Gibbs free energy, and elastic energy of the bulk material changed after abrasion. Moreover, the post wear alloy exhibited shape memory behavior in both the heating and cooling processes.
10.1007-s12666-021-02495-0	-1		Cu-Zn-Al particles reinforced 6061Al composites were fabricated by friction stir processing (FSP). The microstructure and mechanical properties of the composites under the FSP and T6 heat treatment were investigated. Microstructure observation showed that Cu-Zn-Al particles were homogeneously distributed in the Al matrix. FSP resulted in grain refinement and the reduction of the number of beta-Mg2Si, and T6 heat treatment promoted the precipitation of fine particles (beta-Mg2Si). The introduced Cu-Zn-Al particles in the FSPed composites still exhibited reversible phase transformation between martensite and austenite. The tensile strength of the FSPed composites was inferior to that of base metal, while the elongation of composites was obviously enhanced. The tensile strengths of composites after T6 heat treatment increased greatly. The results indicated that FSP is an effective way to produce Cu-Zn-Al particles/Al composites with good mechanical properties.
10.1007-s12666-022-02747-7	6	grain; deformation; strain; strength; dislocation; cu-; tensile; size; ecap; grain size; sfe; ductility; hardening; high; stress	The C11000 billets were intensely deformed through equal channel angular extrusion (ECAE) up to eight passes. The deformed microstructure of the billet was assessed by electron-backscattered diffraction (EBSD). The mechanical properties of the extruded billets were evaluated by tensile and hardness tests. The microhardness and microstructural investigations at different positions of the billet thickness revealed development and homogeneity by increasing the number of passes. This result was approved by the uniform distribution of effective strain in the ECA-extruded samples at high passes which was obtained by DEFORM-3D software. It became clear that the average microhardness is significantly raised up to four passes of ECAE and thereafter it is slightly reduced when more passes are applied. Utilizing the sub-structural data, the yield strength of the billets was predicted. The model is consistent with the experimental results.
10.1007-s12666-023-02881-w	-1		To improve the engineering application of powder metallurgy Cu-12Al alloys in bearing workpieces, a machine learning (ML) procedure was proposed. The experimental feedback data were used to improve the ML extrapolation. Binary and ternary alloys data were used to build the ML model to predict quaternary alloys. A multi-objective express index was used to assess the comprehensiveness of the searched alloys. The experimental result of predicted alloy updates training data to search next alloy. Cu-13Al-5Fe-5Ni alloy was found to have higher tensile strength (381.6 MPa) and hardness (140.1 HB) than those of traditional Cu-12Al alloy. The microstructure indicated that the designed alloy has three precipitation phases to strengthen matrix. Further, the designed alloy has the balance between tensile strength and hardness. This work is of much practical significance in reducing trial-and-error tests to improve design efficiency for material design.
10.1007-s12666-023-02992-4	16	wear; composite; composites; powders; milling; particles; powder; wt; sliding; friction; hardness; matrix; mechanical; surface; properties	A comparative study on the variation in microstructure and wear behavior of tin bronze substrate surface alloyed with varying nickel content was carried out in this research . Cu-10Sn-XNi surface composite was developed using gas tungsten arc (GTA) heat source and friction stir processing (FSP) techniques. A stark comparison of the surface properties obtained by the two modification processes and the effect of Ni content were studied. The surface modification resulted in a reduction in the size of the grains, while the average grain size was comparatively lesser in GTA modified samples. Ni was found to be present in the alloyed zone as solid solution and also in the form of fine precipitates. A 30% increase in hardness was observed for both GTA and FSPed samples of which GTA exhibited superior increment. Same trend was also witnessed in the case of wear rate. The variation in hardness obtained at different levels of Ni concentration reiterated the formation of a functionally graded tin bronze alloyed with Nickel.
10.1007-s12666-023-03236-1	-1		The cooling rate has a huge effect on the microstructure and properties of shape memory alloys. In this work, taking Cu-13Al-5Fe high-temperature shape memory alloy as an example, the effects of cooling rate on the microstructure, shape memory effect and mechanical properties were studied. The results show that the alloy has good properties in the water-cooled condition. When the alloy under water-cooling state is deformed at room-temperature, the recovery strain is as high as 4.72%, and the phase transition temperature exceeds 357 celcius. Moreover, the ratio of temperature to recovery strain is higher significantly than that of other reported shape memory alloys. This class of Cu-13Al-5Fe alloy may be used as high-temperature shape memory materials with high and wide working temperature range as high-sensitive driver or detector.
10.1007-s12666-024-03291-2	-1		Copper-nickel (Cu-Ni) alloys are candidate materials for marine applications where bio-fouling and sea water corrosion resistance is crucial. Friction surfacing is a solid-state coating that reduces substrate dilution levels and intermetallic compound (IMC) formation between immiscible systems particularly useful to coat Cu on steel. In the present study, Cu-Ni alloy (90% Cu and 10% Ni) was attempted coat on the steel substrate at different combinations of the axial load, rotational speed and traverse speed. The coating nature and the dimensions were correlated with processing variables. Good bonding with substrate was identified at 7.85 kN axial load, 1000 rpm rotational speed and 1.0 mm/s traverse speed. The coatings were characterized with light microscopy, scanning electron microscope, X-ray diffraction, microhardness and potentiodynamic polarization testing. It was found that the friction surfaced coatings are free from defects; having very low base metal dilution, no IMCs formation poses similar corrosion resistance as that of consumable rod under the 3.5% NaCl environment.
10.1007-s12666-024-03297-w	17	wear; composites; coating; friction; composite; coatings; surface; tribological; properties; wear resistance; resistance; powder; sliding; matrix; wear rate	Cold spraying methods are used to prepare Cu/Ni composite coating on Q235 substrates. The porosity, micromorphology, and microhardness and corrosion properties of the copper coating prepared by cold spraying are studied. This experiment mainly explores the microstructure and corrosion resistance of Cu/Ni composite coatings prepared by different composition powder ratios. The heat treatment process of the coating was carried out to explore the effect of the heat treatment process on the microstructure and corrosion resistance of the coating. The results indicated that the porosity of the coating increases slightly with an increase in nickel powder content. The metal nickel plays an anodic protection role in the Cu/Ni battery. However, too much nickel will lead to too much anode material, and the overall structure of the coating will be destroyed after anode corrosion. The composite coating prepared with 40 wt% nickel powder has the best corrosion resistance. After heat treatment, the corrosion resistance of copper/nickel composite coatings is reduced, and the quality of the coatings is improved.Graphical AbstractCopper, nickel and their alloys have excellent corrosion resistance. The preparation of copper and nickel coatings on the surface of parts is a common anti-corrosion method. Metal copper also has excellent marine biological control performance. Copper and its alloys are widely used in the corrosion protection of parts in the marine environment. Cold spraying technology has the advantages of low spraying temperature, no oxidation phase change and low porosity. It also has the advantages of flexible processing and repairable damaged surface.
10.1007-s12666-025-03728-2	16	wear; composite; composites; powders; milling; particles; powder; wt; sliding; friction; hardness; matrix; mechanical; surface; properties	Two Cu-based powder alloys of composition Cu-2Zr and Cu-5Zr (at%) were synthesized by mechanical alloying of pure elemental Cu and Zr in appropriate amount for 30 h . X-ray line profile analysis of the alloyed powder of both compositions suggests the formation of Zr supersaturated Cu phase with a crystallite size below 20 nm. The powder alloys were consolidated into bulk form by two different routes of conventional cold compaction and sintering and spark plasma sintering at similar temperature of 800 degrees C. Microstructural characterization and density measurement show that the spark plasma sintering results in better densification than conventional cold compaction and sintering. Consequently, the consolidated Cu-5Zr alloy through spark plasma sintering exhibits best combination of electrical conductivity of 28% IACS and microhardness value of 302 VHN.
10.1007-s12666-025-03729-1	-1		This paper presents the results of a comprehensive study of samples of a serial Cu-Sn alloy after a single pass of asymmetric rolling (AR) with a true strain deformation of similar to 70%. During AR, an active transformation of the initial structure occurs at the macro- and microlevels, which leads to the formation of a grain-subgrain structure. At the macrolevel, a lamellar-type structure is formed in the rolling direction, and at the microlevel, a complex lamellar and cellular structure of the nanometre range with a minimum size of similar to 50 nm is formed in macrobands. The yield strength increases from 200 to 805 MPa, and wear resistance under dry friction conditions increases noticeably. The achieved properties in terms of yield strength after AR are twice as high as those of competing industrial methods of strengthening the Cu-Sn alloy.
10.1007-s13204-018-0672-5	-1		The ultrafine powder of the Heusler Cu-13,1Mn-12,6Al (wt%) alloy produced by electrical spark dispersion (ESD) in ethanol and the pellets prepared by pressing of the powders and aged in various gas environment (air, Ar, vacuum) were studied by XRD, nuclear magnetic resonance, magnetic and electric transport methods. The constituent phases were identified as b.c.c. alpha-Cu-Mn-Al, f.c.c. gamma-Cu-Mn-Al, -Cu2MnAl, and oxides. The sizes of the coherently scattering domains (CSD) and the saturation magnetizations were in the range of 4-90 nm and 0-1.5 Am-2/kg, respectively. Al-27 and Cu-63 NMR spectra of the powders and pellets have shown hyperfine structure caused by contributions from atomic nuclei of the constituent phases. The aging of pellets in different gas environments had effect on their phase composition but no effect on dispersion of the phases. In contrast to the as-cast alloy, electrical resistance of the pellets evidenced semiconducting behavior at elevated temperatures due to the presence of metal oxides formed on the surfaces of nanoparticles.
10.1007-s13204-020-01442-7	4	transformation; martensite; martensitic; phase; shape; beta; memory; shape memory; temperature; temperatures; martensitic transformation; gamma; transformation temperatures; effect; thermal	The work studies the deformational effects in aged Cu-Al-Mn alloys. The martensitic transformation temperatures were determined by measuring the low-field magnetic susceptibility and electrical resistance as a function of the exposure time during isothermal ageing. The values of linear coefficients of thermal expansion of high and low-temperature phases were measured and the volume effect of martensitic transformation was estimated. Based on the uniaxial tension data, the phase diagram of austenite and martensite stability was constructed. The critical stress for the strain-induced martensite formation has been estimated and the factors influencing the degree of superelastic recovery have been elucidated. The influence of size effects on superelastic deformation behavior and the intervals of their occurrence in aged polycrystalline samples were noted.
10.1007-s13204-020-01494-9	4	transformation; martensite; martensitic; phase; shape; beta; memory; shape memory; temperature; temperatures; martensitic transformation; gamma; transformation temperatures; effect; thermal	A comparative analysis of the magnetic, size and deformation effects of martensitic transformation in aged Cu-Al-Mn alloys with a minimum width of the temperature hysteresis was performed. According to the experimental studies of the behavior of alloys during martensitic transformations, the changes in temperature dependences of thermal expansion, magnetic susceptibility and electrical resistance, depending on preliminary thermomagnetic treatment of alloys, were found. The thermomagnetic treatment contributes to a change in the magnitude of volume effect of martensitic transformation. Using magnetic analysis, the state and distribution of precipitated particles, affecting both the magnetic characteristics and the volume effects of martensitic transformation in the alloys, were determined.
10.1007-s13369-015-1788-5	2	corrosion; surface; film; electrochemical; films; spectroscopy; layer; current; solution; potential; resistance; composition; x-ray; ions; showed	In this work, the electrochemical behavior and passivation of Cu-30Zn alloy in aqueous NaOH solutions was investigated using various electrochemical methods. Potentiodynamic polarization curves showed that increasing NaOH concentration leads to increase corrosion current densities. Mott-Schottky analysis indicated that the passive films displayed p-type semiconductive characteristics and the acceptor densities increased by increasing NaOH concentration, while the flat band potential decreased. Moreover, electrochemical impedance spectroscopy studies showed that the impedance value decreased by increasing NaOH concentration, due to increase in the Zn dissolution of Cu-30Zn alloy, which is consistent with the results of the polarization experiment and X-ray diffraction patterns.
10.1007-s13369-017-2661-5	-1		Coatings are extensively used as corrosion resistance, wear resistance, and antibacterial surfaces. Copper and copper alloys are among the most widely applied coating materials for industrial and medical applications. In this work, mechanical assessment of Cu, Cu 4% Sn, Cu 17% Ni 10% Zn (German Silver), and Cu 17% Al 1% Fe coatings deposited on stainless steel 316L substrates using twin wire arc thermal spraying is studied experimentally. Microstructure, hardness, and scratch resistance were studied for all coated samples. The effects of having different coating compositions on the mechanical properties are analyzed. The effect of the coatings thickness is also investigated for Cu 17% Ni 10% Zn and Cu 17% Al 1% Fe coatings with different thicknesses between 200 and 400 ae mu m. The study focused on how the scratch resistance increases with increasing the coating thickness on the expense of the adhesion. A comparison of the coating hardness profile between different copper and copper alloy compositions was presented. An interesting observation was that even though scratch hardness increases with the coating thickness, hardness decreases as a function of the distance from the interface.
10.1007-s13369-018-3222-2	-1		Thermally sprayed copper and copper alloy coatings are among the most widely used coating materials for several industrial and medical applications to serve various functions such as corrosion resistance, wear resistance and antibacterial coating applications. In the present study, wear behavior of twin arc spray Cu, Cu 4%Sn (tin bronze), Cu 17%Ni 10%Zn (German silver) and Cu 17%Al 1%Fe (aluminum bronze) coatings is investigated experimentally. Wear tests were conducted using ball-on-disk configuration against a 440C stainless steel ball as a counterface. The effect of normal load on the coefficient of friction and wear behavior was investigated. SEM and 3D optical profilometry were used to characterize the coatings in terms of morphology and surface roughness. It is observed that copper coatings with aluminum and tin bronzes have high wear resistance and low coefficient of friction among the tested coatings, mainly due to their high hardness and coherent splats. It was also found that wear rate increases with the normal load.
10.1007-s13369-021-05660-1	-1		Copper and its alloys are widely used in different industrial fields, but environmental impact could lead to corrosion and therefore may result in poor performance of these materials. To ensure safe operation of the equipment, it is necessary to study the corrosion behavior. Here, we introduce a novel study of the kinetics of complete isothermal oxidation in air of pure Cu and Cu1-xGax (0 < x < 0.15) solid solution powders by the periodic weighment method and XRD phase analysis. It is shown that experimental oxidation curves for each Ga-containing sample studied are perfectly described by single-term exponential function. Analysis of these curves made it possible to calculate the main oxidation parameters of Cu1-xGax powders. As a result, it was shown that the activation energy of oxidation increases from 98 to 114 kJ/mol with Ga content increasing from 0 to 12 at%, while the oxidation rates decrease by almost 100 times. Oxidation of Cu1-xGax powders is accompanied by the depletion of initial solid solution with Ga atoms followed by the formation of Ga2O3, CuO and CuGa2O4 phases. Thus, Ga dopants significantly increase the corrosion resistance of copper at annealing in air (600-850 degrees C). The results obtained contribute to the optimization of Cu1-xGax solid solution content for development of the targets for deposition of multilayer coatings for technical or medical purposes, for example, CuIn1-xGaxSe2 for solar cells or thin copper-gallium-doped silica-rich bio-active glass implant-type coatings.
10.1007-s13369-022-07592-w	2	corrosion; surface; film; electrochemical; films; spectroscopy; layer; current; solution; potential; resistance; composition; x-ray; ions; showed	The cyclic voltammetry and chronoamperometry methods are used in the present work for the purpose of investigating the electrodeposition mechanism of Cu-Sn alloys onto Pt and Mo substrates from a slightly acidic aqueous electrolyte (pH asymptotic to 4.2) containing CuCl2 and SnCl2 as metal sources, and tri-sodium citrate as a complexing agent. The structural properties of the deposits were characterized by means of the X-ray diffraction (XRD) technique, whereas the surface morphology and composition were examined using the field-emission scanning electron microscopy (FESEM) and energy-dispersive spectroscopy (EDS). The resulting crystalline films were mainly composed of Cu, Sn, and intermetallic Cu6Sn5 phases with spherical grains, at the early stages of nucleation, and a mixture of spherical grains and dendrites with hierarchical secondary branches after long electrolysis duration. The analysis of potentiostatic current transients, using the Scharifker-Hills model, showed that the electroplating of Cu-Sn alloy followed the instantaneous nucleation mode on platinum substrate and the progressive nucleation mode on the molybdenum substrate.
10.1007-s13369-023-07940-4	2	corrosion; surface; film; electrochemical; films; spectroscopy; layer; current; solution; potential; resistance; composition; x-ray; ions; showed	Olive leaf extract (OLE) was investigated to inhibit the copper corrosion in alkaline (0.5 M KOH solution), owing to the fact that it is eco-friendly, nontoxic, and paltry substance. The inhibitory action of olive leaf extract was investigated utilizing open circuit potential, cyclic voltammetry, potentiodynamic polarization, electrochemical impedance spectroscopy (EIS), scanning electron microscopy (SEM), energy-dispersive X-ray analysis (EDX), atomic force microscopy (AFM), and X-ray photoelectron spectroscopy (XPS) techniques. The results revealed that olive leaf extract, inhibited the corrosion of Cu in the investigated alkaline environment, yielding maximum inhibition efficiencies of 90.68%. The inhibitory efficiency value rises with rising the amount of olive leaf extract and reduces by rising temperature. The inhibitory action was attributed to olive leaf extract adsorbed on copper surface, which created a charge and mass movement barrier, shielding the metal from hostile ions. OLE works fundamentally as a cathodic inhibitor, according to polarization curve parameters. EIS measurements have shown that a more resistive passive film is formed on the Cu in the presence of OLE. The EIS data were fitted to theoretical data according to a proposed model representing the electrode/electrolyte interface, and the equivalent circuit parameters were calculated. The extracted molecules adsorb on the surface of metal according to Langmuir adsorption isotherm. According to SEM/ EDX, AFM, and XPS investigations, the inhibitor can compose a preservative layer on the surface. Density functional theory was furthermore utilized for examining the common components of olive leaf extract. The mechanism of adsorption OLE on the surface of copper was studied utilizing Monte Carlo simulation. The theoretical outputs were discovered to support the practical outcomes.
10.1007-s40192-022-00275-2	-1		The evolution of texture during different mechanical processes is an integral part of Integrated Computational Materials Engineering (ICME) of metals and alloys. In the present work, PRISMS-Plasticity TM, an open-source rapid texture evolution analysis pipeline, based on the Taylor model is integrated into the open-source crystal plasticity software, PRISMS-Plasticity. However, unlike PRISMS-Plasticity, the pipeline does not involve any finite element solver. The Taylor-type crystal plasticity model is used to capture the evolution of texture. The pipeline aims to significantly minimize the cost of texture evolution simulations, so one can use the framework along with data-driven ICME design methods and generate high-throughput data with low costs for general analysis or machine learning applications. All the rate-independent and rate-dependent crystal plasticity models available in the Materials library of PRISMS-Plasticity can be used in the pipeline. The models can capture extension twinning as an important deformation mechanism in alloys with hexagonal close-packed crystal structures. The PRISMS-Plasticity TM pipeline is efficiently integrated with experimental characterization techniques such as electron backscatter diffraction (EBSD), and these pipelines use other open-source software packages such as DREAM.3D where appropriate. In addition, the PRISMS-Plasticity TM results are integrated with the PRISMS Center Materials Commons information repository. In this investigation, three different examples of texture evolution in a polycrystalline OFHC copper, extruded Mg alloy ZK60A, and an aluminum alloy 7075-T6 are presented to show the capability of PRISMS-Plasticity TM. The pipeline can take advantage of the parallel performance of PRISMS-Plasticity and scales exceptionally well for large problems running on multiple processors. The computational efficiency of this tool can be used to build large databases for use in machine learning applications. Such a large dataset is established containing process-microstructure relationships of 7075-T6 Al. The extracted data is visualized in 2-D latent space using an unsupervised machine learning model called the variational autoencoder (VAE). The trained VAE model is used to identify economical process sequences which lead to desired properties.
10.1007-s40192-025-00409-2	-1		Copper-nickel alloys are commonly used for marine applications such as piping, cladding, and other seawater facing components. These Cu-Ni components are conventionally manufactured using both cast and wrought processes. However, limited information is available regarding the high-temperature properties of Cu-Ni. The following data descriptor report documents the thermo-physical and thermo-mechanical properties of material taken from a 70/30 Cu-Ni casting as well as thermo-mechanical properties of a 70/30 Cu-Ni weld filler material. These results will help empower Integrated Computational Materials Engineering (ICME) efforts through the integration of the data within software packages. The raw data, in machine-readable form, are available at the University of Michigan's Materials Commons data repository here: https://materialscommons.org/ Norkett and Fisher (Temperature-Dependent Material Property Database for 70/30 Cu-Ni Castings 2025).
10.1007-s40195-016-0478-y	-1		The microstructure and nano-hardness of the pure copper and oxide dispersion-strengthened (ODS) copper alloy subjected to 1.4 MeV Au ions irradiation at room temperature were investigated. After irradiation, dislocation-loops form in both materials, while voids can only be generated in the pure copper. Compared with the irradiated pure copper, larger average diameter and lower number density of irradiation-induced dislocation-loops were detected in the ODS copper alloy, revealing that high-density dislocation and large volume of Al2O3 particles existing in the ODS copper alloy can act as effective sinks for the irradiation-induced defects. It was also detected that irradiation hardening in the ODS copper alloy is lower than that in the pure copper. The microstructure and nano-hardness results reveal that the ODS copper alloy has a better irradiation tolerance than the pure copper. In addition, the average diameter of the Al2O3 particles in the ODS copper alloy decreases after irradiation, because the Al-O chemical bonds are decomposed and the atoms are redistributed in the matrix during the irradiation process. This work reveals that the irradiation tolerance of the copper can be effectively enhanced by adding nano-sized Al2O3 particles into the matrix.
10.1007-s40195-016-0505-z	-1		Porous copper was prepared successfully by physical vacuum dealloying method using the CuZn alloy precursors (Cu30Zn70, Cu40Zn60 and Cu50Zn50 alloys). The micron porous copper showed a three-dimensional continuous porous structure with 1-5 mu m pore size. With the increase of the Zn content in the CuZn alloy, the pore structure of the porous copper was more uniform and ordered. Temperature was the key factor for physical dealloying, and the optimized temperature was 500 degrees C for the CuZn alloy. The pores would fuse and disappear when the temperature was over 500 degrees C. Physical vacuum dealloying was an effective preparation method for porous copper, which can be used to prepare other porous metals based on the sublimation and the Kirkendall effect.
10.1007-s40195-018-0711-y	-1		Copper matrix composites were prepared through spark plasma sintering (SPS) process, mixing fixed amount of reduced graphene oxide (rGO) with the different amounts of Cr. In the sintered bulk composites, the layered rGO network and uniform Cr particles distributed in the Cu matrix. Both of mechanical blending and freeze-drying stages of the wet-mixing process obtained the Cu/Cr/rGO mixture powders, and then SPS solid-phase sintering realized the faster densification of these mixture powders. The hardness and compressive yield strength of the Cu-Cr-rGO composites depicted the higher values than those of pure Cu and single rGO-added composite, and they were gradually increased with increasing Cr. The rGO/Cr hybrid second-phases are believed to be beneficial to strengthening Cu matrix. The relevant formation and strengthening mechanisms involved in Cu-Cr-rGO composites were discussed.
10.1007-s40195-018-0719-3	6	grain; deformation; strain; strength; dislocation; cu-; tensile; size; ecap; grain size; sfe; ductility; hardening; high; stress	Ultra-strong joints of pure Cu and Cu-30Zn alloy were obtained by friction stir welding under flowing water. The effects of heat inputting condition and material characteristics on the morphologies, microstructures and mechanical properties of welding joints were studied. Defect-free stirring zones of pure Cu and Cu-30Zn were characterized by onion-ringed structure and plastic flowing bands, respectively. Both low stacking fault energy and fast cooling condition contributed to the formation of small recrystallized grains less than 1 mu m in stirring zones. The welding joints in both materials exhibited enhanced mechanical performances due to ultrafine-grained microstructure in stirring zones and disappearance of soft heat-affected-zone. The technique of digital image correlation was used to study the tensile deformation behaviors of welding joints and verify the improved tensile properties.
10.1007-s40195-018-0766-9	-1		In the present work, a CuCrZr alloy characterized by ultrafine grains and nanoscale particles was prepared by equal-channel angular pressing (ECAP) at 450 degrees C. A desired combination of a tensile strength (580 MPa) and an electrical conductivity (81% International Annealed Copper Standard) is simultaneously obtained in the as-ECAP-processed CuCrZr alloy without additional aging treatment. The improved properties can be mainly attributed to the ultrafine grains and nanoscale precipitates. This processing may pave a way to develop the CuCrZr alloys having high strength and high electrical conductivity for engineering applications.
10.1007-s40195-018-0781-x	-1		The effect of cryorolling on the precipitation process of deformed Cu-Ni-Si alloys was investigated through in situ synchrotron X-ray diffraction technique. The results demonstrate that the precipitation process is significantly accelerated by cryorolling. Cryorolling produces higher dislocation density, which provides more heterogeneous nucleation sites for Ni2Si precipitates, hence promotes precipitation. In the early stage of aging, the enhanced nucleation of precipitates accelerates the depletion of supersaturation, and finer precipitates are obtained. In addition, recrystallization is promoted as a result of high stored energy in the cryorolled Cu-Ni-Si alloys, which facilitates the formation of discontinuous precipitation in the late stage of aging.
10.1007-s40195-019-00953-9	-1		Microalloying is an effective method to improve the comprehensive properties of copper alloys. The effects of magnesium on the microstructure, mechanical properties and anti-stress relaxation properties of CuNiSi alloys have been investigated. Results demonstrated that magnesium plays significant roles in refining the dendritic microstructure of the as-cast ingot, accelerating the precipitation decomposition, improving the mechanical properties and increasing the anti-stress relaxation properties. The incremental strength increase is due to the Orowan strengthening from the nanoscale Ni2Si and Ni3Al precipitates. As compared with the Cu-6.0Ni-1.0Si-0.5Al (wt%) alloy, the ultimate tensile strength of the designed Cu-6.0Ni-1.0Si-0.5Al-0.15Mg (wt%) alloy increases from 983.9 to 1095.7 MPa, and the electrical conductivity decreases from 27.1 to 26.6% IACS, respectively. The stress relaxation rates of the designed Cu-6.0Ni-1.0Si-0.5Al-0.15Mg alloy are 4.05% at 25 degrees C, 6.62% at 100 degrees C and 9.74% at 200 degrees C after having been loaded for 100 h, respectively. Magnesium significantly promotes nucleation during precipitation and maintains small precipitate size.
10.1007-s40195-022-01433-3	-1		Ultrasonic cavitation radiates huge power in a small solidifying bulk, leading to significant grain refinement, purification and homogenization of the final alloys. Ultrasound vibration has mostly been used for treating the solidification of light metals, but it is difficult to directly introduce ultrasonic vibration into copper alloy due to the lack of proper sonotrode. In this work, we have used a Sialon ceramic sonotrode to propagate acoustic waves in a Cu-Cr alloy melt. Significant grain refinement and modification of primary Cr have been obtained. With the ultrasound vibration treatment, the mechanical properties of the as-cast Cu-Cr alloy have been improved. The wear resistance of the Cu-Cr alloy has also shown enhancement with respect to the untreated alloy.
10.1007-s40195-025-01901-6	14	strength; properties; conductivity; electrical; mechanical; cu-; grain; mpa; electrical conductivity; aging; precipitation; phase; mechanical properties; tensile; phases	The rapid expansion of marine industries has created an urgent demand for advanced engineering materials with superior multifunctional performance. While Cu-Ni alloys demonstrate favorable stability and tribological characteristics, their practical applications are constrained by compromised thermal conductivity and insufficient mechanical strength due to the solid solution of a high amount of Ni in the Cu matrix. Cu-Ni matrix composites reinforced with hexagonal boron nitride (h-BN) have garnered significant attention due to their potential for tailored mechanical and thermal properties. However, challenges such as BN agglomerations in Cu-Ni matrix and poor interfacial bonding hinder their practical applications. To address these limitations, this study proposes an innovative fabrication strategy for boron nitride nanosheets (BNNSs) reinforced Cu-Ni composites by integrating the in situ synthesis of BNNSs on Cu powders via chemical vapor deposition with powder metallurgy. Benefited by the in situ strategy, BNNSs with high crystallinity distribute uniformly within the Cu matrix and have an intimate interfacial bonding without voids or other types of defects. Remarkably, the BNNSs/Cu-30%Ni composite achieves simultaneous enhancement in strength and ductility, exhibiting an ultimate tensile strength of 417 MPa and fracture elongation of 17.5%, representing 30% and 118% improvements over pure Cu-Ni alloys, respectively. This exceptional mechanical synergy originates from threefold strengthening mechanisms: grain refinement, mobile dislocation pinning, and efficient stress transfer via robust interfaces. The microstructural analysis confirms that homogenous distribution of BNNSs optimized stress distribution, mitigating strain localization in the composites. Fractographic examination demonstrates uniformly distributed dimples containing embedded BNNSs, indicative of effective crack bridging and deflection during failure. Furthermore, the composite possesses excellent corrosion resistance comparable to matrix alloys, while achieving 21.23% enhancement in thermal conductivity and 20% reduction in coefficient of friction. The scalable fabrication protocol successfully resolves longstanding challenges in BNNSs dispersion and interfacial bonding, offering a viable pathway for designing high-performance CMCs for marine applications.
10.1007-s40430-019-2080-5	-1		In surface engineering, new coatings and deposition techniques for decreasing wear have been proposed. However, the tribological behaviors of these coatings under lubricated sliding with biodegradable oils are unknown. The objective of this study was to evaluate the tribological behaviors of two hydraulic biodegradable oils, namely hydraulic environmental ester oil synthetic (HEES) and hydraulic oil environmental polyalphaolefin (HEPR), with hydraulic mineral oil (HLP), using a pin-on-disk tribometer. In the sliding tests, a Cu-35Zn sphere against a flat surface is coated with WC-10Co4Cr alloy using a HVOF thermal spray. The Stribeck curve was used to evaluate the performances of the lubricants. The coefficient of friction, the contact pressure, and the film thickness were determined. In addition, the coefficient of wear of the sphere was evaluated, and the oil with the lowest value was identified, which was HEPR in this case. In long-term tests, HEPR was affected by the stick-slip phenomenon, which increased the coefficients of friction and wear. Furthermore, the mechanism of adhesion of the sphere on the disk was more evident with the use of HEES compared to HLP. The highest concentrations of Zn and P and the pressure-viscosity coefficient value, which was detected in the mineral oil, caused friction reduction and lower damage to the surfaces. Therefore, it is important to evaluate the tribological conditions of synthetic bio-lubricants for applications in hydraulic systems.
10.1007-s40430-023-04641-9	-1		In this study, numerical simulations were conducted using finite element analysis with a Twist Equal-Channel Angular Pressing (T-ECAP) die, employing commercially pure Cu and Cu-0.7Cr-0.07Zr alloy. Six different combinations of twist angle (omega) and twist slope angle (beta) were tested in a new die. The punch force ranged from 100 to 120 kN for the considered geometries, except for the omega = 90 degrees and beta = 45 degrees configuration, where the maximum load reached 170-210 kN. Similar to effective strains, the center of the cross section exhibited lower effective stresses than the surfaces. In optimizing the T-ECAP die, the configuration that yielded reduced heterogeneity in the distribution of stresses and strains, coupled with a lower pressing load, was the die with phi = 120 degrees, phi = 22 degrees, omega = 90 degrees, and beta = 25 degrees. This configuration imposed an average effective strain of 3.5 per pass.
10.1007-s40544-017-0157-7	16	wear; composite; composites; powders; milling; particles; powder; wt; sliding; friction; hardness; matrix; mechanical; surface; properties	The present study synthesized Cu-4 wt% Ni matrix composites reinforced with different percentages of TiC (0, 2, 4, 6, and 8 wt%) through high-energy ball milling, followed by compaction and sintering. The friction and wear behavior was examined at four different normal loads of 5, 10, 15, and 20 N. A constant sliding speed of 1.25 m/s was maintained while sliding against a hardened counterface made of EN31 steel (HRC 60) under ambient conditions using a pin-on-disk test rig. The composite hardness increased until the addition of 4 wt% of TiC, beyond which it was observed to decrease. Such a trend may be attributed to the TiC agglomeration in the composites containing relatively larger amounts of TiC (i.e., 6 and 8 wt%). The wear rate linearly increased with the load. However, the composites exhibited a lower rate of wear than the matrix alloy, which may have resulted from the relatively higher hardness of composites. The observed friction and wear behavior has been explained on the basis of hardness and presence of the transfer layer on the worn surface and its nature, i.e., loose or well compacted. Addition of 4 wt% TiC showed the optimum performance in terms of friction and wear caused by its higher hardness and ability to hold a transfer layer of a relatively larger thickness compared to the other materials. The wear mechanism for the Cu4Ni matrix alloy was a mix of adhesive and oxidative wear and primarily abrasive for the composites containing hard TiC particles.
10.1007-s40544-020-0440-x	-1		A unique low-to-high friction transition is observed during unlubricated sliding in metals with a gradient nano-grained (GNG) surface layer. After persisting in the low-friction state (0.2-0.4) for tens of thousands of cycles, the coefficients of friction in the GNG copper (Cu) and copper-silver (Cu-5Ag) alloy start to increase, eventually reaching a high level (0.6-0.8). By monitoring the worn surface morphology evolution, wear-induced damage accumulation, and worn subsurface structure evolution during sliding, we found that the low-to-high friction transition is strongly correlated with distinct microstructural instabilities induced by vertical plastic deformation and wear-off of the stable nanograins in the subsurface layer. A very low wear loss of the GNG samples was achieved compared with the coarse-grained sample, especially during the low friction stage. Our results suggest that it is possible to postpone the initiation of low-to-high friction transitions and enhance the wear resistance in GNG metals by increasing the GNG structural stability against grain coarsening under high loading.
10.1007-s40843-025-3423-6	14	strength; properties; conductivity; electrical; mechanical; cu-; grain; mpa; electrical conductivity; aging; precipitation; phase; mechanical properties; tensile; phases	Due to its low cost, eco-friendliness, and excellent thermoelectric (TE) performance, copper sulfide (Cu2-xS) has emerged as a promising TE material. Nevertheless, the trade-off between enhanced electrical conductivity and suppressed thermal conductivity is a critical challenge. This study systematically investigated an intermediate doping approach through the strategic incorporation of copper alloys (bronze, cupronickel, and brass) to optimize the TE performance of Cu1.8S. The proposed strategy realized partial copper source replacement and solved the problem of excessive Cu vacancy in Cu1.8S. Comprehensive characterization demonstrated that compared to conventional direct elemental doping, the intermediate doping with Zn, Sn, Pb, and Ni elements achieved superior TE performance. Additionally, this improvement was from dual synergistic mechanisms: the increased solubility limits facilitating optimized carrier concentration, and the in situ formation of the nanoscale second phase effectively scattered phonons. Ultimately, the Cu1.8S + 5 wt% bronze + 3 wt% cupronickel + 2 wt% brass sample reached a remarkable ZT value of 1.7 at 673 K, which was a 247% enhancement over pristine Cu1.8S and surpassed all previously reported ZT values for the Cu1.8S system. This study established a novel paradigm of intermediate doping in optimizing the TE properties, providing a new perspective for other alloy-based TE systems.
10.1007-s40962-022-00812-x	16	wear; composite; composites; powders; milling; particles; powder; wt; sliding; friction; hardness; matrix; mechanical; surface; properties	In this study, various amounts of nano-zirconia (ZrO2) were added as a reinforcement particle to synthesize Cu-10Sn-xZrO(2) alloy using stir casting techniques. The mechanical and wear properties of metal matrix composites depend on the type of reinforcement material, morphological features and amount of the reinforcement material is added to matrix. The developed alloy obtained hardness ranging from 69 to 87 BHN for the addition of 0 to 12 wt% of nano-ZrO2 reinforcement particles. The ultimate tensile strength of developed alloys increased ranging from 271 MPa to 345 MPa, while yield strength showed 220 MPa to 263 MPa. Results indicate that ultimate tensile strength and yield strength of the reinforced alloys showed better mechanical properties than base alloy, which shows the significant influence of addition of reinforcement particles. The wear behavior of the developed alloys were examined using pin-on-disk tribometer. The developed reinforced alloys show that there was an increase in wear resistance with increasing the amount of nano-ZrO2 particles. However, results indicate that increase in wear rate with increase in applied load and sliding speed, with the increase in reinforcement particles showed better wear resistance at higher applied load and sliding speed as compared to base alloy. Microstructural features of the worn surface carried out using scanning electron microscopy (SEM). Worn surface analysis exhibits that wear resistance increases at 8 and 12 wt% of nano-ZrO2 particles. The prepared reinforced alloys exhibit excellent wear resistance, and hence, the developed reinforced alloys can be potentially used for various applications such as bearings and bushes.
10.1007-s40962-022-00877-8	-1		With the increasing use of metal semi-solid forming technology in the production of high-quality copper alloy parts, foundational research on the robust preparation of copper alloy semi-solid slurry as key components and foundation of copper alloy semi-solid parts is critical. Therefore, based on the explosive nucleation theory and the 3D-CAFE method, the effects of the length of the melt-constrained flow-induced nucleation channel (185, 250, 315, and 365 mm), which is the core component of self-designed and developed fully enclosed melt-constrained flow-induced nucleation metal semi-solid slurry preparation device, on the temperature field distribution and microstructure of CuSn10P1 alloy during the of semi-solid slurry preparation was studied. The research results show that the numerical simulation results agreed with the experimental results. As the melt-constrained flow-induced nucleation channel length was increased from 185 to 365 mm, the chilling effect of the channel on the CuSn10P1 melt initially increased and then decreased. When the length of the melt-constrained flow-induced channel reached 315 mm, the most uniform temperature distribution, most homogeneous microstructure, and finest microstructure were obtained. Moreover, the grains had an average equivalent diameter of only 30.43 mu m and with the distribution of 633/mm(2).
10.1007-s40962-023-01166-8	14	strength; properties; conductivity; electrical; mechanical; cu-; grain; mpa; electrical conductivity; aging; precipitation; phase; mechanical properties; tensile; phases	The evaluation of mold properties is crucial in the foundry industry to ensure efficient and high-quality casting production. This study focuses on the assessment of mold properties using silica sand, copper slag, and their mixture as molding materials in the sodium silicate, CO2 (carbon dioxide) chemical binder process. The properties investigated include mold hardness, permeability, and compressive strength . The aim is to evaluate their suitability and performance in comparison with traditional molding materials. The results indicate that a mixture of 6% sodium silicate and 15 sec of CO2 gas passing is highly effective in achieving optimum mold properties for both slag and sand molds. These properties remained stable even after prolonged exposure to different weathering conditions, highlighting the durability of the molds. Furthermore, the study revealed that the combination of sand and slag yields mold properties that lie between those of the pure ingredients. Specifically, a mixture comprising 80% sand and 20% slag exhibited the most desirable properties. Additionally, investigations were conducted using a 20% sand and 80% slag mixture, which demonstrated improvements in mold properties. In terms of material substitution, the evaluation of mold properties using the CO2 process showed that copper slag displayed similar characteristics to sand. This finding suggests that copper slag can serve as a suitable alternative to partially or fully replace silica sand in mold-making applications.
10.1007-s40962-025-01646-z	-1		Using virtual prototyping and numerical simulation, this study presents the optimization of the feeding system employed in an unconventional investment casting process, which applies centrifugal force perpendicular to the rotation axis to inject molten metal into refractory plaster molds. The objective is to enhance the manufacturing of a miniaturized S-shaped auxetic structure. Auxetic structures, known for their negative Poisson's ratio, are widely used across various industries, and their complex geometry requires a high-precision casting process. The metal alloy used is an aluminum bronze with shape memory functionality (Cu-Al-Mn SMA). Numerical simulation was performed using a commercial simulation software, ProCAST (R), and experimental parameters as input data. In this analysis, ten design of casting models were proposed, with the fifth model proving ideal, eliminating shrinkage defects, filling failures, and unwanted circulation, while also reducing injection time.
10.1007-s40962-025-01682-9	-1		In casting, mold design is critical as it directly influences defects such as porosity, which can reduce production efficiency and quality. Aspects of rigging design related to metal flow components-including risers, feeders, runners, and in-gates-significantly impact defect formation by controlling the molten metal's flow within the mold. However, in the existing literature, the interactions between these design elements are often examined separately, and comprehensive studies that are both systematic and experimentally validated remain scarce. In this study, defects in water faucets produced from Cu-Zn alloy using the low-pressure die casting method (LPDC) were investigated. The aim of this study is to understand the effects of mold design parameters (specifically the feeder, riser, and gating systems) on porosity formation. In this context, five different mold designs were developed and analyzed through simulation. Based on the results, the optimized design was tested under mass production conditions. The simulation outputs, 2D radiographic images, and microstructural examinations were compared, and the findings were validated through experimental data. The results demonstrated that feeder optimization, in particular, plays a critical role in porosity control. The strong correlation between the simulation data and the radiographic and microstructural analyses reinforced the methodological robustness of the study. Furthermore, the successful leakage test results of the parts manufactured using the optimized design confirm that the proposed approach is both feasible and reliable for production applications.
10.1007-s40962-025-01740-2	-1		Solutionizing is a critical heat treatment process in which a metal alloy is heated to a temperature, just below the solvus point, but not necessarily below the melting point and sustained at that temperature for a set period of time so that one or more constituents enter into a solid solution followed by rapid quenching for maintaining the homogeneous structure. Studies focusing on the influence of heat treatment, specifically solutionizing, to improve the performance of cast Cu-Sn alloys have been very few. This study investigates the effect of solutionizing temperature and time on the morphological characteristics and hardness value of cast Cu-6Sn alloy. The alloy samples were subjected to solutionizing temperatures of 780 degrees C, 820 degrees C, 860 degrees C at holding times of 3 h, 6 h, 9 h and 12 h . The hardness of Cu-Sn alloy under different solutionizing conditions showed an increase of 22-40% when compared with as-cast Cu-Sn alloy. Optimum solutionizing time for the cast Cu-Sn alloy was identified as 6 h and the optimal solutionizing temperature was determined to be 780 degrees C.
10.1007-s40999-018-0321-0	-1		Cu-Al-Mn is a type of shape memory alloy that has been evaluated for seismic applications in recent years. However, the rate-independent behavior of this new material has been proved in seismic applications in previous studies, but dependency on the temperature has been rarely studied. In this paper, seismic response dependency in a steel braced frame was evaluated under five different temperatures: -40, -25, 0, 25 and 50 degrees C. For this purpose, a one-bay one-story Cu-Al-Mn X braced frame was selected. At first, the response of frame was provided under a record scaled with various PGA and then five scaled records were selected for more evaluation. From the results, the axial force and top acceleration of frame increased with enhancing temperature. The difference of top acceleration in the lowest and highest temperature was 30%. In contrast, there was a drop in the maximum drift and maximum strain of brace with increasing temperature. The percentage changes of maximum drift and maximum strain were in the average values of 44 and 47%, respectively. Changes in all cases were almost linear. Results of the frame under seven different scaled records almost showed similar tendency. However, change in environmental temperature affected time history drift angle, especially at a temperature less than 0 degrees C, but in most earthquakes, maximum drift angle and strain increased with decreasing temperature and there was decline in top acceleration. The percentage of changes varied from 32 to 72% for drift angle and 20-42% for top acceleration.
10.1007-s41230-020-9140-4	-1		The Cu-Ti-Si alloys containing in-situ formed Ti(5)Si(3)are prepared. In order to clarify the Ti(5)Si(3)formation processes and its microstructure characteristics, the as-cast and deeply etched Cu-Ti-Si alloys with different compositions and cooling rates were investigated using scanning electron microscopy (SEM), transmission electron microscopy (TEM) and X-ray diffraction (XRD). It is found that the eutectic Ti(5)Si(3)phases in Cu-Ti-Si alloys are rod-like with hexagonal cross section which tend to intertwine with each other to form a firm skeleton like a bird nest structure which can make the alloys keep their original shape even after etching off the Cu matrix. In addition, there is Cu in the center of many Ti(5)Si(3)rods, resulting in a core-shell structure. With the increase of the cooling rate, Ti(5)Si(3)distributes more uniformly, and the diameter of Ti(5)Si(3)significantly decreases, with a minimum size of less than 100 nm, while the aspect ratio of Ti(5)Si(3)increases.
10.1007-s41230-025-4045-x	15	aging; strength; conductivity; electrical conductivity; electrical; mpa; treatment; strengthening; degrees; cu-; cold; precipitation; tensile strength; tensile; iacs	The Cu-12Fe alloy has attracted significant attention due to its excellent electrical conductivity and electromagnetic shielding capability, high strength, cost-effectiveness, and recyclability. In the present work, the Cu-12Fe alloy strip with the thickness of 2.4 mm was successfully produced by twin-roll strip casting. The microstructure and properties of the Cu-12Fe alloy was tailored by cold rolling and aging treatment. The tensile strength of the as-cast strip is approximately 328 MPa and its elongation is 25%. The Fe phase randomly dispersed in the matrix, and the average size of Fe-rich phase is 2 mu m. Besides, enrichment of Fe phase is observed in the central layer of the strip, results in the formation of the sandwich structure. Moreover, the as-cast strip of Cu-12Fe was directly cold-rolled from 2.4 to 0.12 mm. The directly cold-rolled sample after aging at 450 degrees C for 16 h (Process I) shows excellent electrical conductivity of 69.5% IACS, the tensile strength and elongation are 513 MPa and 3.8%, the saturation magnetic flux density is 20.1 emug(-1), and the coercive force is 25.2 Oe. In Process II, the as-cast strip firstly cold-rolled to 1.2 mm, then aged at 500 degrees C for 1.5 h, followed by cold rolling to 0.12 mm, finally aged at 450 degrees C for 16 h . The sample after Process II shows the electrical conductivity of 66.3% IACS, the tensile strength of 533 MPa, an elongation of 3.5%, saturation magnetic flux density of 21.4 emug(-1), and the coercive force of 22.3 Oe.
10.1007-s42243-023-01015-2	-1		The microstructures and mechanical properties of the directionally solidified Cu-15Ni-8Sn alloy were investigated at solidification rates ranging from 100 to 3000 & mu;m/s. The results showed that the solidification rate significantly affects the phase distribution of the as-cast Cu-15Ni-8Sn alloy. The primary and secondary dendritic spacing reduces and eventually becomes stable as the solidification rate increases. Meanwhile, the size of the primary phase decreases, and its distribution becomes more uniform. The most severe segregation problem of this alloy has been greatly improved. Upon solidification at 100 & mu;m/s, the as-cast Cu-15Ni-8Sn alloy consists of the & alpha;-Cu matrix, & gamma;-CuNi2Sn phase, discontinuous precipitation structure, modulated structure, and D0(22) ordered phases. However, as the solidification rate increases, the discontinuous precipitation structure, modulated structures, and D0(22) ordered phases decrease and even disappear, reducing hardness. As the solidification rate increases, after homogenization treatment, the composition and microhardness distributions of Cu-15Ni-8Sn alloy become more uniform. The time for homogenization is also shortened. It reduces production energy usage and facilitates further mechanical processing.
10.1007-s42243-023-01076-3	-1		Copper alloy composite bit matrix was prepared by pressureless vacuum infiltration, using at least one of the three kinds of tungsten carbide particles, for example, irregular cast tungsten carbide, monocrystalline tungsten carbide and sintered reduced tungsten carbide particles. The effects of powder particle morphology, particle size and mass fraction of tungsten carbide on the microstructure and mechanical properties of copper alloy composite were investigated by means of scanning electron microscopy, X-ray diffraction and abrasive wear test in detail. The results show that tungsten carbide morphology and particle size have obvious effects on the mechanical properties of copper alloy composites. Cast tungsten carbide partially dissolved in the copper alloy binding phase, and layers of Cu0.3W0.5Ni0.1Mn0.1C phase with a thickness of around 8-15 & mu;m were formed on the edge of the cast tungsten carbide. When 45% irregular crushed fine cast tungsten carbide and 15% monocrystalline cast tungsten carbide were used as the skeleton, satisfactory comprehensive performance of the reinforced copper alloy composite bit matrix was obtained, with the bending strength, impact toughness and hardness reaching 1048 MPa, 4.95 J/cm2 and 43.6 HRC, respectively. The main wear mechanism was that the tungsten carbide particles firstly protruded from the friction surface after the copper alloy matrix was worn, and then peeled off from the matrix when further wear occurred.
10.1007-s42243-025-01507-3	15	aging; strength; conductivity; electrical conductivity; electrical; mpa; treatment; strengthening; degrees; cu-; cold; precipitation; tensile strength; tensile; iacs	The deformation of Cu-20 wt% Fe alloy wires leads to a significant improvement in mechanical properties and a decrease in electrical conductivity. Simultaneous improvements in strength and conductivity were achieved by intermediate annealing of drawn Cu-20 wt% Fe wires. As the annealing temperature increased, the strength of Cu-20 wt% Fe alloy wire decreased monotonically, but the electrical conductivity first increased and then decreased, reaching its peak value after annealing at 500 degrees C. The decrease in strength is related to dislocation recovery and static recrystallization of Cu and Fe phases, and the increase in electrical conductivity mainly results from the aging precipitation of solid solution Fe. After annealing at 500 degrees C, there was no obvious recrystallization of Cu phase, and many of the nano-Fe particles precipitated from Cu matrix. An annealing temperature of 600 degrees C induced the recrystallization of Cu matrix and an increase in Fe solid solubility, resulting in a decrease in strength and electrical conductivity. Subsequently, the wires annealed at 500 degrees C were drawn to 2 mm. Compared with those of the continuously drawn Cu-20 wt% Fe alloy wires, the deformation ability, strength, and electrical conductivity of Cu-20 wt% Fe alloy wires subjected to intermediate annealing treatment are significantly greater. This is mainly related to the sufficient precipitation of Fe in Cu matrix and the strengthening of refined Fe fibers parallel to the drawing direction.
10.1007-s42823-024-00689-2	17	wear; composites; coating; friction; composite; coatings; surface; tribological; properties; wear resistance; resistance; powder; sliding; matrix; wear rate	To reduce production cost and inhibit the aggregation of graphene, graphene oxide and copper nitrate solution were used as raw materials in the paper. Cu particles were introduced to the graphene nanosheets by in-situ chemical reduction method in the hydrazine hydrate and sodium hydroxide solution, and the copper matrix composite reinforced with Cu-doped graphene nanosheets were fabricated by powder metallurgy. The synthesized Cu-doped graphene was characterized by scanning electron microscopy (SEM), transmission electron microscopy (TEM) and X-ray photoelectron spectroscopy (XPS). The relative density, hardness, electrical conductivity and tensile strength of the copper matrix composite reinforced with Cu-doped graphene were measured as well. The results show that copper ions and graphene oxide can be effectively reduced by hydrazine hydrate simultaneously. Most of oxygen functional groups on the Cu-doped graphene sheets can be removed dramatically, and Cu-doped graphene inhibit the graphene aggregation effectively. Within the experimental range, the copper matrix composites have good comprehensive properties with 0.5 wt% Cu-doped graphene. The tensile strength and hardness are 221 MPa and 81.6 HV, respectively, corresponding to an increase of 23% and 59% compared to that of pure Cu, and the electrical conductivity reaches up to 93.96% IACS. However, excessive addition of Cu-doped graphene is not beneficial for the improvement on the hardness and electrical conductivity of copper matrix composite.
10.1007-s43452-019-0002-z	-1		The effects of service environment and pre-deformation on the fatigue behaviour of 2524 alloy were investigated using scanning electron microscopy (SEM), transmission electron microscopy (TEM), and fatigue tests. The results indicate that the fatigue crack-growth rate (FCGR) of the alloy in an aqueous environment increases with temperature ranging from 0 to 90 degrees C. At the same stress intensity factor range (Delta K), the FCGR of the alloy in an argon environment is the smallest, followed by that in air, and a 3.5% NaCl fog environment, while that in an exfoliation corrosion (EXCO) solution is the largest. A pre-deformation of 2% can significantly enhance the fatigue crack propagation resistance of this alloy in argon, air, and 3.5% NaCl fog environments, while 5% pre-deformation weakens the fatigue crack propagation resistance of the alloy accordingly. The pre-deformation effect on the FCGR of alloy in the EXCO solution environment is limited.
10.1007-s43452-021-00272-w	6	grain; deformation; strain; strength; dislocation; cu-; tensile; size; ecap; grain size; sfe; ductility; hardening; high; stress	In this study, severe plastic deformation (SPD) process of hydrostatic tube cyclic extrusion-compression (HTCEC) was performed through two passes on the commercially pure copper tubes with the purpose of fabricating relatively long ultrafine-grained (UFG) tubes. In HTCEC process, the presence of pressurized hydraulic fluid around the piece plays a key role in the reduction of the friction load and, consequently, in the reduction of required pressing load. In principle, this facilitates the production of long and large tubes. After processing by HTCEC, the mechanical characteristics and microstructure evolution were examined. Microstructure analysis revealed that after the first pass of HTCEC process, an ultrafine cell microstructure with an average size of similar to 993 nm was attained. After two passes of HTCEC, the average size of cells/subgrains was reduced to similar to 340 nm. This was while the average grain size of the annealed sample was 41 mu m. Also, after two passes of HTCEC process, a remarkable increase in the yield strength from 154 to 336 MPa, and the ultimate strength from 223 to 414 MPa was observed. Furthermore, the mean value of microhardness increased from 74 to 149 HV, and a more uniform distribution of microhardness along the thickness was seen, compared to the first pass of HTCEC. Meanwhile, unlike most conventional SPD methods, the value of elongation to failure was slightly lessened from 59.5 to 41.6%. SEM fractography analysis denoted that mostly ductile fracture occurred in the HTCEC-processed samples. In general, two main advantages of HTCEC process can be the production of relatively long ultrafine-grained tubes and the significant increase in the strength and hardness besides a low loss of ductility.
10.1007-s43452-022-00429-1	16	wear; composite; composites; powders; milling; particles; powder; wt; sliding; friction; hardness; matrix; mechanical; surface; properties	A fruitful combination of powder metallurgy and the mechanical alloying route is one of the most promising process for producing advanced Cu-based nanocomposites. In this study, three different material systems, namely, pure copper (Cu), 5 wt% Cr reinforced Cu matrix composites, and 1 wt% Y2O3 reinforced Cu-Cr matrix nanocomposites were synthesized by ball milling method at different milling times. The influence of different ball milling times (0.5, 2, and 4 h) and different types of reinforcements (Cr and Y2O3) on the powder and sintered parts properties were thoroughly analyzed with a holistic approach . The milled powders were then consolidated using a cold press followed by a liquid phase sintering process. Results revealed that the Cr and Y2O3 particles were fractionally dispersed and imbedded in the ductile Cu matrix with respect to increasing milling time. Milling for 4 h of Cu-Cr-Y2O3 powders produced the lowest level of particle size (28 mu m) with reduced and flattened and uniformly distributed reinforcement phases due to intense plastic deformation induced shearing effect and dominant powder-ball-jar collisions. Besides, the ball milling process of the same powders concluded a decrement of crystallite size to 35 nm in concomitant with an increase of lattice strain and dislocation density & x2053; % 0.3 and 0.8 x 10(15) line/m(2), respectively. Brinell hardness of the sample produced by these powders increased from 39 to 95 HB. A & x2053;%145 striking increase of hardness could be attributed to the strong hindrance of high-dense dislocations triggered by several concurrent strengthening mechanisms. Nevertheless, relative density results of sintered samples revealed that the addition of Cr and Y2O3 along with increasing milling time deteriorated the density due to the higher hardness and brittleness of milled powders and accompanying worsened compressibility and sinterability. The source of noticed differences between hardness and density results were discussed within the process-structure-performance framework.
10.1007-s43452-023-00754-z	-1		Recently, space research organizations are interested in investigating multistage deep drawing of Cu-Cr-Zr-Ti alloy sheets for the fabrication of large-depth thrust chamber liners used in cryogenic engine of satellite launch vehicles. Hence, an attempt was made for the first time to design and develop a laboratory scale two-stage deep drawing setup to successfully draw cylindrical cups of solution-treated Cu-0.5Cr-0.05Zr-0.05Ti (wt. %) sheets of 1.7 mm thickness. The finite element (FE) model with Marciniak-Kuczynski forming limit diagram (MK-FLD) was implemented to design the above two-stage deep drawing setup, and two different anisotropic models, namely Hill48 and Barlat89, along with solid and shell element formulations were used to capture the deformation behavior. After setup design, the two-stage deep drawing experiments were conducted, and successful redrawn cups with overall drawing ratio of 2.94 with maximum cup depth of 58.5 mm was achieved. The strain evolution during deformation was analyzed in polar effective plastic strain (PEPS) locus, and it was also observed that the surface roughness of cup wall and corner was significantly increased to 2.73 & mu;m and 3.16 & mu;m, respectively, due to accumulation of plastic strain and evolution of texture. Further, the orientation gradient inside the grains at both cup wall and corner regions was observed, and evolution of Copper {112} < 111> and Y{111} texture components were identified in the cup wall. However, the marginal increase in roughness of cup corner as compared to that of the cup wall might be due to the development of Brass {110} < 112 > texture. Finally, the aging behavior of redrawn cup wall was analyzed, and it was found that the peak aging occurred at 500 & DEG;C for 2 h . with a hardness of 98 & PLUSMN; 4 VHN due to the formation of fine Cr-rich precipitates.
10.1007-s43452-024-00981-y	-1		Cu/Sn-Pb multilayer composite was fabricated by accumulative roll bonding (ARB) technique and its structural, mechanical, and corrosion properties were studied. Microstructural evolution revealed that distribution of Cu and Sn-Pb layers improves by increasing ARB passes and multilayer composite with wavy microstructure and formation of Cu6Sn5 intermetallic compound by solid-state reactions was achieved, while tensile test depicted that tensile strength and fracture strain decrease after the first ARB pass. However, the strength of the multilayered composite at the first pass (about 300 MPa) is much higher than that of the pure Cu (about 200 MPa). Electrochemical tests (potentiodynamic polarization) were conducted in 3.5 wt% NaCl and boiler feed water (BFW) on the surface and cross-sectional areas. Open circuit potential (OCP) of the composite was lower than that of the pure and ARBed Cu (pure Cu was fabricated using ARB process after seven passes). The results demonstrated that corrosion resistance on the surface and cross-sectional area decreased with increasing ARB passes, indicating a growing susceptibility to corrosion on both surfaces. Besides, with increasing ARB passes a more uniform distribution of Sn-Pb within Cu matrix was realized and due to the conversion of galvanic coupling to micro-galvanic coupling corrosion occurs more uniformly.
10.1007-s43452-025-01279-3	-1		The CuCrZr alloy is utilized as a power transmission component in microelectronics applications. Notably, nano-sized wear primarily occurs during the charging process of microelectronics. This study investigated the nanowear characteristics of the LPBF CuCrZr alloy when subjected to varying operational load conditions. The aging process was conducted at temperatures of 250 degrees C, 450 degrees C, and 650 degrees C for a duration of 120 min. The specimens aged at 250 degrees C exhibited a closely packed columnar structure, while the specimens aged at 450 degrees C and 650 degrees C developed an equiaxed structure. In addition, nanohardness tests were performed on all three specimens using loads of 2500 mu N, 5000 mu N, and 7500 mu N. The analysis indicated that the columnar structure from the 250 degrees C aging exhibited an equivalent reaction to the indenter, resulting in material piling up. In contrast, the equiaxed structure in the specimens aged at 450 degrees C and 650 degrees C compressed more and showed less reaction against the indenter. A nanowear test at a constant load of 3500 mu N was also conducted on all three aging specimens. The results showed that the equiaxed structure from the 650 degrees C aging was unable to resist the tangential force of the indenter due to local shear. However, the closely packed columnar structure from the 250 degrees C aging effectively opposed the tangential force, leading to the formation of abrasive grooves on the worn surface. Furthermore, the coefficient of friction decreased with increasing aging temperature. The wear mechanisms identified included two-body and three-body abrasive wear at the 250 degrees C aging specimen, while the ploughing wear mechanism was observed in the specimens aged at 450 degrees C and 650 degrees C.
10.1016-0029-5493(95)01140-4	4	transformation; martensite; martensitic; phase; shape; beta; memory; shape memory; temperature; temperatures; martensitic transformation; gamma; transformation temperatures; effect; thermal	Energy balances of pseudoelastic behaviour of a shape memory alloy are experimentally determined using IR techniques. In fact, these balances, established for Cu-Zn-Al alloy at constant room temperature and under quasi-static tensile conditions, allow us to study the relative importance of the intrinsic (mechanical) dissipation involved in austenite-martensite phase changes compared with thermomechancial couplings. An analysis of the experimental data shows that the thermoelastic austenite-martensite phase transition can be considered as a non-isothermal process involving no or little (hardly measureable) mechanical dissipation. Assuming a non-dissipative phase transition, numerical simulations are done in the case of non-isothermal processes using two existing models. This numerical exercise gives mechanical, thermal and energetic responses that can be qualitatively compared with those obtained experimentally. These results evidence that an intrinsic dissipation is not necessary to describe the pseudoelastic behaviour. In general, this example emphasizes once again that thermal and mechanical analyses should be carried out jointly to characterize properties of materials.
10.1016-0039-6028(95)01205-2	-1		The theoretical segregation isotherm in CucPd1-c(111) has been studied both in the disordered and in the ordered state within an energetic model derived from the electronic structure. A segregation reversal is obtained as a function of the bulk concentration in the disordered state. In the ordered state, we obtain a great variety of surface critical behaviours: whereas the bulk order-disorder or order-order transitions are of first order, the surface ones can be of first or second order. In this last case, a wetting behaviour is shown.
10.1016-0169-4332(95)00526-9	-1		Atom-probe field-ion microscopy (APFIM) is used to measure quantitatively the absolute values of the Gibbsian interfacial excess of Ag, Gamma(Ag), at semi-coherent {222} MgO/Cu(AE) heterophase interfaces. Atomically clean metal oxide/metal heterophase interfaces were obtained by internal oxidation of a pure ternary Cu(Mg,Ag) single-phase alloy to produce octahedral-shaped MgO precipitates, 10 to 30 nm in diameter, in a single-phase Cu(Ag) matrix. Precipitates are faceted on {222} planes. Random-area APIM analysis was performed in the [111] direction of the Cu(Ag) matrix, perpendicular to one pair of {222} facets of every MgO precipitate. For a single precipitate dissected on an atomic scale, segregation levels at both ''front'' and ''rear'' interfaces are determined. The average measured value of Gamma(Ag), at 500 degrees C, is (2 +/- 0.6) X 10(15) atoms cm(-2). This corresponds to about one monolayer coverage.
10.1016-0169-4332(96)00235-8	-1		The changes included in the surface composition of a Cu-Zr (50 at%) alloy by Ar+ ion bombardment has been studied using ion scattering spectroscopy (ISS), Auger electron spectroscopy (AES) and X-ray photoelectron spectroscopy (XPS). ISS results indicate that the outermost atomic layer is Zr-rich, comprising 85+/-5%, whereas AES and XPS gives that the subsurface is also Zr-rich, comprising 70+/-3%. These results suggest that the Ari ion bombardment induces an altered layer in depth in which Zr concentration approach exponentially to the bulk concentration with a quite large decay length . This phenomenon is quite different compared to other alloys having a concentration dip occurring in the uppermost atomic layer. The results of elevated temperature experiment clearly shows that Zr atoms are thermally segregating to the uppermost atomic layers. The Zr-rich in the uppermost atomic layer can be explained in terms of preferential sputtering and radiation induced surface segregation effects.
10.1016-0304-8853(95)01169-2	9	magnetic; magnetization; magnetoresistance; temperature; superparamagnetic; annealing; gmr; field; magnetic properties; ferromagnetic; granular; samples; magnetic field; melt-spun; particles	The temperature dependence of the magnetization in nanocrystalline Cu0.5Fe0.5-xCox (x = 0.0, 0.1, 0.2, 0.4) powders, manufactured by mechanical alloying in a high-energy ball mill, has been studied by means of magnetometry and ferromagnetic resonance experiments. The Curie temperatures of the solid solutions increase with Co content. The spin wave stiffness constant and the range of the exchange interaction increase with increasing Co content, indicating the hardening of the exchange interaction by Co substitution.
10.1016-0924-0136(96)02388-6	-1		Rolling and compression tests were carried out to determine the effect of hot working variables-strain, strain rate and temperature-and the initial microstructure on microstructure evolution (grain size and recrystallization kinetics) for some copper and aluminium materials. There are considerable deviations due to the different types of microstructures and the stacking fault energy of Cu and Al. While Cu materials show a strong tendency towards recrystallization due to their low stacking fault energy, recovery prevails for Al materials with their relatively high stacking fault energy. Therefore, the recrystallization processes cannot be assessed on the basis of flow curves as for Cu materials. For a limited number of tests, a mathematical model of the microstructure can be derived for copper materials.
10.1016-0927-0256(95)00072-0	-1		The yield strength of wire drawn in-situ composites consisting of a face centered cubic (fee) metal matrix (Cu) and 5-30 mass% of a body centered cubic (bcc) transition metal (Nb) is modelled by using a modified linear rule of mixtures (MROM). This approach analytically describes the yield strength of the composite as the sum of the volumetric weighted average of the experimentally observed yield strengths of the individual pure phases and a Hall-Fetch type contribution arising from the impact of internal boundaries. The latter portion is described in terms of dislocation pile-ups in the fee matrix and the activation of dislocation movement in the bcc filaments.
10.1016-0965-9773(95)00304-5	9	magnetic; magnetization; magnetoresistance; temperature; superparamagnetic; annealing; gmr; field; magnetic properties; ferromagnetic; granular; samples; magnetic field; melt-spun; particles	We present the field and temperature dependencies of the magnetoresistance in melt spun Cu86Co14 and Cu92Co8 ribbons nanocrystallized by annealing them at higher temperatures. It is found that the giant magnetoresistance, GMR, values measured at 5K, 77K, and room temperature scale as a function of B/(T+ theta) in the regime where the nanocrystals are superparamagnetic. Furthermore, by taking into account the evolution of the magnetic properties of the nanocrystals with annealing, all the GMR data are found to be collapsible to a universal function, with the Langevin variable mB/(T+theta), where m is a scaling factor dependent on the magnetic property of the annealed state.
10.1016-j.acme.2019.03.009	-1		To overcome some possible deficiencies of pure copper, dilute alloying and employment of equal channel angular pressing seem the cost-effective solutions. In this work, dilute copper alloys with the tin amount of 0.18, 0.3, and 0.5 wt% were obtained with continuous casting and subsequently, they were subjected to ECAP process up to four passes. It was shown that integrated treatment by dilute alloying and ECAP lead to 182% improvement of the corrosion resistance as compared to the as-received condition due to the grain refinement. Meanwhile, the alloying impact on current density is decreased with the ECAP process which may result from the changes at the distribution of Sn atoms in Cu. The difference in measured corrosion current density of unprocessed and ECAPed samples for the alloys Cu-0.3% Sn and Cu-0.5% Sn are 15% and 2%, respectively. The corrosion improvement by means of current density reduction due to the alloying before the ECAP process is about 45% while this value after the ECAP diminishes to 35%. Microstructure analysis showed that four passes of ECAP process cause the average grain size of the pure copper to less than 700 nm and the Cu-0.5% Sn to about 550 nm. Also, the HAGBs fraction of the ECAPed pure Cu is 74%, while the corresponding magnitude for the Cu-0.5% Sn is 78%.
10.1016-j.actaastro.2024.12.010	14	strength; properties; conductivity; electrical; mechanical; cu-; grain; mpa; electrical conductivity; aging; precipitation; phase; mechanical properties; tensile; phases	This study demonstrates the potential of single-crystalline Cu-Al-Mn shape memory alloys (SMAs) for use as smart actuators in deployable thermal radiators, aiming to reduce spacecraft costs and weight. The SMA actuators are designed to axially displace via buckling to half of their initial length, minimizing storage space and maximizing deployment stroke. Slender polycrystalline, near-oligocrystalline, and single-crystalline Cu-Al-Mn SMA samples were fabricated using a cost-effective cyclic heat-treatment process and subjected to 100 cycles of large-displacement axial compression testing in superelastic mode. The performance was evaluated based on deformation uniformity, length recoverability, and end-load stability. Single-crystalline samples, with a tensile transformation strain of approximately 6.0%, exhibited symmetrical post-buckling deformation, over 90% length recoverability, and stable end-load behavior. In contrast, near-oligocrystalline samples, with grain sizes comparable to or larger than their width and thickness, demonstrated the largest tensile transformation strain ( 8.0%) but exhibited asymmetrical deformation and highly inconsistent performance. Finite element analysis indicated that this behavior resulted from nonhomogeneous martensitic transformation and asymmetrical stiffness due to weakly constrained grains with varying transformation stresses. Polycrystalline samples, with smaller grain sizes relative to their width and thickness, exhibited symmetrical deformation but showed the smallest tensile transformation strain ( 2.0%), leading to the lowest length recoverability. These findings underscore the importance of considering both transformation behaviors and the grain-size-to-sample-dimension ratios when optimizing the performance of slender SMA structures operating in post-buckling modes.
10.1016-j.actamat.2004.01.022	4	transformation; martensite; martensitic; phase; shape; beta; memory; shape memory; temperature; temperatures; martensitic transformation; gamma; transformation temperatures; effect; thermal	Like in the plasticity theory, the prediction of phase transformation yield surfaces constitutes an essential issue in the modelling of polverystalline shape memory alloys thermornechanical behaviour. Usually for micro-macro integration, the nature of the interface between austenite and twinned or untwinned martensite under stress free state and the choice of correspondence variants (CV) or habit plane variant (HPV) are predominant toward the explicit shape of the phase transformation surface. If the predictions for Cu-Al-Be, Cu-AI-Zn (interface between austenite and one single variant of inartensite for cubic to monoclinic phase transformation) and Cu-Al-Ni (interface between austenite and twinned martensite for cubic to orthorhombic phase transformation) are fairly good; the prediction is not efficient in the important case of Ti-Ni (interface between austenite and twinned martensite with stress free state for cubic to monoclinic phase transformation). The usual hypothesis consisting in neglecting the effect of stress on the interface geometrical configuration must be revised.
10.1016-j.actamat.2004.03.010	4	transformation; martensite; martensitic; phase; shape; beta; memory; shape memory; temperature; temperatures; martensitic transformation; gamma; transformation temperatures; effect; thermal	Two concurrent mechanisms of thermal stabilization of martensite have been distinguished in a Cu-21.3wt%Zn-5.4wt%Al-0.05wt%B alloy: kinetic stabilization, occurring during the reverse martensitic transformation and associated with sweeping-up of quenched-in defects by moving interfaces; swept-up quenched-in defects inhibit the motion of interfaces similar to the dynamic strain ageing effect; static stabilization, associated with isothermal ageing in the martensitic state. These stabilization mechanisms demonstrate opposite dependences on the duration of martensite ageing: the kinetic stabilization is suppressed by martensite ageing, whereas the static component is promoted by martensite ageing. The kinetic stabilization can be strongly predominant over the static one so as to cause only partial reverse transformation for short martensite ageing periods. In that case, the reverse transformation becomes more complete with martensite ageing. The suppression of kinetic stabilization with martensite ageing reflects a dramatic modification of the system of quenched-in defects upon martensite ageing, which includes either vanishing of the defect-assisted diffusion of quenched-in defects or a redistribution of quenched-in defects in the bulk of the sample. The origin of such redistribution can be pinning of interfaces at their static positions, responsible for the static pinning-induced stabilization component. The kinetic stabilisation also exemplifies pure pinning mechanism of stabilization, related, in contrast to static pinning, to immobilisation of moving interfaces.
10.1016-j.actamat.2004.05.009	4	transformation; martensite; martensitic; phase; shape; beta; memory; shape memory; temperature; temperatures; martensitic transformation; gamma; transformation temperatures; effect; thermal	The dependence of martensitic transformation characteristics on the type (beta', gamma' or beta' + gamma') of thermally induced martensite has been studied in Cu-Al-Ni shape memory alloys. The energy balance of the martensitic transformation (MT) has been analyzed for the three possible transformations by calorimetric measurements. When a single MT, beta --> beta' or beta --> gamma' is present, the dissipative term linked to the irreversible entropy Si has been evaluated. This term that accounts for the hysteresis is higher for the beta --> gamma' transformation than for the beta --> beta' one, according to the hysteresis behavior. On the other hand, during mixed beta --> gamma' + beta' transformation, a higher irreversible entropy and a negative total exchanged heat have been measured. In order to explain this behavior, a modification of the energy balance, which takes into account the presence of plastic deformation when martensite coexistence occurs, has been proposed.
10.1016-j.actamat.2004.10.042	-1		A copper-iron carbide nanocomposite has been synthesized by high-energy milling of elemental powders (CU69-Fe-23-C-8), followed by annealing at 873 K. Phase identification and microstructure characterization have been carried out by transmission electron microscopy and energy dispersive spectroscopy. The carbide phase found in the as-milled material has been identified as Fe3C and/or Fe7C3, but clearly only Fe3C was present after annealing. Overall, grain sizes ranged from 10 to 50 nm in the as-milled condition and from 30 to 160 nm after annealing, with the carbide phase presenting a higher growth rate than copper. Stacking faults and a dispersion of Cu nanoparticles (5-10 nm) have been detected in annealed cementite while copper grains exhibited twins on {1 1 1 } planes. Cementite growth could be evaluated in terms of precipitate growth theory. The remarkable thermal stability of the copper matrix is proposed to be related to solute drag effects.
10.1016-j.actamat.2004.11.019	-1		The initiation and growth of discontinuous precipitation (DP) at [0 1 1] symmetric tilt boundaries in Cu-0.75 wt% Be alloy bicrystals have been studied. Transmission electron microscopy revealed that gamma precipitates tended to nucleate at a boundary in such a manner that their habit plane, {112}(alpha) or {445}(alpha), with one of the adjoining grains lay as close as possible to the boundary. The habit plane with a low energy formed on both sides of the precipitates behind an initially migrating boundary, indicating the importance of the existence of the low-energy habit plane for the initial boundary migration. The incubation period to initiate DP and cell growth rate for a boundary show a good correlation with the energy of the boundary. A kinetic analysis of DP using the models of Turnbull, and Petermann and Hornbogen has yielded boundary diffusion data. A higher-energy boundary has a higher diffusivity with a smaller activation energy.
10.1016-j.actamat.2004.12.019	4	transformation; martensite; martensitic; phase; shape; beta; memory; shape memory; temperature; temperatures; martensitic transformation; gamma; transformation temperatures; effect; thermal	A heterophase fluctuation of omega (omega) phase in the body-centered cubic matrix is studied by evaluating the reciprocal free energy modulus which includes the properties of coherent strain energy and the bulk free energy change. As a consequence, analytical expressions are obtained for the concentration, dimensions and distribution of heterophase omega clusters. The incommensurate to cluster having a dual phase (omega and beta) structure is suggested to form in the heterophase fluctuation. On the basis of the theoretical analysis of the distribution of to clusters, quantitative calculation of diffuse intensity of X-ray diffraction was carried out for the Cu-Zn system. The estimated diffuse intensities I(h)/I-0 are in good agreement with the experimental results: the offset of the diffuse intensity peak and ellipsoidal shape of the intensity having streaks towards the nearest fundamental spot. The diffuse peak of X-ray diffraction is manifested to behave like a central phonon peak of heterophase fluctuation as T/(T-T-0) where T-0 is the coherent transformation temperature.
10.1016-j.actamat.2005.01.046	-1		The effect of strain path during severe plastic deformation via equal-channel angular pressing on grain refinement and structural features of a model Cu-Cr alloy is investigated in terms of grain shape, dimensions, preferred crystallographic orientation and distribution of grain boundaries with respect to the angle of misorientation. The mechanical behavior of differently processed specimens is assessed in both monotonic and cyclic tests aimed at clarification of the role played by different structural factors in the resultant mechanical properties. It is shown, that despite the considerable microstructural differences in the grain morphology and texture, the tensile and fatigue strength is only slightly affected by the processing routes chosen in the present study. However, the strain path and, therefore, the grain shape and texture have some effect on ductility and strain localization, which is particularly pronounced during cyclic loading.
10.1016-j.actamat.2005.04.013	4	transformation; martensite; martensitic; phase; shape; beta; memory; shape memory; temperature; temperatures; martensitic transformation; gamma; transformation temperatures; effect; thermal	Elastic constants of cubic austenite and orthorhombic 2H martensite phases in the Cu-Al-Ni shape memory alloy were determined by ultrasonic pulse-echo technique using multiple single crystal specimens and a novel optimization based evaluation method that minimizes the uncertainty stemming from experimental errors as well as experimental effort. Multiple martensitic single crystals were prepared from the austenite crystal by a dedicated deformation technique. Taking advantage of the fact that the elastic constants of the austenite and 2H martensite phase were evaluated on the same piece of material, soft acoustic modes and elastic properties of both phases were compared taking into account the lattice correspondence. It is found that the 2H martensite crystal partially inherits the soft acoustic modes of the austenite and hence its elastic properties.
10.1016-j.actamat.2005.05.013	1	shape; memory; shape memory; damping; martensite; martensitic; damping capacity; transformation; capacity; strain; superelasticity; temperature; cu-al-mn; shape memory effect; effect	The effect of the relative grain size d/D (d. grain size, D: wire diameter) on stress-strain characteristics was investigated in Cu-Al-Mn-based shape memory alloy (SMA) wires. The yield stress (sigma(y)), the work-hardening rate after yielding (d sigma(PE)/d epsilon) and the stress hysteresis (Delta sigma) in the wires with a random texture decrease with increasing d/D. The transformation strain (epsilon(TS)) and the maximum pseudoelastic strain (epsilon(PE)(MAX)) increase with increasing d/D. The effect of grain size on pseudoelastic behaviors can be clarified from the PE volume fraction of three-dimensionally constrained grains and the sigma(y), d sigma(PE)/d epsilon and Delta sigma increase proportionally with increasing (1-(d/D))(2) while the epsilon(TS) decreases proportionally with increasing (1-(d/D))(2). Consequently, the effect of grain size on the pseudoelastic behaviors can be expressed using the Taylor and inverse Schmid factors. The sigma(y) and the epsilon(TS) for wires with a < 110 > fiber texture are larger and smaller than those for wires with a random texture, respectively.
10.1016-j.actamat.2005.06.017	-1		Microstructural parameters of plastically deformed (hand filed) Cu-ISn-Zn ternary alloys with zinc concentration 10-24 wt% are studied with X-ray diffraction line profile analysis. It is observed that unlike the binary alloy system, the stacking fault probability calculated from peak shift analysis is almost constant with increase in zinc concentration from 10 to 20 wt% and thereafter increases with the increase of zinc concentration. Stacking fault energy is calculated by modifying the expression given by Reed and Schramm [J Appl Phys 1974;45:4705] and shows a significant difference with that from earlier work by Ghosh and Sen Gupta [J Appl Phys 1983 54:6652]. Present results are closer to electron microscope studies. It is found that dislocation density is much higher (similar to 10(15) m(-2)) and shows compositional dependence. Dislocation type is found to be a combination of equal populations of screw and edge dislocations. It is noticed from dislocation arrangement parameters that the dislocations are greatly correlated in nature for lower Zn concentration and less correlated at higher Zn concentration.
10.1016-j.actamat.2005.10.019	12	thermodynamic; ternary; phase; data; experimental; equilibria; phase equilibria; liquid; binary; experimental data; calculated; phases; literature; model; calphad	Thermodynamic assessment of the Cu-Zr binary system was carried out using thermodynamic data obtained over a wide range of temperatures. The associated solution model was applied to describe the short range ordering in a liquid. The glass transition was treated as a second order transition with Hillert-Jarl functions. The driving force for crystallization and time-temperature-transformation (TTT) curves were estimated from the optimized parameter set, and compared with experimental data and the results of previous thermodynamic assessments. Taking into account thermodynamic data at low temperatures, the calculated driving force was found to be lower than the results of previous assessments. Consequently, the nose of the TTT curve was shifted to a longer time.
10.1016-j.actamat.2005.12.020	-1		Enhancement of plasticity and the occurrence of liquid-state phase separation have been investigated by partially substituting Zr with Y in Cu46Zr47-xYxAl7 (x = 0, 2, 5, 10, 15, 20, 25, 30, 35) alloys. Since Y has a positive enthalpy of mixing with Zr (+35 U/mol) in the liquid state, the alloy composition moves to the metastable miscibility gap of the two amorphous phases with increasing Y content. Phase separation into Y-rich and Zr-rich amorphous phases occurs during cooling from the liquid state when the Y content is above 15 at%. The bulk amorphous alloys consisting of two phase-separated amorphous phases exhibit extreme brittleness, while the single-phase amorphous alloys containing 2-5 at% of Y exhibit enhanced plasticity because of the introduction of chemical inhomogeneity in the amorphous matrix. The results indicate that the addition of an element having a positive enthalpy of mixing with the constitutive element in bulk amorphous alloys can increase the plasticity as well as the glass-forming ability, but for a limited composition range.
10.1016-j.actamat.2005.12.035	4	transformation; martensite; martensitic; phase; shape; beta; memory; shape memory; temperature; temperatures; martensitic transformation; gamma; transformation temperatures; effect; thermal	An attempt is undertaken to define a factor, apart from temperature, which allows for the mobility of quenched-in defects in a Cu-Al system of martensitic alloys. Experiments were performed with single-and polycrystalline alloys with nominal Al content ranging from 10 to 13.5 wt%. An acoustic technique, operating for temperatures ranging from ambient down to 10 K, was applied to detect the existence of mobile quenched-in defects. No mobility of quenched-in defects was detected for either single-or polycrystalline alloys with Al contents close to and below the Cu3Al stoichiometric one (Cu-12.4 wt% Al), corresponding to perfect DO3 ordering. For the alloy Cu-13 wt% Al, mobility of quenched-in defects was detected starting from temperature of around 70 K. It is suggested that the off-stoichiometry of the alloys is accommodated through anti-site defect formation on the M-deficient side and through vacancy formation on the Al-rich side of the phase diagram. The composition dependence of damping of Cu-Al martensites exhibits a sharp maximum around the stoichiometric composition Cu3Al (Cu-12.4 wt% Al), which is presumably formed by variations of ordered domain size and point defect concentration on both sides of the stoichiometry.
10.1016-j.actamat.2006.07.008	6	grain; deformation; strain; strength; dislocation; cu-; tensile; size; ecap; grain size; sfe; ductility; hardening; high; stress	The evolution of microstructure and the mechanical response of copper subjected to severe plastic deformation using equal channel angular pressing (ECAP) was investigated. Samples were subjected to ECAP under three different processing routes: B-C, A and C. The microstructural refinement was dependent on processing with route B-C being the most effective. The mechanical response is modeled by an equation containing two dislocation evolution terms: one for the cells/subgrain interiors and one for the cells/subgrain walls. The deformation structure evolves from elongated dislocation cells to subgrains to equiaxed grains with diameters of similar to 200-500 nm. The mis-orientation between adjacent regions, measured by electron backscatter diffraction, gradually increases. The mechanical response is well represented by a Voce equation with a saturation stress of 450 MPa. Interestingly, the microstructures produced through adiabatic shear localization during high strain rate deformation and ECAP are very similar, leading to the same grain size. It is shown that both processes have very close Zener-Hollomon parameters (In Z similar to 25). Calculations show that grain boundaries with size of 200 nm can rotate by similar to 30 degrees during ECAP, thereby generating and retaining a steady-state equiaxed structure. This is confirmed by a grain-boundary mobility calculation which shows that their velocity is 40 nm/s for a 200 nm grain size at 350 K, which is typical of an ECAP process. This can lead to the grain-boundary movement necessary to retain an equiaxed structure.
10.1016-j.actamat.2006.07.036	-1		The mechanical properties of polycrystalline Cu (purity 99.95%) prepared by severe plastic deformation were studied at low homologous temperatures from 0.5 K to room temperature. Material with three different microstructures was prepared by annealing of ultrafine-grained Cu. At cryogenic temperatures (0.5 and 4.2 K) the material exhibited an inverse temperature dependence of the yield stress and unstable plastic deformation accompanied by serrations on the stress-strain curves. These low-temperature anomalies were accentuated with grain refinement. At cryogenic temperatures, enhanced ductility was observed and the Hall-Petch relation was found to hold. Microhardness and yield stress were much more temperature dependent in fine-grained than in coarse-grained material, and there is a correlation between the flow stress at a fixed strain and the microhardness. This study has demonstrated that, apart from enhanced discontinuous plastic flow, severe plastic deformation improves the strength of copper at cryogenic temperatures without sacrificing ductility.
10.1016-j.actamat.2006.08.030	-1		The grain boundary segregation in an Cu-50 at.ppm Bi alloy annealed at two temperatures and tinder various hydrostatic pressures in a hot isostatic pressing apparatus was investigated by means of Auger electron spectroscopy. It was found that high pressures have only little effect on grain boundary segregation. At a temperature of 973 K the segregation level remained approximately constant at 2 mono-layers of Bi for all pressures studied. Some decrease of the grain boundary segregation with increasing pressure was observed at 1173 K. It was also demonstrated that the segregation level in the alloy treated at 0.01 GPa depended on the sample cooling rate after annealing. The observed pressure dependence of Bi segregation to the grain boundaries was interpreted in terms of non-equilibrium segregation during specimen cooling.
10.1016-j.actamat.2007.03.021	6	grain; deformation; strain; strength; dislocation; cu-; tensile; size; ecap; grain size; sfe; ductility; hardening; high; stress	The texture and grain boundary structure of recrystallized materials are dependent upon the character of the deformed matrix and the selective nucleation and growth of crystallites from the deformation structure. Annealing twin boundary formation in materials of low to medium stacking fault energy is not only a product of the recrystallized structure, but also plays an important role in the recrystallization process itself. In situ and ex situ recrystallization experiments were performed on pure copper (99.99% pure) previously deformed by equal channel angular extrusion. Intermittent characterization of the structure on the surface of bulk specimens was accomplished using electron backscatter diffraction. The character of the structure where nucleation preferentially occurs is presumed to be in heavily deformed regions as nuclei were first observed in such microstructures as viewed from the specimen surface. Grain growth is observed to be heavily dependent upon twinning processes at the low temperatures used for in situ experiments, with twinning occurring to aid the recrystallization process. It is shown at these temperatures that the slowest growing grains obtain the highest fraction of twin boundaries as the new twin orientations presumably increase the boundary energy at positions where there is insufficient driving force to Continue growth .
10.1016-j.actamat.2007.04.025	-1		Cu-Ta bulk nanocomposites with varying amounts of Ta were produced by high-energy ball milling followed by compaction and sintering. The final crystallite size of Cu and Ta during the high-energy ball milling depends on the deformation behavior of the Cu-Ta composite rather than the melting point of the elements. The grain size of the nanocomposites after sintering is less than 100 run. The Cu-Ta nanocomposites showed a superior sintering behavior compared with the microcomposites. The hardness and compressive strength of the Cu-Ta nanocomposites are 3.6-3.8 and 3.6-5 times higher than that of the microcomposites, respectively. The electrical resistivity of the nanocomposites is slightly higher than that of the microcomposites. However, the normalized hardness to resistivity ratio of the nanocomposites is higher than that of the microcomposites, which signifies that it is the increase in hardness rather than in resistivity that is predominant. A major contribution to the strength of the nanocomposite comes from the nanocrystalline grain size of Cu, in accordance with the Hall-Petch relation.
10.1016-j.actamat.2007.05.034	-1		The distribution of segregation levels of bismuth to grain boundaries in copper has been measured and compared using Auger electron spectroscopy (AES) and X-ray energy-dispersive spectroscopy (XEDS) in a scanning transmission electron microscope (STEM). The STEM-XEDS measurements showed that there are large numbers of grain boundaries with very low segregation levels which, as they are not embrittled, are not analysed using AES. A crystallographic analysis of a small number of boundaries showed that low segregation levels were not necessarily associated with special, high symmetry boundaries. These results indicate that only a part of the segregation behaviour can be explained by any results obtained using AES and that understanding the relationship between crystallography and brittle behavior will require going beyond a misorientation analysis.
10.1016-j.actamat.2007.12.052	-1		We report here on 90 at% copper 2-4 mm thick castings with fracture strengths up to 1.9 MPa due to the formation of a thick, scratch-resistant nanocrystalline chill-zone next to the copper mold contact surfaces. It is found that the unusually hard nanocrystalline surface layers of thicknesses in the range of 200-300 mu m form when the melt can be undercooled: when the alloy composition is such that the contact surface of the copper mold with the liquid alloy does not serve as a preferred site for crystal nucleation, supercooling of the melt in the chill-zone is possible. These castings are the hardest coppers ever reported to date in macroscopic specimens. They have mechanical strength superior to those of many stainless steels as well as to Cu-Be alloys and of the order of those of Cu-based bulk metallic glasses (BMGs) of similar dimensions. In addition, and unlike in copper-based BMGs, the color and luster can be tailored by elemental additions to vary from copper-like to gold-like.
10.1016-j.actamat.2008.02.040	-1		The microstructure of the transfer layer, and the underlying severely plastically deformed layer (SPDL), formed during the dry sliding of a spinodally hardened Cu-15 wt% Ni-8 wt% Sn bronze against a stainless steel, is characterized at the nanoscale by conventional and analytical transmission electron microscopy, including energy-dispersive spectroscopy and electron energy loss spectroscopy. The SPDL consists of a Cu-Ni-Sn solid solution with elongated nanograins, due to extensive dislocation glide and twinning. In contrast, the transfer layer, 2-3 mu m thick, is an equiaxed nanocomposite comprised of a Cu-rich metallic phase with a (Fe,Cr)(2)O-3-based oxide precipitates, and forms as a result of the mechanical mixing and compaction of wear debris. The bronze in this layer has undergone dealloying, indicative of the importance of thermal effects. The dispersion of oxide in the transfer layer suggests a different type of forced mixing, possibly turbulent mixing. The transfer layer is observed to improve significantly the wear resistance of the bronze.
10.1016-j.actamat.2008.02.044	-1		The present study reports the effect of the addition of Be in Cu-Zr bulk metallic glass (BMG) on glass-forming ability (GFA), plasticity and structural change. Although Be has a negative enthalpy of mixing with all the constituent elements of these glasses, CU47.5Zr40Be12.5 alloy exhibits apparent double glass transitions (T-g) and enhanced plasticity as well as improved GFA. Intensive structural analysis using extended X-ray absorption fine structure suggests that a large difference in the enthalpy of mixing between atom pairs in multi-component BMGs can cause atomic scale structural inhomogeneity and/or locally favored structures in the amorphous matrix, resulting in enhanced compressive strains, although the enthalpies of mixing for atom pairs are all negative. This concept may shed light on the development of BMGs with large plasticity as well as high GFA.
10.1016-j.actamat.2008.05.028	4	transformation; martensite; martensitic; phase; shape; beta; memory; shape memory; temperature; temperatures; martensitic transformation; gamma; transformation temperatures; effect; thermal	This paper reports on the pseudoelastic, isothermal mechanical cycling of copper-aluminium-nickel single-crystals. It was found that stress-free transformation temperatures at the end of 1000 stress cycles did not change, whereas the transformation stresses decreased by about 10%; otherwise, the overall strain of 7% imposed during a loading cycle was completely recovered at the end of 1000 cycles. Noncontact multi-video extensometry uncovered a significant spatial non-uniformity in the maximum strains attained in different sections of the wire, At the end of the 1000th cycle. the top and bottom sections demonstrated very similar maximum strains while the midsection demonstrated lower strain. Phase quantification of the midsection of the wire using neutron diffraction demonstrated an increase in the stabilization of austenite from 0% in the first cycle to about 60% in the 1000th cycle. The specific nature of the tests required by neutron diffraction also uncovered a creep-like response of the SMA. Preliminary investigation suggests that this pseudo-creep is due to the motion of phase fronts during the phase transformation. Neutron diffraction has also confirmed that while the single crystallinity of the SMA is excellent at 175 degrees C, there is it spread in orientation of the cubic phase at 200 degrees C with respect to the axis of the wire that is estimated at 2.17 degrees. This spread disappears/reappears on mechanical loading/unloading, but decreases permanently on cyclic loading.
10.1016-j.actamat.2008.08.059	4	transformation; martensite; martensitic; phase; shape; beta; memory; shape memory; temperature; temperatures; martensitic transformation; gamma; transformation temperatures; effect; thermal	A thermodynamic study, based on high-sensitivity adiabatic calorimetry, of the martensitic transformation undergone by Cu-Al-Ni shape memory alloys is presented. From the specific heat data, the thermodynamic function values, and in particular the crystal free energy, as functions of temperature have been obtained. These results have permitted a careful estimation of the phase transformation temperatures of each beta(3)' martensite plate as function of its stored elastic energy. Within this frame, the distribution density of the elastic energy states in the martensitic phase is directly derived from the specific heat data. It also permits a simple analysis of the nucleation processes and gives a convincing explanation of the temperature memory effects.
10.1016-j.actamat.2009.02.009	-1		The dihedral angle shown by intergranular lead inclusions in Cu-1 wt% Pb alloys is measured varying the purity of the metal and the temperature. Several measurement methods are used and compared, namely classical two-dimensional (2D) methods based on metallurgical cross-section analysis and a recently developed 3D stereoscopic method that yields the true three-dimensional angle value for individual inclusions straddling a flat grain boundary. We confirm and extend earlier measurements using the new method. We show that a discrepancy found between the literature data and the stereoscopic 3D dihedral angle measurements is not caused by impurity effects. Rather, the data indicate that the discrepancy has its origin in a difference in average dihedral angle values measured between inclusions straddling two grains and values found at inclusions located where three or more grains meet.
10.1016-j.actamat.2009.03.027	-1		Recent reports Suggest that Poisson's ratio (v), or the related ratio of shear modulus G to bulk modulus B, indicates the potential of metallic glasses (MGs) to sustain plastic strain. Using molecular dynamics Simulations of the Cu64Zr36 MG as a representative, we demonstrate why and how these elastic and plastic properties are correlated, in terms of the common structural origin underlying these mechanical behaviors in MGs. The full icosahedral ordering has been identified as the key structural feature in the Cu-Zr MGs that controls not only the G and the GIB (or v), but also the initiation of shear localization and the intrinsic plasticity. Additional analysis of the Cu-Zr MGs of different compositions and MGs in different alloy systems reveals a general correlation of the plasticity with the G/B ratio, as the latter is able to represent and couple the effects of both the atomic configuration and the alloy composition.
10.1016-j.actamat.2009.07.030	6	grain; deformation; strain; strength; dislocation; cu-; tensile; size; ecap; grain size; sfe; ductility; hardening; high; stress	Pure, ultrafine-grained (UFG) Cu produced by equal channel angular pressing (route B(C)) at ambient temperature was deformed in uniaxial compression at elevated temperatures up to 418 K = 0.31 T(m) (T(m): melting point). The deformation is accompanied by softening. Analysis of the deformation behavior and microstructural observations provide evidence that the softening is related to homogeneous growth of the subgrain size towards a steady-state value which depends on stress as in materials of conventional grain size and is related to growth of the spacing of high-angle boundaries. The softening can be explained by a recently published dislocation model of deformation of UFG materials. In addition, local coarsening of the structure by recrystallization produces bimodal grain structures and leads to strong softening when the temperature is sufficiently high during slow deformation after prior fast deformation and during annealing.
10.1016-j.actamat.2009.07.042	11	glass; bulk; metallic; bulk metallic; gfa; bmg; glassy; metallic glass; ability; bulk metallic glass; amorphous; addition; crystallization; mm; glass-forming	Cu47.5Zr47.5Al5 rods with different volume fractions of crystalline B2 CuZr phase were prepared by copper mould casting. Based on microstructural investigations a solidification mechanism is proposed for these bulk metallic glass (BMG) composites. The composite microstructure enhances the compressive plasticity (plastic strain up to 14%) and both plastic strain as well as yield strength scale with the crystalline volume fraction. Yield strength and fracture strain were successfully calculated using a strength model, which considers percolation and an empirical three microstructural element body approach, respectively. Furthermore, B2 CuZr was synthesized by means of a thermal cycling treatment and uniaxial compression tests were carried out at room temperature. The intrinsic work-hardenability caused by a martensitic transformation has strong implications on the deformation behaviour of the investigated Cu47.5Zr47.5Al5 BMG composites.
10.1016-j.actamat.2009.07.066	-1		Nano- and micro-scale free volumes in ultrafine grained Cu-1 wt%Pb alloy deformed by equal channel angular pressing (ECAP) were examined by a combination of radiotracer diffusion measurements, transmission electron microscopy, depth milling by focused ion beam, and positron annihilation spectroscopy. The positron lifetime spectroscopy revealed the existence of vacancy-type defects, presumably related to grain boundary states, and vacancy clusters. The positron annihilation sites probed by coincident Doppler broadening spectroscopy are surrounded by both Cu and Pb atoms, implying preferred nucleation of nanovoids near small Pb inclusions. Larger free volume defects, such as nano- and submicron-sized pores and submicrometer cracks, were directly observed by the focused ion beam technique. Ultra-fast penetration of liquid tracer solution in the sample bulk was established in the radiotracer diffusion experiments. The results provide an unambiguous proof of the existence of open porosity in ultrafine grained Cu-Pb alloy deformed by ECAP. Under specific deformation conditions, a connected network of open channels, which promotes long-range penetration of a liquid radiotracer solution, was shown to form during the severe deformation. The relative volume fraction of the percolating porosity was estimated at about 2 x 10(-6).
10.1016-j.actamat.2009.08.003	1	shape; memory; shape memory; damping; martensite; martensitic; damping capacity; transformation; capacity; strain; superelasticity; temperature; cu-al-mn; shape memory effect; effect	The effects of ageing at 473-573 K on the hardness, microstructure and thermoelastic martensitic transformation in Cu-Al-Mn-based shape memory alloys were investigated. It was found that hardness was dramatically increased by ageing due to the formation of fine bainitic plates and that the volume fraction of the bainite phase with ageing time can be described by the Austin-Rickett equation. The martensitic transformation temperatures decreased with the formation of bainite plates, mainly due to the composition change of the beta-matrix. Moreover, the growth of thermally induced martensite plates was disturbed by the existence of bainite plates. Consequently, the transformation intervals (M(s)-M(f) and A(f)-A(s)) and transformation hystereses (A(f)-M(s) and A(s)-M(f)) increased with the progress of bainitic transformation.
10.1016-j.actamat.2009.08.011	1	shape; memory; shape memory; damping; martensite; martensitic; damping capacity; transformation; capacity; strain; superelasticity; temperature; cu-al-mn; shape memory effect; effect	Effects of aging at 473-573 K on stress-induced martensitic transformation for textured Cu(71.9)Al(16.6)Mn(9.3)Ni(2)B(0.2) and random-textured Cu(72.1)Al(16.9)Mn(0.5)Co(0.5) shape memory alloy (SMA) wires with a large relative grain size d/D = 6 were investigated by cyclic tensile testing at room temperature, where d and D indicate mean grain size and wire diameter, respectively. The random-textured Cu(72.1)Al(16.9)Ma(10.5)Co(0.5) wire cannot be uniformly deformed and the ductility is drastically reduced by aging treatment. On the other hand, in the textured Cu(71.9)Al(16.6)Mn(9.3)Ni(2)B(0.2) SMA wire, the critical stress for martensitic transformation sigma(t) and the tensile strength sigma(f) are increased by aging without the associated loss of superelasticity (SE). Even in textured wire with a high sigma(t) of over 750 MPa, an excellent SE strain of about 6% can be obtained due to the formation of a fine bainite phase. Moreover, it was confirmed by in situ observation that stress-induced martensite plates grow, accompanying distortion of the bainite plates.
10.1016-j.actamat.2009.09.047	4	transformation; martensite; martensitic; phase; shape; beta; memory; shape memory; temperature; temperatures; martensitic transformation; gamma; transformation temperatures; effect; thermal	A single crystal with a selected composition of a Cu-Al-Ni shape memory alloy, undergoing two martensitic phase transformations when cooling from the common parent phase, beta(3) -> beta(3)' + gamma(3)', has been studied by adiabatic calorimetry. As the coexistence of two different martensites has a strong influence on the transformation kinetics, both the forward and the reverse phase martensitic transformation have been carefully studied by means of very low thermal rate dynamic thermograms. Temperature memory effects have been observed in the beta(3)' transformation but not in the gamma(3)' one. Finally, radiation-cooling procedures were used to study the forward transformation and showed the interaction between the two types of martensite variants on the nucleation processes. This last technique was found useful to evaluate the latent heat released at each individual nucleation event, throughout the transformation progress. The consequent sample self-heating alters this process, which dramatically affects the beta(3)'/gamma(3)' ratio and the final martensitic state.
10.1016-j.actamat.2009.10.011	-1		Cu-based bulk metallic glass (BMG) coatings were built-up by the atmospheric plasma spraying (APS) process at different hydrogen flow rates. As the hydrogen flow rate increased, thermal energy in the plasma jet increased the melting state of the Cu-based BMG particles. Although it was expected that the difference in melting states would quantitatively affect the amorphous fractions in the coatings, both the amorphous fraction and the oxide content of the layers were independent of hydrogen flow rate. However, different melting states resulting from different hydrogen gas flow rates, and the subsequent oxidation which inevitably occurred during spraying, generated different crystallization processes in the coating. In this paper, crystallization mechanisms in plasma-sprayed BMG were studied using their microstructures. Specific analyses of the particles deposited at high travel speed and quenched in cold water also served for further understanding of the melting state and change in composition of the particles undergo during deposition.
10.1016-j.actamat.2009.12.004	-1		First-principles calculations and experimental methods were employed to investigate the relative stability of intermetallic phases in the Cu-Zr system. Computed enthalpies of formation indicate that Cu51Zr14-beta and CuZr2-C11(b) are stable phases, while Cu-Zr-5-C15(b), Cu10Zr7-phi and CuZr-B2 are metastable at 0 K. Heat treatment and microanalysis revealed two important findings which clarify the phase equilibria. First, the stability range for the Cu5Zr-C15(b) phase was found to have a lower bound associated with an eutectoid invariant between 802 and 955 K, below which it decomposes to face-centered cubic Cu Plus Cu51Zr14-beta-Second, the Cu5Zr8 phase, previously reported as stable, was not observed in a Cu-56.4 at% Zr alloy after holding at 955 and 1036 K for >100 h . This phase, therefore, was not considered to be stable. Based on computational and experimental results, Gibbs free energies were modeled, including the Cu2Zr-sigma, Cu24Zr13-mu and metastable CuZr-(B19' and B33) phases. The associated phase diagrams are presented.
10.1016-j.actamat.2010.01.049	-1		Microstructural evolution associated with the shear banding in nano-scale twin/matrix (T/M) lamellae of a Cu-Al alloy processed by means of dynamic plastic deformation was investigated using transmission electron microscopy (TEM) and high-resolution TEM The development of a shear band was found to be a two-stage process, namely a nucleation stage resulting in a narrow band composed of nano-sized (sub)grams intersecting the T/M lamellae, followed by a thickening stage of the narrow band into adjacent T/M lamellae regions The nucleation stage occurred within a narrow region of an almost constant thickness (100-200 nm thick, referred to as core region) and consisted of three steps (I) initiation of localized deformation (bending, necking, and detwinning) against the T/M lamellae, (2) evolution of a dislocation structure within the detwinned band, and (3) transformation of the detwinned dislocation structure (DDS) into a nano-sized (sub)grain structure (NGS) On the two sides of a core region, two transition layers (TRLs) exist where the T/M lamellae experienced much less shear strain The interface boundaries separating the core region and the TRLs are characterized by very large shear strain gradients accommodated by high density of dislocations Increasing shear strains leads to thickening of shear bands at the expense of the adjoining T/M lamellae, which is composed of thickening of the core region by transforming the TR Ls into the core region with DDS and NOS, analogous to steps (2) and (3) of the nucleation process, and outward movement of the Tins by deforming the adjoining T/M lamellae Grain sizes in the well-developed shear bands are obviously larger than the lamellar thickness of original T/M lamellae (C) 2010 Acta Materialia Inc Published by Elsevier Ltd All rights reserved
10.1016-j.actamat.2010.03.029	13	clusters; atomic; glass; atoms; composition; dynamics; metallic; icosahedral; glasses; simulations; molecular; cu-zr; molecular dynamics; metallic glasses; structural	The paper focuses on the relationship between icosahedral clustering with medium-range order in amorphous metals and local elastic properties. Using a Cu-Zr binary amorphous model constructed by rapid quenching in the framework of molecular dynamics simulations, Voronoi polyhedra analysis shows that the icosahedra are not randomly distributed in space, but form characteristic interpenetrating icosahedral clustering with medium-range order. It is shown that the center atoms of icosahedra within the highly developed interpenetrating icosahedral clusters have higher local elastic moduli than those of independently existing icosahedra and other polyhedra with lower coordination numbers.
10.1016-j.actamat.2010.05.026	-1		(Cu0.5Zr0.5)(100-x)Al-x (x = 5, 6, 8) bulk metallic glasses (BMGs) were deformed in tension. Besides ductility up to 0.5%, the material shows work-hardening behaviour. Both effects are attributed to the deformation-induced precipitation of B2 CuZr nanocrystals and the formation of twins in the nanocrystals larger than 20 nm. The precipitation of the nanocrystals alters the stress field in the matrix and is expected to retard shear band propagation, which in turn allows stresses in the nanocrystals to rise. This stress build-up is more severe in the larger grains and might be responsible for the subsequent twinning. Both deformation-induced nanocrystallization and twinning consume energy and avoid crack formation and with it premature failure.
10.1016-j.actamat.2010.05.046	4	transformation; martensite; martensitic; phase; shape; beta; memory; shape memory; temperature; temperatures; martensitic transformation; gamma; transformation temperatures; effect; thermal	Stress-induced martensitic transformations and twinning processes were studied in thin foils of CuAlNi single crystals strained in situ in a transmission electron microscope. The nucleation and growth of the martensite plates were monitored for three transformation processes known from bulk experiments: (i) the transformation of austenite into 2H martensite at low-stress levels; (ii) the twinning/detwinning processes in 2H martensite; and (iii) the transformation between austenite and 18R martensite at higher stress levels. The morphology of the austenite/martensite habit planes was examined, and the existence of planar interfaces between a single variant of 2H martensite and austenite on the microscopic level was proven.
10.1016-j.actamat.2010.07.038	4	transformation; martensite; martensitic; phase; shape; beta; memory; shape memory; temperature; temperatures; martensitic transformation; gamma; transformation temperatures; effect; thermal	Stress-Induced martensite nucleation and further growing, in Cu-Al-Ni shape memory alloys, have been studied during in situ superelastic tests in the transmission electron microscope Two kinds of martensite, beta(3)' and gamma(3)', are induced and can coexist under stress, both exhibiting in a high density of stacking faults. The interface plane and the orientation relationships between the different variants of such martensites have been determined, and the atomic configurations of the lattices across the interface have been described. Finally, in light of the results, selection rules for the stress-Induced promoted martensites at the nano-scale have been established, being determined by the shear direction and the basal plane of the martensite lattice. (C) 2010 Acta Materialia Inc. Published by Elsevier Ltd All rights reserved
10.1016-j.actamat.2010.09.053	-1		Films of Cu-Ru-Zr and Cu-Zr were deposited on SiO2/Si substrates by magnetron sputtering Samples were subsequently annealed at temperatures of up to 500 degrees C for 1 h and analyzed by four-point probe measurement X-ray diffraction (XRD) transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS) and Auger electron spectroscopy The XRD data suggest that the Cu film has a preferential (1 1 1) crystal orientation According to the TEM results the grain size of the alloy Cu film is smaller than that of a pure Cu film XPS indicates that a ZrOx layer has formed at the Cu alloy/SiO2 interface and that its thickness in the annealed Cu-Ru-Zr/SiO2/Si sample becomes larger due to Ru incorporation After annealing the resistivity values of the annealed Cu alloy films are a little higher than that of annealed pure Cu film These results indicate that Cu-Ru-Zr films are suitable for advanced barrier-free metallization from the view of interfacial stability and low resistivity (C) 2010 Acta Materialia Inc Published by Elsevier Ltd All rights reserved
10.1016-j.actamat.2010.10.039	13	clusters; atomic; glass; atoms; composition; dynamics; metallic; icosahedral; glasses; simulations; molecular; cu-zr; molecular dynamics; metallic glasses; structural	The dynamic wetting of Cu-Ag binary alloys of different concentrations on rigid Ni surfaces is considered via molecular dynamics. The statics of wetting are studied with regard to the alloy concentration. The dynamic data (speed nu, dynamic contact angle theta) are compared to the Molecular-Kinetic model by a fitting procedure. To validate the fittings, the microscopic features of the mechanism are studied. The main parameter of this model (the equilibrium jump frequency K-theta) is calculated independently in the simulation. The two values, fitted and measured, are compatible, which extends the validity of the MKT theory for alloys. We also observe in our simulations Marangoni effects and Ag demixing in the formation of an adsorbed layer. Our results also seem to indicate that there is an optimum Cu-Ag binary alloy concentration for increasing the speed of wetting.
10.1016-j.actamat.2010.11.006	-1		The properties of a composite material are determined not only by the constitutive properties of the matrix and the reinforcement, but also by the type and nature of interfacial bonding between them. For thermo-mechanical applications, the influence of interfaces and interphases is fundamental. In this work, we comprehensively study the copper alloy/carbon fiber composite material interfaces, with and without interphases, in terms of microstructural and chemical properties at the micro- and nanometric scales. These properties are then correlated with the local mechanical properties as determined by nanoindentation, enabling us to establish a direct relationship between the chemistry and mechanical properties at the microscale. In addition to experimental measurements, three-dimensional finite element simulations are performed on the matrix/interphase/reinforcement system, and the results between experiments and simulations show very good agreement, validating our basic hypothesis that the local mechanical properties are determined by the material chemistry.
10.1016-j.actamat.2010.11.048	-1		A nanostructured pure Cu sample consisting of nano-scale twin bundles and nano-sized grains was produced by means of dynamic plastic deformation (DPD) at cryogenic temperature. The apparent activation energy for recrystallization of the nanostructured Cu was determined, being similar to 57 kJ mol(-1). Interfacial diffusion of Zn in the nanostructure was investigated using secondary ion mass spectrometry within the temperature range 358-463 K, in which the volume diffusion is negligible. The measured penetration profiles showed two distinct sections with different slopes, owing to the direct and independent diffusion fluxes along twin boundaries (TB) and grain boundaries (GB). The determined GB diffusivity is similar to 2 orders of magnitude higher than the TB diffusivity. Relative to the diffusivities and free energies of GB and incoherent TB in coarse-grained Cu, both values in the DPD Cu sample are slightly higher at temperatures <373 K, and approach comparable values at higher temperatures.
10.1016-j.actamat.2011.06.013	6	grain; deformation; strain; strength; dislocation; cu-; tensile; size; ecap; grain size; sfe; ductility; hardening; high; stress	Nanostructured Cu-Al alloys with different stacking fault energies (SFEs) corresponding to Al concentrations in a range of 0 4.5 wt% are prepared by means of plastic deformation. Effects of SFE, strain rate and temperature on microstructure characteristics and strength have been systematically investigated in the Cu-Al alloys. It was found that the deformation occurs mainly by twinning at the nanoscale in all samples subjected to dynamic plastic deformation at liquid nitrogen temperature. In the quasi-static compression process at room temperature, dislocation slip dominates the plastic deformation when the SFE is higher than 50 mJ m(-2). With decreasing SFE, twinning becomes the dominant deformation mechanism. A map of deformation modes and corresponding strain-induced microstructures is drawn in the SFE-processing parameters space for the Cu-Al alloys. In both sets of deformation mode, twinning is obviously enhanced by decreasing the SFE, resulting in smaller twin/matrix (T/M) lamella thickness and grain sizes. Consequently, an obvious strength elevation is induced by the size effects of grains and T/M lamellae with lower SFEs.
10.1016-j.actamat.2011.09.058	-1		Disks of a eutectic Cu-Ag alloy were processed by high-pressure torsion (HPT) up to 20 revolutions to reveal the microstructural evolution and mechanical properties. Both the Cu and Ag phases were thinned continuously with increasing numbers of revolutions. After 20 revolutions, the alternating Cu and Ag phases were significantly refined and became fibrous with dimensions as thin as 5 nm. The strain hardening behavior of the Cu-Ag alloy was characterized after different numbers of HPT revolutions, and a saturation microhardness was attained. It is shown that the tensile fracture mode changed from necking to fully brittle shearing with increasing numbers of revolutions, and some shear offsets with sizes of similar to 5-20 mu m were observed on the fracture surfaces. Based on the abnormal saturation microhardness value of the eutectic alloy, the strengthening mechanisms of various Cu-Ag alloys are discussed.
10.1016-j.actamat.2011.11.013	-1		A combination of electron microscopy, focused ion beam and conductive atomic force microscopy techniques have been used to study the microstructure, oxide scale development, and electrical behavior of a Cu-9 at% La alloy. The as-cast alloy exhibits a eutectic microstructure comprising 30 vol.% Cu rods in a Cu6La matrix. The eutectic colonies exhibit a singular orientation relationship with [0 1 0] Cu6La parallel to < 0 1 1 > Cu along the rod axis, and it is shown that this corresponds to lattice matching of the two phases along this direction (similar to 0.02% misfit). Oxidation of the alloy at 100 degrees C to accelerate formation of a native oxide scale led to the development of a Cu2O layer less than 25 nm thick on the Cu rods and a La-doped Cu2O scale up to I am thick on the Cu6La matrix. The La-doped regions of the scale are more conductive despite being much thicker, which is consistent with previous contact resistance data obtained for this alloy. The mechanisms responsible for the formation of this non-equilibrium oxide scale structure and for the enhanced electrical conductivity of the La-doped regions are discussed.
10.1016-j.actamat.2012.03.030	-1		Directional solidification experiments on hypoperitectic Cu-Sn alloys have been performed at very low velocity in a high thermal gradient to ensure planar front growth of both phases. The diameter of the sample has been reduced to 500 mu m to strongly reduce convection. Lamellar and fibrous peritectic cooperative growth of the primary alpha- and peritectic beta-phases has been observed on length spanning several millimeters. For the first time in a high solidification interval peritectic alloy, a quenched interface of both phases in contact with the liquid has been obtained. An unexpectedly high volume fraction of the primary phase, which furthermore fluctuates over time, has been observed. This is attributed to the transient state of the (alpha + beta) growth front to a steady state and the associated evolution of the large diffusion layer ahead of the solid-liquid interface.
10.1016-j.actamat.2012.04.021	4	transformation; martensite; martensitic; phase; shape; beta; memory; shape memory; temperature; temperatures; martensitic transformation; gamma; transformation temperatures; effect; thermal	Superelastic nanocompression tests are performed on different micropillars milled by focused ion beam from [001]-oriented single crystals of Cu-Al-Ni shape memory alloys. Over hundreds of cycles such micropillars exhibit reproducible superelastic behavior with complete recovery at stresses around 300 MPa and stress-induced transformation strains above 5%. Upon cycling, the critical stress to induce the transformation decreases, and the transformation strain increases, both signatures of a training effect which is analyzed here in terms of the microscopic mechanisms controlling the nucleation, growth and recovery of the martensite plates. The mechanical hysteresis is characterized through the energy dissipated during closed superelastic cycles, and its evolution during cycling is discussed. The superelastic cycling of the micropillars is also found to depend on the strain rate. The highest strain rate studied here, 10(-1) s(-1), is found to impinge upon the nucleation and growth kinetics of gamma(')(3) and beta(')(3) martensites, with the result that the mechanical hysteresis and transformation strain are reduced. Finally, specific cycling tests have been conducted at increasing maximum loads to analyze the limit for plastic deformation of the micropillar, which happens between 500 and 700 MPa.
10.1016-j.actamat.2012.04.022	-1		The plastic flow field produced by machining is utilized to access a range of deformation parameters in pure copper: strains of 1-7, strain rates of 1-1000 s(-1) and temperatures as low as 77 K. The strength and stability of the severe plastic deformation microstructures including cellular, elongated, equiaxed and twinned types are characterized. Unique combinations of strengthening and stability are identified in the case of heavily twinned microstructures. These observations offer insights for improving the stability of both single-phase and multicomponent ultrafine-grained alloys.
10.1016-j.actamat.2012.09.036	-1		A bulk nanostructured alloy with the nominal composition Cu-30Zn-0.8Al wt% (commercial designation brass 260) was fabricated by cryomilling of brass powders and subsequent spark plasma sintering (SPS) of the cryomilled powders, yielding a compressive yield strength of 950 MPa, which is significantly higher than the yield strength of commercial brass 260 alloys (similar to 200-400 MPa). Transmission electron microscopy investigations revealed that cryomilling results in an average grain diameter of 26 nm and a high density of deformation twins. Nearly fully dense bulk samples were obtained after SPS of cryomilled powders, with average grain diameter 110 nm. After SPS, 10 vol.% of twins is retained with average twin thickness 30 nm. Three-dimensional atom-probe tomography studies demonstrate that the distribution of Al is highly inhomogeneous in the sintered bulk samples, and Al-containing precipitates including Al(Cu,Zn)-O-N, Al-O-N and Al-N are distributed in the matrix. The precipitates have an average diameter of 1.7 nm and a volume fraction of 0.39%. Quantitative calculations were performed for different strengthening contributions in the sintered bulk samples, including grain boundary, twin boundary, precipitate, dislocation and solid-solution strengthening. Results from the analyses demonstrate that precipitate and grain boundary strengthening are the dominant strengthening mechanisms, and the calculated overall yield strength is in reasonable agreement with the experimentally determined compressive yield strength .
10.1016-j.actamat.2012.09.053	6	grain; deformation; strain; strength; dislocation; cu-; tensile; size; ecap; grain size; sfe; ductility; hardening; high; stress	Ultrafine-grained materials produced by different severe plastic deformation methods show very high strengths but their tensile ductility is often very low. In the present work, we demonstrate an approach for retaining high strength while recovering ductility in a Cu-3 at% Ag alloy through cold rolling and short-time annealing. X-ray line profile analysis of cold-rolled and annealed samples reveals the development of a heterogeneous solute atom distribution due to the dissolution of nanosized Ag particles in some regions of the matrix. In regions with higher solute (Ag) content, the high dislocation density present following rolling is stabilized, while in other volumes the dislocation density is decreased. High-resolution scanning electron microscopy confirms the presence of regions of varying Ag content in the matrix. Microstructure analysis of the rolled and annealed samples revealed bimodal grain size, dislocation density and solute Ag distributions as well as nanosized Ag precipitation. The as-rolled samples exhibit high tensile strengths of similar to 600-700 MPa with negligible uniform elongation (similar to 1%). After short-time annealing the strength decreases only slightly to similar to 550-620 MPa with significant improvement in uniform elongation (from 1 to 10%); this is mainly attributed to the bimodal microstructure.
10.1016-j.actamat.2012.10.031	-1		High-resolution transmission electron microscopy and first-principles energy calculations reveal that, upon formation, the hardening precipitates in Cu-Ni-Si alloys are unchanged delta-Ni2Si nanocrystals. However, their crystallographic and morphological features evolve during the precipitation process. It is shown that, in terms of crystallographic orientation relationships, there are basically two types of delta-Ni2Si precipitates in the alloys, referred to as delta(1)-Ni2Si and delta(2)-Ni2Si respectively. In the early stages of aging (including peak aging), the precipitates are small and belong to the delta(1) type, with the following orientation relationship with the Cu matrix: [0 1 0](delta)parallel to[1 1 0](Cu) and (0 0 1)(delta)parallel to(0 0 1)(Cu). In the late stages, the precipitates are clearly larger and become the delta(2) type, with the orientation relationship: [0 1 0](delta)parallel to[1 1 0](Cu) and approximately (3 0 1)(delta)parallel to(1 (1) over tilde 1)(Cu). Governed by the minimization of its overall energy, a developing delta precipitate has to evolve from an almond-like delta(1) particle with a low-index coherent habit plane to a French baguette bread-slice-shaped delta(2) particle that has a high-index broad interface. This evolution is found to be in excellent agreement with predictions provided by the invariant line theory. Intermediate stages exist for a particle to accomplish such an evolution, leading to many different crystallographic and morphological appearances of these delta-Ni2Si particles being observed in the alloys.
10.1016-j.actamat.2012.11.031	6	grain; deformation; strain; strength; dislocation; cu-; tensile; size; ecap; grain size; sfe; ductility; hardening; high; stress	Pure Cu, Cu-0.41 at% Si and Cu-1.64 at% Si alloys were severely deformed by an accumulative roll bonding (ARB) method and the resultant microstructure was observed using high-voltage electron microscopy and scanning transmission electron microscopy. Although the mean boundary separation along the ARB normal direction was dependent on the Si concentration, the dislocation density within grains and cells depended very weakly on the Si concentration and stayed around 5 x 10(14) m(-2). Uniaxial tensile tests were also performed at room temperature. The contribution of dislocations and grain boundaries to the strength was estimated using two models: one based on the Taylor-type and Hall-Petch-type strengthening mechanisms, the other based on thermally activated dislocation depinning from grain boundaries. Both model provide reasonable values for yield strength compared with 0.2% proof stress values, and therefore the grain size region used in this study may be the transition region between these two models.
10.1016-j.actamat.2012.12.020	7	irradiation; shear; grain; ta; deformation; size; radiation; voids; nanocrystalline; simulations; similar; void; temperature; irradiated; boundaries	A novel approach towards coarsening resistance in the precipitate-strengthened Cu-based alloys is proposed, taking advantage of selective precipitation during low-temperature ion irradiation. In the case of Cu-Nb-W, W precipitates during room temperature irradiation, forming highly ramified clusters. During subsequent thermal annealing of alloys with composition close to Cu90Nb9W1, the more mobile Nb atoms precipitate out on the W clusters, creating a core-shell structure and adopting the Bain orientation relationship within the Cu matrix. This structure is extremely resistant to coarsening. Annealing at 650 degrees C for 1 h results in a precipitates size <4 am in diameter, and annealing for an additional 9 h causes no additional growth, even though Nb is highly mobile at this temperature and would coarsen in the absence of W. We attribute the remarkable stability of this precipitate structure to the strong immiscibility of W in Cu and to the highly ramified precipitate structure that W acquires during low-temperature irradiation.
10.1016-j.actamat.2012.12.022	13	clusters; atomic; glass; atoms; composition; dynamics; metallic; icosahedral; glasses; simulations; molecular; cu-zr; molecular dynamics; metallic glasses; structural	We present a novel experimental technique for studying the structure of metallic glasses (specifically Cu-Zr) through a proxy system of charged colloidal particles. A dense suspension of two types of colloidal particles that match the relative size ratio and approximate the attractive interaction of Cu and Zr atoms is created. Confocal microscopy images are analyzed to find the location of tens of thousands of particles at each composition studied. The particle locations are used to determine the packing fraction, partial radial distribution functions and partial coordination numbers of each component as well as the shape of clusters (central atom and first shell neighbors) that form. These results are compared to experimental and simulation literature on Cu-Zr systems, with good agreement found among all structural properties.
10.1016-j.actamat.2013.01.021	6	grain; deformation; strain; strength; dislocation; cu-; tensile; size; ecap; grain size; sfe; ductility; hardening; high; stress	The mechanical response of a copper-2 wt% beryllium alloy in either a solution treated or aged condition has been investigated within the shock loading regime. In terms of Hugoniot Elastic Limit, shear strength and spall (dynamic tensile) strength, the material in the aged condition has been observed to be significantly stronger than when in the solution treated state. Whilst these trends are the same as when tested under quasi-static conditions, the level of strengthening due to shock loading is less than during quasi-static loading. It is believed that the distribution of non-shearable particles within the microstructure (caused by aging) restrict the ability of the material to deform via dislocation motion and generation, which in turn reduces strain-rate sensitivity. Thus the relative differences in strength between aged and solution treated materials will be less under shock loading conditions compared to quasi-static conditions. In contrast, strong similarities between the shear strengths of the solution treated material and pure copper were noted., It has been suggested that twinning in the alloy may be responsible (due to the small contribution of twins to shock induced strengthening), although comparison of partial dislocation separation between the two materials suggest otherwise. Crown Copyright
10.1016-j.actamat.2013.04.029	-1		The co-deformation and shear localization in heterophase alloys is studied using two-dimensional crystal plasticity finite element simulations on plane strain compressed Cu-Ag and Cu-Nb metal matrix composites. The aim is to study the fundamentals of micromechanics, co-deformation and shear banding in materials with heterophase interfaces. It is observed that, depending on the initial orientations of the crystals, co-deformation of the constituent heterophases often proceeds via collective mechanisms, i.e. by pronounced shear banding triggered by stress concentration at the interfaces. This phenomenon leads to highly localized strains within the bands, exceeding the average strain in part by two orders of magnitude. Shear band development is related to the inherent mechanical properties of each crystal and also to the properties of the abutting crystals. The predicted topology and nature of the cross-phase shear bands, i.e. the extreme local strains, significant bending of the interface regions, and sharp strain localization that propagates across the interfaces, agree well with experimental observations in cold-rolled composites. The simulations reveal that cross-phase shear banding leads to large and highly localized values of stress and strain at heterophase interfaces. Such information is essential for a better understanding of the micromechanical boundary conditions inside co-deformed composites and the associated shear-induced chemical mixing.
10.1016-j.actamat.2013.06.032	6	grain; deformation; strain; strength; dislocation; cu-; tensile; size; ecap; grain size; sfe; ductility; hardening; high; stress	In this study, fatigue behaviors of pure copper with different grain sizes are investigated under cyclic tension-compression and torsion loadings. The fatigue responses of ultrafine-grained (UFG) Cu subjected to equal-channel angular pressing (ECAP) are compared and contrasted with those of coarse-grained (CG) and cold-rolled (CR) Cu. It is found from the S-N curves under the two different loading modes that, in the high-cycle fatigue (HCF) range, the fatigue strength of Cu does not exhibit strong dependence on the grain size under cyclic tension-compression loading, whereas the fatigue strength of UFG Cu is greatly improved over those of CG and CR Cu under cyclic torsion loading. Under cyclic tension-compression loading, the fatigue strength exponent decreases with the refinement of grain size; however, under cyclic torsion loading, with decreasing grain size, its fatigue strength exponent shows the opposite trend and goes up. To explain the phenomena above, the relations between the fatigue strength exponent and fatigue strength coefficient are discussed. Based on the two main stages of fatigue failure (crack initiation and propagation stages), the influences of grain size on fatigue strength exponent and fatigue strength in the HCF range under the two fatigue modes are comprehensively analyzed.
10.1016-j.actamat.2013.07.044	-1		Minor elements, when added to binary amorphous alloys in small percentages, can often lead to significant improvements in both the plasticity and glass-forming ability (GFA) of the alloys. Considering that plasticity and GFA are two contrasting properties dependent on short-range orders (SROs) of differing degrees, this experimental observation at first seems paradoxical when considered from an SRO viewpoint. In this study, comparative studies on amorphous alloys Cu50Zr50 and Cu47.5Zr47.5Al5 were performed using experiments and simulations to elucidate how these two apparently mutually exclusive properties can be realized at the same time. Using molecular dynamics simulations, we resolved the local structures of Cu50Zr50 and Cu47.5Zr47.5Al5 in terms of icosahedral medium-range orders. In addition, the role of the minor element (Al) on the formation of the icosahedra and their medium-range structures during cooling, as well as their disordering behavior during subsequent plastic relaxation, was clarified.
10.1016-j.actamat.2013.08.047	-1		The results of high energy X-ray scattering studies of equilibrium and supercooled Cu100-xZrx (x = 46 and 54) and CuxHf100-x (x = 55 and 60.8) liquids and the corresponding glasses are presented. The liquid data were obtained in a containerless environment using the beamline electrostatic levitation (BESL) technique. The total structure factor and total pair correlation functions were measured as a function of temperature for the liquids, and for the glasses at room temperature. A developing asymmetry in the peak of the first coordination shell in the total pair correlation function suggests chemical ordering in the liquids with cooling. This asymmetry takes the form of two prominent peaks, suggesting two prominent ordering length scales. When the magnitudes of these peaks are extrapolated to the glass transition temperature a discontinuity is observed, indicating that an abrupt increase in the magnitude is required to match the observed peak heights in the glass. This suggests that the structure of the supercooled liquid orders more rapidly near the glass transition temperature, a conclusion that is supported by molecular dynamics simulations. This observed structural evolution of the liquid indicates that the concept of fragility, typically defined from the behavior of viscosity with temperature, has a measurable structural signature as well, which can be observed in X-ray diffraction studies.
10.1016-j.actamat.2013.08.057	-1		A nanocrystalline face-centered cubic (fcc) solid solution of 6% Fe in Cu was prepared by high-energy ball milling, and annealed at temperatures from 200 to 360 degrees C to induce chemical unmixing. The chemical state of the material was characterized by three-dimensional atom probe microscopy, Mossbauer spectrometry and X-ray powder diffractometry. The unmixing was heterogeneous, with iron atoms forming iron-rich zones that thicken with further annealing. The phonon partial density of states (pDOS) of Fe-57 was measured by nuclear resonant inelastic X-ray scattering, showing the pDOS of the as-prepared material to be that of an fcc crystal. The features of this pDOS became broader in the early stages of unmixing, but only small changes in average phonon frequencies occurred until the body-centered cubic (bcc) phase began to form. The vibrational entropy calculated from the pDOS underwent little change during the early stage of annealing, but decreased rapidly when the bcc phase formed in the material.
10.1016-j.actamat.2013.10.009	7	irradiation; shear; grain; ta; deformation; size; radiation; voids; nanocrystalline; simulations; similar; void; temperature; irradiated; boundaries	Severe plastic deformation (SPD) of Cu, Ag and Nb ternary alloys with average Nb concentrations of 5, 10 and 15 at% and an Ag concentration of 10 at% was studied using high resolution scanning electron microscopy, atom probe tomography and X-ray diffraction. Ball-milled powders were compacted, annealed at 600 or 950 degrees C and subsequently strained by high pressure torsion at room temperature. Ag redistributed homogeneously in the Cu matrix during SPD, but the Nb solubility increased by less than 1%. The Nb precipitates, moreover, self-organized into a patterned microstructure, whereby their sizes all fell within a narrow distribution, centered on similar to 20 nm. This size was independent of the initial microstructure for a given alloy and insensitive to the Nb concentration. The size was also insensitive to the method of shearing. Since Nb diffusion is negligible in Cu at room temperature, these results establish that SPD alone can induce compositional patterning in highly immiscible alloys. We discuss the mechanisms responsible for this behavior.
10.1016-j.actamat.2013.11.018	7	irradiation; shear; grain; ta; deformation; size; radiation; voids; nanocrystalline; simulations; similar; void; temperature; irradiated; boundaries	Using microcompression methodology, various plastic deformation characteristics, namely the strength, strain-rate sensitivity (SRS) and activation volume, of < 1 0 0 >-single-crystalline (SC) Cu micropillars and nanostructured multicrystalline (MC) Cu micropillars with several grains were systematically investigated at different strain rates for a wide range of external sample sizes ranging from 300 to 2000 urn. The results revealed that the paradigm of smaller is stronger for small-scaled SC pillars holds true in nanostructured MC Cu micropillars above the strongest external size; however, below this size, a decrease in the external size triggers the reverse size effect, i.e. smaller is weaker. The appropriate introduction of grain boundaries into SC pillars can markedly improve the smoothness of their plastic flow and significantly enhance their SRS. Additionally, we demonstrated that the SRS of MC Cu pillars increases with decreasing size up to a certain limit and then decreases with a further decrease in the external sample size; thus, a maximum SRS emerges. A phenomenological model was proposed to rationalize the scaling behavior of the activation volume with the external sample size and to highlight the effect of the internal feature size on the rate-limiting behavior of conventional bulk nanostructured metals (Cu).
10.1016-j.actamat.2013.11.027	-1		Within the context of rapid solidification, a melt-fluxing technique has been employed to study the microstructural development and the velocity undercooling relationship of a Cu-8.9 wt% Ni alloy. A number of microstructural transitions have been observed up to undercoolings of 235 K. At the lowest undercoolings, single grain, < 100 > type dendritic structures are observed, which give way to a recrystallized grain structure as undercooling is increased. At intermediate undercoolings, twinned dendritic samples exhibiting features of mixed orientation are reported. Within this range, the dominant < 100 > character is evidenced by eightfold growth at low undercooling whilst the < 111 > character begins to dominate at high undercooling, accompanied by a switch to sixfold growth . It is believed that this range of undercooling represents an extended transition between fully < 100 > oriented growth at low undercooling and fully < 111 > oriented growth at high undercooling. It is suggested that an observed positive break in the velocity undercooling relationship at high undercooling is therefore coincident with the transition to fully < 111 > growth, though this could not be confirmed microstructurally. The existence of competing anisotropies in the growth directions at intermediate undercoolings appears to be giving rise to a novel form of the dendritic seaweed structure, characterized by its containment within a diverging split primary dendrite branch . In addition, at the highest undercoolings achieved, an equiaxed-to-elongated grain structure is observed, in which an underlying dendritic seaweed substructure exists. We suggest that this structure may be an intermediate in the spontaneous grain refinement phenomenon, in which case dendritic seaweed appears to play some part.
10.1016-j.actamat.2014.02.003	-1		In the Cu-Cr system, the formation of supersaturated solid solutions can be obtained by severe plastic deformation. Energy-dispersive synchrotron diffraction measurements on as-deformed Cu-Cr samples as a function of the applied strain during deformation confirm the formation of supersaturated solid solutions in this usually immiscible system. Due to evaluation of the diffraction data by a newly developed energy-dispersive Rietveld program, lattice parameter and microstructural parameters such as domain size and microstrain are determined for as-deformed as well as annealed samples. The obtained information is used to deepen the understanding of the microstructural evolution and the formation of supersaturated solid solutions during severe plastic deformation. Complimentary transmission electron microscopy investigations are furthermore performed to characterize the evolving microstructure in detail. After annealing at elevated temperatures, the formed solid solutions decompose. Compared to the as-deformed state, an enhanced hardness combined with a high thermal stability is observed. Possible mechanisms for the enhanced hardness are discussed.
10.1016-j.actamat.2014.03.029	-1		Experimentally and computationally, the structure of Pt-Cu at 1:3 stoichiometry has a convoluted history. The L1(3) structure has been predicted to occur in binary alloy systems, but has not been linked to experimental observations. Using a combination of electron diffraction, synchrotron X-ray powder diffraction, and Monte Carlo simulations, we demonstrate that it is present in the Cu-Pt system at 1:3 stoichiometry. We also find that the 4-atom, fcc superstructure L1(3) is equivalent to the large 32-atom orthorhombic superstructure reported in older literature, resolving much of the confusion surrounding this composition. Quantitative Rietveld analysis of the X-ray data and qualitative trends in the electron-diffraction patterns reveal that the secondary X-1(+) (a, 0, 0) order parameter of the L1(3) phase is unexpectedly weak relative to the primary L-1(+) (a, a, 0, 0) order parameter, resulting in a partially-ordered L1(3) ordering, which we conclude to be the result of kinetic limitations. Monte Carlo simulations confirm the formation of a large cubic superstructure at high temperatures, and its eventual transformation to the L1(3) structure at lower temperature, but also provide evidence of other transitional orderings.
10.1016-j.actamat.2014.03.040	-1		Bulk nanolayered Cu/Nb composites fabricated by accumulative roll bonding (ARB), leading to a nominal layer thickness of 18 nm, were subjected to large shear deformation by high-pressure torsion at room temperature. The evolution of the microstructure was characterized using X-ray diffraction, transmission electron microscopy and atom probe tomography. At shear strains of the crystallographic texture started to change from the one stabilized by ARB, with a Kurdjumov-Sachs orientation relationship and a dominant {1 1 2}(Cu)parallel to{1 1 2}(Nb) interface plane, toward textures unlike the shear texture of monolithic Cu and Nb. At larger strains, exceeding 10, the initial layered structure was progressively replaced by a three-dimensional Cu-Nb nanocomposite. This structure remained stable with respect to grain size, morphology and global texture from strains of similar to 290 to the largest ones used in this study, 5900. The three-dimensional self-organized nanocomposites comprised biconnected Cu-rich and Nb-rich regions, with a remarkably small coexistence length scale, similar to 10 nm. The results are discussed in the context of the effect of severe plastic deformation and strain path on microstructure and texture stability in highly immiscible alloy systems.
10.1016-j.actamat.2014.03.055	7	irradiation; shear; grain; ta; deformation; size; radiation; voids; nanocrystalline; simulations; similar; void; temperature; irradiated; boundaries	Molecular dynamics is used to investigate in-plane simple shear deformation of three Cu-Nb interfaces with either Kurdjumov-Sachs (KS) or Nishiyama-Wassermann (NW) orientation relationships (ORs). Regardless of the shear direction, both the NW interface and the KS interface with a {1 1 1}fcc parallel to{1 1 0}bcc habit plane consistently deform via pure interface sliding and are highly stable against the shear deformation. In contrast, the KS interface with a {1 1 2}fcc parallel to {1 1 2}bcc habit plane exhibits at small strain various deformation mechanisms along different shear directions. Dislocation glide inside the Cu phase results in a change from the original OR. At large strains, additional strain is accommodated almost entirely by localized shearing at interfacial amorphous layers, which grow as the square root of strain, irrespective of shear direction, phase layer thickness or habit plane. With the onset of such shear localization, a new OR becomes stabilized, although it varies with shear direction. The findings in this study are discussed with respect to structural evolution, amorphization, forced mixing, shear strength and experimental observations.
10.1016-j.actamat.2014.03.060	7	irradiation; shear; grain; ta; deformation; size; radiation; voids; nanocrystalline; simulations; similar; void; temperature; irradiated; boundaries	Sliding friction of metallic materials results in severe plastic deformation of the contacting surfaces. While plastic deformation is generally considered detrimental, as it leads to localized material failure and wear, in some cases it can trigger the formation of self-organized microstructures with the potential for improved wear resistance. We report here on a novel, self-adapting mechanism in a Cu90Ag10 two-phase alloy that relies on the spontaneous formation of chemically nanolayered structures during sliding wear. For sufficiently large initial Ag precipitate sizes, the nanolayered structures remain stable up to the sliding surface, leading to a reduction in wear rate. Similar chemically nanolayered structures are observed in Cu90Ag10 alloys deformed by high-pressure torsion, enabling controlled investigation of this process. The results of these studies suggest a novel approach, through self-organization, for designing metallic alloys that can achieve low wear rates.
10.1016-j.actamat.2014.04.053	6	grain; deformation; strain; strength; dislocation; cu-; tensile; size; ecap; grain size; sfe; ductility; hardening; high; stress	Cyclic deformation responses of ultrafine-grained (UFG) Cu and nanocrystalline (NC) Cu Al alloys produced by equal channel angular pressing were investigated systematically by applying low-cycle fatigue (LCF) and high-cycle fatigue (HCF) tests. Based on the dependence of the fatigue life (N-f) on the total strain amplitude (Delta epsilon(t)/2) and stress amplitude (Delta sigma/2) in comparison with that of UFG Cu, the LCF life and HCF strength, especially fatigue endurance limits, of NC Cu Al alloys, were enhanced strikingly at the same time as their stacking fault energies (SFE) decreased. These upgraded fatigue performances with lowering of the SFE in NC Cu Al alloys can be attributed not only to the simultaneous increase in their monotonic strength and ductility on the macroscale, but also to the crucially decreased cyclic softening behavior on the microscale. It was found that substantial grain growth and large-scale shear bands, both of which are essential ingredients, resulting in significant cyclic softening and then deterioration in the LCF life of UFG and NC materials, were reduced advantageously on decreasing the SFE in NC Cu-Al alloys. Moreover, the dominant fatigue damage micro-mechanism was also transformed inherently from extensive grain boundary (GB) migration in UFG Cu to other local GB activities such as atom shuffling or GB sliding/rotation in NC Cu Al alloy with low SFE.
10.1016-j.actamat.2014.07.010	-1		A novel approach towards the design of coarsening-resistant nanoprecipitates in structural alloys was investigated by kinetic Monte Carlo (KMC) simulation. The approach is motivated by recent experimental results in Cu-Nb-W alloys showing that room temperature ion irradiation resulted in W nanoprecipitation, leading to exceptional stability of W-rich-core/Nb-rich-shell nanoprecipitates formed following thermal annealing (Zhang et al, 2013 [11]). Here, image simulations of atomically resolved scanning transmission electron microscopy are performed to establish that these W nanoprecipitates are highly ramified. Thermal precipitate coarsening in an A-B-C ternary alloy similar to Cu-Nb-W is then studied by KMC simulations, where the highly immiscible and refractory C solute atoms are initially distributed into fractal nanoprecipitates, or cores, which become coated by a shell of B atoms during elevated temperature annealing. Compared with nanoprecipitates generated by compact C cores, the ramified nanoprecipitates result in exceptionally high trapping efficiency of B solute atoms during thermal coarsening, and the efficiency increases with the cluster size. The KMC results are analyzed and rationalized by noting that, owing to the Gibbs Thomson effect, when the curvatures of the shell of the precipitates are zero or negative, the microstructure is coarsening-resistant. Such morphology can be realized by facets, or by dynamic balance within positive, negative and zero curvatures.
10.1016-j.actamat.2014.07.027	-1		Introducing a soft crystalline phase into an amorphous alloy can promote the compound's ductility. Here we synthesized multilayered nanolaminates consisting of alternating amorphous Cu54Zr46 and nanocrystalline Cu layers. The Cu layer thickness was systematically varied in different samples. Mechanical loading was imposed by nanoindentation and micropillar compression. Increasing the Cu layer thickness from 10 to 100 am led to a transition from sharp, cross-phase shear banding to gradual bending and co-deformation of the two layer types (amorphous/nanocrystalline). Specimens with a sequence of 100 nm amorphous Cu54Zr46 and 50 nm Cu layers show a compressive flow stress of 2.57 +/- 0.21 GPa, matching the strength of pure CuZr metallic glass, hence exceeding the linear rule of mixtures. In pillar compression, 40% strain without fracture was achieved by the suppression of percolative shear band propagation. The results show that inserting a ductile nanocrystalline phase into a metallic glass prevents catastrophic shear banding. The mechanical response of such nanolaminates can be tuned by adjusting the layer thickness.
10.1016-j.actamat.2014.10.013	-1		Metastable binary Cu-Cr alloys with nominal film thicknesses of 300 nm and chemical compositions in the range of 4-93 at% Cr were synthesized via co-evaporation using molecular beam epitaxy. All films were grown onto Si (100) substrates at deposition rates of similar to 0.05 nm s(-1). The film microstructures were studied by using transmission electron microscopy and X-ray diffraction. The mechanical properties were investigated by the nanoindentation technique. Depending on the chemical composition, three types of thin film microstructures are observed, which all exhibit tensile residual stresses. For a Cr concentration of 4 at% a single-phase face-centered cubic (fcc) film was formed, whereas single-phase body-centered cubic (bcc) films were observed for Cr concentrations >= 33 at%. In the case of a Cu85Cr15 film, a two-phase fcc and bcc structure is formed. An increase of the atomic fraction of Cr induces a significant refinement of grain sizes, from similar to 100 nm for a Cu96Cr4 alloy to similar to 30 nm in the case of a Cu20Cr80 alloy. Consequently, the hardness of the alloy films increased from 5.5 to 11.8 GPa. In addition, the formation of supersaturated solid solutions of Cr in single-phase fcc Cu films and Cu in single-phase bcc films was observed. Predictions of existing models of solid solution and grain boundary strengthening were evaluated and correlated with the mechanical properties of the films with respect to film compositions and grain sizes.
10.1016-j.actamat.2015.01.073	-1		In metals and alloys, phase separation takes place either by nucleation and growth or by spinodal decomposition. Here, transmission electron microscopy (TEM) and atom probe tomography (APT) are combined in an effort to study phase separation in an immiscible Cu-34 at% Ta thin film alloy on a nanometer scale. Upon annealing at 400-600 degrees C the initially X-ray amorphous metastable alloy phase separates and crystallizes into a Cu-rich phase with fcc structure and a Ta-rich phase with beta-Ta structure. While the fcc phase crystallizes already upon 10 min annealing at 400 degrees C, first indications of a crystalline beta-Ta phase are observed after 30 min annealing at 400 degrees C, but this phase does not become fully crystalline at temperatures below 600 degrees C. Proximity histograms of the APT data show that phase separation is taking place predominantly by diffusion of Cu, which is in accordance with the known relative diffusivities of the materials. An increase in the amplitude of the composition fluctuation and a decrease in the width of the interface between Cu-rich and Ta-rich regions are observed in the proximity histograms as phase separation progresses. These results suggest spinodal decomposition as the mechanism of phase separation.
10.1016-j.actamat.2015.05.053	-1		The thermal decomposition behaviour, the microstructural evolution and its influence on the mechanical properties of a supersaturated Cu-Co solid solution with similar to 100 nm average grain size prepared by severe plastic deformation is investigated under non-isothermal and isothermal annealing conditions. Pure fine-grained Cu and Co exhibit substantial grain growth upon annealing, whereas the Cu-Co alloy is thermally stable at the same annealing temperatures. The annealed microstructures are studied by independent characterisation methods, including scanning electron microscopy, electron energy loss spectroscopy and atom probe tomography. The phase separation process in the Cu-Co alloy proceeds by the same mechanism, but on different length scales: a fine scaled spinodal-type decomposition is observed in the grain interior, simultaneously Co and Cu regions with a larger scale are formed near the grain boundary regions. Subsequent grain growth at higher annealing temperatures results in a microstructure consisting of the pure equilibrium phases. Such mechanisms can be used to tailor nano structures.
10.1016-j.actamat.2015.07.050	-1		W-Cu alloys are typically used for heat sinks, radiation shielding or high performance contact materials. Their immiscibility leads to interpenetrating structures, with typically smallest microstructural length scales on the order of several micrometres. This work focusses on tuning this length scale from the atomic level to the nanometre and submicron range. This is made possible by exploiting the two constituents' immiscibility in thermodynamic equilibrium as well as the lack of Cu segregation to W grain-boundaries, thus allowing for the growth of the two phases. The system is studied in the complete concentration range and microstructure is related to both mechanical and electronic properties.
10.1016-j.actamat.2015.08.016	-1		The mechanical behavior of Cu-Cr nanolayered films and an alloy film of nominal composition Cu20Cr80 at% was studied by microcompression testing at temperatures from 25 degrees C to 300 degrees C. Comparing nanolayered films, plastic deformation and failure occurred at consistently higher stress levels in the film with the smaller layer thicknesses. Plasticity in the nanolayered films always initiated in the softer Cu layers followed by a finite strain-hardening response in the stress strain curves. Failure indicated by a strain-softening response following the higher peak strength due to shearing and tearing at columnar boundaries of Cr was observed in the nanolayered films at 25 degrees C and 100 degrees C. A transition from shearing and crack formation across the Cu-Cr interfaces leading to anomalous grain growth or beading of the nanocrystalline Cu layers was observed at elevated temperatures of 200 degrees C and 300 degrees C. On the other hand, the Cu20Cr80 at% alloy film exhibited failure by columnar buckling consistently at elevated temperatures, but shearing promoted by buckling at the highest strengths among the films at ambient temperature.
10.1016-j.actamat.2015.09.015	7	irradiation; shear; grain; ta; deformation; size; radiation; voids; nanocrystalline; simulations; similar; void; temperature; irradiated; boundaries	Thermal spikes in irradiated amorphous metal alloys emit stress pulses of sufficient intensity to trigger plastic deformation in adjacent unmelted material. This localized plasticity may lead to macro-scale anisotropic shape changes in metallic glasses under neutron or ion irradiation, even in the absence of external loading. We formulate a micromechanical model that connects thermal spike-induced plasticity (TSIP) to bulk properties of amorphous metal alloys. This model gives rise to a figure of merit (FOM) for ranking the susceptibility of metallic glasses to TSIP without recourse to further experiments or simulations. We validate the FOM against molecular dynamics simulations of TSIP in amorphous Cu-Nb alloys.
10.1016-j.actamat.2016.04.004	1	shape; memory; shape memory; damping; martensite; martensitic; damping capacity; transformation; capacity; strain; superelasticity; temperature; cu-al-mn; shape memory effect; effect	It is generally believed that an up/step-quenching treatment can suppress the deterioration of shape memory effect (SME) due to the martensitic stabilization. However, recent studies have indicated that the SME in an up-quenched ductile Cu-Al-Mn alloy dropped drastically as lowering the recovery heating rate. To understand whether the above strong heating rate-dependent deterioration in the SME can be ascribed to the martensitic stabilization, we carefully investigated the microstructural differences in an up-quenched Cu-17.0Al-10.5Mn (at%) alloy after deformation and then heating at different rates. The effect of up-quenching time on the SME deterioration induced by lower heating rates was also studied. The results showed that the martensitic stabilization is responsible for strong heating rate dependent deterioration in the SME in the up-quenched Cu-Al-Mn alloy, and whether a certain up quenching treatment can suppress its occurrence is strongly dependent on the recovery heating rate. Available data clearly showed that this dependence also exists in other up/step-quenched Cu-based alloys. The migration, cluster and even collapse of thermodynamically non-equilibrium quenched-in vacancies at the martensite interfaces result in this dependence. The martensite interfaces pinned by the collapsed vacancies cannot be de-pinned through thermal activation.
10.1016-j.actamat.2016.06.010	-1		In this study, dual phase Cu-Co composites with a total immiscibility in the solid state and a very different initial phase strength are deformed by severe plastic deformation. Nanocrystalline supersaturated solid solutions are reached in all Cu-Co composites independent of the initial composition. The deformation and mechanical mixing process is studied thoroughly by combining scanning electron microscopy, transmission electron microscopy, three-dimensional atom probe tomography and nano indentation. The indentation hardness of the Cu and Co phase and its evolution as a function of the applied strain is linked to deformation and mechanical mixing process to gain a better understanding how the phase strength mismatch of the Cu and Co phase effects the amount of co-deformation and deformation-induced mixing. Our results show that co-deformation is not a necessary requirement to achieve mechanical mixing. (C) 2016 Acta Materialia Inc. Published by Elsevier Ltd. This is an open access article under the CC BY license.
10.1016-j.actamat.2016.08.068	-1		This work describes a high-throughput experimental method to characterize compositional trends in the glass forming ability and mechanical behavior of a ternary metallic alloy system. Continuously-graded composition libraries of Cu-Zr-Ti ternary alloys were produced by laser deposition, and continuous regions of glass-forming compositions were rapidly identified through an optical microscopy technique. By varying the laser processing parameters and thereby the cooling rate of the melt within each library, the composition with the greatest glass-forming ability within the range studied was determined to be Cu51.7Zr36.7Ti11.6. An alternative deposition scheme was applied to fabricate libraries containing a large array of discrete compositions. Instrumented nanoindentation was performed on the discrete libraries to establish compositional trends in the measured. properties. The indentation modulus was observed to be strongly correlated with the Ti-content over the entire region of study, while the hardness was more sensitive to Cu for high Zr-contents and to Ti at lower Zr-contents. These trends could inform the design of new metallic glass alloys possessing an optimized balance of both ductility and glass forming ability.
10.1016-j.actamat.2016.09.024	-1		Severe plastic deformation (SPD) always leads to the strong grain refinement in the materials. Logically, in two- and multiphase alloys SPD has to cause the fragmentation and dissolution of precipitates in a matrix. However, it has been observed recently, that, contrary to this generally accepted viewpoint, SPD can lead also to the decomposition of supersaturated solid solution. In this work we analyze for the first time (both experimentally and theoretically) the competition of these simultaneous processes can take place, namely (1) the dissolution of precipitates and (2) decomposition of supersaturated solid solution with precipitation of a second phase. As a result, a dynamic equilibrium between these two processes appears, and a certain steady-state concentration in a solid solution is reached. In this work we study the high pressure torsion (HPT) of a two-phase Cu-3.9 at. % Ag alloy in two different states: (i) as-cast consisting of a (Cu) solid solution with diluted 1.9 at% Ag and another 2 at% Ag as fine silver precipitates and (ii) an almost homogeneous solid solution with diluted 3.9 at% Ag obtained by homogenization at T = 780 degrees C, 900 h and subsequent water quenching. HPT at room temperature causes the partial dissolution of precipitates in the as-cast samples and partial decomposition of the solid solution in homogenized samples. After HPT, the solute concentration in the matrix is the same in both samples (about 2.9-3.0 at% Ag). Thus, it does not depend on the initial state and is higher than the equilibrium solubility limit at the HPT temperature. This concentration is equal to solubility limit at the effective temperature of T-eff approximate to 680 degrees C. We also proposed the model describing the dynamic equilibrium between dissolution and precipitation in HPT. Assuming that HPT fixes the composition at matrix-precipitate interfaces, we show that HPT-enhanced diffusive transport of species is the process likely controlling the observed steady-state composition in the matrix and precipitate average diameter.
10.1016-j.actamat.2016.10.036	-1		Nanoparticles are of considerable interest, owing to their size-dependent properties, different from those of bulk materials. For revealing internal atomic processes in them, individual nanoparticles of Cu-Ag alloys were grown by direct current (DC) magnetron sputtering. Phase-separation during growth in Cu-Ag particles was found to be size- and composition-dependent. Particles below 5 nm in diameter grow as a solid solution of the components for all compositions (15-80 at% Ag). In the low Ag content range (15 and 30 at% Ag) phase-separation occurs only for particles above 5 nm in diameter. The separation into Cu-rich and Ag-rich domains, when observed, takes place by spinodal decomposition for all particle sizes. In particles undergoing incomplete coalescence, phase-separation occurs even if the diameter of the colliding particles is below 5 nm. In the higher Ag content range (60-80 at%), however, no phase-separation is observed until coalescence sets in. Lattice parameter measurements in alloy particles of 30 at% Ag revealed that the miscibility gap in individual particles varies between 70 and 90 at%. Calculation of the composition dependence of the critical length for spinodal decomposition provided quantitative explanation for the observed phenomena.
10.1016-j.actamat.2016.12.003	4	transformation; martensite; martensitic; phase; shape; beta; memory; shape memory; temperature; temperatures; martensitic transformation; gamma; transformation temperatures; effect; thermal	Severe plastic deformation (SPD) frequently induces phase transformations like decomposition of supersaturated solid solution, dissolution of precipitates, amorphization, nanocrystallization etc. Such diffusive phase transitions are combined with SPD-driven accelerated mass transfer. Displacive (or martensitic) phase transitions can also take place and in combination with diffusive ones have not been investigated in depth in severely deformed materials. The goal of this work is to investigate the combination of displacive (austenite <-> martensite) and diffusive (decomposition of supersaturated solid solution) phase transitions in two different Cu-Al-Ni shape memory alloys under the influence of high-pressure torsion (HPT). After homogenization in the one-phase (austenitic) beta-area of Cu-Al-Ni phase diagram and quenching, the first alloy was in martensitic state (mainly beta'(3) martensite with a small amount of gamma'(3) martensite), and the second one remained austenitic (beta(3) phase). The HPT of these alloys led to the precipitation of alpha(1)-phase in the first case and gamma(1)-phase in the second one (as if they were annealed at an effective temperature T-eff = 620 +/- 20 degrees C). As a result of precipitation, the matrix in the first alloy was enriched and in the second one depleted in Al. After HPT, both alloys contained mainly beta'(3) martensite with a certain amount of gamma'(3) martensite. Thus, the HPT-driven diffusive transformations (precipitation of alpha(1)-and gamma(1)-phase) influence the followed displacive (martensitic) transformation. Simultaneously, a dramatic grain refinement is obtained and the reported results open new possibilities to investigate the superelastic and shape memory effects in nanostructured Cu-Al-Ni alloys.
10.1016-j.actamat.2016.12.057	-1		Nb solute behavior and its effect on grain size stabilization in Cu-Nb alloys was studied using a combination of Vickers hardness testing, x-ray diffraction measurements, transmission electron microscopy and atom probe tomography (APT). Cu-Nb alloys with concentrations in the range of 1 to 10 at% Nb were studied after annealing at 400 degrees C and 800 degrees C. The grain growth resistance at both temperatures increased with an increase in Nb solute content. For instance, after annealing at 800 C (0.74 T-m), Cu-1Nb, Cu-5Nb and Cu-10Nb have a grain size that is similar to 8, similar to 14 and similar to 14 times respectively smaller than that of unalloyed Cu. This resistance is attributed to the formation of Nb-oxide-based clusters, elemental Nb segregation zones and large elemental (Nb)-based precipitates as observed by APT. The Nb-oxide-based clusters are the precursors of phase separation and form due to a reaction with oxygen, which is a contaminant from the milling process. Once the oxygen is consumed, the process continues and the grain boundaries accumulate more solute and begin to thicken into elemental Nb segregation zones. Eventually, Nb solute phase separates and forms Nb-based precipitates. After annealing at 400 degrees C and 800 degrees C, Cu-5Nb has a hardness which is approximately 2.5 times and 3 times respectively that of the hardness of unalloyed Cu after an equivalent anneal. This increase has been attributed to Hall-Petch strengthening and precipitation strengthening.
10.1016-j.actamat.2017.03.080	7	irradiation; shear; grain; ta; deformation; size; radiation; voids; nanocrystalline; simulations; similar; void; temperature; irradiated; boundaries	Irradiation by 1.8 MeV Kr ions at room temperature (RT) was employed to induce nanoprecipitation in two Cu-Mo-Si ternary alloys, Cu96Mo1Si3 and Cu90Mo3.5Si6.5. The nature and the stability of these precipitates during high temperature annealing and irradiation were studied using X-ray diffraction and transmission electron microscopy. In Cu90Mo3.5Si6.5, Kr irradiation at RT resulted in the formation of a high number density (>10(23) m(-3)) of Mo-Si rich nanoprecipitates, similar to 3 nm in size, the formation of which was attributed to Mo-Si interactions during the thermal spike phase of displacement cascades. The size of these irradiation-induced Mo-Si precipitates remained unchanged after annealing at 750 degrees C for 1hr. This near absence of thermal coarsening contrasted with a significant thermal coarsening of the more Mo-rich precipitates formed by direct annealing in that same ternary alloy, and with the even larger coarsening of pure Mo precipitates formed by RT irradiation in binary Cu-Mo alloys. During high temperature irradiation, precipitation is also observed, and some precipitates were significantly enriched in Mo. As for thermal annealing, those precipitates displayed increased coarsening. The remarkable thermal coarsening resistance of RT irradiation-induced Mo-Si precipitates is attributed to the suppression of Mo solubility in a Cu matrix containing Si-rich precipitates, and to the narrow precipitates size distribution generated by RT irradiation. This former point was quantified using thermodynamic calculations with the CALPHAD method.
10.1016-j.actamat.2017.05.007	-1		The magnetron sputtering technique was employed to prepare Zr-alloyed Cu thin films with Zr addition ranging from 0 to 7.0 at%. Microstructure evolution with Zr doping was characterized by using the transmission electron microscope and atom probe tomography. Plastic deformation characteristics (hardness, strain rate sensitivity and activation volume) of the Cu-Zr alloyed films were examined by using nanoindentation testing. Significant Zr doping effects on the microstructure were clearly uncovered that (i) the Zr segregated at grain boundaries and tuned the grain boundary structure. With increasing the Zr addition, CuZr amorphous particles at grain boundaries (3.0 at% Zr) and even three dimensional CuZr amorphous grain boundary network (7.0 at% Zr) were formed; (ii) the grains (size and morphology) and nanotwins were notably influenced by the Zr doping. In particular, the nanotwin thickness was reduced from similar to 25 nm in the pure Cu film down to 5 nm in the Cu-Zr alloyed films. Accompanied with the microstructure evolution, the Cu-Zr thin films displayed hardness and strain rate sensitivity highly sensitive to the Zr doping, i.e., hardness increasing while strain rate sensitivity decreasing with raising the Zr addition. The strengthening and deformation mechanisms were discussed in terms of the microstructure-property relationship. Three regimes were divided within the studied Zr doping range: grain/nanotwin boundary-dominated strengthening mechanism in the regime I of pure Cu film, dislocation nucleation-controlled nanotwin softening mechanism in the regime II of Zr addition <= 3.0 at%, and intergranular amorphous layer-mediated strengthening mechanism in the regime III of Zr addition up to 7.0 at%. In addition, the reduction in strain rate sensitivity with Zr doping was quantitatively described by adopting a model that involves the thermally activated partials depinning mechanism based on the effective dislocation segment length .
10.1016-j.actamat.2017.05.011	6	grain; deformation; strain; strength; dislocation; cu-; tensile; size; ecap; grain size; sfe; ductility; hardening; high; stress	The effect of stacking fault energy on slip to twin shear changeover in soft oriented single crystals of single phase Cu-Al alloys loaded in tension, was investigated. The single crystals of stacking fault energy between 4 mJ/m(2) and 7.5 mJ/m(2), or alternatively of a solute content between 11.5 at%Al and 7.5 at%Al, were able to twin during room temperature tensile deformation performed at a strain rate of 10(-4)s(-1). For other stacking fault energy values, lower than 4 mJ/m(2) and higher than 7.5 mJ/m(2), the crystal lattice shear was produced by slip. It was also found, that as the stacking fault energy decreases from 7 mJ/m2 to 4 mJ/m(2), the twinning stress increases from 90 MPa to 110 MPa and for the lower values approaching 3 mJ/m(2) is expected to exceed 160 MPa. To rationalize the existence of the stacking fault energy window and the inversely proportional dependence of twinning stress, a conversion of mutual work hardening rates of twin and slip systems was found via latent hardening type experiments. It is postulated, that the conversion results from the stacking fault energy controlled transformation of forest dislocations from un-extended into extended dislocation configurations. Additionally, a dual role of material stacking fault energy on the activation of twinning and twinning stress of face-centered cubic materials is emphasized.
10.1016-j.actamat.2017.05.024	-1		Fe grain boundary diffusion is measured in 99.995 wt% pure Cu and the Cu-Fe alloys with iron contents of 0.18, 0.45, 0.6 and 0.8 wt. % using the radiotracer technique and applying the Fe-59 isotope. A series of isothermal experiments at 1000 K reveal that the triple product of iron grain boundary diffusion is almost independent on the iron content excepting the alloy containing 0.8 wt. % of Fe where the triple product is increased by three orders of magnitude. Additional experiments at 1100, 900 and 717 K using this alloy confirm the anomaly observed at 1000 K, namely the triple product is continuously increasing following the Arrhenius dependence from 717 to 1100 K except the temperature of 1000 K, where the triple product is anomalously high . The observed experimental results are explained by the analysis of thermodynamic equilibrium and solubility of Fe and S in Cu.
10.1016-j.actamat.2017.07.039	-1		We report the thermal stability of supersaturated CuCr nanocrystallines alloys at the atomic resolution using modern spherical aberration-corrected transmission electron microscopy (TEM) via performing in situ structural and spectroscopy experiments. It is found that CuCr nanocrystallines are not only subjected to a structural change but also undergo a chemical evolution upon annealing. Chemical destabilization of supersaturated CuCr nanocrystallines occurs at a quite low temperature. Heating triggers a rapid separation of Cu and Cr grains at the forced intermixing zone, accompanied by an obvious decrease of average interface width whereas the grain growth is not significant. Elemental profiles and images recorded in real time reveal that the local compositions vary with heating, which in turn permits to derive the concentration of excess vacancy generated by deformation and observe its evolution with temperature, further to analyze the dynamic behavior in nanocrystalline materials. Electronic structure changes at the interface forced intermixing zone are revealed by the fine structure analysis. The study uncovers the interplay between the thermal stability and chemical decomposition process of bulk nanostructured materials in real-time. (C) 2017 Acta Materialia Inc. Published by Elsevier Ltd.
10.1016-j.actamat.2017.08.041	-1		High pressure torsion (HPT) experiments have been carried out at very low temperatures (-78 degrees C) on dilute Cu-Nb alloys. The samples were prepared by magnetron sputtering to create solid solutions containing nominally between 1 at% and 10 at% Nb. Some samples were pre-annealed.to 700 degrees C to form large Nb precipitates, similar to 75 nm in radius, prior to HPT. For the unannealed alloys, HPT at low temperatures led to alloy decomposition for alloys with concentrations greater than similar to 2 at% Nb, with the steady state concentration of Nb increasing from similar to 1.5 to similar to 3 at% as the initial concentration of Nb was increased. It was also observed that BCC Nb precipitates formed during low-temperature HPT, with a steady state precipitate size similar to 10 nm in radius, which was insensitive to alloy concentration. HPT of pre-annealed Cu-10 at% alloy led to the same steady state microstructure as the unannealed sample, indicating that the steady state during the low temperature HPT process is independent of the initial state for these Cu-Nb alloys. A model for phase evolution in strongly immiscible alloys during severe, low-temperature deformation is offered and implemented' through kinetic Monte Carlo simulations. Good agreement with experiment is obtained.
10.1016-j.actamat.2017.09.039	7	irradiation; shear; grain; ta; deformation; size; radiation; voids; nanocrystalline; simulations; similar; void; temperature; irradiated; boundaries	Tuning the microstructure to optimize the mechanical performance of nanocrystalline Cu thin films via the alloying strategy is quite important for their application in microdevices. In this work, we prepared nanocrystalline miscible Cu-Ti and immiscible Cu-Mo alloyed thin films to investigate alloying effects on the microstructure and mechanical properties of Cu thin films in terms of mixing enthalpies. It is found that the dopants of both Ti and Mo can notably refine the grains, and in particular promote the formation of nanotwins below a critical content of solute, beyond which the formation of nanotwins is notably suppressed. The nonmonotonic solute concentration-dependent twinning behavior observed in Cu-Ti and Cu-Mo alloyed thin films is explained by the coupling effects between grain size and grain boundary segregated dopants that affects the stimulated slip process of partials. The increased hardness of both Cu-Ti and Cu-Mo systems with increasing the solute contents are quantitatively explained by combining several strengthening mechanisms, including solid solution strengthening, grain/twin boundary (GB/TB) strengthening, solute segregation-induced strengthening. It unexpectedly appears that with increasing the solute contents, the Cu-Ti system exhibits monotonically reduced positive strain rate sensitivity (SRS, m), whereas the Cu-Mo system manifests almost constant negative SRS. The fundamental difference in SRS m between Cu-Ti and Cu-Mo is rationalized in terms of the interactions between solute atomic clusters and dislocations based on the cross-core diffusion mechanism.
10.1016-j.actamat.2017.10.057	7	irradiation; shear; grain; ta; deformation; size; radiation; voids; nanocrystalline; simulations; similar; void; temperature; irradiated; boundaries	In this study, the uniaxial tension-tension fatigue behavior of fully nanotwinned magnetron sputtered Cu-6wt%Al, Cu-2wt%Al, and Cu-10 wt%Ni is presented. These alloys have average twin thicknesses ranging from 4 to 8 nm, average grain widths from 90 to 180 nm, and tensile strengths from I to 1.5 GPa. In the high cycle regime (10(3) to 10(7) cycles), the nanotwinned alloys exhibit fatigue strengths ranging from 210 to 370 MPa, which is higher than previously observed in nanotwinned Cu (fatigue strengths between 80 and 200 MPa). Fatigue strengths are normalized by tensile strength for Cu alloys with different microstructures to study the correlation between tensile and fatigue properties. Post-mortem analysis of the materials reveals a newly observed deformation mechanism, where localized detwinning leads to intergranular fracture between columnar grains. Overall, materials displaying detwinning as a deformation mechanism show lower normalized fatigue strengths in comparison to materials that deform with slip band like behavior.
10.1016-j.actamat.2017.11.019	-1		As a significant scientific problem directly impacting on the long-term safety of engineering materials and facilities, the improvement of fatigue strength under fully-reversed cycling was comprehensively explored in this study. Advantageous material characteristics for the improvement of fatigue strength were summarized from the achievements of the previous researches, followed by a new attempt to combine them in material design. As the model material, alpha-Cu-Al alloys with clean ultrafine-grains as well as large proportions of twin boundaries were thus produced, which exhibited a notable fatigue strength improvement (up to 155% higher than the coarse-grained counterparts and 40% higher than the counterparts produced by severe plastic deformation). Furthermore, a general principle briefly summarized as localized fatigue damage reduction was proposed based on the analysis of the optimizing methods including microstructure optimization and composition optimization. Accordingly, several recommended features to obtain such high fatigue strength materials were finally listed for further anti fatigue design, such as uniform grains with small size and stable boundaries; low initial dislocation density, and proper alloying composition. Published by Elsevier Ltd on behalf of Acta Materialia Inc.
10.1016-j.actamat.2018.01.027	7	irradiation; shear; grain; ta; deformation; size; radiation; voids; nanocrystalline; simulations; similar; void; temperature; irradiated; boundaries	Nanocrystalline Cu-Ta alloys are emerging as a new class of structural materials preserving the nano scale grain size up to the melting point of Cu. This extraordinary structural stability is caused by the strong pinning of grain boundaries (GBs) by Ta nano-clusters precipitating from the unstable solid solution after mechanical alloying. Many aspects of the Ta stabilization effect remain elusive and call for further experimental and simulation work. In previous atomistic computer simulations of stress-driven GB migration [JOM 68, 1596 (2016)], the GB cluster interactions in Cu-Ta alloys have been studied for several different compositions and GB velocities. The results have pointed to the Zener pinning as the main mechanism responsible for the grain stabilization. This paper extends the previous work to the motion of individual GBs driven by capillary forces whose magnitude is similar to that in real nano crystalline materials. Both the impingement of a moving GB on a set of Ta clusters and the GB unpinning from the clusters are studied as a function of temperature and alloy composition. The results demonstrate a quantitative agreement with the Zener pinning model and confirm the unzip mechanism of unpinning found in the previous work. In the random Cu-Ta solid solution, short-circuit Ta diffusion along stationary and moving GBs leads to the nucleation and growth of new GB clusters, which eventually stop the GB motion.
10.1016-j.actamat.2018.01.038	-1		The existence of the miscibility gap in the Cu-Ni system has been an issue in both computational and experimental discussions for half a century. Here we propose a new miscibility gap in the Cu-Ni system measured in nano-layered films by Secondary Neutral Mass Spectrometry. The maximum of the symmetrical miscibility curve is around 780K at Cu50%Ni50%. This is the first experiment determining the miscibility from the measurement of the atomic fraction of Copper and Nickel in the whole composition range.
10.1016-j.actamat.2018.01.058	-1		Impurities are often driven to segregate to grain boundaries, which can significantly alter a material's thermal stability and mechanical behavior. To provide a comprehensive picture of this issue, the influence of a wide variety of common nonmetallic impurities (H, B, C, N, O, Si, P and S) incorporated during service or materials processing are studied using first-principles simulations, with a focus on identifying changes to the energetics and mechanical strength of a Cu Sigma 5 (310) grain boundary. Changes to the grain boundary energy are found to be closely correlated with the covalent radii of the impurities and the volumetric deformations of polyhedra at the interface. The strengthening energies of each impurity are evaluated as a function of covalent radius and electronegativity, followed by first-principles-based tensile tests on selected impurities. The strengthening of a B-doped grain boundary comes from an enhancement of the charge density among the adjacent Cu atoms, which improves the connection between the two grains. Alternatively, the detrimental effect of 0 results from the reduction of interactions between the Cu atoms. This work deepens the understanding of the possible beneficial and harmful effects of impurities on grain boundaries, providing a guide for materials processing studies.
10.1016-j.actamat.2018.02.011	-1		We establish an atomistically-informed model for predicting the non-Schmid behavior of critical stresses for bcc to orthorhombic (L2(1) to 18R) martensitic transformation in CuZnAl alloys. The interplay between the stacking fault displacements and the applied stress tensor components are shown to be responsible for the variation of the CRSS levels as much as a factor of almost 2.5 (25 MPa-60 MPa) depending on the crystal orientation. The predicted transformation stresses exhibit excellent agreement with the experimental results in this study and the measurements reported in the literature. The possible role of deviations from crystallographic ordering was also investigated illustrating the increase in transformation stress levels upon introduction of local disorder.
10.1016-j.actamat.2018.02.054	6	grain; deformation; strain; strength; dislocation; cu-; tensile; size; ecap; grain size; sfe; ductility; hardening; high; stress	The main principles of grain boundary engineering of an ultrafine grained microstructure are studied via a systematic variation of the stacking fault energy (gamma(SFE)), solid solution effects (SSEs) and the homologous deformation/annealing temperatures choosing the Cu-Ni system as a model case for non-segregating alloys. Cu and Ni are completely miscible and the gamma(SFE) varies strongly with the alloy composition. Ultrafine grained microstructures are produced by high-pressure torsion and their evolution upon annealing is investigated. The thermal stability and the saturation grain sizes after deformation are determined by SSEs. The fraction of deformation twins varies in accordance with the gamma(SFE) The increase of the length fraction of Sigma 3 grain boundaries versus the grain size is found to be governed by the SSEs, whereas the increase of the length fraction of Sigma 9 grain boundaries versus the grain size depends on the gamma(SFE). The results indicate that grain boundary engineering may lead to an optimum ultrafine grained structure, i.e. with a high length fraction of Sigma 3(n) and Sigma 9 grain boundaries of approximately 40%. This is a significantly large fraction in comparison to a not-engineered microstructure and achieved for grain sizes below 1000 nm in alloys close to the equiatomic composition having a low gamma(SFE) and a high melting temperature. This high fraction of Sigma 3(n) grain boundaries (including their conjunctions) proved itself most effective for microstructure stabilization in this virtually non-segregating system. Thus, for Cu50Ni50 and Cu65Ni35, a narrow grain size distribution of small grains, a high hardness and a high fraction of special grain boundaries can be adjusted.
10.1016-j.actamat.2018.03.044	7	irradiation; shear; grain; ta; deformation; size; radiation; voids; nanocrystalline; simulations; similar; void; temperature; irradiated; boundaries	Grain boundary (GB) engineering via alloying opens a pathway to design the interfaces in alloys for tuning their mechanical properties, thus it is quite critical to determine the optimum addition of alloying element. Here, we prepared immiscible Cu-Cr alloyed thin films by non-equilibrium magnetron sputtering deposition to study Cr alloying effects on the microstructure and mechanical properties of Cu thin films. It is found that Cr doping can notably refine the grains and promote the formation of fully nanotwinned columnar grains at low Cr volume concentrations (<=similar to 3.7 at%) associated with the average GB Cr concentrations <=similar to 15 at%, beyond which the formation of nanotwins is significantly suppressed. The role of Cr atoms/clusters played in the twinning process is rationalized in terms of dislocation rebound-promotion mechanism. Importantly, a maximum hardness is discovered at the optimum Cr addition of similar to 2.0 at%. The Cr concentration-dependent hardness of Cu-Cr alloyed films was quantified by a combined strengthening model. The achievement of the maximum hardness was related to the greatest GB solute segregation-induced strength contribution. It is further uncovered that the Cu-Cr system exhibits strain rate sensitivity (SRS, m) monotonically reduced with increasing the Cr concentration, ranging from a positive m of 0.0314 (for pure Cu) to a negative m of -0.0245, which is attributed to a competition between the dislocation-boundary interactions (increasing m) and the dislocation-solute atoms interactions (decreasing m). These findings provide valuable insights into tuning the composition of alloyed thin films to achieve optimized mechanical performance.
10.1016-j.actamat.2018.05.010	-1		Initially micrometer-sized powder blends of different compositions (Cu-6at%Ag, Cu-37 at%Ag and Cu-84 at%Ag corresponding to Cu-9vol%Ag, Cu-46 vol%Ag and Cu-89 vol%Ag) were deformed by high-pressure torsion for varying applied strain and temperature in order to study their effect on the degree of supersaturation and the prevailing deformation mechanisms. The resulting microstructures were comprehensively characterized with synchrotron X-ray diffraction and transmission electron microscopy. A gradual transition from complete supersaturation to complete phase separation was observed with increasing processing temperature. The critical temperature for full supersaturation strongly depended on the composition. In composites with low Ag and Cu contents single-phase alloys could be obtained up to processing temperatures of 100 degrees C. In the medium composition range strain localization in shear bands prevented full supersaturation for room temperature deformation. Only in regions deformed by shear bands a complete single-phase supersaturated solid solution was obtained, while the lamellar matrix retained a dual-phase structure. By lowering the processing temperature, using liquid nitrogen as coolant, a homogenous single-phase alloy could be also attained at medium compositions. The present results unravel a clear correlation between dominating deformation mechanisms and the degree of deformation-induced supersaturation.
10.1016-j.actamat.2018.06.013	-1		Tensile tests were carried out in high-purity, polycrystalline copper alloys with three concentrations of sulfur impurities (14, 27 and 7920 at ppm) at temperatures between 20 degrees C and 400 degrees C. The ductility drops with increasing sulfur concentration and temperature while the ultimate tensile strength increases. The alloys exhibit a grain size of several millimeters and contain mostly random grain boundaries (GBs). The microstructure and composition is investigated by transmission electron microscopy (TEM) and atom probe tomography (APT). The microstructure of the samples with sulfur contents of 14 and 27 ppm consists of globular grains and neither of the microanalytical techniques employed reveals the formation of Cu-sulfides or sulfur segregation to GBs. Even after annealing at 500 degrees C, no sulfide formation or sulfur segregation to GBs was detected. In the alloy with a sulfur content of 7920 ppm, a dendritic structure is observed and in the interdendritic region monoclinic Cu2S precipitates with a size range from 5 nm to several mu m are observed at GBs and also within the grains. The influence of Son the ductility is discussed considering the TEM and APT results.
10.1016-j.actamat.2018.07.040	-1		The addition of minor elements to binary amorphous alloys often results in simultaneous improvement in plasticity and strength . This is particularly the case for alloy systems that promote atomic-scale compositional separation during quenching. Considering that plasticity and strength are two contrasting properties originating from different atomic-scale structures characterized by short-range orders (SROs), this experimental observation at first seems contradictory when viewed from an SRO perspective. We performed comparative studies on (Cu0.5Zr0.5)(100-x)Ag-x amorphous alloys using experiments and molecular dynamics (MD) simulations to elucidate how these two mutually exclusive properties can be realized at the same time. MD simulations showed that while the addition of Ag promotes the formation of stable icosahedral orders responsible for improved strength, it also encourages the formation of weak/unstable Ag-bearing polyhedra that mitigate strain localization. In this study, the mechanistic origin of the enhanced plasticity is assessed by introducing a new descriptor that can quantitatively evaluate the characteristics of Ag-bearing polyhedra in terms of their size, softness, population, and spatial uniformity.
10.1016-j.actamat.2018.08.019	-1		The effect of Ge alloying on the growth morphology and intrinsic stress evolution during deposition of Cu thin films is investigated using in situ and real time diagnostics, complemented by ex situ microstructural characterizations. Cu1-xGex alloys with x up to 0.15 were sputter-deposited at room temperature on Si substrates, while measuring simultaneously the substrate curvature evolution and surface differential reflectance spectroscopy during the early stages of growth . All films exhibit a typical compressive-tensile-compressive stress behavior, which underpins the distinct stages of a Volmer-Weber growth mode; however, it is revealed that the Ge content plays a decisive role on the nucleation and coalescence stages. This results in a grain size refinement and development of higher compressive stresses for Ge solute additions up to x = 0.07. At higher Ge contents, the strong chemical affinity between Cu and Ge atoms leads to a germanide compound (Cu5Ge) formation and even higher compressive stress. The stress evolutions are discussed considering the surfactant character of Ge atoms affecting Cu adatom mobility and growth morphology. This study highlights the possibility to tailor the early stages of growth and film microstructure (grain size, texture, surface roughness) by introducing solute concentrations of Ge in Cu films. We also determined for the elemental Cu film the percolation and film continuity thicknesses and discussed theses values with respect to those reported for other metallic films.
10.1016-j.actamat.2018.10.013	-1		The mechanical properties of metallic materials are determined by their microstructure, and in particular, the different morphologies of precipitates lead to distinct strengthening effects. Usually, the shape of precipitates changes during growth and coarsening regimes, leading to modification of the macroscopic properties of the materials. Thus, understanding of this phenomenon is key to tailoring the precipitate strengthening of industrial alloys. In this article, a general approach to explain the shape instability of iron-rich nanoparticles in Cu-Fe-Co alloys during casting and ageing processes is proposed. The evolution of particle shape from sphere to cuboid to petal and finally splitting into eight subnanoparticles is observed using transmission electron microscopy. Phase-field modelling and thermodynamic calculations are combined into a general model that describes and elucidates the morphological evolution of precipitates in alloys in terms of particle size, interfacial and elastic strain energy, and chemical driving force. These findings have the potential to promote new microstructural design approaches for a wide range of materials.
10.1016-j.actamat.2018.10.055	-1		Both continuous and discontinuous precipitation is known to occur in CuAg alloys. The precipitation of Ag-rich phase has been experimentally investigated by atom probe tomography and transmission electron microscopy after ageing treatment of Cu-5%wtAg at 440 degrees C during 30'. Both continuously and discontinuously formed precipitates have been observed. The precipitates located inside the grains exhibit two different faceted shapes: tetrahedral and platelet-shaped precipitates. Dislocations accommodating the high misfit at the interface between the two phases have also been evidenced. Based on these experimental observations, we examine the thermodynamic effect of these dislocations on the nucleation barrier and show that the peculiar shapes are due to the interfacial anisotropy. The appropriate number of misfit dislocations relaxes the elastic stress and lead to energetically favorable precipitates. However, due to the large misfit between the parent and precipitate phases, discontinuous precipitation that is often reported for CuAg alloys can be a lower energetic path to transform the supersaturated solid solution. We suggest that the presence of vacancy clusters may assist intragranular nucleation and decrease the continuous nucleation barrier. We eventually propose qualitative thermo-dynamic and kinetic justifications accounting for the relative importance of homogeneous and discontinuous precipitation modes as a function of temperature.
10.1016-j.actamat.2018.11.045	7	irradiation; shear; grain; ta; deformation; size; radiation; voids; nanocrystalline; simulations; similar; void; temperature; irradiated; boundaries	We use molecular dynamics simulation to study the formation of glasses during severe plastic deformation of crystalline Cu vertical bar Zr nano-layers in a simple shear geometry. The early stage of plasticity is governed by dislocation plasticity. Dislocation-interface interaction induces interface roughening and slow atomic-level intermixing around interfaces. A solid-state crystal-to-amorphous transition starts near the interfaces. At high strain, the interfaces are refined to merge, leading to the formation of an intermixed glassy zone that eventually spans our simulation cell. Dislocation emission is then suppressed and strain is fully accommodated by this glassy phase. We characterize the crystal-to-amorphous transition using local structural measures, such as the pair distribution function and Voronoi analysis. The onset of glass formation occurs at a critical shear strain that increases with layer thickness. Our simulations indicate that the parameter controlling this onset is the theoretical affine interface distance, i.e. the amorphization occurs at a critical value of around 3-4 nm that increases slightly with the increase of layer thickness. Our work provides insights on mechanically driven glass formation in multicomponent systems, as e.g. realized in ball-mills or high-pressure torsion experiments.
10.1016-j.actamat.2018.12.018	-1		Cyclic stresses generally lead to fatigue damage and failure with important implications for material and component design, safety, performance and lifetime costs in major structural applications. Here we present unique results for copper to demonstrate that a thin superficial layer of graded surface nanostructure over a coarse-grained core suppresses strain localization and surface roughening, thereby imparting unprecedented resistance to both low-cycle and high-cycle fatigue without compromising ductility. Progressive homogenization of the surface-graded copper is shown to be superior in fatigue properties compared to that of any of its homogeneous counterparts with micro-, submicro- or nanograined structures. Since the findings here for enhancing resistance to fatigue are broadly applicable to a wide spectrum of engineering metals and alloys, the present results offer unique pathways to mitigate fatigue damage using a broad variety of processing routes, geometric design considerations, and structural parameters in many practical applications.
10.1016-j.actamat.2018.12.040	-1		Light elements play a crucial role on the microstructure and properties of conventional alloys and steels. Oxygen is one of the light elements which is inevitably introduced into nanocrystalline alloys during manufacturing. Here, we report that severe plastic deformation can fragment the oxides formed in powder processing and eventually cause oxygen dissolution in the matrix. A comparative investigation on Cu-Fe nanocrystalline alloys generated from different initial materials, blended powders and arc melted bulk materials which have different oxygen contents, reveals that fragmented oxides at grain boundaries effectively decrease the grain boundary mobility, markedly facilitating grain refinement. In contrast, those oxygen atoms dissolved as interstitials in the Cu-Fe matrix lead to lattice expansion and significant decrease of stacking fault energy locally as validated by density functional theory. Such oxygen-mediated microstructure gives rise to enhanced strength and superior structural stability. The remarkable tailoring effect of oxygen can be employed to engineer nanocrystalline materials with desired properties for different applications. (C) 2018 Acta Materialia Inc. Published by Elsevier Ltd. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/).
10.1016-j.actamat.2018.12.047	-1		Cu-Ni-Si alloys have been widely applied in electronic and electrical industries. The precipitation behavior of some of the Cu-Ni-Si alloys is still not well understood. In this study, the precipitation behavior of the Cu-3.0Ni-0.72Si alloy aged at 600 degrees C for different times was investigated by transmission electron microscopy, atom probe tomography and phenomenological theory of precipitation crystallography. A new orientation relationship (OR) between the precipitates and the Cu matrix was found in the over-aged condition and a coarsening mechanism of the metastable precipitates was put forward. The two- and three-dimension invariant line theories were successfully applied in interpreting the evolution of the ORs and the morphologies in the Cu/delta-Ni2Si (Cu/delta) system. At the early stage of aging, the fine metastable delta'-(Cu, Ni)(2)Si precipitates are coherent with the Cu matrix, with a quasi-Bain OR of (110)(Cu)parallel to(100)(delta)', and [001](Cu)parallel to[001]delta', and four pairs of parallel conjugate planes: ((11) over bar1)(Cu)parallel to((3) over bar 01)(delta)', (111)(Cu)parallel to(301)(delta)', ((1) over bar 11)(Cu)parallel to(021)(delta)',, and (1 (11) over bar)(Cu)parallel to(0 (1) over bar1)(delta)'. The precipitates have a delta-Ni2Si structure, with some Ni atoms substituted by Cu atoms. During growth, the core region of the metastable delta'-(Cu,Ni)(2)Si precipitate transforms into stable delta-Ni2Si, with a quasi-NW OR of ((1) over bar 11)(Cu)parallel to(021)delta and [110](Cu)parallel to[100](delta), while a layer of metastable delta'- (Cu, Ni)(2)Si still exists around the core. With prolonging aging time, the delta-Ni2Si precipitates with the OR of ((1) over bar 11)(Cu)parallel to(021)(delta) and [110](Cu)parallel to[100](delta) grow two-dimensionally to form a plate-like shape, while those with the OR of (111)(Cu)parallel to(301)delta and [(1) over bar 10](Cu)parallel to[010](delta) grow one-dimensionally to form a fiber-like shape.
10.1016-j.actamat.2019.01.021	6	grain; deformation; strain; strength; dislocation; cu-; tensile; size; ecap; grain size; sfe; ductility; hardening; high; stress	This paper reports a new type of unique gradient microstructure (i.e., fine-grained core and coarse grained surface regions) fabricated using a continuous severe plastic deformation process for metallic sheets, called single-roll angular-rolling (SRAR). The gradient-structured Cu sheet produced by SRAR has a reverse microstructure that is distinctly different from conventional gradient materials (i.e., fine-grained surface and coarse-grained core regions) created by surface nanocrystalline processes. Finite element analysis demonstrated that the evolution of the gradient microstructure in SRAR is attributable to the heterogeneity of its shear deformation history along the thickness direction due to the combined effect of circumferential shear deformation, equal-channel angular pressing, and frictional effects. The resultant gradient-structured Cu sheet exhibited simultaneous enhancements of strength and ductility. By systematic comparison to homogeneous counterparts, it was confirmed that the extraordinary combination of strength and ductility came from the gradient structural effect. Using the micro-scale digital image correlation method, clear strain partitioning and its corresponding strain gradients were observed. This high plastic-incompatibility was compensated by the pile-ups of geometrically necessary dislocations (GNDs) at the interface between the fine- and coarse-grained layers. The large amount of GNDs resulted in corresponding high back-stress evolution, contributing to the extraordinary strain hardening of the gradient-structured Cu sheet. The SRAR process sheds lights on developing new type of heterogeneous materials applicable to industry.
10.1016-j.actamat.2019.01.037	7	irradiation; shear; grain; ta; deformation; size; radiation; voids; nanocrystalline; simulations; similar; void; temperature; irradiated; boundaries	Nanotwinned metals exhibit outstanding radiation tolerance as twin boundaries effectively engage, transport and eliminate radiation-induced defects. However, radiation-induced detwinning may reduce the radiation tolerance associated with twin boundaries, especially at elevated temperatures. Here we show, via in-situ Kr ion irradiation inside a transmission electron microscope, that 3 at. % Fe in epitaxial nanotwinned Cu (Cu97Fe3) significantly improves the thermal and radiation stability of nanotwins during radiation up to 5 displacements-per-atom at 200 degrees C. Such enhanced stability of nanotwins is attributed to a diffuse 9R phase resulted from the dissociation of incoherent twin boundaries in nanotwinned Cu97Fe3. The mechanisms for the enhanced stability of twin boundaries in irradiated nanotwinned alloys are discussed. The stabilization of nano-twins opens up opportunity for the application of nanotwinned alloys for aggressive radiation environments. (C) 2019 Published by Elsevier Ltd on behalf of Acta Materialia Inc.
10.1016-j.actamat.2019.03.023	7	irradiation; shear; grain; ta; deformation; size; radiation; voids; nanocrystalline; simulations; similar; void; temperature; irradiated; boundaries	Phase evolution in dilute, strongly immiscible Cu-Mo, Cu-Mo-Ni, and Cu-Mo-Ag alloys during severe plastic deformation at low-temperature has been experimentally investigated. For the Cu95Mo05 alloy, Mo nanoparticles are formed, similar to 10 nm in diameter, as part of a steady state microstructure, with less than similar to 1 at% Mo dissolved in the matrix. Addition of 10 or 20 at% Ni to this binary alloy results in a significant increase in the Mo solubility, whereas comparable additions of Ag has a corresponding little effect. The steady state microstructures of alloys during ball milling of elemental powders are very similar to those during HPT processing of initially homogeneous solutions. The results are discussed in terms of an effective temperature model. Model MD simulations are presented to help relate the predictions of the effective temperature model to atomistic mechanisms. Published by Elsevier Ltd on behalf of Acta Materialia Inc.
10.1016-j.actamat.2019.03.039	-1		Dealloying is a selective corrosion process during which the more electrochemically active elements in a parent alloy dissolve while the remaining more noble atoms diffuse along the solid-electrolyte interface, resulting in the formation of a nanoporous microstructure composed of core-shell ligaments. In this work, we study an extension of the physics of dealloying in which the parent alloys (Cu-Fe-Mn alloys) contained an engineered composition of elements selected such that, upon dissolution of one of them, the remaining elements phase separate as they become concentrated in the undissolved ligaments. Such simultaneous dealloying and phase separation leads to the formation of rich variety of new porous structures containing nanocomposite ligaments, as well as unanticipated structure evolution such as nanowire growth that are attributed to solution side effects.
10.1016-j.actamat.2019.06.027	-1		In this atomistic study on the copper-nickel system, a new embedded-atom alloy potential between copper and nickel is fitted to experimental data on the mixing enthalpy, taking available potentials for the pure components from literature. The resulting phase boundaries of the new potential are in very good agreement with a recent CALPHAD prediction. Using this new potential, a high angle symmetrical tilt Sigma 5 and a coherent Sigma 3 twin grain boundary (GB) are chosen for a systematic investigation of equilibrium GB segregation in the semi-grandcanonical ensemble at temperatures from 400K to 800K. Applying thermodynamically accurate integration techniques, the GB formation energies are calculated exactly and as an absolute value for every temperature and composition, which also enables the evaluation of GB excess entropies. The thorough thermodynamic model of GBs developed by Frolov and Mishin is excellently confirmed by the simulations quantitatively, if the impact of both segregation and GB tension on the change in GB formation energy is accounted for. In the case of the Sigma 3 coherent GB, it turns out that the change in GB formation energy at low temperatures is for the most part attributed to the GB tension, while segregation only has a small influence. This demonstrated effect of GB tensions should also be taken into account in the interpretation of experiments.
10.1016-j.actamat.2019.08.031	-1		Building on the recent discovery of tough nanocrystalline Cu-Zr alloys with amorphous intergranular films, this paper investigates ternary nanocrystalline Cu-Zr-Hf alloys with a focus on understanding how alloy composition affects the formation of disordered complexions. Binary Cu-Zr and Cu-Hf alloys with similar initial grain sizes were also fabricated for comparison. The thermal stability of the nanocrystalline alloys was evaluated by annealing at 950 degrees C (>95% of the solidus temperatures), followed by detailed characterization of the grain boundary structure. All of the ternary alloys exhibited exceptional thermal stability comparable to that of the binary Cu-Zr alloy, and remained nanocrystalline even after two weeks of annealing at this extremely high temperature. Despite carbide formation and growth in these alloys during milling and annealing, the thermal stability of the ternary alloys is mainly attributed to the formation of thick amorphous intergranular films at high temperatures. Our results show that ternary alloy compositions have thicker boundary films compared to the binary alloys with similar global dopant concentrations. While it is not required for amorphous complexion formation, this work shows that having at least three elements present at the interface can lead to thicker grain boundary films, which is expected to maximize the previously reported toughening effect.
10.1016-j.actamat.2019.09.021	6	grain; deformation; strain; strength; dislocation; cu-; tensile; size; ecap; grain size; sfe; ductility; hardening; high; stress	A gradient nanostructured (GNS) surface layer was induced on coarse-grained (CG) Cu and CuAl alloys by means of surface mechanical grinding treatment. The GNS/CG Cu-4.5Al sample subjected to tensile tests yields at a higher strength and fails at a higher uniform elongation (similar to 42%) in comparison with the GNS/CG Cu and Cu-2.2Al samples. The microstructures of the GNS/CG samples before and after tension at different strains were systematically investigated by transmission electron microscope. It is revealed that grain coarsening dominates the plastic deformation of nanograins in the GNS/CG Cu sample while the propensity of deformation twinning in nanograins increases in the GNS/CG CuAl samples. The experimental results suggested a transition of deformation mechanism of nanograins from grain coarsening to the partial dislocation associated deformation twinning in the GNS/CG Cu and CuAl alloys with increasing Al solute concentration. The obvious activation of deformation twinning accommodates the large tensile plasticity of the surface nanograins in the GNS/CG Cu-4.5Al sample. This work demonstrated that the partial dislocation associated deformation twinning is an effective deformation mechanism to retard the strain localization and to improve the tensile ductility of nanograins.
10.1016-j.actamat.2019.10.005	7	irradiation; shear; grain; ta; deformation; size; radiation; voids; nanocrystalline; simulations; similar; void; temperature; irradiated; boundaries	The competition between ductile rupture mechanisms in high-purity Cu and other metals is sensitive to the material composition and loading conditions, and subtle changes in the metal purity can lead to failure either by void coalescence or Orowan Alternating Slip (OAS). In situ X-ray computed tomography tensile tests on 99.999% purity Cu wires have revealed that the rupture process involves a sequence of damage events including shear localization; growth of micron-sized voids; and coalescence of microvoids into a central cavity prior to the catastrophic enlargement of the coalesced void via OAS. This analysis has shown that failure occurs in a collaborative rather than strictly competitive manner. In particular, strain localization along the shear band enhanced void nucleation and drove the primary coalescence event, and the size of the resulting cavity and consumption of voids ensured a transition to the OAS mechanism rather than continued void coalescence. Additionally, the tomograms identified examples of void coalescence and OAS growth of individual voids at all stages of the failure process, suggesting that the transition between the different mechanisms was sensitive to local damage features, and could be swayed by collaboration with other damage mechanisms. The competition between the different damage mechanisms is discussed in context of the material composition, the local damage history, and collaboration between the mechanisms.
10.1016-j.actamat.2019.12.005	-1		The influence of solid solution strengthening on the evolution of the microstructure under cyclic dry sliding is still not fully rationalized. One reason is that alloying needed for solid solution strengthening alters the stacking fault energy at the same time and, hence, the mode of dislocation slip in face-centered cubic metals and alloys. Both aspects determine the details of plastic deformation and, therefore, lead to different results under tribological load. A series of Cu-Mn alloys was investigated in the present study, which exhibit wavy slip mode and an almost constant stacking fault energy over a wide solute concentration range. Solid solution strengthening is the main contribution to the hardness in these alloys. The sole impact of changing strength and hardness on the tribological response along with microstructure evolution during tribological load is assessed. After the reciprocating, tribological loading a linear correlation between the wear track width and hardness could be ascertained. Electron microscopy reveals a horizontal discontinuity of the dislocation structure beneath the surface in all alloys at a similar depth . An evaluation of the Hamiltonian elastic stress field model indicates that the depth of the dislocation feature after one sliding pass correlates with the stress distribution as well as the critical stress for dislocation motion. The subsurface microstructure features a transition from the dislocation feature to subgrain formation after about five to ten cycles. Beyond ten cycles, oxide clusters are formed on the sliding surface and the grains elongate in the sliding direction.
10.1016-j.actamat.2019.12.048	7	irradiation; shear; grain; ta; deformation; size; radiation; voids; nanocrystalline; simulations; similar; void; temperature; irradiated; boundaries	Nanocrystalline metals are promising radiation tolerant materials due to their large interfacial volume fraction, but irradiation-induced grain growth can eventually degrade any improvement in radiation tolerance. Therefore, methods to limit grain growth and simultaneously improve the radiation tolerance of nanocrystalline metals are needed. Amorphous intergranular films are unique grain boundary structures that are predicted to have improved sink efficiencies due to their increased thickness and amorphous structure, while also improving grain size stability. In this study, ball milled nanocrystalline Cu-Zr alloys are heat treated to either have only ordered grain boundaries or to contain amorphous intergranular films distributed within the grain boundary network, and are then subjected to in situ transmission electron microscopy irradiation and ex situ irradiation. Differences in defect density and grain growth due to grain boundary complexion type are then investigated. When amorphous intergranular films are incorporated within the material, fewer and smaller defect clusters are observed while grain growth is also limited, leading to nanocrystalline alloys with improved radiation tolerance.
10.1016-j.actamat.2020.05.055	-1		The high-pressure torsion (HPT) of binary copper alloys with 3, 5, 8, 10 wt. % Ag and 14 wt. % Sn has been studied at room temperature T-HPT. Before HPT, the Cu-Ag alloys have been annealed at 12 different temperatures between 320 and 800 degrees C and Cu-14 wt. % Sn has been annealed at 9 different temperatures between 310 and 500 degrees C. Thus, before HPT the Cu-Ag alloys consisted of Ag-particles in the Cu-based matrix with silver content c(init) from almost zero to 8 wt%. The Cu-14 wt. % Sn samples had Cu-based matrix with tin concentration c(init )from almost zero to 14 wt% Sn and precipitates of epsilon or delta Hume-Rothery intermetallic phases. After about 1.5 plunger rotations a certain steady-state concentration c(ss) of the alloying element is reached in the matrix. The measured c(ss) values were 5.5 +/- 0.1 wt. % Ag and 13.1 +/- 0.1 wt. % Sn. If the initial concentration c(init) in Cu matrix was below c(ss) (c(init)< c(ss)), it increased towards c(ss) during HPT. If c(init) > c(ss) it decreased towards c(ss) . We observed that c(ss) did not depend on c(init) in broad interval of c(init) and was, therefore, equifinal. The equifinal c(ss) values corresponded to the certain equilibrium solubilities of silver and tin in Cu matrix and allowed to estimate the (elevated) effective temperature as T-eff (Ag) = 700 +/- 10 degrees C and T-eff (Sn) = 400 +/- 10 degrees C, respectively. The observed phenomena are discussed using the ideas of non-equilibrium thermodynamics of open systems. During HPT the decomposition of a solid solution competed with dissolution of precipitates. As a result, a dynamic equilibrium established between precipitation and dissolution at steady-state deformation stage. In this dynamic equilibrium a certain steady-state concentration c(ss) of the alloying element is reached in the matrix. In Cu-based alloys, the obtained T-eff is always higher than T-HPT and correlates with activation enthalpy of dopant diffusion in Cu. Other HPT-driven phenomena such as accelerated mass transfer, intermetallic phase formation, grain boundary faceting and grain boundary segregation are taken into account to evaluate the effective temperature T-eff.
10.1016-j.actamat.2020.05.061	7	irradiation; shear; grain; ta; deformation; size; radiation; voids; nanocrystalline; simulations; similar; void; temperature; irradiated; boundaries	Nanocrystalline materials are known to possess excellent radiation resistance due to high fraction of grain boundaries that act as defect sinks, provided they are microstructurally stable at such extreme conditions. In this work, radiation response of a stable nanocrystalline Cu-Ta alloy is studied by irradiating with 4 MeV copper ions to doses (close to the surface) of 1 displacements per atom (dpa) at room temperature (RT); 10 dpa at RT, 573 and 723 K; 100 and 200 dpa at RT and 573 K. Nanoindentation results carried out for samples irradiated till 100 dpa at RT and 573 K show exceptionally low radiation hardening behavior compared to various candidate materials from literature. Results from microstructural characterization, using atom probe analysis and transmission electron microscopy, show a stable nanocrystalline microstructure with minimal grain growth and a meagre swelling in samples irradiated to 100 dpa (similar to 0.2%) and 200 dpa at RT, while no voids in those at 573 K. This radiation tolerance is partly attributed to the stability of Ta nanoclusters due to phase separating nature of the alloy. Additionally, the larger tantalum particles are observed to undergo ballistic dissolution at doses greater than 100 dpa and are eventually precipitated as nanoclusters, replenishing the sink strength, which enhanced material's radiation tolerance when exposed to high irradiation doses and elevated temperatures.
10.1016-j.actamat.2020.07.035	-1		Conductive and yet strong copper alloys are essential materials in highly mechanically loaded electrical devices. We demonstrate a novel in-situ synthesis approach via laser metal deposition (LMD) in a lean copper alloy, Cu-3.4Cr-0.6Nb (at%). Strengthening in the lean alloy comes from chromium nano-scale precipitates formed in-situ (4 nm diameter; number density 8 x 10(23) m(-3)) and from Laves phase particles (< 1 mu m diameter; 2.2 vol%), dispersed across the microstructure. This dual dispersion, in a nearly pure copper matrix, is achieved through a suited combination of chromium alloying and cooling rate during LMD synthesis. The as-synthesized alloy has a conductivity of 68% IACS (International Annealed Copper Standard) and a Vickers hardness of 146, at room temperature. The latter is 11% above the value reported for the strongest lean reference ternary alloy Cu-8Cr-4Nb (at%). The in-situ synthesis approach averts any heat treatment step, which has been an essential step previously in conventional manufacturing, for realizing the property combination in lean Cu-Cr based system.
10.1016-j.actamat.2020.10.008	7	irradiation; shear; grain; ta; deformation; size; radiation; voids; nanocrystalline; simulations; similar; void; temperature; irradiated; boundaries	Understanding the void evolution in irradiation environment is of great interest and significance, as irradiation-induced voids typically lead to pronounced volumetric swelling and degradation of mechanical properties. In situ studies on the irradiation response of nanovoids at elevated temperature remain limited. In this work, we performed systematic in situ 1 MeV Kr ++ irradiations on Cu with nanovoids in a transmission electron microscope up to 350 degrees C. The in situ studies revealed intriguing void spheroidization, shrinkage and migration. Furthermore, the morphology evolution and migration of nanovoids showed a strong dependence on irradiation temperature and initial void size. Post-irradiation analyses identified defect clusters in the form of stacking fault tetrahedrons, and the remaining large faceted nanovoids. The underlying mechanisms of irradiation-induced void spheroidization and shrinkage were discussed based on phase-field modeling. Published by Elsevier Ltd on behalf of Acta Materialia Inc.
10.1016-j.actamat.2020.10.076	-1		Coherent precipitation of cuboidal gamma' phase is an efficient strategy to improve high temperature properties in nickel-based alloys. The present work aims to introduce this strengthening mechanism into copper alloys to solve the issue of deficient heat resistance. The results shown that a series of cuboidal gamma' coherent precipitation-strengthened Cu100-y(Ni3/4Al1/4)(y) alloys were obtained in the (Ni+Al) content range of 20 at. % to 50 at. %. These alloys are shown to exhibit excellent comprehensive mechanical properties, high melting point, and a softening temperature of 1273K or more than 1273K. Their hardness and yield strength increased with the rise of temperature, ascribing to splitting of gamma' phase. AFM surface current mode and three-dimensional reconstruction of microstructure was performed to determine that gamma phases remain conductive body in Cu100-y(Ni3/4Al1/4)(y) alloys, and meanwhile temperature-dependent resistivity was characterized and discussed, which showed the improvement of resistivity thermal stability attributing to coherent precipitation of gamma' phase. Comparing to other Cu commercial alloys, cuboidal gamma' phase coherent precipitation-strengthened alloys possess a great potential under high-temperature loads and service environments. In further researches, continued efforts will be required in the multi-component design of Cu100-y(Ni3/4Al1/4)(y) alloys to improve the comprehensive performance.
10.1016-j.actamat.2020.116488	-1		The wetting of A1N by molten Cu-8.6Zr-xTi (x=0, 5, 7.5, and 10 at%) ternary alloys was conducted by the modified sessile drop method at 1373 K under a high vacuum. A1N cannot be wetted by Cu-8.6Zr binary eutectic alloy even though the precipitation of zirconium nitride at interface, while the addition of Ti in Cu-Zr eutectic alloy upgraded the wettability significantly. Based on the thermodynamic analysis, the interfacial reaction sequence leads to the preferential precipitation of zirconium nitride, and thus a bilayer reaction layer (zirconium nitride bottom and titanium nitride upper) was formed at the interface in Cu-8.6Zr-xTi/A1N. The final wettability was determined by the wetting nature of the reaction product (titanium nitride and stoichiometry in it) and the adsorption of Ti addition at interface. The spreading dynamics were further influenced by the interfacial reaction sequence, and presented two stages, first corresponds to the precipitation of zirconium nitride, and then corresponds to the precipitation of titanium nitride.
10.1016-j.actamat.2020.116559	6	grain; deformation; strain; strength; dislocation; cu-; tensile; size; ecap; grain size; sfe; ductility; hardening; high; stress	Cyclic deformation behavior and damage mechanisms of Cu-Mn alloys with high stacking fault energies (SFE) were systemically investigated at constant total strain amplitude in the range of 0.2%-1.0% at room temperature in air. The results demonstrate that the cyclic hardening capacity and fatigue life of the alloy are notably improved with the increase of Mn content. Increasing Mn content significantly affects the damage behavior of the alloy, including a transition of cracking mode from concentrated intergranular cracking to slip band (SB)/intergranular mixed cracking and an enhanced resistance to crack propagation. All these features above are attributed to the transformation of cyclic deformation micromechanisms, i.e., the changes of slip mode from wavy- to planar-slip with increasing Mn content. The existence of short-range ordering (SRO) in Cu-Mn alloys is the essential reason for promoting slip planarity. Based on microstructural characterizations and analyses, the intrinsic connection between the SRO and the cyclic deformation and damage behavior was clarified. In brief, the present study opens another promising window to improve fatigue performance in face-centered cubic alloys especially with high SFE and SRO degree.
10.1016-j.actamat.2021.116650	-1		Amorphous complexions in nanocrystalline metals have the potential to improve mechanical properties and radiation tolerance, as well as resistance to grain growth . In this study, the stability of amorphous complexions in binary and ternary Cu-based alloys is investigated by observing the effect of cooling rate from high temperature on the occurrence of amorphous-to-ordered complexion transitions. Bulk Cu-Zr and Cu-Zr-Hf alloy samples were annealed to induce boundary premelting and then quenched through a procedure that induces a gradient of local cooling rate through the sample height. Amorphous complexion thickness distributions were found to be invariant to local cooling rate in the Cu-Zr-Hf alloy, demonstrating enhanced stability of the amorphous complexion structure compared to the Cu-Zr alloy, which had thinner amorphous complexions in the regions that were slowly cooled. The experimental results are used to construct time-temperature-transformation diagrams for the amorphous-to-ordered complexion transition in both the binary and ternary alloys, enabling a deeper understanding of the influence of cooling rate and grain boundary chemistry on complexion transitions. The critical cooling rate necessary to avoid complexion transitions in the ternary alloy is found to be at least three orders of magnitude slower than that for the binary alloy.
10.1016-j.actamat.2021.116705	-1		Molecular dynamics simulations are performed to investigate the dynamic properties and microstructure of Cu(100-x)Agx (x = 0, 25, 45.8, 75, 100) melts. A dynamic crossover reflecting the Arrhenius-to-nonArrhenius transition and the breakdown of the Stokes-Einstein relationship is found in the melts except for pure Cu and Ag. Different from Cu75Ag25 and Cu25Ag75 melts of which the crossover temperature T-c is below the liquidus temperature, the T-c of Cu54.2Ag45.8 eutectic melt is about 115 K above the eutectic temperature. Around the crossover temperature, abrupt enhancement in the dynamic heterogeneity and breaking of the Stokes-Einstein relationship are also observed. Structural analyses based on chemical short-range order and local topological atomic stacking reveal that the rapid increase of the number of slow particles, the abruptly expanding difference in local atomic structure and the resultant change in diffusion mechanism trigger the abnormal dynamic behavior. The same species of atoms tend to gather into clusters especially at lower temperature. In contrast to Ag atoms whose migration capability does not vary with their positions in the Ag clusters, Cu atoms move slower due to the higher degree of order when they are in the center of the Cu clusters. A roughly empirical relationship between the dimensionless dynamic property D* and excessive entropy S-2 is revealed by using the extended scaling law to the Cu-Ag melts. These findings are highly helpful for an in-depth understanding of the dynamics of eutectic melts.
10.1016-j.actamat.2021.116706	7	irradiation; shear; grain; ta; deformation; size; radiation; voids; nanocrystalline; simulations; similar; void; temperature; irradiated; boundaries	Microstructural instability in traditional nanocrystalline metals limits the understanding of the fundamental effect of grain size on mechanical behavior under extreme environmental conditions such as high temperature and loading rates. In this work, the interplay between Ta concentrations and processing temperature on the resulting microstructure of a powder processed, fully dense Cu-Ta alloy along with their tensile and compressive behavior at different strain rates are investigated to probe the possibility of manipulating or tuning microstructurally dependent parameters to control the flow-stress upturn phenomenon. Consequently, the results reveal that there is a crucial length scale, i.e., small grain size and appropriate cluster spacing, below which such upturn is damped out. The observation of changes in flow stress upturn behavior is consistent with the observed changes in measured high-rate plasticity, which enhances below the critical length scale. Furthermore, tension-compression asymmetry also tends to be suppressed in nanocrystalline Cu-Ta alloys, while it becomes evident as the grain size increases to an ultrafine regime. Overall, this work presents a systematic approach to control or engineer reduced high strain rate flow stress upturn behavior in metallic alloys, for high-rate applications.
10.1016-j.actamat.2021.116812	7	irradiation; shear; grain; ta; deformation; size; radiation; voids; nanocrystalline; simulations; similar; void; temperature; irradiated; boundaries	In situ irradiations with 1 MeV Kr ions at 50 similar to 613 K up to a fluence of 6.25 x 10(14) ions/cm(2) (similar to 1.25 displacements per atom, dpa) have been performed on pre-aged dilute Cu-0.9%Co, Cu-0.9%Fe and Cu-0.8%Cr alloys containing uniform matrix dispersions of coherent precipitates in order to study the effects of initial precipitate sink strength, damage dose and irradiation temperature on radiation-induced coherency loss of precipitates. Coherent precipitates with different point defect sink strengths (2 pi Nd, where N and d are the precipitate density and diameter) were used in this work to examine potential differences in atomic relaxation during absorption of point defects. In all cases, irradiation to low doses (
10.1016-j.actamat.2021.116923	11	glass; bulk; metallic; bulk metallic; gfa; bmg; glassy; metallic glass; ability; bulk metallic glass; amorphous; addition; crystallization; mm; glass-forming	The effects of minor sulfur addition on the glass-forming ability (GFA), phase formation, thermal stability, and mechanical properties of the Cu47.5Zr45.1Al7.4 bulk metallic glass (BMG) were studied by conventional X-ray diffraction (XRD), in-situ high-energy synchrotron XRD, calorimetry, thermomechanical analysis, and scanning electron microscopy. Results show that sulfur has positive and negative effects on the GFA and thermal stability of Cu-Zr-Al alloys. On the one hand, sulfur can slow down the liquid dynamics, thus inhibiting the precipitation of eutectic phases during casting from the melt and heating from the as-cast glass, and hence favoring the glass formation and thermal stability of the sulfur-bearing alloys. On the other hand, the addition of sulfur promotes the formation of an Al-rich tau(3) phase, which easily precipitates and is therefore catastrophic for the GFA and melt stability. The two factors compete with each other and ultimately lead to an optimal sulfur content of 0.75 at% for the investigated Cu-Zr-Al alloys. Compared with the base alloy, this novel sulfur-containing BMG possesses improved GFA, enlarged supercooled liquid region, and comparable mechanical strength and toughness, making it a promising candidate for industrial applications as structural material. Furthermore, the schematics of the change in time-temperature-transformation diagrams with increasing sulfur concentration were proposed on the basis of experimental results.
10.1016-j.actamat.2021.116960	-1		In this work, we experimentally establish the isothermal nanofacet evolution at an asymmetric Sigma 5 tilt grain boundary in the Cu-Ag system using a diffusion couple approach . We investigate the nanofacet formation along the grain boundary in dependence of the Ag solute excess concentration. The initial grain boundary dissociates into asymmetric Ag-lean segments and Ag-rich symmetric (210) segments. Increasing Ag excess leads to an increase in Ag-rich facet segment length, while the length of the asymmetric facets remains constant. From this, we construct a grain boundary nanofaceting diagram deduced from our experiments relating local atomic structure, overall inclination and Ag solute excess. (C) 2021 The Author(s). Published by Elsevier Ltd on behalf of Acta Materialia Inc.
10.1016-j.actamat.2021.116993	-1		A novel method for measurement of atomic interdiffusivity is applied to amorphous Cu-Zr close to its glass-transition temperature T-g. Sputter-deposited multilayers are examined in cross-section by transmission electron microscopy and energy-dispersive X-ray spectroscopy. Mapping the evolution of composition profiles gives the interdiffusivity, which is orders of magnitude higher than if coupled to the viscosity expected near T-g. Kirkendall drift of interlayer interfaces in both amorphous and supercooled liquid states (i.e. below and above T-g), and associated voiding in the liquid, show that the diffusivity of copper greatly exceeds that of zirconium. Amorphous Cu-Zr is known to show maxima in atomic packing density at sharply defined compositions. The comparison of the two compositions in the present work provides the first direct evidence that denser packing is associated with lower atomic interdiffusivity. The lower interdiffusivity is governed by a lower diffusivity of copper, and reflects a lessened degree of decoupling of the copper (fast) and zirconium (slow) diffusivities in an efficiently packed glass. The new insights help to understand issues ranging from glass-forming ability to the controlled generation of nanovoided structures. (C) 2021 The Author(s). Published by Elsevier Ltd on behalf of Acta Materialia Inc.
10.1016-j.actamat.2021.117073	-1		The presence of a gradient layer with an increased maximum microhardness and extended thickness is extremely attractive because it can enhance the service performances for surface-strengthened metallic materials. In this research, Cu-Al alloys with different Al contents and microstructures were processed by surface spinning strengthening (3S) and studies were conducted to examine the gradient microstructure and microhardness distributions of the 3S Cu-Al alloys. The experimental results show that each group of the 3S Cu-Al alloys having the same Al content has approximately the same maximum microhardness at the topmost surface layer and the maximum microhardness increases with an increase in the Al content. In addition, the thickness of the gradient layer in the 3S Cu-Al alloys increases with a decrease of yield strength and an increase in the work-hardening exponent, respectively. The relationship between the maximum microhardness and chemical composition which determines the Young's modulus and plastic deformation mode, and the relationship between the thickness of the gradient layer and the microstructure which governs the strength and work-hardening capacity, were both investigated. It is found that the maximum microhardness of the gradient layer depends mainly on the chemical composition; whereas the thickness of the gradient layer depends primarily on both the strength and work-hardening capacity which are closely related to the microstructure. By combining the compositional design and microstructure optimization of the materials, and improving the surface strengthening intensity, a gradient layer of the surface-strengthened materials with an enhanced maximum microhardness and an extended thickness may be achieved.
10.1016-j.actamat.2021.117118	-1		Optimizing the composition and improving the conflicting mechanical and electrical properties of multiple complex alloys has always been difficult by traditional trial-and-error methods. Here we propose a machine learning strategy to design alloys with remarkable properties by screening key alloy factors through correlation screening, recursive elimination and exhaustive screening, and then designing composition iteratively through Bayesian optimization. Taking the precipitation strengthened copper alloys as an example, 5 kinds of key alloy factors affecting hardness (HV) and 6 kinds of key alloy factors affecting electrical conductivity (EC) were obtained by screening alloy factors. HV-key alloy factors model with error less than 7% and the EC-key alloy factors model with error less than 9% were established, respectively. Then, new copper alloys were effectively designed utilizing Bayesian optimization and iterative optimization experiments. Designed Cu-1.3Ni-1.4Co-0.56Si-0.03Mg alloy has excellent combined mechanical and electrical properties with the measured ultimate tensile strength (UTS) of 858 MPa and EC of 47.6%IACS. The property results are superior to the reported precipitation strengthened copper alloys, which realize the simultaneous improvement of the conflicting mechanical and electrical properties.
10.1016-j.actamat.2021.117311	-1		Laser powder bed fusion (L-PBF) additive manufacturing was utilized to fabricate high-strength copper (Cu) alloys through inoculation of pure Cu powder with cobalt (Co) submicron particles. It was found that when the addition level of Co is lower than its maximum solid solubility in Cu (4.75 wt%), the microstructure of Cu-Co alloys is characterized by coarse columnar grains. Further addition of Co over 4.75 wt% led to a heterogeneous grain structure, with large equiaxed grains or columnar grains near the centers of melt pools whereas ultrafine equiaxed grains sitting on the melt pool boundaries. Microstructure characterization showed that the in-situ formed dual phase nanoparticles with Co shell and cobalt oxide (CoO) core acted as heterogeneous nucleation sites of Cu, which allowed ultrafine, equiaxed grains to form. The heterogeneously structured as-built Cu-Co alloy achieved a tensile strength of 381.4 +/- 2.9 MPa and an elongation of 31.6 +/- 1.3%. Co nanoprecipitation driven by post L-PBF heat treatment further increased the tensile strength of the Cu-Co alloy up to 491.1 +/- 12.6 MPa without notably sacrificing the ductility. The combination of high strength and high ductility distinguishes Cu-Co alloys from most conventionally and additively manufactured Cu alloys. This study shows a strategy to produce Cu alloys with high performance through remarkable grain refinement by heterogeneous nucleation.
10.1016-j.actamat.2021.117460	-1		Tuning stacking fault energy (SFE) via alloying provides a robust protocol to manipulate deformation mechanism and consequently the mechanical properties of metallic materials. Mechanical behaviours of materials with small dimensions have received significant attention due to the increasing requirement of the miniaturisation and the development of micro-electromechanical smart systems. However, the effects of SFE on the size-dependent plasticity have rarely been studied. Herein, we employed quantitative in-situ compression transmission electron microscopy to systematically uncover the size effects on the mechanical properties and deformation mechanisms of submicron-sized Cu-Al single-crystalline pillars. The SFE was controlled by adjusting the Al content in Cu-Al alloys. Our research found that the sample size effect on strength apparently decreased with reducing SFE or increasing Al content. A theoretical model was proposed to capture the size dependency of the strength by incorporating the effect of SFE on dislocation sources. Size-dependent work-hardening behaviour and deformation mechanism were comprehensively explored, which were controlled by the interplay among sample size, SFE and alloying induced short-range ordering. Lastly, a deformation map was constructed for submicron-sized Cu-Al alloys, which is directly correlated with mechanical properties .
10.1016-j.actamat.2021.117598	-1		Three possible twinning modes, Type I, Type II, and compound, as well as corresponding twin boundaries in 2H martensite of Cu 69.4 Ni 3.4 Al 27.2 single crystal, were studied by X-ray diffraction (XRD) and high-resolution transmission electron microscopy (HRTEM). The results are discussed with regard to the sharply different twinning stress or twin-boundary mobility. In self-accommodated martensite, all three modes not only coexist but are crystallographically coupled. The compound twin boundary is a coherent coplanar mirror plane with the smallest twinning shear. The Type II twin boundary is also a coherent strain-free interface. The high index rational approximation of Type II twin boundary was determined by trace analysis with the help of stereographic projection. The approximation is in good agreement with irrational indices calculated from elastic continuum. The Type I boundary is the most complex interface associated with high stress and high density of stacking faults inside the twin bands. Using HRTEM, two different stressed boundaries of Type I were confirmed. The intrinsic twinning mode in Cu-Ni-Al alloy is the compound twinning. In compression, the Type II twinning is the major deformation twinning mode. During deformation the Type I twins are eliminated, leaving Type II twinning bands with compound twins. The observed differences between the atomic structure of different twin boundaries can contribute significantly to the sharp differences in twinning stress.
10.1016-j.actamat.2022.117668	-1		In this work, the crystallization pathways and kinetics of the Cu47.5Zr45.1Al7.4 bulk metallic glass (BMG) are studied systematically using a broad collection of laboratory and synchrotron-based techniques, such as differential scanning calorimetry, transmission electron microscopy, in situ high-energy synchrotron X-ray diffraction (HEXRD), simultaneous small- and wide-angle X-ray scattering, and atom probe tomography. The crystallization sequence during heating at conventional slow rates and isothermal annealing near the glass transition temperature was determined to consist in preferential formation of (Cu, Al)(10)Zr-7 followed by the formation of CuZr2 and AlCu2Zr induced by long-range atomic diffusion. In situ HEXRD shows that the formation of the latter two phases is accompanied by the partial dissolution of the primary Cu-rich phase. Microstructural characterizations of annealed samples suggest that a new liquid phase with enhanced local order and obscure compositional changes has formed from the homogeneous supercooled liquid before crystallization. A concept analogous to the disorder-to-order transition in crystalline materials is applied here to describe the observed transition in liquid, resolving the longstanding apparent contradiction between observing a nanoscale phase separation versus a liquid-liquid phase transition during devitrification. Furthermore, we suggest that the formation of an intermediate liquid phase prior to crystallization is the structural origin of the rapid devitrification kinetics during the primary crystallization. On the basis of our combined experimental results, a scheme is proposed to generalize the complex multistep devitrification mechanisms of the Cu47.5Zr45.1Al7.4 BMG during isothermal annealing or slow heating. This work may provide new insights into the crystallization behavior and thermal stability of Cu-Zr-Al BMGs in terms of thermodynamics and kinetics and might lead to deeper understanding of the underlying mechanisms of the often observed rapid crystallization processes of deeply undercooled metallic liquids.
10.1016-j.actamat.2022.118059	13	clusters; atomic; glass; atoms; composition; dynamics; metallic; icosahedral; glasses; simulations; molecular; cu-zr; molecular dynamics; metallic glasses; structural	Alloys around eutectic points are thought to be good glass formers. However, the glass-forming ability (GFA) as a function of composition from pure metals to the eutectic alloy has not been quantified and the underlying microstructural and dynamical origins are unclear. In this work, the GFA of Cu-Ag alloys at various compositions was thoroughly investigated by using molecular dynamics simulations. According to the results, the critical cooling rate for glass formation Rc (K/s) varies with solute content x ' (at%), following R-c asymptotic to Aexp(kx') where A = 4.61 x 10( 12) and k =-0.25 on the Cu side and A = 4.43 x 10(12) and k =-0.19 on the Ag side. The R(c )of the eutectic alloy is about 5 orders of magnitude lower than that of the pure metals. Structurally, the number of densely packed icosahedral-like clusters in Cu-Ag metallic glasses increases with increasing solute content, resulting in the most densely packed structure at the eutectic composition. The dynamical properties of Cu-Ag melts are basically independent on composition at high temperatures, but obviously change with composition at low temperature. Besides the largest reduced glass transition temperature, the highest five-fold symmetry (FFS) local structure and more importantly the retarded dynamics of liquid atoms below the liquidus temperature around the eutectic composition impart the eutectic alloy with the best glass-forming ability.
10.1016-j.actamat.2022.118107	-1		The superelastic behavior of a Cu-Al-Be alloy was studied in situ during tensile tests combining two high-energy synchrotron techniques. The initial microstructure was reconstructed using diffraction contrast tomography; the elastic strain and stress tensors of each individual grain were then determined using a 3D X-ray diffraction microscopy technique. The alloy was heat-treated until coarse grains formed, and the probed volume fraction was limited to -200 grains. The mean grain size, as estimated from both techniques, agreed well with that determined by optical microscopy, i.e., approximately 130 mu m. During the early stage of the martensitic transformation (MT), 187 grains with strong stress heterogeneities were detected in the elastic domain; in particular, the stress values along the tensile direction varied by a factor of three between different grains. The reconstructed 3D microstructure served as input data for finite element modeling, wherein a micromechanical approach factoring in the martensitic transformation was used to simulate the in situ tensile tests. The coupled numerical and experimental tensors of the 187 grains confirmed strong stress heterogeneities between them. The influence of the position and crystallographic orientation of the neighboring grains were also examined.
10.1016-j.actamat.2022.118256	-1		Deformation induced grain boundary (GB) relaxation with resultant enhancements in thermal stability was observed in various metals with grain sizes below a critical size. In this study, effects of stacking fault energy (SFE) on the GB relaxation and thermal stability are investigated in several Cu-Ni and Cu-Al alloys with gradient nanograined samples prepared using the surface mechanical grinding treatment. For each alloy, thermal stability drops with a decreasing grain size from submicrometers to about 70 nm. However, two distinct grain size dependences of thermal stability were observed below 70 nm. For Cu-10Ni and Cu-5Ni alloys with higher SFEs than Cu, thermal stability increases for smaller grains, similar to that in pure Cu. For Cu-10Al and Cu-5Al with lower SFEs than Cu, as grain sizes decrease the thermal stability elevates firstly and then drops, exhibiting a stability peak at a certain size. The observed thermal stability in the Cu alloys below 70 nm can be attributed to the GB relaxation induced by plastic deformation dominated by partial dislocation activities. The different behaviors of GB relaxation in these Cu alloys demonstrated its obvious dependence on SFE, which determined the governing deformation mechanisms and hence the degree of relaxation of GBs.
10.1016-j.actamat.2022.118293	7	irradiation; shear; grain; ta; deformation; size; radiation; voids; nanocrystalline; simulations; similar; void; temperature; irradiated; boundaries	Helium is a common nuclear reaction product, and it plays an important role in radiation-induced void swelling. Although extensive studies have been conducted to investigate the helium effects in metals and alloys, most of them were based on the post-irradiation analyses or computer simulations. Conclusive evidence that can demonstrate how voids evolve in the presence of He under high-temperature radiation remains limited. In this work, we performed in situ heavy ion radiation studies in a transmission electron microscope to compare the radiation response of the preexisting nanovoids in single crystal copper sub-jected to a single beam of 1 MeV Kr ions and a sequential dual beam of 14 keV He ion and 1 MeV Kr ion at 350 degrees C. Our studies revealed that the nanovoids would contract continuously until being eliminated when irradiated by a single beam of Kr ions. In comparison, the nanovoids in helium-injected Cu could reach a stable state and eventually stopped shrinking. Moreover, the influence of helium on the kinetics of void/bubble evolution under heavy ion irradiation was discussed within the framework of a proposed critical bubble model and bubble coarsening model.
10.1016-j.actamat.2022.118368	-1		Manipulating coherent twin boundaries (CTBs) opens an avenue to design strong nanostructured ma-terials. However, below a critical TB spacing, these inherently defective CTBs decorated with kink -like steps (abbreviated by kinks) and intersected with grain boundaries (GBs) will suffer from the thermal/mechanical instability, leading to the degradation of material properties. Here, utilizing Cr-segregation at kinks and GBs via a minor (1 at%) Cr-doping, we report the nanocrystalline-nanotwinned (NNT) Cu-Cr alloy manifests continuous strengthening reaching 1.2 GPa at extremely fine TB spacing of similar to 2 nm, associated with excellent structural-mechanical stability after high-temperature (0.5Tm of Cu) an-nealing. The underlying mechanism mainly originates from the highly stabilized defective CTBs controlled by Cr-segregation at kinks and TB-GB junctions, which facilitates the plastic deformation mode transition: from detwinning dislocation nucleation to stacking faults (SFs) accumulation for ultrahigh strength . Un-der elevated temperature, the stabilized TBs inhibit GB motion and therefore result in enhanced thermal stability of NNT Cu-Cr alloys, which is quantitatively explained via a modified Zenner pinning model. Our findings not only deepen the understanding of deformation mechanisms in nanotwinned metals, but also provide a new perspective to design plainified Cu alloys with high performances.
10.1016-j.actamat.2022.118465	-1		Single crystalline materials have the potential to exhibit superior performance because they exclude grain boundaries, which increase susceptibility to creep, oxidation, and corrosion, and make thermal and electronic transport inefficient. However, single crystal properties vary significantly with crystallographic orientation, making the ability to control the orientation critical for their use in applications. The complex nature of crystal nucleation and growth processes makes such control challenging. Here we report a new crystal reorientation mechanism that results in abrupt and massive orientation changes in bulk single crystalline and oligocrystalline alloys via solid state thermal processing. We demonstrated this method in two alloy systems, FeMnAlNi and CuAlMn, and achieved repeated, massive orientation changes in the solid state. These findings offer a new strategy for manipulating the orientation of large single crystals on demand in order to take advantage of their superior and highly anisotropic properties.
10.1016-j.actamat.2022.118484	-1		Two types of alloys, Cu-Ni-Co-Si and Cu-Cr-Zr, are considered candidate materials for next-generation integrated circuits due to their superior comprehensive performance. However, the rapid development of these two types of alloys remains difficult using conventional simulation techniques. Machine learning offers a new tool for accelerating the design and discovery of new materials with required property profiles. Herein, composition -process-property database of the six-element Cu-Cr-Ni-Co-Si-Zr alloys were established, and a novel strategy of customized performance design for different application environments was proposed. Then, four alloys with different performance characteristics were rapidly screened from 850,500 candidates using a multi-property segmented screening method, and the predicted results agreed well with the experimental results. Impor-tantly, the developed Cu-1.0Cr-1.0Ni-2.5Co-0.8Si alloy was used as a bridge alloy to link the Cu-Ni-Co-Si and Cu-Cr-Zr alloys together, filling the gap in the mid-segment performance (220-240 HV, 45-65% IACS) of Cu-based alloys. Interestingly, the studied alloy was a dual-phase precipitation-strengthened alloy. It was found that the small spherical (Co, Ni)2Si phase was the main influence on the micro-hardness and strength, while the large rod -shaped Cr3Co5Si2 phase was the main reinforcing phase that affected ductility and electrical conductivity. The design method proposed in this paper accelerates the development of the Cu-Cr-Ni-Co-Si alloy system, which has great potential for application in integrated circuits and heat sinks.
10.1016-j.actamat.2022.118545	-1		Nanocrystalline metals attract intensive interests due to their high strength, excellent wear resistance and su-perior radiation. However, grain coarsening at elevated temperatures can lead to significant property degrada-tion, impairing their potentials for high temperature applications. Here, we report a unique interplay of immiscible Cu, Ag, Fe grains in stabilizing the grain structure and tailoring the texture development. The Cu50Ag50 alloy experiences drastic grain coarsening after annealing at 600 degrees C and 700 degrees C. In contrast, the Cu-Ag-Fe nanocomposites exhibit much smaller grain size upon annealing. Interestingly, while the Cu50Ag50 alloy displays random nanocrystal orientation, highly textured Cu-Ag-Fe nanocomposites form. Furthermore, the composition of Fe plays a dominant role in changing the texture of nanocomposites from (111) Ag (Cu) and (110) Fe in Cu45Ag45Fe10, to prominent (110) Ag (Cu) and (100) Fe in Cu33Ag33Fe34. The fundamental mechanisms behind the texture formation and evolution are discussed. This study provides a fresh perspective to the design of stable nanocomposites with tunable texture.
10.1016-j.actamat.2023.118964	7	irradiation; shear; grain; ta; deformation; size; radiation; voids; nanocrystalline; simulations; similar; void; temperature; irradiated; boundaries	In this work, we employ transmission electron microscopy and helium ion irradiation to study the interactions between the radiation-induced point defects and the incoherent/semi-coherent precipitates in CuCrZr and Cu-1Fe alloys. Both thin foil and bulk implantation were used to explore the interactions of radiation defects with interfaces. The irradiated defects show a strong interface character dependence in both implanted CuCrZr and Cu-1Fe alloys after similar level of radiation damage. Large-sized voids appear around the incoherent Cr precipitates, while no visible cavities are formed around precipitates in Cu-1Fe alloy. Interestingly, three types of semi-coherent Fe precipitates exhibit various irradiation damage mitigation mechanisms, such as twin bound-aries migration, short range elements redistribution and precipitate abnormal growth, which are caused by ra-diation defect-mediated dislocation glide, element diffusion and mass transportation. The high sink efficiency of the incoherent precipitates trap vacancies and leads to the generation of submicron-sized voids. In contrast, the semi-coherent precipitates can regulate the motion of point defects and effectively enhance the recombination rate of vacancies and interstitials.
10.1016-j.actamat.2023.119468	-1		Direct-current (DC) Electrodeposited nanotwinned copper (nt-Cu) is a promising candidate for interconnection materials in integrated circuit for its excellent mechanical, electrical and thermal properties. However, the formation mechanism of nanotwins during DC electrodeposition of nt-Cu remains unclear. In this study, a two-dimensional nucleation and growth model of nt-Cu is established. The critical nucleation size and average twin spacing were evaluated theoretically. The results demonstrate a relatively high probability of twin nucleation through random stacking with the average twin spacing derived to be only similar to 1 nm. The gap between theoretical and observed twinning probability can be ascribed to the surface migration-induced dissipation of nuclei. Molecular dynamics simulation further confirms the formation and subsequent dissipation of nuclei during deposition of Cu. By providing a clear illustration of nanotwin formation process, this study contributes to the understanding of nt-Cu electrodeposition.
10.1016-j.actamat.2023.119476	7	irradiation; shear; grain; ta; deformation; size; radiation; voids; nanocrystalline; simulations; similar; void; temperature; irradiated; boundaries	This work presents characterization of thermo-mechanically stable, bulk nanocrystalline (NC) Cu-Ta alloys under a combination of extreme states using high-temperature, dynamic tensile extrusion experiments. The NC Cu-Ta was subjected to high dynamic strain rates up to 10(5)/s, large plastic strains of 100-500 %, and high homologous temperatures greater than 50 %TM. This combination of thermo-mechanical conditions provides a unique look at how these extremely stable microstructures can accommodate and reconfigure under situations where dislocation activity is the most extreme, given constitutive relationships between strain rate, dislocation nucleation, and plastic work. Elevated temperature tests results reveal NC Cu-1Ta alloys are capable of forming a coherent jet, (25 mm in length by 1.8 mm in diameter) as it accelerates out of the die after being dynamically extruded. Microstructural analysis reveals that unlike previous reports on conventional un-stabilized nano or near nano-grained Cu, NC Cu-Ta alloys behave differently. They do not undergo grain coarsening via a nucleation and growth process, but rather behave identically to that of coarse-grained Cu. The NC grains elongate along the extrusion direction and at the same time shrink in diameter and develop a <111> type texture. Ultimately, the occurrence of premature dynamic failure was attributed to the inherent constraints posed by processing defects during synthesis.
10.1016-j.actamat.2023.119487	-1		The physics of metallic glass local devitrification employing ultrafast laser irradiation is the cradle of complex phenomena that are still not understood despite its applicative potential in material processing for nanotechnology. This paper reports a theoretical simulation combining the two temperature model and classical molecular dynamics simulations to unravel the mechanisms that lead to the localized phase transition in Cu-Zr metallic glass. According to observations, the initial composition of amorphous samples plays an essential role, in addition to nonequilibrium thermodynamic processes caused by the laser energy deposition that alters the atomic environment. We further demonstrate that specific compositions devitrify despite its high glass-forming ability. The thermodynamic conditions fostering the emergence of a stable nanocrystalline phase are clearly established. The compressive pressure wave and the rapid heating process caused by ultrafast laser energy deposition synergistically contribute to disrupt the microstructure of the glass significantly, thereby initiating the devitrification process. Results are discussed using additional classical MD simulations that provide valuable insights for interpreting the distinct contributions of temperature and pressure to the phase transformation. Finally, the impact of the formed nanocrystals on the phononic thermal conductivity of the alloy is presented confirming the potential application of the laser-induced devitrification process for the development of a new generation of nanoarchitectured materials.
10.1016-j.actamat.2023.119531	-1		Recent investigations have indicated that compositional heterogeneity, which is compositional undulation of alloying elements in single-phase solid solutions, can enhance the strength without sacrificing ductility, similar to cluster strengthening, of single-crystal nano-pillars and bulk nanocrystalline metallic materials. However, the impact of compositional heterogeneity on the mechanical properties of coarse-grained metallic materials is not yet fully understood. In this study, we examine the influence of compositional heterogeneity on the tensile mechanical properties of a Cu-9Al (at%) alloy with a coarse-grained structure fabricated using wire arc additive manufacturing and with an ultrafine-grained structure after further processing. Our results demonstrate that the effects of compositional heterogeneity depend significantly on the grain size. Specifically, in ultrafine-grained samples, there is a remarkable improvement in strength with only a slight reduction in ductility. However, as grain size increases, the strengthening effect of compositional heterogeneity diminishes, resulting in softening with a significant loss of ductility. These phenomena can be attributed to the behaviour of dislocations in the materials. Overall, this study highlights the importance of understanding the relationship between compositional heterogeneity, grain size, and mechanical properties in metallic materials, which can inform the design of new materials with improved strength and ductility.
10.1016-j.actamat.2023.119547	-1		The wider application of copper alloys is challenged due to their relatively low strength and thermal stability. Here we report a nano-reinforcement dispersion strategy to achieved an excellent combination of ultrahigh strength, good ductility, high thermal stability and high thermal conductivity in a hierarchical nanostructured copper-tungsten (Cu-W) immiscible alloy. Our strategy relied on a uniform dispersion of nanoscale W particles (average size similar to 7.6 nm) in ultrafine-grained Cu matrix (similar to 0.48 mu m), by employing a molecular-level sol-gel synthesis and followed two-step reduction at low-temperature. The nanostructured Cu-W alloys exhibit a high tensile strength of 709 MPa, a total elongation of 20 % and a high thermal conductivity of 370 Wm(-1)K(-1) at room temperature. The Cu-W alloy also has excellent thermal stability and the grain size hardly changes even after annealing at 800 degrees C for 1 h . Additionally, the nanostructured Cu-W alloy with numerous interfaces shows the potential to offer superior irradiation resistance. This work provides an effective strategy for constructing high-performance nanostructured immiscible alloys.
10.1016-j.actamat.2023.119550	-1		The paper presents a full-field strain analysis of the appearance/disappearance of twinned martensite in a Cu- Al-Ni single crystal subjected to thermal cycles. Localized Spectrum Analysis (LSA) was employed to process images of a checkerboard pattern preprinted on the sample's surface, enabling us to obtain strain maps with a suitable trade-off between strain resolution (2 x 10-4) and spatial resolution (0.26 mm). During the cooling of the initially austenitic sample, habit plane variants (HPVs) were identified from the in-plane components of their mean right strain tensor. The match between measured data and theoretical expectations enabled us to measure the stretch parameters associated with the cubic-to-orthorhombic transformation occurring in the material. Various deformation mechanisms were revealed by an analysis in the strain space. In particular, the process of martensite appearance during cooling appeared to be based on the coordinated activation of HPVs pairs whose strain levels globally compensate each other. Elastic strain gradients were also evidenced, highlighting the need for additional deformation to achieve kinematic compatibility at microstructure interfaces. Lastly, several thermal cycles were applied to the previously-trained sample, enabling us to quantify the level of spatio-temporal repeatability of the phase transformation.
10.1016-j.actamat.2023.119600	-1		Stress fields arising from triple junction disclinations (TJDs) play a significant role in the microstructure evolution during the plastic deformation of metals. The calculation of TJD strengths from grain orientation data was developed by Bollmann more than 50 years ago, but so far applied only to collections of a few grains. Developed here is a new methodology for calculating TJD strengths and the associated stress fields in large polycrystalline assemblies using experimental electron back-scattered diffraction (EBSD) maps. The methodology combines Bollmann's approach with a representation of materials as cell complexes. It is computationally efficient and allows for obtaining the spatial distribution of TJD strengths from EBSD images containing thousands of grains. Analysed are the fraction, distribution, and strengths of TJDs within statistically representative microstructures of Cu-0.4%Mg alloy subjected to severe plastic deformation (SPD) by equal channel angular pressing. It is shown that the formation of low-angle grain boundaries (dislocation walls) during SPD leads to an increasing number of TJDs, whose spatial distribution is progressively more uniform and whose strength distribution remains nearly constant. This result suggests that the SPD reduces the internal stresses associated with disclinations in large regions of the material, as closely situated disclinations screen each other's fields. Regions with high local stresses can be expected between sparsely distributed TJDs with the highest strengths. The average distance between such TJDs could be considered as a natural length scale in a material.
10.1016-j.actamat.2023.119624	13	clusters; atomic; glass; atoms; composition; dynamics; metallic; icosahedral; glasses; simulations; molecular; cu-zr; molecular dynamics; metallic glasses; structural	The atomic structures of Cu-Zr alloys have been extensively studied due to the unusually high glass forming ability of this system. In this work, we investigate the nearest-neighbor atomic structures of several simulated disordered Cu-Zr compositions at three temperatures: 1450 K (liquid), 700 K (undercooled liquid), and 350 K (disordered solid). The results show that over 90 % of the local structures in these systems can be described by one of 12 building-block atomic cluster geometries, regardless of composition or temperature, and that these structures all exhibit icosahedral or quasi-icosahedral geometries. Most of the building-blocks are unique in their combination of representative Voronoi polyhedron geometry, predominant central atom type, and occupation probability for each site in the cluster. In addition to the 12 common building-blocks, 35 outlier structures unique to their simulated compositions and temperatures were observed. The outliers were primarily nonicosahedral. While the populations of the common building-blocks do not exhibit clear trends with temperature or composition, the overall population of outliers increased with decreasing temperature, suggestive of their role in accommodating the lack of translational order in the disordered solid.
10.1016-j.actamat.2024.119680	-1		Solid solution and long-range atomic order hardening represent two well-known strategies for increasing strength of bulk metallic materials. Here, we observed the opposite trends in mechanical behavior of defect-lean nanoparticles of Cu-Au alloys fabricated by solid state dewetting of Cu-Au bilayers deposited on sapphire substrate. In the fully disordered state, the nanoparticles of Cu3Au alloy exhibited the highest compressive strength reaching staggering 41 GPa for the smallest studied particles, followed by nanoparticles of pure Cu, and of CuAu alloy. Thus, taking pure Cu and Au nanoparticles as a reference, both solid solution hardening (Cu3Au) and solid solution softening (CuAu) were observed in nanoscale plasticity of the Cu-Au system. Additional annealings at the temperature of 350 degrees C, 40 degrees C below the critical point of A1-L1(2) transformation, were performed to induce different degrees of the long-range order in the Cu3Au nanoparticles. It was shown that the strength of fully ordered Cu3Au nanoparticles is very similar to that of their fully disordered counterparts, whereas the partially ordered Cu3Au nanoparticles larger than 500 nm in size exhibited a significant drop in strength . No effect of long-range order on compressive strength of smaller nanoparticles was observed. These findings were discussed in terms of plasticity mechanisms controlled by nucleation of new dislocations. Specifically, it was proposed that the presence of oxidation-induced Au-rich subsurface layer in the Cu3Au nanoparticles is responsible for their ultrahigh strength .
10.1016-j.actamat.2024.119827	7	irradiation; shear; grain; ta; deformation; size; radiation; voids; nanocrystalline; simulations; similar; void; temperature; irradiated; boundaries	The strengthening effect of interface in materials is usually studied by monitoring the change of strength in response to varying structure sizes, such as the varying grain or phase sizes. In this study, we demonstrate that the strength of a nanostructured material can be recoverably tuned by modifying interfacial structure without changing structure size. Specifically, we studied the Cu/Ag spinodoid alloys fabricated by dealloying and electrochemical deposition, which exhibit a cube -on -cube orientation relationship between two interpenetrating nanophases. This material remains stable against coarsening even at temperatures near the eutectic melting point, due to the presence of low -energy semi -coherent interfaces and the lack of defects such as grain boundaries. Using cyclic thermal annealing, we are able to alter the solid solubility of both nanophases and, consequently, the lattice mismatch between them, resulting in a recoverable tuning of hardness and strength . The amplitude of hardness modulation decreases with increasing feature size (A), and changes sign when A exceeds similar to 500 nm. This is attributed to a competition between two strengthening mechanisms: the interfaceinduced strengthening that is more prominent at a lower A, and the solid solution hardening that is largely A -insensitive. The finding indicates that interface hardening prevails over solution hardening when A is below similar to 500 nm. Current study paves the way for the development of strong and stable nanostructured materials whose properties can be optimized by independently tailoring feature sizes and interfacial structures.
10.1016-j.actamat.2024.119874	-1		Precipitation hardening is a well-known phenomenon which is widely harnessed in alloy design strategy. In particular, the microstructural features such as shape, size, precipitate number density and volume fraction determine the mechanical behaviour of materials. During service, the morphology of precipitates sometimes achieves a complex 3D shape upon displaying branching and/or splitting patterns. Unfortunately, the detailed information about this intricate morphology cannot be retrieved through traditional experimental techniques based on 2D visualization. Here, we report the implementation of a 3D analysis technique combining Focused Ion Beam (FIB) and Scanning Electron Microscopy (SEM) tomography to visualize the atypical petal-like morphology of Fe-rich precipitates in a Cu-Fe alloy. Using Phase-Field modelling (PFM), we identify the mechanism responsible for the unusual morphologies of Fe-rich particles. Our work highlights the significance of 3D characterization of precipitates and provides a fascinating pathway for refining understanding of precipitation mechanisms in metals and alloys.
10.1016-j.actamat.2024.120163	-1		Nano-lamellar structured Cu-0.1 at% Zr alloys are prepared by the combination of equal channel angular pressing and subsequent cryogenic rolling. The advanced processing route enables a systematic reduction of the lamellae boundary spacing down to 45 nm and a concurrent increase of yield strength up to 626 MPa. Subsequent annealing at temperatures up to 673 K induced recovery processes and uniform coarsening through triple junction motion, avoiding a catastrophic degradation of the microstructure and performance and preserving the yield strength at a level comparable to ultrafine-grained copper. Simultaneously, the tensile uniform elongation experienced a substantial recovery up to 11.9 %. The high thermal stability is mainly attributed to the low mobility of grain boundary and the relaxation of non-equilibrium grain boundaries, both of which are facilitated by the microalloying of Cu with Zr. Based on the theory of dislocation pile-up at boundaries, the Hall-Petch equation is adopted and extended to the lamellar structured Cu-0.1 at% Zr alloy, revealing a lower-critical bound of 90 nm for lamellae boundary spacing, corresponding to an effective boundary spacing of about 150 nm.
10.1016-j.actamat.2024.120235	-1		Ultra-hard and wear-resistant metallic alloys are crucial for engineering applications to withstand prolonged wear and tear. However, fabricating multiple component alloys with varying hardness levels poses challenges in compositional design, processing optimization, and the application of hardening techniques across different alloy systems. Here, we demonstrate a facile approach for fabricating ultrahard FeMnAl(Cu) low-density medium entropy alloys (MEAs) with flexible hardness by inducing the precipitation of beta-Mn via a routine aging process. This method enables a broad range of tunable hardness, from relatively soft (210 HV) to ultrahard (1042 HV), by controlling the precipitation of beta-Mn in FeMnAl(Cu) low-density MEAs within a few hours of aging. The rapid aging-induced hardening response endowed these FeMnAl(Cu) MEAs with exceptional resistance to wear damage. These findings pave a new way for developing ultrahard and wear-resistant metallic alloys, which eliminates the complex and costly composition design and thermalmechanical processing routes typically required to harden conventional steels and alloys.
10.1016-j.actamat.2024.120519	-1		The Cu-Ni system is a typical dissolutive system due to its mutual dissolution across a wide range of temperatures and compositions. We characterized the effects of Ni dissolution on the wetting behavior of liquid Cu by combining high-temperature wetting experiments, in-situ observation of spreading and solidification, microstructure analysis of the quenched droplets, and computational fluid dynamic (CFD) simulations. In the very early moment, at 1100 degrees C, when the Cu droplet is brought in contact with the Ni substrate, it oscillates due to capillarity and is dampened by inertial effects, while the significant Ni dissolution at 1150 degrees C largely reduced the initial oscillations. Later, a peculiar spreading behavior is observed and we propose to describe it through a 4step mechanism: pinning of the contact line by a newly formed solid solution layer at the interface acting as a physical barrier, driving of liquid towards the solidified edge due to a Ni-concentration induced Marangoni flow, forming of a precursor film ahead of the solidified edge caused by the strong Cu-Ni interactions and Marangoni flow, and finally depinning due to overflow as a result of liquid accumulation at the solidified edge. The formation of a solid solution layer is confirmed by in-situ observation and quenching. The Ni-concentration induced Marangoni flow is characterized experimentally and further investigated by CFD simulations. The proposed step flow mechanism can be potentially relevant to other dissolutive wetting systems (e.g. Bi/Sn, Ag/Cu and Cu/Fe systems), which are crucial for high-temperature processing techniques.
10.1016-j.actamat.2024.120589	-1		Developing bimetallic interfaces with high interfacial bonding strength is important for metallic composites used under harsh service conditions. However, the formation of brittle intermetallic compounds is unavoidable for some interface combinations, resulting in a significant deterioration of bonding strength . In this work, we demonstrate the development of a Cu alloy/Al alloy interface with a shear strength of 126 +/- 15 MPa-a value almost twice that reported in previous studies. The exceptional interfacial bonding strength is attributed to a special interface structure, composed of brittle intermetallic compound layers connected internally by dowels of a metastable Cu2Al3 phase, achieved via alloy design and process control. During solid-liquid composite processing, a liquid diffusion layer forms at the interface between the Cu and Al alloys. A precursor Cu4Al7Ni phase then develops at the Cu side and transforms into a metastable Cu2Al3 phase with a banded structure. Finally, layers of Cu9Al4 and CuAl2 layers form, which are fully connected to the Cu2Al3 phase. The banded arrangement of the Cu2Al3 phase acts to block crack propagation and deflect cracks into the eutectic layer and Al alloy, resulting in an ultra-high interfacial bonding strength . This work demonstrates that high interfacial bonding strength can be achieved by tailoring the interface structure instead of by decreasing the interface thickness, and thus paves a new way for developing high-performance bimetallic interfaces.
10.1016-j.actamat.2025.120714	-1		Long-range interactions and correlations are distinctive attributes of non-equilibrium processes. A suitable tool for studying long-range interactions in polycrystalline materials is the orientation correlation function. It was introduced as early as 1965 using the concept of mesotexture which incorporates information about grain orientations and geometries. However, its application has been limited because most materials' characterisation works are still focused on conventional texture analysis. More recent studies proved that grain-grain interactions were independent of grain size, but did not go further to consider the longer-range interactions on structure development. The present study uses a novel discrete methodology for reconstruction and analysis of polycrystalline structures obtained by EBSD microscopy that allows for the first time to reveal and quantify the long-range effects on structure evolution of severely deformed Cu-0.1%Cr-0.1%Zr, Cu-0.1%Cr-0.1%Zr-0.05%Y, Cu-0.3%Cr-0.5%Zr and Cu-0.25%Mg (wt%) alloys. It is shown that the first- and second-order grain neighbours in all considered alloys obey scale-invariant power-law dependence as revealed in the previous studies with the first-order grain neighbours. However, our results show that the scale invariance extends much farther, between the fourth and seventh grain neighbours, depending on the material and accumulated plastic strain. These results cannot be explained by the conventional size effect reasoning discussed in previous publications. They suggest that the material discreteness, in the sense of numbers rather than sizes of grains, is the origin of the observed long-range correlations and the emergence of mesostructure that breaks the scale invariance.
10.1016-j.actamat.2025.120772	14	strength; properties; conductivity; electrical; mechanical; cu-; grain; mpa; electrical conductivity; aging; precipitation; phase; mechanical properties; tensile; phases	The mechanical strength of sintered nanoparticles (NPs) limits their application in advanced electronics packaging. In this study, we explore the anisotropy in the microstructure and mechanical properties of sintered copper (Cu) NPs by combining experimental techniques with molecular dynamics (MD) simulations. We establish a clear relationship between processing conditions, microstructural evolution, and resulting properties in pressure-assisted sintering of Cu NPs. Our findings reveal that pressure-assisted sintering induces significant anisotropy in the microstructure, as evidenced by variations in areal relative density and the orientation distribution of necks formed during sintering. Specifically, along the direction of applied pressure, the microstructure exhibits reduced variation in areal relative density and a higher prevalence of necks with favorable orientations. The resulting anisotropic mechanical properties, with significantly higher strength along the pressure direction compared to other directions, are demonstrated through micro-cantilever bending tests and tensile simulations. This anisotropy is further explained by the combined effects of strain localization (influenced by areal relative density) and the failure modes of necks (determined by their orientation relative to the loading direction). This work provides valuable insights into the analysis of sintered NPs microstructures and offers guidance for optimizing the sintering process.
10.1016-j.actamat.2025.121035	12	thermodynamic; ternary; phase; data; experimental; equilibria; phase equilibria; liquid; binary; experimental data; calculated; phases; literature; model; calphad	Recently elaborated tracer-interdiffusion couple approach is used to quantify the differences of atomic mobilities measured in homogeneous alloys with purely entropic driving forces and those determined from diffusion couples under chemical gradients. First, the self-diffusion rates of Fe, Ni and Cu are measured in selected homogeneous alloys of the ternary Cu-Fe-Ni system at 1273 K using the radiotracer method. Following, a novel augmented tracer-interdiffusion couple approach is used with the Cu50Ni50 and Fe50Ni50 binary alloys as end-members and depositing the 55Fe and 63Ni radioisotopes at the initial contact plane and at the both external surfaces. The non-equilibrium vacancies are found to enhance the atomic mobilities at 1273 K in the Cu-Fe-Ni system by about 20%. The results confirm a high level of reliability and the reproducibility of the approach for producing highly accurate diffusion data for generating mobility databases. Together with a CALPHAD-like theoretical analysis and thermodynamic factors, these results present a complete data set for the quantitative verification of the theoretical description of diffusion in ternary alloys. The impact of vacancy production on the developed chemical profiles and the Kirkendall effect are analyzed. An agreement between the experimental findings and the theoretical predictions is shown.
10.1016-j.actamat.2025.121054	-1		The successive stress-induced phase transformations in single-crystal Cu-Al-Mn alloys, which exhibit excellent superelasticity and ductility, were investigated using electron microscopy and synchrotron X-ray diffraction. In a Cu-16.8Al-9.6Mn (at%) alloy, which is in the martensitic phase at room temperature, a stress-induced martensitic transformation from a 6M-type stacking structure to a 2M-type stacking structure was revealed. At the 6M and 2M interface, it was observed that structural changes progress with partial dislocations running every three layers within the 6M structure. A Cu-17Al-11Mn (at%) alloy, which is in the parent L21 phase at room temperature and exhibits superelasticity, undergoes a successive stress-induced phase transformation of L21 -> 6M -> 2M, resulting in a shape recovery exceeding 16 % in strain. The 6M -> 2M transformation leads to an expansion of the stress-strain hysteresis loop, thereby enhancing the energy dissipation capability. The microstructure observations suggest that deformation in the 2M phase and the complex form of the reverse transformation contribute to the energy dissipation.
10.1016-j.actamat.2025.121342	14	strength; properties; conductivity; electrical; mechanical; cu-; grain; mpa; electrical conductivity; aging; precipitation; phase; mechanical properties; tensile; phases	This study reports a novel observation of room-temperature electrochemical dealloying in binary Cu-Fe laser cladding layers with less noble element (Fe) content far below the FCC percolation threshold (20 %). Through systematic investigation of microstructure and dealloying behavior of laser-cladded Cu-16 wt% Fe (named 16Fe), we reveal that Fe nanoparticles with an average size of 4.1 nm were embedded in the Cu-rich matrix, enabling formation of interconnected nanochannels during dealloying despite the Fe content being below 20 %. Experimental results demonstrate that the parting limit of the Cu-rich matrix is approximately 8.1-10.9 at%. Three-dimensional percolation simulations prove that the Fe nanoparticles reduce the percolation threshold of FCC solid solution, with solid-solved Fe atoms acting as bridges in the Cu-rich phase to facilitate the connection of Fe nanoparticles. During dealloying, the nanoporous structure exhibited no significant coarsening, leading to the formation of network-like nanochannels rather than the typical ligament-porous morphology. This work provides insights into designing nanoporous materials using alloys with low less-noble-element content.
10.1016-j.actamat.2025.121373	14	strength; properties; conductivity; electrical; mechanical; cu-; grain; mpa; electrical conductivity; aging; precipitation; phase; mechanical properties; tensile; phases	Copper (Cu) is essential to the electrification of society, yet primary Cu ores contain less than 1% metal, making mining insufficient to meet the demands of the clean energy transition. Recycling offers a viable alternative, reducing CO2 emissions by up to 65%, but conductivity losses due to scrap-related impurities hinder its application in high-performance systems. In this work, we introduce a recycling strategy for Cu recovered from electric vehicle (EV) batteries, enabling direct and circular reuse. Through nanoscale analysis, we show that by gettering impurities into nanoparticles spaced approximately 40 nm apart, they become effectively invisible to conduction electrons. This self-cleaning mechanism maintains both electrical conductivity and mechanical integrity, turning detrimental impurities into functional alloying elements and facilitating the sustainable reuse of Cu.
10.1016-j.actamat.2025.121601	-1		Medium voltage vacuum interrupters are high-performance current interruption devices in the contemporary energy transition and electrification. The current interruption performance is directly correlated to the properties of their electrical contacts made of Cu-Cr alloys. Therefore, enhancing their performance to respond to the continuously increasing demand for higher current, higher power, and high voltage applications inherently requires the optimization of the microstructure of the Cu-Cr alloys to increase their electrical and thermal conductivity. Herein, we unveil the microstructural features governing the effective thermal conductivity of Cu-25Cr sintered composites, a subject of much less scientific attention than their electrical conductivity due to the complex microstructure-thermal conduction relationships. We coupled advanced 3D characterization techniques, namely X-ray computed tomography and atom probe tomography, with experimental and full-field numerical investigation of the effective thermal conductivity for three Cu-25Cr sintered composites having different final relative density (94, 96, and 98%). We demonstrate the synergistic effect of solid solution, interfacial thermal resistance, phase distribution on the effective thermal conductivity. Interfacial pores hinder the thermal conduction across phases. The effective thermal conductivity also decreases due to elements in solid-solution that diffused in the Cu matrix during sintering, along with interfacial thermal resistance across Cu/Cr phases. Using a full-field numerical approach, we unravel a microstructure heterogeneity-induced heat flux anisotropy contributing to the anisotropy in effective thermal conductivity.
10.1016-j.actbio.2009.06.027	2	corrosion; surface; film; electrochemical; films; spectroscopy; layer; current; solution; potential; resistance; composition; x-ray; ions; showed	Cu-Al-Ni shape memory alloys (SMAs) have been investigated as materials for medical devices, but their biomedical application is still limited. The aim of this work was to compare the microstructure, corrosion and cytotoxicity in vitro of a Cu-Al-Ni SMA. Rapidly solidified (RS) thin ribbons, manufactured via melt spinning, were used for the tests. The control alloy was a permanent mould casting of the same composition, but without shape memory effect. The results show that RS ribbons are significantly more resistant to corrosion compared with the control alloy, as judged by the lesser release of Cu and Ni into the conditioning medium. These results correlate with the finding that RS ribbons were not cytotoxic to L929 mouse fibroblasts and rat thymocytes. In addition, the RS ribbon conditioning medium inhibited cellular proliferation and IL-2 production by activated rat splenocytes to a much lesser extent. The inhibitory effects were almost completely abolished by conditioning the RS ribbons in culture medium for 4 weeks. Microstructural analysis showed that RS ribbons are martensitic, with boron particles as a minor phase. In contrast, the control Cu-Al-Ni alloy had a complex multiphase microstructure. Examination of the alloy surfaces after conditioning by energy dispersive X-ray and Auger electron spectroscopy showed the formation of Cu and Al oxide layers and confirmed that the metals in RS ribbons are less susceptible to oxidation and corrosion compared with the control alloy. In conclusion, these results suggest that rapid solidification significantly improves the corrosion stability and biocompatibility in vitro of Cu-Al-Ni SMA ribbons.
10.1016-j.actbio.2021.04.037	-1		Copper intrauterine device is one of the most adopted contraceptive methods with high effectiveness (over 99 %), low cost, spontaneous reversibility and long-lasting usage. However, the side effects induced from the initial burst release of copper ions (Cu2+) hinder the continuation of the Cu-IUD made of Coarse-Grained Copper (CG Cu). We proposed to tailor the bio-corrosion behaviors of better control of Cu2+ release via the addition of bioactive Mg into the Ultra-Fine Grained (UFG) Bulk Cu. Thus, UFG bulk Cu with 0.4 wt% Mg was produced via equal-channel angular pressing. The microstructures of the UFG Cu-0.4Mg was observed using electron backscatter diffraction and transmission electron microscopy techniques. The in vitro long-term corrosion behaviors in simulated uterine fluid, cytotoxicity to four cell lines, in vivo biocompatibility and contraceptive efficacy were all studied on CG Cu, UFG Cu and UFG Cu-0.4Mg materials. The results demonstrate that both the ultrafine grains and the addition of bioactive Mg into Cu contribute to the suppression of the burst release of Cu2+ in the initial stage and the maintenance of high level Cu2+ in long-term release. Moreover, the UFG Cu-0.4Mg also exhibited much improved cell and tissue biocompatibility from both the in vitro and in vivo evaluations. Therefore, the contraceptive efficacy of UFG Cu-0.4Mg is still maintained as high as the CG Cu and UFG Cu while the side effects are significantly eased, suggesting the high potential of the UFG Cu-0.4Mg alloy as a new upgrading or alternative material for Cu-IUD. Statement of significance The side effects from burst release of Cu2+ at the initial implantation stage of Cu-containing intrauterine devices (Cu-IUD) is one of the main drawbacks of these devices. In this work, an ultra-fine-grained Cu (UFG Cu) alloyed with a low amount of bioactive Mg was used for a Cu-IUD. The UFG Cu-0.4Mg alloy exhibited suppressed burst release of Cu2+ at initial implantation, while active Cu2+ release for long-term usage was maintained, comparable to coarse-grained pure Cu. Furthermore, the UFG Cu-0.4Mg alloy displayed significantly improved biocompatibility with human uterus cells and a much decreased inflammatory response within the uterus. Therefore, the side effects from Cu-IUD were eased, while high antifertility efficacy of the UFG Cu-0.4Mg alloy was maintained. The UFG Cu-0.4Mg alloy is promising for Cu-IUD.
10.1016-j.actbio.2021.11.006	2	corrosion; surface; film; electrochemical; films; spectroscopy; layer; current; solution; potential; resistance; composition; x-ray; ions; showed	The existing adverse effects of copper in copper-containing intrauterine devices (Cu-IUDs) have raised concerns regarding their use. These adverse effects include burst release of cupric ions (Cu2+) at the initial stage and an increasingly rough surface of the Cu-IUDs. In this study, we investigated the use of two copper alloys, Cu-38 Zn and H62 as the new upgrading or alternative material for IUDs. Their corrosive properties were studied in simulated uterine fluid (SUF) by using electrochemical methods, with pure Cu as a control. We studied the in vitro long-term corrosion behaviors in SUF, cytotoxicity to uterine cells (human endometrial epithelial cells and human endometrial stromal cells), in vivo biocompatibility and contraceptive efficacy of pure Cu, H62, and Cu-38 Zn. In the first month, the burst release rate of Cu2+ in the Cu-38 Zn group was significantly lower than those in the pure Cu and H62 groups. The in vitro cytocompatibility Cu-38 Zn was better than that of pure Cu and H62. Moreover, Cu-38 Zn showed improved tissue biocompatibility in vivo experiments. Therefore, the contraceptive efficacy of the Cu-38 Zn is still maintained as high as the pure Cu while the adverse effects are significantly eased, suggesting that Cu-38 Zn can be a suitable potential candidate material for IUDs. Statement of significance The existing adverse effects associated with the intrinsic properties of copper-materials for copper-containing intrauterine devices (Cu-IUD) are of concern in their employment. Such as, burst release of cupric ions (Cu2+) at the initial stage and an increasingly rough surface of the Cu-IUD. In this work, Cu alloyed with a high amount of bioactive Zn was used for a Cu-IUD. The Cu-38 Zn alloy exhibited reduced burst release of Cu2+ within the first month compared with the pure Cu and H62. Furthermore, the Cu-38 Zn alloy displayed significantly improved biocompatibility and a much smoother surface. Therefore, high antifertility efficacy of the Cu-38 Zn alloy was well maintained, while the adverse effects are significantly eased, suggesting that the Cu-38 Zn alloy is promising for a Cu-IUD.
10.1016-j.actbio.2024.09.022	2	corrosion; surface; film; electrochemical; films; spectroscopy; layer; current; solution; potential; resistance; composition; x-ray; ions; showed	Copper-containing intrauterine devices (Cu-IUD) are adopted by worldwide women for contraception with the advantages of long-term effectiveness, reversibility and affordability. However, adverse effects occur in the initial implantation stage of Cu-IUD in uterine because of the burst release of Cu2 + . To minimize the burst release, in this study, we designed a series of Cu-Fe alloys with 0.5 wt%, 1 wt% and 5 wt% Fe and also further produced ultrafine grained (UFG) structure for these alloys via equal-channel angular pressing. The microstructures and properties of the coarse grained (CG) Cu, CG Cu-Fe alloys and UFG Cu-Fe alloys were systematically investigated, including grain structure and phase compositions, metallic ions release behavior, electrochemical corrosion performance, and in vitro cytotoxicity. With careful comparison and selection, we chose the CG Cu-5Fe and UFG Cu-5Fe for in vivo tests using rat model, including tissue biocompatibility, in vivo corrosion behavior, and contraceptive effectiveness. Moreover, the corrosion mechanism of the Cu-5Fe alloy and its improved biocompatibility was discussed. Both CG and UFG Cu-5Fe alloys exhibited dramatic suppression of Cu2 + release in simulated uterine fluid for the long-term immersion process. The in vivo tissue compatibility was significantly improved with both CG and UFG Cu-5Fe alloys implanted in the rats' uterine while the high contraceptive efficacy was well maintained. Due to the superior biocompatibility, the CG and UFG Cu-5Fe alloys can be the promising candidate material for Cu-IUD.
10.1016-j.addma.2016.04.003	-1		The Cu-based shape-memory alloy 81.95Cu-11.85Al-3.2Ni-3Mn (wt%) was processed by selective laser melting (SLM) and the parameters were optimised to obtain compact, fully martensitic samples with a high relative density of up to 99%. Next to the energy dissipated in the material, the scanning strategy was varied and an additional remelting step was applied. The influence of the different processing parameters on the overall density, the defect distribution as well as the grain sizes was then analysed. The processing technique has a strong influence on the degree of porosity and the distribution of the pores, the grain size as well as the grain morphology. SLM thus allows the targeted manipulation of microstructures during manufacturing. Simultaneously, this work stresses the importance of establishing the proper processing parameters for producing high-quality samples.
10.1016-j.addma.2020.101196	-1		In-situ uniaxial tensile tests coupled with X-ray computed tomography (XCT) were carried out on a Cu-4.3Sn alloy fabricated by selective laser melting. XCT models were constructed to enable step-by-step visualization of pore growth during deformation. Evolution of pores (mean diameter, density, volume fraction and sphericity) was quantified as a function of plastic strain. Evolution of the largest 7 pores existing in the as-printed part are individually characterized and coalescence is graphically presented. Results show that macroscopic instability begins once the largest internal pores reach the surface. Also, accelerated growth and coalescence of the largest 50 pores leads to rapid localization of strain followed by fracture. Pore growth was modeled using the Rice-Tracey (RT) and Huang models for different populations of pores and the parameters were optimized. The RT and Huang constants were found to depend on the initial mean pore diameter.
10.1016-j.addma.2020.101411	-1		Cu-10Sn (wt. %) alloy specimens were prepared by Laser-Powder-Bed-Fusion based Additive Manufacturing (LPBF-AM). The compositions, microstructures, together with mechanical, thermal, and corrosion properties of LPBF-AM Cu-10Sn specimens were investigated in the as-fabricated (AF) condition and after vacuum annealing (VA) at 600 degrees C and 800 degrees C. The AF specimens exhibit smaller grain sizes and higher compression strength than those of VA specimens, consistent with the Hall-Petch equation. Thermal conductivity of the AF specimens is around 10 % and over 20 % higher than that of the VA specimens annealed at 800 degrees C and 600 degrees C, respectively, which can be ascribed to the two-phase constituents of the AF specimens. The corrosion rate of the AF specimens is almost two times higher than that of the VA specimens due to the differences in passive layer, intergranular corrosion, and internal galvanic corrosion.
10.1016-j.addma.2020.101474	-1		When selecting a material for dies and molds, strength is needed at high temperatures to hold the shape of the component along with a high thermal conductivity to decrease the solidification time of the components. This need has led to the investigation of Cu to H13 tool steel bi-metallic structures. Utilizing a directed energy deposition experimental setup, two fabrication approaches were used: direct deposition of Cu on H13 and utilizing an intermediate layer of Deloro 22 (D22, > 95 wt% Ni content). Three structures were fabricated: Cu-H13 direct joints (DJ), Cu-D22-H13 multi-metallic structures (MMS), and D22-H13 DJ. In order to characterize the structures, the following was performed: microstructure characterization, elemental distribution, tensile testing, hardness, and thermal conductivity measurements. Directly joining the Cu onto the H13 resulted in cracking at the interface. By introducing D22 buffer layers, defect-free Cu was successfully deposited on H13. A sharp transition of elemental contents was experienced at the D22-H13 interface due to very limited layer diffusion. Across the D22-Cu interface, a gradual transition of Cu and Ni was detected, indicating a successive elemental diffusion. Tensile testing revealed that the Cu-D22-H13 MMS specimens fractured in the Cu zone with a morphology indicating a ductile fracture. The D22-H13 DJ failed in the D22 region although elongation mostly happened in the H13 section. The interfaces of both Cu-D22-H13 MMS and D22-H13 DJ survived tensile testing, indicating a strong bonding strength . Microhardness measurements observed an increased hardness at the surface of H13 due to laser hardening. The material hardness dropped rapidly across the Cu-H13 DJ but gradually in the Cu-D22-H13 MMS as the Ni in D22 diffused in multiple layers of the Cu. Thermal conductivity test shows the overall thermal conductivity of the Cu-D22-H13 MMS increased by approximately 100 % when compared with pure H13. The volume fraction of Cu can significantly affect the overall thermal conductivity of the Cu-D22-H13 MMS.
10.1016-j.addma.2020.101599	-1		Due to the aging hardening nature of Cu-15Ni-8Sn alloy, it is necessary to investigate the effect of aging on the properties of SLM-manufactured Cu-15Ni-8Sn alloy. In the present work, first, microstructural evolution of the alloys that underwent the direct aging treatment, solution treatment, and solution treatment plus aging are investigated in detail using scanning electron microscopy (SEM) and transmission electron microscopy (TEM); and second, mechanical properties and electrical conductivity of these samples were measured. After solution treatment, it's found that fine Sn-enriched precipitates resolved in matrix, an abundance of dislocation diminished, the grain size increased and a number of annealing twins formed. Spinodal decomposition could happen during the cooling of solution-treatment. According to the comparison of the microstructure and performance of the printed sample and the solution treated sample after aging, it's concluded that the strength and conductivity of the aged SLM-manufactured samples are higher than that of the aged solution-treatment samples for same aging duration, however, the plasticity and aging strengthening effect is inverted. The sharp decrement of plasticity is mainly ascribed to network discontinuous precipitations (DPs) in the grain boundary, but not the lamellar DPs. Annealing twin boundaries depressed the formation of DPs in the grain boundary, and improved the plasticity of aged solution-treatment samples. Lamellar DPs were also considered to be enhanced the strength of aged samples, besides modulated structures, D0(22) phase and L1(2) phase.
10.1016-j.addma.2020.101607	-1		Despite the high demand, the successful fabrication of fully dense, highly conductive, and strong copper components via laser powder bed fusion (LPBF) is not readily evident. This is mainly due to the low optical absorption of copper, which inhibits the complete melting of copper powders when using commercially available fiber-laser-based LPBF machines. Accordingly, this article proposes a novel approach of using optically absorptive metal-coated copper powders for the fabrication of fully dense, highly conductive, and strong copper components via LPBF. To validate this approach, the surface of the copper powder is modified by applying a very thin (62 +/- 14 nm) layer of metallic tin via an immersion plating technique. The application of only a 0.28 wt% of metallic tin coating significantly improved the room temperature powder optical absorption by similar to 170 % at the fiber laser wavelength . Consequently, crack-free and fully dense copper parts combining high thermal conductivity of 334 +/- 4 (W/(m.K)) and electrical conductivity of 80 +/- 1 % international annealed copper standard (% IACS) with a good tensile strength of 256 +/- 14 MPa, yield strength of 203 +/- 4 MPa, and ductility of 21 +/- 2 % have been fabricated using a fiber laser with an output laser power of 500 W. Furthermore, the article also describes the negative influence of the presence of a high amount of (0.091 wt%) sulfur, which originates from the organic additives during sub-optimal coating conditions, on the LPBF processing behavior of CuSn alloys. As such, high sulfur-containing tin-coated copper powders do not allow the fabrication of fully dense parts due to the occurrence of solidification cracks and the formation of pores. Subsequently, the optimum tin coating methodology, which limits the amount of sulfur below 0.0025 wt%, is described. The use of sulfur-free powder is recommended for the successful LPBF processing of fully dense parts made of copper and copper alloys.
10.1016-j.addma.2020.101825	-1		Laser metal deposition (LMD) additive manufacturing was utilized to fabricate a Cu-9Al-5Fe-5Ni alloy with a hierarchical microstructure and superior mechanical strength . An optimized processing window of LMD was established for printing the alloy with a relative density greater than 99% using laser power of 1000-1500 W, scanning speed of 0.5-1.5 m/min and hatch space of 1.5-2 mm. The LMD-printed alloy exhibited a microstructure consisting of a martensite beta* phase, a Widmanstatten a phase, Fe3Al and NiAl nanoprecipitates, and nanotwins. The hierarchical microstructure comprising microscale cellular structures, sub-microscale grains, and nanoscale precipitates and twins was achieved. The cellular structures were formed by the martensite beta* and a phases. The nanotwins were formed at the interface of the plate-like * phase, which was induced by the low stacking fault energy of the alloy and high cooling rate of LMD. The Fe3Al precipitates were formed within the beta* and a phases, while the NiAl precipitates were distributed in the beta* phase. The yield strength, ultimate strength, and elongation of the LMD-printed alloy were 593-713 MPa, 769-949 MPa, and 10-12%, respectively. The yield strength of the LMD-printed alloy was 160% and 76% higher than that of the counterparts fabricated by casting and wire arc additive manufacturing, respectively, which was attributed to the synergistic effects of the underlying mechanisms including the Hall-Petch type strengthening, dislocation strengthening, precipitation strengthening, and solid solution strengthening. These findings validated the applicability of LMD for printing the Cu-9Al-5Fe-5Ni alloy and facilitated the potential applications in marine and offshore industries.
10.1016-j.addma.2021.101888	-1		Laser powder bed fusion (L-PBF) of copper and copper alloys remain a challenge because of its low optical absorption and high thermal conductivity. L-PBF experiments were performed to print 2D (patches) and 3D (cubes) objects with pure copper under a low laser power (270 W max.). Patches reveal different surface morphologies allowing to select the best printing conditions for cubes. The highest reached cube relative density is 87.9%. To increase this value, a 1064 nm-absorptive physical vapor deposition (PVD) CrZr coating was performed on the copper powder to enhance its optical absorption. X-ray Photoelectron Spectrometry (XPS) and Auger measurements reveal the coating is oxidized, but increases the resulting CuCrZr powder optical absorption from 39% (value for pure Cu) to 81.8%. The CuCrZr powder was then used in the L-PBF process, and patches and cubes were successfully printed. The highest CuCrZr cube relative density reached 94.3%, highlighting the positive influence of a powder coating to create hard-to-melt metals or hard-to-atomized alloys under low laser power.
10.1016-j.addma.2022.102726	10	composites; nanoparticles; strength; matrix; high; strengthening; particles; conductivity; composite; electrical; mpa; sintering; ods; grains; mechanical	Cu-15Ni-8Sn alloy with layer-by-layer periodic heterogeneous microstructures composed of ultrafine equiaxed (similar to 2.6 mu m) and coarse columnar (similar to 12.8 mu m) grains was successfully fabricated by laser powder bed fusion (LPBF) additive manufacturing. The microstructures were composed of Sn-depleted alpha-Cu (Ni, Sn) matrix and Snenriched gamma-(CuxNi1-x)3Sn nano-precipitates. The gamma nano-precipitates were found to be mainly uniformly distributed at the melt pool boundaries due to Sn reverse segregation, as though the densely distributed seeds on the surface of a strawberry. The interesting periodic bi-modal microstructure exhibited a simultaneous positive effect on the enhancement of strength and ductility. The yield strength, ultimate tensile strength and elongation at break were (474.04 +/- 2.88) MPa, (584.36 +/- 4.74) MPa and (14.29 +/- 1.78)%, respectively. Remarkable improvements of 12% and 286% in the yield strength and elongation at break were achieved compared with those cast counterparts reported in the published literature. The high dislocations density (similar to 6.78 x10(14) m-2) were the dominant source of high strength and contributed-49% to the yield strength according to the theoretical calculation. Massive dislocation cells were generated around the gamma nano-precipitates during tensile deformation, improving the dislocation storage capacity and the work hardening ability. These findings validated the LPBF printability and the property enhancement of Cu-15Ni-8Sn and provided a promising strategy for the design of high strength and ductility copper alloys through layered precipitation microstructures.
10.1016-j.addma.2022.102847	5	materials; thermal; heat; properties; material; welding; sintering; fusion; strength; laser; heat sink; thermal conductivity; mechanical; sink; manufacturing	CuAl8 alloy finds applications in industrial components, where a good anti-corrosion and anti-wearing properties are required. The alloy has a medium strength and a good toughness with an elongation to fracture at room temperature of about 40%. Additionally, it has a good electrical conductivity, though lower than that of pure Al or pure Cu. Despite these characteristics, additive manufacturing of the CuAl8 alloy was not yet reported. In this work, the direct energy deposition-arc (DED-arc) with and without in-situ hot forging was used to determine the microstructure evolution and mechanical properties. No internal defects were seen on the parts produced. Hot forging combined with DED-arc was seen to reduce and homogenize the grain size, improve mechanical strength and isotropy of mechanical properties. Moreover, the use of this novel DED-arc variant was seen to reduce the magnitude of residual stresses throughout the fabricated part. We highlight that this alloy can be processed by DED-arc, and the hot forging operation concomitant with the material deposition has beneficial effects on the microstructure refinement and homogenization.
10.1016-j.addma.2022.103354	-1		The main objective of this work was to investigate the microstructure and mechanical properties of Cu-Cr-Nb (GRCop-42) and Fe-Ni-Cr (HR-1) alloy deposits produced using a high-pressure cold spray process. GRCop-42 powder blended with varying content of HR-1 powder (0, 15, 25, 50, 75, 85, and 100 wt%) was cold spray deposited, and the microstructure and mechanical properties of the deposits were evaluated. The deposits were characterized using optical microscopy, X-ray diffraction, and scanning electron microscopy. The use of He process gas resulted in relatively lower porosity and better mechanical properties compared to the deposits produced with N2 process gas. In the as-deposited condition, all the cold spray deposits exhibited brittle behavior with no appreciable ductility. Post-deposition heat treatment significantly improved ductility and tensile strength for both GRCop-42 and HR-1 deposits. However, post-deposition heat treatment resulted in coarsening of Cr2Nb precipitates in GRCop-42, the formation of eta phase in HR-1, and the formation of sigma phase at the interface in GRCop-42 and HR-1 composite deposits.
10.1016-j.addma.2023.103617	-1		To enhance the compatibility of Cu with laser powder bed fusion, pre-alloying or powder surface modification of introducing high laser-absorbing alloying elements is currently adopted. However, this only addresses the densification issue but sacrifices the more important electrical/thermal performance because of their supersaturated solid solution in Cu. A secondary heat treatment is required though it is highly risky in damaging the dimension of geometrically complex component. Here, a novel strategy of employing the high laser-absorbing inert Cr2O3 instead of solid-solution alloying elements for powder surface coating was effective in achieving the desired synergy of densification (99.5 %) and electrical/thermal conductivity (91.8 % IACS and 371 W m-1 K-1), by which no additional heat treatment is needed. A heat sink was built to verify these positive effects. The electrical/thermal conductivity obtained is equal to those for the printed Cu alloys after long-term heat treatment. This strategy is universally applicable to other inert candidates.
10.1016-j.addma.2024.104100	-1		Employing a single strategy that overcomes the strength-ductility-conductivity trade-off in copper alloys has proven to be challenging. In this study, we introduced a novel heterogeneous nanoprecipitate-dislocation (HND) architecture in CuCrNb alloy consisting of a multi-modal core-shell grain structure and an interconnected dislocation network pinned by abundant nanoprecipitates. Our CuCrNb-HND alloy exhibited superior strength-ductility synergy at both room and elevated temperatures. In particular, aging treatment-induced highdensity coherent Cr secondary nanoprecipitates into the HND skeleton endowed the CuCrNb-HND450 alloy with a high tensile strength of over 1 GPa and a conductivity of similar to 50%, surpassing those of most of the reported additively manufactured copper alloys. An in situ transmission electron microscopy heating experiment revealed the superior thermal stability of the HND architecture. Hierarchical strengthening contributed to the enhancement of mechanical properties. At the micrometer scale, the harmonic grain structure with a strong fine-grained shell and a ductile coarse-grained core effectively improved mechanical properties by suppressing localized plastic deformation. At the nanometer scale, the synergistic effect of the nanoprecipitate-dislocation network further improved the alloy strength by slowing down dislocation movement. Overall, our proposed HND architecture provides an efficient pathway for developing high-strength and high-conductivity copper alloys.
10.1016-j.addma.2024.104166	-1		Multi -material laser powder bed fusion has long been a challenge in additive manufacturing, especially in terms of controlling spatial variations and joining multiple materials. The challenge is even greater when multimaterial components have different physical properties (e.g., different thermal expansions, thermal conductivities and laser reflectivities). The aforementioned scenario is applicable to copper-nickel (Cu-Ni) alloy. The simultaneous printing and controllable mixing of pure Cu and pure Ni within a single print have not been accomplished due to the substantial disparity in the physical properties of pure Cu and pure Ni. In this work, a full composition with different mixing proportions (100 % Cu to 100 % Ni) was fabricated in a single printing process through in -situ alloying based on our process of micro laser powder bed fusion. A transition from a columnar grain to a quasi-equiaxed grain morphology with texture variation from <110 > to <111 > was found in the full-composition-gradient of the Cu-Ni alloy. Microstructural variations, such as fine grain strengthening and grain boundary strengthening, greatly affected the mechanical properties of the alloys: the ultimate tensile strength ranged from 303 to 488 MPa and the yield strength ranged from 231 to 445 MPa. Moreover, the electrical conductivity of the alloys with a compositional gradient ranged from 3.6 % IACS to 96 % IACS due to the electron scattering induced by lattice distortion. In summary, a full -composition Cu-Ni gradient alloy was fabricated through in -situ alloying adopting micro laser powder bed fusion for the first time, enabling the investigation of the evolution of the microstructure and properties of the alloy as the alloy composition varies.
10.1016-j.addma.2024.104244	-1		Printing Cu alloys with simultaneously high strength and high electrical conductivity by laser powder bed fusion remains a challenge. In conventionally manufactured Cu alloys, nanoprecipitates form through alloying elements to impart significant strengthening effects while having a lesser impact on electrical conductivity. However, the ultrahigh cooling rate of laser powder bed fusion promotes the supersaturated solid solution of alloying elements, resulting in severe lattice distortion in the Cu matrix and a significant compromise in electrical conductivity. Therefore, it is vital to select Cu alloying elements that substantially prevent the formation of a supersaturated solid solution in laser powder bed fusion to achieve outstanding strength while maintaining sufficient electrical conductivity. In this study, we fabricated a Cu-O alloy with high strength (491.6 MPa) and high electrical conductivity (68.0 % IACS) using laser powder bed fusion. The alloy features a cellular microstructure in which Cu2O nanoprecipitates are configured orderly as the cellular boundary. This cellular microstructure can promote strength by impeding dislocation motion and maintain a high electrical conductivity by preserving a longer free path for conductive electrons. This study explores the potential of combining the alloy composition and extreme process conditions of laser powder bed fusion to provoke unique microstructures and overcome the dilemma between strength and electrical conductivity in Cu alloys.
10.1016-j.addma.2024.104521	-1		In this study, Cu-11.1Al-8.15Mn-0.37Si shape memory alloy was manufactured via laser powder bed fusion (LPBF) and compared with furnace-cooling cast samples. The LPBF-manufactured samples exhibited a dual-phase structure of L21 austenite and 2H martensite, along with uniformly distributed nanoscale Mn5Si3 precipitations observed via TEM. The 2H martensite presented a layer-like morphology and was confirmed to be induced by residual stress during the LPBF process. Such a dual-phase structure could be stabilized by Mn5Si3 precipitations, and yielded the concurrent presence of prominent superelastic (SE) and shape memory effect (SME) properties. Under 6 % pre-strain, LPBF-manufactured samples showed an 80 % SE rate and 83 % SME rate. The recovery SE and SME strain could be up to 4.2 % and 2.1 %. Compared to the cast sample, fracture compressive and tensile strain increased by 68.4 % and 33.3 %. This enhancement was due to regularly arranged columnar crystals and strong [001]//Z texture confirmed by EBSD. These findings suggest that LPBF has the potential to produce Cu-AlMn-Si alloys with prominent shape memory properties and provide references for an austenite-martensite dualphase structure.
10.1016-j.addma.2024.104630	-1		The focus of 4D printing research has shifted from fabrication to precisely control the properties and functionalities of smart materials. Enhancing shape memory recovery and cyclic stability of Cu-based shape memory alloys (SMAs) become crucial. In this study, (84.95-x)Cu-11.85Al-3.2Ni-xMn (x = 0, 1, 2, 3, 4, 5 wt%) SMAs were fabricated using laser powder bed fusion (LPBF) via powder mixing strategy and multiple optimization designs. The addition of manganese (Mn) significantly decreased the martensite transformation temperature, thereby influencing the printability, microstructure, and performance of the Cu-Al-Ni-Mn SMAs. An as-built sample containing 3 wt% Mn exhibited superior mechanical properties (ultimate tensile strength of 699 +/- 5 MPa and elongation of 8.95 +/- 0.02 %), excellent shape memory recovery (shape memory strain of 2.69 % and shape recovery ratio of 100 % under 4 % pre-strain), and stable cyclic properties under 2 % pre-strain. This study also discusses the deterioration of printability with increasing Mn content, microstructural evolution with varying Mn contents, and the mechanism of performance change due to Mn addition and thermomechanical cycling in detail. This research highlights the potential of 4D printed Cu-based SMAs with enhanced shape memory and cyclic properties, thus, providing a reference for performance improvement and advanced alloy design for further studies.
10.1016-j.addma.2025.104723	14	strength; properties; conductivity; electrical; mechanical; cu-; grain; mpa; electrical conductivity; aging; precipitation; phase; mechanical properties; tensile; phases	Cu-Sn alloys produced via laser powder bed fusion (L-PBF) additive manufacturing (AM) have gained significant attention because they combine the advantages of AM relevant to intricate component design with outstanding combinations of strength, ductility, and resistance to wear and corrosion. However, a detailed understanding of the microstructure that contributes to the enhancement of the mechanical properties of L-PBF Cu-10Sn alloys remains unclear. In particular, there is a lack of understanding of the formation mechanisms of the Sn-rich delta phase commonly observed in Cu-10Sn. This study reveals two distinct variants of the delta phase possessing unique morphological characteristics. These characteristics are attributed to the local solidification conditions inherent to the melt pool boundaries versus those at the interiors of melt pools. A phase transformation pathway that elucidates the origin of the morphological variants of the delta phase from the Sn-rich metastable phases during the cyclic heating of the AM process is proposed. We report superior mechanical properties in L-PBF Cu-10Sn compared to those of conventionally manufactured counterparts due to the synergistic contributions from grain boundaries, dislocations, and the delta phase. Notably, the delta phase alone contributes approximately 22 % to the overall strength observed in the L-PBF Cu-10Sn alloy. The discovery of two types of distinct Sn-rich delta phase offers key insights into precise microstructural control in AM Cu-Sn alloys to enhance mechanical properties, providing practical strategies for improving material performance for diverse applications in automotive, aerospace, and machinery industries.
10.1016-j.addma.2025.104787	-1		Directed energy deposition (DED) has demonstrated significant potential for component repair, owing to its flexibility in deposition path and powder feedstock selection. However, research on manufacturing Cu-Al alloys via DED remains limited. This study employed a pre-mixed blend of CuNi2SiCr and Al-Mg-0.7Si powders to synthesize Cu-Al alloys in situ for the DED-based repair of nickel-aluminum bronze (NAB). By varying the mass fraction of the Al-Mg-0.7Si powder (6, 8, 10, and 12 wt%), the effects of aluminum content on the microstructure, hardness, and tensile behavior of the repaired samples were investigated by micro- and nanoscale characterization. The results indicated that all repaired samples were free of obvious defects, such as pores or thermal cracks, and exhibited excellent metallurgical bonding between the repaired area and substrate. The microstructures of samples containing 6 and 8 wt% Al-Mg-0.7Si powder were predominantly alpha phase while those with 10 and 12 wt% Al exhibited beta 1 martensitic twin structures. The samples repaired with 6 wt% Al-Mg-0.7Si powder demonstrated the best tensile properties, with a tensile strength of 624 MPa and elongation of 14.4 %. The tensile properties of the 10 and 12 wt% Al samples were lower owing to the precipitation of the Widmanstatten alpha phase at the beta 1 martensitic grain boundaries. Fracture locations varied across samples, but cracks did not propagate along the repaired interface, suggesting excellent interfacial bonding strength . Additionally, unusual gamma 2 phase precipitates were observed in all the samples. This research provides valuable insights into the feasibility of in-situ Cu-Al alloy fabrication via DED for the repair of NAB.
10.1016-j.addma.2025.104869	-1		Due to their high thermal and electrical conductivity and high resistance to arc erosion, Cu-Cr alloys (Cr >10 wt%) are used as electrical contacts in medium voltage vacuum circuit breakers. Such electrical contacts are industrially processed using solid-state sintering (SSS) from pure Cu and Cr powders or vacuum arc remelting (VAR). In this work, we confirm the possibility of fabricating dense Cu-25Cr samples with a refined and relatively homogeneous microstructure by electron beam powder bed fusion (EB-PBF) using elemental powder blending. The as-printed microstructure is characterized using SEM imaging and EBSD analysis while the mechanical, electrical, and thermal are probed to establish the microstructure-property relationships of the EB-PBF Cu-25Cr composite. The properties of the EB-PBF composite are systematically compared to their VAR counterparts. The as-printed microstructure results from the presence of a metastable miscibility gap that refines the microstructure (micron-sized Cr particles) by an order of magnitude compared to the VAR. The fine EB-PBF microstructure shows superior mechanical properties (hardness, yield strength and ultimate tensile strength), enhanced electrical conductivity, and equivalent thermal conductivity with respect to its VAR counterpart. The microstructure-property relationships are discussed in light of the mechanisms affecting the mechanical, electrical, and thermal properties of metal matrix composites. This work demonstrates the interest in producing Cu-Cr electrical contacts by additive manufacturing.
10.1016-j.addma.2025.104874	5	materials; thermal; heat; properties; material; welding; sintering; fusion; strength; laser; heat sink; thermal conductivity; mechanical; sink; manufacturing	Based on its excellent electrical conductivity in combination with a high arc erosion resistance and withstand voltage, the alloy Cu-25Cr is widely applied as a contact material for high-power vacuum interrupters. The utilization of the electron beam powder bed fusion (PBF-EB) method for the processing of this material offers the major advantage of producing extremely fine Cr precipitates due to the rapid solidification of the melt pool, which can further improve the application-specific properties significantly. In this work, the in-situ alloying of Cu-25Cr from an elemental powder blend via PBF-EB was investigated numerically and experimentally, which resulted in the development of a first process window for the production of dense and well-mixed samples. In doing so, the number of necessary experimental tests could be greatly reduced by using numerical predictions for the definition of the design of experiments. In addition, simulations were used to gain an understanding of the formation mechanism of characteristic defects. These calculations were carried out using an in-house developed software, which was successfully validated against the experimental results. As part of the experimental tests, it was demonstrated that the powder mixture does not segregate during its application on the start plate, which forms the basis for the reliable production of components with a consistent composition. At a build temperature of approximately 600 degrees C, it was then possible to produce cuboid samples with a porosity of smaller than 0.1% and a fraction of unmolten Cr particles of smaller than 0.2%.
10.1016-j.addma.2025.104950	-1		This study investigates the cracking mechanism in additive manufacturing of Ni-Cu multi-material combinations using operando X-ray diffraction and imaging experiments during laser powder-bed fusion (L-PBF) of CuCrZr and IN625. It is shown that liquid immiscibility between the two alloy systems stems from the interaction between Cu and the alloying elements in IN625, causing both Cu-rich and Ni-rich liquids to form with different freezing ranges. Consequently, solidification cracking takes place due to the large solidification range where the Ni-rich solid and Cu-rich liquid co-exist. Guided by thermodynamic calculations, it was identified that the highest crack susceptibility occurs between 20 and 40 wt% CuCrZr-IN625, which was further validated by printing mixtures of the two alloys in different ratios. Operando X-ray imaging and scanning electron microscopy characterization revealed that the cracking occurred during the terminal stage of solidification. It was observed that the columnar grains of the Ni-rich primary solid separate into cracks, where Cu-rich liquid regions persist over a wide temperature range as the solidification of these regions begin significantly later. It was concluded that the mechanism of cracking explained in this study could be extended to other Cu-Ni alloy combinations containing elements that induce immiscibility when mixed with Cu during fusion-based processing methods.
10.1016-j.addma.2025.104988	14	strength; properties; conductivity; electrical; mechanical; cu-; grain; mpa; electrical conductivity; aging; precipitation; phase; mechanical properties; tensile; phases	Laser Powder Bed Fusion (PBF-LB) of copper and low-alloyed copper alloys remains challenging due to their low infrared absorptivity and high thermal conductivity. This study introduces a multi-faceted strategy integrating computational thermodynamics-guided alloy design, Mo nanoparticle surface decoration, and thermal process optimization to enable robust and energy-efficient PBF-LB processing of reflective Cu-based alloys. Surface decoration with 0.44 wt% Mo nanoparticles enhances laser energy absorption, enabling a 40-45 % reduction in the required laser volumetric energy density from 167 to 188-100-118 J/mm3 to achieve > 99.1 % part density. Additionally, Mo addition improves the alloy's resistance to precipitate coarsening while maintaining low solid solubility in Cu, thereby preserving electrical conductivity. In CuCrZr alloys, baseplate preheating to 300 degrees C promotes densification and in-situ precipitation of Cr and CuxZry phases during PBF-LB, enhancing both strength and conductivity. In contrast, Mo addition suppresses in-situ precipitation due to its sluggish diffusion in Cu and preferential partitioning into Cr and CuxZry phases. After direct age-hardening (450 degrees C, 9 h), the CuCrZrMo alloy exhibits a fine dispersion of Mo-doped nanoprecipitates, achieving a yield strength of 598 f 7 MPa (vs. 576 f 7 MPa for CuCrZr) while retaining high electrical conductivity (67-68 % IACS). This work highlights a synergistic alloy and process design strategy to address key PBF-LB challenges in Cu alloys, enabling their application in high-performance components requiring combined high mechanical strength and electrical conductivity.
10.1016-j.aej.2020.12.027	2	corrosion; surface; film; electrochemical; films; spectroscopy; layer; current; solution; potential; resistance; composition; x-ray; ions; showed	Effects of electrolyte solution (i.e., KOH, NaOH, NaCl, and HCl) with various concentrations (from 0 to 0.71 M) on corrosion and mechanical properties of the copper alloys were investigated. Experimental results showed that the increases in the concentration of electrolytes allowed faster corrosion process. However, too high concentration of electrolytes has no further impacts on the corrosion profile due to the existence of the passivity phenomena on the surface of the material, preventing the material to get more corroded. Acidic (HCl) and salt (NaCl) electrolytes gave more impacts on the corrosion compared to the alkaline solution (i.e., NaOH and KOH) since the acidic and salt ions are able to destroy the formed passivation layer. The correlation of the corrosion rate and the mechanical properties was also presented, in which the increases in the corrosion rate were in line with the decreases in the mechanical properties (i.e., tensile and yield strength). During the corrosion, the atomic structure in the material received attacks from the electrolyte ions, making the structure inside the copper alloys to be less strong and easily fatigued. Understanding the corrosion process and mechanical properties is important for further applications of copper-related alloys in extreme and severe conditions. (C) 2020 THE AUTHORS. Published by Elsevier BV on behalf of Faculty of Engineering, Alexandria University.
10.1016-j.apmt.2025.102807	-1		The exploration of high-strength Cu alloys at low costs is of critical importance to the industry. Here, we report a high-strength CuZnSnAlP alloy based on the traditional CnZn alloys by introducing nanometer AlP secondary phase. AlP present higher shear modulus and hardness than the matrix, which impedes dislocation motion and then increases the strength . The ultimate tensile strength of 908 MPa can be obtained on cold-rolled sample. In addition, the precipitation of AlP reduces the lattice distortion of the CuZn matrix, giving rise to an improved plasticity and conductivity. The sample 0.2 mm in thickness could maintain a high tensile strength of 704 MPa and, exhibiting a good elongation of 16.2 % and high conductivity of 25.4 % IACS after multiple annealing process.
10.1016-j.apmt.2025.102839	14	strength; properties; conductivity; electrical; mechanical; cu-; grain; mpa; electrical conductivity; aging; precipitation; phase; mechanical properties; tensile; phases	A novel CuFeCo-based immiscible medium-entropy alloy (IMMEAs), specifically synthesized as (Cu60(Fe-Co)40)95Ni5, (Cu60(FeCo)40)90Ni10, (Cu60(FeCo)40)90Mn10 and (Cu60(FeCo)40)95Al5, was fabricated through vacuum induction melting, taking advantage of the immiscible nature inherent to CuFeCo alloys. Phase separation was observed between the Cu-rich phase and the FeCo-rich phase, with Ni segregating into the Cu phase, Mn enriching the FeCo phase, and Al being uniformly distributed across both phases. A stable dual-phase structure comprising both face-centered cubic (FCC) and body-centered cubic (BCC) phases was formed in (Cu60(Fe-Co)40)95Ni5, (Cu60(FeCo)40)90Mn10 and (Cu60(FeCo)40)95Al5. In contrast, a dual-phase structure consisting of a Cu-rich FCC phase and a FeCo-rich FCC phase was observed in (Cu60(FeCo)40)90Ni10 initially. Notably, cold rolling and aging treatments induced partial transformation of the FeCo-rich FCC phase into the FeCo-rich BCC phase in (Cu60(FeCo)40)90Ni10. The synergistic effects of solution strengthening, heterogeneous deformation-induced (HDI) strengthening, and nanoscale annealing twins significantly contributed to the enhancement of mechanical properties. Among the alloys, (Cu60(FeCo)40)90Mn10 exhibits superior tensile strength, hardness, and saturation magnetization. In contrast, (Cu60(FeCo)40)90Ni10 demonstrates enhanced elongation and lower coercivity, while (Cu60(FeCo)40)95Ni5 shows improved conductivity. This work expands the design paradigm for IMMEAs with tailorable multifunctional properties.
10.1016-j.apradiso.2022.110483	-1		In this study, seven alloys with a nominal composition of (CuO2)0.5 M0.5 (M = Fe, Co, Ni, Cu, Zn, Y, and Nb wt%) were produced via the powder mixed method. Alloys and pure metals were excited with 59.54 keV photon energy emitted from Am-241 radioactive source at 25 degrees, 35 degrees, 45 degrees, 55 degrees, 65 degrees, 75 ' and 85 degrees scattering angles. The spectra of the coherent/Compton peaks were obtained by Si(Li) detector. First of all, chemical shift, (AE) peak energies, (E) asymmetry index (As) and full width half maximum (FWHM) values were found in the Compton/ Coherent scattering spectra obtained depending on the scattering angle and the chemical environment of the transition metals. Then the ratios of the Coherent/Compton scattering differential cross-section (dacoherent/ daCompton) were obtained experimentally. The experimental dacoherent/daCompton ratios of the selected 3d-4d transition metals were found to be compatible with the data in the literature. Asymmetry and chemical shifts were observed in almost all samples, especially in Compton peaks, with increasing scattering angles. The chemical shifts of Compton and Coherent peaks of the alloys were found in the range of 1-932 eV. The exper-imental dakoherent/daCompton ratios for the alloys obtained by adding Fe, Co, Ni, Cu, Zn, Y, and Nb to Cu2O were found as 0.697, 0.689 0.678, 0.698, 0.736, 0.755, 0.798, 0.835 at 45 degrees scattering angle, respectively. It has been determined that the experimental dacoherent/daCompton ratio for each alloy increases with increasing atomic number, while it decreases with increasing scattering angle.
10.1016-j.apradiso.2023.110957	-1		K & beta;/K & alpha; X-ray intensity ratio values of Cu and Ag in CuxAg1-x (x = 53.5, 67.6, 76.9, 85.4, 89.6) thin alloy films produced from two different sources by the physical vapour deposition method have been determined by the Energy Dispersive X-ray Fluorescence Spectroscopy (EDXRF) method. The changes in the crystal structures of CuxAg1-x thin alloy films caused by the changes in the Cu and Ag concentrations, which affect the valence electronic structure have been investigated by the X-ray Diffraction (XRD) techniques. The obtained values were compared with the theoretical and fitted values for pure Cu and Ag elements.
10.1016-j.apsusc.2005.07.153	-1		Plasma plume emission spectroscopy signal enhancements between 12- and 280-fold were obtained in air at atmospheric pressure by reheating the fs-laser ablation plume (energy 0.75 and 3.0 mJ) with a 45 mJ ns-pulse in orthogonal geometry. The emission enhancements induced by the double pulse configuration (DP) at various inter-pulse delay times and distances of the second laser beam from the target surface were investigated for copper-based-alloy standards. Temporal surveys of the plasma plume temperatures induced by both fs-single pulse (fs-SP) and DP placed at a fixed distance of 0.5 mm from the target surface were carried out. Several copper-based-alloy standards were employed for drawing Zn calibration curves by using either fs-SP or DP configurations and considering Cu as internal standard. The experimental data show that, for high Zn contents, the fs-SP set-up is affected by a self-absorption phenomenon so that a deviation from the assumed calibration single linear response is observed and two linear regressions are considered. Conversely, it has been observed that the DP configuration is not affected by any self-absorption effect and provides an improvement of the Zn limit of detection (LOD) but worse calibration linear regressions than the fs-SP. Thus, the DP scheme can increase the analytical sensitivity of fs-SP and, furthermore, its process can be supposed to be independent from the matrix composition even for largely different Zn contents of the Cu-based-alloy standards used.
10.1016-j.apsusc.2006.02.117	-1		TOFSIMS elemental mapping was applied to characterize SiC reinforced copper. SiC grain in Cu, compressed by hot isostatic pressing, is an innovative substrate material for improved heat dissipation of high-power semiconductor devices so that traditional substrates like Cu, Al, Al2O3 and metal alloys could be complemented. The TOFSIMS imaging capabilities combined with its excellent detection limits were used to monitor the matrix components as well as the distribution of an alloying additive (Ti) which is necessary to improve the mechanical strength . It turned out that SiC-Ti interface reactions lead to a dissipation of Si into the Cu matrix which deteriorates heat conduction. The TOFSIMS analyses helped to gain a better understanding of the complex Cu/SiC composite system which in turn gives room for further process improvements.
10.1016-j.apsusc.2007.02.053	2	corrosion; surface; film; electrochemical; films; spectroscopy; layer; current; solution; potential; resistance; composition; x-ray; ions; showed	The corrosion products of a TM 23 bronze-leaded alloy (Cu 72%, Pb 15%, Zn 8% and Sn 5%) were obtained in a salt spray cabinet after exposition during 120 h and 1000 h . The products obtained were studied using scanning electron microscopy, energy dispersive spectroscopy, and X-ray diffraction. The major products of bronze-leaded corrosion were oxides and basic salts of Cu, CuCl2 center dot 3Cu(OH)(2), and Pb, Pb(OH)Cl. The results can be attributed to a kinetic control of the corrosion reactions.
10.1016-j.apsusc.2007.05.017	2	corrosion; surface; film; electrochemical; films; spectroscopy; layer; current; solution; potential; resistance; composition; x-ray; ions; showed	Benzotriazole (BTAH) is an excellent inhibitor for the corrosion of copper and many of its alloys in unpolluted media. Protection is attributed to the formation of a film of Cu(I)BTA. Injection of sulfide ions into a benzotriazole inhibited salt water damages the protective Cu(I)BTA film very rapidly, increases the corrosion rate and leads to the formation of copper sulfide. This effect is quite marked at a sulfide concentration as low as 10(-5) M (about 0.3 ppm sulfur) in the presence of 10(-2) M BTAH, which is 1000-fold greater than that of the sulfide ion. The intensity of sulfide attack increases with its concentration. Prolonged pre-passivation of copper in the BTAH protected medium even at high concentration does not markedly improve the resistance of the protective film to sulfide attack. This finding is contrary to a well-documented phenomenon in unpolluted media where the inhibiting efficiency of BTAH increases with the time of immersion and the concentration of the inhibitor. X-ray photoelectron spectroscopy (XPS) reveals the presence of both sulfide and BTAH on the corroded surface indicating that sulfide attack is localized.
10.1016-j.apsusc.2007.06.049	2	corrosion; surface; film; electrochemical; films; spectroscopy; layer; current; solution; potential; resistance; composition; x-ray; ions; showed	In order to study nickel ion release associated with nickel allergy, Cu-18Ni-20Zn nickel-silver alloy was immersed in artificial sweat and Ringer physiological solution for 30 days. Dissolution of metal ions was measured as a function of time, and the characteristics of the solid surface layer formed after 30 days were studied by SEM/EDS and XPS. The dissolution of nickel prevails over dissolution of copper and zinc. Nickel release in artificial sweat is approximately 10 times higher than in Ringer physiological solution and in both solutions the nickel release exceeds 0.5 mu g cm(-2) week(-1), the threshold above which the allergy is triggered. Evidence of selective nickel dissolution is reported. The composition of the surface layer formed in artificial sweat and in Ringer physiological solution differs in the content of nickel and chlorine. In artificial sweat, the major constituents of the surface layer are dominantly oxides, Cu2O and ZnO, with traces of chlorine. In Ringer physiological solution, the composition of the surface layer changes to a mixture of oxides, chlorides and/or oxychlorides. Two components peaks were detected in the Cl 2P(3/2) peak; however, it was not possible to distinguish the exact nature of the chloride compound formed. The mechanism of nickel release is discussed as a function of the composition of the solution.
10.1016-j.apsusc.2007.07.040	4	transformation; martensite; martensitic; phase; shape; beta; memory; shape memory; temperature; temperatures; martensitic transformation; gamma; transformation temperatures; effect; thermal	When Cu-Zn alloys are annealed under dynamical vacuum the Zn component evaporates. The process is called dezincification. This paper presents the results of the dezincification of highly mechanically deformed surfaces of samples initially in the beta (bcc) phase by a combination of in situ optical microscopy observations together with TEM measurements. It is shown that grinding lines remaining from the sample preparation process act as nucleation centers for the alpha (fcc) phase. Under this surface preparation conditions the new fee phase nucleates with a different geometry than the one reported in previous papers in which surfaces were finished by electropolishing. In the present case, we observe individual fcc precipitates with a well defined geometry. The typical size of precipitates is in the micron range, and depends on the dezincification parameters: final temperature, dezincification time and prior surface preparation. TEM observations show that the fcc precipitates contain a large density of defects, mainly dislocations and twin boundaries. (C) 2007 Published by Elsevier B.V.
10.1016-j.apsusc.2008.05.116	-1		Secondary ion mass spectrometry (SIMS) was used for characterizing the depth distribution of small amounts of alloying elements in three different copper-based dilute alloys, i.e., copper-chromium, copper-iron, and copper-nickel-silicon alloys. The samples were annealed at high temperatures under a low oxygen partial pressure. The SIMS depth profiles revealed that oxygen penetrated the copper-based alloys, and chromium and silicon were enriched on the surface side so as to form oxides during annealing. On the other hand, chromium and silicon were depleted beneath the enriched surface layer. However, the depth profile of iron was similar to that of copper. These phenomena were likely to be correlated with the reactivity of the alloying elements with oxygen. The formation kinetics of the depleted zones of chromium and silicon has been discussed on the basis of the selective oxidation of these alloying elements.
10.1016-j.apsusc.2010.09.117	-1		Nanoporous manganese was fabricated by a three-step process involving high power laser cladding of a homogeneous Cu40Mn60 alloy coatings onto a mild steel substrate, laser remelting for tuning the grain size and the composition homogeneity followed by selectively electrochemical de-alloying for removal of Cu element and formation of nanoporous Mn. The microstructure and homogeneity of the precursor Cu40Mn60 alloys have a significant influence on the evolution of nanopores during selectively electrochemical de-alloying. Laser remelting can significantly refine the microstructure. The second dendrite arm spacing decreases with increasing of laser remelting scanning speed. A SDAS of 1.17 mu m was obtained at the laser scanning speed of 133 mm/s. When the remelting scanning speed reaches 100 mm/s, a nanoporous structure with average pore size less than 100nm was achieved under optimized dealloying electrode current density about 2mA/cm(2). Nanoporous Mn with nanopore sizes ranging from 80 to 130nm was fabricated by this method. Surface-enhanced Raman scattering characteristics of the nanoporous materials have been investigated. It is found that smaller nanoporosity leads to significant improvements in surface-enhanced Raman scattering.
10.1016-j.apsusc.2011.02.060	-1		The isotherm wetting and spreading behaviors of the molten Cu-Cr alloys with 0.5, 1.0 and 2.0 at% Cr on porous graphite substrates were investigated at 1373K in a flowing Ar atmosphere using a modified sessile drop method. The wettability improves with increasing Cr content in the alloy as a result of phase transition from Cr3C2 to more wettable and metallic-like Cr7C3 developed at the interface. The spreading kinetics are controlled by the interfacial reaction in the early stage and the diffusion of Cr from the drop bulk to the triple junction in the later stage together with a transition in the intermediate stage.
10.1016-j.apsusc.2011.08.122	2	corrosion; surface; film; electrochemical; films; spectroscopy; layer; current; solution; potential; resistance; composition; x-ray; ions; showed	A single phase Cu-Zn-Bi film is fabricated on the steel wire by electrodeposition. Bi addition (similar to 1 wt%) greatly increases the corrosion resistance of brass (Cu-36 wt% Zn) film in a 0.05 M K2SO4 solution as shown by potentiodynamic polarization and electrochemical impendence spectroscopy (EIS) experiments. It is proposed that the main reason for the improvement in the corrosion resistance by the Bi addition is that it greatly increased the crack resistance, which thus prevents crack-induced galvanic corrosion occurring between the brass film and the steel substrate.
10.1016-j.apsusc.2012.04.070	-1		Both the cryomilled Cu powder and the gas-atomized Cu powder were sprayed onto aluminum substrate using the cold spray process. This study focused on the formation and tribological behavior of the nanocrystalline (NC) Cu coating in comparison to its coarse-grained (CG) Cu counterpart. The results showed that the as-sprayed deposit presented a dense microstructure. The mean grain size of the NC Cu coating was about 30 nm. Investigations on the worn surface of the NC coating revealed that the plastic deformation with grooves and some debris were prominent with no visible cracking. Nanocrystalline Cu coating showed a good wear resistance with a low friction coefficient. The enhancement of the wear properties of the NC Cu was attributed to the grain refinement and the superior hardness.
10.1016-j.apsusc.2012.12.050	2	corrosion; surface; film; electrochemical; films; spectroscopy; layer; current; solution; potential; resistance; composition; x-ray; ions; showed	The corrosion resistance of Cu-Zn alloys strongly depends on the quality of the protective passive film. This study focuses on the influence of Zn on the composition of oxide films on copper and brass (Cu77Zn21Al2) in borax 0.1 mol L-1 (pH 9.2) solution, where the solubility of copper oxides is minimal. The effect of the presence of chloride ions at low concentration (0.01 mol L-1) in the electrolyte was also evaluated. Both conditions were studied using a set of different electrochemical, optical and surface techniques such as cyclic voltammetry, differential reflectance, X-ray photoelectron spectroscopy and Raman spectroscopy. A duplex Cu2O/CuO layer forms on copper at potentials positive to the open circuit potential (OCP), while in the case of brass, zinc compounds are also incorporated to the surface film. It also became evident that a surface film can be formed on these materials even at potentials negative to the OCP. Zn(II) species are the main constituents of the films growing on brass, while copper oxides are incorporated to the surface film when approaching the OCP. The presence of chloride ions at low concentrations contributes to the dissolution of the oxo-hydroxides formed during the early stages of the aging process at open circuit potential. Also, copper chloro-compounds are formed, as shown by Raman spectroscopy for both copper and brass electrodes.
10.1016-j.apsusc.2013.10.066	-1		This research analyzed the influence of the electrodeposition ratio of Cu-Ni on the creation of microstructure in Cu-Ni composite electrodeposition, and identified the microstructure generation mechanism with respect to the Cu-Ni electrodeposition ratio. The concentration of CuSO4 in the electrodeposition solution was varied to 0.00, 0.02, 0.04 M to control the electrodeposition ratio of Cu, and the applied voltage was varied to voltages of -0.9, -1.2, -1.5 V, which were applied to control the electrodeposition ratio of Ni. In the composite electrodeposition, Cu ions precipitated intensively at the top of the structure with a short ion diffusion length, and the Ni ions precipitated regularly throughout the entire area charge transferred. Therefore, the structure showed vertically oriented growth when Cu electrodeposition was dominant, and the structure showed isotropic growth when Ni electrodeposition was dominant. On the other hand, Cu ions precipitation concentration at the tip of the grown structure intensified as the height of the structure increased. Therefore, when a structure grows above a certain height, the excess Cu ions precipitate at the top of the grown structure and a cluster structure composed of spherical Cu particles develops. The microstructure produced in the electrodeposition solution with the CuSO4 concentration of 0.04 M had such a high structure generation density and aspect ratio that it was modified to a superhydrophobic surface with a contact angle higher than 150 degrees, and it manifested an excellent self-cleaning ability.
10.1016-j.apsusc.2014.04.096	-1		Copper (Cu)-carbon nanotube (CNT) composite surface coatings with CNT contents of up to 15 vol.% were fabricated by mechanical alloying (MA) and cold gas dynamic spray (CGDS) process. The MA powder and CGDS coating samples were characterized by weight and size measurements, optical microscopy, scanning electron microscopy, energy-dispersive X-ray spectroscopy, and X-ray diffraction. The coatings were also examined by profilometry and porosimetry. The results showed that the particle sizes of MA composite powders and their deposition efficiencies (DEs) in CGDS decreased with the increase of CNT content. The DE also decreased with the increase of coating layers. The XRD results indicated that the composite powders and coatings had microstrains and undergone grain size reduction due to the deformation caused by MA and CGDS. The coating surface and internal microstructures had flattened lamellar features, which indicated severe deformation that resulted from impact during the deposition of particlesas well as from the impact of the rebounded particles. Some internal pores were present along the interfaces of the deposited particles. The surface roughness values of the coatings were observed to be related to the sizes of the powder particles. The roughness tended to decrease with the reduction of particle sizes. Also, the coatings contained about 1.0-2.5 vol.% surface micropores. However, the comparison between the trend of the surface roughness and the quantity of surface pores did not show direct correlation. Composition analysis of the coatings revealed the uniform dispersion of CNTs within the coatings.
10.1016-j.apsusc.2014.05.067	-1		A lightweight multi-layered electromagnetic interference (EMI) shielding material made of open-cell foam of a Cu-Ni alloy integrated with carbon nanotubes (CNTs) was prepared by electroless copper plating, then nickel electroplating, and finally electrophoretic deposition of CNTs. The foamed Cu-Ni-CNT composite comprises, from inside to outside, Cu, Ni, and CNT layers. Scanning electron microscopy, energy dispersive spectroscopy, and EMI tests were employed to characterize the morphology, composition, and EMI performance of the composite, respectively. The results indicated that the shielding effectiveness (SE) of the composite increased with increasing pore density (indicated as pores per inch (PPI)) and increasing thickness. A specimen with a PPI of 110 and a 1.5-mm thickness had a maximum SE of up to 54.6 dB, and a SE as high as 47.5 dB on average in the 8-12 GHz range. Integrating the inherent superiority of Cu, Ni, and CNTs, the porous structure of the composite can attenuate the incident electromagnetic microwaves by reflecting, scattering, and absorbing them between the metallic skeleton and the CNT layer. The multiple reflections and absorptions make it difficult for the microwaves to escape from the composite before being absorbed, thereby making the composite a potential shielding material.
10.1016-j.apsusc.2014.05.141	-1		Three Cu-Mo-Si coatings were synthesized on steel using laser cladding. The coatings have dense microstructure with composite phases including metal silicates and Cu-based solid solution. Different alloy compositions reduce different phases generated in the coatings. Phases appeared in three coatings were Cu + MoSi2 + Mo5Si3 + Cu3Si (Coatings 1 and 2), Cu + Mo3Si + Mo5Si3 + Cu3Si (Coating 3), respectively. The microhardness of coatings is in the range of 600 to 900 HV. The amount of Mo5Si3 phase decides the hardness of Cu-Mo-Si coatings in laser processing. The proof is that the highest hardness which is about 900 HV occurs in the clad layer of Coating 1. The thickness of clad layer of three coatings is about 0.7 mm (Coating 1), 0.8 mm (Coating 2) and 1.0 mm (Coating 3), respectively. The average friction coefficient for Coatings 1-3 is 0.40, 0.56 and 0.60, respectively. Wear rate values of 2.9 x 10(-6) g/N m (Coating 1), 3.1 x 10(-6) g/N m (Coating 2) and 3.5 x 10(-6) g/N m (Coating 3) are calculated, respectively. The amount and kind of metal silicates have a huge influence on the wear resistance of coatings.
10.1016-j.apsusc.2014.06.078	16	wear; composite; composites; powders; milling; particles; powder; wt; sliding; friction; hardness; matrix; mechanical; surface; properties	A comparative assessment in terms of uniformity, coating coverage and coating deposition mechanism has been carried out for two different types of Cu-Sn coatings on steel substrate with varying Sn composition (2-6.5 wt%) deposited via immersion technique, viz. (i) single layer Cu-Sn coating and (ii) double layer coating consisting of a thin Cu strike layer followed by a Cu-Sn layer. Coating morphology, surface coverage, coating-substrate interface, and coating composition at surface and along the depth were studied using laser confocal microscope (OLS), scanning electron microscope (SEM) coupled with energy dispersive spectroscope (EDS), glow discharge optical emission spectroscopy (GDOES), X-ray photoelectron spectroscopy (XPS) and cross-sectional transmission electron microscopy (TEM). Quantitative depth profiling using GDOES and surface compositional analysis via XPS suggested improvement in surface coverage in the case of double layer coatings. SEM-EDS and TEM analysis confirmed that the coating deposition was more uniform with sufficient coating penetration inside the deep roughness troughs resulting in compact and micro-porosity free interface for this type of coatings. Better adhesion strength with less variation in peel force and cohesive mode of fracture within the rubber was observed for the double layer coated samples during the peel test carried out on coated steel samples vulcanized with rubber. On the other hand, the single layer coated samples showed large variation in peel force with adhesive-cohesive or mixed mode of fracture at interface.
10.1016-j.apsusc.2014.09.069	2	corrosion; surface; film; electrochemical; films; spectroscopy; layer; current; solution; potential; resistance; composition; x-ray; ions; showed	Copper and silver are used as antimicrobial agents in the healthcare sector in an effort to curb infections caused by bacteria resistant to multiple antibiotics. While the bactericidal potential of copper and silver alone are well documented, not much is known about the antimicrobial properties of copper-silver alloys. This study focuses on the antibacterial activity and material aspects of a copper-silver model alloy with 10 wt% Ag. The alloy was generated as a coating with controlled intermixing of copper and silver on stainless steel by a laser cladding process. The microstructure of the clad was found to be two-phased and in thermal equilibrium with minor Cu2O inclusions. Ion release and killing of Escherichia coli under wet conditions were assessed with the alloy, pure silver, pure copper and stainless steel. It was found that the copper-silver alloy, compared to the pure elements, exhibited enhanced killing of E. coli, which correlated with an up to 28-fold increased release of copper ions. The results show that laser cladding with copper and silver allows the generation of surfaces with enhanced antimicrobial properties. The process is particularly attractive since it can be applied to existing surfaces.
10.1016-j.apsusc.2014.10.021	16	wear; composite; composites; powders; milling; particles; powder; wt; sliding; friction; hardness; matrix; mechanical; surface; properties	Cu-4.1Zr-1.1B (wt%) composite has been synthesized by mechanical alloying, cold pressing of mechanically alloyed powders and, for the first time in literature, sintering by laser irradiation (pulsed, millisecond Nd: YAG laser was employed) in nitrogen atmosphere. The influence of different sintering parameters on the properties of laser-sintered materials was investigated. Microstructural changes during laser sintering were studied using scanning electron microscopy and X-ray diffraction. Rapidly solidified structure, as well as the presence of ZrB2 particles and metastable CuZr phase, which are a product of laser sintering, affected higher degree of copper matrix hardening which was retained up to high temperatures. In general, laser sintering of Cu-4.1Zr-1.1B (wt%) green compact using the parameters: laser frequency 3 Hz, laser pulse duration 8 ms, pulse energy similar to 19 J, number of scans 4 yields the optimum combination of high density, microhardness and electrical conductivity.
10.1016-j.apsusc.2015.02.005	2	corrosion; surface; film; electrochemical; films; spectroscopy; layer; current; solution; potential; resistance; composition; x-ray; ions; showed	The galvanostatic technique was used to analyze the electrodeposition of Cu-Zn on to AISI 1010 steel electrode from an alkaline-sorbitol bath with various proportions of the metal ions in the bath: Cu70/Zn30, Cu50/Zn50 and Cu30/Zn70. Coloration of Cu-Zn films were whitish golden, light golden, golden/gray depending on the Cu2'/Zn2+ ratios in the electrodeposition bath, deposition current density (jd,) and charge density (qd). The highest current efficiency was -54.0%, atjd -1.0 mA cm -2 and qd 0.40 C cm -2 in the Cu70/Zn30 bath . Energy dispersive spectroscopy indicated that electrodeposits produced from the bath Cu70/Zn30 showed higher Cu content at lower jd. Also, for same jd the Cu content increased with qd,. Scanning electron microscopy showed that Cu-Zn electrodeposits of high quality were obtained from the Cu70/Zn30 bath, since the films were fine-grained, except the obtained at jd, -20.0 mAcm-2 and qd, 10.0 C cm -2. Also, these electrodeposits did not present cracks. X-ray analysis of the Cu-Zn electrodeposits obtained at jd, -8.0, -20.0 and -40.0 mA cm-2, in each case, with qd, 2.0 and 10.0 C cm-2, in the Cu70/Zn30 bath, suggested the occurrence of a mixture of the following phases, CuZn, CuZn5 and Cu5Zn8. Galvanostatic electrodeposits of Cu-Zn obtained from sorbitol-alkaline baths exhibited whitish golden color, with good prospects for industrial applications, especially for decorative purposes.
10.1016-j.apsusc.2015.06.189	-1		Dependence of characteristics of surface BeO layer and secondary electron emission properties of a Cu-Be alloy on activation conditions were studied by measurements of X-ray photoelectron spectroscopy and secondary electron yield of the alloy based on varying conditions of an optimized activation treatment. The results showed that the thickness and composition distribution of the surface BeO layer of the alloy were closely related to the pre-heat treatment and the affecting factors (oxidation duration, oxidation temperature, and oxygen pressure) of the oxidation process in the activation treatment. The improper treatment leaded to a too thick or too thin surface BeO layer, the presence of metallic Be, and poor distribution of metallic and oxidized Cu in the layer, hence significantly reduced the secondary electron emission yield of the activated Cu-Be alloy.
10.1016-j.apsusc.2017.01.080	2	corrosion; surface; film; electrochemical; films; spectroscopy; layer; current; solution; potential; resistance; composition; x-ray; ions; showed	Naturally grown patinas are typically detected onto the surface of modern copper-based artefacts and strictly affect their surface reactivity and appearance. The production of representative patinas is a key issues in order to obtain model systems which can be used for the development and validation of appropriate conservation materials and methods. In this study, we have prepared different artificial representative patinas by using a quaternary Cu-Sn-Zn-Pb alloy with chemical composition and metallurgical features similar to those of valuable modern works of art. In order to produce degradation products usually observed onto their surface, chloride and sulphate species were used to induce corrosion processes. Different patinas were produced by changing the nature of corrosive species and the set-up for the accelerated degradation. The composition and structural properties of the patinas were investigated by attenuated total reflectance Fourier transform infrared spectroscopy, X-ray diffraction, optical microscopy and scanning electron microscopy combined with energy dispersive X-ray spectroscopy. The results allow to identify degradation products and to distinguish copper hydroxychloride polymorphs and copper hydroxysulphates with similar structure. Our findings show that patina composition can be tailored by modifying the degradation procedure and patinas representative of modern artefacts made of quaternary Cu-Sn-Zn-Pb alloy can be obtained. (C) 2017 The Authors. Published by Elsevier B.V
10.1016-j.apsusc.2017.01.182	2	corrosion; surface; film; electrochemical; films; spectroscopy; layer; current; solution; potential; resistance; composition; x-ray; ions; showed	High corrosion resistant Cu-Co-P coatings were firstly prepared on polyethylene terephthalate (PET) substrate by electroless plating in combination with UV/ozonolysis irradiation under optimized cobalt sulfate heptahydrate concentration, pH value, plating temperature and time. The copper polyalloy/PET composite can be obtained in three steps, namely: (i) the generation of oxygen-containing functionalities (carboxylic groups) onto PET surface through UV irradiation combined with ozone, (ii) Cu seeding catalysts were obtained after being immersed into cupric citrate and NaBH4 solutions subsequently, and (iii) Cu-Co-P polyalloy metallization using electroless plating bath . Attenuated total reflection fourier transformation infrared spectrometer (ATR-FTIR), X-ray photoelectron spectroscopy (XPS), water contact angle measurement and energy dispersive X-ray analysis (EDAX) were utilized to track the surface changes during the whole process. The electroless plating conditions were optimized by an orthogonal experiment (L-9(3)(4)) for Cu-Co-P coating as follows: CoSO4 center dot 7H(2)O addition of 0.08 M, pH value, plating temperature and time were set on 10.0, 35 degrees C and 25 min, respectively. Under the optimal conditions, copper polyalloy possessed high adhesive strength and the lowest surface resistance (8.06 Omega/sq), while maintaining reliability even after over 1000 times of bending and mechanical stress. The results of scanning electron microscope (SEM) and atomic force microscope (AFM) measurements showed that Cu-Co-P layer formed on PET surface was imparted with fine uniformity and high compactness. Electrochemical test revealed the optimized Cu-Co-P coatings exhibited high corrosion resistance in NaCI, NaOH and HCI solutions, respectively. The excellent electromagnetic interference shielding effectiveness (EMI SE >99.999% at frequency ranging from 30 MHz to 1000 MHz) of copper polyalloy/PET composites was confirmed by the spectrum analyzer. Therefore, this copper polyalloy will have potential applications in microelectronics packaging and coatings for anti-corrosion and electromagnetic interference shielding.
10.1016-j.apsusc.2017.01.192	-1		We have measured surface energy in two-component Cu-based systems in H-2 + Ar gas atmosphere. The experiments on solid Cu [Ag] and Cu [Co] solutions show presence of phase transitions on the surfaces. Isotherms of the surface energy have singularities (the minimum in the case of copper solid solutions with silver and the maximum in the case of solid solutions with cobalt). In both cases, the surface phase transitions cause deficiency of surface miscibility: formation of a monolayer (multilayer) (Cu-Ag) or of nanoscale particles (Cu-Co). At the same time, according to the volume phase diagrams, the concentration and temperature of the surface phase transitions correspond to the solid solution within the volume. The method permits determining the rate of diffusional creep in addition to the surface energy. The temperature and concentration dependence of the solid solutions' viscosity coefficient supports the fact of the surface phase transitions and provides insights into the diffusion properties of the transforming surfaces.
10.1016-j.apsusc.2017.06.021	-1		We report the high-yield and large-area synthesis of a spaghetti-like carbon nanotubes (CNTs) on macroscopic Cu substrates (foil and foam) using a Cu-Sn alloy catalyst. In addition, we investigate the corrosion properties of the as-synthesized CNT/Cu foil system in 0.6 M NaCl solution. Electrochemical analysis showed that the corrosion resistance of the CNT/Cu foil system improved by a factor of similar to 100 compared to the as-received Cu foil. Thus, it is concluded that a dense network of CNT was uniformly coated on the Cu foil and this coating functioned as an efficient barrier to corrosion under simulated seawater conditions.
10.1016-j.apsusc.2017.06.049	-1		In this paper, tungsten (W) was chosen to be an alloying element into the surface layer of commercial pure (cp) copper (Cu) to enhance the surface properties after surface alloying by high current pulsed electron beam (HCPEB). After HCPEB irradiation, part of the blended powder was dissolved into the substrate surface to form an alloyed layer, which has defect structures consisting of dislocation cellws/walls. The presence of defect structures induced by HCPEB irradiation provides a large amount of paths for W atoms to form solid solution and ultrafine W particles. The surface hardening is ascribed to intense plastic deformation via stress, sub-grain strengthening, along with the alloying elements via precipitation hardening and/or the solid solution strengthening. The corrosion performance, tested in 3.5% NaCl solution, was significantly enhanced after surface alloying. The improvement in corrosion resistance is essentially attributed to the combination of the structure defects and the addition of alloying elements to form more stable passive film.
10.1016-j.apsusc.2017.08.017	-1		Copper-carbon alloy films have been applied in barrier-less Cu metallization as seed layers for improving the thermal stabilities. The effect of the deposition temperature on the microstructure and properties of C-doped Cu films on Si substrates was investigated. The films were prepared by ion beam-assisted deposition at various deposition temperatures by co-sputtering of Cu and graphite targets. No inter-diffusion between Cu and Si was observed in Cu(C) films throughout this experiment, because XRD patterns corresponding to their deep-level reaction product, namely, Cu3Si, were not observed in XRD patterns and EDS results of Cu(C) films. Amorphous carbon layer and SiC layer were found in the interface of Cu(C) as-deposited films when deposition temperature rose to 100 degrees C by TEM, high-resolution image and Fourier transformation pattern. The Cu(C) films deposited at 100 degrees C had the best thermal stabilities and the lowest electrical resistivity of 4.44 mu W cm after annealing at 400 degrees C for 1 h . Cu agglomeration was observed in Cu(C) alloy films with deposition temperatures of 200, 300 and 400 degrees C, and the most serious agglomeration occurred in Cu(C) films deposited at 200 degrees C. Undesired Cu agglomeration resulted in a sharp increase in the resistivity after annealing at 300 degrees C for 1 h . The deposition temperature of 100 degrees C reflected the superior thermal stabilities of Cu(C) seed layers compared with those of other layers.
10.1016-j.apsusc.2017.11.198	-1		Systematic investigation of microstructure in pseudo-binary alloys of (Cu2Te)(x)-(Sb2Te3)(100-x) (x = 11.91, 32.60, 50.0, 62.02, 73.95, 85.50, 95.65) and their thermoelectric properties had been studied. Alloys were prepared by solid-state synthesis method. Powder X-ray diffraction confirmed the presence of Cu2Te and Sb2Te3 phases which were supported by results of electron probe microanalysis. Scanning electron micrographs of (Cu2Te)(62.02)-(Sb2Te3)(37.98) showed eutectics which are predominantly rod-like with a small amount of degenerate eutectics at the boundaries. The microstructure of hypereutectic alloys comprises of Sb2Te3 major phase along with Cu2-delta Te minor phase whereas hypoeutectic alloys consist of eutectic and Cu2Te proeutectic constituent. Transport properties were measured in the temperature between 350 and 600 K. Temperature dependent electrical conductivity (sigma) for all samples showed metal-like behavior. Positive Seebeck coefficients (S) indicate that majority carriers were holes. A systematic decrease in S and increase in sigma with Cu content was due to an increase of carrier concentration caused by the easy formation of Cu vacancies in Cu2-delta Te. A different trend of temperature-dependent thermal conductivity for hypoeutectic, hypereutectic and eutectic alloys could be due to the influence of composition and/or microstructure variation. The most striking results of the present investigation is the significant improvement of high temperature figure of merit of Sb2Te3 with small addition of Cu2Te (similar to 11%) with a value of zT of 0.6 at 600 K coupled with an increase mechanical strength as reflected by the increase in hardness.
10.1016-j.apsusc.2018.01.018	-1		Low energy electron emission microscopy (LEEM) was used to measure local transition energy that was directly correlated to electron work function (EWF) of multiphase manganese-aluminum bronze alloys. We developed color mapping to distinguish the EWF of multiple phases and clarified that the EWF were in the following order: EWF of alpha > EWF of beta > EWF of kappa (EWF alpha > EWF beta > EWF kappa). De-alloying corrosion took place due to the micro-galvanic cell at grain boundaries before it propagated into the beta phase that had lower EWF than the alpha phase. The alpha phase was a stable phase because it contained high Cu while the beta phase contained high Al and Mn. In addition, XRD analysis showed that the texture coefficient of the b phase revealed that almost all of the grains had (2 2 0) orientation, the lowest EWF compared to (1 1 1) and (2 0 0). Furthermore, transmission electron microscopy illustrated that there were fine Cu3Mn2Al precipitates in the Cu2MnAl matrix of the beta phase. These precipitates formed micro-galvanic cells which played an important role in accelerating de-alloying corrosion.
10.1016-j.apsusc.2018.01.035	-1		The major bottleneck in developing graphite fiber reinforced copper (GF/Cu) composites is the poor wettability of Cu/graphite system. Alloying element of chromium (Cr) is introduced to improve the wettability of liquid copper on graphite. Sessile drop method experiments illustrate that the contact angle of liquid Cu-Cr (1.0 wt%) alloy on graphite substrate decreases to 43 degrees at 1300 degrees C. The improvement of wettability is related to the formation of chromium carbide layer at interface zone. Based on the wetting experiment, a spontaneous infiltration method for preparing GF/Cu composites is proposed. Unidirectional GF preforms are infiltrated by Cu-Cr alloys without external pressure in a tubular furnace. Results reveal that the GF preform can be fully infiltrated by Cu-Cr alloy (8 wt%) spontaneously when fiber volume fraction is 40%. The coefficient of thermal expansion (CTE) of GF/Cu-Cr (8.0 wt%) composites is 4.68 x 10(-6)/K along the longitudinal direction.
10.1016-j.apsusc.2018.01.116	2	corrosion; surface; film; electrochemical; films; spectroscopy; layer; current; solution; potential; resistance; composition; x-ray; ions; showed	The evolution of the corrosion process on Cu-Ni-Zn alloy in alkaline chloride solution was investigated by in-situ scanning electrochemical microscopy, X-ray photoelectron spectroscopy, and ex-situ laser confocal microscopy, and the effects of ambient temperature and polarization time were also discussed. The results demonstrated a higher pitting nucleation rate and lower pit growth rate at low temperature. The ratio of pit depth to mouth diameter decreased with increasing pit volume and temperature, indicating that pits preferentially propagate in the horizontal direction rather than the vertical direction owing to the presence of corrosion products and deposited copper. The surface current was uniform and stabilized at approximately 2.2 nA during the passive stage, whereas the current increased after the pits were formed with the maximum approaching 3 nA. Increasing the temperature led to an increase in porous corrosion products (CuO, Zn(OH)(2), and Ni(OH)(2)) and significantly increased the rate of transition from pitting to uniform corrosion. Dezincification corrosion was detected by energy dispersive spectrometry, and a mechanism for pitting transition into uniform corrosion induced by dezincification at the grain boundaries is proposed.
10.1016-j.apsusc.2018.02.262	-1		The microstructure, electrical resistivity and thermal conductivity of the sputtering deposited Cu-Ta films were investigated as a function of Ta content. The results showed that the amorphous phase formed between 20 at% and 60 at% Ta, and out of this range alpha-Cu(Ta) and beta-Ta(Cu) solid solutions formed. Because the lattice distortion and beta-Ta structure could significantly increase the probability of electron scattering, the electrical resistivity of the Cu-Ta films shows a 'N' type change with the increase of Ta content, and the inflection point appears at 50 at% Ta and 60 at% Ta respectively. As the thermal conductance is also dominated by electrons in metals films, an opposite variation tendency is found in the thermal conductivity of the Cu-Ta films. According to our knowledge, this is the first time to measure the thermal conductivity of Cu-Ta thin films.
10.1016-j.apsusc.2018.05.130	16	wear; composite; composites; powders; milling; particles; powder; wt; sliding; friction; hardness; matrix; mechanical; surface; properties	In this paper, electrodeposition process was used for deposition of copper based mull-walled carbon nanotubes (MWCNTs) nanocomposite coating on 6061 aluminium in order to enhance the electrical and thermal properties. The method of anodization of aluminium alloy was applied prior to plating to get highly adherent Cu-MWCNT composite coating. Ammonium bi-fluoride (NH4F center dot HF), a fluorine-containing inorganic substances was added to the anodized solution to increase the porosity of the anodized aluminium alloy surface. Cetyl Tri-methyl Ammonium Bromide (CTAB) cationic surfactant was added in electrolytic bath to get stable, colloidal and uniform dispersed MWCNT copper sulphate solution. The characterization and compositional analysis of the developed Cu-MWCNT composite coating was investigated by scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDS) and x-ray diffraction (XRD). The electrical and thermal conductivity were measured for the pure copper coated and Cu-MWCNT nanocomposite coated samples, respectively. It was found that incorporation of MWCNTs in the copper coatings enhanced the electrical conductivity by 59.63%, 103.67% and 128.44%, respectively for Cu-MWCNT (0.5 gL(-1), 0.75 gL(-1) and 1 gL(-1), respectively) nanocomposite coated specimens compared to pure copper coated specimen. The thermal conductivity of Cu-MWCNTs (0.5 gL(-1)) composite coated sample was improved by 95.62% compared to uncoated 6061 aluminium specimen.
10.1016-j.apsusc.2018.06.029	2	corrosion; surface; film; electrochemical; films; spectroscopy; layer; current; solution; potential; resistance; composition; x-ray; ions; showed	Pure copper, tin copper and beryllium copper were exposed to a harsh marine environment, and the effects of fin and beryllium addition on copper corrosion were systematically investigated and compared. The corrosion rate for pure copper was similar with that for tin copper, but significantly higher than that for beryllium copper, indicating an improvement in corrosion resistance due to the addition of beryllium. Pitting corrosion occurred in all investigated materials and the extent of pitting damage was in the order of pure copper > tin copper > beryllium copper. Flaking corrosion was prominent on fin copper plate after long-term exposure and the primary corrosion products in all materials were Cu2O, CuCl and Cu2Cl(OH)(3). The tin content in the inner corrosion layer was higher than in the outer layer for tin copper, whereas beryllium accumulated at the outer layer of beryllium copper, confirmed by auger electron spectroscopy, and related corrosion mechanisms were proposed.
10.1016-j.apsusc.2018.11.144	2	corrosion; surface; film; electrochemical; films; spectroscopy; layer; current; solution; potential; resistance; composition; x-ray; ions; showed	The corrosion products naturally formed on archaeological Cu-based artefacts during their long-term exposure to seawater have been investigated in details by means of X-ray diffraction (XRD), scanning electron microscopy coupled with energy dispersive spectrometry (SEM + EDS), optical microscopy (OM), attenuated total reflectance Fourier transform infrared spectroscopy (ATR-FTIR), differential thermal analysis-thermogravimetry (DTA-TG), inductively coupled plasma mass spectrometry (ICP-MS) and X-ray photoelectron spectroscopy (XPS). The bronze artefacts include fragments of valuable statues and objects that were retrieved some decades ago from different seabeds along the Italian coast of the Mediterranean basin including the so called Punta del Serrone area (Apulia), the Sicilian channel (Sicily) and the Arburese coast (Sardinia). Our findings show that the alloy matrix is often heavily corroded also in the bulk and reveal the dangerous presence of chlorine from seawater as main dangerous corrosive agent. Chlorine is present as copper nantokite (CuCl) in the inner layers of the patina and is potentially inducing with oxygen and moisture the cyclic and often relentless copper degradation phenomenon commonly called bronze disease. The most common corrosion products are also lead carbonate (cerussite, PbCO3) and aragonite (CaCO3), likely related to the large abundance of CO2 in the seawater where is assimilated much more than in fresh water. Furthermore, the results reveal that other environmental elements contributing to the composition of the patina are sulphur, magnesium and phosphorous thus giving rise to a patina with a chemically and structurally complex structure. The results reveal also the contribution of bio-organism to the formation of the patina as supported by the presence of vanadium and copper sulphides. These information allow, as a whole, to propose a tentative correlation between the patina's nature, the chemical composition and metallurgical features of the alloys and the marine environment where the objects lived for about two thousands years. From a conservation point of view, the findings reported in this work can provide some insights useful to tailor more efficient conservation strategies with the purpose to ensure a long-term chemical-physical stability to the bronze artefacts.
10.1016-j.apsusc.2019.05.068	16	wear; composite; composites; powders; milling; particles; powder; wt; sliding; friction; hardness; matrix; mechanical; surface; properties	Present work investigated the use of Cold Metal Transfer (CMT) welding for additive manufacturing of copper-aluminum alloys with addition of silicon in small amount. The additive manufacturing was successfully demonstrated through two samples with the 4.34% (sample-1) and 6.58% (sample-2) aluminum content, which is not much different with the content of the design. The analyses of performance of samples reveal that both samples have good strength and ductility. It is also found addition of silicon in small amount (2.1%-2.4%) effectively improves hardness, tensile strength and 0.2% offset Yield Strength in comparison to pure coppera-luminum alloy. The results of X-ray diffraction (XRD), showed that sample-2 possessed CuAl2 with different crystal structure whereas sample-1 did not. It is found that an increase in aluminum caused both tensile strength and 0.2% offset Yield Strength to increase, however, increase in yield strength was very significant (155 MPa i. e. 38% more than that of Sample-1). In this study, the 0.2Pct offset Yield Strength of sample-1 is 150 MPa more than that of sample-2.
10.1016-j.apsusc.2020.146816	-1		Surface engineering via alloying opens up a new route to tune the strength of an alloy film, thus it is critical to determine an optimal alloy addition. Here, the effect of varying the content of extremely dilute manganese oxide (MnO), namely 0.04, 0.10 and 0.17%, on microstructure stability and reliability of electroless plated colloidal Cu alloy thin films upon annealing is studied. An intermediate MnO content (0.10%) noticeably gives the best performance in terms of stabilizing Cu grains and enhancing film reliability against thermal stressing. Transmission electron microscopy and secondary ion mass spectroscopy reveal that the strengthening mechanism is related to interfacial segregation of MnO (serving as a barrier) and grain-boundary segregation of MnO (pinning and stabilizing Cu grains). However, the stabilization of Cu grains by the segregation of MnO are both missing from the other two films with MnO additions of 0.04% and 0.17%, and an identical annealing thus leads to their premature failure. Thin-film properties of adhesion strength, residual stress, surface energy, and MnO segregation tendency are comprehensively studied elucidating the strengthening mechanism.
10.1016-j.apsusc.2020.148820	2	corrosion; surface; film; electrochemical; films; spectroscopy; layer; current; solution; potential; resistance; composition; x-ray; ions; showed	Laser ablation is an effective method to clean Cu-based alloys. A novel procedure of characterisation was developed involving O-18 isotopes evaluated by ToF-SIMS spectroscopy to assess the driving mechanisms of laser-surface interactions. The presence of re-oxidised compounds was detected, discerning between the oxygen from the corrosion layer and the one introduced by the interaction with the laser (that was generated in a controlled atmosphere of O-18 diluted in N-2). A set of samples treated with different laser conditions were characterised by FESEM and mu Raman. The results have shown that re-oxidation phenomenon can occur and its selectivity depends on the laser conditions.
10.1016-j.apsusc.2021.150672	-1		In this paper, an efficient fabrication route is presented for carbon-coated Cu-Ni alloy nanoparticles (Cu1-xNix@C NPs; x = 0-1.0) by means of electrical wire explosion under methane gas. The Cu-Ni binary system, which is considered to be an ideal isomorphous system, has carbon growth controllable by tuning the atomic fraction of Cu and Ni with largely different carbon solubility. As the Ni content increases, the average particle size and carbon layer thickness increase. It is notable that the carbon layer is very thin, <2 nm, regardless of the core size for pure Cu@C NPs. On the other hand, as the Ni content increases, the particle size dependence of the carbonlayer thickness becomes significant and the carbon layer is obviously tunable from amorphous to crystalline form. The high-temperature oxidation stability of Cu1-xNix@C NPs is enhanced with increasing Ni content due to the higher thermal stability of carbon layers with greater thickness and high crystallinity. The conductive films were prepared using screen-printing of paste containing Cu1-xNix@C NPs and the electrical resistivity was mapped according to the Ni content. The temperature stability of the sheet resistance and activation energy of oxidation for the conductive films increase with increasing Ni content.
10.1016-j.apsusc.2021.151602	-1		Cu-Zn based alloys have been widely used in various applications due to their outstanding properties, such as high electrical conductivity and increased hardness over pure Cu. The thermal effect during electrical conduction leads to the requirement of excellent thermal stability for maintaining performance, which is strongly related to the microstructural transformation and kinetics. However, the atomic-scale microstructural evolution of Cu-Zn systems has scarcely been discussed. In this study, the reaction process of Cu-Zn systems was observed via in situ high-resolution transmission electron microscopy (in situ HRTEM). The Zn/Cu thin films were converted to 13-CuZn at 180 degrees C and exhibited an epitaxial relationship with Cu, which was described as (01 1)13-CuZn // (111)Cu and [10 0]13-CuZn // [11 0]Cu. Subsequently, the Cu-rich solid solution (alpha phase) was formed at 300 degrees C to decrease the Gibbs free energy, where layer-by-layer diffusion took place on the (11 1) plane. Based on the improved twinnability of the alpha phase with decreasing stacking fault energy (SFE), nanotwins grew along with the alpha phase. The twin boundaries effectively retard atomic migration, which is expected to optimize the mechanical properties. The fundamental science described in this study provides novel insights into Cu-Zn alloys, which could be explored in a wide range of alloy systems.
10.1016-j.apsusc.2021.151623	16	wear; composite; composites; powders; milling; particles; powder; wt; sliding; friction; hardness; matrix; mechanical; surface; properties	The evolution of microstructure and mechanical properties in as-cast Cu-12Sn-1.5Ni-(0-1.5)Fe (wt. %) alloys was investigated in the previous work. Herein, the effect of minor Fe (0, 0.053, 0.63 wt%) addition on wear behavior of the alloy surface was explored. The coefficient of friction (COF) (0.61 to 0.51 at load of 10 N, 0.67 to 0.42 at 5 N) and wear rate (42.0 x 10(-5) to 23.1 x 10(-5) mm(3)/(N.m) at 10 N, 18.7 x 10(-5) to 3.6 x 10(-5) mm(3)/(N.m) at 5 N) decreased with addition of Fe. A transition in wear mechanisms was noticed with applied load. Abrasion wear was the dominant mechanism at 10 N together with slight oxidative wear, while adhesion and tribo-oxidation mechanisms controlled the wear at 5 N. The delamination and wear debris on worn surfaces lessened with increasing Fe both at 10 and 5 N, in line with the variation in COF and wear rate. The mechanisms underlying the improved wear behavior were evaluated in terms of microstructural optimization, densification and enhancement in mechanical properties. This work indicates the advantage of minor amount of Fe addition to achieve better wear resistance of nickel bronze alloys.
10.1016-j.apsusc.2022.154892	-1		Cu-Mo-Zr alloy films with different Zr contents were prepared by magnetron sputtering. The microstructure and SERS properties of alloy films were characterized by SEM, TEM, XRD and Raman spectroscopy. A large number of Cu nanoparticles are formed spontaneously on the surface of alloy film after annealing. Moreover, the number, size and particle spacing of Cu nanoparticles are found to be highly sensitive to annealing temperature, annealing time, Zr content and film thickness. Results of the local electric field between Cu particles on the alloy films surface simulated by FDTD reveal that larger particles and smaller spacing can produce stronger local electric fields. Furthermore, a 10 nm Ag layer coating on the alloy film has a significant effect on the size, spacing of Cu particles, and the synergistic enhancement between Ag layer and Cu nanoparticle can significantly increase the local electric field thereby improving the SERS performance of Cu-Mo-Zr alloy films. The Raman signal of 10-13 mol/L Rhodamine 6G solution can be detected by using Ag layer/Cu-30 at% Mo-22.9 at% Zr alloy films as SERS substrates. The present study provides a method for preparing SERS substrates with low cost, high sensitivity and excellent repeatability.
10.1016-j.apsusc.2023.158298	2	corrosion; surface; film; electrochemical; films; spectroscopy; layer; current; solution; potential; resistance; composition; x-ray; ions; showed	The aim of the present research is to develop one new strategy to modify the brass surface with well anticorrosion performance. Here, utilizing the synergistic effect between thioglycolic acid (TGA) and Y(III), one organic-inorganic hybrid film composed of a self-assembled film at the top and an oxide film at the bottom was fabricated on brass surface. The formation process of the hybrid film contained the parallel adsorption of TGA molecules, surface oxidation of copper accompanied by zinc dissolution, interface deposition of Y2O3 and assembly of Cu-TGA chelates. Electrochemical results indicated that the protection efficiency was 99.2% under the optimum conditions and the value remained at 92.1% after 12 h immersion in 3.5 wt% NaCl solution. Due to the good water solubility of the film-forming substance and excellent anticorrosion performance of the fabricated film, this strategy has important application potential in the field of surface functionalization of copper alloys.
10.1016-j.apsusc.2023.158967	-1		Direct printing of flexible Cu traces is one of the most promising additive manufacturing technologies in advanced electronics because it is a cost-effective and environmentally friendly process. However, the low oxidation resistance of Cu is currently a critical issue for the preparation of high-performance metallic inks and the manufacturing of reliable printed traces. Herein, we propose a hybrid ink containing Cu/Ni complexes and Cu particles that can be directly printed onto polyimide substrates to generate high-performance Cu-Ni alloy traces by low-temperature preheating and intense pulsed-light irradiation. The nanoparticles in-situ formed by the decomposition of the complexes effectively bridge the interfaces among Cu particles, allowing the printed traces after subsequent intense pulsed-light irradiation to achieve a low resistivity of 29.4 mu omega & sdot;cm and excellent mechanical stability at a bending radius of 7 mm. Strikingly, the obtained Cu-Ni alloy traces achieve multiscale core-shell structures because of the heterogeneous nucleation and passivation of Ni, which enables the printed traces to maintain high conductivity and oxidation resistance even at 250 degrees C in the air, showing strong potential for use in advanced electronics manufacturing.
10.1016-j.apsusc.2023.158972	2	corrosion; surface; film; electrochemical; films; spectroscopy; layer; current; solution; potential; resistance; composition; x-ray; ions; showed	Marine biofouling is a key issue that deteriorates the service performance and lifespan of ships and underwater engineering structures. The development of effective and long-term antifouling coating material is significant but still poses a great challenge. Herein, we have proposed the Cu-Cr cladding layers containing submicron Cr-rich precipitated phases were prepared via laser cladding technology. The cladding layers were aimed to ensure the continuous release of copper ions through the micro-galvanic cells by promoting Cu2(OH)3Cl flaking, and thus achieve effective and long-term antifouling performance. The effect of Cr content on corrosion behavior and antifouling performance of Cu-Cr cladding layers in a simulated seawater environment was investigated. The results demonstrated that corrosion and copper ions release rates increased while the P. tricornutum coverage rate decreased with the increase in the Cr content. It was associated with the increase of Cr-rich precipitates accel-erating the corrosion of Cu-rich matrix within micro-galvanic cells. Importantly, the increased accumulation of Cr2O3-rich particles intensified the loose and cracked Cu2(OH)3Cl flaking, ensuring the long-term continuous release of copper ions from the cladding layer and thus achieving effective antifouling performance.
10.1016-j.apsusc.2024.160585	2	corrosion; surface; film; electrochemical; films; spectroscopy; layer; current; solution; potential; resistance; composition; x-ray; ions; showed	Tolyltriazole (TTAH) is used industrially as a corrosion inhibitor for copper alloys, particularly in organic media. In this study, the morphology and chemistry of the layer formed by TTAH on copper and copper alloys under realistic conditions is investigated, with focus on the effects due to the presence of tin or zinc in the substrates. A combination of X-ray photoelectron spectroscopy (XPS), medium energy ion scattering (MEIS), and scanning transmission electron microscopy (STEM) has been used. It was found that an inhomogeneous metal-organic layer forms on the surface of copper specimens, likely in the form of copper nanoparticles surrounded by Cu x TTA y complexes. This layer increases in thickness for at least 30 days. Chemically, the copper species in the layer are initially in the +2 oxidation state, but after longer exposure to TTAH, mostly Cu(I) is observed. In bronze samples, tin does not appear to segregate to the surface layer. In brass samples, zinc is depleted from the bulk and forms a thicker Zn x TTA y layer.
10.1016-j.apsusc.2024.162232	2	corrosion; surface; film; electrochemical; films; spectroscopy; layer; current; solution; potential; resistance; composition; x-ray; ions; showed	The adsorption behaviour and corrosion inhibition mechanism of 2-aminobenz- imidazole (2-ABI) on Cu-5 wt% Fe (Cu-5Fe) alloys was investigated by in-situ observation and scanning kelvin probe force microscopy (SKPFM). The 2-ABI molecules adsorb only on the cathode Cu phase and forms a protective film, while the anode Fe phase is barely dissolved after long-term immersion, corresponding to the inhibition efficiency reaching 92.7 % after 72 h immersion. The Volta potential difference between the Cu matrix and Fe phases increased from 41 to 145.4 mV due to the lack of electrical conductivity in the 2-ABI adsorption film on the Cu matrix. Hence, the 2ABI adsorption film prevents the formation of micro-galvanic couples and eventually alters the corrosion mechanism of the Cu-5Fe alloy.
10.1016-j.apsusc.2025.162395	-1		Nanoscale metallic multilayers (NMMs) are essential in micro/nanodevices because of their superior physical and mechanical properties. Differing from tension and compression, NMMs exhibit inhomogeneous localized plastic deformation during shear rather than a uniform overall strain response. The shear responses and deformation mechanisms of Cu/Ta NMMs at various temperatures are studied by molecular dynamics simulations. The results show the interfacial atomic structures get more disordered with increasing temperature. There are two yield points in shear stress-strain curves at lower temperatures, while only one yield point at higher temperatures. The shear strength and modulus decrease with temperatures. The specimen undergoes four deformation stages: the elastic stage, the yield stage of Cu, the yield stage of Ta, and the plastic flow stage. Its yield depends on dislocation nucleation and expansion of Ta, but the plastic deformation in the flow stage is jointly determined by the defect evolution of Cu and Ta. At high temperatures, defects are more prone to nucleation, while dislocation activities are suppressed. Compared to Ta, the suppression of high temperatures on dislocation activities of Cu is more pronounced. Cu is more susceptible to generating shear bands than Ta and high temperatures can promote the nucleation and growth of shear bands.
10.1016-j.apsusc.2025.163691	14	strength; properties; conductivity; electrical; mechanical; cu-; grain; mpa; electrical conductivity; aging; precipitation; phase; mechanical properties; tensile; phases	Metallic glasses (MGs) demonstrate exceptional wear resistance attributed to their unique atomic structure. However, the micro-mechanism of the wear resistance enhancement in the friction process is still unclear. Therefore, the scratching of CuxZr100-x (x = 20, 30, 40, 50, 60, 64.5, 80 at%) MGs were simulated by molecular dynamics in this paper. As the Cu element increases, the force applied by the cutting tool increases, while the average friction coefficient decreases. The topologically close-packed (TCP) clusters increase with rising Cu element, undergoing a localized dynamic process of destruction-reorganization cycle. Under the action of cutting tools, TCP clusters were damaged, with typical icosahedral structures exhibiting the highest number and suffering the most severe damage. The high content of icosahedron results in lower volume and higher density of the workpiece. This led to tighter local atomic packing and consequently enhanced tool-workpiece interactions, manifesting as increased friction and normal forces. These intensified mechanical responses facilitate hardness elevation through densification effects, thereby improving wear resistance. This paper systematically investigates microstructural evolution and wear resistance enhancement mechanism of MGs during scratching.
10.1016-j.apsusc.2025.164261	-1		An in situ-generated Cu-CoCrFeNiTi high entropy alloy (HEA) (referred to simply as Cu-HEA) composite coating was fabricated on a Cu substrate via laser cladding to enhance high-temperature performance. The microstructure of the composite coating was characterized, and its wear performance at 400 degrees C and 600 degrees C was evaluated. Then, the formation of the Cu-HEA composite coating and its wear mechanism at different temperature was explored. The results revealed micron-sized Cu-rich regions and γ′ particles within the FCCstructured HEA coating, along with a semi-coherent interface between Cu and HEA. The Cu-HEA composite coating exhibited an average microhardness of 577 HV0.1 with wide fluctuations. The wear track area of the composite coating is 2.8 times that of the Cu substrate at 400 degrees C, and the wear resistance was further improved with the temperature increasing to 600 degrees C. Post-wear analysis indicated that the generation of Ti oxide film suppressed the crack propagation. The deformation ability of Cu-rich regions reduced the delamination, enhancing wear resistance and these impacts were further enlarged with the increasing temperature. The in situgenerated Cu-HEA composite coating significantly improved the wear resistance life of copper components to adapt to practical applications under high temperature conditions.
10.1016-j.apsusc.2025.164513	-1		Cu-21 at% Ta thin films were deposited on polyimide (PI) substrate by co-sputtering technique. The surface of asdeposited Cu-Ta alloy was smooth, however, a large number of Cu NPs were spontaneously formed on the films' surface after annealing at 260 degrees C, with an average Cu NPs size of 85.3 nm. Then, the average particle size of Cu NPs increases to 91 nm after being covered with a 6 nm Ag layer. Antibacterial activity tests in vitro showed that both the Cu NPs/Cu-Ta films and Ag layer/Cu NPs/Cu-Ta films exhibited excellent antibacterial properties at high concentrations of bacteria and a short time of co-culture, with antibacterial rates of over 99.95 %. The excellent antibacterial properties of Cu NPs/Cu-Ta film are mainly attributed to the release of Cu ions and the ROS mechanism, as well as the destruction of the bacterial flagellum by Cu NPs. Cu NPs/Cu-21 at% Ta films have great potential for application in antibacterial materials.
10.1016-j.apt.2014.12.005	-1		The phase stability of Cu-16 at. % Al and Cu-30 at. % Al alloys obtained by a planetary and an horizontal mills was investigated. The analysis was carried out using X-ray diffraction and various transmission electron microscopy (TEM) techniques. X-ray diffraction analysis gives a statistical overview of the main equilibrium phases present. Meanwhile, the different TEM techniques allow the detection of either the minor phases or the ones having crystalline domains smaller than 5 nm. The solid solution equilibrium a phase was obtained using both milling processes on the Cu-16 at. % Al. Instead, the final intermetallics observed for Cu-30 at. % Al were not the equilibrium ones according to the phase diagram. The planetary mill produced a mixture of a and gamma(2) phases and less than a 2 at. % of beta phase. The horizontal mill produced a gamma(2) phase and less than a 2 at. % of alpha(2) and gamma phases. For both compositions, the horizontal mill seems to be more efficient to achieved the equilibrium intermetallic compound.
10.1016-j.apt.2015.05.003	-1		In this paper, Cu-Y composite materials containing different content of Y were prepared with optimized hot-press and cold-press forming process based on L9 (34) orthogonal experiment and their physicochemical and mechanical properties including relative density, conductivity, oxidation resistance and hardness were been tested. The results indicate that the optimum preparation condition was: sintering temperature 800 degrees C, sintering time 3 h, pressure 30 MPa, Y-doping concentration 0.5 wt% for hot-press forming and sintering temperature 880 degrees C, sintering time 3 h, pressure 600 MPa, Y-doping concentration 0.5 wt% for cold-press forming. The addition of yttrium can improve the hardness and oxidation resistance of copper significantly and has the opposite effect on conductivity. The overall performances and process conditions of samples prepared by hot-press forming were significantly superior to those of cold-press forming.
10.1016-j.apt.2015.11.005	16	wear; composite; composites; powders; milling; particles; powder; wt; sliding; friction; hardness; matrix; mechanical; surface; properties	In this study porous copper nanocomposite reinforced with Al2O3 nanoparticles was successfully produced with adjustable mechanical properties and homogeneous pore morphology using powder metallurgy process. For this purpose, lost carbonate sintering (LCS) method with K2CO3 as a filler material was used to fabricate composite foam. The process consisted of mixing of metal powder and adjustable nano particles along with filler material, pressing and sintering. Under this condition the filler material was disappeared during sintering and a homogenous porous structure was formed. Experiments were conducted with 2 wt% of nano alumina and different weight fractions (15, 20, 30, 40, and 50) of K2CO3. Type and morphology of pores were investigated using scanning electron microscopy (SEM). Differential thermal analysis (DTA) and thermo gravimetric analysis (TGA) were also carried out to determine thermal behavior of potassium carbonate. EDS and XRD methods were used to analyze phase transformation during manufacturing process. Mechanical properties of the produced samples were investigated by uniaxial compression test. Compressive behavior of nanocomposite copper foams showed that they present more enhanced mechanical behavior in comparison with regular copper foams. The results showed that plateau stress of nanocomposite foam increased more than 2 times in compared with regular copper foam in same porosity percentage. The examination of uniaxial compression tests showed that the plateau stress and energy absorption of nanocomposite foams were in the range of 18-111 MPa and 6.82-29.97 MJ/m(3), respectively.
10.1016-j.apt.2017.04.023	16	wear; composite; composites; powders; milling; particles; powder; wt; sliding; friction; hardness; matrix; mechanical; surface; properties	The Cu-Fe and Cu-Fe-SiC nanocomposite powders were synthesized by a two step mechanical alloying process. A supersaturated solid-solution of Cu-20 wt% Fe was prepared by ball milling of elemental powders up to 5 and 20 h and subsequently the SiC powder was added during additional 5 h milling. The dissolution of Fe into Cu matrix and the morphology of powder particles were analyzed by X-ray diffraction (XRD) and scanning electron microscopy (SEM), respectively. It was found that the iron peaks in the XRD patterns vanish at the early stages of mechanical alloying process but the dissolution of Fe needs more milling time. Moreover, the crystallite size of the matrix decreases with increasing milling time and the crystallite size reaches a plateau with continued milling. In this regard, the addition of SiC was found to be beneficial in postponing the saturation in crystallite size refinement. Moreover, the effect of SiC on the particle size was found to be significant only if it is added at the right time. It was also found that the silicon carbide and iron particles are present after consolidation and are on the order of nanometer sizes.
10.1016-j.apt.2017.05.005	16	wear; composite; composites; powders; milling; particles; powder; wt; sliding; friction; hardness; matrix; mechanical; surface; properties	Preparation of metal matrix composites with homogenously distributed reinforcement is a difficult process. The process can be even more complex when the reinforcement particles are nano-particles. In this paper, three different techniques (dry mixing, mechanical alloying and mechanochemical) were applied to produce Cu-Al2O3 nano composite with three different Al2O3 content (2.5, 7.5 and 12.5.wt%). XRD, SEM and EDX analysis were conducted to analyse the physical and structural properties of the produced samples. Rockwell hardness test and compression test were applied to determine the mechanical properties of the produced composites. A 2D axisymmetric FE model was implemented using commercial software to predict the Rockwell hardness of the prepared samples. The results show that dry mixing and mechanical alloying techniques are valid for production of metal matrix composites with large reinforcement particle size and low reinforcement content. However, mechanochemical technique can be used to produce Cu-Al2O3 nano composite with high reinforcement weight fractions. Homogenously distributed dispersed nano alumina copper matrix can be achieved by applying mechanochemical technique and as a result, the mechanical and physical properties can be improved. The hardness predicted by the presented FE model correlates well with the experimental observation.
10.1016-j.apt.2017.07.012	4	transformation; martensite; martensitic; phase; shape; beta; memory; shape memory; temperature; temperatures; martensitic transformation; gamma; transformation temperatures; effect; thermal	In this work, the thermal stability of two samples of Cu-11.8 wt%Al obtained by different milling processes is analyzed. Several TEM techniques were used and HT-XRD experiments performed to determine the crystal structure and the morphological microstructure of the samples obtained during different heat treatments. The heat treatments were: quenching from 850 degrees C to room temperature and two consecutive calorimetric runs at 5 degrees C/min. After the quenching, alpha 2 is the major phase observed, reaching 95 mass%. The remaining 5 mass% consisted of martensitic phases: one sample ha gamma', a hexagonal structure, and the other beta(1)', a rhombohedral structure. During the first calorimetric run, the sample containing the gamma' phase exhibited a calorimetric event and the sample containing the beta(1)' phase did not. The calorimetric event is attributed to the austenitic transformation gamma' -> beta(1). The lack of calorimetric event in the sample containing the beta(1)' is associated with the inhibition of the transformation beta(1)' -> beta(1) because of the precipitation of the gamma(2) phase. Finally, the absence of a calorimetric event in the second run with the first sample is associated with the retransformation to beta(1)' instead to gamma' phase during cooling of the first calorimetric run. These studies determined that the first sample is a better candidate than the second sample to produce a shape memory alloy after thermo-mechanical treatments of the milled powders.
10.1016-j.apt.2017.11.027	-1		Comparative studies of the influence of carbon allotropic form on the formation of the structural-phase composition of copper-based composites have been performed by means of Scanning Electron Microscopy, X-ray and Thermal analysis and Raman spectroscopy. It has been stated that the kinetics of solid state reactions in the systems Cu-C-60/70 and Cu-C-g obtained in process of mechanosynthesis depend on deformational stability and oxidation-reduction properties of fullerite and graphite. It has been shown that partial destruction of fullerene molecules in the Cu-C-60/70 sample results in the formation of an amorphous fullerite-like phase, copper oxide Cu2O, and supersaturated solid solution Cu(C, O). Total destruction of fullerene molecules in the system Cu-C-60/70 results in the formation of supersaturated solid solution Cu(C), just like in the case of the composite Cu-C-g.
10.1016-j.apt.2018.05.001	-1		At present, one of crucial limitations for the hot isostatically pressed (HIPed) Cu-3Ag-0.5Zr alloy, which is used on the combustion chamber liner of aerospace engine, is the high oxygen content, which easily results in the intergranular fracture under high temperature, pressure, liquid hydrogen and oxygen environment during operation. In this study, a novel effective oxygen control method is developed, for which vacuum degassing process is integrated with a flowing hydrogen reduction reaction at an elevated temperature before HIP. For this technique, a container is designed with two gas pipes for hydrogen inflow and outflow, so the hydrogen circulation can be established. Allowing hydrogen to react effectively with oxygen, the oxygen content of HIPed alloy is found to drop significantly from 140 ppm (raw powder) to 28 ppm, which is equivalent to the oxygen-free copper and copper alloys. As a result of the reduction, no prior particle boundaries could be observed in the low oxygen content material. Although the tensile strength of the materials with and without employing this technique does not vary significantly, the ductility of low oxygen content material has improved by about 70% at 500 degrees C. This significant improvement of ductility is critical to ensure the safety critical PM components. Crown Copyright
10.1016-j.apt.2018.09.018	-1		The heterogeneity of grain refinement and texture formation in conductive copper powder during pulsed electric current sintering have been investigated by means of microstructural analysis of the particle-contacting zone of the samples sintered with micron-sized powders. The particle-contacting region was indicated to experience a higher level of grain refinement than the particle center due to the inhomogeneous temperature distribution among the particle when pulsed electric current passed through . Meanwhile, two main textures of Cube (1 0 0)[0 0 1] texture and Goss (1 1 0)[0 0 1] texture were directly detected in the sintered Cu samples by a combination of electron backscatter diffraction and X-ray diffraction. Based on the experimental results, a feasible mechanism for the formation of texture during the pulsed electric current sintering has been proposed by considering the applied uniaxial pressure and pulsed electric current as well as the rearrangement of grains. In addition, the effects of heterogeneous grain refinement and texture formation on the tensile properties of the sintered Cu samples were also discussed based on the tensile properties and fractographic. These results would contribute to the basic understanding of the sintering mechanisms in pulsed electric current sintering process.
10.1016-j.apt.2019.07.013	15	aging; strength; conductivity; electrical conductivity; electrical; mpa; treatment; strengthening; degrees; cu-; cold; precipitation; tensile strength; tensile; iacs	The Cu-2Cr-1Nb (at%) alloy powder was prepared by close-coupled argon gas atomization. The morphology, microstructure and phase were characterized by SEM, TEM, HRTEM, SAED and XRD. The effects of heat treatment on the microstructure and microhardness of the powder were investigated. The alloy matrix had equiaxed crystal structure, and the second phase was Cr2Nb intermetallic compound in sub-micron and nano-scale. Compared with large powder, the second phase of small powder is finer, and its distribution in the matrix is more uniform, the microhardness of the small powder is higher. After heat treatment at 773 K for 1 h, Cr and Nb precipitated and formed a large number of small precipitates, age hardening and peak aging phenomena occurred, and the peak hardness of the powder reached 130 HV. With the increase of heat treatment temperature, the second phase was coarsened. When the heat treatment temperature was 973 K, the short-time heat treatment hardening and long-time heat treatment softening were shown. However, after the heat treatment at 1223 K, only softening phenomenon was observed. This method can be used to prepare the excellent powder for Cu-Cr-Nb alloy, which can be used as a potential structural material for aerospace.
10.1016-j.apt.2019.09.013	-1		The study evaluates the effect of introducing Cu granules and control milling on the microstructure, interfacial bonding and mechanical properties including sintered density, hardness, compressive strength, flexural strength and electrical conductivity of Copper-Graphite (Gr) composite synthesize by flake powder metallurgy (Flake PM). It develops the flake composite particles by control mechanical alloying (MA) which further laminates over the refine granules surface. This encapsulation facilitates the strong interfacial bonding among the composite constituents during sintering. Results highlight that the 10% Cu granules in Cu-10Gr composite exhibit excellent mechanical properties. It increases the relative density, hardness, compressive strength, and flexural strength by 4.19%, 28.23%, 98.31%, and 11.8% respectively. However, the electrical conductivity increases by 6.73% (%IACS) for 15% of Cu granules in the Cu-10Gr composite. The improvements in the results are the synergistic coordination of dispersion homogeneity, surface integrity, work hardening, and the superior interfacial adhesion between composite powder and Cu granules.
10.1016-j.apt.2021.01.015	17	wear; composites; coating; friction; composite; coatings; surface; tribological; properties; wear resistance; resistance; powder; sliding; matrix; wear rate	Using Sn and Cu-Al powders as raw materials, three oxide dispersion-strengthened (ODS) Cu-10Sn alloy powders with different Al2O3 mass content (0.42%, 0.85% and 1.68%, respectively) were prepared by mechanochemical synthesis combined with diffusion alloying method. The oil bearings were then fabricated by pressing and sintering. The effects of Al2O3 on microstructures and properties of the powders and the oil bearings were investigated. The results show that Al2O3 nanoparticles with sizes of about 5 nm are uniformly distributed in the ODS Cu powders. The content of Al2O3 nanoparticles has no effect on the distribution uniformity of tin during the diffusion process. And three ODS Cu-10Sn alloy powders with homogeneous tin distribution are prepared. However, the temperatures of forming liquid phases in the ODS Cu-10Sn alloys decrease with increasing Al2O3 content. This affects the sintering behaviors and mechanical properties of oil bearings. Increasing Al2O3 content also has a significant promoting effect on the precipitation of Sn-rich particles. In order to synergize the solid solution strengthening of tin and the dispersion strengthening of Al2O3 nanoparticles, the content of Al2O3 in the ODS Cu-10Sn alloys will not exceed 0.85%. The ODS Cu-10Sn oil bearings with 0.42% Al2O3 sintered at 900 degrees C have the best comprehensive properties, with uniform radial and axial shrinkage, oil content of 19.1%, radial crushing strength of 284 MPa and micro-hardness of 142 HV.
10.1016-j.apt.2021.05.052	-1		High-purity Cu powders (99.967%) can be obtained by the electrorefining of Cu-Ni alloy (Ni <= 5%) in choline chloride-ethylene glycol deep eutectic solvent (ChCl-EG DES) at near room temperature. The electrochemical separation behaviors of Cu and Ni have been investigated by linear sweep voltammetry in 0.1 M CuCl + ChCl-EG DES. The results show that the oxidation potential of Cu is more positive than that of Ni, which implies Cu and Ni can be separated by electrochemistry. And the increasing of temperature is beneficial to the decontamination of Ni from Cu-Ni alloy. Besides, the effects of current density (2-10 mA.cm (2)) and reaction temperature (323-363 K) on the current efficiency and specific energy consumption during the electrorefining process are also analyzed, respectively. The highest current efficiency (99.89%) and the corresponding specific energy consumption (281.492 kW.h .t(1)) can be achieved at 10 mA.cm (2) and 363 K. The morphologies of Cu powders change from cauliflower-like to wheat ear-like with the increasing of current density. This finding provides a theoretical guidance for the separation of Ni from Cu-Ni alloy by an eco-friendly and facile electrorefining in ChCl-EG DES.
10.1016-j.apt.2021.07.012	16	wear; composite; composites; powders; milling; particles; powder; wt; sliding; friction; hardness; matrix; mechanical; surface; properties	The present work elucidates the effect of powder processing conditions (milling/mixing) and conductive alloying element (Al: aluminium) and ceramic (ZrB2: zirconium diboride) reinforcement addition on the densification, microstructure and electrical conductivity of copper (Cu) processed via hot pressing route. Disregard of alloying element/reinforcement/content or powders preparation method, the density of Cu materials varied between 92.16 and 99.76% pth (theoretical density) after hot pressing at a low temperature of 500 degrees C. In case of Cu-Al alloys, the powder processing method significantly influenced its microstructure and conductivity. Particularly the Cu-Al alloys processed using mixed powders consisted of various phases Cu, a-Cu, 71 (Cu9Al4), 8 (Cu3Al2), zeta 1 (Cu4Al3), eta 2 (CuAl) and 0 (CuAl2) and the Cu alloys prepared using milled powders composed of either only a-Cu or a-Cu and 71 (Cu9Al4) phases (depending on the Al content). Whereas, only Cu and ZrB2 phases were observed with the Cu-ZrB2 composites processed using either milled or mixed powers. In case of Cu-Al alloys, the hardness (0.88-3.41 GPa) and strength (540.30-1120.18 MPa) of Cu increased with the addition of Al. Interestingly, the hardness (0.88-2.55 GPa) and strength (508.50-970.60 MPa) of Cu increased upto 5 wt% ZrB2 and then they lowered with further addition of ZrB2. In particular, the hardness and strength of Cu-ZrB2 composites are lower than Cu-Al alloys reflecting the effectiveness of solid solution strengthening in the Cu alloys as compared to dispersion strengthening mechanism in Cu composite. The pure Cu prepared using milled powders exhibited low conductivity (75.70% IACS) than Cu processed using as-received/un-milled powders (97.00% IACS). Also, the Cu-ZrB2 composites measured with better electrical conductivity than Cu-Al alloys. Depending on the milling conditions and alloying/reinforcement amount, the conductivity of Cu-ZrB2 composites varied between 44.10 and 88.70% IACS.
10.1016-j.apt.2021.11.012	-1		Composites of Cu-5wt%Graphite were prepared by high-energy milling, under argon atmosphere for milling time of up to 50 h, to investigate the influence of the milling time on the size and dispersion of the copper and carbon phases. The formation of a monophasic carbon-copper solid solution was also investigated. The powder samples were collected at different times and characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM and FESEM), transmission electron microscopy (TEM), energy dispersive X-ray spectroscopy (EDS) and Raman spectroscopy. Composite particles were formed by fragments of graphite embedded in the soft Cu matrix. After 50 h of milling, the Cu phase had a crystallite size of 24 nm and micro-strain of 0.26 %. The lattice parameter showed a reduction of 0.001545 nm and reached a value of 0.360152 nm. Furthermore, no carbon diffraction peak was observed in the milled powders, due to the small graphite crystallites. Meanwhile, the Raman spectra showed that the carbon phase remains crystalline, even after 50 h of milling. When the composite was annealed at 600 degrees C, for 1 h and under argon atmosphere, no carbon precipitate was observed. These results suggest the absence of the formation of a solid solution of carbon in copper.
10.1016-j.apt.2022.103523	17	wear; composites; coating; friction; composite; coatings; surface; tribological; properties; wear resistance; resistance; powder; sliding; matrix; wear rate	In this study, high-performance fine-grained W-Cu sintered blocks with the addition of dispersed Al2O3 particles were successfully produced by low temperature liquid-phase sintering, using the raw material of ultrafine W-Cu alloy powder. The ultrafine W-Cu alloy powder was obtained by a two-step reduction process composed of stages of carbothermal reaction and hydrogen deep deoxidation. The fine Al2O3 grains with uniform distribution in W-Cu alloy were introduced by spray method, leading to the decrease of W grain size and W-W connectivity. The relative densities of all sintered blocks were>97%, and a higher degree of densification ensures that the alloy has excellent comprehensive properties. With the increase of Al2O3 content, W grain size and W-W connectivity of sintered W-Cu samples decrease from 664 nm to 472 nm and 0.2 to 0.14, respectively. The W-Cu alloy with the ultimate tensile strength of 415 MPa and the highest elongation of 7.22% was obtained when the addition amount of Al2O3 was 0.5 wt%. At the same time, it also possessed the maximum bending strength of 1028 MPa and microhardness of 312 HV, respectively. In addition, due to the good network structure of Cu and uniform three-phase distribution, the sintered samples had excellent conductivity and compressive strength .
10.1016-j.apt.2022.103545	-1		Lead-free FeS/Cu-Bi (FCB) self-lubricating composites were prepared via shift-speed ball milling (SSBM) and powder metallurgy. The microstructure and evolution of mixed powders were studied, and the mechanical and tribological properties of the FCB composites were tested. SSBM includes long-term low-speed ball milling (LSBM) and short-term high-speed ball milling (HSBM). In the early LSBM, the matrix phase CuSn10 powder was flattened into flakes, and the lubricating phases FeS and Bi were refined and gradually dispersed on the CuSn10 flakes. After short-term HSBM, FeS and Bi were further trapped on the CuSn10 flakes, which not only improved the bonding performance between the lubricating phase and copper alloy but also protected the continuity of the copper alloy matrix from additional damage. 6 + 1 h SSBM (6 h LSBM + 1 h HSBM) improved the mechanical properties, antifriction and wear resistance of FCB composites. Compared with traditional HSBM, SSBM provides a new way to prepare FCB self-lubricating composites with better comprehensive properties.
10.1016-j.apt.2024.104554	-1		Cu-Ag flake powders demonstrate strong potential applying as the conductive phase in conductive polymer composite due to the good combination properties of electrical conductivity and anti-oxidation performance. In this study, the influence of solvothermal treatment in sodium formate on the surface microstructure and anti-oxidation performance of flake Cu-Ag powder was investigated systematically. The results indicated that solvothermal treatment at 200degree celsius for at least 16 h significantly enhanced the oxidation resistance of the aged Cu-5Ag flake powder in air, which was ascribed to the reaction between Cu matrix and sodium formate solution to create a [Cu(l.HCOO)(OH)2]2 layer on the surface of powders and precipitated Ag along GBs during aging treatment. During the oxidation process, the [Cu(l.HCOO) (OH)2]2 formed on the surface of flake powders provided cathodic protection to Cu atoms, and the precipitated Ag along GBs blocked the diffusion channels of Cu and O atoms, which resulted in exceptionally high anti-oxidation performance up to 283degree celsius of Cu-Ag flake powders. (c) 2024 The Society of Powder Technology Japan. Published by Elsevier BV and The Society of Powder Technology Japan. All rights are reserved, including those for text and data mining, AI training, and similar technologies.
10.1016-j.apt.2024.104653	-1		Cu/TiB2 composite combines electrical conductivity and wear resistance, leading to its wide application prospect in electrical contact. In this study, electromagnetic impact was applied to compact Cu/TiB2 powder. The interaction between powder and die under electromagnetic impact was analyzed by observing the surface quality, density, microstructure, and hardness. The results showed that when the energy was less than 21 kJ, the increase in energy could enhance density and tensile strength of the compact. However, when the energy exceeded 21 kJ, the state of compact hardly changed and burr near the edge would be worsened. Besides, the hardness of the upper surface increased gradually from the center to the edge, while the opposite was true for the lower surface, reflecting the spatial distribution of density. With the aid of simulation, it was found that the stress wave propagation influenced the densification behavior and led to the variation of density. (c) 2024 Published by Elsevier B.V. on behalf of The Society of Powder Technology Japan. All rights are reserved, including those for text and data mining, AI training, and similar technologies.
10.1016-j.arabjc.2013.07.060	2	corrosion; surface; film; electrochemical; films; spectroscopy; layer; current; solution; potential; resistance; composition; x-ray; ions; showed	The inhibition performance of 5-(3-aminophenyl) tetrazole (APT) in controlling corrosion of Cu-Ni (90/10) alloy in synthetic seawater and synthetic seawater containing 10 ppm sulphide has been investigated. Electrochemical impedance, potentiodynamic polarization, cyclic voltammetry (CV) weight-loss and scanning electron microscopy (SEM)/energy dispersive X-ray analysis (EDX) studies were employed to evaluate the inhibitor performance. The results of impedance studies show that both charge transfer resistance and film resistance increase with an increase in APT concentration and at a concentration of 6.5 mM, APT functions as an excellent inhibitor with an inhibition efficiency of 99.72%. The phase angle Bode plots are more broadened and showed a phase maximum of 81 degrees in the presence of APT. The APT film is highly protective even at a temperature of 60 degrees C. Potentiodynamic polarization studies inferred that APT functions as a mixed inhibitor. CV studies revealed that the protective APT film is stable even up to anodic potentials of + 850 mV vs. Ag/AgCl. Weight-loss studies showed an inhibition efficiency of more than 99% in the presence of APT even after 30 days immersion period. SEM-EDX studies confirm the absence of any corrosion and presence of protective APT film on the alloy surface. (c) 2013 Production and hosting by Elsevier B.V.
10.1016-j.asej.2025.103746	14	strength; properties; conductivity; electrical; mechanical; cu-; grain; mpa; electrical conductivity; aging; precipitation; phase; mechanical properties; tensile; phases	This study investigates the influence of Pb-rich secondary phase (PSP) morphology on the tribological behavior of Cu-Pb alloys by combining experimental characterization with molecular dynamics (MD) simulations. Reticular-structured (R-Alloy) and globular-distributed (G-Alloy) PSPs were fabricated based on precise composition control and characterized using high-resolution microscopy. Under continuous friction conditions, MD simulations reveal that PSP morphology critically governs lubricating film formation through distinct Pb migration mechanisms: the interconnected network in R-Alloy restricts Pb diffusion, resulting in discontinuous films, whereas G-Alloy enables directional Pb migration and the formation of uniform lubricating layers. Quantitative analysis links strain-field gradients and thermal evolution to friction stability, showing that globular PSPs promote homogeneous deformation and better heat dissipation. The strong agreement between experimental and simulation results validates the approach and demonstrates that tailoring PSP architecture-particularly toward a globular configuration-is an effective strategy for optimizing the tribological performance of self-lubricating alloys.
10.1016-j.bioelechem.2013.12.005	2	corrosion; surface; film; electrochemical; films; spectroscopy; layer; current; solution; potential; resistance; composition; x-ray; ions; showed	The present paper reports the on-line monitoring of corrosion behavior of the CuNi 70:30 and Al brass alloys exposed to seawater and complementary offline microbiological analyses. An electrochemical equipment with sensors specifically set for industrial application and suitable to estimate the corrosion (by linear polarization resistance technique), the biofilm growth (by the BIOX electrochemical probe), the chlorination treatment and other physical-chemical parameters of the water has been used for the on-line monitoring. In order to identify and better characterize the bacteria community present on copper alloys, tube samples were collected after a long period (1 year) and short period (2 days) of exposition to treated natural seawater (TNSW) and natural seawater (NSW). From the collected samples, molecular techniques such as DNA extraction, polymerase chain reaction (PCR), denaturing gradient gel electrophoresis (DGGE) and identification by sequencing were performed to better characterize and identify the microbial biodiversity present in the samples. The monitoring data confirmed the significant role played by biofouling deposition against the passivity of these Cu alloys in seawater and the positive influence of antifouling treatments based on low level dosages. Molecular analysis indicated biodiversity with the presence of Marinobacter, Alteromonas and Pseudomonas species.
10.1016-j.bioelechem.2022.108052	2	corrosion; surface; film; electrochemical; films; spectroscopy; layer; current; solution; potential; resistance; composition; x-ray; ions; showed	In this work, we studied the microbiologically influenced corrosion mechanism of Cu by marine ammonifying bacterium Alcaligenes aquatilis. Through immersion experiments, we found that A. aquatilis could accelerate the corrosion rate of copper, resulting in the development of pits. In the presence of A. aquatilis, the morphology and composition of the corrosion products differed from the abiotic samples, and we found that Cu2O was the main corrosion product. By analyzing the biotic medium and experimental NH3 addition, we verified that NH3 was the main component that intensified copper corrosion. Furthermore, we found that NH3 played a catalytic role in the corrosion of Cu in the presence of A. aquatilis.
10.1016-j.bioelechem.2023.108633	2	corrosion; surface; film; electrochemical; films; spectroscopy; layer; current; solution; potential; resistance; composition; x-ray; ions; showed	In this study, a novel Cu-based (Cu55Al20Ni12Ti8Si5, at%) medium-entropy alloy (MEA) coating was prepared by high-velocity oxygen-fuel (HVOF) spraying technology. Thermo-Calc was employed to simulate the phase diagram of the alloy system. Phase composition and microstructure of the as-sprayed coating were characterized by means of XRD, FESEM, TEM and STEM/EDX. The effect of sulfate-reducing bacteria (SRB) on the corrosion behavior of the coating and the as-cast Ni-Al bronze (NAB) was investigated using electrochemical measurements and surface characterization. The Thermo-Cala simulation results showed that the alloy system presented a single BCC solid solution phase, while the detailed characterization of microstructure indicated that a few NiTi-rich B2ordered precipitates could be also found in the as-sprayed coating other than the Cu-rich BCC matrix. Electrochemical studies illustrated that the coating exhibited superior corrosion resistance than the NAB in SRB medium, the corrosion acceleration efficiency induced by SRB of the NAB (95.3 %) was more severe than that of the coating (63.8 %). Surface analysis results demonstrated the occurrence of pitting corrosion and the formation of Cu2S on the coating surface after corroded in SRB medium. Corrosive metabolite HS- induced microbiologically influenced corrosion was considered as the main corrosion acceleration mechanism caused by SRB.
10.1016-j.bioelechem.2024.108854	2	corrosion; surface; film; electrochemical; films; spectroscopy; layer; current; solution; potential; resistance; composition; x-ray; ions; showed	This research examined the varying susceptibility of pure copper (Cu), 90/10 copper-nickel (Cu-Ni) alloy, 70/30 Cu-Ni alloy, and pure nickel (Ni) to microbiologically influenced corrosion (MIC) induced by Desulfovibrio vulgaris, with a focus on the elemental composition of the materials. The results revealed a progressive shift in MIC behavior across these metals and alloys, with increased corrosion severity observed as Ni content decreased. Element Ni improved the corrosion resistance of the alloy while also preventing the growth of microorganisms. Both planktonic and sessile cell counts decreased as the Ni content increased. The corrosion rate, determined by weight loss, followed this order: pure Cu (25.7 +/- 3.8 mgcm(-2), 0.75 mmy(-1)) > 90/10 Cu-Ni alloy (9.1 +/- 1.4 mgcm(-2), 0.27 mmy(-1)) > 70/30 Cu-Ni alloy (4.3 +/- 0.8 mgcm(-2), 0.16 mmy(-1)) > pure Ni (2.1 +/- 0.7 mgcm(-2), 0.06 mmy(-1)). The corrosion current density (i(corr)) of pure Cu (3.03 x 10(-5) Acm(-2)) was approximately 20-fold that of pure Ni (1.54 x 10(-6) Acm(-2)). There was a correlation between the electrochemical and weight loss results. Thermodynamic analysis and experimental results indicated that M-MIC was the primary MIC mechanism for pure Cu. While both M-MIC and EET-MIC were engaged in the MIC mechanisms of 90/10 Cu-Ni and 70/30 Cu-Ni alloys, the predominant mechanism was EET-MIC for pure Ni.
10.1016-j.bioelechem.2024.108892	-1		This study investigates the corrosion of 90/10 copper-nickel (Cu-Ni) alloy caused by sulfate-reducing bacteria (SRB) in the presence of aluminum anodes, with particular emphasis on the role of electron supply in microbial corrosion and the resulting local corrosion failures. The study reveals that the electron supply from the anode supports SRB growth on the Cu-Ni alloy through an Electrons-siphoning mechanism. However, the supply is insufficient to sustain the SRB population, resulting in ineffective cathodic protection (icorr = 2.34 x 10-6 A cm- 2). The addition of 20 ppm riboflavin (RF) to the SRB biofilm enhances electrical activity and increases the electron donor density, thereby restoring the anode's protective effect. As a result, the icorr of the 90/10 Cu-Ni alloy decreases by an order of magnitude (to 3.5 x 10- 7A cm- 2). These findings provide valuable new insights into the mechanisms of microbial corrosion.
10.1016-j.calphad.2006.06.002	12	thermodynamic; ternary; phase; data; experimental; equilibria; phase equilibria; liquid; binary; experimental data; calculated; phases; literature; model; calphad	Based on all the available experimental phase equilibrium and thermochemical data, the Cu-Zr system has been thermodynamically reassessed by means of the CALPHAD (CALculation of PHAse Diagrams) technique. The substitutional solution model was used to describe the liquid and three terminal solid solutions, fcc-Al(Cu), bcc-A2(beta Zr) and hcp-A3(alpha Zr), and their excess Gibbs energies were formulated with the Redlich-Kister polynomial. Ten intermediate compounds, Cu9Zr2, Cu-51 Zr-14, Cu8Zr3, Cu2Zr, Cu24Zr13, Cu10Zr7, CuZr, Cu5Zr8, CuZr2-h and CuZr2-l, were contained in the system, and were treated as stoichiometric phases. For the phase CuZr2, there are the high and the low temperature modifications. The parameters of all the Gibbs energy expressions were optimized. A set of self-consistent thermodynamic parameters has been obtained. The calculated phase diagram and thermodynamic properties agree well with the available experimental data.
10.1016-j.calphad.2008.05.003	12	thermodynamic; ternary; phase; data; experimental; equilibria; phase equilibria; liquid; binary; experimental data; calculated; phases; literature; model; calphad	The thermodynamic description of the Cu-Si system has been updated with first-principles calculations of the epsilon-Cu15Si4 phase and solid solution phases. Calculated enthalpy of formation for the c-phase indicates that enthalpies of formation for intermetallic compounds in Cu-Si must be negative, which were evaluated as positive in the previous thermodynamic modelings. Enthalpies of mixing for the solid solution phases, bcc, fcc, and hcp, are also calculated from first-principles study of Special Quasirandom Structures (SQS) and all the solution phases exhibit similar mixing behavior. It is concluded that first-principles calculations of solid phases including solution phases can supplement scarce experimental data and be readily used in thermodynamic modelings.
10.1016-j.calphad.2009.03.005	12	thermodynamic; ternary; phase; data; experimental; equilibria; phase equilibria; liquid; binary; experimental data; calculated; phases; literature; model; calphad	Thermodynamic evaluation of Cu-Cu3P system has been conducted by applying subregular solution model with Gibbs energy of CUR formation that was newly determined by means of triple Knudsen cell mass spectrometry. Both the calculated vapor pressure of phosphorus and phase diagram of Cu-P system are excellently consistent with the literature data in the composition range of Cu-Cu3P, indicating that there is no significant thermodynamic inconsistency between the present work based on the Gibbs energy of Cu3P formation determined and the literature data.
10.1016-j.calphad.2009.07.003	12	thermodynamic; ternary; phase; data; experimental; equilibria; phase equilibria; liquid; binary; experimental data; calculated; phases; literature; model; calphad	The phase equilibria of the ternary Cu-Mn-Ni system in the region above 40 at% Mn at 600 degrees C were investigated by means of optical microscopy, X-ray diffraction, scanning electron microscopy with energy dispersive X-ray spectroscopy and electron probe microanalysis. The isothermal section of the Cu-Mn-Ni system at 600 degrees C consists of 4 two-phase regions (cbcc_A12+fcc_A1, cub_A13+fcc_A1, cbcc_A12+cub_A13, L1(0)+fcc_A1) and 1 three-phase region (cbcc_A12+cub_A13+fcc_A1). The disordered fcc_A1 phase exhibits a large continuous solution between gamma(Cu,Ni) and gamma(Mn). The L1(0) phase only equilibrates with fcc_A1 phase, and the solubility of Cu in L1(0) phase is up to 16 at%. A thermodynamic modeling for this system was performed by considering reliable literature data and incorporating the current experimental results. A self-consistent set of thermodynamic parameters was obtained, and the calculated results show a general agreement with the experimental data.
10.1016-j.calphad.2009.09.002	12	thermodynamic; ternary; phase; data; experimental; equilibria; phase equilibria; liquid; binary; experimental data; calculated; phases; literature; model; calphad	Based on the available thermodynamic information and diffusion coefficient data of the Cu-Sn binary system, the atomic mobilities of Cu and Sn in face-centered cubic (fcc) Cu-Sn alloys have been assessed as a function of temperature and composition in terms of the CALPHAD method using the DICTRA(R) software package. Optimized mobility parameters are presented. To testify the reliability of the optimized mobility parameters, the composition-distance profiles of the Cu/Cu-7 at% Sn diffusion couples at different temperatures (923 K, 1023 K and 1053 K) have been measured in the present work by means of electronic probe micro-analysis (EPMA). Comparisons between the calculated and measured diffusion coefficients show that most of the experimental information can be reproduced reasonably. The obtained mobility parameters can also predict satisfactorily composition-distance profiles of the diffusion zone in binary Cu-Sn diffusion couples determined in the present work and reported in published literature.
10.1016-j.calphad.2011.02.001	12	thermodynamic; ternary; phase; data; experimental; equilibria; phase equilibria; liquid; binary; experimental data; calculated; phases; literature; model; calphad	The isothermal section of the Cu-Si-Zn ternary system at 600 degrees C was experimentally determined with fifteen alloys by means of optical microscopy. X-ray diffraction, and the scanning electron microscopy with energy dispersive X-ray spectroscopy. At 600 degrees C, no ternary compounds were observed, and five three-phase equilibria were well determined. In particular, the longstanding controversy regarding the four three-phase equilibria in the Cu-rich corner involving the phases alpha, beta, gamma-Cu(5)Zn(8), and kappa-Cu(7)Si was resolved experimentally in the present work. In an effort to provide a compatible thermodynamic description of the Cu-Si-Zn system for the multi-component Al-based thermodynamic database, the Cu-Zn system was remodeled using the CALPHAD approach with a new sublattice model Zn(4)(Cu, Zn)(1) (Cu, Zn)(8) for the gamma-Cu(5)Zn(8) phase. Besides, the temperature dependence of enthalpy of mixing was also taken into account for the liquid phase. Subsequently, a thermodynamic description of the Cu-Si-Zn system was obtained over the entire composition range based on the presently modeled Cu-Zn system and the experimental data from the literature and the present measurements. It is found that most reliable experimental data in this ternary system are satisfactorily reproduced by the present thermodynamic modeling.
10.1016-j.calphad.2011.10.002	12	thermodynamic; ternary; phase; data; experimental; equilibria; phase equilibria; liquid; binary; experimental data; calculated; phases; literature; model; calphad	Using solid/solid diffusion couples and the electron probe microanalysis (EPMA) technique, the interdiffusion coefficients in fcc Cu-Al-Fe alloys at 1273 K were determined by means of Whittle and Green's method. Based on the atomic mobilities of three sub-binary systems available in the literature and the interdiffusivities determined, the atomic mobilities in fcc Cu-Al-Fe alloys were assessed by means of the DICTRA (Diffusion Controlled TRAnsformation) software package. The calculated interdiffusivities agree well with the experimental ones. Further verification of the atomic mobilities obtained was carried out through comprehensive comparisons between the model-predicted concentration profiles/diffusion paths of several diffusion couples and the experimental data. The results indicate that the atomic mobilities obtained can reproduce the experiment data reasonably well.
10.1016-j.calphad.2014.07.003	12	thermodynamic; ternary; phase; data; experimental; equilibria; phase equilibria; liquid; binary; experimental data; calculated; phases; literature; model; calphad	This study reports the thermodynamic assessment of the temperature and pressure dependence of molar volume of Cu and Zn, as well as their P-T phase diagrams based on the CALPHAD approach . The molar volume of fcc-Cu, hcp-Zn, and liquid phases as a function of both temperature and pressure was directly assessed from the data reported in the literature by implementing the CALPHAD-compatible equation of state (EOS). This EOS incorporates the quasi-harmonic model to eliminate the spurious predictions of negative heat capacity and thermal expansion at high pressure. Furthermore, the P-T phase diagram of each element was determined on the basis of the experimental results and calculated parameters. The experimentally estimated thermodynamic values are in good agreement with the calculated results.
10.1016-j.calphad.2016.08.001	12	thermodynamic; ternary; phase; data; experimental; equilibria; phase equilibria; liquid; binary; experimental data; calculated; phases; literature; model; calphad	The Ag-Zr and Cu-Zr binary systems are thermodynamically reassessed in this study. Not only phase diagrams, but also thermodynamic properties, such as enthalpy of formation for solids, activity for liquid, and enthalpy of mixing for liquid, are all calculated and compared with available experimental data to assure the accuracy of the assessment. Cu2Zr and Cu24Zr13 phases are considered as meta-stable phases, which would not exist in the Cu-Zr equilibrium phase diagram. The artifact of liquid miscibility gap at high temperature is avoided in the presently calculated phase diagrams.
10.1016-j.calphad.2017.01.004	12	thermodynamic; ternary; phase; data; experimental; equilibria; phase equilibria; liquid; binary; experimental data; calculated; phases; literature; model; calphad	All the thermodynamic and phase diagram information available in the literature on the Cu-Cr system, Cu-Fe-Cr system, and Cu-Fe-Mn system were critically evaluated and used in the thermodynamic optimization to obtain a set of consistent thermodynamic model parameters for the systems. The liquid solutions for the Cu-Cr, Cu-Mn, Fe-Cr, Cu-Fe-Cr, and Cu-Fe-Mn systems were described using the Modified Quasichemical Model (MQM) with pair approximation. The solid solution phases were modeled using the Bragg-Williams random mixing model. Accurate reproduction of all the reliable phase diagram and thermodynamic property data indicates the high reliability of the present thermodynamic optimizations.
10.1016-j.calphad.2017.01.009	-1		The equilibrium phase diagram of a Cu-Pd alloy has been computed using cluster expansion and Monte Carlo simulation methods combined with density functional theory. The computed phase boundaries show basic features that are consistent with the experimentally reported phase diagram. Without vibrational free energy contributions, the order-disorder transition temperature is underestimated by 100 K and the critical point is inconsistent with experimental result. The addition of vibrational free energy contributions yields a more qualitatively correct Cu-Pd phase diagram in the Cu rich region.
10.1016-j.calphad.2017.05.004	0	solidification; phase; magnetic; magnetic field; undercooling; field; liquid; separation; peritectic; immiscible; cu-; dendrite; phase separation; microstructure; primary	The designed liquid immiscibility of Cu-Ni-Fe-Mo-Si alloy led to separation of the spherical second liquid in the Cu-rich liquid, which solidified into coarse hard grains packed with Laves phase. The coarseness of hard grains was controlled not only by the repulsive interactions in Cu-Fe and Cu-Mo system, but also the refining effect of Ni and Si. CALPHAD analysis of the multicomponent system confirmed the correlation of the calculated fraction of the separated liquid with the observed grain dimensions. It also provided a powerful prediction of the precipitates constituting the hard grains. Almost all of the alloying effects on the observed microstructures were successfully interpreted based on equilibrium immiscibility calculations, although a reason for the refining of spheres with increasing Si remains unclear.
10.1016-j.calphad.2017.07.002	12	thermodynamic; ternary; phase; data; experimental; equilibria; phase equilibria; liquid; binary; experimental data; calculated; phases; literature; model; calphad	The Cu-Cr-Zr ternary system was investigated via thermodynamic modeling coupled with key experiments. The isothermal section of the Cu-Cr-Zr system at 1123 K was determined by means of optical microscopy, X-ray diffraction and electron probe microanalysis, and the phase transformation temperatures were measured by differential scanning calorimetry. The Cu-Cr sub-binary system was re-assessed with a substitutional solution model for the solution phases to ensure its compatibility in multi-component system. A set of self-consistent thermodynamic parameters for the Cu-Cr-Zr systems was obtained using the CALPHAD (CALculation of PHAse Diagram) approach, and the calculated phase diagram is in a satisfactory agreement with the present experimental results and literature information. An increase of the thermodynamic stability for the CuZr and Cr2Zr phases due to the ternary solubility is verified by calculation.
10.1016-j.calphad.2017.08.005	12	thermodynamic; ternary; phase; data; experimental; equilibria; phase equilibria; liquid; binary; experimental data; calculated; phases; literature; model; calphad	Utilizing five groups of bulk diffusion couples together with electron probe microanalysis technique, the composition-dependent ternary interdiffusion coefficients in fcc Cu-Ni-Sn alloys at 1023 K were determined via the Whittle and Green method. The presently obtained interdiffusion coefficients at 1023 K as well as our previously measured ones at 1073 K were combined with the slightly modified thermodynamic descriptions of the fcc Cu-Ni-Sn phase to explore atomic mobilities of Cu, Ni and Sn in fcc Cu-Ni-Sn alloys within the CALPHAD framework. In order to be consistent with the thermodynamic description, atomic mobilities in binary fcc Ni-Sn alloys were re-evaluated in the present work. The quality of the assessed kinetic characteristics was confirmed by the comprehensive comparisons between various model-predicted diffusion behaviors and the experimental ones, including concentration profiles and diffusion paths.
10.1016-j.calphad.2018.02.008	12	thermodynamic; ternary; phase; data; experimental; equilibria; phase equilibria; liquid; binary; experimental data; calculated; phases; literature; model; calphad	In this work, solid-to-solid diffusion couples were assembled and annealed to investigate diffusion behavior and mechanical properties of the Cu-Zr system in temperatures range from 1043 K to 1113 K. Six intermetallic compounds (IMCs) Cu9Zr2, Cu51Zr14, Cu8Zr3, Cu10Zr7, CuZr, and CuZr2 were observed in the diffusion zone. Composition-dependent interdiffusion coefficients of IMCs have been calculated based on the measured composition Cu profiles of the diffusion zones by using Sauer-Freise method. And the average effective interdiffusion coefficients for each phase were also calculated by using Wagner method. The activation energies of diffusion are evaluated according to the average effective interdiffusion coefficient. Finally, the load-displacement curves measured by nano-indentation are obtained to characterize mechanical properties of Cu9Zr2 and Cu51Zr14, which have similar hardness and elastic moduli.
10.1016-j.calphad.2018.03.006	12	thermodynamic; ternary; phase; data; experimental; equilibria; phase equilibria; liquid; binary; experimental data; calculated; phases; literature; model; calphad	Due to their high corrosion resistance and thermal stability, Cu-Ni-alloys have essential role in many materials engineering applications. Lead is an alloying element in these alloys although it may also be considered as an impurity in certain cases. In copper rich alloys, lead tends to diffuse into the grain boundaries and weaken the hot-working properties. In addition to alloys design, accurate knowledge of phase relations and solubilities in the ternary Cu-Ni-Pb system has important role in improving the copper and nickel smelting and refuting processes. In the present work, an isothermal equilibration technique was used to measure the mutual solubilities of liquid lead and solid CuNi foil in the temperature range 1280-1530 K. The samples were equilibrated and an Inductively Coupled Plasma Atomic Emission Spectrometer (ICP-AES) and an Electron Probe Micro Analyzer (EPMA) were used to quantify the chemical composition of the phases. Selected solubility data obtained in this work were combined with the literature data to obtain a thermodynamic description of the Cu-Ni-Pb ternary liquid and fcc solid solution phases by applying the CALPHAD method. The ternary assessment agrees well with the experimental observations in this work.
10.1016-j.calphad.2018.12.012	12	thermodynamic; ternary; phase; data; experimental; equilibria; phase equilibria; liquid; binary; experimental data; calculated; phases; literature; model; calphad	The Knudsen method was used for measurements of mass loss rate of dilute solutions of bismuth and iron in liquid copper, in the temperature range from 1378 to 1631 K. The produced experimental data were used in the optimization procedure aimed at determination of parameters of the thermodynamic model of the Cu-Fe-Bi system, linking the measured mass change rates with the thermodynamic properties of this system. The model applied in this procedure uses equations proposed by Felton and Bale. They are an extension of a standard dilute interaction parameter formalism to non-dilute solutions. The obtained results made it possible to determine the value of the first order ternary interaction parameter: epsilon(BiFe) = 19034/T-7.140.
10.1016-j.calphad.2019.02.006	12	thermodynamic; ternary; phase; data; experimental; equilibria; phase equilibria; liquid; binary; experimental data; calculated; phases; literature; model; calphad	The thermodynamic activity of lithium was measured by Knudsen Effusion Mass Spectrometry (KEMS) within the Cu-Li-Sn system in the liquid region. For this purpose, eleven samples were studied between 773 and 1078 K in the Sn-rich part of the Cu-Li-Sn phase diagram. Mixing enthalpies, entropies and Gibbs energies were derived directly from the measured thermodynamic activity. The measured thermodynamic activities of Li were fitted to the Redlich-Kister-Muggianu (RKM) sub-regular solution model, by taking ternary interactions into account, using a mathematical regression procedure. Thereby, the partial and integral excess thermodynamic properties, the activities of Li, Cu and Sn and the ternary interaction L-parameters, as a function of temperature, were obtained.
10.1016-j.calphad.2020.101991	12	thermodynamic; ternary; phase; data; experimental; equilibria; phase equilibria; liquid; binary; experimental data; calculated; phases; literature; model; calphad	Vapor-liquid equilibria (VLE) of the Cu-Sn system have been investigated in the temperature range from 1612 to 1650 K and at pressure of 5 Pa. The VLE data of Cu-Sn alloy was calculated by using Wilson equation and compared with experimental values under vacuum condition. The thermodynamic consistency of the experimental data was checked by Van Ness method. The azeotropic and non-azeotropic regions are plotted by correlating the Wilson equation, vapor pressure equation and the enthalpies of vaporization. The calculated results reveal that the Cu-Sn system is located in azeotropic region which the specific composition and temperature of azeotropic point are x(Cu) = 0:71 and T = 1649 K. The agreements between calculated and measured results are good. This work provides an effectively method for predicting whether binary system will form an azeotrope or not and the azeoropic position in vacuum distillation. It can also be used to test the quality of a vapor-liquid equilibrium model and to guide experiments.
10.1016-j.calphad.2020.102216	12	thermodynamic; ternary; phase; data; experimental; equilibria; phase equilibria; liquid; binary; experimental data; calculated; phases; literature; model; calphad	Decades of scientific work dedicated to the investigation of phase diagrams gave significant benefit to industry and science. After all those years of phase diagram investigation still there is missing information about phase diagram of some ternary systems. One of those systems is Cu-Ge-Pb. It is known importance of Cu-based alloys and Ge-based alloys in electro industry. Since such combination is not tested before this work will provide information about phase diagram of ternary Cu-Ge-Pb system. In this work ternary Cu-Ge-Pb system has been tested experimentally and analytically by using Calphad model. Two isothermal sections at 600 and 400 degrees C and three vertical sections are experimentally tested and results were compared with calculated corresponding phase diagrams. None of the ternary compound and large solubility of third element in binary compound is not confirmed. Liquidus projection, invariant reaction and scheme of invariant reaction are presented. Scheil and Lever simulation of solid phases for Cu80Ge10Pb10 alloy were calculated.
10.1016-j.calphad.2021.102324	12	thermodynamic; ternary; phase; data; experimental; equilibria; phase equilibria; liquid; binary; experimental data; calculated; phases; literature; model; calphad	The phase equilibria of the Cu-Cr-Si ternary system were investigated via thermodynamic modeling coupled with key experiments. Seventeen ternary alloys were prepared to determine the isothermal sections of the Cu-Cr-Si system at 700 and 800 degrees C by combining X-ray diffraction (XRD) and scanning electron microscopy with energy dispersive X-ray spectroscopy (SEM/EDS). No ternary compound was found. The solubilities of the third element in binary compounds in the Cu-Si and Cr-Si systems were measured. Based on the thermodynamic descriptions of three constitutive binary systems available in the literature as well as the experimental phase equilibria data obtained from the present work and literature, thermodynamic re-assessment of the Cu-Cr-Si system was carried out by the CALPHAD (CALculation of PHAse Diagrams) approach . The substitutional model and sublattice model were used to describe the solution phases and intermediate phases, respectively. A set of thermodynamic parameters of the Cu-Cr-Si system was obtained. The calculated isothermal sections and vertical section are in good agreement with most of the reliable experimental data. The liquidus projection and reaction scheme of the Cu-Cr-Si system over the whole composition were also presented.
10.1016-j.calphad.2021.102344	12	thermodynamic; ternary; phase; data; experimental; equilibria; phase equilibria; liquid; binary; experimental data; calculated; phases; literature; model; calphad	In this study, the phase equilibria of the Cu-Ni-Sn ternary system reported in the literature were critically reviewed and the discrepancies between the results from different sources were clarified. The thermodynamic parameters of the sub-binary Ni-Sn system were updated using the CALculation of PHAse Diagram (CALPHAD) approach yielding significant improvements in the description of Fcc phase boundary. Besides, the artificial miscibility gap in Ni-Sn liquid phase obtained in the previous assessment was successfully removed. Subsequently, a set of self-consistent thermodynamic parameters for the Cu-Ni-Sn ternary system over the whole composition range was systematically optimized by considering the reviewed experimental information together with the updated thermodynamic description for the Ni-Sn binary system. Comprehensive comparison of the calculated and reported thermodynamic properties as well as isothermal and vertical sections shows that the experimental information is satisfactorily reproduced by the present modeling, further validating the thermodynamic descriptions developed in this work.
10.1016-j.calphad.2022.102395	12	thermodynamic; ternary; phase; data; experimental; equilibria; phase equilibria; liquid; binary; experimental data; calculated; phases; literature; model; calphad	The phase equilibria of the Cu-Ti-Nb ternary system were investigated via thermodynamic modeling coupled with key experiments. Fourteen equilibrated alloys were prepared to determine the isothermal sections of the Cu-Ti-Nb system at 600 and 700 degrees C combining X-ray diffraction (XRD) and scanning electron microscopy with energy dispersive X-ray spectroscopy (SEM/EDS), and four as-cast alloys were prepared to study the alloys solidification behavior. The solubilities of Nb in binary compounds of the Cu-Ti system and Cu in the (beta Ti, Nb) phase were measured. No ternary compound was found. The thermodynamic assessment of the Cu-Ti-Nb system was carried out by the CALPHAD (CALculation of PHAse Diagrams) approach based on the thermodynamic descriptions of three constitutive binary systems as well as the experimental phase equilibria data obtained from the present work and literature. The substitutional model and sublattice model were adopted to describe the solution phases and intermediate phases, respectively. A set of self-consistent thermodynamic parameters of the Cu-Ti-Nb system was obtained. The calculated isothermal sections are in good agreement with most of the reliable experimental data. The liquidus projection and reaction scheme of the Cu-Ti-Nb system over the whole composition were also presented. The solidification behaviors of as-cast alloys were described under GulliverScheil non-equilibrium condition. The simulated and experimental results are consistent with each other.
10.1016-j.calphad.2022.102487	12	thermodynamic; ternary; phase; data; experimental; equilibria; phase equilibria; liquid; binary; experimental data; calculated; phases; literature; model; calphad	The phase equilibria of the Cu-Ag-Zr system at 600 and 500 degrees C were determined by X-ray diffraction (XRD) and scanning electron microscope (SEM) with energy dispersive X-ray spectrometry (EDS) techniques. Invariant reactions involving the ternary Cu4AgZr phase were investigated by differential scanning calorimetry (DSC) techniques. Two as-cast alloys were prepared to study the alloys solidification behavior. The solubilities of Cu in the AgZr2 and AgZr phases and of Ag in the Cu5Zr, Cu51Zr14, Cu10Zr7 and CuZr2 phases were measured, and the ternary compound Cu4AgZr was found with compositions of Cu58.70-72.57Ag10.31-21.52Zr16.74-19.78 and Cu58.1875.04Ag6.08-23.36Zr17.50-18.88 at 500 and 600 degrees C, respectively. Seven invariant reactions were determined. By using the CALPHAD (CALculation of PHAse Diagrams) method, thermodynamic assessment of the Cu-Ag-Zr system was carried out based on the available experimental data from the literature and the present work. Substitutional solution model was used to describe the solution phases and sublattice models were used to describe binary and ternary compounds. The ternary compound Cu4AgZr was describe as (Cu, Ag)5(Zr)1. A set of self-consistent thermodynamic parameters of the Cu-Ag-Zr system was obtained. The isothermal sections at 500, 600 and 750 degrees C and liquidus projection were calculated, and the reaction scheme was constructed. The solidification behaviors of as-cast alloys were simulated under Gulliver-Scheil non-equilibrium condition. The calculated phase equilibria and simulated solidification behaviors are in agreement with the experimental data.
10.1016-j.calphad.2023.102581	12	thermodynamic; ternary; phase; data; experimental; equilibria; phase equilibria; liquid; binary; experimental data; calculated; phases; literature; model; calphad	The phase equilibria of the Cu-Cr-Ti ternary system were investigated based on key experiments coupled with thermodynamic modeling. Eighteen ternary alloys were prepared to determine the isothermal sections of the Cu-Cr-Ti system at 600 and 800 degrees C by means of X-ray diffraction (XRD) and scanning electron microscopy equipped with energy dispersive X-ray spectroscopy (SEM/EDS). Seven three-phase regions have been determined. A ternary compound & tau;1 was confirmed. The solubilities of Cr in the Cu-Ti binary compounds and Cu in the Cr-Ti binary compounds were measured. The substitutional and sublattice models were used to describe the solution phases and intermediate phases, respectively. Based on the thermodynamic descriptions of three binary systems as well as the experimental phase equilibria data available from the literature and the present work, thermodynamic assessment of the Cu-Cr-Ti system was carried out using the CALPHAD (CALculation of PHAse Diagrams) approach . A set of thermodynamic parameters was obtained and the isothermal sections and the liquidus projection of the Cu-Cr-Ti system were calculated. The calculated results agree well with the experimental data.
10.1016-j.calphad.2023.102594	12	thermodynamic; ternary; phase; data; experimental; equilibria; phase equilibria; liquid; binary; experimental data; calculated; phases; literature; model; calphad	Several as-cast and annealed Cu-Ti alloys were prepared for microstructural, compositional, structural and thermal characterizations. The formation of CuTi2 was congruent and CuTi3 was not found in both as-cast and annealed specimens. The temperatures of nine invariant reactions were determined. The Cu-Ti system was thermodynamically re-assessed according to the experimental phase equilibria and thermochemical properties from this work and the literature. The solution phases Liquid (L), fcc-A1 (Cu), bcc-A2 (I3Ti) and hcp-A3 (& alpha;Ti) were treated as substitutional ones. The intermetallics compounds Cu2Ti, Cu3Ti2, Cu4Ti3 and CuTi2 with negligible solubility were described as line ones with the formula CupTiq, while I3Cu4Ti and CuTi with remarkable solubility were modeled with the formula (Cu,Ti)r(Cu,Ti)s. A group of reliable thermodynamic parameters of the Cu-Ti system were obtained. The calculated results agreed reasonably well with the experimental ones.
10.1016-j.calphad.2023.102623	12	thermodynamic; ternary; phase; data; experimental; equilibria; phase equilibria; liquid; binary; experimental data; calculated; phases; literature; model; calphad	A viscosity model with composition and temperature dependence for the liquid alloys of the Cu-Cr-X (X = Ni, Si, Zr) systems was developed using the CALPHAD (CALculation of PHAse Diagrams) approach . Based on the critical review of the available experimental data for pure metal viscosity, the viscosities of pure liquid Cu, Cr, Zr, Ni and Si were simulated with the Arrhenius formula. The viscosities of the binary liquid alloys of the Cu-Ni, Cu-Si, Cu-Zr, Cr-Ni, Cr-Si and Ni-Zr systems at different temperatures were evaluated using the CALPHAD-type formalism. The non-linear viscosity behavior resulting from chemical short-range order was described using temperature-dependent binary interaction parameters. The viscosities of the Cu-Cr and Cr-Zr liquid alloys were predicted employing the Hirai equation. The viscosities of the Cu-Cr-Zr, Cu-Cr-Ni and Cu-Cr-Si ternary liquids were directly extrapolated using the Redlish-Kister-Muggianu equation from the parameters of the binary systems. Acomprehensive understanding of the temperature-compositionsolidification phase-viscosity relationship was established for ternary melts. The satisfactory agreement observed between calculations and experimental data validates the use of CALPHAD-type viscosity modeling, supporting the suitability of the constructed viscosity database for predicting the viscosity of high-performance Cu-based alloys.
10.1016-j.calphad.2023.102626	12	thermodynamic; ternary; phase; data; experimental; equilibria; phase equilibria; liquid; binary; experimental data; calculated; phases; literature; model; calphad	In this paper, 6 Cu-Al-Sn ternary and 8 Cu-Ni-Al-Sn quaternary solid diffusion couples within single fcc phase from 1023 K to 1173 K were fabricated. Employing the measured concentration profiles and interdiffusion fluxes, the atomic mobility parameters and interdiffusion coefficients in Cu-Al-Sn and Cu-Ni-Al-Sn systems were high-throughput evaluated using the numerical inverse method. The simulated composition distributions and interdiffusion fluxes in all the diffusion couples are consistent with the measured ones confirming the reliability of the atomic mobilities. The Matano-Kirkaldy method was also used to validate the reliability of the accuracy of the determined interdiffusion matrices. The 3D diagrams of main interdiffusivities in the Cu-Al-Sn and Cu-Ni-Al-Sn systems in the investigated ranges of composition and temperature were established to analyze the effects of components on the diffusivities. In the Cu-Al-Sn system, there is an increase in (D) over tilde (Cu)(AlAl) with an increase in xAl, while (D) over tilde (Cu)(SnSn) increases with increasing x(Sn) but decreases with the addition of Al. Additionally, the introduction of Ni results in a decrease in all the main interdiffusivities ((D) over tilde (Cu)(NiNi), (D) over tilde (Cu)(AlAl) and (D) over tilde (Cu)(SnSn)) in the Cu-Ni-Al-Sn system.
10.1016-j.calphad.2023.102637	12	thermodynamic; ternary; phase; data; experimental; equilibria; phase equilibria; liquid; binary; experimental data; calculated; phases; literature; model; calphad	Critical assessment of the thermodynamic data for pure copper was carried using careful analysis of the existing experimental data. An extended Einstein model was used for the crystalline phase and the two state model was applied for the liquid phase. Special attention is paid in this work to the precise description of the following thermodynamic functions: So298, Ho298-Ho0, the melting temperature, and the entropy and enthalpy of fusion. In order to fullfill the need for a precise evaluation of So298 we needed to use an additional technique, which allows the experimental heat capacity and enthalpy data for the solid phase to be approximated accurately from 0K up to the melting point. Relative stabilities of the BCC_A2 and HCP_A3 phases were derived.
10.1016-j.cap.2019.01.016	-1		Nanoparticles can be added to metals to tune their properties for numerous applications. Recently extensive research has been conducted to measure the mechanical properties of nanoparticle reinforced metals. However, few theories exist to understand how nanoparticles interact with metals to affect their electrical performance, partly due to the difficulty in producing bulk metal samples, containing dispersed nanoparticles. In this work, copper and copper alloys (Cu, Cu-40 wt% Zn, and Cu-60 wt% Ag) containing dispersed tungsten carbide (WC) nanoparticles of more than 20 vol% were successfully fabricated via solidification processing. The experimental results show that copper and its alloys with an increasing volume fraction of nanoparticles, the electrical conductivity of the samples decays exponentially. Therefore, a theoretical model, compatible with the Nordheim's rule was established to predict the electrical behaviour of metals containing dispersed nanoparticles. This new model on the electrical behaviour of copper nanocomposites is experimentally validated by low-temperature resistivity measurements and electronic heat capacity measurements above Debye temperature.
10.1016-j.cap.2021.04.024	-1		Grain boundaries (GBs) relaxation is a promising and effective strategy to improving GB stability or stabilizing nanocrystalline metals. However, previous studies mainly focused on nanocrystalline pure metals and GB behaviors therein, without considering the role of foreign atoms such as impurity or alloying atoms in GB relaxation. In this work, the shear-strain induced structural relaxation of pure Cu Sigma 3 [110](112) symmetric tilt GBs (STGBs), and the effects of foreign elements (Fe and Ni) and temperature on the GB relaxation were investigated in detail by molecular dynamics method. The results show that shear strain can trigger the structural relaxation of pure, Fe- and Ni-containing Cu GBs by the emission of Shockley partial dislocations from Cu GBs. Both Fe and Ni have impediment effects on the shear-strain induced GB relaxation, though the content of Fe or Ni atom (0.00165 at%) is quite low in the GB model. The temperature cannot trigger GB relaxation independently within the considered temperature range, but play a positive role in the shear-strain induced structural relaxations of pure, Fe- and Ni-containing Cu Sigma 3 [110](112) STGBs. Our work might gain new insights into the mechanically induced GB relaxation in nanocrystalline copper and could be beneficial for improving the stability of Cu GBs.
10.1016-j.carbon.2013.11.058	-1		The possibility of using multi-layer graphene (MLG) particles as reinforcement for enhancing the mechanical propertied of Cu matrix composites was explored. The combination of ball milling and high-ratio differential speed rolling (HRDSR) techniques was utilized to fabricate the 0.5 and 1 vol.% MLG/Cu composites. In the HRDSR-processed composites, the nanosized MLG particles with 5-15 nm in diameter were dispersed densely and uniformly in the grain interiors of Cu matrix with a preferred crystallographic relationship of < 111 >(cu)//< 0001 >(MLG) to the matrix. The conventionally rolled composites with the same contents of MLG, however, contained much lower densities of nanosized MLG particles. This result indicates that the large shear strain induced during HRDSR accelerated breaking up of MLGs into nanosizes and enhanced their dispersion in the matrix. The strength improvement through the addition of MLGs was obvious when HRDSR was used, but it was negligible when conventional rolling was used. The strengthening gained through the homogeneous dispersion of high-density nanosized MLG particles in the HRDSR-processed composites was attributed to Orowan strengthening. This finding is different from the HRDSR-processed carbon-nanotube (CNT)/Cu composites studied in our previous work, in which the grain-size reduction through the addition of CNTs was the major contribution to the strengthening effect.
10.1016-j.carbon.2017.01.023	-1		Growth of high quality, monolayer graphene on copper thin films on silicon wafers is a promising approach to large-scale, direct graphene device fabrication. However, the presence of potential dewetting issues in the copper film during graphene growth has historically limited this method of device fabrication. This paper shows that the use of a nickel adhesion layer coupled with the copper film helps to mitigate the dewetting problem and produce uniform monolayer graphene growth over 97% coverage on films. The feasibility of monolayer graphene growth on Cu-Ni alloy films as thin as 150 nm in total is demonstrated. During the graphene growth on Cu-Ni films, the nickel adhesion layer uniformly diffuses into the copper thin film resulting in a Cu-Ni alloy, helping to promote graphene nucleation and large area surface coverage. Furthermore, it was found that the use of extremely thin metal catalyst films also constraint the total amount of carbon that can be absorbed into the film during growth, which helps to eliminate adlayer formation and promote monolayer growth regardless of alloying content, thus improving the monolayer fraction of graphene coverage on the thinner films. These results suggest a path forward for the large scale integration of high quality, monolayer graphene into nanoelectronic and nanomechanical devices.
10.1016-j.carbon.2017.11.033	-1		Copper matrix composites reinforced with graphite flakes (GFs/Cu) were fabricated by powder hot pressing method and the alloying chromium (Cr) element in powdered form was directly added into the Cu matrix powder to enhance the interfacial bonding between GFs and Cu matrix. Effects of addition of Cr on thermal conductivity (TC), coefficient of thermal expansion (CTE), and bendin g strength of GFs/Cu composites in X-Y (basal plane of GF) and Z directions were investigated in this study. The results showed that in X-Y direction, the TC of 50 vol% GFs/Cu composites increased from 560 to 628 W m(-1) K-1 after adding 2.0 wt% Cr, and the bending strength nearly doubled from 53.8 (GF/Cu) to 93 MPa. The CTE in Z direction could be obviously reduced with Cr addition, which dropped gradually from 9.4 to 3.2 ppm K-1 at 150 degrees C with the increase in content of Cr from 0 to 5.0 wt%. This improvement in TC, bending strength, and CTE is attributed to the formation of carbide transition layer at the interface between Cu and graphite. The detailed influence of carbide layer on the properties of the composites was thoroughly studied by corresponding evolution of interfacial microstructure with increasing Cr content.
10.1016-j.carbon.2018.10.088	-1		Corrosion protection of metals is of great importance due to their widespread use. Graphene (Gr) has shown promising corrosion resistance as a coating for metals, however, its excellent strengthening effect that has been widely shown is suppressed in such coating applications. Here, inspired by positive anti-corrosion role of graphene coating for metal macro-foils, graphene encapsulated Cu (Cu@Gr) micro-/nano-flakes are designed and fabricated, and then used as building blocks for assembling bulk Gr/Cu composites. Thanks to its protective role and strengthening effect of uniformly dispersed graphene in Cu matrix, as compared to bare copper, corrosion rate of the as-fabricated bulk Gr/Cu composites is reduced by 50% in NaCl solution and its yield strength is increased by similar to 180% (2.5 vol% Gr) simultaneously, without deterioration on electrical conductivity. The anti-corrosion mechanisms are understood by studying etching behavior of the Cu@Gr flakes in FeCl3 solution, and surface morphology evolution in the samples subjected to salt spray corrosion, and electrochemical corrosion tests. Graphene's anti-corrosion effect is also reflected by an anisotropic corrosion behavior of the Gr/Cu composite because of a brick-and-mortar microstructure. The results presented here shed light on expanding metal matrix composite's applications to a wider range and more complex situation by incorporating graphene.
10.1016-j.carbon.2019.12.097	-1		This paper presents an experimental approach where the effect of Cr and Sn concentrations on the wetting of graphite by molten Cu-xSn-yCr ternary alloys at 1373 K. It shows that a small quantity of Cr addition (<= 2 at%) can improve the wettability significantly owing to the formation of chromium carbides at the interface. Sn addition (x <= 30 at%) can further improve the wettability by decreasing the surface tension. However, higher Sn concentration (x >= 40 at%) will cause the precipitation of main phase at the interface, varying from Cr7C3 to Cr3C2, which in turn will slightly deteriorate the wettability. The phase equilibrium transition point (x approximate to 35% in Cu-xSn-1Cr/C-graphite) is responsible for wettability variation by the increase of Sn concentration. When the Sn concentration is >= 40 at%, the spreading dynamics are satisfied with the assumption of the classical diffusion-limited spreading model. When the Sn concentration is <= 30 at%, the transport route of Cr is from the Sn segregation layer on the drop surface to the triple line rather than from the internal diffusion of the bulk drop to the triple line, and then a precursor film with the specific width can be formed.
10.1016-j.carbon.2021.11.055	-1		Laminated multi-layer graphene/Cu-Al-Mn composites were prepared via packaged hot roll bonding process for the first time. Microscopic observation shows that the grains in the Cu-Al-Mn layers are remarkably refined. Multi-layer graphene films intermittently disperse at the interfaces between Cu-Al -Mn layers. Some small fragments of multi-layer graphene films are squeezed into the Cu-Al-Mn layer, and around them, due to the formation of in-situ Al2O3 phase and nano-twins, multi-stage and multi-phase structures are formed. Performance tests show that the composites have ultrahigh damping capacity. Within a wide temperature range of 25-300 degrees C, the value of damping plateau is up to 0.1 (about 10 times that of the original Cu-Al-Mn alloy). The composites also have superior tensile mechanical properties. Their tensile strength and elongation are up to 913.3 MPa and 13.4% respectively (2.5 times and 4.1 times that of the original Cu-Al-Mn alloy). Microstructural origins of the excellent comprehensive properties were discussed in detail.
10.1016-j.carbon.2022.07.025	-1		Based on practical application requirements, the Cu alloy matrix with precipitates, particularly obstructing dislocation gliding, offers a promising pathway to substantially increase the strength of composites. Unfortunately, the fabrication of nano-precipitates often brings about extensive interface, which typically limits the electronic transmission capability and deteriorates the electrical conductivity. Herein, in-situ synthesized graphene nanoplatelets combined ball milling is deliberately selected to enable robust interfacial bonding and construct analogy-bicontinuous structures through hindering the diffusion of Ag in the Cu-Ag alloy matrix by the graphene nanoplatelets. The Cu alloy matrix composite after heat treatment exhibits a yield strength of similar to 445 MPa and a fracture elongation of similar to 13.5%, which is mainly ascribed to the introduction of the graphene nanoplatelets and the Ag nano-precipitates, and the adjustment of the analogy-bicontinuous structures. Meanwhile, the toughening mechanism of the Cu alloy matrix composite is rationalized on basis of delocalization and crack deflection affected by the graphene nanoplatelets and analogy-bicontinuous structures. Furthermore, the construction of continuous conductive path in the analogy-bicontinuous structures, refraining from the adverse effects caused by interface scattering, is of great benefit to the electrical conductivity, which is elevated to a high level of 92.2 %IACS. The present discoveries shed new insights into the innovative design of the Cu alloy matrix composites for advanced engineering applications by regulating the heterostructure.
10.1016-j.carbon.2025.120365	-1		It is a great challenge for the laser-based additive manufacturing of complex copper (Cu) alloy components with high strength and high conductivity due to the low energy absorption rate from their high optical reflectivity and thermal conductivity. In this work, the additive manufacturing Cu alloy with high strength and flexibility, and excellent conductivity was fabricated by doping CuCrZr powder with GNSs. At a GNSs addition level of 0.075 wt%, elongation, tensile strength, and thermal and electrical conductivities of Cu alloy are improved by over 40 %. To reveal the enhancement mechanism of these physical and mechanical properties, both experiment and crystal plasticity modeling were applied to investigate the microstructure and deformation behaviors of these Cu alloys. It is found that the introduction of GNSs enhances laser absorption, thereby resulting in the nucleation and growth of large amounts of slender columnar grains that boost thermal and electrical conductivities. Moreover, the addition of GNSs also induces the formation of fine and dispersed precipitates with high-density dislocation tangles, thereby leading to improved alloy strength . Additionally, increased laser absorption also affects the texture components, which significantly enhances the ductility of Cu alloys. This study demonstrates a method to achieve Cu alloys with high performances by using laser-based additive manufacturing and can promote the application of additive manufacturing of copper alloys.
10.1016-j.carbon.2025.120654	-1		Due to the substantial disparity in density and absence of wettability at the interface between Cu and C, it's a significant challenge to uniformly disperse carbon fillers through traditional casting. This study introduces a novel technique termed turbulence-shock homogeneous casting to fabricate Cu-0.5Cr-0.5Zr (wt%)/Carbon fibers composites successfully. Experimental results show that when rotational speed reaches 800 rpm and fiber content is 18 vol%, the in-plane and through-plane thermal conductivity of the composite is 562 W m-1 K-1 and 547 W m-1 K-1 respectively. The supergravity effect drives the alloy melt to generate high-speed turbulence, which not only impinges and disperses fiber agglomerates, but also greatly enhances mass transfer efficiency of the melt and facilitates comprehensive interfacial reactions between modified elements and carbon fibers. In-situ formation of Cu/Cr3C2(ZrC)/C heterogeneous interfaces greatly improves wettability of Cu/C interfaces and ensures uniform dispersion of fibers and formation of 3D interconnected carbon fiber networks in the Cu matrix after solidification of the melt. A modified Agari model is developed to analyze thermal conductivity of the composites. Results show that interconnected thermal conductive carbon fiber networks and low thermal resistance Cu/Cr3C2(ZrC)/C heterogeneous interfaces are primary reasons for the exceptional thermal conductivity of the composites.
10.1016-j.cep.2022.108813	-1		Waste printed circuit boards (WPCBs) present serious threats to the environment but also the opportunity to recover the valuable metals, motivating a search for processes to allow their cost-effective recycling. In this regard, the advantages afforded by liquation crystallization and supergravity technology were combined herein to develop a new supergravity-enhanced liquation crystallization process for recovering metals from WPCBs. The WPCB particles were fully smelted to obtain WPCB alloy. Fe-rich, Cu-Zn, Cu-Sn, and Pb-rich phases were progressively precipitated from the alloy melt as the temperature decreased and subsequently stratified from top to bottom after supergravity-induced enrichment owing to their different densities. Fe-rich, Cu-Zn, Cu-Sn, and Pb-rich alloys were obtained via supergravity-assisted separation at 1100, 850, and 500 degrees C, respectively. The mass fractions of Fe in the Fe-rich alloy, (Cu + Zn) in the Cu-Zn alloy, (Cu + Sn) in the Cu-Sn alloy, and Pb in the Pb-rich alloy reached 81.8 wt%, 92.9 wt%, 91.2 wt%, and 94.6 wt%, respectively, in the three separation steps. The final recoveries of Fe, Cu, Zn, Sn, and Pb after three supergravity-assisted separation stages reached 98.8%, 97.8%, 94.1%, 96.9%, and 97.4%, respectively. This study demonstrates an efficient method for sepa-rating metals from WPCBs and improving the grade of the separated metals.
10.1016-j.cep.2023.109483	-1		Supergravity technology is an efficient method to remove trace impurities and recycle valuable components from secondary sources. This study investigated the enrichment and separation behaviors of impurities from simulated Cu alloys that based on the typical impurity compositions (such as Pb, Fe, Sn, Al, and inclusions) of waste stripped copper wire using supergravity technology. After supergravity enrichment, nonmetallic inclusions and Fe impurity were concentrated in the top of the sample, and the enrichment degree positively correlated with the gravity coefficient. The low-melting-point impurities in Cu alloys were separated by supergravity. Improving the gravity coefficient and temperature benefited the removal of Pb and Sn but had negative influence on the re-covery of Cu. Ultimately, the removal rates of Fe, Sn, and Pb were 79.1%, 39.8%, and 74.4%, respectively, and the recovery of Cu was 91.2% under the optimal conditions. Based on these results, supergravity technology is feasible for purification of Cu alloy and achieves good application. It has provided theoretical foundation for recycling of high purity copper and also pointed out a green and efficient way for recycling waste stripped copper wire that can improve resource utilization and prevent environmental damage.
10.1016-j.ceramint.2017.01.056	-1		Cu-SiC composites are very promising materials which have high thermal and electrical conductivity and may find many applications. Unfortunately, the main disadvantage of these materials is the dissolution of silicon in copper at elevated temperature, which significantly reduces their properties. In order to overcome this problem particles can be coated with a protective material before sintering. In this paper the influence of three different metallic coatings on bonding strength were investigated. SiC particles were coated with tungsten, chromium or titanium. As reference a material with uncoated particles was prepared. The experiments were carried out with the use of microtensile tester. The highest increase in strength was observed in the case of chromium coating. On the other hand, the titanium coating, which was of very poor quality, decrease the bonding strength in comparison with uncoated particles. Furthermore, scanning electron and optical microscopes were used to determine the mechanism of debonding.
10.1016-j.ceramint.2017.03.083	-1		Structural, mechanical and thermodynamic properties, as well as the electronic structures of Cu-Ti binary system intermetallic compounds in Ag-Cu-Ti and Cu-Ni-Ti active filler metals were calculated systematically using a first-principles density functional theory (DFT). The calculated formation enthalpy index that all the Cu-Ti intermetallic compounds are thermodynamic stable from degradation to pure metals and the relationship between Cu content (x) and formation enthalpy (y) for tetragonal structure meets the function y=0.572+(-1.005/(0.048*sqrt(3.142/2)))*exp(-0.5*((x-47.167)/13.533)<^>2). The mechanical properties, including bulk modulus B, shear modulus G, Young's modulus E and Poisson's ratio v, and elastic anisotropy were derived from the elastic data C-ij. For the tetragonal Cu-Ti intermetallic compounds, the shear modulus G and Young's modulus E are negatively related to the formation enthalpy, while for the orthorhombic Cu-Ti intermetallic compounds, G and E are positively related to the formation enthalpy. Moreover, the elastic anisotropy increases in the following order: Cu4Ti < CuTi3 < Cu4Ti3 < Cu2Ti < CuTi < CuTi2 < Cu3Ti2. The thermodynamic properties were estimated from the electronic structures and elastic constants simultaneously, and the results found that Cu4Ti possess the best thermal conductivity and heat capacity among all the Cu-Ti intermetallic compounds, while CuTi3 shows the worst ones. Finally, the relationship between electronic structures and physical properties was discussed, and get the inference that for the Cu-Ti intermetallic compounds, the mechanical properties are positively related to the strength of the covalent bond, while the thermophysical properties are influenced by the ionic character and covalent character simultaneously and the ionic character shows the dominant role, therefore, CuTi and Cu4Ti3 show the strongest mechanical properties due to the strongest covalent character, while Cu4Ti shows the strongest thermal conductivity and heat capacity due to the strongest ionic character.
10.1016-j.ceramint.2017.06.153	16	wear; composite; composites; powders; milling; particles; powder; wt; sliding; friction; hardness; matrix; mechanical; surface; properties	To improve the mechanical properties of sintered Cu-matrix composites, nano ZrO2 was added up to 12 wt-% and the mechanical alloying technique was used for preparation. After milling, the nanocomposite powders were investigated by X-ray diffraction and transmission electron microscopy. The prepared nanocomposite powders were cold pressed and sintered for 1 h at 750 and 850 degrees C. Furthermore, the microstructure of the sintered specimens was examined by scanning electron microscopy. Moreover, physical, mechanical and electrical properties of sintered specimens were investigated. TEM investigation of the milled powders exhibited homogeneous morphology and particle sizes. Also, it indicated that as the ZrO2 content increases, more uniform distribution of nano-sized ZrO2 particles in the Cu-matrix was achieved and a decrease in the particle size could be obtained. The crystallite size and particle size were decreased and reached to 10.76 and 32.22 nm, respectively, for Cu-12 wt-%wt% ZrO2 nanocomposite. The results revealed also that the microhardness, compressive strength and yield strength of the nanocomposites were increased with increasing of ZrO2 content except fracture strain that reduced significantly. Moreover, all mechanical properties were enhanced much more with the increase of sintering temperature. The electrical conductivity was decreased with the increase of ZrO2 content while it increased with the increase of sintering temperature.
10.1016-j.ceramint.2017.09.053	-1		Novel friction composites (C/C-Cu5Si-TiC) were prepared via reactive melt infiltration (RMI) of Cu-Ti alloy into porous C/C-SiC composites. The microstructure, physical properties and tribological behaviors of the novel material were studied. Results were compared to conventional C/C-SiC composites produced by liquid silicon infiltration(LSI). The resultant composite showed the microstructure composed of Cu5Si matrix reinforced with TiC particles and intact C/C structures. Most importantly, the composite did not present traces of free Si. As a result, the C/C-Cu5Si-TiC composite showed higher flexural strength, impact toughness and thermal diffusivity in comparison to C/C-SiC composites. Tribological properties were measured using 30CrSiMoVA as a counterpart. In general, the C/C-Cu5Si-TiC composites showed lower coefficient of friction(COF), but higher wear resistance and frictional stability. The improved wear resistance of the C/C-Cu5Si-TiC composites is credited to the formation of friction films from Cu5Si matrix. Other deformation and wear mechanisms are also described considering the microstructural observations.
10.1016-j.ceramint.2017.11.080	-1		In this study, the effect of ceramic nanoparticles addition on the microstructure and texture of friction stir processed (FSP) copper has been investigated. For this purpose, two pure copper plates with and without Al2O3 nanoparticles were FSPed at rotational speed of 800 rpm and traverse speed of 100 mm min(-1). Electron back scattered diffraction (EBSD) technique was employed in order to study the microstructure and texture of the fabricated samples. Based on the obtained results, considerable grain refinement by dynamic recrystallization (DRX) mechanism was observed in both specimens. However, Al2O3 inset led to evolution of ultrafine grained (UFG) structure with an average grain size of 0.7 mu m. In addition, Al2O3 addition caused formation of lower twin boundaries and stronger texture components compared with the sample without ceramic reinforcements. The presence of nanoparticles increased the proportion of the continuous DRX mechanism (CDRX) compared to the discontinuous mechanism (DDRX) during grain structure formation.
10.1016-j.ceramint.2018.08.087	-1		Al2O3/Cu-O composites were fabricated from the paper-derived alumina matrix infiltrated with a Cu-3.2 wt% O alloy. Paper-derived alumina preforms with an open porosity ranging from similar to 14 to similar to 25 vol% were prepared by sintering of alumina-loaded preceramic papers at 1600 degrees C for 4 h . Pressureless infiltration at 1320 degrees C for 4 h of the preforms with Cu-O alloy resulted in the nearly dense materials with good mechanical and electrical properties, e.g. fracture toughness up to 6 MPa m(0.5), four-point-bending strength up to 342 MPa, Young's modulus up to 281 GPa and electrical conductivity up to 2 MS/m depending on the volume fraction of copper alloy in the composites. The technological capability of this approach was demonstrated using prototypes in various engineering fields fabricated by lamination, corrugating and Laminated Object Manufacturing (LOM) methods.
10.1016-j.ceramint.2018.08.316	16	wear; composite; composites; powders; milling; particles; powder; wt; sliding; friction; hardness; matrix; mechanical; surface; properties	For the first time, TiC-C/Cu nanocomposites were fabricated from a mixture of Cu, Ti and C powders by the use of different carbon sources (graphite, carbon nanotube (CNT) and graphene) through two-step high energy mechanical milling and in-situ synthesis by annealing, to study the effect of carbon source on phases formation and tribological properties. The results showed the presence of Cu as the matrix, TiC and unreacted carbon phases in the microstructure of sintered samples, and relatively uniform distribution of the reinforcement phase in the copper matrix was obtained. With the decrease of carbon source size, the density of sintered nano-composites was reduced. It was revealed that using the CNT and graphene as carbon sources results in finer TiC nanoparticles, which considerably improves the tribological properties of the nanocomposite. Using CNT and graphene as carbon sources led to 15% and 49% reduction in wear volume loss and 16% and 6% decrease in friction coefficient respectively, in compassion to using graphite.
10.1016-j.ceramint.2018.12.053	16	wear; composite; composites; powders; milling; particles; powder; wt; sliding; friction; hardness; matrix; mechanical; surface; properties	In this paper, copper matrix nanocomposites reinforced by 5 and 10 wt% ZrO2 particles were produced by mechanical milling technique at different milling times. The produced nanocomposite powders were investigated by X-ray diffraction technique and transmission electron microscopy. The effect of high energy ball milling on the morphology, microstructure and microhardness of the produced composites has been investigated. After that cold compaction was applied to the prepared powders under a pressure of 700 MPa and sintered at 950 degrees C for 2 h in hydrogen atmosphere. The results showed that increasing milling time improves microhardness of the prepared nanocomposites. The microhardness of Cu-10%ZrO2 after 20 h milling is 3.76 times larger than pure Cu. This improvement is attributed firstly to the presence of ZrO2 nanoparticles in addition to the improvement coming from the grain refinement and crystallite size reduction occurred due to mechanical alloying. So, in spite of the crystallite size of Cu-10%ZrO2 nanocomposite is reduced to 10.75 nm compared to 105.5 nm for pure Cu, the presence of ZrO2 nanoparticles plays a major role on mechanical properties improvement.
10.1016-j.ceramint.2019.03.043	-1		Nacre-inspired laminated composites have been proven to possess a unique combination of strength and toughness. In this study, we fabricated nacre-mimetic Cu/TiC composites via unidirectional freezing of aqueous TiC slurries containing different amounts of NiO additives, followed by ice sublimation, carbothermal reduction of NiO to Ni during sintering and then gas-pressure infiltration of the Cu melt. The introduction of Ni greatly facilitated the densification of ceramic lamellae and enhanced the interfacial bonding between Cu and TiC. The resultant composites displayed outstanding damage tolerance and anisotropic electrical conductivities. Specifically, for an similar to 31 vol% TiC-Cu composite containing 24 wt% Ni in the ceramic lamellae (based on the TiC content), a fracture toughness (K-Jc) of 72.5 +/- 1.0 MPa.m(1/2), work of fracture of 53.4 +/- 3.5 kJ/m(2), bending strength of 725 +/- 11 MPa and longitudinal electrical conductivity of 22.7 MS/m (similar to 60% of the Cu matrix) were achieved, which were approx. 81%, 536%, 122% and 97% higher than those of the Ni-free composite, respectively. Noticeable toughening was demonstrated to be a consequence of multiple cracking, plastic deformation and uncracked-ligament bridging of the metal layers, as well as crack deflection and blunting. On the other hand, significant strengthening resulted from tailoring the microstructures in the ceramic layers and at the Cu/TiC interface as a result of Ni doping. We believe that the facile strategy adopted herein provides an effective way to solve the problems of wetting and bonding related to metal infiltration and can be readily extended to the preparation of other nacre-inspired metal-ceramic composites.
10.1016-j.ceramint.2019.03.181	17	wear; composites; coating; friction; composite; coatings; surface; tribological; properties; wear resistance; resistance; powder; sliding; matrix; wear rate	In this study, cubic boron nitride (CBN) abrasive segment specimens were produced via high vacuum brazing using Cu-Sn-Ti composite alloys containing tungsten carbide reinforcing particles. The specimen microstructures and interfacial analysis of the brazed CBN grain were characterized by scanning electron microscopy (SEM), energy dispersive spectroscopy (EDS), and X-ray diffraction (XRD). The mechanical properties of hardness, wear resistance, and three-point bending strength of the fabricated specimens were tested. The specimen shape brazed using the composite Cu-Sn-Ti alloy was better than that of the specimen brazed using the pure Cu-Sn-Ti alloy. TiN and TiB2 phases were maintained between the brazed CBN and composite alloys. Meanwhile, TiC compounds were generated between the alloys and WC particles. The hardness of the specimens increased with increasing WC particle content. However, the S25 specimen containing 25 wt% WC particles, exhibited the highest wear resistance and bending strength, increasing by 26.5% and 25.6%, respectively, compared with those of the CBN segment specimen brazed using pure Cu-Sn-Ti alloy. This study provides strategies for developing multilayer brazing CBN abrasive tools.
10.1016-j.ceramint.2020.02.142	16	wear; composite; composites; powders; milling; particles; powder; wt; sliding; friction; hardness; matrix; mechanical; surface; properties	The reduced graphene oxide (rGO) decorated with Ag nanoparticles was synthesized by the chemical reduction of graphene oxide in an aqueous solution containing AgNO3, in the presence of hydrazine hydrate as a reducing agent. The reduction of graphene oxide was confirmed by FT-IR and raman spectroscopy analyses. The x-ray diffraction pattern and UV-visible investigations demonstrated the formation of Ag particles on the surface of rGO sheets. After successful decoration, the Ag/rGO nano-composite was used as the reinforcement in the copper matrix composite. Cu-Ag/rGO composites with different percentages of Ag/rGO (0.4, 0.8, 1.6 and 3.2 vol%.) were prepared by mechanical milling and spark plasma sintering (SPS). The effects of the Ag/rGO content on the consolidation process, micro-hardness, bending strength and also, fracture surface of the prepared samples were then investigated. The three-point bending strength of the sintered samples was increased from 285 to 472 MPa by the addition 0.8 vol%. of Ag/rGO, as compared to the pure Cu. Moreover, increasing the reinforcement content to the 3.2 vol%. Ag/rGO led to decreasing the bending strength to 433 MPa. The highest micro-hardness (81 HV) was obtained for the composite sample containing the 1.6 vol%. Ag/rGO. By increasing Ag/r-GO as the reinforcement (3.2 vol%.), the Vickers hardness was decreased to 69 HV. Also, investigation of the fracture surface morphology showed transformation of fracture mechanism from plastic changes to brittle ones by raising the Ag/rGO content volume from 0.8 to 1.6 vol %.
10.1016-j.ceramint.2021.11.185	-1		Chemical-based synthesis of co-formed oxide (CuO-NiO-Al2O3) nanoparticles, followed by selective hydrogen reduction of the Cu and Ni oxides and ultimately consolidation into pellets, produced various compositions of Cu-Ni/Al2O3 nanocomposites. Scanning electron microscopy (SEM), X-ray diffraction (XRD) and transmission electron microscopy analyses were used to characterize the powders. The generated powders ranged in size from 20 to 70 nm, with a considerable presence of agglomerates. According to SEM examination, the powders were homogeneous in shape and particle size. Cold pressed nanocomposite powders were sintered for 2 h at 950 degrees C. SEM with energy dispersive spectroscopy (EDS) was also used to study the microstructure of the sintered specimens. In addition, the physical and mechanical properties of sintered specimens were studied. When the Al2O3 content increased, a more uniform distribution of nanosized Al2O3 particles in the Cu-Ni matrix was attained, resulting in a reduction in particle size. The results also demonstrated that as the Al2O3 concentration was raised, the microhardness and compressive strength of the nanocomposites rose by 74% and 67% compared to pure alloy, with the exception of fracture strain, which decreased dramatically.
10.1016-j.ceramint.2022.05.252	-1		In this work, through the study of the obtained Cu-Ti-Si-N intermediate products by controlling the reaction degree of Ti and Si3N4 powder in Cu melts at 1250-1300 degrees C, the effects of different Ti: Si3N4 mass ratios on the microstructure evolution of Ti-Si3N4 reaction in Cu melts were verified. When the mass ratio of Ti: Si3N4 is higher, such as 3.09:1, TiN will cooperate with Ti5Si3 and depend on each other to nucleate and grow to form TiN/Ti5Si3 composites. The formed TiN are spherical and wetted by Ti5Si3 to uniformly disperse in Cu melts. As a result, the TiN-Ti5Si3 hybrid reinforced Cu matrix composites will be formed. However, when the mass ratio of Ti: Si3N4 is lower, such as 1.37:1, Ti and Si3N4 will firstly react to form TiN and Ti-Si liquid. The formed TiN are irregularly polygonal and connect with each other. The Ti-Si liquid will combine with Cu melts to form Cu-Ti-Si liquid and finally form delta Cu4Si, eta Cu3Si and tau(1)-CuSiTi phases during the colling stage. In this case, TiN are difficult to be wetted, and the Ti-Si3N4 compact will keep its original shape and not spread in Cu melts.
10.1016-j.ceramint.2022.06.202	-1		Cu-Y2O3 composites were prepared by a secondary mechanical ball milling process and liquid phase in situ reaction and then sintered by the spark plasma sintering (SPS) consolidation technique. The microstructure and mechanical properties were studied using an X-ray powder diffractometer, scanning electron microscope, tensile tester, and Vickers hardness tester. The results showed that the added yttrium was converted into Y2O3, and the obtained Y2O3 nano-particles were uniformly distributed in the copper matrix, their mean size was 5.0 nm, and the cubic Y2O3 phase was coherent with the copper matrix, which indicated (422)Y2O3// (111) Cu and [011] Y2O3// [112] Cu orientation relationship. With the addition of Y, the mechanical properties of the composite materials were improved, and the hardness of 10 vol% Y2O3 was increased by 192.0%. Its tensile strength increased by 168.2% compared to pure copper.
10.1016-j.ceramint.2023.06.258	17	wear; composites; coating; friction; composite; coatings; surface; tribological; properties; wear resistance; resistance; powder; sliding; matrix; wear rate	Copper impregnated carbon/carbon composite (Cu-C/C composite) was fabricated for novel sliding collector material by weaving carbon fiber, heat treatment and Cu alloy impregnation. The effects of counterpart materials (Fe ball and Cu ball) on friction and wear behaviors were investigated and compared with the result of carbon contact strip used in high-speed railway. Morphology, chemical composition, phase and structure of wear surface and tribolayer were characterized to clarify tribological mechanisms. The results show that friction coefficient follows the order: Cu-C/C composite/Cu ball > carbon contact strip/Fe ball > Cu-C/C composite/Fe ball > carbon contact strip/Cu ball. The carbon crystalline of wear surface appears preferred orientation along the sliding orientation, which is benefit for boundary lubrication. When the counterpart material is Fe ball, Cu-C/C composite is superior to pure carbon strip in mechanical strength, electrical conductivity, wear resistance and friction performance.
10.1016-j.ceramint.2023.08.307	17	wear; composites; coating; friction; composite; coatings; surface; tribological; properties; wear resistance; resistance; powder; sliding; matrix; wear rate	Cu-W composites with high strengths and high conductivities have diverse applications. At present, studies on Cu-W composites with low W content (<50 wt%) are scarce. In this study, Cu-10 wt% W (hereinafter referred to as Cu-10W) composites reinforced by nano-Y2O3 particles with various Y2O3 contents were prepared via ball milling and spark plasma sintering (SPS). The effects of different Y2O3 contents (1, 2 and 3 wt%) on the microstructure and mechanical properties of the composites were studied. The results show that the Y2O3 and W particles were uniformly distributed in the Cu matrix. With increasing Y2O3 content, the distribution of Y2O3 changed from dispersion to agglomeration, and the grain size gradually decreased. The hardness and compressive yield strength increased gradually. In addition, the electrical conductivity was maintained above 81.76 %IACS (as stipulated by the International Annealed Copper Standard). For the Y2O3 content of 2 wt%, the density and relative density of the composites reach the maximum values of 9.18 g/cm(3) and 98.65%, respectively. At this time, the tensile strength reaches 353.8 MPa. The combination between the matrix and Y2O3 was good, and the composites showed the best comprehensive performance.
10.1016-j.ceramint.2023.09.021	-1		The non-wetting of the carbon/copper interface makes the conventional hot-pressing preparation process of copper-impregnated graphite (CIG) composites complex, energy-consuming, and costly. Pressureless infiltration can be achieved by the simultaneous addition of low melting point alloying elements and active elements to the Cu matrix. Given the strong dependence of this process on temperature, a modified sessile drop method was used to investigate the reaction path, spreading and wetting mechanisms of Cu-20Sn-2Cr/graphite system under vacuum at 800-1100 degrees C. The results showed that the equilibrium contact angle theta e decreased from 38 degrees (800 degrees C) to 14 degrees (1100 degrees C), mainly because the microstructure and distribution of the reaction product layer (RPL) were transformed from an in-compact and discontinuous layer composed of irregular Cr3C2 particles to a dense and continuous layer composed of regular nanospheres or nanorod-like Cr7C3 particles. In addition, the spreading mechanism was controlled by the local reaction of [Cr] and [C] atoms at the triple line (TL) at 800 degrees C, and by the diffusion of [Cr] atoms to the front of TL at 900-1100 degrees C. The wetting experiment of the Cu-20Sn-2Cr alloy on the Cr7C3 substrate prepared in situ verified that the Cu-20Sn-2Cr/Cgr system followed the reaction product controlled (RPC) wettability theory.
10.1016-j.ceramint.2023.11.383	-1		Tribological properties at high temperature are an important research aspect for high speed or heavy load situation. This paper is to study the structure effects on the tribological properties of Cu-SiC foam ceramic (SiCf) composites at high temperature. Cu-SiCf composites form two interconnected three-dimensional (3D) network structure, which tribological properties could be controlled by designing SiCf ceramic volume fractions, friction components and mesh size. The results showed that SiCf ceramic has overall enhancement mechanism to Cu alloy and friction components by 3D-structure. Additionally, Cu-SiCf composites have friction properties of high temperature resistance, low wear rate, and stable coefficient of friction (COF).
10.1016-j.ceramint.2024.07.042	14	strength; properties; conductivity; electrical; mechanical; cu-; grain; mpa; electrical conductivity; aging; precipitation; phase; mechanical properties; tensile; phases	This research aims to broaden the scope of self-lubricating wear-resistant coatings for applications in diverse industries such as automotive, metallurgy, power, and aerospace. Employing laser cladding technology, we successfully fabricated high-performance self-lubricating ceramic composite coatings. A comprehensive investigation was conducted to understand the inhibitory effect of Cu on the thermal decomposition of MoS2, 2 , and the study systematically explored the relationship between powder composition, coating structure, and organizational properties. The mechanisms behind friction reduction and wear resistance were unveiled, shedding light on the formation of the MoS2 2 self-lubricating protective film. Research findings reveal that during the laser cladding process, Cu and Ni undergo solid solution, resulting in the formation of the Cu-Ni alloy phase and crystal refinement. The MoS2 2 aggregation area exhibits a fine dendritic structure, while the dispersion area showcases coarse dendritic and cellular crystals. The addition of Cu and MoS2 2 influences the content of the MxCy x C y phase and the thermal decomposition of MoS2. 2 . The incorporation of Cu increases the average coating hardness, whereas MoS2 2 addition decreases it; nevertheless, the Cu/MoS2 2 coating hardness is enhanced by at least 6.4 %. Cu significantly improves the coating's wear resistance, with a relatively smaller impact on friction reduction. MoS2 2 functions as a friction-reducing phase during wear, effectively preventing the peeling of hard phases and reducing the friction coefficient. Cu is uniformly distributed in the coating, experiencing solid solution strengthening, reducing adhesive region areas, and minimizing wear debris generation. MoS2, 2 , although unevenly distributed, forms intermittent lubricating films on the surface. The lubricating film of the Cu/MoS2 2 coating remains stable, preventing mutual contact of the friction surface and concurrently reducing the friction coefficient and wear amount. While the study successfully prepared a self-lubricating ceramic coating with excellent wear resistance, some surface quality defects persist. Further optimization of the preparation method was achieved through ultrasound-assisted technology.
10.1016-j.ceramint.2024.11.287	-1		The unlubricated sliding-wear behaviour of WC cemented carbides fabricated by pressureless infiltration of the Cu-30Mn-1P alloy without and with Ni infiltration aids (in the range of 3-10 wt%) was investigated. Firstly, detailed microstructural characterisation showed that these cemented carbides are all dense and consist of extra coarse WC grains (similar to 62 mu m) embedded into Cu0.96Mn0.04 (with traces of P), plus secondary Mn2P and Mn3P phases segregated at the grain/binder interfaces. When infiltrated with Ni aids, the binder contains Ni solutes and there is also interfacial segregation of NiP2 and Mn3Ni20P6. Secondly, the mechanical characterisation showed that the Ni infiltration aids resulted in stronger and more ductile cemented carbides, with no reduction in hardness below 5 wt% Ni aids. Specifically, it was found that 3 wt% Ni infiltration is optimal, which maximises the strength, ductility, and toughness of these cemented carbides as a consequence of the optimised cohesion of the WC grains in the metal binder. And thirdly, the tribological characterisation against Al2O3 showed that all these cemented carbides are wear-resistant, with specific wear rates increasing with applied load, but in the order of 10(-5) mm(3)/(N.m) or lower. Importantly, it was found that Ni infiltration aids up to 5 wt% are beneficial to the wear resistance of these cemented carbides, but more becomes increasingly detrimental. As for the other mechanical properties, Ni infiltration at 3 wt% also maximised the wear resistance. Detailed microstructural characterisation of the worn surfaces of the cemented carbides revealed that wear took place first by two-body abrasion, in which a tribolayer is formed, and then by three-body abrasion, in which partial removal and formation of the tribolayer occur dynamically over time, with the severity of the abrasions depending on the proportion of Ni infiltration aids and the applied load.
10.1016-j.ceramint.2025.08.369	14	strength; properties; conductivity; electrical; mechanical; cu-; grain; mpa; electrical conductivity; aging; precipitation; phase; mechanical properties; tensile; phases	Porous CBN abrasive tools fabricated via the brazing-dissolution process (BDP) offer notable advantages, such as high interfacial bonding strength and a tunable pore architecture. However, structural deformation during the brazing process can significantly compromise the mechanical performance of the porous composite. Therefore, a comprehensive understanding of the underlying deformation mechanisms during brazing is crucial for mitigating structural instability and for informing the rational design of high-performance porous CBN tools. In this study, porous Cu-Sn-Ti composites were fabricated using the BDP method, and the effects of CBN abrasives and MoS2 particles on the microstructure and mechanical properties were systematically investigated. The results showed that increasing MoS2 content led to a significant rise in the number of small pores and a substantial decline in mechanical properties. Specifically, for specimens without CBN, the flexural strength decreased from 115.79 MPa to 45.73 MPa (approximately 60.52 %), while in the series with CBN, it decreased from 96.49 MPa to 39.83 MPa (about 58.68 %). Elemental analysis showed that the incorporation of CBN abrasives improved the wettability of Cu-Sn-Ti alloys through the formation of TiN and TiB phases at the interface, which in turn altered the flow dynamics of the liquid alloy during brazing. Nevertheless, this enhancement was partially hindered by increasing MoS2 content. The proposed mechanism and microstructural analyses offer a theoretical basis for the rational design of high-performance porous CBN machining tools.
10.1016-j.chemosphere.2017.12.082	2	corrosion; surface; film; electrochemical; films; spectroscopy; layer; current; solution; potential; resistance; composition; x-ray; ions; showed	Fuel biodegradation linked to sulfate reduction can lead to corrosion of the metallic infrastructure in a variety of marine environments. However, the biological stability of emerging biofuels and their potential impact on copper-nickel alloys commonly used in marine systems has not been well documented. Two potential naval biofuels (Camelina-JP5 and Fisher-Tropsch-F76) and their petroleum-derived counterparts (JP5 and F76) were critically assessed in seawater/sediment incubations containing a metal coupon (70/30 Cu-Ni alloy). Relative to a fuel-unamended control (1.2 +/- 0.4 mu M/d), Camelina-JP5 (86.4 +/- 1.6 mu M/ d) and JP5 (77.6 +/- 8.3 M/d) stimulated much higher rates of sulfate reduction than either FT-F76 (11.4 +/- 2.7 mu M/d) or F76 (38.4 +/- 3.7 mu M/d). The general corrosion rate (r(2) = 0.91) and pitting corrosion (r(2) = 0.92) correlated with sulfate loss in these incubations. Despite differences in microbial community structure on the metal or in the aqueous or sediment phases, sulfate reducing bacteria affiliated with Desulfarculaceae and Desulfobacteraceae became predominant upon fuel amendment. The identification of alkylsuccinates and alkylbenzylsuccinates attested to anaerobic metabolism of fuel hydrocarbons. Sequences related to Desulfobulbaceae were highly enriched (34.2-64.8%) on the Cu-Ni metal surface, regardless of whether the incubation received a fuel amendment. These results demonstrate that the anaerobic metabolism of biofuel linked to sulfate reduction can exacerbate the corrosion of Cu-Ni alloys. Given the relative lability of Camelina-JP5, particular precaution should be taken when incorporating this hydroprocessed biofuel into marine environments serviced by a Cu-Ni metallic infrastructure.
10.1016-j.chemosphere.2019.01.193	2	corrosion; surface; film; electrochemical; films; spectroscopy; layer; current; solution; potential; resistance; composition; x-ray; ions; showed	In this present study, the biocorrosion behaviour of Bacillus thuringiensis EN2 and B. oleronius EN9 on copper metal CW024A (Cu) in cooling water system (1% chloride) were evaluated using weight loss, electrochemical impedance spectroscopy (EIS) and surface analysis. In presence of EN2 and EN9, the corrosion rates (CR) were higher, about 0.021 mm/y and 0.032 mm/y than control system (0.004 mm/y). On the other hand, the presence of corrosion inhibitor 2-mercaptopyridine (2-MCP) with bacteria (EN2 and EN9), the biofilm on metal surface was highly inhibited and thus reduces the corrosion rate (CR: 0.004 mm/y). The electrochemical behaviour of CW024A metal was correlated with the adsorbed corrosion inhibitor film and biofilm. Atomic force microscopy (AFM) analysis revealed that the presence of EN2 and EN9 more pits was observed on the metal surface rather than 2-MCP system. EIS confirms the inhibitor act as cathodic type of inhibitor and thus leads to the inhibition of CR. Overall, this work concluded that corrosion inhibitor (2-MCP) inhibits, the bacterial biofilm formation on the metal surface due to the formation of productive layer on metal surface as coordination of N-H bond. Which leads to the reduction of bacterial attachment and thus higher corrosion inhibition efficiency (75%) obtained. This is the first work disclosing the role of 2-MCP formulations as potent anti-bacterial and corrosion inhibition efficiency on copper metal in cooling water tower environment.
10.1016-j.cirp.2010.03.014	-1		Electrical-assisted forming (EAF), where current is directly applied to the workpiece during deformation, has been shown to dramatically reduce the flow stress of the material. In this paper, the effect of altering the Zn content in Cu specimens during EAF is investigated. Varying results were observed depending on if the threshold density, which produces significant reductions in flow stress, was surpassed. Thus, temperature increases due to resistive heating alone are not the cause of the observed effects. Once the threshold current is exceeded, the flow stress reductions increased with increasing Zn content. These results support theories regarding the physical mechanism of EAF as dislocations are able to move past alloying elements more effectively. (C) 2010 CIRP.
10.1016-j.cirpj.2022.03.010	-1		To obtain a pure copper with extraordinary strength-ductility-conductivity balance, asymmetric cryorolling followed by low-temperature (200 degrees C) annealing was employed. The microstructural-mechanical-electrical properties of the samples were investigated. The results showed that multiple twinning was formed after the partial annealing of deformed copper. The copper annealed for 60 min exhibited a hardness, yield strength, and tensile strength of 38.1 HB, 192 MPa, and 422 MPa, respectively, while a large total elongation of 37.2% was obtained. Also, the annealed copper had a larger strain hardening rate at epsilon higher than 0.023 owing to the creation of twin chains. The fracture surface of the 60-min annealed copper was dominated by only ductile dimple features. The post-annealed copper showed an extraordinary electrical conductivity of 99.58%IACS, which is much larger than that for all pure coppers with UTS higher than 400 MPa. It was found that using second phase particles with high electrical conductivity was a better strengthening mechanism than strain hardening and grain boundary strengthening. An extraordinary strength-ductility-conductivity balance was achieved in the current pure copper compared to other pure coppers. This was due to the existence of copper oxide, and the formation of twin chains in the present work.(c) 2022 CIRP.
10.1016-j.cirpj.2022.12.004	-1		The present study is focused on characterizing the microstructure, mechanical properties, and electrical resistance of a novel copper-clad aluminum composite wire. In this regard, the extrusion and wire drawing processes have been used to produce the composite wire. After every deformation step, intermediate an-nealing was performed at a temperature of 300 degrees C for 30 min. The microstructure has been investigated using an optical microscope (OM) and a scanning electron microscope (SEM) equipped with energy dis-persive spectroscopy (EDS). Besides, microhardness and tensile tests were utilized to determine mechanical properties. Also, a micro-ohmmeter was employed to measure the electrical resistance. The findings in-dicated that the composite wire's interface was uniform and homogeneous without evidence of thick and continuous intermetallic compounds (IMCs). A comparison between oxygen-free high conductivity (OFHC) copper and composite wire demonstrated that applying a reduction ratio to 99.6% on the composite wire resulted in electrical conductivity higher than 66.8% IACS. Also, the ultimate tensile and yield strengths were increased 37% and 183%, respectively. The strength improvement was attributed to the fine particle distribution in the aluminum alloy core and the residual stress caused by the different elastic properties of the two materials during deformation.(c) 2022 CIRP.
10.1016-j.cirpj.2025.09.009	14	strength; properties; conductivity; electrical; mechanical; cu-; grain; mpa; electrical conductivity; aging; precipitation; phase; mechanical properties; tensile; phases	A bimodal laminate heterostructure consisting of alternating copper-base (CuCrZr) and nickel-base (Hastelloy X) alloy layers was carefully fabricated via multi-material laser powder bed fusion (MM-LPBF) additive manufacturing approach, employing a custom-designed multi-powder delivery device system and proprietary process-control software. The heterostructure shows a hierarchical architecture with periodically alternating coarse-grained (predominantly Hastelloy X) and fine-grained (primarily CuCrZr) layers, interconnected by transition zones containing mixed grain morphologies. The heterostructural material demonstrates exceptional mechanical performance under building-direction loading, achieving a yield strength of 674.2 MPa, ultimate tensile strength of 756.4 MPa (similar to 92 % of monolithic LPBF-processed Hastelloy X), and elongation of 19.9 %. Crystal plasticity simulations elucidate deformation coordination and strength-ductility synergy mechanisms, while microstructural characterization confirms the bimodal grain structure originates from the LPBF-laser-induced melt pool dynamics and heterogeneous nucleation during the rapid solidification. This study establishes MM-LPBF as a viable approach for manufacturing high-performance, architecturally graded multi-material systems.
10.1016-j.cja.2015.10.014	0	solidification; phase; magnetic; magnetic field; undercooling; field; liquid; separation; peritectic; immiscible; cu-; dendrite; phase separation; microstructure; primary	It is well-known that the application of ultrasound during liquid to solid transitions for alloys can refine the solidification microstructure and thus improves the mechanical properties. However, most published work focuses on single phase dendritic growth, whereas little has been conducted on the multiphase alloys with complicated phase transformations during solidification. In this work, the solidification process of ternary Cu40Sn45Sb15 alloy was realized within intensive ultrasonic field with a resonant frequency of 20 kHz and ultrasound power from 0 W to 1000 W. The ultrasound refines the size of the primary epsilon(Cu3Sn) intermetallic compound by two orders of magnitudes. If the ultrasound power increases to 1000 W, eta(Cu6Sn5) phase nucleates and grows directly from parent liquid phase without the occurrence of periutectic reaction on the top of the alloy sample where the ultrasound intensity is sufficiently high . These microstructural variations lead to the enhancement of compressive strength and elasticity modulus of ternary Cu40Sn45Sb15 alloy. (C) 2015 The Authors. Production and hosting by Elsevier Ltd. on behalf of CSAA & BUAA.
10.1016-j.cja.2017.08.008	-1		Porous Cu-Sn-Ti alumina composites were fabricated by sintering Cu-Sn-Ti alloy powders, graphite particles, and alumina hollow particles agent. The effects of the pore structure and distribution on the composites strength were evaluated. Different pore distributions were modeled by using finite element analysis to investigate the tensile strength of the composites. Furthermore, a fractal analysis-based box-covering algorithm was used on the Cu-Sn-Ti alumina composites topology graphs to better investigate the pore structure and distribution. Results obtained show that different sizes and concentrations of alumina hollow particles could result in different porosities from 20% to 50%. A larger pore size and a higher pore concentration reduce the strength, but provide more space for chip formation as a bonding material of a grinding wheel. The body-centered pore structure of the composites shows the highest stress under a tension load. The original composites topology graphs have been transformed to ordered distributed pore graphs based on the total pore area conservation. The information dimension magnitude difference between the original topology graphs and the ordered distributed circulars graphs is found to be linear with the Cu-Sn-Ti alumina composites strength . A larger difference renders a lower flexural strength, which indicates that uniform ordered distributed pores could benefit the composites strength . (C) 2017 Chinese Society of Aeronautics and Astronautics. Production and hosting by Elsevier Ltd.
10.1016-j.coco.2022.101287	10	composites; nanoparticles; strength; matrix; high; strengthening; particles; conductivity; composite; electrical; mpa; sintering; ods; grains; mechanical	Exploring the influence of reinforcement modification on the localized mechanical instability of composites with heterogeneous grain structure is of great importance for tailoring the comprehensive performance. This work realizes the multi-scale structure adjustment of graphene nanoplatelets reinforced Cu matrix composites by in -situ synthesis and ball mill mixing. It was elucidated that graphene nanoplatelets encapsulated Al2O3 with podlike convex structure enhance the interfacial cohesion and the interaction between reinforcement and matrix with heterogeneous grain, which exerts prominent contribution to the elimination of strength-ductility trade-off. Meanwhile, the composites have good electrical conductivity (96.5 %IACS) due to the strict control of interfacial electron scattering by the encapsulated structure. This novel multiscale structural regulation route shows the capacity of developing composites with the exceptional comprehensive performance towards prospective applications.
10.1016-j.coco.2024.101903	-1		The study presents a novel hybrid deep learning and ensemble learning (DL-EL) model to predict the effects of chemical composition and thermo-mechanical processing on the properties of Cu-Ni-Si alloys. The model integrates various input parameters like chemical composition and thermo-mechanical processing parameters and aims to predict key output properties such as mechanical properties and electrical conductivity. This study addresses gaps in existing research by providing a comprehensive model for Cu-Ni-Si alloys and integrating thermo-mechanical processing parameters with chemical composition in the predictive model. The research demonstrates the model's superior predictive performance, with near-perfect R2 values on both training and test sets. The hybrid DL-EL model was compared with three other machine learning models and its efficacy was assessed using R2 value, offering new insights into the performance of these alloys. A feature importance analysis was conducted to identify the most influential features of the model. This work contributes to the material science field by providing insights into optimizing alloy composition and processing, leveraging machine learning to enhance material design.
10.1016-j.coco.2024.102008	-1		Cu-1.2Ta-0.2Zr-1.5Cr(-1Y) composites were successfully prepared by powder metallurgy method, and the microstructure characterized by equiaxed grains and uniformly dispersed reinforcements can be observed. With the addition of Y, the hybrid reinforcements composed of Cr2Ta 2 Ta intermetallic Laves phases and Y2Zr2O7 2 Zr 2 O 7 oxide particles are significantly refined, and more coherent interfacial structures are obtained, which contributes to the synchronous improvement of strength (YS: 547 MPa, UTS: 645 MPa) and elongation (13.5 %), along with the significantly improved softening resistance. Meanwhile, Cu-1.2Ta-0.2Zr-1.5Cr-1Y composite exhibits the thermal conductivity around 300 W/m.k at elevated temperatures, revealing the excellent combination of mechanical property, thermal conductivity and softening resistance.
10.1016-j.coco.2024.102182	-1		The temperature-rise effect caused by the boom of high-power equipment for communications and transportation brings new challenges to the stress relaxation resistance and tensile properties of Cu wires at elevated temperatures. In order to meet higher property requirements, herein we introduced a graphene reinforced Cu-0.5La alloy (Gr/Cu-0.5La) composite wire prepared by in-situ synthesis and powder metallurgy methods. Thanks to the distribution of in-situ formed graphene and Gr-La2O3 hybrid reinforcements at the grain boundaries, the mechanical properties of the composite wire were improved. The uniformly dispersed graphene at grain boundaries created a strong pinning force, which limited the mobility of the grain boundaries and ultimately improved their thermal stability. Notably, the composite wire exhibits significantly enhanced stress relaxation resistivity, demonstrating advantages over element doping strategy. Meanwhile, the electrical conductivity of the Gr/Cu-0.5La composite wire reaches 89.3 % IACS, accompanied by a reduced temperature coefficient of resistance. Cyclic stress relaxation tests revealed that the excellent high-temperature mechanical properties mainly come from the dislocation-controlled strengthening and deformation mechanisms. The excellent comprehensive performance achieved proposes the good application prospects of Gr/Cu-0.5La composite wire in a wide temperature range.
10.1016-j.coco.2025.102274	10	composites; nanoparticles; strength; matrix; high; strengthening; particles; conductivity; composite; electrical; mpa; sintering; ods; grains; mechanical	Interfacial coherency is not taken into account in the strengthening mechanism of oxide dispersion-strengthened materials due to the general cognition that the added ceramic particles cannot maintain a coherent relationship with the matrix. In this work, coherent YbAlO3 and non-coherent Al2O3 dispersion-strengthened Cu composites with the similar size and density of dispersoids were fabricated using mechanical alloying and spark plasma sintering. Dispersion strengthening effects at different temperatures were analyses in the Cu-Al2O3 and Cu- YbAlO3 composites to investigate the effects of interfacial coherency on the Orowan strengthening at high temperatures. Based on the results, interfacial coherency of inert dispersoids affects strengthening effects and coherent dispersoids can provide higher strengthening effects at high temperatures (>0.5T(m)), which is meaningful for the designing of dispersion-strengthened materials serving at high temperatures.
10.1016-j.colsurfa.2018.08.044	2	corrosion; surface; film; electrochemical; films; spectroscopy; layer; current; solution; potential; resistance; composition; x-ray; ions; showed	Superhydrophobic surfaces have a wide application prospect in the future industrial production due to its special abilities. The fabrication of superhydrophobic coating on metal surfaces can improve its performance. A one-step electrodeposition method is proposed to construct nanostructures on the surface of beryllium copper (Be-Cu) alloys, and a mixture of copper chloride and stearic acid is used as the electrolytes. The static contact angle of water on the surface can reach up to 163 +/- 4 degrees, a sliding angle of 1.7 +/- 0.2 degrees. The nanostructure and chemical composition on the surface were evaluated by scanning electron microscopy and X-ray photoelectron spectroscopy respectively. The corrosion resistance was tested through electrochemical measurement. It was found that the as-prepared superhydrophobic coating improved the corrosion resistance significantly. In addition, the coating with excellent self-cleaning performance was proved. This method solves the problems of complicated process, improves the efficiency effectively, and the electrolyte is eco-friendly.
10.1016-j.colsurfa.2020.125653	2	corrosion; surface; film; electrochemical; films; spectroscopy; layer; current; solution; potential; resistance; composition; x-ray; ions; showed	In an attempt to search for high performance, effective and ecofriendly corrosion inhibitors, the macrocyclic compartmental ligand: (2E)-3,6,10,13-tetramethyl-2,7,9,14-tetraaza-1,8(1,4)dibenzena cyclotetradecaphane2,6,9,13-tetraene (PDHDH) and its Ni (II), Cu (II) complexes have been synthesized and characterized by elemental and spectroscopic techniques. For corrosion inhibition studies of Cu10Ni alloy, different concentrations of synthesized inhibitors were added to 3.5 % NaCl as corrosive media and surveyed by potentiodynamic polarization (PDP), electrochemical impedance spectroscopy (EIS) and electrochemical frequency modulation (EFM) techniques. The surface of alloy samples treated with these inhibitors was analyzed by scanning electron microscope (SEM) and X-ray photoelectron spectroscopy (XPS) to confirm the existence of adsorbed protected film. PDP curves showed that the PDHDH and its Ni (II), Cu (II) complexes behave as mixed type inhibitors. The data demonstrated that the synthesized inhibitors could assist as active inhibitors for Cu10Ni alloy corrosion in 3.5 % NaCl solutions and their protection capacity reached to 95.7 % at 100 mu M additive concentration. The synthesized inhibitors obey Freundlich adsorption isotherm, furthermore, the adsorption of these inhibitors on Cu10Ni is physisorption. DFT calculations, Fukui indices, Mulliken atomic charges and molecular electrostatic potential (MEP) mapping were accomplished to support the adsorption features and the corrosion inhibition mechanism of the investigated inhibitors.
10.1016-j.colsurfa.2021.126337	-1		Finding efficient ways to prohibit abiotic and microbiologically influenced corrosion is a critical task for metal serving in harsh seawater environment. In this paper, originated from the biomimetics principle, a lotus leaf inspired superhydrophobic matrix composed by Fe-myristic acid compound is prepared on copper surface. The preparation is realized by a facile electrodeposition approach based on a coordination-deposition mechanism, which leads to porous structure composed of hydrophobic compound from an ethanol bath via a single step. The dependent relationship between wettability and electrodeposition conditions including electrodeposition potential and time is revealed. Sophisticated techniques including scanning electron microscopy, X-ray photoelectron spectroscopy and Fourier Transform infrared spectroscopy are employed to characterize the matrix morphology and composition. Scanning Kelvin probe and other electrochemical methods show that super hydrophobic matrix improves the corrosion resistance capability of copper in different environments including atmosphere, natural seawater and salt spray, illustrating that superhydrophobic matrix endows high abiotic corrosion inhibition to the underneath Cu metal. The inhibition efficiency of Cu by superhydrophobic coating can reach 99.85 % after immersion in seawater for 28 days. For achieving high prohibition effect to the corrosion induced by microbes, the bio-adhesion inhibition is one prerequisite. The as-obtained superhydrophobic matrix is confirmed to prohibit the representative diatoms and sulfate reducing bacteria (SRB) to grow onto metal surface due to the limited anchoring sites and the low surface energy. Superhydrophobic matrix exhibits excellent corrosion resistance in harsh SRB suspension, demonstrating a prominent role to combat microbiologically influenced corrosion in seawater environment. Finding efficient ways to prohibit abiotic and microbiologically influenced corrosion is a critical task for metal serving in harsh seawater environment. In this paper, originated from the biomimetics principle, a lotus leaf inspired superhydrophobic matrix composed by Fe-myristic acid compound is prepared on copper surface. The preparation is realized by a facile electrodeposition approach based on a coordination-deposition mechanism, which leads to porous structure composed of hydrophobic compound from an ethanol bath via a single step. The dependent relationship between wettability and electrodeposition conditions including electrodeposition potential and time is revealed. Sophisticated techniques including scanning electron microscopy, X-ray photoelectron spectroscopy and Fourier Transform infrared spectroscopy are employed to characterize the matrix morphology and composition. Scanning Kelvin probe and other electrochemical methods show that superhydrophobic matrix improves the corrosion resistance capability of copper in different environments including atmosphere, natural seawater and salt spray, illustrating that superhydrophobic matrix endows high abiotic corrosion inhibition to the underneath Cu metal. The inhibition efficiency of Cu by superhydrophobic coating can reach 99.85 % after immersion in seawater for 28 days. For achieving high prohibition effect to the corrosion induced by microbes, the bio-adhesion inhibition is one prerequisite. The as-obtained superhydrophobic matrix is confirmed to prohibit the representative diatoms and sulfate reducing bacteria (SRB) to grow onto metal surface due to the limited anchoring sites and the low surface energy. Superhydrophobic matrix exhibits excellent corrosion resistance in harsh SRB suspension, demonstrating a prominent role to combat microbio
10.1016-j.colsurfa.2021.128220	-1		The superhydrophobic layers were prepared simultaneously on the copper-based cathode and anode surface by one-step electrodeposition. During the electrodeposition process, the reactions on the surfaces of copper-based cathode/anode electrodes were different, therefore different superhydrophobic layers were formed on cathode/anode surface. The wettability, surface morphology and chemical composition were characterized by contact angle measurement, scanning electron microscopy, fourier transform infrared spectroscopy and X-ray photoelectron spectroscopy. The formation mechanism and anti-icing performance of the superhydmphobic layers were explored. Superhydmphobic Cu [CH3(CH2)(16)COO](2) films with dendritic micro/nano hierarchical structure and superhydmphobic Cu2O-stearic acid films with cubic crystal-like micro/nano hierarchical structure were prepared on the surface of the anode and cathodic copper electrode respectively. When the deposition voltage was 4 V and the deposition time was 30 min, the static contact angle reached a maximum of 151.3 degrees on the anode surface and 154 degrees on the cathode surface. Both superhydrophobic films can effectively slow down the icing time. The icing delay effect of the superhydrophobic film on the cathode copper is better, and the delay time was up to 221 s, compared to the original copper surface.
10.1016-j.colsurfa.2022.128282	-1		Ultraviolet laser-ablated technique was used to improve the anti-icing and antibacterial properties of copper (Cu) with the objective of achieving efficient heat exchange performance. The laser scanning space interval exhibited a critical influence on the surface topography. SEM observation showed that nano-villi-like products appeared on the surface, which resulted in the formation of a micro/nano-hierarchical structure when the scanning interval was below 40 mu m. When the scanning space interval was above 40 mu m, the surface presented only a micron-level papilla/groove pattern without any nano-villi-like product. Combined analysis of XRD, TEM, and XPS results indicated that the nano-villi products were partially crystallized copper oxide particles with 5-10 nm size. It was speculated that nano-oxide was obtained by vapor deposition of Cu caused by laser ablation. Furthermore, after modification with FAS-17, the hydrophobicity of the nano-villi-like surface became significantly higher than that of the papilla/groove surface. The highest water contact angle reached 156.30 & PLUSMN; 0.53 and the water sliding angle was as low as 1.57 & PLUSMN; 0.99. In the anti-icing test at -10 C, the delayed freezing time of this superhydrophobic surface reached 9923 s. This excellent anti-icing property can be attributed to the improvement in critical activation energy for ice nucleation and reduction in interfacial thermal conductivity caused by superhydrophobic surface. Finally, the inhibition zone test proved that laser ablation could significantly improve the antibacterial activity of Cu against E. coli and S. aureus.
10.1016-j.colsurfa.2024.133321	2	corrosion; surface; film; electrochemical; films; spectroscopy; layer; current; solution; potential; resistance; composition; x-ray; ions; showed	Galvanic deposition of copper, tin and their alloys is widely used in microelectronics, printed circuit boards, anticorrosive and decorative finishing of products for various purposes. One of the main factors determining the structural and morphological characteristics of the deposited coatings is the value of cathodic polarization during the deposition, which depends on the presence of complexing ions and surfactants. Complexation is one of the most effective and widespread ways to increase the cathodic polarization, as well as the convergence of deposition potentials of copper and tin. In this work we studied the combined effect of thiourea and N-octylpyr- idinium bromide additives on the kinetics of Cu, Sn, and Cu-Sn electrocrystallization from sulfuric acid electrolytes. The combined presence of these additives allows obtaining homogeneous and fine-grained Cu-Sn coatings. The results of theoretical studies agree well with experimental data and show that the introduction of thiourea and N-octylpyridinium bromide leads to the inhibition of cathodic reduction of hydrated copper(II) and tin(II) ions.
10.1016-j.colsurfa.2025.137730	-1		This study explores a novel approach to reducing icing effects by utilizing latent heat release from the icing process or crystallographic transformations. We focus on a Cu-Al-Ni-B shape memory alloy, highlighting its potential for anti-icing applications. We investigated the structural, mechanical, water-repellent, and anti-icing properties (ice adhesion strength and delay in icing time) of Cu-Al-Ni-B-PTFE alloy powder's coatings deposited via high-velocity-oxy-fuel (HVOF) thermal spray under various parameters. The FCC-structured coatings exhibited a high microhardness value of 256 HV. The HVOF-deposited Cu-Al-Ni-B-PTFE coatings displayed three types of water repellence based on contact angle (CA): superhydrophobic (SH-Pho; CA:155 degrees), hydrophobic (H-Pho; CA:120 degrees), and hydrophilic (H-Phil; CA:65 degrees). Surface roughness played a crucial role in delaying icing on water droplets in condensation frost environments. The maximum surface roughness observed in the H-Phil coating contributed to the preservation of an air pocket even after condensation frost, resulting in a delay in icing. All deposited coatings demonstrated an ice adhesion strength (shear) below 70 kPa, indicating excellent anti-icing properties. A comparison of the ice adhesion strength of our (CSIR-NML) developed Cu-based alloy coatings with commercially available paints revealed that our coatings exhibit significantly lower ice adhesion shear strength .
10.1016-j.commatsci.2004.11.021	-1		The work is focused on the neutronic calculation of the nuclear parameters (distribution of neutron fluency, atomic displacement, nuclear heating, gas production, photon production, nuclear reactions and induced activity) in a specimen of the cooper alloy (CuCrZr) using Monte Carlo Neutron-Particle Transport code MCNP-4C2. This alloy is currently one of the best candidate materials for the first wall of the International Thermonuclear Experimental Reactor (ITER) which will be exposed to high neutron load with energy of about 14.1 MeV. The MCNP model of the investigated specimen (12 x 12 x 0.5 mm) consists of 4.683% Cu, 0.754% Cr, 0.163% Zr and 0.4% Cs. The number of primary knock-out atoms calculated for this alloy specimen is 8.253E-02 atoms/source neutron cm(3)). The calculated helium production is 2.857E-03 atoms/(source neutron cm(3)), and the hydrogen production is 1.387E-02 atoms/(source neutron cm(3)). Activity of the specimen by copper activation is of about 5 MBq. The TRIM 98.01 code has been used for the simulation of defects creation in copper by hydrogen H+ of 95 keV energy, only. The defects production has been identified in the region of about 400-800 nm. Results obtained by Monte Carlo calculations will be used for understanding of the experimental data from positron annihilation spectroscopy measurements which are scheduled for next year.
10.1016-j.commatsci.2005.05.004	-1		An earlier developed thermodynamic-kinetic solidification model for binary copper alloys is extended to take into account the formation of the bcc phase via the peritectic transformation and the formation of binary compounds from the fcc phase. Also the eutectic and eutectoid transformations are simulated but only approximately, by modeling the movement of the fcc/eutectic and fcc/ eutectoid interfaces due to the diffusion kinetics of the fee phase only. The new model can handle binary copper alloys containing solutes Ag, Al, Cr, Fe, Mg, Mn, Ni, P, Si, Sn, Te, Ti, Zn and Zr. Depending on the alloy composition, cooling rate and dendrite arm spacing, the model determines the fractions and compositions of the phases (liquid, fcc. bcc. compounds) and calculates thermo-physical material properties (enthalpy, specific heat, thermal conductivity, density and liquid viscosity). needed in heat transfer models, from the liquid state down to room temperature. The model is applied to Cu-Sn and Cu-Zn alloys but also to some other binary alloys to show the effect of cooling on the phases formed. Depending on the alloy system, the solidification structures obtained after real cooling processes are shown to be quite different from those estimated from phase diagrams.
10.1016-j.commatsci.2006.04.013	-1		A multi-objective optimization methodology for the aging process parameters is proposed which simultaneously considers the mechanical performance and the electrical conductivity. An optimal model of the aging processes for Cu-Cr-Zr-Mg is constructed using artificial neural networks and genetic algorithms. A supervised artificial neural network (ANN) to model the non-linear relationship between parameters of aging treatment and hardness and conductivity properties is considered for a Cu-Cr-Zr-Mg lead frame alloy. Based on the successfully trained ANN model, a genetic algorithm is adopted as the optimization scheme to optimize the input parameters. The result indicates that an artificial neural network combined with a genetic algorithm is effective for the multi-objective optimization of the aging process parameters.
10.1016-j.commatsci.2006.11.011	13	clusters; atomic; glass; atoms; composition; dynamics; metallic; icosahedral; glasses; simulations; molecular; cu-zr; molecular dynamics; metallic glasses; structural	This study presents a molecular dynamics simulation to investigate the pressure effect on the rapid and slow solidification of Cu in liquid state within Sutton-Chen type of the embedded atom method (EAM) potential. To determine temperatures of glass and crystal formation for the model system, radial distribution function (RDF), the changes of volume and Wendt-Abraham parameters are calculated for different pressures. Crystal and amorphous transitions for different pressures are formed at cooling rate of 4 x 10(12) K/s and 4 x 10(13) K/s, respectively. It is observed that the increase of pressure causes an increase of glass and crystal formation temperatures. Moreover, the local structures of the system are analysed by bond orientational order parameters to distinguish the simple structures in the system. It is observed that a higher pressure leads to a strong crystallization for lower cooling rate, but the glassy Cu forming for higher cooling rate at the same pressure have decreased icosahedral order, enhanced others clusters.
10.1016-j.commatsci.2008.01.007	-1		Elasto-plastic finite element analysis was carried out for analyzing the severe plastic deformation behavior of copper specimens during groove pressing. Deformation localization was studied in terms of strain variations along the longitudinal direction. Plastic strain is lower at the local interface between the shear and the flat regions, which receives very little shear during the pressing cycle. Strain localization is more intensified with the number of groove pressing cycles, although the average strain level increases.
10.1016-j.commatsci.2008.01.064	-1		Molecular-dynamics simulations have been used to study the local structure evolution and the glass formation in the Cu40Ag60 Melts rapidly cooled under high pressures. With the increase of pressures, the glass forming ability of alloy is improved. Our simulation results reveal that more compacted local structure with more ideal icosahedra than defected icosahedra is obtained. Both the annihilation of the free volume of the system and the increase of the number of the ideal icosahedra under high pressures contribute to the glass formation of the Cu40Ag60 alloy.
10.1016-j.commatsci.2008.03.037	0	solidification; phase; magnetic; magnetic field; undercooling; field; liquid; separation; peritectic; immiscible; cu-; dendrite; phase separation; microstructure; primary	A model is presented to describe the microstructure evolution during a liquid-liquid decomposition when cooling an alloy rapidly in the miscibility gap. The model was first verified by comparing with the experiments and then applied to investigate the microstructure formation in a rapid solidified Cu-Co alloy. The results indicate that the size of the minority phase particles is dominated by the nucleation behavior of the minority phase droplets (MPDs) during the liquid-liquid decomposition. Both the Brownian coagulations of the MPDs and the diffusional interaction between the MPDs affect the nucleation of the MPDs. The later has a relatively stronger effect.
10.1016-j.commatsci.2008.08.021	-1		A new interatomic potential for copper-antimony (Cu-Sb) in low Sb concentration solid-solution alloys is proposed based upon the Lermard-Jones (LJ) pair formulation. Parameters for this new potential, sigma and epsilon, are motivated by calculations of the Cu-Sb heat of solution (heat of mixing) and the strain field generated by a single substitutional impurity in single crystal copper, which is analyzed for impurity (dopant) atoms with various atomic radii. A well established embedded-atom method (EAM) potential is used to model the host copper. The epsilon parameter is derived for a range of values of sigma by matching to the experimental value of the heat of solution. Then, the strain field around a single dopant atom is computed for each set of the calculated LJ parameters. Ultimately, the final parameters for the Cu-Sb interaction are selected to match the strain field corresponding to the atomic radius mismatch between Sb and Cu and are compared with the Eshelby solutions which are based on classical theory of elasticity. As an application of this new potential, it is shown using molecular dynamics simulations that the plastic deformation behavior of single crystal copper is affected by the characteristics of the strain field around the dopant atoms.
10.1016-j.commatsci.2010.01.015	-1		An overview of a recent series of ab initio molecular dynamics (AIMD) simulations for the liquid, undercooled states of materials forming metallic glasses is presented. Here we use a combination of state-of-the-art computational techniques to resolve the atomic-level structure of such disordered systems. The dynamic properties, such as the self-diffusion coefficients and viscosity, are also studied as a function of temperature in the undercooled regime. By analyzing two model systems that involve different chemistry, i.e. Cu-Zr and Au-Si systems, we identify the local icosahedral ordering as a fundamental process underlying structural relaxation. Our findings have also strong implications for understanding the nature of the glass forming ability and properties of metallic glasses.
10.1016-j.commatsci.2011.04.014	-1		We present results on the bonding nature of doped CuxZr12-xY Icosahedra (Y = Mg, Be, Al, Si, P, Nb, Ag). We found that a p-electron type dopant, as central atom, results in the creation of a plane with free of core-shell atomic bonds, at certain energies and weak interactions at the Fermi level, which could be viewed as a slip plane. s or d-electron type dopants may behave similarly due to significant charge transfer towards unoccupied p-electrons occurring upon alloying. These results help in the elucidation of the micro-alloying effect found experimentally in many metallic glasses.
10.1016-j.commatsci.2012.08.027	-1		First-principles calculations are performed to investigate the structural properties and phase stability of (Cu, Zn)(6)Sn-5 and Cu-6(Sn, Zn)(5). Among these ternary intermetallic compounds (IMCs), Cu6ZnSn4 with Sn-3(4e) site substituted by Zn is the most stable. With the increase of Zn content, the heat of formation (Hf) of (Cu, Zn)(6)Sn-5 structures becomes higher. This work further explores the effects of different substitutional elements (Co, Ni, Ag, Au and Zn) on the H-f of (Cu, M)(6)Sn-5 (M is the alloying element) structures. The stability of these structures is closely relevant to the bonding energy of M-Sn and M-Cu bonds.
10.1016-j.commatsci.2013.04.057	-1		The structural, electronic and lattice-dynamical properties of Cu and Ag at different electronic temperatures have been investigated via density functional calculations. The results of electronic density of state indicate that both of Cu and Ag are still metals after intense laser irradiation. The smaller width of the DOS for Cu and Ag induce a motion towards higher energies when electronic temperature is elevated. The calculated phonon frequencies of Cu and Ag at high-symmetry points of the Brillouin zone (BZ) at T-e = 0 eV show a good agreement with the experimental values and other calculations. When Cu and Ag undergo a sharp increase of its electronic temperature, the phonon frequencies of Cu and Ag experiment a significant hardening. The predicted melting temperatures of Cu and Ag undergo a sharp increase after intense laser irradiation. We interpret this as the clear signature of the stabilizing effect of intense laser irradiation on the Cu and Ag lattices, which in turn may result in a significant time delay for the lattice to melt.
10.1016-j.commatsci.2013.04.067	13	clusters; atomic; glass; atoms; composition; dynamics; metallic; icosahedral; glasses; simulations; molecular; cu-zr; molecular dynamics; metallic glasses; structural	Structural and electronic properties of main YCu2 and YZn2 binary compounds with C14, C15, C36 Laves phases and CeCu2 structure in Cu-Y-Zn alloy are investigated by first-principles calculations. The related total energies versus occupations of nonequivalent lattice sites in all four structural forms were studied. Density functional theory is considered within framework of both pseudo-potentials and plane waves basis using VASP (Vienna ab initio Software Package). The optimized structural parameters were in very good agreement with the experimental values. Formation heat has been computed and showed that the CeCu2-YCu2 and YZn2 Laves phases have the strongest alloying ability and structural stability. Electronic density of states (DOSs) and charge density distribution were calculated and discussed in terms of structure stability.
10.1016-j.commatsci.2013.08.057	7	irradiation; shear; grain; ta; deformation; size; radiation; voids; nanocrystalline; simulations; similar; void; temperature; irradiated; boundaries	Virtual nano-tensile tests using Molecular Dynamics (MD) simulations are performed in order to predict the change in mechanical strength of Cu-alloyed alpha-Fe with thermal ageing. A novel sequential multiscale approach is adopted to simulate the microstructure evolution during ageing. In this approach, kinetic Monte-Carlo simulations are used to capture nucleation, growth and early stages of Cu particle coarsening whereas phase-field simulations capture further particle coarsening yielding particle mean radii of above 3 nm in feasible computation times. The MD results show the correctness of this multiscale approach by predicting a continuous trend in structure-property correlation. The yield strengths of the samples are found to decrease with ongoing thermal ageing due to the lack of a priori existing dislocations in the material and the enhanced dislocation nucleation at Fe-Cu interfaces.
10.1016-j.commatsci.2013.12.058	13	clusters; atomic; glass; atoms; composition; dynamics; metallic; icosahedral; glasses; simulations; molecular; cu-zr; molecular dynamics; metallic glasses; structural	We have performed molecular dynamics simulations to study the evolution of local atomic structure of the Cu50Zr50 metallic glass during glass formation. It was found that the coordination number of the Cu atoms mainly distribute from 10 to 12, whilst that of the Zr atoms ranges from 13 to 15. The structural analysis showed that the icosahedral-like and Frank-Kasper polyhedra are dominant in both the under-cooled liquid and the glass, and Cu5Zr7 and Zr8Cu7 polyhedra are the major local structural units for the Cu- and Zr-centered clusters, respectively. Moreover, three typical medium-range orders constructed by icosahedral-like, Frank-Kasper, and Bernal polyhedra via the linkage of vertex-, edge-, face-, and inter-crossed-shared atoms have been revealed in the metallic glass. The peculiar local structures and the connected complex medium-range ordering might be responsible for the high glass forming ability of the binary alloy due to their chemical and structural incompatibility with the primary competing crystalline phase.
10.1016-j.commatsci.2014.03.053	13	clusters; atomic; glass; atoms; composition; dynamics; metallic; icosahedral; glasses; simulations; molecular; cu-zr; molecular dynamics; metallic glasses; structural	Structural and mechanical properties of main YCu2 and YZn2 binary compounds with C14, C15 Laves phases and CeCu2 structure in Cu-Y-Zn alloy are investigated by first-principles calculations. The related total energies versus occupations of nonequivalent lattice sites in all four structural forms were studied. Density functional theory is considered within framework of both pseudo-potentials and plane waves basis using VASP (Vienna ab initio Software Package). Formation heat has been computed and showed that the CeCu2-YCu2 and YZn2 Laves phases have the strongest alloying ability and structural stability. Mechanical properties were calculated, discussed, and analyzed with data mining approach in terms of structure stability.
10.1016-j.commatsci.2014.08.033	-1		We present a study of the short-and long-range ordering phenomena that take place in the bcc beta phase of the ternary alloy Cu-Zn-Al. The results have been obtained by means of Monte Carlo simulations based on a three states Ising Hamiltonian. The evolution of the long-and short-range order degrees, internal energy, entropy and Helmholtz free energy are calculated as functions of temperature. The impact of short range order on the thermodynamics of the system is evaluated. The results obtained with the Monte Carlo technique are contrasted with those obtained within two different analytical approximations, whose validity is discussed. The calculated thermal variation of the specific heat near the long range ordering transitions is discussed and compared with experimental data.
10.1016-j.commatsci.2014.10.031	13	clusters; atomic; glass; atoms; composition; dynamics; metallic; icosahedral; glasses; simulations; molecular; cu-zr; molecular dynamics; metallic glasses; structural	To investigate the formation and evolution mechanisms of nano-clusters formed during the rapid solidification process, a molecular dynamics (MD) simulation study has been performed for a system consisting of 106 atoms of Cu64.5Zr35.5 alloy. Adopting a new cluster-type index method (CTIM-3) to analyse the local atomic clusters, it is found that the dominant microstructural configurations in the supercooled liquid and amorphous are the icosahedrons and their combinations, especially the intercross-sharing (IS) clusters linked of two icosahedrons (IS-ICO-clusters) can be used to build some larger IS-ICO nano-clusters with different sizes. Highly interesting, in the system the number of atoms in various IS-ICO nano-clusters demonstrates a magic number sequence of 19, 23, 25, 27, 29, 31, 33, 35, 37, 41, 43, and so on. The magic number clusters can be classified into three main types: chain-like, triangle-tailed and quadrilateral-tailed. The degree of tightness for IS-ICO nano-cluster can be expressed by formula n(I)/n(IS). And some IS-ICO nano-structures have stronger mechanical stability and can bear higher load. (C) 2014 Published by Elsevier B.V.
10.1016-j.commatsci.2015.03.041	-1		In this work we demonstrate, by means of molecular dynamic simulations, that the topological instability caused by successive substitutions of Zr in the Cu lattice, or Cu in the Zr lattice towards a final alloy composition of Cu65Zr35, transform the initial systems to the same amorphous structure at 300 K. Such a structure, however, is composed of less ordered clusters, i.e. less icosahedral-like clusters in comparison with the same amorphous alloy produced by rapid quenching from the melt. After a short time annealing at 800 K the less ordered structure evolves towards the structure of the rapidly solidified sample. From these results it comes out that no structural differences are to be expected in metallic glasses produced by mechanical alloying and by rapid quenching; any differences found in metallic glasses produced by these two different routes should be attributed to insufficient alloying treatment during the mechanical alloying procedure.
10.1016-j.commatsci.2015.04.039	7	irradiation; shear; grain; ta; deformation; size; radiation; voids; nanocrystalline; simulations; similar; void; temperature; irradiated; boundaries	An interatomic potential for the Cu-Al system based on the modified analytic embedded-atom method was proposed, which provides a reasonable description of the phase stability across the phase diagram. Combining with this potential, Monte Carlo simulations were performed to study strain-induced element segregation and intermixing in bulk and nanostructured Cu95Al5 and Cu90Al10 alloys. Al with a large atomic size is found to segregate to the tensile region while Cu to the compressive region. The elemental depletion or enrichment in dilute or nanostructured alloy is more notable than that in concentrated or bulk one, due to alloy effects or change of local stress. In particular, phase separation in nanostructured alloys leads to a single pure Cu inclusion in the matrix, which will induce strain hardening. The element segregation also affects the chemical ordering that will provide solid-solution strengthening.
10.1016-j.commatsci.2015.07.030	-1		This research investigates thermal conductivity properties of Cu/Zr alloys combined with diamond particles to form a composite that possess superior thermal conductivity. This article describes the use of a theoretical calculation and finite element analysis to compare to previously published experimental observations. Both theoretical calculations and finite element analysis indicate that experimental results cannot be explained solely by an improved interface between the matrix and diamond particles, as originally suggested. This study shows that the experimental results, theoretical calculations, and finite element analysis are in agreement when the thermal conductivity of the matrix is adjusted to compensate for the amount of zirconium lost to the interface. This finding can be used to predict the thermal conductivity of a composite material composed of a Cu/Zr matrix with diamond particles.
10.1016-j.commatsci.2015.12.005	-1		In this study, we investigate the mechanical responses of copper based alloy, NARloy-Z, under cyclic loadings at different strain rates and strain amplitudes, and also creep at different levels of stresses. We examine the effect of temperature changes, as a result of energy dissipation during loading, on the overall cyclic and creep responses of NARloy-Z. A phenomenological viscoplastic model, developed by Freed et al (1994), is adopted and modified in order to incorporate the effect of energy dissipation on the viscoplastic response of NARloy-Z. An adiabatic process is assumed to convert the dissipated energy into temperature increase, and the resulting temperature changes alter the elastic modulus and plastic flow of NARloy-Z during loading. A numerical method is also presented in order to implement the above nonlinear constitutive model. Experimental data reported by Conway et al (1975) for cyclic loading and Ellis and Michal (1996) for creep loading are used to examine the viscoplastic responses of NARloy-Z. From the analyses, it is concluded that the amount of energy dissipation is much more pronounced under cyclic loading, especially for long-term duration of cyclic loading, while it is negligible under creep loading. Higher strain rates result in higher energy dissipation, which is expected as higher strain rates accumulate more hysteretic cycles at the same loading duration. Large amount of energy dissipation leads to a pronounced stress softening behavior due to significant increases in temperatures. The stress softening is one of the sources for material failures. It is also seen that the energy dissipation, and its corresponding temperature increase, is an important component in determining fatigue failure of NARloy-Z.
10.1016-j.commatsci.2016.08.031	-1		Molecular dynamics simulations based on an embedded-atom-method potential were performed to examine the structural and dynamical properties of the solid-liquid interfaces in the Cu-Ni alloy system with different orientations of the solid, i.e. (1 0 0), (1 1 0) and (1 1 1). The profiles of local order parameter, atomic number density, diffusion coefficients and Lindemann indices were evaluated and the interface widths were determined based on them. The widths are found to depend on the orientation of the underlying solid, while the orientation dependence for widths based on different criteria differs. The ones based on the local order parameter, given as the difference between an actual local atomic configuration and a referential ideal crystalline one, are found to be able to reflect the transitions across the interface in terms of both geometry and atomic motility, and are therefore most reliable. The interfacial layers are found to be composed of mixtures of both solid and liquid phases, the tempo-spatial variations of their relative amounts play an important role in determining the interfacial properties, including the interfacial widths. These findings can lend support to model the behavior of the solid-liquid interfaces at coarse grained scales, such as phase field modelling of dendrite growths.
10.1016-j.commatsci.2016.11.029	-1		Long range ordering in the bcc phase of the Cu-Al-Ni alloy is modelled through the analytical Bragg-Williams approximation and by means of numerical Monte Carlo simulations. The interchange energies that govern the ordering reactions are determined by fits to experimental ordering temperatures. A satisfactory agreement with the experimental data is obtained within both models, using slightly different sets of interchange energies. It is found that ordering in first neighbours is driven by the Ni-Al interactions, whereas the ordering in next nearest neighbours occurs by a reordering of Cu-Al pairs. Monte Carlo simulations enable a reinterpretation of the experimentally observed ordering reactions. Further details of the ordering process, such as the existence of tricritical points as the Ni content is reduced, and the evolution of sublattice occupancies as the ordering proceeds are also discussed: the site occupation probabilities at low temperatures agree with the experimental values.
10.1016-j.commatsci.2016.11.045	13	clusters; atomic; glass; atoms; composition; dynamics; metallic; icosahedral; glasses; simulations; molecular; cu-zr; molecular dynamics; metallic glasses; structural	The lattice constant, formation enthalpy, and elastic parameters of Cu1-xAux (0 <= x <= 1) alloys in the face centered cubic crystallographic phase are investigated by using the first-principles exact muffin-tin orbitals and plane-wave pseudopotential methods in order to explore the effect of alloying with special focus on the impact of local lattice distortion (LLD) on the above properties. The compositional disorder is treated within the framework of the coherent potential approximation (CPA) and the special quasi-random structure (SQS) scheme. Calculations based on SQS and CPA show that, while LLD lowers significantly the formation enthalpy of Cu1-xAux due to the large size mismatch between Cu and Au atoms, it has negligible influence on the lattice constants and elastic parameters. These findings confirm the reliability of CPA for computing the enthalpy changes upon isotropic and unisotropic lattice distortions in disordered alloys with sizable atomic size differences.
10.1016-j.commatsci.2016.12.003	7	irradiation; shear; grain; ta; deformation; size; radiation; voids; nanocrystalline; simulations; similar; void; temperature; irradiated; boundaries	The plastic deformation behaviours of Cu50Zr50/Cu amorphous/crystalline nanolaminate were studied at the atomic scale using molecular dynamics simulations. Unlike the limited plasticity due to the highly localized shear banding in pure metallic glass, the nanolaminate undergoes a pronounced homogeneous deformation under applied tensile strains greater than 8.0% that is 36.4% larger than that of pure metallic glass. This plasticity enhancement is attributed mainly to the suppression of the nucleation and propagation of the shear band in the nanolaminate. The scattered immature shear band or shear transformation zones and dislocations cooperate to form a network to transmit the strain within the entire sample. Significant size effects are demonstrated, revealing that both the strength and elongation-to-failure reach their respective peak values at a layer thickness d of approximately 4 nm and that the relationship between strength and d is well-explained by the confined layer slip (CLS) model. In the case of d values from 27 nm to 4 nm, the nanolaminate undergoes a transition from inhomogeneous deformation to homogeneous deformation. When d decreases to less than 4 nm, the nanolaminate exhibits inhomogeneous deformation because of the destruction of the amorphous/crystalline interface. On the basis of this mechanical mechanism, the present study provides an approach for strengthening and toughening the amorphous/crystalline nanolaminate by adjusting the layer thickness.
10.1016-j.commatsci.2017.01.021	-1		A novel mechanism without involvement of vacancy or Frank loop is put forward to cast light on the formation of stacking fault tetrahedron (SFT) during plastic deformation of bulk single-crystal Cu with preexisting parallel coherent twin boundaries (CTBs) via large scale molecular dynamics (MD) simulation. The fresh mechanism is totally different with Silcox-Hirsch mechanism and its sequelae, which supports that to produce an SFT during plastic deformation, formation of Frank loop is not essential in metals with low stacking fault energy (SFE).
10.1016-j.commatsci.2018.07.049	-1		The mechanical properties of powder metallurgy (PM) materials are closely related to their density. In this case we demonstrate an approach of utilizing machine-learning algorithms trained on experimental data to predict the sintered density of PM materials. Descriptors were selected from the features including processing parameters, chemical composition, property of raw materials and so on. And the training data are collected by the experimental setup in our lab and the literatures on five kinds of P/M alloys. The multilayer perceptron model (MLP) outperformed other four regression and neutral network models with high coefficient of correlation and low error. The sintered density predicted by MLP model agreed well with the experimental data with a tolerable error less than 0.028, which confirms its capability over P/M materials design procedures. Then the obtained MLP model is used for Cu-9Al P/M alloy to guide selecting the processing parameters to reach the expected sintered density of 0.88. The Cu-9Al powders were fabricated with the predicted parameters including the specific shape factor, particle size, pressing pressure and sintering temperature, and the obtained relative sintered density is 0.885.
10.1016-j.commatsci.2018.07.050	13	clusters; atomic; glass; atoms; composition; dynamics; metallic; icosahedral; glasses; simulations; molecular; cu-zr; molecular dynamics; metallic glasses; structural	The solid-liquid portion of the equilibrium phase diagram at the Cu rich side of a Finnis-Sinclair description of Cu-Zr was determined by a combination of molecular dynamics and semi-grand canonical Monte Carlo simulations and the model system was found to be in very good agreement with experiment. Molecular dynamics simulations and the capillary fluctuation method were used to compute the solid-liquid interfacial free energy, gamma, and its anisotropy as a function of undercooling. Unlike the case of pure metals and in contrast to most previous atomistic studies in alloy systems, gamma was found to increase with decreasing temperature and the increase is quite pronounced. To verify the unusual results, the excess energy and number of Zr atoms were computed for the [1 0 0] interface and from the excess thermodynamic quantities gamma was obtained through a thermodynamic integration. The results of the two approaches for computing gamma are in agreement to within the statistical uncertainties. The implications of the temperature behavior of gamma is discussed in terms of crystal nucleation from the melt and glass formation.
10.1016-j.commatsci.2019.109154	-1		DFT calculations (typically done at 0 K), Helmholtz free energy and Gibbs free energy calculations (for high temperature) within the quasi-harmonic approximation have been done in this manuscript to probe a metastable phase of Cu observed at high temperature and high pressure. The high electronic thermal conductivity observed for this new metastable phase of Cu may be beneficial for high temperature engineering applications in electronic and spacecraft device designs.
10.1016-j.commatsci.2019.109162	-1		Molecular dynamics simulations are employed to study mechanistic characteristics of Cu-Zr metallic glasses films during the imprinting process. The influences of punch geometry, loading velocity, temperature, and alloy composition are exhaustively analyzed in terms of imprinting force, deformation characteristic, residual stress, displacement vector, radial distribution function, and elastic recovery ratio. The results show that the imprinting force and the shear transformation zones (STZs) of the Cu50Zr50 MGs films increase, while the residual stress has slightly changed with increasing angle of the punch . In the case of different imprinting velocities, the imprinting force increases. The residual stress also increases in the loading stage; however, it decreases in the unloading stage. The imprinting force, residual stress, highest peak of the radial distribution function (RDF) decrease and movement of atoms become irregular as increasing of temperature. As increasing Cu proportion, the imprinting force increases, the density of atom movement and residual stress increases, while the highest peak of the RDF decreases. The formality of the Cu-Zr MGs films can be improved by increasing Cu proportion and loading velocity, decreasing temperature due to lower average elastic recovery ratio. The imprinting force values are in the range of 100-185 nN, the residual stress values of the loading stage are from 0.44 to 0.82 GPa and the residual stress values of the unloading stage are from 0.4 to 0.9 GPa, the elastic recovery ratio are in the range of 0.17-20.26%.
10.1016-j.commatsci.2019.109353	-1		In present work, the glass-forming ability of Cu-Zr and Cu-Al systems has been estimated by utilizing a monolayer two-dimensional model. The structure of 2D Cu-Zr MGs can be simply characterized by three kinds of Voronoi polygons, i.e. pentagon, hexagon and heptagon, and the structural translational symmetry is broken down by the strong coupling effect between pentagon and heptagon, promoting the formation of MGs. Moreover, the larger bond lengths of Cu-Zr and Zr-Zr pairs are found responsible for the outstanding GFA of Cu-Zr system. The 2D model provides a promising avenue for accurately predicting the GFA of alloys of interest, which is important both in theoretical research and engineering.
10.1016-j.commatsci.2019.109454	13	clusters; atomic; glass; atoms; composition; dynamics; metallic; icosahedral; glasses; simulations; molecular; cu-zr; molecular dynamics; metallic glasses; structural	Applying the Naval Research Lab tight-binding method, we have developed parameter sets for the Cu-Ag noble metal binary system. The tight-binding Hamiltonians are determined from a fit that has a non-orthogonal basis and reproduces the electronic structure and total energy values of first-principles linearized augmented plane wave calculations. The parameters were fit to the structures B-2, L-10, L-12 ( X3Y and Y3X) with the X and Y representing the different combinations of the Cu and Ag in addition to the fcc Cu and Ag. The method reproduced the first-principles ordering of these structures and found the ground-state structure of the system to be the L1(2) (Cu3Ag). As an output of this approach, the following quantities were reproduced in good agreement with available experimental and theoretical values: elastic constants, densities of electronic states as well as the total energies of additional crystal structures that were not included in the original first-principles database. We used this TB parametrization to successfully perform molecular dynamics simulations and determined the energies for vacancy formation. Temperature dependence of the coefficient of thermal expansion, the mean squared displacement and phonon spectra for the system were also calculated. In addition we show that these TB parameters work for determining binding energies and bond lengths of Cu-Ag fcc-like clusters.
10.1016-j.commatsci.2020.109547	7	irradiation; shear; grain; ta; deformation; size; radiation; voids; nanocrystalline; simulations; similar; void; temperature; irradiated; boundaries	The formation of twins in face-centered cubic (FCC) crystals is influenced by both the energy barriers and associated shear directions. In this study, we formulate and implement a theoretical framework to study 15 pure FCC metals in an effort to propose a twinning propensity descriptor to predict the tendency for twin formation in FCC metals under different shear directions. Our calculations demonstrate that deformation twins form readily in: Al, Ir, Ni, Rh, Co, Au, Cu, Yb, Ag, Sr, and Ca, but have difficulty forming in: Ce, Pt, Pb, and Pd, and this trend is consistent with available experiment results. Using this descriptor, we further predict that in the case of Cu-Al alloys the highest twinning propensity is achieved at similar to 6 at% Al concentration, which is also consistent with experimental observations. These results provide insight into the nature of deformation twins, and furthermore help establish the framework necessary to design FCC metals and alloys with a high tendency for twin formation.
10.1016-j.commatsci.2021.110842	-1		The morphology of the second phases formed during the solidification is irregular in many alloy systems, making precise simulation of their dissolved evolution difficult. In this work, a multi-particle spherical log-normal distribution was used to simulate the dissolution of such irregular second phase and took the as-cast Cu-Ti alloy as a case study. The dissolution of the as-cast Cu4Ti phase was simulated via a multi-particle dissolution model integrating the CALPHAD-based diffusion theory (CALPHAD: CALculation of PHAse Diagrams) and high-throughput calculations. The 5041 sub-models (spherical log-normal distributions) replacing the size distribution of the as-cast Cu4Ti phase were initially generated based on the mass balance. Then, 2.5 x 10(6) data points in 491 sub-models selected from 5041 sub-models were calculated to fit the experimental DSC curves based on the energy conservation, and the best-fitted sub-model could be determined finally. Based on this sub-model, the volumetric and energetic evolution of the as-cast Cu4Ti phase during various dissolution processes could be predicted, and the simulated results were confirmed to be in agreement with the present experimental results. Also, a counterintuitive self-coarsening phenomenon of the Cu4Ti phase has been observed during heating, which has been approved in the experimental work.
10.1016-j.commatsci.2021.110885	-1		Shear stress relaxation through the motion of multiple edge dislocations in a periodic cell is studied by molecular dynamics and discrete dislocation methods. In both methods, we consider systems with an initial edge dislocation on the parallel slip planes. The initial shear strain is applied to the system along the Burgers vector of the dislocations. The velocity profile for a single edge dislocation fitted from a molecular dynamics (Bryukhanov, 2020) is used as the input to discrete dislocation dynamics. The dependence of shear stress, plastic strain, and plastic strain rate on time are analyzed. We show that when dislocations are sufficiently far from each other, relaxation occurs due to dislocation motion, and dislocation velocity can exceed the anisotropic speed of sound. If the dislocations are closer together, relaxation is due to the growth of stacking faults. We find that the stress at which the stress relaxation mechanism changes decreases with increasing dislocation density. Stress relaxation in a Cu-Ni solid solution occurs faster than in pure Cu due to a higher dislocation velocity in the high-velocity regime. However, the shear stress at which nickel atoms increase the plastic strain rate increases with an increase in dislocation density. The dependence of the relaxation time on the dislocation density obtained in discrete dislocation simulations is approximated using the power law. The elastic interaction between dislocations reduces the exponent of the power law from 1/rho to approximately 1/rho(0.8) for both pure Cu and Cu-Ni solid solutions.
10.1016-j.commatsci.2021.111087	-1		In general, with the addition of solutes, the yield strength of alloys is expected to increase; this phenomenon is known as solid solution strengthening. However, this model of strengthening implicitly assumes that dislo-cations are available and it is their motion that causes plastic deformation. On the other hand, in dislocation starved regimes, it is the nucleation of dislocations that controls the deformation behaviour. In this regime, the solute atoms can act as sites of heterogeneous nucleation for dislocations and anomaloussoftening with alloying additions are not uncommon. In this study, using Molecular Dynamics (MD) simulations, we show anomalous softening in Cu-Al alloys deformed at 300 K. We show that there are two components to this softening; in addition to the heterogeneous nucleation at solute sites, the reduction in stacking fault energy with alloying addition promotes the (homogeneous) nucleation of partial dislocation loops. In order to be consistent, we interpret the MD simulation results of deformation behaviour using parameters and energies derived from the same potentials used in the simulations. Specifically, we carry out the thermodynamic integration to evaluate the free energies in crystals with and without the stacking faults and hence calculate the SFE as a function of Al content at 300 K. Using the SFE values thus obtained, and using a continuum model of homogeneous nucleation of partial dislocation loops, we rationalise the deformation behaviour seen in pure copper. On the other hand, in Cu-Al alloys, the drop in yield strength can only be explained using a combination of the continuum model (which assumes homogeneous nucleation), and the reduction in heterogeneous nucleation barrier (which is a function of the ratio of the unstable and stable stacking fault energies). Thus, our results indicate that deformation experiments of pure copper and copper-aluminium alloys in the dislocation starved regime could be interesting and might show qualitatively and quantitatively different behaviour.
10.1016-j.commatsci.2022.111971	-1		The generalized stacking fault energy profile is fundamental to models of metal plasticity and thus a key parameter for alloy design. However, to account for thermal vibrations, models require the stacking fault free energy profile, but current methods can only calculate metastable intrinsic stacking faults. We show how the full stacking fault free energy profile can be calculated using PAFI, a linear scaling method that fully accounts for anharmonic thermal vibrations. Applying our approach to empirical and machine learning potentials for FCC Cu, we show via direct comparison with molecular dynamics simulations that accounting for temperature effects is essential to predict the statistics of partial dislocation separations. The machine learning potential gives quan-titative agreement with available density functional theory data on the intrinsic stacking fault energy, whilst additionally returning the unstable stacking fault, a key parameter for predicting ductile fracture.
10.1016-j.commatsci.2023.112104	-1		The paper deals with the role of Al in thin film metallic glasses based on Cu and Zr. We employ a combination of molecular-dynamics simulations of the atom-by-atom growth process with magnetron sputtering. We use the previously studied composition Cu0.46Zr0.54 as a starting point, and focus on the effect of Al incorporation into Cu0.46Zr0.54 (simulations) and Cu0.46(Zr + Hf)0.54 (sputtering). We go beyond the state-of-the-art by quantifying the homogeneity, densification, short-range order (bonding preferences and coordination numbers), mediumrange order (common neighbor and network ring statistics) and functional properties (hardness, Young's modulus, glass transition temperature and crystallization temperature) in a wide range of Al contents (0 to 20 at. %) and growth conditions. We identify the key building blocks of Cu-Zr-Al: icosahedral clusters (12 vertices) centered around Cu and Al, and supraicosahedral clusters (16 vertices) centered around Zr. The atomic-scale simulations provide a lot of information not accessible experimentally and explain the experimental data. The results are important for understanding the structures and properties of this class of metallic glasses, and for optimizing their compositions and pathways for their preparation for various technological applications.
10.1016-j.commatsci.2023.112284	13	clusters; atomic; glass; atoms; composition; dynamics; metallic; icosahedral; glasses; simulations; molecular; cu-zr; molecular dynamics; metallic glasses; structural	We present a new classical interatomic potential for molecular dynamics simulations of copper. The potential was developed within the N-body approach, which, in addition to pair and many-body interactions, can take into account three-body ones with the required precision. Our potential accurately predicts a wide range of properties of copper: structural, elastic, point and planar, and thermal such as melting point. The latter is essential for the proper reproduction of the homologous temperature and comparison of the calculated results with the corresponding experimental data, such as diffusion coefficients. The potential predicts the intrinsic stacking fault energy within the range of experimental measurements, which indicates its ability to correctly describe the deformation behavior of copper. In this work, we performed simulations of lattice and grain -boundary diffusion of copper with our potential. It shows a moderate overestimation of the lattice diffusivity with a deviation less than one order of magnitude. To simulate the grain boundary diffusion, we built a general-type grain boundary employing the original method. The calculated grain-boundary diffusivity is in remarkable agreement with the literature data and almost coincides with them at higher temperatures in the considered temperature range. The constructed potential can be effectively used for molecular dynamics simulations of defect properties and diffusion phenomena and composing the interatomic potentials within the N-body approach for alloys containing copper.
10.1016-j.commatsci.2023.112449	-1		To investigate the complex nonlinear relationship between the composition and properties of high-performance copper alloys, a double-layer artificial neural network model based on a genetic algorithm (ANN-GA) was developed using MATLAB tools. The dataset showed that the correlation coefficient of the model was greater than 95%. Quantitative calculation formulas for the alloy composition, ultimate tensile strength (UTS), and conductivity were established using the transfer function, weights, and thresholds of the ANN-GA model. The effects of the main elements on the mechanical and electrical properties of the alloys were analysed. The simulation results were similar to the experimental results obtained by the ANN-GA, confirming the excellent prediction ability of the model. Four advanced copper alloys with high strength and conductivity were successfully simulated to meet the targets of UTS (=540 MPa) and conductivity (=80% IACS). Two alloys were selected for melting, heat treatment, and performance testing. The error between the experimental results and predicted results was within 5%, demonstrating the applicability of the model. The proposed framework is useful for designing high-performance Cu alloys.
10.1016-j.commatsci.2023.112772	13	clusters; atomic; glass; atoms; composition; dynamics; metallic; icosahedral; glasses; simulations; molecular; cu-zr; molecular dynamics; metallic glasses; structural	Based on the first -principles cluster variation method (CVM), the atomic sizes of Cu and Au in a Cu -Au solid solution were estimated as a function of concentration. The atomic volumes of both Cu and Au atoms in their pure metals remain almost unchanged over the entire concentration range. The Bader analysis based on the electronic structure of a random solid solution gave the information of the atomic size, confirming the results of the first -principles CVM. The Bader analysis further revealed that Cu atoms in the random phase are classified into two types: the first type increases in volume upon alloying while the other type loses volume despite both types losing charge. Computer simulation of the local lattice relaxation satisfactorily yielded the relaxation energy which resolved the discrepancy of the Cu3Au (γ′) -disorder transition temperature between the firstprinciples CVM and experimental results.
10.1016-j.commatsci.2024.112827	5	materials; thermal; heat; properties; material; welding; sintering; fusion; strength; laser; heat sink; thermal conductivity; mechanical; sink; manufacturing	Powder metallurgy processed Cu-Sn alloys consolidated via liquid phase sintering (LPS) often contain significant amount of porosity which not only deteriorates their mechanical properties but also adversely affects their functional performance. During LPS, shrinkage and swelling are the two competing processes that in turn determine the extent of porosity and densification behaviour of the sintered alloy. However, there is no straightforward method for determining in advance, whether a specific powder compact would experience swelling or shrinkage after sintering. This paper describes how a classification-based machine learning (ML) framework could very well forecast sintering response of Cu-Sn alloys prior to the actual sintering process. Sintering behaviour of the compacts was modelled using densification parameter as the target variable. The characteristic features of powder, composition and processing parameters were used as input variables of the ML model. Prediction performance of 'Logistic Regression (LR)' and 'Support Vector Machine (SVM)' were found to be inferior as compared to 'Random Forest Classification (RFC)' model which emerged as most prospective with a classification accuracy of 0.92. Results obtained from the model indicate that green density, sintering temperature, compaction pressure and powder type are the most important factors affecting the volumetric change. The data driven ML modelling strategy adopted in this work can facilitate pre-selection of relevant processing parameters, thus reducing the risk of abnormal swelling of compact and accompanying pore coarsening encountered during liquid phase sintering.
10.1016-j.commatsci.2024.113450	-1		Cu-Sn alloy materials are widely used in electronic industry, aerospace and 3D printing. When studying the structure and properties of materials, a contradiction between arithmetic and accuracy is encountered by Molecular dynamics (MD). Molecular dynamics is a general theoretical calculation method for studying the mechanical properties of alloy materials. However, molecular dynamics simulations of alloy materials are limited to simple systems because the construction of traditional interatomic potentials is replicative and inefficient. In this study, the Cu-Sn material machine learning interatomic potential was constructed by using a deep neural network model, and the first-principles calculation results were used as the training data set to ensure the accuracy of the quantum mechanical interatomic potential. This process features an active learning process, data generation and model training methods with minimal human intervention. Molecular dynamics using machine learning interatomic potentials (MLIP) and first-principles calculations show good consistency. It was concluded that MLIP can accurately predict energy, force and mechanical properties. The root mean square error (RMSEs) of the energy and force per atom is approximately 10 meV/atom and 100 meV/& Aring;. It shows good advantages in energy-volume curve, phase transition temperature and elastic modulus, laying the foundation for the wide application of the MD method in the design and development of Cu-Sn alloy materials.
10.1016-j.commatsci.2024.113548	-1		The non-equilibrium atom-by-atom growth of Cu-rich Cu-Zr thin films has been investigated by a combination of magnetron sputter deposition and molecular dynamics simulations. We focus on the role of Zr in the transition from large solid solution crystals through a nanocomposite (around approximate to 5 at% Zr) to a metallic glass. We find, contrary to the assumption based on equilibrium phase diagram, that in this non-equilibrium case most of the grain refinement and most of the hardness enhancement (from 2.5 to 3 to 4-5 GPa) takes place in the compositional range (up to approximate to 3 at% Zr) where many or even most Zr atoms (depending on the sputtering regime) are in the supersaturated solid solution rather than at the grain boundaries. The results are important for the design and understanding of technologically important nanostructured metallic films. In parallel, from the methodology point of view, the results include an early example of modelling the atom-by-atom nanocomposite growth .
10.1016-j.commatsci.2025.113825	14	strength; properties; conductivity; electrical; mechanical; cu-; grain; mpa; electrical conductivity; aging; precipitation; phase; mechanical properties; tensile; phases	We develop a neural-network deep potential (DP) model spanning 0-3,000 K and 0-10 GPa, trained on density functional theory data across the full concentration CuxW100-x compounds. We systematically investigate the structural and mechanical properties of W-Cu alloys. The results show that the bulk modulus (B) and Young's modulus (E) of W-Cu alloys exhibit a linear decline as the Cu content increases, indicating a softening trend in the CuxW100-x compounds as the Cu concentration rises. Besides, a brittle-to-ductile transition in the deformation mode predicted is predicted at around 37.5 at. % Cu content. Moreover, tensile testing demonstrates that Cu-poor region effectively block shear band advancement, simultaneously stimulating nucleation of secondary shear bands in adjacent Cu-rich domains. The results are anticipated to aid in exploring the physical mechanisms underlying the complex phenomena of W-Cu systems.
10.1016-j.commatsci.2025.113886	7	irradiation; shear; grain; ta; deformation; size; radiation; voids; nanocrystalline; simulations; similar; void; temperature; irradiated; boundaries	Irradiation-induced creep in nanocrystalline Cu was simulated with the aim of analyzing the microscopic mechanism driving creep. The systems included various immiscible mixtures where the solute atom segregated at grain boundaries and led to grain size stabilization. The small grain size in the nanocrystals prevents the development of dislocation-based dynamics within the grains, and gives rise to alternative mechanisms that are based on grain-boundary plasticity. We show a correlation between observed creep rates and the climbing of dislocations at the grain boundaries. Due to the simple structure of Cu-based alloys, they can serve as model systems for investigating irradiation-induced creep. This establishes the basis for a mean-field model that can predict the creep compliance of a sample as a function of its structure and composition. The model reproduces recent experimental measurements.
10.1016-j.compositesa.2006.05.002	16	wear; composite; composites; powders; milling; particles; powder; wt; sliding; friction; hardness; matrix; mechanical; surface; properties	Metal matrix composites (MMC) of copper and ZrC powders were prepared by the powder metallurgy route. Powders of both materials were introduced in stainless steel jag and mechanically mixed in a planetary mill under a protective atmosphere of argon during time ranging from 4 to 30 h . A characterization study of resulting powders indicated that a steady state particle distribution is developed after 12 h of milling. For this reason only these powders were consolidated by hot uniaxial pressing under 90 MPa at 923 K for 2 h . Residual porosity of these compacts was eliminated by rolling at 1073 K. Resulting materials present fine grained microstructure, tensile strength of 653 MPa and electrical conductivity up to 52% IACS. A detailed microstructural analysis by scanning and transmission electron microscopy showed not only ZrC particles but also the presence of very fine particles of carbides and oxides. WDX and EDX spectra of these particles revealed a high content of Fe and Cr for the carbides and Cu in the case of oxides. (c) 2006 Published by Elsevier Ltd.
10.1016-j.compositesa.2010.07.004	-1		We report the development of a novel light-weight Al (520) alloy-based composite reinforced with particles of a Cu-based (Cu54Zr36Ti10) metallic glass by mechanical milling followed by induction heated sintering. The consolidation of the composite is performed at a temperature in the super-cooled liquid region of the metallic glass just above its glass-transition temperature (T-g). Metallic glasses are a promising alternative reinforcement material for metal-matrix composites capable of producing significant strengthening along with a friendly sintering behavior. The mechanical milling procedures were properly established to allow reduction of the size of the metallic glass particles and their uniform distribution in the matrix. Microstructural observation of the composite did not reveal any porosity. The interface between the glassy particles and the matrix remained free of such defects. The fully dense consolidated composite showed a drastic gain in specific yield strength under compression relative to the matrix alloy and appreciable plasticity at fracture.
10.1016-j.compositesa.2016.05.027	-1		Superaligned carbon nanotube (SACNT) reinforced copper matrix laminar composites have been fabricated by means of the traditional copper sulfate electroplating process. The mechanical properties and transport properties of the Cu/SACNT composites with different SACNT content have been studied systematically, and the experimental results show that the as-prepared composites possess a better comprehensive performance than pure copper. The simple rule of mixtures (ROM) has been used to estimate the potential maximum properties of the Cu/SACNT composites. The Cu/SACNT composite is considered to be a promising material for electronics and communications applications.
10.1016-j.compositesa.2018.10.022	-1		Copper matrix composites are widely used as strong conducting materials. Mechanical properties and failure behavior at high temperatures are investigated for carbon nanotubes/copper matrix nanolaminated composites with well-balanced strength and ductility in this work. Tensile strength of the composite decreased considerably as temperature increased because of matrix softening and Cu grain coarsening. Deformation mechanism is controlled by pipe diffusion mechanism at 573 K, while lattice diffusion at 773 K. The failure behavior is shown to transform from interfacial debonding of CNT-matrix to Cu matrix failure as the temperature increases. CNTs are pulled-out on fractured surfaces at both room and high temperature, but with different morphologies. Elemental analysis and microstructural observations indicated that the interface shear strength is between the matrix strength of 75 MPa at 773 K and 320 MPa at room temperature. The results shed light on designing advanced copper matrix composites for applications at high temperature.
10.1016-j.compositesa.2020.105891	10	composites; nanoparticles; strength; matrix; high; strengthening; particles; conductivity; composite; electrical; mpa; sintering; ods; grains; mechanical	In metal matrix composites, it is commonly a hard task to achieve synergistic strengthening and toughening effects between two-dimensional graphene and zero-dimensional nanoparticles (NPs) reinforcements due to their huge dimensional gap. Herein, we developed an in-situ solid-state reaction method to incorporate graphene nanosheets (GNSs) and WC1-x NPs into copper matrix. It was proved for the first time by thermodynamics and crystallography calculations that the unusual gamma-WC1-x phase can be generated from the solid reaction and maintain stable at room temperature. Thanks to the unique distribution types of WC1-x, i.e. intergranular or intragranular distribution while other parts anchored on the surface of the GNSs, Orowan strengthening and load transfer strengthening were simultaneously achieved in the composites. Meanwhile, the thermal conductivity was also measured to be equal to that of pure Cu, exhibiting a promising prospect in applications as advanced multifunctional structural materials.
10.1016-j.compositesa.2021.106664	-1		Stoichiometric TiC and Cu are naturally non-wetting thus hindering application of the TiC-reinforced phase in Cu-matrix composites. In this study, stoichiometric TiC was converted to sub-stoichiometric TiCx through ball milling. The TiCx reinforced the Cu matrix after electropulsing-assisted flash sintering. When the content of C atoms in TiCx is sufficiently low, TiCx can form a good metallurgical bond with the Cu matrix. The hardness of the pure Cu matrix increased from 124 HV to 280 HV, and the strength increased from 347 MPa to 580 MPa when reinforced by 10 wt% TiC0.(6) . The activity of Ti in TiC0.6 with a low carbon content is enhanced; thus, its dissolution in the Cu liquid melt is increased. The Ti atoms in liquid Cu facilitates interface bonding. The use of sub-stoichiometric TiCx to strengthen Cu-matrix composites is a promising strategy to expand the application of Cu-matrix composites.
10.1016-j.compositesa.2023.107611	-1		Dynamic deformations at extreme strain rates (>10(6)/s) are frequently encountered by metallic structural materials. According to continuum theory, increasing the modulus and thus speed of sound in metallic materials could lead to enhanced impact resistance, while such goals are difficult to achieve via conventional alloying methods. On the other hand, recent researches have revealed that carbon materials such as graphene have far larger in-plane speed of sound than metals and therefore are intrinsically impact resistant. In this work, graphene/ copper (Gr/Cu) nanolaminates were fabricated by incorporating graphene into copper matrix, and its ballistic performance at extreme strain rates (similar to 3 x 10(7) /s) was quantified via laser-induced projectile impact tests (LIPITs). The specific energy dissipation of Gr/Cu nanolaminates is found to be 54 % higher than Cu. Postmortem analysis revealed that graphene nanoinclusions could cause additional coordinative deformation in regions surrounding the perforation zone in Gr/Cu, leading to enhanced ballistic performance of Gr/Cu nanolaminates.
10.1016-j.compositesa.2025.109255	14	strength; properties; conductivity; electrical; mechanical; cu-; grain; mpa; electrical conductivity; aging; precipitation; phase; mechanical properties; tensile; phases	The innovative stepwise gradient laminated structure effectively combined the characteristics of gradient structures and laminated structures. This study aimed to optimize the strength-ductility synergy in Cu/Ti3SiC2/C composites through a design featuring a stepwise gradient grain laminated structure, Cu/C multi-level interfacial configuration, and optimized orientation, fabricated via powder metallurgy (PM) and cumulative stacking (CS) method. The meticulously designed composite exhibited a stepwise gradient grain size distribution across layers, and Boltzmann statistics and orientation models showed that the degree of orientation of Cu-plated flake graphite (GFs@Cu) exhibited interlayer differences. Through microstructural analysis combined with theoretical modelling, it was verified that the interface reaction between Cu and Ti3SiC2 was a double-edged sword. The insitu reaction product TiC caused a performance loss of 9.17 MPa, while the deintercalation and diffusion of Si significantly reduced the stacking fault energy (SFE) of Cu, forming a stacking fault (SF)/twin strengthening network. The strength and plasticity of the composites were optimally matched, mainly due to the synergistic effect of hetero-deformation-induced (HDI) strengthening induced by the gradient laminated structure and the multi-level interface design of Cu/C. Experiments and model calculations confirmed that this novel staircase-type gradient laminated structure design strategy provides a promising approach for the development of heterostructure materials with application potential.
10.1016-j.compositesb.2017.12.050	-1		Copper-graphite composite is an ideal friction material due to its good heat resistance, wear resistance and friction coefficient stability. The addition of Ti3SiC2 can improve strength, hardness and wear resistance of copper-graphite alloy material without affecting its self-lubricating properties and electrical conductivity. Two dimensional graphene has become an attractive composite reinforcement owing to their unique electrical, mechanical and thermal properties. Cu/Ti3SiC2/C/Graphene naocomposite materials reinforced with graphene have been fabricated by vacuum hot-pressing sintering and hot isostatic pressing. Microstructures and mechanical properties of Cu/Ti3SiC2/C/Graphene naocomposite materials with different graphene contents have been systematically investigated. Microstructures of the composites were examined by optical microscopy, X-ray diffraction, back scattered electron imaging, scanning electron microscope with energy dispersive spectrometer and transmission electron microscope. The mechanical properties were determined from Brinell hardness, tensile, compressive and shear tests. Results demonstrated that there was an optimum value of graphene content which has an impact on microstructures and mechanical properties of Cu/Ti3SiC2/C/Graphene naocomposite materials. Based on graphene content on microstructure and mechanical properties of Cu/Ti3SiC2/C/Graphene naocomposite materials, strengthening and fracture mechanisms by graphene reinforcement have been analyzed.
10.1016-j.compositesb.2019.01.077	-1		This work deals mechanical and tribological properties of pure copper, reinforced by various weight percentages of tin, before and after the application of equal channel angular pressing. It is found that the hardness, yield, and ultimate shear strengths are considerably improved through ECAP due to grain refinement. The effect of ECAP process on mechanical properties of dilute copper alloys is more significant than that of the pure condition. Also, the strengthening behavior is slightly intensified by increasing the amount of tin content in pure copper. Additionally, work-hardening potential of CP-Cu is restricted due to the ECAP process and also, through the production of dilute copper alloys. The results showed that the effect of ECAP on friction coefficient reduction is more sizeable than making the dilute alloys. Furthermore, the reduction of electrical conductivity in the deformed materials relies on the lattice distortion increase of copper due to the addition of Sn to Cu and the increment of dislocations density. Finally, ECAP procedure and alloying together, terminate to the better wear response of the materials.
10.1016-j.compositesb.2019.106940	4	transformation; martensite; martensitic; phase; shape; beta; memory; shape memory; temperature; temperatures; martensitic transformation; gamma; transformation temperatures; effect; thermal	In this study, Cu-based shape memory alloy (a smart material) with a new quaternary Cu-22.78Al-2.59Fe-2.44Mn (at%) composition was produced by arc melting and the samples cut from this cast-ingot alloy were homogenized at 900 degrees C for 1 h and quenched in traditional iced-brine water. Then except keeping one as the reference the others were all heat-treated (aged) at 200 degrees C for 1 h and then quenched/cooled in several different media. To find out the effects of the aging and varied quenching/cooling media types on the characteristic martensitic transformation temperatures, thermodynamical parameters and structural properties of this CuAlFeMn shape memory alloy (SMA) the thermal and X-ray measurements were carried out. The differential scanning calorimetry (DSC) and differential thermal analysis (DTA) measurements were made at different heating/cooling rates for all of the different types of the alloy samples. Thermal results showed that the characteristic forward martensite to austenite and backward phase transitions occurred at varied temperatures in between 44 and 176 degrees C and the different samples had different characteristic transformation temperatures and hysteresis due to the different quenching media effects. All of the samples exhibited high temperature shape memory alloy (HTSMA) behavior since all of their austenite start temperatures came up over 100 degrees C. The highest average austenite phase finish temperature belonged to the sample quenched in boiling water and the lowest belonged to the sample quenched in liquid nitrogen. The least amount of transformation entalphy and entropy change values were found for the aged sample quenched in liquid nitrogen which is the fastest coolant medium among others and caused the neatest martensite and interface formations and this was also understood from this sample having the lowest Gibbs free energy difference (Delta G). The X-ray analyses of the CuAlFeMn SMA samples showed the formations of beta 1'(M18R) and gamma 1'(2H) in the alloy and a main peak plane change occurred by aging. Besides this, there has been an adverse magnitude ranking correspondency found between average crystallite size and entropy change values of the aged samples. The analyses showed that the characteristic thermodynamical, thermoelastical and structural parameters of the CuAlFeMn high temperature shape memory alloy are strongly affected from the conditions of composition, aging temperature and quenching/coolant medium type used and the different combinations of those conditions can lead to their own distinctive genuine consequences.
10.1016-j.compositesb.2021.109567	-1		The wide application of Cu-Cr composites is greatly limited by their trade-off of tensile strength and electrical conductivity. In this work, we employed an industrial method of rotary swaging (RS) and subsequent aging to improve the combination of strength and electrical conductivity of Cu-3.11Cr composite wire and reveal the microstructural evolutions during the processes. It is found that the matrix grains of Cu-3.11Cr have been significantly refined and elongated during the deformation and a fibrous structure has been formed. The average diameter of the grains has been reduced to about 3.9 mu m after RS processing for an equivalent strain similar to 3.5. Moreover, most of the initial micron sized Cr particles are elongated severely along axial direction which plays a role of fiber composite strengthening and reduces the scattering effect of electrons. Besides, lots of nano sized Cr particles re-precipitated in the matrix during the subsequent aging process. After the two-stage swaging and aging, the Cu-3.11Cr composite wire obtained a good comprehensive property with an ultimate tensile strength of 580 MPa and the electrical conductivity of 81.1% IACS (international annealed copper standard). We rationalized the high strength is attributed to dislocation, grain refinement, dispersion and precipitation as well as fiber-composite strengthening. The precipitation of Cr atoms from the Cu matrix during the aging treatment is vital for the enhancement of the electrical conductivity without loss of strength . These findings can provide some new insights in the mass production of the high performance Cu-Cr composites.
10.1016-j.compositesb.2023.110823	-1		Amorphous alloy composites (AACs) comprising reinforcing crystalline phases exhibit far better mechanical properties than their base amorphous alloy counterparts, and Cu-Zr based alloys consisting of B2 phase particles embedded in an amorphous matrix are well-researched AACs in this respect. Traditionally, the B2 particles in Cu-Zr based AACs may appear to be homogeneously crystalline (without any amorphous phase inside), the glassy matrix homogeneously amorphous, and their interfaces atomically sharp. Yet, such a picture would pose difficulties in understanding how crystallization can happen in the glassy matrix, since the crystallized product is denser than but iso-stoichiometric with the matrix. The present work provides insights into this puzzle, by using electron microscopy, nanoindentation and molecular dynamics (MD) simulations to investigate the structures and mechanical properties of the crystalline and amorphous phases, and their interfaces in a Cu62Zr34.5Al3Nb0.5 AAC. Surprisingly, in this AAC, the superficially crystalline particles with tens to hundreds of microns large are found to be heterogeneous at the sub-micron scale, comprising nano-crystallites embedded in a glassy matrix, and the amorphous phase outside also exhibits a gradient in free volume content towards the interface. Smaller particles containing only B2 nano-crystallites are found to be softer than the amorphous matrix, while larger particles are harder than the amorphous phase due to martensitic transformation into the B19' phase. MD simulations indicate that the B2 phase is marginally more stable than the glassy state, and on crystallization the densification leads to free-volume generation in the surrounding glassy matrix as observed experimentally. Mechanics analysis indicates that the strain energy in the glassy matrix associated with free-volume generation scales with the volume of the crystallization, as would be the crystallization energy itself. Hence, crystallization in the AAC leading to a two-phase structure is a spontaneous but kinetically limiting process arising from the net energy difference between the crystallization energy and free-volume energy produced in the glassy matrix. This work provides a detailed understanding of the heterogeneity in the microstructures in Cu-Zr based AACs, to shed light on the crystallization of the iso-stoichiometric B2 phase from the amorphous phase.
10.1016-j.compositesb.2023.110965	-1		High temperature self-lubricating materials including composites or coatings exhibit remarkable tribological property but typically suffer from poor ductility. Therefore, striking a fine balance between these two properties is a great challenge. In this work, series of high-temperature self-lubricating Cu100-x(Ni3Al1)(x/4) superalloys were obtained, and it possesses both good tensile strength at room temperature or high temperature and appreciable elongation value (its elongation can reach up to 3%). Compared with other high temperature self-lubricating materials, it has already made great progress in the aspect of mechanical property. The results showed that the source for remarkable high temperature tribological properties derives from the synergistic effect of naturally formed oxide scale and high temperature bearing capacity. In the naturally formed oxide scale, the CuO layer provides excellent lubrication action due to those unique advantages, such as easy to shear, formation of twinning and brittle-ductile transition at high temperature. Additionally, the existence of substantial coherent interfaces hinders the crack initiation. The dense and continuous & gamma;-Al2O3 protective layer can hinder the diffusion of the oxygen anions and metal cations, which is beneficial to inhibit the further oxidation of the alloy. The work provides a novel strategy for the design and preparation of high temperature self-lubricating materials.
10.1016-j.compositesb.2024.111371	-1		The trade -off relationship of strength and ductility of metals leads to a strength increase accompanied by a ductility decrease. In the past two decades, despite significant efforts to increase strength while minimizing the ductility loss by tailoring microstructures, it has been rare to achieve simultaneous enhancement in strength and ductility, i.e., to disrupt the trade -off relationship. Here via rotary swaging and subsequent annealing, we prepared a macro dual-cable structured Cu-Al alloy rod with an inner micro -grain (MG) core (2.2 mm in diameter, 54% volume fraction) wrapped in an outer ultrafine-grain (UFG) shell (a thickness of 0.4 mm). Tensile tests revealed that the inner core has a yield strength of 472 MPa and a ductility of 29.1%, while the wrapping of the outer shell simultaneously enhances the yield strength to 552 MPa and ductility to 31.9%, respectively. The analysis of strain during the stretching process shows that the shell has a strong restraining effect on the core. Microstructure characterization indicates that the core blocks the propagation of the shear bands of shell and maximizes its density. At the same time, the restriction of the shell increases the lattice defect accumulation and work hardening ability as well as ductility of the core. Our research not only provides a method for preparing macro dual-cable structured materials with industrial scale and clean interface, but also explores a new strategy for simultaneously enhancing strength and ductility of metals, which designs macro millimeter-scale structures instead of adjusting microstructure from the micrometer scale.
10.1016-j.compositesb.2024.111667	-1		W-Cu composites are integrated materials with both structural and functional properties. However, the weak interfacial bonding capability leads to limited strain hardening, which makes it difficult to take full advantage of the coordination of the biphasic materials. In present work, a multistage strain-hardening (MSH) effect is created, which enables the W-Cu composites to possess a persistent and effective strain-hardening capability. The prepared W-30(CuAl5) (wt%) alloy has significant tensile ductility (-21 %) and ultra-high yield strength (-840 MPa). Remarkably, compared to the original W-30Cu without Al alloying, the strength and ductility are over two and three times, respectively, accompanied by the preservation of an electrical conductivity of about 80 %. This excellent synergistic effect stems from the Al-mediated interpenetrating interfacial diffusion layers and matrixnanoclusters interconnection networks. As a result, a high-density of dislocation segments, self-locking structures, and a variety of twinning mechanisms such as nanotwins and 9R configurations are sequentially activated, allowing the composites to accommodate ductility deformation while simultaneously facilitating interactions that produce three unusual rises in strain-hardening rate. The present work offers a critical perspective on the realization of a synergistic ultrahigh tensile ductility and strength combination in metal matrix composites.
10.1016-j.compositesb.2025.112311	10	composites; nanoparticles; strength; matrix; high; strengthening; particles; conductivity; composite; electrical; mpa; sintering; ods; grains; mechanical	Copper-based materials strengthened by a second phase are widely used in electrical industrial devices due to their high strength and high electrical conductivity. However, traditional uniformly dispersed materials have inherent limitations, which restrict their overall performance. Here, we develop a new hierarchical structure strategy to overcome this issue in copper-based materials by combining in-situ synthesized copper matrix composite powders with routine powder metallurgy processes. Based on the rapidly solidified microstructure of the composite powder, the submicron TiB2 particles with a high volume fraction formed by a liquid state in-situ reaction distribute as micro-clusters, while the nano-precipitates of B24Cu particles with high thermal stability precipitates during the sintering stage and is dispersive and homogeneously distributed. This novel hierarchical structure exhibits extraordinary work hardening capability and forms a network of low electrical resistance regions, thus leading to copper matrix composites with an ultimate tensile strength of 926 MPa and electrical conductivity as high as 79.8 % International Annealed Copper Standard, which is superior to numerous copperbased materials reinforced with ceramic second phases. The results will provide fundamental insights for the structural design of second phase strengthened copper-based materials.
10.1016-j.compscitech.2010.04.007	5	materials; thermal; heat; properties; material; welding; sintering; fusion; strength; laser; heat sink; thermal conductivity; mechanical; sink; manufacturing	Fibre or wire reinforced copper or copper alloys (Cu-MMCs) have been developed as a high temperature heat sink material in the scheme of the integrated European project Extremat. The Cu-MMC of interest for application e.g. in fusion reactors should be able to operate at 550 degrees C and posses a thermal conductivity of at least 200 W/m/K. Properties of the developed Cu-MMCs with the SCS-6 SiC-fibres and W-wires in a matrix of pure Cu or CuCrZr are discussed. W-wire reinforced CuCrZr is selected as a candidate material for application in the fusion reactor with the highest thermal loadings, i.e. in the divertor. A divertor mockup is produced which will be tested under a high heat flux of up to 20 MW/m(2).
10.1016-j.compstruct.2018.06.012	-1		Silicon carbide continuous fiber-reinforced copper matrix composites (Cu/SiCf) offer huge potential as heat sink material for high-heat-flux applications at elevated temperatures ( > 300 degrees C) owing to the beneficial combination of strong, stiff and refractory SiC fibers with a highly conducive and ductile copper matrix. As high-heat-flux components are normally subjected to large temperature fluctuations combined with thermal strain variations, degradation of the Cu/SiCf composites caused by fatigue damages under cyclic loads may affect the structural integrity of the component. In this study, the robustness of the Cu/SiCf composites under cyclic loads at different temperatures was evaluated by means of uniaxial cyclic loading tests. The stability of the cyclic deformation hysteresis curves was used as a measure of material's durability. The experimentally observed global deformation behavior was interpreted with the help of a micromechanics-based theoretical model. It was shown that the Mori-Tanaka type mean field theory could describe the cyclic loading behavior of the composite quite well with a good fitting quality between the measured and simulated saturated cyclic curves. The effects of fiber content, applied strain range and test temperature are discussed.
10.1016-j.compstruct.2022.116503	-1		Mo2C particles dispersion-strengthened copper matrix composites were fabricated by powder metallurgy and followed by a rolling process. Microstructure, mechanical properties, electrical conductivity, and softening resistance of Cu-xMo2C composites (x = 2, 5, 7 wt%) were studied systematically. Cu-5Mo2C composite exhibited the best combination of performances among the three composites. The tensile strength, hardness, and electrical conductivity of the as-rolled Cu-5Mo2C composite reached 405.3 MPa, 130.7 HV, and 88.4 % IACS, respectively. Grain boundary strengthening and dislocation strengthening were the primary strengthening mechanisms. Mo2C particles presented a stable microstructure and inhibited the grain coarsening of the matrix. The softening temperatures of annealed Cu-2Mo2C, Cu-5Mo2C, and Cu-7Mo2C composites were 680 degrees C, 770 degrees C, and 805 degrees C, respectively. These findings indicate that Mo2C particles can improve copper alloys' high-temperature softening resistance and mechanical properties.
10.1016-j.compstruct.2025.119126	14	strength; properties; conductivity; electrical; mechanical; cu-; grain; mpa; electrical conductivity; aging; precipitation; phase; mechanical properties; tensile; phases	This study proposes a novel approach combining MD simulations and experimental methods to investigate the relationship between microstructure and ablation behavior of Cu-W alloys with varying W content, prepared by the melt infiltration method. Cu-W alloys have attracted significant interest due to their unique combination of high thermal and electrical conductivity from Cu and excellent thermal stability and ablation resistance from W, making them suitable for high-temperature applications. However, understanding the influence of microstructure, particularly W content, on their ablation resistance remains challenging, especially under extreme conditions like laser ablation. The experimental results show that increasing W content enhances the ablation resistance, as evidenced by the smallest ablation craters in W90. MD simulations further reveal how heat predominantly diffuses through Cu regions, while W serves as a thermal barrier, thereby enhancing stability during ablation. Additionally, mean squared displacement analysis indicates that atomic mobility decreases with higher W content, suggesting greater structural rigidity in W-rich alloys. This MD-based approach successfully captures the rapid phase transformations and kinetic mechanisms of Cu-W alloys under extreme conditions, providing insights that bridge the scale gap in experimental observations. The results contribute valuable theoretical support for optimizing the design and ablation resistance of Cu-W alloys.
10.1016-j.conbuildmat.2022.128795	-1		Cu-Al-Mn (CAM) superelastic alloys (SEAs) have been shown to improve the seismic performance of bridges and buildings by replacing the plastic hinge steel reinforcement. Despite research on mechanical performance at the material and structural scales, there is limited data on the degradation in the properties of CAM SEAs under harsh environmental conditions; particularly, under long-term corrosion that are relevant for civil engineering struc-tures. This research aims to fill this knowledge gap by studying the long-term corrosion resistance of CAM SEAs in comparison with different types of steel reinforcing bars (rebar) used in construction. Long-term accelerated corrosion testing of CAM SEAs and four types of commonly used steel rebar, namely, mild steel (MS), high chromium steel (XS), epoxy coated steel (ES), and stainless steel (SS), was conducted up to 1,051 days. Three different diameters (U.S. #3, phi = 9.53 mm; U.S. #5, phi = 15.88 mm, and U.S. #10, phi = 32.26 mm) of steel rebar were considered to determine the effect of bar size on the corrosion rate. Mechanical tests were conducted after specimens reached predetermined corrosion levels. The critical mechanical properties of CAM SEAs and four steel rebar were extracted and analyzed. In addition, potentiodynamic polarization tests were performed and the Tafel curves were employed to determine the corrosion rates of CAM SEAs, steel rebar and NiTi SEAs. NiTi alloy was used as a reference for being the more traditional composition used as SEAs. It was found that the corrosion resistance of CAM SEAs is higher than MS and XS, but lower than NiTi SEA, SS and ES. The superelasticity, particularly the strain recovery, of CAM SEAs showed almost no degradation after over three years of corrosion. The experimental data and control groups in this research provide detailed evaluation of the corrosion resistance of CAM SEAs and guides the application of CAM SEAs in harsh environmental conditions.
10.1016-j.conbuildmat.2024.135862	3	sma; shape; shape memory; memory; smas; superelastic; bars; damping; cu-al-mn; mechanical; bending; applications; numerical; sma bars; material	Cu-Al-Mn (CAM) superelastic alloy bars (SEAs) have received increasing attention in bridge applications. To take full advantage of their strain recovery and energy dissipation capacity, CAM SEAs are usually only applied in the plastic hinge regions of columns as part of the longitudinal reinforcement and coupled with steel rebar through mechanical splices. In this study, the feasibility of using headed coupling to connect large diameter CAM SEAs with steel rebar was investigated. Five large diameter CAM SEAs with headed ends were prepared: one 30 mm diameter and four 20 mm diameter samples. First, mechanical tests were performed on the five headed samples where each sample was coupled with one steel rebar at each end. Monotonic, incremental and constant strain cyclic loading was applied to simulate earthquake loading. The key mechanical properties were extracted and discussed. Second, microstructural analyses including electron backscatter diffraction (EBSD), metallographic imaging, Vickers hardness testing and fractographic evaluation were performed. The crystal orientation, phase composition and fracture surfaces were investigated to understand the effect of heading process on the stress induced martensitic transformation (SIMT), phase composition and failure of the headed CAM SEAs. It was found that the heading process only affects the near end portion of the specimen and it has no influence in the middle portion of the bars. Therefore, the strain recovery capacity of the CAM SEAs after heading was not reduced. Heading process led to high density of bainite phase precipitation at the end portions, which strengthened the sample. In order to uniformly strengthen the headed end of large diameter CAM SEAs, the key is to ensure a consistent cooling rate in the central and peripheral regions of the headed end after the heading process.
10.1016-j.conbuildmat.2024.138200	-1		Concrete corrosion in wastewater pipelines is caused by biogenic sulfuric acid produced locally by sulfuroxidizing microorganisms. Concrete mixtures are commonly modified to prevent this form of corrosion by adding biocides to inhibit their biological activities. However, using biocides is not always desirable because of their limited lifespan and potential for leaching into the environment. Therefore, there is a need to develop more durable alternatives to prevent microbial-induced corrosion of concrete. In this study, three types of Cu-Ti amorphous alloys (Cu35Ti65, Cu50Ti50, and Cu65Ti35) were prepared by ball milling, and compared with commercially available TiO2 nanoparticles to assess their effects on the resistance of the microbial-induced corrosion performance of mortar. Detailed investigations were conducted on the appearance, mechanical properties, and corrosion depth of mortars at various exposure durations in an accelerated biocorrosion environment. The results revealed that the mortars mixed with Cu35Ti65, Cu50Ti50, Cu65Ti35, and TiO2 nanoparticles exhibited significantly better resistance to microbial-induced corrosion than the reference mortars. The resistance to microbial-induced corrosion of the mortar mixed with Cu50Ti50 was the best. The superior antimicrobial corrosion performance of the mortar containing Cu-Ti amorphous alloy is influenced by both smaller particle sizes and higher sterilization performance. These findings can contribute to the development of novel applications of amorphous alloys in functional concrete.
10.1016-j.corsci.2005.08.020	2	corrosion; surface; film; electrochemical; films; spectroscopy; layer; current; solution; potential; resistance; composition; x-ray; ions; showed	Investigation of the electrochemical behaviour of Cu-10Sn (wt%) alloy has been conducted in aerated aqueous sulphate solution and compared to that of pure Cu and Sn. Eoc versus time and cathodic and anodic polarizations have been performed as a function of the initial sulphate concentration, the rotation speed of the electrode and the immersion time. The surface layer have been characterized by scanning electron microscopy (SEM) and analyzed by energy dispersive spectrometry (EDS) and Fourier transform infrared spectroscopy (FTIR). The anodic behaviour evidences a Cu dissolution phenomenon on the corrosion layer limited by migration process rather than diffusion. The corrosion process conducts to preserve the original surface of the electrode and conducts to an internal growth at the layer/alloy interface, from the initial surface towards the unaltered substrate. The interphase behaviour is governed by the layer formed at Eoe under the experimental conditions and its evolution during the time. Hydroxyl-oxy and sulphate Cu and Sn compounds recover the surface and confer to the interface a blocking behaviour mainly due to the presence of the tin compounds in the layer. The global interphase behaviour matches the Type-I model of blocking adherent layer with decuprification phenomenon evidenced on archaeological bronzes.
10.1016-j.corsci.2006.07.001	2	corrosion; surface; film; electrochemical; films; spectroscopy; layer; current; solution; potential; resistance; composition; x-ray; ions; showed	The electrochemical behaviour of Cu-40Zn alloy, in 3% NaCl medium pure and polluted by 2 ppm of S2- ions, has been studied in the absence and presence of the 3-amino-1,2,4 triazole (ATA) as corrosion inhibitor. Electrochemical measurements (polarisation curves and electrochemical impedance spectroscopy) showed that sulphides accelerate the alloy corrosion. The studies revealed that ATA inhibits both cathodic and anodic reactions, indicating a mixed type of inhibition. The inhibiting effect was higher in presence of S2- ions than in its absence. Scanning electron microscopy analysis showed that the inhibitor acts by preventing the adsorption of S2- ions, and formation of CuzS at the alloy surface. The inhibition efficiency reaches 98% at a concentration of 5 x 10(-3) M.
10.1016-j.corsci.2006.07.003	2	corrosion; surface; film; electrochemical; films; spectroscopy; layer; current; solution; potential; resistance; composition; x-ray; ions; showed	The corrosion behavior of the 70/30 Cu-Ni alloy in stagnant, aerated pristine and sulfide-containing simulated seawater as a function of exposure time was investigated with polarization curve measurement and electrochemical impedance spectroscopy (EIS). It was demonstrated that the compact protective oxide film formed on the 70/30 Cu-Ni alloy resulted in the decrease of corrosion rate in aerated pristine seawater; while the corrosion rate of 70/30 Cu-Ni alloy in aerated sulfide-containing seawater increased dramatically due to the catalysis of the sulfide ions or sulfide scale for both the cathodic and anodic reactions. The impedance spectra and the corresponding equivalent circuits confirmed that a duplex layer of a surface film was formed on the 70/30 Cu-Ni alloy in aerated pristine seawater after a period of time and that the inner layer was responsible for the good resistance of the alloy; while only a porous and non-protective corrosion product layer formed on the 70/ 30 Cu-Ni alloy in aerated sulfide-containing seawater, which made small values of charge transfer resistance (Rct) to last for a abnormally long time by interfering with the growth of the protective oxide film. The composition of the surface film on the alloy in pristine and sulfide-containing seawater for different exposure times were investigated thoroughly by XPS. It was found that the duplex corrosion product layer formed on the alloy in pristine seawater was composed of an inner CU20 and an outer CuO layer. The porous and non-protective corrosion product layer formed on the alloy in aerated sulfide-containing seawater was a mixture of CuCl, Cu2S, NiS, Cu2O and NiO with trace amounts of CuO and Ni(OH)(2) and that the most significant component was Cu2S. In addition, SEM was used to analyze the topography of the 70/30 Cu-Ni alloy in both solutions after different exposure times.
10.1016-j.corsci.2006.12.018	-1		The oxidation of a quaternary Cu-Ni-Cr-Fe alloy containing approximately 20 at% Ni, 20 at% Cr and 5 at% Fe, balance Cu (Cu-20Ni-20Cr-5Fe), was studied at 700-900 degrees C in 1 atm of pure oxygen. The alloy is composed of a mixture of three phases, where the lightest alpha phase with the largest Cu content forms the matrix, while the other two, much richer in Cr, form a dispersion of isolated particles. At variance with the ternary three-phase Cu-20Ni-20Cr alloy examined previously, which was unable to form protective chromia scales over the alloy surface even after an extended period of oxidation, the present alloy formed complex external scales containing mixtures of the oxides of the various components plus a deep internal region containing a mixture of alloy and oxide phases. With time, a very irregular and thin but essentially continuous chromia layer formed at the bottom of the mixed internal oxidation region, producing a gradual decrease of the oxidation rate. Thus, the addition of 5 at% Fe to Cu-20Ni-20Cr alloy is able to decrease the critical Cr content required to form the most stable oxide and promotes the formation of a continuous chromia scale under a lower Cr content in spite of the simultaneous presence of three different phases.
10.1016-j.corsci.2007.01.013	2	corrosion; surface; film; electrochemical; films; spectroscopy; layer; current; solution; potential; resistance; composition; x-ray; ions; showed	Investigation of the electrochemical behaviour of Cu-10Sn (wt%) alloy has been conducted in aerated aqueous chloride solutions and compared to that of pure Cu and Sn. Cathodic and anodic bronze behaviours have been investigated in function of the chloride concentrations (0.1-0.001 M), the rotation speed of the electrode and the potential sweep rate after 1-h immersion time in open-circuit conditions. At the corrosion potential, the corrosion behaviour appears determined by the charge-transfer controlled reduction of oxygen and the mixed charge- and mass-transfer controlled electrodissolution. In 0.1 M NaCl solution, three anodic regions are evidenced corresponding to: (I) a dissolution part from Eoc value, (II) a maximum current region corresponding to peaks formation and (III) a large current plateau. A partial protective effect of the corrosion product layer is observed at high anodic potential. It has been interpreted as the result of a 3D growth mechanism involving the formation of stable tin species in the layer according to a pore resistance model. Results on synthetic alloy are compared with those obtained on an archaeological bronze with a similar composition immersed in the same medium. Equivalent interface behaviour is evidenced between the synthetic and the archaeological bronzes.
10.1016-j.corsci.2007.04.009	2	corrosion; surface; film; electrochemical; films; spectroscopy; layer; current; solution; potential; resistance; composition; x-ray; ions; showed	A comparative study of the corrosion behavior of the 70/30 Cu-Ni alloy in a nutrient-rich simulated seawater-based nutrient-rich medium in the presence and the absence of a marine aerobic Pseudomonas bacterium was carried out by electrochemical experiments, microscopic methods and X-ray photoelectron spectroscopy (XPS). The results of Tafel plot measurements showed the noticeable increase in the corrosion rate of the alloy in the presence of the Pseudomonas bacteria as compared to the corresponding control samples. The E IS data demonstrated that the charge transfer resistance, R, and the resistance of oxide film, R-f, gradually increased with time in the abiotic medium; whereas, both of them dramatically decreased with time in the biotic medium inoculated with the Pseudomonas, indicative of the acceleration of corrosion rates of the alloy. The bacterial cells preferentially attached themselves to the alloy surface to form patchy or blotchy biofilms, as observed by fluorescent microscopy (FM). Scanning electron microscopy (SEM) images revealed the occurrence of micro-pitting corrosion underneath the biofilms on the alloy surface after the biofilm removal. XPS studies presented the evolution of the passive film on the alloy surface with time in the presence and the absence of the Pseudomonas bacteria under experimental conditions, and further revealed that the presence of the Pseudomonas cells and its extra-cellular polymers (EPS) on the alloy surface retarded the formation process or impaired the protective nature of the oxide film. Furthermore, XPS results verified the difference in the chelating functional groups between the conditioning layers and the bacterial cells and the EPS in the biofilms, which was believed to connect with the loss of the passivity of the protective oxide film.
10.1016-j.corsci.2007.09.010	6	grain; deformation; strain; strength; dislocation; cu-; tensile; size; ecap; grain size; sfe; ductility; hardening; high; stress	The stress corrosion cracking (SCC) of a commercial Cu-30%, Zn alloy has been investigated as a function of applied stress in Mattsson solutions with pH 7.0 and 10.0 at 313 K by using a constant load method. It was found that the elongation behavior at pH 10.0 showed clearly the step wise fashion, while that at pH 7.0 did slightly, almost over the whole applied stress. The steady state elongation rate obtained from corrosion elongation curve became a relevant parameter for predicting time to failure. Furthermore, from the results obtained, it is deduced that a unified SCC mechanism is qualitatively proposed to explain both of transgranular SCC (TGSCC) at pH 10.0 and intergranular SCC (IGSCC) at pH 7.0, where the unified SCC mechanism is basically based on a film rupture-formation event at crack tips.
10.1016-j.corsci.2007.11.007	-1		Copper hollow spheres were created on porous iron particles by electro-less deposition. The consequent Ni plating was applied to improve the mechanical properties of copper hollow micro-particles. Corrosion properties of coated hollow spheres were investigated using potentiodynamic polarisation method in 1 mol dm(-3) NaCl solution. Surface morphology and composition were studied by scanning electron microscopy (SEM), light microscopy (LM) and energy-dispersive X-ray spectroscopy (EDX). Original iron particles, uncoated copper spheres and iron particles coated with nickel were studied as the reference materials. The effect of particle composition, particularly Ni content on the corrosion potential value was investigated. The results indicated that an increase in the amount of Ni coating layer deteriorated corrosion resistivity of coated copper spheres. Amount of Ni coating layer depended on conditions of Ni electrolysis, mainly on electrolysis time and current intensity. Corrosion behaviour of sintered particles was also explored by potentiodynamic polarisation experiments for the sake of comparison. Formation of iron rich micro-volumes on the particle surface during sintering caused the corrosion potential shift towards more negative values. A detailed study of the morphological changes between non-sintered and sintered micro-particles provided explanation of differences in corrosion potential (E-corr).
10.1016-j.corsci.2009.04.002	2	corrosion; surface; film; electrochemical; films; spectroscopy; layer; current; solution; potential; resistance; composition; x-ray; ions; showed	The binary bronze alloy Cu-6Sn corrosion, and formation and properties of corrosion product layer (patinas) during 12 days of exposure to 15 mM Na2SO4 aqueous solution were investigated by a range of diverse experimental techniques. For the reasons of comparison, some techniques were applied, in parallel, to copper. Gravimetric measurements revealed lower corrosion rates of bronze than those of copper, probably caused by the presence of tin compounds in the corrosion product layer. Cyclic voltammetry results showed that the oxidation processes on bronze are affected by the formation of tin oxide species. Electrochemical impedance spectroscopy showed that, as opposed to copper which produced only two time constants, bronze corrosion resistance was dominated by the additional high-frequency time constant representing redox processes occurring at the corrosion product surface. SEM, ATR FTIR and PIXE results suggest that Cu-6Sn bronze corrosion in 15 mM Na2SO4 solution was impeded by the formation of two-layered structure of corrosion products that formed due to selective dissolution of copper at the layer/solution interface, leaving the outer layer enriched in highly corrosion resistant Sn oxi/hydrohide species.
10.1016-j.corsci.2009.05.052	2	corrosion; surface; film; electrochemical; films; spectroscopy; layer; current; solution; potential; resistance; composition; x-ray; ions; showed	Potentiostatic electrodeposition was used to produce Cu-Ni multilayer by two-wave pulse plating technique from sulphate/citrate electrolyte at pH 4. Cyclic voltammetry studies provide information about the deposition potential. The compositions of multilayers were studied using X-ray fluorescence (XRF). Electrochemical corrosion studies of the deposited multilayer on copper were studied by potentiodynamic polarization and electrochemical impedance spectroscopy (EIS). The surface of the layer having smooth, small grain and compact structure was confirmed by scanning electron microscopy (SEM) and atomic force microscopy (AFM) analysis. The face centered cubic lattices are present in the Ni-Cu multilayer and this is confirmed by the X-ray diffraction (XRD) data. The multilayer structures have better corrosion resistance than the base substrate.
10.1016-j.corsci.2012.03.003	2	corrosion; surface; film; electrochemical; films; spectroscopy; layer; current; solution; potential; resistance; composition; x-ray; ions; showed	Corrosion inhibitors, associated or not with protective coatings, may be a good solution for planned conservation activities in the case of bronze and gilded bronze artworks. In this work, alternatives to BTA for the inhibition of bronzes and gilded bronze are investigated. The experimentation includes a screening of many organic substances as film-forming corrosion inhibitors for a copper alloy reproducing the composition and the microstructure of a Renaissance leaded bronze. The results, obtained after exposure to 3.5 wt% NaCl solution or concentrated artificial rain, show that, if proper curing conditions are adopted, excellent protective properties are offered by 3-mercaptopropyltrimetoxysilane.
10.1016-j.corsci.2012.06.015	2	corrosion; surface; film; electrochemical; films; spectroscopy; layer; current; solution; potential; resistance; composition; x-ray; ions; showed	The corrosion behavior of Cu-Sn intermetallics was investigated in 3.5 wt% NaCl solutions and compared to that of Cu and Sn by using galvanic corrosion and polarization methods. Polarization curves showed that an increase in the Cu content increased the corrosion current density and shifted both corrosion potential and breakdown potential towards more noble values. The corrosion products on the surface of Sn, Cu and Cu3Sn were Sn3O(OH)(2)Cl-2. CuCl, and co-existing phases CuCI and Sn3O(OH)(2)Cl-2, respectively. In addition, the SnO2, Sn3O(OH)(2)Cl-2, Cu2O, and CuCl2 center dot 3Cu(OH)(2) were observed in the Cu6Sn5 phase.
10.1016-j.corsci.2012.09.018	11	glass; bulk; metallic; bulk metallic; gfa; bmg; glassy; metallic glass; ability; bulk metallic glass; amorphous; addition; crystallization; mm; glass-forming	In the present study, we propose that the formation of amorphous oxide layers with an enhanced thermal stability can significantly improve the oxidation resistance of metallic glass in the supercooled liquid (SCL) state. Addition of a small amount of Be (2 at%) in Cu46Zr46Al8 widens the SCL region and simultaneously improves the oxidation resistance of the SCL. For Cu46Zr46Al8, the initial amorphous oxide completely transforms into the crystalline oxide far below the glass transition temperature during continuous heating, while for Cu45Zr45Al8Be2, the amorphous oxide remains after heating up to the SCL region, thus significantly improving the oxidation resistance of the SCL.
10.1016-j.corsci.2012.10.017	2	corrosion; surface; film; electrochemical; films; spectroscopy; layer; current; solution; potential; resistance; composition; x-ray; ions; showed	By immersing polycrystalline Cu in a solution of 0.1 M NaCl and 0.5 M Na2SO4 the grain dependent electrochemical behavior is studied. In order to exclude possible compositional effects, high purity Cu was used. With the use of Atomic Force Microscopy (AFM) and Electron Backscatter Diffraction (EBSD) it was possible to link the dissolution behavior of a polycrystalline material to specific crystallographic features. The results suggest that the grain orientation has no major influence on the corrosion kinetics. On the other hand, the orientation of the neighboring grains seems to play a decisive role in the dissolution rate.
10.1016-j.corsci.2013.04.007	-1		Ultrafine-grained (UFG) copper was prepared by facile machining procedure. High resolution transmission electron microscopy images revealed that, in UFG Cu, minimum grain size of 80 nm could be formed when a small machining rake angle was applied. The electrochemical corrosion behavior of UFG Cu in 0.5 M HCl was investigated by potentiodynamic polarization and electrochemical impedance spectroscopy. Comparing with coarse-grained Cu, UFG Cu exhibited notably declined corrosion current density. Particularly, when the size of Cu grains were reduced from 500 gm to 80 nm, the charge transfer resistance of anodic dissolution step dramatically increased from 200 to 621 Omega cm(2).
10.1016-j.corsci.2013.05.014	2	corrosion; surface; film; electrochemical; films; spectroscopy; layer; current; solution; potential; resistance; composition; x-ray; ions; showed	This work presents a self-healing protective coating for copper. The complex coating is composed of copper(II) 8-hydroxyquinolinate (Cu(8HQ)(2)) 3D network film storing corrosion inhibitor as base layer and epoxy as top layer covering on the base layer. The results of EIS and polarization curves reveal the self-healing effect of Cu(8HQ)(2) 3D network film with corrosion inhibitor embedded. After being scratched with a knife-edge, the complex coating rapidly releases inhibitor embedded in 3D network structure to suppress the corrosion process. The scratch on the coating is covered with inhibitor adsorption film and the anodic activity is restrained.
10.1016-j.corsci.2013.05.026	2	corrosion; surface; film; electrochemical; films; spectroscopy; layer; current; solution; potential; resistance; composition; x-ray; ions; showed	A novel gold-imitation copper alloy (CuZnAlNiSnBRe) was designed and its corrosion behavior in salt spray environment was investigated. The new alloy has better tarnish resistance and corrosion resistance than the current coinage alloy used in China (H7211). A multi-layer film formed on the surface of the new alloy after a period of exposure to salt spray was responsible for the good resistance of the alloy. The corrosion products were a mixture of CuO, Cu2O, ZnO, Al2O3 and Al(OH)(3), with the transition from Cu2O to CuO occurring during the corrosion process.
10.1016-j.corsci.2013.07.015	2	corrosion; surface; film; electrochemical; films; spectroscopy; layer; current; solution; potential; resistance; composition; x-ray; ions; showed	Commercial purity copper and four commercial copper alloys were studied to determine their color stability during prolonged hand contact and their corrosion resistance in synthetic sweat containing 0.8% sodium chloride and 3% acetic acid. The hand baton test showed that alloys C752 and C706 with high nickel content remained shiny after two years of exposure to hand contact whereas C110 and alloys C260 and C510 became dark and dull. Glancing Angle X-ray Diffraction showed the presence of cuprous oxide Cu2O on the copper alloys with a thickness between 50 and 230 nm, as determined by chronopotentiometry. The dark appearance of C110, C260 and C510 after hand contact was the consequence of the reflection of light from a rough and porous surface, as verified by Scanning Electron Microscopy. The nickel in the copper alloys kept the alloys shiny with good color stability by keeping a smoother surface. Electrochemical Impedance Spectroscopy showed that copper C110 and brass C260 had the best corrosion resistance, followed by C510 and alloys C706 and C752 had the lowest corrosion resistance, all tested in synthetic sweat. The nickel containing alloys corroded approximately 40 times faster than the C110 in the synthetic sweat. This suggests that the color stable surface of the Cu-Ni samples on the hand baton was the result of higher corrosion rates in hand sweat rather than better corrosion resistance. SEM studies of the samples after immersion, however, revealed very different surfaces and microstructures compared to the hand baton test. The laboratory test protocol could be improved by incorporating cyclic tests (wet and dry) and adding a rubbing component to better mimic actual hand contact.
10.1016-j.corsci.2013.07.019	2	corrosion; surface; film; electrochemical; films; spectroscopy; layer; current; solution; potential; resistance; composition; x-ray; ions; showed	Eight copper alloys were tested in a one-year field deployment in the North Atlantic Ocean. The corrosion behaviour was characterized by weight loss, optical and electronic microscopy analyses. The biofouling performance was quantified in terms of the biomass accumulation. The testing program included specimens in tensioned and untensioned configurations, as well as a set for seasonal deployments. The seasonal corrosion rates were 140% higher, and the rates of tensioned specimens were 39% higher than those of the untensioned specimens after 12 months of deployment. Good biofouling resistance was observed for all but one alloy, which exhibited heavy fouling by barnacles.
10.1016-j.corsci.2014.02.028	2	corrosion; surface; film; electrochemical; films; spectroscopy; layer; current; solution; potential; resistance; composition; x-ray; ions; showed	Metal-complex film with super-hydrophobic property is fabricated on copper (Cu) surface with one-step electrochemical method in laurylamine/ethanol solution. Dissolution-coordination-precipitation model is proposed to illuminate formation mechanism of Cu(II)-laurylamine complex film. The super-hydrophobic film can act as a barrier to corrosion of underlying copper with inhibition efficiency close to 100%, and it maintains stability within a wide potential range. The origin of such corrosion protection property is explained from view point that hierarchical micro-structure of the super-hydrophobic film can maintain a stable air/liquid interface which inhibits erosion of corrosive medium.
10.1016-j.corsci.2014.06.027	2	corrosion; surface; film; electrochemical; films; spectroscopy; layer; current; solution; potential; resistance; composition; x-ray; ions; showed	The kinetics of Cu2S (chalcocite) film growth on corroding copper surfaces were monitored by following the change in pH in anaerobic aqueous sulphide solutions. Under stagnant conditions film growth was controlled by SH- diffusion in solution, and the formation of a non-protective film allowed complete consumption of available SH-. When accelerated by convection, film growth rapidly became controlled by Cu+ transport through a coherent protective film and proceeded at a considerably slower rate.
10.1016-j.corsci.2014.08.003	2	corrosion; surface; film; electrochemical; films; spectroscopy; layer; current; solution; potential; resistance; composition; x-ray; ions; showed	Elemental zinc and copper-zinc alloys capped with a mixed-oxide layer of cuprite and zincite were exposed to SO2 vapour in a humid oxygen-free atmosphere. Elemental sulphur, zinc sulphite and some zinc hydroxide are the only products which are obtained in the anoxic sulphitation of metal zinc. The pseudo-binary system Cu2SO3Cu(1-x)ZnxSO3 center dot 2H(2)O is the result of the experiments on both thermally oxidised and naturally weathered alpha-brasses. The outcome of competition between the high-copper and the high-zinc species strongly depends on the mass action law: the greater the ZnO to Cu2O phases ratio, the higher the substitution rate of Cu(II) for Zn(II).
10.1016-j.corsci.2015.09.006	2	corrosion; surface; film; electrochemical; films; spectroscopy; layer; current; solution; potential; resistance; composition; x-ray; ions; showed	In order to prepare anode materials for testing for Al electrolysis, monophased Cu-Ni-Fe alloys were produced by high-energy ball milling with different Cu contents (65, 55 and 45 wt%) and a Ni/Fe mass ratio fixed at 1.33. A Cu-free alloy (57Ni43Fe) was also evaluated for comparison. Their oxidation behavior was studied at 700 degrees C under O-2 atmosphere and in Al electrolysis conditions. Under both conditions, it is shown that the presence of CuO in the outer layer is critical for the formation of an inner protective layer of NiFe2O4 and depends critically on the Cu content of the alloy.
10.1016-j.corsci.2015.12.015	-1		Three dimensional nanoporous copper (NPC) films with tunable thickness ranging from similar to 230 nm to similar to 2.2 mu m were fabricated by dealloying Cu-Zr-Al metallic glasses. The ductile-to-brittle transition behavior of the NPC was firstly explored. Moreover, by systematically investigating the influence of Cu content and dealloying temperature on nanoporosity, it was found that, as the Cu content increased, the pore size significantly decreased. In addition, decreasing the dealloying temperature could result in the formation of ultrafine nanoporous structure. Our current work provides bendable ultrathin NPC films with tunable nanoporosity, which is promising for functional applications in micro nano electromechanical systems.
10.1016-j.corsci.2017.02.004	2	corrosion; surface; film; electrochemical; films; spectroscopy; layer; current; solution; potential; resistance; composition; x-ray; ions; showed	A new type of composite nanoparticles (CNPs) was prepared by loading a typical inhibitor 1-hydroxybenzotriazole (HOBT) for corrosion protection of copper alloy in mesoporous silica nano-containers. The release kinetics of HOBT from CNPs in 3.5% NaCl solution was in conformity with the first order kinetic model. The open circuit potential monitoring, the morphology observation and the scanning Kelvin probe measurement of the Cu-Zn alloy in 3.5% NaCl solution with CNPs proved that a uniformly protective film was formed on the surface. Electrochemical impedance spectroscopy was employed to analyse the corrosion inhibition process of CNPs on the Cu-Zn alloy.
10.1016-j.corsci.2017.06.015	-1		Amorphous Cu66Zr34 alloy decomposes into Cu, ZrO2, and residual amorphous phase after oxidation, mainly due to differences between the oxygen affinity to Cu and Zr. A four-layer structure formed near the surface Consisting of two oxidized layers, a transition region, and the matrix. The crystalline phases exhibited a gradient distribution along the thickness. The oxidized ribbons showed an adjustable temperature coefficient of electrical resistivity as a function of thickness. Near constant electrical resistivity (TCR approximate to 0) could be obtained with a thickness of 20 mu m. Such transformation can be utilized for producing precision wires or thin-film chip resistors through oxidation.
10.1016-j.corsci.2017.11.014	2	corrosion; surface; film; electrochemical; films; spectroscopy; layer; current; solution; potential; resistance; composition; x-ray; ions; showed	The golden alloy Cu-5Zn-5Al-1Sn has found many applications because of its appearance and resistance to tarnishing. The microstructure and multi-component surface oxide of Cu-5Zn-5Al-1Sn have been investigated through a multi-analytical approach . Compared to commercial Cu metal, Cu-5Zn-5Al-1Sn has significantly smaller grains and higher fraction of coherent twin boundaries. The 5-10 nm thick oxide formed after diamond polishing has four identified sub-oxides all contributing to the overall corrosion resistance. Cu2O is mainly located in the outer part, followed by ZnO, SnO2 and Al2O3 closer to the alloy substrate. The latter three possess barrier properties, while Cu2O exhibits a more complex structure.
10.1016-j.corsci.2017.11.025	2	corrosion; surface; film; electrochemical; films; spectroscopy; layer; current; solution; potential; resistance; composition; x-ray; ions; showed	The corrosion of copper in aqueous solutions containing >= 5 x 10(-4) mol/L sulphide and the ensuing accumulation of corrosion product deposits (as chalcocite Cu2S) occurs non-uniformly indicating the occurrence of microgalvanic coupling between net anodic and net cathodic surface locations. A series of novel electrochemical experiments were designed to confirm the occurrence of this process and a series of analytical procedures used to identify the chemical nature of the transported Cu species. Transport was found to occur as copper sulphide complexes and clusters. It was also demonstrated that all the available sulphide was sequestered as deposited Cu2S.
10.1016-j.corsci.2018.05.033	2	corrosion; surface; film; electrochemical; films; spectroscopy; layer; current; solution; potential; resistance; composition; x-ray; ions; showed	Copper and its alloys are known for their antimicrobial activity, which makes them appealing materials for various touch surfaces in public facilities. These materials are also known for being prone to tarnishing, especially in contact with human palm sweat. The paper describes investigations on tarnishing of copper and various copper alloys by oxidation at elevated temperatures. After evaluation of thickness and chemical composition of oxide layers, microbiological tests were carried out in order to determine the impact of oxidation on antimicrobial efficiency of copper alloys.
10.1016-j.corsci.2018.06.031	2	corrosion; surface; film; electrochemical; films; spectroscopy; layer; current; solution; potential; resistance; composition; x-ray; ions; showed	In this work, a spinodal Copper alloy-C72900, was tested to investigate the resistance against environmentally assisted degradation. The material was tested according to ISO 15156-3 Level V in sour H2S solution and to cathodic polarization in simulated seawater with stressed samples. The results showed no indications of hydrogen stress cracking under cathodic polarization in seawater. However, cracks up to 3 mm deep were found on the samples exposed to sour H2S environment. Energy Dispersive Spectroscopy showed severe depletion of copper close to the cracks which is associated with selective corrosion. Stress corrosion cracking was the dominating crack mechanism in the ISO 15156-3 Level V test.
10.1016-j.corsci.2018.10.036	2	corrosion; surface; film; electrochemical; films; spectroscopy; layer; current; solution; potential; resistance; composition; x-ray; ions; showed	The influence of hydrostatic pressure on the corrosion behavior of 90/10 copper-nickel alloy in 3.5% NaCl solution under alternating dry and wet conditions has been investigated using weight loss, SEM/EDS, XRD, XPS, EIS, etc. Results show that high pressure has a promoting effect on the corrosion of the alloy during the studied immersing period and inhibits the redeposition process of the alloy. The corrosion process of the alloy and the influence of hydrostatic pressure have been discussed.
10.1016-j.corsci.2018.11.037	-1		Homogeneous Cu65Ni20Fe15 (wt%) alloy, which is a promising anode material for zero-carbon Al production, was successfully produced by casting followed by heat treatment at 1070 degrees C for 50 h . At 700 degrees C, the homogenization procedure increases the oxidation resistance of the homogeneous Cu-Ni-Fe alloy, as confirmed by the decreased weight gain (34% less after 20 h) and parabolic rate constant k(p) (by a factor of 2.5) compared to the as-cast alloy. The oxide scale formed on the homogenized alloy is thinner, more compact and coherent, consisting of a CuO outer layer and a (NiO + Fe3O4)-rich inner layer.
10.1016-j.corsci.2019.01.002	2	corrosion; surface; film; electrochemical; films; spectroscopy; layer; current; solution; potential; resistance; composition; x-ray; ions; showed	The role of Sn on the atmospheric corrosion performance of binary Cu-Sn bronze alloys (4-6 wt% Sn) compared with Cu metal used in outdoor architecture is elucidated in terms of microstructure, native surface oxide composition, patina evolution, corrosion rates, appearance and metal release. Results are presented for non-exposed surfaces and surfaces exposed at different urban and marine sites in Europe up to 5 years and based on multi-analytical findings from microscopic, spectroscopic, electrochemical and chemical investigations. Alloying influenced the corrosion, aesthetic appearance and patina evolution, differently for urban and marine sites, whereas no effects were observed on the release pattern.
10.1016-j.corsci.2019.03.043	16	wear; composite; composites; powders; milling; particles; powder; wt; sliding; friction; hardness; matrix; mechanical; surface; properties	Higher density of 98.66 and 94.60% rho(th) (theoretical density) was achieved for hot pressed Cu and Cu-15Al alloy, respectively. The microstructure of Cu-15Al alloy consists of alpha (Cu0.78Al0.22) and gamma(2) (Cu9Al4) phases. The hardness of Cu was significantly improved (from 1.32 to 6.03 GPa) with the addition of Al. Drastic reduction in corrosion of Cu-15Al (1.6 mpy) when compared to pure Cu (20.7 mpy) was noticed despite the low densification of Cu-Al. The higher impedance of Cu-15Al alloy corroborates the formation of protective layer. This work demonstrates the efficacy of high amount of Al in improving corrosion resistance of Cu.
10.1016-j.corsci.2019.05.025	2	corrosion; surface; film; electrochemical; films; spectroscopy; layer; current; solution; potential; resistance; composition; x-ray; ions; showed	The copper patina colour has been systematically explored through a large set of short- and long-term exposed copper metal samples. The initial brown-black appearance is attributed to semiconducting properties of cuprite (Cu2O) and fully attained at thickness 0.8 +/- 0.2 mu m. The characteristic green-blue appearance is due to the colour forming Cu(II)-ion in the outer patina layer which needs to be 12 +/- 2 mu m to fully cover the inner cuprite layer. No significant influence of atmospheric environment on patina colour is discerned. The green-blue patina colour on historic copper was attained after shorter exposures than in modem copper due to more inhomogeneous microstructure.
10.1016-j.corsci.2020.108600	-1		We report dealloying of Ti60Ta40 (wt%) in molten copper, eutectic Cu28Ag72 alloy and Cu20Ag40Bi40 alloy for the fabrication of ultrafine Ta ligament structures across a 1-mm thick section. When dealloyed in molten Cu and Cu20Ag40Bi40, the melt temperature dictated the length scale of Ta ligaments, which decreased exponentially with decreasing temperature. Conversely, dealloying in molten eutectic Cu28Ag72 alloy led to complex Ta ligament structures due to the enhanced surface diffusivity of Ta by Ag. Ultrafine ( < 100 nm) Ta ligament structures were produced by dealloying in molten Cu20Ag40Bi40 at 650 degrees C due to both low melt temperature and low surface diffusivity of Ta.
10.1016-j.corsci.2020.108865	2	corrosion; surface; film; electrochemical; films; spectroscopy; layer; current; solution; potential; resistance; composition; x-ray; ions; showed	A drastic alteration resumption observed on archaeological bronze objects was investigated, characterized by crystals growing under the surface of the objects, inducing cracks, desquamation and detachment of patina scales. Analyses shown that artefacts were covered by a thick layer of covellite CuS, which proved to be air-stable. On the contrary, Cu-Sn-S compounds (mohite and kuramite), replacing the alloy in the bulk, showed an extreme reactivity towards air and a rapid transformation into hydrated copper sulfates. This phenomenon was unknown in the restoration field and an overall alteration process, from abandonment until exhibition, implying occurrence mechanisms of alteration products, is proposed.
10.1016-j.corsci.2020.108996	-1		The competition between synchronous oxidation and preferential oxidation of Zr and Al in amorphous Cu-Zr-Al alloys has been investigated. Oxide-layer growth on Cu-poor Cu-Zr-Al alloys occurs by synchronous oxidation of Zr and Al. However, for relatively high Cu alloying contents, synchronous oxidation of Zr and Al becomes disturbed by the increased chemical interaction of Cu with Al, which immobilizes Cu and Al atoms from oxidation. Consequently, only Zr is preferentially oxidized. The findings provide fundamental insights on the role of nobler alloy constituents on the oxidation mechanism of multi-component alloys, which opens new avenues for rational design of surficial oxide structures.
10.1016-j.corsci.2021.109309	-1		A comparative oxidation study of homogeneous amorphous and crystalline Cu28Zr51Al21 alloys is presented to reveal the univariate role of structural order on the oxidation behavior of multi-component alloys. Amorphous Cu?Zr?Al is confirmed much more oxidation-resistant than crystalline Cu?Zr?Al. Preferential oxidation of Zr and Al occurs in both alloys, resulting in an amorphous Zr?Al?O layer and a Cu-enriched region. Cu-enrichment in the crystalline alloy causes Cu9Al4 nanocrystals embedded in the oxide. However, the Cu-enriched region in the amorphous alloy remains amorphous because of its high glass-forming ability. Findings provide design strategies for achieving highly oxidation-resistant alloys.
10.1016-j.corsci.2021.109433	2	corrosion; surface; film; electrochemical; films; spectroscopy; layer; current; solution; potential; resistance; composition; x-ray; ions; showed	The interplay between atmospheric corrosion and antimicrobial efficiency of bare Cu and Cu5Zn5Al1Sn was studied upon exposures simulating high-touch surface conditions. The survival of the bacteria Bacillus subtilis during surface contact with Cu and Cu5Zn5Al1Sn was examined under different degrees of surface oxidation, tarnishing, wettability and copper ion release. Depending on surface conditions complete bacteria inhibition was obtained within 4 min on Cu and within 6-10 min on Cu5Zn5Al1Sn. The antibacterial efficiency increases slightly with copper release rate and is governed by complex interactions between the corroded metal surface, bacteria and extracellular polymeric substances produced by the bacteria.
10.1016-j.corsci.2021.109563	2	corrosion; surface; film; electrochemical; films; spectroscopy; layer; current; solution; potential; resistance; composition; x-ray; ions; showed	Cu-Ni-Fe alloys are promising inert anodes for green Al production but their corrosion resistance must be improved. Here, protective (Co,Ni)O coatings are deposited by high velocity oxygen fuel (HVOF) process on CuNi-Fe alloys. The influence of the coating and substrate compositions on their behavior is studied at 1000 degrees C under argon and air. On Cu-rich alloy, CoxNi1_xO coatings with higher nickel content slow down oxygen diffusion to the substrate, as well as copper diffusion to the sample surface. On Ni-rich alloy, the formation of a NiFe2O4 scale is observed, whose thickness decreases as the Ni content of the CoxNi1_xO coatings increases.
10.1016-j.corsci.2021.109649	-1		The high-voltage arc corrosion behavior of Cu/ 30 vol% Ti3AlC2 composites in air, carbon dioxide, nitrogen, and sulfur hexafluoride was studied, and their corrosion mechanism was systematically discussed. Arc energy and electromagnetic force in different atmospheres lead to the different corrosion characteristics in corrosion area. Ti3AlC2 was oxidized and decomposed in air and carbon dioxide, while it maintained a good structure in nitrogen and sulfur hexafluoride. The characteristics of the arc were clearly observed by a high-speed camera. This study lays a foundation for the composition design, performance optimization and failure analysis of Cu-MAX composites in the high voltage electrical appliance.
10.1016-j.corsci.2021.109686	-1		Improving the oxidation resistance without sacrificing the electrical conductivity of Cu is of great importance for researchers due to its widespread application. In this study, oxidation resistance of Cu-5 wt%Ag alloy under solution treatment (ST) and aging treatment (AT) were studied systematically. It has been confirmed that AT sample demonstrates considerably higher oxidation resistance than ST sample at elevated temperatures. The aging treatment enhanced the formation of a continuous Ag network along grain boundaries, which could act as a barrier for both inward diffusion of oxygen and outward diffusion of Cu along grain boundaries during oxidation.
10.1016-j.corsci.2021.109888	-1		Here, a novel alloy design strategy for improving corrosion resistance of Al15(CuFeMn)85 (at%) immiscible dualphase medium-entropy alloy is proposed and verified experimentally. The corrosion resistance of the alloy significantly enhances with the addition of Cr. During the corrosion of the Cr-containing alloy, three different oxide layers of Cu-, Cr-, and Fe-rich oxide layers with a few nm thickness are sequentially formed as a layered structure. Such tri-layer oxide enhances corrosion resistance by shielding the surface of the matrix, and the corrosion resistance of the alloys is comparable to that of austenitic stainless steels.
10.1016-j.corsci.2021.110005	2	corrosion; surface; film; electrochemical; films; spectroscopy; layer; current; solution; potential; resistance; composition; x-ray; ions; showed	Composition inhomogeneity in Cu-Zn-Al-Fe-Mn alloy was determined as the coexistence of alloy matrix, Fe3Al-based kappa phase, and CuZnAl-based precipitates. The micro-galvanic corrosion behavior between the inhomogeneous phases in NaCl solutions was found to be highly dependent on pH levels. The matrix shows higher Volta potentials than that of kappa phase, but preferential corrosion and inverse nobility in neutral and acidic NaCl solutions respectively, due to the different stabilities of the surface layers. More importantly, a dense Cu layer forms on the alloy matrix in acidic NaCl solutions via a dissolution-redeposition-diffusion process, improving the overall corrosion resistance.
10.1016-j.corsci.2021.110012	-1		The oxidation behavior of the Cu66Zr34 metallic glass from room temperature to 400 degrees C is studied. Heterogeneous oxidation was observed on both the surface contacting with the rotating roller (RS) and the free surface (FS). The RS is oxidized faster than the FS, while the raised region has a quicker oxidation rate than the groove-like region on the RS. The different oxidation rates are attributed to the higher free volume content frozen in the amorphous ribbon during sample preparation. A swell-crack-outward diffusion of Cu oxidation mechanism is proposed to explain the oxidation behavior, particularly at a temperature below 200 degrees C.
10.1016-j.corsci.2022.110269	-1		The supersaturated solid-solution interfaces between Cu core and Ag shell structures improve their bonding strength and greatly prevent the outward diffusion of Cu atoms and slow down the growth of Cu oxides. The printed CuAgx electrodes maintain high conductivity for a long time even at 220 degrees C, which is far better than the conventional Cu core/Ag shell and Cu/Ag mixed structures that rapidly oxidize below 150 degrees C. These findings not only promote the broad applications of Cu core/Ag shell structures but also pave a potential way for the fabrication of various stable core/shell structure materials.
10.1016-j.corsci.2022.110304	2	corrosion; surface; film; electrochemical; films; spectroscopy; layer; current; solution; potential; resistance; composition; x-ray; ions; showed	We investigated the erosion corrosion behavior of a commercial copper tube in 1 wt% NaCl solution using a selfbuilt loop apparatus, and revealed effects of flow velocity on corrosion layer evolution that explains the flow velocity dependent corrosion rate of copper tubes in application. Furthermore, the intergranular erosion corrosion forms the detached and partially oxidized copper grains with nut structure. From core to shell, the compositions are supposed to be copper, copper-based oxygen solid solution, Cu2O with oxygen vacancies, Cu2O, and Cu2O with copper vacancies. These findings provide deepened understanding of erosion corrosion behavior of copper and copper alloys.
10.1016-j.corsci.2022.110442	2	corrosion; surface; film; electrochemical; films; spectroscopy; layer; current; solution; potential; resistance; composition; x-ray; ions; showed	Silicon bronze is widely used for monuments: corrosion of Cu-3Si-1Mn was studied with respect to Cu-5Sn-5Zn5Pb during ageing tests (runoff/full immersion) in acid rain. Surface characterisation (FEG-SEM/EDS elaborated through PCA, TEM, Raman, FTIR, profilometry), metal release and EIS measurements were performed. Under runoff conditions, where mechanical action plays a role, the alloys showed comparable corrosion resistance. In full immersion the corrosion rate of Cu-3Si-1Mn was slightly higher than that of Cu-5Sn-5Zn-5Pb, due to the different nature of the corrosion products. Results showed that, compared to Sn oxide/hydroxide, Si tends to form less protective amorphous products, detaching from the surface.
10.1016-j.corsci.2022.110911	2	corrosion; surface; film; electrochemical; films; spectroscopy; layer; current; solution; potential; resistance; composition; x-ray; ions; showed	The microbiologically influenced corrosion (MIC) of 90/10 copper-nickel (Cu-Ni) alloy in the presence of anaerobic Desulfovibrio vulgaris was investigated in this work. The corrosion rate of the alloy varied remarkably with different energy starvation levels, which was attributed to various biogenic H2S concentrations and extracellular electron transfer (EET) by D. vulgaris. The biogenic H2S caused the degradation of passive films generated on the alloy. 20 ppm (w/w) riboflavin accelerated the weight loss of alloy by 52%. The EET routes resulted in localized corrosion of Ni contained in the alloy. Two types of MIC mechanisms coexisted in the 90/10 Cu-Ni alloy MIC by D. vulgaris.
10.1016-j.corsci.2022.110917	2	corrosion; surface; film; electrochemical; films; spectroscopy; layer; current; solution; potential; resistance; composition; x-ray; ions; showed	The corrosion interface characteristics and corrosion behavior of Cu-C alloys in liquid Ga at 100-180 degrees C were studied in this paper. The corrosion mechanism of Cu-C alloys was microscopically studied via the first-principles calculation based on the density functional theory (DFT). The results, the diffusion of Ga atoms leads to the phase transition of Cu in the Cu-C alloy and the generation of the corrosion product CuGa2. The corrosion rate of the Cu-C alloy is related to the dissolution rate, and growth rate and exfoliation rate of corrosion product layer. C led to much better corrosion resistance of Cu-C alloys.
10.1016-j.corsci.2023.111281	-1		Oxidation resistance determines the applicability in high temperature atmospheric environment of the novel heat-resisting cuboidal γ′-gamma' phase coherent precipitation strengthened Cu-Ni-Al alloys, and it needs to be systematically evaluated in a wide composition range. The results indicate that the oxidation behavior of the Cu1-x(Ni3/4Al1/4)x alloys exhibits a strong composition dependence, displaying excellent oxidation resistance at 850 degrees C when x is higher than 25 at%. From multi-aspects of atom-phase-alloy, combining the microstructural investigation and first principles calculation, the formation of Al2O3 protective layer and the synergistic effect of the basic components are crucial factors for the oxidation resistance of the alloys.
10.1016-j.corsci.2023.111339	-1		The microstructure-induced high-temperature oxidation behavior of Cu-10Ni-3Al (wt%) at 800 celcius was studied through experimental methods and CALPHAD modeling. In this study, a comparative oxidation study of as-cast, homogenized and aging Cu-Ni-Al alloys is presented to reveal the role of microstructural evolution (solute segregation, distribution and concentration) on the oxidation behavior at high temperature. The results showed that the addition of solute Al in Cu-Ni alloys could promote the formation of dense Al2NiO4 and Al2O3 oxide layers and improve the oxidation resistance of the Cu alloy. The homogenized alloy demonstrates significantly higher oxidation resistance than the as-cast and aging alloys.
10.1016-j.corsci.2023.111427	2	corrosion; surface; film; electrochemical; films; spectroscopy; layer; current; solution; potential; resistance; composition; x-ray; ions; showed	The present work investigated the microbial-induced pitting behavior of the 70/30 copper-nickel (Cu-Ni) alloy. Unlike the MIC of Cu by Desulfovibrio vulgaris, the alloy exhibited considerable pitting sensitivity and pit nucleation frequency under the 10%, 50%, and 100% carbon source (CS) levels. The metastable pit was more likely to evolve into stable growth in the full-strength medium. Meanwhile, a model was established to explain the alloy pitting mechanism induced by D. vulgaris. New evidence further verified that Cu-Ni alloy MIC was not only ascribed to the biogenic H2S but the electroactive D. vulgaris biofilms via extracellular electron transfer (EET) for energy harvest.
10.1016-j.corsci.2023.111512	2	corrosion; surface; film; electrochemical; films; spectroscopy; layer; current; solution; potential; resistance; composition; x-ray; ions; showed	Microscopic aspects of electrochemical reactions in a B10 Cu-Ni alloy/2205 duplex stainless steel (DSS) galvanic couple immersed in NaCl solution were investigated by electrochemical noise (EN) technique, scanning kelvin probe force microscopy (SKPFM), scanning vibrating electrode technology (SVET) as well as by scanning electron microscopy (SEM) method. Wavelet analysis by EN technique and microscopic characterization showed that the galvanic corrosion process can be divided into five detail stages. SKPFM and SEM observations revealed that the B10 Cu-Ni alloy/2205 DSS is a small-scale B10/ferrite/austenitic galvanic corrosion system that reduces the resistance of 2205 DSS to pitting attack.
10.1016-j.corsci.2023.111617	2	corrosion; surface; film; electrochemical; films; spectroscopy; layer; current; solution; potential; resistance; composition; x-ray; ions; showed	The proposed study aimed to examine the impact of stress on the microbiologically influenced corrosion (MIC) behavior of a 90/10 copper-nickel (Cu-Ni) alloy using a self-made three-point bending device in the Desulfovibrio vulgaris inoculation system. The corrosion rate of alloy under plastic deformation was higher compared to elastic deformation, leading to the initiation of more severe cracks as well as the emergence of numerous secondary cracks at the bottom of the primary cracks. The stress played a vital role in strengthening the alloy's MIC process. A comprehensive mechanism for stress-assisted 90/10 Cu-Ni alloy MIC by D. vulgaris was proposed.
10.1016-j.corsci.2023.111637	-1		The oxidation behavior of Cu-Fe-based immiscible alloy produced by laser powder bed fusion at 500(degrees)C similar to 700(degrees)C were analyzed. The results show that the Cu-, Fe-, and Cr-rich oxide layers with the sandwich-like structure can be formed after the oxidation of different temperatures. In particular, after the oxidation for 10 h and 100 h at 500(degrees)C and 600(degrees)C, the island-like CuO were formed on the surface of alloy. However, CuO layer formed at 700(degrees)C was continuous and severely wrinkled so that the internal stress and the strength loss led to fracture of the oxide scales.
10.1016-j.corsci.2023.111671	2	corrosion; surface; film; electrochemical; films; spectroscopy; layer; current; solution; potential; resistance; composition; x-ray; ions; showed	The corrosion resistance of Cu-Ni-based alloys depends on their Cu2O passivation film, and the effect of third element X is hardly characterized. The corrosion behavior and mechanisms of Cu-10Ni-X (Al, Fe, Mn, Cr, Sn, Ti, Zn) alloys in a 3.5% NaCl solution were systematically investigated combining DFT calculation and experiments. Both computational and experimental results revealed that except Ti, other elements could enhance the corrosion resistance of Cu2O passivation film, and the effect was ranked as Fe > Cr > Mn > Al > Sn > Zn. Based on DFT and experimental data, a corrosion behavior prediction model was established.
10.1016-j.corsci.2023.111716	2	corrosion; surface; film; electrochemical; films; spectroscopy; layer; current; solution; potential; resistance; composition; x-ray; ions; showed	The galvanic effect induced by partial coverage of corrosion products films is studied for 90/10 copper-nickel alloy in flowing NaCl solution using electrochemical and surface analytical methods, aiming at understanding the localized corrosion mechanism. The results show that small-area bare samples act as cathode with polarity reversal and anode after coupled to statically and dynamically pre-filmed samples for 240 h, respectively. The latter indicates higher localized corrosion risk, especially at high flow velocities of 3.3 m/s and 4.2 m/s. The localized corrosion mechanisms are explained based on evolution of corrosion products films during coupling.
10.1016-j.corsci.2024.111878	15	aging; strength; conductivity; electrical conductivity; electrical; mpa; treatment; strengthening; degrees; cu-; cold; precipitation; tensile strength; tensile; iacs	The novel processing strategies of non-isothermal ageing (NIA) combined with cold rolling are proposed in this study. Results indicate that the pre-deformation of 20% in pre-deformation and NIA technology is more conducive to improving the corrosion resistance. The NIA and cold rolling technology promotes intermittent precipitation of grain boundary precipitates and higher density of dislocation cells. Therefore, the alloy processed by NIA for 16 h followed by cold rolling represents superior corrosion resistance. Meanwhile, the alloy processed by NIA for 16 h followed by cold rolling presents higher yield strength than that of the alloy treated by predeformation and NIA for 16 h .
10.1016-j.corsci.2024.112040	2	corrosion; surface; film; electrochemical; films; spectroscopy; layer; current; solution; potential; resistance; composition; x-ray; ions; showed	70/30 copper-nickel alloy was manufactured by laser powder bed fusion (LPBF), followed by the comprehensive investigation on the relationship between its microstructures and mechanical properties as well as corrosion behavior. The results show that dislocation tangles at cellular boundaries can greatly contribute to its superior tensile properties than the commercial counterpart. In addition, the combination of dislocation tangles and nanoscale copper enrichment/nickel depletion directly leads to the heterogeneous film formation process during immersion in corrosive media. Moreover, experimental and computational results both suggest that exposed facets are another important role to determine the corrosion behavior of LPBF 70/30 copper-nickel alloy.
10.1016-j.corsci.2024.112047	2	corrosion; surface; film; electrochemical; films; spectroscopy; layer; current; solution; potential; resistance; composition; x-ray; ions; showed	The corrosion of wrought, electrodeposited, and cold spray deposited copper was electrochemically monitored for similar to 160 days in 3 M NaCl solution containing traces of sulfide under anoxic and Ar-purged conditions. Corroded specimens were analyzed using scanning electron microscopy and Raman and X-ray photoelectron/Auger spectroscopies. Under anoxic conditions, corrosion was supported by sulfide only and the rate decreased with time causing only minor damage. Under low oxygen conditions maintained by Ar-purging, the rate increased with time and significant damage was observed, attributed to oxy-sulfur species formation. These results suggest that oxy-sulfur species, not just sulfide, are required to cause intergranular corrosion.
10.1016-j.corsci.2024.112328	2	corrosion; surface; film; electrochemical; films; spectroscopy; layer; current; solution; potential; resistance; composition; x-ray; ions; showed	Three imidazole-based compounds (imidazole, 2-mercaptobenzimidazole, and 2-mercapto-1-methylbenzimidazole) were studied as corrosion inhibitors of Cu, Zn, and a family of Cu-xZn brass alloys (x = 10-40 wt%) in 3 wt% NaCl solution. The composition of inhibitor layers on the surface was studied using X-ray photoelectron and infrared spectroscopies. The molecular adsorption modes on Cu and Zn were modelled using densityfunctional theory (DFT) calculations. Mercapto-based inhibitors act as efficient inhibitors on all materials studied due to the formation of inhibitor layer through bonding with nitrogen and sulphur atoms. In contrast, imidazole is a moderate inhibitor for Zn, while it is much less efficient for Cu.
10.1016-j.corsci.2024.112414	2	corrosion; surface; film; electrochemical; films; spectroscopy; layer; current; solution; potential; resistance; composition; x-ray; ions; showed	A numerical model was proposed to investigate the corrosion behavior of Cu-Zn-Fe couple in near-neutral 3.5 wt% NaCl. Evolution of current density, pH and soluble corrosion products were simulated in one-dimensional scale. The model predicted acidification on Zn surface and alkalization on Cu and Fe surfaces. pH evolution is related to corrosion products distribution. Zn2+ is the dominant specie formed on the middle of Zn surface. Zn hydrolytes are preferentially formed above the resin. Above the cathode surfaces distant from Zn, the concentration of corrosion products remains as zero.
10.1016-j.corsci.2024.112491	2	corrosion; surface; film; electrochemical; films; spectroscopy; layer; current; solution; potential; resistance; composition; x-ray; ions; showed	Ammonia is emerging as a carbon-free fuel but its corrosive effect on metal engine components, particularly those made of copper and copper alloys, is a major concern to be addressed. Herein, typical corrosion inhibitors are investigated in the presence of NH3. 3 . They have been ranked experimentally based on their corrosion initiation time while the NH3 3 diffusion barrier through inhibitor films has been evaluated using molecular dynamics simulations using a classical force field that was tuned to improve the Cu/inhibitor interactions. The excellent agreement with experiments indicates that this simulation approach could allow for the screening of new corrosion inhibitors.
10.1016-j.corsci.2024.112565	-1		The effect of water vapor on oxidation behaviors of amorphous and crystalline Cu-Zr alloys has been comprehensively investigated. Compared with dry oxidation, water vapor retards the oxidation of amorphous Cu-Zr alloy by lowering internal ionic diffusion and leading to the formation of stable crystalline oxide layers. In contrast, water vapor accelerates the oxidation of crystalline Cu-Zr alloy 10 times by enhancing the activity and outward diffusion of Cu and promoting an unexpected synchronous oxidation of Zr and Cu. This study would change the perspective from focusing exclusively on the detrimental effect of water to considering its suppression on surface oxidation.
10.1016-j.corsci.2025.112715	2	corrosion; surface; film; electrochemical; films; spectroscopy; layer; current; solution; potential; resistance; composition; x-ray; ions; showed	The effect of temperature gradients on the structures and chemical compositions of corrosion products films on 70/30 Cu-Ni alloy in 3.5 % NaCl solution has been investigated. A novel dissolution-deposition model with convection parameters has been proposed. Zero gradient of temperature (ZGT) promoted a protective Cu2O layer with minimal Cu2(OH)3Cl. Negative gradient of temperature (NGT) resulted in a thinner Cu2O layer and a non- protective Cu2(OH)3Cl two-layer structure with worst corrosion resistance, while positive gradient of temperature (PGT) solely formed a thicker and more protective Cu2O layer. Additionally, the effect of temperature gradients on Ni enrichment has been analyzed.
10.1016-j.corsci.2025.112801	2	corrosion; surface; film; electrochemical; films; spectroscopy; layer; current; solution; potential; resistance; composition; x-ray; ions; showed	Damage to Cu corroded in sulfide-containing solutions was investigated using scanning electron microscopy and surface profilometry. For dilute sulfide solutions (< 5 x 10- 5 M), a thin, porous film was formed, and general corrosion to a depth of < 1 mu m observed. At a higher concentration (5 x 10- 4 M), a compact film was formed and micro-galvanic corrosion observed. With increasing exposure time at higher concentration, the extent of microgalvanic corrosion decreased in favor of general corrosion, as the aspect ratio of the locally corroded sites increased. This indicates that micro-galvanic corrosion will eventually be stifled and only rough general corrosion observed.
10.1016-j.corsci.2025.112802	2	corrosion; surface; film; electrochemical; films; spectroscopy; layer; current; solution; potential; resistance; composition; x-ray; ions; showed	The susceptibility of 90/10 Cu-Ni alloy to crevice corrosion induced by Desulfovibrio vulgaris was investigated using a custom-designed crevice structure device under varying media conditions. There was no crevice corrosion in 20 % carbon source (CS) medium inoculated with D. vulgaris, whereas noticeable crevice corrosion occurred in 100 % CS D. vulgaris medium. The uneven distribution of D. vulgaris biofilms between the crevice interior and exterior resulted in localized variations in cathodic species concentration and electrochemical potentials, identified as key factors driving and accelerating crevice corrosion. The deceleration of crevice corrosion in the later stages was attributed to a decline in electrochemical driving force, likely caused by the diminished metabolic activity of D. vulgaris.
10.1016-j.corsci.2025.112894	-1		Effect of heat-treatment processes on the microstructure, corrosion and tribo-corrosion behavior of laser powder bed fusion (LPBF) Cu-15Ni-8Sn alloy were systematically investigated. The results demonstrate that the typical molten pool structures were destroyed after solid solution treatment. In contrast, aging process could facilitate the formation of spinodal decomposition structure, which significantly improves the hardness and tribocorrosion resistance of the LPBF alloy. Nevertheless, a prolonged aging could inversely aggravate the segregation and precipitation of Sn-rich phase along the cellular and grain boundaries, thus driving a severer micro galvanic effect to deteriorate its corrosion resistance. What's more, the prosperity of soft precipitates would further weaken the tribo-corrosion performance.
10.1016-j.corsci.2025.113181	14	strength; properties; conductivity; electrical; mechanical; cu-; grain; mpa; electrical conductivity; aging; precipitation; phase; mechanical properties; tensile; phases	It is conventionally believed that discontinuous precipitation exacerbates alloy corrosion, but its corrosion behavior remains unclear. This work investigates the influence of discontinuous precipitation on the corrosion behavior of a Cu-5.0Ni-1.2Si alloy through microstructural characterization and electrochemical testing. The results demonstrate that fibrous delta-Ni2Si discontinuous precipitation forms after 4 h of aging at 450(degrees)C, occupies approximately half of the microstructure by 8 h, and nearly fully dominates the alloy after 12 h . The corrosion resistance ranks as follows: 12 h (0.163 mm & sdot;a(-1)) > 4 h (0.169 mm & sdot;a(-1)) > 8 h (0.182 mm & sdot;a(-1)). During the initial corrosion stage, discontinuous precipitation accelerates Cu2O formation, promoting faster and thicker growth of the corrosion product film. In later stages, the larger dimensions of discontinuous precipitation enable it to act as reinforcing bars and firewalls within the film, inhibiting crack propagation and spallation, which has an unexpected contribution to the corrosion resistance of the alloy.
10.1016-j.corsci.2025.113405	2	corrosion; surface; film; electrochemical; films; spectroscopy; layer; current; solution; potential; resistance; composition; x-ray; ions; showed	The structural evolution of corrosion product films and the associated mechanism of corrosion resistance change in a 70/30 Cu-Ni alloy were investigated using a combination of multi-scale characterization and in situ electrochemical analysis. The results show that the increase in corrosion resistance during the growth of the corrosion product film is attributed to the synergistic effect of Cu and Ni. First, the transformation of the outer Cu2O layer from crystalline to amorphous/nanocrystalline structure enhances the resistance of the film to the penetration of aggressive ions. Second, Ni diffuse from the inner layer to the outer layer, doping into the Cu2O lattice and substituting Cu in Cu2(OH)3Cl. This reduces electrical conductivity and enhances the stability of the lattice structure, with DFT calculations providing validation for these effects. These processes enhance the corrosion resistance and stability of the film. The final mature corrosion product film in the static immersion state consists of three layers: the outermost layer of Cu2(OH)3Cl, the intermediate Cu-rich layer containing Nidoped Cu2O, Cu2(OH)3Cl and (Cu, Ni)2(OH)3Cl, the inner Ni-rich layer comprising amorphous and nanocrystalline NiO/Ni(OH)2, Cu2O, and minor iron oxides.
10.1016-j.cplett.2008.12.100	-1		When a glassy alloy Cu60.6Zr29.4Ti10.0 ribbon was immersed in weak acid HF solution at room-temperature, selective complete leaching out of the Zr and Ti elements occurred, resulting in the formation of a self-organized crystalline copper ribbon with grain size of 32 nm, by accelerated self-diffusion of Cu. Since the glassy alloy is formed by spd hybridization bonding, based on a combination of valence electrons (Eg) that exceeds the electrons (Ec) predicted by crystalline metallic bond theory, disappearance of its extra valence electrons, i.e., Delta E (Eg-Ec = 0.24 eV) for copper, due to leach-out of the Zr and Ti elements,we facilitates on crystallization of the copper agglomerate.
10.1016-j.cplett.2011.04.100	2	corrosion; surface; film; electrochemical; films; spectroscopy; layer; current; solution; potential; resistance; composition; x-ray; ions; showed	The corrosion behavior of copper-nickel-tin alloy in seawater with and without SRB has been tested by electrochemical techniques, SEM micrographs and EDX spectra. The geometric and electronic structure and active sites of Cu-n, Cun-1Ni and Cun-1Sn (n <= 9) clusters have been studied using DFT. The results indicated nickel and tin preferred to be the surface or outer layer in copper alloy, formed an oxide film on surface, then alloy would be corroded to Cu2O mostly after immersion. The corrosion process was accelerated in the presence of SRB, the mainly corrosion product was Cu2S, which was less protective for alloy.
10.1016-j.cryogenics.2006.06.002	9	magnetic; magnetization; magnetoresistance; temperature; superparamagnetic; annealing; gmr; field; magnetic properties; ferromagnetic; granular; samples; magnetic field; melt-spun; particles	The resistance of cold worked Cu-x wt%Ag alloys (x = 7 and x = 24) is measured in dependence of magnetic field and temperature. The magnetoresistance (MR) in the field range 0 T <= B <= 50 T is positive and increases with magnetic field. If the magnetic field B is applied perpendicular to the transport current I, the magnetoresistance increases in the temperature range from 77 K to 300 K. The highest value of 14% for the MR is measured at 77 K and 50 T. For I parallel to B it was found that the MR is independent of the temperature in the investigated range from 77 K to 199 K. The MR is attributed to the microstructure of the alloys and appears to be independent of the Ag content of the alloys under investigation.
10.1016-j.cryogenics.2018.01.010	-1		A comprehensive study has been carried out in relation to the conductivity of heavily deformed Cu-16wt%Nb nanostructured wires at room and cryogenic temperatures. When the true strain exceeds 5, the growth rates of the resistivity qualitatively change the behavior at all temperatures. It is shown that such behavior is defined mostly by interface scattering. At 10 K the stepwise increasing of resistivity has been found, what is speculated as a feature of amorphous regions formation at the interface of Cu/Nb. Simultaneously the superconducting transition temperature (T-cs) falls down due to proximity effect. The deviation of experimental T-cs values from predicted by classical model is discussed.
10.1016-j.cryogenics.2019.03.007	-1		Cryogenic conditions are new and promising environment for non-conventional copper base metal forming processing. Significant increase of ultimate tensile strength of copper and selected copper alloys during cryogenic wire drawing process is observed, but knowledge about technological aspects of the process is poor. The research paper presents the analysis of components limiting of cryogenic wire drawing forces and impact of the zinc addition on macroscopic properties of the wires obtained in the single-stage cryogenic drawing process. As part of the experimental research fine copper and Cu-Zn wires with 2.5 wt% and 6.5 wt% of zinc were produced by melting of fine metals in graphite crucibles using the induction furnace and casting it into steel moulds, its drawing and annealing. The research included wire drawing process conducted both at the ambient temperature and at the liquid nitrogen. Surface roughness test, mechanical properties tests (Brinell hardness, uniaxial tensile test) and physical properties test (resistivity) of wires were made. The significant effect of friction coefficient on wire drawing force under cryogenic condition was shown and the increase of the ultimate tensile test and hardness value of the Cu-Zn wires in comparison with the wires obtained at the ambient temperature has been observed.
10.1016-j.culher.2021.09.011	2	corrosion; surface; film; electrochemical; films; spectroscopy; layer; current; solution; potential; resistance; composition; x-ray; ions; showed	alpha/beta bronze bells are heritage materials subject to corrosion. The alteration of a high-tin bronze bell casted in the 1930s and exposed to a marine environment in a steeple was studied. The ternary bronze (Cu-Sn-Pb) alloy displays inclusions and a porosity due to micro-shrinkages and poor gas evacuation. This altered bronze is characterized to (1) assess the influence of the manufacturing techniques and (2) hypothesize a micro-infiltration scenario of its alteration. After exposure to the atmosphere, a transformed superficial medium overlaying layers of atacamite-paratacamite-cassiterite appears. Under them, the corrosion of the alpha dendritic structure and alpha/beta eutectoid characteristic of bronze bell is evidenced. The alpha pitting has a pronounced multilayered structure of cassiterite and cuprite-copper chloride, whereas the 8 corrosion is composed of cassiterite and traces of cuprite. To understand better the lead impact on corrosion process, samples of the alloy were exposed in the laboratory to a synthetic marine solution. The long-term corrosion behavior of the studied bell shows some similarities to those of other high tin bronze artefacts. The hypothesis of a corrosion scenario emphasizes the importance of the bells manufacturing techniques, alpha/beta structure of the ternary Cu-Sn-Pb alloy, and infiltrating networks of environmental fluids.
10.1016-j.desal.2019.114283	2	corrosion; surface; film; electrochemical; films; spectroscopy; layer; current; solution; potential; resistance; composition; x-ray; ions; showed	A benzimidazole derivative, 2-(2-bromophenyl)-1-methyl-1H-benzimidazole (2BPB) has been studied as a corrosion inhibitor for Cu-Ni 70/30 and 90/10 alloys in 1 mol/dm(3) HCl solution at low and high temperatures using the weight loss, electrochemical (potentiodynamic polarization (PDP), electrochemical impedance spectroscopy (EIS), & cyclic voltammetry (CV)), and surface characterization (scanning electron microscopy (SEM) & Fourier-transform infrared spectroscopy (FTIR)) techniques. The effect of immersion time (up to 72 h) and addition of iodide ions on the inhibition efficiency of 2BPB have also been investigated. At low temperature, 1.0 g/L 2BPB inhibits Cu-Ni 70/30 and 90/10 alloys by 88.9 +/- 4.8% and 57.5 +/- 1.3%, respectively. The performance of 2BPB improves with increase in immersion time and addition of iodide ions but slightly depreciates with rise in temperature. 2BPB acts as a mixed type corrosion inhibitor and adsorbs on the alloys surfaces through physical adsorption mechanism. SEM and FTIR results confirm the adsorption of 2BPB on the alloys surfaces. 2BPB is a potential low toxic candidate for the formulation of acid corrosion inhibitor for Cu-Ni alloys.
10.1016-j.diamond.2017.03.012	-1		Carbon nanotube reinforced copper alloy (CNT/Cu) composites with high strength and good wear resistance have been developed using acid treatment, sintering processes and consolidation techniques. The effects of CNT reinforcement and grain size refinement on the mechanical properties and surface deformations of CNT/Cu composite coatings are investigated by means of nanoindentation and block-on-ring wear tests, respectively. High-resolution transmission electron microscopy (HRTEM), scanning electron microscopy (SEM) and energy dispersive spectroscopy (EDS) analyses reveal that the CNTs are firmly implanted in the Cu alloy due to the formation of Cu-oxides at the CNT-Cu interface. The effect of CNT addition on the CNT/Cu coating strength is significantly greater than that of grain size reinforcement. Finally, the present results indicate that the addition of CNTs to the Cu matrix reduces the surface deformations of the CNT/Cu composite coatings due to the formation of a carbonaceous solid-lubricant film at the contact interface during sliding.
10.1016-j.diamond.2020.107912	-1		In this study, carbon nanotubes (CNTs) reinforced Cu-8.3Al matrix composites with different volume fractions of CNTs (0, 0.5, 1, 2 vol%) were produced by spark plasma sintering and hot rolling. The effects of carbon nanotubes on the microstructure, electrical conductivity and dry sliding wear behavior of the Cu-8.3Al alloy were studied. The addition of CNTs increased the electrical conductivity of Cu-8.3Al alloy. The composite with 1 vol% CNTs exhibited the best electrical conductivity in this work. Besides, under dry reciprocating sliding condition, the addition of a low volume fraction of CNTs (0.5 vol%) can improve the frictional properties of composites. Increasing the volume fraction of CNTs to higher values leads to fatigue wear and deterioration of the frictional properties. This study shows that by adding CNTs, the frictional and electrical properties of Cu-8.3Al alloy can be improved, which provides scientific guidance for the practical application of Cu-Al/CNTs composites.
10.1016-j.diamond.2020.108025	-1		A Cu-Ni-Sn matrix reinforced by Al2O3 particles (referred as CuNiSn/Al2O3) has been developed as a potential substitute for cobalt to fabricate diamond-cutting tools. CuNiSn/Al2O3 powder was first prepared through high energy ball milling, which was consolidated by hot pressing at 880 degrees C to a virtually pore-free matrix and diamond tools containing 10 vol% diamond grits separately. For comparison, a cobalt matrix and cobalt diamond tools were also prepared. The friction and wear behaviors of the matrixes and the diamond tools were investigated against ZrO2 balls under dry sliding in air on a ball-on-disk tester. The hardness, bending strength and bending elastic modulus of the CuNiSn/Al2O3 matrix are 99 HRB, 1308 MPa and 75.6 GPa, respectively, which are close to those of the cobalt matrix. However, the CuNiSn/Al2O3 matrix exhibits a more stable friction coefficient and higher wear resistance than the cobalt matrix, and ZrO2 can be more effectively grinded off by CuNiSn/Al2O3 diamond tools than cobalt diamond tools. With detailed microstructural analyses, the possible friction and wear mechanism are discussed. The new CuNiSn/Al(2)O(3 )matrix is promising for fabricating diamond tools with low cost, high processing efficiency and long service life.
10.1016-j.diamond.2021.108600	-1		In this study, carbon nanotubes (CNTs) reinforced Cu-Al based composite materials were prepared by powder metallurgy. Al powders were mechanically mixed with Cu powders. Al diffused under high temperature sintering to strengthen the matrix via alloying with Cu and forming a transition interface between CNTs and Cu to improve the interfacial bonding. The microstructure and tensile properties of the Cu-Al/CNTs composites were characterized. The effects of the addition of CNTs, Al alloying and hot rolling processing on the microstructure and properties of the composites were analyzed. The results indicate that after spark plasma sintering and hot rolling, the tensile strength and yield strength of the Cu-1Al/0.5 vol% CNTs composite reached 34.0% and 100% higher than that of the Cu/0.5 vol% CNTs composite without Al addition, and an elongation of 41% was still maintained.
10.1016-j.diamond.2022.108926	17	wear; composites; coating; friction; composite; coatings; surface; tribological; properties; wear resistance; resistance; powder; sliding; matrix; wear rate	Cu-Sn-Ti filler is commonly used in industrial production to prepare diamond tools. However, the hardness and strength of the Cu-based brazing filler metal are low, resulting in poor wear resistance of the brazing filler metal. In this work, novel brazed diamond segments were fabricated using Cu-Sn-Ti-xB4C composite fillers. The correlation between the interfacial compounds and friction and wear performance was studied. The results showed that after adding B4C with 2 wt%, B4C can react with the Cu-Sn-Ti filler, which moderates the wetting reaction between the active alloy and the diamond particles during brazing. The exposure of diamond was high and no obvious thermal damage occurred. The layered compounds is formed on the interface of the diamond; the SEM and XRD characterization prove that the compounds generated on the diamond surface is TiC. Vickers hardness tester was used to measure the microhardness of the fillers layer and the interface layer, and the hardness value of the filler layer gradually increased with the increase of B4C content. When the addition of B4C is 2%, the hardness value of the interfacial layer reaches 255 HV0.05. The friction and wear experiments results showed that when B4C was added at 2%, the wear material removal was 0.189 g and the wear resistance of the brazed specimens was optimal.
10.1016-j.diamond.2022.109110	-1		New brazed diamond specimens were prepared by adding different types of rare earth (RE) alloys to Cu-Sn-Ti filler metal. The microstructure and mechanical properties of the filler metal were characterized, and the interfacial characteristics and grinding properties of the brazed diamond specimens were analyzed. The addition of rare earth alloy (10% Cu-La alloy, 10% Cu-Ce alloy, and 10% Cu-Nd alloy) can improve the microstructure of the filler metal, reduce the number and size of holes and cracks in the filler metal, and improve the mechanical properties of the filler metal. The results of the grinding tests showed that the addition of the three rare earth alloys could improve the holding strength of the filler metal on the diamond grains, reduce the shedding rate of the diamond grains, and improve the grinding performance of the brazed diamond specimens. Compared with the other two rare earth alloys, the addition of 10% Cu-Nd improves the mechanical properties of the filler metal most significantly, and the best grinding performance of brazed diamond samples is obtained because there is no composite undercooling and aggregation of rare earth elements. The mechanism of rare earth alloy to improve the holding strength of filler metal to diamond abrasive grains was elucidated that the rare earth elements consume Cu and Sn elements in the filler metal, and the enrichment of Ti elements at the interface increases the thickness of the TiC interfacial layer. In addition, the reduction of cracks and holes in the filler metal decreased the defects around the diamond of the brazed specimen, effectively avoiding the rapid expansion of cracks along with these defects during the grinding process.
10.1016-j.diamond.2023.109973	-1		In the study high-energy ball milling was employed to fabricate Cu-Cr-Nb /graphite composites through the powder metallurgy method. Cu-Cr-Nb powders mixed with flake graphite were milled together and combined with various concentrations of Cu-10Sn by continuous high-energy ball milling. Rapid hot press sintering was applied to create Cu-Cr-Nb/graphite/Sn composites. In situ carbide production and alloying elements in Cu-Cr-Nb alloys were employed to enhance the material's characteristics. The composites' mechanical properties and softening temperature were characterized. Results indicated a speckled C solid solution in the composite Cu-Cr-Nb/graphite powders. The Cu-Cr-Nb/graphite composites produced in this experiment had a density of >99 %, a hardness of 94 HV, a friction coefficient of 0.12 (the load of 10 N), a compressive yield strength of 185.4 MPa, and a high-temperature softening resistance of 900 degrees C. To generate carbide, the composites were significantly enriched in Cr and C toward the boundary. The Cr precipitates and the trace of Cr-carbides not only increased mechanical properties but also hindered recrystallization and grain growth, enhancing the softening temperature.
10.1016-j.diamond.2023.110068	17	wear; composites; coating; friction; composite; coatings; surface; tribological; properties; wear resistance; resistance; powder; sliding; matrix; wear rate	In the brazed joints prepared by Cu-Sn-Ti filler metal, it was found that the filler metal has poor wettability to diamond and diamond abrasive grits are prone to uneven wear resulting in low efficiency of diamond tools and difficulty in achieving the expected processing which are the key factors restricting the performance of brazed diamond tools with Cu based filler. This study aims to improve the wettability of Cu-Sn-Ti filler metal and the brazed joint wear resistance. For this purpose, a new Cu-Sn-Ti-Ga-In composite filler metal was proposed. In this experiment, the subcooling degree and microstructure morphology of the new filler metal were investigated, the microhardness and shear strength of the filler metal were determined, and the shear fracture morphology was analyzed. Wetting tests were conducted on graphite plates to study the effect of indium elements on the wettability of the filler metals. Brazed joints were also prepared, and the crawling morphology of the filler metal on the diamond surface and the wear marks of the diamond abrasive after the frictional wear test were observed. The test results show that Sn3Ti5 is a solid solution is favorable to explain some phenomena. The indium element can increase the subcooling of the filler metal, thus promoting the refinement of Sn3Ti5, and the formation of eutectic microstructure. In brazed joints, indium increases the wettability of the filler metal on the diamond surface thus increasing the climb height and reducing the uneven wear rate, and the brazed joints have the best cutting performance when the filler metal is added with 1 wt% of indium element.
10.1016-j.diamond.2024.111113	14	strength; properties; conductivity; electrical; mechanical; cu-; grain; mpa; electrical conductivity; aging; precipitation; phase; mechanical properties; tensile; phases	This study presents a comprehensive investigation of copper-based nanocomposites reinforced with silicon carbide (SiC) nanoparticles and multi-walled carbon nanotubes (MWCNTs). The manufacturing procedure involved powder metallurgy techniques followed by spark plasma sintering (SPS). Microstructural analysis revealed a notable reduction in particle size (from 23.72 mu m to 18.31 mu m) and crystallite size (from 104.32 nm to 87.36 nm) with the addition of reinforcements. The bulk microstructure exhibited a reduction in grain size by approximately 13.1 %. XRD analysis confirmed the absence of new phases. Evaluation of SPS parameters demonstrated varying density and porosity, with the highest relative density of 99.96 % observed in pure copper composites. Hardness measurements indicated that surface hardness surpassed cross-sectional values, with the lowest recorded value being 64.79 HV for composite Cu-5%SiC-1%MWCNTs (S4). Wear rate analysis revealed an increase, with pure copper composites exhibiting a wear rate of 1.78 x 10-4 mm3/m, while composite S4 displayed a rate of 3.25 x 10-4 mm3/m under a load of 5 N. Coefficient of Friction (COF) exhibited significant fluctuations, influenced by the applied load and composite composition. Thermal conductivity decreased with higher SiC and MWCNT content, with sample S1 exhibiting the highest thermal conductivity among reinforced composites. Electrical conductivity trends were influenced by the type and concentration of reinforcing particles, resulting in an increase of approximately six times in composite S4 compared to the pure sample.
10.1016-j.diamond.2024.111290	14	strength; properties; conductivity; electrical; mechanical; cu-; grain; mpa; electrical conductivity; aging; precipitation; phase; mechanical properties; tensile; phases	Cubic boron nitride (cBN) grits were joined with a Cu70-Sn20-Ti10 solder alloy powder at a temperature of 960 degrees C for 20 min under vacuum. The bonding morphology, macroscopically and microscopically, was analyzed, along with the interfacial reaction layer products and thickness of Cu-Sn-Ti/cBN grits. The research extensively characterized the surface morphology and attachment phase of cBN grits both before and after a reaction process. The analysis also included a detailed examination of the cBN grits' morphology. Moreover, the research performed a comparative evaluation of the compressive strength of cBN before and after the reaction, providing valuable insights into the effect of the reaction process on cBN's mechanical properties. The results indicate that the solder effectively wets the surface of the cBN grits, demonstrating good wettability. At the microscopic level, the reaction layer with a structural sequence of cBN-TiB2-TiB-TiN forms at the interface between the two materials. This reaction layer is approximately 5.65 mu m thick and exhibits a chemical metallurgical combination. Moreover, the compressive strength of cBN remained unchanged before and after brazing.
10.1016-j.diamond.2024.111667	14	strength; properties; conductivity; electrical; mechanical; cu-; grain; mpa; electrical conductivity; aging; precipitation; phase; mechanical properties; tensile; phases	Copper and its alloys are well-known for their excellent electrical and thermal conductivity but are limited by poor mechanical strength and wear resistance. In this study, CuSn19Ti10/diamond composite coatings with strong metallurgical bonding and free from defects such as cracks and porosity were successfully fabricated on pure copper substrates using laser cladding. The process parameters included a laser power of 3000 W, a scanning rate of 15 mm/s, a spot diameter of 2.5 mm, and a lapping rate of 30 %. A comprehensive analysis of the microstructure and wear resistance was performed on coatings with 0, 2.5 %, 5 %, and 10 % (wt%) diamond content using SEM, EDS, XRD, and white light interferometry. The results indicate that the coatings consist of alpha-(Cu), Cu2SnTi, (Cu, Sn)Ti2, TiC, and diamond phases. The addition of diamond significantly improved both the hardness and wear resistance, with the 5 wt% diamond composite demonstrating the most notable wear resistance. This optimal composition balances diamond content, ensuring effective retention within the CuSn19Ti10 matrix, thereby reducing plastic deformation and minimizing diamond pull-out during wear.
10.1016-j.dt.2023.02.018	-1		In this work, a Cu-10Ta alloy with a copper to tantalum mass ratio of 9:1 is prepared using powder metallurgy technology. Physical properties of the alloy, including density, microstructure, melting point, and constant-volume specific heat, are tested. Via the split Hopkinson pressure bar (SHPB) and flyerplate impact experiments, the relationship between equivalent stress and equivalent plastic strain of the material is studied at temperatures of 298-823 K and under strain rates of 1 x 10-3-5.2 x 103 s-1, and the Hugoniot relationship at impact pressures of 1.46-17.25 GPa and impact velocities of 108 -942 m/s is obtained. Evolution of the Cu-10Ta microstructure that occurs during high-strain-rate impact is analyzed. Results indicate that the Cu-10Ta alloy possesses good thermal stability, and at ambient temperatures of up to 50% its melting point, stress softening of less than 15% of the initial strength is observed. A modified J-C constitutive model is employed to accurately predict the variation of yield strength with strain rate. Under strong impact, the copper phase is identified as the primary source of plastic deformation in the Cu-10Ta alloy, while significant deformation of the high-strength tantalum particles is less pronounced. Furthermore, the longitudinal wave speed D is found to correlate linearly with the particle velocity u upon strong impact. Analysis reveals that the sound speed and spallation strength of the alloy increase with increasing impact pressure. (c) 2024 China Ordnance Society. Publishing services by Elsevier B.V. on behalf of KeAi Communications Co. Ltd. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/ licenses/by-nc-nd/4.0/).
10.1016-j.elecom.2011.06.015	2	corrosion; surface; film; electrochemical; films; spectroscopy; layer; current; solution; potential; resistance; composition; x-ray; ions; showed	High aspect ratio Cu-rich Cu-Ni microcolumns have been fabricated on brass substrates by Localized Electrochemical Deposition using a platinum microanode with an electrical bias of 7.0 V. Sulfate-citrate baths with and without the presence of saccharine as a grain-refining agent, have been used. The microcolumns are similar to 100 mu m in diameter and several hundreds of micrometers in height. The addition of saccharine to the electrolytic solution resulted in the reduction of both the porosity and the surface roughness of the Cu-Ni grains in the microcolumns. The Ni/Cu atomic ratio on the top of the microcolumns was higher than that at the bottom, indicating a composition gradient along the height of the columns. Despite their relatively low Ni content (below 35 at% in all cases), the microcolumns were weakly ferromagnetic. Nanoindentation hardness and reduced Young's modulus were also measured. Larger values of both parameters were obtained in the columns grown in the presence of saccharine.
10.1016-j.elecom.2024.107734	-1		To assess the corrosion resistance of Cu-Fe deformation in situ alloys in a chloride ion environment, Cu-Fe alloys with varying Fe contents (5 wt%, 10 wt%, and 14 wt%) were prepared using vacuum induction melting, and the impact of Fe content on the corrosion resistance was examined. The corrosion morphology and corrosion products were analyzed, and the corrosion rate, corrosion period, dynamic potential polarization curves, electrochemical parameters, and electrochemical impedance spectra with different Fe contents were determined. However, the corrosion resistance of Cu-Fe alloys initially increased with an increase in Fe content before decreasing, with Cu-10 wt% Fe alloys (95% reduction rate) exhibiting the best corrosion resistance. As the Fe content increased, the amount of primary Fe phase gradually increased and became more densely distributed. This led to an increase in the dense oxide film on the surface, thereby enhancing the corrosion resistance of the material. Moreover, with a further increase in Fe, the primary Fe phase exhibited coarsening and non-uniform distribution. This resulted in the oxide film becoming looser, leading to a decreased corrosion resistance of the alloy.
10.1016-j.electacta.2004.01.038	2	corrosion; surface; film; electrochemical; films; spectroscopy; layer; current; solution; potential; resistance; composition; x-ray; ions; showed	The corrosion of Cu-30Ni in presence of 3-amino-1,2,4-triazole (ATA) was examined in 3% NaCl solution containing ammoniac. For the cathodic processes, the addition of ATA slows down markedly the reduction reaction of dissolved oxygen, and the cathodic process is controlled merely by the hydrogen evolution. Besides, ATA inhibits efficiently the hydrogen evolution itself when the kinetics parameters were evaluated from a non-linear regression calculation according to Levich-Koutecky relationship. For the anodic processes, the addition of ATA suppressed completely the current peak observed at the active-passive transition revealed in its absence, and the passive current plateau is observed directly from the corrosion potential. Therefore, the addition of ATA reduces both the anodic and the cathodic partial currents of the corrosion process. The inhibiting efficiency of ATA is high, more than 98%, and even enhanced in presence of ammoniac. It was found also that this inhibiting effect increased with the immersion period.
10.1016-j.electacta.2004.06.027	2	corrosion; surface; film; electrochemical; films; spectroscopy; layer; current; solution; potential; resistance; composition; x-ray; ions; showed	The electrochemical behavior of brasses with various Zn content (5.5-38 mass%) and brass (Cu-38Zn) with different Ph contents (1-3.4 mass%) in 0.6 M NaCl was investigated. The effects of temperature, immersion time, and concentration of chloride ions on the behavior of the different alloys were studied. The pitting corrosion behavior of Cu-Zn alloys and leaded-brass alloys in 0.6 M NaCl solution was also investigated. Open-circuit potential measurements (OCP), polarization techniques and electrochemical impedance spectroscopy (EIS) were used. The results show that the increase in the Zn content increases the corrosion rate of the brass alloys in chloride solutions, while the increase of Ph content in Cu-38Zn-Pb decreases the corrosion rate of the alloy. Long immersion time of the alloys in the aqueous electrolyte improves their stability due to the formation of passive film on the alloy surface. The breakdown potential is shifted to more negative direction with increasing the Zn content, whereas it shifts towards positive values with increasing Pb content. Equivalent circuit model for the electrode/electrolyte interface under different conditions was proposed to illustrate the electrochemical processes taking place at the interface. The electrochemical behavior of the different alloys was discussed in view of the fitting results. (C) 2004 Elsevier Ltd. All. rights reserved.
10.1016-j.electacta.2004.11.033	2	corrosion; surface; film; electrochemical; films; spectroscopy; layer; current; solution; potential; resistance; composition; x-ray; ions; showed	The electrodeposition of ternary Cu-Ni-Zn and Cu-Ni-Cd alloys was investigated in acidic sulphate electrolytes. The influence of Zn2+ and Cd2+ ions concentrations as well as the effect of current density on the surface appearance and the deposits' composition was examined. Sodium dithiolate (NaS)(2)C = C(CN)(2)-3H(2)O was used as surface active substance (SAS), and the effect of the SAS on the alloys composition and surface morphology was also investigated. No significant effect of SAS on the alloy composition, however, apparently effect on the deposits surface morphology was observed. It was also noticed that on increasing Zn2+ (or Cd2+) concentration in the bath, a depletion in the nickel content in the deposit occurred. Deposits obtained were characterized from the structural and morphological points of view. It was found that the structure and morphology of the deposited alloys are mainly controlled by both the applied current densities and the bath composition. (c) 2004 Published by Elsevier Ltd.
10.1016-j.electacta.2005.10.035	11	glass; bulk; metallic; bulk metallic; gfa; bmg; glassy; metallic glass; ability; bulk metallic glass; amorphous; addition; crystallization; mm; glass-forming	(Cu47Zr11Ti34Ni8)(100-x)Mo-x bulk metallic glasses (BMGs) with x = 0, 1 and 2 at. % and a bulk metallic glass matrix composite with x = 5 at% were successfully prepared by water-cooled copper mold casting. The effect of the addition of a small amount of Mo on the glass forming ability (GFA), thermal properties of the base alloy (i.e. x = 0) were investigated by X-ray diffraction (XRD), differential scanning calorimetry (PSC) and differential thermal analyzer (DTA). It is found that the addition of appropriate amount of Mo can enhance the GFA of the Cu-based BMG, as indicated by the increase in the reduced glass transition temperature T-rg (=T-g/T-l) and the parameter gamma (=T-x(T-g + T-l)) with the increase of Mo. On the other hand, the corrosion resistance of the Cu-based BMGs with different Mo contents was examined by electrochemical polarization and weight loss measurement in 1 mol/L H2SO4 and 1 mol/L NaOH solutions, respectively. It is found that the corrosion resistance of Cu-based BMGs increased with increasing Mo content with the lowest corrosion rate of (0.9 +/- 0.2) x 10(-3) mm/year in 1 mon H2SO4 solution and (0.3 +/- 0.1) x 10(-3) mm/year in 1 mol/L NaOH solution, respectively, for the BMG containing 2 at% Mo. X-ray photoelectron spectroscopy (XPS) results revealed that the improvement of corrosion resistance of Cu-based BMG containing appropriate amount of Mo originated from the enrichment of ZrO2 and TiO2, but depletion in Cu- or Ni-oxides in the passive films formed during electrochemical polarization. Finally, the galvanostatic-step measurement was performed to investigate the kinetics of the formation of passive films on the BMG surfaces. It is demonstrated that the addition of an appropriate amount of Mo can effectively improve the stability and uniformity of the passive film. The role of Mo addition on the glass forming ability and corrosion behavior is discussed.
10.1016-j.electacta.2006.05.047	-1		The corrosion behavior of the as-cast Cu-Zr alloys, with 15%, 30%, and 66% Zr (in at%) were investigated in 0.1 mol/l HCl solution. Results revealed that the Cu-15 Zr alloy has the lowest corrosion rate in the potential region of selective dissolution of Zr as the result of the low Zr content. The corrosion rate was remarkably increased when Zr increased from 15% to 30%. The corrosion rate of the Cu-66Zr alloy is close to that of the Cu-30Zr alloy. This illustrates that the Zr content has little effect on the selective dissolution rate of Zr when Zr arrives at a certain degree in Cu-Zr alloys. In the potential region of simultaneous dissolution of Cu and Zr, the corrosion rate at the higher anodic potential depends on the content of both Cu and Zr, and the Cu-30Zr alloy has the worst corrosion resistance.
10.1016-j.electacta.2006.06.029	2	corrosion; surface; film; electrochemical; films; spectroscopy; layer; current; solution; potential; resistance; composition; x-ray; ions; showed	Studies of the phase and chemical compositions as well as of the surface morphology of Cu-Sn alloys electrodeposited in the sulphate solution containing laprol were carried out using the XRD, SEM, and EDX techniques. The multiphase composition-pure copper, the alpha-CuSn phase and the intermediate hcp phase were determined to be present in the deposits obtained at cathode potentials positive to that of the reversible of the Sn/Sn2+ electrode. When the content of Sn in the deposit was higher than 12-13 at%, the beta and/or delta phases were determined to be present along with that mentioned above. The deposit obtained at the potentials negative to that of the reversible of the Sn/Sn2+ electrode presented the 8 phase with low quantities of the pure Cu and alpha-CuSn phases. The grain size of deposits increased with the cathode potential until it was positive to that of the reversible of the Sn/Sn2+ electrode. The presence of Br- ions in the solution hindered the granular electrocrystallization and reduced the Sn proportion in the alloy. It was assumed that underpotential deposition (UPD) of Sn on copper could be responsible for the formation of the multiphase composition and the intermediate hcp phase. It was concluded that the brightness of the studied Cu-Sn coatings was conditioned by the surface morphology.
10.1016-j.electacta.2006.07.050	2	corrosion; surface; film; electrochemical; films; spectroscopy; layer; current; solution; potential; resistance; composition; x-ray; ions; showed	The cyclic voltammetry and mixed potential behaviour of freshly polished UNS C70610 (CN 102) 90-10 copper-nickel has been examined in fully characterised seawaters using the rotating disc electrode (RDE) and the rotating cylinder electrode (RCE). Reynolds number dependent corrosion potentials are derived for a wide range of Reynolds numbers and good comparison is made with directly measured values. The films formed on initial exposure of the 90-10 copper-nickel alloy to the seawaters did not confer any additional protection relative to unalloyed copper. Indeed, the 90-10 copper-nickel tended to exhibit relatively high anodic and cathodic currents when directly compared to both unalloyed copper and a nickel aluminium bronze under identical conditions. The corrosion potential of the alloy becomes more negative at higher flow velocity, due to the influence of mass transport on the anodic reaction mechanism at potentials close to the mixed potential. Overall, the results indicate that the character of the freshly polished material/electrolyte interface has a much greater influence over the magnitude of the corrosion rate than the turbulence intensity of the fluid.
10.1016-j.electacta.2006.12.039	2	corrosion; surface; film; electrochemical; films; spectroscopy; layer; current; solution; potential; resistance; composition; x-ray; ions; showed	During the first 48 h that pure copper is submerged in a chloride containing solution, an oxide layer is formed that acts as a barrier layer between the aggressive solution and the substrate, offering some protection to the material. This barrier layer itself is subsequently attacked and localized corrosion is observed. The study of the corrosion behavior was based on open circuit potential (OCP) measurements. The evolution of this value was concurrent with the evolution of the state of the oxide layer. Furthermore the surface state was evaluated by taking impedance spectra every 2 h . This method proved to be insufficient to elucidate the surface evolution and additional techniques were employed. The thickness and the composition of the oxide layers as well as the different composition of the corrosion products in and around the zones of localized attack were determined by means of an FE-AES equipped with an ion gun. The scanning electron microscope (SEM) allowed us to visually discriminate between the three stages the surface passes through during the first 48 h . Mathematically the equivalent circuit used in literature fits the impedance data very well. The observations in this work are however in contradiction with the different physical meanings attributed to the circuit elements found in literature. Further research is necessary to reveal the real mechanism of copper corrosion in this sort of systems.
10.1016-j.electacta.2006.12.053	2	corrosion; surface; film; electrochemical; films; spectroscopy; layer; current; solution; potential; resistance; composition; x-ray; ions; showed	The present study concerns the chemical-physical and electrochemical characterizations of the corrosion compounds formed on outdoor bronzes exposed in urban conditions. Here, we focused on the pale green patinas of surfaces directly exposed to the rainfall leaching. The investigation has been per-formed from scraped-off patina products of a well representative outdoor bronze monument (Monument to Francis Gamier, 1898) situated in Paris (France). The composition of the patina was analysed by energy dispersive spectrometry (EDS), coupled with SEM, and Raman spectroscopy. Structural characterization was conducted through high-resolution TEM (EDS coupled). The electrochemical reactivity of patina was investigated by cyclic voltammetry and EIS with a microcavity electrode in sulphate solution at pH 2 and 5.6 with time of immersion (up to 10 h). The bronze patina corresponds to a two-layer structure. The external layer is characterised by a marked selective dissolution of Cu and Zn of the alloy. which has been determined from the calculation of dissolution factors. The same phenomenon with the same amplitude has been evidenced on other bronze monuments used for comparison. The pale green patina is a complex mixture of crystalline copper hydroxisulphate and of amorphous/nanocrystal Sn-containing compounds. This patina is stable at pH 5.6 and reactive at pH 2 in relation with the dissolution of copper sulphate compounds in the acidic solution.
10.1016-j.electacta.2008.05.081	2	corrosion; surface; film; electrochemical; films; spectroscopy; layer; current; solution; potential; resistance; composition; x-ray; ions; showed	The many equipment problems in recent years due to early failure of copper alloys in heat exchange plants have spurred tests aimed at monitoring and controlling the microbial-influenced corrosion (MIC) of these materials. The present work focused on the formation of protective oxide layers growing on CuNi 70/30 alloy, which is commonly employed in seawater-cooled plant systems. It documented the positive role of chlorination treatments. Measurements were carried out in plants and pilot circuits, under different sets of conditions. An integrated hardware system that includes both innovative electrochemical sensors and traditional probes and is driven by specific data acquisition software has been used for on-line monitoring of biofilm growth and corrosion processes on CuNi 70/30 specimens. This integrated system also allowed measurement of some physico-chemical parameters of the water (flow, temperature, turbidity, oxidants). Before and after their exposure to seawater, the alloy specimens were weighed and subjected to chemical and metallographic analyses. The results confirmed that brief chlorination treatments with 0.4-0.8 mg/l of residual-free oxidant for 0.5-1 h a few times a day promote the formation of a protective layer on the Cu-based alloy. This layer, if well established, is able to prevent localized corrosion even when the seawater become particularly aggressive, as happens when biofouling grows or mud is incoming.
10.1016-j.electacta.2009.03.040	2	corrosion; surface; film; electrochemical; films; spectroscopy; layer; current; solution; potential; resistance; composition; x-ray; ions; showed	The electrochemical behavior of the Cu-10Al-5Ni alloy in simulated electrolytes like those used in the industrial processes under normal working conditions was investigated. Conventional electrochemical techniques including open circuit potential measurements, polarization techniques, and electrochemical impedance spectroscopy were used. The alloy was found to be more stable against corrosion when the chloride-sulfate solution had a pH of 7-9. A sulfate concentration of congruent to 0.1 M in the chloride-sulfate electrolyte leads to the passivation of the alloy surface. The activation energy of the corrosion process was found to be 8 kJ mol(-1) assigning a diffusion controlled reaction. The impedance measurements and impedance data fitting to equivalent circuit models have shown that the passive film posses a duplex nature.
10.1016-j.electacta.2009.07.058	2	corrosion; surface; film; electrochemical; films; spectroscopy; layer; current; solution; potential; resistance; composition; x-ray; ions; showed	Surface oxide films were grown on 99.99% copper and brass (copper-zinc alloy. Cu77Zn21Al2) in 0.1 mol L-1 borax solution at open circuit potential and were characterized using various experimental techniques. The composition of the passive films formed in situ on the different materials was studied using differential reflectance spectroscopy. The thickness of the oxide layers on copper and brass was compared by chronopotentiometric curves and potentiodynamic reductions. The electrical properties of each oxide were analyzed by means of electrochemical impedance spectroscopy. Their influence on the oxygen reduction reaction was also investigated using voltammetry hydrodynamic tools such as the rotating disk electrode. The results show that the incorporation of Zn to Cu in brass changes the composition and the thickness of the surface film. The films grown on brass tend to be thicker but less resistive and Zn compounds incorporate to the film. This is supported by results from reflectance and impedance spectroscopy. The kinetics of oxygen reduction is strongly inhibited on oxidized electrodes, particularly in the case of brass. The global number of exchanged electrons remains close to four and seems to be independent of the presence of surface oxides.
10.1016-j.electacta.2010.09.080	2	corrosion; surface; film; electrochemical; films; spectroscopy; layer; current; solution; potential; resistance; composition; x-ray; ions; showed	The electrochemical behavior of Cu-Al-Ni alloys in chloride free neutral solutions was investigated. The effect of Ni content on the corrosion resistance of the alloys was examined and evaluated. Conventional electrochemical techniques and electrochemical impedance spectroscopy. EIS, have been used. Potentiodynamic measurements revealed that the increase in the Ni content decreases the stability of the Cu-Al-Ni alloys. The polarization measurements were confirmed by EIS experiments. The morphology of the alloy surface was investigated by scanning electron microscopy, SEM, and surface analysis was made by energy dispersive X-ray technique. The experimental impedance data were fitted to theoretical data according to a proposed equivalent circuit model representing the electrode/electrolyte interface. The results of these experiments are discussed in reference to the potential-pH (Pourbaix) diagrams of the alloying elements.
10.1016-j.electacta.2011.04.086	2	corrosion; surface; film; electrochemical; films; spectroscopy; layer; current; solution; potential; resistance; composition; x-ray; ions; showed	The mechanism of corrosion of oxygen-free copper has been studied in stagnant aqueous sulfide solutions using corrosion potential and electrochemical impedance spectroscopy (EIS) measurements. Film structure and composition were examined on surfaces and on cross-sections prepared by focused ion beam (FIB) milling using scanning electron microscopy (SEM) and energy dispersive X-ray spectroscopy (EDS). Experiments were conducted in anaerobic 5 x 10(-5) mol dm(-3) Na2S + 0.1 mol dm(-3) NaCl solutions for exposure periods up to 4000 h (similar to 167 days) to mimic (at least partially) the conditions that could develop on a copper nuclear fuel waste container in a deep geologic repository. The corrosion film formed was a single cellular Cu2S layer with a non-uniform thickness. The film thickness increased approximately linearly with immersion time, which implied that the sulfide film formed on the Cu surface is non-protective under these conditions up to this exposure time. The film growth process was controlled by HS- diffusion partially in the aqueous solution in the pores in the cellular sulfide film and partially in the bulk of the aqueous solution.
10.1016-j.electacta.2013.06.079	2	corrosion; surface; film; electrochemical; films; spectroscopy; layer; current; solution; potential; resistance; composition; x-ray; ions; showed	The corrosion inhibition efficiency of cysteine, N-acetylcysteine and methionine as environmentally safe materials for the corrosion of Cu-10Al-5Ni alloy in 3.5% NaCl solution was investigated. Different electrochemical techniques such as open circuit potential, potentiodynamic polarization measurements and electrochemical impedance spectroscopy, EIS, were used. Microstructure analysis and surface morphology were carried out using the suitable surface analytical techniques. Potentiodynamic polarization measurements showed that the presence of cysteine in chloride solutions affects mainly the cathodic process and decreases the corrosion current to a great extent and shifts the corrosion potential toward more negative values. Corrosion inhibition efficiency of about 96% could be achieved by the presence of 6.0 mM of cysteine in a simulated saline solution. The experimental impedance data were analyzed according to a proposed equivalent circuit model for the electrode/electrolyte interface. The corrosion inhibition process is based on the adsorption of the amino acid molecules on the alloy surface, and the adsorption follows the Langmuir adsorption isotherm. The free energy of adsorption of the different amino acids on the alloy surface was in the range of approximate to-35kJ mol(-1), which reveals a strong physical adsorption of the inhibitor molecules on the metallic surface.
10.1016-j.electacta.2013.06.140	2	corrosion; surface; film; electrochemical; films; spectroscopy; layer; current; solution; potential; resistance; composition; x-ray; ions; showed	The ionic liquid choline acetate was used as a cyanide-free electrolyte for the electrodeposition of copper-zinc alloy (alpha-brass) thin films on a steel substrate. In comparison with the more commonly used choline chloride based deep-eutectic solvents, choline acetate enables the electrodeposition in absence of chloride ions, in order to avoid their accelerating effect. With 0.1 mol dm(-3) Cu(OAc)(2)center dot H2O and 0.1 mol dm(-3) Zn(OAc)(2)center dot 2H(2)O dissolved in choline acetate, the reduction potentials of copper and zinc were separated by 500 mV. Using potentiostatic deposition, only coatings of a negligible thickness could be obtained. Upon addition of triethanolamine, the deposition rates of both copper and zinc increased substantially and the reduction potential of copper shifted 300 mV toward more cathodic potentials. Bright layers with a thickness of up to 200 nm could be obtained. With a 1:2 molar ratio of metal-to-triethanolamine, well-adherent mirror-bright deposits with a composition of 90 wt% Cu and 10 wt% Zn were deposited at -1.5 V versus Ag vertical bar AgCl (3M KCI), with a cathodic current efficiency of around 75%. For longer deposition times, morphological instabilities occurred. Addition of polyvinyl alcohol in concentrations between 8 and 20 mg dm(-3) enabled the deposition of mirror-bright brass layers with a thickness up to I mu m. Variation of the deposition potential between -1.3 and -1.5 V had no marked influence on the composition of the alloy. However, the cathodic current efficiency dropped to 25% when potentials more negative than -1.5 V were applied. A decrease in the copper concentration in the electrodeposition bath resulted in dark-red powdery deposits while an increase of the zinc concentration in the bath, resulted in mirror-bright, well-adherent brass layers, with a copper content as high as 90 wt%. SEM images showed a grain size of 150 nm. XRD analyses indicated that the depositions consisted only of alpha-brass.
10.1016-j.electacta.2015.12.160	2	corrosion; surface; film; electrochemical; films; spectroscopy; layer; current; solution; potential; resistance; composition; x-ray; ions; showed	Combined atomic force-scanning electrochemical microscopy (AFM-SECM) has been explored for monitoring copper ions generated by dissolution of copper samples while recording induced changes in topography. Released Cu2+ ions were detected via reduction to metallic copper at the AFM tip-integrated electrode followed by subsequent re-dissolution in bulk solution by anodic stripping voltammetry. Copper crystals electrodeposited on gold substrates were used as model systems to demonstrate the laterally resolved analysis of topographical changes and the simultaneous measurement of localized cation release, which was anodically activated upon exposure to acidified chloride-containing solution. Finally, the potential of AFM-SECM for monitoring spatially resolved corrosion processes with sub-micrometer resolution was illustrated using a pure copper sample.
10.1016-j.electacta.2015.12.194	2	corrosion; surface; film; electrochemical; films; spectroscopy; layer; current; solution; potential; resistance; composition; x-ray; ions; showed	Corrosion induced structural failures continue to be a costly problem in many industrial situations, and the development of robust corrosion sensing systems for structural health integrity monitoring is still a demanding challenge. The applicability of corrosion monitoring of copper alloys using a boron-doped diamond electrode (BDD) has been performed based on determination of copper ions within localised corrosion microenvironments. The electrochemical behaviour of copper ions on the BDD electrode surface were first reported in details in 0.60 M NaCl aqueous solution, and the results revealed that the electrochemical processes of copper ions on the BDD electrode proceed as two successive single electron transfer steps producing two well-separated pairs of peaks in cyclic voltammograms in the chloride ion containing electrolyte solutions. Compared with perchlorate and sulphate ions, chloride ions were observed with a significant stabilization effect on copper ions via the formation of CuCl2 complex, thus having two well-separated pairs of peaks in the obtained cyclic voltammograms on the BDD electrode in the chloride ion electrolyte solution. The apparent rate constant for the redox couple of Cu2+/Cu+ in chloride ion electrolyte was determined as 0.94 x 10(-6)cm s(-1) by using quasi-steady polarisation technique, thus indicating a quasi-reversible electron transfer process of Cu2+/Cu+ redox couple. Moreover, differential pulse voltammetric results exhibited the BDD electrode is promising for corrosion monitoring of copper alloys with an excellent relationship between peak current and concentration of copper ions without significant interference from the commonly presented metal ions within the simulated marine corrosion environments.
10.1016-j.electacta.2017.02.012	2	corrosion; surface; film; electrochemical; films; spectroscopy; layer; current; solution; potential; resistance; composition; x-ray; ions; showed	Compact Cu-Pd alloys of compositions extending over the entire range are deposited at low overpotentials, from acidic sulphate/perchlorate baths of the two metal ions. XRD data show a lattice parameter following Vegard's law. Porous alloy layers can be deposited from acidic chloride baths under large current densities causing vigorous hydrogen evolution. Good deposits with regular morphology are obtained only from Cu-rich baths, and for Pd contents up to ca 33 at%. XRD investigations indicate a biphasic structure, made of pure Cu and a Cu17Pd83 phase, in variable ratios depending on composition. Single phase porous Cu-Pd materials are obtained by prolonged galvanic displacement of porous Cu layers. Selected electrode materials are tested in the nitrate reduction in alkaline media, comparing the effects of composition and surface area.
10.1016-j.electacta.2017.04.092	2	corrosion; surface; film; electrochemical; films; spectroscopy; layer; current; solution; potential; resistance; composition; x-ray; ions; showed	Commercially pure Cu (Cu), Cu-4.5Sn-0.1Zn, and Cu-9.7Sn-0.1Zn (wt%) were evaluated for corrosion and cation release in modified artificial human perspiration solution. Open circuit corrosion exposures were conducted for up to 130 hours to determine corrosion rate and the fate of Cu and Sn. Released aqueous ion concentrations were monitored via inductively-coupled plasma-optical emission spectroscopy (ICPOES). Operando atomic emission spectroelectrochemistry (AESEC) analysis was utilized to elucidate the fate of Cu, whether in oxides or solution and deduce the dominant valence states, Cu(I)/ Cu(II), of soluble Cu in artificial perspiration. Sn was not observed as a soluble ionic species within ICP-OES or AESEC limits of detection (LOD). Corrosion products were characterized using grazing incidence X-ray diffraction (GIXRD), Raman spectroscopy, and X-ray photoelectron spectroscopy (XPS), and quantified with coulometric reduction (CR). Cu-4.5Sn-0.1Zn displayed the highest corrosion rates in artificial perspiration, followed by Cu-9.7Sn-0.1Zn, and then Cu. Primary corrosion products were Cu2O, with CuCl as an outer solid product, and an inner layer of SnO2 for Sn-containing alloys. Cu was dissolved as cuprous (Cu+) ions. Minor Sn alloying in solid solution catalyzed Cu dissolution which is counteracted at higher Sn contents by a passivating layer of SnO2, achieving complete passivity at 10.3 wt% Sn according to graph theory. Cu-9.7Sn-0.1Zn indicated semi-passive behavior, speculated to be due a SnO2 layer and close proximity (9.7 wt%) to this critical value for passivation (10.3 wt%). The effect of alloyed Sn as a dissolution promoter for electrochemical Cu ion release, critical Sn contents for passivity, and subsequent implications of antimicrobial function are discussed. Oxidized Zn was not detected above LOD nor demonstrated any measurable effect on corrosion in artificial perspiration.
10.1016-j.electacta.2017.04.170	2	corrosion; surface; film; electrochemical; films; spectroscopy; layer; current; solution; potential; resistance; composition; x-ray; ions; showed	This study aims to investigate the electrochemical co-deposition of a Cu-Sn alloy to substitute for the Ni undercoating layer between the outmost coating layer and substrate. The electrodeposition was performed in a sulfuric acid bath containing a mixture of additives such as complex agent (EDTP), auxiliary complex agent (TEA), chelating agent, and pit prevent agent. The effect of each additive on co-deposition was studied by cyclic voltammetry using a rotating disk electrode, which showed that each additive helps to shift the reduction onset potential of Cu closer to that of Sn, thus resulting in uniform Cu-Sn coating. Electroplating of the Sn-rich Cu-Sn alloy was performed for various current densities and plating times, and the results showed that a bright-white-colored, thick, uniform, and compact layer of the above alloy can be deposited under optimized conditions (1 A dm (2) and 30 min). Based on the results of SEM, EDS mapping, XPS, and XRD, we found that Cu and Sn were uniformly distributed throughout the deposited layer with almost equal contents when a relatively low current density (less than 3 A dm (2)) was employed.
10.1016-j.electacta.2017.08.097	2	corrosion; surface; film; electrochemical; films; spectroscopy; layer; current; solution; potential; resistance; composition; x-ray; ions; showed	Cu-Ag alloys are promising materials for electrical interconnections due to their combination of high conductivity and superior mechanical strength . In the present work, Cu-Ag alloys were electrodeposited from a cyanide-free electrolytic bath and different Ag percentages, ranging from 3 to 15 at%, were obtained by controlling the deposition conditions. Electrochemical processes occurring during Cu-Ag deposition were investigated by means of cyclic voltammetry. Structural properties were examined by TEM and XRD and hardness was assessed by microindentation. TEM observations revealed the presence of nano-sized Ag precipitates at low Ag content, and the composition of the Cu-rich and Ag-rich phases in high-Ag alloys was deduced from XRD measurements. As-deposited alloys exhibited high hardness values and the contribution of solid-solution hardening was highlighted.
10.1016-j.electacta.2017.08.155	2	corrosion; surface; film; electrochemical; films; spectroscopy; layer; current; solution; potential; resistance; composition; x-ray; ions; showed	Cu2ZnSnS4 (CZTS) absorber layers were synthesized by electrodeposition of Cu-Zn-Sn (CZT) alloys using horizontally or vertically oriented electrodes, followed by sulfurization. A significant improvement in compositional homogeneity was observed for the horizontal vs. vertical deposition configuration, most probably due to the absence of buoyancy-induced convection and the improved uniformity of the current distribution in the former. The morphology of the two CZT films is similar, but the films grown from the horizontal, facing down electrode, show some pinholes related to the adhesion of hydrogen bubbles. The horizontally grown and sulfurized CZTS films show also a better homogeneity and improved phase purity, as demonstrated by EDS mapping and imaging. The disorder due to anti-site defects in as-sulfurized CZTS films is decreased by gentle annealing, which also results in improved crystallinity. Liquid junctions were utilized to measure film photoactivity, showing that the horizontally grown films exhibit twice as much the photocurrent from the vertically grown ones; the dark current however was higher in the former, probably owed to the presence of pinholes that provide a short circuit between the electrolyte and substrate. (C) 2017 Published by Elsevier Ltd.
10.1016-j.electacta.2017.10.027	2	corrosion; surface; film; electrochemical; films; spectroscopy; layer; current; solution; potential; resistance; composition; x-ray; ions; showed	Deposition of Cu-Sn alloys from a methanesulfonic acid electrolyte containing small amounts of benzyl alcohol was investigated. Polarisation experiments (cylic and linear sweep voltammetry) were carried out using a rotating disc electrode to identify the reduction and dissolution processes that take place in the system and to determine the effect of the solution constituents on them. Potentiostatic deposition was performed onto a rotating cylinder electrode and the resulting deposits were charactised using SEM and XRD. The results showed that co-deposition of copper and tin is possible even at potentials less cathodic than tin discharge potential. The latter was attributed to the underpotential deposition of Sn2+ on a copper substrate. Smooth and compact deposits were obtained at various deposition potentials and Cu2+ concentrations, with Sn contents between 1.6-62.4 wt%. Several stable phases, such as pure copper, alpha-CuSn, epsilon-Cu3Sn and eta '-Cu6Sn5 phase, were detected at different operating conditions. Finally, it was found that BA increases the amount of tin in the deposit when Cu2+ concentrations in the solution is kept low, especially at high overpotentials. This additive also inhibits the formation of dendrites and reduces surface roughness.
10.1016-j.electacta.2017.12.083	2	corrosion; surface; film; electrochemical; films; spectroscopy; layer; current; solution; potential; resistance; composition; x-ray; ions; showed	Electrochemical studies have been conducted at copper microelectrodes (125, 50, and 25 mu m in diameter) immersed in aqueous 0.5M NaCl. Cyclic and linear sweep voltammetry were used to explore the corrosion of copper in chloride media. Cyclic voltammetry revealed the reversible Cu(I)/Cu(0) potential at approximately -0.11 V vs. SCE associated with the formation of a dense CuCl blocking layer (confirmed by in situ Raman and fluorescence measurements). Although continuous dissolution of Cu(I) occurs, only an increase in the driving potential into the region of the Cu(II)/Cu(I) potential at approximately +0.14 V vs. SCE started more rapid and stochastic dissolution/corrosion processes. The corrosion process is demonstrated to be linked to two distinct mechanisms based on (A) slow molecular dissolution and (B) fast colloidal dissolution. A polymer of intrinsic microporosity (PIM-EA-TB) is employed to suppress colloidal processes to reveal the underlying molecular processes.
10.1016-j.electacta.2018.06.125	2	corrosion; surface; film; electrochemical; films; spectroscopy; layer; current; solution; potential; resistance; composition; x-ray; ions; showed	The antimicrobial function of Cu surfaces can be linked to soluble Cu release from corrosion. However, direct replacement of high-touch surfaces with Cu-based alloys is limited by knowledge gaps regarding how alloying directly relates to corrosion. A systematic approach to determine the role of Sn as a solute element and the minimum alloy content for passivation has been lacking. High-purity arc-melted binary alloys of Cu-Sn with specific additions of 0.1,1,5, and 10 wt% Sn were compared to pure Cu and Sn. The role and amount of Sn in corrosion products (patina) formed on the alloy surface as a function of alloying was interrogated in artificial perspiration. The fate and identity of the solute (Sn) and solvent (Cu) elements following corrosion, as soluble ions or insoluble corrosion products, was investigated. Alloy patinas became increasingly enriched in Sn corrosion products identified as SnO2 with increasing Sn content in the alloy. The critical alloy content for complete SnO2 layer coverage were theoretically quantified through a model based on interfacial surface energy. The predicted minimum solute content for a complete conformal inner layer of SnO2 was 1 wt% Sn whereas experimentally complete coverage was achieved only at 10 wt% Sn. Differences between theory and experiment are discussed.
10.1016-j.electacta.2018.09.181	2	corrosion; surface; film; electrochemical; films; spectroscopy; layer; current; solution; potential; resistance; composition; x-ray; ions; showed	The elemental dissolution of Cu-Zn alloys was investigated as a function of Zn content ranging from 0 to 45 wt%. Atomic emission spectroelectrochemistry (AESEC) was utilized to directly monitor Cu2+ and Zn2+ release and oxide growth as function of time during potentiodynamic experiments. It was determined that Cu dissolution undergoes a simultaneous mechanism of Cu2O formation and Cu2+ release. The addition of Zn in Cu-Zn alloy does not measurably change the dissolution mechanism of Cu2+ and the rate of aqueous Cu2+ was only dependent on the potential. Zn dissolution was however blocked by the formation of a Cu(0) film which shifted the Zn dissolution in the anodic direction.
10.1016-j.electacta.2018.11.189	2	corrosion; surface; film; electrochemical; films; spectroscopy; layer; current; solution; potential; resistance; composition; x-ray; ions; showed	In this work, copper-tin (Cu-Sn) alloy coating was prepared in 1-butyl-3-methylimidazolium chloride ([BMIM]Cl) using electrodeposition method. The electrochemical behaviors of different electrolytes and the electrodeposition reversibility of Cu-Sn alloy were studied using cyclic voltammetry (CV). The electro-crystallization mechanism was investigated using chronoamperometry at different step potentials on glassy carbon (GC) electrode. The micromorphology and phase composition of Cu-Sn alloy coatings were characterized using scanning electron microscopy (SEM) and X-ray diffraction (XRD). The results showed a new reduction peak located at -0.50 similar to -1.00 V, which belonged to Cu-Sn co-deposition. The reduction of Cu-Sn alloy in this system was an irreversible process. The electro-crystallization of Cu-Sn alloy followed the three-dimensional instantaneous nucleation. The results for micro-morphologies showed that, when the potential is changed, different microstructures can be formed, whereas the morphology changed from snow-like to cypress leaf-like shape. The results for phase composition showed that Cu-Sn alloy coating at different electrodeposition potentials consisted of pure cubic system Cu13.7Sn phase. Additionally, the Cu-Sn alloy deposition from [BMIM]Cl system showed a preferred orientation on (220) crystallographic plane, which is different from the standard card.
10.1016-j.electacta.2019.03.064	2	corrosion; surface; film; electrochemical; films; spectroscopy; layer; current; solution; potential; resistance; composition; x-ray; ions; showed	In the electrorefining of Cu, the precipitation of copper sulfate on the anode surface causes passivation, which decreases current efficiency. Because the presence of Sb in a Cu anode is known to accelerate passivation, this study investigated the anodic behaviors of Cu-Sb alloys in a H2SO4-CuSO(4)electrolyte by a direct observation method that combined optical microscopy with the channel flow double electrode technique. When a Cu-Sb (5 wt% Sb) anode (here denoted Cu-5 wt%Sb) with Sb segregation was dissolved, the Sb-rich region remained on the surface, inhibiting Cu dissolution and ion transfer and resulting in acceleration of passivation, which was observed as a drastic decrease in current density during voltammetry. However, a Cu-5 wt%Sb anode solutionized by heat treatment showed a moderate decrease in current density in some measurements, indicating prevention of passivation. It was observed that the dissolution of the solutionized Cu-5 wt%Sb anode generated an Sb-rich layer with complex sulfate compounds on its surface and accompanying pits. Copper sulfate precipitated selectively on the Sb-rich layer and grew into coarse grains, without covering the entire anode surface. These results suggest that passivation can be prevented by controlling the microstructure, even when an anode contains Sb. The results of this work are expected to contribute to the development of an efficient electrorefining process of Cu anodes containing high concentrations of Sb.
10.1016-j.electacta.2019.04.064	2	corrosion; surface; film; electrochemical; films; spectroscopy; layer; current; solution; potential; resistance; composition; x-ray; ions; showed	Although potentiodynamic polarization is a common technique for determining corrosion current, there is no consensus on the choice of scanning parameters. This study explores a 1D mathematical model of copper under oxygen reduction in a chloride containing medium to quantify the effects of scan rate, starting overpotential, and scan direction on the features of polarization curve. All the relevant tendencies of the cathodic branch are reproduced experimentally and explained by local oxygen consumption and coverage by CuCl. The corresponding effects on the precision of determining corrosion current are discussed, revealing that the largest deviation of up to 50% is obtained for the slowest scan rate and largest starting overpotential. (C) 2019 Published by Elsevier Ltd.
10.1016-j.electacta.2019.07.007	2	corrosion; surface; film; electrochemical; films; spectroscopy; layer; current; solution; potential; resistance; composition; x-ray; ions; showed	Nanoporous metals offer an open nanostructured network with a very high specific area and nanoporous templates can be used in many applications from energy storage and catalysis to sensors. One way to produce nanoporous (noble) metal templates is the dealloying approach starting from an alloy based on elements of different reactivities. In this work, co-electrodeposition of CuZn alloys is performed with triethanolamine (TEA) as a complexing agent to produce CuZn precursor films for further dealloying. To investigate the phenomena of electrodeposition, the electrochemical behavior of a copper substrate is compared to an ITO substrate in different NaOH electrolytes, with and without metal salt or additive. Cyclic voltammetry shows that a passivating layer forms on a copper substrate but is of lower stability in the presence of TEA. Potentiostatic electrodeposition from copper sulfate and zinc sulfate with TEA leads to Zn-rich g-brass coatings. Nanoporous structuration is obtained after chemical dealloying of the electrodeposited alloy coatings. The dealloying process induces an increase of the electrochemically active surface area by a factor 25. The nanoscale structuration is confirmed by FIB-SEM. (C) 2019 Published by Elsevier Ltd.
10.1016-j.electacta.2021.137969	2	corrosion; surface; film; electrochemical; films; spectroscopy; layer; current; solution; potential; resistance; composition; x-ray; ions; showed	Cu-Zn alloy micropillars were fabricated using microanode-guided electroplating (MAGE) at a constant voltage of 4.6 V under an initial inter-electrode gap of 30 um in pyrophosphate baths. Energy-dispersive spectroscopy and X-ray diffractometry analysis revealed that the micropillar alloys exhibit an increase in the Zn content from 8.05 at% (in alpha phase) to 54.60 at% (in beta, and beta' phases) with an increase in the ratio of [Zn2+]/[Cu2+] in the bath from 8/1 to 128/1. Transmission electron microscopy revealed that the Cu-Zn alloy micropillars were composed of nano-grains with different sizes depending on the bath employed. Nano-indentation test indicated that the micropillar containing 40.51 at% Zn (in presence of beta-phase) exhibits the maximum hardness (at 5.30 GPa) and highest Young's modulus (at 113.64 GPa). Simulation of the electric field using the commercial software COMSOL 5.2 revealed that the highest field strength centralized at the cylindrical top displayed only a slight increase (from 152.2 to 152.5 kV/m) with an increase in the ratio of [Zn-2(+)]/ [Cu2+] in the bath . Potentiodynamic cathodic polarization is useful for understanding the mechanism of microanode-guided electroplating. Electrochemical impedance spectroscopy performed at characteristic potentials confirms the mechanism extremely well.
10.1016-j.electacta.2021.138867	2	corrosion; surface; film; electrochemical; films; spectroscopy; layer; current; solution; potential; resistance; composition; x-ray; ions; showed	Atomic force microscopy (AFM), X-ray Diffraction (XRD), and electrochemical techniques (voltammetry and chronoamperometry) were used to evaluate the influence of the concentration of silver nanoparticles (AgNPs) on the electrodeposition and nucleation mode of Cu-Zn/AgNPs composite coatings. The voltammetry analysis display three reduction processes during the formation of the Cu-Zn/AgNPs metal composite. The first process (peak P-C(I)) appears in the potential range of -0.5 to -1.2 V vs. saturated calomel electrode (SCE) and corresponds to the reduction of Cu(II) to Cu(0). The second and the third processes, peak P-C(II) and P-C(III), respectively are located in the range of -1.4 to -1.6 V vs. SCE and are associated with the deposition of various crystalline phases of the Cu-Zn alloy. The potential of the P-C(I) peak is shifted in the negative direction by increasing the concentration of AgNPs in the electrolytic solution. This effect is related to the adsorption of AgNPs on the substrate surface. From the chronoamperometry study, it was possible to disclose a process of nucleation and growth of phases in the potential region where the peak P-C(I) is formed. This nucleation process may be explained in terms of a combination of an adsorption process and a diffusion-controlled three-dimensional crystal nucleation and growth mechanism (3D(-dC(PCI))). In the potential range where the P-C(II) and P-C(III) peaks appear, a second nucleation process take place. This nucleation process involves three mechanisms: an adsorption process and two three-dimensional (3D) mechanisms of the kinetics of nucleation and diffusion-controlled growth of bimetallic phases (3D(dc-bimetal)) that correspond to the nucleation of various phases of the alloys. On the other hand, a decrease in the nucleation kinetics parameters (density of active sites formed (N-0) and the nucleation rate (A)) is observed with the increasing concentration of the AgNPs in the electrolytic solution. XRD analysis confirmed the formation of various crystalline structures of the Cu-Zn alloy at -1.50 V vs. SCE. Furthermore, AFM showed that the morphology and size of the formed metal clusters strongly depend on the content of the AgNPs in the bath .
10.1016-j.electacta.2021.139695	-1		In alloy electrodeposition, estimations of the initial transient and the potential vs. composition trend of the film system is important for material design, deposition procedure and the deposit characterization. However, solving the diffusion-migration-convection problem based on common simulation methods is often too burdensome and too resource-consuming for ordinary tasks in the context of alloy electrodeposition works. In this work, based on a stagnant diffusion layer model, we have proposed simple estimates on (1) the potential-composition curve, (2) the thickness of the initial deposit, and (3) the time interval to reach the steady state deposition. These estimates were validated by using a Cu-Ag acidic sulfate electrolyte, which upon electrodeposition results in an immiscible Cu-Ag alloy, both at n-Si(001) or at polycrystallline Ru substrates. The limiting current of Cu-Ag electrodeposition is compared with the numerical results given by Selman and Newman in 1970s [17] , whereas the film composition deposited at the limiting current from various electrolyte constitutions is compared with the model suggest by Brenner based on stagnant diffusion layer model [21] . The proposed estimation methods show good agreement with the observed values, despite being highly simplified, since they are compared with the actual mass-transfer problem of ions under convection and migration.
10.1016-j.electacta.2023.142744	2	corrosion; surface; film; electrochemical; films; spectroscopy; layer; current; solution; potential; resistance; composition; x-ray; ions; showed	The galvanic corrosion behavior of Cu-Fe-Zn trimetallic couple and its factors were investigated in acidic chloride solution using electrochemical and numerical methods. Results demonstrated that the potential difference of galvanic couple reflects only the thermodynamic tendency of galvanic corrosion, while the cathodic kinetic process controls the galvanic corrosion rate. It is found that the galvanic effect between Cu and Zn is much less than that between Zn and Fe when ohmically coupled. This is opposite to the theory of galvanic series. Despite possessing the maximum corrosion potential difference as the driving force, the galvanic current of Zn-Cu couple is less than that of Zn-Fe couple with equal area ratio. This drives the intermediate metal (Fe) to act as the main cathode in Cu-Fe-Zn trimetallic couple. Furthermore, it is found that Fe can be transformed into the anode due to the area change of Cu. The electrochemical experimental results are in good agreement with the FEM, suggesting that this method can accurately predict the galvanic corrosion behavior of multielectrode systems.
10.1016-j.electacta.2024.144769	-1		In this study, Ni was employed to enhance the mechanical properties of nanotwinned copper (NT-Cu) foils due to its excellent oxidation resistance and compatibility with Cu. The tensile strength of the NT-Cu foils was enhanced 12.6 % (752.8 to 847.3 MPa) by Ni co-electrodeposition. During the electroplating, it was found that Ni ions inhibited the Cu growth, causing the reduction potential (overpotential) to shift in the negative direction. It resulted in a reduced deposition rate and decreased the twin spacing of the foils. Additionally, Ni ions acted as impurities for the grain refinement. Time of flight secondary ion mass spectrometry (TOF-SIMS) results indicated that Ni atoms were deposited on the top and bottom of the foils due to the limiting current density of Ni. The NTCu-Ni exhibited low roughness and performed superior resistance to oxidation compared to the NT-Cu. X-ray photoelectron spectroscopy (XPS) was also utilized to characterize the oxidation of the Cu (Ni) alloys. These mechanisms contributed to high strength, low resistivity, and excellent oxidation resistance of the NT-Cu-Ni foils for future battery materials.
10.1016-j.electacta.2024.144980	14	strength; properties; conductivity; electrical; mechanical; cu-; grain; mpa; electrical conductivity; aging; precipitation; phase; mechanical properties; tensile; phases	The study simulated copper corrosion in a bentonite/groundwater solution, analyzing the kinetics of metal passivation through potentiodynamic polarization, potentiostatic polarization, and electrochemical impedance spectroscopy experiments. Morphological characterization provided insights into corrosion development patterns, and the mechanisms by which bentonite affects copper corrosion were comprehensively elucidated based on the point defect model. The findings revealed that bentonite affects copper corrosion resistance through Donnan exclusion, cation adsorption, and hydrolysis salt effects. At lower potentials, bentonite aids in inhibiting anodic dissolution, reducing the polarization current by approximately 75 % under certain conditions. With increasing bentonite content, the induction time for stable pitting corrosion shortens significantly, down to 10 %, the current surge before breakdown intensifies, and the breakdown potential decreases. When the bentonite volume ratio exceeds 0.5/0.1, the breakdown potential of OFP-Cu/OF-Cu markedly decreases and stabilizes at 0.1/0 VSCE. The microscopic mechanism of pitting corrosion induced by bentonite hydrolysis salts was elucidated using the point defect model, calculating the polarizability of the passive layer/outer layer interface as alpha = 0.1. The reliability of the cation adsorption and adsorption-desorption mechanisms was confirmed through experimental data fitting, point defect model fitting, and theoretical analysis.
10.1016-j.electacta.2025.147143	14	strength; properties; conductivity; electrical; mechanical; cu-; grain; mpa; electrical conductivity; aging; precipitation; phase; mechanical properties; tensile; phases	This study investigates the effects of hydrostatic pressure and dissolved oxygen in deep-sea environments on the nature of the corrosion product film formed on 70/30 Cu-Ni alloy. The composition, structure, and properties of the film were elucidated using polarization curves, electrochemical impedance spectroscopy, scanning electron microscopy, and transmission electron microscopy. The results demonstrate the spontaneous formation of a duallayer corrosion film in 3.5 wt% NaCl solution, featuring a nanocrystalline/amorphous hybrid outer layer composed primarily of Cu2(OH)3Cl and an amorphous nickel-enriched inner layer. Hydrostatic pressure at 10 MPa was found to significantly enhance the compactness of the outer layer, resulting in a dramatic improvement in film impedance from 37.06 to 765.68 k ohm & sdot;cm2. Furthermore, the synergistic interaction between elevated dissolved oxygen content and hydrostatic pressure induces substantial microstructural densification of the outer layer, accompanied by a notable positive shift in corrosion potential from -535 mV to -180 mV.
10.1016-j.electacta.2025.147207	2	corrosion; surface; film; electrochemical; films; spectroscopy; layer; current; solution; potential; resistance; composition; x-ray; ions; showed	The threshold concentrations of Cu2+ and Zn2+ required for the formation of fluoride-containing corrosion product films on copper-zinc alloy are calculated using the dissolution-ionization-diffusion-deposition model of the Cu-Zn-F system proposed in this work. Based on the model, the mechanism underlying dezincification of copper-zinc alloy and negligible formation of metallic fluoride on surface, even in saturated NaF solution, is explained. Furthermore, fluoride-containing films are successfully fabricated on the alloy surface with the addition of certain concentration of Cu2+ and Zn2+, as calculated from the model. This work provides a promising approach for designing the corrosion product film via immersion.
10.1016-j.electacta.2025.147463	-1		Copper-tin alloys are critical due to the excellent strength, corrosion resistance, and wide range of applications in engineering and manufacturing. However, it was a significant challenge to fabricate Cu-Sn coatings with uniform thickness and chemical composition in deep small blind holes. In this paper, a friction assisted jet electrode-position with a variable diameter auxiliary anode was proposed. The profile of variable diameter anode was optimized by the validated multiphysics simulation. Experiments of jet electrodeposition and friction assisted jet electrodeposition (FJED) were conducted to fabricated samples. Results of characterizations showed that coatings prepared by FJED had uniform thickness and chemical composition. The hardness and adhesion were enhanced by removing hydrogen bubbles. All coatings exhibited an excellent corrosion resistance. The mechanism of FJED was revealed that the variable diameter anode improved the uniformity of coatings, and frictional brush enhanced the mechanical properties of coatings.
10.1016-j.eng.2024.07.024	-1		Immiscible bimetal systems, of which tungsten-copper (W-Cu) is a typical representative, have crucial applications in fields requiring both mechanical and physical properties. Nevertheless, it is a major challenge to determine how to give full play to the advantages of the two phases of the bimetal and achieve outstanding comprehensive properties. In this study, an ultrafine-grained W-Cu bimetal with spatially connected Cu and specific W islands was fabricated through a designed powder-mixing process and subsequent rapid low-temperature sintering. The prepared bimetal concurrently has a high yield strength, large plastic strain, and high electrical conductivity. The stress distribution and strain response of individual phases in different types of W-Cu bimetals under loading were quantified by means of a simulation. The high yield strength of the reported bimetal results from the microstructure refinement and high contiguity of the grains in the W islands, which enhance the contribution of W to the total plastic deformation of the bimetal. The high electrical conductivity is attributed to the increased mean free path of the Cu and the reduced proportion of phase boundaries due to the specific phase combination of W islands and Cu. This work provides new insight into modulating phase configuration in immiscible metallic composites to achieve high-level multi-objective properties. (c) 2024 THE AUTHORS. Published by Elsevier LTD on behalf of Chinese Academy of Engineering and Higher Education Press Limited Company. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/).
10.1016-j.engfailanal.2018.07.035	-1		The current work presents a failure analysis study conducted on a fractured mechanical fastener made of Cu-12Mn alloy. The fastener was obtained from a flange of a large-diameter steel tube operating in a sea submersible platform. Macrofractography and Microfractography, Standard Optical Metallography, Scanning Electron Microscopy (SEM), X-ray Fluorescence (XRF) and Energy-Dispersive X-ray Spectroscopy techniques as well as Numerical Modeling were employed to assist the investigation. Fracture was eventually attributed to the synergistic action of fatigue and selective leaching (corrosion-assisted fatigue).
10.1016-j.engfailanal.2020.104955	5	materials; thermal; heat; properties; material; welding; sintering; fusion; strength; laser; heat sink; thermal conductivity; mechanical; sink; manufacturing	The industrial production of Cu-Fe-P billet Direct Chill (DC) casting exhibits often difficulties related to the generation of surface cracks on the cast piece. The demand for always higher productivity leads to increased casting speed with significant cooling requirements. This in turn affects the thermal gradient within the billet leading often to stress concentration responsible for surface cracking. In order to deal with this issue while keeping productivity at high levels lowering the industrial cost, a 2D thermo-mechanical Finite Element (FE) model was developed, which was applied and validated based on industrial conditions. The model targets to predict the material failure during DC casting. Based on the proposed approach the billet's temperature profile and its stress state during secondary cooling are calculated. The simulation results revealed that strong cooling using water jets cannot be applied immediately at the exit of the mold at any casting speed. However, as the distance of the secondary cooling unit from the mold exit increases, the stress concentration drops significantly, so that the jet nozzles can be applied from 750 to 2500 mm away from the mold, depending on the casting speed, without material failure. On the contrary, milder water spraying applying a lower local heat transfer coefficient, but on the same time covering broader impact surface, can result in a more efficient billet cooling. Thus, due to milder cooling the cast-piece material is less prone to failure and cooling can be applied immediately at the mold exit. Furthermore, a sequence of numerous spray arrays can further increase the cooling capacity. Concluding, it is shown that a validated thermo-mechanical 2D FE model can provide deeper insights used industrially as a setting tool, which optimizes the casting conditions in order to further improve productivity and the quality characteristics of the as-cast billet.
10.1016-j.engfailanal.2023.107549	14	strength; properties; conductivity; electrical; mechanical; cu-; grain; mpa; electrical conductivity; aging; precipitation; phase; mechanical properties; tensile; phases	Cu/Al tribological pairs play a crucial role in maintaining the efficient operation of a wide range of engineering components. However, their durability is often compromised by wear-induced damage, which involves the accumulation of material at the Cu/Al friction interface. This study investigates the intricate wear behavior of Cu/Al tribological pairs under electrical current, with a specific emphasis on material transfer events occurring at the interface. Our findings reveal that the applied electric current exerts a lubricating effect on the sliding contact friction, resulting in reduced adhesive wear. However, it concurrently exacerbates fatigue-induced delamination, abrasive wear, and electrical wear. Through detailed analysis of interface temperatures and microstructure characterizations, we demonstrate that Al deposit adhesion occurs through interfacial metal mixing and nanoscale diffusion in the presence of only mechanical friction. Conversely, at high electrical currents, interfacial melting transpires, resulting in robust adhesion facilitated by the formation of an intermetallic compound. Our findings offer valuable insights into the microscopic adhesion events occurring in Cu/Al tribological pairs and provide guidance for developing innovative coating systems aimed at reducing material deposition in Cu/Al current-carrying friction interfaces.
10.1016-j.engfailanal.2023.107861	14	strength; properties; conductivity; electrical; mechanical; cu-; grain; mpa; electrical conductivity; aging; precipitation; phase; mechanical properties; tensile; phases	In this research, we aimed to investigate the self-healing behavior of Cu-2Be alloy (UNS C17200), which is used as a non-magnetic high-strength material, under various loading conditions, both static and dynamic, including tension-annealing and fatigue tests. We observed crack filling in all heat-treated and tested samples, specifically those subjected to solution heat treatment at 800 degrees C, under-aged (UA) conditions, and aging conditions at 320 degrees C for 5 and 30 min. The latter two phenomena were triggered by the precipitation of gamma (CuBe) and gamma' phases after straining and heat treatment. The synergistic effect of dynamic aging and dislocation recovery resulted in increased ductility in the pre-strained and UA sample, as evidenced by post-fracture elongation, compared to specimens elongated up to a certain pre-strained level followed by annealing and aging. In conclusion, uniaxial fatigue testing revealed that the lifetime of UA Cu-2Be samples surpasses that of annealed and fully aged ones due to the efficient preparation of self-healing effects brought about by the precipitation of intermediate and final age-hardening phases, dislocation rearrangement, and grain boundary reinforcement through beryllium atoms. To characterize the precipitated CuBe, we conducted XRD, XPS, and DIGE phase identification analyses, alongside relevant electron microscopy analyses. Additionally, we investigated the possibility of crack closure by integrating the findings from the positron annihilation lifetime spectroscopy and coincidence Doppler broadening spectroscopy outputs, thus validating the results of spectroscopy and diffraction.
10.1016-j.engfailanal.2024.108206	-1		Advanced strategies and techniques in the Laser Powder Bed Fusion (LPBF) process for printing Cu-Cr-Zr alloy must be created to overcome the major flaws such as cavity formation, unstable thermal capillary convection and thermodynamic instability. In this research, the significant process variables in the LPBF techniques such as Laser Power (LP) of 430, 500 and 570 W, Scanning Velocity (SV) of 550, 750 and 950 mm/s, Hatching Distance (HD) of 0.06, 0.08 and 0.10 mm were considered into account to fabricate a crack-free Cu alloy coupon with maximum Relative Density (RD), Ultimate Tensile Strength (UTS) and Reduced Elastic Modulus (REM). To optimize the process variables, a Criteria Importance Through Intercriteria Correlation (CRITIC) associated with the Weighted Aggregated Sum Product Assessment (WASPAS) approach was employed. Finally, the confirmation experiments were performed for the optimal settings (LP of 430 W, SV of 750 mm/s and HD of 0.06 mm) and the initial settings (LP of 570 W, SV of 550 mm/ s and HD of 0.10 mm). The optimal settings show an 8.6 % enhancement in relative density of 99.82 %, which also reflects in 47 % improvement in UTS of 336 MPa and a 27.8 % enhancement in REM of 147.45 GPa compared with the initial settings. With the help of fracture morphology, the effect of defect development on the propagation of fractures on the printed coupons was also investigated. Moreover, the confirmation experiments aligned more with the CRITIC-integrated WASPAS approach .
10.1016-j.engfailanal.2025.109289	-1		The The study indicates that the optimal location for investigating erosion-corrosion phenomena in elbows is the posterior half of the bend. The B10 copper-nickel alloy can still form a protective film under the erosive corrosion action of sandy seawater, with the peak protectiveness of the film occurring between 0-1.5 m/s. Flow rates are categorized into three classes: low (<2.5 m/s), medium (2.5-3.5 m/s), and high (>3.5 m/s), with a systematic analysis conducted on the sandy seawater erosion-corrosion mechanisms at these three flow rates.
10.1016-j.engfailanal.2025.109915	-1		The development of cast alloys with excellent resistance to hydrogen embrittlement is currently sought as a cost-effective solution for large-size components, such as large-diameter valves designed for liquefied hydrogen applications. This study investigated the effects of chemical composition on hydrogen-induced ductility loss and tensile properties in Cu-Al-Ni-Fe-Mn cast alloys, classified as CAC703 under JIS H5120. Eight alloys with varying Al, Ni, and Fe contents were prepared. Selected specimens were precharged with hydrogen gas at 100 MPa and 270 degrees C for 200 h, followed by slow strain-rate tensile (SSRT) testing in air at room temperature (RT). Microstructural analysis revealed kappa precipitates dispersed in an Al-containing Cu solid solution, with increased Al content resulting in grain refinement. Although the relative reduction in area (RRA) ranged from 0.78 to 1.45, these deviations showed no correlation with tensile strength or hydrogen content. Fracture surfaces consistently revealed casting defects as the primary cause of failure. A predictive model based on elasto-plastic fracture mechanics was proposed to quantify fracture behavior. No evidence of hydrogen-induced ductility loss was observed in any of the tested alloys. Furthermore, the RRA values at low-temperature SSRT testing ranged from 0.95 to 1.01, indicating no significant effect on ductility. Multivariate analysis yielded predictive equations for tensile strength (TS) and elongation (EL) based on Al, Ni, and Fe contents: TS [MPa] = 10.242 + 4.31781Fe + 9.2255 Ni + 65.263Al and EL [%] = 158.25-1.0109Fe-1.8709Ni 12.458Al in wt%, with Al exerting the most significant influence.
10.1016-j.engfracmech.2015.12.011	-1		This presented paper deals with the mechanical properties of diffusion alloyed Cu-Ni-Mo sintered steel. The material's response to static and dynamic loading is summarized from previous work and referenced, while the testing methods and results for the fracture mechanics' parameters are discussed in greater detail. It was observed that despite being more brittle, additionally quenched and tempered sintered steel has a lower crack growth rate than basic sintered steel. However, fracture and impact toughness are reduced after quenching and tempering. The crack growth threshold was found to be very similar and slightly higher after additional heat treatment.
10.1016-j.engfracmech.2022.108658	-1		This work uses high-energy synchrotron X-ray diffraction (HEXRD), atomic force microscope (AFM), nanoindentation and EBSD technology to explore a new method for measuring residual stress in strong R {124} 211 texture alloys, and the distribution of residual stress and Young's modulus in different crystal orientations. Compared with the traditional Voigt and Reuss model, for the textured Cu-Ni-Si-Co alloy, a local Voigt and Reuss inter-grain interaction model based on HEXRD diffraction technology is established, which can more accurately characterize the residual stress of superficial layer (230 mu m). The local stress model provides a new X-ray diffraction method for testing the residual stress of textured materials. Aiming at the textured Cu-Ni-Si-Co alloy with compressive stress, the quasi-in-situ method combining EBSD and nanoindentation is used to characterize the residual stress of different crystal orientations in the microdomain. The hard orientation [1 1 1] grain direction has the highest residual stress, and the soft orientation [100] grain direction has the lowest residual stress, and the residual compressive stress in the hard orientation is about twice that of the soft orientation. In addition, the Young's modulus of the material is also the largest on [111] hard-oriented grains and the smallest on [100] softoriented grains.
10.1016-j.engfracmech.2025.111113	14	strength; properties; conductivity; electrical; mechanical; cu-; grain; mpa; electrical conductivity; aging; precipitation; phase; mechanical properties; tensile; phases	The damage behavior of C17200 beryllium copper alloy during very high cycle fatigue (VHCF) at a loading frequency of 20 kHz was investigated. Samples subjected to varying loading were characterized and evaluated to clarify the impact of internal microstructure on VHCF performance. The findings demonstrate that grain boundary precipitates (GBPs) significantly influence the VHCF fracture behavior of the C17200 alloy. GBPs facilitate a change in fracture mode from the crack initiation phase to the crack propagation phase. The interaction between GBPspersistent slip bands (PSBs) created a distinctive phenomenon in the crack initiation phase, wherein cracks originate from the GBPs and propagate along the PSBs. Furthermore, it was verified that areas with a high density of precipitates lead to their detachment. This study introduces the inaugural examination of the VHCF performance and fracture process of C17200 alloy. A novel fatigue life prediction model, which integrates the impact of precipitates as a critical factor, was established, demonstrating strong concordance with experimental results.
10.1016-j.engfracmech.2025.111474	-1		Trimodal nanostructured (NS) metal-based composites incorporate advantages of a strong nanograined or ultrafine-grained metal matrix phase, a ductile coarse-grained (CG) metal phase, and a ceramic reinforcement phase. In this study, computer simulations based on the combination of a mechanism-based strain gradient plasticity theory, the Johnson-Cook failure criterion, and the extended Drucker-Prager plasticity model have been performed to study effects of distribution and shape of CG regions, together with size and volume fraction of ceramic reinforcement particles, on tensile behavior of trimodal NS Cu-based composites. All of them have been found to have significant influences on the overall strength and ductility. This study indicates that staggered arrangement of CG regions leads to higher overall strength and ductility than array arrangement of CG regions most of the time. The investigation further clarifies that the shape of CG regions can change their fracture mode when they play a role of bridging. The simulations show that the size of ceramic reinforcement particles is important since it affects the surrounding stress concentration. The results show that the trimodal NS Cu-based specimen can be stronger than bimodal NS Cu specimen only when the matrix grain size is quite large so that the selection of each phase has great influences on the overall strength and ductility.
10.1016-j.engstruct.2014.01.053	3	sma; shape; shape memory; memory; smas; superelastic; bars; damping; cu-al-mn; mechanical; bending; applications; numerical; sma bars; material	Steel cables, tendons and tie-rods are the key components of many structures including masonry arches and vaults, timber roof trusses and several post-tensioned structures. In this paper, a device prototype based on the superelastic properties of Cu-based Shape Memory Alloys (SMAs), is proposed to enhance the thermal behavior of such structural elements. The thermal behavior of steel tie-rods with and without SMA is evaluated through comprehensive experimental tests in thermal room. During the tests, different temperature-time histories are considered, with air temperature varied between -10 degrees C and 40 degrees C. The results of the experimental tests confirm the great effectiveness of the proposed SMA device, with reductions of force changes due to air temperature variations of the order of 80-90%, compared to steel tie-rods without SMA. In the paper, the main structural components and basic functioning principles of a SMA-based device prototype for masonry arches and vaults are presented and aspects related to its implementation in practice are discussed in detail.
10.1016-j.engstruct.2018.08.072	3	sma; shape; shape memory; memory; smas; superelastic; bars; damping; cu-al-mn; mechanical; bending; applications; numerical; sma bars; material	Self-centering earthquake resistant systems have attracted the attention of researchers because of their promising potential in controlling seismic residual drifts, and, therefore, reducing the associated repair costs. The use of NiTi superelastic shape memory alloy (SMA) constitutes a considerable portion of this research . Cu-Al-Mn superelastic SMA has been recently developed to eliminate the high cost of Ni-Ti SMA, as well as, to have better machining characteristics. This paper explores the use of Cu-Al-Mn SMA bars to relocate the plastic hinge of concrete beams through an experimental numerical study. The cyclic performance of four beams was examined. The first was reinforced with steel bars and the remaining three were reinforced with combination of SMA and steel bars. The location of the SMA bars was different for each of the examined beams. The beams were loaded such that the moment diagram is zero at midspan and maximum at the ends to simulate the expected seismic moments. Results of the experimental numerical investigation confirmed the recentering capability of SMA RC beams. Relocating the plastic hinge, by placing Cu-Al-Mn SMA bars away from the beam ends, improved the strength, rigidity, and energy dissipation.
10.1016-j.engstruct.2022.115151	-1		Shape memory alloys (SMAs) are smart materials with self-centering characteristics that can be used to reduce the earthquake damage to structures. In this paper, the optimal thermal treatment to obtain the ideal mechanical properties of a CuAlBe SMA wires for seismic protection applications is discussed. For this purpose, the uniaxial cyclic and monotonic stress-strain response of a 1.4 mm-diameter wire subjected to heat treatments applied for different durations is evaluated. Wire specimens are tested in multiple environments at several strain amplitudes and loading protocols. The variation of mechanical properties over time is also addressed. Test results show that a minimum treatment time of 25 min at 750 degrees C (-200 mu m) is necessary for obtaining superelasticity at all ambient temperatures tested. Also, as the heat treatment time increases, the residual strain, functional fatigue, strength, energy dissipation and hysteresis degradation decrease, but the superelasticity limit and low cycle fatigue life are increased. However, a 35 min treatment (-400 mu m) causes the loops to become unstable at high temperatures and the training process is not efficient. The best conditions for seismic protection purposes are achieved with a 30 min treatment (-300 mu m), due to its maximum recoverable strain of 6.5 %, 3.6 % equivalent viscous damping, negligible residual strain and stable hysteresis under all temperatures evaluated and over time. A low-cycle fatigue model based on the Coffin -Manson relationship is also proposed.
10.1016-j.engstruct.2024.118708	-1		This study aims to the understanding of the impact of uncertainties related to constitutive model parameters on the cyclic response of CuAlBe Shape Memory Alloy (SMA) strands, and to define an adequate methodology for constructing the strands, thereby reducing uncertainty in their behavior. Employing a Bayesian framework and utilizing experimental data from tensile tests, the prior knowledge of mechanical properties at the wire level is updated. Various scenarios are explored, including model parameter updating for wires tested at different strain levels and from the same and different heat treatment batches. The updated model parameters are then used in a strand model, considering two scenarios: the strand is constructed from pieces cut from a single wire, post-heat treatment; or from pieces cut from wires from different heat treatment batches. The study concludes proposing a practical methodology to define test conditions for CuAlBe SMA wires and guidelines for the utilization of experimental data to predict bounds in the cyclic response of CuAlBe SMA strands.
10.1016-j.est.2019.100974	-1		The aim of this paper is to explore Cu-Mg metallic alloys with high thermal conductivity as intermediate/high-temperature Phase Change Materials (PCMs) for latent heat storage at Concentrated Solar Power plants (CSP). Two binary eutectic alloys Mg84Cu16 and Mg59Cu41 (at%) were investigated in terms of their structural, thermophysical and corrosion performance. In particular, homogeneity, eutectic composition, melting point, latent heat, specific heat, thermal diffusivity, thermal conductivity and density were investigated. Additionally corrosion tests were performed with common constriction materials like SS304 and SS316. The obtained results make magnesium-copper alloys one of the most promising materials for thermal energy storage application due to the highest thermal conductivity reported so far in 400-550 degrees C temperature range and their good thermal stability.
10.1016-j.est.2022.105069	5	materials; thermal; heat; properties; material; welding; sintering; fusion; strength; laser; heat sink; thermal conductivity; mechanical; sink; manufacturing	Metallic phase change materials enable energy storage at higher temperatures than sensible-molten nitrate salt energy storage concepts. The eutectic copper-magnesium alloy, Cu-67 wt% Mg, is an attractive phase change material due to its high thermal conductivity and melting temperature of approximately 490 degrees C, relevant for conventional power generation and many industrial processes. Thermophysical properties such as melting temperature, enthalpy of fusion, heat capacity in solid and liquid state and thermal conductivity has been carried out. The obtained results demonstrated a melting temperature in agreement with the calculated phase diagram as well as a high heat capacity and excellent thermal conductivity. Additionally, this work provides results of static reaction experiments of Cu-67 wt% Mg with the potential housing materials stainless steel SS304 and SS314, iron, alumina and graphite. The experimental results support the use of the Cu-67 wt% Mg alloy as phase change material in iron and graphite housings for thermal storage applications.
10.1016-j.est.2023.108258	-1		In this study, macro-encapsulated Cu-Si phase change materials (PCMs) by in situ alloying formation were successfully prepared for high temperature thermal energy storage. Cu and Si powders were mixed to obtain uniform Cu-Si powders, which were spherulitized into millimeter-size balls. The core balls were cladded with Al2O3 shells, and after the two-step sintering treatment, the Cu-Si@Al2O3 macrocapsules were successfully fabricated. Cu and Si powders were in situ smelted to form the Cu-Si alloys core PCM. The pores and gaps among the Cu and Si powders provided buffer spaces to accommodate the volume expansion of the PCM. The melting-solidification cycling test indicated that the Cu-Si macrocapsules were highly durable. The heat storage capacity of the capsules could be optimized by isostatic pressing to reduce excess cavities and by adding sintering aids to the Al2O3 shell to increase shell strength for forming larger size capsules with thinner shell thickness. The macrocapsules presented high heat storage capacity, for example, the Cu-20Si, 9 mm@1 mm-150 MPa capsule showed high values of 816 MJ/m3 and 198 J/g at a temperature range of 750-850 & DEG;C. The superior phase change properties and thermal cyclic durability demonstrated that that Cu-20Si alloy was more suitable for high temperature thermal storage applications.
10.1016-j.est.2025.115635	-1		Phase change materials (PCMs) offer tremendous potential in thermal management of high-power electronic devices (HPED). Solid-solid PCMs have become a powerful alternative to solid-liquid PCMs due to their incomparable advantages such as stable shape, no leakage risk, no corrosion, and long cycle life. However, intrinsic low thermal conductivity (18 Wm- 1 K- 1) impedes their practical application. Here, we report a class of Cu-Al-Ni PCMs exhibiting ultra-high thermal conductivity of 101 Wm- 1K- 1, and giant figure of merit of 5437 x 106J2K- 1s- 1m- 4, which is the highest value ever reported for all PCMs at working temperature (100-200 degrees C) of high-power electronic devices and 9 times than commercial PCMs. Furthermore, Cu-Al-Ni PCMs show adjustable phase transition temperature and excellent thermal cycle stability for applications at different operating temperatures. Thermal simulation also shows the significant heat dissipation effect for this PCM in thermal management of HPED. These unparalleled comprehensive properties provide Cu-Al-Ni PCMs with a high potential for use in the field of thermal management of HPED.
10.1016-j.eswa.2025.126770	-1		The machinability of copper-graphite (Cu-Gr) composites has gained significant attention due to their unique thermal, electrical, and mechanical properties. This study experimentally investigates the machinability performances (such as surface roughness, flank wear, cutting temperature, and energy consumption) of Cu-Gr hybrid composite materials during milling. It predicts these parameters with machine learning models. The study aims to contribute to sustainable and optimized manufacturing processes by analyzing the effects of different cutting parameters and cooling/lubrication conditions on this performance. Furthermore, advanced artificial intelligence-based models predict machining outcomes, providing a robust framework for process enhancement and industrial implementation. Although there are comprehensive studies on the machining performances of metal matrix composites in the literature, there is limited information on Cu-Gr composites' mechanical and thermal behaviors in milling processes. To address this deficiency, a full factorial experimental plan was applied on six different Cu-Gr composites and the effects of different cutting speeds, feed rates and cooling/ lubrication environments (Dry, MQL, cryogenic LN2) on flank wear, surface roughness, cutting temperature and energy consumption were analyzed. The materials used in the study were prepared by mixing graphite and hard phases (Al2O3 and Cr3C2) in specific proportions, and these composites were compared in terms of machinability. Afterward, the output parameters of the experimental results are predicted by employing the well-known machine learning models and the experimental results. The results manifested that Gradient-Boosted Decision Tree Regression performs better than the other ten machine learning models in predicting machinability parameters. Finally, this study highlights potential areas for future research and provides a practical guide for optimizing CuGr composites in manufacturing processes and achieving sustainability goals. It has engineering value in efficiency, cost reduction, and developing environmentally friendly applications, especially for the automotive, aerospace, and energy sectors.
10.1016-j.euromechsol.2003.10.001	4	transformation; martensite; martensitic; phase; shape; beta; memory; shape memory; temperature; temperatures; martensitic transformation; gamma; transformation temperatures; effect; thermal	Stress-induced martensitic transformations proceeding by the formation of internally faulted martensite plates are studied. The additional free energy associated with random stacking faults and the distinct elastic anisotropy of parent and product phases are accounted for in the micromechanical analysis of a thin plate-like inclusion of the martensite in the austenite matrix. The microstructure of the martensite plate is obtained as a solution of a constrained minimisation problem for load multiplier. The stress at which the transformation initiates and the predicted microstructure, i.e., plate orientation and the magnitude of shear induced by the stacking faults, depend on the stacking fault energy, loading direction and temperature. As an example, the microstructures are analysed in the 6M (M18R) martensite of a CuZnAl shape memory alloy.
10.1016-j.fluid.2006.10.003	12	thermodynamic; ternary; phase; data; experimental; equilibria; phase equilibria; liquid; binary; experimental data; calculated; phases; literature; model; calphad	Some Cu-based alloys, like Cu-Co, Cu-Fe and Cu-Co-Fe, display a liquid metastable miscibility gap. When the melt is undercooled below a certain temperature depending on the alloy composition, they present a separation in two liquid phases, followed by coagulation before dendritic solidification. In order to predict the phase equilibria and the mechanisms of microstructure formation, a determination of the metastable monotectics in the phase diagrams is essential. This paper focuses on the up-to-date findings on the Cu-Co, Cu-Fe and Cu-Co-Fe metastable miscibility gap in the liquid phase. Furthermore, the knowledge on the phase equilibria in the three systems is extended by presenting new results obtained by differential scanning calorimetry (DSC) and comparing them with the calculated phase diagrams.
10.1016-j.fluid.2019.03.003	12	thermodynamic; ternary; phase; data; experimental; equilibria; phase equilibria; liquid; binary; experimental data; calculated; phases; literature; model; calphad	The measurements of vapor-liquid equilibrium (VLE) for Cu-Bi and Cu-Bi-Sb alloys in vacuum distillation were performed. We calculated the VLE diagrams of Cu-Bi and Cu-Bi-Sb alloys at 10 Pa by Wilson equation only using binary parameters. Thermodynamic consistency tests of experimental data for the binary and ternary systems were discussed using the Van Ness method. The calculated results are in good agreement with the experimental data. The VLE data can be used for designing the purification process and phase separation of crude copper in vacuum metallurgy.
10.1016-j.fusengdes.2003.10.002	-1		A positron annihilation spectroscopy (PAS) based on positron lifetime measurements, Using the pulsed low energy positron system (PLEPS), is used to investigate defects create by hydrogen implantation and thermal treat of copper alloys. These alloys are designated for the use in the international thermonuclear experimental reactor (ITER). The results show that the changes in the microstructure of selected copper alloys (CuCrZr, CuAl25) depend strongly on the preparing technology of alloys as well as on the implantation dose experimentally simulating the neutron treatment. The full recovering of the structure after isochronal annealing in vacuum is observed in all implanted specimens at the temperature of 450 degreesC. Using the PLEPS technique, for the first time, depth profiling of the positron lifetime spectra in the near-surface region (20-500 nm) of hydrogen implanted copper alloys was performed and compared with the TRIM calculations and transmission electron microscopy (TEM) studies. Possible annihilation channels in CuCrZr and CuAl25 materials are discussed in details together with corresponding annihilation characteristics determined theoretically and using computer simulations. We discuss the results of positron lifetime measurements of the irradiated and non-irradiated CuZrCr and CuAl25 specimens. We identified the most probable types of positron trapping sites. Finally, the results are discussed in terms of microstructural changes of the studied materials upon irradiation and subsequent heat treatment.
10.1016-j.fusengdes.2009.01.075	-1		Copper alloys have been considered as a structural material for the heat sink substrate of a plasma-facing component (PFC) due to their excellent thermal conductivity. However, insufficient high temperature strength and large thermal expansion set the limitations to structural applications. Fiber-reinforced metal matrix composites (FRMMCs) can be a candidate for a structural material for the future PFCs due to the excellent high temperature strength . Since the FRMMCs of the PFCs are exposed to thermal and mechanical loads, the resulting stress fields in mesoscopic level are highly heterogeneous and often exceed the yield limit of the matrix. The shakedown limit was investigated as the safety criterion of the FRMMCs considering the fusion-relevant thermomechanical loads. In this work. the shakedown theorems were formulated with FEM and the large-scale nonlinear optimization program. The shakedown formulation was extended to three-dimensional models. The shakedown limits were determined for SiC fiber and Cu alloy FRMMC composite system. The stress and temperature loading paths of FRMMC components were determined in the fusion-relevant loading. The thermomechanical loading paths were compared with the shakedown limits. The results showed that the loading paths in the high heat flux (HHF) operation condition were partly covered by the area of shakedown limits. It was interpreted that the FRMMC layers may undergo low cycle fatigue.
10.1016-j.fusengdes.2011.01.085	5	materials; thermal; heat; properties; material; welding; sintering; fusion; strength; laser; heat sink; thermal conductivity; mechanical; sink; manufacturing	Due to their suitable thermal conductivity and strength, copper-based materials have been considered appropriate heat sinks for first wall panels in nuclear fusion devices. However, increased thermal conductivity and mechanical strength are demanded and the concept of property tailoring involved in the design of metal matrix composites advocates for the potential of nanodiamond dispersions in copper. Copper-nanodiamond composite materials can be produced by mechanical alloying followed by a consolidation operation. Yet, this powder metallurgy route poses several challenges: nanodiamond presents intrinsically difficult bonding with copper; contamination by milling media must be closely monitored; and full densification and microstructural homogeneity should be obtained with consolidation. The present line of work is aimed at an optimization of the processing conditions of Cu-nanodiamond composites. The challenges mentioned above have been addressed, respectively, by incorporating chromium in the matrix to form a stable carbide interlayer binding the two components; by assessing the contamination originating from the milling operation through particle-induced X-ray emission spectroscopy; and by comparing the densification obtained by spark plasma sintering with hot-extrusion data from previous studies.
10.1016-j.fusengdes.2015.06.180	6	grain; deformation; strain; strength; dislocation; cu-; tensile; size; ecap; grain size; sfe; ductility; hardening; high; stress	An ITER-grade Cu-Cr-Zr alloy was subjected to equal channel angular pressing (ECAP) at 400 degrees C via routes B-C and C, i.e. rotated 90 or 180 around the extrusion axis before subsequent passes. The microstructure of ECAP deformed samples showed shear bands confining small recrystallized grains of about similar to 0.2-1 mu m in size. The best mechanical properties were observed for sample ECAP processed via route Bc for which the density of shear bands is high and the interaction among them is notable.
10.1016-j.fusengdes.2016.02.070	-1		The present study investigates the effect of cryo-rolling process, i.e. cold-rolling at liquid-nitrogen temperature followed by heat treatment, on tensile properties of pure copper and precipitation-hardened CuCrZr alloy. The cryo-rolling process resulted in a simultaneous improvement of strength and ductility of pure copper. On the other hand, a cryo-rolled CuCrZr alloy showed higher tensile strength but comparable ductility with a conventional cold-rolled CuCrZr alloy. Microstructural analysis indicates that the drastically-beneficial effect of cryo-rolling on pure copper may be due to its heterogeneous size distribution of grains which consist of cryo-rolled fine grains, residual cryo-rolled grains and recrystallized coarse grains. The modest but certain benefit of cryo-rolling on CuCrZr alloy can be explained by different texture formation compared with conventional cold-rolling. Effect of neutron irradiation on tensile properties of cryo-rolled CuCrZr alloy is also examined.
10.1016-j.fusengdes.2017.01.017	-1		Full density Cu-1%Y and Cu-0.8%Y alloys have been produced by different powder metallurgy routes and subsequent hot isostatic pressing. Some of the alloys have been subjected to equal channel angular pressing (ECAP) via B-c route up to 8 passes. ECAP deformation homogenizes and refines the microstructure up to attaining a sub-micron grain structure. Thermal properties have been characterized by the laser flash method in the temperature range 373-773 K. The ECAP process, irrespective of the production route, enhanced the thermal conductivity to values similar to those for CuCrZr (ITER grade). The linear thermal expansion coefficient was temperature independent for all materials.
10.1016-j.fusengdes.2017.02.031	5	materials; thermal; heat; properties; material; welding; sintering; fusion; strength; laser; heat sink; thermal conductivity; mechanical; sink; manufacturing	For DEMO fusion reactor an expected heat flux of about 10MW/m(2) should be extracted by the divertor which will have, most likely, an armour part made of W and a following heat sink part made of Cu, or ODS Cu alloy. Unfortunately, for these materials the optimum operating temperature windows do not overlap. Thermal barrier materials are interface materials included in such components, aiming to keep the temperatures of both armour and heat sink parts in the corresponding operating windows, and to mitigate the effects of their different thermomechanical properties. Here we propose a simple spark plasma sintering route to create Cu-based composites with a high content (10-40 vol%) of various dispersed materials (Al or Y oxides, C, SiC), allowing a fine tuning of the content and a large pool of predefined shapes and dimensions. The resulting specimens can be further joined to armour and heatsink components via a similar electrical field assisted technology. Micro-structural and thermal properties are investigated for these materials allowing to select the most suited materials in view of their thermal conductivity and thermal expansion coefficients. (C) 2017 The Authors. Published by Elsevier B.V.
10.1016-j.fusengdes.2017.04.062	-1		In this study, mechanical properties of Dispersion Strengthened (DS)-Cu-Al (aluminum) and Zr (zirconium) alloys, which were fabricated by an MA-HIP method, were investigated for application to the heat sink materials of fusion reactors. The effect of air exposure before the HIP process was studied using a NIFS-Sealing Device. Cu-Al specimen with air exposure before HIP was broken during wire-electrical discharge formation. Cu-Al specimen without air exposure exhibited high fracture strength, but without yielding. Cu-Zr specimen, both with and without the exposure, yielded and exhibits elongation. An increase in yield and tensile strength by approximately 61% and 45%, respectively, were obtained for Cu-Zr specimen by avoiding air exposure. The results showed that Cu-Zr specimen is less susceptible to the atmosphere of the MA-HIP process than Cu-Al.
10.1016-j.fusengdes.2017.05.083	4	transformation; martensite; martensitic; phase; shape; beta; memory; shape memory; temperature; temperatures; martensitic transformation; gamma; transformation temperatures; effect; thermal	A low temperature metallographic in-situ observation apparatus was designed to research the martensitic phase transformation of Cu-Al-Mn cryogenic shape memory alloy. Some martensitic transformation rules were summarized. In the processing of martensite phase transition, martensite grains gradually grow up as the temperature decreases and shrink as warming up. Many martensites phase with different orientation formed in a grain (self-accommodation of martensite variants). The result also suggested an interaction between martensites. Appearance of a new martensite will make another martensite disappear. When continue cooling the sample, the martensite which is disappeared will reappear. The nucleation site of martensite can be everywhere. However, nucleation rate in the grain boundaries and sample boundaries is higher than that of other sites. Martensites can grow cross the grain boundaries into another grain. The crossing point can be a new nucleation point. (C) 2017 Published by Elsevier B.V.
10.1016-j.fusengdes.2018.01.011	5	materials; thermal; heat; properties; material; welding; sintering; fusion; strength; laser; heat sink; thermal conductivity; mechanical; sink; manufacturing	DEMO fusion reactor divertor is expected to extract a heat flux of about 10 MW/m(2). One of the most promising concept design for it is the W-monoblock, which should be connected to a CuCrZr or an advanced Cu ODS alloy pipe passing through the W component. Since the optimum operating temperature windows for W and existing Cu alloys are far away from overlapping, a suited interface is needed to keep the adjacent materials as close as Possible to their respective temperature operating windows. The interface material should therefore have a low enough thermal conductivity to act as a thermal barrier and a thermal expansion coefficient suited to protect the W-pipe joint from stresses induced by the different thermo-mechanical properties of W and Cu-alloys. As interface materials we have considered Cu-ZrO2 composites produced by powder metallurgy route. Such materials can be realized in an unexpected large compositional range (up to at least 90% ZrO2 volume concentration) and be easily further joined to both W and Cu-alloys by an electrical field assisted technology. We analyse their microstructure and thermo-physical properties both as single materials and included in W-thermal barrier-CuCrZr 3-layers systems in comparison to those of previously produced Cu-ased composites and commercially available Cu foams.
10.1016-j.fusengdes.2018.01.076	-1		Plasma vertical stabilization is a serious concern during Tokamak operation, which may cause melting of in vessel components. To improve the vertical stability of plasma, pure copper layer/cladding of 3 mm-thickness has been recommended. Owing to this large thickness, development of such coatings is a challenging task. In this work, Cu-claddings of thickness 1 mm and 3 mm were developed using copper powder of particle sizes < 63 mu m and > 63 mu m respectively by laser cladding process on an in-vessel component material (SS316L). The deposited claddings were characterized by X-ray diffraction (XRD) and X-ray radiography analysis. The cross-sectional microstructure of both the claddings was characterized with the help of scanning electron microscope (SEM) and optical microscope (OM). Various mechanical properties such as micro-hardness, tensile strength, % elongation, adhesion strength, yield strength, Young's modulus, nano hardness and density were evaluated for both the claddings and compared. Hardening was observed along the interface and HAZ of the cladded steel, which may be attributed to the diffusion of carbon from the substrate. Results of the study indicate that laser cladding could be a feasible solution to develop claddings for advanced fusion reactors, as well as, for manufacturing copper cast iron canisters; however, further improvements in the properties need to be done by further refining the process parameters.
10.1016-j.fusengdes.2018.10.004	-1		Studies related to butt welding of precipitation hardened (PH) Cu-Cr-Zr alloy plates using electron beam were carried out. Significant reductions in strength and microhardness were observed for all no-aged electron beam welded joints. The microstructural studies of fusion zone of the welded samples were analyzed in order to understand the reasons behind their loss of micro-hardness and tensile strength . Precipitation behaviors of different zones were also studied using X-ray Diffraction (XRD), Energy Dispersive X-ray Spectrometry (EDS) and transmission electron microscopy (TEM). All the metallurgical studies indicated reduction of precipitate and intermetallic density in the fusion zone of the weld. In addition to that, the effects of process parameters, namely accelerating voltage, beam current and welding speed, were studied on the responses, such as micro-hardness and tensile strength of the welded sample. A set of optimal input parameters was also determined in order to obtain the maximum microhardness and tensile strength . Fractographic analyses of the joints were carried out to study the failure behavior of the butt-welded specimens.
10.1016-j.fusengdes.2018.11.058	6	grain; deformation; strain; strength; dislocation; cu-; tensile; size; ecap; grain size; sfe; ductility; hardening; high; stress	Dispersion strengthened Cu-1%Y (wt%) has been produced by mechanical alloying and subsequent consolidation by hot isostatic pressing (HIP). Samples of this alloy have been submitted to an equal channel angular pressing (ECAP) process and the effects on the microstructure and mechanical properties analyzed. The characteristics of the microstructure, such as the size distributions of both, the grains and Y-rich particles dispersed in the Cu matrix, have been studied by high resolution electron scanning microscopy and electron backscatter diffraction. The as-HIP alloy exhibits a quasi-bimodal distribution with an average diameter of 17 +/- 14 mu m. The ECAP treatment refines the average grain size to 1.3 +/- 0.9 mu m besides changing the size distribution of the Y-rich particles, which shifted from average size from 94 +/- 9 nm to 55 +/- 8 nm after ECAP. The mechanical characteristics have been investigated by means of microhardness measurements, and stress-strain tests in the temperature range 293-573 K. The ECAP deformation resulted in an increase of the mechanical strength and a decrease in ductility. It is found that the Voce law can satisfactorily describe the plastic and hardening rate behavior of these alloys. The strain hardening rate plots as a function of flow stress for the samples tested at 293 <= T <= 773 K exhibited a two-stage behavior, comprising a transient stage at low stresses followed by the characteristic linear dependence for the stage III of hardening in f.c.c. metals.
10.1016-j.fusengdes.2019.01.133	-1		Fabricating high-strength copper (Cu) alloys with high conductivity are extremely desirable for a range of applications, such as heat sink materials in fusion reactors. This study reports an in-situ mechanochemical process combining Mechanical Alloying (MA) and Hot Isostatic Pressing (HIP) to prepare Cu-Y2O3 composites. It is found that MA of Cu and Y powders led to formation of a Cu(Y) solid solution, accompanied by lattice expansion, grain refinement, melting point decline, and hardness increase. When the Cu(Y) solid solution powder was milled with CuO powder, reaction between Cu(Y) and CuO occurred, with a shrinkage of the lattice, and increase in both the melting point and hardness. The MA powder was then consolidated by HIP, and the existence of Y2O3 was confirmed by X-ray diffraction. An unexpected decrease of the electrical conductivity of the consolidated bulk material was observed and the reason was analyzed. This study will provide helpful information to optimize the preparation of copper-based materials through process control.
10.1016-j.fusengdes.2019.03.027	-1		In our previous work, the joint between oxide dispersion strengthened copper alloy (ODS-Cu), GlidCop (R) (Cu-0.3 wt%Al2O3) and tungsten (W) demonstrated superior fracture strength (similar to 200 MPa). This joint was fabricated by the direct brazing method between W and ODS-Cu using BNi-6 (Ni-11%P) filler material without any intermediate layer. This method was named as the improved or the advanced brazing technique. In the present study, deformation and fracture behavior of the joint after the three-point bending test was investigated. At first, it was found that the crack initiation points were dominantly in the W bulk, although it was not clear that the crack initiated from grain boundary or not. Secondly, the crack propagation proceeded mostly in the W bulk but tended to deflect towards the bonding layer. These results interpret the strength of the bonding interface is superior and the present bonding technique is applicable for severe environments such as a high heat flux divertor component on the fusion reactor. Based on the above physical and technological understanding, we successfully fabricated the large scale divertor mock-up which has twenty-eight plates of W with each size of 20 x 20 x 5 mm(3).
10.1016-j.fusengdes.2019.03.044	-1		In this study, CuxCrFeTiV (x = 0.21, 0.44, 1 and 1.7 M ratio) high entropy alloys have been devised for thermal barriers between the plasma facing tungsten tiles and the copper-based heat sink in the first wall of nuclear fusion reactors. The high entropy alloys were produced by ball milling the elemental powders, followed by consolidation with spark plasma sintering. Irradiation of the equiatomic CuCrFeTiV sample was carried out at room temperature with Ai(+) (300 keV) beams with a fluence of 3 x 10(20) at/m(2). Structural changes prior and after irradiation were investigated by scanning electron microscopy, coupled with energy dispersive X-ray spectroscopy, X-ray diffraction and thermal diffusivity. Preliminary results showed the presence of heterogenous and multiphasic microstructures in all samples. Moreover, with the increase of the Cu content it is possible to observe the formation of Cu-rich structures. The diffractogram of the CuCrFeTiV sample revealed major peaks of a BCC crystal structure and minor peaks of a FCC crystal structure. In addition, after irradiation no modifications in the CuCrFeTiV microstructure or in the diffractogram were observed.
10.1016-j.fusengdes.2019.111269	-1		We approached the solid solution strength process for the high mechanical strength bronze processed Nb3Sn wires by the internal matrix reinforcement. Previously, we already reported the mechanical strength improvement of the Nb3Sn wire by the increasing of the amount of Zn element composition of the Cu-Sn-Zn ternary alloy matrix. However, there was also a trade-off relationship between the Sn and Zn compositions of the ternary matrix on the mechanical strength and superconducting properties. A Cu-Sn system ternary alloy containing Indium (In) element as a solute element (Cu-Sn-In), which is thought to be more effective solute element compared with Zn, was casted in order to improve mechanical strength beyond Cu-Sn-Zn ternary alloy matrix samples on the solid solution strength process. We fabricated various Cu-Sn-In-(Ti)/Nb precursor wires having 19 Nb multicores. The In element remained in the matrix after the Nb3Sn synthesis through the diffusion reaction, and then the Vickers hardness of the Cu-Sn-In matrices after the Nb3Sn synthesis heat treatment was higher than that of the conventional bronze and Cu-Sn-Zn matrices. We also confirmed that critical current density (J(c)) property of the Nb3Sn wires using Cu-Sn-In-(Ti) was drastically increased at low and middle magnetic field below 15 T. These suggested that the In solute element in the matrix contributed the solid solution strengthening of the matrix after Nb3Sn synthesis and also improve J(c)-B performance.
10.1016-j.fusengdes.2020.111766	-1		Microstructure evolutions and properties variations of a high-strength Cu-Ni-Si alloy during multidirectional forging have been systematically investigated using microstructure characterizations and properties measurements. Experiment results indicated that nano-scale grains formed in the block samples having been multidirectional forged (MDF) at room/cryogenic temperatures. With the increase of the MDF cycle, the sub-grain structure was further refined to nano-grains with tens of nanometers in diameter. The ultimate tensile strength of the cryogenic temperature multidirectional forged sample was 1057 MPa, the yield strength was 923 MPa, and the fracture elongation was 7.2%. Rather than the solid solution strengthening from solutes impeding the glide of dislocation motion and the second phase particle precipitation strengthening from the Orowan looping, the grain boundary strengthening from the Hall-Petch effects plays crucial roles in strengthening the samples having been cryogenic multidirectional forged. These findings indicated that multidirectional forging is a passport to an ultrafine-grained structure and high yield strength material for the nuclear industry.
10.1016-j.fusengdes.2020.111852	-1		In order to improve the high-temperature stability of copper (Cu) alloys, which have a range of applications because of their high conductivity, an in-situ mechanochemical process based on Mechanical Alloying (MA) and Hot Isostatic Pressing (HIP) was proposed and Cu-Y2O3 alloys were prepared. An interesting mull-modal distribution of particle size was observed in the high yttria (3/ 5 wt%) doped MA powders. Understanding the mechanism behind the above phenomenon will be important for preparing ODS-Cu by MA process. Thus, this paper investigates the formation of mull-modal distribution of particle size in the Cu-Y-CuO system. It was found that the finer the powder, the larger its lattice parameter, hardness, and oxygen content will be. On the basis of these data and the microstructural evolution of the powders with MA time, it was suggested that after CuO powder is mixed with Cu-Y alloyed powder, the high energy ball-milling will induce the formation of a hard and brittle O-rich shell on the surface of Cu-Y particles. With the continuing of MA, the high-energy collision between the balls will make the hard/brittle O-rich layer break into pieces. These results can provide helpful information to optimize the preparation of copper-based materials through process control.
10.1016-j.fusengdes.2020.111962	-1		Friction stir processing (FSP), a solid-state materials processing technique, is an effective method to modify the surface properties of metallic materials. In the present study, an effort has been made to improve the hardness and wear resistance of Cu-0.62 %Cr-0.11 %Zr alloy through FSP. Single-pass friction stirring was carried out by fixing the tool rotational speed as 600 rpm and by varying the tool traverse speed from 50 to 200 mm/min in steps of 50 mm/min. Samples were extracted from the stir-zone regime to characterize their microstructure, hardness, wear-resistance and electrical conductivity. It is observed that with an increase in tool traverse speed, the grain size of the stir zone decreases from 38 mu m to 5 mu m. At the same time, the Vicker's hardness of the friction stir processed samples improved from initial 71VHN to 95VHN. A significant reduction in the coefficient of friction (CoF) noted after processing, and it continuously decreased from 0.4 to 0.12 as traverse speed increased. Consequently, the wear rate of the processed samples gradually decreased as traverse speed increased. The peak shift seen in X-ray patterns of processed specimens suggested the presence of residual strain in the processed zone. The electrical conductivity was measured applying the eddy current method. Conductivity decreased from 84 %IACS to 81.5 %IACS. Hence, the intent of improving the wear resistance and hardness of the Cu-Cr-Zr alloy attained without deteriorating the electrical conductivity by FSP. The results suggest that FSP can be successfully used to enhance the wear and mechanical properties of the high strength and high electrical conductivity Cu-Cr-Zr alloys.
10.1016-j.fusengdes.2020.112045	-1		A copper-based material is the recent main trend of advanced heat sink materials for the solid divertor systems, providing an optimal combination of excellent mechanical strength and superior thermal conductivity under severe neutron irradiation environment. In particular, oxide dispersion strengthened Cu (ODS-Cu) alloy with yttrium oxide (Y2O3) nano-particles is one of the promising materials because of the lower influence of the particles on thermal conductivity and the higher resistance to coarsening of the particles due to their thermodynamic stability. The metal Y as the Y2O3 source has been used to fabricate ODS-Cu alloys in the previous work. In this study, we used the Cu6Y intermetallic compound as the new Y source material to form Y2O3 particles during mechanical alloying (MA) followed by hot isostatic pressing (HIP) process, and successfully fabricated ODS-Cu alloy with Y2O3 nano-particles using the Cu6Y compound. The effects of Cu2O addition in this process as the oxidant material were also investigated. Y2O3 nano-particles with typical size of 30 nm were successfully formed into the Cu intra-grains and around grain boundaries, and the density of the Y2O3 nano-particles increased by the Cu2O addition. Cu2O addition promoted the oxidation of Y from the Cu6Y compound, forming Y2O3 nano-particles.
10.1016-j.fusengdes.2020.112202	-1		Friction stir processing (FSP) is a solid-state material processing technique to enhance the surface properties of metallic materials. In this study, Cu-1.0%Cr alloy is friction stir processed with an intention to improve its surface hardness and wear resistance. A single-pass FSP was performed by varying the tool traverse speed from 50 to 200 mm/min in steps of 50 mm/min and the tool rotational speed was kept constant at 600 rpm. Samples for microstructure, mechanical, electrical conductivity, and wear studies were extracted from the stir zone. The grain size of the stir zone was reduced to 4?m from its initial 40 ?m after processing with a traverse speed of 200 mm/min. An increase in hardness was observed in the stir zone processed with higher traverse speed (200 mm/ min) from 71 HV to 95 HV. The minimum wear rate and decrease in coefficient of friction (CoF) were observed in the specimen processed with 200 mm/min. The electrical conductivity of the base alloy was 84.4 % IACS, whereas for the processed at 50 mm/min alloy it was 82.1 % IACS. Results showed that FSP is an effective way to increase the wear resistance of the surfaces without much deteriorating the electrical conductivity.
10.1016-j.fusengdes.2021.112804	-1		Oxide dispersion strengthened Cu alloys (ODS-Cu) having dispersed yttria (Y2O3) fabricated using hot isostatic pressing (HIP) of mechanically alloyed (MA) Cu-Y powders. They exhibited a heterogeneous mixed grain structure, which were composed of a large and small Cu grain area. In the small Cu grain regions, Y2O3 particles were segregated along the grain boundaries, and acted as a crack propagation path, leading to brittle fracture. Therefore, we investigated the microstructural changes by the MA and heat treatment processes for the microstructure optimization. The powders of 4 to 32 MA hours formed a nested crust-like layered structure with large and small Cu grains. The layers were destroyed by heat treatment at 500 degrees C, because recrystallization and grain growth of Cu occurred in the temperature range of 310-330 degrees C. It was considered that Y2O3 was moved out to the circumferential area of the powders. Based on these results, it was suggested that the structural changes inside MA powders during HIP are the essential factor of the Y2O3 distribution within the Y2O3-added ODS-Cu alloys.
10.1016-j.fusengdes.2022.113061	-1		Cu, CuCrZr alloy and W are three typical materials used in the plasma-facing components of fusion reactors, whose mechanical properties vary significantly. The small punch test (SPT) is used to evaluate the mechanical properties for materials in the nuclear industry due to its advantage of requiring minimal sample volumes. In this paper, the correlation between SPT and uniaxial tensile testing (UTT) is investigated for Cu, CuCrZr alloy and W. From the views of mechanical properties and fracture morphologies, materials demonstrate consistent behaviours between SPT and UTT, which proves that the SPT is an effective method to characterize the mechanical properties and fracture mechanism of Cu, CuCrZr alloy and W. Moreover, the finite element simulation results of SPT for five other copper alloys with different mechanical properties are added to establish the correlation equations of mechanical properties between SPT and UTT. One unified correlation equation between SPT and UTT can be established for the ductile materials, even if with largely different mechanical properties. However, the introduction of a brittle material W invalidates the correlation equation. This work provides a prospect of SPT to study the mechanical properties of materials used in plasma-facing components.
10.1016-j.fusengdes.2022.113157	-1		Copper alloys are among the most promising candidate materials for divertor heat sinks owing to their remarkable advantages. However, it is challenging to use CuCrZr alloys as heat sink materials because of the harsh loading environment expected for plasma-facing components (PFCs) in future fusion reactors. Explosive welding is an effective method for manufacturing high-quality oxide dispersion strengthened copper (ODS-Cu) / 316 L stainless steel (SS) clad plates. Non-destructive testing results revealed a soundness bonding interface between ODS-Cu and 316 L without any detectable defects or cracks. In this study, optical microscopy and scanning electron microscope analysis revealed that the bonding interface did not contain any cavities and a typical wave-bonding morphology was observed. Moreover, the tensile stress of the bonding interface was higher than that of the ODS-Cu parent metal, and there was an increment in hardness on both sides near the bonding interface. The helium leak testing results indicate that the welded ODS-Cu / 316 L exhibits soundness without deformation or leakage at cyclic room and high temperatures. The results prove that the explosive welding method is a practical method for manufacturing high-quality ODS-Cu / 316 L clad plate that meet the design requirements and can provide critical references for the engineering design of the China Fusion Engineering Test Reactor (CFETR) divertor heat sink.
10.1016-j.fusengdes.2023.114011	5	materials; thermal; heat; properties; material; welding; sintering; fusion; strength; laser; heat sink; thermal conductivity; mechanical; sink; manufacturing	In fusion devices, the actively cooled W-monoblocks of the PFUs (Plasma Facing Units) are installed in the divertor to protect the vacuum vessel and magnets against neutron flux in the bottom region of the vessel. Copper alloy is considered to be the ideal heat sink material due to its high thermal conductivity and sufficient mechanical strength, in which ODS (oxide dispersion-strengthened)-Cu is selected as a candidate. With the increasing of operating parameters, such as higher heat flux (-20 MW/m2, H-mode) and longer pulse (up to 2.00 h) in EU-DEMO [1], the heat sink structure will undergo thermal creep induced by high temperature, stress and long holding time, which accelerates fatigue failure and could potentially be a very critical issue for the long-term safe operation of the fusion reactor. In this paper, an ITER-like monoblock with ODS-Cu as heat sink was studied for its creep fatigue life under DEMO operation conditions. The temperature distribution and stress/strain results of ODS-Cu were determined using finite element analysis. The investigation shows that high temperature creep occurs at the heat sink. Based on a damage accumulation model, the predicted life of the PFUs for the divertor are investigated at different operating modes. The analysis provides theoretical feasibility for selecting ODS-Cu as a heat sink material. The effect of stress relaxation on creep behavior during thermal stress cycle was also demonstrated and this was compared with the same for CuCrZr.
10.1016-j.heliyon.2019.e02058	2	corrosion; surface; film; electrochemical; films; spectroscopy; layer; current; solution; potential; resistance; composition; x-ray; ions; showed	In this work, the effect of the nature of the salt anion (chloride and sulphate) in the Cu-Zn citrate bath was investigated, using cyclic voltammetry (CV) and chronoamperometry (CA). Experimental electrodeposition parameters (switching potential and imposed potential) were varied in order to examine their influence on the deposits. The coating microstructures were observed by scanning electron microscope (SEM-EDS), the coating phases were characterized by X-ray diffraction (XRD) analysis and the surface composition was assessed by XPS. Higher current efficiency was obtained in chloride baths compared to sulphate baths and best deposits were obtained at -1.4 V vs. (Ag/AgCl/KCl) compared to -1.2 and -1.5 V vs. (Ag/AgCl/KCl). Corrosion test results in 0.5 M NaCl solution show that Cu-Zn deposit produced from chloride bath exhibited the highest corrosion resistance.
10.1016-j.heliyon.2019.e02471	-1		The main objective of this research is to explore the influence of trace additions of titanium on grain characteristics (morphology and size), conductivity, and mechanical properties of copper-silicon-titanium alloys. The alloys compositions were designed using response surface optimal design (RSOD). The designed alloy compositions were melted, cast, and subjected to normalizing heat treatment at 900 degrees C for 0.5 hr. The grain characteristics and the elemental constituents of the produced alloys were analyzed using an optical microscope (OM), scanning electron microscopy (SEM), and x-ray fluorescence spectroscopy. The average grain size and distribution were also determined. The properties investigated were percentage elongation, tensile strength, hardness, electrical conductivity, and density. The results were analyzed statistically using analysis of variance (ANOVA) to obtain the significance of titanium content on the tested properties and to generate statistical model equations for future applications. The experimental results were optimized to ascertain the optimal alloy composition and properties. The OM and SEM results revealed a decrease in the average grain size of the parent alloy (Cu-3Si) from approximate to 10.1 mu m to approximate to 4.4 mu m and change in grain morphology after adding titanium, leading to improvement of properties. The results were confirmed to be statistically significant. The optimization results revealed Cu-3Si-0.47wt%Ti as the optimal alloy composition.
10.1016-j.heliyon.2020.e04674	12	thermodynamic; ternary; phase; data; experimental; equilibria; phase equilibria; liquid; binary; experimental data; calculated; phases; literature; model; calphad	The surface tension and viscosity of Cu-Fe-Si ternary alloys were computed at different temperatures using thermodynamic approaches. The thermodynamic data of the alloy were optimized in the framework of the Redlich-Kister (R-K) polynomials and exponential temperature dependent coefficients of the R-K polynomial were obtained. These coefficients were used to compute the excess Gibbs free energy of mixing of the alloy and the partial excess free energy of the components. The partial excess free energy so obtained was used to compute the surface tension of the ternary Cu-Fe-Si alloy system and its binary sub-systems. The enthalpy of mixing was also optimized and it was used to compute the viscosity of the sub-binary and ternary alloys.
10.1016-j.heliyon.2023.e18781	-1		In this paper, we explore the surface and mechanical alterations of Cu, as well as the parameters of laser-assisted plasma and ablation. The irradiation source is a Nd: YAG laser with a constant irradiance of 1.0 GW/cm2 (1064 nm, 55 mJ, 10 ns, 10 Hz). Physical parameters such as electron temperature (Te) and electron number density (ne), sputtering yield (yield), ablation depth (depth), surface morphology (morphology), and hardness (Vickers) of laser irradiated Cu are evaluated using instruments such as a Laser Induced Breakdown Spectrometer (LIBS), Quartz Crystal Microbalance (QCM), Optical Emission Microscope (OEM), Scanning Electron Microscope (SEM), and Vicker's hardness tester. These physical characteristics have been studied in relation to changes in pressure (from 10 torr to 100 torr) and the composition of two inert ambient gases (Argon and Neon). Pressures of Ar and Ne are found to enhance the emission intensities of spectral lines of Cu, Te, and ne, as well as the sputtering yield, crater depth, and hardness of laser ablated Cu, to a maximum at 60 torr, after which they decrease with subsequent increases in pressure up to 100 torr. Increases in pressure up to 60 torr are connected with plasma confinement effects and increased collisional frequency, whereas decreases in pressure between 60 and 100 torr are ascribed to shielding effects by the plasma plume. All numbers are also found to be greater in Ar compared to Ne. In Ar, laser-ablated Cu reaches a maximum of 15218 K, 1.83 x 1018 cm-3, 8.59 x 1015 atoms/pulse, 231 m, and 147 HV, whereas in Ne, it reaches a maximum of 12000 K, 1.75 x 1018 cm-3, 7.70 x 1015 atoms/pulse, 200 m, and 116 HV. Ar is more likely than Ne to develop surface features such as craters, distinct melting pools with elevating edges, flakes, cones, etc. It is also shown that there is a significant association between the outcomes, with an increase in Te and ne being responsible for a rise in sputtering yield, ablation depth, surface morphology, and surface hardness. These findings have potential uses in plasma spectroscopy for materials science and in industrial applications of Cu.
10.1016-j.ibiod.2024.105762	2	corrosion; surface; film; electrochemical; films; spectroscopy; layer; current; solution; potential; resistance; composition; x-ray; ions; showed	Currently, the microbiologically influenced corrosion (MIC) of 90/10 copper-nickel (Cu-Ni) has garnered increased attention. Pseudomonas aeruginosa, a prevalent nitrate-reducing bacteria in seawater, is a notable participant in the process of marine nitrogen cycle. This study seeks to investigate the impact of NH4+ on the corrosion process of 90/10 Cu-Ni alloy in the P. aeruginosa media. The results revealed that the average pit depth of the alloy coupons was 4.4 +/- 0.2 mu m in the P. aeruginosa media, whereas the average pit depth reduced to 2.8 +/- 0.1 mu m in the P. aeruginosa + NH4+ media. In the P. aeruginosa media, the corrosion current density (icorr) was 4.96 x 10-7 A cm -2, while in the P. aeruginosa + NH4+ media, the icorr decreased to 2.45 x 10-7 A cm -2. The excess NH4+ led to a reduction in the P. aeruginosa biofilm thickness (23.4 mu m vs. 35.6 mu m), facilitated the underlying P. aeruginosa sessile cells to obtain energy from free organic carbon more easily. Additionally, the interaction of Cu with NH3 led to the formation of the unstable complex Cu(NH3)2 +, ultimately resulting in the formation of a protective Cu2O layer on the alloy surface, thus mitigating the 90/10 Cu-Ni alloy MIC.
10.1016-j.icheatmasstransfer.2019.104414	-1		Nonuniform temperature field at cross section of profiled billets during conventional continuous casting always results in serious defects and inhomogeneous microstructures. In this paper, a 3D temperature controlled mold continuous casting (TCMCC) model for preparing profiled copper strip was established and verified to calculate the magnetic and temperature field during continuous casting process. Under different controlled temperatures of TCM and casting speeds, the temperature fields in the TCM and melt were numerically calculated, and the variation of temperature fields in the mushy zone was analyzed. The calculated temperatures are in good agreement with the measured values. The results indicate the uniformity of temperature gradient (u(G)) at the profiled section improves significantly when the controlled temperature of TCM is higher than the liquidus temperature of alloy, further, the u(G) gradually reaches the minimum and then increases with increasing casting speed. Based on the calculated results, the profiled KFC copper alloy strips with good surface quality were successfully prepared by the TCMCC under controlled TCM temperature of 1423 K and casting speeds of 15-60 mm/min. The value of the uniformity of primary dendrite spacing at the cross section of the profiled strips reaches the minimum with the casting speed of 45 mm/min.
10.1016-j.ijbiomac.2025.144822	2	corrosion; surface; film; electrochemical; films; spectroscopy; layer; current; solution; potential; resistance; composition; x-ray; ions; showed	This work aims to evaluate the potential of the aqueous extract of Ammi visnaga (L.) Lam (AE-AV) as a corrosion inhibitor for Cu-Zn alloy in a 3 % NaCl solution, using both experimental and computational approaches The chemical composition of AE-AV was examined using UV-visible and FTIR spectroscopy, revealing a significant concentration of lignin (G/S type) in this extract. The corrosion inhibition efficacy of AE-AV was evaluated using electrochemical methods such as potentiodynamic polarization (PDP) and electrochemical impedance spectroscopy (EIS). According to the PDP study, AE-AV acts as a mixed-type inhibitor with a dominant cathodic action. The EIS results showed that greater AE-AV concentrations and longer immersion time enhanced inhibitory effectiveness, with a maximum of around 91.67 % at 1000 ppm AE-AV after 48 h of immersion. Moreover, surface morphology analysis using SEM and EDX demonstrated that AE-AV compounds form a protective barrier layer on the alloy surface. Quantum mechanics chemistry, using the Dmol3/PBE/DNP+ level of theory, provided vital information on the electronic characteristics of the lignin (G/S type) biopolymer, particularly its capacity to supply and take electrons, allowing for effective adsorption onto the Cu-Zn surface. Furthermore, molecular dynamics (MD) simulations were utilized to investigate the interactions of lignin fragments with various Cu-Zn surfaces. The findings demonstrated the effectiveness of lignin (G/S type) as a corrosion inhibitor, with longer lignin chains having more interactions with Cu-Zn surfaces. This study offers novel insights into the molecular profile of an aqueous extract from Moroccan Ammi visnaga (L.) Lam and reveals the inhibitory effect of lignin (G/ S type).
10.1016-j.ijfatigue.2005.08.014	-1		The objectives of the present study were to assess and to optimize the fatigue behaviour in strain-controlled tests of different ultrafine-grained (UFG) metals and alloys (Cu, Al, AA6061, alpha-brass) prepared by equal channel angular pressing (ECAP). Quite generally, the UFG materials investigated exhibited shorter fatigue lives in the low-cycle fatigue (LCF) regime than corresponding conventional grain (CG) size specimens. In all cases, the fatigue lives could be enhanced appreciably by a suitable heat treatment following ECAP without, however, paralleling the fatigue lives of the CG specimens. The microstructural reasons for this behaviour are discussed, and a microstructure-based fatigue life model for UFG materials is presented.
10.1016-j.ijfatigue.2016.01.004	6	grain; deformation; strain; strength; dislocation; cu-; tensile; size; ecap; grain size; sfe; ductility; hardening; high; stress	Fatigue tests were conducted on round-bar specimens to understand the fatigue behavior of precipitate strengthened Cu-6Ni-1.5Si alloy. Aging at 500 degrees C for 0.5 h produced delta-Ni2Si precipitates in the matrix, homogeneously and heterogeneously precipitated delta-Ni2Si particles, and a precipitate-free zone around the grain boundaries. The cracks were initiated at the grain boundaries, followed by growth along the crystallographic slip planes in the adjacent grains. Crack propagation from the crack origin along the grain boundaries was occasionally observed. The physical background of fatigue damage is discussed in light of the role of microstructure on the behavior of fatigue cracks.
10.1016-j.ijfatigue.2016.02.006	6	grain; deformation; strain; strength; dislocation; cu-; tensile; size; ecap; grain size; sfe; ductility; hardening; high; stress	The formation mechanism of inclined fatigue-cracks in ultrafine-grained Cu processed by equal channel angular pressing was studied by using a partially notched specimen in which a fatal natural crack was introduced, to a specific site of the smooth surface was feasible regardless of microstructural inhomogeneity caused by the processing. The crack growth direction depended on the location along the circumferential direction of the round bar specimen and on the applied stress amplitudes. The role of the Microstructure and deformation mode at the crack-tip areas on the formation behavior of fatal cracks is discussed in terms of the microstructural evolution caused by cyclic stressing and the mixed-mode stress intensity factor. The in-plane shear mode deformation at the crack tip assisted the formation of the inclined crack paths and the unique crack face profile.
10.1016-j.ijfatigue.2016.02.025	6	grain; deformation; strain; strength; dislocation; cu-; tensile; size; ecap; grain size; sfe; ductility; hardening; high; stress	This paper describes a characteristic damage propagation mechanism in low-cycle creep-fatigue of Cu-0.7Cr-0.09Zr (mass%), as investigated by creep-fatigue tests including strain controlled fatigue and stress-holding type creep, and following microstructural observations by scanning electron microscopy (SEM). The total stress-holding time until rupture in the creep-fatigue test was shorter than one-tenth of the rupture life in the simple creep test, and the rupture life of the specimen in the creep-fatigue test was shorter than half of that in the simple fatigue test. The SEM images suggest that the connection between fatigue crack propagating along grain boundaries and intergranular creep voids rapidly accelerates crack propagation. Crown Copyright
10.1016-j.ijfatigue.2017.08.011	-1		Fatigue behavior of shape memory alloys depends on deformation mechanisms (e.g., martensitic transformation, variant conversion, slip, and elastic deformation) and how they interact with microstructure. In this paper, we examine fatigue properties of Cu-based shape memory alloys, focusing on the effect of strain accommodation at grain boundaries on fatigue life and fracture mode under various deformation mechanisms in polycrystals. Comparisons with single crystals and static test results are also made. As lack of plastic accommodation at grain boundaries often leads to brittle intergranular fracture, incorporation of a ductile intergranular phase is promising for providing strain accommodation for transformation nearby and improving superelastic fatigue life.
10.1016-j.ijfatigue.2018.06.017	-1		In this study, the tensile and fatigue tests were conducted on precipitate strengthened Cu-Ni-Si alloy. The fatigue properties of specimens with cold working and without cold working in air, as well as that of the specimen with cold working in salt atmosphere were investigated. The results show that the monotonic tensile strength and the yield strength are improved obviously, while the elongation decreases by cold working. The S-N curves of all the types of specimens show a continuous decrease. The fatigue strength of specimens in air is slightly reduced by cold working, however, that of the specimen with cold working at 107 cycles is largely decreased from 190 MPa to 120 MPa in salt atmosphere. All the fatigue cracks initiate from the specimen surface by slip deformation. In air condition, the specimens with cold working show shear mode fracture with transgranular crack propagation and it is caused by the obvious texture, while that without cold working show normal mode fracture with both transgranular and intergranular crack propagation. However, in salt atmosphere condition, the specimens with cold working show normal mode fracture with totally intergranular crack propagation.
10.1016-j.ijfatigue.2018.06.027	6	grain; deformation; strain; strength; dislocation; cu-; tensile; size; ecap; grain size; sfe; ductility; hardening; high; stress	Creep-fatigue tests of Cu-0.7Cr-0.09Zr (mass%) alloy, which include stress-holding-type creep and strain-controlled fatigue, were conducted at elevated temperatures. A simple creep test was also carried out in order to compare the results with the results of the creep-fatigue test. The creep strains accumulated during creep deformation in creep-fatigue and simple creep tests were 310% and 12%, respectively. Such a large difference was due to the stacking of normal/inverse-transient creep in the creep-fatigue test. A dislocation cell structure smoothly developed in the simple creep test, whereas the cell intermittently developed in the creep-fatigue test because compressive plastic deformation immediately after creep partly broke apart the cell walls and prevented the cell structure from smoothly developing. Compressive stresses necessary for -1.5% strain were changed as cycling progressed in the creep-fatigue test. A much higher compressive stress would introduce a much higher dislocation density immediately before creep deformation. At the start of creep, these dislocations recovered and their number gradually decreased, which resulted in the appearance of inverse-transient creep.
10.1016-j.ijfatigue.2018.06.039	3	sma; shape; shape memory; memory; smas; superelastic; bars; damping; cu-al-mn; mechanical; bending; applications; numerical; sma bars; material	Due to their capability to recover the initial shape, Shape Memory Alloys (SMAs) are widely used in many applications. Different grades are commercially available and they can be classified considering either their chemical compositions (e.g., Cu based, Ni based, Fe based) or according to their mechanical behaviour. The most used SMAs are the Ni based alloys thanks to their performances both in terms of mechanical resistance and in terms of fatigue resistance, but their costs are quite high . Cu based alloys are good competitors of the Ni based alloys. The recent optimization of their chemical composition improved both the corrosion resistance in aggressive environments and their mechanical performances. In this work, the influence of the grain size on fatigue crack propagation in two Cu-Zn-Al SMAs has been investigated focusing on the damage micromechanisms.
10.1016-j.ijfatigue.2019.02.004	-1		Fatigue tests were conducted on round bar specimens of a solution-treated and air-cooled Cu-Ni-Si alloy with high solute concentrations of 6% Ni and 1.5% Si. This alloy was strengthened by disc-shaped Ni2Si precipitates, a few tens of nanometers in diameter, formed during air cooling. The results were compared with those of a conventional solution-treated Cu-Ni-Si alloy cooled by water quenching. The correlation between the tensile and fatigue strengths of the two alloys differed completely from the general tendency that enhanced tensile strength brings an increase in fatigue strength . Indeed, the fatigue strength of the air-cooled Cu-Ni-Si alloy was 1.1 times higher than that of the water-quenched alloy, while the tensile strength was only 75% that of the water quenched alloy. Moreover, the electrical conductivity of the air-cooled specimens in International Annealed Copper Standard (LACS) percentage points was 1.7 times higher than that of the water-quenched specimens. The physical background for the superior fatigue strength of the air-cooled Cu-Ni-Si alloy, including the role of microstructure, is discussed.
10.1016-j.ijfatigue.2019.105188	-1		The comparative low-cycle fatigue tests of the Cu/Nb nanocomposite wires obtained by the melt-and-deform method and pure copper samples were carried out using a dynamic mechanical analyzer (DMA). The fatigue tests were carried out using transverse bending scheme. It has been established that the fatigue fracture resistance characteristics of the Cu/Nb composites significantly higher as compared to that of pure copper samples. It has been found that the fatigue crack propagation in the Cu/Nb composites occurs at two scale levels. The effect of fatigue damage accumulation on the change in the electrical resistance of the Cu/Nb composites was studied.
10.1016-j.ijfatigue.2020.105642	-1		The low cycle fatigue behavior (Delta epsilon(t)/2 = 0.4-1.0%) of a Cu-Cr-Zr alloy strengthened with nanoscale precipitates has been tested at room temperature. The results showed that cyclic softening occurs under all Delta epsilon(t)/2 after cyclic hardening. However, the Cu-Cr-Zr alloy exhibited secondary cycle hardening after a brief softening at high Delta epsilon(t)/2 (0.8%, 1.0%). In strong contrast to the fatigue fracture surface at Delta epsilon(t)/2 = 0.4%, Delta epsilon(t)/2 = 1.0% was characterized by multiple fatigue sources and obvious fatigue striations. Moreover, a sawtooth-like feature formed and the fracture mode was mainly brittle with few regions of ductile aspects. Compared with the original characteristics, the microstructure after different values of Delta epsilon(t)/2( )was markedly different, and the dislocation density gradually increased with the increases of Delta epsilon(t)/2.
10.1016-j.ijfatigue.2024.108253	-1		In this study, we successfully fabricated large-scale bulk ultrafine-grained (UFG) Cu through friction stir additive manufacturing (FSAM) with or without subsequently cold rolling (CR). Despite high fatigue strength (130 MPa) were achieved in FSAM Cu, the subtle microstructural differences led to deformation inhomogeneity, and fatigue cracks initiated at the softer processing zone, leading to reduced fatigue life. By using appropriate CR to increase microstructural uniformity via introducing dislocations, the cyclic deformation uniformity of the FSAM + CR Cu can be effectively improved, significantly alleviating strain concentration and damage localization. Thereby, an overall improvement in fatigue strength and fatigue ratio (145 MPa and 0.31) and fatigue life were achieved in FSAM + CR Cu. It is anticipated that this work will provide a feasible strategy for fabrication large-scale bulk materials with excellent fatigue performance.
10.1016-j.ijfatigue.2024.108355	-1		The fatigue performance and microstructure of polycrystalline copper treated by one (UUV1), two (UUV2), three (UUV3) passes of unconstraint ultrasonic vibration (UUV) treatment were investigated in this paper. The surface roughness, fatigue life, microstructure, and plastic strain energy before and after UUV treatment were compared. The results revealed that the surface integrity of the sample for UUV treatment higher than that of the original sample, and the microscope observation found that the grain orientation, the dislocation density, the low angle grain boundaries, the plastic strain energy of the damaged sample restored to the original state to a great extent after UUV treatment. The fatigue crack initiation life increased by 3 times after UUV3 treatment.
10.1016-j.ijfatigue.2024.108731	-1		High-strength cast Cu alloys often contain substantial quantities of alloying elements that promote the nucleation of heterogeneous particles, particularly at grain boundaries (GBs). In the Cu-6Ni-1.3Si alloy, intermetallic compounds such as Ni2Si form within the matrix and along the GBs following homogenization. Ni2Si particles within the matrix are homogeneously nucleated with diameters of a few tens of nanometers, which enhances matrix strength . However, heterogeneously nucleated Ni2Si particles at GBs, which can be several micrometers in size, negatively impact overall strength . To improve the strength of Cu-6Ni-1.3Si alloy, 2.1 wt% Mn was added. This Mn addition led to the formation of plate- or film-shaped intermetallic compounds, specifically Ni16Si7Mn6 (G-phase), at GBs after homogenization. Despite the Mn addition, Ni2Si precipitates with diameters of a few tens of nanometers still formed within the grains, but these were more densely distributed in the Mn-added alloy compared to the Mn-free alloy. Fatigue tests conducted on round bar specimens of both alloys showed that Mn addition enhanced fatigue strength . This enhancement is attributed to the suppression of both crack initiation and propagation along the GBs and within the matrix.
10.1016-j.ijfatigue.2025.109282	14	strength; properties; conductivity; electrical; mechanical; cu-; grain; mpa; electrical conductivity; aging; precipitation; phase; mechanical properties; tensile; phases	Pure copper (Cu) and its composites are widely utilized in electrical, thermal, and structural applications due to their high conductivity and mechanical properties. However, improving fatigue resistance is essential for their long-term reliability. This study examines the low-cycle fatigue (LCF) and fatigue crack growth behavior of pure Cu, and a Cu-based metal matrix composite (MMC) reinforced with graphite (GP) and tantalum carbide (TaC). The Cu-GP-TaC MMC was fabricated by stir casting with a composition of 80% Cu, 10 % GP, and 10 % TaC by volume. Comparative mechanical assessments, including tensile testing, LCF analysis, and fatigue crack growth rate (FCGR) evaluation, reveal superior fatigue performance of the composite. EBSD characterization further confirms significant grain refinement, weakened texture intensity, and a predominance of high-angle grain boundaries (15 degrees-65 degrees) in the composite compared with pure Cu, all of which contribute to improved strength and fatigue resistance. The Cu-GP-TaC MMC exhibits higher tensile strength, enhanced strain life, and improved fatigue resistance across strain amplitudes (0.6 %-1.2 %) compared to pure Cu. S-N curve analysis indicates increased fatigue life and superior cyclic stress distribution. The composite also demonstrates greater strain hardening and higher plastic strain energy density at half-life cycles, contributing to an extended transition life. FCGR analysis confirms enhanced resistance to crack propagation under cyclic loading. Scanning electron microscopy (SEM) fractography reveals reduced crack initiation and propagation, attributed to the reinforcement's strengthening effect. These findings highlight the Cu-GP-TaC MMC's potential for high-performance structural applications, fatigue-resistant electrical contacts, and thermal management systems requiring enhanced mechanical reliability.
10.1016-j.ijhydene.2008.04.057	-1		Cr-nitride which offers good electrical conductivity and corrosion resistance was formed on the surface of Cu-5.3 (wt%)Cr alloy and its characteristic properties including electrochemical behavior and electrical conductivity were evaluated. The sample was annealed for 12 h in a temperature range of 600-1000 degrees C in a nitrogen atmosphere. Nitridation of Cr in Cu-5.3Cr alloy occurred at about 600 degrees C and followed Cr -> Cr2N -> CrN phase transformation sequence. A continuous Cr-nitride was formed at 1000 degrees C, but not below 900 degrees C. Corrosion behavior of the continuously nitrided sample was investigated in simulated PEMFC environments. Corrosion resistance of the nitrided sample was improved in an anode environment, but not in a cathode environment. This was attributed to the dissolution of Cu through pin-hole defects on the surface of the nitrided sample just in the cathode environment. Interfacial contact resistance of the nitrided Cu-5.3Cr alloy was satisfied the target value. Furthermore, there was no recession of electrical conductivity after polarization.
10.1016-j.ijhydene.2021.09.140	7	irradiation; shear; grain; ta; deformation; size; radiation; voids; nanocrystalline; simulations; similar; void; temperature; irradiated; boundaries	The effect of the Ni/Cu ratio on hydrogen embrittlement (HE) behavior is studied in the context of the Cu-Ni binary alloy system. When classifying HE sensitivity as a function of the Ni fraction, two regimes are obtained: Regime 1 (wherein Ni fraction is less than 80 wt%) with moderate HE and Regime 2 (where Ni fraction exceeds 80 wt%) with more severe HE, although hydrogen-(H-)induced intergranular (IG) cracking is noted to be the common primary cause of H-induced degradation. Necessities of H-transportation towards grain boundaries (GBs) via H-dislocation interaction and/or dynamic H-diffusion are discussed via the slow strain rate tensile tests at-196 degrees C. Specifically, in Regime 1, H-transportation is necessary for the triggering of IG cracking. Conversely, in Regime 2, such H -transportation plays a minor role and the initially concentrated hydrogen along GBs can sorely cause IG cracking.
10.1016-j.ijhydene.2025.05.159	-1		Copper (Cu) alloys are extensively utilized in naval architecture and ocean engineering applications, particularly in components such as propellers and seawater condensers. The synergistic interactions between solutes, vacancies, and hydrogen (H) significantly influence the mechanical and thermal properties of Cu alloys under extreme marine environments, including corrosion and H-induced damage. In this study, we investigated the diffusion behavior of H atoms from the Cu(111) surface into the bulk and their trapping mechanism by vacancies in Cu alloys using first-principles calculations combined with thermodynamic models. H atoms tend to be adsorbed at the hollow site on the Cu(111) surface, the migration barrier for H from the surface to the subsurface is relatively high with 0.73 eV, and the permeation mechanism of H diffusing from surface to bulk was obtained. Alloying nickel (Ni) and iron (Fe) promote the adsorption of H while aluminum (Al) inhibits it. Further, we obtained the mechanism of vacancy trapping for multiple H in pure Cu and Cu alloys. Mono-vacancy and di-vacancy can trap 6 and 10 H atoms, and H significantly reduces vacancy formation energy. The Ni-vacancy and Fe-vacancy complex can trap up to 10 H atoms, while Al-vacancy only traps 4 H atoms. Ni and Fe enhance the vacancy trapping ability for H atoms, in turn, vacancy increase the attraction of Ni and Fe to H atoms. The influence of the interaction between solute and vacancy on the H retention has been studied in detail. These findings deepen understanding of the H permeation process and solute effect on vacancy trapping H in Cu alloys.
10.1016-j.ijhydene.2025.06.179	14	strength; properties; conductivity; electrical; mechanical; cu-; grain; mpa; electrical conductivity; aging; precipitation; phase; mechanical properties; tensile; phases	Fatigue tests on Cu-Al-Ni-Fe-Mn cast alloys were conducted under hydrogen-free and hydrogen-precharged conditions. The hydrogen-precharged specimens were exposed to hydrogen gas at 100 MPa and 270 degrees C for 200 h to ensure a uniform hydrogen distribution. Rotating-bending fatigue tests were performed at 0.1-10 Hz at room temperature. Fractures consistently originated from casting defects, regardless of hydrogen charging. To isolate the defect's effect, an artificial defect was introduced. Hydrogen charging slightly extended the fatigue crack initiation life without accelerating the crack growth rate, resulting in a slight increase in total fatigue life. The fatigue limit was also marginally higher in hydrogen-precharged specimens. Although localized slip deformations induced by hydrogen were observed, their negative effects on fatigue properties were negligible. The dominant positive effect was attributed to increased hardness, while the overall impact on fatigue life remained slight, likely due to the low hydrogen content and the alloy's FCC structure.
10.1016-j.ijhydene.2025.150727	-1		Investigating the behavior of hydrogen (H) at grain boundaries (GBs) is essential for optimizing GB structures that improve the H embrittlement resistance in metals and alloys. In this study, first-principles calculations were performed to investigate the Ni/Fe/Al effect on H behaviors (solution, trapping, and diffusion) in three typical copper (Cu) GBs. H exhibits a lower solution energy with 0.20 and 0.23 eV at E5 (210) [001] and E9 (221) [110] GBs compared to the bulk, while it is higher at E3 (111) [110] GBs. Kinetically, E5 (210) [001] and E9 (221) [110] GBs not only act as fast H migration channels but also serve as trapping sites that promote H segregation from grain to GBs, whereas E3 (111) [110] GBs hinder H retention and diffusion. Thus increasing the E3 (111) [110] GB ratio in Cu can enhance H embrittlement resistance. The influence of solutes Ni, Al, and Fe at GBs on H stability is different, Ni and Fe act as a stabilizing effect by attracting H atoms with 0.17-0.41 eV. Compared to pure Cu GBs, Ni and Fe can reduce the migration barrier and solution energy of H at three GBs, promoting H diffusion from grains to GBs and its subsequent capture by Ni/Fe until saturation. In contrast, Al displays an opposite effect on the thermodynamic stability of H. Finally, the influence of solutes on GBs trapping for H was systematically discussed in comparison to other lattice defects. The computational results provide valuable information for understanding the retention and damage of H in Cu alloys.
10.1016-j.ijimpeng.2005.05.010	-1		Copper and copper aluminum (2 and 6 wt% Al) with orientations [001] and [134] were subjected to high intensity laser shocks (energy levels of 40-300 J; energy densities of 15-70 MJ/m(2) and durations below 10 ns). In situ X-ray diffraction and VISAR wave profile measurements were used to study the response of the lattice to the shock. Recovered samples were characterized by transmission electron microscopy in order to study the defects within the lattice. The results are rationalized in terms of a criterion in which slip and twinning are considered as competing mechanisms. The slip-twinning transition is determined quantitatively and predicted as a function of orientation, temperature, and stacking fault energy (determined by the Al content of the alloy). A constitutive description is applied to the two orientations and differing compositions, incorporating both slip and twinning in terms of orientation, stacking fault energy, temperature, and strain rate. The threshold stress is calculated, considering the effect of shock heating. The constitutive description provides calculated thresholds in pure copper: 18 GPa for [001] and 25 GPa for [134]. The experimentally determined threshold twinning stress for pure copper in the [001] orientation is 25 GPa, whereas the one for the [134] orientation is between 40 and 60 GPa. The predictions are in agreement with experiments. It also provides thresholds for the Cu-Al alloys. The growth of voids in incipient spalling is modeled by dislocation loop emission from the void surface. The first dislocation-based void growth mechanism, proposed by Lubarda et al [Acta Mat 2004; 52: 1397] is reviewed and extended to three dimensions. It has a generality rendering it applicable to a broad range of strain rates.
10.1016-j.ijleo.2022.169946	-1		Microchip laser-based spark-discharge assisted laser-induced breakdown spectroscopy (SD-LIBS) combined with one-point calibration (OPC) method was developed to realize quantitative elemental analysis of Cu-Zn-Ag alloy samples. OPC method makes it possible to use zinc atomic lines with unknown transition probabilities in the procedures of quantitative elemental analysis using a calibration-free algorithm. The relative errors of quantitative analysis of copper, zinc and silver in Cu-Zn-Ag alloy samples reached to 0.86%, 0.99% and 5.17% under current experimental condition, respectively. This work demonstrated that microchip laser-based SD-LIBS combined with OPC method can be used to realize convenient quantitative elemental analysis of zinc contained alloy samples with reliable accuracy.
10.1016-j.ijleo.2023.170839	17	wear; composites; coating; friction; composite; coatings; surface; tribological; properties; wear resistance; resistance; powder; sliding; matrix; wear rate	Cu-Sn-Ti has the advantages of excellent properties and low cost, which makes it suitable to be used as a bonding agent for CBN grinding wheels. In this paper, laser cladding was used to obtain Cu-Sn-Ti clad layers on the surface of 316 L steel substrate, and the effects of process parameters (laser power, scanning speed and powder feeding rate) on the clad height, melting pool width, melting pool depth and dilution rate were investigated. Then, the extent of the effect of different process parameters on the clad layer morphology and the reasons for it were analyzed in terms of laser energy as well as absorbed energy. Finally, the numerical prediction models of the morphological characteristic parameters of the clad layer were established and the microhardness of the clad layer was measured. The results showed that the coefficients of determination of the numerical prediction models for clad height, melting pool width, and melting pool depth were 0.9723, 0.9688, and 0.9840, respectively. The maximum relative error of dilution rate was 3.6%. The microhardness of the clad layer reached 310.6-366.2 HV0.5. The results provided theoretical support for the deposition of Cu-Sn-Ti bonding layers with outstanding morphology on the surface of 316 L substrates.
10.1016-j.ijmachtools.2020.103686	-1		Vaporization of alloying elements is an important phenomenon during laser powder bed fusion (LPBF), especially in the laser interaction with difficult-to-form materials containing the volatile element as main alloying element, which has a significant effect on the chemical composition, microstructure and mechanical properties. However, the mechanisms of the typical phenomenon in vaporization, such as the explosion, and its influence on the forming quality are not fully understood. Here, based on the in situ high-speed high-resolution imaging, we observe the explosion of the molten pool with temporal scale of similar to 10(1) mu s and spatial scale of similar to 10(1)-10(2) mu m during LPBF of Cu-10Zn. This micro-explosion can be attributed to the drastic augment of the saturated vapor pressure of Zn component in the molten pool. Theoretical calculations of vaporization amount in the explosion process by Miedema's model and Langmuir' s equation, are agreed well with the experimental results of volume increment for vaporization-induced inflation of the droplet spattering. Moreover, we also reveal a new defect formation mechanism, explosion-induced crater, which is detrimental to the forming quality in LPBF. The explosion-induced crater defect can be mitigated by increasing the lifetime of the molten pool, thus improve the continuity and flatness of the melt track. This study is expected to provide the scientific basis for LPBF of difficult-to-form materials to achieve stable forming with fewer defects.
10.1016-j.ijmecsci.2009.09.004	-1		Beryllium-copper alloys present a combination of high tensile and compressive strength, high hardness, good thermal conductivity and high resistance to seizing and galling (conditions where metals begin to cold weld or bond under the joint influence of compressive stress and relative motion at temperatures far below the melting temperature). These properties make beryllium-copper an excellent choice for bearing and bushing applications. Objective of this paper is to report the results of experimental tests carried out in order to evaluate the friction behaviour of threaded joints with at least one element made of Cu-Be; the other element is made of Cu-Be, steel or aluminium. The analysis of the results enabled us to establish that a threaded connection where an element is made of Cu-Be and the other one of steel, dry or at most lubricated by mineral oil, shows very encouraging frictional properties and can be considered as a good substitute for the usual joints made of steel and lubricated with environmental dangerous compounds.
10.1016-j.ijmecsci.2021.106957	-1		The ultra-high transience and complexity of the LPBF process brings critical challenges to understanding the underlying physics behind the defect formation, and mathematical modeling of the melt pool dynamics in LPBF is being a good method to overcome this issue. Since the laser heating is central to the LPBF process, it is vital to pay more attention to how to define the laser heat source in simulation. This study focuses on the top free surface heat source model that is widely used in existing literatures, of which two aspects of deficiencies are modified. On the one hand, the loading pattern of heat source at the interface is optimized by a proposed scattered heat source (SHS) model. The results show that the SHS model has an apparent advantage of less generation of artificial high temperature and better energy convergence. On the other hand, a calorimetric measurement is adopted to obtain the practical effective laser absorptivity under different process parameters. With implantation of measured absorptivity, the simulation fidelity compared to experiments is significantly enhanced in terms the track width and depth, and the absorptivity uncertainty derived from existing literatures on modeling copper alloy is well solved. Next, the physics behind the variation of effective absorptivity with scan speed is studied. Then, the characteristics of Cu-Cr-Zr alloy in LPBF induced by the huge thermal conductivity is identified by comparing with the case of commonly LPBF-used material (stainless steel 316 L). Finally, the influence of scan speed on the resultant track morphology and keyhole-induced porosity evolution is discussed.
10.1016-j.ijmecsci.2025.110741	14	strength; properties; conductivity; electrical; mechanical; cu-; grain; mpa; electrical conductivity; aging; precipitation; phase; mechanical properties; tensile; phases	This study presents a novel processing strategy that enables unprecedented bendability in a high-strength Cu-Ni-Si alloy containing 4.5 wt% Ni-achieving a bend radius-to-thickness ratio of 0.25 without cracking, which significantly exceeds previously reported performance. The key approach lies in particle-assisted texture engineering, achieved through intermediate annealing (IA). Texture analysis reveals that IA promotes the formation of cube ({001}<100>) texture within particle-affected deformation zones (PADZs) surrounding dispersed Ni2Si particles, thereby triggering localized recrystallization. The cube texture fraction increases markedly to 14 % in the IA-treated alloy, compared to only 2 % in the untreated counterpart. Despite comparable mechanical and electrical properties between the two alloys, the IA-treated alloy exhibits markedly superior bendability. This improvement is attributed to the suppression of shear banding, enabled by the increased cube texture. Crystal plasticity finite element modeling elucidates the mechanistic link between PADZs and texture evolution, offering quantitative insight into the microstructural origins of bendability. These findings demonstrate that IA and particle dispersion are effective strategies for tailoring crystallographic textures to achieve exceptional bendability in high-strength Cu alloys. This work offers a pathway for designing high-performance Cu alloys suitable for next-generation electronic components.
10.1016-j.ijnonlinmec.2004.05.005	-1		In this paper we develop a free energy function for a Cu-AI-Ni alloy undergoing cubic-orthorhombic phase transitions. We use the irreducible Lagrangian strain polynomial invariants of the cubic austenite parent phase to construct a polynomial expansion for the Helmholtz free energy. Our expansion retains quartic terms of the strain components in order to describe the two-phase material-the cubic austenite phase and six variants of the orthorhombic martensite phase. The coefficients of the free energy polynomial function are temperature dependent and are fitted to appropriate experimental data for austenite and martensite phases from literature. The resulting Helmholtz free energy function is given by (3.20), (4. 11). We examine the response predicted by the model for shear in the twinning directions.
10.1016-j.ijoes.2023.100315	2	corrosion; surface; film; electrochemical; films; spectroscopy; layer; current; solution; potential; resistance; composition; x-ray; ions; showed	In this work, a Cu-Zn bimetallic electrode was prepared using a facile electrodeposition technique. Structural and morphological analyses of the electrode samples showed that the explored range has a linear relationship with the composition, consistent with the formation of Cu and Zn in the electrode. The scanning electron microscope images of the fabricated Cu-Zn bimetallic electrode exhibited a cauliflower-like morphology with voids. Cyclic voltammetry studies indicated a clear pseudocapacitive nature of the electrodeposited Cu-Zn electrode material. The Cu-Zn redox electrode deposited for 30 min exhibited the highest specific capacitance of 699 F g-1 at a scan rate of 10 mV s-1. Moreover, the fabricated Cu-Zn electrode demonstrated an excellent capacitance retention of 84 % for 5000 consecutive charge-discharge cycles. The structural stability was also well maintained with an agglomerated spherical morphology filled with several nanorod-type structures. The results elucidate on the mechanisms for electrodeposition and effect of process parameters, such as applied voltage and deposition duration, on enhancing the electrode morphology and electrochemical behavior of Cu-Zn bimetallic electrodes. Our work provides an effective strategy for fabricating high-performance supercapacitor electrodes through a facile method.
10.1016-j.ijoes.2023.100378	-1		In present work, the immersion and electrochemical corrosion resistance of single-crystal copper with (100), (110), (111) preferred orientation were studied in 3.5 NaCl solution. The scanning electron microscopy and X-ray photoelectron spectroscopy, Laser Raman spectroscopy were used to observe corroded surface morphology and analyze the corroded products. The experimental results show that preferential orientation has a significant effect on the corrosion resistance of single crystal copper. The self-corrosion current densities of (100), (110), and (111) oriented single-crystal copper were 1.1455 mu A/cm(2),0.7312 mu A/cm(2) and 1.4117 mu A/cm(2) respectively. The corrosion resistance was in the order of (110) > (100) >(111). Optimally oriented surface can effectively improve the corrosion resistance of copper.
10.1016-j.ijoes.2023.100429	2	corrosion; surface; film; electrochemical; films; spectroscopy; layer; current; solution; potential; resistance; composition; x-ray; ions; showed	The use of corrosion inhibitors is considered as the supreme dominant approach to control the damage of metallic corrosion. Organic dyes are extensively employed as inhibitors for the corrosion of various metals and alloys in diverse media. Herewith, Alcian blue dye (ABD) was selected to investigate its inhibitive characteristics against the corrosion of copper in 1.0 M H2SO4 solution at 298 K. This investigation was monitored by various chemical, electrochemical, and spectroscopic techniques. The results indicated that the examined dye is a pro-ficient inhibitor for the corrosion of copper in 1.0 M H2SO4 solution and its inhibition efficiency (% IE) was increased with augmenting its concentration and diminished with rising medium temperature. The high anti-corrosive ability of the selected dye was attributed to its adherent adsorption of such dye on the Cu surface and follows Langmuir isotherm. Thermodynamics and kinetics of corrosion of copper and its inhibition by the examined dye were inspected. The mechanisms of copper corrosion in H2SO4 solution and its inhibition by ABD were proposed. The obtained results illuminated that the examined dye acts as a mixed-type inhibitor with cathodic precedence. Finally, all gained results with respect to % IE values of the dye were compared and designated a good harmony between all applied techniques.
10.1016-j.ijplas.2006.04.004	-1		Motivated by recent unusual experimental results [Sittner, P., Hashimoto, K., Kato, M., Tokuda, M., 2003. Stress induced martensitic transformations in tension/torsion of CuAlNi single crystal tube. Scripta Materialia 48, 1153-1159] indicating a strong coupling between axial and torsional deformations in single crystal monoclinic-II shape memory alloy tubes, various computational aspects of numerically modelling the observed behavior in monoclinic-II materials are discussed. As a necessary first step, the shape strain computations in monoclinic-II systems are examined. It is found that ambiguities regarding the lattice parameters and proper unit cell in the existing literature have implications for the macroscopic constitutive theories of such alloys. This is demonstrated in the context of a detailed numerical investigation of the experimental problem of interest, wherein it is found that numerical simulations demonstrate proper quantitative response, a strong axial -> torsional coupling given a biasing initial condition, and the observed lack of torsional -> axial coupling. Implications of the findings are discussed with regard to both the further development of numerical models and future avenues for experimental research .
10.1016-j.ijplas.2007.07.007	4	transformation; martensite; martensitic; phase; shape; beta; memory; shape memory; temperature; temperatures; martensitic transformation; gamma; transformation temperatures; effect; thermal	The mechanical behavior of a solid capable of undergoing internal phase change is considered. Reversible and dissipative constitutive equations are established within the framework of generalized standard materials with internal constraints. These constraints are accounted for using Lagrange multipliers. The presented model is based upon a phenomenological configuration in series (Reuss model). In the case of reversible phase change, it is shown that the elastic energy of the material can be obtained by convexifying the energy functions of existing phases. In the dissipative case, it is shown how the behavior of the material can be made stable by developing evolution equations deriving from an adequately chosen dissipation potential. As an application, we propose a description of the thermomechanical behavior of shape memory alloys (SMAs). The obtained constitutive equations can be used to simulate the pseudoelastic response of SMAs as well as the one-way shape memory effect. Validation against experimental data is performed in the case of multi-axial complex thermomechanical loading for NiTi as well as Cu-based alloys.
10.1016-j.ijplas.2008.10.003	-1		Crystal lattice rotations induced by twinning and shear banding developed in a Cu-8 at% Al alloy (representative of fcc metals with low stacking fault energy) have been examined in order to investigate the influence of bands on slip propagation across a structure of twin-matrix layers and the resulting texture evolution. The microstructure and texture of (112)[11 (1) over bar] oriented single crystal plane strain compressed up to similar to 80% 77 K were characterized by transmission electron microscopy (TEM) including TEM orientation mapping. It is shown, that the strong, initial texture changes are due to deformation twinning. Two families of deformation twins, symmetric with respect to the plane perpendicular to the extension direction, are observed. However, only one of them plays a dominant role in strain accommodation. At larger deformations, twin-matrix deflection within some narrow areas leads to kink-type bands, and this is crucial for understanding further texture transformations. The kink bands are precursors of shear bands (SB). It is shown by detailed TEM orientation mapping how the structure of twins and matrix is incorporated into a SB, and what kind of the dislocation mechanisms are responsible for strain accommodation at the macro-scale. It was found that the re-orientation of the main (111) twinning planes towards the SB plane facilitates further dislocation slip in the shear direction. Finally, a crystallographic description of SB formation in completely twinned fcc metals is proposed based on lattice re-orientations due to localized kinking.
10.1016-j.ijplas.2010.05.007	-1		In this work, a silver-copper (Ag-Cu) nanocomposite with 200 nm bilayer thickness and eutectic composition was rolled at room temperature and 200 degrees C to nominal reductions of 75% and higher. Initially the material had a random texture and {1 1 1} bi-metal interface plane. X-ray diffraction measurements show that the Ag and Cu phases developed the same brass-type (or 'alloy-type') rolling texture regardless of rolling reduction and temperature. Transmission electron microscopy analyses of the nanostructures before and after rolling suggest that adjoining Ag and Cu layers maintained a cube-on-cube relationship but the interface plane changed after rolling. Polycrystal plasticity simulations accounting for plastic slip and deformation twinning in each phase were carried out to explore many possible causes for the brass-type texture development: twinning via a volume effect or barrier effect, Shockley partial slip, and confined layer slip. The results suggest that the observed texture evolution may be due to profuse twinning within both phases. Maintaining the cube-on-cube relationship would then imply that neighboring Ag and Cu crystals twinned by the same variant and on a twin plane non-parallel to the original interface plane. Explanations for this unusual possibility for Cu are provided at the end based on the properties of the Ag-Cu interface.
10.1016-j.ijplas.2020.102834	-1		The mobility of edge dislocation in Cu-Ni solid solution alloys within a wide range of temperatures 100-1100 K and Ni concentrations 0-30 at% is studied by molecular dynamics simulation. Two different regimes of the influence of substitutional Ni atoms on the motion of edge dislocation are observed. In the first regime, in which the velocity of edge dislocation is much less than the shear sound speed, Ni atoms act as barriers and slow the dislocation down. In this regime, the dependence of the edge dislocation velocity on Ni concentration weakens with increasing temperature. In the second regime, in which the dislocation moves faster, with a speed closer to the shear sound speed, Ni atoms accelerate its motion. The latter result is a consequence of higher shear sound speed along the [110] direction of Cu-Ni solid solution alloy associated with higher Ni content. The distance between Shockley partial dislocations representing the core of edge dislocation is analyzed as a function of temperature and Ni concentration. The partial splitting increases with temperature and decreases with Ni concentration. The latter result might be important for predicting strain hardening mechanisms in Cu-Ni alloys.
10.1016-j.ijplas.2021.102926	-1		A comprehensive understanding of the deformation behavior and strengthening mechanism of the selective laser melted (SLM) alloy is critical in reaping the complete potential of the SLM process. Accordingly, this work focuses on the influence of SLM on the microstructure, deformation behavior, and mechanical properties of the Cu-Ni-Sn alloy compared with their cast (CC) counterparts. An equiaxed-columnar bimodal structure with dispersed gamma particles was observed due to the rapid solidification conditions, which helps in eliminating the otherwise formed brittle dendrite structure. The unique SLM microstructure with increased dislocation density offers a superior combination of tensile strength and ductility that is much higher than the CC samples. The SLM microstructure involving dislocation cells and fine precipitations led to a relatively high strain rate sensitivity (0.012 +/- 0.002) and a small activation volume (similar to 115 b(3)). It has been observed that in the as-prepared SLM material the strength contribution comes mainly from grain refinement, dispersed precipitation, and increased dislocation density.
10.1016-j.ijplas.2022.103340	6	grain; deformation; strain; strength; dislocation; cu-; tensile; size; ecap; grain size; sfe; ductility; hardening; high; stress	The present study addresses the evolution of microstructural and crystallographic texture in room-temperature-rolled (RTR) and cryogenic-rolled (CR) electrolytic tough-pitch (ETP) copper. Copper specimens were subjected to 20, 40, 60, and 80% reductions via RTR and CR processing. The microstructure evolution of the severely deformed RTR and CR specimens revealed deformed and recrystallized grains. Static recrystallization (SRX) at room temperature (RT) was observed in the severely deformed RTR and CR specimens. Both discontinuous SRX (DSRX) and continuous SRX (CSRX) were responsible for the nucleation of small grains at RT. Particle-stimulated nucleation (PSN) was also responsible for small-grain formations around the Cu2O particles. The initial ETP copper specimen showed a weak texture whose intensity increased after the RTR and CR deformation. The texture intensity of the severely deformed specimens was affected by both deformation and the SRX phenomena. The CR specimens showed texture that was stronger than that of the RTR specimens up to the point of an intermediate reduction (60%), whereas at higher deformation (80%), the RTR specimens showed stronger texture intensity compared with that of the CR specimens. The texture weakening in the CR80 specimen was due to the formation of strain localizations (SLs) and to the nucleation at SLs. Large amounts of stored energy and SL formation in severely deformed CR specimens led to a different recrystallization texture compared with that of RTR specimens. A Cube component was dominant in the RTR80, whereas Goss, Copper and S components were observed in the CR80 specimen for SRX grains. The CR specimen showed a relatively high hardness value compared with the RTR specimen. Time-dependent decay in the hardness values for both the RTR and the CR specimens were attributed to roomtemperature recovery (SRV) and recrystallization (SRX).
10.1016-j.ijplas.2022.103473	6	grain; deformation; strain; strength; dislocation; cu-; tensile; size; ecap; grain size; sfe; ductility; hardening; high; stress	The present study addresses the microstructural and texture evolution of Cu-Fe-P alloy sheets rolled at room temperature (RT). Cu-Fe-P specimens were subjected to 20, 40, 60, and 80% reduction ratios (RR) through room-temperature rolling (RTR). Nano-sized Fe2P precipitates were observed in the initial and deformed specimens. Continuous-rolling deformation causes strain hardening, whereas exposing severely deformed specimens to RT causes the self-annealing phenomenon. Deformed specimens to 60 and 80% RRs exhibited strain localizations (SLs) that formed only in Copper-type grains. In this study, a visco-plastic self-consistent (VPSC) polycrystal model was used to calculate the relative slip activity for major texture orientations. Copper-type grains showed the occurrence of predominant single-slip system which was the primary reason for the formation of SLs. Static recovery (SRV) and static recrystallization (SRX) were the main softening phenomena found in the RTR specimens. Both discontinuous SRX (DSRX) and continuous SRX (CSRX) were observed as the SRX phenomenon in RTR specimens. Major SRX grains were elongated in shape due to the combined effects of a higher orientation gradient (CSRX), to the larger SE differences between the matrix grains (restricted growth), and to a pinning effect by Fe2P particles. The as-received specimen showed weak plane-strain texture components at maxima around the S component ((123)< 634 >). As the RR increased, the volume fractions of Copper ((112)< 111 >), Brass ((110)< 112 >), and S components were likewise increased (except at 60% RR). The highest fraction of plane-strain components was observed for the RTR-80 specimen. The large number of SLs and the higher orientation gradient decreased the intensity of the plane-strain texture in the RTR-60 specimen, whereas a higher fraction of SRX in the RTR80 specimen enhanced the plane-strain texture components. Time-dependent decay in the hardness values in the RTR specimens were attributed to SRV and SRX.
10.1016-j.ijplas.2023.103672	6	grain; deformation; strain; strength; dislocation; cu-; tensile; size; ecap; grain size; sfe; ductility; hardening; high; stress	Deformation of Cu-Fe-P alloys at cryogenic temperature (CT) leads to the evolution of a complex microstructure, which includes deformed and recrystallized grains, strain localizations (SLs), and heterogeneous deformation. In this study, specimens of Cu-Fe-P alloy were subjected to cryogenic rolling (CR) at reduction ratios (RR) of 20, 40, 60, and 80%. The microstructural evolution of the CR specimens was characterized using electron back-scattered diffraction (EBSD) and highresolution transmission electron microscopy (HR-TEM). Severely deformed CR specimens showed SLs, which formed predominantly in the Copper and S oriented grains. After deformation, the CR specimens exhibited self-annealing behavior, which is also referred to as static recrystallization (SRX). Self-annealing at room temperature (RT) caused grain nucleation at the deformed grain boundaries (GBs) and at the SLs. The nucleation of new grains was attributed to both discontinuous SRX (DSRX) and continuous SRX (CSRX) phenomena. The characteristics of DSRX and CSRX grains were analyzed based on transmission Kikuchi diffraction (TKD) and HRTEM investigations. DSRX grains were surrounded by high-angle GBs, whereas CSRX grains showed sub-boundaries with no dislocations inside. The as-received Cu-Fe-P specimen showed a weak plane-strain texture that intensity increased with an increase in the RR. The CR-80 specimen showed the highest-intensity for plane-strain texture components. SRX at the SLs showed preferential formations of Copper, Brass and S-nucleated grains in the CR-80 specimen. In this study, crystal plasticity finite element method (CPFEM) was used to calculate the stored energy, relative slip activity and texture fractions for the CR specimens. Copper and S oriented grains showed the occurrence of predominant single-slip systems near the severely deformed regions which was the primary cause of SLs formation.
10.1016-j.ijplas.2024.104181	14	strength; properties; conductivity; electrical; mechanical; cu-; grain; mpa; electrical conductivity; aging; precipitation; phase; mechanical properties; tensile; phases	Void characteristics are fundamentally correlated with the macroscopic deformation responses of materials, yet traditional modeling methods exhibit inherent limitations in data mining. In this study, a machine learning (ML) framework is proposed to predict the full-field strain evolution of Cu/Ni clad foils, and the impact of intrinsic voids is quantitatively assessed using interpretative analysis methods. The local strain and void data are extracted and integrated through digital image correlation and computed tomography. To accommodate the nature of the constructed dataset, a ML model is established with reference to the concept of time series forecasting. Subsequently, the influence of microstructural features such as volume fraction (VVF), area, and size of voids are investigated, alongside their role in driving local strain evolution. This approach successfully predicts strain localization, and accurately pinpoints the onset of plastic instability and the location of crack initiation. The VVF is identified as the most predominant factor, followed by void size along the tensile direction and grain size. The strongest association is observed between the VVF and grain size, which intensifies over extended time scales. Moreover, as void coalescence is almost completed, the promoting effect of the concentrated void distribution on macroscopic strain concentration will become increasingly pronounced. These findings provide novel perspectives for exploring the intricate relationship between deformation and damage.
10.1016-j.ijplas.2024.104188	14	strength; properties; conductivity; electrical; mechanical; cu-; grain; mpa; electrical conductivity; aging; precipitation; phase; mechanical properties; tensile; phases	W-Cu bimetallic composites are commonly employed in a wide range of critical fields due to their exceptional comprehensive performance. However, the weak interfacial bonding between two distinctive phases results in challenges such as easy deformation, poor mechanical performance, and short lifespan. In present work, by adopting thermo-mechanical processing (TMP) treatment, the W and Cu phases, connected by the nano-diffusion layer, underwent a cooperative deformation process. Meanwhile, the pre-existing nanoclusters anchored the accumulated dislocations during TMP, forming a unique continuous cellular dislocation structure (CC-D) with the nanoscale size of approximately 40 nm during the subsequent recovery annealing process. The CC-D dominated plastic deformation mechanism dynamically refined the grains by forming a multiscale network of stacking faults and deformation twins (SFs-DTs). Moreover, the slip transfer and twinning originating from the W/Cu interface were stimulated to alleviate interfacial stress accumulation. Thus, the ensuing strengthening and strain-hardening mechanisms maintained stable tensile flow, resulting in an exceptional strength-ductility combination (965 MPa, 14.8 %). Moreover, the high density of twins within the Cu grains, with numerous coherent twin boundaries, reduced electron scattering and maintained a considerable electrical conductivity (30 % IACS) for the bimetallic composites.
10.1016-j.ijplas.2025.104460	-1		The W-Cu composite, a representative of immiscible metal matrix composites (MMCs), plays a crucial role in fields requiring both mechanical and physical properties. However, the weak interfacial bonding capability between the immiscible phases lead to poor mechanical response. In present work, a considerable interpenetrating diffusion layer and an atomic bonding interface (termed as the 3D interface) with a considerable thickness of similar to 10 nm was constructed through the introduction of negative mixing enthalpy elements. Additionally, a partially recrystallized (PRX) heterogeneous matrix was built through precise thermomechanical processing (TMP) treatment. The presence of the 3D interface and PRX structure created additional space for dislocation storage, leading to a high level of heterogeneous deformation-induced (HDI) stress. On one hand, intensified activation stress was triggered for twinning in the face-centered cubic (FCC) matrix, promoting twin-mediated dynamic recrystallization (TDRX) during tensile deformation and effectively alleviating stress concentration. On the other hand, the resulting long-range internal stress not only induced large-scale abnormal twinning and phase transformation at the interface, enhancing work-hardening capacity, but also significantly improved load transfer across the W/Cu interface. In addition, the abundant sub-grain structures and free dislocations induced by rolling deformation promote the plasticization of W particles. Consequently, the composite subjected solely to straightforward infiltration and TMP (including hot rolling, warm rolling, and cold rolling) achieved a remarkable enhancement in both strength and ductility, with the cold-rolled sample exhibiting an ultrahigh tensile strength-ductility combination (1290 MPa, 8.5 %), representing a 2-3 times enhancement over conventional W-Cu composites. This work elucidates nanoscale interface-dislocation interactions in MMCs, shedding new light on the development of structure-function-integrated materials.
10.1016-j.ijpvp.2021.104433	-1		Offshore seawater systems are commonly manufactured using a monolithic copper-nickel alloy (90%Cu10%Ni). However, because of the high cost of this material, they have been replaced in some Brazilian oil and gas platforms by C-Mn steel pipes clad with a Ni-Cu alloy (70%Ni30%Cu, Monel 400 (R)). Therefore, considering the complex transition zone (TZ) in dissimilar weldments and its influence on the performance of the clad component, the present work aims to characterize the TZ of an API 5L X65 steel pipe clad with a 70%Ni30%Cu alloy by hot-wire gas tungsten arc welding (HW-GTAW). The TZ was evaluated using optical microscopy, scanning electron microscopy, electron backscatter diffraction, Vickers microhardness measurements, and bending tests. It exhibited beach, peninsula, and island macrosegregation morphologies with martensite (high hardness) and type II grain boundaries as well as an abrupt chemical composition gradient and Zone M. Moreover, the cladding solidified epitaxially, even though the cladding and the substrate had different crystal lattices. A solidification grain boundary crack, observed in the pipe end, nucleated in the substrate and propagated through the beach macrosegregation and posteriorly along the cladding grain boundaries. Despite this crack, the API 5L X65 steel pipe clad with 70%Ni30%Cu was approved according to ISO 15614 Part 7 and is a potential candidate for seawater systems.
10.1016-j.ijrefrig.2020.02.020	1	shape; memory; shape memory; damping; martensite; martensitic; damping capacity; transformation; capacity; strain; superelasticity; temperature; cu-al-mn; shape memory effect; effect	The cyclic stability of the elastocaloric effect (eCE) is an important performance for elastocaloric refrigeration. Our previously work showed that Cu-Al-Mn microwires with bamboo grains exhibited favorable eCE with small hysteresis. Here, we demonstrated that oligocrystalline grain architecture in Cu-Al-Mn microwires created via multi-step cold-drawing having favorable eCE cyclic stability. The oligocrystalline grains exhibited a preferential < 101 > orientation along the wire axis. The annealed microwire with diameter 130 mu m showed stress-induced entropy change (Delta S-sigma) of 5.0 J kg(-1) K-1 but degraded rapidly after similar to 15 cycles. On the other hand, the as-drawn microwire with diameter 130 mu m showed a large entropy change (Delta S-sigma) of 10.3 J kg(-1) K-1 and a temperature change (Delta T) of 4.5 K with fast fatigue rate. Moreover, the microwire exhibited a smaller Delta T = 3.0 K with stability up to 275 cycles for further cold-drawn to diameter 80 mu m. The enhanced cyclic stability of elastocaloric effect in as-drawn microwire was attributed the favorable grain orientation and enhanced yield strength induced by cold-drawing. This work is instructive for designing high-performance Cu-based elastocaloric materials for solid-state cooling applications.
10.1016-j.ijrmhm.2008.10.018	16	wear; composite; composites; powders; milling; particles; powder; wt; sliding; friction; hardness; matrix; mechanical; surface; properties	The aim of this preliminary investigation is to study the performance of three distinct cutting tools, cemented carbide (WC), chemical vapour deposition diamond (CVDD) and polycrystalline diamond (PCD) when dry machining a copper-tungsten alloy. Cutting and feed forces, maximum cutting temperature, surface roughness and tool wear will be studied in function of the cutting time and each cutting tool. It can be stated that, for the applied cutting conditions, the tool that proved to have the best performance from a wear point of view, is the WC cutting tool. From a surface roughness point of view, the CVDD cutting tool is very similar to WC, leaving the PCD cutting tool with a lower performance.
10.1016-j.ijrmhm.2010.10.012	-1		In order to clarify the effect of Fe addition on vacuum arc characteristics of CuCr alloys, the CuCr50, CuCr45Fe5 and CuCr40Fe10 alloys were prepared by vacuum sintering and infiltrating, and the simulated electrical breakdown experiment was undertaken in a vacuum interrupter. The characteristics of the motion of vacuum arcs were analyzed by a digital high-speed video camera and the erosion morphology was characterized by a scanning electron microscope (SEM). The results show that Fe additions can strengthen the Cr phase, promote the first breakdown phase to transfer from Cr to Cu and increase the strength of the alloy breakdown voltage by 80%. Meanwhile, Fe additions can still retain the arc stability of CuCr50 alloys during the generation and extinguishing process, decrease the chopping current, and prolong the arc life. Furthermore, the characteristics of the split and motion of cathode spots on the surface of the CuCr40Fe10 alloy were improved, which prohibits the concentrated arc erosion.
10.1016-j.ijrmhm.2011.04.014	-1		CuW alloys with different Fe additions were prepared by the infiltration method. The microstructures of the CuW alloys prepared were characterized by a transmission electron microscope (TEM). The effect of Fe content on the surface erosion morphology was observed by a scanning electron microscope (SEM). The distribution of cathode spots was analyzed by a digital high-speed video camera. The results show that Fe addition can improve the relative density and thermal conductivity of CuW alloy with less than 0.6 wt% Fe. However, excessive Fe addition can deteriorate the relative density and thermal conductivity. TEM results show that Fe addition can promote the formation of CuW solution. The area and depth of the erosion pits on the surface of CuW alloy depend on the breakdown position. Fe addition can strengthen the interface bond of Cu and W, improve the arc stability and the division of the cathode spots and, thus, avoid the concentration erosion.
10.1016-j.ijrmhm.2011.07.017	16	wear; composite; composites; powders; milling; particles; powder; wt; sliding; friction; hardness; matrix; mechanical; surface; properties	The properties of W-15 wt%Cu composites were investigated by preparing two distinct composites of micrometer and nanoscale structures. Micrometer composite was produced by mixing elemental W and Cu powders and nanometer one was synthesized through a mechanochemical reaction between WO(3) and CuO powders. Subsequent compaction and sintering process was performed to ensure maximum possible densification at 1000-1200 degrees C temperatures. Finally, the behavior of produced samples including relative density, hardness, compressive strength, electrical conductivity, coefficient of thermal expansion (CTE) and room temperature corrosion resistance were examined. Among the composites, nano-structured sample sintered at 1200 degrees C exhibited better homogeneity, the highest relative density (94%) and mechanical properties. Furthermore, this composite showed superior electrical conductivity (31.58 IACS) and CTE (9.95384x10(-6)) in comparison with micrometer type. This appropriate properties may be mainly attributed to liquid phase sintering with particle rearrangement which induced by higher capillary forces of finer structures.
10.1016-j.ijrmhm.2013.12.004	-1		Full-density of consolidated W-Cu composites produced via conventional sintering method is difficult to achieve. In this work, fully-dense W-Cu composites were developed via the combination of the liquid phase sintering (LPS) and the liquid infiltration (LI) methods, which hereinafter is named as Cu-MI technique. It operates at the low sintering temperature of 1150 degrees C, and maximum densification was possible without requiring a sintering activator such as Ni, Co or Fe. A comparison was also made between the sintering response of W-(13-27 wt%) Cu composites consolidated using LPS and Cu-MI techniques. The samples were characterized using SEM, EDX and XRD. It was observed that the samples prepared via the Cu-MI method demonstrated a high relative density (>99% theoretical density). Contrary to the composite sample prepared by the LPS method, the Cu-MI technique accounted for a homogeneous microstructure almost without any pores. The significance of this finding has major industrial implications and has potential to reduce the production costs of composite materials with improved mechanical and electrical properties.
10.1016-j.ijrmhm.2015.04.009	16	wear; composite; composites; powders; milling; particles; powder; wt; sliding; friction; hardness; matrix; mechanical; surface; properties	This work reports the influence of the use of composite particles of composition Nb-20 wt%Cu and the compaction pressure on density and structure of sintered pieces. High energy milling is used to produce the composite powders. Milling times of 2, 20,50 and 100 h were used. The powders were pressed under 200, 300, 400 and 500 MPa and sintered at 1100 degrees C for 60 min. After sintering, density was measured and cross sections of the structures were observed under SEM. The electric conductivity was also measured. Density and electric conductivity behave similarly with respect to compaction pressure and milling time. Cracks are created during pressing and ejection of the green pieces from the die. The cracks are mainly present in samples prepared with powders milled longer and are not closed by sintering. On the other hand, sintering can close most of the pores formed by the composite particles.
10.1016-j.ijrmhm.2016.05.014	-1		In the present work, several W-25 wt% Cu alloys have been prepared through combined processes of high-energy ball-milling, liquid-phase sintering and infiltration, using the precursors of industrial copper powders with an average particle size of 50 mu m and tungsten powders with alternative average particle size of 8 pun, 800 nm, 600 nm or 400 nm. Microstructure characteristics, relative density, hardness and electrical conductivity of the WCu alloys were investigated to elucidate the effect of initial particle size of tungsten powders. EBSD was further utilized to reveal the orientation and grain size distribution in the WCu alloys prepared by 8 jam and 400 nm-sized tungsten powders. The results showed that the WCu alloy made by 400 nm-sized tungsten powders exhibited excellent homogeneity for both sintered tungsten powders and grains, together with the highest relative density of 98.9%, the highest hardness of 230 HB, and good electrical conductivity of 48.7% IACS. Moreover, it also showed highly improved arc erosion and mechanical wear resistances. (C) 2016 Published by Elsevier Ltd.
10.1016-j.ijrmhm.2016.11.005	17	wear; composites; coating; friction; composite; coatings; surface; tribological; properties; wear resistance; resistance; powder; sliding; matrix; wear rate	Filler alloy can strongly influence the performance of brazed monolayer diamond grinding tools. Cu-Sn-Ti and modified Cu-based filler alloy added with Ni-Cr-B-Si were used to braze diamond. The morphology of the diamond and the microstructure of the filler alloy were analyzed by SEM, EDS, and XRD. The hardness of the alloy was also determined with a microhardness tester. The results show that filler alloy containing Cu, Sn metal powder, and 16%Ni-Cr-B-Si is suitable for brazing diamond. The morphology of the brazed diamond is intact, and the filler alloy catalyzes the chemical metallurgical bonding with the diamond. Different kinds of carbide are formed on different crystal faces of the diamond. Cu-based dendrites, Cu5.6Sn, Cu3Sn, and Ni(3)sn are formed on the filler alloy during solidification. The hardness of the modified Cu-based filler alloy increases with increasing proportion of Ni-Cr-B-Si added. In particular, the hardness of the modified Cu-based filler alloy containing 16 wt% Ni-Cr-B-Si reaches 340-360 HV0.3, which is three times the hardness of the Cu-Sn-Ti filler metal.
10.1016-j.ijrmhm.2017.11.020	-1		In this work, novel high-voltage electrical contacts of the W-Cu composites reinforced with tungsten fibers (W-f) have been fabricated by hot-press sintering and infiltration processes. Considering microstructural homogeneity and fabrication repeatability of the composites, Wf with the content of 3.3 wt% was determined to be optimum for the reinforcement. By electroless deposition of similar to 2.5 pm thick nickel layer onto the surface of W-f, the connectivity between the W-f and its neighboring W-Cu matrix after sintering and infiltration was improved with the elimination of porosity. This was considered to be ascribed to the plastic deformation of Ni-coatings during the molding of green compacts and the improvement of rearrangement of tungsten particles (W-p) during the Ni-activated sintering. Compared with the traditional commercial W-Cu composites, the W-Cu composite reinforced with the Ni-coated W-f provided desirable increased tensile strength by 15.8% and improved electrical breakdown strength by 65.3% after the interface tuning, which is applicable and transferrable to other refractory metals for property improvement.
10.1016-j.ijrmhm.2017.11.042	17	wear; composites; coating; friction; composite; coatings; surface; tribological; properties; wear resistance; resistance; powder; sliding; matrix; wear rate	W-20Cu composites were fabricated by electroless plating and low-temperature hot pressure sintering (850 degrees C) with different content of Ag particles range from 0 to 2.5 wt% as additives. The impacts of Ag additives on the densification and properties of W-Cu composites were investigated. X-ray diffraction and Field emission scanning electron microscope coupled with energy dispersive spectrum were used to analyze the phase and microstructure of powder and sintered composites. Relative density, electrical conductivity, Vickers hardness and bending strength were measured. W-20Cu composite powders prepared by electroless plating exhibited dense and uniform structure. The results showed that the addition of Ag had significant effect on the microstructure and properties of W-Cu composites, and the optimal content of Ag particles is 2 wt%. After added of 2 wt% Ag, the relative density of sintered W-Cu composites can achieved to 98.57%, the electrical conductivity reached 46.5% IACS, mechanical properties improved greatly due to the formation of solid solution during activated sintering, Vickers hardness and bending strength can reached 227.6 HV and 894.72 MPa, respectively.
10.1016-j.ijrmhm.2018.04.008	-1		Cu-refractory metal composites containing Cr, Mo or W were subjected to severe plastic deformation using room temperature high-pressure torsion (HPT). A lamellar microstructure developed in each of the composites at equivalent strains of similar to 75. The refractory metals developed {hkl}<111> fibre textures with a slight tilt to the tangential direction. This texture was stronger and more clearly defined in Mo and W than in Cr. By applying additional HPT deformation to these samples, perpendicular to the original shear strain, it was found that the lamellar structure of Cu30Mo70 and Cu20W80 (wt%) composites could be retained at high equivalent strains and the refractory layer thickness could be reduced to 20-50 nm in Cu20W80 and 10-20 nm in Cu30Mo70. Although neighbouring regions of the microstructure were aligned and there was evidence of local texture in both composites, the bulk texture of Cu30Mo70 became weaker during this second step of HPT deformation. This was attributed to the refractory metal lamellae being discontinuous and imperfectly aligned. This work shows that it is possible to form ultrafine composites of Cu-group VI refractory metals via high-pressure torsion, with namolamellar structures being possible where there is a sufficient volume fraction of Mo or W.
10.1016-j.ijrmhm.2019.02.015	-1		Tungsten-copper composites of network structure are increasingly being studied because of their unique mechanical, thermal and electrical properties. Chemical plating and mechanical alloying were used to prepare tungsten-copper alloys with different compositions in this investigation. Samples obtained through mechanical alloying method and sintered by spark plasma sintering (SPS) technique at 1030 degrees C, 60 MPa exhibited excellent performance. Ni element and Cr element were added to the composite as activating elements to improve the interface wettability of tungsten-copper. The experimental results showed the Cr element contributes more to the densities, tensile strength, flexural strength and thermal properties of the composites than Ni element. Besides, the effect of two different ball milling ways on the properties of the composites was also studied. The sample W-20Cu (15Cr), which was prepared by Cu(Cr) ball milling, showing a network structure, has the best performance.
10.1016-j.ijrmhm.2019.03.026	-1		In order to solve problems of significant interfacial reactions and agglomeration in graphene reinforced W-Cu composites, powders of copper coated graphene (Cu@Gr) were pre-mechanically mixed with tungsten and copper powders, and then graphene doped W-Cu composites were sintered using two different methods, e.g., spark plasma sintering (SPS) and infiltration sintering. Microstructural analysis showed that the doped Cu@Gr powder can effectively inhibit the interfacial reaction between graphene and tungsten, prevent the segregation of graphene, and evenly distribute the copper in the binder phase. When the mixed concentration of Cu@Gr was 0.45 wt%, uniform distributions of W phase and Cu phase were obtained in the composite, and the mechanical properties and conductivity of this composite achieved their best results. When the doping content was further increased to 0.8%, WC phase was found in all alloys, thus resulting in poor mechanical and physical properties. Comparing the microstructures produced using these two methods, the composites prepared using the infiltration sintering method showed network distribution of copper phase and segregation of copper, whereas the composites prepared using the SPS method showed network skeleton phase of tungsten. Although the SPS process was performed in a much shorter time, the mechanical properties of the composites sintered using the SPS process did not show much differences with those sintered using the infiltration sintering method.
10.1016-j.ijrmhm.2019.105144	-1		Metal bond diamond abrasive tools with complex structure and high wear efficiency will be widely used in the geological drilling and mechanical processing industries, but are difficult to manufacture by traditional technology. In this paper, selective laser melting (SLM), as one of the additive manufacturing technologies, was used to fabricate Cu-Sn-Ti bonded diamond abrasive composites. Simulations, experiments and characterization were carried out to obtain the appropriate SLM process parameters. Results indicated that the optimal SLM parameters were laser power of 260 W, scanning speed of 300 mm/s and layer thickness of 0.09 mm. Furthermore, the wear resistant performance of SLM sample was compared with hot-pressed sintered sample in terms of mass loss rate, wear morphology and bonding condition. Results showed that diamond particles were seriously pulled-out from hot-pressed sintered sample while this hardly occurred from the wear surface of SLM sample, which was benefited from higher amounts of TiC around the diamond. Consequently, the bonding force to diamond was effectively improved for SLM sample. Therefore, SLM method cannot only fabricated sample with complex structures, but also with better performance. This study provides a novel approach for forming metal bonded diamond tools by SLM in the future.
10.1016-j.ijrmhm.2019.105172	-1		In this paper, a type of soft metal binder of diamond tools (diamond segments) that was consisted of 78% Brass (Cu-10Zn) +16% Bronze (Cu-10Sn)+%6Co was investigated. The first, it was approved that the binder is a soft metal binder by a hardness test for diamond tools in natural stones cutting. Then, the effective factors on grinding efficiency such as specific energy (SE), Cutting force (FC), metal binder removal rate (MRR), grinding ratio (G-ratio), wear resistance and Mean free path (MFP) were evaluated by different formula and equations. On the other hand, the effect of different wear mechanisms on the metal binder and diamond grits of the tool was evaluated by the cutting of a type of very hard marble stone that calls Cappochino Beige Marble (CBM). The existence of wears of abrasive, surface fatigue, impact and erosive were confirmed by scanning electron microscopic observations. According to hardness 73 HRB (hardness of the binder) and the wears, there is a short tools life for the diamond tool due to low wear resistance of the metal binder but, the cutting rate was high . Novelty statement: The rising price of decorative stones will increase the final price of the stones and will overshadow the global market of decorative stones. The presence of cobalt, iron, chromium and nickel powders increases the price of diamond tools because of their high price. On the other hand, due to the higher temperature and time of hot press to produce these tools by the mentioned powders, it will also increase the price. Therefore, in this paper, brass and bronze alloy powders, which are much cheaper than cobalt, iron, chromium and nickel powders, have been used as main metal binder powders to reduce raw material prices and manufacturing process costs. On the other side, due to the creation of a softer metal binder compared with the more expensive and harder binder of cobalt, iron, chromium and nickel powders, it can be affected to increase the cutting speed because of increasing wear of the binder. Therefore, mathematical calculations are essential for the efficiency of the tools' cutting.
10.1016-j.ijrmhm.2020.105223	16	wear; composite; composites; powders; milling; particles; powder; wt; sliding; friction; hardness; matrix; mechanical; surface; properties	A mixture of Cu-20w%WC was milled in a high energy mill for up to 50 h . The WC powder was recycled from hard metal scrap. It presents agglomerates of faceted WC particles and residual Co and Fe. In the first hours of milling, the Cu particles are deformed into plates, the agglomerates of WC are broken apart, the primary WC particles are fragmented and embedded in the Cu phase. Composite particles are formed. As milling proceeds, different plates are welded together and folded. The particle size increases. However, the hardened Cu becomes fragile and begin to break, decreasing the particle size. Both, Cu and WC are under compressive strain. Residual Co and Fe present in the recycled powder are dissolved in Cu and behave like the soft Cu phase.
10.1016-j.ijrmhm.2020.105433	-1		The development of iron and titanium carbides nanoparticles reinforcements during the mechanosynthesis Cu-10Sn-15Ti/diamonds composite powders from a mixture of blended Cu/Sn/Ti powders and synthetic diamonds (10 wt%) was studied in this work. The analysis of the microstructure evolution showed that mechanical alloying performed at high-energy ball milling (600 rpm) allows developing different metastable phases depending on the SA content and milling time. For 3 wt% of SA, XRD patterns revealed a metastable Cu(Sn) solid solution is produced after 5 h of MA while Fe2.939O4, FeTiO3 and TiH0.66 nanophases were formed for milling times higher than 15 h as a result of degradation of the SA in form of gaseous products (CO, CO2, H-2, and lighter hydrocarbons (HC's)). XRD confirm that the release of these gases, along the SA degradation, and high carbon content carbon favors the carbothermic reduction of Fe2.939O4 for producing amorphous Fe3C nanoparticles at low-temperature thanks to the high-energy transferred in each impact during the MA process. For 1 wt% of SA, XRD patterns showed the formation of Cu (Ti, Sn), from the very beginning of the process (5 h), is accompanied by the release of carboxyl groups (-COOH) and crystallization of long heptadecane chains, CH3(CH2)(15)CH3. The high boiling point of this heptadecane chains and the low Fe released during milling, produces a lower content of amorphous Fe3C nanoparticles. DSC and SAED patterns performed in the mixture of both alloyed powders after heating up to 1000 degrees C showed the carbothermic reduction of FeTiO3 for producing TiC nanoparticles takes place preferably when a 3 wt% of SA is used. In both cases, the resulting alloyed powders are composed by a mixture of crystalline Cu13.7Sn + Fe + Fe3C + C + TiC phases with an Fe, and Fe3C and TiC content lower in the case of the powders processed with 1 wt% SA. The development of this dissimilar Fe3C and TiC content produces the mixture with 3 wt% of SA shows a higher stiffness.
10.1016-j.ijrmhm.2021.105503	-1		Copper-Tungsten (Cu-W) composites are promising materials for electrical and thermal applications. Manufacturing the desired Cu-W composites with full densification and a homogenous microstructure remains difficult, however, owing to the lack of mutual solubility, poor wettability, and the large difference in melting temperature between W and Cu. Here, a fully dense homogenous bulk Cu-W composite with a three-dimensional bicontinuous interpenetrating-phase architecture is fabricated by liquid metal dealloying (LMD) method, which involves immersing the Ni-W alloy in a molten metal Cu bath . The microstructure evolution mechanisms and the dealloying kinetics from a Ni-W precursor alloy to Cu-W composite are investigated. The synthesized Cu-W composite structure showed morphology variations depending on the dealloying time. The coarsening mechanism of the W ligaments during dealloying were analyzed based on curvature-driven surface smoothening and Rayleigh instability controlled ligament pinch-off process.
10.1016-j.ijrmhm.2021.105648	-1		Tungsten-copper (W-Cu) composites/pseudo alloys with excellent properties are extremely desirable for applications as electrode materials, functional graded materials, electronic packaging materials, electrical contacts, as well as other aerospace and military candidates. This paper reviewed the recent progress on fabrication techniques, microstructure and property regulation that ensure high-performance W-Cu alloys. Besides the well-developed traditional powder metallurgy including the parameter modification, powder pre-treatment and severe plastic deformation post-treatment, extensive novel sintering or manufacturing techniques including microwave sintering, spark plasma sintering, field-assisted sintering and additive manufacturing of W-Cu alloys are reviewed, along with various chemical methods for nano-powder synthesis. Subsequently, the microstructure and property regulation by pure metal elements and introduction of second phases with great details are provided. Based on the review with all-sided perspectives for W-Cu alloys, future developments and potential research challenges for W-Cu alloys are summarized and proposed finally.
10.1016-j.ijrmhm.2021.105735	16	wear; composite; composites; powders; milling; particles; powder; wt; sliding; friction; hardness; matrix; mechanical; surface; properties	Nanostructured W-31wt%Cu composite was for the first time produced via magnetic pulse compaction from bimetallic particles obtained using electric explosion of intertwisted copper/tungsten wires in argon and then characterized for microstructures, mechanical strength and tribological behavior at high temperatures. Microstructure of the composite is characterized by recrystallized copper grains with mean grain size of 59 +/- 3 nm and unreacted spherical tungsten particles. The composite density was in the range 93-99%. Flexural and compression strengths were 560 +/- 10 and 1035 +/- 150 MPa, respectively. Tribological high temperature tests showed that this composite develops reduced wear starting from the testing at 250 degrees C. Such an adaptation mechanisms is related to generation of copper tungstate CuWO4 on the worn surfaces.
10.1016-j.ijrmhm.2022.105857	16	wear; composite; composites; powders; milling; particles; powder; wt; sliding; friction; hardness; matrix; mechanical; surface; properties	In the current study, a novel approach is proposed as a method for producing Tungsten Copper composite with functionally gradient structure. In this process, a green tungsten powder compact is sintered using a special designed induction sintering set up with variable velocities to create a gradient structure. Then, the copper is infiltrated into the sintered graded tungsten scaffold at 1200 degrees C at hydrogen atmosphere. To investigate the applicability of the process, tungsten powder is pressed and the compact is sintered using induction selective sintering with variable speeds (V1-V4). Tungsten skeleton was infiltrated with copper and W-Cu composite is produced. The mechanical properties, microstructure, and electrical conductivity at different zones were examined. Corresponding to the gradient structure, the composite showed gradients in hardness and electrical conductivity. The microhardness is varied from 219 HV to 330 HV, and electrical conductivities changed from 15 to 33%IACS. This method seems to be very interesting and promising for future industrial applications.
10.1016-j.ijrmhm.2022.105866	-1		This paper presents the results of the investigation of the microstructure and properties of copper-tungsten coatings with different compositions on aluminum alloy substrates. Coatings were obtained by cold spray method using powder mixtures as feedstock. The effect of the powder mixture composition on the deposition efficiency and the tungsten content in the coating have been studied. X-ray diffraction analysis was used to investigate the phase composition and to reveal the peculiarities of changes in the crystalline structure of copper and tungsten particles after cold spraying in relation to the coating composition. Using the method of instrumental indentation on cross-sections of the coatings mechanical properties were measured. It was shown that increasing of tungsten content in the coatings contributes to increasing the microhardness and Young's modulus of the coatings. The mapping images showed that all coatings were characterized by non-uniformity of mechanical properties over the cross-section. The bonding strength of coatings significantly increases with increasing tungsten content in the feedstock. Cu-W coatings are characterized by lower specific wear rate values and higher coefficients of friction under dry sliding wear conditions in a ball-on-flat mode compared to pure copper coating.
10.1016-j.ijrmhm.2022.105929	-1		In this work, ultrafine-grained Wf/WCu composites have been developed in this work using skeleton pre -sintering at respective 1050 & DEG;C, 1150 ?, 1250 ? and 1350 ? followed by infiltration under a reductive hydrogen atmosphere. The resulted microstructure including sinterability, grain orientation distribution and phase constituents, the resulted mechanical properties including microhardness and compressive behaviors, as well as the resulted electrical properties including electrical conductivity and high-voltage arcing resistant be-haviors were systematically investigated in comparison. Results revealed that the composite pre-sintered at 1250 & DEG;C exhibited the best comprehensive properties including the highest hardness of 659 HV0.05 for Wf and 267 HV0.05 for WCu matrix, the highest compressive strength of 1004.6 MPa with pronounced deformation plasticity of 25.8%, as well as a good electrical conductivity of 24.4 %IACS and the highest electrical breakdown strength of 6.80 x 107 V/m.
10.1016-j.ijrmhm.2022.105947	17	wear; composites; coating; friction; composite; coatings; surface; tribological; properties; wear resistance; resistance; powder; sliding; matrix; wear rate	A dense and uniform W-15Cu composite material was successfully prepared by adding different amounts of silver as the active agent followed by direct sintering and infiltration. The effects of silver additive content on the microstructure and properties of W-15Cu composites under the prefabricated tungsten skeleton re-osmosis copper process and direct sintering infiltration were studied by scanning electron microscopy (SEM), X-ray diffractometer and laser thermal conductivity analyzer. When using direct infiltration sintering, adding an appropriate amount of silver eliminated pores and promoted densification, thereby increasing the relative density of tungsten copper composites. When the silver content was 2.0 wt%, the relative density was 96.58%, the thermal conductivity was up to 203.43 W/m.K, and the conductivity was 31.2% IACS. Compared with the W-15Cu composite material (26.4% IACS) prepared at the same process temperature, the conductivity of W-2.0Ag13Cu was increased by about 18.2%, and the Vickers hardness was 262 HV. The fracture morphology analysis of the tungsten-copper composites showed that the addition of Ag enhanced the interfacial bonding of the sintered composite materials and formed an ideal tungsten-copper network structure. The fracture modes were the ductile fracture of the Cu-Ag matrix and the brittle fracture of the W phase.
10.1016-j.ijrmhm.2023.106315	-1		In this paper, Cu-W alloys with different TiC additions were prepared by wire arc additive manufacturing (WAAM) technology with Cold Metal Transfer (CMT) melting copper-based flux cored wire. In the additive manufacturing process, W and TiC with high melting point directly transited to the molten pool as solid phase. When the addition of TiC was small, most of TiC was gathered around the W particles in Cu-W alloys, which was conducive to enhancing interface bonding strength . With the increased of TiC content, the electrical conductivity of Cu-W alloys was decreased, microhardness and high temperature wear resistance were increased. When the addition of TiC was more than 3 wt%, the agglomeration of TiC degrades the performance of Cu-W alloys. Cu-W alloys with 3 wt% TiC addition show the best performance, includes high microhardness and high wear resistance with low loss of electrical conductivity.
10.1016-j.ijrmhm.2023.106402	-1		In this work, TiBN and W were used as reinforced phases for Cu-based electrical contact materials. The microstructure, resistivity and arc corrosion resistance of Cu/TiBN and Cu/W alloys were investigated to understand the effect of TiBN and W doping on Cu/TiBN and Cu/W electrical contacts, respectively. Significant improvement in electrical conductivity, oxidation resistance and arc corrosion resistance of copper-based alloy was observed by TiBN reinforcement. Cu/TiBN composites showed good corrosion resistance to arc corrosion under atmospheric and salt spray conditions. The results showed the presence of large amount of TixOy, B2O3, N2 and other substances in Cu/TiBN system which are responsible for the improvement of arc corrosion resistance of Cu/TiBN system. The new Cu/TiBN electrical contact material showed great potential due to its excellent mechanical properties and arc corrosion resistance.
10.1016-j.ijrmhm.2023.106542	-1		The W skeletons were pressed by the cold isostatic pressing process, and CuW alloys with different TiB2 contents were prepared by the sintering and infiltration method. The effects of TiB2 addition on the microstructures, properties, vacuum breakdown performance, and arc motion characteristics of CuW alloys were investigated. The results show that the conductivity of CuW alloy decreases with the addition of TiB2, while the hardness increases. Compared with CuW alloy, this method improves the breakdown strength, reduces the chopping current and extends the arc life of CuW alloy. The anti-arc erosion performance of CuW alloy with the addition of TiB2 was enhanced. For CuW alloy containing TiB2, the electric breakdown occurs on the TiB2 phase at the edge of the W phase, the cathode spots are split, the arc is effectively scattered, and the ablation area after multiple breakdowns is larger, but the erosion pits are shallow and dispersed.
10.1016-j.ijrmhm.2024.106761	14	strength; properties; conductivity; electrical; mechanical; cu-; grain; mpa; electrical conductivity; aging; precipitation; phase; mechanical properties; tensile; phases	This study addresses the urgent problem of developing high-performance metal-based conductor materials capable of adapting to complex working environments. A novel method, called Accumulative Hot Pressing Roll Bonding (AHRB), is proposed for fabricating Cu/Mo/NGs multilayer composite materials. Through repetitive cold rolling and hot-pressing operations, nanoscale metal-based layered materials with thicknesses in the range of hundreds of nanometers are successfully obtained. This material features a multilayered interconnected net structure with Mo2C as the core and CuMo alloy as the framework. The layers are dislocated and connected to each other. The mechanical properties of the materials are significantly improved due to heterogeneous strengthening and grain refinement. The material achieves a tensile strength of 854 MPa, while the conductivity remains stable between 55% similar to 60% IACS. The reaction between NGs and Mo leads to the formation of an Mo2C interface, while the hot-pressing operation promotes the formation of a CuMo diffusion interface. These two interfaces enhance the interlayer forces of the composites, thereby improving the material's integrity. The investigation of Cu/Mo/NGs multilayer composite materials presents a novel approach for alloying refractory metals Mo and Cu, offering promising prospects for future engineering applications.
10.1016-j.ijrmhm.2024.106926	-1		Molybdenum-copper (Mo-Cu) composites have a low coefficient of thermal expansion, good electrical and thermal conductivity and mechanical properties, and are widely used in microelectronic packaging heat dissipation materials, aerospace and other fields. Due to the large difference in the properties of Mo and Cu, the deformation of MoCu composites is difficult. At present, there is a lack of research on the deformation process and property changes of MoCu composites with large deformation. In this study, 74 % MoCu30 composites with large deformation are prepared by cyclic warm rolling, and the deformed materials have excellent mechanical and physical properties, and the evolution of the microstructure of the composites during the deformation process is described.
10.1016-j.ijrmhm.2024.107030	-1		In the zipper manufacturing industry, cemented carbide (WC-Co) tools are typically used in shearing operations of pre-formed Cu-Zn alloy wire (15 wt% Zn) to form zipper elements. Despite its superior hardness, the WC-Co becomes gradually worn when shearing the alloy. Paradoxically, the WC and Co binder, despite their vastly different hardness, become worn at the same rate and to an even level, resulting in a smooth tool surface. Highresolution analysis of worn tools from zipper production and simplified tribological tests mimicking the sliding involved have led to several insights about the wear. The wear likely occurs through oxidative mechanisms and decreases with increasing Zn content in the alloy since Zn consumes available oxygen in the contact. In the present study, the oxidative nature of the wear is further analysed. The wear of WC-Co is investigated when sliding against pure Cu in different atmospheres, using a sliding test rig equipped with a controlled atmospheric chamber. The chamber is flushed with nitrogen gas to enable wear testing in an oxygen deficient environment. In addition, tests in flowing and stagnant air are performed to study the effects of an air flow on the wear. The wear is analysed using scanning electron microscopy, energy dispersive x-ray spectroscopy and optical surface profilometry. The visual appearances and chemical compositions of the wear surfaces were very similar after sliding against pure Cu in the different atmospheres, indicating that the same wear mechanisms had been active. In contrast, the wear rate differed significantly between the different atmospheres, being lowest in the oxygen deficient atmosphere and highest in flowing air. This indicates that the wear is oxidative, and that sliding in an oxygen deficient atmosphere has a similar effect of reducing wear as the addition of Zn has in Cu-Zn alloys.
10.1016-j.ijrmhm.2025.107053	-1		Addressing the poor cutting stability and low lifespan of copper-tin ultra-thin diamond grinding wheels for CSP (Chip Scale Package) chip package cutting, this paper investigates the growth mechanism and evolution patterns of twin phase and high-tin phases of DC(direct current)-sintered Cu-Sn pre-alloyed binder as a function of the sintering temperature and heat preservation time. The study also demonstrates the correspondence between cutting performance and microstructure, establishing a theoretical foundation for the microstructure control and performance design of ultra-thin diamond grinding wheels for advanced chip package cutting. The research indicates that the twin phase are primarily formed during the heat-up stage of the sintering process, and their size grows significantly as the insulation time increases, while the high-tin phase evolves from a discontinuous reticulated structure to a massive structure. Besides, the dynamic hardness and elastic modulus change mechanism of the microstructure of copper-tin binder is discussed in this paper. The dynamic hardness and elastic modulus of the copper-tin binder decline in general as the sintering temperature rises, and the dynamic hardness of the twins climbs and then reduces, while the elastic modulus rises and then falls. Characterization and analysis of cutting parameters, fracture surfaces, and chip formation at different sintering temperatures lead to the following conclusions: with the increase of sintering temperature, the chip size, cutting current, and wear of the single-crystal silicon all initially increase and then decrease. The grinding wheel sintered at 470 degrees C exhibits the best overall cutting performance and lifespan. Compared with ordinary copper-tin grinding wheels, the twin crystal grain distribution in the bond structure of copper-tin pre-alloyed powder sintered grinding wheels is more uniform, providing a more stable cutting process and longer cutting lifespan.
10.1016-j.ijrmhm.2025.107067	14	strength; properties; conductivity; electrical; mechanical; cu-; grain; mpa; electrical conductivity; aging; precipitation; phase; mechanical properties; tensile; phases	In this work, TiC was introduced into Cu-4.5Ti alloy by in situ Ti-graphite reaction and its influence on the microstructure and properties was studied. It was found that the addition of 0.05 wt% graphite into the melt can synthesize evenly distributed TiC particles in the alloy. Moreover, the formation of TiC beneficially optimizes the distribution of Cu4Ti phase in the as-cast alloy. Simultaneously, Compared to Cu-4.5Ti alloy, TiC particles promote the precipitation and growth of Cu4Ti nano-phase during aging, refined the grains of the matrix, and significantly improved the plasticity and electrical conductivity of the alloy. The prepared Cu-4.5Ti-0.05C alloy achieves an optimum hardness of 347.82 HV, electrical conductivity of 16 %IACS, tensile strength of 929.14 MPa, and elongation of 6.3 %.
10.1016-j.ijrmhm.2025.107152	-1		Preparing Cu-Nb alloys on copper substrate by laser directed energy deposition (LDED) can improve the ablative resistance effectively. However, the mechanical properties of the Cu-Nb alloys deteriorate due to the weak Cu-Nb interfacial bonding. To address this challenge, we propose a strategy that an interphase TiO is introduced to optimize the interface structure. Adding Ti element can significantly transform the morphology of the Nb from cellular structure to fine dendrite. It was found that the formation of TiO interphase can transform the incoherent Cu/Nb interface into the semi-coherent Cu/TiO/Nb interface that the dislocations can transmit across more easily. Therefore, the Cu-Nb-Ti deposited alloys exhibit higher total elongation. In addition, the CuNb-Ti deposited alloys exhibit higher strength due to the grain boundary strengthening and solute solution strengthening, and the Cu-Nb-1.5Ti deposited alloy achieves the most excellent synthetic performance.
10.1016-j.ijrmhm.2025.107164	-1		The goal of this study was to explore the potential application of Cu-Ta-alloy shaped-charged jets to anti-armor operations, as well as to fill some of the research gaps in this field. The effects of composition ratios and microstructures on the penetration performance of Cu-Ta jets were investigated. Cu-Ta alloys with Ta concentrations of 20 wt% (Cu-20Ta), 40 wt% (Cu-40Ta), and 80 wt% (Cu-80Ta) were prepared. The materials were analysed using scanning electron microscopy, a universal material testing machine, and a split Hopkinson pressure bar. The morphologies and penetration performance of the Cu-Ta jets were characterized by pulsed Xray and static penetration tests. The results indicated that all three materials met the design requirements. The quasi-static compression strengths of the Cu-20Ta, Cu-40Ta, and Cu-80Ta materials were 76.6 %, 140.1 %, and 551.6 % greater, respectively, than that of pure T2 copper. All three materials could form jets with good morphologies. The penetration depths of the three jets first increased and then decreased as the Ta concentration increased. The penetration depths of the Cu-20Ta, Cu-40Ta, and Cu-80Ta jets changed by 15.1 %, 26.1 %, and-56.4 %, respectively, from that of a pure T2 copper jet. These results explain the mechanisms that governed the penetration performance of the Cu-Ta alloys, and it was determined that the ideal tantalumconcentration range for the Cu-Ta shaped-charge jets was centred around 40 wt%. The results of this study demonstrate the potential for Cu-Ta-alloy utilization in anti-armor operations and lay a foundation for the application of Cu-Ta alloys in the anti-armor field.
10.1016-j.ijrmhm.2025.107401	14	strength; properties; conductivity; electrical; mechanical; cu-; grain; mpa; electrical conductivity; aging; precipitation; phase; mechanical properties; tensile; phases	Tungsten-copper (W-Cu) composites had received attention due to their high melting point (W) and excellent conductivity/thermal conductivity (Cu), and were widely used in high-temperature electrical contact materials. However, their intrinsic immiscibility limited the achievement of densification via conventional powder metallurgy, yielding sintered densities of only 85-92 % of theoretical values. This study proposed a submicron coating engineering strategy to address this challenge. By chemically precipitating and hydrogen-reducing a CuSO4 precursor, submicron W coatings were constructed on micron-sized W particles (4-5 mu m). After calcination at 450 degrees C and hydrogen reduction at 900 degrees C, the coated composite powders were liquid-phase sintered at 1300 degrees C for 2 h, achieving a relative density of 97.8 %, which significantly surpassed the value of conventional methods (84.9 %). Microstructural analysis revealed that the submicron coatings prolonged the particle rearrangement phase by isolating micron-sized W grains, while the high surface activity of submicron particles enhanced interfacial diffusion, synergistically optimizing densification. The sintered body without impurity phase exhibited an electrical conductivity of 54.7 % IACS (comparable to 56.0 % for infiltration products), a 73 % hardness increase (179.8 HB). This strategy overcame the densification bottlenecks in immiscible systems by regulating interparticle interactions and offered a universal solution for analogous systems (e.g., Mo-Cu, W-Ag).
10.1016-j.ijsolstr.2011.03.007	4	transformation; martensite; martensitic; phase; shape; beta; memory; shape memory; temperature; temperatures; martensitic transformation; gamma; transformation temperatures; effect; thermal	A detailed morphology of the twinned-to-detwinned interface in microstructure of 2H-martensite phase of the Cu-Al-Ni shape memory alloy is observed by optical methods (optical microscopy, white-light interferometry). Based on these observations, a finite element model of the transition layer is constructed and applied to calculate the elastic stress distribution inside the observed microstructure. The results show that the real micromorphology does not correspond to the minimum of the sum of the elastic and surface energy, and that the maxima of the stress field necessary for the existence of this morphology are comparable to the elasticity limits of the 2H-martensite.
10.1016-j.ijsolstr.2012.01.005	-1		Experimental studies on ductility of selected metals differing mechanical properties under strain rates between 4 x 10(3) and 2 x 10(4) s(-1) are presented in this work. The electromagnetic expanding ring experiment was used as the primary tool for examining the ductility behaviour of metals. Through a use of the Phantom v12 digital high-speed camera and specialised TEMA Automotive software, rings expansion velocities were determined with satisfactory accuracy for all ring tests. In this paper, the experimental observations on cold-rolled copper Cu-ETP, aluminium alloy Al 7075, barrel steel and tungsten heavy alloy are reported. Ductility of studied materials was estimated by measuring changes in cross-sectional areas in the uniform strain portions of the recovered ring fragments. In a similar way the metals ductility was defined at the conventional tensile test condition. Moreover, results of analogue investigation for static and dynamic loading at the temperature of about -40 degrees C were described. The experimental observations mainly revealed the different ductility behaviour of metals tested at applied dynamic loadings: Cu-ETP and barrel steel demonstrated an increase in ductility, whereas aluminium alloy Al 7075 and tungsten heavy alloy were characterised by lower ductility in comparison to static loading. These results appear to be partially in contrast with the observations reported recently by some other investigators.
10.1016-j.ijsolstr.2012.01.017	4	transformation; martensite; martensitic; phase; shape; beta; memory; shape memory; temperature; temperatures; martensitic transformation; gamma; transformation temperatures; effect; thermal	This paper concerns the behavior of Cu-Al-Be polycrystalline shape memory alloys under cyclic thermomechanical loadings. Sometimes, as shown by many experimental observations, a permanent inelastic strain occurs and increases with the number of cycles. A series of cyclic thermomechanical tests has been carried out and the origin of the residual strain has been identified as residual martensite. These observations have been used to develop a 3D macroscopic model for the superelasticity and stress assisted memory effect of SMAs able to describe the evolution of permanent inelastic strain during cycles. The model has been implemented in a finite elements code and used to simulate the behavior of antagonistic actuators based on SMA springs under cyclic thermomechanical loading with a residual displacement appearance.
10.1016-j.ijsolstr.2016.07.023	-1		Crystal plasticity finite element simulations of tensile tests on thin polycrystalline samples with grain orientations representative of the microstructure in Al-Cu-Li rolled sheets are carried out to study the influence of grain-to-grain interactions on plastic strain localization. Anisotropic work-hardening and rate sensitivity of the material behavior are assumed. The grains are modeled as thin platelets in the through thickness direction, elongated in the rolling and transverse directions. The only distinctive feature of the present simulations with respect to standard crystal plasticity calculations is the enforcement of tangential continuity conditions on the elastic and plastic distortion rates along grain boundaries, which introduces grain-to-grain interactions and renders the simulations nonlocal. Whereas standard crystal plasticity calculations do not predict any significant plastic strain pattern, slanted shear bands spontaneously emerge throughout the sample in the simulations involving tangential continuity, in agreement with experimental observations. Also in agreement with experimental data, shear banding is delayed when the tensile axis shifts from rolling to transverse direction, and the trend to shear banding is enhanced when grain thickness is decreased, particularly in loading along the rolling direction.
10.1016-j.ijsolstr.2021.01.015	3	sma; shape; shape memory; memory; smas; superelastic; bars; damping; cu-al-mn; mechanical; bending; applications; numerical; sma bars; material	Shape Memory Alloys (SMAs) are widely used in endodontics as instruments for root canal preparation namely endodontic rotary files. Despite their high performances, compared to stainless steel instruments, it is still possible to enhance their cutting efficiency by acting on their shape and material properties. As an example, increasing the exhibited reversible martensitic transformation strain makes them more flexible without decreasing their mechanical strength . It becomes possible with single crystal SMAs. Cubased (Cu-Al-Be, Cu-Zn-Al, Cu-Al-Mn) single crystal SMAs start emerging and can reach about 12% of martensitic transformation strain, in addition to their interesting antimicrobial properties. This study investigates, both numerically and experimentally, the development of endodontic files made of Cubased single crystal SMAs. The numerical analysis is carried out by the finite element method. The geometry of the instrument is parameterized. Depending on the applied boundary conditions, bending, torsion, or combined bending-torsion loadings are represented. A micromechanical constitutive law is implemented in Abaqus via the UMAT subroutine to describe the thermomechanical behavior of the Cubased single crystal SMA. Following the thus obtained numerical results, Coltene-Micromega company has manufactured endodontic file prototypes made of Cu-Al-Be single crystal SMA. A specific setup applying the same boundary conditions of torsion-bending loading is used to characterize these SMA file prototypes. The good agreement between experimental and numerical responses, for a combined bending-torsion loading, proves the relevance of the proposed approach and the pertinence of considering Cu-based SMAs for endodontic file applications.
10.1016-j.ijthermalsci.2007.07.012	4	transformation; martensite; martensitic; phase; shape; beta; memory; shape memory; temperature; temperatures; martensitic transformation; gamma; transformation temperatures; effect; thermal	The reverse and forward transformation temperatures and oxidation behavior of neutron irradiated CuAlNi shape memory alloy have been investigated. The alloy was irradiated for 3.6 and 7.2 ks with thermal neutron flux at 8 x 10(12) n cm(-2) s(-1), E > 1 MeV. It was seen from differential scanning calorimetry (DSC) that the forward and reverse transformation temperatures of the martensite double left right arrow austenite were decreased with the applied radiation. Enthalpies of transformation (Delta H heating and Delta H cooling) increase with neutron irradiation. Thermogravimetric measurements were carried out to investigate the kinetics of oxidation. The activation energy of oxidation for alloy was calculated using thermogravimetric data.
10.1016-j.indcrop.2025.121230	2	corrosion; surface; film; electrochemical; films; spectroscopy; layer; current; solution; potential; resistance; composition; x-ray; ions; showed	Rationale: Copper alloys are widely used in industrial applications due to their excellent thermal and electrical conductivity, but they suffer severe corrosion in acidic environments, necessitating the development of efficient and eco-friendly corrosion inhibitors to protect copper alloys from corrosion. Objective: This study aims to explore the corrosion inhibition performance and intermolecular synergistic behavior of licorice (Glycyrrhiza uralensis Fisch .) leaf extract (LE), a waste-derived natural product, for copper alloys in 0.5 mol/L H2SO4 solution. Materials and methods: Waste licorice leaves are processed via Soxhlet extraction using pure water as a solvent to prepare LE, which was confirmed to contain glycyrrhizic acid and glabridin as the main active components. Electrochemical measurements, surface characterizations, and theoretical calculations are employed to evaluate the corrosion inhibition efficiency and mechanism. Conclusion: Results show that LE exhibits corrosion inhibition ability, with a maximum efficiency of 91.2 % at 200 mg/L. When compounded with potassium iodide, the optimal efficiency increases to 95.3 % and further reaches 99.3 % after 144 h immersion. The excellent performance is attributed to the formation of complexes between LE components and Cu+, as well as insoluble copper(I) iodide (CuI) generated by I-and Cu+ on the metal surface, which together forms a dense protective film to hinder corrosive substance diffusion. Glycyrrhizic acid and glabridin demonstrate intermolecular synergism, with higher glabridin content enhancing the barrier effect of the inhibitor film. Prolonged immersion promotes the formation of a more complete and compact film, significantly improving long-term inhibition performance. This work highlights the potential of waste licorice leaf extract as an efficient, sustainable corrosion inhibitor for copper alloys in acidic media, providing insights into the synergistic mechanisms underlying its performance.
10.1016-j.inoche.2023.111308	2	corrosion; surface; film; electrochemical; films; spectroscopy; layer; current; solution; potential; resistance; composition; x-ray; ions; showed	In this research, developing a novel chitosan-Schiff base and its derivatives is a distinct and appealing synthetic route for green corrosion inhibitors to lower the rate of Cu-Ni alloy industrial corrosion. Cu-Ni alloy is a material of choice for condensers and heat exchangers, where seawater is used as a coolant and in desalination plants. Therefore, a novel chitosan-sodium pyruvate (Chi-SP) polymer was successfully prepared through the condensation reaction of chitosan with sodium pyruvate. (Chi-SP) polymer is tailored into the hydrophobic core of beta-cyclodextrin (CD) by two routes (chemically and physically) to give a novel Chi-SP/beta-CD inclusion complex (IC), Chi-SP/beta-CD physical mixture (PM), respectively. Further, A composite of Chi-SP encapsulating titanium oxide (TiO2) with nanometer size has been synthesized by a one-pot reaction. The physicochemical properties and the corrosion inhibition efficiency (CIE) of Chi-SP, Chi-SP/beta-CDIC, Chi-SP/beta-CD PM, and Chi-SP/TiO2 were performed. The corrosion rate (CR) and inhibitor efficiency (IE) of Cu-Ni alloy in HCl (1 M) using Chi-SP, PM, IC, and the nanocomposite were found to be (82.53, 61.63, 65.56, and 62.94) % and (54.1, 65.7, 63.5, and 65)%, respectively. These findings reveal that the Chi-SP/TiO2 molecules have many polar hydroxyl groups which can contribute to the chemisorption and physisorption of the inhibitor on the alloy surface. As well as, the TiO2 in an aqueous solution convert into Ti4+ (cation ions) adsorbed on the negatively charged electrode surface, which increases the adsorption of the nanocomposite on the electrode surface and increases the protection layer.
10.1016-j.intermet.2004.04.003	13	clusters; atomic; glass; atoms; composition; dynamics; metallic; icosahedral; glasses; simulations; molecular; cu-zr; molecular dynamics; metallic glasses; structural	Based on the embedded-atom method, a constant-pressure, constant-temperature molecular dynamics technique is applied to obtain an atomic description of glass formation process in eutectic Cu40Ag60 alloy. By using radial distribution function and pair analysis methods, the structure and glass forming ability of this alloy is studied by quenching from the liquid at different cooling rates (1 x 10(11), 1 x 10(12), 5 x 10(12), 1 x 10(13) and 1 x 10(14) K/s). It is observed that the retention of amorphous structure requires extremely high cooling rates. Structure analyses of the alloys in the simulations reveal the evolvement of the different clusters at various quenching rate during the quenching process.
10.1016-j.intermet.2004.04.016	-1		We report the fabrication of the Cu-Ni-Zr-Ti bulk amorphous alloys by warm rolling of amorphous powders, which have been prepared by a high-pressure gas atomization. The Cu54Ni6Zr22Ti18 amorphous powders obtained by a high-pressure He gas atomization method has a wide supercooled liquid region of 53 K. By warm rolling of amorphous powders in the supercooled liquid state, a fully amorphous Cu54Ni6Zr22Ti18 alloy is successfully synthesized. The conditions for rolling are obtained from the time-temperature-transformation curve by measuring the time for the onset of crystallization during isothermal annealing in differential scanning calorimetry. The rolled bulk amorphous Cu54Ni6Zr22Ti18 alloy exhibited high strength about 1.9 GPa, which is against similar to that obtained in the as-cast bulk amorphous alloy.
10.1016-j.intermet.2004.04.023	-1		The crystallization behavior, the thermal stability and the microhardness of Cu60ZrxTi40-x amorphous alloys (x = 15, 20, 22, 25, 30) prepared by melt-spinning have been studied by means of differential scanning calorimetry (DSC), differential thermal analysis (DTA), X-ray diffraction (XRD) and microhardness tests. DSC analysis have confirmed the existence of glass transition, followed by a supercooled liquid region in all the compositions. However, depending on the Zr content, different crystallization behavior has been observed. The apparent activation energies of the crystallization processes have been determined and the obtained values indicate high thermal stability for all the alloys. XRD-patterns of the as-quenched samples showed a broad symmetric halo typical of a fully amorphous structure. Independently of the composition, after the first crystallization stage the XRD patterns present a structure similar to that of an amorphous one. But the final developed microstructure depends on the composition of the alloys. The addition of Zr has not shown significant differences in microhardness of the amorphous alloys, although they have exhibited good mechanical properties.
10.1016-j.intermet.2004.04.033	7	irradiation; shear; grain; ta; deformation; size; radiation; voids; nanocrystalline; simulations; similar; void; temperature; irradiated; boundaries	The free volume model for flow in metallic glasses predicts a significant increase in free volume at the onset of plastic deformation. The details of these structural changes are unclear, however, particularly during strain localization in shear bands. In this study, the free volume changes associated with inhomogeneous plastic deformation of a Cu-based bulk metallic glass were examined using positron annihilation spectroscopy (PAS). PAS results indicated that there was a distribution of free volume site sizes in both the as-quenched and rolled glasses, and that the concentration of larger sites increased with deformation. Differential scanning calorimetry was also used to observe the glass transition behaviors of Cu- and Zr-based glasses after rolling and annealing. Annealing resulted in an increase in the height of the endothermic glass transition peak, consistent with structural relaxation relative to the as-quenched material. Deformation resulted in both a lower endothermic peak height and an earlier and deeper exothermic peak associated with structural relaxation, indicating a more disordered structure with more free volume.
10.1016-j.intermet.2004.07.002	-1		The present paper is concerned with the formation of the Cu-based Cu-Zr-Al bulk metallic glasses (BMGs). Composition optimization for BMG formation was realized by using an 'e/a-variant criterion' that had been successfully applied in the Zr-Al-Ni and Zr-Al-Co systems. This criterion was incorporated into the ternary phase diagram by constructing a composition line (Cu61.8Zr38.2)(1-x)Al-x, which was defined by linking the optimum binary composition (Cu61.8Zr38.2, a deep eutectic in this case) and the third element. BMGs were obtained within an e/a span from 1.24 to 1.3 along this composition line. Thermal analysis results indicate that these BMGs manifest increased thermal stability and glass forming ability (GFA) with increasing e/a ratios. The maximum appears in Cu58.1Zr35.9Al6 with the a/a value of 1.3 which is the highest among our samples. The characteristic thermal parameters of this BMG are T-g = 760 K, T-g/T-l = 0.648, which are all superior to those reported for the known Cu55Zr40Al5 BMG.
10.1016-j.intermet.2004.10.005	-1		The phase separation in the bee phase of the Cu-Al-Ni system at 600-700 degrees C was investigated mainly by energy dispersion X-ray spectrometry (EDS) and differential scanning, calorimetry (DSC). The compositions of the beta(1) (A2 or B2: Cu-rich), beta(2) (B2: NiAl-rich) and gamma (gamma-brass type) phases in equilibrium were determined. It was found that there is a beta(1) + beta(2) miscibility gap in the beta phase region as previously reported by Alexander. It was confirmed by means of high temperature in situ TEM observation that this miscibility gap consists of the B2+B2 phases but not the A2+B2 phases which is sometimes observed in many other Ni-Al and Co-Al base ternary bee alloys. Thermodynamic calculation was performed which indicates that this characteristic feature suggests that the beta(1) (B2) + beta(2) (B2) miscibility gap is a part of a Cu-rich B2 + NiAl-rich B2 miscibility gap island formed around the center of the composition triangle of the isothermal section. The phase separation in the beta phase region and the stability of the ordered bcc alummide are presented and discussed.
10.1016-j.intermet.2005.01.010	-1		The thermal stability and crystallization kinetics of Cu47Ti33Zr11Ni8Si1 gas atomized powder (GAP) and composite powder reinforced with 25 vol.% nanosized Cu second phase particles introduced by ball milling was studied by differential scanning calorimetry in the mode of continuous heating and isothermal annealing. Ball milling leads to successful incorporation of Cu particles within the GAP matrix and hence offers itself as a useful technique to prepare composite microstructures. In the case of continuous heating, both the glass transition temperature T-g and the crystallization temperature T-x display a strong dependence on the heating rate. The activation energy, as determined by the Kissinger equation, for the first order transformation was found to be almost identical for the GAP (3.53 +/- 0.12 eV) and composite powders (3.59 +/- 0.06 eV). The isothermal transformation kinetics were modeled by the Johnson-Mehl-Avrami (JMA) equation. The values of the JMA exponent imply that the crystallization of the metallic glass GAP as well as the composite powder is governed by diffusion-controlled three-dimensional growth . The activation energy of crystallization derived from isothermal annealing experiments is nearly the same for the GAP (3.69 +/- 0.20 eV) and the composite powders (3.78 +/- 0. 10 eV). The addition of Cut particles does not noticeably affect the crystallization kinetics of the amorphous matrix composites.
10.1016-j.intermet.2005.12.009	-1		Superplastic deformation and crystallization behavior of a Cu54Ni6Zr22Ti18, metallic glass were investigated. A maximum elongation of 650% was obtained at 733 K at 1 X 10(-2) s(-1) from the sheet fabricated by squeeze copper-mold casting method. At low strain rates, the strain-rate-sensitivity exponent value was close to 1, suggesting that Newtonian-like behavior governed the plastic flow. At a high strain rate around 10-2 s-1, a transition from Newtonian to non-Newtonian behavior took place with decrease in m value. Large strain hardening by crystallization occurred during the course of deformation. The strain hardening was found to be caused by crystallization according to the analyses of the relation of true stress vs. testing time, T-T-T diagram and DSC characteristics. The time periods up to the strain before strain hardening at 733 K for the Cu54Ni6Zr22Ti18 metallic glass were similar to that of the Zr65Al10Ni10Cu15 metallic glass at 696 K as 180-300 s (3-5 min). This coincidence could be explained by comparison of their T-T-T diagrams showing that the incubation times for crystallization of the Cu BMG at 733 K and for Zr BMG at 696 K are similar.
10.1016-j.intermet.2006.01.020	12	thermodynamic; ternary; phase; data; experimental; equilibria; phase equilibria; liquid; binary; experimental data; calculated; phases; literature; model; calphad	The isothermal cross-section through the ternary Cu-Ni-Zr phase diagram at 800 C was constructed by means of diffusion couples and equilibrated alloys. Two ternary phases Cu-20-40N40-60Zr20 and Cu20-25M60-65Zr15 exist in the system at this temperature. Most of the Cu-Zr and Ni-Zr binary intermetallic phases show large solubility range extending to the ternary region and the solubility ranges are determined. Although Cu10Zr7 and Ni10Zr7 binary phase have the same crystal structure oC68, both phases did not form complete solid solution phase. Electron Microprobe analysis was used to determine the phase composition.
10.1016-j.intermet.2006.04.002	13	clusters; atomic; glass; atoms; composition; dynamics; metallic; icosahedral; glasses; simulations; molecular; cu-zr; molecular dynamics; metallic glasses; structural	CuxZr1-x (x = 0.30-0.85) amorphous alloy models were constructed using molecular dynamics simulations. In order to estimate the local structures characterized by pentagonal short-range order and free volume, Voronoi polyhedra analyses were performed for the initial states and also for the deformed states of the models. Both these geometrical factors are intimately related to each other and exhibit a large influence on mechanical properties. The elastic properties tend to increase as the free volume decreases. Moreover, flow stress drastically decreases with increasing free volume content. It was found that the non-pentagonal regions, which are sources for the generation of high free volume structures, preferentially undergo irreversible atomic rearrangements in the early stage of the deformation process.
10.1016-j.intermet.2006.10.039	-1		(Cu47Zr11Ti34Ni8)(100-x) Mo-x bulk metallic glasses (BMGs) with x = 0, 1 and 2 at% were prepared by water-cooled copper mold casting. The effect of the addition of a small amount of Mo on the corrosion resistance of the Cu-based BMGs was examined by electrochemical polarization and weight loss measurement in 1 mol/L H2SO4 open to air. It is found that the corrosion resistance of Cu-based BMGs enhanced with increasing Mo content, as indicated by the decrease in passive Current density and corrosion rate with the increase in Mo content. X-ray photoelectron spectroscopy (XPS) was employed to Study the composition and the state of elements in the passive film, which revealed that the improvement of corrosion resistance of Cu-based BMGs microalloyed with Mo originated from the enrichment of ZrO2 and TiO2, but depletion in Cu- or Ni-oxide in the passive films formed during electrochemical polarization. In addition, the galvanostatic-step measurement was performed to investigate the formation kinetics of the passive films. It is demonstrated that the addition of an appropriate amount of Mo can promote the formation of the passive film on the surface.
10.1016-j.intermet.2007.04.001	-1		In this paper, ultrafine nickel-rich Cu-Ni bimetallic powders were synthesized with hydrothermal-reduction method. When polyethyleneglycol (PEG) was employed as protective agent, flake bimetallic powder particles, which have an excellent dispersibility and uniform size of 1.8-2.0 pm, can be prepared. Polyhedral powder particles, which have a uniform particle size in the range from 0.5 to 0.8 mu m, were successfully synthesized using gelatin as protective agent. By thermal analysis, it was found that the oxidation-resistance of Cu-Ni powder particles was strong. Above-mentioned flake/polyhedral bimetallic powders were mixed with inorganic binder and vehicle to make conductive thick film. The low resistivity and high adhesion strength of thick film were attributed to high densification and rough interface from interfacial reaction, respectively.
10.1016-j.intermet.2007.07.008	-1		By combining CALPHAD technique with kinetic approach, we evaluated the glass forming ability(GFA) of nine compositions of Cu-Zr and thirteen of Cu-Zr-Ti alloys in terms of critical cooling rate and fragility. The driving forces for crystallization from the undercooled liquid alloys were calculated by using Turnbull and Thompson-Spaepen (TS) Gibbs free energy approximate equations, respectively. Time-temperature-transformation (TTT) curves of these alloys were obtained with Davies-Uhlmann kinetic equations based on classical nucleation theory. With Turnbull and TS equations, the critical cooling rates are calculated to be in the range of 9.78 x 10(3)-8.23 x 10(5) K/s and 4.32 x 10(2)-3.63 x 10(4) K/s, respectively, for Cu-Zr alloys, and 1.38 x 10(2)-7.34 x 10(5) K/s and 0.64-1.36 x 10(4) K/s, respectively, for Cu-Zr-Ti alloys. The calculated fragility parameters are in the range of 6.32-9.3 for Cu-Zr binary and 5.7-8.24 ternary alloys, respectively. The comparison of the calculated results to the experimental data indicates that the cooling rate obtained with TS equation is more valid than that with Turnbull equation, and that obtained by other researchers for the evaluation of GFA. The fragility be used as parameter to evaluate relatively the GFA in an alloy system. This work suggests that the combined thermodynamic and kinetic modeling may provide an effective method for the prediction of GFA in Cu-Zr and Cu-Zr-Ti alloys.
10.1016-j.intermet.2008.12.001	4	transformation; martensite; martensitic; phase; shape; beta; memory; shape memory; temperature; temperatures; martensitic transformation; gamma; transformation temperatures; effect; thermal	The influence of gamma(2) precipitates on the MT of a Cu-22.66Al-2.98Be (at%) polycrystalline alloy was analysed by compression test, differential scanning calorimetry and microscopy. As the precipitate content (or size) increases, the stress-induced martensitic transformation occurs at higher stress levels. The thermally induced martensitic transformation is only significantly affected when the gamma(2) phase content exceeds 14%, the thermal peaks are shifted to higher temperatures and less beta phase transforms to martensite. TEM observations suggest good coherency between both phases, and dislocation bundles remain in the beta side of the gamma(2)/beta interface after the compression-induced transformation to martensite. The evolution of sigma(s) with fv gamma(2) is analysed considering a chemical and a mechanical contribution.
10.1016-j.intermet.2008.12.003	11	glass; bulk; metallic; bulk metallic; gfa; bmg; glassy; metallic glass; ability; bulk metallic glass; amorphous; addition; crystallization; mm; glass-forming	In the present study we investigate the phase formation and the thermal stability of Cu50Zr50-xTix (0 <= x <= 10) and (Cu0.5Zr0.5)(100-x)Al-x glass-forming alloys. Parameters indicating the glass-forming ability (GFA) are calculated from isochronal and isothermal calorimetric experiments. A high Ti content in the Cu-Zr-Ti alloys causes the precipitation of a metastable ternary Laves phase (C15), which does not form in Cu-Zr-Al. Accompanied with it is a significant drop in the activation energy of crystallization. Also the supercooled liquid region (Delta T-x = T-x-T-g), the reduced glass transition temperature (T-rg = T-g/T-liq), and the gamma parameter (gamma = T-x/(T-g + T-liq)) (T-x: crystallization temperature, T-g: glass transition temperature and T-liq: liquidus temperature) are sensitive to the change in the crystallization sequence. The fragility values calculated are believed to overestimate the GFA of the investigated alloys. Careful selection of the alloy composition enables the targeted precipitation of different crystalline phases.
10.1016-j.intermet.2010.02.051	11	glass; bulk; metallic; bulk metallic; gfa; bmg; glassy; metallic glass; ability; bulk metallic glass; amorphous; addition; crystallization; mm; glass-forming	In this study, (Cu0.46Zr0.46Al0.08)(100-X)Y-X (0 <= X <= 8,in at%) alloy ribbons and rods are prepared by single roller melt-spinning method and suction casting method. X-ray spectra show that the obtained alloy ribbons with X = 0, 2, 4, 8 and alloy rods with X = 0 and 4 at% Y are fully amorphous. Amorphous rod of 4 at% Y containing alloy up to 6 mm diameter can be achieved and has a large supercooled region (Delta T-X) up to 75 K. In contrast, alloy rods with either X = 2 or 8 at% Y contain small amount of crystallites. In H2SO4 solution, the Cu-Zr-Al-Y metallic glass rods form uniform oxide films on surface and have corrosion rate of 0.051-0.073 mm/yr. Pitting occurs when the glass rods are immersed in 3% NaCl solution and sea water and the corrosion rate ranges from 0.194 to 0.286 mm/yr. In all solutions, the corrosion resistance of Cu-Zr-Al-Y bulk metallic glass outperforms 304 L stainless steel.
10.1016-j.intermet.2010.03.005	-1		The effect of Si addition on the oxidation of (Cu(43)Zr(43)Al(7)Ag(7))(99.5)Si(0.5) bulk metallic glass (CZ43S-BMG) was investigated over the temperature range of 375-500 degrees C in dry air. The results generally showed that the oxidation rates of the CZ43S-BMG followed a multi-stage parabolic-rate law, and the oxidation rate constants (k(p) values) fluctuated with increasing temperature. It was found that the k(p) values of the CZ43S-BMG were slightly slower than those of the Si-free glassy alloy (Cu(43)Zr(43)Al(7)Ag(7), named as CZ43-BMG). The scales formed on the CZ43S-BMG strongly depend on temperature, consisting of 3 different modifications of ZrO(2) and CuO, and minor amounts of Cu(2)O (formed at T >= 425 degrees C) and Al(2)O(3) (only detected at 500 degrees C). In addition, the glassy substrate remained amorphous nature at T <= 400 degrees C, while it transferred to the crystalline phases of Cu(10)Zr(7), ZrAl, and ZrSi(2) after the oxidation at higher temperatures. Crown Copyright
10.1016-j.intermet.2010.03.018	-1		The temperature dependence of length change and viscous flow of the Cu36Zr48Al8Ag8 glassy alloy is examined in both the glass transition and supercooled liquid regions. Moreover, this alloy is found to exhibit phase separation rather by binodal mechanism in the glassy phase prior to crystallization. There is an apparent decrease in viscosity observed upon crystallization that is connected with the densification of the sample, but the intrinsic viscosity does not rise significantly until the initial crystallization process is almost complete. During the process the partly crystallized supercooled liquid still behaves like a fluid until a large fraction of the crystalline phase (similar to 90%) is formed. This new insight on flow behavior opens up possibilities for innovative processing of precise bulk shapes with high nanocrystal densities.
10.1016-j.intermet.2010.03.031	-1		A martensitic phase transformation from the B2 to the B19'CuZr phase in the Cu-Zr-Al bulk metallic glass (BMG) composite was induced by cryogenic treatment (CT). The martensitic transformation causes the improvements of the microhardness and the ultimate compression fracture strength . When the cryogenic treatment time was 72 h, the microhardness and the ultimate compression fracture strength of the BMG composite increased about 18.55% and 37.5%, respectively.
10.1016-j.intermet.2010.07.002	4	transformation; martensite; martensitic; phase; shape; beta; memory; shape memory; temperature; temperatures; martensitic transformation; gamma; transformation temperatures; effect; thermal	The temperature memory effects (TME) in shape memory alloys (SMA), which appear after incomplete reverse martensitic transformations, strongly modify the kinetics of successive heating runs In the present work, these TME have been studied in Cu-Al-Ni alloys by adiabatic calorimetry and optical microscopy. The influence of the different martensitic crystallographic structures, the size of the martensite variants, the physical state of the sample, as well as the number of previous partial cycles are discussed. New results in powdered samples are compared with those obtained in single crystals. The analysis of the experimental data within the frame of a simple thermodynamic model suggests the presence of a high number of martensite plates, which permits a continuous distribution of the elastic energy throughout the crystal, as a necessary condition for these thermal effects. Their knowledge is of paramount importance to improve the reliability of SMA devices.
10.1016-j.intermet.2010.08.035	-1		Two types of stress-strain behaviors were observed during tensile deformation of Cu-Zr amorphous ribbons at room temperature and at strain rates varying between 10(-3) s(-1) and 10(-5) s(-1). Experimental observations carried out using HRTEM and XRD on the extent of nano-crystallization during the deformation revealed that the extent of nano-crystallization determines the nature of stress-strain behavior. Molecular dynamics simulations (MD) were carried out to support the inference.
10.1016-j.intermet.2010.12.008	4	transformation; martensite; martensitic; phase; shape; beta; memory; shape memory; temperature; temperatures; martensitic transformation; gamma; transformation temperatures; effect; thermal	This paper presents a study of the mechanical properties of pseudoelastic Cu-Zn-Al foams. Foams of different densities were cycled in compression. The paper shows the retained/dissipated energy by the material, i.e. the area of the compression cycle, as a function of the material density. The frequency and strain amplitude, usual parameters that may influence the damping properties, are studied by evaluating the dissipated energy and the specific damping capacity. Samples cyclically tested under constrained compression conditions show a remarkable mechanical stability and reproducibility. The material does not appreciably degrade after 1000 compression cycles at room temperature. We emphasize the material does not need any thermomechanical processing or training treatment in order to present the mechanical properties detailed in the present paper.
10.1016-j.intermet.2011.01.001	13	clusters; atomic; glass; atoms; composition; dynamics; metallic; icosahedral; glasses; simulations; molecular; cu-zr; molecular dynamics; metallic glasses; structural	We report on results concerning the short-range order of Cu35Zr65, Cu50Zr50 and Cu65Zr35 Metallic Glasses (MG) by means of Reverse Monte Carlo (RMC) (based on Neutron scattering data) and Molecular Dynamics simulations (MD). For each one of these MGs, two separate structural models were created: one by the RMC method and another one by MD simulations, which were subsequently analyzed by cluster analysis. The atomic structures of the glasses are characterized by interconnected atomic clusters forming superclusters. The atomic population of the clusters varies with composition and in the Zr-rich case it exhibits some differences between the two structural models. Nevertheless, the formed superclusters are found to be identical in both models and do not depend on the specific details of the atomic interactions. Thus, they appear to have topological origin, and the influence of chemistry in terms of chemical short-range ordering is restricted to the composition of the small clusters. In addition, the partial radial distribution functions (RDFs) reveal that the atomic pair distances do not depend on the respective compositions of the systems, suggesting that the experimental shift of the RDFs when changing the stoichiometry is due only to the alterations of the relative heights of the peaks.
10.1016-j.intermet.2011.03.023	-1		The cyclic compression behavior of a Cu(45)Zr(45)Al(5)Ag(5)BMG was investigated in order to elucidate the damage initiation and growth mechanisms. The present Cu45Zr45Al5Ag5 BMG was found to have a fatigue-endurance limit of 1418 MPa and fatigue ratio of 0.77. Fracture under cyclic compression occurred in a pure shear mode. The fracture surface forms an angle of 41 degrees with respect to the loading axis. This angle was similar to the monotonic compressive fracture angle for the present BMG. The cyclic compression fracture surface displays a morphology nearly identical to the monotonic compression fracture surface. In addition to many shear bands and cracks, areas of chipping were commonly found on the outside surfaces of the fatigue specimens. An attempt was made to measure crack growth rates, and two types of crack growth behavior were found. With the first type, the growth rate decreased with cycles due to the decrease in the driving force for crack propagation. With the second type, the crack growth rate increased with cycles after chipped areas developed. The fatigue deformation process for BMGs under cyclic compression was carefully studied and rationalized.
10.1016-j.intermet.2011.07.022	-1		In this study a new approach, based on modification of surfaces by energetic ion bombardment produced through cathodic arc plasma was utilized for the production of bulk Cu-Al compounds. Alloying was done in a cyclic manner by depositing aluminum under low bias voltages, and then by enhancing diffusion/mixing by applying a high bias voltage (bombarding). During the bombarding step, substrate temperatures in a range of 750-800 degrees C can be achieved depending on the duration in a time scale of seconds where copper foils with 25 mu m thickness were used as substrates. For homogenization of the as-processed samples, a vacuum annealing heat treatment was applied at 700 degrees C for 24 h . Single phase alpha(1)-Cu solid solution, and gamma(1)-Al(4)Cu(9), delta-Al(2)Cu(3), and zeta(2)-Al(3)Cu(4) intermetallics were successfully produced. Structural and surface/cross sectional investigations of the samples were conducted with XRD, SEM and EDS measurements. The micro-hardness of the phases, was also determined.
10.1016-j.intermet.2011.07.031	13	clusters; atomic; glass; atoms; composition; dynamics; metallic; icosahedral; glasses; simulations; molecular; cu-zr; molecular dynamics; metallic glasses; structural	The study is focusing on how physical factors correlate with malleability for bulk metallic glasses (BMGs). Although great efforts have been done in these aspects, many problems still remain interesting. In this work, we investigated systematically the compositional dependence of the compressive malleability for three selected BMG samples of Cu52Hf39Al9 (C1), Cu49Hf42Al9 (C2) and Cu45Hf46Al9 (C3) in the high glass-forming Cu-Hf-Al system. Our results demonstrated that (i) with increasing of Hf content the malleability of BMGs becomes stronger, (ii) shear stress has an important impact in controlling the compressive deformation behaviors and (iii) the malleability increases linearly as the glass transition temperature and shear modulus decrease but it does not directly correlate with Poisson's ratio and glass forming ability. Finally, through two-parameter Weibull statistics we further suggest that the C3 BMG indeed exhibits a more uniform distribution on the failing strength in a more reliable manner with respect to the other C1 and C2 cases.
10.1016-j.intermet.2011.11.019	-1		We measured the temperature dependence of the apparent specific heat of Cu55Hf25Ti15Pd5 glassy alloy (metallic glass) by a differential scanning calorimetry method during continuous heating, and investigated the structural relaxation and crystallization processes. The results of structural evolution obtained by transmission electron microscopy are discussed in line with the differential scanning calorimetry data. Kinetics of crystallization process of the supercooled liquid above the glass-transition temperature is also studied. This alloy shows a complex relaxation and crystallization processes which are discussed in the paper.
10.1016-j.intermet.2012.03.016	-1		Based on thermal stability investigations, a new parameter has been introduced in order to evaluate the formation tendency of different sized CuZr-based metastable alloys with the precipitation of B2 CuZr [26]. To verify our prediction further, a Cu46.25Zr44.25Al7.5Er2 alloy was prepared and its bulk metallic glass composites (BMGCs) with larger dimensions containing B2 CuZr precipitates were successfully fabricated by rapid quenching method. The composites exhibit macroscopically detectable compressive plastic strain and obvious work hardening, resulting from a deformation-induced martensitic transformation and the multiplication of shear bands. The plastic deformability of Cu46.25Zr44.25Al7.5Er2 BMGCs is relatively lower than that of Cu42.5Zr42.5Al5 BMGCs, most probably due to the intrinsic brittleness of Cu46.25Zr44.25Al7.5Er2 metastable alloys and/or the inhomogeneous distribution of B2 CuZr in the amorphous matrix.
10.1016-j.intermet.2012.03.028	-1		In this work, a new method to decrease the oxygen content in BMGs was proposed. Cu45Zr48Al7 bulk metallic glasses (BMGs) with two oxygen levels were prepared by adjusting the preparation process. The as-prepared Cu45Zr48Al7 BMG containing lower oxygen concentration exhibits larger plastic deformation than that containing higher level of oxygen. The fracture surface. was studied by SEM to reveal the fracture mechanism. The effect of oxygen on the local atomic structure of Cu45Zr48Al7 BMGs was studied by TEM. From the present work, the effects of oxygen on the structural and mechanical properties of Cu45Zr48Al7 BMGs were clearly revealed.
10.1016-j.intermet.2012.03.039	-1		A BMG/Cu composite rod and a plate with a Cu40Zr44Ag8Al8 BMG core and a pure copper sleeve have been fabricated by the coextrusion process. The interfaces between the two materials have been analyzed through various techniques including optical microscopy (OM), scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDX) and transmission electron microscopy (TEM). Good interface adhesion with metallurgical bonding has been formed, corresponding to two diffusion layers of about 100 nm near the Cu and BMG parts. An interface bonding model has been constructed based on these observations. The fracture mode of the BMG/Cu composite has been also characterized by compression tests, which involves debonding at the interface and plastic deformation of the Cu sleeve. (C) 2012 Elsevier Ltd. All rights reserved
10.1016-j.intermet.2012.03.057	-1		The behavior of Cu-Al-Be alloys under instrumented indentation using a Berkovich tip was studied. The pseudoelastic effect was evidenced in the transforming beta Cu-Al-Be phase as a closed hysteresis loop between the unloading-reloading paths in the P-h curves and high depth recovery ratios. From series of indentations conducted in the (beta + gamma 2) specimens, it was found that the indentation response of the two phases is remarkably different. Unlike the pseudoelastic beta phase, gamma(2) precipitates present an elastic-plastic behavior, obtaining a complete coincidence between the unload and reload path in the load-displacement curves, and a lower recovery capacity. An average contact pressure versus the penetration depth curve was estimated for each indentation curve, and results suggest that 8 GPa and 3 GPa can be considered an elastic limit for gamma(2) and beta phase respectively under Berkovich indenter stress state. The elastic modulus and the hardness of both phases were estimated from load-displacement curves using the Oliver and Pharr method.
10.1016-j.intermet.2012.07.011	-1		Rapid solidification of Cu46.4Ag38Sb15.6 alloy related with peri-eutectic transition was investigated in terms of microstructural evolution by means of glass fluxing and drop tube techniques. The microstructure formations of both bulk samples and alloy droplets are influenced by undercooling prior solidification, phase transition, cooling rate and volume fraction of the residual melt during different solidification stages. Two peri-eutectic transitions (L + (Cu) -> (Ag) + Cu3Sb and L + Cu3Sb -> (Ag) + Cu2Sb) are verified to be involved in the solidification of bulk samples. However, the second peri-eutectic transition is not reached in the solidification pathway of alloy droplets. The solidification product of peri-eutectic transition L + alpha -> beta + gamma generates in three manners: the formation of (beta + gamma) eutectic by the reaction between L and alpha phases, the direct growth of anomalous (alpha + beta + gamma) structure or (beta + gamma) eutectic from the melt.
10.1016-j.intermet.2013.07.022	13	clusters; atomic; glass; atoms; composition; dynamics; metallic; icosahedral; glasses; simulations; molecular; cu-zr; molecular dynamics; metallic glasses; structural	Cu-Zr Metallic glasses (MG) are considered to be composed of Icosahedral-like (ICO) clusters that may be distorted, truncated and/or interconnected. Aiming in gaining insight on the role of these units in the solidification-glass formation processes, as well as under mechanical solicitation, we performed detailed analysis of the electronic density of states, based on the Density Functional Theory, of the basic ICO-like clusters that were extracted from Cu65Zr35 equilibrium Molecular Dynamics (MD) configurations at various temperatures within the range from 2000 K to 300 K. In line with previous studies, we found that the d valence electrons of the Zr shell atoms occupy states close to the Fermi level, while s-s and d-s electronic hybridizations of the Cu-core/Cu-shell with the Cu shell atoms, respectively, occur at lower energy states and account for the deformation of the clusters, which is exclusively accomplished by these Cu-Cu distortions. Moreover, we found that upon quenching the mean atomic distances of the ICOs are decreasing due to shortening of the Cu-core/shell-Cu shell bonds, resulting in shifts of the corresponding states towards lower energies. Interestingly, it came out that the temperature dependence of these energies is linear, exhibiting slope changes at the melting and glass transition points. We applied the same analysis on ICOs extracted from Cu50Zr50 MD configurations under tensile solicitation from where we deduced the alterations that are caused in the electronic densities of states. These results could be of use for the understanding of the bonding characteristics of Cu-Zr model MGs and the mechanisms for the accommodation of the mechanical deformation.
10.1016-j.intermet.2013.10.018	4	transformation; martensite; martensitic; phase; shape; beta; memory; shape memory; temperature; temperatures; martensitic transformation; gamma; transformation temperatures; effect; thermal	In the present work the effect of Cu/Zr atomic ratio on structural and calorimetric properties of this high temperature shape memory alloy (HTSMA) is studied. It has been discussed the changes induced by Cu/Zr ratio on the martensitic transformation temperatures and the corresponding transformation heats coupled with the phases microstructure. The modification of the Cu content in the range +/- 2% at, around the equiatomic composition, does not drastically change the thermal properties of the alloys. Moreover, the Cu/Zr ratio strongly influences the microstructure in terms of the presence and amount of the other characteristic phases, Cu10Zr7 and CuZr2, in the place of the CuZr phase. The understanding of the basic properties of the binary system can be of great help for further investigations on CuZr based systems with other alloying elements. (C) 2013 Published by Elsevier Ltd.
10.1016-j.intermet.2015.06.004	-1		An amorphization process in (Cu49Zr45-xAl6+x)(100-y-z)NiyTiz (x = 1, y, z = 0; 5; 10) induced by ball-milling is reported in the present work. The aim was investigation of the effect of Ni and Ti addition to Cu49Zr45Al6 and Cu49Zr44Al7 based alloys as well as type of initial phases on the amorphization processes. Also the milling time sufficient for obtaining fully amorphous state was determined. The entire milling process lasted 25 h . Drastic structural changes were observed in each alloy after first 5 h of milling. In most cases, after 15 h of milling the powders had fully amorphous structure according to XRD except for those ones, where TEM revealed a few nanosized crystalline particles in the amorphous matrix. In (Cu49Zr45Al6)(80)Ni10Ti10 alloy the amorphization process took place after 12 h of milling and the amorphous state was stable up to 25 h of milling. In the case of (Cu49Zr44Al7)(80)Ni10Ti10 alloy the powders have fully amorphous structure between 12 h and 15 h of milling.
10.1016-j.intermet.2015.06.005	-1		Cu-45Zr-8Al and Cu-44.1Zr-7.8Al-2Y metallic glass ribbons were prepared by melt spinning and heat treated at two different temperatures followed by microstructural characterization by SEM and TEM. The compositions were selected to better understand the effect that oxygen has in the sequence and morphology of the phases formed during devitrification. A novel microstructure consisting of the Heusler Cu2ZrAl phase precipitated inside a B2-CuZr matrix that has shape memory properties was produced. It is proposed that this novel microstructure may be used to prepare samples with improved shape memory responses. The known cube cube relationship between the Heusler and B2 phases also provides direct evidence about the orientation relationship between the martensite and the parent B2 austenite and the results are in contrast to what is reported in the literature. The results also confirm that oxygen dissolved in these alloys leads to the formation of the B2 CuZr phase at lower temperatures than comparable low oxygen alloys.
10.1016-j.intermet.2015.09.002	11	glass; bulk; metallic; bulk metallic; gfa; bmg; glassy; metallic glass; ability; bulk metallic glass; amorphous; addition; crystallization; mm; glass-forming	The effects of Co alloying on mechanical properties of ternary Cu-Zr-Al bulk metallic glass (BMG) are systematically examined. Room temperature compression tests reveal enhanced fracture strain in ZrCuAlCo BMG materials upon appropriate amount of Co alloying. The microstructures of the composite materials investigated by X-ray diffraction and transmission electron microscopy reveal that the enhancement of fracture strain depends on the size and volume fraction of the B2 phase. The stress induced martensite transformation can only occur when the size of B2 grains is larger than a critical value, which enhances crack resistance within the vicinity of crack tip.
10.1016-j.intermet.2017.10.001	-1		The effects of vanadium element on the microstructure, mechanical properties and shape memory effect of Cu-13.0Al-4.0Ni-xV (x = 0.5, 1.0 and 2.0) (wt%) high-temperature shape memory alloy were investigated systematically. The results show that the Cu-13.0Al-4.0Ni-xV alloys display dual-phase morphology which consists primarily 18R martensite and (Al,Cu,Ni)V-3 phase. The grain size is significantly reduced by the addition of vanadium. The mechanical properties of Cu-13.0Al-4.0Ni-xV alloys are also improved due to the grain refinement and solid solution strengthening. When the pre-strain is 10%, the shape memory effect of 5.8% can be obtained for Cu-13.0Al-4.0Ni-0.5 V alloy.
10.1016-j.intermet.2019.106485	4	transformation; martensite; martensitic; phase; shape; beta; memory; shape memory; temperature; temperatures; martensitic transformation; gamma; transformation temperatures; effect; thermal	The influence of quenched-in vacancies on the elastic modulus and its dependence on the temperature was studied in a beta CuAlBe polycrystalline shape memory alloy. Samples with different quenching temperatures were submitted to different heat treatments and the behavior of the elastic modulus, phase transformation and microstructure with the temperature was carefully analyzed to understand the processes that occur in each stage. The quenched-in vacancies retained in beta phase migrate during a heating from room temperature up to 200 degrees C and the modulus exhibits a two stage behavior, associated with the higher mobility of the quenched-in vacancies at higher temperatures. However, those present in martensite phase would not be eliminated during the first heating or subsequent heating cycles at 200 degrees C or 300 degrees C. Part of these vacancies would also produce the hyperstabilization of some amount of martensite phase.
10.1016-j.intermet.2019.106577	-1		Cu-Ti intermetallic compounds are usually prepared by solid-solid Cu/Ti diffusion couples. However, we offer a rather unique approach to prepare Cu-Ti phases by simply mixing Cu and Ti powders and heating them at 1373 K. Typical CuTi2, CuTi and Cu4Ti3 phases are profusely formed. Intermetallic stoichiometry, morphology and the sequence of nucleation and growth between them are discussed in detail. Meanwhile, pertinent properties, such as hardness and fracture toughness are characterized. It is believed such technique may pave a way for faster production of Cu-Ti alloys with fine-tuned properties.
10.1016-j.intermet.2019.106655	7	irradiation; shear; grain; ta; deformation; size; radiation; voids; nanocrystalline; simulations; similar; void; temperature; irradiated; boundaries	Ion irradiation and annealing experiments were performed on Cu60Zr20Hf10Ti10 bulk metallic glass (BMG) specimens to investigate their irradiation- and temperature-induced microstructural and mechanical property evolution. For the ion irradiations, samples were exposed to 9 MeV Ni3+ ions to a midrange (similar to 1.2 mu m depth) dose of 10 displacements per atom (dpa) at temperatures ranging from room temperature to 360 degrees C (the corresponding peak dose at similar to 2.8 mu m depth was similar to 25 dpa). Bulk X-ray diffraction (XRD) and transmission electron microscopy (TEM) characterization revealed that the alloy did not crystallize during irradiation up to 290 degrees C but did partially crystallize at 360 degrees C. XRD analysis revealed that the crystallization which occurred in the sample irradiated at 360 degrees C was caused by thermal effects instead of irradiation displacement damage. Subsequent Rietveld refinement analysis of the XRD measurements revealed the presence of two distinct crystal phases, namely a CuTiZr hexagonal structure belonging to the P6(3)/mmc space group and a CuTi tetragonal structure belonging to the P4/mmm space group. Nanoindentation experiments revealed that no pronounced hardness changes occurred in the specimens irradiated at room temperature and 290 degrees C, although significant hardening was observed in the sample irradiated at 360 degrees C. The significant increase in the hardness at 360 degrees C was ascribed to thermally induced partial crystallization of the alloy instead of the ion irradiation. In general, the results of the nanoindentation experiments and XRD characterization suggest that although the Cu BMG exhibits good stability during irradiation at temperatures up to 290 degrees C it is not suitable for irradiation environments where the temperature is 360 degrees C for extended periods of time. The Lam and Chong extrapolation method, which has been used to study the indentation size effect (ISE) in amorphous alloys, was employed to quantify how irradiation and temperature affect this type of behavior in the BMG. However, the poor linear fitting of the indentation hardness data by this model indicate that a new ISE model is likely needed to quantify indentation hardening in BMGs.
10.1016-j.intermet.2020.106749	-1		gamma' phase (AlNi3) particles' precipitation behavior in the Cu-15Ni-xAl alloys (wt%, x = 0, 1, 2, 3 and 4) ageing at different temperature was systematically discussed with the help of Calphad method. With fixed ageing temperature, when Al content increases from 1 wt% to 4 wt%, the gamma' phase particles transform from a few microns to dozens of nanometers in size. The increasing Al content was proven to raise the instability of single phase solid solution (FCC), which can be expressed by the increasing value of G(excess)(FCC) and will result in the increasing critical temperature for precipitation. Supersaturation at fixed ageing temperature is thus raised with increasing Al content, so does the nucleation driving force of gamma' phase. Simultaneously, the precipitation strengthening in Cu-15Ni-4Al firstly increases and then decrease with ageing temperature decreasing from 700 degrees C to 400 degrees C, which is due to the competition between increasing nucleation driving force and decreasing self-diffusion coefficient of element with decreasing temperature. The continuous and discontinuous precipitation behaviors of gamma' phase were also discussed, which will be respectively promoted and suppressed with decreasing ageing temperature due to the relatively high nucleation driving force. However, both continuous and discontinuous precipitation will be suppressed when the ageing temperature decreases to 400 degrees C due to the too low self-diffusion coefficient.
10.1016-j.intermet.2020.106894	-1		In order to solve the segregation and discontinuous precipitation of Cu-Ni-Sn alloys and explore the influence mechanism of solid soluble microelements on the microstructure and properties. Herein, based on the cluster-plus-glue-atom model, Zn or Co, with different solubilities in Cu, was selected as the fourth element in the way of replacing a small portion of Sn for the composition design of Cu-Ni-Sn-Zn (Co) series alloys. The solid solution forms and positions of Zn and Co solutes were revealed according to EPMA composition analysis and variation of the lattice parameter of the Cu matrix in solution treated alloys, and form atomic site occupation point of view, the influence of Zn or Co on solidus-liquidus temperature range were discussed. Furthermore, phase transformation and resistivity thermal stability with temperature rising were investigated and discussed utilizing results of variable temperature resistance. These results show that Zn solutes dissolve in the form of clusters, resulting in a strong solid solution strengthening, existing less effect on conductivity, and increasing comprehensive properties after long-term aging, which indicates that Zn can be a good candidate for the multi-component design of Cu-Ni-Sn alloys. These findings may offer new insights on composition optimization of Cu-Ni-Sn alloy.
10.1016-j.intermet.2020.107023	13	clusters; atomic; glass; atoms; composition; dynamics; metallic; icosahedral; glasses; simulations; molecular; cu-zr; molecular dynamics; metallic glasses; structural	The local environment of Cu47.5Zr47.5M5 (M = Ag and Al) metallic liquids and glasses has been studied in detail using the embedded atom method combined with molecular dynamics simulations. The effects of the addition of Al and Ag separately to CuZr-based alloys on the microstructure have been comprehensively discussed in terms of structural functions, bond angle distributions, coordination numbers and common neighbor analysis. The simulated structure factors and coordination numbers are in good agreement with the experimental results the literature. According to different analysis results, it has been observed that Ag prefers Zr to Cu and Al prefers Cu to Zr as the neighboring atom. Our results show that Al is much more effective than Ag in the development of the icosahedral short range order, although the short range order of both glass-forming liquids and glasses shows a strong dependence on Ag and Al additions. In addition, the atomic radii of Ag and Al atoms are very close to each other, but results have shown that Ag atoms (12 = CN <= 15) tend to form interestingly larger clusters than Al atoms (12 = CN <= 14).
10.1016-j.intermet.2021.107162	8	hot; deformation; strain; strain rate; dynamic; hot deformation; recrystallization; dynamic recrystallization; flow; rate; flow stress; compression; constitutive; degrees; stress	The elongation of high-strength copper alloy with tensile strength over 1300 MPa is generally less than 3%. In this paper, a novel Cu?20Ni?20Mn-0.3Nb-0.3Cr-0.1Zr(wt%) alloy was prepared, of which the tensile strength, elastic modulus and elongation is 1445 MPa, 147 GPa and 6.8%, respectively. The flow stress strain and microstructure evolution during high temperature deformation at different strain temperatures and strain rates are studied to obtain the high temperature deformation law and dynamic recrystallization mechanism of the alloy. The research shows that the flow stress of the design alloy increases rapidly with the increase of the strain during the initial stage of thermal deformation. When the strain rate is higher and the strain temperature is lower, the peak value of flow stress is larger. The thermal activation energy of the designed alloy is 353.31 kJ/ mol. When the strain temperature is 650?C?720 ?C and the strain rate is 0.1s-1-5s-1, the alloy is in the hot deformation instability zone. The optimal deformation temperature of the alloy is 750?C?850 ?C. When the deformation temperature reaches 800 ?C, dynamic recrystallization occurs in the alloy structure. When the design alloy is deformed at a temperature of 850 ?C, the recrystallization power of the alloy is mainly the deformation stress energy, and the degree of recrystallization mainly depends on the strain rate. At this time, the faster the strain rate is, the more obvious the recrystallization effect is, and even the recrystallization grain growth will occur.
10.1016-j.intermet.2021.107286	-1		The crystal structure of martensite in Cu-27at%Zn-9.0 at%Al alloy has been studied by using spherical-aberration-corrected high-angle annular dark-field scanning transmission electron microscopy (HAADF-STEM) and geometrical phase analysis GPA) to examine possible changes in atomic rearrangements during martensitic transformation of this ternary system. Observation along [100](M) zone axis is suitable for examining a chemical order of the martensite, and showed that, despite the non-stoichiometry of the alloy, atomic columns containing Al atoms are imaged and distinguished from the others. On the other hand, observation along [010](M) zone axis directly revealed that the parent and martensitic phases possess L2(1) and 18R (2 (1) over bar) structures, respectively. These observations suggested that the martensite retained the local chemical order of the parent phase without shuffling before and after the transformation. GPA revealed that the interface between the two phases was coherent with tilting of the basal plane approximately 6 degrees across the boundary, which makes otherwise large inclination small during the martensitic transformation.
10.1016-j.intermet.2021.107315	1	shape; memory; shape memory; damping; martensite; martensitic; damping capacity; transformation; capacity; strain; superelasticity; temperature; cu-al-mn; shape memory effect; effect	Grains of a Cu-Al-Ni-Mn-Ti shape memory alloy (SMA) were remarkably refined by the Al-La-B inoculant. Evolution of microstructures and changes of both martensitic transformation (MT) temperatures and damping property of the Cu-Al-Ni-Mn-Ti SMA were also systematically investigated. It was found that with increasing the adding amount of inoculant, the grain size decreased first and then increased, whereas the damping increased first and then decreased. When the adding amount of inoculant reached 2.5 wt%, the smallest grains and the highest damping could be obtained. The improvement of damping could be attributed to the increased density of interfaces between matensite lamellae and between twins. Moreover, with increasing the adding amount of inoculant, all characteristic temperatures of both reverse and forward MT shift to high temperature side. This could be ascribed to the decreased Al content in the Cu-Al-Ni-Mn-Ti SMA due to the formation of Al11La3 phase. In addition, this is also related to the changes of the density of grain boundaries and the order degree of the Cu-Al-Ni-Mn-Ti SMA.
10.1016-j.intermet.2022.107493	13	clusters; atomic; glass; atoms; composition; dynamics; metallic; icosahedral; glasses; simulations; molecular; cu-zr; molecular dynamics; metallic glasses; structural	During the rapid cooling process, the atomic structure of the Cu60Ti20Zr20 ternary alloy under external pressure was investigated by molecular dynamics simulations using the embedded atom method potential. The effect of the pressure was discussed in detail by using a variety of analysis methods. Glass transition temperature determined by the modified Wendt-Abraham parameter was found to increase with increasing pressure. It was observed that the calculated total (or partial) pair distribution function and structure factor are in good agreement with the experimental x-ray data (with the ab-initio molecular dynamics results). The bond angle distributions of Cu-centered triplets were more consistent with ideal icosahedral clusters than that of Ti- and Zrcentered triplets. The dominant clusters for all pressures were icosahedral-like clusters that were not much affected by pressure. In addition to the bonds between Cu-Zr pairs shortening more easily under high pressure than other pairs, it is found that the Cu60Ti20Zr20 glassy alloy remained stable under pressure and its topological and atomic structures did not change much with pressure.
10.1016-j.intermet.2022.107497	-1		Cu-9Ni-6Sn specimens with different Nb contents ranging from 0 to 0.22 wt% were prepared by a vacuum induction furnace, and needle-like NbNi3 particles were found at the grain boundaries and interior after solution treatment. The results indicated that these NbNi3 particles suppressed the discontinuous precipitation (DP) growth during aging treatment. By using Johnson-Mehl-Avrami-Kolmogorov (JMAK) equation and Arrhenius equation, the kinetics of DP is also figured out and the activation energy (Q) of the DP in Cu-9Ni-6Sn-xNb (x = 0, 0.05, 0.22 wt%) alloys are 75.8 kJ/mol, 80.9 kJ/mol and 88.5 kJ/mol, respectively, indicating that the atom diffusion for producing DP is more difficult in Nb-bearing alloys, and the formation of DP is inhibited correspondingly. What's more, the lamellar spacing (S) of DP increased and the growth rate of DP decreased in the with the Nb-bearing Cu-9Ni-6Sn alloy.
10.1016-j.intermet.2022.107570	-1		In the rapidly developing modern industrial fields, the materials used are often required to have simultaneously high strength and high electrical conductivity. However, these two properties often conflict and cannot be met at the same time. In the present study, we developed the Cu/Cu-Zr-Al bulk metallic glass (BMG) composites which exhibited simultaneously high strength and high electrical conductivity, as well as large plasticity. The BMG composites were fabricated by using spark plasma sintering crystalline Cu-coated Cu-Zr-Al metallic glass composite powders. The effect of particle size of the Cu-Zr-Al metallic glass powders on mechanical properties and electrical properties of the BMG composites was investigated systematically. Microstructure of contact in-terfaces between crystalline Cu and Cu-Zr-Al metallic glass was also characterized and discussed. This study is expected to provide an effective technical approach for the development of new high strength and high con-ductivity materials.
10.1016-j.intermet.2023.107826	1	shape; memory; shape memory; damping; martensite; martensitic; damping capacity; transformation; capacity; strain; superelasticity; temperature; cu-al-mn; shape memory effect; effect	In this study, the Cu-Al-Ni based shape memory austenite single crystal (Cu-13.5Al-4Ni-6Fe-4Mn) with two different orientations were prepared for the first time through simply annealing cast alloy. The single crystal contains the L21 matrix and rich-Fe nanoprecipitates with two structures (D03 and A2). The martensitic trans-formation temperatures and chemical compositions of two different-oriented single crystals are very close. Two different-oriented single crystals both possess complete superelasticity when deforming from 3% to 8%. The critical stress of stress-induced martensite for the [2-75] single crystal is about 500 MPa, which is more than twice that of the [-401] single crystal. The [-401] single crystal has much better cycle stability, in which it can maintain stable and prefect superelasticity during 500 cycles without fracture.
10.1016-j.intermet.2023.107853	-1		Here, we report primary and secondary nanoscale phase separation in Cu46Zr46Al8 (at%) bulk metallic glass (BMG) achieved by altering the casting temperature. The BMG rods were cast by using the melting currents of 160 A and 220 A which provide, respectively, higher and lower cooling rates. The transmission electron microscopy and energy-dispersive X-ray analysis revealed that the higher cooling rate conditions brings a primary phase separation of nanoscale Cu-rich amorphous regions which are evenly dispersed in the Cu-depleted amorphous matrix phase. However, lower cooling rates results in a bimodal microstructure comprising coarsened primary-separated nanograins and very fine secondary-separated nanograins throughout the amorphous matrix containing nanocrystals of smaller than 5 nm in size. This unique microstructure developed under lower cooling rates gives lower relaxation enthalpy, higher short-range ordering, and enhanced strain-hardening. Our study emphasizes the significant role of casting temperature on controlling the morphology of nanoscale phase separation in BMGs.
10.1016-j.intermet.2023.107906	11	glass; bulk; metallic; bulk metallic; gfa; bmg; glassy; metallic glass; ability; bulk metallic glass; amorphous; addition; crystallization; mm; glass-forming	The effect of yttrium (Y) on the glass-forming ability (GFA), mechanical properties and corrosion of (Cu50Z-r43Al7)100-xYx (x = 0, 2 and 4, in at. %) alloys was investigated. The GFA of Cu50Zr43Al7 alloy was improved by the addition of Y, with a GFA of 15 mm in diameter being obtained for (Cu50Zr43Al7)98Y2. In uniaxial compression, the bulk metallic glasses (BMGs) exhibited a limited plastic strain of less than 1%, however compressive fracture strength and Young's modulus of 1787-2006 MPa and 101-122 GPa were achieved, respectively. Fracture surfaces and shear bands were studied via scanning electron microscopy. The corrosion behavior of BMGs was analyzed by potentiodynamic polarization experiments and electrochemical impedance spectroscopy (EIS) in acidic chloride (1 M HCl) and neutral chloride (0.6 M NaCl) environments. As a result of the Y addition, the corrosion resistance of the base BMG was improved.
10.1016-j.intermet.2023.107960	-1		High-entropy alloys are a class of materials intensely studied in the last years due to their innovative properties. Their unconventional compositions and chemical structures hold promise for achieving unprecedented combinations of mechanical properties. The Cu-Fe-Ni-Mo-W multicomponent alloy was studied using a combination of simulation and experimental production to test the possibility of formation of a simple solid solution. Therefore, Molecular Dynamics and hybrid Molecular Dynamic/Monte Carlo simulations from 10K up to the melting point of the alloy were analyzed together with the experimental production by arc furnace and powder milling. The Molecular Dynamics simulations starting with a bcc type-structure show the formation of a singlephase bcc solid solution type-structure, whereas using Monte Carlo one, generally produced a two-phase mixture. Moreover, the lowest potential energy was obtained when starting from a fcc type-structure and using Monte Carlo simulation giving rise to the formation of a bcc Fe-Mo-W phase and a Cu-Ni fcc type-structure. Dendritic and interdendritic phases were observed in the sample produced by arc furnace while the milled powder evidence an separation of two phases Cu-Fe-Ni phase and W-Mo type-structures. Samples produced by both methods show the formation of bcc and a fcc type-structures. Therefore, the Monte Carlo simulation seems to be closer with the experimental results, which points to a two-phase mixture formation for the Cu-Fe-Ni-Mo-W multicomponent system.
10.1016-j.intermet.2023.107975	-1		Equiatomic Al-Ni-Co-Cu-Zr alloy was produced by arc melting. Rapidly quenched rods were prepared by suction casting method. Density, electrical resistivity and thermal analysis of the alloy were investigated experimentally. Basing on X-ray diffraction it was shown that the structure of the alloy consists of two competing solid solutions: BCC-ZrNi2Al (Heusler-type phase) and & gamma;-phase Cu9Al4. In addition, pure cooper and Cu3Al, Cu5Zr7Ni5 intermetallic compounds were determined. Rapid quenching of this alloy leads to the formation of solid solutions based on BCC-ZrNi2Al and high-temperature Cu3Al phase. It is shown that the alloy in crystalline state has a linear density change up to solidus temperature. A region of resistivity decrease with increasing temperature is found out for the first time. The melting process goes in a wide temperature range (above 250 K) where 4 thermal reactions were detected. Density and electrical resistivity changes here non-linearly. In liquid state there are no thermal effects in the alloy and temperature dependencies of density and electrical resistivity can be fitted by linear functions.
10.1016-j.intermet.2023.107977	-1		The Cu20Ni20Mn alloy possesses both high strength and excellent elastic modulus, which has the potential to work in some extreme environments. In our study, by adding Ga into the Cu-Ni-Mn alloy, a new kind of Cu20Ni20Mn-xGa (x = 0, 1, 5 wt%) alloys were produced. After undergoing different thermal-mechanical treatments, these alloys were comprehensively investigated particularly for their mechanical properties and microstructures. While at the peak aging condition, the ultimate tensile strength and total elongation of the Cu20Ni20Mn-1Ga alloy are 1476 MPa and 7.9% respectively, both are higher than that of the Ga-free case (1391 MPa and 3.9%). The Ga added in small amount facilitates the nucleation of NiMn nanoprecipitates inside the grain instead of on the grain boundary, which provides enormous precipitation strengthening and greatly enhances the alloy. However, with addition of excessive Ga (e. g. 5 wt%), discontinuous Ni2MnGa precipitates are observed at grain boundaries, which greatly reduce the ductility of the alloy. Based on our research, we believe that adding appropriate amount of Ga is beneficial for the mechanical properties of the Cu-Ni-Mn alloys, which will become a potential strengthening method for Cu alloys in the future.
10.1016-j.intermet.2023.108005	-1		The second-phase particles play a critical role in refining microstructure and promoting properties in ultra-high strength Cu-Ti alloys. In this study, we researched the effect of adding 0-0.3 wt% vanadium (V) element on the Laves phase of Fe2Ti and the resulting variation of microstructures and properties in Cu-3.2Ti-0.2Fe alloys using first-principle calculations, in-situ transmission electron microscopy (TEM) and mechanical tests. The firstprinciple calculation results showed that the combination energy and formation enthalpy of Laves phase were affected by the V element, with the (Fe4,V4)Ti4 having the most stable structure and the lowest combination energy of -529.14 kJ mol- 1.atom- 1. Furthermore, the face-centered-cubic (FCC) or amorphous crystal structured boundary layer of Laves phase was coherent with the Cu-matrix when 0.2 wt% V was added to the alloys, acting as a more effective refiner of heterogeneous nucleation during the casting process. In-situ heated TEM evidenced that the Laves phase acted as an inhibitor of dislocation motion and grain boundary migration during the annealing process after cold-deformation. After annealing at 800 degrees C for 3 min and aging at 400 degrees C for 2 h and then at 450 degrees C for 4 h, Cu-3.2Ti-0.2Fe-0.2 V alloy possessed the ultimate tensile strength of 976.8 MPa and elongation of 18.8%, exhibiting high strength and good ductility.
10.1016-j.intermet.2023.108021	1	shape; memory; shape memory; damping; martensite; martensitic; damping capacity; transformation; capacity; strain; superelasticity; temperature; cu-al-mn; shape memory effect; effect	With the aim of property enhancement, the grains in a Cu-Al-Ni shape memory alloy (SMA) were successfully refined by adding Al-La-B inoculant. In order to further optimize the microstructure, the inoculated Cu-Al-Ni SMA was then subjected to caliber rolling. It was found that the grains were further significantly refined after caliber rolling, but there was & alpha; phase precipitation. After quenching treatment, the & alpha; phase disappeared, whereas the grain size slightly increased. The changes of properties with the increase of rolling reduction were investigated. It was found that the tensile strength increased, whereas the elongation increased first and then decreased. After quenching treatment, the tensile strength and elongation increased monotonously. The internal friction (IF) peak arising from the reverse martensitic transformation (MT) decreased, and the peak position shifted towards the high temperature side. After quenching treatment, the IF peak increased monotonously, whereas the peak position remained nearly unchanged. Correlated mechanisms were discussed.
10.1016-j.intermet.2023.108062	14	strength; properties; conductivity; electrical; mechanical; cu-; grain; mpa; electrical conductivity; aging; precipitation; phase; mechanical properties; tensile; phases	This study showcases the preparation of Cu50Zr43Al7 metallic glass-reinforced ultrafine grain copper matrix composites using a powder metallurgical process to achieve a superior combination of strength and electrical conductivity. The mechanical ball milling (BM) process is utilized to effectively refine the Cu matrix grains to the nanoscale. Furthermore, high-pressure spark plasma sintering (SPS) is employed to prevent grain growth and improve the interface bonding between two phases. Increasing the Cu50Zr43Al7 addition content improved the mechanical properties under a load transfer strengthening strategy. Notably, the 20 wt% Cu50Zr43Al7/Cu composite demonstrates excellent mechanical properties and high electrical conductivity. This is attributed to the uniformly-dispersed Cu50Zr43Al7 metallic glass particles in the ultrafine grain Cu matrix with well-established interfacial bonding. The synergistic strengthening of the Cu50Zr43Al7/Cu composites represents a novel choice for switch contact materials application, maintaining excellent mechanical properties while satisfying conductive requirements.
10.1016-j.intermet.2023.108176	-1		Due to the technical requirements of preparing Nb3Sn superconducting wires using the bronze method, the Cu-Sn-Ti alloy with high Sn content and matching mechanical properties with pure Nb as the substrate is the key to the smooth preparation of superconducting wires. However, the high content of Sn leads to the generation of a large number of intermetallic compounds (IMCs) in Cu-Sn-Ti alloy are the main reasons for the deterioration of the elongation and strength of Cu-Sn-Ti alloy. This work uses unidirectional solidification (US) and homogenization annealing (HA) methods to regulate the volume fraction and types of IMCs in Cu-15Sn-0.3Ti alloy. The volume fraction of IMCs decreases from 20.6 % to 0.1 % after HA, and the network delta phases (Cu41Sn11) transform to fine gamma phase (Cu3Sn) and CuSn3Ti5. The ultimate tensile strength (UTS) and elongation of the samples treated with HA increase by 2000 % and 94 %, respectively, and deformation twins are found in the stretched samples. The research results indicate that the elongation and UTS of Cu-15Sn-0.3Ti alloy are improved by the decrease of IMCs volume fraction and deformation twins formed during the tensile process.
10.1016-j.intermet.2024.108196	-1		A novel self-lubricating Cu-12Sn-xBi-2Ni alloy was developed and the effect of Bi on microstructure and properties of Cu-12Sn-xBi-2Ni was investigated. The formation reason of the solidification microstructure was analyzed by CALPHAD method and verified by water quenching experiment. The mechanical properties and the friction properties of alloys were tested by the pin-on-disc wear tester and electronic universal material tester. The tensile property deteriorates with the increase in Bi content, while the Brinell hardness and anti-friction properties of the alloy are enhanced, and Cu-12Sn-6Bi-2Ni alloy is identified to be the alloy with the best self-lubricating property. The addition of Bi increases the number of Sn-rich phase and changes the morphology of Sn-rich phase, resulting in fine Bi-rich phase and lamellar microstructure precipitate around the Sn-rich phase. Liquid Bi as nucleating particles promotes the precipitation of delta phase, resulting in the formation of lamellar delta phase and the Sn-poor alpha-Cu phase.
10.1016-j.intermet.2024.108390	15	aging; strength; conductivity; electrical conductivity; electrical; mpa; treatment; strengthening; degrees; cu-; cold; precipitation; tensile strength; tensile; iacs	A novel Cu-2.5Fe-0.2Si-0.3Mg-0.3Cr-0.1Zr-0.2Y (wt%) alloy is designed, which exhibits nice comprehensive properties under multi-stage thermo-mechanical processing, with a conductivity of 57.11 %IACS and a tensile strength of 672 MPa. The main secondary phases in the alloy include micron-scale FeCrSi and CuZrY phases, as well as nanoscale precipitate of FeCrSi. Conductivity and strength of the alloy are mainly improved by the precipitation of nanoscale FeCrSi phases, which increases dislocation obstruction and matrix purity. The (220) plane of the precipitate exhibits a 9.5 degrees misfit angle with the (020) plane of the matrix under the [112] FeCrSi zone axis. The formation of low angle grain boundaries (LAGBs) results in significant grain refinement effects. The average grain diameter of the alloy is about 1.58 mu m, which is related to the piles-up of dislocations along the boundaries and the different deformability between the micron-scale second phase and the matrix.
10.1016-j.intermet.2025.108747	17	wear; composites; coating; friction; composite; coatings; surface; tribological; properties; wear resistance; resistance; powder; sliding; matrix; wear rate	3Cr13 stainless steel (SS), commonly applied to marine engineering components such as bearings and drive shafts, is damaged by tribocorrosion. For improving the resistance of tribocorrosion, the Cu55Zr25Ti15Ni5 glassy composite coating is prepared via high-velocity air-fuel (HVAF) spraying technology on 3Cr13 SS, and the tribocorrosion experiment of the coating is investigated using friction and wear tester. The coating exhibits a multiphase structure, comprising amorphous-nanocrystalline region and oxide phase consisting of TiO2 and tZrO2, of which the amorphous-nanocrystalline phase accounts for about 53 %. The nanomechanical properties and the corrosion properties are investigated. The analysis of the tribocorrosion system (counter-balls, posttribocorrosion solution, and wear tracks) is carried out using 3D scanner, inductively coupled plasma mass spectrometer (ICP-MS) and scanning electron microscope (SEM). Abrasive wear and fatigue wear mainly occur in the coating during tribocorrosion, and adhesive wear and chemical reaction wear are slight. As the load increases, tribo-film is formed on the surface of the coating and the wear rate decreases dramatically, due to the suppression of abrasive wear. The wear rate of the coating is only half of that of 3Cr13 SS at the load of 30N.
10.1016-j.intermet.2025.108762	-1		Copper alloys are widely used in the electrical and electronic devices due to their excellent electrical and thermal conductivity. However, the trade-off relationship between strength and conductivity limits their application in the electrical contacts and circuit leads. In this study, an experimental strategy based on melt extraction and appropriate post-heat treatment was proposed to design one kind of B2-phase ordered Cu-Pd-Ag-Ru microfiber. It was found that this microfiber displays the excellent comprehensive performance of the strength and the conductivity. In comparison with the cast alloy, the strength for the designed microfiber is increased by 2.75 times and there appears the 70 % enhancement for the electrical conductivity. The strengthening mechanisms can be attributed to the phase transition from FCC to B2 phase, grain refinement, and the formation of Ru and Ag precipitates. Furthermore, the significant improvement in electrical conductivity is primarily due to the introduction of the B2 ordered phase and the elongation of longitudinal grains. The current study not only provides one kind of excellent copper alloys for the electrical contacts and circuit leads, but also offers a new strategy for surmounting the strength-conductivity trade-off in metals.
10.1016-j.intermet.2025.108913	14	strength; properties; conductivity; electrical; mechanical; cu-; grain; mpa; electrical conductivity; aging; precipitation; phase; mechanical properties; tensile; phases	This study investigates the role of silicon in the formation and evolution of heterogeneous intermetallic compound phases in Cu-Ni-Si(-Mn) alloys subjected to homogenization treatment at 980 degrees C. Si plays a critical role in both the intragranular and grain boundary precipitation behavior. An increase in Si content significantly enhances the volume fraction and size of intragranular delta-Ni2Si precipitates. Furthermore, it promotes morphological changes at the grain boundaries, increasing the aspect ratio of boundary precipitates and transforming them into thin, film-like G-phase structures (Mn6Ni16Si7) in Mn-containing alloys. While the overall volume fraction of grain boundary phases remains relatively stable, these Si-induced morphological changes alter the grain boundary characteristics and impact mechanical performance. In Mn-free Cu-Ni-Si alloys, higher Si content leads to the coarsening of grain boundary delta-Ni2Si precipitates, degrading both strength and ductility. In contrast, in Mn-containing alloys, the grain boundary G-phase remains stable without coarsening, even with increased Si content, which helps retain ductility (similar to 10 %) and enhances overall mechanical properties. These findings highlight Si as a key element in tailoring microstructures and optimizing the mechanical performance of Cu-Ni-Si(-Mn) alloys through control of intermetallic phase formation.
10.1016-j.intermet.2025.108937	12	thermodynamic; ternary; phase; data; experimental; equilibria; phase equilibria; liquid; binary; experimental data; calculated; phases; literature; model; calphad	The phase equilibria of the Cu-Zr-V system at 900, 800, 700 and 600 degrees C were determined by X-ray diffraction (XRD) and scanning electron microscope (SEM) with energy dispersive X-ray spectrometry (EDS). The solubilities of third element in the binary phase i.e., V2Zr, Cu5Zr, Cu51Zr14, Cu10Zr7, Cu8Zr3, CuZr and CuZr2, were determined. Two ternary compounds, CuZrV and CuZr6V3, were identified, with the CuZr6V3 phase being newly discovered. Compositional analyses revealed the CuZrV phase as Cu28.8Zr39.8V31.4at 900 degrees C and Cu33.5Zr37.3V29.2 at 800 degrees C, while the CuZr6V3 phase exhibited compositions of Cu9.0Zr57.8V33.2 at 900 degrees C and Cu5.9Zr57.4V36.7 at 700 degrees C. A thermodynamic assessment of the Cu-Zr-V system was performed using the CALPHAD (CALculation of PHAse Diagrams) approach, employing substitutional solution models for solution phases and sublattice models for intermetallic compounds. The ternary compounds CuZrV and CuZr6V3 were described as (Cu)1(Zr)1(V)1 and (Cu)1(Zr)6(V)3, respectively. A set of self-consistent thermodynamic parameters of the Cu-Zr-V system was obtained. The isothermal sections at 900, 800, 700 and 600 degrees C and liquidus projection were calculated, and the reaction scheme was constructed. The calculated phase equilibria show good agreement with experimental observations.
10.1016-j.intermet.2025.108978	-1		The origin of the abrupt dynamic slowdown observed during the concealed liquid-solid transition at temperature T-ls in rapidly cooled Cu-Zr metallic liquids remains poorly understood. Here, we resolve this longstanding puzzle by combining molecular dynamics simulations with the largest standard cluster analysis (LaSCA) to establish a direct causal link between topological cluster percolation and relaxation dynamics. Our findings reveal that topologically close-packed (TCP) clusters with an average size (S-TCP) exceeding a critical threshold (>3) trigger a dynamic arrest below T-ls. This arrest arises from cooperative atomic motions driven by the spatial percolation of TCP clusters, which dominate the structural evolution. The identified S-TCP threshold (3.0-4.0 across compositions) serves as a universal signature of rigidity onset in metallic glass-forming liquids. By bridging atomic-scale topological connectivity with macroscopic dynamics, this work provides a predictive framework for tailoring relaxation behavior in non-equilibrium alloys.
10.1016-j.istruc.2023.06.094	-1		Knowledge of mechanical properties and hardness is essential for the cost-effective and efficient friction stir welding (FSW) in producing Cu and Al composites. Correct process management requires knowledge of consistent model predictions. Many factors affect the mechanical properties and hardness, which include pin geometry, forward speed, rotational speed, and pin angle. The purpose of this research is to investigate the use of Relevance Vector Machine (RVM), Support Vector Machine (SVM), and Least Square Support Vector Machine (LSSVM) algorithms in hybrid modeling of the mechanical properties and hardness in FSW. Then, the resulting mechanical properties are modeled to three modeling methods: the hybrid LSSVM-RVM, hybrid SVM-RVM, and hybrid SVM-LSSVM. A comparison between the experimental data and the output of these models were made. R2, RMSE, and RMSE/ymax statistical indices was used in this research . The values of R2 for the results of the tensile test and hardness area were obtained as 0.9712 and 0.9126, respectively. The results showed that the hybrid LSSVM-RVM model could efficiently estimate the mechanical and hardness properties.
10.1016-j.istruc.2025.108516	-1		To address the issue of significant residual deformation in conventional concrete-filled steel tube (CFST) columns subjected to seismic loading, this study proposes two configurations of self-centering shape memory alloy (SMA) tubular concrete columns: single-tube and double-tube systems. In these configurations, traditional steel tubes are replaced with cost-effective Cu-Al-Mn SMA materials. Thermal treatment and cyclic tensile tests were conducted on Cu-Al-Mn SMA plates. Based on the experimental results, the constitutive model parameters for the finite element analysis of Cu-Al-Mn SMA plates were determined. Following the validation of the finite element model's accuracy against existing experimental data on CFST columns, a parametric finite element analysis was performed to assess the seismic performance of the single-tube and double-tube self-centering concrete columns. The experimental results indicate that both the single-tube and double-tube self-centering columns exhibit enhanced self-centering capabilities, leading to a significant reduction in residual deformation. Additionally, comparative analysis among five distinct column configurations demonstrates that the three self-centering variants achieve markedly lower residual deformation. Data availability: All data, models, or code that support the findings of this study are available from the corresponding author upon reasonable request.
10.1016-j.jallcom.2003.10.019	-1		The present work concerns study of the precipitation sequence due to aging below the critical aging temperature of cold-worked powder samples of industrially important Cu-Ni-Sn alloys with compositions, Cu-15 wt% Ni-(5, 8, 13) wt% Sn. The analysis adopts a recently developed JAVA based software Materials Analysis Using Diffraction (MAUD), based on Rietveld's whole X-ray pattern fitting methodology. The evoluted phases have been characterized microstructurally in terms of different defect parameters, namely, stacking, twin and compound fault probabilities, crystallite (domain) sizes, microstrains (root mean square, rms strains), dislocation densities, preferred orientation parameters, etc. The analysis also includes quantitative estimation of phase abundances of the precipitating phases. The decomposition due to aging with varying Sri composition and aging period has been critically studied and the percentage of volume fraction of the evoluted phases has been evaluated and compared. The results depict, for the three different alloy compositions, three distinct different types of precipitation sequence comprising alpha, gamma and delta phases with continuously varying volume fractions with aging time. The size-strain-shape analysis adopting the Popa model reveals almost isotropic values of both the crystallite sizes and rms strains in all [hkl] directions for the evoluted phases. The values of all the above defect parameters have been evaluated and compared for elucidating a better structure-property relationship.
10.1016-j.jallcom.2004.06.077	-1		Mechanical properties were detected by the nanoindentation method for the Cu-Ta amorphous films with Ta content from 25.6 to 96 at%. The hardness and elastic modulus are found to vary linearly with the Ta concentration. The incremental change of the elastic modulus is 1.35 GPa per Ta atom and that of the hardness is 0.205 GPa per Ta atom. The samples with Ta content higher than 71 at% have higher elastic moduli than the crystalline counterparts of the mechanical mixture. This is similar to the supermodulus effect observed in the multilayers in many immiscible binary alloy systems. A model based on the inter-atomic potential is proposed to explain the enhanced modulus and relate it to the additional Gibbs free energy stored in the alloy after amorphization. (C) 2004 Published by Elsevier B.V.
10.1016-j.jallcom.2004.07.013	-1		Thermo-mechanical treatment was employed in this study to optimize the strength and conductivity of Cu-Fe-Ag microcomposites. The strength/conductivity properties of Cu-Fe-Ag microcomposites drawn to eta = 4.8 without intermediate heat treatments (NH) were observed to be 1006 MPa/39% IACS and those drawn to eta = 6.3 with three intermediate heat treatments (IH-3) were 939 MPa/56.2% IACS. A substantial increase of conductivity was obtained at the expense of a modest loss of the strength by the employment of intermediate heat treatments. The precipitation of impurities and alloying elements during intermediate heat treatment is thought to increase the conductivity due to the reduced impurity scattering. The activation volume was measured to be 170b(3) for the as-drawn Cu-Fe-Ag (IH-2). Numerous particles were observed in Cu matrix and the spacing between these particles (similar to30 nm) were found to be comparable to the activation length (170b = 43 nm). The most probable rate controlling mechanism of Cu-Fe-Ag microcomposites is suggested to be the interaction between dislocations and precipitates in Cu matrix.
10.1016-j.jallcom.2004.08.062	-1		The standard enthalpies of formation of some lanthanide-copper compounds have been measured by high-temperature direct synthesis calorimetry at 1373 +/- 2 K. The following results (in KJ/mol of atoms) are reported: 2:1 composition: Cu2Tb(-24.7 +/- 1.9); Cu2Dy(-24.4 +/- 2.3); Cu2Ho(-25.01 +/- 2.3); Cu2Er(-27.0 +/- 1.6); Cu2Tm(-23.4 +/- 2.0). 5:1 composition: Cu5Tb(-18.4 +/- 2.0);Cu5Dy(-15.7 +/- 2.2);Cu5Ho(-17.3 +/- 2.1);Cu5Er(-18.4 +/- 2.0);Cu5Tm(-18.9 +/- 2.4);Cu5Lu (-18.8 +/- 1.9). The results are compared with values available in the literature, with the predictions on the basis of the semi-empirical model of Miedema and coworkers and with the values predicted by Gschneider for lanthanide alloys. The results for the Cu alloys are also compared with the recently reported enthalpies of formation of the Ag-LA and Au-LA systems by the present authors.
10.1016-j.jallcom.2005.07.062	-1		The crystallization kinetics of a newly developed bulk amorphous CU52.5Ti30Zr11.5Ni6 alloy was investigated by differential scanning calorimetry. Under continuous heating conditions, the activation energies for the glass transition and crystallization at the onset, first peak and second peak crystallization temperatures are determined by means of Kissinger plots to be 356.86, 296.52, 288.77 and 257.19 kJ/mol, respectively. However, under isothermal conditions the average activation energy for crystallization is about 377.6 kJ/mol obtained by using the Arrhenius equation, which is much larger than that deduced from Kissinger plots. The local Avrami exponent n(x) is mostly in the range 2.4-3.1, implying that the crystallization is mainly governed by diffusion-controlled, three-dimensional growth with nearly constant nucleation rate.
10.1016-j.jallcom.2005.08.009	-1		The crystallization of gas atomized Cu47Ti33Zr11Ni8Si1 metallic glass powders subjected to annealing at temperatures above and below the glass transition temperature has been studied by X-ray diffraction (XRD), differential scanning calorimetry (DSC) and transmission electron microscopy (TEM). Nucleation occurs heterogeneously at quenched-in nucleation sites at temperature below the glass transition. The resulting nanocrystals are Cu rich . However, upon annealing in the supercooled liquid region, crystallization of Cu51Zr14 nanocrystals occurs homogeneously by a nucleation and growth mechanism. Crystallization in the supercooled liquid is diffusion-control led. The activation energies for the first-order transformation have been calculated using isochronal and isothermal approaches and do not seem to be markedly affected by annealing.
10.1016-j.jallcom.2005.12.093	12	thermodynamic; ternary; phase; data; experimental; equilibria; phase equilibria; liquid; binary; experimental data; calculated; phases; literature; model; calphad	The phase relation of the Cu-La-Sb ternary system at 693 K has been investigated mainly by means of X-ray powder diffraction with the aid of optical microscopy and differential thermal analysis. This section consists of 17 single phase regions, 33 binary phase regions and 17 ternary phase regions. Two ternary compounds CuLaSb2 and Cu3La3Sb4 were confirmed.
10.1016-j.jallcom.2006.01.022	4	transformation; martensite; martensitic; phase; shape; beta; memory; shape memory; temperature; temperatures; martensitic transformation; gamma; transformation temperatures; effect; thermal	In this paper, we study the effect of isothermal mechanical loading and unloading followed by thermal recovery on Cu-13.3Al-4.0Ni (wt%) shape memory alloy single crystal wires. The mechanical loading tests are repeated at an ambient temperature until the stress-strain response stabilizes. This study is carried out at ambient temperatures in the range 25-125 degrees C, and for an overall strain of 8.62% on one sample and 19.65% on another sample. In either case, the residual inelasticity at the end of thermal recovery was practically non-existent. The evolution of transformation temperatures was also studied, and found not to change significantly over 34 stress cycles at an overall strain of 8.62%. On the other hand, there was an increase in the range, A(f)-M-f, by 8.9 degrees C over 24 stress cycles at an overall strain of 19.65%. Finally, the stress-temperature phase diagram of the cycled material is given.
10.1016-j.jallcom.2006.01.061	-1		Alloys Cu-6 wt% Au and Cu-24 wt% Ag were prepared by casting and homogenization treatment. The effect of rare earth additions on the as-cast and homogenized microstructure was investigated by adding 0.1 wt% rare earth elements into both the alloys. Adding rare earth elements results in higher eutectic proportion in both alloys, finer primary alpha grains in the Cu-6 wt% Ag and more disperse a plates in the eutectic structure of the Cu-24 wt% Ag. Homogenization treatment produces secondary Ag-rich particles in the a matrix in both alloys and the secondary precipitates in the alloy with high Ag content have higher proportion and more distinct morphology than in the alloy with low Ag content. Adding rare earth elements can result in finer and more uniform secondary precipitates in both the homogenized alloys. The Ag concentration in the eutectic structure in all alloys significantly increases after homogenization treatment and the homogenized alloys containing rare earth elements have higher Ag concentration in the eutectic structure than those non-containing rare earth elements.
10.1016-j.jallcom.2006.02.094	4	transformation; martensite; martensitic; phase; shape; beta; memory; shape memory; temperature; temperatures; martensitic transformation; gamma; transformation temperatures; effect; thermal	The P-phase aging response of Cu-Al-Ni single crystal shape memory alloys (SMAs) within the temperature range of 473-573 K has been investigated. Alloys in austenitic (Cu-141A1-4Ni wt%, alloy A) and martensitic (Cu-13.4A1-4Ni wt%, alloy M) conditions at room temperature were considered. Aged samples show presence of beta(')(1) and gamma(')(1) martensites in both the alloys and formation Of gamma 2 precipitates in the alloy A. The differential scanning calorimetry (DSC) thermograms of the aged samples show increase in transformation temperatures as well as transformation hysteresis with aging. Dynamic mechanical analysis (DMA) was conducted on both the alloys to ascertain the role of precipitates and martensitic transition on tan 3, which characterizes the damping behaviour of the material. With aging, a steady decrease in tan 8 value was observed in both the alloys, which was attributed to the decrease in the number of interfaces per unit area with increasing aging temperature. Moreover, in alloy A, as the volume fraction of precipitate increases with aging, the movement of martensitic interfaces is restricted causing a decreased tan S.
10.1016-j.jallcom.2006.03.012	0	solidification; phase; magnetic; magnetic field; undercooling; field; liquid; separation; peritectic; immiscible; cu-; dendrite; phase separation; microstructure; primary	Adopting cyclic superheating and DSC analysis, solidification behavior of undercooled CU70Fe30 alloy was investigated. The metastable phase separation is observed if the initial melt undercooling (Delta T) is above 56 K. The primary solidification of Fe-rich phase in the phase-separated melt is due to its high nucleation driving force i.e. a high Delta T. The coarsening of Fe-rich droplets is controlled by AT and can be ascribed to the Ostwald ripening and coagulation effect in the melt.
10.1016-j.jallcom.2006.04.046	4	transformation; martensite; martensitic; phase; shape; beta; memory; shape memory; temperature; temperatures; martensitic transformation; gamma; transformation temperatures; effect; thermal	The influence of rapid quenching on the phase formation of Cu-Si alloys was investigated for silicon contents between 10 and 30 at%. Rapid quenching leads to formation of different meta-stable states depending on the chemical composition. High temperature phases eta, delta and kappa' can be preserved at room temperature. The formation of the room temperature phase epsilon can be suppressed by rapid quenching from the melt. The crystal structure of the high temperature phases was analysed by X-ray powder diffraction. Annealing of the rapidly quenched alloys at T = 500 degrees C leads to the transformations of the meta-stable phases. The equilibrium states exhibit phase compositions, which are in agreement with the generally accepted phase diagram.
10.1016-j.jallcom.2006.05.044	-1		Direct metal laser sintering (DMLS), due to its flexibility in materials and shapes, exhibits a great potential for fabricating complex shaped bulk metal matrix composites (MMCs). In the present work, the submicron WC-10% Co particulate reinforced Cu matrix composites were prepared using DMLS. The influence of reinforcement content on the sintered densification and the attendant microstructures, e.g. the dispersion homogeneity of the reinforcing particulates and the interfacial bonding ability, was investigated using scanning electron microscopy (SEM), energy disperse X-ray (EDX) spectroscopy, and atomic force microscope (AFM). It shows that using a low reinforcement content of 20 wt% results in a poor densification with severe balling phenomena, due to a higher average composite coefficient of thermal expansion (CTE) and a superheating of the melt. A heterogeneous microstructure with a significant particulate aggregation is obtained at a high reinforcement content of 40 wt%, because of a limited liquid formation and the resultant high liquid viscosity and reduced Marangoni effect. Using an optimal reinforcement content of 30 wt% leads to a uniform distribution of the reinforcing particulates and a compatible interfacial microstructure, so as to obtain a favorable sintered density of 90.3% theoretical density.
10.1016-j.jallcom.2006.06.071	-1		The refinement for the primary silicon in Cu-50wt%Si by pure Al and Cu-P master alloy was investigated in this work. The experimental results reveal that, similar to hypereutectic Al-Si alloys, All? particles can also act as the heterogeneous nucleating sites for primary silicon in Cu-Si alloys, and the primary Si can also be refined with the AlP particles. Another discovery is that pure Al can refine primary Si in Cu-50 wt. %Si alloys since Al4Cu9 can form a loop around the primary Si. To get round and small primary Si particle, it is important for AlP and surplus A] coexisting in the melt, and the addition level of A] and P should be Al:P > 1.
10.1016-j.jallcom.2006.07.133	-1		PuCoGa5 with 18.5 K has an extremely high T-c for superconductivity compared with other actinide materials having T(c)s around 2-3 K. It appears to be a high T-c superconductor in the field of actinides. After nearly 20 years of research in high T-c superconductors only Cu containing materials have T(c)s above about 30 K (exception MgB2). BCS theory cannot explain such high transition temperatures, thus other or additional coupling mechanisms, like magnetic exchange are necessary. Mixed valence, spin holes in an antiferromagnetic lattice, small energy difference between the various valences and two-dimensionality are common features of Cu and Pu containing superconductors. It can be shown in this paper that the mechanism for superconductivity is the same for Cu and Pu containing materials.
10.1016-j.jallcom.2006.08.074	-1		Nano-sized Cu-Sn alloy powders were prepared by reductive precipitation method combining with the aging treatment in constant temperature water bath at 80'C. The microstructure, morphology and electrochemical property of synthesized Cu-Sn alloy powders were evaluated by X-ray diffraction (XRD), field-emission scanning electron microscopy (FE-SEM) and galvanostatical cycling tests. The results indicated that the aged sample had uniform phase components, integrated particles, loose network-like structures and excellent electrochemical performance. When used as negative electrodes for lithium-ion batteries, the aged Cu6Sn4 and Cu6Sn5 samples delivered reversible capacities of about 340 and 370 mAh g(-1) up to 20 cycles, respectively.
10.1016-j.jallcom.2006.08.083	11	glass; bulk; metallic; bulk metallic; gfa; bmg; glassy; metallic glass; ability; bulk metallic glass; amorphous; addition; crystallization; mm; glass-forming	Amorphous alloys Cu50Pr30Ni10Al10-2-xTiXBX (x = 0, 0.05, 0.10, 0.15, 0.16 at%) have been obtained by melt-spinning technology. Results show that Cu50Pr30Ni10Al9.9Ti0.05B0.05 melt-spun ribbon at a surface velocity of 38.5 m/s is fully amorphous, while partial amorphous structure can be obtained with further additions. Differential scanning calorimeter (DSC) analyses indicate that minor addition of 0.05% Ti and 0.05% B can improve the thermal stability of melt-spun amorphous alloys, while further additions show reverse influence. The effects of Ti and B are that minor addition increases the tendency of new phases formation, and appropriate addition can suppress the formation of crystalline phases.
10.1016-j.jallcom.2006.08.109	11	glass; bulk; metallic; bulk metallic; gfa; bmg; glassy; metallic glass; ability; bulk metallic glass; amorphous; addition; crystallization; mm; glass-forming	The effects of adding small amount of aluminum to the binary Cu50Zr50 bulk metallic glass (BMG) on the thermal and mechanical properties were investigated. The Al addition was limited to 3 <= x <= 10 at% in order to form fully amorphous bulk samples. Glassy rods of 3 mm diameter of these alloys were prepared by copper mold suction casting. The (Cu50Zr50)(100-x)Al-x BMGs (x = 0 and 3 <= x <= 10 at%) were characterized with differential scanning calorimetry (DSC), X-ray diffraction (XRD), Vickers microhardness test and nanoindentation, respectively. The glass transition temperatures, crystallization temperatures and super-cooled liquid regions of the specimens increased with increasing Al content. The microhardness of the specimens also increases with increasing Al content. Room temperature nanoindentation was carried out on the cross-section of the rods. The results showed that the nanohardness and creep displacement were dependent on the Al content.
10.1016-j.jallcom.2006.08.139	4	transformation; martensite; martensitic; phase; shape; beta; memory; shape memory; temperature; temperatures; martensitic transformation; gamma; transformation temperatures; effect; thermal	In the ternary system Au-Cu-Al, the 0 phase has a displacive transformation which can be tailored for a shape memory effect. The sequence of allotropic transformations of the P phase as a function of temperature and cooling conditions is reported in this work. The structure of the martensite (monoclinic) and the type of parent phase are identified. Rapid solidification is employed as a tool for freezing the high temperature modification and compared to quenching from the solid state. DSC analyses clearly demonstrate the thermodynamic order of transformations and the temperatures of the forward and reverse martensitic transformation. A transformation from metastable B2 to L2(1) has been revealed for the first time. The transformation is endothermic and irreversible. The thin ribbon sample has been used to show the one-way shape memory effect.
10.1016-j.jallcom.2006.08.140	-1		The crystallization kinetics of partially crystalline Cu47Ti33Zr11Ni8Si1 gas atomized powder (GAP) and composites was studied by differential scanning calorimetry. The activation energy for crystallization as determined by the Kissinger equation is nearly equal for the particle-free powder (3.43 +/- 0.40 eV) and the composite (3.11 +/- 0.22 eV). The activation energy of crystallization derived from isothermal annealing experiments is nearly similar for the GAP (4.53 +/- 0.40 eV) and the composite (4.25 +/- 0.40 eV). The values of the Avrami exponent suggest that the crystallization is diffusion controlled. The local Avrami exponent suggests that surface nucleation is active in GAP but bulk crystallization dominates in milled composite powder.
10.1016-j.jallcom.2006.08.149	11	glass; bulk; metallic; bulk metallic; gfa; bmg; glassy; metallic glass; ability; bulk metallic glass; amorphous; addition; crystallization; mm; glass-forming	(CU0.5Zr0.425Ti0.075)(99)Sn-1 bulk metallic glass with a glass transition temperature of 683 K and a supercooled liquid region of 47 K was synthesized by copper mold casting. The bulk glassy alloy exhibits high strength of 1810 MPa and superior plasticity in uniaxial compression at ambient temperature. High resolution transmission electron microscopy for the bulk glassy sample subject to a plastic strain of 3% shows the formation of nanocrystallites in the glassy matrix. The plastic deformability of the (CU0.5Zr0.425Ti0.075)(99)Sn-1 bulk metallic glass is attributed to the in situ precipitation of nanocrystallites during the compression.
10.1016-j.jallcom.2006.08.181	11	glass; bulk; metallic; bulk metallic; gfa; bmg; glassy; metallic glass; ability; bulk metallic glass; amorphous; addition; crystallization; mm; glass-forming	Alloys of composition Cu55Hf45-xTix with 5 <= x <= 45 at% and Cu65Hf35-x Ti-x with 5 <= x <= 35 at .% have been investigated. Samples were chill block melt spun to ribbon and produced as cylindrical rods by suction casting into a stepped copper die. All alloys investigated in both series were fully vitrified when melt spun to ribbon of thickness similar to 25 mu m. The compositions x = 20 and 25 within the Cu55Hf45-xTix series and x = 15 and 20 within the Cu65W35-xTix series were found to be the best glass formers, with no crystalline phases detected by XRD for 3 and 4 mm diameter sections, respectively. The composition ranges of highest GFA also had the highest reduced glass temperatures for each of the ranges studied.
10.1016-j.jallcom.2006.08.298	4	transformation; martensite; martensitic; phase; shape; beta; memory; shape memory; temperature; temperatures; martensitic transformation; gamma; transformation temperatures; effect; thermal	Rapid solidification methods (planar flow casting and twin roll casting) have been used to improve and simplify processing of shape memory alloys. Our goal is to synthesize amorphous as-cast materials and then near-net shaping can be obtained while working in the supercooled liquid temperature region. Materials are thereafter crystallized in order to recover a reversible austenite-martensite transformation. Alloying equiatomic Ni-Ti intermetallic compound with selected elements leads to better glass forming ability (GFA). Despite the fact that compositional requirements for obtaining thermoelastic reversible martensitic, transformation and glass formation are different and contradictory, the pseudo-binary alloys developed by substitution of Zr, Hf for Ti, and Cu, Co, Pd, Sn for Ni are good candidates to exhibit both phenomena. We report here a choice of compositions, which after fast cooling, are amorphous and demonstrate a superplastic behaviour in the triangle T (T-x-T-g) region. After an adequate thermal treatment, a martensitic phase is obtained for some compositions, and such alloys demonstrate shape memory and superelastic properties.
10.1016-j.jallcom.2006.08.300	-1		Strain rate sensitivity is measured using jump test, with respect to strain rate and temperature on nanostructured copper. The nanometal, prepared by powder metallurgy technique, is tested at room temperature over the range 1 x 10(-5) s(-1) to 1.8 x 10(-2) s(-1) and at moderate temperatures, between 353 K and 393 K (homologous temperature TITm: 0.26-0.29), over the range 1 x 10(-5) S-1 to 9 x 10(-3) S-1. Results are discussed in terms of potential ductility and forming ability.
10.1016-j.jallcom.2006.08.304	-1		The Cu- and Ni-based bulk metallic glass matrix composites were fabricated by spark plasma sintering of a mixture of gas-atomized metallic glass powders and ductile brass powders. The brass powders added for the enhancement of plasticity are well distributed in the matrix after consolidation. The matrix of the composite materials remains as a fully amorphous phase after consolidation process. With increasing the brass content, the level of plasticity strain increased, although the level of strength decreased. The successful consolidation of metallic glass matrix composite with high density was attributed to viscous flow in the supercooled liquid state during spark plasma sintering.
10.1016-j.jallcom.2006.08.307	16	wear; composite; composites; powders; milling; particles; powder; wt; sliding; friction; hardness; matrix; mechanical; surface; properties	Cu-NbC nanocomposites with nominal compositions of 5, 10 and 20 vol.% of NbC were produced in situ via MA from elemental powders. The powders were milled for 1, 2, 4, 8, 16 and 32 h . The as-milled powders were characterised by X-ray diffraction (XRD) and scanning electron microscopy (SEM). X-ray diffraction results showed that the niobium carbide phase is formed in the early stages of milling and that the time necessary to complete the reaction ranges from I to about 8 h of milling.
10.1016-j.jallcom.2006.08.340	11	glass; bulk; metallic; bulk metallic; gfa; bmg; glassy; metallic glass; ability; bulk metallic glass; amorphous; addition; crystallization; mm; glass-forming	Thermal stability and crystallization kinetics of an as-prepared Cu35Ag15Zr45Al15 metallic glass have been investigated by differential scanning calorimeter and X-ray diffraction. It is found that Cu35Ag15Zr45Al15 has a supercooled liquid region as large as 114 K at a heating rate of 40 K/min. Crystallization kinetic studies show that glass transition as well as crystallization behave in a typical kinetic nature with Kauzmann temperature Tk about 610 K and activation energies of E-g =483 +/- 75 kJ/mol and E-x =253 +/- 8 kJ/mol for glass transition and crystallization, respectively. The addition of Ag in the Cu-Zr-Al alloy system might improve the packing efficiency and increase the complexity of the system. Consequently, an excellent thermal stability is achieved for the Cu35Ag15Zr45Al5 metallic glass.
10.1016-j.jallcom.2006.11.026	4	transformation; martensite; martensitic; phase; shape; beta; memory; shape memory; temperature; temperatures; martensitic transformation; gamma; transformation temperatures; effect; thermal	The shape change of Cu-13Zn-15A1 shape memory alloy on successive heating at a heating rate of 5 degrees C/min has been studied. The behavior of shape change is strongly temperature dependent. As the heating temperature is below 320 degrees C, the stabilization phenomenon of the martensite appears, and the first reverse shape memory effect (FRSME) in the Cu-13Zn-15A1 alloy occurs due to the martensitic nature transformation that involved in the martensite stabilization process. At the temperature between 320 and 400 degrees C, the forward shape memory effect (FSME) can be caused by the reverse transformation of the stabilized martensite. The second reverse shape memory effect (SRSME) in the Cu-13Zn-15A1 alloy occurs when the ribbon is heated to above 450 degrees C and subsequently air-cooled to room temperature, this phenomenon attributes to the growth of an asymmetric martensite phase due to the constraining of a-phases distributed along the boundary of the new-formed martensite variants.
10.1016-j.jallcom.2006.11.054	-1		This study aims at fabricating Cu-based bulk amorphous alloys by a spark plasma sintering (SPS) method. Consolidation temperature, consolidation pressure, and holding time were established to obtain good microstructures and compressive properties of consolidated amorphous alloys. Bulk amorphous alloys having a few micropores and nanocrystalline phases could be obtained with a consolidation pressure of 80 MPa, but were fractured in an intergranular mode along prior powder boundaries. Microstructures and compressive properties of the alloys consolidated with a pressure of 300MPa were significantly modified as prior amorphous powders were sufficiently bonded without micropores. Fractographic investigation of these alloys indicated that vein patterns appeared on fracture surfaces as amorphous powders were strongly bonded during the high-pressure consolidation. These findings suggested that the high-pressure consolidation was effective in suppressing the crystallization of amorphous phases and in strongly bonding amorphous powders.
10.1016-j.jallcom.2007.01.139	2	corrosion; surface; film; electrochemical; films; spectroscopy; layer; current; solution; potential; resistance; composition; x-ray; ions; showed	The corrosion characteristics of Cu-6% Ni-4% Sn-x% Cr alloys in an acid-chloride solution (0.1 M H2SO4+0.0056M NaCl) at pH 1.2, were studied as a function of the chromium content. Three kinds of Cu-6% Ni-4% Sn-x% Cr alloys were prepared by melting and casting, followed by thermomechanical treatments. The corrosion behavior of the Cu-6% Ni-4% Sn-x% Cr alloys was investigated using electrochemical corrosion test and surface analyses (optical microscopy, electron probe microanalysis and scanning electron microscopy). The addition of Cr was found to prevent the localized corrosion behavior, which is caused by the decreased Sn-rich precipitates in Cu-6% Ni-4% Sn-x% Cr alloys. These precipitates induced galvanic corrosion due to the difference of the chemical composition.
10.1016-j.jallcom.2007.01.173	12	thermodynamic; ternary; phase; data; experimental; equilibria; phase equilibria; liquid; binary; experimental data; calculated; phases; literature; model; calphad	High temperature heat contents of the Cu-Zr system alloys were measured over temperature range from 880 to 1470 K using a drop calorimeter. The enthalpies of fusion of some solid compounds were determined by the heat content-temperature plots and the entropies of fusion were calculated. Enthalpies of mixing in the liquid Cu-Zr system were measured by high temperature reaction calorimetry in the concentration range of x(Zr) = 0.182-0.667 at 1443 K. This system has negative enthalpies of mixing over the measured concentration range. The standard enthalpies of formation at 298.15 K of Cu9Zr2, Cu51Zr14, Cu8Zr3, Cu10Zr7 and CuZr2 compounds were determined from the obtained data for the heat contents and enthalpies of mixing. Based on the experimental data, published thermodynamic and phase diagram data, the Cu-Zr binary system was analyzed using Redlich-Kister polynomial equation. The thermodynamic properties and the phase diagram calculated from the optimized parameters agree well with the experimental data.
10.1016-j.jallcom.2007.02.119	-1		A study of the coarsening process of the decomposed phases was carried out in the Cu-34 wt% Ni-4 wt% Cr and Cu-45 wt% Ni-10 wt% Cr alloys using transmission electron microscopy. As aging progressed, the morphology of the coherent decomposed Ni-rich phase changed from cuboids to platelets aligned in the < 1 0 0 > Cu-rich matrix directions. Prolonged aging caused the loss of coherency between the decomposed phases and the morphology of the Ni-rich phase changed to ellipsoidal. The variation of mean radius of the coherent decomposed phases with aging time followed the modified LSW theory for thermally activated growth in ternary alloy systems. The linear variation of the density number of precipitates and matrix supersaturation with aging time, also confirmed that the coarsening process followed the modified LSW theory in both alloys. The coarsening rate was faster in the symmetrical Cu-45 wt% Ni-10 wt% Cr alloy due to its higher volume fraction of precipitates. The activation energy for thermally activated growth was determined to be about 182 and 102 kJ mol(-1) in the Cu-34 wt% Ni-4 wt% Cr and Cu-45 wt% Ni-10 wt% Cr alloys, respectively. The lower energy for the former alloy seems to be related to an increase in the atomic diffusion process as the chromium content increases. The size distributions of precipitates in the Cu-Ni-Cr alloys were broader and more symmetric than that predicted by the modified LSW theory for ternary alloys.
10.1016-j.jallcom.2007.02.139	-1		The structural and magnetic properties of nanocrystalline Cu-Ni and Cu-Ni-Co alloys prepared by mechanical alloying and subsequent isothermal annealing in the temperature range of 350-650 degrees C has been investigated systematically. The average grain sizes of Cu-Ni and Cu-Ni-Co alloy systems were found to be in the range of 5-8 nm after 30 h of milling and 21-40 nm after isothermal annealing of as-milled samples. Here, it is shown that the magnetic properties (H-c, M-r and M-s) of the nanocrystalline alloys undergo changes by the variation in microstructural constituents, grain size and evolution of phases. The alloy containing 10 wt% Co shows notable improvement in the magnetic properties. Phases present in the ball milled samples and the isothermally annealed ball milled product were identified and characterized by X-ray diffraction (XRD) and differential scanning calorimetric (DSC) techniques and the results were correlated with the magnetic properties of the alloys.
10.1016-j.jallcom.2007.04.017	12	thermodynamic; ternary; phase; data; experimental; equilibria; phase equilibria; liquid; binary; experimental data; calculated; phases; literature; model; calphad	The thermodynamic assessments of the Cu-Th and Mo-Th binary systems were carried out by using Calculation of Phase Diagrams (CALPHAD) method on the basis of the experimental data including the thermodynamic properties and phase equilibria. The Gibbs free energies of the liquid, bcc, and fcc phases are described by the subregular solution model with the Redlich-Kister equation and those of the four intermetallic compounds Cu6Th, Cu3.6Th, Cu2Th and CuTh2 in the Cu-Th binary system were described by the sublattice model. A set of self-consistent thermodynamic parameters are obtained, and the calculated phase diagrams and thermodynamic properties are presented and compared with the experimental data from literatures. The calculated thermodynamic properties as well as phase diagrams are in good agreement with the experimental data.
10.1016-j.jallcom.2007.04.254	4	transformation; martensite; martensitic; phase; shape; beta; memory; shape memory; temperature; temperatures; martensitic transformation; gamma; transformation temperatures; effect; thermal	Four sets of Cu-Al-Mn shape memory alloys, in the range of 10-15 wt% of aluminum and 0-10 wt% of manganese, were prepared by ingot metallurgy. The Al content was kept constant, whereas the Mn content was varied in two sets. The Mn content was kept constant in the other two sets, whereas the Al content was varied. The transformation temperatures, shape memory and superelastic behavior of these SMAs are highly sensitive to variations in aluminum and manganese content. The influence of variation in aluminum and manganese on these properties has been studied by differential scanning calorimetry, bend and tensile tests. With an increase in the aluminum and manganese concentrations of the alloy, the martensite morphology is modified and the transformation temperatures decrease. A linear regression analysis correlates the changes in aluminum and manganese concentration to the variations in the transformation temperatures. There is no appreciable variation in the shape memory effect with variation in the concentrations of aluminum and manganese. On the other hand, an increase in the aluminum content decreases the superelasticity of the alloys, while at the same time an increase in the manganese content increases it.
10.1016-j.jallcom.2007.04.307	16	wear; composite; composites; powders; milling; particles; powder; wt; sliding; friction; hardness; matrix; mechanical; surface; properties	The mixture of electrolytic copper powder with 5 wt% of commercial Al2O3 powder (average particle size: 15 and 0.75 mu m, respectively) and the inert gas atomized prealloyed copper powder (average particle size: 30 mu m) containing 2.5 wt% aluminum were separately milled in air up to 20 h in the planetary ball mill. During milling aluminum in the prealloyed copper powders was oxidized in situ by internal oxidation with oxygen from the air forming very fine nano-sized Al2O3 particles. The internal oxidation of 2.5 wt% aluminum generated 4.7 wt% of Al2O3 in the copper matrix. Powders and compacts were characterized by light and scanning electron microscopy (SEM), electron probe microanalysis (EPMA) and X-ray diffraction analysis. Microhardness and electrical conductivity were also included in measurements. The microhardness of Cu-2.5 wt% Al compacts was 3.6 times higher than that of compacts processed from electrolytic copper powder. This increase in microhardness is a consequence of a fine dispersion of Al2O3 particles and refined grain structure. The average values of electrical conductivity of compacts processed from Cu-5 wt% Al2O3 and Cu-2.5 wt% Al powders previously milled for 20 h and were 88% and 70% IACS, respectively, which is a rather significant increase if compared with values of 60% and 23% IACS of compacts processed from as-received and non-milled powders. The microhardness of 20-h milled compacts decreases with the heat treatment at 800 degrees C. Due to the effect of nano-sized Al2O3 Particles Cu-2.5 wt% Al compacts show lower decrease in microhardness. The results are discussed in terms of the effect of Al2O3 Particle size and fine grain structure on the reinforcing of the copper matrix. (C) 2007 Elsevier B.V. All fights reserved.
10.1016-j.jallcom.2007.05.064	-1		The synthesis of Cu100-xAgx (0.05 at% < x < 0.30 at%) nanoparticles using an evaporation-condensation process has been studied. Particular attention has been paid to the composition of the as-prepared powders. Compared to the master alloy, systematic enrichment in Ag of the particles is observed at the beginning of the synthesis but a continuous decrease in the Ag content of the powders is observed during the process. Even though, after de-agglomeration, the chemical composition of the powders is, in average, homogeneous. We have shown that optimized synthesis conditions give spherical particles with a mean diameter of 50 nm and a reasonable yield rate.
10.1016-j.jallcom.2007.06.026	-1		Bulk copper alloys with nano TiB2 particles were prepared by a new technology that combining in situ reaction with rapid solidification. Appropriate reactor shape and procedure parameters are as follows: S-0/(S-1 + S-2) = 0.8-1.2, L-0/D-0 = 10-15, theta = 60-90 degrees, melt temperature 1350-1450 degrees C, air pressure 0.2-0.3 MPa. A special water-cooled copper mold can satisfy the need of rapid solidifying Cu-TiB2 alloy melt. The average size of TiB2 particle in the copper matrix synthesized by using optimal parameters is about 20 nm.
10.1016-j.jallcom.2007.06.118	2	corrosion; surface; film; electrochemical; films; spectroscopy; layer; current; solution; potential; resistance; composition; x-ray; ions; showed	Ni57Ti18Zr20Si2Sn3 and Cu54Ni6Zr22Ti18 amorphous feedstock fabricated by gas atomization were deposited on mild steel substrate by the kinetic spray technique. These as-sprayed coating samples were annealed at each suitable temperature to form three different matrix structures: amorphous, partially crystallized on amorphous and fully crystallized. Each structure was confirmed by XRD, TEM and DSC analyses. In the results of electrochemical tests conducted in a simulated acid rain solution, the amorphous structured coatings exhibit a superior corrosion resistance to the crystallized coatings with high polarization resistance, and the corrosion resistance decreased with increasing fraction of crystallization. As a function of time, the amorphous structure coatings maintained high protective efficiency and low porosity for 9 days immersion. The Ni-based alloy coatings showed better corrosion resistance than the Cu-based ones for each type of structure.
10.1016-j.jallcom.2007.08.080	16	wear; composite; composites; powders; milling; particles; powder; wt; sliding; friction; hardness; matrix; mechanical; surface; properties	W-20 wt% Cu powder mixture was mechanically alloyed by high-energy ball milling for various times and the effect of mechanical alloying (MA) on the sintering response of the composite compacts was investigated. The densification, microstructure, hardness and electrical conductivity after solid phase sintering (SPS) and liquid phase sintering (LPS) were examined. It was shown that the microstructure of mechanically alloyed powder profoundly influence the sintering response, i.e. a meaningful relationship between the sintering kinetics and the milling time was observed. It is suggested that MA disintegrates the W-W particle networks and increases the contribution of solid phase sintering (SPS) of nanostructured Cu and W particles on the densification. Higher hardness and conductivity were achieved by prolonged MA and SPS, indicating a lower W-W contiguity of the milled powders compared with the conventionally prepared W-Cu composite. On the other hand, depression of the melting temperature of copper up to 145 degrees C was noticed by affording a prolonged MA. The lower melting temperature and finer distribution of the Cu particles in the W matrix enhanced the densification during LPS and improved the homogeneity and properties of the final product. (C) 2007 Elsevier B.V. All fights reserved.
10.1016-j.jallcom.2007.10.033	-1		Cu-W alloy films were prepared by magnetron sputtering. Their microstructure, hardness, elastic modulus and plastic deformation were investigated by various technologies. The results show that Cu-W amorphous alloy films are formed in the composition range from Cu36W64 to Cu75W25, and out of this range solid solutions are formed. Both the hardness and elastic modulus of Cu-W amorphous alloy films are lower than their rule-of-mixture values. The load-displacement curves of Cu-W amorphous alloys with lower Cu content exhibit obvious serrated flow at lower strain rate. Serrations are suppressed at higher strain rate and higher Cu content. For all Cu-W amorphous alloy films, shear bands are observed and their number and density increase with increasing Cu content. indicating that the details of the plastic deformation of Cu-W amorphous alloys arc material-related.
10.1016-j.jallcom.2007.10.101	2	corrosion; surface; film; electrochemical; films; spectroscopy; layer; current; solution; potential; resistance; composition; x-ray; ions; showed	The corrosion behavior of sputtered Cu-Zr nanostructured thin films (the grain sizes: 10-20 nm) was investigated in 0.1 mol/L HCl solution using electrochemical and surface analysis techniques. The corrosion properties and the corroded surface morphologies of the Cu-Zr nanostructured films depend strongly on the alloy compositions. A model has been proposed to clarify the competition between the dissolution of Zr and the rearrangement of Cu on the electrode surface, in order to explain the formation of porous structure after corrosion. A uniformly porous surface is formed when the process of the selective dissolution of Zr and the rearrangement of Cu reaches an equilibrium state.
10.1016-j.jallcom.2007.10.122	-1		A Cu-Sn-Zn-Pb alloy was irradiated by ultraviolet nitrogen laser pulses (N-2 laser, wavelength 337 nrn, pulse duration 6 ns, frequency 1 Hz, power 0.5 MW and average power density 0.67 GW/m(2)). The surface topography and microstructure were mainly studied by scanning electron microscopy, and a focused ion beam. The non-homogenized spatial beam profile resulted in the activation of several ablative mechanisms, the main being phase explosion and hydrodynamic instability. They caused a crater to be formed, surrounded by a raised rim and wavelike structure in a halo. FIB cross-sectioning and imaging showed a shallow (few micrometers) molten and resolidified surface layer. Streaks were observed in the heat-affected zone beneath the molten layer, indicating partial recrystallization of initially cold-worked material.
10.1016-j.jallcom.2007.12.020	-1		The Cu-12 wt% Fe microcomposite of filamentary composite structure was prepared by heavy cold drawing. The microstructure was observed, and the mechanical properties and electrical conductivity were determined for the microcomposite annealed at different temperatures. Annealing at temperatures lower than 300 degrees C results in slight decrease in the strength and hardness and a certain increase in the conductivity. Obvious recrystallization occurs in the filamentary structure at higher than 400 degrees C. The filaments are basically replaced by equiaxial recrystallized grains at higher than 500 degrees C. The strength and hardness markedly decrease while the conductivity markedly increases with annealing temperatures from 300 to 600 degrees C. However, the conductivity decreases with annealing temperature from 600 to 700 degrees C. A suitable matched relationship between the mechanical properties and electrical conductivity can be obtained if the boundary migration of fine recrystallized grains is only restricted within the filaments of the heavily deformed structure during annealing.
10.1016-j.jallcom.2007.12.070	-1		0.3 wt% rare-earth elements were added into Cu-12 wt. % Ag and sonic compound particles were observed in the eutectic colonies. The chemical composition and crystal structure of the compound were determined. The compound containing rare-earth elements can be represented as (Cu, Ag)(6)(Ce, La) and has a similar crystal structure to Cu6Ce of orthorhombic system. The (Cu, Ag)(6) (Ce, La) particles are hardly deformed during cold drawing. There is, an incoherent interface between file compound and Ag-rich phase. Higher strain concentration and dislocation density lire presented in lite local region of Ag filament,, close to the particles in the alloy of heavy drawing.
10.1016-j.jallcom.2007.12.075	12	thermodynamic; ternary; phase; data; experimental; equilibria; phase equilibria; liquid; binary; experimental data; calculated; phases; literature; model; calphad	The solidus and liquidus in the system Cu-Ni over the entire composition range were determined by using the spot-technique. The solidus temperatures of some nickel rich alloys were also investigated using differential thermal analysis (DTA). The experimental data obtained were shown to be in agreement with the assessed values. The experimental Set up Used in this study Was in improvised version of the apparatus used in earlier studies. It was demonstrated that by using this set up the temperatures of melting transitions could be determined within +/- 2K. Temperature calibration was carried out by determining the melting points of pure metals viz., Au, Ni and Cu. The salient features and file utility of the 'spot-technique' were also demonstrated.
10.1016-j.jallcom.2008.01.107	-1		Cu3Sn phase with the D0(19) structure is observed in Cu-Sn alloy by transmission electron microscopy, The structure is determined by electron diffraction, high-resolution transmission electron microscopy and high-angle annular dark-field imaging techniques. To the best of our knowledge this structure has not been reported before in Cu3Sn compounds. Transmission electron microscopy revealed high-density antiphase boundaries lying on the (0 (1) over bar 10) planes with translation vectors of (a/2)((2) over bar 110) in the D0(19) Cu3Sn. (C) 2008 Elsevier B.V. All rights reserved
10.1016-j.jallcom.2008.02.013	-1		Thermal stabilities of deformation processed Cu-12Fe and Cu-11Fe-6Ag composites were investigated through isochronic aging treatments. The morphology transitions of the Fe filaments and the Cu matrix were investigated by scanning electron microscopy (SEM), transmission electron microscopy (TEM) and energy dispersive spectrometer (EDS) equipped on the TEM. The results show that during the annealing treatment the Fe filaments experienced longitudinal splitting, cylinderization, break-up and spheroidization. Addition of Ag can reduce the thermal stability of the deformed Fe filaments and accelerate the precipitation kinetics of Fe from the Cu matrix.
10.1016-j.jallcom.2008.03.009	4	transformation; martensite; martensitic; phase; shape; beta; memory; shape memory; temperature; temperatures; martensitic transformation; gamma; transformation temperatures; effect; thermal	Cu-Al-Ni hypoeutectoidal shape memory alloys have been studied. Polycrystalline specimens have been quenched (into water at room temperature) after heat treatment at 850 degrees C and followed by two successive runs from room temperature to 650 degrees C and inversely. The microstructural and thermodynamic studies presented in this work have been performed using DSC (differential scanning calorimetry), X-ray diffraction analysis at a variable temperature and TEM (transmission electron microscopy) analysis. Stable phase precipitation of AlNi type was observed to appear in these hypoeutectoidal alloys. The thermodynamic study has showed that the martensitic transformation in heating needs a greater energy than that of the reverse transformation.
10.1016-j.jallcom.2008.05.005	4	transformation; martensite; martensitic; phase; shape; beta; memory; shape memory; temperature; temperatures; martensitic transformation; gamma; transformation temperatures; effect; thermal	Aging the 18R martensitic phase in CuZnAl alloys changes the critical beta <-> 18R transformation temperatures, and the critical transformation stresses. This diffusional phenomenon is known as martensite stabilization. In this work, the role of vacancy concentration and thermal treatment temperatures on the stabilization kinetics is analyzed. It is found that temperature determines the stabilization time start, while the initial vacancy concentration controls the stabilization rate. A model considering the evolution of vacancies during the stabilization time permits qualitatively a description of the process.
10.1016-j.jallcom.2008.06.109	-1		The refinement treatment of martensite in Cu-11.38 wt%Al-0.43 wt%Be (Cu-22.71 at%Al-2.57 at%Be) shape memory alloy was investigated in this work. The results show that the aging treatment at a temperature near the eutectoid temperature caused numbers of oval-like renucleated parent phase in the matrix. Following the TEM-EDX analysis, a concentration gradient of Al content is caused because the A]rich renucleated phase formed in the matrix. Therefore, the occurrence immediately provides potential sites for heterogeneous nucleation. When a large number of martensites grow simultaneously, mutual collision and obstruction occur, creating a cluster microstructure of fine martensite and improving the recovery ability of the alloy. Crown Copyright
10.1016-j.jallcom.2008.07.008	16	wear; composite; composites; powders; milling; particles; powder; wt; sliding; friction; hardness; matrix; mechanical; surface; properties	LM13 alloy is widely used in piston industry, due to its low coefficient of thermal expansion, excellent castability and hot tear resistance. In this research effect of casting process on wear behavior of LM13 alloy was investigated. First, samples were produced using two casting processes and heat treated. Then wear behavior of these samples under dry sliding condition was examined. Results of hardness and strength tests indicated that squeeze cast specimens exhibited higher mechanical properties. Wear experiment results showed that in both squeeze and gravity cast specimens, amount of weight loss increases with increase in sliding distance which is accompanied by reduction in wear rate and friction coefficient. A comparison between two samples demonstrated that squeeze sample had better tribological behavior. Casting process variation causes decrease in friction coefficient from 0.4 to 0.2 for squeeze cast samples and decrease in weight loss of these samples. Squeeze cast samples had better surface quality and in these samples abrasive, adhesive and delamination are dominant wear mechanisms while in gravity cast samples abrasive, adhesive and surface fatigue are the dominant wear mechanisms.
10.1016-j.jallcom.2008.07.148	-1		Metallic glasses exhibit particularly attractive mechanical properties, like high stresses to fracture and large elastic strain (up to 2%), but they show generally low plasticity. Aim of this work is to investigate the glass forming range in the Cu-Y system, in order to form the ductile CuY phase (CsCl structure) upon crystallization. Cu58Y42, Cu50Y50 and Cu33Y67 alloys have been prepared by rapid solidification and copper mould casting, obtaining ribbons and cylindrical shaped ingots, with diameter of 2 mm. Fully amorphous, partially amorphous and fully crystalline samples have been obtained for different compositions and quenching conditions. In some cases, the X-ray diffraction results, analysed using the Rietveld method, showed CuY nanocrystals embedded in an amorphous matrix. The microstructure was studied by transmission electron microscopy (TEM) and the presence of nanocrystals of the ductile phase CuY has been Microhardness results showed a softening of the amorphous phase due to the presence of CuY narrocrystals and a hardening due to the Cu2Y phase.
10.1016-j.jallcom.2008.07.157	-1		The electrochemical properties and surface characteristics of Cu-Zr-Ag-Al-Nb bulk metallic glasses (BMGs) were investigated. The alloys exhibit excellent corrosion resistance after immersion in 1 N H2SO4 and 1 N NaOH. The corrosion rates of the alloys in chloride-ion-containing solutions significantly decrease by alloying with Nb element. The formation of Zr- and Nb-enriched surface films could be responsible for the high corrosion resistance.
10.1016-j.jallcom.2008.08.139	11	glass; bulk; metallic; bulk metallic; gfa; bmg; glassy; metallic glass; ability; bulk metallic glass; amorphous; addition; crystallization; mm; glass-forming	To circumvent the limited plasticity of bulk metallic glasses (BMGs), heterogeneous materials with glassy matrix and different type and length-scale of heterogeneities (micrometer-sized second phase particles or fibers, nanocrystals in a glassy matrix, phase separated regions, variations in short-range order by clustering) have been reported. We developed bulk metallic glasses and glass matrix composites in martensitic Zr-Cu-base alloys. Large plasticity can be obtained from microstructure consisting of either a glassy structure, or for alloys with martensitic second phase embedded in a glassy matrix. This type of glasses and glass-matrix composites are able to achieve high strength together with pronounced work-hardening. We explore the possibilities to synthesize such in situ composite microstructures based on shape memory alloys (M-Glasses) through metal mold casting.
10.1016-j.jallcom.2008.09.003	4	transformation; martensite; martensitic; phase; shape; beta; memory; shape memory; temperature; temperatures; martensitic transformation; gamma; transformation temperatures; effect; thermal	The copper-based shape memory alloys (SMA) are susceptible to be decomposed by precipitation beyond 220 degrees C. In this paper, the effects of isothermal and continuous heating on eutectoid Cu-based SMA up to 400 degrees C are evaluated by using differential scanning calorimetry (DSC), X-ray energy dispersion spectroscopy (EDX), X-ray diffraction (XRD) and scanning electron microscope/transmission electron microscope (SEM/TEM) techniques. The experiments show that a succession of two precipitation processes appears. The first process to appear is a cellular process composed of a supersaturated Al solid solution alpha(s) and an intermetallic compound gamma(2), i.e., beta(1) -> alpha(s) + gamma(2). The second process results from alpha(s) evolving into a nanometric globular precipitates of gamma(2) and an unsaturated alpha, i.e., alpha(s) -> gamma(2) + alpha.
10.1016-j.jallcom.2008.10.022	13	clusters; atomic; glass; atoms; composition; dynamics; metallic; icosahedral; glasses; simulations; molecular; cu-zr; molecular dynamics; metallic glasses; structural	We have evaluated the predictive ability of a simple method combing topological and chemical analysis with the normalized configurational entropy S-config/R in rapidly locating the bulk metallic glass-forming composition region, in Cu-Zr binary and Cu-Zr-Ti, Cu-Zr-Al, Cu-Zr-Ni-Ti, Cu-Zr-Ni-Al-Ti multicomponent alloy systems. It was found that the chemical mixing enthalpy between constituents and efficient cluster packing are two dominate factors in BMG formation, and BMGs form in composition region with S-config/R ranging from about 0.8 to about 1. The predicted composition regions of bulk metallic glasses (BMGs) are in good agreement with experimental results. BMG formation is most probably a compromise between topological and chemical effects. BMGs can form with efficient cluster packing, even they are not the most thermodynamically stable ones. At the same time, BMGs can also form with large negative chemical mixing enthalpy, even they are not the most efficiently packed ones. This method could be used to rapidly locate BMG-forming composition region, especially when eutectic composition is unknown.
10.1016-j.jallcom.2008.12.005	-1		Supersaturated nanocrystalline (16-19 nm) Cu(50)Ag(50) and Cu(70)Ag(30) solid solutions are synthesized by high-energy ball milling. Varying the milling time fcc solid solutions with different lattice parameters are obtained. Thus an increase of the lattice constant that levels off after 20 h of milling is registered for the Cu(50)Ag(50) solid solution. At the same time broad overlapped exothermic effects in the temperature range of 170-370 degrees C are detected by DTA. These can be associated mainly with solid solution decomposition and a grain growth process. Electrochemical selective dissolution reveals a quasi-critical potential of Cu dissolution in Cu(70)Ag(30) that is shifted 40 mV positively, compared to the dissolution potential of pure Cu, thus ascertaining the Cu (Ag) solid solution formation. The linear area development with the in-depth progress of the Cu dissolution front confirms the dealloying applicability for fabrication of nanoporous Ag structures in this case.
10.1016-j.jallcom.2008.12.008	-1		In this paper, a new preparation technology is proposed to manufacture nano-alumina particle-reinforced copper alloy. The new preparation technology includes three processes: mechanical alloy, hydrogen sintering and explosive compaction. The microstructure indicates alpha Al(2)O(3) particles are dispersed in copper matrix and still keep the nanometer scale. We apply three kinds of explosion pressure, which is 2 GPa, 4 GPa and 6 GPa respectively, to research the influence of explosion pressure on compaction quality. The detection results show that the relative density and hardness of samples increase with the rise of explosion pressure, but diameter of Mach hole increase thereupon too. The most suitable explosion pressure for Cu/alpha Al(2)O(3) mixed powder is 4 GPa under the pressure the sample's relative density reaches 98.61% and hardness reaches 112 HV. Crown Copyright
10.1016-j.jallcom.2008.12.060	8	hot; deformation; strain; strain rate; dynamic; hot deformation; recrystallization; dynamic recrystallization; flow; rate; flow stress; compression; constitutive; degrees; stress	The changes of flow stress, hardness and microstructure of the Cu-0.23vol%Al2O3 alloy in the high temperature plastic deformation process have been investigated. The differences of flow stress of this alloy compressed under different conditions are significant, yet, mainly including three different stages. The constitutive equation for its peak yield stress, strain rate and temperature was also established, which can evaluate its peak yield stress better. With the increasing of temperature and strain rate, the changes of hardness and microstructure also have its own uniqueness. The higher strain rate is favorable to the formation of fine subgrains with a clear subgrain boundary.
10.1016-j.jallcom.2009.01.027	6	grain; deformation; strain; strength; dislocation; cu-; tensile; size; ecap; grain size; sfe; ductility; hardening; high; stress	Tensile tests were performed at room temperature to measure the strength and stress-relaxation response of Cu-42.2 at%Zn-0.6 at%Pb polycrystals of grain size 5,7,9 and 11 mu m. The values of the strength parameters, namely yield stress, ultimate tensile strength and fracture stress, were found to decrease with the increase in grain size in accordance with the Hall-Petch law, whereas the ductility decreased with the reduction in grain size. The stress-relaxation response studied at constant strain was logarithmic in nature. For a given initial stress level sigma(o), from which relaxation at constant strain was allowed to start, both the amount of stress relaxed, Delta sigma(t) = sigma(o),-sigma(t), and the magnitude of the stress-relaxation rate,s =[d(Delta sigma)/d ln(t)], increased with the increase in grain size. However, the stress-sensitivity of relaxation rate, ds/d sigma(o), was independent of the grain size. The intrinsic height of the energy barrier, U-o, to the movement of relaxing dislocations was found to be 5.3 eV, which points to dislocation intersection as the rate-controlling process of stress-relaxation. A comparison of the available data for copper and Cu-Zn alloy system over a wide range of solute concentration shows that stress-relaxation response is sensitive to the alloy microstructure, e.g. mode of spatial distribution of solute atoms, dispersion of second-phase particles, etc.
10.1016-j.jallcom.2009.02.074	12	thermodynamic; ternary; phase; data; experimental; equilibria; phase equilibria; liquid; binary; experimental data; calculated; phases; literature; model; calphad	The phase relationships of the Cu-Ti-Sn ternary system at 473 K have been investigated mainly by means of X-ray powder diffraction (XRD), scanning electron microscopy (SEM), optical microscopy (OM) and differential thermal analysis (DTA). The isothermal section consists of 17 single-phase regions, 33 two-phase regions and 17 three-phase regions. The existence of 12 binary compounds and 2 ternary compounds, namely Cu4Ti, Cu3Ti2, Cu4Ti3, CuTi, CuTi2, Cu3Sn, Cu6Sn5, Ti3Sn, Ti2Sn, Ti5Sn3, Ti6Sn5, Ti2Sn3, CuTi5Sn3 and CuTiSn, are confirmed in the Cu-Ti-Sn ternary system at 473 K. No new ternary compound is found. The maximum solid solubility of Cu in Ti6Sn5 was approximately 10 at% Cu.
10.1016-j.jallcom.2009.02.114	4	transformation; martensite; martensitic; phase; shape; beta; memory; shape memory; temperature; temperatures; martensitic transformation; gamma; transformation temperatures; effect; thermal	Subjecting Cu-Zn samples to annealing under dynamical vacuum produces the evaporation of Zn, a process known as dezincification. Here, we study the phase transitions related to dezincification of Cu-48 at% Zn (bcc, Beta phase) single crystalline surfaces with residual stresses due to mechanical polishing. In order to identify different steps in the dezincification process of these deformed samples we apply a combination of in situ optical microscopy and transmission electron microscopy (TEM) observations. The former allows us to control and stop the dezincification process at a specific stage of evolution while the latter allows relating surface features with structure and composition changes. Due to dezincification, the formation of an on average 4H hexagonal phase and the fcc equilibrium phase take place. TEM observations show that the bcc to 4H phase transformation occurs by a mechanism of nucleation and growth . In particular, we show evidence of the mechanism of embryo formation for the first time. During the subsequent growth process, the coalescence of transformed zones defines regions in the micron range which after subsequent prolonged dezincification transform to the final fcc equilibrium structure. These experiments provide an insight on the reason for the formation of the non-equilibrium hexagonal phase during the dezincification of electropolished (non-deformed) samples. The new experimental results evidence the heterogeneous character of the dezincification.
10.1016-j.jallcom.2009.03.078	-1		Cu-6 wt% Fe and Cu-12 wt% Fe microcomposites were prepared by cold drawing. A homogenizing treatment at 950 degrees C for 3 h followed by furnace cooling was carried out before drawing. The microstructure was observed and the tensile strength and electrical resistivity were determined. The original cast or homogenized microstructure develops into the filamentary composite structure in drawing process. The homogenizing treatment promotes the precipitation of secondary Fe particles in the Cu matrix and disperses primary Fe dendrites. Fe precipitates and dispersive Fe dendrites; in the homogenized microstructure result in finer and more uniform composite filaments in the drawn microstructure. The tensile strength and electrical resistivity increase with the increase in drawing strain. The homogenizing treatment increases the strength, especially for the microcomposites at high draw ratios and decreases the resistivity, especially for Cu-6 wt% Fe. The improvements in strength and conductivity as a result of the prior homogenizing treatment can be attributed to the increased interface obstacle and reduced solute scattering in the filamentary structure.
10.1016-j.jallcom.2009.05.020	-1		In the present work, thermodynamic and kinetic calculations were combined to study the glass forming ability of Cu-Zr binary system. Applying thermodynamic association model, the primarily crystallized phase and its corresponding driving force can be determined firstly. Then, the whole Time-Temperature-Transformation (TTT) diagrams basing on homogeneous and heterogeneous nucleation modes have been constructed quantitatively. As for the former case, the critical cooling rate is underestimated by about three orders of magnitude in comparison with the experimental observation. As for the latter case adopting suitable values of catalytic factor f(theta) and potential nuclei N-1, the predictions agree well with the experimental results, and moreover, the nose temperature of TTT diagram is upper-shifted. This has been discussed using a competition of the atomic mobility and the reduced nucleation barrier, as well as its further effect on the nucleation and growth process.
10.1016-j.jallcom.2009.05.023	11	glass; bulk; metallic; bulk metallic; gfa; bmg; glassy; metallic glass; ability; bulk metallic glass; amorphous; addition; crystallization; mm; glass-forming	Effect of the addition of a small amount of Ge on mechanical properties and fracture behavior of Cu50Zr43Al7 (at%) bulk metallic glass were studied. The Cu50Zr43Al7 alloy has a surprising glass-forming ability (GEA), and the glassy rods up to 4 mm in diameter can be formed. Partial addition of Ge causes the crystalline phases precipitate in the glassy matrix Of (Cu50Zr43Al7)(100-x) Ge-x (x = 0, 1, 2) rods with a diameter of 4 mm. In uniaxial compression, Cu50Zr43Al7 bulk metallic glass exhibit high strength of 1692 MPa and very limited plasticity of 0.05%. When Ge increases from 0 to 2 at%, the strength decreases, but plastic strain increases about 2.5%. Fracture surface and shear bands of samples were investigated by scanning electron microscopy (SEM).
10.1016-j.jallcom.2009.05.056	12	thermodynamic; ternary; phase; data; experimental; equilibria; phase equilibria; liquid; binary; experimental data; calculated; phases; literature; model; calphad	The Cu-Sb binary system can be important for various applications, especially for electronic products as a part of lead-free soldering technology. It was found that delta and eta phases have been frequently encountered in the electronic products. However, the two phases have been described as line compounds in the previous thermodynamic modeling, and their compositional homogeneities were not considered. Moreover, the gamma phase has been described as BCC_A2 and this kind of description makes big problem for extension of calculations to some higher order systems. In this study, the thermodynamic properties of the Cu-Sb binary system were modeled and the phase diagram was calculated by the CALPHAD method, using experimental information reported in the literature. The delta phase was described using compound energy model with two sublattices. In this way the compositional homogeneity could be calculated. Good agreement was found between the calculated results and the existing experimental data.
10.1016-j.jallcom.2009.06.129	16	wear; composite; composites; powders; milling; particles; powder; wt; sliding; friction; hardness; matrix; mechanical; surface; properties	Friction and wear behavior of a peak aged Cu-0.65 wt%Cr alloy was investigated. The friction and wear experiments were run under ambient conditions with a pin-on-disk tribometer. Experiments were performed using various applied normal loads and sliding velocities. The tribological behavior of the studied alloy was discussed in terms of friction coefficient, wear loss and wear mechanism. Friction coefficient and wear loss have shown large sensitivity to the applied normal load and the sliding velocity. At the sliding velocity of 0.3 m/s weight loss increased from 6.9 to 51 mg by increasing the normal load from 20 to 40 N. At higher sliding velocity minimum weight loss is achieved at 60 N normal load. So it can be seen that with increasing normal load wear rate decreases due to the formation of a continuous tribofilm which consists of Fe-Cu intermetallic. Varying of friction coefficients in different conditions of normal load and sliding velocity is correlated to the wear behavior. The analysis of worn surfaces by XRD and SEM showed that an increase in normal load and sliding velocity creates an intermetallic wear-induced layer, which modifies the wear behavior of the alloy. The XRD result indicates that new phase of Cu9.9Fe0.1 is generated on worn surfaces of the pin specimens during the wear tests. There is a significant correlation between the micrograph of worn surfaces and the wear rate of specimens.
10.1016-j.jallcom.2009.09.068	16	wear; composite; composites; powders; milling; particles; powder; wt; sliding; friction; hardness; matrix; mechanical; surface; properties	Brass and especially bronze in copper based alloys are widely used as journal bearing material. Pure copper materials are not used as journal bearing material due to their low mechanical and hardness properties. These materials having acceptable tribological and mechanical performance give satisfactory results in journal bearings. In this study, tribological and mechanical properties of journal bearings manufactured from copper based CuSn10 bronze and CuZn30 brass were investigated. Moreover, the effect of alloy elements of Cu, Sn and Zn on tribological and mechanical properties of journal bearings was evaluated. SAE 1050 steel shaft (journal) was used as counter abrader. Wear experiments were carried out at 20 N loads, 1500 rpm for 2.5 h by using radial journal bearing wear test rig.
10.1016-j.jallcom.2009.09.083	16	wear; composite; composites; powders; milling; particles; powder; wt; sliding; friction; hardness; matrix; mechanical; surface; properties	This paper presents a study on the effects of milling speed on the properties of in situ copper-based composite produced by mechanical alloying followed by cold pressing and sintering. A powdered mixture of copper, niobium and graphite with the composition of Cu-30%NbC was milled at various speeds (100, 200, 300 and 400 rpm). The NbC phase started to precipitate in the as-milled powder after 30 h milling at 400 rpm and the formation was completed after sintering at 950 degrees C. Enhancements of NbC phase formation with a reduction in Cu crystallite size were observed with the increase of milling speed. Density, hardness and electrical conductivity of the sintered composite were evaluated. An increase in milling speed resulted in an increase in sintered density and hardness but a reduction of electrical conductivity. The changes in the properties were correlated to the formation of NbC phase and refinement of copper and niobium carbide crystallite size since higher milling speed is associated with higher kinetic energy per hit.
10.1016-j.jallcom.2009.10.056	-1		In order to estimate the temperature rise generated by the extreme shear during high pressure torsion deformation, a simple model based on the one-dimension heat-conduction equation was proposed. Calculations have shown that the average temperature in the sample can slightly exceed the glass transition temperature above a critical strain The experimentally obtained shear dependent microstructure and morphology of an amorphous Cu60Zr30Ti10 alloy are consistent with the calculated temperature profiles
10.1016-j.jallcom.2009.11.026	-1		The effect of solution temperature on martensite transformation temperatures, damping capacity and shape memory effect of a Cu-7.66A1-9.52Mn alloy was investigated by resistivity-temperature method, reversal torsion pendulum method and bend test. The results showed that with increasing temperature, the transformation temperatures and shape memory effect first remarkably increased and then almost remained constant. The damping capacity significantly increased with temperature up to 1098 K and then decreased. The damping capacity was dependent on not only the amount but also the thickness of the martensite plates, while the shape memory effect was mainly determined by the amount of the martensite.
10.1016-j.jallcom.2009.11.072	4	transformation; martensite; martensitic; phase; shape; beta; memory; shape memory; temperature; temperatures; martensitic transformation; gamma; transformation temperatures; effect; thermal	Two internal friction peaks are observed in the Cu-11.9Al-2.5Mn (wt%) shape memory alloy at around 150 and 325 degrees C during heating. The high-temperature peak originates from the phase transition in which martensite transforms to austenite while the low-temperature peak results from the pseudo-first-order phase transition associated with the thinning process of the twins. In the present study the effect of heat treatment on the two internal friction peaks was studied and correlated with the martensite microstructures. It was found that relative high quenching temperature and rapid cooling speed gave rise to both increased ambient damping and low-temperature peak due to the formation of favorable twin structure characterized by coarse twin boundaries and high twin content, indicating that the motion of twin boundaries was the predominant damping mechanism in the martensite state. The high-temperature peak, however, followed a non-monotonous dependence on the quenching temperature and cooling modes. It was proposed that the high-temperature peak depends on the content of martensite and the concentration of the quenched-in vacancies, rather than the twin structures.
10.1016-j.jallcom.2010.02.034	-1		In this paper, elemental Cu-7 wt% Cr powder mixture was mechanically alloyed in order to study the solid solubility extension during the alloying process. By mechanical alloying in a high energy ball mill, a nano-structured and homogeneous Cu-Cr powder was obtained. The effect of toluene as a process control agent (PCA) was investigated. The structural changes were characterised by X-ray diffraction (XRD) technique. The Gibbs free energy change in this system during the formation of solid solution was calculated and shown to be positive, which means that a thermodynamic barrier exist for the formation of this alloy system in solid state. It was found that the additional energy stored in the nano-crystalline Cu-Cr alloy during mechanical alloying process as a result of crystallite size reduction and increased dislocation density, would be high enough to overcome the thermodynamic barrier in the formation of a solid solution.
10.1016-j.jallcom.2010.02.067	-1		We present density functional theory (DFT) calculations results on two representative clusters (Cu7Zr6 and Cu10Zr5) and their interconnections (touching and interpenetrating). The choice of these clusters and their combinations is dictated from previous molecular dynamics (MD) simulations results on the Cu60Zr40 model metallic glass (MG) in which they were found to be the most abundant microstructural units. In addition, aiming in gaining inside on the experimental findings referring to properties improvement upon small Al additions in the CuZr MGs, we performed calculations for the same systems in which Al substitutional atoms were incorporated into the clusters. In all cases the electronic structures were analyzed and the corresponding bonding characteristics were deduced. Moreover, in order to reveal the electronic modifications these systems subsist under mechanical deformation, we performed non-equilibrium calculations by applying tensile solicitations and we deduced the basic alterations that are responsible for the systems' responses. It turns out that Al has elemental bonding preference; its presence in the clusters and in their interconnections alters significantly their electronic structure by introducing new low-energy states, while significant charge transfer occurs upon mechanical deformation. The present results are in line with the available experimental findings and provide inside on the fundamental issues that are related with the improvement of the glass forming ability and of the mechanical properties in the systems that contain small Al additions.
10.1016-j.jallcom.2010.02.124	-1		The structural evolution of nano-scale magnetic particles formed in Co-Fe-Ni alloys on isothermal annealing at 878 K has been investigated by means of transmission electron microscopy (TEM), electron dispersive X-ray spectroscopy (EDS), electron energy-loss spectroscopy (EELS) and field-emission scanning electron microscopy (FE-SEM). Phase decomposition of Cu-Fe-Ni occurred after an as-quenched specimen received a short anneal, and nano-scale magnetic particles were formed randomly in the Cu-rich matrix. A striking feature that two or more nano-scale particles with a cubic shape were aligned linearly along < 1,0,0 > directions was observed, and the trend was more pronounced at later stages of the precipitation. Large numbers of < 1,0,0 > linear chains of precipitates extended in three dimensions in late stages of annealing.
10.1016-j.jallcom.2010.02.140	-1		Cu based bulk metallic glass (BMG) strips were produced by a single pass of powder rolling of the metallic glass (MG) powder canned in a copper container. The effects of the thickness reduction on the consolidation and deformation of BMG alloys after powder rolling were examined. The BMG strips were produced successively by controlling the rolling reduction. Insufficient movement and deformation of MG particles during rolling with a reduction of <= 65% caused incomplete densification. In contrast, the excessive heat generated from the rolling deformation gave rise to the crystallization of the BMG strips leading to the formation of cracks during rolling with a reduction of >= 85%.
10.1016-j.jallcom.2010.02.198	-1		This paper investigated the mechanical and electrical responses of nanostructured Cu-3 wt%Ag alloy as a function of the strain imposed by a combination of equal channel angular pressing and subsequent cold rolling. The influence of cold rolling on the microstructural change was observed to be pronounced, resulting in the occurrence of lamellar band structure. Room-temperature tension tests results revealed that, as the amount of strain increased, the tensile strength of the nanostructured Cu-3 wt%Ag alloy increased while losing its ductility. The electrical conductivity slightly decreased with increasing amount of strain imposed. This phenomenon was mainly attributed to the nano-grained structure together with the non-equilibrium state of the grain boundaries.
10.1016-j.jallcom.2010.03.014	1	shape; memory; shape memory; damping; martensite; martensitic; damping capacity; transformation; capacity; strain; superelasticity; temperature; cu-al-mn; shape memory effect; effect	Equal channel angular pressing (ECAP) was applied to modify the microstructures of Cu-Al-Be-B shape memory alloys (SMAs) The alloy was greatly refined because of the interaction of the large plastic deformation and physicochemical effects With an increase of ECAP passes, the specimens showed a change from plastic fracture to brittle fracture, increased proportion of transgranular fracture, and decreased ultimate strength from 460 MPa to 340 MPa These were caused by the precipitation of the gamma(2)-phase and the disappearance of thermoelastic martensite After appropriate heat treatment, the content of thermoelastic martensites increased, while the grain size remained smaller than that of the as-cast alloy. Further tests showed that the ultimate strength of this alloy improved to 703 MPa and the attenuation of shape recovery ratio was alleviated.
10.1016-j.jallcom.2010.03.048	16	wear; composite; composites; powders; milling; particles; powder; wt; sliding; friction; hardness; matrix; mechanical; surface; properties	In the present study. Cu(Mo)/30Vol.%alpha-Al2O3 nanocomposite was successfully synthesized by a displacement reaction between Al and MoO3 in ball milling of initial Cu, MoO3 and Al powders The evaluation of powders was studied by X-ray diffraction (XRD), transmission electron microscopy (TEM), scanning electron microscopy (SEM), differential thermal analysis (DTA) and measurements of vial temperature. The results showed that mechanochernical reaction between MoO3 and Al took place at the early stage of milling in combustion mode and led to increase of the vial temperature and formation of Al2O3 reinforcements By increasing the milling time. Mo dissolves in copper matrix. Finally after 60 h of milling, the formed nanocomposite contains nanostructured supersaturated Cu(Mo) solid solution matrix, with a homogenous distribution of nanosized Al2O3 and Mo reinforcements Annealing of milled powders at 700 C for 30 min. showed no significant increase in crystallite size of matrix, however partial transformation of alpha-Al2O3 into different polymorphic gamma-Al2O3 was observed Microhardness of this nanocomposite was found to be about 307 HV which is higher than pure Cu (C) 2010 Elsevier B V. All rights reserved
10.1016-j.jallcom.2010.03.207	-1		In this study, the nanoindentation behavior of a Cu-Zr-Al-Ag bulk metallic glass was investigated at various loading rates. It is found that the load-displacement curve of indentation exhibits a significant serration of displacement jumps (pop-ins). The experiment data show that the depths of the pop-in site are a geometric series. The size of pop-ins increases with indentation depth but decreases with loading rate; a larger applied loading rate leads to smaller pop-ins during the indentation process. However, the experimental results indicate that the loading rate has no influence on the depth ratio of pop-in sites. FIB observation and TEM diffraction patterns show that the microstructure of the BMG material remained amorphous irrespective of the presence shear bands.
10.1016-j.jallcom.2010.03.246	-1		This paper studied the influence of Ag micro-alloying on the deformation-processed Cu-7Cr in situ composite, by a comparison of Cu-7Cr and Cu-7Cr-0.07Ag. For both alloys, the as-cast microstructure consisted of a Cu matrix and Cr dendrites: after hot and cold working the microstructure consisted of a Cu matrix containing Cr fibres elongated in the working direction. The as-cast microstructure of the Ag-containing alloy contained finer Cr dendrites. The Ag-containing in situ composite had thinner Cr fibres, higher tensile strength, higher ductility, and slightly higher conductivity. The Cu-7Cr-0.07Ag in situ composite had a good combination of properties: a tensile strength of 772 MPa and a conductivity of 77.3%IACS.
10.1016-j.jallcom.2010.04.098	-1		The induction effects of applied external magnetic field on the morphology, composition and magnetic properties of copper-nickel system grown with hydrothermal method have been investigated in the presence of polyvinyl pyrrolidone (PVP) The products' phases and morphologies are characterized by X-ray diffractometer (XRD) and field emission scanning electronic microscopy (FESEM) Magnetic measurements reveal that the introduction of magnetic field could lead to the enhancement of magnetic parameters, which implies that the magnetic field could exert influences on the nucleation and domain structure of particles Crown Copyright
10.1016-j.jallcom.2010.04.193	2	corrosion; surface; film; electrochemical; films; spectroscopy; layer; current; solution; potential; resistance; composition; x-ray; ions; showed	The present paper reports on a systematic study of the influence of Zn alloying on the structural and optical characteristics of CuZnO thin films. Nanocrystalline CuZnO thin films were prepared on p-type Si (1 0 0) substrates by spin coating from a CuO solution mixed with Zn of 0-8.0 at%. All the prepared samples were annealed in oxygen gas atmosphere at 673 K for 2 h . A detailed characterization of the films doped with zinc was performed by X-ray diffraction (XRD), Fourier transform infrared (FT-IR) spectroscopy, ultraviolet-visible (UV-vis) spectroscopy, photoluminescence (PL) spectroscopy, atomic absorption spectroscopy (AAS), and energy dispersive X-ray spectroscopy (EDS). The structural analyses suggest that Zn successfully occupied the Cu sites and did not change the monoclinic structure of CuO. After 4.0 at% Zn was doped, the crystalline quality and (0 0 2) preferential orientation of the thin film improved. However, when the Zn doping concentration was above 4.0 at%, the crystalline quality and preferential orientation of the thin film weakened in turn. The XRD and FT-IR results showed single phase CuZnO for the lower (at% <= 6.0) Zn concentration, while a secondary phase of ZnO evolved for 8.0 at%. The optical band gap, determined from the absorbance spectra, showed a blue shift with increasing Zn content. The works showed that the structural and optical properties of CuO films doped with Zn can be improved and the 4.0 at% Zn-doped CuO thin films have the best crystallization quality and the strongest emission ability.
10.1016-j.jallcom.2010.04.243	16	wear; composite; composites; powders; milling; particles; powder; wt; sliding; friction; hardness; matrix; mechanical; surface; properties	Copper (Cu), niobium (Nb) and graphite (C) powders were used as starting materials to produce an in-situ Cu-15 vol% NbC composite using mechanical alloying followed by spark plasma sintering (SPS). A mixture of Cu, Nb and C powders was milled in an argon atmosphere for 30 h . Different amounts of ethanol were used to study the effect of the process control agent on the formation of NbC and the consequent properties of the Cu-NbC composite. The results showed that NbC was formed in the copper matrix during ball milling when the powders were milled with 0-2 wt% ethanol, whilst the powder milled with 5 wt% ethanol only exhibited NbC formation after sintering. The as-milled powders were then sintered using SPS at 1000 degrees C, an applied pressure of 100 MPa and soaking duration of 15 min. As a result, the best combination of properties was observed in the sintered Cu-15 vol% NbC composite using a powder milled with 1 wt% ethanol, viz, electrical conductivity of 24% IACS, microhardness of 377 HV and relative density of 97%.
10.1016-j.jallcom.2010.05.077	12	thermodynamic; ternary; phase; data; experimental; equilibria; phase equilibria; liquid; binary; experimental data; calculated; phases; literature; model; calphad	The Cu-Ge binary system was assessed thermodynamically using the CALPHAD method through Thermocalc (R) software package based on the evaluation of all available experimental data from the published literature. The solution phases, including liquid, fcc, hcp and diamond (Ge), were described by the substitutional solution model, of which the excess Gibbs energies were expressed with the Redlich-Kister polynomial. Due to their narrow homogeneity ranges, all intermetallic compounds, epsilon-Cu(0.765)Ge(0.235), theta-Cu(0.735)Ge(0.265) and eta-Cu(0.75)Ge(0.25), were modeled as stoichiometric compounds. A set of self-consistent thermodynamic parameters formulating the Gibbs energies of various phases in the Cu-Ge binary system was obtained finally. A good agreement is achieved between the calculated results and the reported experimental data.
10.1016-j.jallcom.2010.05.166	-1		Cu-0.4 wt%Cr-0.12 wt%Zr-0.02 wt%Si-0.05 wt%Mg was prepared by casting, quenching, aging and cold drawing. The microstructure was studied by electron microscope and X-ray diffraction. Vickers hardness was measured for the alloy after the annealing treatment at different temperatures covering a wide temperature range from room temperature to 700 degrees C. The ribbonlike structure is replaced by gross equiaxed grains. The crystal orientation is gradually approaching the full annealed specimen and the hardness difference between longitudinal and transverse directions vanishes by recovery and recrystallization. The thermal analysis was carried out and the stored energy was calculated. The release of stored energy and the reduction of resistivity are primarily due to the decrease of dislocation density. The main strengthening effect is attributed to dislocation mechanism.
10.1016-j.jallcom.2010.06.023	-1		Minor M (M = Fe, Mn, Cr) additions are widely added to enhance the corrosion resistance of commercial cupronickel alloys. The present paper aims at optimizing the amounts of M in Cu-70(Ni,Fe,Mn,Cr)(30) (at%) alloys using a cluster-plus-glue-atom model for stable solid solutions. By this model, it assumed that 1 M atom and 12 Ni atoms formed an M-centered and Ni-surrounded cube-octahedron cluster and the isolated M1Ni12 clusters are embedded in a Cu matrix, conforming to a cluster formula [M1Ni12]Cu-30.3 = [Mu(1/13)Ni(12/13)](30)Cu-70. A structure of this kind satisfies ideally the nearest neighbor requirement, i.e. only M-Ni and Ni-Cu neighbors are allowed and the unfavorable Cu-M pairs are avoided, and hence it describes a stable solid solution structure with good thermal stability. Electrochemical corrosion measurements indicated that [(Fe0.6Mn0.25Cr0.15)(1)Ni-12]Cu-30.3 had the best corrosion resistance in 3.5% NaCl aqueous solution.
10.1016-j.jallcom.2010.06.063	-1		Effect of cryogenic treatment (CT) on microstructure and mechanical properties of the Cu-based bulk metallic glasses matrix composite (Cu46Zr46Al8) was investigated. CT brought about the refinement of the primary CuZr phase, the formation of the martensite phase accompanying with the morphology modification of the CuZr precipitates, contributing to the improvement in the microhardness and the compression fracture strength . The size of the CuZr crystalline phase was reduced from about 3 mu m to 2 mu m and the morphology of the CuZr precipitate was transformed from the rotundity to the short rod-shape. The compression fracture strength and the microhardness of the as-cast Cu46Zr46Al8 composite were 1340 MPa and 512 HV respectively, while they were 1759 MPa and 574 HV respectively after CT. Furthermore, CT accelerated the fracture morphology transformation from the ductile to the brittle. The possible mechanisms involved in microstructural modification and strength as well as microhardness improvement were discussed. (C) 2010 Published by Elsevier B.V.
10.1016-j.jallcom.2010.06.150	16	wear; composite; composites; powders; milling; particles; powder; wt; sliding; friction; hardness; matrix; mechanical; surface; properties	A Cu-NbC composite with high electrical conductivity and high microhardness was synthesized by mechanical alloying and densified using spark plasma sintering (SPS). Mixtures of Cu-NbC powders corresponding to volume fractions of 1, 5, 15 and 25 vol% NbC were milled in a high energy planetary mill under argon atmosphere for 30 h using ethanol as process control agent. The Cu-NbC as-milled powder was sintered using spark plasma sintering temperatures between 900 and 1000 C. X-ray diffraction investigation showed that NbC started to form in the copper matrix during ball milling and the reaction between Nb and C was completed after 10 min of SPS sintering. Electrical conductivity and density of the Cu-15 vol% NbC composite increased with increasing sintering temperature. The results showed the superior properties of SPS-prepared Cu-NbC composite: electrical conductivity is almost 4 times higher and microhardness is 3.5 times higher than with normal sintering. A highest density of 98% and electrical conductivity of 45.6% IACS were obtained in the Cu-1 vol% NbC composite. The highest microhardness of 452.9 HV was achieved in the Cu-25 vol% NbC composite.
10.1016-j.jallcom.2010.07.024	-1		Cu/Co multilayers with periodicity of 4-40 nm were prepared by electron beam evaporation deposition. Microstructure and room temperature creep behavior were investigated by X-ray diffraction, transmission electron microscopy and nanoindentation test. The results show that superlattice structure forms with decreasing periodicity and coherent interfaces come into being at low periodicity of 4 nm. Size dependence of the creep behavior is observed and power-law creep parameters including stress exponent and size sensitivity index are calculated by dimension analysis. A dislocation model for predicting the steady-state deformation of multilayers with semi-coherent interfaces is presented. Nanoscale effects are explained by dislocation generation and annihilation mechanisms involving single dislocations slip in confined layers and dislocations climb at the interfaces, respectively. Model predictions agree well with experimental observation.
10.1016-j.jallcom.2010.08.063	-1		Ternary copper-based composites consisting of Cu, 8 wt% Fe and 0.1-6 wt% Ag were prepared by inductive melting and casting. The effect of Ag addition on the as-cast microstructure was investigated using optical microscopy (OM) and scanning electron microscopy (SEM). The results show that the primary Fe dendrites in the as-cast microstructure are refined significantly with the presence of Ag. Contact angle between Cu-Ag alloy and gamma-Fe was measured using sessile drop technique to investigate the refinement mechanism of the primary Fe dendrites. In addition, the effect of Ag addition on the dissolution of Fe atoms in the Cu matrix at high temperature was investigated by means of energy dispersive X-ray spectroscopy (EDS). The results show that the presence of Ag inhibits the solubility of Fe in the Cu matrix at high temperature. Crown Copyright
10.1016-j.jallcom.2010.09.004	-1		A spinel CuIr2S4 exhibits a temperature-induced metal-insulator (M-I) transition at around 226 K. Nonmagnetic substitution effect on the M-I transition, TM-I, in Cu(Ir1-xMx)(2)S-4 (M = Sn, Hf) has been studied on the focus of the rather low composition region of x. Magnetic property of Cu(Ir1-xMx)(2)S-4 (M = Sn, Hf) has been examined experimentally. The TM-I decreases with increasing x and the temperature hysteresis becomes unclear within the experimental errors. The step anomaly in the magnetic susceptibility smears out and the TM-I becomes ill defined around x = 0.20 in Cu(Ir1-xSnx)(2)S-4, and x = 0.10 in Cu(Ir1-xHfx)(2)S-4, respectively. These substitutions play an important role in decoupling the spin-dimerization of Ir4+-Ir4+ in CuIr2S4, and lead the destruction of the metal-insulator transition.
10.1016-j.jallcom.2010.10.170	-1		Cu-Zr-Ti powders were deposited onto Cu plates by thermal spray. Upon impact onto the substrate, the particles spread out and bond well to the substrate, yielding a well adhered surface layer. The coatings then were subjected to severe plastic deformation using surface mechanical attrition treatment in a high energy SPEX 8000 shaker mill by replacing the end cap of the milling vial with the coated targets. It is demonstrated that different mechanical treatments influence the microstructural and mechanical behavior of the Cu-Zr-Ti coating, moreover, a partial solid state amorphization takes place. Roughening of the interface between target and coating ensures strong bonding while the free surface is hard and smooth . Experiments were carried out using X-ray diffraction, scanning electron microscopy, energy dispersive X-ray analysis and hardness measurements.
10.1016-j.jallcom.2010.11.157	-1		Cellular CuAlMn shape memory alloys with open-cell or closed-cell structure have been manufactured successfully by sintering-evaporation process. This process consisted of mixing CuAlMn and NaCl powders, hot pressing and final high-temperature sintering to evaporate the filler material of NaCl powders. NaCl was eliminated completely during vacuum sintering, and strong metallurgical bonding in the cell walls was achieved. The pores' structural parameter (pore size, shape, and direction) and porosity (25-70%) have been controlled effectively. The compressing deformation behavior and phase transformation behavior of the cellular CuAlMn shape memory alloy has been investigated. It was found that the maximum stress of the cellular CuAlMn shape memory alloys increased with the decrease in porosity, and the energy absorption per unit volume approached the maximum value of 35.81 MJ/m(3) (the compression direction parallel to the cross-section) and 25.71 MJ/m(3) (the compression direction perpendicular to the cross-section) as the porosity of the alloys was 60% and the pore size was between 355 and 800 rim.
10.1016-j.jallcom.2010.12.054	11	glass; bulk; metallic; bulk metallic; gfa; bmg; glassy; metallic glass; ability; bulk metallic glass; amorphous; addition; crystallization; mm; glass-forming	Samples of (Cu(46)Zr(46)Al(8))(100-x)Z(x) metallic glass forming alloys with diameters 2-6mm were prepared by injection casting. The effect of minor amounts of elements Z = Gd, Co and Re with positive enthalpy of mixing within the Gd-Zr, Cu-Co and Cu-Re terminal systems was compared. The addition of Gd up to x = 2 slightly enhances the glass forming ability, Co reduces the critical diameter of bulk metallic glass formation, whereas even for small fractions of Re bulk samples were crystalline, but only amorphous splats can be prepared. Both Gd and Co diminish the crystallization temperature T(x) with respect to the Cu(46)Zr(46)Al(8) master alloy, but in Re-bearing splats T(x) is increased. Alloying with optimum amounts of Gd and Co up to x = 2 leads to plastic deformability of rods, 2 and 3mm in diameter, in comparison with the brittle Cu(46)Zr(46)Al(8) bulk metallic glass.
10.1016-j.jallcom.2011.01.076	-1		The oxidation behavior of Cu42Zr42Al8Ag8 metallic glass ribbons at 633-693K was investigated. The oxidation kinetics followed initially a parabolic rate law but change to a linear one after some time. Mushroom shaped silver crystals were observed on the surface of the oxide layer of the sample oxidized at 663K and their formation seemed to accelerate the overall oxidation. The formation of the 'silver mushrooms' was attributed to the extrusion of silver segregated out during oxidation through weak points in the surface oxide scale. The rounded cap was thought to form due to surface tension or residual stress arising from the extrusion process. Such surface morphology is expected to be beneficial for the metallic glasses as biomaterials.
10.1016-j.jallcom.2011.01.127	-1		Cold drawing was conducted at room temperature to impose high strain on Cu-0.4 wt%Cr-0.12 wt%Zr-0.02 wt%Si-0.05 wt%Mg. The microstructure was studied by X-ray diffraction and transmission electron microscope. The thermal analysis was carried out for the alloy at different draw ratios and then the stored energy was calculated to estimate the dislocation density and the flow stress. Results indicate that the microstrain gradually increases and the (111) texture is formed with the draw ratio rising. Meanwhile, the stored energy also increases with the draw ratio rising and a peak is reached with draw ratio of 6.7. The release of stored energy is primarily due to the decrease of dislocation density. The flow stress estimated from the stored energy has a similar variation trend with the measured data with a stress difference similar to 20 to 120 MPa. The main strengthening effect is attributed to dislocation mechanism. Crown Copyright
10.1016-j.jallcom.2011.03.091	-1		In the current investigation Cu-30Ni alloy was successfully laser deposited on a rolled C71500 plate substrate by Direct Metal Deposition technology. The microstructural investigation of the clad was performed using optical and scanning electron microscopy. The phase and crystal structure analysis was performed using X-ray diffraction technique and transmission electron microscopy. The microstructure consisted of columnar and equiaxed dendrites with face centered cubic crystal structure. The dendrites grew epitaxially from the substrate and layer and bead boundaries. Dendrites' growth direction (001) and growth angle 60 degrees. was maintained in each layer. The average primary dendritic arm spacing at the bottom part of the layers was about 7.5 mu m and average secondary dendritic arm spacing in the upper part of the layer varied between 2 mu m and 4.5 mu m. The lattice parameter of the identified phase was found to be longer than that reported in literature. The reported lattice parameters in literature are however from samples processed under equilibrium conditions. The microhardness of the clad was found to be less than the substrate but very consistent along the clad. Cu-30Ni clad specimen showed higher ultimate tensile strength but lower yield strength and percentage elongation as compared to the C71500 substrate. DMD Cu-30Ni clad/C71500 substrate specimen showed the worst mechanical properties. The corrosion resistance of the specimens was found to decrease in the order DMD Cu-30Ni clad, half-and-half DMD Cu-30Ni clad-C71500 substrate, and C71500 substrate.
10.1016-j.jallcom.2011.03.150	-1		Thin film combinatorial sputter deposited Cu6Sn5 + C alloys were prepared and found to be amorphous and/or nanostructured upon removal from the sample preparation chamber. Samples having approximate compositions (Cu6Sn5)(1-x)C-x with 0.16 < x < 0.26 have been stored at room temperature and investigated over the course of about one year using X-ray diffraction (XRD). Simple models were employed to analyze the observed changes in the XRD patterns. Relatively sharp (nanocrystalline) components having Bragg angles corresponding to hexagonal Cu6Sn5 grew in intensity at the expense of broader (amorphous) components as a function of time. The grain size of the nanocrystalline components was approximately time independent, but depended on the amount of carbon present. The logarithm of the recrystallization time and the activation energy for crystallization appeared to be linearly dependent on the carbon content for the composition range that has been studied, as inferred from the Avrami-Johnson-Mehl equation. XRD patterns of samples with x > 0.26 appear to be relatively unchanged after a period of storage at room temperature for one year.
10.1016-j.jallcom.2011.04.017	-1		The microstructures of the surfaces and cross sections of Cu-Cr contact alloys were analyzed after the vacuum breakdown was repeated for 100 times. The results reveal that the liquid phase separation was involved in the microstructure evolution of the alloys during the breakdown. The Cr-rich phase from the liquid separation featured the morphology of spherical-and sheeted-shaped particles. The sizes of the Cr spheres ranged from several nanometers to hundreds of nanometers, and were not strongly dependent on the compositions of the alloys. The large Cr-rich droplets could be elongated and swirled due to the liquid flow, resulting in the formation of the Cr phase with sheeted-shaped particles. The fractions of Cr sheets increased with the increasing of the Cr contents; however, their sizes decreased significantly, compared with those of their parent alloys.
10.1016-j.jallcom.2011.06.030	-1		Cu-6 wt% Fe and Cu-12 wt% Fe filamentary composites were prepared by casting and cold drawing. And a different heat treatment of quenching and aging or homogenizing was introduced before cold drawing process, respectively. The microstructure was observed and the tensile strength measured for the composites at different drawing strains. The quenching and aging or homogenizing prior to drawing deformation refine the as-cast microstructure and result in the increase in interface density in the drawn microstructure. The drawn alloys with the homogenizing treatment show smaller filament spacing than those with the quenching and aging treatment because homogenizing results in smaller and more dispersive primary Fe dendrites before drawing deformation. The heat treatments can improve the strength of the composites by increasing precipitation strengthening and interface strengthening levels. With the reduction in filament spacing during drawing deformation, the strength of the alloys with smaller initial size of Fe dendrites increases more obviously. Crown Copyright
10.1016-j.jallcom.2011.07.077	0	solidification; phase; magnetic; magnetic field; undercooling; field; liquid; separation; peritectic; immiscible; cu-; dendrite; phase separation; microstructure; primary	The dependence of microstructure on undercooling for Cu50Co50 immiscible alloy and the relations between dendrite fragmentation and liquid phase separation were studied by melt-fluxing in combination with cyclic superheating. It is shown that homogeneous dispersed structure can be obtained by dendrite fragmentation because of the increased solute content in primary dendrite, which is advantageous for strengthening dendrite remelting effect and thermal plateau time following recalescence. As for the sample after liquid separation, typical dual-layer structure forms, while dendrite fragmentation still exists and its extent, volume fraction are influenced by the solute contents of two immiscible layers. Quantitative thermodynamic calculation was further performed to support the experimental results.
10.1016-j.jallcom.2011.07.106	12	thermodynamic; ternary; phase; data; experimental; equilibria; phase equilibria; liquid; binary; experimental data; calculated; phases; literature; model; calphad	The phase equilibria at the isothermal section of the Cu-Ni-Si system at 700 degrees C were experimentally investigated. Thirty Cu-Ni-Si alloys were prepared by arc melting and annealed at 700 degrees C for 30 or 80 days, and examined with optical microscopy, X-ray diffraction, scanning electron microscopy with energy dispersive X-ray spectroscopy and electron probe microanalysis. Twelve three-phase regions were determined. The existence of the ternary compound tau(1)-Cu(56.8-63)Ni(10.4-16.1)Si(26.6-27.3) reported in literature was confirmed and a new compound tau(2)-Cu(45.8)Ni(25)Si(29.2) with nearly no homogeneity range was observed. The theta-Ni(2)Si compound, which exists above 820 degrees C in the binary Ni-Si system, was found to be stable at 700 degrees C and the composition range of Cu is 12.7-20.6 at% Cu. The ternary solubilities of binary compounds were measured and noticeably the Cu(56)Si(11) compound can dissolve Ni up to 21.9 at%.
10.1016-j.jallcom.2011.11.079	6	grain; deformation; strain; strength; dislocation; cu-; tensile; size; ecap; grain size; sfe; ductility; hardening; high; stress	This study evaluated the grain refinement and mechanical properties of Cu-40%Zn brass processed by equal channel angular pressing (ECAP). The samples were repeatedly pressed to strains as high as 4 at a temperature of 250 degrees C using route C. Recrystallization heat-treatment was carried out at 350 degrees C for 20 min. To evaluate the grain boundary character distributions and mechanical properties of ECAP materials, electron backscattered diffraction, Vickers microhardness, and tensile tests were used. Increased passes in ECAP led to notable grain refinement, from 13 mu m in the initial sample (350 degrees C/180 min heat-treated material) to 300 nm after 4 passes. The post-heat-treated material after ECAP also sustained refined grain size (2.4 mu m in the alpha phase and 4 mu m in the beta' phase) than that of initial state, which resulted in an increase in tensile strength with no decrease in elongation. Furthermore, coincidence site lattice boundaries derived from annealing twins were more developed than those of the initial material. This paper discusses the enhancement of mechanical properties in terms of grain boundary character distributions development.
10.1016-j.jallcom.2011.11.130	12	thermodynamic; ternary; phase; data; experimental; equilibria; phase equilibria; liquid; binary; experimental data; calculated; phases; literature; model; calphad	Ternary Cu-Sb-Zn system has been thermodynamically assessed by using CALPHAD method and experimentally by DSC and SEM-EDS methods. The liquidus projection, invariant equilibria, several vertical sections and isothermal sections at 450 degrees C and 25 degrees C were predicted using COST 531 Thermodynamic Database. Phase transition temperatures of alloys along three predicted vertical sections of the Cu-Sb-Zn ternary system with molar ratios Cu:Zn = 1: 3, Cu: Zn = 1 and Sb:Zn = 1, were determined by DSC analysis. Predicted isothermal sections at 450 degrees C and 25 degrees C were compared with the results of the SEM-EDS analysis. The calculated values were found to be in a good agreement with the experimentally obtained values and literature data.
10.1016-j.jallcom.2012.02.145	-1		Cu-Al-Ni-based shape memory material was elaborated by spark plasma sintering method from the micron and submicron sized particles prepared by spark-erosion method in liquid argon from preliminary melted master alloy with the composition of Cu-13.01Al-3.91Ni-0.37Ti-0.24Cr wt%. The effects of processing parameters, mainly temperature of sintering and sintering time on the martensitic transformation and microstructure of the sintered compacts were investigated. Both martensitic phases (18R and 2H) available for Cu-Al-Ni alloy of such composition as well as gamma and alpha phases were found in sintered samples. Their amounts depend on the temperature of sintering and seem to be strongly affecting the Ms point. Although the powder has already sintered at 390 degrees C the best quality of samples were found for samples sintered at 650-700 degrees C.
10.1016-j.jallcom.2012.04.111	-1		This paper describes the effect of Sn addition on the thermal and structural behaviour of (Cu60Zr25 Ti-15)(100) Sn-x(x) (x = 0, 1, 2, 3 and 4) alloys. Expansion of the amorphous phase causing larger inter-atomic distances is observed with increasing Sn content. The glass transition temperature (T-g) and the onset of the first crystallization temperature (T-x) shifts to higher temperatures for alloys with increased Sn content. These, together with the increase in the activation energy of the 1st crystallization peak obtained from Kissinger analysis indicate the enhanced thermal stability of the alloys with increasing Sn content. Sn addition also widened super cooled liquid region of the alloys. TEM and XRD studies show nucleation of nano crystals associated with the first exothermic events. The size of the nano crystals increased from 6 to 20 nm when the Sn content varied from 0 to 4 at%. A plausible explanation is invoked for the increase in the size of nano crystals with increase in Sn content. Irrespective of the Sn content all the alloys transform to Cu51Zr14 crystalline phase after the second exothermic peak. Glass transition temperature of the alloys varies with heating rate following Lasocka's relationship; using the relationship, the theoretical limits of the low temperature range of the glass transformation region, i.e. for the heating rate beta = 1, of these alloys are also estimated.
10.1016-j.jallcom.2012.05.108	-1		Cu-Ni-P alloy with unique microstructures were deposited by electroless plating. The effect of deposition parameters on the morphology, crystallographic texture and hydrophobic property of the as-prepared alloy was investigated. SEM observation reveals that the morphology of Cu-Ni-P deposits can be controlled by adjusting Ni2+ concentration, temperature and pH value. Cone structure with dimensions of about 5 mu m in height and 0.5 mu m in root diameter could be obtained by optimum parameters of 0.0024 M Ni2+, 70 degrees C, pH 9, 0.05 M sodium citrate and 50 ppm PEG10000 (or 4000). XRD results show that Cu-Ni-P cone structure is well-crystallized and exhibits strong (111) texture. When the concentration of Ni2+ and OH increases, the surface of Cu-Ni-P coating is comparatively smooth and shows a preferred orientation of (220). Static contact angles were measured to investigate the surface's wettability. The results reveal that Cu-Ni-P alloy with dense cone structure is hydrophobic with maximum static contact angle of 140 degrees, while that of flat Cu-Ni-P alloy is 93 degrees. Crown Copyright
10.1016-j.jallcom.2012.06.038	0	solidification; phase; magnetic; magnetic field; undercooling; field; liquid; separation; peritectic; immiscible; cu-; dendrite; phase separation; microstructure; primary	A huge triple phase region of the nonfaceted-nonfaceted peritectic reaction within a large temperature region (around 8 K) was obtained in directionally solidified Cu-Ge alloys, which provides a convincing experimental evidence for studying the morphology of peritectic reaction trijunction region. The huge non-isothermal triple phase region suggests that the peritectic reaction occurs in a composition range, which is different from the classic isothermal model with a fixed composition (Liquid + solid solution alpha(CuGe12) -> solid solution zeta(CuGe12.8)). The geometrical morphology of triple junction region shows that the primary a phase remelted ahead of the growing peritectic phase and resolidified near the triple phase junction. And some new characteristics of the peritectic reaction were also observed and systematically analyzed. The results demonstrate that the peritectic reaction during directional solidification occurs in the style: Liquid + remelted alpha(CuGe(12 similar to 12-x)) -> zeta(CuGe(12.8-12.8+ y)) + resolidified alpha(CuGe12). The x and y depend on growth conditions and alloy composition. The remelting and resolidification phenomenon were discussed in detail, in which the effects of temperature gradient, mechanical equilibrium and solute diffusion were considered. Orientation relationship between the phases was studied by the electron back-scatter diffraction (EBSD) technology.
10.1016-j.jallcom.2012.07.150	-1		The effect of electropulsing treatment (EPT) on properties, microstructures and texture of the cold-rolled Cu strips is investigated by electron back scattered diffraction (EBSD). The results show that the elongation of Cu strips increases while the Vickers hardness and electrical resistivity drop with the increase of the frequency of electropulsing excluding 600 Hz. The grain size increased with increasing the frequency of electropulsing. The frequency of coincident site lattice (CSL) and twin reach the maximum using the EPT of 400 Hz. In addition, the change of microstructure induced by EPT strengthens P{011}< 12 (2) over bar > orientation and weakens S{123}< 63 (4) over bar > and Bs{110}< 1 (1) over bar2 > texture component content. The twin formation and crystallization mechanism of the cold deformed Cu under electropulsing are proposed.
10.1016-j.jallcom.2012.11.026	4	transformation; martensite; martensitic; phase; shape; beta; memory; shape memory; temperature; temperatures; martensitic transformation; gamma; transformation temperatures; effect; thermal	The activation energy of diffusional creep in copper-iron solid solutions was studied. Experiments were performed on foil samples in an atmosphere of dry hydrogen in a temperature range from about 1170-1340 K. The foils had a thickness of 1.8 x 10(-5) m and a length of about 0.15 m. The stress range was from 0 to 300 kPa. The method of the measurements was developed in our previous work and it was based on measuring the time dependence of stress on a sample. The viscosity of the solid solutions was higher than that for pure copper. It was shown that there is a gap on temperature dependences of viscosity. The temperature of the gap was about 1295 K. Our previous experiments on the Cu-Co system showed the same feature in the activation energies. As previously shown, two processes are required for describing the diffusional creep. They are the volume diffusion and generation/annihilation of the vacancies. The processes occur in sequence. We assume that only second type processes could lead to the appearance of the gap on the temperature dependence of viscosity in solid solutions.
10.1016-j.jallcom.2012.12.043	16	wear; composite; composites; powders; milling; particles; powder; wt; sliding; friction; hardness; matrix; mechanical; surface; properties	The mechanical alloying process is used to produce nano-structured solid solution alloys, which may be further strengthened by the age-hardening process. Milling time is an important parameter during mechanical alloying. In the present research, the optimum milling time for the production of Cu-6 wt% Zr alloy was to be determined. Cu and Zr powder mixtures were milled in a planetary ball mill for different milling times. As milled powder mixtures were investigated by SEM and XRD. Average particle sizes, lattice parameter and average crystal size were determined at different milling times. As milled powder mixtures were subsequently isothermally annealed at different temperatures and their microhardness was measured. The results showed that during milling, average particle size initially increased to a maximum value and decreased at longer times, while average crystal size continuously decreased with milling time. Lattice parameter increased with milling time. The maximum hardness value was obtained after 48 h of milling and annealed at 600 degrees C. Longer milling times did not improve hardness of the material. Crown Copyright
10.1016-j.jallcom.2012.12.154	-1		Morphology, orientation and diffraction patterns of delta-Ni2Si precipitates in a Cu-Ni-Si alloy are investigated by TEM and HREM. Many disk-shaped nanosized delta-Ni2Si precipitates are uniformly distributed in Cu-1.5 wt% Ni-0.34 wt% Si alloy in an over-aging condition. The delta-Ni2Si precipitates preserve an orthogonal structure with a = 0.708 +/- 0.005 nm, b = 0.504 +/- 0.005 nm, and c = 0.364 +/- 0.005 nm. The orientation relationships of six variants of delta-Ni2Si precipitates with Cu-matrix can be determined as (100)p parallel to{001}Cu, [100]p parallel to < 110 > Cu and [010]p parallel to < 110 > Cu. Two typical diffraction pattern models under [001](Cu) and [111](Cu) zone axis are simulated according to diffraction effects of multiple variants, secondary diffraction and the size of particles, which coincide with the experimental results perfectly.
10.1016-j.jallcom.2013.01.136	2	corrosion; surface; film; electrochemical; films; spectroscopy; layer; current; solution; potential; resistance; composition; x-ray; ions; showed	In this paper, an attempt had been made to prepare a Cu-Ni-Fe alloy coating for improving the corrosion resistance of the low-carbon steel. The surface heat treatment of coated low-carbon steel was performed at 1000 degrees C for 3 h under hydrogen atmosphere. The structure and microstructure of coatings was separately analyzed by X-ray diffraction (XRD) and scanning electron microscope (SEM). The corrosion resistance of the samples was evaluated by potentiodynamic polarization (Tafel) and electrochemical impedance spectroscopy (EIS). Results indicated that a compact alloy coating was formed on the surface of low-carbon steel and the Ni content had a prodigious impact to the microstructure, composition and structure of Cu-Ni-Fe alloy coating. Apart from that, significant improvements in corrosion resistance were achieved by using the Cu-Ni-Fe alloy coating, which constituting of homogeneous c-phases. Crown Copyright
10.1016-j.jallcom.2013.02.011	12	thermodynamic; ternary; phase; data; experimental; equilibria; phase equilibria; liquid; binary; experimental data; calculated; phases; literature; model; calphad	Two solid-solid diffusion couples and 29 key samples have been used to construct the isothermal section of the Cu-Ni-Y system at 700 degrees C. Phase relations and ternary solubility of the binary compounds have been determined using scanning electron microscopy (SEM), wave dispersive X-ray spectrometer (WDS) and X-ray diffraction (XRD) analysis. The isothermal section at 700 degrees C consists of two single-phase region, 21 two-phase regions and 10 three-phase regions. Two extended solid solutions, between CuY*-NiY and Cu4Y-Ni4Y have been determined. The maximum solubility of Ni in Cu2Y, Cu7Y2 and Cu6Y has been found to be about 28, 7.5 and 3.9 at% Ni, respectively. The solubility of Cu in NiY3, Ni2Y, Ni3Y, Ni7Y2, Ni5Y and Ni17Y2 is about 12.04, 9.67, 25, 3.08, 75 and 37 at%. Cu, respectively. The solubility of Y in fcc (Cu, Ni) phase is about 0.6 at%.
10.1016-j.jallcom.2013.07.017	-1		Microstructure evolution of copper strips with gradient temperature between two electrodes in electro-pulsing treatment is investigated. The cold-rolled copper strips develop recovery and recrystallization between the two electrodes. The gradient temperature caused by the movement of strips in the treatment process results in the evolution of microstructure. The larger temperature gradient distribution caused by the electropulsing treatment with higher frequency, the larger microstructure evolution the copper strips have, indicating the temperature plays an important role in electropulsing treatment.
10.1016-j.jallcom.2013.07.144	-1		A nanoporous copper structure was fabricated from amorphous binary TixCu100-x (x = 40, 50 and 60 at%) alloys in hydrofluoric acid solutions under a free corrosion condition. A bi-continuous nanoporous structure has a pore size of 25-75 nm and a ligament size of 46-79 nm in 0.03 M HF solution. In 0.13 M HF solution, a pore size of 85-380 nm and a ligament size of 80-338 nm were obtained. The dealloying process is thermal-activated and obeys the Arrhenius law. The surface diffusivity decreases with temperature and concentrations of dealloying solutions. The values of the activation energy of copper adatoms are estimated to be 40.3-78.1 kJ mol(-1), which depend not only on the alloy composition but also on the dealloying electrolyte composition.
10.1016-j.jallcom.2013.07.190	-1		We have investigated the formation of Cu-based amorphous alloy film in Cu-Hf-Al ternary system and the effect of annealing temperature on the mechanical, electrical and electrochemical properties. The films with a composition of Cu72.4Hf18.4Al9.2 were prepared using a DC magnetron sputtering method. We found that the glass transition temperature T-g of the Cu-Hf-Al amorphous film is around 550 degrees C. Upon annealing at temperatures above T-g, the films displayed (partial) crystallization and remarkable changes in mechanical properties and electrical resistance. The Cu-Hf-Al amorphous thin film exhibited high Young's modulus of 127.1 GPa and hardness of 7.2 GPa, and has a strong passivation ability and high corrosion resistance in H+ or Na+ environments.
10.1016-j.jallcom.2013.11.018	-1		First-principle calculations have been performed to investigate the structural, mechanical, thermodynamic and electronic properties of eight binary Cu-Zr intermetallic compounds. The results indicated that with increasing Zr concentration, the mass density decreases monotonously. All Cu-Zr intermetallic compounds considered here are mechanically stable structures, and they are ductile materials. Among the eight binary Cu-Zr intermetallic compounds, CuZr is the most ductile phase. Furthermore, the heats of formation of the Cu-Zr intermetallic compounds are negative. Furthermore, CuZr2 is a semiconductor with indirect band gap of 0.227 eV, while the other seven Cu-Zr intermetallic compounds considered here are conductors.
10.1016-j.jallcom.2013.11.136	-1		The growth mechanism of duplex structural Cu-2(In,Sn) compound formed between eutectic SnIn solder and single crystalline Cu during reflowing and solid-state aging were systematically investigated using a top-view technique. The fine-grain Cu-2(In,Sn) had a granular morphology and distributed homogeneously without any growth orientation, while textured coarse-grain Cu-2(In,Sn) displayed preferential growth on different Cu surface planes. It was observed that on (100) or (111) single crystalline Cu substrates, the coarse-grain Cu-2(In,Sn) compound had regular and elongated shuttle-type morphology along two perpendicular (90 degrees) or three intersecting (120)< 011 >(Cu) directions, respectively. But on (102)Cu surface the grains grew like elongated stripes along only one < 010 >(Cu) direction. Electron beam backscattered diffraction (EBSD) revealed the growth orientation relationships between them, which are [0001](Cu2(In,Sn))//< 011 >(Cu) on (100)Cu and (111)Cu, and [1-100](Cu2(In,Sn))//< 010 >(Cu) on (102)Cu surface. These orientation relationships enable the minimum misfit (2.3-2.9%) of the array of Cu atoms between coarse-grain Cu-2(In,Sn) compound and single crystalline Cu substrate.
10.1016-j.jallcom.2013.11.232	-1		We have addressed a new study by mechanical alloying on the nominally immiscible Cu50Fe50 system with the aim of relating the solid state transformation process, with formation of a disordered unstable solid solution having the face centered cubic habit, to parameters reflecting the impulsive, discontinuous nature of the process. The milling set-up, tools and powder were adjusted in order to ensure completely anelastic hits. Phase analysis, structure and microstructure parameters of such powder system have been followed accurately in the course of the kinetics by X-ray Diffraction using the Rietveld method. The experimental kinetics data points of the amount of transformed solid solution show a typical sigmoidal behavior. It was assumed that dissolution only occurs in the volumes of material that have undergone the necessary critical loading conditions, which is accounted by a discrete series expansion. The mass fraction effectively processed at each collision can be regarded as an apparent rate constant for the microstructural refinement and phase transformation processes. Analysis of model curves fitting the experimental data suggests that it takes up an average of 6 impacts of coupled powder particles to drive the system to the new unstable nano-crystalline state.
10.1016-j.jallcom.2013.12.057	-1		The present work investigated microstructural stability and its concurrent effect on mechanical and electrical properties of hot-rolled Cu-8Cr-4Nb alloy samples at high temperatures (600, 800 and 1000 degrees C) for holding durations up to 50 h . The hot-rolled samples were prepared from the near-theoretical-density hot-pressed alloy, which was made from gas-atomized powders. The hot-rolled alloy showed excellent retention of grain size due to pining of the grain boundaries, induced by the fine and homogeneously distributed stable Cr2Nb dispersoids. The yield strength and ultimate tensile strength of the samples showed no appreciable change at 600 degrees C and 800 degrees C even after 50 h, whereas, YS and UTS dropped slightly on exposure of the sample to 1000 degrees C for 50 h due to grain growth and coarsening of precipitates. The electrical conductivity of the samples remained almost unchanged with a slight improvement with prolonged exposure at higher temperatures.
10.1016-j.jallcom.2013.12.067	-1		Developments in the synthesis of nanostructured materials have expanded the need for appropriate characterization methods. The aim of this work is to apply new X-ray diffraction analysis methods for simultaneous investigation of various microstructural characteristics. For this purpose, the structure of mechanically alloyed Cu-Fe system with three compositions of 30 wt%, 50% and 70% of iron was studied. By applying the modified Williamson-Hall method, the type of dislocations in the FCC phase is distinguished. Afterwards by modification of previous XRD analysis methods, the proportion of edge/screw dislocations was characterized. Moreover, the outer cut-off radius, the density and energy of dislocations were calculated as a function of the composition and the milling time. On the other hand, using the extended convolutional multiple whole profile fitting procedure, the variations in the crystallite size and size distribution of FCC and BCC phases were studied. Finally, the stacking fault probability was calculated in different milled samples. It is revealed that smaller steady state crystallite size of samples with higher Fe content, is relevant to reduction of the outer cut-off radius of dislocation. On the other hand, the density of dislocations and stacking faults increased continuously up to 96 h of milling.
10.1016-j.jallcom.2013.12.088	-1		A melt encasement (fluxing) technique has been used to systematically study the microstructural development and velocity-undercooling relationship of a Cu-8.9 wt%Ni alloy at undercoolings up to 235 K. A complex series of microstructural transitions have been identified with increasing undercooling. At the lowest undercoolings a < 1 0 0 > type dendritic structure gives way to an equiaxed grain structure, consistent with the low undercooling region of grain refinement observed in many alloys. At intermediate undercoolings, dendritic growth returns, consisting of dendrites of mixed < 1 0 0 > and < 1 1 1 > character. Within this region, 8-fold growth is first observed at low undercoolings, indicating the dominance of < 1 0 0 > character. As undercooling is increased, < 1 1 1 > character begins to dominate and a switch to 6-fold growth is observed. It is believed that this is an extended transition region between < 1 0 0 > and < 1 1 1 > dendrite growth, the competing anisotropies of which are giving rise to a novel form of dendritic seaweed, characterised by its containment within a diverging split primary dendrite branch . At higher undercoolings it is suggested that a transition to fully < 1 1 1 > oriented dendritic growth occurs, accompanied by a rapid increase in growth velocity with further increases in undercooling. At the highest undercooling achieved, a microstructure of both small equiaxed grains, and large elongated grains with dendritic seaweed substructure, is observed. It is thought that this may be an intermediate structure in the spontaneous grain refinement process, in which case the growth of dendritic seaweed appears to play some part.
10.1016-j.jallcom.2013.12.109	4	transformation; martensite; martensitic; phase; shape; beta; memory; shape memory; temperature; temperatures; martensitic transformation; gamma; transformation temperatures; effect; thermal	This paper reports on the possibility to obtain Cu-Zn-Al films with 2H martensitic structure by fixing the valence electron concentration per atom (e/a) approximate to 1.53. Films with thickness of approximate to 5 mu m with micrometric grains show martensitic transformation temperature and hysteresis values close to the ones found in bulk samples. This result is different to the one found in Cu-Zn-Al thin films with 18R martensitic structure and similar microstructure, in which the hysteresis presents an increment (approximate to 10 times) compared to bulk samples. This difference can be associated to the intrinsic nature of the 2H transformation which requires more undercooling to produce the nucleation of the martensitic phase. The driving force for the burst-type martensitic transformation decreases the influence of the microstructure in the transformation.
10.1016-j.jallcom.2013.12.156	-1		To demonstrate the effect of processing on the microstructure and subsequent mechanical property of bulk metallic glasses, we prepared two alloys, Cu-47.5Zr47.5Al5 and Cu47.5Zr48Al4Co0.5, using two different designs of suction mold-one with a sharp inlet and one with a blunt inlet. The two alloys have been demonstrated previously to be ductile via phase transformation of the B2 phase and twin formation during plastic deformation. Microstructures of the as-cast as well plastically deformed samples, in particular, the size and distribution of the B2 phase, were examined using X-ray diffraction, scanning and transmission electron microscopy. Compressive tests were conducted on samples cast by different molds and their properties were found to closely correlate with the B2 morphology. Fluid dynamics during suction casting was also analyzed. Effects of Vena contracta, flow velocity, and Reynolds number were discussed and compared favorably with experimental observations.
10.1016-j.jallcom.2014.02.114	-1		Three Cu100-xNix alloys, with x = 23, 33 and 45 at% Ni, have been evaluated for use as substrates for coated conductors on the basis of measurements of their microstructure, crystallographic texture and hardness. It is found that high-temperature annealing after heavy rolling generates strong cube textures in each investigated alloy. For all of these alloys an increase in the annealing temperature from 800 to 1000 degrees C strengthens the cube texture and reduces the fraction of high angle grain boundaries. In the Cu-23 at% Ni and Cu-33 at% Ni alloys annealed at 1000 degrees C for 1 h, the fraction of the cube texture approaches 100% and the fraction of high angle boundaries is less than 4%. These two alloys are however very soft in the annealed condition. The cube texture in the Cu-45 at% Ni substrate is slightly weaker than in the two other alloys, but this substrate is considerably harder, which makes it better suited for large scale production of superconducting tapes.
10.1016-j.jallcom.2014.04.200	6	grain; deformation; strain; strength; dislocation; cu-; tensile; size; ecap; grain size; sfe; ductility; hardening; high; stress	Cu-2.5 at% Al-2.5 at% Zn, Cu-4.5 at% Al-22.8 at% Zn and Cu-12.1 at% Al-4.1 at% Zn alloys with stacking fault energies (SFEs) of 40, 10, and 7 mJ/m(2), respectively, were processed by combination of room temperature rolling (RR) and liquid nitrogen temperature rolling (LNR). The effect of SFE on microstructure refinement and mechanical properties of these materials were investigated. Microstructural observations indicate that a decrease in SFE leads to a decrease in crystallite size and to increase in microstrain, dislocation and twin densities for the RR and LNR samples. The results show that under the same deformation conditions, lower SFE promotes the formation of nanostructures and deformation twins. An analysis shows that the experimental results are consistent with a theoretical model which predicted the minimum grain size produced by milling.
10.1016-j.jallcom.2014.05.173	4	transformation; martensite; martensitic; phase; shape; beta; memory; shape memory; temperature; temperatures; martensitic transformation; gamma; transformation temperatures; effect; thermal	Incorporation of silver nanoparticles into Cu-based shape memory alloys is recommended to enhance their phase transformation behaviour. However, this incorporation can affect their transformation temperatures, mechanical, microstructural and corrosion characteristics. Four different phase reactions beta, alpha, NiAl and gamma(2) were detected on a derivative curve during the solidification by-computer-aided cooling curve thermal analysis. The highest fraction solid (82%) was calculated for the parent phase (beta) based on the Newtonian baseline method. The microstructural changes and mechanical properties were investigated using field emission scanning electron microscopy, X-ray diffraction tensile test and shape memory effect test. It was found that the addition of Ag can control the phase morphology and orientations along with the formation of the Ag-rich precipitates, and thus the tensile strength, elongation, fracture stress-strain, yield strength and shape memory effect are improved. Remarkably, the shape recovery ratio reached approximately 80% of the original shape. The corrosion behaviour of the Cu-Al-Ni shape memory alloy were investigated using electrochemical tests in NaCl solution and their results showed that the corrosion potential (E-corr) of Cu-Al-Ni SMA is shifted towards the nobler direction from -307.4 to -277.1 m V-SCE with the addition of 0.25 wt% Ag.
10.1016-j.jallcom.2014.07.010	-1		The microstructures, mechanical/electrical properties and precipitation behaviors of Cu-Zr-B alloy manufactured by double deformation-aging process were investigated. The results show that an excellent balance of tensile strength and electrical conductivity, e.g. as high as 575.4 MPa and 79.37% IACS, respectively, can be obtained for the alloy after primary 80% cold rolling and aging at 470 degrees C for 2 h followed by secondary 40% cold rolling and aging at 360 degrees C for 2 h . The achievement of such high strength and electrical conductivity can be attributed to the interactions of strain hardening and precipitation behaviors taking place in the course of double deformation and aging treatments. High softening resistance is the outgrowth of the occurrence of limited recovery and recrystallization. After secondary deformation and aging, discontinuous precipitation can be suppressed but continuous one promoted. It is found that the precipitates responsible for strengthening are fcc structure Cu5Zr with the orientation relationship of (10 (1) over bar)(M)//(2 (1) over bar(1) over bar)(P) and [111](M)//[111].
10.1016-j.jallcom.2014.08.141	4	transformation; martensite; martensitic; phase; shape; beta; memory; shape memory; temperature; temperatures; martensitic transformation; gamma; transformation temperatures; effect; thermal	The martensitic transformation on thermal cycling of the polycrystalline Zr(Cu0.5Co0.25Ni0.25) high temperature shape memory alloy was examined using in situ synchrotron X-ray diffraction. A single step B2 <-> B19' transformation was observed with a thermal hysteresis of 161 degrees C and a martensite finish temperature of 294 degrees C. Large anisotropic lattice constrictions and dilations, up to 1.3%, were observed during the course of transformation in the B19' martensite, but corresponding changes in the B2 austenite were not observed. The coefficients of thermal expansion in both phases were found to be quite large, 33 x 10(-6) degrees C-1 in B2 and 39, 88 and 29 x 10(-6) degrees C-1 for a(B19'), b(B19'), and c(B19') respectively. Possible mechanisms governing the transformation behaviour are discussed.
10.1016-j.jallcom.2014.08.197	11	glass; bulk; metallic; bulk metallic; gfa; bmg; glassy; metallic glass; ability; bulk metallic glass; amorphous; addition; crystallization; mm; glass-forming	The glass formation in the Ti-Cu system is revisited by means of the predictive gamma* and lambda + Delta h(1/2) amorphization criteria. Rapidly solidified ribbons of six selected compositions were investigated and in order to improve the glass-forming ability (GFA) minor amounts of Si were added to the best glass former predicted, Cu54Ti46. A series of (Cu0.54Ti0.46)(100-x)Si-x (x = 0.5, 1, 2) ribbons and rods with a diameter of 1 mm were prepared and analysed regarding their phase formation and thermal stability. For the alloy with the maximum GFA, (Cu0.54Ti0.46)(99)Si-1, the critical diameter for glass formation is below 1 mm. Nevertheless, a good correlation was found between the experimentally determined GFA of the alloys and the prediction given by the lambda+(Delta h)(1/2) and gamma* criteria. The addition of Si decreases the liquidus temperature and promotes the precipitation of the Cu4Ti3 phase instead of gamma-TiCu.
10.1016-j.jallcom.2014.09.010	-1		It is believed that the basic local cluster in metallic glasses (MGs) is the key to understand the origin of glass-forming ability (GFA) of MGs. Our ab initio simulations on the basic cluster in the binary Cu-Zr MGs as well as in the ternary Cu-Zr-Al(Ag) MGs provide the most straightforward evidence that the electronic stability of the basic cluster in MGs is the origin of the GFA. Our calculations reveal that the stability of the basic cluster is determined by its electronic states near the Fermi level. For the basic clusters in the best glass formers of Cu-Zr MGs, a gap near Fermi level is observed, indicating the stability of the basic clusters. With substitution of one Al(Ag) atom into the basic cluster in Cu50Zr50 MGs, a strong sp-d coupling of Al(Ag) with Cu and Zr is observed, which results in a stronger bonding and thus more stability of the basic cluster. Our findings provide a check for the atomic structural models proposed over the years for MGs, and have implications for understanding the formation and properties of MGs.
10.1016-j.jallcom.2014.09.047	-1		The effect of alloying seven different elements [Zn, Si, Fe, Ni, Mg, Cr and Ti] on the microstructure, hardness, phase precipitation and transformation temperature in a Cu-12.5Al-5Mn alloy with a view to possible improvements as a result of these additions is the focus of the reported study. The base alloy has been chosen keeping in mind its ability to exhibit shape memory properties and improved ductility over other Cu-based SMAs. The objective was to ascertain changes or improvements attained due to the individual tertiary additions. The samples were prepared through liquid metallurgy route using pure copper, aluminum, manganese and the respective quaternary alloying elements in right quantities to weigh 1000 g of the alloy in total and were melted together. Samples from the cast alloys were subject to homogenisation treatment at 200 degrees C for 2 h in a muffle furnace and furnace cooled. Samples from the homogenised alloys were heated and held for 2 h at 920 degrees C followed by ice quenching to obtain the desired martensitic structure for shape memory behaviour. The alloys in the cast, homogenised and quenched conditions were metallographically polished to observe the martensitic phase formation mainly in quenched samples which is a pre requisite for exhibiting shape memory properties in these alloys. X-ray Diffraction studies were carried out on the cast and quenched samples using Cu K alpha target; and the phases identified indicate martensitic phase precipitation; however in some cases the precipitation is incomplete. Differential Scanning Calorimetric [DSC] studies were carried out on quenched samples from room temperature to 600 degrees C maintaining a constant rate of 10 degrees C/min. Results indicate clear transformation peaks in all the samples which are significantly high than conventionally reported except with the addition of Mg in which case no distinct peaks have been recorded. The range of martensite retention is the maximum in ternary Cu-Al-Mn alloys; addition of quaternary elements decreases this range significantly. Presence of Ni delays austenite formation and completion [As and Af] significantly as compared to the ternary alloys; whereas with other additions the As and Af temperatures are brought forward. This means that whereas the alloys without quaternary additions would be better suited for its shape memory properties, ternary alloys would be better suited for higher transition temperatures. The role of different alloying additions has been highlighted in the findings. Variations in properties have been attained due to different additions and improvements attained in terms of higher transformation temperatures and martensite formation due to the alloying additions.
10.1016-j.jallcom.2014.09.184	4	transformation; martensite; martensitic; phase; shape; beta; memory; shape memory; temperature; temperatures; martensitic transformation; gamma; transformation temperatures; effect; thermal	The dilatometric study of plastically deformed Cu-15 wt%In and Cu-9 wt%Sb alloys, has been made. Thermal expansion variation, during continuous heating, was explained by using X-ray line profile and peak shift analyses. The dilatometric curves recorded for the deformed samples show two different behaviors. For the first alloy, cellular precipitation was not eliminated by deformation and gives with the recrystallization an important dilatometric contraction. Slow microstrain reduction and domain size growth affect the FWHM after primary recrystallization. The later was confirmed by the TEM observations of dislocations in the equilibrium matrix after heating up to 450 degrees C. The dominant lattice parameter effect during dissolution gives an important expansion. However, in the second alloy, the cellular precipitation disappeared. The occurrence of precipitation and dissolution reactions within the recrystallization stage, gives an important duplicated dilatometric contraction. Almost, the total microstrain reduction and domain size growth are revealed at the first half of the observed contraction. Then, the second half is due to the grains growth with a magnitude similar to that of the precipitation and recrystallization below 398 degrees C.
10.1016-j.jallcom.2014.09.206	4	transformation; martensite; martensitic; phase; shape; beta; memory; shape memory; temperature; temperatures; martensitic transformation; gamma; transformation temperatures; effect; thermal	The influence of 4 and 5 wt%Ag additions on the kinetics of beta [T-7-(CuMn)(3)Al] phase formation reaction in the Cu-9 wt%A1-6 wt%Mn alloy was studied using differential scanning calorimetry (DSC), X-ray diffractometry (XRD) and scanning electron microscopy (SEM). The results indicate that the conversion dependence of the activation energy has a descending shape, suggesting a multi-step process involving reversible reactions. The presence of Ag facilitates the formation of the beta phase. The results also showed that the Ag precipitates formation includes the dissolution of Mn and Al atoms, thus decreasing the partial fraction of these elements available to react.
10.1016-j.jallcom.2014.10.027	4	transformation; martensite; martensitic; phase; shape; beta; memory; shape memory; temperature; temperatures; martensitic transformation; gamma; transformation temperatures; effect; thermal	Cu-Al-Be single crystals show pseudoelasticity and the shape memory effect in a well-defined composition range. The beta(3)-18R martensitic transition is the origin of these phenomena. The transformation temperatures and the critical stresses to induce the martensitic transition are affected by diffusive phenomena taking place both in the parent phase and in martensite. Pseudoelastic cycles were used to obtain quantitative data concerning the effect of diffusive phenomena like stabilization of martensite, ordering of the parent phase under load and recovery of this phase on the critical stresses to transform. Information was then obtained on changes in the relative phase stability. A model is presented to explain those changes taking place in the parent phase aged under load and in the martensitic 18R structure. Experimental data on the kinetics of diffusive phenomena is also presented and analyzed.
10.1016-j.jallcom.2014.10.037	-1		Understanding the precipitate kinetics of Ag in proeutectic Cu is valuable to optimize the precipitation and morphology of Ag for high strength high conductivity hypoeutectic Cu-Ag alloys. The precipitation behaviors of as-solution treated Cu28 wt%Ag alloys were analyzed by differential scanning calorimetric (DSC). The results indicated that the activation energies of Ag-rich phase formation and dissolution were 55.3 +/- 22.4 kJ/mol and 129.1 +/- 20.7 kJ/mol, respectively. The as-solution alloy was further aged at different temperatures for 2 h . Their microhardness and electrical resistivity were measured. The results demonstrated that at the ageing temperature of 405 degrees C, less scattering effects reflected more Ag precipitations from Cu matrix than the rest of temperatures. At 475 degrees C, however, Ag precipitates produced more strengthening effects. Above results were related to the competition between precipitation and dissolution of Ag in proeutectic Cu. This interpretation is supported by TEM observations on Ag precipitation.
10.1016-j.jallcom.2014.10.041	-1		The amorphous Cu50Zr40Ni5Ti5 alloy was produced by melt-spinning at wheel speeds of 35,38 and 41 m s(-1). The resulting melt-spun ribbons were characterised using X-ray diffraction (XRD), scanning electron microscopy coupled with energy dispersive spectroscopy (SEM-EDX), differential scanning calorimetry (DSC) and Vickers microhardness (HV) tester. The XRD and SEM results revealed that the rapidly solidified ribbons have a fully amorphous structure. After partial or fully crystallisation of Cu50Zr40Ni5Ti5 ribbons upon annealing, the microstructure had uneven and irregularly shaped features with the existence of Cu10Zr7, Cu8Zr3, CuZr and FCC-Cu phases while as quenched ribbons had featureless microstructure. The SEM-EDX analysis confirmed compositional homogeneity of the Cu50Zr40Ni5Ti5 alloy ribbon. According to DSC results, the amorphous ribbons exhibited distinct glass transition temperature (T-g) and wide supercooled liquid region (Delta T-x = T-x-T-g) before crystallization. Accordingly, T-g and Delta T-x are around 409-414 degrees C and 37-54 degrees C, respectively. The microhardness of the as-quenched ribbons was about 522 HV while it decreased with increasing annealing temperature and had a value of 463 HV for 725 degrees C.
10.1016-j.jallcom.2014.10.101	-1		The temperature dependence of the relaxation times of Cu46Zr46Al8 glass was measured by means of mechanical spectroscopy and static stress-relaxation measurements. The weak intensity of secondary relaxation in this alloy allows us to correlate the characteristic times of dynamic and static measurements of primary relaxation. The glassy dynamics of an isoconfigurational state are found to follow an Adam-Gibbs-Vogel expression with the glassy state defined by a fictive temperature. The combination of both measurements proves that, in the frequency domain, the relaxation response can be well described by a single relaxation function above and below the glass transition. The change in relaxation times as function of the fictive temperature and the corresponding effects on the mechanical behavior are estimated and discussed.
10.1016-j.jallcom.2014.10.123	10	composites; nanoparticles; strength; matrix; high; strengthening; particles; conductivity; composite; electrical; mpa; sintering; ods; grains; mechanical	Strength and ductility are two of the most important, but often mutually exclusive, mechanical properties of structural materials. Here we report a new kind of nonstoichiometric TiC0.5 reinforced Cu-Al matrix composite fabricated by sintering a coarse particle mixture of Ti2AlC and Cu. The composite has an optimal microstructure of submicron matrix grains reinforced by submicron TiC0.5 particles and some nano TiC0.5 particles which were dispersed within the matrix grains. This microstructure endows the TiC0.5/Cu-Al composite with a tensile strength of 498 MPa and a tensile elongation of 10.5% at room temperature. The improved mechanical properties of the TiC0.5/Cu-Al composite are attributed to a multiple strengthening mechanism, including fine-grain strengthening, dispersion strengthening and solid-solution strengthening.
10.1016-j.jallcom.2014.11.193	-1		New CuxNb1-x alloys were prepared using a two-step process of ball milling and subsequent high pressure torsion compacting at ambient temperature. The alloys showed a nanocrystalline structure with grain sizes between 13-26 nm for the Cu-rich samples and 11-13 nm for the Nb-rich samples. The grain sizes decreased with the milling time and the amount of Nb in the Cu-rich and Cu in the Nb-rich samples, respectively. The distortion of the crystallographic lattice of the fcc Cu and bcc Nb suggests the formation of a solid solution. The mechanical properties studied by nanoindentation show an increase of the hardness with milling time and the amount of added element. A thermal treatment was carried out under a protective Argon atmosphere. Up to 400 degrees C the Cu-rich samples do not show significant signs of oxidation and in increase of hardness. The Nb-rich samples showed a continuous increase of the hardness up to 500 degrees C, due to the precipitation of Cu, and the initial formation of NbOx.
10.1016-j.jallcom.2015.01.036	11	glass; bulk; metallic; bulk metallic; gfa; bmg; glassy; metallic glass; ability; bulk metallic glass; amorphous; addition; crystallization; mm; glass-forming	The effect of RE addition on glass-forming ability (GFA) and mechanical properties of (Cu47Zr45Al8)(100-x)REx (RE = Ce, Nd, Gd, Y, Dy, Lu, x = 0-4 at%) bulk metallic glasses (BMGs) has been studied in this paper. It has been found that trace amount of rare-earth addition in the Cu-rich Cu-Zr-Al alloys can decrease the temperature of glass transition (T-g) and increase gamma(gamma = T-x/(T-g + T-l)) value, and therefore improve the GFA. The (Cu47Zr45Al8)(96)Y-4 bulk metallic glass with critical diameter of 25 mm was prepared by copper-mold-casting. The (Cu47Zr45Al8)(97)Lu-3 bulk metallic glass exhibited good plasticity 4.65% at room temperature during compression test, which was applied high yield strength of 1840 MPa. With the increase of rare-earth elements addition up to 4 at%, the fracture strength of the alloy reduced obviously and no more plastic deformation can be observed on the fracture surface. Young's modulus, fracture strength and Poisson's ratio were investigated for the mechanism of deformation (from plasticity to brittleness) in the compression tests.
10.1016-j.jallcom.2015.01.208	-1		In this study, the effect of accumulative roll bonding (ARB) process on the electrochemical behavior of pure copper in 0.01 M borax solution has been investigated. The microhardness tests showed that by implementing the ARB process the values of microhardness improve with increasing the number of ARB cycles. Moreover, a drastic increase of microhardness was seen (similar to 100%) after the second ARB cycle. Potentiodynamic polarization plots and electrochemical impedance spectroscopy (EIS) measurements showed that increasing the number of ARB cycles offer better conditions for forming the passive films. In the Mott-Schottky analysis, no evidence for n-type behavior was obtained, indicating that the oxygen vacancies and the copper interstitials do not have any significant population density in the passive films. Also, this analysis revealed that with increasing the number of ARB cycles, the acceptor density of the passive films decreased.
10.1016-j.jallcom.2015.01.298	16	wear; composite; composites; powders; milling; particles; powder; wt; sliding; friction; hardness; matrix; mechanical; surface; properties	Copper-based composites reinforced with 15-35 wt% SiC were produced by mechanical alloying in a planetary mill and hot pressing. Grinded copper chips less than 5000 mu m in size and 10 mu m SiC particles were used as initial materials. Optical and scanning electron microscopes were used for microstructural analysis. The paper analyzes the effect of SiC content on hardness, electrical conductivity, density and CTE. The results demonstrate that an increase in milling time and SiC content (up to 25 wt%) leads to a higher hardness of the materials due to homogenization of the microstructure and refinement of the reinforcing particles. With an increase in SiC content over 25 wt% (48 vol.%), the hardness decreases because of an intense reduction of the microstructural homogeneity and an increase in the porosity of compact specimens.
10.1016-j.jallcom.2015.02.057	-1		Al2O3 bulk nano-composites were prepared by combining Cu-Al alloy sheets internal oxidation with hot extrusion. Cu-0.16 wt% Al alloy sheets, 90 mm in diameter and 0.5 mm thick were internally oxidized with Cu2O + Cu + Al2O3 mixed powders at 900 degrees C for 8 h . Nano-sized Al2O3 particles were distributed in the Cu matrix with a coherent interface. The orientation relationship between the Cu matrix and the Al2O3 particle was [2 1 (1) over bar](Cu)//[(1) over bar 1 0](Al2O3), (022)(Cu)//(220)(Al2O3) and (1 (1) over bar 1)(Cu)//(0 0 (2) over bar)(Al2O3). Oxidized sheets were cleaned, stacked, vacuum sealed and hot extruded at 800 degrees C to prepare Cu-Al2O3 nano-composite rods with a 20 mm diameter. The Cu-Al2O3 rods were cold drawn to a wire with a diameter of 3 mm. The hot extruded rod and the cold drawn wire cross-sections presented concentric rings features, resembling tree rings. In the rings structure, the closer to the edge of the rod or the wire, the thinner the Cu-Al2O3 sheets were with better interfacial bonding. The electrical conductivity of the rod was 96.3% IACS (International Annealed Copper Standard). The electrical conductivity, yield strength, tensile strength and reduction of the cross-sectional area of the drawn wire were 94.1% IACS, 417 MPa, 445 MPa and 80.2%, respectively. The paper demonstrates a feasible way to prepare Cu-Al2O3 bulk nano-composites.
10.1016-j.jallcom.2015.03.183	16	wear; composite; composites; powders; milling; particles; powder; wt; sliding; friction; hardness; matrix; mechanical; surface; properties	Elemental powders of nanosized tungsten and chemically deposited nanosized copper were used for preparing tungsten/copper composites, which are used as electric contact components. A composite of 70 wt%W/30 wt%Cu (52 vol%W/48 vol% Cu) composition was prepared by three powder metallurgy techniques. Elemental mixing, mechanical milling and electroless Cu coating on tungsten particles were used for the synthesis. The obtained powder blends underwent consolidation by rapid hot pressing using the spark plasma sintering (SPS) route at 950 degrees C under vacuum and by conventional vacuum pressureless sintering for comparison. The elemental powders and the sintered composites were investigated by optical microscopy and SEM. Electrical conductivity, hardness, transverse rupture strength, and wear properties were measured. Results show that the synthesis of the composite by the investigated route yields good performance. Samples prepared by SPS have shown better mechanical properties than those prepared by compaction and sintering due to their fine microstructure.
10.1016-j.jallcom.2015.03.218	-1		A Cu-0.3 wt% Mg-0.05 wt% Ce alloy was designed and prepared by melting and casting. After hot rolled, the ingot was cut into rod-shape samples for equal channel angular pressing (ECAP) with different passes at room temperature. The microstructure evolutions were investigated using transmission electron microscope (TEM) observation and electron backscatter diffraction (EBSD) analysis. The severe plastic deformation (SPD) caused by ECAP made the grains elongated significantly. With the increase of ECAP passes, the fraction of high-angle boundaries (HABs) (0 >= 15 degrees) increased and the microstructure was refined. Tension testing results indicated that the tensile strength was remarkably improved from 273.4 MPa before ECAP to 587.5 MPa after 8 passes of ECAP, maintaining an appropriate elongation of 11.4% and good electrical conductivity of 73.1% IACS. After annealing treatment at 300 degrees C for 2 h, the ECAP samples still maintained excellent comprehensive properties: tensile strength was 558.2 MPa, electrical conductivity was 74.7% IACS, and elongation was 13.2%, which showed bright prospect in highspeed railway as a contact wire material.
10.1016-j.jallcom.2015.03.226	-1		Metal composites have attracted great interest for the combination of high strength and high electrical conductivity. We take the Cu-3 wt% Cr composite as a model system to reveal the structure-property relations in a large range of drawing strains (eta), and propose the strengthening mechanism during cold drawing. At small and moderate drawing strains, the incoherent and semi-coherent interfaces are effective barriers for dislocation motion and pile-up. The mechanical behaviors are described well by the Hall-Petch relation. The work hardening at eta < 4.5 is the direct consequence of the grain refinement and the increasing density of phase boundaries, which can be well modelled by a linear rule of mixture. Deviation is observed at eta > 4.5, when the strength gradually reaches a plateau. Microstructural analysis reveals that further refinement can hardly occur at high drawing strains due to the dynamic recovery process. Another characteristic of the turning point is the structural homogenization, i.e. the mechanical alloy induced inter-mixing and the full coherency. The transition of the interface coherency is clearly identified by both electron diffraction and high resolution transmission electron microscopy. The structural homogenization at the interface may alleviate the interfacial blockage to the dislocation slipping, indicating the existence of an interfacial strength limit. The linear rule of mixture is modified to account for this effect at eta > 4.5. The complete mechanical behavior of the Cu-3 wt% Cr composite is captured by a piece-wise function.
10.1016-j.jallcom.2015.04.012	-1		This work investigates the formation of a Cu3Au-nitride alloy using experimental and computational methods. For this purpose, we prepared a custom-made Cu-Au target and then hit it with argon ions in the presence of molecular nitrogen that produced a film on Corning glass. This film was analyzed using spectroscopic and diffraction techniques. The four-point-probe method and Tauc plots were applied to determine the electrical and optical properties of this thin film. Using first principle calculations a structural model was constructed that validated our observations. The crystalline system that we used was cubic (Pm3m space group) with half the sites filled with Au randomly. The composition was close to Cu3Au0.5N. In agreement with the electrical measurements and calculations, the Cu3Au0.5N band structure was highly affected by the Au incorporation since the electrical resistance and carrier density were in the 10(-3) Omega cm and 10(22) cm(-3) ranges, respectively, and the optical gap decreased 0.61 eV with respect to the Cu3N. The material was a pseudo-gap conductor with conductance as good as a heavily-doped semiconductor at room temperature; this should give it great potential for use in the optoelectronics industry.
10.1016-j.jallcom.2015.05.233	-1		Cu100-xZrx (x = 50, 54, 60 and 66.6) polycrystalline alloys were prepared by arc-melting. The crystal structure of the ingots has been examined by X-ray diffraction. Non-equilibrium martensitic phases with monoclinic structure were detected in all the alloys except Cu33.4Zr66.6. Temperature dependencies of electrical resistivity in the temperature range of T = 4-300 K have been experimentally obtained as well as room temperature values of Hall coefficients and thermal conductivity. Electrical resistivity demonstrates anomalous behavior. At the temperatures lower than 20 K, their temperature dependencies are non-monotonous with pronounced minima. At elevated temperatures they have sufficiently non-linear character which cannot be described within framework of the standard Bloch-Gruneisen model. We show that experimental resistivity dependencies may be perfectly fitted by generalized Bloch-Gruneisen model with variable Debye temperature. We found that both the electrical resistivity and the Hall coefficients reveal metallic-type conductivity in the Cu-Zr alloys. The estimated values of both the charge carrier mobility and the phonon contribution to thermal and electric conductivity indicate the strong lattice defects and structure disorder.
10.1016-j.jallcom.2015.05.287	6	grain; deformation; strain; strength; dislocation; cu-; tensile; size; ecap; grain size; sfe; ductility; hardening; high; stress	The static-annealing behavior of cryogenically-rolled Cu-30Zn brass over a wide range of temperature (100-900 degrees C) was established. Between 300 and 400 degrees C, microstructure and texture evolution were dominated by discontinuous recrystallization. At temperatures of 500 degrees C and higher, annealing was interpreted in terms of normal grain growth . The recrystallized microstructure developed at 400 degrees C was ultrafine with a mean grain size of 0.8 mm, fraction of high-angle boundaries of 90 pct., and a weak crystallographic texture.
10.1016-j.jallcom.2015.06.136	-1		The color of Cu-Zn brasses range from the red of copper through bright yellow to grey-silver as the Zn content increases. Here we examine the mechanism by which these color changes occur. The optical properties of this set of alloys has been calculated using density functional theory (DFT) and compared to experimental spectroscopy measurements. The optical response of the low Zn content alpha-brasses is shown to have a distinctly different origin to that in the higher content beta', gamma and epsilon-brasses. The response of beta'-brass is unique in that it is strongly influenced by an overdamped plasmon excitation and this alloy will also have a strong surface plasmon response.
10.1016-j.jallcom.2015.09.130	17	wear; composites; coating; friction; composite; coatings; surface; tribological; properties; wear resistance; resistance; powder; sliding; matrix; wear rate	A Cu-Ni-Mn alloy based hardfacing coating reinforced by WC particles is deposited on steel substrates by a manual oxy-acetylene weld hardfacing method. Microstructure and wear resistance performance of the fabricated hardfacing coatings are investigated. There are no cracks or other defects observed in the hardfacing coating. Uniform distributed WC particles in the composite hardfacing coating are not dissolved, and its volume fraction is up to about 63%. A sound bond is formed at the interface of WC and Cu-Ni-Mn alloy, and the bond between the coating and the steel substrate is reliable. With silica sands, the wear resistance performance of the composite hardfacing coatings is about 4 times better than that of the high-Cr cast iron, and its volume loss presents approximately a linear relationship with the sliding distance. The main wear mechanisms are the plastic extrusion of the Cu-Ni-Mn matrix and the fracturing of WC-reinforcement particles under three-body abrasive wear condition in this paper.
10.1016-j.jallcom.2015.09.250	-1		Cu-1 wt%Al2O3 composite powder, prepared by mechanical milling and consolidated by spark plasma sintering to have about 98-99% of theoretical density, were characterized by scanning electron microscope, focused ion beam microscope, X-ray diffraction, nanoindentation and transmission electron microscope. The mechanically milled powders, upon consolidation, exhibited a finer grain size of 2 mu m. Tensile deformation behavior of this composite, at ambient temperature but over the strain rates of 10(-4) s(-1) to 5 x 10(-2) s(-1), exhibited typical manifestations of dynamic strain ageing in the form of serrations and negative strain rate dependence of flow stress. The yield and ultimate tensile strengths, and so also the elongation decrease gradually with increase in strain rate. Such variation was also shown by nanoindentation hardness as a function of loading rate over 1-100 mN/s. The observed results are explained by the dislocation structure evolved from its interaction with Al2O3 dispersoids and impurity atoms like Fe, C and O coming from the powder processing.
10.1016-j.jallcom.2015.10.061	-1		In this study, copper-based composites containing nanoscale TiC with high strength and high electrical conductivity (712 MPa and 72% IACS) were produced by a newly developed mechanical milling process. As-milled powder mixtures were investigated by X-ray diffraction (XRD) analysis. The results indicated that the lattice parameters of copper were increased with progress of milling due to the formation of solid solution of Cu (Ti, C). There was no transformation of Ti and C into TiC phase during the high energy milling process. It was found that the TiC particles were firstly formed during the sintering process. The effects of SPS parameters including sintering temperature and pressure on electrical and mechanical properties of sintered samples were systematically investigated. The heat treatment process after SPS was found to increase the electrical conductivity greatly as the proceeding reaction of Ti/C results in an extremely low Ti concentration in Cu matrix. Moreover, an obvious drop in microhardness was observed. The strength was slightly improved by the following hot pressing, while there was no obvious change in electrical conductivity. The microstructure evolution during the entire developed process was analyzed by means of Electron backscatter diffraction (EBSD) and transmission electron microscopy (TEM). The formed TiC particles were homogeneously distributed in copper matrix. Furthermore, the ultrafine-grained (UFG) structure developed by the present process could maintain stable because of the Zener pinning effect caused by nanoscale TiC particles located at grain boundaries.
10.1016-j.jallcom.2015.10.230	-1		The Cu-Zr-Ag ternary system belongs to the Cu-based bulk amorphisable alloy systems. The solidification of the amorphisable alloy is still not well-understood. The identification and characterization of the crystal structure of the solidified phases are essential for describing the ternary system. A typical Cu-rich solidified phase in the Cu-Zr-Ag ternary system is the so-called m-phase. The structure of this phase was not known before. Another typical phase is the Ag-containing Cu10Zr7 phase. We determined and refined the crystal structures of single crystals of these two phases by transmission electron microscopyusing precession electron diffraction technique and diffraction tomography (performed by ADT3D software). The determination and refinement procedure was achieved in SIR2008, SIR2011 and SHELXL software packages. In conclusion, precession electron diffraction technique combined with diffraction tomography makes it possible to determine the crystal structure of materials with sub-micrometer sized crystals such as alloys when single crystal X-ray diffraction based structure determination fails.
10.1016-j.jallcom.2015.10.290	-1		The precipitation behavior and properties of Cu-0.23Be-0.84Co alloy aging at 460 degrees C for 0 h, 0.5 h, 1 h, 2 h, 3 h, 4 h, 5 h, and 6 h were investigated systematically by transmission electron microscopy (TEM) and high-resolution transmission electron microscopy (HRTEM) in this study. With increase of aging time, the morphology, size, and distribution of precipitates change significantly, giving rise to the hardness and electrical conductivity change as well. It is confirmed that the phase transformation of Cu-0.23Be-0.84Co alloy during aging process follows the sequence of gamma '' -> gamma' -> gamma phase. The spherical gamma '' phase has a body centered cubic (b. c. c.) structure with the lattice parameters of 0.28-0.29 nm, and the size increases from 2-5 nm to 5-7 nm after aging for 0.5 h(-1) h . The gamma '' phase aligns the Cu matrix according to the following orientation: (110)alpha//((1) over bar 00)gamma '' and [1 (12) over bar]alpha//[01 (1) over bar] gamma ''. The ellipsoidal gamma' phase forms after aging for 3 h and has a consistent and ordered distribution on the Cu matrix. The orientation relationship between gamma' phase and the Cu matrix can be stated as (110)alpha//(3 (1) over bar1)(gamma') and [(1) over bar 13]alpha//[(1) over bar 14](gamma') with the lattice parameters of 0.26 nm. After aging for 4 h-6 h, the ellipsoidal gamma' phase gradually transforms into the coarse and spherical g phase, and the orientation of precipitates is disordered. In addition, the hardness and electrical conductivity of Cu-0.23Be-0.84Co alloy have an obvious change with the aging time. The change of performance can be explained by the precipitation behavior of Cu-0.23Be-0.84Co alloy during aging. It is especially noteworthy that, due to the formation of consistent and ordered gamma' precipitates, the hardness and electrical conductivity has a peak value of 121 HB and 64.6%IACS (International Annealed Copper Standard) after aging for 3 h based on the experimental results in this study, respectively.
10.1016-j.jallcom.2015.10.299	4	transformation; martensite; martensitic; phase; shape; beta; memory; shape memory; temperature; temperatures; martensitic transformation; gamma; transformation temperatures; effect; thermal	Conditions of intermetallic phase synthesis during layerwise selective laser sintering/melting in Cu-Al-Ni powdered system were explored. There to we used optical and scanning electron microscopy, EDX and XRD analysis for microstructure testing and intermetallide identification in porous 3D samples depending on the laser syntheses regimes. A high laser sintering ability of the prepared mixtures and shape memory effect in 3D samples by results of specific electrical resistance measurements were shown. Porosity of the laser-synthesized Al7Cu4Ni intermetallide led to a peak shifting by the temperature axis and the intervals of the A(s)-A(f) austenite transformation and M-s-M-f martensite transformation were 50 divided by 80 degrees C and +25 divided by -40 degrees C respectively.
10.1016-j.jallcom.2015.11.103	-1		Spinodal decomposition is a typical type of phase transformation during aging of Cu-Ni-Si alloys which brings down the electrical conductivity; however in the present work Spinodal decomposition has been found to be suppressed by some addition of Co. Cu-2.8Ni-0.6Si and Cu-1.4Ni-1.2Co-0.6Si (wt%) alloys have been prepared and solutioned at 900 degrees C, followed by aging at 400-600 degrees C for 0-16 h . Microstructure has been analyzed using X-ray diffraction and transmission electron microscopy. Bright field images and selected-area diffraction patterns prove that Co addition has hindered the occurrence of Spinodal decomposition. Microhardness and electrical conductivities of have been improved by adding Co. The improvement has been explained by analyzing the microstructural observation.
10.1016-j.jallcom.2015.11.140	-1		The influence of trace elements on the powder metallurgy of Cu was investigated. It was found that 1 wt. % of Ti can effectively increase the green density of the compacts and facilitate the subsequent sintering process, thus resulting in increased sintered density. Although 1 wt. % of W added into the Cu leads to similar increasing of green density, W significantly retarded the sintering process and has a negative effect on the sintered density. Moreover, intermetallic Cu4Ti were formed, which not only creates a short-circuit diffusion path for Cu but also forms liquid phases during sintering. However, it was hardly dissolved between W and Cu.
10.1016-j.jallcom.2015.12.015	0	solidification; phase; magnetic; magnetic field; undercooling; field; liquid; separation; peritectic; immiscible; cu-; dendrite; phase separation; microstructure; primary	Solidification microstructures have been examined in Cu-Pb and Fe-Sn alloys over a wide range of hypermonotectic compositions in which the core-shell structure was produced under reduced gravity condition in a 3 m drop tube. The contributions of alloy composition to the formation potential of core-shell microstructure were determined. It was found that the core-shell structure was obtained in the alloys with compositions near and on the left side not far away from critical point and it could be double-and triple-layer. The low melting point phase, Pb-rich phase in Cu-Pb alloys and Sn-rich phase in Fe-Sn alloys, always forms the shell in two-layer structure and it also forms the core in the three-layer structure. The Marangoni velocity was calculated to show the migration characteristics. The alloys with the critical composition experiences the longest migration period partly due to the less time consuming of the spinodal decomposition than the nucleation and partly due to the deepest miscibility gap, so that the core-shell microstructure is produced easily. With the composition departs from the critical point to the two sides in the miscibility gap, the formation ability of the core-shell structure decreases. The small migration velocity caused by the different thermophysical parameters of the two liquid phases for the alloy with the composition larger than the critical value leads to the difficulty for forming the core-shell structure.
10.1016-j.jallcom.2015.12.017	-1		The fatigue crack growth (FCG) behaviors of Cu-Be-Co-Ni alloy subjected to interrupted aging (IA), normal aging (NA) and overaging (OA) treatment were discussed. The distinctions in microstructure of the alloys after various aging treatments led to different FCG behaviors. In order to understand the different FCG behaviors, a model based on the reversible plastic zone (RPZ) size and microstructural factors was applied in this study. At the relatively low stress intensity factor range (Delta K < 17 MPa m(1/2)), the RPZ size of each sample was smaller than the corresponding grain size, so the fatigue crack propagated inside the grain and adjacent to the grain boundaries (GBs). For the IA alloy, fine and coherent gamma '' precipitates which could be sheared by dislocations promoted the fatigue crack resistance, leading to the decrease of FCG rate. When the value of stress intensity factor range becomes higher (Delta K > 21 MPa m(1/2)), the RPZ size of each sample was 1-2 times of the corresponding grain size. Consequently, the crack trended to grow along GBs. For the OA alloy, the crack propagated along the interfaces between the discontinuous precipitation (DP) cells and parent phase. The tortuous interfaces hindered the propagation of the fatigue cracks, resulting in the reduction of FCG rate.
10.1016-j.jallcom.2015.12.187	11	glass; bulk; metallic; bulk metallic; gfa; bmg; glassy; metallic glass; ability; bulk metallic glass; amorphous; addition; crystallization; mm; glass-forming	The glass-forming ability (GFA) of (Cu0.5Zr0.5)(100-x)Zn-x (x = 1.5, 2.5, 4.5, 7, 10, and 14 at%) metallic glasses (MGs) was studied. With increasing Zn content, the GFA of CuZr-based MGs gradually increases, enabling the fabrication of Cu-Zr-Zn bulk metallic glasses (BMGs) and metallic glass matrix composites. The enhancement of GFA with Zn addition to the CuZr binary alloy is well explained by considering topological instability and electronic criteria. Upon annealing of Cu-Zr-Zn MGs Cu10Zr7 and subsequent CuZr2 crystals precipitate in the glassy matrix, being followed by the nucleation of B2 CuZr crystals. It is shown that Zn addition can effectively stabilize B2 CuZr phase to lower temperatures. Analysis of the crystallization kinetics of Cu-Zr-Zn MGs under isothermal conditions shows that the dominated crystallization mechanism is the interface-controlled two- or three-dimensional growth with different nucleation rates.
10.1016-j.jallcom.2016.03.085	16	wear; composite; composites; powders; milling; particles; powder; wt; sliding; friction; hardness; matrix; mechanical; surface; properties	In this research, copper matrix composites reinforced with different amounts of titanium carbide particles were produced by mechanical milling and in-situ formation of reinforcements. Morphology and size of milled powders were inspected by scanning electron microscopy (SEM) several times during milling process. Changes in lattice parameter, crystallite size, lattice strain, dislocation density and Gibbs free energy changes (due to increasing in dislocation densities and grain boundaries) in different samples (with different TiC particles contents) were studied by X-Ray Diffraction technique with Cu-ka radiation and using NelsoneRiley method and Williamsone-Hall equation. Microstructure of samples after sintering was investigated by FESEM. Finally, densitometry, hardness, determination of electrical resistance and pin on disk wear test were performed and effect of reinforcement percentages on the physical and mechanical properties of composites was studied. Results show incredible improvement in mechanical properties with increasing in TiC value, even though, electrical conductivity dropped off considerably.
10.1016-j.jallcom.2016.04.006	2	corrosion; surface; film; electrochemical; films; spectroscopy; layer; current; solution; potential; resistance; composition; x-ray; ions; showed	A study was made to evaluate the corrosion behavior when Cu-30Zn alloy is reinforced with different weight fractions of silicon carbide (SiC) particles in a simulated sea solution (3.5 wt% NaCl aqueous solution). The composites were produced via powder metallurgy (PM) route. For the sake of comparison, the corrosion behaviors of unreinforced and reinforced alloy were examined. Electrochemical measurements (potentiodynamic testing) showed that the corrosion rate of the composites decreased with increase of SiC weight percentages, as a result of weak microgalvanic couple between reinforcement particles and Cu-30Zn matrix, and the low possibility of intermetallic phases formation. ANOVA test indicated that the variations of corrosion rate of the composites upon changing weight percentages of SiC particles are statistically significant. Polarization curves showed that the passive film tends to be less stable, and the potential difference between passivation and free corrosion points increased with increase of SiC weight percentages, as SiC cathodically protect the matrix material by sacrificial anodic dissolution of crevice regions about reinforcement particles. Scanning Electron Microscope (SEM) images of the sample's surfaces before and after testing are in agreement with the electrochemical results.
10.1016-j.jallcom.2016.04.321	-1		An ultrafine grained Cu-5vol.%Al2O3 composite with a microstructure consisting of bimodal Al2O3 particles distributing at the boundaries of ultrafine Cu grains was fabricated by a combination of high energy mechanical milling and powder compact extrusion. The material showed a high tensile yield strength of 486 MPa and high electrical conductivity of 80% of the international annealed copper standard (IACS). Analysis of the findings shows that such microstructure can be further tailored to achieve high strength and high electrical conductivity with ultrafine grained or nanocrystalline Cu matrix composites.
10.1016-j.jallcom.2016.05.021	-1		We have investigated the structure of Fe clusters which were induced by thermal-aging and their effect on magnetic properties of Cu-1.2 at% Fe alloy by using the extended X-ray absorption fine structure (EXAFS), the atom probe tomography (APT) and the SQUID magnetometer. Small Fe clusters with the diameter of 3.3 nm on average and solute Fe atoms in the solution-treated specimen show paramagnetism. At the initial stage of thermal-aging, Fe clusters with the diameter of 10.9-24.0 nm on average are produced, and most of them exist as anti-ferromagnetic gamma-Fe with fcc structure due to the coherent growth against the fcc Cu matrix. By the enough long time thermal-aging, some of these gamma-Fe clusters transform to ferromagnetic Fe clusters with bcc structure due to their growing up to enough large size. From the results obtained by EXAFS, the atomic fraction of Fe atoms forming bcc-structured clusters indeed increases with increasing the aging time. These results obtained by non-destructive EXAFS methods revealed that transformation from gamma-Fe to bcc-structured Fe occurs only by the thermal-aging. The effects of the Fe clustering on the electrical resistivity and the micro Vickers hardness, and effects of the plastic deformation will also be mentioned briefly.
10.1016-j.jallcom.2016.05.066	-1		The conductive pastes containing Ag particles are used for patterning the electrodes of electronic devices such as solar cells and touch screen panels. Although Cu@Ag type metal particles have been tried as a substitute instead of Ag for cost reduction, the dewetting of Ag from Cu core during the processes has limited the use of Cu as a core metal. In this work, to investigate the Cu-Ni alloys as the core metal, we analyze the surface structures of Cu-Ni alloys and measure the compatibility between Ag and Cu-Ni alloys as wells as Cu and Ni by calculating the contact angles of Ag droplet on the metal surfaces using molecular dynamics simulations. As the Ni content of Cu-Ni alloys increases, the contact angle decreases: the contact angles for Cu, Cu3Ni, CuNi, CuNi3, and Ni are 69.6, 52.6, 50.5, 45.1, and 8.9 degrees, respectively. Therefore, the wettability of Ag on the Cu-Ni alloys is improved with the Ni content in the Cu-Ni alloys. This result indicates that the Cu-Ni alloys could be good candidates as the core metal to be used in the metal particles for the conductive pastes.
10.1016-j.jallcom.2016.06.091	12	thermodynamic; ternary; phase; data; experimental; equilibria; phase equilibria; liquid; binary; experimental data; calculated; phases; literature; model; calphad	Thermodynamic data of seven Cu-Li-Sn alloys were determined by the Knudsen Effusion Mass Spectrometry (KEMS) for the solid, solid-liquid or liquid region. Thermodynamic activities of components, enthalpies and entropies of mixing were calculated in the temperature range of 623-933 K. The inter metallic phases Cu6Li3Sn4(s), CuLi2Sn2(s), and CuLi3Sn(s) have been described in literature quite recently. These phases were observed by powder X-ray diffraction (XRD) measurements after sample preparation. The thermodynamic data obtained by KEMS and the crystallographic data will enhance the available information for calculating the phase diagram for the ternary Cu-Li-Sn system by CALPHAD approach .
10.1016-j.jallcom.2016.06.155	6	grain; deformation; strain; strength; dislocation; cu-; tensile; size; ecap; grain size; sfe; ductility; hardening; high; stress	In this paper, a series of Cu-Al alloys (2.2, 4.5, and 6.9 wt pct Al) with decreasing stacking fault energy (SFE) were processed by surface mechanical attrition treatment (SMAT) to obtain a gradient structure (GS). The yield strength of SMAT-ed samples is attributed to the volume fraction of GS layer and the ductility is associated with the dynamic recovery during deformation. Kocks-Mecking model was utilized to describe the storage and annihilation of dislocations in these samples. The results show that the minimal K2, which represents dynamic recovering, appears in Cu-4.5 wt%Al alloy with a medium SFE, indicating a suppressed dislocation annihilation and a delayed plastic instability during plastic deformation. Repeated stress relaxation tests were applied to characterize the activation volume and the evolution of mobile dislocation. It turns out that the highest relative mobile dislocation density (rho m/rho m0) emerges in Cu-4.5 wt%Al sample. This could be ascribed to the sufficient twin boundaries (TBs) which can keep the accumulated dislocations slipping easily and lower the exhaustion of mobile dislocation. The high rho m/rho m0 demonstrates that more mobile dislocation is preserved and the dislocation annihilation is effectively prohibited in the sample, in accordance with the low K2 obtained from Kocks Mecking model, providing a reasonable interpretation for the good ductility.
10.1016-j.jallcom.2016.07.061	-1		A combination of High Energy Ball Milling in the planetary mills (HEBM) with Spark Plasma Sintering (SPS) allows production of dense (>97%) nano-composites of immiscible metals, Cu and Cr, so-called pseudo-alloys. New results on electrical resistance of the pseudo-alloys have been obtained from cryogenic to elevated temperatures, in comparison with the Cu-Cr micro-composites and pure Cu. The results show that duration of HEBM influences hardness and electric resistivity of the materials in a wide temperature range, including cryogenic residual resistivity. This influence remains after SPS. Increasing of the electrical resistivity and hardness with increasing of the mechanical impact is explained by significant increase of specific surface of grain boundaries due to grains refinement. At the same time, some regimes of HEBM results in increasing of the electrical conductivity (decreasing resistance) due to mechanical boundaries purification. These findings allow optimization of the process for preparation of the alloys with desired electrical conductivity and mechanical properties, specifically for application as electrode materials.
10.1016-j.jallcom.2016.07.210	4	transformation; martensite; martensitic; phase; shape; beta; memory; shape memory; temperature; temperatures; martensitic transformation; gamma; transformation temperatures; effect; thermal	A polycrystalline copper alloy with 13.7 wt% aluminum and 4.0 wt% nickel, produced by plasma fusion followed by injection molding, was investigated for the reversible martensitic transformations (RMT) occurring in association with load-free thermal cycling treatments (TCT's). The as-received quenched alloy was subjected to distinct TCT's up to 500 cycles within the temperature interval from 258 K (below M-f) to 373 K (above A(f)). Each distinct TCT was finished at room temperature (RT) either by half cooling cycle (258 K to RT) or by half heating cycle (373 K to RT). Transformations were characterized by X-ray diffraction, differential scanning calorimetry, optical microscopy and microhardness. The results revealed a complex sequence of transformations involving the high temperature beta(1) phase, the metastable gamma(1)' and beta(1)' martensitic phases, and the intermediate Al7Cu4Ni phase, known as the R phase. Depending on the number of cycles and the finishing way, the sequence of transformations was partial or complete. The RMT with TCT promotes different changes in the microstructure, including an apparent pull out of grains. Microhardness was also sensibly affected owing to the complex participation of different phases.
10.1016-j.jallcom.2016.08.247	-1		Solubility of iron in copper is a key parameter in understanding aging kinetics and electrical conductivity of Cu-Fe alloy. However, the conventional calculation method for solubility, i.e. through calculating the enthalpy and vibrational entropy, has a limit in analyzing iron solubility in ternary Cu-Fe-X alloys, because favorable binding between the alloying element X and Fe may form compounds between Fe and X and lead to the calculation results are higher than the real value. To correct the influence of X-Fe binding energy on the solubility calculated, difference charge density Delta rho and the local densities of states (LDOS) were employed to investigate the binding between Fe and its surrounding Cu atoms after addition of the third element. Based on the previous research, 14 elements including B, Si, P, Al, Ge, S, Mg, Ag, Cd, Sn, In, Sb, Zr and Bi were selected for investigation. Conventional calculations for Fe solubility, difference charge density and the local densities of states between Fe and Cu atoms were carried out in the present work. The results show that decrement in the solubility of Fe in Cu should be significant after addition of 4 alloying elements Ag, Mg, Al and S and the decrement is not obvious for two elements Sb and P, however, eight elements B, In, Si, Ge, Sn, Zr, Bi and Cd have little effect on the solubility of Fe. The calculation results give guides for the composition design of high strength and high conductivity Cu-Fe alloys.
10.1016-j.jallcom.2016.08.303	17	wear; composites; coating; friction; composite; coatings; surface; tribological; properties; wear resistance; resistance; powder; sliding; matrix; wear rate	Graphene nanosheets (GNSs) reinforced pure copper matrix composites were prepared by ball-milling and hot-press sintering. The morphologies and structures of GNSs-Cu powders were studied after ball-milling for different time. The effects of the GNSs content on the microstructures, mechanical properties and fracture mechanisms of the composites were also investigated. It is indicated that the GNSs are gradually dispersed into the copper matrix with increasing the ball-milling time and a uniform dispersion is achieved after ball-milling for 5 h . When the content of GNSs in the composite is 0.5 wt%, GNSs distribute randomly in the composite and the interface bonding is good which is benefit to enhance the mechanical properties of composite. With increasing the GNSs contents, the aggregation of GNSs in the composite is apparent, which seriously separates the matrix and results in low mechanical properties. The fracture mechanism of the composites changes from ductile to brittle.
10.1016-j.jallcom.2016.09.090	-1		A sponge structure featuring a micropore network and nanodendritic wall consisting of Cu-Co oxide core-shell like hybrid nanobranches is reported. First, microporous sponge structure with Cu-Co hybrid nanobranches was formed by hydrogen-templated electrolytic deposition. Next, Cu-Co branches were transformed to Cu-Co(OH)(2) branches by selective anodic oxidation of Co. Cu-CoO branches were then obtained by subsequent thermal dehydration. During the selective anodization and subsequent dehydration of the as-deposited sample, the overall structures of micropore network and core-shell like nanodendritic branches were preserved.
10.1016-j.jallcom.2016.09.318	-1		This paper presents the structural and morphological analysis of various Cu/Zn based nanoparticles evolved from bulk brass under different experimental conditions. Vaporization of bulk brass in a solvated metal atom dispersion (SMAD) method results in dealloying of brass into Zn and Cu atoms. Subsequent in situ nucleation and growth of dealloyed components yields Cu/Zn@Cu core-shell nanocomposites. The behavior of these nanocomposites under different heating conditions is studied in detail. Solid state annealing generates brass nanoparticles going through several phases of Cu-Zn phase diagram such as eta-CuZn5, gamma-Cu5Zn8, beta-CuZn (observed as martensite) and alpha-CuZn in sequence. Whereas, a digestive ripening process which involves refluxing of nanocomposites prepared with capping agents imparts spherical morphology and significantly brings down the size and size distribution of the particles. A detailed characterization of refluxed nanocomposites demonstrates certain processes such as diffusion of Zn atoms and segregation of Cu and Zn phases.
10.1016-j.jallcom.2016.10.060	4	transformation; martensite; martensitic; phase; shape; beta; memory; shape memory; temperature; temperatures; martensitic transformation; gamma; transformation temperatures; effect; thermal	The method for the deconvolution of overlapping DSC peaks here proposed has been used by the first time for the quantitative determination of the enthalpies associated to the phase transitions undergone during the aging of an alloy. They have been determined the enthalpies evolved along the first and the second overlapping DSC traces of Cu-10 wt%Ni-5.5 wt%Sn alloy, which are associated, respectively, to the spinodal decomposition of the alloy and the segregation of a DO22 (CuxNi1-x)(3)Sn tetragonal phase. The fraction of the DO22 phase (responsible of the aging hardening of this alloy) has been successfully determined from DSC as a function of the annealing treatment, while TEM and XRD failed for this purpose. It has been demonstrated that a threshold higher than 50% of crystallization of the DO22 phase is required for achieving a significant increase of the hardness as a function of the crystallization percentage. These results suggest that microcalorimetric measurement can be a powerful tool to establish quantitative relationships between the mechanical, electrical or functional properties of alloys and their structural changes undergone by aging.
10.1016-j.jallcom.2016.10.090	4	transformation; martensite; martensitic; phase; shape; beta; memory; shape memory; temperature; temperatures; martensitic transformation; gamma; transformation temperatures; effect; thermal	The superelastic behavior of single crystal Cu-Al-Mn-Ni shape memory alloy micro-pillars was studied under compression as a function of crystallographic orientation. Cylindrical pillars of about 2 mm diameter were micro-machined from targeted crystal orientations. While pillars oriented close to the [001] direction showed the largest total transformation strain (similar to 7%), plastic deformation dominated the compressive response in the pillars milled close to the [111] direction due to their high elastic anisotropy combined with the large stresses required to induce the transformation. Shape strain contour plots were constructed for gamma' and beta' martensites, and the martensite start stress was calculated using the Clausius-Clapeyron equation. The same general trends are observed in both the experimental and calculated results, with some exceptions: larger transformation stresses and lower transformation strains are observed in the microsized pillars.
10.1016-j.jallcom.2016.10.214	9	magnetic; magnetization; magnetoresistance; temperature; superparamagnetic; annealing; gmr; field; magnetic properties; ferromagnetic; granular; samples; magnetic field; melt-spun; particles	The influence of annealing on structure and temperature and magnetic field dependences of resistance of Cu100-xCox (x = 5, 10, 20) glass-coated microwires prepared using Taylor-Ulitovsky has been studied. All Cu100-xCox microwires present resistivity minimum at certain temperature, T-m. This minimum is very well defined for as-cast samples. T-m-values decrease after annealing (from about 50 K to about 25 K). Observed R(T) dependences and the minimum are well affected by applied magnetic field. Additionally we observed a significant increasing of the GMR effect in the annealed samples (at 400 degrees C) with long enough annealing time (up to 34% GMR effect). Considerable enhancement of the GMR effect related with structural changes of the studied samples is promising for technical applications.
10.1016-j.jallcom.2016.10.302	-1		The Cr phase separation process and kinetics of a metastable Cu(96)C(r)4 alloy film were investigated by isothermal annealing at different temperatures of up to 500 degrees C using transmission electron microscopy. It is shown that the Cr phase separation proceeds predominantly via enrichment of Cr at grain boundaries and grain boundary diffusion. Temperature dependent diffusion coefficients and the activation energy for grain boundary diffusion of Cr in faceecentered cubic Cu are determined from analytical in-situ transmission electron microscopy experiments. In addition, the influence of electron beam irradiation on the diffusion kinetics is considered.
10.1016-j.jallcom.2016.11.014	-1		The mechanical performance of precipitation hardening alloy depends much on the nature of precipitates. For the sake of properties optimization, various precipitation states were designed to clarify the correlation between the precipitation and mechanical properties of a Cu-Be-Co-Ni alloy. The characters of each precipitation state were quantitatively characterized using TEM. Then both tensile and tension-compression (Bauschinger) tests were conducted to investigate the isotropic and kinematic contributions to the work hardening. Based on the quantitative analysis results of the precipitates, a flow stress model with the integration of yield stress, isotropic and kinematic work hardening behavior was established. The model indicates that the strength and ductility are determined by two contradictory factors: the dislocation dynamic recovery rate and dislocation storage rate. Optimization of strength and ductility relies on the balance of these two contradictory factors. Large non-shearable precipitates will increase both the dynamic recovery and the storage rate while fine shearable precipitates will make them decrease simultaneously. It is suggested that the alloy containing the mixture of above two kinds of precipitates will achieve the optimization.
10.1016-j.jallcom.2016.11.085	-1		A Cu-37 at%Ag composite was produced by high-pressure torsion processing of elemental Cu and Ag powders at room temperature. The initial micrometer-sized powder particles were compressed directly in the high-pressure torsion tool and subsequently deformed to different strain levels. The microstructural evolution was studied in detail by scanning and transmission electron microscopy and synchrotron X-Ray measurements, and related to the mechanical properties by microhardness and nanoindentation measurements. The HPT process led to an alignment of Cu and Ag into a lamellar composite microstructure. With increasing applied strain the Cu and Ag lamellae were continuously thinned and simultaneously an ultrafine-grained microstructure was formed in the separate Cu and Ag lamellae. When the lamella spacing reached values lower than the respective grain sizes inside the lamellae, a further lamella thinning occurred causing a significant hardness increase of the composite. At lamella spacings below 50 nm deformation started to localize in 150-300 nm broad shear bands, which surprisingly exhibited no softening. Instead, the steady formation of new shear bands aided to transform the lamellar structure into a nanocrystalline equi-axed microstructure and additionally rotated the lamellar matrix towards the shear plane. This process led to an additional refinement of the alloy and a hardness increase until a constant hardness level was obtained. Combined analyses by synchrotron X-ray and transmission electron microscopy measurements revealed that, after reaching the saturation microhardness level, mechanical mixing of Cu and Ag occurred in the shear bands, which can be attributed to the enormous strains accommodated in the shear bands. Due to the localized deformation by shear bands, structural and chemical homogenization of the alloy was not achieved even at very high applied strains. The final microstructure was composed of nanocrystalline single-phase supersaturated regions embedded in a residual nano-lamellar matrix.
10.1016-j.jallcom.2016.11.114	-1		Cu-Al2O3 composite sheets were prepared by Cu-Al alloy sheet internal oxidation. The Al2O3 precipitation phase was extracted from the Cu-Al2O3 composite sheets. The Cu-Al2O3 composite sheets were melted and then solidified to prepare Cu-Al2O3 bulk composite ingot. The crystal types and distribution of precipitated Al2O3 phase in the Cu-Al2O3 composite sheets and the ingot were investigated. In the Cu -Al2O3 composite sheet, the crystal types of the Al2O3 precipitation phase include gamma-Al2O3 , alpha-Al2O3 and theta-Al2O3. The main gamma-Al2O3 phase has a coherent interface with the Cu matrix, and the amount of alpha-Al2O3 and q-Al2O3 phases decreases from the surface to the bulk. During composite sheets melting, dispersed Al2O3 particles aggregated, and became isolated from the Cu matrix. Most of the gamma-Al2O3 phase was transformed into the gamma-Al2O3 phase.
10.1016-j.jallcom.2016.11.137	-1		High strength Cu-Ni-Si alloys were potential elastic conductive materials due to their high strength and high electrical conductivity. To address the trade-off between strength and electrical conductivity, a combined aging process has been developed to enhance the properties of a Cu-6.0Ni-1.0Si-0.5Al-0.15Mg-0.1Cr alloy after an initial thermo-mechanical heat treatment. The microstructure evolutions of the studied alloys were investigated by optical microscopy, scanning electron microscopy, and transmission electron microscopy. The mechanical and physical properties were evaluated through hardness measurements, tensile test and conductivity test. The results demonstrated that a hardness value of 381 HV, an ultimate strength of 1155.8 MPa, an elongation of 3.5%, and an electrical conductivity of 25.2%IACS were achieved after an appropriate combined aging process. Cold rolling led to the formation of a dense dislocation wall as a result of dynamic interactions among the dislocations and precipitates. During the second stage of aging, nanoscale precipitates formed in the first stage slowly coarsened and effectively pinned dislocations motion. The combined aging process increased the hardness and strength, without sacrificed the electrical conductivity. This work provided an effective route for balancing the strength and electrical conductivity of copper alloys.
10.1016-j.jallcom.2016.11.233	-1		There is an increasing demand for precipitation-hardened Cu-Ni-Si alloys in the industry, where the high strength and moderate electrical conductivity are required. The main objective of this study was to apply a combination of microstructure refinement using swaging (SW) to generate an ultrafine-grained (UFG) microstructure in Cu-2.5 wt% Ni-0.5 wt% Si-0.06 wt% Mg (Cu-2.5Ni-0.5Si-0.06Mg), along with an optimized precipitation hardening. As a result, a substantial improvement of mechanical properties of the swaged samples (UFG condition) after precipitation hardening is apparent as compared to the precipitation-hardened non-swaged samples (coarse-grained (CG) condition). The mechanical properties of the UFG state are significantly superior to those of the CG state, i.e., a sharp increase in the elongation to fracture of 14% and a tensile strength of 800-900 MPa can be achieved. This study summarizes a detailed description of the microstructure after different processing steps using optical microscope (OM), electron channeling contrast imaging (ECCI) methods, and transmission electron microscopy (TEM), and presents the consequences on the most important mechanical properties such as the strength and ductility.
10.1016-j.jallcom.2016.11.425	-1		We present results from density functional theory calculations referring to the magnetic properties of 13, 55, 147 and 309 atoms Cu-Fe icosahedral nanoclusters. Aiming in finding the nanocluster with the optimum magnetic moment (mu(B)) we explored the various sizes considering several compositions and atomic conformations. It came out that configurations with agglomerated Fe atoms inside the Cu-Fe nanoclusters and pure Cu surface shell are energetically favoured as demonstrated e.g. for the Cu49Fe6 with 2.3 mu(B) compared to 2.1 mu(B) of the Fe bcc. The highest magnetic moment, 3.6 mu(B), was found in the Cu12Fe case with the Fe atom located at the surface cell, while 3.18 mu(B) was found for the Cu297Fe12 in a similar configuration having Fe atoms surrounded by Cu that occupy the surface shell's edges. The magnetic moment is mainly due to Fe's spin up-down electronic density of states difference close to the Fermi level (E-F). In particular, the Spin-up Fe d electronic density of states are fully occupied yielding wavefunctions with homogeneous change distribution while the Spin-down is almost unoccupied exhibiting dangling bonding states close to E-F. These results could be used for the design of environmental sustainable smart alloys with superior magnetic properties e.g. by depositing Fe or FeCu on Cu nanoclusters or including new elements that provide the possibility of keeping the Fe Spin up-down electronic occupation difference close to E-F.
10.1016-j.jallcom.2016.12.018	-1		In this work, in situ TiC particles reinforced Cu matrix composites were fabricated by melting-casting method. The synthesized mechanism of TiC in Cu melts and microstructures of prepared composites were investigated. It is found that TiC are synthesized in Cu-Ti melts by the reaction of graphite and soluble Ti. After adding graphite into Cu-Ti melts, Ti will firstly react with graphite on the surface to form small TiC nucleus and then the TiC will further grow by the continuous diffusion of Ti. During the formation process, most of the prepared TiC particles will be separated with graphite and incorporated into the melts. Once TiC particles into melts, they will hardly grow further due to the lack of C element in Cu melts. Since TiC particles will be separated with graphite at different growth stage, TiC with a wide range of size and various morphologies can be obtained. At the same time, some TiC particle may never be broken with the graphite and will grow into different agglomerations or integrate into larger plate-like TiC.
10.1016-j.jallcom.2016.12.031	-1		In this study, we propose a reaction mechanism for atmospherically sintered copper-phosphorus (CueP) alloy electrodes which are expected to replace silver (Ag) electrodes. Structural analysis using transmission electron microscopy (TEM) has revealed that not only copper phosphide (Cu3P) but also copper phosphates of Cu2P2O7, Cu-3(PO4)(2) and Cu2PO4 distributed mainly at the P-concentrated region of the metallic part, where Cu3P distributed before sintering. In addition, the ordered superstructures which have a period based on the specific lattice spacing of Cu3P {002} were newly discovered. From structural analysis, we estimated the mechanisms comprised of the decomposition of Cu3P accompanied by a lack of Cu and P, then formation of metastable phases involving structural vacancies, and eventual transition to the copper phosphates. We also discussed another manner of forming the copper phosphates by the thermo-dynamical approach . Our results may provide a way to reduce the electrical resistivity of Cu-P alloy electrodes by controlling the structures including the deoxidized Cu.
10.1016-j.jallcom.2016.12.057	-1		Severe plastic deformation not only leads to grain refinement but also accelerates mass-transfer and drives phase transformations in these Cu-based alloys. This review is devoted to the dynamic equilibrium between decomposition of (supersaturated) solid solution and dissolution of precipitates during high pressure torsion (HPT) of diluted Cu-based CueX alloys. The precipitation of second phase particles from a solid solution and their dissolution take place simultaneously and compete with each other. During HPT, a certain steady-state concentration C-s of a second component in a solid solution is reached, as if a sample would be annealed at a certain effective temperature T-eff. We found that T-eff linearly increases with increase of activation enthalpy of bulk tracer diffusion H-D. The correlation between activation enthalpy of bulk tracer diffusion H-D and melting temperature T-m of diffusing alloying component has been found for the first time. As a result, T-eff linearly increases with increase of melting temperature T-m of diffusing alloying component as well. The observed correlations allow one for the first time to predict the behaviour and phase transitions in the Cu-based alloys under high pressure torsion.
10.1016-j.jallcom.2016.12.119	-1		This paper investigates the microstructure and properties of Cu-6C powder metallurgy (PM) alloys irradiated by high-current pulse electron beam (HCPEB). After 20-pulsed HCPEB irradiation, the surface was melted completely and the remelted layer was formed in 2-3 mu m thickness, which consisting of ultrafine Cu grains. Within the near irradiated surface, high-density dislocations and vacancy clusters were observed which provide a large amount of paths for carbon atoms to diffuse into Cu matrix, and it leads to the formation of the supersaturated solid solution, causing Cu lattice parameter expansion. In addition, the extreme rapid cycle generated the ultrafine carbon particles at the surface of Cu-6C metallic matrix. The results of microhardness measurements and sliding wear resistance testing indicated that the irradiated sample exhibited better properties than the initial one. The ultrafine carbon particles played an important role in the antifriction properties, which was attributed to the formation of carbonic tribolayer on the hard surface.
10.1016-j.jallcom.2016.12.180	16	wear; composite; composites; powders; milling; particles; powder; wt; sliding; friction; hardness; matrix; mechanical; surface; properties	Copper matrix composites reinforced with TiO2 particles are promising materials widely used as contact materials due to their excellent mechanical and physical properties such as good electrical and thermal conductivity and strength at high temperature. In this research, the novel contact material were prepared by in-situ oxidation of Cu-Ti pre alloyed powders. The morphology of milled powders and microstructure of nano-composite specimens were studied by SEM and TEM. To evaluate mechanical alloying progress of Cu and Ti powders mixture and internal oxidation after Cu2O addition, XRD analysis were carried out. The Physical and mechanical properties results of specimens indicate that the density, specific electrical resistivity, hardness and wear rate values change significantly with amount of TiO2 in Cu matrix. Hardness and specific electrical resistivity increased and density of Cu/TiO2 nano-composites decreased with increasing amount of TiO2 in Cu matrix.
10.1016-j.jallcom.2016.12.352	-1		The influence of Si addition on microstructure and compressive mechanical properties of as-cast (Cu-10Fe)-xSi (x = 0, 2 wt%) alloys has been investigated. The addition of Si leads to the microstructural refinement and the secondary separated phases, as a result of the change of diffusion process and solubility during solidification. Following the evolution of microstructure, the yield strength of the alloys is significantly enhanced from 180 MPa to 285 MPa. Accordingly, it is believed that the addition of only 2 wt% Si on the Cu-10Fe alloy can lead to the microstructural evolution such as the microstructural refinement and the formation of secondary separated phases with significantly improved mechanical properties. In this study, the relationship between microstructural features and mechanical properties will be discussed via hardening effects, such as Hall-Petch strengthening, solid-solution hardening and precipitation hardening effect.
10.1016-j.jallcom.2017.01.101	-1		The precipitation mechanism and microstructure of aged CuCoNiBe alloys have been studied. Two-step increase in the hardness of the material was ascertained and each increase was attributed to the formation of Guinier-Preston (G.P.) zones and precipitation of beryllides utilizing differential thermal analysis (DTA). Composing of different phases capable of precipitation hardening, characterization of the precipitates end up with ternary CoNiBex phase. Detailed FE-SEM analysis revealed that the secondary beryllides responsible for the hardening of the material precipitate inside the primary beryllides which were formed during solidification. Morphology of the precipitates aged at 460 degrees C for 2.5,4 and 24 h was also examined. It was concluded that the precipitates having rod-like morphology for aging 4 h and disk shaped morphology for aging 2.5 and 24 h .
10.1016-j.jallcom.2017.01.355	-1		The microstructure evolution and properties of a typical precipitation strengthened Cu-0.82Cr alloy during continuous extrusion were investigated by means of optical microscopy, transmission electron microscopy, hardness and conductivity measurement. The severe plastic deformation and precipitation behavior of the alloy during deformation were discussed in detail. The results showed that hardness increased firstly until reaching the maximum value of 148 HB in right-angle bending, and then decreased in the extending extrusion zone. Severe deformation and precipitation process occurred during continuous extrusion, and the nano-scale precipitates inhibited the recrystallization in some extent, both of which contributed to the properties of the extruded alloy. The extruded alloy had an average grain size of about 1.5 mu m, and it reached a yield strength, ultra-strength, elongation and electrical conductivity of 292 MPa, 346 MPa, 34% and 77.5% IACS, respectively.
10.1016-j.jallcom.2017.02.018	-1		We report the enhancement of thermoelectric properties in the complex structured Cu-Bi-S pavonite compounds by optimizing the structural configuration through tuning the Bi-site occupancy, and substitutional doping at interstitial Cu sites by Zn. We verify that electronic transport properties depend on the structural deformation by the Bi site occupancy. Furthermore, we demonstrate that the modification of interstitial site ions enables selective control of thermal conductivity and intrinsically low thermal conductivity can be further suppressed by structural optimization without deteriorating electronic transport properties. We propose that understanding of crystal structure as a basic strategy permits the optimization of thermoelectric properties in the complex structures.
10.1016-j.jallcom.2017.03.069	-1		The phase transformation of a Cu-0.71 wt% Cr alloy during the aging process at 450 degrees C was investigated by Transmission electron microscopy (TEM) and High-resolution transmission electron microscopy (HRTEM) in the study. The strengthening mechanism was studied as well. The precipitation sequence of Cu-0.71 wt% Cr aged at 450 degrees C is supersaturated solid sloution -> G. P zones (fcc Cr-rich phase) -> fcc Cr phase -> order fcc Cr phase -> bcc Cr phase. This transformation can be achieved by the nucleation of coherent fcc spherical precipitates and growth and transformation of fcc precipitates into the bcc structure. When the specimen is aged aging for 1 h-24 h, both fcc and bcc precipitates exist in the matrix simultaneously. Ordering process is found during the aging process, which is in favor of the precipitation of Cr-rich phases. The orientation relationship between bcc Cr precipitates and the matrix exhibit NW-OR. The peak strength effect occurs after aging for about 8 h and the strength continues to decrease with prolonging aging time, indicating overaging.The strengthening effect of Cr-rich phase precipitated in aging at 450 degrees C for 8 h is calculated to be 146 MPa on the basic of the Orowan strengthening mechanism, which is in quite accordance with the experimental data (144.5 MPa).
10.1016-j.jallcom.2017.03.077	-1		The solid-liquid interfacial free energy gamma and its anisotropy in the Cu-Ni binary system were measured by using molecular dynamics simulations coupled with the capillary fluctuation method (CFM) based on an embedded atom method potential. It is found that both the interfacial energy and its anisotropy are enhanced with the increasing of the coexisting temperature, significant variations are however observed in the anisotropy parameters. Nonetheless, the anisotropy relationship is hardly modified, and the inequality gamma(100) > gamma(110) > gamma(111) holds for all temperatures studied. By projecting the calculated anisotropy parameter epsilon 1 and epsilon 2 onto the dendrite growth direction selection map, one finds that a <100> dendrite is generally favored for the Cu-Ni alloys. Upon alloying, the preferred dendrite growth direction shifts to the vicinity of the boundary between the <100> and hyper-branched regions, indicating the possibility of a transition of solidification morphology from a <100> dendrite dominated to a hyper-branched one. These predictions agree well with and explain the experimental observations during the equilibrium and non-equilibrium solidifications in the Cu-Ni alloy systems.
10.1016-j.jallcom.2017.03.106	-1		The microstructure, nanoindentation hardness of the sputtering deposited Cu-Ta films were investigated. Because of high hardness of Ta, the hardness of Cu-Ta films increases with Ta content, except for a platform in the range of 20 at% similar to 60 at% Ta that being related to the amorphous structure. This abnormal behavior presents that the hardness of Cu-Ta films is independent of alloy elemental content in the amorphous structure. The Ta addition inducing to Cu-Ta hardening is counteracted by the increase of inter-atomic distance in the amorphous structure with increasing of Ta. So this opposite effect makes the hardness platform.
10.1016-j.jallcom.2017.03.153	16	wear; composite; composites; powders; milling; particles; powder; wt; sliding; friction; hardness; matrix; mechanical; surface; properties	In the present research work, novel (Cu-10Zn)(100-x) -x wt% Al2O3 (x = 0, 3, 6, 9 & 12) nanocomposites were manufactured by mechanical alloying process followed by vacuum hot-pressing technique. The mechanical properties (sinterability, hardness and compressive strength), wear behavior (coefficient of friction, wear rate and worn surface morphology) and machining behavior (surface roughness and chip thickness) were explained and investigated elaborately. The same compositions of (Cu-10Zn)(100-x) -x wt% Al2O3 microcomposites (coarse crystalline matrix alloy reinforced with alumina) were also fabricated and compared with nanocomposites. It was observed that uniform distribution and embedding of nano-alumina in the nanocrystallite (nano-grain) matrix in nanocomposites were achieved which exhibited excellent performances. The (Cu-10Zn)(88)-12 wt% Al2O3 bulk nanocomposite produced highest compressive strength which was around 9.4 times higher than the same amount of reinforcement of microcomposites. Further, nanocomposites showed lower value of coefficient of friction and surface roughness which means a considerable wear resistance and good surface finish was obtained in nanocomposites.
10.1016-j.jallcom.2017.04.097	2	corrosion; surface; film; electrochemical; films; spectroscopy; layer; current; solution; potential; resistance; composition; x-ray; ions; showed	Cu-Zn-S having inexpensive, non-toxic, and earth-abundant constituent elements, combined with suitable optical and electrical properties is a promising candidate as an absorber material for thin film solar cell fabrication. We report the deposition of Cu-Zn-S thin films using Successive Ionic Layer Adsorption and Reaction (SILAR) method under room temperature and atmospheric conditions. Cu-Zn-S thin films are deposited over glass substrates with different Cu/(Cu+Zn) ratio in the precursor solution to investigate the band gap tunability. The as-deposited Cu-Zn-S films are characterized for determining their structural, compositional, morphological, optical and electrical properties. Also studied the stability of electrical properties for a period of six months after the deposition. All the films exhibited p-type conductivity and a relatively high absorption coefficient value between 10(4) to 10(5) cm(-1) in the visible and near-IR spectral range. We observed that, under the Zn-rich growth conditions, the films formed are having a double band gap structure with lower band gap values in the range 1.6-1.7 eV, making them a suitable absorber material for solar cell fabrication. Under the Cu-rich growth conditions, band gap values reached 2.4-2.6 eV making them a suitable buffer/window layer in solar cell application. Notably, films with Cu/(Cu+Zn) ratio 0.8 showed an optical transparency of 40-70% in the visible spectrum along with an electrical conductivity of 2900 S cm(-1), which is much higher than the other reported p-type transparent conducting materials.
10.1016-j.jallcom.2017.04.234	1	shape; memory; shape memory; damping; martensite; martensitic; damping capacity; transformation; capacity; strain; superelasticity; temperature; cu-al-mn; shape memory effect; effect	Our previous study developed a polycrystalline Cu-Al-Ni alloy by directional solidification, which exhibits excellent superelasticity. To further verify the application feasibility of the Cu-Al-Ni alloy, cyclic superelastic behaviors of the alloy under varying loading frequencies and strain amplitudes were investigated in this study. The results show that the superelasticity of the polycrystalline Cu-Al-Ni alloy has ultra-low dependence on loading frequency in a range of 0.005 similar to 5 Hz. The alloy can sustain over 2000 tensile cycles at the applied total strain of 4%, exhibiting 1750 cycles and 825 cycles for total strain of 6% and 8%, respectively. The normalized critical stress and strain vary only similar to 10% and similar to 0.03% after 2000 times of loading-unloading with a strain amplitude of 4%. Compared with the commercial polycrystalline Ni-Ti alloy, the directionally solidified Cu-Al-Ni alloys with columnar grains exhibit excellent cyclic stress-strain response and fatigue life, which are promising materials for energy absorption and seismic protection structures or components.
10.1016-j.jallcom.2017.05.093	-1		Nanocrystalline Cu12 at% Al alloy was synthesized by high energy ball milling under cryogenic condition. The alloy was then annealed up to 900 degrees C (or 0.87 T-m). Phase and microstructural evaluation were carried out by X-ray diffraction (XRD), transmission electron microscopy (TEM) and the mechanical property was investigated by microhardness testing. Results show that at elevated temperatures grain growth of Cu 12 at% Al alloy is much less than pure Cu prepared under same condition. The microhardness of the alloy decreases from 2.91 GPa to 2.73 GPa (similar to 6% decrease) after annealing at 900 degrees C. Superior thermal stability at high temperature was ascribed to the grain boundary pinning by nano-scale intermetallic particles. Kinetically stabilized grain size and hardness show good agreement with theoretical predictions.
10.1016-j.jallcom.2017.05.117	16	wear; composite; composites; powders; milling; particles; powder; wt; sliding; friction; hardness; matrix; mechanical; surface; properties	Rice husk ash (RHA) is an economical reinforcement to improve the poor wear behavior of pure copper. This work concentrates on the preparation of Cu/RHA (0,6,12,18 vol.%) copper matrix composites (CMCs) by friction stir processing (FSP). Grooves were machined on the copper plates to deposit RHA particles and were friction stir processed at a chosen set of process parameters. The microstructure was studied using optical, scanning and transmission electron microscopy. The wear behavior was estimated using a pin-on-disc apparatus. The micrographs revealed a uniform dispersion of RHA particles in the copper matrix. Neither aggregation nor segregation was observed. The variation in the dispersion of RHA particles at different regions within the stir zone was negligible. A good interfacial bonding between RHA particles and the copper matrix was realized. Many RHA particles encountered break up. A remarkable grain refinement was achieved due to dynamic recrystallization and pinning effect of RHA particles. The wear behavior under dry sliding condition was presented in detail.
10.1016-j.jallcom.2017.05.127	-1		The compression deformation behavior of the Cu-15Ni-8Sn alloy prepared by powder metallurgy was investigated under a temperature range from 300 to 573 K and a strain rate range of 5 x 10(-5) similar to 1 x 10(-2) s(-1). The results showed that in a certain range of strain rates and temperatures, the stress-strain curve exhibited obvious serrated flows which were induced by dynamic strain aging (DSA). The activation energy calculations indicated that the DSA was mainly attributed to the interaction of Sn solute atoms with dislocations. In the microstructure of the alloy pre-deformed in the region of DSA, Sn atoms were more likely to aggregated along the slip bands and therefore resulted in the dynamic precipitation of Sn-rich phase at lower temperature than that of natural aging alloy without pre-deformation. (C) 2017 Published by Elsevier B.V.
10.1016-j.jallcom.2017.05.244	-1		Coppereiron alloys (CFAs) are a much anticipated class of materials for electrical contacts, magnetic recordings, and sensors. In this study, Cu100-Fe-x(x) alloys (x = 10, 30,or 50, representative of the Fe content in at%) were prepared via gas atomization, followed by sintering and heat treatment in vacuum. The electrical conductivity of the alloys was determined as a function of the grain size. The substitutional solid solution formed between copper and iron during alloy synthesis is decomposed during the subsequent heat treatment, followed by sluggish grain growth in samples of all compositions, but it was highest in the sample consisting of 10 at% of iron. In the samples with the other two compositions, grain growth was very slow and the grain boundaries were pinned by the Fe-rich phase. Bulk samples of all compositions with powder particles measuring similar to 24 mm exhibited higher electrical conductivity with longer durations of heat treatment.
10.1016-j.jallcom.2017.06.012	-1		Different Cu-Zr alloys were hydrogenated under 100 bars of hydrogen pressure at different temperatures. The hydrogenation induced transformation of the initially amorphous phase into a polycrystalline structure characterized by its nanoscale (<5 nm), mostly composed of metallic Cu and ZrH2. Calorimetry measurements after hydrogenation showed a low temperature exothermic transformation occurring in the alloys hydrogenated at temperatures below 473 K, followed by multiple endothermic peaks at higher temperature attributed to dehydrogenation of different hydride phases. Activation barrier energies of the phase transformation were derived from Kissinger's method, and further characterization involving transmission electron microscopy revealed the existence of delta ZrH2 with cubic structure contrasting with the typical epsilon ZrH2 with tetragonal structure. This study evidences the effect of hydrogen pressure, temperature, and the alloy chemistry on the nature of the hydride formation in Cu-Zr binary amorphous alloys during the hydrogenation procedure.
10.1016-j.jallcom.2017.06.155	15	aging; strength; conductivity; electrical conductivity; electrical; mpa; treatment; strengthening; degrees; cu-; cold; precipitation; tensile strength; tensile; iacs	The contact wires in high-speed railway industry should have high strength, high electrical conductivity, and high industrial manufacturing feasibility. An economical Cu-0.29Mg-0.21Ca (wt%) alloy has been designed and synthesized by non-vacuum melting and casting followed by thermal-mechanical treatments. Microstructure evolutions and mechanical properties of the studied alloy were investigated systematically. Microstructure observations showed that after cold deformation, the initial grain size was significantly refined into small grains full of sub-structures with an average size of 400 nm. After homogenized at 780 degrees C for 1 h, followed by cold rolling reduction of 80%, then annealed at 200 degrees C for 1 h, properties measurements revealed that the studied alloy had outstanding comprehensive performance with an ultimate tensile strength of 545 MPa, a yield strength of 526 MPa, an elongation of 3.60%, and an electrical conductivity of 71.79%IACS. The high electrical conductivity was due to the addition of Ca which purified the copper matrix through reacting with some impurity elements and caused little electron scattering. The high strength was attributed to the dispersion strengthening, solid solution strengthening, sub-structure strengthening, and dislocation strengthening, in which sub-structure strengthening is dominate.
10.1016-j.jallcom.2017.06.176	-1		In present study, Cu-Al2O3 composites with both higher micro-hardness and electrical conductivity were fabricated by internal-oxidizing Cu-Al and Cu-Al-Ag sheets at 950 degrees C for 2 h . A small amount of Ag was doped as additives with atomic ratio of Ag/Al ranging from 0 to 0.25. Effects of Ag addition on microstructures, electrical conductivity and micro-hardness were investigated. Results show that the morphology and size distribution of Al2O3 in internal-oxidized Cu-Al alloys were highly sensitive to Ag addition. The size of Al2O3 precipitates decreased from similar to 63 nm to similar to 37 nm when increasing Ag content. Moreover, a large number of triangular Al2O3 precipitate with similar size was observed by field emission scanning electron microscope (FESEM) and high-resolution transmission electron microscopy (HRTEM) in Ag-doped Cu-Al2O3 composites. The orientation relationship between triangular Al2O3 and Cu matrix was [112](Cu)//[110](Al2O3), (11 (1) over bar)(Cu)//(002)(Al2O3) and (2 (2) over bar 0)(Cu)//(2 (2) over bar 0)(Al2O3). Increasing the amount of Ag enhances the electrical conductivity and mechanical strength simultaneously. The optimal electrical and mechanical properties which were 85.9% IACS and 162 HV respectively, were obtained when atomic ratio of Ag/Al was similar to 1: 4 in internal-oxidized Cu- Al2O3-Ag alloy.
10.1016-j.jallcom.2017.06.312	4	transformation; martensite; martensitic; phase; shape; beta; memory; shape memory; temperature; temperatures; martensitic transformation; gamma; transformation temperatures; effect; thermal	The behaviour of the martensitic phase transformation of a Cu-Al-Ni-Mn shape memory alloy was studied for as-atomized and heat-treated powders. X-ray diffraction, microscopy techniques and thermodynamic calculations were used to understand the different transformation behaviour observed during differential scanning calorimetry (DSC) analysis. Two overlapped transformation peaks were observed in the DSC curves for the as-atomized powder. After annealing, the peaks progressively became only single peak when the annealing temperature and time were increased. No difference in phase formation and microstructure was observed by X-ray diffraction and scanning electron microscopy when compared as-atomized and annealed powders, although transmission electron microscopy analyses showed that the as-cast powders had more dislocations trapped in the microstructure than the annealed samples. Considering the experimental results and thermodynamic considerations, it was concluded that the smooth double peak effect in the as-atomized powders occurred due to a different state of internal stresses and elastic energy accumulation during forward transformation. The absence of this effect after heat treatment shows that the internal stresses and defects were annihilated after annealing, changing the elastic energy accumulation and the transformation behaviour. Understanding the martensitic transformation on Cu-Al-Ni-Mn powders is important considering the potential use of powder metallurgy processing route.
10.1016-j.jallcom.2017.07.200	-1		In this study, severe plastic deformation by high-pressure torsion is used as a fabrication method for nanocrystalline magnetic Cu-Co alloys in bulk quantities. By subsequent isothermal annealing, phase separation of the supersaturated solid solutions can be obtained. The magnetic properties of the as-processed and annealed materials have been studied systematically and correlated to the evolving nanostructures investigated in detail by transmission electron microscopy and atom probe tomography. By additional high-pressure torsion deformation at liquid nitrogen temperature the magnetic properties of the Cu74Co26 alloy can be further tuned.
10.1016-j.jallcom.2017.07.205	-1		The roll bonding process facilitates the top-down approach to the fabrication of multilayered alloys and composites from unusual combinations of metals. We demonstrate the application of the roll bonding process to produce trimetallic Cu/Sn/Zn layered cladding with strong interfaces at room temperature. Room temperature tensile response of the trimetallic layered clad involves a two-stage deformation behavior with typical composite strengthening. Microstructural analysis suggests that dynamic deformation activities such occurring in Sn can control the tensile behavior of the trimetallic claddings.
10.1016-j.jallcom.2017.07.297	-1		Micron-sized CNTS/CU2O composite powder prepared by Molecular Level Mixing (MLM) was mixed with flaked Cu-1.0 wt% Ti (Cu-1.0 Ti) matrix powders by low-energy ball milling. After reduction and hot pressing, CNTs/Cu-Ti composites were fabricated. Microstructure and mechanical properties of the composites were characterized by SEM, EDS, HRTEM, hardness and tensile tests, etc. The results showed that mechanical properties of the CNTs/Cu-Ti composites were enhanced compared with alloy matrix, which were ascribed to the well-distributed of CNTs and strong bonding interface with the matrix by the formation of a transition layer of TiC. Finally, strengthening mechanisms were discussed. (C) 2017 Elsevier B.V. All rights reserved
10.1016-j.jallcom.2017.07.332	-1		Stacking-fault energy (SFE) is a critical parameter that influences plastic deformation of Cu alloys. Here, the SFEs of Cu solid solutions at various temperatures and solute concentrations were studied by using first-principles calculations. The interaction energies of 18 substitutional atoms and 5 interstitial atoms with stacking fault (SF) in Cu were obtained for the first time. The results show that the interactions can extend to the second layer with respect to the SF. Substitutional atoms Sn, Al, Zn, P, Si, Ge as well as interstitial atoms Be, C, N, O, H have large attraction energies with the SF; whereas, substitutional atoms Ti, Mn, Cr are repelled by the SF, and the rest of the atoms have small interaction energies. Then, the effects of uniform and Fermi-Dirac distribution of solute atoms on the SFE of Cu alloys were further investigated based on these interaction energies. It is found that the SFE of Cu can be drastically reduced by Sn, Al, Zn, P, Si, Ge, C, N and 0 atoms with relatively high concentration at low temperatures. Our research suggests that it is possible to obtain twins in bulk Cu by adding alloying elements at circumstances, since the SFEs can be significantly lowered. (C) 2017 Elsevier B.V. All rights reserved
10.1016-j.jallcom.2017.09.109	-1		The strengthening precipitates in a Cu-Ni-P alloy have been investigated using aberration-corrected transmission electron microscope. It is found that coherent plate-shaped particles with hexagonal Ni2P (h-Ni2P) structure are mainly responsible for the hardness of this alloy. The orientation relationship between h-Ni2P precipitates and the matrix should be revised as (111)(Cu)//(1 (2) over bar 11)(h), [1 $(1) over bar0](Cu)//[10 $(1) over bar0](h) and [11 $(2) over bar](Cu)//[1 $$(2) over bar1 $(6) over bar](h), and the habit plane of them is parallel to the {111}(Cu). Both the morphological and crystallographic characteristics of the h-Ni2P precipitates can be explained by classical theories of phase transformation.
10.1016-j.jallcom.2017.09.121	-1		The influence of microstructure on the Young's modulus and hardness in a Cu-2Be (wt%) alloy was analyzed. The material was homogenized at 1113 K and submitted to thermal aging at different times and temperatures between 540 and 680 K. The improvement of the mechanical properties of the material, with an increase of the hardness and Young's modulus is mainly due to the formation of metastable phases in the a matrix. For temperatures up to 623 K, the formation of gamma precipitates produces an increase of the hardness in an early stage. At 676 K, the maximum hardness is reached for 0.75 h due to the presence of gamma' phase, and further aging times induce a softening of the material. The Young's modulus curves present a similar behavior respect to the hardness curves. However, no significant variation of the modulus was found for aging longer than 1 h at 676 K. Then, only the size and shape and not the change in the orientation of the precipitates would have influence on the value of the modulus. A micromechanical model was applied, and the volume fraction curves of precipitates were estimated from E modulus. For the aging temperature of 676 K and times longer than 1 h, the modulus is almost constant because there is no increase in the fraction of precipitates and their maximum volume fraction is reached.
10.1016-j.jallcom.2017.09.132	-1		A Cu-Ni-Si-Cr + Al2O3 alloy, which combines the precipitation and dispersion hardening of the alloy, were produced by using the powder metallurgy (P/M) technique. To obtain the optimal properties of the alloy, a series of solution and aging treatments were conducted. Following heat treatments, the microstructural, thermal and mechanical properties of P/M produced Cu-Ni-Si-Cr + Al2O3 alloy were investigated. The microstructural investigation indicates that the as hot-forged P/M Cu-Ni-Si-Cr + Al2O3 alloy consists of Cu-Ni-Si-Cr powder (considered as grain A) and Cu-Al2O3 powder (considered as grain B). After heat treatments, it is observed that massive Ni and minor Si elements from grain A diffuse to grain B and react with each other, resulting in the formation of the beta-Ni3Si strengthening phases in both grains. Also, Al2O3 dispersoids, which disperse in grain B, provide the high thermal stability in grain size. Therefore, the P/M-produced copper alloy developed in this study has a combination of the better thermal stability in relation to grain size, high strength or hardness and high thermal conductivity, which offers possible applications at elevated temperatures.
10.1016-j.jallcom.2017.10.180	16	wear; composite; composites; powders; milling; particles; powder; wt; sliding; friction; hardness; matrix; mechanical; surface; properties	Coppereiron alloys (CFAs) with composition CFA(X); x = 10, 30 and 50 at% Fe were prepared by gas atomization process, sintered and heat treated in vacuum. Rapid solidification and the incorporation of Fe into Cu hint at strain generation in the lattice bringing changes in electrical conductivity. The origin of this strain is discussed using structural and electrical properties. The substitutional solid solution formed between Cu and Fe due to rapid solidification was decomposed during heat treatment in all the three compositions, followed by the increase in Fe particle size, decrease in lattice strain and increase in electrical conductivity.
10.1016-j.jallcom.2017.10.211	16	wear; composite; composites; powders; milling; particles; powder; wt; sliding; friction; hardness; matrix; mechanical; surface; properties	In this work, nanostructured Cu/Al/Mn multilayered composites were successfully fabricated by the accumulative roll bonding (ARB) method. The microstructure of the produced composites was studied by X-ray diffraction and scanning electron microscopy. Also, the hardness, tensile and corrosion behaviors of the composites were studied as a function of ARB cycles. It was observed that by increasing the number of ARB cycles, the thickness of the Al layers is decreased from 0.3 mu m to 0.25 mm, where a Cu-matrix, Al/ Mn-reinforced, multilayered composite with homogeneously distributed Al layers and Mn particles was achieved after nine ARB cycles. Also, the results revealed the development of nanostructures with the mean crystallite size of about 50 nm in the produced composites. According to the tensile experiments, by increasing ARB cycles, the strength of the composites was increased and reached 420.8 MPa. The electrochemical corrosion behavior of the produced composites was also investigated in a 3.5 wt% NaCl solution by a potentiostat-galvanostat device. It was found that the corrosion rate of the composite is increased by increasing ARB cycles from 5 mu A/cm(2) to 12.2 mu A/cm(2) and then decreased to 9.5 mu A/cm(2).
10.1016-j.jallcom.2017.10.279	-1		In this study, titanium was introduced to a Cu-Si alloy as an impurity getter to redistribute boron. A small amount of Ti was melted with Cu-Si alloy, followed by cooling of the alloy to precipitate purified Si crystals which were later separated through multi-step leaching. The effects of Ti content on the distribution of various elements in different phases and microstructure of the solidified alloy were investigated. It was found that Ti in Cu-Si alloy facilitates boron removal by several mechanisms including formation of TiB2 and decreasing the segregation coefficient of B between Si and Cu-Si. Addition of Ti to a Cu-50 wt% Si alloy, compared to silicon metal, showed a significant increase in B removal. An increase in Ti in the range of 1-5% increased B removal, reaching similar to 85% at 5% Ti addition. Ti in excess of that required to form TiB2 reacts with Si to generate TiSi2, which collects impurities such as P and Al.
10.1016-j.jallcom.2017.10.282	-1		In this paper, Cu-1wt%Cr and Cu-1wt%Cr/5wt%CNT nanocomposite powders were produced by mechanical alloying method. Then, nanocomposite samples were consolidated by hot pressing at different temperatures of 25, 300 and 500 degrees C, times of 30, 60, 90 and 120 s and pressures of 40, 80 and 120 MPa. The consolidated nanocomposite samples were characterized by X-ray diffraction, scanning electron microscopy, shear punch test, wear test and measurements of density, microhardness and thermal stability. It was found that pressing temperature has a significant effect on improvement of hardness by about 65%. A quantitative relationship between relative density and pressing pressure was proposed. The effects of CNTs addition on the consolidation behavior and characteristics of the consolidated samples were also investigated. The results showed that the addition of CNTs makes the relative density, hardness, shear strength and elongation to failure decrease. However, in the presence of CNTs, the friction coefficient decreased by 82%; therefore, the wear resistance of the Cu-1wt%Cr/5wt%CNT nanocomposite was 72% higher than that of the Cu-1wt%Cr. Additionally, presence of 5wt% CNTs led to a four times greater thermal stability.
10.1016-j.jallcom.2017.11.129	-1		This study assessed the electrical conductivity and the mechanical properties of pure Cu, 1 and 2.6 mass % Ti additions in a composition of CuTi0.014 and CuTi0.035 in region of Cu-solid solution, with the aim of studying the effect of titanium additions on the properties of copper. A sample of pure Cu, CuTi0.014 and CuTi0.035 were prepared in a plastic canister and mixed with alumina balls for 3 h at 49 rpm. The powdered samples were sintered at a temperature of 650 degrees C, with a punch load of 50 MPa, a dwelling time of 5 min and a heating rate of 50 degrees C/min. The results showed that the electrical conductivity of Cu, CuTi0.014 and CuTi0.035 are: 4.8, 5.0 and 4.2 (S/m) at temperatures of 345, 550 and 319 degrees C, respectively. The relative densities of the sintered samples are 96.76, 96.30 and 86.33% for Cu, CuTi0.014 and CuTi0.035, respectively. The Vickers hardness data of the sintered samples show that CuTi0.035 has the highest value (similar to 749 MPa), followed by CuTi0.014 (similar to 724 MPa) and pure Cu with (similar to 645 MPa). In addition, the predicted yield strength (YS) and ultimate tensile strength (UTS) of the sintered samples were investigated. The YS are 1604, 1552 and 1395 MPa for CuTi0.035, CuTi0.014 and Cu, respectively. In similar other, the UTS are 1318, 1285 and 1182 MPa. The addition of 1 and 2.6 mass % Ti improved the corrosion resistivity of Cu in H2SO4 acid environment. Also, the addition of the 2.6 and mass % of Ti increases the coefficient of friction of Cu under dry sliding condition with a load of 25 N. The microstructures of the sintered CuTi0.014 and CuTi0.035 showed the precipitation of Ti. However, CuTi0.014 alloy has the best properties and is an ideal candidate for elevated temperature application. This composition of CuTi alloys can be used in the areas where Cu is required to maintain good electrical and mechanical properties at elevated temperatures (above room temperature) applications.
10.1016-j.jallcom.2017.11.176	16	wear; composite; composites; powders; milling; particles; powder; wt; sliding; friction; hardness; matrix; mechanical; surface; properties	In this study, Cu-10 wt% Al-X wt% Ag alloys (X = 0.0, 2.0, 2.5, 3.0, 4.0, 5.0, 5.5, 6.0) were synthesized through Powder Metallurgy. The effect of silver addition on microstructural, thermal and mechanical properties of the prepared alloys were investigated by using Scanning Electron Microscopy (SEM), Energy Dispersion Spectroscopy (EDS), X-rays Diffractometry (XRD), Transient Plane Source method (TPS), Rockwell hardness tester and Universal testing Machines. The XRD result of raw materials such as pure copper, pure aluminum, pure silver were qualified through JCPDS cards, and subsequently quantified. The microstructural analysis of all samples was carried out, with heating rate of 5 C/min and annealed at room temperature. The results indicated that presence of silver in Cu-Al alloy offered better hardness up-to 3% Ag and compression strength increases up to 2% Ag in Cu-10 wt. %Al alloys which shows intermetallic structure in XRD analysis. Thermal conductivity and thermal diffusivity of the prepared alloys are investigated with help of TPS method in this work. It is observed that both thermal conductivity and thermal diffusivity increased with the increase of silver contents in the alloys owing to higher conductive behavior of silver.
10.1016-j.jallcom.2017.11.237	-1		In this work, the microstructure and phase formation in binary Cu-Sn and ternary Cu-Sn-Ti alloys under rapid solidification conditions are studied as a function of alloy composition and cooling rate and compared to the results from solidification at low cooling rate in a Differential Scanning Calorimetry furnace. At high cooling rates (10(3)-10(4) K/s) a metastable Cu5.6Sn phase is observed in all selected binary alloys, which could be explained to have formed via diffusionless martensitic transformation from the parent beta phase. An increasing amount of Sn results in the transition of preferential phase formation in the sequence of alpha, Cu5.6Sn and delta. In the ternary alloys, Ti is observed to form (Cu, Sn )(3)Ti-5 compound at both low and high cooling rates due to the low solubility of Ti in the a phase, and the fraction of (Cu, Sn)(3)Ti-5 and a phases tend to increase with increasing Ti amount but that of Cu5.6Sn decreases. The results are of relevance for the development and optimization of Cu-Sn based alloys for processing techniques involving rapid solidification with varying cooling rates, e.g. laser additive manufacturing.
10.1016-j.jallcom.2017.11.255	-1		CNTs/Cu composite powders were fabricated using an electrodeposition process, and consolidated by hot pressing followed by cold rolling. The electrodeposition is a promising method to obtain homogeneously dispersed CNTs/Cu powders in terms of effective control of CNTs content and particle size of powders during the process. The effects of Cu ions concentration in electrolyte on the dispersion and content of CNTs in powders, particle size, and properties of composites were studied. The electrodeposited CNTs/Cu powders show large amount of embedded CNTs that are strongly bonded with the Cu matrix, and a CNTs network architecture formed in the Cu grains. The particle size 52.72 mu m of powders is obtained at Cu ions concentration of 10 g/L in electrolyte. The tensile strength and electrical conductivity of consolidated CNTs/Cu composites are about 418 MPa and more than 90 +/- 0.16% IACS, respectively. The CNTs network is beneficial to load transfer efficiency and bridge linking for improving strength, but also provides electron transport pathways for high electrical conductivity.
10.1016-j.jallcom.2017.11.273	-1		A gas pressure infiltration method was used to prepare diamond particles reinforced Cu-B alloy matrix composites (Cu-xB/diamond, x = 0.3 and 1.0 wt%). The Raman spectroscopy and X-ray diffraction (XRD) analysis confirm the formation of boron carbide (B4C) at the Cu/diamond interface. The amount of interfacial boron carbide increases with increasing boron content in the Cu matrix. A high thermal conductivity of 868 W/mK and corresponding coefficient of thermal expansion of 5.3 x 10(-6)/K are obtained in the Cu-0.3 wt%B/diamond composite. When the boron content increases to 1.0 wt% B, the thermal conductivity decreases to 647 W/mK. It is found that boron carbide plays a critical role in improving the interfacial bonding and enhancing the thermal conductivity of the Cu-B/diamond composites; however, too much interfacial boron carbide will deteriorate the thermal conductivity of the composites.
10.1016-j.jallcom.2017.12.196	-1		Metal matrix composites are currently being investigated for thermal management applications. In the case of a copper/carbon (Cu/C) composite system, a particular issue is the lack of affinity between the Cu matrix and the C reinforcements. Titanium-alloyed Cu (Cu-Ti) powders were introduced in a Cu/C powder mixture and sintered under load at a temperature at which the Cu-Ti powders became liquid, while the rest of the Cu and C remained solid. Fully dense materials were obtained (porosity of less than 5%). The creation of regular and homogeneous interphases was confirmed. All Ti reacted with the carbon, hence purifying the Cu matrix. Thermal conductivities were enhanced as compared with the Cu/C composites without interphase. The chemical analyses are in agreement with thermodynamic simulations carried out to predict the phase transformation during the sintering process.
10.1016-j.jallcom.2018.01.184	-1		A Cu-Fe-Cr-Si-C immiscible nanocomposite has been produced via laser induction hybrid cladding (LIHC) as a result of liquid-liquid phase transformation. The nanocomposite has a bilayer structure composed of many nanoscaled ferromagnetic (FM) alpha-Fe(Si) particles (similar to 50 nm) embedded within the Cu-rich epsilon-Cu matrix in the upper layer, and large amounts of nanoscaled Cu-rich epsilon-Cu particles (similar to 30 nm) dispersed within FM alpha-Fe(Si) matrix in the lower layer. As a result, the nanocomposite exhibits an enhanced bilayer-microhardness and a comparative corrosion resistance to pure copper produced by LIHC. Interestingly, the nanocomposite also presents a relatively high saturated magnetization (similar to 84.6 emu/g), a low coercivity (similar to 0.65 Oe), and a sudden jump of magnetization at similar to 310 K during heating.
10.1016-j.jallcom.2018.01.218	-1		The effect of high intensity ultrasonic treatment (HIUST) at different pouring temperatures for the application time of 100 s on microstructural modification and hardness of a nickel-aluminum bronze ( NAB) alloy has been studied. The chemical composition of the investigated alloy is Cu-10Al-5Fe-5Ni. The results show clearly that in the absence of HIUST, the coarser dendritic alpha(Cu) phases and coarser beta' phases are formed with a nonuniform distribution of coarser intermetallic k(II) phase particles which are based on Fe3Al in the interdendritic regions. Upon HIUST of this alloy during solidification process, finer equiaxed alpha(Cu) phases and finer beta ' phases with a uniform distribution of finer intermetallic k(II) phase particles along the cast structure can be obtained at optimum pouring temperature of 1090 degrees C. The highest hardness of ultrasonic treated alloy can be achieved at the optimum pouring temperature of 1090 degrees C. The refinement and modification mechanisms resulting in development of microstructure are also investigated.
10.1016-j.jallcom.2018.01.245	16	wear; composite; composites; powders; milling; particles; powder; wt; sliding; friction; hardness; matrix; mechanical; surface; properties	Powders of copper-iron alloys with composition of 10, 30 and 50 at% Fe were prepared by gas atomization process, sintered by Spark Plasma Sintering. The analysis of the as synthesized sample shows two phase FCC-Cu and BCC-Fe structure in all the three compositions independent of powder size. However, solid solution was formed between Cu and Fe during rapid solidification stages. Samples of CFA measuring <= 24 mm exhibited higher magnetic saturation (Ms) as compared to larger powder particles of the same composition due to the presence of enhanced amount of solid solution. With the increase in Fe contents, Ms and coercivity of the alloy both increase.
10.1016-j.jallcom.2018.01.301	-1		Copper-manganese alloy has been established to improve resistance toward electromigration for interconnects. In this work, we employ a deep eutectic solvent (DES) to formulate a nonaqueous electrolyte for pulse current electrodeposition of Cu-Mn alloyed film. Using impedance spectroscopy to record ionic conductivities of DES-based electrolytes, we determine the optimized bath with a Cu/Mn molar ratio of 1:20. We produce an uniform, smooth, and composition-controllable CuMn alloyed film after exploring various pulsing parameters. Signals from X-ray diffractometer (XRD) suggest successful alloying of Cu and Mn with minor presence of MnO2. Profiles from X-ray photoelectron spectroscopy (XPS) validate the metallic nature of Mn from the as-deposited film. Upon Ar annealing, both XRD and XPS exhibit strong signals of MnO2 formation. In addition, images from transmission electron microscope and qualitative elemental chemical mapping indicate Mn atoms in CuMn alloy either diffuse through the underlying Cu seed layer and segregate at the Cu/SiO2 interface, or migrate toward the external surface forming MnO2.
10.1016-j.jallcom.2018.01.303	6	grain; deformation; strain; strength; dislocation; cu-; tensile; size; ecap; grain size; sfe; ductility; hardening; high; stress	Effects of ultrafine grain formation via high pressure torsion (HPT) and precipitation during aging on the microstructure, mechanical and tribological properties of a Cu-Cr-Zr alloy have been investigated systematically. HPT results in the formation of ultrafine-grained (UFG) structure in the alloy with an average grain/subgrain size of 155 nm which leads to remarkable improvement in its hardness and strength along with a reduction in elongation to failure. Aging of UFG alloy brings about further strengthening due to the precipitation. UFG formation by HPT increases substantially the wear resistance of Cu-Cr-Zr alloy and reduces the friction coefficient. The highest wear resistance and the lowest friction coefficient are obtained on the sample processed by HPT and subsequent aging. The dominant wear mechanism of the alloy varies depending on the applied processes. Adhesion with smearing is the predominant wear mechanism for the initial (warm extruded) samples having coarse-grained (CG) structure. UFG samples show less adhesional effect with less smearing, and a higher tendency to the formation of cracks, abrasion and delamination seem to be dominant in those samples. Oxidative wear mechanism is also operative in both CG and UFG alloy samples. It may be concluded from this study that a combined process including UFG formation by HPT and subsequent precipitation by artificial aging provides a simple and effective processing procedure for improving the strength, hardness and wear resistance of Cu-Cr-Zr alloys without modification of the chemical composition.
10.1016-j.jallcom.2018.01.318	-1		In this present research, the nanostructured Cu alloy was successfully prepared by mechanical milling (MM) and reactive hot-pressing (RHP). The effects of milling time and sintering temperature on density, microstructure, electrical conductivity and mechanical properties were investigated. The results indicated that the nanostructured Cu had a great influence on the properties of the alloys. The crystallite size of the alloy samples exhibited a minimum value of 12 nm after milling for 6 h (by XRD and TEM). Consequently, the greatly improved mechanical properties were accompanied with a little reduced electrical conductivity due to the grain refinement. The best mechanical properties were obtained by the specimen sintered at 600 degrees C and ball-milled for 5 h . It shows a better combination of electrical conductivity (71.86% IACS) and tensile strength (649 MPa) in spite of having a density 97.46% compared with the conventional copper and Cu-Fe alloy.
10.1016-j.jallcom.2018.01.335	-1		The characteristic of layer-wise addition of selective laser melting (SLM) process leads to the anisotropy, especially reflecting in mechanical performance. In this work, the textures and thermal conductivities of an SLM-processed Cu-Ni-Si alloy were measured along the horizontal and vertical directions to establish the relationship between crystallographic texture and thermal anisotropy for the first time. Results show that the vertical plane reveals columnar grains with stronger (100) preferred orientations and the content of high-angle grain boundaries (HAGBs) is 64.6%, while for the horizontal plane, the equiaxed-like grains with (100), (101) and (111) orientations exist equally and the content of HAGBs is 52.7%. The thermal conductivity along the vertical direction (187.83 +/- 0.72 W/m K) is much higher than that along the horizontal direction (62.86 +/- 0.60 W/m K) at room temperature, indicating a strong thermal anisotropy. The thermal anisotropy can be ascribed to the grain shapes, orientations and HAGBs, which affect the grain boundary scattering extent of electron and phonon transport. The findings would be a valuable reference for tailoring thermal conductivity of SLM-processed alloys in the future.
10.1016-j.jallcom.2018.01.387	-1		A self-assembled Cu-Fe-Ni-Cr-Si immiscible composite with a bilayer structure was produced by laser induction hybrid cladding (LIHC) as a result of liquid phase separation (LPS). The microstructure exhibited by large amounts of ferromagnetic (FM) Fe3Si particles dispersed within the epsilon-Cu matrix in the upper layer, and many epsilon-Cu particles embedded within the FM Fe3Si matrix in the lower layer. The microhardness values of the Fe3Si matrix lower layer (758HV(0.2)) and epsilon-Cu matrix upper layer (248HV(0.2)) were similar to 7.3 and similar to 2.4 times higher than that of pure copper by LIHC, respectively, indicating that the immiscible composite exhibited strongly inhomogeneous characteristics consistent with a bilayer structure. Moreover, the immiscible composite showed a high saturation magnetization of 96.2 emu/g and a low coercivity of 7.24 Oe due to the formation of FM Fe3Si with micro-and nanoscaled structures.
10.1016-j.jallcom.2018.02.215	-1		We report on a study aimed at simultaneously achieving high strength, high electrical conductivity and high thermal stability in bulk nanocrystalline (NC) Cu-NbC nanocomposites. We describe an approach that involves adding NbC nanoparticles (similar to 7 nm) into a nanocrystalline Cu matrix (similar to 96 nm) via in-situ formation during sintering of high energy mechanically milled powder into a compact. Our results show that the presence of thermally stable NbC nanoparticles in the bulk NC Cu-NbC nanocomposite contributes to a high tensile strength (868 MPa) in combination with a thermally stable nanocrystalline Cu matrix, and a high electrical conductivity of similar to 56% IACS (International Annealed Copper Standard).
10.1016-j.jallcom.2018.03.169	-1		1-9 wt% of ZrB2 particles are added to Cu to produce ZrB2/Cu composites by a hot-pressed sintering process. Microstructures, mechanical and electrical properties of the prepared ZrB2/Cu composites are systematically investigated. The results indicated that the relative density and electrical conductivity of the composites decrease with increasing ZrB2 content. However, the microhardness reaches a maximum value of 100.8 HV0.2 as ZrB2 content increases to 7wt% and then decreases when ZrB2 content further increases. TEM study reveals that the hexagonal ZrB2 crystals in size of several micrometers are well embedded in Cu matrix. The interfacial zone consists of both sharp interfaces and amorphous transition layer. Grain refinement strengthening, Orowan strengthening and coefficients of thermal expansion mismatch strengthening contribute to the increment of microhardness and reduce the electrical conductivity.
10.1016-j.jallcom.2018.03.341	-1		In this study, a novel mixing method that combines wet mixing and conventional ball milling followed by spark plasma sintering (SPS) was used to fabricate carbon nanotube (CNT)-reinforced Cu-matrix composites. The samples were characterized using scanning electron microscopy, transmission electron microscopy, Raman spectroscopy, and X-ray diffraction. In the CNT/Cu composites produced, the CNTs were uniformly dispersed whilst maintaining their integrity. Consequently, a combination of high strength, ductility, and electrical conductivity was achieved by a 2.5 vol% CNT/Cu composites (ultimate tensile strength 280 MPa, elongation 41.7%, and electrical conductivity (%IACS) 91.6%). These results could potentially be used to effectively ameliorate the issue of strength-ductility and strength-conductivity trade-offs in metal-matrix composites. (C) 2018 Published by Elsevier B.V.
10.1016-j.jallcom.2018.04.117	-1		Using the Friction Stir Welding (FSW) method and incorporating a new fixture, copper and aluminum tubes were welded in a lap joint configuration, producing bimetallic copper-aluminum tubes with appropriate interdiffusion. Moreover, the effects of welding parameters such as the rotational and traverse speeds on the macro- and microstructure, the hardness profile, and the shear strength of the samples were investigated. The results showed a stronger joint is achieved by increasing the traverse speed from 30 to 60 mm/min and reducing the rotational speed from 1000 to 710 rpm. Furthermore, it was found that the curvature of the tubes and the difference in their physical properties are quite challenging when welding copper and aluminum tubes using this method.
10.1016-j.jallcom.2018.04.159	15	aging; strength; conductivity; electrical conductivity; electrical; mpa; treatment; strengthening; degrees; cu-; cold; precipitation; tensile strength; tensile; iacs	Magnesium was added into Cu-Cr alloy to overcome the traditional limitations of high-cost and large-scale manufacturing of Cu-Cr alloys and to unveil the acting mechanism of Mg on the microstructure and properties of Cu-Cr alloy. Effect of magnesium on microstructure and properties of Cu-Cr alloy has been investigated by means of hardness test, electrical conductivity measurement, transmission electron microscopy, three-dimension atom probe tomography technique and X-ray diffraction analysis. The precipitation sequence of Cu-Cr-Mg alloy was similar with that of binary Cu-Cr alloy. Additional magnesium in Cu-Cr alloy accelerated the process of precipitates nucleation, restrained the growth of the precipitates by segregating along precipitates surface during aging. This enhanced the stability of the deformation microstructure and improved the mechanical properties of the alloy. Cu-Cr-Mg alloy showed a better comprehensive properties and softening resistance performance than Cu-Cr alloy at elevated temperature. After aged at 480 degrees C, Cu-Cr-Mg alloy had a tensile strength of 540 MPa and an electrical conductivity of 79.2 %LACS for the peak aging states, and it still maintained a tensile strength of 515 MPa and an electrical conductivity of 80.8 %LACS after 4 h aging.
10.1016-j.jallcom.2018.04.224	-1		In this work, high volume fraction Y2O3 dispersion strengthened Ti-free and Ti-doped Cu samples were prepared by mechanical alloying, high temperature heat treatment and powder compact extrusion to study the role of alloying Ti element on microstructures, mechanical properties and electrical conductivity of the extruded samples. It is found that the addition of a small amount of 0.4 wt%Ti effectively suppresses the coarsening of Y2O3 particles during material fabrication, which produces smaller and more uniform oxide particles distributed in a homogeneous ultrafine grained Cu matrix. However, a heterogeneous Cu matrix microstructure, consisting of elongated micrometer-scale Cu grains and equiaxed ultrafine Cu grains, is observed in the Ti-free sample due to significant coarsening of the Y2O3 particles. The different microstructural features of the two extruded samples lead to distinctively different mechanical behaviors and electrical conductivities. The energy dispersive X-ray spectrometry elemental and high resolution transmission electron microscopy analysis suggest that the stabilizing mechanisms of the Y2O3 particles involve both the segregation of Ti atoms to the surface layers of large Y2O3 particles and dissolution of Ti atoms into small Y2O3 particles to form complex particles.
10.1016-j.jallcom.2018.04.254	-1		The newly designed bilayer Cu-Al precursor films with different Cu contents were prepared by magnetron co-sputtering. Through dealloying the precursor films, bilayer nanoporous copper (NPC) films with various morphology features were synthesized. The impacts of the features of precursor films and dealloying solution species on the final NPC film products were investigated. The direct evidence of the process of how dealloying front penetrates into the interior of precursor films was revealed. Our findings not only help understand the mechanisms occurring during the dealloying process of copper-based films, but also bring inspirations of manufacturing other novel NPC materials in the future.
10.1016-j.jallcom.2018.04.259	-1		This work presents the effects of high energy milling with different Ni and Zr ratios on the amorphization of ternary Cu-Ni-Zr alloys (initially, Cu-43Ni-7Zr, Cu-12Ni-31Zr, Cu-33Ni-7Zr, and Cu-12Ni-23Zr; and later, Cu-23Ni-15Zr and Cu-11Ni-7Zr). Microstructure was determined using X-Ray diffraction and electron microscopy. Results were compared to thermodynamic models. In the ternary alloys under study, the lattice parameter of the Cu-Ni solid solution was generally correlated to the amounts of nickel incorporated into the Cu lattice. However, longer milling times reduced that lattice parameter and facilitated Zr insertion into the solid solution. For example, after 5 h of milling time, microstructural analysis showed the formation of a solid solution with cubic structure in Cu-43Ni-7Zr. This pattern is consistent with the presence of a lattice parameter between that of Cu and Ni (alpha-phase); in contrast, the Cu-33Ni-7Zr alloy showed an alpha-phase and another similar to Zr. Results suggest that, as the amount of nickel increases, the ability to form an amorphous phase decreases. Additionally, experimental and thermodynamic data showed a solid-solution formation stage, followed by an amorphous phase formation stage that occurred as milling time and Zr content increased. (C) 2018 Published by Elsevier B.V.
10.1016-j.jallcom.2018.04.291	-1		The purpose of paper is to investigate the microstructure and properties of Cu-Cr alloys induced by high-current pulsed electron beam (HCPEB) irradiation. Microstructure of the alloying layer was studied by means of X-ray diffraction (XRD), scanning electron microscope (SEM), and transmission electron microscopy (TEM). The microhardness and friction property were also tested. The microstructure reveals that craters were formed which were fused and eliminated to form flat surface with increase of the pulse number. Additionally, the inter-diffusion of Cu and Cr elements caused component homogenization of the surface melted layer. Besides, the fine grains/particles and Cu (Cr) solid solution were formed. Those factors accounted for a significant increase in microhardness. The lowest COF and wear rate were attributed to the ultrafine Cr particles in the hard Cu matrix.
10.1016-j.jallcom.2018.04.327	-1		Cu-matrix nanocomposites reinforced with in-situ TiC were fabricated using long-term ball milling and hot pressing. Their hardness and electrical conductivity simultaneously increased with the enlargement of ball milling time after 84 h . The novel findings provide a potentially competitive strategy for developing the high-performance Cu-based composite materials. The improved electrical properties were due to the fraction increase of micro-sized pure Cu areas. The enhanced hardness resulted from the formation of composite areas that contained the nano-sized Cu and TiC. Such microstructure depended on the refinement and more homogeneous mixing of Cu and Ti nanopowders caused by enlarging ball milling time. (C) 2018 Published by Elsevier B.V.
10.1016-j.jallcom.2018.05.019	-1		Graphene nanosheets (GNS) anchored with nickel nanoparticles (Ni@GNS) are designed and used as the reinforcement to synthesize self-lubricating copper matrix composites (Ni@GNS/Cu). The tribological behavior of Ni@GNS/Cu are investigated as a function of Ni@GNS content and applied load and further compared with those of bare sintered copper and copper matrix composites enhanced with bare GNS (GNS/Cu) to elucidate the effect of Ni@GNS reinforcement, especially the interfacial bonding between graphene and copper matrix on the tribological performance of copper matrix composites. The incorporation of Ni@GNS with up to 2 wt. % significantly reduces the friction and improves wear resistance of copper matrix. Ni@GNS/Cu composites also exhibit lower frication and wear rate than GNS/Cu with the same GNS content. The improved tribological performance can be attributed to the formation of stable and compact GNS-rich tribolayer on the worn surface of Ni@GNS/Cu composites along with their higher hardness due to the improved interfacial bonding of Ni@GNS and Cu matrix.
10.1016-j.jallcom.2018.05.021	-1		Lithium containing intermetallic alloys have recently become the focus of many investigations regarding their potential application as electrode materials for lithium ion batteries. However the overwhelming increase in volume during lithiation prohibits a general use of these materials in state of the art batteries. The Cu-Li-Sb system has gained much attention in this respect, as the intermetallic compound eta-Cu2Sb showed remarkable cycling stabilities combined with a high charge capacity. To fully understand the reactions taking place upon charging/discharging of this material, a reliable phase diagram of the system is a prerequisite. Nevertheless almost no such data is available for the Cu-Li-Sb system. Especially reactions taking place at elevated temperatures become relevant regarding system malfunctions like e.g., thermal runaways of the battery cells. Therefore a substantial experimental investigation was conducted to enable the construction of three isothermal sections at 573 K, 673 K and 873 K. 83 alloy samples were thus metallurgically prepared and annealed at different temperatures. Analysis was done by powder X-ray diffraction. To validate the phase descriptions obtained from this data, electrochemical measurements were conducted. Coulometric titrations with four different Cu-Sb alloys (Cu concentrations = 80 at%, 67 at%, 50 at%, 33 at%) showed a good agreement with the phase fields expected from the powder X-ray diffraction data. 48 of the 83 samples were in addition analyzed by differential thermal analysis, which enabled the construction of two vertical sections (isopleths). These followed the lines connecting the binary alloy compositions Cu66Sb34 and Cu50Sb50 with Li. In addition a liquidus projection showing in- and monovariant reactions, together with liquidus isopleths could be outlined. Finally a reaction scheme including all invariant reactions found within the system was developed.
10.1016-j.jallcom.2018.05.135	16	wear; composite; composites; powders; milling; particles; powder; wt; sliding; friction; hardness; matrix; mechanical; surface; properties	Homogenized Cu-4Ti (wt%) and Cu-4Ti-1.4B (wt%) powders were cold pressed and then sintered by pulsed, millisecond Nd:YAG laser system. Phases present in laser sintered samples were characterized by X-ray diffraction (XRD), while quantitative chemical analysis of the sintered samples was conducted using inductively coupled plasma-atomic emission spectrometry (ICP-AES). The microstructure of powders and laser sintered foils was examined with scanning electron microscope with an energy dispersive X-ray spectroscope (EDS). Optical microscopy was used also for microstructural characterization of the foils. The tensile test was carried out using a universal testing machine with a crosshead speed of 0.5 mm/min at room temperature. Foils with dimensions 20 x 6 x 0.4 mm were used for tensile testing. In the obtained Cu-Ti foils, after aging at 550 degrees C for 4 h, rapidly solidified structure and metastable Cu4Ti precipitates affected high degree of copper matrix strengthening (peak aged). In Cu-Ti-TiB2 foils, after aging at 550 degrees C for 3 h, rapidly solidified structure, as well as the presence of TiB2 particles and metastable Cu4Ti precipitates, also affected high degree of copper matrix strengthening which, thanks to the ceramic particles, is retained at longer times (6 h). Fractured surfaces were observed with an optical microscope. It was determined that the best structural and mechanical properties of laser-sintered foils were reached using the following parameters: laser frequency 4 Hz, laser pulse duration 9 ms, pulse energy similar to 20 J, number of scans 2.
10.1016-j.jallcom.2018.05.297	-1		The microstructural features required to optimize both the strength and ductility of copper are investigated by examining the as-cast pure Cu and Cu-(1.0e3.0)Fe-0.5Co and Cu-1.5Fe-0.1Sn (wt%) alloys. Uniaxial tensile tests show that (Fe, Co)- or (Fe, Sn)-doping improves both the strength and ductility of pure copper. The microstructure evolution with Fe, Co, or Sn doping is characterized by using optical and scanning and transmission electron microscopies. The effects of Fe, Co, and Sn doping on the microstructure clearly show that (i) iron-rich nanoparticles are dispersed inside the grains. The spherical nanoparticles grow in size with increasing Fe content, and when the Fe content exceeds 2.0 wt%, the particles transition into a petal-like morphology. (ii) The microstructure of the alloys (grain size and morphology) is notably influenced by the Fe and Co contents, and the grain size is reduced from an average of 603 mu m in pure Cu to an average of 26 mm in the Cu-3.0Fe-0.5Co alloy. (iii) The addition of 1.5wt% Fe and 0.1wt% Sn dramatically reduces the grain size to an average of 42 mu m, and this reduction is correlated with the appearance of smaller spherical iron-rich nanoparticles. The evolution mechanisms of the iron-rich nanoparticles and grain structure under the alloying effect are discussed.
10.1016-j.jallcom.2018.06.043	6	grain; deformation; strain; strength; dislocation; cu-; tensile; size; ecap; grain size; sfe; ductility; hardening; high; stress	This work reveals the grain refinement process of low-stacking fault energy Cu-4wt%Ti alloy during surface mechanical attrition treatment (SMAT). Without phase transformations, the grain refinement process in Cu-4wt%Ti alloy with a low stacking fault energy involves formation of planar dislocation arrays and twins in the small strain and low strain rate deformed region adjacent to the coarse grain matrix, twin-twin intersections leading to grain subdivision. The formation of lamellae, polygonal grains, and rotation recrystallization were induced by the large strain and high strain rate deformation near the treated surface. We also observed one distinct layer at the treated surface with the thickness about 15 mm, which is filled with equiaxed nanograins. The hardness of the treated surface was increased by 40% and attributed to the grain refinement according to the grain boundary strengthening mechanism.
10.1016-j.jallcom.2018.06.158	-1		The dynamic interaction between precipitates and dislocations is a fundamental scientific principle for the precipitation hardening, which is hardly captured by post characterizations. In-situ tension experiments in transmission electron microscope (TEM) have been performed on the precipitation strengthened Cu-0.55 wt% Cr-0.05 wt% Zr alloy. The dynamic interaction between dislocations and Cr precipitates was recorded. The results showed that dislocations were pinned by the semi-coherent Cr precipitates and exhibited a typical intermittent gliding. The shearing mechanism was the prevalent one for the dislocations disengaging the Cr precipitates. The critical stress for shearing the Cr precipitates increased as the dislocations subsequently cut through the Cr precipitates. The in-situ tension technique in TEM could present a direct evidence of the deformation in the precipitation hardening alloys.
10.1016-j.jallcom.2018.06.250	4	transformation; martensite; martensitic; phase; shape; beta; memory; shape memory; temperature; temperatures; martensitic transformation; gamma; transformation temperatures; effect; thermal	The influence of processing, heat-treatment and aging of Cu-(8-9) wt% Al-(7-10) wt% Mn alloy on the kinetics and temperatures of martensitic transformation was investigated by calorimetric measurements. Cu-Al-Mn alloy was prepared by continuous casting, melt-spinner and by melting in the electric arc furnace. Alloys were further heat-treated at 900 degrees C for 30 min and quenched in water, as well as aged at 300 degrees C for 1 h . Differential Scanning Calorimetry (DSC) was performed at 3 heating/cooling cycles from -50 to 250 degrees C. Non-isothermal measurements were determined at five different heating/cooling rates: 5, 10, 15, 20 and 25 degrees C/min. Activation energy was obtained according to Ozawa and Kissinger kinetic models. Microstructure analysis of investigated systems was performed by scanning electron microscopy (SEM). Results indicate the most intensive formation of martensitic structure in the as-cast state during continuous casting, where the partially formation of needle-like and V-shape martensite was observed. After solution treatment and quenching as well as aging, completely martensitic phase occurred in continuously cast alloy. XRD analysis detected Cu2AlMn, Cu3Al and Al4Cu9 phases in quenched specimens of continuously cast Cu-Al-Mn alloy and ribbon. The highest impact of the solution treatment and aging on the shifting of the martensitic temperatures was observed for Cu-Al-Mn ribbons, while in continuously cast Cu-Al-Mn alloy heat treatment and aging induced formation of different martensitic crystal structures. Kinetic investigations showed increasing start martensitic temperatures, M-s, and wider temperature interval of martensitic transformation with higher cooling rate. The highest values of activation energy of martensitic transformation was obtained for the continuously cast Cu-AlMn alloy.
10.1016-j.jallcom.2018.06.327	-1		In situ TiC particles reinforced Cu matrix composites have been prepared by melt reaction method in this work. It is found that, during the preparation, not all the added graphite can react with soluble Ti to form TiC due to its poor wetting and very limited solubility in Cu melt, which will lead to residue of both graphite and Ti in the composites. Because the residual Ti will dissolve in the Cu matrix, it will seriously degrade the conductivity of the composites. In order to improve the electrical conductivity of Cu-Ti-C composites prepared by the melt reaction method, boron can be added to the composites to consume the residual Ti by the formation of TiB2 . It is confirmed that the addition of B will make the distribution of the reinforced particles more homogeneous, most of all, can remarkably improve both the hardness and electrical conductivity of the Cu-Ti-C composites.
10.1016-j.jallcom.2018.06.365	-1		A powder metallurgical approach was developed to fabricate Cu-(30-60 wt%) Mg alloy foams with close pore structure by taking advantage of the gas release reaction between Mg and CaCO3. The key to ensure the successful foaming is the sintering treatment, which leads to Cu and Mg forming intermetallic compounds with low melting temperatures (<600 degrees C). The compression experiment results show that the intermetallic compounds in the cell wall make the foam brittle; however, a certain amount of Mg in the cell wall makes the Cu-Mg alloy foam possess a higher compressive strength .
10.1016-j.jallcom.2018.07.020	-1		Towards a resolution of the longstanding controversy regarding the existence of Cu-Li intermetallic compounds, we extensively investigate the phase stability of Cu-Li intermetallics with various possible stoichiometries at zero temperature and pressure using a global structure searching method. It is found that Cu-Li intermetallics can exist stably at atmospheric pressure, and three stable phases (Fmmm Cu1Li2, Fd (3) over barm Cu2Li1, and P (1) over bar Cu7Li1) are identified. Electronic structure analysis reveals that although they are metallic, covalent Cu-Cu and ionic Cu-Li bonds are found in the three structures. Moreover, the 3d states of copper atoms are mostly responsible for bond formations in the stable phases predicted. For all the predicted Cu-Li intermetallics, the effect of Cu concentration on structure, mechanical and thermodynamic properties are calculated systematically. It is found that the copper atoms in Cu-Li intermetallics trend to form covalent bonds, so more covalent bonds are formed as Cu content increases, leading to the increases in the elastic moduli, Vicker hardness and Debye temperature with Cu content on the whole. The Poisson's ratios of Cu-Li intermetallics vary in the range of 0.25 and 0.35, and most of Cu-Li intermetallics exhibit an excellent ductile property. The elastic anisotropy calculations suggest that all the Cu-Li intermetallics show anisotropic elasticity more or less, and the percentage anisotropy in compressibility is smaller than that in shear for each of the predicted Cu-Li compounds.
10.1016-j.jallcom.2018.07.155	-1		Bulk ultrafine grained metal matrix composites (MMC) have attracted much attention of many researchers due to their potential in terms of excellent mechanical properties for engineering applications, such as high strength, which can be two or more times of that of their coarse grained counterpart. Bulk ultrafine grained Cu-3wt%C MMC samples were produced by Ball-Milling (BM) followed by Spark Plasma Sintering (SPS), at a temperature of 900 degrees C. The Cu-C MMC was compacted progressively by repeating the BM + SPS procedure without changing the weight ratio between Cu and graphite. The room temperature creep behavior, and the strain rate sensitivity (SRS) were inspected by using nanoindentation measurements. Strain rate ranged 0.0025-to-0.5 s(-1), and the contact dwelling times ranged 5-to-300 s. A secondary steady-state regime was reached starting from a dwelling time of 120 s irrespective of the strain rate and Cu-C compaction level. A negative trend of the SRS exponent with Cu-C compaction was obtained, with creep stress exponent as high as 28. These results were discussed according to the microstructure features that differentiated the Cu-3wt% C MMC obtained by the progressive BM thorn SPS compaction levels.
10.1016-j.jallcom.2018.07.258	6	grain; deformation; strain; strength; dislocation; cu-; tensile; size; ecap; grain size; sfe; ductility; hardening; high; stress	The anneal hardening behavior of Cu-7at%Pd alloy after deformation by cold rolling was investigated by means of hardness, microhardness, electrical conductivity, light optical microscopy (LOM), scanning electron microscopy (SEM), and energy dispersive spectroscopy (EDS). In this regard, the cast Cu-7at%Pd alloy after quenching was deformed with 20% and 40% reductions and isochronally annealed between 100 degrees C and 700 degrees C. After annealing up to 400 degrees C, the deformed samples exhibited atypical anneal hardening behavior in combination with an increase in electrical conductivity. In addition, the recrystallization was substantially retarded by the applied thermo-mechanical treatment which included solution annealing, quenching, cold rolling, and annealing. The microstructural evolution during a low-temperature annealing proved a strong pinning of grain boundaries by solute palladium atoms, indicating that grain boundaries have an important role during the anneal hardening.
10.1016-j.jallcom.2018.07.318	-1		An enhancement on thermoelectric performance of Cu2GeSe3 via simultaneously Ag-alloying on Cu sites and Ga-doping on Ge sites is achieved. The relatively high solubility (similar to 10%) of Ag on Cu sites allows for the strong point defect scattering for phonons, which causes remarkable reduction in lattice thermal conductivity. Ag-rich precipitates emerge when the amount of Ag is higher than the solubility on Cu site, which however do not have significant effect on the lattice thermal conductivity since it is already very close to the lower limit of kinetic theory. Ga-doping, an effective way to tune the hole concentration, leads to optimization of power factor in the whole temperature range. The maximal zT obtained in Cu1.9Ag0.1Ge0.997Ga0.003Se3 is 1.03@786 K, about 58% higher than that in previous report. In addition, the average zT in the temperature range from 320 K to 786 K is 0.58, implying great potential for fabrication of thermoelectric devices.
10.1016-j.jallcom.2018.08.012	-1		The effect of cooling rates on the solidified microstructure of Cu-50Cr (wt. %) produced by laser surface melting (LSM) was studied. Layered structure transformed into a dispersed structure when the cooling rate increased from similar to 10(5) K/s to similar to 10(6) K/s. The average diameter of the Cr-rich spheroids in the homogenous layer was reduced to less than 1 mu m, and the migration velocity by Marangoni motion was similar to 10(3) times higher than the velocity by Stokes sedimentation, suggesting that the movements of alpha-Cr droplets containing supersaturated Cu phase during liquid phase separation (LPS) were dominated by Marangoni motion. Although the collisions and coagulations between Cr droplets couldn't be eliminated, the growth was suppressed by high cooling rate. The melt layer presented improved homogenous microhardness and the well-dispersed melt layer exhibited higher withstanding voltage than that of the untreated.
10.1016-j.jallcom.2018.08.033	-1		Brass (Cu-Zn) is one of the typical Hume-Rothery alloys, which is extensively used in material science and industry. Earlier studies revealed that the structures of Cu-Zn alloys correlate with the average number of valence electrons or the electron-per-atom (e/a) ratio, but structural evolution rule still remains unclear. In this work, the Cu-Zn nanoalloy clusters (elementary cells of bulk brass) are studied to reveal the evolutional rule of their structures with sizes. Systematic unbiased global search is performed for structural prediction of CuxZny nanoalloys in a size range (x + y = 3-10) by using genetic algorithm with density functional theory. The global minimum and low-lying isomers of the series of nanoalloy clusters are obtained, and the structural phase diagrams are plotted depending on the relative energy. The results show that geometric structures of Cu-Zn nanoalloys are also determined by the total number of valence electrons (n*), just as in bulk brass. Cu-Zn nanoalloys with same n* have similar geometric motifs. When n* = 6, the clusters adopt planar motif, which have sigma-aromaticity following the (4n+2) rule. When n* = 8, 18 and 20, the clusters keep spherical motifs, which satisfy the magic numbers of Jellium model and could be viewed as stable superatoms. In most of cases for n* = 10, 12 and 14, the clusters adopt prolate motifs, which have similar electronic structures to N-2, O-2, and F-2 molecules, respectively, based on the super valence bond model. Moreover, in some cases for n* = 10 and 12, the clusters can be seen as an 8e-superatom combined with one (8e+2e) or two (8e+2e+2e) separate Zn atoms. (C) 2018 Published by Elsevier B.V.
10.1016-j.jallcom.2018.08.107	-1		Graphite flake/Cu composites with Zr element introduced into the matrix were successfully fabricated by vacuum hot pressing. The influence of Zr addition on the phase composition, microstructure and properties were investigated. The results indicate that the bending strength in X-Y plane gradually rises with the Zr content increasing from 0 to 2.0 wt%, nearly doubled from 50 MPa to 95 MPa. The thermal conductivity in X-Y plane initially increases and then decreases, yielding a maximum of 640 W m(-1) K-1 at 1.0 wt% Zr. This improvement is ascribed to the formation of carbide interfacial layer at the graphite flake/Cu interface. Due to the simple preparation process and excellent thermal conductivity, the graphite flake/Cu composites with moderate Zr addition can be a highly promising candidate for thermal management materials.
10.1016-j.jallcom.2018.08.116	-1		CNTs/Cu-Ti composites were fabricated successfully by spray pyrolysis, low energy ball milling and subsequent hot pressing (HP). Microstructure and mechanical properties of the composites were characterized by SEM, EDS, HRTEM, XRD, hardness and tensile tests. The results reveal that in situ generated nano-TiC particles, as a transition phase from CNTs to Cu-Ti matrix, which played a rivet role in enhancing the interfacial bonding between the CNTs and Cu-Ti matrix is formed in the composites. Consequently, mechanical properties of the CNTs/Cu-Ti composites are enhanced compared with alloy matrix, and an optimal balance between elevated ultimate tensile strength and impressively larger plastic deformation is achieved by adding 0.4 wt% CNTs in the composites. (ultimate tensile strength (UTS) 352 MPa, elongation 28.2%, the UTS is 39% higher than that of the Cu-Ti alloy, and the ductility increased significantly by 62%.) Finally, strengthening and toughening mechanisms are discussed. This study provides new insights into the interface structure and strength-ductility in metal-matrix composites.
10.1016-j.jallcom.2018.08.130	11	glass; bulk; metallic; bulk metallic; gfa; bmg; glassy; metallic glass; ability; bulk metallic glass; amorphous; addition; crystallization; mm; glass-forming	This work highlights the preparation, microstructure, wear resistance and mechanical property of Cu-Zr -Al-Y bulk metallic glass (BMG) and its composites (BMGC) containing high contents of Al (7, 10, 13, 16 at%). The results show that the best glass forming ability and thermal stability are achieved by 10 at% addition of Al. For BMGs, due to the generation of phase separation, the best ductility is obtained in 7Al alloy with the plastic strain of 4.7%. The compressive strengths of high Al contents alloys (10, 13 and 16 at%) were significantly improved compared with that of 7Al alloy. Simultaneously, wear resistance and hardness are also slightly improved. For 7Al BMGCs, precipitation of 13 vol% B2 phase has better wear resistance compared with the BMG, When B2 phase increases to 35 vol%, the martensitic transformation produces work hardening, which improves mechanical properties (sigma(f) = 1819 MPa, epsilon(p) = 4.3%). The present work provides important insights for creating a novel functional structure material with low cost, high wear resistance, light weight and high strength .
10.1016-j.jallcom.2018.08.247	6	grain; deformation; strain; strength; dislocation; cu-; tensile; size; ecap; grain size; sfe; ductility; hardening; high; stress	The influence of alloy concentration with different stacking fault energy (SFE) on tensile properties of Cu and Cu-Al alloys processed by high pressure torsion (HPT) at room temperature (RT) and liquid nitrogen temperature (LNT) was investigated. With decreasing SFE, the twinning capability, the dislocation density and grain refinement were enhanced at LNT, however, tensile strength and uniform elongation were not simultaneously improved. The enhanced tensile properties are explained in terms of the twinning capability, the grain size and the dislocation density independent of the short range order (SRO).
10.1016-j.jallcom.2018.08.274	-1		Copper micro-flakes were encapsulated with in situ catalytically grown graphene and then assembled into graphene/Cu (Gr/Cu) laminated composite under pressure at high temperature. The thermal conductivity (TC) and coefficient of thermal expansion (CTE) of the composites were investigated systematically. Although in situ catalytic growth graphene can avoid structural damage in a usual mechanical alloying process and is beneficial for improving interfacial bonding, the Gr/Cu laminated composites show decreased TC in both directions compared to the pure Cu matrix prepared by the same process. The composites exhibit anisotropic thermal properties owing to their laminated architecture and two-dimensional character of graphene. Given a volume fraction of graphene, the cross-plane TC of the Gr/Cu composite is lower than the in-plane TC because of more multilayer-graphene/copper interfaces and low cross-plane TC of graphene. Although the fraction of graphene is only 0.75 vol%, the Gr/Cu composite has a significantly lower cross-plane CTE than the pure Cu matrix in a wide temperature range.
10.1016-j.jallcom.2018.09.040	-1		A two-step cryorolling and aging process was developed to fabricate high strength and high electrical conductivity CuCrZr alloys. The microstructural evolution, mechanical and electrical properties of Cu-1Cr-0.1Zr (wt%) alloys subjected to the two-step cryorolling and aging process were investigated. The results showed that this two-step process reduced the width of the deformation bands from 113 nm to 80 nm. The introduction of precipitates in the matrix during intermediate aging was responsible for the narrowing of the deformation bands. Even though the cryorolled sample underwent detwinning, its ultimate tensile strength improved by similar to 35 MPa. Ordered face-centered cubic (fcc) Cr precipitates similar to 5 nm in size were observed in the Cu matrix, and these precipitates had a pinning effect on the motion of boundaries. A desired balance between the ultimate tensile strength (648 MPa) and electrical conductivity (79.80% IACS) was achieved by the coexistence of refined deformation bands, nanoscale deformation twins and nanoprecipitates.
10.1016-j.jallcom.2018.09.167	-1		A kind of nanofiber-enclosed nanoporous structure is fabricated from a Cu-Ti glassy film by dealloying in an alkaline solution. The Cu-Ti glassy films are prepared by a combination of electron beam evaporation of pure Ti and resistance thermal evaporation of pure Cu. The dealloyed films mainly consist of titanium dioxide and a Cu4Ti3 intermetallic compound. Transient photocurrent response tests show that the obtained nanostructured films have considerable ultraviolet light photoresponse activity and exhibit both the typical n-type and p-type currents under UV-irradiation (wavelength lambda = 365 nm). The mechanism is discussed in relation to the special nanostructure of the dealloyed films. The results demonstrate that the dealloyed Cu-Ti glasses have potential for applications in photocurrent detectors.
10.1016-j.jallcom.2018.09.179	-1		We investigated the microstructure and mechanical properties of deformed Cu-26 wt%Ag alloy and Cu26 wt%Ag-0.1 wt%Fe alloy superimposed by thermomechanical process. The addition of 0.1 wt% Fe into Cu-26 wt% alloy refined the eutectic lamella spacing and the spacing between Ag precipitates. Magnetization measurements of containing-Fe composites indicated that the transformation from gamma-Fe to alpha-Fe was induced during cold deformation and the volume fraction of a-Fe increased as the strain increased. Intermediate heat treatments caused the precipitation of gamma-Fe precipitates out of Cu matrix. The solid solution as well as addition for the Cu-Ag alloy with high Ag content was beneficial to the strength rather than the electrical conductivity. Although intermediate heat treatments (IHTs) improved electrical conductivity effectively, the strength of IHT samples was lower than that of solid-solution-treated samples.
10.1016-j.jallcom.2018.09.206	1	shape; memory; shape memory; damping; martensite; martensitic; damping capacity; transformation; capacity; strain; superelasticity; temperature; cu-al-mn; shape memory effect; effect	Oligocrystalline Cu-Al-Mn shape memory foams with a pore size of 0.8-1.1 mm and a porosity of similar to 70% were prepared by the silica-gel beads infiltration method, subjected to long-time and cyclic heat treatments. The effect of grain size and oligocrystallinity (ratio of grain size to strut node diameter) on the damping and pseudoelastic properties of the foams were investigated. The peak damping increases with oligocrystallinity because a higher oligocrystallinity favors the martensite accommodation and mobility of phase interfaces during martensitic transformation. The low-amplitude martensite damping first increases and then decreases with increasing oligocrystallinity, because the martensite plates grow wider in larger grains with lower grain constraints, leading to fewer interfaces and lower damping. The high-amplitude martensite damping increases linearly with increasing oligocrystallinity, despite the wider martensite plates and reduced interfaces, indicating that the mobility of martensite plates for higher displacements is more favored by reduced grain constraints. The maximum recovery strain increases linearly with oligocrystallinity and a high value of 5.53% was achieved after cyclic heat treatment for 16 times, corresponding to an oligocrystallinity of 7.88. The high recovery strain results from the reduced triple junctions and grain boundary area due to grain enlargement that lowers the grain constraints.
10.1016-j.jallcom.2018.09.296	15	aging; strength; conductivity; electrical conductivity; electrical; mpa; treatment; strengthening; degrees; cu-; cold; precipitation; tensile strength; tensile; iacs	A process of heating-cooling combined mold horizontal continuous casting -> cold rolling -> solid-solution treatment was used to produce Cu-1.7 wt% Be alloy sheet, and the precipitation behavior, microstructure and properties of the Cu-1.7 wt% Be alloy sheet during aging were investigated. The results showed that the phase transformation sequence of the alloy during aging at 325 degrees C was GP zone -> gamma ''-> gamma' -> gamma equilibrium phase. The reasonable aging parameters were aging temperature of 325 degrees C and aging time of 3 h, and the hardness, tensile strength and yield strength of the aged alloy reached the peak values of 375 HV, 1042 MPa and 778 MPa, which were 172%, 116%, and 255% higher than those of the solid-solution alloy, respectively, and the electrical conductivity was 22.4% IACS. The formation of a large number of dispersed nano-sized gamma' phase was mainly responsible for the high strength of the alloy. A dynamic model of aging precipitation was established and the yield strength of the peak-aged alloy was calculated by the strengthening model. The deviation of the calculated value (797 MPa) and the measured value (778 MPa) was 2.4%, and the strengthening mechanism of the peak-aged alloy was determined as the Orowan bypass mechanism.
10.1016-j.jallcom.2018.10.023	2	corrosion; surface; film; electrochemical; films; spectroscopy; layer; current; solution; potential; resistance; composition; x-ray; ions; showed	Electrodeposition of Cu-based alloys has been researched for a variety of applications due to Cu-based alloys having superior properties compared to pure Cu, including higher chemical resistance, mechanical hardness, and electrocatalytic activity. Cu-Ag is the most electrically conductive among Cu-based alloys, and it has higher mechanical hardness and oxidation resistance compared to pure Cu. Cu-Ag co-deposition in cyanide-based electrolytes has been previously reported; however, the toxicity of cyanide limited its use. In this study, we introduce an ammonium hydroxide-based electrolyte for Cu-Ag electrodeposition and the properties of Cu-Ag films deposited in this electrolyte. Electrochemical measurements were performed to determine the potential range for co-electrodeposition of Cu and Ag, and the effect of nitrate reduction on the film deposition was examined. The effects of deposition potential and concentration of Ag ions in the electrolytes on the electrical resistivity and Ag contents of the films were investigated. The modulation of Ag ion concentration was found to be a more effective way to control Ag contents in the deposited films. Co-deposition of 4 at% Ag with Cu in the ammonium-hydroxide electrolyte markedly improved mechanical hardness and oxidation resistance compared to a pure Cu film without severe deterioration of electrical conductivity.
10.1016-j.jallcom.2018.10.139	-1		Graphene reinforced Cu matrix composite was fabricated by consolidating mechanically mixed powder blend to 98% theoretical density by High Pressure Torsion (HPT). Microstructural characterization by scanning electron microscopy (SEM) elicits even distribution of the reinforcement phase into the matrix. X-ray diffraction (XRD) and transmission electron microscopy (TEM) confirms nanocrystalline microstructure and strong interfacial bonding between Cu and graphene. Addition of 10 wt% graphene yields maximum hardness (similar to 2.67 GPa) and Young's modulus (similar to 102.03 GPa). The increment in strength was attributed to the microstructural refinement and dislocation pinning at the strong matrix-reinforcement interface. The electrical conductivity of the Cu- 10 wt% graphene composite was found to be similar to 87% IACS. Results indicated that HPT consolidation is an efficient mean for synthesizing Cu-graphene composite with improved strength (similar to 2 times higher hardness than pure Cu processed under similar condition) with negotiable conductivity. (C) 2018 Published by Elsevier B.V.
10.1016-j.jallcom.2018.10.176	-1		The microstructure and the shape memory effect of Cu-13.0Al-4.0Ni high temperature shape memory alloys doped with different contents of boron (0.25 wt%, 0.5 wt%, 1.0 wt%, and 2.0 wt%) were studied in this paper. According to the obtained results, it was observed that the microstructure and the shape memory effect were sensitive to the addition of boron, and the addition of boron not only enhanced the mechanical properties of the Cu-13.0Al-4.0Ni alloy, but also greatly improved the shape memory effect of the alloy. The fracture of martensite changed from intergranular fracture to transgranular cleavage fracture. In addition, it was found that the highest shape memory effect was achieved by the addition of 0.25 wt% boron.
10.1016-j.jallcom.2018.10.275	-1		Bulk nanocrystalline alloys usually possess enhanced properties than their coarse-grained counterparts. Here, first-principles calculations and aberration-corrected transmission electron microscope (TEM) were employed to investigate the atomic-scale deformation mechanism of Cu-based alloys. The effect of alloying element concentration and temperature-induced solute distribution on the unstable stacking fault energy (gamma(usf)), stable stacking fault energy (gamma(isf)) and unstable twin fault energy (gamma(utf)) were calculated using a Fermi-Dirac distribution of solutes for 42 binary Cu-X alloys. At medium temperature (>200 K) or low solute concentrations (<15 at%), the stacking fault energies calculated from the Fermi-Dirac model accord well with the available experimental and theoretical results. The deformation mechanism was then evaluated by alpha = gamma(isf)/gamma(usf) and beta = gamma(utf)/gamma(usf), smaller alpha (beta) favors an easier formability of extended dislocations (twins). Most subgroup VI-VIII metals in the periodic table can slightly increase the gamma(usf), gamma(isf) and gamma(utf) of Cu, and have almost no influence on a and B. While main group and subgroup II-V elements can decrease gamma(usf), gamma(isf) and gamma(urf) as well as the values of alpha and beta. For alloying elements of Pd, Ag, Pt and Au, the values of alpha and beta increase, suggesting a tendency of deformation mechanism from extended dislocations to full dislocations. Furthermore, high-resolution TEM (HRTEM) images of four representative nanocrystalline alloys (pure Cu, Cu-Fe, Cu-Ag and Cu-Zn) corroborates the prodiction with alpha and beta as well as the empirical twinnability. The alpha and beta remain almost the same as that of pure Cu when alloyed with Fe while they decrease with Zn, and the extended dislocations and twins were commonly observed for Cu, Cu-Fe and Cu-Zn. The alpha and beta increased with Ag addition although the gamma(isf) decreased, and the extended dislocations were barely observed for Cu-Ag sample. The theoretical and microstructural correlation provides insights into the deformation mechanism of Cu-based alloys.
10.1016-j.jallcom.2018.10.332	-1		The equilibrium Cu-Pd phase diagram has been experimentally reinvestigated in the 300-680 degrees C temperature region by powder XRD involving a high-temperature technique. To reduce the annealing time needed for the system to attain the equilibrium state, nanosized specimens with a characteristic crystallite size of 5-15 nm were used initially. All previously reported phases, i.e., a disordered face-centered cubic solid solution Cu1-xPdx (A1), a one-dimensional long-period superlattice structure Cu21Pd7 (1D-LPS), intermetallic compounds Cu3Pd (L1(2)) and CuPd (B2), except a two-dimensional long-period superlattice structure (2D-LPS), could be confirmed. Homogeneity ranges of all solid phases existing in the Cu-Pd system were determined at distinct temperatures. The largest deviation of the solubility limits was observed for the Pd-rich boundary of the Cu3Pd region (25-30 at% Pd) and the Cu-rich boundary of the Cu1-xPdx region in the compositional range >55 at% Pd. Based on the present experimental results, the constitutional Cu-Pd diagram was modified.
10.1016-j.jallcom.2018.10.340	-1		Copper alloys show a structural variability leading to a range of diverse electronic, transport, and mechanical properties. Here, we investigate the influence of the type and amount of alloying on the electronic transport properties across copper alloys. Specifically, we investigate the electronic transmission along copper in its fcc crystal structure. The characteristic change when adding impurities, such as nickel, aluminum, and silicon in the structure and transport properties is assessed through density functional theory calculations together with the non-equilibrium Greens functions approach . The results are analyzed with respect to the structural characteristics, the electronic and transport properties in these alloys for different concentrations of the impurities. A clear trend in the electronic transmission, thus the conductance, along these materials was found with the addition of certain impurities and their clusters. Coherent with experimental observations, we conclude that the higher the concentration of the impurities, the lower the electronic transmission along the alloys as compared to a pure copper crystal. Furthermore, we show that the bonding environment in the impurity clusters can be associated to additional valence states and significantly influences the conductance. In the end, we discuss the relevance of our results for practical applications.
10.1016-j.jallcom.2018.10.396	-1		Limited glass-forming ability (GFA) and room-temperature brittleness are currently critical challenges for the field of bulk metallic glasses (BMGs). Simultaneously enhancing GFA and plasticity is a central yet important research theme in this area. In contrast to the traditional wisdom, herein we report that addition of the elements with positive heat of mixing (PHM) into Cu-Zr-Al BMGs not only facilitated glass formation but also enhanced plasticity. It was found that the elements with a smaller PHM value have a larger optimal dose and are more effective in enhancing GFA due to stabilization of the liquid phase with an enhanced packing density and destabilization of the crystalline phase by slowing down the atomic rearrangement. Moreover, addition of the elements with a medium PHM value is beneficial for plastic deformation because of the enhanced structural heterogeneity. The established composition-GFAproperties relationship is useful for designing novel BMGs with both enhanced GFA and plasticity via alloying the PHM elements.
10.1016-j.jallcom.2018.11.096	-1		With the rapid development of ultrahigh voltage engineering (>500 kV), it has been increasingly difficult to satisfy the high requirements of traditional electrical contact materials for ultrahigh voltage circuit breakers. The copper/graphene (Cu/G) composite coatings on a pure copper substrate are successfully fabricated using a facile method of cathodic co-electrodeposition. The morphology, structure, coating composition and porosity of the Cu/G composite coatings were studied. The Vickers hardness of the Cu/G composite coating shows an increase of approximately 25% compared to a pure copper coating. The addition of graphene in the composite coating with a low friction factor of approximately 0.2 improves the wear resistance. The thermal conductivity of the Cu/G composite coating prepared in a plating solution of 10 g L-1 graphene content reaches 285.2 W m(-1) k(-1) at room temperature, which is an increase of 61.9% compared to a pure copper coating. The average chopping current (3.6 A) of the Cu/G composite coating is superior to that of the Cu20W80 alloy, indicating an improved arc ablation resistance. The Cu/G composite coating provides new possibilities to replace the traditional electrical contact materials of ultrahigh voltage circuit breakers.
10.1016-j.jallcom.2018.11.215	-1		The hollow Fe-p-reinforced Cu-matrix homogeneous immiscible alloys were successfully produced by the combination of Kirkendall effect and laser powder deposition. The microstructure and corrosion resistance depended not only on chemical composition, but also on cooling rate. When Fe content decreased from 30% to 12% and cooling rate decreased from similar to 2 x 10(4) to similar to 1 x 10(4) K/s, the demixing was eliminated, the mixed Fe-p (alpha-Fe/gamma-Fe) were uniformly embedded within epsilon-Cu matrix and the single-void Fe-p transformed into the multi-voids Fe-p. The multi-voids immiscible alloy exhibited higher corrosion resistance than the single-void immiscible alloy and Brass after immersing for 5 days.
10.1016-j.jallcom.2018.11.287	-1		The microstructure, residual stress, and mechanical properties of a Cu-0.05wt%Al2O3 dispersion strengthened alloy in different treatment states were investigated. The alloy was cold forged with a reduction of 60%, followed by either normal annealing or creep annealing at 600 degrees C for 6 h . Compared with the cold forged alloy, the micro-yield strength and the residual stress of the creep annealed alloy were reduced by 8.2% and 80.3%, respectively. The significant decrease in residual stress after creep annealing could result from the elimination of voids and defects and the reduction of dislocation density in the sub-grains during heat treatment. The high micro-yield strength of the creep annealed alloy can be attributed to the well dispersed nano Al2O3 particles effectively pinning the sub-grain boundaries at the elevated temperature.
10.1016-j.jallcom.2018.12.017	1	shape; memory; shape memory; damping; martensite; martensitic; damping capacity; transformation; capacity; strain; superelasticity; temperature; cu-al-mn; shape memory effect; effect	Columnar-grained Cu-Al-Mn shape memory alloy (SMA) can experience high superelastic strain exceeding 7% and exhibits a nearly 100% superelastic recovery ratio due to its straight grain boundaries and strong texture along the solidification direction, which allows it to reach the strain level of a single crystalline Cu-based or Ni-Ti SMAs and possesses a potential for damping applications. In this paper, the damping capacity of Cu-Al-Mn SMA in various deformation conditions during a strain-controlled superelastic cyclic tensile process was studied. The anisotropy characteristics and the cyclic effect of damping capacity were analysed. The damping capacity of columnar-grained Cu-Al-Mn SMA increases as the loading strain increases in superelastic tensile processes, and a large damping capacity anisotropy occurs. At low loading strain (<6%), T-45 degrees sample (45 degrees is the angle between the loading direction and the axis of columnar grains) has the largest energy dissipation per unit recovery strain, Delta W-1%, due to its high-stress level. At high loading strain (>6%), T-0 degrees and T-15 degrees samples can achieve a good damping capacity because of high superelasticity and plasticity. In addition, the damping capacity of columnar-grained Cu-Al-Mn SMA along the solidification direction has a significant cyclic effect. At the same loading strain (4%-10%), Delta W-1%, and loss angle, Delta W/2 pi W first decrease to the minimum, then increase to the maximum and, finally, decreases as the number of cycles increases. The minima and maxima of Delta W-1% and Delta W/2 pi W at different strain amplitudes correspond to the similar residual strain ratio, epsilon(r)/epsilon(t). The change curves of damping capacity related to epsilon(r)/epsilon(t) can be divided into three stages: the stable damping capacity stage with low residual strain; the rapidly increasing damping capacity stage; the sharp cumulative stage of residual martensite with limited values of strain damping capacity.
10.1016-j.jallcom.2018.12.022	8	hot; deformation; strain; strain rate; dynamic; hot deformation; recrystallization; dynamic recrystallization; flow; rate; flow stress; compression; constitutive; degrees; stress	The effects of Ce and Y addition on microstructure evolution and precipitation of Cu-Mg alloy hot deformation were investigated by hot compression test in the 500-850 degrees C temperature range and the 0.001-10 s(-1) strain rate range. The influence of rare earth elements on true stress-true strain curves and microstructure evolution of Cu-Mg alloy were obtained, the deformation mechanism under various conditions was defined, and the critical strain of Cu-Mg, Cu-Mg-Ce, and Cu-Mg-Y alloys and the resulting precipitates were determined. Dynamic recrystallization dominated the deformation process at high temperature and low strain rate. Ce and Y significantly delayed dynamic recrystallization and improved flow stress and activation energy of Cu-Mg alloy. The critical strains for Cu-Mg, Cu-Mg-Ce, and Cu-Mg-Y alloys deformed at 700 degrees C and 0.1 s(-1) were calculated to be 0.075, 0.1, and 0.14, respectively. Precipitates appeared in the Cu-Mg-Ce and Cu-Mg-Y alloys deformed at 850 degrees C and 0.001 s(-1), which were determined to be Cu2Mg. In addition, CuP2 phase was found in both Cu-Mg-Ce and Cu-Mg-Y alloys deformed at 800 degrees C and 0.01 s(-1). Precipitates caused dislocation and grain boundary pinning. Furthermore, a large number of twins appeared in the Cu-Mg-Ce and Cu-Mg-Y alloys, which increased the number of grain boundaries and furthered grain refinement.
10.1016-j.jallcom.2018.12.099	-1		The stress-induced martensitic transformation of Cu50Zr50 at. % shape memory alloy was tuned through microalloying and co-microalloying. The effect of microalloying elements Co or Ni individually or combined (i.e., co-microalloying) was investigated and compared at the macro- and nanoscale. From nanoindentation experiments, change in the slopes of (P/h)-h curves, plastic index and recovery ratio after annealing were investigated: partial replacement of Cu by 1 at. % Ni was observed to promote twinning while for 1 at. % Co the twinning propensity decreased and co-microalloying using 0.5 at. % Co and Ni had an intermediate effect. The recovery ratio of the Cu50Zr50 alloy, calculated from the volume change of a residual indent after annealing at 400 degrees C for 5 min after annealing at 400 degrees C for 5 min increased from 15.6% to 19.5% when substituting Cu by 1 at. % Ni. These results, obtained at the nanoscale, are in agreement with macroscale test observation, namely, differential scanning calorimetry and x-ray diffraction. Therefore, microalloying opens up possibilities for the development of more cost-effective CuZr alloys, with a view to develop commercial actuators that could replace costly NiTi alloys in the near future.
10.1016-j.jallcom.2018.12.212	8	hot; deformation; strain; strain rate; dynamic; hot deformation; recrystallization; dynamic recrystallization; flow; rate; flow stress; compression; constitutive; degrees; stress	Hot deformation characteristics and dynamic recrystallization of Cu-3Ti-3Ni-0.5Si alloy were studied systematically in the range of 700-850 degrees C and at the strain rate of 0.01-10 s(-1). The results show that the peak stress increases with decrease of temperature or increase of strain rate. The stress values of true strain are used for constructing constitutive equations and the constitutive equation model can well predict the flow stress of the Cu-3Ti-3Ni-0.5Si alloy. The processing map based on the dynamic materials model is composed of a power dissipation map and an instability map and the processing map show that an appropriate hot working process is in the range of 750-800 degrees C and at the strain rate of 0.1 s(-1). After hot compressive deformation at 850 degrees C with different strain rates, the volume fraction of dynamic recrystallization decreases with increasing strain rate. The dislocation tangle and dislocation pile-up generate close to the precipitate. The recrystallized nuclei appeared on the surface of the coarse precipitates and a small number of recrystallized nuclei formed at the trigeminal boundary can effectively promote the growth of the dynamic recrystallized nuclei. The precipitation of Ni3Ti phase promotes the nucleation of dynamic recrystallization, and is beneficial for the formation of stability deformation domains. The precipitation of Ni2Si phase inhibits the occurrence of dynamic recrystallization, giving rise to the formation of instability deformation domains.
10.1016-j.jallcom.2018.12.222	-1		Copper is widely used in many applications due to its excellent electric conductivity, processing ductility and corrosion resistance. However, poor hardness and low strength are the major limitations of copper in many fields. Herein, we report a high-performance copper matrix composites prepared by powder metallurgy. The copper matrix composites were prepared by mixed acid treatment, molecular-level method, ball milling and spark plasma sintering (SPS) process. The fabrication, microstructure, mechanical properties and electrical conductivity of the composites were investigated. The results show that nano-Al2O3 can act as an active mixing agent to disperse CNTs in copper powders and increase the adhesion between CNTs and copper matrix in composites. Additionally, the uniform dispersion of Al2O3 and CNTs can restrict the grain growth and form a strong bonding interface. Thus, the synthesized Cu-1.5CNTs-0.5Al(2)O(3) composite displays the highest comprehensive performance, such as 131 HV hardness, 345 MPa ultimate tensile strength, 324 MPa yield strength, 13.8% elongation, and 50.6 MS/m (87.2%IACS) electrical conductivity. This work provides a feasible way to prepare high-performance copper matrix composites.
10.1016-j.jallcom.2018.12.250	-1		Thin films within the immiscible binary Cu-Mo system were synthetized by d.c. magnetron sputter co-deposition and studied over the entire composition range. In the as-deposited state, the alloy films present single-phase Cu(Mo) or Mo(Cu) solid solutions for low- or high Mo contents, respectively, or Cu- and Mo-rich dual-phase structures for intermediate Mo contents. Annealing up to temperatures of 500 degrees C was conducted to study microstructural stability, phase decomposition, stress, hardness, elastic modulus and electrical resistivity. The Cu(Mo) solid solution observed for low Mo contents provides remarkable thermal stability and improves the mechanical properties with a minimized impact on the electrical resistivity up to the investigated annealing temperatures. In contrast, the Cu- and Mo-rich dual-phase structures offer the possibility to benefit from the two constituents' thermo-mechanical properties within the miscibility gap; however, they are characterized by a reduced thermal stability. (C) 2018 Published by Elsevier B.V.
10.1016-j.jallcom.2018.12.292	12	thermodynamic; ternary; phase; data; experimental; equilibria; phase equilibria; liquid; binary; experimental data; calculated; phases; literature; model; calphad	Cu6Sn5 is a promising alternative material for commercial anode in lithium ion batteries. In this study, the thermal stability of ternary compounds in the Cu-Li-Sn system and equilibrium phase transition of Cu6Sn5 upon charge-discharge reaction are investigated by means of first-principles calculations and key experiments. The ternary phase diagram for the Cu-Li-Sn system at 0 K constructed by first-principles calculations exhibits that CuLi2Sn2, CuLi2Sn and Cu2LiSn are thermodynamically stable, but Cu6Li3Sn4 is thermodynamically metastable. In addition, calculated equilibrium reaction path and voltage curve of Cu6Sn5 electrode suggest that CuLi2Sn2 and Cu2LiSn firstly form before the well-known CuLi2Sn appears during lithiation. Vibrational free energy contribution is introduced to study thermal stability of ternary phases, which predicts that Cu6Li3Sn4 is thermodynamically stable above 148 degrees C. In order to verify our calculations, phase equilibria of eleven ternary alloys at 120 and 180 degrees C are investigated by means of X-ray diffraction, scanning electron microscopy and electron probe microanalyses. It shows that Cu6Li3Sn4 can decompose between 180 and 120 degrees C, which is consistent with our predictions in calculations. Thus, our study suggests that Cu6Li3Sn4 is metastable at room temperature and CuLi2Sn2, CuLi2Sn and Cu2LiSn can form during the electrochemical lithiation of Cu6Sn5 electrode.
10.1016-j.jallcom.2018.12.382	-1		In the search of enhancing the surface properties of metals, application of the friction stir processing (FSP) method could be a good choice. In this study, copper-TiO2 surface nanocomposite was successfully developed through FSP and the effects of pass number on its microstructure, mechanical properties, tribological and corrosion behavior were explored. To characterize the microstructure of the composites, optical microscopy (OM), and field emission scanning electron microscopy (FESEM) were utilized. Mechanical properties in the terms of microhardness and tensile test were investigated. Results showed that by increasing the pass number of FSP, a significant enhancement in mechanical properties of the samples has occurred. In comparison to the pure copper, the microhardness, yield and tensile strength values using 4-pass FSP were found to improve 77%, 33%, and 186%, respectively. In addition, increasing the FSP pass number led to the reduction of the sample's elongation. The wear properties of the surface composites were found to the great enhancement by increasing the pass number. In addition, the corrosion results showed that the surface nanocomposite after 4 passes FSP had much high corrosion resistance.
10.1016-j.jallcom.2019.01.022	-1		High loading of WC nanoparticles was successfully incorporated into the alloy system Cu-40 wt% Zn by molten salt stirring method. Given the energy balance of thermal energy, van der Waals interaction and inter-particle barrier, the expected pseudo-dispersion of WC was stable. In order to evaluate the materials functional applicability, the mechanical, electrical and anti-corrosion properties of fabricated Cu-40 wt% Zn/WC nanocomposite were measured and theoretically analyzed; with an increase of WC nanoparticles to 23.0 vol%, the microhardness increases to -200.00 HV and the Young's modulus to -179.00 GPa. Even though the electrical conductivity decreases to similar to 4.17 MS/m, the corrosion rate for Cu-40 wt% Zn/WC is significantly lowered (0.017 mm/yr for 12.5 vol% WC).
10.1016-j.jallcom.2019.01.153	-1		The Cu-13.5Al-4Ni-0.5Ti copper-based shape memory alloys (SMAs) were fabricated by selective laser melting (SLM). The parameters were optimized to obtain almost fully dense copper-based SMAs samples. The phases and microstructures were characterized and the tensile properties at room temperature and 200 degrees C were evaluated. The XRD results showed that only the beta 1' phase could be detected in the Cu-based SMAs, which was attributed to the extremely short solidification time for the precipitation of alpha and gamma(2) phases during SLM process. The grains were well refined and the average grain size was approximate 43 mu m, which was much smaller than that of the cast copper-based SMAs. The X-phase (Cu2TiAl) is observed, which is granular and size 20-50 nm. The Cu-13.5Al-4Ni-0.5Ti copper-based SMAs fabricated by SLM exhibited excellent mechanical properties at room temperature, which was higher than that of the cast copper-based SMAs. This is attributed to two aspects: (1) grain refinement, (2) suppress of brittle gamma(2) phase. Remarkably, the tensile test results at 200 degrees C showed both higher strength and elongation, which is attributed to the bcc structure of the parent phase and the stress-induced martensitic transformation at 200 degrees C. Meanwhile, the difference of microstructures and properties between SLM-fabricated Cu-based SMAs and casting Cu-based SMAs were analyzed and discussed in detail.
10.1016-j.jallcom.2019.01.169	-1		The morphology of the phase and the grain size generally have a significant influence on the mechanical properties of the alloy. (Cu-30Fe)-2X alloys also significantly have been affected by the morphology and solidification process of the phase. Compared with the Cu-30Fe alloy, which has a dendritic Fe phase due to the separation of meta-stable liquid phases, the addition of Si causes the formation of a spherical Fe primary phase with a fine size, and enhancement of the volume fraction of the secondary separated Cu phase in the formed Fe phase and primary a-Fe phase. Moreover, it leads to an implement of yield strength that is about 35% greater than a Cu-30Fe alloy. The addition of Nb and V resulted in the formation of coarse Fe units, which resulted in a decrease in the yield strength due to the concentration of stress. These results will be used as useful data for industrial applications aimed at controlling micro-structures and improving mechanical properties in alloy designs.
10.1016-j.jallcom.2019.01.255	-1		In this work, Cu-SiO2 and Cu-Cr metal matrix composites were fabricated by the powder metallurgy method. The morphologies, microstructures and tribological behaviors of the Cu-SiO2 and Cu-Cr interfaces were studied. The results indicated that the amorphous SiO2 in the vicinity of the Cu-SiO2 interface was transformed into cristobalite crystal after sintering. The interfaces of the fcc-Cu and cristobalite SiO2 were mostly incoherent interfaces. The Cu-Cr interface consisted of an interlaced bcc-Crrich multiphase and some microvoids. These microvoids were generated from the clustering of the vacancies resulting from the asymmetric mutual diffusion of Cu and Cr atoms. The vacancies present in the Cu-Cr interface provided an abundance of fast-diffusion channels for the O atoms, resulting in the presence of the Cr2O3 nanoparticles in the vicinity of the microvoids. The Cr2O3 nanoparticles enhanced the mechanical properties of the interface via the dispersion strengthening mechanism. When the indenter slid through the Cu-SiO2 and Cu-Cr interfaces, the penetration depth increased rapidly, and the friction coefficient first decreased and then rapidly increased. Both the Cu-SiO2 and Cu-Cr interfaces were easily broken during the sliding test. The interfaces were broken more severely at the higher load, thereby reducing the rate of the change in the penetration depth and friction coefficient during their dynamic damage process. (C) 2019 Published by Elsevier B.V.
10.1016-j.jallcom.2019.01.274	16	wear; composite; composites; powders; milling; particles; powder; wt; sliding; friction; hardness; matrix; mechanical; surface; properties	The present work describes the effect of processing route on the densification of W-10 wt% Cu nanocomposite. The spark plasma sinterability of the nanocomposites prepared through four different routes has been investigated. Out of the four routes, polyol process resulted in the highest density of 17.20 g/cc, which amounts to 99.7% of theoretical density. Mechanical milling was the second best yielding a density of 16.83 g/cc. The correlation between densification vis-a-vis mechanical and electrical properties were studied and it was observed that as the density increases, both mechanical strength and electrical conductivity increase.
10.1016-j.jallcom.2019.01.335	-1		A Cu-0.41Mg-0.06Ca (wt%) alloy was designed and prepared by melting and casting in air atmosphere, followed by equal channel angular pressing (ECAP) process up to 12 passes via Bc route at room temperature. The microstructure and properties of the alloy were investigated by means of hardness test, tensile test, electrical conductivity measurement and electron microscopes observation. After 12 ECAP passes, the initial coarse grains were refined significantly and the average grain sizes decreased to 0.57 mu m. The coarse Cu5Ca phase was also fragmented and had the sizes of about 1-3 mu m. The Cu-Mg-Ca alloy after 12 ECAP passes showed excellent comprehensive properties, with a yield strength of 619 MPa, an electrical conductivity of 67.86 % IACS and a total elongation of 10.4%. Compared with the Cu-Mg alloy under the same condition, the yield strength of the designed alloy after 12 ECAP passes was improved by 30 MPa and the electrical conductivity increased by 0.63 % IACS accompanied by almost same total elongation. The good comprehensive properties were attributed to the ECAP process and the addition of Ca. The ECAP process provided much high yield strength increments which accounted for more than 80% of the yield strengths after 12 ECAP passes. In addition, the addition of Ca in the Cu-Mg alloy promoted the grain refinement, improved the work hardening ratio, and increased the electrical conductivity. (c) 2019 Published by Elsevier B.V.
10.1016-j.jallcom.2019.02.196	-1		Cu-10Sn alloy with body-center-cubic (BCC) lattice structure was fabricated through selective laser melting (SLM). The geometry of SLMed BCC lattice Cu-10Sn alloy (rod diammeter similar to 300 mu m, length similar to 700 mu m) was in good agreement with the design model. Similar with the nearly full density Cu-10Sn alloy, columnar also constituted the majority parts of the lattice structure Cu-10Sn, but exhibited various morphologies due to the different grain growth orientation under thermal effect. The gowth orientation of columnar grain in the rods oriented to the as-fabricated layer due to the higher thermal conductivity of the as-fabricated layers.
10.1016-j.jallcom.2019.03.139	-1		This study investigates the effect, that replacing Zr in a glass-forming Cu47.5Zr47.5Al5 alloy by Sc (0-2 at%) has on the phase formation as well as on the thermal and mechanical properties. Even though it is not reflected in the thermal data, the glass-forming ability (GFA) is significantly reduced. This originates from the increased tendency to precipitate the shape-memory phase B2 CuZr(Sc), which, in turn, promotes the formation of bulk metallic glass (BMG) matrix composites. Sc appears to be very effective in stabilizing the B2 crystals because it forms the stable B2 CuSc phase with a similar lattice constant like B2 CuZr. By adjusting the casting parameters, the composite microstructure of Cu47.5Zr46.5Al5Sc1 can be controlled to a certain extent. The yield strength and the plasticity of the present composites depend on the crystalline volume fraction. In-situ high-energy X-ray diffraction reveals that deformation proceeds in three stages: (i) martensitic transformation of the B2 phase, (ii) yielding of the amorphous phase and continuing martensitic transformation, (iii) completion of the phase transformation and plastic deformation of all phases. Our work suggests that Sc is a promising candidate to adjust the microstructure and, thus, the mechanical properties of CuZr-based composites consisting of a glassy matrix and shape-memory crystals.
10.1016-j.jallcom.2019.03.388	0	solidification; phase; magnetic; magnetic field; undercooling; field; liquid; separation; peritectic; immiscible; cu-; dendrite; phase separation; microstructure; primary	In the present study, the Cu-24Pb-xSn (wt%) alloys with Pb-rich secondary phase particles (SPPs) in different morphology were prepared by intermediate frequency induction heating technology. The experimental results show that the SPPs transform from network to rod-like morphology with Sn content increasing from 0 wt% to 6 wt%. The relevant function mechanism of Sn addition was revealed through synchrotron X-ray radiography and thermodynamic analysis. It is indicated from the thermodynamic calculation that Sn addition can weaken the demixing tendency in Cu-Pb system. This can also lead to intensity drop of the monotectic reaction which was characterized by differential scanning calorimetry (DSC). Simultaneously, a triple-phase-coexistence (TRPC) region is introduced with Sn addition during solidification, which contains a Cu-rich liquid (L-1), a Pb-rich liquid (L-2) and a solid a-Cu (S). Benefitted from the mobility of these two immiscible liquids, L-2 tends to show regular rod-like morphology and finally transform to rod-like SPPs, which is similar to some immiscible alloys containing an immiscibility gap, such as Al-Pb, Al-Bi and Ti-Ag alloys. The width of TRPC region in the pseudobinary phase diagram of Cu-Pb-Sn alloy increases with increasing Sn content. This is attributed to the fact that increasing Sn content can lead to the drop of interfacial tension between L-1 and L-2. Simultaneously, the interfacial tension drop will decrease the Marangoni migration velocity of the SPPs, and the Marangoni migration serves as the main driven force of SPPs' collision and coagulation in this case. Therefore, Sn addition is helpful to obtain fine and dispersed SPPs in this case. This work possesses guiding significance to the composition design and production of relevant hypomonotectic alloy with homogeneous and refined microstructure.
10.1016-j.jallcom.2019.04.209	-1		Cu-Cr alloys with similar to 32 at% Cr were rapidly solidified by splat quenching or laser melting techniques with the intention to form a very fine grained, non-equilibrium nanostructure similar to those obtained by severe plastic deformation or thin film deposition. The rapidly solidified Cu-Cr alloys were analyzed by Xray diffraction, scanning electron microscopy and transmission electron microscopy. Both synthesis techniques lead to a similar two-phase microstructure with a nearly pure fcc Cu matrix with mm grain sizes and bcc Cr particles highly supersaturated with Cu. Splat quenching provides finer bcc particles with dimensions of less than 50 nm compared to laser melting with particle sizes of 100-2000 nm. In case of laser melting, (14 +/- 2) at% Cu are contained in the bcc phase, while splat quenching freezes (20 +/- 2) at% Cu in the bcc particles. The microstructures are discussed and compared to the non-equilibrium microstructures reported in literature using severe plastic deformation and thin films deposition.
10.1016-j.jallcom.2019.05.091	15	aging; strength; conductivity; electrical conductivity; electrical; mpa; treatment; strengthening; degrees; cu-; cold; precipitation; tensile strength; tensile; iacs	This study investigates the age hardening behavior of the cold rolled Cu-3Ti-3Ni-0.5Si alloy upon different deformations. The microstructure and the phase composition after precipitation were characterized by X-ray diffraction, optical microscopy, scanning electron microscopy, and transmission electron microscopy, and the electrical conductivity and mechanical properties of the alloy were tested as well. The as-cast Cu-3Ti-3Ni-0.5Si alloy consists of Ni2Ti phase, NiTi phase, and Cu matrix, and Ni2Si, Ni3Si, and Ni3Ti phases precipitated from the Cu matrix after aging treatment. TEM analysis shows that Ni2Si phase is coherent with the Cu matrix after 50% deformation and aging at 500 degrees C for 120 min, with an orientation relationship of [(2) over bar 01](Ni2Si) //[11 (1) over bar ]Cu. However, Ni2Si phase loses its coherence with the Cu matrix if the size of the Ni2Si phase is above 4.68 nm. Additionally, large deformation promotes most striped precipitates to transform into fine and spherical precipitates, so the appropriate deformation and aging temperature are beneficial for the improvement on the electrical conductivity and hardness. After 90% deformation and aging for 30 min at 500 degrees C, Cu-3Ti-3Ni-0.5Si alloy has a good combination of tensile strength, elongation, hardness and electrical conductivity, which are 615 MPa, 25.1%, 268 HV and 33.79 % IACS, respectively. The fracture morphology exhibits numerous fine equiaxed dimples with an average size of about 1 mu m, and small amounts of large dimples with an average size of about 10 mu m, and the assigned failure mechanism of the Cu-3Ti-3Ni-0.5Si alloy is a ductile fracture.
10.1016-j.jallcom.2019.05.129	-1		Hybrid copper matrix composites reinforced by TiB whiskers and TiB2 particles were fabricated by in situ mixing casting in combination with rolling and annealing. During turbulent mixing and copper mold casting processes, the in situ reactions carried out completely, and the macrosegregation of reinforcements in the composites was overcome efficiently. By controlling the rolling and annealing parameters, unfavorable casting defects, including chain-type reinforcement clusters and shrinkage porosities that formed during the end stage of solidification, were eliminated. Accordingly, the uniform distribution of hybrid reinforcements in the as-annealed composites provided good comprehensive performance. Compared to the 2.6 wt% TiB2p/Cu composite, the (1.0 wt% TiB2p-0.9 wt% TiBw)/Cu hybrid composite exhibited both higher strength (492 MPa) and higher electrical conductivity (85.5% International Annealed Copper Standard). Therefore, the hybrid effect in the copper matrix composites can be explained by the fact that a better strengthening effect was achieved by adding less hybrid reinforcement, which helped maintain the electrical conductivity at a relatively high level.
10.1016-j.jallcom.2019.05.135	15	aging; strength; conductivity; electrical conductivity; electrical; mpa; treatment; strengthening; degrees; cu-; cold; precipitation; tensile strength; tensile; iacs	The effects of Co on the Cu-Ni-Co-Si alloys' microstructure and mechanical properties were investigated. The Cu-1.5Ni-1.0Co-0.6Si and Cu-1.5Ni-1.5Co-0.6Si alloys with combined aging and 40-80% cold rolling were also investigated. The hardness, electrical conductivity, and microstructure were characterized, complemented by X-ray diffraction analysis and transmission electron microscopy. At 450 degrees C alloys aging, the aging precipitated phases are beta-Ni3Si and Co2Si. Specifically, the orthorhombic (Ni, Co)(2)Si precipitates were found, which have the same crystal structure as the Ni2Si precipitates. The crystal orientation relationship between the matrix and the precipitates is: [112] Cu//[112]beta//[012] p, (1 (1) over bar1)Cu//(1 (1) over bar1)beta//(021) p; [001] Cu//[001]beta//[001] p, (220) Cu//(110) beta//(100) p. With the increasing Co content, the properties of the alloy were degraded. However, Co can promote the growth of the precipitates and accelerate precipitation during the aging process. After aging at 500 degrees C for 2 h, the hardness and conductivity of the Cu1.5Ni- 1.0Co-0.6Si alloy with 40% deformation were 250 HV and 43% IACS, respectively.
10.1016-j.jallcom.2019.05.256	11	glass; bulk; metallic; bulk metallic; gfa; bmg; glassy; metallic glass; ability; bulk metallic glass; amorphous; addition; crystallization; mm; glass-forming	The effect of Fe-C alloy additions on thermal, mechanical and corrosive properties of (Cu50Zr40Ti10)(1) (-x)(Fe-C)(x) (x = 0-2.20 at%) alloys were systematically investigated. The results show that the Fe and C additions can enhance glass transition temperature T-g and onset crystallization temperature T-x , but narrow supercooled liquid region Delta T-x . Work-hardening can be clearly observed for the Cu-based bulk metallic glasses (BMGs) containing Fe and C elements. The yield strength (sigma(y)), fracture strength (sigma(f)) and plastic strain (epsilon(p)) are drastically increased by Fe-C alloy additions. The corrosion potential E-c increases and the corrosion current density i(c) decreases with increasing Fe and C contents. The studied Cu-based BMGs exhibit unique and novel anodic polarization behavior characterized by current platforms plus current serrations. The current serrations are much larger for the Cu-based BMGs with 0 <= x <= 1.32 at% than for those with 1.76 <= x <= 2.20 at%. The corrosion surface images are changed from the pits to the passive films by Fe-C alloy additions. The corrosion behavior gradually transforms from the pitting corrosion to the self-passivization with increasing Fe and C contents. The corresponding mechanisms are also discussed.
10.1016-j.jallcom.2019.05.271	-1		Alumina dispersion-strengthened copper (ADSC) alloy is a new materials widely used in lead frames, resistance welding electrodes, etc. The paper has systematically studied the strength and electrical conductivity behavior in situ reaction using rare-earth La and Ce. Solving the clustering on nanoparticles Al2O3 under spark plasma sintering (SPS) and addition of La and Ce for ADSC alloy is the significant differences. Specimen of Cu-0.7 wt% Al2O3 added with 0.7 wt% Ce does not present pores in SEM and BSE images due to special dispersed element Ce. A new ADSC alloy fabricated with Cu-0.7 wt%Al2O3-0.7 wt% Ce under SPS shows the high -strength and the high-conductivity. Nanoparticles Al2O3 encircled with nanoparticles CeO2 and Cu2O, which is generated in situ are evenly distributed in the Cu matrix, resulting in increasing strength . Lattice distortion does not occur in the new ADSC alloy. Cu atoms are replaced by Al generated in situ to form a solid solution with a face-centered cubic structure owing to the similar atomic radii and electronegativities of Cu and Al, resulting in increasing the electrical conductivity. Experimental results show that adding rare-earth metal nanoparticles Ce can significantly improve the properties of ADSC alloy.
10.1016-j.jallcom.2019.06.344	-1		Gas atomized Cu-3Ag-0.5Zr and Cu-3Ag-0.5Zr-0.4Cr-0.35Nb (wt%) powders were compacted by hot isostatic pressing (HIP) and followed by forging. The microstructures and tensile properties at room and elevated temperatures (400 degrees C, 450 degrees C and 500 degrees C) were investigated. The continuous Ag precipitates (5-25 nm) and Cu4AgZr (200-500 nm) particles are the main strengthening phases in the Cu-3Ag-0.5Zr alloy. The yield strength and ultimate tensile strength at room temperature are enhanced by 104 MPa and 83 MPa, respectively, due to the introduction of Cr2Nb (50-80 nm) particles. Besides, the strength at elevated temperatures is also improved. For both the alloys, the discontinuous Ag precipitates near the grain boundaries result in a weak grain boundary cohesion when tested at 450 degrees C, leading to the lowest elongation. The Cr2Nb and Cu4AgZr particles are extremely stable when tested at 500 degrees C, which benefits to the performance enhancements at elevated temperatures.
10.1016-j.jallcom.2019.07.073	-1		The heat resistance of copper alloys is desirable to improve while it services at high temperature as electrically and thermally conductive components. In present paper, the strengthening pattern of nickel-based superalloys is expected to be applied in copper alloys. Here the Cu50Ni37.5M12.5 (M = Al, Cr, Mo) alloys were prepared by vacuum arc melting and heat-treated in the corresponding conditions to obtain three different kinds of typical microstructure. The room temperature (RT) properties (hardness and resistivity) and high temperature properties (melting point, softening temperature and variable temperature resistivity) of the three alloys are contrasted and analyzed in detail. The Cu50Ni37.5Al12.5 alloy strengthened through the gamma' phase coherent precipitation shows the best conductivity and highest hardness (5.47 % IACS (International Annealed Copper Standard) and 310.1 HV). The splitting of the gamma' phase is contributing to hardening at high aging temperature. The resistivity-temperature behavior of the three alloys shows that the resistivity with rising temperature consists of the ideal lattice resistivity and the resistivity increment due to the defects. The Cu50Ni37.5Al12.5 alloy has the smallest room temperature resistivity and its resistivity maintains the lowest during the whole heating process (RT-1077K). Therefore, the coherent precipitated gamma' phase is expected to improve the heat resistance of the copper alloys while maintaining its electrical conductivity.
10.1016-j.jallcom.2019.07.245	16	wear; composite; composites; powders; milling; particles; powder; wt; sliding; friction; hardness; matrix; mechanical; surface; properties	In this work, Cu-10Sn/SiC composite has been manufactured using powder metallurgy method and its microhardness and corrosion resistance have been evaluated. For this, Cu-10Sn and SiC powders with various ratios were mixed, molded and sintered. Optical microscope, SEM and EDX were applied for study of SiC particles distribution in Cu-10Sn matrix and interfaces between them. Results of microhardness and electrochemical measurements revealed that incorporation of silicon carbide particles in Cu-Sn bronze matrix increase the microhardness and corrosion resistance and the composite containing 10 wt% SiC has the highest microhardness and corrosion resistance in 3.5 wt% NaCl solution. High hardness and chemical stability of SiC particles, perfect matrix/second phase particles interfaces and acceleration in protective layer nucleation and formation by incorporation of SiC particles in bronze matrix were recognized as the main reasons for these properties improvements. Above 10 wt%, incorporation of SiC particles lowers the microhardness and corrosion resistance due to the agglomeration of these particles and incomplete sintering of the specimens.
10.1016-j.jallcom.2019.07.327	-1		First principles calculations are used to elucidate the thermodynamic stability of Cu-Au alloys. Here, we particularly focus on the Au-rich compositions which lie extremely close to the convex-hull. We find that there are multiple metastable states that are superstructures of the layered L-10 Cu0.5Au0.5 ground state. We also examine the effect of epitaxy on the ordered ground states of Cu-Au phases when the underlying substrate is Au. We find that the Au-rich phases remain stable, depending on the growth planes, while the Cu-rich phases are destabilized. We relate these results to the dealloying and nucleation of Au-rich phases observed experimentally. We perform Nudged Elastic Band calculations in both ordered and disordered Cu-Au phases to determine the activation energies of diffusion. The ordered phases show unique minimum energy paths due to uniform local environments of the species, while the disordered phases show a distribution of transition states, governed by the local density and the local bonding environments of diffusing species.
10.1016-j.jallcom.2019.151743	4	transformation; martensite; martensitic; phase; shape; beta; memory; shape memory; temperature; temperatures; martensitic transformation; gamma; transformation temperatures; effect; thermal	Minimizing phase transformation (PT) hysteresis is of crucial importance for reliability of shape memory alloy (SMA)-based devices, where the lattice strain/stress caused by thermal hysteresis leads to functional degradation. As a result, understanding structural factors that control PT pathway is critical for development of materials with high reversibility. In this study, two distinct PT mechanisms (from gamma'(1) martensite to beta(1) austenite phase) in Cu-Al-Ni SMAs were revealed by in-situ TEM observation. A growth-dominant conventional PT mechanism shows in the fast quench sample, whereas a nucleation-dominant PT mechanism that suppresses interface propagation and induces high thermal hysteresis displays in the slow quench sample. By characterizing the atomic scale composition and microstructure we discover that slow quenching induces nanoprecipitation that changes chemistry of the matrix alloy, which in turn causes the higher PT hysteresis and temperature, while fast quenching avoids the formation of these nanoprecipitates. Our finding provides valuable insights into the fabrication of SMAs with better reliability.
10.1016-j.jallcom.2019.152675	-1		The effect of temperature on tribological properties of coarse grained (CG) and ultrafine-grained (UFG) Cu-Cr-Zr alloy processed via high pressure torsion (HPT) was investigated. Dominant wear mechanism depends on both temperature and microstructure of the alloy. Adhesive, abrasive and oxidative wear mechanisms are operative in all samples at room temperature. Adhesive wear mechanism is also operative at 200 degrees C. Oxidative wear is found to be another wear mechanism at that temperature. The breakdown of oxide layers generates spherical wear particles which activate another wear mechanism of three-body abrasive wear. Excessive oxide layer formation is observed at 400 degrees C. Thick oxide layer covers the worn surface and provides a wear-protective load-bearing layer which brings about high wear resistance at 400 degrees C especially for the CG samples.
10.1016-j.jallcom.2019.153112	-1		A Cu-0.41Mg-0.06Ca (wt%) alloy was processed by equal channel angular pressing (ECAP) for up to 12 passes via Bc route at room temperature, and its homogeneity was evaluated from three aspects of hardness, microstructure and crystallographic texture. The hardness was measured in detail on the whole transverse planes, and the microstructure and the crystallographic texture in the central and bottom regions on the transverse planes were investigated by electron backscatter diffraction (EBSD) technique. After 1 ECAP pass, the hardness in the central region was 9.4% higher than that in the bottom region; the microstructure in the central region consisted of the elongated grains, while that in the bottom region was composed of the slightly distorted grains; the crystallographic texture in the central region followed the ideal orientations of the ECAP crystallographic texture, nevertheless the crystallographic texture in the bottom region obviously deviated from any ideal orientation of the ECAP crystallographic texture. Then, with the increase of ECAP passes, the hardness and microstructure differences between in the two regions gradually weakened, and the deviation of the crystallographic texture in the bottom region gradually decreased. After 8 ECAP passes, the both regions showed the same hardness, the similar ultrafine-grained microstructure and the similar crystallographic texture. The difference formation should be attributed to the non-uniform strain caused by the friction between the sample and the die wall, rather than caused by the corner gap. The difference weakening should be attributed to the strain hardening behavior of metals. The strength calculation showed that the Cu-Mg-Ca alloy after 8 ECAP passes had almost the same yield strengths where 593 MPa for the central region and 583 MPa for the bottom region, showing only 1.7% difference.
10.1016-j.jallcom.2019.153123	-1		Cu-Cr-Zr alloys are often subjected to premature failures due to arc erosion at moment of their breakdown. In this paper, a series of simulated high-voltage arc ablation experiments were conducted to systematically investigate arc ablation characteristics of Cu-Cr-Zr alloys, their microstructure evolutions and anti-ablation properties after plastic deformation and microalloying. Results showed that during their arc ablation processes, a halo pattern was firstly formed on the surface under the action of high-temperature arc. This is followed by partial melting and splashing of Cu, forming of uneven and rough surfaces, and finally significant burning of the alloy. The degree of ablation of alloy is aggravated with the increased breakdown voltage. Due to a combined effect of solid solution strengthening, fine grain strengthening and deformation strengthening, the ablation resistance of the micro-alloyed and plastically deformed alloy has been significantly improved. The breakdown field strengths of commercial Cu -Cr-Zr alloy, heat-treated and deformed one, micro-alloyed and heat-treated one are 1.46 x 10(6) V/m, 1.67 x 10(6) V/m and 1.90 x 10(6) V/m, respectively. However, the breakdown strength of alloys after microalloying is unstable. Results show that there are no preferred phases for the first breakdown of arc ablation of Cu-Cr-Zr alloys. The second-phase particles with high-hardness and high-melting temperature hinder the splashing and flow of the molten copper, and inhibit the movement of the cathode spots during the ablation process.
10.1016-j.jallcom.2019.153263	16	wear; composite; composites; powders; milling; particles; powder; wt; sliding; friction; hardness; matrix; mechanical; surface; properties	The present study discusses the formation of surface micro-texture on flat samples of Cu-based and Ni-based alloys by two-step electrochemical dissolution. Prior to the electrochemical dissolution, laser marking only on the araldite coating has been carried out for effective dissolution of the selectively exposed metal surfaces along the laser cut regions. After second stage dissolution, the circular truncated conical grids with average base diameter of 210.7 mu m for the Cu-based alloy and truncated square pyramid like grids with base width of 203.2 mu m for the Ni-based alloy have formed. Similarly, maximum dissolution depths of 61.8 and 39.3 mu m for the Cu-based and Ni-based alloys, respectively, could be observed. Moreover, excellent hydrophobicity of the textured Cu-based as well as Ni-based alloys correlating to grid dimensions along with air entrapment beneath the water droplet has been analysed with the help of Wenzel and Cassie-Baxter models. Nano-hardness of the as-received alloys as well as the textured alloy surfaces shows minor variation. Similarly, the micrographs of the flat surfaces of the as-received alloys and cross-sectional microstructure of the textured alloys have also portrayed little difference suggesting negligible heat or stress affected zone after dissolution process. Moreover, the textured surfaces have showed significant increment in surface area: similar to 62.7% for the Cu-based alloy and similar to 71.4% for the Ni-based alloy as compared to the flat specimens.
10.1016-j.jallcom.2020.153733	-1		Effect of microalloying of boron (B) i.e., 0.02-0.15 wt% and the variation of composition of Al and Be from 11.3 to 11.9 wt% and 0.41-0.44 wt% respectively, has been investigated on the grain refinement and shape memory properties of polycrystalline Cu-Al-Be shape memory alloy. The tests have been carried out for microstructure, morphology, phases, crystal structure, phase transformation temperatures and shape recovery ratio. The investigation results in boron has strong impact on grain refinement with minimal addition, followed by Al and Be. AlB2 acts as heterogeneous nucleation site in grain refinement and it increases with increase in B and Al. Transformation temperatures increases with boron up to 0.08 wt% and then decreases, whereas increase in Al and Be decreases the temperatures. Doping and increasing of boron up to 0.15 wt% exhibits complete shape recovery, whereas Be < 0.42 wt% and Al < 11.8 wt% exhibits poor recovery ratio.
10.1016-j.jallcom.2020.153761	-1		In this work, several ultrafine-grained W-Cu composites were prepared by sintering at different temperatures of 1050 degrees C, 1150 degrees C, 1250 degrees C and 1350 degrees C of 2 h followed by traditional infiltration. The sintering kinetics of tungsten particles, as well as the resultant density, mechanical properties including hardness and compressive behavior, and electrical properties including electrical conductivity and arc erosion behavior of the infiltrated composites were investigated comparatively. Results revealed that the composite pre-sintered at 1250 degrees C with the highest tungsten particle contiguity of 0.45 exhibited the highest hardness of 272 HV and compressive strength of 894.0 MPa with a pronounced deformation plasticity; besides, the good sinterability of its microstructure contributed to a well dispersed arc spots over 50 times of electrical breakdown tests, resulting in a superior and reliable electrical breakdown strength of 5.66 x 10(7) V/m.
10.1016-j.jallcom.2020.154265	1	shape; memory; shape memory; damping; martensite; martensitic; damping capacity; transformation; capacity; strain; superelasticity; temperature; cu-al-mn; shape memory effect; effect	The operation temperature window is one of the key parameters for the refrigeration application of elastocaloric materials. In the present work, we investigated the relationship between the operation temperature window of the elastocaloric effect and composition in Cu-Al-Mn shape memory alloys (SMAs) by clarifying the effects of composition on the transformation temperature, martensite transformation-dislocation slip transition temperature (TMT-Ds), and adiabatic temperature change (Delta T-exp). A high Delta T-exp of 17.0 K, a high transformation entropy change (Delta S-exp) of 21.60 J/kg K and a wide temperature window over 262 K were measured in columnar-grained (CG) Cu-Al-Mn SMAs. A stable refrigeration capability of similar to 3500 J/kg and an adjustable temperature window covering a very large range of 50-450 K were also found in CG Cu-Al-Mn SMAs, which ensures potential for solid-state refrigeration applications and provides references for device design.
10.1016-j.jallcom.2020.154285	-1		This paper aims to explore the effects of C addition on the formed microstructure in undercooled Cu-Fe alloys. C addition changed the microstructure morphology and phase composition of the undercooled Cu-Fe alloys due to striking entropy changes. The composition analysis indicated that C was dissolved in both Fe-rich and Cu-rich phases, but the C content in the Cu matrix was lower than that in the Fe-rich phase. The addition of C element significantly improved the miscibility between the separated Fe-rich phase and the Cu-rich phase, thus resulting in the Fe-rich particles from the liquid phase separation disappearing in Cu-10Fe-2C alloy microstructure.
10.1016-j.jallcom.2020.154350	-1		The combination of selective laser melting (SLM) and Cu-based alloys has attracted attention in recent years due to the increasing requirements for components characterized by complicated structures and high electrical and thermal conductivity. In this paper, to investigate the forming properties of a Cu-Cr -Zr alloy in SLM, a statistical model regarding the impacts of the processing parameters on the density was established via an experimental approach (response surface method and analysis of variance). Furthermore, based on the acquired optimal processing parameters, samples with nearly full density and standard tension specimens were fabricated, and their microstructures and mechanical properties were analyzed. X-ray diffraction results indicate that the phase composition of the as-built sample by SLM contains only alpha-Cu phase and the Bragg peaks of the alpha-Cu phase in SLMed sample distinctly differs from those of powders and of wrought copper alloy. Compared with wrought copper alloy, SLMed Cu-Cr-Zr shows a comparable ultimate tensile strength (similar to 321 MPa); however, its elongation at break (25%) is much higher than that of wrought sample (15%). In addition, according to electron back-scattered diffraction analysis, a strong texture with respect to the <110> direction parallel to the building direction arose during SLM process.
10.1016-j.jallcom.2020.154726	-1		This paper presents the results on the influence of thermo-mechanical treatment on the electrochemical behavior of cast and sintered Cu-4at%Au alloy. The results were obtained by using both open circuit potential measurement and cyclic voltammetry in a NaOH solution. The microstructural and the mechanical properties were concurrently investigated. The thermo-mechanical treatment included pre-final rolling, solution annealing followed by quenching, final rolling, anneal hardening, and recrystallization annealing. Depending on the thermo-mechanical treatment, various microstructures were obtained, as a result different mechanical and electrochemical properties were attained. The anneal-hardened samples had the highest mechanical properties, as well as the most positive open circuit potential values. According to the cyclic voltammograms, the finally rolled samples had the best corrosion resistance compared with the samples taken after other steps of the thermo-mechanical treatment. The additional annealing contributed to a decrease in the corrosion resistance. After every stage of applied thermo-mechanical treatment the cast alloys exhibited a lower corrosion resistance than the sintered ones, since the corrosion rate increased with an increase in average grain size.
10.1016-j.jallcom.2020.155212	-1		The compatibility between Cu and liquid Li directly affects the safety of fusion devices. In this work, we investigated the compatibility between Cu Sigma 3 (111), Sigma 3 (112) and Sigma 5 (310) symmetrical tilt grain boundaries (STGB) and liquid Li using molecular dynamics (MD) simulation. The Li atoms rapidly penetrate the intergranular area along Sigma 3 (112) and Sigma 5 (310) grain boundaries (GBs), resulting in the formation of liquid grooves at the junctions of GBs and solid-liquid interfaces. However, the Sigma 3 (111) GB shows its resistance to Li penetration. In addition, the interfacial alloying and dissolution of Cu atoms are accelerated by Sigma 5 (310) GB via promoting the escape of Cu atoms. Then we calculated the potential energy distribution of Cu atoms which indicates the liquid metal embrittlement (LME) effect exists between Cu bicrystal and liquid Li. And we demonstrate this embrittlement has a strong correlation with the vacancy formation energy and the segregation energy of Li atoms. Comparing with the experimental results, our simulation results explain the corrosion morphology of polycrystalline Cu in liquid Li, and point out that the LME is the root cause of Cu specimen fragmentation.
10.1016-j.jallcom.2020.155266	-1		The advantages of Cu-based shape memory alloys (SMAs) over the more popular Ni-Ti alloys are their low cost and easy processability coupled with good electrical and thermal conductivity. However, these alloys suffer from severe brittleness due to highly ordered structure causing difficulty in cold working; consequently, their applicability in the form of wires and sheets is impeded. In an attempt to improve the ductility of these alloys, varying amounts of Nb and Ag were added to Cu-12Al-4Mn, a known SMA, and the effect of these additives on the shape memory properties as well as the microstructure through grain refinement were analyzed. Detailed microstructural observations indicated that the addition of more than 2 wt% of Ag or Nb was detrimental to the martensitic structure that was formed on quenching. Furthermore, the addition of Nb led to the formation of a more desirable martensitic microstructure, namely the fine beta'(1) phase, whereas the inclusion of Ag caused the formation of the coarse gamma'(1) phase. Based on the observed strength and shape memory effect, it was concluded that Nb significantly improved the mechanical as well as the shape memory properties of the base alloy.
10.1016-j.jallcom.2020.155275	-1		To understand the effect of Co addition on the modulated structure coarsening and discontinuous precipitation (DP) growth kinetics of Cu-15Ni-8Sn alloy, the experiments are carried out using optical microscope (OM), scanning electron microscope (SEM) and transmission electron microscopy (TEM). Our results showed that the addition of Co in Cu-15Ni-8Sn alloy did not recover with a new second-phase associated with Co. During the aging treatment process, the addition of Co reduced the coarsening kinetics of the modulated structure, which was related to the equilibrium solid solubility (X-e) of Ni and Sn in Cu, diffusion coefficient of Ni and Sn in Cu (D), and to the interfacial energy (sigma) of alpha-Cu matrix/L1(2). The decrease in values of Xe, D and sigma were resulted in a slowdown of the coarsening kinetics. Further, the suitable addition of Co significantly inhibited the nucleation and growth of discontinuous precipitation (DP). The growth kinetics of DP for Cu-15Ni-8Sn-xCo alloy were evaluated using the Johnson-MehlAvrami-Kolmogorov equation. With the combination of the Arrhenius equation, the activation energies (Q) of the samples were 105.45 kJ/mol, 150.76 kJ/mol, 178.44 kJ/mol, 251.53 kJ/mol, and 148.89 kJ. Compared with cobalt-free alloy, cobalt-containing alloys exhibited greater activation energy, which suggested that the addition of Co can greatly inhibit the formation of DP. Furthermore, the addition of Co led to decrease in the thickness of the grain boundary and increase in the interlamellar spacing of the DP, which were considered to be the main reasons for suppressing the growth of DP.
10.1016-j.jallcom.2020.155502	0	solidification; phase; magnetic; magnetic field; undercooling; field; liquid; separation; peritectic; immiscible; cu-; dendrite; phase separation; microstructure; primary	In this work, the influence of 10 T high magnetic field on the liquid-liquid phase separation behavior of Cu-33.33 at%Co immiscible alloy was systematically investigated. The results show that the separation behavior was significantly altered via the application of a high magnetic field. Both the Co-rich phase and the non-ferromagnetic Cu-rich phase are found to be elongated along the magnetic field direction due to the action of static magnetic energy and the coordinating of deformation. The relatively homogeneous microstructure of uniform dispersion of Co-rich phase on the matrix is obtained in the direction perpendicular to the magnetic field. The drag force induced by the thermoelectric magnetic convection under a high magnetic field hinders the solute transport of Co-rich phase, leading to a decline in the number of Cu-rich phase produced by the secondary decomposition. Moreover, the applied high magnetic field results in the variations of the undercooling during rapid solidification. The finally solidified Cu -Co alloy in a magnetic field of 10 T with higher undercooling exhibited a slightly lower saturation magnetization and higher coercivity and residual magnetizations. The present research provides new insights into the influence of high magnetic field on the liquid-liquid phase separation behavior of immiscible alloys.
10.1016-j.jallcom.2020.155762	15	aging; strength; conductivity; electrical conductivity; electrical; mpa; treatment; strengthening; degrees; cu-; cold; precipitation; tensile strength; tensile; iacs	The effects of minor rare earths, such as Sc, Er, and Y, on the microstructure and properties of Cu-Cr-Zr alloys, were studied systematically. Microstructure evolutions and properties variations of Cu-Cr-Zr-(X) alloys indicate that the hot-rolling + solid solution treatment + cold-rolling + aging treatment is an appropriate method to fabricate studied Cu-Cr-Zr-(X) alloys with high ultimate tensile strength, high electrical conductivity, excellent plasticity, and large strength-elongation products. The addition of Y effectively suppressed the precipitation and growth of Cr particles in the Cu-Cr-Zr-Y alloy. The high-temperature ultimate tensile strength of the peak-aged Cu-Cr-Zr-Y alloy was 381 MPa at 450 degrees C, and that of the over-aged one was 341 MPa, which are much higher than those of the Cu-Cr-Zr alloy in the peak-aged temper (320 MPa) and the over-aged temper (300 MPa). The primary strengthening mechanism in the high strength Cu-Cr-Zr-Sc alloys is the grain boundary strengthening following the HallPetch relationship. The mainly strengthening mechanisms in the Cu-Cr-Zr, Cu-Cr-Zr-Y, and Cu-Cr-Zr-Er alloys are precipitation strengthening and dislocation strengthening. These findings indicate rare earth elements play important roles in improving the high/room temperature properties of Cu-Cr-Zr system alloys. (C) 2020 Published by Elsevier B.V.
10.1016-j.jallcom.2020.156006	-1		The effect of inclusion on the strength and conductivity of fully discontinuous precipitated Cu-Ni-Si alloys with and without inclusion was studied. No inclusions were observed in Cu-4.75Ni-1.13Si alloy, the Ni + Si content of which was close to the solubility limit, while they were formed in solution-treated Cu-6Ni-1.42Si alloy at 980 degrees C. The duration of aging for full discontinuous precipitation (DP) at 500 degrees C was found to be shorter in Cu-6Ni-1.42Si alloy than Cu-4.75Ni-1.13Si alloy. The strength/conductivity of Cu-6%Ni-1.42%Si alloy with inclusion was 1071 MPa/46% IACS, while it was 966 MPa/50% IACS for Cu-4.75Ni-1.13Si alloy without inclusion, after drawing to the strain of 4. The drawing-induced uni-directional alignment of fiber-like Ni2Si precipitates was believed to increase the conductivity of Cu-Ni-Si alloys by reducing the cross sectional area of lamellar precipitates for the passage of electrons. The increase in strength was possibly due the higher volume fraction of fiber-like Ni2Si precipitates, along with the smaller inter-distance between them, in Cu-6%Ni-1.42%Si alloy with inclusion, than Cu-4.75Ni-1.13Si alloy without inclusion.
10.1016-j.jallcom.2020.156126	-1		The thermodynamic and kinetic properties of Cu45.6Zr45.3Al9.1, Cu47.5Zr45.1Al7.4, and Cu47.3Zr45.8Al6.4Sn0.5 bulk metallic glasses are investigated to help understanding the origin of the glass-forming ability in the Cu-Zr-Al(-Sn) glass-forming system. The thermodynamic driving force for crystallization is determined by using specific heat capacity data and several thermodynamic parameters, e.g., enthalpies and entropies, measured via differential scanning calorimetry and differential thermal analysis. Moreover, a thermomechanical analyzer and a custom-built Couette rheometer were used to measure shear viscosity and to determine the fragilities in the low-and high-temperature regimes, close to the glass transition and in the stable melt respectively. For each alloy, the thermodynamic driving force and low-temperature fragility exhibit good correlation with the critical casting diameter. Melt viscosity was measured up to approximately 150 K above the liquidus temperature, i.e., from 1100 K to 1350 K. At temperature above 1350 K, reactions between the graphite crucible and the melt were observed to occur and may interfere with the viscosity measurement. Considerable differences in fragility between the stable melt and the deeply supercooled liquid were observed and discussed in terms of a fragile-to-strong crossover.
10.1016-j.jallcom.2020.156197	-1		External oxidation was adopted to fabricate Cu-Al2O3 composites with Ag addition. The influences of Ag on oxidation kinetics, microstructure evolution and properties of Cu-Al2O3 composites were investigated by scanning electron microscopy (SEM), X-ray diffraction (XRD) and optical microscopy (OM). The external oxidation was found to be the combination of surface oxidation and internal oxidation. The parabolic rate constant (PRc), which can reflect the oxidation rate during the internal oxidation process, was analyzed by experimental measurement and theoretical calculation. The measured PRc results during external oxidation have increased by 81% to 2.14 x 10(-8)cm(2)/s at 1073 K and 71% to 2.63 x 10(-7) cm(2)/s at 1223 K after Ag was added. It indicates that the Ag can remarkably accelerate the internal oxidation process in external oxidation. Moreover, compared with traditional internal oxidation method, the external oxidation was found to be a more efficient way to prepare Cu-Al2O3. The PRc in traditional internal oxidation are 3.58 x 10(-9) cm(2)/s at 1073 K and 6.72 x 10(-8)cm(2)/s at 1223 K, while the PRc in external oxidation are much higher which are 1.18 x 10(-8)cm(2)/s at 1073 K and 1.54 x 10(-7) at 1223 K. SEM results show that the oxide bands composed of coarsening Al2O3, have disappeared, and the size of Al2O3 precipitates dropped from -65.78 nm to -45.42 nm after Ag was added. Due to the more homogeneous microstructure caused by Ag, the electrical conductivity had a 9.48% increment to -85.27% International Annealed Copper Standard (IACS), and the microhardness climbed from -131.8 HV to -152.76 HV.
10.1016-j.jallcom.2020.156275	-1		The present study investigated the aging precipitation behavior and mechanical, electrical properties of Cu-15Ni-8Sn alloy affected by cold rolling with different deformations. During cold rolling, the grain is elongated gradually along rolling direction with increasing deformation, simultaneously accompanied by the occurrence of a great deal of dislocations and deformation twins. During aging process, the coherent DO22 and L1(2) ordered phases precipitate successively from the matrix after 90% rolling deformation and aging treatment at 400 degrees C for 0.5 h with the orientation relationship of ((1) over bar 10)(DO22) // (02 (2) over bar)(Cu), [111](DO22) // [211](C)(u); (1 (11) over bar)(γ′) // (1<(<)over bar>(11)over bar>)(Cu), [211](γ′) // [211](C)(u). However, discontinuous precipitation (DP) behavior is significantly accelerated by prior cold rolling. On the one hand, by revealing the underlying growth kinetics of DP, it can be found that the nucleation sites of DP transform from grain edges to grain boundaries gradually with increasing rolling deformation. On the other hand, the nucleation sites and nucleation rate of DP can be enhanced greatly with increasing dislocation density. Furthermore, the interlamellar spacing of DP slightly increases and the morphology transforms from lamellar structure to bush-like structure gradually with increasing rolling deformation. In addition, the hardness, tensile strength and electrical conductivity are obviously improved while the peak aging time greatly shortens with increasing rolling deformation. The optimal combination of properties with a hardness of 409 HV, a yield strength of 1256 MPa, and an electrical conductivity of 7.5 %IACS can be obtained in the sample with 90% rolling deformation after aging treatment at 400 degrees C for 0.5 h . The corresponding strengthening mechanism and conductive mechanism were discussed. It can be discovered that the precipitation strengthening, dislocation strengthening and solid solution strengthening are believed to be the main strengthening mechanisms to enhance the alloy strength . (C) 2020 Published by Elsevier B.V.
10.1016-j.jallcom.2020.156555	-1		The demand for using high-performance Cu matrix composites in the electronic industry has recently increased rapidly owing to the low strength and tribological properties of pure copper. Accordingly, research and development of composite processing and related properties have increased. In this study, the Cu matrix was reinforced with different amounts of TiB2 particles by mechanical alloying of elemental powders followed by consolidation employing spark plasma sintering (SPS) whereby high relative density (similar to 99%) and electric conductivity (similar to 83-88% IACS) were obtained. Tensile properties and deformation mechanisms of the composites were studied utilizing conventional and in-situ tensile tests with simultaneous FESEM and EBSD observations. In comparison with the reference pure copper, it was found that adding 0.5 wt%TiB2 results in significant ductility increment, which was consistent with the longer strain-softening behavior observed after necking. In addition, using in-situ microstructure characterization, twinning with slip bands were confirmed as deformation mechanisms. By increasing the amount of reinforcement to 5 wt%TiB2, strengthening was remarkable while sustaining a considerable elongation. The Hall-Petch and dislocation strengthening mechanisms were the key models of strengthening based on the calculations and microstructure characterizations since by increasing the TiB(2 )particles, significant grain refinement and dislocation density were shown.
10.1016-j.jallcom.2020.156560	1	shape; memory; shape memory; damping; martensite; martensitic; damping capacity; transformation; capacity; strain; superelasticity; temperature; cu-al-mn; shape memory effect; effect	This study investigates the effect of Co additions on the damping properties of Cu-13.5Al-4Ni-xCo and Cu-14.0Al-4Ni-xCo (x = 0-2 wt%) shape memory alloys (SMAs). The Cu-14.0Al-4Ni SMA exhibits a higher inherent and intrinsic internal friction (IFPT + IFI) peak than the Cu-13.5Al-4Ni SMA, but its (IFPT + IFI) peak temperature is below 0 degrees C. Adding Co into the Cu-14.0Al-4Ni SMA can effectively increase the (IFPT + IFI) peak temperature and reduce the grain size of the alloys. The grain size of the Cu14.0Al-4Ni-xCo SMAs decreases from approximately 300 um to below 50 um when the Co content increases from 0 to 2 wt%. The (IFPT + IFI) peak temperature for the Cu-14.0Al-4Ni-xCo SMAs increases from -0.1 degrees C to 77.7 degrees C when the Co content increases from 0 to 1 wt%, but their tan delta values decrease from 0.0402 to 0.0090 simultaneously. The Cu-14.0Al-4Ni-2Co SMA does not exhibit an observable (IFPT + IFI) peak. The tan 6 values of the (IFPT + IFI) peaks decrease with increasing Co content because the movements of the parent/martensite phase interfaces and twin boundaries are impeded by the increased amounts of grain boundaries and gamma(2) phase precipitates. Among these Cu-Al-Ni-Co SMAs, the Cu-14.0Al-4Ni-0.5Co SMA is more suitable for high-damping applications as it possesses an (IFPT + IFI) peak with tan 8 close to 0.02 at approximately 50 degrees C.
10.1016-j.jallcom.2020.156775	13	clusters; atomic; glass; atoms; composition; dynamics; metallic; icosahedral; glasses; simulations; molecular; cu-zr; molecular dynamics; metallic glasses; structural	Detailed information on the atomic arrangement of glassy Cu54Hf46, Cu61Hf39 and Cu69Hf31 alloys has been obtained by the reverse Monte Carlo (RMC) simulation using high-energy X-ray diffraction and neutron diffraction data as input. Dominant cluster units are identified by means of the radical Voronoi tessellation technique. Cu-centred clusters show a stronger ordering level than the Hf-centred ones. Results are compared with those previously reported for analogous binary amorphous systems such as Zr-Cu and Zr-Ni. Additionally, the thermal stability of the studied Cu-Hf alloys has been inspected by in-situ high-temperature X-ray diffraction and differential scanning calorimetry measurements. A different structural evolution is observed for Cu69Hf31 compared with Cu54Hf46 and Cu61Hf39. Products of devitrification are identified and quantified. The better glass forming ability of Cu54Hf46 and Cu61Hf39 compared with Cu69Hf31 is explained in the view of short range order differences of glassy states and corresponding crystalline phases formed during devitrification.
10.1016-j.jallcom.2020.156776	15	aging; strength; conductivity; electrical conductivity; electrical; mpa; treatment; strengthening; degrees; cu-; cold; precipitation; tensile strength; tensile; iacs	The microstructure and properties of Cu-0.42Cr (wt%) and Cu-0.45Cr-0.14Ti (wt%) alloy subjected to cold rolling and aging treatment are investigated through tensile testing, electrical conductivity measurement, scanning electron microscopy, and transmission electron microscopy. Results show that the tensile strength of Cu-0.45Cr-0.14Ti (wt%) alloy enhances as the degree of deformation increases, but the degree of deformation slightly influences electrical conductivity. When deformation is changed, electrical conductivity is basically unchanged. The good combination of strength and electrical conductivity, which reach 610 MPa and 55.4% IACS, respectively, can be obtained in the Cu-0.45Cr-0.14Ti (wt%) alloy after 80% cold rolling and aging at 450 degrees C for 15 min. Ti inhibits the growth of the Cr precipitation phase and enhances the precipitation strengthening effect. Ti mainly exists in the matrix in the form of solute atoms, which do not form a separate lattice structure after aging treatment.
10.1016-j.jallcom.2020.156893	-1		In this work, the microstructural evolution and strengthening mechanisms of pure copper and Cu-Ag alloys subjected to cold rolling were experimentally investigated. Significant strain strengthening occurred during cold rolling, with steady-state strengths of 424, 666, and 686 MPa achieved upon large-strain cold rolling in pure copper, Cu-10Ag, and Cu-15Ag, respectively. Microstructural examination was performed to quantitatively determine the strengthening contributions of the grain boundaries, dislocations, Ag dispersoids, and solute atoms. Dislocation strengthening and boundary strengthening were shown to be the dominant strengthening mechanisms in the cold-rolled Cu-Ag alloys at steady state, accounting for >80% of the strengthening. In addition, Ag addition increased the limiting concentration of dislocations and subgrain boundaries in the Cu solid solution, resulting in higher steady-state strength of the cold-rolled Cu-Ag alloys relative to that of pure copper. The high Ag concentration also led to a larger volume fraction of the high-strength eutectic colony in Cu-15Ag, resulting in higher strength than that of Cu-10Ag.
10.1016-j.jallcom.2020.156958	10	composites; nanoparticles; strength; matrix; high; strengthening; particles; conductivity; composite; electrical; mpa; sintering; ods; grains; mechanical	In this work, a one-step thermal plasma synthesis route was developed to construct core-shell W-Cu nanoparticles with size about 30 nm. As synthesized nanocomposite powders address the issues of homogeneous elemental distribution and short diffusion distance for Cu to form network around W grains, facilitating fast densification with uniform microstructure and suppressed W grain growth . As a result, compact with high relative density of 99.31% and grain size of 260 nm was obtained at low temperature of 1100 degrees C, further led to the recorded hardness of 562 Vickers-hardness (HV) and electrical conductivity of 54.32% International Annealed Copper Standard (IACS), respectively.
10.1016-j.jallcom.2020.157004	15	aging; strength; conductivity; electrical conductivity; electrical; mpa; treatment; strengthening; degrees; cu-; cold; precipitation; tensile strength; tensile; iacs	The mechanical properties and microstructure of Cu-Cr and Cu-Cr-Ti alloys after aging treatment were investigated via hardness measurements, electron backscattered diffraction analysis, and transmission electron microscopy. The results show that the hardness, yield strength, and softening temperature of the Cu-Cr-Ti alloy significantly improved. The interface of the Cu matrix and Cr-rich precipitates was semi-coherent as determined by calculations, and the strengthening mechanism of the Cr precipitates was via the Orowan strengthening relation. A high dislocation density was observed in the matrix, which was because of impediment by fine Cr precipitates in the Cu-Cr-Ti alloy. The effects of dislocation strengthening, solid-solution strengthening, and precipitate strengthening were shown to remarkably enhance the yield strength .
10.1016-j.jallcom.2020.157006	2	corrosion; surface; film; electrochemical; films; spectroscopy; layer; current; solution; potential; resistance; composition; x-ray; ions; showed	Cu-Sn alloy foams, with an open-cell structure, were fabricated by Cu/Sn coelectrodeposition onto a polyurethane (PU) template in an alkaline electrolyte with a citrate complexing agent before undergoing a subsequent thermal treatment for PU removal in a N-2 gas environment. These foams were predominantly comprised of a Cu matrix along with Cu6Sn5 and Cu3Sn intermetallic compounds, which are known as active materials in Cu-Sn alloy electrodes used in rechargeable batteries. The chemical phase change of Cu-Sn alloy foams and its influence on the electrical resistance were studied according to the heating temperature and N-2 gas flow rate. Assuming the thermal degradation of PU as a first-order reaction, the dependence of the PU removal process on the heating temperature was also theoretically investigated. In addition, a postannealing process of the Cu-Sn alloy foams was employed to reduce their electrical resistance by promoting grain growth .
10.1016-j.jallcom.2020.157174	-1		In the present study, bulk nanocrystallineCu(99.5)Zr(0.5), Cu99Nb1.0, and Cu(98.5)Zr(0.5)Nb(1.0)alloys have been synthesized by using mechanical alloying followed by hot pressing (HP) at 550 degrees C. Further, these asfabricated alloys were annealed at 800 degrees C and 900 degrees C for 1 h to investigate the structure-property correlation. Grain size and phase identification has been carried out using X-ray diffraction (XRD) and transmission electron microscopy (TEM). While mechanical properties were investigated using Vickers hardness and shear punch test (SPT). The grain size of the as-processed alloys was found to remain nanosized 41 +/- 2.2 nm in Cu99.5Zr0.5(CZ), 50 +/- 1.5 nm in Cu99Nb1.0(CN) and 26 +/- 1.2 nm in Cu98.5Zr0.5Nb1.0(CNZ) even after annealing at 900 degrees C. This is attributed to the stabilization of the nanosize grains by segregation of solute atoms (Nb and Zr) along grain boundaries and/or Zenner pinning by intermetallic precipitates like Cu5Zr in CZ and CNZ alloys.
10.1016-j.jallcom.2020.157372	-1		Cu-Z n-Sn ternary phases were synthesized by high-temperature solid-state synthesis. Structural characterization was performed by means of X-ray diffraction and energy dispersive X-ray analysis. The ternary compounds were found to adopt gamma-brass (Cu5Zn8) structure type. X-ray diffraction analyses show that 7-brass type phases in Cu-Zn-Sn system crystallize in P (4) over bar 3m space group (cP52, 215). Ternary Cu-Zn-Sn gamma-brass type phases exist in an extended homogeneity range. The phase-pure ternary compounds are found to exist for compositions ranging between 48 and 70 atomic % Cu, between 15 and 46 atomic % Zn, and between 5 and 15 atomic % Sn. The phase width arises due to the statistical distribution of constituent elements, which is typical for intermetallic compounds. The Cu-Zn-Sn gamma-brass structures consist of two compositionally different 7-clusters (consists of the four polyhedral shells: inner tetrahedron (IT), outer tetrahedron (OT), octahedron (OH), cuboctahedron (CO)) centered at high symmetric sites in a primitive cubic unit cell. The gamma-brass cluster (A) at (0,0,0) site is Cu-rich, chemically more ordered than the cluster (B) present at (1/2,1/2,1/2). For A cluster, only IT site is mixed (Zn/Sn) and OT, OH, CO sites are exclusively occupied by Cu, throughout the entire homogeneity range. The B cluster is heavily disordered; only the OT site is exclusively occupied by Cu all over the phase region. For Zn rich region IT site is fully occupied by Zn, then mixed occupied between Cu and Zn at intermediate Zn-concentration, and completely occupied by Cu at Cu-rich side of the Cu-Zn-Sn phases. OH site is fully occupied by Zn at Zn rich side. The same site is mixed occupied between Cu, Zn and Sn for the composition at intermediate Zn-concentration and Cu/Sn at Zn poor side. CO site of B cluster is occupied by Zn and Sn. The electrochemical properties of four Cu-Zn-Sn based samples with different compositions were studied as an anode material for lithium and sodium-ion storage using galvanostatic charge-discharge cycles. Li-ion half-cells transpired excellent retention of charge capacity (>80%) with more than 99% Coulombic efficiency. The results further encourage the prospects of ternary Cu-Zn-Sn alloy anodes to utilize in real energy storage applications. (C) 2020 Published by Elsevier B.V.
10.1016-j.jallcom.2020.157373	12	thermodynamic; ternary; phase; data; experimental; equilibria; phase equilibria; liquid; binary; experimental data; calculated; phases; literature; model; calphad	The Cu-Te binary system is of a significant interest due to the existence of Cu2Te superionic conductor in the thermoelectric application. The phase equilibria have been investigated by means of experiment and thermodynamic modeling. Based on the critical literature review on the available phase diagram and thermodynamic data, 16 crucial alloys are prepared and the phase relations in the as-cast and annealed status analyzed using X-ray diffraction (XRD) and electron probe microanalysis (EPMA). Moreover, a simultaneous differential scanning calorimetric and thermogravimetric (DSC-TG) analyses technique is utilized to confirm temperatures of invariant reactions, as well as the polymorphic transitions in the intermetallic compounds Cu2Te, Cu4Te3 and CuTe. There are five variants in the Cu2Te. A thermodynamic optimization of the Cu-Te system is then conducted with the support of the assessed literature data and the present experimental results. The liquid phase is described by the associate model due to the chemical short-range order and Cu2Te, Cu4Te3 and CuTe are treated as stoichiometric compounds in the present optimization. A set of self-consistent thermodynamic parameters are finally constructed. The present calculations are in good agreement with the available experimental data.
10.1016-j.jallcom.2020.157402	-1		The elongation of high-strength copper alloy with tensile strength over 1300 MPa is generally less than 3%. In this paper, a novel Cu-20Ni-20Mn-0.3Nb-0.3Cr-0.1Zr (wt%) alloy with high strength, high elasticity and high plasticity was prepared. Its tensile strength, elastic modulus and elongation is 1445 MPa, 147 GPa and 6.8%, respectively. On the basis of Cu-20Ni-20Mn alloy, microalloying Nb, Cr, Zr elements were added to restrain discontinuous precipitation and improve the properties of the alloys. By matching reasonable heat treatment process, a fine and highly uniform grain structure was obtained, which is the main reason for the increase of elongation. TEM and 3DAP results suggested that a large number of nanoscale NiMn precipitates are the main source of high strength in the alloy. The designed alloy has excellent comprehensive properties, which can be used for the preparation of precision sensing parts, elastic components.
10.1016-j.jallcom.2020.157561	16	wear; composite; composites; powders; milling; particles; powder; wt; sliding; friction; hardness; matrix; mechanical; surface; properties	In this study copper-silver (CuAg) structures with varying Ag content were fabricated by in situ alloying and Laser Powder Bed Fusion (L-PBF) Additive Manufacturing (AM). Powder morphology, distribution and elemental analysis were conducted using Scanning Electron Microscopy (SEM) and dynamic imaging for CuAg10, CuAg20 and CuAg30 atomised powder. The resultant pore defect morphology and distribution for each as built and annealed CuAg alloy structure was investigated and reported using X-ray Computed Tomography (XCT) and 3D visualisation. The atomic crystal structure for each as built and annealed CuAg alloy is reported through X-Ray Diffraction (XRD) analysis. Yield strength, Young's Modulus, failure strain and Ultimate Tensile Strength (UTS) of as built and annealed AM CuAg structures are reported and sample fracture surfaces were analysed using SEM and Energy Dispersive X-Ray (EDX) techniques. Increased Ag content from CuAg10% to CuAg30% is shown to decrease the number of pore defects by 87% and 83% for as built and annealed samples with average pore size decreasing by 40% and 9.5%. However, the annealing process was found to increase the porosity by up to 164%. Furthermore, the annealing process resulted in atomic lattice contractions resulting in increased yield strength, Youngs Modulus and Ultimate Tensile Strength (UTS) for CuAg30%.
10.1016-j.jallcom.2020.157582	15	aging; strength; conductivity; electrical conductivity; electrical; mpa; treatment; strengthening; degrees; cu-; cold; precipitation; tensile strength; tensile; iacs	Cu-Cr and Cu-Cr-Mg alloy wires were prepared by atmospheric melt casting, hot extrusion, multi-pass drawing and heat-treatment. The effect of Mg addition on the hardness, the strength, the electrical conductivity, and the softening resistance were explored. The types and morphology of the nanoprecipitates of the two alloys were compared by transmission (TEM) and high-resolution (HREM) electron microscopy. The effect of Mg on the recrystallization of peak-aged Cu-Cr alloy was analyzed by electron back-scatter diffraction (EBSD). The results show that the addition of Mg significantly improves the strength, the hardness, and the softening resistance of aged Cu-Cr alloy. The conductivity of the aged Cu-Cr-Mg alloy can be higher than 80% IACS. The observation of the microstructure showed that the main aging strengthening phases in the two alloys was Cr nano-precipitates. The addition of Mg significantly inhibits the recrystallization process of the aged Cu-Cr alloy and the coarsening of the precipitates of the peak-aged alloy at high holding temperature. The size of precipitates and the volume fraction of recrystallization in Cu-0.4Cr alloy treated by peak aging at 500 degrees C and heat-treated at 600 degrees C for 1 h were about 5.6 nm and 25.93%, while that in Cu-0.44Cr-0.17 Mg alloy were 4.5 nm and 7.42%. The results showed that reduction of dislocation density and the coarsening of precipitate are the main reasons for the decrease in the hardness of peak-aged alloys at high holding temperature. (C) 2020 Published by Elsevier B.V.
10.1016-j.jallcom.2020.157595	-1		Cu-Cu bonding was successfully achieved through the transient liquid phase sintering (TLPS) bonding method using Cu and an eutectic Sn-Bi alloy. The bonding process was performed for total bonding process time of 2 h under a pressureless condition in air. The bonding temperature was 220 degrees C considering that the Cu6Sn5 intermetallic compound (IMC) and Bi react at 195.9 degrees C to transform into Cu3Sn and a liquid. The shear strength of Cu-70(Sn-58Bi) was approximately 22.06 MPa with the formation of the Cu3Sn. The residual eutectic Sn-Bi structure remained at Cu-90(Sn-58Bi), and the voids were largely observed at Cu-50(Sn-58Bi). In case of Cu-70(Sn-58Bi) and Cu-50(Sn-58Bi), the remelting temperature increased to 270 degrees C by the IMC reaction between Cu and Sn. On the other hand, the remelting temperature of Cu-90(Sn-58Bi) joint remained at 139 degrees C due to residual eutectic Sn-Bi structure. The salt spray test was conducted at 35 degrees C under the 5% NaCl condition for 24, 48, and 96 h to evaluate the bonding reliability under the salt spray condition. The corrosion behavior was evaluated using the electrochemical impedance spectroscopy measuring method. In addition, the thermal bonding reliability was investigated through a high-temperature storage test at 200 degrees C for 100, 500, and 1000 h . Analysis results of the experiment showed that the electrochemical and thermal bonding reliabilities were improved with the Cu3Sn formation owing to its high resistance properties under the salt spray and high-temperature conditions.
10.1016-j.jallcom.2020.157601	-1		The gamma '' phase and the gamma' phase are metastable precipitates in Cu-2.0 wt%Be alloy, which play a key role in strengthening the alloy. This paper mainly discusses the formation process, microstructure and strengthening mechanism of these two precipitates. The structure, quantity and size of precipitates in the alloy treated at different aging temperatures were analyzed by transmission electron microscopy (TEM). The strengthening mechanism of the gamma '' phase and the gamma' phase was analyzed by theoretical calculation. The results show that with the increase of aging temperature, the size of gamma '' phase changes slightly, but the density decreases significantly, while the size and density of gamma' phase increase with the increase of aging temperature. High resolution transmission electron microscopy (HRTEM) analysis shows that the gamma '' phase is semi coherent with the matrix, so it will be cut off by dislocations. The atoms in the gamma' phase are arranged perfectly, they can't shear with dislocations, so they can be strengthened by the Orowan dislocation bypass mechanism. The strength mechanism of gamma '' phase is location shear mechanism and the strengthening mechanism of gamma' phase is Orowan bypass mechanism.
10.1016-j.jallcom.2020.157677	-1		Diffusion-controlled interaction of pure Cu with Sn at 488 K results in the formation of epsilon-Cu3Sn and eta-Cu6Sn5 intermetallic compounds, and small additives of Ni in the Cu-substrate (up to 1 at. %), do not influence phase composition of the diffusion zone. It was found that in the a-phase, Sn diffuses some-what faster than Cu (and Ni) does, and diffusion porosity is developed in the vicinity of the substrate/ reaction product interface. When a Cu-Ni alloy containing (5-25) at. % of Ni is involved in the interaction at 488 K, no epsilon-phase is formed and no pores can be found in the vicinity of the reaction interface. In these couples, ThO2-partides introduced as fiducial markers at the contact surface, end up after the interaction inside the (Cu,Ni)(6)Sn-5 product layer close to the interface with Sn. The reaction layer growth follows a parabolic kinetics, and the growth rate of the (Cu,Ni)(6)Sn-5 product in the Cu1-xNix/Sn (x = 0.05-0.25) couples is much higher than that of a-phase in binary Cu/Sn and ternary couples with lower Ni-content. TEM investigation revealed that reaction product in the Cu25Ni/Sn couple consists of domains of differently oriented unit cells of long-period superlattice formed in the (Cu,Ni)(6)Sn-5 phase. In each domain, there is a periodic array of antiphase boundaries which provide a high density of short-circuit paths for diffusional transport resulting in the fast growth kinetics of the product intermetallic layer.
10.1016-j.jallcom.2020.157685	-1		The effects of rare earth element Nd on the microstructure, mechanical, shape memory properties and corrosion behaviour of Cu-13.0Al-4.0Ni-xNd (wt%) high-temperature shape memory alloys were investigated in this paper. It was observed that the grains in Cu-13.0Al-4.0Ni-xNd alloys can be refined by adding Nd, and the grain size decreased from the millimeter scale to several hundred microns. The matrix of the Cu-13.0Al-4.0Ni-xNd alloys, composed of 18R and 2H martensite, was not changed by Nd doping. However, the hexagonal (Al,Ni)Cu4Nd phase was formed as the Nd content increased. The grain refinement led to an improvement in the mechanical properties of the Cu-13.0Al-4.0Ni-xNd alloys. When x = 0.5, the compressive fracture stress and strain increased from 580 MPa to 10.5% to 940 MPa and 18.3%, respectively. The Nd addition also enhanced the shape memory effect of the Cu-13.0Al-4.0Ni-xNd alloys, and a reversible strain of 6.8% was obtained for x = 0.2 under a prestrain of 10% after heating. In addition, the results of electrochemical impedance measurement and polarization measurement showed that the corrosion resistance of Cu-Al-Ni alloy were slightly reduced by Nd addition, and the corrosion behaviour of Cu-Al-Ni alloy was mainly controlled by Cu element.
10.1016-j.jallcom.2020.157866	-1		In this work, directional solidification method was used to investigate the growth characteristics of intermetallic compounds whose solubilities are narrow during solidification of Cu-68at%Sn alloys (L + Cu3Sn -> Cu6Sn5). It is found that the transition of the leading phase occurs during solidification at the intermediate growth velocities (5, 10 and 20 mu m/s). By the application of the Interface Response Function (IRF), the calculated velocity range for the transition from the primary phase to the peritectic phase is 2.1-33.4 mu m/s. Moreover, the phase transition of intermetallic compounds Cu3Sn and Cu6Sn5 does not initiates from the initial growth interface, and the distance required for phase transition to occur is found to increase with increasing growth velocity. The measurement of the hardness and Young's modulus was accomplished by the continuous stiffness measurement (CSM) technique during nanoindentation. The elastic modulus is nearly constant while the hardness increases with increasing growth velocity. In summary, the hardness of Cu3Sn phase is lower than that of Cu6Sn5 phase but Young's modulus shows reverse trend. In addition, multiple pop-in events are observed on the load-displacement curves of Cu6Sn5 phase at a strain rate of 0.1s(-1).
10.1016-j.jallcom.2020.158142	6	grain; deformation; strain; strength; dislocation; cu-; tensile; size; ecap; grain size; sfe; ductility; hardening; high; stress	Experiments were conducted to evaluate the evolution of the stored energy in grains with shear texture orientations A(1)* {111} <<(1)over bar>(1) over bar2 >, A(2)*{111} < 1<(2)over bar>1 >,A {111} < 1<(1)over bar>0 >, (A) over bar {111} < 0<(1)over bar>1 >, B {112} < 1<(1)over bar>0 >, (B) over bar {112} <1<(1)over bar>0> and C {100} < 110 > for Cu 2.5Ni 0.6Si and Fe-36Ni (wt%) alloys after high-pressure torsion (HPT) processing up to 10 turns at ambient temperature using a Kernel Average Misorientation (KAM) approach . A typical stable shear texture developed in the Cu-2.5Ni-0.6Si alloy immediately after 1 turn whereas there was a continuous transformation of texture in the Fe-36Ni alloy up to 10 turns. The results show that HPT processing produces similar stored energies of similar to 35 J/mol and similar to 24 J/mol but with different shear texture components for the Cu-2.5-Ni-0.6Si and the Fe-36Ni alloy, respectively. The stored energy in all shear components for the Cu-2.5Ni-0.6Si alloy increases with increasing HPT processing up to 1 turn and then slightly decreases through 10 turns. By contrast, the stored energy of the Fe-36Ni alloy continuously decreases with increasing numbers of HPT turns. These evolutions are examined with reference to the initial textures, dynamic recrystallization, grain refinement mechanisms and differences in the stacking fault energies.
10.1016-j.jallcom.2020.158531	-1		The average energy per atom, the formation energies, and the cohesive energies of Cu-Cr-X (X=Zr, Ag, and In) phases with body-centered cubic (BCC) or face-centered cubic (FCC) structures were calculated using the first-principles method. The phase transformation sequence in the Cu-Cr binary alloy and the distributions of Zr, Ag, and In atoms in CuCrX precipitates were also studied. FCC atomic clusters are formed in the Cu-Cr binary alloy at the beginning of aging, and then transformed into a metastable FCC Cu-Cr phase during aging. When the Cr concentration of the precipitates increases to 60 at%, the formation and cohesive energies of the BCC Cu-Cr phase become less than those of the FCC Cu-Cr phase. This indicates that the BCC Cu-Cr phase is more stable than the FCC structure. In Cu-Cr-X (X=Zr, Ag and In) ternary alloys, Zr atoms are mainly distributed in the periphery of FCC CuCrZr precipitates, while Ag atoms are randomly distributed in FCC CuCrAg precipitates, which is consistent with experimental results. High-resolution transmission electron microscopy and atom probe tomography indicate that In atoms are randomly distributed in the CuCrIn precipitates of the under-aged Cu-Cr-In alloy. This is consistent with our first-principles calculations.
10.1016-j.jallcom.2021.158667	-1		The effects of Co on the physical properties and precipitation evolution of a Cu-Ni-Si alloy are investigated via hardness and electrical conductivity testing, transmission electron microscopy and a quantitative three-dimensional atom probe. The precipitation sequence of Cu-Ni-Si alloy aging at 500 degrees C can be expressed as supersaturated solid solution -> solute clusters -> GP zones -> Ni2Si phases. In the early aging stage, the formation of atomic clusters is accompanied by the occurrence of spinodal decomposition. The addition of Co accelerates the redistribution and agglomeration of solute atoms, resulting in the nucleation of (Ni, Co)(2)Si phases directly from the supersaturated state, which further hinders atomic cluster formation and spinodal decomposition. The Ni2Si and (Ni, Co)(2)Si phases, which are divided into a region II containing pure Ni2Si and the (Ni, Co)(2)Si phase and an unstable region I containing a small amount of Cu atoms, show the same crystal structure and orientation relationship with the matrix. During the aging process, the range of region I is gradually replaced by the core stable region II and accompanied by the growth of the total thickness of the precipitated phase. This remarkable age effect with Co addition can be attributed to the enhanced number of (Ni, Co)(2)Si precipitates, which simultaneously increases the strength and electrical conductivity.
10.1016-j.jallcom.2021.158687	-1		Fine dispersion of nanoscale particles in particle-dispersion-strengthened metallic materials is crucial for good mechanical and physical properties of the materials. In this study, the introduction of a small amount of Ti (0.2 wt%) into a mechanically alloyed Cu-2.03 wt% Al2O3 alloy powder is observed to improve the dispersion of Al2O3 nanoparticles with an initial average size of similar to 50 nm and influence the Cu matrix microstructural features in bulk samples extruded from mechanically alloyed and annealed Cu-Al2O3 alloy powder compacts. Atom probe tomography (APT) analysis reveals that the Ti dopant simultaneously dissolves into the Al2O3 nanoparticles and segregates at the Cu/Al2O3 interfaces. Tensile results manifest that noticeably different tensile ductilities are derived for the extruded samples with ((9.3 +/- 1.2)%) and without ((5.7 +/- 0.5)%) Ti addition. This clear difference in ductility may be attributed to the relatively large ultrafine Al2O3 particles and the Ti-decorated Cu/Al2O3 interfaces. The experimental evidence is discussed here based on the effects of trace Ti alloying element on the stabilization of the Al2O3 nanoparticles, Cu matrix microstructural evolution and tensile properties.
10.1016-j.jallcom.2021.158863	6	grain; deformation; strain; strength; dislocation; cu-; tensile; size; ecap; grain size; sfe; ductility; hardening; high; stress	The deformation mechanism and mechanical properties of pure copper and copper-zinc alloys with low stacking fault energy (SFE) were investigated primarily. In this paper, pure Cu and Cu-30%Zn samples were processed by surface mechanical attrition treatment (SMAT) at cryogenic temperature. The results show that Cu-30%Zn samples exhibit higher yield strength and better ductility by tensile tests at room temperature. With the same processing time of SMAT, the SMAT-ed Cu-30%Zn samples exhibit an optimized combination of strength and ductility compared with that of the SMAT-ed Cu samples. The in-situ electron backscatter diffraction (EBSD) tests show that there is a high density of geometrically necessary dislocations (GNDs) in SMAT-ed Cu-30%Zn samples with low SFE, thereby forming a strong hetero-deformation induced (HDI) stress strengthening and HDI hardening. Also, the twins promote the accumulation of geometrically necessary dislocations to enhance strength while maintaining good ductility in the Cu-30%Zn samples.
10.1016-j.jallcom.2021.158973	-1		In this research, the structure, tensile, wear, fracture toughness, and corrosion characteristics of Cu/Zn/Al multilayered composites fabricated by cross accumulative roll bonding (CARB) were determined. X-ray diffraction and scanning electron microscopy were used for structural analyses. Results showed that the crystallite size of the Cu matrix is reduced to about 50 nm at the ninth cycle of CARB, while the plastic instability and shear bands appeared in the layers after the third cycle. The tensile strength of the composites increased up to the third CARB cycle and then decreased to the ninth CARB cycle gradually. Typically, the maximum strength of about 330 MPa and elongation of almost 31.5% were obtained at the third and first cycles, respectively. A similar trend was found for the fracture toughness of the samples, so that the maximum fracture toughness of about 31 MPa.m(1/2) was obtained at the third cycle. It was also shown that the wear mechanism of the composite samples changes by increasing the cycles, a compromise of abrasion and delamination wear. The accommodation of Al and Zn layers toward the surface of the composites by increasing the CARB cycles was also recognized to be responsible for the decrease of the corrosion resistance determined by polarization experiments.
10.1016-j.jallcom.2021.159031	-1		The intermetallic Cu6Sn5 is ubiquitous in electronic interconnects where research has focused on controlling the size and distribution of this phase for improved performance. Cu6Sn5 also finds application as an anode material for advanced lithium-ion batteries. Cu6Sn5 anodes can be fabricated via an in-situ growth method involving the reaction between molten Sn and the Cu current collector. This manufacturing route offers some advantages over traditional anode fabrication however the process is slow, limiting its practical application. In this work we show the addition of 6 wt% Ni to the Cu current collector greatly accelerates the growth of (Cu,Ni)(6)Sn-5 in Cu-xNi/Sn solid-melt couples, leading to a growth rate of up to 50x faster, reducing the processing time above 200 degrees C to less than 10 min. This research studies the dynamics of the formation of (Cu,Ni)(6)Sn-5 between Cu-xNi alloys and liquid Sn through real-time observation using synchrotron X-ray imaging. The (Cu,Ni)(6)Sn-5 growth dynamics are characterised, and the growth kinetics are analysed. Subsequently, the mechanism of the accelerated growth is investigated with electron backscatter diffraction and transmission electron microscopy. The results show the accelerated growth is due to the formation of eta-(Cu,Ni)(6)Sn-5 grains with two distinct Ni concentration ranges, leading to finer grains and spalling, which in turn facilitates the diffusion of Sn, enhancing the eta-(Cu,Ni)(6)Sn-5 formation kinetics.
10.1016-j.jallcom.2021.159632	10	composites; nanoparticles; strength; matrix; high; strengthening; particles; conductivity; composite; electrical; mpa; sintering; ods; grains; mechanical	In this work, the copper (Cu) matrix composites reinforced by medium entropy alloy (MEA) CrCoNi particles with microlaminated structure were successfully fabricated using vacuum filtration, spark plasma sintering (SPS) and subsequent hot rolling. The effects of the content of MEA CrCoNi particles on the mechanical properties were systemically investigated, and the relevant strengthening and toughening mechanism were discussed. It is found that the fabricated composites present much higher strength than their counterpart of pure Cu. Moreover, the combination of high strength (326 +/- 3.9 MPa) and good ductility (20.9 +/- 2.3%) with using 10 vol% CrCoNi particles as reinforcement can be achieved, which can be attributed to the combined effects of uniform dispersion of CrCoNi particles, well bonded interface bonding, the microlaminated structure. It is determined that the load transfer strengthening is the dominant strengthening mechanism in present fabricated composites. This work sheds light on fabricating Cu matrix composites with high mechanical properties by employing novel reinforcement and microstructure design.
10.1016-j.jallcom.2021.159933	-1		Cu-Co alloy is an intermediate product from the pyrometallurgical processing of cobalt oxide ores, which mainly contains metallic components of Cu, Co, Fe and Si. This research aims to extract Cu from Cu-Co alloy by selective dissolution using molten Mg. The alloy particles were mixed with Mg and held at temperatures in the range 700-900 degrees C for 0.5-2 h . The residual Fe-Co-Si alloy settled to the bottom of the melt due to the density difference between the alloy and molten Mg. Under optimal conditions, as much as 99 wt% Cu can be selectively extracted from the alloy by dissolution into the molten Mg. Vacuum distillation at 900 degrees C was applied to the obtained Mg-Cu alloy, resulting in the formation of Cu power with 80 wt% purity. The recovered Mg metal after distillation could potentially be recycled for re-use. Therefore, this process achieved efficient extraction of Cu without the consumption of Mg and generation of waste, representing an effective and environmentally-sound approach for the processing of Cu-Co alloy.
10.1016-j.jallcom.2021.159985	-1		The phase components, microstructures, and compressive properties of a novel 3d transition metal high entropy alloy, CuFeNiTiV, in the as-cast condition were investigated. Thermodynamic simulations showed that the phases separation during solidification occurred in the order: (V, Fe) dendrites, Cu-rich phase, TiFeNi-like laves phase and (Ni, Ti)-rich phase. The simulation results were confirmed by determining the as-cast alloy's phase components using XRD, which mainly consisted of BCC and FCC phases. The BCC phase corresponded to (V, Fe)-rich dendrites, while the FCC phase contained a Ni(Ti, Fe)-like C15 Laves phase, a Cu-rich phase, and a (Ni, Ti)-rich FCC phase. An outstanding fracture strength of 2086 MPa was obtained in the as-cast alloy, which was attributed to the deformation resistance of both the major BCC phase and laves phase.
10.1016-j.jallcom.2021.160050	-1		This study investigated ways to improve both the mechanical and thermal properties of a Cu-Ni-Sn-P alloy manufactured with selective laser melting (SLM) using aging treatment. Homogenization heat treatment was conducted to the alloy at 820 degrees C for 12 h, and aging heat treatment was applied at 400 degrees C for 0.25, 0.5,1, 2 and 4 h . Initial microstructure analysis identified (Cu, Ni)(3)P phase precipitates of a few mu m in size, and the size and fraction of precipitates increased as aging heat treatment time increased. Room temperature compressive tests on the homogenized sample identified a yield strength of 135.7 MPa. Meanwhile, the yield strength of the sample that underwent 2-hour aging treatment measured 454.5 MPa, indicating a three times greater improvement of the mechanical properties than the homogenized sample. This was confirmed to have been contributed by precipitation hardening from the increased precipitate size and fraction as a result of aging treatment. In addition, thermal conductivity also increased as aging treatment was performed. In particular, an aging time greater than 2 h achieved an approximately 30% increase in thermal conductivity compared to the homogenized sample. Through aging treatment, both the mechanical property and thermal conductivity of an SLM-built Cu-Ni-Sn-P alloy were improved. Based on these findings, this study also discussed the underlying mechanisms according to aging time with respect to microstructural changes.
10.1016-j.jallcom.2021.160213	-1		The use of carbon/copper (C/Cu) composites as electrical contact materials has developed rapidly owing to their superior mechanical strength, electrical conductivity, and self-lubricity. However, the non-wettability of carbon and copper restricts further improvement in their performance. In this work, a strategy based on copper-boron alloying is proposed, to improve C/Cu interfacial bonding, and Cu-B/sintered-carbon com-posites were successfully prepared using a gas pressure impregnation technique. The results show that the compressive and flexural strengths of the modified composites increased by 39% and 54%, respectively, and the C/Cu contact angle decreased from 123.6 degrees to 21.3 degrees in the case of 2.5 wt% B doping. A minimum electrical resistivity of 1.7 mu O center dot m was achieved when a moderate boron content (1.2 wt%) was selected. The role of boron carbide was examined, and competitive mechanisms of C/Cu interfacial bonding level and electrical conductivity are proposed, based on aspects of interfacial resistance and scattering of conducting electrons.
10.1016-j.jallcom.2021.160475	-1		Cu-Cr alloy is a kind of functional and structural integrated material with excellent comprehensive mechanical and electrical properties. However, due to the low solubility of Cr in Cu and the huge difference in melting point, the existing methods to manufacture well-structured Cu-Cr alloys are facing many challenges. In this paper, laser additive manufacturing (LAM) is applied to manufacture CuCr30 with ideal structure, taking advantage of its characteristics such as the small molten pool and fast crystallization. A small amount of microporosity defects formed during the LAM process were then reduced by severe shear deformation in the subsequent continuous extrusion process. As a result, the strength of the CuCr30 was increased by 55.3% and the room temperature conductivity was increased by 6.6%. Although the Cu grain refinement leads to fine grain strengthening and the homogenization of Cr distribution leads to enhancement of second phase strengthening during continuous extrusion, both have a negative effect on conductivity, the room temperature conductivity of CuCr30 did not decrease, because of the reduction of pore defects and the formation of nano-twinned structure with thickness of 10-30 nm, which improves the strength without affecting the conductivity.
10.1016-j.jallcom.2021.160580	-1		Lead-free FeS/Cu-Bi (FCB) copper matrix composites were prepared by ball milling and in situ Ni-coated FeS surface modification, and their mechanical and tribological properties were studied. Results showed that the hardness of the prepared FCB material increases from 50.5 HRB to 64 HRB, and its density also increases from 5.82 g/cm(3) to 6.96 g/cm(3). Although FeS surface modification can improve the mechanical properties of the prepared materials, their impact toughness and crushing strength decrease after the mechanical al-loying of the mixed powders. However, these two processes have a good synergistic effect on improving the tribological properties of the prepared materials. The friction coefficient and wear rate of the prepared FCB composites were reduced by 29% and 73.2%, respectively. The surface modification and uniform dispersion of the second phase particles in the matrix led to enhancement in the binding energy with the matrix and the mechanical and tribological properties of the materials.
10.1016-j.jallcom.2021.160604	0	solidification; phase; magnetic; magnetic field; undercooling; field; liquid; separation; peritectic; immiscible; cu-; dendrite; phase separation; microstructure; primary	An intensive field of 20 kHz power ultrasound with various amplitudes was applied during the solidification process of quaternary Cu-7%Al-4%Ni-2.5%Mn single-phase alloy to investigate its dynamic solidification mechanism and mechanical performance improvement. It is found that a(Cu) phase nucleates at small undercoolings and mainly grows along (111) crystalline plane direction into coarse dendrites with devel-oped secondary arms. With the rise of amplitude, ultrasonic wave increases the nucleation rate by improving the wetting effect between alloy melt and impurities and also breaks some growing dendrites into fragments. Once the ultrasonic amplitude reaches the maximum of 15.2 mu m, the prominent cavitation effect further increases the nucleation rate by three orders of magnitude, and also leads to the symmetrical distribution of temperature field, solute field and flow field in the solidification front, eventually resulting in the formation of tiny equiaxed a(Cu) grains without any obvious preferred growth orientation, inside which the solute distribution also tends to become uniform. Meanwhile, the compressive yield strength of Cu7%Al-4%Ni-2.5%Mn alloy is significantly increased by 3 times after ultrasonic solidification. Theoretical analysis indicates that grain strengthening and dislocation strengthening are the two main reinforcement factors induced by power ultrasound.
10.1016-j.jallcom.2021.160769	15	aging; strength; conductivity; electrical conductivity; electrical; mpa; treatment; strengthening; degrees; cu-; cold; precipitation; tensile strength; tensile; iacs	A Phi 40 mu m Cu-4 wt%Ag alloy wire with high strength and high electrical conductivity was prepared by continuously directional solidification and cold drawing. The evolution of microstructure and properties was investigated by means of optical microscope observation, electron microscopes observation, hardness test, tensile test, and electrical conductivity measurement. The continuous columnar-grain structure uniformly distributed along the solidification direction in the as-cast alloy. The drawing process was divided into three stages: general deformation stage, large deformation stage and extreme deformation stage. The main deformation mechanisms of the alloy in each stage are corresponding to the dislocation slip and twinning, the dynamic recovery, the evolution of layered interface, and partial dynamic recrystallization. After the deformation with the drawing strain of 11.28, the tensile strength, yield strength, and electrical conductivity of the alloys were 1048 MPa, 886 MPa, and 75.2%IACS, respectively. The main strengthening mechanism of the alloys was grain refinement strengthening according to the calculation results of the strengthening model.
10.1016-j.jallcom.2021.160783	-1		With the trend of increasing product miniaturisation, it has become necessary to consider the service performances of microparts. If the material exhibits the 'smaller is stronger' geometry size effect (GSE), the mechanical properties data of conventional dimension specimens can be used to design the micro parts, obtaining improved service safety of the microparts. The surface layer model shows that when the exterior mechanical properties of material are higher than these of the interior, the 'smaller is stronger' GSE can be obtained. Stacking fault energy (SFE) and reduction ratio (RR) have been reported to affect the distribution of mechanical properties along the thickness direction of a rolled material, so that they are expected to affect the GSE of rolled sheets. Therefore, the tensile mechanical properties of different SFE Cu-Al alloys cold rolled at different RR were examined in this work. The average grain size of the surface layer of the rolled specimens was smaller than that of the interior, whereas the average strain and microhardness of the surface layer were larger than those of the interior. The difference in the strain between the exterior and interior of the specimen was found to decrease with the specimen thickness t, and increases with RR and SFE. The 'smaller is stronger' GSE trend was found in pure Cu and CuAl alloy rolled at 30 -50% RR, while GSE changed to 'smaller is weaker' at RR = 70%. The magnitude of the GSE of the rolled specimens increased with increasing RR and SFE, resulting from the effects of RR and SFE on the microstructure, microhardness and strain distribution. New models for the relationship between the strengths and t and SFE were established for three RRs. The results predicted by the models were in good agreement with the experimental values.
10.1016-j.jallcom.2021.160823	-1		Cu-50 at% Co and Cu-68.5 at% Co metastable monotectic Cu-Co alloys have been rapidly solidified in a 6.5 m drop tube facility under nitrogen atmosphere. Microstructural evidences proved that liquid phase separa-tion occurred in the alloys as predicted by the phase diagram of the alloy system. As well as liquid phase separated structures, substantial amount of dendrites were also observed. The resulting undercooled metal powders were sieved into ten size fraction range and the SDAS measurements taken using SEM images. Owing to the large number of liquid phase separated structures in the Cu-50 at% Co alloy, SDAS measurements were taken from six size fractions while in the Cu-68.5 at% Co alloy measurements were limited to three size range due to the fragmented nature of its dendrites as the droplet size fraction reduced. A regression relationship between cooling rate and the experimental SDAS measurements was established and an expression of the type lambda(SDAS) = Lambda((T) over dot)(-n) was observed in both of the alloys in which the exponential value (n) is approximately 0.2.
10.1016-j.jallcom.2021.160865	3	sma; shape; shape memory; memory; smas; superelastic; bars; damping; cu-al-mn; mechanical; bending; applications; numerical; sma bars; material	Superelasticity is a characteristic thermomechanical property in shape memory alloys (SMA), which is due to a reversible stress-induced martensitic transformation. Nano-compression experiments made possible the study of this property in Cu-Al-Ni SMA micropillars, showing an outstanding ultra-high mechanical damping capacity reproducible for thousands of cycles and reliable over the years. This scenario motivated the present work, where a comparative study of the damping capacity on four copper-based SMA: Cu-Al-Ni, Cu-Al-Be, Cu-Al-Ni-Be and Cu-Al-Ni-Ga is approached. For this purpose, [001] oriented single crystal micropillars of comparable dimensions (around 1 mu m in diameter) were milled by focused ion beam technique. All micropillars were cycled up to two hundred superelastic cycles, exhibiting a remarkable reproducibility. The damping capacity was evaluated through the dimensionless loss factor eta, calculated for each superelastic cycle, representing the dissipated energy per cycle and unit of volume. The calculated loss factor was averaged between three micro-pillars of each alloy, obtaining the following results: Cu-Al-Ni eta = 0.20 +/- 0.01; Cu-Al-Be eta = 0.100 +/- 0.006; Cu-Al-Ni-Be eta = 0.072 +/- 0.004 and Cu-Al-Ni-Ga eta = 0.042 +/- 0.002. These four alloys exhibit an intrinsic superelastic damping capacity and offer a wide loss factor band, which constitutes a reference for engineering, since this kind of micro/nano structures can potentially be integrated not only as sensors and actuators but also as dampers in the design of MEMS to improve their reliability. In addition, the study of the dependence of the superelastic loss factor on the diameter of the pillar was approached in the Cu-Al-Ni-Ga alloy, and here we demonstrate that there is a size effect on damping at the nanoscale. (c) 2021 The Author(s). Published by Elsevier B.V. CC_BY_NC_ND_4.0
10.1016-j.jallcom.2021.160912	-1		A new Cu-2Ag-0.14La alloy is developed to enhance the mechanical property and electrical conductivity with inducement of Ag-rich primary phases and finer nanoscale Ag precipitates. The microstructural evolution and mechanical properties of Cu-2Ag-0.14La and Cu-2Ag alloys obtained by drawing and annealing were then summarized and analyzed. The results indicate that both the yielding and ultimate tensile strengths of annealed Cu-2Ag-0.14La alloy were reinforced after La modification. The average grain sizes of two alloys increase during annealing, but the size ratio (RCu-2Ag-0.14La/RCu-2Ag) dramatically varies with rising the heat temperature, evolving from 70.48% at 400 degrees C to 43.78% at 650 degrees C. Meanwhile, it is found that the refined grains sizes in Cu-2Ag-0.14La alloy are closely related to the nano-scale precipitates (similar to 450 nm), which hinder the formation of subgrain boundaries at 400 degrees C, and impose a stronger pinning effect on boundary migration of recrystallized grains during annealing (>= 450 degrees C). Consequently, higher hardness and electrical conductivity are contributed by grain refinement and dispersion strengthening of the nanosized phases.
10.1016-j.jallcom.2021.161220	-1		Although chemical structural heterogeneities were induced into metallic glasses (MGs) to improve their ductility, the nature of the influence of the heterogeneous structure on their deformation behavior is still unclear. Here, by using microalloying elements to tailor the microstructure in Cu-Fe-Zr MGs, the formation of heterogeneous structure and the correlation between the heterogeneous structure and the deformation behavior are discussed. The results show that a honeycomb-like heterogeneous structure is formed in the (Cu0.5Fe0.5)(40)Zr59X1 (X=Nb and Ta) alloys. From a viewpoint of dynamic, the nature of the microalloying effect on the microstructure has been analysed. The deformation behavior of (Cu0.5Fe0.5)(40)Zr59X1 MGs with a high population of nanoscale glassy particles (NGPs) is investigated by nanoindentation and bending test. These glassy particles play an interesting role in the internal record of the local structure evolution. It was found that NGPs contiguous to shear bands (SBs) coarsen by Ostwald ripening. However, NGPs within SB would dissolve due to direct mechanical shearing and mixing. It indicates that the volume of shear transformation zone decreases obviously in the heterogeneous MGs due to the high fraction of interfaces. This work is of significance in understanding the relationship between structure and property of MGs.
10.1016-j.jallcom.2021.161267	-1		Cu-As alloy is viewed as one kind of secondary copper resources. It is difficult to simultaneously recover copper and remove arsenic using conventional processes. To separate arsenic and tin from Cu-As alloy (mainly Cu3As), an innovative methodology that uses vacuum distillation in the presence of pyrite to form new phase is proposed herein. The constituents, phases and morphology of the sample before and after vacuum distillation were investigated by chemical analysis, X-ray diffraction (XRD) analysis and electron probe microanalysis (EPMA) to interpret separation performances and volatilization mechanisms of arsenic and tin. Chemical analysis results showed that it is difficult to separate arsenic from Cu-As alloy by direct vacuum distillation, but arsenic and tin were effectively separated after introducing pyrite. The effects of several factors, such as temperature, pyrite dosage and distillation time, on separation performances of arsenic and tin were examined. Volatilization ratios of copper, arsenic and tin reached 0.84%, 96.29% and 88.70%, respectively. Results of XRD analysis and EPMA revealed that arsenic had strong affinity to copper in Cu-As alloy, which inhibited free volatilization of arsenic. After introduction of pyrite, formation of copper sulfides, such as mainly Cu5.433Fe1.087S4, Cu1.96S and Cu9S5, destroyed the alloy structure, which made elemental arsenic volatilize. Excessive sulfur also interacted with elemental arsenic to form mainly As4S3 that is also easily volatilized. Nevertheless, tin was only separated in the form of SnS. It is a promising method to achieve cleaner utilization of Cu-As alloy and effective control of arsenic pollution.
10.1016-j.jallcom.2021.161321	-1		This study aims to enhance the dimensional stability of alumina dispersion strength copper alloy via creep annealing treatment. The microstructure, residual stress and micro-yield strength of alloys after different treatments were investigated. During creep annealing, the residual stress in the alloy was dramatically reduced due to the decrease of dislocation density. The nano-Al2O3 particles in the alloy did not coarsen or agglomerate during the high temperature treatment and retarded the growth of subgrains effectively, which played important roles in high micro-yield strength of creep annealed alloy. The pores were effectively reduced by the creep deformation during creep annealing, resulting in a more uniform residual stress distribution and an increase in micro-yield strength . Compared with extruded alloy, the residual stress of alloy creep annealed at 950 degrees C for 12 h was reduced by 88%, while the micro-yield strength increased by 9.7%, leading to a significant enhancement in dimensional stability of the alloy. (c) 2021 Published by Elsevier B.V.
10.1016-j.jallcom.2021.161458	15	aging; strength; conductivity; electrical conductivity; electrical; mpa; treatment; strengthening; degrees; cu-; cold; precipitation; tensile strength; tensile; iacs	Cu-6.5Fe-0.2Cr (CFC) and Cu-6.5Fe-0.2Cr-1Ag (CFCA) alloys were prepared by upward continuous casting to investigate the influence of Ag on the microstructure, mechanical properties and electrical properties of CFC alloy. The properties testing discovered that the mechanical properties and electrical conductivity of CFC alloy were improved by the addition of Ag. The peak strength of CFCA alloy (622 MPa) was 33 MPa higher than that of CFC alloy, and the peak conductivity (67.8% IACS) was increased by 5% IACS after aging. The microstructure observation showed that Cr element was mainly distributed in the primary Fe phase. The addition of Ag refined and promoted the precipitation of nano-scale Fe phase, and improved the coordinated deformation ability of Cu/Fe, resulting in excellent comprehensive performance of CFCA alloy. In addition, the effect of Ag on nano-scale Fe phase precipitation kinetics was explored by the modified Johnson-Mehl-Avrami-Kolmogorov (JMAK). The addition of Ag reduced the activation energy of the Fe phase and promoted the precipitation kinetics of the Fe phase. And the activation energy of CFC and CFCA alloys was 66.1 and 63 kJ/mol, respectively.
10.1016-j.jallcom.2021.161627	0	solidification; phase; magnetic; magnetic field; undercooling; field; liquid; separation; peritectic; immiscible; cu-; dendrite; phase separation; microstructure; primary	In the present study, metastable immiscible Cu-20Fe-xB alloys with different B addition content were systematically investigated. Experimental results demonstrated that the introduction of micro-alloying B element results in significant change in the solidification microstructure. It was found the volume fraction of phase-separated Fe-rich spherulite increases with increasing B addition content accompanied with an increase in the average size, which experimentally confirms that the liquid-liquid phase separation is further enhanced as B addition increases. In addition, statistical result on scaled size distribution of the phase-separated Fe-rich spherulite indicated that both the concentrated location for the first and second peak are shifted to a larger size scale with increasing B addition. Phase diagram calculation confirms that a stable miscibility gap comes into being by introducing B element, and the length of miscibility gap for Cu20Fe alloy is obviously enlarged with increasing B addition amount. This should be responsible for such above-mentioned experimental results. Besides, the magnetic properties of Cu-20Fe alloy can be obviously enhanced with B addition. For Cu-20Fe-0.3B alloy, the saturated magnetization is 41.74 emu/g, which is 32.3% significantly higher than that of the original Cu-20Fe alloy (31.56 emu/g). It is anticipated that the present study provides a feasible method by tailoring the micro-alloying B content for immiscible Cu-Fe alloy thus offering desired magnetic properties.
10.1016-j.jallcom.2021.161700	15	aging; strength; conductivity; electrical conductivity; electrical; mpa; treatment; strengthening; degrees; cu-; cold; precipitation; tensile strength; tensile; iacs	In this paper, the microstructure and properties of the upward continuous casted Cu-Cr-Zr alloy during thermo-mechanical treatment are investigated. Columnar crystal structure was formed in the alloys along the upward direction by controlling the traction speed and cooling rate. Due to the genetic characteristics of the columnar crystal structure during the thermo-mechanical treatment, the microstructure of the alloys was optimized, and the grains were obviously refined after cold drawing. The results show that a large amount of columnar crystal structure can be obtained when the traction speed was 4 mm/s and the mechanical properties of the alloy were significantly improved by the columnar crystal structure and the increase of Zr content. The alloy with columnar crystal structure and higher Zr content possesses higher tensile properties, while the electrical conductivity remained relatively stable. The ultimate tensile strength (UTS) of the Cu-0.62Cr-0.34Zr alloy was 587.8 MPa after 80% cold drawing, which is significantly higher than that of the Cu-0.56Cr-0.07Zr alloy (517.7 MPa). Additionally, the grain refinement mechanism and strengthening mechanism are discussed and concluded.
10.1016-j.jallcom.2021.161835	6	grain; deformation; strain; strength; dislocation; cu-; tensile; size; ecap; grain size; sfe; ductility; hardening; high; stress	Gradient structured (GS) materials have been reported to exhibit an outstanding mechanical properties. However, the influence of processing parameters on the GS specimens with different stacking fault energies (SFEs) and microstructural evolution during tensile are not very clear. In the present work, GS Cu-Al alloys with different SFEs of 28, 12 and 6 mJ/m(2) were prepared by surface mechanical attrition treatment (SMAT) for different processing times. Results revealed that the SFE of 6 mJ/m(2) specimen for SMAT 15 min exhibited a superior combination of strength and ductility, which had a significant hetero-deformation induced (HDI) stress originating from the accumulation of geometrically necessary dislocations (GNDs). Microstructure observations showed that deformation twins in the SFE of 6 mJ/m(2) specimens formed in the gradient layer owing to its lower SFE. Moreover, in-situ electron backscatter diffraction (EBSD) revealed that the GNDs of the SFE of 6 mJ/m(2) specimen initially formed at the grain boundaries with gradient grain size. Then, the formation of GNDs gradually migrated to the coarse grain region with increasing strain, which resulted in the HDI strain hardening and HDI stress strengthening. This work provide strategies to optimize properties and an understanding of deformation mechanisms in the GS materials during tensile test.
10.1016-j.jallcom.2021.161938	4	transformation; martensite; martensitic; phase; shape; beta; memory; shape memory; temperature; temperatures; martensitic transformation; gamma; transformation temperatures; effect; thermal	The evolution of the structure, electrical resistivity and microhardness of the non-stoichiometric Cu-56Au (at%) alloy during the disorder <-> order phase transitions of samples with different thermo-mechanical histories has been studied. It was found that the rate of atomic ordering of the Cu-56Au alloy was much lower compared to the equiatomic Cu-50Au alloy that had been well studied earlier. It was shown that the deformation of the quenched alloy slowed down the rate of atomic ordering. It was established that annealing of the quenched alloy for 1 week at 250 degrees C led to the formation of the CuAuI phase with a degree of long-range atomic order S approximate to 0.8. The electrical resistivity of the alloy in this state is rho = (7.75 +/- 0.04) x 10 = (7.75 +/- 0.04) x 10(-8) Omega m, which is the lowest value known for this alloy. It was revealed that the ordered CuAuII phase forms as a result of annealing of the Cu-56Au alloy at high temperature followed by slow cooling to room temperature. During the experiments, we did not receive any data confirming the CuAuII -> CuAuI transition both at heating and at cooling of the alloy. There was made a conclusion of a high thermal stability of the ordered orthorhombic CuAuII phase in the alloy under investigation.
10.1016-j.jallcom.2021.162035	-1		Cu1.8S (digenite), a copper sulfide with natural Cu deficiencies, possesses excellent conductivity, low-cost, as well as environmentally friendly features. It has thus recently attracted heightened attention. However, the thermoelectric performance of pristine Cu1.8S is poor, and the related mechanical properties have not been deeply investigated, which hinders this material from becoming a candidate for commercial applications. This work proposes an effective approach to synergistically improve the comprehensive performance of polycrystalline Cu1.8S-based bulk materials for use in practical applications. Cu1.8S-xRu (x = 0.005, 0.01, 0.02) bulk composites were successfully fabricated by combining mechanical alloying and spark plasma sintering technology. Benefiting from the overall optimized power factor and thermal conductivity by the regulated carrier concentration and enhanced phonon scattering effect from the incorporation of multiscale lattice defects, a peak figure of merit of 1.0 at 773 K was achieved in the Cu1.8S-1% Ru bulk specimen. In addition, the introduction of ruthenium could enhance the thermal stability of Cu1.8S materials by suppress the Cu ions motion. A conversion efficiency of 1.0% at a temperature difference of 480 K was obtained for the single-leg TE module. Finally, the excellent average Vickers hardness of 1.22 GPa for the Cu1.8S-1%Ru bulk composite was higher than that of other state-of-art TE materials. Compositing with ruthenium might be an approach worth promoting to synergistically improve the thermoelectric and mechanical performance of other materials.
10.1016-j.jallcom.2021.162233	-1		Copper matrix composites reinforced with graphene nanoplatelets (GNPs) were fabricated using an electroless plating method, and the effects of the GNP content on the thermal conductivity (TC), coefficient of thermal expansion (CTE), and mechanical properties of the composites were studied. The TC, CTE, and strength of the composites were measured in the in-plane and through-plane directions and compared. Increasing the GNP content in the GNP/Cu composite was effective in reducing the CTE and increasing the compressive yield strength of the composite. The compressive yield strength was higher in the through plane direction, but the maximum compressive strength was higher in the in-plane direction. In the case of compressive deformation in the in-plane direction, a single shear fracture with one fracture direction occurred. The compressive deformation in the through-plane direction of the composite with high GNP content (15% and 20%) exhibited a duplex shear fracture with two fracture directions. The significant findings of the present study are that it is possible to fabricate GNP/Cu composites with uniformly dispersed GNPs and low porosity by electroless plating. In addition, the failure mechanism of GNP/Cu composites was revealed for the first time.
10.1016-j.jallcom.2021.162302	15	aging; strength; conductivity; electrical conductivity; electrical; mpa; treatment; strengthening; degrees; cu-; cold; precipitation; tensile strength; tensile; iacs	C70250 (Cu-2.6 wt%Ni-0.5 wt%Si) alloy plates with straight columnar grains, inclined columnar grains and equiaxed grains were produced by a heating-cooling combined mold (HCCM) horizontal continuous casting, respectively, and the influences of microstructure on the mechanical properties of the alloy were studied. The results showed that, when the casting speed was 30 mm/min, the straight columnar grains along the casting direction formed in the C70250 alloy plate and the precipitate content was relatively high, similar to 10%. When the casting speed was 50 mm/min and 80 mm/min, inclined columnar grains and equiaxed grains formed, respectively, with a low precipitate content of 6%. The high casting speed made the solid-liquid interface at the entrance of the cold mold and the solidified plate was cooled rapidly due to strong cooling effect, which suppressed formation of precipitated phase. The yield strength of the alloy plate with equiaxed grains were 219 MPa and the elongation to failure was 36%. For the plate with inclined columnar grains, its yield strength (76 MPa) were obviously lower than that of the other two plates and the elongation reached 45%. Compared with the equiaxed grain plate, the columnar grain plate had smaller grain orientation difference, better intergranular deformation compatibility and intergranular deformation uniformity, which was mainly responsible for its better plasticity.
10.1016-j.jallcom.2021.162383	-1		In the present study, microstructure evolution and mechanical properties of the Cu-3Ag-xZr alloys processed by equal channel angular pressing (ECAP) at room temperature were investigated. The results indicated that significant grain refinement can be achieved, and the average grain sizes are remarkably refined to 0.41 +/- 0.1 mu m and 0.39 +/- 0.05 mu m after 8 P for Zr-free and Zr-containing alloys, respectively. The continuous dynamic recrystallization (CDRX) should be responsible for such refinement mechanism. For Zr-containing alloy, the original coarse island-like Cu4AgZr particles are crushed into nearly spherical particles with the average size less than 5 mu m during the subsequent deformation process. In addition, the Cu-3Ag-xZr alloys processed by ECAP after 8 P present the excellent comprehensive properties with yield strength of 587 MPa and 627 MPa, as well as the electrical conductivity of 84.5%ICAS and 70.7%ICAS for the Zr-free and Zr-containing alloys, respectively. Accordingly, a quantitative calculation based on the established strengthening mechanism was conducted, indicating that the significant strengthening effect originates from the formation of subgrain structure. It is anticipated that this research would provide a feasible way for the preparation of high-performance Cu-3Ag-xZr alloys.
10.1016-j.jallcom.2021.162701	-1		A near-full dense Cu-36.8Fe alloy was manufactured by selective laser melting (SLM). The as-SLMed Cu-Fe alloy exhibits an excellent combination of both high strength and superior ductility. The exceptional mechanical performances are associated with the unique hierarchical microstructures, including molten pools, sub-micron cellular bi-phasic structures and nano-scaled precipitates. The formation of hierarchical microstructures is presumably owing to rapid cooling rate of molten pool, repeat heating during SLM and intrinsically immiscible feature between Cu and Fe. These findings can provide insights for the application of SLM technique to other immiscible alloys and their design with higher mechanical performances.
10.1016-j.jallcom.2021.162729	-1		Cu-TiNi composites with TiNi volume percentages of 1%, 5%, 10% and 15% were prepared by vacuum hot pressing and hot extrusion. The microstructure, thermal and mechanical properties of the composites were analyzed. The results show that diffusion of elements occurred at the interface between the Cu matrix and the TiNi particles during the preparation process, leading to the formation of a (CuNi)Ti diffusion layer. The TiNi particles are uniformly distributed in the Cu-TiNi composites, with a well-bonded interface with the Cu matrix. Cu matrix has major < 111 > + minor < 001 > fiber textures after hot extrusion. There is a semi-coherent relationship between the Cu matrix and the (CuNi)Ti phase, with an orientation relationship of (111)(Cu)parallel to(103)((CuNi)Ti) and an angle of 18.7 degrees between the two crystal planes. Both the Vickers hardness and the compressive yield strength of the Cu-TiNi composites increased with increasing the volume percentage of the TiNi particles, while the thermal expansion coefficient showed an opposite trend. The thermal expansion coefficient, Vickers hardness and compressive yield strength of the Cu-15% TiNi composite are 14.11 x 10(-6) /K, 154.4 HV and 460.0 MPa, respectively. (C) 2021 Published by Elsevier B.V.
10.1016-j.jallcom.2021.162736	-1		Cu-15Ni-8Sn alloy ingots were prepared by vacuum melting, and the evolution behavior of gamma-D0(3) phase in casting and subsequent heat-treatment processes were systematically investigated, especially the key influencing factors of its distribution, morphology and quantity. Because of the Sn enrichment towards the solidification front, the particulate gamma-D0(3) phase would directly form from the molten alloy in the solidification process, while the lamellar and needlelike ones are then precipitated out from the supersaturated matrix in the post-solidification cooling process. After complete dissolution in the solid-solution treatment, the gamma-D0(3) phase would re-nucleate again at the grain boundary and grow into the adjacent grains in the aging process, forming discontinuous precipitation (DP) colony. The reduction of the number of nucleation sites and the decrease of the free energy difference could both inhibit the formation of gamma-D0(3) phase. As a result, an appropriate addition of B offers an ideal suppression effect, and leads to a decrease of DP content from 40 to 4 vol% after 16 h aging at 673 K. In terms of performance, for every 1 vol% decrease in DP content in the as-aged microstructure, the macro-hardness of alloy increases by 0.75 HB and the electrical conductivity decreases by 0.035% IACS. Furthermore, the in-coherent interface between alpha-FCC matrix and gamma-D0(3) phase is the weakest link in alloy, and it decreases the tensile strength from 890 to 760 MPa by increasing the DP content from 4 to 40 vol%.
10.1016-j.jallcom.2021.162799	-1		Grazing incidence X-ray diffraction (GIXRD) and scanning transmission electron microscopy (STEM) combined with energy dispersive X-ray spectroscopy (EDS) were employed to study the microstructure evolution and stress development in the nanocrystalline Cu100-X-Zr-X (2.5 at% <= x <= 5.5 at%) alloy thin films. Small Zr additions to Cu led to significant lattice parameter anisotropy in the as-deposited Cu-Zr thin films both due to macroscopic lattice strain and stacking faults in the Cu matrix. Strain free lattice parameters obtained after the XRD stress analysis of Cu-Zr thin films confirmed formation of a supersaturated substitutional Cu-Zr solid solution. For the first time, the study of film microstructure by XRD line profile analysis (XLPA) confirmed progressive generation of dislocations and planar faults with increasing Zr composition in Cu-Zr alloy films. These microstructural changes led to the generation of tensile stresses in the thin films along with considerable stress gradients across the films thicknesses which are quantified by the traditional d(Psi)(hkl)-Sin(2)Psi and GIXRD stress measurement methods. The origin of tensile stresses and stress gradients in the Cu-Zr film are discussed on the basis of film growth and heterogeneous microstructure with changing Zr composition. (C) 2021 Published by Elsevier B.V.
10.1016-j.jallcom.2021.163068	-1		Enthalpic interaction between the elements determines the stability of the local structures in the alloy system. Multicomponent synergistic effect is expected to improve the thermal stability and the relevant properties by regulating the enthalpic interaction. In this work, the composition of Cu-Ni-Sn alloys is explained by introducing the cluster-plus-glue-atom mode, and the strong and weak enthalpic interaction elements Si and Zn, respectively, are chosen for multi-componentization of Cu-Ni-Sn alloys. The results demonstrate that the synergistic effect of Zn and Si improves the stability of both the Cu matrix and D0(22) or L1(2-gamma') phase, inhibits the discontinuous precipitation effectively and gains a notable higher strength-over resistivity ratio (H-R / rho(R)) than the Cu-15Ni-8Sn (wt. %) (C72900) alloy. After adding Si and Zn, the reinforcing enthalpic interaction between the elements is the crucial factor for the stability enhancement of the alloys, and it is embodied by two aspects: (a) the reducing elastic strain energy in the solution treated alloys; (b) the more homogeneous surface potential and the higher work function in the age treated alloys. Additionally, Compared with the Cu80Ni15Sn5 alloy that based on the ideal cluster formula, the Cu79.68Ni15.63Sn4.69 alloy, based on the modified cluster formula: {[Cu-CuxNi12-x]Cu-3}(alpha){[Sn-NiyCu12-y]Sn-3}(16-a), possesses a preferable thermal stability whatever solution treated or age treated state, and exhibits a decreasing amount of discontinuous precipitation although has a slightly lower H-R / rho(R), which is beneficial to the improvement of the workability of the alloys. The modified cluster formula is more suitable for the compositional design of Cu-Ni-Sn alloys. The work provides an effective theoretical and experimental basis for the composition design of high stability Cu-Ni-Sn alloys.
10.1016-j.jallcom.2021.163160	-1		In this study, the texture evolution of CuNi alloy fabricated by rolling and annealing processes with different von Mises strains was systematically investigated by electron backscatter diffraction (EBSD). All the samples with different strains exhibited a strong cube texture after annealing at high temperatures, but the texture evolution trace was apparently affected by the strains. The most significant effect of the strain was the recrystallization nucleation of the cube texture. The distinct nucleation causes a different growth rate of the cube texture and the random texture, which causes a large temperature difference of 550-700 degrees C between the samples with different strains. This investigation allows us to better understand the texture evolution in CuNi and other FCC alloys after the rolling and annealing processes.
10.1016-j.jallcom.2021.163319	16	wear; composite; composites; powders; milling; particles; powder; wt; sliding; friction; hardness; matrix; mechanical; surface; properties	This study focused on the production of [Cu-10 Ni](x)-x wt% Si3N4 (x = 0, 3, 6, 9 and 12 wt%) nanocomposites through mechanical alloying followed by spark plasma sintering. An exhaustive exploration was carried out on the synthesised nanocrystalline/nanocomposite particles and sintered samples to study their structural characterisation and microstructural changes after 20 h of MA. The mechanical behaviour in terms of the compression test was carried out and correlated with the microstructural evaluations. The results indicated that the incorporation of Si3N4 nanoparticles decreased the matrix powder particle size considerably owing to the domination of fracturing mechanism. The results also showed that a higher strain hardening rate followed by the breaking up of the matrix powder particles occurred in the nanocomposite powders. The powder morphology of the nanocrystalline [Cu-10Ni] matrix ensured the uniform distribution of Si3N4 nanoparticles within it leading to the formation of dislocations in commensurate with the reinforcement addition. The sintered samples exhibited improved compression strength owing to the embedment of Si3N4 nanoparticles, strong bonding between the Si3N4 particles and the matrix, engendered dislocations and grain refinement. The ductility was examined and the strengthening mechanisms were computed for the deformed specimens. The results explained that the grain size, dislocation, and Orowan strengthening contributed more to the total strength and influenced the properties compared to other strengthening mechanisms.
10.1016-j.jallcom.2021.163328	-1		An oxide dispersion strengthened copper (ODS-Cu) alloy with Zr addition was fabricated by high-energy water-cooled mechanical alloying and spark plasma sintering (SPS). The effects of Zr addition on the material properties and microstructure of ODS-Cu alloys were investigated by comparing with the results of the Cu-1Y(2)O(3) (wt%) ODS alloy. The addition of 0.81 Zr (wt%) to the Cu-1Y(2)O(3) (wt%) alloy was confirmed to increase the Vickers hardness of the ODS-Cu alloy by a factor of 1.5, resulting in an unprecedented value of 243 HV. The excellent strength comes mainly from the strengthening effect caused by the refinement of the dispersed oxide particles. Fine and dense FCC-structured complex Y2Zr2O7 oxide particles were found to be uniformly distributed within the alloy, which are in good coherency with the Cu matrix, allowing the particle size to be less than half of that in Cu-1Y(2)O(3) (wt%) ODS alloy at 7.6 nm. Although a slight decrease in the thermal diffusivity of the ODS-Cu alloy with Zr was observed, which can be attributed to the solid solution effect of the residual Fe in the matrix, this study proposes a suitable thermal aging treatment to restore the thermal diffusivity by precipitating the solute Fe.
10.1016-j.jallcom.2021.163423	-1		This is the first report of the formation of a novel, hierarchical, three-level pore structure through the ordinary and simple processes of electroplating and dealloying. The co-deposition of Cu-Mn under certain conditions, allows the formation of Cu-rich and Mn-rich regions in unique distributions. By removing Mn and its oxides from the electrodeposited layer through dealloying, Cu with a hierarchical multi-porous structure is formed. This consists of wide and narrow macropore networks and mesopores. Notably, the growth of Cu and the resulting rapid depletion of Cu ions during the electroplating process are proposed to be the main reasons for the formation of interconnected pore networks. As the formation of this unique pore structure is essentially independent of the plating time (or the thickness of the deposited layer), and because it provides a very large surface area and open pore structure, its engineering practical applications particularly in functional chemistry and electrochemistry are expected to be significant in the future.
10.1016-j.jallcom.2021.163430	-1		This work studies the thermal stability of the microstructure and the evolution of the defects of two high-heat flux Cu-0.8 wt%Y alloys fabricated following two alternative powder metallurgy routes. One batch was produced by direct hot isostatic pressing (HIP) consolidation of Cu-0.8 wt%Y pre-alloyed atomized powders while an additional ball milling processing step was introduced before HIP sintering for the second alloy. The stability and recovery characteristics of the vacancy type defects in these alloys in the as-produced state and after processing by severe equal channel angular pressing to achieve a refine microstructure have been investigated by positron lifetime and coincidence Doppler broadening measurements in samples subjected to isochronal annealing from room temperature to 900 degrees C. Microhardness measurements and electron transmission microscopy analysis have also been performed to support the results obtained from the positron annihilation spectroscopy analysis techniques. The recovery curves of the positron lifetime and S-W plots show a recovery stage in agreement with the recovery stage V for Cu. However, a full recovery is not accomplished, and a stage that reverts the previous recovery takes place after annealing above similar to 600 degrees C, that leads to the formation of very stable defects at temperatures up to 900 degrees C, identified as vacancy aggregates and nanocavities. The characteristic shape of the coincidence Doppler broadening indicates that the dispersed Y-O particles in the Cu matrix appear to be responsible for stabilizing the vacancy aggregates and nanocavities for temperatures above 600-700 degrees C. (C) 2021 The Author(s). Published by Elsevier B.V.
10.1016-j.jallcom.2022.163636	15	aging; strength; conductivity; electrical conductivity; electrical; mpa; treatment; strengthening; degrees; cu-; cold; precipitation; tensile strength; tensile; iacs	The microstructure of Cu-Ni-Mn-P alloys prepared with different contents of Ni and Mn was explored by using EBSD-TEM-HADDF STEM and HRTEM. The findings revealed that the hardness of the Cu-Ni-Mn-P alloy was significantly increased by addition Ni or Mn. However, the conductivity was declined to vary degrees. The peak hardness of Cu-0.78Ni-0.32Mn-0.21P (NMP211) and 0.4Ni-0.81Mn-0.19P (NMP121) alloys were 176.8 and 178.1 HV,respectively, which is 9.1 and 10.4 HV higher than that of Cu-0.39Ni-0.29Mn-0.18P (NMP111) alloy. In addition, the softening temperature of NMP121 alloy was 530 degrees C, which is 25 degrees C higher than that of NMP111 alloy.TEM observation demonstrated that after aging the precipitates of NMP111, NMP211, and NMP121 alloys were calibrated as NiP phase. The phase relationship between the NiP phase and matrix was as (1 (1) over bar1)(NiP) // (0 (2) over tilde2)(Cu). With the addition of Ni, the precipitation phase became fine and dispersed, resulting in the improvement of the hardness of NMP211 alloy. XRD analysis showed that the addition of Mn increased the lattice distortion and hardness of NMP121 alloy and sharply decreased its conductivity. The addition of Mn inhibited coarsening of precipitates in high temperature environment, and increased the softening temperature of NMP121 alloy.
10.1016-j.jallcom.2022.163646	-1		Copper alloys that simultaneously possess excellent electrical conductivity, high strength and reasonable ductility are increasingly needed in aerospace, transportation and electronics industries. Unfortunately, these properties are usually mutually exclusive. Here, a strategy basing on constructing heterogeneous microstructures is proposed to overcome the above trade-off. Heterostructured Cu-Cr-Zr alloys, with micrometer-scale pure copper grains embedded inside a matrix of ultrafine copper grains with nanoscale precipitates are prepared via powder metallurgy. They show a high ultimate tensile strength of 458 MPa, which is higher than the prediction basing on rule of mixtures, meanwhile, retain a considerable ductility of 11% uniform elongation and an excellent electrical conductivity of 83.15% IACS. We further carried out loading-unloading-reloading tests and detailed microstructure characterizations to reveal the strain hardening mechanism induced by such heterogeneous microstructure. Our strategy indicates a promising route to achieve remarkable strength-conductivity-ductility synergy for copper alloys.
10.1016-j.jallcom.2022.163736	-1		In the paper, the preparation process for high-entropy alloy coatings in the field of electroless plating was explored. According to the method for designable alloy coatings, Al-induced electroless plating was used to create multilayer coatings. The thermal diffusion process was used to alloy the multilayer coatings. Therefore, multilayer coatings as a predesigned basic material for alloy coatings needed to be discussed first. Then, the alloying process of high-entropy alloy coatings was primarily investigated. In this paper, the CuCoNi alloy coating was the main object of research . The alloying process was characterised and analysed by scanning electron microscopy and X-ray diffraction. The corrosion resistance of the coating was measured by electrochemical tests. The results show that the element distribution and the phase peaks of the multilayer coatings gradually became homogeneous and stable during thermal diffusion. The alloying process was confirmed by these changes in morphology and structure. Alloy coatings were created with controlled element types and element proportions in electroless plating. The element types of the coatings can be controlled by the deposition composition, and the element proportions can be controlled by the deposition thickness. The corrosion resistance of the alloy coating was better than that of the single-element coating. At 6 h of thermal diffusion (which is the optimum diffusion time for the CuCoNi alloy coating), the corrosion potential was-0.218 V, and the corrosion current density was 2.72 mu A/cm(2). Based on the preparation process results, the design methods for high-entropy alloy coatings were proposed.
10.1016-j.jallcom.2022.163747	-1		A novel method for preparing lead-free Cu nano Bi (CNB) alloy materials by nano Bi powder and shift-speed ball milling (SSBM) flake powder metallurgy was proposed. To improve the mechanical and tribological properties of the alloy materials, the spherical CuSn10 powder was firstly extruded and sheared into flakes by low-speed ball milling (LSBM) in the SSBM system. Meanwhile, the nano Bi powder was evenly dispersed and coated on the CuSn10 flakes. The mechanical alloying between mixed powders and the cold welding of flake CuSn10 flakes containing nano Bi into layered particles were then realized through short-time highspeed ball milling (HSBM) in the SSBM system. While promoting the uniform dispersion of lubricating phase Bi, the surface area of matrix CuSn10 flake was increased so as to achieve better combination of CuSn10 matrix in the material. Results show that the mechanical properties of the CNB material prepared through nano Bi powder and SSBM flake powder metallurgy improved compared with the Cu-Bi material prepared by HSBM. In addition, the antifriction and wear resistance improved by 30% and 80%, respectively.
10.1016-j.jallcom.2022.163816	15	aging; strength; conductivity; electrical conductivity; electrical; mpa; treatment; strengthening; degrees; cu-; cold; precipitation; tensile strength; tensile; iacs	The effects of Y content on the microstructure and properties of Cu-0.9Cr and Cu-1.45Cr alloys were investigated systematically in present manuscript. Cu-Cr-(Y) alloys were prepared by vacuum melting and casting, solid solution treatment at 960 degrees C, (90% cold rolling) and aging treatment at 460 degrees C. The results indicate that the addition of 0.1 wt% Y refines the eutectic structure of as-cast Cu-0.9Cr and Cu-1.45Cr alloys. Besides, the hardness of Cu-Cr-(Y) alloys after solid solution treatment increases with the increase of the Y content. CRA (cold-rolling and aging) process can enhance the hardness of peak-aged alloys compared with SSA (solid solution and aging), the peak-aged hardness and corresponding conductivity of cold-rolled alloys slightly increase by addition of Y. Especially, when CRA for 300 min, the ultimate tensile strength, hardness of Cu-0.95Cr-0.1Y alloy (433 MPa, 146.8 HV) are superior to those of Cu-0.9Cr alloy (333 MPa, 102 HV), indicating that addition of Y significantly inhibits the over-aging during CRA. The TEM results reveal that Cr precipitates of FCC and BCC structures exist in the Cu-Cr-Y alloy aged for 300 min, and Y element suppresses the coarsening of Cr precipitates and the reduction of dislocation density. Moreover, the softening temperature of peak-aged Cu-Cr-Y alloys is similar to 70 degrees C higher than that of Cu-Cr alloys since the addition of Y inhibits the coarsening of Cr precipitates.
10.1016-j.jallcom.2022.163893	-1		High entropy alloys (HEAs) have attracted significant interest in recent decades due to their unique microstructures and many favorable properties, including high mechanical strength, good thermal stability and excellent corrosion resistance. In the present study, three Cu-Al based medium entropy alloys (MEAs), namely CuAlAg (CAA), CuAlZn (CAZ) and CuAlV (CAV), are deposited on glass substrates using a high vacuum sputtering system. The as-sputtered MEA films (MEAFs) are processed by Rapid Thermal Annealing (RTA) for 5 min in order to stabilize their microstructures and are then dewetted using a near infrared (NIR) fiber laser system with various repetition rates, pulse powers and scan speeds to produce nanoparticle structures. Finally, the antibacterial properties of the MEAFs and dewetted films are investigated using three bacterial strains, namely Escherichia coli, Pseudomonas aeruginosa and Staphylococcus aureus. It is shown that the particle size of the dewetted films decreases as the accumulated energy (AE) density increases. The smaller particle size leads to a blue shift of the localized surface plasmon resonance (LSPR) absorption peak wavelength as a result of the greater uniformity of the induced electromagnetic field. In the dewetting process, the Ag and Cu elements of the MEAFs form particles, while the Al atoms are repelled to the bottom or surrounding region of the nanoparticles, and the Zn and V atoms remain on the glass surface. The MEAFs and dewetted films show an antibacterial efficiency of 100% for all three bacterial strains after 24 h . Moreover, the bacterial growth curves indicate that the majority of the bacteria are destroyed within 4-5 h of contact. The antibacterial effect of the MEAFs and dewetted films is attributed to the production of reactive oxygen species (ROS) and the release of metal ions, which collectively destroy the cell membranes and lead to cell shrinkage and death . For all of the MEAFs, the antibacterial performance improves after dewetting as a result of the increased surface contact area provided by the nanoparticles. Overall, the present results confirm the effectiveness of MEAs and dewetted films in realizing thin-film coatings with enhanced antibacterial properties.
10.1016-j.jallcom.2022.163903	-1		A gradient nanostructured (GNS) surface layer was generated in a dual-phase Cu-Ag alloy by means of surface mechanical grinding treatment at liquid nitrogen temperature. With a decreasing depth in the surface layer, the coarse-grained microstructure of Cu matrix and Ag precipitates gradually converts into a nanolaminated structure of Ag-and Cu-rich phases with simultaneous chemical mixing, and finally forms a homogeneous single-phase supersaturated solid solution (SSS) nanostructure. Accordingly, a dislocation mediated transportation mechanism was proposed to dominate the chemical mixing of Ag and Cu atoms, i.e., dislocations interacting with solution atoms penetrate the Cu/Ag interface and glide in the neighboring solvent-phase lamella.
10.1016-j.jallcom.2022.163960	-1		Effects of heat treatment conditions on the microstructure evolution, phase transformation and mechanical properties of dual phase Cu-Zn alloy were systematically investigated. Meanwhile, the relationship between the nano-hardness and the macroscopic hardness was also discussed in the study. The results show that the beta phase rich in Zn, has the phase transformation temperature from 456.5 degrees C to 827.1 degrees C. With the increasing of heat treatment temperature, significant (200) (220) alpha phase to (200) (211) beta phase transformation occur and the beta phase fraction increases from as-received 13.1-41.3%. The grain becomes coarser and grows ra-pidly from 32.6 gm to 49.7 gm from temperature 550 degrees C to 800 degrees C, the increase of beta phase results in the strength increases and the fracture elongation decreases. The beta phase fraction has not varied significantly at temperature 750 degrees C and 800 degrees C, the strength has a further increase which is mainly attributed to a part of fine needles of Widmanstatten phase begin to form. At the same displacement, the beta phase exhibits a much larger load than that of the alpha phase, the material pile-ups around indent edges of the alpha phase becomes more evident indicating that the alpha phase is softer and has a better ductile. The big difference in the predicted hardness and the macroscopic hardness when heat treatment at 750 degrees C and 800 degrees C is mainly attributed to the formation of the fine needles of Widmanstatten phase.
10.1016-j.jallcom.2022.163983	-1		The influence of minor Ag addition on microstructure and properties of powder metallurgy Cu-10Fe alloy was investigated systematically. Minor Ag addition can give rise to finer and more homogenous distribution of Fe phase in Cu-10Fe-0.5Ag alloy. The resultant microstructure of Cu-10Fe-0.5Ag alloy can be ascribed to the increased vacancy density in Cu lattice and reduced interface energy of Cu/ Fe by Ag addition, which therefore increased the nucleation rate for Fe phase. Such microstructure of Cu-Fe-Ag alloy is also beneficial to increase both electrical conductivity and mechanical performance. The calculated activation energy from electrical conductivity is decreased from 56.23 kJ/mol of Cu-10Fe alloy to 28.30 kJ/mol of Cu-10Fe-0.5Ag alloy, suggesting the activated precipitation of Fe phase by Ag addition.
10.1016-j.jallcom.2022.164181	-1		The wide applications of Cu-10Ta (at%) composite are limited due to the high cost of Ta element (24 wt%). In the present research, Cu-0.6Ta-0.6Cr and Cu-0.6Ta alloys with low Ta content were fabricated by mechanical alloying and spark plasma sintering. The results indicate that the thermal stability and tensile strength of Cu-0.6Ta-0.6Cr alloy are significantly increased by the addition of Cr. The microstructure characterizations reveal that the performance enhancement of Cu-0.6Ta-0.6Cr alloy is ascribed to the transformation of nanoparticles in the matrix from Ta to more stable Cr2Ta Laves and the refinement effects of these nano particles from 19.4 nm to 14.1 nm. This work provides a potential for the wide applications of Cu-Ta alloy with low Ta by alloying with Cr at elevated temperatures.
10.1016-j.jallcom.2022.164401	-1		Although deformation twinning has been demonstrated to improve the strain hardening and ductility of metals and alloys with low stacking fault energies (SFEs), the optimum grain size for maximum strength-ductility combination still needs to explore. In this work, we selected Cu-30 wt% Zn alloy with extremely low SFE (7 mJm(-2)) acting as a model material. Specifically, Cu-30 wt% Zn samples with different grain sizes ranging from 628 nm to 30.6 mu m were prepared by equal-channel-angular pressing (ECAP) and subsequent annealing. Tensile test revealed that the maximum strength-ductility combination (ultimate tensile strength of 565 MPa and ductility of 20%) corresponds to a mean grain size of 3.8 mu m. Electron backscatter diffraction (EBSD) indicated that pre-existing annealing twins in fine-grained Cu-30 wt% Zn alloy annihilated at the initial deformation stage (< 10% tensile strain) via detwinning of thin twin lamellae (< 1 mu m) and conversion of twin boundaries of thick twin lamellae (> 1 mu m) into conventional high-angle grain boundaries. In the later stage of deformation (> 10% strain), deformation twinning occurred in grains with < 111 > orientation parallel to tensile direction, suggesting the combination of both detwinning and twinning deformations caused the maximum strength and ductility synergy. Our findings provide insights into optimization of strength and ductility of metals with low SFEs and detwinning-twinning deformation mechanisms.
10.1016-j.jallcom.2022.164680	-1		The effect of Si addition (0.2 wt%) on the precipitation evolution, mechanical properties and electrical conductivity of Cu-2.2Ni-0.4Be alloy were investigated, and the influencing mechanism was also discussed. The results show that Si can not only form delta phase with Ni, but also promote the nucleation and refine the size of NiBe phase, which increases the peak hardness from 282.3 HV to 308.2 HV. In addition, Si suppresses the NiBe phase coarsening under the over-aged condition, resulting in a much slower hardness and strength decline during the long time aging. Nevertheless, the electrical conductivity shows a slight decrease with Si addition, which is mainly attributed to the extra electronic scattering effect induced by the partial solution of Si.
10.1016-j.jallcom.2022.164683	-1		To pursue a combination of strength and plasticity, a near-eutectic high-entropy alloy Cu40Al20Ti20V20 was developed by using a stoichiometric ratio of the L21 Cu2AlTi ordered phase. The results showed that a softhard alternating BCC (alpha)+L21 (fi) dual-phase structure was realized. The as-cast alloy was composed of BCC (alpha p) dendrites, and a lamellar and rod-like BCC+L21 Cu2AlTi (alpha + fi) eutectic structure with a small amount of FCC Cu-rich phase embedded within. Due to the soft-hard dual-phase structure and large number of phase interfaces of the eutectic, the as-cast alloy possessed a high yield strength of 1300 MPa and plasticity of 6.3%. Annealing facilitated the precipitation of a substantial number of L21 nanoparticles (fiII) in the dendrites and the diffusion of Cu atoms from the Cu-rich phase to the matrix. The desolation transformation of fiII and the Cu diffusion during annealing increased the formation of excess L21 hard-phase to ~50 vol%. Many micro-pores were also formed, which facilitated crack initiation and deteriorated the strength and plasticity of the homogenized alloy.
10.1016-j.jallcom.2022.164761	-1		Powder metallurgy Cu-30Fe alloy was prepared by mechanical alloying, pressureless sintering, and rolling processes. The alloy microstructure and physical properties affected by rolling were studied. The Fe particles were small and uniformly distributed in the Cu matrix. The average Fe particle size in the sintered state was 1 mu m, and particles had subspherical or irregular shapes. The Fe particles became elongated, tadpole-shaped, and spindle-shaped as a result of rolling. At the same time, the Cu grains were elongated and refined, while the Cu grains near the Fe particles were finer as a result of the coordinated deformation of the soft Cu and hard Fe phases. After annealing at 400 degrees C, the cold-rolled Cu-30Fe alloy had 620 MPa tensile strength, 10% elongation, and 50% IACS electrical conductivity, achieving a good combination of mechanical and functional properties. The coordinated deformation behavior and grain refinement mechanisms of both Cu and Fe phases due to rolling were described, along with the microstructure and physical properties evolution.Published by Elsevier B.V.
10.1016-j.jallcom.2022.164800	16	wear; composite; composites; powders; milling; particles; powder; wt; sliding; friction; hardness; matrix; mechanical; surface; properties	Pure copper (Cu) and copper-carbon nanotube (Cu-CNTs) alloys were fabricated using laser powder bed fusion additive manufacturing (LPBF-AM) with a relatively high density. Their location-dependent (i.e., distance from build plate) microstructure and nanomechanical properties at room temperature were investigated. The microstructure of the as-build Cu showed ~40% lower porosity as compared to the AM CuCNTs. The amount of porosity was dependent on location for Cu sample with the bottom surface had ~61% lower porosity as compared to the top surface, however the change in porosity was negligible for as-build Cu-CNTs depending on the distance from the build plate. With the addition of 0.5 wt% CNTs, the mechanical properties of the composite were decreased slightly may be due to porosity, weak interfacial bonding of Cu and CNTs, CNT agglomeration, and degraded CNTs. Nanoindentation tests showed that the average modulus value and hardness of the composites were in the range of 40-80 GPa and 0.7-1.1 GPa, respectively depending on the strain rates and distance from the build plate; 18% and 25% decreases were achieved compared with pure copper, respectively. Creep displacement also increased for as-build Cu-CNTs as compared to the pure Cu. Further, for each system, increase in porosity led to increase in strain rate sensitivity and decrease in maximum creep displacement.
10.1016-j.jallcom.2022.164804	-1		ABS T R A C T This work attempted to strengthen the interfacial strength and mechanical properties of alumina whisker and graphene co-reinforced copper matrix composites by Cr matrix micro-alloying. Cr elements are ob-served to: (i) aggregate to form large particles rather than disperse uniformly in Cu matrix; (ii) disperse at interfaces between Cu matrix and reinforcements. The relative density, tensile strength, shear strength and compressive strength of the Cu-Cr composites were in direct proportional to Cr micro-alloying amount from 0 to 1.5 wt%. Increased Cr micro-alloying amount, on the one hand, can strengthen interfacial bonding between Cu matrix and reinforcements and thereby enhance the load transfer efficiency at interfaces; on the other hand, can yield obvious grain refinement, and thereby achieving grain boundary strengthening as well as twin boundary strengthening, which were considered as the dominant strengthening mechanisms of Cu-Cr composites. Besides, dislocation strengthening and solid-solution strengthening were also addi-tional strengthening mechanisms of Cu-Cr composites.
10.1016-j.jallcom.2022.164945	-1		High-performance Cu-Cr-Zr-X alloys are regarded as novel structural materials for nuclear fusion reactors. Through combining the experiments and density functional theory (DFT), the effect of Si addition on precipitation behavior and related properties of Cu-Cr-Zr-(Si) alloy was investigated for higher performance. Compared with the Si-free alloy, precipitation of Cr-rich phase is accelerated in the Cu-Cr-Zr-Si alloy (aging time < 30 min at 450 degrees C). The partial radial distribution functions of the Cu-rich matrix reveal that the formation of Si-Cr clusters is resulted from the attractive Si-Cr binding energies at the nearest-neighbor distance. Moreover, the addition of Si can reduce the Cr migration energy in Cu. At the initial stage of aging at 550 degrees C, the precipitation kinetics is dominated by temperature. By TEM analysis, it is indicated that the growth of Cr-rich phase in Cu-Cr-Zr-Si alloy is delayed, which may be attributed to the decrease of Cu/Cr interface energy due to the addition of Si, as confirmed by first-principles calculations. The optimized performance of aged Cu-Cr-Zr-Si alloy can be achieved at 450 degrees C/4 h, and Orowan strengthening is dominant. This work can provide a guideline for design of novel high-performance Cu-Cr-Zr-X alloys.
10.1016-j.jallcom.2022.165044	-1		Laser-arc hybrid additive manufacturing (LAHAM) of Cu-Cr-Zr alloy was studied. The microstructure evaluation and mechanical properties of the samples fabricated by LAHAM were analyzed compared with those prepared by wire arc additive manufacturing (WAAM). Columnar crystals growing along the building direction in both LAHAM and WAAM samples was observed. In the LAHAM sample, the grain size was refined and the maximum texture index and pole density intensity were reduced by 32.9% and 25.8% respectively compared with those in the WAAM sample. Meanwhile, it was found the uniform Cr precipitation, and the orientation relationship of precipitated Cr with Cu-matrix followed N-W relationship: (111) fcc.Cu // (110)bcc.Cr, [011]fcc.Cu //[001]bcc.Cr, which was conducive to the improvement of tensile properties of the LAHAM copper alloy. Compared with the WAAM sample, the ultimate strength and elongation of LAHAM sample increased by 11.6% and 13.1%, to 258.7 MPa and 41.8%, respectively. The improvement in ultimate strength was attributed to grain refinement and precipitation strengthening, and it was found the precipitation strengthening accounted for about 75% of the total strength enhancement and was the primarily strengthening mechanism in the LAHAM copper alloy.
10.1016-j.jallcom.2022.165085	-1		Microstructure and texture development of Al-Cu-Mg alloy with a high Cu/Mg ratio were investigated during homogenisation and hot rolling by using OM, SEM, DSC, XRD and TEM. The results showed that the Brass texture intensity increased by 2.4 times after hot rolling (90% rolling reduction), when the proportion of the second-phase particles in an area fraction and average particle size decreased from 1.32% to 0.24% and from 7.49 to 5.71 mu m before hot rolling, respectively. Large particles inhibited the activation of the {111} < 110 > slip system, which led to a decrease in texture intensity. When the reduction increased, the following activated slip systems and located area of slip traces were obtained: {111} < 110 > (at grain boundaries, 35% rolling reduction), {111} + {100} < 110 > (at local area of grains, 65% rolling reduction), and {111} + {110} < 110 > (in most grains, 90% rolling reduction). In addition, the amount of the slip system corresponding slip planes increased as the spacing of the slip traces per 200 nm gradually decreased, which helped enhance the intensities of Brass-and Copper-type textures.
10.1016-j.jallcom.2022.165170	-1		A dual-phase reinforced Cu-0.75 wt% Al2O3-0.75 wt% TiB2 composite ingot was prepared by liquid phase in-situ reaction casting method and then processed by hot rolling and cold rolling. The microstructure and property evolution of the composite during processing were investigated, and the strengthening mechanism was determined. Spherical Al2O3 particles with a size of 50 ~ 500 nm and irregular polygonal TiB2 particles with a size of 50 nm ~ 1.5 mu m were formed in the Cu matrix. When the cold rolling reduction exceeded 80%, the strengthening particles flowed with the plastic flow of the Cu matrix. The violent shear action between the particles and the Cu matrix made the particle agglomerations separate, which enhanced the uniform dispersion of strengthening particles. For the reduction of 90%, the tensile strength, yield strength, hardness, elongation and electrical conductivity were 477 MPa, 452 MPa, 158 HV, 5.7% and 80.0% IACS respectively. The strengthening mechanisms were dislocation strengthening, dispersion strengthening and subgrain strengthening in descending order. Liquid phase in-situ reaction casting combined with large-deformation rolling is a promising process for the preparation of dual-phase reinforced dispersion strengthened copper matrix composite. (c) 2022 Published by Elsevier B.V.
10.1016-j.jallcom.2022.165246	-1		Spark plasma sintering (SPS) is a promising method for producing high performance Cu-W composite with high copper and low tungsten content, which has wide application space in some occasions. Cu-20 wt%W composite with uniformly distributed ultrafine tungsten particles has been successfully fabricated under different spark plasma sintering temperatures. This paper deals with the impact of spark plasma sintering temperature on structure and performance characteristics of the composite. The intrinsic relationship between sintering temperature, microstructure and properties was studied. The results showed that the optimum SPS sintering temperature of Cu-20 wt%W composite powders produced by spray drying method is 950 degrees C. When the sintering temperature was increased, the content of copper-liquid would be increased, which could not only accelerate the rearrangement of tungsten particles but fill the holes to improve the performance of Cu-20 wt%W composite. However, a much higher temperature may lead to the sintering between tungsten particles, coarse copper net and the existence of copper vapor, ultimately resulting in the inhomogeneous distribution of tungsten and copper phases and the downward trajectory of the performance of the composite. The sintering mechanism was investigated and concluded with a detailed discussion. (c) 2022 Published by Elsevier B.V.
10.1016-j.jallcom.2022.165274	15	aging; strength; conductivity; electrical conductivity; electrical; mpa; treatment; strengthening; degrees; cu-; cold; precipitation; tensile strength; tensile; iacs	In this study, Cu-Cr-Mg alloy wires were prepared by up-drawing continuous casting and multi-pass drawing. The effect of the solid solution process on the strength and electrical conductivity of the Cu-Cr-Mg alloy was investigated. The solid solution degree of Cu-Cr-Mg alloys with different solid solution processes was evaluated by XRD. The types and morphologies of nanoprecipitates of the two alloys during different thermomechanical treatments were compared by selected area electron diffraction in TEM, and the degree of recrystallization of the peak-aged Cu-Cr-Mg alloy was analyzed by EBSD. The results showed that the degree of supersaturated solid solution of the as-cast Cu-Cr-Mg alloy was comparable to that of the as-cast Cu-Cr-Mg alloy after holding at 950. for 1 h and water quenching. Meanwhile, the strength of the as-cast Cu-Cr-Mg alloy was 52.2 MPa higher than that of the solution-treated Cu-Cr-Mg alloy, and the decrease in conductivity was only 6.3% IACS. The microstructure results showed that a large number of dispersed nanoscale precipitates existed in the matrix of both alloys, and the precipitates were close in size. The results of the strengthened model calculations are also close to the experimental results.
10.1016-j.jallcom.2022.165276	1	shape; memory; shape memory; damping; martensite; martensitic; damping capacity; transformation; capacity; strain; superelasticity; temperature; cu-al-mn; shape memory effect; effect	Previous work did not identify occurrence stage and degree of martensitic stabilization in Cu-based shape memory alloys due to lower heating rate. By flash heating into liquid metals, we systematically clarified contribution of static ageing and the ones of dynamic ageing during process of quenching and heating to the martensitic stabilization in directly-quenched CuZnAl alloys. We discovered that the dynamic ageing during the cooling process of quenching could instantaneously stabilize a few already formed martensites totally although it did not stabilize the overwhelming majority of martensites. The dynamic ageing during the process of subsequent slow heating was responsible for the partial and total stabilization of overwhelming majority of martensites. Both the amounts of martensites stabilized totally by the two dynamic ageing positively depended on Ms temperature. The conventional up-quenching into oil or air actually made more martensites stabilized due to the dynamic ageing during the process of slow heating. The increase in As temperature owing to the static ageing also positively depended on the Ms temperature. These dependences cannot be explained by two well-known mechanisms for the martensitic stabilization. (c) 2022 Published by Elsevier B.V.
10.1016-j.jallcom.2022.165401	1	shape; memory; shape memory; damping; martensite; martensitic; damping capacity; transformation; capacity; strain; superelasticity; temperature; cu-al-mn; shape memory effect; effect	Present proposed mechanisms for ageing-induced martensitic stabilization cannot explain why the amount of martensites losing reverse transformation ability (RTA) positively depended on Ms temperatures in directly-quenched CuZnAl alloys owing to dynamic ageing during the cooling process of quenching and subsequent slow heating. We proposed and confirmed that the number of vacancies at martensites boundaries (N-vmb) was the key factor controlling the occurrence of martensitic stabilization and its resulting RTA or loss in shape memory effect, not the number of vacancies inside the martensites and their long-range diffusion. All reported results can be rationalized by the positive dependence of original N-vmb on the Ms temperature. (C) 2022 Published by Elsevier B.V.
10.1016-j.jallcom.2022.165408	-1		The effects of yttrium on the cellular precipitation kinetics, grain growth behavior and mechanical properties of Cu-15Ni-8Sn alloy are investigated. Results show that the added yttrium leads to the formation of NiSnY and Ni2Y compounds, which increases the strength, refines the grains and slows the grain growth rate of the Cu-15Ni-8Sn alloy. Also, the addition of yttrium changes the nucleation rate and crystal growth type of the gamma phase, postponing cellular precipitation in the early stages of aging treatment. Compared with the peak-aged Cu-15Ni-8Sn alloy, the peak-aged Cu-15Ni-8Sn-0.2Y alloy possesses higher hardness and strength . The hardness increases from 348 HV to 372.2 HV, the yield strength increases from 960 MPa to 1098 MPa, and the ultimate tensile strength increases from 1044 MPa to 1166 MPa. (C) 2022 Published by Elsevier B.V.
10.1016-j.jallcom.2022.165409	-1		The effects of fibrous Cr phase on the adiabatic shearing anisotropic behavior of the Cu-15Cr in-situ composite model alloy were firstly studied by a split Hopkinson pressure bar (SHPB), Optical Microscope (OM), and X-ray diffraction (XRD) technique. Specimens were loaded along the rolling direction (Cu-15Cr0 degrees) and perpendicular to the rolling direction (Cu-15Cr-90 degrees). The experimental and analysis results showed that there were differences in the number of phase interfaces and phase interface distance that the shear stress crossed when sheared along with different directions due to the directional arrangement of the fibrous Cr phases, which caused the strain hardening, strain rate hardening and thermal softening of the Cu15Cr in-situ composite were anisotropic. The Cu-15Cr-90 degrees specimen possessed lower strain rate hardening and higher thermal softening at the same strain rate, and the strain hardening rate was similar to that of the Cu-15Cr-0 degrees specimen as the shearing process proceeded, so the Cu-15Cr-90 degrees specimen was more prone to adiabatic shearing than the Cu-15Cr-0 degrees specimen. In addition, a splitting crack was produced at the Cr phase and matrix interface in the Cu-15Cr-0 degrees specimen due to the additional tensile stress produced in the Cr phase during shearing. The perpendicular Cr phase in the Cu-15Cr-90 degrees specimen was deflected parallel to the shear stress during shearing, so it was not easy to produce splitting cracks. However, the tip of the Cr phase without deflection was more likely to possess high additional tensile stress, so the crack in the Cu15Cr-90 degrees specimen was extended along the edge of the adiabatic shear region at the tip of the Cr phase.
10.1016-j.jallcom.2022.165462	2	corrosion; surface; film; electrochemical; films; spectroscopy; layer; current; solution; potential; resistance; composition; x-ray; ions; showed	Copper-iron alloys were produced at room temperature by means of electrodeposition of iron on a copper substrate in an ionic liquid (1-butyl-1-methylpyrrolidinium trifluoromethylsulfonate [Py-1,Py-4]TfO). Samples with different electrodeposition times were studied using mechanical spectroscopy, scanning electron microscopy, light microscopy and magnetic loops techniques. Independent of the electrodeposition time the electrodeposition process leads to the promotion of a thin layer of iron onto the copper surface without iron diffusion into the substrate. The damping spectra for electrosposited samples in the as-electrodeposited state show the characteristic low and intermediate grain boundary damping peaks from copper as well as the solvent grain boundary damping peak from the electrodeposited iron. Thermal annealing at tempera-tures near 973 K leads to the appearance of Fe particles at the interface between the copper and iron (Cu + alpha-Fe phase) leading to a new damping peak at around 680 K whose driving force is the diffusion of copper atoms around the second phase particles.
10.1016-j.jallcom.2022.165780	-1		The effects of hot-rolling on the secondary electron property evolution of activated Cu-2.7Be sheets were investigated in this study. The microstructures of both pristine and activated Cu-2.7Be alloys subjected to different hot-rolling temperatures were characterized. Their phase compositions were found to comprise an alpha matrix and eutectoid phases (alpha + gamma). Using electron back-scattered diffraction, the initial average grain size (d(0)) was found to vary from 6.45 mu m to 15.63 mu m as the hot-rolling temperature increased from 680 degrees C to 830 degrees C. Scanning electron microscopy and X-ray photoelectron spectroscopy studies of the activated Cu-2.7Be sheets revealed that the amount of BeO increased with a decrease in the average grain size, resulting in the enhancement of the peak secondary electron emission yield. Scanning Kelvin probe force microscopy measurements confirmed that the main contributor to the BeO enhancement was the a matrix, while transmission electron microscopy analysis showed that BeO formed preferentially from sub-grain boundaries, indicating the importance of grain boundaries for BeO formation. Moreover, the peak secondary electron yield (delta(m)) exhibited a linear relationship with d(0)(-0.5) similar to the Hall-Petch relation. The results in this study will be important for enhancing the secondary electron yield of Cu-Be dynodes used in photo-multiplier tubes and electron multipliers. (c) 2022 Published by Elsevier B.V.
10.1016-j.jallcom.2022.165957	-1		The anisotropy of microstructure, electrical conductivity and mechanical properties of Cu-Cr-Zr alloys under different scanning strategies were comprehensively investigated. The effect of different scanning strategies on the evolution of the microstructure and properties of Cu-Cr-Zr alloys manufactured by laser powder bed fusion was explored. The microstructure, electrical conductivity and mechanical properties of the specimens exhibited different anisotropy under different scanning strategies. Compared with specimens using the meander scanning strategy, the epitaxially grown columnar grains on the vertical plane of specimens using the chessboard scanning strategy are significantly tortuous. The strength anisotropy of the specimen can be attributed to the combined effect of the anisotropy of the strengthening mechanism and crystallographic texture. The anisotropy of the ductility of the specimen can be attributed to the anisotropy of the deformation mechanism of the grains and the difference in the fracture mechanism. The anisotropy of the electrical conductivity of the specimen can be attributed to the different degrees of lattice distortion.
10.1016-j.jallcom.2022.166059	15	aging; strength; conductivity; electrical conductivity; electrical; mpa; treatment; strengthening; degrees; cu-; cold; precipitation; tensile strength; tensile; iacs	A Cu-3.0 wt% Ti alloy is fabricated by a novel non-vacuum short-process based on heating-cooling combined mold (HCCM) continuous casting in this study. Similar properties including tensile strength, hardness and electrical conductivity are obtained by this newly developed process, compared to its counterpart alloy prepared by conventional vacuum smelting. The tensile strength, total elongation and conductivity of the HCCM prepared Cu-3 wt% Ti alloy were 895 MPa, 13% and 13.00% IACS, respectively, after 95% deformation and aging treatment at 450 degrees C for 1 h . The cast materials fabricated by HCCM method can be directly cold rolled and aged after solution treatment without hot deformation such as hot forging. Through the HCCM continuous casting method, not only the Cu-Ti alloy can be fabricated under non-vacuum conditions, but also the fabrication process can apparently shortened by shortening the solid solution treatment time. Similar precipitation process is also found in the Cu-3.0 wt% Ti alloy prepared by this method. The precipitation of the ordered, metastable and coherent beta'-Cu(4)Tiphase with body-centered tetragonal (bct) structure are formed in the early stage of aging treatment, which is transformed into stable beta-Cu3Ti with an orthogonal structure in the over-aging stage. The precipitation hardening of beta'-Cu4Ti phase, i.e., Orowan strengthening effect, is believed to be the leading strengthening mechanism in this alloy. (C) 2022 Published by Elsevier B.V.
10.1016-j.jallcom.2022.166124	-1		Cu-Ni-Al alloys with a Ni to Al ratio of approximately 3.0 are of particular interest for the development of electrically conductive products; thus, investigating their phase behavior is essential for achieving specific properties in these materials. In this study, the phase diagram of the Cu-Ni3Al pseudo-binary system was experimentally determined using cast and fully heat-treated Cu-Ni3Al alloys with a wide range of compositions, via microstructural observation and different quantitative analyses. The Cu-Ni3Al system undergoes a eutectic reaction Liquid ? alpha-Cu solid solution (Cu-ss) with an FCC structure +gamma '-Ni3Al with an ordered FCC L1(2 )structure. As the combined Ni and Al (Ni3Al) content increased, the microstructure transitioned from a single alpha-Cuss phase to two eutectic phases (alpha-Cuss and gamma '-Ni3Al), to a primary gamma '-Ni3Al phase and two eutectic phases, and to a single gamma '-Ni3Al phase. The solidus and liquidus temperatures increased with the (Ni+Al) content. The solid solubility of (Ni+Al) in the alpha-Cuss phase (C(Ni+Al)) could be described by an Arrhenius-type equation (ln C(Ni+Al) = 5.50-2637/T), indicating a significant temperature dependence. In contrast, the solubility of Cu in the gamma '-Ni3Al phase did not significantly decrease with the temperature. The phase diagram of the Cu-Ni3Al system was constructed from these results. The phase diagram will be useful in the development of Cu-Ni-Al alloys with exceptional strength and electrical conductivity.
10.1016-j.jallcom.2022.166156	-1		The texture of deformation and primary recrystallization in copper-nickel alloys with the addition of a small amount of refractory elements such as Nb, Mo, Ta and W was studied. Based on the X-ray analysis of the deformation texture using the orientation distribution function, it was shown that the volume fraction of the C and S components in alloys is greater than the double volume fraction of the unfavorable component B. In accordance with this criterion, after primary recrystallization in all the studied alloys, a sharp cubic texture {100} < 001 > was obtained with a volume fraction in the +/- 10 degrees region of more than 95%. Alloying with refractory elements significantly increases the strength of the base copper-nickel alloy by the me-chanism of solid-solution hardening. The evaluation of the mechanical characteristics showed that the increase in the yield stress in the studied alloys is from 25% to 45% with relative to Cu-40% Ni alloy.(c) 2022 Published by Elsevier B.V.
10.1016-j.jallcom.2022.166163	0	solidification; phase; magnetic; magnetic field; undercooling; field; liquid; separation; peritectic; immiscible; cu-; dendrite; phase separation; microstructure; primary	In the present study, the effect of C micro-alloying on microstructure evolution and properties of metastable immiscible Cu-20Fe alloy was comprehensively investigated. Experimental results indicate that the mi-crostructure of Cu-Fe alloy is extremely sensitive to the C content. It was found that obvious liquid-liquid phase separation (LLPS) behavior is observed in Cu-20Fe alloy after C micro-alloying, and the tendency of LLPS is enhanced with increasing C content. The calculation of Delta Scc(0) suggests that C atoms preferentially pair with free Fe atoms to form new Fe (C) atomic clusters, thus resulting in the enhancement of bonding of the like-atom pairs. In addition, the quasi-binary phase diagram calculation further reveals the existence of a stable miscibility gap for C-containing alloys, and the temperature interval of miscibility gap is sig-nificantly enlarged with increasing C content. Meanwhile, the interface energy between two liquids formed by LLPS also slightly increases as C content increasing. These above reasons should be responsible for the microstructure evolution of Cu-20Fe-xC alloys. In addition, the C micro-alloying deteriorates the soft magnetic properties of Cu-Fe alloys to a certain extent, whereas improves its corresponding wear -re-sistance.
10.1016-j.jallcom.2022.166214	-1		Magnetic spinodal alloys are ideal materials for studying the relationship between the microstructure of an alloy and its magnetic properties. To unravel this relation, a profound knowledge of the chemical as well as the magnetic microstructure, i.e. the magnetic domain structure, is necessary. However, mapping the magnetic domain structure is rarely accomplished even though it is of major interest for both, fundamental research as well as applications using such alloys. In this study, the magnetic domain structure as well as the evolution of the microstructure of spinodally decomposed Cu52Ni34Fe14 alloys is investigated with various modern (scanning) transmission electron microscopy ((S)TEM) methods. The magnetic domain structure was mapped using differential phase contrast imaging (STEM DPC) and magnetic-force microscopy (MFM). The chemical microstructure was determined using high-angle annular dark field imaging (HAADF) and energy-dispersive X-ray spectroscopy (EDXS) elemental mapping. (C) 2022 The Author(s). Published by Elsevier B.V.
10.1016-j.jallcom.2022.166228	3	sma; shape; shape memory; memory; smas; superelastic; bars; damping; cu-al-mn; mechanical; bending; applications; numerical; sma bars; material	Transforming a 3D-printed part into a pre-programmed shape over time is called four-dimensional (4D) printing. Shape memory alloy (SMA) is most commonly used material for 4D printing. However, metalbased SMAs exhibit lower recovered strain during 4D printing compared to shape memory polymers, thereby requiring enhanced recovery in metal-based SMAs. In this study, a novel two-functional Cu-Al-Ni SMA consisting of two separate structures fabricated by powder bed fusion process was investigated to enhance the recovery in SMAs. The binding morphology of the two structures and subsequent consequences on the 4D printing behavior were analyzed. The first structure recovered at a lower temperature, whereas the second structure recovered at a higher temperature. In the case of the two-functional material, the difference in the hardness values and recovery temperature favored the recovery ratio due to the damping behavior of the harder structure and the generation of a temperature gradient across the deformation section. Additionally, the higher residual stresses obtained in the harder structure by simulation proved the mismatch between the two structures, leading to resistance against plastic deformation. Meanwhile, the formation of secondary martensite plates was observed in the second structure of the twofunctional material. These secondary martensite plates enhanced the overall recovery by (i) the attenuation of thermal conductivity across the deformation section and generation of the temperature gradient, and (ii) the increase in residual stresses and mismatch between the two joined structures.
10.1016-j.jallcom.2022.166258	-1		Shape Memory Alloys (SMAs) are smart materials that involve a transition from the martensitic phase to the austenitic phase when induced by a change in temperature or stress. SMAs have been proven to possess damping properties, which is caused by the internal friction that occurs in the martensitic phase. This work focuses on exploring the damping properties of some copper-based ternary and quaternary SMAs using Dynamic Mechanical Analysis (DMA) by calculating internal friction. The results show that the peak value of damping lies near to the martensitic start temperature of the respective alloys. The addition of quaternary elements (Ni and Mn) to the existing ternary alloy decreases the transformation temperatures, thereby decreasing the temperature at which the peak damping value occurs. The Ni-Ti alloy attains its peak value of damping at temperatures lower than the temperatures at which peak value is attained for these alloys. Therefore, the results prove that the alloys developed are promising materials for damping applications which can be used over a wide range of temperatures.
10.1016-j.jallcom.2022.166273	-1		The structural stability of nano-grained Cu-Al alloy synthesized by ball milling under liquid nitrogen temperature was analyzed. The hardness of the alloy drops only 6 % after annealing at 1173 K for 30 min, in comparison to the as-milled condition. X-ray diffraction (XRD), transmission electron microscopy (TEM), and Molecular dynamics (MD) simulation was incorporated to get an insight into the enhanced thermal stabilization of the alloy. Cryogenic ball milling introduces extensive deformation twins in the micro-structure and a significant amount of twins are present after annealing. The retained nanoscale twins along with the annealing induced Al2Cu nano-precipitate synergistically contribute toward the structural stability of the alloy.
10.1016-j.jallcom.2022.166410	15	aging; strength; conductivity; electrical conductivity; electrical; mpa; treatment; strengthening; degrees; cu-; cold; precipitation; tensile strength; tensile; iacs	Microalloying is an effective method for enhancing the mechanical properties and softening resistance of alloys. The effects of microalloying with Al, Zn, and Si on the microstructure, physical properties, and softening resistance of Cu-Ni-Sn alloy were investigated. The results showed that the micro-alloying of Al, Zn, and Si suppressed the segregation of the Cu-Ni-Sn alloy. After 70% cold rolling and 400 degrees C aging, the Cu15Ni-5.5Sn-1.5Al-0.5Zn-0.5Si alloy reaches its maximum hardness of 418 HV, which is 16 HV and 38 HV higher than that of Cu-15Ni-8Sn and Cu-15Ni-5.5Sn alloys, respectively. Furthermore, Al, Zn, and Si microalloying can increase the softening temperature of Cu-Ni-Sn alloy. Cu-15Ni-5.5Sn-1.5Al-0.5Zn-0.5Si alloy's softening temperature was 560 degrees C, which was higher than Cu-15Ni-8Sn (400 degrees C) and Cu-15Ni-5.5Sn (420 degrees C) alloys. The softening of the alloy is mainly caused by the rapid formation of discontinuous precipitates and the reduction of dislocation density. The Al and Zn solute atoms dissolved in the matrix and the micron-scale Ni31Si12 phase forms can effectively inhibit discontinuous precipitation formation and dislocation movement during the aging and annealing process, resulting in excellent mechanical properties and softening resistance of the Cu-15Ni-5.5Sn-1.5Al-0.5Zn-0.5Si alloy. In further works, continued efforts are needed in the multi-component design of Cu-Ni-Sn-x alloy to optimize its comprehensive performance. (c) 2022 Published by Elsevier B.V.
10.1016-j.jallcom.2022.166413	-1		In this research, ultrafine-grained Cu-7at%Al-3at%Ni alloys with a twin structure and precipitates were prepared by cold rolling+aging+cold rolling+aging (CR+ACA) and multi-directional forging+aging+cold rolling+aging (MDF+ACA). In contrast with un-deformation sample, significant increases in strength were obtained by MDF+ACA and CR+ACA, reaching 803.7 MPa and 722.8 MPa respectively, while maintaining a good elongation of 9.5 % and 8.4 %. Compared with CR+ACA, this is noted that a synergistic improvment in strength and elongation is achieved after MDF+ACA. The effect of microstructure on strength and elongation was investigated and the contribution of each strengthening mechanism for strength was analysed. The results show that the enhancement in strength is due to the increased dislocation density as well as de-creasing grain size formed in the MDF+ACA process. The higher twinning fraction in the sample after MDF +ACA leads to an increase in elongation due to the ability of twins to storage dislocations which can increase the strain hardening capability of the alloy. In addition, the current work describes a refinement mechanism for obtaining ultra-fine grains using these two different deformation processes by phase-field crystal (PFC) method simulation. The results of this study will help in further preparation of copper alloys with synergistic improvement strength and elongation.
10.1016-j.jallcom.2022.166574	4	transformation; martensite; martensitic; phase; shape; beta; memory; shape memory; temperature; temperatures; martensitic transformation; gamma; transformation temperatures; effect; thermal	Cu-26Zn-5Al shape memory alloy (SMA) was produced by accumulative roll bonding (ARB) and subsequent heat treatment. In this regard, different austenitization cycles and cooling conditions, including furnace, air, cold-water, and boiling-water cooling were experimented. The heat-treated specimens were characterized by scanning electron microscopy (SEM), differential scanning calorimetry (DSC), and X-ray diffraction (XRD). The corrosion behavior of the specimens was also studied by potentiodynamic polarization and electrochemical impedance spectroscopy (EIS) in a 3.5 wt% NaCl solution. The results revealed that only by cooling in the boiling- and ice-water environments, a fully martensitic microstructure showing the shape memory effect is obtained. In contrast, by using the other cooling conditions, different phases like alpha-phase (Cu-saturated solid solution) are formed as well as martensite. From the corrosion testing results, it was found that the SMA specimens with the fully martensitic microstructure have the highest corrosion re-sistance, where cooling in boiling water was recognized to be optimal. In conclusion, Cu-26Zn-5Al SMA with an improved corrosion resistance can be produced by ARB followed by controlled heat treatment. (c) 2022 Published by Elsevier B.V.
10.1016-j.jallcom.2022.166587	15	aging; strength; conductivity; electrical conductivity; electrical; mpa; treatment; strengthening; degrees; cu-; cold; precipitation; tensile strength; tensile; iacs	A new process of accumulative roll bonding-deformation diffusion (ARB-DD) with subsequent deformation diffusion heat treatment was proposed to solve the problem of poor composition homogeneity of alloys prepared by conventional accumulative roll bonding-diffusion heat treatment (ARB-DHT). The effects of ARB-DHT and ARB-DD on compositional homogeneity of Cu-Ti alloys were studied in comparison. And the mechanism of compositional homogeneity evolution of ARB-DDed Cu-Ti alloy was revealed. The results show that elements in Cu-Ti alloys prepared by the conventional ARB-DHT process are enriched and show a more obvious periodic distribution characteristic, and the compositional homogenization is poor. However, in ARB-DD process, the deformation process drives the Taylor lattice to reopen and form high-density nano-twin with a lamella width of 50-90 nm. Further, the high density of dislocations and stacking faults pro-vides high diffusion rate channels for element diffusion, which effectively facilitates the diffusion and redistribution of elements in the subsequent diffusion heat treatment process and accelerates the compositional homogenization. On the contrary, in comparison with the conventional ARB-DHT process which promotes element diffusion through thermal effects, the ARB-DD process uses the synergistic effects of thermal and deformation effects to promote element diffusion, effectively enhancing the degree of compositional homogenization.
10.1016-j.jallcom.2022.166595	15	aging; strength; conductivity; electrical conductivity; electrical; mpa; treatment; strengthening; degrees; cu-; cold; precipitation; tensile strength; tensile; iacs	Cu alloys with high strength, high electrical conductivity (EC) and good softening resistance (SR) are urgently needed in many fields. A Cu-1.06 wt% Fe-0.44 wt% Ti alloy was designed concerning the calculation of phase diagrams. It was expected that the Fe2Ti phases could precipitate to obtain high performance. The designed alloy was prepared and it obtained the most excellent properties of 211 HV hardness, 542 MPa tensile strength, 9.8% uniform elongation, 79% IACS EC and 575 degrees C softening temperature after solid solu-tion, cold rolling (90% reduction of thickness) and aging at 450 degrees C for 24 h . The Fe2Ti phases indeed pre-cipitated in the Cu matrix, which proved the alloy design idea. The precipitation kinetics, interaction between recrystallization and precipitation, and the effects of precipitation on strength, EC and SR were discussed. It was concluded that the precipitation driving force of the Fe2Ti phase itself in Cu was weak, and the cold rolling could significantly promote the precipitation. The precipitation of Fe2Ti slowed down the recrystallization to a certain extent. The high strength and high EC were mainly due to the precipitation strengthening and purification effects of the Fe2Ti precipitation on the Cu matrix. Besides, the good SR was mainly due to the low diffusion rate of Fe in Cu and the weak precipitation driving force of Fe2Ti.
10.1016-j.jallcom.2022.166829	-1		The rapid solidification behaviour of binary aluminum copper alloys in the hypoeutectic range of compo-sitions has been studied in this work. Solidification at cooling rates up to 40,000 & DEG;Cs-1 can be achieved using a chip-based calorimeter, but present challenges in sample preparation and temperature correction, which are addressed in this work. Data from calorimetry has been used to produce fraction of solid curves which are important input to metal manufacturing processing models. Undercoolings range from around 50 & DEG;C at 100 & DEG;Cs-1 to around 100 & DEG;C at 40,000 & DEG;Cs-1. From these, a kinetic phase diagram was constructed for the hypoeutectic region of the Al-Cu system, for cooling rates up to 40,000 & DEG;Cs-1. The undercoolings measured in this experiment are considerably higher than those predicted theoretically for growth-based rapid so-lidification, but not as high as those predicted under homogeneous nucleation.
10.1016-j.jallcom.2022.166836	15	aging; strength; conductivity; electrical conductivity; electrical; mpa; treatment; strengthening; degrees; cu-; cold; precipitation; tensile strength; tensile; iacs	In this study, Cu-0.8Cr-0.1Zr alloy was prepared by vacuum horizontal continuous casting method. The effect of different thermo-mechanical treatment processes on the properties was studied, and the micro-structure evolution at different stages of thermo-mechanical treatment were observed by SEM, EBSD and (HR)TEM. The results showed that the optimal comprehensive performance of tensile strength (803 MPa) and conductivity (76% IACS) was obtained by three-stage drawing and thermal treatment (primary 43.75% drawing and solution treatment at 950 degrees C for 60 min + secondary 97.2% drawing and aging at 500 degrees C for 30 min + tertiary 75% drawing). Through the microstructure characterization, it was found that the mor-phology and distribution of the Cr-rich primary phase can be regulated by solution treatment, and inherited during the thermo-mechanical treatment. It acts as a nucleation point and hard point, thereby refining the grain and improving the strength of the alloy. Additionally, it reduces the number of solid solution atoms in the matrix and prevents the loss of conductivity. Furthermore, drawing with a large amount of deformation can produce a nano-lamellar structure with high temperature stability, and drawing after high temperature aging can induce substructure formation. The combination of nano-lamellar structure and substructure further improves the strength .
10.1016-j.jallcom.2022.166940	6	grain; deformation; strain; strength; dislocation; cu-; tensile; size; ecap; grain size; sfe; ductility; hardening; high; stress	A Cu-2.5Ti-0.4Cr-0.1Mg (wt%) alloy was prepared in a vacuum medium frequency induction furnace. The evolution of the microstructure and mechanical properties of the samples deformed by equal channel angular pressing (ECAP) at different temperatures was investigated by hardness tests, tensile tests, optical metallography observation, X-ray diffraction and electron back-scattered diffraction. The cryogenic -tem-perature-deformed (CDed) samples have a little higher hardness than room-temperature-deformed (RDed) samples at any given ECAP pass. After 8 ECAP passes, the yield strength of CDed and RDed samples is close to each other, with the value of 812 +/- 17 MPa and 793 +/- 25 MPa, respectively. ECAP deformation sig-nificantly refines the grain size of the alloy due to the dislocation subdivision and twin fragmentation, and the average grain sizes of RDed and CDed samples after 8 passes are about 0.32 mu m and 0.37 mu m, respec-tively. Calculation results show that dislocation strengthening plays a key role in increasing the strength of ECAPed samples.
10.1016-j.jallcom.2022.167007	7	irradiation; shear; grain; ta; deformation; size; radiation; voids; nanocrystalline; simulations; similar; void; temperature; irradiated; boundaries	An interplay between high degree of shear deformation and deformation-induced heating occurs during friction stir processing (FSP) of metals. In medium-to-low stacking fault energy Cu alloys, this can lead to a complex spatially heterogenous activation of dynamic recrystallization (DRX) and twinning mechanisms. Within the Cu-Nb system, the presence of Nb is further expected to influence the DRX mechanism of the Cu matrix. However, the microstructural changes induced by the co-deformation of Nb during FSP are still not well understood. Therefore, this study uses a combination of multimodal microstructural characterization, solution thermodynamics-based predictions, and computational crystal plasticity simulation to reveal the various microstructural evolution mechanisms that can occur during FSP of a Cu-4at%Nb binary model alloy. The formation of softer DRX zones, and harder shear localization regions are revealed using electron backscatter diffraction, transmission electron microscopy, atom probe tomography, and crystal plasticity modeling.(c) 2022 Published by Elsevier B.V.
10.1016-j.jallcom.2022.167040	-1		In this paper, excellent performance W-Cu-Ni-Fe alloys with the addition of Ni and Fe (total content: 5 wt%) were successfully prepared by low temperature liquid-phase sintering, using the raw material of ultrafine W-Cu-Ni-Fe composite powder. Ultrafine W-Cu-Ni-Fe composite powder with high sintering activity and uniform composition distribution was prepared by a two-stage reduction method consisting of car-bothermal reaction and hydrogen deep deoxidation. Additions of Ni and Fe not only improved the wett-ability between W and Cu two phases, but also improved the bonding strength of two-phase interface. All sintered samples had higher relatively densities to ensure that the samples have great comprehensive properties. When Ni and Fe were co-added in appropriate proportions, the highest tensile strength and elongation of W-Cu-Ni-Fe alloy samples were 497 MPa and 9.12 % for the composition: W-3.5 wt%Ni-1.5 wt%Fe-25 wt%Cu, respectively. Meanwhile, with increasing Ni content from 0 wt% to 5 wt%, the compressive strength and failure strain of alloy samples increased from 1160 MPa to 2376 MPa and from 53 % to 98 %, respectively. In addition, with the enhancement of the solid solution strengthening effects of Ni and Fe on Cu matrix, the bending strength and microhardness of the alloy samples increased to 1174 MPa and 361 HV for composition: W-3.5 wt%Ni-1.5 wt%Fe-25 wt%Cu, respectively. Although the additions of Ni and Fe made the Cu matrix network structure have a uniform distribution, it led to a decrease in the electron transfer ability of the alloy, and thus, there was a decrease in electrical conductivity.
10.1016-j.jallcom.2022.167111	-1		It is always a great challenge to laser additive manufacture high-performance metal parts with high laser reflectivity, such as Cu based alloys, Al-Si based alloys and so on. In this work, the uniform thin Y2O3 coating was successfully introduced on the surface of the Cu-Cr-Zr powders by an in-situ chemical method. This Y2O3 coating can reduce the laser reflectivity of Cu-Cr-Zr powders without destroying their sphericity. The effect mechanism of Y2O3 on the microstructure, mechanical properties and electrical conductivity of CuCr-Zr specimens was further clarified. The grain size of the LPBF manufactured specimens is much smaller in case of Y2O3 doped Cu-Cr-Zr powder than that of the Cu-Cr-Zr powder. The Cu2CrZr(Y, O) nanoparticles with the size of similar to 50 nm form in the Cu matrix of Y2O3 doped Cu-Cr-Zr specimens, in addition to the Cr and Cu2CrZr precipitated particles. These Cu2CrZr and Cu2CrZr(Y, O) precipitated particles both exhibit a coherent interface with Cu matrix. Due to the refined grains and coherent second phase nanoparticles within grains mentioned above, the yield strength and ductility of Y2O3 doped Cu-Cr-Zr specimens are both improved significantly compared with the yield strength and ductility of undoped Cu-Cr-Zr specimens. Furthermore, the correlation between microstructure and properties of the Y2O3 doped Cu-Cr-Zr alloys manufactured by LPBF was also clarified. Our work provides a new strategy and in-depth view for the laser additive manufacturing of high-performance copper alloys and other alloys with high laser reflectivity.
10.1016-j.jallcom.2022.167192	6	grain; deformation; strain; strength; dislocation; cu-; tensile; size; ecap; grain size; sfe; ductility; hardening; high; stress	Due to the contradictory relationship between strength and toughness, many novel structures have been designed to overcome the tradeoff dilemma. In this paper, pure copper hetero grain composite laminates (HGCLs) composed of fine /coarse /fine grain bands were fabricated via rolling bonding and annealing. Microstructure characterizations indicated the grain size and hardness differences among different layers of HGCLs, and the interfaces were well bonded. When compared to the tensile results of the reference spe-cimen (non-composite laminates), it is clear that the well-bonded interface facilitated HGCLs to achieve ductility and strength beyond that anticipated by the rule of mixture. A series of loading-unloadin-g-reloading tests, quasi-in-situ EBSD and TEM tests were performed in order to explore the evolution of hetero-deformation induced (HDI) stress and dislocation of HGCLs, and the results demonstrated that mechanical incompatibility occurred during deformation and dislocation density at the interface was higher than the layer interior, resulting in a strain gradient. Additionally, the good ductility of HGCLs can be at-tributed to the coexistence of multiple factors, including annealing, slip bands, formation of deformation twins and stacking faults, and dislocation hardening. The findings provide a promising avenue for the design of a new generation metals with high-performance.
10.1016-j.jallcom.2022.167231	-1		High-speed rotation-induced hypergravity brings extra force to working alloys, which may change their diffusion behavior at metal-couple interfaces. Cu-Sn couples are conventionally used in the electronics industry, and their diffusion behavior is crucial for electronic safety. The diffusion behavior of the Cu-Sn couple was studied under thermal hypergravity induced by high-speed rotation, and its diffusion mechanism was revealed by advanced microscopy. The hypergravity in our Cu-Sn couple can be regarded as tension, and it suppresses the diffusion speed at 210 ? by a dramatically thick decrease in the Cu3Sn intermetallic phase.
10.1016-j.jallcom.2022.167307	3	sma; shape; shape memory; memory; smas; superelastic; bars; damping; cu-al-mn; mechanical; bending; applications; numerical; sma bars; material	Mechanical spectroscopy techniques and internal friction measurements have historically offered a key contribution to the understanding of fundamental mechanisms of defects mobility and phase transfor-mations in many kinds of materials. Nowadays, at the beginning of the millennium, the apparition of the new paradigm of nanotechnology reveals new unforeseen properties of the materials at the nano-scale. Nevertheless, instrumented nanoindentation appears as a new mechanical spectroscopy technique to ap-proach the measure of internal friction at the nano-scale through the direct evaluation of the loss factor eta. Indeed, nano compression tests on micro and nano pillars recently measured ultra-high mechanical damping in several Cu-based shape memory alloys (SMA). A step forward is given in the present work, approaching the design of potential micro dampers of SMA working in bending and torsion modes. Several micro devices were milled by focused ion beam (FIB) technique, on [001] oriented single crystals of a Cu-Al -Ni SMA. Ultra-high mechanical damping is demonstrated during superelastic bending of square section micro pillars by in-situ testing inside the scanning electron microscope, using a flat apex 60-conical in -denter in off-axis mode. Then, a series of micro beams and micro cantilevers were designed and milled by FIB, and tested using instrumented nanoindentation equipment by applying the load in bending mode as well as in a mixed bending-torsion mode during off-axis tests. In all cases, the internal friction, or me-chanical damping per cycle and per unit of volume, was calculated from the measured load-displacement curve. Superelastic cycling during bending of micro pillars, micro beams and micro cantilevers, exhibits stable and reproducible ultra-high mechanical damping with a loss factor eta > 0.1. These results paved the road for designing micro-dampers of Cu-based SMA, able to work in different mechanical modes of com-pression, bending and torsion, opening the way for many applications of mechanical damping at the nano-scale.(c) 2022 The Author(s). Published by Elsevier B.V. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/).
10.1016-j.jallcom.2022.167425	16	wear; composite; composites; powders; milling; particles; powder; wt; sliding; friction; hardness; matrix; mechanical; surface; properties	Copper alloys has excellent electrical conductivity and thermal stability. These properties may also relay on the manufacturing process which helps to enhance their mechanical strength . In this research, nano-mechanical properties of Laser Powder Bed Fusion (LPBF) Cu-Cr-Zr copper alloy was investigated to reveal the influence of Cu2O nano precipitates. The fabricated copper parts were inspected for their grain orientations and irregularities using Optical Microscopy (OM) and Field Emission Scanning Electron Microscopy (FESEM) with Energy Dispersive X-ray analysis (EDX). The printed copper alloy possesses polycrystalline grain structure with columnar and equiaxed grains along the build directions. The formed Cu2O nano precipitates were confirmed by the X-ray diffraction (XRD) and Transmission Electron Microscopy (TEM) and their grain orientations were assessed through Electron Backscatter Diffraction (EBSD) analysis. The homogenous distribution of precipitates formation was confirmed by the nano-hardness mapping and reduced elastic modulus mapping in which the indentation was performed in the specific area of 20 mu m x 20 mu m. The maximum nano-hardness of 1.05 GPa and maximum reduced elastic modulus of 137.6 GPa was obtained. Using the topographic wear tracks, the worn-out depth of 267.9 nm and 352.4 nm was witnessed in the nano-scratch and nano-wear test. Strain rate sensitivity of the copper alloy parts were also examined based on 3 different strain rates (3.3 x10-5, 1.6 x10-5 and 2.6 x10-4 s-1) and the results displays the negative strain rate behaviour of the printed copper alloy parts. The maximum Ultimate Tensile Strength (UTS) of about 340 +/- 6 MPa was observed in the strain rate of 3.3 x 10-5 s-1 and also the fracture morphology substantiated the ductile behaviour of the printed copper alloy parts by the occurrence of dimples and necking.
10.1016-j.jallcom.2022.167438	-1		This study investigates the damping properties of Cu-Al-Mn shape memory alloys (SMAs) with various chemical compositions and the effects of the addition of quaternary alloying elements Ag and Nb on the microstructure, martensitic transformation behavior, and damping capacity of SMAs. Compared to other Cu-12Al-xMn (x = 4-7 wt%) SMAs, Cu-12Al-5Mn has a more significant inherent and intrinsic internal friction (IFPT + IFI) peak above room temperature. The addition of Ag or Nb to Cu-12Al-5Mn reduced the grain size, thereby increasing the hardness of the alloys; however, the damping capacity and temperature of the IFPT + IFI peak decreased simultaneously. The addition of Ag to Cu-12Al-5Mn significantly reduced the damping capacity (IFPT+IF(I )peak) because of the notable decrease in the amount of transformed martensite. Moreover, the addition of Nb to Cu-12Al-5Mn caused the AlNb3 phase to precipitate, limiting the mobility of the martensite variant interfaces and slightly decreasing the damping capacity (IFPT + IFI peak). Among the Ag-and Nb-doped Cu-12Al-5Mn SMAs, Cu-12Al-5Mn-1 Nb showed not only a significantly higher hardness but also a higher IFPT + IFI peak, with tan delta exceeding 0.01 at approximately 50 ?.
10.1016-j.jallcom.2022.167447	-1		We report on the microstructure of Cu-La alloys, which is a candidate material for the electrode of fluoride -ion battery, prepared by the rapid solidification method. The Cu-La alloys near eutectic point (24.5at%La) were quenched at different cooling speed to obtain optimized lamellar microstructure. The cross-section of the Cu-24.5at%La alloy exhibited a lamellar microstructure, in which the Cu-rich and La-rich phases were well proportioned. A hexagonal Cu5La phase with a space group P6/mmm was confirmed in the Cu -en-riched areas, along with tetragonal Cu4La particles with an I4m 2 and hexagonal Cu2La with the P6/mmm. Furthermore, different cooling rate during solidification were applied by changing the wheel rotation speed of the device. The higher the rotation speed, the faster the cooling rate, and the finer the microstructure. The width of each layer in the microstructure was approximately 100 nm.
10.1016-j.jallcom.2022.167448	-1		The microstructure evolution, phase interface relationships, and corresponding hardness changes of dis-continuous precipitation in Cu-15Ni-8Sn alloy during the aging process were investigated. The samples were isothermally aged for 15 h at 500-700 degrees C to yield discontinuous precipitates with varying lamellar spacings. The results showed that discontinuous precipitation with a lamellar structure is composed of the alpha-Cu phase and gamma-DO3 phase, which has an incoherence interface and satisfies the K-S orientation re-lationship. With the increase of aging temperature, the lamellar spacing of the discontinuous precipitation increases, the length of lamellar shortens, and the lamellar nature weakens. Simultaneously, the dis-continuous coarsening reaction is accelerated. The addition of the trace Co element can inhibit the for-mation of discontinuous precipitation and discontinuous coarsening phase. Co enrichment was found in the gamma-DO3 phase, which can alter the lamellar spacing and then affect the hardness of the Cu-15Ni-0.5Co alloy. In addition, the hardness of discontinuous precipitation in the Cu-15Ni-8Sn-(0.5Co) alloy is negatively correlated with the lamellar spacing and can follow the Hall-Petch type relation.(c) 2022 Published by Elsevier B.V.
10.1016-j.jallcom.2022.167506	-1		A thermo-mechanical treatment was designed for a hypo-eutectic Cu-12Ag alloy in order to enhance its tensile strength, as high as 1189 MPa, at the relatively minimal cost of the electrical conductivity, as good as 71.9%IACS, the combination of strength and conductivity being far superior to other Cu-Ag alloys ever re-ported in the literature. To understand detailed mechanisms, a Cu-7Ag alloy and a Cu-12Ag alloy, which is beyond the maximum solubility (8 wt%) of Ag in Cu, were chosen for comparison and homogenized at 777 degrees C for an hour followed by aging at 400 celcius. The peak-aged alloys were then cold-rolled with a 99% reduction. Cu-7Ag showed higher hardness than that of Cu-12Ag at peak aging. However, Cu-12Ag showed higher strength and conductivity than those of Cu-7Ag after cold rolling. The elongated dispersed Ag phases in Cu-12Ag attributed extra strengthening, while keeping a minimal reduction of the conductivity after cold rolling.(c) 2022 The Author(s). Published by Elsevier B.V. This is an open access article under the CC BY license (http://creativecommons.org/licenses/by/4.0/).
10.1016-j.jallcom.2022.167676	-1		The discontinuous precipitation in a Cu-10Ni-1Si alloy aged at 500 degrees C and 550 degrees C was studied to clarify the types of discontinuous precipitates, and the crystal relationships between precipitates and the matrix. The continuous delta-Ni2Si precipitates were detected in the initial aging stage, then discontinuous beta-Ni3Si and continuous delta-Ni2Si precipitates were detected simultaneously. The crystal relationship between dis-continuous beta-Ni3Si precipitates and the copper matrix at the beginning of aging was that: (111)Cu//(111)beta, [011]Cu//[011]beta. The lamellar discontinuous beta-Ni3Si precipitates significantly improve stress relaxation re-sistance and damping properties, which are attributed to the interaction between lamellar structure and dislocation motion. These findings indicated that the formation of the lamellar discontinuous precipitates tends to prevent dislocation slip and promote precipitation, resulting in enhanced mechanical properties and conductivity properties simultaneously.
10.1016-j.jallcom.2022.167879	6	grain; deformation; strain; strength; dislocation; cu-; tensile; size; ecap; grain size; sfe; ductility; hardening; high; stress	Generally, two types of deformation textures of copper-type and brass-type textures are evolved in face -centered cubic (FCC) metals. During deformation, dislocation motion determines which texture will be dominant. The copper-type texture is formed in metals of high stacking fault energy by cross-slip of dis-locations and subsequent dislocation cell formation. On the other hand, deformation twinning involves the brass-type texture evolution, whereas some exceptions, such as Al-Mg alloys, also have been reported. This study examined deformation texture evolutions in four cold-rolled FCC alloys of pure Cu, Brass (Cu-37Zn), Al-6Mg, and Al-8Mg alloys. Electron backscattered diffraction and X-ray line profile analysis methods in-vestigated the deformation texture evolution. Three different strains of 0.25, 0.45, and 0.63 were applied to observe the strain effect on texture evolution. In pure Cu, the copper-type texture is developed, as com-monly known. The brass-type texture is developed in Brass and Al-Mg alloys. More reduction ratios in those alloys lead to the copper-type texture strengthening in pure Cu, whereas stronger brass-type texture is shown in Brass and Al-Mg alloys by applying more reduction. While the brass-type texture evolution in Brass can be illustrated by deformation twinning, deformation twins are absent in deformed Al-Mg alloys despite their evident brass-type texture formation. Instead, the short-range ordering (SRO) mechanism can explain the brass-texture evolution in Al-Mg alloys. Planar slips by the high Mg content of Al alloys strengthen the rotated Goss orientation with brass-type texture evolution after cold-rolling processes of those alloys.
10.1016-j.jallcom.2022.167938	-1		The magnetic property endows Cu-Fe alloy with huge application perspective in electromagnetic field. The pathway however to improve both segregation and magnetic property simultaneously remains unclear. In this work, we explore a method consisting of laser melting deposition (LMD) and third-element addition. As the Si element is introduced, the LMD-(Cu65Fe35)10Si immiscible composite shows a duplex micro-structure with the heterogeneous Fe3Si and alpha-Fe (Si) particles embedded inside epsilon-Cu matrix, resulting a low coercivity (7.03 Oe) and high saturation magnetization (29.0 emu/g). We further investigate the distribution of Fe-rich phase via the TiB2 particles as nucleating agent, the resulting LMD-((Cu65Fe35)10Si)2.5TiB2 composite shows a sandwich structure with greatly reduced defects and homogenous dispersed particles. The increased coercivity (28.2 Oe) and saturation magnetization (49.5 emu/g) are obtained, and the relevant mechanism regarding microstructure to magnetic property is revealed. This work offers a new possibility for tuning magnetic property of Cu-Fe alloy.
10.1016-j.jallcom.2022.167998	-1		Based on the deep undercooling rapid solidification method, the Cu based alloy has reached different un-dercooling degrees. The microstructure and evolution of non-equilibrium solidification of two alloys were systematically studied. It is found that grain refinement occurs in both the large undercooling range and the small undercooling range of the two alloys. EBSD technology was used to analyze the grain refinement structure, and the results showed that the grain refinement structure with large undercooling and that with small undercooling had completely different grain orientations. The grain refinement of low undercooling alloy is caused by dendrite remelting and fragmentation, while that of high undercooling alloy is completed by stress induced recrystallization. The evolution law of undercooling and microstructure hardness was systematically studied by using a microhardness tester. It was found that a sudden drop in grain size oc-curred near the critical undercooling, which is the direct evidence of grain refinement of non-equilibrium solidification structure of high undercooling alloy due to recrystallization.
10.1016-j.jallcom.2022.168121	-1		Composited with steel is a commonly used method to improve the strength and toughness of bearing materials. The Cu-x wt% Al/1010 steel (x = 0, 6, 7.5 and 9) bimetal laminated composites (BLCs) were fabricated by continuous solid/liquid bonding, and four well bonded and interface defect-free BLCs were obtained. The interfacial microstructure evolution and bonding mechanism were investigated in Cu-xAl/ 1010 steel BLCs with different Al contents. The results show that a straight metallurgically bonded interface is formed in pure Cu/1010 steel BLC, and a diffusion layer composed of Fe and Al appears on the side of the 1010 steel in Cu-7.5Al (C61000)/1010 and Cu-9Al (C61800)/1010 steel BLCs. In contrast, a transition layer of Cu-Al-Fe is formed in Cu-6Al (C60800)/1010 BLC due to the grain boundary diffusion. The tensile-shear test results show that the interfaces are always well bonded and fracture occurs on the Cu-xAl side after large deformation. The formation of this sufficiently strong interface is attributed to the diffusion layers and tight interatomic bonding between Cu and Fe. The tribology properties of the three Cu-Al alloys (C60800, C61000 and C61800) under different speed and load were also revealed. It is substantiated that the wear resistance increases with increasing the content of Al, and the wear mechanism changes from adhesive wear to abrasive wear due to the formation of beta'-AlCu3 phase. The results provide significant guidance for industrial preparation of bimetal laminated composites involving Al and Fe, and a necessary consideration for the study of lead-free bearing of Cu-Al alloy.
10.1016-j.jallcom.2022.168269	-1		The precipitation behavior and strengthening effects of the Cu-0.42Cr-0.16Co alloy aged at 450 degrees C was investigated using atom-probe tomography, transmission electron microscopy, and hardness and electrical conductivity measurements. The results showed that the fine FCC Cr-rich precipitates with a cube-on-cube orientation relationship (OR) were formed by Cr and Co enrichment at the early aging stage, semi-coherent with the Cu matrix. The OR transformation of the FCC Cr-rich precipitates from the cube-on-cube OR to the OR of (220)Cu//(220)Cr, [112]Cu//[110]Cr occurred with prolonging the aging time. The OR transformation decreased the mismatch degree along the [111]Cu and [112]Cu crystallographic directions and produced a strain difference along different crystallographic directions. Thus, some ellipsoid precipitates were formed in the Cu-Cr-Co alloy during aging. In the peak-aged stage (aged for 8 h), the aging strengthening of the CuCr-Co alloy was mainly attributed to the precipitation of the FCC Cr-rich particles, and the strengthening was controlled by the Orowan mechanism. The peak-aged alloy exhibited a larger size of precipitates than the alloy aged for 4 h, inducing a stronger precipitation strengthening effect (similar to 153 MPa).
10.1016-j.jallcom.2022.168281	15	aging; strength; conductivity; electrical conductivity; electrical; mpa; treatment; strengthening; degrees; cu-; cold; precipitation; tensile strength; tensile; iacs	In order to improve the strength and electrical conductivity of Cu-Ni-Si alloy, the columnar crystalline C70250 copper alloy strip suffer from two deep cryogenic rolling-aging treatments with large deformation, and the relationship between the cryogenic rolling-aging process and microscopic structure, mechanical, conductive properties is studied, and the precipitation behavior is analyzed. The research findings show that the columnar crystalline C70250 copper alloy produced by continuous directional solidification can be directly processed by two cryogenic rolling-aging treatment with large deformation, eliminating the tra-ditional solution treatment process and obtaining a fibrous tissue structures containing high-density dis-locations and multi-scale precipitates, the yield strength, tensile strength and electrical conductivity of the alloy reached 879 MPa, 923 MPa and 38.7 % IACS respectively, combination of strength and electrical conductivity is excellent. Two deep cryogenic rolling with large deformation can force the matrix to change to amorphous, favorable to atomic diffusion. Solute atoms are continuously transformed into Ni2Si phase and Cu atoms are continuously expelled, forming large-sized pure Ni2Si precipitated phase and small-sized NiSi cluster phase containing Cu atoms, which together impede dislocation movement and reinforce alloy. With the uniform precipitation of multi-scale nano-precipitation phases and reduction of grain boundary density, the electrical conductivity along the rolling direction is significantly reduced.
10.1016-j.jallcom.2022.168410	-1		The Cu-4Sn and Cu-4Sn-0.15P alloys with rod diameter of 12.5 mm were prepared and then cold drawn to 2.6 mm via multi-pass drawing. The microstructure evolutions, mechanical properties, and electrical conductivity of Cu-4Sn and Cu-4Sn-0.15P alloys were comprehensively analyzed using optical microscope, scanning electron microscope, tension test and electrical conductivity tester. As compared with the P-free alloy, the addition of P can form a new kind of P-rich phase in the Cu-4Sn alloy, and thus refine the casting microstructure via pinning the grain boundary. The toughening mechanisms of P-rich phases in Cu-4Sn-P alloy wires during cold drawing were investigated. With accumulative drawing strain, the spherical P-rich phase gradually changes into fibrous phases, which thus introduce obvious fiber reinforced strengthening. In addition, the distribution of P-rich phase also enhances the < 111 > texture, and promotes the growth of fragmentation zone. It contributes to an improved ultimate tensile strength and final elongation from 664.5 MPa and similar to 0 % in Cu-4Sn alloy to 970.5 MPa and 1.53 % in Cu-4Sn-0.15P alloy. Finally, the conductivity for Cu-4Sn-0.15P decreases slightly owing to the intensified electron scattering with high amount of pri-mary phase after the addition of P element.
10.1016-j.jallcom.2022.168658	15	aging; strength; conductivity; electrical conductivity; electrical; mpa; treatment; strengthening; degrees; cu-; cold; precipitation; tensile strength; tensile; iacs	The Cu-11Al-3Ni-2.5Mn-1Y alloy prepared by hot-press sintering was subjected to aging treatment at dif-ferent temperatures of 350 degrees C, 400 degrees C, 450 degrees C, 500 degrees C and 550 degrees C, respectively. The phase composition, microstructure, mechanical and damping properties were characterized. The results show that the alloys after the ageing treatment are mainly composed of 18 R martensite and 2 H martensite. The precipitation phase begins to appear and the best comprehensive properties are obtained at the aging temperature of 450 degrees C. The hardness and strength values reached 347.6 HV and 642.6 MPa, respectively. The strengthening mechanisms are mainly involved in lattice distortion and dislocation increment effect caused by solution strengthening, shearing and hindering effect of precipitated phases and dislocations, fine grain strength-ening effect caused by grain size reduction, and the increase of large angle grain boundary. Simultaneously, the room temperature damping reached 0.0723, which is 93 % higher than the original sample of 0.38. The improvement of damping properties is closely related to the changes in the number and size of martensite, the interfacial damping effect caused by precipitated phases, and the pinning and unpinning reaction be-tween dislocations and precipitated phases. Therefore, alloys with both high mechanical and high damping properties can be obtained by proper aging treatment. In addition, the increase in phase transition tem-perature of high temperature damping properties also provides some guidance for the exploration and development of this alloy in the high temperature field.
10.1016-j.jallcom.2023.168820	2	corrosion; surface; film; electrochemical; films; spectroscopy; layer; current; solution; potential; resistance; composition; x-ray; ions; showed	Marine biofouling is a critical issue that seriously deteriorates the service performance of marine infra-structure. It is a big challenge to develop environmental-friendly materials for long-term marine anti-fouling. Herein, we have proposed the utilization of high-speed laser cladding technology to fabricate copper-iron alloy capable of self-grown microchannel through dealloying process in a marine corrosive environment, which could effectively store copper ions. The phase composition and microstructure evo-lution were characterized and analyzed by scanning electron microscopy. Corrosion mechanism of deal-loying and distribution of microchannel was investigated. After being immersed for 2 months, the samples can form a de-ironized microchannel layer with a thickness of 350 mu m, which reduces the bonding strength between corrosion products and the surface, thereby promoting the flacking of the corrosion products. The self-grown microchannel could store the copper ions which will solve the problem that the antifouling effect of traditional copper alloys decreases during long-term seawater immersion. These results may guide the advanced design of new promising antifouling materials with environmental-friendly, durable, and remarkable antifouling capability for different practical requirements in marine engineering.
10.1016-j.jallcom.2023.168865	-1		This study investigated the microstructure and precipitation sequence of the Cu-3Ti-1Cr (wt%) alloy using optical microscopy, transmission electron microscopy (TEM), and high-resolution TEM and studied its strengthening mechanism. The precipitation sequence of Cu-3Ti-1Cr aged at 500 degrees C was a supersaturated solid solution -> spinodal decomposition ->beta'-Cu4Ti phase with a tetragonal structure. Additionally, the orientation relationship between the Cu matrix and coherent beta'-Cu4Ti precipitates were [001]Cu//[001]beta' and (100)Cu//(130)beta' at the peak aging time. Upon extending the aging time, the growth rate of the beta'-Cu4Ti precipitates followed the Ostwald ripening law. The Cr element mainly exists in the forms of a coarse Cr phase, a TiCr2 phase, and as nanoscale Cr precipitates in the matrix. This plays an important role in inhibiting discontinuous precipitation and ensuring the stability of properties. With an increase in the aging time, the hardness increased initially and then decreased slightly after 2 h, thereby indicating over-aging. Precipitation strengthening was the major factor contributing to the high strength of the Cu-3Ti-1Cr alloy. (c) 2023 Published by Elsevier B.V.
10.1016-j.jallcom.2023.169033	-1		Thermal-mechanical treatment is critical for the synthesis of Cu-Ni-Si alloys with high strength and con-ductivity. In this work, a high-temperature/short-time pre-aging treatment (600 degrees C, 10 min) was introduced to the thermomechanical processes of Cu-Ni-Si alloys, and the effects of pre-aging on the microstructure and properties of the alloy were investigated in detail. The results showed that Ni2Si particles precipitated from the matrix during pre-aging, promoting the formation of a nanoscale microstructure after cold rolling (cold rolled by 85% reduction). The pre-precipitated Ni2Si particles that formed during pre-aging consumed part of the dissolved Ni and Si solutes in the copper matrix, resulting in a higher initial conductivity before the final aging process. The grain refinement effect and high deformation-stored energy benefited the subsequent final aging by lowering the aging temperature and improving the alloys' high performance. This provided a guideline for the design and development of high-strength, high-conductivity copper alloys. The strengthening mechanism and corresponding microstructure evolution are also systematically investigated. The pre-existing Ni2Si particles strongly hinder the mobility of dislocations during cold rolling and retard the recovery of sub-structures at room temperature, leading the grain refinement in the nanoscale.
10.1016-j.jallcom.2023.169569	-1		Prolonged aging of Cu-Ni-Si alloy induced the formation of discontinuous precipitates (DPs) of fiber-shaped Ni2Si intermetallic compounds, rendering good conductivity and relatively inferior strength . To improve the strength of Cu-Ni-Si alloy with DPs, groove-rolling technique was utilized to plastically deform the aged Cu-6Ni-1.5Si specimen. As the rate of area reduction increased from 20% to 50% and 80%, the diameter and interspacing of Ni2Si fibers decreased. Both tensile strength and fatigue limit stress, which are essential for the design of electrical and electronic mechanical components, of Cu-6Ni-1.5Si specimen increased sig-nificantly with groove-rolling. It was suggested that an extra strengthening was achieved by Ni2Si fiber reinforcement in addition to work hardening. The increase in yield strength by fiber reinforcement was estimated by Orowan strengthening principle, assuming ideal fiber arrangement. The estimated yield strength based on Orowan mechanism was found to be much greater than the experimentally measured value. This was because actual morphology and arrangement of fibers were largely different from the ideal state, necessitating an error factor, k, which varied with the true strain, epsilon t, due to groove-rolling. The k showed initial steep increase and subsequent mild increase to epsilon t, followed by decreasing trend after epsilon t approximately equal to or the image of 0.7. The physical background of enhanced fatigue strength of rolled specimen was discussed based on the detailed microstructural observation on crack initiation and propagation behavior.
10.1016-j.jallcom.2023.169619	-1		First-principles calculations and experimental studies, including transmission electron microscopy (TEM), electrical conductivity measurements, and yield strength and stress relaxation resistance tests, were carried out to determine the influence mechanism of trace Si on the precipitates and stress relaxation resistance of a Cu-Cr alloy. TEM observation and aging precipitation kinetic analysis showed that the addition of trace Si significantly refined the Cr-rich precipitates of the Cu-Cr alloy but did not appreciably promote the nu-cleation of the precipitated phase. The influence of trace Si on the Cr-rich precipitates was assessed in terms of the Si-Cr and Si-vacancy interactions. The first-principles calculations reveal that there exists a strong attraction between Si and Cr with an interaction energy of-0.27 eV for the nearest neighbor, which could promote the formation of Si-Cr clusters in the early aging stage that serve as heterogeneous nucleation particles for precipitates and induce the refinement of body-centered cubic (bcc) Cr-rich precipitates, re-sulting in an increase in the yield strength of the Cu-Cr alloy. The strengthening precipitates of the Cu-Cr-Si alloy mainly consisted of fcc Cr-rich precipitates and bcc Cr-rich precipitates, the strengthening mechanisms of which were the dislocation shear mechanism and dislocation bypass mechanism, respectively. In terms of performance, the conductivity of the Cu-Cr alloy decreased with the addition of trace Si from 94.5% IACS to 92.5% IACS, the yield strength increased from 178 MPa to 193 MPa, and the stress relaxation rate de-creased from 18.93% to 15.27%. The improvement in the stress relaxation resistance of the Cu-Cr alloy with the addition of trace Si was mainly attributed to the drag effect of the element on dislocation movement and the refinement effect of the element on Cr-rich precipitates.
10.1016-j.jallcom.2023.169644	-1		The effect of B addition on microstructures and properties of as-cast, solution-treated and aged Cu-15Ni-8Sn alloy was systematically investigated in the present study. It is found that the micron-scale Ni6.67SnB2 phase is identified in as-cast microstructure for B-containing Cu-15Ni-8Sn-xB alloys. Moreover, it is sug-gested the segregation of Sn element at grain boundary could be alleviated to a certain degree with B addition. After being solution-treated at 850 degrees C for 4 h, the Ni6.67SnB2 phase is still existed in the matrix, thereby resulting in a significant influence on the microstructures and properties during subsequent aging process. Results demonstrate that, during aging treatment at 400 degrees C, the transformation of DO22 ordered phase into γ′ ordered phase can be increasingly inhibited with increase of B content and completely prevented for 0.3 and 0.5 wt% B addition. Additionally, the appropriate B addition (0.04, 0.08, 0.1 wt%) could remarkably suppress the formation and growth of the discontinuous precipitation. Nevertheless, with ex-cess B addition (0.3, 0.5 wt%), the discontinuous precipitation is instead promoted. More importantly, alloys with appropriate B addition (0.04, 0.08, 0.1 wt%) could also maintain the peak hardness without dete-rioration as long as 18 h during the aging process, which suggests the tremendous enhancement of soft-ening resistance. It is believed that the suppression of discontinuous precipitation by Ni6.67SnB2 phase should be responsible for such enhancement of softening resistance. It is anticipated that the current work could provide guidance for the multi-component design of high-performance Cu-Ni-Sn alloy.
10.1016-j.jallcom.2023.169751	4	transformation; martensite; martensitic; phase; shape; beta; memory; shape memory; temperature; temperatures; martensitic transformation; gamma; transformation temperatures; effect; thermal	A new interpretation of factors controlling the kinetics of reverse transformation of martensites stabilized by prestrain is suggested. We investigate the effect of amount of prestrain in the beta(1)' martensite and in the beta-phase on temperature and kinetics of the reverse martensitic transformation in Cu-Al-Ni shape memory alloy single crystals. Calorimetry and video recording of the jumping samples, provoked by the burst strain recovery during temperature-induced reverse transformation, are used in experiments. For crystals deformed both in the beta(1)' martensite and in the beta-phase, we report the existence of a sharp transition (crossover) from the mechanical stabilization of martensite to the burst reverse martensitic transformation which proceeds as a single avalanche. The crossover occurs for prestrain values close to the maximum transformation strain. The specific energy of the jump during burst strain recovery depends on the maximum stress applied during prestraining the sample. The crossover from a broad transformation range to an infinite or spanning avalanche is predicted by 3D random field Ising model for disordered systems undergoing the first order phase transition. Based on this model, we explain the crossover in deformed Cu-AlNi crystals by a rapid decrease of structural disorder towards the critical one at the final stage of the formation of detwinned gamma(1)' martensite. A simple solution is obtained for the critical transformation rate which produces jumping of the sample during burst reverse transformation after prestrain.
10.1016-j.jallcom.2023.169988	2	corrosion; surface; film; electrochemical; films; spectroscopy; layer; current; solution; potential; resistance; composition; x-ray; ions; showed	In this work, preparation of Cu-Ni/Nano-Al2O3 composite coating with (111)-preferred orientation on the surface of the H64 brass via electrodeposition technique. Variation of the deposition current density was found to play a key role in the control of the microstructure and strongly influence the corrosion resistance of the composite coating. Electrochemical impedance spectroscopy results indicated that the increase of nano-alumina content in composite coating is caused by the change of polarization mode. Under different current densities, the Ni (111) plane is only preferred orientation and the relative texture coefficient reaches the highest value of 54.36% at 5 A center dot dm-2. The crystallite size of these coatings is about 10-55 nm dependent on current density, and high current density could refine the size. The microstructure of the coating changed from cauliflower to spherical with increasing deposition current density. Moreover, the Cu-Ni/ Nano-Al2O3 composite coating obtained at 5 A center dot dm-2 increased the polarization resistance and coating re-sistance of the H64 brass by about 50% and 83%, respectively. The corrosion potential (Ecorr) of Cu-Ni/Nano-Al2O3 composite coating is shifted towards the nobler direction from-1.191 V to-0.063 V(Ag/AgCl) with the current density increases. The corrosion mechanism of Cu-Ni/Nano-Al2O3 composite coating has gone through two stages corresponding to two-time and three-time constant of EEC models, respectively. The Cu-Ni/Nano-Al2O3 has large potential merits in field of corrosion.
10.1016-j.jallcom.2023.170276	12	thermodynamic; ternary; phase; data; experimental; equilibria; phase equilibria; liquid; binary; experimental data; calculated; phases; literature; model; calphad	The binary Cu-Sm system is one of the basic sub-systems, necessary for the development of the materials used as permanent magnets. Nonetheless, there can be found numerous inconsistencies in the phase equilibria data for the system. The current work deals with the evaluation of the phase stabilities of the intermetallic phases in the system and phase equilibria in the Cu-Sm system with the DTA, SEM/EPMA and XRD methods. Cu6Sm and Cu5Sm have been found to express some homogeneity ranges. It was confirmed that CuSm is forming by a peritectic reaction, rather than by congruent melting. The updated phase equilibria data was summed up in a new version of the Cu-Sm phase diagram. The hardness of the Cu6Sm phase was found to be 335 +/- 29 HV.
10.1016-j.jallcom.2023.170380	-1		Oxide dispersion strengthened copper-based material is widely used in electrical contact materials due to its excellent mechanical and electrical properties. However, researchers have found that large Y2O3 particles have poor interfacial bonding with the copper matrix in the study of oxide dispersion strengthened copper. In this work, Y4Zr3O12 nanoparticles were successfully prepared through solid-liquid doping and directly added into oxide dispersion-strengthened copper by mechanical alloying. A scanning electron microscope, a transmission electron microscope, an X-ray diffractometer, and electrical and mechanical tests were used to characterize the microstructure and performance of composite materials. The interfaces between the Y2O3/ Y4Zr3O12 nanoparticles and Cu were systematically studied. The interface bonding between Y4Zr3O12 and Cu was better than that of Y2O3 and Cu. The effect of different Y4Zr3O12 contents (1, 3, and 5 wt%) on the microstructure and mechanical properties of the composites was studied. Results showed that the Cu-3 wt% Y4Zr3O12 composites exhibited the best comprehensive properties. The Vickers hardness, yield strength, ultimate tensile strength, maximum engineering strain, and electrical conductivity of the Cu-3 wt% Y4Zr3O12 composites were 132HV, 203.5 MPa, 284.7 MPa, 15.8 %, and 90.3 % International Annealed Copper Standard, respectively. & COPY; 2023 Elsevier B.V. All rights reserved.
10.1016-j.jallcom.2023.170402	-1		An economical and practical thermomechanical process that is able to achieve a good combination of strength and conductivity is highly desired for the copper alloys. Here, a new multi-stage thermo-mechanical treatment, characterized by a pre-rolling with small strain followed by a short-time aging before the secondary rolling and aging, is implemented in the Cu-Cr-Zr alloys. Its effect on the mechanical and electrical properties of the alloy is investigated, as well as the mechanism for improving the properties. Strength and ductility are improved at the expense of only a little electrical conductivity compared to those alloys that have undergone conventional single-stage thermomechanical treatment. The pre-rolling and pre-aging result in dense, dispersive and stable shear bands, which contain lots of dislocations and fine grains. Dislocation strengthening is the main reason for the increased yield strength, while heterostructure consisting of microstructures inside and outside the shear bands gives the processed alloys good tensile plasticity. Our studies shed some lights on development of a short and cost saving thermomechanical process for the Cu-Cr-Zr alloys.
10.1016-j.jallcom.2023.170618	-1		Crystallization behavior of a Cu58Y37Sc5 metallic glassy alloy was studied on heating and on room -tem-perature deformation by different methods. At first, phase transformations were studied by differential scanning and isothermal calorimetries. X-ray diffractometry studies indicated simultaneous formation of the Cu2Y, CuY and CuSc crystalline phases which is the characteristic of a eutectic crystallization while the isothermal crystallization kinetics rather corresponded to primary crystallization. Moreover, transmission electron microscopy observations revealed a remarkable complexity of this crystallization process including heterogeneous nucleation on pre-existing particles. & COPY; 2023 Elsevier B.V. All rights reserved.
10.1016-j.jallcom.2023.170707	3	sma; shape; shape memory; memory; smas; superelastic; bars; damping; cu-al-mn; mechanical; bending; applications; numerical; sma bars; material	The main characteristic feature of Cu-based high-temperature shape memory alloys (SMAs) such as Cu-Al-Ni alloys is their high transformation temperatures that enable their applications at high temperatures. The improvement of thermodynamic properties of SMAs with reinforcements is essential for more applications at high temperatures with fewer negative effects of exposure at high temperatures, such as alloy softening that can deteriorate the strength and shape memory effect (SME) simultaneously. To avoid the negative effects of micro-reinforcements such as stress localization, in this study, graphene (GN) was substituted with Ni, and a new alloy labeled Cu-Al-GN with 0.2 wt% graphene was formed. A graphene-reinforced alloy labeled Cu-Al-Ni-GN was also fabricated by a laser powder bed fusion process for comparison purposes. The results showed that the Cu-Al-GN alloy exhibited enhanced performance in terms of improved reinforcement distribution, finer grains, defect-free samples with the highest SME at subsequent cycles, and less time required to achieve a targeted SME during heating, despite the smaller SME in the initial recovery cycles. Thus, the results of this study confirm that the proposed Cu-Al-0.2GN alloy combination promises high performance for recovery cycles and is time and cost saving, rendering it a suitable candidate for rapid production.& COPY; 2023 Elsevier B.V. All rights reserved.
10.1016-j.jallcom.2023.170797	-1		CuCr alloy with Cr contents of 50 wt% was synthesized in-situ by aluminothermic reduction under mag-netic/temperature coupling, and the uniformity of the microstructure and its regulation were studied. The effect of different slagging coefficients on the composition and microstructure uniformity of the alloy was investigated. The microstructural evolution of the alloy and the effects of heat treatment on the micro-structure and properties (conductivity and hardness) of as-cast CuCr50 alloys were researched. The results showed that when n(CaO/Al2O3)= 0.2, the microstructure of the alloy is uniform, the Cr-rich phase solidifies rapidly under the coupling field, and the grains can be refined to 25 pm. The supersaturated solid solution with a Cr solution of 2.44 % is produced in the matrix. After heat treatment, the Cr particles are refined to 20 pm and the microstructure tends to exhibit uniform growth . The supersaturated phase was precipitated, and the solid solubility of Cr is reduced to 1.27 %. The hardness increased by 15.43 % (87.5 HB to 101 HB) and the electrical conductivity increased by 1.46 times (13.82 MS/m to 20.03 MS/m). This method is expected to provide an effective method for the preparation of Cu-based immiscible alloys.& COPY; 2023 Published by Elsevier B.V.
10.1016-j.jallcom.2023.171014	16	wear; composite; composites; powders; milling; particles; powder; wt; sliding; friction; hardness; matrix; mechanical; surface; properties	In-situ Cu/NbC, Cu/NbC-WxC, and Cu/ WxC nanocomposites were synthesized by mechanical alloying (MA) at room temperature using high-purity premixed Cu(10-x)NbxW (x = 0, 5, 10 at%) elemental powders. The synthesized powders were then consolidated through Equal Channel Angular Pressing at 700 & DEG;C. The mi-crostructure, phase constituent, and hardness of the as-milled and consolidated powders were investigated using scanning and transmission electron microscopy, X-ray diffraction, and microhardness measurements. The 80 h MA resulted in the formation of a Cu/NbC and Cu/NbC-W nanocomposite powder with an average copper matrix crystallite size of 8-11 nm and NbC and W particle sizes mainly less than 100 nm. Refinement of the powders was achieved through cracking at the work-hardened areas in the copper matrix and fracturing of the tungsten and niobium particles. During consolidation, the W converted into W2C and WC phases. Additionally, the Cu matrix crystallite size increased to 41 nm, 43.6 nm, and 65.3 nm for Cu10Nb, Cu5Nb5W, and Cu10W, respectively. While Cu10Nb showed the highest hardness among the as-milled samples, Cu5Nb5W attained the highest hardness value of 462 HV after consolidation, which is due to its smaller Cu matrix crystallite size and finer carbide particles compared to the Cu10Nb and Cu10W alloys and likely due to the synergistic strengthening effect of the NbC and WxC carbide particles. These findings demonstrate the successful synthesis of in-situ Cu-based nanocomposites with tailored microstructures and constituent phases through mechanical alloying. & COPY; 2023 Elsevier B.V. All rights reserved.
10.1016-j.jallcom.2023.171029	-1		The Cu-based shape-memory alloy 81Cu-11Al-3Ni-3Mn (wt%) was processed by selective laser melting (SLM) and the parameters were optimized to obtain samples with a high relative density of up to 99 %. The study used ball milling of elemental powders to obtain the feedstock material and the process was de-veloped for building dense SMA structures. The process optimization is performed to obtain dense struc-tures by varying laser power and scan speed. Further, the parameters yielding higher density is selected to study the influence of the different laser power on the overall density, defect distribution, mechanical properties, and grain sizes. Cu-based SMA fabricated at different laser powers were characterized using Scanning electron microscopy (SEM), Differential scanning calorimetry, X-ray diffraction (XRD), tensile test, and microhardness tests. It was observed that the processing technique has a strong influence on the degree of porosity and the distribution of the pores, the grain size as well as the grain morphology. Dense and uniform samples are formed with elemental powder which shows a maximum hardness of 380 HV, and tensile strength of 1550 MPa. The transformation peak became sharp with respect to laser power increment and the transformation temperature increased with an increase in laser power. The study provides a path toward the deployment of SLM for building dense Cu-based SMA from elemental powders.& COPY; 2023 Elsevier B.V. All rights reserved.
10.1016-j.jallcom.2023.171033	-1		In this study, we investigated the color transition mechanism of Cu-5Al-5Zn-1Sn (in wt%) alloy during coldrolling and annealing processing by analyzing the correlation between microstructural characteristics and optical transition behavior. Single-phase Cu alloys have limited solubility which restrict on controlling their optical properties. Therefore, we propose a novel strategy for modulating the optical properties of singlephase Cu alloys. Cu alloys with low stacking fault energy (SFE) exhibit highly dense twin defects and dislocations when subjected to severe plastic deformation. In addition, annealed low SFE samples contain unique grain boundary structure, with different energies according to atomic structure and misorientation angle, which influences the density of states and electronic structure of the alloys. Consequently, the optical transition energy of the samples is affected by the grain boundary energy, which this influence to the chromaticity of the samples. These findings provide a new approach for adjusting the color of the alloys.& COPY; 2023 Elsevier B.V. All rights reserved.
10.1016-j.jallcom.2023.171202	0	solidification; phase; magnetic; magnetic field; undercooling; field; liquid; separation; peritectic; immiscible; cu-; dendrite; phase separation; microstructure; primary	The competitive phase selection during cooling a metastable alloy is mainly controlled by the process of nucleation and growth for either the equilibrium stable phase or metastable phase. However, the control of competitive phase selection is still a standing challenge. In this work, a general method for controlling the competitive phase selection process by in-situ forming nanoparticles is reported. The solidification experiments of Cu-Cr metastable immiscible alloys were performed to probe the effect of in-situ TiB2, Cr3C2/Cr7C3 or TiC nanoparticles. The results indicate that the Cr-rich minority phase originates from the liquid-solid phase transformation and exhibits coarse dendrite morphology for the Cu-Cr alloy without nanoparticles. In contrast, suitable nanoparticles may lower the Gibbs free energy barrier for the formation of metastable phase, trigger the liquid-liquid phase transformation, thus the Cr-rich minority phase almost shows spherical morphology and the size is only a few microns, even hundreds of nanometers. Furthermore, the microhardness of Cu-Cr alloys with nanoparticles is improved significantly. This strategy may have extensive application prospects for the modification of phase selection behaviors and solidification process of Cu-Cr metastable immiscible alloy.
10.1016-j.jallcom.2023.171319	-1		To reduce the oxygen content on the surface of alumina dispersion-strengthened copper alloy powders, and improve properties of the deposits prepared by cold spray additive manufacturing, these powders were pretreated with hydrogen reduction treatment at 300 & DEG;C and 500 & DEG;C, respectively. The microstructure and mechanical and electrical properties of the deposits before and after powder heat treatment were systematically researched. The results show that hydrogen reduction treatment can effectively reduce the oxide film on the surface of the alumina-dispersion-strengthened copper powder without changing the microstructure and mechanical properties of the powder. The alumina-dispersion-strengthened copper alloy deposit prepared from the as-received powder has obvious pores, and the tensile strength and electrical conductivity are 75 MPa and 38% IACS, while these deposits prepared from the powder treated at 300 & DEG;C and 500 & DEG;C present a dense microstructure. The tensile strengths and electrical conductivity are 202 MPa under 45% IACS and 245 MPa under 48% IACS, respectively. At the same time, the nano-Al2O3 particles are very stable under the heating and deformation conditions of adiabatic shearing by cold spraying, and the Al2O3 particles are not significantly broken during the severe plastic deformation caused by the high-speed impact of cold spraying, which enables the deposits to directly inherit the nano-dispersion strengthening structure of the powder. Therefore, it is effective to improve the mechanical and electrical properties of alumina dispersion-strengthened copper deposits by using hydrogen reduction pre-treatment to reduce the oxide film on the surfaces of the particles.
10.1016-j.jallcom.2023.171383	-1		The evolution of the dislocation density, precipitates, texture, and residual stress in lead-frame Cu-2.13Fe-0.026 P (wt%) alloys were studied. All samples showed residual compressive stress. Moreover, the dislocation density and residual stress of the rolled sample are higher than those of the annealed sample. After annealing, the sample is mainly composed of restored grains, and the dislocation density not generated an order of magnitude decrease. This trend may be the reason why the residual stress still exists in the sample after annealing. In addition, the presence of pits around Fe3P particles may contribute to the generation of the residual stress. More importantly, the texture type of each sample is mainly Brass (011)< 211 > , S (123)< 634 > or Copper (112)< 111 > , and the recrystallized Cube (001)< 100 > texture is rarely found. Finally, the structural energy density (Ev) of different textures is calculated. It was found that the Ev of the Copper (112)< 111 > texture affects the variation of its volume fraction, thereby controlling the evolution of the residual stress.
10.1016-j.jallcom.2023.171540	-1		The Cu-10Fe-based composites with different Nb content were fabricated by vacuum mold casting. The effect of Nb content on the solidification behavior and microstructure was investigated systematically and the optimal composition was determined as Cu-10Fe-1.0 Nb (wt%). The as-cast samples were rolled by 90% reduction at room and then aged at 250 celcius for different time. The properties results showed that, after aging for 1800 min, microhardness, tensile strength and elongation of the Cu-10Fe-1.0 Nb samples reached 145 HV, 553 MPa and 21.5%, respectively. The microstructure results showed that the primary Fe-rich phases in the Cu-10Fe-1.0 Nb samples were significantly refined due to the heterogeneous nucleation induced by Fe2Nb phases, and then led to the refinement of the matrix. The enhanced mechanical properties could be attributed to the Orowan strengthening, refinement strengthening and work hardening resulted from the numerous submicron-/nano-sized Fe particles, fine sub-grains and high-density dislocation in the matrix formed during thermo-mechanical treatment.
10.1016-j.jallcom.2023.171786	-1		Heat treatments have a significant effect on the properties of CuCrZr alloy. However, the mechanism of how heat treatments affect the microstructure and properties of CuCrZr alloy remain unclear during wire arc additive manufacturing (WAAM). Achieving the preparation of CuCrZr alloy with excellent performance by WAAM presents a challenging task. This study investigated the evolution of the microstructure, mechanical properties, electrical and thermal conductivities of CuCrZr alloy specimens fabricated by WAAM under different heat treatments. Microscopic analysis results illustrate that the specific heat treatments do not lead to significant changes in grain morphology, but can affect the formation of precipitation in CuCrZr alloy. The coarse Cr pre-cipitation is observed in the specimens of as-built (AB) and direct age hardening (DAH). Conversely, the solution annealing (SA) and solution annealing + age hardening (SAAH) specimens exhibit a uniform distribution of Cr elements without coarse Cr precipitation. Notably, in the SAAH specimen, the relationship between precipitated Cr and Cu matrix follows the K-S relationship: (111)Cu//(110)Cr, [110]Cu//[111]Cr, leading to a significant improvement in mechanical properties. The SAAH specimen demonstrates the best performance among all the specimens. It exhibits the an ultimate tensile strength of 301 & PLUSMN; 5 MPa, the highest hardness of 119.5 & PLUSMN; 2.4 HV, electrical conductivities of 45.8 & PLUSMN; 0.1MS/m and thermal conductivities of 309.2 & PLUSMN; 2.0 W/mK. This superior performance can be attributed to the combination of minimal lattice distortion and uniformly fine Cr precipi-tation in the SAAH specimen.
10.1016-j.jallcom.2023.171962	-1		With the development of flexible optoelectronic devices, the research on electrode materials with high conductivity and excellent contact characteristics has received extensive attention. In this study, we successfully prepared Ag-doped Cu-Cr-Zr alloy electrode film by co-sputtering deposition on the glass and PI (polyimide) substrates, respectively. The study aimed to investigate the effect of Ag on the performance of Cu-Cr-Zr alloy electrode film for flexible optoelectronic applications. The results showed that Ag promoted the growth of the film in the direction of {111} crystal plane group and promoted the growth of more prominent grain. Moreover, doped Ag can reduce the porosity of the film. Thus, the resistivity of the film reduced from 3.18 mu omega center dot cm to 2.32 mu omega center dot cm after Ag doping. The flexible bending performance of the film was optimized, with the film's resistivity of the film increasing only 5.6% after 20k bending. Furthermore, the film retained high adhesion strength, rating 4B on the glass substrate and 5B on the PI substrate. The root mean square of the film with a thickness of about 200 nm was less than 1.3 nm which means that the alloy film had good surface morphology. The Ag-doped Cu-Cr-Zr alloy electrode film is expected to have potential applications in flexible optoelectronic devices due to its high conductivity, excellent surface, and optimized flexible bending performance. In conclusion, the Ag-doped Cu-CrZr alloy electrode film prepared in this study is a promising candidate for flexible optoelectronic applications.
10.1016-j.jallcom.2023.171974	6	grain; deformation; strain; strength; dislocation; cu-; tensile; size; ecap; grain size; sfe; ductility; hardening; high; stress	The generation of a high density of twins few tens nanometers in size can enhance both strength and ductility. The present work aims to produce highly twinned microstructure in Cu-6 wt% Zn alloy of a moderate stacking fault energy (SFE) by equal channel angular pressing (ECAP) using a die with angles phi = 110 degrees and psi = 0. X ray diffraction (XRD) shows that a high density of defects is stored up to 2 passes then a recovery takes place. EBSD imaging reveals a high density of twins and a fibrous microstructure. Grains close to 100 nm in size are formed. Strain rate sensitivity (SRS) was investigated in compression and nanoindentation (NI). Compression curves show that deformation occurs by slipping with a contribution of twins to hardening. A high contribution of shear bands was revealed during ECAP and compression tests. The activation volume V* in compression and NI is in the range 70b3-100b3, consistent with the emission of dislocations from grain boundaries and twin boundaries The experimental values of V* were compared to those expected from defect densities.
10.1016-j.jallcom.2023.172018	-1		Investigating the diffusion behavior of binary system is crucial for understanding the solid-state diffusion in metallic joints, as it affects the interfacial reaction that forms intermetallic components (IMCs) and introduces Kirkendall voids that change the interfacial microstructures. In this study, we intuitively investigated the interfacial diffusion behavior of Copper-Zinc alloy binary interface by in situ transmission electron microscopy. Our findings revealed the interfacial diffusion of atoms, the growth processes of intermetallic phases, and the evolution of the Kirkendall voids during thermal diffusion. We observed that the Zn atoms diffuse rapidly into Cu and form the 13 phase at the onset of thermal diffusion at 200 & DEG;C. Additionally, with increasing temperature, Cu atoms control the diffusion and the formation of IMCs due to their higher diffusion coefficient in the 13 and & alpha; phases, which are 2.09 & PLUSMN; 0.63 x 10-16 m2/s at 250 & DEG;C and 3.44 & PLUSMN; 0.44 x 10-17 m2/s at 300 & DEG;C, respectively. Furthermore, we found that the interface significantly influences the interdiffusion rates of the IMCs and the formation of Kirkendall voids. The emergence of voids, which are formed at the initial defective site and the IMC layer at the temperature of 250 and 300 & DEG;C, respectively, leading to a considerable decrease in interdiffusion at the binary interface of two orders of magnitude in comparison to unaffected regions. Moreover, we revealed the evolution of Kirkendall void, involving the formation and merging of holes, as well as the gradual thinning of atomic layers during diffusion. These findings are essential for understanding the formation and evolution of IMCs and Kirkendall void in binary interfaces.
10.1016-j.jallcom.2023.172185	-1		The strengthening mechanism of high-entropy alloys (CoCrFeNi/CoCrFeNiMn) is investigated and compared with a single-principle-element alloy (Cu-4Al) with similar stacking fault energy. Hall-Petch effect dominates the strain hardening of both alloys during progressive grain refinement to the ultrafine regime. Moreover, the high density of Lomer-Cottrell locks offers unique and extra hardening to ultrafine-grained high-entropy alloys.
10.1016-j.jallcom.2023.172262	-1		The strange Photo induced micro actuation (PIMA) properties associated with Cu doped Co-Ni-Al Ferromagnetic Shape Memory Alloys (FSMA) has showed enhancement of mechanical properties in our early studies. This enhancement and optimized PIMA properties have opened a scope of various laser-controlled real engineering applications. In this study, we have explored the microstructural scaling and determined the evolved force due to the laser action in optimized Cu doped Co-Ni-Al alloy system with a detailed insight. This unique PIMA property is rare in literature and actual reason are still not explored. EBSD, TEM, AFM/MFM based techniques were further adopted to understand the role of microstructure in more detail. The evolved magnetic domain patterns for actuating and non-actuating alloys have been analyzed in details. Atomic Force Microscopy was adopted to estimate the constitutive mechanical properties of the thin alloy samples by mechanical spectrometry. This estimation was directly used to predict a general trend in force distribution pattern of the Cu-Co-Ni-Al alloys strips through FEM analysis. The crux of FEM based model and its simulated results can be applied for real time PIMA oriented engineering application and device manufacturing. The detail microstructural exploration and its effect in the PIMA response along with generalized deflection-force model have been presented in the current study.
10.1016-j.jallcom.2023.172675	-1		Cu-Fe-P immiscible alloys characterized by heterogeneous lamellar structure were manufactured by laser powder bed fusion (LPBF) and the deformation behavior of LPBF-produced immiscible alloys was investigated systematically. When the linear energy density of 133 J/m is adopted during LPBF, the immiscible alloy exhibits the highest compressive strength (-1 GPa) and engineering strain (-27%). The high strength of the LPBF-produced immiscible alloy is attributed to the heterogeneous lamellar structure including the interconnected Fe2P layer and nano-Fe2P particles as hard phase dispersed in the epsilon-Cu matrix as the soft phase. Moreover, the good ductility is attributed to the fine epsilon-Cu grains as soft phase precipitated within the lamellar Fe2P due to the secondary liquid phase separation (SLPS). This soft-hard-soft heterogeneous microstructure can effectively delay crack growth to exhibit excellent mechanical properties in the LPBF-produced immiscible alloys.
10.1016-j.jallcom.2023.173010	-1		This work presents a method for determining the effective Young's modulus (Eeffective) and Poisson ratio of small specimens of a ternary shape memory alloy (SMA), Cu -Al -Be. The alloys were synthesized uniformly and homogeneously using various concentrations of high purity metals and formed into slabs of different geometrical shapes. The phases and fractional quantities of each sub-alloy composing the SMA were determined using SEM/ EDS data and the lever rule, and confirmed by matching computed and measured X-ray diffraction peak patterns. The Eeffective was determined using the rule of mixtures, employing elastic moduli obtained from Ab initio (Density functional theory) calculations. To address the challenge of determining Eeffective experimentally for small specimens, high frequency ultrasonic waves and vibration spectroscopy were used. The Eeffective was then used in a 3D finite element model to compute the vibrational spectrum's resonance peaks, which were found to match those of the experimental vibrational response. The Eeffective was also compared to the pressure wave (P waves) modulus recovered using non-contact ultrasound waves propagating through the sample's thickness. Discrepancies mainly occurring for alloys with the beta phase were resolved by determining its anisotropic spatial Young's modulus. Overall, the presented method provides a comprehensive characterization of the mechanical properties of small alloy specimens.
10.1016-j.jallcom.2024.173418	15	aging; strength; conductivity; electrical conductivity; electrical; mpa; treatment; strengthening; degrees; cu-; cold; precipitation; tensile strength; tensile; iacs	Cu-Zr-Fe(-Y) alloys were prepared by vacuum melting, and their microstructure, elemental distribution and mechanical properties were analyzed. The microstructure evolution, dislocation morphology and precipitated phase distribution due to aging were investigated by electron backscatter diffraction and transmission electron microscopy. The optimal process parameters for the Cu-Zr-Fe(-Y) alloy after solution treatment at 930 degrees C with 60% cold rolling are 450 degrees C aging for 120 min and 500 degrees C aging for 20 min, resulting in microhardness, electrical conductivity, and tensile strength of 60.9% IACS, 162.4 HV, 512.8 MPa and 54.8% IACS, 177.7 HV, 546.9 MPa, respectively. The addition of Y has a fine grain strengthening effect, resulting in an increase in hardness and strength by 9.4% and 6.6%, respectively. The precipitated Cu5Zr and gamma-Fe phases pinned the dislocations and played a significant role in the aging hardening of the alloy, being the main contributors to the strengthening effects.
10.1016-j.jallcom.2024.173543	-1		W-Cu immiscible bimetallic composite is an electrically and thermally conductive material with high temperature service potential. In present work, to improve its load bearing capacity, Ti and Zr were introduced to enhance the W-Cu interfacial bond strength and to achieve solid solution reinforcement. By infiltration of Cu-Ti/ Zr alloy with different compositions into the W skeleton, both the strength and hardness were enhanced without sacrificing ductility. The Ti/Zr incorporation transformed the incoherent interface of W-Cu to a (W-Ti/Zr)-(CuTi/Zr) semi-coherent interface. By utilizing the EDS technique, significant compositional interdiffusion between immiscible metals was revealed. Moreover, the introduction of Ti/Zr purified grain boundaries by capturing the reactive oxygen to generate TiO2 and ZrO2, which inhibited W-Ti/Zr grain growth by Zenner pinning. As the alloy content rose from 0 wt% to 5 wt%, the average grain size of the W-Ti/Zr (or W) alloy decreased from 2.14 mu m to 1.40 mu m. It is noteworthy that the alloying with 2.50 wt% Ti reached peak microhardness (417 HV), bending strength (1546 MPa), and ultimate tensile strength (532 MPa). However, the presence of Cu-Ti/Zr solid solution and oxide particles increased the scattering effect of electrons in the Cu matrix, leading to a falling in electrical conductivity.
10.1016-j.jallcom.2024.173569	15	aging; strength; conductivity; electrical conductivity; electrical; mpa; treatment; strengthening; degrees; cu-; cold; precipitation; tensile strength; tensile; iacs	Cu-4.44Fe-0.26Cr-0.4Si-0.29Mg (CFCSM) alloy and Cu-4.73Fe-0.3Cr-0.38Si-0.28Mg-0.2Sc-0.24Y (CFCSM-Re) alloy were designed. After a series of thermos-mechanical treatment, the alloy has excellent overall properties. The CFCSM-Re alloy had an electrical conductivity of 65%IACS, a yield strength of 552 MPa, a tensile strength of 634 MPa and an elongation of 8.12%. The mechanical properties and electrical conductivity of the alloy were improved by the joint addition of Sc and Y. In comparison with the CFCSM alloy, the conductivity, yield strength, and tensile strength of CFCSM-Re alloy have increased by 0.8% IACS, 124 MPa and 116 MPa, respectively. In CFCSM-Re alloy, dual-scale (Fe, Cr)3Si phase and micron scale Cu(Y, Sc) phase were successfully constructed. CFCSM-Re alloys were strengthened by precipitates, which contributed approximately 50% of total strength . Adding Sc and Y inhibited the alloy's softening during annealing treatment, resulting in the alloy having high conductivity, high strength, and high elongation. The combined addition of Y and Sc atoms tended to be distributed in positions including vacancy, dislocation, grain boundary and phase interface. Rare earth metals atoms inhibited the movement of dislocations, rotation of grain boundaries and coarsening of precipitates thus endowing CFCSM-Re alloys with excellent strength, elongation and conductivity.
10.1016-j.jallcom.2024.173818	15	aging; strength; conductivity; electrical conductivity; electrical; mpa; treatment; strengthening; degrees; cu-; cold; precipitation; tensile strength; tensile; iacs	The microstructure and properties of the aged Cu-Cr-Zr-Nb alloy were studied by means of hardness tester, universal tensile testing machine, conductivity meter, X-ray diffraction, scanning electron microscope, and transmission electron microscope. The results indicated that the hardness and TS (tensile strength) of the Cu-Cr-Zr-Nb alloy increased first and subsequently decreased with increasing the aging temperature. Nevertheless, the electrical conductivity is gradually increasing. The aged Cu-Cr-Zr-Nb alloy was mostly made up of Cu matrix, Cr particles, Cr2Nb, and CuZr compounds. Due to the effects of dislocations accumulated by cold drawing and twins produced during the aging process, the softening temperature of the alloy reached 590 degree celsius. When the Cu-Cr-Zr-Nb alloy was aged at 490 degree celsius, < 111 > replaced < 110 > in the optimal orientation of the alloy, and the KAM (kernel average misorientation) value inside the alloy was the largest. The alloy exhibited great comprehensive properties at 490 degree celsius for 1 h, with a hardness of 144.4 HBW, a TS of 521 MPa, and an electrical conductivity of 78.3%IACS. The contribution value of YS (yield strength) at different aging temperatures was further calculated. The computational results showed that precipitation strengthening was the main strengthening mechanism of the Cu-Cr-Zr-Nb alloy, and fine-grained strengthening and dislocation strengthening simultaneously played a supplementary role.
10.1016-j.jallcom.2024.173852	-1		Cu alloys with high durability and high thermal and electric conductivities are the key to achieving a more energetically efficient and eco-friendly future. Noble Zr-added oxide-dispersion-strengthened Cu alloys (ODS-Cu) with high strengths are promising materials for meeting all future service requirements. In this study, threedimensional atom probe (3D-AP) and transmission electron microscopy (TEM) revealed that the majority nano-oxide particles in the Zr-added ODS-Cu were novel yttria-stabilized zirconia (YSZ) particles with a diameter of less than 4 nm, which were completely different from Y2Zr2O7 and Y4Zr3O12 observed in other Zr-added ODS alloys. Multiscale observations including small-angle X-ray scattering (SAXS), 3D-AP, and TEM were performed to clarify the morphology of the oxide particles in the Zr-added ODS-Cu. Further strength enhancement through microstructural homogenization and specific incremental strength values were proposed.
10.1016-j.jallcom.2024.173945	14	strength; properties; conductivity; electrical; mechanical; cu-; grain; mpa; electrical conductivity; aging; precipitation; phase; mechanical properties; tensile; phases	The phase transformation process and its impact on the properties of directionally solidified Cu-15Ni-8Sn alloy have been comprehensively investigated. The results show that the phase transformation products during the aging process include the modulation structure, D022 ordered phase, γ′ ordered phase, and ultimately the gamma-D03 phase. The formation of modulation structure and D022/γ′ ordered phases plays a crucial role in improving the mechanical properties of the alloy. During the aging process, the mismatch between the D022/γ′ ordered phases and the matrix increases, resulting in larger coherent strains and further enhancing the mechanical properties. However, the formation of discontinuous precipitates can severely deteriorate the mechanical properties. These precipitates grow by consuming Ni/Sn atoms from both the alpha'-matrix and D022/γ′ ordered phases, thereby disrupting the structure of the D022/γ′ ordered phases. By combining the Johnson-Mehl-Avrami-Kolmogorov and the Arrhenius equation, the kinetics of discontinuous precipitate formation during the aging process of directionally solidified Cu-15Ni-8Sn alloy were analyzed. The activation energy of discontinuous precipitates in directionally solidified Cu-15Ni-8Sn alloy is determined to be 225 kJ/mol. Significantly suppressing the formation of discontinuous precipitation is achieved through improvements in the preparation process.
10.1016-j.jallcom.2024.173996	-1		In order to solve or suppress the problem of macro segregation of Fe phase of Cu-Fe alloy in the traditional casting process, we successfully prepared Cu-10Fe alloy prefabricated slabs with homogeneous and fine microstructure by spray deposition and achieved high strength Cu-10Fe alloy thin strips by subsequent cryorolling. Cryorolling was carried out at different reductions to investigate the relationship between microstructure evolution and mechanical properties. The results show that the spray deposited alloys have good plasticity and low temperature workability. As the reduction increased, the Fe phase becomes more fibrous and the average grain size of the alloy is refined to 0.35 mu m. The {112}<111> texture was gradually transformed into a stabilized {110}<112> texture during cryorolling suggested that the low temperature suppressed cross-slip and improved the strength of the alloy. The mechanical properties of the alloys improved significantly after cryorolling is mainly attributed to the significant grain refinement, dislocation accumulation and the presence of ultrafine grains during the cryorolling process. The successful development of thin strips of Cu-Fe alloy with uniform distribution of Fe phase and high strength provides a new idea for the preparation of thin strips of immiscible alloys such as Cu-Fe alloy.
10.1016-j.jallcom.2024.174091	-1		The nanocrystalline metallic bilayer structure can effectively enhance the strength of Cu alloy while maintaining excellent electrical conductivity. Based on the microstructure evolution of Cu/Ag alloy observed by transmission electron microscope (TEM), molecular dynamics (MD) simulations of Cu/Ag alloy with nanocrystalline metallic bilayer structure were established. The mechanical properties and deformation mechanisms of nanocrystalline Cu/Ag-bilayer alloys were investigated at different temperatures. A mixed Hall-Petch (H-P) relationship was observed between the ultimate stress and the increased layer thickness. In this paper, the deformation mechanism changes from dislocation accumulation at the Cu-Ag interface to dislocation through the Cu-Ag interface. In addition, the data analysis results of elastic modulus showed an approximately linear decrease trend with increasing temperature, and the deformation mechanism shifted from dislocation motion to a combination of dislocation motion and grain boundaries (GBs) diffusion. These findings provide guidance for the design of high magnetic field facility (HMFF) water-cooled magnets and very large-scale integration (VLSI) lead frames.
10.1016-j.jallcom.2024.174260	0	solidification; phase; magnetic; magnetic field; undercooling; field; liquid; separation; peritectic; immiscible; cu-; dendrite; phase separation; microstructure; primary	One-dimensional (1D) and three-dimensional (3D) ultrasounds were introduced into the solidification process of ternary Cu-2.8wt%Ni-0.7wt%Si alloy together with the in -situ measurements of acoustic fields. In the case of 1D ultrasound, stable cavitation was the main form of acoustic energy transmission. The grain size of alpha-Cu dendrites was reduced because stable cavitation improved the wetting between impurities and alloy melt, which further promoted nucleation process. When 3D ultrasounds were applied, transient cavitation was the dominant mode of acoustic energy dissipation. This induced local high undercooling in alloy melt, causing a significant increase in bulk nucleation rates and the formation of numerous tiny alpha-Cu equiaxed grains. Meanwhile, as ultrasonic dimension increased, the strengthened acoustic streaming accelerated solute and thermal diffusion and weakened the preferred orientation of growing alpha-Cu grains. The proportion of low -angle grain boundaries (LAGBs) increased consequently, which suppressed the nucleation and growth of 6- Ni 2 Si discontinuous precipitates (DPs) during subsequent annealing treatment. The tensile strength and electrical conductivity of 3D ultrasonically solidified alloy after annealing reached 688.2 MPa and 2.7 x10 7 S/m respectively, showing obvious advantages in synergetic mechanical and electrical performances.
10.1016-j.jallcom.2024.174558	1	shape; memory; shape memory; damping; martensite; martensitic; damping capacity; transformation; capacity; strain; superelasticity; temperature; cu-al-mn; shape memory effect; effect	In this study, a novel Ni-alloyed Cu-Al-Ga-Fe single crystal alloys were reported for the first time. The microstructure, martensitic transformation, shape memory effect, and superelasticity of Cu-12.5Al-4Ga-3Fe- x Ni ( x = 2, 3, 5) and Cu-13.5Al-4Ga-3Fe- x Ni ( x = 3, 4, 5) were investigated. The results show that Cu-12.5Al-4Ga-3Fe- x Ni ( x = 2, 3, 5) single crystals consist of the parent phase, 18 R martensite, and beta (FeAl) nano -precipitates. As the increase in Al content, Cu-13.5Al-4Ga-3Fe- x Ni ( x = 3, 4, 5) single crystals consist of the parent phase, gamma 1 (Cu 9 Al 4 ) phase, and beta (FeAl) nano -precipitates. The martensitic transition finishing temperatures ( M f ) of 12.5Al alloys are all higher than room temperature, while the reversible martensitic transition finishing temperatures ( A f ) of 13.5Al alloys are all lower than room temperature. Cu-12.5Al-4Ga-3Fe-3Ni single crystal shows the highest SME of 7.6 % with 100% strain recovery. Similarly, the Cu-13.5Al-4Ga-3Fe-3Ni single crystal demonstrated the highest superelasticity of 11 %. Additionally, the Cu-13.5Al-4Ga-3Fe-3Ni single crystal maintained 100 % strain recovery even after 4500 cycles of compression deformation at 6 %, although the critical stress of stress -induced martensite decreased with each cycle. These findings suggest that the Cu-Al-Ga-based shape memory single crystal alloys obtained in this study have promising applications in driving response devices.
10.1016-j.jallcom.2024.174642	2	corrosion; surface; film; electrochemical; films; spectroscopy; layer; current; solution; potential; resistance; composition; x-ray; ions; showed	Copper alloys are prominent materials in ships and marine engineering structures due to their effective antifouling performance. However, the deposition of insoluble corrosion products dramatically deteriorates their antifouling performance during long-term immersion. To solve this conundrum, we have developed a novel Cubased alloy cladding layer containing submicron Cr-rich precipitates, which aims to promote the corrosion products flaking through the effect of precipitates, thus effectively inhibiting microalgae attachment. After being immersed for 180 days, the coverage rates of microalgae on the cladding layer were below 2%, while those on the copper exceeded 40%. The remarkable inhibition of microalgae attachment achieved by the cladding layer is mainly due to the Cr-rich precipitates embedded in the unique and loose multi-layer structure corrosion product as Cr2O3-rich particles, which promotes the corrosion product cracking and flaking. Thereby, the cladding layer kills attached microalgae by increasing their reactive oxygen species (ROS) levels.
10.1016-j.jallcom.2024.174766	-1		Hydrogen compatibility of Cu-Al-Ni-Fe-Mn cast alloys was investigated via slow strain rate tensile tests in highpressure hydrogen gas. Four types of alloys were prepared by varying the Al and/or Ni contents. Larger Al and Ni contents resulted in more elongated microstructures with smaller grains and more precipitates, respectively. The tensile strength of the alloys increased with larger Al and/or Ni contents, whereas the ductility decreased only by adding a larger amount of Al. The maximum tensile strength was produced by adding larger amounts of both Al and Ni, which was fairly higher than those of stable austenitic stainless steels. Despite the difference in the microstructures and tensile strengths of the alloys, the hydrogen contents and hydrogen diffusivities showed no substantial difference. Additionally, their reduction in area measured after the tensile tests was not degraded by the high-pressure hydrogen gas, revealing an excellent resistance to hydrogen embrittlement.
10.1016-j.jallcom.2024.174849	-1		In this work, Cu-1.5 wt%Y (Cu-Y) and Cu-0.75 wt%Y-0.75 wt%La (Cu-Y-La) were prepared by mechanical alloying combined with spark plasm sintering and hot rolling, followed with annealing at different temperatures. The effects of the introduction of La and annealing temperatures on the microstructures, mechanical properties, electrical conductivity and thermal stability of Cu-Y alloys were investigated. Both Cu-Y and Cu-Y-La obtain the heterogeneous mixed grain structures composed of coarse grains and fine grains, and oxide nanoparticles are uniformly dispersed in Cu matrix. With the introduction of La, the grains and oxide nanoparticles are refined, and LaYO3 nanoparticles with the coherent interfacial structure can be observed in Cu-Y-La. After annealing at 500 degree celsius, both Cu-Y and Cu-Y-La obtain the most excellent comprehensive tensile properties and highest electrical conductivity (63 %IACS for Cu-Y and 62 %IACS for Cu-Y-La). Benefited from effectively enhanced grain boundary strengthening and particle strengthening mechanisms induced by the combination effect of La and Y, Cu-Y-La shows higher strength than that of Cu-Y (after annealing at 500 degree celsius, 244 MPa of yield strength for Cu-Y and 300 MPa for Cu-Y-La). Meanwhile, benefited from improved dynamics stability of the Cu matrix induced by significantly refined precipitates and the formation of LaYO3 nanoparticles with the coherent interfacial structure after introducing La, the better softening resistance is achieved by Cu-Y-La in comparsion with Cu-Y, and almost 100 degree celsius improvement of the softening temperature is achieved (966 degree celsius for Cu-Y-La and 870 degree celsius for Cu-Y).
10.1016-j.jallcom.2024.174928	-1		Based on laser -induced deep etching technology and through -hole filling techniques, TGV interposers were successfully fabricated. The residual stress in the Cu overburden film directly affects the yield improvement after subsequent grinding of the interposer. Therefore, we studied the evolution of residual stress, microstructural changes, and micro -nano mechanical properties within the Cu overburden film after heat treatment at different temperatures. Residual stress analysis using the sin 2 Psi method with an X-ray diffractometer (XRD) indicates that during the process of increasing temperature from 100 degrees C to 200 degrees C, the internal residual stress in the Cu overburden film changes from compressive stress to tensile stress. Furthermore, the maximum absolute value of the residual stress, 70.09 MPa, appears at room temperature, and the minimum absolute value of the residual stress, 15.59 MPa, occurs after the heat treatment process at 200 degrees C. Electron backscatter diffraction (EBSD) microstructural analysis shows that the application of heat treatment can effectively accelerate static recrystallization (SRX), promote a higher proportion of high -angle grain boundaries (HAGB), and refine grain size. Additionally, a (001) preferred orientation at high residual stress states and a (111) preferred orientation at low residual stress states are observed. Nanoindentation test results indicate that the Cu overburden film treated at 100 degrees C has the most potential for removal during the grinding process.
10.1016-j.jallcom.2024.175077	-1		Synergistic effects of a novel Cu 51 Hf 14 inoculant and Zr element on the microstructure, mechanical and damping properties of Cu-Al-Mn shape memory alloy were investigated. The results showed that grains of the alloy could be significantly refined due to the heterogeneous nucleation of Cu 51 Hf 14 and the pinning effect of AlCu 2 Zr particles on grain boundaries (GBs), the martensite lath was also greatly refined. Mechanical properties were improved obviously, the alloy with the smallest grain size showed the highest tensile strength and elongation. This attributed to grain refinement, increasing difficulty of grain coordination deformation, decreasing mobility of martensite variants and the pinning effect of AlCu 2 Zr on dislocation. The compound refining alloys possessed high room -temperature damping owing to the increased interface density and the uncoordinated deformation of AlCu 2 Zr and Cu-Al-Mn matrix. While its high -temperature damping was lower than that of the inoculated alloy because of the decreasing martensite content caused by the increasing GB influence zone and the precipitation of AlCu 2 Zr.
10.1016-j.jallcom.2024.175574	14	strength; properties; conductivity; electrical; mechanical; cu-; grain; mpa; electrical conductivity; aging; precipitation; phase; mechanical properties; tensile; phases	Cu-Hf alloys, which exhibit electrical conductivity up to 80 %IACS, are promising high-strength and highconductivity copper alloys. However, the performance of Cu-Hf alloys under different thermos-mechanical processes (TMP) remains unclear. This work systematically investigates the microstructural evolution and property changes in Cu-0.9Hf alloy subjected to four prevalent TMP routes, including solid solution-aging, solid solution-cold rolling-aging, multi-step TMP, and TMP combined with pre-aging. The pre-aged Cu-0.9Hf alloy demonstrates the highest strength (666 MPa), while the multi-stage TMP Cu-0.9Hf alloy achieves optimal comprehensive properties: 628 MPa and 77.7 %IACS. The Corresponding strengthening-mechanism analysis indicates that dislocation-strengthening is the primary contributor. Additionally, the Cu-0.9Hf alloy exhibits good high-temperature softening resistance in this work. Microstructural analysis reveals that despite precipitate coarsening and morphological evolution during aging, the Cu matrix maintains a high dislocation density without apparent recrystallization, even at the over-aging stage. The pinning effects of Hf-containing second phases on dislocations during aging are crucial for the alloy's excellent softening resistance.
10.1016-j.jallcom.2024.175600	-1		In general, when the oxide content is controlled within 5 wt%, increasing the content of oxides is crucial for improving the strength, hardness, and wear resistance of oxide dispersion strengthened copper alloy (ODS-Cu). However, the oxide content of commercially available ODS-Cu fabricated with internal oxidation (e.g. Glidcop60) is limited to 1.1 wt% due to the adverse effects of irregular growth of oxide particles on overall properties when the oxide content increases. In this study, we introduced oxide particles into Cu matrix via internal oxidation of Cu-Al and Cu-Al-Ti alloys using Rhines-pack method. The origin of irregular oxide particles, oxide bands and healing layers formed in the oxidized layer of the ODS-Cu alloys with high oxide content was revealed. Furthermore, it is found that the doping of Ti can effectively suppress the growth of irregular oxide particles and the formation of oxide bands. In the specimens with a Ti/Al molar ratio of 0.28, Ti has a better inhibitory effect on oxide particle coarsening, and this inhibitory effect is more pronounced when ODS-Cu containing higher oxide content. Compared to Cu-0.6 %Al alloy, the average occurrence and length fraction of oxide bands in Cu0.6 %Al-0.3 %Ti alloy are significantly reduced (by 81 % and 95 % respectively), and the fraction of oxide particles smaller than 20 nm is significantly increased (from 5 % to 76 %). This Ti-doping strategy solves the dilemma in increasing the oxide content in ODS-Cu produced by internal oxidation, and also provides the possibility for industrial production of high oxide volumetric fraction ODS-Cu with internal oxidation.
10.1016-j.jallcom.2024.175604	-1		In order to reveal and predict the strain hardening behaviors of metallic materials, mechanical properties of CuAl alloys processed by rolling were investigated by tensile tests. The microstructure evolution of Cu-Al alloys processed by rolling were characterized. The true stress-strain curves were fitted by an exponential strainhardening (ESH) model. Based on the microscopic mechanism of dislocation growth and annihilation, the true stress strain curves were predicted through macroscopic mechanical properties. The strengthening effects on CuAl alloys of different methods were analyzed quantitively by hardening exponent z and saturation strength 6s which were derived from the ESH model. The fundamental assumptions and physical meaning of parameters have been validated by investigating strain hardening behaviors of Cu-Al alloys. The limited applicable materials and future research of ESH model are also proposed for the further development. This study could provide guidance to understand work-hardening behavior and predict tensile performance of Cu-Al alloys.
10.1016-j.jallcom.2024.175672	14	strength; properties; conductivity; electrical; mechanical; cu-; grain; mpa; electrical conductivity; aging; precipitation; phase; mechanical properties; tensile; phases	Copper is a widely used material but is susceptible to oxidation under atmospheric conditions, resulting in the formation of oxide layers that are prone to cracking and peeling even under minimal mechanical stress. To address this issue, the development of a dense and solid copper oxide layer with strong oxide-copper interfacial bonding is crucial; however, achieving such strong bonding is challenging owing to the substantial lattice misfit of approximately 18 %. This study presents a novel approach to create an adhesive and robust Cu2O layer on copper through a simple and reproducible heat treatment procedure conducted under extremely low air pressures in vacuum conditions. Remarkably, an unexpected reduction in lattice misfit at the interface is achieved by promoting the growth of a large-grain oxide layer that fully covers the copper surface. Despite the presence of arbitrary crystallographic relationships between copper and Cu2O, the crystallographic orientation of copper is intentionally altered by introducing geometrically necessary dislocations and atomic array tilting, which results in the formation of a stable oxide layer that exhibits exceptional resistance against cracking, peeling, plastic deformation, and mechanical scratching. The effectiveness of this approach is demonstrated by the enhanced robustness and stability it imparts to copper oxides.
10.1016-j.jallcom.2024.175897	14	strength; properties; conductivity; electrical; mechanical; cu-; grain; mpa; electrical conductivity; aging; precipitation; phase; mechanical properties; tensile; phases	In this study, Cu-Ti-Zr and Cu-Ti-Zr-Mg alloys were subjected to solid annealing and aging under different conditions following 80 % cold rolling, in order to investigate the impact of Mg addition on the microstructure and properties of Cu-Ti-Zr alloys. The results reveal that the ultimate tensile strength and total elongation of the Cu-Ti-Zr alloy under peak aging condition are 771 MPa and 4.7 %, respectively, while for the Cu-Ti-Zr-Mg alloy, these values are 823 MPa and 4.4 %. EBSD (Electron Back Scatter Diffraction) analysis indicates that the addition of Mg promotes recrystallization in the Cu-Ti-Zr alloy. The texture strength of the Cu-Ti-Zr-Mg alloy is lower compared to the Cu-Ti-Zr alloy at peak aging, with the predominant texture being Copper texture. TEM (Transmission Electron Microscope) observations showed changes in the types and matrix relationships of precipitates due to Mg addition. The primary strengthening mechanism of both alloys is precipitation strengthening. Precipitation kinetic equations for the two alloys were established, revealing that Mg addition reduces the incubation period of the Cu-Ti-Zr alloy during aging.
10.1016-j.jallcom.2024.175905	-1		Cu-12.5Ni-5Sn-xY alloy with different rare earth Y contents was prepared by spark plasma sintering (SPS). The samples underwent aging at approximately 400 degrees C degrees C for 4 hours in an energy-saving box furnace. The effect of trace Y addition on the microstructure and corrosion behavior of aging treated Cu-12.5Ni-5Sn-xY alloy were investigated by electrochemical test, and the corrosion mechanism of the alloy was discussed. The results indicated that the addition of rare earth Y improved the uniformity of microstructure and grain size of the alloy, and improved the corrosion resistance of the alloy. When the Y content changed between 0 wt% and 1.0 wt%, the corrosion resistance of the Cu-12.5Ni-5Sn-xY alloy gradually improved. The Cu-12.5Ni-5Sn-1.0Y alloy had a lower self-corrosion current density (1.490x10-- 5 A/cm 2 ) and a lower corrosion rate (0.178 mm/a). Compared to the Cu-12.5Ni-5Sn alloy without Y addition, the maximum corrosion depth was reduced by about 44.6% and the corrosion resistance was improved. Rare earth Y promoted the uniform distribution of Ni elements, inhibited the conversion of Cu2O 2 O to Cu2(OH)3Cl, 2 (OH) 3 Cl, enhanced the layer density and stability. The internal corrosion layer mainly consisted of NiO, the intermediate layer mainly consisted of SnO, and the surface layer mainly comprised of CuO, Cu2O, 2 O, and Cu2(OH)3Cl. 2 (OH) 3 Cl. Additionally, Y2O3 2 O 3 formed on the alloy's surface, effectively prevented corrosive ion attack and enhanced the corrosion resistance of Cu-12.5Ni-5Sn alloy.
10.1016-j.jallcom.2024.175925	-1		This study investigated the effects of aging treatments (200-500 degrees C, 1 h) on the Cu-11.1Al-8.15Mn-0.37Si shape memory alloy manufactured using laser powder bed fusion (LPBF). As the aging temperature increased, the residual stress of the alloy decreased, and the microstructure transitioned from an austenite-martensite dualphase structure to an austenite single-phase structure. A phenomenon of martensite stabilization induced by lowtemperature aging at 200-300 degrees C was observed, leading to increased phase transformation temperatures and decreased mechanical properties. After aging at 400 degrees C, the plasticity was improved and the shape memory effect (SME) recovery strain experienced a significant 48 % enhancement and reached a maximum value of 3.10 %. This enhancement was due to the improved ordering and texture homogenization of the austenite phase, confirmed by EBSD results. Meanwhile, EPMA analyses revealed the pinning effect of Mn5Si3 precipitations migrated from the grain interior to the grain boundaries which no longer obstructed the movement of martensitic habit planes during the recovery process. Thus, the SME improved. Additionally, after aging at 500 degrees C, a large amount of alpha phase precipitated along grain boundaries leading to a decrease in mechanical properties. These findings underscore the importance of tailored aging treatments for optimizing shape memory properties in LPBF-manufactured Cu-based shape memory alloys.
10.1016-j.jallcom.2024.175974	-1		Recrystallization annealing is a necessary process for refining the grain of processed metallic materials and eliminating work hardening. However, it can cause a large amount of precipitation and coarsening of the second phase in supersaturated solid solution alloys, which is detrimental to the subsequent processing and aging processes aimed at controlling the precipitation phase. This article compared the effects of electropulsing (EPT) and conventional heat treatment (CHT) processes on the microstructure and mechanical properties of cold-rolled Cu-3.5Ti alloy. The results indicated that compared with CHT, EPT achieved full recrystallization of the alloy at a lower temperature (650 degrees C, 100 degrees C lower than CHT) and in a shorter time (10 s, 1/360 of CHT), and effectively inhibited the precipitation of beta- Cu 4 Ti phase, resulting in a fine and uniform supersaturated solid solution. This process significantly improved both the strength and plasticity of the alloy. The yield strength, tensile strength and elongation to failure of the EPT-650 degrees C/10 s sample were 570 MPa, 598 MPa and 21.2 %, respectively, which were 27.8%, 25.9% and 19.1 % higher than those of the CHT-750 degrees C/1 h sample. EPT significantly increased the recrystallization nucleation rate of the alloy, while its rapid heating method inhibited the precipitation of beta- Cu 4 Ti phase, ensuring the recrystallization process was not affected by the precipitated phase, which was the main reason for rapid recrystallization and grain refinement of Cu-3.5Ti alloy by EPT at lower temperatures and shorter time.
10.1016-j.jallcom.2024.176077	-1		Composite materials are widely used in technology. The choice of exact composite material depends on its purpose, functional properties, stability of parameters over time, and specific conditions of use. In this work, the wettability of various materials was studied. The materials used were processed in two ways: polishing and laser texturing with and without craters. The surface wettability using molecular dynamics methods was modeled when changing the concentration of the reinforcing component in the composite. The crystalline grain orientation and surface roughness of the Cu-SiC composite after texturing is different from Cu, which is important to consider when modeling the wettability. The sensitivity of the wettability of various materials to the surface temperature (Delta theta 0/Delta Tw) was studied experimentally. The maximum sensitivity of the contact angle to temperature was found for the superhydrophobic surface. The minimum sensitivity was observed for polished AlMg3 surface. Power-law dependences of the evaporation rate of water droplet on the contact angle were obtained for various materials in the temperature range of 25-90 degrees & Scy;. As the droplet diameter increases, the influence of the wetting diameter on the evaporation rate decreases, while that of convection increases. The data obtained can be useful for the development of composite materials technologies and optimization of their functional properties.
10.1016-j.jallcom.2024.176143	-1		Cu-Ti3SiC2 composites were prepared by solid-liquid mixing, mechanical alloying and discharge plasma sintering. The composites' internal structure and performance characteristics were characterized using OM, SEM, XRD, TEM, conductivity and mechanical tests. The interaction of Ti3SiC2 with the Cu matrix was systematically investigated. The formation of Cu5Si, Cu15Si4 and TiC particles was found to optimize the bonding of Ti3SiC2 with the copper matrix. Also, the effect of different Ti3SiC2 contents (0.5, 1, 2 and 3 wt%) on the materials' internal structure and performance parameters was investigated. The results showed that the samples of Cu-1 wt% Ti3SiC2 exhibit excellent overall performance. It achieved a yield strength of 270.4 MPa, a tensile strength of 295.2 MPa, an elongation rate of 23.8 %, an electrical conductivity of 85.8 % (IACS), a coefficient of friction of 0.465, and a wear rate of 7.8x10(-5) mm(3)N(-1)m(-1).
10.1016-j.jallcom.2024.176186	14	strength; properties; conductivity; electrical; mechanical; cu-; grain; mpa; electrical conductivity; aging; precipitation; phase; mechanical properties; tensile; phases	Building upon the high-performance Cu-13.3Ni-6.7Al alloy, we investigated the effects of microalloying with four different Mg concentrations: 0.25 at%, 0.50 at%, 1.00 at%, and 2.00 at% on the microstructure and properties of ultra-high strength, conductive Cu-Ni-Al alloys. Notably, the alloy containing 1.00 at% Mg, after aging treatment at 500 degrees C for 24 hours, exhibited superior comprehensive properties. The ultimate tensile strength and electrical conductivity reached 1092 MPa and 16.4 %IACS, respectively, representing an 8.3 % increase in tensile strength and a 2.5 % increase in electrical conductivity compared to the Cu-13.3Ni-6.7Al alloy. At this optimal concentration, the grain size of the alloy was reduced from 1.5 mu m to 1.3 mu m, the precipitate size decreased from 9.9 nm to 9.0 nm, and the volume fraction of precipitates increased from 8.0 % to 8.8 %. These changes resulted in grain boundary strengthening, dislocation strengthening, and precipitation strengthening effects of 125 MPa, 155 MPa, and 690 MPa, respectively. The addition of Mg effectively lowered the interfacial energy of Ni3Al 3 Al precipitates, thereby enhancing the nucleation rate of the precipitates and subsequently improving the alloy's overall mechanical and electrical properties. This study provides valuable insights into the appropriate alloying elements for designing high-performance Cu-Ni-Al alloys.
10.1016-j.jallcom.2024.176243	7	irradiation; shear; grain; ta; deformation; size; radiation; voids; nanocrystalline; simulations; similar; void; temperature; irradiated; boundaries	The crystallization route and kinetics of a Cu-Zr-Al bulk metallic glass (BMG), based on Cu50Zr50, were investigated using in-situ synchrotron small- and wide-angle X-ray scattering (SAXS/WAXS), in-situ high-energy X-ray diffraction (HEXRD), and differential scanning calorimetry (DSC). The acquisition of kinetic diagrams of SAXS/ WAXS enables the direct construction of the overall phase transformation route from room temperature to the onset temperature of solid state phase transformation upon heating. It is revealed that the studied alloy undergoes multiple steps (at least five steps) before reaching the high-temperature thermodynamic equilibrium. This is distinct from the commonly believed simple path of glass -> Cu10Zr7 + CuZr2 -> B2-CuZr predicted by the Cu-Zr equilibrium phase diagram. In addition to thermodynamics, we emphasize that kinetic factors play a prominent role in the phase transformation process of Cu-Zr-Al BMGs. Furthermore, isothermal crystallization kinetics analyses conducted by in-situ HEXRD and DSC indicate that the formation of the initial crystalline phase, specifically the Cu10Zr7, follows an interface-controlled quasi-polymorphic process with an increasing nucleation rate. The findings of this study may provide novel insights into the crystallization mechanism of glass-forming supercooled liquids from a thermophysical perspective.
10.1016-j.jallcom.2024.176467	14	strength; properties; conductivity; electrical; mechanical; cu-; grain; mpa; electrical conductivity; aging; precipitation; phase; mechanical properties; tensile; phases	The solid-state forming capabilities of cold spray additive manufacturing (CSAM) offer a new method for creating nano-reinforced materials. However, the interface of the deposits often fails to form strong metallurgical bonds, leading to mechanical defects that weaken the material. This study investigates the preparation of highly plastic nano-alumina dispersion-strengthened copper by combining CSAM with friction stir processing (FSP), both solidstate techniques. The results show that FSP treatment fuses the interfaces of the deposited particles, transforming the microstructure from multi-scale, elongated grains to a uniform ultrafine-grained (UFG) structure. The average grain size reduces from 3.1 mu m to 0.86 mu m, and the proportion of high-angle grain boundaries increases from 42.5 % to 85.2 %. This treatment significantly enhances both mechanical and electrical properties. The ultimate tensile strength increases from 210 MPa to 450 MPa, elongation at break improves from 1 % to 35 %, and electrical conductivity rises from 70 % IACS to 81 % IACS. These findings demonstrate the potential of the combined CSAM-FSP approach for producing high-performance nano-alumina dispersion-strengthened copper with superior mechanical and electrical properties.
10.1016-j.jallcom.2024.176509	-1		The leadframe is a crucial part that is frequently employed in electronic equipment, and the stability and dependability of the device are directly impacted by its performance. In this work, the microstructural evolution of Cu-2.13Fe-0.026P alloy and the relationship between the texture intensity and residual stress under different annealing time are investigated by scanning electron microscopy (SEM), backscattering diffractometer (EBSD), and nanoindentation instrument, and the corrosion behavior of the alloy in HCl and CuCl2 solution systems was summarized. It was found that regulating the texture intensity of the alloys could significantly influence the residual stresses. The residual stress is not monotonically decreasing with time, and the alloys have the lowest residual stress when annealed for 10 min. In addition, the experiments pointed out that the microstructure is essential for the etching performance of copper alloys. The role of low-Sigma coincidence site lattice (Sigma CSL) grain boundaries in the connectivity of the random high-angle grain boundaries (RHAGB) network leads to better etching performance of the 10-minute annealed alloys than the 30-minute alloys, providing new perspectives on optimizing the microstructure of thin strips of etched copper alloys.
10.1016-j.jallcom.2024.176883	-1		Carbon fibers (CFs) and carbon nanotubes (CNTs) reinforced Cu composites doped by Zr70Cu30 70 Cu 30 alloy particles were fabricated by a conventional vacuum hot-press technique and their microstructures, mechanical properties and electrical conductivities were compared. The results revealed that the CNTs/Cu composite exhibited a superior combination between mechanical properties and electrical conductivity, having the highest relative density of 94.8 %, the maximum microhardness of 85.7 HV and the maximum electrical conductivity of 84.2 % IACS among various composites. The incorporation of Zr70Cu30 70 Cu 30 alloy particles led to limited contacts with CFs (or CNTs) reinforcements but caused the decrease of relative density and consequently the deleterious mechanical and electrical properties. The dominant strengthening mechanism for the fabricated Cu matrix composites was load transfer mechanism. The CNTs reinforcements demonstrated the highest reinforcement efficiency in the Cu matrix composites, which can provide some new insights for designing novel high-strength and high-connectivity Cu matrix composites.
10.1016-j.jallcom.2024.177198	14	strength; properties; conductivity; electrical; mechanical; cu-; grain; mpa; electrical conductivity; aging; precipitation; phase; mechanical properties; tensile; phases	In this study, porous Cu-Al-Si intermetallic compounds with three-dimensional structures were rapidly prepared by a novel self-exothermic reaction. By this method, Si was successfully solid-solved into CuAl intermetallic compounds and achieved better fusion with them. The effects of Si addition on their oxidation resistance and corrosion resistance were compared. The findings indicate that the minimum weight gain of the Cu-Al-Si product is only 1.48 % after oxidation at 800 degrees C for 288 h . Si facilitates the creation of a continuous Al2O3 protective layer on the surface of the porous Cu-Al-Si intermetallics skeleton, thereby preserving its internal structure while significantly enhancing its oxidation resistance. The incorporation of Si to Cu-Al intermetallics enhances the stability of the passivation film on the material's surface, increases the resistance of the passivation film, and effectively restricts the electrochemical reaction between the material and the corrosive medium.
10.1016-j.jallcom.2024.177315	-1		Cu-W composites with good mechanical properties, electrical properties and corrosion resistance are still rare. In this study, Y2O3 reinforced Cu-10W composites were prepared by spark plasma sintering. The effects of different Y2O3 contents on the corrosion resistance of Cu-10W composites were studied by static immersion corrosion and electrochemical corrosion. The results show that, the incorporation of Y2O3 makes the microstructure of Cu-10W composites dense and grain refinement. The minimum weight loss value can be obtained when Y2O3 content is 2 wt%. Y2O3 can effectively increase the self-corrosion potential and corrosion current density of Cu-10W composites and enhance the electrochemical impedance level. And Y2O3 can increase the resistivity ring radius, which leads to the increase of charge transfer resistance Rct and the decrease of Warburg impedance Zw.
10.1016-j.jallcom.2024.177455	-1		In order to improve the performance of metal-bonded grinding wheels, the cBN/Cu-Zn-Ti composites were fabricated by pulse current sintering with several different Co contents (i.e., 5, 10, and 15 wt%) were added. The specimen microstructure, interfacial analysis and fracture morphology of pulse current sintering cBN grain were characterized by scanning electron microscopy (SEM), energy dispersive spectroscopy (EDS), and X-ray diffraction (XRD). The mechanical properties of hardness, wear resistance, and three-point bending strength of the fabricated specimens were tested. The electrochemical properties was also tested. The specimen shape fabricated by pulse current sintering using the composite Cu-Zn-Ti alloy doped by Co was better than pure Cu-ZnTi alloy. The microscopic analysis revealed that TiB2 and TiN were maintained between the Cu-Zn-Ti composites and cBN. With the addition of Co, the hardness, flexural strength and wear resistance of the specimens are improved. The new phase CoTi3 enhancing strength of the metal composite via the Orowan mechanism. The S5 specimen containing 15 wt% Co particles has the highest flexural strength, which is 485.83 MPa and satisfies the requirements of high speed grinding. Meanwhile, when the Co content reaches 10 %, the lowest friction coefficient (0.217) and lowest wear rate (0.81 mg) are achieved for the sample. With the addition of Co, the corrosion resistance of the material is significantly improved.
10.1016-j.jallcom.2024.177476	14	strength; properties; conductivity; electrical; mechanical; cu-; grain; mpa; electrical conductivity; aging; precipitation; phase; mechanical properties; tensile; phases	This study introduces a novel approach to enhance the strain recovery characteristics of Cu-Al-Ni high-temperature shape memory alloys by introducing Sr elements to optimize the proportion of martensitic variants. First-principles calculations show that adding Sr can effectively reduce the stacking fault energy, which facilitates the transformation from the 2 H to the 18 R phase. Subsequently, the proportion of the 18 R phase significantly increases to 83.7 % in the Cu-Al-Ni-Sr alloys. Meanwhile, we identified a unique alternating structure with the co-existence of two different martensite phases, strongly supporting that Sr addition promotes extensive 2H-to-18R phase transformation and enhances the shape memory effect. Compression tests revealed that the Sr doping improved the shape memory effect recovery strain from 2.6 % to 5.0 % with 8 % pre-strain, while reducing irreversible strain. These findings demonstrate that tailoring martensite variant ratios through specific alloying can significantly enhance the strain recovery properties of Cu-Al-Ni alloys, offering a new strategy for developing high-performance shape memory alloys.
10.1016-j.jallcom.2024.177705	14	strength; properties; conductivity; electrical; mechanical; cu-; grain; mpa; electrical conductivity; aging; precipitation; phase; mechanical properties; tensile; phases	In this study, Cu-Mn-P alloys with Mn/P atomic ratios ranging from 1 to 3 were designed based on computational phase diagrams. The microstructures of these alloys were systematically investigated using a combination of TEM, EPMA, EBSD, and XRD. The results indicate that the alloy with a Mn/P atomic ratio of 2 exhibits optimal comprehensive properties. A simple thermomechanical treatment involving solution treatment followed by 70 % cold rolling and aging at 400 degrees C for 6 hours resulted in a hardness of 186.8 HV, a tensile strength of 577 MPa, a yield strength of 548 MPa, and an electrical conductivity of 63.5 % IACS. Alloys with Mn/P ratios below 2 showed a reduced density of precipitates, leading to diminished precipitation hardening, while higher ratios resulted in increased manganese content in the solid solution, causing lattice distortions and reduced conductivity. TEM analysis confirmed that the precipitated phase was rod-shaped hexagonal Mn2P, which grew along the (100) plane of the matrix and maintained a coherent interface with the matrix. This research provides insights for the future development of high-performance quaternary Cu-Mn-X-P alloys.
10.1016-j.jallcom.2024.177810	14	strength; properties; conductivity; electrical; mechanical; cu-; grain; mpa; electrical conductivity; aging; precipitation; phase; mechanical properties; tensile; phases	The effects of two-stage cold rolling and aging treatment on the mechanical and electrical properties of Cu-Ni-Ti alloy were investigated. The microstructure evolution, precipitation behavior, and strengthening mechanism of the alloy after two-stage cold rolling and aging treatment were analyzed using microhardness, tensile strength, and electrical performance tests, combined with transmission electron microscopy (TEM) and electron backscatter diffraction (EBSD) techniques. The research results show that the alloy after two-stage cold rolling and aging treatment exhibits excellent comprehensive properties, tensile strength reaches 635 MPa, yield strength is 597 MPa, hardness is 182 HV, conductivity is 62.1 % IACS, and elongation is 14.5 %. This processing method facilitates the precipitation of more nanoscale Ni3Ti phases and the formation of smaller cellular substructures. Consequently, the alloy maintains its exceptional mechanical properties through the combined effects of dislocation and precipitation strengthening. This study provides a novel preparation process and a solid theoretical foundation for enhancing the mechanical and electrical properties of Cu-Ni-Ti alloys.
10.1016-j.jallcom.2024.177869	14	strength; properties; conductivity; electrical; mechanical; cu-; grain; mpa; electrical conductivity; aging; precipitation; phase; mechanical properties; tensile; phases	Reducing or completely eliminating the reticular grain boundary phases in alloys is crucial for enhancing the mechanical and electrical properties of Cu-Ni-Si alloys with high nickel and silicon content (Ni + Si > 5 wt%). In this study, we investigated the microstructure, mechanical properties, and electrical conductivity of Cu-8Ni-1.8Si (wt%) alloy prepared by high-pressure solidification (HPS) and subsequent aging treatment. The interfacial growth stabilizes as the pressure reduces the crystal growth rate, inhibits the diffusion of solute atoms, and increases the solute partition coefficient. The reticulated Ni31Si12 and granular Ni2Si phases disappear under 6 GPa pressure, forming a complete Cu (Ni, Si) solid solution. After direct aging treatment, the precipitated phase of the HPS alloy is beta-Ni3Si at the early stage of aging. At the peak aging state, beta-Ni3Si and delta-Ni2Si phases coexist in the matrix. Additionally, the Avrami equations for the phase transition kinetics of HPS alloys at different aging temperatures were derived from the electrical conductivity data, and the strength contributions from solid solution strengthening and precipitation strengthening were calculated. The alloy aged at 450 degrees C exhibited the largest volume fraction and the smallest average size of precipitates, resulting in a more pronounced obstruction effect of nano precipitates on dislocation bypassing and demonstrating the best precipitation strengthening effect. At the peak aging states, the alloy's hardness reaches 367.5 HV, and the compressive yield strength reaches 788.2 MPa. These results indicate that high pressure is an effective method to improve the solid solution degree of alloying elements and enhance the mechanical properties of Cu-Ni-Si alloys.
10.1016-j.jallcom.2024.177874	14	strength; properties; conductivity; electrical; mechanical; cu-; grain; mpa; electrical conductivity; aging; precipitation; phase; mechanical properties; tensile; phases	This study proposes a novel strategy based on a CALPHAD/MD coupling model to reveal the influence of microstructure evolution on the mechanical properties of Cu-Pb-(Sn) alloys. The CALPHAD method is utilized to calculate the phase composition and fraction of Cu-Pb-(Sn) alloys, followed by the establishment of MD geometric models to simulate the actual microstructure evolution. The results demonstrate that the addition of Sn promotes the transformation of secondary phases (SPs) from a continuously reticular to a dispersedly granular morphology, significantly enhancing the strength and ductility of the alloys. By conducting MD tensile simulations on SPs with different morphologies, this study further elucidates the mechanism by which the evolution of SP morphology impacts the mechanical properties of the alloys. The final MD simulation results are in excellent agreement with experimental data, validating the effectiveness of the proposed model. This work provides new insights into the relationship between microstructure and mechanical properties in Cu-Pb-(Sn) alloys and offers a reference for the study of other alloy systems.
10.1016-j.jallcom.2024.177947	-1		The Ti element was designed to optimize the Cu/Nb interface structure. The Cu-Nb and Cu-Nb-Ti alloys were successfully prepared by laser directed energy deposition. Results show that the introduction of Ti can change the incoherent Cu/Nb interface into the semi-coherent Cu/(3-Cu3Ti/Nb interface. The Cu/Nb interfaces are easily sheared, producing an attractive force on the dislocations, and the dislocations pile up at the incoherent Cu/Nb interfaces. As a consequence, the Cu-Nb deposited alloy exhibits a relatively low total elongation of 7.7 +/- 1.1 %. Instead, semi-coherent Cu/(3-Cu3Ti/Nb interfaces change the movement of dislocations, making it easier for dislocations to transmit across the interface, thus relieving the stress concentration at the interface, which endows the Cu-Nb-Ti deposited alloy the higher total elongation of 13.4 +/- 0.2%. In addition, due to the precipitation strengthening and solid solution strengthening, the Cu-Nb-Ti deposited alloy exhibits higher strength of 795 +/- 7 MPa.
10.1016-j.jallcom.2024.178111	-1		In this study, the Cu-15Ni-8Sn (wt%) based alloys were fabricated using the hot isostatic pressing (HIP) process and treated with hot forging and heat treatments to improve performance. The effects of hot forging and heat treatments on the microstructure and mechanical properties were investigated. The results show that the microstructure of the as-HIPed sample is mainly composed of alpha-Cu matrix, gamma phase, Nb-rich phase and O-rich phase. After homogenization, the gamma phase is almost dissolved into the matrix and Ni3Nb particles form. Hot forging significantly reduces the O-rich phases, and during aging treatment, nano-ordered phases precipitate uniformly throughout the matrix. Tensile test results demonstrate an improved combination of strength and plasticity of the Cu-15Ni-8Sn-0.18 Nb alloy after hot forging and heat treatments, with the hot-forged and then heat-treated sample achieving an ultimate tensile strength (UTS) of 1181.7 MPa, yield strength (YS) of 779.8 MPa, and elongation (EL) of 18.2 %. Compared to the as-HIPed sample, the UTS is increase by 349.8 MPa and the EL is increased by 6.8 %. This notable increase in UTS is mainly attributed to the precipitation strengthening of nano-ordered precipitates. The improvement of EL could be attributed to dissolution of gamma phase and reduction of O-rich phases. This provides valuable insights into the control of microstructures and mechanical properties of Cu-Ni-Sn based alloys.
10.1016-j.jallcom.2024.178152	-1		Structural regulation of both macro-shape (cubes, films) and microstructure (ligament size, porosity) of nanoporous metals is of central importance for their fundamental studies and practical applications. The choice of dilute solid solutions as precursors for dealloying provides great chances for structural regulation of nanoporous metals, but has received little attention. Herein, a series of dilute Cu-Au solid solution foils with 0.001-5 at% Au were dealloyed in HNO3 solutions, and monolithic nanoporous gold (NPG) films with different microstructures/compositions were fabricated. After dealloying, all the NPG films manifest a considerable degree of volume shrinkage (61.9-99.9 %), high porosity (up to 91.0 %), and low density (0.9-3.8 g cm(-3)). Furthermore, the NPG samples maintain their initial foil shape even when the atomic ratio of Au in the Cu-Au precursor is as low as 0.01 at% (that is, Cu99.99Au0.01). All the NPG samples feature an open, three-dimensional, bi-continuous ligament-channel structure at the nanoscale. The ligament size of the NPG samples shows a negative correlation with the residual amount of Cu after dealloying. We further investigated the phase transformation behavior of Cu99.9Au0.1 and surface morphology evolution of Cu99.99Au0.01 using in-situ X-ray diffraction (XRD) and ex-situ scanning electron microscopy (SEM) techniques.
10.1016-j.jallcom.2024.178386	14	strength; properties; conductivity; electrical; mechanical; cu-; grain; mpa; electrical conductivity; aging; precipitation; phase; mechanical properties; tensile; phases	This study assesses the oxidation behavior of thermally stable nanocrystalline (NC) copper (Cu) alloys with varying tantalum (Ta) content. The aim was to investigate the oxidation resistance of nanograined materials using dynamic and isothermal gravimetric analysis, along with cross-sectional examinations. The results indicate that grain refinement (with grain sizes < 100 nm) and the addition of tantalum significantly enhance the oxidation resistance of these alloys. Specifically, the parabolic rate constants for the NC Cu-Ta alloy are reduced to half that of pure NC copper. Furthermore, oxide scale analysis revealed the presence of copper oxide and its dependence on solute concentration. The selective oxidation of tantalum was identified as the key factor contributing to the enhanced high-temperature oxidation resistance of these alloys, with NC Cu-3 at% Ta demonstrating superior performance. In conclusion, the improved oxidation resistance of Cu-based NC alloys broadens its potential use in various advanced applications, including high-temperature very large-scale integration processes.
10.1016-j.jallcom.2024.178402	14	strength; properties; conductivity; electrical; mechanical; cu-; grain; mpa; electrical conductivity; aging; precipitation; phase; mechanical properties; tensile; phases	This study integrates experimental analysis with molecular dynamics (MD) simulations to provide an in-depth exploration of the dynamic evolution of Pb-rich secondary phases (PSPs) in Cu-Pb alloys, focusing on the impact of different PSP morphologies on tribological performance. Cu-Pb alloy samples with precise atomic ratios were prepared, and the distinct morphological characteristics of network-structured and globular PSPs were captured using advanced microstructural characterization techniques. Leveraging the experimental data, MD models were developed: a Voronoi diagram and random seed algorithm were employed to construct the simulation model for network-structured PSPs, while custom MATLAB programming generated random radii and spatial distributions to model the globular PSPs. The friction simulations revealed that Cu-Pb alloys with network-structured PSPs (N-Alloy) exhibited poor self-lubricating performance, accompanied by severe wear and stick-slip behavior, whereas globular PSPs in Cu-Pb alloys (G-Alloy) significantly mitigated these issues, demonstrating superior lubrication characteristics. The strong agreement between simulation and experimental results underscores the critical role of PSP morphology in lubricating film formation and tribological performance. This method offers a systematic framework for analyzing microstructure-performance correlations, providing key insights into the optimization and application of alloys across a range of material systems.
10.1016-j.jallcom.2024.178411	5	materials; thermal; heat; properties; material; welding; sintering; fusion; strength; laser; heat sink; thermal conductivity; mechanical; sink; manufacturing	Tungsten-copper (W-Cu) composites have a wide range of engineering applications, from arc-resistant electrodes and high-voltage electrical contacts to heat sinks for integrated circuits and plasma-facing components for fusion reactors. They combine high corrosion and erosion resistance, very good thermal and electrical conductivity, low thermal expansion, with good mechanical properties. However, the fabrication of such materials is limited in terms of shape complexity and the internal distribution of the individual phases. Furthermore, the dissimilar thermo-mechanical properties (melting temperature, thermal conductivity, coefficient of thermal expansion) of the constituent phases impose severe constraints on the fabrication and use of W-Cu composites. To overcome the challenges of component design and enable greater freedom in terms of composition, W-Cu composites were produced by a combination of additive manufacturing and liquid-melt infiltration (LMI). Porous W-lattice structures were manufactured by laser powder-bed fusion (LPBF) followed by infiltration with molten Cu. A series of composites was produced with Cu contents from 3 to 75 vol% and evaluated in terms of thermal, electrical, and mechanical properties. The LPBF-LMI W-Cu composites exhibited comparable thermo-mechanical properties to W-Cu materials manufactured using powder-metallurgical processing, but with an expanded composition range and shape complexity. Lower thermal expansion coefficients (4.5-5.8 x 10-6 K- 1) and an improved thermal stability of the Young's modulus, only a 27-33 GPa decline in the range 27-827 degrees C, were observed for all the compositions, which was ascribed to the W-phase connectivity in all the W-Cu composites, independent of the volume fraction of Cu.
10.1016-j.jallcom.2024.178430	-1		Effects of content ratio of Cr and Zr on a non-vacuum smelted and one-pass hot and cold extruded Cu-Cr-Zr-RE alloy were investigated. Ultrafine grains, high density of dislocations and nano-precipitates were obtained after solidification with high cooling rate, hot extruding, solid solution, cold extruding and aging at as high as 500 degrees C for 1.8 h . The interaction of the above structures gave the alloy highest strength of similar to 700 MPa and conductivity of similar to 70 %IACS after 425 degrees C x 1.8 h aging. Increasing the Zr content to 0.24 wt% led to micro-segregation in the as- cast and hot-extruded alloys, resulting in uneven grain distribution after extrusion. The atoms' redistribution because of restoring during aging weakened their restriction on grain boundaries/sub-boundaries and made the distribution of grains uneven again. Because both Cr and Cu4Cr were precipitated and the growth of Cr was restricted by Zr with increment of Zr content under low-temperature aging, the nano-precipitates and high density of dislocations gave the alloy with highest Zr content highest strength . However, under high-temperature aging, the uneven microstructure and coarsened precipitates induced faster decrement of dislocations' density and strength as a result. The low conductivity in the low-temperature aged alloys was mainly caused by nano- precipitates and residual solutes in copper matrix. Conductivity was reduced by oxides brought by high content of Zr when precipitation during aging was insufficient.
10.1016-j.jallcom.2025.178452	14	strength; properties; conductivity; electrical; mechanical; cu-; grain; mpa; electrical conductivity; aging; precipitation; phase; mechanical properties; tensile; phases	In this research, Cu-Fe alloys with Fe compositions of 5, 10, 20, and 30 % were successfully fabricated using a novel spray-forming method and followed by cold rolling. The impacts of varying Fe compositions on solidification behavior, microstructure evolution, and mechanical characteristics were systematically investigated using various analytical methods, including OM, EPMA, XRD, SEM, EBSD, and TEM. The findings demonstrate that the Fe particles of the spray-formed Cu-Fe alloys with all components exhibit a fine and uniform distribution within the Cu matrix. With the increase in Fe compositions, the average grain diameter of the Cu matrix is obviously refined. The deformation behavior and the reinforcement mechanisms of Cu-Fe alloys with different Fe compositions during cold rolling were also explored. After cold rolling, Cu grains and Fe grains were distinctly refined and stretched into fibers in the rolling direction. The extent of Fe fibers became more pronounced as the Fe composition. The Cu matrix formed strong copper and brass textures. The strength of the spray-formed Cu-Fe alloy after cold rolling increased as the Fe composition increased. The enhanced strengthening effect of the alloy is predominantly attributable to a synergistic combination of high dislocation density within the Cu matrix, grain refinement, and Fe grain fibrillation. Furthermore, the strengthening mechanism of the spray-forming Cu-Fe alloy after cold rolling aligns with the Hall-Petch relationship. The research lays a solid foundation for the preparation and industrial production of Cu-Fe alloys with high Fe compositions.
10.1016-j.jallcom.2025.178508	15	aging; strength; conductivity; electrical conductivity; electrical; mpa; treatment; strengthening; degrees; cu-; cold; precipitation; tensile strength; tensile; iacs	In the aging process of the Cu-Ni-Sn alloy, various precipitate transformations can be observed in detail. The peak-aged alloy is strengthened by the DO22 ordered structure, while in the over-aged alloy, the precipitates are completely transformed into discontinuous precipitates. In this study, the Cu-9Ni-6Sn alloys aged for different times were subjected to severe plastic deformation to obtain two types of Cu-9Ni-6Sn alloy wires: peak-aged strengthening (S1) and over-aged strengthening (S2). S1 wires exhibit higher tensile strength and lower electrical conductivity, up to 1385 MPa, 11.1 %IACS, while S2 has lower strength and higher electrical conductivity, about 1178 MPa, 25.0 %IACS. The softening temperature of the S2 wire is around 400 degrees C, which is better than the 300 degrees C of the S1 wire. The decrease in dislocation density and the growth of gamma phases lead to the annealing softening of the two types of wires. Compared to S1 wires, the nanofibrous discontinuous precipitates in S2 wires can retard the spheroidization of precipitates and static recrystallization, thus hindering the occurrence of softening.
10.1016-j.jallcom.2025.178569	15	aging; strength; conductivity; electrical conductivity; electrical; mpa; treatment; strengthening; degrees; cu-; cold; precipitation; tensile strength; tensile; iacs	The Cu-15Ni-8Sn alloy can achieve ultra-high strength through heat treatment processes, but the significant reduction in its ductility limits its wider applications. How to synergistically enhance the strength and ductility of this alloy is a hot research topic. In this study, the industrial Cu-15Ni-8Sn alloy was taken as the research object, and the changes in alloy grain characteristics and mechanical properties under different cumulative deformations were compared by multi-pass rotary swaging deformation of the solution-state Cu-15Ni-8Sn alloy followed by aging heat treatment with different holding times. The evolution of phase structures in the rotary-swaged Cu15Ni-8Sn alloy during the aging process was investigated. The synergy mechanism of rotary swaging and aging process on the strength and ductility of the alloy was revealed. The results showed that with the increase of rotary swaging deformation, the Cu-15Ni-8Sn alloy grains gradually elongates until they tended to be fibrous, and the grain texture changed from random distribution to <111> and <100> distribution. Rotary swaging deformation promotes the precipitation of the D022 ordered phase. After 75 % rotary swaging deformation and aging treatment at 400 degrees C for 60 min, the ultimate tensile strength and elongation of the Cu-15Ni-8Sn alloy reaches 1405 MPa and 6.1 %, respectively. The characteristics of high strain rate and large cumulative deformation of rotary swaging activate more slip systems and twin systems, improve the strengthening efficiency, and are conducive to uniform deformation and plasticity of metals. Rotary swaging deformation promotes the formation of D022 ordered phase during aging, and the interaction between nanoscale precipitates and dislocations produces a significant precipitation strengthening effect. Based on the above synergistic effects, the results of this paper realize the simultaneous improvement of strength and plasticity of Cu-15Ni-8Sn alloy. This optimization of comprehensive mechanical properties makes the alloy very suitable for use in complex environments requiring high strength and good machining capability.
10.1016-j.jallcom.2025.178629	-1		Tailoring the subtle microstructure has been a major challenge for developing the advanced W-Cu composites with a high electric conductivity and mechanical properties. Herein, a strategy for oscillating pressure sintering was proposed to achieve the fine control of Cu-network structure in the W@20Cu composites with Cu-coated W powders. Based on numerical simulation, the forming reason and evolution process of the rich-Cu region in the hot-pressure sintering process of W@20Cu composites were revealed to screen out the feasible loading scheme for overcoming the mechanical interlock of contacted particles. Through sintering experiment, the relationship between the sintering processes and the mechanical properties of W@20Cu composites was systematically evaluated to find the optimal process system of oscillating pressure sintering. The sintered W@20Cu composites after oscillating compaction of 50 -> 10 MPa exhibited an ultra-low enrichment rate of Cu of 7.2 % and a high relative density of 99.36 %, drastically outperforming conventional constant pressure sintering technologies. The tensile and compressive strength of oscillating pressure sintered W@20Cu composites can reach 350 MPa and 785 MPa, which are 9.4 % and 20.96 % higher than that of the sintered sample after uniform loading (321 MPa and 649 MPa), respectively. This study provides a practical theoretical guidance for managing the microsegregation and particle rearrangement of the W-Cu composites based on the process route of powder metallurgy.
10.1016-j.jallcom.2025.178650	-1		The multi-level heterostructured Cu-Ni-Al-Sn-Si (Co-free alloy) and Cu-Ni-Al-Sn-Si-Co alloys (Co-containing alloy) are successfully fabricated and systematically investigated. A strength-ductility trade-off is achieved in both alloys, particularly in the Co-containing alloy, which shows 1184 MPa of ultimate tensile strength, 1076 MPa of yield strength, and 9.2 % of elongation, respectively, exceeding those reported in the literature and commercial Cu-Ni-Al alloys. The microstructural characterization reveals that the non-uniform fine grain distribution and lamellar γ′-(Cu, Ni)3Al phases are obtained in the alloys. The first-principal calculations confirm that Co slightly affects the precipitation of the γ′-(Cu, Ni)3Al phase and promoting its coarsening due to the reducing absolute values of formation energies (Ef) and cohesive energy (Eb), and meanwhile, it accelerates the process of recrystallization due to the decreasing stacking fault energy. Deformation characters investigations reveal that the combination of massive stacking-faults, Lomer-Cottrell locks and dynamically reinforced HDI hardening contribute to the excellent ductility and work-hardening capacity at high-level strength in Cocontaining alloy. This study provides theoretical guidance and experimental data for the research and development of Cu-Ni-Al alloy, and provides a new approach for composition design and microstructure control of high-strength, high-plasticity, and corrosion-resistant copper alloys.
10.1016-j.jallcom.2025.178719	14	strength; properties; conductivity; electrical; mechanical; cu-; grain; mpa; electrical conductivity; aging; precipitation; phase; mechanical properties; tensile; phases	Unidirectional Porous Materials (UPMs), characterized by their parallel unit cells aligning to the axis and high aspect ratios, exhibit remarkable thermal conductivity and superior energy absorption capabilities, rendering them ideally suited for applications as casings for reactive fragment. To mitigate the structural inhomogeneity of the unit cell prevalent in pure Cu UPMs fabricated by plastic deformation, a cold drawing method was employed to synthesize a uniformly structured Cu-Sn UPM. Sintering at 300 degrees C for 0.5 h effectively eliminated the interfacial disparities between Sn. Subsequently, the impact of heat treatment duration at 200 degrees C on the uniaxial compressive properties of the Cu-Sn UPM was examined. It was observed that heat treatment at this temperature can augment the densification strain of the UPM without diminishing its strength, consequently boosting its energy absorption capacity during the plateau phase. Specifically, a 16-h regimen at 200 degrees C resulted in a 20 % enhancement in densification strain and nearly a 30 % escalation in energy absorption. However, prolonging the heat treatment beyond 16 h attenuated the increments in densification strain and energy absorption significantly. This reduction is attributed to the thickening of the Cu6Sn5 and Cu3Sn intermetallic compounds (IMCs) formed, which modified the compression-induced deformation mechanism of the cell walls.
10.1016-j.jallcom.2025.178770	14	strength; properties; conductivity; electrical; mechanical; cu-; grain; mpa; electrical conductivity; aging; precipitation; phase; mechanical properties; tensile; phases	Compositionally graded Cu-Fe alloys (0-50 wt% Fe) were fabricated using laser powder bed fusion (LPBF) technique to investigate the effects of Fe on porosity, microstructure, and electrical conductivity. Variations in porosity, influenced by Fe content, build height, and thermal history, were assessed using micro-X-ray computed tomography (XCT) and optical microscopy. It was demonstrated that incorporating more than similar to 5 wt% Fe in Cu improves the laser absorptivity of Cu substantially, thereby reducing lack-of-fusion pores in the fabricated specimens and enabling reliable fabrication of Cu alloys. Detailed microstructural analysis revealed the presence of fine Fe spheres, which contribute to grain refinement, with their influence depending on Fe content. Electrical conductivity and hardness were evaluated prior to and after heat treatment, indicating that increasing Fe content leads to higher hardness but lower electrical conductivity. Fe content in the range of similar to 5-15.1 wt% provides a good combination of printability, mechanical properties, and electrical conductivity.
10.1016-j.jallcom.2025.178783	-1		The CrCoNiFe high entropy alloy particle reinforced Cu matrix composites with up to 20 wt% reinforcements were successfully fabricated through rapid electrical current hot-pressed sintering. The results demonstrate that the addition of CrCoNiFe particles into Cu matrix can effectively refine the grain size of Cu matrix and benefits to form a metallurgical bonding interfacial diffusion layer (CrCoNiFeCux), which ultimately improves the strength-ductility synergy of the CrCoNiFe/Cu composites. The relative density increases from 97.3 % to 99.1 %, the microhardness increases from 60.3 HV0.1 to 113.8 HV0.1, the ultimate tensile strength increases from 208 MPa to 335 MPa and the softening temperature improves from 660 degrees C to 730 degrees C but electrical conductivity decreases from 97.8 % to 32.3 % IACS when the CrCoNiFe reinforcement content in the composites increased from 0 to 20 wt%. The as-produced CrCoNiFe/Cu composites possess good ductility with tensile elongations of > 30 %. The strengthening mechanism analysis reveals that the geometrically necessary dislocations strengthening mechanism contribute predominantly to the improvement of yield strength .
10.1016-j.jallcom.2025.178796	-1		Porous copper with adjustable structures was successfully prepared from a low-cost H62 Cu-Zn alloy using onestep chemical/electrochemical dealloying method. The effects of dealloying conditions on the porous microstructure and dealloying mechanism were investigated. The results show that during chemical dealloying, the dealloying mechanism remains constant, involving only atomic diffusion and dissolution. This leads to a consistent bicontinuous porous structure across all chemical dealloying conditions. In contrast, applying additional potentials not only accelerates the atomic diffusion and dissolution, but also shifts the dealloying mechanism from asynchronous corrosion to galvanic corrosion, and forms various porous structures. Notably, hierarchical porous Cu is only fabricated by precisely controlling the dealloying potential at intermediate levels around 0.2 V. The finally dealloying morphology arises from the competition between diffusion and dissolution, and similar porous morphologies are achieved by keeping Ds at comparable levels. The nano-hardness and elasticity modulus of all dealloyed H62 alloys are reduced depending on their structure. However, the prepared bimodal porous Cu exhibits a higher nano-hardness of 0.28 +/- 0.04 GPa compared to most reported porous metals, which is beneficial for its service performance and lifespan.
10.1016-j.jallcom.2025.178887	-1		Synergistic improvement between the mechanical properties and wear resistance of Cu-Ni-Sn alloys is critical for extending the service life of materials in practical applications. In this study, Cu-12.5Ni-5Sn-xZr alloys (x = 0, 0.5, 1.0, and 1.5 wt%) were prepared by spark plasma sintering (SPS). Subsequently, the effects of Zr addition on the microstructure, mechanical, and high temperature tribological properties were systematically investigated. We found that Zr addition significantly refined the alloy grains and allowed the gamma-phase to more easily precipitate with needle-like or particulate-like shapes. When 1.0 wt% Zr was added, the formation of nano-scale Ni4SnZr phase inhibited discontinuous precipitation (DP) nucleation and reduced the growth rate. Meanwhile, the hardness and yield strength reached aging peaks of 326.8 HB and 669.5 MPa, respectively, which were approximately 30 % and 43 % higher than without Zr. This improvement was mainly attributed to grain refinement, nano-precipitation strengthening and the inhibition of DP. Furthermore, the addition of 1.0 wt% Zr could improve the tribological properties of the matrix alloy, especially the wear rate reached an order of magnitude of 9.28 x 10_6 mm3/N & sdot;m at room temperature. From room temperature to 500 degrees C, the decrease in friction coefficient of the alloys was mainly due to the formation of metal oxides, whereas the increase in wear rate was mainly the decrease in mechanical properties and severe oxidation at high temperature.
10.1016-j.jallcom.2025.178978	14	strength; properties; conductivity; electrical; mechanical; cu-; grain; mpa; electrical conductivity; aging; precipitation; phase; mechanical properties; tensile; phases	Cu-Ni-Co-Si-Mg-xCr alloys (where x = 0, 0.15, 0.32, or 0.4 wt%) were prepared, and stress relaxation tests were conducted at 50 degrees C, 100 degrees C, and 150 degrees C for 48 h . The results showed that the addition of Cr considerably enhanced the stress relaxation resistance of the Cu-Ni-Co-Si-Mg alloys at 150 degrees C. Compared with that of the 0 % Cr alloy, the stress relaxation resistance improved by 29.7 %, 22.6 %, and 23.3 % as the Cr content increased. To understand the underlying mechanisms, the microstructure of the alloys, the morphology of the precipitates, and the dislocation density before and after the stress relaxation tests were analyzed via electron backscatter diffraction (EBSD), transmission electron microscopy (TEM), and X-ray diffraction (XRD). The differences in precipitates and grain size were the primary reasons for the variations in stress relaxation resistance. The delta-(Ni, Co)2Si phase constitutes the main precipitate in the alloys. Adding 0.15 % Cr can produce Cr precipitates with non-coherent orientation relationship with Cu matrix, which are effective in pinning dislocations. Moreover, the addition of Cr increased the grain size, which reduced the preferential orientation of the grains and the activation of the dislocation sources during microplastic deformation. Both factors suppressed dislocation movement, which is the fundamental reason for the enhanced stress relaxation resistance of the Cu-Ni-Co-Si-Mg-0.15Cr alloy.
10.1016-j.jallcom.2025.179292	14	strength; properties; conductivity; electrical; mechanical; cu-; grain; mpa; electrical conductivity; aging; precipitation; phase; mechanical properties; tensile; phases	This study investigates the mechanism by which the microstructure of cold-rolled Cu-Ni-Co-Si alloys influences the precipitation strengthening and recrystallization processes during aging treatment. The cold-rolling reductions applied were 30 %, 50 %, 70 %, and 80 %, with aging temperatures of 450 degrees C, 500 degrees C, and 550 degrees C, and holding times ranging from 60 to 480 min. The results indicate that with the increase in cold rolling reduction, a significant accumulation of dislocations occurs within the matrix, leading to an increase in texture density. Additionally, under stress dominance, the alloy structure formed after cold rolling exhibits a large number of shear bands and solute segregation gradients, which also rise with the increase in cold rolling reduction. Microstructural observations after aging reveal the precipitation of nanoscale S-(Ni,Co)2Si strengthening phases during aging, and ion spectrum confirm the stability of S-(Ni,Co)2Si during the aging process. The S-(Ni,Co)2Si phase interacts with dislocations during aging and couples with sub-grain boundaries, improving the mechanical properties of the alloy. The grains undergo varying degrees of recrystallization, with both continuous static recrystallization (CSRX) and discontinuous static recrystallization (DSRX) occurring during the process. For the sample with 80 % cold-rolling reduction, the hardness after peak aging at 450 degrees C, 500 degrees C, and 550 degrees C were 255.3 HV, 284.8 HV, and 271.7 HV, respectively. After aging at 500 degrees C for 60 min, the dislocation cells in the matrix transform into subgrains. The distribution of S-(Ni,Co)2Si phases along the sub-grain boundaries and high-density dislocations inhibits the recrystallization process, resulting in the alloy achieving a conductivity of 38.88 % IACS and a tensile strength of 798.38 MPa.
10.1016-j.jallcom.2025.179325	-1		The large number of applications of Cu-Ni alloys in the marine field and the prevalence of cavitation erosion (CE) necessitate a thorough examination and improvement of the CE characterization of Cu-Ni alloys. In this study, Cu-Ni alloy cladding layers were prepared by laser cladding technology and compared with the Cu-Ni casting alloy of the same composition. It was found that the grains of the Cu-Ni cladding layer were more uniform, with an average size of only 5 mu m, while the grain size of the casting alloy varied greatly, ranging from approximately 20 to 40 mu m. The cladding layer with fine grains and uniform structure reduced the weight loss of the Cu-Ni sample by 16.8 % during the CE stabilization period. Additionally, the influence of Ni content on the CE resistance of Cu-Ni alloy cladding layers was investigated. The results showed that during the CE stabilization period, the average weight loss rates of the three Cu-Ni cladding layers (Ni25Cu, Ni35Cu, and Ni45Cu) were 81.07 mg/h, 77.25 mg/h and 61.21 mg/h, respectively. With the increase in Ni content, the weight loss at each stage of CE decreased. The doping of Ni into the Cu lattice caused lattice distortion, promoted dislocation formation and grain refinement, thereby increasing the surface hardness. That made it more difficult for bubbles to destroy the surface, and limited the internal expansion of defects caused by CE.
10.1016-j.jallcom.2025.179542	14	strength; properties; conductivity; electrical; mechanical; cu-; grain; mpa; electrical conductivity; aging; precipitation; phase; mechanical properties; tensile; phases	The size of the reinforcing particles is pivotal in defining the mechanical properties of particulate-reinforced copper matrix composites (PRCMCs). In this study, Aluminum (Al) bronze composites incorporating TiB2 particles of varying sizes were synthesized using both in-situ and precursor methods to achieve precise control over their microstructure and enhance their performance. The effects of the TiB2 particle size on the microstructure, mechanical properties, and tribological performances of the Al bronze composites were systematically compared and investigated. The results demonstrate that composites prepared using the Al-TiB2 precursor method feature significantly finer TiB2 particles at the nanoscale (0.85 mu m), alongside more pronounced grain refinement (0.4 mu m), leading to a uniformly refined microstructure. The as-rolled precursor composites exhibit markedly superior yield strength (676 MPa), ultimate tensile strength (792 MPa), and fracture elongation (7.3 %), with grain boundary strengthening and dislocation strengthening identified as the key mechanisms. In comparison to the asrolled in-situ composites, the as-rolled precursor composites demonstrate enhanced wear resistance, with reductions in the average coefficient of friction and wear rate of 23.4 % and 58.8 %, respectively. The wear mechanism of the as-rolled precursor composites transitions from surface fatigue and adhesive wear in dry sliding to predominantly abrasive wear. These findings provide new insights into the development of Cu matrix composites with enhanced mechanical properties and superior wear resistance.
10.1016-j.jallcom.2025.179547	-1		Titanium alloy is widely used in marine vessels and acoustic sounding equipment, but its application in ocean engineering is limited by marine biofouling. This can be addressed by applying a copper layer with strong adhesion and antimicrobial properties. However, integrating titanium and copper is challenging, and it is necessary to consider whether this combination will affect the sound transmission performance of acoustic sounding equipment when applied to its outer shell. In this study, pure Cu and Cu-Sn alloy (95 wt%Cu+5 wt%Sn) cladding layers were successfully synthesized on titanium alloy (TA3) surface using laser cladding with a 12000 W fiber laser. The process parameters included a laser scanning speed of 83.3-100.0 mm/s and a laser power of 1600-1820 W. The results show that the addition of Sn can improve the wettability between copper alloy powder and titanium alloy substrate. The bond strength of the Cu-Sn alloy cladding layer is 204.54 MPa, an 87.15 % increase compared to pure Cu (109.29 MPa). The quality of the cladding layer formation and the metallurgical bonding property were enhanced due to reduction of the formation of dendrite Ti-Cu brittle phases and the refined grain structure. Cu-Sn alloy cladding layers outperform pure Cu in sound transmission, with both coefficients exceeding 0.75. Laser cladding Cu-Sn alloy is more advantageous, which provides a novel strategy for the preparation of antifouling copper layers on titanium alloys applied to marine vessels and acoustic sounding equipment.
10.1016-j.jallcom.2025.179649	14	strength; properties; conductivity; electrical; mechanical; cu-; grain; mpa; electrical conductivity; aging; precipitation; phase; mechanical properties; tensile; phases	Micro-pores healing is crucial for enhancing the properties of cold-sprayed coatings, especially in composite coatings involving hard particles, where removing micro-pores remains challenging. Here, we introduce a novel strategy, ultrasonic micro-healing (UMH) treatment, which enables rapid micro-pores healing in cold sprayed CuCrZr-W coating through ultrasonic vibration-induced local plastic deformation. In the as-sprayed coating, crescent-shaped micro-pores are often observed beneath W particles, accompanied by amorphous layer at the W/ CuCrZr interface. During UMH process, the micro-pore size contracts from several micrometers to tens of nanometers within 1 s, resulting in a 67 % decrease in coating porosity and a 24 % increase in bonding strength with the substrate. The rapid healing mechanism is governed by local plastic deformation around micro-pores, in which temperature rise and dynamic recrystallization of Cu grains near micro-pores facilitate this process. Finally, the healing process complete by the re-connection of the amorphous phase via atomic diffusion.
10.1016-j.jallcom.2025.179740	6	grain; deformation; strain; strength; dislocation; cu-; tensile; size; ecap; grain size; sfe; ductility; hardening; high; stress	Gradient-structured (GS) metallics materials exhibit superior mechanical properties due to the existence of mechanical incompatibility. However, the extra strengthening induced by mechanical incompatibility and the deformation behavior of GS Cu alloys with different stack fault energy (SFE) during tensile strain are still unclear. In this study, GS Cu and Cu-Al (2.2 wt%, 6.9 wt%) alloys with SFE of 78 mJ/m2, 28 mJ/m2 and 6 mJ/m2 (2.2 wt% and 6.9 wt%, respectively) were prepared by the surface mechanical attrition treatment (SMAT). It was found that gradient deformation twins were dominated in the GS Cu-6.9Al sample with the lowest SFE, while gradient dislocations were formed in the GS Cu and Cu-2.2Al samples, resulting in the highest degree of mechanical incompatibility in terms of the ratio of the hardness increment to thickness of gradient structure layer in the GS Cu-6.9Al sample. The tensile properties showed that the GS Cu-6.9Al sample with the highest mechanical incompatibility exhibited a superior combination of strength and ductility, compared with the GS Cu and Cu-2.2 Al samples. Furthermore, the GS Cu-6.9Al sample with the lowest SFE showed the highest extra strengthening and the most obvious HDI strengthening. In addition, more dispersed and stable strain bands were observed in the GS Cu-6.9Al sample, meanwhile producing the most obvious strain gradient, which corporately improved strength while maintaining good ductility. This work provides a meaning insight on understanding strengthening and deformed behavior of gradient structure Cu alloys with different SFE.
10.1016-j.jallcom.2025.179845	-1		Semietching is the most advanced preparation method for integrated circuit lead frames and has high requirements for the etching behavior of copper alloys. The enhancement of the semietching behavior of the Cu-Cr-Zr-Sn-Zn-Mg alloy via the coupling control of grain boundaries, phases, dislocations, residual stress, and texture distribution was studied. The result show that the etched sample surface exhibits a lower roughness when the matrix has a smaller grain size, finer precipitated phases, larger number of lattice defects, and a broader distribution of copper, brass, S, and R textures. The corrosion mechanism of the solid solution and cold rolling deformation samples is the composite corrosion of grain boundaries and lattice distortion. The matrix does not contain areas with low kernel average misorientation (KAM) values, and the roughness of the semietched surface is lower than 0.4 mu m, when KAM is between 1.0 and 1.2. The corrosion mechanism of the aging and cold rolling deformation samples mainly involves the grain boundaries, precipitates, dislocations, and texture distribution. The differences in the corrosion rates of each region are major factors that affect the morphology and roughness of the etched corrosion surface. The sample subjected to 80 % cold rolling and subsequent 40 % cold rolling deformation after aging for 4 h at 440 degrees C possesses an average grain size of 3.8 mu m, a hardness of 158 HV, and an electrical conductivity of 79.7 % IACS, exhibiting an optimal surface roughness(Sa) of 0.21 mu m.
10.1016-j.jallcom.2025.179853	-1		Cu-Nb composites (10-20 wt%Nb) are promising conductors for microsecond range high-field pulsed magnets (inductors), owing to their stable high strength and conductivity. However, the superior performance of these composites is mainly achieved by means of severe plastic deformation of the alloy, e.g. by cold drawing, thereby yielding maximum strength and conductivity along the drawing direction. Here, bulk Cu-Nb composites were developed by processing two types of powders: the first one was obtained by ball milling of heavily drawn Cu-18 %Nb wire, and the second one by electrical co-explosion of Cu and Nb wires (25 wt%Nb). The bulk materials were produced by powder dynamic compaction and subsequent sintering at 650-850 degrees C, without the application of strain post-hardening. The sintered materials were examined by X-ray diffraction, scanning electron and optical microscopy. The annealing effect on the electrical conductivity and mechanical properties of the materials has been investigated. The bulk composites, obtained by sintering of compacted nanocrystalline powders at 780 f 30 degrees C for 1-3 hours, have shown a combination of an ultimate tensile strength of 900 f 40 MPa and a resistivity of 3.8 f 0.4 mu Ohm & sdot;cm. The crystallite size of the composite phases did not exceed 90 nm. High density of grain boundaries gives the main contribution to the strength and resistivity besides the dispersion and solid solution strengthening. Both of the developed materials have demonstrated a higher thermal stability, by 50-100 degrees C, in comparison to the wire due to in situ dispersion hardening by niobium-based nanoparticles formed during the sintering.
10.1016-j.jallcom.2025.179875	14	strength; properties; conductivity; electrical; mechanical; cu-; grain; mpa; electrical conductivity; aging; precipitation; phase; mechanical properties; tensile; phases	This study examined the surface oxidation behavior of Cu64Zr36 metallic glass powders in ambient conditions, with a particular focus on the growth of surface native oxides at the atomic level. After 30 days of exposure to atmospheric conditions, the formation of native oxide films on the metallic glass powder particles is observed, with thicknesses varying from approximately 900 nm to 2000 nm. These films are significantly thicker-by several orders of magnitude-compared to those typically found on bulk metals and alloys. The native oxide films exhibit a complex multilayered structure, compromising conical Cu2O nanocrystals at the surface, a continuous outer layer of Cu/Cu2O, and an inner layer consisting of lamellar structures with crystalline Cu/Cu2O networks embedded within an amorphous-ZrO2/m-ZrO2 matrix. The presence of these thick, hard, and multilayered native oxide films is anticipated to significantly impact the interfacial bonding of adjacent powder particles during processes such as additive manufacturing and powder metallurgy.
10.1016-j.jallcom.2025.179938	-1		The poor hot workability of Cu-Ti alloys (Ti content > 4 wt%) severely restricts their wide applications. In this work, we report on a study of the effect of hot strain on the dynamic recrystallization (DRX), precipitation and coordinated deformation behaviors of Cu-4.3 wt% alloy. Our results show that based on the obtained constitutive equation and thermal activation energies, the corresponding workability maps of alloy can be established and used to solve the difficulty in hot working. The complex interactions that occur between dislocation and precipitates lead to the differences in DRX and precipitation for the changed strain rates and temperatures. Our results provide fundamental insight into the DRX, precipitation and coordinated deformation in high Ti concentration of Cu-Ti alloys with poor deformability, as a function of hot strain.
10.1016-j.jallcom.2025.179979	-1		The microstructural evolution and precipitation behavior in the Cu-1.5Ni-0.25 P alloy during aging at temperatures in the range of 350-550 degrees C are investigated. Based on a microstructural analysis, the strengthening contributions of the precipitates and the grain boundaries are quantitatively calculated. The results show that three types of nanoprecipitates are formed in the aged Cu-1.5Ni-0.25 P alloys, including the Ni2P phase (formed at 350, 450 and 550 degrees C), the Ni12P5 phase (formed at 450 and 550 degrees C) and the Ni3P phase (formed at 550 degrees C). The nanoprecipitates formed at 350 and 450 degrees C have a spherical morphology due to the small precipitate size. In the Cu-1.5Ni-0.25 P alloy, a transition from a spherical to a cuboid shape occurs during aging at 550 degrees C, as the precipitates become significantly coarser. With a further increase in precipitate size, the Ni2P and Ni3P precipitates preferentially grow along the direction with a low degree of interfacial misfit and gradually evolve from a cuboidal to a rod-shaped or lath-shaped morphology. However, the Ni12P5 nanoprecipitates remain in a cuboidal morphology even when the precipitates grow to 27 nm due to the low degree of lattice mismatch anisotropy. In addition, the precipitate strengthening effect in the aged Cu-1.5Ni-0.25 P alloy is mainly dominated by the Orowan bypass mechanism since the precipitates are semi-coherent with the Cu matrix. Precipitate strengthening is much stronger than grain boundary strengthening, which is the predominant strengthening mechanism in the aged samples. After aging at 450 degrees C for 36 h, a relatively high volume fraction of nanoprecipitates (similar to 1.4 vol%) and a small precipitate size are achieved in the Cu-1.5Ni-0.25 P alloy, resulting in a precipitation strengthening contribution of similar to 299 MPa. The contribution of precipitation strengthening to the overall strength increase exceeds 85 % in the aged Cu-1.5Ni-0.25 P alloy. In addition, the Cu-1.5Ni-0.25 P alloy aged at a higher temperature has a higher electrical conductivity for the same aging time, which is mainly due to the lower concentration of dissolved atoms in the Cu matrix.
10.1016-j.jallcom.2025.179981	-1		Pure W powders with initial particle sizes of 100 nm, 500 nm, and 1 mu m and pure Cu powder were utilized to prepare Cu-10W composites through ball-milling and vacuum spark plasma sintering (SPS) techniques. W particle size was thoroughly studied for its effect on the microstructure and mechanical properties of Cu-10W composites. Results display that, as the W particle size decreases, the average grain size of Cu-10W composites reduces from 0.97 mu m to 0.54 mu m, and the hardness and tensile strength of samples gradually increase. Specifically, the hardness of the Cu-10W composites with 100 nm W particles reaches 2.002 GPa, and the tensile strength achieves 324 MPa, respectively, which are 14.4 % and 70.53 % higher than that of Cu-10W composite with 1 mu m W particles. Under the synergistic action of fine grain strengthening and dispersion strengthening, the pinning effect of W particles was enhanced, improving the properties of Cu-10W composites. This work can provide a basis for how to select the appropriate W particle size to prepare high-performance Cu-10W composites.
10.1016-j.jallcom.2025.179983	-1		In this study, the effects of He and N2 carrier gases on the microstructure, mechanical properties, softening temperature, and electrical conductivity of cold-sprayed alumina dispersion-strengthened copper (ADS Cu) were investigated. Results indicate that the deposits prepared using He as the carrier gas are denser and less porous. In addition, most of the region in the deposits consists of ultrafine grains with a uniform grain structure. The cumulative effect of these microstructural features resulted in a microhardness and ultimate tensile strength of 204 HV and 550 MPa, respectively, for the deposits constructed using He as the carrier gas were 1.1 and 2.4 times those constructed using N2 as the carrier gas. Both deposits produced using He and N2 as carrier gases exhibited a softening temperature of 1203 K, demonstrating excellent high-temperature performance. Moreover, the electrical conductivity of He deposits is higher than that of N2 deposits, which is due to their low porosity. This study provides a theoretical basis for further understanding the effects of different carrier gases on the organization and mechanical properties of ADS Cu alloys.
10.1016-j.jallcom.2025.179998	-1		The development of copper alloys with balanced strength and plasticity across a wide temperature range remains a critical challenge for aerospace and power industries, The γ′-(Ni, Cu)3Al phase coherent precipitation strengthened Cu-Ni-Al ternary alloy shows excellent room and elevated-temperature tensile strength, but limited ductility. Herein, we propose a novel multi-component design strategy to achieve synergistic optimization of coherent γ′ precipitation and grain boundary engineering in a Cu-based alloy (Cu50Ni17.375Al9.375Co17Cr3.125Ti3.125B0.5 (at%)). The addition of Co, Cr, Ti, and B to reconfigure the γ′ phase into a thermally stable structure while utilizing the role of B in improving grain boundary strength and inhibiting diffusion of oxygen atoms along grain boundary. The results show that the yield strength, ultimate tensile strength and elongation of the alloy at room temperature reached approximately 1050 MPa, 1180 MPa and 9 %, respectively. At 700 degrees C and 800 degrees C, the tensile strengths reached approximately 380 MPa and 220 MPa respectively, and maintained approximately 3 % of elongation, realizing reasonable strength-elongation trade off compare to commercial heat-resistant Cu alloys and the reported Cu-Ni-Al ternary alloys with similar composition. The enhancement of mechanical properties at room temperature can primarily be attributed to the mechanical characteristics of the complex γ′ phase ((Ni, Co, Cu)3(Al, Cr, Ti)), the increase in unstable stacking fault energy, and the interstitial filling effect of the B element within the grains or at the grain boundaries. The improvement in mechanical properties at high temperatures is associated with the thermal stability of the multi-component γ′ phase and the addition of the B element, which plays an important role in the inhibition of oxygen diffusion, refinement of grain size, pinning effect of grain boundary. This study provides a new strategy for designing coherent precipitation-strengthened Cu alloys with tunable mechanical performance from ambient to extreme temperatures.
10.1016-j.jallcom.2025.180080	-1		An experimental study was conducted to investigate the improved ductility and strength of cold-rolled copper sheets. Its deformation mechanism at liquid nitrogen temperature (LNT) was elucidated. Tensile and bulging tests were conducted to comprehensively analyze the deformation behavior under uniaxial and complex stress states. The relationships between macroscopic deformation and microstructural evolution were quantitatively evaluated through scanning electron microscopy (SEM), electron backscattered diffraction (EBSD), and transmission electron microscopy (TEM). At LNT, the ductility of pure Cu increased by 72.2 % compared to room temperature (RT). The yield strength and tensile strength enhanced by 18.7 % and 56.6 %, respectively. The average limiting dome height (LDH) increased from 17.9 mm to 21.8 mm. These results indicated that pure Cu showed a synergistic enhancement of strength and ductility at LNT. Also, the work-hardening coefficient of pure Cu was found to be more dependent on temperature than on strain rate. In the biaxial stress state, the enhanced ductility at LNT was attributed to the reorientation of grains. Additionally, pure Cu exhibited an enhanced resistance to localized deformation. The increase in strength was due to a reduction in relative slip distance, but the significant increase in dislocation density, Peierls-Nabarro stress and strain hardening at LNT.
10.1016-j.jallcom.2025.180121	14	strength; properties; conductivity; electrical; mechanical; cu-; grain; mpa; electrical conductivity; aging; precipitation; phase; mechanical properties; tensile; phases	Although Cu-Zr alloys demonstrate excellent electrical conductivity and mechanical properties, their strengthening potential is constrained by two primary factors: the minimal lattice mismatch between the Cu5Zr phase and the matrix, which reduces interfacial strengthening effects, and the presence of eutectic Cu5Zr phase at grain boundaries, which compromises mechanical strength and limits practical applications. In this study, Cu-0.5Zr alloy was used as a prototype, and the semi-metallic element Si was added to form two types of CuxZrySiz ternary phases. Through thermodynamic calculation of phase diagram and density functional theory (DFT), we reveal that the structure and size of these phases are particularly sensitive to the content of Si. Thus, the second phase with different morphology physical properties can be formed. Our research discovers that adding 0.1 wt% Si to the Cu-0.5Zr alloy induces the formation of ductile micron-scale Zr3Cu4Si2 phase and strong nanoscale ZrCuSi phase. The yield strength of the alloy reaches 570 MPa, yet the elongation and the conductivity remain above 10 % and 76 % IACS, respectively. The incorporation of Si facilitates the formation of multi-scale reinforcing phases in the matrix and simultaneously suppresses the recrystallization-induced softening, thereby significantly enhancing the mechanical properties of the alloy. This study establishes a fundamental framework for the development of advanced materials with synergistic enhancement of strength and conductivity, offering new perspectives for future research in high-performance material design.
10.1016-j.jallcom.2025.180158	-1		Low-temperature aging significantly affects the mechanical properties and martensitic transformation temperatures of Cu-Al-Mn (CAM) alloys. In this study, X-ray absorption spectroscopy (XAS) and density functional theory (DFT) were used to investigate the local order changes in a CAM shape-memory alloy during lowtemperature aging treatment. The as-quenched CAM alloys were inhomogeneous, in which the average local Mn exhibited an L21-like structure and Cu predominantly occupied the first-nearest-neighbor positions around Al. Conversely, the Cu exhibited a D03-like local structure. During the 373 K aging treatment, the average local Mn atoms tended to form an L21 structure, and the arrangement of Mn atoms changed in two stages: formation of Mn-rich structures and reduction during 423 K aging treatment, whereas no significant change was observed for Al. Using XAS and magnetic measurements, phase separation was detected in the sample treated at 423 K for 120 min. This observation aligns well with the formation energy based on DFT calculations, which explains the transition from disordered to ordered structures during low-temperature aging driven by the aggregation and diffusion of Mn atoms with antipapal spin moments.
10.1016-j.jallcom.2025.180168	-1		Compositional segregation, microstructural inhomogeneity and insufficient wear-resistant are the primary challenges associated with the traditional smelting and casting of Cu-Ni-Si alloys. This study presented a powder metallurgy technique for preparing Ti3SiC2 MAX phase reinforced Cu-3.8Ni-1Si alloy with homogeneous composition and good comprehensive performance. The manipulation of solution and precipitation as well as the morphology modulation of delta-Ni2Si phases were achieved via Ti3SiC2 MAX phase and in-situ formed SiC whiskers. Nano-sized Ni2Si phase showed a coherent interface relationship with the alloy matrix, which hindered the climbing and sliding of dislocations. A mechanically mixed layer (MML) composed of Ti3SiC2 MAX phase, SiC whisker, and delta-Ni2Si phase were formed on the surface of tribological layer. Meanwhile, the synergistic effects among Ti3SiC2 MAX phase, SiC whisker, and delta-Ni2Si phase significantly improved the mechanical properties. Therefore, Ti3SiC2/Cu-Ni-Si composite has provided a promising candidate for applications requiring high strength and wear resistance in copper alloys.
10.1016-j.jallcom.2025.180265	-1		Due to the demanding operating conditions of high-power devices, efficient heat dissipation during packaging is essential. In this study, nanoporous Cu (NP-Cu) with high thermal conductivity (293.3 W/(mK)) was fabricated through co-electroplating Cu-Zn followed by dealloying. Analysis by transmission electron microscopy shows that the NP-Cu consists of nanocrystalline grains with a grain size of 50 nm, 15 % porosity, and its pore size was about 40 nm. The NP-Cu grains also contains nanotwins with a twin spacing of 5 nm. The results showed that using NP-Cu as an interlayer increased the bonding fractions and enabled successful bonding at lower temperatures and pressures. The NP-Cu possessed low yield strength, allowing it more adaptable to various levels of surface roughness and facilitating the bonding. Highly < 111 >-oriented NT-Cu was also applied to enhance bonding. The high-conformity combination of NP-Cu and NT-Cu created a bonding structure with both high thermal conductivity and good reliability, making it a potential thermal interface material (TIM) for high-power device packaging.
10.1016-j.jallcom.2025.180325	8	hot; deformation; strain; strain rate; dynamic; hot deformation; recrystallization; dynamic recrystallization; flow; rate; flow stress; compression; constitutive; degrees; stress	Thermal compression experiments were conducted on Cu-0.8Fe-0.2Cr alloys within a temperature range of 600-950 degrees C and at strain rates varying from 0.003 to 10 s(-1) to establish their constitutive equations. The results show that the thermal deformation activation energy of Cu-0.8Fe-0.2Cr alloy is 341.7 kJ/mol, 12.5 % higher than that of pure copper. The optimum thermal processing parameters were identified in the range of 782-950 degrees C and strain rates of 0.015-0.333 s(-1). Under this condition, finer grain microstructure and better overall properties can be obtained. OM and EBSD analyses showed that lowering the strain rate or increasing the thermal deformation temperature promoted dynamic recrystallization (DRX). In addition, changes in thermal deformation conditions affect the type, strength, and distribution of textures. The percentage of twinned region increases significantly with increasing thermal deformation temperature. TEM analysis at 800 degrees C and a strain rate of 0.01 s(-1) revealed alpha-Fe and Cr phases as the main precipitates, along with Cu-phase twinning along the [110] crystallographic zone axis. These findings provide deeper insights into the mechanisms driving property changes in Cu-0.8Fe-0.2Cr alloys with low Fe content under varying thermal processing conditions.
10.1016-j.jallcom.2025.180398	2	corrosion; surface; film; electrochemical; films; spectroscopy; layer; current; solution; potential; resistance; composition; x-ray; ions; showed	Cu-Ni alloy thick films with a thickness of approximately 170 mu m were electrodeposited from an aqueous solution containing pyrophosphate as a complexing agent. The electrodeposited Cu-Ni alloy thick films with a dumbbell shape were exfoliated from a metallic titanium cathode to examine the crystal orientation, microhardness and tensile strength . The average crystallite size of electrodeposited Cu-Ni alloy thick films was around 30 nm. The microhardness increased up to 327 HV with increasing the Ni content up to similar to 19 % while the maximum tensile strength reached 726 MPa at the Ni content of similar to 13 %. The improvement of these mechanical properties can be explained by two strengthening mechanisms of solid solution alloying and crystallite size refining.
10.1016-j.jallcom.2025.180399	14	strength; properties; conductivity; electrical; mechanical; cu-; grain; mpa; electrical conductivity; aging; precipitation; phase; mechanical properties; tensile; phases	This study explores the phase transformations and metastable states in a Cu-20 m.% Sn alloy, focusing on both stable and martensitic phases. High-energy X-ray diffraction (HEXRD) analyses revealed a metastable phase range between 200 degrees C and 375 degrees C. Identifying phases within this range was challenging due to the incomplete crystallographic descriptions of reported phases in the literature. Correlative transmission electron microscopy analysis identified three different phases, assigning alpha ' and R phases with certainty and tentatively designating a third phase as R1 ''. Further confirmation using HEXRD was inconclusive due to the limited available data on the structure of R1 ''. Atom probe tomography supported the presence of R1 '' by revealing distinct chemical regions, correlating the alpha ' and R1 '' phases, and indicating coupled growth as lamellar precipitates. Despite limited descriptions of R1 ', additional HEXRD investigations suggested its metastability. Martensitic transformation conditions were analyzed, showing that the alpha ' + R1 ' phases can be induced through aging, contrary to existing literature. Comparative diffractogram analysis, including a direct comparison of the metastable phases with the diffractogram of a cymbal-known for its exceptional acoustic properties-suggests that the alpha ' + R1 '' phases could similarly enhance acoustic performance, expanding the understanding and potential applications of Cu-Sn alloys.
10.1016-j.jallcom.2025.180405	8	hot; deformation; strain; strain rate; dynamic; hot deformation; recrystallization; dynamic recrystallization; flow; rate; flow stress; compression; constitutive; degrees; stress	Hot deformation behavior of Cu-9Ni-6Sn alloy has been investigated by isothermal compression tests in the temperature range of 750 degrees C to 900 degrees C and the strain rate range of 0.01 s-1 to 10 s-1. The flow stress constitutive equation of the Cu-9Ni-6Sn alloy was developed by hyperbolic sine function with the calculated activation energy of 246.177 kJ/mol, basing on the peak stress. Meanwhile, the Arrhenius-type constitutive model was used to predict the flow behavior of the alloy, yet the deviation between the experimental and predicted flow stress seem to be large. Whereas, using a two-stage physically based model, combining the Bergstrom and JMAK equations, well predicts the whole hot flow behaviors of the Cu-9Ni-6Sn alloy. The values of coefficient and average relative error by two-stage physically based model are 0.99863 and 1.3953 %, respectively. Microstructure evolution reveals that dynamic recrystallization process become inhomogeneous, further influencing the flow behavior and softening behavior of the Cu-9Ni-6Sn alloy. The initial microstructure, containing dendrite segregation and low angle grain boundaries concentrated between secondary dendrite arms, is the main reason make dynamic recrystallization process be inhomogeneous. Dynamic recrystallization behavior shows that continuous dynamic recrystallization and discontinuous dynamic recrystallization soften the alloy at the condition of low deformation temperature and high strain rate to dynamic grain growth soften the alloy at the condition of high deformation temperature and low strain rate. Moreover, when deformation at 850 degrees C, the mechanism of discontinuous dynamic recrystallization assisted transform from by twinning to by twinning and triple grain boundary nucleation synergy with strain rate decrease from 10 s-1-1 s-1 to 0.1 s-1-0.01 s-1.
10.1016-j.jallcom.2025.180437	6	grain; deformation; strain; strength; dislocation; cu-; tensile; size; ecap; grain size; sfe; ductility; hardening; high; stress	As a heterostructured (HS) material with excellent mechanical properties, gradient structure (GS) materials have been widely studied. The global constraint in GS materials has been reported: the tensile mechanical properties of samples with double-sided gradient layers are superior to single-sided ones. This discovery advances the study of complex stress states induced by the interaction between GS and coarse-grained (CG) layers. According to the theory of HS materials, the reduction of stacking fault energies (SFEs) will also allow the geometrically necessary dislocations (GNDs) on the GS/CG interface to be more optimal arrangement. Therefore, it is necessary to understand the potential connection between SFEs and global constraints. In this study, Cu-Zn alloys with different stacking fault energies and single/double-sided gradient layers were prepared by surface mechanical attrition treatment (SMAT). It is found that the lower SFE samples exhibit more significant global constraint phenomena. Preliminary research suggests that global constraints are attributed to the double-sided structure, which produces a more effective heterogeneous deformation induced (HDI) effect, while lower SFEs promote this effect. This study provides new insights into the design of gradient layers and stress-strain partitioning design for GS materials.
10.1016-j.jallcom.2025.180459	-1		Shape memory alloys are highly attractive for mechanical damping applications due to their special capacity of energy dissipation given by the hysteretic superelastic effect. In this study, we demonstrate a significant enhancement in damping capacity in Cu-Al-Mn shape memory alloys achieved by substituting Fe for Al. Our findings indicate that in the studied Cu70.5Al18-xMn11.5Fex (x = 0, 0.5, 1.0, and 1.5) alloys, the thermal hysteresis for the Fe-doped alloys (i.e., higher than 30 K) is enhanced by two times when compared to that of ternary alloy (i.e., similar to 9 K), leading to a substantial increase in stress hysteresis during the superelastic cycle. Consequently, very prominent dissipated energy (Delta W) of 11.19 +/- 0.09 MJ m(-3) is obtained in a directionally solidified Cu70.5Al17Mn11.5Fe1 alloy, giving rise to a high loss factor (eta) of up to 0.212 +/- 0.001. Moreover, the resulting merit index (E-1/2eta) of damping capacity, as high as 0.859 +/- 0.009, is substantially higher than those in other bulk damping materials.
10.1016-j.jallcom.2025.180562	-1		The (Cu-Ge)100-xAlx alloys with different contents of Ge and Al solutes were designed to investigate the influence of solute elements on the microstructural evolution and chromatic and mechanical properties of the alloys. The addition of 0 -9 at% Al solute to the Cu97Ge3, Cu95Ge5, and Cu93Ge7 alloys led to microstructural evolution from a single-phase (alpha-Cu) to dual-phase structure consisting of alpha-Cu matrix and bimodal-sized zeta-Cu17Ge3 phase. The alloys with small amounts of Ge and Al have a single-phase structure or dual-phase structure with nanoscale zeta-Cu17Ge3 precipitates. An increase in Ge and Al solute induces the formation of a microscale interdendritic zeta-Cu17Ge3 phase with the alpha-Cu matrix, and the nanoscale Cu17Ge3 precipitates during solidification. The chromaticity (CIE a* and b* values) of the alloys is significantly influenced by the solute content as well as the microscale zeta-Cu17Ge3 phase. However, nanoscale zeta-Cu17Ge3 precipitates are ineffective in changing chromaticity. For the mechanical properties of alloys, the nanoscale zeta-Cu17Ge3 precipitates and microscale zeta-Cu17Ge3 phase contribute to improving the Vickers hardness via precipitation hardening and dispersion hardening effects. These results provide an effective way to expand the chromatic color range and improve the mechanical properties by developing dual-phase Cu-based alloys with a bimodal-sized second phase.
10.1016-j.jallcom.2025.180700	14	strength; properties; conductivity; electrical; mechanical; cu-; grain; mpa; electrical conductivity; aging; precipitation; phase; mechanical properties; tensile; phases	This study investigates the microstructure, mechanical properties, and tribological behavior of Cu-Ag-Al alloy coatings with varying Ag/Al ratios. The coatings exhibit a dual-layer structure comprising a Cu-Ag-Al ternary surface layer and an Ag interlayer, where increasing Ag interlayer thickness (210-610 mu m) directly enhances the eutectic phase fraction (27-73 %). Phase evolution is composition-dependent: high-Al Cu-19Ag-20Al forms R' phases via R -> R' ordering, while lower-Al alloys (Cu-34Ag-15Al, Cu-45Ag-12Al) stabilize Cu solid solutions (Cu S. S.) with nanotwins due to suitable stacking fault energy (SFE). Mechanical performance is governed by dual-phase interactions: the R' phase in Cu-19Ag-20Al achieves high hardness (4.71 GPa) and work-hardening rates (2699 MPa) via coherent (128)-plane interfaces, whereas nanotwin-strengthened Cu S.S. phases dominate in low-Al alloys. Tribological analysis reveals that increasing Ag content reduces friction coefficients (0.72 -> 0.33) through the formation of Ag-rich nanocrystalline tribolayers. However, wear resistance peaks in Cu-34Ag-15Al (397 mu m scar width), balancing 42 vol% hard Cu S.S. phases with 58 vol% friction-reducing eutectic structures. Excessive eutectic content in Cu-45Ag-12Al compromises wear resistance despite low friction, underscoring the necessity of optimizing phase hardness and tribolayer efficacy. These findings highlight the critical role of Ag/Al ratio in tailoring phase selection, strengthening mechanisms, and wear performance in Cu-based coatings.
10.1016-j.jallcom.2025.180732	-1		High-pressure torsion (HPT) processing disrupts the thermodynamic equilibrium in immiscible systems and often produces nonequilibrium microstructures with unique properties. This study investigates the microstructural evolution and mechanical behaviour of a Cu-Nb immiscible alloy subjected to HPT under 6 GPa compressive stress. The HPT processing was performed on stacked Cu-Nb-Cu layers by up to 200 turns and this produced mechanically alloyed, homogenized disks free of porosity or cavities. Microstructural characterization using X-ray diffraction and scanning electron microscopy, coupled with energy-dispersive X-ray spectroscopy, revealed a stepwise evolution, including the reduction of segregation layers, the formation of nonequilibrium Cu-17 at%Nb solid solution in the disc processed at 200 HPT turns and an increased Nb insertion into the Cu lattice. Additionally, grain refinement and residual strain increments were observed with increasing torsional turns. Thereafter, the mechanical properties were evaluated using hardness mapping and tensile testing. The material exhibited strain hardening behaviour and achieved an ultimate tensile strength (UTS) exceeding 1.25 GPa. Following post-deformation annealing, the UTS decreased to similar to 700 MPa due to recrystallization and recovery. These results provide a preliminary understanding of microstructural transformations and their impact on the mechanical properties of immiscible systems subjected to extreme deformation.
10.1016-j.jallcom.2025.180774	14	strength; properties; conductivity; electrical; mechanical; cu-; grain; mpa; electrical conductivity; aging; precipitation; phase; mechanical properties; tensile; phases	This study utilized Sc doping to form a new intermetallic compound and was combined with SRA (Solution + 75 % Rolling + Aging) process to control the in-situ formation of the Cu-4(Sc, Zr) phase and its precipitation behavior at micro and nano scales, thereby enhanced the comprehensive properties of the alloy. Compared to the normal SA (Solution + Aging) process, the SRA (Solution + 75 % Rolling + Aging) process is more conducive to the simultaneous improvement of mechanical and electrical properties. When the Sc content is 0.15 %, under the SRA peak aging condition (400 degrees C x 4 h), the hardness, electrical conductivity, and strength were 196.45 +/- 2.16 HV, 72 % IACS, and 540.79 +/- 10.1 MPa, respectively. The alloy maintained high strength and hardness under small rolling reduction due to the fine dispersion of the Cu-4(Sc, Zr) phase at small sizes (similar to 5.27 mu m) at the micron scale (similar to 0.41 %) and nanoscale precipitation. The nanoscale Cu-4(Sc, Zr) phase forms based on substitution in the Cu4Sc crystal structure. After the SRA process, an orientation relationship of [110](Cu)//[012](Cu4(Sc, Zr)), ((1) over bar1 (1) over bar )Cu//(100)(Cu4(Sc, Zr)) between the Cu-4(Sc, Zr) phase and the matrix is established, and its size is significantly refined, with stacking faults observed internally. The orientation relationship of the Fcc-Cr phase changed from [(1) over bar 12](Cu)//[011](Cr), ((1) over bar1 (1) over bar)(Cu)//((2) over bar 00)(Cr) in the peak aging state of the SA process to a Cube-on-Cube. This indicates that deformation processes can alter the orientation relationships of precipitates, and the presence of metastable phases contributes to improving the comprehensive properties of the alloy.
10.1016-j.jallcom.2025.180835	14	strength; properties; conductivity; electrical; mechanical; cu-; grain; mpa; electrical conductivity; aging; precipitation; phase; mechanical properties; tensile; phases	During the preparation of Cu-Y2O3/W composites via the in-situ reaction method, the introduction of ammonium metatungstate (AMT) and WO3 as W precursors often leads to oxygen contamination, which degrades the mechanical and electrical properties of the copper matrix. To address this issue, the alloy Cu-Y-W-O composite powders were subjected to hydrogen reduction at 600 degrees C and 800 degrees C, followed by densification through spark plasma sintering (SPS). The results demonstrate that hydrogen reduction at 800 degrees C more effectively eliminates oxygen impurities and inhibits the formation of Y-W-O compounds, leading to a uniform dispersion of Y2O3 and W particles. The AMT sample achieved a tensile strength of 337 MPa and an elongation of 28 %, while the WO3 sample reached 365 MPa and 19 %. Both electrical conductivity and densification were significantly enhanced after reduction. This study underscores the importance of high-temperature hydrogen reduction as a key step in refining the microstructure and improving the overall performance of Cu-Y2O3/W composites.
10.1016-j.jallcom.2025.180869	-1		Grain-refined Cu-Al-Mn shape memory alloys (SMAs) were prepared by vacuum suction casting and adding Ce element. Microstructure, mechanical and damping properties of the alloys were investigated systematically. The experimental results showed that the Cu-Al-Mn SMA was gradually refined with decreasing in the inner diameter of casting mold, and it could be further refined after adding Ce. When its addition was 1.0 wt%, the average grain size of the alloy cast using the Phi 8 mold is decreased to similar to 15.8 mu m, the great refining effect is attributed to the rapid cooling rate during vacuum suction casting and the constraint of Al11Ce3 precipitation on grain growth . Besides, the rapid cooling speed was helpful to directly obtain the refined martensite in the cast alloy without the subsequent austenitizing and quenching. Moreover, this characteristic of short process in the vacuum suction casting could avoid secondary grain growth of the refined alloy during subsequent heat treatments. Properties tests showed that both the mechanical and damping properties of the alloys were significantly improved. The Cu-Al-Mn SMA with the best grain refining effect showed a good balance between the two properties, the yield strength, tensile strength and elongation reached 289 MPa, 810 MPa and 6.2 %, respectively, with the room-temperature damping increased to similar to 0.027 at the same time. The strengthening of the alloy was ascribed to the coordination of grain refinement, efficient load transfer, and the greatly decrease of casting defects. The enhancement of damping was mainly attributed to the increase of interface density, including grain boundaries, martensite interfaces, twin and phase interfaces.
10.1016-j.jallcom.2025.180959	14	strength; properties; conductivity; electrical; mechanical; cu-; grain; mpa; electrical conductivity; aging; precipitation; phase; mechanical properties; tensile; phases	This study develops FeCoCrNi high-entropy alloy (HEA) particle-reinforced copper matrix composites, leveraging the FCC structure of both HEA and Cu to enhance interfacial bonding, facilitate load transfer, and minimize lattice mismatch defects. The composites were synthesized via ball milling and spark plasma sintering (SPS), ensuring uniform HEA dispersion and refined microstructures. This work systematically evaluates the effects of HEA content on mechanical, thermal, electrical, and thermoelectric properties, providing insights into strengthductility synergy, thermal transport, and electronic conductivity. The findings advance HEA-based metal matrix composites for structural and functional applications.Specifically, the 20 wt% HEA/Cu composite achieved a yield strength of 164 MPa, and the 15 wt% HEA/Cu composite exhibited a tensile strength of 283 MPa. Maximum elongation of 30 % was observed with 10 wt% HEA, though both strength and elongation decreased with higher HEA content. Instrumented indentation revealed a gradient in hardness and elastic modulus between the reinforcement and the matrix. The 15 wt% HEA/Cu composite retained 60 % of the thermal conductivity of pure copper (223 W/m & sdot;K at room temperature), and the 10 wt% HEA/Cu composite maintained 60 % electrical conductivity of copper (23.3 MS/m). Although the thermoelectric figure of merit (ZT) was initially low, it improved with temperature.
10.1016-j.jallcom.2025.181024	-1		The trade-off between strength and ductility is usually existing in Cu alloys. Recently, it has been reported that designing heterogeneous structure in metallic materials can alleviate the paradox between strength and ductility. In this study, heterogenous gradient structure is formed via rotary swaging (RS) and subsequent annealing. The results demonstrate that after the RS treatment, the grain size from the edge to the center is significantly refined with a gradient distribution, and the yield strength is as high as 730.6 MPa, but the ductility is only 2.3 %. After annealing, the RS-320-20 sample (RS sample annealed at 320 degrees C for 20 min) consists of refined deformation grains and recrystallized grains. In addition, the recrystallized grains are surrounded by the deformed grains, and the grain size distribution still maintains a gradient distribution. The RS-320-20 sample exhibits a high yield strength of 575.2 MPa and high ductility of 16.5 %. Moreover, TEM microstructure reveals that dislocations are accumulated near the recrystallized grains at the interface between the deformed and recrystallized grains, which indicates that an obvious HDI strengthening is produced at the heterogenous interface. With the increasing strain to 10 %, deformation twins are activated near the recrystallized grains, resulting in high strain hardening capability. Therefore, the high strength originates from refined grains and heterogeneous deformation-induced (HDI) strengthening. The excellent ductility results from recrystallized grains, significant HDI hardening and activation of deformation twins. These findings offer insights into tuning the heterogenous gradient structure distribution to obtain superior combination of strength and ductility of Cu alloys.
10.1016-j.jallcom.2025.181025	-1		The pursuit of endowing copper alloys with outstanding mechanical properties and favorable workability has long presented a formidable challenge. In this paper, Mg was added to Cu-0.6Cr alloy to improve its hot working properties. We used the Gleeble-1500 thermal simulator system to investigate the hot deformation behavior and microstructure evolution of Cu-0.6Cr alloy and Cu-0.6Cr-0.2Mg alloy at 750-950 degrees C under different strain rates. Under the same experimental conditions, the addition of Mg increased the flow stress of Cu-0.6Cr alloy. By establishing the constitutive equations of both alloys, it was found that the activation energy of the alloys increased from 276.8 kJ/mol to 321.3 kJ/mol with the addition of Mg, which enabled the alloys to better resist localized deformation and fracture, and thus improved the formability of the alloys. Based on the microstructure, it can be observed that after hot deformation, the grain size and the percentage of recrystallized grains in the Cu0.6Cr-0.2Mg alloy are smaller than those of the Cu-0.6Cr alloy. This is due to the fact that the addition of Mg causes the formation of CuMg2 phase in the alloy during the hot deformation, which hinders the movement of dislocations and the migration of grain boundaries, and inhibits the growth of grains during the dynamic recrystallization process.
10.1016-j.jallcom.2025.181089	15	aging; strength; conductivity; electrical conductivity; electrical; mpa; treatment; strengthening; degrees; cu-; cold; precipitation; tensile strength; tensile; iacs	The microstructural evolution of the Cu-3Ti-0.5Mg-0.5Sn alloy after the first and secondary cold rolling combined with aging treatments was investigated using scanning electron microscopy (SEM) and transmission electron microscopy (TEM). In addition, the mechanical properties and electrical conductivity of the designed alloy were tested after different aging times to determine the performance variations of the alloy during the twostep thermomechanical treatment. The results show that after the second cold rolling and aging treatment (Process II), the conductivity and tensile strength of the Cu-3Ti-0.5Mg-0.5Sn alloy were both effectively improved compared with those after the first cold rolling and aging treatment (Process I). The optimum process was determined to be 60 % cold rolling-*aging at 380 degrees C for 6000 min -*60 % cold rolling, followed by aging at 350 degrees C for 6000 min, resulting in a tensile strength of 1100 MPa and an electrical conductivity of 25.7 %IACS. Ti3Sn intermetallic compounds were formed, which reduced the Ti and Sn contents dissolved in the Cu matrix, thus enhancing the electrical conductivity of the alloy. Long-term, low-temperature aging promoted the formation of nanoscale alpha-Cu4Ti precipitates and maintained the multiplication of dislocations.
10.1016-j.jallcom.2025.181243	14	strength; properties; conductivity; electrical; mechanical; cu-; grain; mpa; electrical conductivity; aging; precipitation; phase; mechanical properties; tensile; phases	Cu-Cr-Nb is a high-strength, high-conductivity copper alloy that outperforms most copper alloys, particularly at high temperatures. Due to limited powder acquisition channels, most additive manufacturing research on Cu-Cr-Nb alloys focuses on systems with a Cr/Nb ratio of 2:1, particular on Cu-4Cr-2Nb (at%). However, there are few studies on the microstructure and properties of Cu-Cr-Nb alloys with different Cr/Nb ratios prepared by additive manufacturing. This study utilizes ball-milled elemental powders of Cu, Cr, and Nb as raw materials for laser directed energy deposition (L-DED) to fabricate five different Cu-Cr-Nb alloys, maintaining a total alloy content of approximately 6 at%. At the micron and submicron scales, Nb-rich alloys consisted primarily of Nb particles and Cr2Nb, while Cr-rich alloys mainly comprised Cr particles and Cr2Nb. Notably, nano-scaled Cr precipitates and dense dislocations were observed in all as-built alloys. Alloys with different Cr/Nb ratios did not exhibit significant differences in mechanical and electrical properties in the as-built state. During the direct aging process, the residual supersaturated solution continued to decompose and coarsen the Cr precipitates formed during intrinsic heat treatment. As a result, hardness remained largely unchanged, while electrical conductivity increased to above 70 % IACS. The hardness of Cu-1Cr-5Nb, Cu-2Cr-4Nb, and Cu-3Cr-3Nb showed only slight changes, while both the hardness and conductivity of Cu-4Cr-2Nb and Cu-5Cr-1Nb alloys were notably enhanced after aging at 400 degrees C for 24 hours followed by solid solution treatment. Specifically, a hardness of 117.4 HV and a conductivity of 86 % IACS were obtained in Cu-4Cr-2Nb, while 124.8 HV and 84 % IACS were achieved in Cu-5Cr-1Nb. This work provides valuable insights into the microstructure and properties of Cu-Cr-Nb alloys with varying Cr/Nb ratios, fabricated using L-DED with elemental powder mixtures. The findings also offer practical guidance for optimizing composition and heat treatment in the production of Cu-Cr-Nb alloys.
10.1016-j.jallcom.2025.181249	14	strength; properties; conductivity; electrical; mechanical; cu-; grain; mpa; electrical conductivity; aging; precipitation; phase; mechanical properties; tensile; phases	Copper alloys are promising candidates for future fusion reactor heat sink materials due to their exceptional thermal conductivity and strength . However, improving strength while maintaining high thermal conductivity remains a key challenge. To address this issue, nanoparticle-reinforced Cu-5W and Cu-5W-0.5HfC alloys were fabricated by ball milling and fast hot pressing (FHP), and their microstructure and properties were subsequently analyzed. The results indicate that the yield strength of the Cu-5W-0.5HfC alloy increases by 65 %, reaching 256 MPa, compared to Cu-5W, while maintaining a similar elongation (similar to 18 %). Both Cu-5W and Cu-5W-0.5HfC exhibit electrical conductivities greater than 91 %, and their thermal conductivities at room temperature exceed 340 Wm(-)(1)K(-)(1) . The nano HfC particles can purify the grain boundaries, further refine the grains, and significantly enhance the alloy's strength . This study demonstrates the potential of nano-HfC reinforced Cu-W alloys to synergistically improve strength, ductility, and thermal conductivity for advanced applications.
10.1016-j.jallcom.2025.181253	1	shape; memory; shape memory; damping; martensite; martensitic; damping capacity; transformation; capacity; strain; superelasticity; temperature; cu-al-mn; shape memory effect; effect	Precipitation of ductile alpha phase can generally improve the ductility of Cu-based shape memory alloys but impair their shape memory effect (SME). An abnormal positive dependence on amount of the alpha phase was reported in both conventional Cu-Zn-Al and ductile Cu-Al-Mn alloys. To clarify reason for this abnormal dependence, we systematically investigated relationship between the martensitic transformation behavior and the amount of alpha phase in a ductile Cu-17.5Al-9.4Mn alloy. The results revealed that the occurrence of martensitic stabilization due to slow heating could rationalize the abnormal dependence. The reduced amount of stabilized martensites was proportional to the amount of alpha phase. An inverse dependence of SME on the Ms temperature existed in the ductile Cu-Al-Mn alloys, regardless of the intrusion of alpha phase.
10.1016-j.jallcom.2025.181299	14	strength; properties; conductivity; electrical; mechanical; cu-; grain; mpa; electrical conductivity; aging; precipitation; phase; mechanical properties; tensile; phases	The longstanding trade-off between mechanical strength and electrical conductivity has limited the practical application of Cu-Ti alloys. In this study, a single-pass hot-rolling step introduced prior to solution-aging effectively enhanced both properties in a Cu-3.2 wt% Ti alloy. The treated alloy exhibited a hardness of 258.6 HV, a yield strength of 678.2 MPa, a tensile strength of 970.5 MPa, an elongation of 15.5 %, and an electrical conductivity of 23.12 % IACS. We attribute these improvements to precipitation of a metastable, coherent, ordered alpha-Cu4Ti phase with a body-centered tetragonal (BCT) crystal structure. In contrast to solutionaged or multi-pass hot-rolled alloys, our single-pass process generates an exceptionally high density of dislocations. Following solution treatment, the dislocation network refines and becomes uniformly distributed. During aging, the alpha-Cu4Ti phase preferentially nucleates at these refined dislocations, reducing matrix supersaturation and yielding a uniform dispersion of nanoscale precipitates. The resulting fine alpha-Cu4Ti precipitates markedly enhance both the electrical conductivity and mechanical strength of the alloy.
10.1016-j.jallcom.2025.181345	14	strength; properties; conductivity; electrical; mechanical; cu-; grain; mpa; electrical conductivity; aging; precipitation; phase; mechanical properties; tensile; phases	In this study, Copper-Cobalt-based granulated and non-granulated powders were investigated using FieldAssisted Sintering Technology (FAST) and conventional sintering. Phase composition analysis via Rietveld refinement of X-Ray Diffraction data demonstrated that the sintering method critically influenced the microstructural evolution. Conventional sintering of one of the investigated compositions (BOND1H) led to the formation of the FeCo intermetallic due to a prolonged exposure to high temperatures. On the other hand, FAST processing preserved discrete iron and cobalt phases. The FAST process exhibited superior efficacy for nongranulated powders, achieving 91.4 % theoretical density in one of the samples (BOND2R) with minimal defects, compared to granulated systems where binder decomposition induced porosity. Remarkably, FASTprocessed BOND2R composition attained hardness values (245 +/- 32 HRB) equivalent to the conventional counterparts (240 +/- 10 HRB) despite differences in densification. These results underscore the dual influence of sintering strategy and powder morphology on microstructural control, defect formation, and mechanical performance in Copper-Cobalt-based systems.
10.1016-j.jallcom.2025.181415	14	strength; properties; conductivity; electrical; mechanical; cu-; grain; mpa; electrical conductivity; aging; precipitation; phase; mechanical properties; tensile; phases	This study examined the impact of the Al/Sc atomic ratio on the electrical conductivity, mechanical properties, and thermal stability of pure copper. By regulating the Al/Sc atomic ratio within the range of 1-3, the microstructure of the alloy was characterized via OM, EBSD, and TEM, among other methods. The results demonstrated that when the Al/Sc atomic ratio was approximately 3, the overall performance of the alloy was the most favorable. After a series of processing treatments, the conductivity, hardness and tensile strength in the coldrolled state are 87.2 % IACS, 145 HV and 396 MPa respectively, and the softening temperature is approximately 510 degrees C. After being treated at 850 degrees C for 30 min, the conductivity increases to 95.6 % IACS, the hardness decreases to 57.4 HV, and the average grain size is 72.92 mu m. When the atomic ratio of Al/Sc is approximately 3:1, under high-temperature conditions, Sc atoms almost entirely take part in the formation of oxide precipitation phases (such as Al2O3 and AlScO3), preventing the formation of excessive Sc solid solution or coarse phases (such as AlSc2). Furthermore, a large quantity of spherical Al2O3 precipitated phases with a size of approximately 6.9 nm, which are dispersed within the grain boundaries, have been formed. These small-sized particles offer a high density of pinning points. Simultaneously, ellipsoidal AlScO3 precipitated phases with a size of approximately 18 nm have been formed on the grain boundaries,The larger particles can effectively stabilize the grain boundaries and inhibit their migration rate under high temperatures, thereby significantly improving the strength and thermal stability of the alloy.
10.1016-j.jallcom.2025.181604	-1		High-quality oxide films on 70/30 copper-nickel alloys are crucial for reducing the risk of material failure. In this study, a 0.1 T magnetic field was employed to strengthen the oxide films grown in a 3.5 % NaCl solution, aiming to improve its protective performance and extend the service life of the alloys. The protective properties of the oxide films were evaluated using potentiodynamic polarization curves and electrochemical impedance spectroscopy, while its composition and structure were analyzed by Raman spectroscopy, X-ray photoelectron spectroscopy, and transmission electron microscope. The results demonstrate that the oxide films grown under a 0.1 T magnetic field exhibits superior corrosion resistance compared to those formed under non-magnetic field, with an impedance value increased by at least 100 %. Furthermore, the surface roughness of the films was reduced, the thickness was increased, and the ratio of NiO/Ni(OH)2 in the inner layer of the film was significantly enhanced, which also reduced the driving force for film dissolution. These improvements are attributed to the synergistic coupling effects of Lorentz force and gradient magnetic force. This study provides a novel strategy for enhancing the surface oxide films of 70/30 copper-nickel alloys.
10.1016-j.jallcom.2025.181746	-1		In this paper, high-speed laser cladding and high-speed laser remelting were used to prepare W/Cu alloy coatings on the surface of Cu alloys. The effects of two processes on the diffusion of W/Cu elements are examined from the perspectives of phase composition, microstructure, and thermal stress, and finally, the influence of element diffusion on coating quality is validated through mechanical properties, including hardness and wear behavior. The results show that the coating quality after the remelting process is higher, the microstructure evolved from slender secondary dendrites to short secondary dendrites to snowflake crystals, the maximum diffusion distance of W/Cu element increases from 1.53 mu m to 1.79 mu m, the hardness increases from 181.7 HV0.2 to 213.5 HV0.2, and the COF is also reduced by 23.1 %. This study provides a technical reserve for the preparation of W/Cu alloy coatings with significantly improved comprehensive properties, and provides a necessary theoretical basis for the diffusion behavior between alloying elements in immiscible systems.
10.1016-j.jallcom.2025.181815	-1		Cu-Ta composites exhibit superior overall performance and application potential, but research and fabrication related to conductors remain limited. In current work, Cu100-xTax (x = 10, 15, 20, 25 wt%) composites were fabricated through the combination of powder metallurgy, followed by rotary swaging and drawing at relatively low strain. The effects of Ta content on the microstructure evolution, mechanical and electrical properties were investigated. The microstructure of Cu-Ta composite with elongated Cu grain exhibited enhanced Ta particle dispersion during plastic deformation stages. The deformation texture of the Cu matrix can be found along with longitudinal section. The average size of partial Ta nanoparticles reduces to 24.8 nm in the approximate center region. The increasing of Ta content could promote Cu grain refinement and improve mechanical strength, but reduce plasticity of Cu-Ta composites. With increasing Ta content from 10 to 25 wt%, the ultimate tensile strength, Vickers hardness, and compressive yield strength reach ranges of 379-498 MPa, 123.7-159.4 HV, and 315-411 MPa, respectively. Despite the slight decrease of electrical conductivity caused by existence of Ta phase, the conductivity of all composites exceeded 68 % IACS. The results could provide valuable insights for fabricating Cu-based composites aiming to the wire form application.
10.1016-j.jallcom.2025.181831	14	strength; properties; conductivity; electrical; mechanical; cu-; grain; mpa; electrical conductivity; aging; precipitation; phase; mechanical properties; tensile; phases	Cu-Al-Si porous materials are synthesized through a thermal explosion (TE) route, and the influence of Al-Si powder on the structure and properties is systematically investigated. The Al-Si powder is ball milled, which reduces the average grain size and increases specific surface area. These changes lead to heat accumulation and exothermic release during the reaction, leading to denser microstructures and improved integrated performance. The Cu-Al-Si samples exhibit a compressive strength of 55.72 MPa, significantly higher than that of the Cu-(Al/ Si) samples (30.45 MPa), along with distinct fracture modes under compression. After oxidation at 800 degrees C for 288 h, the Cu-Al-Si samples show a minimal mass gain (3.60 %), resulting from the formation of a continuous protective Al2O3 film. In 0.5 mol/L H2SO4, the Cu-Al-Si samples exhibit a more negative corrosion potential (-0.36 V) and a lower corrosion current density (0.38 mA/cm2) compared to Cu-(Al/Si), indicating reduced thermodynamic corrosion tendency and retarded corrosion kinetics with enhanced corrosion resistance. These results highlight the critical role of powder design in tailoring the microstructure and multifunctional performance of Cu-Al-Si porous materials.
10.1016-j.jallcom.2025.181880	-1		A novel heterogeneous microstructure in Cu-1Cr-0.1Zr alloy is successfully fabricated by solid solution (SS) treatment, aging treatment (AT), equal-channel angular pressing (ECAP) and annealing treatment. The heterogeneous microstructure was composed of grains and phases with multi-scale distributions, which exhibits a tensile strength of 647 MPa, elongation to failure of 15.9 % and electrical conductivity of 72.6 % IACS. The heterogeneous microstructure triggers a significant Bauschinger effect and hetero-deformation induced (HDI) stress, balancing the strength and ductility through cooperative deformation of hard and soft phases. Furthermore, the heterogeneous microstructure significantly improves electrical conductivity by optimizing grain boundary configurations and reducing lattice defect density, thereby reducing electron scattering. This work provides new insights for designing heterogeneous microstructure of copper alloys with high comprehensive performance.
10.1016-j.jallcom.2025.181902	-1		Cu-W alloy has been widely applied of is due to the combination of the high melting point and high strength of W metal and the good electrical conductivity of Cu metal. In this study, the first-principles were used to construct Cu-Cr-W alloy models with different Cr ratios, and their electronic structures and elastic constants were calculated. The results show that the introduction of Cr atoms changes the energy of the electron states of Cu-3d and W-5d orbitals, promoting them to couple and form bonds more easily. Moreover, Cr-3d and W-5d orbitals can form strong bonds, resulting in an increase in the bulk modulus, Young's modulus and shear modulus of the material with the increase in the number of Cr atoms. According to this calculation trend, Cu-W alloys with different Cr contents were prepared by mechanical alloying according to the atomic ratio and sintered into billets by SPS to study their structures and properties. Experiments show that when the Cr addition reaches 4 at%, the material has the best strength and hardness. The tensile yield strength is increased by about 34.7 % compared with that of the Cu-W alloy, and the tensile strength is increased by about 30.4 %. Considering the combination of material strength and electrical conductivity, when the Cr addition is 1-2 at%, the material has both excellent electrical conductivity and tensile strength . In addition, an appropriate amount of Cr can refine the grains. The diffusion of Cr on the surface of W particles to form Cr0.5W0.5 and its own hard characteristics are the main reasons for improving the tensile strength of Cu-Cr-W. By comparing the calculated elastic constants and the experimentally obtained changes in mechanical properties, it is found that the trend of the calculation results can well match the experimental results.
10.1016-j.jallcom.2025.182049	14	strength; properties; conductivity; electrical; mechanical; cu-; grain; mpa; electrical conductivity; aging; precipitation; phase; mechanical properties; tensile; phases	Porous copper (3D Cu) materials have garnered significant attention in engineering fields such as catalysis, sensing, and flexible electronics due to their distinctive surface characteristics and exceptional mechanical properties. Nevertheless, conventional fabrication methods are substantially constrained by either intricate processing procedures or concomitant environmental pollution, which critically impedes their industrial-scale implementation. As an emerging alternative, vapor-phase dealloying (VPD) demonstrates remarkable industrialization potential owing to its streamlined process flow and enhanced equipment compatibility. It is noteworthy that current research predominantly focuses on bulk materials, leaving a pronounced technological gap in fabricating metallic foils within the 20-100 mu m thickness range. This study introduces an innovative stepwise pressure-modulated annealing protocol, through which controlled VPD treatment of brass foils successfully yields copper foils featuring three-dimensional interconnected pore channels. The breakthrough not only achieves precision engineering of ultrathin 3D Cu foils but also establishes a process-structure correlation model, providing both theoretical foundations and technical paradigms for developing eco-efficient nanoscale porous metallic foil manufacturing technologies.
10.1016-j.jallcom.2025.182098	-1		Cu-Al alloys have important applications as heat dissipation materials in automobiles. However, the heat dissipation and high-temperature resistance of Cu-Al alloys still need further improvement. In this study, Cucoated graphite, Ti2AlC, and Cu powder were used as raw materials, and a powder metallurgy process was employed to prepare Cu-Al alloys matrix composites synergistically reinforced by TiC and graphite. The results showed that during sintering, Ti2AlC and Cu undergo mutual diffusion, causing the Cu phase to transform into a Cu-Al alloys. Ti2AlC decomposes into TiC nanoparticles, releasing Ti atoms that promote the formation of a TiC interfacial transition layer between graphite and the Cu-Al alloys. Additionally, after Ti2AlC decomposition, the corresponding region transforms into a composite structure of TiC nanoparticles and Cu-Al alloys. The composites show good density in their microstructure.
10.1016-j.jallcom.2025.182519	-1		The Nb3Sn/Cu superconducting wire, which is mainly prepared by bronze method, is the main material for large scientific facilities such as nuclear fusion reactors. However, the severe drawing fracture caused by poor plasticity of Cu-Sn alloy with high Sn content hinders the preparation of kilometer-level Nb3Sn/Cu superconducting wire with excellent properties. In the study, a novel method, named powder bronze method (PBM), that replacing buck Cu-Sn-Ti alloy with Cu-Sn-Ti alloy powder, was firstly proposed. The microstructure evolution of Cu-Sn-Ti alloy powder/Nb composite billet was discussed, and the formation mechanisms of Nb3Sn superconducting phase were systematically explored. The drawing experiment results reveal that the plasticity of Cu-Sn-Ti alloy is significantly improved by taking advantage of powder fluidity. The Cu-Sn-Ti alloy powder undergoes rearrangement, relative sliding, and plastic deformation, ultimately achieving densification, and the Nb grains are elongated along drawing direction. During the reaction heat treatment, the powder sintering densification and Nb3Sn generation occur synchronously. The Sn elements are gradually diffused from the interior of alloy powder to the powder boundary, which leads to the generation of sintering necks between powder particles. Meanwhile, the Sn atoms at the powder boundary are gradually diffused along the powder boundary to the Cu-Sn-Ti/Nb interface and react with Nb, which results in the generation of the Nb3Sn superconducting phase. It is worth noting that the Ti atoms diffuses from the interior of grains to the Cu-Sn-Ti /Nb interface along grain boundary and powder boundary, and the Ti-Sn intermetallic compound particles were observed at the Cu-Sn-Ti /Nb3Sn interface.
10.1016-j.jallcom.2025.182615	14	strength; properties; conductivity; electrical; mechanical; cu-; grain; mpa; electrical conductivity; aging; precipitation; phase; mechanical properties; tensile; phases	Precipitation-strengthened Cu-Ni-Co-P alloys are a promising new generation of high-strength and high-conductivity copper alloy for electronic applications. The mechanical and electrical properties of Cu-Ni-Co-P alloys are closely related to the precipitation behavior. This study comparatively analyzes the influence of Mg/Fe microalloying elements on the microstructure and properties of the Cu-Ni-Co-P based alloys by preparing Cu-0.3Ni-0.3Co-0.16 P, CuNiCoP-0.1Mg, and CuNiCoP-0.1Fe alloys. The evolution mechanisms of nano-precipitates in these alloys were investigated using transmission electron microscopy (TEM) and precipitation kinetics. The results show that the annealed CuNiCoP-0.1Mg, CuNiCoP-0.1Fe, and Cu-0.3Ni-0.3Co-0.16 P alloys after aging and cold rolling exhibited tensile strength of 698 MPa, 632 MPa, and 648 MPa, and electrical conductivity of 64 %IACS, 67.5 %IACS, and 63.8 %IACS. Compared to the Cu-0.3Ni-0.3Co-0.16 P alloys, the CuNiCoP-0.1Mg alloy show a 50 MPa strength increase with negligible electrical conductivity loss. The strength enhancement is primarily attributed to Mg microalloying, which suppressed the coarsening of the CoNiP precipitates, thereby enhancing precipitation-hardening effect. Conversely, the CuNiCoP-0.1Fe alloy exhibits a 16 MPa strength reduction but a 3.7 %IACS improvement in electrical conductivity. The addition of Fe element replaced partial Co/Ni atoms in the CoNiP phase, forming the (Ni, Co, Fe)2P precipitates. This increases the precipitate volume fraction and reduces the solubility of P element in the matrix, thereby enhancing electrical conductivity. This work provides valuable insights for designing high-performance Cu-based alloys via targeted microalloying strategies.
10.1016-j.jallcom.2025.182653	14	strength; properties; conductivity; electrical; mechanical; cu-; grain; mpa; electrical conductivity; aging; precipitation; phase; mechanical properties; tensile; phases	The discovery of double-peak hardening in Cu alloys provides new avenues for designing rapidly hardening precipitation strengthening Cu alloys. In this study, the effect of Fe and Ti solute concentrations on the doublepeak hardening behavior of Cu-Fe-Ti alloys corresponding to the first peak was systematically investigated. The results indicate that as the solute concentration increases, the aging time required to reach the first peak initially increases and then declines, while the corresponding peak hardness progressively increases, and the electrical conductivity gradually decreases. The precipitates formed at the first peak in all alloys consist primarily of GPzone-like coherent precipitates and FexTi phases, with the former being predominant. Additionally, the volume fraction of coherent precipitates formed at the first peak increases while their average size decreases with an increase in solute concentration. Specifically, the first peak of Cu-0.96Fe-0.48Ti appears after aging at 500 degrees C for 0.5 h, exhibiting a UTS of 543.5 MPa, an electrical conductivity of 64.9 % IACS, and an elongation of 15.9 %, and coherency strain strengthening serves as the dominant strengthening mechanism.
10.1016-j.jallcom.2025.182682	-1		The mechanical behavior of face-centered cubic (FCC) metals is significantly affected when limited grains are present in the cross section of specimen. We fixed the thickness of sheets, and studied the effect of grain size on the ductility of Cu-Al alloys with different stacking fault energies (SFEs). The ductility scales with grain size, but it starts to drop when the grain size is larger than a critical value (dc). Notably, two groups of critical grain size dc were revealed, which show close correlation with SFE. High dc (24.9-28.4 mu m) is observed in low-SFE Cu-Al alloys (gamma <= 15.8 mJ/m2), where deformation twinning is activated during tensile tests. In contrast, low dc (11.2-11.9 mu m) is found in medium-to-high SFE Cu-Al alloys (gamma >= 22.5 mJ/m2), which exhibit dislocation slip. The deformation twinning introduces barriers to dislocation slip and dynamically refines the original grain size, which leads to a larger dc and delays the appearance of specimen size effect in low-SFE alloys. This work bridges the size effect and SFE, and provides an accessible way to ameliorate the strength-ductility balance of miniature specimens through the twinning mechanism.
10.1016-j.jallcom.2025.182688	14	strength; properties; conductivity; electrical; mechanical; cu-; grain; mpa; electrical conductivity; aging; precipitation; phase; mechanical properties; tensile; phases	The stress relaxation behavior of the Cu-1.5Ni-1.1Co-0.6Si alloy and the corresponding microstructural evolution are investigated herein. Results indicate that dislocation recovery, preferentially occurring in grains with high internal strain, is the primary mechanism responsible for stress relaxation. Thermally activated atomic mobility at elevated temperatures facilitates dislocation movement and leads to an increased stress relaxation rate. During stress relaxation, the growth of nanoscale (Co, Ni)2Si precipitates is significantly limited, maintaining their effective resistance to dislocation motion and hindering the relaxation process. First-principles calculations show that Co atoms replace Ni sites in the Ni2Si phase to form (Co, Ni)2Si precipitates. This atomic substitution lowers the Gibbs free energy of the precipitates and enhances the interfacial adhesion energy between them and the Cu matrix, effectively inhibiting precipitate coarsening.
10.1016-j.jallcom.2025.182802	14	strength; properties; conductivity; electrical; mechanical; cu-; grain; mpa; electrical conductivity; aging; precipitation; phase; mechanical properties; tensile; phases	The influence of cold rolling and heat treatment on the microstructure and mechanical/electrical properties of Cu-15Ni-8Sn-0.4Nb-xV (x = 0.5, 0.7 wt%) alloys were systematically investigated. By incorporating a multi-component alloying design (Nb and V) combined with process optimization, effective control over microstructure, suppression of Sn segregation, inhibition of discontinuous precipitation (DP) phase formation, and an overall enhancement of properties in the Cu-15Ni-8Sn system were achieved. The Cu-15Ni-8Sn-0.4Nb-0.7 V alloy processed via thermo-mechanical treatment (cold rolling, pre-annealing, and aging at 400 degrees C for 12 h) exhibited exceptional comprehensive properties: a hardness of 408 HV, an ultimate tensile strength of 1170 MPa, an elongation of 9.71 %, and an electrical conductivity of 10.1 % IACS. This outstanding strength-ductility combination substantially surpasses that of most reported vacuum induction-melted Cu-15Ni-8Sn alloys, demonstrating the efficacy of the proposed alloying approach and processing route approachfor microstructural refinement and enhanced mechanical properties.
10.1016-j.jallcom.2025.182838	14	strength; properties; conductivity; electrical; mechanical; cu-; grain; mpa; electrical conductivity; aging; precipitation; phase; mechanical properties; tensile; phases	The microstructural evolution of Cu-4Ti and Cu-4Ti-0.2Sc alloys during aging at 450 degrees C and the effect of Sc addition on precipitation behavior and strengthening mechanism of the alloys were investigated. Cold-rolled Cu-Ti alloys have a high yield strength of 784 MPa owing to their high dislocation density. Adding Sc to Cu-Ti alloys at a rolling strain of 0.6 induces a higher dislocation density in the resulting alloys, generating a stronger dislocation-strengthening effect. As the Cu-Ti alloy ages, it undergoes spinodal decomposition and (3 ' and (3 phases precipitation. Spinodal decomposition is the predominant phase separation mechanism during initial aging (10-30 min), generating a strong spinodal-strengthening effect. Cu-Ti and Cu-Ti-Sc alloys have high strength (>950 MPa) after peak-aging, mainly because of dislocation- and spinodal-strengthening effects, contributing more than 70 % to the total strength of the peak-aged samples. Sc addition effectively promotes Ti aggregation in the Ti-rich region of the spinodal microstructure and increases the amplitude of compositional fluctuations of spinodal decomposition in the Cu-Ti alloy. Compared with the peak-aged Cu-Ti alloy, the peakaged Cu-Ti-Sc alloy has higher strength because of stronger spinodal- and dislocation-strengthening effects. On over-aging, (3 ' precipitates in the Ti-rich region, while (3 forms at the grain boundaries and slip traces. Further, the dislocation density decreases, weakening the dislocation-strengthening effect and gradually reducing alloy strength and hardness with prolonged aging. Moreover, Sc addition inhibits (3 precipitation in the Cu-Ti-Sc alloy.
10.1016-j.jallcom.2025.182923	14	strength; properties; conductivity; electrical; mechanical; cu-; grain; mpa; electrical conductivity; aging; precipitation; phase; mechanical properties; tensile; phases	The Cu-Ag alloy system serves as a cornerstone material for low-voltage electrical contacts due to its exceptional functional properties. Elevated silver costs have shifted research focus toward reducing Ag content while developing multifunctional composites. An innovative processing route was established to fabricate 3D graphene-reinforced Cu-0.12 wt% Ag composites, targeting enduring challenges in tribological behavior and service longevity for electrical contacts. Microstructural optimization was achieved through an integrated processing strategy comprising: in-situ graphene growth, low-energy ball milling, and rapid hot-pressing. This approach ensured homogeneous graphene dispersion and stable interfacial adhesion. The composite demonstrated substantially enhanced mechanical properties versus conventional CuAg alloys: 57 % higher yield strength (374 MPa), 11 % greater ultimate tensile strength (425 MPa), and 62 % increased fracture elongation. These improvements were achieved while maintaining competitive conductivity (similar to 95.5 % IACS). Crucially, the 3D interconnected graphene framework conferred exceptional wear resistance, reducing specific wear rate by 79.5 % and coefficient of friction by 50 % via interfacial lubrication and load-transfer effects. The composite exhibited a threefold enhancement in electrical contact durability (332 cycles) compared to commercial CuAg, attributable to exceptional graphene-reinforced thermal/arc-erosion stability. These findings demonstrate its potential as breakthrough material for next-generation electrical infrastructure.
10.1016-j.jallcom.2025.182937	14	strength; properties; conductivity; electrical; mechanical; cu-; grain; mpa; electrical conductivity; aging; precipitation; phase; mechanical properties; tensile; phases	Cu-12.5Ni-5Sn-xAl (x = 0, 0.5, 1.0, 1.5, 2.0, 2.5 wt%) alloys were fabricated using spark plasma sintering (SPS) technology. The effects of Al addition on the microstructure and mechanical properties were investigated. The results show that the addition of Al significantly refines the grain structure and promotes the precipitation of numerous nanosized γ′-Ni3Al particles within the grains. The dense dispersion of these Ni3Al phases in the CuNi-Sn-Al alloy enables a sustainable self-hardening deformation mechanism by acting as both dislocation sources and obstacles, thereby enhancing the strength and ductility of the material. This precipitation behavior effectively inhibits the nucleation of discontinuous precipitation (DP) and reduces its growth rate. With the addition of 2.0 wt% Al, both hardness and yield strength reach their peak aging values, at 374.2 HB and 908.1 MPa, respectively, which represent increases of approximately 50.6 % and 110.3 % compared to the alloy without Al. Molecular dynamics simulations further reveal that the yield strength of the model constructed based on the point-scan composition of intragranular particulate precipitates in Cu-12.5Ni-5Sn-2.0Al is significantly higher than that of the model established using the nominal composition of the Cu-12.5Ni-5Sn alloy.
10.1016-j.jallcom.2025.183013	-1		Studying the impact of doping elements, which cause segregation at grain boundary (GBs) due to low solubility, is crucial for understanding the mechanism of plastic deformation. This study reveals the plastic deformation mechanisms of Cu-Cr-Zr-Sc alloys during tensile testing based on in-situ EBSD observations. During deformation, random orientation changes occur within the grains. The input and output slip systems on both sides of the twin boundary are symmetrical along the twin boundary. Additionally, simultaneous activation of multiple slip systems and interactions between dislocations and the second phase cause local strain variations within the grains. The Sc-rich segregation at GBs does not affect slip transfer at between adjacent grains and thus has minimal impact on the ductility. Due to the segregation enhancement of grain boundary cohesion, the crack at the grain boundary does not expand significantly even under high strain, which reflects a strong crack coordination ability. Finally, slip systems involved in slip transfer have a higher Composite Schmid Factor (CSF). Compared to the geometric compatibility factor (m(y)), the CSF, which considers local shear stress induced by the input slip system, more accurately explains why slip systems with low Schmid Factor (SF) are activated and better predicts slip transfer behavior in Cu-Cr-Zr-Sc alloys.
10.1016-j.jallcom.2025.183065	14	strength; properties; conductivity; electrical; mechanical; cu-; grain; mpa; electrical conductivity; aging; precipitation; phase; mechanical properties; tensile; phases	Copper sulfides (Cu2-xS) have emerged as promising p-type thermoelectric (TE) materials for mid-temperature applications. Previous research on Cu-S systems has predominantly emphasized elemental doping to reduce thermal conductivity. However, these single-element doping approaches often face challenges in achieving synergistic optimization of TE transport properties, while complex doping strategies bring difficulties for further investigation. In this study, an innovative alloy doping strategy is proposed, utilizing phosphor copper (PCu) alloys as a partial copper source to achieve composition-driven modifications. This approach effectively mitigates the inherent issue of excessive copper vacancies in Cu1.8S. Systematic characterization reveals that phosphorus incorporation induces composition-driven microstructural evolution, characterized by the formation of secondary phases, pores, and dislocations. First-principles calculations further demonstrate that phosphorus doping modifies the electronic band structure of the host matrix and enhances its electrical transport properties. Consequently, the optimized material exhibits a peak TE figure of merit value of similar to 1.32 at 773 K. These findings demonstrate that alloy doping is an efficient strategy for enhancing the performance of Cu-based TE and may serve as a reference for the design of advanced TE materials in other alloy systems.
10.1016-j.jallcom.2025.183105	14	strength; properties; conductivity; electrical; mechanical; cu-; grain; mpa; electrical conductivity; aging; precipitation; phase; mechanical properties; tensile; phases	The miniaturization of integrated circuits in electronic devices has driven the transition of lead frame manufacturing from mechanical stamping to chemical etching, making low residual stress a critical performance requirement alongside high strength and conductivity. In this study, stress relief annealing (150-550 degrees C for 3 min) was performed on C70350 copper alloy strips, with microstructural evolution and macro-texture gradients across both surface and thickness directions characterized by TEM, EBSD and XRD. Results demonstrate that RD residual stress first decreased and then increased with rising annealing temperature, reaching a minimum at 350 degrees C, while TD residual stress minimized at 250 degrees C. Short-term annealing (3 min) at moderate temperatures (250-350 degrees C) effectively reduced residual stresses while maintaining excellent comprehensive properties. Annealing at 350 degrees C and 550 degrees C altered phase boundary relationships, weakening the pinning effect of precipitates on dislocations. In the 150-450 degrees C range, residual stress was jointly influenced by dislocations and precipitates. Furthermore, alternating tensile-compressive stress gradients were observed through the strip thickness after annealing, with Cube texture intensity gradually decreasing from surface to center. The positive correlation between GND density and localized Cube texture content reflects the combined effects of rolling process and moderate-temperature annealing. These findings can provide theoretical guidance for producing copper alloy strips for lead frame applications.
10.1016-j.jallcom.2025.183256	-1		Cu-Ni alloys are versatile materials for various industrial and engineering applications, known for their ability to maintain strength and ductility while possessing desirable chromatic properties. We focused on synthesizing a ductile solid solution of Cu-Ni alloy and incorporating Cr element to modulate chromaticity and to enhance mechanical properties. The influence of Cr content on the microstructure, chromaticity, and mechanical properties of (Cu85Ni15)(100-x)Cr-x alloys was systematically investigated. Microstructural analysis confirmed that phase separation of FCC alpha-Cu and BCC alpha-Cr solid solution phases occurred with increasing Cr content, and the size and morphology of alpha-Cr phase depended on the Cr content. The color difference of alloys evaluated using reflectivity analysis on the CIE L*a*b* color space system confirmed that there was a distinct color difference and the reflectivity, which significantly depended on Cr content and phase separation. The fine and coarse alpha-Cr phases contributed to color variation and improved hardness. The Vickers hardness of these alloys was significantly improved from 73 HV to 113 HV. Moreover, the yield strength and ultimate tensile strength also improved while maintaining large plasticity (similar to 34 %) and high work-hardenability with an increasing volume fraction of alpha-Cr phase. This study highlights the feasibility of designing Cu-based color alloys with expanded chromaticity and improved mechanical properties, offering valuable strategies for applications demanding specific color and material characteristics.
10.1016-j.jallcom.2025.183281	14	strength; properties; conductivity; electrical; mechanical; cu-; grain; mpa; electrical conductivity; aging; precipitation; phase; mechanical properties; tensile; phases	As the critical transmission conductor material used in the field of automotive wiring harness, the microstructure evolution law of CuSn alloy wire and its relationship with properties in the process of fine continuous deformation need to be further clarified. In this study, Cu-0.3Sn alloy wires with a diameter of 0.1 mm were fabricated by vertical continuous casting process combined with the multi-pass cumulative large strain drawing deformation process. The evolution patterns of texture and microstructures were systematically investigated using SEM, TEM, and EBSD, thereby establishing a fundamental correlation between microstructure and mechanical-electrical properties such as ultimate tensile strength and electrical conductivity. Results reveal that when the true strain exceeds 5.99 (Phi 0.38 mm), the electrical conductivity and ultimate tensile strength of the wire exhibit a synchronous improvement trend. Upon reaching a true strain of 8.76 (Phi 0.1 mm), the wire demonstrates exceptional ultimate tensile strength and electrical conductivity, achieving values of 749 MPa and 76.96 % IACS, respectively. The ultimate tensile strength improvement is predominantly governed by solid solution strengthening, grain boundary strengthening, and dislocation strengthening, with additional contributions from the < 111 > texture. Conversely, the reduction in electrical conductivity is primarily attributed to the effects of solid solution atoms and grain boundaries. Nano-microbands and nanotwins formed during continuous deformation effectively decrease the intragranular dislocation density and electron scattering probability, and thus simultaneously improve the ultimate tensile strength and electrical conductivity. The research results can provide support for the fabrication of high-performance complex copper alloy microfilaments and the regulation of microstructure and properties.
10.1016-j.jallcom.2025.183297	-1		Balancing increased recoverable strain with high phase transformation temperature is crucial for Cu-Al-Mn SMAs to cost-effectively overcome the service temperature limitation (<100 degrees C) of NiTi-based SMAs. This study fabricated four types of Cu-12.5Al-3Mn SMAs modified with nano-Al2O3p (0, 0.5, 1.0, and 1.5 wt%) using wire arc additive manufacturing (WAAM) with cored wires. It investigated the effects of nano-Al2O3p on shape memory properties, exploring mechanisms via microstructural, phase, and hardness analysis. Results show that adding an appropriate amount of nano-Al2O3p significantly enhances memory performance while maintaining high martensite transformation temperatures. The 0.5 wt% nano-Al2O3p modified alloy exhibited optimal properties: a shape recovery rate of 87.77 % (13.8 % higher than the base alloy) and a recoverable strain of 7.02 % (>40 % higher than the commonly reported 5 %) under 8 % bending pre-strain. Its Ms temperature remained above 100 degrees C (As, Af, Mf were largely unchanged), and full recovery time was halved compared to the unmodified alloy. The enhancement is attributed to nano-Al2O3p strengthening the parent phase and improving thermoelastic martensite order via pinning. Their high stability under WAAM's high-energy heat source minimizes impact on alloy composition, while dispersed particles create lattice distortion and stress fields, reducing the energy barrier for martensitic transformation.
10.1016-j.jallcom.2025.183312	-1		This study explores the mechanical and microstructural characterization of powder bed fused-laser beam 70/30 CuNi (70 % copper, 30 % nickel), also known as Cu-30Ni, a copper-nickel alloy recently adapted for use in additive manufacturing (AM). 70/30 CuNi is a highly suitable material for applications that demand exceptional strength and high corrosion resistance in salt water at ambient and sub-ambient temperatures. Although 70/30 CuNi is traditionally fabricated through methods such as forging and casting, its application in additive manufacturing (AM) remains in its early stages, with very limited research on powder bed fused-laser beam (PBF-LB). This study addresses such a research gap by investigating the tensile strength and microstructural evolution of PBF-LB 70/30 CuNi in (i) as-built and (ii) heat-treated states, printed at different orientations. Advanced microstructural characterization tools and quasistatic uniaxial tensile tests were employed to establish a correlation between microstructure, mechanical properties (e.g., strength, ductility, and work hardening behavior), and printing orientation (i.e., vertical versus horizontal). A multi-scale hierarchical structure consists of fine cellular structures (elongated and equiaxed) within the coarse grains were identified in nano-, micro-, and macro-levels. It was observed that the horizontally built material demonstrates higher yield stress and ultimate tensile strength, but lower ductility compared to those printed in the vertical direction. We also compared our tensile results against the mechanical properties of commercial (i.e., cast) 70/30 CuNi. This study provides valuable insights into the potential of PBF-LB 70/30 CuNi as an alternative for conventionally fabricated counter material, for various industrial applications (e.g., marine).
10.1016-j.jallcom.2025.183477	-1		In this work, a series of Cu-1.86Ni-1.1Co-0.62Si-0.12Mg-xAg (x = 0, 0.1, 0.5 and 1 wt%) alloys were prepared with multistage thermo-mechanical treatment. The result from tests based on the national standards GB/T 228.1-2021, GB/T 351-2019 shown that the Cu-1.86Ni-1.1Co-0.62Si-0.12Mg-1Ag (wt%) alloy possess the best overall properties, with ultimate tensile strength of 825 MPa, yield strength of 790 MPa, elongation of 3.0 % and electrical conductivity of 46.2 % IACS. While, the Cu-1.86Ni-1.1Co-0.62Si-0.12Mg (wt%) alloy, under optimum aging conditions, with ultimate tensile strength of 734 MPa, yield strength of 679 MPa, elongation of 3.3 % and electrical conductivity of 46.5 % IACS. Considerable efforts were made to reveal the mechanism on the synergistic enhancement of strength and conductivity of Cu-Ni-Si alloys by Ag addition. The addition of Ag contributes to the formation of more nanoprecipitates. The synergistic effect between fine precipitates and high-density dislocations enhances the mechanical properties of the alloy. On the other hand, the addition of Ag promotes the formation of the precipitated phases leading to a decrease in the solute atom content in the matrix, which reduces the electron scattering, and contribute the increase of electrical conductivity.
10.1016-j.jallcom.2025.183481	-1		A fine, uniform and equiaxed grain microstructure is desirable for both cast and wrought alloys, facilitating downstream processing and enhancing their mechanical properties. Here, without changing alloy chemistry, we demonstrate a solidification-control solution via synchrotron mechanical spinning and orbiting of melt, producing high-intensity superimposition shear flow (SSF), to cast metallic alloys with a refined, uniform, and equiaxed grain structure and improved mechanical performance. Using the tin bronze alloy Cu-12Sn-1.5Ni-0.06Fe (wt%) as a model alloy, we employ SSF to achieve almost full transition from bimodal structure of strong columnar grains in edge and coarse equiaxed dendrites in center, to uniform structure of fine and equiaxed dendrites throughout casting Cu samples. This results in an extra high tensile ductility (almost doubled) and a similar to 4 % improvement in tensile strength compared with the conventional casting Cu-12Sn-1.5Ni-0.06Fe. The unique strength-ductility synergy in SSF Cu-12Sn-1.5Ni-0.06Fe is realized through the combined effects of optimized grain structure that alleviate the strain localization and grain boundary cracking, and meantime promote intragranular nanoprecipitation-dislocation interactions and thus durable and considerable strain hardening. Our technique is applicable to other metallic materials that exhibit coarse and non-uniform grain structures during casting.
10.1016-j.jallcom.2025.183483	14	strength; properties; conductivity; electrical; mechanical; cu-; grain; mpa; electrical conductivity; aging; precipitation; phase; mechanical properties; tensile; phases	Through solidification experiments combined with multiple characterization techniques (SEM/TEM/DSC), the microalloying effect of Si was systematically investigated to study the phase transformation mechanisms in Cu-15Ni-8Sn alloy. The results demonstrate that the addition of 0.6 wt% Si significantly lowers the liquidus temperature (Delta T = 10 degrees C) and the eutectic temperature of alpha 1 phase (Delta T = 5 degrees C). During the solidification process, the Si element promotes the formation of the Ni31Si121 phase by consuming a substantial amount of Ni, which consequently lowers the eutectic temperature of gamma 1 phase by 5 degrees C. Notably, the preferential precipitation of the Ni31Si121 phase plays a critical role in nucleation and growth of gamma 1 phase. Furthermore, when the quenching temperature drops below 700 degrees C, small Ni31Si122 and gamma 2 phases predominantly nucleate in the primary microstructure (Ni31Si121 phase-gamma 1 phase), fully suppressing the formation of the typical alpha/gamma lamellar structure in Cu-15Ni-8Sn alloys. These synergistic effects fundamentally alter the solidification path, resulting in a more refined dendritic structure (a 19 % reduction in branch spacing compared to the Cu-15Ni-8Sn alloy at 200 degrees C) and gained excellent microstructure. This work elucidates Si-induced microstructural control mechanisms for designing Cu-Ni-Sn alloys.
10.1016-j.jallcom.2025.183494	6	grain; deformation; strain; strength; dislocation; cu-; tensile; size; ecap; grain size; sfe; ductility; hardening; high; stress	Heterostructure design in metallic materials have attracted considerable attention, especially the dual heterostructures due to the superior combination of strength and ductility. In this study, we prepared dual heterostructures in Cu-4.5 wt%Al alloy via cold rolling and annealing followed by surface mechanical attrition treatment (SMAT). Microstructure characterization and tensile properties were conducted to uncover the microstructure evolution and mechanical properties of dual heterostructures sample. Results demonstrated that the CR-500+SMAT sample with dual heterostructures consisted of a bimodal structure in the center region and a gradient deformation twins and dislocations near sample surface. Noticeably, CR-500+SMAT sample with dual heterostructure exhibited higher yield strength and comparable ductility compared with single gradient structure sample (CR-600+SMAT). Meanwhile, higher heterogeneous deformation-induced strengthening was obtained in the CR-500-SMAT sample due to the existence of abundant interface of dual heterostructures. The high yield strength was attributed to the high-density dislocations and deformed twins induced by SMAT. In addition, the increment of higher low-angle grain boundaries and kernel average misorientation value were observed in the CR-500+SMAT sample after tensile strain of 10 %, which provide higher strain hardening capability. Furthermore, new deformation twins were activated, and dislocations and stack faults were accumulated at the heterogenous interface of coarse grain and fine grain after tensile strain, which maintained good strain hardening capability. The present study provides a feasible strategy for optimizing the mechanical properties by dual heterostructures design.
10.1016-j.jallcom.2025.183639	-1		Magnetic Shape Memory Alloys (MSMAs) are widely recognized for their unique ability to exhibit both magnetocaloric effects and magnetic field-induced strains, making them highly attractive for various applications. The temperature range over which these alloys operate is governed by their characteristic magnetic and structural transition temperatures. As such, it is crucial to understand the factors influencing these transitions, including alloy composition. In particular, the Ni50Mn25-xGa25Cux system has garnered significant attention due to its tunable properties. The composition allows for control over the magnetic transitions occurring in either the martensite or austenite phases, with even slight compositional changes having a considerable impact. Within this context, the aim of the present work is to explore the mechanisms underlying this variability. More specifically, the focus is on the dopant-induced differences in the crystallographic structure. An increasing Cu content is proven to enhance a tetragonal martensite versus a monoclinic one, which is physically seen as the structural transition occurring at higher temperatures. Additionally, the increase in displaced Mn atoms leads to stronger antiferromagnetic exchange interactions, one of the main contributors to TC. Hence, the possibility of tuning the temperature actuation range of the Ni50Mn25-xGa25Cux system, as well as the governing mechanisms, is demonstrated via microstructural differences.
10.1016-j.jallcom.2025.183660	14	strength; properties; conductivity; electrical; mechanical; cu-; grain; mpa; electrical conductivity; aging; precipitation; phase; mechanical properties; tensile; phases	Grain refinement into the nanoscale significantly enhances the mechanical properties of metals and alloys, yet it poses significant challenges in ensuring their thermal stability. Nanograined (NG) materials, which are made up of extremely fine grains, owe their mechanical properties to the dynamics of grain boundaries (GBs). These GBs undergo processes like diffusion, migration, grain rotation, and grain coarsening. However, the specific mechanisms driving these phenomena during thermal annealing remain unclear, particularly for grains in the sub -10 nm range. GB plasticity is critical for determining how these materials behave under stress. It allows NG structures to balance strength and ductility, which is crucial for practical applications in metals and alloys. This study uses molecular dynamics simulations to explore how annealing affects NG aluminum (Al) and copper (Cu). Specifically, it focuses on extremely fine grains between 5 and 8 nm in size and considers the stacking fault energy (SFE) unique to each material. Isothermal annealing under different conditions of time and temperature revealed distinct strengthening-weakening transitions. NG-Al, with its high SFE, demonstrated superior GB relaxation, achieving an increase in yield stress and enhanced resistance to grain coarsening. In contrast, NG-Cu, characterized by low SFE, exhibited significant GB migration and softening due to dislocation activity. Key mechanisms analyzed include GB diffusion, GB migration, grain rotation, and grain coarsening, which underpin the microstructural evolution and mechanical behavior of these materials. This work deepens the understanding of the mechanisms underlying the strengthening-weakening transitions arising from thermal annealing conditions, offering valuable insights for designing ultrahigh-strength and ductile nanograined materials.
10.1016-j.jallcom.2025.183719	-1		In order to obtain high performance (e.g. the tensile strength and elongation) of Cu-W composite, Cu-15 wt% W composite was fabricated by ball milling, spark plasma sintering and subsequent hot rolling. The study investigated the effects of the rolling temperature (650 degrees C, 750 degrees C and 850 degrees C) and the rolling reduction (50 %, 65 % and 80 %) on the microstructures and tensile properties of the composite. This composite rolled at 650 degrees C with the rolling reduction of 65 % exhibits the ultimate tensile strength of 717 MPa and the total elongation of 13.2 %. The ultimate tensile strength of the composite at the optimum hot rolling condition (650 degrees C-65 %) is up to 111 MPa higher than other Cu-15 wt% W samples at other hot rolling conditions, while the total elongation is maintained without significant reduction. The 650 degrees C-65 % condition results in the relatively high proportion of recrystallized grains with the size of 0.27 mu m. The excellent performance of the composites is also attributed to the fine, high-density and diffusely reinforcing nanoscale W particles within Cu matrix. The nanoscale W particles hinder the grain boundaries migration and dislocations movement through the Zener pinning effect. Introducing nanoscale beneficial particles and adjusting hot rolling processes significantly enhance dislocation strengthening and grain refinement in Cu-15 wt% W composite. Our study contributes to the development of W particle-reinforced Cu matrix composites with high strength and ductility.
10.1016-j.jallcom.2025.183720	14	strength; properties; conductivity; electrical; mechanical; cu-; grain; mpa; electrical conductivity; aging; precipitation; phase; mechanical properties; tensile; phases	This study systematically investigated the effects of Cr, Zr and Mg additions combined with thermomechanical processing on grain refinement, precipitation behavior, electrical conductivity, and mechanical properties in CuZn-Ni-Si alloys. The addition of Cr, Zr and Mg maintains the electrical conductivity between 28.60 % IACS and 28.95 % IACS by altering solute scattering, grain boundary density, and dislocation scattering within the alloy. Increased grain boundary density and dislocation scattering partially counteracted solute purification benefits, with stable conductivity maintained through solute-defect scattering modulation. However, more importantly, a dual-phase heterostructure comprising Cr3Si and delta-Ni2Si phases was successfully introduced into the system of microalloyed materials. Thermodynamic competition drove the preferential formation of uniformly distributed Cr3Si phases, which act as heterogeneous nucleation sites to refine and disperse delta-Ni2Si precipitates during aging. The Cr3Si phase enhanced work-hardening capacity by impeding dislocation motion via the Orowan mechanism, while semi-coherent delta-Ni2Si interfaces delayed necking through dislocation storage. On this basis, the microstructural innovations enabled significant concurrent improvements in strength and plasticity. Through synergistic interactions of precipitation strengthening, dislocation strengthening, and grain refinement mechanisms under dual-phase heterogeneous microstructure, the newly developed Cu-8.75Zn-1.2Ni-0.4Si-0.25Mg-0.2Cr0.1Zr-0.1Sn (wt%) alloy demonstrated optimized mechanical properties with yield strength, tensile strength, and elongation reaching 509 MPa, 563 MPa, and 18.50 %, respectively. The optimized alloy exhibits substantial improvements in mechanical properties compared to the counterpart without Cr, Zr and Mg additions, achieving a 14.38 % enhancement in yield strength, 18.0 % increase in tensile strength, and remarkable 117.65 % elevation in elongation. These findings provide a theoretical foundation for designing advanced Cu alloy strips for highperformance connectors in new energy vehicles.
10.1016-j.jallcom.2025.183764	-1		To enhance the mechanical properties of copper alloys and satisfy the operational requirements of copper alloy components in larger thrust rocket combustion chambers, In this study, Cu-Cr-Zr alloy/316 L stainless steel composites with varying compositions were prepared using double-wire laser-arc hybrid additive manufacturing (LAHAM). The mechanism by which 316 L stainless steel influences microstructural refinement and enhances the mechanical properties of composites is elucidated. The results indicated that micrometer- and nanometer-scale Fe phases were precipitated within the composites. These Fe phases provided numerous heterogeneous nucleation sites for the Cu matrix, while spatially impeding the growth of Cu phase grains. As the composition of 316 L increased, the number of heterogeneous nucleation sites also rose, leading to significant grain refinement. Specifically, the 316 L content (wt%) was increased from 10 % to 30 %, resulting in a reduction of the average grain size of the composites from 87.4 mu m to 13.1 mu m, representing a decrease of over 80 %. The microhardness and room temperature tensile strength of the composites increased with the rising content of 316 L. The microhardness value of the 30 % 316 L sample reached 153.3 +/- 15.9 HV. The ultimate tensile strength of the 30 % 316 L is measured at 371.6 +/- 22.0 MPa, which is more than 27 % higher than that of the Cu-Cr-Zr alloy LAHAM. The mechanical properties of the composites are enhanced through fine-crystal strengthening, solid solution strengthening resulting from the diffusion of Ni elements to form Cu-Ni solid solution, and dispersion strengthening due to the distribution of nanoscale Fe phases within the Cu matrix, among which fine-crystal strengthening and solid solution strengthening are the most dominant.
10.1016-j.jallcom.2025.183876	14	strength; properties; conductivity; electrical; mechanical; cu-; grain; mpa; electrical conductivity; aging; precipitation; phase; mechanical properties; tensile; phases	In saline environments, corrosion of copper alloys is frequently aggravated by micro-galvanic interactions and selective leaching, with dezincification being especially critical in Cu-Zn systems. This study investigates the corrosion behavior of Cu-Zn and Cu-Al-Zn alloys produced via mechanical alloying and hot pressing at 500 degrees C under 500 MPa. Electrochemical testing in a 3.5 wt% NaCl solution revealed that Cu-Al-Zn alloys possess significantly higher corrosion resistance than both Cu-Zn alloys and pure copper. The addition of aluminium effectively suppressed dezincification by facilitating the formation of adherent passive films of Cu2O, ZnO, and Al2O3 and stable intermetallic compounds, including Cu9Ala and Cu5Zn8, which limited zinc dissolution and enhanced electrochemical stability. Microstructural analysis indicated the presence of refined dual-phase morphologies along with high densification, reaching up to 97.2 %. A maximum hardness of 8.25 GPa was obtained in alloys containing higher aluminium and zinc levels, primarily due to solid solution strengthening and the formation of hard intermetallic phases. The findings highlight that compositional optimization coupled with microstructural refinement provides an effective strategy for mitigating dezincification in copper-based alloys, enhancing their suitability for aggressive marine and structural applications.
10.1016-j.jallcom.2025.183926	-1		Cu-15Ni-8Sn (wt%) undergoes multiple concurrent phase transformations during ageing, which strongly influence its mechanical properties. Here, high-resolution synchrotron X-ray diffraction is utilised to study the microstructural changes that occur during ageing at 395 degrees C. Diffraction signals associated with spinodal decomposition, metastable ordering to form gamma-γ′ and gamma-D022 precipitates, and discontinuous precipitation of gamma-D03 and S-D0a phases are identified and their temporal evolution monitored. Quantitative analyses of the diffraction data reveal that the characteristic wavelength of the spinodal microstructure exhibits a power-law time dependence, consistent with the Lifshitz-Slyozov-Wagner (LSW) theory of particle coarsening. Precipitation of gamma is observed to precede that of gamma, while gamma is progressively replaced by S in the later stages of ageing. The total volume fraction of discontinuous precipitation is well described by the Avrami model for nucleation and growth . Asymmetric diffraction peak profiles observed in the unaged condition are attributed to coherency strains arising from quenched-in elemental clustering, as detected by atom probe tomography. Collectively, these findings offer insights into the interplay between spinodal decomposition, metastable ordering, and discontinuous precipitation in this alloy.
10.1016-j.jallcom.2025.183979	-1		The arc erosion-resistance of electrode materials is critical to the performance of high-power gas switches. Traditionally, the W-Cu alloys are used as erosion resistant electrodes in these switches. However, these materials cannot meet the ever-rising demand of long-lifetime switches in the development of pulse power technology. In this paper, we prepared a bicontinuous Cu-45RHEA composite consisting of Cu matrix and a network of refractory high entropy alloy (RHEA) via liquid metal dealloying. The arc erosion properties of Cu-45RHEA composites as high-power gas switch electrode materials were studied using a single-stage equivalent test circuit of linear transformer driver. We find that the bicontinuous Cu-45RHEA composite electrode shows superior arc erosion resistance and higher self-breakdown voltage, comparing to the commercial 90WCu alloy. The volume loss is reduced by over 60 %, and the self-breakdown voltage is enhanced by approximately 8 %, when the 90WCu alloy is replaced by Cu-45RHEA composite under the same arc erosion conditions. Further analysis reveals that the arc erosion of Cu-45RHEA composite is dominated by Cu evaporation, unlike 90WCu alloys whose erosion is mainly controlled by the splashing of W (or W-rich) droplets. The fine structure size and the well-interconnected RHEA phase might account for the unique erosion behavior and the improved arc erosion resistance of Cu-45RHEA composite.
10.1016-j.jallcom.2025.184125	14	strength; properties; conductivity; electrical; mechanical; cu-; grain; mpa; electrical conductivity; aging; precipitation; phase; mechanical properties; tensile; phases	Body-centered cubic (BCC) lattice structures fabricated by selective laser melting (SLM) possess high specific strength, stiffness, and energy absorption, rendering them attractive for multifunctional load-bearing applications. However, premature failure caused by stress concentrations at nodal junctions and manufacturing defects in the struts often undermines their structural integrity. Cu-Sn alloys, especially Cu-10Sn, were chosen owing to their excellent wear resistance, thermal and electrical conductivity, and broad use in industrial components such as diamond tools and electronic devices. This study employes inverse finite element analysis to calibrate the material parameters of SLM-processed Cu-10Sn struts within BCC lattices and analyze their deformation mechanisms. The developed calibration method greatly improved simulation accuracy, reducing the mean relative error from 46.83 % to 6.54 %. Under compression, low-stress regions persisted near middle of struts, while nodal stress concentrations led to the formation of oblique bands that developed into global X-shaped shear localization patterns. To alleviate stress concentration, a tapered gradient design, controlled by parameter beta, was introduced to shift stresses toward middle of struts. Simulations demonstrated optimal performance at beta = 0.5, with specific modulus, specific strength, and specific energy absorption increasing by 39.63 %, 33.19 %, and 44.73 %, respectively, compared to uniform-strut architectures. This tapered configuration promoted layerby-layer collapse via transverse compression bands, replacing X-shaped shear localization failure. The proposed methodology is applicable beyond Cu-Sn alloys to other metallic lattice systems, offering a viable integration of high-fidelity parameter identification and graded structural design for fabricating reliable, highperformance lattice components.
10.1016-j.jallcom.2025.184203	14	strength; properties; conductivity; electrical; mechanical; cu-; grain; mpa; electrical conductivity; aging; precipitation; phase; mechanical properties; tensile; phases	Four groups of Cu-Ni-Al-Si and six groups of Cu-Ni-Al-Fe diffusion couples were prepared, and the concentration distributions within the diffusion layers formed between 1173 K and 1273 K were measured. Using the obtained concentration profiles, the interdiffusion coefficients and mobility descriptions for the face-centered cubic (FCC) Cu-Ni-Al-(Si, Fe) systems were determined through the numerical inverse method in a high-throughput manner. The impact of compositions on the interdiffusion coefficients and relative diffusion rates within the specified composition and temperature ranges was analyzed. Subsequently, the established mobility description was utilized to simulate the solidification and homogenization heat treatment processes in Cu-10Ni-3Al (wt%), Cu10Ni-3Al-1Fe (wt%), and Cu-10Ni-3Al-1Si (wt%) alloys. The simulated concentration distribution of solutes over the dendrites indicated that Ni and Fe exhibited intra-dendrite segregation, while Al and Si demonstrated inter-dendrite segregation. The inclusion of Fe in Cu-10Ni-3Al alloys slightly increased chemical segregation, whereas the introduction of Si led to the formation of the Ni2Si phase. The addition of Fe had a minimal impact on the annealing times required to eliminate chemical segregation, while the incorporation of Si reduced the annealing times.
10.1016-j.jallcom.2025.184474	-1		Duplex Cu-Zn alloy is widely used in the electronics and precision instrument industries due to its excellent corrosion resistance and electrical conductivity. However, its formability is greatly affected by the n-phase fraction, and it is important to reveal the influence of the n-phase fraction on its mechanical properties and formability. In this study, a combined Holmberg uniaxial tensile and Nakazima testing platform for mesoscale forming based on the digital image correlation was established. Different n-phase fractions were obtained by the various heat treatment temperatures, and the influence of n-phase fraction on the forming limit of the duplex CuZn alloy was revealed. In addition, a new unified dislocation density constitutive model considering the n-phase fraction was proposed, which was combined with the Marciniak-Kuczynski (M-K) model to predict the mesoscale forming limit curve of the duplex Cu-Zn alloy. The results indicated that the n-phase fraction increased from 20.2 % to 41.3 % with the heat treatment temperature increasing from 550 degrees C to 750 degrees C. However, its forming limit curve and plastic deformability showed a declining trend with the strength of the duplex Cu-Zn alloy increased. The formability of material showed a more significant change under equibiaxial tensile, with the maximum average major strain decreasing under uniaxial tensile and equibiaxial tensile decreasing by 16.7 % and 25.0 %, respectively. Furthermore, the proposed constitutive model had an accuracy of 95 % in predicting the mechanical properties of the duplex Cu-Zn alloy. Combined with the M-K model, the average prediction error of the forming limit of the duplex Cu-Zn alloy was less than 5 %. This study provides a research basis for the wide application of duplex Cu-Zn alloys in the field of mesoscale forming.
10.1016-j.jallcum.2022.166102	-1		The trade-off between strength and ductility of structural materials has been the subject of research for a long time. Designing heterogeneous structures is considered to be a promising and suitable strategy to improve the mechanical properties, including both the strength and ductility. In this work, we fabricated a laminated Cu/Cu-6Al alloy by powder metallurgy technique. The laminated Cu/Cu-6Al alloy possesses a graded interfacial region with the width of similar to 50 mu m due to the diffusion of elements during sintering and hot rolling. The graded interfacial structure can effectively relieve the stress concentration at the interface by coordinating multiple deformation mechanisms from dislocation activity to deformation twinning, and thus provide continues working hardening ability. The laminated Cu/Cu-6Al alloy possesses a combination of high strength and large ductility. This work provides a new concept to design high-performance structural materials by forming graded interfaces.
10.1016-j.jas.2014.01.029	2	corrosion; surface; film; electrochemical; films; spectroscopy; layer; current; solution; potential; resistance; composition; x-ray; ions; showed	The objective of this study is to provide insight into the origin of the lead present in the 10th-century. AD Islamic city of Madinat al-Zahra, both as unalloyed metal and as a component of the copper-based alloys, as well as a first approach to technological details related to the production of these materials. Recycling lead is argued to be a common practice but, nonetheless, the lead isotope analysis suggests a single origin for all the lead at the site. Two main options are discussed as lead sources: mines in the Linares district (100 km east) or in Villanueva del Duque (75 km north). Other interesting features are the use of lead-tin solder and fire gilding on a copper zinc alloy.
10.1016-j.jas.2017.04.002	2	corrosion; surface; film; electrochemical; films; spectroscopy; layer; current; solution; potential; resistance; composition; x-ray; ions; showed	The presence or absence of use-wear marks on copper (Cu)-alloy weaponry has been used since the late 1990s to investigate the balance between functional (combat) and symbolic (value, status, religious) use of these objects, and thus explore their social and economic context. In this paper, we suggest that this work has not taken sufficient account of the material properties of Cu-alloys. We discuss mechanisms of plastic deformation, incremental repairs and corrosion in detail to show how these can obscure use-wear traces. In a survey of Cu-alloy weaponry from the Nordic Bronze Age (1800/1700-550 BCE) from Denmark, Sweden and Germany, we show that corrosion of Cu-alloy objects is strongly linked to depositional context, being greater in burials (both inhumations and cremations) than hoards or as single objects. A relative paucity of use-wear marks on burial weapons should therefore not be used to argue that these were purely symbolic objects, e.g. in contrast to the better preserved hoard material. We propose that use-wear traces on Cu-alloy weaponry, particularly on blade edges, is significantly more elusive than previously realised, and that undamaged objects have been over-identified.
10.1016-j.jas.2017.12.001	2	corrosion; surface; film; electrochemical; films; spectroscopy; layer; current; solution; potential; resistance; composition; x-ray; ions; showed	The aesthetic appearance of metals has long been recognised in archaeometric studies as an important factor driving inventions and innovations in the evolution of metal production. Nevertheless, while studies of ancient gold metallurgy are well supported by modern research in colour characteristics of gold alloys, the colour properties of major prehistoric copper alloys, such as arsenical copper and tin bronzes, remain either largely understudied or not easily accessible to the western scholarship. A few published studies have already indicated that alloying and heat treatment change the colours of copper alloys, although they are mainly based on examples of prehistoric tin bronze objects and experimental casts. Here we present a procedure for building the Cu-As-Sn ternary colour diagram, starting with experimental casting of 64 binary and ternary alloys in this system. We used two types of information to produce two different ternary colour diagrams: one based on photographs of the samples, and the other based on the colorimetric measurements. Furthermore, we developed a procedure for creating a graphic representation of colours in the Cu-As-Sn ternary diagram using QGIS. As an initial case study, we plotted the composition of the world's earliest tin bronze artefacts; the graphic representation further supports claims about the importance of a golden hue for their invention and demand, c. 6500 years ago. We argue that the presented colour diagrams will find wide use in future investigations of aesthetics of prehistoric copper alloys.
10.1016-j.jas.2018.02.016	2	corrosion; surface; film; electrochemical; films; spectroscopy; layer; current; solution; potential; resistance; composition; x-ray; ions; showed	Cu isotope characterization of copper-based artifacts is a powerful tool used in recent decades to investigate the types of ore smelted in ancient metal production. Within a larger sample set, Powell et al (2017) have identified a shift from positive delta Cu-65 values obtained for Eneolithic artifacts in the Balkans (5000-3600 BC) to more moderate and negative delta Cu-65 values of Bronze Age artifacts (2500-1000 BC), with a so-called copper hiatus between these two periods. Powell et al concluded that accessible oxidized ore sources in this region were totally exhausted by the end of the Eneolithic period, directly leading to a hiatus in copper production. After the hiatus, starting with the Early Bronze Age, they proposed that sulfide ores were smelted using the Mitterberg process. The current paper addresses some weaknesses of the arguments put forth by Powell et al and instead argues that Cu isotope ratios must be jointly considered with additional archaeometallurgical and archaeological investigations. Selective changes in preference for metal alloys likely affected the Cu isotope composition. Metallurgical operations using distinct Cu isotope reservoirs can alter the univariate Cu isotope ratio (Cu-65/Cu-63). Key points that must be considered are the transition from pure copper in the Eneolithic to arsenical copper in the Bronze Age, the co-smelting of distinct ore types, and the co-melting of metals derived from multiple smelting operations or from re-used metal artifacts. Moreover, there is no archaeological evidence for the Mitterberg smelting process in the Balkans during the Early Bronze Age.
10.1016-j.jas.2020.105199	-1		The colour of jewellery objects is decisive for the appearance of the object. For this reason, a system was developed for this paper in order to deduce the colour of the copper alloys based on the chemical composition of the object. For this purpose, 424 copper alloys were produced in the copper-tin-zinc-lead system. The colours in this system range from copper tones to gold and silver tones with different intermediate levels. Lead has the least influence in the system. If tin and zinc are used in the alloy, lead still only has a minor influence. The greatest colour variance is found in the copper-tin-zinc system. Furthermore, the results of the colour measurements are applied to selected archaeological examples.
10.1016-j.jcis.2008.06.041	-1		The article reports on a very simple method to fabricate superhydrophobic surfaces with Cu-Zn alloy via changing the local oxygen concentration and formation of oxygen difference cell, which can be readily realized by covering or contacting the Cu-Zn alloy surface with a glass slide. This superhydrophobic film comes from the formation of a flower-like hierarchical Structure due to the accelerated alloy etching. contrast, the white film grown in the un-covered area showed a Much lower hydrophobicity due In. to its different morphology. These superhydrophobic surfaces OF superhydrophobic-hydrophobic surfaces are expected to find applications in making self-cleaning alloy surface, in metal anticorrosion, and in biomineralization, etc.
10.1016-j.jcis.2014.11.052	-1		Uniform surfactant-free copper selenide (Cu2-xSe) nanowires were prepared via an aqueous route. The effects of reaction parameters such as Cu/Se precursor ratio, Se/NaOH ratio, and reaction time on the formation of nanowires were comprehensively investigated. The results show that Cu2-xSe nanowires were formed through the assembling of CuSe nanoplates, accompanied by their self-redox reactions. The resultant Cu2-xSe nanowires were explored as a potential thermoelectric candidate in comparison with commercial copper selenide powder. Both synthetic and commercial samples have a similar performance and their figures of merit are 0.29 and 0.38 at 750 K, respectively.
10.1016-j.jclepro.2016.11.017	-1		This study investigates and verifies the selective thermal transformation of metals within e-waste to; achieve for the first time the direct, production of value-added Copper-Tin (Cu-Sn) nanoparticles and the simultaneous separation out of toxic Lead (Pb). Electronic waste (e-waste) is one of the world's fastest growing and most challenging solid waste streams, due to its complex mix of metals, plastics, ceramics and hazardous components, but, at the same time, it contains a wealth of valuable embedded resources. Current resource recovery and recycling methods are inadequate; industrial scale recycling is expensive and incomplete and leaving significant problematic residue. At the same time the informal e-waste processing in developing countries exposes poor communities to contaminants. Alternative approaches are urgently needed. In this work outdated, older generation printed circuit boards (PCBs), which currently contaminate the world's waste stock piles, has been used. Investigating the thermal transformation mechanism using SEM and TEM, have shown Sn-Pb alloy present in the waste began to melt at 900 degrees C and due to high wettability of the alloy on Cu; it covered the Cu particles present. The diffusion of Sn into the Cu was subsequently triggered, due the high solubility of Sn in Cu, while the Pb was separated out due to the low solubility of Pb in Cu. The plastics in the waste generated a reducing environment which acted as a 'thermal micronizing' media and protecting the nanoparticles from oxidation, while Carbon minimized agglomeration. The results reported here critically address and detail a novel pathway for safely transforming problematic e-waste into value added resources, via a 'thermal micronizing' process.
10.1016-j.jclepro.2018.06.029	16	wear; composite; composites; powders; milling; particles; powder; wt; sliding; friction; hardness; matrix; mechanical; surface; properties	Fly ash (FA), the solid waste resulting from combustion of coal in thermal power plants is a by-product produced in massive quantities across the world. It is considered as an environmental pollutant. Owing to its bad effects on the environment, research is being conducted all over the world for the utilisation of FA. The present work emphasizes the utilisation of FA as reinforcement in copper based surface composite fabricated by friction stir processing (FSP). The properties of fabricated composite and its environmental impact through leaching test have also been reported in the present study. A groove of known dimension was machined at the centre of the plate (6 mm thickness) for compaction of the high amount of FA (almost 18 vol %), processed by FSP. The microstructural features of the fabricated composite were observed by optical and scanning electron microscope revealed equiaxed and fine grain structure with no concentration gradient, agglomeration and segregation along the grain boundary. The stir zone (SZ) was engulfed with particulate along with clean interface and excellent bonding. The XRD pattern revealed no intermetallics or in situ products except copper and particulate. Vickers microhardness tester machine adjudged significant improvement in hardness. The composite showed higher tensile strength and lower ductility as compared to copper. Enhancement in oxidation and corrosion resistance was also observed whereas electrical conductivity decreased as evaluated by four probe method. The pin on plate unidirectional dry sliding wear test was performed to evaluate the wear loss. The wear resistance of the fabricated composite improved substantially. The worn surface was observed by scanning electron microscope to have a detailed understanding of wear mechanism. Further through leaching test, it was observed that concentration of leached out metals was far below as specified in Indian legislation.
10.1016-j.jclepro.2018.07.140	-1		This paper details the synthesis of copper-based products (i.e. Cu, Cu-Ni-Sn, Cu-Sn) from printed circuit boards (PCBs) using thermal transformation at 500 degrees C. The temperatures investigated in this paper are much lower than those used in conventional electronic waste smelting industries. This helps in reducing the energy requirements of the process opening up pathways for sustainable PCB processing technology. The resulting copper-based product comprises up to 94% metallic Cu, 2.5% Cu-Ni-Sn and 0.7% Cu-Sn alloys. Metallic Cu and Cu-Ni-Sn alloy are present in face centered cubic (FCC) form whereas Cu-Sn alloy possesses hexagonal closed packed (HCP) structure. XPS attests complete absence of oxides in metallic Cu. The copper product exhibits 4.57 x 10(7) +/- 0.084 S m(-1) electrical conductivity, equivalent to 78% IACS (International Annealed Copper Standard), which potentially enables its application in electrical switches or wire terminals. We have thus successfully developed a copper-based product from electronic waste, studied its properties and explored it from an application point of view.
10.1016-j.jclepro.2022.130431	2	corrosion; surface; film; electrochemical; films; spectroscopy; layer; current; solution; potential; resistance; composition; x-ray; ions; showed	The release of pollutants from bacterial pathogens in air or water, which causes a serious threat to human health and well-being. Traditional antibiotics have exhibited insufficient ability in combating bacteria owing to the emergence of drug-resistant bacteria. Hence, effective antibacterial candidates urgently need to be explored as an alternative for overcoming the antibiotic barrier. It is highly necessary to find an effective stable disinfection system with the nature of environmental-friendly, high activity and stability, convenient synthesis procedure, low energy, cleaner, and low economic consumption. Considering these aspects, optical strategy and chemical treatment bring convenience and advantages in bacterial inactivation. In this work, the bimetallic Cu-Bi alloy was explored using a simple one-pot solvothermal strategy. On the one hand, the bimetallic structure can prevent copper from oxidation to decrease potential secondary pollution activity caused by excessive release of copper ions, and maintain copper's highly biological activity. On the other hand, the as-prepared Cu-Bi alloy was employed to perform antibacterial applications. Hyperthermia is driven by near-infrared light and the introduction of ROS from Cu Fenton-like reaction that can effectively promote the death of bacteria, and perform a better antibacterial ability than that of single Ag + or Cu2+ release, resulting in the significant growth inhibition of E. coli. Overall, the combination of the multiple disinfection ability of the Cu-Bi alloy, involving highly efficient ROS generation and effective photothermal performance, not only shows the potential in fighting against pathogenic bacteria but also provides an important insight for the exploration of antibacterial platforms based on the bimetallic materials.
10.1016-j.jcrysgro.2004.11.374	-1		This paper describes the use of diffraction to experimentally characterize a directionally solidified Cu-Cr eutectic alloy containing sub-micron diameter Cr whiskers. This material has been analyzed in terms of its texture and thermal residual elastic strains as measured by neutron diffraction. Observations of the defect structure of the material and the crystallographic relationship between phases are also made. It is observed that the Cr phase in the directionally solidified material is similar in morphology and crystallographic orientation relationship to Cr precipitates formed in the solid state.
10.1016-j.jcrysgro.2006.10.105	2	corrosion; surface; film; electrochemical; films; spectroscopy; layer; current; solution; potential; resistance; composition; x-ray; ions; showed	The chalcopyrite copper iron sulphide films, CuFeS2, have been grown in thin films' form by sulphurization of CuFe alloy precursor. ;Cu/Fe.../Cu thin layers have been sequentially deposited by vacuum evaporation on a substrate heated at a temperature T-s = 723 K. After deposition of the metal alloy precursor, there is an interdiffusion of the metals all along the thickness. The relative thicknesses of the layers deposited were calculated to achieve the desired atomic ratio Cu/Fe: 2.5. These precursors are sulphured in a vacuum chamber using an S source. The sulphurization duration is 20 min. At the end of the process, the film exhibits a (112) preferential orientation. Thus, the structure of the film is the expected tetragonal structure of CuFeS2. The XPS study shows that there is no oxygen contamination of the film, except the surface because it has been exposed to air. The composition measured is in good agreement with that measured by electron microprobe analysis.
10.1016-j.jcrysgro.2008.10.033	4	transformation; martensite; martensitic; phase; shape; beta; memory; shape memory; temperature; temperatures; martensitic transformation; gamma; transformation temperatures; effect; thermal	Microstructures forming in the Cu-Sn system with alloy compositions close to the metatectic composition are characterized. A careful experimental procedure with a variety of holding temperatures and cooling rates allows for unambiguous interpretation of the solidified microstructures. The decay of the high-temperature gamma-phase according to the metatectic reaction gamma ->epsilon+liquid could not be suppressed even by the highest available quenching rates. Different microstructural features are observed concerning the secondary epsilon-phase. For low and moderate cooling rates, epsilon is growing ill columnar grains, surrounded by peritectic eta-phase. For rapid quenching, secondary epsilon partially remelts and exhibits fine globulitic particles of eta.
10.1016-j.jcrysgro.2009.03.030	-1		Assuming thermal balance and solute conservation, a numerical model has been proposed to describe the recalescence behavior of bulk-undercooled Cu-Ni melts. Applying a finite-difference scheme, the transformed solid fraction upon recalescence is given as a function of the liquid temperature, while the average liquid concentration can be tracked by calculation of the liquid/solid (L/S) Gibbs energy difference, in combination with a dendrite growth model. Accordingly, a transition from non-equilibrium to equilibrium process has been described from the evolution of L/S Gibbs energy difference. Applying the present model, the experimentally observed maximum recalescence temperature can be well predicted.
10.1016-j.jcrysgro.2011.05.015	-1		The crystal-melt interfacial free energy and its small anisotropy were computed using molecular dynamics simulations and the capillary fluctuation method applied to an embedded atom description of the ternary Cu-Ag-Au alloy system. The use of a ternary system allows for an assessment of the variation in anisotropy as one solute species (Au) is replaced by a nearly equal atomic size species (Ag) at a constant temperature, thereby isolating the effect of solute-solvent binding characteristics. Both the four-fold anisotropy parameter, epsilon(1), and the six fold term, epsilon(2), were computed for five compositions within the Gibbs triangle at T = 1275 K. The results suggest that solute species exhibiting a large enthalpy of mixing will tend to promote a transition of the dendrite crystallographic growth directions from < 1 0 0 > to < 1 1 0 >.
10.1016-j.jcrysgro.2011.12.083	-1		The effect of the growth velocity on the microstructure evolution of Cu-1.54 wt% Cr alloy under directional solidification was investigated. The cellular eutectic structure was observed at 50 mu m/s. However, a centered Cr-rich beta dendritic structure surrounded by a layer of Cu-rich alpha phase and a eutectic structure between Cu-rich alpha phase and Cr-rich beta phase were observed when a sample solidified at a rate faster than 50 mu m/s. A microstructure of a centered Cr-rich beta equiaxed dendritic structure covered by a Cu-rich alpha phase grew at temperatures higher than the eutectic interface temperature. This paper explains the mechanism of the microstructure formation as a function of growth velocity.
10.1016-j.jcrysgro.2013.11.019	2	corrosion; surface; film; electrochemical; films; spectroscopy; layer; current; solution; potential; resistance; composition; x-ray; ions; showed	The structure and chemical composition of Cu1-xZn1-ySe2-delta (Cu-Zn-Se) ternary alloy semiconductors were examined by transmission electron microscopy (TEM) coupled with energy dispersive X-ray spectroscopy (EDS), a TEM/EDS analytical technique. Polycrystalline Cu-Zn-Se thin Films were prepared by atmospheric pressure metal-organic chemical vapor deposition. The TEM/EDS technique has made an elemental analysis focused on a microscopic region possible. Therefore, the spatial distribution of constituent elements of Cu-Zn-Se polycrystal within both grains and grain boundaries could be investigated and the compound stoichiometry was evaluated. Conclusively, the cross-sectional TEM images characterized the fabricated Cu-Zn-Se layers as a polycrystalline Film of about 70-80 rim thick and composed of grains with sizes ranging from 0.3 to 1.7 mu m. The chalcopyrite structure of Cu-Zn-Se Films was confirmed by the selected area electron diffraction patterns. Moreover, the EDS point analyses conducted at optionally chosen positions showed quite comparable chemical compositions for the grains examined, yielding an average composition ratio of about 0.92:1.44:2 for Cu:Zn:(Se + O) within grains. However, the replacement of Cu atoms for Zn atoms in elemental composition was found at grain boundaries, resulting in an average composition ratio of about 1.26:1.24:2 for Cu:Zn:(Se + O) over there. It is suggested that the enhanced diffusion of Cu along the grain boundaries and the segregation of Cu to the grain boundaries increase the mean composition of Cu at these paths. (C) 2013 Elsevier B.V. All rights reserved,
10.1016-j.jcrysgro.2017.02.019	2	corrosion; surface; film; electrochemical; films; spectroscopy; layer; current; solution; potential; resistance; composition; x-ray; ions; showed	The CVD method was employed to synthesize nanoobjects of Cu-Si phases at temperature of about 500 degrees C. Cu/Cu5Si-substrates and various Si-containing precursors (SiH4, EtSiH3, BuSiH3) with/without added H-2 or air were used. Nanoobjects of various morphologies (nanoplatelets of eta'-Cu3Si, nanoribbons and nanorods of eta'-Cu3Si, and nanowires of gamma-Cu83Si17) were obtained depending on the experimental conditions, mainly type and pressure of precursor. A mixture of Si-containing precursor and H-2/air promotes the growth of nanoobjects compared to using the pure Si-containing precursor. With increasing pressure of precursors the morphology changes from 1D (nanowires) to 2D (nanoribbons, nanoplatelets). Nanoobjects grow via the non-catalytic VS mechanism.
10.1016-j.jcrysgro.2019.03.019	0	solidification; phase; magnetic; magnetic field; undercooling; field; liquid; separation; peritectic; immiscible; cu-; dendrite; phase separation; microstructure; primary	The effects of high magnetic field on the microstructure evolution of non-equilibrium solidified Cu80Co20 alloy have been investigated by glass fluxing combined with cyclic superheating and cooling method in a superconducting magnet. Results show that both the undercooling and magnetic field can affect the microstructure of Cu80Co20 alloy. The size of Co-rich phase increases with the enlarged undercooling. The Co-rich particles are elongated along the direction of 6 T magnetic field while these granules become more dispersed perpendicular to the direction of 6 T magnetic field. Moreover, the volume fraction of Co-rich phases perpendicular to the 6 T magnetic field reduces significantly.
10.1016-j.jcrysgro.2019.125382	0	solidification; phase; magnetic; magnetic field; undercooling; field; liquid; separation; peritectic; immiscible; cu-; dendrite; phase separation; microstructure; primary	Molecular dynamics simulations are performed to study the solidification process of Cu melt in confined nanoslits (NSs) constructed by graphene sheets. Results shows the interactive influence of the nanoslits size and cooling rate on the solidification of confined Cu melt. With the increase of nanoslits size, the stable solidified structure will change from the initial {1 0 0}-oriented to {1 1 1}-oriented. It is found that increase of the cooling rate can promote this structural evolution. Besides, effect of cooling rate on the solidified structures of Cu melts deeply depends on the nanoslits size. At the cooling rate of 10 K/ps, 26 A may be the optimal size of the nanoslits to obtain the most ordered crystal structure. With further increase of the cooling rate, decrease of the size will obviously weaken the effect on the solidified structure and enhance the order degree of atomic arrangement. Our findings provide new evidence on the fabrication of controlled nanostructures by means of nanocasting in metal.
10.1016-j.jct.2012.07.025	12	thermodynamic; ternary; phase; data; experimental; equilibria; phase equilibria; liquid; binary; experimental data; calculated; phases; literature; model; calphad	A new thermodynamic description of the binary (Cu + Si) system is proposed based on available experimental data. According to the newest information, the phases d and c were treated as phases with a polymorphic transformation at T = 1008 K. The polymorphic transformation of the g phase was also modelled. The liquid phase was described by the associated solution model. Besides optimization of the phase diagram and thermodynamic function, the atomic mobility in a face centred cubic lattice was assessed. Good agreement between calculations and experimental results was found.
10.1016-j.jct.2020.106172	12	thermodynamic; ternary; phase; data; experimental; equilibria; phase equilibria; liquid; binary; experimental data; calculated; phases; literature; model; calphad	The phase equilibria of the Cu-Ag-Si system were investigated by a combination of key experiments and thermodynamic modeling. Eighteen ternary alloys were prepared to determine the isothermal sections at 500, 600, and 700 degrees C of the Cu-Ag-Si system by means of X-ray diffraction (XRD) and scanning electron microscopy with energy dispersive X-ray spectroscopy (SEM/EDX). The solubilities of Ag in the Cu19Si6, Cu15Si4, Cu56Si11, and hcp(CuSi) phases were measured. No ternary compound was found in this isothermal sections. Based on the experimental equilibria data from the present work, thermodynamic assessment of the Cu-Ag-Si system was carried out by the CALPHAD (CALculation of PHAse Diagrams) approach . The solution phases (Cu), (Ag), (Si), and hcp(CuSi) were described using substitutional solution model and the binary phases Cu19Si6, Cu15Si4, and Cu56Si11 with the solubility of Ag were modeled by the sublattice models. A set of self-consistent thermodynamic parameters of the Cu-Ag-Si system was obtained. The isothermal sections at 500, 600, 650, and 700 degrees C, vertical sections at 10 and 20 at% Ag, and liquidus projection were calculated. The reaction scheme of the Cu-Ag-Si system was constructed. The calculated results are in agreement with the experimental data from the present work and literature. (c) 2020 Elsevier Ltd.
10.1016-j.jddst.2021.102384	2	corrosion; surface; film; electrochemical; films; spectroscopy; layer; current; solution; potential; resistance; composition; x-ray; ions; showed	This study reveals a cost-effective route (mechanical alloying) to synthesize an antibacterial drug conjugated copper-silver-titanium oxide nanocomposite (10 wt% cefixime conjugated Cu-Ag-TiO2) for successful targeting of the drug with enhanced antibacterial activity. For the nanocomposite (NC) and drug conjugated nano composite (NC-DC), detailed structural and microstructural characterizations have been carried out by analyzing the FESEM-EDS spectra, TEM images, and the Rietveld refinement of the XRD patterns. The NC-DC sample is completely biocompatible, as reflected by the MTT assay. The Antibacterial activity of the samples has been investigated by agar cup diffusion assay and minimum inhibitory concentration (MIC) studies. These studies indicate that the NC sample itself has significant antibacterial activity and NC-DC sample has four times greater antibacterial activity than the pure drug cefixime, as again supported by fluorescence microscopic studies. The mode of action of NC and NC-DC samples has been investigated in detail employing conductivity measurement and total protein leakage assay. The significant enhancement of the antibacterial activity of the drug seems to be very important for an antibacterial drug, as a low dose of the conjugated drug would result in better antibacterial activity with minimal side effects.
10.1016-j.jece.2024.115231	-1		Clean and efficient extraction and separation of valuable metals from Cu-Zn alloy scrap is important for the efficient treatment of solid waste resources. Due to the good plasticity and toughness, the alloyed material is difficult to fine grind to meet the particle requirements for hydrometallurgical leaching. In the industrial leaching process, the coarse and dense alloyed particles are often deposited at the bottom of reactor owing to the greater gravity, resulting in low metal leaching efficiency. In this work, the acid leaching behaviors of multi metals of Cu, Zn, Pb, Ni, and Sn from Cu-Zn alloy scraps with different particle size distributions in the conventional and ultrasound-assisted leaching processes are investigated and compared. Based on the metal activity difference between Cu and Zn, 94.05 % Zn was preferentially extracted in 0.75 mol/L HNO3 for 180 min, and 94.23 % Cu was further rapidly dissolved in 2 mol/L HNO3 with the ultrasound assistance for 25 min, realizing the separation of Cu and Zn. Meanwhile, 95.23 % Pb and 70.51 % Ni were simultaneously transferred into the Zn leachate. After these metals extraction, 84.22 % Sn was enriched in the last residue and can be completely leached in 8 mol/L HCl. The acoustic wave field distribution in a rectangular reactor was quantitatively measured, and the intensifying dissolution mechanism of coarse and dense particles by ultrasound assistance was also clarified in this work. On the one hand, the ultrasonic cavitation effect contributed to surface crack propagation on coarse particles and facilitated the penetration of HNO3 into the interior of dense particles. On the other hand, the unique reflection and cumulative effects of ultrasound in a finite field were extremely favorable to the suspension movement and dissolution of large particles. Eventually, the ultrasound-assisted leaching technology and strengthening mechanism proposed in this study were applicable to the fast extraction and separation of valuable metals from various coarse-grained metal-based scraps.
10.1016-j.jece.2025.117960	14	strength; properties; conductivity; electrical; mechanical; cu-; grain; mpa; electrical conductivity; aging; precipitation; phase; mechanical properties; tensile; phases	High-strength low-alloy (HSLA) steels, particularly HSLA-65, are widely used in marine applications due to their superior mechanical properties and excellent atmospheric corrosion resistance. However, their susceptibility to microbiologically influenced corrosion (MIC) remains a critical concern. In this study, copper (Cu) was alloyed with HSLA-65 steel and subjected to a controlled heat treatment to boost its antibacterial properties and enhance its resistance to MIC. Comprehensive microstructural analysis was conducted using optical microscopy (OM), transmission electron microscopy (TEM), and scanning electron microscopy (SEM), revealing a refined matrix structure and well-dispersed Cu precipitates. In electrochemical corrosion measurements, the aged Cu-HSLA-65 steel exhibited a significantly lower corrosion current density (3.04 mu A/cm2) and more positive corrosion potential (-546 mV) and pitting potential (-349 mV) compared to as-rolled HSLA-65 (8.62 mu A/cm2, -601 mV) and as-rolled Cu-HSLA-65 (5.84 mu A/cm2, -566 mV) steels. These results demonstrate the enhanced resistance of aged Cu-HSLA-65 steel against MIC by Pseudomonas aeruginosa (P. aeruginosa). Antibacterial study exhibited a high antibacterial rate for the aged Cu-HSLA-65 steel. In addition, the weight loss of aged Cu-HSLA-65 steel (0.0021 g/ cm2) measured after 14 days of immersion was much lower compared to that of the as-rolled HSLA-65 (0.007 g/ cm2) and as-rolled Cu-HSLA-65 (0.0045 g/cm2) steels, which further supported the material's sustained antimicrobial and anticorrosive performance. This work highlights the potential of Cu-alloyed HSLA-65 steel as a multifunctional material for marine applications, offering a promising solution to simultaneously mitigate MIC and improve structural durability in biologically aggressive environments.
10.1016-j.jelechem.2003.08.028	2	corrosion; surface; film; electrochemical; films; spectroscopy; layer; current; solution; potential; resistance; composition; x-ray; ions; showed	The electrodeposition of copper-zinc on to AISI 1010 steel from an alkaline non-cyanide solution containing sorbitol was investigated, with various proportions of the metal ions in the bath . Voltammetric curves indicated that the complexation of copper ion by sorbitol is beneficial, since the copper complex reduction potential is close to that of the zincate ion, implying that code-position of copper and zinc should occur. EDS analysis showed that varying the ratio of copper to zinc ions in the plating bath affects the proportion of metals in the deposits, leading to golden or greyish bright films, even in the high-hydrogen-evolution potential region, indicating that sorbitate anions prevent the deposits becoming darker in this region. The narrow variation in film colour at various deposition potentials and charge densities showed that rigorous control of the alkaline-sorbitol plating bath and deposition conditions is not necessary. SEM analysis showed that the films were without stress and the substrate was fully covered. X-ray spectra suggested that a mixture of Cu8O and CuZn2 alloy was deposited at -1.14 V in all the baths studied while Cu0.61Zn0.39 (Cu-70 bath), Cu5Zn8 (Cu-50 bath) and CuZn5(Cu-30 bath) films were deposited at both -1.45 and -1.60 V.
10.1016-j.jelechem.2006.07.009	2	corrosion; surface; film; electrochemical; films; spectroscopy; layer; current; solution; potential; resistance; composition; x-ray; ions; showed	Electrodeposition of Cu-Co-Ni coatings was performed from slightly acidic citrate-sulphate solutions. Bath composition and deposition potentials were varied in order to prepare copper-rich ternary coatings with different metal percentages. Low copper (11) and high nickel (11) concentrations were necessary to attain uniform non-dendritic electrodeposits with Co + Ni percentages between 10 and 30 wt%. Low magnetoresistive values were detected for as-deposited samples containing Co + Ni percentages around 25 wt%, although X-ray diffractograms showed miscibility of the three metals. The annealing of the samples at different temperatures led to granular coatings with the magnetoresistive values increase, as a consequence of the ferromagnetic metals segregation from within the non-magnetic matrix. Magnetic Force Microscopy (MFM) technique made possible to detect changes on the magnetic response between as-deposited and annealed samples.
10.1016-j.jelechem.2010.06.015	2	corrosion; surface; film; electrochemical; films; spectroscopy; layer; current; solution; potential; resistance; composition; x-ray; ions; showed	RDE voltammetry, XPS and XRD techniques were applied to investigate the codeposition of copper and tin from acid gluconate solutions. Voltammograms contain two plateaus of limiting current of diffusive nature which obeys Levich equation. Underpotential deposition of tin occurs at potentials 0.3 V higher than the equilibrium potential of Sn vertical bar Sn(II) electrode. Cu-Sn deposits contain carbon and oxygen that prevail at the surface and are found in the deeper layers of coatings. Chemosorption of gluconic acid with its partial destruction is supposed to take place. Bright Cu-Sn coatings are obtained when the quantity of inclusions is sufficiently high . Cu-Sn coatings obtained in the UPD area consist of alpha phase or solid solution of tin in copper and a small amount of pure copper. The beta-CuSn and delta-CuSn phases as well as a small amount of eta phase were detected at -0.31 V. At a more negative potential (-0.4 V) Cu-Sn coatings contain the pure Sn phase, eta phase and a small amount of beta-CuSn.
10.1016-j.jelechem.2015.06.003	2	corrosion; surface; film; electrochemical; films; spectroscopy; layer; current; solution; potential; resistance; composition; x-ray; ions; showed	D Cu-Zn coatings were obtained from cyanide-free electrolytes containing CuSO4 center dot 5H(2)O, ZnSO4. 7H(2)O, Triethanolamine (TEA) and NaOH with different cation concentrations. Electrochemical analyses were performed using cyclic voltammetry and potentiostatic polarization in order to analyze the effect of TEA as a complexing agent of Cu2+ and Zn2+ ions and its influence on the composition of the electrodeposited films. It was observed that TEA diminishes cathodic overpotential for the reduction of Zn2+ ions and increases cathodic overpotential for the reduction of Cu2+ ions. As a consequence, the simultaneous electrodeposition of Zn2+ and Cu2+ ions was facilitated and a brass (Cu-Zn alloy) coating was obtained from non-cyanide solutions. The composition and appearance of the Cu-Zn film can be modified by optimization of the cathodic current density and the concentration of TEA, Cu and Zn in the electrolyte. The ray-X results show a Cu-Zn coating with a content of Zn > 25% from a non-cyanide electrolyte as an alloy of alpha-CuZn. From the results of this work, a promissory and environmentally friendly alternative to the electroplating bath can be developed, from which a brass alloy can be electrodeposited using a non -cyanide electrolyte.
10.1016-j.jelechem.2015.12.036	2	corrosion; surface; film; electrochemical; films; spectroscopy; layer; current; solution; potential; resistance; composition; x-ray; ions; showed	The electrodeposition of Cu-Sn-Zn ternary alloys on to AISI 1010 steel from an acid bath, pH 4.99, containing trisodium nitrilotriacetic (NTA) was investigated, with different proportions of the metal ions in the baths. The Cu-Sn-Zn voltammetric profile showed four cathodic regions, irrespective of bath composition. The first three regions were associated with the reduction of the Cu-NTA and Sn-NTA complexes, and in the last region with Cu-NTA, Sn-NTA and Zn-NTA complexes reduction, attributed through of the analysis of the voltammetric curves together with the energy-dispersive X-ray spectroscopy (EDS) results. EDS analysis showed that only in cathodic region c(4) occurred the transition from Cu-Sn binary alloy to Cu-Sn-Zn ternary alloy, regardless of bath composition. In addition, Cu-Sn-Zn co-deposition, at E-d 1.60 V (cathodic region c(4)), was normal regardless of bath composition. Analysis of the photomicrographs of Cu-Sn-Zn electrodeposits obtained at electrodeposition potential (E-d) -1.60 V, with electrodeposition charge density (q(d)) of 3.0Ccm(-2), from 0.20Cu(2+)/0.050Sn(2+)/0.050Zn(2+) bath presented the highest grain size (0.77 mu m) and from 0.15Cu(2+)/0.075Sn(2+)/0.075Zn(2+) bath presented smaller grain size (0.27 mu m), all formed by irregular crystallites. Adhesion test showed that the Cu-Sn-Zn electrodeposit obtained at E-d 1.60 V, with q(d) 3.0Ccm(-2), from 0.10Cu(2+)/0.10Sn(2+)/0.10Zn(2+) bath presented a good adherence to the 1010 steel substrate, being classified as Gr(2). Laser scanning confocal microscopy (LSCM) showed that roughness increased from 1.48 mu m to 2.98 pm when Cu2+ ions concentration in the electrodeposition baths decreased. X-ray diffraction pattern indicated that the Cu-Sn-Zn electrodeposits produced at E-d-1.60 V with qd 3.0Ccm(-2), depending on bath composition, presented structure crystalline with a mixture of Sn, SnO, CuZn, Cu5Zn8, eta-Cu6Sn5 and Cu20Sn6 phases, indicating the formation of Cu-Sn-Zn ternary alloy. (C) 2015 Published by Elsevier B.V.
10.1016-j.jelechem.2018.07.023	2	corrosion; surface; film; electrochemical; films; spectroscopy; layer; current; solution; potential; resistance; composition; x-ray; ions; showed	This study characterizes the Cu-Sn-Zn electrodeposits produced potentiostatically from baths containing different concentrations of Cu2+, Sn2+ and Zn2+ ions and 0.60 M trisodium nitrilotriacetic (NTA) at pH 4.99 (higher stability). Ternary electrodeposits were produced onto AISI 1010 steel substrate at electrodeposition potential of -1.60 V with electrodeposition charge density of 3.0 Ccm(-2). Chemical composition of electrodeposits varied significantly, presenting higher Cu content (at%) than that of other elements. Furthermore, it was verified that the high concentration of Sn2+ ions in the baths hindered the reduction of Zn2+ ions, leading to Zn-poor electrodeposits. Microstructure was generally composed of irregular crystallites and clusters of crystallites or dendrites dispersed on the surface, depending on chemical composition. X-ray diffraction showed formation of the ternary alloy by mixture of the Cu5Zn8, eta-Cu6Sn5 and Sn pure phases. In addition, electrodeposits with lower Cu content (at%) also showed the SnO phase. Surface topography of the electrodeposits presented a rough aspect, with arithmetic roughness varying from 1.83 to 3.90 mu m for electrodeposits with lower and higher Sn content (at%), respectively. Adhesion tests indicated that the highest and lowest adherence percentages to the steel substrate were observed for the electrodeposits with the largest Zn and Sn contents (at%), respectively.
10.1016-j.jelechem.2019.113310	2	corrosion; surface; film; electrochemical; films; spectroscopy; layer; current; solution; potential; resistance; composition; x-ray; ions; showed	Over the last decade, nanoporous metals have attracted a growing attention due to the combination of structural and functional properties, such as their very high surface to volume ratio and mechanical rigidity. A recent and versatile process producing nanoporous metals is the dealloying of an initial alloy, i.e. the selective dissolution of the more reactive element of the alloy. In this work, we report on a method of CuZn alloy formation, without the use of furnaces or expensive techniques, and its subsequent chemical dealloying leading to nanoporous copper. Co-electrodeposition of CuZn alloys on a copper substrate is performed using pyrophosphate as a complexing agent in presence of boric acid, copper sulfate and zinc sulfate. The electrochemical behavior of this system is characterized by cyclic voltammetry, showing that a copper-zinc alloy is formed at -1.5 V vs. SCE. Cauliflower-like Zn-rich gamma-brass and epsilon-brass coatings are obtained by co-electrodeposition. The thickness, the structure and the composition of the electrodeposited alloy can be tuned by varying the electrodeposition conditions. Thicker and rougher coatings with a higher zinc content are formed at more cathodic conditions. The electrodeposited CuZn coatings were chemically dealloyed, and a two-step dealloying protocol leads to open framework nanoporous copper templates, which are a material of interest for energy storage, biosensors, and catalysis applications. (C) 2019 Published by Elsevier B.V.
10.1016-j.jelechem.2021.115688	2	corrosion; surface; film; electrochemical; films; spectroscopy; layer; current; solution; potential; resistance; composition; x-ray; ions; showed	The corrosion behaviour study of Cu-Pb alloy in simulated archaeological soil environment were investigated using electrochemical accelerated corrosion, Field emission scanning electron microscopy/energy dispersive spectroscopy, laser scanning confocal microscope, X-ray photoelectron spectroscopy and electrochemical methods. It is crucial that the corrosion resistance of the Cu-Pb alloy was found to alter with the Pb content in the alloy. The results demonstrated that Cu-13.28Pb alloy exhibited the best corrosion resistance with the smallest corrosion current density and the lowest anodic dissolution rate. The corrosion products are mainly composed of matrix metal oxides and metal-insoluble inert compounds. The correlation between Pb content and corrosion behaviour and the corresponding corrosion mechanism were clarified.
10.1016-j.jelechem.2022.116636	2	corrosion; surface; film; electrochemical; films; spectroscopy; layer; current; solution; potential; resistance; composition; x-ray; ions; showed	Nantokite (CuCl) layer induces severe corrosion of bronze by its active reactivity to copper alloy. To further understand its corrosion mechanism, this paper investigated the electrochemical evolution process of the Cu-S n-Pb ternary alloy covered with a CuCl layer by continuous electrochemical impedance spectroscopy (EIS) monitoring. And the EIS changing mechanism induced by dynamic Cl- circulation and the transformation of the CuCl were also discussed. The results showed that two extreme impedance value points, the 3rd and 7th hours, were observed during the evolution process of the CuCl layer within 48 h . The decrease of the impedance value at 0 similar to 3 h was mainly affected by the reaction of CuCl hydrolysis forming a Cu2O film, while the increase of impedance value at 3 similar to 7 h was affected by the reaction of copper attacked by chloride ion. After 7 h, the impedance value of the Cu-Sn-Pb alloys continued to increase due to the formation of a dense cuprous oxide layer and chloride ions migrating into solution.
10.1016-j.jelechem.2023.118013	2	corrosion; surface; film; electrochemical; films; spectroscopy; layer; current; solution; potential; resistance; composition; x-ray; ions; showed	Corrosion of Q235 carbon steel and the BFe30-1-1 copper-nickel alloy was studied in seawater with electrochemical methods and surface characterization. The open circuit potential (OCP) for the copper-nickel alloy and carbon steel were -225 mV and -700 mV, respectively. A Gel visualization test showed that Turnbull's blue was precipitated on the surface of Q235, which indicated accelerated corrosion of the Q235 anode after coupling. The increased Kelvin potential determined for the Q235 surface with a Scanning Kelvin Probe test indicated that the Q235 surface generated electrons and transferred them to the BFe30-1-1 surface, which resulted in the protection of BFe30-1-1. These tests showed that the Q235 anode underwent corrosion, and the BFe30-1-1 cathode was protected after coupling in seawater. Surface analyses showed that Q235 corroded faster over time due to electric coupling, while BFe30-1-1 corrosion was inhibited by a stable passivation film. Analysis of the physical phase showed that the corrosion products of Q235 were beta-FeOOH, alpha-FeOOH and Fe3O4, and the BFe30-1-1 corrosion products were Cu2O and Cu2Cl(OH)(3). The electrochemical and numerical results were consistent, indicating an accurate prediction of the galvanic corrosion process.
10.1016-j.jenvman.2017.05.028	-1		This study investigates, verifies and determines the optimal parameters for the selective thermal transformation of problematic electronic waste (e-waste) to produce value-added copper-tin (Cu-Sn) based alloys; thereby demonstrating a novel new pathway for the cost-effective recovery of resources from one of the world's fastest growing and most challenging waste streams. Using outdated computer printed circuit boards (PCBs), a ubiquitous component of e-waste, we investigated transformations across a range of temperatures and time frames. Results indicate a two-step heat treatment process, using a low temperature step followed by a high temperature step, can be used to produce and separate off, first, a lead (Pb) based alloy and, subsequently, a Cu-Sn based alloy. We also found a single-step heat treatment process at a moderate temperature of 900 degrees C can be used to directly transform old PCBs to produce a Cu-Sn based alloy, while capturing the Pb and antimony (Sb) as alloying elements to prevent the emission of these low melting point elements. These results demonstrate old computer PCBs, large volumes of which are already within global waste stockpiles, can be considered a potential source of value-added metal alloys, opening up a new opportunity for utilizing e-waste to produce metal alloys in local micro factories.
10.1016-j.jeurceramsoc.2021.06.002	-1		The wetting of ZrB2 ceramic by molten pure Cu, Cu-(20, 30, 40, 50 at%)Ti alloys were performed by the sessile drop method under vacuum of similar to 4 x 10(-4) Pa in the 1030-1070 degrees C temperature range. The wetting and interfacial behaviors of Cu-Ti/ZrB2 systems were analyzed and discussed. Furthermore, the work of adhesion and electronic properties of the Cu(1 1 1)/ZrB2 (0 0 0 1) and Ti(0 0 0 1)/ZrB2 (0 0 0 1) atomic interfaces were quantitatively evaluated by first-principles method. The wettability is significantly improved with the Ti concentration or wetting temperature increasing as a result of the formation of (Ti) solid solution at interface. The calculated results show that the B-terminated ZrB2 (0 0 0 1) surface is preferable to bond with Ti(0 0 0 1) surface, and the electronic structure reveals that the dominant interfacial bonding is the Ti-B ionic bond for the Ti/B-terminated ZrB2 interface.
10.1016-j.jeurceramsoc.2024.01.025	-1		Wetting of Al2O3 by molten Cu-xTi alloys with wide composition range was deeply studied. The results show that the precipitation of TiO at the interface is depended on the Ti concentration in the alloys as well as the oxygen partial pressure in the atmosphere. When Ti concentration is lower than the critical Ti concentration, the wettability of the system is mainly determined by the precipitated TiO and the adsorption of Ti-O clusters at the interface; conversely, it is mainly determined by the adsorption of Ti-O clusters on the surface of alumina. For the spreading dynamics of: Cu-Ti alloys on the sapphire surface, the existence of two stages were observed: firstly, an initial fast spreading stage, which is mainly limited by the reaction rate of TiO precipitation; followed by a later slow spreading stage, which is mainly limited by the precipitation reaction of Al2O, and exhibits a stepwise spreading characteristic.
10.1016-j.jics.2025.102159	-1		The electrodeposition of Cu-Sn-Zn ternary alloys has attracted interest as a safer alternative to conventional toxic coatings. However, the use of a formate-based electrolyte composed of CuCl2, SnCl2, and ZnCl2 and the effect of plating temperature on coating performance when using a carbon substrate remain underexplored. In this study, the effects of different plating temperatures on the cathodic current efficiency (CCE), deposition rate, coating thickness, microhardness, corrosion resistance, morphology, elemental composition, and phase formation of Cu-Sn-Zn alloys electrodeposited onto a carbon substrate were investigated. The optimal temperature of 50 degrees C provided the highest CCE of 78.82 %, a deposition rate of 48.29 mu m/h, a coating thickness of 10.71 mu m, microhardness of 455.95 HV, and a low corrosion rate of 0.0679 mm/year. Scanning Electron Microscopy (SEM) revealed irregular shapes with uneven distribution, yet fewer fine voids and pinholes were observed, alongside a balanced composition of 55.67 wt% Cu, 29.31 wt% Sn, and 15.80 wt% Zn using Energy-Dispersive X-ray spectroscopy (EDX). X-ray diffraction (XRD) showed a high texture coefficient, indicating a stable orientation and uniform crystallite growth . These findings demonstrated that the plating temperature significantly influenced the coating quality and corrosion resistance, highlighting the feasibility of using a formate-based electrolyte for sustainable alloy deposition. Future studies should investigate the long-term durability and industrial scalability of Cu-Sn-Zn ternary alloy coatings when applied to jewelry substrates.
10.1016-j.jiec.2021.05.009	17	wear; composites; coating; friction; composite; coatings; surface; tribological; properties; wear resistance; resistance; powder; sliding; matrix; wear rate	Herein, copper perrhenate (Cu(ReO4)(2)) was synthesized using a micro-emulsion method and adhered to graphene (Gr) using an ultrasonic process. Then, the as-prepared Cu(ReO4)(2)/Gr composite was added into the synthetic oil as a lubricant additive with the help of ionic liquid to achieve enhanced dispersion stability within the base oil. The tribological performances of the Cu(ReO4)(2)/Gr additive were investigated using four-ball tests and the ball-on-disk reciprocating configuration under various temperatures. The potential lubrication mechanisms of the Cu(ReO4)(2)/Gr additive were performed using a series of characterization methods including XRD, Raman, SEM-EDS, TEM, DSC/TG, and XPS. The results of four-ball tests at room temperature indicated that the Cu(ReO4)(2)/Gr additive could substantially improve the tribological performances of the base oil. The smallest coefficient of friction (COF) and wear scar diameter (WSD) values were 0.068 and 495 mm, respectively, when 0.05 wt% of Cu(ReO4)(2)/Gr was added. Additionally, the graphene accelerated friction-induced heat transfer, which led to decreased friction and wear. The results of reciprocating friction experiments at elevated temperatures revealed that the Cu(ReO4)(2)/Gr additive had excellent friction-reduction properties when the temperature was high . This could be attributed to the generation of a protective layer containing tribo-oxides from the alloy, some residual carbides and copper perrhenate induced by friction heat and stress. This protective layer was uniformly and stably covered on the worn surface, which could effectively alleviate direct contact between the rubbing pair.
10.1016-j.jksus.2017.12.002	16	wear; composite; composites; powders; milling; particles; powder; wt; sliding; friction; hardness; matrix; mechanical; surface; properties	This research investigated the effect of tungsten content on the structure, physical and mechanical properties of silicon bronze (Cu-3 wt%Si). Tungsten was added in concentrations of 0.1, 0.3, 0.5, 0.8, 1 and 1.5 wt%. The samples were produced using permanent die casting technique, machined and stored for the structural analysis, physical and mechanical tests. The microstructural analysis of the control sample (Cu-3 wt%Si) revealed the presence of dendrite of intermetallic compounds which could be primary silicon and copper silicide (Cu3Si) phases while the alloy doped with tungsten consisted of fine grains of intermetallic compounds evenly dispersed in the copper matrix. The mechanical tests results showed that addition of tungsten to silicon bronze significantly increased the percentage elongation, ultimate tensile strength, hardness and electrical conductivity of the alloy by 174.5%, 741.2%, 98.9% and 14.9% respectively. Maximum percentage elongation, electrical conductivity, ultimate tensile strength and hardness of 25.8%, 61.25% IACS, 286 MPa and 358 BHN respectively were obtained. (C) 2017 The Author. Production and hosting by Elsevier B.V. on behalf of King Saud University.
10.1016-j.jksus.2019.01.001	-1		The structural sensitive properties of Cu-3Si-xMn ternary alloys with six different manganese contents were properly studied. The refining effect of manganese addition on the cored dendritic grains of air-cooled cast Cu-3Si alloy was investigated. The microstructure of the Cu-3Si-xMn alloys was also analyzed by using an Optical Microscope (OM) and Carl ZEISS Scanning Electron Microscope (SEM). The elemental composition analysis was properly performed using Energy Dispersive X-ray Spectroscopy (EDS). The results showed that manganese addition refined the cored dendritic grains of Cu-3Si alloy. The ductility, tensile strength and Brinell hardness of Cu-3Si alloy were increased by 78.7%, 1,011.8%, and 106.1% respectively. The fine grains induced the improvements of the mechanical properties. Cu-3Si-xMn alloy showed ductility of 16.8%, a tensile strength of 378 MPa and hardness of 371 BHN. Manganese addition reduced the electrical conductivity of Cu-3Si alloy from 46.3% International Annealed Copper Standard (IACS) to 38.6 %IACS. (C) 2019 The Authors. Production and hosting by Elsevier B.V. on behalf of King Saud University.
10.1016-j.jlp.2023.105065	-1		The microscopic characteristics of melting trace caused by copper wire fault are an important basis for the physical evidence identification of electrical fires. Metallography is an important method in electrical fire research, and computer-aided quantitative analysis on metallographic structure is common in materials aspect. In this study, the metallographic structure and phase composition characteristics of melting trace caused by overcurrent fault were explored with the aid of a metallographic microscope and an X-ray diffractometer (XRD). The results show that the grains are mainly slender dendritic and columnar crystals when the current is 128 A, while they are coarse dendritic and cellular crystals when the current is greater than 192 A; the average grain diameter of melting trace of copper wire grows with the increase in current. The main phases of melting trace caused by overcurrent fault of copper wire are alpha-Cu base and Cu2O, and the new phases Cu4Si and Cu2Mg are formed when the current is higher than 160 A. In addition, the solidification process of metallographic structure of copper wire under different currents was simulated by the Procast software. It is found that the simulation results are basically in agreement with the experimental data, which suggests that this model can effectively predict the microstructure characteristics of melting trace of copper wire under different currents. The research results can provide a sound basis for the physical evidence identification of electrical fire and improve the ac-curacy and scientificity of electrical fire investigation.
10.1016-j.jma.2020.02.015	-1		Duplex nanoporous Cu was successfully fabricated by dealloying a dual-phase Mg-Cu precursor alloy consisting of intermetallic Mg2Cu and MgCu2. The duplex nanoporous Cu with embedded nanoporous struts exhibited highly enhanced strength compared to the typical monolithic nanoporous Cu under both compressive and flexural test conditions at room temperature; the duplex np-Cu sample exhibited a 12 times higher compressive strength and a 40 times greater flexural strength than the monolithic np-Cu sample. Factors responsible for the strength enhancement in the duplex nanoporous Cu are discussed. (c) 2020 Published by Elsevier B.V. on behalf of Chongqing University.
10.1016-j.jmapro.2017.09.009	-1		Incremental Sheet Forming (ISF) is a novel sheet forming process. Being characterized by severe deformation, the process is likely to induce high residual stresses in the sheet metal components. These stresses in turn can affect the lifetime and integrity of the components. The present study, therefore, systematically analyzes the state of in-plane residual stresses as the function of technological parameters. The Cu/Steel bonded laminates are deformed and the hole drill tests are performed to determine the residual stresses in the laminates. The results show that the in-plane principal residual stresses are compressive in nature. Further, their magnitude decreases from one end to the other end of thickness section (i.e., from contact surface to non-contact surface). The in-plane maximum residual shear stress is found to be a way smaller than either of the in-plane principal residual stresses. The Analysis of Variance is performed to identify the role of technological parameters on the state of residual stresses. It is found that the tool diameter and wall angle are the most influential parameters while the rotation is the least influential parameter in this regard. The detailed analysis of response surfaces reveal that the combination of low diameter, high angle, middle step size, medium rotation, high feed rate and rolled condition of material (i.e., no annealing) promote the development of higher residual stresses. The relationship between the equivalent residual stress and the post-ISF yield stress shows that the former quantity is generally smaller than the latter one. Finally, empirical models are proposed to predict the state of in-plane principal residual stresses in the Cu/Steel components produced through the ISF process. (C) 2017 Published by Elsevier Ltd on behalf of The Society of Manufacturing Engineers.
10.1016-j.jmapro.2018.07.013	-1		Currently, the forming processes employed on formation of laminated composite metal sheets belong to quasistatic loading either in macroscale or microscale. Innovative forming processes are requested to meet the challenges in manufacturing of micro components produced by new materials. A new process that employing microscale laser flexible dynamic forming (MLFDF) on formation of laminated composite metal sheets was adopted in this paper. The feasibility of this new process was verified firstly. The research results showed that, the forming depth of Cu/Ni laminated composite metal sheets under MLFDF increased with laser energy increasing, number of laser pulse increasing and thickness of soft punch decreasing. Surface roughening happened in formed parts and the roughness increased with laser energy increasing. Deformation of Cu/Ni laminated composite metal sheets was dominant by external layer. Unlike conventional forming processes, it was found stacking sequence didn't have considerable effect on forming behavior of Cu/Ni laminated composite metal sheets under MLFDF. Another advantage of MLFDF was discovered that Cu/Ni laminated composite metal sheets were formed without any delamination till fracture under this forming process. The experiment revealed that MLFDF could be a promising alternative of conventional microscale forming processes for formation of laminated composite metal sheets.
10.1016-j.jmapro.2021.05.018	-1		In this research, the combined effect of pre-rolling and submerged friction stir processing (SFSP) on the microstructure, hardness, and tensile behavior of commercially pure copper were evaluated. Several voids and cavities were observed in the stirred zone of 0 %-400, 60 %-400, 60 %-600, and 0 %-800 samples, and the defect-free copper could be achieved under a narrow process window. The microstructures revealed that a significant decrement in grain size occurred in the stirred zone of the SFSP-processed coppers due to the occurrence of dynamic recrystallization (DRX) and water cooling conditions. The pre-rolling led to decreasing the grain size after the SFSP owing to providing more nucleation sites for recrystallization. In the 60 %-800 sample, despite the increase in heat-input by increasing the rotational speed, due to the pre-strain, the average hardness was about 5 HV higher than the 0 %-600 sample (92.2 HV vs. 87.1 HV). In the case of the 0% sample, by conducting the SFSP, the yield and ultimate tensile strengths (YS and UTS) increased to 215 and 277 MPa, respectively, due to the lower grain size of the 0 %-600 sample as compared to the 0% sample (4.5 mu m vs 17.9 mu m). On the other hand, in the 60 %-800 sample, the YS and UTS reduced to 307 MPa as compared to the 60 % sample owing to the transition of the strengthening mechanism from strain hardening to grain refinement. The fractured surfaces of all samples exhibited a ductile manner. However, after the SFSP, the size and depth of dimples were reduced due to the finer grain size.
10.1016-j.jmapro.2022.03.041	-1		Explosive welding of high-strength precipitate-hardened alloys in large thickness was very challenging but was increasingly desired with the continuous development of high-end equipment. An innovative strategy, which was previously proposed to achieve joining at the solid-solutioned state at first and improve the composite properties by later thermal treatment, was validated here using a Cu-Ni-Si-Cr alloy as a model material. Under the same welding condition, the composite welded at the solid-solutioned state exhibited a larger wave amplitude than that joined at the peak-aged state, an evident proof of better weldability. Further numerical analysis indicated that the enhanced weldability of the solid-solutioned alloy was closely related with its lower deformation resistance. The composite joined at the solid-solutioned state achieved a slightly lower peak hardness and yield strength than the counterpart for the thermally weakened deformation hardening effects and the more interfacial defects, while the electrical conductivity of them was comparable.
10.1016-j.jmapro.2022.06.055	-1		The copper alloy -stainless steel (SS316L) bimetallic combination using additive manufacturing (AM) was suc-cessfully demonstrated by building the stainless steel on the copper alloy using the selective laser melting pro-cess. The tensile coupon having an interface at the centre of gauge length failed on the copper alloy side away from the interface region, motivated to investigate the interface bonding mechanism and correlation between microstructural and mechanical properties. Microstructural characterization of the initial few deposited layers showed the circular melt pool features in which inter-presence of copper and steel-rich regions were observed, owing to the intensification of the Marangoni convection in the melt pool during the selective laser melting. Analysis of the interface region by Transmission Electron Microscopy (TEM) reveals the formation of nano-sized Fe-rich particles inside the copper-rich matrix. The diffusion of Fe, Cr, and Ni elements from the steel to the copper side, confirmed by energy dispersive spectroscopy (EDS), led to the solid solution strengthening of copper near the interface which was also reflected in the micro-hardness profile. The bi-metallic interface manifested higher strength than copper alloy due to good interface bonding, possibly by the presence of an interconnected network of copper and steel-rich regions at different length scales.
10.1016-j.jmapro.2022.08.022	-1		Owing to their excellent mechanical properties, copper-steel bimetallic sheets are considered one of the best choices for preparing the plasma-facing components of the International Thermo-nuclear Experimental Reactor (ITER). However, due to the solid immiscibility between copper (Cu) and steel (St), it is hard to obtain desired interfacial bonding when using conventional fabrication processes, like rolling and explosive welding. In this work, Cu-St bimetallic sheets were fabricated by friction stir additive manufacturing (FSAM). Microstructural studies show that the wave-like interface with desirable joining was created between copper and steel. Me-chanical tests present that the tensile strength and shear strengths are 435 MPa and 345 MPa, respectively. Such properties are remarkably better than that of other methods. Finally, the microstructure evolution and the relationship between microstructure and mechanical properties were discussed. These findings provide an effective way to regulate the interface engineering of bimetallic sheets.
10.1016-j.jmapro.2022.09.037	-1		In this paper, the bypass-current plasma arc welding (BC-PAW) based on PAW was employed to fabricate copper -nickel (Cu-Ni) gradient thin-walled structures. The effect of forming accuracy and compositional homogeneity of the bypass current Cu-Ni structure was first verified by controlled experiments. The effect of Ni content on the microstructure and mechanical properties of Cu-Ni gradient structures fabricated using bypass current was then investigated, with a focus on grain orientation and texture analysis of the three intermediate Cu-Ni mixed gradient layers. The results showed that the use of bypass current in the additive manufacturing of Cu-Ni gradient structures can improve the forming accuracy and effectively eliminate lateral composition deviations within the gradient layers. In the Cu-Ni mixed gradient layers, the average grain size of the gradient layers decreased with increasing nickel content, and unusually large secondary grains appeared in different gradient layers. Due to the different Ni content, different degrees of amplitude modulation decomposition occurred in different gradient layers, resulting in changes of grain orientation and texture composition. Under the combined effects of solid solution strengthening, fine grain strengthening and amplitude modulation decomposition, the microhardness and tensile strength increased with increasing nickel content and then decreased, reaching a maximum near the side of the gradient composition biased toward nickel. The fracture analysis showed a transition from ductility to quasi-fracture.
10.1016-j.jmapro.2024.03.002	-1		Cu-Cr-Zr alloys are widely used as medium-strength and high-conductivity copper alloys in aerospace, transportation and electronic information fields. The application of additive manufacturing technology is expected to realize the preparation of Cu-Cr-Zr alloy parts with complex structure and superior property. However, the commonly used laser additive manufacturing technology is not applicable to the preparation of copper alloys due to its intrinsic high reflection to laser. In this study, we adopted two technologies, i.e., electron beam additive manufacturing (EBAM) and laser-metal inert gas hybrid welding (laser-MIG), for the preparation of Cu-Cr-Zr alloys. Finite element simulation was employed to simulate the temperature field and residual stress field of the material during solidification. The microstructure, relative density, microhardness, tensile properties and electrical conductivity of the as-fabricated samples were characterized. The results showed that samples with better moldability were obtained by both methods at a line energy density of 600 J/mm. In the top area, both methods exhibit medium-sized equiaxed grains with more precipitated phases, showing the best comprehensive properties. The EBAM method demonstrates superior formability, better relative density and electrical conductivity due to more stable temperature field changes. On the other hand, the laser-MIG method obtains finer grains and higher mechanical properties because of a faster cooling rate, but leads to a decrease in relative density and electrical conductivity. This study presents new experimental data for Cu-Cr-Zr alloys prepared by EBAM and laser-MIG methods, contributing to extend the application of additive manufacturing in the preparation of Cu alloys.
10.1016-j.jmapro.2024.09.069	-1		Copper and its alloys play a crucial role in various engineering applications due to their excellent conductive properties. However, their poor laser absorptivity and high conductivity make them a complex material to work with using laser additive manufacturing processes, hindering the ease of fabrication of precise and complex geometries. To overcome this challenge, graphene-reinforced copper powders were employed to enhance laser absorptivity. With graphene addition, there was a substantial increase in the laser absorptivity. The addition of graphene improved laser absorptivity from 15 % for pure copper to similar to 60 % in Gr-Cu composites. However, the flowability deteriorated at higher compositions, which could result from increased specific surface area due to graphene agglomeration and its nanoscale surface. The influence of graphene on the ease of fabrication employing laser powder-directed energy deposition was evaluated with a single-track and bulk deposition. A single-track study revealed that pure copper tracks were inconsistent and exhibited poor bonding due to their poor laser absorptivity. Meanwhile, graphene-copper composite tracks displayed stable melt pools and uniform tracks, which could result from enhanced absorptivity. Geometrically sound and defect-free Gr-Cu tracks were deposited using 750 W laser power with composite powders, while pure copper tracks at 950 W laser power deposition yielded defective tracks. However, a graphene percentage above 0.1 % resulted in the formation of keyhole porosity due to a significant enhancement in laser absorption (similar to 60 %). A similar observation was made for bulk deposition, i.e., defect-free deposition for Gr-Cu composites <= 0.1 % graphene and keyhole porosities in the deposition of 0.25Gr-Cu and 0.8Gr-Cu.
10.1016-j.jmapro.2025.01.069	-1		Laser additive manufacturing (LAM) technology is a promising technology for the fabrication of Cu-Mo immiscible alloys with good electrical and thermal conductivity. However, the high reflectivity of Cu on widely applied near-infrared laser (wavelength: 1000-1100 nm) prevents the effective absorption of laser energy and even damages LAM machines, hindering the wide application of LAM in the preparation of Cu-Mo immiscible alloys. In this study, a well-designed ball milling method is employed to modify surface of Cu powder using fine Mo particles as the modifier to improve their laser absorptance. The effect of different ball milling conditions including ball milling time, rotation speeds, dispersion of Mo particles and their addition content on the modification effectiveness of Mo on Cu and the laser absorptance is investigated in detail. The results show that the Mo-modified Cu powder consists of coarse spherical Cu particles evenly embedded with fine Mo particles. When the ball milling with a ball-to-powder ratio of 5:1 is performed for 1 h at 200 rpm, the light absorption at 1084 nm of the Mo-modified Cu powder with the surface modifier content of 10 wt% reaches 60.3 %, significantly higher than 16.8 % of raw Cu powder. Besides, the morphology of Mo-modified Cu powder under the optimized condition remains spherical, which is still suitable for the later LAM processing. This work provides an important theoretical and technical support for the laser absorptance improvement of high-reflectivity metal powders.
10.1016-j.jmapro.2025.06.007	14	strength; properties; conductivity; electrical; mechanical; cu-; grain; mpa; electrical conductivity; aging; precipitation; phase; mechanical properties; tensile; phases	This study explores high-power laser powder bed fusion (LPBF) of Cu-Cr-Zr alloy, focusing on optimizing process parameters to achieve high relative density (RD) and low surface roughness (S-a). A Plackett-Burman design (PBD) identifies layer thickness, laser power, and scanning speed as the most significant parameters. A response surface method (RSM) with central composite design (CCD) further refines the process, yielding an optimized parameter set with an RD of 99.96 % and S-a of 13.1 mu m. After establishing the optimum process window, the process efficiency is examined by increasing layer thickness, demonstrating higher build rates while preserving high RD and acceptable S-a. The samples are evaluated for mechanical properties and microstructural evolution. Microhardness mapping reveals a uniform hardness distribution, with values ranging from 90 to 94 HV. Microstructural analysis shows the grain morphology varies with process parameters; thinner layers tend to produce bimodal distributions, whereas thicker layers promote more uniform grain structures. Crystallographic analysis indicates a strong <001> texture in samples processed at high volumetric energy density (VED), while subgrain analysis highlights significant fractions of low-angle grain boundaries, reflecting residual stresses and high dislocation density.
10.1016-j.jmapro.2025.06.080	14	strength; properties; conductivity; electrical; mechanical; cu-; grain; mpa; electrical conductivity; aging; precipitation; phase; mechanical properties; tensile; phases	Inter-layer deformation serves as an effective strategy to refine the micro-structure of wire arc-directed energy deposition (WA-DED), enabling the formation of periodic heterogeneous structures with alternating coarse grains (CG) and fine grains (FG) region. However, the mechanical behavior of such periodic micro-structures remains inadequately explored. This work provides a novel methodology for studying the deformation behavior of materials fabricated via IH hybrid WA-DED processes. The crystal plasticity finite element method (CPFEM) was first used in this study to investigate the evolution of mechanical properties of layered heterogeneous structures produced during the Inter-layer hammering (IH) WA-DED process under tensile simulation, establishing the relationship between microstructure and properties. The IH process yielded a Cube texture dominated microstructure, with CG displaying a marginally higher Schmid factor (0.478) than FG (0.465). Notably, CG region exhibited elevated geometric compatibility factors (m ') at grain boundaries compared to FG region, promoting preferential dislocation slip activation and enhanced strain accommodation in CG region. CPFEM results demonstrated that slip systems in CG region were initially activated during the early plastic deformation stage. As deformation progressed, the distinct strain accommodation capacities between CG and FG region induced transverse cracks along the FG/CG interfaces to the tensile direction. Combined analysis of Schmid factors and m ' revealed that slip systems were predominantly activated perpendicular to the tensile direction, driving the nucleation and propagation of ductile cracks along this orientation. The interplay between single-slip system activation and dislocation motion emerged as the dominant deformation mechanism in the IH specimen, resulting in complex stress-strain distributions. These findings highlight the critical role of heterogeneous microstructural features in governing deformation mechanisms and damage evolution in WA-DED processed alloys.
10.1016-j.jmatprotec.2003.09.001	-1		The theory of deposition of TiN by dc magnetron sputtering for wear protection of the surfaces is well known using different ferrous substrates. This theory apparently, is not so true for other non-ferrous materials. The present work shows the study of some characteristics of TiN deposition on a ternary copper alloy (Cu-3% Ti-1% Cr) with the purpose of modifying their superficial properties, and in this way allowing to enlarge the alternatives of use of this alloy. The wear, microhardness and adhesion of the films deposited have been studied under different conditions of applied current, Ar/N-2 flow ratio and bias voltage by means of dc planar magnetron sputtering. By this study we concluded that, unlike the case of steel, for increasing the wear resistance of the alloy it is advisable not to use bias voltage during TiN deposition. It is desirable to obtain an open columnar structure in order to increase the wear resistance and the critical load in scratch testing. (C) 2003 Published by Elsevier B.V.
10.1016-j.jmatprotec.2005.05.011	-1		The fabrication of the copper matrix composites strengthened with dispersal nanometer Al2O3 is investigated. The investigation result shows that aluminum in Cu-Al alloy powder can be oxidated by the action of oxidizer Cu2O to form nanometer Al2O3 in nitrogen atmosphere. the more appropriate temperature of internal oxidation is at 950 degrees C and the more appropriate time is for 0.5 h . Sintering is at 950 degrees C for an hour. The results show that the crystal structure of Al2O3 is alpha-Al2O3, beta-Al2O3 and gamma-Al2O3. The main forming phase is nanometer gamma-Al2O3 which size is about less than 12 nm. The nanometer gamma-Al2O3 grains about 35% are not only in crystalline grains of copper but also in crystal boundary of copper. alpha-Al2O3 and alpha-Al2O3 are all in crystal boundary of copper. As compared with the composite by a previous sintering, the tensile strength and yield strength of Al2O3/CU composite increase respectively from 394 and 150 to 615 and 420 MPa after plastic deformation. And Al2O3/CU composite is provided with fine thermal stability. It shows that the Al2O3/CU composite can be used as the heat-resistant, wear-resistant and electric parts, such as the electrodes resistance welding, the electricity brushes of motors and so on.
10.1016-j.jmatprotec.2006.03.156	-1		The good bearing materials can be made from the compacted mixture of aluminium and aluminium bronze chips without participation of metallurgical processes. The parameters to obtain a good bonding of aluminiurn and CuA18 aluminium bronze chips separated by a layer of oxide can be determined on the base of the new form of sintering criterion. Diffusion bonding process of aluminium and aluminium bronze chips leads to creation of the phases typical for Cu-Al equilibrium diagram. Because during the hot extrusion the diffusion bonding is very slow, after extrusion heat treatment must be applied.
10.1016-j.jmatprotec.2007.04.116	4	transformation; martensite; martensitic; phase; shape; beta; memory; shape memory; temperature; temperatures; martensitic transformation; gamma; transformation temperatures; effect; thermal	Morphologies and configurations of the self-accommodating martensites in Cu-11.92 wt%Al-3.78wt%Ni shape memory alloy were studied by means of scanning electron microscopy (SEM) and transmission electron microscopy (TEM). From microstructural observations, it is clearly observed that the self- accommodating martensites have typical plate group configuration. Each martensite plate group consists of four variants A, B, C, and D. Usually, variants A and C (or B and D) form characteristic spear morphology and variants A and D (or B and C) form fork morphology. Variants A and C are twin-related with respect to the ((1) over bar (2) over bar 1)(2H) mirror plane of the 2H martensite. Additionally, TEM observations reveal that two kinds of close-packed martensite structures, 2H (gamma(')(1)) and 18R (beta(')(1)) martensites, coexist in the quenched alloy. These structures occur by the localized formation of four variants of a plate group in a self-accommodating manner to minimize the total shape change.
10.1016-j.jmatprotec.2007.08.019	16	wear; composite; composites; powders; milling; particles; powder; wt; sliding; friction; hardness; matrix; mechanical; surface; properties	Copper matrix was reinforced with Al2O3 particles of different size and amount by internal oxidation and mechanical alloying accomplished using high-energy ball milling in air. The inert gas-atomised prealloyed copper powder containing 1 wt% Al as well as a mixture of electrolytic copper powder and 3 wt% commercial Al2O3 powder served as starting materials. Milling of Cu-1 wt% Al prealloyed powder promoted formation of fine dispersed particles (1.9 wt% Al2O3, approximately 100 nm in size) by internal oxidation. During milling of Cu-3 wt% Al2O3 powder mixture the uniform distribution of commercial Al2O3 particles has been obtained. Following milling, powders were treated in hydrogen at 400 degrees C for 1 h in order to eliminate copper oxides formed at the surface during milling. Compaction was executed by hot-pressing. Compacts processed from 5 to 20 h-milled powders were additionally subjected to high-temperature exposure at 800 degrees C in order to examine their thermal stability and electrical conductivity. Compacts of Cu-1 wt% Al prealloyed powders with finer Al2O3 particles and smaller grain size exhibited higher microhardness than compacts of Cu-3 wt% Al2O3 powder mixture. This indicates that nano-sized A1203 particles act as a stronger reinforcing parameter of the copper matrix than micro-sized commercial Al2O3 particles. Improved thermal stability of Cu-1 wt% Al compacts compared to Cu-3 wt% Al2O3 Compacts implies that nano-sized Al2O3 particles act more efficiently as barriers obstructing grain growth than micro-sized particles. Contrary, the lower electrical conductivity of Cu-1 wt% Al compacts is the result of higher electron scatter caused by nano-sized Al2O3 particles.
10.1016-j.jmatprotec.2008.03.034	16	wear; composite; composites; powders; milling; particles; powder; wt; sliding; friction; hardness; matrix; mechanical; surface; properties	In this study, the electrical performance of ODS Cu-based contact materials produced by mechanical alloying (MA) was investigated. Cu-based powder mixtures that contain various oxides at different proportions were milled by the high energy planetary ball mill for 5 h . Mechanically alloyed powder mixtures containing ZnO, Al2O3 and Y2O3 at the ratios of 1, 2, 4 and 6 wt% were pressed and sintered at 800 degrees C in vacuum environment. These compacts were then forged axially at the ratio of 75% at 650 degrees C so as to increase the density. At the first step, electrical conductivity experiments were applied to these samples to determine the best conductivity Results showed that, reinforced Cu samples containing 4% oxides exhibited the best. At the second step, contact count experiments were made with these samples for determining contact performance for the counts of 3000, 6000 and 9000 turn on/off. The samples of 4 wt% ZnO, 4 wt% Al2O3, 4 wt% Y2O3 reinforced Cu materials, respectively, exhibited both the best conductivity and the best contact performances.
10.1016-j.jmatprotec.2008.05.023	-1		The microstructure, mechanical properties and seawater corrosion resistance of annealed Cu-30Ni alloy tube were investigated using mechanical test, optical microscope, scanning electronic microscope and electrochemical measurement system, respectively. The recrystallizations gradually increased with the increase of annealing temperature and holding time. The hardness and tensile strength, which maintained invariability with annealing temperature at 680-720 degrees C, dramatically decreased with annealing temperature at 720-770 degrees C. As annealing temperature and holding time increase, corrosion potential (E-C) increased while corrosion rate (i(C)) decreased at the beginning of seawater immersion. But after 15 days' seawater immersion, as annealing temperature and holding time increase, E-C firstly increased and then decreased, on the contrary, i(C) firstly decreased and then increased. The Ni-rich surface film and the Ni-rich sub-grains were responsible for the initial and extended immersion, respectively. It was found that the Cu-30Ni alloy tube annealed at 720 degrees C for 30 min exhibited favorable comprehensive mechanical properties and seawater corrosion resistance. (C) 2008 Published by Elsevier B.V.
10.1016-j.jmatprotec.2009.10.012	-1		A novel Cu matrix composite reinforced by ZnO particulates has been prepared via a powder metallurgy technique. Resultant materials were characterized by means of scanning electron microscopy (SEM). X-ray diffraction (XRD) and energy dispersive X-ray spectroscopy (EDS) techniques. Microscopic observation exhibits a homogenous distribution in Cu Matrix of ZnO particulates, and the analysis of bending fracture surface reveals a relative good interfacial bonding. Performance tests indicate that the hardness of the composite has been significantly enhanced, while the electrical conductivity remains at a fairly high level. Both ZnO content and fabrication processes can obviously affect the properties of the composite. With increasing the mass fraction of ZnO. the relative density and electrical conductivity decrease monotonously, while the hardness exhibits non-monotonous change. Repressing and re-sintering process lead to increased relative density, electrical conductivity and hardness. While due process of plastic deformation results in further increased density and hardness, but decreased electrical conductivity.
10.1016-j.jmatprotec.2011.06.002	6	grain; deformation; strain; strength; dislocation; cu-; tensile; size; ecap; grain size; sfe; ductility; hardening; high; stress	It was found that the dendritic microstructure of an as-cast alloy was changed to an almost equiaxed alloy after 480 min of annealing at 700 C. The electrical conductivity of as-cast and hot rolled samples increased from 27.36 and 30.51% IACS to 30.67 and 32.1% IACS after 480 min of annealing at 700 C. The dendritic microstructure and the electrical conductivity values of an as-cast alloy annealed for 60 min remained almost unchanged when the annealing temperature was increased to 800 C. The hardness values of the samples that were hot rolled and annealed for 60 min were higher than those of the as-cast samples for all annealing temperatures. The electrical conductivity values of the hot rolled and as-cast samples were almost the same after annealing at 800 C for 60 min. It was shown that after 20% cold work, the electrical conductivity value of the as-cast sample decreased from 30.5% IACS to 22.6% IACS. The electrical conductivity values of the samples were not significantly changed when the cold work was increased from 20% to 60%. The electrical conductivity values of the 20%, 40% and 60% cold worked samples increased from 22.62, 24.69 and 26.63 to 27.14,28.36 and 30.55% IACS, respectively. after 30 min annealing at 400 degrees C.
10.1016-j.jmatprotec.2017.07.035	-1		A Cu/Al/Cu clad strip was produced successfully by the powder-in-tube method. The interface morphology, element distribution, peeling strength and tensile strength of the clad strips after annealing and further cold rolling were investigated. The experimental results indicate that the diffusional width of the intermetallic layer will increase with the annealing temperature, but the average peeling strength of the Cu/Al/Cu clad strip rises first and then falls. Further cold rolling process can significantly reduce the thickness of the intermetallic layer and improve the average peeling strength of the Cu/Al/Cu clad strip except for those annealed at 550 degrees C. There exists an optimal diffusional thickness (approximately 15.4 mu m) for the annealed Cu/Al/Cu clad strip processed by the powder-in-tube method. The clad strips annealed at 450 degrees C and further cold rolled to 0.5 mm can obtain the best mechanical performance, the peeling strength, ultimate tensile strength and elongation are 17.8 N/mm, 286 MPa and 9.4%, respectively. The peeling surfaces, peeling tests and tensile tests prove that compact and uniform intermetallic compounds can provide excellent performance for Cu/Al/Cu clad strips.
10.1016-j.jmatprotec.2018.08.034	-1		In this study, the effect of ultrasound as an alternative melt refinement technique of commercially available brass alloys and its impact in the microstructural and mechanical properties is analysed. A Cu-Zn alloy was cast in different conditions: without melt treatment, chemically refined and ultrasonically refined at different temperatures. Ultrasonic treatment was found to be more efficient than chemical refinement, promoting lower grain size and higher roundness of the alpha-phase and decreased the ratio of the alpha/beta phases. The best results were achieved for 940 degrees C melt refinement temperature. The microstructure morphology improved the alloy mechanical properties, namely ultimate tensile strength, yield stress and elongation, which attained 386 MPa, 192 MPa and 11.5%, respectively, for that melt refinement temperature.
10.1016-j.jmatprotec.2019.03.020	-1		Large diameter rods of Cu-Al-Mn shape memory alloy were gas tungsten arc welded. The microstructural evolution was studied by electron microscopy techniques and its impact on the mechanical and functional response of the welded joints was assessed. The fusion zone exhibited a mixture of alpha and beta phases, while the base material was composed only by the parent beta phase. The refined grain structure of the fusion zone increased the material ductility and can improve the functional fatigue resistance of the welded joint when compared to the original base material.
10.1016-j.jmatprotec.2019.116290	-1		A solution heat treatment followed by aging is typically used for age-hardening of non-ferrous alloys. In the present work, a novel strengthening route was designed for upward continuous casting of copper-based alloy rods. This route excluded a solution heat treatment and allowed aging prior to the deformation processes. The tensile strength of the copper-based rods (with only 0.26 wt% Cr) reached 560 MPa. Furthermore, the microstructural evolution of these rods was characterized via microscopy and X-ray diffraction. The contributions of grain boundaries, precipitates, and dislocations to the strengthening of the rods were calculated, thereby revealing the strengthening mechanism.
10.1016-j.jmatprotec.2020.116880	-1		How to coordinate the strength, ductility and electrical conductivity of Cu-Cr-Zr alloys has always been a difficult problem. Unlike most of previous reports on processing soft state (solution state) alloys, in the present study, a hard state (aged state) Cu-Cr-Zr alloy was subjected to one-step friction stir processing (FSP) at room temperature with more attentions paid to the evolution of grains and precipitates, and their effects on the mechanical and electrical properties. The results showed that the precipitates played a key role in grain refinement, and ultrafine grains (UFG) with an average size of 250 nm were produced after FSP. Many fine precipitates (average size of 3.1 nm) were uniformly distributed in the grains, neither dissolved nor obviously coarsened. Excellent comprehensive properties of high tensile strength (702 MPa), good elongation (16%) and electrical conductivity (74.3% IACS) were achieved in the FSP sample. Furthermore, this one-step FSP method does not need subsequent aging treatment which is indispensable for conventional processing methods, providing a simplified and efficient method for improving the performance of Cu-Cr-Zr alloys.
10.1016-j.jmatprotec.2021.117332	-1		The high optical reflectance of Cu at near-infrared wavelengths narrows the process window to fabricate Cu parts by laser powder bed fusion (LPBF). Coating powders with optically absorptive materials has been investigated to improve processability and enhance part properties. However, given the intense heat localization and thin coating layers relative to the powder, the mechanisms of thin film coating interaction in LPBF remain unclear, despite recent work showing the importance of the near-track environment in deposition behavior. In this study, optically absorptive Zn-coated Cu powders were prepared by physical vapor deposition and characterized. Single LPBF tracks were fabricated to elucidate material incorporation phenomena influenced by the volatile Zn coating. It is shown that Zn-coated powder enhances accretion at fastest effective scan speed tested (100 mm/s), where mean track volumes are increased from 0.72 +/- 0.05 mm3 (as-received) to 0.91 +/- 0.01 mm3 (Zn-coated). This has been correlated to the stronger vapor jet from the volatile Zn-coating, which denudes the surrounding powder bed. This exhausts the powder bed at slower effective scan speeds, causing instability and balling when compared to the as-received powder. It is shown that Zn is localized at the track surface and is undetectable in the track bulk, indicating Zn vaporization on interaction with the incident beam. Zn present mainly occurs through secondary deposition mechanisms like spatter and condensation, rather than in-process alloying. Coating powder feedstocks for use in LPBF therefore affects composition, laser beam absorptivity, and the neartrack vapor environment that is known to influence material incorporation behavior.
10.1016-j.jmatprotec.2021.117393	3	sma; shape; shape memory; memory; smas; superelastic; bars; damping; cu-al-mn; mechanical; bending; applications; numerical; sma bars; material	Additive manufacturing (AM) allows printing parts of complex geometries that cannot be produced by standard technologies. Besides, AM provides the possibility to create gradient materials with different structural and physical properties. We, for the first time, printed gradient soft magnetic materials from paramagnetic powders (316L steel and Cu-12Al-2Fe (in wt%) aluminium bronze)). The magnetic properties can be adjusted during the in-situ printing process. The saturated magnetization value of alloys reaches 49 emu g(-1). The changes in the magnetic properties have been attributed to the formation of the BCC phase after mixing two FCC-dominated powders. Moreover, the phase composition of the obtained gradient materials can be predicted with reason-able accuracy by the CALPHAD approach, thus providing efficient optimization of the performance. The obtained results provide new prospects for printing gradient magnetic alloys.
10.1016-j.jmatprotec.2022.117575	-1		In this study, a novel approach of powder surface alloying is proposed to address the issue of insufficient densification of printed copper (Cu) from high laser-absorbing Ni coated Cu powder through laser powder bed fusion. Three types of powder consisting of original Ni-coated powder (surface adhesion), partially Ni-diffused powder (partial surface alloying) and surface Ni-alloyed powder (complete surface alloying) were adopted to validate the effectiveness of the approach . All these powders significantly decreased the high laser reflectivity of Cu powder. The surface Ni-alloyed powder successfully melted the Cu powder to eliminate the lack-of-fusion pores in the printed Cu samples such that best dimensional accuracy and highest relative density of up to 99.6% was obtained. The interface condition between outer Ni coating and Cu powder played an important role in the densification process. The solid solution Ni in the surface Ni-alloyed powder maximized the contact area, reduced the thermal resistance and enhanced heat transfer efficiency, which eventually promoted the melting of Cu powder and eliminated the lack-of-fusion pores. Ni content is also revealed as an important factor in balancing electrical conductivity and mechanical properties. The optimal Ni content has been determined as 0.4 wt% for powder with surface Ni-alloyed.
10.1016-j.jmatprotec.2023.118169	-1		Coating high laser-absorptivity alloying elements on Cu powder is effective in enhancing its compatibility with laser powder bed fusion (LPBF) but significantly sacrifices the electrical conductivity because of the distortion in the lattice structure of Cu matrix. To overcome this issue, high laser-absorptivity W nanoparticles with excellent stability were incorporated onto Cu powder through a novel powder coating approach . Experimental results indicated that W-coating significantly reduced the laser reflectivity of Cu powder, enabling the complete melting of powder. Minor addition of W-coating improved the relative density to greater than 98.5% even at a high scanning speed of 800 mm/s. During the LPBF process, the evolution of W started with sintering of partial W -coating nanoparticles and agglomerations prior to the melting of Cu powder. Subsequently, the remaining was submerged into the Cu melt because of the capillary forces. After solidification, W was finally present in two forms: agglomerations localized around the melt pool boundary and nanoparticles dispersed in the Cu matrix. No significant solid solution was detected in the solidified Cu matrix. Scanning speed played a key role in determining the sintering behavior of W-coating at the early stage of LPBF and can be employed to tune the proportion of agglomerations and nanoparticles. Under the optimized printing conditions, a near-fully dense Cu component with excellent electrical conductivity (96%IACS) was obtained by printing 0.5 vol% W-coated Cu powder, which was superior compared with the reported data of printed Cu components incorporating other laser-absorptivity enhancers.
10.1016-j.jmatprotec.2024.118344	-1		Multi-material laser beam powder bed fusion (PBF-LB) is a promising approach to meet industrial demands for multifunctional components, due to its enhanced freedom of design. Copper and stainless steel are interesting materials to be combined due to the high electrical and thermal conductivity of copper and the mechanical strength and wear resistance of steel. However, this system suffers from copper contamination cracking (CCC), a phenomenon which leads to intergranular cracking of the steel due to penetration of liquid copper. The more these materials intermix, the greater the amount of copper that can penetrate and damage the steel. Mixing is more intense when steel is below copper during printing, a situation that cannot always be avoided due to design constraints. In this sense, this research tackles the worst scenario of printing CuCrZr onto 316L and analyses the effect of beam shaping on interface quality. For the first time, a ring-mode laser was applied to multi-material PBF-LB with the goal to reduce intermixing. It was observed that using a ring-mode laser source instead of a Gaussian beam decreases mixing of the two alloys and reduces interface defects, albeit being unable to completely suppress cracking. Grain size and texture were also affected by the beam shape, with the Gaussian beam leading to formation of small equiaxed grains along 20 layers of CuCrZr, resulting in random texture. The ring-mode laser source, on the other hand, yields columnar grains and <100> texture along the build direction. Both beam shapes were observed to induce supercooling below the liquid miscibility gap in the Cu-Fe system. Besides the expected gamma-Fe and epsilon-Cu phases, iron was also found to crystallize in a body-centered cubic (BCC) lattice structure, which is believed to happen due to Ni depletion of the steel in Cu-rich compositions, coupled to insufficient copper within the Fe-rich liquid during solidification. BCC fractions are higher for the Gaussian beam. These differences in microstructure and BCC fraction are attributed to the high intermixing of CuCrZr and 316L when applying Gaussian beams, which is around 10 times higher than with the ring-mode laser.
10.1016-j.jmatprotec.2024.118422	-1		To meet the higher device vibration reduction requirements, novel porous Cu 71 Al 18 Mn 11 shape memory alloys (SMAs) with controllable porosity were prepared using Cu, Al, and Mn elemental powders as raw materials. To further enhance the strength and damping performance of SMAs, a low-temperature reactive synthesis combined with spark plasma sintering (LTRS +SPS) process was used. In this paper, the effects of LTRS +SPS process on pore structure and texture, compressive strength, and damping properties of porous Cu 71 Al 18 Mn 11 alloy were studied. The outcomes indicated that LTRS +SPS process can effectively improve both compressive strength and damping properties. The associated closed pore structure caused by this process and the second phase gamma 2 phase formed by element diffusion result in a variety in compressive strength from 324.6 MPa to 617.9 MPa, which were 3.9 times that of the comparable porosity alloy with alloy powder as raw material by vacuum sintering. Meanwhile, the damping value changed from 0.27 to 0.10, which was 4.5 times that of the homogeneous dense alloy. The increase in damping property is caused by the increase of motionable interfaces in the matrix for the introduction of pores, which leads to the increase of energy dissipation. Besides. the interaction between the second phase gamma 2 and dislocation contributes to the improvement of damping, as well as the compressive strength . These findings in this paper provide new insights and references for the structural design and microstructure design of highperformance Cu-based alloys.
10.1016-j.jmatprotec.2024.118489	-1		Although nanocrystalline (NC) metals and alloys have been studied for nearly 40 years, their preparation is limited to the laboratory as large-scale; low-cost commercial production remains a challenge. In this study, highstrength bulk NC Cu -Al alloys were prepared from coarse-grained Cu -Al alloy rods via rotary swaging. Rotary swaging is characterized by the low cost and infinite length of the processed samples; therefore, it can advance the industrial application of bulk NC alloys. Core -shell-structured Cu -Al alloy rods with a hard NC core (diameter of 2.2 mm) wrapped in a soft ultrafine-grained (UFG) shell with a thickness of 1.75 mm were prepared using a rotary swage. Tensile tests revealed that the hard NC Cu -Al alloy core exhibited an ultimate tensile strength of 1034 MPa, which surpassed current strength records. Microstructural characterization showed that the hard NC core was composed of NC fiber grains with widths of 45 nm and lengths of 190 nm. The edge of the rod contained numerous low-angle grain boundaries and shear bands, which provided it with a lower strength and higher elongation than those of the center. During swaging, strong (200) and (111) fiber textures perpendicular to the cross-section were produced during the early stages of deformation. In the latter deformation stages, the polar densities of the (200) and (111) textures weakened, and some complex textures were formed along with high-angle grain boundaries. The grain refinement mechanisms were dominated by multiple deformation twinning, stacking faults, and dislocation slips. Finite elemental analysis showed that triaxial compressive stress and a high strain rate were applied to grain refinement. In addition, the softer shell protects the harder core during deformation, preventing fracture. This study verified an effective preparation technique for bulk NC materials via rotary swaging because it is a simple process with low cost and broad industrial prospects.
10.1016-j.jmatprotec.2025.118828	14	strength; properties; conductivity; electrical; mechanical; cu-; grain; mpa; electrical conductivity; aging; precipitation; phase; mechanical properties; tensile; phases	To explore the formability of ultrafine-grained (UFG) materials, hemispherical spinning tests are conducted on the UFG Cu for the first time. The limit half-cone angle of spinning for UFG Cu is experimentally determined to be 15.2 degrees, slightly higher than the 7.84 degrees for coarse-grained (CG) Cu, despite UFG Cu exhibiting significantly lower tensile ductility than the latter. The exceptional formability of UFG Cu is primarily attributed to the mechanism of deformation-induced dynamic recovery during spinning, which promotes dislocation absorption via grain boundary migration and releases the strain/strain concentration at grain boundaries. Finite element method (FEM) simulations confirm that fracture in both UFG and CG materials predominantly occurs in the cone wall region due to its biaxial tensile stress state. In contrast, the spinning deformation zone exhibits a triaxial compressive stress state, which serves as an optimal constraint for accommodating large plastic strains within large ranges of strain rates. By adjusting key processing parameters, such as feed ratio and rotational speed, the extent of dynamic recovery can be effectively activated and enhanced. These findings provide new insights into the plastic forming behavior of UFG Cu and expand its potential for engineering applications.
10.1016-j.jmatprotec.2025.118868	-1		Currently, the simultaneous enhancement of mechanical strength and ductility in porous composite alloys remains a formidable challenge. To address this limitation, we have innovatively synthesized in-situ nanoscale amorphous Al2O3 in porous composite Cu-Al-Mn (CAM) alloys utilizing a well-orchestrated staged powder metallurgy (PM) process, employing Cu, Mn, and oxygen-containing Al elemental powder as raw materials. In the optimized porous CAM/Al2O3 processed by staged PM, strong equiaxed crystals in average grain size 29.20 mu m with a near-unity aspect ratio, and the pore soft phase characterized by pore sizes ranging from 0.1 to 10 mu m and its porosity of 33.20 % was found. Crucially, in-situ formation of amorphous Al2O3 nanoparticles strategically positions themselves along grain boundaries and pore edges, constructing a protective shell structure that safeguards grains against fracture under severe compressive deformation. This protective architecture, coupled with the abundant soft phase providing ample deformation accommodation, facilitates an exceptional balance of strength and ductility. Consequently, a remarkable enhancement in ultimate compressive strength (similar to 570.6 MPa) by 1.8 times is achieved, while maintaining a ductility capability (similar to 44.3 %) 3.0 times that of comparable porosity porous CAM alloy. The staged PM process for fabricating porous Cu-Al-Mn alloys with high strength and ductility via utilizing partially oxidized Al powder as one of the raw materials without relying on the difficult-to-obtain microstructure required in high strength structural materials. This approach demonstrates the capability of staged PM process in fabricating high performance porous Cu-Al-Mn alloys with controllable structures.
10.1016-j.jmmm.2003.12.1208	9	magnetic; magnetization; magnetoresistance; temperature; superparamagnetic; annealing; gmr; field; magnetic properties; ferromagnetic; granular; samples; magnetic field; melt-spun; particles	The relation of giant magnetoresistance and nanoscopic segregated phases in Cu90Co10 melt-spun ribbons is investigated using several techniques. The magnetoresistance, the resistivity and the magnetization increase with isochronous anneals. At higher temperatures an irreversible region is observed where the resistivity decreases and the magnetoresistance has a maximum. Lamellar microstructures of parallel nanostripes are seen with transmission electron microscopy in the structural grains. We investigate these nanophases using a nonlinear Cahn-Hilliard diffusion equation.
10.1016-j.jmmm.2004.11.471	-1		High-energy ball milling was used to prepare a magnetoresistive granular alloy composed of Fe70Co30 magnetic clusters dispersed in a Cu matrix. Two milling processes were tested. The first process consists of milling a mixture of pure Cu, Fe and Co powders. The second process consists of milling a mixture of Cu and Fe70Co30 powders. The first milling process leads to the formation of a Cu-Fe-Co solid solution after 20 h of milling. This solid solution was subjected to annealing treatments to obtain a granular structure. After annealing at 415 degrees C for I h, the magnetoresistance reaches its optimum (16% at 5K). With the second process, the Fe70Co30 phase is directly dispersed in the Cu matrix. After 20h of milling, the structure of the powder is similar to that obtained from the first process followed by annealing at 415 degrees C, but the magnetoresistance is lower (5% at 5 K).
10.1016-j.jmmm.2006.02.158	-1		(Fe,Co)- Zr,Hf)-Cu-B (HITPERM-type) alloys with variable Hf, Zr and Co content were isothermally crystallised at 500-650 degrees C for 1 h, and the optimum nanocrystallisation temperature was selected on the basis of the minimum coercive field at room temperature. The quasistatic hysteresis loops were measured at temperature from 20 to 650 degrees C. Subsequently, the optimally annealed alloys were subjected to long-term annealing at 500, 550 and 600 degrees C. Working temperature of 600 degrees C is too high for the investigated alloys to maintain stable magnetic properties. Temperature of 550 or 500 degrees C permits the material to be magnetically stable for a long period. The magnetic hysteresis loops recorded for the nanocrystalline alloys, where Fe:Co ratio is close to 1 and refractory metals content is 7 at%, prove that coercive field increases slightly with temperature, but remains in the range of 20-40 A/m (depending on the alloy composition) from 20 to 550 degrees C. This proves that the investigated alloys, after optimisation of chemical composition, may be suitable for high temperature use.
10.1016-j.jmmm.2006.07.011	-1		The present study concerns magnetic behavior of nanocrystalline Cu-Ni, Cu-Fe and Cu-Ni-Fe alloys prepared by mechanical alloying. It has been found that the magnetic properties e.g. H-c, M-r and M-s of the nanocrystalline alloys were significantly influenced by the changes in microstructural constituents, grain size and evolution of phases. Microstructural changes in the alloys have been effected by carrying out isothermal treatments on the mechanically alloyed products in the temperature range of 450-650 degrees C. Phase evolution in the samples after the isothermal treatments were identified and characterized by X-ray diffraction (XRD) and differential scanning calorimetric (DSC) techniques and the results were correlated with the magnetic properties of the alloys.
10.1016-j.jmmm.2008.02.133	9	magnetic; magnetization; magnetoresistance; temperature; superparamagnetic; annealing; gmr; field; magnetic properties; ferromagnetic; granular; samples; magnetic field; melt-spun; particles	The results of transmission electron microscopy (TEM), magnetic and magneto-resistivity investigations of the Cu-10Co (wt%) giant magneto-resistance (GMR) melt-spun ribbons are reported and discussed. To obtain different distributions of ferromagnetic Co particles in a non-magnetic Cu matrix, the alloy was aged at 550 degrees C for 0.5, 1, 2, 16, and 32 h . Particle size measurements were performed using quantitative TEM metallography methods. Two size classes of Co particles are identified: primary particles (P) precipitated during the melt-spinning process and the secondary particles (S) precipitated during the ageing process. The results of magnetization and coercitivity are correlated with the results of calculations based on the real Co particle distributions determined from TEM micrographs. The behavior of magnetization and coercive force in function of ageing time is explained as related with changes of a mean particle size. It is shown that the GMR effect is not influenced by Co particles distribution for the S particles with the mean size less than 10 nm, whereas for Co distributions with larger mean diameters, the GMR effect is strongly reduced.
10.1016-j.jmmm.2010.10.041	9	magnetic; magnetization; magnetoresistance; temperature; superparamagnetic; annealing; gmr; field; magnetic properties; ferromagnetic; granular; samples; magnetic field; melt-spun; particles	Cu-Mn-Al melt-spun ribbons of two compositions were studied to find out the influence of the collective behavior of diluted ferromagnetic nanoparticles on magnetotransport properties. The sample with a lower volume percentage of particles demonstrates magnetic behavior characteristic for the superparamagnetic state while the other one demonstrates ferromagnetic-like ordering. It is shown that the collective behavior of the system in both ribbons correlates with the temperature dependence of magnetoresistance.
10.1016-j.jmmm.2011.06.005	-1		We present here a detailed study of electronic transport properties of the metallic-ferromagnetic compounds Cu1+xCr2Te4, having excess Cu atoms with x=0-1, from 2 to 400 K. The stuffing of the copper atoms in the parent structure reduces the ferromagnetic ordering temperature T-C from 325 to 156 K, while for the entire range the dependence of the electrical resistance and the thermopower with temperature and the anomalies in them on the magnetic ordering remain similar. All the compounds show a magnon-drag contribution in thermopower as a positive maximum around T-C/3, and a T-2-dependence of resistivity at low temperatures. The increasing effects of the short range magnetic ordering in the paramagnetic resistivity are seen with the increase in the stuffing of atoms in these compounds. The transport properties are explained by the current carriers-the holes in a wide energy band dominated by the p-state of Te-atoms, which are scattered by the spindisorder in the paramagnetic phase and from the magnons in the ferromagnetic phase.
10.1016-j.jmmm.2012.04.009	-1		The current state of studies presents the effect of ternary addition of transition elements such as Mn, Cr and Si (10 wt%) on the mechanically driven non-equilibrium solubility of 40 wt% Co containing Cu-Co alloy. X-ray powder diffraction analysis indicates that addition of Mn has been found to be the most effective in enhancing the solubility and formation of a complete solid solution between Co and Cu in a short duration (30 h) of ball milling. The microstructure of the ball milled Cu-Co-Mn alloy was found to be stable after the isothermal annealing up to a temperature of 450 degrees C for 1 h . The magnetic properties such as magnetic saturation, coercivity and remanence of ball milled Cu-Co alloy in the presence of Mn significantly altered after annealing in the temperature range 350-650 degrees C for 1 h . The best combination of magnetic properties of Cu-Co-Mn alloy has been found after annealing at 550 degrees C for 1 h .
10.1016-j.jmmm.2013.04.029	-1		In order to improve solubility and magnetic properties, the ball milling technology was used for the production of 50Cu-40Fe-10Mn (wt%) alloy. The effect of Mn content on the microstructure and magnetic properties of Cu-Fe alloy was also investigated in detail. Microstructure and magnetic properties of the alloy were analyzed by X-ray diffraction, differential scanning calorimetry, high resolution transmission electron microscopy and superconducting quantum interface device magneto-metry. The results showed that a complete solid solution of the alloy was produced after 30 h of milling. Quantitative phase analysis of X-ray diffraction data revealed that the milled alloy obtained after isothermal annealing at 550 degrees C for 1 h consisted of Cu (54.52 wt%), alpha-Fe (36.49 wt%) and MnO (8.99 wt%). The milled alloy obtained after annealing at 450 degrees C for 1 h leads to the maximum values of magnetic properties such as coercivity=438 Oe, remanent magnetization=14.3 emu/g, and saturation magnetization=51 emu/g.
10.1016-j.jmmm.2014.08.003	-1		We report the magnetic, magnelocaloric, and magnelolransporl properties of the semi-Heusler alloy Cu(0.85)Ni(015)MnSla, which exhibits coexistence of antiferromagnetic (AFM) and ferromagnetic (FM) phases. A broad magnetic phase transition is evident from the temperature variations of magnetization, heat capacity, and isothermal magnetic entropy change. This is due to the presence of both AFM and FM phases at low temperatures. The variation or electrical resistivity with temperature shows three distinct regions of magnetic phases. The magnetoresistance (MR) results also show the presence of AFM and FM phases at temperatures below 45 K, and a FM phase at temperature above 45 K. Though there is no signature of a spin-glass state at low temperatures, various results point towards the presence of shortrange magnetic correlations at low temperatures. (C) 2014 Elsevier B.V. All rights reserved,
10.1016-j.jmmm.2015.07.068	-1		A theoretical study of the ground state properties of alloys with compositions along the pseudobinary line Cu3Al-Cu2AlMn is presented. Cohesive energies, lattice parameters and magnetic moments of the two limiting compounds and three intermediate compositions are calculated by means of density functional theory. In order to evaluate the role of magnetism, both the spin-polarized (SP) and the non spin-polarized (NSP) cases have been considered. It is shown that magnetism plays a central role on the stabilization of the L2(1) crystal structure in Cu2AlMn, and in the formation of the miscibility gap in Cu3Al-Cu2AlMn. The considerable lattice mismatch between the end compounds can be attributed also to magnetic effects.
10.1016-j.jmmm.2015.08.073	13	clusters; atomic; glass; atoms; composition; dynamics; metallic; icosahedral; glasses; simulations; molecular; cu-zr; molecular dynamics; metallic glasses; structural	We perform a systematical analysis of the spin Hall effect (SHE) in the Cu alloys doped with a series of 5d elements, by the combined approach of density functional theory and Hartree-Fock approximation. We find that not only the spin orbit interactions (SOI) in both the 5d and 6p orbitals, but also the local correlations in the 5d orbitals of the impurities, are decisive on the sign of the spin Hall angle (SHA). Including all of these three factors properly, we predict the SHA for each alloy in the series. The signs of Culr and CuPt are sensitive to perturbation of the local correlations. This observation is favorable for controlling the sign of the transverse spin Hall voltage.
10.1016-j.jmmm.2016.08.029	-1		Microstructure and magnetic behavior of nanocrystalline 50Cu-40Co-10Si (at%) alloy prepared by mechanical alloying and subsequent isothermal annealing in the temperature range of 450-650 degrees C have been studied. Phase evolution during mechanical alloying and isothermal annealing is characterized by X-ray diffraction (XRD), differential thermal analyzer (DTA), high resolution transmission electron microscopy (HRTEM) and magnetic measurement. Addition of Si has been found to facilitate the metastable alloying of Co in Cu resulting into the formation of single phase solid solution having average grain size of 9 nm after ball milling for 50 h duration. Annealing of the ball milled alloy improves the magnetic properties significantly and best combination of magnetic properties has been obtained after annealing at 550 degrees C for 1 h duration.
10.1016-j.jmmm.2017.06.081	-1		Copper-permalloy [Cu-1 (x)(Ni80Fe20)(x)] alloy films were deposited by co-sputtering and their chemical, structural, magnetic, and electrical properties were characterized. These films are found to have favorable weak ferromagnetic properties for low temperature magnetoelectronic applications. Our results show that by varying the composition, the saturation magnetization (M-s) can be tuned from 700 emu/cm(3) to 0 and the Curie temperature (T-c), can be adjusted from 900 K to 0 K. The M-s and T-c are found to scale linearly between x = 25% and 100%. Electronic structure calculations are used to provide a strong fundamental understanding of the mechanisms responsible for establishing the observed electrical and magnetic properties. The theoretical results also show that the introduction of Cu into the permalloy lattice results in very strong spin scattering in the minority spin channel, with only moderate interactions in the majority channel.
10.1016-j.jmmm.2018.11.077	16	wear; composite; composites; powders; milling; particles; powder; wt; sliding; friction; hardness; matrix; mechanical; surface; properties	The present work has been made to improve the micro-hardness, wear resistance, low coefficient of friction and surface roughness of Cu-Ni-P-W-TiO2 hybrid composite coated Al6063 substrate which was made by electro-deposition process. Cu-Ni-P-W-TiO2 hybrid composite was electrodeposited from the modified Nickel-Watts bath solution. Coated substrates were heat-treated at various temperatures for 1 h and then the effect of heat treatment on the coating concert was studied. The inter-metallic structure was identified by Scanning Electron Microscopy (SEM) and Energy Dispersive X-ray (EDX) Spectroscopy analysis. The micromechanical behavior of the coated substrates were investigated by various mechanical tests like wear, vicker's-microhardness, surface roughness and friction. Hence the results shows that when the addition of phosphorous (P) and tungsten (W), the grain size refined gradually and the micro-hardness improved apparently. Also it is found that during the heat treatment of Cu-Ni-P-W-TiO2 coated Al6063 substrates at 300 degrees C, wear resistance is improved, coefficient of friction and surface roughness were reduced. This hybrid composite coating shows significantly that improves the micro-mechanical properties comparing with other composite coatings. From this VSM results, it was found that all the coated samples shows magnetic nature of the materials with lesser magnetization and coercivity values.
10.1016-j.jmmm.2018.12.013	9	magnetic; magnetization; magnetoresistance; temperature; superparamagnetic; annealing; gmr; field; magnetic properties; ferromagnetic; granular; samples; magnetic field; melt-spun; particles	This research presents the study on the structural-phase states and magnetoresistive properties of thin nano granular film alloys based on Cu and Co with a total concentration of Co in the range of 15 <= x <= 71 at%. The analyses for the unannealed and annealed thin films with a thickness d = 20 nm, have been performed. The films have been annealed in the temperature range from 300 to 800 K for 20 min. It found that the heat treatment within the range from 600 to 800 K led to an increase in the magnetoresistance and coercive force due to the growth of Co granules size under heat treatment and partial decomposition of the fcc-Cu(Co) solid solution. The highest magnitudes of the magnetoresistance were found in the as-deposited film alloys featured by the total concentration of Co x = 21 at%, which consist of Cu(Co) solid solution made of fcc-Cu and superparamagnetic Co granules (size L = 2 divided by 5 nm). Interestingly, the thin film alloys with an increased concentration of Co x >= 50 at% exhibited anisotropic magnetoresistance.
10.1016-j.jmmm.2021.168645	-1		Bi-doped Cu alloys are promising materials in the field of Spintronics due to the possibility of having efficient charge to spin conversion via spin Hall effect. To explore this effect, in particular at the nanoscale, it is essential to have a growth method that allows the control of crystal quality, cluster formation and microstructure. In this paper, we demonstrate that electrochemical deposition is a suitable method for the synthesis of these nanomaterials. We report the growth, by template assisted electrodeposition, of high quality, homogeneous nanowires of a diluted alloy of Bi dispersed into a Cu matrix, in which Bi concentration can be easily varied by tuning electrolyte composition. Structural analysis shows that Bi does not cluster but incorporate into the Cu matrix. The short-range order is nevertheless affected by the deposition potential. Cu is basically metallic, and Cu-Cu nearest-neighbor distances are those of bulk Cu, so Bi enters into the Cu structure substitutionally. Using low overpotential, we demonstrate the possibility of growing single crystal nanowires.
10.1016-j.jmmm.2022.169407	-1		The Cu-6.5Fe-(0, 0.1, 0.3 and 0.5 wt%)Mg ingots were prepared to explore the influence of Mg addition on its physical and mechanical properties. The results indicated that the addition of Mg element suppresses the segregation and coarsening of the Fe phases. The reflection loss effect of the Fe fibers on electromagnetic wave is stronger than that of precipitated phase and grain boundary. The addition of Mg element significantly increases the density of the Fe fibers, resulting in more excellent physical and mechanical properties of the Cu-6.5Fe-0.3Mg alloy. Its electromagnetic shielding value with a thickness of 0.6 mm reached 83 dB at 1000 MHz after aging at 400 degrees C for 1 h, which was 40 dB and 10 dB higher than that of the pure Cu and Cu-6.5Fe alloy, respectively. And its conductivity and hardness reached 64.9% IACS and 167.1HV, respectively. It had a wide range of application prospects in the fields of 5G communication and industrial robots.
10.1016-j.jmmm.2022.169702	9	magnetic; magnetization; magnetoresistance; temperature; superparamagnetic; annealing; gmr; field; magnetic properties; ferromagnetic; granular; samples; magnetic field; melt-spun; particles	Permalloy copper (CuPy) structures, produced by low cost vacuum free pulsed electrodeposition technique, present relevant results as magnetic material properties hardening and Curie temperature decay in function of Cu concentration. Such properties modification are here related to the slight crystalline phase shift of face cubic centered (FCC) structure to lower angles, evidenced by X-ray measurements, with lattice parameter increase and successively magnetization weakening by Ni atoms substitution by Cu. The fine tuning of Curie temperature decrease reported here, Tc approximate to 800K from pure Permalloy to Tc approximate to 380K for alloy with 67% of Cu, could allow utilization of such technique to develop magnetic sensors and memories with thermal activation achieved near room temperature.
10.1016-j.jmps.2018.02.017	-1		The paper addresses one of the most important yet overlooked phenomenon in shape memory research- the plastic slip response. We show that the slip response is highly crystal orientation dependent and we demonstrate the precise reasons behind such complex response. The fractional dislocations on <111> {012} or <111> {011} systems can be activated depending on the sample orientation and solutions are derived for the variations in disregistries and dislocation core spreadings. This leads to the calculation of critical resolved shear stress in close agreement with experimental trends. The results show considerable dependence of the flow behavior on the non-Schmid stress components and the proposed yield criterion captures the role of stress tensor components.
10.1016-j.jmrt.2016.10.003	-1		The microstructures, phase characteristics and mechanical behaviour of Cu-Zn-Al alloys modified with Fe, B, and Fe-B mixed micro-alloying additions has been investigated. Cu-Zn-Al alloys were produced by casting with and without the addition of the microelements (Fe, B and Fe-B). The alloys were subjected to a homogenisation-cold rolling annealing treatment schedule, before the alloys were machined to specifications for tensile test, fracture toughness, and hardness measurement. Optical, scanning electron microscopy and X-ray diffraction analysis were utilised for microstructural and phase characterisation of the alloys. A distinct difference in grain morphology was observed in the alloys produced-the unmodified alloy had predominantly needle-like lath martensite structure with sharp grain edges while significantly larger transverse grain size and curve edged/near elliptical grain shape was observed for the modified Cu-Zn-Al alloys. Cu-Zn with fcc structure was the predominant phase identified in the alloys while Cu-Al with bcc structure was the secondary phase observed. The hardness of the unmodified Cu-Zn-Al alloy was higher than that of the modified alloys with reductions in hardness ranging between 32.4 and 51.5%. However, the tensile strength was significantly lower than that of the modified alloy grades (28.37-52.74% increase in tensile strength was achieved with the addition of micro-alloying elements). Similarly, the percent elongation and fracture toughness (10-23% increase) of the modified alloy was higher than that of the unmodified alloy grade. The modified alloy compositions mostly exhibited fracture features indicative of a fibrous micro-mechanism to crack initiation and propagation, characterised by the prevalence of dimpled rupture.(C) 2016 Brazilian Metallurgical, Materials and Mining Association. Published by Elsevier Editora Ltda. This is an open access article under the CC BY-NC-ND license
10.1016-j.jmrt.2017.07.002	6	grain; deformation; strain; strength; dislocation; cu-; tensile; size; ecap; grain size; sfe; ductility; hardening; high; stress	Early published results have demonstrated that high purity Cu and a Pb-62% Sn alloy exhibit very different behaviour during high-pressure torsion (HPT) processing at room temperature and subsequent room temperature storage. High purity Cu showed strain hardening behaviour with a refined grain structure during HPT processing whereas a Pb-62% Sn alloy displayed a strain weakening behaviour because the hardness values after HPT processing were significantly lower than in the initial as-cast condition even though the grain size was reduced. During room temperature storage after HPT processing, high purity Cu with lower numbers of rotations softened with the time of storage due to local recrystallization and abnormal grain growth whereas the Pb-62% Sn alloy hardened with the time of storage accompanied by grain growth . Through comparisons and analysis, it is shown that the low absolute melting point and the high homologous temperature at room temperature in the Pb-62% Sn alloy contribute to the increase in hardness with coarsening grain size during room temperature storage. (C) 2017 Brazilian Metallurgical, Materials and Mining Association. Published by Elsevier Editora Ltda. This is an open access article under the CC BY-NC-ND license.
10.1016-j.jmrt.2018.02.005	-1		Cyclic closed-die forging (CCDF) appears to be an easy to operate deformation process, which imposes high levels of strain, even on difficult-to-deform materials. However, despite said potential advantages, the CCDF at cryogenic temperatures has not yet been investigated. Copper samples with dimensions of 10 mm x 10 mm x 20 mm were processed in up to six passes with interpass rotation, enabling the samples to return approximately to their initial dimensions after each pass. The intensity and homogeneity of plastic deformation was evaluated by mapping the Vickers hardness over the entire surface of the sample, and the resulting maps were compared with the strain and stress distribution estimated by FEM numerical simulation. The deformed microstructures were examined by optical and transmission electron microscopy. Cryogenic CCDF has proved to be effective in suppressing the recovery mechanisms of Cu samples, resulting in finer and more heterogeneous strains distribution than those deformed at room temperature. However, long-term observations by TEM have shown that these microstructures are inherently unstable, so that hardness decreases 50% after two years. (C) 2018 Brazilian Metallurgical, Materials and Mining Association. Published by Elsevier Editora Ltda.
10.1016-j.jmrt.2019.01.012	-1		Work hardening is a common method of strengthening copper-based alloys. However, softening behavior is observed in Cu-Cr-Ti-Si alloy during cold rolling processes. Cold deformation greater than 85% can induce softening behavior. We used an electron backscatter diffraction system, X-ray diffraction, and transmission electron microscopy to analyze the microstructure of alloy samples subjected to different degrees of cold deformation. A greater proportion of high-angle grain boundaries, a lower dislocation density, and certain dislocation configurations indicated that the recovery takes place during heavy cold deformation leading to softening phenomenon. (C) 2019 The Authors. Published by Elsevier B.V.
10.1016-j.jmrt.2019.06.007	16	wear; composite; composites; powders; milling; particles; powder; wt; sliding; friction; hardness; matrix; mechanical; surface; properties	Functional grade composites Cu-10Sn-5Ni reinforced with 10 wt%SiC and 10 wt%Al2O3, respectively, and their alloy was developed through horizontal centrifuge cast technique. Sample composites and alloy were cast at cylindrical dimensions of Phi(out)100 x Phi(in)70 x 100 mm. They were later subjected to tribology analysis during non-lubricated sliding. Anti-wear performance variations at inner (0-8 mm) and outer (8-15 mm) wall thicknesses of both composites and alloy were experimented using pin-on-disc tribotester. Experimentation with increasingly varied parameters like load and slid distance showed a rising trend of wear and friction. This was observed while comparing between the least (10 N, 500 m) and highest (60 N, 3000 m) varied parameter; for both alloy and composites. Also, a proportional decline in coefficient of friction with increase in slid velocity was exhibited for both composites; whereas alloy showed a linear rise. Worn specimen analysis using scanning electron microscopy on both composites revealed Mechanically Mixed Layer formation at both zones. This caused reduction in friction coefficient at high velocity (6 m/s). (C) 2019 The Authors. Published by Elsevier B.V.
10.1016-j.jmrt.2019.06.019	15	aging; strength; conductivity; electrical conductivity; electrical; mpa; treatment; strengthening; degrees; cu-; cold; precipitation; tensile strength; tensile; iacs	A new process of hot rolling with intermediate annealing is developed to increase the strength and electric conductivity of the Cu-1Cr-0.1 Zr (wt%) alloy. The process can refine the crystalline structure and accelerate the speed of precipitation simultaneously, and a combination of high ultimate tensile strength of 522 MPa, excellent electrical conductivity of 81.9 %IACS has been achieved. The results show the higher strain rate and temperature, the higher speed of precipitation. In addition, the microstructure and property of the strip processed by HR-6 (7) over tilde 23 K is non-uniform through the thickness, and the top layer with (0) over tilde .2 mm thickness shows a higher tensile strength and electrical conductivity than that of the overall rolled sheet. (C) 2019 The Authors. Published by Elsevier B.V.
10.1016-j.jmrt.2019.09.054	6	grain; deformation; strain; strength; dislocation; cu-; tensile; size; ecap; grain size; sfe; ductility; hardening; high; stress	Ultrafine grained Cu-Nb alloys with minimal additions of 1 wt% Nb were prepared by using HPT at ambient temperature ((2) over tilde0 degrees C) and elevated temperature ((2) over tilde 00 degrees C). The microstructure, thermal stability and properties were investigated. The results indicated that compared with the Cu-1%Nb alloy processed at ambient temperature, the sample processed at 200 degrees C shows higher density and higher thermal stability, which contributed to its higher electrical conductivity and tensile strength after annealing treatment. (C) 2019 The Authors. Published by Elsevier B.V.
10.1016-j.jmrt.2019.11.015	6	grain; deformation; strain; strength; dislocation; cu-; tensile; size; ecap; grain size; sfe; ductility; hardening; high; stress	The high-temperature compressive deformation behavior of a Cu-10 wt% Sn solid solution alloy was studied in the temperature range of 843-993 K and in the strain rate range of 10(-3)-10 s(-1) and the relationships among the flow stress, strain rate and temperature were determined. Based on the data obtained from the compression tests, the deformation mechanism was identified, and the processing maps were constructed. The Cu-10Sn alloy exhibited solute drag creep at low strain rates and high temperatures and power law breakdown (PLB) at high strain rates and low temperatures. In the processing maps, above the temperature of 933 K, the alloy did not show flow instability up to a high strain rate of 10 s(-1) and showed high power dissipation efficiencies (31-35%) even at the very high strain rate of 10 s(-1). Furthermore, at 993 K, the fraction of dynamically recrystallized grains after compressive deformation was as high as 0.83 at 10 s(-1). These results indicate that the Cu-10Sn alloy exhibits a significantly better hot workability and a higher quality of post-deformation microstructures compared to the pure Cu where dislocation climb creep is the main deformation mechanism. Continuous dynamic recrystallization occurred at 843 K, while discontinuous dynamic recrystallization occurred at 993 K. Comparison of the current results with the previous work on the Cu-4.9Sn alloy indicates that the increase of Sn concentration in Cu matrix extends the regime of solute drag creep and delays the onset of PLB to a lower temperature and a higher strain rate. (C) 2019 The Authors. Published by Elsevier B.V.
10.1016-j.jmrt.2019.12.085	2	corrosion; surface; film; electrochemical; films; spectroscopy; layer; current; solution; potential; resistance; composition; x-ray; ions; showed	Copper and zinc alloys have applications in products exposed to harsh environments. Usually, these products have upon their surface a thin film of oxides, whose properties may change due to the exposure to air or aqueous solutions at room temperatures. This work analyzed copper and zinc alloy surfaces exposed to aqueous solutions of alcohol and a sugarcane liquor using mainly spectroscopic ellipsometry and confocal microscopy at room temperature. Using ellipsometry, oxide thickness was measured, either native ones or grown ones on the substrate exposed to air, and finally, those grown with the used solutions. Confocal microscopy was used to analyze the topography of the samples and measure their surface roughness in all processes. Besides, scanning electron microscopy with energy dispersion spectroscopy verified the composition of the elements present in the alloy, obtaining 70% Cu and 30% Zn. Surface roughness and oxide thickness were monitored by 29 days when the surfaces were exposed to air. Average roughness R-a varied from 0.165 mu m (day 1) to 0.222 mu m (day 29). Oxide thickness ranged from 4.755 nm (day 1) to 11.192 (day 29) in the same time interval when surfaces were exposed to air at room temperature. Roughness and thickness were also measured when the surfaces were exposed to aqueous solutions of alcohol and a sugarcane liquor at 1.5 h, 8 h, 24 h, and 48 h of exposure. The greatest variation for both average roughness R-a (0.232 mu m to 0.76 mu m) and oxide thickness (32.774 nm-68.105 nm) was observed when the surfaces were exposed to sugarcane liquor. (C) 2020 The Authors. Published by Elsevier B.V.
10.1016-j.jmrt.2020.01.036	-1		In the present work, mechanical and microstructural properties of Austempered Ductile Iron (ADI) alloyed with Cu-Ni-Mn-Mo submitted to different hot air austempering cycles in a two-step mechanism were evaluated. In the first step, cooling and austempering were performed in an experimental hot air blower device. In the second step, the austempering was performed in a muffle furnace. Bars with empty set16.5 mm and 90 mm of length were austenitized in an electric resistive furnace for 90 min at 860 degrees C. Austempering first step was performed for 10 min at 290 degrees C, 320 degrees C and 350 degrees C corresponding to cycles I, II and III, respectively. Austempering second step was performed for 60 min at 380 degrees C for all cycles. The measurements of Brinell hardness, elongation, yield strength, and ultimate tensile strength for cycle I were 288 HB, 5.0%, 840 MPa, and 988 MPa. For cycle II, the measurements were: 264 HB, 5.9%, 717 MPa, and 876 MPa. And for cycle III: 257 HB, 6.6%, 711 MPa, and 888 MPa. Microstructural analysis indicated the presence of pearlite- free ausferrite. (C) 2020 The Authors. Published by Elsevier B.V. This is an open access article under the CC BY-NC-ND license (http://creativecommons.orgnicensesiby-nc-nd/478).
10.1016-j.jmrt.2020.01.105	3	sma; shape; shape memory; memory; smas; superelastic; bars; damping; cu-al-mn; mechanical; bending; applications; numerical; sma bars; material	Shape memory alloys (SMAs) find important applications in many fields, including the biomedical, aerospace, and civil construction industries. The increasing interest in these materials arises from their mechanical properties such as shape memory effect, superelasticity, and damping capacity. In this work, porous samples of a Cu-Al-Ni-Mn-Nb alloy were successfully fabricated. It is the first time that porous samples of this alloy are obtained by freeze-drying and partial sintering. The SMA powder was initially mixed with deionized water, citric acid, and poly(vinyl alcohol). After freezing the prepared suspensions on a cold finger, the as-obtained ice crystals were removed by freeze-drying. The green bodies were subsequently heat-treated at 980 degrees C for 6 h and quenched to room temperature under argon flow. beta 1' martensite was the major phase observed in the fabricated scaffolds. It was observed that both the structural properties and damping capacity of the obtained samples depend on the size of the particles used for preparing them. The prepared scaffolds showed interesting damping properties in the martensitic field, which could allow their use in high-temperature applications. (C) 2020 Published by Elsevier B.V. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-ne-nd/4.0/).
10.1016-j.jmrt.2020.02.001	-1		The recrystallization process of Cu-30Zn brass during friction stir welding (FSW) was investigated. The microstructural evolution in the stirring period and the subsequent normal air-cooling period were separately studied by using stop-action technology, liquid nitrogen cooling, and subsequent heat treatment. During the stirring period, the initial large grains in the base material underwent serious shear deformation at elevated temperatures, resulting in the occurrence of dynamic recrystallization. The weld exhibited ultrafine grains with high dislocation density and a typical {111}<110> shear texture. The grain refinement mechanism was mainly attributed to discontinuous dynamic recrystallization, although several features of continuous dynamic recrystallization could also be found. In the subsequent normal air-cooling period, static restoration occurred and led to dislocation annihilation, selected grain growth, and appearance of annealing twins. The {111}<110> textural component partially changed into a {110}<001> Goss recrystallization texture. From these results, it was deduced that the brass experienced static restoration following dynamic recrystallization during FSW. The static restoration produced by the stirring remarkably influenced the microstructure. This study concluded that if the rapid cooling method is adopted during FSW, the static restoration process can be effectively restrained, and the microstructure of the joint can be significantly improved. (C) 2020 The Authors. Published by Elsevier B.V.
10.1016-j.jmrt.2020.03.051	15	aging; strength; conductivity; electrical conductivity; electrical; mpa; treatment; strengthening; degrees; cu-; cold; precipitation; tensile strength; tensile; iacs	The evolution and strengthening effect of nanoscale precipitates of the aged Cu-Mg-Fe-Sn-P-Y alloy were investigated via aging treatment in the 400-480 degrees C temperature range and the 10-480 min aging time range. Nanoscale gamma-Fe particles uniformly distributed in the matrix caused dispersion strengthening in the peak-aging stage and transformed to alpha-Fe at the over-aging stage. The Mg3P2 secondary phase hindered the appearance of coarse Fe3P and formed definite orientation relationship (OR) of cubic to cubic with the Cu matrix after 480 min aging, < 110 >(Cu)parallel to < 110 >(Mg3P2), (002)(Cu)parallel to(008)(Mg3P2). The optimal aging parameter for the Cu-Mg-Fe-Sn-P-Y alloy is 60% cold deformation and aged at 460 degrees C for 20 min. The corresponding tensile strength is 599 MPa with the conductivity of 71.1%IACS and the elongation of 6.9%. Compared with the current contact wire, the ultimate tensile strength and conductivity of the studied alloy increased by 20% and 15%, respectively. (C) 2020 The Authors. Published by Elsevier B.V.
10.1016-j.jmrt.2020.07.002	4	transformation; martensite; martensitic; phase; shape; beta; memory; shape memory; temperature; temperatures; martensitic transformation; gamma; transformation temperatures; effect; thermal	To offer a response to the increasing interest on high-temperature shape memory alloys, mainly driven by the aeronautic and aerospace industries, the design and characterization of Cu-Al-Ni shape memory alloys with high transformation temperatures, between 373 K and 473 K, are approached. The present alloy design is based on the transformation from cubic beta(3) austenite to the monoclinic beta'(3) martensite, which offers the advantage of exhibiting not only higher transformation temperatures but also a thermal hysteresis of about 12 K, much smaller than the orthorhombic gamma'(3) martensite historically considered for this alloy system. The influence of the alloy concentration and the thermal treatments, on the martensitic transformation temperatures is systematically analyzed and a quantitative and predictive equation is proposed. The influence of the stress on the transformation was also studied under two experimental conditions: at constant stress as a function of temperature (shape memory effect) and at constant temperature as a function of the stress (superelastic effect). A double stress-induced transformation from beta(3) to beta'(3) and alpha'(3) with an outstanding reversible and reproducible 24% superelastic strain is also reported. The experimental results allows also determine the Clausius-Clapeyron diagrams for this series of alloys, as a fundamental tool for further design of sensing and actuating devices based on these high-temperature shape memory alloys. (C) 2020 The Authors. Published by Elsevier B.V.
10.1016-j.jmrt.2020.08.060	-1		Preexisting twin boundaries (TBs) and deformation twinning have been reported to significantly improve the strength and ductility of nanocrystalline and ultrafine-grained face-centered cubic (FCC) metals and alloys by interaction between gliding dislocations and TBs. Here, we prepared nanocrystalline Cu-30% Zn alloy with an average size of 80 nm and characterized TB-dislocation interactions by high resolution transmission electron microscopy. Our observations show that the TBs with one or multiple (1 1 1) atomic layer steps were formed either by Shockley partial dislocations slipping along TBs or by reversible reaction between unit dislocations and TBs with the help of sessile Frank partial dislocation dissociation. Moreover, dislocation accumulation at the end of twin lamellae form an asymmetric tilt grain boundary in the matrix and prevent twin propagation. Our findings provide insight into understanding TB migration and strengthening mechanisms in highly twinned FCC metals and alloys. (C) 2020 The Author(s). Published by Elsevier B.V.
10.1016-j.jmrt.2020.09.047	5	materials; thermal; heat; properties; material; welding; sintering; fusion; strength; laser; heat sink; thermal conductivity; mechanical; sink; manufacturing	Composition modification (elemental modification) is found to be an effective method for tuning the bimodal microstructure (equiaxed and column grains) observed in the selective laser melted (SLM) metallic materials, and thereby improving their properties. However, optimization for the powder composition is a tedious task consuming energy, time and resources. One of the non-equilibrium processes, melting spinning (MS), matches the solidification conditions of the SLM process (especially the cooling rate), which offers the possibility of using the MS process as the first step in optimizing the elements/alloy design and development for the SLM process. In this work, SLM and MS processes were employed to fabricate the Cu-Ni-Sn alloy to compare the microstructural features and the resultant properties. The result reveals that the sample fabricated by MS shows a similar supersaturated structure as the SLM counterpart and both these samples exhibit analogous microstructure consisting of fine equiaxed grains, column grains, intragranular and intergranular gamma-(CuxNi1-x)(3)Sn phase. The results confirm the possibility of using the MS process as the first step in the alloy design/development for the SLM process. (C) 2020 The Authors. Published by Elsevier B.V.
10.1016-j.jmrt.2020.09.077	16	wear; composite; composites; powders; milling; particles; powder; wt; sliding; friction; hardness; matrix; mechanical; surface; properties	Wettability between Cu and Al2O3 nanoparticles is relatively low, which limit the applicability of this nanocomposite. To this end, electro-less deposition of Ag over Al2O3 nanoparticles were applied to improve their wettability with Cu matrix. Al2O3 coated Ag were mixed with commercially pure Cu powder in varying weight percentages (0, 2, 4, 6 and 8) and then nanocomposites were synthesized through powder metallurgy route. To obtain uniform distribution of nanoparticles in Cu matrix, mixing was carried out via mechanical alloying. Microstructure, mechanical and wear behaviors were investigated to see the effect of Al2O3 nanoparticles content in Cu. The result showed that Al2O3 nanoparticles are homogenously dispersed in the Cu matrix. The hardness and compressive strength were improved by the addition of nanoparticles up to 8 wt%. Around 30% improvement was found in the strength of the nanocomposite. Furthermore, the average hardness of the composite coatings varies from 65.2 to 150 HV as Al2O3 content increases from 0 to 8 wt%. Abrasive wear analysis showed that the abrasive wear resistance of the nanocomposites improves with the increment of nanoparticle content. The microstructure refines due to Al2O3 addendums illustrated a considerable function in the wear behavior of the Cu matrix. Published by Elsevier B.V.
10.1016-j.jmrt.2020.11.049	-1		Phase morphology and the distribution of the strengthening phase generally have a strong influence on the movement of dislocations. The presence of minor alloying element Mg in Cu-30Fe alloy significantly affects both the morphology and distribution of the strength-ening phase. Dendritic a-Fe is transformed into a spherical morphology because of changes in the chemical composition during the solidification process. The presence of Mg leads to the formation of secondary phase-separated Cu within the alpha-Fe phase and to increasing heterogeneity of the gradient size of the alpha-Fe phase. The increased volume fraction of alpha-Fe enhanced by secondary separated Cu, refinement of alpha-Fe, and the degree of distribution enhanced the yield strength of this alloy by 40% compared with that of Cu-30Fe. This result can be used as a guide to modifying the morphology of Cu-Fe alloys and improve understanding of strengthening mechanism of this system. (C) 2020 The Authors. Published by Elsevier B.V.
10.1016-j.jmrt.2020.11.058	-1		For the first time, the origin of tool composition effect on microstructure and mechanical properties of the friction stir welded joints has been disclosed. For this aim, nanoindentation, orientation image microscopy, and transmission electron microscopy were employed to analyze the microstructure and mechanical properties in the case of copperzinc alloy joints welded by different tool compositions. The results showed that the nanosized intermetallic compounds were formed in the stir zone when using a hot-work steel tool, which increased the strength of the joint. The outcomes of this work can be used to modify the friction stir welded joints of various metals and alloys. (C) 2020 The Author(s). Published by Elsevier B.V.
10.1016-j.jmrt.2021.01.045	-1		Graphene was ball-milled with copper powder to acquire copper-graphene (CuG) powder. One and two percent of CuG in weight were added to stacking layers of fully annealed copper sheets and processed using 2, 4 and 6 cycles of accumulative roll bonding (ARB), leading to 2 mm thick copper-graphene nanocomposites with 20, 80 and 320 layers. With respect to the initially annealed copper sheet, the strength of the nanocomposites increased to the cost of significant loss in ductility. Reduced ductility was attributed to the low bonding quality in the form of existence of voids and the graphene chemistry which resulted in delamination and decohesion of the stacking sheets forming the nano composite during tensile tests. After 2 and 4 cycles of ARB, the electrical resistivity was increased which was attributed to the high density of defects and dislocations in addition to poor bonding between the stacking layers of the nanocomposite. Reduced electrical resistivity was achieved after 6 cycles of ARB which can be an indication of the improvement of the bonding at the interface of the nanoparticles with the matrix in addition to the reduction in voids at the interfaces of the stacking layers of sheets. Comparison between the nanocomposites with similarly fabricated multilayer sheets with no graphene addition indicated reduction in resistivity which demonstrates the positive effects of graphene on reducing resistivity. Mechanical strength, ductility and electrical resistivity were found to improve in the nanocomposite with 2% of CuG addition which was followed by further reduction in resistivity by full annealing. (c) 2021 The Authors. Published by Elsevier B.V. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/). Graphene was ball-milled with copper powder to acquire copper-graphene (CuG) powder. One and two percent of CuG in weight were added to stacking layers of fully annealed copper sheets and processed using 2, 4 and 6 cycles of accumulative roll bonding (ARB), leading to 2 mm thick copper-graphene nanocomposites with 20, 80 and 320 layers. With respect to the initially annealed copper sheet, the strength of the nanocomposites increased to the cost of significant loss in ductility. Reduced ductility was attributed to the low bonding quality in the form of existence of voids and the graphene chemistry which resulted in delamination and decohesion of the stacking sheets forming the nanocomposite during tensile tests. After 2 and 4 cycles of ARB, the electrical resistivity was increased which was attributed to the high density of defects and dislocations in addition to poor bonding between the stacking layers of the nanocomposite. Reduced electrical resistivity was achieved after 6 cycles of ARB which can be an indication of the improvement of the bonding at the interface of the nanoparticles with the matrix in addition to the reduction in voids at the interfaces of the stacking layers of sheets. Comparison between the nanocomposites with similarly fabricated multilayer sheets with no graphene addition indicated reduction in resistivity which demonstrates the positive effects of graphene on reducing resistivity. Mechanical strength, ductility and electrical resistivity were found to improve in the nanocomposite with 2% of CuG addition which was followed by further reduction in resistivity by full annealing.
10.1016-j.jmrt.2021.03.073	-1		Initial powder mixtures of Cu, Fe and Co are exposed to severe plastic deformation by high-pressure torsion to prepare solid solutions. A broad range of compositions is investigated, whereas this study aims at the synthesis of soft magnetic materials and therefore at the formation of a homogeneous and nanocrystalline microstructure. For intermediate ferro-magnetic contents, high-pressure torsion at room temperature yields single-phase supersaturated solid solutions. For higher ferromagnetic contents, two consecutive steps of high-pressure torsion deformation at different temperatures yield the desired nanocrystalline microstructure. Depending on the Co-to-Fe-ratio, either a single-phase supersaturated solid solution or a nanocomposite forms. The composite exhibits an enhanced magnetic moment, indicating the formation of a (Fe,Co)-alloy upon severe plastic deformation. Soft magnetic properties are verified for large Co-to-Fe-ratios and this microstructure is found to remain stable up to 400 degrees C. (C) 2021 The Author(s). Published by Elsevier B.V.
10.1016-j.jmrt.2021.03.098	-1		The correlation of the thermomechanical parameters and chemical composition, which enables to determine the phases providing properties related to reliable, recoverable strain, was studied for three Cu-(21.6-25.4)Zn-(3.3-5.6)Al alloys. The conventionally cast samples were hot forged and cold-rolled, followed by quenching in different media and aging treatment. The alloy A with low aluminum content (3.3%) has exhibited better tensile strength and elongation than B and C samples, in addition to good low-temperature workability and refined grain. The stress plateau recorded on the stressestrain curve during tensile testing of quenched specimens was related to the recoverable strain of up to 4.2%. Most of the examined specimens have shown shape memory recovery above 90%. The apparent activation energy for microhardness increase in the examined alloys during aging at 200 degrees C-500 degrees C for up to 30 h was (55.3 +/- 3.9) kJ mol(-1) compared with (55.7 +/- 4.6) kJ mol(-1), which was recorded for the decrease in shape memory recovery. These results suggest a common origin for both changes. The precipitate was formed along the grain boundaries and the matrix. Neither the coarsening of alpha-precipitate nor gamma-precipitate was observed during the aging of examined alloys for up to 30 h . Martensite stabilization was avoided in A and B alloys as a result of the step quenching treatment. A relatively short life expectancy was predicted for alloy C, while good shape memory properties may be expected for alloys A and B during their exposure to temperature up to 50 degrees C. (C) 2021 The Author(s). Published by Elsevier B.V.
10.1016-j.jmrt.2021.05.085	-1		The separation of Cu from the CuxO-FexO containing waste (such as copper slag and electroplating sludge) is always intractable by using pyrometallurgy method. The carbothermic reduction methods, as well as the conventional sulfurization technology by using sulfurization agent FeS2, will introduce lots of iron into the prepared Cu-Fe alloy or Cu-Fe-S matte, and this results in the difficulty in further separation of Cu from Fe. In this work, CaS is utilized as the new sulfurization agent, and the iron content of prepared Cu-Fe-S matte is lower than 5%, while the copper grade is improved to about 76-79%. Such products could be used as the raw materials for producing metallic copper. According to the experimental results, at 1450 degrees C, the copper oxides in CuO-Fe2O3-SiO2-CaO system is selectively sulfurized by CaS, and Cu2S dominated product is formed and separated from slags. The recovery extent of copper reaches 98% when the CaS addition is 1.15 times (1.15CaS) of the stoichiometric quantity required. However, the increase of CaS addition (1.6CaS) will lead to the sulfurization of iron oxides, and make the iron content in Cu-Fe-S matte increase to 15%. Besides, when the Cu/Fe ratio (in mass) of synthetic waste is 0.5, part of the CaS is oxidized by Fe2O3, which results in the recovery extent of Cu to only about 73.30%. However, the copper recovery extent could be improved to 97% by adding extra reductant carbon. (C) 2021 The Author(s). Published by Elsevier B.V.
10.1016-j.jmrt.2021.06.045	-1		The microstructure and kinetics of discontinuous precipitation in Cu-3.2Ti-0.2Fe-xV (x = 0, 0.1, 0.2 and 0.3 wt%) alloys aged at 723, 773, 823 and 873 K were studied by using optical microscopy (OM), scanning electron microscopy (SEM), transmission electron microscopy (TEM) and energy dispersive spectrometer (EDS), with the help of CALculation of PHAse Diagram (CALPHAD) method and Johnson-Mehl-Avrami-Kolmogorov (JMAK) equation. The volume fraction of Laves_C14 was increased with raising V content, leading to the effective grain refinement during casting and the inhibiting grain growth in solution treatment process. The activation energies of Cu-3.2Ti-0.2Fe-xV (x = 0, 0.1, 0.2 and 0.3 wt%) alloys were 196.4, 172.9, 147.4, 154.1 kJ mo1(-1), respectively. The discontinuous precipitation was promoted and controlled by grain boundary diffusion in the early stages at low temperature, while it was inhibited by bulk diffusion at high temperature or in the later stages at low temperature. In addition, the peak-aged hardness was improved with proper amount of V addition due to the strengthening of Laves_C14 and grain refinement, as well as the inhibition of discontinuous precipitation. (C) 2021 The Author(s). Published by Elsevier B.V.
10.1016-j.jmrt.2021.07.020	-1		The present work investigates the Zr-containing precipitate evolution and its effect on the mechanical properties of a CueCreZr alloy after solution treatment at 1253 K for 2 h and aging at 763 K for 0-6 h . The results show that the precipitation sequence of the Zrcontaining precipitates in the CueCreZr alloy is supersaturated solid solution/Zr-rich atomic clusters -> Cu5Zr phase. Zr atoms first segregate at the {111} crystal plane of the copper and form coherent Zr-rich atomic clusters during the aging process, which are composed of Zr-rich atoms monolayers and exhibit plate-shaped. Some of the Zr- rich atomic clusters is transformed into the more stable phase of Cu5Zr phase as the aging time increases, the habit plane of which is the {111}(Cu) crystal plane. The contribution of Zrrich atomic clusters and Cu5Zr precipitates to the yield strength of the alloy is calculated by coherency strengthening and Orowan strengthening, respectively. The total yield strength is very close to the experimentally measured strength . (C) 2021 The Authors. Published by Elsevier B.V.
10.1016-j.jmrt.2021.07.027	4	transformation; martensite; martensitic; phase; shape; beta; memory; shape memory; temperature; temperatures; martensitic transformation; gamma; transformation temperatures; effect; thermal	In this study, the effect of addition of manganese to the ternary Cu-Al-Be shape memory alloys on phase stability, phase transformation temperatures, microstructure, morphology and grain size has been investigated. Secondly, the effect of betatization temperatures and time period has been investigated on the phases and properties of Cu-Al-Be-Mn SMAs. Results reveal that the addition of manganese in the alloys with Al >= 11.8 wt% forms coexistence of beta' (1) and gamma'(1) martensites, and manganese >= 1 wt% forms austenite b1 (DO3). DSC studies exhibit two stage reverse transformation attributes to coexistence of martensites. Increase in manganese decreases the transformation temperatures and increase in betatization temperature and time increases transformation temperatures. Alloying manganese didn't exhibit significant grain refinement and results reduced shape recovery due to the coexistence of martensites. (C) 2021 The Author(s). Published by Elsevier B.V.
10.1016-j.jmrt.2021.10.031	-1		Cu-Al-Mn-Ti-xTa alloys (x =0, 1, 2, 3, wt%) prepared by spark plasma sintering were investigated for the effect of Ta content on the microstructure, mechanical and damping properties. The microstructure and phase composition indicate that the alloy is mainly composed of beta'(1) martensite, gamma'(1) martensite, Ti-rich and Ta-rich phase. As the Ta content increases, the grain size of the alloy first decreases and then increases. The reverse trend was observed for hardness, tensile and compressive strength . The hardness, tensile strength and compressive strength increased by 18.2%, 44.9% and 28%, respectively, when the Ta content was 1 wt% compared to the alloy without Ta element. The presence of martensite provides the alloy with promising damping properties. Meanwhile, the for-mation of the second phase has a two-sided effect on the damping characteristics. That is, the increase in grain boundaries provides more interfaces for energy dissipation, but the increased compressive stress between the interfaces also hinders the movement of the interfaces. Excellent damping performance is demonstrated with the addition of 1 wt% of Ta element. The peak values of damping capacity at room temperature and at about 580 degrees C reached 0.026 and 0.19, respectively. The results confirm that the addition of Ta elements is achievable to obtain Cu-Al-Mn-Ti alloys with both high mechanical and damping properties. (C) 2021 The Author(s). Published by Elsevier B.V.
10.1016-j.jmrt.2021.10.040	3	sma; shape; shape memory; memory; smas; superelastic; bars; damping; cu-al-mn; mechanical; bending; applications; numerical; sma bars; material	Cu-Al-Ni shape memory alloys (SMAs) have high thermal stability and various potential applications. The most significant factors limiting their application are their relatively low elastic strain and poor shape memory effect known as recoverable strain. In addition, the incorporation of new elements for reinforcement usually results in a polycrystalline structure with a larger grain size, which is not suitable for shape memory applications. To overcome these drawbacks, a new method is introduced in this study to increase the shape memory effect and its stability in Cu-Al-Ni SMAs through partial reinforcement with alumina (Al2O3) by selective laser melting. In this approach, the reinforcing lines are deposited in-plane at the mid-height of the printed part, i.e., in the neutral plane. To characterize the effect of partial reinforcement, partially reinforced parts with 0.3 wt% and 0.9 wt% Al2O3 are compared to fully reinforced parts. The results show that the accumulation of localized residual compressive stresses above the reinforcing lines in the neutral plane, induced during selective laser melting, increases the shape memory effect as a result of the increase in mechanical anisotropy in the building direction. Moreover, a new phenomenon named the waistband effect is observed in cyclic compressive operation, which results in incremental penetration of the reinforcing particles into the neutral plane during compression. This facilitates a higher strain recovery in the partially reinforced part. These results clearly confirm that partial reinforcement with Al2O3 significantly enhances the shape memory effect of Cu-Al-Ni SMAs. (C) 2021 The Authors. Published by Elsevier B.V.
10.1016-j.jmrt.2021.10.044	0	solidification; phase; magnetic; magnetic field; undercooling; field; liquid; separation; peritectic; immiscible; cu-; dendrite; phase separation; microstructure; primary	In order to replace toxic Cu-Pb bearing alloy, a novel strategy to design and produce new environment-friendly Cu-Bi bearing alloy was proposed with the guidance of thermodynamic analysis and CALPHAD. It's found that alloying element Sn can slow down the nucleation of alpha-Cu and introduce a (alpha-Cu + L-1 + L-2) three-phase-coexistence state in Cu-Bi -Sn ternary system by weakening the separation between elements Cu and Bi. Pseudobinary phase diagrams of the Cu-Bi-xSn (wt%, x = 0, 2, 4, 6) systems were calculated through CALPHAD, and a (alpha-Cu + L-1 + L-2) phase region was found in Cu-Bi-6Sn phase diagram. Based on the above phase diagrams, the Cu-24Bi-xSn (wt%, x = 0, 2, 4, 6) alloys were prepared. Bi-rich minor phase particles (MPPs) show continuously network morphology in Cu-24Bi-(0, 2, 4) alloy, and show independently rod-like morphology in Cu -24Bi-6Sn alloy. It's thus revealed that (alpha-Cu + L-1 + L-2) state introduced by alloying element Sn can effectively promote the MPPs transforming from network to rod-like morphology. Simultaneously, it's found that the friction coefficients the Cu-24Bi-xSn alloys decrease from 0.236 in Cu-24Bi to 0.182 in Cu-24Bi-6Sn. It's indicated that the self-lubricating property of the Cu-24Bi-xSn alloys will be increased with Sn content increasing from 0 wt% to 6 wt%. Cu-24Bi-6Sn alloy is thus identified to be the alloy with the best microstructure and self-lubricating property. (C) 2021 The Author(s). Published by Elsevier B.V.
10.1016-j.jmrt.2021.11.114	-1		Copper matrix composites (CMC) are frequently used in the automotive, aerospace, construction, and electrical-electronics industries. Properties such as low density, improved fatigue strength, high hardness, and high specific strength are the factors that make copper matrix composites important. The development of these factors is important for the industrial use of copper matrix composites. SiCp doped metal matrix composites have better mechanical properties than pure alloys. It is also known that Ti, B powder particle additives improve the mechanical properties of the main matrix. In this study, Cu hybrid composites reinforced with Ti-B-SiCp powders, which were not produced before, were obtained and their microstructure, density, hardness, and wear behavior were investigated. Composite materials produced by powder metallurgy method were prepared at 2-8 wt. % mixing ratios. Then each material was sintered at temperatures of 950-100-1050 degrees C. Microstructural images showed homogenous distribution in the composite material. The highest relative density of 93% was obtained in the composite material with a 2% reinforcement rate at 1050 degrees C. It was found that the hardness increased with the increase of the reinforcement rate up to 6 wt% and then decreased after that. It was observed that the specific wear rate increased with the increasing reinforcement ratio. In addition, the lowest friction coefficient and wear temperature occurred at a sintering temperature of 1050 degrees C. In this study, it was reported that the sinter temperature value of 1050 degrees C is the optimum temperature value in terms of the tribological and mechanical performance of the materials. (C) 2021 The Authors. Published by Elsevier B.V.
10.1016-j.jmrt.2021.12.027	2	corrosion; surface; film; electrochemical; films; spectroscopy; layer; current; solution; potential; resistance; composition; x-ray; ions; showed	The present study reports the glass-forming ability, density change on crystallization and corrosion behavior of newly developed rare-earth free Cu-based metallic glasses (CBMGs). The critical casting thickness of these new CBMGs increased from 15 mm at 8 at% Hf to 22 mm at 12 at% Hf, reaching a maximum value of 28.5 mm at 13.5 at% Hf. It dropped to 24 mm and 15 mm thereafter, for 15 and 20 at% Hf, respectively. The alloys showed a monotonic increase in density going from 8 at% Hf to 20 at% Hf, with the density of amorphous samples increasing from 7.83 g/cm(3) to 8.84 g/cm(3) and crystallized samples increasing from 7.92 g/cm(3) to 8.91 g/cm(3). Potentiodynamic polarization tests carried out in 0.1, 0.2 and 0.5 M NaCl solution at 25 degrees C showed a direct correlation between corrosion resistance and Hf content in the order: 8 at% < 13.5 at% < 20 at% Hf. Increase in NaCl concentration also had a significant impact on the corrosion intensity due to the chaotropic effect. Scanning electron microscopy of corroded sample surfaces showed formation and eventual merging of individual micro cracks resulting in a mud-cracking pattern. Energy dispersive X-ray spectroscopy maps of pitted regions revealed reduction in Zr and Al concentration with increase in Hf and Cu percentage for all compositions. An increase in the O concentration along with the appearance of new peaks in the X-ray photoelectron spectroscopy results, measured post corrosion, confirmed the formation of metal oxides and oxyhydroxides in the passive layer. (c) 2021 The Authors. Published by Elsevier B.V. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/).
10.1016-j.jmrt.2021.12.063	16	wear; composite; composites; powders; milling; particles; powder; wt; sliding; friction; hardness; matrix; mechanical; surface; properties	Ceramics-based composites are a special class of materials carrying combined properties that belongs to alloys and metals according to market demands. This makes composites completely different and paves the way for new applications that requires the utmost properties. Machining of such composites is of great importance to finalize the fabrication process with improved part quality; however, the process implies several challenges due to the complexity of the cutting processes and random material structure. The current study aims to examine the machinability characteristics when milling novel material, Cu-B-CrC composites using Al/TiN coated carbide tools. Further, the influence of machining parameters along with the different weight ratios of the powders amounts used to fabricate the machined reinforced samples on output parameters namely surface roughness, tool wear, chip morphology and cutting temperatures was investigated. One of the key findings of the study is the dominant effect of reinforcement ratio (Cu, B, CrC) on machinability, which showed that 5% additive (2% B, 3% CrC) provides improved properties such as surface roughness, tool wear and cutting temperature. Cutting speed alterations play an important role in the machinability characteristics, i.e., increasing value increases flank wear and cutting temperatures and reduces surface roughness. Increasing feed rate in-creases the surface roughness meanwhile its effect shows changing behavior on the flank wear and cutting temperatures according to cutting speed and reinforcement ratio.(c) 2021 The Authors. Published by Elsevier B.V. This is an open access article under the CC BY license (http://creativecommons.org/licenses/by/4.0/).
10.1016-j.jmrt.2021.12.129	16	wear; composite; composites; powders; milling; particles; powder; wt; sliding; friction; hardness; matrix; mechanical; surface; properties	In this study, laser surface alloying of commercially pure copper (cp Cu) with Cr/Ti and Cr/Ti/CNT was conducted using a high-power diode laser. Cu-Ti intermetallic phases were detected in the Cu/Cr matrix of the laser-alloyed specimens without CNT. While TiC was found in the Cu/Cr matrix of the laser-alloyed layers with CNT. Compared to cp Cu (60 +/- 10 HV0.2), the laser-alloyed specimens without and with CNT could achieve hardness up to 423 +/- 12 HV0.2 and 860 +/- 24 HV0.2 respectively. Sliding wear tests were also carried out at 60 km/h in dry condition with a pin-on-disc tribometer. Compared with cp Cu, the wear resistances of all laser-alloyed specimens were significantly improved due to solid solution alloying, existence of harder phases including Cr, Cu-Ti intermetallics and TiC. The wear resistance of the laser-alloyed specimens was increased up to a factor of 1220 times as compared with cp Cu. For the polarization study, the corrosion current densities of all laser-alloyed specimens (0.164-0.275 mu A/cm(2)) in 3.5% NaCl solution at 25 degrees C were found to be lower than that of copper (3.362 mu A/cm(2)) due to presence of passive Cr and Ti. (C) 2021 The Author(s). Published by Elsevier B.V.
10.1016-j.jmrt.2022.01.026	10	composites; nanoparticles; strength; matrix; high; strengthening; particles; conductivity; composite; electrical; mpa; sintering; ods; grains; mechanical	A homogeneously ultrafine-grained (UFG) Cu-38 Zn alloy with an average grain size of 0.64 mu m is successfully fabricated by equal channel angular processing (ECAP), which exhibits a significantly enhanced strength-ductility synergy. The strength enhancement can be attributed to grain refinement and dislocation strengthening. After annealing the ECAP processed alloy at 300 degrees C for 30 min, a further enhanced strength with almost unchanged ductility was achieved. This unusual annealing strengthens is associated with the solute/impurity segregation and precipitations inside the grains. (c) 2022 The Authors. Published by Elsevier B.V.
10.1016-j.jmrt.2022.01.075	-1		The D0(22) or L1(2) -gamma'& nbsp;phase strengthened Cu-Ni-Sn alloys possesses a characteristic microstructure, exhibiting the distribution of precipitated phase with smaller size on a spinodal decomposition structure, which leads to that the composition of the precipitated phase and Cu matrix cannot be precisely measured and restriction of the accurate compositional design of the alloys. The present work initials to introduce the cluster plus-glue-atom model for compositional interpretation of the industrial Cu-Ni-Sn alloys, and then optimizing the cluster formula according to the measured composition of the relevant precipitated phases. Moreover, the solid solution content of Ni or the precipitation content of Sn are calculated based on the optimized cluster formula, and establishing the relationship between the alloy composition and properties. It indicates that the strength mainly relays on the precipitation content of Sn while the conductivity depends on the solid solution content of Ni, which is also suitable for the Cu-Ni-Sn-Zn (Co) alloys or Cu-Ni-Al alloys with similar characteristics. Additionally, the ratio of strength/resistivity increases in the alloys as the increasing Sn content under the premise of close to 3 of Ni/Sn (or (Ni thorn Co)/Sn) atomic ratio, but the discontinuous precipitation is easily to generate. Therefore, the improved properties of the alloys cannot be attained via the reducing ratio of Ni/Sn (or (Ni thorn Co)/Sn) atomic ratio solely. Based on the above, this work provides theoretical support and application methods for the compositional design and performance prediction of coherent D022 or L1(2) -gamma'phase strengthened alloys.(C) 2022 The Author(s). Published by Elsevier B.V.& nbsp;
10.1016-j.jmrt.2022.03.020	-1		A series of novel Cu-2Ag-xLa alloys with reinforced mechanical properties and enhanced electrical conductivities are developed. The effects of La addition on the microstructural features and mechanical properties of as-cast and solution treated Cu-2Ag alloys are systematically investigated. The yielding strength of as-cast Cu-2Ag alloys with 0.02La and 0.07La (wt%) is considerably reinforced by relative amounts of 55.56% and 30.16%, respectively. The strengthening mechanism for such increased yielding strength is mainly related to the shifting of interfacial relation between matrix and Ag-rich phase from original semicoherent type to non-coherent type with La doping. Consequently, the interface barrier strength is enhanced by the non-coherent interface, and contributes to the increased yielding strength . Meanwhile, the strengthening effect from La addition closely depends on the exact contents of La element. As La content increases from 0.02 to 0.07 (wt%), the strengthening effect becomes weaker because of the increased space of Ag-rich phases leading to an 16.33% decrease in yield strength . Additionally, La has dual effects on the dissolution of Ag-rich phases and precipitation of new La-rich phase in the as-cast alloys during solution treatment. Simultaneously, the precipitation of the La-rich phase abnormally enhances the electrical conductivity of the solution La-containing alloys when the solution time exceeds 24 h . (C) 2022 The Author(s). Published by Elsevier B.V.
10.1016-j.jmrt.2022.05.027	6	grain; deformation; strain; strength; dislocation; cu-; tensile; size; ecap; grain size; sfe; ductility; hardening; high; stress	Nanocrystallization can significantly improve the strength and hardness of metallic materials, but usually sacrifice ductility due to low work hardening capability. Heterostructured materials are an emerging class of materials with superior performances, because of their outstanding work hardening capability. In this work, a type of heterostructured material, a gradient structured Cu-Al alloy, was produced by surface mechanical attrition treatment (SMAT) at liquid nitrogen temperature. After SMAT processing, the yield strength was increased to more than 1.5 times, and the ductility remained almost unchanged. In conjunction with hetero-deformation induced (HDI) hardening, stacking fault energy is another important factor to increase the strain hardening in the system. Low stacking fault energy increased the density of stacking fault, and led to a finer spacing of nano twins (similar to 5.4 nm) and higher dislocation storage (8 x 10(13) m(-2)) in the SMATed Cu-Al alloy at the intermediate strain stage. A significant up-turn of strain-hardening rate was also induced by low stacking fault energy. (C) 2022 The Author(s). Published by Elsevier B.V.
10.1016-j.jmrt.2022.05.090	15	aging; strength; conductivity; electrical conductivity; electrical; mpa; treatment; strengthening; degrees; cu-; cold; precipitation; tensile strength; tensile; iacs	The effect of trace B on the properties and microstructure of Cu-Cr-Zr alloy was investigated in this work. Aging precipitation phases in Cu matrix were analyzed by trans-mission electron microscopy (TEM) and high-resolution transmission electron microscopy (HRTEM). It was found that Cr is the main precipitation phase and its precipitation process is affected by B. Boron can increase the precipitation rate of the precipitation phase and promote the precipitation of the precipitation phase. After Cu-Cr-Zr alloy aged at 480 C for 2 h, nanosized Cr particles were coherent with the Cu matrix and formed coherent G.P zones. In Cu-Cr-Zr alloy with 0.03wt% B addition, the aging precipitation process was accelerated, resulting in most of the aging precipitate being bcc Cr. Effect of trace B on hardness and electrical conductivity of Cu-Cr-Zr alloy was tested. It is indicated that B addition improves the hardness and electrical conductivity of the alloy and 0.03wt% B corresponds to the peak value of conductivity and hardness of Cu-Cr-Zr-B alloy. (C) 2022 The Author(s). Published by Elsevier B.V.
10.1016-j.jmrt.2022.06.060	15	aging; strength; conductivity; electrical conductivity; electrical; mpa; treatment; strengthening; degrees; cu-; cold; precipitation; tensile strength; tensile; iacs	With the development trend of connectors to high-current and high-temperature service, copper alloy connectors are required to have superior stress relaxation resistance. In this work, the optimal aging parameter was explored via stress relaxation resistance, strength, microhardness, and conductivity. And the strengthening mechanism of stress relaxation was investigated through the TEM and EBSD microscopic characterization. The results show that the Cu-Cr-Ni alloy reached the peak aging state under 450 degrees C for 1 h and obtained excellent properties. Especially, the percentage of residual stress in the relaxation test reached 93.1%. The microhardness associated with aging strengthening showed a positive correlation with yield strength and stress relaxation resistance. Then the microhardness after aging can be used as a simple evaluation index of stress relaxation resistance. The Cu-Cr-Ni alloy with superior stress relaxation resistance is mainly related to dislocation strengthening, second phase strengthening, and the coexistence of spinodal decomposition and ordering. (c) 2022 The Author(s). Published by Elsevier B.V. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/).
10.1016-j.jmrt.2022.07.091	1	shape; memory; shape memory; damping; martensite; martensitic; damping capacity; transformation; capacity; strain; superelasticity; temperature; cu-al-mn; shape memory effect; effect	In this study, the Cu-11.85Al-3.88Mn-1.6Nb (wt%) shape memory alloy with low cost and a highly functional response was manufactured by selective laser melting(SLM). The effects of energy inputs (123-185J/mm(3)) on their microstructure, mechanical, and shape memory properties were investigated. It was observed that all of the samples were composed of 18R and 2H martensite, and the nanosized (Cu, Mn)(3)Al3Nd4 phase was formed during selective laser melting(SLM). In addition, the good compressive fracture strength and strain were 1652Mpa, and 15.1% respectively. An excellent shape memory effect of 99.26% recovery ratio and 5.32% shape memory strain was obtained by SLM. (c) 2022 The Authors. Published by Elsevier B.V.
10.1016-j.jmrt.2022.07.113	-1		We have monitored the full-stage precipitate evolution in Cu-0.55Cr-0.07Zr alloy during aging at 480 degrees C (753 K) up to 14 days (20160 min), using micro-hardness, positron annihilation spectroscopy, electron microscopy and atom probe tomography. Cr-rich precipitates form during the early stages of aging, and after 5.5 min the distribution is characterised by a number density of 8x10(23) m(-3) and an average precipitate size of 2.5 nm. At that time, Zr segregation is also detected at the precipitate sites. Longer aging times lead to precipitate coarsening, simultaneously with the occurrence of a Zr-rich shell around precipitates potentially to help reduce local coherency strains. Peak aging of the alloy is attained after 120 min of aging, and overaging induces further precipitate coarsening and the transition from spherical to disc-like morphology. At the longest aging time of 14 days, the precipitates maintain a face-centred cubic symmetry, reaching an average size of similar to 9 nm at a density of 0.2 x10(22) m(-3). The presence of Zr atoms at the precipitate site and interface, and the disc-like morphology of overaged precipitates, should be considered when assessing the precipitate stability under irradiation and the precipitate/matrix interface as a potential sink for radiation-induced lattice defects. (C) 2022 The Author(s). Published by Elsevier B.V.
10.1016-j.jmrt.2022.07.131	-1		Oriented SiC whisker-reinforced Al2O3/Cu composites were fabricated by powder metallurgy and hot extrusion. The microstructure of the composites was characterized by scanning electron microscopy. The mechanical properties and electrical conductivity of the composites were measured. The results indicated that the SiC whiskers aligned along the extrusion direction, and the nano Al2O3 particles were uniformly dispersed in the Cu matrix with ideal interfacial bonding. Particle and whisker hybrid reinforcement significantly enhanced the mechanical properties. The yield strength and elongation of (1 vol.% SiCw + Al2O3)/Cu composites were 6% and 15.6% higher than those of the Al2O3/Cu composites, respectively. The experimental yield strength was consistent with the theoretical value associated with different strengthening mechanisms. The main strengthening mechanisms were fine grain strengthening, Orowan strengthening and load transfer strengthening. The electrical conductivity of all the composites was higher than 82.8% IACS; however, the SiC whiskers led to electrical conductivity anisotropy. In general, the electrical conductivity of composites is related to the volume fraction and type of reinforcement. Therefore, the influence of the hybrid composition on the electrical conductivity was studied, and an analytical model for the electrical conductivity of hybrid-reinforced copper matrix composites was established, including the characteristic parameters of the particles and whiskers. The model and presented findings can provide a design basis for hybrid-reinforced composites. (C) 2022 The Author(s). Published by Elsevier B.V.
10.1016-j.jmrt.2022.09.054	15	aging; strength; conductivity; electrical conductivity; electrical; mpa; treatment; strengthening; degrees; cu-; cold; precipitation; tensile strength; tensile; iacs	A Cu-9Ni-6Sn alloy bar with axial columnar grains was prepared by directional solidifica-tion. The effects of aging on the microstructure and mechanical properties of the alloy were studied. The results showed that the alloy had columnar grains oriented along the axis and underwent continuous cold-drawing with a total deformation amount of 85%, a fibrous structure along the axis was formed. For the homogenized alloy, the tensile strength is 385 MPa, the hardness is 80 HV, and the elongation after fracture can reach 38.5%. After aging at 360 degrees C for 120 min, (Cu, Ni)3Sn phase precipitated intermittently along the grain boundary, and the tensile strength and elongation of the alloy were 1057 MPa and 7.1%, respectively. With increasing aging time to 240 min, the number of (Cu, Ni)3Sn phase increased and coarsened obviously, forming a precipitation-free zones, with occurrence of recrystallization of the Cu matrix. The preparation of Cu-9Ni-6Sn alloy billet by directional solidification, combined with large-deformation drawing and aging, is a new method to prepare high performance Cu-9Ni-6Sn alloy wire.(c) 2022 The Author(s). Published by Elsevier B.V. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/).
10.1016-j.jmrt.2022.09.077	-1		Cu/Al laminated composite is a kind of material with wide application value, which has attracted the interest of many researchers. Improving the formability of Cu/Al laminated composite is a hot research topic. Electrically assisted manufacturing technology can improve the formability of metal materials, and its application to Cu/Al laminated com-posite plate is anticipated to improve its formability. In this work, the mechanical prop-erties of Cu/Al laminated composite during electrically assisted (EA) tension were studied, and the effect of electric current on the microstructure evolution of Cu/Al laminated composite was characterized. The results showed that the forming force of Cu/Al lami-nated composite decreased significantly with the increase of current when the frequency is constant, but the forming limit decreased. The reason was that the increase in current density led to local overheating, which eventually led to premature fracture of the spec-imen. Under low frequency conditions, the elongation of Cu/Al laminated composite decreased moderately, but the forming force decreased obviously. The microstructure characterization results showed that the electric current circulated only in the Cu matrix during the EA tension. The electric current lowered the dislocation density of Cu layer and promoted dislocation unwinding. The proportion of recrystallized grains in the Cu layer increased slightly under the action of current. In addition, the current accelerated the change of texture type of Cu layer and the texture strength decreased. (c) 2022 The Authors. Published by Elsevier B.V. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/).
10.1016-j.jmrt.2022.09.103	6	grain; deformation; strain; strength; dislocation; cu-; tensile; size; ecap; grain size; sfe; ductility; hardening; high; stress	Commercially pure copper rod was successfully subjected to severe plastic deformation by applying the continuous equal channel angular pressing (ECAP-Conform) method at room temperature. Microstructural characterizations of copper rod samples at various stages of plastic deformation were carried out by optical microscopy and electron backscatter diffraction methods. X-ray diffractometry and Kernal average misorientation were used for dislocation density estimations. Microstructural evaluations revealed grain size change of 30 mm for the initial annealed copper rod to less than 5 mm and even 100 nm for severely deformed samples. Mechanical behaviors of samples after different deformation stages were characterized using tensile and hardness tests. The ultimate tensile strength of the severely deformed copper rod was increased threefold by ECAP-Conform while elongation halved in comparison to the initial annealed copper. Low-temperature annealing of severely plastic deformed samples led to bi-modal grain size distribution and lowering of strength accompanied by the increase of elongation. Tensile properties of severely deformed and then annealed copper samples showed around a 40% increase in both ultimate tensile strength and elongation in comparison to the initial annealed copper rod. (c) 2022 The Authors. Published by Elsevier B.V.
10.1016-j.jmrt.2022.10.122	-1		Grain boundary (GB) stability and strength are two essential points for nanocrystalline materials. In this study, the effects and underlying mechanisms of segregation-induced GB stabilization and GB strengthening in various Cu GBs for selected 8 alloying elements (Mg, Ca, Cr, Ni, Zn, Zr, Ag and Sn) were investigated through first-principles total energy cal-culations. The segregation energy results show that all other elements excluding Ni can segregate to GB thus improving the GB stability. The segregation driving force is associated with the volume of Voronoi cell of solute, in the trend that increases along with the volume of Voronoi cell growth . The stabilizing mechanism should attribute to the decrease in the number of antibonding electrons. As to GB strength, the embrittling potency results show that Mg, Cr, Zr and Ag are enhancers in S5 [001](310) GB, while for S5 [001](210) and S11 [110](113) GBs, only Cr and Zr are enhancers. The embrittling potency is concerned with segregation energy and the volume of Voronoi cell of solute, in a trend that increases with the segregation energy decline and the volume of Voronoi cell growth . The enhancing mechanism lies in the formation of covalent-like bonds between solute and matrix atoms. Furthermore, by comparing the stabilizing and strengthening effectiveness of alloying el-ements in various Cu GBs. The trend that the worse the stability and strength of GBs, the better the stabilizing and strengthening effects of alloying elements were revealed.(c) 2022 The Author(s). Published by Elsevier B.V. This is an open access article under the CC BY license (http://creativecommons.org/licenses/by/4.0/).
10.1016-j.jmrt.2022.10.130	10	composites; nanoparticles; strength; matrix; high; strengthening; particles; conductivity; composite; electrical; mpa; sintering; ods; grains; mechanical	Advanced Cu-Cr alloys with high strength and thermal conductivity are promising heat dissipation materials but their applications are restricted to low and medium temperatures (<450 degrees C) due to the coarsening of Cr nanoparticles and grain recrystallization. In this study, a Cu-Cr-Y alloy strengthened by nano-Y2O3 dispersion (ODS Cu-Cr-Y alloy) was prepared by mechanical alloying using atomized Cu-Y alloy, Cr and Cu2O as Y source, microalloying element and oxidant material, respectively. The microstructure and high temperature (600 degrees C) properties of ODS Cu-Cr-Y alloy were investigated. It was found Y2O3 nanoparticles with ultrafine particle size (8.35 nm) and high number density (2.16 x 1023/ m3) were distributed homogeneously in Cu matrix and residual Cr particles (50-100 nm) were formed on grain boundaries. The high temperature tensile strength and softening resistance of ODS Cu-Cr-Y alloy far exceeded that of traditional Cu-Cr alloys, which can be attributed to the thermodynamic stability of nano-Y2O3 dispersions and the inhibition of Cr nanoparticle growth by Y addition and residual Cr particles. The ODS Cu-Cr-Y alloy pro-vides an optimal combination of strength and thermal conductivity at high temperature, showing great promises to be used as heat dissipation material under severe conditions like those in fusion plants and rocket engines.(c) 2022 The Author(s). Published by Elsevier B.V. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/).
10.1016-j.jmrt.2022.11.046	15	aging; strength; conductivity; electrical conductivity; electrical; mpa; treatment; strengthening; degrees; cu-; cold; precipitation; tensile strength; tensile; iacs	In this paper, the prepared Cu-0.25Cr alloy and Cu-0.25Cr-0.03Ti alloy strips were treated with aging at 490 degrees C for different holding time. The electrical conductivity and the yield strength of the alloy were tested. The morphology, size, spacing and phase structure of Cr-rich precipitates in the copper matrix were observed by TEM. The results show that the evolution rule of Cr-rich precipitates in Cu-0.25Cr alloy is as follows: supersaturated solid solution->G. P region (Cr atom-rich region)-> Cr-rich precipitates with fcc structure->Cr-rich precipitates with ordered bcc structure. The precipitates of peak aged Cu-0.25Cr alloy consist of fcc Cr-rich precipitates and ordered bcc Cr-rich precipitates. The electrical conductivity and the yield strength is 93.5%IACS and 178 MPa, respectively. The strengthening mechanism is mainly attributed to the synergistic effect of dislocation shear and dislocation bypass. Compared with Cu-0.25Cr alloy, the yield strength of Cu-0.25Cr-0.03Ti alloy at peak aging state increases by 31.5%, while the electrical conductivity re-mains at 82.4%IACS. The great increase in strength is mainly attributed to the refinement of bcc Cr-rich precipitates by adding trace Ti element. The addition of Ti promotes the nucleation of Cr-rich precipitates and refines the Cr-rich precipitates of bcc structure. The interaction mechanism is that there is a strong mutual attraction between Ti and Cr atoms, which promotes the formation of clusters between Ti and Cr. This research results can provide a theoretical basis for the development of copper alloy for high-performance electrical connectors in aerospace, new energy vehicles and other fields.(c) 2022 The Author(s). Published by Elsevier B.V. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/).
10.1016-j.jmrt.2023.01.092	17	wear; composites; coating; friction; composite; coatings; surface; tribological; properties; wear resistance; resistance; powder; sliding; matrix; wear rate	To clarify the influence of process parameters on the microstructure and wear resistance of coating, a series of Ni60 A alloy were deposited on copper surface by plasma cladding under different preheating temperatures. The obtained coatings were new alloy materials formed by the dilution of Ni60 A alloy with Cu, and their microstructure and properties were closely related to the dilution rate. With the increase of preheating temperature, the dilution rate of the coatings increased obviously, which led to a gradual increase of the copper content in the g-(Cu, Fe, Ni) solid solution phase, thus resulting in compositional inhomogeneity and performance deterioration of the coating. From 500 degrees C to 800 degrees C (pre-heating temperature), the average hardness of the coating decreased from 680.3 HV0.1 to 406.6 HV0.1 , and the wear resistance reduced by 2.8 times. The wear mechanism of the coating changed from abrasive wear to the combination of abrasive wear and adhesive wear. For practical applications, to ensure the excellent wear resistance of the coating, the preheating temperature should be controlled at a low level.(c) 2023 The Authors. Published by Elsevier B.V. This is an open access article under the CCBY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/).
10.1016-j.jmrt.2023.02.163	15	aging; strength; conductivity; electrical conductivity; electrical; mpa; treatment; strengthening; degrees; cu-; cold; precipitation; tensile strength; tensile; iacs	Cu-1.3 wt%Ni-1.0 wt%Co-0.9 wt%Si-0.1 wt%Mg alloy strip with 10 mm in thickness produced by heating-cooling combined mold (HCCM) horizontal continuous casting was cold rolled. Microstructure evolution and mechanical properties of the cold-rolled alloy strips with different reduction were studied, and the deformation mechanism was clarified. The results showed that the continuous casting strips had axial columnar grain with main <001> orientations and straight small angle grain boundaries, the elongation after fracture was up to 25.0%, which can be directly processed by large deformation cold rolling, and the maximum cumulative cold deformation was up to 99%.When the reduction was 40% and 60%, the dislocation bands crossed each other and shear bands formed, and the alternating distribution of soft/hard oriented grains were conducive to improve the deformation coordination ability of micro-region under high strain. When the deformation exceeded 80%, deformation twins formed and the twins had strong interaction with the shear band and grain boundaries, resulting in strong shear and rotation of the local grains. The tensile strength and hardness increased from 464 MPa to 137HV of the as-cast strip to 629 MPa and 208HV with reduction 90%, respectively, while the elongation decreased from 25.0% to 4.1%. These results can lay a foundation for the development of compact method for producing high performance Cu-Ni-Co-Si alloy strips. (c) 2023 The Authors. Published by Elsevier B.V. This is an open access article under the CC
10.1016-j.jmrt.2023.02.186	-1		Low-segregation Cu-16Sn-0.3Ti alloy is the key raw material for the preparation of Nb3Sn superconducting wires. In this work, the non-segregation Cu-16Sn-0.3Ti alloy powders were successfully prepared by using vacuum induction melting inert gas atomization (VIGA) method and homogenization treatment in vacuum. The segregated solidification behavior of atomized Cu-16Sn-0.3Ti alloy droplets during gas atomization, the interface segregation and atomic diffusion behavior of alloy powders during homogenization were investigated. The results show that the segregated solidification of atomized droplets oc-curs in the form of twinned spherical segment. A critical morphological transition from cellular to dendritic structure occurs when the powder diameter is in the range of 44.1-86.0 mm. With the decreasing of the powder diameter, the lattice distortion in the a phases increases, and the 8 phase volume fraction decreases. Increasing the cooling rate of atomized Cu-16Sn-0.3Ti alloy droplets is an important measure to limit the segregation of Sn. The homogenization condition of 550 degrees C for 96 h is not only conducive to the disso-lution of 8 phases, but also conducive to inhibiting the significant segregation of 8 phases at the powder boundaries. The results provide guidance for the preparation of low -segregation Cu-16Sn-0.3Ti alloys. (c) 2023 The Author(s). Published by Elsevier B.V. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/).
10.1016-j.jmrt.2023.03.127	-1		By means of direct current electrodeposition, Cu foil with columnar grain growth and equiaxed grain growth with different average grain sizes were prepared. Electron backscatter diffraction (EBSD), X-ray diffraction (XRD), atomic force microscopy (AFM), and transmission electron microscope (TEM) were employed to elucidate the correlation between the microstructures and properties of Cu foil after a certain relaxation time under different grain growth methods. A remarkable preferential ratio of {220} orientation was exhibited in the columnar-grown copper. However, as the copper layer transitions to equiaxed grain growth, the superiority altered to {200} crystal orientation. This variability in grain orientation makes the copper layer profile of columnar crystal growth higher than that of equiaxed crystal formation. The twin boundary density in copper foil increases as the grain growth mode changes from columnar to equiaxed, and grain refinement is beneficial to increase the twin boundary density in the samples. And columnar crystal copper and equiaxed crystal copper show different twin characteristics. There are a few single-stage twin steps in columnar crystal copper and more multi-stage twin steps in equiaxed crystal copper. With an increase of twin boundary density, both the tensile strength and the ductility increase remarkably. (c) 2023 The Authors. Published by Elsevier B.V. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/).
10.1016-j.jmrt.2023.03.164	6	grain; deformation; strain; strength; dislocation; cu-; tensile; size; ecap; grain size; sfe; ductility; hardening; high; stress	In this study, the ultrafine-grained (UFG) Cu-5Mn alloys were prepared by friction stir processing (FSP) to investigate the influence of short-range ordering (SRO) on the tensile deformation behavior. Due to the dynamic recrystallization, the uniform and equiaxed UFG microstructures were obtained in FSP Cu-5Mn alloys with low density of dislocations, high fraction of high-angle grain boundaries, high Taylor factor and high degree of recrystallization. The introduction of Mn atoms into the Cu matrix cannot change the stacking fault energy apparently but increase the SRO degree. Although the dominant mechanism was still the wavy slip of dislocation, the planar slip of dislocations was motivated and many twin layers were observed in the ultrafine grains of FSP Cu-5Mn alloy. The change of SRO degree can significantly improve the dislocation storage capacity during the tensile deformation process, and promote the improvement of the strain-hardening rate, resulting in an excellent strength-ductility match in FSP UFG Cu-5Mn alloy.& COPY; 2023 The Author(s). Published by Elsevier B.V. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/).
10.1016-j.jmrt.2023.04.086	0	solidification; phase; magnetic; magnetic field; undercooling; field; liquid; separation; peritectic; immiscible; cu-; dendrite; phase separation; microstructure; primary	In this study, ternary Cu52Co24Fe24 immiscible alloys are prepared with varying undercoolings and under a high magnetic field. The microstructure evolution and properties of the alloys are investigated. The temperature range of the immiscible gap is determined using CALPHAD. According to the excess Gibbs free energy of liquid, the addition of Fe promotes the demixing tendency of the Cu-Co-Fe ternary system during solidification. With the application of a magnetic field, the (Fe, Co)-rich phases transform from a globular shape to an elongated form along the direction of the magnetic field during solidification, which is due to the existence of the counteracting behavior of the interparticle magnetic dipole-dipole force at the critical droplet size. Under a high magnetic field, the obtained samples had a more dispersed minority phase, higher microhardness and better conductivity. However, the saturation magnetization of the samples with large undercooling decreases with increasing magnetic field due to the suppression of the phase separation behavior under a high magnetic field. This study proposes a novel technology for preparing immiscible alloys with excellent properties by applying a superimposed magnetic field during solidification.& COPY; 2023 The Author(s). Published by Elsevier B.V.This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/).
10.1016-j.jmrt.2023.04.177	0	solidification; phase; magnetic; magnetic field; undercooling; field; liquid; separation; peritectic; immiscible; cu-; dendrite; phase separation; microstructure; primary	Applying cycle superheating and molten glass purification technologies, Cu60Ni35Co5 alloys were deeply undercooled to maximum undercoolings of 284 K. The microstructure characteristics and its evolution varying with bulk undercooling during the rapidly solidified process were analyzed. It was found that, after minor addition of element Co, crystal refinement mechanisms of the undercooled Cu60Ni35Co5 system was similar to those of the Cu-Ni sytem. Crystal refined microstructure appearing at the low undercoolings was result of dendrite remelting mechanism; the dominant factor of grain refinement microstructure appearing at high undercooling regime was resultant from the recrystallization process. Driving force of stress induced strain energy for recrystallization could be divided into two parts, one was the thermal stress generated by the solidification latent releasing in the recalescence process, and the other was accumulated stress and plastic strain resultant from interaction between primary dendrite and liquid flow driven by rapid solidification.& COPY; 2023 The Author(s). Published by Elsevier B.V.This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/).
10.1016-j.jmrt.2023.04.198	-1		The microstructure and the mechanical properties of a-phase Cu-5Sn alloy, Cu-10Sn alloy, and Cu-15Sn alloy (wt%) prepared by selective laser melting have been studied in this work. Under the same process condition, the laser absorption of the alloys increases continuously with the increase in Sn content. The optimal process parameters of the three alloys were obtained by Response Surface Method. The Sn content was found to have a significant effect on the relative density of the Cu-Sn alloys, as well as the laser power. The effect of laser power on the relative density of the alloys is weakened by the increase in laser absorption as the Sn content increases. Comparing the melt pool of the three alloys, they all show mainly columnar grains. As the Sn content increases, the size of the columnar grains becomes larger, and when the Sn content reaches 15 wt%, the columnar grains can penetrate through several melt pools. With the increase of Sn content from 5 wt% to 15 wt%, the tensile strength of the alloy increased from 382 MPa to 738 MPa, but the plasticity decreased significantly and the elongation decreased from 26% to 9%. As the Sn content increases from 5 to 15 wt%, the amount of solid-soluble Sn in the a-phase alloy increases, creating a lattice distortion stress field that effectively prevents dislocation movement. Thus, the stress field effectively increasing the yield and tensile strength of the alloy. Meanwhile, the increase in Sn content leads to the appearance of many brittle, hard and rich phases on the micron scale and precipitation from grain boundaries within the lattice, resulting in an increase in strength and a decrease in plasticity of the alloy. In conclusion, Cu-10Sn alloy has more excellent tensile properties and higher yield and tensile strengths with good ductility compared to Cu-5Sn and Cu-15Sn alloys. & COPY; 2023 The Authors. Published by Elsevier B.V. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/).
10.1016-j.jmrt.2023.04.249	15	aging; strength; conductivity; electrical conductivity; electrical; mpa; treatment; strengthening; degrees; cu-; cold; precipitation; tensile strength; tensile; iacs	A homogeneous CuCr50 alloy ingot prepared in situ by thermite reduction-electromagnetic casting is a type of nonequilibrium solidification structure with a Cu matrix supersaturated with Cr. In this study, the effects of heat treatment on the microstructure of the CuCr50 alloy were studied using scanning electron microscopy (SEM), metallography microscopy and transmission electron microscopy (TEM), and the conductivity, macrohardness and tensile strength of the CuCr50 alloy were measured. The obtained results show that the optimal heat treatment conditions are solution treatment (975 & DEG;C for 1 h) and aging treatment (500 & DEG;C for 2 h), for which the hardness, conductivity, and tensile strength of the CuCr50 alloy are the best; the macrohardness is 103.33 HB, the conductivity is 18.60 MS/m, and the tensile strength is 199.72 MPa. TEM characterization showed that nanosized Cr particles were precipitated and dispersed in the Cu matrix after the aging treatment; the relationship between the precipitates and the Cu matrix was incoherent, and Cu dissolved into the Cr phase in the form of a solid solution to strengthen the second Cr phase. & COPY; 2023 The Authors. Published by Elsevier B.V. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/).
10.1016-j.jmrt.2023.04.264	15	aging; strength; conductivity; electrical conductivity; electrical; mpa; treatment; strengthening; degrees; cu-; cold; precipitation; tensile strength; tensile; iacs	The phi 16 mm single crystal copper rod was prepared by heated-mold horizontal continuous casting, and the phi 16 mm polycrystalline copper rod was prepared by up-casting technology. Both of them were drawn to phi 0.2 mm, the conductivity, strength, elongation, and micro-structure evolution of single-crystal copper wire and polycrystal copper wire were compared and analyzed. The results show that the plasticity of as-cast single-crystal copper rod is 13.94% higher than that of as-cast polycrystalline copper rod. When drawing to phi 0.2 mm, a single crystal copper wire with high strength (506 MPa) and high conductivity (98.01% IACS). At the same deformation amount, the single crystal copper wire obviously deforms more slowly and has a higher plastic deformation capacity; the texture transformation of single crystal copper wire is from soft -> hard orientation, selective orientation to discrete dis-tribution, while the weave transformation of polycrystalline copper wire is from soft-> hard orientation, then from hard -> soft orientation, and finally stabilizes to selective orientation. The microstructural evolution of single-crystal copper wire and polycrystalline copper wire during continuous deformation was observed: dislocation entanglement into dislocation cells by slip -> microstrip structure -> lamellar organization -> twinning organization, single-crystal copper wire appears twinning later, single-crystal copper deformation coor-dination ability is better than polycrystalline copper. It is found that the increase of dislocation density, the decrease of grain width and the increase of < 111 > texture are the main factors for the strength improvement of micro-nano pure copper wires. (c) 2023 The Authors. Published by Elsevier B.V. This is an open access article under the CC BY license (http://creativecommons.org/licenses/by/4.0/).
10.1016-j.jmrt.2023.05.015	14	strength; properties; conductivity; electrical; mechanical; cu-; grain; mpa; electrical conductivity; aging; precipitation; phase; mechanical properties; tensile; phases	The evolution of the mechanical characteristics, residual stresses, and microstructure of a Cu-Fe-P alloy during machining was investigated, and the influence mechanism of the microstructure on the residual stress and strength of the Cu-Fe-P alloy was confirmed. The findings suggest that the tensile strength, transverse direction (TD), and rolling direction (RD) residual stresses in the cold-rolled state are 516 MPa, similar to 80 MPa and similar to 36 MPa, respectively, which are 76.1%, 93.8%, and 72.2% higher than those in the hot-rolled state, respectively. In addition, after annealing at high temperatures, the tensile strength, TD, and RD residual stresses of the Cu-Fe-P alloy decreased to 344 MPa, similar to 9 MPa and similar to 24 MPa, respectively, which were 33.3%, 88.8%, and 33.3% smaller than those of the cold-rolled alloy, respectively. The strength and residual stress of the Cu-Fe-P alloy are intriguing. The primary influencing aspects of the strength and residual stress are dislocations, grain boundaries, and textures. The residual stress of the Cu-Fe-P alloy may be controlled while maintaining strength by appropriately increasing the proportion of recrystallized grains and decreasing the dislocation density and volume fraction of the Brass texture, respectively. These outcomes serve as a guide for improving the service performance of Cu-Fe-P alloys. (c) 2023 The Authors. Published by Elsevier B.V. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/).
10.1016-j.jmrt.2023.05.174	2	corrosion; surface; film; electrochemical; films; spectroscopy; layer; current; solution; potential; resistance; composition; x-ray; ions; showed	Usually, corrosion processes on brass, which are manifested by discoloration of the metal or alloy surface, are a little destructive and slow in natural environment or non-acid solutions. In this context, investigation of the corrosion process under the above conditions can be a research area of great relevance because standard analysis such as weight loss and electrochemical techniques can not be applied. Here, we report on a digital image processing analysis of the evolution of copper and zinc alloy surfaces corrosion due to exposure to air, alcohol-aqueous solutions, and sugarcane liquor. For our analysis, we investigated 2D image produced by a confocal microscope from a topographic surface survey, by calculating parameters such as correlation coefficient, Hurst exponent, and bright/dark ratio to follow the early stage of the corrosion process evolution due to exposure to several conditions for different periods of time. The best fits are presented together with the image processing data to show the evolution of the surface characteristics as a function of time and treatment. We show that digital image of rough surfaces that have undergone early stage of the corrosion processes can be used to monitor surface changes. For all tested solutions, the changes in the surface can be better sensed by using the B/D ratio due to the large vertical scale but the fit was better for the correlation coefficient. Particularly for sugarcane liquor and 100% C2H5OH alcohol solution, B/D ratio varies slower than for the other solutions, thus, suggesting an inhibitory effect of this solution. & COPY; 2023 The Author(s). Published by Elsevier B.V. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/).
10.1016-j.jmrt.2023.05.209	-1		In this paper, we put a variety of elements into the Cu-Ni-Si alloy for smelting and pro-cessing, and systematically characterized and tested the microstructure, precipitates and service performance during the process. We found that adding Cr, Zr, Ti, and Mg led to grain refinement and produced some twin structures. In addition, based on Ni-Si pre-cipitates, the generation of the nano-Cr3Si phase (50 nm in size) is promoted, and their distribution in the matrix is relatively uniform. The dispersed precipitates can effectively strengthen the service performance of the copper alloy, and the strength of the alloy ex-ceeds 500 MPa while maintaining high conductivity. The research results of this paper can provide a basis for the design and development of copper alloy strips for new energy vehicle connections.& COPY; 2023 The Author(s). Published by Elsevier B.V. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/).
10.1016-j.jmrt.2023.05.225	15	aging; strength; conductivity; electrical conductivity; electrical; mpa; treatment; strengthening; degrees; cu-; cold; precipitation; tensile strength; tensile; iacs	Microalloying is an effective approach to improve the performance of CuCr alloys. This paper presents a new idea for the preparation of CuCrFe alloys by self-propagation reduction in-situ microalloying. It is found that the addition of Fe alloying components reduces the Gm and DGm of the CuCr melt, which inhibits the occurrence of the liquid phase decomposition process. When the Fe content of CuCrFe alloy is 1.5%, compared with the Cr-rich phase of CuCr alloy, the second phase undergoes significant refinement, the average particle size refined from 21.7 & mu;m to 19.3 & mu;m and the standard deviation reduced from 10.59 to 8.73, and the addition of Fe is beneficial to the spheroidization and refinement of the Cr-rich phase. Fe is mainly combined with Cr, and CuCrFe alloy still exists in the form of two phases. After solution thorn aging treatment, the average particle size of the second phase in CuCr alloy decreases from 21.8 & mu;m to 17.9 & mu;m, and that in CuCrFe alloy decreases from 19.6 & mu;m to 18.6 & mu;m. The conductivity of CuCrFe alloy increases from 10.5 MS m 1 to 15.9 MS m 1, and the hardness increases from 95.0 HB to 117.0 HB. After heat treatment, the nano-spherical are present in the Cr-rich phase of the CuCrFe alloy, while Fe is completely solid-soluble in the Cr-rich phase; the Cu-rich matrix shows a diffuse distribution of fine second phases, which play a role in strengthening the second phase in the matrix. & COPY; 2023 The Author(s). Published by Elsevier B.V. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/).
10.1016-j.jmrt.2023.06.109	-1		Ship propellers suffered from serious coupling damage of cavitation-erosion (CE) and corrosion when operated with high-speed in the marine environment. To improve the CEcorrosion resistance of the Ni-Al bronze (NAB) propeller alloy, a novel Cu-based mediumentropy alloy coating (Cu55Al20Ni12Ti8Si5, at%) was prepared by high-velocity oxygen-fuel spraying technology in this study. The characteristics and CE behavior of coating and NAB were comparatively investigated, then the CE damage mechanism was discussed by analyzing CE damage morphologies. The influence of CE on corrosion behavior and the coupling effect between CE and corrosion were further elucidated by electrochemical corrosion experiments. The results indicated that the as-sprayed coating mainly comprised of BCC solid solution phase and NiTi-rich precipitates, which possessed higher hardness (6.73 +/- 1.23 GPa) and superior resilience (27.0%) than the NAB. The cumulative mass loss rate for the coating after 18 h CE in distilled water and 3.5 wt% NaCl solution was only 38.7% and 80.6% that for the NAB, revealing the better anti-CE performance of the coating. The preferential CE of the BCC matrix around the NiTi-rich precipitates, fatigue fracture and lamellar spalling were summarized as the main CE damage mechanism for the coating in 3.5 wt% NaCl solution. CE had a significant influence on corrosion behavior of coating and NAB, which resulted in corrosion performance degradation of both two materials. The CE-corrosion coupling effect led to the remarkable mass loss, and mechanical effect rather than corrosion effect was ascribed to be the dominated factor for the damage of coating and NAB. (c) 2023 The Authors. Published by Elsevier B.V. This is an open access article under the CC
10.1016-j.jmrt.2023.07.072	-1		Cu-Ti alloys are candidates for replacing Cu-Be alloys owing to their excellent mechanical properties, bending properties, and stress relaxation resistance. However, the precipitation behavior of Cu-Ti alloys remains poorly understood. In this study, diffraction patterns, orientations, and morphologies of continuous and discontinuous precipitates in a Cu-3 wt% Ti (Cu-3Ti) alloy are investigated by transmission electron microscopy (TEM) and high -resolution transmission electron microscopy (HRTEM). In the peak-aging condition, numerous rod-like nanosized continuous precipitates (CP) of b0-Cu4Ti are uniformly distributed in the Cu-3Ti alloy. The CP retain their tetragonal structure, and their orien-tation relationships with the matrix are determined as [0011Cu//[0011b' and (010)Cu//(310)b', exhibiting six variants. With increasing aging time, discontinuous precipitates (DP) of b-Cu4Ti grow at the grain boundaries, displaying an orthorhombic structure (a 1/4 0.453 nm, b 1/4 0.4342 nm, and c 1/4 1.293 nm). The orientation relationships between the DP and the Cu -matrix are determined as (Laughlin and Cahn, 1975; Han et al, 2016; Datta and Soffa, 1976; Han et al, 2020; Huang et al, 2023; Soffa and Laughlin, 2004; Wang et al, 2021; Si et al, 2016; Markandeya et al, 2004; Nagarjuna et al, 2001) [1-101Cu//[5011b and (111)Cu//(010)b. Typical diffraction pattern models of the CP and DP in different directions were simulated, and the simulations were in good agreement with the experimental data. & COPY; 2023 The Author(s). Published by Elsevier B.V. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/).
10.1016-j.jmrt.2023.07.105	0	solidification; phase; magnetic; magnetic field; undercooling; field; liquid; separation; peritectic; immiscible; cu-; dendrite; phase separation; microstructure; primary	The present work systematically studied nonequilibrium solidification microstructure and its morphology evolution with undercooling of Cu60Ni40 binary alloy and Cu60Ni35Co5 ternary alloy, and the characteristic undercooling degree of alloy evolution was deter-mined. Combining with BCT model, dendritic growth of undercooled Cu-Ni alloy was studied. On the basis of the above, a new ternary single-phase alloy was formed by adding minor Co element into Cu60Ni40 alloy. Subsequently, a comparative analysis was con-ducted on Cu60Ni40 and Cu60Ni35Co5 alloys, exploring the effect of Co element on the evolution of microstructure of deeply undercooled Cu-Ni alloys.& COPY; 2023 The Author(s). Published by Elsevier B.V. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/).
10.1016-j.jmrt.2023.07.126	1	shape; memory; shape memory; damping; martensite; martensitic; damping capacity; transformation; capacity; strain; superelasticity; temperature; cu-al-mn; shape memory effect; effect	Ductile Cu-Al-Mn shape memory alloys obtain the damping capacity through the movement of martensite boundaries. To reduce the number of vacancies at martensite boundaries can improve their damping capacity. Our results showed that Ni alloying could remarkably suppress the vacancy movement during the process of cooling from high temperature and heating as well as ageing. The Cu-18.0Al-8.4Mn-2.5Ni alloy showed remarkably higher damping capacity than the Cu-18.0Al-9.4Mn alloy did due to the reduced vacancies at martensite boundaries by the Ni alloying, regardless of the direct quenching, up-quenching, and step-quenching. The occurrence of martensitic stabilization could rationalize the lower improvement of damping capacity in the up-quenched Cu-18.0Al9.4Mn alloy. The present results also further confirmed that the original number of vacancies at the martensite boundaries determined the occurrence of martensitic stabilization.& COPY; 2023 The Authors. Published by Elsevier B.V. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/).
10.1016-j.jmrt.2023.07.219	-1		Deep undercooling rapid solidification experiments of Cu-Ni-Co alloys were carried out using the molten glass purification cycle superheat method. 130 K, 177 K and 277 K undercooling degrees were obtained and analysed for Cu55Ni43Co2 alloy. The crystallographic information obtained by EBSD and the dynamics of the solidification front taken by high speed photography were analysed and it was concluded that both the formation of relatively rounded equiaxed grains during the first refinement and the subsequent formation of finer subcrystals were due to the release of a large amount of solidification energy during the solidification process. The re-glow stage releases a large amount of latent heat of solidification resulting in the remelting of the dendrites. TEM tests were carried out on Cu55Ni43Co2 alloy with a maximum undercooling of 277 K. It was found that part of the substructure showed a high density dislocation network. By analysing the effect of increasing undercooling on the microstructure evolution, combined with the EBSD and TEM characterisation data, it was found that the stress-induced recrystallization mechanism was the dominant factor in the grain refinement mechanism at large undercooling.& COPY; 2023 The Author(s). Published by Elsevier B.V. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/).
10.1016-j.jmrt.2023.07.239	-1		The friction-wear properties of conductive elastic connectors are rarely reported but are important. The Cu-8Ti-0.4Cr-0.4 Mg, Cu-8Ti-0.4Cr-0.4Mg-0.3Al, Cu-8Ti-0.4Cr-0.4Mg-0.3Fe (in atom%) were fabricated and studied, and after treated by CR 60% + 450 & DEG;C/30min + CR 50% + 400 & DEG;C/120 min + 400 & DEG;C/1 min their hardness achieved to 447 HV, 446 HV, and 437 HV, respectively. The effects of loads and speeds on the friction and wear behavior of the studied Cu-Ti alloys were investigated by friction and wear testing machines. The wear mechanism of the alloy is mainly abrasive wear, as tested at a load of 50 N and a speed of 121 mm/s. While the wear mechanisms of the alloy are mainly oxidation wear, adhesive wear, and abrasive wear, as tested at a load of 100 N and a speed of 363 r/min. These findings bring an extended understanding of the friction and wear application of ultra-high strength conductive Cu-Ti alloys. & COPY; 2023 The Authors. Published by Elsevier B.V. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/).
10.1016-j.jmrt.2023.08.012	-1		The effect of grain boundaries on the strength and electrical conductivity of annealed copper wires was studied. After annealing at 100 & DEG;C for 30 min, the copper wires retained a fiber-like structure. The increase in electrical conductivity is believed to stem from the decrease of crystallographic defects introduced by drawing. Recrystallization occurred when the annealing temperature reached 150 & DEG;C. The formation of small recrystallized grains led to the introduction of additional grain boundaries perpendicular to the drawing direction, resulting in a slight decrease in electrical conductivity. When the annealing temperature rose up to 200 & DEG;C, complete recrystallization took place in the copper wires. The grain boundaries parallel to the drawing direction play an important role in boundary strengthening, while the grain boundaries perpendicular to the drawing direction play an important role in both boundary strengthening and electron scattering. The electrical resistivity of grain boundaries in fully recrystallized copper wires at room temperature was determined experimentally, and an empirical relation is proposed to quickly determine the electric conductivity of copper wires at room temperature based on the boundary spacing along the drawing direction.& COPY; 2023 The Author(s). Published by Elsevier B.V. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/).
10.1016-j.jmrt.2023.08.046	-1		Pre-aging treatment before cold rolling and final aging was introduced to optimize the mechanical properties and electrical conductivity properties of Cu-0.75Fe-0.35Ti alloy. The alloy was pre-aged at 540 & DEG;C for 6 h, then cold rolled with thickness reduction of 80%, followed by aging at 460 & DEG;C for 2 h (SARA). Vickers hardness, electronic conductivity and uniaxial tensile tests were conducted to measure the mechanical and electrical conductivity properties. Electron backscatter diffraction and transmission electron microscope were used to characterize the microstructural evolution. The results showed that the hardness, tensile strength and electrical conductivity of SARA were up to 198.2 & PLUSMN; 4.8 HV, 622.6 & PLUSMN; 6.3 MPa and 63.8% IACS, respectively, which were superior to those achieved without pre-aging. The enhanced mechanical properties of SARA were attributed to an increase in low angle boundaries (LABs), geometrically necessary dislocation (GND) density and volume fraction of precipitates, while the favorable electrical conductivity was ascribed to the enhancement of precipitation and resultant matrix purification.& COPY; 2023 The Authors. Published by Elsevier B.V. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/).
10.1016-j.jmrt.2023.08.056	-1		In this study, the effects of differences in grain size, grain boundary type and misorientation on the initiation of discontinuous precipitates are investigated for the Cue5Ni e1.25Si alloy. Samples with different grain sizes are obtained by thermomechanical treatment, and the smaller the grain size, the higher the percentage of discontinuous precipitate at the same aging time, while there is no significant difference in the growth rate of the reaction front of discontinuous precipitates. EBSD is used to study the effect of grain boundary misorientation on discontinuous precipitates, the characteristics of discontinuous precipitates initiation on different grain boundaries are investigated by multivariate statistical analysis. It is found that discontinuous precipitates only initiate from random grain boundaries instead of coincident site lattice boundaries, where random grain boundaries with misorientation angles of 30-50 degrees are more prone to discontinuous precipitates. And the initiation of DPs at different misorientation axes is different. There is a clear borderline for the axes such as < 102 >, < 103 >, and < 203 >. The grain boundaries below this borderline do not initiate DP, while all grain boundaries below this angle initiate DPs. The cases for axes such as < 112 >, < 114 >, and < 214 > are more complicated. On these misorientation axes, grain boundaries with lower or higher misorientation angles do not initiate DPs, while grain boundaries at intermediate range misorientation angles do initiate DPs. (c) 2023 The Authors. Published by Elsevier B.V. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/).
10.1016-j.jmrt.2023.08.080	14	strength; properties; conductivity; electrical; mechanical; cu-; grain; mpa; electrical conductivity; aging; precipitation; phase; mechanical properties; tensile; phases	Through the incorporation of phosphorus (P) as a third component, an in-situ formation of a magnetic phase with a nanotwin structure was achieved. The utilization of selective laser melting (SLM) enabled the synthesis of a Cu-Fe-P immiscible alloy that exhibits an integrated structure and function. The microstructure predominantly consists of a magnetic heterogeneous Fe-P-rich phase, comprising a mixture of Fe2P and a small quantity of Fe3P, which is distributed within the & epsilon;-Cu Cu-rich matrix in alternating fiber -layer and particle-shape forms. Additionally, the fibrous Fe2P phase exhibited precipitation of a-Fe, while the Fe-P-rich phase experienced the precipitation of high-density nanotwinned Cu (nt-Cu) particles. The microstructure density and structural characteristics of Cu-Fe-P immiscible alloys were enhanced through the adjustment of laser energy density, leading to improvements in their mechanical and magnetic prop-erties. It was observed that the microstructure density initially increased and then decreased with increasing laser energy density. The highest relative density of the Cu-Fe-P immiscible alloy microstructure (98%) was achieved at a laser energy density of 53 J/mm3. Furthermore, the influence of laser energy density on the mechanical and soft magnetic properties of Cu-Fe-P immiscible alloys was examined. The findings indicate that the mechanical and soft magnetic properties of these alloys are affected by the laser energy density. The findings indicate that the compact Cu-Fe-P immiscible alloys exhibit favorable compression mechanical properties and soft magnetic properties. Specifically, the ultimate compressive stress can reach 890.5 & PLUSMN; 20 MPa, while the failure strain can reach 20.5 & PLUSMN; 2%. Additionally, the coercivity is observed to be as low as 20.0 Oe, the magnetic saturation strength as high as 93.5 emu/g, and the residual magnetization at 1.1 emu/g.& COPY; 2023 The Author(s). Published by Elsevier B.V. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/).
10.1016-j.jmrt.2023.08.136	1	shape; memory; shape memory; damping; martensite; martensitic; damping capacity; transformation; capacity; strain; superelasticity; temperature; cu-al-mn; shape memory effect; effect	In this work, two Cu-Al-Mn shape memory alloys (SMAs), Cu-12.5Al-3Mn and Cu-12.5Al -3Mn-1Ni, were prepared by wire arc melting deposition, and their shape recovery rates, ultimate recoverable strains, additive manufacturing microstructures, memory recovery behaviors, and phase transition properties were comparatively investigated. Meanwhile, the mechanism of Ni in these two alloys was discussed by combining the differences in phase composition of the two alloys. Results showed that the shape recovery rate of Cu12.5Al-3Mn alloy decreased linearly with increasing pre-strain, from 91.23% at 4% prestrain to 62.41% at 10% pre-strain, and its ultimate recoverable strain was approximately 7%; while the shape recovery rate of Cu-12.5Al-3Mn-1Ni SMA was 100% at 4%-8% prestrain, and remained at 96.57% until the pre-strain was increased to 10%, i.e., the recoverable strain was more than 9%. In addition, the phase change temperature of the alloy with Ni addition decreased compared to that of the alloy without Ni addition, especially the temperature hysteresis was narrower. The results indicate the formation of a new k phase after adding Ni to the alloy. The pinning effect of this new phase significantly improves the order of martensite within the alloy. Moreover, Ni also induces the transformation of the alloy, inhibiting the precipitation of the brittle phase g2 and leading to a marked increase in the shape memory recovery rate and the recoverable strain of the additively fabricated Cu -Al-Mn alloy. Note that Ni transforms the alloy from hyper-eutectoid components to eutectoid components. Moreover, after adding Ni, the thermoelastic martensite phase transition temperature and temperature hysteresis decreased together with its eutectoid temperature, which made the additive manufacturing Cu-Al-Mn SMA exhibit an explosive response behavior. & COPY; 2023 The Author(s). Published by Elsevier B.V. This is an open access article under the CC
10.1016-j.jmrt.2023.08.137	-1		High-temperature destabilization of the strengthening phase and the generation of discontinuous precipitation at grain boundaries are mutual problem in current high-temperature alloys, especially in the novel Cu-based high-temperature alloys. In the present work, multicomponent composition design is utilized to inhibit discontinuous precipitation and improve the stability of the y' phase by strong enthalpic interactions between elements, while introducing coherent precipitated phases other than the y' phase into the alloy to simultaneously enhance the heat resistance of the alloy. The Cu85.71Ni10.72-x Al3.57Mx (M = Ti, Nb and V) alloys designed are multi-scale-phases coherent precipitation-strengthened copper alloys, as shown by systematic electron diffraction and HRTEM analysis. In-situ analysis of high temperature hardness and electrical resistivity showed that the softening rate of hardness and the rising rate of electrical resistivity decreased significantly after adding M during the heating process. The calculation results by Thermo-calc also confirmed that the addition of M delayed the re-dissolution of the y' phase to improve its thermal stability, and introduced additional coherent precipitated phases which remains a strengthening effect after the re-dissolution of the y' phase at high temperature. The enhanced stability of y' phase originates from the strong enthalpic interaction between elements and is also related to the promotion of precipitation of Al and reduction of vacancies and antisites in y' phase by adding M. In summary, multi-scale-phases coherent precipitation strengthening is an effective way to enhance the comprehensive performance of novel Cu-based high-temperature alloys, and also provides a new perspective for the development of heat-resistant alloys with excellent performance.& COPY; 2023 The Author(s). Published by Elsevier B.V. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/).
10.1016-j.jmrt.2023.08.156	-1		Cu-Al2O3-TiB2 is an important high-performance dual-phase dispersion strengthened copper alloy. The problem of serious coarseness and agglomeration of TiB2 and Al2O3 particles is a bottleneck that restricts the preparation of high-performance Cu-Al2O3-TiB2 alloys by traditional liquid- phase in-situ reaction method. In this paper, an idea of combining the split cavity melting of complex reactants and efficient solidification of melt was proposed, and a new liquid phase in-situ reaction technology for dual-phase strengthened metal matrix composites was invented. Compared with the traditional liquid phase in-situ reaction method, the strengthening particles in the Cu-0.75Al(2)O(3)-0.75TiB(2) (wt%, nominal composition) prepared by the new liquid phase in-situ reaction technology were more uniform, and the tensile strength and hardness were significantly improved. Large-deformation cold rolling can improve distribution of particles. With the increase of deformation, the main deformation mode of the composite changed from matrix plastic deformation to matrix-particle shear deformation, with the main fracture mechanism changing fromparticle-matrix interface fracture to particle shear fracture. The new liquid phase in-situ reaction technology effectively solved the problem of particle coarsening and agglomeration in Cu-Al2O3-TiB2 composites. The new liquid phase in-situ reaction technology combined with large deformation is a new process with high efficiency and short flow for preparing dual-phase dispersion strengthened copper alloys. (c) 2023 The Author(s). Published by Elsevier B.V. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/).
10.1016-j.jmrt.2023.08.253	-1		In the work, the cryogenic and room temperature drawing behaviors of Cu-Te alloy with a wide range of accumulative drawing true strain up to 1.1 are systematically investigated. For the first time, the storage of geometrically necessary dislocations (GND) and statically stored dislocations (SSD), occurrence of deformation twinning, as well as their respective roles in strain hardening in the drawn Cu-Te alloy at cryogenic and room temperature have been studied. The results show that the liquid nitrogen temperature drawn (LNT-D) Cu-Te alloy presents higher yield strength (YS), ultimate tensile strength than the room temperature drawn (RT-D) Cu-Te alloy. Microstructural investigation reveals that cryo-genic wire drawing of Cu-Te alloy promotes the formation of simultaneous twinning and shear bands, accompanied by the fragmentation of Cu2Te phase. The LNT-D Cu-Te alloy exhibits planar slip characteristics, while RT-D Cu-Te alloy presents wave slip charac-teristics. Compared with RT-D Cu-Te alloy, the higher YS of LNT-D Cu-Te alloy can be mainly attributed to dislocation strengthening and twinning strengthening, which account for 76.25-80.45% and 4.79-4.91% of the total YS respectively. During room temperature drawing, both GND and SSD play an important role in the hardening of Cu-Te alloy. During cryogenic temperature drawing, work hardening is predominantly through rapid multi-plication of SSDs. (c) 2023 The Authors. Published by Elsevier B.V. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/).
10.1016-j.jmrt.2023.08.282	-1		The hot deformation behavior of Cu-Sn-Ti-(Cr) alloys was studied using Gleeble-1500D thermo-mechanical simulator ranging from 550 to 950 degrees C, and the strain rate was 0.001 -10 s-1. The microstructure evolution of the alloy was analyzed using characterization methods such as electron backscatter diffraction (EBSD), scanning electron microscope (SEM) and transmission electron microscope (TEM). Cu-Sn-Ti-(Cr) alloys were calculated by establishing the constitutive equation of the alloy. The activation energies of Cu-Sn-Ti and Cu-Sn-Ti-Cr alloys are 275.884 and 283.550 kJ/mol, respectively. The results indicate that the addition of Cr element has an inhibitory effect on the nucleation and improve refinement of dynamic recrystallization (DRX) in Cu-Sn-Ti alloy. The texture of Cu-Sn-Ti alloy is Cu texture at 750 degrees C and the texture contained in Cu-Sn-Ti alloy is Goss texture, Cubic texture and Cu texture when the temperature is raised to 950 degrees C. The texture of Cu -Sn-Ti-Cr alloy at 750 degrees C is Goss texture. The Goss texture transforms into Cubic texture and Cu texture when the temperature is raised to 950 degrees C. The precipitates present in Cu-Sn -Ti alloy include CuSn3Ti5 phase and Cu4Ti phase. The addition of Cr element adds a new phase of Cr to the alloy and also makes the distribution of precipitates more uniform and increases in quantity. (c) 2023 Published by Elsevier B.V. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/).
10.1016-j.jmrt.2023.09.078	-1		The stability and strength of the grain boundary (GB) structure are critical for the practical application of nanocrystals. This study systematically calculates the impact of the segregation of 26 transitional alloy elements on Cu S11 [110](113) GB using the first-principle theoretical calculation method. The research findings demonstrate that there is a parabolic connection between atomic number and segregation energy of TM elements in the same period. In addition to Fe, Co, and Ni, all other 23 elements have the potential to segregate to Cu GB, with Zr exhibiting the strongest segregation tendency. The difference in atomic radius and electronegativity between solute atoms and copper atoms strongly affects the segregation tendency, the greater the difference, the greater the tendency for segregation. The segregation energy of solute segregation has strong linear correlation with its GB energy, and the stronger the segregation ability, the more stable the GB. Except for Zn, Ag, Cd, and Au, other 19 alloying elements can increase the strength of GB. Electronic analysis indicates that the strengthening and embrittlement of solutes are primarily related to the accumulation and consumption of electrons near GB and the bonding between atoms.(c) 2023 The Authors. Published by Elsevier B.V. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/).
10.1016-j.jmrt.2023.09.140	-1		Brass cladding copper stranded wire with an outer diameter of 10 mm and core material of d2.12mm x 7 strand was prepared by solid-liquid composite method with continuous pouring process for clad. Compared with the cladding welding method which requires multiple drawings to make the composite welding wire achieve metallurgical bonding, it saves a lot of manpower and material resources and shortens the production cycle. The bonding mechanism of brass and copper was analyzed by experiments, meanwhile, the effects of brass melt temperature and casting speed on the surface quality and interface bonding quality of the composite wire were investigated. The results show that, on the one hand, increasing the melt temperature of brass and reducing the casting speed can inhibit the surface defects of the composite. On the other hand, reducing the temperature of the brass melt and increasing the casting speed can inhibit the excessive element diffusion at the bonding interface, thereby reducing the degree of surface erosion of the copper strand. The final reasonable process parameters are as follows: the brass melt temperature is 970 degrees C-990 degrees C, the traction speed is 40 mm/min-80 mm/min, and the cooling water volume of the crystallizer is 450L/h . The prepared brass cladding copper stranded wire has good quality, Vickers hardness is between 80 -85HV, and tensile strength is between 265 -297 MPa. Elongation after fracture is 40.3%-43.9%, conductivity is 53.8-62.1% IACS.(c) 2023 The Author(s). Published by Elsevier B.V. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/).
10.1016-j.jmrt.2023.09.193	-1		The TiB2p/Cu composites were prepared by current-assisted vacuum hot pressing (CAVHP) combined with rolling using in-situ spherical TiB2p/Cu composite powder as raw material. The effects of rolling deformation on the microstructure and properties of the sintered TiB2p/Cu composite were investigated. The results show that CAVHP leads to a rapid densification of the composite powder compact, and the subsequent rolling deformation is able to eliminate the unclosed pores and achieve a uniform distribution of TiB2p. The dynamic recrystallization during cold rolling refines the Cu matrix grains to ultrafine grains with an average grain size of 0.47 mm. The cold rolled TiB2p/Cu composite obtains a remarkable comprehensive performance with ultimate tensile strength, yield strength and electrical conductivity of 621 MPa, 567 MPa and 86.3% IACS, respectively. In addition, the strengthening and fracture mechanism of the cold rolled TiB2p/Cu composite are analyzed. This work will explore a new technological solution for the preparation of highperformance Cu matrix composites. (c) 2023 The Authors. Published by Elsevier B.V. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/).
10.1016-j.jmrt.2023.09.200	-1		Copper matrix composite reinforced with SiC exhibits high electrical and thermal conductivity, as well as superior mechanical properties, making it a potential candidate for thermal management applications. There has been rapid progress in the understanding of Cu-SiC metal matrix composites during the past decade. To accomplish this, powder metallurgy, casting, selective laser melting, composite electroforming technology, and electrodeposition methods have been employed. The optimum cutting conditions for fabrication of Cu-SiC metal matrix composites are still being explored. In recent years, friction stir processing (FSP) has become increasingly popular in the fabrication of composites. FSP is capable of microstructural engineering in Cu-SiC systems. In light of the fact that the electrical/thermal conductivity and mechanical performance of Cu-SiC composites depend on microstructural characteristics such as SiC distribution, grain size, grain orientation, density of dislocations, and bulk density, it seems important to study the effect of manufacturing conditions on microstructure in detail. In this study, the influence of FSP parameters such as rotational and traversal speeds, the number of FSP passes, and the pin profile as well as the characteristics of SiC powder are discussed in detail with regard to macro-and microstructure, hardness, strength, tribological, and electrical properties of FSPed Cu-SiC composites. (c) 2023 The Author(s). Published by Elsevier B.V. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/).
10.1016-j.jmrt.2023.09.262	-1		The objective of this study is to investigate the effects of prestrain-assisted friction stir processing and subsequent aging heat treatment on the microstructural evolution and performance of copper-chromium-zirconium alloys. The findings indicated that prestrain, generated through cold rolling before friction stir processing, considerably affected grain refinement and enhanced the mechanical properties and electrical conductivity in the processing zone. The prestrain not only decreased the activation energy of dynamic restoration and precipitation in the processing zone, but also strengthened the constraint effect of the base metals to the processing zone. This effectively reduced the width of micro-bands and promoted nanocrystalline formation in the processing zone. Furthermore, dynamic precipitation resulted in higher thermal stability of the microstructure in the processing zone during subsequent aging heat treatment. Thus, the synergistic improvement of the mechanical properties and electrical conductivity of copperchromium-zirconium alloys was successfully achieved. (c) 2023 The Author(s). Published by Elsevier B.V. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/).
10.1016-j.jmrt.2023.09.264	8	hot; deformation; strain; strain rate; dynamic; hot deformation; recrystallization; dynamic recrystallization; flow; rate; flow stress; compression; constitutive; degrees; stress	The hot deformation behaviour of an as-cast Cu-20Ni-20Mn alloy was investigated by isothermal compression tests in a TA-DIL 805 phase change thermal expansion instrument with a temperature ranging from 800 to 950 degrees C and a strain-rate ranging from 0.001 s-1 to 1 s-1. The results showed that Cu-20Ni-20Mn presented a stress drop at the beginning of the strain, and the flow stress decreased with increasing temperature and decreasing of strain rate. In particular, the hot deformation activation energy was determined to be 277.958 kJ/mol. The hot compression constitutive equation was established, and the pro-cessing maps of the alloy were constructed. The stress-strain values predicted by the proposed model were coincident with the experimental results, which confirmed that the deformation principal equation gives an accurate and precise estimate of the flow stress in Cu-20Ni-20Mn. The established processing maps and microstructure analysis determined the rolling process parameters in which the optimum range of temperature for the hot-working deformation of the as-cast Cu-20Ni-20Mn alloy is 810-900 degrees C with a strain rate of 0.001-0.002 s-1.(c) 2023 The Authors. Published by Elsevier B.V. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/).
10.1016-j.jmrt.2023.09.273	6	grain; deformation; strain; strength; dislocation; cu-; tensile; size; ecap; grain size; sfe; ductility; hardening; high; stress	Cu-Fe alloys are expected to be extensively used in electronics, transportation and machinery industries due to the extraordinary mechanical properties and functional properties. To optimize rolling process and the final properties of Cu-Fe plates. The effect of rolling path, rolling temperature and thickness reduction on microstructure evolution, mechanical and electrical properties of Cu-Fe alloy are carefully investigated. The results shown that the thickness reduction has a significant effect on mechanical properties of Cu-Fe alloy. The yield strength of Cu-Fe plates with 20% thickness reduction is more than 2 times higher than that of homogenized ingot. While the yield strength increases gradually as further increasing the thickness reduction. Rolling temperature is an important parameter determining the strength-ductility balance. The strength of plate rolled with 80% thickness reduction at 400 degrees C is similar to that of the plates in cold-rolled state, and the ductility is higher than that for the plates in the cold-rolled state. Further investigation reveals that the formation of heterogeneous structure characterized with recrystallized-fine grains embedded in deformed-coarse grains is responsible for the observed extraordinary mechanical properties. Rolling path could also affect the micro-structure evolution and formability of the plates. For plate rolled with route 1 (unidirec-tional rolling), a stronger Copper-type texture with two Brass-type textures are observed. For plate rolled with route 2, where the rolled plate is rotated to 90 degrees with respect to previous rolling direction between adjacent rolling passes, only Brass-type texture is generated. A rolling-path dependent edge-crack behavior is observed during rolling. Edge cracks are generated during rolling with route 2, while the edge cracks are not observed for plates rolled with route 1. Factors affecting the edge-cracks behavior are also discussed.(c) 2023 The Authors. Published by Elsevier B.V. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/).
10.1016-j.jmrt.2023.09.280	-1		Brake pads play a vital role in controlling the operation of high-speed trains with over 300 km/h . Currently the copper-based composites produced by powder metallurgy tech-niques have been proved as one of the ideal materials. However,the braking performance is strongly influenced by the chemical composition, production, microstructure as well as the working conditions. The intrinsic mechanism of the thermal fade and wear loss under thermal and mechanical coupled influence has not yet been fully revealed. As of late, machine learning algorithms have attracted widespread attention and extraordinary re-sults has been accomplished in materials science and engineering. In this study the al-gorithms for predicting the braking performance of copper-based brake pads are developed. A new PM copper-based alloy, was designed via the models of the coefficient of friction (COF) and wear loss. The braking test results of this alloy show that the average COF was 0.37 at stable stage I and thermal recession decrease only 0.012 at stage II when under 350 km/h/0.48 MPa continuous braking for 10 times. And the total wear loss is only 1.30 g when under braking from 200 km/h to 350 km/h with pressure from 0.31 MPa to 0.48 MPa. Compared with the commercial brake pads, our designed alloy exhibits excellent braking performance with COF for thermal fade reduced to 21% and the total wear loss reduced to 20%.(c) 2023 The Authors. Published by Elsevier B.V. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/).
10.1016-j.jmrt.2023.10.066	-1		In this work, the high throughput sample of Cu-xIn (x = 0-5 wt%) alloy was prepared by the spark plasma sintering. The effects of In content on the microstructure and properties of Cu alloys were investigated using advanced characterization. The results show that the concentration of In element linearly distributes in Cu alloy after annealing treatment at 450 degrees C. Most In elements exist in the Cu matrix as the solid solution atoms. Some In elements are precipitated at the grain boundaries as Cu9In4 particles when the In content is higher. The hardness of the alloy increases, while the conductivity decreases with the increase of In content, which is due to the hindrance of the movement of dislocations and electrons by solid solution atoms, grain boundaries, and Cu9In4 particles. The investigation of high throughput samples can provide data support for high strength and high conductivity Cu alloys. (c) 2023 The Author(s). Published by Elsevier B.V. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/).
10.1016-j.jmrt.2023.10.072	15	aging; strength; conductivity; electrical conductivity; electrical; mpa; treatment; strengthening; degrees; cu-; cold; precipitation; tensile strength; tensile; iacs	The Cu-15Ni-8Sn alloy ingot was prepared in the medium-frequency induction melting furnace. The hot extruded alloy was treated by solid solution at 840 degrees C for 60 min and aging at 400 degrees C for different times (0 mi & ntilde;480 min). The effect of aging time on the evolution of the nanophase of Cu-15Ni-8Sn alloy and the strengthening-toughening mechanism were studied. The results show that at the beginning of aging, the alloy undergoes spinodal decomposition, the wavelength of the modulated structure is approximately 3 similar to 7 nm, the ordered phase transformation of D0(22) and L1(2) occurs simultaneously, and the ordered phase size is approximately 5 nm. With the extension of aging time, the modulated structure became coarser, and the wavelength of the modulated structure increased to 5-9 nm. At the same time, the D0(22) ordered phase changed to the L1(2) ordered phase, and a continuous distribution of elliptical discontinuous precipitation appeared at the grain boundary. The ratio of the long and short axes of the discontinuous precipitation was approximately 4.7. In the late aging period, the D0(22) ordered phase was basically transformed into the L1(2) ordered phase, and discontinuous precipitation, which is incompatible with the matrix, extended into the crystal. After 120 min of aging at 400 degrees C, the hardness, strength, and elongation of the alloy are 105.4 HRB, 839.8 MPa and 9.6 %, respectively. The peak-aging states D0(22) and L1(2) coexist in an orderly phase at the nanoscale, and this nanoscale strengthening phase is completely integrated with the matrix, which improves the strength and toughness of the alloy. The research results can provide support for the development of high-performance copper alloys in the ocean.(c) 2023 The Authors. Published by Elsevier B.V. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/).
10.1016-j.jmrt.2023.10.123	-1		In this paper, FeCoNiCrAl high-entropy alloy particles were used as reinforcement to fabricate Cu matrix surface composites by friction stirring processing. The x-ray diffraction (XRD), field emission scanning electron microscopy (FESEM) with energy dispersive X-ray spectroscopy (EDS), and electron backscattered diffraction (EBSD) were used to characterize the microstructure and phase composition of the composites. The microhardness tester and universal testing machine were also used to investigate the mechanical properties of the composites. The results demonstrated that the FSP and the adding of HEA particles greatly reduced the average grain size of the composites and increased the percentage of high-angle grain boundaries. A diffusion layer of AlCoCrFeNiCux solid solution with a single face-centered cubic structure was formed between the HEA particles and the Cu matrix. The thickness of the diffusion layer was about 0.9 mm. The microhardness, tensile strength and elongation of the prepared composite increased by 54.86 %, 17.17 % and 8.4 % respectively in comparison to the base Cu. The fracture morphology showed that most of the fracture locations occurred at the junction of diffusion layer and HEA particle, and a small number of fracture locations occurred at HEA particle, which ensured the joint enhancement of plasticity and strength of the composite. The fracture mode of Cu matrix in the composite was mainly ductile fracture. The fracture pattern at the HEA/Cu interface was mainly brittle fracture, accompanied by a small amount of ductile fracture. (c) 2023 The Authors. Published by Elsevier B.V. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/).
10.1016-j.jmrt.2023.10.211	-1		In this study, Cu-2.7Ti-0.2Fe (CT-0.2Fe) and Cu-2.7Ti-1Fe (CT-1Fe) alloys were fabricated and underwent multi -stage thermomechanical treatment, and the microstructure and properties evolution of the alloys during aging were investigated. After aging for 60 h at 350 C, the CT-0.2Fe and CT-1Fe alloys exhibited the yield strength of 1068/935 MPa, tensile strength of 1127/1057 MPa, elongation of 2.54%/2.21%, and electrical conductivity of 20.3/26.4 %IACS, respectively. The relatively higher electrical conductivity of CT-1Fe was primarily attributed to the formation of numerous TiFe particles. Typical modulated structure and beta'-Cu4Ti precipitates formed during direct aging in both alloys. However, in the CT-1Fe alloy, the growth of beta'-Cu4Ti precipitates was suppressed. During multi-stage thermomechanical treatment, the interaction of the dislocations and precipitates was enhanced, retarding the softening effects of the alloy at the elevated temperatures. The calculation results showed that work hardening and precipitation strengthening significantly contributed to enhancing the me-chanical properties of the alloys.
10.1016-j.jmrt.2023.10.255	-1		Cu-Cr-Ti alloy was successfully prepared by vacuum melting, solution treatment at 960 degrees C for 1 h, 80 % cold rolling and aging at 500 degrees C for 1 h . The effect of Ti content on the microstructure was characterized by Scanning electron microscope (SEM) and Transmission electron microscope (TEM). Their tensile strength, electrical conductivity, thermal stability, wear resistance and arc erosion resistance were also measured. The results showed that Ti can form the Ti0.77S phase with S, which can prevent the occurrence of sulfur embrittlement. And Ti can segregate around the Cr precipitates, hindering their growth . Therefore, the tensile strength, hardness, high temperature softening resistance, wear resistance and arc erosion resistance improved with the increase of Ti content. But the electrical conductivity decreased sharply since Ti was mainly solidly dissolved in the matrix. What's more, the electrical conductivity decreased sharply and other properties did not improve when the content increased from 0.066 wt% to 0.098 wt%, that is, the comprehensive performance was the best when the Ti content was 0.066 wt%. The tensile strength was 551 MPa, electrical conductivity was 78.3%IACS and the friction coefficient was 0.33. This work provides effective ideas for preparing copper alloys with desired properties.
10.1016-j.jmrt.2023.10.305	-1		A novel continuous expanding extrusion process for manufacturing Cu-Cr-Zr strips was proposed in the present study. The U-shaped strips with a cross-section of 420 mm x 19 mm were successfully prepared by taking the upward continuous casted Phi 28 mm rods as raw material. Electron backscattered diffraction (EBSD) and transmission electron microscopy (TEM) were employed to characterize the microstructure and precipitates, respectively, which revealed that the microstructure of the continuous extruded strip is very fine and uniform across the entire cross-section and the Cr precipitates are in a dispersed distribution in the matrix helping to improve the strength of the alloy. The average grain size is approximately 1 mu m and much smaller than that of the as-cast state (in millimeters). The average micro-hardness, tensile strength, and electrical conductivity of the extruded strip are 120 HV, 328.8 MPa, and 82.6 % IACS, respectively, increasing approximately by 31.6 %, 29.3 %, and 125.5 % in comparison to these of the as-cast state. In addition, the fracture elongation can maintain a very high level (average value similar to 28.9 %). The strengthening mechanisms were then quantitatively calculated, which showed that grain boundary strengthening, precipitation strengthening, and dislocation strengthening take comparable contributions. Thus, our investigations provide new insights into manufacturing high-performance Cu-Cr-Zr strips.
10.1016-j.jmrt.2023.11.019	-1		The effects of interfacial energy on precipitation behavior and physical properties of Cu-Ni-Si-(Co) alloys were investigated. The Cu-1.3Ni-0.3Si and Cu-1.3Ni-0.6Si-1.0Co alloys (in weight %) were prepared by combined cold-rolling and aging processes. The addition of Co promoted the formation of (Ni,Co)2Si by replacing Ni with Co in Ni2Si. Ab initio calculations demonstrated that the small addition of Co considerably reduced the interfacial energy between the Cu matrix and (Ni,Co)2Si, which effectively decreased the activation energy for precipitation. As a result, the precipitation of fine rod-shaped (Ni,Co)2Si was accelerated during the aging process and the number density of the precipitates increased up to 9.0 x 1010 cm-2. The nano-scale (Ni,Co)2Si precipitates with an average size of 13.5 nm strengthened the alloy properly through the Orowan mechanism without much loss of electrical conductivity. The maximum hardness and electrical conductivity were 220 HV and 51 % International Annealed Copper Standard, respectively, for the Cu-1.3Ni-0.6Si-1.0Co alloy aged for 4 h at 420 degrees C.
10.1016-j.jmrt.2023.11.158	-1		Copper-tungsten (CuW) composites have been explored in throat lining applications for the rudders and nozzles in the rocket motors, hence it is crucial to investigate their high-temperature ablation behaviors and the cor-responding failure mechanisms. Herein, xCu modified reduced graphene oxide reinforced CuW (named as Cu@rGO/ CuW) composites (x = 0, 1, 3 and 5 wt%) were fabricated using spark plasma sintering to evaluate their ablation resistances under an oxyacetylene torch flame and to improve their high temperature ablation resistance with in-situ formed tungsten carbides (WC and W2C) during sintering. The composite's surface after ablation can be clearly divided into two regions, i.e., central erosion region and edge transitional region. The ablation products were mainly consisted of WO3, CuWO4 and WC phases. The mass ablation rate and linear ablation rate of 3 wt% Cu@rGO/CuW composite were 0.015 g/s and 0.0023 mm/s, which are 0.25 and 0.3 times smaller than those of the monolithic CuW alloy, respectively. The superior elevated temperature ablation resistance of the composites was attributed to transpiration cooling of Cu and WO3, heat consumptions of the remained Cu@rGO with a high thermal conductivity, and in-situ formation of WC or W2C particles with high melting points. The key failure mechanisms of the Cu@rGO/CuW composites during ablation process with high temperature are thermo-chemical oxidation and thermo-mechanical ablation of oxides such as WO3, Cu2O and CuWO4.
10.1016-j.jmrt.2023.11.220	-1		The development and research of high strength and conductivity materials are essential for the advancement of high-field magnets, including pulsed magnets. This study investigates the effect of electromagnetic fields on the solidification casting of binary Cu-6wt%Ag alloy ingots with diameters of 40 and 160 mm. A 3D numerical simulation is performed utilizing the continuum model with conservation of total momentum, mass, energy, and species. The results indicate that applying electromagnetic stirring (EMS) to small cross-section ingots can cause many randomly distributed small regions with higher segregation degrees inside the ingot, which is not conducive to improving the macrosegregation inside the ingot. For large cross-section ingots without EMS, compared to small cross-section ingots, there is more severe macrosegregation inside the ingot, especially the extreme center segregation with a maximum segregation degree of about 414%. EMS can effectively control macrosegregation within a specific range and eliminate center segregation. When the linear EMS's magnetic induction intensity is set to 0.06 T, the maximum segregation degree near the ingot center can be reduced to less than 260%. Simultaneously, the EMS induced forced convection is also instability, leading to numerous haphazard solute accumulations and depletions, which explains many small segregation regions in the ingot. In terms of improving macrosegregation in large cross-section ingots, Linear EMS has a definite advantage over rotary EMS. It is possible to keep the entire segregation degree in the ingot below 100% when the linear EMS's magnetic induction intensity is set to 0.036 T and the stirring frequency is 4 Hz. The ideal stirring parameters range for linear EMS is to maintain the magnetic induction intensity at around 0.036 T and the stirring frequency in the range of 4-8 Hz.
10.1016-j.jmrt.2023.11.231	-1		The microstructural evolution of a single-phase Cu-12Mn-3Ni alloy during rolling and annealing has been investigated using electron backscatter diffraction and X-ray diffraction techniques. We have established the effects of microstructural characteristics on material strength and the temperature coefficient of resistance (TCR). The yield strength increased to 682 MPa after cold rolling with a strain of 0.87 due to an increase in the density of dislocation and low-angle grain boundary. A significant annealing softening is observed for the cold-rolled Cu-Mn-Ni alloy at temperatures above 400 degrees C, caused by recrystallization. The difference in yield strength for fully recrystallized alloys is mainly attributed to a difference in grain size, consistent with the Hall-Petch relationship. The addition of Ni and Mn enhanced the degree of difficulty in dislocation passing through the grain boundary, resulting in a higher Hall-Petch constant (274 MPa mu m1/2) for Cu-12Mn-3Ni alloys when compared with pure copper. The TCR is related to grain size, dislocation and Cu-12Mn-3Ni alloy texture. Grain coarsening and reduced dislocation density can effectively enhance the resistance temperature stability. In addition, the strong copper texture formed during cold rolling results in a difference in TCR associated with the rolling di-rection (RD) and transverse direction (TD) of the cold-rolled sheet. The Cu-Mn-Ni alloy crystal exhibits a lower resistance sensitivity to temperature when the [110]Cu direction is parallel to the current direction compared with the [111]Cu direction parallel to the current direction. The absolute value of the TCR in the TD of the cold-rolled sheet is 10.2 x 10-6 degrees C-1, lower than that in the RD (19.3 x 10-6 degrees C-1).
10.1016-j.jmrt.2023.11.263	6	grain; deformation; strain; strength; dislocation; cu-; tensile; size; ecap; grain size; sfe; ductility; hardening; high; stress	The design of gradient structure (GS) in metallic materials has been reported to obtain superior mechanical properties due to the interaction between the GS layer and the coarse-grained (CG) matrix. In this study, the mechanical response and microstructural evolution of the corresponding constituent layers of GS Cu-4.5Al alloy at different pre-strains were systematically investigated. The tensile results showed that the strain hardening capability of the GS layer was improved due to the constraint of the CG matrix. Meanwhile, an extra strengthening was observed at the interface between the GS layer and the CG matrix, resulting in a higher yield strength of the CG matrix constrained by the GS layer than that of the CG matrix without the GS layer constraints. Moreover, the extra strengthening at the interface of the GS and CG matrix was gradually reduced with increasing pre-strain due to the weakening of the interaction at the interface. Microstructural observations at the interface between the GS layer and the CG matrix revealed that more dislocations and twins were activated during pre-strain in the CG matrix having GS constraints than that of the CG matrix without GS constraints. The present work provides important insights on the interaction between constituent layers, in terms of the mechanical response and microstructure evolution.
10.1016-j.jmrt.2023.12.073	-1		This review provides an overview of Cu-Ni-Sn alloys, which have great advantages as a potential substitute for beryllium bronze. The characteristics of spinodal decomposition in Cu-Ni-Sn alloys are thoroughly discussed by conducting a comprehensive analysis of thermodynamics and the phase diagram. The traditional casting process for Cu-Ni-Sn alloys is subject to several limitations, including segregation during solidification as a primary constraint. Another significant limitation is the occurrence of discontinuous precipitation during aging. Thus, the strategies to overcome these limitations are further elaborated. Commonly used methods include thermalmechanical processing and composition design. Finally, the application of Cu-Ni-Sn alloys in friction and corrosion is discussed. The purpose of this review is to provide a comprehensive summary of the research progress and significant limitations encountered in Cu-Ni-Sn spinodal alloys. This includes a discussion of traditional casting methods as well as novel preparation techniques. The aim is to serve as a valuable reference for the development of new manufacturing methods and the future advancement of Cu-Ni-Sn spinodal alloys.
10.1016-j.jmrt.2023.12.095	-1		The Cu-Ge solid solution alloys have a limited color range and relatively low strength due to its limitation of Ge solubility for a solid solution alpha-Cu phase at room temperature. To extend chromatic color range and to improve mechanical properties of Cu-Ge solid solution alloys, the Cu-Ge alloys with relatively higher Ge content than solubility limit on equilibrium state were fabricated by induction casting. The as-cast Cu-Ge alloys with 7-10 at. %Ge exhibited dual-phase structure composed of alpha-Cu and zeta-Cu17Ge3 phases with dendritic structure. By annealing at 700 degrees C for various times and followed quenching processing, the alloys successfully transformed into the supersaturated alpha-Cu single-phase structure. To confirm the color difference between the supersaturated single alpha-phase alloys with a high Ge content and the as-cast single alpha-phase alloys with low Ge content, the reflectivity analysis, CIE L*a*b* color space system, and color difference indicator were used. As a result, it was confirmed that there was a distinct color difference between supersaturated single alpha-phase alloys and as-cast single alpha-phase alloys, and the reflectivity and color difference of the alloys significantly depended on Ge content. Moreover, the Vickers hardness of as-cast and solution treated single alpha-phase alloys highly improved with an increase of Ge content. The influence of Ge content on phase formation, chromaticity and mechanical properties of solid solution Cu-Ge alloys was systematically discussed.
10.1016-j.jmrt.2023.12.105	-1		Cu-Fe composite is a promising candidate for electromagnetic shielding material, while it exhibits poor corrosion resistance due to the different corrosion potential of Fe particles and Cu matrix. In this study, a Cu-Fe composite was processed by multi-directional compression. The effect of multi-directional compression on the mechanical properties of the Cu-Fe composite was evaluated by the tensile test, and the effect of multi-directional compression on the corrosion properties was evaluated by the weight loss test and electrochemical measurement. After 12 compression passes, the yield strength of the Cu-Fe composite is more than two times higher than that of the initial state, and the corrosion rate decreases to nearly half compared to the initial state. Microstructure examination reveals that high density of twin boundaries were generated by multi-directional compression, which could effectively refine the grain size of Cu matrix and improve the strength of Cu-Fe composite. In addition, twin boundaries would reduce the Volta potential difference between Cu matrix and Fe particles, which could effectively inhibit galvanic corrosion, finally leading to a high corrosion resistance of the Cu-Fe composite.
10.1016-j.jmrt.2023.12.174	14	strength; properties; conductivity; electrical; mechanical; cu-; grain; mpa; electrical conductivity; aging; precipitation; phase; mechanical properties; tensile; phases	For atmospheric melting cast Cu-15Ni-8Sn alloy, hot extrusion tests were conducted on ingots of Cu-15Ni-8Sn alloy with varying extrusion ratios (5, 12 and 16) following homogenization and annealing. The investigation employed mechanical property tests, scanning electron microscopy and transmission electron microscopy to analyze the mechanical characteristics, dynamic recrystallization and twinning behaviors of the alloys subjected to different extrusion ratios. The findings revealed a reduction in the average grain size of the alloy as the extrusion ratio increased. The alloy undergoes dynamic recrystallization during hot extrusion, and the degree of recrystallization of the alloy escalated with higher extrusion ratios. The alloy underwent completely recrystallized at an extrusion ratio of 16, primarily driven by discontinuous dynamic recrystallization (DDRX). In addition, the alloy generated twins during the DRX process, and the twin boundaries provided favorable sites for the nucleation of DRX grains, which promoted the DRX of the alloy. Notably, at an extrusion ratio of 16, the alloy demonstrated impressive mechanical properties, with an ultimate tensile strength of 836 MPa and an elongation of 13.5 %. These results presented a substantial enhancement, showcasing a 54 % increase in the extruded ultimate tensile strength and a 350 % increase in the elongation compared to that of the alloy in the homogenized annealed state.
10.1016-j.jmrt.2023.12.180	-1		Nb-lean Cu-Cr-Nb alloys have been widely applied in electrical industries as the structural conductive material owing to their excellent combination of the mechanical and electrical properties at room temperature. In this work, the influence of temperature during fast sintering and post-heat treatment strategies on the precipitate evolution and room temperature mechanical properties of the Cu-3Cr-0.5Nb (wt%) alloy was investigated. The increasing sintering temperature will improve the density and mechanical properties of the alloy without any obvious grain growth during this non-equilibrium process, while the post-aging at lower and higher temperatures can effectively control the formation and coarsening process of the Cr-based precipitates. Systematic characterization was then conducted on the microstructural evolution, especially the altering precipitates' size and distribution, in the alloy at both as-sintered and the aged conditions, which is correlated to its room temperature tensile properties. Lower aging temperature will induce the nucleation of the new Cr2Nb precipitates without causing a significant coarsening of the existing precipitates like aging at higher temperature. Therefore, the lowtemp. aged sample exhibits the highest tensile strength and elongation due to the enhanced Orowan strengthening mechanism induced by its unique precipitate microstructure.
10.1016-j.jmrt.2023.12.286	14	strength; properties; conductivity; electrical; mechanical; cu-; grain; mpa; electrical conductivity; aging; precipitation; phase; mechanical properties; tensile; phases	In this work, the high throughput sample of Cu-0.6Cr-xZr (x = 0-0.18 wt%) alloy was prepared using spark plasma sintering. The influence of Zr concentration on the microstructure and properties of Cu alloys were investigated through advanced characterization technique. The findings reveal that the Zr element concentration in the Cu alloy exhibits a gradient distribution after aging treatment at 500 C. Some Zr elements precipitate as Cu2Zr phase at a certain Zr concentration of 0.14 wt%. The alloy's hardness increases, while its conductivity decreases with the Zr concentration increasing, attributed to the impediment of dislocation and electron movement caused by solid solution atoms, grain boundaries, and precipitated phases.
10.1016-j.jmrt.2024.01.096	0	solidification; phase; magnetic; magnetic field; undercooling; field; liquid; separation; peritectic; immiscible; cu-; dendrite; phase separation; microstructure; primary	To facilitate and even complete the peritectic transformation, the ultrasonic vibration (USV) and isothermal treatment were applied to the solidification process of Cu-70Sn alloy. It was found that the peritectic transformation was difficult to carry out due to the limited atomic diffusion under the normal solidification condition. With the single isothermal treatment, the peritectic transformation could be enhanced to some extent, with a small amount of eta phase (Cu6Sn5) formed relying on the coarse elongated primary e phase (Cu3Sn), but the further prolongation of isothermal time led to the abnormally coarsening of microstructure. When the molten alloy was subjected to 1500W USV and 30 min isothermal treatment, the peritectic transformation was dramatically facilitated. The ultrasonic -induced effects of cavitation and acoustic streaming play an important role in the remarkable reduction in the curvature radius of primary e phase, thereby enhancing the diffusion of Sn solute atoms from the liquid phase to the interior of e phase at the following isothermal stage. Accordingly, the transformation degree of e phase to eta phase was increased up to 77 %, and there was a high volume fraction of primary e phase could thoroughly complete the peritectic transformation.
10.1016-j.jmrt.2024.01.135	-1		Fatigue failure under cyclic deformation remains longstanding challenge in the flexible interconnect for the long term application. In this study, we design Cu-Ag alloy interconnects with excellent fatigue resistance by adopting nanovoid structures acquired by a simple post-annealing process. Nanovoids are generated during Ag agglomeration in the Cu matrix because of the low solubility of Ag in Cu, which enhances the fatigue property of a Cu-Ag alloy deposited on a polyimide film. The effect of high-density nanovoids located at the triple junction of the Cu and Ag grain boundaries on the mechanical fatigue lifetime is investigated by microstructure analysis (HAADF, HR-TEM and ASTARTM-coupled TEM). The fatigue damage of the Cu-Ag alloy has been observed to originate from grain boundary decohesion, unlike typical long fatigue cracks and extrusions. This can be attributed to the uniform distribution of nanovoids, which leads to stress concentration relief and consequently reduces the level of deformation.
10.1016-j.jmrt.2024.01.165	-1		This study explores the effects of hot rolling with a shortened process on the microstructure and properties of Cu-3Ti alloy compared to the traditional multi -pass forming, and the finite element simulation was used to predict the experimental results. At the same time, the residual stress elimination model was used to provide prediction and reference for the relaxation of residual stress during the alloy annealing process. The residual stress of hot rolled samples through the shortened passes is reduced by an average of about 6.7 % after the appropriate annealing treatment, and accompanied by an obvious increase in the yield and tensile strengths compared to that of the traditional multi -pass forming. At the same time, this hot rolled sample by 90 % reduction with 9 passes contains a 45.7 % proportion of high -angle grain boundaries due to the occurrence of extensive dynamic recrystallization, which remains a good consistence with the higher strength under this condition.
10.1016-j.jmrt.2024.01.181	-1		The effects of equal channel angular pressing (ECAP), multiple cryogenic rolling and aging treatment on the microstructure, mechanical properties, and electrical conductivity of Cu-1Cr-0.1Zr alloy were investigated. The results showed that multi-stage deformation and aging (ECAP at ambient temperature + primary cryogenic rolling 50 % + 450 degree celsius aging for 1h + secondary cryogenic rolling 80 % + 150 degree celsius aging for 1h) can lead to the rational comprehensive performance of Cu-1Cr-0.1Zr alloy with tensile strength of 730 MPa and electrical conductivity of 75.5 % IACS. The microstructure characterization revealed that in the Cu-1Cr-0.1Zr alloy a subject to the multistage deformation and aging, there ultrafine grains, nanotwins, nanoprecipitates and micrometer precipitates constituted the nanostructured state. The increase in tensile strength was mainly attributed to fine grain strengthening and precipitation strengthening, followed by dislocation strengthening due to low temperature deformation. The ECAP resulted in the refinement of grain, and the increased dislocation density. The following primary cryogenic rolling refined the grains up to ultrafine-grained (UFG) size and created nanotwins. The introduction of nano-precipitated phases by intermediate aging pinned dislocations and impeded the motion of dislocation entanglements, allowing the alloy to achieve higher strength . Multi-stage deformation and aging resulted in a higher density of twin boundaries in the nanostructure and dilute solid solution in comparison with one stage treatment. These microstructural features were responsible for the excellent electrical conductivity.
10.1016-j.jmrt.2024.01.225	8	hot; deformation; strain; strain rate; dynamic; hot deformation; recrystallization; dynamic recrystallization; flow; rate; flow stress; compression; constitutive; degrees; stress	The hot deformation behavior of the solutionized Cu-15Ni-8Sn alloy is investigated by hot compression tests at temperatures of 750-900 C-degrees and strain rates of 0.001-1.0 s(-1). The flow stress curves of the alloy are analyzed, and the constitutive equations are developed to predict the flow behavior of the alloy. In addition, the optimal deformation conditions are proposed through the constructed hot processing map and microstructure analysis, revealing the impact of the deformation mechanism under different deformation parameters on the microstructure evolution. The results show that temperature and strain rate have a great influence on the hot deformation of the alloy. The strain-compensated constitutive equation can well predict the peak flow stress of the alloy, with a correlation coefficient of 0.993 between experimental and predicted values. The high power consumption region is mainly caused by dynamic recovery and partial dynamic recrystallization, while flow localization is the main reason for the appearance of the unstable region. The optimum hot processing conditions for the alloy are at a temperature range of 750-780 C-degrees and the strain rate is 0.001-0.0025 s(-1).
10.1016-j.jmrt.2024.02.028	14	strength; properties; conductivity; electrical; mechanical; cu-; grain; mpa; electrical conductivity; aging; precipitation; phase; mechanical properties; tensile; phases	Herein, an alloy Cu-1.16Ni-0.36Cr with outstanding high-temperature mechanical properties was obtained, and the underlying mechanism was discussed. The properties were compared with those of commercial Cu-Fe-P alloys. The alloy exhibited a high-temperature softening temperature of 674.7 degrees C. Tensile tests conducted at high temperatures revealed that at 700 degrees C, the alloy maintained a tensile strength of 131.3 MPa, whereas Cu-Fe-P alloys only exhibited a tensile strength of 58.7 MPa. Microstructural analysis revealed the formation of nanoscale Ni3Cr7 precipitates near fractures at high temperatures, with the average size being approximately 10 nm. These nanoscale precipitates hindered the coarsening of Cr particles and dislocation slips, forming dislocation rings and substantially enhancing the high-temperature mechanical properties of the alloy. Furthermore, the nanoscale precipitates considerably impeded the growth and expansion of recrystallized grains. After a high-temperature treatment at 700 degrees C, a portion of the microstructure in the alloy remained stretched, with the small -angle grain boundaries being high (68.2%) and the recrystallization degree being only 50.4%.
10.1016-j.jmrt.2024.02.153	-1		Cu-Ag alloy wire with different deformations and Ag contents of 1%, 2%, and 4% are prepared using vacuum continuous casting technology combined with cold drawing and intermediate annealing processes. The evolution of microstructure, electrical properties, and mechanical properties of the Cu-Ag alloy wire is investigated, and a relationship model between wire diameter, Ag content, and alloy wire properties is established. The results showed that the directionally solidified billets exhibited good elongation and are suitable for drawing fine wire. As the Ag content increased, the twinning content inside the Cu-Ag alloy wire also increased significantly. It is found through Strain++ characterization that there is non -uniform deformation within the wire, and the tensile and compressive strains that exist interactively tend to aggregate within the twins. The properties of the Cu-Ag alloy wire with different diameters varied significantly at different stages of deformation, showing a pronounced size effect below 1 mm. With decreasing wire diameter or increasing Ag content, the DC resistance, resistivity, and tensile strength of the Cu-Ag alloy wire gradually increased, while the conductivity decreased. The effect of Ag content on elongation is not significant. Statistical analysis revealed that the established performance model had high predictive accuracy and could provide references for the optimization of production processes for Cu-Ag alloy wire.
10.1016-j.jmrt.2024.03.075	-1		The increasing demand for materials possessing enhanced mechanical strength, high thermal conductivity, and excellent electrical properties has grown significantly. Cu-matrix composites, especially Cu- Ni, present a promising candidate to fulfill these demands. In this study, Cu-Ni composites were successfully synthesized using powder metallurgy with various additions (0-1.5 wt%) of Yttria (Y2O3)-reinforcement aiming to enhance their mechanical, thermal, and electrical properties. The microstructural investigations demonstrated a uniform distribution of Y2O3 particles and a slight increase in porosity of the Cu-Ni matrix. The Cu-Ni composites with 1.5 wt% Y2O3 showed the presence of Cu2NiZn intermetallic compounds, potentially harming their physical and mechanical properties. Y2O3-reinforcement significantly increased the hardness and led to a moderate rise in the yield and ultimate compressive strengths. The results indicated that the Cu-Ni matrix without Y2O3-reinforcement had the highest coefficient of thermal expansion, which decreased with the addition of Y2O3, potentially leading to improved thermal properties of Cu-Ni composites. This study puts an emphasis on the importance of Y2O3 particles dispersion and on the extent of porosity in enhancing the thermal and mechanical properties of Cu-Ni composites.
10.1016-j.jmrt.2024.03.098	-1		Cu-3Zr alloy was prepared by powder metallurgy and two-stage thermomechanical process, and the microstructure evolution and properties were investigated. The results show that the microstructure of as-sintered Cu-3Zr alloy is consisted of the coarse Cu-Zr intermetallic compounds and equiaxed Cu grains. After extrusion, the second phase is smaller in cross section, while deformation texture of the Cu matrix can be seen from longitudinal section. After further drawing, the Cu grains are elongated and the Cu-Zr intermetallic phase is broken into fine particles. The yield strength (YS), ultimate tensile strength (UTS) and electrical conductivity are 593 MPa, 684 MPa, and 74%IACS, which are respectively increased by 38%, 34% and 21% as compared to the as-sintered Cu-3Zr alloy. Phase analysis and microstructural characterization demonstrate that the Cu5Zr, Cu8Zr3, and Cu10Zr7 precipitates are uniformly distributed in the Cu matrix. Cu5Zr/Cu and Cu8Zr3/Cu are combined in the form of coherent relation. Cu10Zr7/Cu are combined in the form of semi-coherent relation. The enhanced mechanical properties can be attributed to the multiple synergistical strengthening effect. The elongated Cu grains and fine Cu-Zr precipitation phases block the movement of dislocation, resulting in the remarkable enhancement of strength . Moreover, the elongated Cu grains can provide fast channel for the electron transport, giving rise to simultaneous increase of the electrical conductivity.
10.1016-j.jmrt.2024.03.109	6	grain; deformation; strain; strength; dislocation; cu-; tensile; size; ecap; grain size; sfe; ductility; hardening; high; stress	The influence of the grain sizes ranging from 23.4 to 69.2 mu m on mechanical properties of Cu-3wt%Ag-0.5 wt% Zr thin sheets was investigated by conducting uniaxial tensile experiments at room temperature (RT 298 K) and cryogenic temperature (CT 77 K). At RT, the strength and ductility of the sheet decreased as the grain size increased, and the size effect on flow stress was observed when the ratio of thickness to grain size ( t / d ) was less than 4.5. At CT, the sheet exhibited excellent strength and ducility, accompanied by a reduction in the size effect on flow stress. GND distribution maps showed that the average GND density of grains in the sample surface (surface grains) was lower than that of grains in the core of the sample (core grains). As the distance from the grain boundary increased, the GND density decreased. A constitutive model was developed for Cu-3wt%Ag-0.5 wt%Zr thin sheets based on the dislocation accumulation and recovery process, which was able to predict the effects of grain size and deformation temperature on the flow stress and GND evolution in Cu-3wt%Ag-0.5 wt% Zr thin sheets. This constitutive model indicated that CT not only inhibited the GND recovery process but likewise promoted the GND accumulation process. The established constitutive model revealed that the ratio of SSD density to GND density increased with increasing strain. The total dislocation density and GND density of samples deformed at CT was higher than those of samples deformed at RT.
10.1016-j.jmrt.2024.03.122	16	wear; composite; composites; powders; milling; particles; powder; wt; sliding; friction; hardness; matrix; mechanical; surface; properties	Shape memory and super elasticity are two outstanding properties of Cu-Al-Mn SMAs together with additional copper-based shape memory alloys that make them superior to NiTi alloys. It's quite hard to machine Cu-Al-Mn SMA. The machinability properties of Cu-Al-Mn SMAs during Wire Electrical Discharge Machining (WEDM) were experimentally investigated using molybdenum wire as the electrode material. Material Removal Rate (MRR) and Surface Roughness (SR) are two machining qualities that are studied in relation to the combinational values of pulse time (Ton), pause time (Toff), and peak current (Ip), which are selected as the changeable input process factors. From the experimental investigation, it was found that both MRR and Ra values were increased with an increase in pulse on time(Ton), pulse off time(Toff), and peak current (IP)values. Because the wire electrode contains maximum current under these conditions, it is easy to remove more material at the tool and work material interface, resulting in moderate surface finish . Surface quality was higher on samples machined at low energy input than it was on samples machined at high energy input. This SEM micrograph clearly shows that a lower pulse on time produces a superior surface quality.SEM images and the analysis of the machined surface morphology on the surface of the CAM7 alloy clearly showed that the machined surface of the alloy had a lower surface roughness value at a lower Ip-2A and was associated with a higher surface roughness value at a higher Ip6A, as well as a lot of uncleared debris and blow holes.
10.1016-j.jmrt.2024.04.033	14	strength; properties; conductivity; electrical; mechanical; cu-; grain; mpa; electrical conductivity; aging; precipitation; phase; mechanical properties; tensile; phases	In this study, Cu-9Ni-6Sn-xCr alloys (x = 0, 0.3, 0.6, or 1.0) were designed and prepared. The influence of Cr content on the microstructure, the precipitation behavior, and the mechanical properties of the alloys was systematically investigated. The results show that the Cu-9Ni-6Sn-0.6Cr alloy exhibits outstanding mechanical properties and higher level electrical conductivity after aging at 400 degrees C for 8 h: The peak-aged hardness reaches 323.6 +/- 8.4 HV, with a tensile strength of 876.4 MPa and an electrical conductivity of 12.59 +/- 0.33% IACS. These excellent comprehensive properties of Cu-9Ni-6Sn-0.6Cr alloy are attribute to the refinement effect and the precipitation of DO22 phase within the Cu matrix grains. Further analysis reveals that the addition of an appropriate amount of Cr refines the microstructure of the alloy and promotes the precipitation of the DO22 phase. At the same time, Cr also suppresses the precipitation of the DO3 phase at grain boundaries, achieving an excellent combination of plasticity, electrical conductivity, and strength . This work suggests that the potential application prospects of Cr in the multi-component design of Cu-Ni-Sn alloy, and the addition of 0.6 wt% Cr can achieve good strengthening effects and provide outstanding comprehensive performance for Cu-Ni-Sn alloys.
10.1016-j.jmrt.2024.04.062	-1		Twins play a crucial role in elucidating the structure and deformation characteristics of materials. However, in materials with low-symmetry crystal structures, solving the twin relationships remains a challenging task. In this study, we propose a general method for determining twin elements K1, eta 1, K2, and eta 2, which are essential for twin analysis. The proposed method involves three main steps: (1) representing misorientation data measured by electron back-scattered diffraction (EBSD) and transmission electron microscopy (TEM) in matrix form, (2) identifying additional 180 degrees rotation elements related to twin elements K1 or eta 1 by traversing all symmetrically equivalent misorientations, and (3) using a minimum and crystal structure-dependent uniform shear as the constraint to determine the other twin elements (K2 and eta 2). By combining the experimental data and the proposed method, we systematically analyze the complex twin relationships of Cu-Zn-Al shape memory alloys (SMAs) with monoclinic martensite (M18R). This methodology has been demonstrated to be effective and possesses broad applicability.
10.1016-j.jmrt.2024.04.075	-1		It is difficulty to utilize the pore formation function of TiH2 in the copper-based matrices of diamond tools due to the mismatch between dehydrogenation temperature and densification temperature. In this study, Cu-Sn-Ti porous materials were prepared by innovative powder pre-processing and two-step sintering processes. The results showed that Cu-Sn-TiH2 powder with uniform composition, high alloying degree and high TiH2 retention rate were achieved by optimizing pre-processing parameters. During the subsequent sintering process, Sn and Ti elements were precipitated from the copper matrix, leading to the formation of Ti-rich phases at grain boundaries and pore walls. Simultaneously, pores with higher sphericity and uniform distribution were formed due to the thermal decomposition of TiH2. The porosity, average pore size, bending strength, and bending elastic modulus of Cu-Sn-Ti porous material were measured as 30.6%, 2.15 mu m, 245 MPa, and 2.23 GPa, respectively. The comprehensive properties were better than the reported results.
10.1016-j.jmrt.2024.04.141	-1		Copper and copper alloy are commonly used to fabricate ship propellers and sealing valves that encounter harsh corrosion and wear. To improve their service life, Cu coating and Cu-AlN composite coatings with different volume content of AlN (10%, 20%, 30%) were prepared by cold spraying. The investigation focused on analyzing the coatings' microstructure, microhardness, resistance to wear, and corrosion. Results show that the composite coatings with AlN have fewer pores and denser microstructure than the Cu coating. The coating demonstrates a relatively low deposition efficiency, resulting in the attainment of only 3.8 vol% of AlN when the feedstock AlN powder content was 30 vol%. The microhardness of Cu-3.8AlN coating is 159.7 HV, about 53.1% higher than that of Cu coating. The specific wear rate of Cu-3.8AlN coating is reduced by about 73.5% compared to that of Cu coating, measuring at 1.69 x 10-3 mm3/(N center dot m). Compared with other coatings, Cu-3.8AlN has the highest corrosion resistance (Ecorr = -0.199 V, Icorr = 1.2 mu A/cm2, Rct = 3200 Omega center dot cm2). The Cu-3.8AlN coating exhibits superior wear and corrosion resistance among the four coatings, attributed to its highest level of densification and the presence of AlN particles.
10.1016-j.jmrt.2024.04.146	-1		A new method to prepare large Cu-Cr alloy with both high strength and high conductivity has been developed. Cu-Cr billets are produced efficiently by laser additive manufacturing, and the microstructure of the alloy is changed by severe plastic deformation caused by large cold rolling ratio. The strength of the alloy can be significantly increased to 677 MPa by eliminating pores, introducing texture and refining grain. The deformation twins caused by plastic deformation processing make up for the plasticity loss caused by grain refinement. With the increase of density and the deformation of Cr particles, the electrical conductivity of the alloy is increased to 28.7 MS/m. Our findings not only deepen the understanding of laser additive manufacturing of highly reflective metals, but also provide a new idea for the preparation of high -strength and high -conductivity Cu alloy workpieces.
10.1016-j.jmrt.2024.04.148	-1		In this paper, three kinds of Cu-Cr2O3 composites with different particle sizes were prepared from Cu-0.67 wt% Cr atomized alloy powder by supercritical water liquid phase in-situ oxidation (SW-LIO) through reduction and spark discharge plasma sintering (SPS). The structure and properties of the composites were systematically analyzed by X-ray diffractometer (XRD), scanning electron microscope (SEM), energy spectrometer, transmission electron microscope, electron backscattering diffraction, universal material testing machine, microhardness tester, eddy current conductometer, friction and wear testing machine, etc. The results show that Cr2O3 particles are evenly distributed in Cu matrix composites. The hardness of composites improved by 19% as the particle size decreased, while the tensile strength and electrical conductivity first increased as the particle size is refined. Meanwhile, the deformation behavior research is carried out, and the mechanical properties and electrical conductivity of composites are enhanced as the deformation amount increases.
10.1016-j.jmrt.2024.04.150	14	strength; properties; conductivity; electrical; mechanical; cu-; grain; mpa; electrical conductivity; aging; precipitation; phase; mechanical properties; tensile; phases	Cu-15Ni-8Sn alloy is commonly utilized in various applications because of its exceptional strength, elasticity, and softening resistance. Ti microalloying has been employed to enhance the mechanical properties of Cu-15Ni-8Sn alloy. By adding 0.5 wt% Ti, the peak-ageing tensile strength, microhardness, and elastic modulus of the Cu-15Ni-8Sn alloys reach 1401.3 MPa, 479.3 HV, and 154.7 GPa, respectively, representing the greatest comprehensive performance reported in previous literature. Additionally, the Ti microalloying significantly enhances the softening resistance of Cu-15Ni-8Sn alloys. After ageing at 400 degrees C for 10 h, the tensile strength of the Cu-15Ni-8Sn-0.5Ti alloy decreases by only around 150 MPa, whereas the alloy without Ti addition experiences a decrease close to 350 MPa. Quantitative analysis reveals that the observed improvements can be attributed to the Ti microalloying inhibiting the dislocation annihilation and the formation of discontinuous precipitation during the ageing process, while simultaneously promoting the precipitation of Ni 3 Ti. This study provides a theoretical basis for preparing a high -performance Cu-15Ni-8Sn alloy by microalloying.
10.1016-j.jmrt.2024.04.208	8	hot; deformation; strain; strain rate; dynamic; hot deformation; recrystallization; dynamic recrystallization; flow; rate; flow stress; compression; constitutive; degrees; stress	Compression tests of the Cu-1.5Ti and Cu-1.5Ti-0.5Fe alloys were carried out using the Gleeble-1500D hot deformation simulator. The deformation temperature was 750-900 degrees C and the strain rate was 0.1-0.003 s -1 . The Cu-1.5Ti-0.5Fe alloy clearly shows higher rheological stress and displays dynamic recovery and dynamic recrystallization characteristics under the same deformation conditions. The constitutive equations of the alloys were established. The activation energy of the Cu-1.5Ti alloy was 341.76 kJ/mol, which increased to 378.03 kJ/ mol with the addition of 0.5 wt% Fe. After 750 degrees C and 0.003 s -1 deformation the Cu 4 Ti phase precipitated in Cu1.5Ti alloy. Adding 0.5 wt% Fe caused dynamic recrystallization during hot deformation. The hot-deformed Cu1.5Ti-0.5Fe alloy had more dislocations and finer grains with Cu 4 Ti and Fe 2 Ti precipitated phases.
10.1016-j.jmrt.2024.04.221	-1		Hardness and Young's modulus are critical indicators in the design of innovative Cu-Ni-Sn-Al alloys with desired elastic and strength properties. In this study, the composition-dependent hardness and Young's modulus in the fcc Cu-Ni-Sn-Al alloys were determined using high-throughput experiments, the CALPHAD (CALculation of PHAse Diagrams) approach, and machine learning (ML) model. By combining the diffusion-couples tool, nanoindentation, and electron probe microanalysis (EPMA) techniques, the 341 sets of composition-related hardness and Young's modulus in the fcc Cu-Ni-Sn-Al system, as well as its sub-binary and sub-ternary systems, were effectively determined. These measured data were subsequently utilized to establish the relationship of Young's modulus and hardness with respect to composition in the fcc Cu-Ni-Sn-Al system through the combined application of CALPHAD and back propagation (BP) artificial neural network machine learning models. A comparison between the two approaches revealed that the ML method achieves higher accuracy in ternary and quaternary alloys compared to the CALPHAD method. The impact of alloying elements on the values of hardness and Young's modulus was analyzed, demonstrating that the Ni content has the largest effect on hardness, while the Young's modulus increases with addition of Ni but decreases with the addition of Al and Sn. Finally, the effects of solute elements on the nanomechanical properties of aged Cu1-x(Ni3Sn)x and Cu-9Ni-6SnxAl alloys were examined.
10.1016-j.jmrt.2024.05.143	-1		Multi-componentization can further improve the heating resistance of Cu-Ni-Al alloys, enabling them to withstand more demanding situations. Unfortunately, the limited researches have been done on the wear and corrosion resistance of the heat-resistant Cu-Ni-Al alloys, resulting in the lack of relevant evidence in the practical application. In this work, a comparative study of differential types of trace element, Si (the stronger enthalpy interaction element), Sn (the weaker enthalpy interaction element) Cr or Zr (grain boundary strengthening element), effects on microstructure, wear and corrosion resistance will be done, Furthermore, the effect of different trace elements on the surface electron work function and electrochemical behavior of Cu-Ni-Al alloys is reflected by SPM surface potential model. The results indicate that the precipitation of dual nano-phase and accelerated precipitation of gamma ' phase can be realized through the addition of Si, Sn, Cr and Zr, in which the value of delta gamma-gamma ' increase sharply after adding Si and it is not conducive to the preservation of cuboidal gamma ' phase. The addition of Si, Cr and Zr can improve electron work function distribution and mechanical property, wear, and corrosion resistance of the alloys, in which Si is more conducive to the improvement of wear resistance and mechanical properties of the alloy, while the alloy with Cr and Zr shows the excellent corrosion resistance. The addition of Sn will weaken the enthalpy interaction of the alloy system, reduce the electron work function of the alloy, and have adverse effects on the wear and corrosion resistance of the alloy.
10.1016-j.jmrt.2024.05.151	-1		The magnetic immiscible copper matrix alloys are extensively industrial applications due to their comprehensive properties such as high strength, high conductivity, high thermal conductivity and excellent magnetic permeability. Here, we investigated the effects of the addition of Co and Al elements on the microstructural evolution of magnetic Cu-Fe alloys (CFAs) and comprehensive properties after annealing under the static magnetic field (SMF). The results show that the microalloying was effective in enhancing the mechanical and magnetic properties but negative for the electric conductivity. The addition of Co element significantly suppressed the grains recrystallization of CFAs during the annealing process and improved the thermal stability of CFAs. Al elements homogeneously dispersed in the sample. SMF facilitated the nucleation and precipitation processes of the secondary precipitated particles in the Cu-rich matrix through the introducing the extra magnetic Gibbs free energy and also promoted the structural transformation of the secondary precipitated particles from FCC to BCC. This work indicates that SMF can be effectively used to modify the magnetic materials with exceptional comprehensive properties during the solid state phase transformation process. It also provides valuable guidance for the development of novel materials with superior comprehensive performance.
10.1016-j.jmrt.2024.05.193	14	strength; properties; conductivity; electrical; mechanical; cu-; grain; mpa; electrical conductivity; aging; precipitation; phase; mechanical properties; tensile; phases	As the marine industry progresses, copper -containing metallic materials that possess both high strength and ductility are demanding. Traditional copper alloys used in marine environment face challenges regarding inadequate strength and corrosion resistance. In the present work, cold rolling and subsequent high -temperature annealing processes were employed to the Cu 1.2 NiMnFe 0.5 Cr 0.5 Al 0.2 high -entropy alloy. This alloy exhibited remarkable mechanical properties, including a yield strength (YS) of 530 MPa, ultimate tensile strength (UTS) of 913 MPa, and a relatively high fracture elongation (EL) of 37.7%. After subsequent aging treatment at 400 degrees C, spinodal decomposition occurred within the matrix, leading to enhanced strength . The decomposed microstructure was comprehensively characterized, and the strengthening mechanism was analyzed. Notably, the sample aged for 6 h exhibited a YS of 701 MPa and an EL of 21.8%. The present HEAs exhibit superior mechanical properties compared to traditional copper alloys and other Cu -containing HEAs, when considering both strength and ductility. Furthermore, these alloys demonstrated exceptional corrosion resistance and a favorable copper ion release rate in 3.5 wt% NaCl solution. This work introduces an innovative class of advanced alloys and offers a strategic approach to alloy design for marine applications.
10.1016-j.jmrt.2024.05.212	2	corrosion; surface; film; electrochemical; films; spectroscopy; layer; current; solution; potential; resistance; composition; x-ray; ions; showed	The effect of sulfides on the pitting corrosion behavior and film chemistry of 70/30 copper -nickel alloys in aerated seawater was investigated. Sulfides in seawater prevent the formation of protective oxides on the surface of the alloy and alter the morphology and composition of the corrosion products. It results in the corrosion product film consisting of the double layer structure of the loose and porous sulfide -containing outer layer and the dense inner layer. This double -layer structure of the corrosion product film can't alleviate corrosion, but instead accelerates the development of pitting corrosion. The statistical analysis method is used to study the corrosion process of 70/30 copper -nickel alloy in sulfide -containing environment. This work records the trend of pitting corrosion towards the horizontal and longitudinal directions.
10.1016-j.jmrt.2024.05.223	12	thermodynamic; ternary; phase; data; experimental; equilibria; phase equilibria; liquid; binary; experimental data; calculated; phases; literature; model; calphad	The Cu-Cr alloys with magnesium and yttrium exhibit appealing high -strength and high -conductivity (HSHC) characteristics. Anticipated contributions to the design of HSHC copper alloys include new insights from understanding the phase equilibria, solidified microstructure, and thermodynamics of the Cu-Cr-X (X = Mg, Y) systems. Five Cu-Cr-Y alloys and three Cu-Cr-Mg alloys were melted through arc melting and powder metallurgy, respectively. An analysis was conducted on the primary phases and solidification path of the as -cast Cu-Cr-Y alloys. Five three-phase regions in the Cu-Cr-Y system and three in the Cu-Cr-Mg system at the isothermal sections of 673 K were identified using XRD and EPMA. No ternary compound was discovered among either of these systems. The agreement between the experimental data and the calculated isothermal sections and liquidus projection derived from the thermodynamic description of the binary systems is quite good. The investigation on phase equilibria in Cu-Cr-X (X = Mg, Y) systems in this study helps in developing the thermodynamic database for multi -component copper alloys.
10.1016-j.jmrt.2024.05.231	-1		Without homogenization or special micro-alloying treatment, the tensile strength and electrical conductivity of a commercial Cu-Ni-Si alloy can achieve 813 MPa and 51.2% IACS, respectively. The excellent combination properties were achieved by regulating the thermomechanical treatment to obtain a critical status of precipitates and dislocation densities. Although a short time pre-aging process can increase the mechanical strength, the electrical conductivity was not dramatically enhanced due to the limited precipitation process. A long-time preaging process or a too-high density of dislocations is not favorable to the nucleation of new precipitates, which, instead, causes the coarsening of pre-precipitates, resulting in a limited increase in strength . A critical dislocation density can be determined to boost the nucleation sites of precipitates to simultaneously maximize the mechanical and electrical properties of Cu-Ni-Si alloys. The obtained mechanical and electrical properties can meet the requirements for very large-scale lead frames. Thus, our investigation not only provides a new route for manufacturing high-performance Cu-Ni-Si alloys but also new insights into the role of dislocations in enhancing the mechanical properties of age-hardening alloys.
10.1016-j.jmrt.2024.06.142	15	aging; strength; conductivity; electrical conductivity; electrical; mpa; treatment; strengthening; degrees; cu-; cold; precipitation; tensile strength; tensile; iacs	The Cu-Cr-Zr-Nb alloy bars were prepared by vacuum melting, hot forging, solution treatment, and drawing. The effects of aging processes on the microstructure, texture, mechanical properties and electrical conductivity of the alloy were studied, and the precipitation kinetics was analyzed. Besides, the effect of adding Nb to the Cu-Cr-Zr alloy was simulated by the first-principles calculation. The results showed that when the aging temperature increased from 400 degrees C to 460 degrees C, Cube texture and Brass texture were transformed into Copper texture. The Cu-Cr-Zr-Nb alloy exhibited superior comprehensive properties such as a hardness of 84.3 HRB, a tensile strength of 520 MPa, an elongation of 19.0 %, and an electrical conductivity of 83.5 International Annealed Copper Standard (%IACS) after being aged at 460 degrees C for 4 h . The precipitation kinetics and electrical conductivity equations under different aging temperatures were established, and the precipitation activation energy of 24 kJ/mol was obtained. Moreover, the precipitation process of the alloy was also described by the Avrami empirical equation. It was found that the reaction mechanism of the alloy changed from nucleation and growth to one-dimensional diffusion as the aging temperature increased from 400 degrees C to 520 degrees C. It was also confirmed that Nb and Cr formed the Cr2Nb compound according to the first-principles calculation.
10.1016-j.jmrt.2024.06.160	-1		Copper matrix composites with dual-scale particles were fabricated through casting with reaction. Ultrasonic vibration has been successfully introduced into the melt at about 1523 K while the microstructural development and mechanism of copper matrix composites with high-performance through a novel method of casting with ultrasonic vibration treatment are investigated. When ultrasonic vibration is applied, the distribution of microscale particles is greatly improved. Primary Cr phase convents to non-dendrite and large aggregates of ZrB2 particles are disrupted into small clusters because of acoustic cavitation and acoustic streaming. The ultimate tensile strength and elongation of Cu-1wt%Cr-0.3 wt%Zr-1wt%ZrB2 composite in as-cast state were 321 MPa and 14.37 %, recording a 28.4 % and 14 % increment respectively compared with the sample without treatment. After solution treatment, deformation and aging subsequently, the uniform distribution of reinforcements also decreases the average transverse grain thickness and increases the dislocation density which improve the comprehensive properties.
10.1016-j.jmrt.2024.06.197	-1		Six Cu-Ni-Si-Cr alloy composites are prepared by explosive welding with the designed parameters. Wavy interface containing the melted pockets and shrinkage cracks is always observed, refining the grains to just several micrometers with the localized deformation. Resultantly, the interface regions show higher hardness and yield strength than elsewhere, reaching HV 190 and over 400 MPa, respectively, but their plasticity is less than half that of the base-plate parts. Theoretical analysis successfully relates the area of the total disrupted regions including the interfacial molten and wavy zones in the composites linearly to the flyer-plate thickness (hf) and collision angle (beta) as hf sin2 beta . For the composite fabricated at an impact velocity and angle of 310 m/s and 8.0 degrees, respectively, strengthening mechanism calculation for its interface part reveals that grain boundary, dislocation and solid solution hardening are most effective and contribute 68 MPa, 370 MPa and 39 MPa individually, making the dislocation hardening dominant for the enhanced strength .
10.1016-j.jmrt.2024.06.231	15	aging; strength; conductivity; electrical conductivity; electrical; mpa; treatment; strengthening; degrees; cu-; cold; precipitation; tensile strength; tensile; iacs	Multistage thermomechanical treatment experiments were conducted on Cu-Ni-Co-Si-Mg alloy strip prepared by the Heating Cooling Combined Mold (HCCM) horizontal continuous casting-cold rolling process. Effects of various heat treatments on the microstructure, mechanical properties, and electrical conductivity of the alloy were studied. The strengthening mechanisms and factors influencing the performance of each process has been analyzed. The tensile strength, yield strength, and electrical conductivity of Cu-Ni-Co-Si-Mg alloy can reach 894 MPa, 855 MPa, and 47.1 %IACS after a third-stage of thermomechanical treatment (TTMT). The cold rolling in first-stage of thermomechanical treatment (FTMT) not only caused work hardening of the alloy but also promoted the precipitation of solute atoms and the growth of second phase particles, limiting the increase in strength . Second-stage of thermomechanical treatment (STMT) effectively hindered the excessive growth of second phase particles in FTMT but shortened recrystallization process. The superior performance of Cu-Ni-Co-Si-Mg alloy after TTMT was attributed to dispersive precipitation of Ni, Co, and Si elements as (Ni, Co) 2 Si phases in the copper matrix, strengthening the interaction between the precipitates and dislocations. A short process of HCCM horizontal continuous casting-cold rolling-thermomechanical treatment was developed to produce a high strength and highly electrically conductive Cu-Ni-Co-Si alloy strip used in lead frames.
10.1016-j.jmrt.2024.07.050	-1		The (3'-Cu4Ti phase is the major strengthening precipitate in Cu-Ti alloys. Previous research indicates that destabilization of the (3'-Cu4Ti phase leads to dissolution of Ti atom from precipitates into the Cu matrix. In the present work, Sc was chosen to be alloying elements in Cu-Ti alloys, since stabilization of the (3'-Cu4Ti phase could be enhanced by formation of (3'-Cu4(Ti,Sc) phase. Experimental characterization combined with firstprinciples calculations were used to evaluate the effect of Sc addition. It was found that the bonding between Ti and Sc atoms in the same sublattice of (3'-Cu4Ti phase increases the diffusion barrier of Ti atoms, and thus dissolution of the (3'-Cu4Ti phase and further nucleation of the (3-Cu4Ti phase were hindered.
10.1016-j.jmrt.2024.07.180	-1		There is currently interest in the development new Cu-Fe alloys with higher Fe content (>5 wt%), a low-cost element. In order to improve electrical, thermal and mechanical properties, there is a need to decrease the size of the Fe-rich phase and improve its distribution, whose possibilities rely on adding alloying third elements and heat treatments. However, the prospect of controlling the size of the phase through dendritic spacing control by means of rapid solidification processes may be feasible and deserves to be explored, as is the case in the present study. The following methods were employed to evaluate the round stepped cast samples of the Cu-20 wt% Fe alloy: centrifugal casting in a Cu mold, optical microscopy, CALPHAD, Scanning Electron Microscopy/ Energy Dispersive Spectroscopy (SEM/EDS), X-ray Diffraction (XRD), Vickers hardness, and compressive tests, in samples corresponding to different coarsening microstructures. Finally, dendritic growth is modelled using the Kirkwood equation. The results demonstrate a promising processing route with control of the secondary dendrite arm spacing (SDAS), whose methodology and modeling can serve as a basis for other alternative processes with the Cu-Fe alloys, allowing suitable size and distribution of Fe phase to be attained. It is further demonstrated that the Kirkwood model is able to match experimental SDAS in both slowly and rapidly solidified Cu-Fe samples. While Fe (BCC) is expected to increase strength, this is only slightly observed in the hardness results for smaller SDAS, as the loads are more superficial. In the case of compressive yield strength, SDAS in the observed range (1.4 mu m-2.2 mu m) is found to have no effect.
10.1016-j.jmrt.2024.07.210	12	thermodynamic; ternary; phase; data; experimental; equilibria; phase equilibria; liquid; binary; experimental data; calculated; phases; literature; model; calphad	The phase equilibria of the Cu-Cr-Ag-Y and Cu-Cr-Ag-Zr systems at 600 and 700 degrees C with a fixed Y and Zr contents of 5.0 at% were extrapolated by CALPHAD (CALculation of PHAse Diagrams) method based on the thermodynamic parameters for the constitutive binary and ternary systems. Twelve Cu-Cr-Ag-Y and six Cu-Cr-Ag-Zr alloys were designed in different phase regions of extrapolated isothermal sections. The phases, phase compositions and microstructures of alloys were experimentally investigated by means of X-ray diffraction (XRD) and scanning electron microscopy (SEM). No quaternary phase was found. The solubilities of the solid solution phases and intermediate compounds were measured. The solidified sequences and microstructures of the Cu-Cr-Ag-X (X = Y, Zr) as-cast alloys were experimentally investigated as well as simulated by Scheil model. The calculated results are in agreement with the experimental data, which indicates the accuracy of thermodynamic databases of the Cu-Cr-Ag-X (X = Y, Zr) systems. The present work lays an important foundation for establishing the thermodynamic database of multicomponent Cu alloys.
10.1016-j.jmrt.2024.08.022	14	strength; properties; conductivity; electrical; mechanical; cu-; grain; mpa; electrical conductivity; aging; precipitation; phase; mechanical properties; tensile; phases	In response to the persistent challenge of optimizing the tribological performance of engineered coatings without compromising material hardness, this study investigates the potential of medium-entropy CrCoNiCu alloy films. Fabricated via sputtering and subsequently aged at 200 degrees C for 24 h, these films are examined for their mechanical and tribological behaviors through nanoindentation and reciprocal sliding wear tests. The primary result reveals that the sputtering fabrication yields a single face-centered cubic phase enriched with stacking faults and twins due to a vapor quenching and an increase in defective nuclei formation. The aging treatment uniquely facilitates the formation of Cu-rich phases, featuring repetitive plate-like structures along twin boundaries, by altering diffusion pathways to enhance diffusivity at the applied low temperature. Remarkably, this process not only increases the hardness of the films by 1.5 GPa but also leads to significant improvements in their tribological performance, with reductions in friction coefficients and wear volumes by 12.1% and 90.1%, respectively. The tribological properties originate with the synergistic effects of precipitation hardening and the lubricating layer inducing the reduction of abrasive wear and inhibition of direct contact between sliding surfaces. These findings illuminate that the CrCoNiCu alloy exhibits an exceptional capacity for superior wear resistance at soft metals, offering a compelling strategy to navigate the traditional trade-off between wear rate and hardness in the design of advanced engineering materials.
10.1016-j.jmrt.2024.08.036	-1		In this work, the effects of the gradient microstructures by surface mechanical attrition treatment (SMAT) on the corresponding tribological properties of the nanoprecipitates strengthened copper alloy was investigated. The nanoprecipitates strengthened copper alloy possesses a decent tribological properties compared with the pure copper and bronze. The SMAT-processed NP&T &T alloy possesses distinctly lower coefficients of friction (COF) than its coarse-grained counterpart throughout the entire frictions. In particular, under a sliding load of 2 N, NP&T &T alloy possesses a lower COF of 0.58 +/- 0.03, approximately 15% lower than that of its homogeneous counterpart. Additionally, the wear volumes, wear rates, and worn surface roughness were approximately 45% lower in the NP&T &T alloy, indicating the superior tribological properties. The macro-, micro-, and atomic-scale friction and wear mechanisms in the worn NP&T &T alloy were systematically determined. The inherent gradient nanostructures could achieve strain delocalization, thereby suppressing surface deformation and improving wear resistance. Wear-induced substructure in the NP&T &T alloy comprises gradient layers mediated by twinning and stacking faults combined with nanocomposite layers, resulting in novel tribological performance characteristics. Thus, combining inherent and newly formed wear-resistant gradient nanostructures is an effective design strategy for high-performance Cu alloys.
10.1016-j.jmrt.2024.08.209	14	strength; properties; conductivity; electrical; mechanical; cu-; grain; mpa; electrical conductivity; aging; precipitation; phase; mechanical properties; tensile; phases	Cu-15Ni-8Sn-xNb alloys (x = 0, 0.2, 0.6 wt%) were prepared using a medium-frequency induction melting furnace. The effect of Nb addition on grain refinement and inhibition of discontinuous precipitation (DP) in Cu-15Ni-8Sn alloys was systematically studied to elucidate the mechanism by which microstructural characteristics contribute to strength improvement. The results indicate that the increase the Nb content from 0 to 0.6 wt% reduces the average grain size of the as-cast alloy from approximately 524.8 mu m to approximately 81.3 mu m, and significantly decreases the lamellar transition structure region (alpha+gamma). During solution treatment, dispersed needle-like NbNi3 phases were observed in the Cu-15Ni-8Sn-0.2Nb alloy. After aging, the DP growth rate in the Cu-15Ni-8Sn-0.2Nb alloy was notably slower than those of the other alloys. This was attributed to NbNi3 phases at the grain boundaries hindering DP nucleation, with intragranular NbNi3 phases inhibiting DP growth . The phase transformation order of the solid solution Cu-15Ni-8Sn-0.2Nb at 673 K aging is: spinodal structure -* D022 ordered phase -* γ′ ordered phase -* DP. The hardness and tensile strength of the Cu-15Ni-8Sn-0.2Nb alloy peaked at 338.3 HV and 725.42 MPa, respectively, after aging for 120 min. Using the Johnson-Mehl-Avrami-Kolmogorov (JMAK) and Arrhenius equations, the activation energies of DP in Cu-15Ni-8SnxNb (x = 0, 0.2, 0.6 wt%) alloys were calculated to be 93.19, 148.64, and 98.33 kJ/mol, respectively. These values suggest that the diffusion of DP atoms in the Nb-containing alloys is hindered, which effectively inhibits DP formation.
10.1016-j.jmrt.2024.09.035	-1		In this paper, the Cu-10.8Al-8.3Mn-0.37Si alloy containing Mn5Si3 phase was obtained by adding Si element to the Cu-10.8Al-8.3Mn alloy. The two alloys were printed by laser powder bed fusion. The changes in the organization and tensile properties of the alloys and the mechanism were investigated. After Si addition, the Mn5Si3 nano phase precipitated in the alloy in addition to the beta(1) austenite phase. The Mn5Si3 phase was co-lattice with the beta(1) phase with an average size of 10 nm and was diffusely distributed. Standard tensile experiments showed that the yield strength of the Cu-10.8Al-8.3Mn-0.37Si alloy decreased by 57.7% and the elongation increased by 266% compared to the Cu-10.8Al-8.3Mn alloy, while the tensile strength remained essentially unchanged. The presence of Mn5Si3 phase provided nucleation points for martensite and promoted the generation of stress-induced martensite. Hence the yield strength was reduced. TEM results showed that the beta(1) phase in the Cu-10.8Al-8.3Mn-0.37Si alloy was fully transformed into stress-induced martensite after deformation, which displayed the transformation induced plasticity effect and hindered the slip of dislocations. Meanwhile, the Mn5Si3 phase was sheared by the stacking faults, which promoted the accumulation of hetero-deformation-induced stress. Therefore, the hardening capacity and plasticity of the Cu-10.8Al-8.3Mn-0.37Si alloy were enhanced. This work provides a new idea for the plasticity enhancement of Cu-Al-Mn-based shape memory alloys achieved by co-lattice nano-precipitated phase strengthening.
10.1016-j.jmrt.2024.09.066	14	strength; properties; conductivity; electrical; mechanical; cu-; grain; mpa; electrical conductivity; aging; precipitation; phase; mechanical properties; tensile; phases	Copper-based alloys have garnered significant attention for their potential in antimicrobial applications aimed at mitigating medical-related infections. Nonetheless, the alloying elements in conventional copper alloys frequently exhibit biotoxicity. This study explored the corrosion behavior, antimicrobial activity, and ion release of Cu-Fe alloys with varying iron contents and aging treatment. The results indicate that increasing the iron content in Cu-Fe alloys and applying appropriate aging treatment can enhance both the antibacterial efficiency and corrosion rate. Transmission electron microscopy (TEM) observations revealed a corrosion mechanism in which dispersed iron phases act as nucleation sites. These nanoscale precipitates increase the Cu/Fe interfacial area, thereby promoting ion release at the interface. Furthermore, in-situ scanning electron microscopy (SEM) revealed that corrosion products are more likely to detach in iron-rich segregated areas, which effectively promotes the sustained release of copper ions.
10.1016-j.jmrt.2024.09.071	-1		The copper (Cu)-beryllium (Be) alloy is a critical material for high-performance photomultiplier cathodes. The microstructure evolution of the beta phase in the Cu-2.8Be alloy subjected to cooling rate ranging from 0.5 to 80 C-degrees/ s after heat treatment. The non-isothermal phase transformation kinetics equation of the alloy was derived. At a cooling rate of 0.5 C-degrees/s, the beta phase completely transformed into the alpha phase and gamma phase through a eutectoid reaction (beta -> alpha + gamma). The gamma phase preferentially precipitates at locations with higher free energy, such as grain boundaries and defects in the parent phase. The orientation relationship between the alpha phase and the gamma phase follows the Kurdjumov-Sachs (K-S) relationship ([110](alpha) [111](gamma); (111)(alpha) (011)(gamma)), and the alpha phase nucleates and grows with a twin relationship to the Cu matrix. As the cooling rate increases, the transformation fraction of the beta phase decreases. The critical cooling rate at which the beta phase eutectoid reaction is completely suppressed is 80( degrees)C/s. A non-isothermal phase transformation kinetics equation for the beta phase eutectoid transformation was {established: f(r) = 1-exp-{34.703r(- 1.062)[exp(- 0.9107r)-0.3575]}(2.2)}, elucidating the relationship between the phase transformation fraction and the cooling rate, which provides a theoretical basis for controlling the microstructure of Cu-Be alloy through heat treatment. Validated by the Cu-3.3Be alloy, this equation demonstrates excellent universality.
10.1016-j.jmrt.2024.09.073	-1		As a typical age-strengthened alloy, Cu-Cr-Zr alloys have high strength, good electrical conductivity, and excellent wear resistance. In this work, the Cu-Cr-Zr-Nb alloys were in different aging states after the aging process. After aging at 460 degrees C for 4 h, the alloy was peak-aging. The common effect of the existence of the FCC Cr particle, which was coherent with the Cu matrix, and the increase in hardness improved the wear property of the alloy. The results of the wear test showed that the optimal wear parameter was a speed of 300 rpm and a load of 5 N. Under these wear parameters, the alloy had the lowest mean coefficient of friction (COF) value and the least mass loss, having the best wear resistance. Furthermore, the wear mechanism of the alloy was mainly adhesive wear and abrasive wear.
10.1016-j.jmrt.2024.09.222	-1		Inspired by the structure of nacre, bionic laminar composites composed of 85.6 wt% Cu, 11.9 wt% Al, and 2.5 wt% Mn were prepared using highly flexible Cu-coated graphene films as fillers. The effects of surface modification and graphene films content on the properties were investigated. Results indicated that the loss factor of composites with 0.1 wt% Cu-coated graphene films is improved by approximately 28% and reaches 0.044 compared to uncoated samples. The density and tensile strength are increased by up to 98% and 362 MPa, respectively. This enhancement is attributed to the improved bonding at the graphene films/matrix interface due to the Cu coating, which allows for efficient load transfer. Concurrently, the activation of interlayer sliding in the graphene films dissipates substantial energy. However, an excessive addition of graphene films leads to decreased density and increased internal defects in the composites, resulting in deteriorated properties. This study provides a reference for the preparation of CuAlMn matrix composites with enhanced mechanical and damping properties.
10.1016-j.jmrt.2024.10.007	-1		The stress relaxation resistance of a Cu-Ni-Si alloy strip after 48 h of initial loading stress of 80% sigma 0.2 at 125 degrees C was studied. The stress relaxation curve was fitted using a model. By employing EBSD, TEM, and other techniques, this study examined the microstructural characteristics of the Cu-Ni-Si alloy strip before and after stress relaxation. This study investigated the stress relaxation mechanism of the alloy and revealed that the stress relaxation rate of the Cu-Ni-Si alloy strip was 10.82% after 48 h at 125 degrees C. The stress relaxation process of the alloy strip was divided into two main stages. During the first stage, there was a significant rearrangement and movement of dislocations within the alloy strip, leading to a rapid decline in the remaining stress. In the second stage, the interaction among the Ni2Si phase, twins and dislocations led to a slow decrease in the remaining stress. After the stress relaxation of the alloy strip, the precipitated phase in the microstructure grew from 67 nm to 200 nm, the recrystallization microstructure increased from 57.91% to 62.42%, and the twin boundary content decreased from 22.1% to 18.5%. These observed changes in the microstructure are anticipated to further reduce the stress relaxation resistance of the alloy strip.
10.1016-j.jmrt.2024.10.033	-1		In this paper, the effects of Hf addition on the mechanical properties, electrical conductivity and microstructure of Cu-Sn-P alloy were investigated. The results show that the Hf addition can enhance the mechanical properties and electrical conductivity of Cu-Sn-P alloy. The alloy with 0.05 wt% Hf exhibits the best comprehensive performance with yield strength of 625 MPa, tensile strength of 661 MPa and electrical conductivity of 16.8 %IACS. Compared with the Cu-Sn-P alloy without Hf addition, the yield strength and tensile strength are increased by 8.4% and 7.8%, and the electrical conductivity is increased by 24.4%. The increase in the strength of Hf-added alloy can be attributed to the synergistic effect of multiple strengthening mechanisms, including fine grain strengthening, twin strengthening, dislocation strengthening, precipitation strengthening and Sigma 3n (n = 1, 2, 3) grain boundary strengthening. Moreover, the Hf-P precipitates can be observed in the Hf-added alloy. According to the amount of Hf addition, these precipitates can manifest as the fine HfP2 phase and the coarse HfP phase. The formation of Hf-P precipitates contributes to the precipitation strengthening and the purification of Cu matrix, thus contributing to the improvement of strength and conductivity.
10.1016-j.jmrt.2024.10.035	14	strength; properties; conductivity; electrical; mechanical; cu-; grain; mpa; electrical conductivity; aging; precipitation; phase; mechanical properties; tensile; phases	Under the condition of controlling the total rolling deformation to 80.0%, the effects of multi-pass rolling, the ratio of deformation between the first and second stages in two-stage rolling, and aging parameters on the microstructural evolution and property enhancement of Cu-Ni-Si alloy were investigated. The results showed that the second-stage rolling promotes the formation of high-density dislocations, significantly enhancing dislocation strengthening. Simultaneously, the high-density dislocations facilitate the precipitation of the second phase during aging, and concurrently improving the strength and electrical conductivity of the alloy. In the twostage rolling and aging process, a ratio of first-stage to second-stage rolling deformation less than 1 yields superior comprehensive properties. Specifically, when the first-stage rolling deformation is 35.0% and the secondstage deformation is 68.8%, the alloy achieves an optimal electrical conductivity of 49.53% IACS, hardness of 272.9 HV0.1, tensile strength of 773.0 MPa, and yield strength of 723.3 MPa. This is because a rolling ratio less than 1 results in higher dislocation density; the S-Ni2Si precipitates have a coherent relationship with the Cu matrix, the interparticle spacing of precipitates is smaller. The average grain size is refined from 1.29 mu m to 1.08 mu m, significantly enhancing grain boundary strengthening. Dislocation strengthening and second-phase strengthening are the primary strengthening mechanisms of the alloy, and the calculated alloy strength agrees well with the experimental values, with errors less than 3.4%. Additionally, the Avrami equation in phase transformation kinetics was utilized to study the variation law of the volume fraction of the S-Ni2Si phase with aging time.
10.1016-j.jmrt.2024.10.085	14	strength; properties; conductivity; electrical; mechanical; cu-; grain; mpa; electrical conductivity; aging; precipitation; phase; mechanical properties; tensile; phases	Pre-aging treatment was demonstrated to significantly enhance the mechanical properties of Cu-10Fe-1Nb (wt. %) composites. Specifically, after rolling and aging at 400 degrees C for 8 h, the microhardness, tensile strength, and elongation of the pre-aged samples reached 163 HV, 559 MPa, and 11.2%, respectively. The refinement of Ferich phases in pre-aged samples was primarily attributed to the increased shear strain between the Fe-rich phases and the matrix, which was driven by the precipitation-strengthening effect induced by pre-aging. Additionally, the matrix of the pre-aged samples suffered significant refinement as dynamic recovery and recrystallization of the matrix were suppressed during the rolling process, forming a high-density dislocation structure that greatly enhances the work-hardening effect. The main contribution to strength improvement in the Cu-10Fe-1Nb composites was identified as precipitation strengthening, refinement strengthening, and work hardening. Moreover, compared with the sample without pre-aging treatment, the refinement strengthening and work hardening effects of pre-aged samples exhibited substantial improvements, with increment of 49 MPa and 21 MPa, respectively.
10.1016-j.jmrt.2024.10.089	-1		In this paper, molecular dynamics simulation was used to investigate the micromechanical behavior of the Cu-Zr/Al composite interface after rapid solidification. The effects of different Zr contents and different strain rates on the tensile strength of the Cu-Zr/Al composite interface were investigated. The results show that the tensile strength of the composite plate increased and then decreased with the increase of Zr content, and the tensile strength is the highest when the Zr content is 0.33 wt%. It was found that the plastic deformation process of the composite model at different strain rates is similar, which is divided into three stages: the expansion of stacking faults in the Cu-Zr/Al solid solution, the expansion of stacking faults successively in the Al and Cu-Zr alloy layers, and the spreading of cross- stacking faults. But the greater the strain rate is, the slower the stacking faults fracture is. So the composite model with different strain rates had different fracture modes during the tensile fracture process. When the strain rate is 0.01 ps(-1) and 0.001 ps(-1) , it is a ductile fracture, while when the strain rate is 0.0001 ps(-1) , it is a brittle fracture.
10.1016-j.jmrt.2024.10.160	15	aging; strength; conductivity; electrical conductivity; electrical; mpa; treatment; strengthening; degrees; cu-; cold; precipitation; tensile strength; tensile; iacs	Cu-0.45Cr-0.1Zr-(0.3Ag) were produced and subjected to multistage thermo-mechanical treatment. The microstructure evolution and properties of the alloys during aging were investigated in detail and the effect of trace Ag on comprehensive properties of Cu-Cr-Zr alloy was discussed by kinetic and strength calculations. The results showed that Cu-0.45Cr-0.1Zr-0.3Ag alloy had a higher strength than Cu-0.45Cr-0.1Zr alloy while maintaining a high electrical conductivity. After multistage thermo-mechanical treatment, the tensile strength, yield strength and electrical conductivity of Cu-0.45Cr-0.1Zr-0.3Ag alloy reached 611 MPa, 601 MPa and 78.7 %IACS, respectively. The addition of Ag had little influence on the precipitation process of Cu-Cr-Zr alloy during aging: Cr particles transitioned from GP zones to face-centered cubic (fcc) structure and finally stabilized in body- centered cubic (bcc) structure, however, the composition of Zr precipitates changed after Ag doping. Most of Zr atoms segregated at grain boundaries in the form of Cu4AgZr in Cu-0.45Cr-0.1Zr-0.3Ag alloy instead of Cu5Zr in Cu-0.45Cr-0.1Zr alloy. The calculation results showed that the addition of Ag refined the size of Cr particle, increased the density of dislocations, enhanced the effect of dislocation strengthening.
10.1016-j.jmrt.2024.10.179	-1		Copper-silver alloy rod with high mechanical properties and stable conductivity are the key materials for the preparation of microfilaments used in endoscopy and other medical fields. In this paper, the microstructure of Cu-20Ag rod was regulated by adding trace rare earth Y in order to improve the comprehensive performance of copper-silver alloy further. and studies the distribution and existence of rare earth Y as well as the influence on the performance of copper-silver alloy rod billet. The results of research show that: rare earth Y mainly exists in the branching nodes of the eutectic organization, so that the alloy in the solidification of constitutional supercooling increases, thus refining the eutectic structure, and make it uniformly distributed. After addition of 0.01 wt%Y, Cu4Y was precipitated in the eutectic structure of the rod. After adding 0.03 wt%Y, the precipitates types increased to trace intermetallic compound AgY and nanoparticles Cu4Y. The increase of the interface between eutectic structure and Cu matrix decreases the electron scattering probability. This is the main factor to lead to the decrease of electrical conductivity. The precipitation hardening of precipitated phase and the increase of interface between eutectic structure and Cu matrix are the main factors for the increase of tensile strength of bar billet. The main factor of the decrease in the conductivity of rod billet is the increase of Ag phase dissolved in eutectic structure and the interface between eutectic structure and Cu matrix.
10.1016-j.jmrt.2024.10.180	8	hot; deformation; strain; strain rate; dynamic; hot deformation; recrystallization; dynamic recrystallization; flow; rate; flow stress; compression; constitutive; degrees; stress	In this study, the thermal deformation behavior of Cu-Ti-Zr(-Mg) alloys were investigated by Gleeble-1500D. The two alloys were deformed at 700-900 degrees C with 0.003-10 s(-1) strain rate. The intrinsic equations of the two alloys were constructed and calculated thermal activation energies, which indicates that it is improved from 325.67 kJ/mol to 344.03 kJ/mol after Mg addition. The result showed that the hot working area of Cu-Ti-Zr alloy is greatly extended after Mg addition, and rheological instability area is reduced. The morphology of the alloys was observed to analyze thermal behavior. It revealed that Mg elements inhibited the occurrence of dynamic recrystallization and shifted the texture types in the alloys by characterization of EBSD. TEM results showed that the phases during hot deformation in Cu-Ti-Zr-Mg are Cu4Ti and Cu(10)Zr7, which are in a semicoherent relationship with the Cu matrix.
10.1016-j.jmrt.2024.11.207	-1		This study explored the mechanical and tribological properties of Cu-1Cr-0.15Zr alloy processed through various routes. Aged + cryo-rolled sample (ACTR) exhibited the highest hardness and strength, solution treated + aged (STA) the highest ductility, and two-step cryo-rolled + aged (CTRACTRA) the highest deformation energy. TEM analysis revealed cellular dislocation structures and Zr-rich precipitates but no twins. Wear testing revealed that aging before cryo-rolling (ACTR) significantly improved tribological performance. The ACTR sample consistently showed the lowest wear rate and friction coefficient across all applied forces. Increasing sliding distance also impacted wear more than increasing load. SEM analysis indicated adhesive wear as the dominant mechanism. Oxidation was also observed at low forces and short distances for CTRACTRA and ACTR.
10.1016-j.jmrt.2024.11.213	-1		The steel/copper bimetallic structures inherit both the excellent thermal/electrical conductivity of copper alloys and the mechanical strength of steel, making it valuable for applications in heat exchangers, injection molds and the power industry. Laser powder bed fusion (LPBF) is a promising manufacturing method for the fabrication of steel/copper bimetallic structures, but the inhomogeneous heterogeneous interfaces still need to be subsequently processed to further enhance their mechanical properties. In this investigation, an attempt was made to optimize the interfacial microstructure of steel/copper bimetallic structures fabricated by the LPBF process through annealing treatment to improve their interfacial strength . As a result, the annealing treatment increased the interfacial bonding strength of the steel/copper bimetallic structure by 28% and without reducing the elongation. This is attributed to the elemental homogenization and internal stress release during heat treatment, as well as the mechanically interlocked structure of fine crystals embedded in coarse crystals formed by Cu/Fe interdiffusion at the boundary of the steel/fusion zone. However, no significant phase transitions were identified in the heterogeneous interface. A suitable heat treatment process can diffusely distribute the Cu/Fe immiscible phase and maintain fine grains. This work discusses in detail the microstructure evolution under different annealing treatments as well as the underlying mechanisms for the improvement of mechanical properties, providing a simple and effective method for post-treatment reinforcing the heterogeneous interface of 316L/CuSn10 bimetallic structure fabricated by LPBF.
10.1016-j.jmrt.2024.11.246	15	aging; strength; conductivity; electrical conductivity; electrical; mpa; treatment; strengthening; degrees; cu-; cold; precipitation; tensile strength; tensile; iacs	Cu-12Fe-0.42Si-0.008B alloy was formed by twin-roll strip casting. Studied the strengthening mechanism after adding Si and B elements and the effect of single/double stage cold rolling aging on its microstructure and properties. The solidification structure of the two alloys was dominated by equiaxed grains, with a sandwich structure formed by the Cu and the central Fe-rich phases. The tensile strength of the alloy increases with the increase of aging time. The maximum strength at 16 h of two-stage cold rolling and aging (450 degrees C) is 682.2 MPa, 52% higher than that of the Cu-12Fe alloy, and the saturation magnetic field strength increased by 29.4 %. This is attributed to the addition of Si and B elements to increase the number of primary iron-rich phases in the alloy and promote the precipitation of nano-alpha-Fe phase during aging. The finer nano-Fe-rich phase particles are generated with a coherent relationship between the precipitated Fe phase and the Cu bas, that is (1-1-1)Cu//(101)Fe. The strength of the alloy after two-stage cold rolling aging is always better than that of single-stage cold rolling. This is because the two-stage cold rolling treatment reduces the content of fibrous alpha-Fe phase in the alloy and increases the nanoscale spherical alpha-Fe phase. Confirming that the spherical alpha-Fe phase has a better strengthening effect. The relative conductivity of alloy increases with the increased aging time, with the highest relative conductivity of 53.9% IACS and 54.9% IACS obtained after 16 h of two-stage cold rolling aging.
10.1016-j.jmrt.2024.12.115	6	grain; deformation; strain; strength; dislocation; cu-; tensile; size; ecap; grain size; sfe; ductility; hardening; high; stress	For most metallic materials, the surface mechanical attrition treatment (SMAT) resulted in a substantial increase in the yield strength, but accompanied by a certain decrease in the ductility. However, the regulating of the yield strength and ductility in the gradient-structured Cu-Al-Zn alloys by the SMAT and annealing was less studied systematically. In this study, the microstructural evolution and mechanical properties of gradient-structured Cu-Al-Zn alloys with different stacking fault energy (SFE) after annealing were systematically investigated. The tensile properties show that the SMAT Cu-Al-Zn alloys with low SFE after annealing at 320 degrees C for 20 min exhibits a superior combination of strength and ductility. The microstructure characterizes reveal that the density of dislocations is decreased in the SMAT Cu-Al-Zn alloys with low SFE after annealing, meanwhile the degree of accumulated dislocations on the deformed twins is also weakened and maintains deformation twins feature, which thus achieve a superior balance of yield strength and ductility. Further analysis demonstrates that the annealed SMAT Cu-Al-Zn alloy with low SFE still maintains an obvious HDI strengthening. Furthermore, the digital image correlation (DIC) results indicate that during tensile deformation, gradient-structured Cu-Al-Zn alloys with low SFE can form dispersed strain bands, which contributes to improved ductility. This study provides a feasible strategy for regulating the strength and ductility of gradient-structured copper alloys.
10.1016-j.jmrt.2024.12.212	-1		In this work, mechanical alloying combined with spark plasma sintering (SPS) processes were used to prepare Cu-0.65Cr-0.5Y-0.15Cu(2)O, Cu-0.65Cr-0.5Y-0.5Al-0.15Cu(2)O and Cu-0.65Cr-0.5Y-0.5Si-0.15Cu(2)O (wt%). The effects of the introduction of Al or Si on the microstructure, mechanical properties, thermal conductivity and thermal stability of ODS Cu alloy were studied. All three alloys exhibit heterogeneous mixed grain structures, including coarse and fine grains, with oxide nanoparticles uniformly distributed throughout the copper matrix. However, the addition of Al or Si leads to grain refinement and further refinement of the oxide nanoparticles. Compared with ODS Cu alloy, the ultimate tensile strength of ODS Cu-Cr-Si alloy increased from 554 MPa to 621 MPa, the elongation at break increased from 8.8% to 11%, and the thermal conductivity increased from 221.5 W m(-1) K-1 to 262.3 W m(-1) K-1, respectively. The ODS Cu-Cr-Si alloy also shows ultrahigh microstructural stability upon annealing at 600 degrees C for 50 h . The excellent strength, ductility and thermal conductivity comes mainly from the high-density coherent nano-Y2Si2O7 (<15 nm) dispersed in ultrafine grain Cu matrix. In addition, it is found that the microalloying Si and Al significantly improve the MA efficiency. These findings indicate that an ODS Cu alloy promising for application under high-temperature (HT) conditions can be produced effectively and efficiently by combining composition design and process optimization.
10.1016-j.jmrt.2024.12.232	-1		To select suitable reinforcement and lubricant for Cu matrix and thus improve the tribological performance, the stability of widely used reinforcements and lubricants, such as CrB2, TiB2, graphite (C) and MoS2, in the copper matrix during sintering process was studied. The content of each reinforcement or lubricant was fixed at 10 wt%, and the powder mixture was sintered by a fast hot-pressed sintering machine at 950 degrees C under 40 MPa for 1 h under a vacuum atmosphere (<10 Pa). Then, microstructure and phase composition of the composites resulted from 10%CrB2-Cu, 10%TiB2-Cu, 10%MoS2-Cu, 10%C-Cu, 10%CrB2-10%C-Cu, 10%TiB2-10%C-Cu, 10%CrB2-10%MoS2-Cu and 10%TiB2-10%MoS2-Cu powder systems were investigated systematically, Subsequently, the potential decomposition and reaction behavior was discussed based thermodynamic analysis. Results show that single CrB2, TiB2 or C phase can exist stably in copper matrix, but MoS2 is prone to react with Cu to form Cu2S and Mo2S3. Both CrB2 and TiB2 can co-exist with C in the Cu matrix, but react with MoS2 to form Cu2S, Mo2S3 as well as ternary CuCrS2 and CuTi2S4 phase, since the negative Gibbs free energy change of the corresponding reaction equations. Finally, the strengthening effect of CrB2 and TiB2 along with the lubricating effect of graphite (C) are promise to work in Cu matrix from the viewpoint of crystal structure integrity.
10.1016-j.jmrt.2024.12.270	-1		Cold spray, an additive manufacturing technique based on plastic deformation of particles, was employed to prepare Cu/Invar alloy composites to avoid issues from other preparation methods, like undesirable thermal expansion anisotropy from the extrusion method and the excessive inter-diffusion between Cu and the Invar alloy from the sintering method. For the target Cux(Fe64Ni36)100-x(x = 30-70, wt%) composites prepared by cold spray, the improved thermal expansion anisotropy was reflected by the negligible difference between the thermal expansion coefficient alpha along and perpendicular to the spray direction, and simultaneously no obvious inter- diffusion was observed between Cu and the Invar alloy Fe64Ni36 after annealing at 500 degrees C. Both alpha and the thermal conductivity A increased slightly due to the release of internal stress and recrystallization of Cu. alpha of the annealed composites basically agreed with the theoretical predication, but A was far below the values predicted by the Hasselman-Johnson model, mostly because the Invar alloy had an extraordinarily large surface area caused by impact deformation. Even so, the cold-sprayed Cu/Invar alloy composites had clearly advantageous comprehensive performance than those prepared by the traditional sintering and melting methods. Among Cu/ Invar alloy composites prepared by different methods, the annealed Cu50(Fe64Ni36)50 was the only composite having A larger than 100 W/m center dot K and isotropic alpha smaller than 10 x 10-6/oC. In addition, the cold-sprayed Cu/ Invar alloy composites had a good plasticity (after annealing) that is rarely seen in traditional Cu-based composites with high thermal conductivity, presenting a good application potential for electronic packaging materials.
10.1016-j.jmrt.2025.01.007	-1		To investigate methods for enhancing the resistance of electrical contact materials to arc erosion, this study focuses on the preparation and properties of novel composites. Al2O3-Cu/30Cr and 0.3GO-0.3Ag/Al2O3-Cu/ 30Cr composites were fabricated using vacuum hot press sintering. The composites achieved high relative densities (99.82% and 99.6%), good electrical conductivities (47.8% IACS and 46.1% IACS), excellent hardness (142 HV and 158 HV), and superior thermal conductivities (124 W/(m & sdot;K) and 188 W/(m & sdot;K) at 150 degrees C), with compressive strengths of 693 MPa and 711 MPa. In addition, the addition of GO-Ag improved the resistance of the material to arc erosion, and the transfer and loss of the material were significantly reduced. Under the 30 V DC 30 A condition, the anode mass gain, cathode mass reduction and total mass loss decreasing from 3 mg, 3.73 mg, and 0.73 mg-1.97 mg, 2.30 mg, and 0.33 mg, respectively. Furthermore, the transmission electron microscopy (TEM) and energy dispersive spectrometer (EDS) results show that Cr3C2 compounds effectively pin the Cr-Cu interface. High thermal conductivity and good micro-interface improve the electrical contact properties of the composites and help to improve the compression properties.
10.1016-j.jmrt.2025.01.042	-1		The preferential oxidation of alloying elements has long been recognized as the primary mechanism underlying the oxidation resistance of copper alloys. However, the presence of various alloy phases within the Cu matrix complicates the oxidation behavior. Herein, combined DFT calculations and antioxidation experiment were conducted to evaluate the oxidation behavior and underlying mechanism of Cu-La alloys. The results indicate that the oxidation resistance of Cu is significantly enhanced by La element with a reduced mass gain of 49% at 100 degrees C for 100 h . The effects of oxidation behavior of Cu6La on the oxidation resistance of Cu is further explored by DFT calculations. It reveals that the Cu6La phase with a low work function exhibits a strong affinity for the O atoms. However, the diffusion activation energy of the absorbed O is calculated to be lower in Cu6La than that of O in Cu, which is conducive to mitigate the further erosion of O on Cu matrix. Moreover, the Cu2O-La layer formed on the Cu6La surface is more stable and the oxygen diffusion coefficient in it is lower, which impedes the entry of oxygen. This work advances the understanding of alloying effect on oxidation of Cu surfaces that can be extended to other metal surfaces.
10.1016-j.jmrt.2025.01.067	-1		In this study, submicron tungsten carbide (WC)-reinforced Cu matrix composites (WC/Cu) were fabricated using an extensible manufacturing process (flake powder metallurgy of WC/Cu master alloy, casting and cold rolling of WC/Cu ingots). X-ray diffraction (XRD), energy dispersive spectroscopy (EDS) and electron backscatter diffraction (EBSD) techniques were jointly employed to characterize phases and microstructures of the as-cast and rolled WC/Cu composites. The friction and wear behavior of these composites was investigated at different temperatures (25, 100, and 300 degrees C). The results indicate that a significant amount of submicron WC particles was successfully incorporated into the Cu matrix. As cold rolling deformation increases, the pseudo- dispersion of WC particles diminishes, resulting in a more uniform particle distribution. A comparison of wear volume losses under various conditions shows a significant improvement in the wear resistance of the WC/Cu composite compared to pure Cu. Notably, the NC1 (with a 20% rolling reduction) and NC2 (with an 80% rolling reduction) samples exhibit outstanding wear resistance at 300 degrees C, with lower wear volume loss than at 25 and 100 degrees C. Such improvement is attributed to the reinforcement of the oxide film at 300 degrees C by the addition of submicron WC particles.
10.1016-j.jmrt.2025.01.077	-1		Cu-Al alloys are widely utilized in the electrical, aerospace, and automotive industries. In this study, Cu-Al alloys with varying Al contents (ranging from 6, 8, 10, 12, and 14 wt%) were fabricated by directed energy deposition (DED) using two types of powders: CuNi2SiCr and Al-Mg-0.7Si. The deposition sample with 14 wt% Al fractured due to the high gamma 2 phase content while the others exhibited good quality, without cracks or significant defects. The 6 wt% Al exhibited a typical DED melt pool microstructure, which is composed of a single alpha phase. As the Al mass fraction increased, the microstructure became finer, and disordered (beta ') and ordered (beta 1) needle-like martensite appeared in 8, 10, and 12 wt% Al samples. Furthermore, a beta ->(alpha+gamma 2) eutectoid transformation occurred at high Al content, resulting in the appearance of plum blossom-shaped gamma 2 phase in 10 and 12 wt% Al samples. The properties and oxide film formation on each sample were investigated using electrochemical measurements. The corrosion resistance of the samples increased with increasing Al content. Moreover, the 12 wt% Al sample exhibited the smallest corrosion rate, with corrosion resistance comparable to cast NAB, which is attributed to the protection of the dense Al2O3 oxide film that formed on its surface. Furthermore, the formation mechanism of the oxide film and the corrosion behavior of the microstructure of each specimen were discussed in detail through long-term immersion corrosion tests. This study provides effective strategies and new ideas for constructing Cu-Al alloys with excellent corrosion resistance.
10.1016-j.jmrt.2025.01.165	-1		Cu/Kovar composite sheet were prepared through hot pressing followed by hot rolling, and their microstructure and thermal conductivity were investigated. With increasing rolling reductions, the Kovar particles as well as the grains of Cu and Kovar exhibit continuous elongation in the rolling direction due to coordinated deformation. The thermal conductivity in the normal direction of the composite decreases with increasing rolling reduction, which is influenced by factors such as composite density, grain size, dislocation density, and Kovar particle morphology. In the composite subjected to 70% reduction, {011}<100> and {011}<111> emerge as the predominant textures in the Cu phase. Although similar thermal conductivity is observed in the transverse and rolling direction of the composites, it is lower than that in the normal direction. The anisotropy of the composites results from both the texture formation and morphologies evolution in the Kovar particles after hot rolling.
10.1016-j.jmrt.2025.01.242	-1		Aging precipitation is an important process that affects the mechanical and electrical properties of Cu alloys. Quantitative prediction of microstructure evolution during aging process is crucial for controlling their performance. The mean field method is an important means of precipitation simulation, but its reliability strongly depends on the input of accurate thermodynamic and kinetic data. In this paper, a comprehensive study on the thermodynamic, diffusion, and precipitation behavior of Cu-Ni-Si-Co alloy was conducted by combining modeling and experimental techniques. Firstly, a thermodynamic database of quaternary Cu-Ni-Si-Co system was constructed and verified by key experiments. Then, HitDIC software was used to establish an atomic mobility database by incorporating experimental quaternary diffusion properties, allowing for accurate determination of interdiffusion coefficients. After that, a quantitative precipitation simulation framework was developed and applied to Cu-Ni-Si-Co alloys. The simulated volume fractions of (Ni,Co)2Si precipitates in different quaternary alloys along with the time agree well with the experimental data. It is anticipated that the presently obtained quantitative composition-process-microstructure relation can be directly used for efficient design of Cu-Ni-Si-Co alloys, and the developed approaches for establishing thermodynamic/kinetic database as well as quantitative precipitation simulation framework is generally applicable to other multicomponent alloys.
10.1016-j.jmrt.2025.02.085	14	strength; properties; conductivity; electrical; mechanical; cu-; grain; mpa; electrical conductivity; aging; precipitation; phase; mechanical properties; tensile; phases	A Cu-4Ti-0.5Cr-0.5 Mg alloy, specifically designed to achieve superior strength and conductivity, was subjected to pre-aging, cold rolling, and final aging to improve its mechanical and electrical characteristics. Comprehensive evaluations of the microstructure and performance of the alloy were conducted using advanced techniques, such as TEM analysis, tensile testing, hardness measurements, and assessments of electrical conductivity (EC). The addition of Cr and Mg to Cu-Ti alloys led to the formation of Cr2Ti intermetallic compounds and suppressed the formation of the (3-Cu4Ti phase. After pre-aging, cold rolling, and the final aging treatment, the final alloy exhibited notable improvements, with a hardness of 362 HV, yield strength of 1080 MPa, tensile strength of 1200 MPa, and EC of 10.78%IACS, which are superior to those of direct cold rolling. The calculated contributions from diverse strengthening mechanisms harmonized effectively with the tensile results, underscoring the pivotal role of precipitation hardening facilitated by nanoscale alpha-Cu4Ti particles in Cu-Ti alloys.
10.1016-j.jmrt.2025.02.092	14	strength; properties; conductivity; electrical; mechanical; cu-; grain; mpa; electrical conductivity; aging; precipitation; phase; mechanical properties; tensile; phases	This study investigates the effect of Sc doping on the deformation microstructure and rolling texture of Cu-Cr-Zr-Sc alloys. After solution treatment + 80% rolling + 450 degrees C x 1 h aging treatment, the ultimate tensile strength, yield strength, hardness, and electrical conductivity of the Sc doping alloy reached 573.5 +/- 1.52 MPa, 536.52 +/- 18.47 MPa, 203.91 +/- 5.08 HV, and 66.76 +/- 0.16% IACS, respectively. Compared with the non-doped alloy, the mechanical properties are enhanced while the electrical conductivity remains at a relatively high level. The deformation microstructure of the Sc doping alloy exhibited shear bands and the fine grains within the shear bands had minimal impact on the plasticity compared to the external heterogeneous structure. Additionally, the presence of the {325}<10 15 12> orientation indicates that Sc promotes the transformation of the Copper texture, reducing its intensity and facilitating the formation of Brass-type shear bands. The {110}<151> orientation generated during the rolling process may be related to the volume effect caused by the increase in the fraction of deformation twins after Sc doping. Based on the precipitation kinetics results, it is proposed that the doping Sc may promote the formation of solute atom clusters, thereby altering the stress state of the material. Simultaneously, the reduction in stacking fault energy inhibits cross-slip, and the combined effects of these factors lead to the formation of shear bands. Compared with the alloy without Sc, the high strain within the shear bands somewhat promotes static recrystallization behavior during aging treatment.
10.1016-j.jmrt.2025.02.116	14	strength; properties; conductivity; electrical; mechanical; cu-; grain; mpa; electrical conductivity; aging; precipitation; phase; mechanical properties; tensile; phases	Highly conductive single-crystal copper processing wire is a critical material in the fields of audio-video, new energy, and other conductor transmission applications. Enhancing its electrical conductivity has emerged as a research hotspot. In this study, single-crystal copper processing wires with varying diameters were produced through continuous deformation of Y micro-alloyed single-crystal copper rod billets. XRD, EBSD, and TEM were employed to characterize and analyze the materials. The influence of Y on the impurity elements and microstructural features of single-crystal copper processing wire under high-strain deformation was investigated, revealing the mechanism behind the changes in electrical conductivity. The results demonstrate that the electrical conductivity of Cu-0.03Y, with a diameter of 0.18 mm, reached 98.01% IACS, representing a 1.15% improvement over that of single-crystal copper processing wire. This enhancement is attributed to the presence of nanoscale precipitates (YP, Y2S3), which reduce electron scattering caused by solute atoms. In the undeformed stage, rare earth microalloying reduces the grain size and electrical conductivity of single-crystal copper processing wire, increases the deformation dislocation accumulation capacity, and promotes recrystallization and twinning. When the deformation reaches Phi 0.18 mm, the grain size of the single-crystal copper processing wire exhibits a multiscale microband structure. Nanoscale microbands (<200 nm) possess lower dislocation densities and serve as effective channels for electron mobility. Consequently, the enhancement in electrical conductivity can be attributed to the reduced electron scattering effect facilitated by the precipitated phases, nanoscale microbands, and twins, which promote free electron movement.
10.1016-j.jmrt.2025.02.131	14	strength; properties; conductivity; electrical; mechanical; cu-; grain; mpa; electrical conductivity; aging; precipitation; phase; mechanical properties; tensile; phases	High-strength, high-conductivity (HSHC) materials find broad application in environments demanding both high stress tolerance and efficient power transmission, where a precise balance between strength and conductivity is critical. In this study, refractory high-entropy alloy (RHEA) with excellent strength and thermal stabilityequiatomic TiZrNbTa is developed as novel reinforcement materials in Cu matrix. The nanocrystalline TiZrNbTa phase, synthesized through mechanical alloying, provides superior reinforcing effect in the Cu matrix compared to coarse-crystalline TiZrNbTa phase. Controlled elemental diffusion between the two phases, achieved by adjusting the sintering temperature, further optimizes the interfacial bonding, resulting in Cu-20 wt% TiZrNbTa composites with ultra-high strength (1081 +/- 33 MPa) and excellent conductivity (41.5 +/- 2.5% IACS). The finding broadens the application potential of nanocrystalline RHEA as stiffening phases, promoting their integration into the design of HSHC alloys.
10.1016-j.jmrt.2025.02.241	-1		High entropy alloys are a new generation of materials that have attracted the interest of many scientists due to their unusual properties. Corrosion destroys more than 3% of the world's gross domestic product. In contrast to classical alloy design philosophy, high entropy alloys (HEAs) have unique microstructures in which several elements are randomly arranged solid solutions. This article presents two alloy systems (CuCrFeMnNi with 5 wt% Cu and CuCrFeMnNi with 10 wt% Cu) that contain readily available and inexpensive raw materials and have the potential to form solid solution structures. A modeling program (MatCalc) was used to simulate phase formation by CALPHAD and non-equilibrium solidification. The selected alloys were fabricated in an induction furnace. Physical-chemical and microstructural characterization was performed on selected compositions. The crystal structure of the alloy was determined by X-ray diffraction method. The modelling and experimental results showed a solid solution-based structure in the cast samples. The structures for 5 wt% and 10 wt% alloys showed similar phase configuration. The alloy with higher Cu percentage generated higher microhardness but lower corrosion resistance in the as-cast state.
10.1016-j.jmrt.2025.03.114	-1		Since the glass structure is inherited from the alloy melt, the thermal history experienced by the melt during cooling significantly influences the structure and properties of metallic glasses. In this work, the effect of melt quenching temperature on the atomic structure, thermophysical properties, and mechanical properties of a Cu-Zr-Al metallic glass is systematically investigated, using a combination of state-of-the-art techniques, including synchrotron-based high-energy X-ray diffraction and chip-based flash differential scanning calorimetry. It is found that for the studied Cu-Zr-Al alloy, the temperature window for preparing completely amorphous and contamination-free ribbons is remarkably narrow, spanning merely similar to 150 K. This window is bounded by heterogeneous nucleation due to the unmelted nuclei at the lower limit and significantly increased O content due to severe chemical reactions at the higher limit. Furthermore, the glass transition, crystallization, thermal stability, and mechanical properties of the Cu-Zr-Al alloy are found to be highly sensitive to the melt temperature prior to quenching during melt-spinning. Two key factors-the disordering and homogenization effects-as well as the progressive enhancement of O contamination with increasing quenching temperature-are revealed to govern the structural and property evolutions. These findings provide valuable insights into tailoring glass structures and properties through the deliberate control of melt thermal history.
10.1016-j.jmrt.2025.03.119	-1		To overcome the challenge of using data-driven methods for alloy design in extremely limited sample data, this study proposes a rapid alloy design strategy that integrates orthogonal experiments, machine learning, and Pareto analysis. The Cu-0.22Cr-0.23Sn-0.25Zn-0.025Si alloys (C2ZS2) developed in our previous research work is used as a research case for process optimization. A small dataset through 25 groups of orthogonal experiments was established and the support vector machine regression algorithm was used to construct a machine learning model for the relationship of aging parameters and properties. Furthermore, improved Pareto analysis was used to optimize aging parameters and accelerate alloy design efficiency. C2ZS2 alloys exhibited excellent comprehensive properties after optimized aging parameters (primary aging at 490 degrees C for 9 h and secondary aging at 420 degrees C for 4 h), achieving the combination of high strength and high electrical conductivity, with a tensile strength of (600 +/- 2) MPa and an electrical conductivity of (75.1 +/- 0.4) %IACS. Remarkably, it reached the dual upper limits of mechanical and electrical properties of comparable commercial EFTEC-64T-C alloys for high-end lead frame manufacturing, with tensile strength of 490-588 MPa and conductivity of 71 %IACS-75 %IACS.
10.1016-j.jmrt.2025.03.215	14	strength; properties; conductivity; electrical; mechanical; cu-; grain; mpa; electrical conductivity; aging; precipitation; phase; mechanical properties; tensile; phases	In order to investigate the effect of Zr addition on Cu-Ni-Si alloys, this study developed four Cu-Ni-Si-(Zr) alloys with different Zr contents based on the Cu-3.2Ni-0.7Si alloy and systematically analyzed their microstructure and property variations. After undergoing the same deformation and heat treatment processes, it was found that, in addition to Ni2Si, the alloy also formed the intermetallic compound Ni16Zr6Si7. As the Zr content increased, the activation energy for Ni2Si precipitation gradually decreased, leading to an increased precipitation rate. Meanwhile, the particle size and content of Ni16Zr6Si7 also increased. During hot rolling, Ni16Zr6Si7 promotes the nucleation Cu grain recrystallization and pins the grain boundaries, leading to a gradual reduction in grain size. This reduction in grain size contributes to improved plasticity and toughness of the alloy. However, due to the relatively large particle size, the formation of Ni16Zr6Si7 has a smaller strengthening effect on the alloy. The increase in alloy strength primarily relies on the precipitation strengthening provided by the nano-sized Ni2Si formed during heat treatment. Therefore, when the Zr content is 0.05 wt%, the strengthening effect of Ni2Si is significantly improved compared to the Cu-3.2Ni-0.7Si alloy, while the precipitation of Ni16Zr6Si7 particles remains relatively low, resulting in the best overall performance of the alloy. After aging at 450 degrees C for 6h, the peak hardness of Cu-3.2Ni-0.7Si-0.05Zr reaches 270.1HV, with conductivity of 37 %IACS, tensile strength of 692.5 MPa, and elongation of 10.1 %.
10.1016-j.jmrt.2025.04.019	14	strength; properties; conductivity; electrical; mechanical; cu-; grain; mpa; electrical conductivity; aging; precipitation; phase; mechanical properties; tensile; phases	This study systematically analyzed the corrosion behavior of the Cu-3Fe-5Zn alloy at various annealing temperatures, focusing on the influencing factors and mechanisms of intragranular, intergranular, and Cu/Fe interfacial corrosion. Combing experimental data with the Lifshitz-Slyozov-Wagner (LSW) theory, the diffusion coefficients of Fe at 650 degrees C and 800 degrees C were found to 7.62 x 10-17 m2/s and 3.95 x 10-15 m2/s, respectively. The coarsening rate at 800 degrees C (1.06 x 10-26 m3/s) was significantly higher than at 650 degrees C (7.35 x 10-29 m3/s), indicating that higher annealing temperatures promote Fe precipitate coarsening and reduce the number of precipitates, thereby lowering the Cu/Fe interfacial corrosion rate. Additionally, the intergranular corrosion was closely related to grain boundary connectivity. As the annealing temperature increased, the proportion of coincidence site lattice (CSL) grain boundaries increased, reducing the grain boundary connectivity, which in turn decreased the corrosion and Cu ion release rates. In particular, when the annealing temperature exceeded 700 degrees C, the CSL boundaries effectively disrupted the grain boundary network, significantly inhibiting inter-granular corrosion. Finally, an increased annealing temperature decreased the dislocation density, thereby mitigating intragranular corrosion. The result of this study provides theoretical support for controlling the ion release rate of the Cu-3Fe-5Zn alloy.
10.1016-j.jmrt.2025.04.036	17	wear; composites; coating; friction; composite; coatings; surface; tribological; properties; wear resistance; resistance; powder; sliding; matrix; wear rate	The improvement in the properties of aluminum bronze alloys after nitriding is limited due to the immiscibility of nitrogen atoms with the copper matrix. To address this issue, a Cu-Al intermetallic compound prelayer is used, and the rare earth element Y is introduced to facilitate the diffusion of nitrogen atoms, thereby significantly enhancing the surface properties. The aluminum bronze alloy samples pre-cladded Al/AlY layers were obtained by low-temperature plasma nitriding, and the microstructure and properties of the composite modified layers were investigated. The results showed that a composite modified layer containing rich AlN -> rich Cu9Al4 -> rich Al6Cu6Y was formed on the surface of Cu-Al alloy. The layer was closely bonded to the substrate and had no obvious defects. Compared to pre-cladded with Al, the thickness of the modified layer increased. By comparing with the modified layer, the pre-cladded AlY and nitrided sample exhibited the best comprehensive properties. This mainly depended on the concentration and distribution of N element in the modified layer. The results of first principles calculation confirmed that the addition of rare earth element Y could significantly reduce the solubility energy of N atom and greatly promote the nitriding process. Therefore, the concentration of nitride in the composite modified layer was increased, the grain was refined, and the final comprehensive performance was improved.
10.1016-j.jmrt.2025.04.040	-1		W-Cu composites are widely used as electrode materials, electronic packaging materials, heat sinks, and targets in the defense industry, aerospace, and electronic information fields due to their good conductivity, high melting point, good mechanical properties, and good anti-arc erosion performance. In recent years, high-performance W alloys have gradually become the key materials in the defense industry and cutting-edge technologies, and new processing technologies have greatly improved the material density, uniformity of microstructure, mechanical properties, and physical properties of W alloys, but have also raised higher requirements for the high reliability, zero accidents, and long service life of defense and military materials. By optimizing the composite design and fabrication process, controlling the growth of microstructure and interfacial diffusion, and improving the fine grain distribution and uniformity, the densification, mechanical properties, and anti-arc erosion performance of W-Cu composites can be further improved. This paper reviews the evolution of preparation technology and modulation strategy for W-Cu composite, discusses the relationship between microstructure growth and mechanical properties of W-Cu composites, and systematically summarizes the influence mechanisms of alloy element content, existence form and microstructure on the electrical and thermal conductivity, strength, and erosion resistance of W-Cu composites. Finally, the future development trends and application prospects of W-Cu composites, including ultra-high voltage switchgear, hypersonic thermal protection systems and electromagnetic rail gun components, are prospected. The research results can provide reference for the material component design, advanced fabrication technology, microstructure and performance control of highperformance W-Cu composite materials in key fields and extreme service evaluation.
10.1016-j.jmrt.2025.04.054	1	shape; memory; shape memory; damping; martensite; martensitic; damping capacity; transformation; capacity; strain; superelasticity; temperature; cu-al-mn; shape memory effect; effect	To enhance the damping capacity at 350 K, the martensitic transformation temperatures must be increased. However, the increment in martensitic transformation temperatures can deteriorate the damping capacity. Whether good damping capacity can be obtained at elevated temperature is unknown to us. In this paper, we carefully investigated the evolution of damping capacity and vacancy behavior with the environmental temperature in ductile Cu-Al-Mn-Ni alloys with different Ms temperatures. Our results showed that the damping capacity in Cu-Al-Mn-Ni alloys subjected to 15 min step-quenching all showed an obvious degradation tendency with the increment in environmental temperature to above 313 K. The reduction of martensite amount and mobility of martensite boundaries could rationalize the degradation of damping capacity with the environmental temperature. The original number of vacancies on the martensite boundaries (Nvmb), which is positively dependent on the Ms temperature, controls the degradation rate of damping capacity in martensitic Cu-Al-Mn-Ni alloys. Among the experimental Cu-Al-Mn-Ni alloys, the Cu-18.0Al-8.4Mn-2.5Ni alloy with Ms = 360 K have the superior resistance to the degradation of damping capacity with the environmental temperature. In addition, we found that a critical temperature for vacancy diffusion exists at between 313 K and 333 K. With Ms temperature below the critical temperature, the alloy has a far lower original Nvmb than the one with Ms above the critical temperature. These findings highlight the importance of lowering the original Nvmb and increasing the critical temperature on improving the damping capacity at elevated temperatures.
10.1016-j.jmrt.2025.04.181	-1		The effect of different carbon sources (CS) and the underlying mechanisms on wetting behavior, interfacial reaction products, and spreading kinetics at the reactive wetting interface between Cu-based alloys and carbon materials during brazing and composites preparation remain unclear. This study investigates the reactive wetting behavior of a Cu-20Sn-2Cr alloy on various carbon substrates (graphite (Cgr), polycrystalline diamond (CPD), vitreous carbon (CV), and multi-walled carbon nanotubes Bucky paper (CMW)) at 1100 degrees C using a modified sessile drop method. The results indicate the equilibrium contact angle (Be) of Cgr(7 degrees), CPD(8 degrees), and CV(11 degrees) are close to each other, whereas the Be values of CMW-back (83 degrees) and CMW-front (69 degrees) are higher. The reaction product layer (RPL) in Cgr, CPD, and CV consists of a continuous and dense chromium carbides (CrmCn); the interface of CMW exhibit an alloy + nanoscale Cr3C2 cluster transition zone. The spreading kinetics of Cgr, CPD and CMW are controlled diffusion of Cr atoms to the triple line (TL) front, while Cv is controlled first by the diffusion of Cr atoms to the TL front, then is controlled by the reaction between Cr and C atoms at the TL front.
10.1016-j.jmrt.2025.04.208	14	strength; properties; conductivity; electrical; mechanical; cu-; grain; mpa; electrical conductivity; aging; precipitation; phase; mechanical properties; tensile; phases	Phosphorus, as a critical deoxidation and microalloying element, significantly influences the stacking fault energy (SFE) and tensile properties of oxygen-free copper. In this study, oxygen-free copper samples with varying phosphorus contents were prepared, and the impact of phosphorus content on SFE and its intrinsic relationship with tensile properties and microstructural evolution were systematically investigated using advanced microscopic characterization techniques, including EPMA, EBSD, and TEM. The results indicate that: (1) SFE decreases as phosphorus content increases; (2) Increasing phosphorus content markedly enhances the tensile properties of the samples. Specifically, the tensile strength and elongation of the P1400 sample are 194 MPa and 20.14 %, respectively, representing improvements of 30 MPa and 4.37 % over the P0 sample; (3) The reduction in SFE facilitates the formation of twins and stacking faults, with twin boundaries acting as barriers to dislocation slip. Additionally, the synergistic effects of phosphorus pinning and fine-grain strengthening impede dislocation movement during tensile deformation, thereby enhancing both strength and ductility.
10.1016-j.jmrt.2025.04.224	-1		Although graphite flakes (GF)/Cu composites have high thermal conductivity (TC) in the basal plane direction of GF, the problem of high coefficient of thermal expansion (CTE) makes it unable to meet the requirements of thermal management. Herein, a hybrid reinforcement strategy combining graphite flakes and carbon fibers (CF) was employed, and the (GF+CF)/(Cu+0.7 wt%Ti) composites were fabricated by spark plasma sintering and matrix alloying. Structural characterization revealed that the composites have a highly oriented structure and a nanoscale thickness TiC interlayer is formed at the interface. The effect of the relative content of reinforcements on the (GF+CF)/(Cu+Ti) composites' microstructure and in-plane thermal properties was systematically investigated. As the ratio of GF to CF changed from 60 vol%:0 vol% to 30 vol%:30 vol%, although the in-plane TC of the composites decreased from 658.2 W/mK to 495.1 W/mK, the in-plane CTE significantly reduced from 12.90 ppm/K to 6.62 ppm/K, thereby meeting the low CTE requirement of thermal management materials (CTE<10 ppm/K). Notably, the CTE significantly decreased by sacrificing a small amount of thermal conduction performance, resulting in excellent comprehensive thermal properties. Improvement of CTE was attributed to the polycrystalline orientation characteristics of the graphene layers in CF, which effectively constrained the thermal expansion of the copper matrix. The maintenance of high thermal conductivity is related to the consistently high orientation distributions of GF and CF and interface modification. According to the acoustic mismatch model, it can be found that the formation of a nanoscale thick TiC interlayer is beneficial for reducing interfacial thermal resistance and improving the TC of composites. In summary, the hybrid reinforcement strategy, highly oriented structure, and interface modification effectively solve the challenges faced by graphite flakes/Cu composites as thermal management materials.
10.1016-j.jmrt.2025.04.292	-1		In this study, CuxCoCrMoNi high-entropy alloys with different Cu contents (x = 0, 0.3,0.6,0.9) were prepared by vacuum arc melting, and their tribological behaviors under 5-15 N load were systematically studied. XRD analysis shows that all the alloys are single FCC phase. SEM-EDS analysis showed that Cu element segregated in the interdendritic region (IR) to form Cu-rich FCC2 phase. Vickers hardness test shows that the hardness of CuxCoCrMoNi HEAs with Cu is higher than that of CoCrMoNi alloy without Cu. Friction experiments show that the alloy's average friction coefficient decreased from 0.82 of CuxCoCrMoNi (x = 0) to 0.56 of (x = 0.3). The wear rate decreased from 4.1 x 10-4 mm3/(N center dot m) (x = 0) to 2.6 x 10-4 mm3/(N center dot m) (x = 0.3). Then the increase of Cu content increases the average friction coefficient from 0.53 (x = 0.3) to 0.62 (x = 0.9). However, due to the lubrication of the oxide layer, the wear rate gradually decreased from 1.98 x 10-4 mm3/(N center dot m) (x = 0.3) to 1.17 x 10- 4 mm3/(N center dot m) (x = 0.9). EDS analysis confirmed that the oxygen content on the worn surface increased significantly at high Cu content (x = 0.9) and high load (15 N), indicating that a lubricating oxide layer was formed and the alloy wear rate was reduced. With rising Cu content, the wear mechanism gradually changes from abrasive wear to oxidation wear. The oxide layer formed by the oxidation reaction during the friction process will hinder the wear of the HEAs and improve the alloy wear resistance.
10.1016-j.jmrt.2025.04.305	-1		Cu-15Ni-8Sn alloy stands out as a superior alternative to toxic and expensive Cu-Be alloys, due to its high strength and excellent corrosion resistance, particularly in applications such as deep-sea pipelines, bearings, and electronics in marine engineering. In this work, effect of boron on the mechanical properties and corrosion behavior of Cu-15Ni-8Sn alloy has been investigated. It was indicated that the precipitation of the second phase Ni6.67SnB2 can significantly inhibit the formation and growth of discontinuous precipitates. The higher content of elemental boron, the greater the number of the second phase under the condition of controlling the amount of boron added in this experiment. This leads to a subsequent rise in hardness, with the highest recorded hardness reaching 368 HV. The alloy also exhibits commendable tensile strength, with the ultimate tensile strength, elongation, and yield strength enhanced to 1.08 GPa, 14.3 %, and 862.7 MPa, respectively. Furthermore, the corrosion resistance of the Cu-15Ni-8Sn alloy was demonstrated to improve by electrochemical corrosion test after the introduction of boron.
10.1016-j.jmrt.2025.04.309	-1		The Cu-0.8Fe-0.2Mg and Cu-0.8Fe-0.2Mg-0.2Cr alloys were investigated using hot compression experiments at 600-950 degrees C and 0.003-10 s-1 strain rates. The effects of Cr addition on the microstructure and recrystallized behavior of the Cu-0.8Fe-0.2Mg alloy were characterized by electron backscatter diffraction (EBSD) and transmission electron microscopy (TEM). Experimental results indicated that Cr significantly increased the flow stress of the Cu-0.8Fe-0.2Mg alloy. The established constitutive equations revealed that the activation energy of the Cu0.8Fe-0.2Mg-0.2Cr alloy was 16.84 % higher than that of the Cu-0.8Fe-0.2Mg alloy. Microstructure analysis demonstrated that the addition of Cr decreased the percentage of high-angle grain boundaries (HAGBs), which inhibited the dynamic recrystallization (DRX) of the Cu-0.8Fe-0.2Mg-0.2Cr alloy. At 800 degrees C and 0.01 s-1, the texture content of Cu-0.8Fe-0.2Mg alloy was primarily composed of Cube, Brass, and S textures. After chromium was added, the texture became predominantly Brass. TEM results revealed that deformation at 800 degrees C and 0.01 s-1 led to alpha-Fe precipitate in the Cu-0.8Fe-0.2Mg alloy, which transformed into the alpha-(Fe, Cr) with Cr addition. This study provides insights into the high-temperature deformation and microstructure evolution of Cu-Fe-Mg alloys.
10.1016-j.jmrt.2025.05.100	14	strength; properties; conductivity; electrical; mechanical; cu-; grain; mpa; electrical conductivity; aging; precipitation; phase; mechanical properties; tensile; phases	A novel two-step sintering strategy is developed for the Cu-Ni + B4C system, separating the densification and insitu reaction stages, to fabricate (Ni2B + C)/Cu composites. In the first step, the Cu-Ni + B4C powder mixture is rapidly densified into compacted blocks via hot-pressing sintering. In the second step, these blocks are transferred to a pressure-less sintering furnace to promote the in-situ reaction between Ni and B4C. Experimental studies were conducted on the densification and in-situ reaction processes, as well as the properties of the resulting composites. Kinetic analysis revealed that the two-step sintering strategy effectively enhances densification and provides precise control over the size and distribution of the reinforcing phase. Compared to the traditional one-step hot-pressing sintering, the composites fabricated using the two-step strategy exhibit significant improvements of 15.4 % in tensile strength, 15.0 % in fracture elongation, 13.4 % in hardness, and 13.1 % in electrical conductivity. The in-situ reaction of Cu-Ni + B4C system is predominantly governed by interface control, with an activation energy of 76.7 kJ/mol, which is higher than that of traditional age-hardening alloys. Future research should focus on exploring methods to reduce the reaction activation energy of this system. The two-step sintering strategy holds promise as an effective method for large-scale industrial production of in-situ composites.
10.1016-j.jmrt.2025.05.183	-1		Metals are prone to cracking during processing, and the existence of cracks reduces the mechanical properties and service life. Therefore, molecular dynamics simulation method in this study is used to explore the initiation and propagation mechanism of Ni-Cu alloy cracks, so as to improve their mechanical properties. The results show that the intrinsic stacking faults (ISFs) were generated at the torsional end, resulting in the emission of dislocations and the initiation of shear transition zones (STZs). In the yielding stage, the rapidly growing ISFs led to the initiation of a large number of dislocations. At this time, STZs formed shear bands which caused the model to yield. The ISFs led severe lattice mismatch, increased dislocation density, and formed a large number of dislocation entanglements, thereby promoting the formation of cracks. The number and area of cracks rapidly increased during the plastic deformation stage, which eventually led to irrecoverable fracture of the material. The number and area of cracks are the largest at a high twisting rate. High Ni content can increase the yield strength and reduce the number of cracks. The study employed the construct surface mesh method to establish the relationship between shear bands, ISFs, dislocations, and cracks. The study investigates the mechanisms of crack initiation and propagation, providing a theoretical basis for optimizing the preparation process of Ni-Cu alloy and enhancing its mechanical properties.
10.1016-j.jmrt.2025.05.220	14	strength; properties; conductivity; electrical; mechanical; cu-; grain; mpa; electrical conductivity; aging; precipitation; phase; mechanical properties; tensile; phases	To address the challenge of simultaneously achieving high electrical conductivity and strength in Cu-Ti alloys, a Cu-3Ti-0.5 Mg-1Sn (wt. %) alloy was designed. The alloy underwent to, 60 % cold rolling, aging at 380 degrees C for 6000 min, 60 % cold rolling, and aging at 350 degrees C for 6000 min, exhibited excellent overall properties, with a tensile strength of 1137 MPa and an electrical conductivity of 25.2 %IACS. The addition of Sn leads to the formation of Ti3Sn, which improves the electrical conductivity of the alloy. The addition of Mg suppressed the formation of the (3'-Cu4Ti phase, thereby maintaining the alloy's high strength . The dislocations induced by cold rolling served as heterogeneous nucleation sites for the (3'-Cu4Ti phase. Long-term aging treatment at low temperatures after cold rolling suppresses the recovery and recrystallization and promotes the formation of the nanoscale (3'-Cu4Ti phase, which pins the dislocation and promotes dislocation multiplication. The interaction between dislocations and (3'-Cu4Ti phases during thermal mechanical treatment is the key to improving the overall performance of alloys. The alloy prepared in this study meets the requirement of connectors.
10.1016-j.jmrt.2025.05.239	-1		Cu-Sn electrodeposited coatings are widely used for decorative, corrosion-resistant, and wear-resistant purposes, especially in electronics, automotive, and aerospace industries. This study investigated the effect of cellulose nanocrystals (CNC), extracted from cotton by acid hydrolysis, as an additive at concentrations from 0 %v/v to 7.5 %v/v in a Cu-Sn electrolyte bath . The morphology, composition, and structure of the coatings were analyzed using scanning electron microscopy with energy-dispersive X-ray spectroscopy (SEM-EDS), X-ray diffraction (XRD), and roughness measurements. Wettability was evaluated through contact angle measurements. CNC incorporation led to more compact coatings with reduced roughness. Current efficiency increased with 1 %v/v and 2.5 %v/v CNC, indicating reduced energy consumption during electrodeposition. Contact angles rose from 95 degrees to 106 degrees and 126 degrees with 1 %v/v and 2.5 %v/v CNC, showing enhanced hydrophobicity. Corrosion resistance was assessed in 3.5 wt% NaCl solution using potentiodynamic polarization and electrochemical impedance spectroscopy (EIS), with the best performance and highest tin content observed at 1 %v/v CNC. Microhardness also increased with CNC addition, reaching its highest value at 7.5 %v/v. These findings highlight CNC as a lowcost and sustainable additive to enhance the properties of Cu-Sn coatings.
10.1016-j.jmrt.2025.05.264	14	strength; properties; conductivity; electrical; mechanical; cu-; grain; mpa; electrical conductivity; aging; precipitation; phase; mechanical properties; tensile; phases	This study investigates the effect of Fe content ranging from 0 to 0.6 wt% on the microstructure and properties of Cu-3Ti alloys. In the forged state, the alloy exhibits an equiaxed grain structure. When the Fe content is 0.1 wt%, the grain size increases to 31.39 mu m, and when the Fe content is 0.6 wt%, the grain size decreases to 13.76 mu m. The electrical conductivity remains stable at approximately 13 % IACS. The addition of Fe reduces the solubility of Ti in Cu, with some Ti atoms being replaced by Fe or forming FeTi phases with Fe, which promotes the precipitation of the beta '-Cu4Ti phase, thereby increasing the hardness with increasing Fe content. At 0.6 wt% Fe, the hardness reaches 255.34 HV0.2. After solution treatment at 880 degrees C for 2 h, the grain size gradually refines with increasing Fe content. However, the addition of Fe results in the formation of FeTi precipitates, which reduces the solubility of Ti in the matrix, leading to softening of the alloy. A 60 % cold-rolling deformation transforms the microstructure into a fibrous grain structure, resulting in a decrease in electrical conductivity but an increase in hardness. Aging treatment indicates that the Cu-3Ti-0.2Fe alloy reaches optimal performance after aging at 450 degrees C for 120 min, with a peak hardness of 345.18 HV0.2, electrical conductivity of 11.14 % IACS, and tensile strength of 1085 MPa. This balance of properties is attributed to the controlled precipitation of the beta '-Cu4Ti phase and the evolution of the dislocation substructure influenced by Fe.
10.1016-j.jmrt.2025.06.094	-1		The materials used in precision instruments need to withstand temperature variations that causes dimensional variations due to thermal expansion (TE). To address this issue, mechanical metamaterials made from two materials with different TE have been proposed. However, fabricating such structures using additive manufacturing is challenging because it requires the simultaneous operation of two lasers or nozzles. Advanced materials, such as shape memory alloys (SMA)s, can achieve negative thermal expansion (NTE) through modifications in composition and microstructure, but their development is typically limited to single components. In pursuit of this objective, this study aims to provide valuable insights into the relationship between the shape memory effect (SME) and unit cells designed with straight (stretching-dominated) and curved (bending-dominated) beams at various angles between the beams (2 beta) ranging from 40 degrees to 60 degrees. The focus is on how these designs impact dimensional variations for NTE applications. NTE lattices made of high-temperature Cu-Al-Ni SMA were subjected to a thermal load of 400 K. The results indicated that larger angles in straight beams led to a softening effect, reducing the SME and size stability. In contrast, curved beams at larger angles demonstrated stable SME and maintained size stability due to the influence of bending moments and the reorientation of martensite. For beams at lower angles, heat radiation initially improved SME and size stability by promoting the reversion of remnant martensite back into austenite. However, the stress gradients in cells with curved beams at these angles resulted in twin disconnection, leading to decreased SME and size stability.
10.1016-j.jmrt.2025.06.192	14	strength; properties; conductivity; electrical; mechanical; cu-; grain; mpa; electrical conductivity; aging; precipitation; phase; mechanical properties; tensile; phases	The study examines the impact of Tm addition on the microstructural change and precipitation behaviour in Cu3.5Ti alloy subjected to cold rolling and aging. The findings demonstrate that spinodal and dislocation strengthening emerge as the primary strengthening mechanisms in both Tm-added and Tm-free Cu-Ti alloys during the peak-aging stage, resulting in an impressive strength exceeding 900 MPa. However, with prolonged aging, a significant softening occurs in the alloys, attributed to the recovery of dislocations, a decrease in Ti solute atoms, and the growth of DP colonies. The Tm addition effectively suppresses the discontinuous precipitation. The Tm-added alloy demonstrates greater strength than that of the Tm-free alloy for the same aging time, primarily due to the lower volume fraction of the DP colonies. Additionally, the impurity scattering effect within the DP colony is weaker than that in the deformed grains. The inhibiting effect of Tm on discontinuous precipitation results in a slower growth rate of the DP colonies, which facilitates a slower increase in electrical conductivity in the Tm-added alloy compared to the Tm-free alloy.
10.1016-j.jmrt.2025.07.125	-1		Despite the excellent electrical and thermal conductivities of low-beryllium copper alloys, the limited mechanical properties severely impede their widespread applications. Here, dual plastic deformation treatments via rolling and ultrasonic surface modification are conducted to the matrix and surface of the Cu-0.2Be-1.0Ni alloy, followed by aging. It is found that, the large plastic deformation is introduced into the alloy and especially a 200 mu m deep gradient deformation layer from the interior to surface can be observed with gradually refined grains, increasing dislocation density and decreasing precipitates. These microstructural characteristics confer the alloy a high tensile strength of 894.7 MPa, elongation of 18.3 % and electrical conductivity of 60.1 % IACS. Analyses reveal that, in the alloy interior, the large plastic deformation promotes the generation of dense and coherent precipitates, fundamentally contributing to the high strength and electrical conductivity. Concurrently, in the alloy surface layer, the greatly refined grains mitigate stress concentration and the gradient heterostructures suppress microcrack propagation, which further improve the alloy strength and elongation. This work may provide an alternative approach to alleviate the enduring trade-off between strength and conductivity in copper alloys.
10.1016-j.jmrt.2025.07.157	-1		Explosively welding alloys at the solid-solutioned state and tuning composite properties by processing later were an alternative way than casting to make heavy components using small plates of better uniformity and property, but specific knowledge was lacking in treating these age-hardenable composites. Herein, microstructures and properties of such a Cu-Ni-Si-Cr alloy composite were investigated after cold rolling and aging. The pores were gradually closed by deformation in the interface molten zones without forming cracks. After peak aging, an amount of interfacial grains were already recrystallized under the greatly accumulated strain energy, and the hardness, strength, ductility and thermal conductivity of the rolled composites were comparable or even higher than those of the counterpart with the beneficial effects of deformation on reducing pores and generating microscopical defects to improve the precipitation efficiency. For the peak-aged composite, quantitative analysis indicated grain boundary, dislocation and precipitate hardening as the strongest strengthening mechanisms for the core interface, while the latter two for elsewhere, and the interface hardness was the lowest due to the severely-coarsened precipitates aided by the defects, especially the nanograin boundaries. Treatment and procedure optimization for making large components with explosive welding was discussed based on the results.
10.1016-j.jmrt.2025.07.170	14	strength; properties; conductivity; electrical; mechanical; cu-; grain; mpa; electrical conductivity; aging; precipitation; phase; mechanical properties; tensile; phases	In this study, a Cu-Al alloy was synthesized in situ via a direct energy deposition (DED) process by mixing aluminum alloy with CuNi2SiCr copper alloy. The microstructure, microhardness, and cavitation erosion behavior of the as-built DED samples were systematically investigated. After 10 h of exposure to cavitation erosion in 3.5 wt% NaCl solution, the as-built sample exhibited a weight loss rate of 1.47 mg/h, which is a reduction of 43.7 % compared to that of conventional cast nickel-aluminum bronze. The outstanding performance of the as-built sample is primarily attributed to its combination of the high-hardness dispersed petal-like gamma 2 and beta 1 phases. Additionally, its nanotwin martensitic structure and numerous nanoprecipitates further enhanced its ability to suppress plastic deformation and crack formation during cavitation erosion.
10.1016-j.jmrt.2025.07.192	14	strength; properties; conductivity; electrical; mechanical; cu-; grain; mpa; electrical conductivity; aging; precipitation; phase; mechanical properties; tensile; phases	Optimal interfacial bonding coupled with outstanding strengthening efficiency of reinforcement remains the cornerstone for developing high-performance Cu matrix composites. This study focuses on modulating both interface characteristics and microstructural architecture through in-situ processing, aiming to achieve a strength-conductivity balance in Cu matrix composites. Fabricated via direct current resistance sintering, the in situ TiB2/Cu composites exhibit increasing yield strength from 174 MPa to 388 MPa with increasing TiB2 content, achieving a 155.9 %-470.6 % enhancement over pure Cu while maintaining room-temperature thermal conductivity exceeding 200 W/m & sdot;K. Notably, these in-situ composites achieve superior strength-conductivity synergy compared to both conventional Cu matrix composites and Cu alloys reported in existing literature. This is attributed to the in-situ process regulation achieving: semi-coherent interfacial bonding, grain refinement (98 % refinement), dislocation strengthening (32.6-fold multiplication in dislocation density), and effective load transfer. Complementary mesomechanical simulations demonstrate that composite damage primarily originates from stress-strain concentration within the interparticle matrix regions, with matrix ductile fracture dominating the failure mode, and no significant interfacial debonding observed. These findings establish a theoretical framework for designing Cu matrix composites with exceptional strength-conductivity properties.
10.1016-j.jmrt.2025.08.015	14	strength; properties; conductivity; electrical; mechanical; cu-; grain; mpa; electrical conductivity; aging; precipitation; phase; mechanical properties; tensile; phases	Cu-Ni alloys are widely used in high-performance applications, such as in nuclear reactors, spacecraft, and other extreme environments, due to their excellent mechanical properties. However, under extreme irradiation conditions, these alloys undergo significant degradation in their microstructure and mechanical properties, which affects their long-term performance. This study investigates the effects of irradiation on the microstructure and mechanical properties of Cu-Ni alloys using molecular dynamics (MD) simulations, focusing on the displacement cascade process under varying temperatures, Primary Knock-on Atom (PKA) energies, crystal orientations, and Ni contents. The results show that higher temperatures facilitate the recombination of interstitial atoms and vacancies. Thereby reducing the number of Frenkel defect pairs in the steady state, while increasing PKA energy significantly increases the number of defect pairs due to more intense cascade collisions. Additionally, the study shows that defects exhibit different behaviors in the [100], [110], and [111] orientations, highlighting the anisotropic nature of Cu-Ni alloys. Tensile simulations indicate that although irradiation reduces the yield strength of Cu-Ni alloys, alloys with higher Ni content exhibit a smaller decrease in yield strength, especially after irradiation, suggesting that increasing Ni content plays a significant role in enhancing the alloy's irradiation resistance and maintaining mechanical performance under irradiation conditions. This study explores the effects of temperature, PKA energy, crystal orientation, and Ni content on irradiation-induced damage in Cu-Ni alloys, aiding the development of radiation-resistant materials and providing a theoretical foundation for improving the mechanical stability and performance of materials used in extreme irradiation environments.
10.1016-j.jmrt.2025.08.038	14	strength; properties; conductivity; electrical; mechanical; cu-; grain; mpa; electrical conductivity; aging; precipitation; phase; mechanical properties; tensile; phases	With the rapid advancement of the high-end electronic information industry, there is an increasing demand for metallic wires featuring ultra-fine diameters and high strength . Due to their superior strength and plastic deformability compared to pure copper wires, Cu-Ag alloy wires have attracted significant attention. In this study,Cu-20Ag alloy wires with various diameters were fabricated, and the evolution of their microstructure and twinning characteristics under large cumulative deformation was systematically investigated. The results show that the as-cast Cu-20Ag alloy rod exhibits a continuous eutectic network structure. As the wire diameter decreases, this network-like grain structure gradually transforms into fibrous grains. When the wire reaches the micron-scale, significant mutual diffusion between the Cu and Ag phases occurs, resulting in the formation of an abnormal interfaces induced by mechanical alloying. With further deformation, the Ag phase thickness is reduced, interdiffusion between Cu and Ag phases becomes more pronounced, and the interaction with twinning becomes increasingly significant. Moreover, cumulative deformation leads to a gradual refinement in both the twin width and twin boundaries within the Cu-20Ag wires. These findings provide theoretical insights for the development of ultrafine Cu-Ag wires and help to bridge the research gap in understanding the extreme deformation mechanisms of Cu-Ag alloys with high silver content.
10.1016-j.jmrt.2025.08.078	14	strength; properties; conductivity; electrical; mechanical; cu-; grain; mpa; electrical conductivity; aging; precipitation; phase; mechanical properties; tensile; phases	This work synthesized Cu-Y2O3 alloy via mechanical alloying and spark plasma sintering, and the impact of heat treatment at various stages of ball milling on the microstructure, mechanical, and physical properties of Cu-Y2O3 alloy was systematically examined. Results show that heat treatment during initial ball milling causes Y2O3 agglomeration, resulting in an increase in particle size to 112.8 +/- 19.6 mu m. In contrast, heat treatment during the middle and late stages of ball milling effectively refines powder particles, enhancing material density and overall properties. Furthermore, post-heat treatment, Y2O3 particles can be further refined through ball milling, reducing crystal particle size from 6.4 +/- 2.8 nm to 4.2 +/- 1.7 nm. This process mitigates cold welding effects, prevents local enrichment, and ensures a more uniform distribution of Y2O3 particles.
10.1016-j.jmrt.2025.08.156	14	strength; properties; conductivity; electrical; mechanical; cu-; grain; mpa; electrical conductivity; aging; precipitation; phase; mechanical properties; tensile; phases	This study develops a novel single-step drawing and multi-stage rolling composite process for manufacturing high-performance ultrathin copper (Cu) strips, systematically exploring microstructure evolution and mechanical property regulation mechanisms. Finite element modeling (FEM) conducted via ABAQUS revealed pronounced spatiotemporal heterogeneity in stress-strain field distributions, characterized by a marked escalation in longitudinal (x-axis) tensile stress during the secondary and tertiary rolling phases, whereas transverse (y-axis) compressive stresses exhibited progressive stabilization. Quantitative microstructural characterization evidenced a monotonic reduction in grain size from 22.88 mu m (as-received Cu wire) to 9.31 mu m (post-deformation), attributable to dynamic recrystallization mechanisms. Notably, post-annealing microstructural evolution analysis identified abnormal grain growth as the dominant factor governing the strength degradation in incremental differential speed rolling and recrystallization annealed (IDRRRA) specimens Comparative mechanical testing showed that the IDRRRA-sample exhibited lower tensile yield strength (TYS: 85.39 MPa) and ultimate tensile strength (UTS: 403.65 MPa) but superior elongation (58.1 %) compared to I-sample. Visco-plastic self-consistent (VPSC) simulations revealed that although both alloys exhibited {111}<110> slip-dominated deformation during tension, the {111}<112> twinning in the IDRRRA specimen was delayed during the later stages of tensile deformation compared to I-sample.
10.1016-j.jmrt.2025.08.185	14	strength; properties; conductivity; electrical; mechanical; cu-; grain; mpa; electrical conductivity; aging; precipitation; phase; mechanical properties; tensile; phases	This study employs DFT and experimental approaches to investigate Ag doping effects on Fe/Cu interfacial properties. Theoretical analysis shows that the negative formation energy of Ag at the Fe/Cu interface and its high work of adhesion confirm its thermodynamic spontaneity and the enhanced interfacial bonding capability. Experimental characterization reveals that 1 wt% Ag addition effectively refines the Cu grain size due to the precipitation of fine Ag particles, which pin the grain boundaries and impede grain coarsening, while suppressing interfacial embrittlement via Ag segregation at the delta-Cu3Sn Sn phase boundaries. The optimal Ag concentration (1 wt%) simultaneously increases the diffusion layer thickness from 2.85 mu m to 6.49 mu m and enhances the interfacial shear strength by 58.3 %. Tribological evaluation shows that the optimal Ag doping level (1 wt%) significantly improves wear resistance, whereas excessive Ag content leads to matrix softening and performance degradation. These findings provide a comprehensive understanding of Ag's multiscale modification mechanism in Cu12Sn-2Ni-xAg/42CrMo composites, linking atomic-scale interfacial bonding, microstructural evolution, and macroscopic mechanical properties, and offering valuable guidance for the design of high-performance metal composites.
10.1016-j.jmrt.2025.08.229	14	strength; properties; conductivity; electrical; mechanical; cu-; grain; mpa; electrical conductivity; aging; precipitation; phase; mechanical properties; tensile; phases	In this study, Cu-3.44Ni-0.86Si-xSn (x = 0, 1, 2 wt%) alloy strips were fabricated via two different processing routes, namely the traditional preparation (TP) process and the improved preparation (IP) process. The microstructural evolution, precipitation behavior, and stress relaxation resistance of the alloys were systematically investigated. The results show that the precipitation of Ni2Si during pre-aging facilitates grain refinement and increases dislocation density during subsequent cold rolling. Compared with the TP process, the IP-processed alloys exhibit finer and more uniform microstructures, higher hardness, and superior stress relaxation resistance. Notably, the Sn2 alloy subjected to the IP process demonstrates the best performance, with a stress relaxation rate of only 9.5 % after 15 h at room temperature. This enhancement is attributed to the combined pinning effect of the densely distributed Ni2Si phases and the additionally precipitated Ni3Si phases promoted by Sn, which effectively hinder dislocation motion. These findings reveals a previously unreported dual-phase precipitation mechanism, in which Sn addition promotes the simultaneous formation of Ni2Si and Ni3Si phases through modulation of solute distribution. Furthermore, this work proposes a novel alloy design strategy that integrates composition-induced phase control with deformation sequence optimization to enhance the stress relaxation resistance of Cu-Ni-Si based alloys.
10.1016-j.jmrt.2025.08.288	14	strength; properties; conductivity; electrical; mechanical; cu-; grain; mpa; electrical conductivity; aging; precipitation; phase; mechanical properties; tensile; phases	Tribocorrosion behavior of materials under deep-sea conditions remains poorly understood, especially for polymer-metal composites. The tribocorrosion behavior and failure mechanism of Cu(Zinc-copper-tin alloy)-NBR (Nitrile Butadiene Rubber) under deep-sea hydrostatic pressures was investigated using in-situ triboelectrochemical testing combined with surface analysis techniques. Results indicates that after wear initiation, the open-circuit potential of NBR/Cu shifts negatively, and the self-corrosion current density increases. With prolonged friction, NBR transfers to the copper matrix, forming a protective transfer layer that mitigates Cu corrosion under water lubrication. The synergistic effect is predominantly driven by Cl--induced enhancement of mechanical wear, with hydrostatic pressure amplifying this interaction. This study provides theoretical guidance for developing durable surface protection strategies in deep-sea engineering applications.
10.1016-j.jmrt.2025.09.076	-1		50Cu-40Fe-10Ti (wt. %) ternary alloy was synthesized using mechanical milling technique, aimed to enhancing both its solubility and magnetic behavior. A systematic investigation was conducted to explore the role of Ti content on the extent of Fe solubility within Cu matrix and its consequent impact on the magnetic behavior of the alloy. The structural, morphological, and magnetic properties of the alloy were comprehensively characterized using a combination of advanced analytical techniques including X-ray diffraction (XRD), differential thermal analysis (DTA), high-resolution transmission electron microscopy (HRTEM), and superconducting quantum interference device (SQUID) measurements. According to the findings of the current investigation, the synthesized alloy was completely soluble in solid solution after 50 h of milling. Following annealing at 450 degrees C for 1 h, the resulting ball-milled alloy consisted predominantly of elemental copper, iron, and titanium, along with their corresponding oxides, as determined by quantitative phase analysis using X-ray diffraction. Moreover, the magnetic characteristics viz., coercivity, remnant magnetization and saturation magnetization attain their maximum values at around 401 Oe, 13.9 emu/gm and 49 emu/gm, respectively, obtained in the ball milled alloy after annealing at 450 degrees C for 1 h . These results demonstrate a tunable balance between magnetic hardness and saturation. Simulation revealed a Curie temperature of 175 K for the alloy, marking the transition from ferromagnetic to paramagnetic behaviour and defining the temperature range for stable magnetic performance. By optimizing mechanical milling and annealing parameters, ternary alloys can be tailored to meet the specific requirements of diverse technological applications. This work provides new insights about phase evolution, crystallite growth and strain relaxation directly influence magnetic behavior, such as saturation magnetization and coercivity.
10.1016-j.jmrt.2025.09.120	14	strength; properties; conductivity; electrical; mechanical; cu-; grain; mpa; electrical conductivity; aging; precipitation; phase; mechanical properties; tensile; phases	The influence of Zr addition on the microstructural evolution, recrystallization behavior, and mechanical properties of Cu-Fe alloys was investigated. Addition of 1 wt% Zr led to formation of Fe2Zr and ZrO2 phases; this process resulted in grain refinement and increased dislocation density. These precipitates effectively hindered dislocation motion and contributed to strengthening mechanisms. Zr addition significantly increased the yield strength and ultimate tensile strength across a wide range of annealing temperature T-ANN. The strengthening contributions from grain-boundary refinement, work hardening, and precipitation were substantially increased, so the alloy was strengthened by similar to 141.71 MPa at T-ANN = 400 degrees C. Additionally, at elevated T-ANN, Zr suppressed recrystallization of the Cu phase while accelerating that of the Fe phase, so the mechanical properties varied with T-ANN. These results provide new insights to guide design of high-strength, thermally stable Cu-Fe alloys for advanced structural and electronic applications.
10.1016-j.jmrt.2025.09.126	14	strength; properties; conductivity; electrical; mechanical; cu-; grain; mpa; electrical conductivity; aging; precipitation; phase; mechanical properties; tensile; phases	Copper, as a key conductor material for high-power devices, is severely restricted in high-temperature environments and high-end applications due to its low strength and insufficient high-temperature stability. In this study, Cu-Al-Sc alloys with different contents were prepared based on the regulation strategy of an Al/Sc atomic ratio of 3, and the effects of microalloying with different Al and Sc contents on the microstructure and properties of pure copper were systematically investigated using OM, EBSD, and TEM. The results show that the Cu0.021Al-0.012Sc alloy has the best comprehensive performance. In the cold-rolled state, its electrical conductivity, hardness, and tensile strength are 94.4 % IACS, 139.8 HV, and 403 MPa, respectively. After hightemperature treatment at 850 degrees C for 30 min, the electrical conductivity and hardness are 97.6 % IACS and 86.4 HV, respectively. The grain size is refined from 237.49 mu m to 77.88 mu m, and the softening temperature is increased from 165 degrees C to 515 degrees C. The significant increase in softening temperature is mainly attributed to a dual mechanism: Firstly, the solid solution of Al and Sc causes lattice distortion and hinders dislocation slip, while Sc segregation at grain boundaries reduces grain boundary energy and inhibits recrystallization nucleation and growth . Secondly, the precipitation of oxide phases pins grain boundaries and dislocations, inhibiting the transformation of deformation texture (Brass/S) to recrystallization texture (Cube/Goss), and the inhibitory effect increases with the increase of Sc content, thereby significantly improving the anti-softening performance of pure copper.
10.1016-j.jmrt.2025.09.254	-1		In this study, flake graphite (C) was incorporated into the Cu-3Zr alloy, and Cu-3Zr alloys with xC (x = 0.2, 0.4, 0.6 wt%) were obtained by powder metallurgy together with two-stage thermomechanical processing. The phase structure and constituents were characterized by XRD, SEM and TEM, and the electrical conductivity and mechanical properties were tested. The strengthening and conductive mechanisms were discussed as well. Compared with the as-sintered Cu-3Zr alloy, the elongation increases and then decreases with increase of C content for the as-sintered Cu-3Zr-xC composites whereas the ultimate tensile strength progressively decreases. The electrical conductivity is increased by 9.84 %, 13.11 % and 16.39 %, respectively. Compared with the asdrawn Cu-3Zr alloy, the ultimate tensile strength of as-drawn Cu-3Zr-0.2C is decreased by 4.3 % while the elongation is increased by 44.4 %, and the electrical conductivity is increased by 5.4 %. It demonstrates that graphite addition and thermomechanical processing facilitates the enhancement on the comprehensive properties. At a C content of 0.2 wt%, an optimal balance between mechanical properties and electrical conductivity is achieved, with an ultimate tensile strength of 658 MPa, yield strength of 573 MPa, elongation of 6.5 %, and electrical conductivity of 78 %IACS. The microstructural analysis reveals that the secondary particles present different distribution for the Cu-3Zr alloy and Cu-3Zr-0.2C composite. For the Cu-3Zr alloy, the coarse CuxZry intermetallic compounds are distributed randomly at the grain boundaries and within the Cu grains, whereas fine ZrC particles are primarily distributed along grain boundaries for the Cu-3Zr-0.2C composite. In addition, ZrC particles in the Cu-3Zr-0.2C has the lower volume fraction than CuxZry in the Cu-3Zr, and the addition of C can purify the Cu matrix by virtue of the strong reaction tendency between C and Zr. Moreover, the directed Cu grains can provide fast channel for electrons transport and special loading transferring effect. As a result, although the strength decreases, the electrical conductivity and elongation increase by introducing C into ZrC, and the extrusion and drawing are also benefit for both mechanical and electrical properties.
10.1016-j.jmrt.2025.10.041	-1		The internal structure, interface width, and residual internal stress distribution of composite materials affect their fatigue properties, and thus their service life. Copper-niobium multi-filaments nanocomposite wire, produced through bundled drawing, possess a high-density, low-energy copper-niobium interface and a nanostructured filament. As wires for winding magnetic coils, they are subjected to lateral cyclic loads in a bent state during service. In this study, the two types of copper-niobium nanocomposite wires produced via jelly-rolling-bundled drawing and melting-bundled drawing were taken as the research objects. Cyclic bending deformation tests with different applied bending load ratios of 30 %, 50 %, and 70 % are carried out on them to study the fatigue properties and fracture behavior of the copper-niobium nanocomposite wires. The effect law of different load ratios on the fatigue cycles were analyzed, and the effect mechanisms of the internal microstructure, interface density and width, and residual stress distribution at the interface on crack propagation and fracture behavior during cyclic deformation process were revealed. The results indicated that, in copper-niobium heterostructured composite wires, the tensile stress zone above neutral axis exhibits a mix of ductile and brittle fracture morphologies, along with fatigue striations. In contrast, the tensile stress zone of copper-niobium alloy composite wire predominantly exhibits brittle fracture, with observable brittle fatigue striations, cleavage steps, and fanlike river patterns. The jelly-rolling composite structure with alternating copper/niobium layers reduce the residual stress at the interface, while large plastic deformations induce twinning within the copper filaments. These effectively transfers gradient stresses and delays crack growth, leading to superior cyclic bending fatigue performance. At a 30 % bending stress level, the fatigue life of the copper-niobium heterogeneous composite material reaches 1.7 x 106 cycles.
10.1016-j.jmst.2013.06.010	11	glass; bulk; metallic; bulk metallic; gfa; bmg; glassy; metallic glass; ability; bulk metallic glass; amorphous; addition; crystallization; mm; glass-forming	The glass-forming ability and the thermal stability of Cu45Zr45Al5Ni5 metallic glass were systematically investigated by the differential scanning calorimetry. The activation energies for the glass transition and the onset crystallization and the crystallization peak were calculated to be 255.1, 308.7 and 311.5 kJ/mol, respectively, while the corresponding liquid fragility was determined to be 23.4. By controlling the casting process, Cu45Zr45Al5Ni5 bulk metallic glass composite with the presence of ductile B2 CuZr phase was fabricated. The composite shows a pronounced plastic strain of 6.8 +/- 0.05% with obvious work hardening, which results from the formation of multiple shear bands and the deformation-induced martensitic transformation.
10.1016-j.jmst.2013.09.021	-1		Large-area bulk ultrafine grained (UFG) pure Cu was successfully prepared by multiple-pass overlapping friction stir processing (FSP) under additional rapid cooling. Overlapping FSP did not exert a significant effect on the microstructure and mechanical properties of the FSP UFG Cu. Similar average grain size was achieved in the transitional zone (TZ) of the multiple-pass FSP sample compared to that in the nugget zone of the single-pass FSP sample, and the TZ exhibited a strong {111} < 112 > type A fiber shear texture. Very weak softening occurred in the TZ of the multiple-pass FSP UFG Cu, resulting in a relatively uniform hardness distribution throughout the whole processed zone. A high yield strength of similar to 310 MPa and a uniform elongation of similar to 13% were achieved in the bulk FSP UFG Cu. This study provides an effective strategy to prepare large-area bulk UFG materials.
10.1016-j.jmst.2015.10.007	16	wear; composite; composites; powders; milling; particles; powder; wt; sliding; friction; hardness; matrix; mechanical; surface; properties	Some properties of the Fe-based P/M composites sintered and reinforced by infiltration with Cu-Sn alloy were described. It is shown that the hardness of the sintered material is 2.5 times lower, tensile strength is 1.7 times lower and the wear resistance is 2.5-3.3 times lower in comparison with those of the infiltrated material. The presence of pores on the friction surface of the sintered material affects the features of the wear process. Due to the specific morphology of copper in the infiltrated material, the phenomenon of selective mass transfer is observed and worn surfaces have a spongy-capillary texture. Copyright
10.1016-j.jmst.2017.09.008	13	clusters; atomic; glass; atoms; composition; dynamics; metallic; icosahedral; glasses; simulations; molecular; cu-zr; molecular dynamics; metallic glasses; structural	On the contrary to the common belief that glass formation is unfeasible near terminal intermetallic compound due to fast crystallization kinetics, here we present our findings that bulk metallic glasses are readily formed near intermetallic compounds, far away from the traditional region of glass forming near eutectics. While the intermetallic compounds themselves are not possible glass formers, bulk metallic glasses can be quenched compositionally neighboring the intermetallic compounds as close as 0.5 at%. Taking binary Cu-Zr as a model system, the phenomenon of two optimum glass forming compositions sandwiching the corresponding intermetallic compounds (Cu51Zr14, Cu10Zr7, CuZr, CuZr2 and Cu8Zr3) is observed consistently. This new scenario of intermetallic glass is verified by the thermodynamic principle that the alloy liquids neighboring the intermetallic compounds possess lower Gibbs free energy than that of the compounds themselves. Furthermore, the sluggish crystallization behavior of these liquids provides an additional kinetic explanation. (C) 2017 Published by Elsevier Ltd on behalf of The editorial office of Journal of Materials Science & Technology.
10.1016-j.jmst.2017.10.004	-1		Cu single crystals were subjected to dynamic compression plastic deformation to investigate orientation-dependent twinning. The experimental results showed that twinning is closely related to the ratio of the maximum Schmid factor for twinning partial (m(T)) to the maximum Schmid factor for perfect dislocation (m(S)), m(T)/m(S), rather than m(T). The twin volume fraction V-T increases with the m(T)/m(S) value and the most favorable orientation for twinning has the maximum m(T)/m(S) value (1.15). The relationships of m(T)/m(S) with both effective stacking fault energy gamma(eff) and threshold stress for twinning tau(T) were established for understanding orientation-dependent twinning. Further insights into the orientation-dependent twinning and guidance for developing bulk high density nanotwinned materials are provided. (C) 2017 Published by Elsevier Ltd on behalf of The editorial office of Journal of Materials Science & Technology.
10.1016-j.jmst.2019.10.038	0	solidification; phase; magnetic; magnetic field; undercooling; field; liquid; separation; peritectic; immiscible; cu-; dendrite; phase separation; microstructure; primary	The immiscible Cu-Fe alloy was characterized by a metastable miscibility gap. With the addition element Zr, the miscibility gap can be extended into the Cu-Fe-Zr ternary system. The effect of the atomic ratio of Cu to Fe and Zr content on the behavior of liquid-liquid phase separation was studied. The results show that liquid-liquid phase separation into Cu-rich and Fe-rich liquids took place in the as-quenched Cu-Fe-Zr alloy. A glassy structure with nanoscale phase separation was obtained in the as-quenched (Cu0.5Fe0.5)(40)Zr-60 alloy sample, exhibiting a homogeneous distribution of glassy Cu-rich nanoparticles in glassy Fe-rich matrix. The microstructural evolution and the competitive mechanism of phase formation in the rapidly solidified Cu-Fe-Zr system were discussed in detail. Moreover, the electrical property of the as-quenched Cu-Fe-Zr alloy samples was examined. It displays an abnormal change of electrical resistivity upon temperature in the nanoscale-phase-separation metallic glass. The crystallization behavior of such metallic glass has been discussed. (C) 2020 Published by Elsevier Ltd on behalf of The editorial office of Journal of Materials Science & Technology.
10.1016-j.jmst.2019.12.022	-1		The mixed nanostructure mainly consisting of nanotwins and nanograins was obtained in a solid solution CuCrZr alloy by means of dynamic plastic deformation at cryogenic temperature. After subsequent aging treatments, the precipitation of Cr at nanometer scale provided further strengthening and brought substantial recovery of electrical conductivity. The aged nanostructured CuCrZr alloy exhibited a high tensile strength of 832 MPa and a high electrical conductivity of 71.2% IACS. The details of precipitation tuned by nanotwin boundaries were demonstrated in this work. The combined strengthening of nanostructures and nanoprecipitates was discussed. (C) 2020 Published by Elsevier Ltd on behalf of The editorial office of Journal of Materials Science & Technology.
10.1016-j.jmst.2019.12.023	-1		Although Cu was studied extensively, the Hall-Petch relationship was mainly reported in the coarse-grained regime. In this work, fully recrystallized Cu specimens with a wide grain size regime of 0.51-14.93 mu m manifest a two-stage Hall-Petch relationship. There is a critical grain size of 3 mu m that divides stages I and II where the Hall-Petch slope k value are quite different. The stage II is supposed to be validified down to 100 nm at least by comparing with a Cu-Ag alloy. The critical grain size varies in different materials systems, and the underline mechanisms are discussed based on the dislocation glide modes. (C) 2020 Published by Elsevier Ltd on behalf of The editorial office of Journal of Materials Science & Technology.
10.1016-j.jmst.2020.03.052	-1		Ultrafine-grained (UFG)/nanocrystalline materials possess novel properties. Refining as-solidified grains of metals to the ultrafine and even nanometer scale by nanoparticles via slow cooling has been recently discovered. Here, we report that microparticles (CrB and CrB2) with surface nanofeatures can also enable ultrafine/nano grains via slow cooling. CrB/CrB2 microparticles, formed by coalescence of nanoparticles in Cu matrix, display surface nanofeatures, which induce substantial grain refinement and stabilization down to the ultrafine/nano scale. The UFG Cu/CrB and Cu/CrB2 samples exhibit exceptional thermal stability, comparable to UFG Cu induced by nanoparticles, without coarsening after annealing at 600 degrees C for 1 h . The microhardness, strengths, and Young's moduli of the Cu/CrB and Cu/CrB2 samples are significantly enhanced over pure Cu. This discovery has great potential to advance the mass production UFG/nanocrystalline for widespread applications. (C) 2020 Published by Elsevier Ltd on behalf of The editorial office of Journal of Materials Science & Technology.
10.1016-j.jmst.2020.11.043	-1		Copper alloy is widely used in high-speed railway, aerospace and other fields due to its excellent electrical conductivity and mechanical properties. High speed deformation and dynamic loading under impact load is a complex service condition, which widely exists in the field of national defense, military and industrial application. Therefore, the dynamic deformation behavior of the Cu-20Ag alloy was investigated by Split Hopkinson Pressure Bar (SHPB) with the strain rates of 1000-25000 s(-1), high-speed hydraulic servo material testing machine with the strain rates of 1-500 s(-1). The effect of strain rate on flow stress and adiabatic shear sensitivity was analyzed. The results show that the increase of strain rate will increase the flow stress and critical strain, that is to say, the increase of strain rate will reduce the adiabatic shear sensitivity of the Cu-20Ag alloy. The Cu-Ag interface has obvious orientation relationship with (111)(Cu)//(111)(Ag);((1) over bar 11)(Cu)//((1) over bar 11)(Ag); ((2) over bar 00)(Cu)//((2) over bar 00)(Ag) and [0 (1) over bar1](Cu)//[0 (1) over bar1](Ag) with the increase of strain rate. The increase of strain rate promotes the precipitation of Ag and increases the number of interfaces in the microstructure, which hinders the movement of dislocations and improves the stress and yield strength of the Cu-20Ag alloy. The concentration and distribution density of dislocations and the precipitation of Ag were the main reasons improve the flow stress and yield strength of the Cu-20Ag alloy. (C) 2021 Published by Elsevier Ltd on behalf of The editorial office of Journal of Materials Science & Technology.
10.1016-j.jmst.2021.01.034	-1		Aging treatment of Cu-based alloys is essential to enhance their strength that is desirable for their extensive engineering applications in electrical industry, whereas the underlying mechanism of strengthening is essential for massive manufacturing of these alloys. Here, the microstructure evolution of a supersaturated solid solution Cu-15Ni-8Sn-0.2Nb alloy aged at 400 degrees C for different time was characterized at atomic scale using state-of-the-art transmission electron microscopy (TEM) and the corresponding mechanical property was also measured. The results reveal that the modulated structure, DO22/L1(2) ordering, and discontinuous precipitation (DP) appeared in the advances of aging time. At the early stage of aging treatment, component modulation waves and satellite spots appeared from spinodal decomposition and the modulation wavelength was identified in the range of 1-7 nm. Subsequently the modulated structures formed -poor-rich solute regions, of which DO22 ordering was present in the Ni-poor region while L1(2) ordering appeared in the Ni-rich region. The sequence of ordering precipitates was further verified by density functional theory (DFT) simulations. Furthermore, orientation relationships and interfacial structures between DO22, L1(2) phases and the parent matrix were determined. The measured hardness of alloy reached a maximum value of 335 HV after aging for 120 min due to the coherence between the two ordering phases and matrix. These results illustrated the importance of aging on structural evolution and mechanical property of Cu-15Ni-8Sn alloy at various heat treatment stages, which could potentially help in manufacturing promising alloys for their extensive engineering applications. (C) 2021 Published by Elsevier Ltd on behalf of The editorial office of Journal of Materials Science & Technology.
10.1016-j.jmst.2021.02.013	-1		Grain size dependent strength, known as Hall-Petch relation, has been approved to be valid in crystalline metals and alloys. However, softening would eventually occur as grain size reduced into nanoscale that below a critical value. Hence, it is essential to find a way to break the strength limitation by avoiding the deformation mechanism transition from dislocation-mediated to grain-boundary-mediated processes. By replacing grain boundary (GB) of nanocrystalline Cu with graphene, in the present study, molecular dynamics simulations show that graphene-boundary (GrB) embedded GrB/Cu nanocomposites exhibit enhanced enlarged Hall-Petch slope with decreasing grain size. The absence of inverse-Hall-Petch relation and the extremely high strength derived at the GrB/Cu nanocomposites were interpreted by the high back stress and abundant dislocation activity that attributed from the high-degree of heterogeneous structure of the nanocomposites. (C) 2021 Published by Elsevier Ltd on behalf of The editorial office of Journal of Materials Science & Technology.
10.1016-j.jmst.2021.03.008	-1		Copper/steel is a typical bimetal functional material, combining the excellent electrical and thermal conductivity of copper alloy and the high strength and hardness of stainless steel. There has been recent interest in manufacturing copper/steel bimetal by directed energy deposition (DED) due to its layer-by layer method. However, cracks tend to form on the copper/steel interface because of the great difference in thermal expansion coefficient and crystal structure between copper and steel. In this work, interfacial characteristics and mechanical properties of the copper/steel bimetal were studied from one layer to multilayers. The laser power has a great influence on the Cu element distribution of the molten pool, affecting the crack formation dramatically on the solidification stage. Cracks tend to form along columnar grain boundaries because of the Cu-rich liquid films and spherical particles in the cracks. Crack-free and good metallurgical bonding copper/steel interface is formed at a scanning velocity of 800 mm/min and the laser power of 30 0 0 W. The ultimate tensile strength (UTS) and the break elongation (EL) of the vertically combined crack-free copper/steel bimetal are 238.2 +/- 4.4 MPa and 20.6 +/- 0.7%, respectively. The fracture occurs on the copper side instead of the copper/steel interface, indicating that the bonding strength is higher than that of the Cu-Cr alloy. The UTS of the horizontally combined crack-free copper/steel bimetal is 746.7 +/- 22.6 MPa, which is 200% higher than that of the Cu-Cr alloy substrate. The microhardness is 398.6 +/- 5.4 HV at the steel side and is 235.3 +/- 64.1 HV at the interface, which is 400% higher than that of the Cu-Cr alloy substrate. This paper advances the understanding of the interfacial characteristics of heterogeneous materials and provides guidance and reference for the fabrication of multi-material components by DED. (c) 2021 Published by Elsevier Ltd on behalf of Chinese Society for Metals.
10.1016-j.jmst.2021.03.049	15	aging; strength; conductivity; electrical conductivity; electrical; mpa; treatment; strengthening; degrees; cu-; cold; precipitation; tensile strength; tensile; iacs	In this paper, a novel Cu-1.5Ni-1.1Co-0.6Si-0.1Cr (wt%) alloy with high strength and electrical conductivity was designed. After aging, excellent properties of 857 +/- 12 MPa yield strength, 300 +/- 8 HV microhardness, 42.8 +/- 2.5% IACS conductivity, and 7 +/- 0.5% elongation were obtained. According to the atomic structure, part of Ni atoms in Ni2Si can be replaced by Co atoms to form nano-precipitates (Ni, Co)(2)Si. The alloy's high strength and conductivity are mainly attributed to the fine and uniformly distributed (Ni, Co)(2)Si and Cr nano precipitates. The alloy strength was also enhanced by twins, dislocations, and grain refining strengthening. Based on the investigations of deformation microstructure and the orientation relationship between the (Ni, Co)(2)Si precipitates and the Cu matrix, the main reason for elongation increase is attributed to the formation of deformation twins and the small lattice mismatch strain at the coherent interfaces of precipitates and the Cu matrix. (C) 2021 Published by Elsevier Ltd on behalf of Chinese Society for Metals.
10.1016-j.jmst.2021.06.043	6	grain; deformation; strain; strength; dislocation; cu-; tensile; size; ecap; grain size; sfe; ductility; hardening; high; stress	To clarify the work hardening discrepancy effect on the strengthening of laminated metals, we designed two laminated Cu/Cu4Zn and Cu/Cu32Zn samples with different layer thicknesses. Cu/Cu4Zn has larger work hardening discrepancy between two constituent layers relative to Cu/Cu32Zn, but the yield strengths of two CuZn constituents are comparable. Uniaxial tensile results suggest Cu/Cu4Zn with larger work hardening discrepancy exhibits a significant strengthening at early deformation stage while Cu/Cu32Zn possesses a better ductility. The underlying mechanisms for the strengthening effect are attributed to more geometrically necessary dislocations accumulated at interfaces and severer strain localization due to the larger work hardening discrepancy. ?? 2022 Published by Elsevier Ltd on behalf of The editorial office of Journal of Materials Science & Technology.
10.1016-j.jmst.2021.08.023	-1		Microbiologically influenced corrosion (MIC) is an unavoidable problem in several industries. Copper (Cu) and its alloys are widely used engineering materials. However, MIC of Cu remains a persistent chal-lenge to their performance and functional lifetime under aggressive environments. This study investi-gated nanosecond pulsed laser processing (LP), which may enhance the corrosion resistance of Cu. The microstructural evolution and corrosion behavior of LP-Cu in the presence of sulfate-reducing bacteria (SRB) were evaluated. Typical deformation-induced microstructural features of high-density dislocations were analyzed on the top surface of LP-Cu coupon. Electrochemical measurements suggested that LP-Cu coupons exhibited better corrosion resistance in SRB-inoculated solution compared with their original counterpart. The enhanced corrosion resistance by LP primarily resulted from the combined influences of compressive residual stress and work hardening in the surface. However, overlap percentage played a key role in improving corrosion resistance. LP produced optimal corrosion resistance at 50% overlap. There-fore, this study introduces a unique and an option for anticorrosion control in manufacturing processes and potentially implements it onto other materials to improve its microbial corrosion resistance through LP. (c) 2022 Published by Elsevier Ltd on behalf of The editorial office of Journal of Materials Science & Technology.
10.1016-j.jmst.2021.08.080	-1		Cu-0.57Cr-0.01Ca and Cu-0.58Cr-0.01Sr (wt%) alloys were fabricated and processed by thermo-mechanical treatment. Their mechanical and electrical properties and microstructure were investigated in detail and compared with those of a Cu-0.57Cr (wt%) alloy. The results showed that the softening resistance of the Cu-Cr alloy was significantly improved by the additions of Ca and Sr elements. Compared with the Cu-Cr alloy, the deformation microstructure of the Cu-Cr-Ca and Cu-Cr-Sr alloys was more difficult to recrystallize at elevated temperatures, and the Cr precipitates in the Cu-Cr-Ca and Cu-Cr-Sr alloys were smaller in size and had an FCC structure at any given aging state. The high strengths of the Cu-Cr-Ca and Cu-Cr-Sr alloys were mainly attributed to the dislocation strengthening provided by high-density dislocations and the precipitate strengthening provided by fine Cr precipitates. First-principles calculation showed that the segregations of Ca and Sr atoms at interface between Cr precipitates and copper matrix were favorable in energetics. This segregation effectively hindered the growth of Cr precipitates and significantly enhanced the pinning effect on the motion of dislocations and subgrain boundaries, eventually leading to the improvement in the softening resistance of the Cu-Cr alloy. (c) 2021 Published by Elsevier Ltd on behalf of Chinese Society for Metals.
10.1016-j.jmst.2021.09.063	6	grain; deformation; strain; strength; dislocation; cu-; tensile; size; ecap; grain size; sfe; ductility; hardening; high; stress	To probe a pathway to improve the low-cycle fatigue life of face-centered cubic (FCC) metals via grain boundary engineering (GBE), the tension-tension fatigue tests were carried out on the non-GBE and GBE Cu-16 at%Al alloys at relatively high stress amplitudes. The results indicate that the cyclic strain localization and cracking at grain boundaries (GBs) can be effectively suppressed, especially at increased stress amplitude, by an appropriate GBE treatment that can result in a higher resistance to GB cracking and a greater capability of compatible deformation. Therefore, the sensitivity of fatigue life to stress amplitude can be weakened by GBE, and the low-cycle fatigue life of Cu-16 at%Al alloys is thus distinctly improved. (c) 2022 Published by Elsevier Ltd on behalf of The editorial office of Journal of Materials Science & Technology.
10.1016-j.jmst.2021.10.012	-1		As a promising material for the new generation of high-speed railway contact wires, the comprehensive optimization of the electrical conductivity, strength, hardness and wear resistance of the Cu-Cr-Zr alloy has received extensive attention. In this paper, a high-performance Cu-1Cr-0.1Zr alloy with an ultimate tensile strength of 599.1 MPa, a uniform elongation of 8.6%, a microhardness of 195.7 HV0.2 and an electrical conductivity of 80.07%IACS was achieved by the continuous extrusion forming (CEF) and subsequent peak-aging treatment. The grain refinement strengthening, dislocation strengthening and precipitation strengthening are identified to be responsible for the excellent electrical and mechanical properties of Cu-Cr-Zr alloy. The wear behavior of Cu-Cr-Zr alloy was investigated by examining the evolution of worn surface morphology and subsurface microstructure. The microhardness (H) and reduced elastic modulus (E-r) of the subsurface below the worn surface measured by nanoindentation were calculated to gage the tribological performance of Cu-Cr-Zr alloy. Results show that the continuously extruded and subsequently peak-aged specimen has the best wear resistance, which indicates that the tribological properties of Cu-Cr-Zr alloy strongly depend on its strength and hardness. It can be concluded that the CEF and subsequent aging treatment process provides a new and high-efficiency procedure for the continuous preparation of Cu-Cr-Zr alloys. (C) 2021 Published by Elsevier Ltd on behalf of Chinese Society for Metals.
10.1016-j.jmst.2022.04.024	10	composites; nanoparticles; strength; matrix; high; strengthening; particles; conductivity; composite; electrical; mpa; sintering; ods; grains; mechanical	A superiority in interfacial bonding is favorable to fabricate high-strength conductive composites for electrical contact applications. In the present work, high strength and high conductivity multi-scale metallic glass composites (including micron-scale CuZrAl metallic glass reinforcement, hundred-nanometer-scale CuCrZr crystalline grain matrix, and nano-scale precipitated phase) were fabricated by a one-step spark plasma sintering (SPS). The strength and conductivity of the bulk copper matrix metallic glass composites (BCMGCs) were enhanced simultaneously with the increase in the sintering pressure of the SPS. The excellent performance is attributed to the improved interfacial bonding between the metallic glass reinforcement and the copper alloy matrix due to the high pressure assisted by temperature and pulsed current. In particular, the precipitation of nanoprecipitates at the interface further reduces the interfacial resistance and improves the mechanical properties of the composites. This work broadens the horizon for the selection and optimization of reinforcements and manufacturing processes for high-performance electrical contact materials (ECMs). (c) 2022 Published by Elsevier Ltd on behalf of The editorial office of Journal of Materials Science & Technology.
10.1016-j.jmst.2022.06.007	-1		Liquid-liquid phase separation, and the resulted solute segregation, during conventional solidification have been a long-term challenge to produce copper (Cu)-iron (Fe) immiscible composites with high strength and high conductivity. The present work reports an effective solution to this issue through laser powder bed fusion (L-PBF) in-situ alloying of Cu-8 wt% Fe. Microstructure observation showed that the fast cooling within micron-scale melt pools fully eliminated the Fe segregation and therefore the L-PBF fabricated nanocomposite achieved the homogeneous microstructure, which featured equiaxed fine grains around 1 mu m in size. Ageing of the nanocomposite at 600 degrees C for 1 h enabled precipitation of two types of nanoparticles. One is coarser Fe nanoprecipitates with body-centered cubic (BCC) structure and diam-eter of 10 0-30 0 nm, mainly distributing along grain boundaries. The other is smaller Fe nanoprecipitates with face-centered cubic (FCC) structure and diameter of 10-35 nm, being observed within the grains and having coherent interfaces with the Cu matrix. As a result, the aged Cu-Fe nanocomposite achieved tensile strength of 462.9 +/- 6.6 MPa with 30.4% +/- 1.7% elongation to failure and 74.5% IACS (International Annealed Copper Standard) electrical conductivity. The formation mechanisms of the nanoprecipitates and the strengthening mechanisms of the nanocomposite are discussed. (c) 2022 Published by Elsevier Ltd on behalf of The editorial office of Journal of Materials Science & Technology.
10.1016-j.jmst.2022.07.003	-1		In this work, pure Cu with excellent strength and ductility (UTS of 271 MPa, elongation to fracture of 43.5%, uniform elongation of 30%) was prepared using cold spray additive manufacturing (CSAM), real-izing a breakthrough in the field. An in-depth investigation was conducted to reveal the microstructure evolution, strengthening and ductilization mechanisms of the CSAM Cu, as well as the single splats. The results show that the CSAM Cu possesses a unique heterogeneous microstructure with a bimodal grain structure and extensive infinitely circulating ring-mounted distribution of twinning. Based on the single splat observation, the entire copper particle forms a gradient nano-grained (GNG) structure after high-speed impact deposition. The GNG-structured single splat serves as a unit to build the heterogeneous microstructure with bimodal grain distribution during the successive deposition in CSAM. The results also show that CSAM can achieve synergistic strengthening and ductilization by controlling the grain refine-ment and dislocation density. This work provides potential for CSAM technique in manufacturing various metallic parts with the desired combination of high strength and good ductility without additional post -treatments. (c) 2022 Published by Elsevier Ltd on behalf of The editorial office of Journal of Materials Science & Technology.
10.1016-j.jmst.2023.01.026	-1		Grain refinement into nanoscale significantly enhances the strength and hardness of metallic materials but generally reduces the thermal stability by the introduced strong tendency for grain boundary (GB) migration. Stabilizing nanograins through GB relaxation had been proven as an effective way in several metals recently when the grain size is below a critical value. Here, we discovered that the abnormally enhanced thermal stability induced by GB relaxation can be realized in 0.5% Sb or Fe doped Cu, similar to that in pure Cu. The observed critical grain sizes for GB relaxation in the two Cu alloys are almost the same as pure Cu. However, the GB relaxation effect on thermal stability is kind of suppressed compared to pure Cu with similar grain sizes because of the segregation/precipitation of Sb/Fe during the annealing process, which accelerates the detwinning and the failure of relaxed GBs.& COPY; 2023 Published by Elsevier Ltd on behalf of The editorial office of Journal of Materials Science & Technology.
10.1016-j.jmst.2023.04.012	-1		Ti additions in Cu-Cr-Zr alloys are useful for achieving high mechanical properties. In this work, the influence of Ti contents (0.25 wt%, 0.6 wt%, and 1.02 wt%) on the microstructure, mechanical, and elec-trical properties of Cu-Cr-Zr alloys has been investigated experimentally, along with thermodynamic and kinetic calculations. The electrical conductivity decreased but the hardness/strength increased with in-creasing Ti content. The lower electrical conductivity is due to increased electron scattering through the solution of more Ti atoms in the Cu matrix. As for the higher hardness/strength, it is mainly owing to higher dislocation density and finer FCC-Cr precipitates. Furthermore, a model considering the size dis-tributions of precipitates is adopted to calculate precipitation strengthening quantitatively. The calculated yield strengths are consistent with the experimental ones for the alloys. The thermodynamic and kinetic calculations reveal that increasing Ti content can facilitate the nucleation of FCC-Cr but enhance its ac-tivation energy, hence hindering the growth process. The present work study can provide an effective strategy for producing copper alloys with expected performance.& COPY; 2023 Published by Elsevier Ltd on behalf of The editorial office of Journal of Materials Science & Technology.
10.1016-j.jmst.2023.05.032	-1		Introducing the unique advantage of additive manufacturing technology into copper-based shape memory alloys (SMAs) to fabricate high-performance alloys has garnered great attention in recent years, but the intrinsic relationships between microstructure and mechanical properties need to be further clarified. In this paper, the microstructural evolution of ternary CuAlNi SMAs fabricated by laser powder bed fusion (LPBF) under the tensile-compressive loading was investigated to determine the underlying mechanism of tension-compression asymmetry, that is, excellent compressive but poor tensile properties. Multiscale characterization of the different deformation stages revealed the numerous activated deformation mechanism on the 18R martensite matrix. A twin-related transformation dominated the main plastic deformation process due to lower stacking faults energy and high-density pre-existing planer defects in the CuAlNi SMAs. Deformation twinning nucleated at prior austenite boundaries and developed into parallel and network structures inside the parent grain of different sizes. In addition, the preferred orientation in different stages, the stress-induced & gamma; phase transformation, and the interaction between dislocations and stacking faults are discussed. These results not only provide significant insights to understand the detwinning and deformation twinning process of SMAs but also establish the essential framework of microstructure and mechanical properties of Cu-based SMAs fabricated by LPBF.& COPY; 2023 Published by Elsevier Ltd on behalf of The editorial office of Journal of Materials Science & Technology.
10.1016-j.jmst.2023.06.056	-1		Dispersion-strengthened copper alloys can achieve ultra-high strength, but usually at the expense of ductility. In this study, a strategy for overcoming strength-ductility tradeoff of Cu alloys is realized through the introduction of bimodal grains structures. Cu-Ta alloys with only 0.5 at% Ta content were successfully prepared by mechanical alloying combined with spark plasm sintering. The samples prepared by one-step and two-step ball milling methods are named as Cu-Ta (I) and Cu-Ta (II), respectively. The microstructural characterizations revealed that ultra-fine equiaxed grains with uniformly dispersed Ta precipitates were obtained in the Cu-Ta alloys. High strength of 377 MPa for yield strength together with elongation of & SIM;8% was obtained in Cu-Ta (I). Bimodal grains structures composed of fine-grain zones and coarse-grain zones were successfully introduced into Cu-Ta (II) by a two-step ball milling approach, and both yield strength (463 MPa) and elongation (& SIM;15%) were significantly synergistic enhanced. The hardness values of both Cu-Ta (I) and Cu-Ta (II) were almost kept nearly constant with the increase of annealing time, and the softening temperatures of Cu-Ta (I) and Cu-Ta (II) are 1018 and 1013 & DEG;C, reaching 93.9% and 93.5% T-m of pure Cu (1083 & DEG;C), respectively. It reveals that the Cu-0.5 at% Ta alloys exhibit excellent thermal stability and exceptional softening resistance. Ta nanoclusters with semi-coherent structures play an essential role in enhancing the strength and microstructural stability of alloys. Bimodal structures are beneficial to the activation of back stress strengthening and the initiation and propagation of microcracks, thus obtaining the extraordinary combination of strength and elongation. This study provides a new way to fabricate dispersion-strengthened Cu alloys with high strength, high elongation, excellent thermal stability and softening resistance, which have potential application value in the field of the future fusion reactor.
10.1016-j.jmst.2023.08.069	-1		Producing ultrafine-grained (UFG) microstructures with enhanced thermal stability is an important yet challenging route to further improve mechanical properties of structural materials. Here, a highperformance bulk UFG copper that can stabilize even at temperatures up to 750 degrees C (-0.75 T m , T m is the melting point) was fabricated by manipulating its recrystallization behavior via low alloying of Co. Addition of 1 wt%-1.5 wt% of Co can trigger quick and copious intragranular clustering of Co atoms, which offers high Zener pinning pressure and pins the grain boundaries (GBs) of freshly recrystallized ultrafine grains. Due to the fact that the subsequent growth of the coherent Co-enriched nanoclusters was slow, sufficient particles adjacent to GBs remained to inhibit the migration of GBs, giving rise to the UFG microstructure with prominently high thermal stability. This work manifests that the strategy for producing UFGs with coherent precipitates can be applied in many alloy systems such as Fe- and Cu-based, which paves the pathway for designing advanced strain-hardenable UFGs with plain compositions. (c) 2023 Published by Elsevier Ltd on behalf of The editorial office of Journal of Materials Science & Technology.
10.1016-j.jmst.2023.10.047	-1		Extended solid solution of immiscible systems, achieved by extreme processing approaches, can be transformed into nanostructured composites via phase decomposition, which are drawing great research attention for their excellent thermal stability and high strength . Here we fabricated the supersaturated solid solution of Cu-20 at%Fe, a typical immiscible alloy, in bulk state by high pressure torsion, which provides a great freedom over powders for studying the microstructure evolution and mechanical properties in the process of the phase decomposition in immiscible alloys. We found that in the Cu-Fe solid solution, spinodal decomposition of the Fe phases took place at the initial stage of annealing through volume diffusion. This process gives rise to: (1) metastable gamma -Fe particles in the Cu grains with coherent Fe/Cu interface, and (2) the more stable alpha-Fe phase at the grain boundaries. This process was accompanied by moving boundary reaction which first proceeded in the pattern of spinodal decomposition and then changed into classical nucleation-growth mode with the depletion of Fe atoms in Cu. The resultant Cu-Fe nanocomposites were jointly strengthened by the ultrafine Cu and alpha-Fe grains according to the rule of mixture, including grain boundary strengthening and the hardening of nanoscale gamma -Fe precipitates in the Cu grains. The effects of different strengthening mechanisms were scrutinized and their contributions to mechanical properties were quantitatively evaluated. This work sheds light onto the opportunity of designing and fabricating nanostructured composites via phase decomposition in immiscible systems. (c) 2024 Published by Elsevier Ltd on behalf of The editorial office of Journal of Materials Science & Technology.
10.1016-j.jmst.2023.12.042	10	composites; nanoparticles; strength; matrix; high; strengthening; particles; conductivity; composite; electrical; mpa; sintering; ods; grains; mechanical	Laser powder bed fusion (LPBF) is a promising method for manufacturing functional and structural integrated Cu-Cr-Zr components. However, the LPBF-processed Cu-Cr-Zr alloys still suffer from the strengthductility trade-off dilemma, while maintaining high conductivity. Here, LPBF-processed Cu-Cr-Zr alloy with a hierarchical structure was obtained by increasing the Cr and Zr content simultaneously. After aging treatment, the hierarchical structure was composed of melt tracks at the macroscale, coarse grains (31.9 +/- 0.1 mu m) and fine grains (5.6 +/- 0.2 mu m) at the microscale, high-density of dislocations and dual precipitates at the nanoscale. The direct aged sample exhibited an excellent combination of strength and ductility (tensile strength was enhanced to 626 +/- 1 MPa and uniform elongation of 16.2 % +/- 1.1 %), which is superior to the traditionally wrought and LPBF-processed Cu-Cr-Zr alloys reported previously. Meantime, a good electrical conductivity of 71.1 % +/- 0.3 % IACS was also achieved. In addition, the heterogeneous deformation-induced stress caused by the hierarchical structure not only led to a large increase in yield strength but also promoted tensile ductility. (c) 2024 Published by Elsevier Ltd on behalf of The editorial office of Journal of Materials Science & Technology.
10.1016-j.jmst.2024.07.039	-1		Overcoming the tradeoff between mechanical strength and electrical conductivity is a long-standing challenge in developing advanced copper alloys for industrial applications. Herein, we report a new strategy to obtain high strength and good conductivity of Cu-Ni-Si-Ca alloy by introducing and regulating the discontinuous precipitation (DP) and continuous precipitation (CP) behaviors. The DP process combined with thermomechanical treatment was exploited to expedite the precipitation kinetics, whilst the competition between DP and CP was utilized to inhibit the nucleation and growth of continuous precipitation phase (CPP). The resultant copper alloy exhibits superior comprehensive properties with a yield strength of 956 MPa, fracture strength of 989 MPa, and electrical conductivity of 34.1 % IACS. The improved electrical conductivity is attributed to the heterogeneous-nucleation dominant DP, while the high strength stems from the combination of strain hardening and precipitation strengthening of delta-Ni 2 Si and t-Ni3Si precipitates. Notably, the precipitation strengthening arises from both the dislocation passing and cutting mechanisms, with the strongly ordered DO22-type (t-Ni3Si) phase contributing approximately 202 MPa to the overall strength through the cutting mechanism. This work offers a new pathway for alloy design of high-strength and high-electrical-conductivity copper alloys, by regulating coherent ordered nanoprecipitates through DP and CP. (c) 2024 Published by Elsevier Ltd on behalf of The editorial office of Journal of Materials Science & Technology. (c) 2024 Published by Elsevier Ltd on behalf of The editorial office of Journal of Materials Science & Technology.
10.1016-j.jmst.2024.09.017	-1		Simultaneously improving the strength and electrical conductivity of conducting metallic materials is of great significance, but it still remains a key challenge as the two properties are often mutually exclusive. In this study, we demonstrate a < 111 > oriented fibrous grains with ultra-high aspect ratio strategy for breaking such a conflict in Cu wire, which relies on the distinctive spatial distribution of grain boundaries and the highly consistent hard orientation to play their respective roles in suffering loading and conducting, thereby enabling a separate optimization of both strength and electrical conductivity. Therefore, a processing route was designed, involving directional solidification followed by large drawing deformation, to successfully construct fibrous grains with an ultra-high aspect ratio in 596.7 and ultra-high < 111 > texture proportion over 97 %, which achieves Cu wire with a remarkable combination of yield strength in 482.3 MPa and electrical conductivity in 101.63 % IACS. Finally, the mechanisms for high strength and high electrical conductivity were quantitatively discussed. (c) 2025 Published by Elsevier Ltd on behalf of The editorial office of Journal of Materials Science & Technology.
10.1016-j.jmst.2024.09.039	-1		Recent studies have shown that synergistic precipitation of continuous precipitates (CPs) and discontinuous precipitates (DPs) is a promising method to simultaneously improve the strength and electrical conductivity of Cu-Ni-Si alloy. However, the complex relationship between precipitates and two-stage aging process presents a significant challenge for the optimization of process parameters. In this study, machine learning models were established based on orthogonal experiment to mine the relationship between twostage aging parameters and properties of Cu-5.3Ni-1.3Si-0.12Nb alloy with preferred formation of DPs. Two-stage aging parameters of 400 degrees C/75 min + 400 degrees C/30 min were then obtained by multi-objective optimization combined with an experimental iteration strategy, resulting in a tensile strength of 875 MPa and a conductivity of 41.43 %IACS, respectively. Such an excellent comprehensive performance of the alloy is attributed to the combined precipitation of DPs and CPs (with a total volume fraction of 5.4 % and a volume ratio of CPs to DPs of 6.7). This study could provide a new approach and insight for improving the comprehensive properties of the Cu-Ni-Si alloys. (c) 2025 Published by Elsevier Ltd on behalf of The editorial office of Journal of Materials Science & Technology.
10.1016-j.jmst.2024.10.053	-1		Cu-Cr alloys are widely applied in electronic, aerospace and nuclear industries, due to their high strength and high conductivity. However, their terrible softening resistance limits wider applications. This paper presents a novel strategy of integrating mechanism features into interpretable machine learning (ML) to develop softening-resistant Cu-Cr alloys and to understand their mechanisms. First, the mechanism features were specially designed to describe mechanisms potentially vital to softening resistance, and they were obtained through first-principles calculations. Those mechanism features that described interfacial segregation and solute diffusion exhibited significant Gini importance during feature selection. Only integrated with them, did ML models achieve great performance, accurate predictions, and successful development of Cu-0.4Cr-0.10La/Ce (wt%) alloys with excellent softening resistance. Then, the contributions of these mechanism features to the predictions were interpreted by a game theoretic approach, but unexpectedly, they were not fully consistent with interpretations that we expected from mechanism features. Finally, investigation targeted at these inconsistencies gave novel insights into softening resistance mechanisms. The Cu-Cr-La/Ce alloys' excellent softening resistance was not induced by a prevailing mechanism of La/Ce atoms segregating at phase interfaces, nor by an expected mechanism of La/Ce atoms improving the Cr atom jump energy barriers. Instead, it was caused by a unique mechanism in which La/Ce atoms competed with Cr atoms for vacancies and therefore depleted the available vacancies for the Cr atom jump. This paper demonstrates a new paradigm of developing softening-resistant Cu-Cr alloys and understanding their mechanisms via mechanism-informed interpretable ML. (c) 2025 Published by Elsevier Ltd on behalf of The editorial office of Journal of Materials Science & Technology.
10.1016-j.jmst.2024.12.031	-1		Commercial wrought high-strength Cu-Cr-Zr alloys face limited high-temperature properties due to the rapid coarsening or dissolution of Cr precipitates. Here, we report a laser powder bed fusion (LPBF) fabricated Cu-0.84Cr-0.42Zr (wt%) alloy with exceptional heat resistance after aging. Primary Cr@Cu5Zr phase (39.8 nm) with core-shell structure and a high density of heat-stable dislocations were introduced from the rapid solidification of LPBF and enabled the alloy to gain significant improvement in high-temperature properties. After aging treatment, secondary Cr and Cu51Zr14 phases (3.4 nm) were precipitated, in which Zr solute was segregated at one side of the Cr phase, enhancing the thermal stability of Cr phase. The excellent combinations of strength and thermal conductivity were achieved at or above 400 degrees C. Particularly at 600 degrees C, the aged sample not only exhibited a high tensile strength of 196 MPa, which significantly surpassed that of wrought Cu-Cr-Zr alloys, but also possessed a thermal conductivity of 349 W/(m K) comparable to that of pure copper. (c) 2025 Published by Elsevier Ltd on behalf of The editorial office of Journal of Materials Science & Technology.
10.1016-j.jmst.2024.12.087	14	strength; properties; conductivity; electrical; mechanical; cu-; grain; mpa; electrical conductivity; aging; precipitation; phase; mechanical properties; tensile; phases	Copper materials have emerged as the preferred choice for marine heat exchangers owing to their exceptional thermal conductivity. The enhancement of surface performance can be significantly achieved by engineering micro-nano structures on the material's surface, thereby attaining improved corrosion resistance and antibacterial properties in complex marine environments. In this study, we directly fabricated a copper nanopillar array structure on the substrate via template-assisted electrodeposition. Subsequently, passivation of the pillar-structured copper surface was achieved through a formate & dodecanethiolassisted solvothermal process (Cu/FA-DT). The results indicate that the nanopillar structure effectively eliminates bacteria through physical rupture upon contact, leading to an 85.47% reduction in P. aeruginosa adhesion compared to untreated samples after 72 h of immersion in seawater. Furthermore, corrosion resistance is significantly enhanced, with inhibition rates of approximately 95.27% and 90.50% in natural and P. aeruginosa containing seawater, respectively. Notably, the thermal conductivity of copper is well preserved, ensuring its functional integrity in marine heat exchange environments. After 7 days of immersion in natural and P. aeruginosa containing seawater, the thermal conductivity of Cu/FA-DT decreased by only 15.41% and 2.78%, respectively, demonstrating superior thermal conductivity retention compared to untreated bare copper. This study provides valuable insights into the potential application of traditional copper in marine heat exchange environments. (c) 2025 Published by Elsevier Ltd on behalf of The editorial office of Journal of Materials Science & Technology.
10.1016-j.jmst.2025.01.053	-1		Ag-Cu alloys are extensively used in sliding electric contacts due to their superior electrical conductivity, but their limited wear resistance reduces component longevity. Surface severe plastic deformation (SSPD) has emerged as a promising method to enhance wear resistance and reduce friction of metals without altering the matrix composition. In this study, an Ag-20 wt%Cu alloy was subjected to SSPD for various durations, with the aim of improving tribological performance. The microstructure, hardness, and current-carrying tribological performance under different currents were systematically investigated, along with an exploration of the underlying mechanisms. The results show that in addition to introducing a high density of dislocations on the surface, SSPD also encourages the formation of (111) texture, and particularly disperses the initially long strips of Cu-rich phase into short strips and fine particles. It promotes a tribo-film composed primarily of a mixture of Cu2O and CuO that forms on the worn surface of the surface-treated sample under the 1 A current, thus significantly reducing the friction coefficient and electrical noise. Under the 10 A current, the sample treated for 60 min possesses the optimal friction coefficient (0.429), wear rate (0.791 x 10-6 mm3/(N m)), and electrical noise (0.240 V). In contrast to the Ag/Cu layered structure observed on the worn subsurface of the untreated sample, a single-phase Ag (Cu) solid solution forms on the worn subsurface of the 60-min treated sample, which improves the current-carrying tribological performance. This work provides valuable insights for the development and application of electrical contact alloys with excellent performance. (c) 2025 Published by Elsevier Ltd on behalf of The editorial office of Journal of Materials Science & Technology.
10.1016-j.jmst.2025.01.073	14	strength; properties; conductivity; electrical; mechanical; cu-; grain; mpa; electrical conductivity; aging; precipitation; phase; mechanical properties; tensile; phases	High-performance copper alloys with enhanced strength, conductivity, and toughness are critical in industrial applications, yet achieving this combination of properties in a bulk form remains challenging, as many strength-enhancing grain refinement methods are limited to small-scale production. This study investigates the development of Cu-Ni-Be alloys with high strength, high conductivity, and excellent ductility using rotary swaging (RS) as the primary processing method, followed by aging treatments. The RS process, known for its advantages in industrial-scale applications, enables the formation of fibrous, elongated grains with strong axial alignment, resulting in improved conductivity along the wire direction. Additionally, the triaxial compressive stresses inherent in RS promote effective dislocation accumulation, producing an alloy with a strength of 706 MPa, uniform elongation of 1.4 %, and conductivity of 35 % international annealed copper standard (IACS) in the as-swaged state. Optimized aging treatments further improve the comprehensive performance of the alloy, increasing its strength to 1064 MPa, uniform elongation to 10.4 %, and conductivity to 46 % IACS through the formation of dispersed nanoscale precipitates. These findings demonstrate that the Cu-Ni-Be alloy processed by RS and aging achieves a unique balance of tensile strength, ductility, and conductivity, making it highly suitable for industrial applications. This establishes RS as a viable approach for producing advanced Cu-Ni-Be alloys with tailored properties for the electrical and structural industries. (c) 2025 Published by Elsevier Ltd on behalf of The editorial office of Journal of Materials Science & Technology.
10.1016-j.jmst.2025.03.111	-1		Coarse grains and uncontrolled phase constituents have significant adverse effects on the mechanical properties of Cu-18Sn-0.3Ti alloy, thus restricting the preparation of Nb3Sn superconducting wires with higher critical current density. In this work, the strength-plasticity enhancement of powder sintered Cu-18Sn-0.3Ti alloy was realized through inducing static recrystallization and controlling phase transformation. The ultimate tensile strength, yield strength and elongation of the alloy were increased from 507.2 MPa, 229.4 MPa and 23.4 % to 677.0 MPa, 359.9 MPa and 38.9 %, respectively. Through first-principles calculations, molecular dynamics simulation, detailed thermodynamic assessment and kinetic analysis, delta-Cu41Sn11 and epsilon-Cu3Sn phases were determined to be harmful to the plastic deformation of alloy, and the annealing temperature of no more than 600 degrees C can reduce the volume fraction of Sn-rich phases, promote the phase transformation from delta phase to beta-Cu17Sn3 and gamma-Cu3Sn phases, and inhibit the formation of delta phase, which verified the experimental results. The phase constituent conductive to plastic deformation of alloy, fine grains and high-density annealing twins were the main reasons for the strength-plasticity enhancement of alloy. The results lay a foundation for the preparation of Nb3Sn superconducting wires and provide theoretical guidance for the strength-plasticity enhancement of other multi-component alloys. (c) 2025 Published by Elsevier Ltd on behalf of The editorial office of Journal of Materials Science & Technology.
10.1016-j.jmst.2025.04.040	14	strength; properties; conductivity; electrical; mechanical; cu-; grain; mpa; electrical conductivity; aging; precipitation; phase; mechanical properties; tensile; phases	Over-aging softening due to second-phase particle coarsening is a prevalent issue in age-hardenable copper alloys, limiting their performance optimization and high-temperature applications. We propose a dislocation-assisted heterogeneous co-precipitation strategy for high thermal stability in Cu-Cr-Hf alloys, leveraging the dislocation sensitivity of Hf phase nucleation as a key element of this approach . Through this, we explore their precipitation behavior and observe two novel co-precipitation modes. In solutiontreated alloys, asynchronous co-precipitation occurs: Hf phases nucleate at transformation-induced interfacial dislocations (TIIDs) within Cr/Cu phase boundaries after initial Cr precipitation. In deformed alloys, synchronous co-precipitation is observed, where Hf and Cr phases nucleate simultaneously at deformation-induced dislocations. The resulting composite nanoparticles formed via co-precipitation exhibit reduced interfacial energy. This inhibits nano-precipitate coarsening, dislocation annihilation, and copper matrix recrystallization, ultimately suppressing the over-aging softening of the alloy. After being processed by a single-pass solution-cold rolling-aging process, Cu-Cr-Hf alloy shows tensile strength of 597 MPa and electrical conductivity of 72 % international annealed copper standard, while maintaining high hardness after prolonged aging even at 500 degrees C, demonstrating an excellent strength-conductivity balance and high thermal stability. We envisage that this innovative mechanism of enhancing nanoparticle thermal stability through multi-precipitate co-precipitation can provide a pathway based on conventional industrial operations for optimizing advanced high-strength, high-conductivity copper alloys and promote their high-temperature service. (c) 2025 Published by Elsevier Ltd on behalf of The editorial office of Journal of Materials Science & Technology.
10.1016-j.jmst.2025.05.076	-1		High strength and conductivity (HSC) copper alloys with excellent high-temperature softening resistance are critical for applications such as high-power electrical connectors and controlled nuclear fusion. In this study, a Cu-1.0Cr-0.4Zn-0.1Zr-0.05Si alloy with an initial heterogeneous structure was prepared by an intensive plastic deformation (IPD) method (solution treatment followed by rotary swaging and aging). The IPD-prepared Cu-Cr-Zn-Zr-Si alloy exhibited a softening temperature of 640 degrees C, outperforming existing HSC copper alloys. To investigate the effect of the initial deformation structure on the resistance to softening, in-situ high-temperature electron backscatter diffraction was used to observe the recrystallization behavior. The initial multi-oriented heterogeneous fibrous structure was formed by alternating <111>//LD and <100>//LD deformation bands, which induced an uneven stored energy distribution and led to partial recrystallization. Johnson-Mehl-Avrami-Kolmogorov (JMAK) kinetic analysis indicated that this structural feature significantly reduced the softening rate in the later stages of recrystallization. Furthermore, IPD facilitated the transformation of <111>//LD deformation bands into <100>//LD recrystallized grains through annealing twinning, revealing a novel recrystallization mechanism contrary to conventional theories. Molecular dynamics (MD) simulations confirmed that this orientation transformation further promoted the recrystallized grain boundary migration. This study provides novel experimental evidence and theoretical insights into improving the high-temperature softening resistance through deformation structure design. (c) 2025 Published by Elsevier Ltd on behalf of The editorial office of Journal of Materials Science & Technology.
10.1016-j.jnoncrysol.2003.12.011	-1		We have investigated the magnetic susceptibility and the electrical resistivity of a new P-type icosahedral quasicrystal Cu48.2Ga33.8Mg3Sc15 and a cubic phase Cu49Ga36Sc15, interpreted as a 1/1 approximant crystal of the quasicrystal. The magnetic susceptibility of the Cu48.2Ga33.8Mg3Sc15 quasicrystal showed an increase from -3.51 x 10(-4) to -2.78 x 10(-4) m(3) kg(-1) with a rise in temperature from 120 to 300 K. The Cu49Ga36Sc15 cubic phase showed also a rise from -6.18 x 10(-4) to -4.50 x 10(-4) m(3) kg(-1) between 100 and 300 K. The increase in the susceptibility was accounted for by the temperature dependence of the Pauli paramagnetism. The experimental results strongly suggest the existence of a pseudogap in the electronic density of states at Fermi energy for the Cu48.2Ga33.8Mg3Sc15 quasicrystal and the Cu49Ga36Sc15 approximant, which has been observed in various stable icosahedral quasicrystals. The electrical resistivity of the Cu47.1Ga32.9Mg5Sc15 quasicrystal showed a negative temperature coefficient in the temperature region between 2 and 270 K. The Cu49Ga33.8Sc15.2 cubic phase showed a positive temperature coefficient in the temperature region. The tendency of the quasicrystal was qualitatively accounted for by the weak localization theory.
10.1016-j.jnoncrysol.2004.09.008	-1		The abrasive wear behaviors of three copper based bulk metallic glasses have been studied using pin-on-disc measurement and compared with both annealed metallic glass and 304 stainless steel. The volume loss increases linearly with sliding distance. However, the wear resistances of metallic glasses are not directly proportional to hardness and do not follow the wear law. The wear resistance increases in the order: annealed metallic glass, metallic glass and 304 stainless steel. The wear rates of metallic glasses are strongly dependent on the applied load. Worn surface shows that the metallic glasses suffer from severe wear compared with that of 304 stainless steel.
10.1016-j.jnoncrysol.2005.02.019	11	glass; bulk; metallic; bulk metallic; gfa; bmg; glassy; metallic glass; ability; bulk metallic glass; amorphous; addition; crystallization; mm; glass-forming	The effect of Nb substitution for Zr on the glass forming ability (GFA) and mechanical properties of Cu47Ti33Zr11-xNbxNi8Si1 (x = 0, 2,4,6,8, 11) alloys have been investigated using differential scanning calorimetry (DSC), X-ray diffractometry (XRD), high resolution transmission electron microscope (HRTEM), and atom probe field ion microscope (APFIM). Partial substitution of Zr by Nb in Cu47Ti33Zr11Ni8Si1 promotes the GFA, Cu47Ti33Zr11-xNbxNi8Si1 (x = 2,4) bulk metallic glasses (BMGs) with diameter of 5 mm can be fabricated by Cu-mold injection casting method. The plastic elongation of similar to 4.2% in Cu47Ti33Zr7Nb4Ni8Si1 BMG, when compared with similar to 1.5% in Cu47Ti33Zr11Ni8Si1 BMG, demonstrates that small amount of Nb addition can have a dramatic effect on plasticity enhancement in Cu-Ti-Zr-Ni-Si BMG. HRTEM and APFIM results show that the as-cast Cu47Ti33Zr7Nb4Ni8Si1 BMG exhibits a fully amorphous structure without nm-scale compositional fluctuation, indicating that the plasticity of the BMGs can be improved even though no microstructural obstacles hindering or branching the propagation of the shear bands are observed by HRTEM and APFIM.
10.1016-j.jnoncrysol.2006.12.021	-1		The atomic structures of liquid Cu-Ag alloys (Cu80Ag20, Cu60Ag40, Cu40Ag60 and Cu20Ag80) have been investigated in the solidification process by means of X-ray diffraction. The results show that the liquid structures of Cu-Ag alloys, which are micro-homogeneous and similar with their solid state, display quite stable changes on a large-scale range indicated by the correlation radius r(c), although the short-range order structures change obviously around their liquidus (liquid-solid transformation). This is different from the results of the In30Sn70 alloy we previously reported, which shows an abrupt structure changes around its liquidus. In addition, the Gaussian peaks decomposition of the radial distribution functions (RDF(r)) was also performed to shed light on the element distribution and structure evolution in the whole solidification process especially around the liquidus.
10.1016-j.jnoncrysol.2006.12.061	9	magnetic; magnetization; magnetoresistance; temperature; superparamagnetic; annealing; gmr; field; magnetic properties; ferromagnetic; granular; samples; magnetic field; melt-spun; particles	In this work, we study the granular samples of mixed Cu-50(Fe69Si10B16C5)(50) Composition where half of alloy composition is commonly used amorphous soft magnetic material and the other half-Cu. Glass covered Cu-50(Fe69Si10B16C5)(50) microwires were produced and their magnetic properties were studied. The evolution of the structure after the annealing was observed using X-ray diffraction with Cu K. radiation. The as-prepared Cu-50(Fe69Si10B16C5)(50) microwires present a relatively low coercivity of about 5 Oe and exhibit non-regular hysteresis loop typical behavior for two-phases systems. Annealing resulted in magnetic hardening of the samples with coercivity of about 50 Oe. The variation of the coercivity and remanent magnetization with the temperature at 5-300 K were obtained from those curves. Temperature dependence of magnetization at 5-300 K exhibits significant difference between field-cooled and zero-field cooled behaviour. Observed dependences interpreted in terms of two-phase structure of as-prepared samples and evolution of the structure under annealing.
10.1016-j.jnoncrysol.2006.12.068	11	glass; bulk; metallic; bulk metallic; gfa; bmg; glassy; metallic glass; ability; bulk metallic glass; amorphous; addition; crystallization; mm; glass-forming	The glass forming ability (GFA), nanohardness H-n, and Young's modulus E of ternary alloys in the compositional series Cu60Hf40-x- Ti-x (x = 5-35) are reported and discussed. Bulk glass formation was observed for the three alloys x = 17.5, 20 and 22.5, with critical rod diameters d(c) for a fully glassy structure of 4, 4 and 3 mm, respectively. A d(c) of 4 mm was also observed for the Cu55Hf25Ti20 alloy. These compositions generally had the highest values of reduced glass temperature while no correlation was observed between the GFA and the parameter Delta T-x. Both H-n and E surprisingly showed minima at similar to 20 at%Ti for the Cu60Hf40-xTix series. The addition of 1 at%B or Y to Cu60Hf22.5Ti17.5 alloy slightly decreased the GFA but slightly increased the elastic modulus.
10.1016-j.jnoncrysol.2007.05.119	11	glass; bulk; metallic; bulk metallic; gfa; bmg; glassy; metallic glass; ability; bulk metallic glass; amorphous; addition; crystallization; mm; glass-forming	Amorphous CU50-xZr(45)Al(5)Nb(x), (x = 0, 1, 3 and 5 at%) samples with critical diameters of 1.54-2.05 mm were formed by copper-mold suction casting. The effects of Nb on the glass formation ability were evaluated with differential scanning calorimetry and the corrosion resistances of the alloys with the addition of Nb were evaluated in 1 N HCl, 3% NaCl and 0.5 N H2SO4 solutions, respectively, by weight loss and polarization curve measurements. The samples surfaces were examined after the corrosion test with SEM. It was found that the addition of Nb causes a decrease of AT, Of Cu50-xZr45Al5Nbx alloy from 54 K to 45 K. On the other hand, the corrosion resistances in various solutions were improved with the addition of Nb.
10.1016-j.jnoncrysol.2008.05.082	11	glass; bulk; metallic; bulk metallic; gfa; bmg; glassy; metallic glass; ability; bulk metallic glass; amorphous; addition; crystallization; mm; glass-forming	The effects of the gradual substitution of Zr by Hf on glass formability and thermal stability in the Cu45Zr45-xHfxAg10 alloys and the effects of small additions of Si on glass formability in the Cu45Zr45Ag10 alloy are reported and discussed. The samples were prepared as ribbons of thickness in the range 25-200 mu m by melt spinning and as conical bulk shapes, with a length of 50 mm and cone base diameters in the range 2-10 mm, by suction die casting. The alloy Cu45Zr45Ag10 had a critical cylindrical rod diameter for glass formation, d(c), of 3.5 mm but substitution of 1.5 and 3.5 at% Zr by Hf resulted in substantial increases to 5.5 and 4.5 mm, respectively. However, for x in the range 5-40 at%, d(c) was reduced to <1 mm. The small addition of Si proved to be beneficial to the glass forming ability (GFA), increasing d(c) up to 5.5 mm for 0.5 at% Si. Thus the chemical and atomic size similarities of Hf and Zr do not guarantee that bulk glass formation will be maintained on substituting large proportions of Zr by Hf though small substitutions of Hf and of minor additions of Si were beneficial to the GFA. These effects are discussed in terms of the possible influence of the alloying additions on the liquid structure and on the number density of heterogeneous nucleants.
10.1016-j.jnoncrysol.2010.02.004	11	glass; bulk; metallic; bulk metallic; gfa; bmg; glassy; metallic glass; ability; bulk metallic glass; amorphous; addition; crystallization; mm; glass-forming	Bulk amorphous alloys (Cu47Ti34Zr11Ni8)(99)M (M = Al, Be, Si, Nb, Fe and Co) were prepared by arc melting and suction casting. The effect of the addition of alloying elements on the glass-forming ability and thermal stability of Cu47Ti34Zr11Ni8 was studied. With the addition of Si, the glass-forming ability of the Cu47Ti34Zr11Ni8 alloy is improved, which is evidenced by the increase of supercooled liquid region Delta T-x, the reduced glass transition temperature T-rg, gamma parameter, K-H stability parameter. With the addition of Al, Be, Co, Fe and Nb, the glass-forming ability of the alloys is decreased. Calculation of the formation enthalpies of amorphous alloys by using Miedema's theory, show that the glass-forming ability of the (Cu47Ti34Zr11Ni8)(99)M decreases with increasing formation enthalpy of the amorphous phase except in the case of Cu47Ti34Zr11Ni8. The glass transition activation energy linearly increases with increasing atom size parameter delta.
10.1016-j.jnoncrysol.2010.06.016	-1		In this work, the structure and crystallization of amorphous (Cu(50)Zr(50))(100-x)Al(x) (x=0, 2.5, 5, 7.5, 10) powders produced by gas atomization were studied. X-ray diffraction patterns showed an amorphous structure in the as-atomized powders; however, TEM observations revealed the presence of nanocrystals in all the samples. Differential Scanning Calorimetry (DSC) analyses revealed an improved glass forming ability (GFA) in the alloys containing Al, with the (Cu(50)Zr(50))(97.5)Al(2.5) alloy being the one with the best GFA. Kissinger analyses showed that the activation energy Ea for crystallization increased with the Al content, and the Avrami parameter, n was higher compared to traditional crystalline metallic alloys. Structural analyses of crystallized samples revealed the formation of Cu(10)Zr(7) nanocrystals.
10.1016-j.jnoncrysol.2012.09.007	-1		Local structure of Cu-20at%Sb melts has been studied by X-ray diffraction and ab initio molecular dynamics simulation. Pre-peaks in relation with medium-range order are observed in structure factor. Negative Warren-Cowley parameters reflect the existence of chemical order. With an obvious pre-peak. broadening intensities of Cu3Sb are in good agreement with experimental results, indicating structure similarity of Cu3Sb to ordered clusters in the melts. These imply that origin of pre-peaks is in relation with Cu3Sb-like clusters. Abnormally large activation energy of viscous flow and negative temperature coefficient of resistivity are well interpreted as the existence of medium-range order clusters.
10.1016-j.jnoncrysol.2012.12.030	-1		Cu-based and Zr-based bulk metallic glasses matrix/tungsten fiber composites were produced by infiltration process at different temperatures and times. A characterization based on X-ray diffraction (XRD) and scanning electron microscopy (SEM) is presented. The composites were tested in compression and hardness. The quality of bulk metallic matrix composites is not only experienced by the properties of the matrix and reinforcement but also by the controlling of the infiltration conditions, such as infiltration temperature and time. These parameters are important for wet-ability and interface reaction of the liquid with the reinforcement. It has been found that the reaction layer cannot be detected between the wires and matrix for Cu-base BMGCs; this may be an important difference between Zr-base and Cu-base BMG matrices and their deformation mechanism.
10.1016-j.jnoncrysol.2013.03.032	-1		Four-point-bend fatigue experiments were conducted on Cu45Zr45Ag7Al3 bulk metallic glass, which was done by the use of an electrohydraulic machine, at a frequency of 10 Hz (using a sinusoidal waveform) with an R ratio of 0.1, where R = sigma(min)/sigma(max) (sigma(min) and sigma(max) are the applied minimum and maximum stresses, respectively). This material shows a fatigue-endurance limit and fatigue ratio of 386 +/- 5 MPa and 0.26 +/- 0.01, respectively, and the fracture toughness is estimated to be about 23-30 MPa-m(1/2). The fatigue-fracture morphology indicated that Cu45Zr45Ag7Al3 has a significantly brittle fracture mode. The fracture surface can be divided into four regions: crack initiation, crack propagation, fast fracture, and melting regions. The fracture mechanism is discussed.
10.1016-j.jnoncrysol.2013.07.007	2	corrosion; surface; film; electrochemical; films; spectroscopy; layer; current; solution; potential; resistance; composition; x-ray; ions; showed	In this study, corrosion behavior of Cu60Zr20Ti20 (at. %) metallic glass is investigated in acidic and neutral chloride solutions, at varying molar concentrations of chloride and also in alkaline solutions. Further, to investigate Cu60Zr20Ti20 glassy ribbon in biological conditions, it is evaluated in phosphate buffered saline (PBS) solution. Results indicate that corrosion resistance decreases with increase in chloride concentration in case of acidic and neutral solutions. While in case of alkaline solution, corrosion resistance is found to increase with increase in pH of solution. The glassy alloy has exhibited excellent corrosion resistance in PBS medium. In order to understand the corrosion behavior, the surfaces of the samples were studied using scanning electron microscopy (SEM). SEM examination reveals pitting type of corrosion. The possible reasons for pitting corrosion in metallic glasses have been addressed in the present study.
10.1016-j.jnoncrysol.2013.07.023	-1		The structural and thermal sensitivity of Cu(60-x)Zr(30 + x)Ti10 (x = 0, 5, and 10 at%) amorphous alloys to pressure was investigated. The structural sensitivity to pressure decreases with increasing Cu content, resulting in the decrease of the deforming and casting capacities. The increase of the crystallization enthalpy is positively related with the increase of the free volume. The activation energies for the glass transition (E-g) and the crystallization (E-x) increase with increasing Cu content for the as-cast and compressed amorphous alloys, but decrease after the compression. The more the Cu content or the increment of the free volume is, the more the decrement of the E-g. Thus the increase of the free volume significantly influences the glass transition and the crystallization. Moreover, the effect of the pressure on the glass transition depends stronger on the change of the free volume than on the magnitude of the free volume.
10.1016-j.jnoncrysol.2013.08.030	11	glass; bulk; metallic; bulk metallic; gfa; bmg; glassy; metallic glass; ability; bulk metallic glass; amorphous; addition; crystallization; mm; glass-forming	The Cu47.5Zr47.5Al5 bulk metallic glass (BMG) and its composites have been synthesized by the copper-mold suction casting method and proper annealing treatment. The corrosion behaviors in seawater solution and mechanical properties of the BMG and its composites have been investigated by electrochemical polarization measurement, scanning electron microscopy and MTS Criterion testing machine. The results show that the as-cast BMG composite exhibits the higher corrosion poteptial and lower corrosion current density as well as distintt passive region. Combined with the corrosion morphologies, it suggests that the as-cast BMG composite has a higher corrosion resistance in seawater than the BMG and as-annealed composite, which is attributed to an appropriate amount of CuZr nanocrystals dispersing homogeneously in the glassy matrix. Compared to its composites, the Cu-based BMG with fully amorphous structure exhibits good ductility of-l% plastic elongation and high compressive fracture strength of -1843 MPa.
10.1016-j.jnoncrysol.2013.10.010	-1		The microstructure evolution during mechanical milling was studied in the CuZrAl system. The compositions lay on the two liquidus surfaces indicating different solidification processes in the three alloys. Cu(55-x)Zr(35 + x)Al10 (x = 0; 5; 10 at%) master alloys were produced by arc melting. After identification of the phases, the master alloys were milled for 25 h and amorphous/crystalline powders were synthesized. The master alloys contained Al21Cu28Zr51, AlCu2Zr, CuZr and traces of Cu10Zr7 phases in different volume fractions. The optimal milling time was determined to be 15 h based on the results of X-ray diffractometry (XRD) and differential scanning calorimetry (DSC) examinations. The 5 h milled powder contained CuZr and Al21Cu28Zr51 phases, which diminished due to further milling resulting in amorphous matrix composite with nanosized Al21Cu28Zr51 phase. The thermal stability of the samples was investigated by DSC. The peak temperatures of the first crystallization process of the as-milled powders shifted as function of milling time and polynomial curves were fitted to the measured points. .
10.1016-j.jnoncrysol.2014.07.035	-1		The local structure and atomic packing in CuxZr100-x (46 <= x <= 70) alloys have been investigated using classical molecular dynamics. We convincingly demonstrate that the atomic packing efficiency of the polytetrahedral clusters strongly correlates with the glass-forming ability. It is found that the full-icosahedra (< 0,0,12,0 >), which is considered to be a key local structural feature associated with the glass formation in metallic alloys, alone cannot explain the compositional dependence of glass-forming ability. We suggest that the population of the so-called defected icosahedra (< 0,2,8,2 >), apart from the full-icosahedra, could be crucial to account for the observed high atomic packing efficiency in the best glass-forming compositions.
10.1016-j.jnoncrysol.2015.01.010	-1		While X-ray scattering studies can provide some insight into the average topological structure of liquids, they provide limited information on chemical ordering. Combined X-ray and neutron scattering studies can address this limitation, but are often difficult, time consuming and expensive, if isotopes are used for the neutron scattering measurements. Further, it is extremely difficult to make neutron scattering studies of reactive liquids like the Zr-based alloys of interest as metallic glass formers, particularly in the supercooled state. Here, a method for obtaining some chemical information that was applied previously to Cu-Zr glasses is used to obtain estimates of the partial pair correlation functions of their liquids. X-ray scattering data from Cu-Zr liquids with a range of chemical combinations are combined with molecular dynamics study results for one composition to consistently construct the partial pair correlations. The total pair correlation functions calculated using these partials agree well with the experimental data.
10.1016-j.jnoncrysol.2016.03.016	-1		Upon nanoindentation, the rate-jump method and creep test were conducted on Cu-Zr-Al metallic glassy films with thickness of 500 nm, 900 nm and 1500 nm. Based on the strain rate sensitivities (SRS) estimated by the two methods, the shear transformation zone (STZ) volumes of all the samples could be determined, respectively. Both experiment results show STZ volume increases with the film thickness increasing. In addition, substrate effect was carefully excluded on the present measurements. The variation trend of STZ volume was discussed in terms of free volume content, which was thought to be concerned with the sputtering process.
10.1016-j.jnoncrysol.2016.09.015	11	glass; bulk; metallic; bulk metallic; gfa; bmg; glassy; metallic glass; ability; bulk metallic glass; amorphous; addition; crystallization; mm; glass-forming	Change in melt structure of Cu64Zr36 binary metallic glass (MG) was studied using resistivity and differential thermal analysis in continuous heating process, abnormal structural changes were observed with temperature elevating. Cu64Zr36 MG ribbons with different melt temperatures were prepared using single roller spinning method, experimental results based on resistivity, DSC, and XRD indicate that the thermal stability and glass forming ability (GFA) of Cu64Zr36 MGs are greatly affected by the melt temperature. With the increasing of the melt temperature, the crystallization temperature (T-x) and supercooled liquid region (Delta T-x) shift from 780.7 K and 41.9 K of the MG with the lowest melt temperature of 1353 K towards to 800.3 K and 48.1 K of the MG with the highest melt temperature of 1653.K. The relationship of the melt temperature and GFA was further studied by injecting the melt into a cone-shape copper mould. The critical diameter can reach Phi 2.5 mm of the Cu64Zr36 MG with the highest melt temperature of 1653 K. However, the Phi 2.5 cross section of Cu64Zr36 MGs prepared with the melt temperature lower than 1653 K shows apparent Bragg peaks.
10.1016-j.jnoncrysol.2016.12.016	-1		Melt-spun Cu64.5Zr35.5 metallic glass ribbons were subject to 250 degrees C annealing for 0.5 to 2 h without leading to crystallization. Both the as-spun ribbon and the annealed ribbon were then reserved at room temperature and aged for one month, during which all samples became crystallized and oxidized on the surface. The surface of the aged ribbons tuned into brassy yellow and was featured an unchanged amorphous area and a nano-crystalline area fully decorated with crystallization and oxidation products. The two areas responded differently to the following dealloying process carried out in 0.025 M HF. The amorphous area were turned into nanoporous structure, but the dealloyed nano-crystalline area showed more complex morphology, which was composed of micron -sized Cu20 crystals rooted in the nanoporous structure.
10.1016-j.jnoncrysol.2016.12.017	11	glass; bulk; metallic; bulk metallic; gfa; bmg; glassy; metallic glass; ability; bulk metallic glass; amorphous; addition; crystallization; mm; glass-forming	The aim of this study was to evaluate new Zr-based bulk metallic composites with crystallized dendrites or droplets which have the volume fraction below the critical one (the percolation limit). The Cu36Zr48A18Ag8 alloy was chosen as matrix. Dendrites formed by in-situ solidification due to Ni addition. It was found that a new monotectic alloy system can be created successfully owing to Y addition (1-7 at%) to the matrix. Small amount of dendrites with non-random distribution has a strong influence on the compressive strength . Experiment showed that the alloy with 4.1 at% Ni has the maximum compressive strength (1998 MPa) and Young's modulus (86 GPa) within the examined samples. The results of compression test reveal that the cracks propagate near the small droplets below 1 mu m in diameter which generate weakening in the microstructure. In contrast, the large droplets especially above 3 pm in diameter create a strong barrier for the shear band propagation.
10.1016-j.jnoncrysol.2017.03.037	-1		Berkovich nanoindentation experiments have been performed on amorphous /nanocrystalline nanolaminates with individual Cu-Zr-Al layers (45 nm, 90 nm, 225 nm) and Cu layers (7.5 nm & 15 nm). Elastic modulus, hardness and indentation morphology were detected and compared to those of single Cu-Zr-Al thin film. Creep deformation was systematically investigated at various holding depths and loading rates. For the sample with thinner amorphous layer, a more pronounced creep deformation was observed and it was confirmed to be due to the size effect of Cu-Zr-Al layers and the addition of Cu layers. The creep deformation was identified to be history-independent through applying various loading rates. The strain rate sensitivities were calculated from the steady-state creep and a sharp enlargement appeared as the amorphous layer reduced down to 90 nm, implying a transition of creep mechanism in nanolaminates.
10.1016-j.jnoncrysol.2017.04.040	-1		The notch toughness of wear-resistant Cu43Zr43Al7Be7 bulk metallic glasses (BMGs) with in-situ crystallization is investigated. Using different cooling rates during copper mold casting and a post-cast anneal, the amount of crystallization is controlled and varied. The notch toughness correlates most closely with the composition of the remaining amorphous matrix, as measured by energy-dispersive X-ray spectroscopy (EDS). As the matrix composition shifts further away from the designed high-glass forming composition, the toughness decreases. The sample with a matrix composition that closely matches Cu43Zr43Al7Be7 is shown to be the toughest, with a notch toughness of 54 MPa-m(1/2). X-ray diffraction (XRD), EDS and electron backscatter diffraction (EBSD) were used to identify the metastable crystalline phase as Cu3Zr5Al2(+Be) with a cubic Fm (3) over barm structure. Furthermore, the crystalline phases are shown to be harder than the glassy matrix, and therefore likely contribute to the high wear-resistance of the studied BMG. Under standard XRD operating parameters, as used in the literature, all of the samples examined in this study appear to be fully amorphous, yet many are shown to contain a significant number of crystalline regions. In order to identify in-situ crystallization using XRD with Cu K alpha radiation, extremely long dwell times and high X-ray fluxes are required. This demonstrates the importance of reporting XRD operating parameters when trying to evaluate the amorphous nature of BMGs.
10.1016-j.jnoncrysol.2017.12.016	12	thermodynamic; ternary; phase; data; experimental; equilibria; phase equilibria; liquid; binary; experimental data; calculated; phases; literature; model; calphad	Cu-Zr based alloys have been used as metallic glass alloys owing to their high glass forming ability (GFA). Ni is added into these alloys to enhance their mechanical property and improve GFA. These Cu-Ni-Zr ternary alloys have a high potential to be used as metallic glass alloys. Herein, we investigated and assessed thermodynamically the phase equilibria of the Cu-Ni-Zr ternary system at 800 degrees C using the calculation of phase diagram (CALPHAD) method based on the experimental data. Thirty-three alloys were prepared using the arc melting method. At 800 degrees C, the isothermal section of the Cu-Ni-Zr ternary system composed of 15 single-phase regions, 20 two-phase regions, and 8 three-phase regions; no ternary intermetallic compounds were found. In addition, a continuous solid solution was formed by the Cu10Zr7 and Ni10Zr7 phases at 800 degrees C. Furthermore, the thermodynamic parameters were optimized using the phase equilibrium data. The calculated isothermal section and metallic glass region prediction of the Cu-Ni-Zr ternary system were reasonable and satisfactory compared with the literature data.
10.1016-j.jnoncrysol.2017.12.045	-1		Nanolaminates consisting of individual amorphous Cu-Zr-Al layers and nanocrystalline Cu layers on Si substrates were prepared by alternatively magnetron sputtering and hardness measurements were conducted upon nanoindentation with a standard Berkovich indenter. Indentation hardness showed a strong size effect in single Cu-Zr-Al film, its decline trend was slower in the nanolaminates with thinner amorphous layers. While experimental hardness was obviously below the expected rule-of-mixture value for all the nanolaminates. Finite element modelling (FEM) analysis was performed in each sample to explore stress distribution beneath indenter. A higher proportion of Cu layers has been involved into plastic region than the nominal value. Besides, interfacial barrier strength was estimated for each sample. The experimental results could be well described by the modified rule of mixture integrated with true ratio of Cu to Cu-Zr-Al in plastic region and the interface strengthen effect.
10.1016-j.jnoncrysol.2019.119531	13	clusters; atomic; glass; atoms; composition; dynamics; metallic; icosahedral; glasses; simulations; molecular; cu-zr; molecular dynamics; metallic glasses; structural	The thermodynamic driving force is used to obtain the initial mixing ratio of binary eutectics to design Cu-based bulk metallic glasses. By adjusting approximately 5% proportionality coefficients from the primary mixing ratios of eutectic units, we directly locate amorphous compositions with critical casting diameter of 5 mm (Cu47.5Zr45.1Al7.4) and 7 mm (Cu47.3Zr45.8Al6.4Sn0.5) in Cu-Zr-Al and Cu-Zr-Al-Sn systems, respectively. Using the Cu-Zr-Al alloys as an example, the improvement of glass-forming ability (GFA) is systematically analyzed based on thermodynamics and atomic-scale structure. A relatively lower driving force for crystallization and larger populations of Cu-centered full icosahedra with the large tendency to form MROs jointly contribute to the stability of liquid. With regard to topology, the closer local atomic size ratio compared with the ideal value for icosahedral packing around the Cu atom may be the dominant factor for the higher number of Cu-centered full icosahedra and enhanced GFA.
10.1016-j.jnoncrysol.2020.120150	11	glass; bulk; metallic; bulk metallic; gfa; bmg; glassy; metallic glass; ability; bulk metallic glass; amorphous; addition; crystallization; mm; glass-forming	To improve the fabrication efficiency of bulk metallic glasses (BMGs) with high mechanical properties and low costs, Cu47Zr45Al8 and (Cu47Zr45Al8)(98.5)Y-1.5 slabs with the cross-section of 50 x6 mm were produced by horizontal continuous casting method (HCC). It is proved that by adding Y to Cu47Zr45Al8, the crystallization behavior could be significantly decreased, and an amorphous structure was obtained when it was casted at DT = 80 K. The obtained amorphous structure was proved by XRD, TEM, DSC analysis. The glass transition behavior and crystallization were identified with T-g of 671 K, T(x)of 771 K, Delta T-x of 80 K, and Delta H-0 of 46.2 Jig, respectively. In terms of mechanical properties, the compressive strength and Vickers hardness reached 1803 MPa and 493 HV, respectively. Fracture morphology revealed that the fracture is characterized by limited rheological deformation and high localization of shear band expansion, which results in a mixed fracture mode of ductile and brittle.
10.1016-j.jnoncrysol.2020.120387	12	thermodynamic; ternary; phase; data; experimental; equilibria; phase equilibria; liquid; binary; experimental data; calculated; phases; literature; model; calphad	The Cu-Zr-Ti alloys are one of popular metallic glass systems due to their high glass-forming ability (GFA), lower cost, and good mechanical properties. The phase equilibria of the Cu-Zr-Ti ternary system are experimentally investigated first to reassess thermodynamic parameters. The isothermal section of the Cu-Zr-Ti ternary system at 703 degrees C is composed of 15 single phases including the ternary phase-Cu2TiZr, 17 two-phase regions, and 17 three-phase regions. The CuTi2-CuZr2 phases are formed as a continuous solid solution. The CuZr phase was not present in this ternary system. The calculation of phase diagram (CALPHAD) method can be used to predict the metallic-glass region. The suppressed intermetallic compounds, liquid miscibility gap, and spinodal curve were first combined to predict metallic-glass regions. The predicted region is in good agreement with the literature data and experimental results of the bulk-metallic-glass alloys applied in this study.
10.1016-j.jnoncrysol.2021.120835	-1		The prediction of glass forming ability (GFA) of alloys is of vital importance for the development of novel amorphous alloys. In this paper, the GFA of Cu-Zr-based alloys was calculated by an integrated thermodynamic parameter (PHSS), which involves the influences of mixing enthalpy (Delta HChem), mismatch entropy (S sigma) and configurational entropy (Delta Sc). Our General Solution Model (GSM) was used for the prediction of Delta HChem, which showed better consistency with experimental data than Gallego or Takeuchi model. Besides, the correlations of PHSS with Critical Diameter (Dc) was found and fitted well with experimental data. Moreover, the glass forming ranges of two types of Cu-Zr-based alloys were predicted according to PHSS, which was verified by experiment and agreed well with the experimental data available in reference and our experimental results. Therefore, the prediction of PHSS combined with GSM model is expected to provide guidelines for the design of Cu-Zr-based amorphous alloys.
10.1016-j.jnoncrysol.2021.121266	11	glass; bulk; metallic; bulk metallic; gfa; bmg; glassy; metallic glass; ability; bulk metallic glass; amorphous; addition; crystallization; mm; glass-forming	In the present study, the glass-forming ability (GFA) of (Cu50Zr43Al7)(100-)xYx (x = 0, 2, 4 and 6 at%) bulk metallic glasses (BMGs) was investigated from thermodynamic and kinetic viewpoints. The amorphous structure of the alloys was confirmed using several techniques including X-ray diffraction (XRD), high-resolution transmission electron microscopy (HRTEM), and differential scanning calorimetry (DSC). The thermal characteristics obtained through DSC and differential thermal analysis (DTA) were employed to establish a correlation between the GFA and thermodynamics/kinetics factors. The (Cu(50)Zr(43)Al(7)98)Y(2 )BMG has a promising GFA of 15 mm diameter, i.e. a 50% increase in GFA compared to the base alloy. Several GFA indicators (Delta Tx, Trg, (gamma )and K) confirm the excellent glass-forming capability of 2 at% Y-doped BMG. The role of the optimum yttrium content in improving the GFA was scrutinized considering atomic, topological, and thermodynamics concepts. The interpretations imply that Y enhances the GFA through two main ways including promoting a more densely packed atomic configuration and also through scavenging oxygen as an undesirable element in glass-forming systems.
10.1016-j.jnoncrysol.2021.121270	-1		This work focused on the effect of the structural order and dimensionality on the deformation mechanism of Cu-Ag alloy and the triggering factors of this mechanism. It is revealed that (i) the weakness of the system develops from bulk to nanoscale and crystalline to amorphous systems, (ii) Cu-Ag nanowires are more flexible than their bulk counterparts, (iii) crystalline Cu-Ag alloys are stiffer than amorphous systems. The reason for early yielding and less stiffness of amorphous Cu-Ag nanowire with respect to bulk material is the less fraction of ideal icosahedra. Cu atoms are a key factor to characterize the mechanical response of both amorphous Cu-Ag alloys. While there are two different deformation modes in crystalline systems, the only mode observed in the amorphous alloy is homogeneous deformation. The presence of (0,5,2,x) (x = 5,6) polyhedral is the reason for the transition of deformation from homogeneous to inhomogeneous in the crystalline Cu-Ag alloys.
10.1016-j.jnoncrysol.2022.121800	-1		The effects of pressure on the dynamic property and glass transition of Cu54.2Ag45.8 eutectic melt were systematically studied by extensive molecular dynamics simulations. It is shown that an increasing external pressure can slow down the dynamics of the melt and enhances the dynamic heterogeneity. As the pressure increases, the dynamic crossover temperature and glass transition temperature monotonously increase. Application of an external pressure to the melt is conducive to formation of < 0, 3, 6, 4 > and < 0, 3, 6, 3 > polyhedrons in the metallic glass, but unfavorable for formation of < 0, 0, 12, 0 > clusters. The increase of pressure results in an inverse structure-energy relationship in the relaxed glass, i.e., the potential energy increases with increasing atomic packing density, because the relaxation of local structure into the low-energy configuration is restricted. Finally, the effects of temperature and pressure on the microstructure evolution during glass formation were compared.
10.1016-j.jnoncrysol.2023.122405	-1		In this study, a new design strategy of metallic glasses is proposed using melting entropy to guide the compositions, which allows for the consideration of intermetallic compounds to serve as the starting materials. The melting entropy based strategy is verified by the detailed studies on the Cu-Zr-Hf alloys. The metallic glass design triggered by intermetallic compounds challenges the traditional cognition that the intermetallic compounds should be preferentially excluded when focusing on the glass formation compositions. This reinforces the viewpoint that low melting entropy is conducive to glass formation. The new strategy is of high targeting performance in search of starting materials to design glasses, distinct from the trial-and-error mode. This study also provides a new perspective for the understanding of glass formation mechanism.
10.1016-j.jnoncrysol.2023.122607	-1		Formation abilities and mechanical properties are essential for the application of amorphous alloys. In this work, the concept of similar elements has been expanded to similar clusters. Firstly, taking the topologically dense packed clusters Ni-Ni6Zr6 from the Ni-Zr system as the basic structural unit, a series of Cu-Ti-based alloy compositions with high formation ability are parsed and designed. The best composition is Cu46.15Ni7.69Ti32.70Zr13.46 with the cluster expression of Ni-Cu6Zr1.75Ti4.25. Then, the amorphous formation abilities are analyzed from the perspective of the packing degree of clusters and the mixing entropies. Secondly, the crystallization activation energies for characteristic temperatures deduced by Kissinger's approach are analyzed. Finally, the plasticity of Cu-Ti-based amorphous alloys is investigated and Cu46.15Ni7.69Ti32.70Zr13.46 exhibits outstanding fracture strength of 2168 MPa. The results in this paper lay the foundation for further exploration of amorphous alloys with high formation ability, good thermal stability, and high compressive plasticity.
10.1016-j.jnoncrysol.2023.122758	11	glass; bulk; metallic; bulk metallic; gfa; bmg; glassy; metallic glass; ability; bulk metallic glass; amorphous; addition; crystallization; mm; glass-forming	Three Cu-Zr-Ti plate-like amorphous alloy composite powders were prepared by ball milling the corresponding alloy powders. Their crystallization behaviors are systematically investigated by non-isothermal and isothermal modes. The phase transition during the ball milling would be Cu51Zr14 -> amorphous+Cu51Zr14 for Cu70Zr15Ti15, Cu51Zr14+Cu -> amorphous+Cu+Cu51Zr14 -> amorphous+Cu for Cu80Zr10Ti10, Cu+Cu3Ti -> amorphous+Cu for Cu90Zr5Ti5, respectively. The crystallization temperature increases according to the sequence of Cu70Zr15Ti15, Cu80Zr10Ti10 and Cu90Zr5Ti5. The crystallization phases are Cu3Ti and Cu for the isothermal crystallized Cu70Zr15Ti15, the nonisothermal and isothermal crystallized Cu80Zr10Ti10, and the nonisothermal crystallized Cu90Zr5Ti5. The crystallization phases are Cu51Zr14, Cu3Ti and Cu for the nonisothermal crystallized Cu70Zr15Ti15, while Cu for the isothermal crystallized Cu90Zr5Ti5. The detailed crystallization mechanism of nonisothermal and isothermal modes are discussed.
10.1016-j.jnoncrysol.2024.122875	-1		In this study, Cu -based amorphous composites are subjected to elastic preload and ultrasonic vibration (pre -UP) treatment at room temperature, with preloads of 250 N, 500 N, 750 N, and 1000 N and ultrasonic amplitudes of 15 mu m, 25 mu m, 34 mu m, and 50 mu m. Additionally, the mechanical response, ultrasonic transmission efficiency, microstructure evolution, and accommodation mechanism characteristics of Cu -based amorphous composites under different elastic preload and ultrasonic vibration conditions are studied. At low amplitudes/low preloads, the free volume dominates and no nanocrystals precipitate. At low amplitudes/medium preloads or at medium amplitudes/low preloads, the free volume and nanocrystals coexist as the main microstructure. At high amplitudes/high preloads, nanocrystals dominate and the free volume content decreases sharply. Increasing the amplitude and decreasing the preload can improve the ultrasonic transmission efficiency. The mechanical response is related to the ultrasonic impact effect and the ultrasonic hardening effect, which are determined by the distance between the ultrasonic punch and the upper surface of the sample. The low ultrasonic impact energy prevents atoms from crossing the energy barrier, resulting in low ultrasonic transmission efficiency. The increase in ultrasonic impact energy encourages atoms to cross the energy barrier, significantly increasing the ultrasonic transmission efficiency.
10.1016-j.jnoncrysol.2025.123731	-1		In this study, the dynamic phase transformation mechanism of a Cu-Zr based amorphous alloy under tensile loading was revealed through experimental characterization and molecular dynamics (MD) simulation. Through integration of in-situ field scanning electron microscope (SEM) observations and X-ray diffraction analyses, the structural evolution of the amorphous matrix was observed to be induced by the stress-induced phase transformation mechanism during the tension process. The body-centered cubic (BCC) phase was formed at the initial stage, followed by the nucleation of the face-centered cubic (FCC) phase in the BCC/amorphous phase at the later stage, eventually forming a multistage laminar structure composed of the superficial FCC phase, the subsuperficial BCC phase, and the amorphous phase in the core. The phase transformation process was simulated by MD, and the stress field evolution mechanism was revealed: stress shielding was exhibited by the BCC phase, while the main load was borne by the FCC phase and the amorphous phase. Local stress peaks were formed at the phase boundaries due to the mismatch of the elastic modulus at the interface. Bilinear stages were observed in the macromechanical curves: Stage I was dominated by the uniform deformation of the amorphous phase, whereas Stage II was characterized by the BCC phase bearing the plastic deformation. The synergistic regulation of the high plasticity of amorphous alloys was elucidated in this study through the multiphase competition mechanism, providing key theoretical support for the design of new metal-glass composites.
10.1016-j.jnucmat.2004.04.027	-1		Radiation-induced defect structures are known to elevate material yield strength and reduce material ductility. Together, these changes substantially reduce uniform elongation compared to the unirradiated material condition so that the small strains induce plastic instability. This process, commonly known as flow localization, is examined here for selected copper alloys and compared to similar response in 316SS. It is found that uniform elongation levels are limited by a critical material strength which is independent of the irradiation damage state. This result establishes that the details of the post-yield flow and strain hardening processes are less important than the critical stress for controlling plastic instability. In the case of OFHC Cu, post-irradiation heat treatment restores some initial ductility, but also reduces the critical stress for incipient flow localization. (C) 2004 Published by Elsevier B.V.
10.1016-j.jnucmat.2004.04.256	7	irradiation; shear; grain; ta; deformation; size; radiation; voids; nanocrystalline; simulations; similar; void; temperature; irradiated; boundaries	We present results of a large-scale atomic-level study of dislocation-precipitate interaction. We have considered a (1)/(2) <1 1 1> edge dislocation gliding in alpha-iron containing coherent copper precipitates of size from 0.7 to 6 nm over a temperature range from 0 to 450 K. The results demonstrate that some features are qualitatively consistent with earlier theoretical conclusions, e.g. the critical resolved shear stress (CRSS) is proportional to L-1 and In(D), where L and D are precipitate spacing and diameter. Other features, which are intrinsic to the atomic-level nature of the dislocation-precipitate interaction, include strong dependence of the CRSS on temperature, dislocation climb and precipitate phase transformation.
10.1016-j.jnucmat.2006.02.069	5	materials; thermal; heat; properties; material; welding; sintering; fusion; strength; laser; heat sink; thermal conductivity; mechanical; sink; manufacturing	Tungsten is a promising armour material for plasma facing components of nuclear fusion reactors because of its low sputter rate and favourable thermo-mechanical properties. Among all the techniques able to realise W armours, plasma spray looks particularly attractive owing to its simplicity and low cost. The present work concerns the optimisation of spraying parameters aimed at 4-5 mm thick W coating on copper-chromium-zirconium (Cu,Cr,Zr) alloy substrates. Characterisation of coatings was performed in order to assess microstructure. impurity content, density, tensile strength, adhesion strength, thermal conductivity and thermal expansion coefficient. The work performed has demonstrated the feasibility of thick W coatings on flat and curved geometries. These coatings appear as a reliable armour for medium heat flux plasma facing component.
10.1016-j.jnucmat.2007.01.249	-1		Tungsten coating of 0.2 mm thickness was successfully deposited by vacuum plasma spraying technique on CuCrZr alloy with Ti bonding layer. Microstructure and chemical composition of deposited W were examined. Its thermal response and thermal fatigue properties were studied with active cooling. No cracks and no exfoliation occurred on the W surface after thermal response test with a heat flux from 0 to 8 MW/m(2). It survived up to 200 cycles under 8 MW/m(2). These results indicate that VPS-W coated Ti/CuCrZr is a potential candidate for a high heat resistance armor material on plasma facing components.
10.1016-j.jnucmat.2008.12.138	-1		W fibre-reinforced Cu shows great promise to improve the mechanical performance at high-temperatures compared to conventional Cu-based alloys. Focus was placed on the optimization of the interface to achieve an enhanced adhesion between W fibre and Cu matrix. The interfacial properties were investigated through pull-out measurements of single matrix-coated fibres for different interfacial concepts. The interfacial adhesion of W and Cu is determined solely through mechanical interlocking. Interdiffusion and segregations experiment showed that there are no interface reactions between W and Cu at elevated temperatures. From the investigated interfacial concepts, a stepwise graded transition interface with additional heat treatment was found to achieve the highest interfacial shear strength . The thermal stability of the MMC in thermal cycling tests can be assured by depositing a stepwise graded transition between W fibre and Cu matrix.
10.1016-j.jnucmat.2008.12.249	7	irradiation; shear; grain; ta; deformation; size; radiation; voids; nanocrystalline; simulations; similar; void; temperature; irradiated; boundaries	To investigate the effect of varying temperature irradiation on oxide dispersion strengthened copper alloy (GlidCop CuAl15). heavy ion irradiation was carried out by using 2.4 MeV Cu ions up to 30 dpa in the temperature range of 473-673 K. TEM observation of CuAl15 before irradiation showed high density of small alumina particles and dislocations. After 30 dpa at 673 K constant temperature irradiation, voids were formed. However, voids formation was strongly depended on grain size. On the other hand, by a varying temperature irradiation, the number density of voids was decreased as compared with that of 673 K constant temperature irradiation. The result of CuAl15 is consistent with our previous studies of pure copper irradiated under same irradiation conditions. (c) 2009 Published by Elsevier B.V.
10.1016-j.jnucmat.2009.05.003	-1		Tensile and fracture toughness properties of a precipitation-hardened CuCrZr alloy were investigated in two heat treatment conditions: solutionized, water quenched and aged (CuCrZr SAA), and hot isostatic pressed, solutionized, slow-cooled and aged (CuCrZr SCA). The second heat treatment simulated the manufacturing cycle for large components, and is directly relevant for the ITER divertor components. Specimens were neutron irradiated at similar to 80 degrees C to two iluences, 2 x 10(24) and 2 x 10(25) n/m(2) (E > 0.1 MeV), corresponding to displacement doses of 0.15 and 1.5 displacements per atom (dpa). Tensile and fracture toughness tests were carried out at room temperature. Significant irradiation hardening and plastic instability at yield occurred in both heat treatment conditions with a saturation dose of,.,0.1 dpa. Neutron irradiation slightly reduced fracture toughness in CuCrZr SAA and CuCrZr SCA. The fracture toughness of CuCrZr remained high up to 1.5 dpa (J(Q) > 200 kJ/m(2)) for both heat treatment conditions. Published by Elsevier B.V.
10.1016-j.jnucmat.2009.08.006	2	corrosion; surface; film; electrochemical; films; spectroscopy; layer; current; solution; potential; resistance; composition; x-ray; ions; showed	CuCrZr is a high copper alloy widely used as electrical and thermal conducting material, especially in heat exchangers in nuclear reactors. In this respect, the physical and fatigue properties of CuCrZr have been extensively studied. The electrochemical behavior of CuCrZr, on the other hand, has not been adequately investigated. In the present study, the effect of pH on the corrosion behavior of CuCrZr in aqueous solutions without and with chloride (0.6 M NaCl) was studied. The pH of the solutions is found to exert significant influence on the corrosion behavior of CuCrZr. In acidic solutions without chloride, the corrosion of CuCrZr is ascribed to active dissolution with soluble products. In neutral and alkaline solutions without NaCl, the presence of oxides on the surface of CuCrZr leads to a noble shift in corrosion potential and passivation results in increased corrosion resistance. In chloride solutions at various pH values, the chloride ions influence the formation of the surface layers and the anodic dissolution process during polarization. At high pH, CuCrZr shows significant passivity and high corrosion resistance due to the growth Of Cu2O/Cu(OH) film which hinders further dissolution whereas at low pH the corrosion resistance is lowered due to active dissolution of Cu.
10.1016-j.jnucmat.2010.12.157	-1		The effects of manufacturing thermal cycle on the various mechanical properties of CuCrZr were investigated. Vickers hardness was changed with an aging temperature in an identical manner with the strength change in a wide range of heat treatment. The change of Charpy impact energy with an aging temperature exhibited an opposite trend to the changes of the strength and hardness. At least in terms of the impact energy of CuCrZr, aging at a higher temperate would be preferable if the strength of CuCrZr could be maintained higher than the limitation value after the completion of the fabrication of ITER first wall. The fatigue life of CuCrZr was influenced to a certain extent by the cooling rate and the aging temperature. Especially in the higher strain amplitude, the contribution of the elastic and plastic components to the fatigue response was dependent on the yield strength which is determined by the aging temperature.
10.1016-j.jnucmat.2011.12.012	-1		A model for plastic deformation in pure copper taking work hardening, dynamic recovery and static recovery into account, has been formulated using basic dislocation mechanisms. The model is intended to be used in finite-element computations of the long term behaviour of structures in Cu-OFP for storage of nuclear waste. The relation between the strain rate and the maximum flow stress in the model has been demonstrated to correspond to strain rate versus stress in creep tests for oxygen free copper alloyed with phosphorus Cu-OFP. A further development of the model can also represent the primary and secondary stage of creep curves. The model is compared to stress strain curves in compression and tension for Cu-OFP. The compression tests were performed at room temperature for strain rates between 5 x 10(-5) and 5 x 10(-3) s(-1). The tests in tension covered the temperature range 20-175 degrees C for strain rates between 1 x 10(-7) and 1 x 10(-4) s(-1). Consequently, it is demonstrated that the model can represent mechanical test data that have been generated both at constant load and at constant strain rate without the use of any fitting parameters.
10.1016-j.jnucmat.2013.05.017	-1		A SiC long fiber-reinforced copper composite offers a beneficial combination of high strength and high thermal conductivity at elevated temperatures. Both properties make the composite a promising material for the heat sink of high-heat-flux components. In this work, we developed a novel Cu/SiCf composite using the Sigma fiber. Based on HIP technique, a metallurgical process was established for fabricating high quality specimens using a TiC interface coating. Extensive tensile tests were conducted on the uni-directionally reinforced composite at 20 degrees C and 300 degrees C for a wide range of fiber volume fraction (V-f). In this paper, a large amount of test data is presented. The transversal thermal conductivity varies from 260 to 130 W/mK at 500 degrees C as V-f is increased from 13% to 37%. The tensile strength reached up to 1246 MPa at 20 degrees C for V-f=37.6%, where the fracture strain was limited to 0.8%. The data of both elastic modulus and ultimate strength exhibited a good agreement with the rule-of-mixture predictions indicating a high quality of the materials. The strength of the composite with the Sigma fibers turned out to be superior to those of the SCS6 fibers at 300 degrees C, although the SCS6 fiber actually has a higher strength than the Sigma fiber. The fractographic pictures of tension test and fiber push-out test manifested a sufficient interfacial bonding.
10.1016-j.jnucmat.2014.07.054	-1		Irradiation of dilute Cu-W alloys with 1.8 MeV Kr+ between 300 K and 573 K is found to induce nucleation of a high density of W nano-precipitates. HRTEM and aberration-corrected STEM reveal that the similar to 3 nm precipitates have a preferred orientation relationship with the matrix. A variant of the Bain relationship exists with preferred alignment occurring along Cu[220] || W[010], with small angular differences amongst the particles, which is compensated by interfacial dislocations or strain. The formation mechanism for such an orientation relationship is rationalized on the basis that small W clusters form within the local melt of an energetic displacements cascade, resulting in the partial alignment of the nanoprecipitates with the Cu lattice as the Cu solidifies.
10.1016-j.jnucmat.2015.12.024	-1		Copper canisters are planned to be used for final disposal of spent nuclear fuel in Sweden. The canisters will be exposed to slow plastic straining over extensive periods of time. To be able to predict the mechanical properties a range of basic models have previously been developed for copper with and without phosphorus (Cu-OFP, Cu-OF). Already with the small amount of phosphorus added in the canisters (60 wt. ppm) dramatic improvements in the measured creep strength and the creep ductility are found. The basic models are further developed in the present paper. The influence of phosphorus on slow strain rate tests is analysed. It is shown that the main effect of phosphorus is that it prevents brittle rupture, which is modelled by taking creep cavitation into account.
10.1016-j.jnucmat.2018.04.012	-1		Precipitation hardened CuCrZr will be used in heat-sink components in the ITER tokomak and is a primary candidate for EU DEMO. The measurement of mechanical properties of irradiated CuCrZr using conventional, standardised techniques is difficult due to the challenges involved in working with radioactive material and the relatively large specimen size required. Spherical nano-indentation offers a technique to measure stress-strain properties from far smaller volumes than conventional tests. In this work, CuCrZr has been heat-treated at different temperatures to vary the Cr precipitate size and spacing. Spherical nano-indentation using multiple tip radii was then used to produce stress-strain curves for all samples, from which values of initial flow stress were calculated. It was found that there was a strong indentation size effect (ISE) in the stress required to initiate plasticity, however at higher indentation strains the flow stress became constant for tip radii, R, >= 8 mu m. This suggests that at the initiation of plastic deformation the ISE is dominated by dislocation source activation but in later stages the interaction with microstructural material length-scales dominate the measured mechanical strength . The mechanical response of these small-scale tests is governed by multiple mechanisms, which convolute interpretation of data and must be considered when measuring the effects of irradiation on the mechanical properties. Crown Copyright
10.1016-j.jnucmat.2018.10.037	2	corrosion; surface; film; electrochemical; films; spectroscopy; layer; current; solution; potential; resistance; composition; x-ray; ions; showed	Copper (Cu) materials are extensively used as heat sinks and sealing gaskets in fusion devices because they have the properties of good thermal and electrical conductivity and high plasticity. Meanwhile, liquid lithium (Li) is considered as a potential blanket coolant and tritium breeder and/or plasma facing material in fusion devices. Studying the corrosion characteristics of Cu materials by liquid Li under extreme fusion conditions is important because the corrosion of Cu by liquid Li may affect simultaneous application of these materials in fusion devices. The corrosion behavior of Cu in static liquid Li at 620 K for 15 h under high vacuum was investigated. After exposure to liquid Li, the weight loss rate of Cu in liquid Li is 466.1 g m(-2) h(-1), which is equivalent to 458.7 mm.a(-1) for the average corrosion depth rate. The entire surface of each specimen was seriously damaged. Visible grain boundary corrosion was observed on the surface of the specimens. Also, Cu debris entered the liquid Li from the corroded surface, resulting in considerable Cu loss from the specimen. These results demonstrate a corrosion protection grade of Cu in liquid Li of 10, Cu cannot withstand the corrosion of liquid Li under the given conditions. Additionally, the corrosion process of Cu in liquid Li at 620 K under high vacuum was studied using the Large-scale Atomic/Molecular Massively Parallel Simulator (LAMMPS). The results from these simulations indicate that the corrosion of Cu in liquid Li is induced via physical dissolution and intergranular corrosion, where intergranular corrosion is the dominant mechanism.
10.1016-j.jnucmat.2019.01.026	-1		In search to identify extremely stable materials to perform the collimation function of the 7-TeV proton beam halo at the Large Hadron Collider (LHC), oxide dispersion strengthened (DS) copper alloys were explored. These internally oxidized copper alloys known as GlidCop are also leading candidates for high heat flux applications in fusion reactors and as divertor and first wall structure in ITER. These considerations have led to an extensive body of research on neutron-induced changes in the microstructure and physio-mechanical properties. This study focused primarily on the damage induced by 200 MeV protons on as wrought and cold-worked GlidCop Al15 DS copper ally selected as a candidate material of the LHC beam collimation structure to damage levels up to similar to 10 displacements-per-atom (dpa) and irradiation temperatures up to -600 degrees C. For reference, low dose spallation neutron damage at sub-zero irradiation temperature was included in the study. Proton irradiation effects on dimensional stability, mechanical behavior, electrical resistivity and X-ray diffraction-based microstructural changes are presented in the paper. GlidCop Al15 exhibited excellent thermal stability and superior to pure Cu resistance to conductivity loss. Proton irradiation-induced hardening and embrittlement at distinct irradiation temperature regimes were shown to follow similar trends to what was reported under neutron exposure to even higher dpa damage. At T-irr similar to 600 +/- 20 degrees C the cold-worked DS copper alloy exhibited softening accompanied by elongation reduction while at T-irr similar to 200 +/- 10 degrees C the as-wrought experienced hardening with elongation increase. High resolution X-ray diffraction revealed that even low-dose neutron irradiation has a strong influence on the size and distribution of dispersed Al2O3 particles.
10.1016-j.jnucmat.2019.151753	-1		With the goals of exploring the feasibility of replacing Zr with Fe and P in Cu-Cr-Zr alloys and developing Cu-Cr-Fe-P alloys with excellent mechanical and electrical properties, the effects of Fe and P additions on the microstructures and properties of the as-cast, cold-rolled and aged Cu-0.8Cr alloys are investigated. The results indicate that adding Fe and P into the Cu-0.8Cr alloy can promote the precipitation of a large amount of fine, uniformly dispersed Cr and Cr3P particles. From Cu-0.8Cr to Cu-0.8Cr-0.17Fe-0.048P, the area fraction of precipitates increases from 3.1% to 6.3% while their average diameter reduces from 1.6 mu m to 1.4 mu m. When subjected to 95% cold rolling plus 450 degrees C aging for 1 h, the Cu-0.8Cr-0.17Fe-0.048P alloy exhibits a Vickers hardness of 140.4 HV and an electrical conductivity of 73.2%IACS, higher than 96.7 HV and 58.4%IACS in the Cu-0.8Cr alloy. Among three different processing routes investigated, the one with initial 50% cold rolling -> aging at 500 degrees C for 1 h -> final 95% cold rolling allows the Cu-0.8Cr-0.17Fe-0.048P alloy to gain most in both its tensile strength (569 MPa) and electrical conductivity (64%IACS). The findings in this work provide insights to composition and processing designs for new CueCr alloys with high strength and electrical conductivity.
10.1016-j.jnucmat.2020.152063	15	aging; strength; conductivity; electrical conductivity; electrical; mpa; treatment; strengthening; degrees; cu-; cold; precipitation; tensile strength; tensile; iacs	Cu-Cr-Zr alloy has been widely considered to be used as heat sink materials in the fusion reactor due to its superior properties. However, Cu-Cr-Zr alloy suffers significant creep deformation and softening as the temperatures is above 300-400 degrees C. Advanced Cu alloys with high strength, high conductivity and high thermal stability need to be developed to meet the requirements in the future fusion reactor. In this work, a novel Cu-Cr-Zr-Fe-Ti-Y alloy was designed and prepared by vacuum induction melting, followed by homogenization treatment, hot-rolled, solid solution, cold-rolled and aging treatments. Tensile properties, hardness and electrical conductivity of the alloys aging at different temperatures were tested. The alloy aged at 500 degrees C exhibits excellent tensile strength up to 541 MPa and high electrical conductivity of 82% IACS. The alloy maintains high tensile strength even annealing at 500 degrees C for 72 h . The microstructures of the alloy were characterized by optical, scanning and transmission electron microscopy, and it is found that the high thermal stability of the novel alloy is mainly contributed to two reasons. One is the high friction of low-Sigma CSL grain boundaries (mainly Sigma 3) with low energy detected in the matrix, which are difficult to slid and have higher thermal stability than general high-angle grain boundaries. Another one is the two kinds of high-density precipitates detected in the matrix. The larger Cr1.4Fe particles are semi-coherent with the matrix, and the orientation relationship is [011](Cu)//[011](Cr1.4Fe), (100)(Cu)//(01 (1) over bar)(Cr1.4Fe) and (11 (1) over bar)(Cu)//((2) over bar1 (1) over bar)(Cr1.4Fe). The smaller Cr particles are coherent with the matrix, and the orientation relationship is [011](Cu)//[(1) over bar 11](Cr), (100)(Cu)//(01 (1) over bar)(Cr) and (0 (1) over bar1)(Cu)//(211)(Cr). The strengthening mechanism of the alloy was analyzed in details, and the calculation yield strength (480 MPa) is well coincident with the experimental value (473 MPa).
10.1016-j.jnucmat.2020.152775	-1		Cu-Cr-Zr alloy, a copper-based precipitation hardened alloy with good electrical and thermal conductivities and moderate strength at elevated temperatures, is being considered for many advance technological applications including fusion energy programme. Ageing study on indigenously manufactured Cu-Cr-Zr alloy (0.7-0.8 wt% Cr, 0.08-0.11wt% Zr, balance Cu) has been performed in the temperature range of 673 K-773 K and time from 30 min to 5 h to find the peak ageing conditions for this alloy. The peak ageing conditions were achieved at 3 h of heat-treatment at 723 K. An attempt has been made to identify the precipitates using analytical transmission electron microscopy and to classify them based on morphology, sizes and distribution. Besides the larger precipitates of Cu5CrZr, two clearly distinct sizes of smaller precipitates were observed. Electron microscopy revealed that the larger precipitates are having spherical and cuboidal morphology. The temperature dependent flow behavior of Cu-Cr-Zr alloy in peak aged condition was evaluated in the range of 298 K to 1073 K in 100 K interval. The dislocation arrangement and the dislocation precipitate interaction were examined to understand the contribution of the precipitates in strengthening and also in work hardening behavior of the alloy.
10.1016-j.jnucmat.2021.152956	-1		High temperature, creep resistant heat sink materials represent a critical need for plasma facing components in future fusion reactors. In this study, we employ direct current sintering (often referred to as spark plasma sintering) to produce a Cu-Cr-Nb-Zr (CCNZ) alloy from gas-atomized feedstock powder with tailored precipitate distributions for enhanced stability and creep resistance. Microstructure was characterized by synchrotron X-ray diffraction, small angle X-ray scattering, and electron microscopy techniques. We report a multi-modal precipitate distribution containing submicron Cr (similar to 493 nm) and Cr2Nb (similar to 90 nm) precipitates at grain boundaries and a high density of nanoscale Cr (similar to 8 nm) precipitates homogeneously distributed through the Cu matrix. By comparing the as-sintered and aged microstructures, precipitation kinetics are discussed in the context of dislocation networks due to the high sintering pressures biasing precipitate formation and the role of subsequent recovery and recrystallization. Due to the presence of the multi-modal precipitate distribution, the sintered CCNZ alloy exhibited a high hardness of 133.2 HV while retaining an appreciable thermal conductivity of 298.4 W/m.K and electrical conductivity of 74.6% relative to the International Annealed Copper Standard.
10.1016-j.jnucmat.2021.153484	10	composites; nanoparticles; strength; matrix; high; strengthening; particles; conductivity; composite; electrical; mpa; sintering; ods; grains; mechanical	Oxide dispersion-strengthened copper (ODS-Cu) alloys with yttrium oxide nanoparticles are promising heat sink materials in fusion reactor due to their high strength, thermal conductivity and thermodynamic stability. The particle size and number density of oxide nanoparticles can be improved via addition of microalloying element. In this study, the atomized Cu-Y alloy, Al and Cu2O were used as the Y source, the microalloying element and the oxidant material, respectively, to fabricate ODS-Cu alloy by mechanical alloying method. After spark plasma sintering and annealing, a ODS-Cu alloy with a microstructure containing Y4Al2O9 nanoparticles homogeneously distributed in Cu(Al) solid solution matrix was success-fully fabricated. It is found that a crystallographic orientation relationship of (3 (1) over bar2)(Y4Al2O9) parallel to(1 (1) over bar1)(Cu(Al)) was formed between Y4Al2O9 nanoparticles and Cu(Al) matrix and the lattice mismatch was 0.337%. The small lattice mismatch reduced the nucleation barrier for Y4Al2O9 nanoparticles so a mean particle size of 4.8 nm and a number density of 2.16 x10(24) m(-3) were obtained in the alloy. Consequently, the microhard-ness was enhanced via Hall-Petch strengthening, dislocation strengthening and dispersion strengthening. The softening temperature of ODS-Cu alloy was improved to higher than 1000 degrees C due to the thermodynamic stability and the pinning effect of Y4Al2O9 nanoparticles. In addition, the thermal conductivity of Cu-1Y-9Al-0.3Cu(2)O alloy is close to other copper alloys as the volume fraction of Y4Al2O9 nanoparticles is limited. Cu-1Y-9Al-0.3Cu(2)O alloy provides a good overall performance, which may be used as heat sink materials under severe conditions.
10.1016-j.jnucmat.2022.154016	-1		In order to reflect the superiority of using Cu 6 Y as the Y 2 O 3 source, three different Y sources addition, direct Y 2 O 3 by conventional mechanical alloying process, pure metal Y and Cu 6 Y compound by in-situ fabrication method, were compared in the ODS-Cu with 1.5 wt% Y 2 O 3 . It was found that compared to Y 2 O 3 or pure metal Y, the brittle Cu 6 Y played the roles of both suitable Y precursor to enhance Y dissolution and process control agent (PCA) to suppress the growth of mechanical alloying (MA) powders. The alloyed layer was thickened with the MA time, and the further MA gradually becomes difficult. It is inefficient to fully alloy the MA powders only by prolonging milling time. The samples by in-situ fabrication method (Y and Cu 6 Y sourced) had more contaminations with Fe, because of the oxidation of milling mediums by Cu 2 O, which was used to oxide the Y precursors to form the Y 2 O 3 . The contaminations contributed to the hard prior particles boundaries where fracture took place during the tensile tests, resulting in the poor tensile performance for the samples by in-situ fabrication method. Considering that the Cu 6 Y sourced sample by in-situ fabrication method formed fine and high dense dispersive Y 2 O 3 particles with the size of 19 +/- 7 nm and a high number density of 1.8 x 10 21 /m 3 , it has a larger potential for improvement once the means to reduce Fe impurities and holes are developed.
10.1016-j.jnucmat.2022.154153	7	irradiation; shear; grain; ta; deformation; size; radiation; voids; nanocrystalline; simulations; similar; void; temperature; irradiated; boundaries	Helium (He) generated during irradiation is notorious for inducing volumetric swelling and grain bound-ary embrittlement. It is imperative to design advanced materials with effective capability to manage He. Here, we report a largelydifferent bubble swelling behavior in Cu50Ag50, Cu45Ag45Fe10 and Cu33Ag33Fe34 nanocomposites with similar grain sizes. In situ He pre-injection leads to similar He bubble size and den-sity in all three alloy systems. After subsequent Kr irradiation, the average bubble size and swelling in Cu33Ag33Fe34 is much less than Cu50Ag50. Additionally, while bubble size is much greater along triple junctions and grain boundaries than in matrix in Cu50Ag50, the bubble size at the triple junctions in Cu33Ag33Fe34 is much less, suggesting the vital role of Cu-Ag-Fe triphase triple junctions and phase boundaries in managing He. The present study provides new perspective for improving the radiation tolerance of nanocrystalline alloys by microstructure design.
10.1016-j.jnucmat.2023.154587	-1		The effect of neutron irradiation on tensile properties and fracture mode has been investigated for several advanced CuCrZr alloys in the frame of the European fusion material development program. Five material grades utilizing different strengthening principles have been exposed to neutron irradiation up to similar to 2.5 dpa (displacement per atom) in the target operational temperature range of 150-450 degrees C. The strengthening mechanisms are based on the application of: i) tungsten particles; ii) tungsten foils (laminate structure); iii) tungsten fibers; iv) Y2O3 particles; v) vanadium addition (0.22%). Neutron irradiation was performed in the BR2 material test reactor inside the fuel channel in order to maximize the fast neutron flux. The upper irradiation temperature of 450 degrees C was selected to validate the ability of the pre-selected advanced grades to sustain the high temperature irradiation, since the baseline ITER specification CuCrZr is known not to retain sufficient tensile strength above 400 degrees C in non-irradiated conditions and shows strong irradiation induced softening above 300 degrees C. Neutron irradiation at 150 degrees C caused severe embrittlement of tungsten-copper laminates as well as a considerable reduction of the total elongation of all other grades. The irradiation at 450 degrees C led to the reduction of the yield strength and ultimate tensile strength (i.e. irradiation softening) in the vanadium-doped alloy similar to CuCrZr, while all other materials preserved or increased their strength (irradiation hardening). The fracture surfaces of the tested samples were analysed to investigate the modification of the deformation mechanisms in each particular case.
10.1016-j.jnucmat.2024.155205	-1		Oxide dispersion strengthened Cu (ODS Cu) alloys possess a high potential to be used as promising heat sink materials for the divertor system in DEMO fusion reactors. Considering their future application in fusion reactor divertor systems, mass-production of ODS Cu alloys is a must. The purpose of this study is to investigate the feasibility of large-scale production of ODS Cu alloys by improving the production process based on the already established mass-production process of ODS Fe alloys in cooperation with the steel manufacturer Kobelco Research Institute. After optimization of the mechanical alloying (MA) parameters, a large-scale production of ODS Cu powders was successfully achieved with a recovery rate of over 90% and around 1Kg powder in one batch production using an industry-level attritor ball mill cooled by circulating water. The mass-produced ODS Cu alloys were comprehensively characterized, including mechanical properties, microstructure and thermal diffusivity, and a new concept of low-energy ball milling was proposed based on the results to realize the massproduction of ODS Cu alloys.
10.1016-j.jnucmat.2024.155328	-1		This work prepared the Cu-Y2O3 alloy through mechanical alloying and spark plasma sintering. Based on the insitu reaction principle, Y salts were used as a precursor of Y2O3 dispersoid instead of pure Y powder, and the influence of different Y salts on the microstructure, mechanical, and physical properties of the copper matrix was researched. The results indicate that Y salts can effectively prevent the cold welding effect of pure Y metal powder, thereby improving the homogeneity and refinement effect of alloying. Among different Y salts samples, Y(NO3)3 & sdot;6H2O and Y2(SO4)3 & sdot;8H2O may cause varying degrees of contamination to the copper matrix, affecting the material properties. In comparison, Y2(CO3)3 has the advantage of low decomposition temperature and the decomposition product CO2 does not react with the copper matrix. It successfully refined the average particle size of Y2O3 from 8.8 f 3.7 nm to 5.5 f 2.8 nm, increased the number density from 2.37 x 1021/m3 to 7.46 x 1021/ m3, and obtained a tensile strength of 291 MPa and an elongation of 19.8 % at room temperature, with a thermal conductivity of 322 W/(m K) at 400 degrees C for the Cu-Y2O3 alloy. This validates the feasibility of combining Y salts with mechanical alloying. The preparation of high-strength, high-conductivity Cu alloys holds significant reference value.
10.1016-j.jnucmat.2024.155334	-1		In nuclear power plants, CuCrZr alloy and pure copper (T2) are widely used as the structural materials and service at high temperatures, and the comprehensive understanding of the mechanical properties is essential. In this paper, the small punch test (SPT) is used to understand the variations of mechanical properties and fracture mechanism with temperature for them. The soft temperature of CuCrZr alloy is identified as 400 degrees C, with the sharp decrease in SPT strength parameters and fracture energy, which is caused by the oxidation. The SPT fracture mode changes from the central line crack to O shape circumferential crack, and the mixed oxidation and plastic deformation fracture mechanism is observed at 500 degrees C. The soft temperature of T2 is 300 degrees C, with the sharp decrease in the SPT fracture displacement. The O shape circumferential crack and the necking phenomenon are unchanged for the fracture mode of T2, but the fracture mechanism changes from transgranular fracture to intergranular fracture, with increase in temperature. This paper describes the deformation behaviour of CuCrZr alloy and T2 using SPT as a function of temperature, investigates the fracture behaviour and attempts to bring out the effect oxidation during high temperature tests.
10.1016-j.jnucmat.2025.155645	7	irradiation; shear; grain; ta; deformation; size; radiation; voids; nanocrystalline; simulations; similar; void; temperature; irradiated; boundaries	We investigate the effect of high-temperature helium (He) implantation on microstructural evolution in physicalvapor-co-deposited nanocomposite thin films of copper (Cu) and molybdenum (Mo). The microstructure morphologies of He-implanted and He-free domains are characterized using transmission electron microscopy and statistical analysis. High implantation temperatures (500 degrees C and 750 degrees C) lead to coarsening of Cu and Mo domains and their eventual reorientation. The microstructure evolution in He-implanted and He-free domains is comparable, indicating that implantation-induced defects do not accelerate the coarsening of the nanocomposite as compared to annealing alone. This observation contrasts with previously reported effects of implantationinduced defects on single-phase nanocrystalline metals, which include enhancement of grain growth by increasing self-diffusivity or its inhibition by pinning of grain boundaries.
10.1016-j.jnucmat.2025.155992	10	composites; nanoparticles; strength; matrix; high; strengthening; particles; conductivity; composite; electrical; mpa; sintering; ods; grains; mechanical	Cu-15 wt. % W composites were successfully produced via a feasible and simple strategy, achieving an excellent combination of ultrahigh strength and high thermal stability. These composites demonstrate potential as candidates for heat sink materials in the fusion reactor. In this work, Cu-15 wt. % W composites with bimodal particle size distribution were fabricated by conventional mechanical alloying (MA) and spark plasma sintering (SPS) followed by hot rolling and annealing processes. The ultimate tensile strength, total elongation, electrical conductivity and thermal conductivity are 709 MPa, 13.7 %, 60.8 %IACS and 291.3 W/(m & sdot;K), respectively. Cu-15 wt. % W composite also has excellent thermal stability with the ultimate tensile strength decreasing only 3.4 % even when the annealing temperature is increasing to 700 degrees C. The excellent performance of the composite is due to the fine, high-density and bimodal size distribution reinforced particles (fine W particles with the average size of 27.5 nm and ultrafine W particles with the average size of 4.6 nm) in Cu matrix. The large-sized particles stabilize the microstructure against the effect of elevated temperature by pinning grain boundaries. Forming small-sized particles offers higher density strengthening phases improving the storage capability of dislocations. The combination of bimodal particle size distribution acts as the very powerful inhibition on the movement of dislocations and grain boundaries. Our study provides an effective route to achieve high performance of Cu matrix composites.
10.1016-j.jobe.2023.107825	3	sma; shape; shape memory; memory; smas; superelastic; bars; damping; cu-al-mn; mechanical; bending; applications; numerical; sma bars; material	To improve seismic capabilities and to reduce post-earthquake residual deformation of precast concrete frames, a novel self-centring hybrid connection (SCHC) composed of a rotational friction hinge device (RFHD) and four self-centring buckling-restrained dampers (SC-BRDs) was proposed and investigated for the dry type precast concrete beam-column joints in this study. The configuration and working principles of the SCHC were first illustrated. The effects of solution heat treatment procedures, strain amplitudes, and cycle numbers on the uniaxial cyclic behaviour of prepared Cu-Al-Mn SMA plates were also tested for the SCHC application. Finite element models of the RFHD, SC-BRD, and novel SCHC were subsequently established and preliminarily verified, followed by parametric analyses on several crucial design parameters of the SCHC to optimize its mechanical performance. Results shown that the self-centring ability and strength degradation resistance of the prepared Cu-Al-Mn SMA plates can be significantly improved by subjecting appropriate solution heat treatment procedures. The SMA core element thickness, initial post-tensioning force of high-strength bolt, and distance between SMA and rotation centre are suggested to be designed within the range of 8 mm-10 mm, 565 kN-705 kN, and 120 mm-130 mm, respectively, to achieve appropriate energy dissipation and self-centring performance of the proposed SCHC. The RFHD and SC-BRD can be conveniently replaced after damage in earthquake, which is conducive for rapid repair of the prefabricated concrete structures. Overall, the proposed SCHC shows excellent seismic mitigation ability, self-centring capability, and repairability. The proposed SCHC can provide a reference for the application of some important prefabricated concrete structures in requirement of uninterruptible or rapidly restorable building functions after high seismic effects.
10.1016-j.jpcs.2005.11.012	11	glass; bulk; metallic; bulk metallic; gfa; bmg; glassy; metallic glass; ability; bulk metallic glass; amorphous; addition; crystallization; mm; glass-forming	The corrosion behavior of Cu95-xZrxAl5 (x = 40, 42.5 and 45 at%) in 1 N HCl, 3 mass% NaCl and 1 N H2SO4 solutions was studied. As Zr content increases, the corrosion resistance is slightly enhanced. In order to improve the corrosion resistance of the Cu-Zr-Al glassy alloy, Nb was selected to substitute Cu. Although the supercooled liquid region AT, of the Cu-Zr-Al glassy alloys decreases with increasing Nb content, the alloys still retain high glass-forming ability and bulk glassy samples with 1.5 mm diameter can be obtained when up to 5 at% Nb was added. It is found that the addition of Nb results in improvement of the corrosion resistance of the glassy Cu-Zr-Al alloys.
10.1016-j.jpcs.2009.05.003	13	clusters; atomic; glass; atoms; composition; dynamics; metallic; icosahedral; glasses; simulations; molecular; cu-zr; molecular dynamics; metallic glasses; structural	We have performed first-principles calculations using full potential linearized augmented plane wave (FP-LAPW) method within density functional theory (DFT) to investigate the fundamental properties of CuxAg1-xI alloys. We used both GGA96 [J.P. Perdew, K. Burke, M. Ernzerhof, Phys. Rev. Lett. 77 (1996) 3865.] and EVGGA [E. Engel, S.H. Vosko, Phys. Rev. B. 47 (1993) 13164.] generalized gradient approximations of the exchange-correlation energy that are based on the optimization of total energy and corresponding potential. Quantities such as lattice constants, bulk modulus, band gap, density of occupied states and effective mass were calculated as a function of copper molar fraction x. These parameters were found to depend non-linearly on alloy composition x, except the lattice parameter, which follows Vegard's law. The microscopic origins of the gap bowing were explained using the approach of Zunger and co-workers; we have concluded that the band-gap energy bowing was mainly caused by the chemical charge-transfer effect and the volume deformation, while the structural relaxation contribute to the gap bowing parameter at smaller magnitude. The calculated phase diagram shows a broad miscibility gap for this alloy with a high critical temperature.
10.1016-j.jpcs.2017.01.012	4	transformation; martensite; martensitic; phase; shape; beta; memory; shape memory; temperature; temperatures; martensitic transformation; gamma; transformation temperatures; effect; thermal	The phase stability in the Cu-9 wt%Al-10 wt%Mn-3 wt%Ag alloy was analyzed using differential scanning calorimetry (DSC), X-ray diffractometry (XRD), transmission electron microscopy (TEM), high-resolution transmission electron microscopy (HRTEM), optical microscopy (OM) and microhardness measurements with quenching temperature. The results showed that the presence of silver alters the phase stability range and enhances the effect of bainite precipitation on the microhardness values of the Cu-9 wt%Al-10 wt%Mn-3 wt%Ag alloy.
10.1016-j.jpcs.2018.05.036	-1		In this study, the thermal stability and Mn carbide formation were investigated in amorphous Cu-Mn/C films with potential applications as interconnect layers. Amorphous Cu-Mn films (with 50 and 70 at% Mn content) were deposited by direct current (DC) magnetron sputtering at room temperature. Evaporated carbon foils were used as substrates to model low-x carbon doped oxides in their reaction with Cu-Mn films. In-situ transmission electron microscopy indicated that the amorphous state was stable below 300 degrees C, where the films crystallized into Cu(Mn) and alpha-Mn based solid solutions. The Mn carbide phases appeared at 400 degrees C where it was accompanied by the disappearance of the alpha-Mn phase and a decrease in the Mn content of the Cu(Mn) phase. The Mn23C6 and Mn5C2 carbide phases were present from 400 degrees C to 500 degrees C, and Mn5C2 and Mn7C3 carbides in the temperature range of 500-600 degrees C. The Mn5C2 carbides exhibited significant grain growth in the temperature range of 400-600 degrees C. The activation energies for Mn5C2 growth were 101 +/- 20 and 88 +/- 22 kJ/mol in the films containing 50 and 70 at% Mn, respectively, thereby indicating that growth was facilitated by a higher Mn content. In addition to carbide formation, surface oxidation occurred in the system. Thermodynamic considerations indicate that Mn carbide formation can only occur in the Cu-Mn-C-O system when the Mn is not fully oxidized and free metallic Mn atoms remain.
10.1016-j.jpcs.2019.109074	4	transformation; martensite; martensitic; phase; shape; beta; memory; shape memory; temperature; temperatures; martensitic transformation; gamma; transformation temperatures; effect; thermal	In this study, the kinetics of martensite decomposition and the microstructural evolution of the Cu79.7Al19.2Gd1.1 alloy were evaluated based on microhardness measurements as a function of the aging time and quenching temperature, as well as differential scanning calorimetry, scanning electron microscopy, and X-ray diffractometry. The results indicated that the alpha(2)-(Cu4Al) phase was more rapidly disordered than the beta(1)'-(Cu3Al) phase in the Cu81.1Al18.9 alloy. The addition of Gd to the Cu81.1Al18.9 alloy seems to increase the a phase precipitation and the martensite phase decomposition rates. A new thermal event was observed in the Cu79.7Al19.2Gd1.1 alloy after aging at 150 degrees C for 14400min (10 days). Changes in the phase transition mechanism also occurred during aging from 350 degrees C for the Cu81.1Al18.9 alloy and from 300 degrees C for the Cu79.7Al19.2Gd1.1 alloy.
10.1016-j.jpcs.2021.110082	-1		The thermodynamic stability and mechanical strength of grain boundaries (GBs) govern many key properties of nanocrystalline or polycrystalline metals. In order to design novel Cu-based alloys with extraordinary properties and broaden the application scopes of Cu alloys, it is essential to clarify the effects of GB structure and composition on the stability and cohesion of Cu GBs. Firstly, the GB energies and works of separation of 12 Cu symmetrical tilt GBs with various GB orientations were figured out by using first-principles calculations, to link the GB properties with structures. Our results shown that the GB energies and works of separation of 12 Cu GBs are notably anisotropic. The GB energies for these GBs have an inverted and linear relationship with their works of separation. As to GB composition, the segregation tendencies of 8 alloying elements (Mg, Ca, Cr, Ni, Zn, Zr, Ag and Sn) in the Cu Sigma 5 [001](210) symmetrical tilt GB and their cohesive and embrittling effects on the GB were studied. It was found that all considered solutes excluding the element Ni can segregate to the Cu GB and thus play stabilizing roles into the Cu GB. Among 8 solutes, only the Zr and Cr segregations can improve the thermodynamic stability and fracture strength of Cu GB simultaneously. The GB strengthening effects of Zr and Cr segregations was attributed to their significant chemical contributions to the embrittling potencies, i.e., the presence of covalent-like bonding features in newly-formed Cu-Zr/Cr bonds. The reduction/increase of antibonding/bonding states below the Fermi level in Cu-Zr/Cr atomic pairs should be responsible for the GB stabilizing effects of Zr and Cr segregations.
10.1016-j.jpcs.2022.110864	-1		Effects of Ag on the phase transformation of Cu3Sb were investigated through scanning electron microscopy, energy-dispersive X-ray spectroscopy, and high-temperature X-ray diffraction (XRD) measurements. Observations of Cu-Sb-Ag alloys following heat treatment at 500 degrees C revealed that Ag dissolved up to 11 at% in a cubic beta-Cu3Sb phase stable only at high temperatures. XRD measurements confirmed that while a transformation from the beta-Cu3Sb phase to orthorhombic epsilon-Cu3Sb phase occurred at 440 degrees C in the binary system, the transformation occurred below 380 degrees C in the alloy containing 5% Ag, suggesting the enhanced stability of the beta-Cu3Sb phase owing to Ag. Furthermore, during measurements above 420 degrees C on alloys with a composition consistent with that of Cu3-xAgxSb containing 8-14% Ag (i.e., x = 0.32-0.56), the formation of a new alloy phase with a hexagonal structure (a = 4.3416 angstrom and c = 7.6864 angstrom at 500 degrees C) was observed. The crystal structure of the new alloy phase was inferred to be of the Na3As type, which belongs to the space group P6(3)/mmc. Based on observations of alloys with various compositions, an isothermal section of the Cu-Sb-Ag ternary phase diagram at 500 degrees C was constructed.
10.1016-j.jqsrt.2007.10.007	-1		The mass attenuation coefficients, total interaction cross-sections, effective atomic numbers, effective electron densities and photon mean free paths of the Cu/Zn alloy were determined on the basis of the mixture rule at 356, 511, 662, 835 and 1275 keV gamma-ray energies. The gamma-rays were detected by using an ordinary NaI(Tl) scintillation detection system with a resolution of 10.2% at 662 keV. It was observed that the mixture rule is a suitable method for determination of these parameters. The effective atomic numbers and effective electron densities tend to be almost constant as a function of energy. There is good agreement between experiment and theory, calculated by WinXCom.
10.1016-j.jre.2017.11.006	-1		Cu-0.45Cr-0.2Zr-xLa (x = 0-0.48) alloys were prepared by vacuum casting. The effects of La addition and orientation on the microstructure and properties of the as-cast alloy were investigated by an optical microscope, a scanning electron microscope with an energy dispersive X-ray spectrometer, a tensile testing machine and an electrical conductivity tester. The result shows that the addition of La significantly refines the columnar grainsize and decreases the secondary dendrite arm spacing. Trace addition of La improves the room temperature ultimate tensile strength, elongation and electrical conductivity mainly by purifying during melting and casting. The ultimate tensile strength, elongation and electrical conductivity significantly decrease with the increase of La content due to formation of coarse particles and oxides, which severely harm the performance of the Cu-0.45Cr-0.2Zr-xLa alloys. The Cu-0.45Cr0.2Zr-0.13La alloy possesses a good combination of room temperature ultimate tensile strength, elongation and electrical conductivity. In addition, room temperature ultimate tensile strength and electrical conductivity along transverse direction of the ingot are higher than that along longitudinal direction, which is mainly ascribed to different distribution of grain boundary and grain orientation. (c) 2018 Published by Elsevier B.V. on behalf of Chinese Society of Rare Earths.
10.1016-j.jre.2018.08.001	-1		CuSn powders and TiH2 powders were milled using high energy mechanical milling to prepare Cu-based alloy powders for brazing diamond. And Ce was added to the milled Cu-based alloy powders to improve the wettability. It is found that the wetting angle reaches the minimum value 13.2 degrees and the maximum spreading area 178 mm(2) is achieved when the amount of Ce is 0.75 wt%. And Ce remarkably reduces the surface tension of liquid alloy, which improves the climbing height along the diamond and forms a massive support profile. And the results show that Ce can effectively improve the transverse rupture strength (TRS) due to high wettability. The wear characteristics of the diamonds brazed with Cu-based alloy containing 0.75 wt% Ce mainly consist of integrity, micro-fracture, fracture and rubdown, diamonds pull-out can not easily happen. (C) 2018 Published by Elsevier B.V. on behalf of Chinese Society of Rare Earths.
10.1016-j.jre.2018.08.016	-1		Two kinds of Cu-Al2O3 composites (with and without La) were prepared via mechanical alloying-spark plasma sintering (MA-SPS) method. Microstructure, mechanical properties and electrical resistivity were investigated systematically using metallography, scanning electron microscopy, transmission electron microscopy, mechanical and electrical properties testing. The results indicate that an appropriate amount of La can homogenize the distribution of Al2O3. As such, yield strength, ultimate tensile strength and elongation of Cu-Al2O3-La are greatly increased. Some semi-coherent interface between Cu and Al2O3 is found, which means a low interface energy. The grain shape of Cu changes to irregular band with the addition of La. This change results in a density decrease of grain boundary and reduces electrical resistance. Lanthanum may exist in the form of La2O3.
10.1016-j.jre.2022.10.013	-1		The effects of Ce addition (310 ppm and 1500 ppm) on the microstructure, texture and properties of ultrahigh-purity copper (99.99999%) were systematically studied using scanning electron microscopy (SEM), transmission electron microscopy (TEM) and electron backscattered diffraction (EBSD) analyses, combined with the microhardness and conductivity tests. Regarding the microstructure of the as-cast and as-extruded samples, the addition of Ce refines the grain size of the ultrahigh-purity copper and the refinement effect of 310Ce alloy is greater than that of 1500Ce alloy. This is due to the stronger component supercooling and the accelerated recrystallization caused by lower Ce content. In addition, Ce can react with Cu to form the Cu-Ce eutectic phases, which are deformable during the hot deformation. Furthermore, the added Ce can weaken the texture, showing a variation of brass recrystallization (BR), rotated cube, copper and S texture components, which depends on the recrystallization, the particle stimulated nucleation (PSN) as well as the stacking fault energy (SFE). Most remarkably, the introduction of Ce enhances the hardness of the ultrahigh-purity copper without obviously reducing its conductivity. The major {111} orientations and the stress distributions are responsible for such a superior conductivity of the Ce-containing alloys.
10.1016-j.jssc.2020.121488	-1		In the process of heating, atomic thermal motion causes an increase in Cu or Zn anti-sites and the degree to which atoms randomly occupy sublattices. The disordered solid solution can be separated into partially disordered and fully disordered solid solutions, and the transition from a fully ordered structure to a fully disordered structure of the solid solution should occur as an evolutionary process of atoms that randomly occupy sublattices to different degrees. In this paper, the concept of disorder degree is proposed, and a pseudo-atomic lattice inversion potential method is used to simulate the order to disorder transition of CuZn solid solution. The potential parameters can be obtained using density functional theory (DFT) calculation and Chen's lattice inversion method. The results indicate that the lattice distortion exhibits a quadratic relationship in which the disorder degree weakens the cohesive energy in the order-disorder transition process. The calculated vibrational entropy difference between the fully ordered B-2 and fully disordered A(2) CuZn solid solution is 0.24 k(B)/atom. Furthermore, a new pseudo-atom gamma-(Zn or Cu) system is built to calculate the thermodynamic properties of a non-stoichiometry Cu-Zn alloy system, and the results show that the vibrational entropy, specific heat capacity, and bulk modulus exhibit an approximately linear change with Zn concentration. The vibrational entropy and bulk modulus are sensitive to the phase transition, and the slope mutation facilitates the determination of the phase boundary.
10.1016-j.jssc.2020.121765	-1		First-principles calculations were used to study the effects of several alloying elements X (i.e., Al, Sc, Zn, and Ce) on the de-twinning of Cu alloys. The results show that the nanotwin (Nt) formation energy of Cu-X alloy gradually decreases with the de-twinning, but Ce improve the Nt formation energy and segregation energy of Cu alloys in T4. Furthermore, charge transfer and redistribution were investigated to explore the physical mechanisms of twinning and de-twinning. When the alloying atom is introduced, a local effect is formed in its neighboring regions. The anisotropic distribution of the density charges around Ce improves its bonding strength with Cu atoms, while the Sc atom and Ce atom have a smaller electronegativity and a larger atomic radius, forming strong bonds and high mechanical energy.
10.1016-j.jssc.2024.125176	-1		Phase relations in the ternary system Cu-Ir-B have been experimentally established for the isothermal section at 600 degrees C via electron microprobe and X-ray powder diffraction analyses. Reinvestigation of the binary systems pertinent to the concentration areas of the current study confirmed the existence and crystal structure of compounds alpha-Ir2B3-x and Ir3B4 and indicated slightly higher solubility of Ir in Cu as compared to literature data. The formation of beta-Ir2B3-x was observed from ternary alloys annealed at 800 degrees C. Phase equilibria at 600 degrees C involve two previously reported ternary compounds, CuIr2B2-x (x = 0.52; space group Cmcm) and CuIrB (space group Fdd 2). In addition, a new ternary compound Cu 5+x Ir 5-x B 2 (x = 1.05; space group F 43 m ) was identified in as cast alloys. CuIr2B2-x and CuIrB crystallize with their own structure types while the new compound Cu 5+x Ir 5-x B 2 adopts the Pd5Cu5B2 structure type. The copper iridium borides obtained reveal different motifs of condensation of boron structural units. In the CuIr2B2-x structure, the Ir6 trigonal prisms (partly filled with B) inter-connect in two directions to form 2D layers; the blocks of three layers of prisms interchange along the longer axis of the unit cell with two stacked 44 Cu nets. Closely related arrangements are found in other intermetallic phases such as MAB phases. The building unit of CuIrB is a [BIr4] tetrahedron; the tetrahedra interconnect creating channels with interlinked and slightly waved chains of Cu. In the structure of Cu 5+x Ir 5-x B 2 , the groups of four [BM6] trigonal prisms (condensed through common edges) join via common vertices to form a framework enveloping extensive Cu structural units reminiscent to those, found in the fcc copper lattice (Cu6 octahedron augmented into tetrahedron by adding copper Cu4 tetrahedra). Two ternary compounds, CuIr2B2-x and CuIrB were targeted for analysis of their electronic and band structure, chemical bonding and physical properties (electrical resistivity as a function of temperature). The chemical bonding analysis revealed partially covalent Ir-B bonding in the metal boride subunits in both compounds. According to Bader charges analysis, copper atoms donate their electrons to more electronegative iridium atoms. CuIrB and CuIr2B2-x are expected to be metallic from the DFT calculations with number of bands crossing the Fermi level in both SO and non-SO case in good agreement with resistivity measurements. CuIrB is characterized by a small eDOS of 0.45 states/eV*f.u. on the Fermi level in comparison to a value of 2.75 states/eV*f.u. for CuIr2B2-x. Both compounds are characterized by a low residual resistivity and a low Debye temperature.
10.1016-j.jsv.2015.08.018	3	sma; shape; shape memory; memory; smas; superelastic; bars; damping; cu-al-mn; mechanical; bending; applications; numerical; sma bars; material	Quasi-zero-stiffness (QZS) vibration isolators avoid excessive deformation due to gravity, a critical issue in vertical vibration isolation, by providing restoring force with high initial stiffness and low tangent stiffness around the static equilibrium position. Effective use of geometric nonlinearity often plays a central role in QZS mechanisms. Design of such QZS mechanisms, however, tends to be complex, and it is difficult to realize large loading capacity as well as large stroke length at the same time This paper attempts to resolve these issues by applying newly developed superelastic Cu-Al-Mn shape memory alloy (SMA) bars, characterized by excellent recoverable strain upon unloading along with small hysteresis and nearly flat stress plateau. These features are realized by material design tailored for obtaining mechanical properties required in QZS mechanisms. The use of such tailored superelastic Cu-Al-Mn SMA bars allows us to easily achieve large loading capacity as well as large stroke length while keeping the QZS mechanism simple and compact. In this paper, we derive design equations, produce a prototype, and conduct shaking table tests and numerical simulations to demonstrate the feasibility of QZS vibration isolator with superelastic Cu-Al-Mn SMA bars.
10.1016-j.jtice.2016.05.033	16	wear; composite; composites; powders; milling; particles; powder; wt; sliding; friction; hardness; matrix; mechanical; surface; properties	The trend toward renewable lubricant technology is now irreversible; an eco-friendly cutting fluid will go along with machining to achieve relative sustainability. Eco-friendly nanofluids are developed in this work and compared with traditional cutting fluids used for heat transfer. In this work, in-situ novel hybrid nanoparticles of Cu-Zn (50:50) alloy were synthesized. The stability of the hybrid nanofluids was carried out using photo capturing method and DLS method. The flash point was measured using Pensky-Martens open cup apparatus as per ASTM D6450. The thermal conductivity and rheological studies were carried out using KD-2 Pro and Rheometer. The results illustrate that the hybrid nanofluids exhibited stability for 72 h and then the agglomeration of particles starts and by 168 h almost all the particles tend to settle down. Nanofluids with vegetable oil as basefluid showed better increment in flash point, thermal conductivity and showed marginal less stability. Vegetable oil behaved as Newtonian fluid and the change in viscosity with application of shear was less noticed compared with other two fluids. On the basis of integrated study of thermal conductivity and viscosity, in the point of cost and higher relative thermal conductivity to relative viscosity for effective heat transfer vegetable oil based nanofluid showed better results.
10.1016-j.kjs.2023.07.011	-1		The electrical properties, hardness, and strength of the Zn-based ternary alloys were determined based on their microstructural properties. Formation and microstructural analyses were performed on Cu5Zn8, Al4Cu9, and Cu3Al intermetallic phases. When the electrical properties of the alloy were examined, it was seen that the electrical resistivity increased according to the amount of Cu. Electrical resistivity values were obtained in the range of 9.7216 x 10-8 -6.5881 x 10-7 omega m by DC four-point probe method (FPPM). The results obtained with the FPPM showed good electrical resistance, which can be applied to electronics as a lead-free soldering material. For each composition of Zn-Al-Cu alloys, the hardness value was measured within the range of 82.70-94.03 HV0.1, the ultimate tensile strength (UTS) was measured within the range of 133.48-202.56 MPa. In addition, yield strength (YS0.2) was measured within the range of 128.22-174.67 MPa. The results of our study are compatible with the expectation that the highest strength, yield strength, hardness etc. properties will be obtained in eutectic alloy systems.
10.1016-j.matchar.2003.11.002	16	wear; composite; composites; powders; milling; particles; powder; wt; sliding; friction; hardness; matrix; mechanical; surface; properties	In the present work, copper powder (purity-99.7%, grain size-63 mum maximum) was mechanically alloyed with lithium (purity>99%) in a SPEX ball mill. The alloying process was carried out for 15 h under an argon atmosphere using WC containers and stainless steel balls. The alloyed powders were then hot-consolidated by uniaxial hot pressing at different temperatures (300, 400, 500, and 550 degreesC) for 3 h at a pressure of 90 MPa, again under an argon atmosphere. The compacted samples were then characterized metallurgically, mechanically, and electrically; some of the properties (porosity, hardness, tensile strength, and electrical resistivity) are reported and analyzed in the present paper. The best results were obtained using a consolidation temperature of 400 degreesC-a condition which led to a microstructure showing low porosity, a hardness significantly higher than the other samples, and a tensile strength very similar to that for OFHC copper compacted in the same manner. The electrical resistivity was found to be small compared with that of other copper alloys used nowadays in large industrial applications.
10.1016-j.matchar.2004.12.010	6	grain; deformation; strain; strength; dislocation; cu-; tensile; size; ecap; grain size; sfe; ductility; hardening; high; stress	The influence of cold deformation by 50%, 75% and 90% on the age-hardening behavior of a Cu-3Ti-1Cd alloy has been investigated by hardness, tensile tests and light optical as well as transmission electron microscopy. The hardness of Cu-3Ti-1Cd alloy increased from 111 HV in the solution-treated condition to 355 HV in 90% cold worked and peak aged condition. The yield and ultimate tensile strengths of Cu-3Ti-1Cd alloy reached maxima of 922 MPa and 1035 MPa, respectively, on 90% deformation and peak aging. The microstructure of the deformed alloy exhibited elongated grains and deformation bands. The maximum strength on peak aging was brought about by the precipitation of ordered, metastable, coherent beta' Cu4Ti phase, in addition to high dislocation density and deformation twins. Both the hardness and the strength of the alloy decreased on overaging due to the development of the incoherent equilibrium phase beta Cu3Ti in a cellular structure form. However, the morphology of the discontinuous precipitation was changed to globular form at high deformation levels.
10.1016-j.matchar.2005.04.006	16	wear; composite; composites; powders; milling; particles; powder; wt; sliding; friction; hardness; matrix; mechanical; surface; properties	New copper-based composites are developed via powder metallurgy and strengthened through the dispersion of ceramics. The preparation of these alloys is carried out in two stages: (a) mechanical alloying (MA) in a planetary mill of high energy and (b) consolidation by hot uniaxial pressure followed by hot rolling. The behavior of the mechanical and electrical properties of these alloys associated to the inicrostructure changes will determine if the desired characteristics are achieved, for their use in electrical components. In the present study two copper-based alloys with 1% vol and 2% vol TiB2 were made by mechanical alloying over 12 h and 36 h . The resulting compacts consist mostly of equi-axed TiB2 grains homogeneously dispersed in a copper matrix with an average diameter of 0.6 mu m for the 36 It sample. The consolidated composites have an electrical conductivity of 31.4% IACS (International Annealed Copper Standard, 100% IACS=58 MS/m), a hardness of 78.7 HRb, and a tensile strength of 318 MPa as a minimum. Moreover, the TiB2 shows good stability at 923 K during hot consolidation.
10.1016-j.matchar.2006.02.017	6	grain; deformation; strain; strength; dislocation; cu-; tensile; size; ecap; grain size; sfe; ductility; hardening; high; stress	The influence of 50%, 75% and 90% cold work on the age hardening behavior of Cu-3Ti-1Cr alloy has been investigated by hardness and tensile tests, and light optical and transmission electron microscopy Hardness increased from 118 HV in the solution-treated condition to 373 HV after 90% cold work and peak aging. Cold deformation reduced the peak aging time and temperature of the alloy The yield strength and ultimate tensile strength reached a maximum of 1090 and 1110 MPa, respectively, following 90% deformation and peak aging. The microstructure of the deformed alloy exhibited elongated grains and deformation twins. The maximum strength on peak aging was obtained due to precipitation of the ordered, metastable and coherent beta'-Cu4Ti phase, in addition to high dislocation density and deformation twins. Over-aging resulted in decreases in hardness and strength due to the formation of incoherent and equilibrium beta-Cu3Ti phase in the form of a cellular structure. However, the morphology of the discontinuous precipitation changed to a globular form on high deformation. The mechanical properties of Cu-3Ti-1Cr alloy are superior to those of Cu-2.7Ti, Cu-3Ti-1Cd and the commercial Cu-0.5Be-2.5Co alloys in the cold-worked and peak-aged condition.
10.1016-j.matchar.2006.11.009	4	transformation; martensite; martensitic; phase; shape; beta; memory; shape memory; temperature; temperatures; martensitic transformation; gamma; transformation temperatures; effect; thermal	The effect of grain size on the pseudoelastic behaviour of a Cu-11.4 wt% Al-0.5 wt% Be shape memory alloy was studied. Annealing at 1073 K leads to grain growth with a kinetic exponent around 0.5. The martensite-start stress (sigma(s)), the pseudoelastic slope and the stress hysteresis decrease as the grain size increases. The effect of grain constraint on sigma(s) for CuAlBe is stronger than for other shape memory alloys but it is very weak on the pseudoelastic behaviour. Pseudoelastic cycling with increasing strain beyond 2% leads to a decrease in sigma(s) and an increase in the strain retained on unloading, due to increasing retention of the martensite phase on unloading. The important overheating needed for the transformation to beta phase indicates that the stress-induced martensite is effectively stabilized.
10.1016-j.matchar.2007.07.017	4	transformation; martensite; martensitic; phase; shape; beta; memory; shape memory; temperature; temperatures; martensitic transformation; gamma; transformation temperatures; effect; thermal	In Cu-11.92 wt%Al-3.78 wt%Ni shape memory alloy, the influence of deformation and thermal treatments on the microstructure and mechanical properties under the compression test were studied by means of scanning electron microscopy (SEM), transmission electron microscopy (TEM), and differential scanning calorimetry (DSC). Experiments show that the mechanical properties of the alloy can be enhanced by convenient heat treatments. The alloy exhibits good mechanical properties with high ultimate compression strength and ductility after annealing at high temperature. However, it exhibits brittle fracture and dramatic strain hardening, with linear stress-strain behavior after annealing at low temperature. The changes in the mechanical properties have been linked to the evolution of the degree of order, occurrence of precipitation, and variation of the grain size. From microstructural observations, it is seen that the beta(1)' (18R) and gamma(1)' (2H) martensite phases coexist at different fractions in the undeformed and deformed states. Deformation induces the changes between the beta(1)' and gamma(1)' martensites and deformation-induced martensites form at preferred orientations as mechanical twins. The beta(1)' martensite variants are twin-related with respect to the (128)(18R) mirror plane and a new orientation relationship for these twin variants is derived as (128)(A)parallel to (128)(C): [461](A)parallel to [461](C). Additionally, an increase in the amount of deformation causes martensite reorientation, de-twinning, and dislocation generation; also, the martensite plates are seen to have rearranged in the same orientation to be parallel with each other.
10.1016-j.matchar.2007.08.031	-1		Diffusion induced grain boundary migration (DIGM) has been studied in the Cu-Zn system by exposing polycrystalline Cu to Zn vapor with a Cu-38wt% Zn alloy as the source of Zn. The time and temperature dependence of the migration distance has been studied in the temperature range 350 to 600 C. The composition-distance profile was obtained along the thickness of the sheet specimen to determine the diffusivity, kD(b)delta at each temperature. Similarly, the quantity of Zn was determined behind the migrated grain boundary to calculate the coherency strain energy and the total chemical free energy change. It was observed that a part of the total free energy change was used for volume diffusion ahead of the migrating grain boundary. The effective free energy change was calculated and it was observed that the fraction of the total free energy change used for volume diffusion increased as the transformation temperature increased. A plot of instantaneous rate of migration vs. composition behind the grain boundary has indicated that the coherency strain energy acts as the driving force for DIGM. The fine-grained layer followed a parabolic growth behavior. The diffusion coefficients calculated from the thickness of the fine-grained layer are of the same order of magnitude as those calculated from the rate of migration of the grain boundary. The diffusivity as well as the activation energy calculated from the kD(b)delta vs. 1/T plot corresponds to that of grain boundary diffusion of Zn in Cu.
10.1016-j.matchar.2008.01.007	-1		Optical and transmission electron microscopy studies have been under-taken in order to clarify some morphological aspects of the discontinuous precipitation (DP) reaction in a Cu-15Ni-8Sn (wt%) alloy in the temperature range 800-950 K. The DP reaction proceeds in the ternary Cu-Ni-Sn system relatively fast (in binary Cu-Ni alloy is not present) with typical morphological features like change of growth direction, appearance and disappearance of solute-rich gamma lamellae. A fine continuous precipitation of single Ni and Sn-rich phase was also evidenced within the solute-depleted a lamellae. An energy-dispersive X-ray analysis showed the level of partitioning of the alloying elements. Most of the Ni and Sn is located in the gamma lamellae. However, the formula of the gamma lamellae is still close to (CU3Sn), which indicates that some Cu atoms are replaced by Ni.
10.1016-j.matchar.2008.02.002	-1		Digital image correlation was used to study the mechanical behavior of three materials: commercial aluminum, bovine pericardium and Cu-Al 11.2 wt%-Be 0.6 wt% shape memory alloy. These materials were subjected to simple tension test using an MTS load frame with an attached optical microscope. Displacement, force, strain data and digital images of the sample's surface were acquired. Data and images were post-processed in order to measure displacement vector fields for each material. Local and global strain measurements were calculated hence the young modulus was obtained for each material. The elastic moduli were 60 GPa for aluminum, 160 MPa for bovine pericardium and 110 GPa for the CuAlBe austenitic phase and 27 GPa for the mixture of austenite and martensitic phases.
10.1016-j.matchar.2008.03.001	4	transformation; martensite; martensitic; phase; shape; beta; memory; shape memory; temperature; temperatures; martensitic transformation; gamma; transformation temperatures; effect; thermal	The mechanical behavior and fracture characteristics resulting from thermal cycling treatments under different applied loads were investigated in a monocrystalline Cu-13.5 wt-%Al-4.0 wt%Ni alloy. The treatments consisted of 300 cycles in the temperature interval between 0 degrees C (close to M-f) and 100 degrees C (above A(f)), under applied load conditions of 0.2 and 0.5 kg corresponding, respectively, to stresses of 11 x 10(-2) and 28 x 10(-2) MPa. Following each treatment, the specimens were tested in compression until fracture at room temperature. In addition to the compression results, the mechanical behavior was also evaluated by microhardness tests. Structural changes related to phase transformations were characterized by X-ray diffraction and the fracture characteristics were analyzed by scanning electron microscopy. It was found that the thermal cycling treatments promote significant changes in the structure due to a reversible martensitic transformation. An increase in the applied load results in a decrease in both the pseudo-yield and the total strain. It also results in a lower fracture resistance owing to additional deformation accumulated during the cycling treatment, which provokes the reversible martensitic transformation.
10.1016-j.matchar.2008.09.014	-1		This study deals with the processing, microstructure, mechanical properties, electrical conductivity and wear behavior of high volume titanium carbide reinforced copper matrix composites. The microstructural study revealed that the titanium carbide particles were distributed uniformly in the matrix phase. No interface debonding and micro-cracks were observed in the composite. The addition of alloying elements in the copper considerably increased the sintered density and properties. The composite hardness and strength increased with titanium carbide content and alloying elements in the matrix phase, The electrical conductivities of the composites were predicted using three point upper bound and two phase self consistent predictive models. The wear resistance of the composites was studied against high speed steel. Wear mechanisms were discussed by means of microscope observations on the worn surfaces. The ratio of titanium carbide average grain size to the mean free path of the binder was introduced as a parameter to determine wear performance.
10.1016-j.matchar.2009.01.006	-1		A Cu-Al 11.2 wt%-Be 0.6 wt% shape memory alloy was subjected to a uniaxial tension test using an MTS load frame with an attached optical microscope. Digital images of the sample's surface were acquired using white light and He-Ne laser illumination. The obtained images were associated to the engineering stress-strain behavior, which was calculated from the measured displacement, strain and force. From the images, displacement vector fields were calculated for white light and laser illumination by digital image correlation (DIC) and digital speckle pattern correlation (DSPC) techniques respectively. Using white light it was possible to observe the grains and the martensitic phase transformation of the material more clearly than using DSPC; nevertheless, better quantitative results of displacement, in-plane strain and elastic moduli were obtained using DSPC than using DIC when they were compared to the reference values measured by electrical extensometry. Furthermore DIC and DSPC work as complementary techniques to determined the micro and macromechanical behavior of the CuAlBe shape memory alloy.
10.1016-j.matchar.2009.05.001	-1		In order to produce a W-25%Cu nanocomposite powder manufactured by a thermochemical procedure a novel pair of precursors were used. Cu2WO4(OH)(2) and CuWO4 center dot 2H(2)O precipitates were first produced by reacting the copper nitrate and sodium tungstate aqueous solutions under certain pH and temperature. The precipitates were then dried and calcined in order to prepare CuWO4-x, CuO, and WO3 oxide powders for the next step reduction. The reduction was carried out under a H-2 atmosphere to form the final W-Cu metal nanocomposite powder. Characteristics of the final powder such as distribution, uniformity and size were then discussed based thoroughly on the dominant mechanism of reduction; Chemical Vapor Transport. It was found that the average particle size of the reduced powder is 35 nm for W and 54 nm for Cu.
10.1016-j.matchar.2010.02.008	4	transformation; martensite; martensitic; phase; shape; beta; memory; shape memory; temperature; temperatures; martensitic transformation; gamma; transformation temperatures; effect; thermal	Continuous and pulsed electromagnetic radiation was used to detect the self-accommodation mechanism on a polycrystalline Cu-13.83 wt%Al-2.34 wt%Ni shape memory alloy. Rectangular samples of this alloy were mechanically polished to observe the austenite and martensite phases. The samples were cooled in liquid nitrogen prior to the experiments to obtain the martensite phase. Using a dynamic speckle technique with a continuous wave laser we obtained the time history of the speckle pattern image and monitored the surface changes caused by the self-accommodation mechanism during the inverse (martensitic to austenitic) transformation. Using a photoacoustic technique based on a pulsed laser source it was also possible to detect the self-accommodation phenomena in a bulk sample. For comparison purposes, we used differential scanning calorimetry (DSC) to detect the critical temperatures of transformation and use these as reference to evaluate the performance of the optical and photoacoustical techniques. In all cases, the same range of temperature was obtained during the inverse transformation. From these results, we conclude that time history speckle pattern (THSP) and pulsed photoacoustic are complementary techniques; they are non-destructive and useful to detect surface and bulk martensitic transformation induced by a temperature change.
10.1016-j.matchar.2010.11.014	-1		Scanning and transmission electron microscopy examinations of Cu-24.5at% Al-19.4at% Mn (similar to Cu(2.2)Mn(0.8)Al) alloy were performed after aging at temperatures ranging from 350 degrees C to 700 degrees C for various durations. It was observed that only gamma-brass type and L-J phases were formed after aging at or below 400 degrees C. On the other hand, the beta-Mn phase was formed after aging at temperatures ranging from 500 degrees C to 650 degrees C. It is noteworthy that the precipitation behaviors of the,gamma-brass type and beta-Mn phases are different at different aging temperatures. This remarkable result differs from those reported in previous studies on the Cu(3-x)Mn(x)Al alloys with X <= 1.
10.1016-j.matchar.2012.11.007	4	transformation; martensite; martensitic; phase; shape; beta; memory; shape memory; temperature; temperatures; martensitic transformation; gamma; transformation temperatures; effect; thermal	The investigation of thermal, mechanical and magnetic behaviors of the Cu-11%Al, Cu-11%Al-3%Ag, Cu-11%Al-10%Mn and Cu-11%Al-10%Mn-3%Ag alloys was made using microhardness measurements, differential scanning calorimetry, X-ray diffractometry, scanning electron microscopy, energy dispersion X-ray spectroscopy and magnetic moment change with applied field measurement. The results indicated that the Mn addition changes the phase stability range, the microhardness values and makes undetectable the eutectoid reaction in annealed Cu-11%Al and Cu-11%Al-3%Ag alloys while the presence of Ag does not modify the phase transformation sequence neither microhardness values of the annealed Cu-11%Al and Cu-11%Al-10%Mn alloys, but it increases the magnetic moment of this latter at about 2.7 times and decreases the rates of eutectoid and peritectoid reactions of the former.
10.1016-j.matchar.2013.03.010	4	transformation; martensite; martensitic; phase; shape; beta; memory; shape memory; temperature; temperatures; martensitic transformation; gamma; transformation temperatures; effect; thermal	In this work, the effects of Be addition on the microstructure and phase transformation temperatures of Cu-12Al-xBe (x = 0.4, 0.5 and 0.6 wt%) shape memory alloys fabricated by using the arc-melting and melt-spinning techniques have been investigated. X-ray diffraction analysis revealed that the arc-melted alloys consisted of austenitic beta(1), martensitic beta(1)' and gamma(2) precipitate phases, whereas melt-spun ribbons were composed of a fully martensitic phase. The average grain size of martensitic phases in melt-spun ribbons was determined by electron microscopy images, showing a decrease with increasing Beryllium (Be) amount. Moreover, it was found that the Be addition in the arc-melted alloys had a distinct effect on the morphology of the gamma(2) precipitate phase. Transmission electron microscopy analysis showed that the thickness of martensitic plates in the melt-spun ribbons reduced with increasing Be addition. In a differential scanning calorimeter analysis, no martensitic transformation (M-s) peak was observed in arc-melted alloys, but it was clearly detected in melt-spun ribbons, in which M-s decreased dramatically with increasing Be addition. The improvement in the shape memory ability of melt-spun ribbons was explained in terms of the refinement in grain size and martensitic plates.
10.1016-j.matchar.2014.01.006	-1		An age-hardenable Cu-2.9%Ni-0.6%Si alloy was subjected to high-pressure torsion. Aging behavior was investigated in terms of hardness, electrical conductivity and microstructural features. Transmission electron microscopy showed that the grain size is refined to similar to 150 nm and the Vickers microhardness was significantly increased through the HPT processing. Aging treatment of the HPT-processed alloy led to a further increase in the hardness. Electrical conductivity is also improved with the aging treatment. It was confirmed that the simultaneous strengthening by grain refinement and fine precipitation is achieved while maintaining high electrical conductivity. Three dimensional atom probe analysis including high-resolution transmission electron microscopy revealed that nanosized precipitates having compositions of a metastable Cu3Ni5Si2 phase and a stable NiSi phase were formed in the Cu matrix by aging of the HPT-processed samples and these particles are responsible for the additional increase in strength after the HPT processing. (c) 2014 The Authors. Published by Elsevier Inc.
10.1016-j.matchar.2014.07.014	-1		The present work is devoted to an investigation of the formation kinetics, stability and homogeneity area of the nanoscale icosahedral phase formed on heating in the dual-phase glassy/quasicrystalline phase Cu-Zr-Ti-Pd alloys. The data obtained indicate that the Cu-Zr-Ti-Pd icosahedral phase is not a Cu-rich part of the compositional homogeneity area of the Zr-Cu-Pd one. Moreover, Ti, as well as Pd, is found to be an important element stabilizing quasicrystalline phase in the Cu-Zr-Ti-Pd alloys. The formation criteria for Cu- and Zr/Hf-based icosahedral phases are discussed based on the quasilattice constant to average atomic diameter ratio. Deviation from a certain ratio leads to destabilization of the icosahedral phase. By using the isothermal calorimetry traces transformation kinetics above and below the glass-transition region was analyzed. Some difference in the transformation kinetics above and below the glass-transition region allows us to suggest that possible structure changes occur upon glass-transition.
10.1016-j.matchar.2014.12.022	-1		A Cu-Co composite material is chosen as a model system to study structural evolution and phase formations during severe plastic deformation. The evolving microstructures as a function of the applied strain were characterized at the micro-, nano-, and atomic scale-levels by combining scanning electron microscopy and transmission electron microscopy including energy-filtered transmission electron microscopy and electron energy-loss spectroscopy. The amount of intermixing between the two phases at different strains was examined at the atomic scale using atom probe tomography as complimentary method. It is shown that Co particles are dissolved in the Cu matrix during severe plastic deformation to a remarkable extent and their size, number, and volume fraction were quantitatively determined during the deformation process. From the results, it can be concluded that supersaturated solid solutions up to 26 at% Co in a fcc Cu-26 at% Co alloy are obtained during deformation. However, the distribution of Co was found to be inhomogeneous even at the highest degree of investigated strain. (C) 2014 The Authors. Published by Elsevier Inc.
10.1016-j.matchar.2015.03.021	-1		Cu-Al alloys with Al contents of 1, 2, 4, and 6 wt% were deformed using a multi-axial compression (MAC) technique to obtain ultrafine-grained (UFG) and nanocrystalline (NC) structures. The effects of stacking fault energy (SFE) on the microstructural evolution and mechanical properties were investigated. After multiple MAC passes, homogeneous and equilibrium microstructures were achieved. The grain refinement mechanism mainly consists of conventional dislocation subdivisions, twinning and shear banding. Reducing SFE promotes deformation twinning and shear banding and thus can reduce the final equilibrium grain size. After obtaining UFG/NG Cu-Al alloys (<200 nm), further deformation results in different microstructures for four Cu-Al alloys, indicating that a transition from de-twinning dominant mechanism to twinning dominant mechanism exists in UFG/NG Cu-Al alloys, occurring at a critical SFE in the range of 25 mJ m(-2) (2 wt% Al) and 13 mJ m(-2) (4 wt% Al). During deformation, the migration mechanism of dissociated incoherent twin boundaries (ITBs) was analyzed and the motion of ITBs was believed to be a way for twinning or de-twinning. In addition, hardness tests indicate that with increasing the strain the micro-Vickers hardness for the four alloys increased dramatically initially and then reached saturation at a relative stable value with further increasing the strain. The study suggests that gentle-MAC processing (at a low strain rate and room temperature) is a relative effective method to produce nano-grained materials (<100 nm) with ultra-low-SFE (<10 mJ m(-2)).
10.1016-j.matchar.2015.09.009	-1		Sintering of the Cu nanopartide at low temperatures resulted in exothermic behavior after its initiation. The calorimetry study of the heating of a 20 nm copper nanoparticles agglomerate revealed the evolution of 41.17 J/g of heat between 170 degrees C and 270 degrees C. High resolution transmission electron microscopy (HRTEM) images indicated that the heat generation was accompanied by sintering. The surface energy of the 20 nm copper nanopartides was estimated to be 1.23 x 10(3) erg/cm(2) based on the heat released during sintering. The in situ high resolution transmission electron microscope (HRTEM) investigation showed that vigorous sintering occurred between 217 and 234 degrees C, which took place through the dislocation sintering mechanism.
10.1016-j.matchar.2016.01.004	-1		The crystallographic features of iron-rich nanoparticles in Cu-10Sn-2Zn-1.5Fe-0.5Co (wt%) alloy fabricated by centrifugal casting were investigated. Near-spherical and ear-like iron-rich nanoparticles were both observed. Analysis of electron diffraction patterns and Moire fringes of iron-rich nanoparticles showed the coexistence of several crystal structures and orientation relationships (OR). Most of the near-spherical nanoparticles with 2-20 nm in diameter possess face-centered cubic (f.c.c.) structure with cube-on-cube OR with Cu matrix. The near-spherical nanoparticles (2-20 nm) possessing body-centered cubic (b.c.c.) structure with Kurdjumov-Sachs (K-S) OR also exist. Moire fringes were observed in such nanoparticle, which exhibits the ((3) over bar1 (1) over bar)(cu) facet plane contrary to the previous research . Ordered b.c.c. iron-rich nanoparticle with Nishiyama-Wassermann l=(K-S) OR characterized by a periodic array of distinguished striations perpendicular to the [(1) over bar 10], direction was detected. Ear-like iron-rich nanoparticles (20-150 nm) were identified as f.c.c structure. Furthermore, the formation mechanism of ear-like iron-rich nanoparticle was elucidated.
10.1016-j.matchar.2016.03.008	-1		We report the influence of the microstructure on the martensitic transformation in polycrystalline Cu-Zn-Al thin films with 18R structure. The films are grown in two steps. First, Cu-Al thin films are obtained by DC sputtering. Second, the Zn is introduced in the Cu-Al thin films by the annealing them together with a bulk Cu-Zn-Al reference. The crystalline structure of the films was analyzed by X-ray diffraction and transmission electron microscopy. The martensitic transformation temperature was measured by electrical transport using conventional four probe geometry. It was observed that temperatures above 973 K are necessary for zincification of the samples to occur. The resulting martensitic transformation and its hysteresis (barrier for the transformation) depend on the grain size, topology and films thickness.
10.1016-j.matchar.2016.08.023	-1		A copper-based composite with a distribution of face-centered cubic (FCC), body-centered cubic (BCC) and martensite structured Fe-C particles has been developed, and most of FCC structured particles can be phase transformed into BCC or martensite structured particles after cold rolling at room and low temperatures, and the fraction of martensitic transformation increases as the deformation temperature is lowered. The martensitic transformation can significantly improve both the strengths and deformability of copper-based composite. A ductile fracture is still the main tensile fracture characteristic for the composite even in the cold rolling conditions. Accordingly, a cooperative deformation model was put forward in this paper. (C ) 2016 Elsevier Inc. All rights reserved.
10.1016-j.matchar.2016.10.006	-1		The crystallographic texture, micro-hardness and magnetic property have been investigated in Cu-57 at% Ni, Cu-53 at% Ni, and Cu-49 at% Ni alloy used as substrates for coated conductors. In this work, a similar rolling texture was observed in the cold rolled condition for the three alloys. For each material, annealing at higher temperature results in a much stronger cube texture but the fraction of annealing twin boundary was quiet low. When annealing at 700 degrees C and 800 degrees C, it was presumed that the increase of Cu element increased grain boundary mobility, which then lead to the enhancement of twin boundary and weakened the cube texture. In addition, magnetization measurements indicate that the increase of Cu content can effectively reduce the saturation magnetization in Cu-Ni alloys. The comparatively low ferromagnetism for both Cu-53 at% Ni and Cu-49 at% Ni alloys suggests that substrates produced using these materials will benefit from decreasing hysteresis losses for alternating current applications.
10.1016-j.matchar.2016.10.009	6	grain; deformation; strain; strength; dislocation; cu-; tensile; size; ecap; grain size; sfe; ductility; hardening; high; stress	Ultrafine-grained (UFG) Cu with uniform microstructure was successfully prepared by friction stir processing (FSP) under additional water cooling. FSP Cu exhibited equiaxed grains with low dislocation density, weak texture, and high fraction of high-angle grain boundaries. Isotropy and tension-compression symmetry were achieved in FSP Cu sample, which provided an ideal model material to investigate the intrinsic mechanical behavior of the UFG material. Enhanced strain hardening was achieved in FSP Cu due to the special microstructure which was effective in accumulating dislocations, resulting in good strength-ductility synergy. This study provides a feasible strategy of preparing bulk UFG materials with good mechanical properties.
10.1016-j.matchar.2017.01.027	-1		An innovative hybrid process combining two very effective solid-state techniques which are Cold Spray (CS) and Friction Stir Processing (FSP), was proposed to fabricate a high-strength ultrafine-grained Cu-Zn coating. Results show that the cold-sprayed coating obtained exhibits an elongated microstructure with 78.42% of low-angle grain boundaries. Following FSP, there appear ultrafine grains with 90.47% of high-angle grain boundaries and a blend of alpha,beta '' and gamma phases, while the as-sprayed coating is mainly alpha-phased. Significant mechanical properties enhancement is achieved, i.e. with the ultimate tensile strength increasing from 87.2 MPa to 257.5 MPa and the fracture elongation increasing from 0.17% to 0.81%. The precipitates have a significant effect on the fracture behavior of friction-stirred coating.
10.1016-j.matchar.2017.04.004	-1		Nanocrystalline Cu-14 at% Al alloy was synthesised by cryomilling. Milled powder was then annealed up to T/T-m = 0.87 and corresponding changes in grain size (by X-ray peak broadening analysis) and hardness values were recorded. The hardness of the milled powder (3.28 GPa) decreases only 17% (2.73 GPa) after annealing at T/T-m, = 0.87. The improved thermal stability was attributed to the dispersion of nanoscale intermetallic (CuAl2) phase, observed by Transmission electron microscopy (TEM) investigation of the annealed samples. The closure agreement of theoretically estimated mechanical property (hardness) with the experimentally obtained one elicits kinetic stabilisation (i.e. grain boundary pinning by intermetallic particles) is the governing strengthening mode at high temperatures.
10.1016-j.matchar.2017.04.026	6	grain; deformation; strain; strength; dislocation; cu-; tensile; size; ecap; grain size; sfe; ductility; hardening; high; stress	The cold rolled Cu-2.7Be sheets were annealed at different temperatures. The evolution of microstructure, texture and tensile properties was investigated using electron backscatter diffraction (EBSD), transmission electron microscopy (TEM) and tensile tests, respectively. Results showed that preponderant Sigma 3 annealing twins were produced during recrystallization. The Sigma 3 fraction and average grain size increased with increasing annealing temperature. Besides, it turned out that the extension and depletion of twin bouridaries occurred simultaneously during grain growth process, affecting the Sigma 3 fraction. Recrystallization texture became relative isotropic because of twinning mechanism which involved the formation of new orientations from the parent grain. It was noteworthy that the weak recrystallization cube texture was observed, which was attributed to appearance of preponderant twin boundaries. Tensile tests results showed that twin boundaries should be considered as effective obstacles to dislocations motion, similar to regular grain boundaries.
10.1016-j.matchar.2017.10.030	6	grain; deformation; strain; strength; dislocation; cu-; tensile; size; ecap; grain size; sfe; ductility; hardening; high; stress	Ultrafine-grained (UFG) oxygen free high conductivity (OFHC) Cu samples were processed by severe plastic deformation (SPD) using the method of equal channel angular rolling (ECAR) up to 33 passes at room temperature. It was found that the grain size gradually decreased from similar to 40 mu m to similar to 250 nm with increasing the number of passes. A maximum dislocation density of similar to 21 x 10(14) m(-2) was achieved after 13 passes of ECAR. For large numbers of passes (between 23 and 33), the dislocation density decreased to similar to 14 x 10(14) m(-2). The proof stress was saturated at the value of about 400 MPa. The stored energy was measured by calorimetry and compared with the values calculated from the parameters of the microstructure. The reduction of the released heat after 13 and 33 passes suggested structural relaxation of the UFG microstructure. For these numbers of passes, the reduction of area in tensile testing was improved without decreasing the proof stress. The correlation between the microstructure and the mechanical behavior was discussed in detail. It was found that ECAR is capable for the mass-production of UFG metallic materials with high strength, therefore this method is a possible way of commercialization of SPD-processed materials.
10.1016-j.matchar.2017.11.006	6	grain; deformation; strain; strength; dislocation; cu-; tensile; size; ecap; grain size; sfe; ductility; hardening; high; stress	Microstructure changes of ultrafine-grained pure copper prepared by equal-channel angular pressing were investigated during in situ tensile testing inside a scanning electron microscope at constant total strain rate of 10(-4) s(-1) at 373 K (similar to 0.28 T-m). After fast work hardening the flow stress saturated at an inelastic strain of 0.06. Significant local coarsening of grains was observed to start at about 2/3 of the maximum flow stress. However, these localized events did not significantly change the mean grain size up to an inelastic strain of 0.09. Surface observations showed that the coarsening was preferentially located at shear bands.
10.1016-j.matchar.2017.11.024	6	grain; deformation; strain; strength; dislocation; cu-; tensile; size; ecap; grain size; sfe; ductility; hardening; high; stress	The aim of the present study is to investigate the effect of short-range order (SRO) on the microstructural evolution and mechanical property of Cu-10 at%Mn alloy during cold drawing deformation. Characterization of the cold drawn Cu-10 at%Mn alloy samples were performed using transmission electron microscope (TEM) and electron back scattering diffraction (EBSD), and their hardness were also tested. The results show that SRO is beneficial for both twinning and the transition of dislocation glide from wavy slip to planar slip at the low strains. At the high strains, the wavy slip generates due to the destruction of SRO. SRO increases the volume fraction of < 111 > texture component and the critical strain threshold. Moreover, the presence of SRO significantly improves strain hardening by combining the effects of dislocation, deformation twinning and texture hardening, which results in a significant increase of hardness.
10.1016-j.matchar.2018.03.025	4	transformation; martensite; martensitic; phase; shape; beta; memory; shape memory; temperature; temperatures; martensitic transformation; gamma; transformation temperatures; effect; thermal	We report the recrystallization of metastable hexagonal and body centered cubic BCC phase in free-standing 6 pm thick Cu-Al-Ni films grown by DC sputtering at room temperature. The results show that the BCC phase recrystallizes to L2(1) at around 533 K together with precipitation of gamma(2)-phase. Annealing temperatures (533 K-623 K) at short times (0-30 min) produce systematic increment of the fraction of gamma(2)-phase. Films with phase coexistence of hexagonal, gamma(2) and L2(1) structure display temperature driven martensitic transformation. This transformation is observed for samples with austenite grain size of around 30 nm. In all cases, the martensitic transformation temperature (M-s) notoriously decreases (compared to bulk) and systematically increases with the annealing temperatures and annealing time. In addition, the films display extended transformation and retransformation ranges along with asymmetric hysteresis, which may be associated to restitutive forces due to elastic deformations at martensite martensite and martensite austenite interfaces. Annealing temperatures above 623 K produce fast precipitation to equilibrium alpha- and gamma(2)-phases. The austenitic phase can be recovered after annealing over 1000 K and fast quenching in ice-water.
10.1016-j.matchar.2018.04.036	13	clusters; atomic; glass; atoms; composition; dynamics; metallic; icosahedral; glasses; simulations; molecular; cu-zr; molecular dynamics; metallic glasses; structural	Atomic structures of Cu100-xZrx (x = 41.18-66.67) metallic glasses were investigated by extended X-ray absorption fine structure (EXAFS) spectroscopy and molecular dynamics (MD) simulations. It is demonstrated that both the fraction and average volume of the typical atomic clusters, characterized by Voronoi cells, are of compositional dependence. With the increasing of Zr content, the fraction of Cu and Zr centered Voronoi clusters with coordination number lower than 11 and 14 respectively increases, while that of clusters with larger coordination numbers reduces. Among the major Voronoi clusters, the Cu-centered icosahedra are distinctive. Their average volume is far smaller than that of the other Cu-centered Voronoi cells with the same coordination number. More importantly, they prefer to interlink into pentagon-rich icosahedral super-clusters. However, compared with their neighbors, the glasses with x = 44 and x = 50 exhibit no other particularity in Cu-centered icosahedra than a slightly enhanced interlink at x = 50 although glass forming ability (GFA) reaches a local maximum at these two compositions, indicating that there are other factors dominating the GFA change with composition. A significant reduction in free volume for the loosely packed regions takes place at x = 44 and x = 50, due to which the corresponding Cu-Zr metallic glasses have the maximum microhardness.
10.1016-j.matchar.2018.05.001	-1		TiC-strengthened Cu alloys with various nominal compositions were prepared by a high-energy ball-milling process, followed by consolidation using spark plasma sintering (SPS), and a subsequent heat treatment. The results indicated that the lower atomic ratio of C/Ti, the more residual Ti in copper matrix, resulting in a lower electrical conductivity but higher microhardness of alloy. The optimal atomic ratio was found to be close to1.0. The reaction behavior of Ti-C in the Cu-Ti-C system during this process was investigated. Microstructural results suggested that TiC formation is through a diffusion-controlled mechanism. A thin TiC layer was formed at the surface of C particles, and the growth of TiC layer was controlled by interdiffusion of C and Ti atoms across the TiC layer. An incomplete chemical reaction between Ti and C, characterized by a core-shell structure, was observed when the initial C particles were large, and the TiC particle size was found to strongly depending on the C particle size.
10.1016-j.matchar.2018.05.021	-1		In nanocrystalline metals, the formation of deformation twins is more likely through either random activation of partials (RAP) or cooperative slip of three partials (CSTP), which produces zero macroscopic strain. In their coarse-grained counterparts, deformation twins produce a net macroscopic strain and change the grain shape. Here, we report the formation of large scaled zero-strain deformation twins in coarse-grained Cu-Al alloys. The results showed that the split length of 9R phase dissociated from zero-strain deformation twins was affected significantly by the stacking fault energy. A higher stacking fault energy results in a longer split length of 9R phase.
10.1016-j.matchar.2018.07.016	-1		W-based alloys are currently considered promising candidates for high heat flux components in future fusion reactors. In this paper, hot pressed W-20 wt%Cu composites were treated at room temperature using a sliding friction severe deformation (SFD) process, with a moving speed of 0.2 m/s and an applied load of 500 N. Microstructural evolution of composites after the SFD treatment was evaluated and compared with that of the untreated composites. Results showed that there was a gradient structure generated and an obvious refinement in tungsten particles size in the surface layer after the SFD process. The average particle size of tungsten in the SFD treated composites was 2.60 pm, whereas it was 4.5 pm for tungsten in the untreated composites. Fracture surfaces of the composites indicated that the SFD treatment destroyed the W skeleton and changed fracture mode from predominant inter-granular one to trans-granular one due to the decrease in contact area of W-W inter particles. Yield strength and ultimate tensile strength of composites after the SFD treatment were 308 MPa and 553 MPa, respectively. The treated composites exhibited micro-hardness values with an average reading of about 308 HV. Analysis of the facture microstructures clearly suggested that the tungsten particles in the treated composites are consisted of dislocations and boundaries as well as dislocation tangles. The electrical conductivity of the composites was decreased from 33 %IACS to 28.5 %IACS after the SFD treatment, mainly due to loss or squeezing of copper into the inner surface.
10.1016-j.matchar.2018.08.015	-1		Electron back scatter diffraction pattern (EBSD), metallographic microscope (OM) and transmission electron microscope (TEM) are used to analyze the microstructural state of the Cu-Sn alloy before and after power spinning and annealing. The results show that after power spinning, the a phase grains are refined and gradually evolve into small and fine an and deformed am crystal grains, with an average grain size of about 2.2 mu m. Work hardening results in massive network-like subgrain boundaries distributed in power spinning microstructure. Annealing at 400 degrees C contributes to the formation of dislocation cells and stacking faults, and high-angle grain boundaries (HABS) start to migrate and slide. After the formation of less defective equiaxed grains at 500 degrees C, twins continue to grow and widen based through continuous accumulation of stacking faults. Further testing of mechanical properties reveals that power spinning is conducive to the improvement of mechanical properties of Cu-Sn alloy.
10.1016-j.matchar.2018.09.001	-1		We conducted high-pressure torsion (HPT) of hybrid materials composed of two copper disks with a layer of ZnO ceramic nanoparticles sandwiched in-between. A detailed microstructural analysis of the processed samples revealed a surprisingly high level of plastic deformation introduced in individual ZnO particles, even though they possess a much high hardness than the surrounding Cu. Moreover, we demonstrated that by tailoring the initial geometry of the system (i.e. introducing holes in the cladding Cu disks), we can effectively change the flow mode of ZnO particle clusters from laminar to turbulent one and facilitate their deagglomeration process. Finally, the presence of ZnO particles decreased the microstructural stability of the Cu matrix. We discussed the obtained results in terms of hydrodynamic and microstructural instabilities during plastic deformation. This work expands our understandings of the cooperative severe plastic deformation of two dissimilar materials and sheds new light on the design of hybrid materials.
10.1016-j.matchar.2018.09.002	1	shape; memory; shape memory; damping; martensite; martensitic; damping capacity; transformation; capacity; strain; superelasticity; temperature; cu-al-mn; shape memory effect; effect	The present paper aims to suppress the heating rate-dependent martensitic stabilization of ductile Cu-Al-Mn shape memory alloys through restricting the mobility and thus the behavior of vacancies. A combined study based on first-principles calculation and experimental results were presented to unveil the effect of Ni addition into ternary Cu-Al-Mn alloys on the bonding force between atoms. The results showed that additional nearest neighbor bond between Ni and Al atoms in quaternary Cu-Al-Mn-Ni alloys can be produced. The addition of Ni (<= 2 at%) into ternary Cu-Al-Mn alloys can not only efficiently increase the shape memory effect, but also suppress the occurrence of heating rate-dependent martensitic stabilization. The addition of 2 at% Ni improved the shape memory effect of ternary Cu-Al-Mn alloys from 85% to 92% when heated at 20 k/min. The shape memory effect of ternary Cu-Al-Mn alloys dropped to 10% as the heating rate decreased to 1 K/min, but it remain at 92% even when the heating rate was sufficiently lowered to 0.01 K/min after the addition of 2 at% Ni.
10.1016-j.matchar.2018.09.017	-1		The present work aims at identifying the evolution of the microstructure of a Cu-Ni-Si (Corson alloy) alloy after low cycle fatigue by means of advanced electron microscopy analysis techniques (SEM-ECCI, Orientation Imaging Microscopy by means of SEM-EBSD and TEM). Deep attention is paid on the material subjected to high cyclic strains where a transient cellular dislocation structure transformed into precipitate free bands. It is shown that the formation of dislocation cells leads to a high GROD and high GOSaera value and its standard deviation. However, the presence of precipitate free bands results in the low GOSarea level and its low standard deviation.
10.1016-j.matchar.2018.11.013	-1		The dislocation strengthening effect is generally considered to be controlled by dislocation density; however, in the present study the dislocation substructure is shown to play an even more important role for Cu-20Ni-20Mn alloy. The hardness and microstructural evolution during annealing in a hot-forged Cu-20Ni-20Mn alloy are investigated. Microstructure analysis of annealed samples indicated variation in the number of dislocations and dislocation substructure related to softening of the Cu-20Ni-20Mn alloy during static recovery. The tangled dislocations formed a regular array during annealing at 600 degrees C, leading to a high softening fraction of 95%. In addition, rapid dislocation annihilation and sub-boundary disintegration occurred during annealing owing to the dislocation climb at 650 degrees C. The number of mobile dislocations within the grains decreased considerably, leading to softening in the Cu-20Ni-20Mn alloy annealed at 650 degrees C.
10.1016-j.matchar.2018.11.018	15	aging; strength; conductivity; electrical conductivity; electrical; mpa; treatment; strengthening; degrees; cu-; cold; precipitation; tensile strength; tensile; iacs	Cu-6.0 Ni-1.0 Si-0.5 Al (wt%) alloy was fabricated, and its phase transformation behavior in the early stages of aging treatment were studied systematically, including the mechanical properties, type of precipitates, formation heat of precipitates, elastic strain energy, crystal orientation relationships, and spatial distribution of elements. The experimental results demonstrate that a B2 ordering structured j3-NiAl precipitate formed in the matrix as the supersaturation solid solution (SSS) was aged at 400 degrees C; 8-Ni2Si, a L1(2) ordering structured beta-Ni3Si, and L1(2) structured gamma'-Ni3Al were precipitated from the matrix aged at 450 degrees C; and discontinuous delta-Ni2Si precipitates occurred in the matrix aged at 500 degrees C and above. Atom probe results revealed that Ni and Si formed clusters with a size of 1-2 nm, and Al tended to segregate around these clusters as the SSS was aged at 450 degrees C. The ultimate tensile strength of the studied alloy was 1080.2 +/- 20.4 MPa for the sample aged at 450 degrees C for 1 h, and the electrical conductivity was 25.4% IACS. Sketch maps of the crystal orientation relationships between the matrix and precipitates were also established.
10.1016-j.matchar.2018.12.017	-1		The paper presents mechanical characteristics of the symmetric and asymmetric rolling processes as well as microstructure and material modifications of asymmetrically rolled polycrystalline copper. Mechanical aspects of the rolling process were examined experimentally and studied using the Finite Element Method. It was confirmed that the rolling normal force is reduced and distribution of torques between two work rolls are strongly modified in asymmetric rolling process, as compared with the symmetric one. The microstructure characteristics of asymmetrically rolled polycrystalline copper were examined using the EBSD technique, optical metallography and X-ray diffraction. It was found that asymmetric rolling leads to a grain refinement, an important modification of selected microstructure parameters, a slight modification of mechanical characteristics, a texture rotation around transverse direction and a homogenization of the shear strain and texture. It has to be underlined that an important contribution of the present work consists in a detailed study of the mechanical characteristics, related with material microstructure examination, for asymmetric and symmetric rolling processes. Experimental determination of the rolling normal force and distribution of torques between two work rolls is accompanied by theoretical predictions. Another interesting result is that microstructure modifications depend not only on the asymmetry ratio, but also on the way of inducing rolling asymmetry (modification of rolling gap geometry in the present case case).
10.1016-j.matchar.2019.01.027	-1		The texture transition Cu {112}< 011 > -> S3 {123}< 634 >, untypical for the coarse-grained state, is discovered during the flat rolling of the ultrafine-grained (UFG) Cu-10 wt%Zn alloy. This fact is the evidence of a change in the deformation mechanisms which are related to the features of the UFG state produced by severe plastic deformation. Modeling in the framework of the viscoplastic self-consistent model enables establishing that such a transition is possible due to the suppression of the activity of the {110}< 110 > slip systems and the {112}< 010 > twinning systems with increasing reduction ratio. The main contribution is made by the octahedral slip via the {111}< 010 > systems.
10.1016-j.matchar.2019.04.034	-1		For most ultrafine-grained metals, the yield stress increases with finer grain size, but the thermal stability reduces. In this study, high purity (99.999%) copper sheets were fabricated using three different techniques: symmetric rolling, asymmetric rolling and asymmetric cryorolling. In each case, the sheets were annealed at a temperature ranging from 50 degrees C to 125 degrees C for 1 h . Their mechanical properties were tensile-tested using dog-bone samples, and their microstructure evolution was examined using electron backscatter diffraction and transmission electron microscopy. The results show that the asymmetric-cryorolled copper sheets have finer grains and higher tensile strength, and better thermal stability compared with the copper sheets subjected to symmetric rolling and asymmetric rolling and low-temperature annealing. The finer grains in copper sheets subjected to asymmetric cryorolling result from the additional shear strain and severe plastic deformation at low temperature. The improvement in the thermal stability may be due mainly to the vacancy clusters, small laminate thickness, low-angle grain boundary and high misorientation angle in asymmetric cryorolled samples. These results can provide significant insights into the development of ultrafine-grained metal sheets with both excellent mechanical properties and high thermal stability.
10.1016-j.matchar.2019.05.026	-1		The Cu-11.9Al-2.5Mn (wt%) shape memory alloy (SMA) refined by the Cu51Zr14 inoculant exhibits special corrosion behavior in electropolishing process, which makes the surface of the alloy look like a beautiful ink-washing painting. Transmission electron microscope (TEM) observation reveals that this can be ascribed to the stress layers existing near the Cu51Zr14/Cu-Al-Mn interfaces. Fortunately, these stress layers do not disturb the perfect lattice matching relationship between the Cu51Zr14 particle and the Cu-Al-Mn SMA. This study provides a simple and efficient method to pursue the distribution of inoculant particles in the refined alloys and to help us to reveal the refining mechanism.
10.1016-j.matchar.2019.06.017	-1		Ultrafine grained Cu-4.5 vol% Al2O3 bulk composite samples were fabricated by a novel way involving three steps: (i) dealloying of a Cu-50wt%Al alloy powder to produce a nanocrystalline Cu-0.8wt%Al-1.5wt%O powder; (ii) heat treatment of the as-dealloyed powder using two different routes to obtain Cu-Al2O3 composite powders with Al2O3 particles distributed either at Cu grain boundaries or within Cu grains, and (iii) consolidation of the powders by powder compact extrusion. The microstructures, mechanical properties and electrical conductivity of the composite samples were investigated. The composite sample with a dispersion of intragranular Al2O3 nanoparticles exhibited an excellent combination of a high tensile strength (522 MPa), good ductility (elongation to fracture: 8.2%) and a high electrical conductivity (90%IACS). The correlation among the microstructure, mechanical properties and electrical conductivity is discussed.
10.1016-j.matchar.2019.109849	-1		The focus of researchers studying severe plastic deformation on the final grain size of material is often preventing them from observing a much wider spectrum of alterations to material defect structure. It can be asserted that the decrease in material grain size is, in fact, only the consequence of many different processes accompanying plastic deformation in metals. We have performed a constitutive experimental, FEM and discrete complex based studies for two copper alloys subjected to ECAP and MDF deformation processes. This combination of methods allows for recognising complementary microstructural effects, such as micro- and macro localization phenomena, coupled dislocation cells and grains evolution, inhomogeneities of triple junction network and ultrafine grain emergence. In many cases, the obtained deformational inhomogeneities play a substantial role both for deformation at macro- and microscale levels. Heterogeneity of grain boundary junction network could be critical for design of nanostructured copper-based alloys suitable for electrical applications.
10.1016-j.matchar.2019.109886	-1		Bulk naoocrystalline (NC) materials possess high volume fraction (up to 50%) of grain boundaries (GBs), which contributes significantly to their mechanical and physical properties. Nevertheless, high density of dislocations at GBs and the associated strain fields complicate the analyses on the fine GBs structures of NC materials. Here, taking NC Cu-based alloys as model systems, the atomic-scale configurations of dislocations and typical GBs triggered by severe plastic deformation are well investigated using aberration-corrected high-resolution transmission electron microscopy and geometric phase analysis. A periodic array of extended dislocations with a spacing of 2.2 nm is found to form low-angle GBs (LAGBs) in NC Cu-based alloys. The interaction between dislocations and twins play a crucial role in forming the GBs of NC. Twin boundaries (TBs) in NC Cu-based alloys can serve as barriers for trapping dislocations, which in turn tune the TBs directly evolving into LAGBs or high-angle GBs. In addition, a symmetric 6 [001] tilt LAGB is also analyzed to be composed of a/2 < 100 > edge dislocations, which are activated by the a/2 < 110 > full dislocation dissociation or simple shear deformation of {100} planes. Our study offers insights into the atomic resolution structures of dislocations and GBs in NC materials.
10.1016-j.matchar.2019.109940	-1		In this work, the fatigue properties and cyclic deformation behavior of cold-drawn and annealed Cu-Cr-Zr alloys were investigated via low-cycle fatigue (LCF) testing at room temperature. The microstructure and fatigue fracture of the alloy were analyzed by scanning electron microscopy, electron backscattered diffraction, and transmission electron microscopy. The results show that because of recrystallization grain growth during the annealing process, the LCF life of the annealed Cu-Cr-Zr alloy were lower than those of the cold-drawn Cu-Cr-Zr alloy when the total strain amplitude was less than or equal to 0.7%. The cold-drawn Cu-Cr-Zr alloy exhibits the Bauschinger effect at low total strain amplitudes (0.4% and 0.45%). In addition, the initiation and propagation of fatigue cracks of the two alloys occurred in a transgranular manner. The evolution of the cyclic microstructure of the two selected materials after different total strain amplitudes was significantly different, the dislocation density of cold-drawn Cu-Cr-Zr alloy decreases with the increase of the total strain amplitude, while that of the annealed Cu-Cr-Zr alloy increases.
10.1016-j.matchar.2019.110091	-1		A Cu-3Ag-1Zr alloy was fabricated by rapid solidification and cold rolling. The microstructure stability and tensile properties of this alloy after isochronal annealing at 350-900 degrees C were investigated. The results show that the microstructure of the Cu-3Ag-1Zr alloy after annealing at 350 degrees C for 1 h is dominated by the high-density dislocations, ultrafine grains, low angle grain boundaries (LABs) and second-phase particles (nano-sized Ag and micro-sized Cu4AgZr), which results in a high tensile strength of 637 MPa and moderate elongation of 12%. When annealed at 400 degrees C, the particle stimulated nucleation of recrystallization (PSN) occurs, and the fraction of LABs decreases to 38%, but over 90% of grains are smaller than 2 mu m. The decreased tensile strength (465 MPa) and increased elongation (30%) are closely related to the fully recrystallized microstructure after annealing at 500 degrees C. The alloy exhibits excellent thermal stability when annealed between 500 and 800 degrees C, and no significant coarsening of grains and decrease in strength are observed due to the strong pinning effect of the stable Cu4AgZr particles at boundaries. The coarsening of the Cu4AgZr particles at 900 degrees C leads to the sharp increase in the grain size and drop of strength .
10.1016-j.matchar.2019.110112	6	grain; deformation; strain; strength; dislocation; cu-; tensile; size; ecap; grain size; sfe; ductility; hardening; high; stress	Hot uniaxial compression tests were carried out on Cu-0.8Cr-0.05Zr-0.05Ti (wt%) alloy specimens with three different grain sizes: 30 pm, 150 pm and 450 pm to study the effect of initial grain size on hot workability of the alloy. The deformation temperature and applied strain rate ranges were 600-900 degrees C and 0.001-1 s(-1) respectively. At higher deformation temperatures, fine grained specimens exhibited early onset of dynamic recrystallization (DRX) as compared to coarse-grained specimens. Conversely, the work hardening plots of coarse-grained specimens exhibited plateaux at higher strain rates indicating occurrence of deformation twinning. Microstructure examination revealed a decrease in the extent of DRX and an increase in deformation twinning with increase in initial grain size. The failure in coarse-grained specimens was in the form of wedge cracking observed at triple junctions at lower deformation temperatures. The higher stress values exhibited by coarse-grained specimens as compared to fine grained specimens was found to be a result of absence of DRX and the strain being accommodated by deformation twinning rather than grain boundary sliding (GBS) due to limited grain boundary area. Processing maps using the dynamic material model (DMM) were plotted for all three initial grain sizes and were validated with optical microstructures. The 'unstable/unsafe' deformation domain was found to be wider with increase in initial grain size. The present study explicates that there is an increase in difficulty of hot working and reduced control of microstructure in the alloy with increase in initial grain size.
10.1016-j.matchar.2020.110194	-1		This study investigated the effect of heat treatment on the microstructure, room- and high-temperature mechanical properties, and thermal properties of selective laser melted Cu-Ni-Sn alloy. Initial microstructural observation confirmed that the as-fabricated sample was composed of Cu, Cu6Sn5, Cu3P and undissolved Ni phases, and then the heat-treated sample was composed of Cu-Ni solid solution, (Cu, Ni)(3)Sn and (Cu, Ni)(3)P. Room- and high-temperature compression tests (25 degrees C similar to 500 degrees C) were performed, and the yield strengths at room temperature measured 230.4 MPa and 346.0 MPa for as-fabricated and heat-treated materials, which indicates an approximately 50% increase in strength after heat treatment. Furthermore, as temperature increased, a phenomenon where the yield strength inverts occurred for both materials, and the cause of such a phenomenon was identified to be due to the difference in strengthening mechanisms. Thermal diffusivity is lower in heat-treated sample at all temperatures, but on the other hand, thermal conductivity interestingly is higher in heat-treated sample than as-fabricated sample (As-fabricated sample: 30.7-44.0 W/m.K, heat-treated sample: 32.8-49.6 W/m.K). The reason for this is identified to be due to microstructure evolution and defect control after heat treatment. Correlations between initial microstructures and mechanical- and thermophysical-properties were also discussed based on these findings.
10.1016-j.matchar.2020.110476	-1		High-strength and high-elastic copper alloy not only has super mechanical properties, but also has good corrosion resistance. Therefore, it is widely used in marine engineering. In this paper, three kinds of CuNiMnNbCrZr alloy with different Al contents are designed. And their mechanical properties and corrosion behavior in 3.5 wt% NaCl solution were studied. The Cu-20Ni-20Mn-0.3Nb-0.3Cr-0.3Zr alloy has good mechanical properties (Tensile strength: 1445 MPa, Yield strength: 1223 MPa, Elongation: 6.8%) and nice corrosion resistance (Corrosion rate: 0.0087 mm/a). By comparing the polarization resistance, self-corrosion potential, equivalent resistance and XPS analysis of three alloys, a further enhanced corrosion resistance is found in the alloy with Al element added. The results revealed that a dense Al2O3 film was formed during the corrosion process, which prevented the substrate from being corroded. These newly developed high-strength and high-elasticity copper alloys have great potential for marine environment applications.
10.1016-j.matchar.2020.110546	6	grain; deformation; strain; strength; dislocation; cu-; tensile; size; ecap; grain size; sfe; ductility; hardening; high; stress	Mechanical properties of Cu-5 at%Al alloy with different recrystallization fractions ranging from 0% to 100% are studied by tensile tests at 77 K and 293 K, respectively. The relationship between uniform elongation and recrystallization fraction had been unveiled. The uniform elongation and recrystallization fraction have a transition from single-stage to two-stage relationship with decreasing deformation temperature from 293 K to 77 K, which is related to the strain gradient and deformation twinning in recrystallized grains. In addition, the conventional trade-off relationship between strength and ductility has been broken via tailoring the heterogeneous microstructures at 77 K.
10.1016-j.matchar.2020.110642	-1		The discontinuous precipitation (DP) was known to mechanically detrimental mechanism compared to normal precipitation (continuous precipitation, CP), while the DP has the higher conductivity because of low solute content in matrix. To get the optimum balance of strength and conductivity, the bimodal-structured Cu-4Ni-1Si alloy composed of two regions with CPs and DPs was fabricated. Bimodal-structured alloy occupied by 50% of each region shows remarkable high strength and conductivity combination (1088 MPa / 38%IACS) beyond the expected values which summated in alloys with fully CP or DP. The accelerated strengthening of bimodalstructured alloy is caused by uni-directional alignment and enhanced plastic deformation of DPs in alloy after cold-working.
10.1016-j.matchar.2020.110656	8	hot; deformation; strain; strain rate; dynamic; hot deformation; recrystallization; dynamic recrystallization; flow; rate; flow stress; compression; constitutive; degrees; stress	Cu-Ni-Si alloy is widely used in electronics industry due to its high electrical conductivity and high strength . In this paper, the Cu-Ni-Co-Si-Cr alloy is prepared by ZG-0.01 vacuum frequency induction melting furnace. The hot compression tests of the Cu-1.5Ni-1.1Co-0.65Si-0.2Cr alloy were carried out using the Gleeble-1500 simu-lator at 0.001-10 s(-1) strain rates and 500-900 degrees C deformation temperatures. The microstructure changes of the alloy at 500-900 degrees C were studied. The changes in the hot deformation process for the Cu-1.5Ni-1.1Co-0.65Si0.2Cr alloy were analyzed by EBSD. The dislocation density was sacrificed to promote recrystallization. The DRX grains texture of the alloy at 700 degrees C is {001} < 100 > {011} < 100 > Goss texture at 900 degrees C. And the higher deformation temperature makes the texture more random by lowering the texture intensity. The precipitates of the Cu-1.5Ni-1.1Co-0.65Si-0.2Cr alloy are mainly disk shaped and rod-shaped (Ni, Co)(2)Si. The constitutive equation of the Cu-1.5Ni-1.1Co-0.65Si-0.2Cr alloy was established to predict the behavior of the flow stress, and the activation energy is 634.45KJ/mol. Due to precipitation-hardened caused by (Ni, Co)(2)Si, the activation energy of the Cu-1.5Ni-1.1Co-0.65Si-0.2Cr alloy was much higher than the self-diffusion activation energy of pure copper. And the CDRX and DDRX mechanisms are two dominant DRX mechanisms for the Cu-1.5Ni-1.1Co-0.65Si-0.2Cr alloy.
10.1016-j.matchar.2020.110760	-1		The microstructure and subsequent phase transformations of Cu-15Ni-8Sn can get affected by a minor addition of phosphorus (P). For the first time, the hexagonal Ni10SnP3 phase was observed in the Cu-15M-8Sn-0.2P alloy using high-angle annular dark-field scanning transmission electron microscopy (HAADF-STEM) and transmission electron microscope (TEM). Further, the atomic size factor increased which was responsible for the promotion of the spinodal decomposition and ordering in Cu-15Ni-8Sn alloy with P addition. Moreover, the Ni10SnP3 phase precipitated along the grain boundary, and the precipitation free-zone was observed near the grain boundary. Nonetheless, these were the primary causes observed for the inhibition of discontinuous precipitation (DP) with P addition.
10.1016-j.matchar.2020.110847	-1		In this work, a highly wear-resistant cooper matrix composite reinforced by in situ formed nano-NbC particles was synthesized by hot pressing mechanically alloyed Cu+Nb+C powders. The composite possesses a smaller friction coefficient and displays a wear rate (2.6 x 10(-5) mm3N(-1) m(-1)) two orders of magnitude lower than the micro-NbC reinforced Cu composites (123.5 x 10(-5) mm(3)N(-1) m(-1)). Such property enhancement is attributed to the hardness improvement and the solid lubricating effects induced by nanoscale niobium carbides/oxides as well as iron oxides. The oxidation and pulverization of NbC during friction have played a key role in increasing the wear resistance and their mechanisms are discussed. The findings provided a strategy for developing other wear-resistant composite materials.
10.1016-j.matchar.2021.110878	-1		The reuse potential of SnPb-solder affected old/waste copper is investigated under the influence of work hardening and thermal treatments. In fact, the urge of using old copper to manufacture new components necessitates useful characterization of various properties to explore its reuse potential. In this context, a number of physico-mechanical properties of interest, namely, hardness, conductivity, thermal stability, structure, etc. are chosen here to characterize the solder-affected copper materials as well as analyze their possible changes/improvements under the influence of work-hardening and thermal treatments. Since the old/waste copper usually contains little amount of lead and tin, three additional sample materials, such as, copper ingots, copper-tin alloy, and copper-lead alloy are taken into consideration to ascertain the influence of individual solder elements on the properties of the copper alloy. It is observed that addition of trace amount of tin and lead can significantly influence micro-hardness, conductivity, thermal capacity, etc. Micro-hardness values of all four sample materials have been found to be increasing in curvilinear pattern with the rise of cold-rolling level up to 50- 55% and then get flatten, and cold-rolled work-hardening level of similar to 35% is found to be a critical deformation level where the hardness of Cu-Pb alloy supersedes pure Cu and Cu-Sn-Pb alloy supersedes Cu-Sn alloy. Electrical conductivity of Cu falls drastically with the addition of only about 1% Sn or 1% Pb, which increases little initially after cold-rolled deformation up to similar to 35% and start falling again with the rise of deformation levels. Shifting of endothermic peak has occurred and thereby recrystallization temperature of Cu is transformed as an effect of alloying due to inclusion of SnPb-solder in Cu as well as work hardening. Micrographs have confirmed the structural changes responsible for the variation of electro-mechanical properties.
10.1016-j.matchar.2021.111099	15	aging; strength; conductivity; electrical conductivity; electrical; mpa; treatment; strengthening; degrees; cu-; cold; precipitation; tensile strength; tensile; iacs	A novel Cu-Co-Ti alloy with high strength of 480 MPa, high conductivity of 81% IACS and excellent softening temperature up to 600 degrees C was fabricated via solid solution, cold rolling, and aging treatment. Various means were used to study the strengthening, conductive and anti-softening mechanisms of the alloys. It was detected that Co and Ti reacted and precipitated during the aging process. Both theoretical calculations and experimental results revealed that the solid solution scattering and precipitation strengthening were the dominant mechanisms that affected the electrical and mechanical properties of the alloy, respectively. While the high softening temperature of the alloy was mainly due to the coarsening of the precipitates was restricted by the diffusion rate of Co in the Cu matrix.
10.1016-j.matchar.2021.111104	-1		The strengthening effects of Cr on Cu-Cr alloys are severely limited due to the relatively low solid solubility of Cr in Cu phase. Apart from the dissolved Cr, it should be noted that a high proportion of Cr in Cu matrix work as the second phase dispersion strengthening. To effectively improve the strengthening effect of Cr in Cu-Cr alloys, it is important to enhance the dispersion strengthening effect of the second phase Cr. In this work, the Cr phase could be strengthened by dissolving Cu atoms through the levitation melting method (LM), without additional alloying element was introduced. The results show that a maximum of Cu (0.46-0.54 wt%) is dissolved into Cr phase in Cu2Cr98 and Cu5Cr95 alloys. The corresponding hardness is 38% and 56% higher for Cu2Cr98 and Cu5Cr95 alloys compared with pure Cr, respectively. This novel strengthening mechanism of the enhanced Cr second phase is further applied in CuCr25 alloys. It is confirmed that the hardness is 57% higher for CuCr25 with enhanced Cr phase than that prepared using conventional methods. Furthermore, the significant strengthening effect is confirmed in the tribological properties. This strategy can be utilized to effectively enhance the mechanical performance of Cu-Cr alloys with high Cr content.
10.1016-j.matchar.2021.111191	-1		The nanostructured Cu coatings were electrodeposited with different vibration, such as vibration-free, agitation and ultrasonic.Ultrasonic could help to refine grains and optimize the comprehensive performance of the coating. The effect of vibration on the thermal stability of pure Cu coatings was investigated with the coatings annealing at 450 degrees C, 500 degrees C and 550 degrees C. Both agitation and ultrasonic can suppress the nanograins coarsening and the effect of ultrasonic was more excellent. Ultrasonic can not only increase the content of nanotwins and triple junctions but also induce the relaxation of GBs. Therefore, the ultrasonic deposited nanograins in the low-energy state exhibit superior thermal stability. The mechanisms of the thermal stability in the electrodeposited coatings were studied from thermodynamics and dynamics. By comparing dislocation density, stacking faults energy and grain boundaries energy, it was proved that the driving force of grain growth in the ultrasonic deposited coating was lowest. Both the methods of isothermal measurements and Kissinger showed that the ultrasonic could increase the activation energy of grain growth to inhibit grain boundary mobility.
10.1016-j.matchar.2021.111205	-1		Copper matrix nanocomposites reinforced by Al2O3 nanoparticles were fabricated by accumulative roll-bonding (ARB) processed to ultrahigh rolling cycles. The effects of ARB cycles on the distribution of Al2O3 nanoparticles and properties of the nanocomposites were investigated. It was found that a higher ARB cycle was needed to obtain a uniform distribution of Al2O3 nanoparticles with a larger volume fraction. Significant strengthening, as well as a good combination of tensile strength and electrical conductivity of the Cu-Al2O3 nanocomposites can be obtained, through optimizing the uniform dispersion of Al2O3 nanoparticles by applying ultrahigh ARB cycles. The enhanced strength (maximum: 735 MPa) of the nanocomposites can be attributed to the maximized contribution of nanoparticles by various mechanisms through optimizing the uniform dispersion of them.
10.1016-j.matchar.2021.111502	-1		The effects of Y for the microstructure evolutions of Cu-Co-Si alloys during hot deformation were investigated. The hot deformation behaviors for Cu-2.6Co-0.655i and Cu-2.6Co-0.655i-0.2Y alloys were carried out on the Gleeble-1500 simulator with the strain rates from 0.001 to 10 s(-1) and temperatures from 500 degrees C to 900 degrees C. The hot deformation activation energies for two copper alloys were calculated and the constitutive equations were also established. According to the true stress-strain curves and EBSD image analysis, it showed that the nucleation of dynamic recrystallization (DRX) grain and the growth of DRX grain were promoted with the addition of 0.2 wt% Y. Electron backscatter diffraction (EBSD) was used to characterize the microstructure of the hot deformed Cu-Co-Si alloy. The electrode diagram and ODF diagram were established to analyze the textures. The texture strength and the number of small angle grain boundaries were reduced by the addition of 0.2 wt% Y. The microstructure of two alloys was analyzed by transmission electron microscopy, it was found that a large number of Co2Si nanoparticles were distributed on the copper matrix. Y could promote the precipitation process of delta-Co2Si, and these nanoparticles interacted with dislocations during the hot deformation process to improve the deformation resistance.
10.1016-j.matchar.2021.111565	15	aging; strength; conductivity; electrical conductivity; electrical; mpa; treatment; strengthening; degrees; cu-; cold; precipitation; tensile strength; tensile; iacs	There is a challenging trade-off between the high strength and high electrical conductivity in copper-based alloys. Designed Cu-3.65 wt%Nb (CN) and Cu-3.48 wt%Nb-0.11 wt%Si (CNS) alloys were fabricated by vacuum melting and followed by thermal-mechanical treatment. Microstructure evolutions and properties measurements were studied. Results indicate that morphologies of the Nb3Si phase in the CNS alloy are solid or hollow regular polygons whose boundaries are parallel to one of Nb3Si's crystal faces. The Nb3Si's precipitation can effectively improve the strength, while the Nb3Si tip is easy to form stress concentration, which leads to crack and failure. The high electrical conductivity of the CNS alloy was because of the decomposition precipitation of Nb and Nb3Si during aging treatment. After hot-rolled by 80% at 900 degrees C, cold-rolled with a strain of 2.30, the ultimate tensile strength of CN and CNS alloys were 488 MPa and 510 MPa, electrical conductivities were 88.06%IACS (International Annealed Copper Standard) and 93.20%IACS, and elongation rates were 9.3% and 7.1%, respectively. These findings reported a new method to fabricate high-strength and high-conductivity copper alloy.
10.1016-j.matchar.2021.111590	-1		This study presents the outcomes of an investigation of the effect of wt% of cerium and Aluminium on the phases, crystal structure, microstructure, morphology, phase transformation temperatures, shape recovery ratio and mechanical properties of the polycrystalline Cu-Al-Be shape memory alloys (SMAs). SMAs exhibit martensite phase at room temperature up to 0.49 wt% of Be and >= 0.52 wt% of Be transforms to austenite phase. An increase in cerium by 0, 0.05, 0.1, 0.15 and 0.2 wt% decreases the grain size by 0, 70.87%, 82.73%, 83.8% and 94.6%, respectively. An increase in cerium increases the transformation temperatures owing to the Al-rich secondary precipitates, and the shape recovery ratio reduces. Alloying cerium of 0.1 wt% exhibits a maximum tensile strength of 474 +/- 23 MPa with the ductility of 24.11 +/- 1.42%.
10.1016-j.matchar.2021.111605	-1		A Cu alloy with discontinuous precipitation (DP) presents a mechanically lower strength, but a higher conductivity compared to an alloy with continuous precipitation (CP). We controlled the partial distribution of DP in the Cu matrix of Cu-4Ni-1Si alloy by changing aging time. Successive cold-working of the alloy showed that by controlling the CP and DP fractions, considerably wide ranges of strength and electrical conductivity, from 500 to 1170 MPa, and from 23 to 50% IACS, respectively, could be achieved. After cold-working, the DP region in the alloy was heavily deformed in comparison with the CP region, showing a drastic increase in strength, with only a small decrease in conductivity.
10.1016-j.matchar.2021.111670	10	composites; nanoparticles; strength; matrix; high; strengthening; particles; conductivity; composite; electrical; mpa; sintering; ods; grains; mechanical	The substitution of a precipitation-hardenable alloy of Cu-0.5wt%Cr for the widely adopted pure Cu has been proposed for infiltration into the pre-sintered concrete skeleton of particulate and fibrous W. By the reinforcement of a concrete skeleton of particulate and fibrous W along with coherent Cr precipitates in the Cu matrix, the composite exhibited superior comprehensive properties. Specifically, the proposed composite here exhibited a high tensile strength of 601.2 MPa improved by 22.7%, a low friction coefficient of 0.567 decreased by 27.3% and high electrical breakdown strength of 9.07 x 10(7) V/m increased by 101.5%. Notably, due to the precipitation of the coherent Cr particles to lower the solute content in the Cu matrix, the composite exhibited rather good electrical conductivity of 51.4%IACS. The proposed strategy by infiltration of precipitation-hardenable Cu-based alloys into the W skeleton here provides a new clue for the microstructure design and performance enhancement of novel W-Cu composites.
10.1016-j.matchar.2021.111707	-1		The effect of hot rolling on the evolution of Fe phase and the properties of Cu-6.5Fe-0.3 Mg alloy is explored. The results show that the optimal performance (i.e. ultimate tensile strength (818 MPa), electrical conductivity (61.7%IACS), and electromagnetic shielding (85-100 dB)) was obtained by hot rolling + cold rolling + heat treatment. It was found that the tadpole-like Fe phase in the Cu-6.5Fe-0.3 Mg alloy after primary hot rolling was smaller and denser than those after primary cold rolling, which is attributed to the hot grooving and splitting behavior of the Fe phase during hot rolling. The depth of thermal slotting of the Fe phase increases with the increasing of the heat treatment temperature. After large plastic deformation, the tadpole-like Fe phases transforms into Fe fibers and its density is higher. The strengthening method of Cu-6.5Fe-0.3 Mg alloy is fiber reinforcement and its electromagnetic shielding performance increases with the density of Fe fibers. The splitting of the Fe phase during hot rolling significantly increases the density of Fe fiber, thereby improving its tensile strength and electromagnetic shielding performance. This work will provide a new guideline for the preparation of high-performance Cu-Fe-Mg alloys.
10.1016-j.matchar.2022.111808	-1		A Y-Ti-O oxide-dispersion-strengthened (ODS) Cu alloy has been successfully fabricated by mechanical alloying (MA) and spark plasma sintering (SPS). Excessive cold-welding during high energy ball-milling was effectively suppressed by mixing TiO2 and pre-alloyed Cu(Y) powders as the raw powders. Microstructural evolutions during the MA and SPS processes and the subsequent annealing were investigated with a focus on the Y-Ti-O nanooxides. The 12 h ball-milling failed to achieve super-saturations of Y, Ti, and O in Cu, which led to the in-situ formation of various types of oversized Y/Ti-rich oxides with very irregular morphologies during the SPS. With a prolonged ball-milling of 48 h, the subsequent SPS + annealing processes can promote a high density precipitation of ultra-fine Y-Ti-O nano-oxides. These nano-oxides were further identified as Y2Ti2O7 mostly, with a high degree of coherency in Cu. Fabricating Y-Ti-O ODS-Cu alloys via MA was thus confirmed to be technically feasible, although the dispersion of nano-oxides desires further improvement.
10.1016-j.matchar.2022.111813	6	grain; deformation; strain; strength; dislocation; cu-; tensile; size; ecap; grain size; sfe; ductility; hardening; high; stress	Uniaxial (UC) and plane strain compression (PSC) tests were performed on the Cu-Cr-Zr-Ti alloy specimens to investigate the effect of the deformation mode on the stress-strain response, work hardening behaviour and microstructural evolution in the alloy. These tests were performed at a strain rate of 1 s-1 and in the temperature range of 700-800 degrees C to impart von Mises equivalent strains of 0.15, 0.45 and 0.69. The alloy showed a regime of constant work hardening rate in the recovery stage before transitioning to the steady state under UC as opposed to PSC in which the alloy exhibited a smooth transition from recovery stage to the steady state stage. The microstructures evolved under UC consisted of randomly oriented equiaxed grains delineated by high angle boundaries (HABs) with high fraction of sigma 3 boundaries. On the other hand, under PSC a very strong {001}100 cube texture evolved with increase in strain. This strong cube texture was ascribed to the evolution of and the increased stability of cube-oriented elongated substructures observed in the deformed matrix. The difference in the work hardening behaviour was thus attributed to the higher evolved sigma 3 fraction under UC and the cubeoriented elongated substructures evolved under PSC. The dynamically recrystallized grains fraction calculated from area of grain orientation spread (GOS) map with GOS < 2o was found to be lower in the alloy under PSC owing to the presence of high orientation gradients within the evolved cube-oriented elongated substructures.
10.1016-j.matchar.2022.111878	-1		Achieving an excellent combination of mechanical properties and electrical conductivity in conductive copper alloys is highly desirable but remains a great challenge. This paper reports a dual heterogeneous laminated (DHLed) Cu/Cu-Cr-Zr composite structure in copper alloys produced by accumulative roll bonding (ARB) and annealing process that can produce an excellent property combination: high strength (ultimate tensile strength: 563.4 +/- 14 MPa), sufficient tensile ductility (uniform elongation: similar to 16.2%), and high conductivity (similar to 92%IACS). The specially designed DHLed Cu/Cu-Cr-Zr composite microstructure is characterized by alternating coarse- and ultra-fine grain layers and layered distribution of precipitations. Such dramatic microstructure heterogeneities produce significant hetero-deformation induced hardening due to mechanical incompatibility between soft Cu and hard Cu-Cr-Zr layers, which leads to an excellent combination of strength and ductility. The high conductivity can be attributed to the unique DHLed Cu/Cu-Cr-Zr composite structure containing alternating recrystallized- and nanolaminated-grain layers.
10.1016-j.matchar.2022.111911	-1		One of the most important goals in the development of Cu-based alloys for electrical engineering applications is the realization of materials with both high mechanical strength and electrical conductivity. Cu-Ti alloys are promising alternatives to Cu-Be alloys, which are expensive and can be hazardous to health . Herein, an agehardenable binary Cu96Ti4 alloy and its Mg-doped analog were compared by advanced electron microscopy techniques. The mechanical properties of the Mg-doped alloy are superior to those of the binary alloy. The effects of Mg-doping on the microstructure are investigated by atomic-scale scanning transmission electron microscopy combined with energy-dispersive X-ray spectroscopy. The Cu96Ti4 (at%) solid-solution alloy developed lamellar aggregates when subjected to prolonged aging treatment at 450 degrees C for 100 h owing to discontinuous precipitation (DP) along the grain boundaries. The DP consisted of a face-centered cubic (FCC) Cu solid-solution phase (denoted as a-Cuss) and a stable Cu4Ti intermetallic phase (beta-Cu4Ti). Conversely, while the Cu94Ti4Mg2 counterpart had similar lamellar aggregates, the amount of these aggregates was reduced, and no beta-Cu4Ti phase was observed. The lamellar in the Cu94Ti4Mg2 counterpart consisted of two distinct FCC Cuss phases with different Tisolute contents. Accordingly, the possible effects of Mg doping on the local structures of the DP in the Cu-Ti alloy are explained, and the structural characteristics of the DP that may result in improved mechanical properties is discussed.
10.1016-j.matchar.2022.111965	-1		We studied nucleation and growth of Ag precipitates in a Cu-6 wt%Ag-0.15 wt%Sc alloy and found that the early nucleation of Ag precipitates was similar to continuous precipitation in that it occurred only on dislocations within Cu grains, not on any grain boundaries. In aged samples, we observed stacking faults that extended into nanotwins. These planar defects formed during early nucleation of Ag precipitates and extended into the sur-rounding Cu matrix. The formation of planar defects released misfit strain on Cu/Ag interfaces, enhancing subsequent nucleation and growth of Ag precipitates. Unlike the intrinsic defects found in previous research, these defects were clearly extrinsic. The planar defects provided a row of additional sites aligned along twin boundaries for the nucleation of Ag precipitates. The formation of new Ag precipitates, by reducing dissolved Ag in the Cu matrix, increased conductivity significantly. Planar defects reduced electrical conductivity somewhat, but the synergy between Ag precipitation combined with planar defects had the effect of substantially increasing both hardness and conductivity.
10.1016-j.matchar.2022.112045	6	grain; deformation; strain; strength; dislocation; cu-; tensile; size; ecap; grain size; sfe; ductility; hardening; high; stress	Severe Plastic Deformation (SPD) routes, such as Equal Channel Angular Pressing (ECAP), are capable of producing ultrafine-grained (UFG) materials with outstanding mechanical properties. Although grain refinement and the increase in mechanical processing could be enhanced through ECAP processing at cryogenic temperatures, this route presents the drawback of microstructural instability, which is responsible for reversing the gain in mechanical properties and microstructure refinement when the material is stored at room temperature or submitted to relatively high temperatures. Aiming to design severely deformed and stable microstructures, this study investigated pure copper (Cu) and a commercial ITER-grade Cu-0.7Cr-0.07Zr alloy submitted to ECAP at 298 and 123 K followed by annealing heat treatments. ECAP processing introduced a high density of dislocations and vacancy concentration in the materials assessed. Pure Cu showed poor microstructural stability when longterm stored at room temperature after ECAP processing at cryogenic temperatures, and when submitted to annealing post-ECAP processing. In contrast, the Cu-0.7Cr-0.07Zr alloy submitted to cryo-ECAP showed outstanding thermal stability even when submitted to annealing at 673 K for 120 min. For this alloy, the fine Crrich precipitates were responsible for preventing static recovery and preserving a grain size of -6.6 mu m and an area fraction of recrystallized grains of 6.2%. Finally, it was possible to pave the way for the design of refined and stable microstructures after cryo-SPD processing.
10.1016-j.matchar.2022.112096	-1		The spherical TiB2/Cu composite powder was fabricated by a new method of liquid-phase in-situ reaction coupled with inert gas atomization. The powder morphology, characteristic indexes, microstructure and nano-indentation hardness were investigated. The effects of spheroidization time and solidification rate of atomized molten droplets on powder sphericity and the relationship between in-situ reaction control and TiB2 distribution were discussed. Results indicate that the powder has a good sphericity and d(50) is 32.86 mu m, in addition to 75% fine powder yield (<45 mu m). The in-situ formed TiB2 particles (TiB2p) were uniformly distributed in grain boundaries and intragrain. The rapid solidification of molten droplets and the inhibition of copper grain growth by TiB2p refined the Cu matrix grain size (4.34 mu m). The nanoindentation hardness of composite powder is 3.17 GPa, which is 1.9 times higher than that of spherical Cu powder, and the reasons for the increased hardness of powder are also discussed.
10.1016-j.matchar.2022.112352	-1		Bismuth (Bi), as an impurity element in copper and copper-based alloys, usually leads to the catastrophic intergranular fracture even with a ppm concentration. However, the intrinsic mechanisms of the embrittlement remain largely unclear and the control of such a brittleness has been rarely reported. Here, we investigate the influence of trace amounts of Bi on the ductility of ultrahigh-purity copper (99.99999%) at temperatures be-tween room temperature (RT) and 900 degrees C. On this basis, the ductility improvement of Cu-Bi alloy by adding different concentration of Ce is also systematically studied. Compared to the ultrahigh-purity copper, the Bi-containing alloy exhibits a remarkable decrease in ductility, with the severe reduction occurs at 450-900 degrees C. This is caused by the grain boundary (GB) segregation of Bi layers, which reduces the GB cohesion because of the weak Bi-Bi bonds. However, after trace Ce are added, the ductility of Cu-Bi alloy in the temperature range of 450-900 degrees C is significantly increased. The obvious enhancement is due to the reaction behavior of Ce and Bi to form the precipitated phases, as well as the preferential segregation of Ce to GBs and phase boundaries, which change the existing form of Bi in copper. Our findings provide a comprehensive understanding on the micro -structural origin of Bi-induced GB embrittlement and an effective way for inhibiting such an embrittlement.
10.1016-j.matchar.2022.112451	15	aging; strength; conductivity; electrical conductivity; electrical; mpa; treatment; strengthening; degrees; cu-; cold; precipitation; tensile strength; tensile; iacs	In this paper, the effects of Nb addition on the mechanical properties, electrical conductivity and microstructure of the Cu-Ni-Si-Mg alloy were investigated. The results show that, after the secondary aging at 460 degrees C for 120 min, the alloy with 0.2 wt% Nb exhibits the best comprehensive properties with a hardness of 245.9 HV, a tensile strength of 747.28 MPa, a breaking elongation of 8.6%, and an electrical conductivity of 47.74 %IACS. The addition of Nb element can promote the precipitation of Ni2Si phase. The Nb-doped alloy has a higher quantity of precipitates and a smaller size of precipitates. The Nb element promotes the transition of the Ni2Si phase from a coherent to an incoherent relationship with the matrix in the Cu-Ni-Si-Mg alloy. In the initial stage of precipi-tation, the precipitation activation energy of the alloy with 0.2 wt% Nb is 46.86% lower than that of the alloy without Nb. The addition of Nb increases the proportion of sigma 3n (n = 1, 2, 3) grain boundary in the Cu-Ni-Si-Mg alloy. Furthermore, after the secondary aging, the Nb addition increases the recrystallized texture and recrys-tallized grains and decreases the cold-rolled texture and defects in the alloy.
10.1016-j.matchar.2022.112494	-1		Copper alloys are widely used as lead frames, electric contact wires and pantographs due to their high electrical conductivity and excellent mechanical properties. At present work, a medium electrical conductivity and excellent mechanical properties of Cu-Co-Si-Ti-Ce alloy was obtained by the vacuum melting process with the optimum performance of 225 HV, 702.5 MPa and 40.8% IACS aging at 500 degrees C for 60 min via the combinations of multiple strengthening. It can be inferred that the high-volume fraction of Goss, Brass, copper and S texture was one of the main reasons for the increase of micro-hardness by comparing the texture content at different con-ditions. Moreover, it was observed that Co2Si and Co16Ti6Si7 phases exhibited coherent and semi-coherent interface relationships with the copper matrix, respectively, which can relieve the interfacial stress and reduce the interface energy by GPA analysis. Finally, the contributions of solid solution strengthening, work-hardening, grain boundary strengthening and precipitation strengthening were calculated, contributing most to the pre-cipitation strengthening.
10.1016-j.matchar.2022.112568	-1		Bi-layered Cu-Pb-Sn bronze/steel sheets serving as raw material for load-bearing shells require urgent upgrading of mechanical properties for service safety. This study investigated the mechanical properties and deformation behaviors of a bi-layered Cu-Pb-Sn bronze/steel sheet prepared by solid-liquid continuous casting (SLC). The samples were identified by two types of bronze microstructures: homogeneous and segregated Pb phase distri-butions, denoted as HP and SP, respectively. The Pb phase in HP is mainly in the form of uniformly distributed small particles, while in SP, the segregation and high content of large continuous phases are formed at grain boundaries. These samples were tested for their tensile properties and residual stress. We found that the yield strength and fracture elongation of SP are higher than those of HP, contrary to the general understanding that Pb phase segregation will degrade the mechanical properties of Cu-Pb-Sn alloys. Characterization of the fractures and residual stress results suggest that the increase in SP yield strength is attributed to the higher required shear stress for yielding induced by the residual stress state. The higher fracture elongation originates from the for-mation of multiple cracks that accommodate the bi-layered structure's deformation incompatibility.
10.1016-j.matchar.2022.112600	-1		Cu-Fe composites are a new generation of electromagnetic shielding materials. However, the substructure evolution of the two-phase composite is not clear in the aging process, and its plastic deformability is very limited in the nanostructured regime. In this work, nanostructured Cu-10Fe composites were prepared by heavy cold rolling, and the microstructure evolution and properties of the composites during aging were systematically studied. With increasing aging temperature, the strength and ductility change monotonically, while the electrical conductivity first increases and then decreases. Mechanisms for superior mechanical and electrical properties are further discussed, by quantifying the contributions of different microstructural constitutes.
10.1016-j.matchar.2022.112613	-1		In the present study, a novel multicomponent accumulative roll bonding (MARB) approach was proposed and successfully applied to prepare a nanostructured Ag/Cu multilayered composite. Microstructure, hardness and conductivity of Ag/Cu multilayered composites with different MARB cycles were investigated by electron backscatter diffraction, transmission electron microscopy, nanoindentation and four-point probe direct current methods. It is demonstrated that the MARB approach is able to effectively suppress the shear band formation and result in a remarkable reduction in the thickness of the Ag/Cu multilayered composite down to 40 nm via only 6 cycles. The as-prepared nanostructured Ag/Cu multilayered composite exhibits an excellent combination of high hardness (2.24 GPa) and high electrical conductivity (equivalent to 84% of international annealed copper standard; IACS). It owes these extraordinary properties to the atomically ordered and chemically sharp heter-ophase interfaces and low density of grain boundaries resulting from the MARB process.
10.1016-j.matchar.2023.112675	-1		A micro-alloyed copper powder, Cu-0.3Zr-0.15Ag wt%, was produced using gas atomization reaction synthesis. Zirconium was added to copper to sequester the oxygen present as copper oxide surface films on the powder particles. The as-received powders, as well as the intentionally oxidized powders were used to fabricate solid test articles by electron beam powder bed fusion additive manufacturing. Dense samples fabricated from as-received powder demonstrated nominal UTS, yield, and elongation values at 260 MPa, 150 MPa, and 34%, respectively. The average electrical conductivity of these samples was measured at 95% of the international annealed copper standard (IACS). Samples fabricated from the oxidized powder exhibited nominal UTS, yield, and elongation of 241 MPa, 146 MPa, and 43%, respectively, with an electrical conductivity of 95% IACS. During characterization, it was observed that, rather than forming nano-scale dispersoids, the Zirconia (ZrO2) appeared as discontinuous stringers in the metallographic cross-sections that crossed grain and melt pool boundaries. This was rationalized by tracing the presence of the micro-alloying addition of elemental zirconium, which was found to react with surface oxides dissociated in the melt pool to form ZrO2, which then solidified on the surface of the melt pool through an allotropic transformation to monoclinic ZrO2 in discontinuous films and spheroids ranging in size from nanometers to microns. This was confirmed by microscopic analysis of the tops of the melt pools. On subsequent melt passes, these ZrO2 structures were displaced and redistributed within the melt pool.
10.1016-j.matchar.2023.112800	0	solidification; phase; magnetic; magnetic field; undercooling; field; liquid; separation; peritectic; immiscible; cu-; dendrite; phase separation; microstructure; primary	Applying cycle superheating and molten glass purification technologies, Cu55Ni45 and Cu55Ni43Co2 alloys were deeply undercooled to maximum undercoolings of 284 K and 250 K respectively. The microstructure characteristics and its evolution varying with bulk undercooling during the rapidly solidified process were analyzed. It was found that, after minor addition of element Co, refinement mechanisms of dendritic grain of the undercooled Cu-Ni-Co alloys was the same as those of the Cu-Ni alloys. Dendritic grain refinement occurring at low undercooling range was induced by dendrite breakup due to remelting, while the dominant factor of the grain refinement at high undercooling range was the recrystallization process. The driving force (i.e. stress induced strain energy) for recrystallization could be divided into two parts, one was the thermal stress generated by the releasing of solidification latent heat during the recalescence process, and the other was the accumulated stress and plastic strain caused by the interaction of liquid flow and primary dendrites caused by rapid solidification.
10.1016-j.matchar.2023.112863	10	composites; nanoparticles; strength; matrix; high; strengthening; particles; conductivity; composite; electrical; mpa; sintering; ods; grains; mechanical	High-performance Cu/graphene composites synergistically strengthened by nanoparticles were directly syn-thesized by hot press sintering using different organometallic substances, such as aluminum stearate, zinc stearate, and tetrabutyl titanate, as the graphene and nanoparticle formation source. The TiO2-doped Cu/Gra-phene composite possesses high hardness, great plasticity, and high electrical conductivity due to the uniformly -distributed three-dimensional (3D) network graphene and the TiO2 nanoparticles at the Cu/graphene interface. The composite wire processed by severe cold deformation without intermediate heat treatment displays high electrical conductivity of 92.3% IACS, great tensile strength of 497 MPa, and high softening temperature close to 400 degrees C, for which the graphene hinders the grain boundary movement and pins the dislocations, the TiO2 nanoparticles nail the interface and increase the roughness of graphene, the fibrous grains and the thinned graphene along the grain boundary provide a fast path for electron transmission. The present work offers a novel pathway for designing and fabricating high-performance Cu/Graphene conductors.
10.1016-j.matchar.2023.112958	15	aging; strength; conductivity; electrical conductivity; electrical; mpa; treatment; strengthening; degrees; cu-; cold; precipitation; tensile strength; tensile; iacs	Cu-Ti alloys were prepared by accumulative roll bonding-diffusion alloying process. The variation of electrical conductivity was investigated through the analysis of grain boundary evolution during the deformation-aging process, and the intrinsic mechanism was revealed. The results show that annealing twins formed inside the primary deformation-aged alloys, and the twin boundaries are mainly coherent sigma 3 grain boundaries. The density increases after secondary deformation-aging treatment and twin boundaries transform into incoherent ones. The electrical conductivity of 13.1% IACS is obtained for the alloy at a primary aging temperature of 350 degrees C and a secondary aging temperature of 315 degrees C. Higher primary aging temperature provides a driving force for the grain boundary evolution and the formation of coherent sigma 3 grain boundaries. The deformation treatment after primary aging treatment reconfigures the grain boundary strain distribution state and induces migration. The thermal effect of secondary aging process transforms coherent sigma 3 grain boundaries into incoherent ones. Lower secondary aging temperature improves the stability of incoherent I3 grain boundaries, reduces the percentage of random grain boundaries effectively and breaks the network connectivity. It decreases the energy decay degree of electron migration process and improves the electrical conductivity of alloys. The accumulative roll bondingdiffusion alloying process utilizes repetitive deformation and thermal effects to induce grain boundary evolution and regulate the types and content of special grain boundaries. It is an effective way to regulate the electrical conductivity of Cu-Ti alloys.
10.1016-j.matchar.2023.112996	-1		Carbon-doped CuFeMnNi multiple-principal-element alloys (MPEAs) were prepared via hot-forging and subsequent annealing at 900 degrees C for different durations varied from 15 min to 360 min. The annealed alloys exhibit dual face-centered-cubic (FCC) structures due to the immiscibility between Cu and Fe, and the microstructures remain thermodynamically stable after long annealing at such a high temperature. A large amount of FeMncarbides inside and at the edge of Fe-rich dendrite arm were still undissolved after annealing for 15 min and 120 min, which inhibited the growth of recrystallized grains in the region. In addition, most carbides dissolved during annealing at 900 degrees C for 360 min while the size of Cu precipitates increased with the increase of annealing time. Compared with the forged state, the as-annealed alloys exhibited good softening-resistant capability with the increase of annealing durations. The yield strength and ultimate tensile strength kept constant at 400 +/- 10 MPa and 800 +/- 30 MPa while ductility distinctly increased from 54% to 65%. Grain boundary strengthening, solid-solution strengthening and precipitation strengthening jointly contributed to the strength of the prepared alloys. The strengthening mechanism related to Cu precipitates gradually changed from shear mode to Orowan mode with increasing annealing time.
10.1016-j.matchar.2023.113038	7	irradiation; shear; grain; ta; deformation; size; radiation; voids; nanocrystalline; simulations; similar; void; temperature; irradiated; boundaries	Materials have been essential to every major invention in the history of mankind, e.g. satellites, nuclear reactors, or space shuttles would not exist without advancements in materials withstanding temperature and radiation environments. In this work, we investigate room-temperature implantations of helium and concurrent He and Au via in-situ transmission electron microscopy (TEM) followed by isochronal annealing up to 450 degrees C to understand the microstructural stability and bubble to cavity evolution in advanced nanocrystalline (NC) Cu-3 at%Ta and Cu-10 at%Ta alloys. The room temperature irradiation to high helium concentration and displacements per atom (dpa) levels did not lead to significant coarsening of grains in both Cu-10Ta and Cu-3Ta. Overall grain sizes remained <150 nm indicating extraordinary microstructural stability in both alloys. Post-irradiation, incubation for a few days resulted in the observation of similar to 1 nm diameter bubbles homogenously distributed in both the alloys and both irradiation conditions. Further evolution of these bubbles to cavities with annealing to 450 degrees C indicated Brownian motion migration and coalescence to be the dominant coarsening mechanism involved. A comparison of bubble to cavities evolution in Cu-3Ta and Cu-10Ta under similar conditions showed smaller bubble size and density in Cu-3Ta indicating an overall enhanced resistance of Cu-3Ta to swelling under both helium and dual-beam irradiation at high temperatures. This is primarily attributed to the high fraction of essential coherent/incoherent precipitates that act as effective defect sinks in Cu-3Ta.
10.1016-j.matchar.2023.113107	5	materials; thermal; heat; properties; material; welding; sintering; fusion; strength; laser; heat sink; thermal conductivity; mechanical; sink; manufacturing	Cu-Cr-based alloys with Cr content from 5 to 50 wt% are widely used as electrical contacts for vacuum in-terrupters for medium voltage applications because of their excellent combination of mechanical, thermal, and electrical conductivity. Cu-Cr electrical contacts are usually processed by sintering or casting processes. For solid-state sintered Cu-Cr materials, the physical properties vary as a function of the Cr content, phase morphology and porosity volume fraction. Some studies have investigated the effect of the microstructural characteristics of Cu-Cr alloys with different Cr content and morphology on their properties. However, the porosity characterization and Cr spatial distribution and how they affect these alloys' physical properties are not as well documented. In this study, we report an in-depth 3D characterization of the porosity and Cr-phase of solid-state sintered Cu-25Cr alloys with three final relative densities using X-ray Computed Tomography (XCT). An image analysis algorithm assisted by a machine learning-based segmentation method has been specifically developed. Results show that for Cu-25Cr solid sintered alloys there are mainly two types of pores, pores located at the Cu/Cr interfaces, and pores within the Cu matrix. The interfacial porosity represents the larger volume fraction, over 75% of the total porosity for all cases, forming a large network of interconnected pores. With the increase of final density, the Cu-matrix becomes nearly fully dense while interfacial pores still represent the largest fraction decreases in size and volume. These interfacial pores networks are believed to be formed due to poor filling and packing of Cu around the percolated Cr-phase. These observations might be helpful to optimize the functional properties of Cu-Cr sintered alloys.
10.1016-j.matchar.2023.113164	-1		The stability of the metastable & beta;'-Cu4Ti phase is a crucial factor for the electrical conductivity of Cu-Ti alloys. Determining the factors that influence the stability of the & beta;'-Cu4Ti phase and the relationship between the & beta;'-Cu4Ti phase and the electrical conductivity of Cu-Ti alloys is a prerequisite to improve their electrical con-ductivity. In this study, the stabilities of the & beta;'-Cu4Ti and & beta;-Cu4Ti phases were investigated by first-principles calculations combined with experimental characterization. When the Ti content of the & beta;'-Cu4Ti phase is greater than or equal to 19 at%, its stability is lower than that of the & beta;-Cu4Ti phase, resulting in instability of the & beta;'-Cu4Ti phase and dissolution of Ti atoms back into the Cu matrix. This is the main reason why it is difficult to improve the electrical conductivity of Cu-Ti alloys when the & beta;'-Cu4Ti phase is the main strengthening precipitate.
10.1016-j.matchar.2023.113213	-1		Plastic deformation usually improves the strength of Cu alloys by introducing high density dislocations and refined grains, but inevitably reducing electrical conductivity and ductility. Here we demonstrate that three exclusive properties, i.e., strength, conductivity, and ductility can be simultaneously enhanced in commercialized Cu-Cr-Zr plates through the well-controlled thermomechanical treatment. Very high strain cold rolling with a thickness reduction of 98% is applied, resulting in the formation of ultra-fine lamellar structures with an average size of 146 nm, which contributes to high tensile strength of 643 MPa. However, the elongation and electrical properties are poor. The subsequent aging treatment at a low temperature of 400 degrees C for 5 h introduces high density coherent Cr precipitates in those lamellar structures, while keeping the lamellar thickness almost unchanged. The aged Cu-Cr-Zr alloy exhibit high strength of 592 MPa, high conductivity of 86.8% IACS, and adequate elongation of 15.5%. This work proposes a strategy of overcoming the strength-ductility and strength conductivity trade-off relationships in industrial Cu products through the balanced manipulation of grain morphology and grain interior precipitation.
10.1016-j.matchar.2023.113264	-1		In this work, Cu-1.4 wt%Ta-Zr alloys with different Zr content (0, 0.1, 0.2 and 0.5 wt%) were fabricated by mechanical alloying combined with spark plasm sintering. The effect of Zr addition on the microstructures, mechanical properties and thermal stability of Cu-Ta alloy were characterized. Cu-Ta alloys composes of ultrafine equiaxed grains along with the uniformly dispersion of semi-coherent Ta nanoclusters and incoherent Ta coarse particles. As Zr is introduced into Cu-Ta alloy, the Ta precipitates were effectively refined, especially for the reduction of Ta coarse particles. The significant refinement effect of the grains is realized when Zr content reaches 0.2 wt%, and high-proportioned nano-sized grains are facilitated to form, along with the activation of a lot of twins and the formation of intermetallic composed of Cu and Zr. The dislocation density and strength increase remarkably with the increase of Zr content, and the highest strength (499 MPa for yield strength and 600 MPa for ultimate tensile strength) is achieved as the Zr content is up to 0.2 wt%. Compared with Cu-Ta alloy (382 MPa for yield strength and 560 MPa for ultimate tensile strength), the significant increment of 31% for the yield strength is successfully realized by Cu-Ta-0.2 wt%Zr alloy. Cu-Ta-0.2 wt%Zr alloys exhibit the excellent thermal stability, and the hardness keeps stable even the sample was annealed at 700 degrees C for 300 h, showing superior microstructural stability in comparison with Cu-Ta alloy (-4.5% reduction of the hardness after 300 h at 700 degrees C). The softening temperature of Cu-Ta-0.2 wt%Zr alloy is up to 1028 degrees C (1022 degrees C for Cu-Ta alloy) along with higher hardness than that of Cu-Ta alloy at the same annealing temperature. This study provides a new way to fabricate dispersion strengthened Cu alloys with high strength, exceptional thermal stability and softening resistance, which have great potential application value in the field of future fusion reactor.
10.1016-j.matchar.2023.113270	-1		Homogenization, random orientation, and high strength are the research goals of target materials. In this study, the bulk ultrafine-grained (UFG) Cu-5Mn alloy target materials were prepared by two typical severe plastic deformation methods, equal channel angular pressing (ECAP) and auxiliary-cooling multi-pass friction stir processing (MPFSP), and their structure-property relationships were comparatively investigated. Compared to the ECAP sample with extremely heterogeneous microstructure, the MPFSP sample exhibited finer and more uniform equiaxed microstructure with weaker texture and higher tensile strength of 614 MPa, which was consistent with the requirements of an ideal target material. This study provides a new perspective on the optimization of target materials.
10.1016-j.matchar.2023.113281	-1		This work presented a novel net-shape-forming technology to prepare oxide dispersion strengthened (ODS) copper by cold spray additive manufacturing. There were three types of Al2O3 particles in the internal oxidation Cu-Al2O3 raw powders. After cold spraying, two types of nano-sized Al2O3 inside the raw powder were inherited into the deposition, and the micro-sized Al2O3 on the powder surface was crushed to nano-size under severe plastic deformation, which dispersed along the interface of deformed powder due to the plastic flow of Cu caused by adiabatic shearing. The plastic deformation produced by cold spraying was 20% higher than the hot extrusion with extrusion ratio of 11:1, which fully achieves the Al2O3 fragmentation, dispersion distribution and densification of the cold sprayed deposition. Moreover, due to the significant work hardening and grain refinement effect by SPD during cold spraying, Vickers hardness and nanoindentation hardness of the ODS Cu deposition increased to 185.63 HV3 and 2.76 GPa, respectively, which were significantly higher than the raw powders and hot extrusion sample.
10.1016-j.matchar.2023.113293	14	strength; properties; conductivity; electrical; mechanical; cu-; grain; mpa; electrical conductivity; aging; precipitation; phase; mechanical properties; tensile; phases	The Cu-15Ni-8Sn-0.3Fe-xEr (wt%, x = 0.1-0.4) alloy was prepared by vacuum induction melting. The micro-structure evolution, mechanical properties and discontinuous precipitation (DP) growth kinetics during solidification and heat treatment were systematically investigated. The results show that the added Er leads to the formation of micrometer-sized ErNiSn2 phase and nanometer-sized ErNi phase in the Cu-15Ni-8Sn-0.3Fe alloy, which suppresses the formation of the discontinuous precipitation phases. Compared to alloys with other compositions, the Cu-15Ni-8Sn-0.3Fe-0.3Er alloy exhibits superior mechanical properties during aging at different temperatures. Specifically, after aging for 13 h at 723 K, the alloy achieved a peak hardness of 383.5 HV. In addition, the growth kinetics of the DP in Cu-15Ni-8Sn-0.3Fe-xEr (wt%, x = 0.1-0.4) alloys were evaluated using the Johnson-Mehl-Avrami-Kolmogorov equation. The activation energy (Q) of DP in the Cu-15Ni-8Sn-0.3Fe-0.3Er alloy is 178.4 kJ/mol, which is 39.2 kJ/mol higher than that of the Cu-15Ni-8Sn alloy.
10.1016-j.matchar.2023.113315	-1		Copper/aluminum (Cu/Al) composites with multifunctional applications have been extensively applied in a variety of fields. Nevertheless, the formability of Cu/Al composite strips during micro flexible rolling (MFR) has not been fully investigated in the sub-millimetre range. In the present work, the microstructure, mechanical properties and formability of Cu/Al composite strips during MFR were studied. The microstructure of the annealed and rolled specimens were characterized using scanning electron microscope (SEM) and electron backscatter diffraction (EBSD), and the thickness of Cu/Al composite strips with varying thickness (CSVT) was measured by laser scanning microscope. The results show that Cu/Al composite strips annealed at 400 degrees C exhibit the best ductility, and the CSVT with the best forming quality is obtained when the Cu layer is contact with the upper work roll. In addition, the microstructural evolution in the downward transition zone, thinner zone, up-ward transition zone and thicker zone with different reduction was discussed. When the plastic strain continues to increase from thicker zone to thinner zone, the intermetallic compounds (IMCs) layer generated during annealing breaks up, and subdivision and further refinement of Al grains occurs during MFR.
10.1016-j.matchar.2023.113325	15	aging; strength; conductivity; electrical conductivity; electrical; mpa; treatment; strengthening; degrees; cu-; cold; precipitation; tensile strength; tensile; iacs	It is a challenge to simultaneously improve the strength and plasticity of ultra-high strength and high elasticity copper alloys. A synergistic strengthening strategy of heterogeneous deformation-induced strengthening (HDI) and grain refinement strengthening is proposed. Cu-20Ni-20Mn-2Fe-1Si has been designed according to this strategy. The addition of Si formed G-phases (Mn6Ni16Si7) in the alloy, which have an average size of 1 mu m and a volume percentage of about 9.36%. There is a significant hardness difference between the Cu-rich phases and the G-phases, and the large strain gradient during deformation leads to HDI strengthening. After 75% cold rolling, solid solution at 830 degrees C for 2 h, and aging at 450 degrees C for 88 h, a large amount of NiMn phases of about 4-8 nm precipitated in the alloy and the average grain size is about 2.8 mu m. The tensile strength, yield strength, elastic modulus, and elongation of the alloy reached 1.37 GPa, 1.27 GPa, 149.4 GPa, and 6.04%, respectively. The calculation results show that precipitation strengthening, HDI strengthening, grain refinement strengthening, solid solution strengthening contribute 0.63 GPa, 0.45 GPa, 0.08 GPa, and 0.08 GPa to the total strength, respectively. All of these provide new ideas for the design of novel ultra-high strength and high elasticity copper alloys.
10.1016-j.matchar.2023.113346	-1		Based on micron atomized spherical Cu-18Sn-0.3Ti alloy powders, the Cu-18Sn-0.3Ti alloy with an elongation of 23.4%, an ultimate tensile strength of 507.2 MPa and a yield strength of 229.4 MPa was prepared using Direct Current assisted Hot Pressed sintering (DCHP) and conventional solution treatment. The microstructure evolution mechanism of alloy during DCHP, the strength-ductility synergy and fracture mechanisms of solution treated DCHP (ST-DCHP) samples were systematically investigated. The results show that, under the synergistic effect of Joule heat, electron wind force and external load of DCHP, dislocations were consecutively generated and consumed as the driving force of dynamic recrystallization, fine equiaxed grains and a large number of annealing twins were formed, the prior particle boundaries (PPBs) of alloy powders gradually disappeared and good sintering necks were formed, which played key roles in improving the strength of alloy. Simultaneously, the 8 phase was segregated from grain boundaries to PPBs during DHCP. During the subsequent solution treatment, the phase transformation of 8 phase occurred, the 13, gamma and e phases which were conducive to the plastic deformation of alloy were generated inside 8 phase, resulting in a change in the fracture mechanism inside powders and at sintering necks. The high fraction of high-angle grain boundaries (HAGBs) was considered as the main reason for inducing the formation of high-density deformation twins with different directions inside fine alpha grains, which greatly improved the ductility of alloy. The strengthening contributions of microstructure were also evaluated, and the calculated yield strength was well consistent with the experimental ones. The results provide the theoretical guidance for the preparation of Cu-Sn-Ti alloy with higher Sn content and lay a foundation for the preparation of Nb3Sn superconducting wires with higher critical current density.
10.1016-j.matchar.2023.113413	-1		Bicrystals serve as a simplified model system for studying the deformation behavior of polycrystalline materials. In this study, we fabricated graphene nanosheets (GNSs) reinforced copper (Cu) matrix laminated composites using electrophoretic deposition and subsequent vacuum hot-press sintering. Interestingly, the composite exhibited a bicrystal microstructure, with two types of adjacent crystals, i.e., denoted as crystal A (phi 1 = 222.06, phi = 40.54, phi 2 = 82.5) and crystal B (phi 1 = 141.36, phi = 43.76, phi 2 = 1.94), displaying a twin orientation relationship. To investigate the deformation behavior of the GNS/Cu composite, we conducted interrupted room temperature uniaxial tensile tests combined with Scanning Electron Microscope (SEM) Electron Backscatter Diffraction (EBSD) characterization. To identify the activated slip systems in the composites, we performed trace analysis, applied the Schmid Factor law, analyzed the deformation gradient tensor, and conducted intragranular misorientation axis (IGMA) analysis. The trace analysis revealed that slip systems with high Schmid Factor values were favored during tension. Moreover, the deformation gradient tensor elements of the primary slip systems in the two crystals confirmed the deformation features observed by SEM. However, crystal B exhibited a significant deviation in trace angle. Further IGMA investigation revealed that during tension, some slip systems, which were not favored by the Schmid Factor law, were also activated in crystal B. The activation of these slip systems in crystal B can be attributed to the large deviation in the trace angle. The findings in this work provide valuable insights for exploring the underlying deformation mechanisms in polycrystalline materials.
10.1016-j.matchar.2023.113469	-1		The effect of cryogenic rolling and intermediate aging on the microstructure and properties of the Cu-10Fe-1Nb composites were investigated. After aging for 1800 min, the microhardness, tensile strength and elongation of the Cu-10Fe-1Nb samples reached 158 HV, 623 MPa and 22%, respectively. The microstructure results showed that the fibrous Fe-rich phases and the matrix of the Cu-10Fe-1Nb samples were refined significantly after cryogenic rolling. It could be attributed to the increasing shear strain between the Fe-rich phases and matrix with dislocation density of the matrix, which inhibited the dynamic recovery recrystallization of the matrix. The intermediate aging promoted the dissolved Fe to precipitate obviously, and these precipitates effectively impeded the recrystallization of the matrix during the subsequent aging process. The improvement of mechanical properties was mainly attributed to the Orowan strengthening, refinement strengthening and work hardening resulted from the numerous precipitates, fine grains and high-density dislocation in the matrix, respectively.
10.1016-j.matchar.2023.113513	-1		Cu features excellent electric conductivity, although typically at the expense of favourable mechanical properties. Nevertheless, by optimizing the processing procedure, the mechanical properties can be enhanced while maintaining advantageous electric conductivity, which consequently increases the efficiency of copper wires and leads to their lower weight, as well as lower costs of material and production. The presented study investigates the effects of a thermomechanical manufacturing procedure involving rotary swaging, an industrially applicable intensive plastic deformation method imparting shear mixing and intensive (sub)structure modifications, performed at cryogenic conditions on the microstructures and mechanical and electric properties of Cu conductors. The results showed that the cryogenic swaging resulted in formation of significantly elongated grains with heavily refined cross-sections, which featured the mechanical properties enhanced by almost 200%, and, simultaneously, the electric conductivity of 104.9% IACS (International Annealed Copper Standard). By applying an optimized heat treatment, the electric conductivity even increased to 105.8% IACS, primarily due to structure homogenization and development of twins in the micro, and also nano scales.
10.1016-j.matchar.2023.113533	-1		Sulfur (S), as the common impurity prevalent in copper (Cu) and Cu-based alloys, often induces the intergranular embrittlement at intermediate temperatures even with a ppm concentration, a phenomenon variously called intermediate temperature embrittlement (ITE). However, the inhibition of such an embrittlement has been rarely reported. In this study, we investigate the influence of trace cerium/ yttrium (Ce/Y) addition on the ductility of the ultrahigh-purity Cu containing minute amounts of S impurities at temperatures between room temperature (RT) and 900 degrees C. The results show that both Ce and Y additions can improve the ductility of the Cu-S alloy at any test temperature, which is attributed to the inhibition of Ce/Y on the grain boundary (GB) segregation of S by forming the RE-S precipitates. By comparison, the modification of ITE caused by S impurities is not significant after trace Ce is introduced, while the addition of small amounts of Y can completely eliminate the ITE phenomenon at temperatures of 300-750 degrees C. This results from the size of the RE-S precipitates and the structure of the transition nanolayers between the RE-S precipitates and Cu matrix, which is dependent on the diffusion rates of the dissolved S, Ce and Y atoms in Cu during the tensile deformation. Our findings provide a comprehensive experimental and computational understanding on the fundamental mechanisms of rare earth elements inhibiting the embrittlement induced by impurities in metallic materials.
10.1016-j.matchar.2023.113557	15	aging; strength; conductivity; electrical conductivity; electrical; mpa; treatment; strengthening; degrees; cu-; cold; precipitation; tensile strength; tensile; iacs	A Cu-0.4Cr-0.39Zn-0.1Mg-0.07Zr (wt%) alloy was prepared using cryogenic rolling process and multistage thermo-mechanical treatment to achieve excellent comprehensive properties with tensile strength of 635 MPa, yield strength of 620 MPa and electrical conductivity of 75.3% IACS. A large number of nano deformation twins appeared in the alloy after cryogenic rolling, and the width of the nano twins decreased with the deformation, and the average width of nano twins decreased by 8.4% and 11.8% after the second and the third cryogenic rolling, respectively. The high density of dislocations introduced by cryogenic rolling provided more nucleation sites for Cr phase precipitation, which promoted the diffusive precipitation of Cr phase. With the synergy of microalloying of Mg and Zn elements, cryogenic rolling and multistage thermo-mechanical treatment, the copper alloy with high density of nano deformed twins, fine and diffuse precipitation phases and excellent performance was prepared, which can be used as high-performance copper alloys for lead frames of large-scale integrated circuits.
10.1016-j.matchar.2023.113601	15	aging; strength; conductivity; electrical conductivity; electrical; mpa; treatment; strengthening; degrees; cu-; cold; precipitation; tensile strength; tensile; iacs	In the Cu-2.5Fe-0.3Cr-0.3 Mg-0.2Si-0.1Ca-0.1Zr alloy, a double-scale (micro and nano) FeCrSi second phase has been generated. The orientation relationship between nano-precipitates and the matrix is: (111)Cu//(202) FexCr(3-x)Si, [110]Cu//[111] FexCr(3-x)Si. The influence of the thermomechanical treatment process on the microstructure, mechanical properties and electrical conductivity of the alloy is explored. Results indicate that the final alloy has excellent properties. The hardness, yield strength, tensile strength and electrical conductivity of the final alloy are 204 HV, 635 MPa, 649 MPa and 63.57 %IACS, respectively. The calculations show that precipitation strengthening and dislocation strengthening have essential contributions to the strength of the final alloy. The former mainly comes from the strengthening effect of the FeCrSi nano-precipitates, and the latter is related to the multi-stage thermomechanical treatment process.
10.1016-j.matchar.2024.113681	-1		The manufacture of high strength, high electrical conductivity, and high ductility of Cu-Ni-Si strips in the industry is a challenging problem due to the mutually exclusive relationships among the three properties. However, the results obtained in the present study demonstrated that the trade-offs can be improved by employing a multi-pass continuous extrusion and aging process. The mechanical strength and electrical conductivity increase with the increase of extrusion number before three passes with the help of dynamically occurred recrystallization and precipitation. The yield strength, however, drops after four-pass extrusion, suggesting that a too-high strain deformation during continuous extrusion is not favorable. After aging, alloys that suffer fewer extrusion passes exhibit higher yield strengths, indicating that it is the precipitates rather than the microstructure that dominates the mechanical properties of Cu-Ni-Si alloys. Interestingly, the fracture elongation after aging for alloys experienced more pass number increases, which can be attributed to the refined grain size and reduced dislocation densities. After a two-pass continuous extrusion and aging process, the tensile strength and fracture elongation can reach 629 MPa and 16.5%, respectively, increasing approximately by 28.8% and 13.4% compared with those before aging. It is therefore significant to design an appropriate deformation process (strain) for continuous extrusion to obtain high strength, high conductivity, and high ductility Cu-Ni-Si strips.
10.1016-j.matchar.2024.113693	-1		6-Ni2Si precipitate is the crucial strengthening phase in Cu-Ni-Si alloy, and its coarsening behavior and mechanism impose dramatic effects on mechanical properties. In this paper, Cu-3Ni-0.7Si-0.1Cr-0.05 Mg (wt%) alloy was prepared to systematically investigate the coarsening behavior and elucidate the coarsening mechanism of 6-Ni2Si precipitate during over -aging treatment. Featured core -shell structure was observed via careful characterization during coarsening of 6-Ni2Si phase. Specifically, the core structure was stable 6-Ni2Si, while the shell structure was a metastable interface composed of Cu, Ni and Si elements. At later over -aging stage, the core -shell structure completely transformed into a stable and coarsened 6-Ni2Si phase being coherent with the Cu matrix. It is confirmed for the first time that the coarsening process of 6-Ni2Si precipitate can be interpreted by the transinterface -diffusion -controlled (TIDC) coarsening theory. The core -shell structure was caused by the disparity between the diffusion activation energy and diffusion rate of Ni, Si, and Cu from the perspective of diffusion kinetics. Moreover, the presence of trace amounts of Cr and Mg components exhibited little effect on the coarsening process of 6-Ni2Si. During over -aging, tensile strength dramatically decreased owing to diminishing precipitation strengthening effect from coarsening of 6-Ni2Si precipitates.
10.1016-j.matchar.2024.113711	-1		Cu-Fe alloys with high iron content (Fe > 10 wt%) are a class of promising copper alloys with high strength and high conductivity. However, the strength and conductivity trade-off dilemma is a longstanding problem in the high iron content Cu-Fe alloys owing to macro-segregation of iron particles and incomplete precipitation of solid solution iron atoms in the traditional casting process. We adopted a comprehensive strategy of designing the ultra -fine dual structures with fine copper grains and micro-nano iron particles, and adding phosphorus element to induce solid solution iron atoms precipitation to break through the above bottleneck. In this study, Cu-20Fe alloys with 0.05-1.0 wt% P were prepared through powder metallurgy process. The results showed that the addition of P promoted the precipitation of soluble Fe atoms, reduced oxygen content, and activated sintering. Ultimately, the strength and conductivity of cost-effective Cu-20Fe alloys were significantly improved. The annealed Cu-20Fe-0.1P alloys possess unprecedented comprehensive properties with 608 MPa tensile strength and 65.2% IACS electrical conductivity, which were 7.8% and 19.8% higher than the Cu-20Fe alloys, respectively. The annealed Cu-20Fe-1.0P alloys achieved 59.7% IACS electrical conductivity, increased by 10% compared to Cu-20Fe alloys. The results broke the conventional understanding that increasing P content deteriorated material properties. The influence of P on the microstructure and properties of powder metallurgy Cu-20Fe alloys was investigated in detail. These findings provide new insight into overcoming the dilemma of the inverted relationship between the strength and conductivity of copper alloys.
10.1016-j.matchar.2024.113781	15	aging; strength; conductivity; electrical conductivity; electrical; mpa; treatment; strengthening; degrees; cu-; cold; precipitation; tensile strength; tensile; iacs	Cu-Fe alloy wire is widely used in the field of electronic information because of its high strength and high conductivity. In this study, Cu-5Fe-0.1Si-0.3 Mg-0.05RE (La, Ce) alloys were prepared by cold drawing and heat treatment. The microstructure evolution of the alloy during deformation was studied by optical microscope, scanning electron microscope (SEM) and transmission electron microscope (TEM). Three kinds of second phases with different sizes and shapes were successfully constructed in the designed alloys, including fibrous iron phase, submicron spherical iron phase and nano spherical phase. The strength of the alloy is greatly improved by drawing deformation, with only slight reduction of the conductivity. Through joint addition of Mg, Si and rare earth elements, the designed Cu-Fe alloy wire rod has excellent overall properties. It's electrical conductivity, tensile strength, yield strength and elongation reached 63.8% IACS, 831 MPa, 730 MPa and 6.1%, respectively. Detailed characterizations of the alloys reveal that: the addition of Mg reduces solid solubility limit of iron in matrix and spaces between iron phases; the FeSi phase formed by Si and Fe promotes the precipitation of iron phase; and the addition of rare earth inhibits segregation of second phase, recovery and recrystallization of the alloy, and the coarsening of Fe phase. The mechanical properties of the alloy are improved by fiber strengthening, Hall-Petch strengthening and precipitation strengthening, respectively. The contributions of precipitation strengthening, fiber strengthening and Hall-Petch strengthening to yield strength are 65 MPa, 59 MPa and 277 MPa, respectively. The microstructure of dislocation and fibrosis is the main factor of alloy strengthening.
10.1016-j.matchar.2024.113796	15	aging; strength; conductivity; electrical conductivity; electrical; mpa; treatment; strengthening; degrees; cu-; cold; precipitation; tensile strength; tensile; iacs	A Cu-15Ni-8Sn alloy ingot was prepared in a medium-frequency induction melting furnace. First, the hot extruded alloy was subjected to solution treatment at 840 degrees C for 60 min, after which cold drawing treatment was applied under different deformation conditions (0-70%). Finally, the cold-deformed alloy was subjected to aging at different temperatures (340-520 degrees C) and insulation times (0-480 min). The evolution of grain characteristics, micromorphology and mechanical properties during cold drawing deformation and aging were systematically studied. The results show that during cold drawing deformation, the grains in the solid solution Cu-15Ni-8Sn alloy gradually elongate along the drawing direction with increasing deformation, and the texture changes from a discrete distribution to a hard orientation. Cold drawing deformation promoted coarsening of the modulated structure and the transition of the D0(22) ordered phase. Dislocations and twins increased the occurrence of nucleation for the discontinuous precipitates and promoted the growth of the discontinuous precipitates, but cold deformation inhibited the transition of the D0(22) ordered phase to the L1(2) ordered phase. The hardness, tensile strength and elongation of the Cu-15Ni-8Sn alloy after 50% cold deformation were 109.2 HRB, 1258.3 MPa and 7.5%, respectively, after aging at 400 degrees C for 60 min. The main strengthening mechanisms of the peak-aged alloy were precipitation strengthening and dislocation strengthening.
10.1016-j.matchar.2024.113912	-1		The distribution of second-phase particles is crucial to the mechanical properties of particulate reinforced copper matrix composites (PRCMCs). Ultrasonic vibration treatment (UVT), as an effective technique to disperse secondphase particles in metallic melts, has been extended to treat PRCMCs using a SiAlON sonotrode. In this study, systematic experiments have been conducted to explore the effect of UVT on the microstructures and mechanical properties of in situ Cu-TiB 2 composites. The results indicated an optimal duration of UVT for 3 min, featured by an improved distribution of TiB 2 particles and superior mechanical properties of the as-cast composite. The ultimate tensile strength, yield strength, and elongation exhibited significant increases of 15.7%, 18.1%, and 36.1%, respectively, compared to the as-cast Cu-TiB 2 composite without UVT. Furthermore, these experimental composites were subject to rolling deformation. The results once again demonstrated that the as -rolled Cu-TiB 2 composite, treated with UVT for 3 min, stood out as the best. The ultimate tensile strength, yield strength, and elongation of the as -rolled Cu-TiB 2 composite were 459 MPa, 422 MPa, and 7.0%, respectively. Based on the microstructural observation, the mechanism underlying the UVT-induced enhancement of mechanical properties was discussed in terms of the non-linear effects of ultrasound cavitation on liquid metals. This work can provide a strategy for producing high-performance PRCMCs through UVT.
10.1016-j.matchar.2024.113961	-1		In this manuscript, the CuxNiTiCr (x = 2, 3, 4, 5) series medium-entropy alloys (MEAs) were produced by nonconsumable vacuum arc melting furnace and the effects of Cu contents on the microstructures, phases and mechanical properties were studied. The results show that the CuxNiTiCr (x = 2, 3, 4, 5) series MEAs are mainly composed of FCC, BCC1 and BCC2 phases. With the increase of Cu contents, the dendrites are refined and the amount of FCC phase increases. The strength of the alloys decreases with the increase of Cu content, but the ductility of the Cu5NiTiCr is the highest. With the increase of Cu content, the vickers hardness of the alloy decreases, while the hardness value does not change when the x exceeds 4. The Cu2NiTiCr and Cu3NiTiCr MEAs also have good wear resistance.
10.1016-j.matchar.2024.114007	14	strength; properties; conductivity; electrical; mechanical; cu-; grain; mpa; electrical conductivity; aging; precipitation; phase; mechanical properties; tensile; phases	Controlling discontinuous precipitation is crucial for improving the microstructure and mechanical properties of Cu-Ni-Sn alloys. Through the utilization of various characterization techniques such as transmission electron microscopy, scanning electron microscopy, optical microscopy, and mechanical testing, we have successfully demonstrated that the introduction of either Ti or a combination of Fe and Ti elements effectively inhibits the formation of discontinuous precipitation. Notably, the combined addition of Fe and Ti elements showcases superior suppression of the discontinuous precipitation structure. Consequently, we have developed a novel alloy, namely Cu-15Ni-7.5Sn-0.5Fe-0.5Ti, which exhibits remarkable resistance to over-aging. Our analysis indicates that the mechanism of inhibiting discontinuous precipitation is multifaceted. The main effect is believed to be the reduction in nucleation sites and the pinning effect of the D024-Ni3Ti phase on grain boundaries, resulting in a significant decrease in the nucleation rate and growth of the DP reaction. The secondary impact may be due to the distribution of D024-Ni3Ti phase at grain boundaries, which leads to a decrease in grain boundary energy. Meanwhile, the formation of D019-Ni3Sn phase reduces the chemical driving force required for DP growth .
10.1016-j.matchar.2024.114029	-1		This study investigates the influence of torsional deformation with different equivalent strains on the microstructural evolution and mechanical properties in pure copper at room temperature. The grain size exhibits a gradient distribution pattern with decreasing shear strains. Texture analysis reveals the development of a typical torsion texture during deformation. And the texture component is significantly influenced by the strain level. In samples subjected to low strain at the center position, the dominant texture components are mainly A and A* components. As strain increases in the 1/4 layer sample region, there is a gradual decrease in strength for A* component, while A component remains dominant; additionally, B and C textures exhibit increased strength . At positions subjected to maximum strain near the surface area, B texture replaces A as the strongest texture component. Results also indicate that torsional deformation enhances hardness, strength, and plasticity due to dislocation strengthening, fine grain strengthening and synergistic effects during deformation. Furthermore, the formation of torsional texture during this process may contribute to improved plasticity.
10.1016-j.matchar.2024.114065	-1		The effect of Mg/Ca/Nb/Ag alloying on the morphology and microstructure of powder metallurgy Cu10Fe alloy was investigated systemically in this work. Alloying of Ca reduces the size of Fe-rich particles, while alloying of Mg/Nb/Ag increases the Fe-rich particles. This is attributed to the different roles of various alloying elements on the liquid-phase separation behaviors as well as diffusion of Fe atoms during the solidification. Coarse size spherical Fe-rich particles with a face centered cubic structure are observed in Cu-Fe alloys bearing Mg/Ag/Nb, whilst the alloying of Ca favors the formation of fine spherical Fe-rich particles with a body centered cubic structure. The factor governing the morphology is found to be interfacial energy for Cu-Fe alloys containing Mg/Ag/Nb and elastic energy for Cu-Fe-Ca alloy, respectively. Coarse size Fe-rich particles are hard to deform during subsequent rolling, but the fine Fe-rich particles can co-deform with Cu matrix. This study could provide a detailed picture regarding the influence of various alloying element types on the size, morphology, and lattice structure of Fe phase of Cu-Fe alloy.
10.1016-j.matchar.2024.114104	-1		The characterization of forming limit utilizing Cu-Cr-Zr-Ti alloy sheets during the multistage forming process is imperative for successfully fabricating thrust chamber liners used in satellite launch vehicles. Therefore, the present work studies the effect of prestrain on the forming limit and failure behaviour of this alloy under different deformation paths. A stretch-forming setup was utilized to induce 8% equi-biaxial prestrain (EBP), and subsequently, these prestrained specimens were deformed till the onset of failure using the same setup. After prestraining, a shift in the failure strains was observed in the principal strain space, whereas it was found to be absent in the polar effective plastic strain, principal stress and effective plastic strain-stress triaxiality loci. The cup height along different deformation paths was marginally decreased in the prestrained specimens because of the reduction in failure strains, and the fracture occurred in the prestrained region. Further, failure analysis revealed intergranular cracks in the specimens deformed along plane strain and uniaxial deformation paths due to the presence of micron-size Cr-rich precipitates along grain boundaries. However, intergranular and transgranular cracks were present in the prestrained specimens, which were deformed equi-biaxially similar to the asreceived specimens. The presence of nano-size Cr-rich precipitates inside the grains acted as nucleation sites for voids during equi-biaxial stretching, leading to transgranular cracks. It was also observed that failure in the prestrained and as-received specimens occurred at a similar effective plastic strain value due to the combined effect of void density and void size. Based on experimental observations, it was inferred that the forming limit of Cu-Cr-Zr-Ti sheets under a two-stage forming process was primarily affected by the presence of micro and nanosize Cr-rich precipitates.
10.1016-j.matchar.2024.114110	-1		In this paper, the intermetallic compound ZrTe2 phase is formed within a copper matrix by data-driven elemental screening. This low melting point ZrTe2 phase is uniformly and diffusely distributed within the copper matrix, which avoids the need for an energy-intensive process while providing superior resistance to arc ablation. On this basis, a novel Cu-0.6Te-0.3Cr-0.15Zr-0.008P alloy is designed and prepared, and the alloy achieves an electrical conductivity of 95.7 %IACS, a tensile strength of 302 MPa, and an elongation of 39.53% after the thermomechanical treatment. The ablation current of the novel alloy under large voltage is 31.2% lower than that of the Cu-0.6Te alloy, and the cross-sectional area of the ablation traces is reduced by 85%, which effectively illustrates the substantial improvement of the novel alloy's ability to resist arc ablation. There are ZrTe2 phases of 0.5-2 mu m as well as pure Cr phases of about 5-20 nm in the alloy. The ZrTe2 phases absorbs heat through melting decomposition to achieve arc extinction, and the Cr phases pinning dislocations to promote strength enhancement. In addition, the synergistic addition of Cr and Zr plays a role in the grain refinement of the alloy, and the average size of the grains decreases from 4.2 mu m to 3.1 mu m, a decrease of 26%, under the same process. This novel CuTe alloy with high strength, high conductivity and high resistance to arc abrasion is easy to produce and low energy consumption, and is expected to be widely used in the new generation of high-voltage fast-charging electrical connector materials for new energy vehicles.
10.1016-j.matchar.2024.114140	15	aging; strength; conductivity; electrical conductivity; electrical; mpa; treatment; strengthening; degrees; cu-; cold; precipitation; tensile strength; tensile; iacs	Cu-Cr-Nb alloys has become a key material for ITER plasma facing components (PFC) due to its excellent thermal stability. In this study, Cu-3.3Cr-1.6Nb (wt%) alloy was prepared through in-situ casting using Cu-Cr and Cr-Nb master alloy. The agglomeration and coarsening of Cr2Nb particles in Cu-Cr-Nb alloy are improved. The effect of aging temperature on the microstructure and properties of rolled Cu-3.3Cr-1.6Nb alloy. The results show that the aged Cu-3.3Cr-1.6Nb alloy contains multi-scale precipitation phases distribution with micron-level Cr2Nb (0.2-2 mu m), Cr-rich phase (2.2 mu m), nano-level Cr2Nb (13.1 nm) and nano-level Cr (9.3 nm). After aging at 450 degrees C for 0.5 h, the tensile strength and electrical conductivity of the aged alloy were 469 MPa and 78.5% IACS, respectively. According to TEM and EBSD analysis, the Cr2Nb particles did not grow during the aging and were pinned the grain boundaries to inhibit the growth of Cu matrix grains, which result in a good thermal stability of Cu-3.3Cr-1.6Nb alloy. This study provides a new method for preparing Cu-Cr-Nb alloy with high-strength, high-conductivity and high heat resistance by casting method.
10.1016-j.matchar.2024.114198	14	strength; properties; conductivity; electrical; mechanical; cu-; grain; mpa; electrical conductivity; aging; precipitation; phase; mechanical properties; tensile; phases	Copper alloys are utilized either as cast or wrought alloys. Typically, cast alloys contain a higher quantity of elements to enhance strength . The increased content of additive elements inevitably escalates the precipitation driving force. However, this can result in heterogeneous nucleation, leading to the formation of large particles at grain boundaries, consequently impeding the strengthening process. Managing the shape and structure becomes pivotal to address this challenge. The Cu alloy, enriched with 6 wt% Ni, 1.3 wt% Si, and 2.4 wt% Mn, possesses a high precipitation driving force due to the abundance of solutes in the matrix at high temperature. Upon cooling in air following heat treatment at 980 degrees C for 8 h (homogenization), both homogeneous and heterogeneous nucleation and growth processes occur within the grain interior and at the grain boundaries. The phase heterogeneously formed at the grain boundary is identified as Ni2Si compound in the Cu-Ni-Si alloy, while the phase at the grain boundary is recognized as Mn6Ni16Si7, known as the G-phase. The presence of G-phase at the grain boundary results in higher strength and ductility compared to the alloy with Ni2Si. The substantial coverage of the grain boundary by the film-shaped G-phase renders the grain boundary more stable than the irregularly shaped Ni2Si, consequently contributing to the elevated strength and ductility of the Cu-Ni-Si alloy.
10.1016-j.matchar.2024.114225	-1		The effect of friction-stir processing (FSP) and the subsequent aging treatment on the microstructure, electrical conductivity, and mechanical properties of a Cu-0.3%Cr-0.5%Zr alloy was studied. FSP promoted complex microstructural changes, including significant grain refinement and dissolution of secondary particles within the stir zone and particle coarsening within the heat-affected zone. The particle phenomena resulted in the essential material softening and degradation of electrical conductivity. The subsequent aging treatment provided particle reprecipitation within the stir zone and thus essentially recovered material properties in this area. In the heataffected zone, however, the recovery effect was less pronounced, thus leading to the characteristic W-shaped profiles of microhardness and electrical conductivity. This result was attributed to the insufficient degree of supersaturation of the solid solution in this microstructural region, which, in turn, promoted the relatively slow precipitation kinetics.
10.1016-j.matchar.2024.114304	-1		By changing the cooling rate and adding P element, the morphology of primary Ni16Ti6Si7 in hypereutectic Cu-Ni-Si-Ti alloy has been analyzed in detail, and its growth mechanism has been discussed. Increasing the cooling rate can enhance the nucleation and growth of the primary phase. However, excessive cooling rates may result in constitutional supercooling, leading to the primary phase exhibiting various shapes. During the growth process, the crystal will preferentially grow along the < 100 > direction, and eventually cause the {100} facets to degenerate into corners, while the {111} facets retain and forms the octahedral Ni16Ti6Si7 due to the lower growth rate. Meanwhile, when the external growth conditions are changed, such as adding P element, the relative growth rate of <1 0 0 > and < 111 > directions will be changed, and the {1 0 0} facets will eventually remain and form cubic Ni16Ti6Si7.
10.1016-j.matchar.2024.114308	-1		Coherent gamma '-phase precipitation strengthened heat-resistant Cu-based alloys exhibit promising application in the field of high-temperature. In the work, to further improve the comprehensive performance of the alloys, the elements Cr, Zr, Zn and Ti are introduced into the model alloy (Cu83.33Ni12.50Al4.17 at%). The existence state of the adding elements and their influence on comprehensive properties, including the in-situ high-temperature hardness, tensile properties and stability, etc., was unveiled. Furthermore, the Cu83.33Ni11.11Al2.78Cr1.04Ti1.04Zr0.35Zn0.35 alloy with excellent comprehensive properties was designed and prepared, exhibiting a high-temperature tensile strength of 370 MPa and an elongation of 3.7 % and high temperature stability of up to 400 h at 873 K. The reasons for the improvement of comprehensive properties can be attributed to the following aspects: (1) The adding elements not only inhibit discontinuous precipitation but also refined the size of the gamma' phase and improved its thermal stability; (2) Cr and Zr inhibit the precipitation of deleterious D0(24)-Ni3Ti phase caused by Ti; (3) The BCC-Cr (precipitation strengthening phase) and Ni5Zr phases (grain boundary strengthening phase) are introduced. This study successfully demonstrates the advantages of addition of multiple-elements through regulating their interaction, thereby establishing a robust foundation for designing heat-resistant Cu-based alloys in future investigations.
10.1016-j.matchar.2024.114334	-1		The microstructure and mechanical properties of Cu-12.5Ni-5Sn-xY alloys with different Y addition amounts prepared using spark plasma sintering (SPS) were investigated, and the relationship was discussed. Results indicate that the addition of Y could significantly improve the mechanical properties. When 0.4 wt% Y is added, the maximum hardness and yield strength are approximately 329.5 HB and 691.9 MPa, which are approximately 31 % and 48 % higher than that without Y, respectively. The addition of appropriate amount of Y can significantly refine the grains, promote the transformation of gamma-phase in the alpha + gamma coexisting structure from lamellarshape to needlelike-shape, and significantly inhibit the nucleation and growth of discontinuous precipitation (DP). Especially, when 0.4 wt% Y is added, the nano-scale NiY3 particles precipitated at the grain boundary can hinder the migration of the grain boundary and occupy the nucleation sites of the gamma-phases. In general, grain refinement, nano-precipitation strengthening and inhibition of DP are the main reasons for the improvement of mechanical properties.
10.1016-j.matchar.2024.114386	-1		In this work, the resistance against nanoindentation of the Laser Powder Bed Fusion (LPBF) CuCrZr alloy specimen was studied at the ramp load of 2000-3000 mu N on 100 points. It was found that the triangular shape indentation cavity and the pile-up material increased along the diagonal direction. The LPBF CuCrZr alloy contained few partly melted LPBF particles which have three different structures namely columnar, cellular and equiaxed. The nanowear test was conducted on the above three structures. The tribological property of partly melted LPBF particles was analyzed at 2000 mu N cyclic load. The wear depth in the partly melted LPBF particles at the columnar structure for cycle-1, cycle-2 and cycle-3 were 836 nm, 918 nm and 980 nm, respectively. The wear depth in the partly melted LPBF particles at the cellular structure for cycle-1, cycle-2 and cycle-3 were 650 nm, 780 nm and 810 nm, respectively. The wear depth in the partly melted LPBF particles at the equiaxed structure for cycle-1, cycle-2 and cycle-3 were 650 nm, 720 nm and 780 nm, respectively. The obtained outcomes were correlated with the tribological behavior of non-defective part. The non-defective part exhibited higher wear resistance than the partly melted LPBF particles. The percentage increase in wear resistance at the columnar nondefective part over partly melted LPBF particles for cycle-1, cycle-2 and cycle-3 were 22.24 %, 20.5 % and 20.4 %, respectively. Similarly, the cellular and equiaxed non-defective parts have higher wear resistance when compared to the partly melted LPBF particles. Moreover, the decrease in Coefficient of friction was observed from one cycle to the next cycle both in the partly melted LPBF particles and non-defective part in all three structures.
10.1016-j.matchar.2024.114387	-1		In current work, the effect of nanoparticle size in Cu-Y2O3 alloy on the microstructure response after He/D sequential irradiation is studied using a transmission electron microscope (TEM) and nanoindentation. The results indicated that the direct contribution of nanoparticle/matrix interface to defect evolution and irradiation hardening of ODS Cu is limited when the nanoparticle size is larger than 20 nm. The difference in the proportion of & sum;3 grain boundary and small angle grain boundaries was observed with different nanoparticle sizes, which suggests that the indirect effects on the sink strength caused by changes in the nature of grain boundary cannot be ignored, especially for the large particles. Besides, the distribution of bubbles after sequential He/D irradiation was highly similar to that in single He irradiation.
10.1016-j.matchar.2024.114388	15	aging; strength; conductivity; electrical conductivity; electrical; mpa; treatment; strengthening; degrees; cu-; cold; precipitation; tensile strength; tensile; iacs	The Cu-Ti alloy is extensively utilized for its high strength, excellent elasticity, and processability. Heat treatment processes are crucial for affecting the microstructure and properties. The effects of different aging processes on the microstructure and properties of cold-rolled Cu-Ti-Fe alloy were investigated, and the heat treatment parameters were optimized. The results show that the cold-rolled Cu-Ti-Fe alloy exhibits excellent comprehensive performance at 450 degrees C for 2 h, with the hardness of 342.2 HV, the electrical conductivity of 16.1 % IACS, and the tensile strength of 1051 MPa. The aggregation of solute atoms occurs in the early stages of aging. The uniformly distributed beta'-Cu-4 Ti phase precipitates at peak aging, which has a coherent relationship with the matrix. The precipitation of Ti atoms enhances the electrical conductivity of the alloy, and the movement of dislocations is prevented by precipitates, increasing the strength . During the over-aging stage, the precipitates transform into beta-Cu-4 Ti phases, losing complete coherency with the matrix. The coarsening of precipitates leads to the softening of the Cu-Ti-Fe alloy. Theoretical calculation results indicate that the thermal diffusion ability of solute atoms is the strongest and precipitates completely when the alloy aged at 450 degrees C. The precipitation strengthening mechanism plays a significant role in improving the strength .
10.1016-j.matchar.2024.114426	15	aging; strength; conductivity; electrical conductivity; electrical; mpa; treatment; strengthening; degrees; cu-; cold; precipitation; tensile strength; tensile; iacs	The Cu-Cr-Nb alloy's high-temperature property is well known for the heat-sink application in rocket engine combustion chambers. Effects of Ti, Si, and Co microalloying elements on the microstructure and mechanical properties at high temperatures were investigated in detail. Cu-Cr-Nb alloy ingots were prepared using the atmospheric melting method and the growth rate of Cr precipitates in the studied alloys was explored. After aging at 450 degrees C for 60 min, the tensile strengths of Cu-2.6Cr-0.9Nb-0.15Ti (at. %) alloy were measured as follows: 468 MPa at 20 degrees C, 318 MPa at 400 degrees C, 281 MPa at 450 degrees C, 238 MPa at 500 degrees C, 187 MPa at 550 degrees C, and 140 MPa at 600 degrees C. The addition of trace Ti element effectively reduced the growth rate of Cr precipitates during hightemperature strain and contributed to the high-temperature mechanical properties. These findings are meaningful in developing high-strength Cu-Cr-Nb alloys at high temperatures.
10.1016-j.matchar.2024.114450	-1		A comparative study of the features of the microstructure of bimetallic composites of the Me-Al (Cu, Ni, Nb) type, obtained by ball milling of powder mixtures and consolidation by torsion under pressure in Bridgman anvils, was carried out. In all systems studied in this work, the formation of a nanoband structural state is observed, the elements of which are elongated predominantly along the direction parallel to the anvil plane. It has been established that in local areas characterized by the absence of the aluminum component, an SMC state without a nanolaminate structure is formed. An analysis of the features of structure formation was carried out taking into account the comparison of the characteristics of powder systems components (melting point, shear modulus and stacking-fault energy). It was shown that low shear modulus of aluminum, compared to other components, in combination with a higher homologous temperature, provides it high accommodative ability. It has been suggested that under conditions of torsion under pressure, the aluminum component, being a kind of solid lubricant, ensures slipping and flattening of stronger layers of the second component, which contributes to the formation of a nanolaminate structure in the metal-aluminum systems under consideration.
10.1016-j.matchar.2024.114463	14	strength; properties; conductivity; electrical; mechanical; cu-; grain; mpa; electrical conductivity; aging; precipitation; phase; mechanical properties; tensile; phases	The optimization of process is essential for improving the overall properties of high-strength and high- conductivity Cu alloys. This study introduces a high-temperature short-time treatment (HTSTT, 850 degrees C/5 min) into the thermo-mechanical process of a Cu-Cr-Cr alloy. Following the process of solid solution- cold rolling- HTSTT- cold rolling- aging, the tensile strength of the alloy increases from 450 MPa to 508 MPa, with the electrical conductivity increasing from 82.2 %IACS to 86.4 %IACS when compared to the conventional process of solid solution- cold rolling- aging under the same total deformation condition. The reasons for the improvement in the comprehensive properties of the alloy after introducing HTSTT are analyzed through microstructural characterization. The results indicate that the HTSTT promotes the occurrence of recrystallization, leading to grain refinement, which results in smaller grain sizes during subsequent processing. Additionally, the introduction of HTSTT changes the main texture of the alloy from (100)//X to (111)//X during the process, which is beneficial to enhancing the alloy's strength and electrical conductivity. More importantly, the HTSTT facilitates the precipitation of solute Cr atoms, leading to the formation of a significant quantity of nanoscale Cr particles, most of which are spherical with an average size of 27 nm. During the subsequent cold rolling process, these Cr particles effectively pin dislocations and promote their proliferation, leading to the precipitation of a large number of smaller Cr particles during the aging process, with an average size of 4.8 nm. These finer Cr particles are crucial for precipitation strengthening. This paper offers valuable insights into the microstructural optimization and performance enhancement of high-strength and high-conductivity Cu alloys.
10.1016-j.matchar.2024.114488	-1		The Cu-1Cr-0.1Zr alloy with different La addition (0 %, 0.07 % and 0.14 wt%) was processed using industry suitable two-step cold rolling and aging treatment to achieve superior strength and electrical conductivity. The role of La addition on the microstructure evolution and comprehensive properties of the Cu-1Cr-0.1Zr alloy is investigated during the second rolling and subsequent aging stages. During pre-aging process, the presence of La in the Cu-1Cr-0.1Zr-0.07La alloy led to formation of smaller precipitate sizes compared to La-free Cu-1Cr-0.1Zr alloy. This facilitates a stronger cut interaction between dislocations and precipitates during secondary rolling process, which promotes the redissolution of precipitates into Cu matrix and thus results in a larger decline of 44.72 % ICAS for the electrical conductivity of Cu-1Cr-0.1Zr-0.07La alloy. After post-aging treatment, precipitates are newly formed with increased number and refined size of Cr precipitates with maintaining a coherent relationship with the matrix. Besides, the addition of La promotes Cr-rich phase precipitation and dislocation accumulation. Resultantly, remarkable increase in tensile strength by 11 % with the addition of 0.07wt%La. While, the 0.14La added alloy exhibits comprehensive properties of tensile strength 600 MPa and electrical conductivity 80.08 %IACS after aging at 440 degrees C for 180 min. The increase in strength was primarily attributed to precipitation strengthening and dislocation strengthening. This work provides new kinds of Cu-1Cr-0.1Zr alloy and industrial suitable thermo-mechanical treatment for fabricating high performance cooper alloy sheets.
10.1016-j.matchar.2024.114518	-1		Electron beam powder bed fusion (EB-PBF) is one of the most promising technologies for preparing thin-walled copper alloy, because copper alloy have a high energy absorption rate for electron beam, and high preheating temperature can reduce the solidification temperature gradient and reduce the deformation of thin-walled parts. At present, there are few reports on the systematic research work on the EB-PBF of thin-walled CuCrZr alloy parts, and it's impossible to effectively supervise the production of complex thin-walled CuCrZr alloy parts. This work aims to investigate the effect of thickness on the microstructure and mechanical properties of CuCrZr alloy produced by EB-PBF. As the wall thickness decreases from 5.0 mm to 0.3 mm, the grain sizes of the XY and YZ planes decreased from 20.4 mu m and 43.1 mu m to 14.5 mu m and 21.5 mu m respectively, and the texture intensity decreased from 16.04 and 23.57 to 7.62 and 10.99. The analysis showed that Cr2O3 nanoprecipitates were precipitated in situ in the sample, and their average size decreased from 65.8 nm to 21.6 nm. Due to the reduction in grain and nanoprecipitate size, the performance of thin-walled samples is significantly enhanced, with yield strength (YS) increasing from 112 MPa to 165 MPa and conductivity increasing from 71.7 %IACS to 86.1 %IACS. Finally, the main contributions to the YS of specimens with different wall thicknesses was discussed. Precipitation strengthening and dislocation strengthening are the main strengthening mechanisms in thin-walled samples, and the gradual refinement of nano-precipitates is the main reason for the improvement of mechanical properties as the wall thickness decreases.
10.1016-j.matchar.2024.114519	-1		Cu-15Ni-8Sn (wt%) alloy has been widely used in engineering applications due to its excellent mechanical strength, wear, and corrosion resistance. However, low-temperature oxidation (LTO) poses a significant challenge, restricting its further application and longevity. In this study, the low-temperature oxidation behavior of the Cu-15Ni-8Sn alloy under different aging condition was investigated using multi-scale characterization by SEM and TEM. The characterization results reveal the oxide films of the aged sample contain tri-layers at low temperature, the outermost layer is dominated by CuO and Cu2O, the middle oxide layer contains of Cu2O, NiO, SnO2 and SnO, and the inner oxide layer is composed of NiO and SnO2. In addition, the as-quenched sample has superior oxidation resistance compared to the aged samples, and the oxidation resistance of the aged samples decreases with the increase of aging time. That is, there is a trade-off between hardness and oxidation resistance in aged Cu-15Ni-8Sn alloys. Therefore, these findings provided a way to adjust the aging parameter based on specific service conditions.
10.1016-j.matchar.2024.114575	-1		Copper-based composites with carbon nanotubes (CNTs) as the reinforcing phase possess excellent comprehensive mechanical and electrical properties and have received widespread attention in the electronics industry in recent years. However, a handful of studies concerns CNTs reinforced copper matrix composites with different wall layers. In this study, multi-walled carbon nanotubes (MWCNTs) and single-walled carbon nanotubes (SWCNTs) were selected. An improved molecular-level blending method was exploited to produce copper matrix composites reinforced by MWCNTs and SWCNTs in our study. The characterization results showed that the copper coated MWCNTs and SWCNTs were evenly distributed in the copper matrix and ensured the connection structure tightly between CNTs as heterogeneous strengthening factors and the copper matrix. Meanwhile, in the mechanical property test, the MWCNTs/Cu composite material had the highest tensile strength (262.5 MPa), which was 23.6 % higher than pure copper and 12.6 % higher than the SWCNTs/Cu composite materials. In addition, in the electrical performance test, MWCNTs/Cu and SWCNTs/Cu composites all possessed excellent electrical conductivity, 95 % IACS and 96 % IACS, respectively. The research work in this paper can be extended to the development of ultra-light copper and copper alloy electronic devices and provide a reference for future research on CNTs augmented metal matrix composites.
10.1016-j.matchar.2024.114588	14	strength; properties; conductivity; electrical; mechanical; cu-; grain; mpa; electrical conductivity; aging; precipitation; phase; mechanical properties; tensile; phases	Owing to their excellent strength and electrical conductivity, Cu-Ni-Co-P alloys present strong potential as next- generation materials for integrated circuits in electronic information systems. However, these outstanding properties are closely tied to the precise control of nanophase precipitation behavior within Cu-based alloy systems. Herein, the design of alloy composition was combined with aging treatment to regulate the nano- precipitation process. Furthermore, the effects of P content and aging treatment conditions, including temperature and duration, on the microstructure and the mechanical, and electrical properties of Cu-Ni-Co-P alloys were systematically investigated. The findings reveal that Cu-0.3Ni-0.3Co-0.16P alloys, when aged at 500 degrees C for 4 h, primarily consist of a Cu-rich matrix interspersed with numerous nanoprecipitates. These nanoprecipitates were identified as the hexagonal CoNiP phase, precipitating in Guinier-Preston (GP) zones and maintaining a coherent relationship with the Cu matrix. The as-annealed Cu-0.3Ni-0.3Co-0.16P alloys demonstrated a tensile strength of 652.9 MPa, a yield strength of 631.2 MPa, a Vickers hardness of 203.2 HV, and an electrical conductivity of 66.4 %IACS. Aberration-corrected scanning transmission electron microscopy revealed that G.P. zones suppressed the coarsening of the CoNiP phase, thereby enhancing the mechanical strength of the Cu-Ni-Co-P alloys. The strength analysis calculations suggest that fine-grain and precipitation strengthening mechanisms are the predominant factors in improving the mechanical strength of these alloys. This study provides valuable insights into the development and manufacturing of high-performance Cu-based alloys for advanced applications in the electronics industry.
10.1016-j.matchar.2024.114661	14	strength; properties; conductivity; electrical; mechanical; cu-; grain; mpa; electrical conductivity; aging; precipitation; phase; mechanical properties; tensile; phases	This study investigates the impact of hot rolling on the linear current range of the secondary electron yield (SEY) curve for activated Cu-3.0Be sheets. Analysis of the SEY curve tests revealed that the BeO layer exhibited a favorable linear dynamic range at 650 degrees C, spanning approximately 0-201 eV. SEM results indicated BeO layer rolled at 650 degrees C has a compact and smooth surface, while BeO layer rolled at 800 degrees C has a rough surface texture. The non-uniform surface morphology can hinder the emission or absorption of secondary electrons due to charge accumulation and enhanced electric field effect. BeO layer thickness was found to be 15-27 nm for samples rolled at 650 degrees C, while it was only 8-15 nm for those rolled at 800 degrees C. Furthermore, numerous dislocation lines were detected in the TEM images of samples rolled at 650 degrees C. These lines facilitate the diffusion of the Be element, leading to a thicker BeO layer following its activation. Excessively thin BeO layers can lead to collisions between excited secondary electrons and free electrons in the alloy substrate, resulting in reduced initial velocity and hindered progression to the next dynode at low voltages, which leads to a narrow linear range of current.
10.1016-j.matchar.2025.114716	14	strength; properties; conductivity; electrical; mechanical; cu-; grain; mpa; electrical conductivity; aging; precipitation; phase; mechanical properties; tensile; phases	The advancement in the collaborative regulation and control of electrical conductivity and thermal stability in pure copper is crucial for its application as a conductive material in high-power devices. This study investigates the effects of trace elements Al and Sc on the electrical conductivity and thermal stability of pure copper. Furthermore, by optical microscopy (OM), transmission electron microscopy (TEM), and electron backscatter diffraction (EBSD), we analyze the mechanisms underlying the enhanced thermal stability. The results demonstrate that the interaction between Al and Sc elements significantly enhances the thermal stability of pure copper, with the thermal stability following the order: Cu-170Al-30Sc > Cu-110Sc > Cu-10Sc > Cu. By incorporating trace amounts of Al and Sc, the softening temperature of the samples increases from 165 degrees C to 453 degrees C, while the grain size at a high temperature of 850 degrees C for 30 min decreases from 207.21 mu m to 68.13 mu m. Furthermore, the addition of these trace elements allows pure copper to retain relatively high electrical conductivity. The electrical conductivities of cold-deformed samples are measured as follows: Cu (101.87 %IACS), Cu10Sc (101.64 %IACS), Cu-170Al-30Sc (99.53 %IACS), and Cu110Sc (98.24 %IACS). The enhancement of thermal stability can be primarily attributed to the segregation of Sc at grain boundaries and the formation of the Al3Sc phase at elevated temperatures. Trace amounts of Sc do not react with the Cu matrix but instead segregate at the grain boundaries. As temperature increases, these segregated Sc elements interact with solid solution Al to form a face-centered cubic Al3Sc phase measuring approximately 18 nm at the grain boundaries. This precipitated phase exhibits a coherent relationship with the matrix, effectively suppressing atomic diffusion and thereby enhancing the thermal stability of the copper matrix. Furthermore, the conductivity of the Cu-170Al-30Sc sample was 101.05 % IACS after high-temperature annealing. This was attributed to the interaction between trace amounts of Al and Sc at high temperatures, which modified the existence form of the trace elements and mitigated the impact of element solid solution on the conductivity of the copper matrix.
10.1016-j.matchar.2025.114729	-1		Cast Al-containing cupronickel alloys are the promising materials for marine applications. However, due to addition of multiple alloying elements, the microstructural development and transformation products become rather complicated that must be fully understood to optimize the mechanical properties. In this contribution, the microstructure characteristics of a cast Cu-17Ni-3Al-based alloy are systematically investigated using a combination of experiments and theoretical calculations. Two novel hierarchical precipitations at both the grain boundaries and grain interiors are revealed. The intergranular precipitates (in micron and submicron scales) consist of G phase, Cr-rich phase and B2 phase, where the Cr-rich phase and G phase are mainly eutectic products that can serve as a nucleation site for the B2 phase at low temperature. By contrast, the intragranular precipitates (in nano-scale) are mainly comprised of γ′-ordered phase with types of primary and secondary ones. For the first time the splitting of γ′ phase is observed in the Cu alloys, where the splitting product is FeCrNi-rich phase with a disordered FCC structure and fully coherent interface with the γ′ phase. This may support the splitting mechanism of thermodynamically driven rather than the pure elastic driven as remaining disputable in Ni-based alloys. First-principles calculations are performed to address the alloying substitution effect on the nucleation of γ′ phase in terms of the interfacial energy. The preferred occupation site by Cu at the Cu/Ni3Al interface is revealed. The present study may shed new light on the alloy design of high-performance cupronickel alloys by utilizing hierarchical precipitation strategy.
10.1016-j.matchar.2025.114747	-1		The Cu-Al-Fe shape memory alloys were fabricated by laser powder bed fusion (LPBF). The investigation focused on examining the influence of different Al content on the phase transition, microstructure, mechanical properties, and shape memory properties in the as-deposited state (LPBF sample) and quenched state (LPBF-RT sample). The findings of this research indicated that the alloys fabricated by LPBF exhibit significantly finer grains in all compositions, with grain sizes of 2-5 mu m, which are smaller than the 10-15 mu m of the quenched state samples. The austenite start temperature (As) was observed to be approximately 300 degrees C and increased to about 350 degrees C after quenching. Significantly, an increase in the Al content resulted in an increase in the phase transition hysteresis. The 13Al exhibited the most significant proportion of martensite by contrast, concomitant with the most pronounced peaks in the phase transition. Furthermore, an analysis was conducted on the compressive strength, tensile strength, and micro-hardness of the alloys. As the Al content increased, the plasticity and toughness of the alloy exhibited a gradual improvement. The compressive strength of various samples was approximately 1200 MPa, while the tensile strength was approximately 400 MPa. After quenching, the compressive and tensile strengths were further increased, albeit with a decrease in hardness. Shape memory tests determined the shape memory properties of the alloys after quenching. Through the bending deformation and shape memory experiment, 13Al had the highest shape recovery when the sample was bent at 40 degrees, about 80.3 %. In comparison, 13Al has superior performance in experimental processes.
10.1016-j.matchar.2025.114756	-1		In this study, Copper-based (Cu) metal matrix composites were successfully fabricated by using a novel microwave hybrid heating (MHH) technique. The copper powder, reinforced with varying proportions of tungsten (5-15 %W) and molybdenum (5-15 %Mo) by weight fraction, was processed in a conventional 900 W maximum power and fixed 2.45 GHz domestic microwave oven. The composite samples were then evaluated for their mechanical and metallurgical properties. The average raw powder particle size used in the casting process had an approximately 30 mu m. The various characterizations tools/techniques were performed like, Scanning Electron Microscopy (SEM), X-ray diffraction (XRD), and Vicker's microhardness testing on the developed composite casts. The microstructural analysis revealed a uniform cellular-like solidification pattern with finely recrystallized grains, representing uniform like reinforcement distribution. X-ray diffraction (XRD) analysis confirmed the presence of intermetallic combinations and typical oxide phases such as Cu64O and CuWO4 in Cu-W, Cu6Mo5O18, and MoO2 within the composite matrix. The composite castings exhibited a maximum porosity level of 0.61 +/- 0.41 %. The relative density was found 98.71 % increase in Cu + 15 %W within the casting. The Vickers's microhardness testing revealed that the average microhardness of the Cu + 15 %W composites was 147.23 +/- 7.36 HV0.3, demonstrating a significant improvement in hardness, specifically 2.16 times higher than the microhardness of microwave-processed pure Cu and 1.47 times better than 15 %Mo reinforcement.
10.1016-j.matchar.2025.114780	-1		The effects of additives, Co2+ ions, and plating temperature on the mechanical properties and microstructures of nanotwinned copper (NT-Cu) foils are investigated. Results show that these factors increase overpotential and reduce grain size/twin spacing. As the content of additives increases, the conductivity decreases, and the strength-ductility trade-off is found. However, we find that Co2+ ions enhance the tensile strength without sacrificing ductility and conductivity. Utilizing the three strengthening factors, we are able to electroplate highperformance NT-Cu foils with excellent thermal stability. The ultimate tensile strength and yield strength can achieve 866 MPa and 640 MPa, respectively. Besides, the elongation and electrical conductivity are well maintained at 3.3 % and 82 % international annealed Cu standard (IACS), respectively. Such thin NT-Cu foils can be simply produced by direct current (DC), which is compatible with the semiconductor processes. The study offers an effective method to enhance the mechanical properties of the NT-Cu foils with excellent electrical conductivity and thus widen their applications.
10.1016-j.matchar.2025.114784	-1		Cu-Cr-Zr alloy is a candidate material for the heat sink components of divertor in future fusion device, which is required for high strength and thermal stability simultaneously. In this study, the Cu-0.76Cr-0.23Zr (wt%) alloy is prepared through room temperature rolling-aging-liquid nitrogen rolling (LNR) to form fine precipitates and twin/matrix coexisting structures. Besides, room temperature rolling-aging (RTR) method is also adopted as the contrastive route. The results indicates that the twin boundary with an average width of 53 nm is achieved in LNR. The yield strength of LNR Cu-Cr-Zr are 638, 544, 414 and 213 MPa at 273, 473, 673 and 873 K, which are higher than those of RTR sample by 180, 139, 80 and 37 MPa, respectively. The higher strength is attributed to the high dislocation density and unique twin boundary. Then both kinds of samples are subjected to isothermal annealing at 500, 600, 700, 800 and 900 K for 1 h to study the softening behavior. The LNR sample always shows higher hardness than RTR sample. The high thermal stability is related to the newly formed precipitates (on twin boundaries), Sigma 9 boundaries and stair-rod dislocations during the annealing process. Besides, studies of static recrystallization behavior suggest that the low mobility of partial dislocations and the hindrance of twin boundaries to dislocation motion led to a high recrystallization activation energy of 111 kJ/mol for newly developed Cu-Cr-Zr alloy. These findings underline the important interplay among precipitates, twin structures, and mechanical properties, and offer a promising design strategy for developing Cu-Cr-Zr alloy suitable for high- temperature applications.
10.1016-j.matchar.2025.114795	-1		The Cu-Al bronze alloy CuAl10Ni5Fe5 has been widely used in maritime components, such as large ship propellers, for many decades because of its excellent corrosion resistance and mechanical properties. The alloy is mainly manufactured by casting. In the present work, its micro- and nanostructural development during cooling from solution treatments is investigated. The cooling rates were varied over four orders of magnitude. The precipitation and transformation kinetics are examined in situ by differential scanning calorimetry. The differential scanning calorimetry cooling curves show a complex superposition of multiple reactions. The reactions cover a temperature range of about 800 K. To assign some distinct reactions to certain temperature ranges, a defined step quenching method has been applied. Extensive investigations on the resulting microstructure were performed by optical microscopy, scanning electron microscopy, and transmission electron microscopy. It is found that numerous structural features evolve during cooling (depending on the cooling rate), including formation of alpha-Cu grains, precipitation of several types of secondary x-precipitates. The microstructural development of these xI, xII, and xIII precipitates is more complex, as these particles are found to contain multiple types of tertiary phase particles. Tthe development of the microstructure is correlated with the resulting mechanical properties, in a way that the hardness is tested after cooling at different rates.
10.1016-j.matchar.2025.114833	-1		Laser powder bed fusion (LPBF) technology has significantly grown to fabricate copper-based material with high degree of control over geometry. The addition of ceramic particles in LPBF of Cu has recently become a promising method for increasing processability and strength while maintaining high conductivity. The work herein produces a high strength and high conductivity Cu composite reinforced by 2 wt% TiB2 reinforcing particles using LPBF. Adding TiB2 reinforcing particles could eliminate unmelted powder and cracks, achieving a high relative density of 99 %. Unlike the LPBF of pure Cu with an equiaxed-columnar bimodal grain structure, the TiB2/Cu composite presents a fully coarse columnar grain. TiB2 particles are uniformly distributed within the Cu matrix and provide strengthening contribution of 111 MPa. Compared to the LPBF-fabricated pure Cu, the TiB2/Cu composite exhibits a superior combination of strength (similar to 298 MPa) and electrical conductivity (similar to 78 % IACS).
10.1016-j.matchar.2025.114883	-1		Nanocrystalline Cu has the merit of high strength but usually suffer from poor electrical conductivity and rapid grain coarsening, limiting its practical application. Here, we demonstrate that this challenge can be overcome by architecting a unique nanolaminated grain structure (NGS) with an ultra-thin lamellae boundary spacing of similar to 55 nm, featuring pronounced Ag atoms segregation at high angle lamellae boundaries and very few defects inside the lamellae interiors, in a Cu-5wt%Ag alloy. Benefiting from the synergistic contributions from the NGS, pronounced Ag atoms segregation at lamellae boundaries and continuous electron transport channels as well as a low electron scattering within the lamellae interiors, the resultant NGSed Cu-5wt%Ag alloy achieves an ultrahigh tensile yield strength (YS) of 895 MPa, together with an excellent electrical conductivity of similar to 83 % IACS (International Annealed Copper Standard) and a good thermal stability of 400 degrees C (similar to 0.4 Tm). The structure design strategy reported here, via nanolamellar grain structure combined with solute atoms decoration at lamellae boundaries, represents a promising approach that may be widely applicable to develop high strength, conductivity, and thermally stable nanostructured Cu-based materials for future structural and functional applications.
10.1016-j.matchar.2025.114925	-1		Traditional metal alloying usually offers enhanced strength but generally reduces the conductivity. In this study, we prove that incorporating Fe ions can break the strength conductivity trade-off in electroplated nanotwinned copper (NT-Cu) foils. An enhancement of 13 %, from 758.6 MPa to 862.5 MPa was achieved. The microstructure, twin spacing, grain size, and orientation of the foils were analyzed using focused ion beam, transmission electron microscope, and electron backscattered diffraction. Additionally, linear sweep voltammetry analysis was performed to investigate the inhibitory effects of Fe ions. Results show that the strength-conductivity synergy is due to the grain/twin spacing refinement effect of Fe ions in the electrolyte. The presence of Fe ions suppresses the growth of Cu foils and increases the reduction overpotential leading to higher nucleus density (more nucleation sites during the initial stages of electrodeposition). Fe ions further refine the equiaxed grain structure producing ultrafine grains while preserving nanotwins within the Cu grains. The electroplated NT-Cu(Fe) foils also demonstrated good thermal stability and high electrical conductivity (85.4 %, international annealed Cu standard-IACS). This technique could widen new avenues for the development of the next generation of electrical interconnects.
10.1016-j.matchar.2025.114928	7	irradiation; shear; grain; ta; deformation; size; radiation; voids; nanocrystalline; simulations; similar; void; temperature; irradiated; boundaries	Understanding the deformation mechanisms behind microstructural evolution during shear loading has been a long-standing area of interest. However, establishing a connection between microstructure, mechanical properties, and the extent of shear deformation is challenging and requires refined experimental approaches. Microshear testing offers a controlled method to introduce shear into small volumes of material, allowing for detailed site-specific microstructural characterization. In this work, we investigated the shear deformation behavior and properties of copper (Cu) matrix and at copper-niobium (Cu-Nb) interfaces using micro-shear testing. The yielding under shear loading is dependent on the orientation of the interfaces. Intuitively, when the interface is along the shear direction, the flow stresses are lower compared to when it is across. Transmission electron microscopy examination shows stacking faults and high dislocation density dominating the deformation on the Cu side while limited dislocation activity in the neighboring Nb crystal. Moreover, an amorphous layer was observed at the Cu-Nb interface which likely formed after shear deformation. In summary, our study provides an understanding of the shear deformation behavior of phase-interfaces in an immiscible system at a micro-scale. The focus of the paper is demonstrating the applicability of the S-shaped pillar geometry for local shear measurements and deformation of specifically oriented interface boundaries.
10.1016-j.matchar.2025.114947	-1		Mo-Cu composites are extensively applied in various aspects due to their excellent properties. The poor interfacial bonding between the two phases leads to inferior mechanical properties and other drawbacks. In this work, the Mo-30wt%Cu (MC30) composites were prepared from the ultrafine Mo powder and Cu powder through powder sintering, rolling, and heat treatment processes. It was found that forming interfacial diffusion layers during the deformation process significantly improved the strength and plastic deformation ability of Mo-Cu alloys while maintaining excellent electrical properties. The microstructure evolutions of MC30 composites under different conditions were investigated through characterizations using EBSD and TEM technologies. In addition, the interfacial diffusion layer with a thickness of approximately 13 nm was formed after thermo-mechanical deformation, which possessed a high interfacial coordinated deformation capability and greatly improved the plastic deformation capability (17.7 %) while ensuring a high strength (624 MPa), as well as a good electrical conductivity (48.6 % IACS). The interdiffusion layer caused the fracture mechanism of the MC30 alloy to shift from transgranular fracture to the mixed mode of ductile and brittle fractures.
10.1016-j.matchar.2025.114957	-1		Thermomechanical treatment plays a crucial role in microstructure regulation and properties optimization of precipitation-hardening Cu alloys. In this study, the influence of pre-aging on the microstructure and properties evolution of cold-rolled Cu-1.2Ni-0.9Co-0.5Si alloy during final aging has been systematically investigated. The results demonstrated that pre-aging induced an increase in dislocation density and facilitated the precipitation of fine precipitates, thereby resulting in a simultaneous enhancement of both strength and electrical conductivity. The Cu-1.2Ni-0.9Co-0.5Si alloy treated by pre-aging at 500 degrees C for 1 h exhibits a tensile strength of 791.5 MPa and an electrical conductivity of 45.3 % IACS, which are both superior to the counterparts of the alloys without pre-aging treatment (755.5 MPa and 42.2 % IACS). However, as aging proceeded, the pre-aging treated alloy exhibited an accelerated decline in dislocation density due to enhanced recrystallization and a more pronounced tendency for precipitation growth compared to the untreated alloy. Consequently, the pre-aging treated alloy showed a more conspicuous softening phenomenon and resultant lower strength level during over-aging period than the untreated one.
10.1016-j.matchar.2025.114959	-1		The microstructures and mechanical properties of gradient Cu-9.0 at%Ge alloy produced by surface mechanical attrition treatment (SMAT) with different durations at the liquid nitrogen temperature have been investigated. In the process of SMAT, the gradient distribution of defects, including dislocations, twins, and stacking faults was formed. The SMATed alloy showed more than twice the yield strength, while the uniform elongation remained as much as similar to 0.65, comparable to that in the untreated samples, suggesting excellent strength-ductility synergy. Multiple strengthening mechanisms promoted strengthening and hardening, including dislocation pile-up, deformation twinning, and stacking faults. The accommodation deformation between the surface hard and central soft layers induced strain delocalization. The strength-ductility synergy of the alloy is attributed to the high strain hardening rate caused by hetero-deformation-induced (HDI) hardening, strain delocalization, and synergistic strengthening. The study provides new insights and guidelines for the future design of gradient materials.
10.1016-j.matchar.2025.114973	14	strength; properties; conductivity; electrical; mechanical; cu-; grain; mpa; electrical conductivity; aging; precipitation; phase; mechanical properties; tensile; phases	This study conducted a detailed analysis of the microstructure evolution and mechanical properties of a series of CuxCoCrNiAl high-entropy alloys (HEAs) to assess the influence of Cu content on HEAs. The findings indicated that with increasing Cu content, the alloy's phase structure changed from FCC1 + FCC2 (AlCu) + BCC to FCC phase. As the Cu content rose from 20 % to 80 %, the hardness of the alloy decreased progressively from 515 HV to 135 HV, and the ultimate tensile strength reduced from 1335 MPa to 524 MPa. The fracture mechanism shifted from a mixed brittle-ductile fracture to a ductile fracture. Consequently, the Cu4CoCrNiAl HEA (CA50) demonstrated superior overall mechanical properties, with hardness, yield strength, ultimate tensile strength, and elongation measured at 321 HV, 556 MPa, 846 MPa, and 16.4 %, respectively. This research is significant for the advancement of engineering and structural materials with outstanding mechanical properties.
10.1016-j.matchar.2025.115105	8	hot; deformation; strain; strain rate; dynamic; hot deformation; recrystallization; dynamic recrystallization; flow; rate; flow stress; compression; constitutive; degrees; stress	Generally, adiabatic shear bands (ASBs) are formed under the conditions of dynamic loading and high strain rate deformation. Recently, we have observed the formation of the ASBs in ultra-coarse grained copper (Cu) alloys under quasi-static tensile loading. Our experimental results extend the formation mechanism and conditions of the ASBs. The results show that the addition of trace La and Nd elements in pure copper can promote the randomization and diversification of deformation texture, and inhibit the dynamic recovery process. The deformation mechanism of the as-casted rare-earth modified Cu alloy mainly includes grain boundary coordination deformation, dislocation slip and adiabatic shear deformation. The strengthening mechanism of the alloy mainly involves dispersion strengthening, grain refinement strengthening and strain hardening. The ASBs are formed in the pure Cu and Cu alloys during quasi-static tensile deformation, which is mainly related to the dynamic recrystallization process and the low strain rate sensitivity of the ultra-coarse grained Cu alloys.
10.1016-j.matchar.2025.115110	-1		The dual phase (alpha/beta) Cu-Zn alloys play a major role in the electronics industry due to their excellent mechanical properties and high electrical conductivity. The effects of the initial phase (alpha and beta phase) on the microstructure evolution, dislocation density, and mechanical properties of the dual phase (alpha/beta) Cu-Zn alloy during cold-rolling were researched in this paper. The specimens with two different heat treatment states (600 degrees C/1 h and 700 degrees C/1 h) were selected as the initial samples, and in the subsequent cold rolling with the thickness reduction of 31 %, 50 %, and 75 % respectively. The experimental results show that the content of the beta phase significantly increases after heat treatment, and it precipitates from the grain boundaries of the alpha phase. A minute quantity of tiny beta phase is present within the alpha phase at the treatment temperature of 600 degrees C. However, the tiny beta phase disappears, and the proportion of the beta phase increases from 22.2 % to 36.4 % at higher heat treatment temperatures of 700 degrees C. On this basis, after the rolling treatment, the grains of the alpha/beta Cu-Zn alloy are significantly elongated, changing from equiaxed grains to fibrous grains. An improvement in yield strength from about 108.2 MPa to 473.6 MPa similar to 626.0 MPa. Meanwhile, the elongation of the material decreases from 42.1 % to 3.6 % and the fracture changes from ductile fracture to a mixed characteristic of ductile and brittle fracture. When the thickness reduction is 75 %, obvious grain rotation, substructure, and twin boundaries appear in the beta phase grains, while the alpha phase shows a significant < 101 > preferred orientation. In addition, as the thickness reduction increases, the difference in mechanical properties and elongation after fracture between the alpha/beta Cu-Zn alloy heat-treated at 600 degrees C and 700 degrees C gradually decreases. At this time, dislocation strengthening becomes the main strengthening mechanism, and the effect of the beta phase on the mechanical properties of the material gradually decreases. The research results can provide guidance in the micro-forming for the alpha/beta Cu-Zn alloys
10.1016-j.matchar.2025.115184	14	strength; properties; conductivity; electrical; mechanical; cu-; grain; mpa; electrical conductivity; aging; precipitation; phase; mechanical properties; tensile; phases	Through the adjustment of the multi-stage rolling process to induce deformation twinning and alter the precipitation behavior of Sc-rich phases, we developed an advanced Cu-Cr-Zr-Sc alloy with excellent tensile strength (631.33 +/- 10.9 MPa), yield strength (597.14 +/- 9.26 MPa), hardness (219.06 +/- 3.94 HV), electrical conductivity (63.3 +/- 0.16 % IACS), and wear resistance, comparable to alloys produced by severe plastic deformation under optimal multi-stage rolling conditions (60 % CR1 + 450 degrees C x 2 h + 50 % CR2 + 200 degrees C x 1 h). The uniform distribution of Cu-4(Sc, Zr) at both the micron scale (similar to 1.5 mu m) and nanoscale was a key factor in achieving high hardness while maintaining high strength . Meanwhile, under the optimal rolling conditions, the alloy remained high electrical conductivity due to the near-equal rolling reductions in two stages, which induced the formation of more deformation twins. During the friction process, the higher matrix strength facilitated the transfer of oxides to the matrix, effectively reducing the friction coefficient. Compared to the non-doped Sc alloy (similar to 61.68 mu m), the wear track depth was reduced by nearly half (similar to 34.92 mu m). Furthermore, we observed short rod-like stacking faults within the matrix, which were caused by Shockley partial dislocations. Finally, we found that some of the Sc exists in the form of atomic clusters within the Cu alloy indicating that, in addition to grain boundary strengthening, dislocation strengthening, and precipitation strengthening, cluster strengthening is also a key factor in improving the alloy's strength and maintaining high ductility.
10.1016-j.matchar.2025.115223	14	strength; properties; conductivity; electrical; mechanical; cu-; grain; mpa; electrical conductivity; aging; precipitation; phase; mechanical properties; tensile; phases	This study investigates texture, elasticity, and mechanical properties changes in bulk Cu-37Zn alloy samples after high-energy shock compression (HESC) and ultrasonic impact treatment (UIT) at ambient (air-UIT) and cryogenic (cryo-UIT) temperatures using ultrasonic texture analysis, which enables non-destructive assessment of these properties, including geometrically inaccessible directions. HESC induces a copper-to-brass texture transition, typical for such alloys under shock compression. Remarkably, air-UIT reverses this transition, causing a novel brass-to-copper transformation, whereas cryo-UIT preserves the brass-type texture. Since face center cubic (FCC) alloys typically evolve from copper to brass texture, the latter represents the final stage of texture development. The alternating component of UIT plays a crucial role in the inverse texture transition by mobilizing dislocations and breaking their anchoring points, reverting texture to the copper type. In contrast, cryo-UIT suppresses defect mobility, promoting twinning over slip and maintaining the brass-type texture. Transmission electron microscopy observations confirm the dominating involvement of dislocation activity and twinning for the air-UIT and cryo-UIT processed samples, respectively. HESC significantly increases Young's modulus anisotropy by reorienting (111) crystallographic directions along the normal and transverse sample axes. UIT, at both temperatures, reduces elastic anisotropy nearly twofold due to grain refinement and increased grain boundary fraction. These findings reveal the first observed brass-to-copper texture transition after air-UIT. Optimizing HESC and UIT parameters enables precise control over texture and elastic properties in Cu-37Zn alloys.
10.1016-j.matchar.2025.115258	-1		The excellent strength and creep resistance of superalloys derive principally from the coherent precipitation of gamma' phase. The precise determination of precipitate volume fraction remains a critical challenge in quantifying structure-property correlations for precipitation-strengthened superalloys. However, conventional characterization methods including stereological analysis and X-ray diffraction exhibit inherent limitations in precisely determining precipitate volume fraction. To solve this problem, we propose a microstructure model for alloys with uniformly distributed and equi-sized precipitates, which defines a unit centered on the precipitate and surrounded by portions of matrix and arranges in a close-packed structure in space. The microstructure unit represents the smallest average microstructure of the alloy, thus the precipitate volume fraction within the unit equates that in the overall alloy, which can be calculated through precipitate diameter and inter-precipitate spacing. Coherent gamma' phase was introduced into copper alloys to design a series of Cu-Ni3Al alloys and the volume fraction of gamma' phase was calculated based on the microstructural unit model. Inter-precipitate spacing were measured through atomic force microscopy (AFM) to mitigate the projection-induced spacing errors inherent in two-dimensional imaging techniques such as scanning electron microscopy (SEM). The results demonstrate errors of less than 3.3 %, significantly lower than the 8.8-21.4 % variability range observed in traditional stereological method. This approach enhances efficiency and accuracy by replacing two-dimensional area fraction analysis with combined spacing and diameter measurements, providing an advanced methodology for quantifying precipitate volume fraction in superalloys.
10.1016-j.matchar.2025.115293	7	irradiation; shear; grain; ta; deformation; size; radiation; voids; nanocrystalline; simulations; similar; void; temperature; irradiated; boundaries	Understanding flaw tolerance in composites is critical for both the design and the application of reliable structural materials. Through uniaxial tension experiments, we explored notch-related plastic deformation mechanisms in both Cu-alumina and Cu-Ag-Zr composites via real-time strain mapping. Experiments demonstrated that, in samples under tensile loading with notch pairs from both materials, highly strained regions first emerged from notch tips and then developed into strain-concentration bands. Under further loading, each of these bands changed in shape from straight to elliptical as it formed a bridge across to its opposite notch tip. When any sample came under tension, its notch tip radius increased, and its strain-concentration bands gradually moved toward its notch segment center. High plastic strain became localized at the notch tips, of course, but also within the strain-concentration bands. Notch-strengthening, on the other hand, appeared mainly within the strain-concentration bands. The two composites showed different ductility within these bands. Alumina-particlestrengthened Cu had low elongation that eventually resulted in an abrupt fracture somewhere within these bands. By contrast, Ag-fiber-strengthened Cu-Ag-Zr nanocomposites had high elongation in strain-concentration bands, accompanied by clear notch blunting. In other words, Ag-fiber-strengthened Cu had higher flaw tolerance than alumina-particle-strengthened Cu, a difference we attributed to the differences between malleable fibers and hard particles.
10.1016-j.matchar.2025.115308	-1		To further enhance the magneto-electric and mechanical properties of Cu-Fe alloys, the Cu-5wt%Fe alloy was fabricated by the combination of powder metallurgy and thermomechanical processing in this study. The phase constituents, elemental distribution, and microstructural evolution of the Cu-5wt%Fe alloy were characterized by X-ray diffractometer (XRD), scanning electron microscope (SEM), electron backscatter diffraction (EBSD), and transmission electron microscope (TEM), and the electrical conductivity, magnetic and mechanical properties of the Cu-5wt%Fe alloy were tested as well. The results reveal that fine Fe phases are uniformly distributed within the Cu matrix. The apparent discrepancy in yield strength between the Cu matrix and the Fe phase leads to nonuniform deformation of the Cu matrix and Fe phase during thermomechanical processing. Moreover, thermomechanical processing promotes the precipitation of the alpha-Fe phase from the Cu matrix, which enhances the electrical conductivity. Furthermore, the increased volume fraction of the alpha-Fe precipitate phase and the reduction in dislocation density enhance both the permeability and saturation magnetization of the Cu-5wt%Fe alloy. The high yield strength of Cu-5wt%Fe alloy can be attributed to the combined effect of grain boundary strengthening, dislocation strengthening, and precipitation strengthening. This study provides valuable insights into the development and processing of Cu-Fe alloys for electromagnetic shielding applications.
10.1016-j.matchar.2025.115317	-1		Boron nitride nanosheets (BNNS) are considered to be promising reinforcements of copper matrix self-lubricating composites (CMSCs), whereas the inefficient interfacial adhesion impedes breakthrough in wear resistance. Herein, BNNS reinforced copper matrix composites (BNNS/Cu) were prepared via matrix-alloying (adding 1.0 wt% Ti) strategy combined with powder metallurgy. The in-situ formed TiN transition layer through optimized heat treatment process promoted the strong BNNS-Cu interface bonding and effectively alleviated stress concentration. During the sliding process, BNNS&TiN-enriched lubrication film formed on the wear surface exhibited significant lubricating properties. An amorphous oxide protective layer was formed on the wear surface under the action of frictional heat, inhibiting more severe oxidative wear. Additionally, stacking faults (SFs) and deformation twins induced by wear shear strain were important in coordinating the plastic deformation. The enhanced interface configuration demonstrated superior wear resistance, specifically, the coefficient of friction (COF) was reduced to 0.26 (approx. 60 % lower than pure Cu), and the wear rate was 5.07 x 10-4 mm3 center dot N- 1 center dot m- 1 (only a fifth of pure Cu). The findings provided a strategy for improving the wear resistance of 2D reinforcement reinforced CMSCs through tailoring the interfacial structure between reinforcements and Cu matrix.
10.1016-j.matchar.2025.115542	-1		The study explored the impact of deposition parameters, particularly the amount of ZrO2 particles and current density, on structure, microstructure and compositional attributes of Cu-Ni-W/ZrO2 metal matrix nanocomposite coatings for their formulation as advanced materials. Nanocomposite coatings composed of Cu-Ni-W alloy matrix, reinforced with 8 mol% yttria-stabilized ZrO2 ceramic particles, were successfully synthesized using the direct current electrodeposition method. The selected area electron diffraction patterns obtained from high-resolution transmission electron microscopy analysis have confirmed the presence of multiple crystallographic phases of ZrO2 within the composite matrix. The diffraction spots were assigned to the (101), (002), (222), (331), and (114) crystallographic planes of the tetragonal phase, whereas the monoclinic phase was identified by the (-202) and (031) diffraction planes. Additionally, the (420) diffraction plane was associated with the cubic phase of ZrO2. The X-ray diffraction analysis confirmed the presence of characteristic diffraction peaks at 2 theta values of 43.7 degrees, 50.9 degrees, and 74.2 degrees, which were attributed to the (111), (200), and (220) planes of the face-centred cubic structure of Cu-Ni-W. The field emission scanning electron microscopy images indicated that coatings consist of a highly refined, compact, and crack-free morphology with thickness of similar to 340 to 420 nm. The findings from Energy Dispersive Spectroscopy confirmed that coatings were rich in copper, containing Cu 69-90 wt%, Ni 2-19 wt%, and W 1-5 wt%. Additionally, the concentration of incorporated ZrO2 ceramic particles was found to vary between 1 and 9 wt% in the composite coatings. The Cu-Ni-W/ZrO2 MMNC coatings demonstrated improved mechanical characteristics, as evidenced by a reduction in indentation depth from 76 to 51 nm and an increase in hardness to 5.5 GPa with the rise in ZrO2 concentration from 5 to 30 g/L in the electrolyte. The maximum elastic modulus of 110 GPa, was attributed to phase multiplicity, grain refinement, and the rigid reinforcement of the ZrO2 nanoparticles.
10.1016-j.matchar.2025.115552	-1		Oxide dispersion strengthened (ODS) Cu alloy is a kind of structural material with high thermal conductivity and high stability. It is promising to maintain mechanical integrity under thermal conductivity and high temperature conditions. These excellent properties are directly or indirectly attributed to the ultra-high number density of nano oxide particles, which act as a strong barrier for grain growth, dislocation slip and grain boundaries (GBs) slip. In this study, Cu-Cr-Y-Al-Ti-Si and ODS Cu-Cr-Y-Al-Ti-Si alloys were prepared by combining mechanical alloying with spark plasma sintering (SPS) technology. The influence of Cu2O on the microstructure, mechanical properties, and thermal stability of the Cu-Cr-Y-Al-Ti-Si alloy were investigated. Both alloys exhibited a heterogeneous mixture of coarse and fine grain structures. However, the addition of Cu2O led to grain refinement and the precipitation of a high density of uniformly distributed, nano-sized oxide particles throughout the copper matrix. Compared to the Cu-Cr-Y-Al-Ti-Si alloy, the ultimate tensile strength of the ODS Cu-Cr-Y-Al-Ti-Si alloy escalated from 409 MPa to 482 MPa, while the elongation slightly decreased from 17.2 % to 15.2 %. The ODS Cu-Cr-Y-Al-Ti-Si alloy also demonstrates a room temperature thermal conductivity equivalent to 62.8 % of pure copper, and exhibits ultra-high microstructural stability after annealing at 600 degrees C for 100 h . The outstanding strength, ductility and high-temperature stability are primarily owing to the coherent nano-sized Y-X-O (X = Al, Ti, Si) particles dispersed in the ultra-fine grain copper matrix. These findings indicate that by integrating component design and process optimization, it is possible to effectively and efficiently produce ODS Cu-Cr-Y-Al-Ti-Si alloy, which holds promising application prospects in structural materials for nuclear fusion reactors.
10.1016-j.matchar.2025.115605	14	strength; properties; conductivity; electrical; mechanical; cu-; grain; mpa; electrical conductivity; aging; precipitation; phase; mechanical properties; tensile; phases	This study examined the impact of defocus distance (D) and volumetric energy density (Ev) on the melt pool morphology, surface properties, and microstructure of a pre-alloyed 70/30 copper-nickel fabricated using laser powder bed fusion (LPBF). Samples were created with defocus distances ranging from-20 mm to 20 mm and energy densities between 125.0 and 381.0 J/mm3. Analysis methods included optical microscopy, surface topography, and electron backscatter diffraction. A defocus distance of-10 mm combined with moderate energy density (125.0-222.2 J/mm3) yielded deep V-shaped melt pools, low surface roughness (Ra = 23.6 mu m), well-aligned crystallographic textures with a Multiple of Uniform Density (MUD) of 6.59. Positive defocus (D = 20 mm) with high energy density produced shallow, disk-like melt pools with acceptable roughness, favoring (001) crystallographic texture. Although deep V-shaped melt pools enable enhanced penetration, they are more susceptible to defects caused by keyhole formation. Conversely, shallow disk-shaped conduction mode melt pools offer better stability and fewer surface irregularities, but they may suffer from insufficient penetration and other drawbacks. These findings highlight the potential of using defocus parameter as a key design parameter to optimize melt pool characteristics for specific material and process requirements in LPBF.
10.1016-j.matchar.2025.115663	15	aging; strength; conductivity; electrical conductivity; electrical; mpa; treatment; strengthening; degrees; cu-; cold; precipitation; tensile strength; tensile; iacs	The trade-off between strength and electrical conductivity poses a challenge for the use of copper-titanium (CuTi) alloys as current-carrying components. In the study, different rolling routes (different hot rolling temperature + room rolling (RR)/ cryogenic rolling (CR)) were designed, and the effects of rolling routes on alpha-Cu, Ti-rich phase and (3'-Cu4Ti precipitated phase of Cu-3 wt% Ti alloy were systematically studied, further the mechanism between microstructure and mechanical and electrical conductivity properties was revealed by quantitatively calculating the strengthening mechanism and the electrical conduction mechanism. Experimental results show that hot rolling temperature significantly affects the dynamic recrystallization volume fraction, alpha-Cu grain size, and the content and size of the Ti-rich phase. Compared with RR, CR leads to the generation of large number of nanoscale deformation twins through inhibiting dislocation slip and activating twinning deformation, and the thickness of the twin lamellae in CR sheets is only about half of RR sheets. A uniform dispersion of (3'-Cu4Ti precipitates is further promoted by the high-density nanoscale deformation twins, ultimately driving synergistic property enhancement of CR sheets. Compared with RR sheets, the tensile strength, microhardness, fracture elongation, and electrical conductivity of CR sheets are simultaneously improved by 11.27 %, 8.12 %, 18.2 %, and 7.35 %, respectively. The synergistic improvements of tensile strength, microhardness, fracture elongation, and electrical conductivity are directly related to the precipitation strengthening and the reduction of electron scattering due to the dispersed distribution of (3'-Cu4Ti phases.
10.1016-j.matchemphys.2006.08.011	-1		The Ti-added (0%, 5%, and 10%) MgB2/Cu superconducting wires were prepared by the powder-in-tube (PIT) method. Mechanical properties of the samples were then characterized by using a dynamic ultra-microindentation experimental technique. We observed that the sink-in effect is significant in our samples. So, the loading-unloading (P-h) curves were analyzed by the displacement approach to indentation. It was found that hardness (H) and the effective elastic modulus (E) values increased with added Ti. In addition, these values showed peak load dependence (i.e. indentation size effect (ISE)).
10.1016-j.matchemphys.2007.01.003	-1		With an aim to understand the great reduction in the X-ray diffraction (XRD) intensities of high-entropy alloys, a series of Cu-Ni-Al-Co-Cr-Fc-Si alloys with systematic addition of principal elements from pure element to seven elements was investigated for quantitative analysis of XRD intensities. The variation of XRD peak intensities of the alloy system is similar to that caused by thermal effect, but the intensities further drop beyond the thermal effect with increasing number of incorporated principal elements. An intrinsic lattice distortion effect caused by the addition of multi-principal elements with different atomic sizes is expected for the anomalous decrease in XRD intensities. The mathematical factor of this distortion effect for the modification of XRD structure factor is formulated analogue to that of thermal effect.
10.1016-j.matchemphys.2008.03.005	-1		The magnetic properties of Cu-Ni, Cu-Fe and Cu-Co binary alloys prepared by ball milling and subsequent isothermal annealing have been investigated systematically. A detailed microstructural characterization by X-ray diffraction (XRD) and high-resolution transmission electron microscopic (HRTEM) analysis shows that single phase Cu-Ni solid solution formed by isothermal annealing of ball-milled Cu-Ni powder blend deteriorates the magnetic properties. In contrast, isothermal annealing of Cu-Fe and Cu-Co powder blends resulted into significant improvement of magnetic properties due to precipitation of Fe and Co from the respective supersaturated solid solution. Dispersion of Co nanoparticle in Cu matrix yielded the most attractive magnetic properties.
10.1016-j.matchemphys.2008.06.039	2	corrosion; surface; film; electrochemical; films; spectroscopy; layer; current; solution; potential; resistance; composition; x-ray; ions; showed	The corrosion inhibition of Al and its two copper alloys are the subject of tremendous technological importance due to the increased industrial applications of these materials. This paper reports the results of potentiodynamic polarization and electrochemical impedance spectroscopic (EIS) measurements on the corrosion inhibition of Al (Al-2.5% Cu and Al-7.0% Cu) alloys in 1.0 M M2SO4 solution carried out in different concentrations of linear-sodium dodecyl benzene sulfonate as an anionic surfactant (LAS) and temperature range from 10 to 60 degrees C. The data revealed that the inhibition efficiency increases with increasing surfactant concentration and time of immersion, and decreases with solution temperature. Energy dispersion X-ray (EDX) observations of the electrode surface confirmed the existence of LAS adsorbed film on the electrode surface. The surfactant acted mainly as cathodic inhibitor. Maximum inhibition efficiency of the surfactant is observed at concentration around its critical micelle concentration (CMC). The inhibition occurs through adsorption of the surfactant on the metal surface without modifying the mechanism of the corrosion process, which tested by UV-spectroscopy. The potential of zero charge (PZC) of aluminum and Al-7.0% Cu was studied by ac-impedance, and the mechanism of adsorption is discussed. The adsorption isotherm is described by Temkin adsorption isotherm. Thermodynamic functions for activation and adsorption process were determined.
10.1016-j.matchemphys.2009.03.036	-1		Present study aims to correlate phase evolution and magnetic properties of Cu-Ni-Co-Fe alloys synthesized by ball milling and isothermal annealing of the ball milled products. Variation of magnetic properties of different alloys has been studied in respect of the chemistry, microstructural constitution and defect concentration. It is observed that in the present Cu-base alloys, stacking/twin fault probabilities are order of magnitude lower than that obtained by ball milling of the elemental constituents (Cu and Co) and hence, their contribution to the magnetic properties is insignificant. It is shown that chemistry of the alloys and size of the constituent phases determined the magnetic behaviour of the alloys. Precipitation of hard magnetic Co in the non-magnetic Cu-matrix has contributed most significantly to the improvement in magnetic properties.
10.1016-j.matchemphys.2009.07.067	-1		This study reports the structural evolution of high-entropy alloys from elemental materials to amorphous phases during mechanical alloying, and further, to equilibrium phases during subsequent thermal annealing. Four alloys from quaternary CU0.5NiAlCo to septenary CU0.5NiAlCoCrFeTi were analyMicrostructure examinations reveal that during mechanical alloying, Cu and Ni first formed a solid solution, and then other elements gradually dissolved into the solid solution which was finally transformed into amorphous structures after prolonged milling. During thermal annealing, recovery of the ary phous powders begins at 100 degrees C, crystallization occurs at 250-280 degrees C, and precipitation and grain groof equilibrium phases occur at higher temperatures. The glass transition temperature usually observed in bulk amorphous alloys was not observed in the present amorphous phases. These structural ev, tion reveal three physical significances for high-entropy alloys: (1) the annealed state of amorphous powders produces simple equilibrium solid solution phases instead of complex phases, confirming high-entropy effect; (2) amorphization caused by mechanical milling still meets the minimum criteria for amorphization based on topological instability proposed by Egami; and (3) the nonexistence glass transition temperature suggests that Inoue's rules for bulk amorphous alloys are still crucial for existence of glass transition for a high-entropy amorphous alloy.
10.1016-j.matchemphys.2009.12.011	2	corrosion; surface; film; electrochemical; films; spectroscopy; layer; current; solution; potential; resistance; composition; x-ray; ions; showed	Corrosion inhibition of Cu-30Ni alloy in aerated 0.5 M H2SO4 solution by cysteine, an amino acid, has been investigated. Potentiodynamic polarization and impedance spectroscopy (EIS) at open circuit potential were performed. Corrosion current density was also determined from colorimetric experiments. Voltammetric curves showed that cysteine addition to 0.5 M H2SO4 affects largely the cathodic process; shifting the corrosion potential to more negative values and decreasing significantly the corrosion current density. The inhibiting efficiency reaches a value of 91% at an inhibitor concentration of 10(-3) M. Impedance data reveal the adsorption of the inhibitor and the surface relaxation process due to nickel. Polarization resistance deduced from impedance measurements or voltammetric experiments are in a good agreement.
10.1016-j.matchemphys.2010.09.077	1	shape; memory; shape memory; damping; martensite; martensitic; damping capacity; transformation; capacity; strain; superelasticity; temperature; cu-al-mn; shape memory effect; effect	Cu-XAl-4Ni shape memory alloys (SMAs) are capable of martensitic transformation across a wide temperature range through the precise adjustment of their chemical composition from X = 13.0 to 14.5. In addition, the variations in chemical composition significantly influence the internal friction characteristics of Cu-XAl-4Ni SMAs. Cu-XAl-4Ni SMAs with a higher content of Al exhibit lower internal friction peaks due to decreases in the amount of transformed martensite and the formation of gamma(2) phase precipitates. The damping capacity of the inherent and intrinsic internal friction for Cu-13.5Al-4Ni SMA is extremely low due to the fact that the transformed beta'(1) (18R) martensite has only an ordered OR structure with stacking faults. The Cu-14.0Al-4Ni SMA exhibits a relative increase in the inherent and intrinsic damping capacity because the transformed gamma'(1) (2H) martensite exhibits twinning with abundant moveable twin boundaries.
10.1016-j.matchemphys.2011.02.005	-1		Using the large-scale atomic/molecular massively parallel simulator, the quantitative composition-structure-properties (including glass-forming ability (GFA) and mechanical behavior) correlations in the Cu-Zr metallic glasses were established. The atomic-level origin of these correlations was tracked down. It was found that the Cu-centered full icosahedron is the microscopic factor that fundamentally influences both GFA and mechanical behavior. Our findings have implications for understanding the nature, forming ability and properties of metallic glasses, and for searching novel metallic glasses with unique functional properties.
10.1016-j.matchemphys.2011.03.003	-1		In the present work, the wettability and interface thermal resistance (ITR) of copper/graphite (Cu/Gr) system with an addition of chromium (Cr) was studied. First, alloy element of Cr (1.0 wt%) was introduced in copper to improve the wettability of Cu/Gr system. The wetting procedure of liquid Cu-Cr alloy on graphite substrate was studied by sessile drop method. It was found that the contact angle decreased to 43 degrees with addition of Cr. Then, an experimental method was employed to determine the FUR of Cu/Gr system. Results reveal that the ITR decreased significantly with the introducing of Cr. It suggested that the reduction of FUR related to the formation of a continuous carbide layer at the interface zone which consisted of Cr7C3 and Cr3C2.
10.1016-j.matchemphys.2011.05.053	2	corrosion; surface; film; electrochemical; films; spectroscopy; layer; current; solution; potential; resistance; composition; x-ray; ions; showed	Superhydrophobic surface was prepared via immersing the clean perpendicular zinc substrate into aqueous copper (II) chloride (CuCl2) solution and followed by anneal under the humid condition. The prepared samples were characterized by powder X-ray diffraction analysis, X-ray photoelectron spectroscopy, energy-dispersive X-ray spectroscopy (XPS), and scanning electron microscopy (SEM), and energy-dispersive X-ray spectrometry analysis (EDX). SEM images of the films showed that the resulted surfaces exhibit micro-nano binary structures. The resulting surfaces had a high water contact angle (CA) of larger than 150 degrees as well as a small sliding angle (SA) of less than 6 degrees. Cu-Zn alloy formed by chemical displacement. Crystal CuZn5 formed via crystal transition via anneal treatment. Crystal ZnO formed in air or under the humid condition. The CuZn5-ZnO micro-nano binary structures leads to the surface superhydrophobicity.
10.1016-j.matchemphys.2011.10.019	-1		A new short flow technique combining in situ reaction and rapid solidification has been developed and used to prepare Cu-TiB2 (0.45, 1.6 and 2.5 wt% TiB2) alloys. The effects of in situ reaction conditions, cooling rate and solute concentration on the microstructure change of Cu-TiB2 alloys were systematically investigated and analyzed by modeling. It is shown that the size and distribution of TiB2 particles are strongly dependent on the choice of reactor shape, in situ reaction conditions and solute concentration, specifically, the size and aggregation level of TiB2 particles tend to increase as increasing normal volume percent of TiB2 particles when the same in situ reaction condition is used. Some different in situ reaction mechanisms, based on the microstructure change and TiB2 particle distribution under different conditions, were also established and analyzed, which can be used to quantitatively predict the size of melt micelles needed for synthesizing uniformly distributed TiB2 particles with different sizes in the copper matrix.
10.1016-j.matchemphys.2011.11.005	16	wear; composite; composites; powders; milling; particles; powder; wt; sliding; friction; hardness; matrix; mechanical; surface; properties	Cu-4.5Cr and Cu-4.5Cr-3Ag (in wt%) alloys without or with 10 wt% nanocrystalline Al2O3 and ZrO2 dispersion have been synthesized by mechanical alloying or milling and consolidated by laser assisted sintering in Ar atmosphere. Microstructural characterization by scanning and transmission electron microscopy and phase analysis by X-ray diffraction suggest that the alloyed matrix undergoes significant grain growth after sintering while the dispersoids retain their ultrafine size and uniform distribution in the matrix. The dispersion of nano-Al2O3 is more effective than that of nano-ZrO2 in enhancing the mechanical properties due to the smaller initial particle size of Al2O3 than that of ZrO2. In general, laser sintering of mechanically alloyed Cu-4.5Cr and Cu-4.5Cr-3Ag alloys with 10 wt% nanocrystalline Al2O3 at 100W laser power and 1-2 mm s(-1) scan speed yields the optimum combination of high density (7.1-7.5 mg m(-3)), hardness (165-225 VHN), wear resistance and electrical conductivity (13-20% IACS).
10.1016-j.matchemphys.2012.03.094	-1		Cu55Zr35Ti10 (at. %) ribbon was prepared by melt spinning. Its glassy structure was confirmed by X-ray diffraction (XRD) and differential scanning calorimetry (DSC), respectively. Its corrosion behavior in HCl and NaCl solutions was investigated by electrochemical polarization and immersion measurements. The surfaces before and after corrosion were observed with scanning electron microscope (SEM). The corrosion potential and corrosion resistance of the Cu55Zr35Ti10 metallic glass both decrease with increasing chloride concentration, and are higher in NaCl than in HCl. The current density in anodic curve sharply decreases when the potential reaches up to a value and the chloride concentration is more than 0.5 M in both HCl and NaCl solutions. The different corrosion behavior in HCl and NaCl is also carefully discussed.
10.1016-j.matchemphys.2014.03.060	16	wear; composite; composites; powders; milling; particles; powder; wt; sliding; friction; hardness; matrix; mechanical; surface; properties	This work discusses the extension of solid solubility of Cr and Mo in Cu processed by mechanical alloying. Three alloys processed, Cu-5Cr-5Mo, Cu-10Cr-10Mo and Cu-15Cr-15Mo (weight%) using a SPEX mill. Gibbs free energy of mixing values 10, 15 and 20 kJ mol(-1) were calculated for these three alloys respectively by using the Miedema's model. The crystallite size decreases and dislocation density increases when the milling time increases, so Gibbs free energy storage in powders increases by the presence of crystalline defects. The energy produced by crystallite boundaries and strain dislocations were estimated and compared with Gibbs free energy of mixing values. The energy storage values by the presence of crystalline defects were higher than Gibbs free energy of mixing at 120 h for Cu-5Cr-5Mo, 130 h for Cu-10Cr-10Mo and 150 h for Cu-15Cr-15Mo. During milling, crystalline defects are produced that increases the Gibbs free energy storage and thus the Gibbs free energy curves are moved upwards and hence the solubility limit changes. Therefore, the three alloys form solid solutions after these milling time, which are supported with the XRD results.
10.1016-j.matchemphys.2014.11.060	11	glass; bulk; metallic; bulk metallic; gfa; bmg; glassy; metallic glass; ability; bulk metallic glass; amorphous; addition; crystallization; mm; glass-forming	Glass forming ability, thermal, electrical and mechanical properties of Cu50Zr40Ti10-xNix (0 <= x <= 4.0 at%) glass forming alloys were systemically investigated. It is found that the critical dimension of the present Cu-based glass forming alloys firstly increases with increasing Ni content, then decreases when Ni >2.0 at%. Ni addition results in the increase of the electrical resistivity and the thermal conductivity. The glass transition temperature increases with increasing Ni content for the present Cu-based BMGs at all studied heating rates. However, there are complex correlations for the other characteristic temperatures, crystallization enthalpy and activation energy with the Ni content and heating rate, respectively. The plastic strain firstly increases with increasing Ni content, then decreases when Ni >2.0 at%. Both yield strength and compression strength nearly increase with increasing Ni content. The plastic strain increases with decreasing m in the range of 0 <= Ni <= 2.0 at% and 2.0 <= Ni <= 4.0 at% for present Cu-based BMGs. The m linearly decreases with increasing d(c) for the present cu-based BMGs. The corresponding mechanisms are also investigated.
10.1016-j.matchemphys.2014.12.032	12	thermodynamic; ternary; phase; data; experimental; equilibria; phase equilibria; liquid; binary; experimental data; calculated; phases; literature; model; calphad	A complete thermodynamic description of the Cu-Ni-Y ternary system has been obtained using the CALPHAD (CALculation of PHAse Diagram) approach . Ternary solubility of the third element in the binary compounds in the Cu-Ni-Y system is described using sublattice model within the compound energy formalism (CEF) to take into account the recently reported experimental solubility ranges. The modified quasi-chemical model (MQM) has been used to describe the liquid phase in order to account for the presence of short range ordering properly. To study the melting behavior of the Cu-Ni-Y alloys and to verify the consistency of the thermodynamic model with experimental results, 10 key samples were prepared and the phase transformation temperature's were measured using differential scanning calorimeter (DSC). The microstructural characterization and crystallographic analysis of the alloys were carried out using scanning electron microscopy (SEM) coupled with WDS analysis and X-ray diffraction (XRD). Several vertical sections, liquidus projection and isothermal section at 973 K have been calculated and found to be in good agreement with the current experimental data as well as with the literature.
10.1016-j.matchemphys.2016.02.009	2	corrosion; surface; film; electrochemical; films; spectroscopy; layer; current; solution; potential; resistance; composition; x-ray; ions; showed	The electrode potential or galvanic series is usually used to reflect the nobility of metals and semi-metals. However, this potential is environment-dependent and the intrinsic nobility of a metal is ultimately governed by its electron stability, which can be represented by the electron work function (EWF). This article reports our studies on the corrosion behavior of isomorphous Cu-Ni alloy in HCl and NaCl solutions, respectively. It was demonstrated that the EWF of the alloy increased as the Ni concentration was increased, so did the corrosion resistance in the acidic solution. In the sodium chloride solution, however, the trend was reversed due to adsorption, hydrolysis and the formation of oxide scale on Cu-rich samples, which more or less prevented them from further corrosion in this solution. In order to confirm this, corrosive wear tests were performed to analyze the performance of the alloy when the effect of oxide scale was eliminated or minimized by the mechanical action.
10.1016-j.matchemphys.2016.02.048	-1		In the present work a detailed study of the surface morphology of purposely-prepared Cu-Ni reference alloys has been performed. These alloys have been prepared via tailored casting methods in order to have samples with same chemical composition and different local chemical enrichments of both metals. A micro-LIBS system for surface spatial scanning was set up based on a second harmonic Nd:YAG laser at 532 nm and using a focusing lens of focal length 7 cm to disclose the local chemical composition variation. Surface morphological scanning was performed for some of the binary Cu-Ni reference alloys to differentiate between chemically homogeneous and heterogeneous alloys. LIBS results were compared with the information of the Scanning Electron Microscope coupled with Energy Dispersive X-ray (SEMEDS) investigation carried out to provide surface local large-area chemical analysis via EDS technique. It has been proved that LIBS is a simple, sensitive and direct technique in the determination of homogeneity or heterogeneity of the sample's surface. The LIBS results have been shown to be more sensitive and accurate in the heterogeneity determination than other used conventional analytical techniques.
10.1016-j.matchemphys.2016.04.004	-1		In order to enhance the electrical sliding wear resistance and hence the lifespan of cp Cu for applications in electrical contacts, W-reinforced Cu layers were fabricated by laser surface modification on cp Cu. Compared with cp Cu, the hardness of the laser-fabricated layers with 55-60 wt% W was improved from 70 to 150 HV0.2 while electrical wear resistances in dry and wet conditions were improved by 3 orders of magnitude despite the increase in the interfacial contact resistance of the layers. The main contribution of electrical wear in synthetic acid rain is mechanical wear, with contribution of corrosion-wear synergism up to 32.8%, while corrosion alone is negligible.
10.1016-j.matchemphys.2016.06.030	16	wear; composite; composites; powders; milling; particles; powder; wt; sliding; friction; hardness; matrix; mechanical; surface; properties	Mechanical alloying was used to produce Cu matrix nanocomposite reinforced by 4 wt% ZrO2 nano particles with different milling time up to 16 h and ball-to-powder ratios (BPRs) up to 40:1. The milled nanocomposite powders were investigated by X-ray diffraction (XRD) technique and transmission electron microscopy (TEM). To study the sinterability, the milled powders were cold pressed and sintered at 800 degrees C for 1 h in argon atmosphere. In order to investigate the relative density and microstructures of the sintered nanocomposites, scanning electron microscopy (SEM) as well as energy dispersive spectrometer (EDS) were employed. The electrical and mechanical properties of the sintered nanocomposites were also examined. The results revealed that a uniform distribution of ZrO2 reinforcement in Cu matrix was successfully obtained and the agglomeration, crystal and particle sizes were decreased after either milling times and/or BPRs. The results also pointed out that the relative density, microhardness, compressive strength and electrical conductivity of the sintered nanocomposite samples were increased with the increasing of milling time and/or BPRs while apparent porosity was decreased. The maximum values of microhardness, compressive strength and electrical conductivity were 872 MPa, 304 MPa and 45.9% IACS, respectively for the milled sample for 16 h and BRP 40:1. (C) 2016 Published by Elsevier B.V.
10.1016-j.matchemphys.2016.12.052	-1		Cu-Mn3O4 composite coatings were prepared on the SUS 430 steel by means of the electrodeposition in an alkaline copper pyrophosphate bath containing Mn3O4 particles. The effect of bath pH on the content of Mn3O4 co-deposited in Cu matrix was investigated by electrochemical measurements including zeta potential, cathodic polarization and electrochemical impedance spectroscopy (EIS). The results showed that pH had a significant influence on co-deposition of Mn3O4 in Cu matrix. It was found that the absolute value of zeta potential of Mn3O4 particle, cathodic overpotential and Faraday resistance reached the maximum when the bath pH was adjusted to 9 or 9.5, which implied that mass fraction of co-deposited Mn3O4 particles in composite coating obtained at pH of 9 or 9.5 would be higher than those at other pH values. The compositions and microstructures of Cu-Mn3O4 composite coatings obtained at different pH values were consistent with the results of electrochemical analyses. The mass fraction of co-deposited Mn3O4 was highest (8.02 wt%) at pH of 9. It was proved that electrochemical tests were of great significance to ascertain suitable pH for Cu-Mn3O4 composite electrodeposition. Scratch test indicated the critical load (L-c) of the composite coating obtained at pH of 9 was 21.4 N.
10.1016-j.matchemphys.2017.06.041	15	aging; strength; conductivity; electrical conductivity; electrical; mpa; treatment; strengthening; degrees; cu-; cold; precipitation; tensile strength; tensile; iacs	The microstructure and corrosion behavior of the Cu-15Ni-8Sn-1.0Zn- 0.8A1-02Si alloy treated with different thermo-mechanical processes in 3.5 wt% NaCl solution was investigated by electrochemical test, electron microscopy and XPS analysis. Compared with single-stage thermo-mechanical treatment (cold rolling by 60% reduction and then aging at 450 degrees C for 0.5 h), the alloy with two-stage treatment (pre aging at 400 degrees C for 0.5 h, cold rolling by 60% reduction and then aging at 450 degrees C for 0.5 h) had finer ordered precipitates and less coarse, discontinuous precipitates, resulting in better corrosion resistance performance. The corrosion product layer was mainly a mixture of Cu2O, CuO, NiO, Ni(OH)(2), SnO, SnO2, ZnO and Al2O3, with a transition from Cu2O to CuO and Cu(OH)(2) occurring during the corrosion process.
10.1016-j.matchemphys.2017.10.071	-1		In order to inhibit Cu, interconnecting in ultra-large-scale integration, from diffusing with surrounding dielectric materials and enhance its chemical inertness and maintain its excellent electrical performance as well. In this paper, the stable solid solution cluster-plus-glue-atom model was used to design the composition of Cu seed layers. In this model, insoluble element V (or Cr) was dissolved in Cu via Ni which is soluble both with Cu and V(or Cr), causing a certain degree of lattice distortion to improve the stability of Cu film. Cu-Ni-V(or Cr) alloy films were deposited directly on single crystal Si(100) substrates, without a designated barrier layer, subsequently annealed in vacuum. For the (V0.8/12.81Ni12/12.8)(0.5)Cu-99.5 (at%) film with the addition of large atomic radius element V, it showed the minimum electrical resistivity of 3.2 mu Omega cm after 500 degrees C/1 h annealing; after 500 degrees C/40 h annealing, no diffusion between Cu and Si was observed and the resistivity remained stable. Likewise, the (Cr1.4/13.4Ni12/13.4)(0.4)Cu-99.6 film also remained a minimum resistivity of 3.0 mu Omega.cm after annealing at 500 degrees C for 40 h . The greater the relative lattice distortion is in a single system, the higher the stability and the lower resistivity achieved. Obviously, the stability of Cu alloy film which satisfy the requirements of the microelectronics industry can be improved dramatically by the additive of Ni and V (or Cr) conform to the proportion of clusters.
10.1016-j.matchemphys.2017.11.058	16	wear; composite; composites; powders; milling; particles; powder; wt; sliding; friction; hardness; matrix; mechanical; surface; properties	Al-4.5 wt% Cu-based nanocomposites, reinforced with various weight percentages of ZrO2, have been synthesized via mechanical alloying method. The mixture powders were cold pressed and sintered at various firing temperatures up to 500 degrees C for 1 h in argon atmosphere. X-ray diffraction technique is utilized to investigate structural phases and elemental diffusion of milled powders. Transmission and scanning electron microscopies coupled with energy dispersive spectroscopy were employed to examine the morphology of milled powders and the microstructure of sintered specimens, respectively. Physical, mechanical and electrical properties of sintered samples were measured. Moreover, the sintered samples followed by heat treatments at 460 degrees C for 3 h, quenched and then, artificial aging was performed. The results revealed that Al2Cu precipitate phase was clearly observed after milling reflecting the formation of supersaturated solution of Cu in Al. Increase of ZrO2 contents caused weakness of Al2Cu phase, decrease in the crystal and particle sizes. Furthermore, successive increase of ZrO2 contents led to, in contrast to relative density and electrical conductivity, remarkable enhancement of mechanical properties of the nanocomposites. The results pointed out that microhardness, compressive strength and conductivity, for specific ZrO2 content, obviously increased at the early stage of aging and then, decreased.
10.1016-j.matchemphys.2017.12.087	2	corrosion; surface; film; electrochemical; films; spectroscopy; layer; current; solution; potential; resistance; composition; x-ray; ions; showed	The peculiar behaviour of zinc depending on whether it is used pure or alloyed in Cu63Zn37 wire electrodes leads either to nanosheets or to nanoparticles when it is processed by nanosecond pulsed discharges in liquid nitrogen. Using one electrode of copper and one electrode of zinc gives core-shell Cu@Zn nanoparticles but no alloy for the smallest nanoparticles (typically below 20 nm). Once nitrogen is evaporated, their oxidization in air produces Cu2O@ZnO nanoparticles. If both electrodes are made of Cu63Zn37, then the smallest nanoparticles are made of Cu and Zn and oxidized next in air to give Cu2O and ZnO nanoparticles. No alloy is formed either. Time-resolved optical emission spectroscopy gives clues on the origin of such behaviours, explaining why no alloy is formed when electrodes are made of different materials.
10.1016-j.matchemphys.2018.01.072	4	transformation; martensite; martensitic; phase; shape; beta; memory; shape memory; temperature; temperatures; martensitic transformation; gamma; transformation temperatures; effect; thermal	The thermomagnetic behavior of the as-quenched Cu-9wt%Al-10 wt%Mn-3wt%Gd alloy was studied using differential scanning calorimetry (DSC), optical microscopy, magnetization measurements with temperature and applied field. The results obtained showed that in the Cu-9wt%Al alloy the alpha, gamma(1) and alpha(2) phases are produced from martensitic beta' phase decomposition while in the Cu-9wt%Al-3wt%Gd alloy the higher fraction of produced gamma(1) phase is not formed from martensite decomposition. In the Cu-9wt%Al-10 wt%Mn and Cu-9wt%Al-10 wt%Mn-3wt%Gd alloys the ferromagnetic Cu2AlMn phase formation is dependent on the cooling rate and the martensitic transition seems to be changed by the presence of Gd.
10.1016-j.matchemphys.2018.07.017	-1		Cu-based bearing shell containing Ni layer was prepared by centrifugal casting. The effect of Ni layer on the microstructure evolution and mechanical property of Cu-based bearing shell with aging treatment was studied. The microstructure of the Sn-Sb-Cu alloy (ZChSnSbCu8-4) without aging is consisted of Sn-based solid solution and Cu6Sn5 phases which distributed uniformly in the matrix. After aging treatment, the grain boundary segregation is slowly disappeared, and the matrix transforms into a more uniform Sn-based solid solution. The Ni layer hinders the diffusion of Cu and Sn atoms at the interface, and suppresses the volume fraction increment of Cu6Sn5 phase during aging. The Cu6Sn5 phases are gradually coarsened during aging. The average bonding strength of Cu-based bearing shell with Ni layer is 70.3 MPa. After aging at 175 degrees C with 500 h, the bond strength is still higher than 50 MPa, which is greater than the specimen without Ni layer. The hardness of Cu matrix, Ni layer and Sn-Sb-Cu alloy decreases with increasing aging time. While the hardness of the region near the Ni/Sn-Sb-Cu interface increases from 47.5HV to 88.4HV during aging. The fracture surface of the samples after aging treatment is changed from intergranular/transgranular fracture mode to intergranular fracture mode. The change of the fracture mode is related to the coarsening and growth of Cu6Sn5 phases near the interface between Ni layer and Sn-Sb-Cu matrix.
10.1016-j.matchemphys.2018.08.067	2	corrosion; surface; film; electrochemical; films; spectroscopy; layer; current; solution; potential; resistance; composition; x-ray; ions; showed	Black Cu-Sn alloy coating was prepared from 1-butyl-3-methylimidazolium chloride ([BMIM]Cl) ionic liquids by electrodeposition method. The electrochemical behaviors of different electrodeposition systems were investigated by cyclic voltammetry. The micromorphology of the black coating was investigated by scanning electron microscopy (SEM) coupled with energy dispersive spectrometer (EDS) and X-ray diffraction (XRD). The results showed that black coating was cypress leaf-like material. The electrochemical behavior in [BMIM]Cl-CuCl2 center dot 2H(2)O-SnCl2 center dot 2H(2)O ionic liquids showed the peak located at -0.5 V similar to -1.0 V belonged to the reduction peak of coppe-tin alloy co-deposition. The element compositions of coating were Cu and Sn, and the phase composition of the coating was Cu-13.7 Sn. center dot
10.1016-j.matchemphys.2018.09.048	-1		In this paper, the high performance Cu-Fe-P alloys with ultra-fine grain and nanocrystalline structure were successfully prepared by mechanical alloying (MA) and reactive hot-pressing (RHP). Then the combined effects of sintering temperature and phosphorus content on microstructure and properties were investigated. The results showed that phosphorus had a positive effect on the performance of Cu-Fe-P alloy. It could reduce the content of iron doped in the Cu matrix rather than forming precipitates such as Fe3P or Fe2P. Moreover, the ultra-fine grain and nanocrystalline structure had a great effect on performance of the alloys. The crystallite size of the Cu-Fe-P alloys exhibited average value of 10 nm after milling for 4 h by TEM. The lower sintering temperature was better to retain the size of nanoparticles and achieve excellent performance. Consequently, the best performance was achieved by the Cu-Fe-0.025P sintered at 600 degrees C and ball-milled for 4 h . The electrical conductivity reached 80.41% IACS with the tensile strength of 517 MPa which was much better than the conventional Cu-Fe-P alloy.
10.1016-j.matchemphys.2019.02.016	4	transformation; martensite; martensitic; phase; shape; beta; memory; shape memory; temperature; temperatures; martensitic transformation; gamma; transformation temperatures; effect; thermal	The effects of Ag additions on phases separation and order-disorder transitions in the Cu-7Al-10Mn, Cu-9Al-10Mn and Cu-11Al-10Mn alloys have been studied using electrical resistivity measurements with temperature, differential scanning calorimetry, scanning electron and transmission electron microscopies, X-ray diffractometry and electron diffraction analysis. The results indicated that the decrease in Al content reduces the Cu2AlMn phase amount produced on slow cooling. It was also verified that the variation in Al fraction and Ag addition modify the order-disorder transitions temperatures. A schematic phase diagram showing the shift of phases field with addition of Ag has been proposed.
10.1016-j.matchemphys.2019.04.078	2	corrosion; surface; film; electrochemical; films; spectroscopy; layer; current; solution; potential; resistance; composition; x-ray; ions; showed	This paper reports the development of mechanically flexible reflective coatings of Cu-Al intermetallic alloy on flexible glass (PG) substrates for possible concentrated solar power application. Thin films of Cu-Al intermetallic alloys were deposited on 100 mu m thick FG substrates using resistive thermal evaporation of arc melted Cu-Al bulk alloy. At the optimized evaporation conditions, smooth intermetallic alloy thin films with homogeneous composition (Cu0.78Al0.22) were obtained. At a coating thickness of 160 nm, average specular and total reflectance of similar to 84% and similar to 92% respectively, were achieved. The films exhibited hydrophobic nature with a contact angle of 102 degrees, implying the possibility of developing a self-cleaning ability. The analytical calculation involving alloy compositional dependence of plasma frequency reveals the prospect of further modulating the reflectance property by carefully tailoring thin film composition. Additionally, hard intermetallic thin film provides the opportunity of developing mirrors that may not require top protective coatings.
10.1016-j.matchemphys.2019.04.092	12	thermodynamic; ternary; phase; data; experimental; equilibria; phase equilibria; liquid; binary; experimental data; calculated; phases; literature; model; calphad	The Cu-Ta system is a simple binary system with interesting properties, such as the formation of amorphous alloys and high-energy mechanical alloying capacity. Due to a high melting temperature of tantalum, experimental information about phase diagram is limited to one liquidus point. The ab initio and molecular dynamics approaches were used in this work for determination of thermodynamic properties of solid and liquid phases of Cu-Ta system. After that, the phase diagram was modeled with the aid of the Calphad method. As a consequence of these steps, a new thermodynamic description of the Cu-Ta system is proposed in this paper.
10.1016-j.matchemphys.2019.05.030	11	glass; bulk; metallic; bulk metallic; gfa; bmg; glassy; metallic glass; ability; bulk metallic glass; amorphous; addition; crystallization; mm; glass-forming	(Cu50Zr50)(x)(Cu73Ti27)(100-x) (x = 0.63-0.75 at%) alloys are designed using the proportional mixing of Cu(50)Zr(50 )and Cu73Ti27 binary alloys. Their thermal, mechanical and corrosive properties as well as the glass forming ability (GFA) are systematically investigated. The results show that the studied Cu-based glass forming alloys are bulk metallic glass composites (BMGCs) with off-eutectic compositions and display work-hardening behavior. The glass transition temperature and the reduced glass transition temperature increase and then decrease with increasing x when x >= 0.74 atop, while on the contrary for the critical cooling rate and supercooled liquid region. Both yield strength and fracture strength firstly increase and then decrease with decreasing x when x <= 0.71 at%. The plastic strain of (Cu50Zr50)(0.)(75)(Cu73Ti27)(0.)(25) BMGC is the largest among the studied Cu-based BMGCs. Potentiodynamic polarization measurements show that all studied BMGCs exhibit a step-like anodic polarization behavior, indicating two competitive procedures of pitting corrosion and self-passivization. The corrosion behavior gradually transforms from predominant self-passivization to the pitting corrosion with decreasing x. Both corrosion current density and onset passive current density of (Cu50Zr50)(0.)(75)(Cu73Ti27)(0.)(25) BMGCs are two orders of magnitude lower than those of the other Cu-based BMGCs. The mechanisms for the GFA and the corrosion are also discussed. The present work would shed light on how to design and develop BMGCs with superior comprehensive performances.
10.1016-j.matchemphys.2019.121909	-1		Immiscible Cu-Fe alloy shows great potential to be applied as soft magnetic material. in the current study, the as-solidified immiscible Cu-Fe alloys were firstly investigated to uncover the correlation between Fe content (10-40 wt%) and its corresponding microstructure evolution and magnetic properties. The present observation revealed that the increasing Fe content results in a significant change in Fe-rich dendrites morphology and grain size of Cu-Fe alloy, which should be responsible for both improvement in the saturated magnetization and coercivity of the alloy. After subsequent annealing treatment (950 degrees C, 4 h), a considerable amount of Fe-rich nano-particles (alpha-Fe) and Cu-rich phases precipitate from the Cu matrix and Fe-rich dendrite, consequently giving rise to both enhancement of saturated magnetization and coercivity. In general, it was demonstrated that the soft magnetic property of Cu-Fe alloy can be enhanced via annealing treatment with improving the saturated magnetization and slightly deteriorating coercivity. To the best of our knowledge, the as-prepared Cu-Fe alloy can exhibit an excellent soft ferromagnetic characteristic (saturated magnetization Ms 76.8216 emu/g and coercivity Hc 24.613 Oe). Additionally, the current research provides profound guidance and knowledge for tailoring magnetic properties of immiscible Cu-Fe alloy for industrial applications as a promising soft magnetic material.
10.1016-j.matchemphys.2019.121912	6	grain; deformation; strain; strength; dislocation; cu-; tensile; size; ecap; grain size; sfe; ductility; hardening; high; stress	Constrained groove pressing (CGP) is a severe plastic deformation (SPD) technique which results in enhanced strength of materials, however, it is also known that this technique leads to inhomogeneity and anisotropy in materials' properties owing to the geometry of CGP die used. Microstructural, as well as strain inhomogeneity, can be alleviated by inducing discontinuous recrystallization, but this may also lead to decrease in strength . In this work, a Cu-Zn alloy was processed through CGP for a single pass and then heat treated at 700 degrees C for short durations of 1, 2, 4, and 10 min. The aim of the work is to examine the influence of short heat-treatment (SHT) on microstructural evolution and mechanical behavior of single pass CGP processed Cu-Zn alloy. It was found that SHT at 700 degrees C induces recrystallization and leads to homogenization of microstructure and materials' properties. Tensile test showed that constrained groove pressed sample and the sample heat-treated for 1 min fractured before attaining the necking zone, which can be directly related to the presence of voids or micro-cracks while samples heat treated beyond 1 min showed the necking. It was found that recrystallization leads to healing of internal voids or micro-cracks, which results in high ductility for samples given SHT beyond 1 min. Strain hardening behavior of various sample conditions was also examined, and it was found that heat-treatment of 2 min and longer duration completely transforms the hardening behavior of severely deformed samples. This implies that a minimum fraction of recrystallization is required for healing of voids/micro-cracks to alleviate the problem of premature fracture. We further analyzed the thermal stability of partially recrystallized samples and found these to be stable up to 300 degrees C. This study shows that post-process heat-treatment can be used as a design tool for severely deformed materials to obtain tailored microstructures with desired properties.
10.1016-j.matchemphys.2019.122343	4	transformation; martensite; martensitic; phase; shape; beta; memory; shape memory; temperature; temperatures; martensitic transformation; gamma; transformation temperatures; effect; thermal	In this work, the effects of Zr additions on the microstructure and phase stability of the initially annealed Cu-9Al-10Mn-3Ag alloy were studied using optical microscopy (OM), differential thermal analysis (DTA), microhardness measurements, scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDX), X-ray diffraction (XRD), differential scanning calorimetry (DSC), and magnetization measurements as a function of temperature and applied field. The results showed that the increase in Zr concentration decreased the alpha-Cu phase grain size and increased the alloys microhardness. The Curie temperature of the alloy was not modified by the Zr additions. Moreover, the precipitation of Ag-rich phase occurred preferentially at the intergranular region and the addition of 5%Zr increased the melting temperature of the Cu-9Al-10Mn-3Ag alloy and contributed for the formation of the Cu2ZrAl phase. A mechanism was proposed for the Cu2ZrAl phase formation in the Cu-9Al-10Mn-3Ag-5Zr alloy.
10.1016-j.matchemphys.2020.123708	16	wear; composite; composites; powders; milling; particles; powder; wt; sliding; friction; hardness; matrix; mechanical; surface; properties	Nanostructured Cu98Cr2-W composite powder was synthesized by high-energy ball milling and consolidated by spark plasma sintering (SPS). For comparison, pure Cu and Cu98Cr2 composite were also prepared under similar condition. Phase and microstructural characterization was carried out by X-ray diffraction (XRD) and transmission electron microscopy (TEM). Hardness, wear property and electrical conductivity of the composite was evaluated and compared with pure Cu and Cu98Cr2 composite. The Cu98Cr2-W composite, show similar to 5% and similar to 21% higher hardness compared to Cu98Cr2 and pure Cu respectively. It also shows significant improvement in wear property and electrical conductivity, which makes the newly developed composite a potentially better candidate for high voltage circuit breaker application over existing Cu-Cr based composites.
10.1016-j.matchemphys.2020.123720	16	wear; composite; composites; powders; milling; particles; powder; wt; sliding; friction; hardness; matrix; mechanical; surface; properties	In the present study, Cu/SiC surface composite was fabricated by friction stir processing (FSP) via multi-groove technique eyeing to improve SiC dispersion in copper matrix and hence improving mechanical and tribological behaviour. Microstructural features revealed more uniform dispersion of SiC particles in copper matrix when fabricated through multi-groove technique (MGT) as compared to single groove technique (SGT). The interface between copper matrix and SiC particles were clean without any obstruction/interruption in the form of voids or pores or intermediate phases formed which indicated excellent interfacial bonding. Furthermore, the obtained microstructure revealed drastic grain refinement in FSPed copper without reinforcement and the composites fabricated through SGT and MGT and the reduction in grain size was more for the composites fabricated by MGT. Tensile tests revealed incremental behaviour over strength with increase in number of grooves although it was far less as compared to base copper. Fractured surfaces of composites fabricated by both techniques (SGT and MGT) indicated reduction in ductility. However, results obtained for FSPed copper without reinforcement showed higher strength and ductility as compared to base copper. It was also demonstrated that incorporation of SiC particles in copper matrix improved hardness and wear resistance and it further enhanced with increased number of grooves. The wear mechanism changed with introduction of SiC particles in copper matrix and was supposed to be because of reduction in friction coefficient.
10.1016-j.matchemphys.2021.124270	-1		Molecular dynamics simulations have been conducted to find out the cohesion property, tensile strength, and ( ) dislocation evolution of several Cu-Fe interfaces. It is found that Cu 111 /Fe(110)-KS and Cu(111)/Fe(110)-NW interfaces are not only energetically favorable with lower interface energies, but also have higher strength than Cu-Fe interfaces with other interface orientations. Simulations also reveal that the formation of Cu-Fe interfaces has an important effect to increase the tensile strength of Cu under tensile loading along the directions parallel to the interface due to the block of the dislocation movement by the interface. On the contrary, the tensile strength of the Cu-Fe interfaces is smaller than that of Cu along the direction perpendicular to the interface as a result of the weak interface cohesion. The simulated results are in good agreement with experimental observations in the literature, and could provide a deep understanding of mechanical property and dislocation evolution of Cu-Fe interfaces.
10.1016-j.matchemphys.2021.124517	9	magnetic; magnetization; magnetoresistance; temperature; superparamagnetic; annealing; gmr; field; magnetic properties; ferromagnetic; granular; samples; magnetic field; melt-spun; particles	This work has investigated the microstructure and magnetic properties of supersaturated melt-spun Cu?10%Co alloys by means of magnetization, magnetotransport studies, electron microscopy and electron holography. Our results demonstrate that the microstructure of the annealed supersaturated alloys is constituted by two different types of Co-rich phases: spherical Co-rich precipitates as a result of spinodal decomposition, and Co rod-like precipitates, as a result of discontinuous grain-boundary precipitation. The aspect ratio of such precipitates is quite high, exhibiting magnetic anisotropy along their long axes, which generates global anisotropy of the alloy sample. We verified that the highest giant magnetoresistance occurs concurrently with an optimum discontinuous precipitate development. Electron holography reveals an antiferromagnetic coupling of the Co rods in the remanent magnetization state. The magnetization and magnetoresistance curves as a function of applied magnetic field are well described by an independent-moment approach considering the sum of the average magnetic moments of the spherical and the rod-like Co precipitates.
10.1016-j.matchemphys.2021.124942	-1		Cu-Ni-Si powder compacts were firstly prepared by mechanical mixing and cold-pressing, and then held at 600, 700, 800, 900, 950 and 1000 degrees C for 5 min followed by water-quenching. Subsequently, X-ray diffraction (XRD), scanning electron microscope (SEM), energy dispersive spectrometer (EDS) and transmission electron microscope (TEM) were used to characterize the microstructure and phase composition of water-quenched samples, and competitive reactions among Ni-Si compounds were also discussed. Finally, a schematic diagram about the solid-state reaction process of Cu-Ni-Si powder system was proposed. Results showed that Ni and Si substances started to diffuse and reacted when the temperature was above 600 degrees C, resulting in the formations of Ni31Si12 phase at the primary powder boundary and Ni2Si precipitations inside the Cu powder, respectively. With the increase of temperature, Ni2Si phase dissolved into Cu matrix while the amount and size of Ni31Si12 phase increased along with the morphology changing from chrysanthemum-like shape to equiaxed structure. The final microstructure of Cu-Ni-Si powder system after sintering and water quenching consisted of Cu(Ni,Si) solid solution and equiaxed Ni31Si12 phase at the primary powder boundary, which was expected to achieve a combination of high strength and high electrical conductivity by subsequent heat treatments.
10.1016-j.matchemphys.2022.125835	-1		Cu51Zr14 intermetallic inoculant was adopted to effectively decrease the grain size of a Cu-Al-Mn shape memory alloy (SMA), and key factors affecting the refining effect were systemically investigated. It is found that the important prerequisite for grain refinement of this alloy is that the Cu51Zr14 inoculant can provide effective heterogeneous nucleating centers, and the size of the spherical cap of the Cu-Al-Mn nuclei formed on these centers can reach the critical nucleus radius under a certain undercooling degree. The size of inoculant, the temperature and time of inoculation are all important factors affecting the refining effect. When the Cu51Zr14 inoculant was mechanically crushed into small pieces with the size ranged from 0.05 mm to 1 mm, and the temperature and time of inoculation are 1100 degrees C and 6 min, respectively, the best refining effect and the highest damping and mechanical properties can be achieved. The correlated mechanisms have been discussed in detail. The results of this work nicely provide an important theoretical base for the research, development as well as application of high damping performance alloys.
10.1016-j.matchemphys.2022.125892	16	wear; composite; composites; powders; milling; particles; powder; wt; sliding; friction; hardness; matrix; mechanical; surface; properties	In this study, electrolytic copper powders (ECs) were fabricated by electrolysis method using scrap copper pieces as the main material. Copper-silver bimetallic powders (ESCs) were obtained by electroless silver coating process. Then, copper-silver layered materials (ESC materials) with different process parameters were fabricated by using the hot-pressing method. The effects of hot-pressing temperature (25, 200, 400, 500 and 550 degrees C) and pressures (400, 500 and 600 MPa) on the properties of ESC materials were investigated. Morpholological examination of ECs and ESCs and microstructure examination of layered copper-silver materials was performed using scanning electron microscopy (SEM). Electrical and thermal conductivity, hardness and density of the materials produced with different hot-pressing parameters were examined. According to the results, it was determined that materials with the best physical and mechanical properties were obtained when the temperature used in hot- pressing was 500 degrees C and the pressure was 600 MPa. In materials produced at higher temperatures and pressures, a decrease in electrical and thermal conductivity values was determined as a result of the increase in deformation.
10.1016-j.matchemphys.2022.126246	17	wear; composites; coating; friction; composite; coatings; surface; tribological; properties; wear resistance; resistance; powder; sliding; matrix; wear rate	In this study, the feasibility of preparing copper foil by treating cuprous sulfide superionic conductor with electric field was investigated. The original cuprous sulfide powder was first loaded into the mold, then sandwiched between two electrodes, and then subjected to electropulsing treatment, in which process copper foil grown on the spacer at the cathode. Copper foil with smooth, complete and uniform thickness (the thinnest one is 18 mu m) was successfully prepared. The addition of alloying elements in the original powder affected the copper precipitation. The basic factors determining the thickness, flatness and integrity of copper foil is the copper concentration caused by electric field at the cathode end of the copper sulfide block and the energy barrier of copper precipitation in cuprous sulfide matrix and interface. The processing conditions that will affect these fundamental factors will affect the characteristics of the formed Cu foil. Electropulsing processing of superionic conductor provides a new option for the preparation of high-quality Cu foil, which is expected to be used in lithium batteries and printed circuit boards. This method is also applicable to the preparation of other kinds of metal foils.
10.1016-j.matchemphys.2022.126378	-1		To investigate the service stability, the plasma cladding Ni60A coating on copper surface was heat-treated at 600 degrees C for a long time in air. The evolution of the surface morphology, microstructure, hardness and wear resistance of the coating was systematically investigated. After heat treatment, a thin NiO oxide layer formed on the coating surface, but its thickness did not increase with the extension of heat treatment time, indicating the good oxidation resistance of the coating. Heat treatment had no obvious effect on the phase composition and distribution of the coating. Only the crystal grains of gamma-(Cu, Fe, Ni) solid solution and part of Cr23C6 reinforcing phase tended to grow up under the action of heat. The coarsening of the microstructure led to a slight decrease in hardness and wear resistance. The thin NiO oxide layer had less protective effect on the coating surface, because it was easily damaged during the friction process. Compared with the coating before heat treatment, the wear resistance after heat treatment for 30 days was only reduced by 1.3 times, which was still 3.95 times that of the copper substrate, indicating that the coating can basically maintain good stability in a high-temperature air environment.
10.1016-j.matchemphys.2022.126630	-1		Although nanostructured Cu alloys prepared show great advantages in performance, the excellent properties have not been achieved at present primarily due to a single strengthening method or the Fe contamination introduced during mechanical alloying. In the present work, an appropriate amount of Zr was added to adjust the milling process and Fe contamination in the Cu matrix. Then the effects of Zr on the morphologies, crystallite sizes, lattice strain, composition and properties were analyzed. When the added Zr content was 0.1 wt%, it could promote the work hardening of Cu powders, resulting in smaller crystallite sizes, larger internal strain. And a slightly higher Fe content was introduced. However, with the increase of the Zr content, the Fe contamination was reduced obviously and the crystallite size began to increase again. Even so, the average crystallite sizes of nanostructured Cu alloys were still less than 20 nm. The results also showed that MA could increase the solid solubility of Zr in Cu. In a word, the properties of the nanostructured Cu alloys were improved by the refinement strengthening of matrix, solid solution and dispersion strengthening of Fe and Zr. The optimum properties were achieved by Cu-0.1 wt% Zr with electrical conductivity of 75.19% IACS and tensile strength of 526 MPa. The study provided a new route for overcoming Fe contamination in the metal matrix, and further improving the properties of Cu alloys through various strengthening methods.
10.1016-j.matchemphys.2022.127021	4	transformation; martensite; martensitic; phase; shape; beta; memory; shape memory; temperature; temperatures; martensitic transformation; gamma; transformation temperatures; effect; thermal	Cu-rich alloys from the Cu-Al-Be, Cu-Al-Mn, and Cu-Al-Ag systems share the shape memory effect and other important properties, as well as some limitations to their application. However, the role of the atomic radius from the ternary additions on these properties remains unknown. Cu79Al19X2 (X = Be, Mn, Ag) alloys were charac-terized and compared with the Cu81Al19 alloy to evaluate which properties can be altered due to change in the atomic radius from the ternary addition. Differential thermal analysis, differential scanning calorimetry, Vickers microhardness, optical microscopy, scanning electron microscopy, energy-dispersive X-ray spectroscopy, X-ray diffraction with Rietveld refinement, resistivity measurements, and quantitative metallography were performed for this purpose. The results showed that critical temperatures and rate of melting and eutectoid phase transi-tions, the tendency for ordering, the microhardness, and the electrical resistivity from the Cu-rich solid solution are responsive to the change in atomic radius from the ternary addition. Furthermore, all ternary additions resulted in hampering of alpha phase ordering, delay of the beta phase decomposition, and decrease in the grain boundary surface. The intensity of all these phenomena can also be related to the variation of the atomic radius from the ternary addition.
10.1016-j.matchemphys.2022.127249	-1		Copper-Chromium-Zirconium alloys are popular in the field of electronic materials because of their excellent electrical conductivity and good mechanical strength . However, it is still a challenge to manufacture Cu-Cr-Zr alloy parts through additive manufacturing. In this study, Cu-Cr-Zr alloy was processed by laser powder bed fusion (LPBF) and the optimal processing parameters were determined by monitoring the sample's density. To improve the strength and electric conductivity, the samples were undergone direct aging treatment from 400 degrees C to 620 degrees C. As the aging temperature increased, the tensile strength of the alloy increased firstly and then decreased. The electrical conductivity gradually increased with the aging temperature. After aging at 475 degrees C for 2 h, the tensile strength of the alloy reached 519.3 MPa, while keeping a good elongation of 15.5% and electrical conductivity of 78.7 %IACS. The theoretical calculation showed that the precipitates of Cr-enriched phases were the main reason for the increase in strength and electrical conductivity.
10.1016-j.matchemphys.2023.127313	2	corrosion; surface; film; electrochemical; films; spectroscopy; layer; current; solution; potential; resistance; composition; x-ray; ions; showed	Pyrazine derivatives are efficient environmentally-safe chemicals for protecting metallic materials against corrosion during industrial acid cleaning. However, they have been mostly investigated for steel-based materials, which limits their versatility. Therefore, assessing their efficiency for protecting other important industrial alloys, like the Cu-Ni alloys employed in industrial heat exchangers, is also necessary. Herein, we investigated 2,3pyrazine dicarboxylic acid (PDA), singly and mixed with potassium iodide (KI), as a promising inhibitor against the corrosion of 90Cu-10Ni and 70Cu-30Ni alloys in 2% HCl. Based on short-term weight loss, electrochemical impedance spectroscopy (EIS) and potentiodynamic polarization (PDP) measurements, an optimum PDA concentration (1500 ppm) impacted average of 39% and 55% on 90Cu-10Ni and 70Cu-30Ni, respectively. These values, however, depreciated slightly after 72 h . Through cooperative synergism, the addition of 5 mM KI significantly boosted PDA efficiency to 73% (90Cu-10Ni)/92% (70Cu-30Ni) at room temperature, and 51% (90Cu-10Ni)/63% (70Cu-30Ni) at 60 degrees C. PDA is a mixed-type corrosion inhibitor with slightly more anodic impact on 70Cu-30Ni but cathodic effect on 90Cu-10Ni. This mechanism translates into more efficient surface microstructural protection for 70Cu-30Ni than 90Cu-10Ni, based on SEM characterization.
10.1016-j.matchemphys.2023.127477	14	strength; properties; conductivity; electrical; mechanical; cu-; grain; mpa; electrical conductivity; aging; precipitation; phase; mechanical properties; tensile; phases	Laser powder bed fusion was utilized to manufacture Cu-1Cr-0.19Zr alloys with varied build orientations (0 degrees and 90 degrees). The build orientation affected the grain orientation and texture of the studied alloy. Cu-1Cr-0.19Zr alloy manufactured in the 0 degrees orientation exhibited an intensive < 110 > texture. Aging the as-fabricated alloy reduced dislocations and dislocation cells and led to the formation of recrystallized grains and face-centered-cubic structured Cr precipitates (2-7 nm). The mechanical properties and conductivity of the Cu-1Cr-0.19Zr alloy increased with the aging time. The conductivity enhancement was ascribed to the decrease of defect, and im-purity scattering. Meanwhile, texture led to the anisotropy of the mechanical property in the vertical and hor-izontal planes. The optimal aging temperature and holding time were 500 degrees C and 30 min, the microhardness, electrical conductivity, and yield strength (compression) reached 220.6 HV, 62.1% IACS (International Annealed Copper Standard), and 540 MPa. The softening temperature of the peak-aged Cu-1Cr-0.19Zr alloy was 580 degrees C, which was enhanced by dispersed Cr precipitates. These findings guide to fabrication of Cu-Cr-Zr alloys by laser -assisted additive manufacturing.
10.1016-j.matchemphys.2023.127524	16	wear; composite; composites; powders; milling; particles; powder; wt; sliding; friction; hardness; matrix; mechanical; surface; properties	Copper-based Cu-1Cr-0.2Zr alloys reinforced with graphene nanosheets were fabricated via the powder metallurgy route. The alloy powders were first mechanically alloyed in a high-energy planetary ball mill up to 96 h in an argon atmosphere. Then graphene nanosheets were added (between 0 and 1 wt%) to the alloyed powder and mixed for 6 h in the milling machine. The composite powders were then consolidated in a graphite die using the spark plasma sintering (SPS) at temperatures of 650-850 degrees C under a vacuum atmosphere. Results showed that relative densities decreased with increasing graphene content but increased with the rising sintering temperature. The compressive yield stress of the composites increased with increasing the graphene content. The maximum yield stress was obtained with 1 wt% graphene, more than two-times increase compared with the parent alloy with no graphene addition. The contribution of the various strengthening mechanisms for the graphene-reinforced composites was calculated using a combined microstructure strengthening model based on the modified shear lag theory. The electrical conductivity enhanced as the sintering temperature was increased while it diminished with graphene addition. According to the results, the sintering temperature of 750 degrees C and 0.1 wt% graphene addition resulted in optimal electrical and mechanical properties.
10.1016-j.matchemphys.2023.127756	3	sma; shape; shape memory; memory; smas; superelastic; bars; damping; cu-al-mn; mechanical; bending; applications; numerical; sma bars; material	In this paper, the authors, building on the established state-of-the-art knowledge, explore the effects of thermomechanical treatments on the Shape Memory Effect (SME) and damping performance of the Cu-Al-Mn Shape Memory Alloys (SMA). Specifically, to explore the potential of application of this SMA in the form of sheets, for the purpose of designing lightweight structures with high damping performance. The casting and the thermomechanical treatment process were fully laid out in the paper. The characterization of the material in terms of chemical composition and microstructure was performed through optical microscopy and SEM coupled with EDX analysis. The temperature-induced phase transformation behavior of the alloy was explored using DSC. The damping performance was quantified through the loss factor which was measured at different levels of static tensile preload using a DMA machine. The alloy has shown significant workability which permits the fabrication of sheets. However, the material displays high sensitivity to oxidation due to a combined effect of impurities and the hot-rolling process necessary for obtaining thin SMA sheets. Nonetheless, the alloy shows competitive damping performance with respect to commercially available NiTi SMA.
10.1016-j.matchemphys.2023.127917	15	aging; strength; conductivity; electrical conductivity; electrical; mpa; treatment; strengthening; degrees; cu-; cold; precipitation; tensile strength; tensile; iacs	Designing alloys with a low resistance over a wide temperature range, specifically a low temperature coefficient of resistance (TCR), remains a great challenge from a material application perspective. In this study, the effects of Ag content and the annealing process on the microstructure, resistivity, TCR, hardness, and electrochemical corrosion properties of a Cu-7Mn-Ag-0.2Ce-0.2Zr resistance alloys were investigated. The results indicate that adding Ag to the Cu-Mn alloy can improve the solid solubility and change the lattice constant, resulting in a lower resistivity, TCR and better corrosion resistance. The hardness of the alloy increases because Ag segregates and is dispersed in the matrix to form a second phase during the annealing process. The Cu-7Mn-0.5Ag-0.2Ce-0.2Zr alloy performs the best, with a resistivity of 24.1 mu Omega center dot cm and a TCR of 76 x 10(-6)/degrees C at 300 degrees C for 1 h . The alloy had low resistivity and TCR over a wide temperature range, and it also had high stability as well as long-term performance.
10.1016-j.matchemphys.2023.128053	-1		Binary complexes that can be found in copper alloys are investigated in this work through a combination of computer simulations and machine learning. Copper alloys are made of a copper matrix and a combination of single alloying elements in n-ary forms. Due to the coexistence of different types of phases in this matrix, complex regions exist for which information on their precise atomistic structure is missing. In order to uncover such information, we apply active learning and generate moment tensor potentials. This development is based on quantum-mechanical calculations. This approach allows the on-the-fly relaxation of many thousands of potentially novel candidates and check their stability. The ground-state energy of these structures is used to build active learning-generated convex hulls, which are in turn being compared to those from the simulations and the AFLOW database. This procedure provides an insight to additional new stable copper alloy relevant binary complexes. Here, in view of Cu-Ni-Si-Cr alloys, the binary complexes Cu-Si, Ni-Si, Cr-Si, Cr-Ni, Cu- Ni, and Cu-Cr have been investigated. Their stability and the identification of novel stable candidates are discussed based on energetic arguments and the analysis of the respective phonon dispersion. The pipeline followed in this work is able to successfully predict binary phases in Cu-Ni-Si-Cr alloys, specifically for the Cu-Si, Ni-Si, Cr-Ni and Cu-Ni complexes, and to extend the already reported structures in the AFLOW library. In the end, we show the applicability of a predicted Cu-Si stable phase and the developed machine learned potentials at the larger scale of atomistic simulations for the calculation of their mechanical properties and melting behavior. This work provides a computationally efficient framework for material structure prediction and calculation of their properties at a quantum-mechanical accuracy.
10.1016-j.matchemphys.2023.128092	-1		A comprehensive understanding of the thermal stability of multicomponent bulk metallic glasses (MBMGs) is imperative for their possible technological applications. In this study, new MBMGs, Cu39Zr42Ag9Ti10 and Cu32Zr39Ag8Ti9Ni12, were developed employing a multilayer perceptron neural network, intelligently expanding the binary Cu50Zr50 BMG. X-ray diffraction (XRD) and transmission electron microscopy (TEM) analyses were used to confirm the amorphous nature of the as-cast alloys. The crystallisation kinetics of the alloys were investigated using differential scanning calorimetry (DSC) under isochronal conditions at different heating rates coupled with microstructural analyses tools. The thermal attributes suggest that glass transition and crystallisation are more sluggish in the case of Cu32Zr39Ag8Ti9Ni12 compared to Cu39Zr42Ag9Ti10. The local activation energies (E & alpha;) and the Avrami exponent (n & alpha;) indicate a diffusion-controlled crystallisation mechanism for both alloys. The nucleation rate of the crystalline phase(s) is relatively lower for Cu32Zr39Ag8Ti9Ni12, indicating sluggish crystallisation. Moreover, the rate of change of n & alpha; becomes much slower for Cu32Zr39Ag8Ti9Ni12 MBMG during the later stages of crystallisation owing to higher undercooling and, thus, a higher required driving force for the growth of nucleated phases. The free volume of Cu32Zr39Ag8Ti9Ni12 remains smaller at both room and elevated temperatures, pointing towards its better glass forming ability. XRD and TEM analyses of the crystallised alloys suggested progressively increasing precipitation of the topologically disordered Cu10Zr7 phase from Cu42Zr48Ag10 to Cu32Zr39Ag8Ti9Ni12 MBMG, potentially aiding in its increased thermal stability.
10.1016-j.matchemphys.2023.128164	15	aging; strength; conductivity; electrical conductivity; electrical; mpa; treatment; strengthening; degrees; cu-; cold; precipitation; tensile strength; tensile; iacs	Cu-Cr system alloys usually show high strength (400-600 MPa) but limited electrical conductivity (-80% IACS). In this work, a Cu-1.28Cr-0.24P (wt%) alloy with high electrical conductivity (-90% IACS) was fabricated by atmospheric melting. After homogenization, hot rolling, solid solution treatment, cold rolling, and aging treatment, the Cu-1.28Cr-0.24P alloy possessed an ultimate tensile strength of 390 MPa, yield strength of 350 MPa, and electrical conductivity of 89.4% IACS. Then continue a secondary cold rolling (50%) and aging treatment (400 degrees C, 2 h). The ultimate tensile strength, yield strength, and electrical conductivity were 380 MPa, 340 MPa, and 91.2% IACS, respectively. After aging treatment, submicron Cr3P and nano-scale Cr particles appeared in the Cu matrix, and Cr particles were the primary strengthening particles. The designed alloy achieved high electrical conductivity and considerable strength, which would become a new family member of high-electrical conductivity copper alloys.
10.1016-j.matchemphys.2023.128223	-1		The oxide dispersion strengthened (ODS)-Cu alloys produced by the combined process of mechanical alloying and hot isothermal pressing (MA-HIP) process have high strength properties, although they have low ductility. In this study, the MA-HIP process was modified based on the yttrium addition and oxygen addition methods to improve the ductility by controlling the microstructure of the ODS-Cu alloys. Namely, we replaced pure Y and Cu2O powders with a Cu-Y intermetallic compound and pre-heated Cu powders as the starting materials. The final product showed considerable microstructural differences: on the macro-scale, the frequency of interconnection of large/small Cu grain colonies, which was a main factor in brittle fracture, was reduced; while on the nanoscale, yttrium remained as yttria (Y2O3) particles within the large size Cu grains. These multiscale microstructural changes resulted in the improved mechanical property: the newly-developed ODS-Cu bulk did not fracture at bending strains of 18% or greater, which can be compared with the previous value of 5% or less in a three-point bending test. Furthermore, the conductivities of our ODS-Cu alloys are 94-96% of pure Cu. This improvement in properties, therefore sheds light to the future application of the ODS-Cu alloys in hightemperature environments.
10.1016-j.matchemphys.2023.128660	-1		This study investigates the manufacturing of copper-AA6063 aluminum alloy composite wire and the effect of microstructural changes and metal-metal interface after annealing at 300 degrees C at different times on the strength and electrical conductivity. For fabrication of the composite wire, first AA6063 aluminum alloy wire was inserted inside an OFHC copper tube with a diameter of 6 mm. Afterward, a composite wire was produced using a cold drawing process in thirteen steps to a diameter of 1.5 mm. The tensile and microhardness tests used for evaluation of the composite wire's mechanical properties. Also, the light and scanning electron microscopes (SEM) used for microstructural characterization. The results showed that forming a region with a strain gradient at interface has a determinative effect on the strength and ductility of composite wire. The composite wire without annealing showed the highest strength, 278 +/- 7 MPa. The annealing treatment result in strength reduction and negligible change in the electrical conductivity. The composite wire after annealing treatment for 30 and 60 min showed the highest electrical conductivity, 83 +/- 1%IACS, and the highest elongation, 45 +/- 4%, respectively.
10.1016-j.matchemphys.2024.129263	1	shape; memory; shape memory; damping; martensite; martensitic; damping capacity; transformation; capacity; strain; superelasticity; temperature; cu-al-mn; shape memory effect; effect	Ultra-high temperature aging was conducted on the Cu-11.9Al-2.5Mn (wt%) shape memory alloy (SMA) with the aim of damping improvement. The martensite laths were refined, and the controllable precipitation of gamma 2 phase was realized. As the aging temperature decreased or the aging time prolonged, the amount of gamma 2 particles increased. The damping of the Cu-Al-Mn SMA measured in this study belongs to non-linear damping, and the damping plateau in the martensite state mainly arises from the sliding of the martensite/martensite interfaces and the stacking faults in martensitic variants. The increased density of the martensite/martensite interfaces caused by grain refinement, the de-pinning of dislocations, and the annihilation of quenched-in vacancies after aging contributed to the increase of damping, whereas the increased density of stacking faults and the pining of gamma 2 particles on various interfaces leaded to the decrease of damping. The specimen aged at 590 degrees C for 5 min has the highest damping plateau. Its damping capacity at room temperature is 3.5 times that of the quenched specimen. The effect of aging on the tensile properties was also studied, and based on in-depth microstructural observation, correlated mechanisms were discussed.
10.1016-j.matchemphys.2024.129327	-1		Overcoming the strength-conductivity trade-off has long been an issue for commercial copper alloys. However, a synergy between strength and electrical conductivity can be achieved by reasonable adjustment of the microstructure. It is known that the formation of Short-Range Order (SRO) in a solid solution can change the mechanical and electrical behavior of the materials. Currently, the prediction of SRO formation is widely based on computational techniques. In the present study, Miedema's thermodynamical approach is applied for the assessment of alloying elements' potential to form SRO in the copper lattice. According to this methodology, magnesium tends to form SRO with copper. The mechanical, electrical, and structural properties of the oxygenfree copper (Cu-OFC), Cu-Mg0.14 wt%, and Cu-Mg0.50 wt% strips fabricated by continuous extrusion forming process (Conform) have been investigated. According to the optical microscopy investigations, the average grain sizes of the Mg alloyed samples were observed to be lower compared to that of OFC. The Vickers hardness measurements were carried out and the hardness values for Cu-OFC, Cu-Mg0.14, and Cu-Mg0.50 samples were recorded as 56.3 HV, 76.05 HV, and 87.68 HV, and the yield strengths as 80, 150 and 260 MPa, respectively. A decrement in electrical conductivity was observed with the increasing Mg addition. Dynamic elastic modulus test measurements, which refer to internal friction, have been performed by impulse excitation technique to elucidate the presence of SRO in the dilute Cu-Mg systems. The anomalous bump formation in the temperature-elastic modulus profiles of the Cu-Mg samples was remarkable which has been attributed to the SRO formation.
10.1016-j.matchemphys.2024.130006	-1		A solution-treated Cu-0.5Cr-0.05Zr-0.05Ti (wt%) alloy was drawn into a large-depth cup implementing a twostage deformation process in the present study, firstly using a & empty;50 mm cylindrical punch and subsequently redrawn by a & empty;34 mm punch . The redrawn cup wall was subjected to aging heat treatment up to 400 degrees C, 500 degrees C, and 600 degrees C for 2 h followed by water quenching to understand the microstructural evolution and its correlation with mechanical properties. These aging temperatures were adopted to simulate a similar environmental condition in which the inner liner of the thrust chamber of cryogenic and semi-cryogenic engines was exposed during satellite launching. It was identified that the above aging temperatures influenced the grain characteristics, recrystallization, and annealing twin formation significantly. The redrawn cup wall possessed semicoherent bcc spherical Cr-rich precipitates with an average size of 1.8 +/- 0.1 nm, which progressively increased to 5.5 +/- 0.3 nm at 600 degrees C, while the precipitate volume fraction increased to a maximum of 1.2% at 500 degrees C. The precipitation mostly influenced the strength, while the recrystallization and twin formation governed the ductility during the aging. After an initial decrement at 400 degrees C, the yield strength of the aged specimen was increased to a maximum of 193 MPa with a concurrent increase in ductility to 24% upon the optimal aging at 500 degrees C. However, a higher increment in the strength than the ductility indicated the dominance of the precipitation. Further increase in the temperature to 600 degrees C reduced the strength while considerably enhancing the ductility. This was attributed to the highest recrystallization and twin fraction, as well as precipitate coarsening with reduced volume fraction. Moreover, precipitation strengthening prevailed in the aged specimens, unlike dislocation strengthening in the redrawn condition. The contribution from the former was maximum at 500 degrees C with a 52% share of the total estimated strength, whereas it was only 31% in the redrawn specimen.
10.1016-j.matchemphys.2024.130183	-1		In this paper, we report the strain-controlled cyclic deformation behavior of copper-Cu50Zr50 metallic glass (MG) core-shell structures using the molecular dynamics (MD) simulation. Specimens with different MG shell thicknesses (12.5 & Aring;- 50 & Aring;) and crystalline copper core thickness (50 & Aring;) are used for the investigation. The cyclic deformations are carried out at a temperature of 300 K and strain amplitudes in the range of 0.05-0.13. With increasing MG thickness, the fatigue properties of the core-shell specimens improve. The fatigue ductility exponent is -0.45, and the fatigue strength exponent is -0.13. The deep machine learning model bidirectional long short-term memory (Bi-LSTM) is used to predict the cyclic stress-strain response of core-shell structures using the MD data. For training the model, 16,800 data points are used, comprising forty-three data sets. The model accurately predicts the cyclic behavior at all the strain amplitudes on the trained data. The R2 values are in the range of 0.947-0.998 on the test data, indicating the goodness of the fit. Hence, the model can be used to predict the fatigue behavior of materials, reducing the time required for experimentation.
10.1016-j.matchemphys.2025.130566	-1		Cu-Sn alloys primarily undergo galvanic corrosion in chlorine-containing environments. The corrosion sequence is determined by the work function. In this study, the regulatory mechanism of surface work function was investigated for the adsorption of Cl atoms on the main components of Cu-Sn alloys: Cu, Sn, Cu6Sn5, and Cu3Sn. The results indicated that, on clean surfaces, the order of the work functions for the four structures did not align with the experimentally observed sequence of galvanic corrosion. However, when the Cl atom coverage on each surface exceeded 1/2, the work functions regulated by the chlorine atoms corresponded with the results observed in experiments. Through fitting, a linear relationship between the changes in surface dipole moment and work function was established. The interactions between Cl atoms on the Sn and Cu surfaces resulted in fluctuations in the work function, while the proximity of Cl atoms to the surface on the Cu3Sn structure led to a slower variation in its work function. Consequently, under the regulation of Cl atoms, the differences in work function changes among the four structures resulted in a redistribution of the work function magnitudes. This redistribution of work functions provides new insights into the corrosion mechanism of Cu-Sn alloys and suggests potential strategies for corrosion prevention.
10.1016-j.matchemphys.2025.130739	6	grain; deformation; strain; strength; dislocation; cu-; tensile; size; ecap; grain size; sfe; ductility; hardening; high; stress	Hot compression testing was used to study how the sulfur content affects the hot deformation behavior and processing map of the deoxidized high-phosphorus copper (Cu-DHP) alloy. The results demonstrated that increasing sulfur content from 4 to 356 ppm significantly raises the flow stress. Processing maps indicated that the low-sulfur alloy exhibits a wider domain for dynamic recrystallization (DRX) with high power dissipation index values. However, the domain at low temperature range of 500-650 degrees C was absent for the high-sulfur alloy, and the flow instability domain at low temperatures and high strain rates became much wider. These observations were supported by the microstructural analysis and it was concluded that sulfur impurity has a serious adverse effect on the hot workability of pure copper. Nevertheless, the high-sulfur alloy showed a finer DRX grain size (D) at the same Zener-Hollomon parameter (Z) due to the retardation effect of sulfur. The simple formulae of D = 2738/Z0.1136 and D = 11453/Z0.1980 were proposed for the low-sulfur and high-sulfur alloys, respectively. The hardness (H) values for both alloys were consistent with the single Hall-Petch line of H = 43.38 + 175.47/ root D, formulating the effect of grain refinement on the mechanical properties. Finally, the development of the superimposed processing map and grain size map for these alloys was another major contribution of this work.
10.1016-j.matchemphys.2025.131282	-1		In this paper, the Al content ranges from 8.0 to 11.0 wt% of as-cast and as-quenched Cu-Al-Mn alloy was investigated. With the increase of Al content, the amount of the alpha phase was decreased and the amount of the (3 phase was increased. This can result in an upward trend of the phase transition temperature. The quenching treatment suppressed the eutectic reaction of the (3 phase, reduced the precipitation of the alpha phase, and the relatively high amount of Al in the (3 phase caused phase transformations of the as-quenched alloy. The quenching treatment resulted in an increase of dislocations in the alloy, making the phase transformation temperature of the as-quenched alloy much lower than that of the as-cast alloy. The increase in Al content led to an increase in the ordering of the alloy resulting in an increase in the phase transformation temperature and brittleness.
10.1016-j.matchemphys.2025.131496	-1		Immiscible alloys hold great promise for industrial and electronic applications. The complexity of liquid-phase separation and the difficulty of in situ observation often necessitate numerical simulation. However, twodimensional models cannot capture genuine three-dimensional morphology or coupled multiphysics effects. To overcome these limitations, a three-dimensional phase-field model was developed for the Cu-Co binary system, coupled with systematic undercooling experiments to investigate the dynamic evolution mechanisms of phase separation. The results show that, under the combined effects of Marangoni motion and Ostwald ripening, Cu-Co alloys with different compositions undergo distinct microstructural evolutions, eventually forming coreshell structures with a Co-rich core and a Cu-rich shell. The phase with a lower volume fraction preferentially migrates and nucleates toward the interior of the melt, while differences in surface tension determine the final morphology of the core-shell structure. The simulation results show a high degree of consistency with the experimentally processed alloys morphologies, thereby validating the model and providing a reference for threedimensional modeling of alloy microstructural evolution under coupled multiphysics conditions.
10.1016-j.matdes.2004.06.002	-1		Internal oxidation is a commercial method for producing oxide dispersion strengthened copper (ODS Cu). In this paper, the dilute Cu-Al alloy powders containing 0.26 wt% of Al have been internally oxidized at temperatures (T) from 700 to 1000 degrees C, for holding times (t) up to 10 h . The alumina particle size has been observed and determined by electron microscopy using the two-stage preshadowed carbon replica method. By the use of backpropagation network, the non-linear relationship between internal oxidation process parameters (T, t) and alumina particle size has been established on the base of dealing with the experimental data. The results show that the well-trained backpropagation neural network can predict the alumina, particle size during internal oxidation precisely and the prediction values have sufficiently mined the basic domain knowledge of internal oxidation process. Therefore, a new way, of optimizing process parameters has been provided by the authors.
10.1016-j.matdes.2006.01.030	16	wear; composite; composites; powders; milling; particles; powder; wt; sliding; friction; hardness; matrix; mechanical; surface; properties	Sintered steels find increasing application as bearings and gears due to economical and technical reasons. Materials used for making these machine elements need to have high strength, good wear resistance and low coefficient of friction. An attempt is made to develop molybdenum di sulphide added iron-copper-carbon sintered steels using simple single stage compaction and sintering elemental powders. Friction and wear characteristics of the developed materials were evaluated using cylindrical specimens in a pin-on-disc sliding apparatus. Addition of molybdenum di sulphide increases the compressibility and increases the part density. Strength and hardness of the molybdenum di sulphide added compositions are better than the base composition. Addition of the 3% molybdenum di sulphide is found to be beneficial in improving friction and wear characteristics. Higher amount of brittle phases in the 5% molybdenum di sulphide added sample contributes to the reduction in the wear resistance. (c) 2006 Published by Elsevier Ltd.
10.1016-j.matdes.2007.07.003	16	wear; composite; composites; powders; milling; particles; powder; wt; sliding; friction; hardness; matrix; mechanical; surface; properties	This paper aims to study effect of compaction pressure on properties and spot welding behaviour of Cu-10 wt%Al2O3 composite prepared via two powder mixing methods, i.e. ball milling and mechanical alloying. The composite is either mixed in a low energy ball mill or by mechanical alloying in a high energy planetary mill for 45 min. The mixture was then compacted at 100, 200, 300 and 400 MPa and sintered in argon atmosphere at 950 degrees C for 1 h . Results showed that composite prepared via mechanical alloying has better hardness and lower electrical conductivity and density than its counterpart due to powder refinement. Higher compaction pressure increases the hardness, electrical conductivity and density of the composite prepared by both methods. The mechanical alloyed composite compacted at higher pressure imparts material flow during spot welding operation. Thus, spot weld with higher strength was obtained.
10.1016-j.matdes.2008.04.055	16	wear; composite; composites; powders; milling; particles; powder; wt; sliding; friction; hardness; matrix; mechanical; surface; properties	Metal matrix composites containing dispersion of hard ceramic particles in a ductile matrix are increasingly used for automotive, aerospace and structural applications. There is a need to generate data on wear performance of Cu-SiCp composites, which is directly useful as design parameter. This paper reports the modeling of dry sliding wear behaviour of Cu-SiCp (10-40%) composites. SiC particles were pre-coated with copper by a three-step electroless deposition technique. Copper matrix composites reinforced with 10%, 20%, 30% and 40% SiCp were made by powder metallurgy route. The compression test data was used to determine stress-strain relationship and relevant mechanical properties of Cu-SiCp composites. Dry sliding wear tests of Cu-SiCp composites were carried out using pin on disc apparatus with a typical experimental plan of simultaneous variation of load and sliding speed in the selected range. Experimental response data were analyzed by dimensional analysis method. An experimental model is proposed for Cu-SiCp composites; (Z)n = K-2(1/Xy)(K1), illustrating an important difference in sliding wear behaviour of single phase Cu base alloys and Cu-SiCp composites. The differential form of final dimensional equation gives comparative evaluation of dimensional constants K-1 and K-2 with Archards constant. The dimensional constants K, and K2 determined in this study can be used to evaluate wear performance of Cu-SiCP composites. The limitations of the model relevant to tribological properties of the composites are presented.
10.1016-j.matdes.2008.06.068	16	wear; composite; composites; powders; milling; particles; powder; wt; sliding; friction; hardness; matrix; mechanical; surface; properties	Fabrication of tungsten-copper net-shapes has become an important issue in recent years due to their unique properties which make them suitable for a wide variety of applications. In this investigation, W-Cu composite powders containing 20 wt% and 30 wt% Cu were processed by powder metallurgy technique using two types of prepared powders, namely, Cu-coated tungsten and mixtures of elemental powders. The coating method of tungsten powders was carried out using electroless coating technique. The investigated powders were cold compacted and sintered in vacuum at two sintering temperatures, 1250 degrees C and 1400 degrees C. The results show that the Cu-coated compacts have higher relative green densities than those of admixed ones for each copper content and compaction pressure, which means that the coated powders have greater compressibility than the uncoated ones. The relative green density increases with increasing compaction pressure and copper content. After sintering, the composites fabricated from uncoated powders show inhomogeneous structure due to formation of large globules of copper and tungsten agglomerates, while the structure of coated tungsten composites reveals the existence of copper within the tungsten grains, forming uniform interconnected structure. In general, composites made from Cu-coated tungsten powders exhibited higher density, hardness, compression strength, and electrical conductivity than those of composites made from admixed elemental powders. However, coefficient of thermal expansion and electrical resistivity of Cu-coated composites showed lower values.
10.1016-j.matdes.2009.04.017	-1		The Cu-10Cr-0.4Zr alloy and the in situ composites based on the alloy were prepared. Microstructure evolution and mechanical properties of Cu-10Cr-0.4Zr in situ composites were investigated. The results showed that the addition of 0.4 wt% Zr in the Cu-10 wt% Cr in situ composites gave birth to smaller ascast Cr dendrites, which led to finer filaments at higher strain ratios. The ultimate strength of Cu-10Cr0.4Zr composites reached 1089 MPa at draw ratio of eta = 6.2. however that of Cu-10Cr prepared by the same procedure was only 887 MPa. The increasing strength of Cu-10Cr-0.4Zr in situ composites could be attributed to the combination of Hall-Petch strengthening of closely spaced Cr filaments, the strengthening effect of Zr and the strengthened Cu matrix. Crown Copyright
10.1016-j.matdes.2010.12.036	5	materials; thermal; heat; properties; material; welding; sintering; fusion; strength; laser; heat sink; thermal conductivity; mechanical; sink; manufacturing	As the material and manufacturing cost of coins approached or even exceeded the face value of coins over the last 10 years, the needs to develop less-expensive alloys to replace the current coinage materials increased. The objective of this study is to develop new cost-effective alloys with the same vending machine acceptability and similar color tone as Cu-25%Ni coins. Cu-Zn-Ni-Fe and Cu-Zn-Ni-Fe-Cr alloys developed in this study were found to have the electrical conductivity close to and color similar to that of Cu-25Ni. The strengths of the annealed Cu-25.5%Zn-12%Ni-1.5%Fe and Cu-25.5%Zn-12%Ni-1.5%Fe-0.28%Cr alloys were observed to be 451 MPa and 512 MPa, respectively, with excellent ductility, suggesting that these alloys could be substitutive to Cu-25%Ni alloy for other general structural applications as well as coinage application. Both alloys exhibited the typical ductile fracture surfaces. Cu-Zn-Ni-Fe alloy was found to be a better candidate for coins because of the better formability and machinability associated with its moderate strength and excellent ductility.
10.1016-j.matdes.2011.01.015	-1		In this study, the effect of various feed speeds on microstructure and mechanical properties of friction stir welded Cu-30Zn brass alloy is investigated. Rotation speed was fixed at 950 rpm and feed speed varied in the range of 190-375 mm/min. Examination of the microstructure showed very fine grains with some deformed grains in the stirred zone and some coarser grains in the thermo-mechanically affected zone and base metal. A unique deformation pattern, namely stir band in the stirred zone region was identified and its density increased by increase in feed speed. Results showed that the grain size profile was independent of feed speed and the hardness values decreased by increase in feed speed. Increase in feed speed led to a slight improvement of yield strength and ultimate tensile strength, associated to continuous spring-like morphology of stir bands acting as a strengthening structure. However, ductility reduces considerably from 57 to 27%. Moreover, it is observed that during tensile test, fracture cracks originate exactly adjacent to the stir bands.
10.1016-j.matdes.2011.03.042	-1		Cu-Al2O3 nano-composite coatings have high potential for use in applications in which high mechanical properties together with high corrosion resistance are required. In the present study it is intended to produce copper nano-alumina composite coatings with various nano-alumina contents in order to investigate the effect of alumina reinforcement particles on corrosion resistance and mechanical properties such as hardness and wear resistance. The composite coatings were deposited using direct current (DC) and pulse current (PC) plating. The microstructures of the coatings produced from both methods were examined via scanning electron microscopy (SEM) and X-ray diffraction (XRD) techniques. The wear behaviors, micro hardness, coating thickness, corrosion rate and coating porosity were examined using appropriate methods. Compared to DC deposition, PC plating facilitated higher amounts of particle incorporation with more uniform distribution. The results indicated that the mechanical properties of the applied coatings with incorporated nano-alumina reinforcement were far more superior as compared to its own matrix as well as non-composite copper coatings. It was also found out that increasing the amount of nano-alumina content in the coating, led to enhanced general properties of the coatings.
10.1016-j.matdes.2011.06.006	-1		W(f)/Cu(82)Al(10)Fe(4)Ni(4) composite was fabricated by flow casting method. Dynamic compression tests with strain rate of 1600 s(-1) at 20 degrees C, 200 degrees C, 400 degrees C and 600 degrees C were finished by means of Split Hopkinson Pressure Bar (SHPB). The results showed that the composites possessed obvious high temperature softening behaviors. The damages of W(f)/Cu(82)Al(10)Fe(4)Ni(4) composites all occurred within the tungsten fibers when compressed at 20 degrees C, 200 degrees C and 400 degrees C, indicating that the interface strength of the composites was high . While the damages of the composites occurred either in the tungsten fibers or in the matrix at 600 degrees C. in addition, the melt of matrix alloy also occurred. Microstructure of the composites after dynamic compressing at 600 degrees C was analyzed by transmission electron microscope (TEM), observation revealed that there were a lot of high-density dislocations, stacking faults and twins existing in the matrix. It was also found that the precipitated phase in the matrix played the role of the second phase strengthening.
10.1016-j.matdes.2011.10.021	16	wear; composite; composites; powders; milling; particles; powder; wt; sliding; friction; hardness; matrix; mechanical; surface; properties	Thermo-chemical technique was used to synthesize Cu-Al2O3 nanocomposite powders. The process was carried out by addition of Cu to aqueous solution of aluminum nitrate. Afterwards, a thermal treatment, or firing process was conducted to get the powders of CuO and Al2O3 and remove the remaining liquid. The CuO was then reduced in preferential hydrogen atmosphere into copper. The nanocomposite powders were cold pressed into briquettes and sintered in hydrogen atmosphere. The structure and characteristics were examined by X-ray diffraction (XRD), scanning electron microscopy (SEM) with energy dispersive spectrometer (EDS) and transmission electron microscopy (TEM) and metallography techniques. The compression, density, hardness and wear behavior of Cu-Al2O3 nanocomposite were investigated. The results showed that alumina particles of 30 nm. The metallography showed that the alumina nanoparticles were fairly dispersed within the copper matrix. The structure revealed the formation of third phase (CuAlO2) at copper-alumina interface. The results also showed great improvement of compression strengths, hardness and wear resistance by increasing alumina contents. However, increasing alumina contents decreased density. Compressive properties of the nanocomposite showed dependent values on strain rates, as strain rates are increased, strength of nanocomposite increased. The wear rates of the nanocomposites increased with increasing applied loads or sliding speed. The wear rate of the monolithic copper is more than that of the nanocomposites.
10.1016-j.matdes.2012.04.048	6	grain; deformation; strain; strength; dislocation; cu-; tensile; size; ecap; grain size; sfe; ductility; hardening; high; stress	In this study, variations of hardness, electrical conductivity, strength, elongation and microstructure of the Cu-13.5%Mn-4%Ni-1.2% Ti alloy were investigated during aging, cold-working and subsequent aging. X-ray diffraction (XRD), transmission electron microscopy and scanning electron microscopy methods were used to evaluate the microstructure of the alloy. Tensile, hardness and electrical conductivity measurements were also used for investigating the effects of processing parameters on the characteristic of the alloy. Hardness value of 190 HV and strength of 644 MPa were obtained after aging the as-cast alloy for 4 h at the temperature of 500 degrees C. The maximum hardness and strength increased up to 253 HV and 816 MPa, respectively, after aging 60% cold-worked samples for 1 h at the temperature of 500 degrees C. The dominant strengthening mechanism during aging was attributed to the precipitation of Cu4Ti phase. Formation of the beta-Cu3Ti phase during aging at the temperature of 500 degrees C was another reason of strengthening. As a result of aging, electrical conductivity of both as-cast and cold-worked alloys was improved. The maximum conductivity of 29.7% IACS was attained after aging the as-cast material at the temperature of 500 degrees C for 4 h .
10.1016-j.matdes.2012.06.041	16	wear; composite; composites; powders; milling; particles; powder; wt; sliding; friction; hardness; matrix; mechanical; surface; properties	Studies have been carried out on the effect of hot rolling on the enhancement of mechanical properties of sintered low density Cu-8 at% Cr-4 at% Nb alloy made from gas-atomised powders by vacuum hot pressing using varying pressure and temperature. The pressure is varied from 10 to 30 MPa whereas, 800, 900 and 1000 degrees C are three hot-pressed temperatures. Though hot rolling of porous low density hot-pressed samples results in near theoretical density, the hot-pressed sintered material with higher initial porosity shows lower strength and ductility after rolling. Hot-pressed compacts below certain density could not be rolled and the sample has cracked during rolling. The higher density material could be easily rolled and significant improvement in mechanical properties has been noticed. This has been attributed to the conversion of porosities into microscopic cracks which could not be healed due to the presence of Cr2Nb precipitates. Finally, structure property correlation has been established.
10.1016-j.matdes.2012.08.073	16	wear; composite; composites; powders; milling; particles; powder; wt; sliding; friction; hardness; matrix; mechanical; surface; properties	The effects of high-frequency ultrasonic peening (HFUP) on the tribological characteristics of Cu-based materials sintered on low carbon steel by a powder metallurgy (P/M) technique were investigated. The friction and wear properties of the Cu-based materials were studied using a pin-on-disk reciprocating tribotester sliding against a hardened steel ball under dry and oil-lubricated conditions. Scanning electron microscopy (SEM) was utilized to analyze the worn surfaces and to assess the wear mechanisms. Experimental results showed that the HFUP process led to a reduction in friction and wear of the Cu-based materials in both dry and oil-lubricated conditions. This was attributed to the increase in hardness of the HFUP treated specimen. It was also found that the friction coefficient was independent of the normal load but decreased with increasing sliding speed. In addition, inclusion of Fe in the Cu-based material was helpful in reduction of friction and wear. SEM analyses showed that abrasive wear was the dominant wear mechanism of the specimens. The results of this work demonstrate the effectiveness of HFUP in improving the tribological properties of Cu-based materials. Crown Copyright
10.1016-j.matdes.2012.09.034	16	wear; composite; composites; powders; milling; particles; powder; wt; sliding; friction; hardness; matrix; mechanical; surface; properties	In this work, nearly full density W-23.5 wt% Cu composite was fabricated by activated sintering with Zn additive. Because of low melting point and high saturated vapor pressure for Zn, Zn additive was introduced into W-23.5 wt% Cu composite to enhance the densification of W-Cu composite. The effects of relative density, Zn additive contents, microstructure and fractographs on thermal conductivity, electrical conductivity and coefficient of thermal expansion were evaluated by scanning electron micrograph, energy disperse spectrum, X-ray photoelectron spectroscopy and Archimedes method. It was found that adding Zn additive led high relative density for W-Cu composite while thermal conductivity and electrical conductivity were preserved at good values which were 198.5 W m(-1) K-1 and 1.44 x 10(6) (Omega m)(-1), respectively. The fractographs of W-Cu composite indicated the presence of strong grain-boundaries, which was beneficial to the thermal conductivity and electrical conductivity. The coefficient of thermal expansion was decreased to appropriate value from 9.58 x 10(-6) to 8.75 x 10(-6) K-1 by controlling Zn additive content.
10.1016-j.matdes.2013.05.001	8	hot; deformation; strain; strain rate; dynamic; hot deformation; recrystallization; dynamic recrystallization; flow; rate; flow stress; compression; constitutive; degrees; stress	Hot working behavior of a novel super high strength Cu-6.0Ni-1.0Si-0.5Al-0.15 Mg-0.1Cr alloy has been studied systematically. Experiment of hot compression deformation with temperature ranging from 750 degrees C to 900 degrees C and strain rate from 0.001 s(-1) to 1 s(-1) indicated that both strain rate and deforming temperature affect the flow stress. Flow stress increased to a peak value, and then decreased with increase of deformation time, showing continuous dynamic recrystallization behavior. In the deformation temperature zone of 750-800 degrees C, nucleation of the recrystallization grains occurred in the interior grains at special locations such as deformation bands and shear bands. At the high temperature zone (850-900 degrees C), nucleation of the recrystallization grains occurred both at the grain boundaries and inside the grains of the matrix. Three typical textures appeared after hot compressive deformation and the order of the texture intensity from largest to smallest was: Copper texture of {112}< 111 >, S texture of {123}< 634 >, Gauss texture of {011}< 100 >. On the basis of established processing map, appropriate hot working temperature range was 850-875 degrees C. With the optimised hot working parameters and appropriate thermal mechanical treatment, the designed alloy has achieved excellent properties: hardness 341 HV, tensile strength 1090 MPa, yield strength 940 MPa, elongation 3.5%, electrical conductivity 26.5% IACS, and the stress relaxation rate 8.52% as tested at 150 degrees C for 100 h .
10.1016-j.matdes.2013.05.029	6	grain; deformation; strain; strength; dislocation; cu-; tensile; size; ecap; grain size; sfe; ductility; hardening; high; stress	The pure Cu rods with an initial grain size of 410 mu m were treated by using equal channel angular pressing (ECAP). The deformed microstructure and mechanical properties of ECAPed Cu samples were investigated. Special attention was paid on the refinement of grain size and local micromechanics of ECAPed Cu samples. The original coarse grains were refined to 320 mu m after 4 passes. The final grains were composed of dislocation cells with a size of 500 nm-3 mu m after 5-8 passes. The yield strength reached a saturation value of 368 MPa after 5 passes. The maps of microhardness distribution illustrated the inhomogeneity of local mechanical properties. The dislocation subdivision was the main deformation mode to refine the grain size, while twin fragmentation was restrained by dislocation slips for the reason of large initial grain size. Furthermore, the strengthening of ECAPed Cu was discussed.
10.1016-j.matdes.2013.11.070	16	wear; composite; composites; powders; milling; particles; powder; wt; sliding; friction; hardness; matrix; mechanical; surface; properties	The present work includes the effect of W addition in improving the properties of Cu with the help of high-energy mechanical alloying. Composite preforms of (5-15 W) with copper were fabricated by Powder Metallurgy (P/M) method. The preforms were sintered at 850 degrees C, subsequently the furnace was cooled and again the specimens were hot extruded to get 92% preform density. Four point probe tester, Scanning Electron Microscope, Energy Dispersive Spectrum and pin on-disc system were used to evaluate electrical conductivity, characterization and tribological property of Cu-W composite respectively. The various stages in dominant oxidation and delamination wear mechanism was clearly discussed. The wear rate and coefficient of friction decreased with increase in load and sliding distance. Design expert software was used to develop contour map, mathematical model and useful conclusions were made.
10.1016-j.matdes.2014.04.012	16	wear; composite; composites; powders; milling; particles; powder; wt; sliding; friction; hardness; matrix; mechanical; surface; properties	The current study aims to show for the first time the ability of friction stir processing (FSP) in incorporating yttria particles into copper to produce an oxide dispersion strengthened material. The microstructure of the as-developed composites was characterized at various scales by light microscopy, electron probe microanalysis (EPMA) and scanning and transmission electron microscopy. The powder was found to be distributed in the Cu matrix as confirmed at various length scales from the micrometric to the nanometric level. The increase of the number of FSP passes leads to a more homogeneous and finer distribution of the particles as it favored the dissociation of the clusters of initial powder particles and the intergranular fracture of individual elemental particles. Transmission electron microscopy observations reveal that the constitutive crystallites of the initial powder, typically 10 nm in size, are frequently dissociated and dispersed into the copper matrix. In spite of their very low volume fraction, these 10 nm sized fragments which present the highest density among the various size classes of particles, exert a strengthening and work hardening effect.
10.1016-j.matdes.2014.04.070	13	clusters; atomic; glass; atoms; composition; dynamics; metallic; icosahedral; glasses; simulations; molecular; cu-zr; molecular dynamics; metallic glasses; structural	In this paper, a new equation was rationally generalized from the reduced glass transition temperature. This equation indicates that solidification range can be used for describing glass-forming ability, which can be calculated with the aid of computational thermodynamic approach . Based on this scenario, several new Cu-based bulk metallic glasses in the ternary Cu-Zr-Ti alloy system were discovered. The as-cast samples were characterized by X-ray diffraction and transmission electronic microscopy. The results indicate that as-cast samples have monolithic amorphous nature. Thermal analysis validates that the smaller solidification range is closely related to the higher glass-forming ability, which is contributed to the effect of solidification time on the formation of bulk metallic glasses. This work also suggests that solidus can influence glass formation.
10.1016-j.matdes.2014.05.068	-1		Thermal conductivity of SiCp/Cu composites was usually far below the expectation, which is usually attributed to the low real thermal conductivity of matrix. In the present work, highly pure Cu matrix composites reinforced with acid washed SiC particles were prepared by the pressure infiltration method. The interfacial microstructure of SiCp/Cu composites was characterized by layered interfacial products, including un-reacted SiC particles, a Cu-Si layer, a polycrystalline C layer and Cu-Si matrix. However, no Cu3Si was found in the present work, which is evidence for the hypothesis that the formation of Cu3Si phase in SiC/Cu system might be related to the alloying elements in Cu matrix and residual Si in SiC particles. The thermal conductivity of SiCp/Cu composites was slightly increased with the particle size from 69.9 to 78.6 W/(m K). Due to high density defects, the real thermal conductivity of Cu matrix calculated by H-J model was only about 70 W/(m K). The significant decrease in thermal conductivity of Cu matrix is an important factor for the low thermal conductivity of SiCp/Cu composites. However, even considered the significant decrease of thermal conductivity of Cu matrix, theoretical values of SiCp/Cu composites calculated by H-J model were still higher than the experimental results. Therefore, an ideal particle was introduced in the present work to evaluate the effect of interfacial thermal resistance. The reverse-deduced effective thermal conductivities of ideal particles according to H-J model was about 80 W/(m K). Therefore, severe interfacial reaction in SiCp/Cu composites also leads to the low thermal conductivity of SiCp/Cu composites.
10.1016-j.matdes.2014.09.002	17	wear; composites; coating; friction; composite; coatings; surface; tribological; properties; wear resistance; resistance; powder; sliding; matrix; wear rate	In order to obtain high porosity and satisfactory strength simultaneously for the porous metallic layer of the grinding tools, alumina bubble particles were added into Cu-Sn-Ti alloy powders to fabricate porous metals using a vacuum sintering method. The influence of the alumina bubble particles on the microstructure and the mechanical strength of the porous Cu-Sn-Ti metal blocks were investigated. Results show that adding alumina bubble particles into Cu-Sn-Ti alloy powder generate closed pore structures for the metal blocks. Good bonding interface between alumina bubble particles and Cu-Sn-Ti alloy is formed mainly dependent on the chemical resultants of TiAl and TiO. A relationship between the bending strength of the porous Cu-Sn-Ti metal blocks and the size and volume fraction of the alumina bubble particles is established.
10.1016-j.matdes.2014.09.025	-1		In situ TiB2 particulate reinforced copper matrix composites were prepared using Cu-Ti and Cu-B master alloys. Rotating magnetic field (RMF) was employed to improve the dispersion of in situ TiB2 particles during casting. The influences of RMF on the microstructures, TiB2 distribution and mechanical properties of thus prepared composites were investigated. The results show an improved distribution of TiB2 particles in the copper matrix, which resulted in the improvement of mechanical properties of Cu/TiB2 composites. The ultimate tensile strength and Vickers hardness of Cu-1 wt% TiB2 with a 30% reduction hot rolling and a 90% reduction cool rolling increased from 405 MPa, 125 HV to 470 MPa, 171 HV by the variation of field currents, respectively. Moreover, the action mechanism of RMF on TiB2 distribution in the copper matrix was explained and analyzed.
10.1016-j.matdes.2014.11.005	-1		Mechanical performances and fracture behavior of serial-type and parallel-type Cu-Ni-Zn/Cu-Cr composites prepared by diffusion bonding were investigated. One advantage of Cu-Ni-Zn/Cu-Cr joining is the good bondability with no detrimental interfacial compounds. The conductivity of Cu-Ni-Zn/Cu-Cr composites reached 59-63% IACS (International Annealed Copper Standard) with aging. In the serial-type Cu-Ni-Zn/Cu-Cr composite (with the loading axis perpendicular to the interface), deformation is concentrated in the weaker side of the two joined alloys and no interface fracture occurred at a stress as high as 290 MPa if the strength difference is appreciable. Interfacial fracture occurred in the serial-type composite as the strain is concentrated and the slip incompatibility developed near-interface region when the strengths of two alloys become comparable by aging. In the aged parallel-type Cu-Ni-Zn/Cu-Cr composite (with the loading axis parallel to the interface), strain accommodation across the interface was difficult because of the high strength of aged Cu-Cr and interface debonding occurred as the lateral stress developed across the interface with strain. Strain concentration and strain incompatibility at the interface is the necessary requirement for interface fracture of composite.
10.1016-j.matdes.2014.12.034	4	transformation; martensite; martensitic; phase; shape; beta; memory; shape memory; temperature; temperatures; martensitic transformation; gamma; transformation temperatures; effect; thermal	The influence of microstructural parameters on damping capacity in beta CuAlBe polycrystalline shape memory alloys was studied in detail by compression tests. For higher maximum stresses, the pseudoelastic strain increases, higher values of dissipated energy are obtained, and the specific damping capacity increases to reach a stable value. As the grain size of the samples increases, the dissipated energy decreases, but higher values of the specific damping capacity are obtained and at lower strains. A similar behavior is observed as the test temperature decreases in the range of 278-340 K. Stress-grain size and stress-temperature diagrams were constructed, indicating the areas where it is possible to obtain the PE effect, and the optimal working zones. A quantification of the dissipated energy and the specific damping capacity as a function of sigma(max), grain size, and temperature was realized.
10.1016-j.matdes.2015.02.017	0	solidification; phase; magnetic; magnetic field; undercooling; field; liquid; separation; peritectic; immiscible; cu-; dendrite; phase separation; microstructure; primary	The dynamic solidification of peritectic Cu-70% Sn alloy was accomplished within a 20 kHz ultrasonic field under the power range up to 440 W. The ultrasound promotes the nucleation of primary epsilon(Cu3Sn) phase and prevents the bulk undercooling of liquid alloy. As sound power increases, the ultrasonic field brings about a striking size refinement effect to the primary epsilon intermetallic compound by more than one order of magnitude. Meanwhile, it facilitates or even completes the usual peritectic transformation (L + epsilon -> eta) which occurs only to a very limited extent during static solidification. This is mainly because the refinement of primary e phase induced by ultrasound greatly reduces the characteristic length of peritectic microstructure, which increases solid state Fourier number by more than one order of magnitude. The dramatic increase in the volume fraction of peritectic phase and the prominent grain refinement effect due to ultrasound lead to the remarkable improvement of mechanical properties for Cu-70% Sn alloy, whose compressive strength and microhardness are increased by factors of 4.8 and 1.45, respectively.
10.1016-j.matdes.2015.05.023	6	grain; deformation; strain; strength; dislocation; cu-; tensile; size; ecap; grain size; sfe; ductility; hardening; high; stress	The conventional high strain rate forming usually induces the occurrence of deformation twins in face-centered-cubic metals such as copper with medium stacking fault energy. In order to investigate the possible mechanical twinning of copper under a new type of high speed processing technique-elec tromagnetic forming, the pure copper was electromagnetically bulged followed by microstructural characterization through electron backscattered diffraction and transmission electron microscopy. The results revealed a reduction of twin boundaries with increasing plastic strain, indicates a non-twinning deformation mechanism which is different from the deformation twinning observed in other high speed forming process. The physical origin of the present phenomenon is discussed in detail according to the energy barrier and the critical shear stress that are required for the nucleation of perfect and partial dislocations that determine the formation of twins.
10.1016-j.matdes.2015.05.066	13	clusters; atomic; glass; atoms; composition; dynamics; metallic; icosahedral; glasses; simulations; molecular; cu-zr; molecular dynamics; metallic glasses; structural	The electronic structure of Cu100-xZrx (x = 40,50,60) metallic glasses was investigated by ultraviolet photoelectron spectroscopy and X-ray photoemission spectroscopy, the valence band spectra of these alloys were analyzed by a large shift of the Cu d-band peaks to higher binding energies upon increasing Cu content. Photoemission experiments and first-principles calculations prove that the values of density of states at Fermi level of Cu100-xZrx metallic glasses are mainly dominated by Zr rather than Cu. This work will enlighten further research on understanding the inheritance of metallic glasses and designing new metallic glasses with unique properties.
10.1016-j.matdes.2015.06.064	-1		In this paper, the microstructure and hardness evolutions of commercially pure Cu subjected to high energy mechanical milling and subsequent annealing treatments in the temperature range of 400-700 degrees C are investigated. The results demonstrated the simultaneous occurrence of recovery, recrystallization, and grain growth during annealing of the nanocrystalline Cu. The volume fraction of the recrystallized grains estimated using the grain orientation spread exhibits lower values as a result of its dynamic recovery at higher temperatures. The normal grain growth in the range of 400-600 degrees C and significant abnormal grain growth at higher temperatures are observed during annealing. As a result of the abnormal grain growth, the microhardness value rapidly decreases for the sample annealed at 700 degrees C. An analysis of the grain growth kinetics using the parabolic equation in the temperature range of 400-600 degrees C reveals a time exponent of n approximate to 2.7 and an activation energy of 72.93 kJ/mol. The calculated activation energy for the grain growth in the nanocrystalline Cu is slightly less than the activation energy required for the lattice diffusion. This low activation energy results from the high microstrain as well as the Zener-pinning mechanism that arises from the finely dispersed impurities drag effect.
10.1016-j.matdes.2015.06.146	6	grain; deformation; strain; strength; dislocation; cu-; tensile; size; ecap; grain size; sfe; ductility; hardening; high; stress	The effect of cryogenic temperature and change of strain path on grain refinement during the rolling of Cu-30Zn brass was determined. To this end, the material was unidirectionally rolled or cross-rolled to 90% thickness reduction at either ambient or liquid-nitrogen temperatures, and the resulting grain structures and crystallographic textures were determined via electron backscatter diffraction (EBSD) technique. In all cases, grain refinement was found to be governed primarily by twinning and shear banding. Lowering of the rolling temperature to the cryogenic range was found to provide only a minor effect. Cryogenic rolling was thus concluded to impart no practical benefit with regard to grain refinement or property improvement for this material. In contrast, a change of strain path via cross rolling was shown to enhance twinning and shear banding and thus to promote the formation of a relatively homogeneous ultrafine-grain microstructure.
10.1016-j.matdes.2015.10.125	-1		This paper presents the first study on welding of Cu-based shape memory alloys. The superelastic wires used in the investigation had a nominal composition of Cu-17Al-11.4Mn (at%). The pulsed Nd: YAG spot welding process altered the original bamboo-likemicrostructure of the base metal to a fusion zonewith fine equiaxed grains. Micro-load-indentation depth analysis revealed that the grain refinement increased the ductility of the fusion zone compared to the base material. Tensile tests did not show any significant difference between base material andwelded specimens, with failure occurring far away from thewelds in the larger grained base metal. Mechanical cycling and superelastic behavior of thewelded joints showed a faster stabilization of the hysteretic response than the base material, which is beneficial for applications where energy absorption is required. The Cu-Al-Mn superelastic alloy had a very high weldability and superior properties compared to other laser welded shape memory alloys, such as NiTi.
10.1016-j.matdes.2015.10.157	6	grain; deformation; strain; strength; dislocation; cu-; tensile; size; ecap; grain size; sfe; ductility; hardening; high; stress	The influences of pre-torsion deformation on microstructure and tensile strength of commercial as-extruded Cu rods with cylindrical shape have been investigated in this study by twisting the rods to different numbers of revolutions. The results indicated that the pre-torsion can significantly enhance the tensile yield strength of the as-extruded Cu rods without changing their shape and size. The increase in tensile yield strength is mainly due to the gradient lamellar dislocation substructures (LDS) embedded in elongated fiber grains introduced by pre-torsion pure shear deformation.
10.1016-j.matdes.2015.11.083	0	solidification; phase; magnetic; magnetic field; undercooling; field; liquid; separation; peritectic; immiscible; cu-; dendrite; phase separation; microstructure; primary	A sudden columnar-to-equiaxed transition (CET) of cast copper with rare earth (RE) microalloying has been examined. Some solidification parameters of Cu-La alloys were determined by using optical microscopy and differential scanning calorimetry, and simulation of temperature field in copper ingot solidification process. It is noted that the addition of RE microalloying can purify the alloy and make an interaction between equiaxed nucleation and constitutional undercooling, which results in a sudden CET. Furthermore, a new prediction model of the critical alloy composition condition for the CET induced by RE microalloying is established. The critical compositions of a sudden CET of cast copper with La addition is 0.14 wt%, which is in good agreement with the experimental results. It is suggested that increasing the alloy content is very necessary at a high gradient in order to promote the CET. However, the number N-0 of effective nucleation sites should also be increased with the decrease of the alloy composition. Meanwhile, it can be found that the columnar region can be expanded with the increase of the temperature gradient. It is obvious that lowering temperature gradient contributes to promote the CET. The prediction model can also be used in the common CET very well.
10.1016-j.matdes.2015.12.030	4	transformation; martensite; martensitic; phase; shape; beta; memory; shape memory; temperature; temperatures; martensitic transformation; gamma; transformation temperatures; effect; thermal	The structural changes of a Cu-12 wt% Ni-17 wt% Zn-1.7 wt% Al alloy as a function of the aging temperature have been studied by means of Differential Scanning Calorimetry (DSC), high resolution transmission electron microscopy (HRTEM) and hardness measurements. It has been proposed a hardening mechanism that implies the crystallization of a Ll(0) Cu2NiZn phase coherent with the matrix a phase followed, firstly, by its transformation into a Ll(2) coherent phase and, secondly, by the precipitation of this phase. It has been shown that aluminum play an important role in the precipitation hardening process because Cu2NiZn precipitates are not formed by aging a ternary Cu-Ni-Zn alloy of similar composition. It has been shown by the first time that DSC could be a powerful tool for discriminating the whole set of phase transformations undergone by alloys as a function of the annealing temperature from a single heating run.
10.1016-j.matdes.2016.03.095	6	grain; deformation; strain; strength; dislocation; cu-; tensile; size; ecap; grain size; sfe; ductility; hardening; high; stress	Cu-2% Al and Cu-4.5% Al alloys were developed by metal mould casting followed by homogenization at 800 degrees C for cryorolling. The homogenized samples were cryorolled (CR) up to the maximum possible reduction in area (similar to 75%). Activation energy for recrystallization of the CR samples was estimated by isoconversion methods using differential scanning calorimetry data; whereas, stored strain energy was determined by X-ray diffraction analysis. The activation energy for recrystallization correlated well with the stored energy of the corresponding sample. Microstructural evolution was analyzed by optical and transmission electron microscopy. The CR + annealed (225 degrees C) sample showed an improved yield strength (YS) of 810 MPa with a reasonable ductility of 5.1% The YS found to be 10 times higher than that of the cast + homogenized sample (76 MPa). This is attributed to the recovery of low angle grain boundaries, increasing grain boundary spacing, formation of nanotwins and decrease in the dislocation density without any recrystallization. The YS obtained by analytical modeling of the active strengthening mechanisms is highly corroborated with the experimental YS of the annealed sample. The Hall-Petch strengthening and dislocation strengthening found to play the pivotal role in the improvement of mechanical properties.
10.1016-j.matdes.2016.05.081	-1		In this work, the dynamic behavior of nanostructured Cu-11.14% Al alloy with face-centered cubic (FCC) structure has been investigated using split Hopkinson pressure bar. At high strain rate uniaxial compression (strain rate similar to 4 x 10(3) s(-1)), a sharp stress collapse was observed in the plastic regime of the specimens. Post-loading examinations verified the appearance of adiabatic shear band (ASB), which has rarely been observed in FCC metals under uniaxial loading. Adiabatic heating within the ASBs has led to recrystallization, resulting in remarkably refined and defect-free nanocrystalline grains. The occurrence of ASBs in such an FCC alloy can be explained based on established mechanistic models.
10.1016-j.matdes.2016.05.084	6	grain; deformation; strain; strength; dislocation; cu-; tensile; size; ecap; grain size; sfe; ductility; hardening; high; stress	In this paper, we report themicrostructure evolutions of symmetrically and asymmetrically rolled Cu at different temperatures, and reveal an important role of asymmetry induced microstructure homogeneity and removal of local severely distorted structures on the enhancement of thermal stability. With the sametotal reduction of 90%, two kinds of submicron grained (SMG) Cuwere processed by symmetrical and asymmetrical rolling respectively. The temperature dependent boundary spacing curves show the asymmetrically rolled Cu has significantly higher thermal stability, with the onset temperature of obvious grain coarsening being 40 degrees C higher than that for symmetrical rolled Cu. The enhanced thermal stability of asymmetrically rolled Cu can be attributed to the retardation of nucleation mainly realized by the improvement in microstructure homogeneity and the removal of local severely distorted structures. Our results demonstrate the feasibility of using asymmetrical rolling to improve the thermal stability of bulk SMG metals.
10.1016-j.matdes.2016.06.100	-1		A series of high-entropy alloys (HEAs) CuYZrTiHf (Z1), CuYZrAlHf (Z2) and CuYZrAlTi (Z3) were prepared by arc melting. All these HEAs mainly consist of hexagonal close-packed (hcp) dendrites and CuY-type body-centered cubic (bcc) interdendrite phases. The result affirmed that principal elements with hcp structure and suitable atomic size are beneficial to the formation of hcp dendrites. Specially, small content of amorphous phase appears in Z3 HEA, which is related to the increased melt viscosity and principal elements used for preparing bulk metallic glasses. The compressive strength and plastic strain of Z1 are 1340 MPa and 13.2%, indicating a plastic fracture. Z2 and Z3 HEAs have higher Vickers hardness and compressive strength but the plasticity is severely depressed. The electrochemical corrosion measurements in the seawater solution were carried on. Z1 and Z2 HEAs possess better corrosion resistance and Z3 has a higher pitting resistance. According to the observation of corrosion morphologies, the interdendritic region containing CuY-type phase is feasible to preferential corrosion.
10.1016-j.matdes.2016.09.038	-1		Cu-Cr alloys produced by powder metallurgy are widely used as contact materials in vacuum interrupters. The efficiency of these devices depends on material characteristics, in particular porosity and oxygen content. This paper focusses on densification and oxygen evolution in Cu and Cu-25 wt%Cr compacts during sintering. Chemical reactions and their relationships with sintering are studied by dilatometric and thermogravimetric analyses coupled with mass spectrometry. High density Cu compacts swell during sintering, due to the gas released in closed pores by Cu oxide reduction reactions. The addition of Cr hinders the sintering kinetics by a mechanical effect but prevents swelling phenomena by trapping the released oxygen in solid chromium oxide. The furnace atmosphere has a major effect as its reducing degree determines the chemical reactions. Under neutral atmosphere such as secondary vacuum, copper oxide reduction occurs at high temperature, when densification has already produced close pores. In Cu compacts, this leads to large swelling while in Cu-25 wt% Cr compacts the oxidation of Cr traps the oxygen in CR2O3 interfacial nodules. A reducing atmosphere such as diluted hydrogen flux reduces the Cu oxide at lower temperature, so that part of the released oxygen is evacuated out of the compact. This leads to lower swelling in Cu compact and to a reduced amount of chromium oxide in lower oxygen Cu-25 wt% Cr compacts, which results to better bonding between Cu and Cr particles. (C) 2016 Published by Elsevier Ltd.
10.1016-j.matdes.2016.10.020	7	irradiation; shear; grain; ta; deformation; size; radiation; voids; nanocrystalline; simulations; similar; void; temperature; irradiated; boundaries	Under intense heating and/or deformation, pure nanocrystalline (NC) metals exhibit significant grain coarsening, thus preventing the study of length scale effects on their physical response under such conditions. Hence, in this study, we use in-situ TEM heating experiments, atomistic modeling along with elevated temperature compression tests on a thermally stabilized nanostructured Cu-10 at% Ta alloy to assess the microstructural manifestations caused by changes in temperature. Results reveal the thermal stability attained in NC Cu-10 at% Ta diverges from those observed for conventional coarse-grained metals and other NC metals. Macroscopically, the microstructure, such as Cu grain and Ta based cluster size resists evolving with temperature. However, local structural changes at the interface between the Ta based clusters and the Cu matrix have a profound effect on thermo-mechanical properties. The lattice misfit between the Ta clusters and the matrix tends to decrease at high temperatures, promoting better coherency. In other words, the misfit strain was found to decrease monotonically from 12.9% to 4.0% with increase in temperature, leading to a significant change in flow stress, despite which (strength) remains greater than all known NC metals. Overall, the evolution of such fine structures is critical for developing NC alloys with exceptional thermo-mechanical properties.
10.1016-j.matdes.2016.11.024	-1		In this work we have observed the beneficial effect from the solid solution formation on the thermoelectric performance of (Cu2(1-x) Sb2xTe)(Ga2Te3)(3) upon Sb substitution for Cu. This substitution allows the different occupations of Sb in the crystal lattice, i.e. Sb at Cu sites with x <= 0.05 and at Ga sides with x >= 0.05, which has resulted in the Pisarenko relation does not exactly capture the measured Seebeck coefficient under assumed effective masses m*. The reduction of the lattice thermal conductivity (kappa(L)) has been quantified within the temperature range from room temperature to 723 K. Over the entire composition range, the kappa(L) value is reduced by 33% and 25% at temperature 723 K and 580 K, respectively. This observation is in a good agreement with the theoretical calculation based on the Callaway model used in the solid solutions. Along with the increasing of the mobility and electrical conductivity, the thermoelectric performance has been improved with the highest ZT value of 0.58 at 723 K, which is about double the value of intrinsic (Cu2Te)(Ga2Te3)(3).
10.1016-j.matdes.2016.11.029	-1		The antimicrobial and wear behaviour of metallic glass composites corresponding to the Cu50 + x(Zr44Al6)(50) (- x) systemwith x = (0, 3 and 6) has been studied. The three compositions consist of crystalline phases embedded in an amorphous matrix and they exhibit crystallinity increase with increasing Cu content, i.e., decrease of the glass-forming ability. The wear resistance also increases with the addition of Cu as indirectly assessed from H/E-r and H-3/E-r(2) parameters obtained from nanoindentation tests. These results are in agreement with scratch tests since for the alloy with highest Cu content, i.e., Cu56Zr38.7Al5.3, reveals a crack increase, lower pile-up, prone adhesion wear in dry sliding and higher scratch groove volume to pile-up volume. Samples with higher Cu content revealed higher hydrophilicity. Time-kill studies revealed higher reduction in colony-forming units for E. coli (gram-negative) and B. subtilis (gram-positive) after 60 min of contact time for the Cu56Zr38.7Al5.3 alloy and all the samples achieved a complete elimination of bacteria in 250 min.
10.1016-j.matdes.2016.11.035	1	shape; memory; shape memory; damping; martensite; martensitic; damping capacity; transformation; capacity; strain; superelasticity; temperature; cu-al-mn; shape memory effect; effect	In this study, Cu-Al-Mn-V alloyswith bcc phase separationwere designed through changing V andMncontents, resulting in complex microstructure consisted of L2(1) parent, small amounts of d(V, Mn) and 2H(gamma' 1) martensite. The amounts of d(V, Mn) phase and 2H(gamma' 1) martensite increase with the increase of V content. The results further show that the stabilization of stress-induced 2H(gamma'1) martensite from L2(1) parent occurs among all CuAl- Mn-V alloys during deformation. Thus the same alloy not only exhibits superelasticity, but also shape memory effect after unloading when heated. The superelasticity and shape memory effect are summarized to three situations. Situation I includes Cu63.7Al25.3V1.Mn-9(9.1) and Cu63.7Al25.8V2.2Mn8.3 alloys (at%), which have excellent superelasticity strains being up to 5.4% and 3.9% respectively. Cu63.8Al25.4V4.2Mn6.6 and Cu63.0Al26.2V4.7Mn6.1 alloys are situation II, and exhibit good shape memory effects being up to 3.5% and 3.9% respectively. The superelasticity and shape memory effect of Cu62.8Al26.2V2.6Mn8.4 alloy that is situation III are between the above two situations. The obtained resultsmay open an avenue to design copper-based shapememory alloys simultaneously have superelasticity and shape memory effect under the same composition and deformation temperature through applying stress.
10.1016-j.matdes.2017.04.017	-1		In this work, Cu-based microcomposites were fabricated by powder metallurgy of gas-atomized Cu-15wt% Fe alloy powder, followed by drawing to various strains. The microstructure evolution and the resultant mechanical and electrical properties were investigated by scanning electron microscopy, electron backscatter diffraction, and tensile testing, among other techniques. The results indicated that during drawing, the Fe phase evolved into nanoscale filaments along the longitudinal direction. With increasing drawing strain, both the Cu grains and the Fe filaments were refined gradually, giving rise to a mean thickness of approximately 25 nm for the Fe filaments at a total strain of 4.0. The iron oxides particles formed due to contamination of oxygen maintained unchanged during drawing process. In addition, it was found that an intermediate aging during the drawing can significantly enhance the electrical conductivity of the microcomposites without sacrificing their strength . The present process involving an initial powder with a homogenous distribution of Cu and fine Fe phases makes it possible to obtain microcomposites with an ideal combination of electrical and mechanical properties at lower drawing strain, compared to those produced by conventional casting methods.
10.1016-j.matdes.2017.09.030	-1		In this work, the stability and transformation of two kinds of TiC with different stoichiometries in Cu-Si melts are studied, respectively. It is found that the near-stoichiometirc TiC with fewer carbon vacancies (designated as TiCx), such as TiC0.9, is relatively stable in Cu-Si melts, while the non-stoichiometric TiC with more carbon vacancies (designated as TiCy), such as TiC0.6, is unstable. And TiCy tends to transform into TiCx. Meanwhile, some Ti element from TiCy will be dissolved into the melts. It is considered that the addition of Si influences the equilibrium between TiC with different stoichiometries and soluble Ti in Cu melts, which results in the transformation of TiC. According to the results, the stoichiometry of TiC must be controlled when it is used as the reinforced phase in Cu-Si alloys.
10.1016-j.matdes.2017.09.035	-1		The effect of nickel additions to tune the wear performance of Cu45.5Zr51Al3.5 at% alloy has been studied to present a new strategy for preventing excessive wear rate at high loads in metallic glass composites. This strategy consists on proper selection of a doping element in controlled concentrations with the ability to decrease the glass transition temperature (T-g) of the alloy so that the friction temperature during sliding is close to the Tg. This enables the formation of crystalline phases and their subsequent oxidation (lubricating layer) on the contact surface during sliding thus enhancing the wear resistance. Proper doping can also contribute towards the wear resistance when the content of the doping element promotes the martensitic transformation. The results show that the main wear mechanism for the three studied alloys (Cu45.5Zr51Al3.5, Cu45.5Zr51Al3.5Ni1 and Cu43.5Zr51Al3.5Ni2 at%) is governed by delamination and the mass loss increases with increasing load from 1 to 10 N. However, for the maximum load of 15N, the calculated friction temperature is close to Tg for the Ni-containing alloys and partial crystallization and oxidation take place resulting in a mass loss decrease from about 2.6 mg (at 10 N) to about 2.1 mg (at 15 N).
10.1016-j.matdes.2018.03.066	3	sma; shape; shape memory; memory; smas; superelastic; bars; damping; cu-al-mn; mechanical; bending; applications; numerical; sma bars; material	Cu-based shape memory alloys are potential substitutes of NiTi shape memory alloys, owing to their lower production costs and recent increase in mechanical properties arising from better control of the microstructure. The development of joining technologies for advanced materials is key to expand to the potential applications of any engineering alloy. In this work, laser welding of single crystal-like Cu-Al-Be shape memory alloys was performed. The microstructure and tensile properties were evaluated to understand the effect of laser welding on the microstructural and mechanical features of the welded joints. Cycling tests performed for a wide range of temperatures revealed that the joints possess extraordinary superelastic recovery after joining, with potential applications in damping devices due to the significant amount of energy that can be absorbed during superelastic deformation.
10.1016-j.matdes.2018.05.010	-1		Selective laser melting (SLM) was used to manufacture fully martensitic (beta'(1)) samples of the shape-memory alloy 81.95Cu-11.85Al-3.2Ni-3Mn (wt%). Crack-free specimens with a high relative density of about 98.9 +/- 0.1% were produced. Immediate remelting of already processed layers during SLM enhances the relative density (99.5 +/- 0.3%). Primarily by varying the scanning speed in the remelting step, the thickness of the remelted zone can be adjusted. Moreover, remelting alters the microstructure as well as the transformation temperatures, which tend to rise with the volumetric energy input. In this way, the shape-memory properties can be modified without compromising the relative density and the considerable plasticity of the samples. Thus, the remelting procedure proves to be an interesting tool for 81.95Cu-11.85Al-3.2Ni-3Mn and related alloys in order to optimize and tailor their performance already during SLM processing and without applying additional post-processing steps.
10.1016-j.matdes.2018.06.044	0	solidification; phase; magnetic; magnetic field; undercooling; field; liquid; separation; peritectic; immiscible; cu-; dendrite; phase separation; microstructure; primary	The metastable immiscible Cu80Fe20 alloys with different diameters were systematically investigated under conventional solidification. Experimental results indicated that the primary and second liquid-liquid phase separation simultaneously occur during solidification. The average size of primary phase-separated Fe-rich spherulites and the interior morphological pattern of minority Cu-rich phase can be greatly influenced by cooling rate due to the dynamic coupling between thermodynamic and kinetic effects. Moreover, various morphological patterns of minority Cu-rich phase in Fe-rich spherulites were observed, which discloses the dynamic evolution process during self-driven second liquid-liquid phase separation. The Marangoni migration, coalescence and coagulation, and Ostwald ripening are the dynamic mechanisms mainly responsible for various morphological patterns of minority Cu-rich phase after phase separation. Such a clear experimental observation of dynamic microstructure evolution for minority Cu-rich phase provides a strong and visualized evidence for the asynchronous crystallization behavior of primary phase-separated Fe-rich spherulites. Phase field simulation was also performed to reveal the dynamic evolution of minority Cu-rich phase during liquid-liquid phase separation. Besides, the experimental Cu80Fe20 alloys exhibit soft ferromagnetic characteristics possessing relatively low coercivity and high saturated magnetization. This present study provides a new strategy to design immiscible alloy with anticipated microstructure possessing tailored properties and desired functionalities.
10.1016-j.matdes.2018.07.003	-1		Multi-modal precipitate distribution in the microstructure, with coarse precipitates pinning the grain boundaries and finer precipitates strengthening the matrix, is beneficial to suppress grain boundary sliding and dislocation creep, respectively, of structural materials. However, achievement of a multi-modal precipitate distribution remains a challenge in developing creep-resistant advanced Cu alloys while retaining high strength and high conductivity at elevated temperature. This work overcame this challenge with the aid of computational thermodynamics. Thermodynamic models for Gibbs energy functions of phases in the Cu-Cr-Nb-Zr system have been developed in this study. These models were then used to calculate solidification paths and phase equilibria at different temperatures, guiding the design of chemical composition and heat treatment parameters of novel copper alloys with a target multi-modal distribution of precipitates. The new alloy, fabricated through traditional ingot metallurgy method, has achieved the desired microstructure as validated by optical and transmission electron microscopy. Electrical conductivity and mechanical properties were screened and compared with the existing commercial Cu alloys.
10.1016-j.matdes.2018.107564	-1		The present investigation demonstrates the synthesis of nanocrystalline Cu-0.5 at% Zr alloy through high energy ball milling at cryogenic temperature and thermal stability of the nanocrystalline structure during annealing up to 800 degrees C. The effect of Zr addition on the evolution of microstructure in the cryomilled and annealed alloy has been studied through X-ray diffraction (XRD), transmission electron microscopy (TEM), andMolecular dynamics (MD) simulation. Microhardness measurement has been performed in order to study the stability in the mechanical property of the alloy at high temperature. Analysis of XRD and TEM results show that at high-temperature Zr leaves Cu matrix and nano-size intermetallicCu(5)Zr particle dispersed throughout the matrix, whereas, MD simulation traced atomic clusters of Zr at the vicinity of grain boundaries. Zr stabilizes the average grain size in nano-scale regime even after 800 degrees C due to intermetallic pinning and solute segregation, with very little compromise in the hardness value of only similar to 7.4% (2.9 GPa to 2.4 GPa) compared to the as-milled alloy. (C) 2018 Elsevier Ltd. This is an open access article under the CC BY-NC-ND license
10.1016-j.matdes.2018.11.050	-1		Pure copper and Cu-Zn plates were friction stir welded under the same condition to evaluate the effect of stacking fault energy on the microstructural evolution and mechanical properties of the joints. For this aim, microstructure and texture of the joints were systematically characterized by electron backscattered diffraction and transmission electron microscopy. Moreover, to study the mechanical properties of the different microstructural zones of the joints, nanoindentation tests were employed. The results showed that in pure copper, continuous dynamic recrystallization was the only restoration mechanism for the formation of new grains. By adding zinc into copper, namely decreasing slacking fault energy, both continuous and discontinuous dynamic recryslallizalion mechanisms occurred. To this end, the enct of sucking fault energy on the restoration mechanisms has been summarized by schematic models. Moreover, the effect of the resloration mechanisms on the yield strength and strain hardening behavior of the joints has been scrutinized. (C) 2018 The Authors. Published by Elsevier Ltd.
10.1016-j.matdes.2019.107641	-1		Segregation in the solidification process and discontinuous precipitation during aging cause the service and processing performance of Cu-Ni-Sn alloys deteriorating severely. In this work, Si is added as a fourth element for the design of Cu80Ni15Sn5-xSix (x = 0, 0.625, 1.25, 1.875, 2.5) series alloys using cluster-plus-glue-atom model to solve these issues from the point of composition design. The results suggest that the introduction of Si leads to the disappearance of the lamellar structure formed in the as-cast alloys while also inhibiting discontinuous precipitation during aging. The solidus-liquidus temperature range is reduced with the addition of Si, and this strategy is most effective when the Si is in the solution state. With increasing Si content, the high-temperature conductive stability of the alloys is improved. Moreover, the hardness and conductivity of the Cu80Ni15Sn5 alloy designed by cluster-plus-glue-atom model are improved compared with those of C72900 (Cu78.96Ni16.65Sn4.39) commercial alloy, and the properties of Cu80Ni15Sn4.375Si0.625 alloy are basically equivalent to those of C72900 alloy. These findings indicate that alloys with excellent synthetic properties can be produced as long as the content and existential state of Si are reasonably controlled. (C) 2019 The Authors. Published by Elsevier Ltd.
10.1016-j.matdes.2019.107676	-1		Cu-3wt% Ag-1 wt% Zr alloys were well prepared by gas atomization followed by hot isostatic pressing (HIP) and forging. The effects of HIP temperature on the microstructure and mechanical properties of the as-HIPed and as-forged alloys were investigated, respectively. The alloy HIPed at 830 degrees C has an inhomogeneous microstructure with prior particle boundaries and fine network structure, and forging crushes the network structure into Cu4AgZr particles of 100-200 nm. The alloy HIPed at 950 degrees C exhibits a homogeneous microstructure with uniformly distributed Cu4AgZr particles in the range of 5 mu m, but forging has less effect on the particles. A relatively lower HIP temperature leads to the formation of finer grains and better grain-further-refining in the subsequent forging. Consequently, before and after forging, the alloy HIPed at 830 degrees C has a higher hardness and strength compared-with that HIPed at 950 degrees C. However, conventional solid solution and age-treatment have a limited effect on the mechanical properties of the alloys. The alloy HIPed at 830 degrees C followed by forging and aging has a yield strength, ultimate tensile strength, and elongation of 321 MPa, 454 MPa, and 39%, respectively. (c) 2019 The Authors. Published by Elsevier Ltd.
10.1016-j.matdes.2019.107814	-1		Cu-Mg binary alloys consist of a relatively simple mixture of eutectic reactions (L -> f.c.c. Cu + MgCu2). Since they have different color, i.e., the copper with L* = 86, a* = 14, b* = 16 and the MgCu2 with L* = 91, a* = 3, b* = 11, it can be suggested that the compositional tailoring can control the overall color of the alloys. In order to investigate the influences of the Mg contents on microstructure, color, and mechanical properties, series of the Cu-Mg colored near-eutectic and eutectic alloys were investigated for identifying color materialization and their properties, as well as the possibility of permanent color materialization in the metallic materials, was also investigated. With increase of Mg contents, the microstructure was transformed from a typical near-eutectic structure to MgCu2 polycrystalline structure, indicating the increased volume fraction of MgCu2 Laves-phase together with the enhanced hardness. In addition, the color variations expressed by means of L*a*b* color space migrated to the reduced a* and b* direction, suggesting the visual color of alloys changing from reddish orange color to pale yellow color. Therefore, these findings indicated that the combination of two different colored phases can lead to the permanent color variations in metallic materials without any additional processes. (C) 2019 Published by Elsevier Ltd.
10.1016-j.matdes.2019.107815	-1		In this study, the microstructures and electrical and mechanical properties of Cu-13 mass%Cr (1.3Cr) and Cu-2.5 mass%Cr (2.5Cr) alloy specimens fabricated by selective laser melting (SLM) were investigated. The effects of heat treatment on the microstructures and properties of the SLM specimens were also studied. Cu-Cr SLM specimens with a relative density of >99.7% were obtained. By annealing at 600 degrees C, the electrical conductivity of the SLM specimens significantly increased to maximum values of 91% IACS and 73% IACS for the 1.3Cr and 2.5Cr SLM specimens, respectively. Further, by annealing at 450 degrees C, the tensile strength and Vickers hardness of the SLM specimens also increased, with the tensile strength reaching maximum values of 640 and 777 MPa for the 1.3Cr and 2.5Cr SLM specimens, respectively. A close relationship was found between the changes in the properties and the nanostructures. By annealing, a line Cr phase precipitated from the supersaturated solid solution, which formed through rapid solidification by local laser irradiation. Therefore, the electrical conductivity increased because of the decrease in the solid-solute Cr. Meanwhile, the SLM specimens were strengthened because of age hardening by the precipitation of the fine Cr phase. (C) 2019 The Authors. Published by Elsevier Ltd.
10.1016-j.matdes.2019.107900	-1		Cu-Zn-Mn-Ni-Sn high-entropy (HE) and Cu-Zn-Mn-Ni medium-entropy (ME) brasses were designed and the ingots were fabricated by conventional casting process via metallic mold casting. The ingots of the equiatomic CuZnMnNi ME brass showed dendrite structures composed of body-centered-cubic (BCC) and face-centered-cubic (FCC) phases. A single FCC phase was obtained in the ingots of non-equiatomic CuxZnMnNi (x = 2, 3, and 4) ME brasses. The addition of Sn to CuxZnMnNi (x = 1, and 2) ME brasses significantly affected the solidification microstructure and the constituent phases. The ingots of the CuZnMnNiSn0.2 HE brass showed only sharp peaks corresponding to BCC phase in XRD patterns. The Sn addition to CuxZnMnNi (x = 1, and 2) ME brasses led to superior mechanical strength in the ingots. (C) 2019 The Authors. Published by Elsevier Ltd.
10.1016-j.matdes.2019.107964	-1		A major challenge for alloy applications is to achieve thermal stability of phase transitions and anti-oxidation properties. Given the stability of ceramic nanoparticles, we propose the incorporation of WC nanoparticles as a novel way to tune the thermal stability of Cu-40 wt% Zn, which is an important alloy known as naval brass. In situ XRD and DSC results confirmed the enhanced thermal stability of Cu-40 wt% Zn/10 vol% WC nanocomposites al higher temperatures were observed for both phase transitions and oxidation. The underlying mechanisms behind Zn diffusion during phase change and oxygen contact are discussed to understand the phenomena. Optical profiles along with SEM and FIB images reveal the morphologies and microstructures of different stages and give supporting information for the above argument. Due to the kinetic and dynamic impedance on Zn diffusion and the intrinsic stability of WC, the higher thermal stability in Cu-40 wt% Zn/WC is achieved. This study provides an effective way to tune thermal stability of alloys, control phase change, and vary post-oxidation morphology. (C) 2019 The Authors. Published by Elsevier Ltd.
10.1016-j.matdes.2019.107976	15	aging; strength; conductivity; electrical conductivity; electrical; mpa; treatment; strengthening; degrees; cu-; cold; precipitation; tensile strength; tensile; iacs	Deformed Cu-Cr alloys have high strength and high electrical conductivity and are used in highly-pulsed magnetic field coils, power vacuum fuses, and so on. In this paper, Cu-Cr-Zr alloy ingots were prepared by medium-frequency induction smelting. They then underwent a heat treatment, forging, cold drawing, and intermediate annealing to obtain a fiber material with a diameter of 0.8 mm. The Cu/Cr interface, precipitated phase, and Cu/Cr chemical mutual solution zone were observed by transmission electron microscopy. The mechanism by which the Cu/Cr interface affected the Cu-Cr-Zr alloy tensile strength was analyzed. The influence of chemical mixing of the Cu/Cr interface on the conductivity of the Cu-Cr-Zr alloy was also studied. The results showed that the Cu/Cr semi-coherent interface inhibited the formation of dislocations during large deformation, which gave the Cu-Cr-Zr alloy its high strength . Elimination of chemical mixing at the Cu/Cr interface allowed the conductivity of the Cu-Cr-Zr alloy to remain unchanged after extremely large deformation. (C) 2019 The Authors. Published by Elsevier Ltd.
10.1016-j.matdes.2019.108009	-1		A self-organized 2D nanolaminate with an average lamella thickness of similar to 22 nm was formed in the subsurface of a cold-sprayed WC-reinforced metal matrix composite (MMC) Cu-MoS2-WC during oscillatory sliding and it was responsible for the much more stable friction and improved wear resistance. Using high resolution transmission electron microscopy and nanoindentation, three important characteristics were observed in the nanolamellae that contributed to their great stability and high hardness. First, misorientation of the lamellar boundaries was low i.e. <3 degrees. Second, stacking faults and twins were main substructures. Lastly, the recrystallization was controlled by grain boundary nucleation, that required much higher driving force than triple junction nucleation. Such nanolaminate eliminated massive detachment and permitted small detached particles that tended to be trapped in the contact and experienced rapid recrystallization. The equiaxed nanograins on the top surface accommodated shear force by grain boundary-mediated deformation mechanisms, which could potentially benefit tribological performance. Observations of the tribologically induced microstructural evolutions near the surface showed the formation of self-organized tribomaterial with high hardness and stability, which was aided by the presence of WC particles. Considering the effectiveness of these microstructures, future design of wear resistant alloys may consider engineering these microstructures in the as-prepared state.
10.1016-j.matdes.2019.108075	5	materials; thermal; heat; properties; material; welding; sintering; fusion; strength; laser; heat sink; thermal conductivity; mechanical; sink; manufacturing	Cupronickel alloys such as 70/30 Cu-Ni have excellent resistance to seawater corrosion and anti-fouling properties, and thus have been widely used for naval and offshore applications. Traditionally, arc welding and brazing processes have been used to weld such materials. In contrast, laser beam welding is a promising technology due to its high productivity, good process flexibility and reliability, and good welding integrity. In the present work, a high power fiber laser system is used to weld 5-mm thick 70/30 Cu-Ni alloy plates in a configuration of butt joints. Then, the laser welded joints are evaluated in terms of microstructures, defects, and mechanical properties (hardness, face and root bend, and tensile) in accordance with the applicable International Organization for Standardization and Defence Standard specifications. Crown Copyright (C) 2019 Published by Elsevier Ltd.
10.1016-j.matdes.2019.108276	-1		Cu/Mg-composites, the copper matrix of which contains 1, 7 and 2730 magnesium filaments, were obtained by hyrdoextrusion at room temperature. The structure, mechanical and electrical properties of the deformed composite rods and thin wires were investigated. The yield strength and electrical resistivity were theoretically calculated and these estimations were compared with the experimental results. The XRD-method allowed discovering a change of the lattice constant of the Cu-matrix under deformation of the composites. It has been concluded that, under severe plastic deformation, a supersaturated Cu-based solid solution forms on the Cu/Mg-interface. As a result, the strength of the deformed Cu/Mg-composite with minimal volume fraction but maximal surface area of magnesium is abnormally high . A thick Cu-sleeve provides low electrical resistivity of this Cu/Mg-composite. The obtained results can be used for the development of high-strength Cu-based conductors. (C) 2019 The Authors. Published by Elsevier Ltd.
10.1016-j.matdes.2019.108406	-1		Characterized by high thermal-electrical conductivity and reasonable specific strength, lattice structures of copper alloy have great potential in industrial applications. However, they have been rarely studied due to their complicated structures and difficulty in fabrication. Based on the ability of selective laser melting to produce near net shape parts with any complex geometry directly, Cu-Cr-Zr copper alloy lattice structures with high density were manufactured and studied for the first time. A series of lattice structures were designed by a mathematical approach named Triply Periodic Minimal Surfaces and their mechanical properties. microstructures and deformation behaviors were systematically studied. The effects of cell size and volume fraction on their mechanical properties and energy absorptions were analyzed and evaluated. The results demonstrate that the mechanical and energy absorption properties of the lattice structures varied dramatically with the changes of cell size and volume fraction. Due to the good plasticity of the copper alloy, stress-strain curves of the lattice structures exhibit a long stress plateau without stress collapses, which is very beneficial for energy absorption. The deformation of the lattice structures occurred uniformly and was caused by the struts bending without cell breaking and struts fracturing. (C) 2019 The Authors. Published by Elsevier Ltd.
10.1016-j.matdes.2020.109248	-1		Copper alloys with high strength and electrical conductivity are ideal candidates for a wide range of civilian and engineering applications. Traditional methods of alloy design, such as trial and error experiments, are costly and time-consuming, limiting the discovery of Cu alloys. Machine learning (ML)-based technology facilitates a better understanding on inter-relationships within massive experimental datasets, and shortens the development cycle of new alloy systems. Herein, we propose a method of material design based on ML to discover high-performance Cu alloys. The ML models are trained from discarded experimental data that show undesirable hardness and/or electrical conductivity. We constructed effective Gaussian process regression-based models successfully from limited training data by engaging additional features. The predicted Cu alloys were experimentally synthesized and characterized, exhibiting superior hardness or electrical conductivity with respect to original training data. The increase of hardness is due to precipitation of second-phase Co-Ti and Fe-Ti compounds during aging, while the rise of electrical conductivity is caused by a purification effect of the precipitates on Cu matrix. The impact of physical features on ML models was further evaluated by a genetic algorithm. Our findings suggest that ML holds great potential for developing high-performance Cu alloys. (c) 2020 The Author(s). Published by Elsevier Ltd. This is an open access article under the CC BY license (http:// creativecommons.org/licenses/by/4.0/).
10.1016-j.matdes.2021.109625	3	sma; shape; shape memory; memory; smas; superelastic; bars; damping; cu-al-mn; mechanical; bending; applications; numerical; sma bars; material	Dense and crack-free specimens of the shape memory alloy (Cu716Al17Mn11.4)-Al-. (at%) were produced via laser powder bed fusion across a wide range of process parameters. The microstructure, viz. grain size, can be directly tailoredwithin the process and with it the transformation temperatures (TTs) shifted to higher values by raising the energy input. The microstructure, and the superelastic behavior of additively manufactured samples were assessed by a detailed comparison with induction melted material. The precipitation of the a phase, which inhibit the martensitic transformation, were not observed in the additively manufactured samples owing to the high intrinsic cooling rates during the fabrication process. Fine columnar grains with a strong [001]-texture along the building direction lead to an enhanced yield strength compared to the coarse-grained cast samples. A maximum recoverable strain of 2.86% was observed after 5% compressive loading. The first results of our approach imply that laser powder bed fusion is a promising technique to directly produce individually designed Cu-Al-Mn shape memory parts with a pronounced superelasticity at room temperature. (C) 2021 Published by Elsevier Ltd.
10.1016-j.matdes.2021.109857	-1		Despite of the promising capabilities of selective laser melting (SLM), the poor formability of copper and its alloys is a critical challenge for industrial applications, which is widely-believed attributed to the high reflectivity of copper. Due to the difficulty of observing laser reflections, current understanding on the laser reflection mechanisms is still vague and unclear. This work constructs a high-fidelity CFD model coupled with a ray-tracing method to visualize the flow kinetics and reflection behavior during SLM Cu-Cr-Zr alloy. Considering the material specificity of copper, a temperature-dependent absorption rule is introduced to overcome the simulation deviation caused by the widely-used Fresnel absorption, showing good agreement with experiments in terms of track width and depth . The in-situ absorptivity measurement experiments are further conducted to compare with simulations with the error less than 2%. Additionally, different reflection mechanisms for continuous and distorted tracks are revealed. At relatively high linear energy density (LED), the global absorptivity undergoes a rise and a decrease in the initial stage, and finally gets stable. At low LED level, the surface tension drives the melt pool to form isolated balls and exposed plat surface, which is responsible for the intense absorptivity oscillation as the balling effect occurs. (c) 2021 The Authors. Published by Elsevier Ltd. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/).
10.1016-j.matdes.2021.109929	-1		Cu-Ni-Co-Si alloys have been regarded as a candidate for the next-generation integrated circuits. Nevertheless, using the trial and error method to design high-performance copper alloys requires a lot of effort and time. Thus, the material design method based on machine learning is used to accelerate the exploitation of alloys. In this study, a composition-process-property database of Cu-Ni-Co-Si alloys was established, and a new strategy that could simultaneously realize the prediction of properties and the optimization of compositions and process parameters was proposed. Four groups were chosen from 38,880 candidates by the multi-performance screening method; good agreements existed between the prediction and the test. The Cu-2.3Ni-0.7Co-0.7Si alloy had the best performance among the designed alloys, and this alloy was studied in depth . The influence of the dissolution of Co in Ni2Si was analyzed from a novel perspective. Interestingly, the trace amount of Co replacing Ni to form (Ni, Co)(2)Si increased the phase dissolution temperature dramatically and shortened the coarsening rate. Affected by Co, the over-aging process was slowed down, which broadened the use range of alloys greatly. Therefore, the developed Cu-2.3Ni-0.7Co-0.7Si alloy can prove to be promising materials that meet different working conditions, and its performance was better than C70350 alloy. (C) 2021 The Authors. Published by Elsevier Ltd.
10.1016-j.matdes.2021.110081	-1		An experimental evaluation of the microstructure, mechanical and functional fatigue properties of the Cu-11.70Al-0.45Be doped with Bx (x = 0.05, 0.10, 0.12, and 0.14 wt%) SMA wires has been carried out. The experiments were performed to investigate microstructure, phase/precipitates, and transformation temperatures for both as-cast and wire samples. Furthermore, tensile properties, shape recovery ratio, and functional fatigue evaluation have also been carried out for the wire samples. The investigation shows that the addition of the minor amount of boron and secondary processes involved during the specimen preparation induced excellent grain refinement. The addition of boron decreased transformation temperatures; however, there was not a considerable change observed due to the secondary process. It was observed that tensile properties increases with the boron addition, and complete shape recovery was observed for all the selected alloys. Finally, functional fatigue tests were conducted under constant stress condition and observed that the number of cycles until the failure has increased and more distance recovery was achieved with an increase in boron doping. (c) 2021 Published by Elsevier Ltd. This is an open access article under the CC BY-NC-ND license (http:// creativecommons.org/licenses/by-nc-nd/4.0/).
10.1016-j.matdes.2021.110270	-1		In this work, a functionally graded material (FGM) part was fabricated by depositing a Cu-based alloy on top of a high strength low alloy (HSLA) steel by twin-wire and arc additive manufacturing (T-WAAM). Copper and steel parts are of interest in many industries since they can combine high thermal/electrical conductivity, wear resistance with excellent mechanical properties. However, mixing copper with steel is difficult due to mismatches in the coefficient of thermal expansion, in the melting temperature, and crystal structure. Moreover, the existence of a miscibility gap during solidification, when the melt is undercooled, causes serious phase separation and segregation during solidification which greatly affects the mechanical properties. Copper and steel control samples and the functionally graded material specimen were fabricated and investigated using optical microscopy, scanning electron microscopy, and high energy synchrotron X-ray diffraction. Retained d-ferrite was found in a Cu matrix at the interface region due to regions with mixed composition. A smooth gradient of hardness and electric conductivity along the FGM sample height was obtained. An ultimate tensile strength of 690 MPa and an elongation at fracture of 16.6% were measured in the FGM part. (c) 2021 The Author(s). Published by Elsevier Ltd. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/).
10.1016-j.matdes.2021.110278	-1		Unalloyed copper (Cu) powder was deposited and melted onto a pre-existing stainless steel substrate using electron beam powder bed fusion (EB-PBF) additive manufacturing (AM) to form dense, bimetallic structures. The AM fabricated Cu was fully dense, and with strength properties consistent with recent reports on EB-PBF of Cu. The overall bimetallic structures exhibited total elongation of 25-35%, and was dominated by plastic deformation in the Cu region. Tensile failures were typically observed in the Cu portion of the bimetallic bodies demonstrating that the interface was not the source of mechanical failure. The interface region of the bimetallics contained areas of liquid phase separated Cu and Iron (Fe) + Chromium (Cr) rich regions resulting from a metastable miscibility gap in the Cu and Fe phase diagram. Metallurgical and mechanical examinations of the bimetallic structures showed the interface region transitions from an Fe rich mixture to a Cu rich mixture within a few AM layers. (c) 2021 The Authors. Published by Elsevier Ltd. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/).
10.1016-j.matdes.2021.110340	-1		Cu-Be alloys provide excellent electrical and mechanical properties, but present serious health hazards during manufacturing. Among alternative alloys, the Cu-Ti system has the highest yield strength; however, Ti cannot be easily solutionized at concentrations above 4 wt%, resulting in a relatively low formability. In this study, Cu-xTi-yFe (x = 3, 5, 6 wt% and y = 0, 0.3 wt%) alloys were studied after both solution-annealing and age-hardening through mechanical testing and microstructure analysis. Micro-additions of Fe kept high concentration of Ti in solid solution (up to 6 wt%) after water quenching and suppressed the classical wave-like early-stage precipitation. Instead, a new dispersion of nano precipitates was observed. This behavior results in doubling the ductility in the solution annealed state (up to 48% elongation), together with maintaining a very high strength after ageing (up to 975 MPa) from precipitation of metastable nano alpha-Cu4Ti. This study shows that Fe micro-additions, when combined with a higher amounts of Ti (6 wt%), enables the production of Cu-based alloys combining high formability and strength, providing an excellent alternative to Cu-Be in mechanical applications. (C) 2021 Published by Elsevier Ltd.
10.1016-j.matdes.2022.110410	-1		Two nano-scaled hexagonal distortions in high temperature BCC phase during cooling is commonly observed in many alloys systems. Although efforts have been made on studying the lattice softening of the BCC structure during cooling, the distortion mechanisms are less addressed. Thus, the formation of two hexagonal structures in the beta precipitates in a Cu-40Zn alloy treated by ECP was thoroughly investigated. Results show that the beta precipitates contain two kinds of nano-sized and diffuse atomic clusters one with a eta structure obeying the Burgers OR and the other a omega structure obeying the Blackburn OR. They were each formed through a two-stepped atomic displacement. For the eta structure, the first step is the atomic shuffle of each second {110}(beta) plane in the <1<(1)over bar>0> (beta) direction and the second is a structure change mainly by a {1 (1 ) over bar2} < <(1)over bar>11> (beta) shear. For the omega structure, the first is an atomic shuffle on each second and third {11 (2) over bar}(beta) plane in the +/- [1 1 1 ](beta) directions and then normal strains in three mutually perpendicular directions. The concomitant formation of the two structures minimizes the lattice distortion of single formation. The present results provide new information on the formation mechanism of the two hexagonal structures in a BCC matrix. (C) 2022 The Authors. Published by Elsevier Ltd.
10.1016-j.matdes.2022.110420	10	composites; nanoparticles; strength; matrix; high; strengthening; particles; conductivity; composite; electrical; mpa; sintering; ods; grains; mechanical	Metallic glass (MG)-particle-reinforced nanocrystalline CuCrZr alloys with ultrahigh strengths and good conductivities are designed and synthesized via mechanical milling and spark plasma sintering (SPS). The particle morphology and dispersion state of the CuZrAl MG reinforcement in the CuCrZr alloy matrix are optimized by regulating the milling time of the composite powders prior to SPS consolidation. Outstanding properties are achieved by 5 h and 10 h milling processes with ultimate compressive strengths of 1099 +/- 33 and 1185 +/- 29 MPa and high conductivities of 29.9 +/- 0.8% IACS and 25.2 +/- 0.6% IACS, respectively. According to the quantified results of strengthening and conductivity mechanisms, MG reinforcements and ultrafine grains are responsible for the balance of superior strength and conductivity of the composites. (c) 2022 The Authors. Published by Elsevier Ltd. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/).
10.1016-j.matdes.2022.110519	-1		Laser powder bed fusion (PBF-LB/M) of bulk metallic glasses permits large and complex components to solidify to an amorphous state, thus expanding the processing possibilities of this material class. Here, the Cu-Ti-Zr-Ni family, also known as Vitreloy 101, is systematically investigated for processing of the PBF-LB/M powder itself. Gas atomization was used to produce powder of Vit101 and derivates micro-alloyed with Si and Sn. The influence of atomization and alloy composition on glass formation, oxygen content, particle morphology, and flowability were investigated. Amorphous powder was successfully obtained using industrial-grade purity as feedstock for the atomization. The oxygen content within the powder was controlled by the surface-to-volume ratio, without significant influence of the different atomization parameters and the microalloying itself. The powder displayed high circularity with sufficient flowability after drying. Our results contribute to the investigation of Vitreloy 101 alloys as promising candidates for PBF-LB/M applications. (C) 2022 The Author(s). Published by Elsevier Ltd. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/).
10.1016-j.matdes.2022.110777	-1		Cu alloys can be plastically deformed to reach ultra-high strength, but often at an expense of their electrical conductivity. Here we report that the introduction of hierarchical precipitations and the resultant microstructural heterogeneities at different scales could overcome the strength-conductivity tradeoff in Cu-Ag-Zr alloy. The intrinsic particle size dependent precipitation behavior, owing to the different cooling rate during powder atomization, has been inherited after hot isostatic pressing (HIP) of powders into bulk sample. The following cold rolling and aging created multi-scale structures with the sub-micron particles at grain boundaries and sub-micron-to-nano scale precipitates in the grain interior. Those introduced heterogeneous precipitate configurations also altered the evolution of deformation structures during cold rolling and aging, with partially recrystallized grains embedded in highly deformed matrix featured by high density of dislocation and substructures, which results in an excellent combination of tensile strength (704 MPa), electrical conductivity (88.7% IACS), and tensile elongation (14.9%). Besides, no significant coarsening in the micro-nano structures is observed after annealing at 450 degrees C for 1 h . The findings in this work proposed a novel approach for designing high-strength, high-conductivity, and high-thermal stability copper alloys based on hierarchical precipitation-stimulated structures at nano-to-micron scale. (C) 2022 Published by Elsevier Ltd.
10.1016-j.matdes.2022.110784	-1		Cu-Cr-Nb alloys have attracted many researchers' interest for decades while their structure and second phases inside were unclear. We have characterized the second phase particles formed during solidification, hot rolling, and aging treatments in a Cu-4.06Cr-1.25Nb alloy. Face-centered-cubic (FCC) Cr, L1(2) Cr3Cu, C14 Cr2Nb, C15 Cr2Nb, and Nb-rich particles were detected in the alloy. The crystal structure, precipitation, phase transformation behavior and orientation relationship (OR) were uncovered. C15 Cr2Nb particles formed in the solidification process while C14 Cr2Nb particles precipitated as aged at 600 degrees C. The competition of nucleation between nano-scale Cr3Cu and Cr2Nb particles aged at 600 degrees C was discussed. The nucleation of L1(2) Cr3Cu was prior to that of C14 Cr2Nb, and the precipitation of Cr2Nb particles would limit the coarsening of Cr particles. A phase transformation map during age treatment was established on the basis of transmission electron microscope (TEM) images and X-ray diffraction (XRD) patterns. These findings are helpful in developing high-performance Cu-Cr-Nb alloys. (C) 2022 Published by Elsevier Ltd.
10.1016-j.matdes.2022.110896	11	glass; bulk; metallic; bulk metallic; gfa; bmg; glassy; metallic glass; ability; bulk metallic glass; amorphous; addition; crystallization; mm; glass-forming	The influences of Ag and Co additions on the thermal stability and glass-forming abilities of twenty (Cu46-xZr47Al7Agx)(100)Co--y(y) (x = 0, 1, 2, 3, 4 and y = 0, 0.5, 1, 1.5) alloys were systematically investigated by X-ray diffraction and differential scanning calorimeter techniques. The mechanical performances (i.e., hardness, strength, and plasticity) of the alloys were evaluated, and the plasticization mechanisms of four representative (Cu46-xZr47Al7Agx)(100)Co--y(y) specimens were discussed based on the observations of scanning electron microscopy and high-resolution transmission electron microscopy. It is found that (Cu43Zr47Al7Ag3)(99.5)Co-0.5 bulk metallic glass exhibits excellent thermal stability and improved plasticity after compression tests. The improvement can be attributed to the large amount and density of shear bands, the coexistence of a large area of smooth regions, the vein-like pattern, and the river-like pattern on the fractures. More importantly, the new-formed B2-CuZr phases and nanocrystallines during compressive tests also contribute to the improved plastic deformation ability by exalting the number and density of shear bands. (C) 2022 Published by Elsevier Ltd.
10.1016-j.matdes.2022.111033	-1		Producing high-strength and high electrical conductivity Cu-Ni-Si alloys from as-cast state to thin strips is a challenging issue in the industry, as high-temperature homogenization, multi-step rolling, and aging processes are frequently employed and, any mistakes in each step can affect the quality of the product. In the present study, the comprehensive properties of an as-cast Cu-Ni-Si alloy were improved by a short process, i.e., continuous extrusion combined with rolling and aging processes, without homogenization treatment. The results indicated that both the mechanical and electrical properties of the alloy at the optimized route were dramatically enhanced. A final microstructure containing fine grain sizes, massive precipitates, and dislocations was obtained, thus contributing to high tensile strength (763 MPa), high electrical conductivity (49.6% IACS), and good ductility (5.8% fracture elongation). The strengthening mechanisms were then quantitively calculated. The results showed that the dislocation strengthening, grain boundary strengthening, and precipitation strengthening take 25.2%, 16%, and 51.2% of the total yield strength, respectively. It has also been found that there are two sizes of precipitates and both were identified to be d1-Ni2Si. Although the volume fraction of the fine Ni2Si is small, it contributes to a large portion of the yield strength . Hence, there is great potential to control the precipitate size to enhance the strength of the Cu-Ni-Si alloy further for this combined technique. (c) 2022 The Authors. Published by Elsevier Ltd. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/).
10.1016-j.matdes.2022.111210	5	materials; thermal; heat; properties; material; welding; sintering; fusion; strength; laser; heat sink; thermal conductivity; mechanical; sink; manufacturing	The present work focuses on the possibility of manufacturing multi-material structures by spark plasma sintering (SPS), thereby broadening the field of application of this process by taking full advantage of the specific properties of individual materials. As a combination of dissimilar materials to be co-processed, CuCrZr and nickel are of particular scientific and technological interest. For the processing of complex 3D multi-material geometries made of highly dissimilar materials, the sintering behavior of each individ-ual material should however be as identical as possible. Since both materials have different physical and mechanical properties, the sintering behavior of the two individual powder materials is first character-ized at different uniaxial pressures, heating rates and holding times. A strategy to determine optimal sin-tering conditions for the processing of multi-material structures is then developed, based on representation of the densification data of each material in the form of master sintering curves (MSC) and surfaces (MSS). From the MSS, an optimal uniaxial pressure of 35 MPa was determined and the hold-ing time to achieve dense multi-material structures at a temperature of 1223 K was estimated. Different configurations of CuCrZr-Ni multi-material samples were successfully sintered using these parameters and microscopic analyses showed that the relative density in these parts is >99.8, in both CuCrZr and Ni.(c) 2022 The Author(s). Published by Elsevier Ltd. This is an open access article under the CC BY license (http://creativecommons.org/licenses/by/4.0/).
10.1016-j.matdes.2023.111873	6	grain; deformation; strain; strength; dislocation; cu-; tensile; size; ecap; grain size; sfe; ductility; hardening; high; stress	To realize the application of ultrafine-grained (UFG) materials in micro-forming, the micro/mesodeformation and fracture behavior of UFG pure copper processed using equal-channel angular pressing were analyzed by making in/ex-situ observations during tensile testing. The evolution of surface cracks and inner voids was apparent in the in-situ scanning electron microscopy (SEM) images and synchrotron radiation X-ray tomograms, respectively. The results indicate that the surface-crack evolution of UFG pure copper can be correlated with strain localization when the flow stress decreases after peaking. The effects of grain size and shear texture on damage evolution during the fracture process are also discussed. This work comprehensively explores the plasticity and fracture/failure mechanisms in UFG Cu samples during the micro-forming process.& COPY; 2023 The Author(s). Published by Elsevier Ltd. This is an open access article under the CC BY license (http://creativecommons.org/licenses/by/4.0/).
10.1016-j.matdes.2023.111898	-1		In order to clarify the effect of Fe-based amorphous alloy on the separation mechanism and corrosion behavior of Cu-based immiscible coatings, 10 wt% Fe-based amorphous powder was designed into 90 wt% pure Cu powder to produce the amorphous alloy reinforced Cu-based immiscible coatings by laser melting deposition. The self-organized microstructure and corrosion behavior of immiscible coatings with different laser energy densities were investigated. When the different laser energy densities are adopted, many carbides (M23C6 and M12C) are dispersed in the lower a-Fe layer and large amounts of a-Fe particles containing carbides are embedded in the upper e-Cu layer due to liquid phase separation. With increasing laser energy density (LED), the a-Fe dendrites are coarser and the area of carbides decrease. The interface of coating and substrate experiences a transition from poor bonding (gaps) to good bonding and crack debonding. Moreover, the corrosion characteristics of immiscible coatings also experience a transformation from crevice corrosion to enhanced protection of passive films and reduced protection of passive films. As a result, the corrosion resistance increases first then decreases and the immiscible coating deposited by the LED of 31.25 J/mm2 exhibits the highest corrosion resistance.& COPY; 2023 The Authors. Published by Elsevier Ltd. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/).
10.1016-j.matdes.2023.112109	-1		Scaling is a universal issue encountered in pipeline steel during offshore oil extraction. In this paper, a synergic anti-scaling Cu-Zn-CeO2 coating on the pipeline steel substrate was fabricated by one-step com-posite electrodeposition and magnetic stirring. It shows the wettability transition from superhydrophilic to superhydrophobic of the multi-scale structured Cu-Zn-CeO2 coating without low-surface-energy mod-ification after heating at 60celcius for 60 min and stored in air for ti 35 days. The wettability transition is owing to the hydrocarbons adsorption. The heating treatment and the multi-scale structure improve the hydrocarbons adsorption and reduce the transition time. The inherent hydrophobic CeO2 is beneficial for the superhydrophobic property and reduces the transition time. Compared with the steel substrate and previous superhydrophobic Cu and Cu-Zn coatings, it indicates the superhydrophobic Cu-Zn-CeO2 coating shows the promising synergic anti-scaling property due to its superhydrophobicity and the anti-scaling property of Cu-Zn alloys. This eco-friendly synergic anti-scaling Cu-Zn-CeO2 coating also shows excellent self-cleaning and anti-fouling properties. Moreover, the stability of the superhydropho-bic Cu-Zn-CeO2 coating was enhanced compared with our previous superhydrophobic Cu-Zn coating due to CeO2 nanoparticles. This research enriches the theory and the technology of the wetting field, which also provides a technical basis for solving scaling problems of pipelines. & COPY; 2023 The Authors. Published by Elsevier Ltd. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/).
10.1016-j.matdes.2023.112292	15	aging; strength; conductivity; electrical conductivity; electrical; mpa; treatment; strengthening; degrees; cu-; cold; precipitation; tensile strength; tensile; iacs	Improving high-temperature strength and resistance to high-temperature softening is an important method to promote the application of high-performance Cu-Cr-Zr alloy in fields such as resistance welding electrodes and high-speed railway contact wires. A Cu-1.0Cr-0.4Zn-0.1Zr-0.05Si alloy was designed and the combining effects of Zn and Si elements on the microstructure and high-temperature mechanical properties of the alloy were studied. The tensile strength of the alloy at room temperature was 556 MPa, and it was 349 MPa at 500 & DEG;C with a softening temperature of 620 & DEG;C. The main strengthening phases of the alloy were submicron Cr3Si and nano-scaled Cr-rich precipitates. The Zn elements were uniformly solid-solved in the Cu matrix, and the addition of Zn and Si elements significantly retarded the phase transformation of the Cr-rich precipitates. Thermodynamics and kinetics analysis showed that Zn and Si elements promoted the dispersive precipitation of the nano-scaled FCC coherent Cr-rich precipitates by reducing the nucleation energy barrier, while the Si and Zr elements inhibited the coarsening of the Cr-rich precipitates by enriching at the phase boundaries, effectively impeding dislocation motion and grain boundary migration, which mainly contributed to good high-temperature strength and resistance to softening of the Cu-Cr-Zn-Zr-Si alloy.
10.1016-j.matdes.2023.112445	15	aging; strength; conductivity; electrical conductivity; electrical; mpa; treatment; strengthening; degrees; cu-; cold; precipitation; tensile strength; tensile; iacs	The precipitation strengthening can significantly increase the strength but inevitably sacrifices the electrical conductivity of Cu-Ni-Sn alloys. In this study, a Cu-9Ni-6Sn alloy was aged at various temperatures for different durations and then subjected to severe plastic deformation. When the alloy was aged at 400 degrees C for 36 h, the uniformly distributed fine precipitates totally transitioned to discontinuous precipitates. And formed nanofibers of intermetallic compounds after plastic deformation. The tensile strength and electrical conductivity of the treated alloy were 1178 +/- 3 MPa and 25.0 +/- 0.1 % IACS, respectively, which were close to those of Cu-Be alloys. Compared to traditional alloys, the strength and conductivity were both improved. The main strengthening mechanisms were dislocation and fiber strengthening. Considering these mechanisms, the theoretical yield strength was determined to be 1091 MPa, which was close to the experimental value. This work provides a new approach for the preparation of copper alloys with excellent comprehensive performance.
10.1016-j.matdes.2023.112544	-1		Control over the microstructure and properties of alloys produced via additive manufacturing (AM) is a key barrier that limits widespread industrial adoption. Herein we demonstrate that liquid metal jetting (LMJ), an emerging metal-AM technique, can address this need by controlling the microstructure evolution during printing of bronze alloy C95400 (Cu-Al-Fe-Mn). We probed several solid-state phase transformations upon cooling by printing single-tracks onto a heated baseplate ranging from 50 degrees C to 600 degrees C surface temperature, which led to significant variation in the alpha-Cu and delta-Fe phase distribution, grain morphology, and chemical distribution within the deposited single-tracks. The printed microstructures exhibited as much as 80% difference in alpha-Cu grain size and nearly 30 % difference in alpha-Cu phase fraction due to baseplate temperature variation, indicating a wide range of available microstructures and properties achievable. Greater than 92% dense multi-layer samples were fabricated with fine grain structure and 27-34% higher hardness values compared to the barstock in the asprinted condition, demonstrating the applicability of this printing approach for multi-layer part fabrication. Our results highlight a unique microstructure tailoring capability for metal-AM parts that can be leveraged by manufacturers and end-users of AM technologies.
10.1016-j.matdes.2023.112555	-1		Copper-graphene composites show remarkable electrical performance surpassing traditional copper conductors albeit at a micron scale; there are several challenges in demonstrating similar performance at the bulk scale. In this study, we used shear assisted processing and extrusion (ShAPE) to synthesize macro-scale copper-graphene composites with a simultaneously lower temperature coefficient of resistance (TCR) and improved electrical conductivity over copper-only samples. We showed that the addition of 18 ppm of graphene decreased the TCR of C11000 alloy by nearly 11 %. A suite of characterization tools involving scanning and transmission electron microscopy along with atom probe tomography were used to characterize the grain size, crystallographic orientation, structure, and composition of copper grains and graphene additives in the feedstock and processed samples. We posit that the shear extrusion process may have transformed some of the feedstock graphene additives into higher defect-density agglomerates while retaining the structure of others as mono-to-tri-layer flakes with lower defect density. The combination of these additives with heterogeneous structures may have been responsible for the simultaneous decrease in TCR and enhanced electrical conductivity of the copper-graphene ShAPE composites.
10.1016-j.matdes.2023.112586	15	aging; strength; conductivity; electrical conductivity; electrical; mpa; treatment; strengthening; degrees; cu-; cold; precipitation; tensile strength; tensile; iacs	Single-crystal copper rods with high conductivity and mechanical properties are the decisive material for the production of microwires for chip bonding. To further improve the product of strength and elongation as well as electrical conductivity, rare earth Y is added to a single-crystal copper rod to adjust the microstructure and impurity state. The results show that Cu-0.03Y copper rods have excellent comprehensive properties. The electrical conductivity improves to 103.72 % IACS, and the product of strength and elongation improves to 8.772 GPa%. The precipitates in the Cu-0.03Y single crystal copper rod are nano-sized spherical particles composed of YP (NaCl type) and Cu5Y (Cu5Ca type) phases. The enthalpy of formation of Y and P is calculated using Miedema thermodynamics as Delta H = -173.45 kJ & sdot;mol- 1. The precipitates formed by the preferential reaction of Y and P reduce the solid dissolved atoms in the copper, and the electrical conductivity increases accordingly. The (001) texture of a single-crystal copper rod decreases with the addition of Y, while the (101) texture increases with good plasticity, leading to an improvement in elongation.
10.1016-j.matdes.2024.112666	-1		Unconventional double-peak age strengthening phenomenon has occasionally been observed in some alloys, yet the underlying mechanism responsible for this phenomenon are still unclear. Here, we for the first time report the double-peak age strengthening phenomenon in the Cu-Be-Ni-Co alloys and try to unveil the underlying mechanism. Both the theoretical and experimental analyses demonstrate that the strong coherency strengthening effect of tiny nanoprecipitates (<1 nm) contributes significantly to the appearance of first peak, whereas the order-to-Orowan strengthening transformation accounts for the appearance of second peak. Moreover, the precipitate evolution processes of the alloys are identified as Guinier-Preston (GP) zones -> gamma ''-> gamma ' and the lightmass Be atoms in the gamma ' phase are directly made out by using integrated differential phase-contrast scanning transmission electron microscopy (iDPC-STEM) technology. Our work may provide new insights into the coherency strengthening effects and demonstrates a powerful strategy for designing high performance via doublepeak behavior.
10.1016-j.matdes.2024.112833	15	aging; strength; conductivity; electrical conductivity; electrical; mpa; treatment; strengthening; degrees; cu-; cold; precipitation; tensile strength; tensile; iacs	A new Cu-1.5Ni-0.7Co-0.7Si-0.3Fe-0.1Mg alloy with low cobalt content was designed. Multi-stage thermo-mechanical treatment (MTT) was used to produce the high-performance alloy with hardness of 286 HV, yield strength of 858 MPa, tensile strength of 910 MPa and electrical conductivity of 45.4 % IACS. The addition of 0.3 wt% Fe element dissolved in (Ni,Co)2Si 2 Si resulted in the formation of the orthorhombic S- (Ni,Co,Fe) 2 Si. During MTT, the S- (Ni,Co,Fe) 2 Si, (Ni,Co)2Si, 2 Si, beta- Ni 3 Si, and Fe2Si 2 Si precipitated successively near the deformation microstructure. Transmission electron microscope observations indicated that the S- (Ni,Co,Fe) 2 Si precipitates showed disc-like and rod-like shapes at different orientations, respectively. A new resource-saving, high-strength and medium-conductivity Cu-Ni-Co-Si-Fe-Mg alloy was prepared by replacing an equal amount of Co element with 0.3 wt% Fe element, reducing the amount of scarce metal Co in the alloy.
10.1016-j.matdes.2024.112931	14	strength; properties; conductivity; electrical; mechanical; cu-; grain; mpa; electrical conductivity; aging; precipitation; phase; mechanical properties; tensile; phases	This investigation aimed to design a thermally stable microstructure of an ITER-grade Cu-0.7Cr-0.07Zr alloy. The chosen approach involved employing a novel Equal Channel Angular Pressing (ECAP) at cryogenic temperatures (CT), in which the temperature was strictly controlled, followed by subsequent ageing. Post-ECAP ageing at 400 degrees C for 15 min resulted in a substantial enhancement in yield strength in CT -processed specimens, with a remarkable increase of 22% in comparison to their pre -aged counterparts. Additionally, ageing under these conditions yielded a more stable microstructure at elevated temperatures, with average grain size variation below to 1 mu m. The observed stability was attributed to the formation of fine Cr-rich precipitates during ageing that hinder grain boundary motion, thereby preventing grain growth and potential softening of the CuCrZr alloy. These findings elucidate a promising thermomechanical processing avenue for strengthening microstructures processed by cryogenic severe plastic deformation and/or exposure to elevated temperatures. Finally, the adopted processing route in this study not only facilitated but distinctly culminated in attaining the paramount strength/ductility relationship for CuCrZr alloys with a stable microstructure at medium -to -high temperature range.
10.1016-j.matdes.2024.113220	14	strength; properties; conductivity; electrical; mechanical; cu-; grain; mpa; electrical conductivity; aging; precipitation; phase; mechanical properties; tensile; phases	The primary objective of this study is the development of Cu/Nb composite materials for Superconducting RadioFrequency (SRF) applications under extreme service conditions characterized by a strong RF electromagnetic field, extremely low temperatures, and relatively low heat loss. A novel integrated manufacturing approach is proposed, which combines cold-sprayed AgCuTi alloy as an intermediate coating on the Nb surface and an electroplated Cu layer with a subsequent heat treatment brazing effect. This strategy aims to address the significant challenge of non-intermelting Cu and Nb while also considering effective lateral heat transfer. Mechanical property tests showed that the bond strength of Nb/AgCuTi/Cu composites exceeded 150 MPa. Lowtemperature thermal transport tests indicate that the Residual Resistance Ratio (RRR) of the Cu layer surpasses 150, with a thermal conductivity at 4.2 K exceeding 1600 W/(m & sdot;K). Moreover, both the composite interface and mechanical properties of the specimens remain stable even after undergoing cyclic cold shock experiments. These findings suggest that the Nb/AgCuTi/Cu composite material developed in this study meets the technical requirements for long-term stable and high-performance operation in high-current and high-power superconducting accelerators.
10.1016-j.matdes.2025.113599	-1		Micro-alloying and thermo-mechanical treatments are crucial to the further development of high-strength and high-conductivity Cu-Cr-X alloys. In this study, a high accuracy ultimate tensile strength and electrical conductivity prediction model was obtained by training the BP neural networks with different compositions and processing experimental data. The Cu-Cr-Zr-Mg-Ti alloy with superior properties was optimally designed by genetic algorithm from the massive solutions, which the experimental tensile strength and conductivity reached 668 MPa and 71.5 %IACS, respectively. The atom probe tomography results show that Zr, Mg, and Ti simultaneously segregated in the Cr-rich phase after aging at 440 degrees C for 480 h, which significantly improves the stability of the precipitated Cr phase and inhibited the Cr-rich phase transition from fcc to bcc structure. With the increase of aging temperature, the bcc structure Cr phase gradually replaces the fine fcc-Cr phase and exhibited a higher coarsening rate. It was found that the addition of Zr tends to nucleation at the interface of the K-S orientation relationship (OR) bcc-Cr phases. The Cu5Zr phase maintains the (113)Cu5Zr//(011)Cr and [011]Cu5Zr// [111]Cr ORs with the bcc structure Cr precipitates. The evolution of microstructure and properties exhibited a narrow aging process region of 80 % cold-rolled Cu-Cr-Zr-Mg-Ti alloy, while the consistent results from prediction model provide a favorable guidance for process designs. The outstanding performance enhancement and rapid prediction of process scopes leads us to recognise that the great potential of multi-objective machinelearning-aid design in the complex composition and process problems.
10.1016-j.matdes.2025.113602	15	aging; strength; conductivity; electrical conductivity; electrical; mpa; treatment; strengthening; degrees; cu-; cold; precipitation; tensile strength; tensile; iacs	To further regulate the coordinated matching of mechanical properties and plastic deformation ability of Al2O3/ Cu composites. In this paper, Al2O3/Cu-Cr composites with different Cr contents were prepared by replacing some Al2O3 particles with Cr using a deformation heat treatment process, and the effects of Cr contents on the microstructure, electrical conductivity, and mechanical properties of Al2O3/Cu-Cr composites were investigated with a focus on the contribution of the composite strengthening mechanism. The results show that with the increase of Cr content and the decrease of Al2O3 content, the strength of the composites gradually decreases, and the plasticity and electrical conductivity are enhanced. Among them, the elongation of 1.1 Al2O3/Cu-0.3Cr composites was enhanced from 10% to 15% while the strength was not considerably reduced. The addition of Cr promotes grain growth and dynamic recrystallization, whereas Al2O3 particles enhance the aging precipitation response of Cr particles. The results of strength mechanism calculations show that the tensile strength of Al2O3/ Cu-Cr composites mainly consists of Orowan strengthening caused by Al2O3 particles and dislocation strengthening in cold rolled deformation, while the dislocation strengthening is weakened at higher Cr content.
10.1016-j.matdes.2025.113635	15	aging; strength; conductivity; electrical conductivity; electrical; mpa; treatment; strengthening; degrees; cu-; cold; precipitation; tensile strength; tensile; iacs	The effects of P, Si and Al elements on the microstructure, corrosion properties and antibacterial properties of copper-tin alloys were studied. The addition of Si and Al elements reduced the layer fault energy of Cu-Sn-P alloy, refined grain and increased twins. Cu-Sn-P-Si and Cu-Sn-P-Al alloys were prone to grain boundary stripping corrosion and twin corrosion, which promoted the release of copper ions and improved the antibacterial properties. Cu-Sn-P-Al alloy had the best antibacterial activity. These results provide theoretical guidance for the development of new antibacterial copper alloy materials by microalloying the corrosion and ion release behavior of copper alloys.
10.1016-j.matdes.2025.113742	-1		Currently, laser and electron beam powder bed fusion (L/E-PBF) are prevalent in metal additive manufacturing (AM), demonstrating exceptional potential for producing copper (Cu) alloy components indispensable for numerous aerospace, automotive, energy, and marine applications. However, despite groundbreaking advances in metal AM, Cu alloys remain underdeveloped. This comprehensive review highlights the unremitting efforts to develop superior and bespoke L/E-PBF Cu alloy parts. Initially, roadblocks to Cu alloy printability are identified, along with solutions to surmount them, followed by feedstock development in the context of L/E-PBF. An extensive process-induced defect analysis is presented to assess the impact of powder feedstock characteristics, process parameters, and heat treatments. Furthermore, the mechanical, electrical, corrosion, and tribological properties of L/E-PBF-fabricated Cu alloy parts are elaborated to elucidate the nexus among materialmicrostructure-performance. In addition, this review delves into various strengthening mechanisms, the significance of post-processing heat treatment in stabilising non-equilibrium microstructures, and its influence on the material-property space. The discussion then extends to the importance of modelling for comprehending complex melt pool dynamics. Finally, the review uncovers lacunas and presents critical future research aspects to boost the technological readiness of L/E-PBF Cu alloys/composites for accelerated adoption.
10.1016-j.matdes.2025.113826	14	strength; properties; conductivity; electrical; mechanical; cu-; grain; mpa; electrical conductivity; aging; precipitation; phase; mechanical properties; tensile; phases	This study explores high-power laser powder bed fusion (LPBF) processing of Cu-Cr-Zr alloy, focusing on its high strain rate dynamic mechanical response and microstructural evolution. The alloy undergoes significant strain hardening during dynamic impact loading, primarily attributed to intensified dislocation interactions and multiplication. This is accompanied by thermal softening induced by adiabatic heating, therefore improving strain accommodation. As the strain rate increases from 4400 s(-1) to 11300 s(-1), the ultimate compressive strength (UCS) enhances from 173 +/- 8 MPa to 489 +/- 14 MPa, demonstrating a high strain rate sensitivity (SRS) of similar to 1. Microstructural examinations reveal that higher strain rates intensify the occurrence of adiabatic shear bands (ASBs), leading to severe localized plastic deformation. These ASBs generate localized stress concentrations, which in turn accelerate crack initiation and propagation through pore formation and coalescence within the ASBs. Despite this severe plastic deformation, texture analysis indicates that the crystallographic texture remains largely stable which suggests that the deformation mechanism is primarily governed by dislocation motion and interaction, rather than by crystal structure reorientation. Overall, the alloy balances strain hardening and strain accommodation at high strain rates, making it well-suited for applications requiring strength and resilience under dynamic impacts.
10.1016-j.matdes.2025.113935	14	strength; properties; conductivity; electrical; mechanical; cu-; grain; mpa; electrical conductivity; aging; precipitation; phase; mechanical properties; tensile; phases	With the development of high-end integrated circuits toward higher integration and ultra-thin designs, the comprehensive performance requirements for Cu-Ni-Si alloys as lead frame materials continue to increase. In this paper, the microstructure of the alloy is optimized by adjusting the deformation and aging parameters during the two-stage rolling process to enhance its performance and reveal the underlying mechanism. It was found that the hardness and strength of the alloy were enhanced while the conductivity remained unchanged or even slightly improved. With an increase in two-stage rolling deformation, the dislocation density of the alloy increases, promoting the rapid precipitation of the second phase and a reduction in grain size. The improvement in strength is primarily attributed to the synergistic effects of dislocation strengthening, precipitation strengthening, and grain boundary strengthening. In addition, with an increase in deformation, the texture strength of Cube, S, and Copper gradually decreases, while that of Brass increases significantly. This texture transformation is positively correlated with the comprehensive properties of the alloy.
10.1016-j.matdes.2025.113948	14	strength; properties; conductivity; electrical; mechanical; cu-; grain; mpa; electrical conductivity; aging; precipitation; phase; mechanical properties; tensile; phases	Copper alloys, valued for their excellent electrical conductivity and mechanical properties, are widely applied in electronics, power systems, and related fields. However, the extensive diversity and compositional range of alloying elements pose substantial challenges in alloy design. To address this challenge, this study applied a machine learning approach: a Support Vector Regression (SVR) based composition-conductivity model was constructed to predict the impact of individual elements on the alloy's electrical conductivity. According to the prediction results, Zn element was added to Cu-0.4Cr-0.06Ti alloy. Through experimental validation, it was shown that adding 0.05 wt% Zn achieves an ultimate tensile strength of 507 MPa, an electrical conductivity of 79 % IACS, and an elongation of 23 %. Morphology characterization revealed the role of Zn in the alloy: Zn was present in the matrix as a substitutional solid solution, while Cr was present as an interstitial solid solution. The addition of Zn promoted Cr precipitation and accelerated the transformation of Cr-rich phases, altering the interface between the matrix and precipitates from coherent to incoherent, thus reducing lattice distortion. This adjustment in solute elements and interfacial relationships enhanced both electrical conductivity and strength, breaking through the inverted relationship between strength and conductivity of copper alloy Furthermore, this study demonstrated that machine learning-based composition optimization effectively guides experimental design, providing new insights for the development of high-performance copper alloys.
10.1016-j.matdes.2025.113949	14	strength; properties; conductivity; electrical; mechanical; cu-; grain; mpa; electrical conductivity; aging; precipitation; phase; mechanical properties; tensile; phases	Nanocrystalline Cu-Zr films with Zr content in the range of 0.3-2.7 at% were deposited by direct current magnetron sputter deposition. Effects of Zr alloying on the structure, surface, mechanical, and electrical properties were systematically investigated using X-ray diffraction, electron microscopy, atomic force microscopy, indentation, and the four-point probe method. The experimental results revealed that the Zr content significantly affects the structural and functional characteristics of the films, with the most notable changes observed between 0.3 and approximate to 1.5 at% Zr. Beyond this range, further increase in the Zr content results in only minor changes in the microstructure and mechanical properties, while the solubility, electrical resistivity, and surface roughness continue to rise. The alloyed Cu-Zr films exhibit hardness values between 3.2 and 4.2 GPa, exceeding 2.5 GPa measured for the unalloyed Cu film, which is attributed to the combined effect of grain boundary strengthening due to structural refinement and Zr segregation, along with solid solution strengthening.
10.1016-j.matdes.2025.114007	-1		The segregation of trace elements is a central issue in casting large size ingots of precipitation-strengthening alloys. In this study, we introduced a pre-solution treatment into the hot-compression bonding (HCB) method for successfully additive fabricating homogeneous Cu-0.8Cr alloy specimen. The distribution of second phase and its influence on the interfacial bonding was systematically examined. The results indicate that with an optimized solution treatment time of 2 h at 1000 degrees C, the average size and number of the primary Cr particles near the interface were decreased to 0.58 mu m and 79 particles/mm2, respectively. Under this condition, the interfacial grain boundary migration during the HCB process was facilitated, and the dynamic recrystallization behavior transformed from continuous dynamic recrystallization to discontinuous dynamic recrystallization. Therefore, the interfacial tensile-shear strength and elongations reached 284.6 MPa and 4.71 mm, with recovery rates of interfacial strength and plasticity at 98.7 % and 100.6 %, respectively. The interfacial properties of HCBed Cu0.8Cr alloy were very close to the as-cast specimens, indicating that the additive homogeneous specimens could be further applied in forging process as the castings.
10.1016-j.matdes.2025.114009	14	strength; properties; conductivity; electrical; mechanical; cu-; grain; mpa; electrical conductivity; aging; precipitation; phase; mechanical properties; tensile; phases	Although copper alloys exhibit high electrical conductivity, their inherent low hardness and insufficient wear resistance significantly limit their application in high-energy current-carrying friction scenarios. This study leverages the liquid-liquid phase separation (LLPS) characteristics of immiscible alloys during non-equilibrium solidification and employs laser cladding technology to fabricate Cu-36Cr-xW-4SiC (x = 0, 2, 5, 10 wt%) composite coatings on CuCrZr alloy. The research systematically investigated the influence of tungsten content on the heterogeneous microstructure and the regulation of electrical conductivity-wear properties of the coatings. The results indicate that the introduction of 2 wt% W suppresses the Stokes migration effect of the second phase in the molten pool, promoting the periodic layered distribution of Cr-rich hard phase regions along the edges of the molten pool. This forms a hardness gradient up to 12 times higher than the Cu-rich soft phase regions. This heterogeneous structure achieves decoupled optimization of conductivity (35.8 % IACS) and wear resistance (average volumetric wear rate of 0.158 mm3/km, an 88.5 % reduction compared to the substrate) through a synergistic mechanism of hard phase bearing wear load-soft phase maintaining conductive pathways. The design strategy proposed in this study provides a new paradigm for the development of high-performance copper-based coatings.
10.1016-j.matdes.2025.114163	14	strength; properties; conductivity; electrical; mechanical; cu-; grain; mpa; electrical conductivity; aging; precipitation; phase; mechanical properties; tensile; phases	An investigation into the impact of varying Cr levels on the kappa phase, grain dimensions, and mechanical properties of the Cu-7Ni-7Al-4Fe-2Mn alloy was carried out using optical microscopy (OM), scanning electron microscopy (SEM), transmission electron microscopy (TEM), and an electronic tensile tester. It was discussed how Cr exists in the kappa phase and the mechanism of the strengthening properties. As the Cr content increases, Cr progressively substitutes for Al in the Fe3Al phase. Concurrently, the Fe3Cr phase tends to change from the D03 structure to the γ′ structure. In addition, as the Cr content increases, the size of the kappa IV phase and the kappa III phase in the alloy also changes to a certain extent, and when the Cr content increases to 1.2 wt%, the kappa III phase appears core-shell structure. The strength and hardness of the alloy initially increase with the rise in Cr content, followed by a subsequent decrease. An optimal comprehensive performance is observed when the Cr content is 0.6 wt%, at which point an excellent combination of strength and ductility of the alloy is achieved.
10.1016-j.matdes.2025.114190	-1		Laser directed energy deposited (L-DEDed) Cu alloys present substantial advantages for manufacturing thermal management devices without potential constraints on size. Herein, the printability, microstructure, and properties of a L-DEDed Cu-Cr-Zr alloy were investigated. Decreased scanning velocity facilitates the manufacture of single-track deposit with continuous and smooth surface morphology owning to the diminished Marangoni effect caused by a lower temperature gradient. A heterogeneous grain structure, characterized by an alternating distribution of equiaxed and columnar grains, was achieved in the thin-walled deposit, while a fully columnar grain was obtained in the bulk deposit. Under the effect of thermal cycling, numerous secondary Cr phase in-situ precipitated, and a small proportion of nano-sized annealing twins appeared in both the thin-walled and bulk deposits. In comparison, benefiting from nanotwins and more significant dispersion strengthening from secondary Cr precipitates, the thin-walled deposit exhibited a superior balance of tensile strength (similar to 337 MPa) and conductivity (similar to 63.6 % IACS).
10.1016-j.matdes.2025.114286	-1		As an essential part of continuous casting, Cu-Cr-Zr alloy molds are susceptible to cracking due to molten steel erosion, stress corrosion, and fatigue failure caused by high-temperature gradient, posing significant challenges to repair efforts. Here, Cu-Cr-Zr alloy plates with 2 mm in-depth and 1 mm in-width cracks were repaired via friction stir processing (FSP) and aging treatment. Dense and homogeneous microstructure and ultrafine grains with an average grain size of 0.55 mu m of the repaired zone (RZ) allowed for strong grain refinement against the coarse grains in base metal (BM). The nanoscale coherent precipitates induced by aging treatment exhibited precipitation strengthening, compensating for the loss of mechanical properties due to precipitate dissolution and coarsening during FSP. The microhardness, ultimate tensile strength, and the wear rate of the FSP + aged RZ were 146 HV, 456 MPa, and 5.81 mm3N- 1m- 1, respectively, closely reaching the mechanical properties of the BM. This work provides a promising, high-efficiency, and economical procedure for repairing cracks or other defects in Cu-Cr-Zr alloy.
10.1016-j.matdes.2025.114296	-1		Precise control of Fe-rich particles in Cu-Fe-Si alloy system is crucial for achieving balanced multi-properties such as electromagnetic and processability. Previous studies have reported that the morphology of Fe-rich particles formed during solidification is significantly influenced by the Si content. However, a detailed analysis of the underlying mechanisms remains insufficient. In this study, we carefully investigate the effect of adding 1.0-2.3 wt% Si on the Fe-rich precipitation behavior in a Cu-10 wt% Fe immiscible alloy through in-depth thermodynamic calculations, thermal analysis, and microstructural analysis. When the 1.0 wt% Si is added, dendritic particles form due to crystal orientation and interfacial energy. When 1.4 wt% Si is added, the Liquid-Liquid Phase Separation (LLPS) stabilizes, leading to Cu-Fe phase separation in the liquid state and the formation of spherical particles with a unimodal distribution. When Si exceeds 1.4 wt%, large Delta TLL_Fe (difference between LLPS onset temperature and Fe precipitation onset temperature), inducing hydrodynamic Brownian motion and Ostwald ripening, result in a diverse and uneven Bimodal or Trimodal distribution of Fe-rich particles with irregular morphologies. Consequently, the occurrence of stable LLPS and narrow Delta TLL_Fe during solidification has been identified as key factors in controlling particle morphology and distribution, and a threshold of Delta TLL_Fe <= 86 K is proposed to achieve uniform distribution of spherical 2nd phase particle in Cu-10 wt% FeSi alloys. This criterion provides a useful design guideline for precisely controlling the morphology and distribution of Fe-rich particles in the Cu-Fe-Si alloy system, which can be widely extended to other immiscible multicomponent alloy systems.
10.1016-j.matdes.2025.114329	14	strength; properties; conductivity; electrical; mechanical; cu-; grain; mpa; electrical conductivity; aging; precipitation; phase; mechanical properties; tensile; phases	Copper-steel functionally graded materials combine the thermal conductivity of copper with the mechanical strength of steel. This study examines the microstructural, mechanical, and thermophysical properties of the constitutive layers of copper-4130 steel functionally graded material fabricated via laser directed energy deposition, considering four intermediate compositions: 100% 4130, 75% 4130-25% Cu, 50% 4130-50% Cu, and 25% 4130-75% Cu. It was observed that the amount of Cu-rich terminal liquid governs crack formation and backfilling during solidification, while Cu-Fe liquid phase separation and Marangoni convection within the melt pool generate macrostructures composed of alternating Cu- and Fe-rich phases. Increasing Cu content progressively enhances thermal diffusivity due to the formation of interconnected copper regions. The application of quenching and tempering treatments induced softening of Cu-containing samples due to Cu recrystallization and diffusion from supersaturated Fe-rich phases. Although solidification cracking was only observed in 75% 4130-25% individual samples, the analysis of a complete multilayer structure revealed that interlayer mixing causes local compositional variations, extending cracking susceptibility beyond this region. These findings provide insights into the key factors governing laser directed energy deposition of copper-steel functionally graded materials, supporting process optimization and predictive model development to enhance manufacturability.
10.1016-j.matdes.2025.114365	14	strength; properties; conductivity; electrical; mechanical; cu-; grain; mpa; electrical conductivity; aging; precipitation; phase; mechanical properties; tensile; phases	The low strength of high-conductivity Cu-Cr-Zr alloys has restricted their application in micro-structural lead frames. This study introduces pre-aging multi-stage rolling processes to generate high-density dislocations via pre-precipitated Cr phases in a Cu-Cr-Zr-Ni-Si alloy, enhancing its hardening effect. The results show that the alloy processed by this thermomechanical treatment achieves an excellent combination of strength and conductivity: a tensile strength of similar to 680 MPa and electrical conductivity near 70 % IACS. Pre-aging modifies the geometric features of Cr precipitates, promoting strong interactions with dislocations during subsequent cold rolling. Hardening model calculations indicate that the alloy's reinforcement stems from the dislocation density strengthening and precipitation hardening. This work demonstrates that the pre-aging multi-stage rolling process can produce materials with superior comprehensive properties, holding promise for large-scale industrial applications of high-strength, high-conductivity copper alloys.
10.1016-j.matdes.2025.114549	14	strength; properties; conductivity; electrical; mechanical; cu-; grain; mpa; electrical conductivity; aging; precipitation; phase; mechanical properties; tensile; phases	In this study, micropillar specimens were fabricated using focused ion beam (FIB) milling. The mechanical properties of these micropillars were systematically investigated through a combined approach incorporating in situ transmission electron microscopy (TEM) compression testing, scanning electron microscopy (SEM) observations, and molecular dynamics (MD) simulations under varying strain rate conditions. Our experimental results demonstrate that the deformation behavior is strongly strain-rate dependent: at high strain rates, the micropillars predominantly form small, randomly oriented shear zones, whereas at lower strain rates, they exhibit more uniform and elongated shear zones patterns accompanied by enhanced plastic deformation. Through atomic-scale MD simulations, we have elucidated the fundamental mechanisms underlying shear zones formation and evolution. These findings provide valuable insights into the strain-rate dependent deformation mechanisms of amorphous alloys and offer potential strategies for enhancing their plasticity through strain rate control.
10.1016-j.matdes.2025.114915	14	strength; properties; conductivity; electrical; mechanical; cu-; grain; mpa; electrical conductivity; aging; precipitation; phase; mechanical properties; tensile; phases	The Cu-Ni-Si-Ti alloys with micron Ni16Ti6Si7 phase and nano delta-Ni2Si dual-scale reinforcement particles were prepared and their microstructures, properties as well as strengthening mechanism were studied. It is found that micron-sized Ni16Ti6Si7 particles (similar to 8 mu m) formed during alloy solidification, along with submicron Ni16Ti6Si7 and Ni2Si precipitates (similar to 200 nm). This behavior differed from that observed in conventional Cu-Ni-Si alloys. After heat treatment, the micron and submicron Ni16Ti6Si7 particles form semi-coherent interfaces with the alpha-Cu matrix, promoting recrystallization nucleation during hot rolling and thereby effectively refining the grain size of the alloy. Meanwhile, the nanoscale Ni2Si precipitates (similar to 30 nm) act as the primary strengthening phase, pinning grain boundaries and dislocations during deformation. Due to the significant elasticity modulus mismatch between Cu matrix and Ni16Ti6Si7 phase, a large strain gradient during the tensile process will lead to HDI strengthening, and improve the overall performance of the material through the storage and induction of dislocations at the Cu grain boundaries and the Ni16Ti6Si7-Ni2Si/Cu interface. Therefore, compared with Cu-3.2Ni-0.7Si alloy, Cu-4Ni-0.9Si-0.5Ti alloy exhibits higher elastoplasticity while maintaining similar strength and conductivity. Its peak-aged conductivity reaches 35.0 +/- 0 %IACS, with elastic modulus of 142 +/- 4GPa, tensile strength of 747 +/- 7 MPa, and elongation of 12.1 +/- 0.3 %.
10.1016-j.materresbull.2011.11.004	-1		This study focuses on the fabrication, for power electronics applications, of adaptive heat sink material using copper alloys/carbon fibers (CF) composites. In order to obtain composite material with good thermal conductivity and a coefficient of thermal expansion close to the ceramic substrate, it is necessary to have a strong matrix/reinforcement bond. Since there is no reaction between copper and carbon, a carbide element (chromium or boron) is added to the copper matrix to create a strong chemical bond. Composite materials (Cu-B/CF and Cu-Cr/CF) have been produced by a powder metallurgy process followed by an annealing treatment in order to create the carbide at the interphase. Chemical (Electron Probe Micro-Analysis, Auger Electron Spectroscopy) and microstructural (Scanning and Transmission Electron Microscopies) techniques were used to study the location of the alloying element and the carbide formation before and after diffusion. Finally, the thermo-mechanical properties have been measured and a promising composite material with a coefficient of thermal expansion 25% lower than a classic copper/carbon heat sink has been obtained.
10.1016-j.matlet.2004.05.082	-1		Solution combustion synthesis has been used for the preparation of finely dispersed copper oxide, copper and copper-nickel bimetallic particles. The structure and morphology of the materials are studied by XRD and SEM techniques. The fuel content in the combustion mixture is found to be a crucial factor in controlling the formation of oxide and metal particles. Starting with copper nitrate trihydrate as oxidizer (O) and carbohydrazide as fuel (F), we obtained CuO (F/O=0.75-1), mixed valence copper oxides, CuO+Cu2O, (F/O=1.0-1.5) and metallic Cu (F/O=2). At very low fuel content (F/O=0.5), a polymeric phase of copper hydroxide nitrate is isolated from the combustion residue. We also report the use of a new organic fuel N-tertiarybutoxy-carbonylpiperazine for the preparation of Cu, Ni and CuNi bimetallic particles.
10.1016-j.matlet.2004.07.031	-1		The study is centred on the microstructure evolution in Cu-3 vol.% of MgO composite during the preparation of a nanocrystalline powder and its processing into a macroscopic compact and thermal loading. The effect of dispersed oxide phase on the preservation of the initial nanostructure is analysed. Due to the weak coherency of the Cu/MgO interface, the Cu matrix is not sufficiently controlled by the MgO during heating. Some portions of the oxide nanoparticles agglomerate into coarser particles (>50 nm), which are less efficient barrier against the grain growth . Fine particles retard the grain growth . The consolidation results in a bimodal grain size distribution with micrometre-sized grains embedded inside a matrix of nanocrystalline/ultrafine grains. The fine, dispersion-strengthened grains provide good strength, as expected from an extrapolation of the Hall-Petch relationship. The inhomogeneous microstructure induces strain-hardening mechanisms that stabilize tensile deformation, leading to high tensile ductility.
10.1016-j.matlet.2004.08.014	-1		The Cu-12 wt% Ag Microcomposite was prepared and the influence of final annealing temperature on the microstructure, mechanical properties and conductivity were investigated. The recrystallization at temperatures lower than 300 degreesC occurs only within the fibrous phases. The strength, hardness and conductivity notably change with annealing temperatures at 200-400 degreesC. The fibrous structure annealed at lower temperatures maintains higher strength but lower conductivity. The equiaxial structure formed at higher annealing temperatures shows higher conductivity but lower strength . An optimal combination of the strength and conductivity can be obtained by annealing at 300 degreesC to induce recrystallizing and retain still the filamentary morphology formed in the strong drawing.
10.1016-j.matlet.2004.11.016	16	wear; composite; composites; powders; milling; particles; powder; wt; sliding; friction; hardness; matrix; mechanical; surface; properties	In this work. the effects of Fe, Mn and P elements on the wear resistance of Cu-Sn-Zn-Pb bronzes have been experimental investigated. For this aim, the test specimens have been produced as cast bronze alloys and whom Fe, Mn and P elements were added immediately. The produced samples have then been submitted to adhesive wear resistance tests. The wear resistance of specimens have been determined as a function between weight loss and sliding distance. The samples containing P elements showed the best abrasive wear resistance. But Fe and Mn elements reduced wear resistance of bronzes because of the existence of intermetallic compounds.
10.1016-j.matlet.2005.04.059	-1		The temperature spectra of internal friction and relative dynamic modulus of a Cu-11.9Al-2.5Mn (wt%) alloy were examined in the present study. A relaxational internal friction peak was observed at around 350 degrees C during the first heating process of the quenched specimens. However, the peak became invisible during the second or more heating process because it was overlapped by an even high IF peak or reverse MT peak at almost the same location. Nevertheless, it always appeared during the cooling process. Its activation energy was calculated to be 1.85 +/- 0.17 eV in terms of the Arrhenius relation. The operative mechanism of the peak was proved to originate from the Zener relaxation.
10.1016-j.matlet.2005.12.065	2	corrosion; surface; film; electrochemical; films; spectroscopy; layer; current; solution; potential; resistance; composition; x-ray; ions; showed	The preparation of nanocrystalline Cu-Ni alloy films by pulsed electrodeposition process and their structural, morphology, thermal characteristics and magnetic properties are addressed. The study reveals that the film composition, lattice constant and magnetic properties of the films could be controlled by the applied current density and duty cycle. Energy dispersive X-ray analysis (EDX) confirms that the Cu-Ni alloy film has a stoichiometry of Cu0.98Ni0.02, Cu0.95Ni0.05, Cu0.89Ni0.11, Cu0.77Ni0.23, Cu0.56Ni0.44 and Cu0.38Ni0.62 that are obtained at 2.5, 5, 7.5, 10, 15 and 20 A/dm(2), respectively. The X-ray diffraction (XRD) measurements confirm that all the six Cu-Ni alloy films of the present study possess the f.c.c. structure. The lattice constant is found to decrease with increase in nickel content of the Cu-Ni alloy. The crystallite size lies in the range of 15 to 46 nm for as-plated alloys and increases from 20 to 114 nm, following vacuum annealing at 400 degrees C for 1 h . The differential scanning calorimetry (DSC) trace indicates a broad exothermic peak characteristic of nanocrystalline materials. The vibrating sample magnetometer (VSM) study reveals that, among the six types of Cu-Ni alloy films, the films obtained at 2.5 and 5.0 A/dm(2) are diamagnetic; the one obtained at 7.5 A/dm(2) is weakly ferromagnetic, whereas those obtained at 10, 15 and 20 A/dm(2) are ferromagnetic. The saturation magnetization increases with increase in nickel content of the Cu-Ni alloy film.
10.1016-j.matlet.2006.03.103	-1		Experimental investigations on the development of the WC-10%Co particulate reinforcing Cu matrix composite material have been conducted using direct laser sintering. The chemical compositions and microstructures of the laser processed material have been characterized using X-ray diffraction (XRD), energy disperse X-ray (EDX) spectroscopy, scanning electron microscopy (SEM), and atomic force microscope (AFM). An excellent interfacial bonding between the reinforcement and the matrix was obtained. The WC reinforcing particulates typically had two distinct morphologies, i.e., partially dissolved and smoothed or completely dissolved and refined. The effects of the WC-Co content on the microstructural characteristics and resultant properties of the laser sintered parts have been studied. It was found that lowering the amount of WC-Co resulted in the insufficient reinforcement, while at a higher amount of WC-Co the significant agglomeration of the WC reinforcing particulates occurred. A homogeneous sintered structure with a high average hardness of HV(0.1)384.6 was obtainable using 30 wt% WC-Co.
10.1016-j.matlet.2006.06.042	-1		The structure of the melt-spun CU60Zr30Ti10 metallic glass is investigated by anomalous small angle X-ray scattering (ASAXS). It is confirmed that the compositional segregation in the diameter range of 30-50 nm exists in the as-quenched state. ASAXS results have convincingly shown the aggregation of Cu atoms and the formation of Cu-rich domains in the amorphous matrix. The Cu-rich domains grow slightly with low growth rate below the glass transition temperature, while the sizes of these domains drastically increase with high growth rate in the supercooled liquid temperature region. The Cu-rich domains are presumed to be associated with nucleation for the primary crystallization process.
10.1016-j.matlet.2006.10.051	-1		The silicon carbide particles (SiCp) dispersion-strengthened copper matrix composites (Cu/SiCp) were fabricated by composite electroforming technology. The microstructure, tensile property and wear behavior of Cu/SiCp composites were investigated. The results showed that composites with different SiCp contents were obtained. The microstructure of the composite presented a uniform distribution of SiCp in the matrix and good interfacial integrity. The hardness, yield strength and rigidity of the composites increased with increasing SiCp content, but at the cost of ductility. Increasing SiCp content in the composite was not always beneficial to the ultimate tensile strength and wear resistance. The ultimate tensile strength increased with SiCp content increasing up to 16 vol.% and decreased as exceeding 16 vol.%, and the wear mass loss decreased with SiCp content increasing up to 21 vol.% and increased again as exceeding 21 vol.%.
10.1016-j.matlet.2007.07.018	-1		Age hardening behaviour has been studied in a hot rolled copper-alloyed high strength interstitial free steel. The steel can be hardened to the peak-ageing strength employing low temperature coiling without any additional processing step. The age hardening data has been analysed with the available models for age hardening. The validity of the models has been tested and discussed to understand the effect of temperature on the peak-ageing time and the shape of the age hardening curves.
10.1016-j.matlet.2007.10.027	-1		For matte tin-plated copper leadframes stored at 55 degrees C/85% relative humidity (RH) for 1800 h, nodule-shaped whiskers were observed on test samples without postbake treatment (WOPB), while no whiskers were observed on samples with postbake treatment (WPB). The WPB samples show a very regular layer of intermetallic compounds (IMCs) approximately 27% narrower than the same layer in the WOPB samples. The IMCs had two distinct layers divided into large-grains and fine-grains. The large-grain layers located on the Sn side grew before the fine-grain layers. The IMCs in the WOPB and WPB specimens were identified as CU6Sn5 (monoclinic) and eta-CU6.26Sn5 (hexagonal). (c) 2007 Published by Elsevier B. V.
10.1016-j.matlet.2008.01.057	-1		The effects of trace Zr on the fatigue behavior of Cu-6Ni-2Mn-2Sn-2Al alloy were studied through the initiation and growth behavior of a major crack. When stress amplitude was less than sigma(a)=350 MPa, the fatigue life of Zr-containing alloys was about 2 times larger than that of alloy without Zr. When sigma(a)=400 MPa, the effects of Zr addition on fatigue life disappeared. Increased fatigue life due to Zr addition resulted from an increase in crack initiation life and microcrack growth life. Zr addition generated strengthened grain boundaries (GBs) that developed from the precipitation of SnZr compounds. Strengthened GBs contributed to the increase in crack initiation life. The effects of Zr addition on fatigue behavior were discussed with relation to the behavior of microcracks.
10.1016-j.matlet.2008.01.102	-1		The corrosion behavior of mechanically alloyed Cu60Zr30Ti10 bulk metallic glass (BMG) in four different corrosive media was studied by the potentiodynamic method. The Cu60Zr30Ti10 BMG shows low corrosion current density and uniform corrosion in IN H2SO4, NaOH and HNO3 solutions. The Cu60Zr30Ti10 BMG specimen (consolidated at 746K under 1.2GPa) specimen exhibits most corrosion resistance in IN H2SO4. The formation of the oxide films and the nucleation and growth of pitting will be discussed in light of microstructural investigations.
10.1016-j.matlet.2008.01.118	-1		The micro structural evolution and the mechanism of recrystallization grain growth (GG) were studied during re-aging process in the Cu-Ni-Si alloy containing finely pre-aging delta-Ni2Si precipitates using computer simulations based on a diffuse-interface phase-field kinetic model, in which the temporal evolution of the spatially dependent field variables is determined by numerically solving the time-dependent Ginzburg-Landau (TDGL) equations for the structural variables. The results show that the finely dispersed pre-aging delta-Ni2Si particles exert a strong pinning effect on the recrystallization grain boundaries (GB). Initially the GG accords with the power growth law with n between 0.3 and 0.4, followed by a gradual transition to growth stagnation. The final grain size follows a Zener type relation < R >= 1.41 * (r/f(a)(0.49)), with r the radius and f(a) the area fraction of the particles. The simulation results are compared with theoretical relations and previous simulation results.
10.1016-j.matlet.2009.02.064	-1		A novel stress-induced martensitic phase transformation in an initial < 100 >/{100} B2-CuZr nanowire is reported for the first time in this letter. Such behavior is observed in a nanowire with cross-sectional dimensions of 19.44 x 19.44 angstrom(2) over a temperature range of 100-400 K and at a strain rate of 1 x 10(9) s(-1) using atomistic simulations. Phase transformation from an initial B2 phase to a BCT (Body-Centered-Tetragonal) phase is observed via nucleation and propagation of {100} twinning plane under high strain rate tensile deformation.
10.1016-j.matlet.2009.10.018	1	shape; memory; shape memory; damping; martensite; martensitic; damping capacity; transformation; capacity; strain; superelasticity; temperature; cu-al-mn; shape memory effect; effect	Cu-13.5Al-4Ni shape memory alloy (SMA) exhibits a beta(1)(DO(3))->beta(1)' (18R) internal friction peak with high damping capacity and elevated martensitic transformation temperature in a dynamic mechanical analysis tan delta cooling curve. When the specimen is isothermally maintained at peak temperature, the damping capacity decreases significantly and reaches a steady value. The inherent and intrinsic internal frictions of Cu-13.5Al-4Ni SMA are extremely low because the beta(1)' (18R) martensite has an ordered 9R structure with stacking faults rather than twinning with movable twin boundaries.
10.1016-j.matlet.2009.10.024	-1		An ion beam mixing experiment for Cu-Zr system was conducted and two supersaturated solid solutions were observed with compositions of 16 atom% Zr in Cu and 17 atom% Cu in Zr, respectively, which are much greater than almost nil found from the equilibrium phase diagram of Cu-Zr system. The observation indicates that Cu-Zr metallic glasses could possibly be obtained in composition range bounded by the two observed solid solubilities, i.e. 16-83 atom% Zr. Besides, a unique Cu65Zr35 metallic glass was obtained by ion beam mixing and its composition is very close to the so-called best composition referred in the literature.
10.1016-j.matlet.2009.11.045	2	corrosion; surface; film; electrochemical; films; spectroscopy; layer; current; solution; potential; resistance; composition; x-ray; ions; showed	Nanoscale Bi-Te particles with thermoelectric properties on copper substrate were investigated. The substrate was prepared by electroplating copper layer on a copper zinc alloy plate in a copper Sulfate solution. Electrodeposition of the Bi-Te alloy particles was then performed in a nitrate bath . The electrolyte is composed of 0.05 M bismuth nitrate and 0.01 M tellurium dioxide dissolved in 2.0 M HNO(3). Cyclic voltammetry and quartz microbalance tests associated with the electrodeposition process were conducted to show the mechanism and kinetics of the deposition. The morphology and compositional analysis of Bi-Te was obtained using scanning electron microscopy (SEM) and energy dispersive X-ray spectroscopy (EDS) respectively. The morphology analysis suggested that nanoscale Bi-Te particles were obtained and the EDS results indicated that the surface of the copper substrate contained Cu(2)O. The atomic ratio 1:1 for Bi:Te in the alloy, which is equivalent to the weight percentage of Bi:Te=62%:38% was confirmed from the data obtained.
10.1016-j.matlet.2009.11.065	2	corrosion; surface; film; electrochemical; films; spectroscopy; layer; current; solution; potential; resistance; composition; x-ray; ions; showed	Ultra-fine grained (UFG) bulk pure copper has been successfully fabricated by equal-channel angular pressing (ECAP), with the grain size about 380 nm after 8 passes. The potentiodynamic polarization results of the ECAP copper specimens tested in Hanks solution revealed that the corrosion current of UFG copper is higher than that of the coarse grained copper. The cupric ion release behaviors of UFG copper immersed in Hanks solution for 30 days only displayed a burst release during the first 3 days (in comparison to the 1-2 months for the conventional Cu) from 115 mu g/day to 12.5 mu g/day, after which the ion release remained constant and slow. During the immersion experiments. Cu2O was the only corrosion product found on the surface and it took 10 days or so to form a uniform Cu2O layer. Uniform corrosive damage on the surface and few localized corrosion is observed. The above results indicate that UFG copper could have high potential as biomedical materials for contraception.
10.1016-j.matlet.2009.12.047	-1		Based on Miedema's semi-empirical model, a Gibbs free energy diagram is constructed for the Cu-Hf system and shows that the amorphous phase is favored to be formed over 8-94 at% Hf, which is much broader than the experimentally determined 30-70 at% HE Three Cu-Hf multilayered films were therefore designed with the overall compositions of Cu93Hf7, Cu81Hf19 and Cu23Hf77, respectively, and then an ion beam mixing experiment was conducted using 200 keV xenon ions to see whether the metallic glass forming range of the Cu-Hf system Could be extended beyond the previously reported range. Interestingly, ion beam mixing results show that a uniform amorphous phase can be obtained in the Cu23Hf77 sample and the amorphous phase is also observed to coexist with crystalline Cu in the Cu81Hf19 sample. These results suggest that the metallic glass forming range of the Cu-Hf system could, at least, be extended to 77 at% HE which falls in the range predicted by the Gibbs free energy diagram.
10.1016-j.matlet.2010.01.015	2	corrosion; surface; film; electrochemical; films; spectroscopy; layer; current; solution; potential; resistance; composition; x-ray; ions; showed	Morphological and optical properties of as-grown copper tin sulfide layered materials have been investigated using an original analytical protocol. Conjoint Band gap-Roughness optimality has been obtained for the particular value of the copper-to-tin ratio chi(opt), = [Cu(2+)]/[Sn(2+)] = 3.27 approximately. Regarding the optical, thermal and mechanical constraints of the use of similar materials, precursor mixture parameters have to be chosen before optimal performances are reached. In this context, the obtained value of the optimal copper-to-tin ratio in the precursor solution is proposed. This value could be an efficient guide to understanding these materials' epitaxial growth-deposition kinetics and optimizing mechanical resistance to damage and fatigue.
10.1016-j.matlet.2011.03.034	-1		Bridgman-type directional solidification experiments have been carried out in Cu-20Sn peritectic alloy. Peritectic coupled growth and banding structures have been observed at low growth rates (1.5 and 2 mu m/s) under a temperature gradient up to 40 K/mm. The peritectic coupled growth structure, containing rod dendrite primary beta phase plus peritectic alpha phase, forms initially. As solidification proceeds, peritectic coupled growth is overgrown by banding or island banding structures. The formation of banding structure from coupled growth is explained by a model involving Sn concentration change at nucleation of the secondary phase ahead of the solid/liquid interface. It is found that the competitive growth between the alpha and beta phases also plays a critical role on the formation of banding structures.
10.1016-j.matlet.2012.03.117	-1		A carbon nanotube and copper composite was synthesized using electroless plating and freeze-drying for green processing, and spark plasma sintering for densification. A magnetic field of 1 T was applied during the freeze-drying process to align the carbon nanotubes along the main axis. Results show that the magnetization process enhanced the alignment and thermal conductivity properties of the final Cu-CNT product (up to 386% in one example), but the properties were lowered overall due to interfacial bonding and particle mixing difficulties, with the results being 5-15% of the thermal conductivity of pure copper.
10.1016-j.matlet.2012.10.100	-1		Cu13Zr40Al47 amorphous phase was obtained in the Cu-Zr-Al metallic system by 200 keV xenon ion beam mixing (IBM) in the irradiation range of 0.8 similar to 4 x 10(15) Xe+/cm(2), clarifying that Cu-Z-Al metallic glasses with high concentration of Al could be experimentally obtained. We also found the mixtures of amorphous and crystalline phases newly formed in the Cu7Zr14Al79, Cu16Zr7Al77, Cu27Zr22Al51 and Cu84Zr9Al7 multilayered films. The possible formation mechanism of these resultant alloys is discussed in terms of the atomic collision theory. These experimental results also provide a substantial support to the results of molecular dynamics simulation, which presents a theoretical prediction of metallic glass favored region.
10.1016-j.matlet.2012.11.102	-1		The influences of Zn doping on the relative stability of hexagonal and monoclinic Cu6Sn5 were investigated using a first-principles approach . It was found that the phase stability of monoclinic and hexagonal Cu6Sn5 could both be improved by Zn doping. For the monoclinic structure, Zn atoms preferentially occupied the 4e (Sn3) sites, it was 2c (Sn1c) sites for the hexagonal Cu6Sn5. The results of density of states demonstrated that hybridization of Zn-d and Sn-s state was the dominant factor for the stability improvement for both structures. Moreover, the Zn atoms concentration corresponding to the most stable structure for hexagonal Cu-6(Sn,Zn)(5) was 7.54%, which was consistent with the experimental results.
10.1016-j.matlet.2012.12.098	-1		Atomic structure of Cu37Sb63 and Cu20Sb80 melts has been studied by high temperature X-ray diffraction and viscosity measurement. Split main peaks indicate Cu-Sb heterogeneous and Sb-homogeneous clusters dominate in these two melts, respectively. This results in the smaller first-neighbor radius and higher viscosity in Cu37Sb63 melts. In pair distribution functions of Cu20Sb80 melts, the hump around 0.44 nm becomes obvious below 973 K, which reveals the reinforcement of Sb clusters with Peierls distortion. This is consistent with the increase in viscous-flow activation energy in Cu20Sb80 melts around 973 K. Structure parameters change is also discussed in terms of clusters evolution during cooling.
10.1016-j.matlet.2013.06.071	-1		The microstructure, crystallographic texture and magnetic properties have been studied in a Cu-33 at%Ni substrate produced by cold rolling to a reduction of similar to 99% with subsequent annealing at 1000 degrees C for 1 h in a protective atmosphere. This treatment results in a strongly textured material, where the fraction of the cube {001} <100> texture is 99.8% and the fraction of boundary misorientations with angles greater than 10 degrees is only 5%. The material is shown to be non-ferromagnetic at typical operating temperatures for coated conductors. Furthermore, it is shown that a CeO2 buffer layer can be successfully deposited on the Cu-33 at%Ni substrate using dip-coating.
10.1016-j.matlet.2014.02.025	-1		Open-cell foam of a Cu-Ni alloy integrated with graphene was used as a lightweight, multilayered, electromagnetic interference (EMI)-shielding material. It was prepared by electroless copper plating, then nickel electroplating, and finally electrophoretic deposition of a graphene nanosheet (GNS). The foamed Cu-Ni-GNS composite comprises, from the inside to the outside, Cu, Ni, and GNS layers. The morphology and EMI performance in the 8-12 GHz range were characterized and studied, respectively. The results indicate that the shielding effectiveness of the composite increased with increasing pore density (measured in pores per inch) and increasing thickness. The porous structure of the composite could attenuate the incident electromagnetic microwaves by reflecting, scattering, and absorbing them between the metallic skeleton and the GNS layer. This multilayered foamed composite is a potential material for applications in which shielding and ventilation are required.
10.1016-j.matlet.2014.02.050	-1		A grain coarsening behavior was reported in this work in nanocrystalline copper during sliding friction. The cross-sectional microstructure and micro-hardness of the pure copper subjected to sliding friction were investigated in detail. A nano-grained surface layer of copper was obtained after sliding against a WC-Co ball for the first 100 cycles. However, a pronounced grain coarsening was observed during the subsequent sliding cycles. Such a behavior is dominated by high stress, high strain as well as large amplitude adopted in sliding friction.
10.1016-j.matlet.2014.03.101	-1		Here, we report the synthesis of single crystalline beta phase Cu-Zn nanowires (diameter around 150 nm and typical length up to 10 mu m) by combining electrodeposition and annealing. The obtained nanowires present temperature driven martensitic transformation similar to that found in bulk samples from B2 to 9R structure. A weak influence of the dimensionality on the martensitic transformation is observed in these nanowires. The possibility to obtain bundles of single crystalline nanowires with tunable martensitic transformation temperature and hysteresis similar to that found in bulk, seems to be a fundamental approach to the development of smart nanosystems based on shape memory alloys.
10.1016-j.matlet.2014.09.046	-1		Two types of Cu-45 at%Ni alloy thin tapes with and without surface shear were obtained by different heavy cold rolling processes. The deformation and recrystallization textures of the two tapes were thoroughly investigated by electron back scattering diffraction technique. The results showed that a shear texture mainly covered the surface of the heavy deformed tapes because of the fraction between the surface of rolling mills and the thin tapes when the rolling force strongly reduced at high strain, which significantly reduced the fraction of rolling texture on the surface of the Cu-45at%Ni alloy thin tapes, retarded the cube grain growth during recrystallization and affected the strong cube texture formation after high temperature annealing. (C) 2014 Published by Elsevier B.V.
10.1016-j.matlet.2014.09.048	-1		Grain boundary triple junctions are defects in their own right with specific thermodynamic and kinetic properties. The line tension of a grain boundary triple junction will cause impurity segregation, which, in turn, affects the triple line energy and gives rise to a drag effect of solute atoms on grain boundary motion. This can strongly impact microstructural development, in particular of fine grained and nanocrystalline materials. We measured the line tension of grain boundary triple junctions which comprised the intersection of three random high angle boundaries in a Cu-Ni alloy (Ni content about 2.2%) to be 7.8 x 10(-9) J/m. This energy is slightly higher than the line tension of a comparable triple line in pure Cu.
10.1016-j.matlet.2015.05.076	-1		Highly-dense bulk Cu-10Sn bronze specimens have been fabricated by selective laser melting (SLM) and their (micro)structure and mechanical properties have been investigated and compared with the corresponding material produced by casting. Room-temperature tensile tests reveal that yield and ultimate strengths increase from 120 and 180 MPa for the cast samples to 220 and 420 MPa for the specimens processed by SLM. Material strengthening is accompanied by a significant improvement of ductility, which increases from 7 to 17%. This behavior can be ascribed to the refined microstructure of the SLM material resulting from the high cooling rate imposed by laser processing, further demonstrating the effectiveness of SLM for the production of materials with enhanced mechanical performance. (C) 2015 Published by Elsevier B.V.
10.1016-j.matlet.2015.05.150	6	grain; deformation; strain; strength; dislocation; cu-; tensile; size; ecap; grain size; sfe; ductility; hardening; high; stress	This article presents an application of cryogenic impact deformation in effective grain refinement in coarse-grained copper. Ultrafine-grained microstructure was processed by means of cryogenic impact deformation using an air hammer with an initial impact velocity of 7.35 m s(-1). For strain epsilon=2.21, TEM observation showed that the initial equiaxed coarse grains (18 mu m) evolved into a lamellar structure of submicron size narrow domains delineated by low-angle grain boundaries. The microhardness of the deformed sample increased from 74.2 +/- 1.2 HV to 118.3 +/- 1.8 HV. Subsequently annealed at 190 degrees C for 60 min led to a significant reduction of dislocation density. Elongated ultrafine grains (with a mean width of 175 nm) embedded with remaining nanoscale deformation twins were observed in the annealed sample. This study highlights the potential of cryogenic impact deformation to produce bulk ultrafine-grained materials.
10.1016-j.matlet.2015.10.165	12	thermodynamic; ternary; phase; data; experimental; equilibria; phase equilibria; liquid; binary; experimental data; calculated; phases; literature; model; calphad	Ternary Cu-Sn-Sb alloys are a good candidate for solder materials without Pb element. Therefore, the knowledge of thermodynamic properties and phase transition characteristics of this alloy system is essential not only for the fundamental research but also for the industry applications. In this letter, we have measured the liquidus and solidus temperatures, enthalpy of fusion and thermal diffusivity for ternary Cu90-xSnxSb10 alloys by differential scanning calorimetry (DSC) and laser flash methods, respectively. Moreover, the typical growth morphologies of various intermetallic compounds are characterized. It is found that the primary Cu3Sn, Cu6Sn5, Cu4Sn, Cu3Sb and SnSb phases display faceted growth mode, and develop into long strips or large blocks. By contrast, the primary (Cu) phase forms by non-faceted way into very coarse dendrites.
10.1016-j.matlet.2015.11.024	-1		A hierarchical trimodal structure comprised of micro-porous Gasar Cu, nano-porous Cu and nano-cellular cuprous oxide (Cu2O) was fabricated by dealloying Cu-Zn alloy layer on the inner surface of Gasar pores along with a spontaneous oxidation process. The influence of corrosion time on the microstructure of the resulting nano-porous Cu and nano-cellular Cu2O was investigated. Observed results showed that with the corrosion time increase, both of the structures were coarsened, and the nano-cellular Cu2O was further oxidized into nano-lamellar copper oxide (CuO).
10.1016-j.matlet.2016.02.138	0	solidification; phase; magnetic; magnetic field; undercooling; field; liquid; separation; peritectic; immiscible; cu-; dendrite; phase separation; microstructure; primary	The morphology evolution of iron-rich crystal in Cu melt has been investigated via Spherical-aberration corrected scanning transmission electron microscopy (Cs-corrected STEM). Morphology of iron-rich crystal was observed to transform from the stable sphere to petal-like unstable shape when the radius of the crystal increase to approximately 11 nm, which is in a good agreement with Mullins-Sekerka's instability theory. This work opens a new insight to understand nano crystal growth at initial solidification stage.
10.1016-j.matlet.2016.05.059	-1		The Cu-36 wt% Sn alloy was subjected to the high pressure torsion (HPT) at room temperature. Before deformation the microstructure was composed of alternating coarse-grained plates of the zeta and epsilon compounds (Hume-Rothery electronic phases). HPT led, as usual, to the strong grain refinement and increase of dislocation density. However, the macroscopic shape of zeta and epsilon plates remained unchanged. It means that the refinement took place in each phase individually, i.e. inside the respective zeta and epsilon plates. High angle grain boundaries are more pronounced ins phase. This unusual behavior of the alloy is connected with a high hardness of the zeta and epsilon intermetallic compounds.
10.1016-j.matlet.2016.05.064	-1		Cu-Cr-Zr-Ti alloy specimens have been fabricated by selective laser melting (SLM) technology with a high relative density. Their microstructure and mechanical properties at room conditions as related to elevated temperatures have been investigated after solution annealing and aging of the material and compared to hot-rolled samples. The microstructure of the SLM material consists of grains elongated along build direction with the size in the range from 30 to 250 mu m. The mechanical test showed that the SLM material has 195-211 MPa ultimate tensile strength (UTS) and 11-16% elongation at break at 20 degrees C. Samples produced parallel to the build direction show slightly higher UTS and elongation at break in comparison with samples fabricated perpendicular to the build direction. The UTS of the SLM samples is approximately 20-25% lower compared to the hot-rolled samples. The study revealed that SLM technology can be successfully utilized to produce complex-shaped copper alloy parts with high density and good mechanical properties.
10.1016-j.matlet.2016.09.020	6	grain; deformation; strain; strength; dislocation; cu-; tensile; size; ecap; grain size; sfe; ductility; hardening; high; stress	The mixture microstructures with nano/ultrafine grains in pure copper were prepared by using of cryogenic friction stir processing. The processed zone was mainly composed of ultrafine grains and more than 30% of nano-grains. The mechanical properties of the nano/ultrafine grain structured pure copper exhibited an enhanced ultimate tensile strength and high tensile elongation. It can be attributed to the mixed deformation mechanisms of grain boundary sliding, and the dislocation pile-up in the ultrafine grains with high-energy nonequilibrium boundaries.
10.1016-j.matlet.2016.10.077	-1		The structural evolution of nano Cu-precipitates was studied with high-resolution transmission electron microscopy. 9R Cu precipitates were mainly multiple-twinned. However, the unusual 9R Cu precipitates with no twins were also observed. The 9R -> face-centered tetragonal (fct) transition can occur without complete detwinning with 9R Cu structure, which has been confirmed by fast Fourier transform pattern and calculation of Moire' fringes. Instead of commonly-accepted evolution process of body-centered cubic (bcc)-> twinned 9R -> 3R -> face-centered cubic (fcc), a new transformation mechanism of bcc -> 9R -> twinned fcc or fct -> fcc has been proposed. Finally, a crystallographic model was established to explain the bcc -> 9R -> fcc transformation processes.
10.1016-j.matlet.2016.12.014	-1		We report the feasible fabrication of sodium borosilicate (NBS) glasses embedded with phase-controlled Cu-Ni nanostructures using a sol-gel route plus varying gas. Microstructural investigations demonstrate that the oxygen produce randomly distributed CuO-NiO nanostructures whereas upon reduction atmosphere Cu0.81Ni0.19 alloy nanostructure is generated in glass host. Interestingly, both of the two glasses exhibit effective reverse saturable absorption effect and self-focusing performance, presenting potential for use in nonlinear optical devices. Then, the mechanism on the nonlinear response is also discussed.
10.1016-j.matlet.2017.04.039	6	grain; deformation; strain; strength; dislocation; cu-; tensile; size; ecap; grain size; sfe; ductility; hardening; high; stress	The effect of Cr and Zr contents on the properties of ultra-fine grained (UFG) Cu-Cr-Zr alloys subjected to high-pressure torsion (HPT) was studied. It is found that increasing in chromium content above the solubility limit does not cause additional hardening both after HPT and after subsequent aging. In contrast, excessive alloying with zirconium allows obtaining a structure with a smaller grain size, enhances structure stability during heat treatment and noticeably increases strength with high electrical conductivity of the alloy after HPT and additional aging.
10.1016-j.matlet.2017.05.092	-1		In this study, the Cu66.5Zr33.5 (at%) metallic glass layers were deposited using laser melting additive manufacturing technique to investigate the effect of laser power on the deposition of CuZr metallic glass micro-wires. The Cu-based metallic glass micro-wires similar to 150 mu m in diameter with circular cross section were produced by melt-extraction method. It was found that the mean width of deposited layer is expanded from 166 mu m to 356 mu m with increasing laser power attributed to a change in the wettability. The micro-hardness value of Cu-based metallic glass deposited layer was higher in low power deposition. The reliability for the optimization of processing parameters to control micrometer scale deposition by metallic glass wire is also evaluated.
10.1016-j.matlet.2017.06.042	-1		In this work, boron spheres were successfully prepared in Cu alloy by a simple direct melt reaction method. Spherical boron can form in the Cu-B alloy cooled at a high cooling rate, and boron spheres can be obtained by the acid corrosion of metal Cu. The size of boron spheres extracted from Cu alloy can be controlled and changed from about 3 nm to several hundreds of nanometers. The boron spheres consist of loose disorder center and irregular layers outside. The aggregation of two boron spheres should follow twinning mechanism.
10.1016-j.matlet.2017.08.082	16	wear; composite; composites; powders; milling; particles; powder; wt; sliding; friction; hardness; matrix; mechanical; surface; properties	Mechanical alloying and uniaxial compaction were used to obtain configurations of: elemental powders of Cu and Ni; binary alloys (Cu-Ni and Cu-Zr); and a ternary alloy (Cu-Ni-Zr) under the same mechanical milling and hot pressing conditions. Microstructure and mechanical properties of these were investigated. According to XRD results, hot pressing process increases crystallite size and decreases microstrain in the compact samples, due to the release of crystalline defects without crystallization of amorphous alloys. The milled powder samples have a higher hardness than the unmilled samples, since crystal defects are incorporated into microstructural refinement during milling. The ternary alloy Cu-40Ni-10Zr had the highest hardness of all systems studied, reaching 689 HV0.5. Compression tests at 5% strain determined that Zr-containing samples (amorphous phase) become more fragile after processing, and have the lowest values of compressive strength . In contrast, Ni samples and Cu-Ni binary alloys are more resistant to compression.
10.1016-j.matlet.2017.08.123	4	transformation; martensite; martensitic; phase; shape; beta; memory; shape memory; temperature; temperatures; martensitic transformation; gamma; transformation temperatures; effect; thermal	The phenomenon of metallic grain ejection is for the first time explained. An evaluation of ejected grains was performed in Cu-Al-Ni shape memory alloy load-free cycled up to 500 times within the temperature interval of reversible martensitic transformation (RMT). An intergranular fracture mechanism related to RMT is proposed to this phenomenon. By image processing, 8 grains/cm(2) after 500 cycles were measured. This is attributed to gamma'(1) martensite transformation at the grain boundaries.
10.1016-j.matlet.2017.09.058	2	corrosion; surface; film; electrochemical; films; spectroscopy; layer; current; solution; potential; resistance; composition; x-ray; ions; showed	A novel approach of combining templated-assisted electrodeposition, and a subsequent dealloying/displacement reaction for fabricating Cu-Mo-Fe-Ni nanowire segments is introduced. Precursor Fe-Mo-Ni nanowires were electrodeposited from a citrate-boric acid electrolyte using a polycarbonate template with pulse potential deposition. The embedded wires were dipped into an acid, copper citrate electrolyte to promote dealloying/displacement reactions to generate polycrystalline Cu-Mo-Fe-Ni segments.
10.1016-j.matlet.2017.10.077	-1		Ball milling (BM) a Cu nanopowder resulted in an increase of the average grain size from 8 to 52 nm, followed by a gradual decrease to 19 nm. In contrast, the grain size of coarse-grained Cu decreased monotonically from 290 nm to 19 nm. Fitting a model to the kinetic curves indicates that the two processes have similar activated volumes during collisions. It also reveals that particles over 100 nm are formed when nanoparticles are compressed during a collision for the first time.
10.1016-j.matlet.2017.12.009	-1		A combination of high tensile strength of 900 MPa and a good electrical conductivity of 50% International Annealed Copper Standard (IACS) was achieved in a nanocrystalline Cu-0.1 wt% Al (grain size: 96 nm) matrix composite reinforced with 6.4 vol% NbC nanoparticles (6.5 nm). The composite was produced by combining high energy mechanical milling (HEMM), sintering and powder compact extrusion. The composite was highly thermally stable that a higher electrical conductivity of 57% IACS was achieved, while maintaining a high tensile strength of 722 MPa and good ductility after annealing at 1000 degrees C for 5 h .
10.1016-j.matlet.2018.03.194	16	wear; composite; composites; powders; milling; particles; powder; wt; sliding; friction; hardness; matrix; mechanical; surface; properties	Additive manufacturing by selective electron beam melting (SEBM) was used to process a powder mixture consisting of elemental copper and chromium powders (nominal composition: Cu-25Cr). The melting temperatures of copper and chromium are largely different. As a result, the copper particles start melting while the chromium ones are still solid. Eventually, also the chromium particles get molten since the local temperatures during SEBM are rather high . The microstructure was analyzed by scanning electron microscopy (SEM) and focused ion beam (FIB)-SEM. It was observed that ultra-fine Cr particles are formed and distributed in the Cu matrix due to the fast cooling rate and subsequent spinodal decomposition. (C) 2018 Published by Elsevier B.V.
10.1016-j.matlet.2018.05.008	4	transformation; martensite; martensitic; phase; shape; beta; memory; shape memory; temperature; temperatures; martensitic transformation; gamma; transformation temperatures; effect; thermal	Cu-Al-Ni and Cu-Al-Ni-Mn shape memory alloys are deposited on Kapton polyimide sheets by a physical evaporation technique. Detailed investigations on the morphological, structural and thermal behaviour of the ternary and quaternary alloys are conducted. The developed samples exhibit an increase in martensite structures and decrease in transformation temperatures after Mn additions. Furthermore, the suppression of Cu 3 Al precipitates was evident from XRD analysis. The thermomechanical behaviour was analysed by actuating the bimorphs through Joule heating under varying mechanical loads. Fatigue analysis of the bimorphs reveals a superior performance for Cu-Al-Ni-Mn, exhibiting less than 30% loss in displacement after 15,000 cycles.
10.1016-j.matlet.2018.07.028	-1		Cu wires can be significantly strengthened without losing much conductivity if a continuous nanolamellar structure with Cu and a strong second constituent is achieved. We report on a nanolamellar Cu/steel wire fabricated by repetitive hot-pressing, forging, rolling and subsequent wire drawing. Austenization and quenching in liquid nitrogen resulted in a Cu/martensite structure, exhibiting tensile strength of 1220 MPa. The electrical conductivity of the wire was measured to be about 60% International Annealed Copper Standard (IACS), which was comparable with Cu/Fe fabricated by alloying and casting. In situ tensile tests under high energy X-ray diffraction were utilized to explore the deformation behavior of the wire. It was found that the martensite carried about 60% of the load, accounting for the high strength .
10.1016-j.matlet.2018.08.071	-1		This study examines the rate of grain size reduction as a function of the volume of Cu powder subjected to ball milling and ball drop experiments at constant impact energy. For volumes between 1.6 x 10 (3) and 3 cm(3), the grain size decreases exponentially from about 300 to 19 nm and the rate constant is inversely proportional to the volume of powder. This suggests that the volume of powder undergoing grain size reduction in a given impact is approximately the same, about 7.4 x 10 (7) cm(3), for ball milling and ball drop experiments and it is independent of the total volume of the powder.
10.1016-j.matlet.2018.09.158	-1		The method utilizing high-pressure torsion (HPT) processing followed by annealing to fabricate Cu-Al in situ composite with enhanced mechanical properties is presented. The initial sample consists of three metal discs Cu/Al/Cu was processed by HPT (5 GPa, 5 turns). The analyses of the microstructure after HPT carried out by transmission electron microscopy and scanning electron microscopy equipped with energy dispersive spectrometry (EDS). After HPT, the development of nanostructure with the mean crystallite size of about 100 nm in the produced sample was revealed with the small presence of the intermetallic phases. Investigation of the kinetics during subsequent annealing at 450 degrees C/30 min showed the in situ formation of intermetallic Al2Cu, AlCu, Al3Cu4, Al2Cu3 and Al4Cu9 phases in the copper matrix which was detected by EDS. The formation of intermetallic phases after annealing was also confirmed by X-ray diffraction. The results showed that microhardness of the composite considerably increases from an initial value of similar to 380 for HPT sample to a saturation value of similar to 900 after annealing.
10.1016-j.matlet.2018.10.128	-1		Secondary phases precipitating after aging treatment in Cu-Ni-Si alloy will influence the texture of the copper alloy. The texture and the second phase characteristics under different aging processes were investigated. The results show that the strength of copper texture {2 1 1} < 1 1 1 > and Goss texture {0 1 1} < 1 0 0 > decreases gradually and the strength of cubic texture {0 0 1} < 1 0 0 > increases when the aging temperature increases. The second phase Ni2Si gradually accumulates as the aging temperature rises, mainly in spheres and squares, and influences the strength of the texture through the effect on distortion of the surrounding area.
10.1016-j.matlet.2018.11.034	-1		The present study, for the first time, revealed the athermal recrystallization behavior at a heterogeneous metallic interface using room temperature electromigration. The athermal recrystallization occurred within the meta-stable amorphous Cu-Sn interphase, which was formed during the early stage electromigration, for stress relaxation after further electromigration. The nano-scale polycrystalline (Sn) interphase was favorably recrystallized at the intermetallic-free Cu/Sn interface where the current crowding effect occurred. Athermal electromigration force facilitated the nucleation of Sn nuclei through the kinetic energy provided by the electron momentum transfer. The formation of the recrystallized (Sn) interphase is believed to be an intermediate material interaction product prior to further intermetallic nucleation under room temperature electromigration.
10.1016-j.matlet.2018.11.108	-1		A nanostructured surface layer of similar to 300 mu m thickness was fabricated on Cu-30Cr (wt%) hypereutectic alloy by a continuous laser beam with high power density (1.08 x 10(7) W/cm(2)). The average grain size of Cr-rich particles was refined to similar to 40 nm, and the solid solubility limit of Cr in Cu was extended to 1.96 at. %. Experimental results show that the dispersion of nano-sized Cr-rich spheroids in Cu-rich matrix was attributed to the Brownian motion of Cr-rich spheroids, and the high cooling rate (5.75 x 10(6) K/s) during liquid phase separation which inhibits the collisions between Cr-rich spheroids. (C) 2018 Published by Elsevier B.V.
10.1016-j.matlet.2018.11.118	15	aging; strength; conductivity; electrical conductivity; electrical; mpa; treatment; strengthening; degrees; cu-; cold; precipitation; tensile strength; tensile; iacs	Although different kinds of metal materials have been built in the past years, it is difficult to fabricate the components of copper alloys with high strength and high conductivity due to their high reflectivity and thermal conductivity. In this paper, Cu-Cr alloy with high strength and high conductivity was successfully manufactured by high laser power selective laser melting. The microstructure, mechanical properties and conductivity were studied and compared before and after the heat treatment. The microstructure of the as-built sample was columnar grains with very fine cellular sub-structures and precipitates of Cr and Cr2O3. After heat treatment, the Cr particles precipitated from Cu matrix, resulting in simultaneous increase in strength and conductivity. The ultimate tensile strength of 468 MPa, yield strength of 377.33 MPa, and electrical conductivity of 98.31% IACS were achieved, which is even better than the samples fabricated by rolling with post heat treatment.
10.1016-j.matlet.2018.12.142	4	transformation; martensite; martensitic; phase; shape; beta; memory; shape memory; temperature; temperatures; martensitic transformation; gamma; transformation temperatures; effect; thermal	Cu-Al-Ni shape memory alloys have good thermal stability and shape memory properties, but mechanical working of these alloys is very difficult due to inter-granular fracture and brittleness. This paper deals with improvement of shape memory properties and ductility of these alloys with the addition of boron. It was observed that with addition of boron in a designed experiment, ductility improved by more than four times than that of the base alloy. In addition, shape memory properties also improved significantly. These results obtained are discussed in this paper systematically.
10.1016-j.matlet.2019.07.018	-1		CNTs/Cu-Al2O3 composite powders were successfully synthesized by in situ CVD using Cu-Al2O3 composite powders obtained by internal oxidation of Cu-Al alloy powders. The multi-walled CNTs are obtained without agglomeration and stand on the surface of the composite powders. One end of the CNTs is well bound to matrix. The Cu nanoparticle was the catalyst for the growth of CNTs on the composite powders and Al2O3 on the surface of the Cu-Al2O3 powder plays a key role in the growth process.
10.1016-j.matlet.2019.126525	-1		Sn grain boundary diffusion (GBD) in dilute (up to 2% at Sn) Cu-based alloys was investigated in the temperature range from 560 to 650 degrees C by the EPMA method. 3-layer samples Cu/Cu-Sn alloy/Cu were prepared. Experimental values of the triple product P = s delta D-b were obtained in the frame of Fisher-Gibbs model: P= 10(-13).exp(-89 kJ/mol/RT) m(3) s(-1). The effective activation energy comprises approximately 0.5 from the bulk value. In the chosen temperature range the path of the bulk diffusion was equal about 10 mu m and the path of GBD (Fisher length) varied in the range 20-30 mu m. The accelerated GBD was observed only for the part of investigated GBs.
10.1016-j.matlet.2019.126569	-1		We report two-way shape memory effect (TWSME) induced by Al ion implantation in 6 mu m thick Cu-Al-Ni thin films. The films display an average grain size of 3.7 mu m and a martensitic transformation temperature (M-s) of approximate to 240 K. The film was irradiated with 2 MeV Al ions with a fluence of 6 x 10(15) ion.cm(2) (penetration distance up to ti 1.1 mu m). After irradiation, the film displays well defined TWSME with a radius of curvature of approximate to 1 mm. The results indicate that the irradiation produces mainly changes in the austenitic order.
10.1016-j.matlet.2019.126710	2	corrosion; surface; film; electrochemical; films; spectroscopy; layer; current; solution; potential; resistance; composition; x-ray; ions; showed	Effect of surface roughness on the void formation and intermetallic compounds (IMCs) growth in the Cu-Sn diffusion layers is reported. Different samples having varying surface roughness of the electrodeposited copper were obtained by using different current densities, i.e., 5 mA/cm(2) (type-I) and 50 mA/cm(2) (type-II). Electrodeposited copper samples having higher surface roughness showed the formation of larger voids than the samples having a lower surface roughness, which was attributed to the larger peaks and lower availability of copper at the peaks. The mechanism for void formation and growth was also proposed with the experimental validation. The IMC growth was hampered in samples having higher copper surface roughness due to larger voids at Cu-Cu3Sn interface. The direct influence of under-lying copper surface roughness on the void size, void fraction, and the IMC growth is experimentally demonstrated.
10.1016-j.matlet.2019.126711	-1		In contrast to previous metallization studies that primarily use sputtering to fabricate self-forming Cu-alloy thin films with metallic solutes >= 1 at%, this work examines the feasibility of electroless plating to fabricate Cu films and nanowires that incorporate only 0.1% of MnO. Both surface and grain-boundary segregations of MnO inclusions are observed from secondary ion mass spectrometry (SIMS) and transmission electron microscopy (TEM). The mechanism of self-strengthening of Cu against electrical and thermal stressing involving dual segregation of MnO will be discussed, and the benefit of the extremely dilute metallurgical systems over conventional sputter deposited Cu-alloy systems minimizing residual resistivity components will be presented.
10.1016-j.matlet.2019.127174	-1		Cu-24Pb-2Sn/C10 composite materials were prepared by solid-liquid continuous casting compositing technology. The increasing casting temperature was found to lead to the formation of Cu-24Pb-2Sn (wt%) alloys with second-phase particles in different shapes ranging from coarsely reticulate to continuously reticulate to independently clavate to coarsely clavate shape. Simultaneously, the diffusion layer of element Cu and Fe around the interfaces became thicker with increasing casting temperature. The effect of casting temperature on the microstructure evolution and compositing process were discussed by metallographic and thermodynamic analysis.
10.1016-j.matlet.2020.127432	-1		Metal powders with hierarchical nanostructures are generally designed and fabricated by dealloying with or without assistance of other processes. However, they are mainly nanoporous metal powders and their derivatives which have limited applications, so metal powders with novel nanostructures should be explored further for various applications. Herein, high energy mechanical milling and dealloying were combined for fabricating metal powders with controllable nanostructures. As an example, a nanograins-attached and ultrathin Cu flake powder was fabricated by partial mechanical alloying of a Cu-42 wt%Al powder mixture and subsequent dealloying. The dealloyed Cu powder particles had ultrathin flaky shapes with numerous Cu nanograins being attached to their surfaces, and the microstructure of the as-milled Cu-42 wt%Al powder particles and the dealloyed Cu particles were studied to elucidate the formation mechanism of the unique morphology of the dealloyed Cu powder.
10.1016-j.matlet.2020.127585	0	solidification; phase; magnetic; magnetic field; undercooling; field; liquid; separation; peritectic; immiscible; cu-; dendrite; phase separation; microstructure; primary	In this study, the solidification pathways and the generation of nano-sized Co-rich phase in metastable immiscible Cu-Co alloys with different undercoolings were systematically elucidated. For undercooling above the metastable miscibility gap, solidification commenced in a normal way with the nucleation and growth of primary alpha-Co dendrites. For undercooling below the metastable miscibility gap, primary LLPS and even secondary LLPS took place. Nano-sized Co-rich phase was found to be easy precipitated from the Cu-rich phase after solidification in both cases. The results provide a possibility for the adjustment of immiscible alloys possessing desired properties by nano-sized phases.
10.1016-j.matlet.2020.127780	-1		Present study concerns strengthening of nanocrystalline Cu-matrix by binary and ternary addition of Zr (0.5 at. %) and Nb (1.0 at. %) using ball milling at cryogenic temperature. Zr and Nb having low equilibrium solid solubility in Cu, thus powder blends were subjected non-equilibrium alloying. Mechanically alloyed samples were annealed at different temperatures (600-900 degrees C) for one hour. Stability of the nanocrystalline Cu-matrix even after annealing at 900 degrees C is attributed to the stabilization of nanocrystalline grains by segregation of larger solute atoms (Nb and Zr) along grain boundaries and/or Zener pinning by precipitates like Cu5Zr in Cu-Zr intermetallics.
10.1016-j.matlet.2020.128004	-1		Present study concerns strengthening of nanocrystalline Cu-Nb (1.0 at%) matrix through addition of W using ball milling at cryogenic temperature. Nb and W has low equilibrium solid solubility in Cu, hence powder blend was subjected to non-equilibrium alloying. The studies shows that 1 at% Nb could be dissolved into the Cu solid solution, after mechanical alloying for eight hours of cryo-milling. However, W did not form a solid solution even after eight hours of mechanical alloying. The stabilization of the metastable grains by segregation of large size solute atoms along grain boundaries, was attributed to Orowan strengthening of alloys.
10.1016-j.matlet.2020.128406	-1		A scaling method is described to generate grain boundary affect zone (GBAZ) by scaling the vertex of voronoi edges inside with the same distance. Molecular dynamics simulation (MD) was carried out to analyze the grain size effect on the mechanical behaviors in nanocrystalline Cu-Ag alloy with GBAZ segregation. It is found that the mechanical behavior of Cu-Ag alloy can be effectively improved, especially for segregated domains close to grain boundary (GB). Meanwhile, the flow stress of Cu-Ag alloy indicates the character of size effect.
10.1016-j.matlet.2020.128518	-1		Cu-Zr laminates containing 22 alternative pure Cu and pure Zr metal layers were prepared by 2 cycles accumulative roll bonding method and then subjected to friction stir processing at a rotation speed of 200 rpm and a traveling speed of 100 mm/min using a pinless rotating tool. After processing, a circular arc-like stir zone with a maximum depth of about 0.25 mm was formed on the surface of the laminate. It was revealed that the microstructure was significantly refined into nanoscale at the bottom of the stir zone. While on the top of the stir zone, an amorphous structure was formed due to the severe plastic deformation and the simultaneously thermal promoted crystal to amorphous transformation.
10.1016-j.matlet.2020.129183	-1		This short communication proposes to characterize the influence of Ti-6Al-4V addition on Cu alloy. For this, Cu alloys with additions of 2, 4, and 6 wt% Ti-6Al-4V were manufactured. Morphological, structural and mechanical characterization were performed. Electrical tests demonstrated a decrease of electrical conductivity for the 2 and 4wt% Ti-6Al-4V alloys due the presence of cellular and dendritic precipitates, and it resulted in the increase in hardness of the alloys. However, although the 6wt% Ti-6Al-4V alloy showed a greater hardness, this alloy presented a precipitate-free microstructure, which improved it electrical conductivity.
10.1016-j.matlet.2021.129353	-1		Cu-6Ni-1.5Si alloy having fully fiber-shaped discontinuous precipitates was fabricated by overaging (DP specimen), and subsequently cold-rolled down to 80% reduction in area (CR-DP specimen). The tensile and fatigue strengths of DP and CR-DP specimens were compared to those of CP specimen with nano-sized continuous precipitates by normal aging. The CR-DP specimen showed the highest tensile and fatigue strengths among the specimens tested, and comparable electrical conductivity to the DP specimen. The reason for such an excellent combination of tensile strength, fatigue strength and electrical conductivity was discussed based on the change in microstructure and surface states during stressing.
10.1016-j.matlet.2021.129735	2	corrosion; surface; film; electrochemical; films; spectroscopy; layer; current; solution; potential; resistance; composition; x-ray; ions; showed	The performance of Benzotriazole (BTA) as a stress corrosion cracking (SCC) inhibitor is investigated for Cu-30Zn and Cu-27Ni alloys in Mattsson's solution using electrochemical techniques and slow strain rate test (SSRT). With the addition of BTA, the polarization resistance increases for both alloys. Electrochemical impedance measurements show that BTA can form a protective film on the surface of the Cu-27Ni alloy and shifts the corrosion potential to nobler states. BTA also improves the corrosion resistance of the Cu-30Zn alloy by controlling the cathodic reaction rate and charge transfer resistance. SSRT results reveal that the presence of BTA decreases the susceptibility to SCC for both alloys; this improvement is more significant for Cu-27Ni alloy. Fractographic analysis after SSRT confirms that crack propagation regime is controlled by the BTA concentration. For Cu-27Ni alloy, fracture type changes from intergranular brittle to ductile as the protectiveness of BTA increases. Besides, BTA recovers the ductility by decreasing crack tip dissolution and growth as fewer cracks are observed around the necked area of fractured Cu-30Zn alloy tensile sample.
10.1016-j.matlet.2021.129917	-1		Electrical steel used in high speed motors and motors of electric vehicles and hybrid electric vehicles requires both good magnetic properties and high strength . Existing High-strength electrical steel (HSES) usually sacrifices magnetic properties to increase its strength . In this work, a new state-of-the-art HSES with excellent comprehensive performance is presented in which Cu-rich nanoprecipitates are used to strengthen the alloy. The precipitation behavior of Cu-rich precipitates was investigated by solution treatment and aging processes, and the results showed that the Cu-rich nanoprecipitates dramatically improved the yield strength without deteriorating the magnetic properties. A yield strength of 728 MPa and an iron loss P-1.0T/400Hz of 15.05 W/kg were obtained, and the ratio of the yield strength to iron loss in this work is over twice that of commercial HSES materials.
10.1016-j.matlet.2021.130390	4	transformation; martensite; martensitic; phase; shape; beta; memory; shape memory; temperature; temperatures; martensitic transformation; gamma; transformation temperatures; effect; thermal	In this study, the effects of annealing temperature on thermodynamic parameters and mechanical properties of a CuAlBeNbNiCr alloy were investigated. Thermodynamic parameters were obtained from the results of differential scanning calorimetry (DSC) and the mechanical properties were obtained from the tensile tests. Was observed a reduction, with the increase of temperature, at the magnitude of Gibbs free energy and elastic energies, such as enthalpy and entropy. Regarding the mechanical properties, was verified an increase in the rupture deformation and in the stress induction when the annealing temperature was higher than 800 degrees C. Our results bring to light the effectiveness of the annealing mechanism in altering the thermodynamic and mechanical properties of CuAlBeNbNiCr alloys, indicating the appropriate parameters for heat treatment according to the characteristics required for a practical application of these alloys.
10.1016-j.matlet.2021.130513	2	corrosion; surface; film; electrochemical; films; spectroscopy; layer; current; solution; potential; resistance; composition; x-ray; ions; showed	In this paper, for the first time, the corrosion behavior of 90/10 copper-nickel alloys was investigated systematically by simulating the different sea depths using static weight loss test, XPS depth analysis (argon ion etching), and electrochemical method. The static weight loss test showed that the average corrosion rate increased first, and then decreased with the increase of sea depth . XPS spectra demonstrated that the composition of the corrosion product layer did not change with variation of sea depth . The outer corrosion product was mainly CuO, Cu2O, Cu2Cl, NiO, and gamma-FeOOH, while the inner corrosion product was mainly Cu-2(OH)(3)C1, Cu2O, NiO, Ni(OH)(2), and gamma-FeOOH. Electrochemical impedance spectroscopy exhibited that the inner corrosion layer played an important role in protecting the alloy.
10.1016-j.matlet.2021.130531	6	grain; deformation; strain; strength; dislocation; cu-; tensile; size; ecap; grain size; sfe; ductility; hardening; high; stress	The thermal stability of gradient microstructures in a Cu-0.096%Cr-0.07%Zr (wt%) alloy subjected to equal channel angular pressing (ECAP) at 400 degrees C was studied. The microstructure after intense plastic straining and aging at 300-500 degrees C was almost the same. Aging at 600 degrees C led to the development of a partially recrystallized microstructure. After aging at 700 degrees C, the fully recrystallized microstructure evolved. An increase in ECAP passes from 1 to 12 decreased the recrystallization temperature from 664 degrees C to 617 degrees C. The effect of deformation microstructures and particle precipitation on the recrystallization development is discussed.
10.1016-j.matlet.2021.130894	10	composites; nanoparticles; strength; matrix; high; strengthening; particles; conductivity; composite; electrical; mpa; sintering; ods; grains; mechanical	Refractory high entropy alloys (HEAs) have excellent thermal stability, good strength and toughness, which have great potential application as a second phase in improving microstructure and properties of metal matrix. Here, refractory HEA WTaMoNb is introduced into Cu matrix to synthesize WTaMoNb/Cu nanocomposite by two-step mechanical alloying (MA) and hot pressing sintering (HPS), which owns BCC/FCC structure. During MA, WTaMoNb is firstly prepared and then milled with Cu. Then, WTaMoNb/Cu nanocomposite is synthesised via HPS. The sintered Cu-10wt%WTaMoNb alloy displays an excellent thermal stability, a high tensile strength of 758.3 +/- 20.8 MPa, and an electrical conductivity of 42.5 +/- 1.5% international annealed copper standard (IACS).
10.1016-j.matlet.2021.131069	-1		Cu-base fillers with different V ratios were designed for the butt joining of explosion-welded titanium/steel bimetallic plate. The Cu-V-Ag weld metals are all consisted of Cu solid solution and Fe-Ti intermetallics. The lower V content (similar to 5 wt%) results in the formation of extensive Cu-Ti compounds at Cu5V10Ag/ERTi-1 interface. Brittle sigma-FeV intermetallics are formed at steel/Cu30V10Ag interface when the V content increases to similar to 30 wt%. The regions with considerable amount of FeTi, Cu4Ti, CuTi2 compounds present relatively higher cracking sensitivity. The resultant weld metals shows significantly different hardness distribution and low bending toughness. The strategies for improving the overall mechanical properties in the future are suggested.
10.1016-j.matlet.2021.131124	6	grain; deformation; strain; strength; dislocation; cu-; tensile; size; ecap; grain size; sfe; ductility; hardening; high; stress	In this study, an ultrasonic nanocrystal surface modification (UNSM) was used to enhance mechanical properties of CuSn10Pb10 alloy. Top surface coarse grains were refined into nano-grains (mean size of 45-74 nm) after UNSM. Mechanical testing results revealed that the surface hardness, yield strength and ultimate tensile strength increased after UNSM owing to the formation of nano-grains containing some nano-twins that can be elucidated according to the Hall-Petch relationship. Grain size refinement mechanism was attributed to the increase in dislocation density and the formation of new dislocations, where the accumulation of them at low-angle grain boundaries caused a variation of the grain orientation.
10.1016-j.matlet.2021.131141	-1		High relative density up to 99.7% Cu-0.8Cr alloy samples were fabricated using Cu-0.8Cr alloy powder modified with 0.2 wt% nano-TiC by 320 W 1064 nm Yb-fiber laser powder bed fusion. Nano-TiC modification improved laser absorptivity of the powder from 30.5% up to 59.9%, resulting in sound microstructure and higher prop-erties of fabricated samples. Hardness, tensile strength and elongation of the high relative density samples was up to 98.1 HBW, 225.9 MPa, and 22.1%, respectively.
10.1016-j.matlet.2021.131170	-1		The effects of Y content on the microstructure, mechanical and damping properties of Cu-11Al-3Ni-2.5Mn-chi Y (chi = 0, 0.5, 1, 2, wt%) alloys were investigated. The results of X-ray diffraction (XRD) analysis showed that the alloy was mainly composed of 18R martensite, alpha-Cu and gamma(2)-Cu9Al4. The Y2O3 particles appear after the addition of Y elements. The grain size is reduced to 36.5 mu m when 1 wt% Y element was added, and the combined effect of the grain size reduction and the Y2O3 particles increases the tensile strength to 601.75 MPa. Meanwhile, the alloy at this content has high damping properties, the damping peaks at room temperature and temperature 600 degrees C were 0.038 and 0.24, respectively.
10.1016-j.matlet.2021.131247	-1		Fabrication of gradient-composition alloys is a significant challenge because the adjustment of chemical composition and physical performance is essential. The directed energy deposition manufacturing provided a high-throughput fabrication method for gradient Cu-Fe-Cr alloys, on a master alloy substrate. The liquid diffusion of Fe and Cr contributed to the gradient variation in microstructure and composition. Followed decomposition precipitation improved the hardness of as-fabricated Cu-Fe-Cr alloys, which increased from 84.6 HV to 100 HV. Machine learning was employed to predict the hardness of Cu-18.6Fe-5Cr alloy at different annealing time, the experimental results agreed well with the prediction. These findings indicated that high-throughput manufacturing combined with machine learning can accelerate the design and fabrication of gradientcomposition copper alloys.
10.1016-j.matlet.2021.131512	-1		The effects of ultrasonic impact treatment (UIT) and UIT with equal channel angular pressing (ECAP), on the microstructure of Cu37Zn alloy are studied at ambient and cryogenic temperatures. With decreasing process temperature, highly twinned areas of submicro/nano-scale thickness/spacing, together with dislocation tangles/ cells, are introduced in the alloy. Direct microscopy observation and stored energy release analysis confirm enhanced twinnings in the cryo-UIT and cryo-UIT/ECAP treated alloy that simultaneously provide superior Vickers hardness and formability (twinning-induced plasticity effect).
10.1016-j.matlet.2022.131671	-1		A fabrication route of Cu-10 wt% Al bronze via high-energy mechanical milling and spark plasma sintering (SPS) is proposed. SPS of the ball-milled powder at 700-800 degrees C allows obtaining single-phase Cu(Al) solid solution. Vickers hardness measurements and mechanical tests in compression were conducted on the sintered alloys. The electrical conductivity of the alloys was measured by the eddy current method. The alloy sintered at 800 degrees C shows an attractive set of properties: a hardness of 280 HV1, a proof stress of 760 MPa, a compressive strength of 960 MPa, a deformation at fracture of 5%, and an electrical conductivity of 15% of the International Annealed Copper Standard.
10.1016-j.matlet.2022.131674	6	grain; deformation; strain; strength; dislocation; cu-; tensile; size; ecap; grain size; sfe; ductility; hardening; high; stress	This paper investigated the low cycle fatigue properties of ultrafine-grained Cu with equiaxed or lamellar grains. Although the lamellar grained structure shows higher cyclic softening than the equiaxed one, it exhibits a lowcyclic fatigue life improvement. This contradictory can be explained by the homogeneously distributed cyclic damage in the lamellar grained structure which presents a rotational dynamic recrystallization-led grain refinement and the significant intersecting shear bands during low cyclic fatigue. Simultaneously, plenty of secondary cracks in lamellar grained structure further retard the crack propagation by decreasing the stress concentration at the tip of main crack. The results manifest that the grain morphology is an important microstructural parameter controlling the low cyclic fatigue performance.
10.1016-j.matlet.2022.131790	15	aging; strength; conductivity; electrical conductivity; electrical; mpa; treatment; strengthening; degrees; cu-; cold; precipitation; tensile strength; tensile; iacs	In this work, Cu-Ni-Si alloy was prepared by hot-pressing sintering using Cu, Ni, and Si powders as raw material. The alloy was afterwards exposed to solution treatment at 900 degrees C for 2 h and aging at 450 degrees C for 4 h . The microstructural analysis revealed that the alloy was mainly composed of the granular Ni31Si12 phase at the grain boundaries and the fine delta-Ni31Si phase inside the grains after hot-pressing sintering. After solution treatment, the Ni2Si phase disappeared completely while a small quantity of Ni31Si12 was still observed. However, there was a large amount of fibrous delta-Ni2Si precipitates after aging. The mechanical properties and electrical conductivity of the alloy were tested as well. After aging, the alloy exhibited the best comprehensive characteristics with the hardness of 248.6 HV and the conductivity of 40% IACS. Therefore, the banded structure of Cu-Ni-Si alloys prepared by powder metallurgy and subjected to aging exerts a positive influence on their properties.
10.1016-j.matlet.2022.131937	15	aging; strength; conductivity; electrical conductivity; electrical; mpa; treatment; strengthening; degrees; cu-; cold; precipitation; tensile strength; tensile; iacs	Cu-Cr-Zr alloy can be strengthened by modulating the aging process. In this work, the effect of two-stage aging on the properties of Cu-Cr-Zr solid solution was studied. Hardness, tensile properties and electrical properties were tested, and the microstructures were examined by transmission electron microscope. The results show that pre-aging can facilitate the formation of GP zones in the matrix, and thus accelerate the precipitation of high-density nano-sized phase in a shorter time as compared to that in the one-stage aging process. The two-stage aging route harmonizes the strength, ductility and electrical conductivity of the alloy, and provides an accessible strategy to ameliorate the comprehensive properties of the Cu-Cr-Zr alloy.
10.1016-j.matlet.2022.132737	-1		Metal-based micro/nanomaterials on insulators have attracted extensive attention in various applications, such as transparent conductive electrodes, smart textiles, and sensors. Herein we proposed a straightforward method for fabricating metal-based micro/nanomaterials on insulators by shielding ion transportation during electrochemical migration. Voltage-stressing experiments were conducted on two parallel Cu electrodes separated by water, with an insulator inserted on the cathode inner surface. Since the insulator shielded the transported metal ions and prevented the electrical short, Cu-based dendrites composed of nanowires and nanoparticles were successfully fabricated on the insulator. The procedure can be applied to design diverse metal-based micro/ nanomaterials on arbitrary insulators for versatile applications.
10.1016-j.matlet.2022.133097	-1		In this investigation, a novel heredity phenomenon was reported that the mechanical properties of thermo-mechanically processed Cu-15Ni-8Sn alloys were improved by refining the as-cast structure. This underlying mechanism of hereditary strengthening was carefully analyzed, which is mainly contributed to the additional dislocation proliferation induced by structure refinement and accelerated precipitation effect on strengthening phases. The strengthening mode changed from grain refinement strengthening in as-cast state to dislocation strengthening and precipitation strengthening for aged alloys.
10.1016-j.matlet.2022.133362	-1		In this research, phase transformations and porosity formation were analyzed for a heat-treated Cu-20Sn alloy. Reached porosity levels led to introduce a new method for manufacturing Cu-Sn foams with micropores, which could be part of a whole manufacturing process to obtain hierarchical foams. Microporosity generation was possible by modifying the conventional heat-treatment to the Cu-20Sn alloy, overheating it at 400, 550, 750 and 800 degrees C for 1, 3 and 5 h, followed by quenching in water. In all cases, phase transformations took place, which was analyzed using X-ray Diffractometry (XRD), Optical Microscopy (OM), and Scanning Electron Microscopy (SEM). Results also showed the formation of connected and not-connected pores, although extensive porosity was only generated under certain conditions. The highest porosity was 21 %, obtained for a heat-treatment of 750 degrees C during 1 h due to the transformation of beta phase, reaching maxima pore sizes of-200 mu m.
10.1016-j.matlet.2022.133373	-1		In this work, a simple-yet-powerful processing method was applied successfully to a Bi-containing brass alloy (Cu-30wt%Zn-3wt%Bi), which utilized multi-pass proper annealing following medium-strain cold-rolling deformation. Both strength and ductility of the alloy have been improved simultaneously. This is mainly due to the redistribution of the bulky Bi phase along the rolling plane as well as the grain refinement of the brass matrix. Bi phase pancaking reduces the possibility of cracking at the early stages during straining whilst grain size refines continuously cycle-by-cycle, and the matrix is strengthened. The processing method could be applied to other alloys with similar microstructure.
10.1016-j.matlet.2022.133392	-1		To provide a better way for the property enhancement of Cu-based shape memory alloys (SMAs), combined use of inoculation and hot rolling was adopted to modify the microstructures of a Cu-Al-Ni-Mn-Ti SMA. Through in-depth microscopic observation, it is confirmed that LaB6 particles in the Al-La-B inoculant can be used as effective heterogeneous nucleation centers of the Cu-Al-Ni-Mn-Ti melt due to their good lattice matching rela-tionship with the Cu-Al-Ni-Mn-Ti SMA, so they can significantly refine the grains and martensites. Hot rolling does not degrade the refining effect and can further significantly improve the damping of the Cu-Al-Ni-Mn-Ti SMA. Correlated mechanisms were discussed.
10.1016-j.matlet.2022.133395	6	grain; deformation; strain; strength; dislocation; cu-; tensile; size; ecap; grain size; sfe; ductility; hardening; high; stress	Via equidistance scaling method, several parts of the segregated domains from granular interior to grain boundary are identified. Based on this method, the model of nano-crystalline (NC) Cu-Ag alloy with gradient segregation is constructed. The issue how the solute concentration (SC) distribution is more conducive to the strength enhancement is explored by molecular dynamic (MD) simulation. The simulation results reveal that sample with higher intra-granular SC possess more dislocation activities, thinner amorphous inter-granular films (AIFs), more homogeneous deformation and higher flow stress at plastic stage. The results turn the opposite way in sample with higher SC nearby grain boundary. Meanwhile, the observed phase transition is analyzed during the deformation progress.
10.1016-j.matlet.2023.133983	15	aging; strength; conductivity; electrical conductivity; electrical; mpa; treatment; strengthening; degrees; cu-; cold; precipitation; tensile strength; tensile; iacs	FCC phase High-entropy alloys (HEAs) has excellent plasticity and toughness but low tensile property. To strengthen the HEA without plasticity reducing, Cu28.36 Ni22.32 Fe19.12Co15.17Cr12.26Mo2.77 HEA with dual FCC phase were successfully prepared by plasma arc additive manufacturing using a combined cable wire with multielement composition. The results show that the prepared alloys were composed of Cu-poor FCC1 and Cu-rich FCC2, along with a small amount of Mo-rich precipitation phases. The ultimate tensile strength, yield strength is 531 MPa, 332 MPa, it is increased by 14.48 % and 32.75 % compared with arc melting technology with excellent elongation of 32.26 %. Compared with the vacuum induction melting technology, the strength is increased by 276.5 %. Dual phase obviously increased the mechanical properties. The Co and Cr element in the alloy is relatively low, which can reduce the production cost.
10.1016-j.matlet.2023.134092	-1		The fabrication of Cu alloys component by wire arc additive manufacturing is a challenging exploration due to their high thermal conductivity. In this study, CuCrZr alloy was deposited successfully, the microstructure and properties of different zones have been investigated. The results showed that the grain morphology in terms of shape, size, and orientation varied along the build direction. Columnar crystals of different sizes were the major grain morphology. Along the building direction, the hardness tended to decrease with large fluctuations. Specimens in travel direction had slightly higher mechanical strength but lower elongation in comparison with those in build direction. The electrical and thermal conductivities of specimens with no visible defects were significantly higher than those of specimens in other additive manufacturing methods using metal powder as raw material.
10.1016-j.matlet.2023.134556	-1		Based on the concept of microstructure control and multiphase doping, a novel strong-textured porous (STP) Cu-Al-Mn (CAM) shape memory alloy was fabricated through multi-stage sintering process. Porosity ranging from 31.1 to 11.4 % and the largest near-elastic deformation approached 8.0% were achieved in the STP Cu71Al18Mn11 alloy. Through in-depth characterization, it is confirmed that STP-CAM has less gamma 2 phase compared to porous ordinary polycrystalline alloy, and exhibits strong (001) and (101)-oriented texture along the direction of sintering pressure, as well as low angle grain boundaries, which contributes to the large near-elastic deformation observed in this novel porous SMAs.
10.1016-j.matlet.2023.134771	-1		The deformation behavior of nanoscale precipitates and their interaction with the matrix in the alloys have been rarely explored. In this study, the deformation mechanism of nanoscale soft Cu precipitates and its interaction with ferritic matrix during rolling deformation were studied at the atomic scale. The ellipsoidal Cu precipitates with an average diameter of about 34 nm are flattened into slender rods under rolling reduction of about 70% and are elongated along the rolling direction. The initial K-S orientation relationship was transformed into N-W orientation relationship after rolling deformation. The shear deformations are induced in Cu precipitate near the interface and the serrated boundary are formed combined with the plastic flow of the matrix. A successive lattice torsion band with a width of 1.5 similar to 10 nm was formed at the serrated interface, while there is only local lattice distortion at the smooth interface. The Cu precipitates maintained good deformability and excellent strain coordination ability under severe deformations. These results have important value for understanding the deformation mechanism of Cu precipitates.
10.1016-j.matlet.2023.134773	14	strength; properties; conductivity; electrical; mechanical; cu-; grain; mpa; electrical conductivity; aging; precipitation; phase; mechanical properties; tensile; phases	The metallic deposits produced by cold spray additive manufacturing (CSAM) often fail to meet the structural requirements, necessitating post-treatment. This study introduces induction heat (IH) to heat-treat the Cu deposit for the first time, and its influence on deposit microstructure and mechanical properties was analyzed. Microstructure analysis shows that IH treatment reduces dislocations and prevents pore formation, but increases grain size. Electrical conductivity significantly increases from 15 MS/m in the CSAM deposit to 31 MS/m after IH treatment, indicating improved bonding between particles. IH treatment can vastly enhance the mechanical properties of the CSAM deposit, increasing its tensile strength from 58 MPa and elongation at break from 1.5% to 118 MPa and 7.5%, respectively. Overall, IH treatment had a positive impact on interparticle bonding and mechanical properties.
10.1016-j.matlet.2023.135116	0	solidification; phase; magnetic; magnetic field; undercooling; field; liquid; separation; peritectic; immiscible; cu-; dendrite; phase separation; microstructure; primary	The interaction between the massive 6-Fe nuclei during rapid solidification is studied through atomization and molecular dynamics simulation of Cu-Fe monotectic alloys, based on its liquid separation behavior. The experimental results showed that E1/3/9 grain boundaries (GBs) with lower interfacial energy are preferentially expressed. MD results further proved that 6-Fe nuclei in liquid Cu can rotate to E1/3 relationship, following the boundary energy reduction path . Therefore, the mechanism of special grain boundary formation through grain rotation in rapid solidification processes is demonstrated.
10.1016-j.matlet.2023.135405	-1		Morphological and structural changes of spark plasma sintered Cu-10 wt% Al materials in salt spray environment were studied. The tested materials possessed the same elemental composition but different phase compositions (Cu-Al composite, Cu(Al) solid solution and Cu-Cu(Al)-Cu9Al4 alloy). The oxide films formed on the surface of the corroded samples were confirmed to be enriched with Al. The subsurface regions of the Cu-Al composite and Cu (Al) solid solution did not reveal any microstructural changes after the salt spray test. When the Cu-Cu(Al)Cu9Al4 alloy corroded, the aluminum contained in the alloy oxidized such that the oxide particles formed both on the surface of the sample and in the subsurface region. While the Cu-Al composite and Cu(Al) solid solution maintained integrity, the Cu-Cu(Al)-Cu9Al4 alloy experienced swelling and cracking during the salt spray test.
10.1016-j.matlet.2023.135805	-1		In this work, the influences of sintering temperature, duration, and pressure on the properties of Cu-0.6Cr-0.1Zr alloy were investigated by the spark plasma sintering through L9(33) orthogonal experiment design. The optimum parameters were determined at 850 degrees C with 50 MPa for 20 min. Subsequently, a high-throughput sample of Cu-xCr-0.1Zr (x = 0-0.9 wt%) was prepared under the aforementioned experimental conditions to explore the impact of Cr content on the microstructure and properties of Cu alloys. It was found that Cr addition enhanced mechanical properties while reducing the electrical conductivity in the alloy. By striking a balance between mechanical properties and electrical conductivity, an optimum Cr addition level of 0.6 wt% was identified for Cu-xCr-0.1Zr alloy.
10.1016-j.matlet.2023.135815	14	strength; properties; conductivity; electrical; mechanical; cu-; grain; mpa; electrical conductivity; aging; precipitation; phase; mechanical properties; tensile; phases	Incorporating Cr into Cu-Ag alloys offers potential for enhancing mechanical properties, yet the intricate in-fluence of microstructural characteristics at varying Cr concentrations on performance remains unclear. In this study, Cu-3 %Ag-(0.1-4 %Cr) alloys were investigated, optimizing performance through sequential solution processing and aging. After aging at 450 degrees C/2h, Cu-3 %Ag binary alloys featured solely discontinuous Ag pre-cipitates, while Cr-containing alloys exhibited prominent continuous Ag precipitation. Modest Cr content significantly increased alloy hardness, with a 37.4 % improvement in the 0.5 % Cr alloy. Concurrently, Cr introduction caused a modest decline in electrical conductivity. These findings illuminate the strengthening mechanisms in Cu-Ag-Cr alloys, emphasizing the substantial presence of continuous Ag precipitates and fine Cr precipitates during aging, collectively enhancing the alloy's microstructure.
10.1016-j.matlet.2024.136164	-1		Interface structure plays a crucial role in enhancing the electrical conductivity and mechanical properties of copper/graphene composites, thereby influencing their potential applications. In this study, we introduced carbide-forming elements (Cr, Nb, W) and expected to generate nano carbide particles at the interface to improve the interface bonding by in-situ preparation. Among these, the CuCr/graphene composite exhibits the best performance with electrical conductivity of 97 % IACS and hardness of 82 HV. The cold-drawn wire possesses a high tensile strength of 518 MPa. At the Cu/graphene interface, an optimal quantity of nanometer chromium carbide (Cr3C2) particles in situ formed, enhancing the interface bonding and resulting in the composite achieving both high conductivity and high strength .
10.1016-j.matlet.2024.136178	-1		This work investigates Cu-In alloy at 15% indium for wetting behaviour after heat treatment at 800 0C. The system is observed to show wetting behaviour at triple junction (grain junction) through Scanning electron microscope imaging. It is observed in energy dispersive spectroscopy that after annealing, increased segregation of indium near triple junction is responsible for this wetting behaviour. The current work is critical to development of advanced materials with better mechanical characteristics at high temperatures.
10.1016-j.matlet.2024.136412	-1		Cu-Cr pseudobinary alloys have excellent electrical properties and are widely used in many industries. Laser additive manufacturing can effectively avoid the shortcomings of traditional methods for preparing Cu-Cr alloys. However, the high reflection of Cu powder to laser energy brings difficulties to industrial practice. The assembled Cu powder is used as raw material to absorb more laser energy through the outer layer of Cr powder, thereby improving the melting efficiency of the powder and the quality of the molten pool. Laser remelting of unmelted Cr powder can inhibit the uneven nucleation and growth of precipitated Cr, and improve the uniformity of electrical conductivity and element distribution. This study provides a new idea for the preparation of highperformance Cu alloys.
10.1016-j.matlet.2024.136693	14	strength; properties; conductivity; electrical; mechanical; cu-; grain; mpa; electrical conductivity; aging; precipitation; phase; mechanical properties; tensile; phases	This study examines the evolution of mechanical properties and texture of hot rolled Cu -Be alloy sheets with varying Be content. The Cu-3.0Be alloy exhibits superior performance attributed to its fine grain structure, weaker texture, and lower dislocation density.
10.1016-j.matlet.2024.137068	-1		In this study, three kinds of Cu-Nd alloys were prepared. The effect of Nd content on the dynamic impact behavior of the Cu-Nd alloys and its strengthening mechanism were studied. The results show that during the dynamic impact process, nano-scale oxide particles are precipitated in the alloy matrix, and a large number of cracks are formed along the grain boundaries, and the formation of shear bands and thermal grooves are also observed in local areas. With the increase of Nd content, the compressive strength of the alloys increases significantly, the grain size is refined, the number of twins increases, the grooves are much deeper and the number of the precipitated nano-oxide particles also increase significantly. In addition, due to the refinement of the grain size, the crack length is reduced. The increase of the alloy strength is mainly attributed to the nanoscale oxide precipitation strengthening and grain refinement strengthening.
10.1016-j.matlet.2024.137445	-1		Cu-13Al-4Mn (wt%) shape memory alloys were fabricated by additive manufacturing and exhibits good shape memory effect. Corresponding microstructural evolution was revealed under the compressive condition. Results indicate that stress-induced twin-related transformation played an important role in deformation process. At the initial deformation stage, the reorientation of (-1-1) twin was activated. With the pre strain increased, detwinning and crossed deformation twin occurred, which accompanied by massive stacking faults, Lomer-Cottrell (L-C) locks, resulted in the formation of irrecoverable strain.
10.1016-j.matlet.2024.137465	-1		This study explores the effects of high-pressure torsion (HPT) processing on the microstructural and mechanical properties of Cu-30Zn alloy. Thin disc specimens of annealed Cu-30Zn were subjected to HPT at room temperature under a pressure of 6 GPa with 10 rotational turns. Microstructural analysis using scanning electron microscopy (SEM) and transmission electron microscopy (TEM) revealed a significant refinement to an ultrafine-grained structure with grain sizes mainly below 100 nm, increased dislocation density, and the formation of mechanical nanotwins. This microstructural transformation resulted in a remarkable increase in Vickers microhardness by approximately 250 %, from 79 +/- 4 HV in the annealed state to 275 +/- 7 HV after HPT processing. Additionally, scratch resistance tests demonstrated improved performance in the HPT-processed alloy, with reduced wear volume loss, lower coefficient of friction, and more uniform scratch track morphology compared to the annealed material. These results indicate that HPT processing enhances the hardness and wear resistance of Cu-30Zn alloys, suggesting its potential for applications requiring high durability and strength, given the limited hardening mechanism and wear resistance of conventional single-phase brass.
10.1016-j.matlet.2024.137515	14	strength; properties; conductivity; electrical; mechanical; cu-; grain; mpa; electrical conductivity; aging; precipitation; phase; mechanical properties; tensile; phases	The increase in beryllium content in Cu-Be alloys results in an unexpected reduction of hot-compressed flow stress at 780 degrees C and a strain rate of 1 s-1, accompanied by grain coarsening. This phenomenon can be primarily attributed to the rising volume fraction of the hard and brittle /3 phase with increasing beryllium content, which enhances dynamic recrystallization and consequently contributes more significantly to softening deformation.
10.1016-j.matlet.2024.137601	16	wear; composite; composites; powders; milling; particles; powder; wt; sliding; friction; hardness; matrix; mechanical; surface; properties	The role of interfaces in metal matrix composites of Cu-Ag alloys deformed in tension is studied. Five types of samples are considered: alloys prepared by traditional casting and alloys compacted by spark plasma sintering are completed with pure elements, copper and silver. Due to more pronounced interfaces in the cast alloys, plastic deformation occurs at higher stresses and hence the dendritic structures of cast alloys are less suitable for applications.
10.1016-j.matlet.2024.137865	-1		In this study, we report tensile properties of a high-strength ultrafine-grained Cu-5vol.%Al2O3 nanocomposite at temperatures ranging from room temperature to 700 degrees C. We found that the nanocomposite exhibits a strong temperature-dependent plastic flow, and explained the observed different plastic deformation behaviors with the dislocation forest cutting, dynamic recrystallization, and grain boundary diffusion mechanisms, respectively.
10.1016-j.matlet.2025.138679	14	strength; properties; conductivity; electrical; mechanical; cu-; grain; mpa; electrical conductivity; aging; precipitation; phase; mechanical properties; tensile; phases	This study investigates the microstructure, mechanical properties, and shape memory behavior of a series of (84x) Cu-12Al-4Ni-xAg (x = 0, 4, 8, 12 wt%) alloys with varying Ag contents. The alloys predominantly exhibited martensitic phases: 18R and 2H, with the 18R phase becoming more prevalent as Ag was introduced. The formation of the Ag2Al phase and microstructural refinement contributed to significant improvements in mechanical properties. Notably, the alloy with 8 wt% Ag (x = 8) exhibited peak compressive strength of 947.1 MPa, the compressive strain of 14.1 %. Additionally, the inclusion of Ag enhanced the shape memory effect of the alloys, with the x = 8 alloy demonstrating a reversible strain of 4.7 % upon heating after an 8 % pre-strain.
10.1016-j.matlet.2025.138835	16	wear; composite; composites; powders; milling; particles; powder; wt; sliding; friction; hardness; matrix; mechanical; surface; properties	In this work, a pulsed-periodic laser was used for single-tracks formation on Cu-40Cr-10TiC (wt%) composite obtained by mechanical alloying to study the effect of laser melting on its microstructure and microhardness. The mixture of starting components was ball milled for up to 10 h followed by hot pressing. It was shown that after mechanical alloying, composite particles with dispersed homogeneous microstructure and microhardness of 548 HV were formed. After laser melting, the microhardness decreases to 294 HV. Chromium crystallizes as large layered regions and spheroids with 0.5-8 mu m in size. Chromium carbide formation was also observed. The best structure was obtained at 260 W peak power.
10.1016-j.matlet.2025.139187	-1		Electroconductive copper alloys with ultra-high strength are essential materials for developing electrical connectors. In this work, high-throughput experiments of diffusion multiple and nanoindentation were conducted on a Cu-Co/Cu-Ni/Cu-Si diffusion multiple, resulting in a Cu-7.2Ni-1.5Si-0.2Co alloy was predicted and fabricated with a strength and conductivity of 1050 +/- 10 MPa and 29.1 +/- 0.1 % IACS. The heterostructure with heterogeneous grains and multi-scale (Ni, Co)2Si particles were detected in the studied alloy, which refined grains and improve its mechanical properties. Compared with traditional experimental methods, this high-throughput method enables a quick composition optimization and generates a database of series copper alloys through diffusion multiple and nanoindentation.
10.1016-j.matlet.2025.139282	14	strength; properties; conductivity; electrical; mechanical; cu-; grain; mpa; electrical conductivity; aging; precipitation; phase; mechanical properties; tensile; phases	Cu-Zn alloys are widely used in electrical and automotive applications due to their excellent conductivity and plasticity. This study developed self-lubricating composites with gradient Y2O3 concentrations (0-2 wt%) using acoustic resonance mixing to enhance strength and wear resistance. Results indicate that incorporating 2 wt% Y2O3 formed a continuous reinforcing matrix, increasing hardness to 1.5 GPa-a 9 % enhancement over undoped specimens. The wear rate decreased by 35 % to 1 x 10-6 mm3/(N & sdot;m), with the friction coefficient remaining stable at 0.11-0.13. Finite element analysis revealed that 280 nm Y2O3 particles strengthened the material by impeding dislocation motion, while nano-scratch tests demonstrated the alloy's homogeneous microstructure and stable linear response.
10.1016-j.mattod.2022.03.002	-1		High purity metals are increasingly demanded in modern manufacturing industries, but their processing and applications are limited by a dilemma that purer metals are thermally and mechanically less stable. The reduced stability of pure metals originates from the weakened drag effect of impurity atoms on the mobility of grain boundaries (GBs) that are hard to stabilize without alloying. Following recent studies on stabilizing nanograined metals by tailoring structures of GBs, here we report that structural relaxation of GBs breaks the purity-stability dilemma in pure Cu. Contrary to the conventional impurity effect, thermal stability and hardness of nanograined Cu samples with relaxed GBs increase (rather than decrease) with higher purities. The discovered anomalous impurity effect, owing to suppression of GB relaxation process with impurity atoms, offers an alternative vector to stabilizing purer metals for advanced processing and applications.
10.1016-j.measurement.2010.02.013	4	transformation; martensite; martensitic; phase; shape; beta; memory; shape memory; temperature; temperatures; martensitic transformation; gamma; transformation temperatures; effect; thermal	In this study, the hysteresis errors of 17-4 PH precipitation hardened stainless steel, aged Cu-Be (copper beryllium) alloy and AISI 4340 steel, which are commonly used as spring materials for sensors, were determined. Various heat treatment processes were applied to the samples of sensor materials in order to decrease the hysteresis error. The effect of the microstructure on the hysteresis error was also investigated. According to the results, the hysteresis errors were increased 2-3 times for higher annealing temperatures or holding time after solutionized. The results showed that the hysteresis characteristics can be improved by the application of suitable thermo-mechanical treatment processes. Microstructural changes can effect the sensor behavior and increase or decrease measurement errors. The lowest hysteresis errors were obtained in short-term aged for Cu-Be material and fine martensite for AISI 4340 steel and short-term aged for 17-4 PH steel. Crown Copyright
10.1016-j.mechmat.2005.05.023	4	transformation; martensite; martensitic; phase; shape; beta; memory; shape memory; temperature; temperatures; martensitic transformation; gamma; transformation temperatures; effect; thermal	Motivated by eventual applications as high temperature actuators, cyclic isothermal stress-induced transformations of Cu-13.3Al-4.0Ni (wt%) single crystal wires with stress-free transformation temperatures: M-r = 80 degrees C, M-s = 100.5 degrees C, A(s) = 104.5 degrees C and A(f) = 117 degrees C were studied under the two adverse conditions of high overall strain (9%) and an overheating temperature (175 degrees C for 30 min). Wires were subjected to isothermal stress cycling at 25 degrees C using an Instron testing machine with environmental chamber until fairly repetitive stress-strain response was obtained. These tests were repeated on the same specimen at progressively higher temperatures of 40, 60, 80 and 100 degrees C. It is seen that the initial cyclic response is primarily shape memory whereas the subsequent cyclic response is primarily pseudoelastic, attended by some residual inelastic deformation. Tests on a different virgin specimen at 100, 120, 140 and 160 degrees C showed a similar trend. This points to the possibility of a downward shift in the stress-free transformation temperatures. Possible reasons are generation of dislocations as well as the domination of alpha-martensites over beta-martensites due to the overheating temperature and stress cycling. The effect of stress cycles on overall strain on full loading, after unloading and after heating in between stress cycles has been discussed.
10.1016-j.mechmat.2011.09.007	4	transformation; martensite; martensitic; phase; shape; beta; memory; shape memory; temperature; temperatures; martensitic transformation; gamma; transformation temperatures; effect; thermal	The objective of the study is to analyze the martensitic microstructure evolution in a shape-memory alloy during a stress-induced transformation. Two full-field measurement techniques are used for this purpose: the grid method to obtain strain maps and infrared thermography to measure temperature variation maps at the same time. The specimen is a monocrystalline Cu-Al-Be alloy which is austenitic at ambient temperature. Austenite progressively transforms into martensite during the mechanical loading and the impact of this transformation in terms of strain and temperature is analyzed in this paper. The spatial resolution of the strain maps obtained enables us to distinguish some typical martensitic microstructures such as martensite needles, habit planes and X-shaped microstructures, so the evolution of these microstructures during the test is presented and discussed with strain maps obtained at some points regularly spaced on the stress-strain curve. Infrared thermography provides some additional information to analyze the transformation phenomena. Maps of latent heat are calculated from temperature maps thanks to a specific post-processing procedure. Interestingly, the microstructure evolution during the loading phase is found to be different of the evolution during the unloading phase although the specimen precisely returns to zero strains at the end of the cycle. In the last part of the paper, the values of the measured in-plane strain components are used to identify the martensite variants that likely appear in the specimen during the loading phase of the test. This identification is based on some crystallographic compatibility calculations.
10.1016-j.mechmat.2013.07.008	6	grain; deformation; strain; strength; dislocation; cu-; tensile; size; ecap; grain size; sfe; ductility; hardening; high; stress	Constant amplitude fatigue crack growth tests were carried out on commercial and high purity nanostructured copper processed by High Pressure Torsion (HPT). Due to strong grain refinement the HPT processed materials show higher tensile strength but also faster crack growth rates when compared to coarse grained material. Crack growth curves of nanostructured copper determined at different stress levels, however, showed that the occurrence of grain coarsening at low stress amplitudes leads to a retardation of crack growth in commercial and high purity HPT Cu. This effect was not observed for high purity HPT Cu with a bimodal microstructure. Crack propagation rates depend significantly on the coarsening phenomenon which on the other hand depends on the applied stress amplitude. A comparison of these results with cyclic deformation tests in the high cycle fatigue regime suggests that. grain coarsening during crack growth depends more on the stored energy of the materials while a similar coarsening during cyclic deformation depends more on the activation enthalpy for annealing of defects.
10.1016-j.mechmat.2013.09.013	-1		In many practical applications, creep damage is the limiting factor of a component's lifetime. A micromechanical model of creep induced grain boundary damage is proposed, which allows for the simulation of creep damage in a polycrystal within the framework of finite element analysis. The model considers grain boundary cavitation and sliding according to a micromechanically motivated cohesive zone model while creep deformation of the grains is described following the slip system theory. The model can be applied to idealised polycrystalline structures, such as a Voronoi tessellation or, like demonstrated here, to real grain structures of miniature creep specimens. Creep tests with pure Cu single crystals and with a coarse-grained polycrystalline Cu-1 wt% Sb alloy at 823 K have been performed and used to calibrate the polycrystal model. The grain structure of the polycrystalline Cu-Sb specimens has been revealed by the EBSD method. Extensive grain boundary sliding and cavitation has been observed in the crept specimens. Grain boundary sliding has been found to promote wedge-type damage at grain boundary triple junctions and to contribute significantly to the total creep strain. Furthermore, the assumed stress sensitivity of the models grain boundary cavity nucleation rate strongly influences the development of wedge-type damage.
10.1016-j.mechmat.2015.05.008	-1		Severe plastic deformation (strains > 100%) has been shown to create significant grain refinement in polycrystalline materials, leading to a nanometric equiaxed crystalline structure for such metals as aluminum, copper and nickel alloys. This process, termed continuous dynamic recrystallization, is governed by evolution of the dislocation structure, which creates new grain boundaries from dislocation walls. In the proposed model, plasticity occurs which firstly involves dislocation multiplication, leading to strain hardening limited by dynamic recovery. After a critical dislocation density is reached new grain boundaries are formed by condensation of walls of dislocations, creating a new stable configuration that is favored due to a reduction of the system free energy. This evolution of the microstructure continues to develop, with a consequent progressive decrease in the average grain diameter. The proposed model provides a quantitative prediction of the evolution of the average grain size, as well as the dislocation density, during continued plastic strain. The model can be calibrated by use of results from any experiment that involves large plastic deformation of metals, subject to negligible annealing effects. In this paper, the model has been calibrated, and consequently validated, through experiments on machining of Al 6061-T6.
10.1016-j.mechmat.2017.08.004	6	grain; deformation; strain; strength; dislocation; cu-; tensile; size; ecap; grain size; sfe; ductility; hardening; high; stress	Three kinds of nanostructure (NS) Cu-Al alloys (Cu-2.57%Al, Cu-6.87%AI and Cu-11.14%Al) were produced via equal channel angular pressing at room temperature and the smallest grain size achieved was 93 nm. Mechanical properties of NS Cu-Al alloys were studied by compression tests over a wide range of strain rates (5 x 10(-4)-4 x10(3) s(-1)). The microstructure of NS Cu-Al alloys before-and-after mechanical testing were examined by transmission electron microscope (TEM). Deformation mechanisms of NS Cu-Al alloys with different Stacking Fault Energy (SFE) were also discussed. It is worth mentioning that the post loading observations of NS Cu-11.14%Al (with the lowest SFE loaded at a high strain rate of 4 x 10(3) s(-1)) by Optical and Scanning Electron Microscope verified the appearance of Adiabatic Shear Band (ASB) which is found rarely in nanostructured FCC metals. TEM observation showed that the nanoscale grains in ASBs were much smaller and cleaner in contrast to the grains with high density of defects outside the bands. It should be a consequence of the recrystallization because of adiabatic temperature rise inside the band. The reasons for the formation of ASBs in NS FCC alloys were also explored and explained.
10.1016-j.mechmat.2018.11.001	-1		In this study, an investigation of the low-cycle fatigue properties of diffusion alloyed Cu-Ni-Mo sintered steel (as-sintered specimens) with consideration of additional heat treatment effects (as-hardened specimens) is presented. The microstructure of this powder metallurgy steel was found not uniform for both as-sintered and as hardened specimens. The experimental testing was performed in a low-cycle fatigue regime on the servo-hydraulic testing machine under load control with stress ratio R = 0.1. The experimental results have shown that additional hardening increases the fatigue strength of the material significantly. Furthermore, the fatigue cracks propagated mainly through the regions with the highest porosity. The as-sintered specimens exhibited a combination of brittle and ductile fracture, while the as-hardened specimens exhibited predominantly ductile fracture. By determining low-cycle fatigue parameters, it is possible to further enhance the estimation of the number of loading cycles required for the fatigue crack initiation of different sintered machine parts and structural elements, while considering the effect of additional hardening due to the heat treatment processes.
10.1016-j.mechmat.2024.105074	6	grain; deformation; strain; strength; dislocation; cu-; tensile; size; ecap; grain size; sfe; ductility; hardening; high; stress	The stacking fault energy (SFE) effect on nanocrystalline metal deformation mechanisms has been extensively studied from dislocation and grain boundary perspectives. Compared to homogeneous nanocrystalline structures, the gradient nanograined (GNG) structure exhibits varied grain sizes, resulting in different SFE effects across regions during the hetero-deformation process. In this work, molecular dynamics (MD) simulation is conducted on GNG Cu-Ni binary alloys with incremental Ni concentration, to investigate the SFE effect at different deformation stages of the GNG structure. It is revealed that the elastic deformation stage shows a close relationship with alloy intrinsic property (e.g. elastic modulus) from Ni concentration variation, with neglectable SFE effect. Under the hetero-deformation stage, different from the homogeneous polycrystalline counterpart, the effect under high SFE condition is demonstrated from the overall dislocation density decline and the competition between the perfect and partial dislocations in the gradually varied grains across the GNG structure, which finally results in lower strain gradient, geometry necessary dislocation density, and a less effective heterodeformation process. The active GB sliding and migration are found to offset this dislocation density decline in the sample with the relatively high SFE, which brings in higher GB stress concentration and larger GB free volume of the GNG structure. Besides, the GB relaxation across the GNG structure under the high strain rate tensile loading is also illustrated and discussed. The results further support the essential deformation mechanism underlying heterostructure materials.
10.1016-j.mechrescom.2016.06.003	-1		The involvement of the dynamic embrittlement phenomenon during tensile tests of a Cu-Ni-Si alloy leads to decohesion of grain boundaries, which is dependent on the energy decrease at grain boundaries caused by sulfur segregation. The severity of dynamic embrittlement increases with the increasing of temperature and/or the decreasing of straining rate. A crystal plasticity approach associated with the cohesive zone method is used in order to analyze the fracture caused by dynamic embrittlement. A cohesive zone model is used to describe the grain boundary cracking and one of its main parameters is identified using a homogenization scheme for the nonlinear response of a polycrystal in presence of degradable grain boundaries. Numerical simulations are carried out in order to simulate the mechanical behavior related to dynamic embrittlement under different conditions of strain rate and temperature. The obtained results such as tensile stress-strain curves and intergranular crack distribution are compared with experimental observations.
10.1016-j.mee.2009.07.010	-1		Electromigration effects in interconnect metallizations cause a need for materials with superior resistance against electromigration failure but with adequate electrical properties. In principle, Cu(Ag) alloys are potential candidates to become an interconnect material of the next generation of microelectronic devices. Therefore, in the following paper the electroplating of such Cu(Ag) alloys from a sulfuric acid electrolyte solution with varying silver content in a home built deposition tool is presented. Besides the general deposition characteristics, the growth mode of the films and the deposition into trenches will be discussed. The investigations show that Cu(Ag) alloys can be deposited with adequate homogeneity of the film thickness by electroplating. Furthermore, the electrical resistivity is low enough to assure a use of these films for interconnect applications. However, distinct island growth and insufficient trench filling capabilities lead to the fact that the additive composition needs to be optimized for Cu(Ag) thin film electroplating.
10.1016-j.microc.2015.12.017	2	corrosion; surface; film; electrochemical; films; spectroscopy; layer; current; solution; potential; resistance; composition; x-ray; ions; showed	Archaeological silver-copper alloys are usually affected by silver enrichment of the near surface layers, either intentional or fortuitous. In previous studies we have shown that surface composition of archaeological bronzes and leaded copper coins obtained by XRF can be corrected by means of gamma-ray transmission (GRT) to obtain the bulk composition. In the present work, we have studied the applicability of this method to silver-copper alloys and established the most suitable conditions for the GRT correction calculation. The analysis of the microstructure of the core and the corrosion layers of a set of silver roman coins shows that copper could be leached from the surface during corrosion and cleaning treatments, resulting in an apparent silver surface enrichment. After the correction calculations by GRT method, the concentrations of the major elements, Ag and Cu, were found to be in good agreement with the bulk composition obtained by direct analysis of the cut cross-sections of the coins. The GRT method shows to be a useful tool to study metal artefacts having a surface composition modified by corrosion or cleaning treatments.
10.1016-j.microc.2018.08.033	2	corrosion; surface; film; electrochemical; films; spectroscopy; layer; current; solution; potential; resistance; composition; x-ray; ions; showed	Seven coins, covered with black concretion coating, found in the Byzantine-period Ma'agan Mikhael B shipwreck, were examined in this study. Metallurgical methods comprising visual testing, XRF, multi-focal light microscopy, SEM-EDS analysis and Raman spectroscopy, were used to determine the corrosion products and microstructure of the coins. The analysis results show that the coins were made of copper-lead alloy with a heterogeneous microstructure of bright and dark metal areas. The external surfaces of the coins were mostly composed of oxides and corrosion product compounds rich in Cu, Pb and Sn, while the external dark concretion coating was rich in Si, S, Ca and C compounds. Gradual variation of the composition and structure of the oxides and concretion coating layers was observed.
10.1016-j.micron.2019.102783	6	grain; deformation; strain; strength; dislocation; cu-; tensile; size; ecap; grain size; sfe; ductility; hardening; high; stress	The trade-off between strength and ductility is a long-standing dilemma in metals and alloys. In this study, we fabricated an ultra-coarse-grained (UCG) Cu-6 wt%Al alloy with a coarse-grained (CG) surface layer by surface mechanical attrition treatment. Pre-torsional treatment for 45 degrees, 90 degrees and 180 degrees was conducted on the UCG-CG specimens, and the effects of pre-torsional treatment on the microstructures and mechanical properties of the UCG-CG Cu-6 wt%Al alloy were systematic investigated. It has been shown that the strength and ductility can be simultaneously enhanced via pre-torsional deformation due to the formation of gradient microstructures.
10.1016-j.microrel.2013.05.002	2	corrosion; surface; film; electrochemical; films; spectroscopy; layer; current; solution; potential; resistance; composition; x-ray; ions; showed	The effects of the dry period, temperature and (NH4)(2)SO4 on the electrochemical corrosion behaviour of copper film in printed circuit board (PCB-Cu) under thin electrolyte layer were investigated by electrochemical noise and electrochemical impedance spectroscopy combining with SEM analyses under various periodic wet-dry cycle conditions. Results showed that the corrosion rate of PCB-Cu decreased at the initial stage then increased, and eventually attained a steady state at the last stage, which could be ascribed to the difference of the protective performance of the formed corrosion products. According to the characteristics of the noise potential, each single wet-dry cycle could be divided into three regions. Crown Copyright
10.1016-j.microrel.2017.09.024	2	corrosion; surface; film; electrochemical; films; spectroscopy; layer; current; solution; potential; resistance; composition; x-ray; ions; showed	This study investigated the electrochemical characterizations in the field of wire metallurgy (Pd concentration) and molding compound chemistry (chloride concentration) to find ways to reduce metallic entities' susceptibility to corrosion at ball-pad interfaces. The open circuit potentials and potentiodynamic polarization curves of various metallic entities found in a Cu(Pd)-Al bonding interface were obtained in near-neutral electrolytes of 100 ppm, 20 ppm, and 1 ppm of NaCl in high-purity water. From X-ray diffraction spectra, it was found that Pd could be homogeneously incorporated into Cu9Al4, the Cu-rich intermetallic compound (IMC) also referred to as gamma but not into CuAl2, the Al-rich IMC also referred to as theta for arc-melted specimens. For Cu-Pd alloys, at a given chloride concentration, increasing Pd concentration causes the value of open-circuit potential (E-oc) to increase and corrosion current density (i(corr)) to decrease. Likewise, for a given amount of Pd in Cu-Pd alloy, decrease in the NaCl concentration causes the value of E-oc to increase and i(corr) to decrease. Interestingly, for high concentration of Pd as in the case of Cu-9Pd, E-oc and i(corr) became less sensitive to the NaCl concentrations investigated. This can be attributed to the Pd enrichment on the corroding surface that reduces the anodic dissolution rate of Cu. For Pd-doped gamma intermetallics, increasing Pd concentration causes a systemic increase in the value of E-oc, but at a lower concentration of Pd, the value of i(corr) was increased. The addition of Pd to gamma causes an increase in the cathodic current density due to the high cathodic activity of Pd, while the passivation of Al in gamma reduces the extent of the anodic current density reduction due to the addition of Pd, which leads to a higher value of i(corr) at a low Pd concentration. This is true even when the NaCl concentration is as low as 1 ppm. On the other hand, the influence of NaCl concentration on the E-oc and i(corr) of gamma IMC was always observed, even with Pd addition.
10.1016-j.microrel.2017.12.012	-1		The Cu40Al60 alloy has been developed as the precursor alloy to fabricate narioporous copper (NPC) sheets through chemical dealloying in 1.6 mol/L dilute hydrochloric acid solution at various temperatures. A nano porous structure with uniform pore distribution and size formed after the bath temperature exceeded 80 degrees C. The Cu-Cu interconnection was achieved by inserting the NPC sheet as an interlayer and reflowing without solder under a pressure of 10 MPa. After bonding, the thickness of NPC layer was greatly reduced and the porous structure was densified. The average shear strength of the bondlines was measured to be 22.10 MPa, and the bondlines exhibit a low electrical resistivity of 9.65 mu Omega.cm. The Vickers hardness and shear strength of the bondline increased after aging at 150 degrees C for different time due to the densifled porous structure. This work demonstrated that the NPC sheets can be used to achieve the Cu-Cu interconnection, which is a potential bonding technology for power devices operating at high temperature.
10.1016-j.microrel.2024.115448	-1		With increasing integration of the semiconductor devices, the requirements on size accuracy and surface quality of the lead frame are higher. Cold-rolling and low-temperature aging are usually used in processing of the Cu alloy for lead frame, which generate/eliminate the deformation defects that affect the etched surface morphology and roughness, while the influence mechanisms have not been well revealed. In this study, the CuCrSn alloy was used as the experimental material, which was cold-rolled to different degree and then aged at 450 degrees C for different time, and the microstructures and etched surfaces of the specimens were characterized. The results show that etched surface morphologies of grains with different orientations in the coarse-grained Cu alloy are different. With increasing cold-rolling deformation, the influences of grain orientation become less obvious, and the dislocation groups on the slip planes result in grooves approximately parallel to the rolling direction, meanwhile the surface uniformity are improved and the surface roughness decreases. For the 80 % cold-rolled Cu alloy, the density of grooves decreases with increasing aging time and elimination of the dislocations, and the etched surface roughness decreases firstly and then tends to be stable. The etched surface changes significantly and the surface roughness increase obviously after recrystallization of the specimen.
10.1016-j.microrel.2024.115512	-1		In this study, we introduced trace amounts of silver and nickel into 500 mu m diameter copper wires to form micro-alloyed copper wires used in insulated gate bipolar transistors (IGBT). The addition of silver and nickel enhanced the mechanical properties of the conductors and suppressed the work hardening effect, significantly improving the power cyclic lifetime. Additionally, this study conducted chlorination and high-temperature oxidation test to compare the application characteristics of the heavy micro-alloyed copper wires with pure copper wires, through tensile and bending test, as well as electrical property comparisons. Finally, Cu50Ni (50 ppm Ni) wires were selected and nickel ceramic substrates for wire bonding to evaluate module electrical properties and bonding reliability. In the chloride test, there was no significant pitting corrosion observed in copper wire, and the micro-alloyed copper wire outperformed the pure copper wires in terms of bending lifetime and power cycling performance. In the high-temperature oxidation test, an oxide layer of cuprous oxide formed on the surface of all wires. The pure copper wire exhibited a significant increase in resistance. Notably, the micro-alloyed copper wires had better resistance to oxidation. Regarding wire bonding, the use of Cu50Ni wires and nickel ceramic substrates reduced the diffusion rate of nickel atoms from the substrate to the copper wire, forming a thinner alloy diffusion layer. This prevented electrical degradation and achieved high bonding reliability, especially under higher bonding forces. These findings confirm that micro-alloyed copper wires are suitable for high-power applications.
10.1016-j.mineng.2016.09.023	2	corrosion; surface; film; electrochemical; films; spectroscopy; layer; current; solution; potential; resistance; composition; x-ray; ions; showed	The influence of grinding chemistry on the flotation behaviour of sulphides minerals has been widely studied. However, its influence on partially oxidised sulphide ores is not well documented. Various oxidation events can affect a sulphide ore, either during in situ weathering of an ore body or during the different extraction and processing stages (mining operations, stockpiling, crushing, milling and flotation). In this study, a hypogene copper sulphide ore was artificially oxidised to various lengths of time by percolating a small quantity of acidic ferric sulphate solution inoculated with a mixed bacterial culture through packed columns. For each time interval a series of grinding-flotation tests using different grinding media alloys was completed. The grinding and flotation chemistry were compared and linked to the flotation behaviour of the ore samples. The results reveal that as oxidation progressed the copper metallurgy deteriorated. However, the deleterious effects of oxidation could be partially overcome through the application of the right grinding chemistry.
10.1016-j.molliq.2018.04.020	0	solidification; phase; magnetic; magnetic field; undercooling; field; liquid; separation; peritectic; immiscible; cu-; dendrite; phase separation; microstructure; primary	Cu-Fe alloy processed by conventional preparation methods has serious large-scale composition segregation or spatial separation of individual Cu and Fe phases prior to solidification. For immiscible Cu-Fe alloy, a homogeneous melt is the prerequisite to obtain the subsequent uniform solidification microstructure. In this paper, the uniform metastable immiscible Cu100-xFex alloys (x = 10, 20, 30, 40 wt%) were prepared by arc-melting. The results indicated that with increasing melting times, the initial aggregated Fe-rich melt gradually dissolves into the bulk copper matrix and a homogeneous melt is obtained. Herein a thermodynamic model was constructed to discuss the surface energy driven melting process and the formation of uniform Cu-Fe alloy. During melting process, if the radius of detached liquid Fe-rich droplet is less than the calculated critical radius, the surface energy is high enough to compensate for the partial molar excess Gibbs energy of iron, thereby leading to the spontaneously dissolution of detached liquid Fe-rich droplet into the bulk liquid. As a result, the aggregated Fe-rich melt dissolves step by step eventually forming a homogeneous melt. After subsequent solidification, the immiscible Cu-Fe alloy exhibits homogeneous microstructure. The rapid melt quenching experiments are further performed to validate the proposal model. The results provide strong evidence and support for the surface energy driven dissolution model. The findings give us a basic understanding for the evolution of melting process in other immiscible alloys.
10.1016-j.molliq.2019.111336	0	solidification; phase; magnetic; magnetic field; undercooling; field; liquid; separation; peritectic; immiscible; cu-; dendrite; phase separation; microstructure; primary	In the present study, hypomonotectic Cu-Pb-Sn alloys with Pb-rich secondary phase particles (SPPs) in different morphology were prepared at specific casting temperature (T-q) corresponding to different molar fraction (f(S0)) of the existing primary alpha-Cu (S-0) before pouring. The results show that the SPPs transform from continuously network to independently rod-like morphology and then become abnormally coarsening with increasing T-q. Phase field calculation was carried out to discuss the morphology evolution mechanism of the secondary phase droplets (L-2), which can effectively overcome the experimental difficulty of the investigation about the monotectic reaction with an extremely high reaction rate. It is found that f(s0) can strongly affect such morphology evolution. A relatively high f(s0) corresponding to a lower T-q is proven to promote the formation of network L-2. In contrast, a lower f(s0) corresponding to a higher T-q can promote the formation of rod-like L-2, which is mainly benefitted from the immiscibility of the Cu-rich residual liquid (L-1) and L-2. However, if T-q continuously increases, abnormally coarsening of L-2 will occur mainly through collision and coagulation driven by the Marangoni force and the solidification front's pushing. The coarsening process of L-2 during heating was observed through synchrotron radiation. This work reveals the morphology evolution mechanism of the SPPs in hypomonotectic Cu-Pb-Sn alloy during the monotectic reaction.
10.1016-j.molliq.2019.111543	12	thermodynamic; ternary; phase; data; experimental; equilibria; phase equilibria; liquid; binary; experimental data; calculated; phases; literature; model; calphad	A literature overview of Cu-Ga-In system shows that the information about the liquid phase of this system does not exist. Therefore, using MI-ITC 96 Setaram high temperature drop calorimeter, partial and integral enthalpies of mixing of liquid alloys were determined at first in the binary Ga-In system and next in the ternary Cu-Ga-In system. The ternary liquid alloys were investigated along two cross-sections at three temperatures: 1123 K, 1273 K and 1423 K. Experimental data were used to find ternary interaction parameters by applying the Redlich-Kister-Muggianu model for substitutional solutions, and consequently providing a full set of parameters describing the concentration dependence of the enthalpy of mixing. The experimental data indicate that the heat of mixing in this ternary system is temperature dependent, at least in the measured temperature range. (C) 2019 Published by Elsevier B.V.
10.1016-j.molliq.2020.112930	-1		In the literature, information pertaining to self- and impurity diffusivities of liquid phases for metals, non-metals, etc. is very scarce. The reason for scarcities is diff iculty in performing experiments. The difficulties will be aggravated for pure elements or alloys with high melting points. The advent of efficient computing resources could serve to overcome this experimental snag. Here we report a hybrid methodology of AIMD and CALPHAD approach to obtain an atomic mobility parameter for liquid Cu-Ni and Cu-Si systems in wide composition and temperature ranges. As a part of this hybrid approach, the calculation of self- and impurity diffusion coefficients for Cu-Ni and Cu-Si liquids via ab initio molecular dynamics (AIMD) technique in conjunction with Einstein's diffusion equation is performed. The experimental densities (rho) for Cu-Ni and Cu-Si are used to fix the volume (V) of the super-cell for AIMD simulations. There are total of 64 AIMD simulations in this work. For each binary system, the simulations are performed for eight compositions at four different temperatures. The simulated results at different temperatures are used to extract the activation energies and the frequency factors for different compositions. The CALPHAD-type atomic mobility assessments for the liquid phases of Cu-Ni and Cu-Si are based on the AIMD diffusivities calculations from this work The comparisons of the CALPHAD calculations, experimental measurements, and the AIMD simulations are also given. We believe that this hybrid methodology- AIMD results for CALPHAD-type mobility assessments, will be an interesting addition to the existing literature. It is also highly expected that the presently developed methodology to assess the atomic mobilities is equally valid for other systems.
10.1016-j.molliq.2020.113636	-1		The crystallization mechanism from amorphous matrix during the annealing in Cu-Pd and Cu-Pt alloy systems has been examined by using Molecular Dynamics (MD) simulation with an Embedded Atom Method (EAM). The effects of the addition of Cu on the crystallization have been discussed in terms of radial distribution function, Honeycutt-Andersen (HA) cluster analysis index. Moreover, the crystallization evolution at different annealing temperatures has been obtained using Avrami exponents based on volume-fraction. On the other hand, the crystallization process for different Cu concentrations have been investigated by duster-type index (CTIM) methods enabled to sort the structure of different-type polyhedrons. Our simulation results show that the forming of crystal phase related to the presence of crystal-type polyhedrons and Cu concentration. The crystal phase forming ability increases with Cu content at different annealing temperatures.
10.1016-j.molliq.2021.117936	0	solidification; phase; magnetic; magnetic field; undercooling; field; liquid; separation; peritectic; immiscible; cu-; dendrite; phase separation; microstructure; primary	In this study, the featured local structure units and microstructure evolution of Cu-Fe-P immiscible alloy were investigated. Based on the first principle molecular dynamics simulation, it was revealed that P atoms were inclined to connect with Fe due to higher binding force. The special clusters containing P were determined in the forms of (5Cu + 5Fe) P, (6Cu + 4Fe) P and (5Cu + 5Fe) Pat 1773 K, 1523 K and 1273 K, respectively. Based on the XRD analysis, it was found the Cu-32Fe-8P immiscible alloy was composed of Cu, Fe2P and Fe3P phases. Through a series of the collision, growth and coagulation motions, an evolving core-shell structure was observed in this ternary immiscible alloy. Controlled synthesis of Fe-P spheres with and without pores could be achieved with phase extraction of Cu-32Fe-8P alloys, which provides a novel route for the control formation and the wider potential application of functional phosphides.
10.1016-j.molliq.2021.117958	-1		We demonstrate the atomic-level structural properties of liquid Cu-In alloy as a function of In concentration using Square-Well (SW) model potential function under random phase approximation. It was found that the concentration-dependent structure factor S(k) and its Fourier transform, radial distribution function g(r) are in good agreement with the results obtained by the X-ray diffraction technique. Transport coefficients like diffusion coefficient and shear viscosity of liquid Cu-In alloys were estimated through computed structural functions and SW potential function. Interdiffusion coefficients in the melts were computed by solving the well-known Einstein's equation for Brownian particles with SW pair potential under linear trajectory principal. The composition-dependent shear viscosity is calculated using computed diffusion data in modified Stokes-Einstein (SE) relation. Specifically, we demonstrate a breakdown of SE relation at low In concentration in liquid Cu-In alloy. Using model calculations, we investigate the thermodynamic properties of alloy such as enthalpy of mixing, Gibbs free energy of mixing, and entropy of mixing. The concentration-concentration fluctuation at the zero momentum vector S-cc(0)shows that there is a strong chemical bond between hetero-atoms in the Cu-rich region of liquid Cu-In alloys. It is worth mentioning here that the computed values of S-cc(0), without using any adjusting or experimental parameter are in excellent agreement with experimental values measured by activity data.
10.1016-j.molliq.2022.119344	2	corrosion; surface; film; electrochemical; films; spectroscopy; layer; current; solution; potential; resistance; composition; x-ray; ions; showed	Tetramethylammonium hydroxide (TMAH) is an important constituent used in the post cleaning process of chemical mechanical planarization and lithography; however, its corrosive property causes damage to the Cu metallization. Addition of corrosion inhibitor in the cleaning solution is a promising method to protect Cu. In this study, two corrosion inhibitors, monoethanolamine (MEA) and urea, are used to investigate their synergy on the Cu corrosion protection. Electrochemical and four-point probe methods are adopted to analyze the corrosion behaviors of Cu. Microstructural characterizations of Cu are performed using scanning electron microscopy, transmission electron microscopy, and atomic force microscopy. X-ray photoelectron spectroscopy is used to realize the adsorption behaviors of inhibitors on the Cu surface. The results of corrosion current (I-corr) and charge transfer resistance (R-ct) indicate that addition of MEA and urea at an identical concentration does not produce a typical synergistic effect on the Cu corrosion protection due to mutual interference of two inhibitors. An increase of the MEA concentration overcomes the mutual interference, giving rise to a reduction of I-corr, and an increase of R-ct. The effective retardation of the Cu corrosion is attributed to the sufficiency of inhibitors which can construct a dense protection layer on the Cu surface.
10.1016-j.molliq.2023.121924	2	corrosion; surface; film; electrochemical; films; spectroscopy; layer; current; solution; potential; resistance; composition; x-ray; ions; showed	The high-efficiency and non-toxic inhibitors for copper and its alloys are of great importance for reducing the corrosion rate of copper in aggressive solutions. In this work, the inhibition effect of 2-mercaptopyridine (2-MP) for copper in NaCl aqueous solution was investigated by experiment and theoretical calculation. The comprehensive experimental results showed that the surface of the copper sample was still smooth after 72 h immersion in NaCl solution containing 0.75 g/L 2-MP inhibitor, and the inhibition efficiency could reach 93.27 %. Meanwhile, the Cu-N/S-Cu bonds were detected by X-ray photoelectron spectroscopy and Raman spectroscopy, indicating that the 2-MP inhibitor could adsorb on the copper surface directly. The adsorption of copper by 2-MP is compatible with the Langmuir isotherm adsorption. The difference in reactivity between 2-MP and 4-MP was analyzed by quantum chemistry calculation, while molecular dynamics (MD) simulation results showed that 2-MP has better inhibition performance than 4-MP. Furthermore, the compactness and hydrophobicity of the 2MP molecular layer were increased with a rise in 2-MP concentration, which effectively obstructed the diffusion of the water molecular and prevented the corrosive medium contact with the copper surface.
10.1016-j.molliq.2023.122715	2	corrosion; surface; film; electrochemical; films; spectroscopy; layer; current; solution; potential; resistance; composition; x-ray; ions; showed	Essential oils (EOs) have recently gained attention as sustainable corrosion inhibitors due to their biodegradability, environmental friendliness, low cost, and easy availability. This paper aimed to investigate the synergistic impact of the active green molecules from two essential oils (EO16/EO18) derived from A. visnaga (L.) Lam on the corrosion of Cu-Zn alloy (brass) in a 3% NaCl environment using open circuit potential (OCP), potentiodynamic polarization (PDP), and electrochemical impedance spectroscopy (EIS), surface morphology analysis and computer modelling methods, including density functional theory (DFT) and Monte Carlo (MC) simulations. The electrochemical results demonstrated show that EO18 and EO16 at an ideal concentration of 2 (g/L) and after 6 h of immersion at 298 K, exhibited high inhibition efficiencies (nPDP(%), reaching a maximum of 93.04% and 84.57%, respectively. Moreover, the PDP experiments revealed that EO16 and EO18 acted as mixed inhibitors, with a predominant cathodic inhibitory behavior. Additionally, EO16 and EO18 have strong inhibitory efficacy throughout a wide temperature range (298-338 K), especially EO18. Also, the thermodynamic parameters showed a good relationship with the inhibition efficiency of the EO16/EO18. The examination of surface morphology (SEM/EDX) indicated less degradation of the metallic surface in the presence of both EOs in a corrosive environment, with the formation of resistant protective films, particularly notable for EO18. These findings confirmed the adsorption of EOs molecules onto the active sites of the brass surface, facilitated by the synergistic action of various phytochemical elements, including oxygenated monoterpenes/sesquiterpenes (minor compounds) and major compounds (Croweacin/Linalool). Furthermore, computational investigations utilizing DFT and MC simulations revealed a significant adsorption of EO18/EO16 compounds (both major and minor components) onto Cu (1 1 1) and Zn (110) surfaces. The MC simulation results further demonstrate that the synergistic effect of EO18 compounds on Cu/Zn surfaces results in the formation of stronger and more protective layers compared to the synergistic effect of EO16 compounds. These computational findings align well with the results obtained from experimental inhibition efficiencies. The combination of experimental and computational approaches enhanced our understanding of the corrosion inhibition mechanism and underscored the potential of EOs as sustainable and effective corrosion inhibitors. These findings can serve as a useful guideline for future research aimed at investigating the synergistic inhibitory impact of the components present in the green extracts.
10.1016-j.molstruc.2023.135836	2	corrosion; surface; film; electrochemical; films; spectroscopy; layer; current; solution; potential; resistance; composition; x-ray; ions; showed	This study aimed to investigate the inhibitory effects of two triazole derivatives, 4-amino-3-methyl-1,2,4-triazole-5-thione (MTSNH) and 3-methyl-1,2,4-triazole-5-thione (MTS), as corrosion inhibitors for Cu-30Ni in a 3% NaCl solution. The examination involved the use of various experimental and numerical techniques, including potentiodynamic polarization (PDP), electrochemical impedance spectroscopy (EIS), density functional theory (DFT), Monte Carlo (MC), and molecular dynamic simulations (MD). Additionally, a scanning electron microscope (SEM) coupled with energy-dispersive X-ray analysis (EDX) was utilized to examine the surface morphology of the copper-nickel alloy with and without inhibitors. The results of both stationary and transient tests showed that both derivatives exhibited a good inhibitory effect on the Cu-30Ni surface, with MTSNH demonstrating better inhibition than MTS. The theoretical calculations suggested that both inhibitors were flatly adsorbed, providing better coverage of the copper-nickel surface. As such, the compounds were identified as mixed types since they slowed both anodic and cathodic processes, with anodic predominance. The free adsorption energies of MTSNH and MTS were -40.4 and -35.6 Kj.mol- 1, respectively, indicating that both derivatives were adsorbed through chemisorption on the copper-nickel surface. Furthermore, the adsorption data obtained from the EIS of these compounds corresponded well to the Langmuir adsorption isotherm.
10.1016-j.molstruc.2025.142032	-1		In this study, N-decyl-3-amino-1,2,4-triazole (TN10) was investigated as an eco-friendly corrosion inhibitor for copper-nickel alloy in a 3 % NaCl solution. A combination of experimental techniques, including open-circuit potential (EOCP) measurements, Potentiodynamic Polarization (PDP), Electrochemical Impedance Spectroscopy (EIS), Scanning Electron Microscopy (SEM), Energy-Dispersive X-ray Spectroscopy (EDX), as well as theoretical approaches such as Density Functional Theory (DFT) and Molecular Dynamics (MD) simulations, was employed to provide a comprehensive understanding of TN10 ' s inhibitory behavior and interaction mechanisms. The results revealed that TN10 exhibited excellent corrosion inhibition efficiency, achieving up to 99.17 % at a concentration of 1 mM. PDP curves demonstrated that TN10 acts as a mixed-type inhibitor with predominant anodic behavior. Adsorption studies following the Langmuir isotherm model indicated that TN10 adsorbs onto the metal surface primarily through chemisorption. SEM and EDX analyses confirmed that TN10 forms a protective barrier layer on the Cu-Ni alloy surface. Theoretical investigations using the B3LYP/6-311G++(d,p) provided insights into the electronic properties of TN10. Optimized geometries of TN10-metal complexes were obtained using the DFT/B3LYP/LANL2DZ method. Analysis of binding energies confirmed that these complexes formed strong interactions with the Cu-Ni surface, supporting TN10's high adsorption potential and its effectiveness as a corrosion inhibitor. MD simulations further corroborated the experimental findings and DFT calculations, showing that TN10 adsorbs favorably on Cu-Ni (111) and Cu-Ni (110) surfaces. Radial distribution function (RDF) analysis pointed to a strong chemisorption interaction between TN10 and the metal surfaces (i.e., Cu-Ni (111) and Cu-Ni (110)), reinforcing the inhibitor's efficacy in corrosion protection.
10.1016-j.msea.2003.06.004	4	transformation; martensite; martensitic; phase; shape; beta; memory; shape memory; temperature; temperatures; martensitic transformation; gamma; transformation temperatures; effect; thermal	The evolution with temperature of the elastic constants of the metastable beta phase in a Cu-27.96at%Al-3.62 at% Ni shape memory alloy (SMA) has been studied by resonant ultrasound spectroscopy (RUS). The corresponding elastic constants of this cubic phase have been measured near the martensitic transformation temperature in a single crystal. Above the martensitic transformation temperature, an anomalous behavior has been found in the C'elastic constant which shows a softening as the temperature decreases. The internal friction value Q(-1) has been obtained in this temperature range from the RUS spectra. The mechanisms associated with the Q(-1) increase must be related to {110} shear.
10.1016-j.msea.2003.08.101	4	transformation; martensite; martensitic; phase; shape; beta; memory; shape memory; temperature; temperatures; martensitic transformation; gamma; transformation temperatures; effect; thermal	Ni-Ti and Ni-Ti-Cu alloys were produced by lamination and diffusion processes. The objective of this study is to understand the mechanism of high damping. These alloys undergo phase transformations. When cooling, elastic modulus decreases and internal friction increases at the transformation temperature, and in the martensite region elastic modulus shows the minimum and a relaxation peak or an increase of background damping is observed depending on conditions. Those behaviors are closely related with dislocation motion at twin interface or slip plane in martensite. It has been proposed that the phase stability, modulus drop and damping capacity due to dislocations are categorized by two electronic parameters (B) over bar (0) and (Md) over bar. (C) 2003 Published by Elsevier B.V.
10.1016-j.msea.2003.08.117	4	transformation; martensite; martensitic; phase; shape; beta; memory; shape memory; temperature; temperatures; martensitic transformation; gamma; transformation temperatures; effect; thermal	The purpose of this work is to study the microstructural mechanisms associated with the eutectoid transition in a ternary Cu-12 wt% Al-3 wt% Ni alloy. The samples have been initially annealed at 850degreesC, then slowly cooled down to room temperature. The experiments have been carried out both on cooling and on heating above 500degreesC using isothermal mechanical spectroscopy and X-ray diffraction (fitted with a temperature camera). On heating, a relaxation peak with a high intensity rises up above 600degreesC, then on cooling, the peak totally disappears below 580degreesC, the effect being reproducible. The structural analysis, undertaken in the same temperature domain, has clearly evidenced each step of the evolution, particularly the eutectoid transformation. Consequently, the damping effect seems to be associated to the presence of the high temperature p phase. (C) 2003 Published by Elsevier B.V.
10.1016-j.msea.2003.09.007	-1		Phase transition phenomena in metallic alloys involve complex physical processes occurring over a wide range of temporal, spatial and energy scales. Multiscale modelling is a powerful methodology for understanding these complex systems. In this paper, a multiscale model of grain and pore formation is presented during solidification. At the microscale, a combined stochastic-deterministic approach based on the cellular automata method is used to solve multicomponent diffusion in a three-phase system (liquid, solid and gas), simulating the nucleation and growth of both grains and pores. The impingement of the growing pores upon the developing solid is also solved to predict the tortuous shape of the porosity, a critical factor for fatigue properties. The micromodel is coupled with a finite element method (FEM) solution of the macroscale heat transfer and fluid flow in industrial castings through the temperature and pressure fields. The result model was used to investigate the influence of local solidification time, hydrogen content, local metallostatic pressure and alloy composition upon the predicted grain structure and pore morphology. Comparison of the model predictions to both laboratory and industrial scale castings are presented.
10.1016-j.msea.2003.09.111	4	transformation; martensite; martensitic; phase; shape; beta; memory; shape memory; temperature; temperatures; martensitic transformation; gamma; transformation temperatures; effect; thermal	The atomic order and the precipitation processes of the metastable beta phase during heating in a Cu-13.15 wt% Al-3.25 wt% Ni shape memory alloy processed by powder metallurgy, have been studied by differential scanning calorimetry (DSC), scanning electron microscopy (SEM) and in situ neutron powder diffraction. The transformation temperatures and activation energies have been determined by DSC. The Rietveld analysis performed on the neutron diffraction spectra allows determining the kind of order, the volume fraction of the different precipitated phases and their evolution during heating. Also, the influence of the Ni,Al-rich phase precipitation in the characteristic martensite-austenite transformation has been studied.
10.1016-j.msea.2003.09.116	4	transformation; martensite; martensitic; phase; shape; beta; memory; shape memory; temperature; temperatures; martensitic transformation; gamma; transformation temperatures; effect; thermal	The vibrational behavior of the metastable beta phase near the martensitic transformation (MT) in a single-crystalline Cu-27.96 at% Al-3.62 at% Ni shape memory alloy (SMA) has been studied by resonant ultrasonic spectroscopy (RUS). This technique allows to determine simultaneously all the elastic constants C-ij of anisotropic materials and also the internal friction Q(-1) (C-ij) associated to some particular elastic constant C-ij. The evolution of the resonance frequencies with temperature has been studied and shows that the C and C-44 elastic constants are the magnitudes which control the vibrational response of the beta phase near the martensitic transformation. The internal friction value Q(-1) associated to different resonance modes and their evolution has been measured and correlated to the elastic behavior of the alloy.
10.1016-j.msea.2003.09.117	-1		Cu-Al-Ni shape memory alloys processed by powder metallurgy show very good thermo-mechanical properties, much better than those found in alloys produced by conventional casting. In this paper, we present the microstructural characterisation of these powder metallurgy alloys in order to find the microscopic mechanisms, linked to the powder metallurgy processing method, which are indeed responsible of such good thermo-mechanical behaviour. Electron microscopy studies [scanning electron microscopy (SEM), electron backscatter diffraction (EBSD) and transmission electron microscopy (TEM)] show that powder metallurgy processing creates a sub-grain structure characterised by the presence of low angle sub-boundaries. These sub-boundaries are found to be lying on {110} and {112} lattice planes and are composed by an arrangement of superdislocations. These sub-boundaries may improve ductility in two ways: acting as a sink of dislocations which promotes plastic deformation and decreasing stress concentration at grain boundaries. Moreover, since sub-boundaries act as weak obstacles for the movement of martensite plates, the improvement on ductility is accomplished by an adequate thermo-mechanical behaviour. (C) 2004 Published by Elsevier B.V.
10.1016-j.msea.2003.10.086	11	glass; bulk; metallic; bulk metallic; gfa; bmg; glassy; metallic glass; ability; bulk metallic glass; amorphous; addition; crystallization; mm; glass-forming	We report about the microstructure and the mechanical properties of slowly cooled Zr-Nb-Cu-Ni-Al alloys with a glassy or a nanocrystalline matrix and ductile bee precipitates. These alloys exhibit significantly improved mechanical behavior compared to monolithic glass, because the in situ formed composite undergoes work hardening and plastic deformation prior to failure. Changes in composition and cooling rate lead to different volume fractions and dendrite sizes of the bee phase and, hence, to different values of yield strength, elastic and plastic strain. The glassy or nanocrystalline structure of the matrix influences mainly the elastic strain limit of the composites. This opens the possibility of obtaining tailored mechanical properties and could extend the range of industrial applications of such materials.
10.1016-j.msea.2003.10.092	-1		The crystallisation behaviour in the Cu60Zr30Ti10 alloy was studied. The as-quenched Cu60Zr30Ti10 alloy consists of homogeneously dispersed nanocrystals in the glassy matrix. Two metastable crystalline phases appear prior to the precipitation of equilibrium phases, which correspond to the three exothermic peaks in the DSC curve. After the first exothermic reaction, the nanometer-sized CuZr phase is precipitated in the glassy matrix. In the second exothermic peak, the CuZr phase transforms to a metastable cubic phase with a large lattice parameter of 1.265 nm. Finally, this metastable phase is decomposed to Cu10Zr7, Cu8Zr3 and Cu3Ti2 equilibrium phases. The Cu10Zr7 and Cu8Zr3 phases contain Ti while the Cu3Ti2 phase contains Zr. (C) 2003 Published by Elsevier B.V.
10.1016-j.msea.2003.10.122	-1		Many technical materials contain inclusions or precipitates, mainly for improving their mechanical properties, but which may also arise from processing. A rather new development is the production of particle-strengthened material directly from the melt. The distribution of the particles in the solidified melt is determined by the interaction of the particles with the advancing solidification front: (i) The particles are pushed by the solidification front and are entrapped in the last solidifying part of the melt. (ii) In the case of dendritic solidification, particles are trapped in the interdendritic region. (iii) The solidification front engulfs the particles and they are embedded homogeneously into the alloy. An important experimental parameter, which determines the governing mechanism of the interaction, is the velocity of the solidification front. It can be measured and varied widely by undercooling the alloys containerlessly in an electromagnetic levitation facility. Due to the high undercooling level the microstructure is frozen in instantaneously by rapid solidification and is accessible for post-mortem metallographic investigation. In the present paper first solidification experiments are reported for the systems Ni + Ta2O5, Cu + Ta2O5 and Cu50Ni50 + Ta2O5
10.1016-j.msea.2003.10.306	-1		Constant-stress creep experiments were conducted on extruded Cu-8 Cr-4 Nb (GRCop-84) from 0.57 to 0.79 T-m, with observed strain rates spanning over four orders of magnitude. GRCop-84 is composed of approximately 14 vol.% Cr2Nb distributed in sizes ranging from approximately 30 nm to 0.5 mum in a matrix of pure copper with a grain size of approximately 1-3 mum. This high-strength alloy exhibits creep curves with a standard pure metal-type appearance and true failure strains typically in excess of 10%. The Monkman-Grant relationship is obeyed with a slope of -1.08. Computation of activation energies between neighboring isotherms yields an average value of 287 +/- 14 kJ/mol. Despite apparent power law creep behavior within an isotherm, a master plot of temperature compensated strain rate ( epsilon/exp[-Q/RT]) versus temperature compensated stress (sigma/G) demonstrates that most of the data are above power law breakdown, consistent with sigma/G>10(-3). A hyperbolic sine model facilitates interpolation on this master plot to stresses and/or temperatures where experimental data do not exist. Neither the threshold stress model nor the dislocation detachment model applies to GRCop-84 under these creep conditions.
10.1016-j.msea.2003.10.347	4	transformation; martensite; martensitic; phase; shape; beta; memory; shape memory; temperature; temperatures; martensitic transformation; gamma; transformation temperatures; effect; thermal	Single crystals of 82.5 wt%Cu-13.5 wt%Al-4 wt%Ni which present the beta'(18R) thermally induced martensitic transformation after quenching from 1120 K, were submitted to mechanical tests in the compression mode at different temperatures. The studied temperatures were chosen between M-f and A(f) in order to have the sample completely in beta' martensitic phase or in a mixture of beta' and beta parent phase before applying stress. Under compression the gamma' (2H) martensite is induced in both cases. From the sigma-epsilon curves, the critical stresses (sigma(c)) have been determined. The sigma(c)-T diagram shows a linear decrease of the stress (in absolute value) when increasing the temperature, contrary to the well known increase of absolute value of critical stress with the temperature when the gamma' martensite is induced from the austenitic phase. The dsigma(c)/dT value obtained from the sigma-epsilon curves has been compared with that calculated from the Clausius-Clapeyron equation by combining the entropy change DeltaS(beta'-gamma'), calculated from calorimetric runs for the beta <----> beta' and beta <----> gamma' transformations, and the experimental strain data. In what concerns strain values, it has to be considered that when applying stress on the sample in beta' martensite two processes occur: the deformation of the thermally induced martensite in the sense of the applied stress (variant reorientation) and the formation of the gamma' martensitic phase. A set of experiments done at constant temperature up to different strain levels followed by calorimetric runs allowed us to separate both strain components and to obtain reasonably good agreement between the theoretical and experimental dsigma(c)/dT values.
10.1016-j.msea.2003.10.348	4	transformation; martensite; martensitic; phase; shape; beta; memory; shape memory; temperature; temperatures; martensitic transformation; gamma; transformation temperatures; effect; thermal	The aim of this study is to analyze the martensitic transformation in a shape memory alloy during a superelastic loading, focusing on internal strains, stresses and phases fractions. The behavior of the austenite phase is studied by X-ray diffraction stress analysis during in situ tensile test at room temperature. Both single-crystal and polycrystal samples have been investigated. The results are discussed with the aim to correlate the microstructural variations with the local stress state evolution in the austenitic phase while variants of martensite form and develop during a superelastic loading.
10.1016-j.msea.2003.10.351	4	transformation; martensite; martensitic; phase; shape; beta; memory; shape memory; temperature; temperatures; martensitic transformation; gamma; transformation temperatures; effect; thermal	A Cu-24.0 at% Al-2.2 at% Ni-0.5 at% B shape memory alloy was investigated experimentally under uniaxial tensile stress (sigma) up to 10MPa. Transformation temperatures and transformation strains as a function of a were evaluated from the simultaneously measured temperature-elongation and temperature-resistance curves. Using appropriate analysis [Philos. Mag. B 82 (2002) 105; Scripta Mater. 43 (2000) 691; J. Phys. IV 11 (2001) Pr8], it is possible to determine the stress dependence of the volume derivatives of the elastic and dissipative free energies at the start and finish points of the forward and reverse transformations from the measured transformation temperatures and strains. From our experimental data, the above volume derivatives were calculated as a function of stress. The dissipative contributions both of the forward and reverse transformations increase with increasing stress. In case of elastic contributions, the difference between the forward and reverse transformation values as well as their decreasing tendency with increasing stress was clearly proved.
10.1016-j.msea.2003.10.352	4	transformation; martensite; martensitic; phase; shape; beta; memory; shape memory; temperature; temperatures; martensitic transformation; gamma; transformation temperatures; effect; thermal	Cu-AI-Be beta'(1) martensite exhibits different levels of stabilization after various heat treatments (direct quenching into martensite, step-quenching, air cooling). However, this stabilization does not demonstrate time dependence upon martensite ageing at around room temperature, and can be considered as instantaneous. Cu-Al-Be martensite also stabilizes as a result of deformation of martensite starting from rather low values of prestrain. The conclusion is drawn that Cu-Al-Be alloy exhibits purely mechanical stabilization both after heat treatments and upon plastic deformation due to jamming the motion of interfaces. Non-elastic accommodation of transformation strain under a combined action of transformation stress and residual thermal stresses during the first direct martensitic transformation (MT), and kinetic stabilization due to sweeping-up of quenched-in defects during the martensitic transformation are considered as possible mechanisms of the observed instantaneous stabilization registered after heat treatment. (C) 2003 Published by Elsevier B.V.
10.1016-j.msea.2003.11.069	4	transformation; martensite; martensitic; phase; shape; beta; memory; shape memory; temperature; temperatures; martensitic transformation; gamma; transformation temperatures; effect; thermal	Martensitic stabilisation phenomenon in the copper-based shape memory alloys has been invariably related to thermomechanical treatments and post-quench history. This phenomenon degrades shape memory properties and reduces their potential for industrial applications. In the present work, superelastic tests in a single crystal of Cu-Al-Be alloy were realised to study the martensitic stabilisation processes. Direct quenched samples have been studied in a special apparatus which allows to measure simultaneously stress-strain and electrical resistance. Two experimental procedures were used: superelastic cycles (8% strain) and ageing in mixed state. In the second test, the sample is submitted to a 4% strain by superelasticity which leads to a mixture of beta-phase and single variants of martensite separated by parallel interfaces. After 24 h, the sample is strained up to 8% and finally the stress is removed leading to a total strain recovery. The stress-strain as well as the resistivity curves show a very different behaviour between the volume fraction which have been aged in the martensitic state and the one aged in the beta-phase state. The results are discussed in terms of thermal treatment influence and stabilisation processes.
10.1016-j.msea.2003.11.092	-1		The atomistic mechanisms of plastic deformation in amorphous metals are far from being understood. We have derived potential parameters for molecular dynamics simulations of Mg-Cu amorphous alloys using the Effective Medium Theory. We have simulated the formation of alloys by cooling from the melt, and have used these glassy configurations to carry out simulations of plastic deformation. These involved different compositions, temperatures (including zero), and types of deformation (uniaxial strain/pure shear), and yielded stress-strain curves and values of flow stress. Separate simulations were carried out to study specific features in the stress-strain curves associated with transitions involving internal rearrangements of atoms. Energy barriers were calculated as a function of stress, as was the plastic strain associated with events. The latter leads to a characteristic volume of an event which seems to correspond with the derivative of the barrier with respect to stress.
10.1016-j.msea.2003.12.090	6	grain; deformation; strain; strength; dislocation; cu-; tensile; size; ecap; grain size; sfe; ductility; hardening; high; stress	Orientation-controlled copper bicrystals with dispersed SiO2 particles were cyclically deformed at 673 K in vacuum. Although the fatigue lives of all the bicrystals increased monotonically with decreasing stress amplitude at a higher stress amplitude region, some of them showed discontinuous and abrupt life shortening at a lower stress amplitude region. This transition of the cyclic creep behaviour was brought about by the occurrence of brittle intergranular fracture caused by grain-boundary sliding (GBS) and particle dragging by GBS to form the elongated voids. At the lower stress region, such voids were easily formed by GBS. At the higher stress region, however, grain-boundary steps that densely formed by plastic deformation effectively suppressed GBS, resulting in the absence of brittle intergranular fracture. The mechanism of grain-boundary and stress-amplitude-dependent fracture behaviour will be discussed in relation to GBS.
10.1016-j.msea.2004.02.001	4	transformation; martensite; martensitic; phase; shape; beta; memory; shape memory; temperature; temperatures; martensitic transformation; gamma; transformation temperatures; effect; thermal	Effects of plastic prestrain and of different heat treatments on the stabilization of martensitic beta(1)' crystals of a Cu-Al-Be alloy have been studied. Directly quenched and plastically prestrained samples (subjected to preliminary heat treatments, suppressing the stabilization) undergo the reverse martensitic transformation in two distinct stages. The first stage is a partial bulk transformation which exhibits typical stabilization properties: shift and broadening of the reverse transformation range. The rest of the martensite is hyperstabilized both in prestrained and quenched samples and retransforms through renucleation of lamellar beta-phase at temperatures approximately 300 K above the nominal reverse transformation. In prestrained samples, the magnitude of shift and broadening of the first stage of the reverse transformation depends on the degree of plastic prestrain, whereas the renucleation of beta-phase occurs at nearly constant temperatures, independent of the amount of prestrain. Relative fractions of martensite retransformed to the beta-phase through the normal mechanism of reverse motion of variant interfaces and through renucleation of beta-phase depend on the degree of prestrain. Stabilization registered after different heat treatments is virtually instantaneous and it is not related to martensite aging. The conclusion is drawn that heat treatment-induced stabilization in Cu-Al-Be beta(1)' martensite is athermal, not related to diffusion-controlled processes during aging of martensite, but associated with jamming the motion of interfaces, similar to prestrain-induced stabilization. Plausible mechanisms of athermal stabilization registered after heat treatment are discussed.
10.1016-j.msea.2004.02.067	5	materials; thermal; heat; properties; material; welding; sintering; fusion; strength; laser; heat sink; thermal conductivity; mechanical; sink; manufacturing	A novel technique, impulse atomization, has been used for spray deposition. This single fluid atomization technique leads to different spray characteristics and impact conditions of the droplets compared to gas atomization technique which is the common technique used for spray deposition. Deposition experiments with a Cu-6Sn alloy were conducted to evaluate the appropriateness of impulse atomization to produce dense material. Based on these experiments, a model has been developed to simulate the thermal history and the local solidification rates of the deposited material. A numerical study shows how different cooling conditions affect the solidification rate of the material.
10.1016-j.msea.2004.05.036	-1		Bicrystals of a Cu-2.0 wt% Sb alloy with different [001] symmetric tilt boundaries were tensile tested at several temperatures from 77 to 743 K. The dependence of Sb segregation level at [001] tilt boundaries on the misorientation angle also was examined by energy-dispersive X-ray spectroscopy. The fracture behavior was sensitive to the misorientation angle and test temperature. Both the fracture behavior at 77 K and the Sb segregation level showed a good correlation with the gram-boundary energy of pure Cu. The higher the grain-boundary energy, the higher the Sb segregation level and the higher the degree of grain-boundary embrittlement.
10.1016-j.msea.2004.08.005	0	solidification; phase; magnetic; magnetic field; undercooling; field; liquid; separation; peritectic; immiscible; cu-; dendrite; phase separation; microstructure; primary	Laser surface remelting experiments were conducted on Cu-26.6, 27.3 and 31.4 wt% Mn alloys to investigate their microstructure evolution and growth rate under an ultra-high temperature gradient. The experimental results showed that the microstructure of Cu-26.6 wt% Mn alloy changed from cell to dendrite, super-fine cell and segregation-free solid with increase of growth rate. No dendrite growth appeared in the whole range of growth rate for Cu-27.3 wt% Mn and Cu-31.4 wt% Mn alloys which fully grew in cellular form. The elongated cellular structure appeared before high-velocity absolute stability was reached in Cu-31.4% Mn alloy, which showed a symmetric behavior in the morphological transformation in both limits of the absolute stability and the low rate interface morphological stability. The critical rates of absolute stability for Cu-31.4, 27.3 and 26.6 wt% Mn alloys were 113.3, 212.6 and 260.5 mm/s, respectively, which was in reasonable agreement with those predicted by M-S theory.
10.1016-j.msea.2004.08.058	-1		The hot mechanical behaviour and microstructure of Cu-5 vol.% TiC, Cu-5 vol.% ZrO2 and Cu-2.5 vol.% TiC-2.5 vol.% ZrO2 alloys prepared by reaction milling were studied. After a test of 1 h annealing at 1173 K, the Cu-5 vol.% ZrO2 alloy presented the lower softening resistance to annealing, while the other two ones kept their initial room-temperature hardness (about 2 GPa). Hot-compression tests at 773 and 1123 K, at initial true strain rates of 0.85 x 10(-3) and 0.85 x 10(-4) s(-1) were performed. The Cu-2.5 vol.% TiC-2.5 vol.% ZrO2 and the Cu-5 vol.% ZrO2 alloys were the strongest and softest materials, respectively. Moreover, by electron microscopy, nanometric TiC and micrometric particles were detected in the Cu-5 vol.% TiC and Cu-5 vol.% ZrO2 alloys, respectively. A possible explanation for the observed behaviour of these materials is proposed. In the compression tests, it was also found that strain rate has a low effect on flow stress, as it has been previously observed by various authors in dispersion-strengthened alloys deformed at high temperatures.
10.1016-j.msea.2004.09.068	4	transformation; martensite; martensitic; phase; shape; beta; memory; shape memory; temperature; temperatures; martensitic transformation; gamma; transformation temperatures; effect; thermal	Present study concerns the effect of trace addition of Ti on the factors governing the microstructural evolution in Cu-Zn-Al shape memory alloy during different thermal treatments. It has been revealed that trace addition of Ti has significantly reduced the transformation temperatures. This in turn, has reduced the susceptibility to microstructural degradation induced by the ageing effect. It has been shown that Ti forms fine precipitate at the beta-phase temperature, which do not contribute to the processes related to the degradation of shape memory effect, rather aids in the nucleation of favorable martensite variants. Moreover, addition of Ti has led to a finer grain size of the alloy due to the pinning effect of the precipitate along with the reduced solute drag.
10.1016-j.msea.2004.10.001	-1		The lattice parameter of Cu substitutional solid solution-alpha-phase-has been studied in relation with the solute content. The investigation was conducted on pure binary Cu-Sn, industrial Cu-Sn-Zn alloys and archaeological bronzes. Lattice parameters and elemental compositions of the alpha-phase have been determined by X-ray diffraction and X-ray spectrometry. A linear relation between the unit cell constant and the atomic tin equivalent content in the alpha-phase has been evidenced and characterised, in fair agreement with Vegard's law. Addition of lead and trace elements has no significant effect on the results. Therefore, the tin equivalent content of the alpha-phase can be determined from XRD evaluation of the lattice parameter. As a consequence, a new approach is proposed for setting composition standards in alpha-(Cu-Sn) and alpha-(Cu-Sn-Zn) bronzes and application to characterization of ancient bronzes is discussed.
10.1016-j.msea.2004.10.015	4	transformation; martensite; martensitic; phase; shape; beta; memory; shape memory; temperature; temperatures; martensitic transformation; gamma; transformation temperatures; effect; thermal	A beta Cu-Zn-Al, with and without TiB addition as grain refining, shape memory alloy has been investigated with detail in order to evaluate the influence of this grain refiner on some alloy properties. For Cu-Zn-Al-Ti-B, on isothermal aging in the range of 523-773 K, the beta phase was found to decompose by the precipitation of gamma phase followed by a phase and eutectoid decomposition. The gamma precipitate volume fraction evolution as a function of aging time has been determined and the TTT diagram for the precipitation of both gamma and of phases has been constructed. Besides, nonisothermal aging behavior has been investigated by means of differential scanning calorimetry for Cu-Zn-Al and Cu-Zn-Al-Ti-B alloys.
10.1016-j.msea.2004.12.030	-1		In order to assess the material behaviour of brass during metal cutting processes, dynamic shear tests are carried out with effective strain rates between 1 x 10(-3) and 2 x 10(5) s(-1) The high strain rates are realized in hat-shaped shear specimens using a split Hopkinson compression-bar configuration. Different alpha- and alpha/beta-brasses with and without lead are tested in annealed and strain-hardened condition. In the range of high stain rate, the material behaviour is governed mainly by two contrary effects: first, the adiabatic character behaviour of the high-speed deformation process, which promotes deformation localization: and second, the increased strain-rate sensitivity, which has a stabilizing effect on the deformation process and reduces the strain concentration. Both the effective strain at fracture and the deformation work per unit volume are considered as indicators for the formation of continuous chips during metal cutting. Beyond 10(4) s(-1), both values are approximately proportional to the strain rate. The dependence of chip fragmentation on main cutting parameters is explained by these functions.
10.1016-j.msea.2005.04.044	-1		Spherical Cu54Ni6Zr22Ti18 metallic glass powders were prepared using a high-pressure gas atomizer, followed by consolidation using spark plasma sintering (SPS) process. The glass forming ability of both powders as atomized and bulks as SPSed was investigated by X-ray diffractometer (XRD) and differential scanning calorimeter (DSC) as a function of powder size distribution. The bulk maintains the amorphous structure even after the thermal consolidation. The compressive strength was increased as the powder size decreased due to an increased density. The compression tested BMG presents a fracture pattern occurred along the maximum shear plane declined similar to 45 degrees to the loading direction.
10.1016-j.msea.2005.05.009	1	shape; memory; shape memory; damping; martensite; martensitic; damping capacity; transformation; capacity; strain; superelasticity; temperature; cu-al-mn; shape memory effect; effect	The stress-induced martensite transformation in Cu-18Al-8.7Mn-3.4Zn-0.1Zr alloy (at%) has been studied by means of tensile test, electrical resistivity curve measurement, in situ metallographical observation, X-ray diffraction and TEM observation. By applying stress to the uniform 01 matrix, two or more groups of differently oriented martensitic variants are stress-induced inside one grain. With further increase of stress, they coalesce into a single oriented variant martensitic phase or form complicated cross-like configuration. The elongation and the ultimate tensile strength of the tested CuAlMnZnZr alloy as-quenched in the ordered P 1 phase are 11% and 550 MPa, respectively. For the alloy, there is a characteristic deformation temperature (between M-s + 10 degrees C and M-s + 60 degrees C) and a strain range (between 6.5 and 9.0%). In this case, deformation can effectively increase the transformation hysteresis (more than 90 degrees C), while the strain recovery ratio remains practical high (more than 3.7%).
10.1016-j.msea.2005.05.072	6	grain; deformation; strain; strength; dislocation; cu-; tensile; size; ecap; grain size; sfe; ductility; hardening; high; stress	The influence of cold rolling to 50, 75 and 90% reduction on the age hardening behaviour of Cu-4Ti-1Cr alloy has been investigated by hardness and tensile tests and optical as well as transmission electron microscopy. Hardness of Cu-4Ti-1Cr alloy increased from 222 HV in solution treated condition to 416 HV with 90% cold work and peak aging. Cold deformation reduced the peak aging temperature from 450 degrees C for the undeformed alloy to 400 degrees C for cold deformed alloys. The yield strength (YS) and ultimate tensile strength (UTS) of the alloy with 90% cold work followed by peak aging at 400 degrees C were found to be 1165 and 1248 MPa, respectively. The microstructure of the deformed alloy exhibited elongated grains and deformation bands. The maximum strength on peak aging was obtained due to precipitation of ordered, metastable and coherent beta(1), Cu4Ti phase in addition to high dislocation density and deformation twins. Overageing of the alloy resulted in reduced hardness and strength due to the formation of incoherent and equilibrium beta, Cu3Ti phase in the form of cellular structure. However, the morphology of the discontinuous precipitation was changed to globular shape with high deformation.
10.1016-j.msea.2005.06.017	-1		The effect of the sample preparation method on the observation of amorphous structure in glass forming Cu-Zr, Cu-Zr-Ti and Cu-Zr-Ti-Ni alloys (Cu-Zr-based alloys) using transmission electron microscopy (TEM) has been investigated. The result shows that the selection of a proper sample preparation method is crucial in observing artifact-free amorphous microstructure, since Cu-Zr-based alloy is readily oxidized in air atmosphere. Electro-chemical thinning or electro-chemical thinning followed by ion milling causes oxide (Cu2O and CuO) contamination on the surface of the sample. Only low-energy ion milling with liquid nitrogen cooling can result in the observation of a fully amorphous structure. The exposure time of the thin foil sample in air before TEM examination should be minimized to observe the microstructure without contamination.
10.1016-j.msea.2005.06.043	-1		In this study, Cu-based bulk amorphous alloy billets were fabricated by a powder metallurgy route, and their microstructure and mechanical properties were investigated. Rapidly solidified amorphous powders were produced by a conventional N-2 gas atomization method. In order to consolidate amorphous alloy billets, a spark plasma sintering (SPS) equipment was set up, and variables for hot consolidation were established. Using the consolidation temperature of 480 degrees C under a pressure of 80 MPa, good quality amorphous alloy billets having very few micropores or crystalline phase particles were obtained. Compressive strength of the billet was 1.8 GPa, which was about 6% lower than that of the cast amorphous alloy billet. This reduction was associated with the presence of few micropores, crystalline phase particles and thin oxide layers formed along prior powder boundaries in the billets. Amorphous matrix composite billets containing Cu particles homogeneously distributed in the amorphous matrix were successfully fabricated by the SPS consolidation. These composite billets showed a considerable amount of plastic strain because of the presence of ductile Cu particles, although their compressive strength was lower than that of the amorphous alloy billets.
10.1016-j.msea.2005.08.114	-1		The paper presents the results of electron microscopy investigations of the defect structure evolution and the phase transformation of ultra fine-grained (UFG) Cu and Cu-Al-O alloy. The UFG Cu was prepared using the equal-channel angular (ECA) pressing method. The Cu-Al-O alloy was synthesized by mechanical milling and subsequent high temperature pressing. The initial grain size of the materials was 200 nm. The grain and dislocation structures were investigated qualitatively and quantitavely. In the Cu alloy, deformation twinning was revealed to occur in coarse grains together with slip deformation. The evolution of grain and dislocation micro structure in the presence or absence of solid solution and of dispersion hardening is analyzed, and differences are assessed.
10.1016-j.msea.2005.08.122	-1		A Cu-Fe(10 vol.%) composite material was fabricated by the cold drawing process and then processed by high-pressure torsion (HPT). The resulting nanostructure was investigated by scanning electron microscopy, transmission electron microscopy and three-dimensional atom-probe analysis. This paper describes the fabrication of the Cu-Fe composite material and then the evolution of the microstructure during the HIPT process. Experimental data reveal a strong decrease of the grain size in the range of 10-50 nm, which is much smaller than in pure iron or pure copper processed by HPT. A significant interdiffusion of Cu and Fe was also revealed by means of the atom-probe investigations. This mechanical alloying is discussed as a consequence of vacancies induced by severe plastic deformation.
10.1016-j.msea.2005.09.099	11	glass; bulk; metallic; bulk metallic; gfa; bmg; glassy; metallic glass; ability; bulk metallic glass; amorphous; addition; crystallization; mm; glass-forming	(Cu47Zr11Ti34Ni8)(99.5)M-0.5 (M = 0, Cr, Mo and W) bulk metallic glasses (BMGs) with diameter of 3 mm were prepared by water-cooled copper mold casting. The effect of the addition of a small amount of Cr, Mo or W on thermal property and corrosion resistance of the base BMG (i.e., Cu47Zr11Ti34Ni8) was investigated by means of XRD, DSC, electrochemical polarization and weight loss measurements. It was found that the addition of the elements led to a significant decrease in glass transition temperature (T-g) and crystallization temperature (T.) of the base BMG. As the results, the supercooled liquid region, Delta T-x = T-x1-T-g, slightly decreased for the BMG containing Cr, but increased for the BMGs containing Mo and W with a maximum value of 66K for (Cu47Zr11Ti34Ni8)(99.5)W-0.5 bulk metallic glass. Electrochemical measurements on various Cu-based BMGs were conducted in 1N H2SO4 and 1N NaOH aqueous solutions, respectively, at room temperature. It showed that the BMGs with a small amount of Cr, Mo or W exhibited a superior corrosion resistance in the two electrolytes as compared with the base alloy. (Cu47Zr11Ti34Ni8)(99.5)Mo-0.5 BMG exhibited the greatest corrosion resistance, as indicated by the lowest passive current density and the lowest corrosion rate. The effect of the element addition on thermal stability and corrosion behavior has been tentatively discussed.
10.1016-j.msea.2005.11.008	-1		Experiments were conducted to evaluate the influence of equal-channel angular pressing (ECAP) on the magnetic properties of a Cu-1.8 wt% Co alloy containing 0.2 wt% Cr which forms ferromagnetic Co-rich precipitates in the Cu matrix after aging treatment. Coherent face-centered-cubic precipitates were formed by isothermal aging at 873 and 1073 K for 259 ks. The two different aging temperatures gave precipitates of different sizes, which were expected to show either single-domain or multidomain structure. In the case of small precipitates, one pass of ECAP was effective to improve coercivity, but further pressings tended to decrease coercivity and saturation magnetization due to random orientation and dissolution of the precipitates. In the case of large precipitates, shape change to increase coercivity is difficult. Saturation magnetization was increased by the demagnetizing effect of the precipitates. Electron holography provided the quantitative magnetization measurements for rounded cubic and elongated Co precipitates, indicating the increased in-plane magnetization of the elongated precipitate due to the demagnetizing effect as a result of deformation.
10.1016-j.msea.2005.12.042	4	transformation; martensite; martensitic; phase; shape; beta; memory; shape memory; temperature; temperatures; martensitic transformation; gamma; transformation temperatures; effect; thermal	Isothermal stress-induced transformations in Cu-13.1Al-4.0Ni (wt%) single crystal wires were studied up to an overall strain of 8.62% and cycled until stabilization at test temperatures in the range, 25-175 degrees C, after the material had been heated from room temperature. A total of 26 cycles were needed for stabilization. A partial phase diagram of the cycled material is then developed. A second set of tests on the same material was carried out by heating the material to 175 degrees C and then cooling it to the test temperature, prior to the mechanical tests. A total of 18 cycles were needed for stabilization. Two-way shape memory strain started to accumulate from the 39th mechanical cycle, rising to as high as 3% at the end of the 44th cycle. No plastic strain was observed during the entire sequence of 44 cycles.
10.1016-j.msea.2005.12.058	4	transformation; martensite; martensitic; phase; shape; beta; memory; shape memory; temperature; temperatures; martensitic transformation; gamma; transformation temperatures; effect; thermal	In order to study the reverse transformation dynamics of Mn-Cu alloys with deformed martensitic phase, the temperature dependence of internal friction (IF) is measured under various heating rates and vibration frequencies, while the deformed martensite microstructure of the alloy is observed with scanning electron microscopy and electron backscatter diffraction at room temperature. It is found that variant reorientation of twinning martensite is induced by the applied tensile stress through detwinning and diminishing of unfavorable orientation. Meanwhile, the IF peak occurring during the reverse transformation shows different nonlinear relationships to heating rate and vibration frequency, when the martensite microstructure is deformed to different plastic strains. The coefficient n and l describing the transformation dynamics are determined from the heating rate and frequency dependent IF peaks, and the variation as well as the physical meaning of the coefficients corresponding to the changes in martensite microstructure are discussed. (c) 2006 Published by Elsevier B.V.
10.1016-j.msea.2005.12.066	4	transformation; martensite; martensitic; phase; shape; beta; memory; shape memory; temperature; temperatures; martensitic transformation; gamma; transformation temperatures; effect; thermal	The influence of precipitation processes on the characteristics of the martensitic transformation in two Cu-Al-Ni shape memory alloys processed by powder metallurgy has been analyzed. The Cu-14.37Al-42M (wt%) alloy with a hypereutectoid composition undergoes a low-temperature martensitic transformation, M-s < 100 degrees C. On the other hand, the Cu-14.15Al-3.25Ni (wt%) near eutectoid composition undergoes a high-temperature martensitic transformation, M-s > 110 degrees C. The evolution of the kind of induced martensite, hysteresis and transformation temperatures as a function of thermal history has been studied by differential scanning calorimetry. Also, resonant ultrasound spectroscopy allows changes to be monitored of elastic constants during the evolution of the microstructure. Finally, a comparative analysis of the behavior of both alloys has been made.
10.1016-j.msea.2005.12.102	11	glass; bulk; metallic; bulk metallic; gfa; bmg; glassy; metallic glass; ability; bulk metallic glass; amorphous; addition; crystallization; mm; glass-forming	Effects of the addition of a small amount of Sn and/or Si on glass-forming ability and mechanical properties of Cu5OZr42.Ti-5(7.5) (at%) bulk metallic glass were studied. The critical diameter for glass formation is 5 mm for Cu50Zr42.5Ti7.5 alloy, and increases to 6 mm for (Cu0.5Zr0.425Ti0.075)(99)Sn-1 and (Cu0.5Zr0.425Ti0.075)(99)Si-1 alloys and 7mm for (Cu0.5Zr0.425Ti0.075)(98.8)Sn0.6Si0.6. In uniaxial compression, (Cu0.5Zr0.425Ti0.075)(99)Sn-1 and (Cu0.5Zr0.425Ti0.075)(98.8)Sn0.6Si0.6 bulk metallic glasses exhibit large plasticity of 8% and 5.3%, respectively, while the limited plasticity of 0.5% and 0.6% is obtained for Cu50Zr42.5Ti7.5 and (Cr0.5Zr0.425Ti0.075)(99)Si-1 bulk metallic glasses.
10.1016-j.msea.2006.01.105	4	transformation; martensite; martensitic; phase; shape; beta; memory; shape memory; temperature; temperatures; martensitic transformation; gamma; transformation temperatures; effect; thermal	An analysis of the microstructure evolution during super-elastic cycling has been performed by transmission electron microscopy (TEM) in order to understand the physical mechanism responsible for the thermo-mechanical properties evolution, as well as the martensitic transformation ageing. Particularly, in this work we have studied the super-elastic effect in Cu-Al-Ni shape memory alloys by in situ TEM experiments. The bright field images and diffraction patterns have allowed us to determine, during the transformation, the kind of nucleated martensite variants and their relative orientations. Finally, we have analysed the super-elastic effect on the dislocation microstructure and on the transformation temperatures.
10.1016-j.msea.2006.02.074	4	transformation; martensite; martensitic; phase; shape; beta; memory; shape memory; temperature; temperatures; martensitic transformation; gamma; transformation temperatures; effect; thermal	The mechanical hysteresis and the large recoverable deformation that shape memory alloys have in the pseudoelastic regime make them attractive for damping devices, The diffusion effects on the transformation temperatures in Cu-Al-Be are presented and evaluated near room temperature. The thermomechanical and aging treatments to optimize the mechanical properties of Cu-Al-Be wires for dampers through controlled grain growth are studied. In particular, the conditions to ensure the appropriate behavior without accumulative deformation against the cycle number, and in the coexistence zones, are analyzed. The pseudoelastic window of properly conditioned wires allows the use as dampers in civil engineering.
10.1016-j.msea.2006.02.089	4	transformation; martensite; martensitic; phase; shape; beta; memory; shape memory; temperature; temperatures; martensitic transformation; gamma; transformation temperatures; effect; thermal	In the last few years, a new Cu-Al-Ag shape memory alloy with high transformation temperature (M-s above 250 degrees C) has been developed. In order to investigate the influence of Ag content on the shape memory effect, four Cu-Al-Ag alloys with similar Al contents, but different Ag contents were selected. The microstructure and the transformation stability during thermal cycles of the four alloys have been studied by means of transmission electron microscopy (TEM) and differential scanning calorimetry (DSC). It was found that with the decrease of the silver content from 2.78 to 0.32 wt%, the microstructure of the martensite changed from dislocation tangles to parallel dislocation lines and to partial dislocations; and that with the decrease of the silver content, the stability of the phase transformations increased. The influence on shape memory effect is also discussed.
10.1016-j.msea.2006.02.099	4	transformation; martensite; martensitic; phase; shape; beta; memory; shape memory; temperature; temperatures; martensitic transformation; gamma; transformation temperatures; effect; thermal	The specific heat of Cu81.8Al13.7Ni4.5 (AK10) shape memory alloy has been studied by means of conventional DSC and adiabatic calorimetry techniques. The transformation temperatures and the shape of the calorimetric curves obtained by adiabatic calorimetry do not show any noticeable dependence on the temperature measurement rates, contrarily to what is observed by other calorimetric techniques. The dynamical character of the various experimental methods together with the influence of the latent heat associated to the first order character of these phase transitions are discussed. The specific heat of AK10 has been measured from 50 to 350 K which covers the phase transformation temperature range. The forward and reverse martensitic transformation peaks were found at 299.5 and 304.6 K, showing a thermal hysteresis of 5.1 degrees C. The C-p accuracy can be estimated in 0.1% of C-p and permits a reliable assignment of the following values to the phase transition thermodynamic functions: Delta H = 7.4 +/- 0.2 J/g and Delta S = 0.025 +/- 0.001 J/gK.
10.1016-j.msea.2006.02.123	4	transformation; martensite; martensitic; phase; shape; beta; memory; shape memory; temperature; temperatures; martensitic transformation; gamma; transformation temperatures; effect; thermal	It has been shown that both pinning- (mechanical) and reordering-induced (chemical) stabilization components contribute to the overall stabilization effect. An algorithm has been developed for quantitative analysis of the chemical and mechanical stabilization components, using routine calorimetry results. The basic idea underlying this algorithm is that chemical and mechanical stabilization components stem, respectively, from the factors, affecting thermodynamically reversible and irreversible factors during the first reverse transformation of the stabilized martensite. On a thermodynamical level, application of the suggested algorithm has been illustrated using experimental calorimetry results for a Cu-Zn-Al alloy. Here we report analysis of pinning and reordering processes on a microscopic scale, using experimental data on non-linear anelasticity in the same Cu-Zn-Al alloy to track different spatial and temporal localization of these processes during martensite ageing.
10.1016-j.msea.2006.02.139	4	transformation; martensite; martensitic; phase; shape; beta; memory; shape memory; temperature; temperatures; martensitic transformation; gamma; transformation temperatures; effect; thermal	Thermoelastic Cu-Al-Be is unusual in that during the first heating cycle after quenching the martensite is strongly stabilised and reverts to parent phase over two distinct temperature ranges. The higher temperature transformation range has been termed hyperstabilisation and the volume fraction of parent formed from hyperstabilised martensite has been found to depend sensitively on the quenching conditions. It has been suggested that the lower temperature (normal) stabilisation is due mainly to vacancy pinning, whereas hyperstabilisation arises from Be-induced suppression of beta phase ordering during rapid cooling. Both stabilisation effects are eliminated by thermal cycling to produce reverse transformation to beta phase, indicating that they arise from transient structural features of the initial quench . However, results presented herein indicate that no significant changes in the stabilisation phenomena occur following long-term room temperature ageing of the quenched martensite, indicating that the quenched-in defect structure is stable under ambient conditions. It was also found that hyperstabilisation can be accentuated by higher temperature/longer time heat treatments through loss of Be and a resultant increase in the martensitic transformation temperatures. The observations are consistent with the hypothesis that suppressed beta phase order plays a dominant role in hyperstabilisation.
10.1016-j.msea.2006.02.258	-1		In the present investigation, Cu47Ti33Ni6Sn2Si1 (numbers indicate at%) bulk metallic glass (BMG), fabricated by injection casting has been used for indentation experiments. Microindentation and nanoindentation tests were conducted to study the indentation responses of this material. The nanohardness and the Young's modulus were calculated following the standard procedure in literature. Around the indent, shear bands can be clearly observed under scanning electron microscopy examination. Atomic-force microscopy shows the pile of the material in a step-wise manner. The thinned sample near the indent shows the evolution of nanocrystals (similar to 20-30 nm) by transmission electron microscopy. During nanoindentation (in single- and multi-indent mode) experiments, the load-displacement P-h curves show displacement bursts, which are also known as pop-ins or serrations. The total displacement during indentation can be accounted for by sum total effect of the individual displacement of all the displacement-bursts observed in the P-h curve. Thus the plastic deformation of this glassy material appears to proceed in a discrete manner unlike ductile metallic alloys.
10.1016-j.msea.2006.02.306	-1		Experiments were conducted on bulk metallic glasses (BMGs) to identify a crucial factor that governs the degree of the plasticity shown by these alloys. It was found that in situ formation of nanocrystallites, which is known as the deformation-induced nanocrystallization, play a key role in providing initiation sites of the local deformation, indicating that a high degree of plasticity could be achieved from BMGs in which deformation facilitates nanocrystallization. The degree of this deformation-induced nanocrystallization was found to be strongly dependent on the activation energy for crystallization. In this paper, we report that a factor governing the plasticity of BMGs lies in the activation energy for crystallization.
10.1016-j.msea.2006.02.343	11	glass; bulk; metallic; bulk metallic; gfa; bmg; glassy; metallic glass; ability; bulk metallic glass; amorphous; addition; crystallization; mm; glass-forming	The supercooled liquid region A T of a Cu55Zr40Al5 (numbers indicate at%) glassy alloy increased by the addition of noble metals (Ag,Pd or Au) and the largest AT, reached 87 K for Cu50Zr40Al5Pd5. The reduced glass transition temperature (T-g/T-l, where T-g is the glass transition temperature and T, is the liquidus temperature) Of Cu50Zr40Al5M5 (M = Ag, Pd or An) glassy alloys is in the range from 0.60 to 0.61. The selection of the quaternary compositions enabled us to form bulk glassy alloys with diameters up to 3 mm. The Vickers hardness, Young's modulus, compressive fracture strength and plastic strain are 573-594, 106-118 GPa, 2050-2230 MPa and 0.004-0.015, respectively, for the Cu50Zr40Al5M5 (M = Ag, Pd, An) bulk glassy alloys. The addition of noble metals to the Cu55Zr40Al5 glassy alloy is effective for improving the corrosion resistance in IN H2SO4 solution. A different crystallization behavior was observed for Cu55Zr40Al5 and Cu50Zr4()Al5Pd5 glassy alloys.
10.1016-j.msea.2006.02.379	-1		Phase separation in undercooled Cu-25 wt% Cr melts was investigated using the electromagnetic levitation technique in combination with splat-quenching. The solidification microstructure of the levitated and splat-quenched samples showed many Cr-rich spheres in a Cu-rich matrix in addition to fine Cr-rich dendrites. The Cr-rich dendrites nucleated preferentially on the surface of the Cr-rich spheres, and grew outwards. Such a microstructure shows clear evidence of metastable liquid phase separation in undercooled Cu-Cr melts. In the levitated samples without splat-quenching, however, a dendritic microstructure was observed showing no evidence of liquid phase separation. The results are discussed in terms of a newly established phase diagram based on thermodynamic calculations.
10.1016-j.msea.2006.02.472	4	transformation; martensite; martensitic; phase; shape; beta; memory; shape memory; temperature; temperatures; martensitic transformation; gamma; transformation temperatures; effect; thermal	Elastic constants reflect the fundamental thermodynamic properties of the crystal lattice in solids. Essential information on the phase stability of transforming materials can be deduced from their temperature and stress dependencies. In this work, temperature dependence of all elastic constants of the cubic austenite and orthorhombic 2H martensite phases of the Cu-Al-Ni alloy in the transformation temperature range determined by resonance ultrasonic spectroscopy are reported. All measurements were performed on the same sample, existing first as a martensite single crystal (measurement during heating) and, after the reverse transformation took place, as the austenite single crystal (measurement during cooling). It was found that some elastic constants of the austenite phase (C ') and martensite phase (C-55, C-MS) significantly soften when approaching transformation temperatures. The martensite softening is by far more pronounced. While the austenite softening appears solely in the directions (110)(A) (C ' modes), the 2H martensite softens in the lattice corresponding directions [100](M) and [001](M) (C-55 modes) as well as along directions from a zone crossing the basal plane characterized by a elastic constant CMS newly introduced in our earlier related work. The elastic anisotropy of the both phases significantly increases when approaching transformation temperatures, the anisotropy factor of martensite increases about ten times more strongly than in the case of austenite.
10.1016-j.msea.2006.03.039	-1		In this study, the collapsing loads of cavitation bubbles generated by an ultrasonic vibratory device have been quantitatively evaluated for the as-casted and flame-quenched Cu-8.8Al-4.5Ni-4.5Fe (Al-bronze) alloys and their effects on the surface pitting after a short cavitation exposure have been numerically studied. The cavitation bubble collapsing loads were determined by measuring the cavitation pulse signal (V ut) and converting it into the impact load (F) by a ball drop test. A linear relation (F=A'V-out) between V-out and F was established with a different slope of A' for both materials. According to the impact load measurements, the flame-quenched Al-bronze underwent lower impact intensities compared to the as-cast one. For the flame-quenched At-bronze the critical impact load (L-c) required to form a pit more than 5 mu m (minimum observable size) was 12.9-13.5 N which is slightly lower compared to that of the as-casted M-bronze (13-13.8 N). The cavitation bubbles with the impact load value above L-c were very small, suggesting that the cavitation erosion leading a significant material loss is due to the surface fatigue by cumulative small impact loads.
10.1016-j.msea.2006.03.133	-1		Discs of Cu60Zr20Ti20 (at%) composition were produced by high pressure torsion. Radial dependence of the microstructure was monitored by X-ray diffraction and scanning electron microscopy. The inhomogeneous microstructure of the central region consists of particles of about 50 mu m and a surrounding matrix. With increasing radius, abrupt transitions take place in the morphology: first the large particles were attrited into lamellae then they transform into a homogeneous microstructure. Microindentation measurements revealed that the hardness showed a significant maximum with refining microstructure.
10.1016-j.msea.2006.03.145	-1		Cu-Ni-Zr-Ti bulk amorphous thin strips were produced by multi-pass warm rolling of the amorphous powder at temperatures in the supercooled liquid region. Process variables for rolling of the bulk amorphous strips were properly controlled to prevent onset of crystallization and failure during rolling up to three passes. During rolling of the amorphous powder, both the deformation and densification took place and the newly developed surface on the deformed amorphous particles enhances the consolidation leading to an increase in the strength . The strain state during rolling was analyzed by use of the finite element method. FEM results indicate that a high strain rate larger than 10 s(-1) prevails during rolling and gradients of the tensile strain rate in the rolling direction may initiate cracks.
10.1016-j.msea.2006.04.138	4	transformation; martensite; martensitic; phase; shape; beta; memory; shape memory; temperature; temperatures; martensitic transformation; gamma; transformation temperatures; effect; thermal	An extensive investigation of elastic and anelastic properties, at an ultrasonic frequency of around 100 kHz, of a variety of binary and ternary Cu-based alloys forming faulted martensites evidences the existence of a strong anelastic relaxation over a wide temperature range propagating down to lowest temperatures achieved in experiments of around 10 K. The anelastic phenomenon observed is the most pronounced for low oscillatory strain amplitudes (approximately from 10(-7) to 10(-6)) and results in a rapid decrease of Young's modulus (measured at low strain amplitudes) with increasing temperatures from the lowest values of around 10 K. The relaxation of Young's modulus is accompanied by a linear increase of the low-amplitude internal friction with increasing temperature. The low-temperature relaxational behaviour is strongly dependent on concentration of quenched-in vacancies: the relaxation is enhanced by P-phase ageing and is strongly suppressed by direct quenching of ternary Cu-Al-Ni, Cu-Zn-Al and Cu-Al-Be alloys. The anelastic effect observed exhibits an unusual property: the amplitude-independent internal friction background emerging as a result of this relaxation is non-additive with the amplitude-dependent internal friction. We suggest that this low-temperature relaxation is associated with a reversible transition from a cooperative to an individual mode of motion of the system of partial dislocations.
10.1016-j.msea.2006.04.146	-1		We have developed a new kind of metal matrix composites, based on powders of Cu-Al-Ni shape memory alloys (SMAs) surrounded by an indium matrix, specifically designed to exhibit high mechanical damping. The damping properties have been characterized by mechanical spectroscopy as a function of temperature between 150 and 400 K, frequency between 3 x 10(-3) and 3 Hz, and strain amplitude between 5 x 10(-6) and 10(-4). The material exhibits, in some range of temperature, internal friction as high as 0.54. The extremely high damping is discussed in the light of the microstructure of the material, which has been characterized in parallel.
10.1016-j.msea.2006.05.023	-1		The relative stability of the martensitic phases in Cu-Zn-Al shape memory alloys was used to evaluate the high-temperature equilibrium between the face-centered cubic and disordered hexagonal phases in a set of binary Hume-Rothery compounds. The equilibrium was found to be around an electron concentration of 1.44 in agreement with the available experimental binary phase diagrams. In the calculation, the contribution arising from the distortion of the martensitic structure due to long-range order was considered. It was additionally rationalized that, although the 18R phase is a common martensitic structure, it is not observed in the disordered state.
10.1016-j.msea.2006.05.081	-1		Isothermal annealing was applied to an equal-channel angularly pressed (ECAP) Cu-Fe-P alloy to investigate the stability of the fine-grained microstructure. The starting as-cast microstructure of the alloy contained two sets of second phase particles, fine gamma-Fe particles, and coarse Fe3P intermetallic particles. Following ECAP, while the fine Fe particles were well dispersed in the interior of the grains, many Fe3P particles were found outside the grains, along or at the junctions of grain boundaries. The presence of Fe3P particles at the grain boundaries enhanced the stability of the fine grain structure by delaying grain growth until 873 K when a coarse-grained structure developed. The different roles of the two sets of particles are discussed in terms of the difference in their deformation behavior.
10.1016-j.msea.2006.05.085	4	transformation; martensite; martensitic; phase; shape; beta; memory; shape memory; temperature; temperatures; martensitic transformation; gamma; transformation temperatures; effect; thermal	Polycrystalline Cu-11.5 wt% Al-0.5 wt% Be shape memory alloy specimens were subjected to both X-ray diffraction stress analysis and optical microscopy during stress-induced martensitic transformation at room temperature. During in situ uniaxial tensile test, the stress state of several grains with different orientations was correlated with martensitic variant development. Variant selection was verified with Schmid factor calculation, and a critical resolved shear stress of 70 MPa for martensitic transformation was identified. As the transformation developed, it was observed that the austenitic stress state in the grains depends mainly of martensitic volume fraction, number and arrangement of variants. The stress in the tensile direction decreases when the martensitic fraction increases.
10.1016-j.msea.2006.06.065	4	transformation; martensite; martensitic; phase; shape; beta; memory; shape memory; temperature; temperatures; martensitic transformation; gamma; transformation temperatures; effect; thermal	We have studied the mobility of defects in the frozen beta phase of the Cu-Al-Ni shape memory alloys by mechanical spectroscopy as a function of temperature. In parallel, we have characterized the microstructure and their evolution with over-heating treatments. Thermal treatments have been performed in situ in a transmission electron microscope by using a heating stage. Internal friction and modulus defect measurements have been correlated with the microstructural observations by transmission electron microscopy. We discuss the behavior of the internal friction spectra, corresponding to over-heating in the beta-phase, and propose microscopic mechanisms responsible for the evolution when the material is not in thermal equilibrium. In particular, the dislocations became mobile in the temperature range between 750 and 800 K where the L2(1) atomic order changes to the B2 order. A relaxation peak has been observed in the equilibrium beta phase domain, which has been examined in detail by isothermal measurements as a function of frequency. The activation enthalpy of the peak has been determined to be 3.05 +/- 0.1 eV, and possible microscopic mechanisms responsible for the peak are discussed.
10.1016-j.msea.2006.07.040	11	glass; bulk; metallic; bulk metallic; gfa; bmg; glassy; metallic glass; ability; bulk metallic glass; amorphous; addition; crystallization; mm; glass-forming	Graphite-flake reinforced Cu47Ti34Zr11 Ni-8 bulk metallic glass matrix composite was fabricated by water-cooled copper mould cast. Most of the graphite flakes still keep unreacted and distribute uniformly in the amorphous matrix except that some reactive wetting occurs by the formation of TiC particles around the flakes. It reveals that the presence of graphite flakes does not affect the onset of the glass transition temperature, crystallization reaction and liquidus of the metallic glass. The resulting material shows obvious serrated flow and higher fracture strength under room temperature compressive load, comparing with the monolithic bulk metallic glass (BMG). Three types of interaction between the shear bands and graphite flakes, namely, shear band termination, shear bands branching and new shear bands formation near the graphite flakes can be observed by quasi-static uniaxial compression test and bonded interface technique through Vickers indentation.
10.1016-j.msea.2006.08.055	4	transformation; martensite; martensitic; phase; shape; beta; memory; shape memory; temperature; temperatures; martensitic transformation; gamma; transformation temperatures; effect; thermal	The Ag precipitation and dissolution reactions in the Cu-3 wt% Al-4 wt% Ag alloy were studied using isothermal and non-isothermal analyses. The activation energy values, obtained for the Ag precipitation reaction indicated that, when the Kissinger, Ozawa and Johnson-MehI-Avrami methods are compared, the Kissinger method is the most appropriate. Although the Johnson-Mehl-Avrami equation often does not fit precipitation data, the energy values obtained for Ag precipitation kinetics are in agreement with what was experimentally observed. For the dissolution reaction of Ag precipitates the activation energy values obtained from the Kissinger and Ozawa methods are higher than that found in the literature for the Ag dissolution in Cu. This discrepancy seems to be related to the fact that the activation energy is influenced by the heating rate.
10.1016-j.msea.2006.08.069	4	transformation; martensite; martensitic; phase; shape; beta; memory; shape memory; temperature; temperatures; martensitic transformation; gamma; transformation temperatures; effect; thermal	The influence of ion irradiation on the formation of gamma phase precipitates and the degree of long-range order was studied in beta-Cu-Zn-Al-Ni alloys. Single crystals of beta-Cu-Zn-Al-Ni and beta-Cu-Zn-Al with surfaces close to (110)0 were irradiated simultaneously at normal incidence with 300 keV Cu ions at room temperature. The microstructural changes of both alloys, investigated with transmission electron microscopy (TEM), were compared. The formation of the gamma phase in quaternary Cu-Zn-Al-Ni, induced by room temperature irradiation, was observed for the first time. Irradiation was not able to completely destroy first neighbor and second neighbor ordering in the quaternary alloy. The observed behavior under irradiation was compared to that of thermal treatments. The presence of gamma phase precipitates in ion irradiated Cu-Zn-Al-Ni alloy is discussed.
10.1016-j.msea.2006.08.089	-1		Phase formation in the CU47Ti33Zr11Ni8Si1 alloy synthesized by various solidification techniques has been studied using X-ray diffraction (XRD). differential scanning calorimetry (DSC) and transmission electron microscopy (TEM) paying, in particular, attention to the TEM sample preparation. While a reduced cooling rate results in a duplex microstructure, consisting of nanocrystals in an amorphous matrix, glass formation is achieved upon employing a faster quenching rate. The difference in composition and quench temperature influence the phase transition upon heating. The essential differences observed in TEM, notwithstanding the ion-milling effects and the different pre-alloy ingots used for metallic glass synthesis, can be linked to differences in the nucleation and growth mechanism which, in turn, is influenced by the chemical short range order (CSRO) obtained upon quenching
10.1016-j.msea.2006.09.057	-1		This paper presents a detailed investigation into the influence of the rare earth (RE) oxide (La2O3) addition upon the densification and the resultant microstructural characteristics of the submicron WC-Co particulate reinforced Cu matrix composites prepared by direct laser sintering. It is found that the relative density of the laser sintered sample with 1 wt% La2O3 addition increased by 11.5% as compared with the sample without RE addition. The addition of RE element favored the microstructural refinement and improved the particulate dispersion homogeneity and the particulate/matrix interfacial coherence. The metallurgical functions of the RE element in improving the sinterability were also addressed. It shows that due to the unique properties of RE element such as high surface activity and large atomic radius, the addition of trace RE element can decrease the surface tension of the melt, resist the grain growth coarsening and increase the heterogeneous nucleation rate during laser sintering.
10.1016-j.msea.2006.09.177	11	glass; bulk; metallic; bulk metallic; gfa; bmg; glassy; metallic glass; ability; bulk metallic glass; amorphous; addition; crystallization; mm; glass-forming	The effects of yttrium addition on the glass forming ability and mechanical properties of (Cu(0.48)Zr(0.48)Al(0.04))(100-x)Y(x) (numbers indicate at%) alloys are investigated. It is found that the liquidus temperature does not change significantly with yttrium addition. The atomic level strain energy plays a role in destabilizing the competitive crystal phases. The atomic strain energy is closely related to the atomic packing efficiency of the precipitated crystalline phases. A small amount of yttrium addition increases the yield strength and slightly decreases the room temperature ductility. (C) 2007 Published by Elsevier B.V.
10.1016-j.msea.2006.10.053	4	transformation; martensite; martensitic; phase; shape; beta; memory; shape memory; temperature; temperatures; martensitic transformation; gamma; transformation temperatures; effect; thermal	Martensitic phase transition and martensite phase have an important effect on the physical and deformation properties of a material. In this paper, martensitic phase transition in elastic materials is modeled by using thermo-mechanical phenomenological theory. Based on the model proposed, stress-induced martensitic transition in Cu-Zn-Al shape memory alloy is studied by using finite element method. Stress-strain responses of Cu-Zn-Al single crystals under different applied stress rate are simulated by thermo-mechanically coupled calculation. Pseudoelastic deformation, hysteresis of transformation and hardening in stress-strain response are predicted in calculation results. Stress-strain curves determined from numerical simulation have a good agreement with those observed in experiments.
10.1016-j.msea.2006.10.112	0	solidification; phase; magnetic; magnetic field; undercooling; field; liquid; separation; peritectic; immiscible; cu-; dendrite; phase separation; microstructure; primary	Cu1-x-Cr-x (X=2-35 wt%) ribbons were prepared by melt spinning. The microstructure examinations revealed that depending on the compositions, the liquid phase separation occurred inevitably in Cu-Cr melts during melt spinning. The size of Cr particles from liquid phase separation increased with Cr content increasing when the ribbons contained less than 20 wt% Cr. However, the size increased a little when the Cr content increased from 25% to 35%. The Cu matrix of the as-quenched ribbons was supersaturated. It separated rapidly during annealing at 773-1173 K. All the coherent and incoherent precipitates were observed in the annealed ribbons. The size of precipitate particles was not dependent on the annealing time strongly. The liquid phase separation Cr particles played an important role in the separation of supersaturated solid solution. When the spaces between these particles were very small, the separated Cr atoms would diffuse to the interface between Cu matrix and Cr particles from liquid phase separation. Otherwise, fine Cr particles in nano-size precipitated in the Cu matrix.
10.1016-j.msea.2006.10.211	4	transformation; martensite; martensitic; phase; shape; beta; memory; shape memory; temperature; temperatures; martensitic transformation; gamma; transformation temperatures; effect; thermal	The behavior of helical springs made from lamellar specimens of Cu-Zn-Al shape memory alloy, which were martensitic at room temperature, was analyzed in force-elongation-temperature space. The study revealed the dependence of two forms of shape memory effect (SME): (i) work-generating SME and (ii) constrained-recovery SME, upon applied load and elongation, respectively. The tensile behavior of the springs, on loading between the austenite-start and the austenite-finish temperatures showed a stiffening tendency with increasing both elongation and temperature. The lamellar helical springs were able: (i) to lift 3 N loads over 0.235 m with a rate of 7 x 10(-3) m/K; (ii) to develop with a maximum rate of 0.6 N/m a recovery force as high as 24 N while being elongated by 0.232 m; (iii) to elongate by 7 x 10(-2) m under the effect of a 20 N force applied at 328 K, with an average rate of 342 N/m.
10.1016-j.msea.2006.11.051	-1		Electrical resistivity measurements have been performed for annealed Cu-Sn wires with compositions of 2, 5, 10 and 13.5 wt% Sn from room temperature to 700 degrees C. The annealing behaviour of cold-worked samples of these compositions has been investigated using resistometry, microhardness and optical microscopy. All samples undergo a hardness reduction of around 100 HV (300 g) on annealing. However, the room temperature resistivities differ greatly between the cold-worked and annealed condition only for the 10 and 13.5 wt% Sn samples, for which large resistance changes occur in the 300-500 degrees C range. Recrystallisation is delayed to around 400 degrees C in the high-tin samples; interaction between annealing and Cu3Sn (epsilon phase) precipitation is proposed as an explanation for the resistivity behaviour of these samples. The implications of these resistivity results for resistometric monitoring and optimisation of bronze route Nb3Sn superconducting wires are summarised.
10.1016-j.msea.2006.11.069	4	transformation; martensite; martensitic; phase; shape; beta; memory; shape memory; temperature; temperatures; martensitic transformation; gamma; transformation temperatures; effect; thermal	The mechanical response of beta (parent)-phase aged Cu-Al-Ni single crystal shape memory alloys (SMAs) was investigated at temperatures above and below the transition regime. Two alloys, one in austenitic (alloy A) and the other in martensitic (alloy M) condition in the as-grown state at room temperature, were examined. Both the tensile and the compression responses and their variation with aging were evaluated. With aging, successive martensitic transitions (beta(1)' -> gamma(1)') in both the alloys and precipitate formation ( gamma(2)) in the alloy A occur. Compression loading of the aged samples shows large mechanical hysteresis and stabilization of gamma(1)', martensite which results in permanent strain after unloading. In addition, a noticeable increase in critical stress for transformation in the aged samples vis-alpha-vis the as-quenched sample is seen. In tension, low temperature aged (473 K) samples show an increase in the critical stress for transformation in alloy M. Differences in the stress-strain hysteresis characteristics of alloys tested at various temperatures indicate the presence of different kinds of martensites (beta(1)' and gamma(1)') in the two alloys.
10.1016-j.msea.2006.11.092	4	transformation; martensite; martensitic; phase; shape; beta; memory; shape memory; temperature; temperatures; martensitic transformation; gamma; transformation temperatures; effect; thermal	The formation of the alpha fee phase during the dezincification of beta Cu-Zn was in situ observed. The transformation temperature (470 degrees C) was close to the minimum temperature at which the transformation could be detected in previous works. The reason for choosing this temperature was that in this way the transformation proceeds sufficiently slowly, making it possible to observe clearly the nucleation stage and the growing process at the surface of the sample. The progress of the dezincification experiment was recorded as a function of time allowing to follow the growing process of fee needles. The experiments indicated that the formation ofthe fcc precipitates takes place by a heterogeneous mechanism.
10.1016-j.msea.2006.12.101	2	corrosion; surface; film; electrochemical; films; spectroscopy; layer; current; solution; potential; resistance; composition; x-ray; ions; showed	Copper films were electrodeposited under various conditions and the relationship between the hardness and grain size of the films was investigated. The Vickers hardness depended on the processing conditions. This is because the processing conditions affected the grain size. In particular, nanocrystalline Cu film with a grain size of 31 nm was obtained by optimizing the electrodeposition conditions. The hardness of the nanocrystalline film deviated from the Hall-Petch relationship because the grain size dependence of hardness is smaller for the grain sizes of < 100 nm than those of > 100 nm. Also, the constants HV(0) and k(HV) in the Hall-Petch relationship for films processed with thiourea were different from those for films processed with gelatin. The differences may not be related to texture but to superabundant vacancies generated in the process of electrodeposition.
10.1016-j.msea.2006.12.133	-1		The performance of several overlay coatings on Cu-8 at. %Cr4%Nb alloy (GRCop-84) thermally cycled in a high heat flux hydrogen-oxygen combustion flame are reported. Finite element analyses (FEA) were conducted to evaluate the expected performances of coatings with different thermal conductivities as well as to determine a suitable thickness for coating deposition. Top coats consisting of Cu-26%Cr, NiAl and NiCrAlY along with a Cu-8%Cr bond coat were vacuum plasma sprayed on GRCop-84 thin sheet specimens. It was observed that the Cu-26%Cr coating formed blisters whereas the NiAl and NiCrAlY coatings showed no significant differences between the exposed and unexposed specimens. Water-cooled rectangular specimens specially designed to simulate a rocket engine liner were coated with a NiCrAlY-top coat using either a Cu-8%Cr or a Cu-8%Cr-1%Al bond coat. Preliminary tests conducted on these specimens showed no visible evidence of coating spallation after 40 cycles. The measured temperatures and heat fluxes were used in FEA models to estimate the stresses, strains and temperatures across the coating interfaces in these specimens. Published by Elsevier B.V.
10.1016-j.msea.2006.12.200	-1		Rapidly quenched Cu-Al-based thin wires of approximately 100 mu m, in diameter produced by in-rotating-liquid-spinning process (INROLISP) exhibit shape memory behaviour. In contrast to the production mode used for preparing thin Cu-Al wires showing the shape memory effect described in recent publications, a horizontal arrangement of the INROLISP process was used for the fabrication on a laboratory scale. The effects of the process parameters on the quality of the thin wires have been studied. Scanning electron microscopy was performed to investigate the influence of rapid solidification on the grain size. In order to characterize the shape memory behaviour, the characteristic transformation temperatures were determined by differential scanning calorimetry and tensile tests. In performing these measurements, the INROLISP process parameters like melt jet velocity (Reynolds' number), flow velocity of the coolant, melt superheating and alloy compositions were taken into account.
10.1016-j.msea.2006.12.223	4	transformation; martensite; martensitic; phase; shape; beta; memory; shape memory; temperature; temperatures; martensitic transformation; gamma; transformation temperatures; effect; thermal	The paper reports some austenitization effects on the alpha-phase morphology in a tempered martensitic Cu-21.57 Zn-7 Al (wt%) shape memory alloy (SMA). By means of differential scanning calorimetry, X-ray diffraction and optical and electron microscopy, it has been shown that the effects of the stress-state induced in austenite persist even after martensitic transformation and tempering at 773 K. The two analyzed austenitization states, hot-pressed and homogenized, respectively, aimed to reproduce two steps of an industrial technologic flow for SMA manufacturing. Basically, austenitic hot-working diminished the size of disoriented alpha-phase precipitates while austenitic homogenization enabled the formation of a Widmanstatten structure with oriented long alpha-phase needles, among which those corresponding to alpha(1 11) intersect at about 70 degrees and those corresponding to alpha(2 0 0) at 90 degrees.
10.1016-j.msea.2006.12.224	4	transformation; martensite; martensitic; phase; shape; beta; memory; shape memory; temperature; temperatures; martensitic transformation; gamma; transformation temperatures; effect; thermal	Elastic constants of austenite and martensite phases in shape memory alloys reflect fundamental thermodynamic properties of these materials-i.e. important physical information can be deduced not just from the values of the constants but, mainly from their temperature and stress dependencies. As regards to the parent austenite phase, such information is available in the literature for most of the known shape memory alloys. For the martensitic phases, however, only few reliable experimental data exist, due to the experimental difficulties with the preparation of martensite single crystals as well as due to the difficulties with the ultrasonic measurement of elastic properties of strongly anisotropic media with low symmetry. In this work, the temperature dependence of all elastic constants of cubic austenite and orthorhombic 2H martensite phases in Cu-Al-Ni alloy determined by resonance ultrasound spectroscopy (RUS) is reported. Experimental and theoretical improvements of the RUS method which had to be made to perform the successful measurements on strongly anisotropic and martensitic phases are discussed. (c) 2007 Published by Elsevier B.V.
10.1016-j.msea.2006.12.232	4	transformation; martensite; martensitic; phase; shape; beta; memory; shape memory; temperature; temperatures; martensitic transformation; gamma; transformation temperatures; effect; thermal	Strips of Cu-13Al-5Ni-1Ti (wt%) of about 400 mu m thickness were obtained by twin-roll casting directly from the melt. Temperature-induced transformations under constant tensile load show a larger deformation, associated with the reversible martensitic transformation, for strips annealed at 700 degrees C and 900 degrees C than for the as-cast samples. This effect is partially ascribed to relaxation of internal stresses produced by the rapid solidification, some recovery of short-range disorder and microstructural changes related to Ti-rich X-phase precipitates. On the other hand, the strips show a columnar grain morphology and annealing leads to an increase of texture intensity related with the increase in elongation rate. Columnar grains are mostly aligned with the < 0 4 0 > (R18) // < 100 > (DO3) directions.
10.1016-j.msea.2006.12.238	4	transformation; martensite; martensitic; phase; shape; beta; memory; shape memory; temperature; temperatures; martensitic transformation; gamma; transformation temperatures; effect; thermal	We investigate nanoparticles of the ferromagnetic Cu2MnAl phase which precipitate from a supersaturated paramagnetic Cu-Al-Mn solid solution. Changes of the magnetic properties of those particles during the martensitic transformation are caused by the internal stresses which arise due to the misfit between the lattices of the particles and the martensite. An increase of the magnetic anisotropy constant of the particles has been revealed. This increase can be attributed to the increase of the coherency stresses. The intensity of the coherency stresses has been evaluated on the basis of magnetic measurements.
10.1016-j.msea.2007.01.023	-1		Cu-1.2 wt%Cr and Cu-3.2 wt%Cr alloys were prepared by spray forming. The as-deposited alloys were subsequently warm rolled at 300 degrees C with a 40% reduction and then two types of thermo-mechanical treatments were adopted to enhance the mechanical properties of the Cu-Cr alloys. The microstructural features of the Cu-Cr alloys in different thermo-mechanical processing conditions were characterized using optical, scanning electron and transmission electron microscopy techniques. The results show that the spray-formed Cu-Cr alloys exhibit a better response to heat treatment compared to the conventional casting alloys. The chromium content has a great effect on the aging behaviors of the Cu-Cr alloys. Although a higher chromium content leads to a larger volume fraction of chromium precipitates generated during the solidification, it does not cause an increase in the mechanical properties. The chromium content should be lower than 1.2 wt%.
10.1016-j.msea.2007.01.172	4	transformation; martensite; martensitic; phase; shape; beta; memory; shape memory; temperature; temperatures; martensitic transformation; gamma; transformation temperatures; effect; thermal	We report specific heat measurements from 2 to 300 K in two Cu-Zn-Al shape-memory alloys. One remains in the parent phase, while the other is in the martensitic phase over the full measurement range. Data confirm the existence of a boson peak in the parent L2(1)-phase of the studied material. A model is proposed that assumes that the boson peak is associated with the excess of vibrational entropy of the L2(1)-phase with respect to the martensitic phase. The computed excess of entropy is in agreement with data obtained from calorimetric measurements in Cu-Zn-Al samples of selected compositions that transform martensitically in the temperature range from 30 to 250 K.
10.1016-j.msea.2007.01.173	4	transformation; martensite; martensitic; phase; shape; beta; memory; shape memory; temperature; temperatures; martensitic transformation; gamma; transformation temperatures; effect; thermal	An acoustic technique operating at a frequency of about 100 kHz and strain amplitudes of 10(-7) to 2 x 10(-4) is employed to investigate diffusion mobility of point-like defects in the beta(1)' martensitic phase of a Cu-10.4 wt% Al-0.47 wt% Be single crystal at temperatures down to 9 K. Diffusion of the quenched-in point-like defects in the Cu-Al-Be martensite is detected by amplitude-dependent anelasticity at much lower temperatures than for other Cu-based martensitic alloys (Cu-Al, Cu-Al-Ni, Cu-Zn-Al). Strain amplitude dependence of the internal friction and Young's modulus defect indicates that the formation of pinning atmospheres at temperatures up to 200 K is restricted to the regions swept up by oscillating partial dislocations/interfaces and, therefore, should be attributed to the efficient dislocation/interface-assisted diffusion of point-like defects. Observation of the intense defect-assisted diffusion in the Cu-Al-Be martensite accounts for the extremely strong kinetic stabilisation of martensite in Cu-Al-Be, which is evident from calorimetry data and is much less intense in other Cu-based martensites.
10.1016-j.msea.2007.01.174	4	transformation; martensite; martensitic; phase; shape; beta; memory; shape memory; temperature; temperatures; martensitic transformation; gamma; transformation temperatures; effect; thermal	The structure of a Cu-13.67AI-4.28Ni-0.54Mn-0.14Fe (wt%) shape memory alloy was analyzed in the initial condition, during a heating-cooling cycle, and during a room temperature loading-unloading mechanical cycle. A fully reversible martensitic transformation was revealed which was associated with a shape recovery degree reaching a saturation value at 97.7% for a relative permanent deflection of 90 %. By X-ray diffraction, the occurrence of a reduced amount of beta(1)', stress-induced martensite (SIM) accompanied by the precipitation of the hard gamma(2)-phase was noticed both during the heating of a martensitic specimen and during the air-cooling of the alloy in the austenitic state. It was assumed that a possible cause for the formation of beta(1)', SIM during heating or cooling could be the strains caused by the volume increase of hard gamma(2)-phase that deformed the softer martensitic or the austenitic matrix. The irreversible formation of beta(1)' SIM at 100 MPa was revealed by X-ray diffraction in elongated condition and confirmed by OM at room temperature, after unloading.
10.1016-j.msea.2007.01.186	4	transformation; martensite; martensitic; phase; shape; beta; memory; shape memory; temperature; temperatures; martensitic transformation; gamma; transformation temperatures; effect; thermal	New metal matrix composites were developed with a view to elaborating high-damping materials. These composites were produced by infiltrating a relatively high amount of Cu-Al-Ni shape memory alloy particles with soft metallic matrices. Details on the processing method as well as on the composite microstructure are given in the present paper. An inverted torsion pendulum was used to determine the damping capacity tan S. High damping values were measured, what implies a promising future for these composites as high-damping materials. The influence of thermal treatments on the microstructure and on the thermoelastic martensitic transformation is discussed. The damping capacity of these materials is associated with the mobility of the martensite interfaces, and a synergetic interaction between the particles and the matrices is suggested.
10.1016-j.msea.2007.01.189	4	transformation; martensite; martensitic; phase; shape; beta; memory; shape memory; temperature; temperatures; martensitic transformation; gamma; transformation temperatures; effect; thermal	A neutron single crystal diffraction method for inspecting the quality of martensite single crystals is introduced. True interface-free martensite single crystals are indispensable for, e.g. measurement of elastic constants of phases by ultrasonic techniques. The neutron diffraction method was used to detect and distinguish the presence of individual lattice correspondence variants of the 2H orthorhombic martensite phase in Cu-Al-Ni as well as to follow the activity of twinning processes during the deformation test on the martensite variant single crystals. When preparing the martensite single variant prism-shaped crystals by compression deformation method, typically a small fraction of second unwanted martensitic variant (compound twin) remains in the prism samples. Due to the very low stress (similar to 1 MPa) for the compound twinning in many shape memory alloys, it is quite difficult not only to deplete the martensite prisms of all internal interfaces but mainly to keep them in the martensite single variant state for a long time needed for further investigations.
10.1016-j.msea.2007.02.039	-1		This paper presents an influence of Ag addition on the glass-forming ability and devitrification behavior of Cu-Zr glassy alloys on heating. The crystallization kinetics and structure changes in Cu45Zr45Ag10 and Cu35Zr45Ag20 glassy alloys on heating were studied by X-ray diffraction, transmission electron microscopy, differential scanning and isothermal calorimetry methods. Based on the results obtained one can assume that the improvement of the glass-forming ability of the Cu-Zr alloys by the addition of Ag is connected with a particular crystallization mechanism and a higher reduced glass-transition temperature of the Cu45Zr45Ag10 ternary alloy compared to the binary Cu55Zr45 counterpart. As observed in the present work crystallization of the Cu-Zr-Ag alloys is found to cause embitterment of the samples and should be avoided as these alloys are considered to be used as structural materials. The Cu35Zr45Ag20 alloy shows possible submicron-scale phase separation upon annealing.
10.1016-j.msea.2007.02.164	4	transformation; martensite; martensitic; phase; shape; beta; memory; shape memory; temperature; temperatures; martensitic transformation; gamma; transformation temperatures; effect; thermal	The effect of thermal cycling in the martensitic phase transitions of a Cu-Zn-Al single crystal shape-memory alloy has been studied by monitoring the acoustic activity generated during the transition. The correlation function between the acoustic activity of k and k + Delta k cycles has been computed for the whole transformation and for selected temperature intervals Delta T within the transition region. Results indicate that for the whole transition there is a learning process in which the system seeks an optimal path of its internal variables that connect the parent and the martensitic phases. The learning process in the central part of the transition dominates the global behaviour and is different from the behaviour in the early- and late-stages of the transition.
10.1016-j.msea.2007.04.056	-1		Electrical conductivity, tensile strength and micro-hardness of Cu-0.43 wt% Cr-0.17 wt% Zr-0.05 wt% Mg-0.1 wt% RE alloy were investigated after cold working and aging treatment. The results show that good combination of the physical and mechanical properties can be obtained after aging at 450 degrees C for 4 h . The analysis of the microstructure by high resolution transmission electron microscopy (HRTEM) show that three kinds of strengthening phases, such as chromium-rich phase, zirconium-rich phase and the CrCu2(Zr, Mg) particles were observed. Most of the chromium-rich phase and zirconium-rich phase dispersed separately, and few of them congregated together in the matrix. The CrCu2(Zr, Mg) phase may be decomposed into chromium-rich phase and zirconium-rich phase at aging temperature above 450 degrees C. (c) 2007 Published by Elsevier B.V.
10.1016-j.msea.2007.04.074	6	grain; deformation; strain; strength; dislocation; cu-; tensile; size; ecap; grain size; sfe; ductility; hardening; high; stress	The S-N and Coffin-Manson plot, cyclic stress-strain response, changes of microstructure, and the surface morphology of ultra-fine grain (UFG) low-purity copper processed by ECAP were tested and observed in present study. And the formation mechanism of shear bands was discussed in detail. The results show that the UFG Cu represents longer lifetime under stress-controlled fatigue, but lower fatigue resistance under strain-controlled fatigue when compared with the coarse grain counterpart. Cyclic stress-strain responses of UFG Cu under stress-controlled fatigue alter from cyclic softening to cyclic hardening as stress amplitude decreases. But the responses always show cyclic softening under strain-controlled fatigue in present testing. By electron back scattering diffraction and transmission electron microscope technique, the shear bands were discovered on the surface of all cycled samples and no grain coarsening was discovered near the shear bands, which indicated that there was no inevitable relationship between formation of SBs and cyclic softening/grain coarsening. The discovery should be related to impurities in copper. The oriented distribution of defects along the shear plane in the last ECAP processing is one of the major mechanisms of SBs formation.
10.1016-j.msea.2007.05.013	-1		The mechanical properties of a Cu-2.16Ni-0.72Si alloy in a hardened state are investigated at room temperature (RT) and up to 573 K through tensile tests performed at slow and fast straining rates. In the upper temperature range the material ductility exhibits an anomalous behaviour typical of dynamic embrittlement: the ductility decreases with increasing temperature or/and with decreasing straining rate. SEM observations confirm that result: the fracture surfaces of the broken specimens are predominantly of ductile type at RT, while they are covered of many intergranular facets for specimens tested in the upper temperature range at slow straining rate. The role of stress is predominant in the mechanism of embrittlement. A model of dynamic embrittlement controlled by diffusion is used to derive a factor of embrittlement, S-DE, related to the testing conditions. This factor appears to be well correlated with the variation of the ductility linked with the testing conditions.
10.1016-j.msea.2007.05.083	6	grain; deformation; strain; strength; dislocation; cu-; tensile; size; ecap; grain size; sfe; ductility; hardening; high; stress	Pure Cu of 99.98 wt% purity has been processed at room temperature by diverse techniques of severe plastic deformation, namely equal-channel angular pressing (ECAP), high pressure torsion (HPT) and a combination of both in order to find out the evolution on the microstructural homogeneity for each of the processes and their combination. Starting with a grain size of similar to 60 mu m, severe plastic deformation has been introduced to the material while maintaining the sample dimensions unchanged through the processes of ECAP and HPT. A significant decrease in grain size was observed by transmission electronic microscopy (TEM). Microtensile and microhardness tests were carried out on the deformed material in the three processing conditions. A significant improvement of the tensile strength was promoted with admissible penalization on ductility.
10.1016-j.msea.2007.06.018	-1		In this paper, 5 rum diameter Cu46.5Zr48.5Al5 bulk metallic glass forming alloys were prepared by water cooled Cu-mould cast. Microstructural observation shows that the alloys consist of amorphous phase and crystalline phase containing CuZr martensite. The deformation behaviors of the crystalline region and amorphous phase in the alloys were studied by means of nanoindentation tests under progressive multicycle mode. The results reveal that the unloading and the subsequent reloading h-p curves for the amorphous phase can retrace each other. While for the crystalline region, an obvious hysteresis loop was found between the unloading and reloading h-p curves in the typically elastic regime, indicating the occurrence of 'stress-induced phase transformation'. This unique deformation behavior of the material was also confirmed by using uniaxial compression tests.
10.1016-j.msea.2007.06.034	16	wear; composite; composites; powders; milling; particles; powder; wt; sliding; friction; hardness; matrix; mechanical; surface; properties	Friction and wear behavior of copper matrix composites reinforced by unidirectional Nb fibers were explored using both pin-on-ring and pin on disk set-ups. Composite specimens were manufactured from a Cu-18 vol.% Nb powder mixture. Through various mechanical processes and heat treatments, this powder mixture was converted to a 'ribbon-shaped Nb' fiber reinforced copper composite with final average fiber thickness of about 10 nm and aspect ratio of about 30. The friction and wear properties of this composite were evaluated against gray cast iron with the hardness of 92 HRB. The effects of normal load, sliding speed and fiber orientation on the friction and wear of this composite were investigated. Steady state wear was observed upon formation of a thin film on the wear surface for all the specimens. This film formed due to the material transfer from the disk to the composite surface due to low ductility of the copper matrix. The wear rate was proportional to the sliding distance and normal load for all specimens, while specimens with fibers normal to the sliding surface showed the lowest wear rate. Moreover, the wear rate appeared to be an exponential function of the sliding speed. This was related to temperature rise at the interface of sliding surfaces and recovery of Cu matrix and possible breakage of the Nb fibers. Metalographic examination of Cu-Nb micro-fiber reinforced composite showed that when exposed to temperature greater than 600 degrees C, fibers start to break and spherodized. This phenomenon significantly reduces the strength of Cu-Nb composite and increases its wear rate. Some insight into the mechanisms of wear was obtained using optical and scanning electron microscopy and energy dispersive spectrometry analysis of the surface.
10.1016-j.msea.2007.07.051	-1		Cu-12 wt% Ag filamentary composite was prepared by drawing and annealing. The intensity and distribution of crystal texture were determined. The preferred crystal orientation in Ag phase forms more rapidly during drawing strain than in Cu phase. Drawing deformation produces three texture components (1 0 0), (1 1 1) and (2 1 1) in Cu phase and single texture component (1 1 1) in Ag phase. In a certain strain range, the intensities of all texture components increase with drawing deformation. The (1 0 0) intensity in Cu phase keeps basically constant and the (1 1 1) intensity in Cu and Ag phases decreases as the strain exceeds a certain level. Annealing treatment modifies the intensities of deformation texture due to interface migrating, fiber breaking, grain propagating and structure spheroidizing. Annealing at lower temperatures enhances the (1 0 0) intensity and reduces the (1 1 1) intensity in Cu phase. Annealing at higher temperatures enhances the (1 1 1) intensity in Cu and Ag phases.
10.1016-j.msea.2007.08.100	-1		Metal matrix composites for high-damping application were produced by embedding soft metallic matrices (pure In, In-10 wt% Sri and In + Sri eutectic alloys) in powders of Cu-Al-Ni shape memory alloys (SMAs). During the composite production, the shape memory alloy particles interact with the molten matrices giving place to Cu dissolution from the shape memory alloy particles to the matrices, grain boundary penetration, and formation of intermetallic compounds. Adhesion, wetting and interfacial reaction are crucial for the final composites properties. Preliminary results on microstructural investigations performed applying optical and electron microscopy are presented in this contribution. The influence of thermal treatments on the microstructure of one composite is also discussed.
10.1016-j.msea.2007.11.015	-1		Considerable intergranular embrittlement of Cu takes place due to segregation of Bi on grain boundaries. However, the concentration of Bi for the grain boundary segregation varies depending on the character of the grain boundary. In order to examine the relationship between the embrittlement and the character of the grain boundary, the dependence of the behavior of fracture on the inclination angle was experimentally observed at temperatures of T = 298 and 77 K for the Sigma 9 [110] asymmetric tilt boundary in Cu doped with Bi. For the high-energy boundary, the brittle fracture occurs in an intergranular manner at both temperatures. On the other hand, for the low-energy boundary, the ductile fracture takes place in a transgranular manner at T = 298 K but in a transgranular or intergranular manner at T = 77 K. The concentration of Bi for the grain boundary segregation may be large in the high-energy boundary but small in the low-energy boundary. According to estimation, the thermodynamic interaction between Cu and Bi in the grain boundary is repulsive, Furthermore, the repulsive interaction is more notable for the high-energy boundary than for the low-energy boundary. Consequently. the fracture occurs brittlely for the high-energy boundary with a large Bi concentration but ductilely for the low-energy boundary with a small Bi concentration.
10.1016-j.msea.2007.11.037	16	wear; composite; composites; powders; milling; particles; powder; wt; sliding; friction; hardness; matrix; mechanical; surface; properties	The fabrication conditions of Cu-Al-Ni-Mn alloy powder by mechanical alloying and powder metallurgy have been systematically studied. The mechanically alloyed powder (MAed powder) was fabricated at a speed between 100 rpm and 300 rpm for various milling times with and without process control agent (PCA). With an increasing of milling time, the size of crystallite grain decreases. Only the Cu diffraction pattern appear as the rotation speed is up to 300 rpm for 25 h . The elemental powders with PCA agglomerate slightly, but the degree of alloying is lower than that without PCA. The shape memory recovery of the quenched sample hot-extruded at extrusion rate of 50:1 is measured to be 100% recovered in 250 degrees C oil bath for 40 s after deformed to 4.0%. After aging at 120 degrees C for 10 days, the shape memory recovery of the alloy remains 98%.
10.1016-j.msea.2008.04.119	6	grain; deformation; strain; strength; dislocation; cu-; tensile; size; ecap; grain size; sfe; ductility; hardening; high; stress	Cyclic creep and fracture behavior at 673 K of orientation-controlled Cu-SiO2 bicrystals with [0 0 1] twist 20 degrees grain boundaries was investigated. The cyclic creep and life depended on both the stress amplitude and the frequency of the cyclic load. Most bicrystals fractured intergranularly. The number of cycles to failure shortened drastically with decreasing the frequency and with increasing the stress amplitude, while the time to failure remained nearly the same irrespective of the frequency. Since the cyclic creep life was controlled by the occurrence of grain-boundary fracture, the above observations can be understood reasonably by considering stress concentration and void formation at grain-boundary SiO2 particles. When grain-boundary sliding takes place, the particles impede the sliding and the stress concentration sites are created. This causes the intergranular fracture and controls the cyclic creep life.
10.1016-j.msea.2008.06.004	4	transformation; martensite; martensitic; phase; shape; beta; memory; shape memory; temperature; temperatures; martensitic transformation; gamma; transformation temperatures; effect; thermal	The Portevin-LeChatelier (PLC) effect exemplifies itself as continuous stress changes during the tensile deformation of particular alloys. The PLC effect takes several forms, which differ significantly in both the spatial distribution of strain bands and in the shape of the stress-strain curve. The courses corresponding to particular serration types are characterized by different properties of the signal energy distribution, depending on the conditions under which the tensile process is carried out, as well as on the parameters connected with metallurgical processing of the material. It was also found that the energy distribution depends on the instantaneous value of strain/stress, which justifies the application of time-frequency analysis methods to obtain the detailed spectral characteristics of the Portevin-LeChatelier effect.
10.1016-j.msea.2008.06.042	-1		Ultra-fine grain (UFG) Cu-0.69 wt% Cr alloy with the average grain size ranging from 320 nm to 550 nm was prepared by equal-channel angular pressing (ECAP) with 4-6 passes. The high-cycle fatigue behaviors were studied experimently by loading in stress-control at a frequency of 30 Hz. The relevant coefficients on the energetic approach for fatigue crack initiation (FCI) life assessment were also tested and estimated with the conventional mechanical data for UFG Cu-0.69 wt% Cr alloy. Two different models, the energetic approach and the Basquin's expression, were selected to compare and found that the fitted values of parameters based on the energetic approach are much closer to the experimental points than those of Basquin's expression. Based on the energetic approach, excellent agreement was obtained between the theoretical prediction of the fatigue crack initiation life and the experiments for the UFG materials. The fatigue limit, A(7, and the equivalent endurance limit (Delta sigma(eqv))(th), increase with increasing number of ECAP passes.
10.1016-j.msea.2008.08.014	-1		The filamentary composites of Cu-6 wt% Ag and Cu-12 wt% Ag containing rare-earth elements with different contents were prepared by casting and cold drawing. The microstructure was observed and the tensile strength determined for the composites at different draw ratios. The rare-earth elements of 0.05-0.15 wt% in Cu-6 wt% Ag and 0.1-0.3 wt% in Cu-12 wt% Ag result in large spacing or low density of the filamentary interface in the composites. Some hard compound particles exist in the composites containing rare-earth elements and result in high stress concentration. The rare-earth additions in the composites can improve the strength at low drawing degrees but reduce the strength at high drawing degrees.
10.1016-j.msea.2008.08.029	6	grain; deformation; strain; strength; dislocation; cu-; tensile; size; ecap; grain size; sfe; ductility; hardening; high; stress	The high temperature tensile properties of solution treated, cold worked and peak aged Cu-1.5 wt%Ti and Cu-4.5 wt%Ti alloys have been investigated in the temperature range from room temperature (RT) to 550 degrees C. Yield strength (YS) and tensile strength (TS) of Cu-1.5Ti alloy were found to be independent of test temperature up to 350 degrees C and decreased thereafter, up to 550 degrees C. In the case of Cu-4.5Ti alloy, behaviour similar to Cu-1.5Ti alloy was observed. The decrease in strengths beyond 350 degrees C is attributed to coarsening of beta' precipitate particles at 450 degrees C and precipitation of equilibrium phase P at 550 degrees C. TEM analysis of the alloys confirms the presence of metastable and coherent Cu(4)Ti beta' precipitate when tested at 450 degrees C and equilibrium precipitate Cu(3)Ti, beta' at the test temperature of 550 degrees C. It is interesting to note that in the cold worked and peak aged Cu-Ti alloys tested at elevated temperatures, ductility (% elongation) was found to increase with the test temperature up to 550 degrees C which is attributed to dynamic recrystallisation. The large elongation (160%) observed in Cu-4.5Ti alloy at the test temperature of 550 degrees C is an indication of superplasticity. We are reporting the discovery of superplasticity in Cu-4.5Ti alloy for the first time. Ductile mode of fracture was observed in these alloys tested at elevated temperatures, i.e. at 350 and 450 degrees C. High temperature tensile Properties of Cu-Ti alloys are found to be superior to those of Cu-Be alloys (C17200 and C17510).
10.1016-j.msea.2008.09.096	4	transformation; martensite; martensitic; phase; shape; beta; memory; shape memory; temperature; temperatures; martensitic transformation; gamma; transformation temperatures; effect; thermal	A Cu-Al single crystal with 7 at% All has been studied using isothermal mechanical spectroscopy (IMS) technique. After a 1% cold work by torsion, the samples have been progressively heated to 1140 K and then cooled down to room temperature. IMS experiments allow to compare the isothermal internal friction spectra obtained during heating (in this case, the annealing temperature is equal to the temperature of measurement) with the measurements performed at various temperatures during cooling after annealing at 1140 K. This paper is focused on two relaxation peaks observed in the temperature range 750-1140 K. The first one, called here P1 (at about 0.6 T-M at 1 Hz), decreased with increasing the annealing temperature, while a new relaxation peak P2 (at about 0.8 T-M at 1 Hz) progressively developed. Because the internal friction spectra are complex (one or two peaks superimposed to background), a particular technique for background subtraction was used. The evolution of the peaks with temperature was monitored and their relaxation parameters accurately determined. P1 and P2 peaks have been assigned to the motion of dislocation segments inside the sample microstructure.
10.1016-j.msea.2008.09.121	3	sma; shape; shape memory; memory; smas; superelastic; bars; damping; cu-al-mn; mechanical; bending; applications; numerical; sma bars; material	High-damping materials have attracted much attention to solve problems such as acoustic pollution, nano-scale vibration isolations in electronic industry, vibration damping in civil engineering, etc. Shape memory alloys (SMAs), which intrinsically present high-damping capacity, are considered as alternative materials to the traditionally used polymeric ones, because they present better mechanical properties at moderate temperatures. A new kind of high-damping metal matrix composites has been produced by embedding a relatively high amount (approximately 60 vol.%) of Cu-Al-Ni SMA particles with metallic matrices (In, In + Sn). The damping properties have been characterized by mechanical spectroscopy, using an inverted torsion pendulum, as a function of temperature (150-400 K), frequency (0.01-3 Hz), and strain amplitude (2 x 10(-5) to 8 x 10(-5)). The materials exhibit internal friction higher than 0.5 in a relatively wide temperature range. The ability of matching the temperature of maximum damping, through the composition of the SMA, opens new possibilities for designing high-damping materials for specific applications.
10.1016-j.msea.2008.10.002	16	wear; composite; composites; powders; milling; particles; powder; wt; sliding; friction; hardness; matrix; mechanical; surface; properties	The present investigation discusses observations pertaining to the synthesis of Cu-based composites containing TiC particles in the range of 45-50 volume % by self-propagating high temperature synthesis (SHS) process. A composite with 11-13 volume % TiC dispersion was also synthesized through remelting and dilution. The composites were observed to contain a copper matrix together with a Cu-Ti intermetallic compound, TiC dispersoid particles and partially reacted graphite. The regions showing partially reacted graphite (carbon) became less prominent in the diluted composites. Al addition led to the refinement of TiC particles, higher hardness, reduced density and improved degree of formation and better homogeneity of the distribution of TiC particles. Dilution caused reduced hardness, while the density followed a reverse trend.
10.1016-j.msea.2008.10.038	16	wear; composite; composites; powders; milling; particles; powder; wt; sliding; friction; hardness; matrix; mechanical; surface; properties	In this paper, Cu-20vol%NbC composite was prepared by in situ and ex situ Processing methods. In in situ method, a mixture of Cu-Nb-C was mechanically alloyed in a high energy planetary mill while in ex situ method, a mixture of Cu-NbC powder was mixed in a low energy ball mill. Consolidation of the composite powder was systematically studied by pressing the powder at different compaction pressures, i.e. in the range of 350-650 MPa, followed with sintering at 900 degrees C for an hour. The presence of the NbC particle in copper matrix of the Cu-Nb-C sintered sample has been confirmed by X-ray diffraction and energy dispersive X-ray analysis. in situ composite has higher hardness and electrical conductivity than its counterpart due to a homogenous distribution of fine NbC particle and good NbC-Cu adhesion bonding. Higher compaction pressure has increased the hardness, electrical conductivity and density of the composites.
10.1016-j.msea.2008.12.050	-1		The microstructures and tensile deformation behavior of Cu-16 wt% Ag binary alloy with coarse grains were investigated by electron backscattered diffraction (EBSD) and scanning electron microscope (SEM). No precipitate was found in both eutectic Cu and Ag phases, whereas abundant precipitates were observed in proeutectic Cu matrix. Slip bands appear in the dendrites, though they are abundant in precipitates, and this can be attributed to the cube-on-cube orientation relationship and the coplanar slip systems between them. Slip bands can penetrate continuously through the eutectic region and the dendrites. The EBSD results revealed that they always had the same orientation. The tensile stress-strain curves displayed certain work-hardening behavior and high elongation. The highly continuous slip deformation mode and the good strain compatibility between matrix and the eutectic region will be beneficial to the high elongation of the Cu-Ag alloy.
10.1016-j.msea.2009.03.044	4	transformation; martensite; martensitic; phase; shape; beta; memory; shape memory; temperature; temperatures; martensitic transformation; gamma; transformation temperatures; effect; thermal	CuZnAl alloys show pseudoelasticity, shape memory behavior and if adequately treated also the two way shape memory effect (TWSME), i.e., shape change due to the martensitic transition both during cooling and by heating. The origin of this phenomenon has been strongly discussed and the role that diffusion and dislocations play on the introduction of the TWSME has been and still is discussed in the literature. However many of the reported training or educational methods show the overlapping of dislocation generation and diffusion both in the austenite and in the martensite. This work deals with the introduction of the TWSMF in CuZnAl single crystals by pseudoelastic cycling at temperatures low enough to disregard the contribution of diffusion, which influences the martensitic bcc-M18R transition at temperatures as low as room temperature in these alloys. The microstructure responsible for the introduction of the TWSME is discussed and the analysis of the effect of dislocation arrays, retained martensite, precipitates and microplasticity is presented.
10.1016-j.msea.2009.03.047	-1		The microstructure of Cu-3 at% Ti alloy aged at 773 K in a hydrogen atmosphere of 0.37 MPa has been investigated, together with hardness and tensile strength . At the early stage of aging, needle-shaped alpha-Cu4Ti particles precipitate finely in a similar manner to the case of conventional vacuum-aging. On further aging, some alpha-Cu4Ti precipitates are extended, while others are replaced by delta-TiH2 precipitates. The precipitation of titanium hydride reduces the concentration of Ti in the matrix more efficiently than aging in a vacuum. The yield strength first rises, but falls on further aging. This is due to the microstructural evolution: alpha-Cu4Ti particles first form and grow, but then diminish because of the formation of titanium hydrides. Elongation to fracture, as well as the electrical conductivity, is promoted by long-time aging in the hydrogen atmosphere, reflecting the reduced Ti concentration in the matrix.
10.1016-j.msea.2009.03.065	-1		An Ag-10 wt%Cu in situ microcomposite was produced by heavy deformation technique. Both isochronal and isothermal annealing were applied to study the microstructures, properties and thermal stability of this composite. A certain precipitation strengthening was observed during isochronally annealing at 200 degrees C. When the annealing temperatures were above 300 degrees C, continuous Cu filaments formed during heavily deformation were gradually transformed into Cu particles aligning along the wire axis because of some processes such as recrystallization and grain growth happened. The mechanical strength of this microcomposite decreased and electrical conductivity increased during annealing process in this temperature range. Electrical conductivity was used to measure the degree of transformation during the isothermal process. Combined with the Komolgorov-Johnson-Mehi-Avrami model, activation energy of 122.5 +/- 6.5 kJ/mol was determined for this process. The reason for relatively low activation energy is also discussed.
10.1016-j.msea.2009.04.006	11	glass; bulk; metallic; bulk metallic; gfa; bmg; glassy; metallic glass; ability; bulk metallic glass; amorphous; addition; crystallization; mm; glass-forming	In this study, (CuZr)(95)Al-5 and (CuZr)(90)Al-10 alloy plates with thickness of I mm were prepared by suction cast. Microstructural characterization shows that (CuZr)(95)Al-5 plate contains strip-like martensite phase and the (CuZr)(90)Al-10 plate contains sparse CuZr nanocrystals distributed at the amorphous matrix. Thermal stabilities of the two alloys were measured by DSC. For the evaluations of mechanical properties, rectangular blocks and dogbone specimen were cut off from the alloy plates and used for room temperature compression and tensile tests respectively. It reveals that significant work hardening with 5.5% plastic strain before failure were obtained for (CuZr)(95)Al-5 under compression tests, while (CuZr)(90)Al-10 exhibits very little plasticity. In tension, both alloy plates exhibit high fracture strength before catastrophic failure. The interaction between the shear bands and martensite phase were studied and the deformation behavior of the both alloys was discussed.
10.1016-j.msea.2009.05.047	-1		This study is intended to determine the effect of microstructure on internal friction and Young's modulus as a function of stress in the elastic region of an aged Cu-Be alloy and to investigate the influence of transformed phases caused by precipitation hardening on both properties. Results show that internal friction and Young's modulus were influenced by different precipitates. Transformed phases and micromechanical mechanisms could be responsible for the changes in internal friction and Young's modulus. The microstructure of the alloy having Guinier-Preston zones appears to have low internal friction and dependence on stress after aging at 315 degrees C for 2 h . The Young's moduli of the long-term aged samples increased by approximately 2 GPa compared to that for the short-term aged samples and elastic instability up to a stress of 20% of the yield strength was observed.
10.1016-j.msea.2010.01.042	6	grain; deformation; strain; strength; dislocation; cu-; tensile; size; ecap; grain size; sfe; ductility; hardening; high; stress	The strain softening behavior of a particle-containing copper alloy and the associated microstructure changes were investigated as a function of strain rate (epsilon) over dot and analyzed by modeling. It is shown that, increasing strain rate (epsilon) over dot favors the multiple peak type behavior for flow stress and the appearance of strain softening behavior. During the ambient compression, the fiber structure, dislocation density and dislocation cell size and shape were also changed significantly with increasing of strain rates (epsilon) over dot. The transition from strengthening to softening was explained in terms of generation and annihilation of dislocations within dislocation cells or at cell boundaries. A new constitutive equation was developed to well describe the strain softening in the particle-containing alloy compressed at different strain rates.
10.1016-j.msea.2010.02.076	6	grain; deformation; strain; strength; dislocation; cu-; tensile; size; ecap; grain size; sfe; ductility; hardening; high; stress	Mechanical properties of nanostructured (NS) materials are significantly affected by both grain size and twin density, and the twin density has a close relationship with the grain size. Therefore, it is fundamentally important to understand the influence of grain size on the density of deformation twins in NS materials. In this study, we selected Cu-30%Zn alloy as a model material to study this phenomenon, because it has low stacking fault energy of 7 mJm(-2) and twinning is its dominant deformation mechanism. High-pressure torsion (HPT), equal channel pressing (ECAP) and ECAP followed by rolling were used to achieve a wide range of grain size from about 3 mu m to 70 nm. It is found that, with decreasing grain size, the average distance between deformation twins decreases gradually from 177 nm to 24 nm, while the density of deformation twins (the length of twin boundary in unit area) exhibit a maximum value at ECAP + 95% rolling sample with average grain size of 110 nm. Careful statistics analysis reveals two optimum grain size ranges 60-80 nm and 40-50 nm for maximum twin density values for ECAP + 95% rolling and HPT Cu-30%Zn samples, respectively. The underlying mechanisms governing the influence of grain size on twinning is discussed.
10.1016-j.msea.2010.04.036	6	grain; deformation; strain; strength; dislocation; cu-; tensile; size; ecap; grain size; sfe; ductility; hardening; high; stress	A recent model developed to predict the smallest grain sizes obtainable by severe plastic deformation has worked well for materials with medium to high stacking fault energies (SFEs) but not for those with low SFEs. To probe this issue, experiments were conducted using a Cu-30 wt% Zn alloy with a very low SFE of 7 mJ/m(2) as the model material. High-pressure torsion was used as the grain refinement technique. The results indicate that stacking faults and twin boundaries play a key role in the grain refinement process such that the smallest achievable grain size is determined by the highest stacking fault and twin density that the system is able to produce. An amorphization of grain boundaries was also observed in the final structure. These observations are very different from those reported for materials having medium to high SFEs and they confirm the operation of a different grain refinement mechanism.
10.1016-j.msea.2010.04.070	-1		The mechanical properties and electrical resistivity of nanocrystalline copper reinforced by 1 vol.% and 5 vol.% of nano-alumina particles have been measured. The composites were prepared by ball-milling and consolidated by a combination of hot extrusion and HIPing. The uniaxial tensile and compressive strengths are comparable for each composite, and an elastic, ideally plastic response is observed. Shear bands, of width a few microns, accompany plastic deformation. A number of microstructural characterisation tools were used to reveal that grain boundary strengthening and dispersion strengthening are the dominant strengthening mechanisms. Nano-indentation measurements reveal a size effect in hardness. The electrical resistivity is almost double that of pure oxygen free copper and this is mainly ascribed to the presence of dissolved iron.
10.1016-j.msea.2010.05.074	11	glass; bulk; metallic; bulk metallic; gfa; bmg; glassy; metallic glass; ability; bulk metallic glass; amorphous; addition; crystallization; mm; glass-forming	The structure, thermal stability and tensile properties of (Cu0.5Zr0.5)(100-x)Al-x (x = 5, 6, 8) bulk metallic glasses have been investigated. A good correlation between glass transition and Young's modulus was observed. Moreover, the (Cu0.5Zr0.5)(100-x)Al-x (x = 5, 6, 8) bulk metallic glasses investigated in this work show a unique deformation behaviour in tension: next to a high fracture strength the specimens exhibit a detectable ductility before catastrophic failure. Deformation-induced nanocrystallization and formation of twins in the nanocrystals are believed to play a key role in enhancing the mechanical properties. Scanning electron microscope observations reveal a combination of vein-like patterns and cores with radiating veins on the tensile fracture surface.
10.1016-j.msea.2010.07.051	-1		Previous work has shown that rolling of an extruded Cu-8Cr-4Nb (GRCop-84) alloy results in higher steady-state creep rates over a range of stresses, leading to concern that other post-processing methods could have substantial deleterious effects on creep properties. To explore that possibility, constant-stress creep tests were conducted at 773 K on rolled GRCop-84 after it was subjected to either friction stir welding (FSW) or a 24 h 1073 K simulated-life heat treatment. The FSW had no measurable effect on the creep rate of the rolled material, but did have detrimental effects on the creep ductility caused by softening, and thus strain localization, in the heat-affected zone of the weld. The simulated-life heat treatment decreased the steady-state creep rate by approximately 45% as compared to the rolled material, leading to longer creep life at a particular applied stress. Electron backscatter diffraction methods were used to compare the microstructural features of extruded, rolled and annealed material forms. It was determined that the rolling procedure decreased the grain size, and decreased the intensity of the texture as compared to the extruded form. The simulated-life heat treatment allowed for the substantial development of twins along with minor grain growth, and a substantial decrease in texturing.
10.1016-j.msea.2010.08.015	6	grain; deformation; strain; strength; dislocation; cu-; tensile; size; ecap; grain size; sfe; ductility; hardening; high; stress	The effectiveness of the cryogenic (CT) rolling vis-a-vis room temperature (RT) rolling on strengthening is significantly affected by stacking fault energy (SFE) and there is an optimum SFE at which CT rolling is most effective. Studies on Al, Al alloy AA6061, Cu, Cu-4.6Al, Cu-9Al and Cu-15Al (in at%) alloys revealed that in metals with very high and very low SFEs, the strength difference between CT and RT rolled samples is <10%. The Cu-4.6Al alloy with an intermediate SFE revealed maximum enhancement of strength (25-30%). These results are explained by changes in deformation mechanisms with SFE and temperature. High SFE metals deformed by dislocation slip and low SFE metals deformed by twinning during CT and RT rolling. Metals with intermediate SFEs deformed by twinning during CT rolling but by dislocation slip during RT rolling, and this makes the CT rolling most effective over RT rolling in enhancing the strength .
10.1016-j.msea.2010.10.059	-1		Microstructure, mechanical properties and electrical conductivity of industrial Cu-0.5% alloy subjected to equal channel angular pressing (ECAP) by route A and cold rolling with and without aging treatment were investigated. The lamellar grains in thickness of 100 nm were obtained after eight ECAP passes. They were not further pancake shaped, but fragmentary and obtained less sharp boundaries with more dislocations in addition to cold rolling. After aging at 450 degrees C for 1 h, high density of dislocations and some coarse grains were observable after ECAP and the additional cold rolling, respectively. The tensile tests show that tensile strength arrived at 460 MPa and 484 MPa after four and eight passes of ECAP, respectively, the corresponding tensile strength increased to 570 MPa and 579 MPa after the additional cold rolling. However, the electrical conductivity was not more than 35% IACS. It was proved that four passes of ECAP followed by 90% cold rolling and aging at 450 degrees C for 1 h offered a short process for Cu-0.5%Cr alloy to balance the paradox of high strength and electrical conductivity, under which the tensile strength 554 MPa, elongation to failure 22% and electrical conductivity 84% of IACS could be obtained. The high strength was explained by precipitation strengthening and fine grain strengthening.
10.1016-j.msea.2010.11.005	-1		A high strength Cu-NbC composite conductor for electrical applications was fabricated from Cu, Nb and C elemental powders using high pressure torsion (HPT). After HPT, samples showed close to full density (> 99%). SEM observations revealed that atomic scale mixing occurred in the following order: deformation of Cu particles, the formation of Cu/Nb lamellar structure, fracturing of Nb lamella into sub-micron particles and the formation of uniform structure with fine distribution of Nb particles. The in situ formation of NbC in the copper matrix during HPT was detected. Annealing at 600 and 700 degrees C resulted in substantial increases in microhardness and tensile strength and a slight decrease in electrical conductivity with increasing NbC volume fraction. The best combination of electrical conductivity (54% IACS) and tensile strength (810 MPa) ever reported for such a composite was obtained in the Cu-2 vol% NbC composite after annealing at 700 degrees C.
10.1016-j.msea.2010.11.006	16	wear; composite; composites; powders; milling; particles; powder; wt; sliding; friction; hardness; matrix; mechanical; surface; properties	In this experiment, copper-base composites reinforced with 30 nm and 5 mu m SiC particles are fabricated on the surface of a purecopper sheetvia friction stir processing (FSP). Microstructure, mechanical properties and wear resistance of friction stir processed (FSPed) materials are investigated as a function of volume fraction of SiC particles. Results show that, applying FSP, without SiC particles, increases the percent elongation significantly (more than 2.5 times) and decreases copper's strength . Adding micro- and nano-sized SiC particles decreases the tensile strength and percent elongation. Increasing the volume fraction or decreasing the reinforcing particle size enhances the tensile strength and wear resistance and lowers the percent elongation.
10.1016-j.msea.2010.12.015	-1		The thermal instability of the Fe fibers in the heavily deformed Cu-12.8 wt%Fe composites is investigated experimentally and numerically. The fiber evolution is characterized by a field emission scanning electron microscopy (FESEM). The results show that the dominant instability of the Fe fibers is the longitudinal boundary splitting which is determined by the greater cross sectional aspect ratio (width/thickness, w/t) and the larger ratio of boundary to interfacial energy (gamma(B)/gamma(S)). The longitudinal boundary splitting makes the ribbon-like Fe fibers evolve into a series of cylindrical fibers. Then the cylindrical Fe fibers undergo the instability process in terms of the breakup, growth and coarsening concurrently. The breakup times are accurately predicted by the Rayleigh perturbation model. The growth process primarily contributes to the higher increasing rate of the fiber radius during isothermal annealing at 700 degrees C than that calculated by the coarsening theory developed for cylindrical fibers, since the Cu-matrix of composites is highly supersaturated after casting/cold-working process.
10.1016-j.msea.2010.12.099	-1		H13 tool steel powder was clad on copper alloy substrate both directly and using 41C stainless steel (high Ni steel) powder as a buffer layer by direct metal deposition (DMD). Cu-steel bimetallic die casting and injection molding tools are of high interest for reduction of cycle time by efficient heat extraction due to high thermal conductivity of copper. The mechanical properties of these bimetallic structures were investigated in terms of bond strength, impact energy and fracture toughness. The bond interfaces of these claddings showed porous and crack free transition regions. The bond strength was higher in the directly clad H13 tool steel compared to the H13 tool steel clad with 41C stainless steel as buffer layer. The fracture morphology in tensile test specimens showed ductile dimple fracture. Presence of necking just below the interface depicted the softening of substrate in heat affected zone (HAZ) during cladding. The Charpy impact energy is little higher in the 41C stainless steel buffered specimens compared to the directly clad H13 tool steel specimens but the fracture toughness results showed reduction of fracture toughness in the 41C stainless steel buffered specimens due to the low strength in the tensile test. However the fracture toughness value was in the ductile region for both deposits.
10.1016-j.msea.2011.03.077	-1		The SiC particles with mean size of 5 mu m were introduced into the pure Cu joints during the friction stir welding process. After one pass processing, the distribution of SiC particle is not uniform and some pores formed around the aggregation of SiC particles. However, the particle distribution became rather uniform after two passes processing and the previous pores can be refilled. In addition, banded structure consisting of particle-rich and particle-free region can be observed in the stir zone. The particle-rich region has an average grain size of less than 2 mu m, much smaller than that of about 8 mu m in the particle-free region. Microstructural observation confirmed that the SiC particles can act as the heterogeneous nucleation site in the dynamic recrystallization of Cu grains. The SiC dispersed Cu joints exhibit a Vickers hardness of 110 HV, much higher than 70 HV in the stir zone without SIC particles.
10.1016-j.msea.2011.05.038	-1		Multiwall carbon nanotube (CNT) reinforced Cu-10Sn alloy composites were fabricated using high power lasers. Microstructural observations showed that CNTs were retained in the composite matrix after laser processing. The addition of CNTs showed improvement in strain hardening, mechanical and thermal properties of Cu-10Sn alloy. Composites with 12 vol.% CNTs showed more than 80% increase in the Young's modulus and 40% increase in the thermal conductivity of Cu-10Sn alloy. Yield strength estimates using a model based on strengthening mechanisms in metal matrix nanocomposites and thermal conductivities derived from the Maxwell-Garnett effective medium theory were found to be in good agreement with our experimental data.
10.1016-j.msea.2011.06.056	6	grain; deformation; strain; strength; dislocation; cu-; tensile; size; ecap; grain size; sfe; ductility; hardening; high; stress	Experiments were conducted on a Cu-0.1% Zr alloy in order to examine the evolution of hardness and microstructure after processing by high-pressure torsion. Disks were pressed through different numbers of revolutions up to a maximum of 10 turns using an applied pressure of 6.0 GPa. It is shown that there is a gradual evolution in both the hardness and the microstructure with increasing numbers of turns. After 5 and 10 turns there is a high degree of hardness homogeneity and the microstructure consists of well-defined equiaxed grains. The measured grain size after 5 turns was similar to 180 nm in the peripheral region of the disk. Tensile testing at 673 and 723K after processing through 5 and 10 turns showed a maximum elongation to failure of similar to 280% at 723 K using a strain rate of 1.0 x 10(-4) s(-1).
10.1016-j.msea.2011.06.062	-1		The effect of strain path change during rolling has been investigated for copper and nickel using X-ray diffraction and electron back scatter diffraction as well as crystal plasticity simulations. Four different strain paths namely: (i) unidirectional rolling; (ii) reverse rolling; (iii) two-step cross rolling and (iv) multi-step cross rolling were employed to decipher the effect of strain path change on the evolution of deformation texture and microstructure. The cross rolled samples showed weaker texture with a prominent Bs {1 1 0}< 1 1 2 > and P(B(ND)) {1 1 0}< 1 1 1 > component in contrast to the unidirectional and reverse rolled samples where strong S {1 2 3}< 6 3 4 > and Cu {1 1 2}< 1 1 1 > components were formed. This was more pronounced for copper samples compared to nickel. The cross rolled samples were characterized by lower anisotropy and Taylor factor as well as less variation in Lankford parameter. Viscoplastic self-consistent simulations indicated that slip activity on higher number of octahedral slip systems can explain the weaker texture as well as reduced anisotropy in the cross rolled samples.
10.1016-j.msea.2011.06.075	6	grain; deformation; strain; strength; dislocation; cu-; tensile; size; ecap; grain size; sfe; ductility; hardening; high; stress	Samples of Cu-Al and Cu-Zn alloys with different compositions were subjected to large strains under plane strain compression (PSC), a process that simulates the rolling operation. Four compositions in the Cu-Al system, namely 1, 2, 4.7 and 7 wt% Al and three compositions in the Cu-Zn system of 10,20 and 30 wt% Zn, were investigated. Adding Al or Zn to Cu effectively lowers the stacking fault energy (SFE) of the alloy and changes the deformation mechanism from dislocation slipping to dislocation slipping and deformation twinning. True stress-true strain responses in PSC were documented and the strain hardening rates were calculated and correlated to the evolved microstructure. The onset of twinning in low SFE alloys was not directly related to the low value of SFE, but rather to build up of a critical dislocation density during strain hardening in the early stage deformation (epsilon < 0.1). The evolution of texture was documented for the Cu-Al samples using X-ray diffraction for samples plane strain compressed to true axial strains of 0.25, 0.5, 0.75 and 1.0. Orientation distribution function (ODF) plots were generated and quantitative information on the volume fraction of ideal rolling orientations were depicted and correlated with the stacking fault energy.
10.1016-j.msea.2011.07.030	1	shape; memory; shape memory; damping; martensite; martensitic; damping capacity; transformation; capacity; strain; superelasticity; temperature; cu-al-mn; shape memory effect; effect	The microstructure transition, shape memory effect, machinability and mechanical property of the CuAlMnZn alloy with and without Te have been studied using X-ray diffraction analysis, chips observation and scanning electron microscopy (SEM), tensile strength test and differential scanning calorimeter (DSC), and semi-quantitative shape memory effect (SME) test. The particles with richer Te dispersedly distributed in grain interior and boundary with size of 2-5 mu m. After the addition of Te, the CuAlMnZnTe alloy machinability has been effectively increased to approach that of BZn15-24-1.5 and its shape memory property remains the same as the one of CuAlMnZn alloy. The CuAlMnZn shape memory alloys with and without Te both have good ductility as annealed at 700 degrees C for 15 min.
10.1016-j.msea.2011.07.050	4	transformation; martensite; martensitic; phase; shape; beta; memory; shape memory; temperature; temperatures; martensitic transformation; gamma; transformation temperatures; effect; thermal	This study aims at revealing martensitic microstructures that exist in a shape-memory alloy. Infrared thermography was used for this purpose. Experiments were performed on a Cu-Al-Be single crystal which features a pseudoelastic response at ambient temperature. The specimen was first partially transformed to martensite by mechanical loading. Then a small cyclic loading was applied while the temperature evolution on the specimen surface was captured by an infrared camera. Thermal images obtained were then processed to extract two types of quantities: the maps of heat sources produced by the material and the maps of temperature oscillation amplitudes. Two thermomechanical couplings are revealed: the thermoelastic coupling and the latent heat due to the small cyclic movement of austenite-martensite interfaces, thus highlighting the martensitic microstructure distribution in the specimen.
10.1016-j.msea.2011.07.061	16	wear; composite; composites; powders; milling; particles; powder; wt; sliding; friction; hardness; matrix; mechanical; surface; properties	Multiple hardening mechanisms of a copper matrix have been presented and discussed. The gas atomized Cu-0.6 wt%Ti-2.5 wt%TiB2 (Cu-Ti-TiB2) powders were used as starting materials. Dispersoid particles TiB2 were formed in situ in the copper matrix during gas atomization. The powders have been consolidated by hot isostatic pressing (HIP). Optical microscopy, transmission electron microscopy (TEM), and X-ray diffraction (XRD) analysis were performed for microstructural characterization of powders and composite compacts. High hardening of the Cu-Ti-TiB2 composite achieved by aging is a consequence of the simultaneous influence of the following factors: the development of modulated structure with metastable Cu4Ti(m) particles and in situ formed TiB2 dispersoid particles.
10.1016-j.msea.2011.09.069	6	grain; deformation; strain; strength; dislocation; cu-; tensile; size; ecap; grain size; sfe; ductility; hardening; high; stress	High-cyclic fatigue life in ultra-fine grained materials fabricated by equal channel angular pressing (ECAP) suffers from a specific shear texture induced during the fabrication as has been demonstrated in the present study on the example of pure copper. This texture promotes orientation of the easy glide crystallographic planes to be aligned parallel to the shear plane in ECAP. If specimens for the following fatigue tests are cut parallel to the pressing direction, the alignment of the easy glide crystallographic planes deteriorates the fatigue performance. It is demonstrated that the deteriorative effect can be alleviated through the controlled degradation of the texture. This goal can be achieved through (i) a consecutive ECAP processing up to equivalent strains of more than epsilon >= 8 requiring eight and more passes, or (ii) a pure-shear based post-ECAP processing to the equivalent strains as low as epsilon = 0.22. The second route is thought to be most effective in practical applications where improved fatigue performance is of concern.
10.1016-j.msea.2011.10.093	16	wear; composite; composites; powders; milling; particles; powder; wt; sliding; friction; hardness; matrix; mechanical; surface; properties	In this study, Cu-based shape memory alloy (Cu-12.5%Al-5%Mn in %wt) was processed by mechanical alloying in different milling conditions (2.5, 5, 10, 15 and 25 h). Prepared powders were characterized by means of X-ray diffraction (XRD), scanning electron microscopy (SEM) and transmission electron microscopy (TEM). XRD results showed that increasing milling time leads to a reduction in crystallite size and an increase in lattice parameters. After 15 h of milling, the minimum crystallite size was found to be around 7 nm, and did not change upon further processing. SEM and TEM results showed that morphology of pre-alloyed powder changed with milling time from lamella to globular and the mean size of pre-alloyed powders was around 15 nm after 15 h of milling. EDX analysis results indicated a homogeneous distribution of Mn and Al elements within the Cu matrix.
10.1016-j.msea.2011.11.005	-1		Stress evolution in Cu, Cu-1.4 at% Ag, Cu-3 at% Ag and Cu-6 at% Ag thin films was determined by substrate curvature measurements from room temperature to 400 degrees C in two cycles, each involving a heating and a cooling stage. Stress hysteresis curves for the Cu-Ag films changed slope significantly within the temperature range 220-250 degrees C and stress range 100-200 MPa during the heating stage of the first cycle; this occurred at 175 degrees C and 100 MPa for the Cu film. This was followed by stress relaxation in all the films at about 300 degrees C. For the as-deposited, annealed and thermally cycled films exposed to low temperatures (-197 to 0 degrees C), instances of yielding occurred in Cu, Cu-1.4 at% Ag and Cu-3 at% Ag films. However, the as-deposited, annealed and thermally cycled Cu-6 at% Ag film was always elastic and there was no yielding when exposed to low temperatures. Microstructural analyses revealed the presence of Cu and Ag phases in all the Cu-Ag films, irrespective of the thermal history. Despite electron diffraction revealing their existence, Ag particles were not so apparent in the microstructures of the as-deposited and annealed films probably because of their fine sizes. However, after thermal-cycling Ag particles were observed at grain boundaries and inside grains in addition to significant grain growth .
10.1016-j.msea.2011.11.019	-1		Effect of gamma(2) phase evolution on mechanical properties of Cu-14%Al-3.8%Ni (mass fraction) alloy wires fabricated by continuous unidirectional solidification technology was investigated before and after heat treated at 700-780 degrees C. Mechanism for the improvement of mechanical properties of the alloy was analyzed. It was found that the alloy retained continuous columnar grains after heat treatment. With the heat treatment temperatures increasing from 700 degrees C to 770 degrees C, the coarse dendrite gamma(2) phase evolved into the fine polygonal, ellipsoidal and spherical particles in the grains, while the long-banding, discontinuous block and ellipsoidal particles at the grain boundaries. The average size of the gamma(2) phase decreased from 20 mu m before heat treatment down to 2 mu m, and its amount reduced from 50.0% down to 0.8%. The gamma(2) phase was full dissolution at 780 degrees C. The tensile strength of the alloy treated at 700-780 degrees C ranged from 577 MPa to 710 MPa. The elongation of the alloy ranged from 7.5% to 23.8% and had a peak value at 760 degrees C. Excellent balance between strength and elongation could be obtained when the spherical gamma(2) phase was distributed throughout the alloy with the size smaller than 5 mu m and the amount in the range of 11.4-16.6%. The nano-hardness and elastic modulus of the gamma(2) phase decreased gradually with the reduction of the amount, leading to the improvement of mechanical properties.
10.1016-j.msea.2011.12.005	-1		Considering the mismatch of coefficient of thermal expansion (CTE) of Cu and W phase and temperature gradient, internal and external thermal load are applied on meso-scale 2D representative volume element (RVE) of CuW alloys under thermal shock, respectively. Void volume fraction (VVF) and VVF induced crack are determined by finite element method (FEM) utilizing Gurson-Tvergaard-Needleman (GTN) model, and the driving forces for damage nucleation and growth are analyzed with normal and shear stress as well. The simulation results show that damage and damage induced crack initiate from the vertex of W grain and grow along W/Cu interface, then propagate into Cu phase. After thermal shock experiment on CuW specimen by high voltage arc, micro cracks present along W/Cu interfaces and inside Cu phase, which is in good agreement with simulation results.
10.1016-j.msea.2011.12.098	6	grain; deformation; strain; strength; dislocation; cu-; tensile; size; ecap; grain size; sfe; ductility; hardening; high; stress	The microstructure and mechanical behaviour of a Cu-Cr-Zr alloy has been examined after severe plastic deformation, and giving both prior and subsequent age hardening treatments. Dislocation subgrain structures are produced by deformation leading to high strength and reduced ductility. Mild annealing following deformation leads to slight substructural coarsening, some loss of dislocations, and simultaneous precipitation, resulting in an increase of strength with some improvement of ductility. The same heat treatments for precipitation before deformation lead to finer substructures, with shear reducing particle size and leading to partial dissolution. Strength and ductility are analysed in terms of the deformation substructures and the role of precipitate particles.
10.1016-j.msea.2011.12.104	-1		A strong alpha-fiber I texture with components from {001} < 1 1 0 >(beta 1) to {1 1 2} < 110 >(beta 1) was developed in a polycrystalline Cu-13Al-5.5Ni-1Ti (wt%) shape memory alloy by hot extrusion at 800 degrees C (followed by recrystallization). Nearly fully recoverable strains up to the order of 6%, associated with cubic to monoclinic martensitic transformation beta(1)->beta(1)' have been measured by thermal cycling under constant load experiments. Such a degree of strain recovery is typical of single crystals or polycrystalline arrays with a low degree of grain constraint, such as highly textured, bamboo like, extruded materials. The reversible transformation strains reached about 68% of the upper bound predicted by a Sachs-type model which averages the most favorable martensite variants in each grain, taking into account their orientation and disregarding interactions between them. Due to the strong texture introduced in the material, such high values of recoverable transformation strains are obtained even for specimens having a grain size/thickness ratio of similar to 0.05, producing relatively high grain constraint.
10.1016-j.msea.2012.01.047	-1		Cu-Cr system alloy strips were manufactured by an online hot rolling-quenching (HR-Q) process and subsequent thermomechanical treatments. The microstructure and properties of the alloys were investigated by observations of optical microscopy and transmission electron microscopy, and measurements of microhardness and electrical conductivity. The results show that the HR-Q process and thermomechanical treatments are successfully developed to manufacture Cu-Cr system alloy strips with good combinations of strength, conductivity and softening resistance. Ordered fcc structure Cr precipitates, which are decomposed from the thermomechanical treated alloys, are considered to be precursors to the formation of equilibrium bcc Cr precipitates and responsible for the improvement of properties during near peak aging. Small additions of Zr, Mg and Si effectively improve the hardness and softening resistance of Cu-Cr alloy, and slightly reduce the electrical conductivity. The achievement of high strength and high electrical conductivity in the alloys is ascribed to the interactions of grain boundary strengthening, strain hardening and precipitation hardening.
10.1016-j.msea.2012.03.078	-1		The effect of solute segregation on thermal creep in dilute nanocrystalline alloys (Cu-Nb, Cu-Fe, Cu-Zr) was studied at elevated temperatures using molecular dynamics simulations. A combined Monte-Carlo and molecular dynamics simulation technique was first used to equilibrate the distribution of segregating solutes. Then the creep rates of the diluted Cu samples were measured as functions of temperature, composition, load and accumulated strain. In Cu-Nb samples, the creep rates were observed to increase initially with strain, but then saturate at a value close to that obtained for alloys prepared by randomly locating the solute in the grain boundaries. This behavior is attributed to an increase in grain boundary volume and energy with added chemical disorder. At high temperatures, the apparent activation energy for creep was anomalously high, 3 eV, but only 0.3 eV at lower temperatures. This temperature dependence is found to correlate with atomic mobilities in bulk Cu-Nb glasses. Calculations of creep in nanocrystalline Cu alloys containing other solutes, Fe and Zr, show that the suppression of creep rate scales with their atomic volumes when dissolved in Cu.
10.1016-j.msea.2012.03.105	16	wear; composite; composites; powders; milling; particles; powder; wt; sliding; friction; hardness; matrix; mechanical; surface; properties	This work studied the structural evolution of Cu-xMo (x = 5 and 8 wt%) alloys processed by mechanical alloying using x-ray diffraction profiles, scanning electron microscopy, differential scanning calorimetric and microhardness. X-ray diffraction analysis was done using the modified Williamson-Hall and Warren-Averbach methods. These were used to determine structural properties, such as crystallite size, stacking fault probability and energy, dislocation density of metallic powder as a function of the amount of Mo and milling time. The main results obtained for both alloys were higher dislocation density and Vickers microhardness values were measured and crystallites sizes of around 10 nm were measured for both systems at 50 h of milling. Lattice defects increase the free energy and the free energy curves shift upwards, therefore the solubility limits change and Cu-Mo solid solution is formed.
10.1016-j.msea.2012.07.022	6	grain; deformation; strain; strength; dislocation; cu-; tensile; size; ecap; grain size; sfe; ductility; hardening; high; stress	Experiments were conducted on a Cu-0.1% Zr alloy to evaluate the potential for achieving homogeneity when processing by equal-channel angular pressing (ECAP). Billets of the alloy were processed by ECAP for up to 8 passes at room temperature using a die with a channel angle of 110. This processing reduced the grain size from an initial value of similar to 30 mu m to a value of similar to 500 nm after 8 passes. Values of the Vickers microhardness were recorded on both the cross-sectional or X planes and the longitudinal or Y planes after ECAP. The results reveal the presence of lower hardness values adjacent to the lower surfaces of the billets in the early stages of processing but there is an evolution towards a hardness homogeneity throughout the billets after pressing through 8 passes. The measurements show this evolution occurs at similar rates on the X and Y planes.
10.1016-j.msea.2012.07.044	16	wear; composite; composites; powders; milling; particles; powder; wt; sliding; friction; hardness; matrix; mechanical; surface; properties	Powder Metallurgy is used widely to produce Cubased shape memory alloys having maximum of desired properties. It is better to use P/M to produce nearnet shape alloy products and have better controllability on the composition and grain size. In this study, the highenergy planetary ball milling was applied to convert the elemental powder mixtures of Cu, Al and Ni into prealloyed powders. The effect of milling time on composition and particles size distribution was studied and the prealloyed powders were compacted by pressing and then hot extruded to obtain the final alloy sample. Strain recovery of the bended samples was studied to evaluate the effect of milling on shape memory properties. The densities of samples were calculated in green, sintered and extruded conditions to investigate the changes in the density of the samples, and influence of porosity on shape memory effect. The results showed that milling time has a variable influence on the density of samples, which can takes effect on the shape memory recovery due to amount of porosity.
10.1016-j.msea.2012.07.071	8	hot; deformation; strain; strain rate; dynamic; hot deformation; recrystallization; dynamic recrystallization; flow; rate; flow stress; compression; constitutive; degrees; stress	The effect of initial microstructure, strain rate and temperature on compression behavior of Cu-0.23 vol% Al2O3 alloys was investigated. A typical flow stress oscillation phenomenon appears in both the transverse and longitudinal high strain rate compressions. The change of microhardness characteristics was observed and explained by competing processes of work hardening and work softening. The constitutive equations of Cu-0.23 vol% Al2O3 alloy compressed under different conditions were established. The microstructure evolution in transverse and longitudinal compressions is significantly different due to the different rates of nucleation and grain growth during the dynamical recrystallization. The number of dynamical recrystallization grains in the longitudinal compression is much higher than in the transverse compression, and the longitudinal microstructure is relatively homogeneous. The flow stress oscillation phenomenon affected by the strain rate, temperature and initial microstructure was observed in this study, its difference between the transverse and longitudinal compressions was also demonstrated.
10.1016-j.msea.2012.10.014	17	wear; composites; coating; friction; composite; coatings; surface; tribological; properties; wear resistance; resistance; powder; sliding; matrix; wear rate	Cu-MoS2-graphite-WS2 nanotubes composites were fabricated by the P/M hot pressing method. The tribological properties and contact voltage drops of the composites were investigated using a block-on-ring friction and wear tester in air and vacuum respectively, rubbing against Cu-5 wt% Ag alloy ring with different electric current. Tribo-films formed on the worn surfaces were characterized by scanning electron microscopy (SEM) and X-ray photoelectron spectroscopy (XPS). Results illustrated that the friction coefficients and wear rates in air were lower than those in vacuum due to the synergistic effect of lubrication from the mixture of MoS2 and graphite in air and the limited lubrication properties of graphite in vacuum. The friction coefficients and wear rates increased gradually with the increasing current density because of the additional Joule heat resulting from the release of current. The contact voltage drops were low in the initial stage, and then increased to a stable value owing to the gradual formation of tribo-films on the sliding surface which changed the nature asperities from metal-metal to metal-film-metal type on the contact interfaces of composites and rings.
10.1016-j.msea.2012.10.062	16	wear; composite; composites; powders; milling; particles; powder; wt; sliding; friction; hardness; matrix; mechanical; surface; properties	The densification behavior of oxidized Cu-8 at% Cr-4 at%Nb alloy powders by vacuum hot pressing and subsequent mechanical properties of alloy compares well with that of fresh powders with no oxides and hydrogen reduced powders sintered using same conditions. The reason for such observation is the presence of high vacuum and carbon atmosphere due to graphite die at the furnace temperature helping in the decomposition of oxide layer. Reduction of oxides of copper controls the overall densification process. A new mechanism for the densification of air-oxidized powders during vacuum hot pressing is also put forward. Present work indicates that reduction of powders is not needed if consolidated by vacuum hot pressing.
10.1016-j.msea.2012.11.036	11	glass; bulk; metallic; bulk metallic; gfa; bmg; glassy; metallic glass; ability; bulk metallic glass; amorphous; addition; crystallization; mm; glass-forming	Starting from the brittle Cu46Zr46Al8 bulk metallic glass (BMG), the effect of substituting Al by Ti on the glass-forming ability (GFA) and the mechanical properties is systematically investigated. The supercooled liquid region (Delta T-x), the reduced glass transition temperature (T-rg=Tg/T-lig) and the gamma parameter (gamma=T-x/(T-g+T-liq)) tend to decrease with increasing Ti content in the present Cu46Zr46Al8-xTix (0 <= x <= 8) alloys. An increasing distance from the eutectic point might be the origin of the reduced GFA after the Ti addition. At the same time, the Ti additions significantly increase the plasticity of the respective alloys. The Cu46Zr46Ti3.2Al4.8 bulk glassy alloy is found to have the largest plastic strain in compression of around 12% and a fracture strength up to 1950 MPa while the Ti-free Cu46Zr45Al8 BMG exhibits values of 0% and 1754 MPa, respectively. The statistics of the serrated flow behavior, which is closely related with the dynamics of shear bands, are also investigated. The macroscopic and microscopic mechanisms, which contribute to the enhancement of malleability, are analyzed.
10.1016-j.msea.2012.11.048	6	grain; deformation; strain; strength; dislocation; cu-; tensile; size; ecap; grain size; sfe; ductility; hardening; high; stress	A bulk Cu-Ag-Zr alloy was processed by high-pressure torsion (HPT) up to 20 revolutions. The microstructure and microhardness of these deformed samples were studied after annealing. Microstructure refinement and grain growth have been observed at different straining stages. Accordingly, the microhardness increases initially and decreases slightly at extremely high strains. Deformation-induced mechanical alloying has also been detected. When the supersaturated solid solution was annealed at different temperatures, it is found that the microhardness increases slightly at 125 degrees C and then decreases continuously with increasing the annealing temperature. When the disks processed by HPT for one and five revolutions were annealed at 125 degrees C, microhardness decreases near the center but increases at the outer region of the disk, and this transition is proposed to be strain-related.
10.1016-j.msea.2012.11.091	-1		Cu55Zr35Ti10 (at%) glassy ribbon was prepared by melt spinning. The effect of the tension on its thermal and corrosive properties was investigated by differential scanning calorimetry and electrochemical polarization experiments, respectively. After the tension, the crystallization procedure including crystallization temperature and crystallization enthalpy of Cu55Zr35Ti10 metallic glass hardly maintains the same, while the relaxation temperature and glass transition temperature decrease. In addition, the activation energies of the glass transition and the relaxation decrease. On the other hand, corrosion potentials polarized in all studied solutions sharply increase, while the corrosion current densities decrease. The corroded surface micrographs in all studied solutions are remarkably changed. In addition, the difference of corrosive behavior in 0.5 M H2SO4, 1 M HCl, and 1 M NaCl is also discussed.
10.1016-j.msea.2013.01.059	8	hot; deformation; strain; strain rate; dynamic; hot deformation; recrystallization; dynamic recrystallization; flow; rate; flow stress; compression; constitutive; degrees; stress	Hot deformation tests of the Cu-0.6Cr-0.03Zr alloy were performed on a Gleeble 1500 system with various strain rates at different deformation temperatures. The flow stress was employed to analyze the effect of work hardening, dynamic precipitation coarsening and dynamic recrystallization on deformation behaviors. The microstructures evolution was observed, after which the thermal deformation activation energy was calculated as 572.053 kJ/mol and constitutive equation was established. The processing map was established to obtain the optimum domain occurred at 770-800 degrees C and 0.01-0.05 s(-1) for hot working.
10.1016-j.msea.2013.01.063	-1		Cu-Al-Ni high temperature shape memory alloy (HTSMA) strips were successfully prepared from rapid solidified water atomized Cu-Al-Ni pre-alloyed powders via hot densification rolling of unsheathed sintered powder preforms. Finished heat-treated Cu-Al-Ni alloy strips had fine-grained structure, average grain size approximately 16 mu m, and exhibited a combination of high strength and high ductility. It has been demonstrated that the redistribution of nano-sized alumina particles, present on the surface as well as inside the starting water atomized Cu-Al-Ni pre-alloyed powder particles, due to plastic deformation of starting powder particles during hot densification rolling resulted in the fine grained microstructure in the finished SMA strips. The finished SMA strips were almost fully martensitic in nature, consisting of a mixture of beta(1)' and gamma(1)' martensite. The average fracture strength and fracture strain of the finished SMA strips were 810 MPa and 12%, respectively, and the fractured specimens exhibited primarily micro-void coalescence type ductile nature of fracture. Finished Cu-Al-Ni SMA strips exhibited high characteristic transformation temperatures and an almost 100% one-way shape recovery was obtained in the specimens up to 4% applied deformation pre-strain. The retained two-way shape memory recovery increased with increasing applied training pre-strain, achieving a maximum value of 16.25% at 5% applied training pre-strain.
10.1016-j.msea.2013.02.020	-1		The microstructural evolution and deformation mechanism of the 80 W-20Cu alloy at ultra-high strain rates under explosive loading were systematically investigated. During the deformation process, the W skeleton with high strength was fragmented into W particles, and the W particles were slightly elongated. The Cu matrix was severely deformed and significantly contributed to coordinating the deformation of the 80 W-20Cu alloy. Under ultra-high stain rate conditions, the deformation mechanism of the Cu matrix undergoes dynamic recrystallisation, a process in which dislocation movement plays a dominant role instead of twinning. A novel structure of high-density dislocation walls was found in the deformed Cu matrix. Analysis shows that under the conditions of ultra-high strain rate loading, high-density dislocation walls composed of parallel dislocation lines are generated in Cu grains that subsequently turn into large angular boundaries. Large angular boundaries ultimately transform into refined grain boundaries, and thus, grain refinement is accomplished. Crown Copyright
10.1016-j.msea.2013.04.004	6	grain; deformation; strain; strength; dislocation; cu-; tensile; size; ecap; grain size; sfe; ductility; hardening; high; stress	Experiments were conducted to evaluate the evolution of hardness and microstructure in a commercial Cu-2.5Ni-0.6Si alloy (in wt%) after processing using High-Pressure Torsion (HPT) at room temperature with an imposed pressure of 6.0 GPa and Equal-Channel Angular Pressing (ECAP) at 423 K using a channel angle of 135 degrees. Hardness measurements, X-ray diffraction and transmission electron microscopy (TEM) were used for microstructural evaluation and the results show a general consistency between these various techniques. The changes in the crystallite size and the dislocation structure as a function of the number of HPT revolutions and ECAP passes are discussed and compared with the results of the TEM observations. The detailed microstructural observations show a gradual evolution with increasing numbers of revolutions and passes with a saturation after 3 turns of HPT but with no saturation attained in ECAP even after 12 passes because of the lower imposed strain.
10.1016-j.msea.2013.04.031	-1		Anelastic and viscoplastic characteristics of Cu50Zr50 and Cu65Zr35 binary bulk metallic glasses at room temperature were examined through nanoindentation creep experiments. Results show that both the deformations are relatively more pronounced in Cu50Zr50 than in Cu65Zr35, and their amount increases with the loading rate. The results are analyzed in terms of the influences of structural defects and loading rate on the room temperature indentation creep.
10.1016-j.msea.2013.04.037	4	transformation; martensite; martensitic; phase; shape; beta; memory; shape memory; temperature; temperatures; martensitic transformation; gamma; transformation temperatures; effect; thermal	Mechanical damping applications could benefit from the large hysteresis, large pseudoelastic strain and the fact that the transformation stresses of the 18R <-> 6R martensite-martensite transformation depend very little on temperature in Cu-based alloys. This work presents the 18R <-> 6R mechanical cycling behavior of CuZnAl shape-memory alloy single crystals with electronic concentration e/a=1.48. A fine distribution of gamma phase nanoprecipitates is introduced to prevent plastic deformation of the 6R phase. Results show that, although significant 6R stabilization is observed at very low frequencies (below 10(-2) Hz), it is possible to obtain more than 1000 stable pseudoelastic cycles with only minor changes in transformation stresses and hysteresis width at frequencies above 10(-1) Hz. A more pronounced decrease in transformation stresses is observed after 1000 cycles. Nevertheless, the decrease in hysteresis is small up to 2000 cycles. Reported and present results indicate that pair interchange of atoms can explain the stabilization of 6R under quasistatic experimental conditions. However, at higher frequencies of cycling, stabilization of this martensite shows additional features, leading to a dynamic stabilization with slight effects on the mechanical behavior at the required frequency and number of cycles. On the whole, the behavior of this transformation is unique and very promising.
10.1016-j.msea.2013.05.010	6	grain; deformation; strain; strength; dislocation; cu-; tensile; size; ecap; grain size; sfe; ductility; hardening; high; stress	A Cu-0.1% Zr alloy was processed by equal-channel angular pressing (ECAP) for up to 8 passes and the samples processed through 4 and 8 passes were then sectioned into disks and further processed by high-pressure torsion (HPT) for 5 turns. Measurements were taken for the microhardness distributions on cross-sectional planes of the ECAP billets and on the HPT disks and the microstructures were examined using transmission electron microscopy and electron back-scatter diffraction. The results demonstrate that a combination of ECAP and HPT leads to additional grain refinement, higher hardness values and a larger fraction of boundaries having high angles of misorientation. The minimum average grain sizes recorded in these experiments were similar to 280 and similar to 260 nm at the center and edge of a disk, respectively, after processing through 8 passes of ECAP and 5 turns of HPT. The results contrast with an earlier report using high-purity Cu where a combination of ECAP and HPT gave a mixture of ultrafine and coarse grains due to the occurrence of dynamic recrystallization during the torsional straining.
10.1016-j.msea.2013.05.067	6	grain; deformation; strain; strength; dislocation; cu-; tensile; size; ecap; grain size; sfe; ductility; hardening; high; stress	Pure Cu, Cu-5 at%Al, Cu-10 at%Al and Cu-15 at%Al with different stacking fault energy (SFE) of 78, 37, 7 and 5 mJ/m(2), respectively, were processed through split Hopkinson pressure bar (SHPB) with the strain rate of 10(3)/sec. The influence of high strain rate on the evolution of microstructures and mechanical properties of Cu and Cu-Al alloys was investigated. X-ray diffraction measurements indicate that, the microstructures of Cu and Cu-Al alloys have been refined to the nano scale after deformed by SHPB, and with decreasing SFE, the average grain size decreases gradually from 72 to 40 nm, while the dislocation density increases from 0.55 x 10(14) to 4.4 x 10(14) m(-2) and the twin density increases from 0.04% to 1.07%. The formation of deformation twins is an additional factor that contributes to the microhardness and strength of Cu and Cu-Al alloys except the solid solution strengthening effect. Cu-15 at%Al has the biggest strain hardening rate at larger strains due to its lowest SFE which results in the highest twin density. The results confirm that lower SFE improves both strength and strain hardening rate of materials.
10.1016-j.msea.2013.06.046	6	grain; deformation; strain; strength; dislocation; cu-; tensile; size; ecap; grain size; sfe; ductility; hardening; high; stress	Creep crack growth (CCG) has been studied in phosphorus-alloyed oxygen-free copper (Cu-OFP) at 22, 75, 175, and 215 degrees C with compact tension (CT) specimens. At 175 and 215 degrees C, the cracks grew about 10 mm before final instantaneous failure. In contrast, there was no visible crack growth at 22 and 75 degrees C. Strongly deformed grains were observed adjacent to the cracks at 175 and 215 degrees C. Intergranular creep cavities were found around the cracks. At 22 and 75 degrees C, deformed grains and some cavities as well as microcracks were observed close to the crack tip. A model for crack propagation based on creep damage formation has been formulated to interpret the test results. Rupture criteria based on both creep ductility exhaustion and grain boundary cavitation were taken into account. The contribution from the ductility exhaustion to the creep damage dominated at the lower two test temperatures whereas the contribution from grain boundary cavitation at the higher test temperatures. The model can describe the influence of temperature on the observed creep crack propagation. It can also account for the observed cavitation in a qualitative way.
10.1016-j.msea.2013.06.050	6	grain; deformation; strain; strength; dislocation; cu-; tensile; size; ecap; grain size; sfe; ductility; hardening; high; stress	Influence of nano-scale grain boundaries (GB) on the mechanical behavior and Bauschinger's effect in copper during cyclic loading, in comparison with those of Cu single crystal (SC) and Cu with nano-scale twin boundaries (TW), was computationally investigated employing the molecular dynamics simulation technique. It was shown that Bauschinger's effect in the nano-systems was gradually weakened in the following order: SC, GB and TW. The annihilation of dislocations or partial dislocations with opposite signs and the shrinkage/extension of associated stacking faults upon stress reversal were mainly responsible for Bauschinger's effect in the nano-copper systems. The cyclic loading process increased the failure strain of the GB, TW and SC systems. However, the increase in the failure strain was less profound in the GB and TW systems. This could be attributed to the fact that both the grain and twin boundaries can block the dislocation movement and stacking fault extension, resulting in higher stress concentration at the boundaries to promote failure.
10.1016-j.msea.2013.07.005	-1		The microstructures and tensile properties of two ultrafine structured Cu-5vol%Al2O3 nanocomposite samples made by a combination of high energy mechanical milling of a mixture of Cu powder and gamma Al2O3 nanopowder and powder compact extrusion were studied. The sample extruded at 750 degrees C exhibited a microstructure consisting of Cu grains with sizes in the range of 100-500 nm and a dispersion of Al2O3 nanoparticles with sizes in the range of 20-345 nm. With the extrusion temperature increasing to 900 degrees C, the Cu grain sizes remained almost unchanged, but a large fraction of the Al2O3 nanoparticles were dissolved, leading to possible formation of nanometer sized AL(3+)/O2- clusters. This microstructural difference of the two samples causes an interesting difference in tensile properties, with the sample extruded at 900 degrees C showing approximately 150 MPa higher yield strength and ultimate tensile strength and also better ductility than the sample extruded at 750 degrees C. It appears that this significant beneficial effect of dissolution of Al2O3 nanoparticles is mainly caused by the significant strengthening effect of the nanometer sized Al3+/O2- clusters through Orowan mechanism.
10.1016-j.msea.2013.07.018	6	grain; deformation; strain; strength; dislocation; cu-; tensile; size; ecap; grain size; sfe; ductility; hardening; high; stress	The effect of an application of high hydrostatic pressure on the microstructure, nanoscale porosity and creep behaviour of high purity aluminium and a Cu-0.2 wt% Zr alloy processed by equal-channel angular pressing (ECAP) was examined with an emphasis on creep resistance and lifetime. It was found that, under the same loading conditions, specimens subjected to a subsequent high hydrostatic compression pressure prior to creep exposure exhibited longer times to creep fracture than those pressed by ECAP only. However, this impact continuously decreases with the increasing number of ECAP passes. A detailed quantitative microstructure study was conducted using TEM, SEM, electron backscatter diffraction (EBSD) and a small-angle X-ray scattering (SAXS) method and dilatometry. These analyses revealed that a general increase in the creep resistance of pressurized material may be explained by an increase in the density and the corresponding decrease in the nanoporosity of the material. Further, it was revealed that the fraction of high-angle grain boundaries increases with increasing number of ECAP passes. It is the accumulation of high-angle grain boundaries that accounts for the observed decrease in the pressurization-induced increment of creep life of the material with the increasing number of ECAP passes.
10.1016-j.msea.2013.07.074	16	wear; composite; composites; powders; milling; particles; powder; wt; sliding; friction; hardness; matrix; mechanical; surface; properties	We present a process for the production of Cu-Al matrix composites containing between 25 and 30 vol.% in situ Al2O3. The composites are prepared by pressing, heat-treating and hot working blended powders of Cu, Al and CuO packed into copper alloy cans. The evolution of the microstructure during in situ reaction is governed by the stable growth of alumina films; these mitigate the rate of reaction, preventing thermal runaway if samples are processed with sufficient thermal ballast. The resulting alumina is amenable to subsequent refinement and dispersion by hot working the composite, with reversed (extrusion/upsetting/extrusion) deformation giving best results. Cu7 wt%Al containing homogeneously distributed micron-sized alumina particles thus produced has a tensile strength of 848 +/- 44 MPa and a tensile ductility of 2.2 +/- 0.8%.
10.1016-j.msea.2013.08.004	-1		Open-celled metal foams have received considerable attention in various fields and are expected to be used as engineering materials where heat exchange, sound absorption and filtration are required. In this study, Cu foam specimens with NaCl volume fractions of 60%, 70% and 80% were successfully fabricated by the friction powder compaction (FPC) process with the sintering and dissolution process (SDP) using NaCl as space holders. In the FPC process, no external heat source was used for fabricating Cu foam except for the friction heat generated by the rotating tool plunged into the die and powders. From the X-ray CT and SEM observation of the pore structures of the fabricated Cu foam, it was found that almost the entire specimen had a pore structure similar to the NaCl morphology, regardless of the NaCl volume fraction. This is mainly because the sintering process for Cu particles in the FPC process was achieved at a temperature lower than the melting point of NaCl. From compression tests of the fabricated Cu foam, Cu foam exhibited ductile fracture regardless of its NaCl volume fraction, which is considered to be attributed to the good bonding between Cu particles. The plateau stress and energy absorption decreased with increasing NaCl volume fraction, indicating strong relationships between them. The Cu foam with the highest energy absorption per unit volume up to the specific stress changed from the high-NaCl-volume-fraction Cu foam to the low-NaCl-volume-fraction Cu foam with increasing compression stress. Consequently, it was shown that the mechanical properties of Cu foam can be controlled by adjusting the volume fraction of NaCl.
10.1016-j.msea.2013.09.003	-1		The effect of severe plastic deformation on the anisotropic strength change was investigated by equal-channel angular pressing (ECAP) experiments with various pass numbers. To overcome the size limitation for the tensile test specimen, this study proposes a shear punch test modified by using a flat-end rectangular punch to evaluate uniaxial tensile strength in multiple directions in the longitudinal and transverse sections of the ECAP-processed Cu-Cr-Zr alloy. The validity of the modified method was verified by the linear relationship between the shear punch test data and tensile test data in the longitudinal direction. Specimens were prepared at three angles (0 degrees, 45 degrees and 90 degrees) with respect to the extrusion direction in the longitudinal sections and the horizontal direction in the transverse sections of the ECAP bar. The results showed that tensile strength deceased when the angle increased from 0 degrees to 90 degrees in both the longitudinal and transverse sections. The longitudinal sections showed a more pronounced anisotropy than the transverse sections. As the amount of plastic deformation by ECAP increased, the degree of the anisotropy decreased in the longitudinal section but increased in the transverse section. Based on the results of this study, the strength of an ECAP material must be assessed in multiple directions in both the longitudinal and transverse sections.
10.1016-j.msea.2013.10.074	-1		Cu-1 wt% Al(2)0(3) nano-composites were prepared by three different methods, namely mechanical alloying, combustion synthesis and electrical explosion of wire, in order to investigate the effect of power processing technique on microstructure and ambient properties. The powders produced by these techniques were hydrogen reduced at 500 degrees C and subsequently vacuum encapsulated in copper container followed by consolidation using hot extrusion at 800 C and 600 MPa to nearly full density. As-synthesized composite powders as well as the extruded samples were characterized by scanning electron microscope, X-ray diffraction, transmission electron microscope, thermal conductivity and electrical conductivity. Microhardness and room temperature deformation behavior in compression at a strain rate of 10(-4) s(-1) were measured. The mechanically milled powders, upon consolidation, exhibited a finer grain size of 146 nm and a hardness of 164 HV1.0 compared to that obtained by two other techniques, which ranged between 179-390 nm and 135-156 HV1.0, respectively. The physical and mechanical properties were found to vary with grain size according to the Hall-Petch type relationship, irrespective of the processing technique employed for getting these grain sizes.
10.1016-j.msea.2013.11.079	6	grain; deformation; strain; strength; dislocation; cu-; tensile; size; ecap; grain size; sfe; ductility; hardening; high; stress	In ultrafine-grained (UFG) or nanocrystalline (NC) materials, achieving high strength often induces loss of ductility due to the formation of shear fracture without obvious necking feature. To investigate mechanical properties and fracture mechanism with reduced grain size, the macroscopic tensile fracture behaviors of UFG or NC Cu and Cu-Zn alloys were systematically investigated. It is found that the tensile strength and uniform elongation of UFG or NC Cu and Cu-Zn alloys display simultaneously increasing trend. The limitation of ductility can be attributed to the occurrence of shear bands in these materials; their main characteristic, the shear fracture angle, decreases with decreasing grain size as well as the degree of necking. The macroscopic fracture mechanisms are explained using an Ellipse criterion in terms of modification of the stress state in the fracture zone. It is suggested that the reduction of necking degree results from the geometrical hardening effect due to the change of the stress state. As the degree of necking decreases with decreasing grain size, the tensile shear fracture angle decreases too in the UFG/NC materials. Thus improving the geometrical hardening ability may effectively inhibit the formation of shear fracture, as the nucleation of shear bands becomes difficult.
10.1016-j.msea.2013.12.051	6	grain; deformation; strain; strength; dislocation; cu-; tensile; size; ecap; grain size; sfe; ductility; hardening; high; stress	Dynamic recrystallisation of CuAgZr alloys within a composition range of (3-7) wt% Ag and (0.05-0.3) wt% Zr is studied as a function of alloy composition, temperature and strain. Dynamic recrystallisation was investigated using hot-compression and hot-rolling experiments at temperatures between 500 degrees C and 850 degrees C. For CuAgZr with 7 wt%Ag and 0.05 wt% Zr, an optimised hot-rolling temperature of 750 degrees C was found and a mean grain size of 25 mu m was established at a true strain of 2.2. Similar grain size distributions were found for the extended range of alloy compositions while the active mechanism for dynamic recrystallisation changes from necklace towards a particle stimulated nucleation mechanism. This change is driven by the volume fraction of the ternary phase Cu4AgZr as these particles are identified to stimulate nucleation of dynamic recrystallisation in the samples with increased Zr content. The final tapes exhibit an outstanding combination of ultimate tensile strength of 1 GPa and an electrical conductivity of 70%IACS at a true strain of 4.8 of cold work being applied.
10.1016-j.msea.2013.12.071	-1		Mechanical tests of thermally aged Fe-Cu alloys were performed in the temperature range between 97 K and 297 K in order to investigate their low-temperature mechanical behavior. Tests performed below 122 K have shown that the material breaks in a random fashion already in the elastic region, while above it a clearly pronounced yield point is observed. This sudden change of the mechanical behavior has been rationalized on the basis of atomistic simulations, addressing the interaction of dislocations with Cu precipitates. The latter study has revealed the presence of bcc to fcc transition induced by dislocations which is a temperature dependent process. It is suppressed with increasing temperature and enhanced with increasing a precipitate size. This transition, efficient at low temperature, leads to the transformation of Cu precipitates into non-coherent particles, which act as stronger obstacles and cause the experimentally observed premature failure. The presence of small non-coherent Cu-precipitates, expected to form according to atomistic predictions, and not observed prior to deformation, was confirmed by means of transmission electron microscopy.
10.1016-j.msea.2014.02.028	4	transformation; martensite; martensitic; phase; shape; beta; memory; shape memory; temperature; temperatures; martensitic transformation; gamma; transformation temperatures; effect; thermal	The effects of grain size on the deformation under compression of a beta Cu-11.4A1-0.5Be (wt%) polycrystalline shape memory alloy were analyzed. As the maximum stress increases, major levels of pseudoelastic strain are obtained and the strain retained on unloading increases. The plot retained strain versus applied strain gives a unique curve that is independent of the grain size, with a pure pseudoelastic behavior up to around 3% of applied strain. The largest pseudoelastic strain possible to obtain increases as the grain size increases. Surpassed that strain, plastic deformation occurs and the macroscopic plastic stress follows a Hall-Petch type relation. In samples with plastic deformation the reverse martensitic transformation occurs in two stages, with a second high temperature calorimetric peak associated to the transformation of plastic deformed martensite.
10.1016-j.msea.2014.03.089	-1		Optimization of the surface structure and properties is of great concern since the failures of engineering materials such as wear, erosion and fatigue usually occur on the surface of materials. Plastic deformation from the sliding friction process has been utilized to realize surface nanocrystallization in commercial pure copper and tantalum plates in this work. The optical microscopy, transmission electron microscopy, X-ray photoelectron spectra, and uniaxial tensile testing results suggested that clean nanocrystalline surface layers of pure copper and tantalum were obtained, significantly strengthening the materials after the treatment.
10.1016-j.msea.2014.03.142	6	grain; deformation; strain; strength; dislocation; cu-; tensile; size; ecap; grain size; sfe; ductility; hardening; high; stress	In previous studies, the relationship between stacking fault energy (SFE) and the fatigue process has been examined under the fully reversed loading in which ratcheting does not occur. In this study, under the fully repeated loading, for pure Ni (128 mJ/m(2)), pure Cu (40 mJ/m(2)) and Cu-35 wt% Zn (11.5 mJ/m(2)) with different SFEs, the effect of fatigue damage and ratcheting damage on fatigue life was investigated. It was observed that for pure Ni, compared with pure Cu and Cu-35 wt% Zn, ratcheting damage is dominant. For Cu-35 wt% Zn, compared with pure Ni and pure Cu, fatigue damage is dominant. For pure Cu, both ratcheting damage and fatigue damage are dominant (mixed type). Thus, it was observed for the first time that high SFE tends to enhance ratcheting damage and low SFE tends to promote fatigue damage under the fully repeated loading.
10.1016-j.msea.2014.04.072	-1		In this paper, newly designed plastic Cu51Zr37Ti8Ni4 bulk metallic glass has been successfully fabricated. By purposely increasing the liquidus temperature in a quaternary Cu-Zr-Ti-Ni alloy system, glass-forming ability of as-cast bulk metallic glasses shows a desired decrease trend. As-cast Cu51Zr37Ti8Ni4, which has a lower glass-forming ability and a higher liquidus temperature than Cu52Zr37Ti8Ni3, is of monolithic amorphous structure, and also displays remarkable plasticity of 10.5% together with the fracture strength of 2145 MPa. Multiple and interactive shear bands can be discovered on the fracture surface of fractured Cu51Zr37Ti8Ni4. In addition, the deformation of Cu51Zr37Ti8Ni4 shows serrated flow behavior. By a statistics analysis of serrations in the stress-time curve, the serrated flow behavior of the sample follows the self-organized critical behavior. This work suggests that, with the aid of CALPHAD, composition design of plastic bulk metallic glasses can be achieved according to the liquidus perspective.
10.1016-j.msea.2014.04.101	-1		Edge cracks in Cu and Al single crystals under mode I loading conditions are investigated using molecular dynamics simulations. Calculations are carried out at 0 K and the embedded atom method potentials are adopted for (100)[011] edge crack systems. Five different crack lengths are employed to examine the effects of crack length on the fracture behavior of each material. The results show that Cu and Al exhibit different fracture mechanisms. The overall failure feature of Cu is brittle except for the shortest crack, for which the emission of dislocations preceded crack propagation. All the edge cracks in Al are extended through void nucleation and coalescence, and a zigzag fracture pattern is observed for each crack. Detailed analysis shows that the strikingly different fracture behavior of the two materials is the result of their different vacancy-formation energies and surface energies.
10.1016-j.msea.2014.05.018	4	transformation; martensite; martensitic; phase; shape; beta; memory; shape memory; temperature; temperatures; martensitic transformation; gamma; transformation temperatures; effect; thermal	Grain size has a strong effect on the pseudoelastic properties of shape-memory alloys. Different grain sizes and several related phenomena are studied. This involves the dependence of the transformation and retransformation stresses on grain size and on the amount of transformed material. A pronounced drop of transformation stresses on cycling is observed, until an asymptotic behavior is reached. This is related to the creation of defects (dislocations and dislocation arrays) and microplates of martensite, which are the defects necessary to allow the grains to accommodate due to the shape change imposed by the martensitic transformation. The asymptotic hysteresis is related to the internal work for the grains to accommodate each other once the necessary defects were created. The asymptotic hysteresis increases linearly as the grain size decreases. A simple model shows that the slope is related to the (d/e) ratio, where d is the average grain size and e is the width of the specimen. This effect arises from the presence of the free surfaces that release the plastic work for grain accommodation.
10.1016-j.msea.2014.05.093	6	grain; deformation; strain; strength; dislocation; cu-; tensile; size; ecap; grain size; sfe; ductility; hardening; high; stress	The strain rate sensitivity, activation volume and exhaustion of mobile dislocation density in nanocrystalline (NC) Cu-11.1 at%Al alloy with low stacking fault energy were studied by strain rate jump tests and repeated stress relaxations at room temperature. It was found that in comparison with NC Cu with similar grain size, the strain rate sensitivity of NC Cu-Al alloys is much small, which might due to the low SFE and the tendency of chemical short range order formation during plastic deformation. The small physical activation volume (similar to 20b(3)) was determined, which could be ascribed to the dislocation processes mediated by grain boundaries, twin boundaries. Meanwhile, a lower exhaustion rate of mobile dislocation density was found, possibly due to the low stacking fault energy enhancing dislocation storage capability, the high densities of nanotwins preserving mobile dislocations and a lower dislocation velocity in concentrated alloys.
10.1016-j.msea.2014.07.010	-1		Athermal quasistatic simulation of shear deformation has been conducted for a realistic model Cu-Zr amorphous alloy to investigate characteristic features of elasticity and plasticity of the material. Significant reduction of the shear modulus by nonaffine atomic displacements and appreciable nonlinearity of elasticity have been observed. The fourth-order elastic constant in shear deformation and the ideal shear strength have been evaluated. Plastic deformation has been observed to start with isolated local shear transformations (LSTs) followed by collective LSTs leading to the formation of a shear band. Participation-ratio analysis (PRA) has demonstrated how the nonaffine displacement field converges as the system approaches the critical point of losing structural stability. PRA has also evaluated quantitatively the numbers of atoms participating in LSTs-the average number is about 30. Spatially anisotropic development of nascent shear band on a plane has been shown, attributable to anisotropic internal stress field induced by an LST. The evaluated stresses for the shear-band nucleation and for its propagation have indicated that the yielding in real materials is controlled by the shear-band propagation, as previously pointed out.
10.1016-j.msea.2014.07.091	-1		The hot workability of CW602N brass, containing 36.5% Zn and 2% Pb, was investigated in the present study by hot torsion tests carried out between 550 and 700 degrees C. A detailed analysis of the literature data was preliminarily aimed at developing a constitutive model able to describe the hot deformation of single-phase alpha-brasses. The model, based on the Garofalo sinh equation, gave excellent descriptions of the mechanical response of copper alloys containing Zn amounts ranging from 0% to 30%, but overestimated the strength of the CW602N at the highest temperature. The model was then combined with the law of mixtures, to take into account the presence of the soft beta-phase, that appears when the Zn content increases above 35%, as was indeed observed in the CW602N. Both the flow curves and the peak flow stress dependence on strain rate were successfully modeled by assuming that the microstructure was composed of hard alpha-grains and soft beta-grains, containing Zn amounts close to 36-37% and 42-44% respectively.
10.1016-j.msea.2014.08.078	-1		Tensile properties of an electric brush-plated nanocrystalline Cu with an average grain size of 59 nm were investigated at different strain rates. This nanocrystalline Cu exhibits an excellent combination of strength and ductility with its ultimate tensile strength increasing from 635 MPa to 1000 MPa and total elongation decreasing from 15.8% to 9.9% as strain rate increases from 10(-4) s(-1) to 1 s(-1). Analysis based on the characterization results of transmission electron microscopy (TEM), scanning electron microscopy (SEM) and general area detector diffraction detection system (GADDS) on the as-brush-plated and deformed NC specimens revealed that the excellent combination of strength and ductility arises from the enhanced dislocation strain hardening ability and the improved deformation accommodation role played by GB sliding.
10.1016-j.msea.2014.09.080	-1		In this paper, Cu40Zr44Ag8Al8 bulk metallic glass composites (BMGCs) consisting of various volume fraction of nanocrystals embedded in the amorphous matrix was synthesized by controlled annealing treatment of an as-cast BMGCs. The high temperature compression behaviors of the BMGCs were characterized in the supercooled liquid region. Results show that the flow stresses keep increasing after an initial decrease with extension of the annealing time. With annealing the values of activation volume V-act is determined to be increasing from 283.6216 angstrom(3) to 305.553 angstrom(3), suggesting that the jump of atoms is a cooperative process during the high-temperature deformation. Flow behavior of the BMGCs annealed for less than 8 min transform from Newtonian to non-Newtonian dependant on the stain rate and can be successively fitted by the visco-plasticity model. Fitting results indicate that deformation behaviors of these samples are governed by homogeneous flow of the amorphous matrix and indeed determined by the viscosities in the Newtonian flow stage. However, the BMGCs annealed for 8 min exhibit a non-Newtonian flow over the entire compression process and fail to be fitted by the visco-plasticity model. Micrographs of the sample reflect an impinged structure, indicating that high temperature deformation behavior of the BMGCs with high volume fractions of particles is indeed controlled by that of a backbone of particles. (C) 2014 Published by Elsevier B.V.
10.1016-j.msea.2014.11.052	-1		The microstructure of single phase copper alloys is altered by cold deformation. Depending on the processing parameters like temperature and intrinsic material parameters as stacking fault energy, the dominant deformation mechanism is different and the refinement of the microstructure bears other rates with respect to the deformation strain. The formation of deformation twins is activated at low homologous temperature or at low stacking fault energy. Both also lead to smaller grain sizes achieved at a certain deformation strain. Lowering the temperature only yields to a high efficiency in strain hardening with respect to room temperature deformation for intermediate stacking fault energies. The maximum efficiency is found to occur in the vicinity of the onset of deformation twinning at room temperature which was found for a stacking fault energy of 30 mJ/m(2). The thermal stability of the microstructure is assessed by means of in situ resistivity measurements. (C) 2014 Published by Elsevier B.V.
10.1016-j.msea.2014.11.085	-1		Plastic anisotropy of ultrafine-grained (UFG) Cu-30%Zn tubes fabricated by parallel tubular channel angular pressing (PTCAP) process was investigated. The results showed that there was a severe anisotropy in UFG tubes in comparison with course grained counterparts. The PTCAP processed tube showed a very high strength of about 1220 MPa along the peripheral direction while it is about 580 MPa along the axial direction. Ultimate strength increased about 66% and 106% along the axial and peripheral directions, respectively. Comparison between the yield strength of CG and UFG tubes shows that the yield strength increases from similar to 106 MPa to similar to 344 MPa along the axial direction and similar to 359-1013 MPa along the peripheral direction. In the other word, the yield strength increases about 224% and 182% along the axial and peripheral directions, respectively. The hardness in the peripheral direction was almost greater than that in the axial direction which is in a good agreement with anisotropy of tensile properties. The corresponding textures verified this severe anisotropic in mechanical properties. The {111} plane was rotated about 90 with reorientation toward the radial direction after PTCAP processing while it is almost dispersal with a small texture to the extrusion direction in the annealed sample.
10.1016-j.msea.2014.12.041	-1		High pressure torsion is known as one of the most popular severe plastic deformation processes. However, it has certain size limitations, especially regarding the thickness of the processed samples. In this contribution incremental high pressure torsion is introduced as a novel severe plastic deformation process. This further development of conventional high pressure torsion is capable of delivering specimens having an extraordinarily high aspect-ratio of thickness to diameter. The features of this process combined with a case-study on a pure copper specimen with a deformed diameter of 50 mm and a thickness of 40 mm is presented. (C) 2014 The Author. Published by Elsevier B.V.
10.1016-j.msea.2014.12.070	-1		This paper describes the effects of gradient structure on mechanical properties of Cu-Zn alloys processed by surface mechanical attrition treatment (SMAT) at liquid nitrogen temperature (77 K). This method leads to the formation of a gradient structure with surface fine-grained regions and a coarse-grained interior. In this study, a fine-grained surface layer with a thickness of 10 mu m is formed on a coarse-grained Cu-Zn alloy sheet after the cryogenic SMAT process. Microstructural observations and microhardness measurements demonstrate that a significant microstructure refinement in grain size and a gradient increase in hardness from the coarse-grained core to the top surface. Tensile tests at room temperature showed superior strength-ductility synergy for the SMAT sample.
10.1016-j.msea.2015.01.021	6	grain; deformation; strain; strength; dislocation; cu-; tensile; size; ecap; grain size; sfe; ductility; hardening; high; stress	Samples of electrolytic tough pitch (ETP) pure copper were subjected to 12 passes of Equal-Channel Angular Pressing (ECAP) at room temperature with and without back pressure. Subsequent annealing was performed to evaluate the influence of back pressure during ECAP on the thermal behavior of ultrafine-grained copper. The microstructural and hardness changes caused by annealing were characterized by orientation imaging microscopy (OIM) and microhardness measurements. The application of back pressure resulted in an earlier drop in hardness upon annealing, which is believed to be associated with a lower critical temperature for the initiation of recrystallization and a rapid coarsening of microstructure. Regardless of whether back pressure was applied or not, structure coarsening during short-time annealing of ECAP-processed copper was governed by discontinuous static recrystallization. This is seen as a result of microstructure heterogeneity. Analysis of recrystallization kinetics was carried out based on observations of the microstructure after annealing in terms of the Avrami equation. The magnitude of the apparent activation energies for recrystallization in the absence of back pressure and in the case of back pressure of 100 MPa was estimated to be similar to 99 kJ/mol and similar to 91 kJ/mol, respectively. The reasons for reduced activation energy in the case of processing with back pressure are discussed.
10.1016-j.msea.2015.01.065	6	grain; deformation; strain; strength; dislocation; cu-; tensile; size; ecap; grain size; sfe; ductility; hardening; high; stress	The ultrafine-grained microstructures, mechanical properties and electrical conductivity of a Cu-0.87% Cr-0.06%Zr alloy subjected to multiple equal channel angular pressing (ECAP) at temperatures of 473-673 K were investigated. The new ultrafine grains resulted from progressive increase in the misorientations of strain-induced low-angle boundaries during the multiple ECAP process. The development of ultrafine-grained microstructures is considered as a type of continuous dynamic recrystallization. The multiple ECAP process resulted in substantial strengthening of the alloy. The yield strength increased from 215 MPa in the original peak aged condition to 480 MPa and 535 MPa after eight ECAP passes at 673 K and 473 K, respectively. The strengthening was attributed to the grain refinement and high dislocation densities evolved by large strain deformation. Modified Hall-Petch analysis indicated that the contribution of dislocation strengthening to the overall increment of yield stress (YS) through ECAP was higher than that of grain size strengthening. The formation of ultrafine grains containing high dislocation density leads to a small reduction in electrical conductivity from 80 to 70% IACS.
10.1016-j.msea.2015.04.008	-1		In this work, the mechanical properties of copper-silver cold sprayed deposits were studied versus composition (Ag content), deposition parameters and heat treatment temperature and duration. Low oxygen content (< 150 ppm), low porosity level (< 0.1%) and low residual stress level (< 1 MPa) were reached for deposits leading to an ultimate tensile strength higher than 600 MPa with about 10% elongation at rupture. In addition, results show that the high mechanical properties, obtained through second phase precipitation and cold work effect, can also be finely tailored by an adequate composition choice (i.e. Ag content), and further heat treatments.
10.1016-j.msea.2015.05.028	-1		Reusable launch vehicles require main combustion chamber liner materials that can withstand elevated temperatures and high stresses without creeping. GRCop-84 (Cu-8 at% Cr-4 at% Nb) was developed to meet this need. The Cr2Nb precipitates formed in the alloy strengthen the Cu matrix by impeding dislocation motion and inhibiting grain growth . GRCop-84 has been produced in a variety of forms, each with a unique processing history. The creep properties of the various forms were compared, and results demonstrated that processing had a statistically significant, quantifiable effect upon the creep properties of GRCop-84. The differences in creep properties could largely be explained by texture, testing environment and scatter of the test results. Even with the statistical differences, GRCop-84 did not show grossly different creep results as a function of processing, indicating that any of the processing methods would be suitable for producing a rocket engine liner. Published by Elsevier B.V.
10.1016-j.msea.2015.06.016	6	grain; deformation; strain; strength; dislocation; cu-; tensile; size; ecap; grain size; sfe; ductility; hardening; high; stress	An ultra-high purity oxygen free high conductivity (OFHC) Cu was investigated to determine the evolution of microstructure and microhardness during processing by high-pressure torsion (HPT). Disks were processed at ambient temperature, the microstructures were observed at the center, mid-radius and near-edge positions and the Vickers microhardness was recorded along radial directions. At low strains, Sigma 3 twin boundaries are formed due to dynamic recrystallization before microstructural refinement and ultimately a stabilized ultrafine grain structure is formed in the near-edge position with an average grain size of similar to 280 nm after 10 turns. Measurements show the microhardness initially increases to similar to 150 HV at an equivalent strain of similar to 2, then falls to about similar to 80 HV during dynamic recrystallization up to a strain of similar to 8 and thereafter increases again to a saturated value of similar to 150 HV at strains above similar to 22. The delay in microstructure and microhardness homogeneity by dynamic recrystallization is attributed to the high purity of Cu that enhances dislocation mobility and causes dynamic softening during the early stages of straining.
10.1016-j.msea.2015.07.021	-1		Cu-0.5Cr-1.5TiB(2) composites prepared by different melting processes were investigated in the present study. The optimum reaction temperature for the dispersed distribution of TiB2 particles is 1300 degrees C and a higher temperature is not appropriate due to the high loss of solute elements. Holding time should be 10 min to make TiB2 particles exhibit a relatively homogeneous distribution in the matrix. An argon shield is necessary to ensure obtaining the desired chemistry. The typical TiB2 particles with equiaxed and symmetric morphology are observed in the matrix, while particles with irregular morphology are obtained when the growth process is inhibited by adjacent particles. After aging, the better mechanical properties are obtained by composite prepared at the optimum melting process. Strengthening is comprised of a dislocation pile-up mechanism of TiB2 particles, precipitation strengthening of Cr particles and strain strengthening. TiB2 particles slightly decrease the electrical conductivity, which indicates a minor contribution from interface scattering. The conductivity exhibits an obvious increase after aging because of the sharp decline of impurity scattering.
10.1016-j.msea.2015.10.037	-1		By combined martensitic transformation calculation based on phenomenological theory and in-situ tensile tests, it was demonstrated that the mechanical properties of polycrystalline Cu-Ni-Al alloys can be enhanced by changing the stress state and improving the strength of grain boundaries. The experimental results indicated that, compared with ordinary hot-rolled Cu-Al-Ni alloys, controlled grain growth by continuous unidirectional solidification can change the stress state of grain boundaries and restrain intergranular cracks caused by local stress concentration, thereby making a significant tensile strain increase of 21.3% and superelasticity strain increase of 15.2%. Minor addition of B can enhance the bonding strength of grain boundary and reduce the formation possibility of intergranular cracks, resulting in a maximum tensile strain and superelasticity strain increase to be 3.1% and 2.0% respectively. These results would provide a theoretical and experimental foundation for enhancing mechanical properties of polycrystalline Cu-Al-Ni alloys by grain boundary control.
10.1016-j.msea.2015.10.046	-1		Microstructure of the Cu-Cr-Zr-Ce alloy was investigated by high resolution transmission electron microscopy (HRTEM), along with micro-hardness and electrical conductivity measurements. The alloy hardness and electrical conductivity can reach 170 HV and 66% IACS, respectively, after 80% cold rolling and aging for 16 h at 300 degrees C. Under the same aging conditions, without cold rolling, the hardness is 90 HV and electrical conductivity is 44% IACS. Two kinds of Cr and Cu4Zr precipitates were identified by TEM characterization after aging at 400 degrees C for 8 h . HRTEM microstructure analysis shows the presence of chromium-rich particles after aging for 18 h at 300 degrees C. Precipitates with ordered fcc structure are coherent with the matrix. Most of the precipitates are club-shaped chromium-rich particles, around 10-15 nm in size. The phase transformation kinetics was determined during aging. This study explored optimized processing conditions of the Cu-Cr-Zr-Ce alloy.
10.1016-j.msea.2015.10.062	15	aging; strength; conductivity; electrical conductivity; electrical; mpa; treatment; strengthening; degrees; cu-; cold; precipitation; tensile strength; tensile; iacs	A combined aging process has been developed to improve the comprehensive properties of Cu-2.7Ti-0.15Mg-0.1Ce-0.1Zr alloy. This process involved pre-aging at an elevated temperature, cold rolling, and final aging at low temperature. The alloy treated by this process was found to have good electrical conductivity and super-high strength . As the alloy was solution treated at 850 degrees C for 2 h, aged at 450 degrees C for 8 h, then cold rolled with the reduction of 90%, followed by aging at 400 degrees C for 4 h, the hardness, tensile strength, yield strength, the elongation and electrical conductivity of the alloy were up to 340 HV, 1035 MPa, 982 MPa, 3.1% and 20.1% IACS respectively. TEM observation revealed that the modulated structure and ordered Cu4Ti phases with coherent relationship with the matrix appeared during the pre-aging process. Cold rolling led to the formation of dense dislocation wall due to the dynamic interactions among the dislocations and precipitates. During the second stage of aging, the nano-scale precipitates formed in the pre-aging and the newly formed precipitates could effectively pin the dislocations formed in the cold rolling, the polygonization of recovery and recrystallization process could be retarded effectively. Therefore, the conductivity was enhanced without sacrificing the strength of the alloy when the second stage of aging was prolonged.
10.1016-j.msea.2015.10.119	6	grain; deformation; strain; strength; dislocation; cu-; tensile; size; ecap; grain size; sfe; ductility; hardening; high; stress	Low temperature deformation results in a considerable refinement of the microstructure of polycrystalline copper by extensive deformation twinning in the case of cryogenic wire drawing. In order to improve the thermal stability of the obtained microstructure, we investigate the deformation of CuZr alloys with up to 0.21 at% (03 wt%) Zr by drawing in liquid nitrogen up to a true strain of 2.4. An ultimate tensile strength of 625 MPa in combination with an electrical conductivity of about 60%IACS was found for an initially solution annealed CuZr0.21 alloy. For an initially precipitation treated CuZr0.21, a slightly lower ultimate tensile strength of 600 MPa at about 86%IACS was observed in the as-deformed state. Deformation twinning could be identified in all investigated materials, leading to a refinement of the microstructure. Thermal stability of microstructure as well as electrical and mechanical properties can be significantly improved by the addition of Zr. For cryo-drawn copper the drop of hardness due to recovery and recrystallization occurs between 200 degrees C and 225 degrees C for an annealing duration of 30 min. Small recrystallized grains are already identified at 175 degrees C. In CuZr0.21, a stable microstructure is found up to 350 degrees C for the solution annealed material while small recrystallized grains are found already at 300 degrees C in the precipitation treated material. By annealing a homogenized and subsequently cryo-drawn CuZr0.21 at 350 degrees C for 30 min, ultimate tensile strength can be further increased up to 635 MPa while electrical conductivity is enhanced significantly to 70%IACS by partial precipitation of Cu5Zr. Dynamic resistivity measurements indicate that this heat treatment subsequent to cryo-drawing does not affect the thermal stability of the prepared material.
10.1016-j.msea.2015.11.067	6	grain; deformation; strain; strength; dislocation; cu-; tensile; size; ecap; grain size; sfe; ductility; hardening; high; stress	This study demonstrates how to increase the hardness, the mechanical strength, the ductility and the electrical conductivity of Cu-8 wt%Ag alloy by engineering the precipitation kinetics of Ag. Discontinuous and continuous precipitation phenomena were shown by differential scanning calorimetry (DSC) to correspond to two distinct exothermic reactions in this alloy. Activation energy was found to be 63.7 +/- 0.1 kJ/mol for discontinuous and 68.7 +/- 23 kJ/mol for continuous precipitation. At higher temperatures (475-580 degrees C), both continuous and discontinuous precipitation occurred, but at lower temperatures (410 degrees C), only discontinuous precipitation was observed. Because of higher density and very fine continuous precipitation, the microhardness and tensile strength of a sample aged at 475 degrees C was up to 22% higher than samples aged at other temperatures (e.g. 170 degrees C, 410 degrees C, 580 degrees C, and 680 degrees C). Optimized microstructure also enhances the ductility in addition to the tensile strength and the hardness. Because the formation of precipitation reduces Ag dissolved in Cu matrix, the electrical resistivity of aged samples began to decrease above 410 degrees C. The size, volume fraction, and spacing of continuous Ag precipitates apparently play important roles in maximization of total strength and electrical resistivity.
10.1016-j.msea.2015.11.073	-1		In nanocrystalline alloys, some microstructural factors are usually tied to grain interior composition, including grain size, grain boundary composition, and grain boundary width . Due to the coupling of these factors, it is challenging to reveal the individual effect of solid solution strengthening. In this paper, sputtered Cu-Ti alloy multilayered films were designed to isolate the effect of solid solution strengthening in nanocrystalline alloys. Two series of nano-multilayered films were synthesized consisting of different low-alloy-content crystalline layers (6-188 nm thick) and same high-alloy-content amorphous layers (similar to 5 nm thick). The columnar crystals in crystalline layers with two different compositions both have the same diameters. The comparison of the two series of multilayered films show that the increase of Ti content from 0.3 to 53 at% results in a constant hardness enhancement of 1.5 +/- 0.2 GPa, as the height of columnar crystals in diameter of 10 nm decreases from 188 nm to 6 nm. This indicates that the solid solution strengthening effect of nanocrystalline alloys is independent of grain size not only when the deformation behavior is dominated by intragranular dislocation mechanism as coarse-grained ones, but also, more importantly, when it becomes dominated by grain boundaries.
10.1016-j.msea.2015.12.064	-1		The co-deformation of face centered cubic-face centered cubic and face centered cubic-body centered cubic systems were investigated using the cold drawn Cu-6 wt% Fe-4 wt% Ag alloys. Ag and Fe precipitates were introduced in the Cu matrix simultaneously and bonded together. Ag precipitates were successfully refined to nanofibers after heavy cold drawing while the Fe precipitates are hardly deformed. In-situ tensile test was performed in transmission electron microscope to reveal the dynamic interaction between Cu dislocations and Fe precipitates. Cu dislocations bowed out and bypassed the Fe precipitates while some residual segments were pinned at the Cu/Fe interface. Few dislocation pileups were found around the Fe precipitates. The different flow stress and slip system between Fe nanoprecipitates and Cu matrix are main reason for the poor co-deformation capability. The co-deformation of face centered cubic-body centered cubic system should be scale dependent.
10.1016-j.msea.2016.01.021	-1		The combined effects of ultrafine-grained (UFG) microstructure and precipitation on the formability and biaxial deformation behavior of a Cu-Cr-Zr alloy were investigated. The UFG microstructure formation results in good formability with an Erichsen index (Ei) of 4.05 mm compared to that of peak-aged coarse grained (CG) alloy (3.95 mm). Aging heat treatments increase strength and formability of the UFG alloy simultaneously. Biaxial deformation behavior is found to be dependent on the strain hardenability. Excellent strain hardenability of the CG alloy brought about higher punch displacement within the membrane stretching regime. However, deformation localization with the early onset of necking is evident in the UFG alloy. Subsequent aging treatments decrease deformation localization behavior of UFG alloy with increasing aging durations. Results also show that both grain refinement and aging increased the punch load due to enhanced strength . A linear relationship is generated based on punch load vs. punch displacement curve slope to predict ultimate tensile strength (UTS) with high accuracy. It is concluded that synergetic effect of UFG microstructure formation and subsequent aging provides a simple and effective procedure to produce Cu-Cr-Zr alloy for applications where balance of strength and formability are needed.
10.1016-j.msea.2016.01.027	6	grain; deformation; strain; strength; dislocation; cu-; tensile; size; ecap; grain size; sfe; ductility; hardening; high; stress	High purity copper was processed by high-pressure torsion (HPT) at room temperature and then stored at room temperature for periods of up to 6 weeks to investigate the effect of self-annealing. Hardness measurements were recorded both at 48 h after HPT processing and after various storage times. The results show the occurrence of recovery near the edges of the discs after processing through 1/2 and I turn and this leads to a significant drop in the measured hardness values which is accompanied by microstructural evidence for abnormal grain growth . Conversely, there was no recovery, and therefore no hardness drops, after processing through 5 and 10 turns. X-ray line profile analysis was used to determine the crystallite sizes and dislocation densities at 1 h after HPT and after storage for different times. The results show a good thermal stability in high purity Cu after processing through more than 1 turn of HPT but care must be exercised in recording hardness measurements when processing through only fractional or very small numbers of turns.
10.1016-j.msea.2016.01.044	6	grain; deformation; strain; strength; dislocation; cu-; tensile; size; ecap; grain size; sfe; ductility; hardening; high; stress	Ultrafine grained (UFG) copper with an average grain size of 115 nm was micro-alloyed with silver (UFG CuAg) to analyze its effect on strain rate sensitivity. The materials were prepared by sintering Ag microalloyed-Cu ultrafine powder, using the spark plasma sintering (SPS) technique and after H-2 pre-annealing for oxide reduction. Mechanical tests show that UFG CuAg follows the law of behavior established for UFG Cu: m approximate to B(1-sigma(0)/sigma), relating the strain rate sensitivity m and the applied stress, sigma. In this relation, sigma(0) is a threshold grain size dependent stress and B is characterizing the grain boundaries diffusion properties. Main difference compared to pure UFG copper is a large value of the parameter B for UFG CuAg, indicating a dominant role of the grain boundaries structure and chemistry on the rheology of UFG metals.
10.1016-j.msea.2016.04.068	-1		This work evaluates potential of Cu-Bi alloys comprising high volume fraction of Bi for high temperature soldering application. Cu-Bi alloys with 20, 40 and 60 vol% Bi are processed using liquid phase sintering (LPS). Effects of various sintering parameters, such as sintering time, temperature and relative green density, are studied to establish experimental conditions for preparing Cu-Bi alloys with optimum microstructure. Compression tests at different temperatures, ranging from RT to 260 degrees C, and strain rates, ranging from 5x10(-4) to 1 x 10(-2) s(-1), are conducted to assess effects of temperature, strain rate and Bi content on the overall mechanical response of the material. The sintered density increases with increase in the green density and, with some exception, also with the sintering period and the sintering temperature. On the other hand, overall densification decreases with green density. Yield strength and strain-hardening exponent of Cu-Bi alloys decrease with increase in both the mechanical testing temperature and the volume fraction of Bi in the alloy. In addition, a set value of strain rate sensitivity can also be attained by optimizing the Bi content in Cu-Bi alloy and the test temperature. Microstructurally aware finite element analysis is performed to gain insights into deformation processes. Finally, a rationale for using Cu-Bi alloys as high temperature solders is presented.
10.1016-j.msea.2016.04.069	6	grain; deformation; strain; strength; dislocation; cu-; tensile; size; ecap; grain size; sfe; ductility; hardening; high; stress	The microstructure evolution behaviors and corresponding quantitative rules of polycrystalline pure Cu and Cu-Al alloys under cyclic push-pull loading with rather large strain amplitudes (Delta epsilon/2 = +/- 2%similar to +/- 9.5%) were systematically investigated. Besides common dislocation structures, deformation twins (DTs), shear bands (SBs) and ultra-fine grains (UFGs) were observed for the first time in fatigued specimens with certain composition and strain amplitude. Based on careful observation and brief classification, a distribution diagram of above microstructures at various Al contents and strain amplitudes was summarized. Then, three corresponding criteria were proposed by developing theoretical models of microstructure evolution, to provide critical distributions of dislocation structures, DTs and UFGs. The calculated results display good agreements with the experimental observations. Both the experimental results and the theoretical analyses indicate the existence of general rules that dominate the microstructure evolution behaviors under cyclic loading. The investigation of these rules is of great significance for the further achievements on both the fatigue mechanism and the life prediction.
10.1016-j.msea.2016.04.076	6	grain; deformation; strain; strength; dislocation; cu-; tensile; size; ecap; grain size; sfe; ductility; hardening; high; stress	During grain refinement, fatigue strength usually does not increase always simultaneously with tensile strength for a certain material. To optimize the fatigue strength of ultrafine-grained (UFG) materials, systematic studies were carried out on the high-cycle fatigue behaviors of UFG Cu and Cu-Zn alloys. It is found that as the grain size decreases, although the fatigue strength coefficient (sigma'(f)) rises synchronously with tensile strength, the fatigue strength exponent (b) decreases continuously, which suppresses the improvement of fatigue strength . Nevertheless, by proper alloying to increase the planarity of dislocation slip, both the two parameters can be improved simultaneously. The increase of sigma'(f) can be owing to the much refined grain size and that in b should be ascribed to the improved slip reversibility and deformation homogeneity. Therefore, the fatigue strength of the UFG materials can be optimized by coordinating the microstructural approach (grain refinement) and the chemical approach (alloying).
10.1016-j.msea.2016.05.035	-1		Effects of temperature and strain rate on the tensile properties of Cu-Cr-Zr-Ti alloy in annealed condition were investigated by varying the initial strain rates from 10(-4) s(-1) to 10(-1) s(-1) at RT, 300 degrees C, 450 degrees C, 600 degrees C and 700 degrees C. The yield strength (YS) and ultimate tensile strength (UTS) of the alloy increased with an increase in strain rate at RT and 300 degrees C, whereas at 450 degrees C, the material exhibited the highest YS and UTS at the lowest strain rate of 10-4 s(-1). At 600 degrees C, the YS and UTS of the alloy increased with an increase in strain rate and showed the highest YS compared to all the temperatures tested. The alloy showed serrated yielding at 300 degrees C and at an initial strain rate of 10(-4) s(-1) whereas at 450 degrees C, serrated yielding was observed at 10(-3) s(-1) and 10(-4) s(-1) strain rates. Microstructural observations showed the presence of creep cavities at 450 degrees C and strain rate of 10(-4) s(-1). The creep cavities were present at higher strain rates as the test temperature is increased. Fractography indicates that the fracture is predominantly dimple fracture at RT and 300 degrees C and intergranular cracks were observed at 600 degrees C and 700 degrees C.
10.1016-j.msea.2016.05.042	6	grain; deformation; strain; strength; dislocation; cu-; tensile; size; ecap; grain size; sfe; ductility; hardening; high; stress	In this work, ultrafine-grained (UFG) copper alloys dispersed with nanoscale TiC particles were produced by combination of mechanical milling and spark plasma sintering (SPS). Microstructure evolution during uniaxial compression to height reduction of 20-60% in the temperature range of 400-700 degrees C was investigated systematically. The stress-strain curves in all conditions were characterized by a fast increase in stress at initial stage and a subsequent yield drop. No obvious microstructure change was observed with increasing reduction ratio. There exhibited a tendency in grain size refinement with increasing strain rate even the change in grain size is slight. A slight grain growth was found with the compression temperature high up to 700 degrees C. The high temperature tensile tests results suggested that the yield stress showed a relatively weak dependence on strain rate with a strain rate sensitivity parameter of around 0.02, and a low degree of strain hardening was observed. In addition, the recrystallization behavior was found to be inhibited by the ultrafine grains and nanoscale TiC particles in starting microstructure, because the grain boundaries or junctions in initial structure act as the severe pinning points, limiting bowing, and the nanoscale TiC particles prevent the nuclei formation of recrystallization. The fracture morphologies occurred during the tensile test were closely related to the change in particles distribution from random to aligned distribution during the hot press deformation. Crown Copyright
10.1016-j.msea.2016.06.007	-1		A bulk ultrafine grained Cu-1.2 vol%NbC-7.1 vol%C nanocomposite was fabricated by combining high energy mechanical milling from a mixture of Cu, graphite and Nb powders with spark plasma sintering and hot extrusion of the milled powder. The microstructure of the ultrafine grained Cu matrix nano composite consisted of equiaxed ultrafine Cu grains, NbC nanoparticles mainly inside the Cu grains, and C particles along the Cu grain boundaries. The thermal stability of the microstructure of the ultrafine grained Cu matrix nanocomposite during 1 h isochronal annealing at temperatures ranging from 750 to 1050 C was investigated, and we found that the ultrafine grained microstructure of the Cu matrix exhibited excellent thermal stability. With annealing the extruded sample for 1 hat 1050 C (0.98T(m), where T-m is the melting point of Cu in Kelvin scale), the average Cu grain size just slightly increased from 126 to 157 nm, the NbC nanoparticles had an average size of about 8 nm, and the average size of the C particles increased significantly from 68 to 109 nm. The very high thermal stability of the microstructure of the ultrafine grained Cu matrix during annealing at the elevated temperature close to its melting point can be attributed to the suppression effect of both intragranular NbC nanoparticles and intergranular C particles on Cu grain growth . Based on this investigation, considerations to be made in selecting intragranular nanoparticles and intergranular particles for stabilizing the microstructures of nanocrystalline and ultrafine grained metals and achieving superior strength are proposed.
10.1016-j.msea.2016.06.081	11	glass; bulk; metallic; bulk metallic; gfa; bmg; glassy; metallic glass; ability; bulk metallic glass; amorphous; addition; crystallization; mm; glass-forming	In this study, the effect different amounts of Ag and Co have on thermal stability, phase formation and mechanical properties of the glass-forming alloys (Cu0.5Zr0.5)(95)-(x).-yAl5AgxCoy (2 <= x <= 5 and 0 <= y <= 2) and CU47.5-yZr47.5Al5COy (0 <= y <= 2) was investigated, respectively. The addition of Ag increases the glass forming ability (GFA) of the alloys by enhancing the stability of the undercooled melt and by simultaneously reducing the stability of the B2 CuZr high-temperature phase. Co instead, has the opposite effect. It leads to an increased thermal stability of the B2 phase, as well as a decreased stability of the under cooled melt and, consequently, lowers the GFA of the alloys. Moreover, a metastable big cube phase precipitates in some alloys stabilized by oxygen, which is introduced during casting. There is a strong interdependence between the phase formation and the tendency of the present alloys to vitrify. This correlation can be captured by the K-parameter (Song et al 2011 [11) calculated from the respective transformation temperatures. The plastic strain of the present ternary, quaternary and quinary alloys reflects the GFA as well: the higher the tendency to form a glass, the smaller the plastic strain. Once B2 crystals precipitate in the glass, the plasticity is enhanced significantly.
10.1016-j.msea.2016.07.014	6	grain; deformation; strain; strength; dislocation; cu-; tensile; size; ecap; grain size; sfe; ductility; hardening; high; stress	The hot isothermal deformation of dispersion hardened Cu-Cr-Nb alloy was studied by varying strain rate and temperature during compression testing. The compressive stress-strain curves showed oscillations in the flow stress typical of type A, type B and type C serrations which are typical of Portevin-Le Chatelier effect. The serrated flow was attributed to the pinning of mobile dislocations by Cr2Nb precipitates. The presence Cr2Nb precipitates was also found to affect the dynamic recrystallization process during hot isothermal hot deformation.
10.1016-j.msea.2016.07.021	-1		Cu-Ni-Si alloys are widely used for electrical applications owing to high strength and high electrical conductivity. In this work, the effects of Cr and Zr additions on microstructure and properties of Cu-Ni-Si alloys were investigated. The addition of Cr and Zr results in formation of Cr3Si and Ni2SiZr intermetallic compounds, respectively, thus increases the electrical conductivity of Cu-Ni-Si alloy and refines the microstructure. Microstructure analysis confirms the presence of delta-Ni2Si precipitates, which strengthens the alloy through Orowan mechanism. Alloying with Zr element deteriorates the mechanical property of Cu-Ni-Si alloy, whereas in the presence of Cr, to the contrary, the ultimate tensile strength is increased, whether Zr is incorporated or not. Moreover, the addition of Zr can decrease the stacking fault energy (SFE) and promote formation of deformation twins. The best integrated, performance is obtained through co-addition of Cr and Zr elements. The ultimate strength, elongation and electrical conductivity are 706 MPa, 9.5% and 48.2% IACS, respectively. The precipitation kinetics was discussed in terms of Avrami equation and the activation energy of Ni2Si precipitation was obtained. The calculated activation energies of precipitation are 105, 89, 115 and 111 kJ/mol for Cu-Ni-Si, Cu-Ni-Si-Zr, Cu-Ni-Si-Cr and Cu-Ni-Si-Cr-Zr alloy, respectively.
10.1016-j.msea.2016.07.063	-1		The aim of present investigation was to achieve different combination of strength and ductility in Cu-Cr-Zr-Ti alloy by multi-pass rolling in the temperature range of 500-800 degrees C. The hot rolled specimens were characterized for microstructure and mechanical properties by optical microscopy, transmission electron microscopy, and tensile testing. Specimens rolled in the aforementioned temperature range showed yield strength better than that of solution treated condition. Combination of high strength and good ductility was achieved by rolling at 500 degrees C with ultimate tensile strength, yield strength, and ductility of 349 MPa, 318 MPa, and 26% respectively. The superior strength achieved by rolling at 500 degrees C has been attributed to formation of fine chromium precipitates and high dislocation density.
10.1016-j.msea.2016.08.086	6	grain; deformation; strain; strength; dislocation; cu-; tensile; size; ecap; grain size; sfe; ductility; hardening; high; stress	Aim of the present study is to investigate mechanical properties and fracture mechanisms of low stacking fault energy ultrafine grained Cu-9.6 wt% Zn brass processed by multiaxial forging (MAF) at cryogenic temperature. The alloy was developed by metal mold casting followed by homogenized annealing at 800 degrees C for 4 h before cryoforging. The forging was carried out for 5, 9 and 12 cycles which are equivalent to cumulative strains of 3.0, 5.4 and 7.2, respectively. The brass deformed with a cumulative strain of 7.2 showed more than 9 times improvement in the yield strength (YS=680 MPa) compared to that of the homogenized annealed sample (70 MPa). However, the ductility decreased to a very low range after deforming to 12 cycles because of extreme work hardening at the cryogenic temperature due to suppression of dynamic recovery. Cryoforging followed by short-annealing (225-300 degrees C for 20 min) was found to be effective to enhance the ductility without much affecting its YS. Formation of ultrafine grains along with nanotwins (confirmed by TEM) results a simultaneous improvement in the YS and ductility in the cryoforged + short-annealed samples. Macroscopic tensile fracture mechanisms and fractography analysis were carried out for the cryoforged and cryoforged + short-annealed samples. The unified tensile fracture criterion (Ellipse criterion) in terms of modification of the stress state in the fracture zone suggested that reduction of necking angle is resulted from the geometrical hardening effect due to the change of stress state. As number of forging cycles increases, which correspondingly increases critical normal stress (sigma(o)) and shear stress (tau(o)), the tensile shear fracture angle decreases indicating in the increase of shear mode fracture. This is ascertained to the grain size refinement, which increases the hardness of the material. Fractography analysis also highly corroborated with the analysis of the unified tensile fracture criterion and %elongation. The dimple size as well as %elongation was found to gradually decrease with decrease in the shear fracture angle, which is equivalent to increase in the cumulative strain.
10.1016-j.msea.2016.09.041	-1		Thermal energy storage and surge protection materials store surplus heat energy and inhibit the increase in the temperature of materials in case of excess energy generation or surge. This study explores usage of Cu-Bi alloys comprising high volume fraction of Bi for energy storage and surge protection. Cu-Bi alloys, comprising 20, 40 and 60 vol% of Bi, are prepared using liquid phase sintering by heating a mixture of Cu and Bi powders above the melting temperature of Bi, T-m,T- Bi. Compression testing of Cu-Bi alloys is conducted at temperatures above and below T-m,T- Bi. It is observed that the flow stress, yield stress, stress exponent and strain hardening exponent drastically decrease above T-m,T- Bi: In addition, compression creep testing is performed for Cu-40 vol% Bi at temperatures above and below T-m,T- Bi. The experimental results establish that this alloy can sustain moderate level of stresses at temperatures above T-m,T- Bi for long periods. Moreover, differential scanning calorimetry is employed to evaluate the heat storage capacity of the alloy with different compositions and effect of cyclic heating and cooling on the heat storage capacity. It is observed that the heat storage capacity of Cu-Bi alloy remains almost constant for several melting solidification cycles. Finally, it is suggested that Cu-Bi alloy containing high volume fraction of Bi can be used for energy storage and thermal surge protection.
10.1016-j.msea.2016.10.034	-1		Stacking fault tetrahedron (SFT) is the most common type of vacancy clustered defects in fcc metals and alloys, and can play an important role in the mechanical properties of metallic materials. In this study, molecular dynamics (MD) simulations were carried out to investigate the incipience of plasticity and the underlying atomic mechanisms in copper single crystals with SFT. Different deformation mechanisms of SFT were reported due to the crystal orientations and loading directions (compression and tension). The results showed that the incipient plasticity in crystals with SFT resulted from the heterogeneous dislocation nucleation from SFT, so the stress required for plastic deformation was less than that needed for perfect single crystals. Three crystal orientations ([1 0 0], [1 1 0] and [1 1 1]) were specified in this study because they can represent most of the typical deformation mechanisms of SFT. MD simulations revealed that the structural transformation of SFT was frequent under the applied loading; a metastable SFT structure and the collapse of SET were usually observed. The structural transformation resulted in a different reduction of yield stress in compression and tension, and also caused a decreased or reversed compression/tension asymmetry. Compressive stress can result in the unfaulting of Frank loop in some crystal orientations. According to the elastic theory of dislocation, the process of unfaulting was closely related to the size of the dislocation loop and the stacking fault energy.
10.1016-j.msea.2016.10.064	6	grain; deformation; strain; strength; dislocation; cu-; tensile; size; ecap; grain size; sfe; ductility; hardening; high; stress	Uniaxial tensile tests were conducted to investigate the plastic deformation behavior and deformation microstructures of coarse-grained Cu-Ni alloys containing a wide range of Ni contents (5-20 at%), which possess higher stacking fault energies (SFE) than pure Cu. The mechanical testing results show that, with increasing Ni content, i.e., jointly increasing SFE and degree of short range clustering (SRC), the ultimate tensile strength increases, but the ductility keeps almost unchanged; meanwhile, there exists an obvious increasing stage (or bump) in the strain-hardening rate curves at around 3% engineering strain. Microstructural examinations demonstrate that dislocations are apt to slip on primary slip planes at the initial stage of deformation (e.g., 3% engineering strain) to form planar slip bands, indicating that the existence of SRCs in Cu-Ni alloys is beneficial to the promotion of planar slip, leading to the occurrence of a bump phenomenon in the strain-hardening rate curves. With increasing deformation amount to a certain degree, wavy slip becomes the major deformation mode under the joint influence of high SFE and diminution of SRCs, and the final deformation microstructures transform from dislocation cells and cell blocks into extended dislocation walls with increasing Ni content. Both the cell block structures and extended dislocation walls subdivide the coarse grains uniformly to disperse local strain concentration, thus enabling the Cu-Ni alloys to maintain a high ductility with an increased tensile strength with increasing Ni content. In a word, the plastic deformation behavior of Cu-Ni alloys is actually governed by the competitive influence of SRC and SFE.
10.1016-j.msea.2016.10.087	-1		Cu-1Cr-0.1Zr (wt%) alloy strips were fabricated by a two-stage cryorolling and an intermediate aging treatment. The microstructures, mechanical/electrical properties and precipitation behaviors of the alloy were investigated. The results show that a desired combination of the tensile strength (690.13 MPa) and electrical conductivity (67% IACS) were obtained after the primary 30% thickness reduction and intermediate aging at 450 degrees C for 2 h followed by a secondary 60% thickness reduction at the cryogenic temperature. The improved strength can be attributed to the interactions of twin boundaries strengthening, grain boundaries strengthening, precipitation strengthening and strain hardening. For the alloy manufactured by cryorolling and intermediate aging treatment, the twin/matrix lamellar thickness decreases 38% and 55% compared with the alloy manufactured by cryorolling and room temperature rolling, respectively. In particular, results from energy-dispersive spectroscopy (EDS) mapping show that a core-shell structure with the shell of Zr and the core of Cr appeared after the intermediately aging treatment.
10.1016-j.msea.2016.11.094	-1		Residual stress remaining after plastic deformation significantly affects the physical and chemical behaviors of materials. In this work, the residual stress distribution in Cu after single-pass equal-channel angular pressing (ECAP) was evaluated using neutron diffraction and the finite element method (FEM). The residual stress distributions simulated using the FEM are in good agreement with the experimental results measured using the neutron diffraction method. The workpiece had non-uniform distribution of residual stresses from bottom to top region of a rod specimen with circular cross-section. The axial residual stress in the top region of the workpiece was highly tensile; while it was only slightly tensile in the bottom region. On the other hand, the radial and hoop residual stresses were tensile in the bottom region, whereas they were compressive in the top region. Despite such non-uniformity of residual stresses, the middle region of the workpiece had relatively homogeneous tensile residual stresses. This investigation on the residual stress distribution in the ECAP-processed material provides a new window from which engineering problems in related with residual stress can be issued and solved.
10.1016-j.msea.2016.12.061	-1		Nanotwinned materials exhibit simultaneous ultrahigh strength and high ductility which is attributed to the interactions between dislocations and twin boundaries but the specific deformation mechanisms are rarely seen in experiments at the atomic level. Here we use large scale molecular dynamics simulations to explore this intricate interplay during the plastic deformation of nanotwinned Cu. We demonstrate that the dominant deformation mechanism transits dynamically from slip transfer to twin boundary migration to slip-twin interactions as the twin boundary orientation changes from horizontal to slant, and then to a vertical direction. Building on the fundamental physics of dislocation processes from computer simulations and combining the available experimental investigations, we unravel the underlying deformation mechanisms for nanotwinned Cu, incorporating all three distinct dislocation processes. Our results give insights into systematically engineering the nanoscale twins to fabricate nanotwinned metals or alloys that have high strength and considerable ductility.
10.1016-j.msea.2016.12.091	6	grain; deformation; strain; strength; dislocation; cu-; tensile; size; ecap; grain size; sfe; ductility; hardening; high; stress	Step-wise deformations are applied to pure copper along uniaxial direction or multiaxial directions in three conditions of speed and temperature: static and room temperature, dynamic and room temperature, or dynamic and low temperature. Through examinations of total 36 deformation stages, the influences of strain rate, temperature, and deformation direction on microstructural evolution and mechanical properties are investigated. According to the results, the deformation mechanism at extreme conditions (high strain rate and low temperature) changes from only dislocation slip to dislocation slip and deformation twinning. Although deformation-direction change has no significant effect on the final mechanical properties and total dislocation densities measured from X-ray diffraction results, the evolutions of grain-boundary misorientation and geometrically necessary dislocations (GND5) are clearly influenced. The trend of microstructural evolution, i.e. larger grain size and lower GND densities by multi-axial deformation than the uniaxial case, is reversed when twinning occurred. Based on the results, we suggest four evolution models: uniaxial or multi axial cases with dislocation slip, or with dislocation slip and deformation twining. Even if the homogenous and almost fully twinned microstructure producing improved mechanical strength was obtained by applying the extreme deformations, poor ductility of the processed specimen were observed.
10.1016-j.msea.2016.12.120	4	transformation; martensite; martensitic; phase; shape; beta; memory; shape memory; temperature; temperatures; martensitic transformation; gamma; transformation temperatures; effect; thermal	Low-frequency internal friction study has been conducted for a copper-manganese-rich alloy (Cu -60 at%, gamma Mn). The study used a forced torsion pendulum working in low-frequency scans at constant temperatures, damping experiments ranging between 40 Hz and 10(-4) Hz. The dependence on temperature was extended from room temperature to the spinodal curve frontier at 923 K. Phenomenological stages in anelastic relaxations of (Cu, gamma Mn) were evidenced. Three thermally activated relaxation peaks were assigned respectively to point defects (Zener relaxation), dislocation segments and dislocation walls.
10.1016-j.msea.2017.03.034	6	grain; deformation; strain; strength; dislocation; cu-; tensile; size; ecap; grain size; sfe; ductility; hardening; high; stress	Aim of the present study is to investigate mechanical properties and fracture toughness of low SFE ultrafine grained (UFG) Cu-4.5 wt%(1) Al alloy processed through multiaxial cryoforging followed by short-annealing. The homogenized annealed samples (800 degrees C, 4 h) were cryoforged for 5, 9 and 11 cycles. The 11-cycles cryoforged sample showed more than 10 times improvement in the yield strength (YS) (818 MPa) as compared to that of the homogenized annealed sample (76 MPa). However, the ductility decreased to 10.1% elonagtion due to suppression of dynamic recovery and recrystallization during cryoforging. Cryoforging followed by short annealing (225-300 degrees C for 20 min) was found to enhance the ductility without affecting its YS. Fracture toughness study has been carried out through analysis of apparent fracture toughness (K-Q) using linear elastic fracture mechanics, equivalent energy fracture toughness (K-ee) and J-integral values using elastic plastic fracture mechanics from 3-point bend test data. The improvement of the YS with significant ductility as well as fracture toughness is ascribed to the formation of ultrafine grains & rhombic blocks (due to the intersection of nanotwins close to 90 degrees), mutual crossing & misorientation of microshear bands and multisystem deformation twins. The low SFE of the alloy is found to play the pivotal role to develop such microstructural features.
10.1016-j.msea.2017.03.069	-1		Cupronickel alloys, reinforced by L1(2) precipitates, offer a high strength, corrosion resistant and anti-bio fouling material for marine engineering applications. These alloys exhibit complex precipitate nucleation and growth mechanisms that must be fully understood in order to optimise the mechanical properties. In this work, the microstructural characteristics of the Cu-Ni-Al based alloy, Hiduron (R) 130, have been assessed in the as-received condition and following 100-h thermal exposures at 500, 600, 700 and 900 degrees C and after a two-stage exposure at 900 degrees C for 100 h followed by 500 degrees C for 100 h . The L1(2) phase was observed to precipitate both discontinuously and continuously and its subsequent coarsening was characterised alongside measurements of the lattice misfit. The hardness of the alloy was found to decrease with increasing exposure temperature up to the L1(2) solvus and correlated with the evolution of the L1(2) precipitates, the alloy grain size and the fraction of the discontinuously formed L1(2) phase.
10.1016-j.msea.2017.03.075	-1		Isothermal low cycle fatigue (LCF) properties of Cu-Cr-Zr-Ti alloy were evaluated at different temperatures (300 degrees C, 450 degrees C and 600 degrees C) in high purity argon atmosphere. The cyclic stress response (CSR) was highly dependent on the test temperature. CSR at 300 degrees C showed primary hardening and secondary hardening at lower strain amplitudes from 0.25% to 0.8% and primary hardening followed by continuous softening at 1.2% strain amplitude. At 450 degrees C, the alloy exhibited a higher degree of primary hardening followed by saturation of stress. Transmission electron microscopic observations made on the samples tested upto different number of cycles indicate that precipitation of fine Cr precipitates was the main reason for the secondary hardening at 300 degrees C and extensive primary hardening at 450 degrees C. Even though precipitation was assisted by mechanical working during cycling, it is observed that the secondary hardening occurred almost at the same time irrespective of the strain amplitude used in the tests. At 450 degrees C and higher strain amplitudes, precipitates nucleated at the dislocations within a few initial cycles causing pinning of the dislocations thereby increasing the stress response. CSR at 600 degrees C showed continuous softening without any hardening. It is found that the precipitates nucleated during heating and soaking at the test temperature itself before the start of the strain cycling and coarsening of precipitates as well as loss of coherency with the matrix caused continuous softening at 600 degrees C. With an increase in test temperature, a reduction in fatigue life is observed and the life reduction is significant at higher strain amplitudes. Microstructural observations and fractographic studies indicated that cracks initiated predominantly at surface and propagated inward. Intergranular cracking was observed at higher strain amplitudes at all temperatures.
10.1016-j.msea.2017.03.089	6	grain; deformation; strain; strength; dislocation; cu-; tensile; size; ecap; grain size; sfe; ductility; hardening; high; stress	An attempt has been made to investigate the high cycles fatigue behavior of the ultrafine grained (UFG) low SFE Cu-Zn and Cu-Al alloys processed through cryorolling/cryoforging followed by short-annealing. The samples (CRed Cu-9.6% Zn, CFed Cu-9.6% Zn & Cu-4.5% Al, and CRed+short-annealed (225 degrees C) Cu-4.5% Al), which showed better combinations of YS, ductility and fracture toughness, have been selected to investigate their fatigue characteristics. High cycle fatigue strength of the UFG alloys was found to be consistent in accordance with the static mechanical properties of the corresponding sample. For example, the CFed Cu-4.5% Al alloy samples showed superior fatigue strength along with the best combination of YS, ductility and fracture toughness as compared to that of the other samples. The improved fatigue strength of the alloys has been discussed in the light of effect of low SFE, complex and unique microstructural constituents developed by cryodeformation and role of static mechanical properties of the corresponding sample. TEM analysis after fatigue tests and fractography analysis near to fracture zones corroborated well in explaining the improvement of fatigue life of the UFG alloys.
10.1016-j.msea.2017.04.004	-1		The anelastic spectra of Cu39.5Zr51Al9.5, Cu54Zr40Al6 and Cu-47.75Zr47.75Al4.5 bulk metallic glasses were obtained by Mechanical Spectroscopy Technique at different frequencies. Studies below room temperature show two principal mechanisms: one broad peak, similar to beta relaxation, and another sharp peak, similar to alpha relaxation. This observation suggests that the interaction between amorphous structure and mechanical waves demonstrates that beta' relaxation can be decomposed in two principal peaks, one due to the movement of flow units and another owing to the growth of molecular-like structures. The behaviour of hybridization among Al-Cu atoms tends to decrease the free space in the amorphous matrix, increasing internal friction. The mechanical excitation and interaction among nanostructures such as cluster type, supercluster and molecular-like structure, can lead to growth of microalloy which may give rise to the medium-range order structure as well as increasing the small nanocrystalline region scattered into the glassy structure. In addition, the effect of mechanical vibration and cryogenic temperature acting on the amorphous structure can promote interaction among nanostructures resulting in a barrier that tends to block the propagation of shear bands in the metallic glasses.
10.1016-j.msea.2017.04.034	-1		Usually immiscible Cu-Cr compounds in equilibrium condition were mechanically processed via high pressure torsion with large and controlled strains. A systematical investigation on 57 wt%Cu-43 wt%Cr was carried out to get insights into the microstructural evolution of Cu-Cr nanocomposites and their dissolution process, as well as to determine the solid solubility limit of Cu and Cr elements under severe deformation. Microstructural evolution was captured with grain refinement from micron-size down to less than 20 nm as the increase of strains. A strain-saturated state in 57 wt%Cu-43 wt%Cr bulk was achieved after 100 rotations deformation (effective strain 1360), with a stable grain size of 13.7 nm and invariable hardness of 480-495 HV. Fine scanning of X-ray diffraction and sub-nanometer scale measurements of energy-dispersive X-ray spectroscopy showed that 32 wt% Cu could be fully dissolved into Cr matrix, and conversely solubility of Cr in Cu was determined to be about 3 wt% after an enough amount of deformation. The phase fraction change associated with Cu dissolution into Cr matrix during continuous deformation was captured and accurately calculated, indicating a negative exponential phase change mode. A phenomenological intermixing mechanism based on the kinetic competition between external forcing mixing and thermal-diffusion induced decomposition was proposed, which was well accordant with the phase evolution observed from experimental results.
10.1016-j.msea.2017.04.085	-1		The effects of rolling and heat treatment on the microstructure and superelasticity of columnar-grained Cu71Al18Mn11 shape memory alloy were investigated in this paper. Two different rolling strategies were adopted: (i) multipass high-temperature rolling (HR); (ii) one-pass HR followed by several-pass cold rolling (HR+nCR). For the first rolling strategy, the results showed that columnar-grained microstructure was reserved after one pass HR at 800 degrees C with rolling reduction of above 80%, and recrystallization would occur if more HR processes were applied. The superelastic strain could reach 5.9% in multipass HR sample through microstructure control by annealing at 800 degrees C. For the second rolling strategy, after the first pass HR with the reduction of 80% and annealing at 550 C, the alloy could be cold rolled at room temperature with total reduction of 50-70%. The columnar-grained microstructure still existed in the cold-rolled alloy which consisted of two phases (i.e. beta(1)+ alpha). After recrystallization annealing, the HR + nCR alloy tend to form < 011 > texture along the rolling direction, which was helpful to obtain high superelasticity. Finally, the grain growth heat treatment was used to further improve the superelasticity of the cold-rolled alloy. After 2-3 times abnormal grain growth heat treatment, the grains of the alloy could grow up from several hundred micrometers to more than one centimeter in diameter; they still had strong < 011 > texture along the rolling direction, which enabled the superelastic strain of as high as about 7%.
10.1016-j.msea.2017.05.001	15	aging; strength; conductivity; electrical conductivity; electrical; mpa; treatment; strengthening; degrees; cu-; cold; precipitation; tensile strength; tensile; iacs	High strength and high electrically conductivity Cu-Ni-Si alloys are important candidate materials for extending the life of currently used elastic-conductor materials. Phase transformation behaviors and properties of a synthesized Cu-6.0Ni-1.0Si-0.5Al-0.15Mg-0.1Cr alloy were investigated systematically. After homogenized for 4 h at 940 degrees C, hot rolled by 80% at 850 degrees C, solution treated for 6 h at 970 degrees C, cold rolled by 50%, and annealed for 60 min at 450 degrees C, the studied alloy approached physical properties of 1097.5 MPa in tensile strength and 26.4%IACS in electrical conductivity. Transmission electron microscope observations showed that four precipitation phases including delta-Ni2Si, beta-Ni3Si, beta-NiAl, and gamma'-Ni3Al were formed in the studied alloy, which was subjected to different annealing temperatures. A detailed diagram for isothermal decompositions has been established. The high strength of the studied alloy was primarily attributed to the Orowan precipitation strengthening, and secondary attributed to the solid solution strengthening, the Hall-Petch type grain boundary strengthening, and the work hardening. Multi-precipitation phases of Ni2Si, gamma'-Ni3Al, beta-Ni3Si played significantly into the strengthening effects, and the low electron diffraction influence of Mg and Cr contributed to both solution strengthening and maintaining a high electrical conductivity. Multi-phase precipitation strengthening and using trace amount alloying elements for solution strengthening will be a new strategy to develop high strength and high electrical conductivity copper alloys.
10.1016-j.msea.2017.05.010	-1		Effects of precipitation and strain-induced martensitic transformation of Fe-C phases on the mechanical properties of Cu-Fe-C alloy were systematically studied. The results reveal that, the hardness and strengths of Cu-Fe-C alloy can be increased after cold rolling, and forming shear bands in the alloy matrix. However, compared with directly cold rolling, the hardness, strengths and elongation can be all increased much more after using the processing of cold rolling 80% + heat treatment at 400 degrees C for 60 min + cold rolling 75%, which results from the contribution of both work hardening and precipitation strengthening of nano-sized alpha-Fe particles formed by strain-induced martensitic transformation. The formed a-Fe particles satisfy the K-S orientation relationship with Cu matrix, i.e. (011)(alpha-Fe)//(- 111)(Cu),[- 11-1] (alpha-Fe)//[110](Cu). These findings provide inspiring using the martensitic transformation of Fe-C phases to improve mechanical properties of Cu-Fe-C alloys.
10.1016-j.msea.2017.05.114	15	aging; strength; conductivity; electrical conductivity; electrical; mpa; treatment; strengthening; degrees; cu-; cold; precipitation; tensile strength; tensile; iacs	The effects of rolling deformation, rolling temperature and aging treatment on microstructure and mechanical properties of Cu-Cr-Zr alloy were investigated and the relevant influencing mechanism was also discussed in this study. The results showed that the tensile strength of the Cu-Cr-Zr alloy increased with an increase of rolling deformation at room temperature. The elongation to failure of the alloy decreased until the rolling reduction is up to 80% and then increased with the reduction, which is related to the grain orientation change from Copper texture with poor plasticity to the Goss/Brass texture with good plasticity. A large amount of Cr precipitates were identified during rolling at 300 degrees C in Cu-Cr-Zr alloy, which resulted in much higher electrical conductivity and tensile strength exceeded that of the room-temperature rolling with the rolling reduction over 80%. Aging treatment of 450 degrees C for 1 h led to the formation of massive Cr and Cu4Zr precipitates, which can significantly improve the tensile strength from 591.1 MPa to 669.1 MPa and electrical conductivity from 30.3%IACS to 74.5% IACS of the room-temperature rolled alloy. These results provide a guideline for exploring efficient preparation methods of high-performance Cu-Cr-Zr alloys.
10.1016-j.msea.2017.07.065	-1		The microstructure evolution of Cu-15Ni-8Sn-0.8Nb alloy during prior cold deformation by rotary swaging (RS) and subsequent aging treatment was investigated. Electron back scattered diffraction (EBSD) results indicated that the deformed microstructure mainly consisted of refined and elongated grains. Discontinuous precipitates appeared at previous grain boundaries (PGBs) and shear bands after deformation of 45 pct reduction. Transmission electron microscope (TEM) studies revealed that the transformation kinetics of both DO22 ordered phases and discontinuous precipitates were significantly accelerated by prior deformation, and the transformation from DO22 to Ll(2) ordering was suppressed to a certain degree. The maximum yield strength of the specimens with 45 pct reduction reached to about 1230 MPa after aging treatment, but the corresponding ductility was poor due to the rapid growth of discontinuous precipitates.
10.1016-j.msea.2017.08.017	-1		Strain controlled thermomechanical fatigue (TMF) behavior of Cu-Cr-Zr-Ti alloy was studied in the temperature range of 375-525 degrees C in high purity argon atmosphere under both in-phase (IP) and out-of-phase (OP) loading. In the case of OP TMF tests, the material exhibited continuous hardening without any saturation of stress. On the other hand, it showed cyclic hardening for the first few cycles followed by saturation of stress in IP TMF tests. The material exhibited superior lives under OP TMF loading compared to that under IP TMF loading especially at lower strain amplitudes. This may be attributed to the fact that the material experienced peak tensile stress at lower temperatures in OP TMF tests, where the resistance to crack initiation is expected to be higher. Microstructural observations and fractographic studies indicated mixed mode of fracture involving Intergranular facets and transgranular cracking in both IP and OP TMF tests.
10.1016-j.msea.2017.08.055	6	grain; deformation; strain; strength; dislocation; cu-; tensile; size; ecap; grain size; sfe; ductility; hardening; high; stress	As-cast Cu-1.5Fe-0.5Co (wt%) alloy displays both high tensile strength of 307 MPa and elongation of 33%. In situ transmission electron microscopy was used to investigate crack propagation in the alloy, to analyze the origin of the good properties. At different deformation stages in thin Cu foils, the interactions of a propagating crack with iron-rich nanoparticles and growth twins are investigated. Crack-bridging processes via near-tip twinned bridges were identified. The multiple deformation mechanisms act synergistically to contribute to high strength and high ductility in the alloy.
10.1016-j.msea.2017.08.064	-1		In this study, in situ white X-ray microbeam diffraction experiments were conducted to investigate the microscopic deformation behavior of a Cu-Al-Mn superelastic alloy during tensile testing. Local deformation both at a grain scale and an intragranular scale was revealed by analyzing Laue spot streaking that occurred within a grain and in some grains with different orientations. The streaking measured within a grain under tensile load showed inhomogeneous behavior because of an inhomogeneous martensitic transformation. Moreover, the effect was dependent on grain orientation. In a grain with a high Schmid factor, a large dispersion in the 20 diffraction angle of Laue spots was observed due to significant Laue spot streaking, which can be attributed to that grain's favored martensitic transformation.
10.1016-j.msea.2017.09.072	-1		Effects of multiple trace alloying element Fe and Cr addition on the solid solution-treated Cu-4 wt% Ti alloys were studied with respect to microstructure and mechanical properties. It was elucidated that the addition of trace alloying elements results in the formation of intermetallic phase CuTi, lowering the titanium content of Cu solid solution phase, and refining the microstructure. The contributions of different strengthening mechanisms were calculated, which are in good agreement on experimental results. It turns out that the solute solution strengthening in Cu- Ti alloys plays a crucial role, even though the fine grain size and precipitation strengthening mechanism are contributed to the strength of Cu-Ti-Cr-Fe alloys. Therefore, the Cu-Ti-Cr-Fe alloys exhibits lower strength and higher elongation compared with Cu-4 wt% Ti alloys. However, Cu-Ti-Cr-Fe alloys show a great potential to balance the mechanical properties and electrical conductivity during aging treatment as the titanium content decreases in the Cu matrix, and the strength is higher than that of others in previous study.
10.1016-j.msea.2017.09.110	-1		For the purpose of fabricating materials with a good self-sharpening capacity, the tungsten fiber reinforced Cu-Zn matrix composite was successfully fabricated by the pressureless infiltration method, and the microstructure of the prepared composite was investigated. To investigate the anisotropic mechanical properties, the quasi static and the dynamic compressive deformation behaviors of the composite in different loading directions were investigated. The angles between the loading direction and the tungsten fiber orientation are 0, 45 and 90, respectively. The failure mechanisms of the composite loaded in different directions were investigated systematically. Finally, the self-sharpening capacity of the composite was investigated by a ballistic impact experiment, and the mechanism of the self-sharpening capacity was discussed.
10.1016-j.msea.2017.10.044	-1		This work focuses on the role of the microstructure on the creep behavior of thin copper-clad aluminum (CCA) wires. Creep tests were performed at 150 degrees C on hard drawn and annealed CCA and on pure metals. It is shown that the Cu-Al interface of CCA ensures a mechanical resistance leading to lower creep velocities than for metals. Creep mechanisms are driven by aluminum at lower stresses and copper for higher stresses, independently of the physical nature of the interface.
10.1016-j.msea.2017.11.052	-1		A preliminary study has shown that bulk metallic glasses of the CuZrAI type of large dimension may be manufactured from amorphous powders densified by a process of sintering such as spark plasma sintering (SPS). However, to remedy the lack of plasticity of these materials, the addition of ductile crystalline particles was carried out in the present study. The zirconium was chosen because its properties are close to those of the amorphous matrix. The same sintering parameters as those optimized for the metallic glass are also applicable for the production of the composite for the different zirconium volume fractions retained, respectively 5%, 10%, 20%, 30%, 40% and 50%. The materials obtained are dense. X-ray diffraction clearly indicates that only the amorphous matrix CuZrAl and the crystalline zirconium are present. Young's modulus as well as the elastic limit decrease only very slightly with the addition of crystalline particles. Decrease in hardness is more pronounced. On the other hand, the plastic deformation increases with the addition of zirconium, reaching about 4.9% for the alloy containing 50% zirconium. The analysis of the fracture surfaces clearly shows the role of the ductile crystalline particles, namely the deceleration of the shear bands. The influence of volume fraction and size of the crystalline particles and of matrix toughness is discussed from a mechanical point of view. Therefore, SPS is a solution to solve both the problem of size and low ductility of amorphous metal, since it is possible to control microstructure and so to control mechanical properties.
10.1016-j.msea.2017.11.060	-1		Nanocrystalline metals with grain sizes less than 100 nm have strengths exceeding those of coarse-grained and even alloyed metals [1,2]. A bulk nanocrystalline Cu-1%Nb alloy was synthesized by an in-situ consolidation mechanical alloying technique. The mechanical behavior of this alloy was investigated by hardness and tensile tests. The nanostructure was investigated by X-ray diffraction and transmission electron microscopy and the fracture surface by scanning electron microscopy. Electrical resistivity was measured using a four-point probe technique. The dilute additives of Nb and the processing conditions induced artifact-free bulk nanocrystalline materials that possess extraordinary high strength, good ductility, and high electrical conductivity.
10.1016-j.msea.2017.11.076	6	grain; deformation; strain; strength; dislocation; cu-; tensile; size; ecap; grain size; sfe; ductility; hardening; high; stress	The deformation-mode transition model was extended to predict wavy to planar-slip and subsequent twin-induced plasticity (TWIP) transitions in solid solution copper alloys. In the deformation-mode map, the stacking fault energy (gamma/G) vs. frictional-stress (2F(f)/G) curves for Cu-Al, Cu-Mn, and Cu-Zn, crossed the boundaries of wavy-slip to planar-slip and planar-slip to TWIP transitions, with an increase in the solute content. The critical solute content predicted for the transition from wavy-slip to planar-slip to TWIP, by the deformation-mode transition model, was in good agreement with observations for solid solution copper alloys. Excellent agreement between the predictions and experimental data in the literature suggested that TWIP in Cu alloys is enhanced not only by the low stacking fault energy, but also by the frictional-stress on twinning partial-dislocations.
10.1016-j.msea.2017.11.083	6	grain; deformation; strain; strength; dislocation; cu-; tensile; size; ecap; grain size; sfe; ductility; hardening; high; stress	An ultrafine grained Cu with a wide distribution of grain size and an average grain size of d= 110 nm was prepared by electric brush-plating technique. Tensile properties, microstructure and deformation surface morphologies of this ultrafine grained Cu were compared with two results on an electric brush-plated nano crystalline Cu (d= 59 nm) and an electrodeposited ultrafine grained Cu (d= 200 nm) previously prepared by our group. Based on these comparisons, the strain rate dependences of strength and ductility of these three materials and underlying mechanisms were studied. It was revealed that the pronounced strain rate sensitivity (larger m value) of these three materials is a result of the competition between the dislocation and grain boundary mediated deformations. The grain boundary mediated deformation plays a very important role in controlling the tensile ductility of these three materials, which affects the deformation accommodation by promoting different modes of strain localization and hence leads to the completely different strain rate dependences of tensile ductility (the elongations decrease, remains unchangeable and increase with increasing strain rate).
10.1016-j.msea.2017.11.105	-1		The effects of minor additions (0.2, 0.4 and 0.8 wt%) of Ti on the thermal stability of both Cu nanograins and Y2O3 particles in nanostructured Cu-5 vol%Y2O3 composite powder particles were investigated via 1 h isochronal annealing at temperatures ranging from 300 to 1000 degrees C. It was found that a small amount addition of 0.4 wt%Ti effectively inhibits the coarsening of the Y2O3 particles during annealing at a very high homologous temperature of 0.87T(m), where T-m. is the melting point of Cu, which, in turn, stabilizes Cu nanograins and retains the hardness value of the as-milled powder sample. However, this is in clear contrast with the significant decrease in hardness of the Ti-free and 0.2 wt%Ti doped milled powder samples annealed at the same condition, resulting from the coarsening of the Y2O3 particles and growth of Cu nanograins. The energy dispersive X-ray spectrometry elemental analysis shows that the stabilizing mechanisms responsible for the improved thermal stability of the Y2O3 particles are associated with the chemical reactions between Ti, O and Y2O3.
10.1016-j.msea.2017.11.116	-1		Bulk ultrafine grained Cu-0.8 wt%C alloy samples were fabricated by spark plasma sintering (SPS) of a nano crystalline Cu-0.8 wt%C alloy powder prepared by high energy mechanical milling. The SPS temperature was 800 degrees C. The SPSed samples exhibited a bimodal microstructure consisting of ultrafine and coarse Cu grains (average grain sizes: similar to 95 nm and similar to 1 mu m respectively) and a yield strength of 483 MPa, but underwent a premature fracture at a stress of 511 MPa with a low elongation to fracture of only 0.3%. It is established that the premature fracture and low tensile ductility are caused by the high flow stress associated with grain boundary strengthening and reaching the strength of IPBs before reaching its maximum. Hot extrusion of the SPSed sample at 800 degrees C caused substantial growth of the ultrafine Cu grains and enhancement of the strength of IPBs, leading to a clearly lower tensile yield strength of 353 MPa, but mature fracture with an ultimate tensile strength of 428 MPa and a significantly improved elongation to fracture of 6.5%.
10.1016-j.msea.2018.01.014	-1		In the present study, commercial Cu-35Zn alpha-brass sheets were subjected to cryogenic rolling (CR) to obtain samples with different amounts of deformation in the thickness direction. A self-designed liquid nitrogen cooling system that can simultaneously cool the work rollers and samples was used to ensure an ultra-low temperature condition during the rolling process. The grains, deformation twins, and dislocation density of the samples were studied by optical microscopy, transmission electron microscopy (TEM), and X-ray diffraction (XRD). Uniaxial tensile tests and Vickers hardness measurements were conducted to measure the mechanical properties of the samples. The microstructures and mechanical properties of CR samples were apparently improved compared to the room temperature rolling (RTR) samples with increasing deformation amount. As a typical example, when the deformation amount is 90%, the CR sample possesses ultrafine microstructures and demonstrates extraordinary mechanical properties. The average tensile and yield strengths of a 90% deformation CR sample can be improved to 835.3 MPa and 711.5 MPa, while those of a 90% deformation RTR sample are 718.6 MPa and 481.2 MPa. The average elongation of the CR sample is 2.9%, which is acceptable compared with the RTR sample whose average elongation is 3.1%. The ultrafine microstructures containing ultrafine grains, high density dislocation, and nanometer scale deformation twins in the 90% deformation CR sample may be the main reason for its extraordinary mechanical properties. Therefore, samples with a good combination of strength and ductility were obtained in the present study. This may be a valuable exploration to fabricate Cu-35Zn alloy sheets with excellent microstructures and mechanical properties.
10.1016-j.msea.2018.01.022	-1		The effects of Nb addition on the microstructures and mechanical properties of the casting Cu-9Ni-6Sn alloy were investigated in the present work. Microstructures of the as-cast and heat treated samples were characterized by optical microscopy (OM), scanning electron microscopy (SEM) and transmission electron microscopy (TEM). The results demonstrate that, with the addition of Nb from 0.0 wt% to 0.35 wt%, the average grain size of Cu-9Ni-6Sn alloys in the as-cast condition is reduced from 570 mu m to 156 mu m due to the formation of Nb-bearing intermetallic compounds. The occurrence of NbNi3 particles after solution treatment is considered as an important factor that leads to the postponed hardening response to age treatment in the early stage. For the peak-aged samples with 0.35 wt% Nb addition, the tensile strength is increased from 768.9 to 913.3 MPa when compared to that of the Nb-free samples. In addition, for the peak-aged samples, the hardness increment is mainly attributed to the coherent stress generated by the ordered gamma' phases, which results in practically identical hardness (similar to 350 HV) regardless of the Nb additions. Furthermore, an optimized combination of UTS (719.5 MPa), elongation (13.76%) and electrical conductivity (11.37% IACS) of the Cu-9Ni-6Sn alloy can be achieved by the 0.35 wt% Nb addition accompanied with aging treatment at 375 degrees C for 1 h .
10.1016-j.msea.2018.02.046	-1		The dynamic mechanical relaxation of metallic glasses is closely associated with the physical and mechanical properties. In the current work, the dynamic mechanical relaxation behaviors of Cu46Zr45Al7Y2 and La65Al14(Cu5/6Ag1/6)(11)(Ni1/2Co1/2)(10) bulk metallic glasses are investigated by mechanical spectroscopy. In general, metallic glasses display two relaxation modes: main (alpha) relaxation and the slow secondary (beta) relaxation. The a relaxation is linked to the dynamic glass transition phenomenon and viscous flow while the slow beta relaxation is associated with many fundamental issues, such as diffusion and glass transition phenomenon. The experimental study shows La65Al14(Cu5/6Ag1/6)(11)(Ni1/2Co1/2)(10) bulk metallic glass displays a noticeable slow beta relaxation. Contrarily, the Cu46Zr45Al7Y2 bulk metallic glass relaxation process takes the form of an excess wing. In the framework of quasi-point defects (QPD) theory, the dynamic mechanical response of the metallic glasses is discussed.
10.1016-j.msea.2018.02.051	-1		Selective laser melting (SLM), as a novel additive manufacturing technique, has attracted increasing attention in copper alloys. In this research, to investigate forming processing and attendant mechanical properties of high-tin bronze in SLM, a statistical relationship between processing parameters (laser power, scanning speed and hatch space) and density of Cu-15Sn bronze in SLM was established using an experimental approach with response surface method and analysis of variance. As such, nearly fully-dense SLM Cu-15Sn bronze specimens were firstly manufactured whose reasonable microstructural evolution and mechanical properties were investigated before and after annealing and compared with QSn15-1-1. (GB/T 5231-2012) drawing specimens. It is found that the SLM Cu-15Sn specimens present the significantly fine grain microstructures that consist of cellular and dendritic structures. The ultimate tensile strength varies from similar to 661 MPa to similar to 545 MPa, the elongation at break from 7.4% to > 20% and the Vickers hardness ranges from similar to 212 HV 0.3 to similar to 168 HV 0.3 for SLM Cu-15Sn specimens after annealing, which are generally superior to those of QSn15-1-1 specimens. In addition, it has been proposed that the dominated strengthening mechanism of SLM Cu-15Sn parts has transformed from fine-grain to solid solution strengthening after annealing.
10.1016-j.msea.2018.03.026	-1		In this paper, a new high strength copper based alloy (Cu-20 at%Fe-5 at% Si) in Cu-Fe-Si system is reported that is designed by accessing submerged liquid miscibility gap of the Cu-Fe system and ternary addition of Si for a hierarchical design of microstructure. The alloy was synthesized by suction casting of the melt into a copper mould. This paper further elucidates the sequence of evolution of metastable phases in the microstructure due to non-equilibrium solidification through detailed characterizations of the microstructure of the alloy using transmission electron microscopy. The microstructure containing particles with globular morphology of the Fe rich DO3 ordered phase suggests its origin in the liquid state consistent with the expectation of a metastable liquid immiscibility. The solute rejection process during the later stage of solidification and the solid state cooling results in the evolution of Fe rich nano sized fully coherent ordered particles in the Cu-rich matrix. This particular alloy has achieved an excellent mechanical strength both at room temperature and at elevated temperature. The correlations between microstructure and mechanical behavior have been discussed in details.
10.1016-j.msea.2018.04.018	-1		Experiments were conducted to study the compression behavior of Cu-Ni foams prepared using freeze casting. The struts of the foam samples were solid-solutioned with differing Cu/Ni ratios, after which the grain size in the struts was measured using scanning electron microscopy. The compression performance of the samples was studied in both parallel and perpendicular directions to the temperature gradient, and compared with model calculations. It was confirmed that alloying increased the yield strength of the struts. The experimentally determined yield strength and elastic modulus were compared with model calculations, which revealed that the elastic modulus of the foams was lower than the values calculated from the classical compression and Gibson-Ashby models due to variation in the thickness of the struts. It was also found that the alloying of Cu and Ni improved the mechanical performance of the alloy foams because the absorbed energy for the alloys was considerably higher than that for the pure foams.
10.1016-j.msea.2018.04.023	-1		Mechanical indentation tests have been long and continuously investigated to be used as an indirect method to evaluate the elasto-plastic behavior of materials. It is well known that mechanical properties of some materials are sensitive to strain rate and yet few works have been done on the study of mechanical indentation of materials at different velocities. A procedure to evaluate the strain rate sensitivity of metallic materials from mechanical indentation tests performed at different velocities is here explored. Mechanical indentation tests were carried out in mild steel, copper, titanium alloy and brass. The strain rate sensitivity of these materials were also obtained using conventional tests. The results obtained from indentation tests were compared against conventional tests plus literature data. It was concluded that mechanical indentation tests at different velocities is a promising technique to measure the strain rate sensitivity of metallic materials.
10.1016-j.msea.2018.04.077	15	aging; strength; conductivity; electrical conductivity; electrical; mpa; treatment; strengthening; degrees; cu-; cold; precipitation; tensile strength; tensile; iacs	Effect of Ag addition on the microstructure and mechanical properties of as-cast, cold-rolled and aging treated Cu-Cr alloys were investigated in this study. The results indicated that adding a small amount of Ag significantly improve the mechanical properties of the Cu-Cr alloys with little effect on electrical conductivity. Besides the solution strengthening mechanism of Ag, the distribution changes of Cr precipitates from the chain along grain and dendritic boundaries to homogeneously dispersed sphere in the as-cast Cu-Cr-Ag alloys, and more fibrous Cr precipitates obtained in the cold-rolled Cu-Cr-Ag alloys also played key roles in the performance improvement of the alloys. By intermediate frequency induction melting with non-vacuum melting condition, 1000 degrees C-60 min solution treatment, 95% cold-rolling deformation, and 400 degrees C-90 min aging treatment, the Cu-0.89Cr-0.44Ag alloy exhibited excellent mechanical-electrical properties with the tensile strength of 541.5 MPa and electrical conductivity of 83.2%IACS. Meanwhile, the Cu-0.94Cr-0.11Ag alloy showed a better cost performance (tensile strength .conductivity/raw material price per kg) about 800 MPa.%IACS/Yuan. These relevant results provided important references for research and development of the high-performance Cu-Cr-Ag alloy.
10.1016-j.msea.2018.04.085	-1		In this work, 2 mm thick Cu-30Zn brass plates were successfully joined by using large-load and low-speed friction stir welding. Heat-affected zone was eliminated due to the significantly improved thermal cycle. The stir zone exhibited ultra-fine grains, with high fraction of twin boundaries and low dislocation density. Also, several nanoscale twin boundaries were introduced into the stir zone. Grain structure refinement in the weld was attributed to the combination of discontinuous, continuous, geometric and shear-band-assisted dynamic recrystallization mechanisms. Consequently, the stir zone showed excellent strength-ductility synergy compared to that of the severe plastic deformed and the conventional friction stir welded Cu-30Zn brass. A feasible one-step strategy was developed herein, to increase the strength of the friction stir welded Cu-30Zn brass joint, while avoiding ductility loss. Moreover, this study offers a new insight and choice for joining metals or alloys with higher melting points, such as steel and titanium alloys.
10.1016-j.msea.2018.05.008	6	grain; deformation; strain; strength; dislocation; cu-; tensile; size; ecap; grain size; sfe; ductility; hardening; high; stress	The surface strengthening behaviors of cold-rolled (CR) Cu, fully recrystallized (FR) Cu and partially recrystallized (PR) Cu with heterogeneous microstructures were investigated by using the surface spinning strengthening (3S) method. It was found that the heterogeneous microstructure significantly affects surface strengthening behaviors as the fine grains have good plastic deformation ability, the ultrafine grains can bear a high stress, and the whole hardened layer can be divided into grain refinement and deformation zones. The maximum microhardness is 173 HV across all Cu because all the grains were refined to the nano-scale with an average size of 40 nm in the topmost layer of the grain refinement zone. The fine grains in the deformation zone of the PR Cu deform plastically to generate a thick hardened layer. In addition, the surface strengthening behaviors and mechanisms are discussed in detail.
10.1016-j.msea.2018.05.035	-1		A series of Cu-W films with the W content higher than 17.2 at% were prepared by magnetron sputtering focused co-deposition technology. The micro-structures and nanoidentation hardness of the films were investigated. Except for the fcc, amorphous and bcc phases, a novel multilayered structure has been observed at the range of about 17.2-90 at% W. Within the multilayered structure, the high-density interfaces can inhibit the motion of dislocations, which resulted in the hardness at least 2 GPa higher than that of the mixing rule. Depending on different microstructures, the hardness curve of the Cu-W films can be divided into three regions instead of the linear increase with the W content. From 17.2-40 at% W, the hardness increased slowly due to lots of amorphous phase. Within 40-65 at% W, the hardness increased linearly, which was caused by the gradually obvious multilayered structure and decreasing amorphous content. Above 65 at% W, single-phase body-centered cubic (bcc) films were observed. In this region, the upward trend of hardness slowed down due to the porous columnar structure and gradually disappeared multilayered structure.
10.1016-j.msea.2018.05.050	-1		The effect of grain size and the ratio of specimen thickness to grain size on the deformation behaviors of Cu-3 wt%Ag-0.5 wt%Zr thin sheet is investigated by tensile test. For investigating the role of precipitates being generated by age process on the size effect of the thin samples, a constitutive equation is constructed by considering secondary phase hardening behavior and surface layer model. The results suggest that the critical feature value (grain size/thickness) of size effect is equal to 0.2-0.25 which is very similar to that of pure copper. However, because the precipitates strengthen role will weakness in the surface of specimen when there are only 4-5 grains across the specimen thickness, the size effect is presented more evident.
10.1016-j.msea.2018.05.082	-1		In this research, Tin was alloyed to the Cu(47)Zr(47)A(16) bulk metallic glass to induce chemical heterogeneities formation and study its effect on the mechanical and thermal properties. The large difference in enthalpy of mixing of Sn-Zr (- 43 kJ/mol) and Sn-Cu (+7 kJ/mol) causes chemical heterogeneities. Microstructural examination showed composition fluctuations including Cu-rich and Zr-rich zones in (Cu47Zr47Al6)(99) Sn-1 alloy, improves ductility and fracture strength by 72.15% and 26.37%, respectively. Correlation between microstructure and mechanical properties was investigated through work hardening behavior, serration density and fractography of compression samples. Chemical heterogeneities lead to increase in shear bands, consequently enhance ductility and work hardening rate.
10.1016-j.msea.2018.05.090	-1		Experiments were performed to investigate the tensile deformation characteristics of a Cu-2.5 wt% Ni-0.55 wt% Si alloy containing trace elements of Zn, Sn and Mg, processed by high-pressure torsion (HPT) under an applied pressure of 5 GPa for 10 revolutions, and then peak-aged or over-aged at 300 degrees C. The grain size of the HPT-processed (H) alloy was refined to 70 nm. The peak-aged (PA) alloy exhibited a higher tensile strength sigma(u) of over 1 GPa than the H alloy. The over-aged (OA) alloy exhibited a lower value of sigma(u) than not only the PA but the H alloy. The PA and the OA alloy revealed unique tensile deformation properties: an extremely small local elongation of 0.1% for the PA alloy, a very small uniform elongation of 0.2% for the OA alloy, and a sudden drop of tensile stress immediately after necking initiation for the OA alloy. The small local and uniform elongation for the PA and OA alloy were explained on the basis of intergranular fracture after and before necking initiation during tension. The stress drop was caused by the rapid propagation of intergranular fracture from the surface of necking part to the interior. Intergranular segregation of Sn promoted by aging at 300 degrees C resulted in the intergranular fracture of the PA and OA alloy.
10.1016-j.msea.2018.06.010	-1		Introducing coarse grains into nanocrystalline (NC) and ultrafine grained (UFG) metallic materials can lead to an excellent combination of strength and ductility. In this study, we produced Al2O3 dispersion-strengthened (Al2O3-DS) Cu with heterogeneous microstructure by mechanical alloying (MA) of Cu-Al2O3 powder mixture followed by spark plasma sintering (SPS) and hot extrusion (HE). For direct comparison, one sample was prepared by hot extrusion only without prior SPS of mechanically alloyed (MAed) powders. The microstructure of materials produced via a combination of SPS and HE possessed the heterogeneous microstructure consisting of Al2O3-free coarse grained (CG) Cu bands and Al2O3-rich UFG Cu regions. These different microstructural regions were found to play different roles on the tensile and electrical properties and their presence can be tuned to achieve desired mechanical and electrical properties. We also discuss the possible mechanisms responsible for the formation of the heterogeneous microstructure in the samples produced by a combined process of SPS and HE.
10.1016-j.msea.2018.06.013	-1		The porous Cu-Sn-Ti composites were fabricated by using a sintering-dissolution process with carbamide particles as space holders. The macroporosity of the composites was consistently controlled. The micropores among the pore-walls and wall intersections were quantitatively analyzed by using 2D micrographs and 3D X-ray tomographic reconstruction technique. The size, shape and distribution of the micropores and their effect on the mechanical properties of the composites (compressive strength, Young's modulus, and flexural strength) were investigated in relation to the composite formation mechanism and micropores evolution. It was found that the amount of graphite particles has a significant impact on the micropores formation and further on the mechanical properties of the bulk material. The rapid increase in the number of micropores as well as the gradual decrease in the compressive and flexural strengths were found to be caused by the increase of the graphite particle concentration. The mechanical performance could be improved by optimizing the alloy composition content and arranging the distribution of carbamide particles.
10.1016-j.msea.2018.06.075	-1		A commercial Cu-Ni-Si-Cr alloy used as a model material was annealed and then peak-aged. The detailed microstructure and property analyses were performed to determine the correlations between the microstructure characteristics and properties. Theoretical calculations, which gave results in good agreement with experimental results, demonstrated that solid-solution scattering and Orowan bypass of precipitate strengthening were the key mechanisms for electrical and mechanical properties, respectively. Furthermore, the effects of composition on the aging behaviors and then electrical and mechanical properties for Cu-Ni-Si series alloys were systematically investigated, showing that both the precipitation extent and mechanical properties improved simultaneously with nominal or effective concentration of the precipitates. Quick estimation on the basis of the present analysis procedure indicates that our work is applicable with high accuracy in real cases.
10.1016-j.msea.2018.09.064	-1		In the present study, the influence of rare earth element gadolinium (Gd) on Cu-Al-Be polycrystalline shape memory alloy has been investigated. Cu (88.13) Al 11.42 Be (0.45) ternary alloy with addition of Gd from 0.05 to 0.15 wt% has been used for investigation. The tests have been carried out for microstructure, morphology, ductility, phases, crystal structure, phase transformation temperatures and shape recovery ratio. Refinement of the grain size resulted as gadolinium increased from 0 to 0.08 wt%, the grain size decreases from 463.45 to 81.80 mu m with reduction of 82.34%. The tensile strength has increased from 398.93 to 581.42 MPa with improvement in the ductility from 10.05% to 23.72% at 0.08 wt% gadolinium. The phase transformation temperatures increases as gadolinium increases and reduction in shape recovery ratio from 97% to 65%.
10.1016-j.msea.2018.10.012	1	shape; memory; shape memory; damping; martensite; martensitic; damping capacity; transformation; capacity; strain; superelasticity; temperature; cu-al-mn; shape memory effect; effect	In this study, the microstructure, martensitic transformation, stabilization of the stress-induced martensite and shape memory effect of (Cu78Al12Fe4Mn6)(100-x)Zr-x (x = 1 and 2) and (Cu78Al12Fe4Mn6)(100-y)Nb-y (y = 1 and 2) alloys were investigated. All alloys exhibit bcc phase separation, resulting in a microstructure consisted of dominant L2(1)-Cu2AlMn parent, fine bcc beta(Fe,Al,Zr) or beta(Fe,Al,Nb) phase and a small quantity of 2 H martensite. All the studied alloys show the reversible martensitic transformation, and the forwards martensitic transformation temperatures are below room temperature. Although the alloys have main L2(1) parent before deformation, during deformation and after unloading, the stress-induced 2 H martensite can be stabilized due to the resistance of a large amount of beta(Fe,Al,Zr) or beta(Fe,Al,Nb) particles. Furthermore, the stabilization degree of the stress-induced martensite happens more obviously while further increasing the amounts of particles. The stabilized martensite can be recovered through heating, thus the alloys possess good shape memory properties. The largest shape memory effects are 4.1%, 4.4%, 4.4% and 4.0% respectively for x = 1, 2, and y = 1, 2 alloys.
10.1016-j.msea.2018.10.062	-1		Cu-3 wt% Ag-1 wt% Zr alloy with excellent thermal stability is prepared by rapid solidification technique. The microstructure and mechanical properties as a function of annealing temperatures are investigated. The results indicate that the Cu-3 wt% Ag-1 wt% Zr alloy exhibits a homogeneous microstructure with uniformly distributed nano-sized Ag precipitates and micron-sized Cu4AgZr particles. Moreover, the average grain size is 7 Am without any plastic processing. When annealed at and below 700 degrees C, Ag will precipitate out only by a continuous way, but together with a discontinuous way at 800 degrees C. Furthermore, no significant coarsening of micron-sized Cu4AgZr particles and grains is observed even when exposed at 900 degrees C for 4 h, which results in the excellent mechanical properties of the alloy after annealing at high temperatures. However, the dissolution of micro-sized Cu4AgZr particles results in the abnormal grain growth when annealed at 925 degrees C, which leads to the decrease of hardness and strength .
10.1016-j.msea.2018.10.093	15	aging; strength; conductivity; electrical conductivity; electrical; mpa; treatment; strengthening; degrees; cu-; cold; precipitation; tensile strength; tensile; iacs	Cu-Cr alloys have been widely used in industrial applications owing to their good combination of mechanical properties and electrical conductivity. However, the comprehensive performance of the alloy needs to be further improved to meet the harsh working environment. Hence, in this study, a new type of Cu-Cr alloy with Co and Si additions together with cryogenic rolling (CR) was designed and investigated. Microstructure analysis confirms that the Cr15Co9Si6 and Co2Si phases are formed with Co and Si additions into the Cu-Cr alloy. For the more, partial Cr15Co9Si6 phase decomposes during heat treatment process, and the Co2Si and Cr precipitates are precipitated from matrix during aging process. The improvement of tensile properties of the Cu-1Cr-1Co-0.6Si alloy is mainly attributed to the precipitation strengthening and grain boundary strengthening, and is also benefited from dislocation density strengthening, twin boundary strengthening, and solid solution strengthening. The electrical conductivity of the Cu-1Cr-1Co-0.6Si alloy decreases dramatically mainly due to the increase of impurity scattering caused by surplus Si atoms. CR deformation is helpful for more solute atoms precipitated from the supersaturated solid solution during aging process, and thus the electrical conductivity of the Cu-1Cr-1Co-0.6Si alloy increases with increasing deformation amount. After homogenizing treatment at 900 degrees C for 2 h, hot rolling by 60% at 900 degrees C, solution treating at 990 degrees C for 4 h, cold rolling by 90%, and aging at 440 degrees C for 1 h, the hardness, yield strength (YS), ultimate tensile strength (UTS), and electrical conductivity of the Cu-1Cr-1Co-0.6Si alloy are 214.6 HV, 663.7 MPa, 745.9 MPa and 41.6%IACS, respectively, which exhibit good mechanical properties with a proper electrical conductivity. These results provide a feasible route for developing high performance Cu-Cr alloys.
10.1016-j.msea.2018.10.106	6	grain; deformation; strain; strength; dislocation; cu-; tensile; size; ecap; grain size; sfe; ductility; hardening; high; stress	Three Cu-Al alloys with nominal Al contents of 2.2, 4.5 and 6.9 wt% were subjected to surface mechanical attrition treatment (SMAT) to investigate the effect of stacking fault energy (SFE) on the microstructural feature of gradient structure (GS) layers produced by SMAT and back stress hardening during Bauschinger unloading reloading tests. In the GS layer, the alloys with different SFE exhibit various grain morphologies, grain size distributions and densities and distributions of geometrically necessary dislocations (GNDs). Because of these differences in the microstructural features of the GS layers, the alloys show different variations associated with SMAT during the Bauschinger unloading-reloading tests, i.e. the increment of true stress decreases sharply with a decrease of SFE at small strains, while it slightly decreases at large strains. It is found that SFE can significantly affect grain boundary strengthening and back stress hardening to synthetically improve the tensile strength of GS Cu-Al alloys to different levels.
10.1016-j.msea.2018.11.026	-1		This study focuses on the investigation of uniquely sequenced Cu-Al clad composite wires, which are considered as perspective materials for applications within a wide range of industrial and commercial branches. The wires were produced by rotary swaging under variable temperature (at 20 degrees C and 250 degrees C). The required diameter of the final wire was 5 mm, however, detailed analyses were performed on 10 mm, 7.5 mm, 6 mm and 5 mm samples. The swaged composite wires were studied from the viewpoints of deformation behaviour, structure and mutual interfaces, and electric and mechanical properties via scanning and transmission electron microscopy and neutron diffraction, testing of electrical resistivity, and mechanical testing with implemented acoustic emission detection. The results showed non-negligible effects of both the variables/influencing factors (swaging degree and temperature) on the investigated parameters. The development of intermetallics was observed at the interfaces of samples swaged with high swaging degrees, but only at 250 degrees C. These intermetallics provoked signal activity during acoustic emission detection and deteriorated the electric conductivity. On the other hand, substantial work hardening occurring during swaging at 20 degrees C also decreased the conductivity. By these reasons, the electric properties were the poorest for work hardened samples with occurring intermetallics. Both the final 5 mm composites exhibited satisfactory bonding of both the components and recrystallized structures with ultra-fine grains ensuring the ultimate tensile strength higher than 200 MPa.
10.1016-j.msea.2018.11.045	-1		The effects of pre-deformation on the precipitation behaviors and properties in Cu-Ni-Si-Cr alloy were investigated. The results showed the electrical conductivity and the strength of the alloys after peak aging increased with the pre-deformation amount. Quantitative analyses demonstrated the deformation-induced defects improved the precipitation and the number density of precipitates but reduced their average radii. As a result, the conductivity improved due to the slight promotion of precipitation while the strength increased mostly from the enhanced precipitate strengthening and then from the unremoved work hardening. At elevated temperatures, the effects of pre-deformation were greatly weakened and then the difference among the alloys after different treatments disappeared.
10.1016-j.msea.2018.11.103	6	grain; deformation; strain; strength; dislocation; cu-; tensile; size; ecap; grain size; sfe; ductility; hardening; high; stress	The work hardening behavior and deformation microstructures of pure Cu and Cu-Mn alloys were systemically investigated under uniaxial compression. An anomalous phenomenon of work hardening rate recovery was observed in the present Cu-Mn alloys with high stacking fault energies (SFEs). Such a phenomenon is dramatically distinctive from those observed in previous studies on high-SFE metals, whose work hardening rate monotonically decreases with the increase of strain. Microstructural examinations demonstrate that the occurrence of work hardening rate recovery should be attributed to the transformation from wavy slip to planar slip by increasing Mn content, since these planar slip dislocation structures effectively inhibit dynamic recovery and reduce the dislocation mean free path . Therefore, the possible influencing parameters such as SFE, friction stress, and short-range ordering (SRO) are analyzed. It is suggested that the existence of SRO in Cu-Mn alloys is the main reason causing planar slip. Furthermore, the effect of SRO on the multi-stage work hardening behavior is discussed based on the analyses of dislocation density evolution during deformation. This study enriches a fundamental knowledge of how to improve the work hardening capacity of alloys with high SFEs.
10.1016-j.msea.2018.11.124	1	shape; memory; shape memory; damping; martensite; martensitic; damping capacity; transformation; capacity; strain; superelasticity; temperature; cu-al-mn; shape memory effect; effect	Grains of a Cu-Al-Ni shape memory alloy (SMA) were significantly refined by using the combined refining effect of Cu51Zr14 inoculant and Ti element. With the decrease of grain size, the damping capacity remarkably increased, and the Martensitic transformation (MT) temperatures shifted to low temperature side. Correlated mechanisms have been discussed.
10.1016-j.msea.2018.11.147	6	grain; deformation; strain; strength; dislocation; cu-; tensile; size; ecap; grain size; sfe; ductility; hardening; high; stress	The microstructural stability during long-term storage and tensile deformation have been investigated for nanograined (NG) pure Cu and pure Zr produced by severe plastic deformation. Abnormal and uniform grain growth behaviour is observed in the NG Cu after long-term storage and tensile deformation at different strain rates, respectively. The abnormal grain growth during long-term storage is related to the relaxation of the fluctuating microstrain in the deformed microstructure and can be accelerated by increasing the temperature. The uniform grain growth during tensile deformation is dominated by grain boundary (GB) migration due to the absorption of dislocations. The degree of GB migration in the case of a low strain rate is relatively large owing to the dynamic equilibrium between the formation and disappearance of dislocations. However, the GB migration at a high strain rate is suppressed by the piled-up dislocations. In comparison, the NG Zr exhibits relatively high microstructural stability with no obvious grain growth during long-term storage and tensile deformation. This is attributed to the difference in the crystal structure between Cu and Zr.
10.1016-j.msea.2018.12.011	-1		A complex study of aging kinetics for both coarse-grained and nanostructured by severe plastic deformation Cu-2 wt% Be alloy is reported. It is shown that aging of a coarse-grained alloy leads to continuous formation of nanosized CuBe body centred cubic (bcc, CsCl-type) semi-coherent particles with the {220} Cu // {200} CuBe crystallographic orientation relationship. These particles created significant internal stress fields and became obstacles for dislocation glide that resulted in a change in the hardness from 95 Vickers hardness (HV) for the solubilized alloy to 400 HV for the aged one. The severe plastic deformation led to the formation of a single-phase nanograined microstructure with an average grain size of 20 nm and 390 HV. It was found that this grain size was slightly driven by grain boundary segregation. Further aging of the nanocrystalline alloy led to the discontinuous formation of precipitates on the former Cu grain boundaries and skipping of metastable phases. Significant age hardening with a maximum hardness of 466 HV for the aged nanostructured alloy was observed. Mechanical tests result revealed a strong influence of microstructure and further aging on strength capability of the alloy for both coarse-grained and nanostructured alloy. A good thermal stability in the nanostructured alloy was also noticed. Theoretical calculations of the hardness value for the CuBe phase are provided. It was shown that Be as a light alloying elements could be used for direct change of microstructure of severely deformed copper alloys.
10.1016-j.msea.2018.12.021	6	grain; deformation; strain; strength; dislocation; cu-; tensile; size; ecap; grain size; sfe; ductility; hardening; high; stress	Cu-5.5Al-4.5Zn, Cu-1.9Al-23.9Zn and Cu-1.1Al-2.6Zn (in wt%) alloys with different stacking fault energy (SFE) were prepared by means of surface mechanical attrition treatment (SMAT). Subsequently, gradient structure (GS) was generated in the Cu-Al-Zn alloys, which significantly improved the mechanical properties of the alloys. The influence of SFE on mechanical properties was systematically investigated. The strength of the annealed Cu-Al-Zn alloys increased with the decrease of SFE. The uniform elongation (UE) did not decline with increasing SMAT time in the Cu-5.5Al-4.5Zn alloy. Our results indicate an exceptional combination of high strength and ductility in the Cu-5.5Al-4.5Zn (lowest SFE) alloy processed by SMAT.
10.1016-j.msea.2018.12.075	15	aging; strength; conductivity; electrical conductivity; electrical; mpa; treatment; strengthening; degrees; cu-; cold; precipitation; tensile strength; tensile; iacs	The Cu-4.5Ni-1.2Co-1.0Si-0.15Mg alloy with super-high strength and high electrical conductivity was designed, and a two-step thermo-mechanical treatment was applied to improve the mechanical and electrical properties of the alloy. The microstructure and properties of the alloy were investigated by transmission electron microscope observation, tensile test, hardness and electrical conductivity measurements. The results show that the final alloy treated by two-step thermo-mechanical process has a hardness of 329 HV, a yield strength of 1086 MPa, an elongation of 3.6%, and an electrical conductivity of 30.1%IACS, respectively. The nanoscale beta-Ni3Si and delta-(Co,Ni)(2)Si precipitates form during the thermo-mechanical process, and the addition of the Co could promote the precipitation of delta-(Co,Ni)(2)Si particles. The orientation relationship (OR) between Cu matrix and the precipitates is: (022)(Cu)//(011)(beta)//(010)(delta) and [100](Cu)//[100](beta)//[001](delta). Comparing with the directly aging treatment and one step thermo-mechanical treatment, precipitates that form during the two-step thenno-mechanical process are much smaller and distributed more densely, resulting in the better comprehensive properties of the alloy.
10.1016-j.msea.2018.12.120	-1		Avoiding Sn segregation is vital to produce high performance large scale Cu-Ni-Sn alloys. In this work a low Sn-containing Cu-9Ni-2.5Sn-1.5Al-0.5Si alloy with high strength and ductility was developed by substituting Sn in Cu-Ni-Sn alloy with Al and Si. The results show that Si leads to a bimodal structure, which has coarse unrecrystallization regions with a plenty of < 111 > fiber texture and fine equaixed recrystallization grains. Such a bimodal structure results into good mechanical properties showing a high tensile strength of 861 MPa and a large elongation of 18%, which is comparable to Cu-15Ni-8Sn alloy. The strengthening effects are ascribed to precipitate strengthening, grain refining and twin boundary strengthening in the fine equaixed recrystallization grains and texture strengthening in the coarse unrecrystallization regions.
10.1016-j.msea.2019.01.002	-1		A high performance Cu-Cr-Zr alloy with an ultimate tensile strength of 612 MPa, a uniform elongation of 5% and an electrical conductivity of 84.7% IACS was achieved by the severe rotary swaging and two-step peak-aging treatment. A perfect ultrafine grained microstructure with uniformly distributed nano-precipitates was identified to be responsible for the excellent properties of the studied alloy. The proposed method of rotary swaging in combination with the two-step aging treatment shows good potential for producing the high performance Cu-Cr-Zr alloy, which can not only fulfill the industrial requirement of strength and electrical conductivity, but also is suitable for mass production.
10.1016-j.msea.2019.01.013	-1		The fabrication of carbon nanotubes (CNTs)-reinforced copper matrix composites with excellent performances is a challenging task because of the weak interfacial bonding between CNTs and copper matrices. In the present work, an alloying element titanium was intentionally added to the bonding interfaces of laminated CNTs/Cu composites via the flake powder metallurgy method. Due to the in situ formed intermediate layer of TiC and Cu3Ti particles, the interfacial bonding of the composites was significantly improved. In combination with the architecture design, the locally alloyed 0.2 wt% CNTs/Cu-0.5Ti composite exhibits both improved ultimate tensile strength (407 +/- 22 MPa) and ductility (9.7%) compared with the unalloyed composite containing the same CNT concentration. Since titanium was locally added solely to the interface, the inclusion of titanium had a negligible effect on the lattice parameters of the copper matrix, and the electrical conductivities of the bulk composites were maintained at a relatively high level.
10.1016-j.msea.2019.01.057	-1		The effect of microstructure on the fatigue strength of age-hardened Cu-6Ni-1.5Si alloy was investigated in this study. The aging was conducted at 500 degrees C for 0.5 h for the precipitation of disk-shaped delta-Ni2Si precipitates (continuous precipitates) and 3 h for the discontinuous precipitation of fiber-shaped, stable delta-Ni2Si precipitates to strengthen the Cu matrix. The tensile strength of 0.5 h-aged specimens was about 1.3 times greater than that of the 3 h-aged counterparts, but with inferior electrical conductivity. Despite the considerable difference in tensile strength, no notable difference in fatigue strength was observed between 0.5 h- and 3 h-aged specimens. The 3 h-aged specimens had superior electrical conductivity without sacrificing fatigue strength of the 0.5 h-aged specimens. The physical background of high-cycle fatigue strength in Cu-6Ni-1.5Si alloys with continuous precipitates and discontinuous precipitates is discussed considering the microstructure-sensitive behavior of fatigue cracks.
10.1016-j.msea.2019.01.084	-1		The effect of V addition on the microstructure and mechanical properties of Cu-15Ni-8Sn alloy was systematically investigated in the present study. The results indicate that the significant grain refinement can be achieved by adding trace V content for Cu-15Ni-8Sn alloy, which is ascribed to the formation of V-bearing intermetallic compound. Besides, the addition of V also brings obvious change in the morphology around grain boundary. After solution treatment at 850 degrees C for 4 h, considerable Ni3V particles precipitate from the matrix, which can hinder the grain boundary migration and remain the grain refinement effect. Besides, it can also significantly influence the microstructure and its resulting mechanical properties of the alloy during the subsequent aging process. Moreover, it was found that, after aging treatment at 400 degrees C, Cu-15Ni-8Sn alloy can possess excellent softening resistance with an appropriate addition of V. Namely, it can maintain a high hardness and ultimate tensile strength with the extension of aging time. In addition, the grain refinement and the suppression of discontinuous precipitation by Ni3V particles are believed to be responsible for the improving strength . Especially, when aging for 4 h, the ultimate tensile strength increases from 899 MPa (Cu-15Ni-8Sn) to 990 MPa (Cu-15Ni-8Sn-0.4V). The optimal comprehensive performance can be obtained for Cu-15Ni-8Sn-0.4V alloy with a hardness (368 HV), ultimate tensile strength (990 MPa), electrical conductivity (8.03%IACS) when aging at 400 degrees C for 4 h .
10.1016-j.msea.2019.02.019	-1		Currently, advanced ODS copper alloy is under study as a potential fusion material providing good mechanical properties. In this work, in order to develop a high performance ODS copper containing 0.5 wt% Y2O3 oxide particles, the effect of room temperature rolling and subsequent annealing on the grain structure evolution, texture development and tensile properties are studied using EBSD, TEM and tensile tests. Microstructure evolution studies show the grain structure coarsens by enhancing the Brass texture during increase of rolling reduction and a unique single crystal-like brass-texture deformed structure is achieved after 80% rolling reduction. We found the deformation mechanism of partial slip by a/2 211 dislocations facilitated by the pinning of a/2 101 perfect dislocations through fine oxide particles is responsible for formation of Brass texture during room temperature rolling. Furthermore, the recrystallization of ODS copper retards to high temperature of similar to 700 degrees C and shows a fine-grained microstructure with different orientations of Goss, Brass, S and Copper. Evaluation of microstructure-mechanical properties of the recrystallized samples expresses that the bimodal grain size distribution at 800 degrees C for 30 min offers a good tensile strength-ductility (UTS: 491 MPa, el(t): 19%) at ambient temperature.
10.1016-j.msea.2019.02.033	1	shape; memory; shape memory; damping; martensite; martensitic; damping capacity; transformation; capacity; strain; superelasticity; temperature; cu-al-mn; shape memory effect; effect	In this study, the cast Cu-13.96Al-9.84Mn-0.51W shape memory alloy consisted of L2(1)-Cu2AlMn parent with completely coherent bcc A2(W) nanoparticles due to bcc phase separation. The abnormal grain growth happened only through annealing cast polycrystalline alloy. The results showed that a continuous misorientation gradient within the matrix grains with a deviation of below 2 formed after the dissolution of A2(W) nanoparticles during annealing. This continuous misorientation gradient may result in the abnormal grain growth . The single crystal specimens were directly obtained from one of large grains. The single crystal close to [100] orientation exhibited very excellent superelasticity and fatigue resistance. Here full superelasticity up to 12% and the largest super elastic strain up to 8.5% were displayed, being comparable to commercial Ni-Ti shape memory alloys. Furthermore, the single crystal almost remained full superelasticity during 5 x 10(3) cycles. From the points of raw material cost, preparation technology and functional properties, the Cu-Al-Mn-W single crystal shows good potential as new superelastic material.
10.1016-j.msea.2019.02.036	15	aging; strength; conductivity; electrical conductivity; electrical; mpa; treatment; strengthening; degrees; cu-; cold; precipitation; tensile strength; tensile; iacs	Cu-0.47Cr-0.16 Nb (wt%) alloys were designed and prepared, and the microstructures of the Cu-Cr-Nb alloy were investigated using transmission electron microscopy and three-dimension atom probe tomography technique. After homogenizing at 950 degrees C for 4 h, cold rolling by 80% reduction, then aging at 450 degrees C for 30 min, the micro-hardness, electrical conductivity, tensile strength, yield strength and elongation of the alloy were up to 150 HV, 89.1%IACS, 453 MPa, 443 MPa and 11.4%, respectively. The tensile strength / elongation of the alloy approached 399 MPa / 22.9% as test at 200 degrees C, 334 MPa / 14.8% for 300 degrees C, and 282 MPa / 12.3% for 400 degrees C, respectively. The Cr2Nb phase with an average size of 700 nm and Nb phase with an average size of 500 nm formed during the solidification process, while the nano-scale Cr-rich phases precipitated from the solid solution during the aging process. The sizes of Cr2Nb and Cr-rich phases were close to each other during aging. These precipitates located in the grain and sub-grain boundary could effectively pin the movement of boundary, resulting in a high strength of the alloy at the elevated temperature. The addition of Nb can promote the precipitation of Cr from the solid solution during aging, thus both strength and electrical conductivity of the alloy were improved.
10.1016-j.msea.2019.02.073	15	aging; strength; conductivity; electrical conductivity; electrical; mpa; treatment; strengthening; degrees; cu-; cold; precipitation; tensile strength; tensile; iacs	The microstructure and subsequent re-aging behavior of Cu-15Ni-8Sn alloy pre-deformed with dynamic strain aging (DSA) were investigated. The results show that DSA has an inhibitory effect on spinodal decomposition and result in the segregation and clustering of Sn and Ni, and eventually leads to the precipitation of Ni3Sn. DSA pre-treatment can significantly shorten the peak aging time of re-aging process since the precipitation of the strengthening phases grow directly from the dynamically precipitated nanoparticles in the previous DSA without time-consuming spinodal decomposition and nucleation.
10.1016-j.msea.2019.03.022	-1		In this study a Cu-12wt%Al-3wt%Ni-0.6wt%Ti + RE high temperature shape memory alloy, where RE denotes the rare earth doping elements, was prepared by vacuum arc melting and characterized by means of scanning electron microscopy, field emission scanning electron microscopy, transmission electron microscopy, X-ray diffraction at room and elevated temperatures, differential scanning calorimetry, tensile test and dynamic mechanical analysis. The results demonstrated that the addition of a 0.04 wt% RE to the initial alloy caused a significant grain size reduction, improved the ductility and enhanced the thermo-mechanical properties. As a consequence of the addition of RE, both the tensile fracture stress and tensile fracture strain of the alloy increased from 550 MPa and 4.50% to 660 MPa and 5.0%, respectively. The maximum recoverable strain was raised from 1.2% to 1.8%. A significant improvement of the mechanical properties and shape memory response of this alloy was attributed to the extra grain refinement mainly due to the formation of the RE-rich precipitates.
10.1016-j.msea.2019.03.024	4	transformation; martensite; martensitic; phase; shape; beta; memory; shape memory; temperature; temperatures; martensitic transformation; gamma; transformation temperatures; effect; thermal	In the present study, we have investigated the influence of aging heat treatments on the microstructure, mechanical properties and shape memory effect on a spray-formed Cu-Al-Ni-Mn alloy with minor Nb additions. The samples were homogenized and subsequently aged at distinct temperatures in order to obtain different microstructures and structural ordering states. The effects of aging heat treatment on the initial microstructure and on mechanical properties were evaluated. Also, shape memory effect was tested in terms of recovery strain epsilon(emf) (%), residual strain epsilon(r) (%) and recovery ratio (R) in different thermomechanical conditions. The compressive fracture stress reached 1400 MPa with a fracture elongation of 19% for the sample with microstructure composed of the austenite beta, martensite beta' and the intermetallic AlNb3. For the same condition, the recovery strain was 1,76% and recovery ratio was 42%. Furthermore, it is proposed one mechanism based on the hampering of the phase transformation by Nb rich precipitates. It can be considered as a new route to improve mechanical property, ductility and the shape memory effect at the same time.
10.1016-j.msea.2019.04.004	-1		A bulk Cu-0.55Cr-0.2Zr alloy with structure of ultra-fined grains (UFGs), nanograins (NGs) and nano precipitates in grain boundaries (GBs) was fabricated by cryogenic friction stir processing (CFSP) followed with annealing treatment. A combination of high strength, pronounced electrical conductivity, and good microstructure thermal and mechanical stability was achieved.
10.1016-j.msea.2019.04.022	-1		This paper presents an investigation of the effect of zirconium on the properties of polycrystalline Cu-Al-Be shape memory alloy. Mechanical and shape memory properties have been evaluated by varying the compositions of Zr to Cu-88.13-Al-11.42-Be-0.45 alloy ranging from 0.05 to 0.4 wt% with step 0.1 wt%. The results unveil reduction in the grain size of 89.18% with the improved tensile strength of 667 +/- 30 MPa and ductility of 23.95 +/- 0.86% and excellent shape recovery ratio of 100% with the addition of Zr up to 0.3 wt%. Increase in transformation temperatures is observed with the addition of Zr.
10.1016-j.msea.2019.04.032	-1		For metal matrix composites (MMCs), the sintering temperature is of vital importance in realizing a dense bulk material with tight interfacial adhesion as well as limited structural damage to reinforcements. In this work, we investigated the influence of the spark plasma sintering (SPS) sintering temperature on the microstructure and mechanical properties of the in-situ synthesized discontinuous three-dimensional graphene-like network (3D GN) reinforced copper matrix composites. It demonstrates that with the rise of the sintering temperature from 600 degrees C to 700 degrees C, the GN distribution changes from intergranular type to intragranular type as a result of the significant improvement in interfacial wettability. Furthermore, the overall mechanical performance (both tensile strength and ductility) of the GN/Cu composites presents an unanticipated declining trend at elevated sintering temperatures. Integrated with microstructure characterization and the theoretical analysis, it is verified that the change of the reinforcement size and its distribution are the dominant factors. Their contributions to the mechanical properties of the composites were also studied in detail.
10.1016-j.msea.2019.04.038	6	grain; deformation; strain; strength; dislocation; cu-; tensile; size; ecap; grain size; sfe; ductility; hardening; high; stress	Analyses of the microstructures, plastic deformation behaviours and fracture behaviours with respect to annealing conditions are presented for Cu-3wt%Ag-0.5wt%Zr sheets rolled to achieve a 90% overall thickness reduction at room temperature. The results show that the starting temperatures of recovery and recrystallization are approximately 200 degrees C and 400 degrees C, respectively. The microstructural evolution manifests as the lamellar boundaries disappearing and sub-grains (SGs) coarsening during recovery. The average size of the dislocation cell (d(DC)) is clearly elevated during recrystallization. By constructing relationships among mobile dislocation density (rho(m)), dislocation mean free path (L) and d(DC), a constitutive equation is built for describing plastic deformation behaviour. The parameters of the simplified Kubin-Estrin (KE) and new model describing mobile dislocation multiplication, mutual annihilation, dynamic recovery, L and d(DC) are related to the annealing conditions. A microstructure with a larger d(DC) value possesses a higher strain-hardening capacity, which leads to a large unstable plastic deformation stage and a large shear dimple region on the fracture surface.
10.1016-j.msea.2019.04.053	15	aging; strength; conductivity; electrical conductivity; electrical; mpa; treatment; strengthening; degrees; cu-; cold; precipitation; tensile strength; tensile; iacs	The mechanical properties and microstructure transformation of Cu-Cr-Zr alloys obtained by upward continuous casting with varying Zr contents were studied by optical microscopy (OM), electron backscattered diffraction (EBSD) and transmission electron microscopy (TEM) after cold drawing with different strain and heat treatment. The results show that good strength can be obtained through cold drawing with suitable heat treatment. The peak tensile strength can achieve 587.8 MPa and the peak yield strength can reach 499.6 MPa; The difference of yield strength of Cu-Cr-Zr alloy during cold drawing deformation becomes larger with the increase of Zr element content when the strain gradually improves; The increase of the Zr element will promote the recrystallization of the alloy at aging after cold drawing, refining the crystal grains. It contributes about 70% of the increase in strength, act as a fine grain strengthening effect, increasing the strength of the alloy.
10.1016-j.msea.2019.04.061	6	grain; deformation; strain; strength; dislocation; cu-; tensile; size; ecap; grain size; sfe; ductility; hardening; high; stress	Commercial pure copper was processed at room temperature by accumulative roll bonding (ARB) up to 7 cycles. High-Resolution-Transmission-Electron-Microscope (HRTEM), X-Ray Diffraction (XRD) analyses, tensile and hardness measurements were carried out to interpret the interplay between lattice strain, stacking faults, microstructure evolution and mechanical properties of pure copper during ARB. ARBed Cu was obtained with 27 nm crystallite size achieving 351%, 137%, and 159% enhancements in yield strength, tensile strength, and hardness, respectively. XRD analyses revealed an increase in the dislocation density with reductions in the lattice strain and the effective Stacking Fault Energy (SFE). The decrease in the SFE promoted the generation of new dislocations and extended the dislocation saturation limit up to 6 cycles. Moreover, it was revealed that the grain subdivision significantly influences the lattice strain and the rate of dislocation increase. The decrease in the lattice strain was accompanied with an increase in ductility. Due to a reduction in the SFE of the processed copper, stacking faults were observed in the lattice structure and similar to 60% enhancement in ductility over cold rolled samples was obtained. The assessment of strengthening mechanisms revealed that 55% of the strengthening is due to grain subdivision and 45% is due to strain hardening.
10.1016-j.msea.2019.04.069	6	grain; deformation; strain; strength; dislocation; cu-; tensile; size; ecap; grain size; sfe; ductility; hardening; high; stress	In current work, various soft/hard copper/bronze laminates with transition interfaces and superior mechanical properties were fabricated by three primary processing steps: diffusion welding, cold rolling and annealing (DCA). The superior combinations of strength and ductility for copper/bronze laminates were mainly attributed to back-stress hardening induced by well-bonded transition interfaces. Back-stress hardening was affected by the microstructures and hardness ratio of soft/hard layers. High density dislocations both in original soft and hard layers can weaken the back-stress hardening (ductility). For the dislocation-free copper/bronze laminates, a reasonable high hardness ratio between hard and soft layers can generate a larger strain gradient so as to produce higher back-stress hardening. This work provides a new structural design strategy for metallic materials to simultaneously improve their strength and ductility.
10.1016-j.msea.2019.04.073	6	grain; deformation; strain; strength; dislocation; cu-; tensile; size; ecap; grain size; sfe; ductility; hardening; high; stress	An analysis of phases precipitation during the supersaturated solid solution (SSSS) decomposition in binary Cu-Cr, Cu-Hf and ternary Cu-Cr-Hf alloys after equal-channel angular pressing (ECAP) was carried out. ECAP affects the ageing kinetics by changing the sequence of phase precipitation, and accelerates the decomposition of SSSS.
10.1016-j.msea.2019.04.074	6	grain; deformation; strain; strength; dislocation; cu-; tensile; size; ecap; grain size; sfe; ductility; hardening; high; stress	Steady-state creep behavior of rolled Cu-8Cr-4Nb (GRCop-84) production sheet was systematically studied at temperatures from 673 to 1073 K (0.50-0.79 T-m). Threshold behavior was observed at high temperatures and low stresses which can be phenomenologically described by a threshold stress model. The threshold stress obtained by a non-linear regression method ranges from 0.2 to 0.3 of the Orowan stress, which suggests that dislocations locally climb over particles with an activation energy approximately equal to that of lattice diffusion. Power-law breakdown was observed at low temperatures and high stresses, which can be phenomenologically described by a hyperbolic sine model. A unifying model is proposed to predict the creep properties of both the production sheet and previously-studied extruded material. Generally, GRCop-84 production sheet creeps faster than the extruded form due to the difference in crystallographic texture. No observable effects caused by microstructural differences are noted to influence the steady-state creep behavior of the two differ. ently processed forms of GRCop-84. The post-fracture morphology of the production sheet closely resembles that of the extruded material indicating ductile fracture caused by micro-void coalescence.
10.1016-j.msea.2019.04.075	6	grain; deformation; strain; strength; dislocation; cu-; tensile; size; ecap; grain size; sfe; ductility; hardening; high; stress	Experiments were performed to analyze the microstructural evolution and mechanical behavior of commercial purity copper (99.8%) processed by up to 48 cycles of multi-directional forging (MDF) using a low strain amplitude of similar to 0.075 (total accumulated strain epsilon approximate to 10.8). Parabolic work-hardening concomitantly with increasing dislocation densities was observed up to epsilon approximate to 2, followed by a practically constant flow stress due to dynamic recovery. The average grain size was reduced from 30.5 mu m in the annealed metal down to 4.1 mu m for epsilon approximate to 7.2; the fraction of sub-micrometric grains reached similar to 12% for epsilon approximate to 10.8. The microstructural changes were attributed to the fragmentation of the original grains by dislocation structures having low misorientation angles which gradually evolved into arrays of high-angle grain boundaries with increasing numbers of MDF cycles. The Cu samples subjected to 48 cycles of MDF displayed limited dynamic recrystallization, exhibiting basically dislocation cells and sub-grains with an average size of 0.6 mu m. It is demonstrated that low strain amplitude MDF delays the kinetics of grain refinement in copper compared with MDF using higher strain amplitudes.
10.1016-j.msea.2019.04.092	-1		Cu/Zn/Al multilayered composites consisting of pure copper, zinc, and aluminum were produced by accumulative roll bonding. Afterwards, heat treatment processes at various temperatures (750, 825, and 900 degrees C) were followed on the prepared composites to fabricate Cu-Zn-Al shape memory alloys. The prepared samples were characterized by scanning electron microscopy equipped with energy dispersive X-ray spectroscopy and X-ray diffraction. Mechanical properties of the composites and alloys were also investigated by hardness and tensile tests. The shape memory effect of the prepared alloys was evaluated by bending tests and subsequent heating. The results presented that the fabricated composite has a homogeneous distribution of Zn and Al layers in the Cu matrix. It was also found that the alloys treated at 750 and 825 degrees C consist of a and martensite phases, whereas only 18R martensite is formed in the alloy fabricated at 900 degrees C. Additionally, the alloy annealed at 900 degrees C exhibited a good strength (about 500 MPa), ductility (about 22%) and shape memory effect. It was concluded that Cu-Zn-Al shape memory alloys can be successfully fabricated by accumulative roll bonding and subsequent heating treatment processes.
10.1016-j.msea.2019.04.110	-1		The trace Hf element (0.2 wt%) was added into the Cu-0.4Cr-0.2Zr (wt%) alloy to achieve synchronous improvements in strength, ductility and electrical conductivity. The roles of the Hf element in the microstructural evolution and the mechanical and electrical properties were investigated via transmission electron microscopy (TEM), X-ray line broadening analysis and tensile tests. The results showed that the trace Hf element effectively decreased the stacking fault energy of copper alloys. The synergetic effect of the Hf element and the intermediate aging treatment contributed to the formation of high-density dislocations, profuse deformation twins and refined deformation bands in the Cu-0.4Cr-0.2Zr-0.2Hf alloy, thereby enhancing its tensile strength by similar to 51 MPa. The addition of Hf also significantly improved the ductility of the copper alloys due to the presence of deformation twins. High strength (628 MPa), high ductility (similar to 5%) and high electrical conductivity (80.35% IACS) have been achieved simultaneously in the Cu-0.4Cr-0.2Zr-0.2Hf alloy subjected to the intermediate aging treatment.
10.1016-j.msea.2019.05.003	15	aging; strength; conductivity; electrical conductivity; electrical; mpa; treatment; strengthening; degrees; cu-; cold; precipitation; tensile strength; tensile; iacs	A novel Cu-1.01%Ni-0.28%Si-0.14%Co-0.45%Cr (mass percent) alloy with high strength and high conductivity was fabricated. Microstructure, mechanical and electrical properties of the alloy after multi-stage thermo-mechanical treatment were investigated in detail. The alloy has excellent comprehensive properties, with a tensile strength of 810 MPa, yield strength of 777 MPa, elongation of 3.4%, and electrical conductivity of 57.5%IACS (International Annealing Copper Standard). Three kinds of precipitates, (Cr,Co)(2)Si, (Ni,Co)(2)Si and Cr, form during aging treatment. Addition of Co element promotes the precipitation of Cr, Ni and Si solute elements from the matrix, while inhibits the growth of the (Cr,Co)(2)Si. The high strength of the alloy treated by multi-stage thermo-mechanical process is attributed to the dispersion strengthening, sub-structure strengthening, and work hardening. The multi-aging process and addition of Co effectively improve the electrical conductivity of the studied alloy. The high strength and high conductivity of studied alloy make it as a potential candidate for lead frame materials in electrical and electronics industry.
10.1016-j.msea.2019.05.051	-1		The study investigated the effect of nickel content on the microstructure and mechanical properties of Cu-12Al-xNi alloys prepared using powder metallurgy. The results indicated that the alloys investigated consisted of alpha-Cu and gamma(2) (Al4Cu9), containing less than 4 wt% Ni content. The alpha-Cu phase gradually increased, while the gamma(2) (Al4Cu9) phase gradually decreased as the sintering temperature increased. Both the strength and hardness of the alloy thus reduced. When the Ni content increased above 4 wt%, the NiAl phase precipitated at the grain boundaries, which resulted in an increase in the strength of the alloy. Additionally, the tensile strength reached a maximum of 390 MPa when the Ni content reached 6 wt%. The decrease in the tensile strength for higher Ni content was attributed to the formation of a NiAl phase network. And the addition of nickel did not significantly alter the sintering density of the alloy. The mechanisms of microstructure evolution and strengthening mechanisms were investigated and discussed.
10.1016-j.msea.2019.138048	-1		High-strength, high-conductivity silver-copper composite wires were prepared by powder metallurgy, spark plasma sintering and room-temperature wire-drawing. Silver nanowires were mixed with a commercial micrometric copper powder (1, 5 and 10 vol% silver). The powders were consolidated by spark plasma sintering in cylinders, which served as precursors for room temperature wire-drawing, producing samples of wires with progressively decreasing diameters. The Vickers microhardness for the wires is higher than that for the cylinders, reflecting both densification and grain refinement. Investigation of the microstructure reveals that the silver nanowires are located at the grain boundaries of ultrafine copper grains, elongated over several micrometers. The electrical resistivity and tensile strength were measured at 293 K and 77 K. The tensile strength is more than twice for the composite wires compared to the corresponding pure copper wires. Although higher tensile strengths are obtained using 5 vol% Ag, the wires containing only 1 vol% Ag offer the best combination of high strength (1100 +/- 100 MPa at 77 K) and low electrical resistivity (0.50 mu Omega cm). The 1 vol% Ag-Cu composite wires compare favorably with Ag-Cu alloy wires containing about 20 times more silver.
10.1016-j.msea.2019.138068	15	aging; strength; conductivity; electrical conductivity; electrical; mpa; treatment; strengthening; degrees; cu-; cold; precipitation; tensile strength; tensile; iacs	The contradictory relation between the strength and electrical conductivity of Cu-Ni-Si alloy after cold deformation is a significant scientific issue, break the contradictory relation is an important challenge for preparing the Cu-Ni-Si alloy with high strength and electrical conductivity. The C70250 copper alloy strips were prepared by temperature controlled mold continuous casting (TCMCC) and cold rolled. The effects of different cold rolling reduction rates on mechanical properties and electrical conductivity of the alloy were investigated, and the mechanism was revealed. The results indicate that the C70250 copper alloy strip prepared by TCMCC can be directly cold rolled with large deformation. When the cumulative cold rolling reduction rate reaches 97.5%, the strength and electrical conductivity of the alloy increase by 327 MPa and 0.6 %IACS, respectively. With the increase of cold rolling reduction rate, the shear deformation degree of columnar grain structure with strong [001] orientation increases gradually in C70250 copper alloy prepared by TCMCC. The alloy forms a large number of parallel shear bands consisting of high density dislocations, which seriously hinder the slip of dislocations and lead to the continuous increase of strength of the alloy. The parallel distributed shear bands in the C70250 copper alloy uniformly cut the matrix during the cold rolling process, and finally form a fibrous-shaped microstructure. The transverse grain boundary density is significantly reduced after cold deformation, which greatly reduces the influence of transverse grain boundary on the electrical conductivity and leads to abnormal increase of the electrical conductivity of the alloy.
10.1016-j.msea.2019.138108	10	composites; nanoparticles; strength; matrix; high; strengthening; particles; conductivity; composite; electrical; mpa; sintering; ods; grains; mechanical	Cu-0.3 wt% Zr alloys incorporated with varying ZrB2 levels were prepared by adjusting Zr/B addition rates via in-situ synthesis. Micro-scale ZrB2 particles formed through in-situ reactions between Zr and B in copper melt and nano-scale Cu5Zr precipitates formed upon aging treatment. The composites thus produced exhibited desired combination of mechanical properties and electrical conductivity. This paper investigates the effects of cryorolling and aging treatment on the microstructures and properties of the composites. Compared with traditional rolling process, the ultimate tensile strength of cryorolled Cu-0.3Zr-1ZrB(2) composites increased from 541.9 MPa to 599.6 MPa without sacrificing too much electrical conductivity. The contributions of different strengthening mechanisms due to the dual-scale particles, twins, and dislocations were quantitatively calculated and the results showed good agreement with the experimentally measured data. Also revealed in this work is that the mechanical performance of Cu-0.3Zr-xZrB(2) composites is relatively superior with respect to Cu-0.3Zr at 573 K, indicating that ZrB2 is in favor of enhancing the resistance to thermo-softening.
10.1016-j.msea.2019.138132	-1		As a high strength wearproof alloy, Cu-15Ni-8Sn alloy structures were fabricated by selective laser melting (SLM), while they possessed poor mechanical properties due to the absence of precipitated phase, and thus they are on the halfway to industrial application. SLM-processed Cu-15Ni-8Sn alloy subjected to heat treatments is studied to further improve the performance. Microstructure evolutions and mechanical properties variations were investigated, and the strengthening mechanisms are discussed. SLM-processed matrix is a supersaturated solid solution with fine grains, leading to important yield strength contributions from solid solution strengthening. The incremental strength for heat-treated samples aged at 400 degrees C is mainly due to the DO22 ordering and the spinodal decomposition. The precipitation strengthening increased from 1.4% to above 70% after heat treatment. Among the three aging methods, directly aging (DA) samples showed highest strength than the other two methods. The directly aged samples exhibit fine grains and high dislocation density, resulting in high grain boundary strengthening and dislocation strengthening. Moreover, direct aging treatment is an economical and environment-friendly way to improve mechanical properties of SLM-processed precipitation-hardened alloy, which is a high strength conductive elastic material.
10.1016-j.msea.2019.138299	6	grain; deformation; strain; strength; dislocation; cu-; tensile; size; ecap; grain size; sfe; ductility; hardening; high; stress	To explore the influence of deformation microstructures on the evolution of gain boundary character distribution (GBCD), various thermo-mechanical processes (TMPs) were carried out on the Cu-16at%Al alloy. The deformation microstructures of all cold rolled samples and the evolution process of twin related domains (TRDs) during subsequent annealing were revealed by transmission electron microscope (TEM) observations and quasi in situ electron back scatter diffraction (EBSD) observations, respectively. Besides, the influence of GBCD optimization on the mechanical property was also examined by uniaxially tensile tests. The results show that the deformation microstructures including stacking faults (SFs) and deformation twins (DTs) have significant effects on the evolution of TRDs and thus on the GBCD optimization. SFs are beneficial to GBCD optimization, for which the formation of annealing twins (ATs) can be induced by generating stacking accidents in a sequence of closely packed atomic planes at the front end of growing TRD. On the contrary, DTs hinder the growth of TRDs, thus impairing GBCD optimization. The optimal prior strain of TMP for the GBCD optimization of the Cu-16at. %Al alloy is thus suggested to be around the threshold strain for the appearance of DTs. Under the premise for the absence of obvious differences in yield strength and ultimate tensile strength, the tensile ductility of the GBCD optimized Cu-16at%Al alloy is improved, due to an increased deformation uniformity and a higher resistance of AT boundaries to crack propagation.
10.1016-j.msea.2019.138349	6	grain; deformation; strain; strength; dislocation; cu-; tensile; size; ecap; grain size; sfe; ductility; hardening; high; stress	In order to clarify the contribution of dislocation-hydrogen interaction on the hydrogen embrittlement (HE) of pure Ni and of Cu-55 wt% Ni binary alloy, slow strain rate tensile (SSRT) tests were conducted at room temperature (RT) and at 77 K on hydrogen-precharged specimens. Regarding the SSRT test at RT, hydrogen increased the flow stress and induced intergranular fracture in both pure Ni and Cu-Ni alloy. Furthermore, based on scanning transmission electron microscopy investigations, it was suggested that the evolution of dislocation structures had been enhanced by hydrogen, but only in the case of pure Ni. At 77 K, the ductility of pure Ni was degraded by hydrogen, whereas that of Cu-Ni alloy was not. The difference in temperature dependence of the dislocation-hydrogen interaction between pure Ni and Cu-Ni alloy was discussed, based on the previously proposed HE mechanisms.
10.1016-j.msea.2019.138350	-1		This investigation examines the problem of homogenization in metal matrix composites (MMCs) and the methods of increasing their strength using severe plastic deformation (SPD). In this research MMCs of pure copper and silicon carbide were synthesized by spark plasma sintering (SPS) and then further processed via high-pressure torsion (HPT). The microstructures in the sintered and in the deformed materials were investigated using Scanning Electron Microscopy (SEM) and Scanning Transmission Electron Microscopy (STEM). The mechanical properties were evaluated in microhardness tests and in tensile testing. The thermal conductivity of the composites was measured with the use of a laser pulse technique. Microstructural analysis revealed that HPT processing leads to an improved densification of the SPS-produced composites with significant grain refinement in the copper matrix and with fragmentation of the SiC particles and their homogeneous distribution in the copper matrix. The HPT processing of Cu and the Cu-SiC samples enhanced their mechanical properties at the expense of limiting their plasticity. Processing by HPT also had a major influence on the thermal conductivity of materials. It is demonstrated that the deformed samples exhibit higher thermal conductivity than the initial coarse-grained samples.
10.1016-j.msea.2019.138390	14	strength; properties; conductivity; electrical; mechanical; cu-; grain; mpa; electrical conductivity; aging; precipitation; phase; mechanical properties; tensile; phases	An in-depth exploration of the microstructure evolution and characterization of the precipitates in a quaternary Cu-Ni-Co-Si alloy under different aging conditions was conducted. The precipitates were confirmed to be delta-(Ni, Co)(2)Si and exhibited different morphological features with high-resolution transmission electron microscopy. The three-dimensional atom probe technique revealed the quantitative atomic distribution and corresponding content changes in the precipitates. Combined with the above analysis, these results allowed the evolution of the delta-(Ni, Co)(2)Si precipitates to be determined. The precipitation phase was divided into two zones: unstable zone I at the edge and zone II comprising pure delta-(Ni, Co)(2)Si in the core. As aging progressed, the thickness of zone I decreased, and that of zone II increased continuously, accompanied by the replacement of Cu atoms in the precipitates by external Ni atoms. In the peak-aged state, the Ni, Co and Si atoms exhibited a substantial amount of cosegregation, and the corresponding atomic concentrations were 40 at%, 25 at% and 35 at%, respectively. The studied alloy exhibited excellent comprehensive properties, including a hardness of 318 HV, an electrical conductivity of 37.1% IACS, a tensile strength of 1003 MPa, a yield strength of 929 MPa, and an elongation of 4.5%, after the introduction of a multistage thermomechanical treatment process. Theoretical analysis was conducted for different strengthening mechanisms, and the findings coincided well with the experimental results.
10.1016-j.msea.2019.138432	1	shape; memory; shape memory; damping; martensite; martensitic; damping capacity; transformation; capacity; strain; superelasticity; temperature; cu-al-mn; shape memory effect; effect	Stress relaxation resistance is one of the key properties needed to shape memory alloys (SMAs) in the applications of fasteners, elastic contact components, etc. In this work, the stress relaxation behaviors in the superelastic (SE) and shape memory processes of columnar-grained (CG) Cu-Al-Mn SMAs were investigated under constant strain conditions for 100 h . The effects of loading strain and ambient temperature on the stress relaxation resistance was studied experimentally. The experimental results indicated that the stress relaxation resistance of CG Cu71.3Al17.0Mn11.7 SMAs could reach over 85% and 62% at 25 degrees C and 60 degrees C, respectively, at a loading strain of 2%similar to 10%. The SE stress relaxation resistance almost remained constant in the martensite transformation stage; however, it linearly declined with increasing ambient temperature. The stress relaxation resistance for one-way and two-way shape memory effects (OWSME and TWSME) also reached 70% and 66%, respectively, in CG Cu72.7Al16.8Mn10.5 SMAs. The SE, OWSME and TWSME stress relaxation behaviors could be well described by a logarithmic model.
10.1016-j.msea.2019.138592	-1		A quantitative investigation on the influence of precipitation process and kinetics on the Young's modulus evolution and strengthening mechanism of a Cu-1.95 wt% Be alloy is conducted to in this paper. It is proved by both experimental and theoretical analysis that continuous precipitation of Cu-Be alloy is initiated by the coexistence of ordering and decomposition. The Young's modulus of Cu-Be alloy is found increasing from 114 to 115 GPa to higher than 130 GPa when aged at 593 K. The highest modulus is obtained in specimens aged at 593 K for 1 h and 16 h, corresponding to the microstructures containing G.P. zones & gamma '' precipitates, and gamma' & gamma precipitates, respectively. The Young's modulus increases very slowly or even remains steady with aging time in range of 2 h-12 h . The evolution of Young's modulus is attributed to the combing effect of the continuous precipitation and the composition variation of Be atoms in matrix simultaneously, according to the quantitative analysis by a mathematical model and a finite element model. The strain-field generated by precipitations is found to be another important factor on modulus. The precipitation strengthening mechanism is investigated by a comprehensive theoretical model, to reveal the probability and contributions of the two dislocation pinning mechanisms, i.e., dislocation by-shearing and by-passing effects. Dislocation by-shearing is considered as the leading strengthening mechanism during the initial stage of precipitation, yet it will be weakened as aging time increases.
10.1016-j.msea.2019.138656	-1		The uniform dispersion of carbon nanotubes (CNTs) in copper matrix and the formation of strong interfacial bonding between copper matrix and CNTs are two major challenges for the synthesis of the carbon nanotubes/copper (CNTs/Cu) composites. In this paper, the Cu/CNTs and Cu/CNTs-1 composites were successfully prepared by using two different precursor preparation technologies which are alloying method (AM) and co-deposition method (CM), chemical vapor deposition (CVD) and spark plasma sintering (SPS) technique. The results show that the carbon nanotubes prepared by AM have better quality, more homogeneous diameter and higher graphitization degree compared with CM. The mechanical properties of the Cu/CNTs composites (by AM) is improved owing to the strong interfacial bonding and the high load transfer efficiency. The hardness of the Cu/CNTs composites is 102.5 HV, which is increased by 24.7% and 6.5% in contrast with that of pure copper and Cu/CNTs-1 composites (by CM), respectively. And the tensile strength is 275 MPa, which is improved 36.1% and 16.0%. Furthermore, the electrical conductivity of the Cu/CNTs composites keeps at a high level of 92.9%IACS. And the alloying method is simple, feasible, replicable and easy to achieve the goal of the industrial preparation. So this work provides guidance for preparing copper-based composites with good electrical conductivity and excellent mechanical properties.
10.1016-j.msea.2019.138811	6	grain; deformation; strain; strength; dislocation; cu-; tensile; size; ecap; grain size; sfe; ductility; hardening; high; stress	The pure copper sheets were rolled with a small strain in one pass at cryogenic and room temperature, respectively. The total thickness was reduced by 55% through three rolling passes. The microstructural evolution and mechanical properties of Cu sheets were investigated by metallographic characterizations, tensile tests and fracture analysis. It is found that several nanoscale mechanical twins are generated in the cryogenically rolled Cu sample. The restricted atomic motion at ultralow temperature inhibits the dislocation slip and then induces the occurrence of grain kinking and mechanical twining. The yield strength and ultimate tensile strength of cryorolled Cu sample are enhanced by the remarkable accumulation of dislocations and mechanical twins. During annealing treatment, the recrystallization behavior is accelerated by the dramatic strain energy and microstructural defects in cryogenically rolled Cu samples. Compared with the recrystallization concentrated on the surface of room temperature rolled Cu sample, a few of recrystallized grains are formed in the central position of cryogenically rolled Cu sample at 180 degrees C annealing. The rapid progress of thermal recovery during annealing treatment improves the tensile ductility and strain-hardening capacity of cryo-rolled Cu sample. Several pores are formed on the tensile fracture due to the incompatible deformation between the inhomogeneous grains. The results demonstrate that combining the cryogenic rolling and 200 degrees C annealing is able to improve the mechanical properties of pure copper sheet.
10.1016-j.msea.2019.138818	-1		In this work, the hardness, electrical resistivity and thermal stability of annealed Ag/Nb multilayers were investigated with individual layer thickness (h) ranging from 3 to 100 run after annealing at 200-400 degrees C. For all scales multilayers, the hardness improves 6-16% whereas the electrical resistivity decreases 6-12% after annealing at 200 degrees C compared with those of as deposited state. At 300 degrees C, the enhancement shows layer thickness dependent due to the different interfacial structures. The hardness improves about 4-10% and the electrical resistivity decreases 11-28% for multilayers with h >= 10 nm. A good combination of high strength and high conductivity has been obtained in annealed Ag/Cu multilayer with h >= 10 nm when annealing temperature is not more than 300 degrees C. Both hardness and electrical conductivity are enhanced by annealing process. The improvement of electrical conductivity mainly comes from the reduction of grain boundaries due to the grain growth . The enhancement of hardness relates with the increment of twin boundaries, the compressive stress and the lack of dislocations after annealing process.
10.1016-j.msea.2019.138829	-1		The effects of cold rolling and low-temperature annealing on the microstructure and mechanical properties of Cu-3Ag-0.5Zr alloy prepared by gas atomization and hot isostatic pressing (HIP) were investigated. The HIPed alloy provides a fine and homogeneous microstructure for the subsequent rolling. The high density of dislocations, the large number of ultrafine grains, and the interaction between dislocations and fine precipitates (nanosized Ag and micro-sized Cu4AgZr) are responsible for the high hardness (193 HV), excellent tensile strength (654 MPa), but relatively low elongation (5.6%). Low-temperature annealing achieves a desirable combination of high strength and moderate elongation. After annealing at 350 degrees C for 2 h, the tensile strength, yield strength and elongation are 584 MPa, 534 MPa and 13%, respectively. When annealed for 8 h, the tensile strength and yield strength decrease to 558 MPa and 504 MPa, respectively, while the elongation recovers to 16.5%. The increased elongation is mainly attributed to the recovery of dislocation-accumulation ability and the slight grain growth .
10.1016-j.msea.2020.139009	15	aging; strength; conductivity; electrical conductivity; electrical; mpa; treatment; strengthening; degrees; cu-; cold; precipitation; tensile strength; tensile; iacs	In this study, Cu-0.535Cr and Cu-0.535Cr-0.1 Mg are used to research the effects of Mg on the microstructure, physical properties, and softening resistance of Cu-Cr alloy. The mechanical properties and softening resistance of Cu-Cr alloy improve by adding Mg element, whereas its conductivity slightly decreases. The hardness, electrical conductivity, tensile strength, and yield strength of Cu-Cr-Mg alloy are 170.1 HV, 77.8% IACS, 519 MPa, and 472 MPa, respectively, after cold rolling by 60% and aging at 450 degrees C for 60 min. The strengthening mechanism of the studied alloys aging at 450 degrees C for 60 min is chiefly ascribed to the Orowan precipitation and dislocation strengthening, and is slightly contributed by solid solution strengthening. The softening temperatures of Cu-0.535Cr and Cu-0.535Cr-0.1 Mg alloys are 525 degrees C and 575 degrees C, respectively. The softening of the alloys is accompanied by the growth of Cr precipitates and the occurrence of recrystallization behavior. Mg atoms diffuse from the Cr precipitates to the Cu matrix during annealing, and the Mg atoms distributed in the precipitate-matrix interface retard the growth and coarsening of Cr precipitates. The fine Cr precipitates and Mg atoms dissolved in the matrix fix the dislocation and boundary, resulting in excellent physical properties and softening resistance of Cu-Cr-Mg alloy.
10.1016-j.msea.2020.139095	-1		Ultrafine grained Cu-3Ag-xZr (x = 0.5, 1.0 wt%) alloys with high strength and good ductility were fabricated through rapid solidification in combination with cryorolling, followed by a short-time aging. The alloys after cryorolling exhibit a high strength but a relatively low ductility for the extremely high-density dislocations and large number of nano-/micro-sized particles. A significantly increased elongation is noticed with a relatively small decrease of strength in both alloys when aged at 400 degrees C for 10 min. The presence of ultrafine grains and increased density of nano-sized Ag precipitates during aging contribute to the retention of high strength . The reduction in dislocation density and the recovered ability of dislocation accumulation result in the increase of the ductility. Compared with the Cu-3Ag-0.5Zr alloy produced by casting and cryorolling combined with aging, the Cu-3Ag-xZr (x = 0.5, 1.0 wt%) alloys in this paper exhibit excellent combination of high strength and good ductility.
10.1016-j.msea.2020.139110	-1		To enhance the creep resistance at elevated temperatures, a new precipitation-strengthened CuCrNbZr alloy has been designed and fabricated to achieve a target microstructure with coarse Laves_Cr2Nb precipitates at grain boundaries and fine Cr-rich precipitates in the matrix. This work systematically studied the creep property of the CuCrNbZr alloy at 500 degrees C under 90-140 MPa applied stress and compared to that of a reference commercial CuCrZr alloy without Laves_Cr2Nb precipitates. Microstructures before and after creep testing were investigated by optical and transmission electron microscopy. Based on the creep testing and microstructural characterization results, the dominant creep mechanism in both alloys was grain boundary sliding with a threshold stress of -80 MPa. The CuCrNbZr alloy has higher creep strength and higher creep fracture ductility, and longer creep life than the CuCrZr alloy. The improved creep property in the CuCrNbZr alloy was due to the presence of Laves_Cr2Nb precipitates that efficiently impede the crack propagation.
10.1016-j.msea.2020.139345	-1		There is a significant demand for Cu-based materials with high strength and high electrical conductivity for a wide range of applications. However, the long-standing trade-off between mechanical properties and electrical conductivity often inhibits the development of such high-performance Cu materials. Cu-based metal matrix nanocomposites (MMNCs) are promising to mitigate this trade-off, but it is extremely difficult to fabricate bulk MMNCs with a uniform nanoparticle dispersion through an economical approach . In this study, a novel molten salt-assisted incorporation method was developed to fabricate bulk Cu-based nanocomposites with uniformly dispersed WC nanoparticles. The mechanical properties, including hardness, strength and Young's modulus, were significantly enhanced without a great sacrifice in electrical conductivity. Furthermore, various salts, including KAlF4, borax, and NaCl, were found effective to incorporate WC nanoparticles into molten Cu. This molten salt-assisted incorporation method paves a pathway for the scalable manufacturing of bulk Cu-based MMNCs with excellent mechanical properties and good electrical conductivity for widespread applications.
10.1016-j.msea.2020.139348	-1		Severe plastic deformation (SPD) techniques are among the most effective deformation modes of introducing a high rate and density of dislocations in metallic materials and alloys. The newly introduced dislocations have different characters. These were classified after Hansen and the Risce group as statistically stored (SSD), also called incidental dislocations (ID), and geometrically necessary (GND) dislocations. As the strain cumulates some of these dislocations, namely the GNDs, are promoted to form very-low, low, and eventually high-angle boundaries. That is, new cell and grain structured are formed as the plastic deformation accumulate. Studies of the early stages of plastic deformation inducing microstructure modifications are properly carried out on pure metals as they strengthen only by the effect of dislocation, crystallite boundaries, and texturing of the metallic matrix. On this basis, the present work focuses on an electron microscopy study of the early plastic deformation stages induced in an OFHC 99.99% pure copper by high-pressure torsion (HPT). A threshold stress for the initiation of twinning formation within the Cu-grains was identified. Nanoindentation measurements were performed at different penetration depths. Thus, a correlation between the tip size-sensitive hardness evaluation (known as indentation size effect, ISE), occurring at the lower penetration depths, and the twinning formation during the early stages of HPT was found.
10.1016-j.msea.2020.139395	16	wear; composite; composites; powders; milling; particles; powder; wt; sliding; friction; hardness; matrix; mechanical; surface; properties	Hybrid-reinforced metals are novel composite materials in which nano-phases including nanoparticles and nanotubes/nanosheets are used simultaneously to reinforce metals or alloys to enhance physical, mechanical, wear and other properties. In this research, Cu/(CNT-SiC) hybrid nanocomposite was synthesized using flake powder metallurgy and spark plasma sintering method and the effects of hybrid reinforcements on microstructural, wear and corrosion properties of the developed material were investigated and compared with those of copper. Microstructural characterization showed reduction of average grain size from 419 to 307 nm and increase of low angle grain boundaries with the introduction and homogeneous dispersion of hybrid reinforcements. Mechanical tests indicated that the addition of hybrid SiC and CNT reinforcements substantially increased microhardness and reduced wear rate and friction coefficient of the Cu. Also, polarization and EIS tests revealed the suppressing of the anodic dissolution of the matrix, hindering the oxygen reduction reaction and 62.5% improvement of corrosion rate for the composite material. The effects of hybrid nano-reinforcements are presented and discussed.
10.1016-j.msea.2020.139441	-1		Synchronous improvement of the strength and ductility for metallic materials is an everlasting object as the good service performance. In this study, the yield strength (sigma(YS)) and uniform elongation (epsilon(UE)) of Cu-Al alloys with three Al contents, nine grain sizes induced by the controlled annealing treatment, and three gradient structures induced by surface spinning strengthening (3S) treatment were explored. Results show that the sigma(YS) and epsilon(UE) may be enhanced synchronously by increasing Al content from 5Al, 8Al to 11Al, while the sigma(YS) decreases and epsilon(UE) increases when increasing grain size from ultra-fined grain, fine grain to coarse grain, and the sigma(YS) increases obviously and epsilon(UE) decreases slightly by constructing the gradient layer. The trade-off relation between strength and ductility is broken through by increasing Al content, however cannot be broken through by controlling grain size, and cannot be directly broken through by constructing gradient structure. In addition, the Cu-Al alloys with the high Al content, fine grain and gradient layers obtain the superior combination of strength and ductility, and the reason is that the solid-solution strengthening, boundary strengthening and work hardening are combined together. Inspired by these, the composition design, grain size regulation, and gradient structure construction may be considered as the three feasible approaches to enhance the strength and ductility of metallic materials.
10.1016-j.msea.2020.139619	6	grain; deformation; strain; strength; dislocation; cu-; tensile; size; ecap; grain size; sfe; ductility; hardening; high; stress	This article aims to investigate the mechanical properties of the gradient structured (GS) Cu-Al-Zn alloys. To prepare the GS samples, three kinds of Cu-Al-Zn alloys with different stacking fault energies (SFEs) were processed by surface mechanical attrition treatment (SMAT) at cryogenic temperature. The results show that the Cu-5.5%A1-4.5%Zn alloy having the lowest SFE processed by SMAT for 5 min exhibits an optimized combination of strength and ductility. For both the initial annealed sample and the SMAT samples processed for the same processing time, uniform elongation (UE) and ultimate tensile strength (UTS) increase with decreasing SFE, whereas the yield strength (YS) is not sensitive to SFE. In the case of the same SFE, as the SMAT processing time increases, the YS and UTS of the GS alloy increase and the UE decrease. The optimized SMAT processing time can sufficiently refine the grains in the GS layer, which can increase the strength and maintain good ductility. Also, sufficient grain refinement promotes the better accumulation of geometrically necessary dislocations (GNDs), thus forming rather effective hetero-deformation induced (HDI) stress strengthening and HDI hardening to enhance strength while maintaining good ductility. The combination of low SFE and optimized SMAT processing time is beneficial to obtain an optimized combination of strength and ductility. Additionally, since the near-surface layer of the GS material is plastically deformed earlier than the sub-surface layer, the accumulation of GNDs at the interface between the two layers also contributes to HDI strengthening and HDI hardening to improve strength and ductility.
10.1016-j.msea.2020.139674	-1		Ultrafine grained (UFG) Cu-NbC nanocomposites with 3.2, 6.4 and 9.5vol% in-situ formed NbC nanoparticles were fabricated by a combination of high energy mechanical milling, heat treatment and hot extrusion. The microstructure and mechanical properties of the samples were investigated to establish the NbC volume fractionme-chanical properties relationship. It is shown that 6.4vol% is the best among the three NbC volume fractions for achieving the highest tensile strength (869 MPa) and a good ductility (elongation to fracture: 6.0%) of the UFG Cu-NbC nanocomposites. The microstructural reasons for the optimum properties are analyzed.
10.1016-j.msea.2020.139687	-1		In this study, thermomechanical processing (TMP) including cold rolling and subsequent annealing was applied to a novel ti-dimensional core/shell structured (Harmonic Structure, HS) pure Cu. Detailed microstructure observation by electron backscattering diffraction (EBSD) suggested that it was possible to manipulate the volume fraction and the grain size of the core/shell via TMP. Tensile tests revealed that the mechanical properties of the HS designed pure Cu can be further optimized by appropriate TMP. For instance, the ultimate tensile strength and total elongation of the TMP30% sample (CR30%+annealing at 673 K for 1.8 ks) were 279 MPa and 51%, respectively, which were simultaneously higher than those of the original HS sample. The underlying mechanisms for the improved strength and ductility in the TMP processed samples were discussed based on the change of microstructures during cold rolling and annealing.
10.1016-j.msea.2020.139815	6	grain; deformation; strain; strength; dislocation; cu-; tensile; size; ecap; grain size; sfe; ductility; hardening; high; stress	Cryogenic high-speed rolling (C-HSR), where the specimen cooled in liquid nitrogen is supplied to rolls at rotating 1500 m/min at room temperature, was carried out with Cu x Al (x = 3.1 and 6.8 mass%) alloy to investigate mechanical properties and electrical conductivities. After 2-pass rolling, the tensile strength was 665 MPa and 841 MPa in case of Cu-3.1 mass% Al and Cu-6.8 mass% Al, meanwhile, conventional low-speed (5 m/ min) cold rolling (LSR) showed 605 MPa and 805 MPa, respectively. The balance of strength-electrical con-ductivity improved in the case of C-HSR compared to LSR. This trend was clearly observed in Cu-3.1 mass% Al. Yield strength and electrical conductivity were predicted using the modified Hall-Petch equation and modified Mayada and Shatzkes (MS) model. It is formed C-HSR increased the accumulation of dislocation density as well as decreasing mean grain size and activation of deformation twins. On the other hand, increase of dislocation density was dominant to contribute the electrical resistivity.
10.1016-j.msea.2020.139917	-1		The mechanical properties and microstructure transformation of Cu-15Ni-8Sn-xFe (x = 0, 0.1, 0.3, 0.5, wt. %) alloys prepared by vacuum induction melting were investigated by using optical microscopy (OM), atom-probe tomography (APT) and scanning transmission electron microscopy (STEM). The results showed that the addition of Fe in Cu-15Ni-85n alloy could improve the anti-aging resistance, hardness and tensile properties. Further, when the Fe content is 0.1%, the maximum hardness, ultimate tensile strength and yield strength of the alloy were 30 HV, 123 MPa and 58 MPa higher than that of the Fe-free alloy, respectively. Through APT analysis, it is found that Fe was mainly enriched at the core of the DO22 ordered phase, which probably the key factor to improve the performance. Moreover, the inhibition of the discontinuous precipitation (DP) was related to the increases in the interlamellar spacing of DP, the decrease in the solute diffusivity along the advancing boundary, and increase in the stability of the DO22 ordered phase.
10.1016-j.msea.2020.140001	15	aging; strength; conductivity; electrical conductivity; electrical; mpa; treatment; strengthening; degrees; cu-; cold; precipitation; tensile strength; tensile; iacs	A novel Cu-Cr-Yb alloy was designed and processed by thermo-mechanical treatment. The microstructure, mechanical and electrical properties were investigated in detail. The results showed that the Cu-Cr-Yb alloy had a higher strength, a better softening resistance and a considerably high electrical conductivity than the Cu-Cr alloy. After 80% cold rolling followed by aging at 500 degrees C, the peak-aged Cu-Cr-Yb alloy had a Vickers hardness of 160 +/- 1 HV, a tensile strength of 465 MPa, an elongation of 21.1% and an electrical conductivity of 89.5 %IACS, respectively. After a long-time aging at 500 degrees C, the nano-scale Cr-rich precipitates with FCC structure in the Cu-Cr-Yb alloy hardly coarsened. Thermodynamics analysis showed that the Cr-rich precipitates were inclined to nucleate with FCC structure, and the addition of Yb hindered the nucleation of the Cr-rich precipitates.
10.1016-j.msea.2020.140054	-1		The microstructure and phase-formation behavior of Cu-Sn alloys were investigated as a function of alloy composition; in addition, hot plastic deformation was performed at different cooling rates to evaluate the effect on the mechanical properties of the alloys. The microstructure of the as-cast Cu-Sn alloy consisted of a dendritic primary-alpha phase and an alpha+delta-Cu41Sn11 eutectoid phase. Hot plastic deformation performed at 750 degrees C induced a dynamic phase transformation from alpha+delta eutectoid into single bcc beta-Cu Sn-17(3). Furthermore, the removal of pore defects, refinement of phases, and work hardening were introduced into the microstructure of the Cu-Sn alloys. For samples quenched after high-temperature processing, the atomic diffusion of Sn solutes in the beta phase was suppressed due to the high cooling rate, leading to a diffusionless transformation of the beta phase into the acicular-shaped beta'-Cu5.6Sn martensitic phase. Despite severe deformation, the Cu-22 wt%Sn sample, which contained a large amount of the beta' martensitic phase, exhibited improved hardness, tensile strength, and ductility.
10.1016-j.msea.2020.140091	-1		The microstructure, precipitation kinetics, electrical conductivity, and mechanical properties of Cu-7.9 wt%Ag and Cu-5.8 wt%Ag doped with 0.6 wt%Nb were investigated. As-cast microstructure revealed both discontinuous and continuous precipitation of Ag in Cu matrix. Differential scanning calorimetry data indicated that continuous precipitation occurred at higher temperatures with higher activation energy. Both micro-sized and nano-sized Nb particles were observed in the Nb-doped Cu-Ag alloy. The doping of Nb significantly suppressed the growth of discontinuous Ag precipitates and consequently increased the activation energy and the volume fraction of continuous Ag precipitates. Because of larger volume fraction of finer-spaced continuous Ag precipitates, the Nb-doped alloy showed higher hardness and strength than the un-doped Cu-Ag. After cold-rolling, the strength of the Nb-doped alloy remained higher than that of the un-doped Cu-Ag.
10.1016-j.msea.2020.140120	15	aging; strength; conductivity; electrical conductivity; electrical; mpa; treatment; strengthening; degrees; cu-; cold; precipitation; tensile strength; tensile; iacs	The changes in the yield strength and electrical conductivity of a Cu-Cr-Ti-Si alloy strip after rolling at room temperature, annealing at 370 degrees C, and annealing at 420 degrees C were investigated. The influence mechanism of the annealing temperature on the microstructure, such as the texture characteristics and dislocation density, was revealed. The results show that compared with the room-temperature rolled state, low-temperature annealing temperature has a significant effect on the mechanical properties and microstructures of the Cu-Cr-Ti-Si alloy strip. After annealing at 370 degrees C, the yield strength and ultimate tensile strength reach 525 MPa and 544 MPa, respectively. The hardness and electrical conductivity reach 164.5 HV and 84.6% IACS, respectively. In addition, the microstructure of the alloy annealing at 370 degrees C exhibits a higher dislocation density and a higher texture intensity compared to the sample rolled at room temperature. The results provide theoretical guidance for optimization of the heat treatment process of high-precision Cu-Cr-Ti-Si alloy strips.
10.1016-j.msea.2020.140144	-1		Cu-Cr and Cu-Cr-Mg alloys were prepared to determine the stress relaxation mechanism and the effect of Mg on the stress relaxation resistance of Cu-Cr alloys by analyzing the microstructure, morphological characteristics of the precipitates and dislocation densities before and after the stress relaxation test using electron backscatter diffraction (EBSD), transmission electron microscopy (TEM) and X-ray diffraction (XRD). The formation of Cottrell atmospheres in the Cu-Cr-Mg was verified by theoretical calculations and the serrations in the stress-strain curves; thus, the way that Mg improved the stress relaxation resistance of the Cu-Cr alloy was identified. The stress decreased rapidly at first, dropped slowly and then gradually stabilized during the stress relaxation of the two alloys. The kinetic equations of both alloys were obtained. The stress relaxation behavior was very sensitive to the temperature, and an increase in the temperature accelerated the rate of stress reduction. Recrystallization and a decrease in the dislocation density were accompanied by the stress relaxation of both alloys, but the changes in the morphological characteristics of the precipitates were negligible. The recrystallization was the main factor behind the stress relaxation of both alloys. Mg obviously improved the stress relaxation resistance of the Cu-Cr alloy. There were no Cottrell atmospheres at room temperature, and the Mg and mobile dislocations formed Cottrell atmospheres only at 100 degrees C and above. The increase in the stress relaxation resistance of the Cu-Cr-Mg alloy was attributed to the interactions among the fine grains, precipitates, Mg atoms and dislocations.
10.1016-j.msea.2020.140148	15	aging; strength; conductivity; electrical conductivity; electrical; mpa; treatment; strengthening; degrees; cu-; cold; precipitation; tensile strength; tensile; iacs	Developing Cu-Ni-Si alloy with high strength and high electrical conductivity is a key issue in the electrical conductor industries. The C70250 copper alloy was prepared by two-phase zone continuous casting (TZCC) technology first, and then carried out by double cold rolling-aging process. The relationship between different double cold rolling-aging processes, microstructure, mechanical properties and electrical conductivity of the alloy was studied in detail, the mechanism was revealed. The results show that the C70250 copper alloy strip fabricated by TZCC technology can be subjected to large deformation double cold rolling-aging treatment. When the alloy is primary cold rolled by 97.5% reduction rate, primary aged at 400 degrees C for 30 min, second cold rolled by 60% reduction rate, second aged at 400 degrees C for 45 min, the tensile strength and electrical conductivity of the alloy can reach 879 MPa and 48.9% IACS respectively, owning excellent comprehensive properties. The Ni2Si phases inside C70250 copper alloy after primary aging effectively pin dislocations during the secondary cold rolling process, which forms high density dislocation entanglement, promotes the further precipitation of Ni2Si phase during the process of secondary aging, and finally produces a large number of fine, dispersed, multi-scale mixed and evenly distributed Ni2Si phases, the increase of alloy strength is mainly ascribed to dislocation and Orowan strengthening effect. Solute atoms inside the C70250 copper alloy get adequately precipitated after large deformation double cold rolling-aging treatment, the recrystallization is delayed, and the fibrous microstructure along the rolling direction is produced, the scattering effect of transverse grain boundaries and solute atoms on electrons is significantly reduced, which is helpful to improve the electrical conductivity of the C70250 copper alloy.
10.1016-j.msea.2020.140161	-1		In this study, a novel dispersion-strengthened copper-tungsten alloy with improved mechanical properties, electrical conductivity, and thermal stability was prepared by mechanical alloying. Cu-WO3 powder blend was milled to obtain a uniform dispersion of WO3 in copper and the WO3 particles were subsequently reduced to tungsten to obtain the Cu-W composite. The tungsten nanoparticles dispersed in the copper matrix have an average size of 32 nm, without agglomeration, and are highly stable. The cold-rolled Cu-5 vol% W reached a tensile strength of 596 MPa, elongation of 7.7%, and electrical conductivity of 84% IACS (International annealing copper standard). In particular, the cold-rolled alloy retains the tensile strength of over 400 MPa and reasonable ductility even after annealing at 800 degrees C. The remarkable improvement in mechanical properties and thermal stability are attributed to the pinning effect of highly dispersed nano-sized W particles in the Cu matrix.
10.1016-j.msea.2020.140198	-1		Rapidly solidified (RS) Cu-3Ag-0.5Zr alloy was prepared by hot isostatic pressing (HIP) and hot forging with rapid solidified alloy powder. Hot isothermal compressive deformation was conducted at room and elevated temperatures (400-900 degrees C) with a stable strain rate of 0.001/s. The mechanical properties and microstructure of alloy before compression and compression at different temperatures (400-900 degrees C) were investigated. The results show that the original Cu-3Ag-0.5Zr alloy has a 520 MPa compressive strength at room temperature, which is related to the small grain size (about 2 mu m) of RS alloy and the interaction between second phases (Cu4AgZr, Ag particles) and dislocations. Compression at elevated temperatures (400-900 degrees C) will rise strength decreasing continuously and the compressive strength is just 23 MPa, specially Portevin Le-Chateliers (PLC) effect is observed after 700 degrees C, both of which results from the microstructure evolution of alloy at elevated temperatures. That the Ag particles will aggregate and grow up and dynamic recrystallization (DRX) is found at elevated temperatures. The two processes were both accelerated at higher temperature, which make the interaction between secondary phases and dislocations decreasing and finally the strength decreases. Portevin Le-Chateliers (PLC) effect is a result of intense interaction between DRX and plastic deformation. In addition, the discontinuous dynamic recrystallization (DDRX) and continuous dynamic recrystallization (CDRX) occur simultaneously during compression at elevated temperatures.
10.1016-j.msea.2020.140275	-1		In this study, we achieved hetero-structuring of multi-phase (CuFe)(100-x)Mn-x (x = 15, 20, and 33 at%) medium -entropy alloys having excellent strength-ductility synergy by systematic investigation of microstructural and mechanical responses. The significant hetero-deformation-induced strengthening of the alloys is attributed to the high plastic incompatibility between Cu-rich and Fe-rich phases from thermallyand deformation-induced martensitic phase transformation.
10.1016-j.msea.2020.140379	15	aging; strength; conductivity; electrical conductivity; electrical; mpa; treatment; strengthening; degrees; cu-; cold; precipitation; tensile strength; tensile; iacs	In order to shorten the production process of Cu-Fe alloy and improve the microstructure homogeneity and properties and properties, Cu-10 wt%Fe alloy billet was prepared by double-melt mixed casting process and then cold rolled. Microstructure and mechanical property evolutions of the alloy and its deformation behaviours were investigated. The results showed that the alloy billet had dispersed spherical Fe phase particles and dendritic Fe phases. The alloy billet had excellent plasticity, and the cumulative cold rolling reduction without intermediate annealing reached 98%. When the reduction was 30%, numerous dislocations produced in the Cu matrix and the Cu matrix near the Fe phase underwent local crystal rotation, and the Fe phase particles deformed slightly. When the reduction exceeded 90%, dynamical recrystallization of the Cu matrix happened, fine grains with average diameter of similar to 300 nm formed, and the dendritic Fe phases were evenly distributed along the rolling direction, which mainly contributed to achieve large-reduction of cold rolling. When the reduction was 98%, the tensile strength and hardness increased from 340 MPa and 87 HV of the as-cast alloy to 543 MPa and 164 HV, respectively, and the elongation and electrical conductivity was reduced to 3.0% and 13.5%IACS. A process of double-melt mixed casting -> cold rolling can work as a novel high-efficiency and compact method to produce Cu-Fe alloy sheet.
10.1016-j.msea.2020.140413	15	aging; strength; conductivity; electrical conductivity; electrical; mpa; treatment; strengthening; degrees; cu-; cold; precipitation; tensile strength; tensile; iacs	The relationship between rolling-aging sequence and the microstructure evolution, mechanical-electrical properties of hot rolled-quenched Cu-0.67Cr-0.27Zr-0.12Ni-0.03Si-0.04Ti alloy was investigated in details and the underlying mechanism of the abnormal decrease in electrical conductivity of the peak-aged alloy by cold rolling was also revealed. The results indicated that a good combination of the tensile strength (585.5 MPa), yield strength (562.1 MPa), Vickers hardness (197.6 HV), and electrical conductivity (67.4 %IACS) was obtained in the Cu-Cr-Zr-based alloy by a sequence of peak aging at 450 degrees C for 2 h followed by 80% room-temperature rolling and then secondary aging at 400 degrees C for 1 h . Compared with the rolling-aging process, the strength improvement of the alloy by the aging-rolling-aging process was mainly dominated by dislocation density strengthening. Additionally, a decrease in electrical conductivity of the peak-aged alloy after cold rolling was attributed to the re-dissolution and the refinement of partial coherent precipitates.
10.1016-j.msea.2020.140472	-1		Owing to its excellent wear resistance and good mechanical properties, the sintered Cu-Al-Ni alloy is an ideal material for preparing sliding bearings and self-lubricating sleeves. Adding trace elements into the Cu-Al-Ni alloy is expected to further enhance these properties. Hence, in this work, the microstructure and properties of sintered Cu-12 Al-6 Ni alloys with varying contents of added Ti are studied. Results indicated that the NiAl, gamma(2), and alpha phases were distinctly refined when the Ti addition was 0.2 wt%, and a small amount of the granular X phase ((Cu, Ni)(2)AlTi) appeared in the alloy. The X phase increased and coarsened with increasing Ti addition. When the Ti addition was 0.7 wt%, pores appeared in the center of the large granular X phase. With increasing Ti addition, the sintered density of the alloys gradually decreased, while the hardness and tensile strength increased first and then decreased. When the Ti addition was 0.7 wt%, the hardness reached the maximum (160 HB), while when the Ti addition was 0.2 wt%, the tensile strength reached the maximum (412.2 MPa). Moreover, the friction coefficient and wear loss of the alloy were the lowest when the Ti addition was 0.2 wt%. These findings can provide some theoretical guidance for fabricating high-performance Cu-Al-Ni powder alloys.
10.1016-j.msea.2020.140510	15	aging; strength; conductivity; electrical conductivity; electrical; mpa; treatment; strengthening; degrees; cu-; cold; precipitation; tensile strength; tensile; iacs	A Cu-Ti-Cr-Mg-Si alloy with the super-high strength and high electrical conductivity was designed, and the effects of multi-stage thermomechanical treatment on the microstructure and properties of the alloy were investigated. The alloy treated by the multi-stage thermomechanical treatment had a yield strength of 1072 MPa, tensile strength of 1144 MPa, elongation of 6.1% and electrical conductivity of 24.1 %IACS. During the thermomechanical treatment, the nanoscale beta'-Cu4Ti particles, Cr precipitates and submicro-particles that mainly consisted of Cu, Ti, Cr and Si elements formed, leading to the high strength of the alloy. beta'-Cu4Ti phase with body-centered tetragonal structure had a classic orientation relationship with copper matrix: [001]Cu//[001]beta' and [3-10]Cu//[100]beta'. The super-high strength of the designed alloy was mainly attributed to the precipitation strengthening, sub-structure strengthening, solid solution strengthening and work hardening. Electrical conductivity increased during aging due to the decomposition of supersaturated solid solution. Compared with direct aging treatment, multi-stage thermomechanical treatment with the stepped temperature-reduction further improved the mechanical and electrical properties of the alloy.
10.1016-j.msea.2020.140521	15	aging; strength; conductivity; electrical conductivity; electrical; mpa; treatment; strengthening; degrees; cu-; cold; precipitation; tensile strength; tensile; iacs	High strength and high electrical conductivity Cu-Cr-based alloys are important candidate materials for preparing lead frames, railway contact wires and connects. However, high strength and high electrical conductivity are mutually exclusive in nature. To optimize the mechanical and electrical properties of a Cu-Cr-Ni-Si alloy, the two-step cryorolling and aging (CRA) was carried out in this study. Here, by the analysis of microstructure evolution, precipitation behavior, and corresponding strengthening mechanisms of the alloy at different rolling and aging conditions, we find that the yield strength and electrical conductivity for the two-step CRA sample are improved by 91.3 MPa and 4.9 %IACS (International Annealed Copper Standard) than those of the sample subjected to single-step room temperature rolling and aging (RTRA). The higher yield strength for the two-step CRA sample is mainly determined by the precipitation strengthening contributed from Ni2Si and Cr precipitates, rather than the twin boundary strengthening and dislocation strengthening. In fact, the dislocation density of the two-step CRA sample is lower than that of the single-step RTRA sample because of the faster drop rate of recovery, which weakens the effect of dislocation strengthening. The combination of the first-step aging and second-step CR process for the two-step CRA sample contributes to the formation of more precipitates from the matrix, thereby significantly increasing the precipitation strengthening and decreasing the impurity scattering in the final aging. The results provide a new preparation process and a reliable theoretical approach for optimizing the mechanical and electrical properties of the Cu-Cr alloys.
10.1016-j.msea.2020.140580	6	grain; deformation; strain; strength; dislocation; cu-; tensile; size; ecap; grain size; sfe; ductility; hardening; high; stress	It has often been observed that solute hydrogen triggers a remarkable increase in flow stress in pure Ni. As reported in previous studies, this H-induced hardening has been attributed to the solid-solution strengthening and/or H-enhanced evolution of the dislocation structure. However, it remains unclear which of those two factors actually dominates such macroscopic hardening-behavior. Via two mechanical tests at different scales, i. e., slow strain-rate tensile (SSRT) and micro Vickers hardness (MVH) tests, the H-enhanced evolution of the dislocation structure and its contribution to H-induced hardening in pure Ni and in Cu-Ni alloy were investigated in this study. In pure Ni, the SSRT test at room temperature (RT) demonstrated an increase in flow stress with a greater work-hardening rate, indicating the H-enhanced evolution of the dislocation structure, as supported by the MVH test. Nevertheless, the SSRT and MVH tests revealed that the H-enhanced evolution of the dislocation structure was significantly suppressed at 77 K. On the other hand, with respect to Cu-Ni alloy, no H-enhanced evolution of dislocation structure was observed during the SSRT and MVH tests, regardless of the deformation temperatures. This difference in the evolution of the dislocation structure between pure Ni and Cu-Ni alloy was consistent with the experimental results obtained beforehand, using scanning transmission electron microscopy (STEM). A series of experimental results indicated that both the solid-solution strengthening and H-enhanced evolution of the dislocation structure could contribute to the increase in flow stress, with the degree of contribution dependent on the respective material and the deformation temperature.
10.1016-j.msea.2020.140598	15	aging; strength; conductivity; electrical conductivity; electrical; mpa; treatment; strengthening; degrees; cu-; cold; precipitation; tensile strength; tensile; iacs	The effect of aging treatment on the microstructure of Cu-Cr-Ti alloy was studied by Scanning electron microscope (SEM) and Transmission electron microscope (TEM), and its electrical conductivity, microhardness and tensile strength were also measured. The results showed that the Cu-Cr-Ti alloy had a microhardness of 166 H V, tensile strength of 551 MPa and electrical conductivity of 78.2%IACS after being solution treated at 960 degrees C, 80% cold rolled and aged at 500 degrees C for 1 h . TEM characterization revealed that the precipitates were fully coherent with copper matrix after aging at 450 degrees C for 1 h . Two precipitates of face-centered cubic (fcc) and body-centered cubic (bcc) Cr structures existed in the matrix at the same time after aging at 500 degrees C for 1 h, and the existence of ordered phases accelerated the transformation from fcc to bcc. After aging at 550 degrees C for 1 h, the relationship between precipitates and the matrix transformed into a semi-coherent relationship, and the strength gradually deteriorated.
10.1016-j.msea.2020.140628	15	aging; strength; conductivity; electrical conductivity; electrical; mpa; treatment; strengthening; degrees; cu-; cold; precipitation; tensile strength; tensile; iacs	The effect of micro-alloying elements of Cr and Sn on microstructures, mechanical-electrical properties and softening resistance of the novel Cu-Cr-Sn alloys were investigated in details by transmission electron microscopy (TEM), atom probe tomography (APT), electron backscatter diffraction (EBSD) and X-ray diffraction (XRD). The results showed that the tensile strength, yield strength, microhardness and electrical conductivity of Cu-0.67Cr-0.23Sn alloy by 80% cold-rolling and aging at 400 degrees C for 2 h can reach 566.3 MPa, 527.6 MPa, 186.2 HV and 73.3 %IACS, respectively. The TEM and APT analysis indicated Sn addition can promote the precipitation of Cr phase and inhibit the coarsening of Cr precipitates, thus improving the strength of Cu-Cr-Sn alloy. The precipitation strengthening was the dominant mechanism for improving the yield strength of Cu-Cr-Sn alloys. Besides, the designed Cu-Cr-Sn alloys exhibited a high softening temperature since the addition of Sn inhibited the coarsening of Cr precipitates and delayed the recrystallization of deformed structure.
10.1016-j.msea.2020.140659	-1		Cu25Fe75 and Cu50Fe50 (nominal composition, at. %) alloys were fabricated using laser direct metal deposition (DMD) based additive manufacturing technique. These alloys exhibit hierarchical microstructures with bi-phasic Cu and Fe dendrites that contain nanoscale precipitates of varying sizes and structures. In the Cu25Fe75 alloy, Fe dendrites contained nanoscale, coherent, metastable BCC Cu and semi-coherent FCC Cu precipitates while the Cu matrix had nanoscale, coherent, metastable FCC Fe precipitates. In the Cu50Fe50 alloy, Fe dendrites only contained nanoscale semi-coherent FCC Cu precipitates while the Cu matrix had nanoscale coherent metastable FCC Fe precipitates. Both alloys exhibited enhanced flow strengths in the range of 750-980 MPa and significant plasticity, in compression. The Cu25Fe75 alloy had lower yield strength than Cu50Fe50 alloy but higher maximum compressive strength due to higher strain hardening resulting from slightly coarser dendrites with hierarchy of nanoscale precipitation.
10.1016-j.msea.2020.140666	-1		In the current research, the effect of post-annealing treatment at 200 degrees C with four different holding times of 5, 10, 30, and 60 min on the asymmetrically cold-rolled pure copper was investigated. The microstructural evolution (via optical microscopy and scanning electron microscopy), mechanical properties (by tensile and hardness tests), and electrical conductivity of the post heat-treated copper sheets were evaluated. The static recrystallization (SRX) took place at a short annealing time due to the large strain stored energy caused by the asymmetric cold rolling as well as the presence of particles. The average grain size of the post-annealed sample for 5 min was about 96 nm. The copper after 60 min post-annealing consisted of many coarse polygonal grains, a few small grains, and multiple twinning (twin chains). The formation of multiple twinning and twin chains was due to the low-temperature annealing (200 degrees C) of rolled copper. The tensile properties indicated that the strength had a relatively low sensitivity to the increment of annealing time and the produced pure copper exhibited superior thermal stability. The formation of twin chains and the existence of copper oxide particles were responsible for this unusual behavior. The copper annealed for 60 min had a low YS-to-UTS ratio (0.378) and a high work hardening rate, which were equivalent to high formability. For the low annealing times of 5 and 10 min, there were both shear and equiaxed dimples on the fracture surface indicating a combination of ductile shear and ductile fractures. When the time of post-annealing was higher than 30 min, only the ductile dimples could be observed on the fracture surface. The post-annealing treatment for 60 min increased the electrical conductivity to from 84.10 to 87.52 %IACS due to the occurrence of recovery, recrystallization, and grain growth . Finally, it was found that adopting a high enough pre-deformation (96% strain) and a suitable annealing time (60 min) at a low annealing temperature (200 degrees C) in the pure copper could make a good balance between tensile and electrical properties.
10.1016-j.msea.2020.140716	6	grain; deformation; strain; strength; dislocation; cu-; tensile; size; ecap; grain size; sfe; ductility; hardening; high; stress	The effect of alloying elements on microstructural evolution during the formation of ultrafine grained (UFG) structures in fcc materials during equal channel angular pressing (ECAP) was investigated. This research focused on the relative influence of stacking fault energy (SFE) and solid solution effect by comparing Cu, Ag and Cu-Al alloys (Cu-4.6 at%Al and Cu-6.8 at%Al). Either the dislocation cell or grain sizes were found to decrease together with a significant accumulation of dislocations during the early stage of successive passes in materials having low SFEs. These changes occurred regardless of the presence of solute atoms. In contrast, the solid solution effect resulted in delayed saturation of the dislocation density and hardening in the later stage of deformation, at which point the formation of a UFG structure was almost complete. The grain size after eight passes decreased with decreasing SFE, following a power law relationship. However, the effect of solute atoms on grain size reduction increased at greater plastic strain values because of steady, ongoing microstructural evolution and hardening resulting from the solid solution effect.
10.1016-j.msea.2021.140906	10	composites; nanoparticles; strength; matrix; high; strengthening; particles; conductivity; composite; electrical; mpa; sintering; ods; grains; mechanical	Here an ideal grain structure, with short dislocation-slip path and low dislocation density, is fabricated in a Cu-Al alloy by combining equal channel angular pressing and cold rolling at liquid nitrogen temperature and subsequent annealing at 350 degrees C. The microstructure of this ideal structure is characterized by fine recrystallized grains in size of a few micrometers with abundant nanotwins and high angle grain boundaries. Accordingly, a good strength-ductility synergy combining a yield strength of 475 MPa and a uniform elongation of about 27.9% is obtained in tensile test. The transmission electron microscopy (TEM) examinations revealed effective hindering of dislocations by twin boundaries and storage of dislocations inside grains, which are responsible for the excellent strain hardening capability. This study provides a promising grain structure for industrial application.
10.1016-j.msea.2021.141064	15	aging; strength; conductivity; electrical conductivity; electrical; mpa; treatment; strengthening; degrees; cu-; cold; precipitation; tensile strength; tensile; iacs	The microstructure and properties of the Cu-6.5Fe-xMg (x = 0, 0.1, 0.3, 0.5 wt%) alloy were investigated by TEM (transmission electron microscopy), EBSD (electron backscattered diffraction) and tensile testing machines to explore the effect of Mg addition on Fe phase morphology, aging kinetics and properties of Cu-6.5Fe alloy. The properties testing discovered that the addition of Mg significantly improved the tensile strength of Cu-6.5Fe alloy but slightly reduced its conductivity. The tensile strength and conductivity of Cu-6.5Fe-0.3 Mg alloy were 704 MPa and 60.2 %IACS, respectively, after aging 300 degrees C for 1 h . Compared with Cu-6.5Fe alloy, the tensile strength of Cu-6.5Fe-0.3 Mg alloy increased by approximately 236 MPa, and the conductivity decreased by only 1.9 % IACS. The microstructure observation showed that the addition of Mg significantly refined the Fe phase and inhibited its dendrite segregation. After large strain plastic deformation, the granular Fe phases transformed into Fe fibers and the Fe fibers distributed denser with the addition of Mg. Furthermore, the addition of Mg promoted the precipitation of the Fe phase and effectively inhibited the recrystallization of the Cu matrix during the aging. The recrystallization of Fe phase and coarsening of the precipitated Fe phase were also inhibited. The evolution mechanism of Fe phase during casting, plastic deformation and aging in Cu-6.5Fe-0.3 Mg alloy is proposed.
10.1016-j.msea.2021.141066	-1		The Cu-Fe laminated sheets with various number of layers were produced by the accumulative roll bonding process, and the effects of the number of layers on the microstructure and low-temperature tensile properties of the sheets were elucidated. Then the reason for the excellent low-temperature tensile properties in dual-phase materials of Cu and Fe was discussed. The tensile properties of the pure Cu and Fe sheets used for fabricating the Cu-Fe laminated sheets exhibited the typical temperature dependence seen in the case of face-centered cubic (fcc) and body-centered cubic (bcc) metals. The layered structure of the laminated sheets was maintained till the number of layers was 100 but broke in the case of the 1000-layer sheet, which showed a network-like structure. The electrical conductivity of the sheets was independent of the number of layers and significantly higher than that of a Cu-Fe alloy, indicating that Fe had neither dissolved nor precipitated in the Cu layers of the laminated sheets. In the case of the 50-, 100- and 1000-layer sheet, the strength increased with lowering the temperature, while its elongation remained constant. A facet fracture surface was observed until the number of layers was 7, while in the case of the sheets consisting of more than 50-layers, fine dimples were observed on the fracture surfaces of both layers, indicating that ductile fracturing occurred. The strain in the Cu layers around the strain concentration sites of the Fe layers was high in the 50-layer laminated sheet when it was subjected to tensile deformation at 77 K. The strain concentration in the Fe layers might be accommodated by the surrounding soft Cu layers, resulting in the suppression of the nucleation of cleavage cracks in the Fe layers. This should be one of the reasons that the Cu-Fe layered sheets exhibited excellent elongation at low temperatures. Thus, the Cu-Fe layered structure take an important role for the excellent low-temperature tensile properties in the fcc and bcc dual-phase materials.
10.1016-j.msea.2021.141154	6	grain; deformation; strain; strength; dislocation; cu-; tensile; size; ecap; grain size; sfe; ductility; hardening; high; stress	Processing at cryogenic temperatures is one of the ways of improving mechanical properties of copper alloys. However, such processing routes may result in unstable microstructures, which make it difficult to understand the deformation mechanisms controlling microstructure evolution during cryogenic deformation. In this study, the microstructure evolution of a Cu-0.7Cr-0.07Zr alloy was analyzed as a function of the flow behavior during tensile tests performed at 123 K and 298 K, through in-situ X-ray diffraction (XRD) experiments in a synchrotron source. The tensile behavior was analyzed in terms of the dynamic recovery rate using the Kocks-Mecking model, while the evolution of stacking-fault density, dislocation density and crystallite size during the tests was estimated by the modified Williamson-Hall method. Solution-treated and peak-aged conditions were tested to assess the influence of particles distribution. At 298 K, the strain-hardening rate was controlled by dislocation glide and the flow stress was affected mainly by particle strengthening. At 123 K, a simultaneous increase in strength and ductility was attributed to the twinning induced plasticity (TWIP) effect, promoted by precipitate interfaces acting as nuclei for stacking-faults, thus delaying necking and increasing the plasticity. Based on the evolution of dislocation and stacking-fault densities with increasing plastic strain, it was concluded that, at 123 K, mechanical twinning predominated at strain levels below 0.15, mainly for aged conditions, while dislocation glide between twin boundaries, and its accumulation, started after TWIP mechanism reached its saturation.
10.1016-j.msea.2021.141239	15	aging; strength; conductivity; electrical conductivity; electrical; mpa; treatment; strengthening; degrees; cu-; cold; precipitation; tensile strength; tensile; iacs	The relationship between the microstructure and properties of the different orientations of a Cu?Ni?Si?Co alloy was investigated by tensile testing, X-ray diffraction electron backscattering diffraction, transmission electron microscopy, and high-energy X-ray diffraction (HEXRD). The results revealed that the cold-rolled alloy contained mainly a Brass {110} 112 211 texture. The alloy was aged, and it exhibited mainly an R texture, and its volume and distributing width were 45.2% and 10.8?, respectively. The aged alloy exhibited obvious anisotropy, and its tensile strength and electrical conductivity in the rolling direction were 870 MPa and 50% IACS, respectively. In the Cu?Ni?Si?Co alloy, the orientation grains close to the [111] crystal plane were in the hard orientation zone, the Schmid factor value was low, and the material strength was relatively high . At the same time, the [111] crystal plane was close-packed and exhibited good conductivity. The oriented grains close to the [100] crystal plane was in the soft oriented zone and had lower strength and conductivity. Through HEXRD analysis, it was found that the oriented grains with a high twin stacking-fault probability had lower stacking fault energy, and the probability of aging-induced twinning was high .
10.1016-j.msea.2021.141242	-1		Cold spray deposition involves a unique combination of high strain rate and moderate to high strain deformation of powder particles that contrasts it from conventional severe plastic deformation techniques. In the present work, a systematic study of the microstructure and micromechanical properties of cold sprayed Cu and Cu?Al alloys, which are known for significant variation in stacking fault energy with small alloying addition, is presented. The deposition process results in significant grain refinement (<50 nm) and profuse deformation twinning with very fine twins (<20 nm) in the Cu?Al alloys. The theoretical predictions of the extent of grain refinement using a dislocation-based model agree well with the experimental observations for the alloys, even in the presence of significant twinning. The inherent discrete nature of the cold spray coating deposition results in significant heterogeneity and hence extensive hardness mapping has been performed to establish structureproperty correlations at the micrometer length scale. Furthermore, the various factors influencing the hardness of the coatings are analytically determined and it was found that the strengthening contribution from the boundary (grain/twin) is much lower than that determined from Hall-Petch type relationship in case of the alloys that showed significant twinning. A twin mediated deformation mechanism in the presence of fine twins, which subsequently de-twin, is found to explain the lower boundary strengthening.
10.1016-j.msea.2021.141274	10	composites; nanoparticles; strength; matrix; high; strengthening; particles; conductivity; composite; electrical; mpa; sintering; ods; grains; mechanical	Cu composites strengthened through carbide nanoparticle dispersions (CDS-Cu) usually present a problematic agglomeration of nanoparticles that deteriorate their mechanical properties. To address this issue, in this study, CDS-Cu composites were prepared via spark plasma sintering (SPS) of reduced Cu-coated WC core-shell precursor powders, which were obtained through intermittent electrodeposition. This novel preparation method overcomes the aggregation problem of tungsten carbide (WC) nanoparticles, thereby improving the interfacebonding strength between the reinforcing-phase WC nanoparticles and the Cu matrix and further enhancing the load-transfer efficiency. The yield strength of the Cu-2.1 wt% WC composite prepared via pressureless sintering is up to 243 +/- 3 MPa, which is significantly higher than that of pure Cu (130 MPa). Orowan strengthening and grain refinement strengthening induced by dispersed nano-WC particles are the main strengthening mechanisms. Due to the load-transfer strengthening, the yield strength of the SPS composite is improved to 271 +/- 2 MPa. After hot rolling, the yield strength is further increased to 315 +/- 2 MPa, owing to the additional contribution of dislocation strengthening originating from the plastic deformation process. The proposed method in this study provides an advanced pathway for the preparation of ceramic nanoparticle dispersion-strengthened metals.
10.1016-j.msea.2021.141438	-1		Copper alloys are promising heat sink materials in future fusion reactors owing to the high thermal conductivity and good mechanical properties at medium temperatures. In the present study, aiming at enhancing the strength of copper while keeping the high thermal conductivity, nanoscale W particle dispersion strengthened Cu alloys with different W content of 2 at% (2.6 vol%), 5 at% (6.5 vol%) and 8 at% (10.3 vol%) were fabricated through ball-milling and spark plasma sintering (SPS). The effects of nanoscale W particles on the microstructure, mechanical properties and thermal conductivity of the Cu-W alloys were investigated. The average size of tungsten particles dispersed in copper matrix is 43 nm. The dispersion of W nanoparticles in copper could significantly refine the grain and improve the strength of Cu alloys. The average grain size of Cu-2at%W, Cu-5at%W and Cu8at%W is as small as 0.84 mu m, 0.65 mu m and 0.54 mu m, respectively. The tensile strength of Cu-8at%W reaches 495 MPa and the elongation is 10.6% at room temperature. The grain size refinement of Cu-W alloys can be attributed to the pinning effects of nanoscale W particles dispersed in the Cu matrix. Although the addition of W nanoparticles leads to a decrease in thermal conductivity, the thermal conductivity for all Cu-W samples is still above 300 Wm-1K-1 at room temperature.
10.1016-j.msea.2021.141464	15	aging; strength; conductivity; electrical conductivity; electrical; mpa; treatment; strengthening; degrees; cu-; cold; precipitation; tensile strength; tensile; iacs	Effects on microstructure evolution, mechanical and electrical properties of a Cu-Cr-Zr-Ni-Si-Ti alloy via multistage rolling and aging were investigated in details. The results showed that the optimal comprehensive performance of tensile strength (649 MPa) and electrical conductivity (65.5 %IACS) was obtained by three-stage rolling and aging (primary 80% room-temperature rolling (RTR) and aging at 450 degrees C for 2 h + secondary 60%RTR and aging at 300 degrees C for 1 h + tertiary 50%RTR and at 150 degrees;C aging for 1 h). Through the microstructure characterization, it was found that the orientation relationship between the precipitates and Cu matrix was (001)Cu //(001)Cr //(001)Ni2Si, [011]Cu //[011]Cr //[010]Ni2Si in the investigated Cu-Cr-Zr-Ni-Si-Ti alloy. The increase of yield strength was primarily attributed to fine grain strengthening and precipitation strengthening, and secondly attributed to dislocation strengthening. This work will provide a guideline for the fabrication of high-performance copper alloys.
10.1016-j.msea.2021.141509	-1		In-situ neutron diffraction measurements were performed on a cold-rolled copper-iron (Cu-Fe) alloy during tensile tests at 293 K and 150 K. The alloy was composed of face-centered cubic Cu and body-centered cubic Fe. The roles of Cu and Fe on the deformation behavior of alloys were discussed and clarified. The strength and work-hardening rate of the alloy increased with decreasing test temperature. Furthermore, the phase stress of Fe increased considerably with decreasing test temperature; however, the response of this stress to the applied true stress exhibited no dependence on the temperature. The phase stresses of Cu changed only slightly with decreasing test temperature. However, the Cu phase stress response to the applied true stress increased with decreasing test temperature, indicating an increase in the work-hardening rate. The strengthening of Fe and the increase in the work-hardening of Cu contributed to an increase in the strength and work-hardening rate of the Cu-Fe alloy at low temperatures.
10.1016-j.msea.2021.141521	-1		A new Cu-2 wt% Ag-0.15 wt% La alloy composed of large-size Ag-rich primary phases was processed into wire billets by successive drawing, annealing and continuous extrusion forming (CONFORM). The microstructural evolution and mechanical properties of the samples obtained by drawing, annealing and CONFORM were then investigated. The results indicate that a desirable combination of high ultimate tensile strength (300 MPa) and elongation (49.5%) was obtained after CONFORM. The latter allowed the microstructure to be significantly refined via an almost full dynamic recrystallization (DRX), with grain sizes of similar to 1 mu m. In addition, the large-size primary phases were broken into dispersed nanophases with an average size of 800 nm. The dispersed phases promoted the DRX of the matrix via particle-stimulated nucleation. As a result, the enhanced toughness (11145.98 MPa.%) is contributed by grain refinement and dispersion strengthening of the nanosized phases.
10.1016-j.msea.2021.141548	-1		The mechanical and electrical properties of continuously cast Cu-0.4 wt%Te alloy produced by continuous extrusion forming at 800 degrees C were investigated. It was found that this thermomechanical processing was an effective way to induce the formation of refined recrystallized grain and promote dynamic precipitation of Te atom, thereby simultaneously improving the strength, ductility and electrical conductivity of Cu-0.4 wt%Te alloy.
10.1016-j.msea.2021.141581	15	aging; strength; conductivity; electrical conductivity; electrical; mpa; treatment; strengthening; degrees; cu-; cold; precipitation; tensile strength; tensile; iacs	Modern electronics components require copper alloys to have higher strength and ductility for processing and forming. Cu-Ti alloys exhibit excellent mechanical properties while their plasticity is limited. In this work, high ductility Cu-Ti alloys were fabricated and investigated systematically, results indicated that the samples' strength and plasticity can be improved by adding high Ti and Cr content. The crystal relationship between the beta'-Cu4Ti and Cu is that: [100] (Cu)//[011] (beta'-Cu4Ti), (020) (Cu)//(2 (1) over bar1) (beta'-Cu4Ti). Further increase aging time, metastable beta'-Cu4Ti particles started cellular reaction to be beta-Cu3Ti phase, which were detected at the grain boundary. The crystal relationship between the beta-Cu3Ti and Cu is that: [100] (Cu)//[011] (beta-Cu3Ti,) (220) (Cu)//(400) (beta-Cu3Ti). The hardness, yield strength, elongation of the CuTiCrMg alloy after aging at 450 degrees C for 30 min are 394 HV, 1057 MPa, and 1.6%, respectively. While, those of the CuTiCrMg-Fe alloy are 370 HV, 1160 MPa, and 10%, respectively. The precipitation strengthening is the primary strengthening mechanism. These findings are of great significance for developing Cu-Ti alloys with high strength and high plasticity.
10.1016-j.msea.2021.141639	-1		The high performance of copper alloys is widely welcomed due to their high electrical conductivity and excellent mechanical properties. These alloys are mainly used in electrical, electronic and aerospace fields. In the present work, we proposed a new class of Cu-Co-Si-Ti alloys by incorporating the multiple alloying elements, resulting in the multiple strengthening during heat treatment. It can be observed that Ti addition can significantly improve the micro-hardness of the Cu-Co-Si-alloy. Solution strengthening, deformation strengthening and dual-nanoprecipitation strengthening led to the Cu-Co-Si-Ti alloy with excellent tensile strength (617.9 MPa) and high electrical conductivity (41.7% IACS) using the optimal process of cold rolling by 50% and aging at 500 degrees C for 30 min. Electron backscatter diffraction technology was used to analyze the microstructure and texture evolution during the copper alloys aging process. It was found that the volume fraction of Goss, Brass, copper and S texture had close connections with the mechanical properties. From multiple strengthening mechanisms, the dual nanoprecipitation strengthening contributed the most due to the nanoprecipitation of Co2Si and Cu4Ti.
10.1016-j.msea.2021.141676	-1		The article describes a method for producing semi-finished products from a copper alloy of the Cu-Ni-Cr-Si system for electrical purposes through the radial-shear rolling (RSR). From the Cu-Ni-Cr-Si alloy by hot deformation, rods with a diameter of 20 mm were obtained, which were then heat treated with quenching and aging. A detailed analysis of the microstructure and properties (mechanical and electrical) of the obtained samples was carried out after RSR and after heat treatment (HT). After RSR, material hardening occurs due to shear deformations forming a gradient structure with grain sizes varying from 8.22 mu m to 15.95 mu m between the surface and the center of the rod. The microstructure and mechanical property analysis showed that after heat treatment, the alloy is thermally hardened due to the precipitation of Ni2Si and Cr3Si particles uniformly distributed in the sample volume in the form of fine inclusions with an average size of 0.56-0.65 mu m. After heat treatment, the alloy enhanced its mechanical properties (ultimate tensile strength (UTS)-700-750 MPa, yield strength (YS)-557-606 MPa, and elongation between 17 and 22%) and its electrical conductivity of 45.17% IACS from the 30.52% IACS of the RSR material. The improved mechanical properties of the heat-treated material are due to the different strength contributions mainly coming from dislocations and precipitates. The electrical conductivity improvement after the heat treatment is related to the dislocation density reduction and the increase in grain boundary misorientation due to the recrystallization phenomenon giving rise to a lower number of boundaries but with a twinning character. Thus, the RSR method offers a new industrial alternative for the production of semi-finished products from a Cu-Ni-Cr-Si alloy in the form of rods with diameters ranging from 10 to 55 mm.
10.1016-j.msea.2021.141760	6	grain; deformation; strain; strength; dislocation; cu-; tensile; size; ecap; grain size; sfe; ductility; hardening; high; stress	The influence of the structural state on deformation mechanisms under large strains was investigated in a Cu-2 wt% Be alloy. Torque evolutions during straining exhibit serrations typical of structural relaxations in the precipitation-hardened alloy, but not in the solid solution state. Microstructure characterization revealed that homogeneous deformation of the solid solution led to strong grain size reduction (20 nm), while localization occurred in the precipitated state with numerous shear bands. The role of CuBe precipitates on hindering dislocation glide and the resulting shear localization under large strain is discussed.
10.1016-j.msea.2021.141818	7	irradiation; shear; grain; ta; deformation; size; radiation; voids; nanocrystalline; simulations; similar; void; temperature; irradiated; boundaries	In this work, various alloy compositions of immiscible copper-tantalum (Cu-Ta) are systematically studied to understand the interplay between cluster stability, precipitation hardening, and the overall stability of the matrix's average grain size. An alloy composition of Cu-3at%Ta is found to exhibit dramatic improvements relative to other neighboring Ta contents (both higher and lower) only after exposures of more than 300 h at 800 degrees C. An extremely low steady-state growth rate, i.e., 3.1 nm per 100 h exposure, speaks to the extreme kinetics which allow this composition to retain its high mechanical strength . The key attribute responsible for the NC Cu-3at%Ta alloy exhibiting such behavior is a high cluster density tailored through the Ta solute content to achieve the best combination of stability without sacrificing strength by limiting Orowan coarsening of the clusters compared to other Ta concentrations. In general, the growth kinetics of this Cu-3at%Ta alloy are so sluggish that it places it among the most thermally resistant alloys ever produced. The work demonstrates that, if designed properly, bulk nanocrystalline alloys can withstand the prolonged high-temperature exposure required for high-temperature applications, while grain growth is stagnated or halted.
10.1016-j.msea.2021.141862	6	grain; deformation; strain; strength; dislocation; cu-; tensile; size; ecap; grain size; sfe; ductility; hardening; high; stress	Hot deformation behavior of an as-cast Cu-Ni-Si alloy with columnar grains in terms of flow stress, constitutive equation, processing map, microstructure evolution, and dynamic precipitation was investigated at deformation temperatures of 500 degrees C-800 degrees C and strain rates of 0.01 s(-1)similar to 1 s(-1). The results revealed that the true stress-strain curves of the as-cast Cu-Ni-Si rods exhibit continuously increased flow stresses. The relationships between the material parameters and strains were then modified by fourth power polynomial functions. Good fitness between the material parameters and strains was obtained. The constitutive equation derived using these relations predicts quite accurate values. Microstructure observed by confocal laser scanning microscopy, electron backscattered diffraction, and transmission electron microscopy indicated that the main hardening mechanisms of the continuously increased flow stress are attributed to the progressively occurred dynamic recrystallization and dynamic precipitation. The dynamic precipitates, unlike in the aged alloys, are very fine and have multiple orientation relationships with the Cu matrix, which is likely linked with the change of edge-on habit planes due to the plastic deformation and temperature imposed. It has also been found that the processing map developed is also dependent on the strain selected. The processing maps developed at low strains contain larger instability regions than those developed at high strains, which agree with the results of microstructure observations.
10.1016-j.msea.2021.141919	10	composites; nanoparticles; strength; matrix; high; strengthening; particles; conductivity; composite; electrical; mpa; sintering; ods; grains; mechanical	High strength conductive materials are the basic materials in the fields of electronic communication and mechanical manufacturing. In this study, we synthesize high-strength and high-conductivity bulk CuCrZr alloy/ CuZrAl metallic glass composites (CA/CMGCs) via spark plasma sintering (SPS) process. The effect of CuZrAl metallic glass (MG) content on the mechanical and electrical properties of the composites is investigated. The CuZrAl MG provides high strength and the CuCrZr alloy contributes significantly to the plasticity and conductivity of the composites. In addition, it is demonstrated that a good bonding state between metallic glass and crystalline alloy contributes primarily to the high strength and high conductivity of the bulk CA/CMGCs. This study provides insights into the untapped potential of high-strength and high-conductivity Cu matrix crystal/ amorphous composites.
10.1016-j.msea.2021.141952	-1		It is of significant interests to enhance the strength of Cu alloys while retaining their good electrical conductivity for broad applications. In situ incorporation of nano-phase into Cu alloys is a promising method for this objective. However, little success has been reported. In this study, we successfully fabricated in situ Cu-TiB2 nanocomposites by a molten salt processing and systematically studied their mechanical and electrical properties. During the processing, Al was used to react and introduce nano- and submicron-size TiB2 efficiently into the copper melt. Immiscible Fe was later added to recover the electrical conductivity through sequential solutionizing, hot rolling, and electrical conductivity-recovering. Detailed microstructure, phase, and electrical studies validate the feasibility of the proposed procedures to achieve high-strength and high-conductivity Cu(-Fe)-TiB2 nanocomposites. Cu-1 wt% Fe-5 vol% TiB2 offers 554.3 MPa in ultimate tensile strength, 4.4% in ductility, and 62.4% IACS in electrical conductivity. The new method paves an effective way to synthesize and incorporate nano-phase into copper melt for high-performance Cu nanocomposites.
10.1016-j.msea.2021.141955	-1		Coherent cuboidal precipitation of gamma' (Ni3Al) phases can significantly improve the high temperature properties of Cu-Ni-Al alloys, in which, substantial gamma' phases and a suitable lattice misfit degree between gamma (Cu matrix) and gamma' phase (delta gamma-gamma') is necessary. However, the re-dissolution and grain boundary discontinuous precipitation would induce the degradation of heating resistance in the alloys with higher Cu content. Herein introducing Si with strong elemental interaction to resolve this issue. In this research, series of Cu85.71Ni10.72-x Al3.57Six (x = 0, 0.45, 0.89, 1.34 and 1.79) alloys are designed and prepared, and the effect of Si addition on microstructure, properties at room or high temperature are investigated. The results demonstrate that Si with completely solution state has an effect on the promoting of gamma' precipitation and suppression of the discontinuous precipitation. Meanwhile, Si addition regulates the delta(gamma-gamma'), transforming the shape of gamma' phases from spherical to cuboidal and delaying the re dissolution of gamma' phase and improving the stability of matrix. First-principles calculations and work function results indicate that Gibbs free energy Delta G of gamma' phase decreases as well as exhibiting a more negative cohesive energy E-b for a suitable Si addition, which enables the alloys to be more stable and homogeneous. Si exhibits a good optimization effect for Cu-Ni-Al-Si alloy, which leads to excellent high temperature properties that can be extended to alloys with higher Cu content by Si addition. Therefore, multi-componentization is an efficient way to improve the properties of Cu-Ni-Al alloys, and an appropriate match in elemental interaction is crucial. The research provides theoretical and experimental basis for the development of heat-resistant Cu alloy with good comprehensive properties.
10.1016-j.msea.2021.141958	-1		In this study, the effects of pre-rolling and friction stir processing (FSP) on the microstructure and mechanical behavior of pure copper were investigated. With increasing the tool rotational speed from 400 to 800 rpm, the average grain size increased for both 0% (annealed) and 60% (pre-rolled) samples. Also, pre-rolling of copper led to a reduction in the average grain size of the FSPed samples. It was found that homogeneously distributed fine grains structure in the 400-100 (0%) (400 rpm-100 mm/min-with 0% pre-rolling), 400-100 (60%), and 800-100 (60%) samples were observed due to the large heat transfer caused by the copper backing plate. The application of rolling and FSP caused an improvement in hardness, yield strength, and ultimate tensile strength values due to the grain refinement mechanism. Among the FSPed samples, the 600-100 (60%) sample showed a better strength-ductility balance than the other samples. In the initial and FSPed samples, many dimples were observed, revealing the ductile fracture. With increasing the rotational speed, the dimples morphology became more homogeneous. Also, the pre-rolled samples had dimples smaller than the annealed samples.
10.1016-j.msea.2021.142006	-1		The Cu-9Al-4Ni-3.5Fe-0.5Mn Nickel-aluminum bronze (NAB) thin wall sample was prepared by laser melting deposition (LMD). The solidification characteristics, microstructure and mechanical properties were investigated. The LMD-NAB alloy consists of alpha, beta' and kappa(kappa(II), kappa(III), kappa(IV)) phase. The alpha phase shows directional growth trend along the deposition direction. Lamellar kappa(III) phase distributed in alpha, and spherical shell kappa(III) phase distributed on the surface of kappa(IV) phase were found. Spherical and parallelogram kappa(IV) phase was distributed in alpha phase. A core structure based on FeAl3 phase was located in the spherical and parallelogram kappa(IV) phase. The LMD-NAB alloy presents tensile properties with average ultimate tensile strength (UTS) of 645 +/- 5.7 MPa and elongation of 21.2 +/- 1.5% along the scanning direction, and tensile properties with average UTS of 637 +/- 9.9 MPa and elongation of 26.0 +/- 0% along the deposition direction. The fracture surfaces exhibit a mixture of brittle cleavage model and microvoid coalescence. This work shows great potential for fabricating NBA alloy by LMD technology.
10.1016-j.msea.2021.142012	15	aging; strength; conductivity; electrical conductivity; electrical; mpa; treatment; strengthening; degrees; cu-; cold; precipitation; tensile strength; tensile; iacs	The effect of Si on the microstructure and properties of Cu-10Fe alloy was systematically studied in this paper. By adding 0.4 wt% Si to Cu-10Fe alloy, the mechanical properties, electric conductivity, thermal conductivity, saturation magnetization and electromagnetic interference shielding effectiveness are significantly improved. After 90% cold rolling and 450 degrees C/32 h heat treatment, the electrical conductivity, thermal conductivity, tensile strength, elongation and electromagnetic interference shielding effectiveness of Cu-10Fe-0.4Si alloy are 68.02 % IACS, 304 W/(m.K), 521 MPa, 29.6% and 107.4 dB, respectively. Microstructure observation shown that FCC FeSi phases formed in two different sizes and the precipitation of the Fe atoms was promoted in Cu-10Fe-0.4Si alloy, which lead to the simultaneously improvement of conductivity, strength and magnetic properties. This high-strength, high-conductivity and magnetic Cu-Fe alloy has great application potential in electromagnetic shielding and other fields.
10.1016-j.msea.2021.142023	15	aging; strength; conductivity; electrical conductivity; electrical; mpa; treatment; strengthening; degrees; cu-; cold; precipitation; tensile strength; tensile; iacs	An in-depth exploration of the microstructure evolution and characterization of the dislocation density in Cu-Ni-Si-Co alloy was performed using X-ray diffraction electron backscattering diffraction, transmission electron microscopy, three-dimensional atom probe technique, and high-energy X-ray diffraction (HEXRD). The results reveal that the tensile strength and electrical conductivity of the alloy are 937.27 MPa and 45.57% IACS, respectively, and that it has good stress relaxation resistance. There are many dislocation tangles, dislocation lines, dislocation cells, and deformation twins in alloys processed by cyclic cryogenic rolling and lowtemperature aging. The alloy contains both 300-600 nm coarse particle precipitates and 5-10 nm rod-like nano-precipitated phases composed of (Ni, Co)2Si. The average dislocation density is (35.967 +/- 1.513) x 1014 m- 2, and the twin stacking-fault probability is 14.414 +/- 0.333 x 10-3 in the alloy aged at 350 degrees C for 2 h .
10.1016-j.msea.2021.142025	15	aging; strength; conductivity; electrical conductivity; electrical; mpa; treatment; strengthening; degrees; cu-; cold; precipitation; tensile strength; tensile; iacs	The effects of deformation on the aging precipitation behavior, recrystallization behavior and mechanical properties of Cu-15Ni-8Sn and Cu-15Ni-8Sn-0.2P alloys were investigated using scanning electron microscopy, high-resolution transmission spectroscopy, and electron backscatter diffraction. The results showed that during the aging process, the transformation from DO22 to the L1(2) ordered phase was restrained after cold deformation. However, the coarsening of the modulated structure was promoted. Moreover, the joint effect of discontinuous precipitation (DP) and recrystallization led to the deterioration of the mechanical properties in the late aging stage. The deterioration of the properties caused by DP was much more significant than that caused by recrystallization. Compared to the deformed Cu-15Ni-8Sn alloy, the deformed Cu-15Ni-8Sn-0.2P alloy was more prone to recrystallization reactions. This ultimately inhibited the DP during the aging process. Furthermore, the addition of P in the Cu-15Ni-8Sn alloy improved the peak values of the hardness and ultimate tensile strength, and had a negligible effect on the elastic modulus. The peak-age values of the ultimate tensile strength (yield strength) and elastic modulus of the 70%-cold-deformed Cu-15Ni-8Sn-0.2P aged at 400 degrees C were 1303 MPa (1280 MPa) and 145.0 GPa, respectively. Nevertheless, our results suggested that the precipitation strengthening, dislocation strengthening, and solution strengthening were the major strengthening mechanisms that improved the yield strength of the Cu-15Ni-8Sn-(P) alloy. The grain boundary strengthening had a negligible effect on the properties of the alloy. Compared to the Cu-15Ni-8Sn alloy, the increase in the yield strength of the Cu-15Ni-8Sn-0.2P alloy was mainly affected by precipitation strengthening.
10.1016-j.msea.2021.142123	-1		Cu-based amorphous alloy plates with good mechanical properties have tremendous potential applications as structural materials. However, there is a lack of effective methods for preparing such plates. In this work, 0.53mm-thick Cu47Zr45Al8 (at%) and 0.25-mm-thick Cu64Zr36 (at%) amorphous-alloy plates were prepared continuously by twin-roll strip casting, and their mechanical properties were investigated through both experiments and in-situ observations. The Cu-based amorphous-alloy plates prepared by strip casting were found to have good surface quality and shape; these plates did not exhibit tensile plasticity, but showed excellent bending and compression plasticity at room temperature. Such plasticity is achieved through the formation and evolution of multiple shear bands. Overall, the present study proves the feasibility of continuous preparation of amorphous Cu-based alloy plates with good plasticity by twin-roll strip casting and serves as a guide for this process in the future.
10.1016-j.msea.2021.142149	-1		This study investigated mechanical properties and texture evolution of Cu-xZn alloys (x = 5, 15, 20, 30) processed by multi-directional forging (MDF) up to 6 passes at ambient temperature. Mechanical properties were examined via shear punch and hardness tests. Optical microscopy and high-resolution scanning electron microscopy (HR-SEM), equipped with electron backscattered diffraction (EBSD) detector were also utilized to characterize the detailed microstructures and texture evolutions. The MDFed Cu-xZn alloys after 6 passes showed superior mechanical properties without the reduction of electrical conductivity. Hardness, ultimate shear strength and shear yield strength of Cu-30Zn alloy improved by 213%, 83% and 85%, respectively after 6 passes of MDF. Enhancement of mechanical properties can be attributed to grain refinement. The MDFed Cu-5Zn alloy presented a predominantly Copper-type texture due to the higher activity of shear bands. By increasing Zn to Cu15Zn and Cu-20Zn, Brass and Goss texture components were observed. Finally, Cu-30Zn alloy possessed a Brass texture which could be attributed to a higher amount of twinings.
10.1016-j.msea.2021.142220	-1		The age-hardening structure and mechanism of a Cu-3at%Ni-1.5 at%Si Corson alloy were elucidated using high-resolution scanning transmission electron microscopy. The alloy samples were solution-treated at 850 degrees C and reached peak strength after 6 h of aging at 450 degrees C. The hardening structure is composed of delta '-Ni2Si precipitates, which are slightly distorted from delta-Ni2Si (oP12, Pnma, C23, Prototype: Co2Si) by the Cu matrix to increase coherence. After identifying the structure using atomic-resolution energy dispersive X-ray spectroscopy, the electron diffraction pattern could be completely indexed. The delta '-Ni2Si precipitates have stacking faults on the (004)(delta-Ni2Si) planes, which result in dark bands in the transmission electron microscopy image of the precipitates and streaks in the electron diffraction pattern. No interface-like crystal habit plane or rigid boundary was observed between the delta '-Ni2Si precipitates and the Cu matrix, indicating a diffuse boundary. The delta '-Ni2Si lattice had corresponding planes that were almost parallel and approximately equal to all the planes in a particular slip system: {111}(Cu) < 110 >(Cu). From their orientation relationships, the precipitates were to be coherent with the matrix. Under the conditions of this study, the precipitates grew via Ostwald ripening and supported the peak strength via precipitation hardening with the cutting mechanism.
10.1016-j.msea.2021.142287	-1		The Cu-15Ni-8Sn-XZr (wt%, X=0-0.7) alloys were prepared by vacuum melting, and their microstructural evolutions during the solidification and heat-treatment processes were systematically investigated as well as the corresponding mechanical properties. Zr addition could offer a significant effect on the dendritic morphology by controlling the constitutional supercooling in solidification front, and it also made the gamma-phase more likely to form in the needlelike-shape rather than the lamellar-like shape in subsequent cooling process. After solution treatment, the Zr atoms with a low content of 0.1 wt% were completely solidly dissolved in the alpha-matrix. With its content increasing to 0.3 and 0.5 wt%, the existence form was changed into the nano-scale precipitation phase (Ni5Zr) and then to micron-scale segregation phase (Ni4SnZr). The presence of Zr could significantly extend the aging window of alloy and improve its mechanical properties by inhibiting the nucleation and growth of discontinuous precipitation (DP), and there was few DP even after 16 h aging. The optimal combination of properties was obtained for Cu-15Ni-8Sn-0.5Zr alloy aged at 673 K for 4-16 h, including a hardness of 330HB, ultimate tensile strength (UTS) of 980 MPa and electrical conductivity of 9%IACS.
10.1016-j.msea.2021.142326	-1		In this article, in order to study the hot deformation behavior of Cu-20 wt%W composite and reveal the strengthening mechanism of W particles, Cu-20 wt%W composite with a high relative density of 94.87% was prepared via spray drying technology and spark plasma sintering method. The tungsten particles have a good bond with the copper matrix because of the diffusion layer. Thus the Vickers hardness of Cu-20 wt%W composite is 120 HV, which is 110.52% higher than that of pure Cu, and the compression yield strength of Cu-20 wt%W composite at room temperature is 338 MPa, 338.96% higher than that of pure Cu. Meanwhile, the hot deformation behaviors of Cu-20 wt%W and Cu samples at 300-600 degrees C with a strain rate of 0.01 s-1 were studied in detail, and the critical strains of dynamic recrystallization were calculated. The tungsten particles can pin and accumulate the dislocations to result in high dislocation density and high recrystallization force, thus the critical strain values of Cu-20 wt%W composite under different temperatures are lower in comparison with the corresponding values of Cu. Furthermore, the Cu-20 wt%W composite is not as sensitive as Cu samples to elevated temperatures, and the tungsten particles can improve the high-temperature stability of Cu-W composites. When the deformation temperature is 300 degrees C, the peak stresses of Cu and Cu-20 wt%W composite are 198.44 MPa and 223.46 MPa respectively, and the peak stress value of Cu-20 wt%W composite is only 12.61% higher than that of Cu. However, when the deformation temperature rises to 600 degrees C, the peak stress percentage increment in Cu-20 wt%W composite compared with pure Cu increases to 128.37%.
10.1016-j.msea.2021.142353	-1		The CuCr0.8Zr0.12Six (wt%, x = 0, 0.02, 0.05 and 0.2) alloys were designed and prepared by casting method. The function mechanism of Si content on as-cast microstructure evolution and properties was revealed with the guidance of thermodynamic analysis and first-principles calculation. Cr3Si tends to form during solidification at higher Si content due to its relatively low excess Gibbs free energy, which was proven to significantly affect the mechanical properties of alloys. The relationship between microstructure and mechanical properties of as-cast CuCr0.8Zr0.12Six alloy was also experimentally investigated. With Si content increasing from 0 to 0.2 wt%, the tensile strength and elongation of the CuCr0.8Zr0.12Six alloys simultaneously increase from 251 MPa to 29.0% in CuCr0.8Zr0.12Si0 to 268 MPa and 33.0% in CuCr0.8Zr0.12Si0.05, and then decrease to 229 MPa and 23.7% in CuCr0.8Zr0.12Si0.2. Simultaneously, the electrical conductivity and hardness of CuCr0.8Zr0.12Si0.05 respectively reach 57.2 %IACS and 85.1 HV, CuCr0.8Zr0.12Si0.05 was thus identified to be the best composition with relatively high comprehensive properties in this case.
10.1016-j.msea.2021.142511	15	aging; strength; conductivity; electrical conductivity; electrical; mpa; treatment; strengthening; degrees; cu-; cold; precipitation; tensile strength; tensile; iacs	In this study, Cu-0.26Cr-0.14Mg and Cu-0.26Cr-0.14Mg-0.02Si (wt%, nominal composition) alloys were used to study the effect of adding a small amount of Si on the comprehensive properties, microstructure by thermomechanical treatment. The properties results showed that the Cu-0.26Cr-0.14Mg-0.02Si alloy had a higher strength and electrical conductivity than Cu-0.26Cr-0.14Mg alloy. After 80% cold rolling and aging at 500 degrees C for 20 min, the hardness, tensile strength, and electrical conductivity of Cu-0.26Cr-0.14Mg-0.02Si alloy reached 162.8 HV, 523 MPa, and 82.0 %IACS, respectively. The microstructure results showed that Cr particles existed in the form of G.P zones in the early stage of aging, and there were three forms of existence in the later stage of aging: coffee-beans, Moire fringes, and rod-like precipitates. The addition of Si greatly promoted the precipitation of the alloying elements, increased the fraction of the precipitates, refined the size of the precipitates, and thus improved the Orowan-Ashby strengthening and dislocation strengthening effects.
10.1016-j.msea.2021.142577	15	aging; strength; conductivity; electrical conductivity; electrical; mpa; treatment; strengthening; degrees; cu-; cold; precipitation; tensile strength; tensile; iacs	The C70250 copper alloy billet produced by continuous directional solidification technology was cold rolled and aged. The influences of cold rolling deformation and aging process on the microstructure, mechanical and electrical properties of the alloy were investigated, and the mechanism was also revealed. Our results indicate that the peak aging tensile strength and electrical conductivity of the C70250 copper alloy gradually increase with the increase of cold rolling deformation amounts. When cumulative cold deformation amount reaches 95%, the aging treatment of 450 degrees C and 1 h was the optimal heat treatment process, the yield strength of the alloy is 720 MPa, the tensile strength is 758 MPa and the conductivity is 52.5% IACS under this condition. Compared with the traditional preparation process, the comprehensive properties are significantly improved. Large cold rolling reduction makes the columnar grain structure of C70250 copper alloy produce uniform shear deforma-tion, promotes the uniform precipitation of Ni2Si phase in the aging process, leading to finer precipitates and more uniform distribution in the peak aging alloy. Dislocation slip is hindered, grain boundary migration capacity is reduced and the strength of the alloy is improved. The parallel shear band produced by large defor-mation cold rolling cuts the matrix evenly, which not only leads to the transformation of columnar grain structure into fiber strip structure, reduces the transverse grain boundary density, but also accelerates the pre-cipitation of solute atoms, reduces the influence of solute atoms on electron scattering. Besides, the long fiber structure provides a channel for free electron transport, greatly reduces the barrier of electron transmission and improves the conductivity of the alloy.
10.1016-j.msea.2022.142615	-1		Ti3AlC2 is a promising reinforcement for Cu matrix composites. In this paper, the Cu/20 wt%Ti3AlC2 composites were fabricated using a spark plasma sintering process at various sintering temperatures. The thermodynamic calculation and high-temperature X-ray diffraction results showed that Al element preferred to dissolve from the metastable Ti3AlC2 and diffused into Cu matrix to form Cu(Al) solid solution at temperatures ranging from 600 to 1000 degrees C. The TiCx -> Ti3AlC2 -> Cu(Al) gradient interface features were in-situ produced in the sintered composites and thus contributed to the improvement of the microhardness and the compressive yield strength . The composite sintered at 1000 degrees C demonstrated the maximum microhardness of 161.6 HV0.2 and the maximum compressive yield strength of 348 MPa. In-situ tensile test inside SEM revealed that cracks generated from the edge of the specimen and extended along the interface between the Ti3AlC2 reinforcement and the Cu matrix. The present composite interface strategy will provide flexibility to optimize the interface microstructure and the overall properties of the metal matrix composites.
10.1016-j.msea.2022.142654	-1		Distribution of electrical energy through subsea power cables has an increasingly important role in the renewable power generation. The majority of the subsea cables uses copper (Cu) as a conductor material. Cables suspended from sea level to sea floor are subjected to both static and cyclic loads that can introduce microstructural damage due to fatigue, creep and their interaction. In addition, since the manufacturing process of the stranded conductor results in Cu-materials with superficial irregularities and metallurgical anisotropy, the material performances need to be carefully addressed in order to reliably assess the wires life. In order to provide a deeper insight into the occurring damage mechanisms, monotonic and cyclic tests of micro-sized Cu tensile specimens were carried out using in-situ micromechanical testing, inside a scanning electron microscopy (SEM) equipped with an electron backscatter diffraction. Tensile and cyclic loading behavior are discussed in correlation with the damage mechanisms observed directly and post-mortem. The twin boundary fraction in the microstructure is found to be linked to the deformation status, and thus can potentially be used as an indicator for predicting the remaining life of the material under service conditions.
10.1016-j.msea.2022.142672	-1		To synergistically improve the strength-ductility of copper alloys used in the miniaturized component, Cu-3.2Ti0.2Fe-0.2V alloy with heterogeneous structure was obtained by thermo-mechanical treatment (namely, short time annealing). The heterogeneous structure was composed of the non-uniform grains formed due to Laves phase inhibiting grain growth and FCC structured Cu4Ti phase with good coherent interface precipitated on the grain boundaries in sub-micro size. After aging at 400 degrees C for 2 h and then 450 degrees C for 4 h, the ultimate tensile strength and elongation of the heterogeneous-structured alloy were 976.8 MPa and 18.8% respectively, which was approximately 120 MPa more than that of the coarse-grained alloy after complete annealing, but both alloys had comparable ductility. When cold-rolling with 5% reduction was carried out before the aging of 450 degrees C, the strength increased to 1057 MPa and corresponding elongation was still over 10%. The strengthening mechanism of alloy with heterogeneous structure was analyzed and the hetero-deformation induced hardening of 284.5 MPa was the other significant reinforcement. The semi in-situ observation of tensile deformation behavior shown that the superior ductility in coarse-grained alloy was mainly attributed to the slipping and twinning. While grain rotation and grain boundary sliding were additional deformation mechanism in heterogeneous-structured alloy during tensile deformation, meanwhile, the texture of S, {110}<1 <(1)over bar> 1> and {331}<1<(2)over bar> 3> components converted to the texture of {441}<<(11)over bar> 8>, Goss, Copper and {012}<8<(2)over bar>1> components. The deteriorative ductility after rolling with the reduction of 5% was owing to the S and Cube components converted to the strong texture of {032}<22<(3)over bar>> components.
10.1016-j.msea.2022.142740	-1		The evolution of the microstructure and mechanical properties of Cu-Cr-Zr manufactured by selective laser melting (SLM) with different scanning parameters was studied. Accordingly, the Cu-Cr-Zr specimens with high relative density (99.5 +/- 0.3%) were obtained by optimizing the scanning parameters and they also possessed the highest strength (280 +/- 6 MPa) and ductility (23.4 +/- 0.4%) compared to other SLM manufactured specimens. The crystallographic texture and the grain microstructure of the specimens for the horizontal and vertical planes all exhibit the same anisotropic trend, which is independent of the volumetric laser energy density and the defects in the specimen. The formation of twins in the specimen is mainly due to the combined effects of large residual stress, low stacking fault energy and intrinsic heat treatment. The Cr-Zr-Cu nano precipitates formed in the specimen can be attributed to the effect of intrinsic heat treatment during the SLM process. These twins and nano precipitates in the microstructure both contribute to the abovementioned excellent mechanical properties of SLM manufactured specimens.
10.1016-j.msea.2022.142775	-1		Cu-10 wt% Sn (Cu-10Sn) alloy specimens were additively manufactured by varying the laser powder bed fusion (LBPF) processing parameters, e.g., laser power (200-350 W) and laser scan speed (100-1400 mm/s) at a fixed hatch spacing (0.12 mm) and slice thickness (0.03 mm), to examine their effects on the density, melt pool structure, and microstructure. Microstructural characteristics of the most dense sample were examined using electron microscopy (SEM, TEM) and X-ray Diffraction. The grains in the top-most melt pool layer showed a fanlike structure, whereas all other areas showed small columnar structure aligned nearly parallel to the build direction due to multiple melt-solidification cycles. The high cooling rates associated with LPBF yielded a fine dendritic microstructure, which consisted of primary alpha(1)(Cu) dendrites and a mixture of alpha(2)(Cu) and delta (Cu41Sn11) phases in the interdendritic region. In addition, formation of thin laths (similar to 120 nm) was observed by TEM presumably due to diffusionless martensitic transformation from the high temperature beta phase associated with fast cooling rates. The primary alpha(1)(Cu) dendrite and alpha(2)(Cu) within the interdendritic region contained low (similar to 6.6 wt%) and high (similar to 11.9 wt%) Sn concentration, respectively. Mechanical properties in tension of the dense Cu-10Sn alloy was measured in as-built condition, i.e., sigma(UTS) = 564 MPa, sigma(Y) = 387 MPa, El = 26%; these are significantly superior to the properties determined in previous LPBF investigations and as-cast Cu-10Sn alloy, most likely due to contributions from Hall-Petch and dislocation strengthening mechanisms. Solidification path in LPBF fabricated Cu-10Sn alloy was also revealed from an extensive TEM investigation.
10.1016-j.msea.2022.142815	15	aging; strength; conductivity; electrical conductivity; electrical; mpa; treatment; strengthening; degrees; cu-; cold; precipitation; tensile strength; tensile; iacs	Developing high-performance copper alloys while simultaneously improving ultimate tensile strength (UTS) and electrical conductivity (EC) has been a key challenge and direction. Two thermo-mechanical processes were employed in this study to achieve simultaneous enhancement of UTS and EC of the Cu-3.08Ni-0.61Si-0.17Zn0.17Cr-0.04P alloy. After the two-stage cold-rolling and aging process (85% cold-rolling + 450 degrees C@60 min aging + 95% cold-rolling + 450 degrees C@30 min aging, referred to as Process A), the alloy's UTS and EC of the alloy are 856 +/- 26 MPa and 52.4 +/- 0.8% international annealed copper standard (IACS). The mechanical and electrical properties of the alloy with process A are much better than those of the alloy with single stage cold-rolling and aging treatment process (85% cold-rolling + 450@60 min aging, 786 +/- 12 MPa, 47.5 +/- 0.9% IACS). The UTS of the alloy reaches 905 +/- 11 MPa with pre-aging + two-stage cold-rolling-aging (450 degrees C@90 min pre-aging + process A, referred to as process B), and the EC reaches 52.5 +/- 0.2% IACS, indicating that process B enhanced the strength over process A. A large number of nano-scale delta-Ni2Si precipitates are observed in the samples after primary aging of process A and pre-aging of process B, leading to a more diffuse dislocation distribution during subsequent cold-rolling and then promoting further precipitation of the solute atoms during subsequent aging processes. In the samples treated by both process A and B, there are two sizes of delta-Ni2Si phase precipitates, simultaneously enhancing UTS and EC of the Cu-Ni-Si alloy.
10.1016-j.msea.2022.142927	15	aging; strength; conductivity; electrical conductivity; electrical; mpa; treatment; strengthening; degrees; cu-; cold; precipitation; tensile strength; tensile; iacs	Addition of a small amount of Ti can significantly improve strength of Cu-Cr alloys. Previous work found that addition of Ti produced both spherical and cubic-shaped Cr particles. In this work, the hindering effect of Cr particles with different morphologies on dislocation was further studied. Transmission electron microscopy and high-resolution transmission electron microscopy were used to observe the bending angle of dislocations cutting through precipitated phase particles at about 108 degrees or 54 degrees. The angle of dislocations cutting through the spherical particles was 108 degrees and that of the cubic particles was 54 degrees. Theoretical calculations of dislocation bending angle to enhance strength determined that the bending angle of dislocations cutting cubic particles is about 54 degrees. This study provides new insights for the design and preparation of high-strength and high-conductivity copper alloys.
10.1016-j.msea.2022.142934	-1		In this paper, dense Cu-15Ni-8Sn alloy blanks were fabricated by laser-directed energy deposition (L-DED). Then, we systematically compared the L-DED sample with the laser-powder bed fusion (L-PBF) Cu-15Ni-8Sn alloy sample prepared in our previous work in terms of their building rate, microstructure, and performance. The average grain size of the L-DED sample was about 23.3 +/- 16.7 mu m, and its microstructure mainly included fine dendrites with a width of 5.6 +/- 1.2 mu m. The Vickers hardness, yield strength, and elongation at break of the L-DED sample were 166 +/- 5HV1, 327 +/- 9 MPa and 23.9 +/- 3.2%, respectively. The building rate of L-DED was about 16 times that of L-PBF. Due to the different laser power densities and different melting modes of L-DED and L-PBF, there were various preferred orientations along the laser scanning direction. Compared with the L-PBF sample, the sizes of grains, dendrites, and segregated phases of the L-DED sample coarsened, and its dislocation density decreased. Combined, these factors decreased its yield strength and were primarily responsible for the lower cooling rate of L-DED. The slow cooling rate alleviated the local thermal deformation in the L-DED sample, which reduced the possibility of stress concentration and increased its plasticity and work hardening rate.
10.1016-j.msea.2022.142945	1	shape; memory; shape memory; damping; martensite; martensitic; damping capacity; transformation; capacity; strain; superelasticity; temperature; cu-al-mn; shape memory effect; effect	In this study, the strain distribution and elastocaloric effect during compression of a superelastic [116]-oriented single-crystal Cu-Al-Mn shape memory alloy were investigated. Its superelastic behavior exhibited low critical stress (213 MPa), narrow stress hysteresis (111 MPa), and excellent superelasticity (near 9%). The detailed evolution of strain field during the superelastic cycle was analyzed by digital image correlation method. Multiple variants were triggered during its superelastic deformation, and uneven strain distribution was observed in the strain field. The temperature and strain fields of the four side surfaces showed inhomogeneous transformation in the single-crystal alloy. The elastocaloric temperature drops ranged from 3.1 K to 12.3 K when the sample was unloaded from prestrains of 2 %-9 %. The calculated theoretical elastocaloric effect was compared with the measured temperature drop, and the differences were confirmed to be related to non-uniform and incomplete martensitic transformation. This study presents a comprehensive analysis of the inhomogeneous transformation behavior and elastocaloric effect in [116]-oriented Cu-Al-Mn single-crystal alloy.
10.1016-j.msea.2022.143004	-1		The precipitation behavior and the microstructural evolution of a dual-phase Cu-15 wt%Ag alloy during annealing were investigated. We discussed the effects of dislocation density, grain size, solute atom concentration, and precipitation morphology on strength and electrical conductivity. The results showed that continuous precipitation and discontinuous precipitation simultaneously occurred during the annealing of the Cu-15 wt%Ag alloy. It was accompanied by pronounced recovery and recrystallization, significantly decreasing the strength and electrical resistivity of the cold-rolled Cu-15 wt%Ag alloy. After 48 h of annealing at 350 degrees C, the fully recrystallized Cu-15 wt%Ag alloy exhibited a higher strength (299 MPa) and a lower electrical resistivity (1.92 mu Omega cm) compared to the samples annealed at higher temperatures. The higher strength was attributed to smaller grain size and higher volume fraction of the continuous precipitation zone. Nanoscale Ag precipitates formed by continuous precipitation provided more extensive precipitation strengthening than sub-micrometer Ag precipitates formed by discontinuous precipitation. In addition, reducing the dislocation density and the concentration of solid atoms by controlling the annealing conditions was an effective strategy to weaken the dislocation scattering and impurity scattering effect in the Cu-15 wt%Ag alloy. The electrical resistivity of the fully crystallized Cu-15 wt%Ag alloy was linearly correlated to the concentration of Ag solute atoms. The electrical resistivity of the annealed Cu-15 wt%Ag alloy increased by 0.117 mu Omega cm when 1 at% Ag was dissolved in the Cu solid solution.
10.1016-j.msea.2022.143055	-1		Brass alloys containing low boiling-point element zinc are hard to be formed by selective laser melting (SLM). In this study, a Cu-12.9Zn-2.5Si silicon brass was produced successfully by SLM via optimizing process parameters, and then subjected to isothermal annealing at 873 K with different holding time. The evolutions of micro-structure, mechanical and corrosion properties were investigated systematically by X-ray diffraction, scanning electron microscopy, electron back-scattered diffraction and so on. Our results showed that nearly full-dense brass could be obtained with the laser scanning speed below 200 mm/s. The optimum specimens displayed high tensile and compressive yield strength, and {110}< 001 > Gaussian texture. After annealing, cellular structure in the SLM specimens changed into high-density annealing twins, accompanied with weakening of the texture. The decomposition of the cellular structure resulted in a significant improvement of corrosion resistance but a decrease in tensile and compressive yield strength . Strengthening mechanism analysis demonstrated that that strengthening contribution of cellular structure was more significant than that of annealing twins. The obtained results will provide some guidelines for the production of high-performance silicon brass alloys by SLM for structural applications.
10.1016-j.msea.2022.143250	-1		The mechanical performance of Cu-Cr alloy severely deteriorates at high temperatures due to the Cr precipitates coarsening rapidly or dissolving in Cu matrix again. This study achieved the supersaturated solid solution Cu-5wt%Cr alloy (S1) with Cr solubility of 0.94 wt% by combining mechanical alloying and spark plasma sintering. The effect of residual Cr precipitates on the high temperature hardness, softening resistance and microstructures were investigated. The results showed that S1 alloy exhibited an excellent hardness of 106.27 HV at 500 degrees C, 23.14% higher than the common sample. The softening temperature of S1 alloy is 800 degrees C (0.74Tm), and the average grain size of S1 alloy annealed at 800 degrees C is 0.69 mu m, which increased by only 0.11 mu m. The microstructural evolution showed that the high thermal stability is mainly attributed to two kinds of residual Cr precipitates in the matrix. The larger ones act as obstacles to inhibit the motion of Cu grain boundaries, and the fine precipitates disperse in Cu matrix to fix the dislocations. Combining these two types of residual Cr precipitates act as very powerful obstacles to inhibit the motion of dislocations and grain boundaries. Also, the increment in yield strength at elevated temperature (300-700 degrees C) deduced from the residual Cr precipitates strengthening ranges from 320 MPa to 337 MPa.
10.1016-j.msea.2022.143281	15	aging; strength; conductivity; electrical conductivity; electrical; mpa; treatment; strengthening; degrees; cu-; cold; precipitation; tensile strength; tensile; iacs	Modern electronic components put forward higher requirements for copper-based alloys, hoping to have high elastic properties and stress relaxation resistance. The addition of Fe increased the dislocation density, tensile strength, and the number of deformed bands after cold rolling. After cold rolled by 94% and aged at 450 C for 5 min, the hardness, tensile strength, and elongation of the CuTiCrMg-Fe alloy was 448 HV, 1610 MPa and 4.75%, respectively. Adding Fe can improve the stress relaxation resistance of samples, and the stress relaxation rate of the CuTiCrMg-Fe alloy was 14.7% after loading at 200 C for 100 h . The stress relaxation process of Cu-Ti alloys is mainly divided into the dislocation's reaction stage and dislocations and precipitates' interaction stage. These findings have important implications for the development of Cu-Ti alloys with high strength and high stress relaxation resistance.
10.1016-j.msea.2022.143283	15	aging; strength; conductivity; electrical conductivity; electrical; mpa; treatment; strengthening; degrees; cu-; cold; precipitation; tensile strength; tensile; iacs	Cu-Ni-Si alloy has a difficult combination of high strength and high electrical conductivity, which limits its further application in electronics industry. In this work, the effects of large deformation double cold rolling-aging processes on the microstructure, mechanical properties and electrical conductivity of the columnar grain alloy were studied, and its mechanism was revealed. The results show that the C70250 copper alloy strip prepared by hot mold continuous casting technology can be directly subjected to large deformation double cold rolling-aging treatments without solid solution process. The excellent balance of tensile strength and electrical conductivity, as high as 884 MPa and 45.7% IACS, respectively, can be obtained for the alloy after primary 95% cold rolling and aging at 450 degrees C for 45 min followed by secondary 60% cold rolling and aging at 400 degrees C for 10 min. The strength and electrical conductivity is better than the similar products reported. The realization of high strength and high electrical conductivity is attributed to the interaction between strain hardening and precipitation behavior of columnar alloy during double deformation and aging treatment. The repeated introduction of large deformation cold rolling provides a new short diffusion driving force for the precipitation of solute atoms by GPA and APT results, the precipitation rate is increased in the second stage of aging. At the same time, the nanometer-sized strengthening phase formed by primary aging can effectively nail the dislocations formed in the secondary cold rolling process, and finally form a fibrous structure with uniform mixing of multi-scale nano cluster and Ni2Si phase. The strength of the alloy is significantly improved by dislocation strengthening and multi-scale precipitation strengthening. C70250 copper alloy precipitate as many solute atoms as possible, and retains fibrous structure, the dispersing of electrons by solute particles and grain boundary limits is fundamentally diminished, and the electrical conductivity is improved.
10.1016-j.msea.2022.143309	-1		The effects of Zr addition on the solidification structure and mechanical properties of a Cu-10 wt%Fe alloy were investigated. Grain refinement results from the in-situ synthesis of the ZrFe2 nucleation substrate during solid-ification. The enhanced mechanical properties can be attributed to the additional precipitation of Cu4Zr and ZrFe2 during ageing.
10.1016-j.msea.2022.143395	15	aging; strength; conductivity; electrical conductivity; electrical; mpa; treatment; strengthening; degrees; cu-; cold; precipitation; tensile strength; tensile; iacs	To achieve high strength and good electrical conductivity, thermo-mechanical treatments are usually applied for precipitation strengthened Cu-Cr-Zr alloys. However, the dislocation-precipitate interaction is still unclear for these alloys during deformation and post-aging, which hinders a further improvement in their mechanical-electrical properties. In the present study, to investigate the effect of precipitates' size and their orientation relationship with the Cu matrix on the dislocation accumulation during rolling and post-aging, a thermo-mechanical treatment was fulfilled by adjusting the pre-aging state of the alloys. Samples with four precipitate states (solid solute, under-aged, peak-aged, and over-aged) were subjected to rolling and post-aging, respectively. The results showed that, the under-aged sample with less precipitates accumulated the similar deformed structure as the peak-aged one during rolling and relieved the negative effect caused by aging recovery during post-aging, retaining more deformed structure. Therefore, the ultimate tensile strength reached to 588 MPa, similar to 30 MPa higher than those with other pre-aging treatments. Additionally, the re-dissolution and refinement of precipitates caused the abnormal decrease of electrical conductivity during rolling, and the post-aging treatment restored the electrical conductivity to the normal level (81% IACS). The results indicate that a proper under-aging pre-treatment before rolling helps to obtain better mechanical properties, which is feasible for large-scale industrial production and can be extended to other thermo-mechanical treatment forms.
10.1016-j.msea.2022.143397	-1		Sulfur (S), as an impurity element in copper and copper-based alloys, usually leads to intergranular embrittlement even at ppm concentrations. However, the intrinsic mechanisms of the embrittlement remain largely unclear. In this study, we systematically investigate the influence of trace amounts of S (53 and 300 wt ppm) on the ductility of an ultrahigh-purity copper (99.99999%) in the range of room temperature to 900 degrees C. Tensile results show an excellent plastic deformation capacity at any test temperature for the ultrahigh-purity copper, while a remarkable reduction in ductility for both S-containing alloys, particularly at 300-750 degrees C. A microanalysis reveals formation of micro- and nanoscale Cu-S precipitates, mainly distributed at grain boundaries, acting as the nucleation sites for small cavities leading to the crack initiation. This is responsible for the ductility loss in the Scontaining alloys in the whole temperature range. The distinct embrittlement behavior between 300 and 750 degrees C is independent on the crystallographic orientation relationship between the Cu-S precipitates and Cu matrix, but is dominated by the temperature-dependent phase transition behavior of the Cu-S precipitates. Such a structural transformation with the volume expansion accelerates the nucleation and propagation of the microcracks, causing the intergranular embrittlement at intermediate temperatures. Our findings provide a comprehensive experimental understanding on the fundamental mechanisms of impurity-induced the embrittlement in metallic materials.
10.1016-j.msea.2022.143484	-1		Cu-Fe alloy wire with high strength, moderate electrical conductivity and low cost, has a promising application prospect in the electrical industry. In this study, high performance Cu80Fe20 wires were prepared by annealing and drawing at room temperature (RT). Based on the X-ray diffraction and electron microscopy characterization, the influence of microstructural parameters on the mechanical properties and electrical conductivity of the wires were analyzed. The pre-annealing at 500 C, resulted in the nanoparticles precipitation of Cu in Fe-phase and Fe in Cu-phase, respectively. The drawing deformation greatly improved the strength of wires, while did not result in a significant reduction in the electrical conductivity. Cu nanoprecipitation promoted the refinement of the Fe-phase during deformation, which result in a nano lamellar structure of the Fe-phase with an average boundary spacing as low as 50 nm. Dynamic recovery and recrystallization of the Cu-phase were observed to occur during the drawing at RT with the < 112 > texture and annealing twinning. The plasticity and electrical conductivity of the Cu-phase were greatly preserved due to the drawing-induced dynamic recovery and recrystallization. Moreover, the strength of the wire was greatly enhanced by the formation of a nano-lamellar structure in the Fe-phase. Hence, the alloy wire at a strain of 3.94 had a high tensile strength of 863 MPa (125% higher than the original strain-free wire), a total elongation of 5%, and the electrical conductivity reached 47 %IACS (only 8 % IACS lower than the original strain-free wire), which shows higher cost properties than other copper alloys.
10.1016-j.msea.2022.143485	-1		Cu-Al-Ni alloys are one class of typical precipitation strengthening alloy, its mechanical properties are highly sensitive to temperature and strain. In this work, the strength-ductility cooperative effect is investigated through a thermomechanical treatment, i.e., unidirectional cold rolling, Split-Hopkinson-Pressure-Bar deformation, and aging treatment. The results show that a large number of dislocations and twin structures are introduced during Split-Hopkinson-Pressure-Bar deformation motivated by the high strain rate (2.5 x 103 s-1). When the treat-ment temperature is slightly lower than the elongation peak (-28.66%, which almost surpasses all existing Cu-Al-Ni alloys) aging temperature, a high strength (-797.06 MPa) is also achieved. The strength-ductility optimization process mainly includes two mechanisms, twining/grain boundaries optimization, and second-phases optimization, which are closely related to dislocations movement and can contribute together without conflict. In addition, a phase-field-crystal method is used to dynamically display the interaction between twins and dislocations. Finally, the typical characteristics of this kind of high strength-ductility copper alloys are proposed, namely, small grain size, high twin density, and stable grain boundary, providing more space for the cooperative improvement of strength and ductility in Cu alloys.
10.1016-j.msea.2022.143532	-1		In this paper, a series of Cu-3.2Ni-0.6Co-xSi-0.2Cr-0.15 Mg (x = 0.62, 0.75, 0.92 and 1.09) (wt%) alloys were fabricated and subjected to multi-step thermo-mechanical treatment (TMT), and the microstructure and prop-erties of the alloys were investigated in detailed. The results showed that the alloys achieved the combination of high strengths and high conductivity, i.e. yield strengths of 809-913 MPa, tensile strengths of 849-951 MPa, and electrical conductivity of 33.4-42.0 %IACS. The good properties were due to nanoscale delta-(Ni,Co)2Si and Cr3Si precipitates, high-density dislocations, and even deformation twins. More importantly, it is found that the Ni, Co and Cr solute atoms decreased but the Si solute atoms increased with the Si contents in the alloys according to the principle of conservation of mass. For deformation, this change aggravated dislocation annihilation, reduced twinning propensity, and thus weakened the work-hardening effect. For precipitation, this change promoted the coarsening of nanoscale precipitates and the depletion of solute atoms, and thus weakened the precipitation-strengthening effect but benefited the electrical conductivity.
10.1016-j.msea.2022.143576	-1		The orientation relationships between Cr precipitates and matrix in a Cu-Cr-Zr alloy with various aged states were investigated by transmission electron microscopy and High-resolution transmission electron microscopy, and the crystallographic transformations of orientation relationships were also analyzed by stereographic projection and discussed. Four kinds of orientation relationships were detected in the precipitation process of Cu-Cr-Zr alloy, and coexistence of Cr precipitates with Nishiyama-Wassermann relationship and Pitsch relationship was found in the peak-aged Cu-Cr-Zr alloy. The occurrence for cube-on-cube and Pitsch relationship in Cu-Cr-Zr alloy was thought to be caused by the retardation of additions and heterogeneous nucleation of Cr precipitates on dislocations respectively. Transformations of orientation relationships were observed during precipitation and the crystallographic rotation pathways of the transformations were represented by stereographic projection. The interrelationships of various orientation relationships were established by Bain strain and crystal rotation in the Cu-Cr-Zr alloy of this study.
10.1016-j.msea.2022.143693	6	grain; deformation; strain; strength; dislocation; cu-; tensile; size; ecap; grain size; sfe; ductility; hardening; high; stress	Gradient-structured (GS) metals have been reported to possess superior mechanical properties. In this study, the mechanical incompatibility and strain delocalization of Cu-4.5Al-SMAT specimen processed by surface mechanical attrition treatment (SMAT) during tensile was systematically investigated. The results showed that the hardness of specimen exhibited a gradient variation along the thickness after SMAT, which was related to the gradient defects (deformation twins and dislocations). EBSD observation demonstrated that the magnitude of mechanical incompatibility between gradient layers of specimen was associated to the degree of hardness gradient, which was further measured by load-unload-reload (LUR) test. The hetero-deformation induced (HDI) stress of Cu-4.5Al-SMAT specimen was more obvious compared to annealed specimen without SMAT, and the rate of HDI stress strengthening decreased with increasing tensile strain due to the reduction of degree of hardness gradient. Additional strain hardening was found for the Cu-4.5Al-SMAT specimen, which was confirmed by hardness and TEM. Furthermore, the combination of the gradient structure and the coarse-grained matrix can induce dispersed strain bands on the GS surface, which led to strain delocalization and thus obtained high yield strength and considerable ductility in the Cu-4.5Al-SMAT specimen.
10.1016-j.msea.2022.143734	6	grain; deformation; strain; strength; dislocation; cu-; tensile; size; ecap; grain size; sfe; ductility; hardening; high; stress	In order to reveal the effects of cryogenic temperature on the relationship between mechanical properties and recrystallization percentage, the tensile mechanical behaviors of partial recrystallized copper have been investigated by tensile test at 293 K and 77 K, respectively. It is found the yield strength of copper maintains approximate linearity with recrystallization percentage at 77 K and 293 K. Microscopic observations manifested that the deformation twinning was not activated and dislocations slip still dominated plastic deformation at 77 K. Based on the proliferation and annihilation of dislocations, an exponent hardening model was employed to explain the simultaneous improvement of strength and ductility caused by cryogenic temperature.
10.1016-j.msea.2022.143834	-1		Femtosecond laser (fs-laser) micro-machining has been increasingly utilized to efficiently fabricate microscale specimens for mechanical tests. However, the potential damages caused by the fs-laser ablation are still the greatest concerns, making it doubtful whether accurate mechanical properties can be obtained by the fs-laser machined specimens. Herein, the surface roughness and sub-surface microstructure of pure ultra-fine-grained (UFG) and coarse-grained (CG) Cu machined and repeated sidewise polished by fs-laser with optimized parameters are characterized in detail by scanning electron microscopy, confocal laser scanning microscopy, electron backscatter diffraction, and transmission electron microscopy. The results demonstrate that the application of fs-laser beam with a shorter wavelength (343 nm), circular polarization, and lower fluences for cutting and polishing can enhance the cut surface quality (roughness asymptotic to 0.15 mu m without obvious ripples) and effectively remove the damage layer induced by heat effect and plastic dislocation injections. No evident recrystallization or recovery of the dislocation microstructures was detected in the UFG Cu, whereas the dislocation damages were locally observed to extend to a depth below 0.8 mu m in the CG Cu. Microscale tensile tests with samples prepared by the fs-laser machining well reproduce the mechanical responses of the macroscale counterparts, demonstrating the feasibility of fs-laser micro-machining for efficient and reliable mechanical evaluations.
10.1016-j.msea.2022.143847	15	aging; strength; conductivity; electrical conductivity; electrical; mpa; treatment; strengthening; degrees; cu-; cold; precipitation; tensile strength; tensile; iacs	The microstructure evolution and mechanical properties changes of the deformation-aged Cu-20Ni-20Mn alloy during electropulsing treatment (EPT) were investigated. The results indicate that, compared with the deformation-aged Cu-20Ni-20Mn alloy with a tensile strength of 942 MPa and an elongation of 1.4% in the previous study, the tensile strength and elongation of the deformation-aged Cu-20Ni-20Mn alloy after EPT with je (the root-mean-square value of pulse current density) of 10.7 A/mm2 for 150 s increased to 950 MPa and 11.3%, respectively. Fine recrystallized grains, local high density dislocation tangles and local uniformly distributed 9-MnNi phases were found in the microstructure of alloy after EPT, which played a key role in improving the strength and ductility of alloy simultaneously. The 9-MnNi phases distributed in the vicinity of dislocation tangles were more preferentially dissolved into the alpha-Cu matrix under the thermal effect and athermal effect of EPT than the 9-MnNi phases at grain boundaries. The kinetic energy from electron momentum (athermal effect) provided by EPT, which triggered the atomic diffusion accompanied by dislocation movement, leading to the acceleration of recovery, recrystallization processes of alloy and the dissolution of 9-MnNi phases. The results provide guidance for the strength-ductility simultaneous enhancement of various metallic materials.
10.1016-j.msea.2022.143866	-1		Sn macro-segregation and coarse grains easily occur in the conventional casting process of the Cu-15Ni-8Sn alloy with a high Sn content. Here, hot isostatic pressing (HIP), an advanced powder metallurgy technique, was introduced to explore feasibility in alleviating or eliminating such defects. The gas-atomized powder with high homogeneity of composition was used, which was solidified rapidly. The microstructural evolution, mechanical properties, deformation mechanisms and strengthening mechanisms were deeply and systematically revealed and discussed. Nearly fully dense samples were fabricated by HIP with no Sn macro-segregation, and simulta-neous strength-plasticity enhancement was obtained. The content of harmful discontinuous precipitation col-onies was controlled to only-3.11 vol%. This was attributed to the fine grain size of the powder and the preferential complete recrystallization process during the HIP. That is, the gamma nucleation sites were occupied by numerous grain boundaries provided by fine grains, and the driving force of gamma growth was consumed by recrystallization. Furthermore, enhanced mechanical properties were related to the Sn macro-segregation sup-pression, grain refinement (-11.0 mu m), dislocation density continuous increase, and dispersion distribution of gamma precipitates, etc. These encouraging findings validate the advantages and potential of HIP in the fabrication of Cu-15Ni-8Sn alloy with enhanced mechanical properties for structural applications.
10.1016-j.msea.2022.143915	15	aging; strength; conductivity; electrical conductivity; electrical; mpa; treatment; strengthening; degrees; cu-; cold; precipitation; tensile strength; tensile; iacs	Cu-Ti alloys were prepared by accumulative roll bonding-deformation diffusion (ARB-DD) process. The deformation-aging behavior and the evolution of microstructure and properties were studied, and the intrinsic mechanism was revealed. The results show that multi-scale substructures such as Taylor lattices formed inside Cu-Ti alloys in ARB-DD process. They provide sites for the formation of Cu4Ti during the subsequent deformation-aging process, and promote homogeneous nucleation of a high density of spherical coherent Cu4Ti particles. The strong ordering effect during the interaction between Cu4Ti and dislocations hinders the dislocation motion. As a result, the ultimate tensile strength (UTS) of secondary deformation-aged Cu-Ti alloy is nearly 1040 MPa, which is about 160% higher than that of Cu-Ti alloy before deformation-aging treatment. The increased content of Cu4Ti particles and the decreased low-angle grain boundaries (LAGBs) reduce the degree of electron scattering, thereby resulting in an electrical conductivity of about 13% IACS, which is about 90% improvement over alloys before deformation-aging treatment.
10.1016-j.msea.2022.143948	-1		Simultaneous improvement of both the strength and electrical conductivity of Cu-Fe alloys (CFAs) through the conventional casting method is an extremely challenging task. In this study, an attempt was made to overcome this issue via preparing CFAs with ultrafine alloy powders embedded with nano Fe particles. Ultrafine CFA powders with various Fe contents ranging from 5 to 50 wt% were synthesized by a novel rapid solidification route, namely, gas-water combined atomization (GWA) process. The alloy powders prepared via GWA were then processed by pressureless sintering, hot rolling, annealing, and cold rolling. The microstructure evolution, me-chanical properties, and electrical conductivity of CFAs were comprehensively investigated. The average size of Cu grain and Fe particles in all sintered CFAs was smaller than 3 and 2 mu m, respectively. The grains of sintered CFAs were obviously refined by the Fe particles, and the addition of Fe inhibited the formation of Cu twins. After rolling, the Fe particles elongated and became fibrous along the rolling direction. The degree of formation of fibrous Fe enhanced with the increase of Fe content. Cold-rolled CFAs with 5-50 wt% Fe exhibited the tensile strength of 560-1250 MPa and conductivity of 33-65% IACS, indicating that CFAs in this study achieved su-perior mechanical and electrical properties. The microstructure evolution and strengthening mechanisms of CFAs were described. These findings can provide new insights into the powder metallurgy manufacturing of high-performance CFAs.
10.1016-j.msea.2022.143957	-1		This study deals with the evolution of strength and microstructure in Cu-20Ag alloy during wire drawing from an initial diameter of 7.84 mm-0.02 mm. The final wire had a strength of 1670 MPa and 53.8% of the conductivity of international annealed copper standard (IACS). Electron backscattering diffraction (EBSD) and transmission electron microscope (TEM) were used for microstructural characterization in the later stages of deformation, we found that many boundaries resulting from the lamellar structures and the occurrence of nano-twins formed in the lamellar improved the strength of the wire. When the wire diameter is less than 2.95 mm,with an essentially constant dislocation density, the strength can be related solely to strengthening boundaries by a grain size refinement. The strengthening mechanism of the wire during cumulative strain is discussed.
10.1016-j.msea.2022.144131	-1		Nanoporous coppers (NPCs) with ligament size down to 800 nm and relative densities ranging from 15.7% to 47.5% were synthesized by vapor phase dealloying (VPD) Cu33Zn67, Cu16Zn84, and Cu6Zn94 precursor alloys. The ligament size of NPCs could be adjusted by applying different VPD temperatures under high vacuum, while the change in the mechanical properties of NPCs were monitored by compression tests. Although NPCs possessed a random ligament structure, the energy absorption capability of NPCs was up to 183.3 MJ/m3, which is an order higher than that of other Cu foam structures fabricated by different methods such as 3D printing, electron beam melting, electro-deposition, chemical dealloying and friction powder compaction. High apparent relative density and ligament connectivity could effectively transmit the compression energy in the form of stress waves, and therefore had higher densification strain and better energy absorption capacity. With the use of corrected Gibson and Ashby scaling equation, the ligament strength of NPC was up to 3456 MPa, which was ten times higher than that of bulk Cu and comparable to that of other ordered or periodic copper foams.
10.1016-j.msea.2022.144159	15	aging; strength; conductivity; electrical conductivity; electrical; mpa; treatment; strengthening; degrees; cu-; cold; precipitation; tensile strength; tensile; iacs	In comparison to other Cu-based alloys, the high-temperature strength of the studied Cu-4.06Cr-1.25Nb alloy fabricated by the atmospheric melting method was improved significantly. After homogenization at 950 degrees C for 4 h, hot rolling by 80%, solid solution treatment at 940 degrees C for 4 h, cold rolling by 50%, and aging at 400 degrees C for 2 h, the tensile strengths of the Cu-4.06Cr-1.25Nb alloy fabricated by spark plasma sintering (SPS) at 20 degrees C, 400 degrees C, 450 degrees C, and 500 degrees C were 535 MPa, 256 MPa, 212 MPa, and 165 MPa, respectively. While they were lower than the alloys fabricated by atmospheric melting at high temperatures, such as at 400 degrees C (285 MPa), 450 degrees C (266 MPa), and 500 degrees C (230 MPa), which could be explained by the grain boundaries strengthening of refined grains. At room temperature, the studied alloy fabricated by SPS had many refined grains, resulting in high tensile strength . However, the grain-refined/coarsened boundaries became the crack sources and the crack propagation paths, which were not conducive to the high-temperature strength . These findings are helpful in developing high heat-resistant Cu-Cr-Nb alloys.
10.1016-j.msea.2022.144221	-1		Basing on the concept of processing rote design and the compositional design, a good combination of strength and ductility in a Cu-9Ni-6Sn-0.2Nb alloy was successfully achieved by the combination of Nb addition, pre-annealing and the subsequent aging treatment. The microstructure evolution, mechanical properties and elec-trical conductivity on the Cu-9Ni-6Sn alloys with Nb addition were investigated in details. The results indicated that NbNi3 particles efficiently suppressed the growth of recrystallized grains in the Cu-9Ni-6Sn-0.2Nb alloy and fined grains were achieved during pre-annealing treatment, the grain size being refined from-49.5 mu m to-2.5 mu m. After aging treatment, an optimal combination of ultimate tensile strength 1000 MPa, yield strength 825 MPa, elongation 13%, Vickers hardness 300 HV and electrical conductivity 13.1 %IACS were attained in the Cu-9Ni-6Sn-0.2Nb alloy by 80% cold-rolling, pre-annealing at 850 degrees C for 3 min and aging at 350 degrees C for 10 h . Especially a good strength with excellent elongation was firstly achieved in Cu-Ni-Sn alloys via the combination of Nb addition, pre-annealing and aging treatment in this study. Strengthening mechanism has been quantita-tively established, indicating that the grain boundary and precipitation strengthening play important roles in enhancing the yield strength of the alloy with Nb addition. This study aims to provide a new insight into improving the comprehensive properties of Cu-Ni-Sn alloys, and supplies basis for the microstructure and mechanical property control of the materials.
10.1016-j.msea.2022.144328	-1		It is urgent to develop new copper alloys for future fusion reactors (e.g. DEMO and CFETR). This work involved the design and fabrication of an alloy, Cu-0.8Cr-0.12Zr-(0.05Si), with increasing high-temperature softening resistance by thermo-mechanical treatment. The influence mechanism of Si on its mechanical properties and softening resistance at high temperature was investigated. The peak-aged Cu-Cr-Zr alloy containing Si exhibits higher ultimate tensile strength of 622 MPa, yield strength of 588 MPa with a considerable elongation of 17% and electrical conductivity of 76% IACS. The dislocation and Orowan strengthening trigged for finer Cr precipitates are proven to be the main reasons for the improvement in strength . Moreover, the increase in elongation originates from the deformation twins due to the lower stacking fault energy, as confirmed by the first principles. Meanwhile, the addition of Si can significantly improve the high-temperature softening resistance of the alloy. The main reason is that the growth of Cr precipitates is suppressed by adding Si, and its pinning effect on the boundary is better, thereby inhibiting the occurrence of recrystallization.
10.1016-j.msea.2022.144340	15	aging; strength; conductivity; electrical conductivity; electrical; mpa; treatment; strengthening; degrees; cu-; cold; precipitation; tensile strength; tensile; iacs	A new dual-scale (submicron and nanoscale) FeCrSi ternary second-phase has been successfully constructed in designed Cu-2.5Fe-0.3Cr-0.2Si alloy. The synergistic addition of Cr and Si promotes the transformation of the submicron Fe phase morphology from square to flower shape in as-cast alloys. The orientation relationship between nanoscale FeCrSi phase and Cu matrix is: [011] Cu//[011] Fe11CrSi4 and the misorientation angle be-tween the (200) of the Cu matrix and the (022) of the Fe11CrSi4 phase is about 4 degrees. After three-stage thermo-mechanical treatment, the tensile strength and electrical conductivity of the alloy are 435 MPa and 70.52 %IACS, respectively. According to the calculated results, precipitation strengthening and substructure strengthening play an important role in the strengthening of Cu-Fe-Cr-Si alloys. With the addition of Cr and Si, the precipitation of the second phase in the alloy is promoted, which also leads to the improvement of the electrical conductivity and mechanical properties of the alloy.
10.1016-j.msea.2022.144412	3	sma; shape; shape memory; memory; smas; superelastic; bars; damping; cu-al-mn; mechanical; bending; applications; numerical; sma bars; material	The effects of the scan vector rotation angle in adjacent layers during laser powder bed fusion of a Cu71.6Al17Mn11.4 (at%) shape memory alloy on the porosity, microstructure, transformation temperatures, as well as superelastic properties, were investigated. To explore the influence of the applied scanning strategy, a bidirectional stripe hatching was employed by utilizing 0 degrees, 25 degrees, 50 degrees, 79 degrees and 90 degrees rotation of the scanning di-rection in adjacent layers. Changing the scan vector rotation had no apparent effect on the characteristics of porosity. The scan vector rotation allowed a manipulation of the microstructure (grain size, texture) to some extent which was evaluated via electron backscattered diffraction (EBSD) analysis. While the size and distri-bution of grains only showed negligible differences, a more pronounced change in the texture as well as in the grain misorientation has been observed. A significant recoverable strain difference for the applied scan vector rotations was observed as a result of compressive loading-unloading tests. The samples produced with 90 degrees scan vector rotation exhibited 6.05% recoverable strain under 8% applied strain, whereas only minor recoverable strain values (around 1.4%) were obtained in the specimens produced without a shift in the scan vector rotation (0 degrees). Other vector rotations (25 degrees, 50 degrees, 79 degrees) resulted in a moderate superelastic performance with respect to the 90 degrees-samples. These findings clearly show that polycrystalline Cu-Al-Mn shape memory parts with high shape-recovery rates can be directly fabricated using laser powder bed fusion and an adjusted scanning strategy. Thus, this approach can serve as a general tool to optimize or control superelasticity in additively manufactured Cu-based SMAs.
10.1016-j.msea.2022.144464	-1		Impact toughness at ambient and cryogenic temperatures was investigated with systematic fracture analyses for CuFeMn and Al15(CuFeMn)85 (at%) immiscible medium-entropy alloys. These two types of alloys exhibited different impact toughness behavior at different temperatures, while exhibiting higher impact toughness values than those of dual-phase steels with a similar strength level.
10.1016-j.msea.2022.144474	-1		In this work, cold drawing deformation was applied aiming to achieve a good combination of strength and electrical conductivity of Cu-20Fe alloy, and also such underlying mechanisms for microstructure evolution and strengthening, as well as variation in conductivity were clarified. It is also found that both Cu matrix grains and Fe-rich dendrites can be significantly refined and transformed into fibrous structure with increasing of drawing strain. The average size of Cu grains and thickness of Fe fiber are 0.47 +/- 0.05 mu m and 25 +/- 5 nm, respectively for alloy subjected to the drawing strain of eta = 5.78. In addition, the Fe dendrites exhibit a strong <110> fiber texture, while the corresponding Cu matrix forms a <111> fiber texture. It is demonstrated that the excellent properties with the yield strength of 1173 MPa and the electrical conductivity of 41 %IACS can be reached for cold-drawn Cu-20Fe alloy. In addition, the quantitative analysis on strengthening contributions shows that the high strength of as-drawn Cu-20Fe alloy is dominantly originated from high-density Fe fibers. Meanwhile, the lower electrical conductivity is ascribed to the high solute Fe content and high-density Cu/Fe heterogeneous phase interface.
10.1016-j.msea.2022.144478	-1		In this work, Cu-Ti-Ni-Si-diamond (Di) composites were successfully prepared by casting method based on Ti-Si-C system. The microstructures and properties of the prepared Cu-3.57Ni-1.8Ti-0.85Si-1Di composites were investigated. It is found that, besides core-shell Di@TiC particles formed by Ti-Di reaction, the Ni16Ti6Si7 phase will be formed prior to other Ni-Si phases during both casting and aging treatment processes. The morphologies of the aging precipitated Ni16Ti6Si7 depend on the concentration of Ni, Ti and Si solutes in the Cu matrix. If the concentration of the Ni, Ti and Si solutes is low, the needle-like Ni16Ti6Si7 with a large aspect ratio will be precipitated. On the contrary, when sufficient Ni, Ti and Si are dissolved in the Cu matrix, the Ni16Ti6Si7 will be changed from a needle-like phase to a spherical phase. The hot rolling can promote the solid solution of the dendritic Ni16Ti6Si7 formed during casting, and make the Ni16Ti6Si7 easier to precipitate in a spherical shape. As a result, the Cu-Ni-Ti-Si-Di composites will have excellent comprehensive properties after rolling, solution and aging treatment. The tensile strength of the Cu-3.57Ni-1.8Ti-0.85Si-1Di can get to 702.2 MPa with the elongation of 3.5% and the hardness of 291.1HV. At the same time, the conductivity is kept at 40%IACS.
10.1016-j.msea.2023.144581	6	grain; deformation; strain; strength; dislocation; cu-; tensile; size; ecap; grain size; sfe; ductility; hardening; high; stress	An anisotropy Cosserat continuum model is established for nanotwinned copper by introducing the special orientation relationship between the twin and the matrix. The anisotropy effect induced by the difference in crystal orientation and the strain gradient effect induced by the inhomogeneous deformation between the twin and the matrix in grains are considered. The results obtained by the model with the same parameters of the anisotropy Cosserat elastoplastic constitutive have a good agreement with stress-strain curve of nanotwinned copper collected over different experimental studies with varying twin thickness from 15 nm to 100 nm and coarse grain copper (CG-Cu) with micron level grain size. The effect of twin spacing, twin thickness and preferred orientation on the mechanical performance of nanotwinned copper, such as yield strength, elastic modulus and hardening exponent is systematically studied based on the proposed model. Our results show that the anisotropy effect mainly affects elastic modulus and yield strength, the strain gradient effect affects yield strength and strain hardening rate. The results also demonstrated that appropriate preferred orientation and twin spacing of the nanotwinned copper could make the stress softening or uniform stress distribution by the coordinated deformation between different nanotwinned structures.
10.1016-j.msea.2023.144603	-1		Cu-10Fe composites were produced by the vacuum suction casting and traditional vacuum mold casting, respectively. The evolution of microstructure and properties of the composites during cold rolling and aging processes was analyzed. Compared with the traditional mold-casted Cu-Fe composites, the suction-casted Cu-Fe composite had better mechanical properties, with microhardness, tensile strength and elongation of 146 HV, 526 MPa and 23.7%, respectively. The softening temperature of the suction-casted Cu-Fe composite was 520 degrees C, which was 220 degrees C higher than that of traditional mold-casted Cu-Fe composite. The good performance of the suction-casted Cu-Fe composite was mainly attributed to the refinement of the Cu matrix and the formation of the multi-scale alpha-Fe particles caused by the effect of solute trapping during vacuum suction casting. The yield strength of the composites was mainly attributed to the contribution of Orowan strengthening, refinement strengthening and dislocations strengthening, which count for 31.1%, 25.8% and 24.1%, respectively.
10.1016-j.msea.2023.144689	-1		A superior comprehensive property of Cu-Ni-Si-Al2O3 alloy, including microhardness of 184.4 HV, yield strength of 573 MPa, tensile strength of 607 MPa, and excellent electrical conductivity of 54.9 %IACS, is obtained with the minute addition of alloying elements (similar to 0.75 wt% Ni and similar to 0.20 wt% Si) and nanometer scaled Al2O3 particles. The influence of these Al2O3 particles on the precipitation process and strengthening behaviors has been investigated by the scanning electron microscopy (SEM) equipped with electron-backscattered diffraction (EBSD) and transmission electron microscope (TEM). The results show that the addition of nanometer scaled Al2O3 particles can cause the increase of dislocation density and refinement of the grains during cold deformation and the following aging process. The precipitation kinetics are consequently promoted due to heterogeneous nucleation around the dislocations, sub-grain and grain boundaries and the Al2O3 particles, resulting in the improvement in distribution and refinement of precipitation. The volume fraction and number density of the precipitates are increased, resulting in the simultaneous enhancement of mechanical and electrical properties in the Cu-Ni-Si-Al2O3 alloy. This study provides a significant guidance for the design of precipitation hardening copper alloy, by introducing the precipitation strengthening and dispersion strengthening.
10.1016-j.msea.2023.144866	7	irradiation; shear; grain; ta; deformation; size; radiation; voids; nanocrystalline; simulations; similar; void; temperature; irradiated; boundaries	Nanometer size grains, solid solution strengthening, low temperatures, and a high density of nanotwins can provide significant strengthening to a material. Nevertheless, under loading the microstructure may evolve altering the effect of grain size, twin density, etc. on this strengthening. In some cases, these effects can be coupled as in detwinning, which is a mechanism for cryogenic grain growth . In this work, a series of copper nanotwinned columnar grains are solid solution alloyed with aluminum and subject to ambient and cryogenic (-196 degrees C) environments during mechanical indentation, with the influence of alloying on the detwinning evolution studied. Under indentation, at a lower aluminum solute content (2 at%), the columnar grains bent corresponding to a loss of twins. At a higher aluminum solute content (8 at%), the grains shear and retain the nanotwins. Atomistic-scale simulations reveal an increase in the incoherent twin boundary velocity with decreasing temperature, but this boundary velocity is reduced with increasing alloy solute content. The coupling of solid solution strengthening and nanotwin stabilization is then used to explain the microstructural stability as a function of indentation at different temperature conditions.
10.1016-j.msea.2023.144925	-1		In this work, the aging temperature effects on microstructures, mechanical, and damping properties of Cu-11Al-5Mn-0.7Ti-1Ta were investigated. The outcomes indicated aging can effectively enhance both mechanical and damping properties, and the optimum aging temperature of 400 degrees C was obtained. The associated microstructural changes caused by the precipitated phase after aging resulted in an increase in tensile strength from 386.1 MPa to 631.5 MPa, an increase of 63.5% compared to the original alloy. Meanwhile, the room temperature damping value increased from 0.026 to 0.0581, which was increased by 123.5%. The damping strengthening mechanisms were discussed mainly from the perspective of the change in motionable interface and dislocation behavior induced by precipitated phase after aging treatment. The results in this paper provide a new reference for simultaneously improving mechanical and damping behaviors of Cu-Al-Mn based alloys.
10.1016-j.msea.2023.144983	-1		One of the major challenges in welding the Cu-Cr-Zr alloys is that the high welding temperature often causes the coarsening of the precipitates, resulting in lower joint strength . Various strategies were studied to reduce the welding temperature below the aging temperature for limiting the precipitate coarsening. The results showed that great challenges existed in reducing the friction stir welding (FSW) temperature below the peak-aging temperature of Cu-Cr-Zr alloy (420-480 degrees C) without using coolant. Through softening the Cu-Cr-Zr alloys to the supersaturated solid solution state prior to FSW, the peak temperature during FSW of Cu-Cr-Zr alloy under water was reduced to similar to 481 degrees C, which is close to the aging temperate of the Cu-Cr-Zr alloy. After post-weld aging heat treatment, the stir zone exhibited higher hardness than the peak-aged Cu-Cr-Zr alloy due to the combination of the high density of precipitates 10.5 nm in diameter and refined grains 0.65 mu m in diameter, enabling the achievement of high joint strength equal to the peak-aged base metal. In addition, the FSW zone also exhibited a high electrical conductivity of 88.9% IACS, which is higher than that of the peak-aged base material (81.0% IACS).
10.1016-j.msea.2023.144997	-1		Nanostructured metallic materials often lack sufficient work-hardening capability and suffer premature necking during tensile loading. In this study, intense rolling strain was applied to process nanocrystalline CuAg sheet, and aging treatment was designed to further tailor the microstructure and properties. Features of grains, Ag precipitates and short-range ordered (SRO) structure were characterized by transmission electron microscope (TEM). Superior tensile strength of 600 MPa, uniform elongation of 10% and electrical conductivity of 86.7% IACS were successfully achieved. Mechanisms for the balanced mechanical and electrical properties were analyzed.
10.1016-j.msea.2023.145000	-1		We investigated the microstructures of equal channel angular extrusion (ECAE) processed sintered composites of copper (Cu) and tantalum (Ta). These composites were produced with nominal Ta volume percentages ranging from 25% to 75%. Additional composites of the same nominal Ta content were prepared with a minor amount of titanium (Ti) added to facilitate interphase bonding. Ti addition was found to markedly improve the strength and co-deformability of the composites, allowing reliable extrusion of Cu-Ta composites with novel microstructures. A major influence of the Ti appears to be to soften the Ta, which contributes to improved co-deformability by reducing the flow stress mismatch between the composite constituents. A change in the fracture surface morphology in the Ti-modified composite compared to the unmodified composite suggests that the Ti may also improve cohesion between Cu and Ta by reducing Ta surface oxides.
10.1016-j.msea.2023.145092	-1		In this study, we enhanced both hardness and electrical conductivity in solution-treated Cu-0.66Cr-0.05Zr (at%) wires. After cold deformation, hardness increased by similar to 100%, and electrical conductivity increased by 24%. We further demonstrated that post-deformation aging increased hardness by another 27%-38% and electrical conductivity by up to an additional 80%. In previous research on composite conductors, hardness increase by deformation was usually accompanied by a decrease in electrical conductivity. But we were able to increase both simultaneously by controlling thermo-mechanical process parameters to engineer precipitate size and density. We attributed our simultaneous enhancement of hardness and conductivity to the generation of deformationinduced, disc-shaped, and semi-coherent precipitates with thicknesses less than a nanometer. Aging-induced precipitates remained only a couple of nanometers thick, but their Cr content (1.2-8.4 at%) was relatively greater than that of deformation-induced precipitates. We subjected solution-treated materials to either aging followed by deformation or deformation followed by aging. Our results were the same regardless of order.
10.1016-j.msea.2023.145126	6	grain; deformation; strain; strength; dislocation; cu-; tensile; size; ecap; grain size; sfe; ductility; hardening; high; stress	The effect of cold working by drawing, rolling, or equal channel angular pressing (ECAP) on the microstructure, the texture, the mechanical properties, and the electrical conductivity of a Cu-0.25%Mg alloy was investigated. The plastic deformation led to the development of continuous dynamic recrystallization that was accompanied by strain-induced low-angle boundary formation and their transformation into high-angle boundaries with straining. The elongated grains evolved after drawing. Sheet rolling provided pancaked ultrafine grain formation assisted by the development of microshear bands. After ECAP almost equiaxed ultrafine grains formed readily inside the deformation microbands. The rapid kinetic of grain refinement assisted by geometric dynamic recrystallization during cold rolling and drawing led to the formation of ultrafine grains with transverse sizes of about 0.20 & mu;m and 0.43 & mu;m, respectively, while the grain size in the ECAP samples was 0.88 & mu;m after total strain of 4. The deformation microstructures led to the significant strengthening resulting in the ultimate tensile strength of about 670 MPa after drawing or rolling to total strain of 4 and 625 MPa after ECAP to total strain of 9.2. Elongation slightly decreased from 21% to 19% after ECAP and dramatically degraded to 6-8% after drawing or rolling. A decrease in elongation was accompanied by a linear increase in the fraction of specific texture components. Electrical conductivity gradually decreased by about 6-10% IACS with straining regardless of deformation method. The strengthening mechanisms and the conductivity variation during deformation are discussed.
10.1016-j.msea.2023.145196	15	aging; strength; conductivity; electrical conductivity; electrical; mpa; treatment; strengthening; degrees; cu-; cold; precipitation; tensile strength; tensile; iacs	The recently introduced concept of additive manufacturing + can be used to prepare parts with complex shapes and also high-performance alloys. In this paper, Cu-15Ni-8Sn alloys were prepared by laser powder bed fusion (L-PBF) and laser-directed energy deposition (L-DED), and successively solutionized, 80% cold-rolled, and aged at 400 degrees C. This unconventional process increased the yield strength of L-PBF and L-DED specimens to 1389 MPa and 1317 MPa, with a considerable elongation of 1.9% and 2.8%, respectively. It also greatly shortened the preparation process compared with other methods. The microstructural and mechanical changes of L-PBF and L-DED samples undergone the same pre-deformation aging treatment are consistent. It implies that the pre -deformation aging strengthening mechanism of two kinds of printed samples is basically the same. Pre -deformation changed the morphology and distribution of the spinodal structures and ordered phases, and pro-moted the nucleation of discontinuous precipitates (& gamma;-D03 phase) that preferentially precipitated along elongated grain boundaries and shear bands. This weakened the strengthening effect of D022 and γ′ ordered phases. Pre -deformation expedited the aging process, but this was accompanied by a drop in the aging strengthening effect and was more sensitive to the aging temperature. In addition, the stacking faults and L-C dislocations along dislocation cell walls coexisted with the ordered phases for a long time, which inhibited the nucleation of the & gamma; phase and produced a good strengthening effect.
10.1016-j.msea.2023.145210	10	composites; nanoparticles; strength; matrix; high; strengthening; particles; conductivity; composite; electrical; mpa; sintering; ods; grains; mechanical	An ultra-high strength TiZrNbTa (TZNT) high-entropy alloy (HEA) with good plasticity was attempted as a new reinforcing phase, which is introduced in the highly conductive Cu matrix to fabricate high-strength conductive composites. This work utilized a combination of a two-step ball milling method (first HEA mechanical alloying followed by fabrication of TZNT HEA/Cu hybrid powder) and a spark plasma sintering process to prepare the bulk TZNT HEA/Cu metal matrix composites (MMCs). Remarkably enhanced mechanical properties of the designed TZNT HEA/Cu MMCs with increasing TZNT contents were characterized while the electrical conductivity declined. Compared to the strength of the copper matrix, the strength of the fabricated 50 wt% TZNT/Cu specimens increased up to 340% induced by the second phase strengthening effect. The combination of grain boundary strengthening and dislocation strengthening contributed relatively less to the overall strength improvement of the composites. The TZNT/Cu composites were found to be a new insight into the high-strength conductive material preparation by choosing TZNT HEA with superior strength as hard secondary phase in copper matrix.
10.1016-j.msea.2023.145222	-1		Copper alloys fabricated by laser powder bed fusion (LPBF) have been widely utilized in a diverse range of industrial sectors, including electrical, electronics, aerospace, etc. This study centers on an LPBF-fabricated insitu precipitation-hardening Cu-1.8Cr-1.0Nb-2.0Fe copper alloy and comprehensively investigates its densification, microstructure, mechanical properties, strengthening mechanisms, and coarsening resistance. The results demonstrate that optimal process parameters enable the fabrication of nearly full specimens with a relative density (RD) of 99.98%. The microstructure of the as-built (AB) and direct aging (DA) treatment specimens consists of columnar grains. During the LPBF process, an Nb(FeCr) core-shell nanostructure in-situ precipitates, inducing a strong precipitation effect that results in an exceptional ultimate tensile strength (UTS) of 444 MPa. After aging treatment, the average radius and volume fraction of the Nb(FeCr) core-shell nanostructure remains unchanged. Another reinforced phase of FeCr & sigma;-phase forms to further enhance the tensile strength, resulting in a higher UTS of 498 MPa for DA specimens. Precipitation strengthening is the dominant mechanism among the four strengthening mechanisms for both AB and DA specimens. The excellent coarsening resistance of Nb(FeCr) core-shell nanostructure is confirmed by (i) the almost unchanged size and volume fraction after aging treatment and (ii) the close contribution value of precipitation strengthening induced by Nb(FeCr) core-shell nanostructure to YS for AB and DA specimens. This study provides valuable insights into the in-situ precipitation behavior for LPBF-fabricated copper alloys.
10.1016-j.msea.2023.145239	-1		Cryorolling is introduced to achieve synergetic improvement in the strength and ductility of heterostructured copper/brass laminates. The cryorolled laminates consist of fibrous elongated ultrafine grains, curved interface, and high density of shear bands and deformation twins. After low-temperature annealing, the multistage heterostructure is formed, which contributes to superior mechanical properties.
10.1016-j.msea.2023.145251	-1		Cu powders, conformally coated with Hf, were used as a precursor for fabricating a bulk Cu-Hf nanocrystalline alloy by mechanical alloying. The resultant specimens were plastically deformed at ambient and elevated temperatures. The Cu matrix is nanocrystalline and contains a nanoscale, monoclinic HfO2 precipitate dispersion. Despite the plastic deformation, the microstructure did not coarsen. However, the alloy began accommodating deformation by grain boundary mechanisms at much lower temperatures than other stabilized, nanocrystalline Cu-based alloys. This behavior is attributed to the incoherency of the HfO2 precipitates with the Cu matrix, highlighting the importance of coherency of the stabilizing precipitate with the matrix as well as the phase change(s) that stabilizing solutes may have in the presence of contaminates.
10.1016-j.msea.2023.145396	1	shape; memory; shape memory; damping; martensite; martensitic; damping capacity; transformation; capacity; strain; superelasticity; temperature; cu-al-mn; shape memory effect; effect	The spheroidization of lamellar Fe3C in pearlite in steels can significantly increase the plasticity. Inspired by the fact, we proposed that to introduce ductile spherical a phase with precipitates of lc phase by Fe alloying can realize not only better shape memory effect (SME) but also higher mechanical properties than to introduce the blocky a phase does in Cu-based alloys. To confirm our idea, the effects of two annealings in two-phase region were studied on the spheroidization of a phase and precipitation of lc phase and the resultant SME and mechanical properties in a Cu8.5Al9.6Mn3.2Fe alloy. Our results showed that the two annealings could simultaneously spheroidize the a phase and precipitate the lc phase in the alloy. The alloy with the spherical a phase showed-1% higher recovery strain and-8% higher fracture strain than the alloy with the blocky a phase did. The spheroidization of a phase together with the precipitation of lc phase will be a direction for developing ductile Cu-based alloys with better SME and higher strength .
10.1016-j.msea.2023.145432	-1		In this work, a Cu-Cr-Ag-Mg-Sn alloy was developed assisted by a CALPHAD technique, by which a suitable chemical composition (Cu-0.5Cr-0.1Ag-0.05Mg-0.05Sn) and processing parameters were efficiently designed. The achieved alloy exhibited yield strength and conductivity values of 642 MPa and 74.2% IACS, respectively, which greatly surpassed the commercial C18150 alloy. Transmission electron microscopy observation demonstrated that such a good comprehensive performance was attributed to numerous nano-scale Cr precipitates that possessed a strong coherent relationship with the Cu matrix. Further microstructure characterizations demonstrated that these beneficial Cr precipitates were associated with subgrain boundaries in the alloy introduced by a cold-rolling & RARR;short-time secondary solid solution. Atom probe tomography analysis demonstrated that Sn atoms that readily attached to the surfaces of Cr precipitates.
10.1016-j.msea.2023.145453	15	aging; strength; conductivity; electrical conductivity; electrical; mpa; treatment; strengthening; degrees; cu-; cold; precipitation; tensile strength; tensile; iacs	The effect of the multi-stage thermo-mechanical treatment on the microstructure and properties of a Cu-2Fe-0.5Ti alloy (wt%) was investigated. After repeated thermos-mechanical treatment, the alloy has the yield strength, tensile strength, elongation, electrical conductivity and softening temperature of 521 MPa, 554 MPa, 5.9%, 70.4 %IACS and 550 degrees C, respectively. The nano-scale Fe2Ti and & gamma;-Fe precipitates, accompanying with some submicron-scale primary Fe2Ti phase, are found in the aged alloy. The orientation relationship between the nano-scale Fe2Ti precipitate and the Cu matrix is Fe2Ti [1 21 6]//Cu [01 1] (with a small deviation) and Fe2Ti (02 21)//Cu (200), while that between the nano-scale & gamma;-Fe precipitate and the Cu matrix is & gamma;-Fe [110]//Cu [110] and & gamma;-Fe (111)//Cu (111), respectively. The precipitation of Fe2Ti and & gamma;-Fe phase contributes to the improvement of the electrical conductivity and mechanical properties of the alloy. The strengthening mechanisms of the designed alloy is mainly grain boundary strengthening, dislocation strengthening and precipitation strengthening.
10.1016-j.msea.2023.145475	1	shape; memory; shape memory; damping; martensite; martensitic; damping capacity; transformation; capacity; strain; superelasticity; temperature; cu-al-mn; shape memory effect; effect	A copper-based shape memory alloy Cu-11.85Al-3.2Mn-0.1Ti with desirable superelasticity and shape memory effect was printed by laser powder bed fusion (LPBF), which demonstrated the feasibility of engineering applications through the deformation and recovery of complex corrugated structural components. The microstructure of LPBF-printed Cu-11.85Al-3.2Mn-0.1Ti was composed of full beta(1)' martensite with a high density of stacking faults and twin crystals. The abnormal phase constitution of full martensite in the printed Cu-11.85Al-3.2Mn-0.1Ti is correlated to substrate preheating and thermal cycling during LPBF. The start and finish transformation temperatures of martensite (M-s and M-f) and austenite (A(s) and A(f)) were 172.5 degrees C, 144.4 degrees C, 180.2 degrees C and 209.2 degrees C, respectively. The printed samples exhibited compressive strength of 1319 MPa with a compressive fracture strain of 16.1%. The printed alloy displayed remarkable superelasticity and shape memory effect. The superelastic recovery rate reached a maximum value of 87% at 6% pre-strain, corresponding to a superelastic recovery strain of 5.22%. The mechanism of superelasticity is attributed to the rubber-like deformation behavior. Moreover, the pre-strained samples demonstrated a desirable shape memory effect under the temperature stimulation, where the shape memory recovery rate of up to 100% at a pre-strain of 6%, corresponding to a shape memory recovery strain of 0.78%. The reasons for the favorable shape memory effect were: (i) the thermoelastic inversion of martensitic transformation and (ii) the precipitation of gamma(2)(Cu9Al4) phase along the grain boundaries. As a result, these findings suggest that the LPBF technique can produce Cu-Al-Mn-Ti parts with superelasticity and good shape memory properties, which provided valuable references for printed copper-based shape memory alloys with full martensitic structures.
10.1016-j.msea.2023.145510	15	aging; strength; conductivity; electrical conductivity; electrical; mpa; treatment; strengthening; degrees; cu-; cold; precipitation; tensile strength; tensile; iacs	A new strategy for the preparation of Cu-Fe alloy with excellent comprehensive performance is proposed. This strategy combines the construction of dual-scale polymetallic second phases with the addition of trace solid solution atoms. A series of Cu-2Fe-0.3Cr-0.2Si-xMg (x = 0.1, 0.3, 0.5) alloys are designed and prepared through multi-stage thermo-mechanical treatment. Among the reported Cu-Fe alloys with low Fe content (Fe content less than 3 wt%), the designed Cu-2Fe-0.3Cr-0.2Si-0.3 Mg alloy has the highest product of the tensile strength times the electrical conductivity (PSC). The tensile strength and PSC of the Cu-2Fe-0.3Cr-0.2Si-0.3 Mg alloy are 698 MPa and 43.9 GPa & BULL;%IACS, respectively. The dual-scale polymetallic second phase has been successfully constructed. The submicron-scale Fe8CrSi phase triggers the generation of substructures, such as geometrically necessary dislocation boundaries in lamellar structures and random dislocation boundaries in cell shapes. The high-density low angle grain boundaries (LAGBs) of substructure evolution enhances the substructure strengthening of the alloy. The main strengthening phase in precipitation strengthening is the nanoscale Fe11CrSi4 phase. An appropriate amount of Mg reduces the ultimate solid solubility of Fe atoms in Cu alloys, promotes the formation of a dual-scale second phase and refines the grain size of the alloy. Therefore, the comprehensive performance of the design alloy is significantly improved.
10.1016-j.msea.2023.145610	-1		Accumulative roll-bonded Cu/Nb nanolaminates (ARB Cu/Nb) possess high strength, thermal stability, and radiation tolerance arising from a high content of heterophase interfaces at fine layer thicknesses. These properties can be tailored by processing parameters used in the ARB Cu/Nb fabrication process, in which layer thickness, thermal history, and strain pathway determine the interface types and resultant properties found in the material. In this work, we subject ARB Cu/Nb to annealing, and then two different rolling pathways-one where rolling direction is held constant (longitudinal rolling, or LR), and one where rolling direction is rotated by 90 degrees and held constant thereafter (cross rolling, or CR). Rolling is performed on ARB Cu/Nb over a targeted range of layer thicknesses from 193 to 25 nm and resultant bulk textures measured by neutron diffraction are correlated with mechanical properties measured by miniaturized tensile tests. The annealing procedure sharpens texture in both phases. We find that Cu mostly develops the same texture in LR and CR. In contrast, Nb develops a distinct texture along the CR pathway that is distinct from the LR texture. The composite texture of Cu/Nb is thus distinct between LR and CR pathways. This difference in texture development between Cu and Nb as a function of strain after change in rolling direction demonstrates the viability for deliberate pairing of Cu LR and Nb CR textures at a desired layer thickness. For mechanical properties, we find that differences in texture do not result in yield or flow stress differences above a layer thickness of 25 nm. Below a layer thickness of 25 nm, despite similar Taylor factors, yield and flow stress and are significantly different. This indicates texture only influences mechanical behavior at low layer thickness, where interface structure dominates mechanical properties.
10.1016-j.msea.2023.145613	6	grain; deformation; strain; strength; dislocation; cu-; tensile; size; ecap; grain size; sfe; ductility; hardening; high; stress	Layered CuCrZr/Cu composites with different densities of gradient heterogeneous interfaces were designed and prepared by powder metallurgy combined with rolling and aging. The prepared layered CuCrZr/Cu composites achieved better comprehensive properties than the homogeneous CuCrZr alloy. The evolution of local strain was analyzed by high resolution digital image correlation (DIC). A strain-transfer from CuCrZr layer to adjacent Cu layers appears at the gradient heterogeneous interface, which relieves the strain localization of CuCrZr layers in layered CuCrZr/Cu composites. The incompatible deformation between the gradient heterogeneous micro-structures across the layer interface leads to the generation and accumulation of geometrically necessary dis-locations (GNDs), which results in extra work hardening and hetero-deformation induced (HDI) strengthening. The increase in the density of gradient heterogeneous interfaces can enhance the interface constraint behavior and produce a greater HDI strengthening effect, which tends to improve the work hardening ability and HDI stress of layered CuCrZr/Cu composites. Furthermore, various crack propagation modes of crack deflection, multiple cracks and crack blunting caused by uneven stress/strain partition at the gradient heterogeneous interface of layered CuCrZr/Cu composites were characterized by in-situ tensile tests.
10.1016-j.msea.2023.145614	-1		Here, by a proper design of chemical composition to provide a guarantee of excellent conductivity and high enough strength, a new dilute Cu-Cr-Zr alloy is developed. The alloy, after two-stage heavy cold rolling and subsequent aging, consists of high-density coherent or semi-coherent nanoprecipitates and exhibits a yield strength of over 600 MPa, uniform elongation about 9.0%, and conductivity about 90% IACS.
10.1016-j.msea.2023.145637	-1		To achieve macro-segregation control and obtain a finer grain structure, oscillating laser directed energy deposition (OL-DED) was applied for the first time in the manufacturing of Cu-Fe immiscible alloys. Compared to the L-DED process, the oscillating laser did not affect the microscopic components, but it could regulate the segregation morphology. As the oscillation frequency (f) increases, the morphology of the gamma-Fe segregated phase gradually transformed from crescent to column and discrete bulk. Moreover, the oscillating laser helped to reduce the grain size of each phase in the Cu-Fe alloy. When f increased to 200 Hz, the grain size of the Cu and Fe phases reached their minimum values, measuring 4.4 mu m and 7.2 mu m, respectively, which represented reductions of 52.2% and 66.7% compared to the absence of oscillation. Furthermore, at 300 Hz, the segregation morphology transforms into discrete block-like structures with higher thermal resistivity and heat accumulation, leading to grain coarsening. Due to the grain refinement effect induced by the oscillating laser, the OL-DED fabricated Cu-Fe alloy exhibited superior tensile properties compared to the L-DED samples, achieving the highest yield strength and tensile strength at 200 Hz, measuring 345 MPa and 418 MPa, respectively. Finally, the study successfully established a correlation between the melt flow state and the macro-segregation morphology of the Fe phase based on the Reynolds model derived from the melt stirring theory, and the evolution mechanism of the grain structure was discussed based on the solidification theory.
10.1016-j.msea.2023.145715	7	irradiation; shear; grain; ta; deformation; size; radiation; voids; nanocrystalline; simulations; similar; void; temperature; irradiated; boundaries	Understanding the mechanisms behind microstructural evolution during shear deformation has been a long-standing area of interest. However, establishing a connection between microstructure, mechanical properties, and the extent of shear deformation is challenging and requires refined experimental approaches. Shear-punch testing (SPT) provides a controlled method to introduce shear into small volumes of material that later can be subjected to detailed microstructural characterization. In this study, we utilize an SPT device to induce shear deformation to pure copper (Cu) and a binary copper-chromium (Cu-Cr) alloy. Electron backscatter diffraction and transmission electron microscopy were used to study the mechanisms of plastic deformation after SPT. Our results indicate that shear deformation of pure Cu produces a dense network of intercepting microshear bands upon sustained deformation. Twin boundaries in annealed Cu undergo transformation into high-angle grain boundaries due to simultaneous deviation from the axis-angle pair condition of 60 degrees misorientation on [111] direction. The presence of 50 vol% Cr particles in the soft Cu matrix altered the shear deformation mechanism. Preferential deformation of the Cu matrix in Cu-Cr alloy led to accelerated shear-induced formation of low and high-angle grain boundaries and subsequent grain refinement. Comparatively, insignificant grain refinement occurred in pure Cu samples even at a strain similar to 10 times larger (epsilon = 4.73) than that of the Cu-Cr case (epsilon = 0.42). This study sheds light on the microstructural evolution of Cu during shear deformation and highlights the significant influence of a hard second phase in modifying the microstructural response mechanisms of a softer matrix.
10.1016-j.msea.2023.145746	15	aging; strength; conductivity; electrical conductivity; electrical; mpa; treatment; strengthening; degrees; cu-; cold; precipitation; tensile strength; tensile; iacs	Cu-0.45Cr-0.15 Mg and Cu-0.45Cr-0.15Mg-0.02Si (wt%) alloys exhibit excellent comprehensive properties after treated by multi-stage thermo-mechanical treatment, achieving the combination of high strengths and high conductivity, with hardness of 171 HV and 179 HV, electrical conductivity of 78.8 %IACS and 79.9 %IACS, tensile strengths of 555 MPa and 600 MPa and elongation of 5.6% and 6.7%, respectively. There were three forms of precipitation observed in the different stages of aging: coffee-beans, Moire ' fringes, and rod-like precipitates, and more precipitation in Cu-0.45Cr-0.15Mg-0.02Si alloy, which illustrates the addition of Si promotes the precipitation of Cr and refines precipitation, preserving high density of dislocation, achieving superior strength and conductivity. The calculation of strength and conductivity indicates that precipitation and dislocations play a significant role in the increase of yield strength and dissolved atoms are the main source of resistance.
10.1016-j.msea.2023.145802	-1		A Cu-0.48Cr-0.20Nb-0.27Zn (wt%) alloy with excellent comprehensive performance is designed and prepared by adding Zn element and combining it with a novel combined thermo-mechanical treatment. A hightemperature short-time treatment is introduced to the traditional thermo-mechanical treatment. Results show that the hardness, tensile strength, yield strength, elongation, and electrical conductivity of Cu-Cr-Nb-Zn alloy reach 180HV, 580 MPa, 535 MPa, 7.6%, and 80.2%IACS, respectively. Compared with conventional thermomechanical treatment, the alloy after the new process has increased by 15HV, 35 MPa, 40 MPa, 1.3%, and 2.0%IACS, respectively. Submicron grains and nanoscale twins emerge following high-temperature short-time treatment (850 degrees C/5min), and the grains undergo substantial refinement. Besides, this process promotes the precipitation of solid solution Cr atoms, thereby significantly improving the electrical conductivity of the alloy. Two distinct crystal structures (C14 and C15) of Cr2Nb with diameters ranging from 80 to 200 nm are observed. The alloy's strength is greatly increased in the following aging process, which precipitates a significant quantity of nanoscale Cr phase. All of the above results have certain reference significance for the optimization design of Cu-Cr-Nb alloy composition as well as performance improvement.
10.1016-j.msea.2023.145847	-1		Breaking the strength-ductility trade-off in metal materials has always been a prominent topic in materials science. Here, we proposed a novel strategy of combining rotary swaging (RS) with appropriate annealing to construct an ultrafine lamellar structure with low dislocation density in Cu-8wt% Sn alloy. This unique aniso-tropic structure achieves triple ductility without compromising strength compared with the traditional cold rolling process. Results show that the lamellar structure composed of alternating ultrafine-grained alpha-Cu and brittle Sn-rich phases can be significantly refined by RS, which can weaken stress concentration and thus reduce microcrack nucleation during tensile deformation. The lamellar ultrafine-grained alpha-Cu with low dislocation density has excellent strain hardening ability, which can effectively mediate deformation, and resist crack propagation and coalescence, thereby enhancing the ductility of materials. As a deformation method with in-dustrial application capability, RS can construct a novel lamellar structure to overcome the strength-ductility dilemma, which deserves attention in materials science.
10.1016-j.msea.2023.145905	-1		Tailoring the size, shape and distribution of nano-particles (NPs) is vital for improving the properties of oxide dispersion strengthened Cu (ODS-Cu). In this study, we used Ti doped Cu-Al powders as starting materials and employed internal oxidation to introduce dense NPs into Cu matrix. Multi-scale oxides are detected in the internally oxidized and hot pressed specimen. It was found that the formation of coarse particles is unavoidable, and they were formed during gas atomization and internal oxidation (along grain boundaries). Ti doping can effectively suppress the growth of the NPs, thus resulting in a particle number density with an order of 1023 m- 3. The mechanical and electrical properties of the Ti doped specimen were tested and a comparison is made with Glidcop-25. The yield strength and microhardness of Ti doped ODS-Cu are 54.6 MPa (from 331 MPa to 385.6 MPa) and 33.5 HV0.1 (from 118 HV0.1 to 151.5 HV0.1) higher than that of Glidcop-25, while the conductivity and uniform elongation were reduced by 2.3 % IACS (from 87%IACS to 84.7%IACS) and 1.9 % (from 13.2 % to 11.3 %), respectively. Numerous NPs play a major role in enhancing strength, with modulus hardening (contribution to enhancement reached 66 %) being recognized as the primary mechanism for this enhancement.
10.1016-j.msea.2023.145928	-1		The matching of mechanical properties between Cu-15Sn-0.3Ti alloy and Nb was the key to the formation of Nb3Sn superconducting wires. However, the Cu-15Sn-0.3Ti alloy treated with homogenized annealed (HA) still could not meet the requirements for synergistic deformation with Nb. In this work, a novel mechanical-heatelectricity synergistic method was proposed, which successfully formed equiaxed crystal microstructures with annealing twins (ATs) to enhance the strength of Cu-15Sn-0.3Ti alloy without loss of elongation. The experimental results indicated that the combination method of Rotary swaging (RS) and Electric pulse treatment (EPT) could induce recrystallization of deformed microstructure to refine the average grain size of the HA state sample from >= 500 mu m to 9.3 mu m, and the UTS and YS were increased by 34 % and 28 %, respectively. It is worth noting that this process was completed in only 90 s. The relationship between the changes in mechanical properties of Cu-15Sn-0.3Ti alloy and microstructure evolution during the EPT process was elucidated. The role of stacking faults (SFs) in the formation of ATs and recrystallization was revealed. The recrystallization efficiency of EPT and annealing treatment was compared by calculation.
10.1016-j.msea.2023.145932	15	aging; strength; conductivity; electrical conductivity; electrical; mpa; treatment; strengthening; degrees; cu-; cold; precipitation; tensile strength; tensile; iacs	The homogenization heat treatment is a key procedure to controlling the second phase, enhancing composition uniformity and workability of as-cast Cu-15Ni-8Sn alloy. Nonetheless, high annealing temperature and long holding time result in high energy consumption, high costs and severe oxidation. The effects of electropulsing treatment (EPT) and conventional homogenization treatment (CHT) on the microstructure and mechanical properties of Cu-15Ni-8Sn alloy by downward continuous casting were studied. The results showed that with increase of pulse current density, the treatment temperature of the alloy increased continuously. Subsequently, gamma-(Cu, Ni)3Sn phase and lamellar (alpha+gamma) phase underwent progressive spheroidizaiton and dissolution. Compared with CHT, EPT contributes to significant reductions in both treatment temperature (about 100 degrees C) and treatment time (1/34 of the CHT), the tensile strength decreased from 437 MPa (as-cast alloy) to 380 MPa, while the elongation increased dramatically from 9.2 % to 41.6 %. Compared with being treated by CHT, the alloy treated by EPT performed excellent comprehensive mechanical properties. The extra free energy provided by EPT di-minishes the thermodynamic energy barrier of gamma phase dissolution and significantly accelerates atomic diffusion, which mainly contribute to rapid homogenization of Cu-15Ni-8Sn alloy by EPT at lower temperature. EPT can work as a novel homogenization heat treatment process for metallic materials, boasting advantages such as high efficiency, low energy consumption and low costs.
10.1016-j.msea.2023.145955	-1		In this paper, using the ultrafine W-27.5 wt%Cu-2wt%Mo-1.75 wt%Ni-0.75 wt%Fe-(0-1)wt%CeO2 alloy powders as raw materials, W-Cu-Mo-Ni-Fe-CeO2 alloys with excellent performances were prepared by low temperature sintering. Two-step reduction method consisting of carbothermic pre-reduction and hydrogen deep deoxidation was used to produce ultrafine W-Cu-Mo-Ni-Fe-CeO2 alloy powders with uniform distributed composition. All sintered blocks obtained relatively high densification degree (97.1 %similar to 99.2 %) to ensure the excellent comprehensive properties. Moreover, the existences of gamma-(Cu, Ni, Fe) and W-Mo solid solutions ensured the alloy possessed a high mechanical strength . More importantly, the introduction of CeO2 inhibited the growth of W-Mo grains. With increasing CeO2 content from 0 wt% to 1 wt%, the W-Mo grain size decreased from 1.76 mu m to 1.44 mu m. Especially, alloy sample with the highest tensile and compressive strengths was obtained by adding 0.5 wt% CeO2, which were 602 MPa and 3187 MPa, respectively. Furthermore, owing to finer W-Mo grain size, this sample also possessed the maximum micro-hardness and bending strength of 482 H V and 1685 MPa, respectively. Nevertheless, the existences of Ni, Fe and CeO2 also destroyed the electrical conductivities of the samples to some extent. Specifically, with increasing CeO2 content from 0 wt% to 1 wt%, the electrical conductivity of the sample decreases from 32.56 %IACS to 30.16 %IACS.
10.1016-j.msea.2023.145972	-1		In the present study, the effect that superplastic deformation exerts on the microstructures, texture, and me-chanical properties in 2A97 Al-Cu-Li alloy was investigated. The as-received material was deformed to a series of strains for 50%, 100%, 150%, and 200% at 430 degrees C with an initial strain rate of 2 x 10-3 s- 1, and the grain structure, dislocation, secondary phase particles, cavities, texture, and tensile properties of deformed alloys were demonstrated and discussed comprehensively. Results show that with the increase of superplastic strain, the grain size of the alloy decreased gradually due to the dynamic recrystallization, and the Cu-rich secondary phase particles partially dissolved and partially coarsened. The initiation and growth of the cavities mainly depended on the grain boundary sliding and grain rotation, the fraction of cavities increased rapidly at higher strains (100%-200%). Superplastic deformation weakened the rolling texture (Brass, Copper, and S) and enhanced the recrystallization texture (Goss and ND-Rotated-Cube). The strength of the material decreased with increasing the superplastic strain firstly, after the strain exceeded 100%, the strength started to increase. The fracture elon-gation varied oppositely. The strengthening mechanism was discussed in detail. The coarsening of Cu-rich sec-ondary phase particles and the rapid formation of cavities resulted in the drastic loss in ductility after the strain of 100%.
10.1016-j.msea.2023.145990	-1		We utilized a Cu-Ni co-electrodeposition method to enhance the mechanical strength of nanotwinned copper (NT-Cu), achieving an ultimate tensile strength (UTS) of over 866 +/- 20.1 MPa, a 13.1% increase from the original NT-Cu (UTS max of 766 +/- 2.7 MPa). ICP-MS analysis showed a nickel content of 0.467 ppm. The Cu-Ni alloy also demonstrated an international annealed copper standard (IACS) value of over 81%, outperforming cold-rolled Cu foils in terms of mechanical strength and IACS value. The addition of Ni was to reduce the Cu grain size, and to increase the twin density of the NT-Cu. A modified confined layer slip (CLS) model is proposed to account for the refined microstructure of the NT-Cu-Ni alloys. Therefore, this approach can tailor the microstructure of NT-Cu, increase its strength, and maintain high electrical conductivity, making it a promising option for advanced packaging materials.
10.1016-j.msea.2023.146068	15	aging; strength; conductivity; electrical conductivity; electrical; mpa; treatment; strengthening; degrees; cu-; cold; precipitation; tensile strength; tensile; iacs	High-strength Cu-Ti-Fe alloys were prepared and investigated in this study. The alloy was subjected to cold deformation and aging treatment, and revealed the transformation mechanism of the microstructure and properties. Cold deformation of 60 %, aging at 450 C for 240 min, can optimize the hardness and conductivity of the Cu-Ti-Fe alloy. The hardness and electrical conductivity of Cu-1.5Ti-0.3Fe alloy increased from 196.8 HV to 7.8 % IACS to 269.3 HV and 19.8 % IACS after aged. Cu4Ti and Fe2Ti are the mainly precipitated phases in Cu-Ti-Fe alloy, which effectively obstructs dislocations slipping and delays recrystallization, and the most important strengthening mechanism. The concentration of solute atoms increased could further improve the grain boundary strengthening, solution strengthening, and deformation strengthening.
10.1016-j.msea.2024.146098	-1		Copper alloys with high strength and electrical conductivity are a key focus for next-generation electronic materials. In this study, a precipitation-strengthened Cu-0.96Ni-0.22 P alloy with tensile strength, yield strength, and electrical conductivity values of 630 MPa, 614 MPa, and 64 %IACS, respectively, were designed via thermomechanical treatment. The nanoprecipitates remain in the form of the G.P zone during 450 degrees C aging from 30 to 120 min. Theoretical calculation results showed that the precipitation of coherent G.P zones contributes to a major strengthening to the Cu-Ni-P alloy. Coarsening of precipitates and recrystallization were the primary reasons for softening during the over-aged stage. The uniform growth of Ni2P phases was the main precipitation process during stable transformation, and the simultaneous precipitation of the Ni12P5 phase and a cube-like Ni3P phase was observed with a higher coarsening rate.
10.1016-j.msea.2024.146110	-1		The effects of Mn content on the Sn distributions, grain sizes, second phases, and mechanical properties of Cu-9Ni-6Sn-XMn alloys (wt%, X = 0, 0.1, 0.5, and 1.0) were studied in this paper. The mechanisms of acting and strengthening through which Mn could promote grain refinement in the alloy were discussed. The results showed that the addition of Mn transforms the as-cast microstructure of the alloy into equiaxed grains, and the grains are obviously refined. When the amount of Mn is approximately 0.1 wt%, the average grain size of this alloy is 91.75 mu m, and the grain refinement effect is greatest in the experimental range. In addition, Mn increases the uniformity of the distribution of Sn in the as-cast microstructure. Differential scanning calorimetry (DSC) analysis revealed that the addition of Mn increases the undercooling of the as-cast Cu-9Ni-6Sn alloy and decreases in the critical nucleation radii of the grains. Further microstructure observation showed that Mn is dissolved mainly in the gamma-(Cu,Ni)3Sn phase. Consequently, the interfacial relationship between the gamma-(Cu,Ni)3Sn phase and the matrix transforms from incoherent to semicoherent. Compared with those of the Cu-9Ni-6Sn alloy, the strength and elongation of the alloy with added Mn are relatively great. When the content of Mn is 0.1 wt%, the strength of the alloy increases from 359.75 MPa to 423.54 MPa, while the elongation remains at 19.14 %. The synergistic effect of solution strengthening and fine grain strengthening of Mn is the main reason for the great improvement in the mechanical properties of the alloy.
10.1016-j.msea.2024.146186	14	strength; properties; conductivity; electrical; mechanical; cu-; grain; mpa; electrical conductivity; aging; precipitation; phase; mechanical properties; tensile; phases	This investigation systematically explores the impact of minor Cr additions on the microstructural evolution, precipitation kinetics, mechanical properties, and electrical properties of Cu-Ag alloys, with a specific focus on Cu-6 %Ag-(0.4 %Cr). The alloys underwent casting through a vacuum induction furnace, followed by meticulous treatments involving solution heat and aging at varied temperatures and durations. Results indicate a significant improvement in the mechanical properties of Cu-Ag alloy upon Cr addition, with only a slight reduction in electrical conductivity. As per differential scanning calorimetry (DSC) measurements, the activation energy for continuous precipitation in the Cu-Ag-Cr ternary alloy is slightly higher than that in Cu-Ag. However, Cu-Ag-Cr lacks peaks corresponding to the discontinuous phase. Microstructural analysis unveils that Cr incorporation suppresses the discontinuous precipitation of Ag, fostering continuous precipitation during aging. Moreover, both micro-sized and nano-sized Cr particles were detected in the Cu-Ag-Cr alloy, contributing to the formation of finely spaced continuous Ag precipitates and fine Cr precipitates. This intricate microstructure imparts higher hardness and strength to the alloy compared to Cu-Ag. Specifically, following aging treatment at 450 degrees C for 2 h, the Cu-6 %Ag-0.4 %Cr alloy exhibited a remarkable increase of 76.1 % in hardness, 43.6 % in strength, and a moderate decrease of 15.8 % in conductivity.
10.1016-j.msea.2024.146219	-1		Cu-Ag alloy fibers are known for their excellent electrical and thermal conductivity, and are widely used in various fields, such as electronics, transportation, and processing due to their low price and simple preparation process. Nevertheless, this trade-off relation between strength and electrical conductivity of Cu-Ag alloys restricts their scope of application. In order to prepare Cu-Ag alloy fibers with high strength and high electrical conductivity, three different processes: cold drawing, surface electrodeposition and electrolytic polishing, are investigated and comprehensively utilized. By comparing the evolution of microstructure and properties in Cu-Ag alloy fibers, along with the corresponding mechanisms for strengthening and conductivity, one most suitable process path is explored. Cold-drawing is utilized to reduce the grain size, which, in turn, enhances the strength of the fibers. Meanwhile, it refines the internal grains of the alloy by shearing and deflecting each other, ultimately resulting in a fiber texture along the drawing direction. The main contributors to the strength of Cu-Ag alloy fibers are dislocation strengthening, grain boundary strengthening, and texture strengthening. The slight difference is that for electrical conductivity, dislocation and grain boundary play a crucial role. Electrodeposition of copper on the fiber surface is an effective method for improving the electrical conductivity of the fiber, which is achieved by creating a dense conductive pathway on the surface of the fiber. However, this process leads to a reduction in strength . Therefore, electrolytic polishing is subsequently used to regulate the plating thickness in order to obtain Cu-Ag alloy fiber with synchronous increase of strength and electrical conductivity.
10.1016-j.msea.2024.146230	-1		In this study, a novel Cu-0.3Sn-0.2Zr (wt%) alloy was designed to investigate the influence of Zr addition on the microstructure and properties of the Cu-0.3Sn alloys. We have discovered that the addition of Zr could not only greatly refine the grain structures of the Cu-0.3Sn alloy and contribute to forming a large number of nanoscale Zr-rich particles, but also leads to the formation of core-shell structure with a large amount of Sn atoms segregated at the surface of the microscale and nanoscale Zr-rich particles. As a result, all of the tensile strength, electrical conductivity and softening temperature of the Cu-0.3Sn-0.2Zr alloy were improved when compared with the Cu-0.3Sn alloy. After cold drawing at an accumulated strain of 6.8 combined with a two-step aging treatment, a good combination of an ultimate tensile strength of similar to 724 MPa, an electrical conductivity of similar to 76.8% IACS and a softening temperature of similar to 425 degrees C were achieved in the Cu-0.3Sn-0.2Zr alloy, which was similar to 147 MPa, similar to 0.7 % IACS and similar to 90 degrees C higher than that of the Cu-0.3Sn alloy after cold drawing at the same accumulated strain of 6.8, respectively. Our research elucidates that the Cu-Sn-Zr alloys represent a category of potential copper alloys with high strength, high conductivity and excellent softening resistance performance.
10.1016-j.msea.2024.146419	14	strength; properties; conductivity; electrical; mechanical; cu-; grain; mpa; electrical conductivity; aging; precipitation; phase; mechanical properties; tensile; phases	In this paper, a novel Cu-0.60Cr-0.20Nb-0.05Si-0.02Ca-0.02Ce (CCNSCC, wt%) alloy is designed. By comparing the differences in the properties and microstructure with the Cu-0.60Cr-0.20Nb (CCN, wt%) alloy under the same process, the effects of trace Si, Ca, and Ce elements on the CCNSCC alloy are disclosed. After undergoing cold rolling by 80% and aging at 450 degrees C for 60 min, the CCNSCC alloy exhibits a tensile strength of 524 MPa and a softening temperature of 600 degrees C. These values represent an increase of 104 MPa and 90 degrees C respectively compared with the CCN alloy. After a multi-stage combined thermo-mechanical treatment including preaging at 400 degrees C for 30 min, the tensile strength and electrical conductivity of the CCNSCC alloy reach 618 MPa and 75.2% IACS respectively. Microstructure analysis shows the existence of rod-like and polygonal Cr8Nb3Si 8 Nb 3 Si particles, as well as globular, ellipsoidal, and crescent-shaped (Ca,Ce)Cu5 5 particles. During the process of aging, the precipitation of the Cr phase occurs at the phase boundaries of Cr8Nb3Si 8 Nb 3 Si particles. Additionally, significant quantities of fine Cr particles at the nanoscale surround the Cr8Nb3Si 8 Nb 3 Si particles, exerting a beneficial influence on the strength and electrical conductivity of the CCNSCC alloy. Besides, the CCNSCC alloy has finer Cr particle size and lower volume fraction of recrystallized grains after aging in comparison to the CCN alloy. This indicates that the addition of trace Si, Ca, and Ce elements significantly inhibits the growth of Cr particles and occurrence of recrystallization. Plenty of dislocations are observed in different states of the CCNSCC alloy, and their interaction with the Cr precipitates is the primary factor contributing to the excellent mechanical properties of the CCNSCC alloy. The findings of this study provide valuable insights for improving the properties and microstructure of Cu-Cr-Nb alloys.
10.1016-j.msea.2024.146434	-1		The Cu-15Ni-8Sn-xHf (wt%, x = 0-0.6) alloys were prepared by vacuum melting, and the effect of Hf on the micro -structure of as -cast, as -solution -treated and as -aged alloys was systematically investigated, as well as the alloy aging stability. The Hf addition provided a significant role on refining the solidification structure and reducing the micro -segregation degree, and it also made gamma- D0 3 phases more likely to form in needlelike-shape rather than lamellar -shape. With the presence of more Hf atoms, their existence form was accordingly changed from solid solute atoms to nano -scale precipitation phases and then to micron -scale segregation phase. A small content of Hf (0.1 wt%) could effectively improve the aging stability by inhibiting the growth of gamma- D0 3 . Once its content reached or exceeded 0.3 wt%, the harmful discontinuous precipitation was completely inhibited, and the common lamellar -shape gamma- D0 3 locating around the grain boundary was no longer formed. Even the alloy failed at higher temperatures, it could only be carried out through the continuous precipitation method, namely the generation of needlelike-shape gamma- D0 3 uniformly in the matrix. The appropriate Hf addition was capable of extending the alloy aging window, and the hardness of Cu-15Ni-8Sn-0.3Hf alloy could still exceed 360 HV even after 48 h aging.
10.1016-j.msea.2024.146463	-1		The plastic deformability of ODS copper (Al 2 O 3 /Cu composite) always limits its widespread commercial application. In this work, the thermodynamically metastable mono -phase CuCr alloy was used to fabricate 2.5 vol% Al 2 O 3 /Cu-0.3 vol%Cr by an internal oxidation method with a subsequent solution treatment to improve the plastic deformation ability. The influence of dissolved Cr on the hot deformation property and dynamic recrystallization (DRX) behavior of Al 2 O 3 /Cu composite was studied, and the softening mechanism of Al 2 O 3 / Cu-Cr composite was revealed. The results show that the solid solution of Cr at high temperature can significantly improve the hot deformability of Al 2 O 3 /Cu composite. The maximum reduction of peak stress of 2.5 vol% Al 2 O 3 /Cu-0.3 vol%Cr composite is 57 % lower than that of 2.8 vol% Al 2 O 3 /Cu composite. Furthermore, the DRX critical values of 2.5 vol%Al 2 O 3 /Cu-0.3 vol%Cr composite is lower than that of 2.8 vol% Al 2 O 3 /Cu composite, and the DRX occurs earlier in Al 2 O 3 /Cu-Cr composite. The strain -compensated constructive model of Al 2 O 3 / Cu-Cr composite was established with a relation coefficient (R 2 ) of 0.92, which proves the accuracy of the model. Finally, the hot processing map of Al 2 O 3 /Cu-Cr composite was constructed based on a dynamic analysis model, and the appropriate hot processing parameter of Al 2 O 3 /Cu-Cr composite was obtained with temperature of 1205 K-1223 K and strain rate of 0.022 s -1 -0.97 s -1 . The results are beneficial to improve hot deformation property of Al 2 O 3 /Cu-Cr composite and large sized bulks fabrication.
10.1016-j.msea.2024.146479	-1		Cu-0.4Cr-0.2Zr-0.2Hf (wt%) alloy plates were prepared by cryogenic rolling and intermediate aging process. The effects of intermediate aging and cryogenic rolling on the microstructural, mechanical and textural evolutions were studied by X-ray diffraction, electron backscatter diffraction and transmission electron microscopy. The results show that the combination of cryogenic rolling and intermediate aging resulted in the formation of highdensity dislocations, nanoscale deformation twins, deformation bands, and nano -precipitates in the Cu-Cr-Zr-Hf alloys. The nano -precipitates formed during the intermediate aging effectively increase the flow stress, and promote the formation of the nano -twins. Besides, the combination process can both reduce the fraction of the remnant grains and refine the width of remnant grains, promoting the homogeneous deformation of the Cu-Cr-Zr-Hf alloys. The reduction of the remnant grains decreases the Brass component, and increases the S component. The profuse nano -twins and Brass -type shear band contribute to the increase in the Y component.
10.1016-j.msea.2024.146497	-1		The evolution of the microstructure, physical and mechanical properties of pre-deformed samples of the nonstoichiometric alloy Cu-56at%Au in the process of the L1o-type atomic ordering was studied. The duration of annealing at 250 degrees C ranged from 1 h to 2 months. Changes in microhardness and electrical resistivity at various stages of the disorder -> order transition were found out, the microstructure was examined using a transmission electron microscope, XRD-scans and tensile tests were performed. Based on the resistometric results and XRDanalysis, the dependence of the fraction of the ordered phase vs. the annealing time was plotted. Consecutive changes in structural states observed during long-term annealing were considered through the competition between the energy of the elastic stresses, the surface energy and the energy of the dislocation structure. An abnormal increase in the strength properties of the alloy during annealing was found: the yield strength and microhardness of the initially deformed samples significantly increase (at 15 % and 30 %, respectively), at the same time there is a drop in electrical resistivity and an increase in plasticity. An attempt was made to describe the observed phenomena considering mutual effect of ordering and recrystallization. Discovered annealing hardening was explained in terms of the suppression of recrystallization by ordering, which is confirmed by the preservation of a high density of inherited dislocations in an ordered matrix and low plasticity of the annealed samples. The retardation in the recrystallization rate with an increase in the preliminary deformation strain of the alloy was discovered.
10.1016-j.msea.2024.146510	14	strength; properties; conductivity; electrical; mechanical; cu-; grain; mpa; electrical conductivity; aging; precipitation; phase; mechanical properties; tensile; phases	The microstructural evolution of Cu-3Ti-2Ni alloy under primary and secondary cold rolling combined aging was investigated through various characterization techniques including transmission electron microscopy (TEM), scanning electron microscope (SEM), and X-ray diffraction (XRD). Additionally, the electrical and mechanical properties during different stages of aging were examined to reveal the organizational changes and performance variations of Cu-3Ti-2Ni alloy under primary and secondary aging. This study revealed that the alloy exhibited optimal primary aging performance at 450 degrees C for 4 h, with a strength of 954 MPa and an electrical conductivity of 21.5 %IACS (International Annealed Copper Standard for Conductivity). In comparison to primary aging, both strength and electrical conductivity were effectively improved under secondary aging conditions. The optimum secondary aging process was determined to be aging at 400 degrees C for 3 h, resulting in a strength of 1133 MPa and an electrical conductivity of 24.2 %IACS. During the aging process, the matrix witnessed the formation of numerous elliptical disc-shaped NiTi and Ni3Ti phases. Notably, the interface of NiTi phases exhibited a stronger coherency effect compared to Ni3Ti. beta '-Cu4Ti precipitated uniformly within the matrix during aging, enhancing the alloy's strength . A recovery and recrystallization process occurred during aging, leading to the formation of sub-grains within the matrix.
10.1016-j.msea.2024.146524	-1		Gradient nanostructured (GNS) metallic materials have shown significant potential in achieving excellent mechanical properties. However, the underlying strengthening mechanisms resulting from plastically inhomogeneous deformation in GNS materials, particularly those involving nanotwinned structures, remain inadequately understood. In this study, a gradient nanograined-nanotwinned (GNNT) surface layer was generated on a Cu -Al alloy using the severe plastic deformation technique known as single -point diamond turning. Uniaxial tensile and localized micropillar compression tests were conducted to compare the mechanical properties of GNNT samples with conventional gradient nanograined (GNG) and uniform coarse -grained (CG) Cu/Cu-Al counterparts. The results revealed that the GNNT samples exhibit excellent strength -ductility synergy, with a yield strength of approximately 329 MPa, tensile strength of around 477 MPa, and uniform ductility of about 48 %, thereby demonstrating remarkable strain hardening capacity and mechanical stability. These characteristics are further supported by the observed strong back stress effect, well-preserved mobile dislocation density, and effective suppression of grain coarsening in the GNNT surface layer. In contrast to the evident mechanically induced grain coarsening through grain boundary (GB) migration in the GNG surface layer, grain coarsening through twin boundary (TB) migration in GNNT surface layers is effectively inhibited by Lomer-Cottrell (L -C) locks formed by TB -stacking fault and TB -TB intersections, resulting in significantly enhanced structural stability. Furthermore, the L -C locks also extensively contribute to the high density of mobile dislocations observed in the GNNT samples. These findings provide valuable insights into the optimization of GNS structures for achieving excellent strength -ductility synergy in metallic materials.
10.1016-j.msea.2024.146526	-1		The microstructural evolution, precipitation behavior and mechanical properties of Cu-19Ni-6Cr-xMn (x=0, 1, 3, 5, 7, 9 wt%) alloys were examined in the presence of solution treatment, cold rolled treatment and aged treatment. The results show that aged Cu-19Ni-6Cr-7Mn alloy exhibits superior mechanical properties with a hardness of 379 HV, tensile strength of 1012 MPa, and elastic modulus of 149.5 GPa, which is the maximum reported value for elastic modulus of copper alloys. The Mn element promotes the uniform distribution of the precipitates and grain refinement. Thermodynamic calculations indicate that the formation of the NiMn precipitates takes precedence over the NiCr-rich precipitates in this alloy. Three typical precipitates were detected in the Cu-19Ni-6Cr-7Mn alloy, including submicron-sized Cr-rich precipitates (>500 nm), nano-sized bcc-Cr precipitates (30-70 nm), and nano-sized NiMn precipitates with γ′ ordered structure (3-5 nm). Precipitation plays a major role in improving the strength of the alloy. The synergistic effect between multi-scale precipitates, high-density dislocations, and solution strengthening has achieved significant breakthroughs in mechanical properties which open up new possibilities for engineering applications requiring high-strength and highelasticity copper alloys.
10.1016-j.msea.2024.146716	-1		Aging is an important step in improving the comprehensive properties of Cu-3.5Ti alloy. However, both prolonged holding times and high heat treatment temperatures lead to significant oxidation and substantial energy consumption. The effects of heat treatment (HT) and electropulsing treatment (EPT) on the microstructure and mechanical properties of the solid solution Cu-3.5Ti alloy were comparatively examined in this study. The findings demonstrated that EPT quickly completed the processes of spinodal decomposition and short-range ordered to long-range ordered phase transformation, thereby fully precipitating fine and diffusive beta '-Cu4Ti phase, which greatly enhanced the precipitation strengthening effects. In addition to enhancing the strength of the alloy, EPT significantly reduced the peak aging time (to just 1/12 of that of HT) and greatly increased the plasticity (elongation to failure rose by 47 % compared to HT). The main reason for the rapid completion of the spinodal decomposition and the full precipitation process by the EPT was the additional free energy provided by the electropulsing, which significantly accelerated the Ti atomic diffusion and lowered the nucleation barrier of the beta '-Cu4Ti phase. EPT is a toughening heat treatment process for metallic materials, which offers the advantages of high efficiency, low energy consumption, and low cost.
10.1016-j.msea.2024.146718	14	strength; properties; conductivity; electrical; mechanical; cu-; grain; mpa; electrical conductivity; aging; precipitation; phase; mechanical properties; tensile; phases	To form the Ni3Al precipitate, current researches on Cu-Ni-Al alloys mainly focus on a Ni/Al atomic ratio of 3.0. However, incorporating the effects of solid solutions and aging processes suggests that the optimal Ni/Al atomic ratio for Cu-Ni-Al alloys deviates from the stoichiometry of Ni3Al by 3.0. This study investigated how varying Ni/Al atomic ratios impact the microstructure and properties of Cu-Ni-Al alloys. Upon aging at 500 degrees C for 24 h, the alloy revealed two types of Ni3Al precipitates and a composition change with reduced Ni and increased Al as the Ni/Al ratio decreased from 3.0 to 1.5, subsequently enhancing its electrical conductivity. A reasonable Ni/Al atomic ratio of 2.0 was identified instead of 3.0, and at 2.0 ratio the Cu-13.3Ni-6.7Al alloy exhibited an ultimate tensile strength of 1008 MPa and an electrical conductivity of 16.0 %IACS. Compared to alloys with a Ni/Al ratio of 3.0, this composition showed a 3.5 % increase in ultimate tensile strength and a 14.4 % enhancement in electrical conductivity. These improvements are attributed to the enhanced destabilization of the FCC phase at lower Ni/Al ratios due to solid solution effects, leading to a higher nucleation drive and the formation of uniformly distributed precipitates within the alloy. These insights offer valuable directions for developing environmentally benign Cu alloys with ultra -high strength and electrical conductivity.
10.1016-j.msea.2024.146763	-1		In traditional dispersion-strengthened (DS) copper alloys, inert nanoparticles selected as strengthening phase were noncoherent or semi-coherent with the matrix. In this work, high-density YbAlO3 ceramic nanoparticles (NPs) with an average size of similar to 6 nm were introduced into copper matrix by mechanical alloying and spark plasma sintering. Microstructural characterizations confirm that YbAlO3 NPs with different size are all fully coherent with the matrix and have a superlattice structure, and the coherency strain remains constant with the size increasing of the NPs. The extremely low lattice mismatch between the NPs and Cu prevents the NPs from coarsening even annealing at 900 degrees C (0.87 T-m), which leads to remarkable improvement in strength and thermal stability of the alloy at high temperatures. The tensile strength of the alloy reaches up to 585 MPa at 300 degrees C and 449 MPa at 450 degrees C, over two times higher than other DS copper alloys. Moreover, no grain growth and dislocation density reduction occurs after annealing at 900 degrees C for 3 h, demonstrating an excellent thermal stability of the alloy. This work proves the significant advantages of fully coherent NPs for DS materials and provides a new pathway for designing materials intended to serve at high temperatures.
10.1016-j.msea.2024.146854	-1		The microstructural evolution and recrystallization behavior of a single-phase Cu-18Ni-17Zn alloy during annealing has been investigated. The strengthening effects of the solute atom concentration, grain size, and recrystallized volume fraction have also been studied. The results have shown that the difference in yield strengths for the fully recrystallized samples mainly depended on the grain boundary strengthening effect. This is attributed to a constant (similar to 41 MPa) solid-solution strengthening contribution in the completely recrystallized Cu-18Ni-17Zn alloy. When compared with pure copper, this alloy exhibited a high Hall-Petch constant (similar to 0.36 MPa m(1/2)), which is due to the higher grain boundary interface energy. A discontinuous recrystallization occurred in the alloy in the temperature range 400 degrees C-500 degrees C. Furthermore, the yield strength was linearly correlated to the recrystallized volume fraction in the partial recrystallized samples. Moreover, the addition of Ni and Zn increased the recrystallization temperature and slowed the recrystallization kinetics. The activation energy for the recrystallization was estimated as 92.6 +/- 5.1 kJ/mol in the cold-rolled Cu-Ni-Zn alloy, which indicates that the grain boundary migration during recrystallization was mainly controlled by diffusion along the grain boundaries. In addition, the recrystallized grains preferentially nucleated at shear bands with high strain energies in the Cu-Ni-Zn alloy during annealing. As the regions of shear banding were completely consumed, new recrystallized nuclei formed at the grain corners. The limited number of nucleation sites resulted in a low Avrami exponent value that ranged from 0.41 to 0.61.
10.1016-j.msea.2024.146946	15	aging; strength; conductivity; electrical conductivity; electrical; mpa; treatment; strengthening; degrees; cu-; cold; precipitation; tensile strength; tensile; iacs	In this paper, the effect of the second-stage rolling deformation of Cu-Ni-Si alloy on its stress relaxation resistance was studied, and the mechanism of the change in microstructure and properties before and after stress relaxation was explored. The results show that the tensile strength and yield strength of Two-stage rolling peak aging (TRPA) 43.7 %, TRPA68.8 %, TRPA80.3 % and TRPA96.1 % alloys at 150 degrees C are close. After stress relaxation, the stress relaxation rates of these alloys are 7.7 %, 11.24 %, 14.69 % and 19.4 %, respectively. It is found that the smaller the second-stage rolling deformation, the better the stress relaxation resistance of the alloy, especially the stress relaxation resistance of the TRPA43.7 % alloy, which is 60.31 % higher than that of the TRPA96.1 % alloy. According to EBSD analysis, it was found that the increase in the number of twins can improve the stress relaxation resistance of the alloy. However, the occurrence of recrystallization reduces the stress relaxation resistance. Additionally, it was determined that the precipitated phase is the delta- Ni 2 Si phase with an orthogonal structure. Before stress relaxation, the size of the precipitated phase of the alloy with TRPA96.1 % is larger than that of the alloy with TRPA43.7 %, and after stress relaxation, the precipitated phase further grows. The influence of the interface relationship between delta- Ni 2 Si phase and Cu matrix on the stress relaxation properties of TRPA43.7 % and TRPA96.1 % alloys before and after stress relaxation was investigated using the mismatch theory. In summary, this study reveals that the size of delta- Ni 2 Si phase, dislocation density and recrystallization are the key factors affecting the stress relaxation resistance of Cu-Ni-Si alloy.
10.1016-j.msea.2024.146950	14	strength; properties; conductivity; electrical; mechanical; cu-; grain; mpa; electrical conductivity; aging; precipitation; phase; mechanical properties; tensile; phases	A Cu-9Ni-6Sn alloy bar with pronounced axial columnar grains and a diameter of 10.5 mm was fabricated by using directional solidification technology, which was directly cold-drawn into a superfine alloy wire with a diameter of 40 mu m without intermediate annealing. The strength and microstructure evolutions of the Cu-9Ni-6Sn alloy during the cold drawing were studied. The results indicate that twinning is more likely to occur in fiber structures ranging from 60 to 120 nm. A dual-fiber structure consisting of <111> and <100> orientations formed after cold-drawing. Unexpectedly, a large number of deformation twins were discovered within the <111> fibrous texture and later transformed into detwinning structures, disrupting the axial fibrous texture. The generation of deformation twinning primarily results from Ni and Sn elements disrupting crystal symmetry and reducing stacking fault energy of the alloy and the formation of <111> texture. The combined effects of detwinning structures and dislocation wall induced work-softening of the alloy, enabling high-strain processing and ultimately yielding nanocrystalline grains, i.e., the Cu-9Ni-6Sn alloy underwent cold drawing with a high train of 11.23 and obtained an average grain size of similar to 38 nm, which exhibited a tensile strength of 1453 MPa.
10.1016-j.msea.2024.146952	-1		In this study, the microstructure and properties evolution of Cu-2.7Ti-0.2Fe alloy (wt%) during cold drawing and subsequent aging treatment were investigated. The grain refinement mechanisms of the samples were analyzed in detail and systematically based on EBSD characterization. Dislocation evolution realized the refinement of grains by promoting the transformation of dislocation walls/cell walls to high angle grain boundaries. The twin-twin/dislocation intersections were another important way of refinement. Strong <100> and <111> fiber textures were formed during drawing, which had the volume fractions of 24.9 % and 55.5 %, respectively, in the sample with true strain of 8.4. The <100> fiber texture was mainly associated with the twinning and dislocation slipping in the high Schmid factor condition, while the decrease in the fraction of <100> fiber texture was mainly attributed to the grain refinement. The wire peak-aged at 380 degrees C for 2 h achieved excellent comprehensive properties with yield strength of 1596 MPa, tensile strength of 1682 MPa and electrical conductivity of 15.5 %IACS.
10.1016-j.msea.2024.146990	15	aging; strength; conductivity; electrical conductivity; electrical; mpa; treatment; strengthening; degrees; cu-; cold; precipitation; tensile strength; tensile; iacs	The effects on microstructure and properties of Cu-Cr-Sn-Zn with combined addition of Zr and Mg elements and their evolutions in the process of solid solution and thermomechanical treatment for etching high pin lead frames were studied. The microstructure was analyzed by OM, SEM, TEM, and EBSD. The results show that Cu-Cr-Sn-Zn and Cu-Cr-Sn-Zn-Zr-Mg alloys have the best performance after primary aging at 440 degrees C for 4 h and secondary aging at 400 degrees C for 4 h . The hardness and conductivity of the two alloys are 154 HV&78.3%IACS and 171 HV&77.8%IACS, respectively. Cu-Cr-Sn-Zn-Zr-Mg alloy final products shown better comprehensive performance, with conductivity, tensile strength, and hardness of 81.4%IACS, 580 MPa, and 175 HV respectively. The addition of Zr and Mg elements slows down the precipitation process of Cu-Cr-Sn-Zn alloy, refines the Cr phases, and inhibits the coarsening of Cr phases. Nano Cr clusters and coherent fcc Cr phases were observed during the aging process at 440 degrees C for 4 h and 400 degrees C for 4 h, which is difficult to observe in Cu-Cr-Sn-Zn alloy due to the precipitation and coarsening of Cr phases in a rapidly way. The surface roughness of Cu-Cr-Sn-Zn-Zr-Mg alloy without coarsened Cr phases is lower with Sa = 0.2681 mu m.
10.1016-j.msea.2024.146997	-1		The dynamic mechanical properties and behaviors of an oxide dispersion strengthened copper alloy (ODS Cu) are investigated herein within a strain rate range of 1000-5000 s(-1) using a split Hopkinson pressure bar to offer theoretical guidelines for potential applications. The mechanisms of plastic deformation and dynamic recrystallization of ODS Cu were studied by analyzing the microstructure evolution during dynamic compression. The results demonstrate that the strain rate sensitivity of ODS Cu exceeds that of pure Cu, which is beneficial for resisting dynamic high-speed impacts. The accumulation of dislocations and generation of an adiabatic temperature rise during high strain rate deformation promote the splitting of the original grains and the formation of dynamically recrystallized grains. The dominant Goss and cube textures transformed into R-cube textures with increasing strain due to the continuous rotation of subgrains and recrystallized grains. By considering the coupled effects of strain and strain rate, the Johnson-Cook model was modified according to the Voce hardening law. The modified Johnson-Cook model exhibits good agreement with the experimental data across a wide range of strain rates. This study provides insight into the dynamic mechanical behavior of ODS Cu.
10.1016-j.msea.2024.147000	14	strength; properties; conductivity; electrical; mechanical; cu-; grain; mpa; electrical conductivity; aging; precipitation; phase; mechanical properties; tensile; phases	Copper-tin (Cu-Sn) serves as a prevalent alloy system in electronic packaging, envisioned for future high-power device applications. However, interdiffusion in Cu-Sn yields rigid and brittle Cu6Sn5 and Cu3Sn phases, causing joint hardening and embrittlement. This paper introduces a novel, non-homogeneous Cu-Sn composite employing heterostructure design. Through room temperature in-situ compression tests and molecular dynamics (MD) simulations, we investigate mechanical property degradation origins and Cu-Sn composite strengthductility mechanisms. Our findings reveal hierarchical heterostructures in joints stimulate dynamic stress distribution at interfaces, generating a high density of geometrically necessary dislocations (GNDs). This enhances the material's work-hardening rate and imparts robust strain-hardening capabilities. This unique structural feature has altered the interaction between dislocations and interfaces, thereby effectively promoting the formation and driving force of dislocations. The combined effects of strain inhomogeneity induced by soft and hard phases, along with a hybrid mechanism involving stacking faults (SFs), Lomer-Cottrell (L-C) locking, and dislocation bypassing and shearing, realize exceptional strength-ductility synergies in Cu-Sn composite joints. This study presents a promising paradigm for designing microstructures in high-strength, deformable, and hightemperature-resistant soldered composites.
10.1016-j.msea.2024.147070	14	strength; properties; conductivity; electrical; mechanical; cu-; grain; mpa; electrical conductivity; aging; precipitation; phase; mechanical properties; tensile; phases	This study systematically investigated the effects of a small amount of Zr addition on the microstructure evolution, mechanical, and electrical properties of Cu-Ni-Ti alloy, specifically focusing on Cu-3Ni-1Ti- (0.3Zr). The results indicate that adding an appropriate amount of Zr significantly enhances the mechanical properties and over-aging resistance of the Cu-Ni-Ti alloy, with only a slight decrease in conductivity. After aging at 500 degrees C for 2 h, Cu-3Ni-1Ti-0.3Zr exhibits an ultimate tensile strength of 673 MPa and a conductivity of 53 % IACS. Even after extending the aging time to 10 h, the tensile strength and conductivity remain high at 646 MPa and 61 % IACS, respectively. Microscopic analysis reveals that the addition of Zr promotes the formation of fine Ni3Ti phase during solidification and solution treatment, improving the deformation resistance and enhances its yield strength of the alloy in the cold-rolled state. Additionally, it hinders the migration of grain boundaries,suppressing the recovery and recrystallization processes, thus maintaining high mechanical properties and over- aging resistance. Furthermore, the precipitation of coherent or semi-coherent nano Ni3Ti phases during the aging process positively affects the alloy's yield strength and conductivity. The Oworan and dislocation strengthening mechanisms resulting from nano Ni3Ti phases are the primary mechanisms enhancing the yield strength of Cu-3Ni-1Ti-0.3Zr alloy, contributing approximately 87 %.
10.1016-j.msea.2024.147076	-1		In order to prepare the Cu-18Sn-0.3Ti alloy with excellent mechanical properties to realize the favorable collaborative deformation of Cu-18Sn-0.3Ti alloy and Nb in the preparation process of Nb3Sn 3 Sn superconducting wires by bronze method, the hot extrusion process of the Cu-18Sn-0.3Ti alloy prepared by Direct Current assisted Hot Pressed sintering based on micron atomized spherical alloy powders was systematically investigated by the combination of experiments and finite element simulation in this work. The ultimate tensile strength, yield strength and elongation can reach 683.5 MPa, 414.3 MPa and 33.3 %, respectively, through the optimization of hot extrusion parameters and subsequent solution treatment. The results show that hot extrusion with high strain rate induced the formation of fine alpha grains and dispersed delta phases. Especially, strong dislocations-annealing twins (ATs) interaction occurred, which was manifested as the pile-up of dislocations at twin boundaries of ATs, slippage of dislocations in multiple directions inside ATs and storage of dislocations inside ATs. Meanwhile, the high strain rate induced the formation of deformation twins inside partial grains. The grain refinement of alpha matrix, formation of dispersed delta phases and strong interactions of crystal defects were the main reasons for the strength-ductility enhancement of hot extruded samples, and laid an excellent microstructure foundation for further improving the mechanical properties of alloy by subsequent solution treatment. The results not only describe a feasible method for simultaneously enhancing the strength and ductility of Cu-18Sn-0.3Ti alloy, but also provide a theoretical guidance for the strength-ductility enhancement of multicomponent alloys.
10.1016-j.msea.2024.147120	-1		In this study, the Cu- 3.18Ni- 0.75Si- 0.28Cr (wt%) alloy was fabricated using vacuum-assisted die casting (VADC), and the microstructure and properties of the alloy before and after direct aging treatment were investigated. The synergistic effects of pressure and high cooling rate during the VADC process yield excellent composition uniformity within the alloy, characterized by fine-grained microstructures and the formation of a high-energy metastable supersaturated solid solution. The subsequent direct artificial aging (723 K/6 h) leads to the precipitation of nano-sized delta- Ni2Si phases, thereby enhancing both the mechanical properties and electrical conductivity of the VADC alloy. The alloy exhibited an impressive synergy of the ultimate tensile strength (659 + 14 MPa), hardness (250.7 + 3.8 HV), and elongation (21.5 + 3.6 %), with an excellent conductivity of 32.3 + 0.4 % IACS. With the considerable potential for industrial applications, the novel fabrication method enables high-efficiency preparation and near-net shape forming of high-performance Cu-Ni-Si-Cr alloy.
10.1016-j.msea.2024.147123	-1		The unusual dynamic recrystallization (DRX) behavior and microstructure evolution during compression deformation at 400-800( degrees)C of a Cu-Al2O3 alloy were investigated herein. The calculation of activation energy (Q) and critical strain for DRX (epsilon c), as well as the prediction of the volume fraction of DRX, are achieved through the construction of constitutive equations and a kinetic model of DRX. The nano-scaled Al2O3 particles are found to exert a significant pinning effect on dislocations and grain boundaries, significantly increasing the dislocation density. The Cu-Al2O3 exhibits a higher work hardening rate and stress compared to pure Cu under the same deformation conditions. The peak stresses of Cu-Al2O3 at 400( degrees)C and 800( degrees)C are 319.7 MPa and 155.4 MPa, respectively, 80.4 % and 243.1 % higher than those of pure Cu. The addition of nano-scaled Al2O3 particles reduces Q and epsilon c of DRX, promoting the transition from low-angle to high-angle grain boundaries during hightemperature deformation. Additionally, distortion zones induced by Al2O3 particles as potential nucleation sites for DRX. While the addition of these particles promotes DRX of pure Cu, the initial DRX rate of Cu-Al2O3 is suppressed by the strong pinning effect of Al2O3 particles.
10.1016-j.msea.2024.147125	-1		A novel high-strength conductive Cu-based composite, utilizing AlCrCuFeNi2.5 2.5 (Ni2.5) high-entropy alloy particles as the reinforcing phase, is synthesized through a combination of ball milling and spark plasma sintering processes. The mechanical and electrical properties of the composites are optimized by adjusting the composition. Under the synergistic effect of multiple strengthening mechanisms, the fabricated Cu-20 wt% Ni2.5 composites achieve an exceptional compressive strength of 920 MPa while maintaining an electrical conductivity of 44.3 % IACS (International Standard Copper Standard). The establishment of robust interface bonding between Ni2.5 reinforcement and Cu matrix stands as a pivotal assurance for the holistic performance of composites. Ni2.5 HEA is distinguished by good plasticity and high strength compared with traditional brittle reinforcements. An insight into the differences brought about by the distinctive dual-phase structure in terms of interfacial bonding, crack propagation, and performance is provided. It paves the way for selecting and projecting the composites for electrical contact applications, ushering in a realm of fresh possibilities.
10.1016-j.msea.2024.147136	14	strength; properties; conductivity; electrical; mechanical; cu-; grain; mpa; electrical conductivity; aging; precipitation; phase; mechanical properties; tensile; phases	The study investigates the complex relationship between precipitation patterns, microstructural evolution, and mechanical properties in a Cu-3.5Ti-0.1 Tm alloy subjected to isothermal ageing. The results reveal that ageing at 450 degrees C leads to the formation of nanoscale beta '-Cu4Ti phase particles within the grains and fibrous beta-Cu4Ti precipitates along the grain boundaries. The precipitation microstructure of this aged alloy is predominantly characterised by tetragonal beta '-Cu4Ti precipitates. During spinodal decomposition, Ti atoms segregate in rod-like Ti-rich Cu phases, facilitating their conversion into beta '-Cu4Ti phase. The beta '-Cu4Ti precipitates remain fully coherent with the Cu matrix, exhibiting a crystallographic orientation relationship of (001)Cu//(001)beta ' and [100]Cu//[130]beta '. As the precipitate radius exceeds approximately 11 nm, the elastic strain energy surpasses the energy at the precipitate/matrix interface. This leads to a shape transition from spherical to cuboidal for the beta '-Cu4Ti precipitates. Moreover, the Ti solute atoms contribute significantly to the alloy's strength through solid solution hardening, with the dissolution of 1 at% Ti solute increases the yield strength by 46.2 MPa. However, as ageing progresses from 1 to 20 h, the effect of solid solution strengthening decreases, while precipitation strengthening becomes more dominant, mainly due to the Orowan bypass mechanism. After 20 h of ageing, precipitation strengthening significantly increases the yield strength by about 436 MPa, exceeding the contributions from solid solution strengthening (78 MPa) and grain-boundary strengthening (14 MPa).
10.1016-j.msea.2024.147154	-1		The Cu-15Ni-8Sn alloy (UNS C72900) is a vital material for the manufacturing of precision instrument components. Employing the conventional process of solution treatment + large cold deformation + isothermal aging can result in a tensile strength exceeding 1200 MPa but a mere elongation of approximately 2.0 %. To enhance the reliability and service life of the Cu-15Ni-8Sn alloy, this study proposed an optimized process involving solution treatment + large cold deformation + recrystallization heat treatment + small cold deformation + heating aging to obtain low dislocation density, fine grains and precipitates, and uniform element distribution, thereby significantly enhancing the ductility while maintaining high strength . Compared to the conventional process, the total elongation under the optimized process was increased from 2.0 % to 11.7 %, while the tensile strength was slightly decreased from 1214 MPa to 1191 MPa. This study could offer optimized insights into the comprehensive mechanical property improvement of spinodal decomposition strengthened copper alloys.
10.1016-j.msea.2024.147222	-1		Inter-granular etching often leads to 'weakened grain boundaries', which deteriorate the ductility of (nano-) composites or porous materials fabricated by liquid metal dealloying (LMD). In this paper, we report that inter- granular etching can be suppressed by the addition of Zr in Ti-Ta precursor, while it is dealloyed in liquid Cu. This procedure removes grain-boundary-like defects in obtained bicontinuous Cu-Ta composites, and improve their ductility in tension. By replacing Ta with a refractory high entropy alloy (RHEA), i.e. MoNbTaVW, we also obtain high-quality bicontinuous Cu-RHEA composites with low density, high tensile strength and excellent ductility. The suppression of inter-granular etching, which is essential to the mechanical stability of LMDmade materials, might arise from the decrease of grain boundary energy of Ti-Ta precursor alloys induced by Zr addition. New materials developed in this study may enable novel applications by enlarging the property space and overcoming the poor malleability and machinability of conventional materials of this type (such as Cu-W composites).
10.1016-j.msea.2024.147242	15	aging; strength; conductivity; electrical conductivity; electrical; mpa; treatment; strengthening; degrees; cu-; cold; precipitation; tensile strength; tensile; iacs	A high strength and high electrical conductivity Cu-Cr-Zr alloy was obtained by continuous extrusion and thermomechanical treatment. Without solution treatment of the raw material, the combined process can promote the microhardness, tensile stress, and electrical conductivity to 200.4 HV0.3, 607 MPa, and 79.3 % IACS, respectively. The excellent comprehensive properties were obtained from systematically performed experiments. It was found that direct aging of as-cast or extruded alloy can not enhance the mechanical strength significantly compared with that of the extruded-rolled alloy, implying that the dislocation density plays a crucial role in the precipitation process. Cold rolling with a reduction rate of 80 % can enhance the dislocation density dramatically, promoting the precipitation process at the aging temperature of 400 degrees C. Then, the contribution of the precipitation strengthening mechanism on the total yield stress increases from 16.4 % in the extruded state to 26.4 % in the extruded-rolled-aged state. The precipitation sequence during the process was characterized as mainly meta-stable f.c.c. Cr after extrusion to stable b.c.c. Cr and Cu4Zr after thermomechanical treatment. The orientation relationship between the Cu matrix and Cu4Zr precipitates is: [011](Cu)//[100](Cu4Zr), (0 (2) over bar2)(Cu)//(040)(Cu4Zr). The investigation provides new insights into manufacturing high-performance Cu-Cr-Zr strips.
10.1016-j.msea.2024.147259	-1		Cu-Ti alloys exhibit outstanding mechanical properties and thermal stability at high temperatures, but suffer from low electrical conductivity (<15 % IACS), which severely limits their practical application. In this study, we successfully achieved large electrical conductivity of >20 % IACS, along with high strength of >1076 MPa in the Cu-3.3 wt%Ti alloy via coupling control of dislocation and multi-scale precipitates. It was revealed that compared with the traditional treatment methods, such as, aging, deformation + aging, or deformation + aging + deformation + aging, the novel method of pre-aging + cold rolling + aging, not only can greatly improve the uniform distribution level of dislocation formed during cold rolling, but can also significantly improve the formation of multi-scale precipitates and their coupling distribution with dislocations, which effectively enhance the electrical conductivity and strengthening contribution of precipitates and dislocation simultaneously. Our findings shed light on the understanding of related mechanisms in Cu-Ti alloys, certainly also provide a useful route for high strength and high conductivity of Cu alloys.
10.1016-j.msea.2024.147266	-1		The 9R phase is rarely formed in copper alloys because of its high stacking fault energy. In this study, we generated a large amount of 9R phase in Cu-0.3Zr-0.15Cr alloys by dynamic plastic deformation (DPD) at liquid nitrogen temperature for the first time, and revealed the transformation mechanism of 9R to nanotwins. The process of DPD + aging treatment enables the alloy to obtain excellent comprehensive properties (strength of 657 MPa, electrical conductivity of 75.2 % IACS, and elongation of 14.6 %), which are derived from the heterogeneous microstructure composed of ultrafine structures, coarse grains, and nano precipitated phases. In addition, we have evaluated the phase transformation kinetics after DPD at liquid nitrogen temperature. This work provides a new way to better understanding the microstructure transition and precipitation kinetics under dynamic plastic deformation with aging treatment at liquid nitrogen temperature.
10.1016-j.msea.2024.147278	15	aging; strength; conductivity; electrical conductivity; electrical; mpa; treatment; strengthening; degrees; cu-; cold; precipitation; tensile strength; tensile; iacs	This article provided a detailed study on the evolution of microstructure and properties of Cu-Ni-Fe-P alloy during thermal mechanical process. The experimental results showed that the Cu-0.3Ni-0.3Fe-0.16P alloy had an optimal comprehensive properties of tensile strength (672 MPa) and electrical conductivity (69.2 %IACS). Through charactering microstructure by the TEM, the results showed that the ultrafine precipitates were (Ni, Fe)(2)P. The pre-aging sample had a higher tensile strength and electrical conductivity in the initial stage of the final aging because the pre-aging reduced the concentration of the dissolved Ni, Fe and P solutes in the Cu matrix and increased dislocations density during the subsequent rolling. The precipitation strengthening and dislocation strengthening were two main strengthening contributions to the Cu-Ni-Fe-P alloy. The high temperature softening resistance of Cu-Ni-Fe-P alloy was above 500 C-degrees. And the softening mechanism of Cu-Ni-Fe-P alloy was significantly associated with the coarsen precipitates and the recrystallization during the high-temperature annealing. This work provided a guiding significance for the development of high-strength and high-conductivity Cu alloys.
10.1016-j.msea.2024.147302	-1		Cu-9Ni-6Sn-0.2Nb alloys were prepared by a series of preparation-process including hot rolling, solution treatment, cold rolling, annealing treatment, and aging treatment. As the results indicate, the annealing treatment provided a significant role on improving aging stability of the alloys, it obviously decreased volume fraction of DP nuclear sites as well as hinder the growth of DP colony by decreasing the degree of GND and increasing the volume fraction of Sigma 3(n) grain boundaries. Besides, annealing treatment makes Cu-9Ni-6Sn-0.2Nb alloy extend aging window, and the yield strength and Vickers hardness could nearly drop a bit after peak aging compare to the cold-rolled one. Strengthening mechanism has been quantitatively established, indicating that the respective contribution of precipitation strengthening (dominated by gamma ' phases) plays a dominant role in the strength enhancement of the annealed alloy.
10.1016-j.msea.2024.147305	14	strength; properties; conductivity; electrical; mechanical; cu-; grain; mpa; electrical conductivity; aging; precipitation; phase; mechanical properties; tensile; phases	Cu alloys strengthened with Mo nanoparticle, with Mo contents of 2 at%, 4 at%, 6 at%, 8 at%, and 10 at%, were fabricated by self-propagating high-temperature synthesis, followed by two-step hydrogen reduction and spark plasma sintering. The microstructures, mechanical properties, and thermal conductivity of these Cu-Mo alloys were investigated. The results reveal that two-step hydrogen reduction effectively reduces the average Mo particle size to 13.8 nm compared to one-step reduction. With increasing Mo content, the average grain size of Cu initially decreases but then increases due to the segregation of Mo particles. Notably, the Cu-6 at% Mo alloy exhibits the smallest average grain size of 0.46 mu m, with dispersed nanoscale Mo particles of 25.6 nm. The Cu-6 at% Mo alloy demonstrates superior mechanical properties, with a tensile strength of 405.0 MPa and an elongation of 24.9 %. Furthermore, the Cu-6 at% Mo alloy has a high thermal conductivity of 320.0 Wm(-1)K(-1) even at 400 degrees C and a high electrical conductivity of 82.3 % IACS at room temperature. This work offers valuable insights for the design of advanced Cu composites suitable for heat sink applications.
10.1016-j.msea.2024.147344	-1		With the development of information technology, machine learning (ML) has been widely applied in materials science. ML can avoid a multitude of trial and error experiments and improve the efficiency of discovering new materials. Hence, screening the alloys with excellent properties by machine learning is time-saving and effective. In this work, the major element descriptors were screened by importance analysis and correlation analysis as input features, and common ML algorithms were considered to establish ML model. The final 'composition- process-property' alloy design strategy was proposed and applied to guide the selection of alloy systems and composition. As a result, the Cu-3Ti-0.3Cr-0.15 Mg alloy was screened based on the extreme gradient boosting (XGBoost) model. The ultimate tensile strength and electrical conductivity of 1018 MPa and 20.1 % IACS were achieved for the designed alloy, respectively, which is well consistent with the predicted values. The ultra-high strength for the designed alloy can be mainly attributed to the precipitation strengthening. Specifically, the formation of nanoscale beta '-Cu4Ti '-Cu 4 Ti and Cr precipitates during the heat treatment plays a significant role in enhancing the strength of the alloy. This work offers new insights into the design of Cu-Ti alloys with excellent comprehensive properties by employing a machine learning model trained on small data sets, which also provides a potential to be applied to other materials systems.
10.1016-j.msea.2024.147345	14	strength; properties; conductivity; electrical; mechanical; cu-; grain; mpa; electrical conductivity; aging; precipitation; phase; mechanical properties; tensile; phases	The stress relaxation resistance of copper-based materials determines the reliability of contact and stable transmission of connector plugs. This study investigates the effect of trace bismuth (110 wt ppm) on the stress relaxation resistance of pure copper at temperatures of 25 degrees C, 100 degrees C, and 200 degrees C. The relationship between microstructure and stress relaxation resistance was analyzed using SEM, EBSD, and HAADF-STEM. The results demonstrate that trace bismuth significantly enhances the stress relaxation resistance of pure copper, especially at higher temperatures of 100 degrees C and 200 degrees C, where the stress relaxation rates of Cu-0.011Bi samples after 48 h decreased by 21.36 % and 18.06 %, respectively, compared to Cu samples. Trace bismuth elements exist in copper mainly in the form of double atomic layers segregated at grain boundaries, which pin the grain boundaries, inhibit grain growth, and hinder dislocation slip. At room temperature (25 degrees C), bismuth mainly improves stress relaxation resistance by refining grains. At higher temperatures of 100 degrees C and 200 degrees C, the significant enhancement in stress relaxation resistance is primarily related to bismuth's inhibition of the reduction in dislocation density and recrystallization during the stress relaxation process.
10.1016-j.msea.2024.147347	14	strength; properties; conductivity; electrical; mechanical; cu-; grain; mpa; electrical conductivity; aging; precipitation; phase; mechanical properties; tensile; phases	The exploration of the mechanical properties and microstructural evolution in Cu-9Ni-6Sn-XMn (X = 0, 0.1, 0.5, 1.0 wt%) alloys that were aged at 350 degrees C for various durations has been conducted. Spherical aberrationcorrected scanning transmission electron microscopy (AC-STEM) was utilized to characterize the nanoscale phases at the atomic scale. The results indicated that the hardness and tensile strength of the Cu-9Ni-6Sn alloy were significantly enhanced with the addition of Mn. When the Mn content was 0.1 wt% and the aging time was 720 min, the hardness and tensile strength of the alloy reached 394 HV and 883 MPa, respectively. These values were 25 HV and 84 MPa higher than those of the Mn-free alloy. The Cu-9Ni-6Sn alloy exhibits the coexistence of nanoscale D022/γ′ ordered phases throughout the aging process, which subsequently transition into discontinuous precipitation (DP). Mn effectively prevented the coarsening of the D022/γ′ ordering phases during the aging process, which may be the key factor in enhancing the strengthening effect of the alloy. It was observed that no secondary phase related to Mn was formed, as Mn was completely dissolved in the alloy. Furthermore, Mn segregated at the DP at the later stages of aging, which was attributed to the negative mixing enthalpy between Sn-Mn and Ni-Mn. The suppression of DP was related to the enhanced stability of the D022/γ′ ordering phase. These results are anticipated to provide valuable guidance for the production and application of Cu-Ni-Sn alloys.
10.1016-j.msea.2024.147356	14	strength; properties; conductivity; electrical; mechanical; cu-; grain; mpa; electrical conductivity; aging; precipitation; phase; mechanical properties; tensile; phases	The microstructural and properties of a Cu-Cr-Ni-Co-Si alloy produced by equal channel angular pressing (ECAP) were systematically investigated. After the fourth-pass ECAP deformation, the average grain size was refined from 30 mu m (solid solution state) to below 3 mu m, resulting in a fine and regularly shaped equiaxed crystalline microstructure. The distribution of grain boundaries became more uniform. During ECAP deformation, the volume fraction of Copper texture {001} <100> decreased, while that of the Brass {011} <211> increased, and the Shear {123} <634> remained nearly constant. An increase in the number of ECAP deformation passes facilitated dynamic recrystallization, leading to an increase in the fraction of the recrystallized texture. After thermomechanical treatment (first-pass ECAP +450 C-degrees aged/120 min + 80 % cold-deformation +450( degrees)C aged/ 30 min), the alloy exhibited good mechanical properties, with a tensile strength of 546 MPa, a yield strength of 475 MPa, an elongation of 18.2 %, and an electrical conductivity of 52.8 %IACS. The main strengthening mechanisms included precipitation strengthening, dislocation strengthening and grain boundary strengthening, with the precipitation strengthening accounting for 45.6 % of the yield strength .
10.1016-j.msea.2024.147370	6	grain; deformation; strain; strength; dislocation; cu-; tensile; size; ecap; grain size; sfe; ductility; hardening; high; stress	To explore the effect of persistent slip bands (PSBs) formed during cyclic loading on the static mechanical behavior of materials, [112]-oriented Cu single crystals are selected as target materials, and the tensile behavior of Cu single crystals prefatigued to the stress saturation stage at different plastic shear strain amplitudes (gamma pl) and the corresponding microstructures, surface deformation features and fracture morphologies are systematically studied. The results show that the formation of few soft PSB ladder-like structures in hard dislocation veins during prefatigue deformation at gamma(pl) = 3.7 x 10(-4) below the plateau region of cyclic stress-strain (CSS) curve can promote a synchronous improvement of strength and ductility (SISD) compared with the unfatigued crystal. As gamma pl increases to a lower value of 9.0 x 10(- 4) within the plateau region, the strength and ductility reduce sharply compared with the case at gamma(pl) = 3.7 x 10(-4) due to more concentrated plastic deformation caused by a high volume fraction of prefatigue-induced PSBs. With continuously increasing gamma pl to a higher value of 2.3 x 10(-3) within the plateau region, non-uniform dislocation distribution in labyrinth structures and the short spacing between labyrinth walls as well as the fine dislocation cells formed during tension jointly give rise to a slight increase in strength and ductility compared with the crystal prefatigued at gamma(pl) = 9.0 x 10(-4). As gamma pl is increased to the level beyond the plateau region, the ductility and ultimate tensile strength continuously increase, resulting from the co-existence of wider deformation bands and dense dislocation walls.
10.1016-j.msea.2024.147432	-1		Trace Si additions contribute to improve the mechanical properties of Cu-Cr-Mg alloys. The effect of different Si contents (0, 0.06, and 0.16 wt%) on the microstructure, mechanical, and electrical properties of Cu-0.3Cr-0.2 Mg (wt%) alloys was studied experimentally. It is found that the peak-aged with 0.06 wt% Si alloy exhibits the highest hardness and strength, mainly due to the moderate refinement of FCC-Cr precipitates by Si addition. However, excessive Si addition (0.16Si) results in the formation of Cr3Si phase, which consumes Cr elements, reducing FCC-Cr precipitation and hence degenerates precipitate strengthening. Results further suggest that the electrical conductivity decreases with increasing Si content due to the increased electron scattering. Thermodynamic calculation reveals that the nucleation driving force of Cr3Si is an order of magnitude smaller than the transformation energy from FCC-Cr to BCC-Cr, suggesting the nucleation of Cr3Si probably precedes the transformation of FCC-Cr to BCC-Cr and thereby facilitates the stabilization of FCC-Cr precipitates. This work provides an insight on understanding microstructural/property evolution of Cu-Cr-Mg-Si alloy and designing highstrength Cu-Cr-Mg alloys through Si addition.
10.1016-j.msea.2024.147473	-1		A novel layered heterogeneous microstructure, exhibiting a multiscale distribution of grain sizes and structural features, including nanocrystalline (NC), nanotwins (NT), nanoscale precipitates (NP), submicron crystalline (SC) and microcrystalline (MC), was successfully fabricated within the Cu-1Cr-0.1Zr alloy via solid solution (SS) treatment, aging treatment (AT), cold rolling (CR), and annealing treatment. The heterogeneous microstructure of the Cu-1Cr-0.1Zr alloy exhibits excellent strength, ductility, and electrical conductivity, mainly due to the synergistic effects between multi-scale grains formed during deformation, leading to significant heterodeformation induced (HDI) stress and the Bauschinger effect, which simultaneously improves strength and ductility. Interestingly, annealing treatment to form recrystallized grain, SC and MC can improve electrical conductivity. This study provides an effective way to achieve synergistic effects between significant strength, good ductility, and remarkable electrical conductivity in copper alloys.
10.1016-j.msea.2024.147477	-1		The Cu-15Ni-8Sn (wt%) based alloys exhibit an excellent combination of strength, stress-relaxation resistance and corrosion-resistance properties, and have become an important material widely used in aerospace, ocean and mining industries. So far, the mechanical behaviors of the alloys have not been understood, which limits the effective regulation of the mechanical properties of the alloys. To improve understanding of deformation mechanisms responsible for its mechanical properties, tensile tests were performed at room temperature and interrupted at the special strains to acquire deformation microstructures, and the deformation microstructures are characterized by electron backscattered diffraction and transmission electron microscopy. In contrast to pure copper in which dislocation slipping dominates the plastic deformation, the results indicate that the mainly deformation mechanism of the as-quenched Cu-15Ni-8Sn-0.18Nb alloy includes deformation twinning, dislocations slipping and generation of stacking faults (SFs), while deformation twins are inhibited in the aged sample, and dislocations and SFs dominate the deformation microstructure. The reasons for the change of deformation mechanism are due to the different stacking fault energy in the as-quenched and aged samples and the hindering effect of nanoscale precipitates to twinning in the aged sample.
10.1016-j.msea.2024.147501	-1		The trade-off of strength and ductility in the Cu alloys seriously restricts its wide application. In this study, the paradox of strength and ductility of the Cu alloy is ameliorated by rotary swaging (RS) and subsequent annealing, and reveals its microstructural evolution. It was found that the grain size was obviously refined after the RS, resulting in yield strength as high as 719 MPa but with a ductility of only 2.4 %. After annealing, the RS-350-20 sample (RS sample annealed at 350 degrees C for 20 min) exhibited partial recrystallization at the edge and middle positions, while full recrystallization occurred at the center position, which formed a gradient grain size distribution. Tensile results showed that RS-350-20 sample exhibited an excellent combination of the yield strength of 495 MPa and ductility of 27 %. High strength stemmed from residual deformation grains, recrystallized ultrafine/fine grains and heterogeneous deformation-induced (HDI) strengthening. The good ductility originated from recrystallized coarse grain, pronounced HDI hardening and activated deformation twins. In addition, microstructural characterization further revealed that dislocations were accumulated near the recrystallized grains to maintain strain continuity at the interface of deformed grains and recrystallized grains during tensile strain. With increasing strain, deformation twins were activated near the recrystallized grains, which facilitates high strain hardening capability meanwhile maintaining high strength . These findings provide insight for optimizing the strength and ductility of Cu alloys by a feasible processing.
10.1016-j.msea.2024.147534	15	aging; strength; conductivity; electrical conductivity; electrical; mpa; treatment; strengthening; degrees; cu-; cold; precipitation; tensile strength; tensile; iacs	In this study, high strength and conductivity Cu-Fe-Si-Mg alloys were produced by casting and multi-stage thermos-mechanical treatment (MTT). The electrical conductivity, yield strength, tensile strength and elongation of the Cu-2.5Fe-0.1Si-0.15 Mg alloys were 68.23 %IACS, 653 MPa, 692 MPa and 4.35 %, respectively. The addition of Mg was beneficial to reduce the generalized planar fault energy and increase the density of substructure. Meanwhile, there was a tendency for Mg atoms to segregate at the interfacial region where the second phase met the copper. The segregation of Mg effectively inhibited the growth of precipitates. There was a dramatic improvement in the ability of the second phase to pin dislocations. The overall properties of the Cu-Fe alloys were excellent. The synergistic addition of Mg and Si significantly improved the mechanical properties of the alloys, but the electrical conductivity slightly declined.
10.1016-j.msea.2024.147551	-1		Copper-based alloys possess outstanding thermal and electrical conductivity, making them popular in the electronic and aerospace industries. However, its low hardness makes it vulnerable to failure in harsh service environments, which require surface coating. By using the direct laser metal deposition method to coat harder alloys on the surface of Cu alloys, the challenge of this copper alloy's high laser reflectivity was noted. To solve this problem, both substrate preheating and high-power LMD methods were employed, which established an excellent metallurgical bonding between the coating and substrate with a 2 mu m diffusion layer and enhanced the Cu-Cr-Zr substrate's hardness and wear resistance. Due to the presence of copper elements in the fusion zone, the constituent supercooling zone is increased, resulting in a finer columnar crystal structure in the fusion zone. Such elements exchange process during LMD produces will also improve the mechanical properties of the Cu-Cr-Zr substrate by solid solution strengthening.
10.1016-j.msea.2024.147587	-1		To evaluate the reliability of the mechanical properties of alpha-brass Cu-35Zn (wt%) alloys at extremely low temperatures, we performed tensile tests at 298, 77, and 4.2 K with an initial strain rate of 1 x 10(-3) s(-1). Results showed that the yield strength, ultimate tensile strength, and tensile elongation increased as the tensile temperature decreased. Moreover, only two tensile curves obtained at 298 and 4.2 K exhibited a serrated flow. The serrations appearing at 298 K were caused by dynamic strain aging based on the interaction between diffusible Zn solute atoms and mobile dislocations, whereas those appearing at 4.2 K resulted from mechanical instability based on the edge dislocation avalanche. The increasing tensile strength with a decreasing tensile temperature originated from a combination of four different factors: 1) an increase in the yield strength because of a rise in the Peierls-Nabarro stress; 2) increases in the dislocation densities because of the suppression of dynamic recovery; 3) an increase in the number of dislocation structures due to the changes in the dislocation density and slip planarity; 4) an increase in the number of mechanical twins owing to the higher given tensile strength and lower stacking fault energy. The increase in tensile elongation with a decreasing tensile temperature was caused by the more aggressive formation of mechanical twins and dislocation structures, which caused a delay in stress localization. This aggressive formation also resulted in a finer and denser dimple morphology with a decreasing tensile temperature.
10.1016-j.msea.2024.147588	10	composites; nanoparticles; strength; matrix; high; strengthening; particles; conductivity; composite; electrical; mpa; sintering; ods; grains; mechanical	Superior mechanical and electrical properties are desired in high-strength high-conductivity Cu alloys. It is challenging to achieve strength-ductility balance and strength-conductivity balance in Cu-Ag alloys. In this work, fully nanocrystalline Cu-2.9%Ag-0.6%Zr alloy was processed by cold rolling. Aging at different temperatures was conducted to modulate the microstructures and properties. Superior mechanical and electrical properties can be achieved by aging at low temperatures. Mechanisms for optimizing the strength, ductility and electrical conductivity were discussed.
10.1016-j.msea.2024.147622	14	strength; properties; conductivity; electrical; mechanical; cu-; grain; mpa; electrical conductivity; aging; precipitation; phase; mechanical properties; tensile; phases	Understanding and regulating flow stress is crucial for producing high-performance metal thin sheets. Uniaxial tensile tests on Cu-Zn thin sheet metal reveal that the grain size at the inflection point of the size effect on flow stress (SEFS) increases with higher Zn content. This study investigates the intrinsic mechanisms affecting the SEFS, with a focus on how Zn content, grain size, and free surface influence deformation mechanism transitions in face-centered cubic metal thin sheets. Increasing Zn content reduces stacking fault energy, promotes the transition from dislocation wavy slip to planar slip and deformation twinning, increases geometrically necessary dislocation density, and mitigates SEFS. The relationship between the critical stress and strain for the onset of planar slip and deformation twinning and the square root of the grain size deviates from linearity, highlighting the size effect on the deformation mechanisms transition in metal thin sheets. This study identifies the size effects on deformation mechanisms and elucidates their underlying mechanisms. It provides new insights into controlling SEFS in metal thin sheets and lays a foundation for the design of high-performance metal thin sheets.
10.1016-j.msea.2024.147719	-1		Thin Cu foils have been adopted for current collectors in lithium-ion batteries. Nickel is commonly employed to strengthen Cu because of its low lattice mismatch with Cu. This study delves into the effect of different concentrations of Ni ions (0.0017-0.5 M) on the strength of electroplated nanotwinned (NT) Cu. Results showed that the Ni ions refined the NT-Cu films, and the optimal Ni concentration of 0.05 M was found, which maximally strengthened the mechanical strength of NT-Cu by 33.3% (up to 743 MPa). We also achieved a high international annealed copper standard (IACS) of up to 79%. Microstructure analysis reveals that the twin spacing was decreased from 70.2 nm to 21.1 nm, and the grain size was reduced from 2.67 mu m to 1.31 mu m when adding 0.05 M Ni ions in the electrolyte. Through linear sweep voltammetry (LSV), we found that the presence of Ni ions causes a negative shift in the reduction overpotential of copper, leading to the grain refinement. Confined layer slip model is also proposed to correlate the theoretical values and experimental results.
10.1016-j.msea.2024.147758	14	strength; properties; conductivity; electrical; mechanical; cu-; grain; mpa; electrical conductivity; aging; precipitation; phase; mechanical properties; tensile; phases	A novel Cu-0.3Mn-0.3Co-0.16P (wt%) alloy was developed based on the Cu-Mn-P and Cu-Co-P systems, with its microstructural evolution and properties systematically investigated during aging, cold rolling, and annealing. After aging at 500 degrees C for 4 h, followed by 80 % cold rolling reduction and annealing at 450 degrees C for 3 min, the alloy exhibited superior mechanical properties, including a tensile strength of 676 MPa, a yield strength of 660 MPa, and electrical conductivity of 65.4 % IACS. During further aging, nanoscale (Mn,Co)2P precipitates with an orthorhombic crystal structure transformed from spherical to rod-like morphologies. Strengthening was primarily driven by precipitation and strain hardening, accounting for approximately 80 % of the total yield strength . The synergistic effects of (Mn,Co)2P precipitates, refined grain boundaries, and retained dislocations resulted in an optimal balance of strength and electrical performance, indicating that the Cu-0.3Mn-0.3Co-0.16P alloy is a promising candidate for advanced engineering applications requiring both high strength and good conductivity.
10.1016-j.msea.2024.147768	14	strength; properties; conductivity; electrical; mechanical; cu-; grain; mpa; electrical conductivity; aging; precipitation; phase; mechanical properties; tensile; phases	The mechanical strength of Cu-Ag alloys can be enhanced while preserving their electrical conductivity through the addition of a third alloying element and deformation processing. This study examines the microstructural evolution of Cu-Ag and Cu-Ag-Cr alloys following cold rolling, quantifying the effects of grain boundaries, dislocations, solid solutions, and Ag precipitates on strengthening mechanisms, as well as describing the alloy's conductive behavior. The incorporation of Cr alters the precipitation behavior in Cu-Ag, promoting a predominantly continuous Ag precipitate phase. Cr addition results in a significant improvement in mechanical properties, leading to an increase in strength by approximately 140-160 MPa compared to Cr-free Cu-Ag alloys. The difference in strength between the two alloys is primarily attributed to variations in the evolution of precipitate phases at different levels of deformation, driven by a combination of dislocation and precipitation strengthening mechanisms. The reduction in electrical conductivity is mainly attributed to enhanced interfacial scattering following rolling deformation.
10.1016-j.msea.2025.147801	-1		Chemical short-range order (CSRO) plays a deciding role in the strength and toughness of medium/high entropy alloys (M/HEAs), but its participation in the design and implementation of M/HEAs is still rare. In this work, we introduce a new rationale in the design of M/HEAs in terms of CSRO using first-principles calculation and cluster variation method (CVM). The practical-to-ideal ratio in configuration entropy is proposed as the phenomenological descriptor of the CSRO effects, while pair probability of atomic interactions is used as the quantitative indicator of CSRO intensity. Taking FCC Cu-Fe-Ni MEA binder in tungsten-based composites as a typical example, the optimized Cu40Fe18Ni42 has a smaller practical-to-ideal ratio in configuration entropy, moderate phase stability and high CSRO intensity. The resulting tungsten composite achieves a balance between strength and ductility at low sintering temperatures, that is 880 +/- 4 MPa tensile strength and 28.1 +/- 0.7 % elongation. These superior mechanical properties are analyzed by elemental pair probabilities corroborated by advanced spherical aberration-corrected transmission electron microscopy, emphasizing the atomic contribution to the ductility and strength in solid solution structure. Our findings suggest that the design of M/HEAs with practical configuration entropy induced CSRO strengthening can effectively mitigate the trade-off between strength and toughness, advocating for their broader application in M/HEAs' research society.
10.1016-j.msea.2025.147805	-1		In recent years, gradient microstructures have drawn great attention due to their ability to enhance strength and ductility by manipulating microstructural features, regardless of the alloy type. This study investigates the )deformation mechanisms according to the different volume fractions of gradient regions (fg in nanotwinned (GNT) Cu specimens from abrupt to gradual transitions (fg approximate to 10 % and 100 %). This gradient region spans several transitional layers between established soft and hard components: the former consists of nanotwins within larger grains and the latter of nanotwins within smaller grains. The quantitative analysis of the additional strengthening effects attributed to varying fg has been conducted by implementing a developed dislocation-based constitutive model based on the previous experimental findings [Cheng et al Acta 242 (2023) 118,456]. The gradient effect resulted in additional nucleation of geometrically necessary dislocations (GNDs), which depended on a level of strain incompatibility at each interface of the transition layers. This finding provides a fundamental understanding of the hetero-deformation-induced (HDI) stress arising from microstructural heterogeneity in gradient structure.
10.1016-j.msea.2025.147899	-1		The derivation of mechanical properties from freestanding metallic foils requires establishing tailored characterisation methods. This study presents a novel methodology for a comprehensive mechanical characterisation of micrometric-thickness Cu-based thin foils (13-27 mu m). The approach combines Focused Ion Beam-Electron Backscatter Diffraction (FIB-EBSD) for microstructural analysis, Bulge Testing (BT) for macroscopic material properties, and Instrumented Indentation Testing (IIT) for local mechanical behaviour. The effects of alloying elements (Ni, Zn), manufacturing and thickness on the elastoplastic properties of Cu (Phosphorous HighConductivity PHC, 99.95 % wt.) were evaluated, as well as their influence on the microstructural and mechanical properties. The methodology was successfully applied to and validated for Cu-based foils, demonstrating feasibility and good agreement with the literature for elastic and plastic properties. Microstructure significantly influenced the mechanical properties of Cu-based foils. Adding Zn and Ni in Cu15Zn and Cu18Ni20Zn alloys delayed recrystallisation, while strengthening the alloyed foils compared to pure Cu and decreasing ductility. Increasing the grain size to foil thickness ratio reduced flow stress and ductility. BT proved the most suitable technique to determine plastic properties, while IIT provided reliable elastic modulus, hardness, and elastic/ plastic indentation work.
10.1016-j.msea.2025.147913	-1		In W-Cu composites, excellent mechanical and physical properties are typically mutually exclusive, presenting challenges in attaining superior overall performance. In this work, spherical W-Cu composite powders with high dispersibility and density were synthesized successfully via powder structure and morphology customization. The fine-grained W-20 wt%Cu composites with outstanding comprehensive properties through laser directed energy deposition (L-DED) technique were fabricated and the underlying mechanism of their microstructure evolution, mechanical and physical properties were revealed in detail. Herein, the prepared W-20Cu composites demonstrated improved hardness, tensile strength, thermal and electrical conductivity relative to existing literature. Specifically, the fine-grained W-20Cu composite produced at 1200 W showed a tensile strength over 500 MPa, a hardness of 261 HV, a thermal conductivity of 215.35 W/mK and an electrical conductivity of 37.93 % IACS, respectively. The strengthening mechanisms of the presented W-20Cu composites were discussed in terms of fine-grained strengthening, dispersion strengthening and a large number of sub-grains in the Cu phase. This work provides fundamental insight into developing and fabricating W-Cu composite materials with excellent comprehensive properties for demanding structural applications.
10.1016-j.msea.2025.147923	15	aging; strength; conductivity; electrical conductivity; electrical; mpa; treatment; strengthening; degrees; cu-; cold; precipitation; tensile strength; tensile; iacs	How to achieve the ultra-high strength of Cu-15Ni-8Sn alloy through process optimization without microalloying is of great significance and challenging. In this paper, the effects of solid solution + rotary swaging + aging (SRA) on the hardness, strength, and elongation of the alloy are studied by applying rotary swaging with high strain rate and large cumulative deformation before aging. The evolution law of grain orientation arrangement, twin formation characteristics, microstructure in deformation zone, and gamma (DO3) precipitation were observed and analyzed. The results show that the large deformation accumulated by rotary swaging induces a large number of deformation bands, deformation twins, and stacking faults. Deformation bands and twin boundaries provide nucleation sites for the precipitation of primary gamma (DO3) phases. During aging, the stacking faults grow into nanotwins, and the gamma (DO3) phase further dissolves and precipitates in the crystal, avoiding the grain-boundary nucleation. The tensile strength and yield strength of the SRA-treated Cu-15Ni-8Sn alloy reached 1411 MPa and 1405 MPa, respectively, and the elongation was 4 %. Compared with the conventional solution + aging process (SA), the yield strength of the alloy treated by SRA is increased by 91 % under the premise of the same elongation. The yield strength increment contributed by dislocation strengthening and layered gamma (DO3) phase precipitation strengthening accounts for 92 % of the strengthening effect of Cu-15Ni-8Sn alloy prepared by SRA process. Based on the research results of this paper, it can provide support for improving the comprehensive performance of Cu-15Ni-8Sn alloy in harsh service scenarios.
10.1016-j.msea.2025.147940	-1		Metallic materials face a dilemma of strength and ductility. Heterostructured (HS) materials provide a new paradigm for properties optimization. It has been rarely investigated for introducing multiple heterostructures in low stacking fault energy (SFE) materials. In this study, a low SFEs dual-heterostructured Cu-Zn alloy was prepared by a short time SMAT process, which has high strength and ductility matching. It has been investigated that dual-heterostructure can introduce wide geometrically necessary dislocation (GND) pileup in metallic materials, thereby generating hetero-deformation induced (HDI) strengthening and HDI hardening, dramatically improving strength and maintaining ductility. Further analysis shows that HDI strengthening mainly acts in the early stages of deformation. The low SFEs promote stacking fault and twinning, which is beneficial for maintaining the work hardening ability of the material in the later stages of deformation. The coordination of multiple mechanisms is responsible for the excellent mechanical properties of the alloy. This work provides meaningful insights into the performance optimization of HS materials.
10.1016-j.msea.2025.147949	6	grain; deformation; strain; strength; dislocation; cu-; tensile; size; ecap; grain size; sfe; ductility; hardening; high; stress	Designing heterogeneous structures in metallic materials has been reported to alleviate the paradox of strength and ductility. In the present work, Cu alloys with a bimodal grain structure were obtained by cold rolling and subsequent short annealing (500 degrees C for 10min). Tensile properties results showed that the bimodal grain structure sample exhibited 1.5 times higher yield strength and almost the same ductility as compared to the homogeneous coarse grain sample. In addition, extra strengthening and apparent heterogeneous deformationinduced (HDI) effect were observed in the bimodal grain structure sample. At the low strain stage, abundant dislocations were accumulated near the coarse grain at the interface of coarse grain and fine grain, which contributed to extra strengthening. At the tensile strain of 10 %, dislocation slip was dominated and a few deformation twins were activated near the fine grains while abundant dislocations, stack faults and deformation twins were activated near the coarse grains, which indicated that there was the strain accommodation at the interface of coarse grain and fine grain. Furthermore, the EBSD results indicated that there was strain partitioning between the fine grain and coarse grain. A superior strength-ductility synergy in the bimodal grain structure sample mainly derived from heterogeneous grains and the HDI strengthening. This work provides insight into the deformation behavior and strengthening mechanism of bimodal grain structure.
10.1016-j.msea.2025.147966	-1		Due to the high laser reflectivity, it is challenging to fabricate copper alloys with few defects and perfect forming quality by laser powder bed fusion (L-PBF). The Cu-Cr-Si alloy was fabricated by L-PBF with nearly full density, fine grains, and high performance. The optimum parameters for additive manufacturing Cu-Cr-Si alloy were obtained by orthogonal experiments. With a laser power of 450-475 W, a scanning speed of 400-500 mm/s, a hatching distance of 45 mu m, and a powder layer thickness of 30 mu m, Cu-Cr-Si alloy blocks with complete full density were fabricated, with an ultimate tensile strength of 303 MPa and an elongation of 36 %. After direct aging treatment at 500 degrees C for 45 min, the as-deposited Cu-Cr-Si alloys achieved an electrical conductivity of 63% IACS, an ultimate tensile strength of 686 MPa, and an elongation of 16 %. Refined and uniformly dispersed Cr precipitates were the main reason for the improvement of strength/hardness, and the precipitation is also effective in enhancing the electrical conductivity. This work provided theoretical guidance for the additive manufacturing of high-performance Cu-Cr-Si alloys by the L-PBF technology.
10.1016-j.msea.2025.147987	-1		Precipitate-strengthened copper alloys are widely used in lead frames and high-speed railway wires due to the enhanced strength and electrical conductivity conferred by nano-precipitates. However, the exploration of novel copper alloys only by data faces the dilemma of insufficient samples. Here we proposed a dual-drive design strategy that integrates knowledge and data for ternary precipitate-strengthened copper alloys. The knowledge from phase diagrams (PD) and open-source databases can be regarded as a dataset for machine learning (ML) models, and alloy candidates predicted by the model can be screened with maximum information using PD. The average compound formation energy, a key factor in the precipitation ability of alloying elements from the matrix, was screened out by the PD/ML dual-drive model. By exploring the composition space of 15 ternary alloys formed by the combination of 6 alloying elements and copper, we developed a Cu-0.44Ti-0.26Si alloy with tensile strength, electrical conductivity, and elongation of 741 MPa, 35.1 %IACS, and 14.0 %. This strategy can improve efficiency and accuracy in the design of precipitation-strengthened alloys with only ML or PD.
10.1016-j.msea.2025.148016	-1		Nickel bronze is provided with excellent wear and high strength, and it is widely applied to aerospace, electronics, machinery manufacturing, and communications. In this study, Cu-12Sn-2Ni alloy wires were facilitated by cold-drawn without intermediate annealing to a tensile strength of 1.3 GPa and a Vickers hardness of 425 HV. During the drawing process, the grains in Cu-12Sn-2Ni alloy are rapidly refined into nano fibers as a result of the interaction between prevailing plane defects, such as stacking faults and nano twins. Dense deformation twins are generated in the wires due to the alloy's low stacking fault energy of 18 mJ/m2. When the strain reaches 3.22, the stacking fault probability and dislocation density increase to 7.6 % and 1.88 x 1015 m- 2, respectively. Dislocation strengthening and boundary strengthening are calculated to be 468.60 MPa and 781.40 MPa in the wire at the strain of 3.22. The fibrous grain boundaries are derived from a considerable proportion of twining indicating that the strength increment by planar defects such as SFs and twin boundaries occupies the crucial position on the Cu-Sn-Ni alloy. The investigation of the strengthening mechanism of the presented Cu-12Sn-2Ni alloy offers further guidance and understanding for ultra-high strength structural metals.
10.1016-j.msea.2025.148031	-1		The influences of Co element on the microstructure and properties of Cu-W alloy were investigated, and its mechanism was discussed. Cu-W composite powders with different Co contents were prepared by mechanical alloying method, and Cu-W alloy specimens were obtained through spark plasma sintering under hot pressing. Multiple testing methods were employed to characterize the microstructure and properties of the alloy, and a theoretical model was established with the aid of the first-principles to assist the analysis. Research results demonstrate that Co is capable of participating in a solid solution reaction with tungsten. The solid solution thus formed has the capacity to hinder the migration of grain boundaries and effectuate grain refinement, consequently imposing a substantial influence on the characteristics of the alloy, including density, electrical conductivity, hardness and strength . Compared with the Cu-W alloy without the addition of Co element, when the Co addition amount is 2 at%, the hardness, tensile strength, and compressive strength of the alloy are increased by 28.7 %, 36.9 %, and 18 % respectively. Theoretical calculations indicate that the introduction of Co atoms changes the energy changes on the orbits of Cu atoms and W atoms, alters the bonding situation among neighboring atoms, and thus affects the mechanical properties of the alloy. The changing trend of mechanical properties in the theoretical calculations is generally consistent with the experimental results.
10.1016-j.msea.2025.148038	-1		High strength and high conductivity Cu-6 wt%Ag alloys have been developed as key materials for the fabrication of ultra-high pulsed magnet winding coils. Further improving the strength of the alloy wires and maintaining their high electrical conductivity are technical requirements for achieving higher pulsed magnetic fields. In this study, the rare earth element Sc was doped into Cu-6Ag alloy, while heat treatment and cold drawing deformation processing were applied. Cu-6Ag-0.07Sc alloy wire with high strength (1020 MPa), high conductivity (74.4 %IACS), and large cross-section area (12 mm2) was developed. By doping Sc, the ultimate tensile strength of the Cu-6Ag alloy was increased by 15 %, while the electrical conductivity was reduced by mere 4 %. The effects of Sc on the microstructure and properties of Cu-6 wt%Ag alloy during aging and cold drawing deformation processing were investigated systematically. The results showed that preferential enrichment of Sc at grain boundaries suppressed the nucleation and growth of the discontinuous Ag precipitates, so that promoting the continuous Ag precipitates during aging. Sc doping modulated the precipitation behavior of Ag, leading to a decrease in size and spacing of the nano-scale Ag precipitates. During cold drawing deformation, Ag precipitates evolved into Ag fibers by further decrease in scale. For the Sc-doped alloy wires, the continuous Ag fibers developed from continuous Ag precipitates increased fiber strengthening due to the more Cu/Ag phase interfaces generated by their smaller scale. In addition, the high density of ultra-fine continuous Ag fibers increased work hardening by hindering dislocation motion and reducing the size of substructures. The electrical conductivity was minimally affected by the increase in scattering. This study provides a viable strategy for achieving a balance between strength-conductivity-wire size, and promotes a more in-depth understanding of the microstructure evolution of Cu-Ag alloys.
10.1016-j.msea.2025.148055	14	strength; properties; conductivity; electrical; mechanical; cu-; grain; mpa; electrical conductivity; aging; precipitation; phase; mechanical properties; tensile; phases	Improving the mechanical properties without sacrificing the electrical conductivity of Cu-Ag alloys is of great importance due to their widespread application. In this study, a Cu-5wt%Ag alloy fabricated using powder metallurgy (PM) and casting (CA) methods were processed by cold drawing. The effects of varying cold-drawing strains on the microstructure, mechanical properties, and electrical conductivity were systematically investigated. The results revealed that after cold drawing, the PM wire exhibited finer and more dispersed Ag filaments, smaller grain sizes, and a more pronounced <111> texture compared to the CA wire. Under a cold-drawing strain of 5.42, the PM wire demonstrated a significantly higher tensile strength (1015 MPa) compared to the corresponding CA wire (864 MPa), while maintaining comparable electrical conductivity (78 % IACS). This study provides both experimental evidence and theoretical insights into the development of specialized high-strength, high-conductivity Cu-Ag alloy wire materials and offers a theoretical pathway for the development of powder metallurgy derived fine-fiber composite materials with exceptional comprehensive performance.
10.1016-j.msea.2025.148098	14	strength; properties; conductivity; electrical; mechanical; cu-; grain; mpa; electrical conductivity; aging; precipitation; phase; mechanical properties; tensile; phases	High-performance copper alloys are critical materials for next-generation electronic applications. This study investigates the effect of high-temperature pre-aging on the microstructure and properties of Cu-0.33Mn-0.31Co0.17P (wt%) alloy. Pre-aging promotes the formation of Guinier-Preston (GP) zones and nanoscale (Mn,Co)2P precipitates, reducing subsequent aging temperature and enhancing precipitation kinetics. Compared to the conventional SCA process (950 degrees C for 30 min, cold-rolled, and aged at 500 degrees C for 4 h), the SPACA process (950 degrees C for 30 min, pre-aged at 650 degrees C for 10 min, cold-rolled, and aged at 360 degrees C for 8 h) increases tensile strength by 55 MPa and electrical conductivity by 8.1 % IACS, achieving values of 715 MPa and 70.9 % IACS. This demonstrates the potential of high-temperature pre-aging for achieving a balanced enhancement of mechanical and electrical properties in copper alloys.
10.1016-j.msea.2025.148144	-1		Cu-15Ni-8Sn (wt%) is a high-performance alloy that derives its strength from spinodal decomposition and subsequent ordering. Here, the microstructural changes that occur during ageing are assessed and correlated with both elastic moduli, obtained using resonant ultrasound spectroscopy, and Vickers hardness measurements. Increases in shear modulus and hardness are observed during the initial stages of ageing and attributed to the development of a spinodally modulated structure accompanied by nanoscale D022 and γ′ ordering. With prolonged thermal exposure, discontinuous precipitation of gamma and delta phases occurs, associated with a reduction in hardness. Precipitation of gamma coincides with a marked decrease in shear modulus, whereas delta precipitation leads to an increase in the shear modulus. The findings highlight the potential of resonant ultrasound spectroscopy for the detection of microstructural changes in this alloy.
10.1016-j.msea.2025.148181	-1		This research aims to study the effect of adding Nb element on the microstructure, transformation temperatures, mechanical properties, and shape memory effect of Cu-Al-Ni-Ti alloys prepared by the vacuum arc remelting method. Various analyses, such as optical microscopy, scanning electron microscopy, and transmission electron microscopy, were used to investigate the microstructure, the differential scanning calorimetry test to study the transformation temperatures, and X-ray diffraction to study the existing phases. The obtained results showed that by adding 0.5 (wt%) Nb element to Cu-13Al-4Ni-0.7Ti (wt%) alloy with martensitic structure at room temperature, the grain size decreased from 260 to 188 mu m, and the failure stress and strain increased from 361 MPa and 6.4 % to 506 MPa and 7.9 %, respectively. Microscopic studies indicated the formation of Nb-rich second-phase particles next to Ti-rich phases in the alloy microstructure. The Cu-13Al-4Ni-0.7Ti-0.5Nb alloy (wt%) exhibited transformation temperatures Ms, Mf, As, and Af equal 110, 86, 131, and 163 degrees C, respectively. This alloy possesses a high potential for practical applications due to its 100 % recoverability with a pre-strain of 2 %.
10.1016-j.msea.2025.148192	15	aging; strength; conductivity; electrical conductivity; electrical; mpa; treatment; strengthening; degrees; cu-; cold; precipitation; tensile strength; tensile; iacs	A Cu-0.48Cr-0.4Zn-0.15In-0.1Zr (wt%) alloy with excellent comprehensive properties was designed and prepared. By optimizing the multistage thermo-mechanical treatment process, the copper alloy had tensile strength of 618 MPa, yield strength of 601 MPa, electrical conductivity of 80.2 % IACS, elongation to failure of 6.3 % and resistance to softening temperature of 562 degrees C. The main strengthening phases of the alloy were nanoscale Cr phases, and the orientation relationship between the Cr phases with coherent FCC structure and the Cu matrix in the early ageing state was the Cube-on-cube relationship. When the ageing time and temperature increased, the Cr phases gradually turned into semi-coherent or noncoherent BCC structure with N-W or K-S orientation relationship to the matrix. Synergistic addition of Zn and In elements effectively impeded atomic diffusion and grain boundary migration, inhibited the recrystallization behavior of the alloy, which improved the alloy's softening resistance. It was also beneficial to inhibit the long-range diffusion of the Cr atom, thus suppressing the coarsening of Cr phases and delaying the allotropic transition of the Cr phases from the FCC structure to the BCC structure, which in turn resulted in the excellent comprehensive performance of the alloy. Compared with Cu-CrZr alloy, Cu-Cr-Zn-In-Zr alloy under the same process treatment showed a 15.7 % increase in tensile strength, 65.8 % increase in elongation to failure and 19 degrees C increase in resistance to softening temperature, which could work as an ideal material for the lead frame in very large scale integration circuit.
10.1016-j.msea.2025.148194	10	composites; nanoparticles; strength; matrix; high; strengthening; particles; conductivity; composite; electrical; mpa; sintering; ods; grains; mechanical	This work presents a novel one-step extrusion method for preparing Al2O3 nanoparticles dispersion strengthened (ODS) copper with heterogeneous structure, overcoming the strength-ductility trade-off dilemma. Ultrafine Cu0.75 wt% Al alloy powder produced by gas-water combined atomization was processed into ODS copper powder through oxidation in air at 350 degrees C, further diffusion of oxygen in copper matrix in nitrogen at 450 degrees C, and then reduction in hydrogen at 650 degrees C. High-energy ball milled ODS copper powder was loosely sintered and subsequently extruded into ODS copper rods. The results show that the heterogeneous structure consisted of ultrafine grains in ODS copper and coarse grains in pure copper was formed after annealing of hot extruded ODS copper rods. The ultrafine grains were attributed to the strong pinning effect of Al2O3 nanoparticles on grain boundary migration, while coarse grains were due to recrystallization growth of grains derived from the sintering and hot extrusion of unexpected pure copper particles on the surface of the ODS copper powder. Owing to comprehensive strengthening mechanisms of dispersion strengthening, grains refinement, and hetero-deformation induced strengthening, compared to the as-extruded homogeneous structure, the annealed ODS copper with heterogeneous structure amazingly exhibited a 64 % increase in elongation while maintaining an excellent tensile strength of 565 MPa, significantly higher than previous work reported. These findings can provide insights into the synergistic enhancement of strength-ductility in novel copper alloys.
10.1016-j.msea.2025.148210	14	strength; properties; conductivity; electrical; mechanical; cu-; grain; mpa; electrical conductivity; aging; precipitation; phase; mechanical properties; tensile; phases	In this study, a Cu-2.3Fe-0.1Mg-0.03P alloy was developed, and the influences of Mg element on the microstructure and mechanical properties of the alloy were investigated. The Cu-2.3Fe-0.1Mg-0.03P alloy exhibited a softening temperature of 580 degrees C, a tensile strength of 506 MPa at room temperature and an electrical conductivity of 66.8 % IACS, which were higher than those of the Cu-2.3Fe-0.15Zn-0.03P (C19400), and the softening temperature was increased by similar to 100 degrees C. Through transmission electron microscopy (TEM) observations, combined with first-principles calculations and kinetic analyses, it was shown that the addition of Mg element reduced the solubility of Fe in the Cu matrix, thereby promoting the precipitation of Fe atoms, which enhanced the electrical conductivity of the alloy and increased the quantity of alpha-Fe phases. Furthermore, the incorporation of Mg element diminished the diffusion coefficient of Fe atom within the Cu matrix, consequently reducing the growth rate of alpha-Fe phase during aging. These two factors collectively enabled the alpha-Fe phases to maintain a finer, more dispersed distribution at elevated temperature, thereby impeding the recrystallization behavior of the alloy at high temperature, which primarily contributed to enhancements of both resistance to softening and strength of the Cu-Fe-Mg-P alloy.
10.1016-j.msea.2025.148239	-1		Heterostructure design has an apparent effect on mechanical properties. Cu/Ti composite plates with shuttleheterostructure (SH) were prepared by accumulative roll bonding (ARB) process. Interfacial microalloying was carried out by vacuum diffusion heat treatment comparatively, and the intrinsic mechanisms on microstructure and mechanical properties were revealed. The results show that high-density multiscale SHs are formed by Ti layers necking fracture due to the interfacial shear effect generated by ARB at room temperature. After interfacial microalloying, the elemental diffusion width at SH interfaces rises by 323 %, and a slight increase in recrystallized structures is observed. The yield strength, tensile strength and elongation are improved by 2.6 %, 10.8 % and 110 %, respectively, and the electrical conductivity is maintained at about 94 % IACS. The enhanced plastic deformability and the high level of uniform strain-hardening effect improve the plasticity of Cu/Ti composite plates. Intense metallurgical bonding at SH interfaces permits Cu/Ti composite plates to withstand greater loads for a long time. A stronger heterogeneous deformation-induced (HDI) strengthening and strain hardening effects are obtained after interfacial microalloying of SHs. It is an effective way to prepare high electrical conductivity materials with advanced strength and plasticity.
10.1016-j.msea.2025.148309	15	aging; strength; conductivity; electrical conductivity; electrical; mpa; treatment; strengthening; degrees; cu-; cold; precipitation; tensile strength; tensile; iacs	This article systematically investigated the aging behavior and precipitation of Cu-Ni-P, Cu-Fe-P and Cu-Ni-Fe-P alloys. The results showed that the novel quaternary Cu-Ni-Fe-P alloy designed based on ternary Cu-Ni-P alloy and ternary Cu-Fe-P alloy had the superior properties. The electrical conductivity and tensile strength reached 69.1 %IACS and 658.7 MPa, respectively, by the process (solution treatment + 30 % cold rolling reduction + preaging (750 degrees C x 1 min) + 30 % cold rolling reduction + aging (450 degrees C x 4 h) + 60 % cold rolling reduction + annealing (450 degrees C x 1 min)). The nanoscale precipitation (Ni, Fe)2P was a hexagonal structure in Cu-Ni-Fe-P alloy. The orientation relationship between the (Ni, Fe)2P precipitation and the matrix was [110]Cu//[111](Ni, Fe)2P, (1-1-1)Cu//(1-21) (Ni, Fe)2P. The synergistic effect of Ni and Fe atoms facilitated the precipitation of more uniform and fine phases, effectively enhancing the overall performance of NFP alloy. The synergistic contribution of dislocation strengthening and precipitation strengthening mainly driven the yield strength of alloys and were the major strengthening mechanism. The contribution of the precipitation strengthening in NFP alloy was significantly greater than that in NP and FP alloys. That was the reason for the increased strength of NFP alloy. This work indicates that the Cu-Ni-Fe-P alloy is a promising candidate for high property Cu alloys.
10.1016-j.msea.2025.148310	15	aging; strength; conductivity; electrical conductivity; electrical; mpa; treatment; strengthening; degrees; cu-; cold; precipitation; tensile strength; tensile; iacs	The high-temperature mechanical properties of Cu-Cr alloys were limited, while adding alloying elements could inhibit the coarsening of Cr precipitates and improve the high-temperature mechanical properties. The Cu-Cr-Ag and Cu-Cr-Ag-Si alloys were designed and fabricated, and their microstructure and mechanical properties were investigated to achieve high-strength and high-electrical-conductivity copper alloys. The Cu-Cr-Ag alloy treated by two-step cold rolling and aging treatment achieved an ultimate tensile strength of 620 MPa, yield strength of 600 MPa, electrical conductivity of 85.6 % IACS, and elongation of 15.7 %. Adding Si increased the high-temperature strength, room-temperature elongation, and low-temperature elongation of the Cu-Cr-Ag alloy, while decreasing the electrical conductivity, room-temperature strength, and high-temperature elongation. Nanoscale Cr particles were detected in the Cu-Cr-Ag alloy, while nanoscale Cr and Cr3Si particles co-existed in the Cu-Cr-Ag-Si alloy, among which Cr particles were the main strengthening precipitates. The curves of precipitation kinetics indicated that adding Si promoted the precipitation in the Cu-Cr-Ag alloy. Low-, room-, and high-temperature mechanical properties measurements showed that the strength variation depended on the average size of the main precipitates. The decrease in the high-temperature strength was attributed to the coarsening of the Cr precipitates. At low temperature, the average size of the precipitates was essentially the same as that at room temperature, thus the low-temperature strength was comparable to the room-temperature strength . These findings indicated that Cu-Cr-Ag and Cu-Cr-Ag-Si alloys would exhibit superior electrical and mechanical properties.
10.1016-j.msea.2025.148419	-1		Dispersion-strengthened homogeneous copper matrix composites have high strength, resulting in not only strain concentration in the later stages of deformation but also a strength-plasticity trade-off. These phenomena are absent in heterostructured (HS) materials, which are attributed to strain gradient effect and heterogeneous deformation. By modulating the distribution of WC nanoparticles and introducing heterogeneous structures, we prepared WC-reinforced copper matrix composites featuring bimodal structures, in which the WC nanoparticles of inhomogeneous distribution can effectively avoid grains coarsening by suppressing grain boundaries migration via intermittent pulsed electrodeposition and spark plasma sintering. Moreover, fracture elongation of HS Cu shows a nearly 50% improvement without any reduction in yield strength compared with ultra-fine-grained (UFG) copper-based composites. The high strength of HS Cu is attributed to HDI and dispersion strengthening mechanisms. The high plasticity of HS Cu arises from different dislocation behaviors between coarse-grained and UFG zones, which are favorable to hetero-deformation-induced hardening mechanisms, including slip transfer across heterogeneous grain boundaries, stacking fault networks, and nanotwins. Besides, a positive effect of shear bands in mitigating macroscopic strain localization is observed by digital image correlation strain field analysis. These findings shed light on the effect of dispersion-strengthened heterogeneous structures on strain dispersion and mechanical properties, thus providing a new strategy for developing high-performance copper matrix composites.
10.1016-j.msea.2025.148465	15	aging; strength; conductivity; electrical conductivity; electrical; mpa; treatment; strengthening; degrees; cu-; cold; precipitation; tensile strength; tensile; iacs	In this work, the Cu-Ni-Si alloy sheets with a thickness of 1.5 mm were prepared by constrained groove pressing (CGP) and aging treatments. The results show that the combination of CGP and aging treatments can simultaneously improve the mechanical properties and electrical conductivity of alloy. The sample subjected to 10 passes of CGP treatment and aged at 460 degrees C for 1 h exhibits optimal comprehensive properties, with a hardness of 234.8 HV, an ultimate tensile strength of 773.5 MPa, an electrical conductivity of 38.1 %IACS, and a favorable breaking elongation of 15.7 %. Compared to the peak-aged sample without CGP treatment, the hardness, ultimate tensile strength and electrical conductivity increase by 12.4 %, 15.1 % and 5.5 %, respectively. The CGP treatment can refine the grain size of alloy and increase the dislocation density, thereby promoting the precipitation of solute atoms during the aging process. The aged sample subjected to CGP treatment has a higher quantity of S-Ni2Si precipitates, and the formation of Ni3Si2 precipitates is inhibited. After aging treatment, the proportion of E3 grain boundary increases in the sample subjected to CGP treatment. Compared to random grain boundaries, the adjacent grains on both sides of E3 grain boundaries have a smaller Schmid factor mismatch, which helps to improve intergranular deformation compatibility. Moreover, the scattering effect of E3 grain boundaries on electrons is smaller. Therefore, the higher proportion of E3 grain boundary can improve the ductility and electrical conductivity of Cu-Ni-Si alloy.
10.1016-j.msea.2025.148485	-1		To adapt to harsher fusion circumstance, it is of great importance to develop a new generation of Cu-Cr-Zr-X alloy with good creep resistance for divertor in DEMO or CFETR. In this paper, the effects of Si addition on micro-structural evolution and creep behavior of Cu-Cr-Zr alloy was investigated under varying applied stresses (50-150 MPa) at 450 degrees C and 550 degrees C. The present results reveal that the steady-state creep rate of Cu-Cr-Zr alloys ranges from 10(-10) to 10(-9) s(-1) at 450 degrees C and from 10(-8) to 10(-6) s(-1) at 550 degrees C under varying stresses. In comparison, Si-containing alloys maintain a steady-state creep rate of 10(-10) s(-1)at 450 degrees C and span only two orders of magnitude, ranging from 10(-9) to 10(-8) s(-1) at 550 degrees C. In addition, the creep life of alloys containing Si is significantly higher than that of alloys without Si under identical conditions. This suggests that the creep resistance of Cu-Cr-Zr alloy can be enhanced by adding Si, primarily due to the synergistic effect of nano-sized Cr precipitates, which exhibit limited growth and stable Cr3Si intermetallic phase. These features help pin dislocation and grain boundaries, thereby obstructing their motion. This work provides theoretical guidance for the development of new creep-resistant alloys for use in the fusion field.
10.1016-j.msea.2025.148518	14	strength; properties; conductivity; electrical; mechanical; cu-; grain; mpa; electrical conductivity; aging; precipitation; phase; mechanical properties; tensile; phases	As-cast alloys with the desirable balance of strength and ductility are crucial for structural applications. We propose a hyper-gravity-assisted solidification method to intensify the primary dendrite fragmentation and achieve a reticulate-like dispersed heterostructure. Samples cast under the condition of 1500 times of earth gravity g (hereafter referred to as 1500 G) exhibit a significant improvement in strength, with yield strength increased by 198.2 % and tensile strength by 67.2 % compared to conventional 1 G casting, while maintaining 12 % fractured elongation. The strength enhancement is attributed to hyper-gravity induced forced convection of alloy melts, which intensifies primary dendrite fragmentation and promotes the formation of a dual-phase heterostructure. The refined structure, composed of a uniform distribution of primary Cu fragments and eutectic lamellae, facilitates a strain gradient at the semi-coherent Cu/Cu5Zr phase interface, localizing plastic deformation within the Cu phase. Dislocation slip and grain rotation serve as primary deformation mechanisms, with boundary interfaces constraining dislocation proliferation to synchronize strain distribution and sustain heterogeneous deformation-induced strengthening. The hyper-gravity-assisted solidification is an effective approach to tailor microstructure and enhance the mechanical properties of alloys.
10.1016-j.msea.2025.148519	14	strength; properties; conductivity; electrical; mechanical; cu-; grain; mpa; electrical conductivity; aging; precipitation; phase; mechanical properties; tensile; phases	This study comprehensively investigated the influence of Sn addition on the microstructure and properties of CuZr alloys via transmission electron microscopy (TEM), atom probe tomography (APT), along with density functional theory (DFT) calculations. The results indicate that Sn addition reduces the solubility of Zr in the solidstate matrix during solidification, increasing the formation of Zr-rich eutectic particles and refining the grains of the as-cast 0.3Sn-doped alloy. During isochronal aging, the influence of Sn on Zr-rich precipitates varies with temperature. At lower temperatures (300-350 degrees C), Sn promotes the precipitation of Zr-rich precipitates while at higher temperatures (400-450 degrees C), Sn accelerates the growth of Zr-rich precipitates. DFT simulations show that Sn atoms preferentially segregate to the Cu side of the Cu/precipitate interfaces, facilitating the formation of core-shell structured precipitates without effectively impeding precipitate growth . Regarding electric conductivity, the difference between the 0.3Sn-doped and Sn-free alloys initially decreases and then increases with rising aging temperature. This is closely related to the change in the total segregation amount of Sn atoms on Zrrich precipitates, which is associated with the size and numerical density of these precipitates. These findings offer novel insights for the composition design and processing parameter optimization of high-performance Cu alloys with core-shell structured precipitates.
10.1016-j.msea.2025.148581	14	strength; properties; conductivity; electrical; mechanical; cu-; grain; mpa; electrical conductivity; aging; precipitation; phase; mechanical properties; tensile; phases	This study utilized pulsed electrodeposition to adjust the Ni concentration in nanotwinned copper (NT-Cu) foils, successfully fabricating high thermal stability NT-Cu-Ni foils with a high ultimate tensile strength (UTS) of 782 MPa. After annealing at 400 degrees C, the strength remained as high as 550 MPa. The NT-Cu-Ni foils maintained high electrical conductivity, with the international annealed copper standard (IACS) values exceeding 74 % in the asdeposited state and increasing to over 87 % after annealing. The microstructures of the foils were carefully examined by focused ion beam (FIB) and electron backscatter diffraction (EBSD) analyses to correlate the mechanical strength to the microstructural features such as grain size, twin boundary density, kernel average misorientation (KAM), and geometrically necessary dislocation density (rho GND). The results revealed that increasing the Ni concentration in the Cu foil stabilizes the columnar twin structure, leading to a high twin boundary density and maintaining excellent strength . Recognizing that the alloy composition is a key factor that can be optimized alongside manufacturing parameters, we employed the complex system response (CSR) system to optimize the electroplating conditions, further enhancing the UTS of the Cu foil to 803.9 MPa, a 25.4 % improvement. The CSR system significantly reduces big data calculations and accelerates the experimental process, offering a fast and efficient analysis method. This approach provides an effective way for the Cu foil fabrication for lithium-ion batteries and semiconductor devices.
10.1016-j.msea.2025.148582	14	strength; properties; conductivity; electrical; mechanical; cu-; grain; mpa; electrical conductivity; aging; precipitation; phase; mechanical properties; tensile; phases	This study reports on the preparation of Cu-Cr-W alloys with varying Cr contents achieved through mechanical alloying and spark plasma sintering methods. Field emission scanning electron microscopy and transmission electron microscopy were employed to carefully observe and analyze the micro-morphological features, elemental composition, and microstructural details of the Cu-Cr-W composite powders as well as the alloy samples. The dynamic compression behaviors of Cu-Cr-W alloys under different impact rates were investigated using a Hopkinson pressure bar device. Electron backscatter diffraction was utilized to comprehensively assess the phase makeup, characteristics of grain boundaries, geometrically essential dislocation density, and inverse pole figures of the Cu-Cr-W alloy specimens after dynamic compression. Experimental results demonstrate that during the sintering process, Cr can react with the W phase to form a Cr0.5W0.5 solid solution. Additionally, the addition of Cr improves the uniformity of the dispersion of W particles in the Cu matrix. As the Cr content rises, the ability of the Cu-Cr-W alloy to resist dynamic compression improves significantly. This is mainly attributed to the synergistic effect of multiple strengthening mechanisms generated by Cr within the Cu-W alloy. For the Cu-W alloy doped with 4 at% Cr, at impact rates of 2800-3000 s-1 and 3800-4000 s-1, its dynamic compressive yield strengths reach 839 MPa and 828 MPa respectively. Compared to the Cu-W alloy without the addition of the Cr element, these values are 32.1 % and 33.8 % greater.
10.1016-j.msea.2025.148615	14	strength; properties; conductivity; electrical; mechanical; cu-; grain; mpa; electrical conductivity; aging; precipitation; phase; mechanical properties; tensile; phases	Cu-Ni-Co-Si alloys that undergo pre-aged treatment demonstrate enhanced mechanical and electrical properties, yet exhibit relatively low softening resistance (SR). Herein, 0.1 wt% Cr was doped into the Cu-1.2Ni-0.9Co-0.5Si alloy, and the effects of Cr addition on the microstructure, properties, and softening resistance were systematically investigated. The results indicate that the tensile strength slightly increases whereas the electrical conductivity remains comparable upon Cr addition under the peak-aged condition. Meanwhile, the strength decline during the over-aging stage is significantly mitigated by Cr addition, corresponding to an increase in the softening temperature from 530 degrees C to 580 degrees C. Atom probe tomography (APT) results reveal that Cr increasingly segregates at the interface between the (Ni, Co, Cr)2Si precipitates and Cu matrix as aging progresses, which contributes to the reduced growth/coarsening rate of the (Ni, Co, Cr)2Si precipitates in Cr-doped alloys. Consequently, the enhanced SR with Cr addition can be attributed to the inhibition of growth/coarsening of (Ni, Co, Cr)2Si precipitates and the resultant impediment of dislocation recovery and recrystallization during longterm aging. Additionally, the electrical conductivity of Cr-doped alloys is relatively lower than that of Cr-free alloys during the over-aging stage, which is primarily attributed to the incomplete purification of the matrix and insufficient recrystallization in the Cr-doped alloy.
10.1016-j.msea.2025.148638	-1		Cu-20 at% Ni-6.7 at% Al alloys can be strengthened through the processes of solid-solution treatment, aging, intense cold rolling, and annealing at a low temperature, that induce age hardening, deformation hardening and softening, and effective anneal hardening. This study investigated the mechanisms of deformation softening and anneal hardening at a low temperature using transmission electron microscopy, 3D atom probing, electrical resistivity measurement, and neutron diffraction. During aging at a medium temperature of 853 K (580 degrees C), fine coherent gamma'-Ni3Al precipitates with an ordered γ′ structure were dispersed in the alpha-Cu matrix, resulting in significant age hardening. In the early stage of cold rolling, deformation hardening occurred due to an increase in the dislocation density. However, in the later stage of cold rolling, the effect of deformation hardening slightly decreased as the dislocation density decreased due to dislocation annihilation. The contribution of age hardening by the gamma'-Ni3Al precipitates also decreased due to the disordering of the γ′ structure by shearing, eventually causing deformation softening. After annealing at a low temperature of 748 K (475 degrees C) for 1 min, the contribution of deformation hardening was similar to that before annealing, because the dislocation density did not decrease significantly. However, the effect of age hardening was restored due to the re-ordering of the γ′ gamma'-Ni3Al particles. Therefore, a combination of hardening by the highly dense dislocations and the re-ordering of the gamma'-Ni3Al particles resulted in an effective anneal hardening with an approximately 100 HV increase after annealing at 475 degrees C for only 1 min.
10.1016-j.msea.2025.148692	14	strength; properties; conductivity; electrical; mechanical; cu-; grain; mpa; electrical conductivity; aging; precipitation; phase; mechanical properties; tensile; phases	This study systematically investigates the influence of high-entropy alloy (HEA) particle incorporation on the microstructural evolution, interfacial bonding, mechanical properties, and electrical performance of the Cu-6 % Ag composites. The selected HEA, NbTaMoW, is a refractory HEA composed of Nb, Ta, Mo, and W in equal molar proportions (25 at% each). It was chosen due to its excellent thermal stability, mechanical strength, and toughness, making it a promising reinforcement for metal matrix composites. The composites were synthesized via mechanical alloying, cold press sintering, and subsequent rolling. Microstructural analysis reveals the presence of both micro- and nano-sized HEA particles, along with nano-sized Ag phases, all exhibiting strong interfacial bonding with the Cu matrix. The dispersive distribution of HEA particles effectively refines the grain structure in both sintered and rolled states, leading to a significant enhancement in hardness and strength with a minimal reduction in electrical conductivity. Notably, after rolling, the Cu-6 %Ag-3 %HEA composite exhibited a 66.4 % increase in hardness, a 41.7 % improvement in strength, and only an 18 % decrease in electrical conductivity. This study demonstrates that the introduction of HEA particles provides an effective strategy for optimizing the mechanical and electrical performance of Cu-based composites for advanced applications.
10.1016-j.msea.2025.148694	14	strength; properties; conductivity; electrical; mechanical; cu-; grain; mpa; electrical conductivity; aging; precipitation; phase; mechanical properties; tensile; phases	The effects of Sc addition on the mechanical properties and microstructure of a Cu-3Ni-1Ti alloy were investigated using scanning electron microscopy (SEM) and transmission/high-resolution transmission electron microscopy (TEM/HRTEM). The results show that the addition of an appropriate amount of Sc significantly enhances the mechanical properties and over-aging resistance of the Cu-3Ni-1Ti alloy. After aging at 500 degrees C for 8 h, the Cu-3Ni-1Ti-0.2Sc alloy achieves a tensile strength of 856.7 MPa and an electrical conductivity of 45.8 % IACS. Microstructural analysis reveals that the incorporation of Sc promotes the formation of (Cu, Ni)4Sc intermetallic compounds and their segregation at grain boundaries, while also facilitating the precipitation of fine Ni3Ti particles. Both phases contribute to grain refinement through pinning effects and effectively suppress recovery and recrystallization during aging. The formation of nano-sized D024-Ni3Ti precipitates during aging is identified as the key factor responsible for precipitation strengthening and improved electrical conductivity. Furthermore, dislocation strengthening and precipitation strengthening are the dominant strengthening mechanisms in the Cu-3Ni-1Ti-0.2Sc alloy, collectively contributing up to 73.5 % of the yield strength . The alloy exhibits excellent thermal stability, with a softening temperature of 640 degrees C. The decrease in hardness at elevated annealing temperatures is primarily attributed to the increased recrystallized volume fraction and the coarsening of D019-Ni3Ti precipitates.
10.1016-j.msea.2025.148741	10	composites; nanoparticles; strength; matrix; high; strengthening; particles; conductivity; composite; electrical; mpa; sintering; ods; grains; mechanical	Bulk immiscible alloys with enhanced mechanical properties face the challenge of achieving high tensile strength and proper ductility. To address this issue, nanoscale amorphous oxides were introduced into Cu-316L-Mo immiscible alloy fabricated by laser powder bed fusion (LPBF). These immiscible alloys are characterized by gamma-Fe and Cr12Fe36Mo10 (chi) particles dispersed in epsilon-Cu matrix, with a large amount of nanoscale Cr-O amorphous oxides wrapped between gamma-Fe and chi particles, which we called amorphous oxide dispersion strengthened (AODS) immiscible alloys. The formation mechanism of gamma-Fe and chi particles is liquid phase separation (LPS) in Cu-Fe system, and the in-situ amorphous oxides is induced by preferential affinity of Cr/O elements and high cooling rate. Moreover, a simple heat treatment at 600 degrees C drives Fe-rich precipitates within epsilon-Cu matrix and Cu-rich precipitates within gamma-Fe particles. As a result, the immiscible alloy after treatment exhibits high strength (similar to 897 MPa) with an enhanced elongation of similar to 6.4 %. This is the first time that a large number of in-situ generated nanoscale amorphous oxides have been used to strengthen immiscible alloys in material manufacturing. According to the research in this paper, nanoscale amorphous oxides, in conjunction with nanoscale Fe-rich particles produced by liquid-phase separation, can provide a enhancing strength and ductility for Cu-Fe immiscible alloys. These result may offer a new strengthening method for all alloys with Cr-containing produced by additive manufacturing, that is, enhancing the strength and ductility of alloys by in-situ nanoscale amorphous oxides.
10.1016-j.msea.2025.148816	-1		In this study, the combination of continuous extrusion and rolling process was proposed to manufacture dilute Cu-Cr-Zr strips. Without any heat treatments, the manufactured Cu-0.8Cr-0.06Zr alloy exhibits excellent properties, with a tensile strength of 554.9 MPa and an electrical conductivity of 80.3 % IACS. The substantial grain refinement, dynamic precipitation, and dislocation multiplication during this process can be the reasons for the enhanced mechanical and electrical properties. Consequently, no further aging treatment is required.
10.1016-j.msea.2025.148850	-1		With the rapid development of lithium-ion battery industry, the high energy density design of lithium-ion batteries put forward higher requirements for the strength and ductility of ultra-thin copper foils when used as an anode collector. However, the dilemma of trade-off between strength and ductility remains a significant obstacle for ultra-thin copper foils due to the undesirable dislocation storability. In this work, we designed a heterogeneous bimodal structured copper foil with both coarse and fine nano-grains by direct current electrodeposition for large-scale production through optimization of the additives and processing parameters. The tensile test results showed that the as-prepared ultra-thin copper foil exhibited high yield strength (586.3 MPa), ultimate tensile strength (623.5 MPa), and uniform elongation (5.82 %), which can be mainly attributed to the formation of strain gradients at the fine and coarse ultra-fine grains interface resulting from the bimodal heterogeneous structure. In addition, the accumulation of high-density geometrically necessary dislocations at the interface could effectively suppress the strain localization in subsequent plastic deformation, which could maintain the strengthening effect induced by high heterogeneous deformation. These findings indicate a novel mechanism for the preparation of superior ultra-thin copper foils with high strength and ductility.
10.1016-j.msea.2025.148873	6	grain; deformation; strain; strength; dislocation; cu-; tensile; size; ecap; grain size; sfe; ductility; hardening; high; stress	Gradient structured (GS) materials have been widely investigated due to its prior property, and the stacking fault energy (SFE) has a significant impact on microstructural evolution and mechanical properties of GS materials. Herein, GS Cu, Cu-30 %Zn and Cu-38 %Zn alloy were prepared by means of surface mechanical attrition treatment (SMAT) at room temperature. TEM observation revealed that the topmost surface possessed an amount of defects, e.g., dislocation, deformation twin. Furthermore, the plastic deformation mechanism gradually changes from dislocation subdivision domains to the twin fragmentation domains with the SFE decreases. Mechanical properties showed that the Cu-38 %Zn alloy achieved the superior combination of strength and ductility, which can be attributed to the hetero-deformation induced (HDI) strengthening, and the generated deformation twins and HDI strain hardening can lead to the superior ductility. The present study can provide new avenue to design and manufacture metallic material with desirable mechanical properties.
10.1016-j.msea.2025.148894	15	aging; strength; conductivity; electrical conductivity; electrical; mpa; treatment; strengthening; degrees; cu-; cold; precipitation; tensile strength; tensile; iacs	In this paper, the influence of cold drawing deformation (0 %, 10 % and 36 %) on the grain characteristics and mechanical properties of Cu-15Ni-8Sn-0.2Nb alloy in solid solution was studied. With the increase of cold deformation, the grains are gradually elongated along the axial direction, and the dislocation density and the number of deformation twins are increasing continuously. When 36 % cold deformation is applied, the tensile strength of Cu-15Ni-8Sn-0.2Nb alloy is 865.3 MPa, which is 49.3 % higher than that of solid solution state, and the elongation at this time is 9.9 %. On this basis, the aging precipitation behavior of Cu-15Ni-8Sn-0.2Nb alloy after 36 % cold deformation was further studied after holding at 400 degrees C for different times (30 min, 60 min, 120 min, 240 min, 480 min, 600 min). The evolution law of microstructure characteristics such as dislocations, precipitates and twins during cold deformation aging was proved. It is found that the cold deformation before aging promoted the growth of ordered phases of D022 and γ′. After 36 % cold drawing deformation and aging treatment at 400 degrees C for 60 min, the tensile strength of Cu-15Ni-8Sn-0.2Nb alloy reaches the highest value of 1284.1 MPa and the elongation of 5.4 %. Compared with the conventional solution + aging process, the tensile strength of the alloy is increased by 24 %. The increase of dislocation density induced by cold deformation aging and the precipitation of NbNi3 phase, as well as the coexistence of nanotwins and ordered phases, are the dominant factors to achieve ultra-high strength .
10.1016-j.msea.2025.149022	14	strength; properties; conductivity; electrical; mechanical; cu-; grain; mpa; electrical conductivity; aging; precipitation; phase; mechanical properties; tensile; phases	Enhanced mechanical and electrical conductivity of low alloyed Cu-Sc alloys were systematically investigated with a focus on precipitation, solid solution, and dislocation strengthening. A Cu-0.27 wt% Sc alloy subjected to 50 % cold rolling and peak aged for 0.5 h at 450 degrees C achieved a high yield strength of 434 MPa and a conductivity of 42.5 MS/m (73.3 % IACS). The microstructural evolution during aging was characterized by SEM, TEM, and APT, revealing the rapid formation of nanoscale, plate-like Cu4Sc precipitates growing with increasing aging time. The enhanced precipitation response in cold-worked conditions was attributed to dislocation-assisted nucleation and solute flux driven by strain fields. A mechanistic strengthening model incorporating work, solid solution, and particle hardening accurately predicts the time-dependent mechanical response. The results underline the capability of Sc as an effective alloying element for high-strength, high-conductivity copper alloys. Based on the observed kinetics and mechanisms, a multi-stage thermomechanical treatment involving intermediate deformation steps is proposed to further exploit this strengthening potential.
10.1016-j.msea.2025.149057	14	strength; properties; conductivity; electrical; mechanical; cu-; grain; mpa; electrical conductivity; aging; precipitation; phase; mechanical properties; tensile; phases	Cu-Cr-Nb alloys have garnered considerable attention for extreme thermal applications due to their exceptional combination of high strength and electrical conductivity. In this work, Cu-4 at%Cr-2 at%Nb alloy was fabricated by selective laser melting and subsequently heat-treated to establish a multi-level dual heterostructure. The as-built material displayed a bimodal grain morphology, with coarse columnar grains occupying the melt-pool cores and fine equiaxed grains at overlapping boundaries, all reinforced by dispersed submicron Cr2Nb precipitates (similar to 37.5 nm). Direct aging at various temperatures revealed that a 2 h hold at 450 degrees C produced the optimal balance of hardness (similar to 258 HV0.3) and conductivity (similar to 46 % IACS). Under peak-aged state, the alloy exhibited an ultimate tensile strength above 900 MPa with similar to 14 % elongation, outperforming analogous Cu-Cr systems. Microstructural analysis showed that aging also generated coherent Cr nanoparticles (similar to 4.9 nm), forming a dual-scale precipitate distribution. The results from in-situ tensile observations, together with electron microscope analysis, indicated that strain localized and stress concentrated near melt-pool boundaries, where fine grains and high dislocation densities promoted heterogeneous deformation. Quantitative strengthening calculations demonstrated that, in addition to the retained dispersion strengthening and dislocation hardening from Cr2Nb, significant Cr precipitation contributed to the overall strength . Furthermore, hetero-deformationinduced back stresses enhanced the work-hardening rate. These synergistic effects of bimodal grains and dual precipitates offer a promising strategy for designing next-generation copper alloys that achieve a superior strength-ductility-conductivity combination.
10.1016-j.msea.2025.149073	-1		In this work, the microstructure and performance of Cu-Ta-W alloy with the variation of Ta content and correlative mechanism were studied. FESEM, TEM, EDS and EBSD were employed to characterize the microstructure of Cu-Ta-W alloy. Moreover, the compression properties, tensile properties, electrical conductivity, hardness, and electrical contact properties were systematically investigated. The results show that, incorporating Ta element into Cu-W alloy system can exert a substantial refining influence, with the formation of solid solution Ta0.5W0.5, which has the ability to pin Cu grains with great effectiveness. The number of grain boundaries can be significantly increased, which has an impact on the properties Cu-Ta-W alloy. When Ta content is 2 at%, the tensile yield strength and compressive yield strength of Cu-Ta-W alloy can reach 386 MPa and 403 MPa, demonstrating 19.1 % and 23.6 % higher than those of Cu-W alloy without Ta, respectively. When Ta content increases from 0 at% to 3 at%, the elongation significantly surges, escalating from the starting value of 6.4 %- 13.3 %, marking an approximate increase of 107.8 %. The electrical contact stability of Cu-Ta-W alloy can be significantly improved by adding Ta. And the material transfer amount and mass loss can be greatly reduced during the electro-corrosion process, ensuring the maintenance of the performance stability of Cu-Ta-W alloy. The relevant internal connections between microstructure and performance of Cu-Ta-W alloy are analyzed in depth in the paper. This research might provide certain impetus for the development of high-performance Cu-W alloy.
10.1016-j.msea.2025.149108	14	strength; properties; conductivity; electrical; mechanical; cu-; grain; mpa; electrical conductivity; aging; precipitation; phase; mechanical properties; tensile; phases	Achieving concurrent enhancement of strength and electrical conductivity in copper-based composites remains a longstanding challenge due to their intrinsic trade-off. In this study, dual-heterogeneous layered Cu/Cu-6 % Ag-HEA composites were fabricated by accumulative roll bonding (ARB), incorporating 1 wt% and 3 w % high-entropy alloy (HEA) powders. The Cu/Cu-6 %Ag-3 %HEA composite exhibited an optimal property balance, achieving a tensile strength of 558 MPa, uniform elongation of 16 %, and electrical conductivity of 81 % IACS. Detailed microstructural characterization revealed that the superior performance arises from the synergistic effects of alternating heterogeneous layers, uniformly dispersed HEA and Ag nanoparticles, continuous electron transport networks, and reduced electron-scattering interfaces. This layered architecture effectively alleviates the conventional strength-conductivity dilemma in copper alloys. The present work not only demonstrates a simultaneous improvement in strength-ductility and strength-conductivity combinations but also establishes a new design strategy for advanced Cu-based layered composites.
10.1016-j.msea.2025.149115	14	strength; properties; conductivity; electrical; mechanical; cu-; grain; mpa; electrical conductivity; aging; precipitation; phase; mechanical properties; tensile; phases	The microstructure evolution and comprehensive property mechanisms of the Cu-3Ti-0.3Cr-0.15Mg-xSc (x = 0, 0.08, 0.15 wt%) alloys were systematically investigated. The addition of Sc results in a certain degree of refinement of the grains and improves the strength and plasticity of the alloy. Meanwhile, Sc induced the precipitation of nanoscale Cu4Sc, which endowed a synergistic strengthening effect with the original (3 '-Cu4Ti and Cr precipitates. In addition, the addition of Sc contributes to hinder dislocation motion and enhance the strength of the alloy. Precipitation kinetic equations were established for Cu-Ti-Cr-Mg-Sc alloys, demonstrating that Sc addition accelerated the precipitation process. The electrical conductivity, hardness, ultimate tensile strength and elongation of the 0.15Sc alloy is 14.08% IACS, 381.03 HV, 1164 MPa, and 6.5%. Sc addition improves the comprehensive properties of Cu-Ti alloys, providing novel design strategies for composition optimization of Cu-Ti alloys.
10.1016-j.msea.2025.149139	-1		Cu-Al-Mn shape memory alloys (SMAs) are valuable for their large transformation strain and wide temperature range. However, high-performance Cu-Al-Mn alloys are typically single-crystalline or columnar-grained, while their polycrystalline, multi-variant alloys often exhibit limited pseudoelasticity with unfavorable reversibility due to the low yield strength . Here, fine-grained Cu-Al-Mn alloys were fabricated via laser powder bed fusion (L-PBF), and their deformation mechanisms were studied using in-situ tensile test. In-situ optical microscopy tensile testing was used to reveal distinct types of surface reliefs, including parallel bands, linear stripes, slip traces, and cracks. A multi-scale analysis was conducted to correlate these features with their underlying physical mechanisms. The formation and disappearance of parallel surface relief corresponds to the forward and reverse stress-induced martensitic transformation (SIMT). In contrast, the linear surface relief observed at grain boundaries arise from grain rotation driven by the strong anisotropy of the Cu-Al-Mn alloys. Furthermore, the activation of the {111}<011> slip system within the grains leads to the formation of slip traces, followed by the initiation of microcracks due to the operation of a new kind of <111> slip, ultimately resulting in material failure. These findings suggest that enhancing pseudoelasticity requires strengthening the matrix to suppress dislocation glide and grain rotation, thereby providing a theoretical basis for designing high-performance, fatigue-resistant Cu-Al-Mn alloys.
10.1016-j.msea.2025.149151	14	strength; properties; conductivity; electrical; mechanical; cu-; grain; mpa; electrical conductivity; aging; precipitation; phase; mechanical properties; tensile; phases	Cu-Cr alloys, owing to their excellent electrical conductivity and high strengthening potential, have broad applications in high-performance electrical engineering materials. In this study, a synergistic microstructural regulation strategy combining room-temperature rotary swaging (RS) with subsequent aging was proposed to construct a load-bearing-conduction compatible architecture, enabling simultaneous enhancement of strength and electrical conductivity in a Cu-Cr alloy (0.5 wt% Cr). The RS process induced pronounced axial grain elongation (aspect ratio approximate to 11) and promoted the enrichment and ordered arrangement of dislocations along microband boundaries, thereby forming a localized substructural network that integrates high-density strengthening with low-scattering conduction. Concurrently, RS accelerated Cr precipitation and facilitated a transition of precipitate-matrix interfaces from coherent to incoherent, significantly mitigating interfacial scattering. In addition, partial discontinuous dynamic recrystallization generated low-distortion grains, further optimizing electron migration pathways. As a synergistic outcome of these mechanisms, the yield strength increased from 404 MPa to 494 MPa, while the electrical conductivity improved from 71.3 % IACS to 82.2 % IACS. This dislocation-interface synergy overcomes the traditional trade-off between strength and conductivity, and, owing to the efficiency and scalability of the RS-aging process, offers a viable route for high-performance microstructural design and large-scale production of Cu-based alloys.
10.1016-j.msea.2025.149156	14	strength; properties; conductivity; electrical; mechanical; cu-; grain; mpa; electrical conductivity; aging; precipitation; phase; mechanical properties; tensile; phases	Caliber rolling (CR) is a extensively employed in the mass production of fine-grained metals, with applications spanning various industrial fields. This study investigates the effects of multiple caliber rolling passes on the microstructural evolution and mechanical properties of pure copper (Cu) at ambient temperature. The results indicate that CR effectively refines grain size, predominantly through the fragmenting the original grains. After 3 passes, the average grain size (AGS) decreases, leading to enhanced mechanical properties, i.e., the yield strength (YTS), ultimate tensile strength (UTS), and elongation (El.) of pure Cu are 171 MPa, 430 MPa, and 17.7 %, respectively. In comparison to as-extruded one, the YTS and UTS exhibited increases of 54.4 % and 51.2 %. The improvement in mechanical properties is primarily attributed to grain refinement and dislocation strengthening mechanisms. However, after 5 passes, the influence of grain refinement becomes more significant than dislocation strengthening, resulting in a decline in strength .
10.1016-j.msea.2025.149160	-1		CuSnTi alloy plays a crucial role as the primary raw material in preparing Nb3Sn superconducting wires. The alloy requires a long period of solid solution treatment to eliminate segregation, increase the Sn solid solution content and improve the properties of the alloy's mechanical properties, and thus Nb3Sn's superconducting properties, but this will causes a series of problems such as oxidation, properties degradation, and even cost. In this work, a CuSnTi alloy with a strength of 500 MPa and an elongation of 70 % was successfully developed for the first time via rotary forging combined with heat treatment. The effects of different rotary forging deformation amounts and solution times on the microstructure and properties were studied. The results show that the formation of recrystallization nuclei accelerates the diffusion of elements, thereby promoting the dissolution of the delta phase, and this in turn promotes the growth of recrystallization nuclei. The improvement of the mechanical properties of the alloy is related to grain boundary strengthening. This work improves the properties of CuSnTi alloy on the basis of saving costs and simplifying production process, and also lays a solid material foundation for the preparation of high properties Nb3Sn superconducting wires.
10.1016-j.msea.2025.149163	-1		The discovery of novel metallic alloys with superior properties for structural applications is needed to address current challenges and enable technological advances. However, high-throughput fabrication of structural materials to explore a broad range of new chemistries is difficult using conventional bulk processing methods. Combinatorial sputter deposition of thin films is commonly used to rapidly explore wide compositional spaces for functional materials but typically produces fine-scale, columnar microstructures that differ from bulk counterparts and remain fixed to a substrate. Here, we demonstrate that a combination of sputter deposition, thermal annealing, and mechanical processing can be used to fabricate thick, free-standing foils with bulk-like microstructures for use in alloy design and discovery. To evaluate this concept, we selected pure copper as a model system, given its well-documented physical and mechanical properties and the extensive prior research available for meaningful comparison. Specifically, we sputter-deposit 200 mu m thick Cu foils, remove them from their substrates for thermal and mechanical processing, and show that their mechanical and physical properties closely resemble those of conventionally processed bulk Cu foils.
10.1016-j.msea.2025.149200	14	strength; properties; conductivity; electrical; mechanical; cu-; grain; mpa; electrical conductivity; aging; precipitation; phase; mechanical properties; tensile; phases	Single-crystal copper processing wire as a critical conductive material for transmission wires in integrated circuits, plays an essential role in ultra-fine processing due to its superior plastic deformation capability. This study investigates the evolution of plastic deformation and microstructural changes in single-crystal copper processing wire under high strain conditions with the addition of the rare earth element Y. Furthermore, the influence of the rare earth element Y on the mechanical properties, microstructure development, and texture composition of single-crystal copper processing wire is systematically examined. The study employed scanning electron microscopy (SEM), electron backscatter diffraction (EBSD), X-ray diffraction (XRD), three-dimensional atom probe tomography (3D-APT), and transmission electron microscopy (TEM) for material analysis and characterization. A Y-O atomic mutual attraction model was developed to analyze the nanoscale precipitated phases. The results indicate that a Y-O '' phase forms at epsilon >= 3.68, accompanied by a self-annealing phenomenon. Specifically, during room temperature plastic deformation, the tensile strength of Cu-0.03Y processing wire (291.73 MPa) decreases by 35.4 %, while its elongation(5.75 %) increases by 751 % compared to that of single-crystal copper processing wire (0.675 %). The presence of multi-scale precipitates, including nanoscale Y2O3 and micron-scale Cu5Y precipitates, in micro-alloyed single-crystal copper processing wires induces significant lattice distortion and enhances the cumulative dislocation density. The high dislocation density facilitates dislocation reorganization, subgrain rotation, and the transition from LAGBs to HAGBs, thereby increasing the volume fraction of <100> and <110> fiber textures and promoting recrystallization.
10.1016-j.msea.2025.149201	14	strength; properties; conductivity; electrical; mechanical; cu-; grain; mpa; electrical conductivity; aging; precipitation; phase; mechanical properties; tensile; phases	In precipitation-strengthened alloys, hardenability directly affects the uniformity of microstructure and mechanical properties. Traditionally, copper alloys are considered to have excellent thermal conductivity and are thus not expected to exhibit significant hardenability issues. However, this study reveals a counterintuitive phenomenon. In end-quenching experiments on a Cu-15Ni-8Sn-0.26Nb alloy, the hardness and strength of the asquenched alloy increase with increasing distance from the quenched end, while the elongation significantly decreases. Microstructural analysis indicates that alloys farther from the quenched end exhibit more pronounced spinodal decomposition within the grains. D022 and γ′ ordered phases precipitate in the region of the alloy farther from the quenching end. Spinodal structures and nanoscale ordered phases contribute significantly to enhancing the hardness and strength . Simultaneously, the number and size of second-phase particles precipitated at grain boundaries increase with distance from the quenched end. These particles promote microcrack initiation and propagation, ultimately leading to reduced ductility. After aging treatment, the hardness and strength become relatively uniform along the length of the end-quenched specimen, showing no significant dependence on the distance from the quenched end. However, the elongation remains to decline significantly. This is attributed to the formation of high-density nanoscale D022 and γ′ ordered phases within grains at all positions, which elevate the hardness and strength to their peak levels. Meanwhile, the second-phase particles at the grain boundaries further increase in size and amount on the basis of those formed during quenching. This exacerbates microcrack initiation and propagation during tensile deformation, leading to a further reduction in ductility.
10.1016-j.msea.2025.149202	14	strength; properties; conductivity; electrical; mechanical; cu-; grain; mpa; electrical conductivity; aging; precipitation; phase; mechanical properties; tensile; phases	Ultrafine (30 mu m diameter) Cu-2wt%Ag alloy wires were fabricated by cold drawing directionally solidified <111>-oriented single-crystal rods (phi 6 mm) to a total deformation of 99.998 %. This study systematically investigates the evolution of texture, mechanical properties, and strengthening mechanisms, revealing significant heterogeneity in texture development across the wire's cross-section. The central region evolved from its initial <111> orientation to a dual <111>+<100> texture, with the <100> component arising from deformation band fragmentation. In contrast, the texture evolution in the edge region was more complex: at low deformation, deformation bands with <112> orientations formed with threefold rotational symmetry; at high deformation, these bands rotated to a <100> orientation, resulting in a final <111>+<100> texture. Concurrently, the matrix <111> component was stabilized via a <111>-><110>-><111> rotation path . The final 30 mu m wire exhibited an excellent combination of high tensile strength (955.8 MPa) and good electrical conductivity (80.3 % IACS). Quantitative analysis identified grain boundary, dislocation, and texture strengthening as the primary strengthening mechanisms, while the proliferation of transverse grain boundaries was identified as the primary contributor to the increase in electrical resistivity.
10.1016-j.msea.2025.149221	14	strength; properties; conductivity; electrical; mechanical; cu-; grain; mpa; electrical conductivity; aging; precipitation; phase; mechanical properties; tensile; phases	Cu-Fe alloys, also a type of metal matrix composites, are known for integrating Cu's high electrical conductivity and Fe's strength as well as magnetic properties. However, their metastable immiscibility leads to phase segregation and coarse dendrites during conventional casting. This study employs magneto-Archimedes levitation to prepare Cu-5wt%Fe alloy ingots with a homogeneous microstructure and minimal macro-segregation. Subsequent dual-stage thermomechanical treatment (DSTT), combining rolling and aging, optimizes mechanical and electrical properties. Heat treatment at varying strain stages refines dislocation density and promotes Fephase precipitation. The resulting alloy achieves a tensile strength of 504 MPa and conductivity of 41.32 % IACS, attributed to precipitation, dislocation, and grain boundary strengthening. The method overcomes the challenges of phase segregation and maintains the balance between strength and conductivity. This work provides a scalable method for producing high-performance Cu-Fe immiscible materials.
10.1016-j.msea.2025.149241	6	grain; deformation; strain; strength; dislocation; cu-; tensile; size; ecap; grain size; sfe; ductility; hardening; high; stress	Heterogeneous structure metallic materials have been reported to exhibit outstanding mechanical properties. In this study, dual heterogeneous structure with gradient deformation structure along depth and bimodal grain structure at the center in the Cu alloys was obtained by cold rolling and annealing, and subsequent surface mechanical attrition treatment. The mechanical properties and deformation behaviors of single gradient structure and dual heterogeneous structures samples were compared. The CR-350-15+SMAT sample with dual heterogeneous structure exhibited excellent tensile properties with a yield strength of similar to 260 MPa and uniform elongation (UE) of similar to 30 %, which is superior to that of the CR-600-15+SMAT sample with a single gradient structure (YS of 210 MPa and UE of 32 %). In addition, the higher hetero-deformation induced (HDI) strengthening was produced in the dual heterogeneous structure sample than that of the single gradient structure sample, which is attributed to the introduction of the high-density heterogeneous structure interfaces. Microstructure characterization revealed that hierarchical deformation twins along depth and dislocations accumulation at heterogeneous interface of coarse grain and fine grain at center region were activated during tensile strain, thereby increasing the yield strength meanwhile maintaining high ductility. Furthermore, strong and dispersed strain bands were produced on the SMAT surface of the CR-350-15+SMAT sample due to the stronger interaction of gradient structure and bimodal structure. This dual heterogeneous microstructure strategy provides a promising way to achieve strength-ductility synergy in the Cu alloys.
10.1016-j.mseb.2006.02.064	2	corrosion; surface; film; electrochemical; films; spectroscopy; layer; current; solution; potential; resistance; composition; x-ray; ions; showed	Films of La2Zr2O7 (=LZO) have been formed by chemical solution deposition technique (CSD) on new bi-axially textured Cu-Ni alloy tapes based on rolled constantan (CU55Ni45) Rabits. The precursorused was acetylacetonates treated in propionic acid (0.1-0.87 mol/l) and then deposited by spin-coating. The LZO film starts to crystallize above 850 degrees C, the film nucleates bi-axially textured on the substrate (with unit cell axis rotated 45 degrees from those of the substrate). The top part of the film is not textured even after long annealing time at 1100 degrees C, but the interfacial part is bi-axially textured. Thus, synthesis of bi-axially textured films on Cu55Ni45 Rabits seems possible but more works are needed to optimize its properties.
10.1016-j.mseb.2007.09.064	11	glass; bulk; metallic; bulk metallic; gfa; bmg; glassy; metallic glass; ability; bulk metallic glass; amorphous; addition; crystallization; mm; glass-forming	New Cu-Zr-based glassy alloys with an unusual glass-forming ability (GFA) were synthesized in the Cu-Zr-Ag-Al system, based on a ternary Cu45Zr45Ag10 alloy. The quatemary alloys exhibit large supercooled liquid region of 75-108 K and high-reduced glass transition temperature of 0.581-0.610. The best GFA was obtained for Cu36Zr48Ag8Al8 alloy, from which bulk glassy samples of up to 25 mm diameter were successfully fabricated by an injection mold casting method. The bulk glassy alloys exhibit high-compressive fracture strength of 1836-1981 MPa with plastic strain of 0.1-1.0% and excellent corrosion resistance in 1N H2SO4 solution.
10.1016-j.mseb.2009.11.003	-1		The present study concerns correlation of microstructure and magnetic properties of nanocrystalline binary 50Cu-50Co and ternary 50Cu-25Co-25Ni (wt%) alloys prepared by ball milling and subsequent isothermal annealing of the ball milled alloys. High resolution transmission electron microscopic (HR-TEM) investigation has shown deformation-induced microstructural features. Field emission scanning electron microscopy (FE-SEM) has revealed a distinct change in morphology of as-milled CuCoNi alloys after annealing. Differential scanning calorimetric (DSC) and X-ray diffraction (XRD) analysis have revealed that annealing of the CuCoNi alloy above 350 degrees C results into precipitation of nanocrystalline Co (fcc) in the CuNi matrix by spinodal decomposition. It is also demonstrated that isothermal annealing of the ball milled alloys in the temperature range between 350 and 650 degrees C significantly influence the magnetic properties, e.g. coercivity (H-c), remanence (M-r) and magnetic saturation (M-s) due to annihilation of defects such as stacking and twin fault along with dissolution and/or precipitation of magnetic phases in the Cu-rich matrix.
10.1016-j.mseb.2010.01.058	-1		Ternary Cu-Zn-Al alloys show good shape memory properties with narrow hysteresis and a wide range of martensitic transformation temperature (M-s) depending on the alloy composition. Thin films of Cu-Zn-Al with shape memory effect were grown for the first time using a new procedure. First Cu-Al thin films were obtained by DC sputtering on Si (1 00) substrates at room temperature, and second, the Cu-Al films were encapsulated and annealed in the presence of a Cu-Zn-Al bulk reference in order to fix a Zn vapour pressure. In this way a controlled amount of Zn is transported from the bulk reference into the film, in such a way that the M-s of the film becomes nearly the same as the bulk reference. The structures and microstructures of the as grown films were analysed by X-ray diffraction and transmission electron microscopy. The martensitic transformation temperature was determined by resistivity measurements.
10.1016-j.mseb.2010.02.004	-1		Useful functions of hydrogen found recently in materials are reviewed with newly obtained results. By hydrogen absorption-desorption heat-treatment, grain size of Cu-Ti alloys are refined to several 10 nm. Simultaneous improvements of electrical conductivity and mechanical strength for Cu-3 mass%Ti alloy were achieved, and the values of 21%IACS and 1100 MPa were obtained, respectively. Hydrogen treatment led to a reduction in the grain size in alpha- and beta-rich alpha + beta type alloys to about 3 and 0.3 mu m, respectively. The yield strength of fine-grained alpha- and beta-rich alpha + beta type alloys is greatly improved. Curie temperature of La(FexSi1-x)(13) compounds is controlled by the content of hydrogen. It is also demonstrated that the La(FexSi1-x)(13)H-y compounds can be applicable as new-type pressure sensing materials. Polymer-coated CuPd nanoparticles were synthesized by chemical reduction method, and B2 phase in CuPd alloy nanoparticles is effectively formed by the hydrogenation treatment.
10.1016-j.mseb.2014.02.001	1	shape; memory; shape memory; damping; martensite; martensitic; damping capacity; transformation; capacity; strain; superelasticity; temperature; cu-al-mn; shape memory effect; effect	The microstructure, martensitic transformation, mechanical and shape memory properties of Cu84-xAl11+xFe5 (x=0, 1, 2) alloys under the quenched and aged states were investigated. The results show that x=0 and 1 under the quenched state exhibit a mixture of primary beta'(1) and little gamma'(1) martensites, and x=2 only shows dominant gamma'(1) martensite. Small amounts of alpha(Cu) and Fe(Al,Cu) phases are observed for x=0, whereas only tiny Fe(Al,Cu) phase exists for x=1. After aging, all alloys have a mixture of beta'(1) and gamma'(1) martensites, and the snowflake-shaped gamma(1) (Cu9Al4) precipitate is present for x=2. The recovery strain and ratio for x=0 and 2 remarkably decrease after aging due to the precipitations. However, the recovery strain of x=1 after aging still linearly increases with the increase of the pre-strain, up to a maximum value of 1.6%.
10.1016-j.mseb.2018.11.027	1	shape; memory; shape memory; damping; martensite; martensitic; damping capacity; transformation; capacity; strain; superelasticity; temperature; cu-al-mn; shape memory effect; effect	In this study, the microstructure, martensitic transformation, superelasticity, stabilization of stress-induce martensite and the corresponding shape memory effect of Ti-doped Cu-Al-Mn shape memory alloys were investigated. The results show that the present Cu-Al-Mn-Ti alloys consist of two types of L2(1) phases, including Cu2AlMn parent and Cu2TiAl precipitate. The dispersive L2(1)-Cu2TiAl precipitates strengthen the stabilization of stress-induced 2H(gamma'(1)) martensite from L2(1)-Cu2AlMn parent. Thus, all studied alloys show not only superelasticity at deformation, but also shape memory effect after unloading by heating. Consequently, the Cu-12.9Al-8.3Mn-0.5Ti alloy (wt%) possesses the best superelastic strain up to 4.6% and a shape memory effect of 1.5% under a pre-deformation of 11%, while Cu-12.8Al-7.7Mn-2.6Ti alloy (wt%) shows the best shape memory effect up to 2,5% simultaneously showing 1.9% of superelastic strain with a pre-deformation of 10%.
10.1016-j.mseb.2020.114643	-1		Cu-Ni alloys have extensive applications in automobile, aerospace and marine industries due to their admirable physical, mechanical and chemical properties. However, further enhancement in the properties of Cu-Ni alloys through the incorporation of nanoparticles can promote their utilization in industrial applications. In this research, graphene nanoplatelets (GNPs) reinforced Cu-Ni alloy matrix composites were synthesized through a modified electrochemical-co-deposition method followed by convectional powder metallurgy method. Uniform dispersion of pristine GNPs in the Cu-Ni alloy matrix without damaging its structure is observed. Mechanical properties and tribological behaviour of Cu-Ni/GNPs composites were analysed. Vickers hardness, yield strength (YS), and ultimate tensile strength (UTS) of the sintered Cu-Ni/GNPs (200 mg/L) composite are 107 HV, 265 MPa and 299 MPa corresponding to an increment of 84.5%, 138.7% and 90.5%, respectively compared to that of pure Cu-Ni alloy. Cu-Ni/GNPs composites exhibited reduced friction coefficients and wear rates, associated with microstructural refinement and GNPs content. The results suggest that the combination of a modified electrochemical-co-deposition and powder metallurgy methods delivers a novel approach for facile synthesis of Cu-Ni/GNPs composite with excellent mechanical and tribological properties.
10.1016-j.mseb.2020.115010	-1		Nanoparticles have been widely used to tune the mechanical, thermophysical, and chemical properties of materials for widespread applications(1-3). Despite achieving other unprecedented functionalities, metals containing ceramic nanoparticles often suffer a significant loss in thermal conductivity with theoretical upper limits set by the Hashin-Shtrikman (with interfacial interactions) and Weiner (without interfacial interactions) models. Here, we discover that the Cu-60Ag alloy with 10 vol% WC nanoparticles delivers a surprisingly high thermal conductivity, breaking the theoretical upper limits. To understand the underlying mechanisms, thermal transport contributions from phonons and electrons, as well as microstructure, are studied. The study suggests that there exists an unusual enhancement of thermal transport in Cu-60Ag by the less conductive WC nanoparticles. Though thermal analysis including 3 omega-method may be needed to decouple influencing factors, this new finding is of significance for development and application of nanoparticles reinforced metals with both superior mechanical strength and high thermal conductivity.
10.1016-j.mseb.2024.117301	-1		This study focused on investigating the electrical and antioxidation properties of 20 mil Cu and Cu-Zn-Si microalloyed wire (CZS). The results revealed Cu wire exhibits fine-grained structure and annealed twins, while CZS wire containing trace amount of Zn and Si, primarily consist of equiaxed grains. Mechanical properties and hardness of CZS wire surpass those of Cu wire, indicating solid solution strengthening effect is achieved through the incorporation of micro-alloying process. Oxidation experiments indicated oxide layer of Cu wire affects the electrical properties and reduces the reliability. Silicon preferentially formed SiO2 and CuSiO3 phases, effectively retarding the rate of CuO formation. The results of electrical fatigue method indicated Cu wire is affected by CuO layer and significantly deteriorates electrical properties and current fatigue life. In contrast, CZS wire with a hypoeutectoid oxide layer has excellent electrical fatigue life and demonstrates the excellent electrical and thermal resistance of the CZS wire.
10.1016-j.msec.2006.08.032	-1		The precipitation behavior of dilute Cu-Co alloys under isothermal annealing has been investigated by means of transmission electron microscopy. The observations show that different mechanisms occur in the coherent and incoherent precipitation stages. Coherent homogeneous Co particles of about 15 nm in size are consistently observed from the early stages of precipitation. The coexistence of coherent nanoscale spherical precipitates together with incoherent microscale precipitates is observed at higher temperatures, above 600 degrees C, with the latter forming well-developed and faceted Co-rich crystals. In the heterogeneous decomposition mode, the development of discontinuous precipitation colonies consisting of regularly-spaced rod-like Co particles is observed. Upon further growth, these rods break down into chains of spherical particles which are thought to be formed as a consequence of Rayleigh instability. In addition, depending on the thermal conditions, the generation of domains on the order of 100 nm is observed within the matrix, which is constituted of large grains with average size of 100 gm. (C) 2006 Published by Elsevier B.V.
10.1016-j.mssp.2019.05.027	-1		Sequential layering of Zn and Sn on Cu foil by electrolysis of appropriate salt solution is carried out. The layered metals are annealed at 350 degrees C to form Cu-Zn-Sn alloy. To the alloy, 30 g of (excess) elemental sulphur powder is added and sulphurized at 350 degrees, 450 degrees, 550 degrees and 650 degrees C. Structural, morphological, optical and electrochemical investigations revealed CZTS as favourable phase at all sulphurization temperatures. Electrochemical Impedance studies in conjunction with Raman spectroscopy indicated negligible secondary phases for CZTS-550 degrees C when compared to CZTS synthesized at other temperatures. For CZTS-550 degrees C, UV-vis DRS studies depicted 1.51 eV as band gap and high absorption coefficient of 10(5) cm(-1). Thus CZTS synthesized by the demonstrated procedure can be suitable for optoelectronic applications.
10.1016-j.mtadv.2021.100141	3	sma; shape; shape memory; memory; smas; superelastic; bars; damping; cu-al-mn; mechanical; bending; applications; numerical; sma bars; material	Shape memory alloy undergoing reversible martensitic transformation is an important class of metallic functional materials. In the past two decades, the development of shape memory alloys enables great advances in biomedical devices, microelectronics, and energy conversions. As the application scales of these devices get smaller and smaller, it is very critical to understand and tune the mechanical properties of shape memory alloys in nanoscale regime. While there are extensive reviews of shape memory alloys regarding their macroscopic properties, metallurgical treatments, and applications in the design of microdevices, their nanomechanics are not well summarized and thoroughly compared transversely among different experimental setups. This review provides an insight of the latest discoveries in nanomechanics of NiTi-based and Cu-based shape memory alloys, which sorts out the size effects, the deformation mechanisms, and the functional fatigue of the miniaturized samples in single-crystalline and polycrystalline formats. (c) 2021 The Author(s). Published by Elsevier Ltd. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/).
10.1016-j.mtadv.2025.100604	-1		This study systematically reveals the influence of the crystal orientation and operating temperature on the superelasticity and elastocaloric effect of single-crystal Cu-Al-Mn-(Ni, Mo, Cr) shape memory alloys. These single crystals were prepared using the abnormal grain growth method to produce samples having orientations classified as approximately [0 0 1]beta, [1 0 1]beta, and [1 1 1]beta. The experimental results indicated that significant differences in energy dissipation and elastocaloric cooling capacity among the three types of orientations, which were attributed to the different numbers of induced martensitic variants and the magnitude of transformation fraction. Compared with the approximately [0 0 1]beta and [1 1 1]beta orientations, the approximately [1 0 1]beta orientation was considered the preferred choice for a solid-state refrigerant due to its smaller energy dissipation and the pronounced coefficient of performance of the material. On the other hand, the superelastic and elastocaloric properties of the three types of orientations changed as the testing temperature increased, which was attributed to atomic ordering (from 80 degrees C to 140 degrees C) and the formation of bainitic alpha (above 140 degrees C). This study identified the preferred orientation for solid-state refrigerant applications and comprehensively analyzed the influence of the operating environment on Cu-Al-Mn-(Ni, Mo, Cr) shape memory alloys for solid-state refrigeration.
10.1016-j.mtadv.2025.100622	14	strength; properties; conductivity; electrical; mechanical; cu-; grain; mpa; electrical conductivity; aging; precipitation; phase; mechanical properties; tensile; phases	Copper-iron (Cu-Fe) immiscible alloys are known for their potential to form hierarchical microstructures with superior mechanical properties under rapid solidification conditions. However, the formation of these microstructures during Cu/Fe melting and mixing-typically occurring in processes such as arc-and laser-induced melting-remains poorly understood, despite its relevance to the integration of structural materials across various industries. This study showed that hierarchical and homogeneous microstructures in Cu-Fe alloys can be tailored in situ with two distinct regimes governed by the degree of Fe dilution through non-equilibrium solidification. In the high-Fe content sample, phase separation during the liquid state, followed by Marangonidriven motion, led to the formation of a hierarchical structure comprising DO3-ordered Fe-rich particles with embedded Cu-rich grains, along with uniformly distributed γ′ nanoparticles. In contrast, the low-Fe sample exhibited more uniformly dispersed, smaller DO3-ordered Fe-rich particles with a lower number density, along with dispersed γ′ nanoprecipitates. The formation of such microstructures, including Cu/DO3 Fe-rich particles and γ′ nanoprecipitates, was primarily governed by surface energy-driven mechanisms and solute trapping under rapid cooling. These microstructures enhanced the local hardness and elastic modulus, primarily due to the increased number density of Fe-rich particles, highlighting their dominant role over size or morphology in strengthening Cu-Fe alloys. This study provides new insights into the microstructural evolution of immiscible alloy systems. The findings offer a foundation for microstructural tailoring to enhance mechanical performance and expand the potential applications of Cu-Fe alloy systems in advanced engineering technologies.
10.1016-j.mtcomm.2020.101153	16	wear; composite; composites; powders; milling; particles; powder; wt; sliding; friction; hardness; matrix; mechanical; surface; properties	This work aims to reveal the positive effects of silver coating and milling of copper particles on the physical properties such as density, hardness and electrical conductivity of Al2O3 reinforced copper matrix composites. Al2O3 particles reinforced (0.5, 1, 2, 3 and 5%wt.) silver coated and uncoated copper matrix composites were fabricated using the hot-pressing method. A scanning electron microscopy (SEM) was used to investigate the morphology of powders and microstructure of the silver coating layer and composite samples. The density (delta) and hardness of compacts was determined by the Archimede's method and Brinell hardness method, respectively. Electrical conductivity of samples was measured using Sigmascope SMP10 HF electrical conductivity measurement device and reported in the International Annealed Copper Standard (IACS). The best coating homogeneity in copper-silver core-shells was observed in milled copper powders for 2 h . The density of samples decreased but the hardness of samples increased with increasing Al2O3 content due to hard and non conductive structure of Al2O3 ceramic particles. The highest hardness was measured as 125 HB for silver coated copper matrix composites fabricated by using 2 h of milling and 3%wt. Al2O3 content. 95 HB was obtained for the uncoated copper matrix composites fabricated by using 3 h of milling and 3%wt. Al2O3 content. For composite samples, the highest electrical conductivity value was measured as 88%IACS for silver coated copper matrix composites synthesized by 2 h of milling and 3%wt. Al2O3 content.
10.1016-j.mtcomm.2020.101321	4	transformation; martensite; martensitic; phase; shape; beta; memory; shape memory; temperature; temperatures; martensitic transformation; gamma; transformation temperatures; effect; thermal	Cu-based shape memory alloys have shown great potential for seismic applications, due to their excellent superelasticity and damping capacity. Understanding energy dissipation from the phase transformation is key to improving the performance of these alloys. In this work, we apply the data-driven identification method (DDI) combined with digital image correlation measurements to study the local energy dissipation characteristics of a Cu-Al-Mn single-crystal alloy. We find that the superelasticity behavior, e.g., the overall mechanical response of the shape memory alloys, can be captured by the DDI method. The measured stress and strain fields help to reveal martensite phase transformation zones and energy dissipation features. We find that the dissipated energy occurs mainly in the interfacial region of the martensite to austenite transformation. Energy is dissipated at the pathway of the moving interfaces during the associated forward/reverse martensitic transformation. The local specific dissipation energy in martensitic bands can be twice the average value of the bulk materials.
10.1016-j.mtcomm.2020.101353	15	aging; strength; conductivity; electrical conductivity; electrical; mpa; treatment; strengthening; degrees; cu-; cold; precipitation; tensile strength; tensile; iacs	The tradeoff between the strength and fracture elongation in the high strength Cu-Fe alloys has been a research focus recently. A Cu-10 wt%Fe-0.5 wt% Nb alloy was designed and fabricated by casting and thermomechanical treatment to high strength and elongation. Microstructure evolutions and properties variations of the studied alloy during cold-drawing and cold rolling were investigated. After annealed at 400 degrees C for 1 h and further aged at 450 degrees C for 8 h, the ultimate tensile strength, elongation, product of the strength times the elongation (PSE), and electrical conductivity of the cold-drawn studied alloy were 736 MPa, 36 %, 22.82 GPa (center dot)%, and 48.74 %IACS, respectively. Nanocrystals, Nb precipitates, and Fe fibers were detected in the studied alloy, which contributed to the high strength and the high fracture elongation. These findings provide essential understandings of the effects of the niobium on Cu-Fe system alloys, and the designed Cu-Fe-Nb alloy with high strength and fracture elongation could fulfill some requirements of the electronic and electrical industry.
10.1016-j.mtcomm.2020.101746	6	grain; deformation; strain; strength; dislocation; cu-; tensile; size; ecap; grain size; sfe; ductility; hardening; high; stress	A commercially pure Cu and a Cu-8 wt%Sn alloy were subjected to high pressure torsion (HPT) to study the effect of Sn as solute element and deformation rate on the grain refinement mechanism and the defect accumulation in Cu. The microstructure and hardness of produced ultrafine grained (UFG) states of both materials were carefully characterized. We show that addition of Sn in Cu leads to significant decrease in grain size, accumulation of higher stored energy and increase in hardness accompanied with the delay of hardness saturation with shear strain. Increasing HPT deformation rate induces significant heat dissipation in the processed materials markedly pronounced in CuSn8 as compared to Cu. Surprisingly, deformation rate has the opposite effect on the microhardness of UFG Cu and CuSn8, which decreases with the deformation rate for the case of Cu, while exhibits faster saturation to higher values for CuSn8. We also show that despite higher self-heating at higher deformation rates, higher HPT rotation speed provides reduction in grain size and increase in the defect density for CuSn8 alloy. This effect is assumed to be related to strong interactions between Sn solute atoms and strain-induced defects so that mechanically driven effects prevail over dynamic annihilation of dislocations. Finally, we present a qualitative model based on the phenomena of production and annihilation of dislocations. This model was able to reproduce the evolution of grain size, concentrations defects and hardness with different deformation parameters and after the addition of solute element in material.
10.1016-j.mtcomm.2020.101963	-1		Nanocrystalline Cu-Zr alloys are an emerging class of immiscible high-strength materials with significant potential for structural and high-temperature applications. The effects of Zr concentration and tensile velocity on the strengthening and mechanics of Cu alloyed with Zr is studied using molecular dynamics simulations based on the many-body embedded-atom potential. The simulation results show that the potential energy of Cu-Zr systems significantly decreases with increasing Zr concentration, resulting in an increase in structural stabilization. Doping Zr atoms at the grain boundaries can strengthen the boundaries and reduce their mobility during the tensile test. The Young's modulus of Cu-Zr systems decreases with increasing Zr concentration. The plasticity of Cu-Zr systems increases with increasing Zr concentration. The mechanical strength of Cu-Zr systems reaches its maximum value, which is 1.13 times that of the pure Cu counterpart, when the Zr concentration is 5%.
10.1016-j.mtcomm.2021.102266	15	aging; strength; conductivity; electrical conductivity; electrical; mpa; treatment; strengthening; degrees; cu-; cold; precipitation; tensile strength; tensile; iacs	In this study, microstructures, mechanical properties, and electrical conductivities of powder metallurgy (PM) Cu-0.28Cr-0.19 Mg alloy after cold-rolling and aging were investigated in detail. PM Cu-Cr-Mg alloy exhibits a combination of both higher mechanical properties and superior electrical conductivity compared to the corresponding casting Cu-Cr-X alloys. Such excellent performances are closely related to the more uniform and finer microstructures generated in PM process. Strengthening from second phase precipitation, grain boundary, and dislocation in the present PM Cu-Cr-Mg alloy were calculated to be approximately 43.65, 24.50, and 23.12 % of yield strength, respectively. The grain boundary strengthening is the main reason for the higher strength of the present PM Cu-Cr-Mg alloy and is approximately 325 % higher than that of the corresponding casting Cu-Cr-Mg alloy. The gradually decreased activation energy of PM Cu-Cr-Mg alloy with increasing reduction rate suggests that deformation significantly accelerates the precipitation behavior during the subsequent aging process.
10.1016-j.mtcomm.2021.102378	-1		In this work, the influence of different Ti additions on microstructure and property in Cu-Cr alloys has been studied and the primary relationship of processing-microstructure-property in Cu-Cr-Ti alloy has been constructed via the CALPHAD-based Integrated Computational Materials Engineering (ICME) approach and experimental validation. The peak-aged Cu-0.5Cr-0.2Ti alloy offers an excellent combination of hardness 192.6 HV, tensile strength 629.3 MPa, yield strength 603.0 MPa, electrical conductivity 51.3 %IACS and elongation 10.9 %. The calculated results suggest that the addition of Ti could promote the nucleation and hinder the growth of Cr precipitate in Cu-Cr-Ti alloys during aging treatment, which may promote the homogeneous formation of smallsize precipitate Cr and improve the strength of the Cu-Cr alloy. Microstructural characterization has validated the calculation results and revealed that the exceptional properties of this alloy are mainly attributed to nano-scale Cr precipitates achieved through the optimal thermomechanical processing from present ICME. Thus, the present ICME flowchart is applicable to design alloy composition and optimize the processing for the desired microstructure and property in engineering industries.
10.1016-j.mtcomm.2021.102409	-1		In this work, novel Cu-Ga-In alloys are designed with systematic variation in the liquid and solid solution phases to mimic the nature-inspired structures and their properties. A combination of characterization techniques such as X-ray Diffraction (XRD), Optical microscopy, scanning electron microscopy (SEM) and 3D X-ray tomography along with thermodynamic calculations confirm the presence of liquid and solid solution phases in the micro-structure. The effect of the liquid phase in increasing the ductility and toughness is clearly demonstrated in the present study. It is shown that the liquid phase can arrest the crack movement during the fracture that leads to improved toughness in the Cu-Ga-In based alloys. Moreover, the presence of the liquid phase also improves the wear properties of these alloys. The present alloys exhibited better hardness and reasonable yield strength compared to the existing Cu alloys in the literature. Especially Cu65In20Ga15 alloy exhibits the hardness of 660HV and the yield strength of 335.49 MPa which is higher than conventional copper alloys.
10.1016-j.mtcomm.2021.102436	-1		Solid state alloying of immiscible alloy systems such as Cu-Cr is an important field of physical metallurgy. Currently, non-equilibrium techniques are successfully applied in the synthesis of Cu-Cr alloys; however, the mechanism of formation of these alloys remains unclear due to the unavailability of data regarding their microstructure evolution and thermodynamic characteristics. In this work, a mechanical alloying (MA) Cu-60wt%Cr alloy is prepared by high-energy milling. The phase transitions, thermodynamic properties, and microstructure of this alloy are analyzed using X-ray diffraction, differential scanning calorimetry, and transmission electron microscope techniques. The obtained results demonstrate that the supersaturated Cr(Cu) solid solution alloy has a supra-nanometer-sized microstructure and is composed of crystalline and amorphous phases. To form the alloy, the localized Cu is first transformed into an amorphous state, then the disordered Cu atoms diffuse into the Cr matrix during the MA process. The diffusivity of Cr atoms in the Cu lattice is significantly hindered, even when the lattice is heavily defected.
10.1016-j.mtcomm.2021.102676	-1		Effects of different processes including various combinations of equal channel angular pressing (ECAP) and aging on the microstructure, mechanical and tribological properties of the quadruple Cu-Co-Ni-Be alloy were investigated. ECAP process results in a significant grain refinement and brings about an ultrafine-grained (UFG) microstructure. Grain boundary strengthening and strain hardening mechanisms increase the strength and hardness of the ECAPed alloy significantly. Subsequent aging of the ECAPed sample results in a further increment in the hardness and strength due to the formation of precipitates besides the UFG structure. Wear resistance and operative wear mechanisms of the alloy depend on the applied processes strongly. ECAPed + aged sample with the highest hardness exhibit the highest wear resistance among all samples. Detailed investigations show that various wear mechanisms are operative in the Cu-Co-Ni-Be alloy samples. Adhesive wear is the mean wear mechanism in the initial and aged samples, and it is more prominent in the initial sample than the aged one due to the its quite softer and more ductile nature. Limited abrasive wear is also operative in these samples. delamination wear, on the other hand, is observed to be the main wear mechanism in the ECAPed and ECAPed + aged samples. Wear particles generated due to the delamination process cause three-body abrasive wear as an another wear mechanism in the UFG samples. Besides, oxidative wear is also operative in these samples and it is more prominent than that of the initial and aged ones. The achieved results show that UFG formation by any manner and subsequent aging processes are effective to improve wear resistance of the Cu-Co-Ni-Be alloys.
10.1016-j.mtcomm.2021.102693	-1		This work presents a study based on numerical simulations to describe the local structural evolution of Cu-Zr-Al amorphous alloys when moderate stresses are applied and removed. In particular, it will seek to recognize the formation of clusters with some degree of symmetry in the amorphous matrix and how these are altered depending on the mechanical stress experienced by them. The selected technique is classical molecular dynamics, using the 'Embedded-atom method' (EAM) and some other studies trying to identify local crystalline order (Common Neighbor Analysis, atomic centro-symmetry parameter, radial distribution functions and the recip-rocal space pattern). The simulations confirm the local order/disorder mechanism based on the existence of ordered regions, which depends on the nature of the applied stress. Particularly, this work focused on performing simulations in time and stress regimes close to anelastic experimental conditions, which makes it different to other related computational reports that focus on regimes close to plastic deformation. The atomistic simulations provide strong evidence of the local ordering occurrence, in good concordance with early ultrasound assisted experiments on Cu-Zr-Al amorphous alloys, thus providing strong evidence of the local ordering occurrence in an elastic regime when uniaxial stress is applied. The reversibility of the system, when stress is removed, was also shown. The application of uniaxial stress favors the presence of different kind of local order structures, when compared with the situation of hydrostatic pressure.
10.1016-j.mtcomm.2021.102826	2	corrosion; surface; film; electrochemical; films; spectroscopy; layer; current; solution; potential; resistance; composition; x-ray; ions; showed	Benzotriazole (BTA) and tolyltriazole (TTA) were used to passivate pure copper and chromium bronze alloys for environmental protection. Using the chemical immersion treatment, a dense film of chromium-free passivation layer was formed on surfaces of both the pure copper and chromium bronze alloys. Microstructure, crystalline phases and chemical bonds of the passivation layers were systematically characterized, and the passivation mechanisms were studied. The passivation layer was mainly consisted of CuO, Cu2O, polymers of Cu-BTA-TTA and Cu(I)BTA-TTA. The formation mechanism of the chromium-free passivation layer was identified as combined oxidation and adsorption, and the main passivation processes included oxidation and dissolution of the matrix, adsorption of BTA and its derivatives, self-stabilization process of the adsorbed film, and filling of passivation film's voids by oxide particles.
10.1016-j.mtcomm.2021.102856	6	grain; deformation; strain; strength; dislocation; cu-; tensile; size; ecap; grain size; sfe; ductility; hardening; high; stress	The deformation mechanism of bimodal nanotwinned (NT) Cu-Ag alloys with grain boundary affect zone (GBAZ) segregation has been investigated through molecular dynamics (MD) simulations. The bimodal NT Cu-Ag alloys model is established by embedding a coarse NT grain into the ultrafine grained matrix. The solute Ag atoms in Cu-Ag alloy polycrystalline matrix are segregated in the GBAZ (generated by equidistance scaling method). The coarse NT grain inclusion phase can impart high strength resulting from the twin boundaries (TB) strengthening regime. Through the uniaxial tensile simulations, the strength of bimodal NT samples is found to be related with the three factors, including coarse NT grain size, TB inclination angles as well as TB spacings (TBSs). The dislocation activities and corresponding deformation mechanisms are explored in detail.
10.1016-j.mtcomm.2021.103037	-1		Carbon steel and Cu-Pb-Sn bimetallic samples were prepared by the solid-liquid composite method. The preheating temperature of the steel matrix was 1150 +/- 30 degrees C and the Cu-Pb-Sn alloy smelting temperature was 1200 +/- 20 degrees C. The Cu-Pb-Sn alloy was subsequently poured into the preheated steel matrix to form a bimetallic composite interface. The influence of phosphorus (P) on the microstructure and mechanical properties of the interface and the behavior mechanism of P at the bimetallic interface were examined. The results showed that when the P content was 0.1% (all contents reported herein are in wt%), the carbon steel and Cu-Pb-Sn alloy formed an ideal metallurgical bonding interface. It was found that a nanoscale Fe3P phase was precipitated at 750 degrees C at the grain boundary of the alpha-Cu interface. The Fe3P interplanar spacing of the phase was 2.1 angstrom, and the interplanar spacing of alpha-Cu was 2.07 angstrom. When the P content reached 0.2%, the Fe3P phase precipitated at 1020 degrees C and aggregated into micrometer size at the interface, which formed a transition zone with alpha-Cu. The transition zone widened with an increase in the P content in the alloy liquid. The interface atomic diffusion distance between Fe and Cu was 11.55 mu m when the P content was 0.1%, and the sample shear strength reached a maximum value of 157.89 MPa. With increasing P content, the interface became hard and brittle because it emerged in the precipitated transition zone, which decreased the shear strength .
10.1016-j.mtcomm.2022.103138	-1		Establishing the property contour-map using the classical physics-based models is easy to fall into the dimension disaster due to the complexity of experimental variables (composition and heat treatment), limiting the discovery of alloys with high hardness and good electrical conductivity (EC). Here, we propose the combination of a Gaussian process regression-based machine learning (ML) surrogate model and the phase diagram to search for compositions with better target properties in Cu-Co-Si alloys. The ML models trained from discarded experimental data with undesirable hardness or EC establish the connection between input variables (experimental variables and other features) and target properties. After five iteration loops, the highest EC and hardness of the alloys were optimized to 69.24% IACS and 207.39 HV, 20.8% and 14.7% higher than the best values in the initial training data. The optimum compositions of Cu-Co-Si alloys are discovered from the contour maps which consist of the properties of 12,000 alloys predicted by our ML models. Combined with the phase diagram and microstructure characterization, we infer that the moderate precipitation of Co2Si leads to high conductivity and the precipitation of Co2Si and CoSi strengthens the Cu matrix.
10.1016-j.mtcomm.2022.103222	13	clusters; atomic; glass; atoms; composition; dynamics; metallic; icosahedral; glasses; simulations; molecular; cu-zr; molecular dynamics; metallic glasses; structural	Bimetallic CumPdn nanoalloy clusters of small size (m+n <= 12) are systematically studied using the spin polarized density functional theory to understand the evolution of structural, mixing, electronic and magnetic properties with size and composition of the binary system. The lowest-energy configurations of the series of bimetallic clusters are determined from unbiased global search with genetic algorithm. With the increase of size, Cu-Pd clusters tend to adopt compact geometries. For a given cluster size, Pd atom prefers the outer position, while Cu atom favors the inner site. Stability analysis reveals that nanoalloy formation for CumPdn clusters is favored for the overall range of sizes and compositions. The small changes in structures of magic clusters with their neighboring compositions indicate that their high stability is primarily due to the variation in composition, not to the change in structure. The electronic state of the Pd atom is promoted upon the formation of the Cu-Pd nanoalloy clusters, while that of the Cu atom remains almost unchanged. The magnetic moments of CumPdn clusters exhibit an evident oscillation behavior with the composition, which can be attributed to the substantial hybridization between the electronic states of Pd and Cu.
10.1016-j.mtcomm.2022.103399	-1		CuAl alloy is an important host material for abradable sealing coatings, and its aluminum content has a significant effect on the performance of the coatings. In this article, the mechanical properties of Cu-Al binary alloys at finite temperatures were investigated using the first-principles calculation based on density functional theory. Cu-Al disordered alloys were modeled using the special quasi-random structure. The Al content of the alloys were 0 at%, 3.125 at%, 6.250 at%, 9.375 at%, 12.500 at%, 15.625 at% and 18.750 at%, respectively. Their mechanical properties at 0 K, 300 K and 870 K were investigated in combination with quasi-harmonic approximation. The results showed that the mechanical stability, shear modulus, Young's modulus, and bulk modulus of the alloy performed a decreasing trend with increasing Al content at 0 K. With the increase of temperature, all the above properties showed a decreasing trend. The shear modulus, Young's modulus and bulk modulus of the alloy with 18.750 at% Al content at 870 K decreased by 21.2%, 21.4% and 23.0%, respectively, compared with those at 0 K. With the increase of Al content, B/G ratio first decreased and then increased. The experimental results showed that the trend of those mechanical properties with Al content was consistent with the calculated results. The secondary phase appeared when the Al content is 18.850 at% in the experiment, which made an inflection point in the trend of the alloy properties. Considering the abradability and erosion resistance of the sealing coating, the Al content in the range of 15.625-18.750 at% with single alpha phase is more suitable for practical applications.
10.1016-j.mtcomm.2022.103473	6	grain; deformation; strain; strength; dislocation; cu-; tensile; size; ecap; grain size; sfe; ductility; hardening; high; stress	The effect of the precipitation hardening by means of the conventional heat treatment and the combined thermomechanical treatment (i.e., equal channel angular pressing (ECAP) with subsequent aging) on the electrical conductivity, mechanical properties and precipitation kinetics of precipitation hardening, quadruple CuCo1Ni1Be alloy was investigated. No experimental studies on the effect of ECAP on the electrical conductivity and precipitation kinetics of CuCoNiBe alloys have been reported. Systematic microstructural and mechanical investigations show that both ECAP processing and post-ECAP aging result in a significant increase in the hardness and strength of the alloy due to the grain boundary strengthening by means of the grain refinement (and the formation of subgrains) and due to the precipitation hardening by means of the formed precipitates (primary and secondary beryllides) in the fine-grained structure, respectively. Moreover, the electrical conductivity of both solution treated and ECAPed alloys increases with increasing aging time due to the precipitation of the solute atoms in alpha-Cu matrix leading to decreasing electrical resistivity. However, the CuCo1Ni1Be alloys subjected to ECAP exhibit a lower conductivity than the solution treated ones, which can be attributed to an increase in resistivity caused by increased probability of electrons scattering by severe plastic deformation. The linear relationship between electrical conductivity and volume fraction of the precipitates according to the Martition's law and the empirical Avrami equation are used to investigate the precipitation kinetics of the CuCo1Ni1Be alloy. The S-shaped volume fraction of precipitates vs. aging time curves clearly indicate that the precipitation kinetics of the CuCoNiBe alloys can be significantly promoted by ECAP processing. The results of the present study provide new insights into the interaction of the severe plastic deformation, the kinetics of precipitation, and the microstructural, mechanical and physical properties of the CuCo1Ni1Be alloy.
10.1016-j.mtcomm.2022.103523	-1		In nano-machining, some alloys exhibit crystalline plastic deformation properties, while others exhibit amorphous deformation properties. However, the conversion mechanism between crystalline and amorphous properties is still unclear. In this paper, molecular dynamics (MD) simulation methods were employed to study the plastic deformation transformation mechanism between crystalline and amorphous during nano-machining of Cu-Al alloys. The simulation results show that Cu-Al alloys with different element ratios will complete amorphization as long as the proportion of FCC crystal structure in the alloy is less than 86%. Meanwhile, the material removal rate, ploughing width, and cutting force change significantly during the amorphization process. The lower the potential energy of the atoms inside the Cu-Al alloy, the higher the temperature required for amorphization. This work can enrich the understanding of the material removal mechanism of alloy material.
10.1016-j.mtcomm.2022.103586	6	grain; deformation; strain; strength; dislocation; cu-; tensile; size; ecap; grain size; sfe; ductility; hardening; high; stress	The nanoscale microstructures of metals and alloys are well recognized to influence their strength and plastic deformability. In order to understand specifically the mechanism by which twinning in the ultrafine grain region affects the mechanical properties of bimodal Cu-Ag alloys, we investigate the deformation of bimodal twinned Cu-Ag alloys under uniaxial stretching by molecular dynamics (MD) simulations. The experimental simulations reveal that the coarse grain size and Ag atom volume fraction have important effects on the mechanical behavior of the bimodal nanotwinned Cu-Ag alloy. Ultrafine nanotwinned grains are endowed with high strength due to the twinning boundary strengthening effect. More HCP structures are generated with more capacity to store some of the dislocations in the coarse crystalline region, thus contributing to the ductility of the bimodal twinned CuAg alloy. The dependence of stress on coarse grain size and Ag atom volume fraction is discussed in detail in this paper.
10.1016-j.mtcomm.2022.103771	-1		The Cu-1Ni-0.9Sn-0.5Ti-0.3Cr alloy was prepared by vacuum induction melting. The hot deformation experiments with the alloy were carried out using the Gleeble-1500 deformation simulation device at 0.001-10 s -1 strain rate, and 500-900 degrees C deformation temperature. The hot working constitutive equation for the Cu-1Ni0.9Sn-0.5Ti-0.3Cr alloy was established. The optimal hot processing of the Cu-1Ni-0.9Sn-0.5Ti-0.3Cr alloy is at 725-900 degrees C and 0.01-0.223 s(-1) strain rate, so the alloy can obtain the required defect-free structure and excellent machinability. The alloy microstructure was analyzed using the electron backscatter diffraction, and the main texture of the Cu-1Ni-0.9Sn-0.5Ti-0.3Cr alloy deformed at 800 degrees C is the {011}< 100 > Goss texture, which is replaced by the {011}< 211 > brass texture at 900 degrees C. Recrystallization is promoted by higher deformation temperature. The recrystallization process provides energy for recrystallization by consuming dislocations, and the geometrically necessary dislocation density decreases with temperature. Transmission electron microscopy of the alloy shows that the precipitates are mainly Cu and NiTi phases. The interface between the two precipitated phases is semi-coherent. The precipitated phase at a semi-coherent interface can produce smaller elastic stress and lower interfacial energy, thus improving the refinement rate. Meanwhile, the Cu and NiTi phases have high toughness, and grain refinement can effectively improve the strength and hardness of the alloy.
10.1016-j.mtcomm.2022.104134	-1		A Cu-5 wt% Mo alloy with high conductivity and high anti-soften temperature were fabricated by combining mechanical alloying with spark plasma sintering (SPS). Cu-5 wt% Mo mixed powders with four kinds of ball milling parameters were prepared by mechanical alloying. The sintered Cu-5 wt% Mo alloy was rolled and aged. The rolled Cu-5 wt% Mo alloy achieved a relative density of 98.19%, an electrical conductivity of 92.6%IACS, a microhardness of 128.6 HV, an ultimate tensile true stress of 441.2 MPa, and an elongation of 24.9%. Nanoscale Mo precipitates were formed during aging process. The aged Cu-5 wt% Mo alloy reached an electrical con-ductivity of 96.5%IACS and an anti-soften temperature of 950 degrees C. These findings are instructive for the devel-opment of copper alloy materials with high conductivity and high anti-soften temperature.
10.1016-j.mtcomm.2022.104286	5	materials; thermal; heat; properties; material; welding; sintering; fusion; strength; laser; heat sink; thermal conductivity; mechanical; sink; manufacturing	Cu-Ge system was evaluated for its application as a filler material in W-CuCrZr joints proposed as heat sink components of the future fusion power plants. The selected compositions were rich in Cu, with the aim of retaining the ductility that characterizes copper metal. Three compositions (Cu-13.5Ge, Cu-19.5Ge and Cu-33.2Ge) and two manufacturing routes (flexible and rigid tapes) were evaluated and characterized thermally, microstructurally and mechanically. The brazing temperature decreased as the Ge content increased, giving rise to less base material thermal affectation. The microstructure was dominated by several peritectic reactions that hinder the solid state diffusion control, and three main phases (Cu solid solution, epsilon and zeta) were detected both in the solidified filler drop and in the joint braze. In addition, the rigid filler manufacturing route seemed to produce more continuous joints due to its more homogeneous composition. The mechanical properties indicated that both lower and richer Ge compositions gave rise to joints with higher strength .
10.1016-j.mtcomm.2022.104300	0	solidification; phase; magnetic; magnetic field; undercooling; field; liquid; separation; peritectic; immiscible; cu-; dendrite; phase separation; microstructure; primary	In this article, the influences of cooling rate on the microstructure evolution and liquid-liquid phase separation behavior of Cu-16.2Fe-4.5 P immiscible alloys were systematically investigated. With the cooling rate changing from 1580 K/s to 30 K/s, Cu-16.2Fe-4.5 P metallic samples were still composed of Cu, Fe2P, Fe3P and Cu3P phases according to XRD analyses. With the cooling rate as 1580 K/s, it was observed that Fe-P particles as secondary phase exhibited nearly spherical shape with a uniform dispersion in Cu-rich matrix, which was attributed to the suppressed Marangoni convection and Stokes motion. As the cooling rate decreasing to 30 K/s, an evolving core-shell structure in this alloy was observed to be formed due to the relatively sufficient liquid separation occurrence. Furthermore, it was found that a Fe2P layer was formed to be encapsulated secondary phase, in which Fe3P and Cu particles were also examined. In addition, the microstructure evolution mechanism of Cu-16.2Fe-4.5 P alloys with different cooling rate was also applied.
10.1016-j.mtcomm.2022.104390	-1		A long-standing endeavor for materials scientists is to develop structural materials with a multitude of extreme properties. Toward this, nanocrystalline materials have enhanced mechanical strength and unique deformation mechanisms that provide potential for various structural applications. However, for the production of structural materials to be more viable, the scalability of nanocrystalline materials to bulk scale, utilizing industrially based practices that are reliable and stable, is as critical as some of the unique properties of such materials. The work presented here highlights an important step forward in the developmental process of nanocrystalline-based structural materials with a multitude of optimized properties and scalability for various engineering applica-tions. By utilizing common thermo-mechanical processing routes such as hot isostatic pressing (HIP) in combi-nation with open die forging on alloys that form extremely stable nanostructures, a single, fully dense 7.5 lbs (3.42 kg) ingot of nanocrystalline copper tantalum (Cu-Ta) was produced. Microstructural evolution during processing as well as the comparative mechanical response is reported. This work builds on the tremendous progress that has been made in the field of nanostructured materials in the last two decades to produce volumes of material that can be measured in centimeters and kilograms rather than microns and milligrams.
10.1016-j.mtcomm.2022.104418	7	irradiation; shear; grain; ta; deformation; size; radiation; voids; nanocrystalline; simulations; similar; void; temperature; irradiated; boundaries	Understanding the response of nanovoids to irradiation damage advances our capability to design radiation tolerant materials. Recent in situ studies reveal the shrinkage of hexagon-shaped nanovoids in (110) textured Cu. However, the evolution of voids with irregular geometries under irradiation is less well understood. Here, in situ Kr ion irradiation was performed at 100 degrees C on single-crystal Cu (112) that possesses nanovoids with high aspect ratio. In situ studies show these elongated voids fragment into smaller voids and shrink gradually with increasing dose. Phase field simulations confirm that fragmentation of the void is governed by the competing kinetics between atoms diffusing toward and away from the elongated nanovoid. Post irradiation analysis reveals the formation of high-density defect clusters.
10.1016-j.mtcomm.2022.104452	16	wear; composite; composites; powders; milling; particles; powder; wt; sliding; friction; hardness; matrix; mechanical; surface; properties	In the study, the effects of mechanical alloying (MA) time and Cr content (wt%) on the microstructure, density and hardness, electrical conductivity and oxidation resistance of Cu-Cr alloys were investigated. Cu-Cr alloy powders containing 0.25, 0.5, 1 and 2 wt%Cr powders were milled for 0.5, 1, 2, and 4 h in a planetary ball mill. Results showed that experimental density of pure copper sample was measured as 7.03 g/cm3. The highest density of 8.43 g/cm3 was achieved for the Cu-Cr alloys with 0.5 wt% Cr fabricated by 4 h of MA. The hardness of Cu-Cr alloys increased with increasing MA time and Cr content. The Cu-Cr sample containing 2 wt% Cr showed highest hardness value of-128 HB. Electrical conductivity of Cu-Cr alloys with 0.5 wt% Cr fabricated by alloying for 4 h reached to the optimum of 91 %IACS.
10.1016-j.mtcomm.2022.104819	15	aging; strength; conductivity; electrical conductivity; electrical; mpa; treatment; strengthening; degrees; cu-; cold; precipitation; tensile strength; tensile; iacs	Copper-based wire is the key conductor material in integrated circuit bonding wire, high-end audio and video transmission line, medical wire harness and other fields. It is of significant interests to improving the strength and retaining their good electrical conductivity of copper-based wires for broad applications. The combination of heat treatment and deformation to control the microstructure is a promising method for this objective. In this paper, the Cu-3.5 wt. %Ag alloy rod with diameter of 16 mm was prepared by the hot mold horizontal continuous casting. We discussed the effects of solution + aging (S.A), solution + aging + cold drawing (S.A.C), solution + cold drawing + aging (S.C.A) on the distribution of Ag phase, dislocation morphology, strength and electrical conductivity of Cu-3.5 wt. %Ag alloy. The results show that continuing cold deformation after aging makes the strength of Cu-3.5 wt. %Ag alloy is up to 417.2 MPa, which is 84.6 % higher than that by S.A process. After S.A.C treatment, the dislocation density sharply increases, and the dislocation is arranged in a network structure. The dispersed nano-spherical Ag phase with an average size of 12 nm precipitation after aging strongly prevents dislocation slip. Moreover, the chain-like Ag phase effectively intercepts or lock the dislocations in the local area. The S.A.C process fully exerts the synergistic strengthening effect of aging precipitation strengthening and deformation strengthening induced by the interaction between nano-Ag phase and dislocation. This process is suitable for medical wiring harness, bonding wire and other application scenarios with higher strength re-quirements. On the other hand, if cold deformation is applied before aging, that is, S.C.A process. The electrical conductivity of Cu-3.5 wt. % Ag alloy reaches 95.5 % IACS, which is close to 100 % IACS of pure copper. The achievement of ultra-high conductivity is mainly attributed to the formation of a large number of band-shaped nano-Ag phase with an average length of 450 nm and width of 25 nm, and the arrangement direction remain consistent. In addition, the uniform distribution of dislocations is also beneficial to greatly improve the electrical conductivity. The S.C.A process is suitable for high-end audio and video transmission lines and other application scenarios that require higher electrical conductivity.
10.1016-j.mtcomm.2022.105202	-1		The detailed structure of the boundary between the Cu matrix and precipitate formed during the aging process of the Cu-4 at% Ti alloy was analyzed using atom probe tomography. The precipitate formed during peak aging was an ordered alpha-Cu4Ti (D1a, MoNi4-type) phase, the central part of which had an order degree of one, with a composition of 20 at% Ti. However, the outer part was a thick diffuse boundary with a gradually decreasing order degree in the radial direction and a composition range of 5-20 at% Ti. To analyze the detailed structure of the diffuse boundary, we hypothesized that a molecule-like motif (MLMh, (Cu4Ti)nTi) is the basic structure of the D1a phase, that is, the tight aggregates of MLMh form the full ordered D1a phase. MLMh can be represented by a compositional formula similar to a molecule, be dispersed in a Cu matrix, and form a diffuse boundary which is the low ordered D1a phase. MLMh is generated during the quenching process of the solution treatment, grows through subsequent aging, and aggregates via Ostwald ripening. The Ti atoms in MLMh are attracted linearly by the Ti 4sp3 orbital with a conjugated structure, which induces tetragonal distortion (a/c<1) in the face-centered cubic sublattice in D1a. The Ti-Ti axial toughness MLMh provides slip resistance toward dislocations. Therefore, after aging for 5 min, the strength of the alloy increased to 64% of the incremental strength at peak aging. In the solution-treated state, conductive electrons transfer to the orbitals of MLMh dispersed in the Cu matrix, resulting in high electrical resistivity, but the electrical resistivity decreases due to phase separation via aging. MLMh explains in detail the growth process of the aging structure, the structure of the diffuse boundary, and the cause of its properties.
10.1016-j.mtcomm.2023.105394	15	aging; strength; conductivity; electrical conductivity; electrical; mpa; treatment; strengthening; degrees; cu-; cold; precipitation; tensile strength; tensile; iacs	The effects of trace Si element on the microstructure, mechanical properties and high temperature softening resistance of Cu-0.9Ni-1.9Sn-0.1 P (mass fraction, %) alloy were studied using hardness tests, conductivity measurements, SEM, TEM and XRD observations. According to the results, after 70% cold rolling and aging at 450 degrees C, the micro-hardness, conductivity and softening temperatures of Cu-0.9Ni-1.9Sn-0.1 P-0.1Si alloy were up to 224.2 HV, 36.4%IACS and 520 degrees C. In comparison with Cu-0.9Ni-1.9Sn-0.1 P alloy, the micro-hardness of Cu0.9Ni-1.9Sn-0.1 P-0.1Si alloy was increased from 192.3 HV to 224.2 HV, and the conductivity increased from 33.6%IACS to 36.4%IACS. TEM analysis shows that adding Si can from precipitated Ni2Si phase with Ni and increase the strength of Cu-0.9Ni-1.9Sn-0.1 P-0.1Si alloy. Moreover, the addition of 0.1% Si can increase the softening temperature of the Cu-0.9Ni-1.9Sn-0.1 P alloy. As a result of annealing at different temperatures, the softening mechanism of the alloy varies. When the annealing at low temperature ( 400 degrees C-480 degrees C), the annealing softening is related to recovery and recrystallization. When the annealing temperature is high ( 480 degrees C-580 degrees C), the annealing softening is primarily caused by recrystallized grain growth and the coarsening of second-phase particles.
10.1016-j.mtcomm.2023.105524	5	materials; thermal; heat; properties; material; welding; sintering; fusion; strength; laser; heat sink; thermal conductivity; mechanical; sink; manufacturing	Anneal-resistant copper alloys have been developed to address the need for stronger yet lighter fin and tube parts in heat exchangers, in order to facilitate greater efficiency and increased temperature capability. As such, brazing as opposed to traditional soldering has become the preferred joining method for these materials, due to the enhanced high-temperature properties of such joints. Copper-based filler metals are used extensively for the brazing of these materials, generally based on the copper-phosphorus system with alloying additions. In the present study, the microstructural issues arising from the current commercially available filler metals are dis-cussed and addressed through CALPHAD-supported alloy design. Three selected novel compositions were used in the brazing of pure copper as a test of the design concept. Alloy compositions in weight percent of Cu(bal.)- 7Ni-4Sn-5 P and Cu(bal.)-10Ni-2Sn-6.5 P were found to result in a reduction of brittle Cu3P phase while increasing the fraction (0.78 and 0.77 respectively) of copper-rich solid solution in joints post-braze, comparing favourably to commercial Meta-BrazeTM 077 under similar conditions (0.61). Furthermore, the copper-rich solid solution was leaner in tin, predicted to impart an increased melting temperature while microhardness profiles indicate increased joint ductility. The implications for mechanical properties of filler metals in this alloy family are discussed.
10.1016-j.mtcomm.2023.105796	-1		For the first time, a room-temperature meniscus-confined electrochemical additive manufacturing (MC-ECAM) process is evaluated as a potential decorative art technology for fabricating copper metal. The MC-ECAM has proven to be an excellent method for large-scale printing of decorative copper artworks such as warli art, plant leaves, and paintings. The inherent nature of the MC-ECAM process has the potential to eliminate the traditional time-consuming route to producing such copper microstructures and provide a one-step and efficient solution. The TEM and FE-SEM results revealed that well-oriented microstructures are prepared without surfactant, indicating the ECAM self-assembly mechanism. A small amount of zinc is added to the copper system to prevent corrosion. The XRD analysis also revealed the formation of copper metal, which barely changed even after 10 months of atmospheric ageing with the addition of 2% zinc. The XPS results show that zinc provides excellent stability for the ECAM-printed copper microstructure, further examined by an electrochemical corrosion study. Zinc act as a barrier to corrosion, and the results show that the Cu-Zn 2% exhibits excellent corrosion resistance than the pure copper microstructures.
10.1016-j.mtcomm.2023.106485	-1		A series of Cu-Ti alloys have been prepared by the liquid-solid reaction approach at a high vacuum environment. Resultant solidified microstructures have demonstrated highly-eutectic features, which are mainly composed of typical CuTi and CuTi2 phases. Vicker hardness tests have shown that the hardness values of CuTi and CuTi2 are 304 & PLUSMN; 15 HV and 683 & PLUSMN; 27 HV, respectively. Quantitative phase identification has indicated that, as the Ti content increases from 53 at% to 61 at%, the volume fraction of eutectic structure increases initially but decreases afterward, which are 18.8 & PLUSMN; 3.4%, 94.6 & PLUSMN; 3.5% and 54.4 & PLUSMN; 4.5%, respectively. The optimal wear performance has been achieved when the Ti content reaches 57 at%, which is concurrent to the highest volume fraction of the eutectic structure (94.6 & PLUSMN; 3.5%). Our findings may pave a viable yet economic way of fabricating wear resistant alloys in a controllable manner.Data availability: No data was used for the research described in the article.
10.1016-j.mtcomm.2023.106518	-1		In this work, the number and size of Sn-rich phases were found to be different in Cu-9Ni-6Sn alloys with the different Nb addition. A low fraction of Sn-rich phases, located between secondary dendrite arms, was achieved in the Cu-9Ni-6Sn-0.05 Nb alloy. The subsequent hot deformation behavior of Cu-9Ni-6Sn-(0.05 Nb) alloys was investigated at a temperature range of 750 & DEG;C -850 & DEG;C and a strain rate of 0.01 s  1. The results revealed that the different distribution of Sn-rich phases changed the dynamic softening mechanism in two alloys during hot compression. Due to the distribution of a large number of Sn-rich phases in the grain interior, the dynamic softening mechanism observed during hot compression in Cu-9Ni-6Sn alloy was particle stimulated nucleation (PSN) and continuous dynamic recrystallization (CDRX). In contrast, the major dynamic softening mechanism in Cu-9Ni-6Sn-0.05 Nb alloy were discontinuous dynamic recrystallization (DDRX) and CDRX due to a different distribution of Sn-rich phases. This study provides a fundamental guide for further research on Cu-Ni-Sn alloy fabrication based on the results of dynamic softening mechanisms obtained from the hot compression experiment.
10.1016-j.mtcomm.2023.106605	-1		The good properties of self-lubricating phase MnS in steel inspire us that MnS can improve the mechanical and tribological properties of Cu, while the poor wettability of MnS with the Cu matrix become the key problem of MnS/Cu self-lubricative material. Here we proposed an in-situ internal vulcanization method to improve the interface bonding, and produced MnS/Cu material by vulcanizing of Cu-Mn alloy powder at high temperature. After sintering, the Mn element in the Cu-0.15 wt% Mn (LMn) and Cu-0.84 wt%Mn (HMn) alloy forms MnS/Cu material recorded as LMnS and HMnS. After forging, the yield strength of LMnS and HMnS samples are 74 MPa and 89 MPa, respectively, which are 19.4 % and 43.5 % higher than that of pure copper. And the friction coefficients are 0.21 and 0.15, which are 34 % and 53 % lower than that of pure copper. The microstructures illustrated that the high strength and low friction are mainly ascribed to the second phase strengthening and self-lubrication action of MnS.
10.1016-j.mtcomm.2023.106612	-1		The presence of the fcc Cr-rich precipitates is a significant factor for the excellent performance of Cu-Cr alloys. In this work, we proposed an efficient approach based on machine learning to study on the alloying element distributions of the fcc Cr-rich precipitates in Cu-Cr alloys. The random forest algorithm with lower mean absolute error was selected for the classification of alloying elements. The alloying elements Mg, Si, Sc, Ti, Co, Ni, Y, Nb, Ag, In and Sn were classified into two groups. Sc and Ni were located mainly on the periphery of the fcc Cr-rich precipitates, while others were distributed randomly in the fcc Cr-rich precipitates, which was basically consistent with the ab initio results. The distribution of V was also determined experimentally and predicted via machine learning, and excellent agreement was found among experiment, machine learning and ab initio calculation. This work can provide an effective way to investigate the distribution tendency of alloying elements for various kinds of precipitates.
10.1016-j.mtcomm.2023.106762	-1		For investigating the effect of the admixture method of CoCrFeNi high-entropy alloys (HEAs) in Cu matrix composites on its microstructure and properties, the mechanically mixed CoCrFeNi-Cu powder, and gas atomization CoCrFeNi-Cu powder are prepared by spark plasma sintering technique, respectively. Several intermediates with core-shell structure exist in the specimen which is prepared using CoCrFeNi-Cu powder owing to the inter-elemental diffusion. It is assumed that the core-shell structure is effective in hindering grain deformation during cold rolling process and thus improves mechanical properties of the composites. The electrical conductivity, microhardness, and predicted ultimate tensile strength of the specimen prepared by mechanical mixing of Cu and CoCrFeNi powders were 69.09% IACS, 139.93 HV and 525.9 MPa, respectively.
10.1016-j.mtcomm.2023.106824	14	strength; properties; conductivity; electrical; mechanical; cu-; grain; mpa; electrical conductivity; aging; precipitation; phase; mechanical properties; tensile; phases	The effect of the rare earth element Ce on the morphology evolution, mechanical properties, and thermal stability of the Fe phase in the Cu-5Fe alloy was investigated. Experimental results demonstrate that adding Ce to the Cu-5Fe alloy significantly improves its comprehensive properties, with the tensile strength of the Cu-5Fe-0.1Ce alloy reaching 534 MPa and the electrical conductivity reaching 71% IACS after aging at 350 degrees C for 1 h . Compared to the Cu-5Fe alloy, the tensile strength experienced an increment of 93 MPa, while the electrical conductivity decreased only by about 2% IACS. The addition of Ce promotes the precipitation of the primary Fe phase, refines the Fe phase, and increases the density of Fe fibers, resulting in excellent mechanical properties. In addition, the thermal stability and grooving kinetics of Fe fibers were assessed. The primary mechanism of Fe fiber structural instability is the thermally-induced grooving at a triple junction where the grain boundary meets the Cu/Fe phase interface. The Fe phase is more likely to form thermally induced grooves and fractures during the aging process due to its high grain boundary energy. Adding Ce to the alloy slows down the expansion of grooves, playing a role in improving the thermal stability of the alloy.
10.1016-j.mtcomm.2023.106888	-1		ABS T R A C T In this study, the corrosion resistance and electrical and mechanical properties of 20 mil pure copper (Cu) and copper-phosphorus (CP) micro-alloyed wires were investigated. The experimental results show that both wires are equiaxed crystals containing twinning boundaries, and their similar grain sizes result in similar tensile properties and hardness values. In addition, both wires exhibit similar electrical performance characteristics; however, the CP wire has a more stable dynamic resistance and electrothermal impedance. The chloride corrosion tests showed that both wires experience pitting corrosion on the surface; chloride ions mainly corrode the twin boundaries and then the grain boundaries, which delays the corrosion process and prevents the sig-nificant degradation of the wire's electrical properties after chlorination. Considering the application of wires in insulated gate bipolar transistors (IGBTs), the wire failure mechanism was evaluated through electrical and mechanical tests, including tests of the electrothermal fatigue mechanism to determine the electrical properties and bending fatigue tests to determine the mechanical properties. When subjected to chloride corrosion, the CP wire has fewer twin boundaries and a lower boundary corrosion resistance, resulting in a better basal effect that improves the corrosion resistance and promotes work hardening during bending. As a result, the CP wire has a longer current cycle life and better bending fatigue properties than the Cu wire. This confirms the excellent application reliability of CP wires subject to corrosion.
10.1016-j.mtcomm.2023.107085	-1		High strength and high conductivity Cu-0.67Cr-0.3Zr alloy was prepared by vacuum directional solidification equipment. The face centered cubic (FCC) and body centered cubic (BCC) Cr rich precipitations in Cu matrix were characterized by high resolution transmission electron microscopy. In the as cast and solution treated state, a large amount of coherent FCC Cr precipitates is uniformly distributed in the matrix. These FCC Cr precipitates are covered by close packed {111} crystal planes and presents regular morphology. Due to their small size and cube-cube orientation with the matrix, FCC Cr precipitates follows dislocation shearing mechanism, resulting in limited strengthening effect. After aging treatment, both incoherent ordered nearly spherical and incoherent rodshaped BCC Cr precipitates were formed in the matrix. These incoherent precipitates always follow dislocation bypassing mechanism. Due to its small size and high-volume content, the spherical precipitation plays a major role in improving the strength of the alloy. On the contrary, the influence of rod-shaped precipitates on strength is minimal. According to the minimum free energy theory and local chemical potential equilibrium requirement, the precipitation with Kurdjumov-Sachs (K-S) orientation relationship tends to be rod-shaped extending along the direction of Cu [110] and Cr [111], while the precipitation with Nishiyama-Wassemann (N-W) orientation relationship tends to be nearly spherical.
10.1016-j.mtcomm.2023.107224	-1		A Cu-15Ni-8Sn alloy was prepared by electromagnetic stirring (EMS) based on the traditional melting casting method. The effects of electromagnetic stirring current on the dendrite structure characteristics, Sn element distribution, tensile strength, and elongation of the Cu-15Ni-8Sn alloy were studied, and appropriate electromagnetic stirring current parameters were selected. The relationship between the characteristics of the precipitated phase and the orientation of the matrix under the electromagnetic stirring current was analyzed, and the mechanism of fine crystal strengthening induced by the electromagnetic field was discussed. The results showed that EMS was beneficial for dendrite thinning. As the stirring current increased from 0 A to 140 A, the dendrite structure gradually changed to a rosette structure. When the stirring current was 30 A, the minimum secondary dendrite spacing was approximately 35.18 mu m, and the grain boundary width was reduced to approximately 10 mu m, The Sn element fluctuation range in the matrix was also the smallest, and the precipitate phase was dominated by the CuNi2Sn phase, which had a coherent relationship with the matrix. At this time, the tensile strength and elongation of the alloy were 520.82 MPa and 9.72 %, respectively. The forced flow caused by EMS promoted the temperature field in the melt to become uniform and inhibited the growth of dendrites. The flow of high-temperature molten liquid led to the remelting of dendrite arms, which produced a large number of dendrite fragments, refined the dendrites, and significantly improved the mechanical properties of the alloy.
10.1016-j.mtcomm.2023.107288	-1		The current study primarily focuses on the development of microstructure in Cu-Fe alloys (with varying Cu concentration) solidified using the Aerodynamic Levitation (ADL) method. The solidified microstructure analysis is performed using different characterization techniques such as Scanning Electron Microscopy (SEM), X-ray Tomography, Energy Dispersive Spectroscopy (EDS), and Electron Backscatter Diffraction (EBSD). In addition, the total undercooling in the alloys is calculated as a function of Cu composition and is found to increase with Cu content in the alloys. The surface morphology of the sample changes from planer front in pure Cu and Cu75Fe25 alloy to cellular in Cu50Fe50, Cu25Fe75 and pure Fe. The sample tomography and SEM analysis reveal that pure Fe and Cu exhibit a single-phase structure and a distinct phase separated microstructure is observed in the case of Cu75Fe25, Cu50Fe50 and Cu25Fe75 compositions. The grain orientation mapping of the solidified sample using EBSD reveals a core shell structure of Cu-Fe alloys. In the case of pure Fe and Cu, the grain structure is influenced by undercooling level. The orientation relationship analysis of the phase separated Cu and Fe in the alloy does not provides any orientation relationship between the grains of Fe and Cu.
10.1016-j.mtcomm.2023.107403	-1		In order to obtain the best compromise between high strength and low resistivity it was decided to introduce a controlled content of copper (Cu) large grains in copper-silver (Ag-Cu) composite wires. Composite powders are prepared by mixing of 1 vol% Ag nanowires and bimodal Cu powder. The so-obtained composites powders are consolidated into cylinders (8 mm in diameter and 30 mm long) by Spark Plasma Sintering (SPS) at only 450 degrees C. The cylinders served as starting materials for room temperature wire-drawing (WD) for the preparation of fine wires (1-0.2 mm diameter). The microstructure of the cylinders and the wires was investigated by scanning electron microscopy imaging and electron backscattered diffraction analysis. The electrical resistivity and the tensile strength were measured at 293 K and 77 K. The electrical resistivity of the wires is the lowest when the large Cu grain content is the highest. Cu large grains greatly limit the electronic scattering, forming areas with few grain boundaries and no Ag/Cu interfaces and therefore can be considered as fast conduction channels. Conversely, the addition of Cu large grains leads to a moderate decrease in mechanical strength . By presenting a 12 % lower electrical resistivity and an equivalent ultimate tensile strength (UTS) wires with bimodal Cu matrix show a better compromise between low electrical resistivity and high UTS (0.45 mu omega cm, 1082 MPa at 77 K) compared to wires with a fine-grained Cu matrix (0.51 mu omega cm, 1138 MPa at 77 K).
10.1016-j.mtcomm.2023.107603	-1		This work systematically investigated and discussed the differences in microstructure and crystallographic characteristics between the horizontal and vertical directions of the Cu-Cr-Zr alloy prepared by laser powder bed fusion (LPBF) and analyzed the formation mechanism of the subgrains. A sample with a relative density close to full density (99.63 +/- 0.1%) was prepared. Strong texture existed parallel to building direction of < 110 > , and large geometrically necessary dislocations (GNDs) density were distributed within the grains. The proportion of large-angle grain boundaries was about 12% higher than that in the building direction due to the larger number of fine grains in the horizontal direction, and the average grain size was reduced by twice. Further stable sub-grains (similar to 368 +/- 99 nm) were attributed to substructure induced by dislocation networks, which was mainly the combined effect of large residual stress, low stacking fault energy, and internal heat treatment effects.
10.1016-j.mtcomm.2023.107627	-1		In this study, molecular dynamics simulations are employed to investigate the mechanical behaviors of copper/ high-entropy-alloy nanocomposites, in which high-entropy alloy nanowires are embedded in copper matrix. The obtained results show that the mechanical properties of these nanocomposites are significantly affected by the volume fraction of high entropy alloy nanowires. Specifically, the Young's modulus of the nanocomposites increases linearly with increasing volume fraction of nanowires. However, the yielding stress and ultimate tensile strength increase nonlinearly with increasing nanowire volume fraction from 0.1 to 0.5, while opposite trends are obtained as the volume fraction further increases to 0.6. Moreover, distinct mechanical characteristics are observed in nanocomposites with nanowire volume fractions below and above 0.5. Nanocomposites with a nanowire volume fraction below 0.5 exhibit four distinguishable regimes, while those with a nanowire volume fraction above 0.5 present six distinct regimes. Notably, partial dislocations and stacking faults are highly activated inside the copper matrix in nanocomposites with a nanowire volume fraction below 0.5 but within both the copper matrix and high entropy alloy nanowires in nanocomposites with a volume fraction exceeding 0.5. Furthermore, the study highlights the significant impact of strain rate on the plastic deformation of nanocomposites. Nanocomposites with a smaller volume fraction of nanowires demonstrate a higher strain rate sensitivity compared to those possessing a larger volume fraction. In addition, the mechanical properties of Cu/ HEA nanocomposites significantly depend on temperature.
10.1016-j.mtcomm.2023.107668	-1		Vibration-assisted machining technology can effectively improve the quality and efficiency of nano cutting, but the characteristics of atomic removal and the mechanism of damage formation have not been systematically studied. In this paper, copper-nickel alloy material is taken as an example. The characteristics of vibrationassisted nano cutting and the plastic deformation behavior of materials were revealed by molecular dynamics simulation. The simulation results show that vibration-assisted nano cutting reduces tangential force, lateral force, and total force, strengthens the anisotropy of atomic motion, and causes greater displacement and removal of Cu/Ni atoms. The intermittent contact is beneficial for the elastic recovery of workpiece atoms, releasing internal stress and atomic strain, reducing the depth of damage and the length of dislocation lines. The difference in surface/subsurface damage to the workpiece is relatively small with an amplitude of 1 angstrom. With amplitudes of 3 angstrom and 5 angstrom, and as the frequency increases, the complete lattice structure is destroyed, resulting in a significant decrease in the number of FCC structural atoms and RDF peak. However, an appropriate increase in frequency can increase the removal of Cu/Ni atoms, improve the topological structure, and reduce RMS. The HCP and BCC structural atoms affect the generation of dislocation lines, with an amplitude of 3 angstrom and a frequency of 7.5 GHz, achieving the minimum damage depth and dislocation line length . Excessive amplitude of 10 angstrom results in irreversibly severe damage to the surface/sub-surface of the workpiece. This study will provide a new approach for optimizing vibration-assisted nano-cutting technology and achieving low-damage nano cutting of alloy materials.
10.1016-j.mtcomm.2023.107675	-1		Copper-based composites with La contents of 0.02 wt%, 0.04 wt%, 0.06 wt%, and 0.08 wt% are prepared by spark plasma sintering using the rare earth element La and electrolytic Cu powder as raw materials. The influence of the La mass fraction on the properties of Cu-La relative to copper-based composites are explored by observing the microstructure and testing the density, hardness, and electrical conductivity. The results show that after La is added to Cu via spark plasma sintering, the originally arbitrarily oriented grains in pure copper are gradually adjusted to a preferred orientation. When 0.04 wt% La is added, the degree of preferred orientation in the copper-based composites increases. The strengthening mechanisms of La for copper-based composites are grain refinement strengthening, dispersion strengthening, solid solution strengthening and second phase strengthening. With increasing La addition, the hardness values of the copper-based composites increase: from 45.4 HV to 57 HV, and the tensile strength up to 215 MPa. When 0.04 wt% is added, the conductivity reaches the highest value of 88.2 %IACS. However, the addition of excessive La leads to excessive formation of the Cu6-La phase, which leads to an increase in the mechanical properties of copper-based composites but a decrease in the conductivity.
10.1016-j.mtcomm.2023.107691	-1		The Cu-Cr-Zr alloy lost its hardness during the supply of power to pantograph assembly in railways applications. The present study focused on the influence of piled-up material on the nanohardness behavior of Laser Powder Bed Fusion (LPBF) produced Cu-Cr-Zr alloy. The 100 indentations were carried out at 3000 mu N, 6000 mu N and 9000 mu N loads with the pitch distance of 1 mu m and 2 mu m. Electron back scatter diffraction (EBSD) analysis revealed that the crystallography texture formed on (100), (101) and (111) planes. The X-ray photoelectron spectroscopy (XPS) analysis on the indentation revealed the formation of CuO, Cu2O and CuCr2O4 oxide layers. The material lost 6.3% of nanohardness when the load was increased from 3000 mu N to 9000 mu N without the influence of piled-up material. However, the material at 9000 mu N exhibited 26.38% more nanohardness than 3000 mu N. The Cr precipitate resisted the indentation against the deformation of the behavior up to 3000 mu N. The nanohardness at 9000 mu N increased with the increase of the row and columns other than the first column due to the irregular mixing of front and side piled-up material. The nanohardness values at 6000 mu N and 9000 mu N will be lost as the piled-up material has no metallurgical bonding with the substrate. More CuO, Cu2O and CuCr2O4 oxide debris formed at 9000 mu N conditions than the other two load conditions.
10.1016-j.mtcomm.2023.107722	-1		With the development of transportation vehicles towards to the direction of heavy load and high speed, the requirement of Cu matrix brake materials was proposed for improving performance in both mechanical and thermal properties. The Cu-SiCf composites is a new kind of friction brake material. To investigate the structural effect of 3D network structured SiC form ceramic on the compressive strength and thermal expansion properties of Cu-SiCf composites, SiCf was synthesized using a template method in conjunction with reaction sintering, while Cu-SiCf composites were prepared using squeeze casting, and exhibiting a co-continuous phase structure. The results reveal that SiC form ceramic reinforcement and constraint mechanisms enhance the overall strength of the Cu alloy through the 3D network structure. SiC form ceramic plays a role in load transfer and overall strengthening of the Cu alloy. With the synergistic effects of these mechanisms, increasing the SiC form ceramic volume fraction improves the compressive strength and reduces the coefficient of thermal expansion of the Cu-SiCf composites.
10.1016-j.mtcomm.2023.107723	3	sma; shape; shape memory; memory; smas; superelastic; bars; damping; cu-al-mn; mechanical; bending; applications; numerical; sma bars; material	In this work, the mechanical behavior of Cu-Al-Be shape memory alloy (SMA) strands for applications in selfcentering systems is discussed. The influence of the mechanical response from the wire level to the strand level is evaluated in order to define the strand configurations that provide the best mechanical properties for seismic control applications. Therefore, a comprehensive numerical analysis of 1 x 7 and 1 x 19 strand typology constructions is performed. Two boundary conditions and two different core materials are assessed: ends fixed or free to rotate; and strand core made of SMA or a soft material. A multilinear flag-shaped model is used as SMA constitutive law, which is integrated into four different linearized cable models. To validate the numerical analysis, four 1 x 7 strand specimens are fabricated and subjected to cyclic tensile tests with strain amplitudes of 3.5% and 5.5%. The results show that the cable models considering the Poisson effect are the most stable numerically, although they rely on asymmetric stiffness matrices. The energy dissipation capacity is controlled by the material damping ratio (3.2%) regardless of the strand configuration. Therefore, optimum conditions are obtained when most layers develop the maximum strain capacity of the material. Thus, the fixed ends condition is the best choice if maximum strength is desired, since the ductility gained by increasing the helix angle is negligible regardless of the core material. For this condition, the helix angle must be the same for all the layers. On the other hand, the free ends condition is the best choice if maximum strain is desired, since the strength decays rapidly as the helix angle increases. A self-centering device based on CuAlBe SMA strands has been modeled, obtaining promising results for seismic protection of structures.
10.1016-j.mtcomm.2023.107729	-1		Cu-3Ni-0.7Si-xCr-0.05Mg (x = 0.1 and 0.4) (wt% nominal composition) alloys were fabricated to investigate the effect of Cr contents on properties evolution and precipitation behavior of Cu-Ni-Si alloy. The results of the property analysis show that trace addition of 0.1 wt% Cr element contributes a better strength (ultimate tensile strength of 823 MPa) after single cold rolling and aging treatment. The precipitation behavior is characterized by transmission electron microscopy. It is found that nanoscale FCC structural Cr precipitates shift into submicron Cr3Si particles with Cr content increasing from 0.1 wt% to 0.4 wt%. Meanwhile, such superior formation of Cr3Si particle decreases the fraction of 8-Ni2Si owing to quick consumption of Si element from Cu matrix. Further quantitative analysis of various strengthening mechanisms reveals that the changed precipitation behavior notably affects their strengthening contribution to Cr contained alloys, resulting in an increase of more than 5.6% in the Orowan-Ashby mechanism. Surprisingly, in the case of the aging state at a temperature of 460 degrees C for a duration of 2 h, it is confirmed that although a much larger strengthening effect origins from nanosized 8-Ni2Si precipitate, the strength variation relies more on the Cr precipitation. That is, the lower strength at higher Cr content is mainly caused by the lower strengthening effect from Cr element related phases. In addition, the effect of the addition of trace Cr element on the operating mechanism on conductivity is also clarified. The results are expected to provide an appropriate content of Cr element and a dependable processing theory guidance for improving the comprehensive properties of the Cu-Ni-Si alloys.
10.1016-j.mtcomm.2023.107737	-1		The comparison of microstructure evolution of Cu and Ta-2.5 W liner during explosively formed projectile (EFP) formation was studied. The electron backscatter diffraction method (EBSD) was used to statistically characterize the microstructure of the liner before and after deformation. Both recycled EFPs show strong fiber texture and different degrees of recrystallization. The center of the recycled Cu EFP has strong <001> and <111> preferred orientations along the EFP axis, and the density of the texture changes with the deformation strain. Cu EFP has extensive dynamic recrystallization, up to 88%, which is considered to be a traditional dynamic recrystallization mechanism, the temperature is the main controlling factor in the refinement process. On the contrary, the recycled Ta-2.5 W EFP has a strong <101> fiber preferred orientation, and almost no dynamic recrystallization occurs, large strain deformation is the main factor for the microstructure fragment.
10.1016-j.mtcomm.2023.107821	-1		This study aims to quantitatively compare the effects of alloying elements on the microstructures and mechanical properties of Cu-Si, Cu-Ag, Cu-Ti, and Cu-Zr binary alloys over an alloying content range up to 2 wt%. The alloys were produced using vacuum arc melting, followed by homogenization and cold-rolling into plates. Subsequently, the annealing response of the cold-rolled plates was examined over a temperature range of 200-700 degrees C. The as-cast alloys show distinct microstructural features attributable to the alloying elements. Following the homogenization and cold-rolling processes, substantial microstructural transformations were observed. The analysis of mechanical properties revealed that solid solution hardening played a dominant role in increasing strength in Cu-Si alloys. Cu-Ag alloys displayed a minor increase in strength with alloying content, implying the influence of Cu-Ag precipitates on strength . Conversely, Cu-Ti and Cu-Zr alloys demonstrated remarkable strength improvements due to the presence of intermetallic precipitates and grain size reduction. While all other alloys displayed an inverse relationship between strength and elongation with increasing alloying content, the Cu-Si alloys exhibited a simultaneous enhancement of both strength and elongation. This effect can be attributed to the twinning-induced plasticity, brought about by the reduction of stacking fault energy in Cu through the addition of Si.
10.1016-j.mtcomm.2023.107961	-1		The microstructural evolution and dry friction wear performance of the Cu-15Ni-8Sn-0.5Co alloy during deformation and aging treatment were studied using optical microscopy (OM), scanning electron microscopy (SEM), transmission electron microscopy (TEM), and three-dimensional surface profilometry. The results show that the peak hardness of the Cu-15Ni-8Sn-0.5Co alloy initially increases and then decreases with increasing cold deformation, reaching a maximum hardness of 440 HV at 70 % cold deformation. During the aging process at 400 celcius, the phase transformation sequence of the Cu-15Ni-8Sn-0.5Co alloy with 70 % cold deformation is as follows: modulated structure-D022 ordered phase-gamma-D03 phase. The rapid formation of the D022 ordered phase, which is coherently dispersed within the matrix, is the main reason for the significant improvement in the mechanical properties of the alloy. However, the rapid nucleation and growth of the discontinuous precipitation structure are responsible for the reduced mechanical performance and limited resistance to over-aging in the alloy. Additionally, it also causes decreased friction and wear resistance in the alloy with 70 % cold deformation. At a load of 20 N, the primary wear mechanism of the peak-aged Cu-15Ni-8Sn-0.5Co alloy with 70 % cold deformation is abrasive wear. As the load increased to 120 N, the wear mechanism shifted to a combination of abrasive wear and fatigue spalling wear in the alloy.
10.1016-j.mtcomm.2024.108027	6	grain; deformation; strain; strength; dislocation; cu-; tensile; size; ecap; grain size; sfe; ductility; hardening; high; stress	To examine the influence of prefatigue on the uniaxial tensile properties of a Cu-3at%Al alloy with a high stacking fault energy (SFE), the prefatigued tests are carried out at different total strain amplitudes ranging from 1.0 x 10(-3) to 5.0 x 10(-3) up to the same accumulated plastic strain of 31, and uniaxially tensile tests are subsequently conducted on these prefatigued alloy specimens. With increasing strain amplitude, the induced fatigue dislocation structures change from elongated veins and planar stacking faults to dislocation walls and cells. For the Cu-3at%Al alloy specimen prefatigued at an intermediate Delta(t)/2 of 2.3 x 10(-3), the induced microstructure consists of loose cells, walls and few ill-developed persistent slip bands, which allows for an increase in dislocation storage rate but nearly does not affect dislocation annihilation rate during tensile deformation, thus exhibiting a higher strain hardening capability; therefore, the tensile strength can be improved nearly without loss of uniform elongation compared to the unfatigued specimen. In a word, an appropriate low-cycle prefatigue treatment can cause, to some extent, a strengthening effect on the static mechanical properties of high SFE metals, but such a strengthening effect is not as significant as the case for low SFE metals.
10.1016-j.mtcomm.2024.108111	-1		Etching is a precise chemical material reduction processing method that can get small and precise components with specific size and pattern. In etching of the high-precision lead frames, microstructure of the Cu alloy plate has become an important factor that affects the etching rate, size accuracy and surface roughness of the etched products. In this study, the CuCrSn alloy samples with different grain size were etched by aqua regia and then comprehensively characterized to reveal the effects of grain orientation and grain size on the etching behavior. The results show that the etching morphologies and rates of the Cu alloy grains are significantly different and dominated by the grain orientation, and etching of the grains with their surface nearly parallel to the {100} crystal planes are the lowest, meanwhile the roughness of these etched surfaces is the lowest. After the etching, the grain surfaces show very fine stepped structures composed of two or more {100} crystal planes along which the Cu atoms dissolve. The priority corrosion is prone to occur at the grain boundaries (GBs), and the etching around the GBs is more significant when the grains are finer. With the increase in grain size, the etching at the GBs become less apparent, and the difference in etching rates between different grains increases, results in height difference and an increase in roughness of the etched surfaces.
10.1016-j.mtcomm.2024.108136	-1		Copper/graphite composites have received much attention in engineering applications due to their excellent thermal, electrical and self-lubricating properties. However, their mechanical and wear resistance properties are usually limited by the brittleness of graphite and the poor interfacial bond between graphite and copper. Harder particles can be used to reinforce composites to increase their mechanical properties and wear resistance. In this paper, copper/graphite composites added with Ti3AlC2 particles were prepared by rapid hot press sintering. Studies were conducted to find out how the sintering temperature affected the composites' phase composition, morphology, hardness, relative density, and friction properties. The results showed that the relative density and hardness of the composites increased and then decreased with increasing sintering temperature. Besides, the findings indicated that Al atoms started to diffuse out of Ti3AlC2 and into the Cu matrix around 800 degrees C, leading to the in-situ formation of TiCx and Cu(Al) alloys. When the sintering temperature exceeded 850 degrees C, Ti3AlC2 decomposed essentially completely. In comparison to other similar prior findings (the wear rate was similar to 1 x10(-4) mm(3)center dot N- 1 center dot m(- 1)), the copper/graphite composites prepared in this work shown improved wear resistance. Among them, the lowest wear rate (1.942 x 10(-5) mm(3)N(-1)center dot m(- 1)) was obtained at a sintering temperature of 900 degrees C, with a relative density of 98.41%, a hardness of 75.67 HV and an average coefficient of friction of 0.15. This will help to further broaden the application areas of copper/graphite composites.
10.1016-j.mtcomm.2024.108152	15	aging; strength; conductivity; electrical conductivity; electrical; mpa; treatment; strengthening; degrees; cu-; cold; precipitation; tensile strength; tensile; iacs	The effects of solution and aging treatment on the microstructure and mechanical properties of Cu-7Ni-7Al-4Fe-2Mn alloy were studied by means of optical microscope(OM), scanning electron microscope(SEM), transmission electron microscope(TEM) and an electronic tensile testing machine. The results show that the microstructure of the as-cast alloy is mainly composed of an alpha-Cu matrix, Fe3Al particles and NiAl phase distributed at the grain boundaries. After solution treatment, the distribution of bean-shaped Fe3Al particles in the microstructure of the alloy is more uniform than that of the as-cast state, and the larger square Fe3Al phase is redissolved and disappears. During the aging process, the NiAl phase is continuously precipitated in the grains. The strength and hardness of the alloy first increase and then decrease with the extension of the aging time. After aging treatment at 500 degrees C x 6 h, the hardness of the alloy is 231.4 HV, and the tensile strength is 538.5 MPa. The hardness is 78.8% higher than that of the as-cast state, and the tensile strength is 41.9% higher than that of the as-cast state.
10.1016-j.mtcomm.2024.108183	15	aging; strength; conductivity; electrical conductivity; electrical; mpa; treatment; strengthening; degrees; cu-; cold; precipitation; tensile strength; tensile; iacs	Copper matrix composites with excellent comprehensive properties can be obtained by combining copper and copper alloys with refractory metals. Cu-Ta and CuCrNb-Ta composites were fabricated by powder metallurgy. The hardness and conductivity of cold -rolled CuCrNb-1Ta, CuCrNb-3Ta, and CuCrNb-6Ta composites were 102.2 HV and 90.6% IACS, 120.4 HV and 88.0% IACS, 118.6 HV and 87.5% IACS, respectively. Cr2Ta was detected on the surface of Ta particles in the sintered CuCrNb-Ta composites, and a Ta@Cr2Ta core -shell structure formed. The mechanical properties and conductivity of the CuCrNb-Ta composites in sintered state + cold rolling treatment + aging treatment are higher than those of Cu-Ta alloys under the coordinated action of solution strengthening and precipitation strengthening. These findings are conducive to the development of high -strength copper -based composites.
10.1016-j.mtcomm.2024.108238	-1		Design: concept of dual-phase copper alloys was attractive to improve the mechanical performance of Cu. However, a systematic understanding of the interactions between second phase, twins, and dislocations in dualphase copper alloys during deformation was urgent for further strengthening their mechanical properties. Herein, models of dual-phase Cu-Fe alloys with different Fe contents were established and simulated to deeply investigate the interaction between Cu matrix and Fe-enriched phase during deformation as well as the dislocation proliferation and structural changes at the atomic scale. It was found that numerous dislocations and twins were produced in Cu matrix during the deformation process, while grain boundaries of Fe-enriched phases were able to effectively impede the movement of dislocations, resulting in an enhancement of the alloy's strength . Furthermore, new grain boundaries were appeared in the Fe-enriched phase of the dual-phase Cu-Fe alloys at higher strain rates, resulting in a certain grain refinement. With the increasing temperature, the main deformation mechanism of dual-phase Cu-Fe alloys were changed from dislocation slip to grain boundary slip. In addition, the additional Fe content can significantly strengthen the alloys, and the changes in the mechanical properties of dual-phase Cu-Fe alloys during deformation were verified via experiments.
10.1016-j.mtcomm.2024.108242	-1		Solid -solution strengthening is an effective method to increase the mechanical strength of metal alloys. Revealing the solid -solution strengthening mechanism based on the energy profile of the dislocation motion is vital for the non -empirical development of high -strength metal alloys. This study provides detailed energy profiles (i.e., energy surfaces) of the edge dislocation gliding motion under the effect of solute atoms, as well as the atomicscale origin of solute strengthening in face -centered cubic (FCC) Cu alloys. The maximum shear stress (tau max) required for the dislocation to leave the solute atoms (Ni, Co, and Mo, all with different sizes and stacking fault effects) was qualitatively evaluated by finite temperature molecular dynamics simulations. By the nudged elastic band (NEB) analysis, we determined the atomistic origin of the energy barrier for the edge dislocation motion and the maximum force required to overcome the solute pinning effect (i.e., depinning force, FNEB) in binary Cu alloys. By linking FNEB to the size misfit, a theoretical prediction model based on size effects and the volumetric strain field was used and can qualitatively explain the increment in the maximum shear stress (Delta tau max) by the solute atoms. These results provide an atomistic basis for the prediction of the solute -strengthening effect correlated with the edge dislocation motion in wide FCC systems.
10.1016-j.mtcomm.2024.108271	15	aging; strength; conductivity; electrical conductivity; electrical; mpa; treatment; strengthening; degrees; cu-; cold; precipitation; tensile strength; tensile; iacs	The synergistic effects of yttrium micro-alloying and heavy strain rolling deformation on the micro -structure and properties of Cu-15Fe alloy were investigated systematically in this work. The results indicate that trace yttrium element is beneficial to refine the Fe phase structure of Cu-15Fe alloys and reduce the distance between Fe fibers after rolling, which stimulates different strengthening mechanisms to optimize the mechanical properties of the alloy. The appropriate amount of yttrium atom in solution can promote the refinement of primary Fe phase and the precipitation of Fe particles, which can cooperatively improve the mechanical-electrical properties and high temperature anti-intenerate properties of the alloy. However, the excess yttrium element forms a network distribution of intermetallic compounds at grain boundaries, which reduces the overall performance of the alloy. When yttrium content is 2 x 102 ppm level, the comprehensive performance of Cu-15Fe alloy strip can achieve 706.9 MPa/198.1 HV/41.3%IACS. Moreover, the synergistic effect of rolling deformation and aging treatment can effectively reduce the interfacial energy of the alloy, decrease the interfacial scattering and promote the precipitation of Fe particles, which can optimize the electrical and mechanical properties of Cu-15Fe-Y alloy. The conductivity of yttrium micro-alloyed Cu-15Fe alloy strips was significantly improved to 56%IACS with aging treatment at 500 celciusx 120 min.
10.1016-j.mtcomm.2024.108325	-1		The study examines the changes in elastic parameters and mechanical properties and the evolution of texture of thin plate specimens of Cu-37Zn alloy strain-induced at room and cryogenic temperatures using ultrasonic impact treatment (UIT) with wave-reflecting anvil. The precise measurements of the mass densities (rho) and bulkwave ultrasonic velocities (vij) by means of the pulse-echo method using a home-made automated apparatus provides quantitative data regarding the Debye temperature TD, elastic (E), shear (G) and bulk (B) moduli, Poisson coefficient (eta), hardness HV, and Milman's plasticity parameter delta H, of the UIT-processed specimens. In addition, XRD, EBSD, TEM, and SAED analyses are used to characterize crystallographic texture and microstructure evolutions. As shown, the surface severe plastic deformation induced by multiple impacts during the UIT processing accompanied by ultrasonic vibrations results in an increase in TD, E, G, and HV and a decrease in eta, B, and delta H, which are more pronounced for air-UIT. Unusual dislocation activity is promoted by ultrasonic vibrations. Observed twinning and shear bands in cryo-UIT-ed specimen provide to the formation of the brasstype texture while the stress relaxation, unusual dislocation activity stimulated by ultrasonic vibrations and dislocation cell formation in the air-UIT-ed specimen leads to the copper-type texture. The longer UIT provides the nanostructuring regardless of the involved microscopic mechanisms and used temperature conditions.
10.1016-j.mtcomm.2024.108408	15	aging; strength; conductivity; electrical conductivity; electrical; mpa; treatment; strengthening; degrees; cu-; cold; precipitation; tensile strength; tensile; iacs	Cu-0.3Zr-0.05Cr and Cu-0.3Zr-0.15Cr alloys were prepared by vacuum melting method, and solution treatment was carried out at 900 C-degrees. In order to explore the best heat treatment process, the alloy was aged with different parameters. Through performance test and microstructure analysis, the following conclusions were drawn. After hot forging, 60% cold rolling, and 450 C-degrees 120 min aging treatment, Cu-0.3Zr-0.15Cr alloy exhibited favorable performance with 180 HV hardness, 467 MPa tensile strength, 84.4% IACS electrical conductivity, and 12.1% elongation. The Cu-0.3Zr-Cr alloys showed a considerable increase in texture content and maximum texture strength as the Cr concentration rose. The primary mechanism for strengthening alloys is precipitation strengthening. During the aging treatment, Cr and Cu5Zr phases are precipitated in the alloy. The Cr phase formed a semi-coherent interface with the Cu matrix, which allowed the alloy to retain its good flexibility. The dispersed precipitates greatly increased the strength and electrical conductivity of the alloy, resulting in outstanding overall performance.
10.1016-j.mtcomm.2024.108413	15	aging; strength; conductivity; electrical conductivity; electrical; mpa; treatment; strengthening; degrees; cu-; cold; precipitation; tensile strength; tensile; iacs	Cu-1Cr-0.1Zr and Cu-1Cr-0.1Zr-0.07La alloy sheets were prepared by the following process: vacuum casting- homogenization treatment- hot forging- solid solution treatment- cold rolling- aging treatment. The effect of trace La on the aging behavior and mechanical properties of Cu-1Cr-0.1Zr alloy was investigated. Compared to the Cu-1Cr-0.1Zr (0La) alloy, the Cu-1Cr-0.1Zr-0.07La (0.07La) alloy exhibited a significant increase in hardness and a slight decrease in electrical conductivity due to larger number of finer and coherent f.c.c Cr-rich precipitates. It was found that trace La can affects the evolution of precipitation phases. The thermodynamics calculation indicates that with La addition, the Cr-rich precipitates were much more inclined to nucleate with f.c. c structure, and the precipitation growth kinetics results indicate that the addition of La can reduce the activation energy of precipitation, promote the precipitation of f.c.c Cr phase and form Cr-poor zones, making it more difficult to form bcc nuclei. Thus, the transformation of nanoscale Cr-rich precipitates from f.c.c structure to bcc structure was inhibited due to trace La addition, causing higher hardness with appropriate conductivity.
10.1016-j.mtcomm.2024.108432	-1		Composition design is one of the effective methods to promote abnormal grain growth (AGG) behavior. In this study, a series of CuAlMnNi-Cr-x (x = 0, 0.5 and 1 at%) alloys are designed to study the effects of Cr on the AGG behavior during the cyclic heat treatments (CHTs) of CuAlMnNiCr alloy. The results indicate that adding 0.5% Cr can promote the AGG behavior, in which the average grain size of the (Cu71.6Al17Mn11.4)(97.5)Ni2.0Cr0.5 (0.5Cr) is about 1.5 times of that for (Cu71.6Al17Mn11.4)(98.0)Ni-2 (0Cr) after 2 CHTs. Remarkably, the activation energy of grain boundary migration (Q) of 0.5Cr (= 90 kJ/mol) is similar to that of 0Cr (= 91 kJ/mol), while the subgrain boundary energy (Delta G(s)) of 0.5Cr (= 6.9x10(-2) J/mol) is significantly higher than that of 0Cr (= 4.7x10(-2) J/mol). The higher subgrain misorientation of 0.5Cr (= 1.25 degrees), as compared with that of 0Cr (= 0.72 degrees) is the main reason. Thus, tuning Cr content can promote the AGG behavior of the CuAlMnNiCr alloy, through controlling the subgrain misorientation. Moreover, a maximum of 13.0% superelastic strain is obtained after adding 0.5% Cr.
10.1016-j.mtcomm.2024.108580	-1		Designing heterogeneous structures (HS) is recognized as a promising method to achieve high performance for Cu-based materials. However, how to tune and control stably still remains challenging. In this work, a reproducible method based on powder metallurgy and heat treatment is proposed for designing controllable HS. Herein, spatial distribution of coarse and fine grains can be controlled via addition of different volume fraction of Cu powder. The microstructure evolution of the resultant HSed material was characterized in detail by utilizing electron backscattered diffraction (EBSD) combined with a transmission electron microscope (TEM). An optimal heterogeneous geometric microstructure consisting of individual isolated micron-sized grain completely surrounded and constrained by the hard ultrafine-grained Cu-Cr0.67 matrix is discovered, which produced an excellent combination of high yield strength (531.4 +/- 10.3 MPa), uniform elongation (-22.1%),and conductivity (-90.4% IACS) (International Annealed Copper Standard). The well-dispersed and high-density soft/ hard zone interfaces in the resultant HS cause geometrically necessary dislocations (GNDs) piling ups, which produce extra strain hardening to enhance the strength and ductility. This reproducible method provides a feasible strategy to optimize the mechanical properties of metals via tailoring HS.
10.1016-j.mtcomm.2024.108611	-1		A Cu-0.3Fe-0.3Mn-0.16 P alloy with high strength and conductivity has been successfully prepared. The influence of integrated multistage thermo-mechanical treatment on the microstructure evolution and properties of the alloy was investigated experimentally. The results reveal substantial production of dislocations and nanosized MnFeP precipitates in the matrix, endowing the alloy with outstanding tensile strength (691 MPa), yield strength (662 MPa), and electrical conductivity (68.0% IACS). Moreover, the Cu-Fe-Mn-P alloy demonstrates excellent softening resistance, particularly at the elevated temperature of 525 degrees C. The yield strength of the alloy is attributed to strain strengthening, precipitation strengthening, and fine grain strengthening (in decreasing order of importance). Above 600 degrees C, the alloy exhibited softening behavior marked by recrystallization and the coarsening of precipitates. This research should assist in the development of innovative high-strength and highconductivity Cu-Fe-Mn-P alloys.
10.1016-j.mtcomm.2024.108617	-1		The optimum solid solution and aging processes for Cu-0.9Be-1.5Ni-0.04Y alloys, as well as the microstructure and strengthening mechanisms during aging were investigated. The results show that the optimum solid solution and aging temperatures are 980 degrees C and 480 degrees C, respectively. During aging treatment at 480 degrees C, the precipitation sequence of the Cu-0.9Be-1.5Ni-0.04Y alloy was supersaturated alpha solid solution -> GP zone -> gamma '' phase -> gamma ' phase -> gamma phase. As increasing the aging time, the microhardness and yield strength of the alloy showed a trend of increasing and then decreasing, with the maximum of 220.9 HV and 626 MPa, respectively. The strengthening mechanisms of the nanoscale gamma and gamma' phases in Cu-0.9Be-1.5Ni-0.04Y alloy were the shear mechanism and orowan mechanism, respectively. The electrical conductivity of the alloy increased and then remained more or less constant with increasing aging time, with a maximum of 39.78%IACS. The difference between the theoretical and measured values of the electrical conductivity of the alloy after aging at 480 degrees C for different times was less than 1%
10.1016-j.mtcomm.2024.108671	-1		Strengthening of Cu-Ti alloys with alloying elements is usually accompanied by decreasing of electrical conductivity. Previous study has found that the metastable phase (beta '-Cu4Ti) is coherent with Cu matrix which can greatly improve its mechanical performance. In the present work, first-principles calculation was employed to find potential alloying element which can improve the stability of the metastable phase (beta '-Cu4Ti); at the same time less amount of Ti atoms remains as solutes in order to maintain moderate electric conductivity. In total effects of 84 alloying elements on beta '-Cu4Ti stability were calculated, among which Gd was found to be possible to hinder the beta '-Cu4Ti dissolved into matrix. Experiments were carried out to confirm the behavior of Gd as alloying element.
10.1016-j.mtcomm.2024.108783	8	hot; deformation; strain; strain rate; dynamic; hot deformation; recrystallization; dynamic recrystallization; flow; rate; flow stress; compression; constitutive; degrees; stress	High strength and high elasticity copper alloys have good application prospects due to their excellent mechanical properties. The deformation and heat treatment in its preparation process are important steps to ensure the service performance. In this work, Cu -Ti based alloys were employed and hot compression experiments were conducted at 500-800 degree celsius under four different strain rates. Their constitutive equations and thermal processing maps were constructed. The influence of microalloying elements on activation energy was also analyzed. The microstructure evolution and recrystallization behavior under hot deformation conditions were studied based on the results of TEM. At the same time, Arrhenius, back propagation neural network (BPNN) and support vector machine (SVM) algorithms were used to predict the flow stress of the alloy. The results indicate that the relationship between flow stress and the input factors (strain rate, temperature and deformation) can be well predicted using the support vector machine algorithm. Microalloying can increase the activation energy of copper alloys, and the sensitivity of activation energy to temperature changes is related to the interaction between precipitates and dislocations.
10.1016-j.mtcomm.2024.108833	-1		Herein, the ultimate tensile strength and electrical conductivity of precipitation-strengthened Cu-Ni-Si alloys were simultaneously improved by utilizing a machine learning-based multiobjective design strategy. The multiobjective design strategy consists of five main steps: creating the initial dataset, generating alloy features, screening key alloy features, modeling and inversely designing, and experimental iteration. Of particular note is the constraint placed on the initial composition-properties dataset, considering the rules governing the addition of Co. This constraint ensures that the dataset adheres to the required specifications. To evaluate the optimized degree of the inverse design composition, a joint expectation improvement function was employed. This function effectively integrates the ultimate tensile strength and electrical conductivity. Through a process of five mutually reinforcing iterations of machine learning and experimentation, the combined property of the designed alloy surpasses the Pareto frontier initially formed by the collected data. Microstructure analysis further confirmed the significant precipitation strengthening effects achieved in the optimized alloy.
10.1016-j.mtcomm.2024.108858	15	aging; strength; conductivity; electrical conductivity; electrical; mpa; treatment; strengthening; degrees; cu-; cold; precipitation; tensile strength; tensile; iacs	Cu -Ni -Si alloy is extensively utilized as the main material for lead frames, and its preparation process and mechanical properties are closely related. In this work, two processing routes were employed to prepare Cu-1.8Ni0.45Si alloys. One (named traditional processing, TP) involves vacuum casting followed by hot rolling, while the other (named short processing, SP) involves downward continuous casting and CONFORM. The variation trend and mechanism of its tensile strength and elongation were analyzed by SEM, EBSD and TEM. The results showed that the tensile properties of Cu-1.8Ni-0.45Si alloy were greatly improved after CONFORM treatment. CONFORM enables Cu-1.8Ni-0.45Si alloy to facilitates enhanced internal deformation energy storage and grain boundary density in the matrix after cold deformation, making it easier for the aging process to further precipitate and grow Ni 2 Si phase. Compared with TP, the tensile strength of the alloy decreases slightly, but the elongation increases significantly.
10.1016-j.mtcomm.2024.108876	-1		A high-performance Cu-Cr-Zr alloy, including ultimate tensile strength of 669 MPa, elongation to fracture of 15.7% and electrical conductivity of 73.1% IACS is achieved by the optimized two-step thermomechanical treatment. The microstructure of the alloy is characterized by the scanning electron microscopy equipped with electron-backscattered diffraction and transmission electron microscope. The results show that the second phases are precipitated sufficiently by the optimization of the process of primary aging treatment, causing an increase in electrical conductivity without deteriorating the mechanical properties. This optimized process is helpful to obtain the finer grains, higher density of dislocations, ultrafine and denser precipitates in the matrix. The uniformly distributed Cr precipitates with average size of 3.07 nm are observed in the Cu matrix and have a strong pinning effect on the migration of grain boundaries and dislocations, resulting in an excellent combination between the mechanical and electrical properties in the Cu-Cr-Zr alloy. This work will provide a significant guideline for the fabrication of high-performance copper alloy through optimizing the thermomechanical process.
10.1016-j.mtcomm.2024.108884	-1		Two Cu-Cr-Nb alloys, denoted as alloy 1 (comprising Cu-0.89 at% Cr-0.42 at% Nb) and alloy 2 (comprising Cu1.84 at% Cr-0.99 at% Nb), were produced through a series of manufacturing processes including vacuum induction melting, melt spinning, consolidation, brazing, and baking, with both alloys aimed at achieving a nominal Cr-to-Nb atomic ratio of 2. Microstructural characterization using transmission electron microscopy and X-ray diffraction identified the cubic C15 Laves-phase Cr2Nb as the dominant precipitate in both alloys, crossvalidated by thermodynamic calculations and atomistic simulation-based density functional theory (DFT). Besides cubic C15 Cr2Nb, hexagonal C14-phase Cr2Nb and alpha-BiF3 cubic structured Cr3Nb were also observed in the alloys, including a coherent interface formed between the Cr3Nb precipitate and the Cu matrix. The hardness of the alloys increases, and the electrical conductivity decreases with increasing alloying addition content; two practical equations described the trends. Further DFT simulations revealed that the electrical conductivity (conductance) of the Cu/Cr2Nb interface is an order of magnitude higher than the intrinsic Cu high-angle grain boundaries.
10.1016-j.mtcomm.2024.108968	-1		Cu-Ni-Sn alloys have attracted attention in the electronics and electrical industries for their good mechanical properties and resistance to stress relaxation. The effect of Equal Channel Angular Pressing (ECAP) on the microstructural and properties of a Cu-9.0Ni-1.0Sn-0.5Si-0.5Al alloy were systematically investigated by means of hardness tests, tensile tests, conductivity measurements and electron microscope observations. After 8 ECAPed passes, initial coarse grains were significantly refined, and the average grain size decreased to 0.5 mu m. Grain refinement was related to the rotation of deformation twin and the movement of dislocations in the grains during ECAP processing, the strength increment of Cu-Ni-Sn-Si-Al alloy during ECAP was mainly attributed to the low-angle boundaries strengthening (sigma(SGB)). After aged at 400 degrees C for 300 min, the tensile strength, elongation and electrical conductivity of the 8 pass ECAPed sample were 976 MPa, 5% and 13.7% IACS, respectively. The spherical Ni3Al/Ni3Si and Ni3Sn precipitates with the size of about 6 nm formed in 8 pass ECAPed samples after aging. The orientation relationship (OR) between the Cu matrix and precipitates was[(11)over bar 1](Cu)//[(11)over bar 1](p) and [(2)over bar00](Cu)//[(1)over bar 00](p).
10.1016-j.mtcomm.2024.108983	-1		The high solubility, reactivity and solubility of supercritical water provide a new way for the preparation of advanced metal matrix composites. In this paper, Cu-Al2O3 composites are prepared by supercritical water liquid phase in situ reaction (SW -LIR). In this method, the Cu-Al atomized alloy powder are used as raw material, deionized water as reaction medium, H2O2 as liquid phase oxygen source, and the Cu-Al2O3 composite powder are prepared at 380 degrees C and 22.1 MPa for 10 min. The Cu-Al2O3 composite block is prepared by spark plasma sintering (SPS). The results show that Al2O3 has an average size of 41.8 nm and mainly exists in the form of mixed crystals. The interface with the matrix is coherent or semi-coherent. With the increase of Al2O3 content, the mechanical properties of the composites are obviously improved. When the Al2O3 content is 1.12 wt%, the microhardness is as high as 164.52 HV and the tensile strength is 441 MPA, while still maintaining a high electrical conductivity (75 %IACS). At the same time, it shows quite excellent high temperature performance. It can still retain the characteristics of high strength at 1000 degrees C, which solves the shortcomings of high thermal conductivity but low strength of pure copper. Compared with the traditional method, SW -LIR method has the characteristics of low reaction temperature, fast reaction speed and green environmental protection.
10.1016-j.mtcomm.2024.109030	-1		Cu-Cr-Sn-Zr-xZn alloys with different Zn contents (0.087, 0.26, and 0.42 wt%) were prepared by vacuum casting, and the microstructure and properties of these alloys were investigated using different detection methods. The results show that the Zn element could promote the formation of some primary phase Cr particles and parts that were stretched into fibers during cold drawing deformation, thus enhancing the strength of these alloys. Meanwhile, the number of twins in these alloys increases with the increase in Zn content. When Zn content is 0.42%, the Cu0.64Zn0.36 phase is generated, which could play a role in the second phase ' s strengthening. The Cu-0.97Cr-0.096Sn-0.068Zr-0.42Zn alloy shows high tensile strength and electrical conductivity properties of 832 MPa and 72%IACS, respectively.
10.1016-j.mtcomm.2024.109195	-1		Both high strength and superior corrosion resistance are necessary for Cu-Ni alloys when serving in marine engineering. We discover that the corrosion resistance and strength of Cu-7Ni-3Al-1Fe-1Mn alloy can be enhanced via rare earth Sm microalloying. When Sm content is 33 ppm, the alloy exhibits not only the lowest corrosion rate, which is 40% lower than the Sm-free alloy, but also the maximum tensile strength, which is 6% higher than the Sm-free alloy. After alloying 33 ppm Sm, the average grain size of Cu-7Ni-3Al-1Fe-1Mn alloy is reduced by 42%, from 205 mu m to 118 mu m. In addition, CuSm phase and (Sm 2 S 3 -Al 2 O 3 ) composite phase appear in the alloy after alloying 33 ppm Sm. The improvement of corrosion resistance is primarily due to the formation of Cu-Sm precipitates, leading to a positive shift of the corrosion potential. Further analysis indicates that the increased strength can be mainly attributed to grain refinement and the formation of Sm-S precipitations. This work promotes a new method for enhancing the strength and corrosion resistance simultaneously of copper alloy.
10.1016-j.mtcomm.2024.109304	-1		Rare earths are often added to copper alloys as trace alloying elements to modify the structure and improve related properties. In this study, the Cu-7.8Sn-0.16 P and Cu-7.8Sn-0.16 P-0.15La alloy strips were fabricated through full-chain process of vacuum casting, cold rolling, intermediate annealing, cold rolling and low temperature annealing process. Then, the distinctive microstructure features and mechanical properties of Cu-7.8Sn0.16 P and Cu-7.8Sn-0.16 P-0.15La alloys were comprehensively analyzed in special view of rare earth affected phase types and property evolution. The results indicate that the addition 0.15 wt% La has effectively refined the dendrite segregation and dispersed the microporosity. Specifically, La combines with P and form a stable and dispersed micron sized LaP2 intermetallic compound, which replaces the low melting point (alpha+6+Cu3P) ternary phase in the La-free alloy. Furthermore, a new nanoscale La(Cu2P)2 precipitated phase is characterized in the Cu7.8Sn-0.16 P-0.15La alloy during low-temperature annealing process. As well, the tensile strength of Cu-7.8Sn0.16 P-0.15La strips display notable increase to 915 MPa from 834 MPa of Cu-7.8Sn-0.16 P after low-temperature annealing. Such increase in tensile strength is attributed to the formation of La-containing phase of varied sizes in the Cu-7.8Sn-0.16 P-0.15La alloy, where the nano scale La(Cu2P)2 precipitated phase makes the most significant contribution.
10.1016-j.mtcomm.2024.109317	-1		As brazing devices become more sophisticated and service environments become more demanding, Cu-Ag-ZnMn-Ni-Si-B-P brazing material are subjected to higher wettability and brazed joint strength requirements. In this paper, a machine learning strategy is proposed. Firstly, the composition-process-properties dataset is obtained based on high-throughput experimental techniques. Then, the composition features are constructed by elemental chemical and physical parameters instead of the direct input of alloy composition, and the proposed novel feature selection method is used to effectively identify the key composition feature combinations that affect brazing properties. Then, the support vector regression algorithm was used to establish a joint strength model with an error of less than 3.47 % and a spreading area model with an error of less than 8.37 % using the key alloy composition features and brazing process features as inputs, respectively. Finally, two multi-objective optimization strategies, Bayesian optimization and NSGA-II genetic algorithm, were used for the integrated optimization design of composition and brazing process. The experimental results show that the Cu-14Ag-4Zn-24Mn13.5Ni-0.4Si-0.3B-0.3 P alloy and the matched brazing process (945 degrees C and 12 min) were optimally designed using NSGA-II genetic algorithm, corresponding to the measured joint strength and spread area of 356 MPa and 412 mm2, respectively, which outperforms the high-throughput experimentally optimized data as well as commercialized data. The machine learning strategy established in this work provides a new research idea for the comprehensive improvement of brazing properties of brazing alloys with small data sets.
10.1016-j.mtcomm.2024.109438	14	strength; properties; conductivity; electrical; mechanical; cu-; grain; mpa; electrical conductivity; aging; precipitation; phase; mechanical properties; tensile; phases	The aging process plays a pivotal role in shaping the microstructure of Cu-Ni-Si alloys, a typical kind of precipitation-strengthened Cu alloy. This process significantly affects both the mechanical and electrical properties of the final Cu alloy strips. In this study, Cu-Ni-Si alloy sheets underwent a 90 % reduction through cold rolling at room temperature, followed by heat treatment at temperatures ranging from 400 to 650 degree celsius. A comprehensive investigation was conducted into how cold rolling deformation and the aging process affect the alloy's microstructure, as well as its mechanical and electrical properties. The analysis was performed using a scanning electron microscope equipped with a backscattered electron diffraction system (SEM-EBSD), complemented by transmission electron microscopy (TEM). The findings revealed that recrystallization and precipitation occurred concurrently and were both enhanced by higher temperatures and prolonged heat treatment durations. However, recrystallization at elevated temperatures has a marginal impact on enhancing electrical conductivity and results in a significant reduction of mechanical properties. In contrast, alloys preserving the deformed microstructure benefit from multiple strengthening mechanisms, including precipitation, dislocation, grain boundary, and texture strengthening. This study offers quantitative insights into the precipitation and recrystallization behaviors of Cu-Ni-Si alloys, contributing significantly to a deeper understanding of the mass production of high-performance copper alloys.
10.1016-j.mtcomm.2024.109707	15	aging; strength; conductivity; electrical conductivity; electrical; mpa; treatment; strengthening; degrees; cu-; cold; precipitation; tensile strength; tensile; iacs	A type of Cu-Ni-Co-Si alloy was designed and conducted by solid solution and aging treatments. Meanwhile its microstructure evolution and performance evolution were also studied. The characteristics of precipitated phases after aging treatment, and the strengthening mechanism of the process have been thoroughly studied. The results indicate that the optimal process for Cu-Ni-Co-Si alloy is solid solution at 900 degrees C for 120 min and aging at 500 degrees C for 240 min, respectively. At peak aging, the alloy reached tensile strength and conductivity of 631 MPa and 41.3 % IACS, respectively. The grain orientation of the aged alloy is complex; besides it is equiaxed; and there are a large number of twins and dislocation lines in the crystal. The matrix contains both Co2Si large-grained precipitated phases and orthorhombic, nanoscale precipitated phases of (Ni,Co)2Si; with sizes in the range of 5-8 nm. (Ni,Co)2Si is the main strengthening phase of the alloy after aging treatment due to its fineness and diffuseness. Solid solution and aging treatment improve microstructure and comprehensive properties of materials, and validated the theoretical guidance and feasibility in practical applications through high-precision quantitative calculations.
10.1016-j.mtcomm.2024.109708	-1		In this paper, two different fabrication processes, mainly including Hopkinson bar (HB) + cold rolling (CR) method (process I) or CR + CR method (process II), were carried out to fabricate the Cu-11Al-3Ni alloy sheet. The role of the HB method on the microstructure and mechanical properties of the Cu-11Al-3Ni alloy was investigated in detail. Due to the vast discrepancy in strain rates between the HB (102-103 s- 1) and CR (10- 2-10-3 s- 1) processes, the fraction of twins in the HB + CR sample was attached 14.7 %, much higher than the 1.68 % of the CR + CR sample, accompanied by the increase in the frequency of recrystallised grains and the enhancement of BRASS texture component. In addition, due to the generation of fine and numerous twins and the resulting twin strengthening (sigma twin), the performance of tensile strengths (including yield strength and ultimate tensile strength) in the HB + CR sample were 868 and 1051 MPa, respectively, much higher than those of the CR + CR sample (734 and 940 MPa). Consequently, the HB method was considered to be as a potential approach to obtaining ultrahigh-strength Cu alloys.
10.1016-j.mtcomm.2024.109802	-1		The Cu-Ni-Si alloy clad AA8030 alloy rod was prepared by continuous casting composite technology with gradient-varying drawing speeds, and the influences of drawing speed on the casting quality and microstructure of Cu-Ni-Si alloy clad AA8030 alloy rod were systematically studied. The drawing speed at which satisfactory continuous casting quality could be obtained was 90-120 mm/min. Meanwhile, axial columnar grains favorable for subsequent plastic processing were obtained, although the angle between columnar grains and axial direction increased with the increases of drawing speed. Moreover, with the drawing speed increasing from 90 mm/min to 120 mm/min, the thickness of composite interfacial layers was significantly increased, and the morphology of interfacial phases was gradually changed. The Cu-Ni-Si alloy cladding layer was cut from the composite to perform solution and aging experiments. The results showed that the solid solution effect of the as-cast Cu-Ni-Si alloy was consistent with that of the solution-treated Cu-Ni-Si alloy because of the rapid cooling characteristics of continuous casting composite technology, which solved the problem that the composite rod could not be solution treated as a whole due to the lower melting point of the Al core.
10.1016-j.mtcomm.2024.110195	-1		Two layers of FeCoNiCrAl coatings were prepared on copper (Cu) alloys substrates in this paper in order to improve the wear and corrosion performance of Cu alloys and to reduce the dilution of Cu in the laser cladding (LC) process. The microstructures, phase composition, microhardness, and crystal structure of the resulting coatings were analyzed, and their high-temperature tribological and electrochemical properties were tested. The results show that the surface of the HEA coatings still consists of a single-phase body-centered cubic (BCC) with low Cu content, and no generation of a second phase was observed. Compared with the substrate, the FeCoNiCrAl HEA coatings have better wear resistance, with oxidative wear and slight adhesive wear as the wear mechanism at 250 degree celsius. In addition, the FeCoNiCrAl HEA coating showed better electrochemical corrosion performance in 3.5 wt% NaCl solution. The corrosion mechanism is that the dense oxide layers inhibit the erosion of Cl-- and high reaction barriers slow down electrochemical reactions.
10.1016-j.mtcomm.2024.110370	-1		In this work, Cu-10Sn-xNi (x = 0, 3, 6, 9, and 12 wt%) alloy coatings were prepared using laser cladding technology. The influence of Ni content on the phase composition, microstructure, crystallographic characteristics, microhardness, electrochemical corrosion, dry sliding wear and corrosive wear behavior of the coatings were studied. The results indicated that the coatings formed good metallurgical bond with the substrate. The coatings were composed primarily of the alpha-Cu matrix and small gamma precipitates. The Ni element effectively reduced component segregation, and with the increased of Ni content, the grain size in the coating was significantly refined, resulting in fine equiaxed grains. Under the effect of fine grain strengthening, the Cu-10Sn-12Ni (C12NS) coating achieved a higher microhardness of approximately 222.9 +/- 5.3 HV0.2. In the electrochemical corrosion test, the increased in the number of grain boundaries significantly reduced the corrosion resistance of the Cu-10Sn-xNi coatings. The Cu-10Sn-6Ni (C6NS) coating exhibited excellent corrosion resistance, with an I-corr of only 1.37 mu A/cm(2). The results of the dry sliding wear test showed that under the influence of the hardness gradient between the hard precipitate phase and the soft matrix of the coating, the C6NS coating achieved satisfactory wear resistance with a specific wear rate of 3.30 x 10(4) mu m(3)/Nm. Meanwhile, due to the good corrosive resistance, the C6NS coating showed the best tribological performance in 3.5 wt% NaCl environment, and the specific wear rate was 1.58 x 10(4) mu m(3)/Nm.
10.1016-j.mtcomm.2024.110407	14	strength; properties; conductivity; electrical; mechanical; cu-; grain; mpa; electrical conductivity; aging; precipitation; phase; mechanical properties; tensile; phases	Cu-12.5Ni-5Sn-xMo (x=0, 0.5, 1.0, 1.5 wt%) alloys were prepared using Spark Plasma Sintering (SPS) technology. The effect of Mo addition on the microstructure and mechanical properties of Cu-12.5Ni-5Sn alloy was investigated. The results indicate that adding trace amounts of Mo significantly refines the grain structure of Cu-12.5Ni-5Sn alloy, attributed to the formation of Mo-rich phases. Mo addition also inhibited the growth of discontinuous precipitation (DP) after aging treatment, reducing the DP volume fraction from approximately 25 % to 6 %. This effect is attributed to the precipitation of micron-sized Mo-rich phases at grain boundaries, which inhibit DP nucleation and growth by occupying gamma-phase nucleation sites and pinning grain boundaries, thus impeding grain boundary diffusion. In addition, the interlamellar spacing of the discontinuous precipitation increases and the growth rate of lamellae decreases with increasing Mo content. Furthermore, an optimized combination of hardness (310 HB) and yield strength (586 MPa) was achieved in the Cu-12.5Ni-5Sn-1.0Mo alloy after aging treatment.
10.1016-j.mtcomm.2024.110513	15	aging; strength; conductivity; electrical conductivity; electrical; mpa; treatment; strengthening; degrees; cu-; cold; precipitation; tensile strength; tensile; iacs	The effect of Mg element on microstructure, strength, conductivity and softening temperature of the Cu-Ni-Fe-P alloy was investigated in details by TEM, EBSD and XRD. The results showed that Cu-0.3Ni-0.3Fe-0.16 P-0.1Mg alloy with high strength and high conductivity was obtained. The tensile strength, microhardness and electrical conductivity of the Cu-Ni-Fe-P-Mg alloy were 692 MPa, 215 HV and 65.2 %IACS, respectively by 90% coldrolling(90 %CR) + aging at 450 degrees C for 4 h + 60 %CR. The microstructure analysis indicated Mg element refined the size of grains and (Ni, Fe)2P precipitation phase thus improving the strength of Cu-Ni-Fe-P alloy. The strengthening contributions for Cu-Ni-Fe-P(-Mg) alloys were mainly the precipitation strengthening and dislocation strengthening. In addition, the Cu-Ni-Fe-P-Mg alloy had an excellent softening temperature, as the Mg element delayed the recrystallization of deformed structures because of inhibiting the coarsening of precipitates.
10.1016-j.mtcomm.2024.110603	1	shape; memory; shape memory; damping; martensite; martensitic; damping capacity; transformation; capacity; strain; superelasticity; temperature; cu-al-mn; shape memory effect; effect	The occurrence of martensitic stabilization shows a strong positive dependence on M-s temperature in Cu-Zn-Al alloys. Compared with Cu-Zn-Al alloys, Cu-Al-Ni alloys have a more excellent resistance to martensitic stabilization. However, whether the occurrence of martensitic stabilization is dependent on M-s temperature in Cu-Al-Ni alloys is still unknown. To clarify this question, we investigated the relationship between SME and M-s temperature in directly-quenched Cu-Al-Ni alloys. Results showed that the positive dependence of martensitic stabilization on M-s temperature indeed existed in directly-quenched Cu-Al-Ni alloys. The Cu-Al-Ni alloys with M-s <= 488 K possess a good resistance to martensitic stabilization. For the directly-quenched Cu-Al-Ni alloys with remarkably higher than 488 K, they cannot obtain SME due to the occurrence of martensitic stabilization after recovery heating at <25 K/s. The original number of vacancies at martensite boundaries (N-vmb) rising with the increment in M-s temperature was responsible for the remarkable lowering in resistance to martensitic stabilization during the process of slow heating. To adjust the original N-vmb in alloys with remarkably high M-s temperature, we changed the M-s temperature through precipitating alpha phase. The precipitation of alpha phase can enrich the matrix with Al and Ni elements and thus decrease the M-s temperature. The reduction in M-s temperature to below similar to 500 K significantly decreased the original N-vmb and improved the resistance to martensitic stabilization during the slow heating process.
10.1016-j.mtcomm.2024.110730	-1		Given the limitation of the precipitation strengthening effect in high strength and high conductivity Cu-Cr alloy, work hardening emerges as a practical and effective means to further enhance its strength . The Cu-0.4 wt%Cr alloy underwent varying degrees of cold rolling between the solution and aging treatments. The results of TEM characterization indicate that plastic deformation enhances precipitation, which occurs earlier than recrystallization in the deformed Cu-0.4 wt%Cr alloy. Thermodynamic calculations indicate that the driving force for precipitation is several orders of magnitude higher than that for recrystallization, while the nucleation barrier for precipitation is several orders of magnitude lower than that for recrystallization. Thus, the delayed recrystallization relative to precipitation theoretically allows for the coexistence of precipitates and deformed microstructures. In the peak aging state, despite the presence of numerous deformed microstructures, conductivity is almost fully restored. After aging for 1 h, the synergistic strengthening effects of precipitation and work hardening result in the yield strength and tensile strength of the sample cold rolled 64 % reaching 384.6 MPa and 422.0 MPa, respectively.
10.1016-j.mtcomm.2024.110787	-1		In this paper, (Ni2B+C)/Cu composites were prepared by hot pressing sintering (HP), and then heat treatment (HT) and multidirectional forging (MDF) were carried out to regulate the amount, size and distribution of reinforced phases. The evolution behavior of local structure and its effect on properties during heat treatment and multidirectional forging were studied. Results show that the Vickers hardness and electrical conductivity of (Ni2B+C)/Cu composite after solid solution, multidirectional forging, and aging treatment can reach 171.1 HV and 46.5 %IACS, respectively, which are increased by 55.3 % and 69.1 % compared with the as-sintered. The tensile strength can reach 355.1 MPa, and the facture elongation is increased to 5.2 % compared with the as- sintered (0.3 %), achieving a transition from brittle fracture to plastic fracture. In addition, the dry friction and wear mechanism of the composite is mainly abrasive wear, while the current-carrying friction and wear mechanism changes from abrasive wear to a coexistence of abrasive wear and oxidation wear. This work provides a new way to improve the properties of (Ni2B+C)/Cu composites.
10.1016-j.mtcomm.2024.110886	14	strength; properties; conductivity; electrical; mechanical; cu-; grain; mpa; electrical conductivity; aging; precipitation; phase; mechanical properties; tensile; phases	The application of cryogenic rolling technology serves to enhance the strength of a material by increasing the density of dislocations and refining the grain size. However, a high density of dislocations can lead to a reduction in its ductility. In this study, cryogenic rolling at low strain followed by subsequent aging treatment at temperatures between 450 and 550 degrees C was employed to introduce deformation twins into C70250 Cu alloys, aiming to balance both strength and electrical conductivity. The microstructural evolution and property changes of the alloy were examined throughout the cryogenic rolling and aging process using SEM, TEM, XRD, and various mechanical and electrical property tests. The results indicate that alloys subjected to cryogenic rolling and aging exhibit significantly improved strength compared to those treated at room temperature. The introduction of twinning through cryogenic rolling significantly enhances the efficiency of dislocation multiplication during rolling. This high dislocation density facilitates the nucleation of precipitated phases during the subsequent aging process, leading to superior mechanical properties. Within the integrated cryogenic rolling and aging treatment, the precipitated phases, dislocations, and twin boundaries collectively exert a synergistic reinforcing effect, resulting in exceptional yield and tensile strengths, reaching up to 685 MPa and 744 MPa, respectively. The findings in this study contribute to the development of novel methods for fabricating high-strength, high-conductivity copper alloys.
10.1016-j.mtcomm.2024.110887	-1		This study investigates the mechanical behavior and deformation property of CuZr/Cu amorphous/crystalline (AC) composites subjected to uniaxial tensile loading. The results reveal significant insights by varying amorphous shell thickness and amorphous alloy composition. Reducing the amorphous shell thickness from 20 & Aring; to 5 & Aring; increases the tensile strength of the composite from 2.715 GPa to 4.668 GPa due to the enhanced AC interface effect. The insertion of crystalline phases in the amorphous matrix induces nucleation zones for the shear bands and dislocations, affecting the plastic flow distribution. The shear strain and residual stress predominantly manifest in the amorphous shell. A thinner amorphous shell induces substantial shear strain in crystalline phases, promoting homogeneous deformation. The dislocations prompt plastic deformation in crystalline phases, altering atomic configurations. The AC interfaces initiate deformation nucleation, generating partial dislocations, stacking faults, and twinning in the tension. Besides, the total dislocation length rises with strain increase and thinner amorphous shell. Moreover, the increase of Cu content in the amorphous CuZr shell leads to increased tensile strength and elastic modulus. The higher Cu content increases the concentration of shear strain regions in the composites. The deformation mechanism is also switched from the dominant shear band to the homogenous deformation with increasing Cu content in the amorphous shell. Finally, the phase change shows that the FCC phase decreases and the amorphous phase gain is less as the percentage of Cu in the amorphous increases.
10.1016-j.mtcomm.2024.111187	6	grain; deformation; strain; strength; dislocation; cu-; tensile; size; ecap; grain size; sfe; ductility; hardening; high; stress	In the present study, tensile behavior and formability of Cu and Cu-Al foils were investigated to understand the interactive effects of the specimen thickness-to-grain size ratio (t/d) and the alloy content. Pure copper (Cu), Cu1.5 wt%Al, and Cu-5wt%Al sheets were cold rolled to a thickness of 350 mu m followed by annealing to obtain foils with different t/d ratios. These foils were deformed in tension at room temperature, while the formability of the foils was analyzed through a miniatured Nakajima setup consisting of three different specimen geometries. The evolution of microstructure and crystallographic texture was studied by using electron backscattered diffraction and bulk X-ray diffraction. The strength, strain hardening rate, and forming-limit strain increased with increasing either the t/d ratio or Al content. The Hall-Petch analysis showed that the foils, in particular the Cu-Al alloys, exhibit a higher strengthening coefficient than those reported for similar alloy(s) in bulk form, signifying the effect of the t/d ratio. Microstructural examination of the interrupted tensile tested samples of a given t/d ratio showed substantial deformation twinning in Cu-Al alloys. Deformation texture analysis revealed the development of alpha-fiber texture i.e., < 110 > ||ND (normal direction) with the strengthening of the brass component ({110}<112 >) when increasing either the t/d ratio or the Al content. In addition, the formation of theta-fiber texture (<100 >||ND) was observed when the strain path changed from uniaxial to biaxial stretching for a given t/d ratio. The higher strain hardening ability, increased twinning fraction, and the strengthening of brass component during deformation are indicative of the effect of stacking fault energy which decreases for Cu with increasing the Al content. The results and analysis suggest that the t/d ratio effect is minimal on the forming ability of low stacking fault energy materials due to the deformation twinning leading to dynamic grain refinement even at lower t/d ratios.
10.1016-j.mtcomm.2024.111196	15	aging; strength; conductivity; electrical conductivity; electrical; mpa; treatment; strengthening; degrees; cu-; cold; precipitation; tensile strength; tensile; iacs	The microstructure, mechanical property and the electrical conductivity of rolled Cu-3Ti alloy samples subjected to various aging treatments were analyzed using an optical microscope, a scanning electron microscope (SEM), a transmission electron microscope (TEM), an electron backscatter diffraction (EBSD), an X-ray diffraction (XRD), a universal testing machine and a conductivity tester. These analyses aim to establish a fundamental relationship between the microstructure and properties of the Cu-3Ti alloy following deformation and aging treatments. The obtained results indicate that the tensile strength of the deformed sample with 50 % of reduction reaches 414 MPa, with an increase of approximate 29.6 % than that of the as-cast sample. The combined effect of 50 % of deformation reduction and this novel three-stage aging treatment demonstrate an obvious strengthening effect, such as the hardness, the yield strength and the ultimate tensile strength increasing by 20.4 %, 36.8 % and 34.1 %, respectively, compared to the solid-solution rolled sample. And the theoretical calculations based on the analysis of mechanical properties closely align with the actual results. On the other hand, the conductivity of the Cu-3Ti alloy decreases as the rolling reduction increases; however, the deficiency regarding the decrease of the conductivity can be effectively alleviated and the electrical conductivity of the Cu-3Ti alloy with a 50 % of rolling reduction increases by 7.17 % after the three-stage aging treatment, achieving an enhanced balance of strength and electrical conductivity for the Cu-3Ti alloy.
10.1016-j.mtcomm.2024.111310	-1		Cu-12Sn-xBi-2Ni (wt%, x = 0, 2, 4, 6) alloy was prepared by conventional casting and its tribological behavior was studied with the aim of developing a non-toxic and environmentally benign self-lubricating alloy. The coefficients of friction (COF) and wear rates of Cu-12Sn-xBi-2Ni alloy were tested. The morphology of the friction surface was observed and the effect of Bi on the subsurface microstructure under friction was analyzed. The results indicate that the average COF of the alloy reduces from 0.49 to 0.20 with the increment of Bi, and the addition of Bi makes the initially increased wear rate of the alloy before it subsequently decreases. The roughness of the friction surface follows a trend similar to the wear rate, and the surface roughness is the lowest when the Bi content reaches 6 wt%. The addition of Bi alters the surface morphology of friction samples and eliminates the surface oxidation products. Bi also diminishes the deformation of the subsurface in the friction samples, resulting in a decrease in the thickness of the nanograin region within the subsurface layer. Hence, Cu-12Sn-6Bi-2Ni alloy exhibits optimal self-lubricating properties and can be expected to serve as a novel non-toxic self-lubricating alloy.
10.1016-j.mtcomm.2024.111328	14	strength; properties; conductivity; electrical; mechanical; cu-; grain; mpa; electrical conductivity; aging; precipitation; phase; mechanical properties; tensile; phases	Cu-Ni-Si alloys are extensively employed across the electronics industry and diverse sectors because of their unparalleled blend of strength, electrical conductivity, and stress relaxation resistance. The Cu-Ni-Si-Co-Mg-(Cr/ Mn) alloy was prepared via the vacuum induction melting process. The effects of Cr and Mn on the microstructure and characteristics of the alloy were examined through transmission electron microscopy, electrical conductivity tests, tensile tests, and stress relaxation tests. The incorporation of Cr and Mn considerably increased the mean precipitate size within the Cu-Ni-Si-Co-Mg alloy, as evident in a comparative analysis with the control sample. For the Cu-Ni-Si-Co-Mg-(Cr/Mn) alloy, (Ni, Co)2Si was the main precipitated phase, with Cr coprecipitating as elemental Cr particles and some Cr particles together with (Ni, Co)2Si particles, whereas Mn existed in the solid solution. To elucidate the effects of Mn and Cr on the precipitated phase in the Cu-Ni-Si-CoMg-(Cr/Mn) alloy, a precipitation kinetics equation was formulated to govern the phase evolution during the aging process. The S curve of the isothermal phase transition kinetics was subsequently plotted. The incorporation of Cr and Mn into the Cu-Ni-Co-Si-Mg-(Cr/Mn) alloy accelerated the nucleation rate of the precipitates. The addition of Mn and Cr to the alloy negligibly affected its tensile strength and yield strength . The tensile strength exhibited a narrow variation range of 763-783 MPa. The incorporation of Mn notably enhanced the stress relaxation resistance of the alloy but slightly reduced its electrical conductivity. In contrast, the addition of Cr had a more modest positive influence on the stress relaxation resistance, yet it clearly increased the electrical conductivity by 11.9 %. Furthermore, the individual effects of Mn and Cr on the stress relaxation resistance properties of these alloys were comprehensively investigated.
10.1016-j.mtcomm.2024.111348	8	hot; deformation; strain; strain rate; dynamic; hot deformation; recrystallization; dynamic recrystallization; flow; rate; flow stress; compression; constitutive; degrees; stress	Isothermal hot compression experiments using an as-cast Cu-Ni-Co-Si alloy were conducted using a Gleeble3800D thermal mechanical simulator in the temperature range of 700-950 degrees C and the strain rate range of 0.01-5 s- 1. Based on the experimental results of the true stress strain curves, the influence of the deformation temperature and strain rate on the hot deformation behavior was analyzed. The Arrhenius constitutive model and the hot working maps were established. Electron backscatter diffraction and transmission electron microscopy were used to analyze the microstructural evolution and dynamic softening mechanism of the alloy during deformation. The results indicated that the softening of the Cu-Ni-Co-Si alloy during hot compression was influenced by discontinuous dynamic recrystallization (DDRX) and twinning mechanisms. The optimal thermal mechanical parameters for hot deformation of the alloy were 900-950 degrees C/0.01-1 s- 1. When the deformation temperature increased from 850 to 950 degrees C, complete dynamic recrystallization almost occurred. As the strain rate increased from 0.1 to 5 s- 1, the proportion of low-angle grain boundaries decreased from 73.2% to 12.1%, the dislocation density inside the deformed grains decreased from 2.14 to 0.66, and the proportion of twin boundaries increased from 6.09 % to 24.2 %. The accumulation of dislocations at the Sigma 3 grain boundaries promoted the occurrence of DDRX. Nanoscale delta-(Ni, Co)2Si precipitated during hot deformation of the Cu-Ni-CoSi alloy, which promoted grain refinement.
10.1016-j.mtcomm.2024.111359	-1		In the present work, a short and energy conservation technology, i.e., vacuum downward continuous casting (VDCC) and drawing deformation are combined to produce high-strength and high electrical conductivity Cu0.31Te alloy. The effect of drawing strain (0 <= 3.66) on microstructure and properties of Cu-0.31Te alloy are investigated. At the initial stage of drawing, incidental dislocation boundaries (IDBs) are responsible for the strengthening of Cu-0.31Te alloy. As the drawing strain increases to 2.85, the density of IDBs gradually increases and the average boundaries of the geometrically necessary boundaries (GNBs) are greatly refined. The GNBs develop into high angle boundaries (HAGB) with misorientations mainly up to 15 degrees-30 degrees. Furtherly increasing the strain to 3.22, the boundaries with misorientations angle up to 30 degrees-60 degrees are generated, which can be attributed to formation of the < 111 > texture //drawing direction. The Cu2Te phase play an important role in strengthening by facilitating the strong lattice rotations of the adjacent matrix areas and promoting the formation of HAGBs. The HAGBs nearby Cu2Te phase also continue to be refined with the increased strain. The fibrous Cu2Te phase has little effect on the electrical conductivity in the longitudinal direction. After VDCC and drawing with the strain of 2.85, the Cu-Te alloy has an ultimate tensile strength (UTS) of 378.5 +/- 3.4 MPa, yield strength (YS) of 352.8 +/- 3.9 MPa, elongation of 2.6 +/- 0.3 % and electrical conductivity of 96.9 +/- 0.5 % IACS. As the strain continues to increase, the tensile strength continues to increase accompanied by reduced elongation and electrical conductivity. At larger strains (2.85 <=epsilon<3.66), grain boundary strengthening by GNBs and dislocation strengthening by IDBs are dominated strengthening mechanisms. This research provides some valuable experimental guidance for manufacture high-strength and high electrical conductivity Cu-Te alloy.
10.1016-j.mtcomm.2024.111421	-1		Strength is one of the crucial properties for conductive Cu wire, which could usually be strengthened by colddrawing. In this study, the relationship between the strength and microstructure of the directionally solidified Cu wires with various drawing strains was quantitatively revealed. During the cold-drawing process, the strength of the Cu wires increased rapidly in the early stages and more gradually in the later stages. Through continuous drawing, the ultimate tensile strength increased from an initial value of 164.5 MPa to 432.8 MPa. Microstructure observations showed that the grain width of the Cu wire continuously refined with increasing drawing strain, along with a gradual rotation of grain orientation from < 001 > to < 111 > , ultimately resulting in a high proportion of < 111 > texture. While the dislocation density showed an initial rise followed by a subsequent decrease. Further quantitative analysis revealed that the grain boundary strengthening, dislocation strengthening and texture strengthening were dominating factors contributing to the significant increase in strength of Cu wire during the early drawing stage. However, the dislocation recovery in the later drawing stage was responsible for the slow increase of strength . Additionally, inspired by the exponential strain-hardening model, a quantitative model for predicting the strength of Cu wire based on the drawing strain was proposed.
10.1016-j.mtcomm.2024.111449	14	strength; properties; conductivity; electrical; mechanical; cu-; grain; mpa; electrical conductivity; aging; precipitation; phase; mechanical properties; tensile; phases	The effect of Nb addition on the microstructure and properties of Cu-3.2Ti alloy was thoroughly investigated using metallographic microscopy, X-ray diffraction, scanning electron microscopy, and transmission electron microscopy. The results indicate that the addition of 0.1 wt% Nb to the Cu-3.2Ti alloy effectively inhibits the formation and growth of discontinuous precipitates without compromising the alloy's peak hardness and electrical conductivity. Nb primarily exists as Nb particles, and Nb particles distributed at grain boundaries can both pin the boundaries and refine grains, as well as occupy nucleation sites for discontinuous precipitation. Meanwhile, Nb particles distributed within the grains can impede the movement of the interface front. The combined effect of these two factors suppresses the formation of discontinuous precipitation. Additionally, Nb atoms dissolved in the Cu matrix induce lattice distortion, facilitating the formation of the (3'-Cu4Ti phase and thereby boosting the conductivity of the Cu-3.2Ti-0.1 Nb alloy during peak aging.
10.1016-j.mtcomm.2024.111457	-1		Metastable immiscible Cu-Fe alloys exhibit a good combination of electrical conductivity and electromagnetic shielding properties. The introduction of element, Ni, can breakthrough the issue of poor solubility between Cu and Fe. In present work, a series of Cu-rich Cu-Ni-Fe alloys was designed and prepared by changing the Ni/Fe atomic ratio, Ni and Fe contents. The comprehensive investigations on the microstructure, existence form of magnetic element, magnetic properties (including saturation magnetization, Ms and coercivity, Hc) and electrical resistivity with the variation of chemical composition were obtained in Cu-rich Cu-Ni-Fe alloys. Further, the relationship between chemical composition-microstructure-magnetic behavior of Cu-rich Cu-Ni-Fe alloys is unveiled. The results showed that the addition of Ni promoted a more uniform distribution of element, Fe, as well as introducing nano-magnetic phases. In the Cu-Ni-Fe alloys with the same Cu content, their electrical resistivity show positively associated with the Ni content. The main factor for affecting Ms is the total amount of ferromagnetic elements. With the increase of Fe content, the absolute value of the variation slope of Ms increases. Meanwhile, under the same Cu content, the Ms was positively correlated with the Fe content, while Hc was negatively correlated with the Fe content. The magnetic properties of the selected alloy should meet the engineering requirements. Thus, it is necessary to rationally allocate the composition and microstructural characteristics to obtain the desired combination of Ms and Hc. Furthermore, the measured results of magnetic force microscopy indicate that the magnetic properties of the alloys show a strong correlation with the morphological evolution, and the addition of Ni enable the value of Hc to decrease through reducing the number of (Fe, Ni)-rich coarse dendrites. This study provides necessary theoretical analysis and experimental evidence for the application of soft-magnetic Cu-rich Cu-Ni-Fe ternary alloys.
10.1016-j.mtcomm.2024.111478	-1		Liquid phase sintering of Cu-30 wt% Co alloys was performed at various temperatures and durations, both in the absence and presence of a 12 T magnetic field. The influence of the magnetic field and sintering temperature on the microstructural evolution and coarsening behavior of Co particles was systematically studied. The results demonstrated that irrespective of the application of the magnetic field, Co particle size increased with prolonged sintering time, and the coarsening kinetics followed the r 3 proportional to t relationship. However, when a magnetic field was applied and the temperature increased, the coarsening of Co particles in the Cu liquid matrix was significantly accelerated. The high magnetic field notably enhanced the interaction and coalescence of Co particles leading to the formation of chain-like structures. This alignment was more pronounced at temperatures below the Curie temperature, where the interaction between magnetic dipoles of Co particles facilitated chain formation. Above the Curie temperature, the reduced magnetism of Co particles weakened this effect. Consequently, the high magnetic field and elevated temperature played a synergistic role in influencing the liquid phase sintering behavior of Cu-30 wt% Co alloys.
10.1016-j.mtcomm.2024.111484	12	thermodynamic; ternary; phase; data; experimental; equilibria; phase equilibria; liquid; binary; experimental data; calculated; phases; literature; model; calphad	The phase equilibria of the Cr-Zr-Ni ternary system were re-assessed using the CALPHAD (CALculation of PHAse Diagrams) method. The calculated results are in agreement with the experimental phase equilibria data reported in the literature, including isothermal sections, vertical sections, and liquidus projections. Based on the thermodynamic descriptions in this work and in the literature, a thermodynamic database for the Cu-Cr-Zr-Ni quaternary system was established. Phase equilibria of the Cu-Cr-Zr-Ni system at 700 and 900 degrees C, with a constant content of 5 at% Zr, were measured using X-ray diffraction (XRD) and scanning electron microscopy with energy dispersive X-ray spectroscopy (SEM/EDS). Overall agreement between predicted phase equilibria and experimental results confirms the accuracy of the established thermodynamic database. Additionally, the reliability of the thermodynamic database was tested in a quaternary cast alloy by comprehensive comparison of their experimentally measured solidified microstructure characteristics with the results of Scheil-Gulliver simulations. This study provides a thermodynamic basis for the design of multi-component copper alloys.
10.1016-j.mtcomm.2025.111539	8	hot; deformation; strain; strain rate; dynamic; hot deformation; recrystallization; dynamic recrystallization; flow; rate; flow stress; compression; constitutive; degrees; stress	Hot deformation tests of Cu-0.3Zr and Cu-0.3Zr-0.2Mg alloys were conducted at 700 degrees C-900 degrees C and 0.003 s(-1) 10 s(-1) strain rates. Based on the experimental results, constitutive equations and hot processing maps for both alloys were established. EBSD analysis revealed the alloys' microstructure evolution behavior during hot deformation. At deformation condition of 0.1 s(-1) strain rate, as the temperature increased from 800 degrees C to 850 degrees C, the predominant texture in Cu-0.3Zr transitioned from {110}< 15 > Goss/Brass texture to {110}< 001 > Goss texture. In contrast, the predominant texture in Cu-0.3Zr-0.2Mg shifted from {110}< 115 > Goss/Brass texture to {110}< 111 > A texture. TEM analysis revealed that during hot deformation, Cu5Zr and CuMg2 precipitates formed in the Cu-0.3Zr-0.2Mg alloy, contributing to grain refinement.
10.1016-j.mtcomm.2025.111616	-1		Cu-12.5Ni-5Sn-xAl alloy with different Al addition amounts was prepared using spark plasma sintering (SPS). The effects of trace Al addition on the microstructure and corrosion behavior of Cu-12.5Ni-5Sn-xAl alloy were studied, and the corrosion mechanism was discussed. The results show that the grain size of the alloy is significantly refined and the alloy is more compact after adding trace Al. The compact density of Cu-12.5Ni-5Sn1.0Al alloy is 102.08 %. As the Al content increases from 0 wt% to 1.0 wt%, the corrosion resistance of Cu12.5Ni-5Sn-xAl alloy gradually improves. The Cu-12.5Ni-5Sn-1.0Al alloy has a lower self-corrosion current density (2.088 x10- 5 A/cm2) and a lower corrosion rate (0.253 mm/a). Compared with Cu-12.5Ni-5Sn alloy without Al, its maximum corrosion depth is reduced by about 44.1 %, and its corrosion resistance is better. The Cu-12.5Ni-5Sn alloy exhibits significant Sn segregation, with Sn preferentially dissolving during the corrosion process. Al improves the compactness and stability of the film by promoting the uniform distribution of Sn. The high impedance observed in the Nyquist plot confirms the generation of a dense oxide layer on the surface of the alloy with the addition of Al. The inner layer of the corrosion product is primarily composed of NiO and SnO, while the outer layer mainly consists of Cu oxides. Additionally, Al participates in the reaction to form Al2O3, which further prevents the erosion of the alloy by corrosive ions.
10.1016-j.mtcomm.2025.111826	14	strength; properties; conductivity; electrical; mechanical; cu-; grain; mpa; electrical conductivity; aging; precipitation; phase; mechanical properties; tensile; phases	It is still a challenge to prepare copper alloys with a combination of high strength, ductility and electrical conductivity. Here, we have developed a layered composite material, CuCrZr/Cu-Al2O3, by leveraging the unique properties of Cu-Cr-Zr system alloys and Al2O3 dispersion-strengthened Cu alloys. This composite is engineered through the sequential stacking of Cu-Cr-Zr alloy layers and Al2O3-dispersed Cu alloy layers, followed by sintering and thermomechanical processing. It shows a superior combination with a yield strength of 620 MPa, a uniform elongation of 7.7 %, and an electrical conductivity of 81.9 % IACS. Remarkably, these properties exceed the predictions made by the rule-of-mixtures model. We have meticulously characterized the microstructures of the composite's components and compared them to their standalone counterparts to understand the mechanisms behind the enhanced properties of the composite.
10.1016-j.mtcomm.2025.111874	14	strength; properties; conductivity; electrical; mechanical; cu-; grain; mpa; electrical conductivity; aging; precipitation; phase; mechanical properties; tensile; phases	The Cu-15Ni-8Sn alloy has attracted considerable attention as a novel copper-based alloy material. The impact of chromium (Cr) addition on the microstructure and properties of the Cu-15Ni-8Sn alloy were investigated by using optical microscopy (OM), scanning electron microscopy (SEM), and transmission electron microscopy (TEM). The results show that the incorporation of Cr reduces the secondary dendrite spacing in as-cast alloys and effectively mitigates dendrite segregation. Additionally, Cr begins to precipitate during the solidification process, forming Cr-rich phases. During the aging process, these Cr phases occupy the nucleation sites of the discontinuous precipitates and impede the movement of their front interfaces, thereby effectively suppressing the formation of discontinuous precipitates. The addition of 0.7 wt% Cr exhibited the most pronounced inhibitory effect, leading to a peak hardness of 357.9 HV, tensile strength of 742.6 MPa, and conductivity of similar to 9.8 % IACS after aging at 450 degrees C for 7 hours.
10.1016-j.mtcomm.2025.112020	-1		Dual-phase alloys (Cu-Fe alloys) exhibit excellent strength by dual-phase strengthening at the interface of harder and softer phases, at the expense of ductility. In an attempt to address this limitation in Cu-Fe alloys, a novel Curich (Cu50Mn30Fe10Co10) compositionally complex alloy (all elements in at%, Cu-CCA) has been developed by merging compositionally complex alloy (CCA) design principles with classical phase separation mechanism. The as-cast Cu-CCA exhibits not only phase separation (alpha(f.c.c)->alpha 1(f.c.c.) + alpha 2(f.c.c)) but also possesses unprecedented strength-ductility (oUTS = 630 MPa, 8 = 36 %) synergy. The occurrence of phase separation into a mixture of two f.c.c. phases is a result of intelligent alloy design whereas excellent strength-ductility synergy is facilitated primarily by hetero deformation induced (HDI) strengthening at the junctions of these separated phases during deformation. Thus, this identical phase separation in newly designed Cu-CCA overcomes the conventional strength-ductility paradigm in as-cast Cu and most of its binary/ternary alloys thereby making it a profound candidate for structural applications.
10.1016-j.mtcomm.2025.112041	-1		Copper alloys are widely used in the field of marine engineering due to their excellent corrosion resistance and mechanical properties. This study investigated the corrosion behavior of a new Cu-19Ni-6Cr-7Mn alloy and a commercial Cu-15Ni-8Sn alloy in a 3.5 % NaCl solution using EIS, XPS and electrochemical test, etc. The results indicate that the new Cu-19Ni-6Cr-7Mn alloy exhibits excellent mechanical properties (978 MPa) and corrosion resistance. The annual average corrosion rate of the Cu-19Ni-6Cr-7Mn alloy is 0.0542 mm/a, which is 62 % lower compared to the Cu-15Ni-8Sn alloy (0.1442 mm/a). The corrosion current density of Cu-19Ni-6Cr-7Mn alloy is 2.23 mu A/cm2, which is lower than that of the commercial Cu-15Ni-8Sn alloy (4.36 mu A/cm2). The corrosion products on the surface of Cu-19Ni-6Cr-7Mn alloy gradually increase with the corrosion time. Corrosion product films containing Cu2O, NiO, Cr2O3 and MnO2 are formed on the surface of Cu-19Ni-6Cr-7Mn alloy. As the corrosion time extends, oxides such as Cr2O3 and MnO2 accumulate increasingly. These oxides can enhance the density and stability of the corrosion film, hindering the transfer of corrosive media to the substrate, which can significantly reduce the corrosion rate of the Cu-19Ni-6Cr-7Mn alloy. The newly developed high strength, high elastic, corrosion-resistant Cu-19Ni-6Cr-7Mn alloy has great potential for application in marine engineering.
10.1016-j.mtcomm.2025.112044	14	strength; properties; conductivity; electrical; mechanical; cu-; grain; mpa; electrical conductivity; aging; precipitation; phase; mechanical properties; tensile; phases	This study investigates the influence of aluminum addition on the mechanical properties and internal structural evolution of Cu-Zr metallic glasses. The addition of Al, up to 20 %, was found to significantly enhance plastic deformation capabilities by reducing shear band localization and promoting a more homogeneous distribution of elastic modulus. The structural heterogeneity reduced from 38 % to 18.6 %, while a decrease in elastic modulus heterogeneity from 27 % to 15.2 % were observed, with increasing Al content. Voronoi polyhedra analysis revealed a substantial increase in < 0 0 12 0 > configurations, with their proportion rising from 2.68 % at 0 % Al content to 8.67 % at 20 % Al content, representing a 224 % increase and highlighting Al's role in enhancing structural uniformity and reducing local stress concentrations. These improvements resulted in enhanced ductility and stability, addressing a critical limitation in the mechanical performance of metallic glasses. This work provides valuable insights into optimizing metallic glass compositions for improved mechanical performance, offering a promising foundation for future materials design aimed at diverse industrial applications.
10.1016-j.mtcomm.2025.112077	-1		Stress relaxation performance is an important mechanical property of high-strength and high-elasticity copper alloys. This work selects Cu-3Ti and Cu-15Ni-8Sn alloys with good application prospects and regulates their mechanical properties through heat treatment. By combining numerical simulation and TEM analysis, stress relaxation studies under tensile and bending loads were conducted at different temperatures. The results show that as the temperature increases, the stress relaxation rate significantly accelerates, and Cu-3Ti alloy has better stress relaxation resistance. Precipitation strengthening is the main mechanism of its stress relaxation performance, while the discontinuous precipitation phase leads to a higher stress relaxation rate in Cu-15Ni-8Sn alloy at high temperature. Compared to the most widely used high-strength and high elasticity Cu-Be alloy, the advantage of stress relaxation performance of Cu-3Ti alloy is more obvious at high temperatures. Meanwhile, in response to the differences in stress relaxation performance under different load forms, considering the service load characteristics of high-strength and high elasticity copper alloy components, a stress relaxation behavior prediction model based on tensile stress relaxation load which can be used to predict the stress relaxation behavior under different load forms was constructed through numerical simulation.
10.1016-j.mtcomm.2025.112108	-1		Electromagnetic shielding materials with high electrical conductivity and permeability effectively attenuate both low and high frequency electromagnetic fields. To optimize the electrical conductivity and permeability of Cu-Fe alloys, a Cu-5wt%Fe alloy was synthesized via mechanical mixing followed by spark plasma sintering (SPS). The influence of annealing temperature and holding time on electrical conductivity, magnetic and mechanical properties was studied. Microstructural and phase characterizations were performed using X-ray diffractometer (XRD), scanning electron microscopy (SEM) and transmission electron microscopy (TEM). The results demonstrate that the electrical conductivity, saturation magnetization, and yield strength of Cu-5wt%Fe alloy after annealing at 500 degrees C for 1 h are increased by 48.05 %, 14.56 %, and 15.50 %, respectively. The enhanced comprehensive properties of the Cu-5wt%Fe alloy are primarily attributed to the precipitation of submicronsized and nano-sized ferromagnetic alpha-Fe phases during annealing. This enhancement benefits the improved electromagnetic shielding efficiency of Cu-5wt%Fe alloy, thereby expanding the potential applications in electromagnetic shielding field.
10.1016-j.mtcomm.2025.112144	-1		In this study, Cu-3Ti and Cu-3Ti-0.5Mg-0.5Sn alloys were subjected to solid solution treatment, 60 % cold rolling, and finally aging at 380 degrees C, 450 degrees C, and 500 degrees C, in order to investigate the impact of Mg and Sn addition on the microstructure and properties of Cu-3Ti alloys. The microstructure, mechanical properties, and electrical conductivities of the Cu-3Ti-0.5Mg-0.5Sn alloy in any state were analyzed in detail. The results revealed that the hardness, tensile strength, and electrical conductivity of the Cu-3Ti-0.5Mg-0.5Sn alloy under peak aging were 337 HV, 925 MPa, and 16.7 %IACS, respectively. The addition of Mg and Sn refined the grain size and enhanced the strength of the Cu-3Ti alloy. Besides, Ti and Sn elements combining with Cu attributed to the formation of CuSn3Ti5 phase, decreased the Ti content dissolved in the Cu matrix, and improved the electrical conductivity of Cu-3Ti alloy. The hardness and conductivity of the cold-rolled Cu-3Ti-0.5 Mg-0.5 Sn alloy were 24 % and 55 % higher than those of the Cu-3Ti alloy, respectively.
10.1016-j.mtcomm.2025.112270	-1		To reveal the mechanism of nano-twin in the plastic deformation process of Cu-Ag alloys, molecular dynamics simulations were used to study the tensile deformation behavior of nanotwinned Cu-7.8 wt% Ag alloy with different nano-scaled twin lamellae thickness. The results indicated that the thickness of twin lamellae played an important role in the strength and the ability to form secondary twins of Cu-7.8 wt% Ag alloy. The plastic deformation of this alloy was dominated by Shockley incomplete dislocations. The twin boundaries hindered the movement of dislocations and the propagation of stacking faults. The plastic deformation mainly occured between the twin lamellaes. The smaller the thickness of twin lamellae, the greater the obstruction of dislocation movement and the more obvious the strengthening effect. When the thickness of twin lamellae was less than 15.22 nm, it was difficult to form secondary twins. The twin boundaries absorbed dislocations while hindering which, with good tensile mechanical stability during the plastic deformation This study investigated the stability and dislocation absorption capacity of twin boundaries during plastic deformation, providing new ideas and methods for the development of high-strength and high-ductility nano-twinned metallic materials.
10.1016-j.mtcomm.2025.112302	14	strength; properties; conductivity; electrical; mechanical; cu-; grain; mpa; electrical conductivity; aging; precipitation; phase; mechanical properties; tensile; phases	This study investigates the effects of dual-stage rolling and double aging on the microstructural evolution and performance of Cu-Ni-P alloys, maintaining a total rolling reduction of 75 %. Results show that after two-stage rolling and aging, the alloy achieves optimal performance: 66.1 %IACS electrical conductivity, 213.7 HV hardness, 630 MPa ultimate tensile strength, and 616 MPa yield strength . Cold rolling promotes extensive precipitation of Ni and P within the Cu matrix, forming phases like Ni3P, Ni12P5, and Ni2P, enhancing both electrical conductivity and strength . Dual-stage rolling further refines the grain size from 3.3 mu m to 2.2 mu m, enhancing grain boundary strengthening. The study found that dislocation strengthening and aging strengthening contribute 30 % and 48 %, respectively, to the total yield strength . This work provides experimental evidence for optimizing thermomechanical treatments of Cu-Ni-P alloys, supporting performance improvements in industrial applications.
10.1016-j.mtcomm.2025.112398	-1		This study investigated the effectiveness of Fe-based metallic glass particles as a reinforcing agent in Cu-based composite coating fabricated using cold spray technology. The cold spray process was conducted at 600 degrees C and 5 MPa. The influence of Fe-based metallic glass content on coating thickness, microstructure, porosity, hardness and shear strength was systematically analyzed. Scanning electron microscopy was used to examine the coating thickness, microstructure and porosity. The microhardness was measured using a microhardness tester, and shear strength was assessed via the ear shear test. The results revealed that the addition of Fe-based metallic glass particles significantly influenced the performance of the coatings. As the mass fraction of Fe-based metallic glass particles increased, the coating thickness and porosity decreased, while microhardness and shear strength improved. Specifically, at 35 % Fe-based metallic glass content, the coating thickness sharply decreased from 355.1 f 12.2 mu m (pure Cu) to 152.8 f 10.7 mu m, while porosity was reduced from 0.58 f 0.02 % to 0.14 f 0.01 %. Meanwhile, the microhardness increased from 157.1 f 1.7 HV (pure Cu) to 177.4 f 1.1 HV, and the shear strength dramatically improved from 37.1 f 1.6 MPa to 114.8 f 4.3 MPa. These findings underscore the critical role of Fe-based metallic glass particles as a reinforcing phase, significantly enhancing the density and mechanical properties of Cu-based composite coatings.
10.1016-j.mtcomm.2025.112549	10	composites; nanoparticles; strength; matrix; high; strengthening; particles; conductivity; composite; electrical; mpa; sintering; ods; grains; mechanical	Y2O3 dispersion-strengthened copper alloy prepared by mechanical alloying (MA) exhibits a high potential to be used as heat-sink materials in the fusion reactor. However, the feasibility of mass-production of the alloy by MA is still suspicious due to the low efficiency and the introduction of impurity elements. In this work, we prepared Y2O3 dispersion-strengthened copper alloy by spray drying, a method suitable for large-scale production with almost no introduction of impurities. Microstructural investigations found that high-density Y2O3 nanoparticles with the size of similar to 9 nm are successfully introduced into the copper matrix by spray drying, which greatly refines the grain and inhibits the recrystallization behavior of the alloy. Moreover, most Y2O3 nanoparticles share a coherent interface with the matrix, and as the Y2O3 particles grow, the coherent interfaces transform into semi-coherent interfaces, with an orientation relationship of (11-1) (Cu)//(422)(Y2O3). The introduction of Y2O3 nano-particles greatly enhances the strength of the copper matrix by inhibiting the moving of the dislocations and grain boundaries, and a good combination of hardness (114 HV), strength (326.5 MPa), ductility (8.5 %) and electrical conductivity (85.3 %IACS) was achieved in the Cu-2Y(2)O(3) (wt%) alloy. This work proves the feasibility of introducing nano-scale Y2O3 particles into the copper matrix by spray drying, however, the experimental parameters need to be carefully controlled to prevent agglomeration of Y2O3 dispersoids. Large-scale production of ODS-Cu alloys for the fusion reactor may be realized through spray drying in the future.
10.1016-j.mtcomm.2025.112561	2	corrosion; surface; film; electrochemical; films; spectroscopy; layer; current; solution; potential; resistance; composition; x-ray; ions; showed	The mechanism of passivation breaking by anaerobic sulfate-reducing bacteria (SRB) on passivated film of copper alloy was investigated in this article. The results confirm that under biogenic sulfide conditions, the dense passivation film composed of copper-oxide with high-protective ability on the surface of copper substrate gradually evolves into loose and porous copper-sulfide film with less-protective ability. This Cu2S film is more easily penetrated by corrosive anions and further accelerates the pitting of the copper alloy substrate. The Point Defect Model (PDM) for copper alloys in SRB-containing environment was established to explain the pitting process of passivation films under S2- corrosion, which describes how sulfur ions occupy oxygen vacancies resulting in a shift from Cu-O to Cu-S in passivation film. Meanwhile, the PDM quantifies the pitting process of S2on passivated film by calculating the resistance, capacitance, semiconductor properties and diffusion coefficient within the passivated film: the adsorbed S2- prevent or retard the re-passivation of the copper alloys through hindering the attachment of O atoms. The relationship between passivation film structure, electrical properties, semiconductor properties and its stability to corrosion resistance was analyzed.
10.1016-j.mtcomm.2025.112706	-1		The objective of the current experimental effort is to identify an economical way to improve the mechanical strength, electrical conductivity, and interface adhesion of copper/graphite composite for electrical-mechanical applications. This study presents the graphite/Cu (Cu-Gr)-composite with an effect of Cu granule (Gn) and Cu coating of graphite particles. Strong cohesion between the unmelted Cu granules and the Cu matrix results in a composite structure that is more stable and effective. The wettability and diffusion between Cu and graphite is greatly enhanced by the metallization graphite surface. The refined Cu granule surface is covered with a convoluted coating of Cu powder created via control mechanical alloying (MA). Superior surface integrity, high interfacial adhesion, dispersion homogeneity, and an ordered composite structure might be generated by the combination of the previously outlined findings. The study figures out that the highest values of density, hardness, electrical conductivity, compressive strength, and flexural strength for 10 % Cu granules in Cu-10Gr-composite, 1.46, 10.7, 13.68, 22.64, and 15.55 %, higher than those of Cu-10Gr composite, respectively.
10.1016-j.mtcomm.2025.112952	14	strength; properties; conductivity; electrical; mechanical; cu-; grain; mpa; electrical conductivity; aging; precipitation; phase; mechanical properties; tensile; phases	Differential scanning calorimetry (DSC) was employed to determine the homogenization conditions for Cu-12Ni-8Sn-xMn alloys with varying Mn contents (x = 0, 8, 12 wt%). The microstructures of as-cast and homogenized Cu-12Ni-8Sn-xMn alloys, as well as their aged microstructures, were characterized using scanning electron microscopy (SEM). Phase compositions after aging were analyzed by X-ray diffraction (XRD), and the relationship between phase transformation processes, microstructural evolution, and mechanical properties was investigated through mechanical testing. Results indicate that increasing Mn content promotes the formation of (Ni,Cu, Mn)3Sn phases in the as-cast structure, replacing the original (Cu,Ni)3Sn phase. For the Cu-12Ni-8Sn alloy, strengthening primarily arises from spinodal decomposition. However, at Mn levels of 8-12 wt%, the alloy exhibits concurrent enhancement in both mechanical properties and overaging resistance, with the strengthening mechanism transitioning to precipitation hardening dominated by MnNi2Sn phases. This transition is accompanied by a substantial refinement of discontinuous precipitation (DP) interlamellar spacing, decreasing from submicron-scale in Cu-12Ni-8Sn alloy to nanoscale. While elevated aging temperatures increase the DP fraction and enhance mechanical properties, excessive temperatures coarsen the interlamellar spacing, ultimately degrading alloy performance. At 12 wt% Mn, DP nucleation shifts from grain boundaries to both grain boundaries and interiors, refining grain structure and further improving mechanical properties, albeit with a slight reduction in overaging resistance.
10.1016-j.mtcomm.2025.113074	2	corrosion; surface; film; electrochemical; films; spectroscopy; layer; current; solution; potential; resistance; composition; x-ray; ions; showed	The current research aims to investigate both electrochemically and computationally how four halide ions (F-, Cl-, Br-, and I-) affect the corrosion of copper (Cu) in a borate solution with a pH of 10.4. Cyclic voltammetry (CV) results indicate that I- is the most aggressive halide ion, significantly facilitating Cu corrosion in the borate buffer. Potentiodynamic polarization (PDP) tests showed a linear increase in the corrosion current density (Icorr) of the Cu surface as the concentration of each halide ion increased. This increase was particularly pronounced in the presence of I-, which indicated it as the most aggressive ion regarding Cu corrosion. The Icorr value reached 4.34 x 10-degrees A/cm2 and the corrosion rate (CR) was measured at 5.44 mm/year in the presence of I-, further supporting the findings from the CV analysis.Additionally, the breakdown potential (Eb) shifted to more negative values with increasing halide ion concentrations, particularly in the presence of I-, demonstrating a greater capacity of I- to induce and promote corrosion on the Cu surface. Electrochemical impedance spectroscopy (EIS) data showed a significant decrease in charge transfer resistance (Rt) and an increase in double layer capacitance (Qd) with higher concentrations of halide ions. This decrease was most pronounced with I-, where Rt decreased from 8.52 to 3.98 Omega & sdot;cm2 and Qd changed from 177.0 to 36.9 F & sdot;cm-2 & sdot;s 1 -. Scanning electron microscopic (SEM) studies indicated corrosive behavior of of I- on Cu surface. These electrochemical results were further supported by computational quantum chemical analysis and Monte Carlo simulations, which indicated stronger interactions between I- and the Cu surface.
10.1016-j.mtcomm.2025.113126	-1		Based on the traditional liquid-solid composite casting method, copper/steel bimetallic samples were prepared by electromagnetic stirring (EMS), and the effects of electromagnetic stirring current on the microstructure, mechanical properties and wear property of copper/steel bimetal were studied. The results showed that EMS was benefical for grain refinement. The structure of the alpha-Cu phase without EMS was all dendrites, as the stirring current increased, the alpha-Cu phase gradually changed to near-spherical crystals, and the average grain size of copper/steel bimetallic copper layer decreases from 517.6 mu m to 54.7 mu m. When the stirring current was 300 A, the interdiffusion distance of Cu and Fe atoms reached 9.4 mu m, the interfacial shear strength reached to 217 MPa, which was increased by 36.5 % compared with that without EMS, the average friction coefficient of the copper layer decreased to 0.216, and the wear rate was reduced to 1.499 x 10-7mm3/(N.m), which was reduced by 26.7 % compared with that without EMS. Additionally, the wear mechanism changed from delamination wear to slight abrasive wear and adhesive wear.
10.1016-j.mtcomm.2025.113132	-1		Functional gradient materials in the regulation of gradient distribution of components through mathematical functions is conducive to the achievement of performance-oriented design. This study adopted molecular dynamics simulation as the research method. The Cu-Ni alloy was selected as the object, and nine power-law function gradient models were constructed. Tensile and nanoindentation experiments were conducted at five characteristic temperatures: extremely low temperature (77 K), low temperature (220 K), normal temperature (300 K), high temperature (420 K), and extremely high temperature (600 K). The results of the study indicate that: The primary factors influencing the performance are the nickel content and the gradient distribution.An increase in the copper content will reduce the yield stress and hardness, but enhance plasticity. It is evident that the comprehensive mechanical properties attain an optimal level at a temperature of 77 K, accompanied by a severe dislocation accumulation phenomenon. An increase in temperature results in a decrease in Young's modulus, though this effect is relatively minor in terms of its influence on indentation behaviour. Dislocation evolution is jointly regulated by loading conditions and element gradients. The research advanced our understanding of the evolution of the microstructure of Cu-Ni alloys, providing a theoretical foundation for the design of FGM in extreme environments.
10.1016-j.mtcomm.2025.113267	6	grain; deformation; strain; strength; dislocation; cu-; tensile; size; ecap; grain size; sfe; ductility; hardening; high; stress	Low-cycle fatigue (LCF) tests were performed at ambient temperature on annealed single-phase Cu-30 wt% Zn (70/30 brass) at strain amplitudes of 0.4 %, 0.7 %, 1.0 %, and 1.2 % to investigate the effect of strain amplitude on the cyclic stress response. The cyclic stress response exhibits primary hardening, softening, and secondary hardening. The primary hardening and softening increases, while the secondary hardening decreases with increasing strain amplitude. Internal stresses determined from stress-strain hysteresis loops show that back-stress hardening and softening dominate the primary hardening and softening, whereas friction stress is almost constant, leading to Masing behavior. Electron backscatter diffraction (EBSD) analysis revealed that Kernel Average Misorientation (KAM) and low-angle grain boundary (LAGB) fraction increase with increasing strain amplitude, indicating an increase in geometrically necessary dislocation (GND) density and recovery of dislocation substructure with increasing strain amplitude. The recovered substructure determined by softening of back stress reveals the formation of planar slip bands, and the slip band intersection increases with increasing strain amplitude, indicating that Cu-Zn 70/30 is a purely planar slip alloy. During secondary hardening, friction stress increases, and unrecovered corduroy substructure forms. The back stress components were determined based on a modified Chaboche model for different strain amplitudes to calculate the intergranular and intragranular back stresses evolution with increasing cycles and increasing strain amplitudes, and correlated with microstructural evolution. There is competition between the evolution of intergranular and intragranular back stress due to heterogeneous dislocation distributions during cyclic softening.
10.1016-j.mtcomm.2025.113316	-1		In this study, the formation, evolution, hardening and penetration behaviors of the copper-based jets were investigated based on SEM, EBSD, XRD, TEM techniques and finite element simulation methods. The results show that, compared with the penetration depth and hardness of the pure copper jets, the penetration depth of the Cu-Nd alloy jets has increased by approximately 22.2 %, and the hardness has increased by approximately 25.5 %. The increase in the jet penetration depth of the Cu-Nd alloy is mainly related to the fact that the addition of rare earth Nd element can simultaneously enhance the plasticity and strength of the alloy, and Nd element may react with O and S elements to release chemical energy. The hardening mechanisms of the Cu-Nd alloy jets mainly include: dispersion strengthening, grain refinement strengthening, dislocation strengthening and twinning strengthening.
10.1016-j.mtcomm.2025.113394	14	strength; properties; conductivity; electrical; mechanical; cu-; grain; mpa; electrical conductivity; aging; precipitation; phase; mechanical properties; tensile; phases	The broader applicability of Cu-15Ni-8Sn alloy produced through conventional casting route is restricted due to its limited ductility and electrical conductivity. This study explores the utilisation of pressure-less sintering in conjunction with forging and subsequent annealing as a means to address the aforementioned limitations. A systematic investigation was carried out to explore the correlation between processing, structure and resulting properties of the powder metallurgy (PM) processed Cu-Ni-Sn alloy. Microstructural tuning accomplished via post-sintering plastic deformation and subsequent heat treatment led to a significant reduction in porosity and grain size, thereby resulting in simultaneous enhancement in relative density, tensile strength and ductility of the PM alloy. Moreover, as compared to the as cast alloy, the processing strategy employed in this study resulted in a remarkable enhancement of approximately 35 % in yield strength, more than a twofold increase in ductility and an improvement of around 32 % in electrical conductivity. The integrated PM processing route adopted in this work presents a scalable solution for the industrial production of high-performance Cu-Ni-Sn alloys, offering a remarkable blend of physical and mechanical properties.
10.1016-j.mtcomm.2025.113496	-1		The vapor phase dealloying (VPD) process is a recyclable method for synthesizing nanoporous metals without producing chemical waste, such as nanoporous Cu (NPC) from Cu-Zn precursor alloys. However, a systematic study utilizing the VPD method to synthesize bimetallic nanoporous materials from a ternary precursor system is absent. In this study, nanoporous copper-silver (NPCS) synthesized from Cu-Ag-Zn precursor alloy was chosen to explore the effect of an additional noble metal on the kinetic analysis and mechanical properties via the VPD process. The results indicate that silver suppresses the diffusion and rearrangement of the remaining atoms during VPD. The ligament size of the NPCS is smaller than that of the NPC under the same VPD conditions, while increasing the energy absorption capacity of NPCSs to 75.4 MJ/cm3. Moreover, the growth of bimetallic ligaments involves forming an intermediate phase. Through different VPD times and temperatures, the calculated activation energy for ligament growth was between 1.3 eV and 1.57 eV, suggesting that the formation of the bimetallic ligament is probably dominated by grain boundary diffusion or interphase boundary diffusion.
10.1016-j.mtcomm.2025.113671	-1		The galvanic corrosion behaviors of B30 copper alloy and TA1 titanium alloy in a 3.5 % NaCl solution were examined using electrochemical noise (EN), scanning electron microscopy (SEM), energy dispersive spectroscopy (EDS), and X-ray photoelectron spectroscopy (XPS). At an area ratio (STA1:SB30) of 1:1, TA1 acts as the cathode, while B30 acts as the anode. A polarity shift was observed at the area ratio of 1:3, where TA1 acts as the anode and B30 acts as the cathode. At an area ratio of 1:5, galvanic corrosion occurred in four distinct stages. At the area ratio of 1:3, the TA1/B30 system exhibited enhanced noise resistance (Rn) and spectral noise resistance (Rsn), alongside localized corrosion and mixed corrosion of uniform and localized corrosion. In contrast, at the area ratios of 1:1 and 1:5, the corrosion type was localized corrosion. The corrosion products of B30 exhibited a bi-layer structure, comprising an inner layer and an outer layer. The corrosion products of TA1 primarily consisted of TiO2, with minor Ti2O3.
10.1016-j.mtcomm.2025.113815	14	strength; properties; conductivity; electrical; mechanical; cu-; grain; mpa; electrical conductivity; aging; precipitation; phase; mechanical properties; tensile; phases	Oxygen-free copper is widely utilized in high-end electronic devices, necessitating the synergistic optimization of high conductivity and softening resistance. This study innovatively introduces trace amounts of rare earth Sc (in ppm) to regulate the microstructure and properties of phosphorus-containing oxygen-free copper. The results demonstrate that Sc reacts with P to form a cubic-structured ScP precipitate, which reduces the solid solubility of P in the copper matrix and thereby enhances electrical conductivity. Upon annealing at 560 degrees C, ScP transforms into an orthorhombic-structured Sc3P phase, while Sc segregates at grain boundaries to form Cu2Sc intermetallic compounds. These synergistic precipitates effectively pin grain boundaries and dislocations, thereby inhibiting recrystallization and softening. This mechanism enables the simultaneous enhancement of conductivity and softening temperature, providing a novel strategy for the development of high-performance copper alloys.
10.1016-j.mtcomm.2025.113849	14	strength; properties; conductivity; electrical; mechanical; cu-; grain; mpa; electrical conductivity; aging; precipitation; phase; mechanical properties; tensile; phases	This present work investigates the microstructural evolution and defect dynamics of bulk porous Cu under proton irradiation. Three-dimensionally interconnected porous copper with a porosity of 71.3 % was synthesized through the chemical dealloying of the Cu30Fe70 precursor alloy. Proton irradiation experiments were conducted at 140 key with a dose of 1 x 1017 ions/cm2, to simulate high-energy space proton radiation. The results show that proton irradiation induces significant defect evolution: spherical defects were formed at the edges of the ligaments, and meanwhile, the defect density surged from 1.128 x 10 1 1 cm-2 to 2.166 x 10 1 2 cm-2. Lattice distortions and partial amorphization were observed near ligament surfaces, attributed to collision cascades and thermal peak effects. Grain boundaries act as effective defect sinks, particularly high-angle boundaries, which enhance defect recovery by providing diffusion pathways. This present work provides insights into leveraging porous architectures and grain boundary engineering to enhance radiation tolerance.
10.1016-j.mtcomm.2025.113917	14	strength; properties; conductivity; electrical; mechanical; cu-; grain; mpa; electrical conductivity; aging; precipitation; phase; mechanical properties; tensile; phases	The friction and wear properties of 3.60 wt% Cu-304 L stainless steel are crucial for its engineering applications. However, existing research has been limited to studying macroscopic wear resistance, providing insufficient insight into atomic-scale behaviors and mechanisms. its a This study aims to clarify the wear mechanisms of 3.60 wt% Cu-304 L stainless steel by employing a multiscale methodology. This approach combines the analysis of the 304 L microstructure with molecular dynamics (MD) simulations, complemented by macro-scale tribological experiments and MD simulations. Experimental results indicate that increasing the load from 5 N to 15 N leads to non-monotonic trends in the coefficient of friction (COF), fine grain fraction, and martensite content, with an initial increase followed by a decrease. In contrast, the wear volume consistently increases. Notably, abrasive wear is predominant at 5 N, but transitions to adhesive wear dominance at 15 N, driven by severe plastic deformation and surface adhesion. MD simulations suggest that as the indentation depth increases, there is a shift from surface wear to volumetric wear, accompanied by an increase in wear-induced atoms and internal defects. As indentation cycles progress, both frictional and normal forces initially decrease and then exhibit periodic fluctuations, reflecting the evolution of surface topography and interfacial interactions. This integrated multi-scale analysis connects macroscopic wear phenomena with atomic-level mechanisms, providing essential insights for the design of high-performance antimicrobial stainless steels with improved wear resistance.
10.1016-j.mtcomm.2025.113982	2	corrosion; surface; film; electrochemical; films; spectroscopy; layer; current; solution; potential; resistance; composition; x-ray; ions; showed	The effect of elemental segregation on the corrosion behavior of five 70/30 Cu-Ni alloys was investigated. Significant banded segregation of Ni was observed along the drawing direction. The statistical segregation degree of Ni (SNi) implies the uniformity of Ni distribution. The E sample with the smallest SNi value (SNi = 0.0136, Rp = 3623 Omega & sdot;cm2) exhibits better corrosion resistance than the A sample with the highest SNi value (SNi = 0.0399, Rp = 1968 Omega & sdot;cm2). The combination of theoretical calculations and multi-scale characterization provided key evidence: (1) DFT calculations revealed that Ni-rich/poor regions had different adsorption effects on Cl-, explaining the spatial non-uniformity of corrosion reaction. SEM and WLI further confirmed the uneven distribution of corrosion products for samples with high segregation. (2) XPS and XRD analyses indicated that Ni2+ doping optimized the chemical environment of Cu sites in Cu2(OH)3Cl, as evidenced by improved structural order (Cu LMM peak width decreased by 22 %) and enhanced electron density (Cu 2p3/2 binding energy shifted negatively by 1.4 eV). This effect enabled E with the smallest SNi value to form a dense barrier layer containing more NiParatacamite. EIS showed that the resistance of corrosion products (Rf) for E increased by 47 % compared to A. This study establishes SNi as a quantifiable index to guide the industrial production of copper-nickel alloys for marine applications.
10.1016-j.mtcomm.2025.114088	14	strength; properties; conductivity; electrical; mechanical; cu-; grain; mpa; electrical conductivity; aging; precipitation; phase; mechanical properties; tensile; phases	The effects of cold deformation on the aging precipitation behavior and comprehensive properties of a Cu-15Ni8Sn-0.3Fe-0.3Er alloy were systematically investigated. The results indicate that as the deformation amount increases, the hardness, tensile strength, and electrical conductivity of the alloy are improved, while the peak aging time is significantly shortened. After 96 % cold rolling deformation and aging at 400 degrees C for 0.5 h, the ultimate tensile strength of the alloy reaches 1454.9 MPa. The enhancement in performance is primarily attributed to the high density of dislocations introduced by cold deformation and its promoting effect on the precipitation of DO22 ordered phases. Analysis of the strengthening mechanisms reveals that precipitation strengthening and dislocation strengthening are the main contributors to the improved strength of the alloy. Furthermore, analysis based on the Avrami kinetic equation demonstrates that increasing the cold deformation significantly promotes the nucleation and growth kinetics of discontinuous precipitation, resulting in an increased precipitation rate and a greater number of nucleation sites.
10.1016-j.mtphys.2020.100311	-1		High power factor and low thermal conductivity are imperative to maximize the energy conversion efficiency of thermoelectric materials. Constantan (Cu-Ni alloy), a widely-used material for thermocouples, has higher power factor (similar to 12000 mu Wm(-1) K-2 at 950 K) [Mao et al 2015] than the classic Bi2Te3-based thermoelectric materials (similar to 4500 mu W m(-1) K-2 at 300 K) [Poudel et al 2008]. However, the high thermal conductivity restricts its thermoelectric performance. In this work, we demonstrate that, the thermal conductivity of Cu-Ni alloy can be effectively reduced from 48.1 to 9.6 W m(-1) K-1 at 873 K by introducing carbon nanotubes (CNTs), and the thermoelectric performance is remarkably improved with the figure of merit (zT) being up to 0.41, an enhancement of about 141% over the pristine CueNi alloy. Negative correlation between the total thermal conductivity of hybrid composite and the specific surface area of CNTs is further identified. The thermal conductivity suppression mechanism is ascribed to the introduction of both porous structures and carbon-nanotube-metal interfaces. Our studies provide a promising and general strategy to enhance the thermoelectric properties of materials with high thermal conductivity.
10.1016-j.mtphys.2020.100332	-1		Cu-Ni-Mn based alloys have long been considered as potential thermoelectric materials because of their Seebeck effect and large power factor. In this study, bulk Cu-Ni-Mn based alloys with nanostructures were prepared via melting and cryorolling, and their thermoelectric and mechanical properties were analyzed. A large number of nanotwins and nanoprecipitates were observed in the prepared alloys using transmission electron microscopy. These observations indicate that the bulk Cu-Ni-Mn alloys with nanostructures can be successfully prepared using conventional melting-solidification-rolling technology. The Cu-Ni-Mn alloy containing nanotwins exhibits a promising Seebeck coefficient of similar to 72.8 mu VK-1 and power factor of similar to 11000 mu Wm(-1)K(-2) at 1073 K, and thereby, a high output power density. The bulk Zr-doped Cu-Ni-Mn alloy containing nanoprecipitates and nanotwins exhibits a lower thermal conductivity of similar to 32.9Wm(-1)K(-1) and a 37.5% higher ZT of similar to 0.22 at 773 K. Enhanced mechanical properties make the Cu-Ni-Mn based alloys a promising candidate for thermoelectric application. Our discovery provides a promising strategy to improve the thermoelectric and mechanical properties of materials with high thermal conductivity through the introduction of nanotwins and nanoprecipitates.
10.1016-j.mtphys.2024.101502	12	thermodynamic; ternary; phase; data; experimental; equilibria; phase equilibria; liquid; binary; experimental data; calculated; phases; literature; model; calphad	Thermal conductivity is one of the important thermophysical properties for describing the ability of a material to transfer heat. The thermal conductivities and microstructures of Cu-Ag, Cu-Cr and Cu-Zr binary alloys were experimentally investigated. 11 equilibrated binary alloys were designed and prepared annealed at 600 degrees C for 60 days. Their phase equilibria and compositions were analyzed by scanning electron microscopy with energy dispersive X-ray spectrometry (SEM/EDS), and the thermal diffusivities at 20, 100, 200 and 300 degrees C and the densities at room temperature were measured by laser flash analysis (LFA) method and Archimedes method, respectively. The heat capacities of alloys at different temperatures were calculated through the thermodynamic database, and then the experimental thermal conductivities of each alloys were obtained by the specific conversion equation. Based on the experimental data from the literature and present work, the thermal conductivities of pure elements, the solid solution phases, the stoichiometric compounds and the two-phase regions were evaluated by the CALPHAD (CALculation of PHAse Diagrams) approach . A set of self-consistent thermal conductivity parameters for description of the Cu-Ag-Cr-Zr system was obtained. Comprehensive comparisons between the calculated and experimental results show that the experimental thermal conductivities were satisfactorily accounted for by the present modeling. The present research results can provide important thermal conductivity information for designing new copper alloys and enrich the thermophysical database of copper alloys.
10.1016-j.nanoen.2018.04.058	-1		Copper sulfide has received wide attention as a potential thermoelectric material with high performance and abundant resource. While the liquid-like Cu ions play an important role for the low kappa(L) and high ZT values, grain-boundary engineering is needed to further enhance the phonon scattering and the thermal stability of Cu2-xS. Here, we introduced the 3D graphene heterointerface into the Cu2-xS matrix by a facile technique combining mechanical alloying (MA) and spark plasma sintering (SPS). A significant ZT enhancement was realized with the highest ZT up to 1.56 and a high power factor of 1197 mu Wm(-1) K-2 at 873 K in the sample with 0.75 wt% graphene. Additionally, the composite showed excellent reproducibility of PF after five cycles testing from room temperature to 873 K, which confirmed the practical application potentiality of this composite.
10.1016-j.nanoen.2023.108999	-1		In order to improve the scale inhibition of copper-based alloys, a novel method is proposed by the synergistic action of triboelectric nanogenerator and copper-based alloy. A triboelectric nanogenerator (TENG) based on copper-based alloy material embedded in polytetrafluoroethylene (PTFE) was constructed, and a scale inhibition structure of coupling the (solid-liquid) triboelectric nanogenerator and the copper-based alloy was designed. Additionally, the alloy scale inhibition device was constructed by utilizing alloys as the scale inhibition element, and the synergistic scale inhibition device was developed by utilizing a coupled structure. Power generation performance tests were conducted for both scale inhibition elements, and scale inhibition effectiveness tests were conducted for both synergistic scale inhibition devices. Measurement results show that the power generation performance of the synergistic scale inhibition element is significantly higher than that of the alloy scale inhibition element. This indicates that the addition of solid-liquid TENG can greatly increase the surface potential of the alloy scale inhibition element. The enhancement of the scale inhibition performance of the alloy scale in-hibition element by solid-liquid TENG is primarily due to this principle. The scale inhibition performance experiment measurement results show that the synergistic scale inhibition effect of solid-liquid triboelectric nanogenerator and copper-based alloy can be realized. The remaining calcium ion concentration in the water treated by the coupling structure is higher than that in the water treated by the copper-based alloy. The scale inhibition rate of copper-based alloy embedded in the solid-liquid triboelectric nanogenerator is significantly increased. Therefore, the scale inhibition performance of copper-based alloy embedded in triboelectric nano-generators can be improved significantly.
10.1016-j.nima.2021.165291	-1		Current investigations into neutrinoless double beta decay and the direct detection of dark matter require increasingly sensitive detector systems that demand ultra-low background materials. These requirements have previously been attained using ultra-radiopure electroformed (EF) copper. However, pure copper possesses high ductility and relatively low strength, which necessitates the need for large amounts of material and extra care during fabrication to help minimize galling and mechanical failure. We investigate an alloying alternative to pure EF copper by examining low wt% copper chrome (Cu?Cr) solid solution alloys, with inquiries into alloy hardness, strength, and radiopurity. Alloyed Cu?Cr layered samples are shown to exhibit significantly increased hardness compared to EF copper, for example showing a 50% increase in exhibited hardness using less than 1% Cr by weight, with limited negative impact to the material?s radiopurity.
10.1016-j.nima.2025.170970	-1		Direct Dark Matter detection and studies on the nature of neutrinos demand detector systems with extremely low background levels, including from radioactivity. Additive-free, electroformed copper, in addition to a set of advantages, exhibits exceptional radiopurity, making it the material of choice for mechanical and structural components for rare-event searches experiments. To satisfy the increasing demand for materials with superior mechanical strength, the development of copper-chromium alloys is pursued. Early investigations explored the synthesis of these alloys by electrodeposition and thermal processing. A materials-design approach is proposed to optimize the fabrication and thermal processing stages of manufacturing. It is assisted by materials modeling tools based on the thermodynamic and kinetic properties of alloy compositions, which enables faster development of novel materials by predicting properties and materials performance. This approach is demonstrated by comparing simulations with previously reported experimental investigations and proposing improved thermal processing.
10.1016-j.nimb.2004.03.079	-1		An open-air furnace has been designed to study in real time the high-temperature surface transformation of materials by Rutherford backscattering spectrometry (RBS) in external beam mode. A device previously designed for the observation of the high-temperature oxidation of galena has been re-designed in order to analyse massive samples and to reach a temperature range up to 700 degreesC and a better temperature regulation (+/-2 degreesC). Experiments are carried out to measure, by RBS using a 3 MeV He-4(2+) external micro-beam, the dynamic growth of oxide layers in air on the surface of copper-tin alloys heated at temperatures varying from 250 to 650 degreesC. The results obtained demonstrate the usefulness of this approach: actually one single measurement series permits to obtain at the same time the composition of oxide layers built on the metal and their growth kinetic laws. In the particular study of bronzes, the growth kinetics obtained by this method show the large influence of tin concentration on the oxidation mechanism. These results are verified by measurements on samples oxidised in an independent closed furnace. The results show also the occurrence of different oxidation mechanisms as a function of temperature. A diffusion mechanism governs the oxidation kinetics only at some temperatures.
10.1016-j.nimb.2014.06.033	-1		Cu-Ti alloys were irradiated with 5.4 MeV Al ions, 7.3 MeV Fe ions, 10 MeV I ions, and 16 MeV Au ions at room temperature and the Vickers microhardness was measured. The hardness once increases by the irradiation with a low fluence, and then it remains almost constant even with increasing the ion fluence. The change in hardness was well correlated with the density of energy deposited through the elastic collisions and not the electronic excitation. The observation of atom probe tomography (APT) did not show any Ti clusters in the irradiated specimens. This result suggests that not Ti clusters but lattic defects (interstitial atoms, vacancies and/or their aggregates) contributed to the increase in hardness of Cu-Ti alloys.
10.1016-j.nimb.2015.01.003	-1		A series of 60 keV He+ implantations was conducted on Cu/W(Re, 5.9 at%) multilayered structures with ion doses from 5 x 10(19) to 5 x 10(21) m(2) under different temperature. Three distinct, temperature-dependent He release mechanisms were found by subsequent X-ray diffraction (XRD) and scanning electron microscope (SEM) investigations. Firstly, with implantation at 300 K (about T/T-m (cu) = 0.22), a certain degree of blistering was observed with a critical dose higher than 5 x 10(21) m(-2). But, at higher temperature irradiation (about T/T-m (cu) = 0.35), samples implanted were characterized by extensive blisters at the dose of 2 x 10(21) m(-2). Finally, at 673 K (about T/T-m(Cu) = 0.5), the specimen flaked and a rough, porous surface formed when the dose was higher than 1 x 10(21) m(-2). The mechanisms involved have been analyzed based on the detailed characterization studies.
10.1016-j.nimb.2016.10.021	-1		A theoretical study is conducted to evaluate the nucleation free energy of copper-vacancy clusters in Fe as a function of the numbers of copper atoms and of vacancies in a cluster. Using this free energy value, cluster nucleation processes during irradiation are investigated. The results clearly show that there are two different types of cluster nucleation paths on the free energy surface; one is the formation of empty voids by jumping over the ridge of the free energy surface, and the other corresponds to a path for the formation of copper clusters by going around the ridge. The dependence of easy nucleation paths on the damage rate is discussed.
10.1016-j.nimb.2024.165506	-1		Cu-1.2 at% Fe samples were irradiated with 1.5 MeV electrons at 333 K and 448 K. Effects of the irradiation were observed as an increase in electrical conductivity and magnetization. In contrast, the Vickers hardness was little changed by the irradiation. The experimental results were explained as due to small Fe-rich clusters produced through radiation-enhanced diffusion. The present study shows that electron irradiation provides a fine control of the magnetic and electric properties of the Cu-Fe alloy.
10.1016-j.nme.2016.07.004	-1		At the D.V. Efremov Scientific Research Institute of Electrophysical Apparatus (SRIEA), elements of the ITER first wall (beryllium tiles and heat removal CuCrZr-bronze) are currently joined by fast brazing (heating with a rate of 150 K/min) using the method of passing a current through brazed samples. For this purpose, rapidly quenched brazing filler metal STEMET 1101 is used. The thermal cycle of brazing consists of a fast heating of the assembly to a temperature of 700-720 degrees C and a subsequent cooling (rate of 60 K/min). However at these temperatures, processes resulting to a loss of the tensile and shear strength of CuCrZr can occur. Therefore, reducing the brazing temperature is a very important task. Optimization of the composition of the Cu-Ni-Sn-P system filler metals and comparative tests of filler metals of various compositions have been carried out in this paper to reduce the brazing temperature of beryllium with CuCrZr. Alloys of the following compositions Cu-6.4Ni-9.2Sn-6.3P (STEMET 1105) and Cu-9.1Ni-3.65n-8.OP (STEMET 1101) were made in the form of rapidly quenched ribbons with a thickness of 50 mu m and a width of 50 mm. They were used to perform furnace brazing by Joule heating (with a rate of 15 K/min) of beryllium with CuCrZr (Be/CuCrZr) at temperatures of 650, 700 and 750 degrees C for 15 min. Metallographic investigations of the zone of brazing and mechanical shear tests of joints before and after the heat treatment at 350 degrees C for 30 h have been conducted. It was found that the joints of Be/CuCrZr brazed at 650 degrees C using STEMET 1105 (tau(s) = 230 MPa) and at 750 degrees C using STEMET 1101 (tau(s) = 260 MPa) had the best shear strength properties. However, there is a significant decrease of the microhardness of CuCrZr from 1570 to 1140 MPa at 750 degrees C, which indicates a significant loss of its strength . The results obtained suggest that the brazing of beryllium with CuCrZr using STEMET 1105 at 650-700 degrees C will not adversely affect the CuCrZr. (C) 2016 The Authors. Published by Elsevier Ltd.
10.1016-j.nme.2018.02.004	-1		Cu-Cr-Zr bronze is used as a heat sink for enhanced heat flux first wall components and structural material for blanket module connectors of ITER. The solution annealing at 980 degrees C for 0.5 h, water quench and ageing at 475 degrees C for 3 h is specified as a reference heat treatment for ITER. The proper heat treatment is provided the better performance taking into account for various structural elements operating under different conditions. However, the actual manufacturing cycle might be different from the recommended one. As the result, heat treatment effects on the properties of Cu-Cr-Zr bronze might be different from that one specified in the ITER documentation. Thus, the effect of various types of heat treatment (in particular the parameters of aging) on the Cu-Cr-Zr alloy's properties is a very important. This paper deals with the investigation of heat treatment effects during aging at a temperature range of 350-750 degrees C and aging time from 5 to 180 min on the structure and physical-mechanical properties of Cu-Cr-Zr bronze.
10.1016-j.nme.2018.05.019	-1		Advanced oxide dispersion strengthened copper alloys are promising structural materials for application in divertor system of future fusion reactors due to high irradiation resistance, high thermal conductivity, and good mechanical properties. In this study, a new ODS copper including 0.42wt%Y2O3 nanosized oxide particles was developed successfully by mechanical alloying method using addition of 1 wt% Stearic acid in Ar atmosphere. Mechanical alloying resulted in decrease of crystallite size to 28 nm in concurrent with increment of dislocation density and hardness to the saturated level of 1.7 x 10(15)m(-2) and 226HV(0.1) after 48 h milling, respectively. Consolidated ODS copper by SPS and then hot roll-annealing at 900 degrees C/60 min showed an average grain size of 1.1 mu m with a near random texture. Furthermore, TEM observations demonstrated fine semicoherent Y2O3 oxide particles distributed with a misfit parameter (delta) of 0.17 in copper matrix with an average size of 10.8 nm and interparticle spacing of 152 nm. Finally, tensile test evaluation determined comparable mechanical properties of the annealed ODS copper (Cu-0.42wt%Y2O3) with Glidcop-Al25 including a yield strength of 272 MPa and total elongation of 12%, by two mechanisms of grain boundary strengthening and oxide particle strengthening.
10.1016-j.nme.2018.06.024	-1		Yttria (Y2O3) dispersed copper alloys were fabricated by an in-situ process combining Mechanical Alloying (MA) and Hot Isostatic Pressing (HIP). In this process, CuO powder was added into Cu(Y) alloy powders halfway during mechanical alloying (MA). To investigate the effects of Y + CuO amount on the MA process and HIP process respectively, four kinds of samples (Cu-0/1/3/5wt%Y2O3) were studied in this research . For powders after MA, it was confirmed by an X-ray diffraction system (XRD) that more Y + CuO addition can refine the grain size. By calculating the lattice parameters from the XRD data, and analyzing the thermal dynamics data that were obtained from the TG-DTA tests, it can be concluded that the Cu, Y were alloyed successfully at first, and then after the CuO addition, reaction between Cu(Y) and CuO occurred, extracting part of Y solute from the Cu (Y) solution. Consequently, the alloying and grain refinement effect together enhance the microhardness of the powders. After consolidation by HIP, the formation of Y2O3 particles were confirmed by XRD. The relative density and the Vickers hardness of the HIP samples increased with the increasing Y2O3 amounts, whereas the electrical conductivity showed an opposite change tendency.
10.1016-j.nme.2020.100773	-1		Dispersion-strengthened (DS) copper alloys with Y2O3 particles are known as high strength and high thermal conductivity materials having potential for heat sink materials of fusion devices. In the previous study on mechanical alloying (MA) and hot isostatic pressing (HIP) processing of DS-Cu alloys, the MA powders showed various morphology and size distribution which influenced the properties of the MA-HIP samples. In this study, the MA alloyed powders with 3 wt% Y2O3 particles were classified by their size and characterized. The particles ranged from fine particles of under 46 mu m to coarse particles of 212 mu m over, and a wide particle size distribution was confirmed. The peeled Cu-O fragments from coarser MA powders are the main source of finer grain with 46 mu m. The finer grains had oxide-like behavior as microstructural and mechanical properties. On the other hand, the coarser powder having over 212 mu m had metal-like behavior as microstructural and mechanical properties. We thought that the classification of the MA powder before HIP process was one of the suitable process to optimize the microstructure and several properties of ODS-Cu alloy.
10.1016-j.nme.2021.100903	-1		Oxide dispersion strengthened (ODS) Cu alloys are expected to have high strength and superior irradiation resistance that are necessary characteristics for the divertor components of fusion reactors. The present study investigated the irradiation hardening after a self-ion irradiation experiment that was carried out at 100 degrees C with 5.1 MeV Cu2+ ions up to three displacements per atom in ODS-Cu and compared it to that of non-ODS Cu materials such as mechanically alloyed (MAed) Cu and single crystal (SC) Cu. Nanoindentation hardness tests and micro-pillar compression tests on 1 mu m cubic pillars were carried out to evaluate the mechanical strength before and after the ion-irradiation. Both MAed-Cu and ODS-Cu showed good resistance against irradiation hardening, while SC-Cu showed a larger increase in the nanoindentation hardness and in the micro-pillar compression yield stress. Relationships between the nanoindentation hardness, Vickers hardness and micropillar yield stress were discussed considering the effects of both specimen/indentation size and irradiation hardening.
10.1016-j.nme.2021.101075	-1		Dispersion strengthened copper alloys have been produced following an innovative powder metallurgy route. Copper and yttrium acetate powders have been mechanically alloyed and posteriorly thermal treated at 923 K for 3 h and 15 h under a hydrogen atmosphere in order to transform the yttrium acetate into Y2O3. Subsequently, the powders were consolidated by hot isostatic pressing. It has been concluded that the duration of the thermal treatment of the powder is a determining factor in the degree of densification of the alloy. The study of the microstructure by Scanning Electron Microscopy and Electron Backscatter Diffraction has revealed the presence of micrometer and submicrometer grains and nanometric Y-O enriched Cu particles embedded in the copper matrix, the mean grain size being smaller for the sample produced from the powder thermal treated for 15 h . Transmission Electron Microscopy investigations concluded that the nanoparticles exhibit a spherical shape with a size up to 25 nm and correspond to monoclinic Y2O3. Annealing twins have been also observed, especially in the material produced from thermal treated powder for longer. The mechanical properties have been inferred from Vickers microhardness measurements and compression tests. Below 473 K the yield strengths of the produced materials are greater than that of pure copper and above 473 K are close to them. From the study of the thermal properties of the densest material it has been found that its thermal conductivity remains nearly constant in the temperature range 300-773 K, and its value is around 85% the thermal conductivity of CuCrZr, the reference material for ITER.
10.1016-j.nme.2022.101123	-1		To evaluate the microstructure and hardness stability at high temperatures, Cu-Al2O3 produced via internal oxidation method was subjected to annealing at 200, 300, 400, 500, 600, 700, 800, 900 and 1000 ?degrees C for 1 h . Pure copper (T2) and CuCrZr are selected for comparison. Then the grain size, particle characteristics and softening temperatures are characterized systematically. Finally, grain growth kinetics and strengthening mechanism were clarified by quantitative calculation. The results indicate that Cu-Al2O3 has the most stable grain size. After annealing at 1000 ?degrees C, the average grain size of T2, CuCrZr and Cu-Al2O3 increases from 16 to 185 mu m, 5.63 to 83.13 mu m and 0.18 to 0.31 mu m, respectively. The second phase is Cr-rich particle in CuCrZr and Al2O3 in CuAl2O3. The former particle suffers partial dissolution and rapid Ostwald ripening while the latter one present stable feature during high-temperature annealing, which leads to the softening temperatures of 200-300 ?degrees C, 500-600 ?degrees C and 900-1000 ?degrees C for T2, CuCrZr and Cu-Al2O3, respectively. Besides, although the calculated activation energy of grain growth in CuCrZr and Cu-Al2O3 are 137 and 37.5 kJ.mol(-1), respectively, stable Al2O3 and the greater difference of elastic modulus between Al2O3 and Cu matrix inhibit the grain growth in Cu-Al2O3. Moreover, for the CuCrZr and Cu-Al2O3 annealed at 800 and 1000 ?degrees C, the main strengthening contribution is from grain boundary. The stable nanometer grains induced by Al2O3 particles are chiefly responsible for the higher softening temperature of Cu-Al2O3 than that of CuCrZr.
10.1016-j.nme.2022.101144	7	irradiation; shear; grain; ta; deformation; size; radiation; voids; nanocrystalline; simulations; similar; void; temperature; irradiated; boundaries	The sink strengths of precipitate/matrix interfaces in Cu alloys, were investigated by performing in-situ observation of electron irradiation in high-voltage electron microscopy (HVEM). Fine black spot defects, which seemed to be dislocation loops were observed at irradiation temperature ranging between RT and 373 K in Cu-Cr-Zr, Cu-Cr and GlidCop Al-60 alloys with low number density. In Cu-Cr, loops formed on a part of precipitates interfaces. Hence, a part of precipitate/matrix interfaces is a sink with interstitial bias. Whereas, most of the interfaces are neutral sinks for point defects. In the case of Cu-Cr-Zr and GlidCop Al-60, black spots formed around dislocation, which were induced during two-step heat treatment. The results showed that the precipitate/ matrix interface of Cr-rich precipitates in Cu alloys serve as a strong sink for point defects.
10.1016-j.nme.2022.101159	2	corrosion; surface; film; electrochemical; films; spectroscopy; layer; current; solution; potential; resistance; composition; x-ray; ions; showed	Precipitation-hardened Cu-Cr-Zr alloy is proposed as a heat sink material for various components of the ITER (blanket first wall, divertor, electrical straps and others) owing to its high strength, high conductivity and superior resistance against neutron irradiation. ODS-Cu (Oxide Dispersion Strengthened Copper) is also selected as a candidate material. Corrosion properties of alumina-dispersed copper alloys (GlidCop (R) CuAl15, CuAl25), aevaluated by electrochemical methods in 0.1 M and 0.01 M sodium sulfate (Na2SO4) solutions. In open circuit potential (OCP) measurement in 0.1 M Na2SO4 solution, the potential of all alloys decreased immediately after immersion and then gradually decreased. CuAl15 showed good corrosion resistance in the OCP measurement with little potential drop. In the polarization curve measurements, a difference was observed for each material in the cathode region. The corrosion current densities tended to be higher for CuAl25 and Cu-Cr-Zr, and the corrosion potential was also low in both solutions. In these alloys, the surface observation after the polarization curve measurements showed variations in the thickness of the Cu2O passivation film, and there were large areas where the film was thought to be thin. In Cu-Cr-Zr, coarse columnar Cr precipitates and segregation of Zr at the precipitate/matrix interface are thought to deteriorate corrosion resistance. In the case of CuAl25, it is suggested that dissolution of the passivation film is enhanced due to large volume fraction of alumina particles.
10.1016-j.nme.2022.101187	-1		Cu5Cr35Fe35V20-X-5, with X = Ti, Ta or W, alloys were produced by arc melting to assess their feasibility to be used as structural materials and as interlayer in cooling systems. The microstructure and mechanical properties of the materials were analyzed in as-cast and aged states. In the as-cast state the structure of the three alloys is BCC, but formation of the intermetallic Fe7Ta3 is observed in Cu5Cr35Fe35V20Ta5. Thermal aging treatment at 700 degrees C caused significant changes in the microstructure of Cu5Cr35Fe35V20W5 and the formation of the sigma phase. Thermal treated Cu5Cr35Fe35V20Ta5 and Cu5Cr35Fe35V20Ta5 exhibit high mechanical strength and excellent compressive ductility but show work softening due to the appearance of dynamic recovery mechanisms. Type-A serration behavior is observed for Cu5Cr35Fe35V20Ta5. Both, the complexity of their microstructures and their differences are responsible for the different mechanical behavior of the three alloys.
10.1016-j.nme.2023.101480	-1		This study presents a comparative analysis of the microstructure and performance stability of Cu-Al2O3 and Cu-Y2O3 alloy after annealing at temperatures ranging from 600 degrees C to 1000 degrees C. The evolution of grain size, nano-particle size, and mechanical properties was investigated using transmission electron microscopy (TEM), scanning electron microscope (SEM), electron backscattered diffraction (EBSD), X-ray diffraction (XRD) and mechanical tests. The results indicate a more rapid degradation of yield strength and ultimate tensile strength in Cu-Y2O3 alloy after annealing at a temperature of >= 800 degrees C, while the mechanical properties of Cu-Al2O3 are relatively stable. The main cause of the decrease in mechanical properties is attributed to the rapid grain growth observed under annealing temperatures of >= 800 degrees C. Cu-Y2O3 alloy exhibited lower grain size stability, and the activation energy of grain growth was estimated to be 115 kJ/mol, which is lower than that of Cu-Al2O3 but comparable to the value reported in the literature for CuCrZr alloy. In contrast, the activation energies for coarsening of Y2O3 and Al2O3 nanoparticles were determined to be 58.9 kJ/mol and 44.1 kJ/mol, respectively. These results indicate that Y2O3 nanoparticles were found to be more stable than Al2O3 nanoparticles.
10.1016-j.nme.2024.101580	-1		Precipitation-hardened Cu-Cr-Zr alloy is proposed as a heat sink material for various components of the ITER owing to its high strength, high conductivity, and superior resistance against neutron irradiation. Oxidedispersion-strengthened copper (ODS-Cu) was selected as the candidate material. Hydrogen embrittlement of Cu-Cr-Zr, Cu-Cr, and ODS-Cu (GlidCop (R) CuAl60) alloys was evaluated using the slow strain rate technique (SSRT) in 0.1 M sodium sulfate (Na2SO4) solutions under cathodic hydrogen charging or after D2 gas exposure. Thermal desorption spectroscopy (TDS) measurements were performed to estimate the differences in the hydrogen-trapping sites using hydrogen charging methods. According to the TDS results, the quantity of hydrogen retained in ODS-Cu exceeded that in the other alloys by an order of magnitude because of hydrogen trapping at the grain boundaries and the particle/matrix interface. Cu-Cr-Zr alloys tend to trap more hydrogen than Cu-Cr alloys because of the addition of Zr. As a result of the SSRT, no hydrogen embrittlement was observed in any alloy, regardless of the hydrogen charging method. All alloys exhibited excellent hydrogen embrittlement resistance under the conditions adopted in this study.
10.1016-j.nme.2024.101599	-1		Two types of Cu composites containing 3 wt% Y2O3, with and without a process control agent (PCA), were fabricated using mechanical alloying (MA) and hot isostatic pressing (HIP). The results showed that the addition of PCA effectively inhibited the growth of MA powders. This was attributed to the PCA forming a lubricating film on the MA powders, preventing adhesion between the powders. However, residual PCA after heat treatments contained C impurities, which had a significant impact on thermal conductivity. The lubricating film weakened the binding force between MA powders during sintering, resulting in poor mechanical performance. Additionally, the lubricating film slowed down the MA process by eliminating the frictional stress caused by oblique collision. Frictional stress plays a crucial role in the dissolution of Y into the Cu matrix due to the tearing of Y-rich particles and the fracture of MA powders. Therefore, it is necessary to explore an optimum PCA that can be easily removed before sintering, slow down the growth of MA powders, and avoid reducing the efficiency of the MA process during the synthesis of Cu-Y2O3 composites by mechanical alloying.
10.1016-j.nme.2024.101644	-1		To prepare high-performance copper -based composites, Y 2 O 3 /W multiphase reinforced copper -based composites were synthesized through mechanical alloying and spark plasma sintering, and the mole ratio of W and Y 2 O 3 was explored. It is found that the incorporation of W inhibited the growth of copper particle during ball milling, and facilitated the refinement of Y 2 O 3 . Compared to conditions without W addition, the Y 2 O 3 particle diameter reduced from 97.96 nm to 33.4 nm when same mole W was added. Furthermore, copper grains were refined, resulting in a higher tensile strength of 305 MPa and elongation of 15.6 %. At 400 degrees C, the 5:5 sample exhibited a higher thermal conductivity of 299 W/(m & sdot; K). Nano -scale particles were uniformly distributed within the copper matrix, and the interaction between W and Y 2 O 3 inhibited nanoparticle coarsening, leading to the formation of a more stable Y 2 WO 6 phase during sintering, which is also better for the purification of the copper matrix.
10.1016-j.nme.2024.101720	-1		Compared to CuCrZr, oxide dispersion strengthened copper alloy (ODS-Cu) exhibits higher stability of properties under irradiation and exposure to elevated temperatures, demonstrating broad application prospects in divertor components. Oxygen-free high thermal conductivity copper (Cu-OFHC) has been frequently employed as an interlayer between Wand Cu-based alloy in the fabrication of W/Cu divertor components. This study investigates the effect of joining temperature together with the addition of a Ni interlayer on the interface microstructure and mechanical properties of the Cu-OFHC/ODS-Cu joints. As the joining temperature increased from 680 degrees C to 900 degrees C, the interface bonding ratio of the Cu-OFHC/ODS-Cu joints improved from 40.4% to 95.8%, and the impact toughness increased from 23.4 J/cm2 to 133.1 J/cm2. With the addition of a Ni interlayer, the interface bonding ratio increased from 40.4% to 90.3%, and the impact toughness improved from 23.4 J/cm2 to 122.5 J/cm2. Increasing the joining temperature or adding a Ni interlayer effectively reduced interfacial voids, enhanced the interface bonding ratio, and consequently improved the impact toughness of Cu-OFHC/ODS-Cu joints. Then, the W/Cu/ODS-Cu monoblock mock-ups with good interfacial bonding were successfully fabricated under two conditions: at a joining temperature of 900 degrees C without an interlayer and at 680 degrees C with a Ni interlayer. These results provide a fundamental understanding for achieving high-quality Cu-OFHC/ODS-Cu joints and offer technical support for the engineering preparation of W/Cu/ODS-Cu components in future fusion devices.
10.1016-j.oceaneng.2025.122129	-1		In this work, a first ever application of Polymer Derived Ceramics coatings based on SiOC glasses, on Cu-based alloys (pure Cu and CuNi10Fe1.6Mn cupronickel) for marine applications was reported. Sol-gel method and dip-coating technique with further thermal treatment at 800 degrees C in Ar atmosphere were used to produce the coatings that were subjected to the corrosion resistance studies with salt spray testing in 3.2 % NaCl environment at 35 degrees C. Advanced characterization of microstructure (Optical and SEM microscopy) with elemental composition (EDS) as well as structure (X-Ray Diffraction, FTIR and Raman spectroscopy) of as-coated and corroded (bare and coated) specimens was performed. Conducted studies revealed the issue of cracks formation during pyrolysis step, as well as no improvement in pure Cu corrosion resistance by means of SiOC coating. However, despite cracks, a considerable enhancement of CuNi10Fe1.6Mn alloy corrosion resistance was observed due to the high chemical compatibility of SiOC coating and used cupronickel. It was possible to illustrate a phase distribution in crosssectional analysis using the Raman confocal imaging, which revealed mostly Cu2O mixed with spinel-type (Cu,Fe,Mn,Ni)3O4 oxide and Mn oxides in corrosion products, as well as Mn oxides and NiO within the inter-diffusion layer that chemically bonded ceramic coating enriched in strong, resistant Si-C bonds and free carbon phase, to the metallic substrate providing an effective barrier against aggressive Cl environment.
10.1016-j.optlaseng.2010.02.009	-1		Ni-Co duplex coating has been successfully cladded on copper substrate by continuous wave CO2 laser. The average microhardness of cladded coating was 635 HV0.05, which was about 7 times of Cu substrate (92 HV0.05). During sliding wear tests, the volume loss of copper substrate was about 7 times of Ni-Co duplex coating at 60 min. The high microhardness and crack free advantages of Ni-Co duplex coating, were favorable to reduce the plastic deformation and adhesive wear of copper substrate, resulting in the improvement of wear properties.
10.1016-j.optlaseng.2017.06.028	5	materials; thermal; heat; properties; material; welding; sintering; fusion; strength; laser; heat sink; thermal conductivity; mechanical; sink; manufacturing	Laser-based layer manufacturing of metals, also known as additive manufacturing, is a growing research field of academic and industrial interest. However, in the associated laser-driven processes (i.e. selective laser sintering (SLS) or melting (SLM)), optimization of some parameters has not been fully explored. This research aims at determining how the angle of laser scanning pattern (i.e. build orientation) in SLS affects the mechanical properties and structure of an individual Cu-Sn-Ni alloy metallic layer sintered in the process. Experiments consist in varying the angle of the scanning pattern (0 degrees, 30 degrees, 45 degrees 60 degrees and 90 degrees relative to the transverse dimension of the piece), at constant scanning speed and laser beam power, producing specimens of different thicknesses. A noticeable effect of the scan angle on the mechanical strength and degree of densification of the sintered specimens is found. Thickness of the resulting monolayer correlates negatively with increasing scan angle, whereas relative density correlates positively. A minimum porosity and maximum UTS are found at the angle of 60 degrees. It is concluded that angle of the scanning pattern angle plays a significant role in SLS of metallic monolayers.
10.1016-j.optlastec.2019.105577	-1		Grain refinement and homogenization of Cr phase were achieved by laser surface melting (LSM) method, and the properties of Cu-Cr alloy were significantly improved. In this study, LSM of Cu-50Cr alloy (wt%) was conducted with a high power density (10(6) -10(7) W/cm(2)) laser beam, the microstructure and the properties of melt layer were investigated. The size of Cr phase was effectively refined from hundreds of micron scale to several micron scale, and the average size of Cr particles decreased to a few hundred nanometers. High cooling rate effectively inhibited coarsening effect on the Cr particles during liquid phase separation. Spherical Cr particles were dispersed in the melt layer with a thickness of 165 +/- 20 mu m. Microhardness was obviously enhanced and the maximum hardness was 232HV, which was 2.8 times that of the substrate. Arc duration of the LSM treated contacts increased up to 18%. The withstanding voltage of the fixed and the moving contact increased to 28.7% and 35.4%, respectively. The results show that LSM is an effective method to refine the microstructure of Cu-Cr alloy, and it is a promising modification method for electrical Cu-Cr vacuum contacts.
10.1016-j.optlastec.2019.105879	17	wear; composites; coating; friction; composite; coatings; surface; tribological; properties; wear resistance; resistance; powder; sliding; matrix; wear rate	To improve the wear resistance of gray cast iron and the quality of the laser cladding coating, a composite coating was designed and produced using Cu-Ti-Ni blending powder on the surface of gray cast iron by fiber laser cladding system. The phase constituents and microstructure of the composite coating were investigated using X-ray diffraction (XRD) and scanning electron micrograph (SEM). Microhardness and wear resistance of the coatings were evaluated. The experimental results indicated that TiC reinforced composite coating was produced and the matrix of the laser cladding zone composed of alloy gamma-Fe, acicular martensite, and alpha-Cu. Microscale TiC particles were synthesized in the laser melted pool using the graphite phase of the substrate and the titanium atom of the blending powder. The surface properties of gray cast iron was improved by TiC reinforced composite coating. The microhardness of the laser cladding zone was approximately 2 to 3 times that of the substrate and the wear resistance of the coating was significantly improved. The wear mechanism of the coating was adhesive wear and abrasive wear because the matrix was soft alloy gamma-Fe and alpha-Cu. The coating could significantly improve the performance of grey cast iron under severe service conditions.
10.1016-j.optlastec.2021.107418	2	corrosion; surface; film; electrochemical; films; spectroscopy; layer; current; solution; potential; resistance; composition; x-ray; ions; showed	This paper presents the direct writing of thermoelectric couples composed of Cu-Ni alloy in ambient atmosphere. Patterns of Cu, Ni, and Cu-Ni alloys were directly written by the rapid heating and reduction of glyoxylic acid metal (Cu, Ni, and Cu/Ni mixed) complexes on glass substrates using femtosecond laser pulses without significant oxidation. The Seebeck coefficient of the patterns depended on the concentration ratio of Cu to Ni in the alloy, which could be controlled by the concentrations of the glyoxylic acid Cu/Ni mixed complex. A thermoelectric couple composed of p-type Cu and n-type Cu-Ni alloy generated an open-circuit voltage depending on the temperature gradient. This direct writing technique of pure metal and alloy allows various sensors to be printed in air.
10.1016-j.optlastec.2022.108210	3	sma; shape; shape memory; memory; smas; superelastic; bars; damping; cu-al-mn; mechanical; bending; applications; numerical; sma bars; material	The term 'shape memory alloys' (SMAs) refer to a group of metallic materials that have the ability to return to a previously defined shape when subjected to the appropriate thermal or loading cycles. They are now being employed in different real-life applications. Cu-Al-Fe is a High Temperature Shape Memory Alloy (HTSMA) and could replace Ni-Ti SMAs. Conventional machining technologies are not efficient enough in machining SMAs, and thus the properties of the SMAs are affected. One of the most successful technologies for processing these alloys is Laser Beam Machining (LBM). This work shows an investigation of the effect of process variables in laser machining on SMA. Differential scanning calorimetry, X-Ray Diffraction, Optical Microscopy, Scanning Electron Microscopy, and Hardness tests were used to analyze the laser-machined material. It has been found that power was the highest influencing variable which affects Material Removal Rate (MRR) and Surface Roughness (Ra), and the second most influencing parameter was cutting speed. DSC thermograms confirm that the Shape Memory Effect (SME) and the transition temperatures of the SMA have not been much affected after machining. The hardness of the machined surface slightly increased after machining, owing to the formation of a re-solidified layer.
10.1016-j.optlastec.2022.108878	-1		Reducing the damage caused by friction and wear to components such as Al alloy parts could extend the service lives of parts in automobile and other industrial fields. An effective approach to this is improving the anti-friction properties of key surfaces. In this study, an annular laser cladding (ALC) method was designed, an energy ab-sorption model of the ALC process was established, and the cladding of a CuPb10Sn10 copper alloy coating on a 42CrMo steel surface was studied experimentally. The effects of the ALC process parameters on the laser ab-sorptivity, porosity, and microstructure of the ALC sample were analyzed, and the coating properties (e.g., microhardness and anti-friction properties) were evaluated. The results showed that laser cladding of a CuPb10Sn10 copper alloy coating or other coating materials with low absorptivity could be realized on the surface of 42CrMo steel using the ALC process. The ALC process increased the laser absorptivity to 58 %, and the porosity of the ALC sample was reduced to 0.39 %. The coating microstructure was divided into three layers, in which the top layer of the Cu-rich phase had a uniform structure and no macroscopic crack defects. The main anti-friction component Pb phase and other Cu, Pb, and Sn elements were uniformly distributed. The micro -hardness of the coating fluctuated, and the value of the top-layer Cu-rich phase was approximately 120 HV0.3. The shear strength of the coating was 194 MPa, and the friction coefficient of the coating decreased by approximately 50 % to 0.19. The ALC method effectively improved the laser absorptivity during the laser cladding of copper alloys on iron substrates, providing theoretical guidance for designing and manufacturing anti-friction functional components in the automotive industry and other fields.
10.1016-j.partic.2016.12.006	-1		Cu-Ni bimetallic nanoparticles surface-capped with dodecanethiol were prepared via the controlled reduction of nickel nitrate and copper nitrate in the presence of dodecanethiol as ligand and hydrazine hydrate as reductant. The morphology and structure of the Cu-Ni nanoparticles were analyzed by transmission electron microscopy, X-ray diffraction, X-ray photoelectron spectroscopy, Fourier transform infrared spectrometry, and thermal gravimetric analysis. Furthermore, the tribological properties of the Cu-Ni nanoparticles as a lubricant additive in liquid paraffin were evaluated with a four-ball machine, and the morphology and elemental composition of the worn surfaces were analyzed by three-dimensional non-contact surface profilometry and X-ray photoelectron spectroscopy, respectively. The results indicated that Cu-Ni nanoparticles prepared at a sufficient dodecanethiol concentration showed almost no signs of aggregation, and exhibited good dispersibility in various apolar solvents. The addition of the Cu-Ni nanoparticles improved the load-carrying capacity as well as friction-reducing and anti-wear abilities of liquid paraffin, attributed to the rolling effect of agglomerated Cu-Ni nanocores released by the Cu-Ni nanoparticles during sliding, and the formation of a boundary lubricating film containing tribochemical reaction products such as iron oxides and iron sulfate.
10.1016-j.physa.2019.02.041	-1		In the present paper the sedimentation process in Cu-Sn alloy is discussed in two ways: by experimental and numerical approach . The sedimentation process was executed at the following conditions-the rotation speed 35,000 RPM, the radii was between 88 and 93 mm, temperature 180 degrees C and time 2 h . During the experiment the separation of the Cu-3 Sn and Cu6Sn5 phase was observed. The sedimentation process clearly influenced the morphology of the alloy. Moreover, the model based on the bi-velocity method is presented. The model allow for determination of the phase fraction when centrifugal force acting on the sample.
10.1016-j.physb.2003.10.028	6	grain; deformation; strain; strength; dislocation; cu-; tensile; size; ecap; grain size; sfe; ductility; hardening; high; stress	Bronzes exhibit a combination of high heat conductivity and excellent mechanical strength . They have many important commercial industrial applications. Isothermal tensile creep curves of Cu-2 wt% Sn were obtained in the solid solution region at temperatures 573, 623, 673 and 723 K under constant stresses ranging from 64 to 111 MPa. The values of the transient creep parameters beta and n showed dependence on the deformation temperatures, T, and the applied stress, sigma. beta increased with both T and sigma while n decreased. n is expected to be independent on the temperature at a stress of 208.3 MPa. The dependence of the steady-state creep rate, epsilon, on the grain diameter, d, satisfies a petch type equation epsilon = epsilon(o) + bd.epsilon increases with both a and T for any grain diameter. The stress exponent, m, is independent on d but relates to the deformation temperature, T, by the empirical formula m = 0.655 + 45 x 10(-4) T. the activation energy of the steady-state creep, Q, decreases with increasing the grain diameter. For any grain diameter, Q is slightly affected by the applied stress. The straight line obtained by the best fitting for the relation between Q and 1/d, has an intercept of 64.9 kJ/mol. This value may correspond to the activation energy of the dislocation climb mechanism in a single crystal of Cu-2 wt% Sn alloy.
10.1016-j.physb.2005.03.009	4	transformation; martensite; martensitic; phase; shape; beta; memory; shape memory; temperature; temperatures; martensitic transformation; gamma; transformation temperatures; effect; thermal	The reverse and forward transformation temperatures, oxidation behaviour and microstructure of a neutron irradiated Cu-13.5 wt% Al-4 wt% Ni shape memory alloy have been investigated. The alloy was irradiated for 3.6 and 7.2 ks with thermal neutron flux. Neutron flux is 8 X 10(12) n cm(-2) s(-1), E > 1 McV. It was seen from differential scanning calorimetry (DSC) that transformation temperatures of the martensite double left right arrow austenite decreased and transformation enthalpies increased after neutron irradiation. The oxidation behaviour was also determined using thermogravimetric analysis (TGA). Neutron irradiation increased the mass gain rates of the alloy. The martensite morphology disappeared after neutron irradiation. As a result, irradiation leads to observable changes in the structure of the alloy.
10.1016-j.physb.2006.03.029	-1		Structural and magneto resistive properties of Fe-Cu-Ni granular thin films exhibiting giant magnetoresistance were investigated. A number of samples were prepared by DC magnetron sputtering at a sputtering pressure of 0.001 mbar of Ar. The compositions of the samples were determined by energy-dispersive X-ray analysis. X-ray diffraction patterns showed only Cu(1 1 1) peaks in all the samples and no Fe or Ni peaks were observed. The behaviour of d(111) of Cu indicates the presence of Ni atoms in the Cu grains. From Vegard's law for bulk Cu-Ni alloy, we have concluded that the value of d(111) of Cu obtained in our samples is a measure of the amount of Ni dissolved in the Cu grains. The electron diffraction patterns obtained on selected samples showed many Cu reflections and they also did not show any reflection from Fe or Ni. Surface morphology of some samples studied by atomic force microscopy showed that the films are smooth and their typical surface roughness is 5 angstrom. Magnetoresistance measurements on the samples upto 20 kOe showed interesting results. The plots of magneto resistance versus concentration showed maxima for certain concentration ranges and these values of maxima were found to be almost unaffected even when a large amount of Ni as high as 30% was present in the Cu grains.
10.1016-j.physb.2007.04.041	9	magnetic; magnetization; magnetoresistance; temperature; superparamagnetic; annealing; gmr; field; magnetic properties; ferromagnetic; granular; samples; magnetic field; melt-spun; particles	Nanostructured magnetic Cu- 10 wt% Co alloys have been processed by ultra rapid solidification, in a twin roller melt spinning device. This solidification method (two wheels) is known to promote a more uniform microstructure as compared with that resulting in single wheel devices. The structural properties of ribbons processed at tangential wheel speeds of 5 and 23 m/s, in the as-cast condition and after a heat treatment of I h at 923 K, are investigated by X-ray diffraction techniques; the magnetic properties are also characterized by M-H loop measurements and the electric resistance measured as a function of the applied magnetic field at 300 K. The M-H loops can be described by the sum of a superparamagnetic like component involving small, interacting clusters of pure Co, and a soft ferromagnetic contribution which is likely to arise in the matrix. The X-ray spectra are consistent with a Cu matrix exhibiting a spinodal like Co concentration profile even in specimens in the as-cast condition. Isothermal annealing above 873 K results in the formation of larger Co clusters, in an improvement of the nominal coercivity and also leads to a higher polarization at a maximum field of 1. 5 T. On the other hand, magneto resistance effects are observed in as-cast samples solidified at 23 m/s but not in the specimen cooled at 5 m/s nor in those heat treated for I It at 923 K.
10.1016-j.physb.2007.04.086	-1		Cu-Hf-Ti ternary metallic alloys were prepared by melt spinning. The thermal stability of the alloys with various Ti contents was studied by differential scanning calorimetry. The evolution of short range order with annealing treatment was also investigated by means of perturbed angular correlation. The results for the initial as-spun alloys indicate that the short range order can be described by a dense packing of atoms. The variation of electric field gradient with alloy composition is comparable to that previously observed in binary and multi-component Zr- and Hf-based amorphous alloys.
10.1016-j.physb.2009.02.014	-1		The size- and shape-dependent formation enthalpy has been studied based on size and shape-dependent cohesive energy, where the shape effect is described by the shape factor. For Cu-Au alloy particles, the formation enthalpy is more negative than that of the bulk alloy. For Cu-Ni alloy particles, the formation enthalpy is negative despite of the positive value of bulk. To study the shape effect on formation enthalpy, the cubic and the spherical nanoparticle are discussed in details. There are eight shape configurations for the initial pure metallic particles and the alloy particles. By calculation of the formation enthalpy of Cu-Au and Cu-Ni alloy nanoparticles, it is found that the most negative formation enthalpy is for cubic+cubic -> spherical case, and the highest energy is for spherical+-spherical -> cubic case. The curve of formation enthalpy may be approximately symmetric if the initial shapes of the two pure metallic particles are the same and asymmetric if the two initial shapes are different. The shape effect on formation enthalpy decreases with increasing the particle size. The present results also suggest that one may prepare some non-spherical alloy particles experimentally in some concentration ranges although the bulk elements are immiscible.
10.1016-j.physb.2009.08.022	4	transformation; martensite; martensitic; phase; shape; beta; memory; shape memory; temperature; temperatures; martensitic transformation; gamma; transformation temperatures; effect; thermal	Changes in 3d states occupancy associated with the inverse martensitic transformation in two samples of Cu-Al-Zn alloys with 2H and 18R martensitic structures were investigated by electron energy loss spectroscopy (EELS). The Cu L-2,L-3 white-lines intensities, which reflect the unoccupied density of states in 3d bands, were measured in situ, during the phase transformation in both the martensite and austenite phases. We find that the white-lines intensity decreases during the inverse transformation, when going from martensite to austenite. Even though the initial 3d occupation numbers in 2H and 18R martensitic structures are different, after the transformation, the 3d occupation numbers in the now austenitic structure have decreased in both samples, indicating that some electrons left Cu 3d bands during phase transformation. Interestingly enough, the occupation numbers in the final phases, which have the same structure, reach the same value, indicating that changes in EELS spectra are a consequence of structural changes.
10.1016-j.physb.2010.09.047	13	clusters; atomic; glass; atoms; composition; dynamics; metallic; icosahedral; glasses; simulations; molecular; cu-zr; molecular dynamics; metallic glasses; structural	Molecular dynamics simulations for the crystal, amorphous and liquid Cu46Zr54 alloy were carried out on a system with up to 2000 particles, using a pairwise potential of the Rosato-Guillope-Legrand type. All simulations were done in the microcanonical ensemble, for a initial density of 5.76 g/cm(3), at different temperatures. A detailed analysis has been made by means of the pair-correlation function, coordination number, angle distribution, diffusion coefficient and vibrational density of states. We compared the main peaks of the amorphous phase with experimental data, obtaining a good agreement. The analysis of coordination number for the amorphous phase shows that the main building block of this phase are distorted icosahedron.
10.1016-j.physb.2011.06.077	0	solidification; phase; magnetic; magnetic field; undercooling; field; liquid; separation; peritectic; immiscible; cu-; dendrite; phase separation; microstructure; primary	Applying the melt-fluxing method, rapid solidifications of undercooled Cu50Co50 immiscible and Cu70Ni30 solid solution alloys were performed to investigate the grain refinement regularity at moderate undercooling. Due to the essential distinction of physical properties between these alloys, grain refinement phenomenon was detected in Cu50Co50 alloy with a tendency of liquid separation, while dendrite structure appears for Cu70Ni30 alloy. The association of microstructure morphology to non-equilibrium solidification process was constructed with the description of recalescence degree as a function of undercooling. Quantitative thermodynamic calculation for the undercooled liquid of the researched systems was carried out to elucidate the influence of liquid separation on the variation of Gibbs free energy for the subsequent rapid solidification, which gives a better understanding of the as-observed experimental results.
10.1016-j.physb.2012.06.024	0	solidification; phase; magnetic; magnetic field; undercooling; field; liquid; separation; peritectic; immiscible; cu-; dendrite; phase separation; microstructure; primary	The resistivity behavior of undercooled liquid Cu-Ni and Cu-Co alloys had been studied in the contactless method, to probe the structure transition in undercooled melts during the cooling process. Over the entire concentration range, linear behavior of resistivity with temperature was obtained in liquid and undercooled liquid Cu-Ni system. It implied that the formation of icosahedral order might not influence the electron scattering in undercooled liquid Cu-Ni alloys. Similar results were obtained in Cu-Co system in the vicinity of liquidus temperature. A turning point was obvious in temperature coefficient of resistivity for undercooled liquid Cu-Co alloys around the bimodal line, which was interpreted to be responsible for metastable liquid-liquid phase separation. During liquid phase separation process, resistivity decreased and the temperature coefficient of resistivity was larger than that of homogeneous melts. In combination with transmission electron microscopy and scanning electron microscope studies on the as-solidified microstructure, this was interpreted as the formation of egg-type structure and concentration change in Cu-rich and Co-rich phases. The mechanism controlling the separation and droplets motion was also discussed in undercooled liquid Cu-Co system. (c) 2012 Published by Elsevier B.V.
10.1016-j.physb.2012.10.015	-1		In this study, local atomic rearrangements of Cu-%26.8Al-%2.5Ni ternary alloys (3 A) are investigated during their crystallization processes from amorphous phase using molecular dynamics (MD) simulations. These simulations are based on the Sutton-Chen type of embedded atom method (SCEAM) that employs many-body interactions. In order to analyse the structural development obtained from MD simulation, the simulation techniques are used as bond order parameter, radial distribution function (RDF). Local atomic bonded pairs and short range order properties in the model alloy have been analysed using the Honeycutt-Andersen (HA) method. The kinetics of the crystallization is described by Johnson, Mehl and Avrami (JMA) model, which has been analysed with MD method by using the crystalline bonded pairs. The simulation results show that the structural variation of local atomic bonded pairs is of great importance to understand the crystallization kinetics from amorphous phase to crystal phase during the crystallization.
10.1016-j.physb.2016.07.010	-1		We present a comprehensive study of electrical and thermal conductivities, specific heat and magnetic susceptibility of rapidly crystallized Cu100-x,Zr-x (x = 20-90) alloys. X-ray diffraction analysis has revealed that all the prepared compositions had strongly textured and distorted crystal structures. Different monoclinic and other non-equilibrium phases were detected in the case of glass-forming samples, whereas the alloys without a tendency to form glassy state show almost equilibrium phase content. Metallic type of electrical conductivity and the Kondo anomaly were observed for all the examined samples. It was found that the electrical resistance data cannot be adequately described within the standard Bloch-Gruneisen theory. We use the Debye characteristic temperature as a linear function to fit the electrical conductivity accurately. The composition dependence of the electron density of states at the Fermi level (DOS) has been extracted from room temperature magnetic susceptibility. We found that the glass-forming alloys are characterized by abnormally large values of DOS, which are comparable to those of glassy analogues. Noticeable anharmonic contribution in total specific heat has been revealed for all the studied compositions. In order to estimate the effect of anharmonicity in the system under consideration, we analyzed composition and temperature dependencies of the studied thermal characteristics related to the Gruneisen coefficient. Basing on the results obtained in this study we propose a phenomenological concept to explain abnormal behavior of physical properties of glass-forming Cu-Zr alloys within the standard solid state theory taking into account anharmonic effects.
10.1016-j.physb.2018.01.032	-1		This work reports the indentation creep behaviors of two Si2Zr3/amorphous Cu-based composite alloys utilizing nanoindentation technique. By analysis with Kelvin model, the retardation spectra of alloys at different positions, detached and attached regions to the intermetallics, were deduced. For the indentation of detached regions to Si2Zr3 intermetallics in both alloys, very similarity in creep displacement can be observed and retardation spectra show a distinct disparity in the second retardation peak. For the indentation of detached regions, the second retardation spectra also display distinct disparity. At both positions, the retardation spectra suggest that Si elements may lead to the relatively dense structure in the amorphous matrix and to form excessive Si2Zr3 intermetallics which may deteriorate the plastic deformation of current Cu-based composite alloys.
10.1016-j.physb.2018.02.003	-1		The liquid structure of CuxSn100-x (x = 0, 10, 20, 33, 40, 50, 60, 75, 80 and 100) alloys with atom percentage were investigated with resistivity and viscosity methods. It can be found from the resistivity data that the liquid Cu75Sn25 and Cu80Sn20 alloys had a negative temperature coefficient of resistivity (TCR), and liquid Cu75Sn25 alloy had a minimum value of -9.24 mu Omega cm K-1. While the rest of liquid Cu-Sn alloys had a positive TCR. The results indicated that the Cu75Sn25 atomic clusters existed in Cu-Sn alloys. In addition, the method of calculating the percentage of Cu75Sn25 atomic clusters was established on the basis of resistivity theory and the law of conservation of mass. The Cu75Sn25 alloy had a maximum volume of the atomic clusters and a highest activation energy. The results further proved the existence of Cu75Sn25 atomic clusters. Furthermore, the correlation between the liquid structure and the resistivity was established. These results provide a useful reference for the investigation of liquid structure via the sensitive physical properties to the liquid structure.
10.1016-j.physb.2018.07.031	-1		The effect of adding Zr at grain boundaries on the microstructure and plastic deformation of nanocrystalline copper has been investigated by molecular dynamics simulations. Zr addition broadens grain boundaries, and with increasing Zr contents, the disorder of grain boundaries increases and the mean potential energy of grain boundary atoms decreases. The strength of nanocrystalline copper increases with increasing Zr contents up to 4.1 at% and decreases with further increase in the Zr content. The CuZr alloy with 4.1 at% of Zr has the highest strength . The simulation results indicate that Zr addition improves the strength of nanocrystalline copper due to grain boundary strengthening, but excess Zr content results in a broadening of the grain boundaries that softens the CuZr alloys. These results suggest that there is a critical addition content when allying nanocrystalline metals with the addition of immiscible elements to improve their strength .
10.1016-j.physb.2018.10.021	4	transformation; martensite; martensitic; phase; shape; beta; memory; shape memory; temperature; temperatures; martensitic transformation; gamma; transformation temperatures; effect; thermal	A quaternary Cu80Al13Ni3Hf4 (wt%) shape memory alloy has been produced from high pure metallic powder through arc-melting method. Then homogenization been performed at 1173 K for 24 h and followed by a rapid cooling to salt-iced water. As a technique, one hour heat treatment at 773 K, 873 K, 973 K, 1073 K, and 1173 K, has been done to investigate some physical and structural properties. Some relevant measurements by using DSC, XRD, EDX-SEM, and Vickers hardness devices has been accomplished. While both DSC and XRD results showed that in room temperature all specimens were in austenite phase, but increasing the temperature of heat treatment make changes in the amount of precipitations presented in SEM micro-images, and hence led to a decrease in microhardness values. The sample with 1173 K heat treatment was the more stable phase compared to the other specimens, because a minimum values was obtained in calculation of Gibbs free energy and entropy.
10.1016-j.physb.2018.12.024	-1		In this work, martensite was made over the wide temperature ranges and the two forms of martensite morphology in Cu85.41Al9.97Mn4.62 shape memory alloy (SMA) were beta' and gamma' martensite phases. The SMA was characterized by the use of X-ray diffraction (XRD) and scanning electron microscopy (SEM) analyses. In order to fabricate the Schottky diode, Cu-Al-Mn alloy was used as a Schottky contact on p-type Si semiconductor substrate. Some of the crucial parameters for diodes such as ideality factor and barrier height values were obtained from electrical measurements. Illumination-dependent measurements showed that the fabricated device presents the behaviors of photodiode and photoconducting. Besides, it is found that the fabricated diode's structure is sensitive to illumination. Frequency-dependent measurements also indicated that the series resistance and interface state parameters are crucial to affect electrical characteristics of the fabricated diode. The experimental results showed that the fabricated Schottky device could be used in variety of optoelectronic applications.
10.1016-j.physb.2019.01.030	-1		We investigate the spinodal decomposition process in a melt-spun Cu-15Ni-8Sn alloy using X-ray diffraction (XRD), transmission electron microscopy (TEM), and electron diffraction analyses. In the XRD measurements, an aging treatment of more than 300 min at 350 degrees C was required to obtain the (200) sidebands. TEM observations of the melt-spun samples aged at 350 degrees C for 40, 60, and 300 min showed a modulated structure with a wavelength too small to be detected by TEM and aging for about 1200 min was required for the clear appearance of a modulated structure. The electron diffraction patterns showed only the disordered fcc phase with no satellite structures in the sample aged for 20 min at 350 degrees C, which implied that no spinodal decomposition occurred. Aging for 40 min at 350 degrees C was required before the super-lattice reflection of DO22 was observed. These experimental results indicate that the decomposition process in the melt-spun alloy was slow initially.
10.1016-j.physb.2019.01.032	-1		Using the ideal associated solution model, we analyze the impact of chemical interaction on thermodynamic properties and glass -forming ability of Cu-Zr-Al alloys. For two sections Cu0.33Zr0.67-Al and Cu0.5Zr0.5-Al, we calculate activities and thermodynamic functions of mixing in liquid state taking into account both binary and ternary chemical complexes. Our calculations relate thermodynamic properties of the melts with their chemical local order characteristics. The analysis of the results reveals that composition range corresponding to high glass-forming ability of Cu0.5Zr0.5-Al alloys correlates strongly with the range where CuZr associate dominates in the melt.
10.1016-j.physb.2020.412566	-1		Molecular dynamics (MD) simulations have been performed to investigate the mechanical properties (MPs) of Al-Cu-Ni based metallic glasses (MGs). The embedded atom method interaction potential has been employed for present MD technique. Due to brittle nature of Cu50Zr50 we studied the effect of Al (2 at%) on the MPs. Moreover, effect of Co and Ni (2 at%) on MPs of two component MGs (NiAl and FeCu respectively) is studied that are generated by melt quenching processes. The structure of samples is changed at melting and glass transition temperatures and the radial distribution function provides the appropriate outcomes for crystalline and glassy states. The mechanical analysis of three MGs has been investigated by employing uniaxial tensile deformation for a wide range of varying stain rates. It has been shown that the MPs of MGs are significantly expanded by the accumulation of Al, Co and Ni concentrations. It is revealed from the MD results that yield strength, Young modulus and ultimate tensile strength increase with an increase of stain rates at constant temperature. The computer software LAAMPS is used in order to investigate these MPs of MGs. In addition, computer software (OVITO) has been used for the visualization of crystalline and glassy states. The numerical outcomes obtained from MD method are found to be in satisfactory agreement with that obtained through the earlier known numerical MD results.
10.1016-j.physb.2021.412918	-1		In this study, glass forming composition (GFC) in Cu-Zr-Ti-Al system was predicted using thermodynamic guidelines involved model. The GFC was predicted by optimizing the enthalpy of chemical mixing and mismatch entropy in a statistically designed configurational entropy range. As designed composition Cu46Zr40Ti8.5Al5.5, close to eutectic point, was synthesized into metallic glass by melt spun technique. The amorphous nature of metallic glass was verified using XRD, DSC and TEM. The material was subjected to corrosion studies in simulated body fluids (SBF) at 37 ?C using electrochemical polarization technique. The material has exhibited better corrosion resistance in comparison to conventional biomaterials. Enhanced corrosion resistance is attributed to amorphous nature of the material and stable passive film predominately containing ZrO2, Al2O3 and AlOOH. Further, it was observed that the substitution of Cu with Al and Zr in Cu-Zr-Ti metallic glass enhances the corrosion resistance in SBF.
10.1016-j.physb.2021.413538	-1		Evolutionary algorithms and the particle swarm optimization method have been used to predict stable and metastable Cu structures between 0 and 2000 GPa that have not been discussed in previous studies, Cmcm phase is identified to be the most energetically competitive candidate. Density functional theory calculations illustrate that face-centered Cu atoms in (0 1 0), (0 1( -) 0) and (1 1 0) move along the 0 0 1 under the ultrahigh-pressure during the phase transformation from FCC (ambient pressure) to Cmcm (2000 GPa) structure. Phonon calculation further confirms the dynamical stability of this predicted structure, and the temperature dependence of electrical resistivity for Cmcm Cu will get reduced, predicted by phonon hardening with increasing pressure. The high-pressure structure still exhibits metallic behavior due to the finite electron DOS at the Fermi level, and the calculated elastic properties display superior bulk and shear modulus of Cmcm Cu with dramatic increase at 2000 GPa.
10.1016-j.physb.2022.414503	-1		This work used the arc melting technique to fabricate copper-iron and copper-nickel bulk alloys that were subsequently used to prepare spherical Cu-Fe and Cu-Ni nanoparticles through laser ablation in water. The average sizes measured using TEM were recorded as 34 nm and 20 nm of synthesized Cu-Ni and Cu-Fe nanoparticles, respectively. Further, XRD, VSM and DLS analyses were used to characterize the synthesized materials. The Cu-Ni nanoparticles showed higher antibacterial activities for the selected bacterial strains as compared to Cu-Fe nanoparticles. The Cu-Ni NPs showed slight mutagenic potential against S. typhimurium TA-98 strain and remained non-mutagenic against S. typhimurium TA-100 strain. Cu-Fe NPs show non-mutagenic potential against S. typhimurium TA-98 and S. Typhimurium TA-100 strains. The specific absorption rates of 5.04 and 2.18 W/g for the Cu-Ni nanoparticles and 9.74 and 7.39 W/g for Cu-Fe nanoparticles were recorded that show the potential usefulness of these bimetallic nanomaterials for magnetic hyperthermia.
10.1016-j.physb.2023.415352	-1		Based on our newly constructed W-Cu potential, pure W and W-Cu alloys are simulated with compression and shear deformation to reveal the fundamental mechanisms of the BCC-FCC phase transition. It is found that the BCC-FCC phase transition of W have two different mechanisms, i.e., BCC W transforms into FCC W by the Bain and Nishiyama-Wassermann (NW) paths under compression and shear deformations, respectively. Simulations also reveal that the addition of Cu promotes the BCC-FCC phase transition of W through the NW path, while it prevents the BCC-FCC phase transition through the Bain path . Moreover, the slips of 16aBCC[011]BCC(011)BCC and 6aBCC[011]BCC(011)BCC on both sides initially bring about the nucleation and growth of FCC W. The corresponding 1 topological models, volumetric strain, as well as the changes of lengths and total energies are also discussed to provide a fundamental understanding of the intrinsic mechanism of the BCC-FCC phase transition.
10.1016-j.physb.2024.416029	-1		Cu-Cr-Zr alloy is widely recognized as one kind of high-strength and conductivity Cu alloy, understanding the basic properties of compositional phases is crucial for preparing alloys with excellent properties. The structural, mechanical, thermodynamic, and electrical properties of Cu5Zr, CuZr, CuZr2, CuZr3 and ZrCr2 (CCZs) were systematically investigated by first-principles calculation in this paper. The results indicated that all optimized structures are mechanically and dynamically stable, and the hardest structure was confirmed as Cu5Zr in CCZs. Moreover, the overlapped phenomenon of band structures at Fermi energy level revealed these phases all possessed a metallic characteristic with conductor properties. Furthermore, the interaction of d orbit in Cu, Cr and Zr element is dominant in CCZs, and the magnitude of the electron orbital density of states of alloy elements reflects their contribution to the conductivity. The comprehensive results indicate that Cu alloys alloyed with Cr and Zr have excellent mechanical strength, conductivity, and thermal properties, laying the foundation for their applications in electrical, infrastructure, and welding fields.
10.1016-j.physb.2024.416466	14	strength; properties; conductivity; electrical; mechanical; cu-; grain; mpa; electrical conductivity; aging; precipitation; phase; mechanical properties; tensile; phases	The performance of metals in service is significantly influenced by grain boundaries(GBs). This study utilizes density functional theory and employs first-principles calculations to systematically look into the effects of 27 transition metal elements on copper's Sigma 5 [001](210) grain boundaries. Additionally, first-principles tensile methods are employed to quantitatively assess how alloying elements influence grain boundary strength . The fundamental reason behind the alloy atoms' influence on grain boundary(GB) strength is elucidated from the perspective of charge density variations. This research contributes to a deeper understanding of the behavior of transition metal elements at the Sigma 5[001](210) grain boundary on an electronic scale, consequently providing a theoretical framework for enhancing the strength of copper.
10.1016-j.physb.2025.416928	-1		The rapid advancement of technology allows devices to be designed at atomistic scales, creating a need for material characterisation at micro and nano levels. In this study, nanoindentation tests and MD simulations are compared to analyse the hardness, modulus of elasticity and surface deformation of CuNi alloys produced by casting. These methods are used to comprehensively investigate and compare the mechanical properties of alloys. The applicability of the simulation method to metal alloys is also evaluated. Nanoindentation tests revealed Em values between 101.89 GPa and 139.27 GPa, while MD simulations showed higher Em values ranging from 126.30 GPa to 186.34 GPa. Larger grain sizes in Cu-%10Ni alloy reduced the hardness to 2.40 GPa, while smaller grains in Cu-%20Ni alloy increased the hardness to 3.09 GPa. MD simulations allow real-time atomic-scale deformation observations, supporting empirical results and in agreement with the literature, and their applicability in metal alloys has been observed.
10.1016-j.physb.2025.417556	15	aging; strength; conductivity; electrical conductivity; electrical; mpa; treatment; strengthening; degrees; cu-; cold; precipitation; tensile strength; tensile; iacs	In order to study the effect of multi-element doping on the mechanical and electrical conductivity of copper alloys, first-principles calculations and experiments based on density functional theory were used to explore the coupling mechanism of multi-element doping on the improvement of mechanical and electrical conductivity of copper alloys at microscopic and macroscopic scales. The results show that the factors influencing the strength and electrical conductivity in copper alloys are as follows: 1) The complex phases (LaCu6, YCu5, ZrCu5) formed by doped elements and Cu, 2) the complex phases formed by the synergy of doped elements, and 3) the twin and dislocation structures induced by doping. The precipitated phase formed by La element has a lamellar structure, which improves the toughness of the alloy on the basis of losing part of the strength . Due to the high electrical conductivity of the precipitated phase LaCu6, the electrical conductivity of the alloy has increased by up to 23.8 %. The precipitated phase formed by Zr has a moderate size. It not only enhances the strength of the alloy but also improves the electrical conductivity, with the electrical conductivity increasing by up to 19.2 %. Y has a significant effect on enhancing the strength, but it has a negative impact on the electrical conductivity, with the electrical conductivity decreasing by at least 24.5 %.
10.1016-j.physb.2025.417586	-1		This research employed the molecular dynamics method to investigate the effects of composition on the mechanical characteristics of the CuCrCoFeNi alloy layer on crystalline Cu substrate during nano scratching. The mechanical properties were evaluated through common neighbor analysis (CNA), stacking faults (SFs), dislocations, coefficient of friction (mu), shear strain, and the number of wear atoms. The study provides important insights into the scratching mechanism by evaluating the effects of coating composition. The augmentation of Ni, Cr, and Fe content is associated with a decrease in the frictional coefficient and a reduction in the quantity of wear atoms. High-entropy alloys (HEAs) coatings rich in Ni, Cr, and Fe provide more effective protection of the Cu substrate.
10.1016-j.physb.2025.417884	-1		Multicomponent alloys of the Cu(Al)/Fe(Cr,Ni) system with Fe(Cr,Ni) alloy content of 10, 25, and 50 vol % were produced. Experimental studies and calculations of strength characteristics based on microstructural studies were obtained. The results of experimental studies of the structure and mechanical properties showed the formation of secondary Fe3Al, Cu3Al, and NiAl particles, leading to an increase in the yield strength from 273 MPa to 593 MPa and the tensile strength from 626 MPa to 818 MPa, as well as a decrease in plasticity by 18 %. Calculated data on the contributions of strengthening mechanisms in multicomponent Cu(Al)/Fe(Cr,Ni) alloys with different Fe(Cr,Ni) alloy contents showed that, depending on the Fe(Cr,Ni) alloy content, the strengthening mechanisms that contribute the most change from grain boundary to solid solution.
10.1016-j.physc.2007.03.461	-1		A biaxially textured Cu(200) tape was used as a substrate for YBCO coated conductors by cold rolling followed by recrystallization. heat treatment. In this work, we studied the influence of annealing conditions and final tape thickness on the recrystallization process. Phi (phi) scan and omega (omega) scan XRD revealed that the best in-plane and out-of-plane alignment of the Cu tape (thickness 100 pm), measured in terms of full width half maximum (FWHM) values of 6.64 degrees and 4.49 degrees, were obtained by annealing at 800 degrees C for 30 min. The texture of CeO2 buffer layer thermally-evaporated on the Cu tape was also analyzed.
10.1016-j.physc.2019.04.014	-1		Cu based alloy tapes with high strength, sharp Cube texture and non-ferromagnetism are the potential substrates for coated superconductors. Cu-Ni-W initial alloy ingot was prepared by melting and casting combined with forging and hot rolling. The effect of hot rolling on the formation of cube texture in Cu-Ni-W alloy is investigated. Compared with the texture after the forging process, the intensity of Cube texture in the hot rolled sheet is enhanced by hot rolling. The alloy sheets are fabricated by cold rolling and subsequent recrystallization annealing. The rolling textures and recrystallization textures of Cu-Ni-W alloy tapes are characterized. The cold rolled textures in the tapes with and without hot rolling are dominated by Copper and S textures. The sharp Cube texture develops during the recrystallization annealing, and the hot rolling is more beneficial for the formation of low angle grain boundaries. Moreover, the tape with sharp cube exhibits paramagnetic behavior at 77 K, which is desirable in alternating current.
10.1016-j.physleta.2006.01.012	11	glass; bulk; metallic; bulk metallic; gfa; bmg; glassy; metallic glass; ability; bulk metallic glass; amorphous; addition; crystallization; mm; glass-forming	Two metallic bulk glasses, Cu60Zr30Ti10 and Cu47Ti33Zr11Ni8Si1, with a diameter of 3 mm were prepared by copper mold casting method. Dilatometric measurement was carried out on the two glassy alloys to obtain information about the average nearest-neighbour distance r(0) and the effective depth of pair potential V-0. By assuming a Lennard-Jones potential, r(0) and V-0 were calculated to be 0.28 nm and 0.16 eV for Cu60Zr30Ti10 and 0.27 nm and 0.13 eV for Cu47Ti33Zr11Ni8Si1, respectively. It was found that the glassy alloy Cu60Zr30Ti10 was more stable than Cu47Ti33Zr11Ni8Si1 against heating from both experiment and calculation.
10.1016-j.physleta.2014.05.019	13	clusters; atomic; glass; atoms; composition; dynamics; metallic; icosahedral; glasses; simulations; molecular; cu-zr; molecular dynamics; metallic glasses; structural	In this study, the formation mechanism of polyhedron clusters in Cu50Ag50 binary alloy system consisting of 50 000 atoms has been investigated by using molecular dynamics simulations based on embedded atom method (EAM) during the rapid cooling processes. The cluster-type index method (CTIM) has been used to describe the evaluation properties of clusters and the structural development has been investigated by using radial distribution function (RDF). The simulation results show that the amorphous phase is formed by the main bonded pairs of 1551, 1541 and 1431 in the system, and ideal icosahedral (icos) cluster (12 0 12 0) and other basic polyhedron clusters, such as defective icos, Frank-Kasper, Bernal polyhedron, play a critical role under the rapid cooling conditions. The results of our simulations that have been disclosed show that high cooling rate favors the icos and defective icos clusters for model alloy system.
10.1016-j.physleta.2017.01.027	7	irradiation; shear; grain; ta; deformation; size; radiation; voids; nanocrystalline; simulations; similar; void; temperature; irradiated; boundaries	Molecular dynamics simulations are used to investigate uniaxial tension and compression of nanocrystalline copper with mean grain sizes of 3.8-11.9 nm. The simulation resifts show an apparent asymmetry in the flow stress, with nanocrystalline copper stronger in compression than in tension. The asymmetry exhibits a maximum at the mean grain size of about 10 nm. The dominant mechanism of the asymmetry depends on the mean grain size. At small grain sizes, grain-boundary based plasticity dominates the asymmetry, while for large grain sizes the asymmetry mainly arises from the pressure dependent dislocation emission from grain boundaries.
10.1016-j.physleta.2020.126418	-1		In this study, Cu-20wt.Sn alloy was produced by powder metallurgy (PM) method by using high purity element powders. The phases in the microstructure of the produced alloy were determined by XRD study. The phase transformation behaviour of the alloy was investigated by DSC and modelling method. Moreover, the Cu-20wt.Sn alloy system was modelled with molecular dynamics (MD) simulation based on modified Embedded Atom Method (MEAM). The radial distribution function (RDF) was calculated to determine the structural properties of system during the phase transformations. The experimental results showed that the transformation (alpha + delta) -> (alpha + gamma) occur at temperature above 500 degrees C. The simulation results showed that the phase transformation alpha + delta -> alpha + gamma occurs at 550 degrees C temperature. Our simulation results are in reasonable agreement with the experimental data.
10.1016-j.physleta.2025.130900	14	strength; properties; conductivity; electrical; mechanical; cu-; grain; mpa; electrical conductivity; aging; precipitation; phase; mechanical properties; tensile; phases	We investigate the role of grain boundary (GB) properties in mitigating irradiation-induced damage in pure Cu using molecular dynamics simulations. By analyzing cascade collisions and defect evolution, we demonstrate that GBs act as efficient sinks for point defects, with absorption rates strongly dependent on GB energy and interaction width . Higher-energy GBs exhibit superior defect absorption due to a thermodynamic driving force arising from reduced defect formation energies near GBs. Interstitials are absorbed preferentially over vacancies, attributed to their larger formation energy differences and wider interaction zones. A quantitative model is developed to predict defect absorption rates as a function of GB energy, interaction width, and temperature, providing a framework for designing radiation-resistant materials. These findings highlight the potential for tailoring GB properties to optimize defect absorption, with implications for applications in nuclear reactors and space environments.
10.1016-j.pnsc.2013.11.007	11	glass; bulk; metallic; bulk metallic; gfa; bmg; glassy; metallic glass; ability; bulk metallic glass; amorphous; addition; crystallization; mm; glass-forming	Ti-Cu-Zr-Fe-Nb ultrarine structure-dendrite composites were designed by inducing Nb and more Ti to a Ti-Cu-Zr-Fe glass-forming alloy composition and prepared by copper mold casting. The composite alloys consist of beta-Ti dendrites and uttrafine-structured CuTi2 and CuTi phases as well as a trace amount of glassy phase. The volume fraction of beta-Ti dendrites increases with the increase in content of Nb is acted as the beta-Ti phase stabilizer in the alloys. The composites exhibit high compressive yield strength exceeding 1200 MPa, maximum strength around 1800 MPa and low Young's modulus around 48 GPa. The plasticity of the alloys is strongly influenced by the volume fraction and morphology of the dendritic beta-Ti phase, and the compressive plastic strain was enlarged from 5.9% for the 4 at% Nb alloy to 9.2% for the 8 at% Nb alloy. The preliminary cell culture experiment indicated good biocompatibility of the composite alloys free from highly toxic elements Ni and Be. These Ti-based composite alloys are promising to have potential structural and biomedical applications due to the combination of good mechanical properties and biocompatibility.
10.1016-j.pnsc.2017.06.006	-1		Cu-Ni-Si alloys are widely used due to their good electrical conductivities in combination with high strength and hardness. In the present work, minor-alloying with M = (Cr, Fe, Mo, Zr) was conducted for the objective of further improving their hardness while maintaining their conductivity level. A cluster-plus-glue-atom model was introduced to design the compositions of M-alloyed Cu-Ni-Si alloys, in which an ideal composition formula [(Ni, Si, M)-Cu-12]Cu-3 (molar proportion) was proposed. To guarantee the complete precipitation of solute elements in fine d-Ni2Si precipitates, the atomic ratio of (Ni, M)/Si was set as 2/1. Thus the designed alloy series of Cu-93.75(Ni/Zr)(3.75)Si-2.08(Cr/Fe/Mo)(0.42) (at%) were arc-melted into ingots under argon atmosphere, and solid-solutioned at 950 degrees C for 1 h plus water quenching and then aged at 450 degrees C for different hours. The experimental results showed that these designed alloys exhibit high hardness (HV > 1.7 GPa) and good electrical conductivities (>= 35% IACS). Specifically, the quinary Cu93.75Ni3.54Si2.08(Cr/Fe)(0.42)Zr-0.21 alloys (Cu-3.32Ni-0.93Si0.37(Cr/Fe)-0.30Zr wt%) possess both a high hardness with HV = 2.5-2.7 GPa, comparable to the highstrength KLFA85 alloy (Cu-3.2Ni-0.7Si-1.1Zn wt%, HV = 2.548 GPa), and a good electrical conductivity (35-36% IACS).
10.1016-j.pnsc.2018.04.002	-1		Open-porous Cu-Sn-Ti composites are fabricated by the space holder sintering technique using carbamide particles as space-holder material. Generally, the mechanical properties of open-porous sintered composites, especially the flexural strength affect the machine tools wear significantly. In this paper, a back-propagation (BP) artificial neural network with genetic algorithm (GA) and particle swarm optimization algorithm (PSOA) was then employed to relate the composition parameters (pore size, porosity and concentration of molybdenum disulfide particles) to the flexural strength . Furthermore, a comparison of predicted and experimental results using GA-BP and PSOA-BP models was conducted and good prediction accuracy was obtained. The study showed that PSOA-BP models could achieve better prediction results in aspects of the higher convergence velocity, lower relative errors of the flexure strength utilizing GA-BP models. Finally, the high porosity and desired flexural strength were achieved by optimizing the input parameters of open-porous Cu-Sn-Ti composites.
10.1016-j.pnsc.2019.04.007	-1		The sintering behavior of Cu-9Al alloys prepared from die pressing of elemental powders was investigated. The experimental results and kinetic analysis showed the formation of three consecutive layers of Al2Cu, Al4Cu9, and AlCu phases, with Al2Cu appearing first in the initial solid phase sintering stage. A liquid phase formed in the intermediate stage, resulting from the eutectic reaction between Al and Al2Cu phases at 500 degrees C, which is 47 degrees C lower than the equilibrium reaction temperature. Swelling occurred when the liquid phase infiltrated the gaps between the copper particles, leaving pores at the original sites of Al particles and Al2Cu. In the final stage of sintering, the Al-rich phases (Al2Cu and AlCu) transformed to Al-poor phases (Al4Cu9 and alpha-Cu) in the temperature range of 500-565 degrees C. Al4Cu9 and alpha-Cu then transformed to AlCu3 (beta) above the eutectoid reaction temperature (565 degrees C), whereas AlCu3 transformed to alpha-Cu and eutectoid phases (alpha-Cu + Al4Cu9) during cooling. The pure copper transformed to AlCu3, and the pore volume decreased at 1000 degrees C. The microstructure study helps manipulate precisely the sintering process of Cu-Al alloys and optimize the microstructure with a high dimensional accuracy.
10.1016-j.pnsc.2019.08.009	11	glass; bulk; metallic; bulk metallic; gfa; bmg; glassy; metallic glass; ability; bulk metallic glass; amorphous; addition; crystallization; mm; glass-forming	The influence of Hf additions on the glass-forming ability (GFA), phase formation and mechanical properties of Cu50HfxZr50-x (x = 2,5,10,20 at%) alloys has been systematically investigated. We report on a distinct correlation between phase formation and GFA of Cu50Zr50-based alloys. Increasing additions of Hf reduce the thermal stability of the high-temperature B2 Cu(Hf,Zr) phase, while the thermal stability of the corresponding under-cooled melt is enhanced. The GFA of these alloy series gradually raises up to 10 at% Hf, whereas at 20 at%Hf, the GFA is drastically lowered, since the B2 Cu(Hf,Zr) phase becomes unstable and the precipitation of the low-temperature equilibrium phases is favoured. This interrelation determines the microstructure and results in the formation of Cu-Hf-Zr-based bulk metallic glass composites. These composites not only show appreciable macroscopic plastic strain, but also high yield strength .
10.1016-j.pnsc.2020.08.005	1	shape; memory; shape memory; damping; martensite; martensitic; damping capacity; transformation; capacity; strain; superelasticity; temperature; cu-al-mn; shape memory effect; effect	In this study, the low-cost production of Cu-Al-Mn-Fe shape memory alloy single crystals exceeding 46 mm by abnormal grain growth was realized only through annealing their cast alloys. The results show that the misorientation formed during annealing may be responsible for such abnormal grain growth process. It was confirmed that this misorientation resulted from the dissolution of bcc beta(FeAl) nanoparticles during heat treatment at a sufficiently temperature of approximately 1173 K. The rate of migration of the abnormal grain boundary was experimentally measured to be approximately 9.3 x 10(-5) m S-1 within 2 min of the commencement of abnormal grain growth . Additionally, the range of composition of the alloys that can lead to abnormal grain growth was determined. When the Cu-13.0Al-6.5Mn-3.2Fe single crystal close to the [100] direction was deformed to a prestrain of 12%, full shape recovery happened without any residual strain. At that time, the superelastic strain was approximately 9%. Such a superelastic characteristic remained nearly constant over 50 cycles, showing excellent fatigue resistance. The superelastic properties of the present Cu-13.0Al-6.5Mn-3.2Fe single crystal are compared to those of commercial Ni-Ti-based shape memory alloys. Therefore, it can be considered as a new kind of superelastic material having practical applications. The obtained results should be of great significance in the development of Cu-based shape memory alloys. Furthermore, it is expected that a similar microstructure can be designed for the production of more metallic single crystals.
10.1016-j.pnsc.2024.10.006	-1		The increasingly desirable mechanical and physical properties limits the application of traditional Cu-Cr alloys, and deserves the compositional design and processing optimization of Cu-Cr-Ti alloys. The effects of cold deformation and aging treatment on the microstructures and properties of the Cu-0.2Cr-0.08Ti alloys were investigated. The shapes of precipitates and evolution of dislocations in the specimens with increasing deformation amounts and aging times was uncovered, and the strengthening mechanisms of Cu-Cr-Ti alloys were elucidated by using TEM and HRTEM analysis. When the deformation amount is not higher than 40 %, the increased deformation amounts increases the dislocation density in the Cu-0.2Cr-0.08Ti alloy, promoting the formation of dislocation cell and dislocation tangles with small size. The precipitation of fine Cr particles coherent with Cu matrix is accelerated, accompanied by the enhancement of microhardness and electrical conductivity. The Cu-0.2Cr-0.08Ti alloy with 40 % deformation amounts after aging at 480 degrees C for 1 h has the optimal comprehensive properties, which is related to the increasing dislocation density, the refinement of Cu grains and the precipitation of Cr particles. The enhanced strength of Cu-0.2Cr-0.08Ti alloy with 40 % deformation amounts after aging at 480 degrees C for 1 his attributed to the solute strengthening of solute atoms, precipitate strengthening of fine Cr particles, dislocations strengthening and grain boundary strengthening mechanisms.
10.1016-j.poly.2017.05.001	-1		We present Density Functional Theory calculations results on ternary Cu8Zr4X icosahedral-like clusters and Cu11Zr6X2 superclusters, the dominant structural units of the Cu-rich eutectic metallic glass (Cu64Zr36), doped with X = Be, Mg, Al, Si, P, Nb, Ag. It came out that the presence of p electrons in both 13-atom clusters and superclusters (provided from the p electron type doping elements or, effectively, in other types of dopants via charge transfer from s to p and also from d top electrons) induces at certain energies Free-of-Bond planes. These Free-of-Bond planes could be viewed as analogs of slip planes increasing the ductility of the system. Moreover, we found that Zr atoms contribute with T(2)g or Eg electrons, occurring upon small topological alterations, which affect the Electronic Density of States, especially near the Fermi energy, thus permitting stress releasing. In addition, clusters with the dopant at the shell exhibit lower binding energies than those with the dopant at the center of a cluster. However, the differences in the binding energies are small, indicating that in metallic glasses these conformations may coexist and transform easily from one type of cluster to another, resulting in low energetic cost local atomic rearrangements.
10.1016-j.porgcoat.2018.11.027	2	corrosion; surface; film; electrochemical; films; spectroscopy; layer; current; solution; potential; resistance; composition; x-ray; ions; showed	A 3-mercapto-propyl-trimethoxysilane coating (PropS-SH) applied on Cu-Si-Mn bronze, patinated by liver of sulphur, was investigated as a non-toxic alternative to Incralac(circle), usually applied on outdoor artistic bronzes. Electrochemical testing was performed in synthetic acid rain. Exposure to temperature/UV cycles and accelerated corrosion test simulating unsheltered exposure to rainwater was also carried out. The exposed samples were characterised by FEG-SEM coupled with EDS on FIB cross-sections and XPS on free surfaces. The black patina without protective coating was scarcely protective against bronze corrosion and easily transformed into cuprous oxide. PropS-SH coating fully preserved the black patina microstructure and phase constituents (cuprous oxide and cuprous sulphide). The PropS-SH coating also resulted more protective than Incralac(circle) when aged under run-off conditions. Selective dissolution of copper from the silicon bronze alloy was observed on both uncoated and Incralac(circle)-coated bronze, leading to the formation of an internal Si-rich corrosion layer.
10.1016-j.porgcoat.2019.105444	2	corrosion; surface; film; electrochemical; films; spectroscopy; layer; current; solution; potential; resistance; composition; x-ray; ions; showed	We present a novel ternary composite coating consisting of graphene oxide (G0)-chitosan -silver on Cu-Ni Alloy with enhanced anticorrosive and antibacterial properties, produced using inexpensive and industrially scalable electrophoretic deposition (EPD) technique. Electrochemical studies showed a corrosion protection efficiency of similar to 99 % and a two order decrease in corrosion current density, with an optimum GO concentration of 0.025 wt% (0.5 g/l of chitosan and 1 mM silver nitrate). The results indicate that the GO retards the diffusion of corrosive ions to the substrate by increasing the detour path and minimizes the electron transport between the electrolyte and metal specimen while chitosan prevents the galvanic coupling of GO with metal surface. The amide linkage between the GO and chitosan matrix gave a good mechanical interlocking, with a crack free compact film. AFM images of composite film surface showed a wrinkled morphology, with an enhanced surface roughness of 56 +/- 6 nm. Microbiological analysis revealed an excellent antibacterial activity of the ternary composite, which offer promising applications in marine environment.
10.1016-j.powtec.2005.01.012	4	transformation; martensite; martensitic; phase; shape; beta; memory; shape memory; temperature; temperatures; martensitic transformation; gamma; transformation temperatures; effect; thermal	Scanning electron microscopy (SEM), neutron diffraction (ND) and thermal analysis studies were used to check the behaviour of powders of Cu-18 at% Li alloy in the temperature range between room temperature and 973 K under different types of atmospheres. After heating at 973 K the remaining lithium Content is about 15 at% and 13 at%, in the tests under argon and vacuum, respectively. In contrast, if the sample is heated in air or in nitrogen, the lithium content in solid solution in the alloy at temperatures of about 873 K is very low (3 at%). Consequently the alloy is in solid state at temperature as high as 1273 K. The heating of the alloy powders in nitrogen and in air, at atmospheric pressures, leads to the growth of lithium nitride, which was not expected.
10.1016-j.powtec.2013.07.019	16	wear; composite; composites; powders; milling; particles; powder; wt; sliding; friction; hardness; matrix; mechanical; surface; properties	Nanocrystalline Cu50Mg30Ni20 and Cu50Mg45Ni5 alloys were synthesized by mechanical alloying from mixtures of pure crystalline Cu, Mg and Ni powders using a Fritsch planetary ball mill with certain weight ratio of ball to powder. Structural evolution and thermal properties of these alloys were examined by X-ray diffraction (XRD), differential scanning calorimetry (DSC), scanning electron microscopy (SEM) and transmission electron microscopy (TEM). X-ray diffraction patterns were examined with the help of Fullprof program by employing Rietveld refinement technique. According to the present results, the crystallite size of Cu-Mg-Ni powders decreased with increasing milling time. Average crystallite size was calculated by three methods; Rietveld refinement technique, Debye Scherrer equation, TEM observation and, it was determined in the range of 10-20 nm. After 25 h of milling nanostructured three phases such as Cu-based solid solution (Cbs), Mg-0 Ni-85(0.15) and MgO were obtained. The lattice parameter of the Cbs phase varied from 3.61 to 3.66 A during different stages of milling from 5 to 25 h . DSC traces of the mechanically alloyed Cu-Mg-Ni powders showed two exothermic peaks after being milled for 10-15 h .
10.1016-j.powtec.2014.03.064	-1		A nanostructured disordered copper-iron-nickel alloy having the (Cu60Fe40)(70)Ni-30 composition was prepared through the mechanical alloying of the elemental powders in a high-energy ball mill under an argon atmosphere. The structural and morphological evolutions during mechanical alloying were investigated by X-ray diffraction and scanning electron microscopy. The patterns obtained were analyzed using the MAUD program. The transformation of the phase depended on the alloying time. The final product of the mechanical alloying process was nanocrystalline double-phase FCC-Cu(Fe,Ni) and BCC-Fe(Ni) solid solutions with a mean crystallite size in the range of few nanometers. The dislocation densities were found to be 6 x 10(15) m(-2), and the strain hardening caused by high-energy mechanical alloying was consistent with the concept of dislocations.
10.1016-j.powtec.2014.04.031	-1		The current work introduces a simple, convenient, and novel method for the synthesis of surface oxide free copper (Cu) nanoparticles. Electrical explosion of Cu wire in n-hexane containing oleic acid produced pure Cu nanoparticles smaller than 15 nm in diameter. The X-ray diffraction (XRD) patterns revealed that the oleic add-coated Cu nanoparticles maintained a highly pure Cu phase with no oxides for over three months after the synthesis. Analyses of Fourier transform infrared (FTIR) spectra indicated that the oleic acid was chemisorbed on the Cu surface via its oxygen atoms. In particular, an aggregation problem of the Cu nanoparticles with an increasing number of wire explosions was resolved by applying in-situ sonication process during the wire explosion.
10.1016-j.powtec.2014.08.040	-1		Mechanical alloying method was applied to fabricate Cr coating on Cu substrate at room temperature under ambient atmosphere, using a planetary ball mill with different milling durations. The formation of coating was a result of combined effects of mechanically induced plastic deformation, grain refinement, and deposition caused by the repeated collisions of milling balls along with powder particles. The microstructural features of the coatings were drastically affected by the treatment time. The results illustrated that at the selected processing conditions especially the rotation speed of 350 rpm and milling time of 7 h, a fully dense, uniform and metallurgically bonded coating was successfully fabricated on the substrate. The intermixing and the interdiffusion of elements at interface were critical for joining of the dissimilar materials under the ball collisions. The maximum hardness of the coatings reached 626 HV0.05 tested by Vickers hardness, showing a six times improvement upon the substrate. The friction and wear property were also improved with the reinforcing coating.
10.1016-j.powtec.2015.02.020	16	wear; composite; composites; powders; milling; particles; powder; wt; sliding; friction; hardness; matrix; mechanical; surface; properties	Nanocrystalline Cu-Fe-Co-Ni and [Cu-Fe-Co-Ni]-hBN powders composed of segregated particles and with lamellar and homogeneous structure were obtained by means of mechanical alloying. The powders were milled in planetary centrifugal mill and characterized by SEM, EDS, XRD, TEM and HRTEM. The results of investigation indicate that processing leads to formation of single-phase product with fcc lattice Cu-Ni-based solid solution. Addition of hBN into mixture results in deceleration of fcc solid solution forming and improving of mechanical properties. The hot-pressed samples made of mechanically alloyed at long duration Cu-Fe-Co-Ni and [Cu-Fe-Co-Ni]-hBN powders exhibit low strength due to high volume of nanopores. Mixing in ball mills preventing the occurrence of mechanical alloying is recommended to be used to fabricate binders for diamond- and cubic boron nitride cutting tools.
10.1016-j.powtec.2016.06.042	16	wear; composite; composites; powders; milling; particles; powder; wt; sliding; friction; hardness; matrix; mechanical; surface; properties	Carbon nanotubes (CNTs) based composite materials have gained a great deal of attention from both scientific and industrial community owing to the fascinating properties of CNTs. The present study reports the successful fabrication of composite materials based on copper (Cu) particles and carbon nanotubes (CNTs) using a planetary ball milling (PBM) technique with an optimized condition. Three different samples, namely (i) un-milled copper, (ii) un-milled copper with CNT and (iii) milled Cu with CNTs, have been used and were further processed using the PBM equipment in the presence of additional CNTs. The properties, in particular morphological and structural, of the prepared composites were comparatively analyzed. Various important parameters of PBM have been systematically explored in order to improve the properties of the composite materials. The results were systematically analyzed using scanning electron microscopy (SEM), X-ray diffraction (XRD) and field emission scanning electron microscopy (FESEM). The interface changes between Cu powder and CNTs, characterized by FESEM, revealed that the CNTs were weakly attached onto the surface of Cu when a low grinding speed was used, whereas the CNTs were strongly embedded onto the Cu surface by applying high rotation speed of PBM.
10.1016-j.powtec.2017.06.032	16	wear; composite; composites; powders; milling; particles; powder; wt; sliding; friction; hardness; matrix; mechanical; surface; properties	This paper investigates sliding wear behavior of copper matrix composites, reinforced by gamma-Cu5Zn8 intermetallic nanoparticles. In this research, first, gamma-Cu5Zn8 single phase intermetallic ingot was prepared; then, through mechanical milling method, copper based metal matrix composites with different amounts of high-strength gamma-Cu5Zn8 nano-particle were produced. Next, X-ray diffraction (XRD) test was carried out to analyze the progress of mechanical alloying. The investigated samples were formed by cold pressing at 800 MPa, followed by spark plasma sintering (SPS), and the samples were subjected to microstructural and mechanical characterization. Finally, the wear test with an experimental plan of load of 10 N and sliding speed of 0.5 m/s was conducted on Pin-On-Disk machine for a total sliding distance of 1000 m. The nanocomposites wear rate and the coefficient of friction decreased with the increase of reinforcement contents. The worn surfaces were analyzed via scanning electron microscopy (SEM), it was revealed that abrasive wear and delamination were the dominant mechanisms during the wear test.
10.1016-j.powtec.2017.07.036	-1		Ultrafine TiB2 particle (20 vol%) reinforced copper matrix composites were fabricated in-situ from Ti-B-Cu system through exothermic dispersion synthesis (XD). The reaction mechanism and mechanical properties of the composites were studied. It was found that when the reaction system was heated to 1373 K, Cu reacted with Ti to form the transient phase Cu4Ti, which continued to react with B to form ultrafine TiB2 particles as reinforcement agents. The apparent activation energy for these two reactions were calculated and found to be 453.7 KJ/mol and 1139.3 KJ/mol, respectively. Ultrafine TiB2 particles with the size of mostly 100 nm-500 nm were seen to distribute uniformly throughout the copper matrix. The ultimate tensile strength was measured and found to be 318 MPa, representing a 45% increase over pure copper. Moreover, the elongation to failure of the new composites was determined to be 4.4% at room temperature. The tensile fracture surface consists of many fine dimples, suggesting that the failure is of ductile nature. (C)2017 Published by Elsevier B.V.
10.1016-j.powtec.2017.08.019	10	composites; nanoparticles; strength; matrix; high; strengthening; particles; conductivity; composite; electrical; mpa; sintering; ods; grains; mechanical	In this work, Cu matrix composites reinforced with rutile-TiO2 nanoparticles were fabricated by a facile in-situ method, which involved the in-situ synthesis of TiO2-Cu composite powders by molecular-level mixing process and subsequent vacuum hot-pressing sintering of the as-obtained composite powders, leading to dense bulk composites with homogeneously distributed TiO2 nanoparticles. The influences of in-situ route on the microstructures, TiO2 distribution and mechanical properties of the composites were investigated. The results showed that the composite with 1.72 vol% TiO2 not only exhibited a high yield strength of 290 MPa which is about 1.6 times larger than that of pure Cu (110 MPa), but also possessed a high fracture elongation of 32% and an outstanding electrical conductivity' of 97% IACS, indicating the as-obtained TiO2/Cu composites possessing well-balanced mechanical properties arid electron conductivity. Moreover, the strengthening mechanism of TiO2 nanoparticles for the Cu matrix composites was analyzed based on the experimental results.
10.1016-j.powtec.2017.08.039	-1		Mechanical alloying is a promising method for preparing Cu-Cr alloy powder, while some troublesome challenges in cost and efficiency have yet to be solved. In this work, nano-scale Cu-Cr alloy powder was prepared by co-precipitation and advanced heat mechanical alloying (HMA) processes with low-cost raw materials. Results showed that the co-precipitation treatment by using ammonium hydroxide as the precipitant is an appropriate approach for manufacturing uniformly fine precursor. Box-Behnken design (BBD) was employed to investigate the Combined effects of milling temperature (T), milling duration (t) and ball-to-powder mass ratio (R) on the grain size of Cu-Cr alloy powder (GS) and to optimize the HMA process for fine alloy powder production. A second-order polynomial regression model was established and was verified by the analysis of variance (ANOVA), which shows good fit of the experimental data. Three-dimensional (3D) response surfaces were plotted to elucidate the main and interactive effects of the three parameters on the grain size of Cu-Cr alloy powder, and the optimum condition for HMA process was proposed.
10.1016-j.powtec.2017.11.037	-1		The purpose of this paper is to investigate the microstructure and properties of Cu-W alloys induced by high current pulsed electron beam (HCPEB) irradiation. The microstructural observation shows that craters were formed after 5 pulses of HCPEB irradiation. With the increasing numbers of pulses, these craters were further fused and eliminated, which results in an excellent surface finishing. In addition, the composition of melted layer was homogenized because of the inter-diffusion between Cu and W atoms. During the process of HCPEB irradiation, several modifications were formed, including Cu (W) solid solution, ultrafine grains, amorphous phase, and long-period superlattice phase, which significantly increased the microhardness of the surface. The results of sliding wear tests indicate that the HCPEB irradiated samples exhibited better properties as compared to that of the initial one, which was attributed to the ultrafine W particles embedded in the Cu matrix.
10.1016-j.powtec.2018.10.002	-1		Selective laser melting (SLM) using high laser power is a tendency in the future. In this paper, selective laser melting of Cu-10Zn alloy using high laser power of 1800 W has been performed. An optimal process parameters are obtained by studying the influence of process parametrs on the density of the SLMed samples. 99.97% relative density is achieved. Furthermore, the performances, such as microstructure, micro-hardness, mechanical properties and conductivity of Cu-10Zn parts using optimized parameters were investigated. The results show that the phase composition of SLMed Cu-10Zn is only alpha-Cu, the microstructure is elongated columnar grains which the size of building direction is much larger than that of other direction. A;< 1 00;> crystallographic texture exists, which results an anisotropy on micro-hardness. Finally, the ultimate tensile strength of 269.2 MPa, yield stress of 203.4 MPa, elongation of 26.4% and conductivity of 43.19%ICAS are achieved for the SLMed Cu-10Zn parts.
10.1016-j.powtec.2019.03.021	-1		Multi-walled carbon nanotubes (MWCNTs) and graphene synergetically reinforced Cu-graphite matrix composites with alloying elements and the rare earth element lanthanum were fabricated by powder metallurgy, and their mechanical properties were evaluated. An innovative solution for dispersing the solution into the MWCNTs and graphene was adopted by surface modification with gallic acid solution or rutin solution, instead of strong acid and base solutions, respectively. The interfacial bonding between MWCNTs or graphene and the copper matrix, and the particle distribution uniformity, were enhanced by mechanical alloying and freeze-drying. Nearly complete densification of the MWCNTs and graphene synergetically reinforced Cu-graphite matrix composites was achieved by hot-pressing and hot isostatic pressing sintering. The microstructure and mechanical properties of the composites indicated that the interfaces between the reinforcing phases and matrix were tightly bonded, confirming that the interface bonding between the MWCNTs, graphene, and copper matrix was mainly established as mechanical locks. The dominant strengthening mechanisms in the composites were the fine grain strengthening, load transferring, and solution strengthening, followed by dislocation strengthening.
10.1016-j.powtec.2019.11.122	-1		The in-situ reaction method for preparing metal matrix composites (MMCs) features the advantages like simple process, good combination of reinforcing phase and matrix, and it is especially suitable for the fabrication of TiCx reinforced copper matrix composites. In this study, the in-situ reaction method with CuxTi melt and dissolvable solid carbon was used to prepare the Cu-based TiCx composites. A uniformly dispersed TiCx particulate phase was obtained in the metal matrix, and they were tightly bonded. For the sample with the TiCx volume fraction of 26.2 vol%, the stoichiometry of the TiCx phase obtained was very close to 1, the flexural strength, the micro hardness and the thermal expansion coefficient reached 600 MPa, 360 HV and 12 x 10(-6) degrees C-1 respectively. The in situ reaction mechanism of carbon source particles in CuxTi alloy melt was analyzed, and the solid-liquid reaction kinetics of fine carbon source particles in CuxTi melt was mathematically modeled.
10.1016-j.powtec.2021.02.020	-1		In this work, the properties of novel Cu-Ag alloys reinforced with silver coated copper particles fabricated by hot pressing were systematically discussed for the first time. The effect of silver coated copper particle content on the microstructure, density, hardness, tensile strength and oxidation resistance of Cu-Ag alloys were investigated in detail. The silver coated copper particles were uniformly distributed within the copper matrix. With the increase of Ag coated Cu particle content, 100 wt% Cu-Ag alloy indicated denser microstructure than that of pure Cu. The tensile strength of 100 wt% Cu-Ag alloy was nearly 2 times higher than that of Cu samples. Electrical conductivity measured for Cu-Ag alloys was 24% higher than that of Cu samples. The oxidation resistance of Cu-Ag alloys increased with the silver coated copper particle content. In this context, the oxidation resistance of Cu-Ag alloys was 31% higher than that of Cu samples. In this work, the properties of novel Cu-Ag alloys reinforced with silver coated copper particles fabricated by hot pressing were systematically discussed for the first time. The effect of silver coated copper particle content on the microstructure, density, hardness, tensile strength and oxidation resistance of Cu-Ag alloys were investigated in detail. The silver coated copper particles were uniformly distributed within the copper matrix. With the increase of Ag coated Cu particle content, 100 wt% Cu-Ag alloy indicated denser microstructure than that of pure Cu. The tensile strength of 100 wt% Cu-Ag alloy was nearly 2 times higher than that of Cu samples. Electrical conductivity measured for Cu-Ag alloys was 24% higher than that of Cu samples. The oxidation resistance of Cu-Ag alloys increased with the silver coated copper particle content. In this context, the oxidation resistance of Cu-Ag alloys was 31% higher than that of Cu samples.
10.1016-j.powtec.2021.06.007	-1		Porous forms of Cu, Al and Cu/Al were prepared by powder metallurgy and the effect of process parameters on the microhardness, porosity and the cooling rate was examined. We report that although columnar powders are compacted more tightly under high compaction pressures, they also tend to form a connected pore network if a definite percentage porosity is maintained in the structure. Besides, the results show that the cooling rate dif-ferences between porous forms of Cu, Al and Cu/Al composites are not as dramatic as their bulk counterparts. Al-though the best cooling rate is achieved in pure Cu, the optimal condition in terms of cost-performance ratio was found to be the composite system with about 21.5% Al by response surface metholody based multi objective op-timization, even when performance was assumed to be 3 times more important than the cost.
10.1016-j.powtec.2021.11.014	-1		Carbon nanotubes reinforced copper-based composites (Cu/CNTs) had excellent physical properties and were widely used in industrial production and manufacturing. In this work, the mechanical properties and micro mor-phology of Cu/CNTs composites prepared by electromagnetic powder compaction (EMPC) at 25-200 degrees C were in-vestigated. Results showed that the relative density, hardness and compressive stress of Cu/CNTs compacts gradually increased as the temperature increased. The growth trend had an obvious turning point at 150 degrees C. The maximum relative density and compressive stress were 95.74% at 200 degrees C and 520.95 MPa at 150 degrees C, respec-tively. The micro morphology of the end faces and cross sections became denser. The temperature had a weak-ening effect on the compressive strain, but the opposite was true for compressive stress. The optimal temperature was 150 degrees C. The relationships between temperature and compressive stress and strain of Cu/CNTs composites were revealed. (c) 2021 Published by Elsevier B.V.
10.1016-j.powtec.2022.117571	-1		Tungsten carbide (WC) particles can be used as reinforcement to improve the mechanical and tribological properties of metal matrix. Herein, WC reinforced Cu-20Zn matrix composites were prepared. The mechanical and tribological properties of composites were also investigated. It was confirmed that the Cu3Zn solid solution was formed during the sintering process. Due to the solid solution and load transfer strengthening mechanism, the tensile and flexural strength were significantly improved. When the WC content was 30 wt%, the tensile and flexural strength were both increased by about two times compared with Cu-20Zn alloy. Additionally, the two-body abrasive and adhesive wear were gradually weakened with increasing WC content. When the WC content was 30 wt%, the composites showed low friction coefficient and wear rate. The formation of tribo-film, which was induced by tribo-oxidation reaction, was conceived to be responsible for the favorable lubricating properties.
10.1016-j.powtec.2024.120044	-1		The Laser Powder Bed Fusion (LPBF) manufacturing of dense Cu parts with near infrared conventional systems is still challenging due to the high reflectivity and thermal conductivity of the powder. In this paper, we investigate a novel approach to improve LPBF processability of Cu through the modification of particle surface properties. Pure Cu powders were coated with a thin layer of high-conductivity Ag by electrodeposition. The coated powder was also heat-treated at 500 degrees C and 600 degrees C to promote diffusion at the coating interface, producing different powder particle configurations. LPBF equipped with 200 W laser was used to produce bulk samples using pure Cu and Cu/Ag powder, which were comprehensively characterized by electron microscopy and X-ray diffraction. The Ag coating improved the material processability and density, forming a eutectic phase mixture able to heal pores and defects at the end of the solidification process.
10.1016-j.powtec.2025.120930	14	strength; properties; conductivity; electrical; mechanical; cu-; grain; mpa; electrical conductivity; aging; precipitation; phase; mechanical properties; tensile; phases	Cu-Cr-Nb, a high-strength, high-conductivity copper alloy for high-temperature applications, has gained importance in aerospace components used in extreme thermal environments. Laser additive manufacturing has become the predominant method for preparing Cu-Cr-Nb alloy components. In the typical additive manufacturing process, not all metal powder is utilized in the product formation, enabling reuse to reduce material costs effectively. This study investigated the recyclability of Cu-Cr-Nb powder in laser powder bed fusion and its impact on both the powder and the printed bulks. Compared to virgin powder, recycled powder exhibited extensive spatters, agglomerations, and a broadened particle size distribution, while its overall composition remained nearly unchanged. The increased oxygen content changed the chemical properties of the powder surface and resulted in a decrease in laser reflectivity. Findings indicated an expansion in the range of powder particle size distribution and an increase in oxygen content from 0.053 % to 0.143 % after six cycles, along with a 15.0 % decrease in reflectance. These alterations corresponded with a reduction in the melt pool's width-to-depth ratio, increased porosity, and lowered density, significantly affecting the relative ductility, whereas hardness and tensile strength remained largely unaffected. This research offers vital insights into employing recycled powder for copper alloys and also underscores the necessity for different recycling strategies across various alloy systems.
10.1016-j.rinp.2018.02.059	-1		In this work, Cu-TiC composites have been successfully prepared by reaction of soluble Ti and carbon coating TiC. Firstly, the ball milling of graphite and TiC mixtures is used to obtain the carbon coating TiC which has fine size and improved reaction activity. After adding the ball milled carbon coating TiC into Cu-Ti melts, the soluble Ti will easily react with the carbon coating to form TiC. This process will also improve the wettability between Cu melts and TiC core. As a result, besides the TiC prepared by reaction of soluble Ti and carbon coating, the ball milled TiC will also be brought into the melts. Some of these ball-milled TiC particles will go on being coated by the formed TiC from the reaction of Ti and the coating carbon and left behind in the composites. However, most of TiC core will be further reacted with the excessive Ti and be transformed into the newly formed TiC with different stoichiometry. The results indicate that it is a feasible method to synthesize TiC in Cu melts by reaction of soluble Ti and ball-milled carbon coating TiC. (C) 2018 The Authors. Published by Elsevier B.V.
10.1016-j.rinp.2018.05.011	-1		The Cu-TiC composites with non-stoichiometric TiC have been tried to prepare by melt reaction method in this work. It is confirmed that the TiC with different stoichiometries can be successfully prepared by changing the Ti/C ratio in raw material. When there is much excessive Ti in Cu melts, sub-stoichiometric TiC, such as TiC0.6, will be synthesized. However, the sub-stoichiometric TiCx, is not formed by direct reaction between Ti and graphite. In Cu-TiC composites prepared by melt reaction method, near stoichiometric TiCy prefer to be firstly synthesized by reaction between Ti and graphite. Then near stoichiometric TiCy will further react with Ti in the melts to form sub-stoichiometric TiCx (x < y) when there is much excessive Ti.
10.1016-j.rinp.2018.12.041	-1		The mechanical properties and microstructure of Cu-based diamond ultrathin sawing matrixes prepared using a cold pressing/sintering process were investigated. The experimental results show that the phases of Cu-based samples after sintering are mainly composed of a Cu substrate phase, Fe, (Cu, Sn), and Cu3.8Ni phases. When the pressure was increased to 187 MPa, Fe aggregation was generated, and this slowed the alloying and compaction of the Cu-based matrixes during the sintering process and weakened the corresponding mechanical properties. The densification, tensile strength, and elastic limit of Cu-based samples after sintering were best at a pressure of 187 MPa.
10.1016-j.rinp.2019.102319	16	wear; composite; composites; powders; milling; particles; powder; wt; sliding; friction; hardness; matrix; mechanical; surface; properties	In this work, we are reporting development of copper-highly strained stainless steel (HSSS)-tungsten carbide (WC) hybrid composites as well as their mechanical behavior and corrosion resistant properties (0.1M NaCl). Three types of Cu-HSSS-WC hybrid composites, having different quantity of HSSS (A1-1%, A2-2% and A4-4%), are prepared by stir casting and shaped in strip form. These strips are characterized by X-ray diffraction, scanning electron microscopy and energy dispersive X-ray analysis techniques along with micro-structure analysis. The corrosion resistances of the composites are determined by alternating current impedance measurements and Tafel polarization curves. The electrochemical results portray that composites can be arranged as per their corrosion resistance as: A4 > A2 > A1; which is same order of the composites as reported by hardness and ultimate tensile strength values. The results show that the prepared composites have greater hardness, ultimate tensile strength and corrosion resistance in comparison to bare copper.
10.1016-j.rinp.2019.102369	-1		In this work, Cu-TiC composites have been successfully prepared by adding Ti and carbon black powder mixture into Cu melts. The microstructure evolution of the composites with the change of Ti/C ratio and its mechanism has been investigated. It is found that when Ti and carbon black powder mixture is added into Cu melts, Ti will react with carbon black to form TiC, which makes the carbon black be wetted. Then the unreacted Ti will be dissolved and further reacted with the wetted carbon black to form more TiC. However, the formed TiC particles are dispersed difficultly and tend to aggregate into agglomerations. Increasing the Ti/C ratio is an effective method to improve the distribution of TiC. It is found that, comparing with the Cu-4Ti-1C, non-stoichiometric TiCx with smaller x which has the better wettability with Cu melts can be synthesized in the Cu-5Ti-1C and Cu-6.67Ti-1C. As a result, TiC particles are more uniformly distributed in the prepared Cu-Ti-C composites with higher Ti/C ratio.
10.1016-j.rinp.2019.102494	-1		In this work, ZrB2 particles have been in-situ synthesized in the Cu melts using Cu-B master alloy as the starting material. It is found that the non-uniformly distributed ZrB2 particles in the prepared as-cast composites tend to aggregate into agglomerations and this trend is more pronounced with the ZrB2 content increasing. In addition, the size of hexagonal plate-like ZrB2 whose diameter ranges from less than 1 mu m to more than 10 mu m accompanied by the thickness ranging from about 0.5 mu m to 2 mu m shows an uneven appearance. The increasing ZrB2 contents can give rise to the higher hardness values of 160-205% of the original pure Cu. However, the electrical conductivity which is about 52.9% IACS to 76.8% IACS will be severely affected. Besides, the decreased friction coefficient from 0.6 to 0.4 and the gradually declining lost mass of the samples indicates the better wear resistance property with increasing ZrB2 contents.
10.1016-j.rinp.2019.102593	8	hot; deformation; strain; strain rate; dynamic; hot deformation; recrystallization; dynamic recrystallization; flow; rate; flow stress; compression; constitutive; degrees; stress	Hot compression tests of Cu-Ni-Si alloy with high Ni and Si contents were performed at the deformation temperatures of 750-950 degrees C, and the strain rates of 0.01-10 s(-1) on a Gleeble-3800 thermo-mechanical simulator. The critical conditions for dynamic recrystallization (DRX) of Cu-Ni-Si alloy were obtained by processing the collected data and combining with the inflection point of theta-sigma curve with the minimum value criterion of -partial derivative theta/partial derivative sigma-sigma curve. There was a certain correlation between the critical strain (epsilon(c)) and the peak strain (epsilon(p)), that was, epsilon(c)/epsilon(p) = 0.723, and the functional relationship between epsilon(c) and Z parameter was epsilon(c) = 1.05 x 10(-3)Z(0.)(059). The average recrystallized grain size under various deformation conditions was measured, and the DRX grain growth model of Cu-Ni-Si alloy was established as d(DRX) = 5650.4(epsilon)over dot(-)(0.12891)exp(-73142/RT).
10.1016-j.rinp.2019.102672	-1		In this work, we study the effect of silver inclusions on the mechanical behavior of Cu-Ag nanocomposites during nanoindentation using Molecular Dynamics Simulations. Pure Cu and Cu matrices containing Ag inclusions of different sizes, located at various depths under the surface, are investigated. The results of simulations show that the presence of silver inclusion influences the strength of the material. Indeed, the hardness of Cu substrate containing an Ag inclusion is lower than that of pure Cu. In addition, for a given inclusion radius, the hardness decreases with decreasing inclusion depth beneath the indenter. Furthermore, our results also showed that, at a fixed inclusion depth, hardness increases as the inclusion radius decreases and the maximum hardness value is obtained for an inclusion radius and depth of 17.5 A and 60 A, respectively.
10.1016-j.sab.2021.106128	2	corrosion; surface; film; electrochemical; films; spectroscopy; layer; current; solution; potential; resistance; composition; x-ray; ions; showed	A series of quantitative micro X-ray fluorescence (mu-XRF) analyses was performed on a) corroded surface, b) stripped-patina area and c) polished cross section of twenty-five archaeological copper alloys from Iran in order to check the viability of quantitative XRF data for the classification of ancient copper alloys. The limits of detection and quantification and, also, the precision and accuracy of the analytical data were measured using twelve certified reference materials (CRM). The compositional data obtained through these three approaches were statistically evaluated comparing with the compositional data on the same samples obtained by the inductively coupled plasma-optical emission spectroscopy (ICP-OES). We demonstrated that the corroded surfaces are depleted in Ni and Zn and enriched in Pb, Sn and As. Also, we suggest that although mu-XRF quantitative compositional data collected from the corroded surfaces may result in misleading information, the areas with the lowest Sn concentration may represent the closest compositional data to the absolute quantity of Cu, Zn, As and Pb in ancient copper alloys. Moreover, it is shown that the quantitative mu-XRF data obtained from the stripped-patina surface and those from the polished cross sections are comparable with the ICP-OES compositional data and can be confidently used for determining the diversity and technology of ancient copper alloys.
10.1016-j.scitotenv.2024.172645	2	corrosion; surface; film; electrochemical; films; spectroscopy; layer; current; solution; potential; resistance; composition; x-ray; ions; showed	In this paper, the relationship between the pitting corrosion formation of B30 copper-nickel (Cu-Ni) alloy and the metabolism of sulfate -reducing bacteria (SRB) was investigated. Combined with the influence of temperature during the actual operation of the cooling systems, the evolution law of the alloy passivation film was analyzed, and the mechanism of SRB promoting the accelerated development of B30 Cu-Ni alloy pitting corrosion was revealed. The results show that SRB significantly promoted the pitting formation and development of B30 Cu-Ni alloy. The maximum pitting depth was 3.9 mu m in the sterile system and 15.3 mu m with SRB, which was 3.9 times higher than that of sterile system. The loose porous Cu 2 S film formed by SRB metabolites and copper matrix was easily penetrated by corrosive anions, which promoted copper dissolution and led to pit nucleation. The sulfide adsorbed on the surface prevented or delayed the passivation of B30 Cu-Ni alloy by blocking the adsorption site of O atom, and the corrosion nuclei continued to grow. The non -uniformity caused by the film peeling accelerated the longitudinal development of pitting corrosion, and the expansion and coalescence of adjacent pits caused the transverse development of pitting corrosion. Temperature had a certain influence on the SRB and the formation of B30 Cu-Ni alloy passivation film. The passivation film was formed rapidly at 50 degrees C with poor quality and the passivation property of Cu 2 O film was weakened. With the increase of temperature, the pitting potential of sterile system negative shifted from 0.447 to 0.360 V (vs. SCE), while SRB system from 0.340 to 0.198 V (vs. SCE), and the pitting resistance decreased. The passivation film with defects and the Cu 2 S reduced the barrier efficiency of the film and accelerated the pitting corrosion of B30 Cu-Ni alloy.
10.1016-j.scp.2023.101340	2	corrosion; surface; film; electrochemical; films; spectroscopy; layer; current; solution; potential; resistance; composition; x-ray; ions; showed	In terms of green chemistry, the use of the use of expired drugs has recently gained attention as sustainable corrosion inhibitors due to their biodegradability, environmental friendliness, low cost, and easy availability. This paper aimed to evaluate the protective action of expired Bepotas-tine-B on Cu-Zn alloy in simulated cooling water (SCW) using weight loss (WL), Potentiodynamic polarization (PDP), electrochemical impedance spectroscopy (EIS), surface morphology analysis and computer modeling methods, including density functional theory (DFT) and molecular dynamic simulations (MS).The variables concentration, reaction temperature, and pH of an expired drug were examined. The electrochemical results demonstrated that the expired Bepotastine-B is a mixed-type inhibitor that blocks both the anodic and cathodic potentials, which exhibited high inhibition. The corrosion rate falls as the Bepotastine increases and increases as the temperature rises. The drug's adsorption on Cu-Zn alloy follows the Langmuir isotherm model. The examination of surface morphology (SEM/EDX) indicated a formation of an insoluble complex and a fine film of in-hibitor, which effectively hinders Cu-Zn alloys from deteriorating, covering the surface. These findings confirmed the formation of an adsorbed layer by the Bepotastine-B molecules hindered the dissolving of Cu-Zn alloys. The inhibitory impact of Bepotastine-B, which investigated, theo-retically using DFT and the computational results align well with the results obtained from exper-imental inhibition efficiencies. The inhibition efficiency (IE) improved with raising Bepotastine-B concentration. The maximum IE of 94.6% has been achieved at 300 mg/L. The combination of experimental and computational approaches enhanced our understanding of the corrosion inhibition mechanism and underscored the potential of Bepotastine-B as a sustainable, and effective corrosion inhibitor for Cu-Zn alloy in this medium at dissimilar temperatures. These findings can serve as a useful guideline for future research aimed at investigating the inhibitory impact of ex-pired drugs as a green one.
10.1016-j.scriptamat.2004.06.016	-1		We investigate Cr filaments in heavily drawn Cu-10 wt%Cr-3 wt%Ag in situ composite wires as a function of temperature and time. The filaments undergo a capillarity-driven shape change from a bamboo morphology with grain boundary grooves to complete spherodization. We interpret the results in terms of analytical models.
10.1016-j.scriptamat.2004.11.004	-1		The effects of an electrical field on recrystallization of Cu have been investigated. A 12degrees off exact (112) [11 (1) over bar] copper single crystal was rolled to 80% reduction. Samples cut from the deformed material were then annealed for 1 h at temperatures of between 200 degreesC and 400 degreesC. For each temperature, samples were annealed either with or without the presence of an electfical field of intensity 1500 V/cm. The microstructures were investigated in the longitudinal plane by using the electron backscatter pattern technique. Results show that the application of an external electric field might promote the grain growth rate. and also promote the formation of Sigma3 twin boundary.
10.1016-j.scriptamat.2005.11.077	11	glass; bulk; metallic; bulk metallic; gfa; bmg; glassy; metallic glass; ability; bulk metallic glass; amorphous; addition; crystallization; mm; glass-forming	One-centimeter diameter fully glassy rods have been obtained using copper mold casting at the Cu44.25Ag14.75Zr36Ti5 composition. Starting from the ternary glass Cu60Zr33Ti7 With a critical size of 3 mm, our search strategy in the quaternary composition tetrahedron enabled us to obtain the 10 mm glass by testing only about 40 alloy compositions. The dramatic increase in the glass-forming ability is attributed to the effects of Ag in stabilizing the liquid.
10.1016-j.scriptamat.2006.01.048	11	glass; bulk; metallic; bulk metallic; gfa; bmg; glassy; metallic glass; ability; bulk metallic glass; amorphous; addition; crystallization; mm; glass-forming	Cu-based bulk metallic glass (BMG) composites containing in situ TiB particles were successfully fabricated. The reinforcing TiB particles with a size of 5-10 mu m are uniformly distributed in the amorphous matrix. The particles have a good bonding to the matrix with a reaction layer. The BMG composites exhibit an obvious ductility with a plastic strain of 2% for the 17.5 vol.% TiB sample due to the suppression of shear band propagation and the generation of multiple shear bands during compressive testing. The hardness of the materials is increased from HV543 for monolithic BMG to HV650 for 23.6 vol.% TiB-containing BMG composite.
10.1016-j.scriptamat.2007.03.008	11	glass; bulk; metallic; bulk metallic; gfa; bmg; glassy; metallic glass; ability; bulk metallic glass; amorphous; addition; crystallization; mm; glass-forming	The effect of replacement of Zr/Hf with Gd or Y in Cu46Zr47Al7 and Cu50Hf42.5Al7.5 alloys has been investigated. Phase separation into Cu-Gd-rich (or Cu-Y-rich) and Cu-Zr-rich (or Cu-Hf-rich) amorphous phases occurs during cooling when the Gd (or Y) content is above 15 at% in Cu-(Zr, Hf)-(Gd, Y)-Al alloys. In particular, it was realized that the plasticity in bulk metallic glass with heterogeneity can be enhanced either by tailoring the combinations of the constituent elements or by controlling the cooling rate.
10.1016-j.scriptamat.2007.04.018	4	transformation; martensite; martensitic; phase; shape; beta; memory; shape memory; temperature; temperatures; martensitic transformation; gamma; transformation temperatures; effect; thermal	An anomalous internal friction phenomenon was observed during the reverse martensitic transformation of a polycrystalline CuAl-Ni-Mn-Ti shape memory alloy, i.e. negative internal friction appeared during the transformation, when frequency is relatively low due to the interaction between the martensitic variants with positive and negative loss elastic modulus. The latter can be stabilized by applied stress when their orientation is unfavorable for the applied stress because of the constraint of austenite in a single growth direction.
10.1016-j.scriptamat.2007.08.007	-1		The evolution of the thermal conductivity and the coefficient of thermal expansion as a function of the alloying content of boron and chromium in the copper matrix in Cu-X/diamond composites is presented. In both systems a transition from weak matrix/diamond bonding to strong bonding is observed, the latter leading concomitantly to high thermal conductivity (> 600 W m(-1) K-1) and a low coefficient of thermal expansion (< 10 ppm K-1).
10.1016-j.scriptamat.2007.10.001	11	glass; bulk; metallic; bulk metallic; gfa; bmg; glassy; metallic glass; ability; bulk metallic glass; amorphous; addition; crystallization; mm; glass-forming	Starting from the two binary bulk glass formers in the Cu-Zr system, we systematically investigated the compositional dependence of glass formation, thermal, elastic, and mechanical properties in the Cu-Zr-Ag ternary bulk glassy alloys. Both CU(50-x)-Zr50Agx and CU(64-x)Zr36Agx series show a good combination of high glass-forming ability and high Poisson's ratio. However, compressive plastic deformation was only observed in CU(50-x)Zr50Agx series and the possible underlying mechanism is discussed.
10.1016-j.scriptamat.2008.07.005	0	solidification; phase; magnetic; magnetic field; undercooling; field; liquid; separation; peritectic; immiscible; cu-; dendrite; phase separation; microstructure; primary	The paper reports a novel method for investigating the kinetics of liquid-phase separation, which combined conventional electromagnetic levitation with a superconducting magnet. The experiments on Cu50Co50 alloys revealed a singular size distribution for the minor Cu-rich phase in a Co-rich matrix under a magnetic field of 2 T, which differed from a bimodal distribution under a zero field. Such an effect of the magnetic field is similar to that of reduced gravity during parabolic flights.
10.1016-j.scriptamat.2008.07.008	-1		The chemical composition of Cu-rich precipitates from body-centered Fe-Cu is treated in the framework of classical nucleation theory. Although the analysis is based on purely thermodynamic arguments and does not account for kinetic effects, it is demonstrated that, when taking into account the composition dependence of interfacial energy and driving force, the predicted equilibrium composition of nanometer-sized Cu precipitates differs substantially from the equilibrium composition of large precipitates. Evidence is provided to the experimental finding that early Cu precipitates contain substantial amounts of Fe.
10.1016-j.scriptamat.2008.07.040	-1		X-ray diffraction (XRD) experiments and first-principles calculations were employed to investigate the martensitic transformation products formed upon rapid cooling of the CuZr-B2 phase. Candidate intermetallic compound structures were selected, and calculations show that CuZr-B11 (CuTi prototype), CuZr-B27 (FeB), CuZr-B19' (NiTi) and CuZr-B33 (BCr) are more stable than the B2 phase at 0 K. Computed XRD patterns, based on first-principles calculations, were compared with experimental XRD measurements. The results indicate that the CuZr martensite consists of the CuZr-B33 and CuZr-B19' phases.
10.1016-j.scriptamat.2008.08.041	-1		Contrary to the common belief that many-fold twins in nanophase materials are due to the action of significant external stresses, we report molecular dynamics simulations of 5 nm grain size Cu samples annealed at 800 K showing the formation of fivefold twins with no external pressure. The structure of the many-fold twins is remarkably similar to those we have found to occur under uniaxial shock loading in nanocrystalline NiW. The formation mechanism of the many-fold twins is discussed.
10.1016-j.scriptamat.2008.11.015	11	glass; bulk; metallic; bulk metallic; gfa; bmg; glassy; metallic glass; ability; bulk metallic glass; amorphous; addition; crystallization; mm; glass-forming	Plastic deformation of Cu Zr (Al,Ti) bulk metallic glass (BMG) composites induces a martensitic phase transformation from the B2 to the B19' CuZr phase. Addition of Ti to binary Cu Zr increases the temperature above which the B2 CuZr phase becomes stable. This affects the phase formation upon quenching in Cu Zr Ti BMG composites. The deformation-induced martensitic transformation is believed to cause the strong work hardening and to contribute 10 the large compressive defortmability with plastic strains up to 15%.
10.1016-j.scriptamat.2009.02.026	-1		A new copper matrix composite reinforced with Zr2Al3C4 particulates was successfully fabricated by powder metallurgy method. In the whole reinforcing range, Cu/Zr2Al3C4 Composite possesses comparable electrical conductivity and better mechanical properties than those of Cu/graphite composite, which was widely accepted as the electro-contacting material. The high conductivity was attributed to the formation of a continuous copper network in the composite, while the high strength and modulus of Zr2Al3C4 ceramic led to a notable improvement in the mechanical properties of the composite.
10.1016-j.scriptamat.2009.03.060	-1		We studied the role of thermal spike in nanocrystallization of Cu50Zr45Ti5 metallic glasses after 1 MeV Cu ion irradiation at room temperature. Nanocrystals of Cu10Zr7 and CuZr2 phases are formed after the ion irradiation. The study suggests that thermal spike formation and subsequent quenching are too fast to allow direct structural transformation in the damage cascade regions. The overall irradiation effects are caused by enhanced atomic mobility due to increased excessive free volume.
10.1016-j.scriptamat.2009.05.018	-1		Compression testing shows that at low-oxygen levels (240 ppm) the Cu(49)Hf(42)Al(9) glass deforms predominantly by shear and is quite tough . Specimens with higher oxygen levels (1700 ppm) have oxygen-containing dendrites in an amorphous matrix and show no plasticity. Importantly, the dominant fracture mode is not shear but local tensile failure. Although there is a slight reduction in the toughness of the glassy matrix, the severe embrittlement is primarily because of the brittle dendrites that facilitate crack initiation and propagation.
10.1016-j.scriptamat.2009.07.005	-1		We report a shape memory effect in Cu-Zn thin films grown by electrodeposition on pyrolytic graphite from pyrophosphate-based electrolytes. Cu-Zn films showing a martensitic transformation could only be obtained after the optimization of thermal annealing parameters such as annealing temperature, Zn vapour pressure and fast quenching. By means of controlling the Zn vapour pressure during annealing using a bulk reference Cu-Zn alloy, the chemical composition of the films could be adjusted and the martensitic transformation temperatures of the films could be tuned.
10.1016-j.scriptamat.2009.08.002	13	clusters; atomic; glass; atoms; composition; dynamics; metallic; icosahedral; glasses; simulations; molecular; cu-zr; molecular dynamics; metallic glasses; structural	Al-27 nuclear magnetic resonance spectroscopy was used to probe the atomic-scale structural evolution in Cu46Zr47-xAl7Gdx (x = 0, 1, 5) glassy alloys with minor Gd addition. It was found that the local symmetry of atomic clusters around Al atoms is the closest to being spherical at 1 at% Gd addition. Interestingly, this also corresponds to the Gd content for which the glass-forming ability (GFA) reaches a maximum, suggesting that the GFA of these glassy alloys may be dominated by their local geometric structure.
10.1016-j.scriptamat.2009.08.008	-1		We report on density functional theory results referring to the bonding characteristics and the strengthening induced by small Al additions in representative icosahedral Cu7Zr6 and rhombic dodecahedral Cu9Zr6 clusters and their interconnections. We found that the presence of Al modifies seriously the interactions with its surroundings, introducing strong covalent-like bonding that may resist strain, thus explaining experimental observations referring to the strengthening effect of metallic glasses upon small Al additions.
10.1016-j.scriptamat.2009.11.012	-1		A method is presented for the simultaneous measurement of relative grain boundary energy and all five macroscopic grain boundary degrees of freedom in leaded copper. When compared to the Wynblatt-Takashima model, results suggest a lowered boundary energy when there are equal broken-bond densities on either side of the boundary.
10.1016-j.scriptamat.2011.06.043	-1		We report a non-monotonous behavior of the hardness of amorphous Cu-Zr films as a function of composition, by applying a combinatorial deposition and nanoindentation method with unparalleled compositional resolution. Distinct peaks in hardness were identified at particular compositions to correlate well with the previously reported density peaks. Our results not only facilitate the discovery of new glass-forming alloys, but also raise the possibility of developing bulk metallic glasses with enhanced plasticity and/or ductility for engineering applications.
10.1016-j.scriptamat.2012.05.018	-1		Precession electron diffraction (PED) is used to acquire orientation information in Cu-Nb nanolamellar composites fabricated by accumulative roll bonding (ARB). The resulting maps quantify the grain size, shape, orientation distributions and interface planes in the vicinity of nanometer-thick deformation twins. The PED-based texture results compare favorably with bulk textures provided by neutron diffraction measurements, indicating uniformity in the ARB Cu-Nb texture. Additionally, {112}(Cu)parallel to{112}(Nb) interfaces are present, suggesting that ARB techniques can lead to stable interfaces with a special crystallography.
10.1016-j.scriptamat.2012.07.018	-1		A CuCrZr alloy has been processed by equal channel angular pressing and annealing. Changes of microstructure have been analysed using thermoelectric power measurements, which are very sensitive to the amount of solute as well as other defects introduced during processing. Severe plastic deformation of solutionized material leads to significant increases in the amount of solute, which leads to significantly more precipitation on ageing. Such factors must be taken into account in any interpretation of final microstructures and mechanical properties.
10.1016-j.scriptamat.2012.10.036	6	grain; deformation; strain; strength; dislocation; cu-; tensile; size; ecap; grain size; sfe; ductility; hardening; high; stress	As the slip mode plays an important role in dislocation evolution and mechanical behavior, the effects of the slip mode on the high-cycle fatigue behaviors of ultrafine-grained (UFG) Cu and Cu-Zn alloys were evaluated. It is found that the fatigue limits can be improved largely by changing the slip mode to hinder dynamic recovery and recrystallization through the addition of Zn in comparison with UFG Cu with wavy-slip mode because of the serious strain localization and microstructural instability of the latter.
10.1016-j.scriptamat.2012.10.037	-1		The viscous flow behavior of Cu55Zr30Ti10Co5 metallic glassy samples was investigated on heating by a mechanical testing machine in accordance with the phase transformations taking place in the alloy. Phase transformations were studied by various methods, including differential calorimetry and electron microscopy. It was found that glassy samples demonstrated a relatively low viscosity of similar to 10(9) Pa s and did not lose their ability to be deformed under a relatively low stress of 5 MPa during the crystallization process until complete crystallization had occurred, thus producing in situ glassy/crystal composites.
10.1016-j.scriptamat.2013.10.014	-1		We report the formation of deformation twins in a nanocrystalline Cu-25 at% Ni alloy with medium stacking fault energy via the propagation of Sigma 3{11 2} incoherent twin boundaries (ITBs) that are nucleated from grain boundaries. This deformation twinning process does not generate net macroscopic strain since the Burgers vectors of the three partial dislocations on three successive {1 1 1} planes comprising an ITB sum to zero. The moving direction of ITBs determines the occurrence of twinning or detwinning in nanocrystalline materials.
10.1016-j.scriptamat.2013.12.006	-1		Carbon nanotube (CNT)- and Fe-p-reinforced copper-matrix composites were successfully fabricated by laser induction hybrid rapid cladding to enhance simultaneously their thermal conductivity and mechanical properties. The microstructure and properties depended on the interaction between CNTs and Fe-p. When the CNT content was 2.6 wt%, smaller Fe-p and CNTs were uniformly embedded in Cu-rich matrix. The composites exhibited attractive properties including thermal conductivity (197 W m(-1)K(-1)), hardness (429HV(0.2)), coefficient of friction (0.11) and wear rate (5.3 x 10(-16) m(3) N-1 m(-1) lap(-1)).
10.1016-j.scriptamat.2014.06.012	-1		This study focuses on the microstructural refinement induced by ball milling in individual metals and Cu-based metal mixtures. A phenomenological model is developed to rationalize the kinetics of grain size reduction. A discontinuous change of the average grain size is predicted to occur in very small powder volumes during each collision. The final average grain size and the rate of grain size reduction are shown to vary with the composition depending on the difference in hardness between the metals.
10.1016-j.scriptamat.2015.01.015	-1		The tensile behaviors of Cu50Zr50 metallic glass (MG) films with the same cooling history as a function of film thickness are systematically studied by molecular dynamics simulations. It clearly reveals that with decreasing film thickness, a transition from the localized deformation to the non-localized deformation indeed occurs in Cu50Zr50 MG films, which might be a general phenomenon for all MGs. The thickness-dependent deformation mode change observed here, is then reasonably explained by the Griffith crack-propagation criterion.
10.1016-j.scriptamat.2015.10.010	7	irradiation; shear; grain; ta; deformation; size; radiation; voids; nanocrystalline; simulations; similar; void; temperature; irradiated; boundaries	Using intrinsic solute segregation in alloys, the compressive stress in a series of Cu(Ni) thin films has been studied. The highest compressive stress was noted in the 5 at%Ni alloy, with increasing Ni concentration resulting in a subsequent reduction of stress. Atom probe tomography quantified Ni's Gibbsian interfacial excess in the grain boundaries and confirmed that once grain boundary saturation is achieved, the compressive stress was reduced. This letter provides experimental support in elucidating how interfacial segregation of excess adatoms contributes to the post-coalescence compressive stress generation mechanism in thin films.
10.1016-j.scriptamat.2015.12.012	-1		Molecular dynamics simulations were employed to investigate the specimen thickness-dependent tensile behavior of a series of Cu(x)Z(100-x) (x = 20, 40, 50, 64 and 80 at%) metallic glass (MG) films, with a particular focus on the critical thickness, tc, below which non-localized plastic flow takes place. The simulation results reveal that while the transition occurs in all the alloys examined, t(c) is sensitive to the composition. We rationalize t(c) by postulating that the strain energy stored in the sample at the onset of plastic deformation has to be sufficient for the formation of shear bands. The composition-dependence of t(c) was found to correlate with the average activation energy of the atomic level plastic deformation events.
10.1016-j.scriptamat.2016.01.012	7	irradiation; shear; grain; ta; deformation; size; radiation; voids; nanocrystalline; simulations; similar; void; temperature; irradiated; boundaries	Radiation-enhanced precipitation of W has been investigated in dilute Cu-W alloys. While spherical W precipitates are stabilized during irradiation below similar to 300 degrees C and above similar to 600 degrees C, irradiation at 500 degrees C results in the formation of nanorods. Furthermore, use of two-step irradiations, first one at 600 degrees C followed by one at 500 degrees C, indicates that the morphological transformation is reversible. The stabilization of W nanorods is rationalized using a model introduced by Frost and Russell to explain size stabilization of precipitates formed during irradiation, but extended here to consider precipitate morphology.
10.1016-j.scriptamat.2016.07.008	-1		Cu-Hf and Cu-Cr-Hf alloys have been subjected to severe plastic deformation applying equal channel angular pressing and high pressure torsion. Grain boundary diffusion was measured in a temperature interval between 423 K and 570 K using the radiotracer technique with the Ni-63 isotope as tracer. The microstructure evolution examination using scanning electron microscopy showed no structural changes during diffusion annealing. Diffusion profiles in pressed samples reveal the occurrence of a percolating porosity, whereas no such porosity could be detected in the twisted samples. The determined diffusion coefficients correspond to those in severely plastically deformed Cu alloyed with Pb or Zr. (C) 2016 Published by Elsevier Ltd on behalf of Acta Materialia Inc.
10.1016-j.scriptamat.2016.08.006	-1		Most deformation twins in nanocrystalline metals were reported to produce zero macroscopic strain via either random activation of partials or cooperative slip of three partials. In their coarse-grained counterparts, deformation twins produce a net macroscopic strain and change the grain shape since a twin forms via the glide of a single twinning partial dislocation on successive {111} planes driven by Peach-Koehler force. Here, we report the formation of large scaled zero-macrostrain deformation twins in coarse-grained copper with medium stacking fault energy. The responsible formation mechanism is proposed and its effect on twinning or detwinning processes is discussed.
10.1016-j.scriptamat.2016.10.022	10	composites; nanoparticles; strength; matrix; high; strengthening; particles; conductivity; composite; electrical; mpa; sintering; ods; grains; mechanical	A bulk solid solution Cu-5Ag alloy consisting of nanotwins and nanograins was prepared by means of dynamic plastic deformation at liquid nitrogen temperature. Continuous precipitation of Ag occurs in the nanotwins which exhibit higher thermal stability than the nano-grains upon annealing. A tensile strength of 870 MPa and an electrical conductivity of 78% International Annealed Copper Standard are achieved in the annealed nano structure Cu-5Ag alloy which is strengthened with nanotwins and nanoscale precipitates.
10.1016-j.scriptamat.2016.10.033	7	irradiation; shear; grain; ta; deformation; size; radiation; voids; nanocrystalline; simulations; similar; void; temperature; irradiated; boundaries	Superior radiation tolerance has been experimentally examined in nanotwinned metals. The stability of nanotwinned structure under radiation is the key factor for advancing the application of nanotwinned metals for nuclear reactors. We thus performed in situ radiation tests for nanotwinned Cu with various twin thicknesses inside a transmission electron microscope. We found that there is a critical twin thickness (10 nm), below which, radiation induced detwinning is primarily accomplished through migration of incoherent twin boundaries. Detwinning is faster for thinner twins in this range, while thicker twins are more stable. Published by Elsevier Ltd on behalf of Acta Materialia Inc.
10.1016-j.scriptamat.2017.02.009	-1		Normally immiscible 57 wt% Cu-43 wt% Cr compounds were mechanically alloyed by means of high pressure torsion with large and controllable strains. A strain-saturated state in 57 wt% Cu-43 wt% Cr bulk was achieved after 100 rotations deformation (effective strain 1360), with a stable grain size of 13.7 nm and largest solubility of 32 wt% Cu in Cr matrix. The phase fraction change between face-centered cubic and body-centered cubic due to Cu dissolution during continuous deformation was captured and accurately calculated, indicating a negative exponential phase change mode. A phenomenological dissolution mechanism based on the kinetic competition between mixing under sustained external forcing and thermal diffusion induced decomposition was proposed, which was well compliant with the phase evolution observed from experimental results. (C) 2017 Acta Materialia Inc. Published by Elsevier Ltd.
10.1016-j.scriptamat.2017.02.010	6	grain; deformation; strain; strength; dislocation; cu-; tensile; size; ecap; grain size; sfe; ductility; hardening; high; stress	The tensile tests were conducted to investigate the influence of short-range order (SRO) on the mechanical properties and deformation microstructures in coarse-grained Cu-Mn alloys with high stacking fault energies. Tensile testing results demonstrate that a good strength-ductility match in Cu-Mn alloys can be achieved by increasing degree of SRO (namely increasing Mn content). With increasing SRO of alloys, the deformation micromechanisms were gradually transformed from wavy slip of dislocations to planar slip of dislocations and deformation twinning, resulting in a synchronous improvement of strength and ductility of Cu-Mn alloys.
10.1016-j.scriptamat.2017.03.016	4	transformation; martensite; martensitic; phase; shape; beta; memory; shape memory; temperature; temperatures; martensitic transformation; gamma; transformation temperatures; effect; thermal	The effect of grain size on thermal hysteresis is studied in ribbons and thin strips obtained by rapid solidification techniques. Results show a strong increase of the hysteresis width when the grain size is below similar to 100 mu m. This effect is attributed to frictional work spent to accommodate the different martensitic variants in a zone close to grain boundaries, which constitutes an energy barrier proportional to the grain boundary area. A model for describing this effect based on thermodynamics and fitted experimental data is proposed.
10.1016-j.scriptamat.2017.03.024	-1		The strain-rate sensitivity along the load-unload experiments on fine-grained pure Cu and Cu-Ni alloys are presented. For grain sizes lying in the range of 1-10 mu m in pure Cu, Cu16at%Ni and Cu50at%Ni, an elevated rate sensitivity at the first few percent of plastic strain is observed. At this elasto-plastic transition, a substantial hysteresis during unloading is developed corroborating to the Bauschinger effect in the fine-grained materials. The strain rate sensitivity results are analyzed along the load-unload response of the materials. A dislocation-based phenomenological model is developed to describe the experimental observations.
10.1016-j.scriptamat.2017.04.012	-1		Cu and Ta are co-deformed at 673 K by the accumulative roll-bonding technique up to 8 passes. At an equivalent von Mises strain (epsilon(vm)) of similar to 2 the deformation is bifurcated into shear accommodated by the 'soft' Cu, and plane-strain by the 'hard-but-ductile' Ta. This is attributed to transitions occurring collectively at epsilon(vm) similar to 2 in crystallographic texture, partitioning of recovery and recrystallization, and the nature of interfaces as elucidated by orientation relations, Hall-Petch behavior and manifestation of instabilities at higher strain. (C) Published by Elsevier Ltd on behalf of Acta Materialia Inc.
10.1016-j.scriptamat.2017.04.017	1	shape; memory; shape memory; damping; martensite; martensitic; damping capacity; transformation; capacity; strain; superelasticity; temperature; cu-al-mn; shape memory effect; effect	Columnar-grained Cu-Al-Mn shape memory alloy (SMA) exhibits excellent superelastic fatigue properties at high strain amplitude, and its functional fatigue life reaches above 10(3) cycles at tensile strain of 4%-10%. As the increase of loading-unloading cycle number, the transformation stress and superelastic recovery rate decrease. The decay coefficient of recovery rate is about 1.4. Fatigue cycles for Cu-Al-Mn SMAs can be divided into four stages according to the significant changes of superelasticity: plateaus stage, rapid attenuation earlier stage, rapid attenuation later stage, functional incapacitation stage. The columnar-grained Cu-Al-Mn SMA shows larger range of stable superelasticity than other polycrystalline counterparts.
10.1016-j.scriptamat.2017.04.025	7	irradiation; shear; grain; ta; deformation; size; radiation; voids; nanocrystalline; simulations; similar; void; temperature; irradiated; boundaries	This article reports the impact of nanovoids on macro-properties and its underlying physical mechanism in nanotwinned Cu films with nanovoids synthesized via magnetron sputtering. The results indicate the resistivity due to nanovoids is proportional to void porosity at 4 K and the film hardness induced by nanovoids is proportional to void density in the slip plane while independent of void sizes. The ratio of hardness to resistivity is thus able to be improved by tuning nanovoids based on above findings. These findings will definitely provide references for the future study on the improvement of materials' properties synthesized by sputtering deposition techniques.
10.1016-j.scriptamat.2017.08.034	6	grain; deformation; strain; strength; dislocation; cu-; tensile; size; ecap; grain size; sfe; ductility; hardening; high; stress	Fully recrystallized ultrafine-grained (UFG) pure Cu specimens were fabricated by high-pressure torsion (HPT) and controlled annealing. The recrystallized UFG Cu with a minimum mean grain size of 0.51 pm showed high yield strength, good ductility, obvious yield drop and large Liiders strain during tensile test. The mechanical behavior of the Cu specimen became sensitive to the change in the grain size from 0.2 pm to 4.2 pm. The continuous transitions of yield behavior and Luders deformation with grain sizes were discussed.
10.1016-j.scriptamat.2017.09.031	-1		Three Cu-alloys (CuSn5, CuZn5, CuZn30) have been selected, to study the influence of solutes on the saturation grain size after high pressure torsion as well as the resulting mechanical properties with an emphasis on strain rate sensitivity. Compared to each other, the alloys exhibit either similar stacking fault energies or similar solid solution strengthening, allowing a separation of both parameters. The results indicate that the saturation grain size correlates with the solid solution strengthening but not with the stacking fault energy. Moreover, a reduced strain rate sensitivity with reduced grain size is observed, which is attributed to the microstructural stability.
10.1016-j.scriptamat.2018.04.027	-1		Alloying effect on tensile ductility of nanostructured Cu-X (X = Zr and W) thin films was studied in comparison. Both Zr and W atoms segregated at grain boundaries (GBs) and increased the GB cohesion energy, leading to similar increase of ductility in as-deposited Cu-X films. After annealing treatment, however, changes in ductility showed different alloying effect: the Cu-Zr one increased while the Cu-W one decreased when compared with their as-deposited counterparts. This discrepancy was rationalized by different microstructural evolution that intergranular CuZr amorphous layer was produced in the Cu-Zr film while intergranular W grains were formed in the Cu-W one.
10.1016-j.scriptamat.2018.06.025	-1		Uniform macroscopic samples of nanoporous metal with high deformability have so far been limited to precious metals such as Au, Pd and Pt. Here we propose nanoporous Copper-Nickel (npCN) as a nanoporous base metal that can be made with mm dimensions and exhibits significant deformability. NpCN forms a uniform bicontinous network structure with feature sizes that can be controlled from 13 to 40 nm by thermal annealing. Continuous compression tests confirm ductile deformation behavior accompanied with a high strength compared to macroporous Cu- and Ni-foams with similar solid fraction.
10.1016-j.scriptamat.2019.01.038	-1		A ternary immiscible nanostructured Cu-Al-Nb alloy was fabricated by friction stir processing of mechanically compacted pellets. Subsequently, aging was carried out at 563 K for various times. The material exhibited hardness of similar to 43 +/- 0.1 GPa in the peak-aged condition (aging for 6 h), which is remarkable among Cu-based ternary immiscible alloys. The excellent strength of the material is attributed to Hall-Petch strengthening due to the extremely refined nanocrystalline structure, coupled with precipitation strengthening due to a uniform distribution of nano-scale Al- and Nb-rich precipitates or clusters, as confirmed by X-ray diffraction and microstructural characterization.
10.1016-j.scriptamat.2019.02.011	1	shape; memory; shape memory; damping; martensite; martensitic; damping capacity; transformation; capacity; strain; superelasticity; temperature; cu-al-mn; shape memory effect; effect	The polycrystalline Cu-13.0AI-7.7Mn-0.6Cr cast alloy consists of the Heusler L2(1) (Cu(2)AIMn) parent and the disordered body-centered cubic A2(Cr) precipitate due to bcc phase separation. These two phases are completely coherent When annealing cast alloy, the abnormal grain growth occurs. It is closely related to the dissolution of A2(Cr) particles and the formation of a continuous misorientation gradient within the matrix grains. The results show that the single crystal dose to [100] orientation shows large superelastic strain of 8.5%. Furthermore, the single crystal almost remains full superelastic characteristic after 1.2 x 10(3) cycles, showing enhanced fatigue resistance.
10.1016-j.scriptamat.2019.02.014	-1		In this work, we use nanocalorimetry to characterize the diffusion kinetics of Cu-Zr and Ni-Zr glass-forming alloys in both the solid state and the super-cooled liquid state, covering a temperature range from 0.67T(g) to 1.49T(g). We find that diffusion in the solid state follows Arrhenius behavior, while the kinetics in the super-cooled liquid state is well described by a fragility-based model that takes into account breakdown of the Stokes-Einstein relationship between the diffusivity and viscosity. The current work uses a single experimental technique to map out the kinetics of diffusion over a broad temperature range in both states.
10.1016-j.scriptamat.2019.02.040	6	grain; deformation; strain; strength; dislocation; cu-; tensile; size; ecap; grain size; sfe; ductility; hardening; high; stress	We report that the uniform and stable microstructure essentially ameliorate the cyclic softening of the ultrafine-grained (UFG) Cu prepared by friction stir processing (FSP) and then enhance its low-cycle fatigue properties. In lieu of the fatigue-induced grain coarsening, dislocation and grain boundary (GB) activities play crucial roles in accommodating the cyclic plasticity. In addition, the protrusion and small cracks near the GB regions rather than shear bands are main surface damage morphologies that lead to its final fatigue failure.
10.1016-j.scriptamat.2019.02.046	7	irradiation; shear; grain; ta; deformation; size; radiation; voids; nanocrystalline; simulations; similar; void; temperature; irradiated; boundaries	Radiation induced void swelling is widely observed in a variety of metallic materials. Here, by using sputtering deposition technique, we have introduced faceted nanovoids into Cu films. In-situ Kr ion irradiation was subsequently performed at room temperature to investigate the evolution of nanovoids. Most nanovoids found to shrink gradually with increasing dose. Irradiation induced high-density vacancy clusters exist mostly in the form of stacking fault tetrahedrons. Phase field modeling reveales that void shrinkage arises from biased absorption of interstitials. These findings provide insights to the physical mechanisms of radiation response of nanovoids in metallic materials.
10.1016-j.scriptamat.2019.07.019	-1		Surface area and fluid permeability are two key properties of porous metals in many applications. However, it is extremely difficult to achieve both high surface area and fluid permeability in conventional porous metals. In this work, we developed a synergetic manufacturing process by combining space holder and dealloying methods and produced bulk hierarchical porous Cu samples containing micro-pores and nano-pores. The hierarchical porous Cu possesses high electroactive, real and Brunauer-Emmett-Teller surface areas of 0.11, 7.02 and 10.62 m(2)/g, respectively, a high permeability of 9.5 x 10(-10) m(2) and a low form drag coefficient of 400 m(-1).
10.1016-j.scriptamat.2019.10.050	-1		We observed very high thermal stability (after annealing at 600 degrees C for 1 h) of the near-surface layers of ultrafine grains in the 99.9995 wet (5N5) purity Cu processed by high-pressure torsion. We attributed this extraordinary thermal stability of ultrafine-grained microstructure to the nitrogen-filled nano-sized pores that pinned the grain boundaries. Our study reveals that a combination of severe shear strain and surface attrition causes the capture of N-2 molecules in the near-surface layer of the deformed metal from the ambient atmosphere. This phenomenon may play an important role in formation of percolating porosity in metals processed by severe plastic deformation.
10.1016-j.scriptamat.2020.03.028	-1		A combination of conventional calorimetry, ultra-fast scanning calorimetry and resistive heating gives access to heating rates exceeding 6 orders of magnitude allowing to probe crystallization kinetics and mechanisms in a Cu-Zr-Al metallic glass. Continuous-heating-transformation and double-peak timetemperature-transformation diagrams are constructed and related to the formation of glass-crystal composites with enhanced ductility. The metastable B2-CuZr phase becomes dominantly formed at a heating rate of similar to 10(2) K s(-1) and higher. A critical heating rate to bypass crystallization is similar to 10,000 K s(-1). For isothermal annealing at >850 K, only one crystallization event is detected; for lower temperatures, a complex two-step transformation occurs.
10.1016-j.scriptamat.2020.04.044	-1		In this work, the mechanical properties and microstructural evolution of a recently developed immiscible medium-entropy alloy (Al-15(CuFeMn)(85), at%) at 77 K were investigated. Nanoscale deformation twinning was observed in both Cu-rich and Fe-rich grains. Twin-mediated martensitic transformation from Cu-rich beta(1) phase to beta(1)' martensite was occurred during tensile deformation at 77 K. The phase transformation into a stronger phase generates high plastic incompatibility between the constituent phases, resulting in high strength and work hardening by hetero-deformation-induced extra strengthening. The measured hetero-deformation-induced stress demonstrates the dominant hetero-deformation-induced strengthening mechanism at 77 K.
10.1016-j.scriptamat.2020.07.014	7	irradiation; shear; grain; ta; deformation; size; radiation; voids; nanocrystalline; simulations; similar; void; temperature; irradiated; boundaries	Nanocrystalline Cu-Ta is among the most successfully developed nanostructured alloys involving microstructural design, synthesis, characterization, and testing. However, the interplay of direct and indirect thermal stability mechanisms is still unclear. In this work, mechanically alloyed Cu-10at%Ta was characterized with atomic-resolution electron microscopy to identify thermal stability mechanisms. A new mechanism involving athermal core-shell particles that were coarsening resistant was discovered after annealing between 100-800 degrees C up to 1000 h . Evidence suggests that oxide amorphous shells decreased the phase boundary energy thereby reducing the thermodynamic driving force for particle growth and indirectly maximizing thermal stability of Cu(Ta) grains.
10.1016-j.scriptamat.2020.08.036	6	grain; deformation; strain; strength; dislocation; cu-; tensile; size; ecap; grain size; sfe; ductility; hardening; high; stress	Stress reduction creep tests conducted on a Cu-Cr-Nb alloy (GRCop-84) at 923 K have confirmed local dislocation climb to be the rate-controlling deformation mechanism. The activation energy of creep was measured to be consistent with that of self-diffusion in Cu matrix. An internal back stress of approximately -9 MPa was identified to act on the rate-controlling dislocations, which is believed to be the sum of the back stress for dislocation-particle interaction and the forward stress for dislocation-dislocation interaction. This back stress, however, does not lead to a true threshold in the framework of thermally activated dislocation motion.
10.1016-j.scriptamat.2020.113695	7	irradiation; shear; grain; ta; deformation; size; radiation; voids; nanocrystalline; simulations; similar; void; temperature; irradiated; boundaries	An undercooled liquid-phase (L-phase) can undergo a first order configurational phase transition to either a crystal phase (X-phase) or a metastable, configurationally heterogeneous, rigid glassy phase (G-phase). To investigate the underlying mechanism of the L-G transition, we employ molecular dynamics simulations to study G-phase formation in a binary Cu-Ag system. We find that G-phase formation is driven by the reduction of local distortion energy arising from deviatoric strains in the liquid phase and demonstrate its local distribution. Reduction of distortion energy contributes over 80% of the latent heat of the L-G transition, suggesting that condensation of spatially varying random elastic fields in the liquid is primarily responsible for the first order L-G transition. By applying this analysis to crystallization and G-phase formation in elementary Ag, we show that deviatoric strain energy is the dominant driving force for the L-G and L-X transition also in the case of the pure metal.
10.1016-j.scriptamat.2021.113741	-1		A nanoprecipitates induced dislocation pinning and multiplication strategy is proposed for designing Cu alloys with high strength, plasticity and conductivity. That is, the nanoprecipitates act as obstacles and sources of dislocations. Additionally, the precipitation purifies the Cu matrix to guarantee the conductivity. To verify this strategy, dense dislocations and nanoprecipitates are introduced to a Cu-Fe-Ti alloy by solution treatment, rolling and aging. In-situ transmission electron microscopy straining and molecular dynamics simulations demonstrate that nanoprecipitates not only hinder the dislocation glide but also facilitate the dislocation multiplication, resulting in a tensile strength of 590 MPa combined with a uniform elongation of 6% of the alloy. The purification of the Cu matrix by the precipitation leads to an electrical conductivity of 69% IACS. Hence, this strategy paves a new avenue for developing high strength, high plasticity and high conductivity alloys.
10.1016-j.scriptamat.2021.114114	-1		The applications of dealloyed nanoporous metals are usually hindered by their slow rate of synthesis, the limited sample dimensions, and the poor mechanical stability due to the presence of native cracks. We report that these obstacles can be overcome by combining dealloying with spark plasma sintering. Centimeter-sized nanoporous Cu samples were prepared by spark plasma sintering of dealloyed nanoporous Cu particles. The obtained bulk nanoporous Cu samples are free of major cracks, and exhibit hierarchical porous structures with structure size of-250 nm at lower level of hierarchy and relative density varying between 0.29-0.57. Because of the size effect on ligament strength and the elimination of native cracks, these nanoporous Cu samples are stronger than monolithic nanoporous Cu (with cracks) and microporous Cu of similar density. We anticipate that this approach will improve the performance and broaden the application of nanoporous metals, of which the synthesis rate, sample dimensions and microstructure are no longer dependent entirely on dealloying procedure.
10.1016-j.scriptamat.2021.114214	7	irradiation; shear; grain; ta; deformation; size; radiation; voids; nanocrystalline; simulations; similar; void; temperature; irradiated; boundaries	Phase boundaries in multiphase alloys govern defect interaction and chemical intermixing across different phases during plastic deformation. Dynamic interaction of defects with phase boundaries in multiphase alloys, especially for immiscible alloys, has generated more research interest in recent years. Here, we describe a novel approach for carrying out in-situ TEM shear deformation to directly observe interfacial microstructural evolution of a Cu-Nb alloy. A unique double shear specimen geometry is microfabricated by a focused ion beam technique to apply shear deformation upon push loading inside the TEM. From the real-time observation, we discover that the phase boundary with a zigzag morphology effectively blocks stacking faults nucleated in a Cu grain from slipping into a Nb grain. Meanwhile, the Cu phase bears the most plastic deformation through slip or twinning mechanisms. This work sheds light on understanding the shear deformation and the behavior of phase boundaries in multiphase alloys during shear deformation.
10.1016-j.scriptamat.2021.114218	-1		The liquid-liquid phase separation (LLPS) behavior was investigated in Cu-Fe alloys that consisted of 60 wt% or 80 wt% Cu and balance iron, without or with addition of 1 wt% Zr. Both Zr-free alloys clearly showed LLPS at metastable spinodal temperatures prior to gamma-Fe nucleation, whereas Zr-added showed gamma-Fe phase evolution without LLPS. Addition of Zr was highly effective to activate gamma-Fe nucleation by decreasing the mixing enthalpy and also accelerating heterogeneous nucleation. A combination of thermal instrumental analysis and classical nucleation theory yielded an effective assessment made of LLPS behavior below the liquidus temperature of Cu-Fe alloys. Furthermore, it was possible to control the solidification mechanism of Cu-Fe alloy by zirconium addition.
10.1016-j.scriptamat.2021.114344	7	irradiation; shear; grain; ta; deformation; size; radiation; voids; nanocrystalline; simulations; similar; void; temperature; irradiated; boundaries	In this work, a nanocrystalline (NC) Cu-10at%Ta alloy is irradiated with helium at different temperatures to assess the stability and effectiveness of Ta nanoclusters in trapping helium and suppressing swelling. Advanced microstructural characterization of the room-temperature irradiated specimens indicated the presence of small He-bubbles (-1-2 nm) at the peak damage depth mainly at the core and along the interface of Ta nanoclusters with Cu matrix. Few bubbles were found along grain boundaries, with much smaller bubbles homogenously distributed within the copper lattice. High-temperature irradiation exhibited bubbles of-3-5 nm, which were primarily associated with nanoclusters as compared to other locations, with no observed faceting of the bubbles. Atom probe analysis confirmed helium partitioning to the Ta nanoclusters indicating the effective entrapment of these He atoms.
10.1016-j.scriptamat.2022.114559	6	grain; deformation; strain; strength; dislocation; cu-; tensile; size; ecap; grain size; sfe; ductility; hardening; high; stress	Deformation and subsequent annealing are often combined to optimize the overall mechanical properties of metallic materials. In this work, the strength-ductility trade-off between dynamic plastic deformation (DPD)-induced and annealed DPD structures in Cu and Cu-4.5Al alloy was compared. The strength ductility combination of the DPD Cu samples is inferior to that of the annealed DPD Cu samples, while the strength-ductility synergy of the DPD Cu-4.5Al samples is comparable to that of the annealed DPD Cu-4.5Al samples, for which the reasons were analyzed based on the tensile deformation mechanism of these samples. This work suggested that high performance metallic materials can be obtained by just one-step plastic deformation without subsequent annealing treatment, which would be an economic and effective way to improve the strength-ductility combination of face-centered-cubic metals and alloys with a low stacking fault energy.
10.1016-j.scriptamat.2022.115060	-1		The diffusion and segregation rates of immiscible alloying elements in Cu-based alloys with one (V) or five re-fractory metals (V, Nb, Mo, Ta and W) at 300 to 500 degrees C were investigated for understanding the kinetics of phase separation in multicomponent alloys. At a comparable grain size and a similar influence of grain boundary diffusion (more dominant at 300 degrees C), the summed rate constant of segregation of the five alloying elements was higher than that of the one element, attributable to the larger entropy change for vacancy formation and atom exchange. The rate constant and time exponent of segregation depended on the melting temperature of the alloying element (W > Ta > Mo > Nb > V), while the activation energy of diffusion, 5.1 to 12.3 kJ/mole (W < Mo < V < Nb < Ta), was inversely related to the delta mixing enthalpy (to Cu) or electronegativity.
10.1016-j.scriptamat.2023.115337	0	solidification; phase; magnetic; magnetic field; undercooling; field; liquid; separation; peritectic; immiscible; cu-; dendrite; phase separation; microstructure; primary	In this study, the selection process of low-energy grain boundaries of delta-Fe grains (>25 mu m) suspended in the liquid copper was studied based on the characteristics of Cu-Fe monotectic alloy which suggests that liquid Cu-rich phase and solid Fe grains can coexist over a wide temperature range. The distribution of grain boundaries was analyzed by EBSD, and it was found that sigma 3 and sigma 9 high angle grain boundaries with low energy were preferentially formed between delta-Fe grains at 1100 and 1150 degrees C. After heat treatment at 1200 degrees C, the delta-Fe grains agglomerated into a spherical shape with a structure, in which sigma 1 grain boundaries dominated. Thus, the selective attachment of low-energy interfaces between floating grains in the liquid phase was elucidated.
10.1016-j.scriptamat.2023.115478	-1		A double-peak precipitation hardening is observed in a simple one-step cold rolled Cu-0.75Fe-0.35Ti alloy upon aging at 500 degrees C, in which an early hardness peak (aging for 1 h) appears preceding the second one (aging for 6 h). Transmission electron microscopy observation reveals that profuse coherent precipitates keeping large lattice mismatch with matrix are formed in the 1 h-aged specimen, resulting in a strong coherency strengthening and accounting for the early hardness peak. With aging time increasing to 6 h, the precipitates evolve into incoherent Fe2Ti/FeTi precipitates and strengthen alloy through the Orowan bypass mechanism, responsible for the second hardness peak. Finally, the 1 h-aged CRA specimen shows a higher hardness (181.2 HV) than the 6 h-aged one (174.8 HV) while a comparative electrical conductivity (56.8%IACS) as the 6 h-aged one (59.8%IACS). Our findings provide the possibility to design high-performance Cu-Fe-Ti alloy with coherent precipitates through a rapid process.
10.1016-j.scriptamat.2023.115767	1	shape; memory; shape memory; damping; martensite; martensitic; damping capacity; transformation; capacity; strain; superelasticity; temperature; cu-al-mn; shape memory effect; effect	In this study, novel Cu-Mn-Ga-based (Cu-13Mn-6Ga-8Al-xMo, x = 0.5, 0.8, 1.0, wt. %) full superelasticity single crystals with great combination properties of low stress hysteresis, high critical stress, and full superelasticity were prepared for the first time. The results show that these single crystals consist of L21(1) austenite and A2(Mo) phase before and after annealing. The A2(Mo) phase increases with the increment of Mo content. Three single crystals with orientations close to [314], [415], and [236] all exhibit full superelasticity while applying large prestrains, even being up to 10 % in Cu-13Mn-6Ga-8Al-1.0Mo single crystal. More importantly, the superelasticity behaviors show high critical stress for inducing martensite (up to 723 MPa in Cu-13Mn-6Ga-8Al-1.0Mo single crystal) and low stress hysteresis (about 30 similar to 60 MPa). From the point of strength and functional characteristics, the Cu-13Mn-6Ga-8Al-xMo single crystals can be used as a new driving material.
10.1016-j.scriptamat.2023.115801	-1		Printing of thin -wall copper alloy components with high mechanical performance using selective laser melting remains challenging. Here, the introduction of the soft Cr nanoprecipitations via increasing the Cr to Nb atomic ratio based on commercial CuCrNb alloys can suppress the excessive formation of Cr2Nb Laves phase and enhance the deformability of CuCrNb microlattices. Small printing layer thickness contributed to the highdensity and small -size nanoprecipitations. Dual nanoprecipitations strategy enables us to successfully fabricate high -precision CuCrNb microlattices with the feature size down to 100 mu m and exceptional printability, high mechanical strength, and homogeneous deformability until densification strain. By tailoring the precipitation behavior of Cr phase at post -printing stage, CuCrNb microlattices can further enhance the mechanical performance. Our peak -aged Gyroid CuCrNb microlattice displays an ultrahigh specific energy absorption of 23 J/g without fracture at strain above 60 %, even surpassing that of some titanium and aluminum alloys lattice structures with low material densities.
10.1016-j.scriptamat.2023.115957	-1		Cu-Cr-based alloys are good candidates for thermo-electrical applications because of their excellent combination of mechanical, thermal, and electrical properties. However, tailoring their microstructure via traditional processes such as sintering and casting remains a challenging task. Herein, we introduce a strategy to fabricate multiscale Cu-25Cr composites. This is achieved through in-situ alloying from elemental powder blending in laser powder-bed fusion. The process is monitored layer-by-layer using synchrotron X-ray microtomography. We show that by changing the melt-pool size and its overlap, one can produce multiscale Cu-Cr composites with coarse (similar to 50 mu m) and fine Cr-spheroids (<500 nm) while controlling their spatial distribution. Coarse Cr particles are preferentially located at the melt pool boundaries while fine spherical Cr particles are distributed in the melt pool interior. Spatial variations in mechanical properties are revealed using nanoindentation mapping. This strategy opens new opportunities to optimize multiscale metal matrix composite through the manipulation of the scanning strategy.
10.1016-j.scriptamat.2024.116078	-1		Precipitate features including size, morphology, crystal structure, etc., are important parameters determining the performance of precipitate-strengthened alloys. Multiple Fe precipitates were identified in as-cast Cu alloys exhibiting the distinct features, which dramatically influence mechanical properties. However, a complete understanding of precipitation behaviors of Fe particles during casting, in terms of both microscopic kinetics and thermodynamics, remains experimentally challenging. Here, we report the combined implementation of transmission electron microscopy, Thermo-Calc calculations and First-principles calculations to map mechanisms and growth regimes of Fe precipitation in a Cu-Fe-Co system. Our analyses support the idea that to understand the microstructural evolution in the system, both thermodynamic and kinetic arguments must be taken into account. Then, using our multi-approach strategy, the complete picture of the formation and transformation of Fe precipitates is proposed. This work is vital to promote microstructural design for Cu-Fe(-Co) systems, and sheds new insights into understanding of intricate precipitation in alloys.
10.1016-j.scriptamat.2024.116092	1	shape; memory; shape memory; damping; martensite; martensitic; damping capacity; transformation; capacity; strain; superelasticity; temperature; cu-al-mn; shape memory effect; effect	We report the occurrence of stress -induced burst -type martensitic transformation in a (116) A oriented Cu 70.5 Al 17.5 Mn 12 single crystal. The burst -type transformation is observed in the reverse transformation of unloading from 250 K to 370 K in tension, showing strong coupling with plastic deformation in the temperature range between 310 K and 370 K. Such coupling greatly exacerbates the stress hysteresis and energy dissipation in association with the stress -induced transformation, resulting in a significant enhancement in the mechanical damping and degradation in the elastocaloric response. In particular, the merit index for damping exhibits a remarkably high value of 0.903 at 370 K, demonstrating the huge potential of coupled burst -type transformation and plastic deformation in manipulating damping properties. Moreover, it is evidenced that the microstructural evolution of burst -type transformation greatly deviates from that of the thermoelastic transformation.
10.1016-j.scriptamat.2024.116108	7	irradiation; shear; grain; ta; deformation; size; radiation; voids; nanocrystalline; simulations; similar; void; temperature; irradiated; boundaries	Grain boundary cracking is an important failure mode for many structural alloys, motivating study of the contributing factors in order to explore strategies to improve toughness. Previous studies suggest that certain boundaries exhibit this mode of cracking more frequently than others. To improve our understanding, the microstructural factors that influence crack nucleation under tensile loading were investigated using a combination of post mortem and in situ techniques for a Cu-15Ni-8Sn (wt%) alloy, which exhibits intergranular crack nucleation. These analyses revealed that the local mechanical behaviour contrast, caused by mismatch of Schmid factor and grain size between adjacent grains, is a significant factor and can even override grain boundary precipitation effects in some cases.
10.1016-j.scriptamat.2024.116387	-1		Cu-Ti alloys are key materials for use of next-generation high-strength elastic components to replace hazardous Cu-Be alloys, but the tensile strength and ductiltiy are difficult to cooperative control through the conventional aging treatment. In this study, we successfully induced an electric current pulse (ECP) to promote the nucleation and precipitation of metastable phases during the fabrication of Cu-Ti-Fe alloy. It is noteworthy that a large quantity of the nanoscale (3'- Cu4Ti phase rapidly precipitated under an extremely short electropulse duration (90 s). After further aging, higher density and finer (3'- Cu4Ti precipitates were detected in the matrix, which significantly hindered the occurrence of discontinuous precipitation (DP) behavior. Compared with traditional aging treatment, the tensile strength and elongation of alloy with ECP and aging increased by 103 MPa and 8%, respectively. These results provide guidance for the simultaneous strength-ductility enhancements of various metallic materials.
10.1016-j.scriptamat.2024.116466	-1		The Cu-Ta and Cu-Ta-Ti deposited alloys were successfully prepared by laser directed energy deposition. The occurrence of monotectic reaction in Cu-Ta alloy was evidenced under the condition of oxygen impurities and high cooling rate. The incorporation of Ti in Cu-Ta-Ti alloy promotes the transition from incoherent Cu/Ta interface to semi-coherent Cu/beta-Cu3Ti/Ta interface, facilitating the dislocations transmit across the interface. Additionally, the solid solution strengthening and the precipitation strengthening provide the Cu-Ta-Ti deposited alloy with a balance of excellent strength and ductility, where the Cu-Ta-Ti deposited alloy has an ultimate tensile strength of 744 f 8 MPa, a yield strength of 577 f 12 MPa, and a total elongation of 9.9 f 0.3 %.
10.1016-j.scriptamat.2025.116577	-1		In this study, the corrosion behavior of B30 copper-nickel alloy under two typical service conditions are comparatively investigated. Note that, the environmental conditions of crevice corrosion result in the transition of the corrosion film from a single-layer structure to a double-layer structure. Under full seawater exposure condition, a single-layer corrosion film is discovered, consisting of NiO/Ni(OH)2 and Cu2O/Cu2(OH)3Cl. However, under crevice corrosion, a distinct double-layer film structure emerges, with Ni(OH)2 predominating in the inner and a combination of Cu2O/Cu2(OH)3Cl and Ni(OH)2 in the outer, which can be attributed to the varying chloride ion tolerance levels of Cu2O and NiO.
10.1016-j.scriptamat.2025.116834	-1		After homogenization, hot forging and solid-solution treatment at 800 degrees C, the Cu-15Ni-9Sn alloy was cold-rolled to a 60 % thickness reduction and aged at 400 degrees C. After 1 h aging, spinodal decomposition produced the Sn and Ni enriched DO22 phase coherent with the matrix, while abundant nanotwins emerged in the vicinity of (Cu, Ni)3Sn precipitates in the recrystallized matrix. Compared to the as-rolled state, the alloy exhibited enhanced hardness (316 HV), ultimate tensile strength (1131 MPa), and electrical conductivity (9.7 % IACS). Extending aging to 4 h led to extensive (Cu, Ni)3Sn secondary phase formation and pronounced recrystallization, reducing strength to 855 MPa but increasing electrical conductivity to 11.7 % IACS and total elongation to 12.9 %. The synergistic interplay of spinodal decomposition, local recrystallization, precipitation and nano-twinning underpinned the superior mechanical and electrical properties of the 1 h aged Cu-15Ni-9Sn alloy.
10.1016-j.seppur.2019.116309	-1		A novel, clean and highly efficient vacuum separation technique for the commercial processing of copper dross is introduced in this article. The industrial treatment of 500 kg copper dross showed that under the conditions of 1523 K, 20-150 Pa and 5 h of heat preservation, three kinds of products can be obtained by vacuum distillation, namely, crude lead, lead sulfide, and a Cu-As-Sb alloy. During the process, waste gas and wastewater were not generated, and no reagents were added. The combined power consumption is less than 1500 kW.h/t. The process was perfectly coupled to the lead smelting system, and the product was returned to the main process without the need for additional equipment to process it separately.
10.1016-j.seppur.2020.117810	-1		Owing to the enhanced selective depolarization effect of the liquid Cu, Ti has been successfully collected from mixed oxide ores or slags by using advanced molten oxide electrolysis (MOE) configuring with a liquid Cu cathode. However, the products prepared via above process are Cu-Ti alloys. Additional process is needed for the separation of Ti from those alloys. To achieve this goal, here, we selected a simple electrochemical approach to separate Ti from the Cu-Ti alloys in molten salt. Compared to the pure Cu electrode, the Cu-Ti alloys with different Ti contents show more negative electro-oxidation potential, which, in principle, indicates that Ti could be electrochemically extracted from the Cu-Ti alloys. Furthermore, the results of constant current electrolysis show that the effective separation of Ti is affected by the anodic current density and the Ti content in the Cu-Ti alloys. Specifically, the anodic current density, enabling the effective separation of Ti, increases with the increase of the Ti content in the Cu-Ti alloys. We have fitted a relationship equation between the anodic current density and the Ti content, which will be helpful for guiding separation of Ti from the Cu-Ti alloys. These findings confirm the feasibility of the molten salt electrolysis for the separation of Ti, and also make the Ti extraction based on the advanced MOE a complete process.
10.1016-j.seppur.2024.128388	-1		Cu-Ag-Sb-Au alloy produced from lead anode slime reduction smelting through twice vacuum distillation is a high value-added precious metal resource. Currently, using pyrometallurgical process, the antimony and copper elements can be removed respectively by multistage oxidation refining, and then the precious metals are recycled by electrolytic refining. This process has a number of shortcomings such as high energy consumption, high pollution and low direct yield. In this study, a highly efficient new process for extracting precious metals from Cu-Ag-Sb-Au alloy by one-step bimetallic potential-controlled electrolysis is proposed. The electrolytic process of Cu-Ag-Sb alloy is studied by linear scanning voltammetry and electrochemical impedance spectroscopy, and the experimental verification is carried out under the guidance of Cu-Ag-Sb alloy experiments. The results show that gold and silver are enriched in the electrolytic anode slime, while copper and antimony are reduced and deposited on the cathode, which realizes the efficient separation of gold and silver from copper and antimony. The direct yield of precious metals and the anode treatment rate are as high as 99.97 % and 16.02 kg/day center dot A center dot m2, respectively, but the energy consumption is 453.90 kW center dot h/t only. This process strongly supports the treatment of Cu-Ag-Sb-Au alloy with low cost and high efficiency. At the same time, in combination with the vacuum distillation process, the oxidation refining is successfully removed from the lead and copper smelting system, thereby achieving efficient recovery and effective reuse of the precious metals.
10.1016-j.seppur.2024.128914	-1		The recovery of waste cupronickel not only can solve related environmental concerns but also facilitates the separation of valuable metals and reduces extra exploitation of natural ore resources. Here, high-efficiency and low-energy-consumption separation of copper (Cu) from waste 90/10 cupronickel (Ni-10 %) by electrolysis was clarified in choline chloride-ethylene glycol deep eutectic solvent (ChCl-EG DES). Electrochemistry showed that Cu can be dissolved feasibly as monovalent Cu(I), forming species such as [CuCl2]- and [CuCl3]2- , while Ni was restrained and entered into anode slime at controlled potential. Compared with Ni(II), Cu(I) can be easily reduced to Cu0, and elevating temperature can accelerate ions transportation and reduction rates. Potentiostatic electrolysis at bath voltage of 0.4 V found that highly pure Cu (99.9918 wt%) was obtained and the current efficiency reached up to 99.71 % with low specific energy consumption (169.18 kW & sdot;h & sdot;t- 1). A separation mechanism model of Cu from waste 90/10 cupronickel was proposed and the role of the DES was revealed, which possessed strong coordination ability and fast transport capacity for Cu(I), as well as significant potential difference between Cu and Ni. This strategy represents a promising and economical technique for recycling waste Cu-based alloy and extracting highly pure metals.
10.1016-j.sna.2016.12.008	-1		In this work, a two-way displacing Cu-Al-Ni/Polyimide shape memory alloy bi-morph without any post processing has been developed. The forward stroke was achieved with shape memory effect and the return stroke was due to the influence of flexible polyimide substrate. A custom made setup with electrical heating was developed to investigate the life cycle of the bi-morph at different voltages, ranging from 2V to 3 V. The austenite transformation temperatures of the bi-morph, was found to be A(s) = 215 degrees C and A(F) = 240 degrees C. Shape recovery ratio was calculated and the shape memory alloy deposited on 75 pm thick polyimide sheet exhibited better recoverability than 50 pm thick sheets. Further, maximum displacement of 19mm was observed from the edge of the bi-morph through plate heating. The effect of substrate thickness on the life cycle behavior of the bi-morph was investigated. The bi-morph showed minor signs of deformation when actuated at 0.5 Hz after 500 cycles. In addition the structural, morphological and thermal behavior of the SMA bi-morph has been investigated in detail. (C) 2016 The Author(s). Published by Elsevier B.V.
10.1016-j.solener.2022.09.047	2	corrosion; surface; film; electrochemical; films; spectroscopy; layer; current; solution; potential; resistance; composition; x-ray; ions; showed	In this study, an attempt has been made to acquire an in-depth understanding of the electroplating mechanism of Cu (In, Ga) Se2 quaternary thin films on FTO-glass substrates. A systematic approach starting with the study of unitary, binary, ternary, and finally quaternary deposition of the elements have been performed through cyclic voltammetry (CV). The salts used were CuCl2, H2SeO3, InCl3 and GaCl3 for each stage of deposition with varying combinations and proportions. CVs were first done for unitary Cu, Se, In and Ga elements, then binary combi-nations of Cu-In, Cu-Se, Cu-Ga, In-Se, In-Ga, and Se-Ga system, ternary baths of Cu-In-Se and Cu-In-Ga, In-Se-Ga and Cu-Se-Ga systems, and finally quaternary Cu-In-Ga-Se system. An optimum deposition potential of-0.65 V was chosen from the position of cathodic peaks for all the baths. A thorough structural and elemental analysis, defect densities, type of conductivity was carried out for the as-deposited films. Single step deposition of CIGS was found to be impossible, hence Ga was attempted to incorporate in the films through a two-stack approach . From the position and intensity of the cathodic peaks and the phase analysis, plausible mechanism has been proposed for the quaternary alloy.
10.1016-j.solmat.2006.07.001	-1		The c/a ratios of the nine ternary Cu-III VI2 compounds in the system Cu(Al,Ga,In)(S,Se,Te)(2) range from 1.939 for CuAlSe2 to 2.014 (CuInS2) at room temperature. The validity of. Vegard's law was presumed to determine the tetragonal deformation 1-c/(2a) for all pentanary mixed crystal compounds Cu-(III,III)-(VI-VI)(2). For six of these nine compounds it is possible to achieve zero tetragonal deformation by adjusting the correct cation and anion substitution. The calculations are performed for room temperature as well as for 500 degrees C, which is a typical temperature for the synthesis of thin films of these semiconductor compounds.
10.1016-j.solmat.2014.02.040	-1		This work reports on the syntheses of copper-gallium bimetallic nanoparticles by ultrasound-assisted chemical reduction method in alcohol solutions to prepare CuGaS2 thin films. Gallium metal (Ga) in the form of pellet was dispersed in tetraethylene glycol by ultrasonic treatment. The chemical reduction of copper sulfate (CuSO4) into copper metal by NaBH4 at the surface of the Ga droplets enabled the formation of Ga-Cu core-shell structure. The Ga droplets with submicrometer size were homogenously coated with similar to 40-nm Cu nanoparticles. The exothermic transition of the Ga-Cu core-shell nanocomposite materials Occurred at 485 degrees C, which corresponds to the crystalline phase formation of gamma-Cu9Ga4. Ga-Cu nanocomposites with a 1:1 ratio were deposited onto molybdenum substrate via electrophoretic deposition method as a precursor of CuGaS2, a p-type semiconductor. Mechanical pressing and sulfurization provided dense CuGaS2 thin films with good crystallinity and high phase purity.
10.1016-j.spmi.2021.106989	-1		In this study, high-performance ternary Cu-0.13 wt% Cr-0.04 wt% Zr (Cu-Cr-Zr) alloy films on flexible polyimide (PI) substrate were investigated for the metallization of flexible thin-film transistor. The optimized Cu-Cr-Zr film was endowed excellent electrical resistivity (21.7 mO mu m) and adhesion strength (5 B). The results showed that the sputtering rate increased with the increase of the sputtering power and pressure, and the adhesion strength tended to increase while the resistivity decreased with the rise of annealing temperature. X-ray diffraction (XRD) analysis showed that the copper grain size increased significantly as the rise of annealing temperature, which indicates the attenuation of the grain boundary scattering and accounts for the decrease of the resistivity. Compared with the glass substrate, lower resistance was achieved on PI substrate, which is related to the surface morphology. The smoothness and adhesion of the Cu-Cr-Zr film were improved more distinctly on the PI substrate can be attributed to more low interfacial energy sites of PI. Further mechanical bending test demonstrated that the robust Cu-Cr-Zr film has good stability and durability without significant deterioration after 50 k times bending.
10.1016-j.ssc.2009.06.004	-1		The low temperature specific heat and thermal conductivity of (Cu50Zr50)(94)Al-6 bulk metallic glass have been studied experimentally. A low temperature anomaly in the specific heat is observed in this alloy. It is also found that in addition to Debye oscillators, the localized vibration modes whose vibration density of state has a Gaussian distribution should be considered to explain the low temperature phonon specific heat anomaly. The phonon thermal conductivity dependence on temperature for the sample does not show apparent plateau characteristics as other glass materials do; however, the influence of the resonant scattering from the localized modes on the lattice thermal conductivity is prominent in the bulk metallic glass at low temperatures.
10.1016-j.ssc.2009.07.028	-1		Ground states of the immiscible Cu-Ta system are investigated by a hybrid approach of first-principles calculation and cluster expansion method. The obtained pairs, triplets, and tetrads cluster interactions show that the closer-packed cluster may not always contribute to stabilize structures. A CuTa(7) phase with a cage-like structure is predicted to be stable at ground state. The obtained spatial valence charge density shows that there exists a charge hollow within this cage-like structure, contributing to stabilize CuTa(7) phase. (C) 2009 Published by Elsevier Ltd
10.1016-j.ssc.2011.04.023	-1		A recent study of Cu55Hf45-xTix metallic glasses with 0 <= x <= 45 has revealed the formation of bulk metallic glasses (BMG) for 15 <= x <= 30. In the same composition range, the ratio of the glass transition temperature T-g. and the liquidus temperature T-l, showed a shallow maximum, consistent with the highest glass forming ability (GFA). Here, we present the results for some mechanical properties (Young's modulus and microhardness) and magnetic properties (magnetic susceptibility) of these alloys and compare their variation with x with those for T-g and the crystallization temperature T-x. All measured properties show monotonic variations with x with no particular features in the composition range for BMG formation, hence do not indicate BMG compositions. The applicability of different criteria for assessing GFA to studied alloy system is briefly discussed.
10.1016-j.ssc.2019.113736	-1		CuZr intermetallic has attracted wide attention because it exhibits a reversible martensitic transformation above 100 degrees C and could expand the application field of high temperature shape memory alloys. The relationship between the stacking fault energy (SFE) and conductivity of CuZr with different alloying elements (Al, Fe, Ni and Zn) is investigated by first-principles calculations. For < 001 > slipping direction, the values of unstable SFE for different alloys are predicted and conclude that adding Ni or Fe atom decreases SFE and improves the ductility. Moreover, the addition of Ni atom reduces the unstable SFE of CuZr even by 50%. Meanwhile, both CuZr-Ni and CuZr-Fe have larger conductivity than CuZr, CuZr-Zn and CuZr-Al. Consequently, the lower the unstable SFE of alloy, the better the conductivity. In this way, we can obtain CuZr-Ni or CuZr-Fe with good toughness and conductivity, which has potential applications to manufacture antennas and parabolic radars in aerospace.
10.1016-j.ssc.2020.113980	13	clusters; atomic; glass; atoms; composition; dynamics; metallic; icosahedral; glasses; simulations; molecular; cu-zr; molecular dynamics; metallic glasses; structural	The elastic properties of Cu-Al-Mn alloys with compositions along the Cu3Al -> Cu2AlMn line and bcc-based structures, are studied by means of first-principles calculations. From the calculated elastic constants, the Zener's anisotropy, sound velocities and Debye temperature are determined. The theoretical results compare well with the available experimental data. The influence of vibrations is introduced through the quasi-harmonic Debye model, and different properties are studied as functions of temperature and composition.
10.1016-j.ssc.2022.114814	-1		In this study, the structural, electronic, mechanical, and thermodynamic properties of Cu-Ti intermetallic compounds (Cu4Ti, Cu2Ti, Cu3Ti2, Cu4Ti3, CuTi, and CuTi2) were predicted using first-principles calculations. The formation enthalpy results show that all Cu-Ti intermetallic compounds are thermodynamically stable, and the thermodynamic stability decreased in the order CuTi > Cu4Ti3 > CuTi2 > Cu2Ti > Cu4Ti > Cu3Ti2. The elastic constants and polycrystalline moduli were obtained using stress-strain method and Voigt-Reuss-Hill approximation. The results show that all Cu-Ti intermetallic compounds are mechanically stable. The anisotropic elasticity increased in the order Cu4Ti < CuTi2 < CuTi < Cu2Ti < Cu4Ti3 < Cu3Ti2. The density of states verified that the Cu-Ti chemical bonds are formed by Cu-3d and Ti-3d hybridizations. In addition, the effects of high pressure (0-40 GPa) and temperature (0-1100 K) on the thermodynamic properties of these Cu-Ti intermetallic compounds were systematically studied based on the Quasi-harmonic Debye model. The isothermal bulk modulus and Debye temperature of these Cu-Ti intermetallic compounds increased with increasing pressure and decreasing temperature. The minimum thermal conductivity has the same order as the formation enthalpy.
10.1016-j.ssc.2023.115071	3	sma; shape; shape memory; memory; smas; superelastic; bars; damping; cu-al-mn; mechanical; bending; applications; numerical; sma bars; material	Freestanding thin films of Cu-Al-Ni shape memory alloys (SMAs) have attracted interests in recent years for the development of next generation micro-scaled sensors and actuators in MEMS. Thin films' capacity to recover stress-induced strain is critical to assess their potential for applications in these technologies. In this work, we report for the first time a quantitative study of this capacity in a freestanding Cu-Al-Ni thin film by Atomic Force Microscopy (AFM)-assisted nanoindentation. Stress-induced pseudoelastic (or superelastic) effects were suc-cessfully observed by this technique for relatively high strains up to a relative indentation depth of 30% con-cerning the film thickness. This effect highlights a clear shape memory effect, suggesting a sample's high mechanical performance for potential applications in the design of micro actuators for MEMS technologies. Results enable to set new perspectives of the use of this technique as an efficient methodology for future study of pseudoelasticity in micro/nanostructured SMAs.
10.1016-j.ssc.2024.115745	-1		In this research, the elastocaloric and magnetic properties of Cu70Al20.5Mn9.5-xCex (x = 0, 0.3, 0.6, 0.9) alloy are systematically studied. The resistance-temperature curve (R-T) revealed that the phase transition temperature range of the alloy is below room temperature (about 230-272 K) and increases as the Ce content increases. In addition, the thermomagnetic curve (M-T) and isothermal magnetization curve (M-H) suggested that the alloy exhibits weak magnetism. The X-ray diffraction pattern shows that the alloy is a single beta phase at room temperature. The stress-strain curve shows that with the increase of Ce content, the overall strain of the alloy tends to decrease, indicating that the addition of Ce will increase the compressive modulus of the alloy. The test of elastocaloric properties shows that the maximum adiabatic temperature change of the alloy initially decreases and then increases as the Ce content rises. When the Ce content is 0.3, it exhibits an adiabatic temperature change of 7.4 K under the stress unloading of 500 MPa. The temperature-time cycle test shows that Cu70Al20.5Mn9.2Ce0.3 has good elastocaloric cycle stability.
10.1016-j.ssc.2025.116060	-1		Conventional research tools are difficult to reveal the relationship between nanoscale microstructural changes and macroscopic properties of functional gradient materials (FGMs), and it is not clear how the gradient composition distribution regulates the mechanical properties of alloys. To this end, the present study employed a molecular dynamics (MD) approach to systematically investigate the tensile mechanical response of Cu-Al gradient alloys with different compositional distribution functions (power-law, exponential and S-type) and to analyse the effects of strain rate and temperature on the mechanical properties of Cu-Al functional gradient alloys with S-type distribution functions. It is found that P-FGM is suitable for symmetric strengthening design, E-FGM is used for fast gradient response design, and S-FGM is outstanding in suppressing stress concentration. The Sshaped distribution function with different functional parameters can effectively delay the accumulation of dislocations and improve the deformation uniformity. As the gradient parameter p increases, the ultimate tensile strength (UTS) of the material tends to decrease and the time of the peak of dislocations is delayed, which is a phenomenon mainly attributed to the fact that the smooth gradient effectively disperses the stress concentration and reduces the risk of local failure. In addition, an increase in temperature leads to a gradual transformation of the FCC structure of Cu-Al alloys into an amorphous structure, resulting in a significant decrease in strength . While the increase in the velocity of the deformation can enhance the strength, it also causes a loss of elongation. This highlights the relationship between the enhancement of the velocity of deformation and the reduction of plasticity. The present study utilised molecular dynamics simulations to reveal the correlation between the degree of layering and the properties of plasticity. This provides a foundation for the design of functional layered alloys.
10.1016-j.stam.2003.09.003	-1		The mechanical properties, glass-forming ability, supercooled liquid region and devitrification behaviour of the Cu-Zr-Ti-(Pd, Ag, Pt and Au) bulk glass formers were studied by using a mechanical testing machine, X-ray diffraction, transmission electron microscopy, differential scanning calorimetry and isothermal calorimetry. The bulk glassy alloys of diameter 2 mm were formed in the Cu55Zr30Ti10Pd5 and Cu55Zr30Ti10Ag5 alloys while Cu55Zr30Ti10Au5 bulk alloy showed mixed glassy and crystalline structure. No glassy phase was formed in the Cu55Zr30Ti10Pt5 bulk alloy whereas the glassy phase was formed in all of the ribbon samples prepared by rapid solidification. The studied alloys except for the Pt-bearing one have slightly increased compressive fracture or yield strength values compared to ternary Cu60Zr30Ti10 glassy alloy. At the same time Pd and Au addition significantly expand the supercooled liquid region of Cu-Zr-Ti glassy alloy and increase Young's modulus. A nanoicosahedral phase is primarily formed in the Cu55Zr30Ti10(Pd,Au)(5) glassy alloys in the initial stage of the devitrification process by nucleation and three-dimensional diffusion-controlled growth . Nearly the same quasilattice constant obtained in the Cu55Zr30Ti10(Pd,Au)(5) alloys illustrates the same type of the icosahedral phase in these alloys. However, no icosahedral phase was found in the Cu55Zr30Ti10(Ag,Pt)(5) alloys.
10.1016-j.surfcoat.2005.01.116	-1		Oxidation behavior of some Cu-Cr alloys (with 8.5-25.6 wt% Cr, in both stand-alone coupons and spray coatings on Cu-8Cr-4Nb) was studied by TGA and cyclic oxidation. Judging by the more stringent cyclic oxidation results, protection of the substrate Cu-8Cr-4Nb was effective for the whole 10-h duration of testing up to 750 degrees C only for coatings with 21% or higher Cr. Similar protection was exhibited by Cu-17Cr only up to 650 degrees C, and only for < 3 h at 750 degrees C. In all cases the Cr2O3 subscale nucleated discretely (and always under a non-adherent scale of Cu oxides), and passive protection did not start until the nuclei joined into a continuous barrier and parabolic oxidation kinetics set in. The only protection achieved before that stage of Cr2O3 coalescence was via sacrificial oxidation of the coating.
10.1016-j.surfcoat.2005.11.103	-1		Cu-Cr alloys are very interesting materials to study non-equilibrium phase transformations in binary systems containing immiscible metals as well as for practical applications as high-thermal conductivity and contact materials. We studied by high resolution secondary ion mass spectrometry and atomic force microscopy the chemical element distributions and surface morphology of Cu-Cr alloys irradiated with a low energy, high current electron beam. The irradiation conditions were: energy density 4 divided by 6 J cm(-2), pulse duration 2.8 divided by 3.6 mu s, number of shots 16. Cu-Cr alloys were prepared by powder metallurgy and contain 30 wt% Cr. While in samples irradiated at low energy density maps of surface elements reveal the presence of well separated micrometer-sized domains of Cr and Cu, after irradiation at high energy density sub-micron spots of coexisting Cu and Cr appear. This is a clear indication of CuCr compound formation, as also supported by local mass spectrometry. Irradiated samples have reduced roughness, especially in Cr domains, with respect to the pre-treated sample. However, microcracks and microcraters appear as beam energy density and number of shots increase, thus compromising the smoothening effect and the surface integrity.
10.1016-j.surfcoat.2006.07.208	2	corrosion; surface; film; electrochemical; films; spectroscopy; layer; current; solution; potential; resistance; composition; x-ray; ions; showed	A 20 mu m thick nanocrystalline (NC) Cu-70Zr film has been fabricated by direct current magnetron sputtering (DCMS). The NC film, with a mean grain size of 10-20 nm, has a composition identical to that of the conventional coarse-grained alloy. The electrochemical corrosion behavior of the NC film and the coarse-grained alloy in the hydrochloric acid solution was investigated by using potentiodynamic and potentiostatic polarization techniques. The results showed that the NC Cu-70Zr film had a lower corrosion rate and an increased localized corrosion resistance than that of the cast one. Compared with the microcrystalline Cu-70Zr alloy, the enhanced corrosion resistance was closely related to the homogeneous element distribution in the nanocrystalline Cu-70Zr film.
10.1016-j.surfcoat.2006.08.038	-1		An attempt to improve the load support for hard PVD coatings on soft Cu alloys has been made by using a medium phosphorous content electroless Ni-P coating prior to PVD deposition, envisaging the application of these coating/substrate systems in plastic injection moulding. Several PVD coatings, including TiN, CrN, CrAIN, multilayered CrAIN, WC-C, multilayered CrAIN/WC-C were deposited onto an Ampeoloy 940 Cu alloy in two conditions: 'standard' and electroless Ni-P plated. The effect of the electroless Ni-P coating on the coating/substrate performance was evaluated by pin-on-disc wear and impact tests. Ultra-microhardness and surface roughness measurements were also used to characterise the resulting coating/substrate systems. The electroless Ni-P coating reduced the wear rates of the PVD-coated Cu alloys and increased the impact wear resistance. Among the PVD coatings nialled, CrN, CrAIN and multilayered CrAIN coatings on electroless Ni-P provided the lowest wear rates.
10.1016-j.surfcoat.2006.09.314	16	wear; composite; composites; powders; milling; particles; powder; wt; sliding; friction; hardness; matrix; mechanical; surface; properties	In the present study, [Ni (4.5 nm)/Cu (t(Cu)=2, 4 and 8 nm)] multilayers were pulse electrodeposited on stainless steel (AISI SS 304) substrate from sulphate based single bath technique. X-ray diffraction (XRD) was used to investigate the structure and stress of the Ni/Cu multilayer. The results from XRD analysis indicated that the deposited multilayers had a preferred crystal orientation of [111] and presence of satellite reflection suggested the formation of superlattice. The stress level within the deposited multilayers was found to be sensitive to the sublayer thickness. Sliding wear behaviour of electrodeposited Ni/Cu multilayer films has been investigated against a tungsten carbide (WC) ball as the counter body and compared with that of the constituents, Cu and Ni coatings. The wear tests were carried out by using a reciprocating ball-on-flat geometry at translation frequencies of 5 and 10 Hz, slip amplitude of I mm and at five different loads of 3, 5, 7, 9 and 11N. Friction force was recorded on-line during the tests. At the end of the tests, the wear scars were examined by laser surface profilometry and scanning electron microscopy (SEM). Friction coefficient was found to be dependent on load and Cu layer thickness (t(Cu)) and the values for multilayers were border between Ni and Cu. Among multilayers, sample with minimum t(Cu) has shown the lowest friction coefficient and wear rate. With increasing t(Cu), the wear mechanism changes from pure abrasive wear at t(Cu) = 2 nm, to particle entrapment at t(Cu) = 4 nm to particle embedding at t(Cu) = 8 nm. Detailed investigation of the wear scar morphology as well as wear rate measurement revealed that at low loads, (HIE) ratio and residual stress governed the wear rate and the principle wear mode was abrasive cutting. At intermediate loads, the role of residual stress became insignificant while wear was governed by (HIE) ratio and plastic deformation. However, at higher loads, plastic deformation played the major role.
10.1016-j.surfcoat.2009.03.018	-1		Cu and Cu(Cr) alloy films were sputtered on Si substrates covered with thermally grown SiO2. Atomic force microscopy, transmission electron microscopy, nano-indentation and four-point probe method were used to characterize the microstructure and properties of films, respectively. It was found that a small amount of Cr refined the Cu grains and decreased the surface roughness of films. After annealing at 450 degrees C, in contrast to the Cu films with large equiaxed grains, the Cu(Cr) alloy films exhibited a bimodal grain size distribution with fine columnar grains. In addition, high-density twins and preferably oriented columnar grains were found in the Cu(Cr) alloy films. As a result, the hardness and Young's modulus of Cu(Cr) films were much higher than those of Cu films. The final resistivity of the annealed Cu(Cr) alloy films was 2.55 mu Omega cm which was close to that of the annealed Cu films.
10.1016-j.surfcoat.2009.09.080	2	corrosion; surface; film; electrochemical; films; spectroscopy; layer; current; solution; potential; resistance; composition; x-ray; ions; showed	Synergy effect of the surface modification of copper (Cu) by surfactant, cetyl trimethyl ammonium bromide (CTAB) and coupling agent, gamma-aminopropyltriethoxy silane (KH550), on the corrosion-resistant property of low infrared emissivity Cu/polyurethane (PU) coating formed on tinplate was evaluated. Infrared spectra revealed an obvious interaction between Cu and PU induced by the addition of KH550, which implied that KH550 can improve the chemical interfacial interaction while CATB only improved the physical interaction between Cu and PU. The corrosion behavior of Cu/PU coating has been investigated with potentiodynamic polarization. Results have shown that the interfacial interaction between Cu and PU was improved by the synergy effect of proper amount of KH550 and CTAB, benefiting to the dispersion of Cu and the low porosity of Cu/PU coating, which keeps the low infrared emissivity and increases the corrosion resistance of the Cu/PU coating formed on tinplate.
10.1016-j.surfcoat.2010.04.032	-1		Pure Cu film and Cu(Mg) films having 1-4.5 at% Mg were sputter-deposited on glass substrates, and annealed in vacuum at varying temperatures up to 400 degrees C. We investigated the effects of the Mg content and the annealing temperature on the resistivity and adhesion force of the Cu(Mg) film. We also discuss changes in surface morphologies such as agglomeration and hillock formation. The adhesion strength of the Cu film was greatly improved by adding Mg to the sputtering target. Cu(>= 2 at% Mg) films annealed at 350 degrees C showed critical loads over 300 mN, more than 10 times higher than the 5-26 mN of pure Cu films annealed at the same temperature. The incorporation of Mg also suppressed the agglomeration of the Cu film during annealing. The adhesion strength of Cu(2.7 at% Mg) film decreased with increasing annealing temperature due to the increase in the residual tensile stress in the Cu(Mg) film. Hillocks were observed in the Cu(Mg) film annealed at 400 degrees C. Cu(2-3 at% Mg) films annealed at 350 degrees C showed excellent adhesion strength to smooth-surfaced glass substrates without any glue layer, and had a relatively low resistivity of 3.5-41.0 mu Omega.
10.1016-j.surfcoat.2010.07.034	-1		In the present study, surfaces of copper substrates were modified with aluminum plasma using cathodic vacuum arc (CVA) physical vapor deposition based technique. Surface treatments were carried out as a function of bias voltage for various time intervals. The effect of long and short durations of ion bombardment on the resulting microstructural features of the treated surfaces were studied and discussed It was observed that surface alloying and diffusion processes were enhanced by the application of the ion bombardment and thick (10-15 mu m) modified zones were achieved in a relatively short processing time (15-20 min). In the experiment executed with long bombardment duration, the modified zone consisted of a mixture of martensitic beta(1)-AlCu3 phase and (Cu) solid solution, accompanied with a minor amount of gamma(1)-Al4Cu9 intermetallic phase, whereas, in the experiment involving short total bombardment duration, the modified surface predominantly consisted gamma(1)-Al4Cu9 intermetallic phase, accompanied with martensitic beta(1)-AlCu3 phase at the copper aluminum interface.
10.1016-j.surfcoat.2010.07.106	-1		The mechanical behavior of an electrodeposited nanocrystalline alloy is assessed with regards to the experimentally measured strain-rate sensitivity. Foils are characterized with grain sizes as small as 3 nm, a nano-scale regime that has previously gone without detailed experimental examination. It is found from micro-scratch measurements that hardness, hence strength, approaches ideal values as the grain size decreases to 7 nm. Below 7 nm, softening in strength and departure from Hall-Petch behavior is related to an increase in the activation volume for deformation as grain size decreases further.
10.1016-j.surfcoat.2010.12.032	16	wear; composite; composites; powders; milling; particles; powder; wt; sliding; friction; hardness; matrix; mechanical; surface; properties	Cu/Ni multilayer films with sublayer thickness (h) ranging from 10 to 1000 nm were prepared on ANSI 1045 steel by brush plating of periodically changing layers of Cu and Ni. The microstructure, composition, microhardness and sliding wear properties against standard SiC ball under unlubricated condition were examined. It was found that the brush plated multilayer films are highly dense and free from porosity. A decrease in h results in smaller grain size and lower coefficient of friction. Both microhardness and wear resistance reach the maximum value when h = 20 nm. Although found with lower hardness compared with brush plated Ni monolayer coating, multilayer films with h ranging from 20 to 80 nm showed improved wear resistance. The increase in the wear resistance was attributed to the combined effect of strengthening of the layer structure and the lubricating of Cu.
10.1016-j.surfcoat.2011.05.047	2	corrosion; surface; film; electrochemical; films; spectroscopy; layer; current; solution; potential; resistance; composition; x-ray; ions; showed	Cu1-xNix (0.43 <= x <= 1.0) films were electrodeposited from citrate-sulphate baths at different current densities onto Cu/Ti/Si (100) substrates with the addition of saccharine as a grain-refining agent. The Cu-Ni alloy films produced from saccharine-free baths were fine-grained (crystallite size of similar to 400 nm). The addition of saccharine to the electrolytic solution induced a dramatic decrease in crystal size (down to similar to 27 nm) along with a reduction in surface roughness. Although the effect of saccharine on pure Ni films was less obvious, significant changes were observed due to the presence of saccharine in the bath during the alloying of Cu with Ni. Compared to fine-grained Cu-Ni films, the nanocrystalline films exhibited lower microstrains and a larger amount of stacking faults as observed by X-ray diffraction. These features enhance the mechanical properties of the Cu-Ni alloys, making the nanocrystalline Cu-Ni films superior to both the corresponding fine-grained films and pure Ni films. In particular, hardness in fine-grained films varied from 4.2 (x=0.43) to 5.4 GPa (x=0.86), whereas hardness varied between 6.7 and 8.2 GPa for nanocrystalline films of similar composition. In addition, wear resistance and elastic recovery were enhanced. Nanostructuring did not significantly affect corrosion resistance of Cu-Ni alloys in chloride media. Although the corrosion potential shifted slightly towards more negative values, the corrosion current density decreased, thereby making the electrodeposition nanostructuring process an effective tool to improve the overall properties of the Cu-Ni system.
10.1016-j.surfcoat.2011.08.032	-1		Copper composite coating with graphite (C-g) and/or silicon carbide (SiC) particles were deposited by electroless plating. The surface morphology of the coatings that were analysed using scanning electron microscopy (SEM) showed that Cu particles were uniformly distributed. The obtained coating thickness was approximately +/- 5 mu m. X-ray diffraction (XRD) and differential scanning calorimetry (DSC) techniques were used to characterise the structure and to study the phase transition of the coatings, respectively. Phases such as Cu, Cu2O, Cu3P, Cu3Si, SiC and C-g were observed from X-ray diffraction patterns and the presence of Cu2O, Cu3P and Cu3Si was confirmed by differential scanning calorimetry (DSC) studies. The results demonstrated that SiC and C-g particles have little influence on the phase transition of the coating. The hardness and wear resistance of Cu-P composite coatings were improved with the incorporation of SiC particles. The friction coefficient of Cu-P composite coatings decreased with the incorporation of C-g particles. Atomic force microscopy (AFM) results of coatings showed that the roughness of the coatings increased with the incorporation of SiC to the Cu-P coatings and decreased with the incorporation of C-g. Cu-P-C-g-SiC composite coatings showed a moderate roughness, hardness between Cu-P-SiC and Cu-P-C-g coatings, had low friction and good anti-wear properties. The anti corrosion resistance of the electroless Cu-P composite coatings on carbon steel were studied in 3.5% NaCl and 1 M HCl solutions by the potentiodynamic polarisation technique. The study revealed that the corrosion resistance increased with the incorporation of SiC particles in the Cu-P and Cu-P-C-g matrix but reduced with the incorporation of graphite.
10.1016-j.surfcoat.2012.08.047	2	corrosion; surface; film; electrochemical; films; spectroscopy; layer; current; solution; potential; resistance; composition; x-ray; ions; showed	A comparative study was carried out on the deposition mechanism. microstructure, and corrosion resistance of Cu films electrodeposited from the base electrolyte of CuCl2 center dot 2H(2)O in a choline chloride-ethylene glycol eutectic solvent with absence and presence of the additive of ethylene diamine (EDA). The base electrolyte is unstable and produces rough Cu films with columnar grains. Upon the introduction of EDA, the modified electrolyte becomes stable and the nucleation of Cu deposits is strongly inhibited, thus producing a smooth and compact surface with finer grains. Uniform corrosion and decreased corrosion current density are recognized in the fine grained Cu films. (C) 2012 Elsevier B.V. All rights reserved,
10.1016-j.surfcoat.2012.10.017	-1		The structural changes and electrical properties of copper hafnium (Cu(Hf)) thin films have been investigated. After annealing the Cu(Hf) film in an oxygen atmosphere, the surface of the film was capped with a self-formed HfO2 layer to diminish copper oxidation and reduce the electrical resistivity of the films. The outward diffusion of Hf atoms from the Cu(Hf) matrix was confirmed by X-ray diffraction, four-point probe measurements, Auger electron spectroscopy, and transmission electron microscopy. A Cu film with high Hf content exhibited superior passivation characteristics when the film was annealed in an oxygen atmosphere, but it also had high resistivity because of the high Hf content. The leakage current of the Cu(Hf) film was also markedly improved, revealing that Hf is a promising doping element for Cu interconnects and thin-film transistors.
10.1016-j.surfcoat.2013.06.062	-1		This work focuses on the properties of a Cu-3 wt% Ag-0.5 wt% Zr alloy deposited by a Cold Spray process. Helium was used as the carrier gas and main gas to obtain a high deposition efficiency, low porosity and high mechanical properties. The effect of deposition parameters and heat treating on the microstructure and mechanical properties was explored. An ultimate tensile strength higher than 650 MPa, a yield strength of about 600 MPa and a Vickers micro hardness HV0.2 higher than 220 were obtained, values which compare quite favorably with those corresponding to a classically forged material. The deposits microstructure and more particularly the plastic deformation of particles upon impact were observed by optical and electronical microscopy. The residual stress level was also investigated as a function of heat treating.
10.1016-j.surfcoat.2013.10.020	2	corrosion; surface; film; electrochemical; films; spectroscopy; layer; current; solution; potential; resistance; composition; x-ray; ions; showed	Currently Cu-Sn coatings are widely used in numerous commercial productions in replacement of Ni layers especially for decorative arts. In recent decades, researchers are exploring more environment-friendly baths to deposit Cu-Sn coatings to substitute CN- electrolyte which has been widely used as conventional electroplating baths for industrial applications. This paper investigated Cu-Sn deposition from a methanesulfonic acid based bath studying the optimization of deposition parameters. Film composition was varied by changing current density, which leads to a difference in color and final properties. Usually lifetime of tin containing baths is limited because the composition of deposited films has poor stability. In this work the effect of deposition parameters and anode materials on bath and deposits stability is evaluated. In particular, the application of pulse current was considered to improve the quality of coatings at fixed duty cycle while deposition frequency was varied. The coatings deposited under different conditions were compared in term of microstructure and corrosion behavior.
10.1016-j.surfcoat.2014.08.015	-1		A plasma-nitriding procedure was applied to enhance the surface hardness and wear toughness of practical age-hardenable Cu-4 mol%Ti alloy. Plasma nitriding at 1073 K and 1173 K leads to the formation of TiN surface layers with thicknesses of 300 nm and 350 nm, respectively, above Cu3Ti3O layers with thicknesses of approximately 700 nm and 2200 nm. In other words, the thicknesses of the surface compound layers increase with plasma nitriding temperature, which also increases the surface hardening. In particular, the hard TiN and Cu3Ti3O on the surface contribute to hardening of the surface to Vickers hardness of around 10 GPa, which is much greater than the hardness of the substrate alloy of approximately 1.6 GPa. The surface layers also modified the wear resistance significantly. Thus, an optimized plasma-nitriding procedure is a promising surface modification technique for age-hardenable Cu-Ti dilute alloys.
10.1016-j.surfcoat.2014.12.002	-1		A new method was explored for inner surface alloying on pores of lotus-type porous copper. Zinc was deposited on the inner surface of pores by electroless plating with thorough supersonic vibration. Then, the Cu substrate together with Zn coatings was transformed into a brass layer by annealing treatment. From images filmed by a digital single lens reflex camera and a field emission scanning electron microscopy, it can be observed that the appearance and microstructure of lotus-type porous copper surface and pore walls were changed after the sequential treatments. The statistical thickness of the alloy layer at the distance of 0.5 mm from pore openings increased with the electroless plating time increase, attaining a maximum of about 1.7 mu m when the time exceeded 1.5 h . The alloy layer thickness at the sample height of 25 mm along the pore axial direction was determined as about 1.5 mu m by the nano-indentation technique. Uniform coating and alloy layer can be achieved on the inner surface of 5 mm-long pores. The influence of annealing temperatures on phase compositions was studied by X-ray diffraction.
10.1016-j.surfcoat.2014.12.019	2	corrosion; surface; film; electrochemical; films; spectroscopy; layer; current; solution; potential; resistance; composition; x-ray; ions; showed	The voltammetric profile of Cu-Sn-Zn ternary alloys electrodeposition onto AISI 1010 steel from an acid bath containing disodium ethylenediaminetetraacetate (EDTA) showed four different cathodic regions, depending on bath composition, which were associated with the reduction of [CuY](2-), [SnY](2-) and [ZnY](2-) complexes through of the analysis of the voltammetric curves together with the energy-dispersive X-ray spectroscopy results. However, Cu-Sn-Zn co-deposition occurred only at electrodeposition potentials (E-d) more negative than 1.26 V, depending on bath composition, indicating that a transition E-d exists wherein a transition from Cu-Sn binary alloy to Cu-Sn-Zn ternary alloy occurred. Analysis of the photomicrographs showed that Cu-Sn-Zn electrodeposits showed dense and uniform morphologies depending on E-d and bath composition. Also, adhesion tests showed that the Cu-Sn-Zn electrodeposits obtained at E-d-1.70 V, with q(d) of 3.0 C cm(-2), from baths containing 0.20 M CuSO4 + 0.050 M SnCl2 + 0.050 M ZnSO4 and 0.10 M CuSO4 + 0.10 M SnCl2 + 0.10 M ZnSO4 presented good adherence. X-ray diffraction of Cu-Sn-Zn electrodeposits obtained at E-d-1.70 V, with qd of 3.0 C cm(-2), showed a mixture of Zn, Sn, CuO, ZnO, SnO, eta-Cu6Sn5, Cu20Sn6 and CuZn phases, depending on bath composition, indicating the formation of Cu-Sn-Zn ternary alloy.
10.1016-j.surfcoat.2015.04.003	2	corrosion; surface; film; electrochemical; films; spectroscopy; layer; current; solution; potential; resistance; composition; x-ray; ions; showed	A copper sulfide (digenite phase, Cu9S5) film composed of hierarchical microprotrusions was fabricated for corrosion protection of the underlying Cu substrate. The copper sulfide microprotrusions follow a heterogeneous nucleation, growth and aggregation mechanism. After hydrophobization with stearic acid, the film exhibits a water contact angle of 163 and a sliding angle of similar to 2 degrees, and shows enhanced corrosion resistance. The mechanism of corrosion protection is clarified according to the proposed equivalent circuits, which show that the superhydrophobic film behaves as an effective barrier and largely separates the Cu substrate from the corrosive solution. The film exhibits good chemical stability against acidic or basic solutions due to the chemical inertness of copper sulfide. It shows good adhesion to the substrate and maintains its hydrophobic property after abrasion test. (C) 2015 Elsevier B.V. All tights reserved.
10.1016-j.surfcoat.2015.08.061	-1		ZrCuAlNiTi metal glass (MG) powders were prepared by inert gas-atomization with a mean pal-tide size of 40 pm. Copper based composite with a 5% weight fraction of metallic glass powder were manufactured using cold spraying. Microhardness, tensile test (NOL ring samples) and tribology test were employed to characterize the corresponding deposits. The influence of the metallic glass particles (MG) addition and post heat treatment on the microstructure and mechanical properties of the composite was studied with a focus on the interaction between the matrix and the reinforcing particles. The composite exhibits higher tensile strength (about 366 MPa) than pure copper in the as sprayed condition and also better elongation which increases from 3.0% to 6.6% following the addition of MG. A lower wear rate (0.62 x 10(-5) mm(3)/(N x m)) of the composite indicates that the MG particles allow improving the wear resistance.
10.1016-j.surfcoat.2015.11.003	-1		Plasma carburization was performed on specimens of a commercially used age-hardenable Cu-Ti alloy, in order to improve its surface hardness and wear toughness. Specimens of a Cu-4 mol% Ti alloy were carburized in a methane gas glow discharge plasma at temperatures of 1073 K and 1123 K for 6 h . The plasma-carburization treatment resulted in the formation of two layers of crystalline compounds on the surfaces of the Cu-4 mol% Ti alloy specimens: (i) a TiC top layer containing 11 at% oxygen and (ii) a Cu3Ti3O sublayer. The thicknesses of the TiC and Cu3Ti3O layers were approximately 100 nm and 900 nm, respectively, in the case of the specimen plasma-carburized at 1073 K. This led to significant improvements in the surface hardness and wear toughness of the specimen. It was interesting to note that the presence of a carbon-friendly alloying element (Ti) at a concentration of only 4 mol% resulted in the formation of a hard TiC layer, leading to the surface hardening of the Cu-based alloy. Furthermore, plasma carburization at a higher temperature of 1123 K resulted in the formation of thicker layers of hard TiC and Cu3Ti3O, causing a greater degree of surface hardening. Thus, it was demonstrated that plasma carburization is highly suitable for the surface modification of age-hardenable Cu-Ti dilute alloys.
10.1016-j.surfcoat.2016.06.024	-1		Co-sputtering from confocal sources is a widespread technique for the production of thin film alloys. In this process the substrate is rotated to ensure that the films are homogeneous in thickness and composition. Even though the choice of substrate rotation speed is a critical parameter in such depositions, its influence on the resulting film's homogeneity has not been studied systematically. This work addresses the question from a different angle: the formation of multilayers as a function of substrate rotation speed is investigated. A very simple and widely applicable model is developed to predict the period and the composition of the multilayers as a function of the radial position and the substrate rotation speed. The model is benchmarked with characterization results of an immiscible Cu-56 at% Ta metastable alloy, which is co-sputtered with varying substrate rotation speed. It is shown that the model can predict the period of the composition modulations very accurately, and its predictive power with respect to the amplitude of the composition modulation is only limited by intermixing due to Cu surface segregation during the deposition process. Multilayers with a minimum period of 1 nm could be prepared in the Cu-Ta system using this method.
10.1016-j.surfcoat.2017.04.049	-1		In order to apply solid solution Cu(Ge) film to a barrierless structure for Cu interconnection, a binary Cu(Ge) solid solution film was prepared on the single-crystal Si(100) substrate by magnetron sputtering, followed by vacuum annealing. It was found that the individual addition of Ge led to serious interfacial diffusion promoting Cu-Si reaction. Therefore, Fe (or Sn) was chosen as the third element to prepare Cu(Ge-Fe(or Sn)) ternary films. The strong interactions from the negative mixing enthalpy between Ge-Fe(or Sn) stabilizes Ge in the Cu lattice, improving the thermal stability of the film. After 400 degrees C/1 h annealing, the Cu99.19Ge0.73Fe0.08 and CU99.22Ge0.69Fe0.09 films with the largest lattice distortion remained stable with the resistivity as low as 2.54-2.80 mu Omega cm. For Cu(Ge-Sn) films, the Cu-Si reaction did not occur in the Cu99.01Ge0.90Sn0.09 films with the largest lattice distortion, and the resistivity was maintained at 2.51 mu Omega cm. The results proved that strong interaction elements Fe and Sn could prevent the diffusion of Ge and enhance the stability of Cu alloy films. The addition of small atomic radius element Fe, which has large diffusion activation energy and small diffusion coefficient in Cu, could inhibit diffusion for a wide range of composition.
10.1016-j.surfcoat.2017.05.029	16	wear; composite; composites; powders; milling; particles; powder; wt; sliding; friction; hardness; matrix; mechanical; surface; properties	Aluminum nitride (AlN) is a potential ceramic particle to improve the wear resistance of copper surface. The present work is focused on synthesizing Cu/AlN (0,6,12,18 volt) copper matrix composites (CMCs) on pure copper substrates through friction stir processing (FSP). AlN particles were compacted into grooves machined on the surface of the copper plates. FSP was carried out under a set of fixed experimental conditions. The microstructural features were analyzed using optical, scanning and transmission electron microscopy. The wear behavior was assessed using a pin-on-disc apparatus. AlN particles were distributed homogenously in the surface composite. There were no clusters and segregation of AlN particles. The distribution was almost constant across the depth of the surface composite. There was a good interfacial bonding between AlN particles and the copper matrix. There was no major change in shape and size of AlN particles subsequent to FSP. Fine equiaxed grain structure was observed in the composite induced by dynamic recrystallization and pinning effect of AlN particles. The dry sliding wear behavior of the composite surface was reported in detail.
10.1016-j.surfcoat.2017.06.063	-1		Laser cladding is an effective way to improve wear resistance of copper alloys, however, low deposition rate is a main drawback that retards its industrial applications. Metal silicide based composite coatings were prepared on pure copper substrate by laser -induction hybrid cladding with a 5 kW fiber laser efficiently, and the powder feeding rate can reach 88.7 g/min. Cr13Ni5Si2, Cr3Ni5Si2 and Cu -based solid solution (Cuss) are main constituent phases in the composite coatings. Moreover, hardness of the different phases was evaluated bynanoindentation. Results indicated that the Cr13Ni5Si2 with high hardness (15.8 GPa) is acted as strengthen phase in the composite coatings, while the Cr3Ni5Si2/Cuss with good toughness are acted as toughness phases. Synergistic effect of the strengthen phase and the toughness phases endows the composite coating with excellent wear resistance, and dry slide wear resistance of the composite coating at 600 degrees C is 21.9 times higher than that of the stainless steel 1Crl 8Ni9Ti. 2017 Elsevier B.V. All rights reserved.
10.1016-j.surfcoat.2018.01.016	17	wear; composites; coating; friction; composite; coatings; surface; tribological; properties; wear resistance; resistance; powder; sliding; matrix; wear rate	Cu-15Ni-8Sn coatings were prepared using atmospheric plasma spraying. The influences of arc current and aging treatment on the microstructure, mechanical and tribological properties were investigated. The coating microstructure, the wear track and the wear debris were observed and analyzed. The melting state of the particles is improved by increasing of arc current. The hardness of the aged coatings is higher than the as-sprayed coatings. The wear resistance of the aged coatings is 3-4 times higher than the as-sprayed coatings. The continuous smooth tribolayer formed on the wear tracks contributes to the low wear rate of aged coatings. The dominant wear mechanism of the coatings is delamination coupled with spalling under dry sliding condition. This work provides an effective method for producing spinodal alloy coatings with enhanced mechanical and tribological properties.
10.1016-j.surfcoat.2018.04.007	2	corrosion; surface; film; electrochemical; films; spectroscopy; layer; current; solution; potential; resistance; composition; x-ray; ions; showed	Transfer and growth of pathogenic microorganisms must be prevented in many areas such as the clinical sector. One element of transfer is the adhesion of pathogens to different surfaces and the purpose of the present study was to develop and investigate the antibacterial efficacy of stainless steel electroplated with a copper-silver alloy with the aim of developing antibacterial surfaces for the medical and health care sector. The microstructural characterization showed a porous microstructure of electroplated copper-silver coating and a homogeneous alloy with presence of interstitial silver. The copper-silver alloy coating showed active corrosion behavior in chloride containing environments. ICP-MS measurements revealed a selective and localized dissolution of copper ions in wet conditions due to its galvanic coupling with silver. No live bacteria adhered to the copper-silver surfaces when exposed to suspensions of S. aureus and E. coil at a level of 10(8) CFU/ml whereas 10(4) CFU/cm(2) adhered after 24 h on the stainless steel controls. In addition, the Cu-Ag alloy caused a significant reduction of bacteria in the suspensions. The coating was superior in its antibacterial activity as compared to pure copper and silver electroplated surfaces. Therefore, the results showed that the electroplated copper-silver coating represents an effective and potentially economically feasible way of limiting surface spreading of pathogens.
10.1016-j.surfcoat.2018.04.019	2	corrosion; surface; film; electrochemical; films; spectroscopy; layer; current; solution; potential; resistance; composition; x-ray; ions; showed	The paper focuses on a novel method for enhancing the biofouling resistance of cupronickel (90-10 Cu-Ni) alloy by surface modification involving sand blasting, pickling and coating with silane. After optimizing the experimental parameters for polishing, pickling and sandblasting in order to develop a hydrophobic surface, the surface morphology and the wetting properties of the modified surface were characterized using scanning electron microscopy (SEM), atomic force microscopy (AFM), confocal laser scanning microscopy (CLSM) and contact angle meter. The enhancement in resistance to bacterial adhesion was demonstrated by adhesion studies on Pseudomonas sp., the major biofilm former in marine environment. The silane based coating on the sand blasted surface of cupronickel alloy brought about two order reduction of bacterial attachment as compared to the control sample.
10.1016-j.surfcoat.2018.04.046	-1		Cu-Sn-Zn coatings have been widely used in industry for their unique properties, such as good conductivity, high corrosion resistance and excellent solderability. To further improve the mechanical performance of Cu-Sn-Zn coatings, powder-enhanced method was applied and Cu-Sn-Zn-TiO2 nano-composite coatings with different TiO2 concentration were fabricated. The microstructure of Cu-Sn-Zn-TiO2 nano-composite coatings were investigated by X-ray diffraction (XRD) and Scanning Electron Microscopy (SEM). The mechanical properties of coatings including microhardness and wear resistance were studied. The results indicate that the incorporation of TiO2 nanoparticle can significantly influence the properties of Cu-Sn-Zn coatings. The microhardness of Cu-Sn-Zn coating was increased to 383 HV from 330 HV with 1 g/L TiO2 addition. Also, the corrosion resistance of coating was enhanced. The effects of TiO2 nanoparticle concentration on the microstructure, mechanical properties and corrosion resistance of Cu-Sn-Zn-TiO2 nano-composite coatings were discussed.
10.1016-j.surfcoat.2018.07.012	-1		Two Cu-9Ni-6Sn coatings with and without Sn-rich precipitates were obtained by laser-cladding. For two cross-section of coatings, the corrosion resistance can be graded in the order as equiaxed dendrite zone > dendrite zone > planar zone > Fe substrate due to the difference in composition and microstructure of the four zones. The coating with Sn-rich precipitates suffered severe localized corrosion, whereas general corrosion morphology was presented for the coating without Sn-rich precipitates. Clearly, a single-phase coating with large equiaxed dendrite zone should be developed by optimizing laser parameters for prolong the service life.
10.1016-j.surfcoat.2018.10.069	-1		It has been hypothesized that introduction of proper solute atoms, which preferentially segregates to grain boundaries, can stabilize the nanoscale grain size at elevated temperatures. To explore this possibility, we synthesized pure Cu and Cu-3 at. % W nanocrystalline films using magnetron sputtering. Scanning electron microscopy and x-ray diffraction showed that while grains in pure Cu coarsen rapidly when annealed at 673 K, Cu-3% W maintains a stable microstructure when annealed at the same temperature, achieving grain size of 37 nm after 120 min annealing. Nanoindentation measurements gave results consistent with the grain size evolution: upon annealing at 673 K, the hardness of the pure Cu film decreases to 40% of its initial value after 20 min, while the Cu-3% W film retains more than 90% of its initial hardness even after 120 min. Atom probe analysis shows W segregation in the Cu-3% W film. Results of this study indicate that solute segregation can be used as a method to fabricate nanocrystalline materials that are stable against grain coarsening at elevated temperatures.
10.1016-j.surfcoat.2018.12.035	-1		In this study, the precipitate strengthened Cu-Ni-Si alloy was micro-shot peened by ceramic balls with a diameter of 40 mu m. The fatigue tests using the peened specimens were conducted in air and in salt atmosphere respectively. The results show that a fine and hardening layer is formed on the surface of peened specimen and the compressive residual stress is introduced. There is no fatigue limit for specimens in both test conditions. The S-N curve of specimens in salt atmosphere shows a continuous decrease with the increasing number of loading cycles, while that in air shows a step-wise shape. Compared with the un-peened specimens, the fatigue strengths of specimens at 10(7) cycles are increased by 47% and 67% in air and in salt atmosphere respectively. The peened specimens in air condition failed from subsurface zone in high cycle fatigue region, while all the other specimens failed from surface. The micro-shot peening can improve the surface property and delay the crack initiation and propagation, so as to enhance the fatigue strength greatly.
10.1016-j.surfcoat.2019.01.029	2	corrosion; surface; film; electrochemical; films; spectroscopy; layer; current; solution; potential; resistance; composition; x-ray; ions; showed	This work describes the morphology, corrosion resistance, and antibacterial performance of copper coating deposited onto carbon steel by cold gas spray (CGS). Cross-sectional images of the coating showed a dense microstructure, with porosity lower than 1%. XRD analysis revealed no oxides or phases different to pure copper. The results of electrochemical tests demonstrated the efficient barrier properties and the compact microstructure of the coating, which protected the substrate against corrosion in chloride solution for > 1000 h . The copper coating was effective as an antimicrobial agent for inhibiting the growth of Staphylococcus aureus, with bacterial growth being completely inhibited after 10 min of direct contact between the bacteria and the coating surface.
10.1016-j.surfcoat.2019.02.039	-1		Cu-10Ni alloy with a gradient nano-structured surface layer was synthesized by ultrasonic surface rolling process (USRP). The microstructure and mechanical properties of the nanosurface layer were characterized by Xray diffractometry (XRD), microhardness testing, scanning electron microscope (SEM) and transmission electron microscope (TEM). The corrosion behavior of the USRPed and coarse-grained (CG) Cu-10Ni alloy in a 3.5 wt% NaCl solution was investigated. The results showed that the topmost surface possessed an average grain size of 70 nm, and the corresponding surface hardness increased by 80% after USRP treatment. Additionally, the electrochemical test results showed that the USRPed Cu-10Ni alloy exhibits enhanced corrosion resistance relative to that of the CG sample in a 3.5 wt% NaCl solution. The higher corrosion resistance of the nanograined Cu-10Ni alloy was attributed to the nanograined surface promoting the formation of a passivation film on the surface during the corrosion process, which can effectively prevent further corrosion. This study demonstrates that the hardness properties and corrosion resistance of Cu-10Ni alloys can be improved simultaneously by means of surface nanocrystallization.
10.1016-j.surfcoat.2019.125316	-1		Cu-Ni-Fe-Mo-xCr type alloy coatings with different Cr content were produced on a medium carbon steel substrate by laser cladding in this investigation. The effect of Cr content on macro-quality, microstructure, phase structure and high temperature oxidation resistance of the coatings was revealed by macro photography, optical microscopy (OM), environmental scanning electron microscopy (ESEM) incorporating with EDX microanalysis, X-ray diffraction (XRD) analysis, respectively. Results showed that, the coatings with Cr content ranging from 0 to and 5 wt% are smooth and crack free while the coatings with Cr content ranging from 7.5 to and 10 wt% are smooth but cracked. The volume content of second phase (Fe,Ni,Si,Cr)(2) Mo and the high temperature oxidation resistance of the coatings are both increased with an increase in Cr content.
10.1016-j.surfcoat.2020.125455	-1		To study the influence of the geometric structure on the surface wettability of metal materials, sub-millimetre sinusoidal and rectangular shapes were prepared on the surface of a Cu alloy by wire electrical discharge machining (WEDM). It was found that micro- and nano-scale craters and asperities are formed on the surface of the Cu alloy due to the electric spark discharge process, which leads to a multi-scale hierarchical surfaces formation on the Cu alloys. In addition, the thermal action of the spark discharge causes rapid remelting on the surface of the Cu alloy to form a recast layer with an elevated hardness but does not significantly affect the chemical composition. The formation of multi-scale sub-millimetre structures improves the hydrophobicity of the surface of the Cu alloy, wherein the maximum contact angles of the sinusoidal structure and the rectangular structure can reach 152.1 degrees and 149.1 degrees, respectively. Periodic changes in the structure effect on the wettability of the material surface. For the sinusoidal structures, the static contact angle of the droplets is not sensitive to periodic changes when the period is small, but when the period increases to a certain value, the wetting state of the droplets changes and the contact angle decreases significantly. For the rectangular structure, the contact angle of the droplets first increases and then decreases with increasing period. In contrast, the sinusoidal structures exhibit a better hydrophobicity than that of the rectangular structures due to changes in the curvature of the solid-liquid contact surface. The servo voltage during WEDM can significantly affect the shape and size of the micron-scale structures on the surface, resulting in the static contact angle of the droplet increasing first and then decreasing with an increase in the servo voltage.
10.1016-j.surfcoat.2020.125937	17	wear; composites; coating; friction; composite; coatings; surface; tribological; properties; wear resistance; resistance; powder; sliding; matrix; wear rate	The ZrB2-ZrC reinforced Cu matrix composite coating was prepared on a copper substrate by laser cladding and a self-propagating high-temperature synthesis (SHS) reaction. The zirconium ceramics were in-situ synthesized according to the designed SHS reaction within the coatings. The macromorphology, microstructure, phase composition, the interface of the zirconium ceramic phase/metal matrix, microhardness and wear resistance of the composite coating were analyzed and discussed. The results indicated that the in-situ ZrB2 ceramic had a needle-like morphology, the preferred growth direction was [(1) over bar(1) over bar 20], and the ZrB2 were coated with the Ni dendritic crystals. Ni formed an intermediate transition layer between the ceramic and the metal matrix. The submicron particle phases (ZrC) had a rectangular morphology in the copper matrix, and the side length was 500 nm. The hard ceramic fibers and particles were in-situ synthesized that were dispersed homogeneously in the metal matrix, which improved the mechanical properties of the coating. The mean value of the microhardness of the composite coatings was 410 HV0.2, which was nearly 6 times higher than that of the copper. The microhardness gradually decreased from the composite coating surface to the transition zone and then sharply dropped in the transition zone to the substrate. This trend agrees with the distribution of the ceramic reinforcements. The wear mechanism of the composite coating was a combination of abrasive wear and adhesive wear, and the wear volume loss was approximately 85% lower than that of the uncoated substrate.
10.1016-j.surfcoat.2020.126137	2	corrosion; surface; film; electrochemical; films; spectroscopy; layer; current; solution; potential; resistance; composition; x-ray; ions; showed	In this work, the effect of thiourea on the initial stages of the Cu-Sn electrodeposition in the potential range of the underpotential deposition (UPD) of tin from the sulphate electrolyte was studied by linear sweep voltammetry. The mechanism of Cu-Sn alloy nucleation and growth was proposed based on the results of chronoamperometry, chronopotentiometry, and scanning electron microscopy. Thiourea in the concentrations of 0.001-0.010 g/L showed a significant inhibitory effect on the reduction of copper ions. Analysis of the current-time dependencies revealed that Cu-Sn deposition in the UPD region of tin from thiourea-containing solutions proceeds through 3D diffusion-controlled growth of copper clusters. The nucleation type and the main nucleation parameters were calculated based on the Scharifker and Hills theoretical model. Galvanostatic experiments proved that the UPD of tin occurs on the surface of initially formed copper clusters. Surface characterization of Cu-Sn coatings deposited in the presence of thiourea showed a good correlation with electrochemical experiments.
10.1016-j.surfcoat.2020.126554	17	wear; composites; coating; friction; composite; coatings; surface; tribological; properties; wear resistance; resistance; powder; sliding; matrix; wear rate	In this work, graphene nanoplates(GNPs) reinforced Cu-Cr composite coatings were prepared by mechanical alloying(MA) method. In order to further improve the thermal performance, the coatings with different GNPs contents were annealed at 700 degrees C for 1 h . Raman, XRD and SEM were employed to characterize the defect of graphene, the phase transformation and the element distribution of coatings. Consequently, GNPs were detected to be well dispersed in the composite coatings. Moreover, the distributions of Cu and Cr were more homogeneous after annealing. In addition, chromium carbides formed in the coating during the annealing process, and the interfacial bonding in the coating would be further strengthened. Although the defects of GNPs increased during MA process, the thermal properties of as-synthesized samples were still greatly improved compared with Cu substrate.With the increase of GNPs content, the thermal conductivity of as-fabricated samples enhanced initially and then decreased. When the content of GNPs increased to 1.12 vol%, the highest thermal conductivity reached 424.210 W m(-1) K-1. This remarkable result might provide a new idea for GNPs reinforced thermal conductive materials.
10.1016-j.surfcoat.2020.126614	2	corrosion; surface; film; electrochemical; films; spectroscopy; layer; current; solution; potential; resistance; composition; x-ray; ions; showed	In this study, a Cu-Zn-Al/Zn-Al coating was prepared on Q235 steel by a dip-spin method and the corrosion behavior of the composite coating was also analyzed. The evolution of morphology and phase structure proved the corrosion products transited from the Zn-containing to Al-containing. The potential dynamic results manifested that the corrosion current density of the coated sample (1.42 x 10(-6) A.cm(2)) is two orders of magnitude lower than the substrate. From the impendence plots, it can be found that the impendence resistance of the original Cu-Zn-Al/Zn-Al coating is up to 1.58 x 10(4) Omega.cm(2) due to the existence of the silane and oxide film. With increasing exposure time of aggressive environment, the resistance decreased and then gradually rise to approximately 1.0 x 10(4) Omega.cm(2). Besides, the results of the antifouling test showed the copper leaching remained at a stable value of about 20 mu g.cm(-2).d(-1) which could inhibit most algae, eventually up to 95% lethal effect on N. closterium.
10.1016-j.surfcoat.2020.126804	16	wear; composite; composites; powders; milling; particles; powder; wt; sliding; friction; hardness; matrix; mechanical; surface; properties	With a 2.3-kW high-power diode laser, laser surface alloying of a commercially pure copper (cp Cu) with NiTi powder was carried out to attain higher corrosion and electrical wear resistances. Potentiodynamic polarization was conducted in simulated acid rain (SAR) at 25 degrees C for simulating the corrosive environment. In the SAR, corrosion potentials of all laser-alloyed samples are found to be nobler than those of cp Cu and NiTi alloy and their corrosion current densities are lower than that of cp Cu although their oxide layers are less uniform. Electrical wear tests were also carried out in both dry and wet conditions with a pin-on-disc tribometer. The electrical wear resistances of the laser-alloyed samples in wet condition are higher than in dry condition due to lubrication effect and reduction in frictional heat. The electrical wear resistances of all laser-alloyed samples were improved as compared with cp Cu owing to the presence of pseudo-plasticity of B19' and hard IMPs, and work hardening effect during electrical wear. The contribution of electrical wear in SAR is mainly mechanical wear, and wear-corrosion synergism up to 36.1%, while corrosion is negligible. Compared with cp Cu, the interfacial contact resistance of the laser-alloyed samples at 50 N/cm 2 has increased from 3.5 to 7.2 times.
10.1016-j.surfcoat.2021.126887	-1		The relatively weak interfacial bond and brittleness of cold sprayed deposits limit their industrial applications for the fabrication of complex structural components. In this study, pure copper, as a typical material for cold spray additive manufacturing (CSAM), was deposited and then post-processed with conventional heat treatment (HT) and newly developed electric pulse processing (EPP) and friction stir processing (FSP), in order to improve the microstructure and mechanical properties of the deposits. The results show that EPP, FSP, and HT can heal the weak interfaces between deposited particles, with EPP and FSP being considerably better than HT. Recrystallized fine grains and elongated grains at the interfacial regions transformed into coarser grains after EPP and HT. FSP refinement affects the grains of the whole deposit and completely rearranges the topology of the deposited particles. Mechanical tests reveal that an ultimate tensile strength of 310 MPa and elongation of 40% were reached after FSP, while the ultimate tensile strength of 209 MPa and elongation of 19% were reached with EPP. The main strengthening mechanisms of the EPP deposit are the improved bonding at the interfaces and the high angle grain boundaries and twins. For the FSP deposit, the improved interface bonding, the superfine grains along with the strain hardening effect are the main strengthening mechanisms.
10.1016-j.surfcoat.2021.126963	2	corrosion; surface; film; electrochemical; films; spectroscopy; layer; current; solution; potential; resistance; composition; x-ray; ions; showed	Marine biofouling is a critical issue significantly deteriorating the service performance of marine infrastructures. Thus, development of an effective and long-lasting antifouling coating is highly desirable. Here, a laminated-structured copper-titanium (CuTi) antifouling coating was fabricated by plasma spraying of mechanically blended Cu and Ti powders. The coating was designed to enable controlled release of Cu ions from Cu/Ti micro-galvanic cells and thus to achieve effective and long-term antifouling performance. The effect of Cu-Ti coating composition on its micro-galvanic dissolution behavior and antifouling performance was systematically investigated. The coating compositions were changed by varying Cu content from 8.1 to 65.2%. Analysis of scanning Kelvin probe force microscopy and long-term immersion test results indicated that Cu loading within Cu-Ti coating exhibited little influence on the formation and mechanism of Cu/Ti micro-galvanic cells. However, the Cu ions release rate and antifouling duration increased with increasing Cu loading. The antifouling efficiency of Cu-Ti coating against bacterial survival increased with the increase in the Cu loading from 8.1 to 19.2% and it reached similar to 100% when Cu loading exceeded 19.2%. Electrochemical test results revealed that with the variation of Cu loading, the amount of micro-galvanic cells rather than the dissolution rate of each single micro-cell played a more prominent role in deciding the total Cu dissolution rate; and consequently, the Cu ions release rate and self-polishing rate. These results may guide the advanced design of versatile Cu-Ti antifouling coatings with environment-friendly, durable, and remarkable antifouling capability for different practical requirements in marine engineering through facilely tailoring coating composition.
10.1016-j.surfcoat.2022.128561	-1		Reduced hardness and wear resistance may limit SAE C17200 copper-beryllium alloy use in manufacturing applications, such as plunger tips of die casting machines and as cores and inserts for steel dies in injection molding processes. In order to improve the surface properties of Cu-Be alloys, amorphous carbon (a-C) films have been selected since these coatings may show high hardness, low wear rate and low coefficient of friction. However, the adhesion of carbonaceous films on Cu-Be alloys remains a challenge. Two interlayer compositions (Ti/Si and Ti/TiN/Si) were deposited onto Cu-Be disks and silicon wafers to assess amorphous carbon adhesion on substrates made of Cu-Be alloy. The microstructure and topography of the coatings were examined by Field Emission Scanning Electron Microscopy (FESEM) coupled with X-ray dispersive energy spectroscopy (EDS). The chemical composition depth profile was measured by glow discharge optical emission spectroscopy (GDOES), which confirmed distinct coating layers of Ti, Si, a-C (C1 and C2 conditions-pDCMS). A TiN extra layer presence was obtained for the C3 and C4 conditions-pDCMS reactive, confirmed by small angle XRD analysis. Raman scattering spectroscopy showed a higher quantity of sp3 carbon bonds for C3 and C4 coating conditions compared to C1 and C2. Instrumented indentation tests indicated a higher hardness and reduced elastic modulus for C3 and C4 coating systems, corroborating Raman results, in terms of a higher concentration of sp3 bonds. Scanning electron microscopy (SEM), atomic force microscopy (AFM), and coherence correlation interferometry (CCI) were used to characterize the coatings' surface features and scratch tracks after the tests. In addition, ramp load scratch tests were conducted to assess coating adhesion to the Cu-Be alloy substrate by measuring critical loads and the coefficient of friction. The highest critical loads to failure (Lc2) and (Lc3) were found for the Ti/ TiN/Si interlayer sample (C4 condition), indicating that this interlayer improved the coating contribution to a gradual increase in the hardness and promotion of an enhanced adhesion strength of the a-C coating.
10.1016-j.surfcoat.2022.128568	2	corrosion; surface; film; electrochemical; films; spectroscopy; layer; current; solution; potential; resistance; composition; x-ray; ions; showed	A Cu/Ni-B4C superhydrophobic coating was fabricated on the surface of Q235 steel under different current density via electrodeposition. The distribution of electric field influenced by current density controls the growth of rough structure. Therefore, the effect of current density was measured by the morphology and wettability of coating and analyzed by Electric field distribution model. The coating surface demonstrates the most uniform and compact rough structure at a current density of 3 A/dm2 (MC-3) obtaining contact angle 160 +/- 2 degrees after the surface energy reduced by stearic acid. The self-cleaning performance and mechanical stability of MC-3 coating were studied. The potentiodynamic polarization curve (PPC) and electrochemical impedance spectroscopy (EIS) were used to measure the anti-corrosion and protection performance of the coatings with different morphology and contact angle. The protective performance of MC-3 coating soaked in 3.5 wt% NaCl solution for different time was studied by EIS. The wetting stability of different coatings was studied by single frequency impedance spectroscopy. Then the double protective mechanism of superhydrophobic coating was described and the corresponding model was established.
10.1016-j.surfcoat.2022.128720	-1		Uniform amorphous carbon films were deposited on polycrystalline copper substrate within a few minutes by a facile flame coating method. The effects of the flame coating process on the grain structure, corrosion resistance and mechanical properties of the metal substrate were investigated and compared with those of graphene counterpart via chemical vapor deposition (CVD). Due to the different heating temperature required for carbon deposition, it was found that the crystalline and grain structure of the Cu substrate varied with the deposition method, as well as their mechanical properties. Results indicated that the higher temperature, the larger metal grains formed and the lower hardness accordingly. Thanks to the lower temperature required for the flame coating approach, the hardness of the carbon coated Cu samples was much larger than that of graphene coated ones. Moreover, the corrosion current density of Cu with flame coating for 15 min declined sharply to be one thirtieth of that of bare Cu in 3.5 wt% NaCl solution, which was comparable to that of graphene coated sample. Furthermore, the oxidation resistance performance of both carbon and graphene coating as protective layer for Cu in hot air was also studied. Results indicated that the amorphous carbon had comparable protective performance with that of graphene layer and both of them slowed down the oxidation of Cu at elevated temperature. The corresponding corrosion mechanism was also proposed.
10.1016-j.surfcoat.2023.129260	-1		Among bronze alloys, strength and corrosion resistance are the distinguishing features of aluminium bronzes. Cu-Al alloys coatings are commonly prepared using thermal spraying technologies, but low-pressure cold spray, unpopular for this purpose so far, seems to be a good alternative in terms of manufacturing and facility costs. The research studies the effect of aluminium addition on low-pressure cold spray deposition of mixed Cu-Al feedstock powders (up to 30 wt% of Al) instead of bronze particles. Additionally, hard alumina particles (of the same weight as Cu-Al feedstock powders together) were added to lower coating porosity, provide good adhesion, and tailor the mechanical properties of coatings. After the implementation of thermal treatment, fine mixing of feedstock powders within the coating facilitated the formation of copper-rich solid solution and Cu4Al9 intermetallic phase for high amounts of Al (>= 25 wt%). The coatings were characterized through light and scanning electron microscopy to examine cross-section morphology; energy-dispersive X-ray spectrometry and X-ray diffraction to investigate elemental and phase composition before and after thermal treatment. Additionally, to quantify the individual phases in sprayed coatings Rietveld refinement was performed. For coatings after thermal treatment were bronze formation was observed, the maximum solubility of aluminium in the copper structure was also determined using Vegard's linear dependence.
10.1016-j.surfcoat.2023.129264	-1		Utilizing a laser cladding approach, three types of in-situ composite coatings (Cu-16Cr-4SiC, Cu-32Cr-8SiC, and Cu-48Cr-12SiC) were prepared on the CuCrZr alloy substrate. A biphasic structure as a result of the liquid-liquid phase separation (LLPS) were observed in the situ composite coatings, consisting of the Cr-rich phases (Cr3Si and Cr23C6) and the Cu-rich phase (Cu solid solution phase or kappa-Cu7Si phase). The in-situ composite coating's bilayer microhardness properties are therefore visible, and the microhardness of the Cr-rich zone (1149-1326 HV0.5) is up to around ten times that of the Cu-rich zone (125-284 HV0.5). With the decreased of Cu content, the diffused Cr-rich phase in the cladding coating were transitioned to a laminar segregation. More interestingly, this microstructure characteristic is related to the laser cladding process parameters. The predominant wear mech-anism of the coatings are hence delamination produced by matrix spalling along the friction surface. The wear rate of Cu-48Cr-12SiC coating is just 16.1 % of the substrate, with 6.9 % IACS conductivity.
10.1016-j.surfcoat.2023.129840	-1		The alloy coating is commonly used to enhance the hardness and wear resistance of Al substrate. However, the coating always cracks because of the brittle intermetallic compound (IMC) and thermal stress. In this investi-gation, the Ag buffer layer was employed to fabricate the crack-free Cu alloy coating. The effect of thickness of the Ag buffer on the phase transformation and hardness of Cu alloy coating was systematically investigated. The results showed that a thinner Ag buffer contributed to the dissolution of more Al and less Ag in the Cu alloy coating due to the dissolving of high-Al region of Ag buffer layer. A lower content of Ag in the Cu alloy coating brought more primary Cu-rich phase. The high Al in the Cu alloy coating contributed to the formation of 13 phase. During cooling stage, the 13 phase transformed into 13 & PRIME; phase through martensitic transformation. The more fine-grained 13 & PRIME; phase contributed to a higher hardness of 310 HV of the Cu alloy coating on the Ag buffer layer with a thickness of 450 & mu;m. The thicker buffer layer contributed to the coating with less Al and more Ag. The Cu alloy coating exhibited a microstructure with more eutectic phase. The primary Cu-rich phase became Cu solid so-lution due to the lower Al concentration. The coarse-grained primary Cu solid solution and low-hardness eutectic phase contributed to the low hardness of 275 HV.
10.1016-j.surfcoat.2023.129888	17	wear; composites; coating; friction; composite; coatings; surface; tribological; properties; wear resistance; resistance; powder; sliding; matrix; wear rate	Different types of Mo coatings were prepared on the surface of a copper alloy via laser cladding technology in this study to address the problem of low hardness of copper alloy current-carrying friction subsets. Meanwhile, the problems of high reflectivity of copper alloy materials to infrared laser light and mutual insolubility of Cu and Mo were solved by introducing an intermediate layer structure, and the coating process was optimized to obtain a coating with excellent formation. The microstructure, hardness, and interfacial shear bond strength of coatings were tested. Results showed that the Mo coating prepared using a plasma-spheroidized powder had a lower dilution rate and finer and tighter grain growth compared with the Mo coating prepared by crushing agglomerated powder. The coating phase mainly consisted of Mo, Ni3Mo, MoO2, and Cu0.81Ni0.19. The unfused particles present in the plasma-spheroidized powder coating acted as a second hard reinforcing phase, which could significantly increase the hardness of the coating. Three kinds of coatings exhibited strong bond strength, and coatings prepared from different powders fractured in diverse ways. In sum, the plasma-spheroidized Mo coating prepared using the three-way powder feeding method not only had good formation but also possessed the most excellent mechanical properties.
10.1016-j.surfcoat.2023.130121	-1		A superhydrophobic Cu-Co coating is successfully applied to the surface of a B10 copper-nickel (Cu-Ni) alloy welded joint via electrodeposition and modification using a low-surface-energy material (stearic acid). The static water contact angle is measured to be 162.2 +/- 1 degrees, and the roll off angle is 2.1 degrees. Various techniques, including scanning electron microscopy, energy dispersive X-ray spectroscopy, X-ray diffraction, X-ray photoelectron spectroscopy, and Fourier-transform infrared absorption spectroscopy are employed to characterize the chemical composition and phase structure of the samples before and after electrodeposition and modification. The corrosion resistance of the superhydrophobic samples is evaluated via electrochemical impedance spectroscopy, potentiodynamic polarization, and scanning Kelvin probe microelectrochemistry. The results indicate that the superhydrophobic coating exhibits greater charge transfer resistance, lower self-corrosion current density, and higher surface work function, thus effectively enhancing the corrosion resistance of the B10 Cu-Ni alloy welded joint. Furthermore, the micro-nano rough structure with low surface energy on the superhydrophobic sample surface traps air and forms an air layer, thereby reducing the contact between the corrosive medium and welded joint as well as minimizing corrosion. The superhydrophobic coating demonstrate thermal stability as well as excellent self-cleaning and mechanical properties, based on comprehensive testing and analysis.
10.1016-j.surfcoat.2024.130706	-1		Laser powder bed fusion (LPBF) technology presents significant potential for the production of metallic glass (MG) coatings. This work investigated the influence of laser power on the structure and wear performance of a CuZr-based metallic glass coating with composition of Cu 45 Zr 45 Al 6 Ti 4 on Ti substrate. It was observed that the melt pool, which serves as the fundamental building block for constructing MG coatings in LPBF, undergoes a transition from conduction mode to keyhole mode, and subsequently to extended mode with increasing laser power. The MG coatings prepared using low power laser (140 W) and medium power laser (240 W) both exhibited a nearly fully amorphous state. However, at a laser power of 360 W, noticeable crystallization occurred in the coating, as evidenced by SEM observation. The wear rate of Cu 45 Zr 45 Al 6 Ti 4 MG coating was measured to be 4.67 x 10 -6 mm 3 & sdot; N-1 & sdot; m-1 , which is significantly lower than that of the Ti substrate (6.38 x 10 -4 mm 3 & sdot; N-1 & sdot; m-1 ). This study reveals the relationship between the laser power and morphology of the melt pool, as well as the structure and wear performance of the LPBF-fabricated MG coatings, offering guidance for optimizing the laser additive manufacturing process of wear-resistant MG coatings.
10.1016-j.surfcoat.2024.130989	-1		To enhance the current -carrying tribological properties of the Cu/Al friction pair, Ni-based transition -coatings and Mo-based function -coatings were sequentially prepared on copper alloys by laser cladding. The microstructure, mechanical properties, electric conductivity, and current -carrying tribological properties of the coatings were comprehensively investigated. The function -coating consisted of a Mo-rich layer and a high -dilution layer, with a close metallurgical bond formed between the layers. Compared with the substrate, the average microhardness (640.2 HV 0.2 ) and elastic modulus (320.9 GPa) of the Mo-rich layer were increased by 326.8 % and 89.7 %, respectively. The substrate after cladding with the Mo-based coating demonstrated an acceptable conductivity as 78.30 %IACS. The transition -coating infiltrated moderately into the function -coating, promptly filling cladding defects, enhancing grain boundary toughness, and effectively mitigating the significant mechanical property differences between the Mo-rich layer and the substrate. Current -carrying friction tests with the Al friction pair indicated that, under low currents (10 A), the Cu substrate was prone to both adhesive wear and abrasive wear, while the function -coating only exhibited slight abrasive wear. Under high currents (40 A), the Cu substrate experienced severe mechanical wear and electrical wear. Nevertheless, the function -coating still suffered slight abrasive wear with a wear volume of only 1/33 of the substrate owing to the protection and lubrication of the Al adhesion film and the good contact state.
10.1016-j.surfcoat.2024.131287	-1		The copper (Cu) alloys are prone to severe corrosion in marine environments. In this work, we successfully develop a novel high corrosion-resistant and superhydrophobic MAO-30/PA/VTES composite coating on Cu-15Fe-15Fe alloy for long-term corrosion protection. The composite coating, with a corrosion rate of 0.00001 mm/ y and a water contact angle of 152.7 degrees, degrees , presents significant advantages over most Cu alloys modification methods to date. Benefiting from the modification with phytic acid (PA) and vinyltriethoxysilane (VTES), the corrosion current density of the composite coating remains 2.14 x 10-10 A center dot cm-- 2 even after 168 h of immersion in 0.6 M NaCl, which is four orders of magnitude lower than Cu-15Fe-15Fe substrate (5.68 x 10-6-6 A center dot cm-2).- 2 ). The exceptional long-term corrosion resistance of the composite coating is attributed to the physical barrier effect of the micro- arc oxidation (MAO) layer, the superhydrophobic characteristics and sealing effect of the PA/VTES film layer, and the chelating effect of the phytic acid. Developing the composite coating introduces a new approach to protecting Cu alloys from corrosion in marine environments.
10.1016-j.surfcoat.2024.131289	17	wear; composites; coating; friction; composite; coatings; surface; tribological; properties; wear resistance; resistance; powder; sliding; matrix; wear rate	To satisfy the need for high wear resistance of Inconel718 alloy under harsh working conditions, laser cladding technique was adopted to fabricate the Cu/Ti3SiC2-CoCrW 3 SiC 2-CoCrW metal matrix composite coatings on that surface. The phase composition, microstructure, microhardness, surface energy, and tribological properties of the composite coatings were systematically analyzed by characterization methods such as XRD/ SEM/ EDS/ XPS and performance test methods such as high-temperature friction and wear test, and the wear mechanism at different temperatures was deeply discussed. The research results indicate that the microhardness of coatings is increased by 2.2-2.9 times compared to the substrate, which is mainly owing to the solid solution strengthening effect and the diffusely distributed hard reinforcing phases such as Cr7C3, 7 C 3 , WCx, x , and TiC. Regarding the wear resistance, the wear rate of coatings is significantly reduced by 1-2 orders of magnitude over the substrate. Among them, the Co-based coating adding 10 wt% Cu- 10 wt% Ti3SiC2 3 SiC 2 exhibited the lowest wear rates at room and high temperatures, which were 0.22 and 3.23 x 10-5-5 mm3/ 3 / N & sdot;m, respectively, with 98.22 % and 88.19 % reductions in comparison with the substrate. The low surface energy (27.94 mN/m) was one of the main reasons for the good tribological properties. When the friction environment changes from room temperature to 600 degrees C, the primary wear mechanism of coatings changes from abrasive and adhesive wear to oxidative wear.
10.1016-j.surfcoat.2024.131661	14	strength; properties; conductivity; electrical; mechanical; cu-; grain; mpa; electrical conductivity; aging; precipitation; phase; mechanical properties; tensile; phases	The aim is to improve the lubricating properties of surface of the joint hoop of the sucker rod In the oil industry. To achieve this, composite coatings of CuNi25 alloy, incorporating varying amounts of copper-plated graphite, were applied to 40Cr steel substrates utilizing the laser cladding technique. The surface morphology, crosssectional morphology, and composition of the coatings were examined to assess the impact of friction and wear performance on the copper-plated graphite-CuNi alloy self-lubricating coatings, as well as to elucidate the wear mechanisms involved. The resulting coatings exhibit a dense surface with uniform thickness, demonstrating excellent self-lubricating and wear-resistant properties during friction with counterpart components. As the proportion of copper-plated graphite rises, the quantity of graphite particles adhering to the surface of the coating also increases, thereby functioning as a solid lubricant. The mean microhardness of the coatings exhibited an increase from 245.2 HV0.2 to 395.1 HV0.2, accompanied by an enhancement in the wear resistance of the coating surfaces. However, it was observed that as the friction frequency increased, the resistance to deformation diminished, the coefficient of friction decreased, and the self-lubricating properties were enhanced. It has been determined that the wear resistance and self-lubricating characteristics of copper-plated graphite-copper-nickel alloy self-lubricating coatings are influenced by the refinement of graphite particles and grains present on the surface of the coatings. The presence of graphite facilitates the refinement of grains within the coatings, thereby enhancing their hardness and wear-reducing capabilities. Furthermore, the predominant mode of wear observed in these coatings is identified as abrasive wear.
10.1016-j.surfcoat.2024.131666	-1		When used in marine engineering, copper (Cu) and its alloy components are prone to corrosion and wear, eventually reducing their operational lifespans. In this study, Cu-based Cu@AlN composite coatings were cold sprayed on T2 Cu substrate by using electroless plated Cu-coated aluminum nitride (Cu@AlN, with 0 (P0), 10 (P1), 20 (P2), and 30 (P3) vol%) and Cu powders as the feedstocks. The microstructure, microhardness, tribological property, and corrosion resistance of the composite coatings were investigated by various evaluation methods. Results indicated that the Cu electroless plating layer increased the AlN ceramic retention in the composite coatings up to 28 %. The increased ceramic content in the composite coating led to a denser microstructure and increased microhardness compared to Cu coating. However, a higher content of ceramic particles aggregated in the P3 coating and led to increased porosity and decreased hardness. The porosity and hardness of the P2 coating showed an 85.7 % decrease and a 44.8 % increase than that of the Cu coating. The variation in porosity and hardness facilitated the better wear resistance of P2 among all the composite coatings. In addition, the electrochemical test results showed that the porosity, uniformity, and content of reinforcements in the composite coating were the main factors affecting their corrosion resistance.
10.1016-j.surfcoat.2025.132233	-1		In electromagnetic launch systems, the harsh service conditions coupling of electrical arc erosion, high temperature friction and high frequency of thermal shock make the surface of the high strength Cu alloy rail easily damaged. The conventional high-strength alloy repair layer faces challenges in balancing electrical conductivity with wear and arc erosion resistance. Addressing this challenge, in the present work, a novel multilayered repairing strategy is introduced by cold spraying pure Cu and Cu-based composite deposits for synergistically improving/balancing the adhesion, electrical conductivity and surface protection performance. The effects of the multilayered deposit structure design, strengthening particle surface modification, and heat treatment on adhesion, electrical conductivity, wear and arc erosion resistance of the deposits are investigated. An optimized multilayered structure composed of a Cu-WC bond coat, a pure Cu middle layer and a composite top layer deposited with Cu-Ni-clad W (Ni@W) powder is achieved. As compared with spraying pure Cu, an increase in adhesion from 14 MPa to 66 MPa is achieved via introducing Cu-WC composite bond coat on the CuCrZr substrate. For the top composite layer, as the Ni@W particles are used to strengthen pure Cu, the friction coefficient and wear rate decreases from 0.37 and 3.2 x 10-5 mm3 center dot(N center dot m)- 1 to 0.14 and 2.3 x 10-5 mm3 center dot(N center dot m)- 1, respectively, and the arc erosion depth and area decreased by 31.1 % and 81.0 % with the breakdown intensity improved by 50.6 % relative to the CuCrZr substrate. Meanwhile, a high electrical conductivity of 77.7 %IACS through the thickness direction is detected for the optimized multilayered deposit. Finally, a practical repair demonstration done on V-grooved CuCrZr substrates confirms the structural integrity and machinability of the cold sprayed multilayer composite deposit. The present work is attempted to offer a viable solution for improve the service performance and extending the service life of the metallic structures used in coupled harsh conditions.
10.1016-j.surfin.2019.100404	2	corrosion; surface; film; electrochemical; films; spectroscopy; layer; current; solution; potential; resistance; composition; x-ray; ions; showed	In the present work, glutamate ions were applying as a complexing agent in codeposition of Cu-Zn alloy coatings from a non-cyanide acidic sulfate bath at room temperature. The effect of Cu2+/Zn2+ concentration ratios as well as the glutamate ion concentrations on the morphology, structure, and microhardness of the alloy coatings was studied. Electrochemical analyses were implemented using cyclic voltammetry and anodic linear stripping voltammetry. It was found that glutamate ions decrease cathodic overpotential for the reduction of Zn2+ ions and enhances cathodic overpotential for the reduction of Cu2+ ions. Consequently, the simultaneous codeposition of Zn2+ and Cu2+ ions were facilitated and copper-rich Cu-Zn alloy coating was achieved. Characterization of Cu-Zn alloy coatings was carried out using SEM and XRD. The Cu-Zn alloy deposited from the glutamate complex bath consisted mainly of one phase alpha-CuZn. The morphology of Cu-Zn alloy significantly depends on the Cu2+/Zn2+ concentration ratios, glutamate ion concentrations as well as on the operating conditions as shown by SEM investigation. Moreover, Cu-Zn alloy coating deposited from these baths possesses microhardness ranged from 115 to 250 kg mm(-2) depending on the bath composition and the operating conditions.
10.1016-j.surfin.2020.100466	2	corrosion; surface; film; electrochemical; films; spectroscopy; layer; current; solution; potential; resistance; composition; x-ray; ions; showed	The electrodeposition of Cu-Sn-Zn coating (CZT) was investigated. The bath consisted of aqueous solution of Cu, Sn and Zn sulphate in the presence of sodium citrate (NaC6H5Na3O7) as complexing agent. The pH was set between 4 and 5.5 to stabilize the bath . Cyclic voltammetry exhibited four peaks during cathodic scan corresponding to the reductions of metal ions and adsorbed hydrogen. Impedance measurements were made at each potential peak. The effect of the metal salts concentration and the potential scan rate were studied. The deposit mechanism is controlled by mass transfer in parallel with a faradaic reaction. For the deposition of Cu-Sn and Cu-Sn-Zn alloys, the average diffusion coefficients of Cu2+ and Sn2+ ions and Cu2+, Sn2+ and Zn2+ ions were calculated. At E=-1.5 V, a Cu-Sn-Zn deposit is obtained with 55 at% copper, 25 at% tin and 20 at% zinc. The X-ray diffraction pattern shows the characteristic peaks of Cu, Cu6Sn5 and Cu3Zn2 phases. The deposit morphology was characterized by SEM.
10.1016-j.surfin.2020.100742	-1		In the present work, a novel system of Cu2AlNiZnAg high entropy alloys (HEAs) powder was successfully synthesized and Cu-Cu2AlNiZnAg/diamond coatings were fabricated on T2 pure Cu substrate via mechanical alloying method. Characterization of the Cu2AlNiZnAg HEA powder indicated that a single FCC solid solution phase was formed and no indication of any amorphous phase or intermetallic compound was found in the microstructure. The FCC phase was Cu-rich phase. The coatings exhibit a microstructure composed of black particles of diamonds and gray areas of Cu2AlNiZnAg HEA reinforced Cu matrix composites. The effects of CuCu2AlNiZnAg/diamond ratio and milling time on the fabrication of coatings were investigated. The effect of annealing treatment on the microstructure of coatings was discussed. The microhardness of the coating was far higher than that of copper substrate whether it was annealed or not. The thermal conductivity of the fully coated sample was improved greatly after annealing, reaching 358.53W.m(-1).K-1, which was superior to the T2 pure copper with the same annealing treatment.
10.1016-j.surfin.2021.101599	17	wear; composites; coating; friction; composite; coatings; surface; tribological; properties; wear resistance; resistance; powder; sliding; matrix; wear rate	Cu-10Al coatings with the different MoS2 mass fractions were fabricated on Q235 steel using laser cladding (LC). The surface morphologies, chemical compositions and phases of obtained coatings were analyzed using a scanning electron microscope (SEM), energy dispersive spectroscopy (EDS), and X-ray diffraction (XRD), respectively. The effects of MoS2 mass fraction on the microstructure and friction and wear properties under the oil-lubrication condition were studied, and the wear mechanism was also discussed using a plane scan analysis. The results show that the laser cladded Cu-10Al coatings with the different MoS2 mass fractions were mainly composed of solid solution phases of Cu0.78Al0.22 and intermetallic compound of Cu9Al4 and AlFe3. The average coefficient of frictions (COFs) of Cu-10Al-4%MoS2, 8%MoS2 and 12%MoS2 coatings are 0.195, 0.158, and 0.124, respectively, which decease with the MoS2 mass fraction; and the corresponding wear rates are 2.54 x 10(-7), 1.29 x 10(-7), and 1.98 x 10(-7)mm(3).N-1.m(-1), respectively, the wear rate of Cu-10Al-8%MoS2 coating is the lowest among the three kinds of coating, the main wear failure mode are abrasive wear and adhesive wear.
10.1016-j.surfin.2022.102076	-1		This paper investigated the wettability of molten Cu-8.6Zr-xTi (x = 0, 10, 15, 20 at%) alloys on Si3N4 substrate using a modified sessile drop method at 1100 degrees C. In situ examinations of contact angles, and normalized contact radii indicated liquid Cu and Cu-8.6Zr alloy could not wet Si3N4. Excellent wetting of molten Cu-Zr-Ti on Si3N4 substrate was induced by adding Ti and further the TiN, Ti segregation layer, and Ti-Zr-Si compounds presented at the solid/liquid interface. On the other hand, spreading dynamics were determined mainly by the interaction of molten alloys and solid ceramic at the interface and appeared in two periods, which correspond to the decomposition of Si3N4 and the precipitation of the Ti-nitride reaction layer, respectively. Besides, the adsorption of active element Ti at the interface improved the wettability to some extent.
10.1016-j.surfin.2023.103224	-1		In this a multiphase cubic system has been successfully synthesised by solvothermal method. The profile fitting using Rietveld refinement confirms the phase fraction of monoclinic-Cu4Bi5S10, orthorhombic-Cu3BiS3, orthorhombic-Sb2S3 and tetragonal- Cu3SbS4 as 54.56%, 40.33%, 2.96%, 2.15%, respectively. Further, the presence of multiphase was additionally confirmed using HR-TEM analysis from observing the various patterns of atomic arrangement in the lattice plane. Moreover, a narrow band gap of 0.64 eV was confirmed using UV-DRS analysis. Electrical transport properties such as the Seebeck coefficient and electrical conductivity has been determined using ZEM-3 measurement which depicts the negative value of the Seebeck coefficient that conforms to the negative charge carrier transport. Interestingly the very low thermal conductivity of 0.37 Wm- 1K-1 at 303 K is observed for the S2 sample. Overall, with enhanced electrical conductivity of 59.7 S.cm- 1 at 473 K, and Seebeck coefficient of 60.3 & mu;VK-1 at 353 K leads to a maximum ZT of 0.0068 at 473 K, which is due to the synergistic effects of boundary phonon scattering, energy filtering and modulation doping effect in the multiphase Cu-Bi-SbS system.
10.1016-j.surfin.2023.103799	2	corrosion; surface; film; electrochemical; films; spectroscopy; layer; current; solution; potential; resistance; composition; x-ray; ions; showed	In the present research, we explored the corrosion inhibition mechanisms on metals and alloys by imidazole, methylimidazole, and benzimidazole applying density functional theory (DFT), reactive (ReaxFF), and classical force fields. Our investigation focused on the interaction of these molecules with different types of bare metal surfaces. The results of our studies have been compiled to compare the protection efficiency of the three organic molecules for copper, zinc, and copper-zinc alloys (Cu-63%-Zn-37%) exposed to the same corrosion conditions in an acid environment. The calculated interaction energy quantities are strongly correlated with the experimental corrosion inhibition efficiencies BIM > MIM > IM. The imidazole derivative studied, significantly better protect copper than zinc, which is attributed to the higher bond strength of Cu-N (formation of chemical bonds) than of Zn-N, confirms the increase in the protection effectiveness against corrosion of Zn < Cu-63%-Zn-37% < Cu. This present study demonstrates the enormous potential of ReaxFF calculations to accurately simulate the adsorption of inhibitor molecules onto metal surfaces at a fraction of the computational cost of DFT, as well as the performance of the umbrella sampling method to assess the adsorption free energies.
10.1016-j.surfin.2025.105861	14	strength; properties; conductivity; electrical; mechanical; cu-; grain; mpa; electrical conductivity; aging; precipitation; phase; mechanical properties; tensile; phases	This study successfully synthesized a honeycomb-structured Cu-B alloy through solidification conditions. The microstructure of the honeycomb-like Cu-B alloy revealed the coexistence of crystalline and amorphous phases, exhibiting a characteristic honeycomb structure. In testing conducted in 0.6 mol/L HCl and 0.6 mol/L NaCl solutions, the honeycomb Cu-B alloy has excellent corrosion resistance compared with Cu-30Ni alloy. The hardness of the alloy reached 3.8 GPa, surpassing other Cu-based alloys and alloys with good corrosion resistance. Additionally, the honeycomb-like Cu-B alloy showed excellent antimicrobial activity against Pseudomonas aeruginosa. Consequently, the honeycomb-structured honeycomb-like Cu-B alloy is deemed suitable for the demanding corrosive environments encountered in offshore engineering applications.
10.1016-j.surfin.2025.106241	-1		Deep eutectic solvents (DESs) provide enormous opportunities for manufacturing functional, electronegative metal alloys with hierarchical structures-because of the broad working windows for electrochemical reactions and the advantages of multiscale directing chemistry. This work presents the electrodeposition preparation of a hierarchical-structured Cu-Zr amorphous alloy coating from ChCl-EG DES for the first time. The electrochemical behavior of Cu2+ and Zr4+, and the comprehensive microscopic and structural characterizations of the obtained deposits, demonstrate a potential-dependent nucleation and growth mechanism of Cu and Zr species on the surface of Cu foil. The deposits yielded at the lower negative potentials containing small amounts of Zr (< 4.0 at%) are two-phase, with fibrous CuaZrbOc compounds cross-growing on the surface of the leaf-like face-centered cubic Cu phase. In contrast, the deposit obtained at a higher negative potential presents a Christmas tree-like Cu-Zr amorphous alloy structure (9.03 at% Zr), and the hierarchical multiscale ZrO2 amorphous layer formed on its surface can enable the native alloy with better corrosion resistance.
10.1016-j.surfin.2025.107138	-1		Submicron TiC and nano-TixO (x = 1, 2) particle-reinforced Cu-based composite coatings were synthesized in situ via simultaneous solid-solid and solid-gas reactive plasma spraying (RPS) using Cu-Ti-C composite powder. The coatings consist of submicron TiC particle-reinforced Cu-based lamellae, nano-TixO particle-reinforced Cu-based lamellae, TixO lamellae, and residual graphite. The reaction mechanism can be summarized as follows: First, the Cu-Ti powder melts and wraps the graphite to form droplets. The carbon (C) from the graphite dissolves into the liquid phase and reacts with titanium (Ti) during flight to form submicron TiC particles. TiC particles disperse into the solidified CuTi matrix under impact to form submicron TiC particle-reinforced Cu-based lamellae. Oxygen from the atmosphere dissolves and diffuses into the droplets, creating a gradient of decreasing O concentration from the outer to the inner layer. With a lower O concentration, the inner layer solidifies into nano-TixO particle-reinforced Cu-based lamellae. In contrast, with a higher O concentration, the outer layer solidifies into TixO lamellae under impact. The coatings exhibit greater hardness and wear resistance than CuCrZr alloy due to the reinforcing effects of TiC and TixO particles. The wear mechanisms of the CuCrZr alloy and the coatings are mainly oxidation wear and adhesive wear, respectively.
10.1016-j.susc.2006.10.016	-1		The alloying process of Ti deposited on Cu(001) was studied by means of XPS, LEIS, XPD and LEED intensity analysis. With the sample held at 570 K, a linear decrease of the Cu LEIS signal as a function of the amount of Ti deposited is observed in the early stages of deposition until a constant value is reached. At the onset of the plateau a c(root 2 x 5 root 2)R45 degrees LEED pattern starts to be visible. XPD and LEED intensity measurements were performed for the c(root 2 x 5 root 2)R45 degrees phase prepared depositing ca. 1.5 monolayer of Ti. The angle-scanned XPD curves measured for the phase c(root 2 x 5 root 2)R45 degrees reveal that Ti atoms substitute Cu atoms in the fcc lattice of the substrate. The polar XPD curves show that at least the first four layers of the substrate are involved in the alloying process. We found that the (310) plane of the CU4Ti alloy (D1a type-structure) fits, without significant contraction or expansion of the lattice parameters, the c(root 2 x 5 root 2)R45 degrees structure. The intensity versus energy curves of the diffracted beams were calculated on the basis of this structural model using the tensor LEED method. The results of the LEED intensity analysis provide a further evidence of the formation of a slab Of CU4Ti(310) layers.
10.1016-j.susc.2007.01.050	-1		Scanning tunneling microscopy (STM) has been used to study the various possible structures of adsorbed Bi on the Cu(1 0 0) surface, after equilibration at a temperature of 520 K. All of the structures previously identified by X-ray diffraction (lattice gas, c(2 x 2), c(9 root 2 x root 2)R45 degrees, and p(10 x 10), in order of increasing Bi-coverage) were found to be present on a single sample produced by diffusing Bi onto the Cu(1 0 0) surface from a 3-d source. By investigating the possible coexistence of various pairs of phases, it was demonstrated that the c(2 x 2) phase transforms to the c(9 root 2 x root 2)R45 degrees phase by a first order transition, whereas the transition from c(9 root 2 x root 2)R45 degrees to p(10 x 10) is continuous. In addition, the structure of surface steps was studied as a function of Bi-coverage. The results showed that the presence of Bi changes the nature of the step-step interactions at the Cu(1 0 0) surface from repulsive to attractive. The attractive step-step interactions transform any small deviations from the nominal (1 0 0) orientation of the Cu substrate into (3 1 0) microfacets. When compared with the known equilibrium crystal shape (ECS) of Bi-saturated Cu, the observed microfaceting may imply that the ECS of Cu-Bi alloys is temperature dependent.
10.1016-j.susc.2007.04.250	-1		In this work, surface segregation to Cu3Pt surfaces is studied with the modified embedded atom method (MEAM). This work is triggered by the catalytic importance of Cu-Pt alloys, together with the contradictory experimental results for the surface segregation in Cu3Pt(1 1 1) alloys based on low energy ion scattering (LEIS) [Y.G. Shen, D.J. O'Connor, K. Wandelt, R.J. MacDonald, Surf. Sci. 328 (1995) 21] and low energy electron diffraction (LEED) [Y. Gauthier, A. Senhaji, B. Legrand, G. Treglia, C. Becker, K. Wandelt, Surf. Sci. 527 (2003) 71]. In order to accurately describe the segregation behaviour in the Cu3Pt system, a reliable potential, that is also applicable to surface phenomena, is indispensable. Therefore, first, new MEAM parameters are derived, consistently based on ab initio density functional theory (DFT) calculations, according to a method that is a modification of previous work [P. van Beurden, G.J. Krarner. Phys. Rev. B 63 (2001) 165106]. Upon testing, these parameters prove to reproduce very well various surface properties of this system. Next, Monte Carlo (MC) simulations combined with the newly derived MEAM potentials are set up to investigate surface segregation to low index single crystal surfaces. For the Cu3Pt(1 1 1) surface, our MC/MEAM simulations agree completely with the available LEIS evidence and contradict the unusual depth profile based on LEED. However, the slight Pt enrichment observed in the LEED experiments can be reproduced by assuming a slight Pt excess in the bulk of the sample. The simulated composition depth profile, on the other hand, does not agree with the LEED evidence. Also, for the Cu3Pt(1 0 0) surface, the MC/MEAM results agree completely with LEIS experiments. For the Cu3Pt(1 1 0) surface, finally, the MC/MEAM simulations show a somewhat deviating behaviour with respect to the experimental LEIS evidence. The possibility of a missing-row reconstruction is evaluated, but cannot explain the discrepancy for the Cu3Pt(1 1 0) system. In order to further investigate the deviation from the experiments, additional DFT and MEAM calculations are performed in search of the preferred surface termination for Cu3Pt(1 1 0). Both DFT and MEAM calculations agree on the pure Cu layer as the most stable surface termination. Although the experiment was extensively tested for reproducibility, it possibly reflects a metastable state. Finally, in view of the importance of small and less orderly particles in catalysis, the newly derived MEAM parameters are used in order to study the segregation to Cu3Pt vicinal surfaces with {1 1 1} terraces, for which no experimental information is available yet.
10.1016-j.susc.2009.01.014	-1		Auger electron spectroscopy (AES) and low energy electron diffraction (LEED) were applied to investigate the segregation of aluminum atoms on a Cu-9 at% Al(1 1 1) surface. We observed that the Al concentration in the top layer ranged between about 9 and 36 at% after the sample we used was annealed at different temperatures. The phenomenon of Al atoms segregating on the surfaces was explained well by considering the diffusion length of Al atoms in bulk Cu. LEED measurements showed that (root 3 x root 3)R30 degrees structures grew as the concentration of A] atoms increased. The segregation phenomena on surfaces resulted in a stable two-dimensional Cu(67)Al(33) alloy phase in the top layer.
10.1016-j.susc.2009.07.011	12	thermodynamic; ternary; phase; data; experimental; equilibria; phase equilibria; liquid; binary; experimental data; calculated; phases; literature; model; calphad	The study of the thermodynamic and the surface properties of liquid Cu-B alloys can help better understanding of a complex interfacial chemistry related to liquid Cu-brazes in contact with boride substrates. Despite a simplicity of the Cu-B phase diagram, only a few thermodynamic data are available in the literature, while in the case of the surface properties a complete lack of data is evident. The quasi-chemical approximation (QCA) for the regular solution has been applied to describe the mixing behaviour of liquid Cu-B alloys in terms of their thermodynamic and surface properties as well as the microscopic functions. In view of joining processes related to liquid Cu-brazes/solid boride systems a particular attention is paid to the surface properties of the Cu-rich part of the system and the calculated values are substantiated by the new surface tension experimental data of liquid Cu and Cu-10 at% B alloy. The tests have been performed by the sessile-drop method under the same experimental conditions. Considering the experimental uncertainties, the effect of oxygen on the surface tension of liquid Cu and Cu-10 at% B alloy has been analysed by simple model that combines the physical property data included in Butler's equation with the oxygen solubility data and it gives the same results as Belton's adsorption equation.
10.1016-j.susc.2010.10.009	-1		The normal and lateral spring constants of rectangular silicon AFM cantilevers bearing pyramidal silicon tips were accurately calibrated using a procedure that takes into account their tilt compared to horizontal orientation and their trapezoidal cross section. Such systems were used to carry out nanoscratching tests in air on technical substrates presenting a moderate roughness (RMS approximate to 40 nm) and made either from bulk copper or from cuprous oxide thin films electrogenerated on copper. The various events occurring during these nanoscratching procedures were characterized in details. In particular, the features of the scars appearing on the scratched zones and SEM observations of the AFM tips used during the nanoscratching procedures are described and exploited to establish a better understanding of the effects of the nanoscratching procedures on the targeted samples. In the case of electrodeposited Cu2O films, these effects are discussed with the help of chemical and structural characterizations using XPS and XRD studies. All this set of information is used i) to describe the history of the nanoscratching tests and ii) to compare mechanical resistance of bulk copper and electrogenerated Cu2O thin films using these nanoscratching tests carried out in air. The wear mechanism occurring during nanoscratching tests is discussed for both kinds of samples and compared with the one observed during erosion in erosion-corrosion tests.
10.1016-j.susc.2016.01.013	-1		Using density functional theory (DFT) and Monte Carlo (MC) simulations, we studied the surface segregation phenomena of Au atoms in the extended and nanoparticle surfaces of Cu-Au alloys. Our MC simulations predicted significant Au enrichment in the outermost layer of (111) and (100) extended surfaces, and Au enrichment in the two outermost layers of (110) extended surfaces. The equilibrium Cu-Au nanoparticles were predicted to develop into an Au-enriched shell structure, where Au atoms preferably segregate to the (100) facets while Cu atoms are mainly located on the (111) facet of the nanoparticles. Our simulation predictions agree with experimental measurements.
10.1016-j.tafmec.2015.12.015	6	grain; deformation; strain; strength; dislocation; cu-; tensile; size; ecap; grain size; sfe; ductility; hardening; high; stress	In this study, the fatigue behavior of Cu-2.55Ni-055Si alloy specimens was investigated by fracto-graphical analysis. Fatigue specimens were prepared according to ISO 1099 standard and constant amplitude loading was applied at a stress ratio (R = sigma(min)/sigma(max)) of R = -1. The criterion set for the termination of the fatigue tests was either the fracture of the specimen or the limit of 5E6 fatigue cycles. Tests were carried out at different stress levels to determine the stress-lifetime curve (S-N curve) of the material. The fatigue limit was evaluated at 179 MPa. All tested surfaces were examined by scanning electron microscope to characterize the fracture behavior. In general, metal silicides, as well as grain and twin boundaries contributed to crack propagation. The fracture surfaces exhibited typical tracks indicating dimple rupture, intergranular/transgranular rupture and fatigue rupture as a function of the applied sigma(max).
10.1016-j.tafmec.2022.103262	4	transformation; martensite; martensitic; phase; shape; beta; memory; shape memory; temperature; temperatures; martensitic transformation; gamma; transformation temperatures; effect; thermal	Deformation of a Cu-Pd-P amorphous alloy is studied under periodical mechanical load (stress/unload cycle with 0.3 Hz or 3 Hz frequency) on heating at the constant rate of 5 K/min. We show that deformation of the material is interpolated with a hyperbolic function of time or temperature. As predicted non-isothermal cyclic deformation takes place with wave effects, which are a result of the combination of heating and cyclic mechanical loading. A reaction force graph of alloy was analysed as a surface with two variable parameters: loading frequency and time. The proposed model describes the resonance processes from the standpoint of non-linear dynamical systems.
10.1016-j.tafmec.2024.104571	-1		The tensile as well as the fatigue behaviour of an experimental copper-alloyed metastable austenitic stainless steel has been investigated. Three batches were studied: (i) cast material as reference state and two states were recrystallised after (ii) rotary swaging and (iii) forward impact extrusion. Deformation-induced alpha'-martensite was formed during both rotary swaging and forward impact extrusion with volume fractions of 48 vol% and 4 vol %, respectively. The material was then heat treated to form a fine-grained, fully austenitic microstructure. These fine-grained material states exhibited a higher strength compared to the cast state. However, strain-hardening was highest in the cast state. The effect of the initial microstructure on the cyclic deformation behaviour and fatigue life was investigated using strain-controlled tests. During cyclic deformation all three states exhibited a martensitic phase transformation and concurrently a pronounced cyclic hardening with the formation of up to approximately 70 vol% alpha'-martensite. The fine-grained state produced by rotary swaging and reversion annealing showed a significantly higher fatigue life of about factor 4 compared to the coarse-grained cast state. Relative to forward impact extrusion, rotary swaging provided a higher fatigue life and fatigue strength .
10.1016-j.tca.2005.02.002	4	transformation; martensite; martensitic; phase; shape; beta; memory; shape memory; temperature; temperatures; martensitic transformation; gamma; transformation temperatures; effect; thermal	The effects of neutron irradiation on oxidation behavior, microstructure and transformation temperatures of CuAlNiMn shape memory alloy have been investigated. It is seen that irradiation leads to observable changes of structure, and decreased temperatures of the martensite <-> austenite phase transformation. Oxidation followed an Arrhenius relationship. An increase in activation energy of the oxidation reaction is observed due to applied irradiation.
10.1016-j.tca.2009.11.016	4	transformation; martensite; martensitic; phase; shape; beta; memory; shape memory; temperature; temperatures; martensitic transformation; gamma; transformation temperatures; effect; thermal	Using especially designed and constructed isothermal calorimeter, the austempering of Cu-Ni ductile iron was carried out at temperatures of T-pi =270,350,390 and 430 degrees C, simultaneously with the measurement of accompanying thermal effects. The values of enthalpy changes Delta H show the correct and expected trend, varying from 45 J/g at T-pi =430 degrees C to 70 J/g at T-pi = 270 degrees C. The changes of enthalpy were observed to increase with decreasing temperature of the isothermal transformation during austempering. The results of the present work did not allow revealing the influence of alloying elements, i.e. Cu and Ni, on the heat of isothermal transformation. The discrepancies between the results of the actual measurements and the results quoted in other papers were discussed in terms of DSC measurements.
10.1016-j.tca.2012.02.007	4	transformation; martensite; martensitic; phase; shape; beta; memory; shape memory; temperature; temperatures; martensitic transformation; gamma; transformation temperatures; effect; thermal	The effects of thermal aging at a constant temperature above A(f) (austenite phase finish temperature) on the martensitic transformation of the CuAlNi shape memory alloy were investigated. The evolution of the transformation temperatures was studied by differential scanning calorimetry (DSC). It was found that the thermal aging at a constant temperature above A(f) has a complex effect on the transformation parameters of the CuAlNi shape memory alloy. The M-s, M-f, A(s), and A(f) transformation temperatures were shifted by the thermal annealing. The thermodynamic parameters such as Gibbs free energy and the elastic strain energy of the alloy experienced a decreasing tendency with increasing the aging time. The structural properties of aged alloy samples were studied by X-ray diffraction measurements at room temperature. It was found that the phase transformation parameters of the alloy are controlled by the crystallite size effect.
10.1016-j.tca.2012.11.012	-1		In this paper, bulk metallic glasses with the compositions of Cu55-zZr37Ti8Inz (z = 1,3 and 5 at%) have been evaluated from the viewpoint of thermodynamics and kinetics. The activation energies corresponding to the characteristic temperatures have been calculated and the results show that the as-cast alloys have a good stability in thermodynamics. The difficulty of each crystallization step was discussed with activation energy. Furthermore, crystallization mechanism of each as-cast alloy was studied by phase transformation and local Avrami exponent. Depending on the fragility index, Cu54Zr37Ti8In1 can be classified to strong glasses and Cu52Zr37Ti8In3 and Cu50Zr37Ti8In5 should be considered as intermediate glasses. In addition, glass-forming ability of each alloy was discussed thoroughly. The results demonstrate that glass-forming ability increases with content of In element.
10.1016-j.tca.2013.08.012	12	thermodynamic; ternary; phase; data; experimental; equilibria; phase equilibria; liquid; binary; experimental data; calculated; phases; literature; model; calphad	Phase relations of Cu-Ni-Ti ternary system have been experimentally investigated and thermodynamically assessed. Firstly, part of phase relations in the Cu-Ni-Ti ternary system at 800 degrees C was established by analyzing Ti/Cu-Ni diffusion couple and alloy samples with EPMA (Electronic Probe Micro-Analysis). The Cu4Ti3+CuTi+NiTi equilibrium reported in literature was presently modified to a three-phase equilibrium CuTi+NiTi+tau(1) in the 730-830 degrees C temperature range. Based on the measured phase equilibria and those experimental investigations about Cu-Ni-Ti system and in combination to the three binary boundary systems optimized in literatures, thermodynamic parameters of various phases in this system were reasonably modeled through CALPHAD (CALculation of PHAse Diagram) approach . Crown Copyright
10.1016-j.tca.2015.03.024	4	transformation; martensite; martensitic; phase; shape; beta; memory; shape memory; temperature; temperatures; martensitic transformation; gamma; transformation temperatures; effect; thermal	Shape memory alloys (SMA) usually exhibit shifts in the transformation temperatures with increasing the number of thermal cycles. These shifts result from an increased stability of the martensite during cycling and have an important role in the functionality of the material. The structural reasons for these changes are not fully understood and are investigated here by a thermodynamic approach . The variation in the transformation temperatures and in the chemical and non-chemical energy terms of the total energy involved in the transformation of a Cu-Al-Ni-Mn SMA was studied. Powder of this alloy was produced by gas atomization with size in the range of 32-45 mu m and subsequently heat-treated at 180 degrees C, 250 degrees C and 300 degrees C during different times. The as-cast and heat-treated samples were investigated by differential scanning calorimetry, X-ray diffraction and scanning and transmission electron microscopy. Only a single martensitic beta' phase was formed at room temperature. It was observed an increase in the austenitic start transformation temperature (A(s)) as well as in the austenitic finish transformation temperature (A(f)) with increasing the annealing time and temperature. The shift in the transformation temperatures to higher values is attributed to a decrease of the latent heat of transformation and non-chemical energy term, caused by changes in the structural order of the martensite. This study shows that the variation of the transformation temperatures is strongly linked to the total energy components, which can give important information about the stability of the alloy.
10.1016-j.tca.2016.08.001	11	glass; bulk; metallic; bulk metallic; gfa; bmg; glassy; metallic glass; ability; bulk metallic glass; amorphous; addition; crystallization; mm; glass-forming	Bulk metallic glasses with the composition of Cu(43)Zr(48)A(19) and (Cu(43)Zr(48)A(19))(98)Y-2 were prepared by copper mold casting technique in this paper. X-ray diffraction (XRD) and differential scanning calorimetry (DSC) were used to investigate their structure and non-isothermal crystallization kinetics. The results show that the influence of heating rate on crystallization is larger than that on glass transition. The crystallization process of (Cu(43)Zr(48)A(19))(98)Y-2 is more sensitive to heating rate than that of Cu(43)Zr(48)A(19). Due to Yttrium addition, the glass transition and nucleation process for crystallization become easier, while the grain growth process for crystallization become more difficult based on the activation energies. The Avrami exponents of (Cu(43)Zr(48)A(19))(98)Y-2 decrease at low heating rates, which is totally different from that of Cu(43)Zr(48)A(19). These two bulk metallic glasses should be considered as Intermediately fragile glass formers according to their fragility indices. (C) 2016 Published by Elsevier B.V.
10.1016-j.tca.2020.178550	-1		The kinetics of Cr clustering process in a commercial Cu-1Cr-0.1 Zr (wt%) alloy processed by equal channel angular pressing (ECAP) via route BC at room temperature for 1, 8 and 16 passes, has been investigated using Differential Scanning Calorimetry (DSC). The DSC scan results showed that the Cr clustering peak temperature reaction increases with increasing the heating rate and decreased with the imposed strain. The activation energy of clustering was estimated using Kissinger, Boswell and Ligero analytical methods. The obtained values were in the range of similar to 137 and 144 kJ/mol. The Avrami parameter n was around unity which corresponds to a process of grain boundary nucleation after site saturation.
10.1016-j.tca.2020.178760	4	transformation; martensite; martensitic; phase; shape; beta; memory; shape memory; temperature; temperatures; martensitic transformation; gamma; transformation temperatures; effect; thermal	Effects of aging on the microstructure, structural properties, phase components, transformation characteristics and shape memory behavior of the Cu-12Al-3Mn-0.7Ti-0.3C (wt%) SMA have been investigated by means of SEM, XRD, DSC measurements and the bending test. The results indicate that properties of the alloy depends strongly on aging temperatures performed at 300 degrees C, 400 degrees C and 500 degrees C for 30 minutes. While the alloy sample aged at 300 degrees C has generally similar properties with the base alloy sample, as the aging temperature increases, significant changes have occurred in the microstructural properties of the alloy. After aging at 500 degrees C, alpha-phase precipitated as a result of beta phase decomposition and micro voids formed in the microstructure of the alloy. It is found that these obstacles give rise to the expansion of the transformation hysteresis value of 289.3 degrees C for the sample aged at 500 degrees C by affecting transformation temperatures, the change of the thermodynamic parameters and also a decrease in shape recovery ratio of 50% of the alloy.
10.1016-j.tca.2020.178762	-1		Structural relaxation, beta relaxation and crystallization processes of the Cu53Y42Al5 metallic glass were studied in the present work. X-ray diffractometry was used to study the structure of the samples. Phase transformations were studied by differential scanning calorimetry by using a power compensated type differential calorimeter. Cu-mould casting resulted in the formation of crystalline samples while fully glassy Cu(53)Y(42)Al(5 )alloy samples were produced by melt spinning at a high cooling rate of about 10(5)-10(6) K/s. This glassy alloy is characterized by strong beta relaxation and low activation energy values for crystallization and relaxation in comparison with other metallic glasses studied earlier.
10.1016-j.tca.2021.179107	4	transformation; martensite; martensitic; phase; shape; beta; memory; shape memory; temperature; temperatures; martensitic transformation; gamma; transformation temperatures; effect; thermal	Forward and reverse transformation temperatures of shape memory alloys are significantly affected by their thermal and processing history. Controlling these temperatures is of great importance when designing materials displaying shape memory effect. In this direction, the present work shows the influence of particle size and heat treatments on thermodynamic properties of a gas-atomized Cu-Al-Ni-Mn shape memory alloy. Commercially pure elements were used in the gas atomization process and differential scanning calorimetry was used to measure As, Af (austenitic start and final transformation temperatures), Ms, Mf (martensitic start and final transformation temperatures), transformation temperature hysteresis and chemical/non-chemical energies involved in the martensitic-austenitic transformation. The influence of quenched-in defects and annealing was also studied. Results show a correlation between particle size and transformation energies, which can be attributed to atomic ordering in the austenitic phase upon cooling, after the solidification process. This is further confirmed by the increase in the reverse and forward transformation temperatures after thermal cycling and annealing.
10.1016-j.tca.2022.179214	4	transformation; martensite; martensitic; phase; shape; beta; memory; shape memory; temperature; temperatures; martensitic transformation; gamma; transformation temperatures; effect; thermal	In as-quenched CuAlMn-based alloys, the bainitic precipitation can occur between 450 and 625 K on heating. This reaction can promote diffusion into the martensitic phase and can damage the shape memory effect. In this study, the effect of the fourth alloying element (Ag, Ga, and Gd) on bainitic precipitation kinetics in the Cu74.5Al15.0Mn10.5 alloy was evaluated using differential scanning calorimetry, optical microscopy, X-ray diffraction, and the non-isothermal isoconversional method. The study of the Gd addition to the Cu(74.5)Al(15.0)Mn(10.5 )alloy indicated that the Cu5Gd phase increased the number of nucleation sites, thereby reducing the average isoconversional activation energy for the bainitic reaction. Nonetheless, the Ag and Ga additions promoted a more effective change in the kinetic mechanism of the bainitic precipitation. The Ga addition reduced the isoconversional activation energy value and induced the bainitic phase formation at lower temperatures, but it also introduced parallel reactions that turned their lateral growing slower. On another hand, Ag elevated the initial isoconversional activation energy value and shifted up the bainitic precipitation starting, but the presence of Ag precipitates induced the bainite formation in a narrower temperature range. Therefore, the additions of Ag, Ga, and Gd to the Cu74.5Al15.0Mn10.5 alloy changed bainitic precipitation kinetics, which can be associated with modifications in the Cu diffusion energy and the number of nucleation points.
10.1016-j.triboint.2012.06.007	16	wear; composite; composites; powders; milling; particles; powder; wt; sliding; friction; hardness; matrix; mechanical; surface; properties	Tribological behaviors of Cu-6Sn-6Zn-3Pb alloy sliding against AISI321 stainless steel under sea water, distilled water and dry sliding conditions are studied on a pin-on-disc tester. Generally, the friction coefficient in distilled water is the largest and the smallest in dry-sliding. However, the wear rate is in the opposite case. The wear mechanism is microplough and plastic deformation in distilled water and under dry-sliding, but much severe in the latter case. In sea water environment, the wear mechanism is microplough, plastic deformation and corrosion. Sea water and distilled water show a cooling effect in comparison with dry sliding, additionally, sea water also has lubricating and corrosive effects.
10.1016-j.triboint.2015.08.004	-1		Cu-10Ni-3Al-0.8Si alloy exhibited desirable physical and mechanical properties and wear resistance for bearing applications. An electrical conductivity of 18.1% IACS, hardness of 309.3 HV, tensile strength of 1004.2 MPa, coefficient of friction of 0.58 and volume wear rate of 4.69 X 10(-6) mm(3)/mm were obtained with over-aged sample. Adhesion and oxidation were observed to be the two main mechanisms under dry wear condition. The wear resistance of the experimental alloy increased with aging time until the over-aging stage due to the increment of micro-hardness. Adhesion was observed to be the dominant wear mechanism for the cold-rolled sample while tribo-oxidation dominated for the over-aged sample. The latter was attributed to the effect of precipitates on the mechanically mixed layer of the wear sample.
10.1016-j.triboint.2017.12.023	16	wear; composite; composites; powders; milling; particles; powder; wt; sliding; friction; hardness; matrix; mechanical; surface; properties	In the present study, solid-lubricating surfaces were produced through electrical discharge process using green compact electrodes prepared from tungsten disulphide (WS2) and copper (Cu) powder mixture. The effect of experimental parameters such as duty factor, peak current, and powder mixture ratio was investigated on wear behavior and surface integrity of coating. The FESEM images indicated fewer pores with powder mixture ratio WS2:Cu/60:40, peak current 7A and duty factor 50%. The XRD profile of coating showed the various peaks of W, WS2, Cu and Cu2S. Micro-hardness of the solid-lubricating coating reduced from 180HV (workpiece) to a minimum value of 44.11HV (coating). Further, Pin-On-Disc wear test showed significant reduction in wear from 95.75 mu m (parent surface) to the least value of 6.71 mu m (coated surface).
10.1016-j.triboint.2018.05.040	-1		Nano-composite coatings with nano particles contents from 1 to 7 gr/lit, with the electroless bath pHs of 4.5, 7, 9; and electroless bath rotating speeds of 200, 400 and 600 rpm were produced. Microstructural/elemental analyses were performed by various techniques. Electrochemical impedance spectroscopy (EIS) and potentio-dynamic polarization techniques were used to study corrosion behavior. Wear resistance of the coatings was assessed by ball on disk wear test. Results showed that wear resistance of the coatings was improved at higher concentration of particles and by increasing the pH of the electroless bath as well. These conditions reduced corrosion resistance of the coatings, increased phases such as Cu2P7, CuP2, and reduced the P content in the Cu nano-composite coatings.
10.1016-j.triboint.2018.11.027	16	wear; composite; composites; powders; milling; particles; powder; wt; sliding; friction; hardness; matrix; mechanical; surface; properties	Mapping friction and wear behaviours as a function of material composition and operating conditions is a valuable tool, assisting in material selection for component design. The friction and wear maps of copper matrix composites (Cu-MMCs) with different Fe content, tribo-evaluated with different braking energy density (BED) against a steel counterpart, were constructed in this study. According to the friction and wear maps, as well as the wear mechanism map established, Cu-MMCs containing iron volume content ranged from 10% to 15%, exhibited stable high coefficient of friction, associated with low wear rates. Wear mechanisms of Cu-MMCs were distinguished in different regions, which were adhesion, plough, oxidation delamination, severe plastic deformation and delamination.
10.1016-j.triboint.2019.03.055	16	wear; composite; composites; powders; milling; particles; powder; wt; sliding; friction; hardness; matrix; mechanical; surface; properties	The present work explores the effect of aluminium (Al: 0, 3, 5, 10 & 15 wt%) addition on wear behaviour of copper (Cu). The Cu-Al alloys were fabricated via mechanical alloying and high-pressure hot press. In fact, highpressure processes are beneficial as they result in obtaining fine microstructure and property enhancement. Depending on the amount of Al, the microstructure of hot pressed samples (Cu with Al up to 5 wt%) consisted of copper-rich solid solution phase (Cu0.92Al0.08) and the presence of both Cu0.79Al0.22 and Cu9Al4 intermetallic phases for Cu containing high amount of Al ( >= 10 wt%). The relative density of Cu-Al alloys varied between similar to 95 and 98% and the hardness of Cu enhanced significantly from 1.32 to 6.16 GPa with Al content. The coefficient of friction (COF) (0.54 to 0.16) and wear rate (18.26 x 10(-5) to 0.92 x 10(-5) mm(3)/N-m) of Cu decreased with the addition of Al. A transition in wear mechanisms of Cu was observed with Al. In case of pure copper, adhesion was the major wear mechanism. Adhesion and tribo-oxidation controlled the wear of Cu alloyed with Al (up to 5 wt%). Oxide layer formation influenced the wear of Cu-10Al, while abrasion was the predominant wear mechanism for Cu-15Al. These results clearly indicate the advantage of large amount of Al addition to achieve better wear resistance of Cu.
10.1016-j.triboint.2019.04.006	17	wear; composites; coating; friction; composite; coatings; surface; tribological; properties; wear resistance; resistance; powder; sliding; matrix; wear rate	This study investigated the tribological properties of Cu36Zr48Ag8Al8 BMG against Cu36Zr48Ag8Al8 BMG under H2SO4 corrosive conditions with different concentrations. Results show that Cu36Zr48Ag8Al8 BMG exhibits good tribological behaviors under H2SO4 conditions. Especially, when the material was soaked in 15 wt% H2SO4 solution, the friction coefficient and wear rate can be as low as 0.10 +/- 0.01 and (0.28 +/- 0.23) x 10(-6) mm(3)N(-1) m(-1). It is mainly attributed to the existence of metal oxide films formed by surface oxidation and passivation actions as well as the fluid lubricating films formed by H2SO4 solution and dissolution reaction products (Al-2(SO4)(3) and CuSO4) on the worn surfaces. These perfect properties promote Cu36Zr48Ag8Al8 BMG to have the promise to replace the stainless steel under H2SO4 corrosive condition.
10.1016-j.triboint.2019.105843	-1		In this work a textured diamond-reinforced copper-beryllium composite was produced and its tribological behavior was evaluated. In a first stage, a Cu-Be matrix was textured by laser and diamond particles were functionalized with a Cu-Sn-Ti eutectic alloy by mechanical alloying. The second stage consisted on the incorporation and consolidation of the functionalized diamond particles to the matrix by laser sintering. The results showed that despite some heterogeneity of the powders/matrix interface, the textured diamond-reinforced copper-beryllium materials exhibited a much better tribological performance than the unreinforced Cu-Be ones. Such behavior was attributed to the presence of diamond and formation of oxides, like TiO2, that act as solid lubricant. No graphitization was observed during laser sintering process.
10.1016-j.triboint.2019.106121	17	wear; composites; coating; friction; composite; coatings; surface; tribological; properties; wear resistance; resistance; powder; sliding; matrix; wear rate	Tribological and frictional noise properties of TC4 with different sizes of surface dimples filled with Sn-Ag-Cu (SAC) and TiC are investigated using friction and noise experimental apparatus. The results show that TC4 with surface dimples of 0.6 mm diameter (TSC-0.6) has the best tribological property and frictional noise suppression capability. It is attributed to the synergistic effect of SAC and TiC, which can be easily extruded to the worn surface to form a complete lubricating layer. Meanwhile, the roughness of the worn surface is decreased. This investigation is of great significance in improving the tribological property of TC4 and suppressing the frictional noise for its wider application in aerospace and automotive fields.
10.1016-j.triboint.2021.107156	-1		Copper (Cu) is almost an essential constituent of friction materials (FMs) since it shows multi-functionality in performance. However, it is being banned due to its adverse effects on aquatic life. In the present research work, iron-aluminum (FA25) alloy particles were explored for Cu replacement. With the help of fixed parent composition, five types of brake-pads were manufactured with variations in FA25 alloy content as 0, 5, 10, 15, and 20 wt%. One more kind of pad was developed containing Cu in 10 wt% for the sake of comparison. The brake-pads were characterized for physical, mechanical, thermal, tribological properties and noise-vibration (NV) performance. The 10 wt% alloy proved to be the optimum amount to replace the Cu with superior performance if fade resistance and counterface friendliness can be compromised slightly.
10.1016-j.triboint.2022.107435	6	grain; deformation; strain; strength; dislocation; cu-; tensile; size; ecap; grain size; sfe; ductility; hardening; high; stress	The nanotwinned Cu/FeCoCrNi high entropy alloy crystalline/crystalline nanolaminates (NT Cu/HEA C/CNLs) are studied extensively due to their high strength and great plasticity, but their tribological property is still a mystery. Here, the tribological property and subsurface damage of NT Cu/HEA C/CNLs at various scratching parameters are investigated via atomic simulation. The friction coefficient, wear loss, wear rate, subsurface damage, and dislocation behavior are analyzed. A strong dependence of tribological property and subsurface damage on scratching velocity and normal load is uncovered. The results provide a prediction for wear and damage during the service of NT Cu/HEA C/CNLs, and contribute to insight into the subsurface damage mechanism. The investigation is essential to ensure the service performance and engineering application.
10.1016-j.triboint.2022.107771	2	corrosion; surface; film; electrochemical; films; spectroscopy; layer; current; solution; potential; resistance; composition; x-ray; ions; showed	This work investigated the cavitation erosion performance of two copper alloys in deionized water (DW) and artificial seawater (ASW) for 10 h . Specifically, scanning electron microscopy observation was performed on the alloys exposed to cavitation erosion for different periods (within 3 h) at the same sites to study the microstructural evolution. The results tested in DW showed that the accumulation of the stress at phase boundaries caused crack generation in the alpha phase and severe deformation of the hard phases (kappa & Fe(Al,Cu)), resulting in the exfoliation of the hard phases. However, the deformation of the hard phase was not observed from the samples tested in ASW due to stress corrosion cracking and material dissolution at the phase boundaries.
10.1016-j.triboint.2022.107941	-1		Herein, in situ MoB particles reinforced Cu-Al matrix composites are prepared by sintering the Cu and MoAlB mixture. During the sintering process, Al atoms can diffuse out of the layered MoAlB and solid-dissolve into the Cu matrix, resulting in the formation of laminate MoB and Cu-Al alloy. The mechanical properties of as-prepared composites are significantly improved because of multiple strengthening mechanisms. Moreover, the two-body abrasive and adhesive wear effects are inhibited on account of the pinning effect of MoB particles. With the MoAlB content increasing up to 20 wt% and 30 wt%, a layer of tribo-film can be generated due to the tribo-oxidation reaction during the sliding, which can provide lubrication to reduce friction and wear.
10.1016-j.triboint.2022.108193	17	wear; composites; coating; friction; composite; coatings; surface; tribological; properties; wear resistance; resistance; powder; sliding; matrix; wear rate	High temperature copper matrix self-lubricating composites are essential for industrial applications. This paper fabricated the Cu-Ni-Al/Gr solid-lubricating composites with 2.5-10 wt% graphite. Effects of graphite contents on the tribological behavior at room temperature to 500 degrees C were thoroughly studied. The conclusions present that the addition of graphite significantly improves tribological properties while no further enhancement can be made when graphite reaches 7.5-10 wt%, which shows the friction coefficient of 0.04-0.22 and wear rate of (1.02-10.12)x 10-5 mm3/Nm. The excellent tribological performance at 25-500 degrees C is attributed to the syner-gistic effects of the self-lubricating property provided by graphite lubricant and the tribo-oxide layer formed during the sliding process.
10.1016-j.triboint.2023.108392	-1		Rapid hot-press sintering was employed to prepare the self-lubricating composites using Cu-Sn alloy, Cu-coated graphite, and Cu-coated MoS2 powder as raw materials. The effects of the sintering temperature on the microstructure, interfacial characteristics, and friction properties of the composites were primarily examined. The findings demonstrated that as the sintering temperature rose from 680 degrees C to 780 degrees C, the copper alloy matrix's grain size grew. The composites' density and hardness increased and subsequently declined as the sintering temperature rose. Moreover, the interfacial bonding between the copper-coating lubricant and the copper alloy matrix was improved by raising the sintering temperature. The average friction coefficient of the composite grew and then fell as the sintering temperature rose, and the wear initially increased, then decreased, and then increased again. The copper-tin composite had good frictional properties because a composite lubricating film made of graphite, MoS2, and metal oxides formed on the worn surface. Among them, the comprehensive friction performance was best at the sintering temperature of 760 degrees C, with an average friction coefficient of 0.11 and a wear rate of 2.332 x 10 6 mm(3)N(-1)center dot m(-1). The wear mechanism was the combined coupling effect of abrasive wear, adhesive wear and oxidative wear.
10.1016-j.triboint.2023.108724	-1		Introduction of hard particles into the soft copper is an effective method to strengthen copper and improve its wear resistance, while it normally sacrifices the electrical conductivity. The type and content of the addition phase have great influence on the electrical conductivity and wear resistance trade off. Herein, we introduced self-lubricating and conductive Ti3SiC2 particles into the soft copper, and self-lubricating Ti3SiC2/Cu composites were fabricated by vacuum hot pressing sintering technique. It was found that dense composites with homogeneous Ti3SiC2 distribution was obtained when addition content of Ti3SiC2 was relatively low, less than 20 vol% Ti3SiC2 additions, while the composite became porous after larger content, especially over 40 vol%. Introduction of Ti3SiC2 significantly enhanced the wear resistance without obviously sacrificing of electrical conductivity. The composites with 20 vol% Ti3SiC2 content had the lowest wear rate of 3.135 x 10-5 mm3 N-1 m-1 with conductive 63% IACS. Self-lubricating film was detected on the friction surface, which sharply reduced the composite's wear rates. At the same time, hardness of the composite was obviously increased by 98% compared with copper, up to 121 HV, which was beneficial to the improvement of wear resistance. Introduction of Ti3SiC2 has been demonstrated to obviously strengthen copper with electrical conductivity and wear resistance trade off.
10.1016-j.triboint.2023.108863	-1		The superior fretting performance of polymer-bonded MoS2-based dry film lubricant (DFL) coating on a plasmasprayed Cu-Ni-In under-layer is well known. The Cu-Ni-In under-layer changes both the material and the topography of the surface onto which the DFL is applied. However, the mechanism of how the DFL/Cu-Ni-In interface improves fretting performance requires further investigation. Here, the effects of material and roughness were isolated by using surfaces with the Cu-Ni-In under-layer coating and the TI-6Al-4 V substrate in both the ground and grit-blasted conditions. Increasing Cu-Ni-In surface roughness from 1 & mu;m to 9 & mu;m more than doubled fretting lifetime. The Cu-Ni-In under-layer is shown to provide added durability and extended lifetimes, over fivefold, when compared to Ti-6Al-4 V substrate despite having similar surface topographies.
10.1016-j.triboint.2023.108884	16	wear; composite; composites; powders; milling; particles; powder; wt; sliding; friction; hardness; matrix; mechanical; surface; properties	This research study presents the effect of CaF2 reinforcement on the microstructure, mechanical and selflubricating (SL) tribological properties of Cu-Ni alloy/cBN metal matrix composite (MMC). The composite of Cu-Ni (CN) alloy/cBN reinforced with CaF2 nanoparticles (2-6 wt%) was developed by powder metallurgy, using pressure-less sintering without any additive. Microstructure studies proved uniform dispersion of cBN/ CaF2 particles in the Cu-Ni matrix. The maximum density and hardness were obtained at reinforcement of 2 wt% CaF2. The minimum coefficient of friction (0.15) and higher wear resistance were obtained for 4 wt% CaF2 reinforcement in CN alloy/cBN composite. Tribo-chemical reactions culminated in the formation of oxides of Cu, Ni, Fe and B at the interface, which significantly influenced the tribological properties and wear mechanisms. The worn surface analysis indicated that adhesive wear, oxidative wear and delamination are the predominated wear mechanism of CN alloy-cBN-CaF2 composite.
10.1016-j.triboint.2023.108909	17	wear; composites; coating; friction; composite; coatings; surface; tribological; properties; wear resistance; resistance; powder; sliding; matrix; wear rate	This article investigates the effect of nickel-induced finite plastic deformation at the friction interface of the CuSn10Bi3 bimetallic copper layer on its tribological properties. CuSn10Bi3 alloy bimetallic samples with different nickel contents were prepared by powder metallurgy, and the microstructure and Brinell hardness were observed. The tribological performances and wear behaviors under dry friction and oil-depleted lubrication conditions were evaluated and analyzed. The results show that the Ni in the copper-tin-based alloy reduces the surface porosity of the powder metallurgical samples. With the increase of Ni content from 0.5 wt% to 1.2 wt% and 2 wt%, the porosity decreased by 36%, 48.7% and 62.3%, respectively, and the hardness of the samples increased slightly. The grain size of the alloy decreases with the increased Ni content, which is attributed to the increase of twinning. Besides, the friction coefficient of Ni-containing samples was more stable and the wear under dry friction was significantly reduced, especially, the wear loss is reduced by 78.2% when the content of Ni is 2%. The wear mechanism changed from abrasive-dominated and oxidative wear to plastic deformation dominated and furrow wear. The limited plastic deformation of the friction interface caused by the addition of 2% nickel is a new strategy for solving the problem of brittle exfoliation of wear surfaces and improving the wear resistance of Bi-containing copper alloys.
10.1016-j.triboint.2023.109117	16	wear; composite; composites; powders; milling; particles; powder; wt; sliding; friction; hardness; matrix; mechanical; surface; properties	In the present work, the nanowear test is carried out at 5500 mu N load with a large pitch distance of 20 mu m and 3500 mu N load with a low pitch distance of 3 mu m on Laser Powder Bed Fusion (LPBF) produced CuCrZr alloy. The volume of material removal and normal wear depth at a low pitch value were studied. Further, the deformation of nano twins along the sliding direction was discussed. Coefficient of friction and depth of wear track at a low pitch value were studied. In addition to that the ratio of H/Er and H3/Er2 are studied and not suitable to measure the wear resistance of LPBF CuCrZr material at low pitch values.
10.1016-j.triboint.2024.109537	-1		Copper/graphite composites are widely used due to their excellent electrical, thermal, and self-lubricating properties. However, their mechanical and anti-wear properties are usually limited by brittle graphite and soft copper matrix. Enhancing the properties of composites by further introducing harder ceramic particles is an effective way. However, these particles are usually poorly wetted to metal and can easily separate from the matrix during friction, causing more severe abrasive wear. Herein, TiCx-reinforced Cu/graphite composites were prepared by rapid hot press sintering of a hybrid powder consisting of Ti3AlC2, Cu-plated graphite, and Cu powder. Al atoms diffused out of Ti3AlC2 and solid-solved into the Cu matrix during the sintering process, forming TiCx and Cu(Al) alloys. Such in situ formed TiCx particles have good interfacial bonding with the matrix. With the increase of Ti3AlC2 addition from 0 to 15 wt%, the average grain size of the composites decreased, the relative density increased, the hardness became larger, the electrical conductivity decreased, and the average coefficient of friction were all maintained at about 0.14, but the wear rate was reduced from 3.6569 x 10-4 mm3 & sdot;N-1 & sdot;m- 1 to 9.35013 x 10-6 mm3 & sdot;N-1 & sdot;m- 1. The in situ Ti3AlC2-derived TiCx particles improved the deformation resistance and shear resistance of the Cu/graphite composites, thus contributing to the wear resistance. This research may offer fresh perspectives on how to enhance the properties of copper/graphite composites.
10.1016-j.triboint.2024.109645	17	wear; composites; coating; friction; composite; coatings; surface; tribological; properties; wear resistance; resistance; powder; sliding; matrix; wear rate	The high-hardness wear-resistant Cu-Ni-Al-Sn coatings were fabricated by laser cladding, and the effect of Sn content on the microstructure, hardness and high temperature tribological behaviors of the coatings was investigated. The results revealed that the hardness of the coatings increased from 177.6 to 674.0 HV0.3 due to the strengthening of Cu9NiSn3, FeNi and NiSn precipitations. In addition, Sn plays an important role in improving the high temperature tribological properties of the coatings. At 25-200 degrees C, Sn can form a low shear-stress film to reduce the friction coefficient and wear rate. When the temperature exceeds 300 degrees C, a tribo-oxides layer containing SnO2, CuO and Fe2O3 forms on worn surfaces, which play a role in improving the tribological properties.
10.1016-j.triboint.2024.109967	-1		Constitution and distribution of phases and interphase reactions are crucial for properties of composites. So far, the problem of MoS2 agglomeration remains unsolved in Cu/MoS2 composites, and interfacial structures and reaction products between MoS2 and Cu have not been fully considered. Herein, Cu-coated MoS2 powders prepared via electroless plating were sintered at different temperatures into Cu/MoS2 composites. Cu does not react with MoS2 in the composites sintered at 600 degrees C and 650 degrees C, leading to their desirable tribological properties under dry sliding. Reactions between Cu and MoS2 occur in the composites sintered at 700 degrees C and 800 degrees C, and the resultant products include Cu2S, Cu1.8Mo6S8 and Cu1.83Mo3S4 phases, resulting in a better wear resistance under oil lubrication and mechanical properties.
10.1016-j.triboint.2024.110011	-1		In this study, hybrid composites were generated by combining Copper (Cu) powder with Chromium (Cr) powder at a fixed weight of 1 %, as well as Boron (B) and Boron carbide (B4C) powders at specific weight ratios (1 %, 2 %, 3 %, and 4 %), with variable particle sizes (1 mu m and 44 mu m). Powder metallurgy production parameters were employed to produce two sets of samples at sintering temperatures of 750 degrees C and 850 degrees C. Analysis of the microstructure of the samples was performed, as well as hardness and abrasion tests. A variety of B/B4C ratios and particle diameters were employed to characterize Cu-based hybrid composites using SEM-EDS and XRD. Weight loss graphs and coefficient of friction values were generated for each sample subsequent to wear tests. The results of the tests indicated a 76.25 % increase in hardness values with B reinforcement and a 60.71 % increase with B4C reinforcement in comparison to a pure Cu sample. As the sintering temperature increased and the size of the reinforcement particles decreased, the hardness of the material increased, resulting in identical results in the wear testing. A tribo-layer was observed to have formed between the wear pin and the samples in the new hybrid composites with Boron matrix in the SEM images taken after wear. The wear resistance properties of Cu matrix hybrid composites were found to be enhanced by this tribolayer.
10.1016-j.triboint.2024.110090	-1		Gallium-based liquid metal (GLM) is an emerging lubricant because of low melting point, good fluidity and thermal stability, high thermal conductivity and electrical conductivity. This work investigates the tribological behavior of GLM for Cu/Al tribo-pair. It is found that with GLM lubrication, the friction coefficient of the Cu/Al tribo-pair is reduced by approximately 1.5 to 3 times, and the wear rate of the Cu alloy is also reduced by about 4 to 16 times, compared to dry friction. Furthermore, under high-speed and high-load conditions, the lubrication effect of GLM for the Cu/Al tribo-pair is particularly prominent. GLM provided fluid lubrication for the Cu/Al tribo-pair, and the formation of a gallium-aluminum metal film on the worn surface effectively prevents the direct contact of tribo-pair, thereby reducing friction and wear.
10.1016-j.triboint.2024.110096	-1		This work used laser powder bed fusion (LPBF) to successfully produce in-situ nanoscale amorphous oxide dispersion strengthened (AODS) immiscible Cu-316 L bimetallic composite. Due to high affinity of Cr and O and the high cooling rate of LPBF, the formation of in-situ nano-amorphous Cr-rich oxide particles can refine the gamma-Fe particles embedded in epsilon-Cu matrix. Moreover, the gamma-Fe particles have shadow protection effect on epsilon-Cu matrix, the wear mechanism is mechanical wear during low current-carrying wear (0-2 A). However, during high current-carrying wear (5 A and 7 A), arc erosion preferentially occurs on gamma-Fe particles with lower work functions, which enhances arc erosion resistance of epsilon-Cu matrix. The wear mechanisms are dominated by electric-arc erosion and oxidation wear.
10.1016-j.triboint.2024.110107	17	wear; composites; coating; friction; composite; coatings; surface; tribological; properties; wear resistance; resistance; powder; sliding; matrix; wear rate	Copper alloy-molybdenum coatings were prepared on the surface of Cu-Cr-Zr alloys by laser cladding. The phase and microstructure were observed, and the hardness, conductivity, friction and wear properties under currentcarrying conditions were tested. The results indicate that the prepared coatings exhibit good metallurgical bonding with the substrate. The Brinell hardness of the coatings ranges from 60 to 105 HB, and the electrical conductivity ranges from 17 % to 27 % IACS. The primary wear mechanism is abrasive wear and adhesive wear without current, resulting in the detachment of the Mo phase and transfer of the Cu phase during the sliding process. And it shifts to severe adhesive wear under current-carrying conditions, leading to the formation of aluminum deposit on the coatings.
10.1016-j.triboint.2024.110452	14	strength; properties; conductivity; electrical; mechanical; cu-; grain; mpa; electrical conductivity; aging; precipitation; phase; mechanical properties; tensile; phases	Copper-based graphite composite coatings with preferable high-temperature tribological properties were prepared using laser cladding. The study comprehensively examined the effects of graphite content on the microstructure, hardness and tribological properties across a temperature range of RT to 500 degrees C. The results indicate a significant increase in hardness of the coatings, ranging from 178.9 to 737.1 HV0.2. This enhancement primarily stems from solid solution and in-situ Fe3C. As the graphite content increases, the friction coefficient of the coatings decreases, while the wear rate initially decreases and then increases. The primarily wear mechanism shifts from abrasive wear at RT-300 degrees C to oxidative wear at 400-500 degrees C. The formation of a tribolayer consisting of graphite and metal oxides improves the high-temperature tribological properties.
10.1016-j.triboint.2025.110848	14	strength; properties; conductivity; electrical; mechanical; cu-; grain; mpa; electrical conductivity; aging; precipitation; phase; mechanical properties; tensile; phases	A comparative study was conducted to evaluate the tribological properties of base alloy (Cu-15Ni-8Sn, wt%) and Si-Ti-modified alloy (Cu-15Ni-8Sn-0.3Si-0.1Ti, wt%). Both alloys were tested against 100Cr6 steel under dry sliding conditions at various loads using a block-on-ring tester. Scanning electron microscopy and transmission electron microscopy revealed that the Si-Ti-modified alloy exhibits a refined grain structure with reduced discontinuous precipitation, significantly enhancing plasticity while improving tribological performance. The addition of trace amounts of Si and Ti stabilizes key sub-tribo-layers (oxide layer and mechanically mixed layer) and promotes a transition from abrasive/adhesive wear to oxidative wear. Consequently, the modified alloy shows lower friction coefficients and specific wear rates compared to the base alloy, demonstrating superior anti-friction and wear-resistance properties under these conditions.
10.1016-j.triboint.2025.110988	-1		In this study, ultrasonic flat rolling process (UFRP) is employed on the electron beam melting manufactured pure copper (EBM-Cu) to construct a gradient structure, evolving from coarse grain to sub-micro laminated, then to equiaxed nano-grain, and finally to amorphous-nanocrystalline structure. Using transmission electron microscopy, the microstructural evolution mechanisms and tribological behavior are explored. The results indicate that the dislocation activities contribute to the grain refinement and the twins are absent in EBM-Cu subjected to UFRP, related to the initial microstructure and presence of voids. The amorphous-nanocrystalline structure, combined with a smooth surface, lead to a remarkable reduction in friction coefficient and wear rate that are respectively 69.12 % and 79.13 % in UR0.2 specimen in comparison with the original EBM-Cu. During wear process, the surface equiaxed nano-grains in UR0.2 specimen continues to transform into new amorphous and Cu2O via dislocation activities, inhibiting cracks initiation and propagation. However, excessive UFRP can cause grain growth via dynamic recrystallization, diminishing the beneficial influence of gradient microstructure. These findings provide a new strategy for regulating microstructure and mechanical properties in additively manufactured components.
10.1016-j.triboint.2025.111159	-1		Cu-4Ti alloy was solution annealed at 900 degrees C for 1 h and water-quenched followed by direct aging (variant I) or aging after 50 % cold rolling (variant II) at 450-600 degrees C for 1-420 min. Microstructure, hardness and wear properties were studied. Variant I yielded uniform beta'-Cu4Ti precipitates, reaching 240 HV after 120 min. at 500 degrees C and narrowing wear tracks to 540 mu m2 with 4 mu m penetration depths. Variant II attained 300 HV in 15 min, yet its dislocation-rich gradient microstructure promoted over-aging, beta-Cu3Ti coarsening and partial recrystallization, expanding grooves beyond 1 mm2 despite higher hardness. ANOVA confirmed temperature as dominant wear driver. Overall, variant I offers best hardness-wear compromise, whereas variant II provides only optimized short aging.
10.1016-j.tsf.2003.10.092	2	corrosion; surface; film; electrochemical; films; spectroscopy; layer; current; solution; potential; resistance; composition; x-ray; ions; showed	Single-phase Cu(In,Ga)(Se,S)(2) alloys have been prepared using a novel two-step selenization/sulfurization growth process to react copper-indium-gallium alloy films. The growth scheme differs critically from standard two-step growth processes and is based on the manipulation of the reaction kinetics in order to inhibit the formation of stable ternary phases. In the first step, the metallic precursors are reacted with H2Se/Ar to produce a composite alloy containing a mixture of binary selenides and at least one partially reacted ternary alloy. The film is then exposed to H2S/Ar at a defined temperature to produce uniform, single-phase pentenary Cu(In.Ga)(Se,S)(2) alloys. Solar cell results for Cu(In,Ga)(Se,S)(2) films with the S/(S + Se) ratio from 0.23 to 0.65 at a fixed Ga/(Ga + In) ratio are presented.
10.1016-j.tsf.2005.10.029	9	magnetic; magnetization; magnetoresistance; temperature; superparamagnetic; annealing; gmr; field; magnetic properties; ferromagnetic; granular; samples; magnetic field; melt-spun; particles	We have studied microstructural, magnetic and electrical transport properties of melt-spun Cu90Co5Fe5 granular alloys. XRD results show the phase formation and the decomposition of the Cu-Co (Fe) solid solution, occurred by the annealing of the samples at a certain temperature. AFM (atomic force microscopy) investigation demonstrates the distribution of particles size and MFM (magnetic force microscopy) directly shows the ferromagnetic granules on the copper matrix. These results are corroborated by the magnetic properties of the samples. Magnetic and electrical transport properties have been studied in the temperature range 15-300 K through ac susceptibility and dc resistivity measurements in the presence of magnetic field. The measured magnetoresistance of the samples reaches the highest value at an optimum annealing temperature.
10.1016-j.tsf.2006.12.055	2	corrosion; surface; film; electrochemical; films; spectroscopy; layer; current; solution; potential; resistance; composition; x-ray; ions; showed	Single-phase Cu(In,Ga)(S,Se)(2) (CIGSS) thin films have been prepared using a two-step process consisting of annealing of Cu-In-Ga precursors in S/Se ambient. Full characterizations have been carried out using XRD, SEM, EDS, Raman spectroscopy and optical absorption measurements. The depth profiles of constituent elements Cu, In, Ga, S and Se were almost constant throughout the film. Depending on overall Ga content and recrystallization temperature CIGSS thin films exhibited a shift in band gap from 1.04 to 1.19 eV.
10.1016-j.tsf.2006.12.145	-1		Cu(In,Ga)S-2 crystals have been grown from the melt using constituent elementary substances as sources. The chalcopyrite structure was confirmed by powder X-ray diffraction patterns. Lattice parameters a and c changed almost linearly corresponding to the composition ratio between In and Ga. The amplitudes of photo-acoustic signals changed greatly near the band gap energies. This phenomenon is due to the changes of the absorption coefficient. Band gap energies, estimated from the photo-acoustic spectra, also showed continuous change with the composition. (C) 2007 Published by Elsevier B.V.
10.1016-j.tsf.2011.01.137	-1		The incorporation of metal impurities M (M = Ti, Fe, or Sn) into CuGaS2 films is investigated experimentally as a function of impurity concentration. Films are synthesized by thermal co-evaporation of the elements onto glass/Mo substrates heated to 400 degrees C-570 degrees C. The compositions of the resulting films are measured by energy-dispersive X-ray spectroscopy and the structures of the present phases are studied by X-ray diffraction. The formation of Cu-M-S ternary phases is observed in a wide range of conditions. Films of Cu-Ga-Ti-S, synthesized at 500 degrees C, show the presence of a cubic modification of CuGaS2 and Cu4TiS4. Alloying of CuGaS2 and tetragonal Cu2SnS3 is observed for substrate temperatures of 450 degrees C. A miscibility gap opens at 500 degrees C and above with separate Sn-rich and Ga-rich phases. Similarly, alloys of CuFeS2 and CuGaS2 are only found in Cu-Ga-Fe-S films synthesized at lower substrate temperature (400 degrees C), whereas at 500 degrees C a miscibility gap opens leading to separate Fe-rich and Ga-rich phases.
10.1016-j.tsf.2014.02.054	2	corrosion; surface; film; electrochemical; films; spectroscopy; layer; current; solution; potential; resistance; composition; x-ray; ions; showed	X-ray photoelectron spectroscopy (XPS) depth-profiling analysis was performed to investigate the chemical composition of the film formed on Cu-Ni (90/10) alloy in seawater and sulphide-polluted seawater in the absence and presence of an inhibitor, 1,2,3-benzotraizole (BTAH). The chemical composition of the film is found to vary at different depths of the film. In seawater environment, the outermost layer is found to consist of CuO, Cu(OH)(2) and Cu2O. After sputtering for 12 min, the major constituent of the film is Cu2O. In seawater polluted with sulphide also the outermost layer is found to consist of CuO, Cu(OH)(2) and Cu2O without any Cu2S or CuS. After 4 min of sputtering only, the peaks due to Cu2S and CuS are detected and the major constituent of the film is still Cu2O. The sulphides of copper are absent after 8 min of sputtering. In the presence of BTAH, the XPS of the film showed peaks due to carbon and nitrogen up to 4 min of sputtering. This result reveals the presence of the [Cu(I)BTA](n) complex on the alloy surface in both seawater and sulphide-polluted seawater. The percentage of Cu2O is found to be much less than that found in the absence of inhibitor. In both the stated environments, in the absence of BTAH, the oxygen concentration is reduced to a small value only after 20 min of sputtering. Whereas, in the presence of BTAH, the concentration of oxygen is reduced to a very small value after sputtering for 12 min. These results infer the protective ability of the BTAH film on Cu-Ni (90/10) alloy in both seawater and sulphide- polluted seawater even after 30 days of immersion.
10.1016-j.tsf.2015.10.081	-1		Thin film metallic glasses (TFMG) can possess a variety of advantages against crystalline thin metal films. High strength and toughness as well as specific corrosion resistivity are features, which can be widely used in MEMS (micro-electromechanical systems), lab-on-a-chip or surface acoustic wave (SAW) device applications. Amongst others, the Cu-Ti binary alloy system is known for having a moderate glass forming ability (GFA) in mid-composition range. In the present study a systematic characterization of sputter deposited Cu-Ti thin films in dependence on the chemical composition is carried out. Intrinsic stress, Young's modulus, surface roughness and electrical resistivity are discussed with respect to the present phases and microstructure. Especially the films within the amorphous range from 25 to 75 at% Cu exhibit favorable mechanical properties. (C) 2015 Published by Elsevier B.V.
10.1016-j.tsf.2016.12.024	2	corrosion; surface; film; electrochemical; films; spectroscopy; layer; current; solution; potential; resistance; composition; x-ray; ions; showed	Bronze disease is a very dangerous cyclic copper corrosion phenomenon which commonly develops after the discovery of the artefact. Therefore, in the cultural heritage field every object is inimitable and whatever loss is irreplaceable, causing a protective coating to be indispensable. Herein we studied the efficiency of a transparent, protective and reversible diamond-like carbon (DLC) coating, deposited by plasma enhanced chemical vapour deposition on copper based alloys, to enhance the corrosion resistance of archaeological artefacts. The nano structured DLC film resulted in the formation of a structure that exhibits water repellent properties and can act as a barrier layer to corrosion. Exposure of copper based alloys, with and without the DLC coating, to an aggressive chemical environment led to a remarkable inhibition of corrosion only for the coated samples. Moreover the DLC film on the Cu-based substrate was shown to have no effect on the morphology of the surfaces indicating that surface appearance is not affected. Consequently DLC coatings open a pathway into the development of safe and tailored solutions in the ancient metals conservation field. Furthermore the use of DLC coatings can be extended for the protection of objects that do not belong to cultural heritage but may still be subject to corrosion.
10.1016-j.tsf.2016.12.048	-1		A binary nanocrystalline Cu67Cr33 thin film alloy consisting of columnar grains was synthesized via co-evaporation of the constituent elements under non-equilibrium ultra-high vacuum conditions using molecular beam epitaxy. In the as-deposited state, the alloy film is a supersaturated solid solution with a single-phase body-centered cubic structure. In order to study the thermal stability of the microstructure and phase separation behavior towards the two phase equilibrium structure, isothermal annealing experiments in a temperature range of 150 degrees C-500 degrees C were conducted inside a transmission electron microscope and compared to data obtained by X-ray diffraction under protective N-2 atmosphere. It is shown that the single-phase nature of the alloy film is maintained for annealing temperatures of <= 300 degrees C, whereas heat treatment at temperatures of >= 400 degrees C results in the formation of a second phase, i.e. the equilibrium face-centered cubic phase of Cu. Phase separation proceeds predominantly by a spinodal-type decomposition process but a simultaneous diffusion of Cr along the columnar grain boundaries to the surface of the alloy film is observed as well. Temperature dependent diffusion coefficients for volume and grain boundary diffusion along with the activation energy for volume diffusion of Cr within the crystal lattice of the alloy film in a temperature range between 400 degrees C-500 degrees C are determined from analytical in situ transmission electron microscopy experiments. Moreover, grain boundary diffusion of Cr leads to the growth of an external Cr-rich oxide scale. It is found that the growth kinetics of this oxide scale exhibits a transition from a linear to a nearly parabolic growth rate.
10.1016-j.tsf.2017.05.042	2	corrosion; surface; film; electrochemical; films; spectroscopy; layer; current; solution; potential; resistance; composition; x-ray; ions; showed	This paper investigates the effect of graphene oxide (GO) on morphology, microstructure and corrosion behaviour of Cu-GO composite coatings. Cu-GO composite coatings were electrodeposited on mild steel substrate by dispersing chemically synthesised GO into a Cu electrolytic bath . Anionic surfactant (sodium lauryl sulphate) was used to obtain uniform and compact coating morphology. Incorporation of GO into Cu matrix produced a finer granular coating morphology with a strong < 220 > preferred orientation. The analysis of electrochemcial corrosion test results revealed that steels coated with Cu-GO were invariably more corrosion resistant compared to both bare steel and pure Cu coated steel. Extent of the reduction in the corrosion rate increased with increasing amount of GO in electrodeposited Cu matrix. Improved corrosion resistance of Cu-GO coatings was related to < 220 > texture and high impermeability of GO to Cu+ ions and dissolved O-2 in the chloride media.
10.1016-j.tsf.2017.10.030	-1		A composition-spread Cu-Zr thin film library with Zr contents from 2.5 up to 6.5 at% was synthesized by magnetron sputtering on a thermally oxidized Si wafer. The compositional and microstructural variations of the Cu-Zr thin film across the composition gradient were examined using energy dispersive X-ray spectroscopy, X-ray diffraction, and high-resolution scanning and transmission electron microscopy of cross-sections fabricated by focused ion beam milling. Composition-dependent hardness and elastic modulus values were obtained by nanoindentation for measurement areas with discrete Zr contents along the composition gradient. Similarly, the electrical resistivity was investigated by 4-point resistivity measurements to study the influence of Zr composition and microstructural changes in the thin film. Both, the mechanical and electrical properties reveal a significant increase in hardness and resistivity with increasing Zr content. The trends of the mechanical and functional properties are discussed with respect to the local microstructure and composition of the thin film library.
10.1016-j.tsf.2018.03.039	-1		Within this work, monolithic Cu-Mo alloy films were grown by d.c. magnetron sputter co-deposition at room temperature and 473 K on Si (100) substrates. The Cu-Mo system was studied within the complete concentration range between pure Cu and pure Mo with steps of similar to 10 at%. Depending on growth conditions and composition, metastable Cu-rich or Mo-rich solid solutions in single-phase films rich in either Cu or Mo, respectively, or dual-phase films consisting of both phases for intermediate compositions are formed. The physical properties in terms of residual stress, hardness, elastic modulus and electrical resistivity are correlated with the chemical composition and the microstructure of the films. The formation of either Cu-rich or Mo-rich solid solutions stabilizes the film structure and stress state, while the dual-phase films exhibit a pronounced self-annealing behavior resulting in residual stress release with time.
10.1016-j.tsf.2018.12.023	2	corrosion; surface; film; electrochemical; films; spectroscopy; layer; current; solution; potential; resistance; composition; x-ray; ions; showed	Electropolished copper foil was passivated in aqueous solution of 1.0 M NaOH at negative potential range vs. silver chloride electrode at room temperature. The passivations were performed at -50, -100, -150, and-200 mV for 1, 5 or 15 h . The resulting nano-needle layers were characterized by X-ray photoelectron spectroscopy and band gaps derived from UV-Vis spectroscopy evidencing coincidence of Cu(OH)(2), CuO and Cu2O phases. Scanning Electron Microscopy revealed that the diameter of nanoneedles was not influenced by the passivation potential, however, the nanoneedles diameter was decreasing with extension of the passivation time (the smallest diameter obtained was 60 +/- 17 nm). Additionally, the as-prepared oxide nano-needles were found to be polycrystalline, without any post treatments. All together, chemical compositionand physical properties (band gap) show that the inner part of the grown nano-needles is rather made of Cu2O, while outer part, there where the passivation reaction takes place, is made of CuO and Cu(OH)(2).
10.1016-j.tsf.2020.138037	-1		A series of Cu-X (X = W, Mo, Nb, Cr, V, Al) films with similar Cu content (about 50 at%) were prepared by dual-target co-deposition technique. By using this method, we found that the multilayered structure can be detected in Cu-W, Cu-Mo, Cu-Nb, Cu-V and Cu-Cr films, but not in Cu-Al films. Except for Cu-Al system, the multilayered structures are made up of Cu-rich and X-rich sublayers rather than conventional pure Cu and X layers. Based on our previous work, we further proved that the confocal targets, rotation of sample stage and the existence of diffusion barrier elements are the essential conditions for obtaining the multilayered structure within the films. The formation mechanism of the multilayered structure by co-deposition was discussed. Initially, the multilayered structure is formed by co-sputtering deposition with the sample stage rotation. And the multilayered structure can remain stable and become more prominent with the uphill diffusion of Cu in immiscible systems. However, in miscible systems, because of the interdiffusion and forming intermetallic compounds between Cu and X (such as Al), the initial multilayered structure can be interrupted and disordered. In addition, the morphology of multilayered structure formation also depends on the diffusion barrier abilities of the elements.
10.1016-j.tsf.2020.138126	-1		Special thermal conductivity bridging is conducted between metal matrix and graphene oxide (GO) with covalent bond (Cu-O-Si-O-C) from gamma-glycidylether propyl trimethylsilane (GPTS) to decrease thermal resistance and weaken phonon scattering through interface. The implementation of this bridging process involves a pulsed electrophoretic deposition, in which the GPTS modified GO as thermal conductivity reinforcing material was deposited onto the Cu-Zn alloy. The composite morphology and interfacial structure by field emission environment scanning electron microscope shows that the GPTS-GO is uniformly deposited on the substrate surface, and there is no interlayer of the GPTS-GO/Cu differing from the GO/Cu without GPTS. Raman spectrum reveals the bonding of Cu-O-Si and Si-O-C to prove the bridging role of GPTS by structural defects of the graphene and the changes of relative characteristic peaks before and after modification, as well as the Fourier transform infrared spectrum results confirming the Cu-O-Si-O-C covalent bonds. Compared to the thermal stability and thermal conductivity by thermogravimetric analyzer from room temperature to a higher temperature of 150 degrees C for the GO/Cu sample without GPTS, the GPTS-GO/Cu exhibits significantly improved performances. The thermal conductivity achieves 415.2 and 361.9 W/mK M 50 degrees C to 150 degrees C, which is 5.01% and 6.00% higher than that of the GO/Cu, The thermal diffusion coefficient achieves 1.236 and 1.087 cm(2)/s M 50 degrees C to 150 degrees C, respectively.
10.1016-j.tsf.2022.139123	-1		The effects of Zr solute content and temperature on the thermal stability and thermal mechanical properties of nanocrystalline (NC)-Cu alloyed with Zr at grain boundaries (GBs) are studied using molecular dynamics simulations. The simulation results show that doping 1% Zr into NC-Cu significantly increases structural stability and prevents grain growth at a high temperature of 1000 K via the effect of GB pinning. The number of dislocations that nucleate and propagate significantly decreases with increasing Zr content. Zr doping elongates the elastic deformation phase. Young's modulus decreases with increasing Zr content (in the range of 2%-6%) and temperature. Doping Zr into NC-Cu enhances mechanical strength and ductility at temperatures of 300-800 K.
10.1016-j.tsf.2025.140688	-1		Sputter-deposited, nanocrystalline Cu-Ag thin films produced across a broad compositional and deposition-parameter space were evaluated to unravel the process-structure-property relationships important for creating hard, conductive electrical contacts and coatings. Combinatorial deposition involving pulsed direct current magnetron sputtering of elemental targets enabled swift examination of nearly the full range of alloy compositions and a relevant portion of deposition atomistics. Several high-throughput characterization modalities were employed to evaluate the chemistry, structure, and properties of the films. The resultant hardness, modulus, film density, crystal texture, and resistivity were analyzed in terms of key deposition characteristics (incident atom kinetic energy and incidence angle) predicted by binary-collision, kinematic Monte Carlo simulations. The study revealed improved hardness, parabolic resistivity dependence on composition, and compositional and process dependencies of film tarnishing. The results are discussed in the context of variations in microstructure and film density. Transmission electron microscopy and X-ray diffraction demonstrate several forms of compositional variation including solute segregation to grain boundaries as well as periodic, intragranular compositional modulations. Annealing of a Cu-rich alloy film exhibiting grain boundary segregation showed that this as-deposited, compositional variation is not stable above 100 degrees C. The Cu-Ag system is shown to have potential for hard, conductive, tarnish-resistant and room temperature-stable nanocrystalline thin films across the composition space.
10.1016-j.tws.2024.112833	-1		Microcomponents are increasingly utilized in electronics, medical, and aerospace applications. Plastic micro- forming is a promising method for fabricating microcomponents due to its low production cost and high productivity. However, at the mesoscale, metal thin sheets exhibit low plastic forming ability due to the size effect, leading to a high propensity for fracture during forming processes. This study investigates the effects of reducing deformation temperature and altering alloy composition on the ductility and forming limits of Cu-Zn thin sheets. A constitutive model for flow stress, based on dislocation evolution and deformation twinning, is developed to cover a wide temperature range from room to cryogenic temperatures (298 to 77 K). The results show that decreasing deformation temperature and increasing Zn content reduce the stacking fault energy, promoting deformation twinning. This enhances strain-hardening capability, inhibits surface roughening, and improves ductility. The developed model predicts the evolution of geometrically necessary dislocations and deformation twins effectively within the room to cryogenic temperature range. Furthermore, integrating the constitutive model and surface roughening with the M-K model improves the accuracy and extends the prediction range of forming limits for Cu-Zn thin sheets. This study provides a theoretical basis for enhancing the formability and reliability of microcomponents in various high-tech applications.
10.1016-j.ultramic.2016.07.011	-1		Metastable Cu-Cr alloy thin films with nominal thickness of 300 nm and composition of Cu67Cr33 (at%) are obtained by co-evaporation using molecular beam epitaxy. The microstructure, chemical phase separation and electronic structure are investigated by transmission electron microscopy (TEM). The thin film adopts the body-centered cubic crystal structure and consists of columnar grains with similar to 50 nm diameter. Aberration-corrected scanning TEM in combination with energy dispersive X-ray spectroscopy confirms compositional fluctuations within the grains. Cu-and Cr-rich domains with composition of Cu83Cr15 (at%) and Cu42Cr58 (at%) and domain size of 1-5 nm are observed. The alignment of the interface between the Cu-and Cr-rich domains shows a preference for {110}-type habit plane. The electronic structure of the Cu-Cr thin films is investigated by electron energy loss spectroscopy (EELS) and is contrasted to an fcc-Cu reference sample. The experimental EEL spectra are compared to spectra computed by density functional theory. The main differences between bcc-and fcc-Cu are related to differences in van Hove singularities in the electron density of states. In Cu-Cr solid solutions with bcc crystal structure a single peak after the L3-edge, corresponding to a van Hove singularity at the N-point of the first Brillouin zone is observed. Spectra computed for pure bcc-Cu and random Cu-Cr solid solutions with 10 at% Cr confirm the experimental observations. The calculated spectrum for a perfect Cu50Cr50 (at%) random structure shows a shift in the van Hove singularity towards higher energy by developing a Cu Cr d-band that lies between the delocalized d-bands of Cu and Cr.
10.1016-j.ultsonch.2019.01.029	0	solidification; phase; magnetic; magnetic field; undercooling; field; liquid; separation; peritectic; immiscible; cu-; dendrite; phase separation; microstructure; primary	The effect of power ultrasound on the liquid phase separation of ternary Cu-32%Sn-20%Bi immiscible alloy is experimentally investigated, which shows that as compared with the layered structure formed under static condition, the macrosegregation resulted from liquid phase separation is remarkably reduced with the increase of ultrasonic amplitude. A homogenous microstructure characterized by refined (Bi) particles dispersing uniformly on the (Cu3Sn) matrix is obtained when the ultrasonic amplitude reaches the highest value of 24 mu m. This is mainly ascribed to the ultrasonically induced cavitation and acoustic streaming, which promotes the nucleation, the fragmentation, and the dispersion of (Bi) droplets. The finally solidified immiscible alloy exhibits obvious improvements in electrochemical corrosion resistance, microhardness and wear-resisting if compared with those in static solidification. These results prove that applying power ultrasound is an effective way to modulate the liquid phase separation and enhance the applied performance for immiscible alloys.
10.1016-j.ultsonch.2021.105593	2	corrosion; surface; film; electrochemical; films; spectroscopy; layer; current; solution; potential; resistance; composition; x-ray; ions; showed	Copper-based coatings are known for their high antibacterial activity. In this study, nanocomposite Cu-Sn-TiO2 coatings were obtained by electrodeposition from an oxalic acid bath additionally containing 4 g/dm(3) TiO2 with mechanical and ultrasonic agitation. Ultrasound treatment was performed at 26 kHz frequency and 32 W/dm(3) power. The influence of agitation mode and the current load on the inclusion and distribution of the TiO2 phase in the Cu-Sn metallic matrix were evaluated. Results indicated that ultrasonic agitation decreases agglomeration of TiO2 particles and allows for the deposition of dense Cu-Sn-TiO2 nanocomposites. It is shown that nanocomposite Cu-Sn-TiO2 coatings formed by ultrasonic-assisted electrodeposition exhibit excellent antimicrobial properties against E. coli bacteria.
10.1016-j.ultsonch.2022.106247	2	corrosion; surface; film; electrochemical; films; spectroscopy; layer; current; solution; potential; resistance; composition; x-ray; ions; showed	At present research, we highlight ultrasonic treatment as a new way to create materials with a gradient change of chemical or physical properties. We demonstrate the possibility to fabricate novel materials with biocide activity based on simple and cheap Cu-Zn alloy. In this research, we propose a green preparative technique for the sonication of an alloy in an alkali solution. The method leads to a significant visual change and differentiation of particles into three different fractions. Due to the chemical micro gradients in media near the solid surface under intensive sonication, fast formation of specific functional groups occurs on the particles' surface. The particles were studied X-ray diffraction analysis (XRD) analysis, the field-emission scanning electron microscope (SEM) as well as electron backscatter diffraction (EBSD) mode, X-ray Photoelectron Spectroscopy (XPS), the differential pulse anodic stripping voltammetry (DPASV) technique. A strong correlation of both methods proves a redis-tribution of copper ions from Fraction I to Fraction III that influence for the antibacterial properties of the prepared material. The different biocidal activity was demonstrated for each separated Fraction that could be related to their different phase content and ability to release the different types of ions.
10.1016-j.vacuum.2005.01.010	2	corrosion; surface; film; electrochemical; films; spectroscopy; layer; current; solution; potential; resistance; composition; x-ray; ions; showed	Due to its enormous technological importance there is a renewed interest in the oxidation of copper. However, due to the complex nature of oxidation of copper, the existence and importance Of Cu3O2, which is a metastable defect structure Of Cu2O, have not gained enough attention from researchers working on the oxidation of copper or copper alloys. The evidence for the Cu3O2 phase has been utilized to reinterpret previous Pulse Field Desorption Mass Spectrometry (PFDMS) and X-ray Photoelectron Spectroscopy (XPS) data. With additional Linear Sweep Voltammetry (LSV) and Galvanostatic Reduction (GR) data, an attempt has been made to delineate the complex nature of the oxidation of copper based on the Modified Cabrera Mott (C-M) Model. It is also emphasized that surface scientists should recognize Cu3O2 in new studies on copper oxidation and in interpreting already existing copper oxidation data. Need for more vacuum and low-pressure-based studies is stressed to characterize the distinct overlayers that can be formed by temperature and pressure control. Surface studies of oxidation of metals and alloys need to be supported and complemented by other techniques such as chemical and electrochemical methods.
10.1016-j.vacuum.2011.02.001	-1		The work functions of Cu, Cr, Mo and CrMo were calculated utilizing the first principle. The effect of Mo addition on the microstructure of CuCr50 alloy was characterized by a scanning electron microscope, and the arc motion characteristic was recorded and investigated by a digital high-speed video camera. The calculated results show that the selectivity of breakdown is closely related to the work function of close-packed plane. The experimental results show that Mo addition can strengthen Cr phase, the first breakdown transfers from Cr phase to Cu phase, and the cathode spots present the characteristics of division and deviation, thus avoiding concentrated erosion. In addition, the chopping current is reduced and the breakdown strength is enhanced as well.
10.1016-j.vacuum.2013.04.004	-1		In this study, a molecular dynamics (MD) simulation is carried out to obtain glass formation and icosahedral order for Cu-%50Ni model alloy system with 10,976 atoms based on embedded atom model (EAM) during the cooling processes. The structural development and icosahedral order of alloy system are analysed with the radial distribution function (RDF), the bond orientational order parameters and Honeycutt-Andersen (HA) bond-type index method. By looking into the amorphous-type bonded pairs within the atomic clusters and by analysing bond orientational order parameters (icos Q(6) and icos (W) over cap)(6), the icosahedral order is investigated under different cooling processes for the model alloy system.
10.1016-j.vacuum.2016.09.008	-1		Dual magnetron sputtering and thermo plasma nitriding were performed to fabricate Cu-Ti-N coating on the surface of Cu substrate, and the microstructure formation and evolution mechanism were investigated. The results showed that the composition of the Cu-Ti coating could be tuned to be around Cu:Ti = 1:1.2 by the appropriate choice of sputtering power for the dual targets, and only amorphous Cu Ti phases formed. During the thermo plasma nitriding process, crystalline CuTi and Cu3Ti occurred. Moreover, a nitride layer of about 0.3 mu m containing nanocrystalline TiN formed on the surface, and the multi-phase coating developed to be about 4 gm, which could provide better support for the nitrided layer.
10.1016-j.vacuum.2017.09.017	8	hot; deformation; strain; strain rate; dynamic; hot deformation; recrystallization; dynamic recrystallization; flow; rate; flow stress; compression; constitutive; degrees; stress	Hot deformation behavior of the Cu-Zr-Nd alloy was studied by using compressive tests in the temperature range of 550-900 degrees C and the strain rate range of 0.001-10 s(-1) on the Gleeble-1500D thermomechanical simulator. The Cu-Zr-Nd alloy flow stress increased at higher strain rate and lower temperature. Based on the processing maps and microstructure, the optimal processing parameters for the Cu-Zr-Nd alloy are determined as 750-870 degrees C and 0.001-0.03 s(-1). The addition of Nd can promote the dynamic recrystallization. A new constitutive model, which compensates for the strain rate, is established according to the Arrhenius-type equation. The Zener-Hollomon parameter was also modified to compensate for the strain rate. The flow stress predicted by the constitutive equation is consistent with the experimental flow stress.
10.1016-j.vacuum.2017.09.042	15	aging; strength; conductivity; electrical conductivity; electrical; mpa; treatment; strengthening; degrees; cu-; cold; precipitation; tensile strength; tensile; iacs	The Cu-0.6Cr-0.2Zr alloy has been used as a new coil material to improve the performance and service life of coils in an electromagnetic steel-teeming system. The purpose of this work was to improve the properties of the Cu-0.6Cr-0.2Zr alloy to satisfy the coil requirements of a high strength and a high conductivity. For studying the effect of heat treatment on the properties of Cu-0.6Cr-0.2Zr alloy, the copper alloy was exposed to heat treatments of cold deformation and aging after high-temperature solid solution. The effects of aging treatment on the properties of the Cu-0.6Cr-0.2Zr alloy at different cold deformations were examined by a tensile mechanical-property test, electrical-conductivity measurements, microstructure observations and SEM. The Cu-0.6Cr-0.2Zr alloy has optimal comprehensive properties after solution treatment at 960 degrees C for 1 h, and 50% cold deformation and aging at 450 degrees C for 6 h, and the hardness, strength, elongation and electrical conductivity reached 225.2 HV, 522.7 MPa, 8.3% and 89.5% IACS, respectively.
10.1016-j.vacuum.2017.09.044	-1		Surface mechanical attrition treatment (SMAT) was used to produce gradient nanostructure in CuCr25 alloy. A gradient structure up to 200 gm thick in its surface layer with grain size from nano-scale to micro-scale was obtained. The microstructural features of the surface layer produced by SMAT were systematically characterized. The average Cr and Cu grain size of the top surface layer was about 10 nm. The hardness of the SMATed surface layer after annealing treatment reached 475 HV which was three times higher than that of the original sample. The electrical conductivity of annealing sample was 46.5% IACS which was better than that of other nanocrystalline CuCr alloys. The SMAT treatment provides a new approach for preparation of CuCr alloy vacuum interrupters with high surface hardness and high electrical conductivity.
10.1016-j.vacuum.2017.10.011	-1		In this work, we studied the microstructure formation and mechanical properties of the Ti alloyed C17200 Cu surface produced by plasma nitriding at 750 degrees C. The results firstly show that the multiphase coating consists of amorphous and nano-crystalline phases, and various types of Cu-Ti intermetallics, including CuTi2, CuTi, Cu3Ti2, Be3Ti2Cu, Cu2Ti, Cu3Ti, formed after the plasma nitriding at 750 degrees C. The formation of the specific type of Cu-Ti intermetallic depends on the processing duration, where a longer duration contributes to the formation of intermetallics with a higher Cu/Ti ratio. The evolution of the phase compositions is responsible for the change in the mechanical properties. The surface hardness of the modified C17200 Cu alloy improves to be 400 HV0.01 to a depth of 15 mu m after plasma nitriding for 6 h, which contributes to a higher surface tribological resistance with a friction coefficient of 0.3 and a wear rate of 4.15 x 10(-9) g/(r.N) for the modified suface.
10.1016-j.vacuum.2017.12.011	-1		Cu-15Cr and Cu-15Cr-0.24Zr alloys were prepared by means of vacuum medium frequency induction melting technology. The effects of Zr on the as-cast microstructure of Cu-15Cr alloy were studied by means of scanning electron microscopy (SEM), energy dispersive spectroscopy (EDS) and transmission electron microscopy (TEM). Besides, the effect of Zr on the tensile strength and electrical conductivity of Cu-15Cr alloy was also studied after heavy drawing deformation. The experimental results show that the addition of Zr leads to the formation of thin CuZr compound phase. Moreover, the formation of eutectic Cr phase is inhibited, so that the content of eutectic Cr is much lower than that of Cu-15Cr alloy. The size of dendritic Cr is refined as well. Furthermore, the addition of Zr improves the tensile strength of the alloy, which has little effect on the electrical conductivity. It is observed that when the dependent variable eta is 6.44, the tensile strength and electrical conductivity of the alloy can reach 1023 MPa and 72 % IACS respectively, which increases 117 MPa and reduces only by 2 %IACS.
10.1016-j.vacuum.2017.12.035	-1		In this work, Cu-Cr alloys have been prepared by reducing reaction of Cr2O3 with Cu-Mg melt. The thermodynamic analysis of the reaction system and the microstructures of alloys were carried out. The results show that Cu-Cr alloys with around 0.57 wt%-4.92 wt% chromium content can be prepared by in situ synthesis technique. And Cr particles with anomalies forms have been observed, which illustrated that part of Cr particles is not formed by classical nucleation and crystal growth . In addition, the influence of thermomechanical treatments on microstructure and properties of the Cu Cr alloy was also discussed. The results show that cold rolled before aging can accelerate the speed of decomposition of Cr from supersaturated matrix and finer precipitates are obtained in CR-80%-A sample than STA sample. Moreover, the good combination of the properties, such as microhardeness of around 171HV, tensile strength of around 475 MPa as well as electrical conductivity of around 86.2% IACS were obtained in CR-80%-A sample.
10.1016-j.vacuum.2018.05.010	-1		Continuous columnar-grained Cu-Ag alloy bars containing different silver contents (6 wt%, 12 wt%, 24 wt%) with diameters of 10 mm were prepared by directional solidification technology firstly and drawn to 0.3 mm directly at room temperature without intermediate annealing in this study. With incremental Ag contents, eutectic microstructure distributed in the interdendritic region which parallel to the casting direction grew with a higher tensile strength but almost invariable elongation and electrical conductivity of the alloys. Meanwhile, the tensile strength of the alloy wires were enhanced greatly with increasing drawing strains owing to the remarkable fiber reinforcement effect, whereas the elongation and electrical conductivity decreased slowly. With the increase of drawing strains, columnar grains and eutectic phases were drawn into dense microcomposite structure, and the volume fraction of < 111 > texture in Cu and Ag phases increased in the three experimental alloys; while, the growth rate of < 111 > texture in Ag phases was lower than that in Cu phases, which is one of the main reasons for the excellent ductility of the alloys. These results may offer reference for the choice of Ag content and drawing strain, and then developing a short preparation process of Cu-Ag alloys with directional solidification + drawing (without intermediate annealing).
10.1016-j.vacuum.2018.05.016	-1		Ni, Fe and Co were added in 75% Cu-25% Sn alloys respectively for improving its microstructures and properties and decreasing the large weight loss of specimens in the high hot pressing temperature. Densification and mechanical tests were performed, and structures were investigated by X-ray diffraction, energy dispersive spectroscopy and scanning electron microscopy. When the hot pressing temperature was more than 700 degrees C, there were few weight loss of specimens with Ni added, a few weight loss of specimens with Fe added, and the large weight loss of specimens with Co added. All the Ni was dissolved in the Cu and delta-phase. Few Fe was dissolved in the Cu and delta-phase and most of Fe formed a single-phase. A portion of Co was dissolved in the Cu and delta-phase while the rest formed a single-phase. The fracture of all the specimens was brittle. The wear resistance and TRS increased due to the solution strengthening of Ni.
10.1016-j.vacuum.2018.06.006	8	hot; deformation; strain; strain rate; dynamic; hot deformation; recrystallization; dynamic recrystallization; flow; rate; flow stress; compression; constitutive; degrees; stress	The effects of Ce addition on the Cu-Mg-Fe alloy hot deformation process were investigated through the isothermal compression tests using the Gleeble-1500D thermo-mechanical simulator at 500-850 degrees C temperature range and 0.001-10 s(-1) strain rate range. The interaction of work hardening, dynamic recovery and dynamic recrystallization during plastic deformation was studied, and the constitutive equations of Cu-Mg-Fe and Cu-Mg-Fe-Ce alloys were established. The addition of Ce can delay the occurrence of dynamic recrystallization, enhance the flow stress and apparently narrow the unstable domain during hot deformation process of the Cu-Mg-Fe alloy. Two optimal hot working parameters for the Cu-Mg-Fe alloy are obtained. The first is temperature of 650-800 degrees C and strain rate of 0.001-0.01 s(-1), and the second is temperature of 775-850 degrees C and strain rate of 0.01-0.6 s(-1). The optimal hot working parameters for the Cu-Mg-Fe-Ce alloy are 675-850 degrees C and strain rate of 0.01-0.4 s(-1). The precipitate of the Cu-Mg-Fe-Ce alloy deformed at 850 degrees C and 0.001 s(-1) was determined to be CuMg2. CuMg2 precipitation can improve the hardness and hot deformation activation energy of the Cu-Mg-Fe alloy. Meanwhile, the addition of Ce can promote the precipitation of CuMg2.
10.1016-j.vacuum.2018.10.054	15	aging; strength; conductivity; electrical conductivity; electrical; mpa; treatment; strengthening; degrees; cu-; cold; precipitation; tensile strength; tensile; iacs	The properties of Cu -0.2 wt%Zr-0.15 wt%Y alloy aged at 400 C, 450 C, 500 C, 550 C for 0 h, 0.25 h, 0.5 h, 1 h, 2 h, 4 h and 6 h after 0%, 20%, 40%, 60% cold rolling were investigated systematically by the transmission electron microscopy (TEM) and selected area electron diffraction (SAED) in this study. The hardness and electrical conductivity were measured under different conditions. The optimum ageing process for the alloy was determined. After solution treated at 900 C for 1 h, the studied alloy with 60% cold rolling can obtain the best properties after aging treatment at 450 C for 1 h . It means the conductivity can reach to 90.6 %IACS and the hardness reach to 145.0 HV. The ageing hardening behavior was also analyzed according to the transmission microstructures. A large amount of Cu10Zr7 precipitates were identified by TEM analysis in the copper matrix. The phase transformation kinetics equations for Cu -0.2 wt%Zr-0.15 wt%Y alloy was established under different aging temperature after 60% cold rolling. The kinetics curves of aging precipitation and isothermal transformation were obtained. In addition, the small addition of Y can promote the precipitation of the second phase.
10.1016-j.vacuum.2018.11.060	-1		The transition region in worn surface of a 2.86 wt%Cr iron alloy was investigated under dry impact wear test, and apparatus consist of repeated impact of a pin specimen on a rotating grinding wheel with abrasive. Results show a convex surface is formed in transition region, and its altitude reaches maximum after 6000 impacts. That effect causes the thickness loss of entire worn surface declines from 22.34 pm of 0-2000 impacts to 18.87 mu m of 4000-6000 impacts. However, the convex surface is replaced by a concave surface after 9000 impacts, and it propagates to region 2 subsequently. When the theta between concave morphology near region 2 and horizontal direction is greater than 90, impact wear resistance starts to fail, and 8 will not increase until worn surface splits away off completely. In addition, the resistance behavior above will restart on new worn surface.
10.1016-j.vacuum.2019.01.012	2	corrosion; surface; film; electrochemical; films; spectroscopy; layer; current; solution; potential; resistance; composition; x-ray; ions; showed	The paper discusses the preparation of multicomponent thin films of Cu-Ti composite with desired elemental composition using the pulsed magnetron co-sputtering technology. The technological goal described in the paper was deposition the Cu-Ti composite with elemental ratio of about 50/50 at%, which is close to the eutectic point from the Cu-Ti alloy system. A large difference in the sputtering yield (about seven-fold) of Cu and Ti metals was challenging, because of the features of used power supplies. Desired concentrations of the Ti and Cu elements were obtained as a result of application of multimagnetron sputtering system, where magnetrons were equipped with the Ti or Cu targets. Additionally, pulse power supply was used together with the pulse width modulation controller. Moreover, the article presents investigations of structural and mechanical properties of deposited Cu, Ti and Cu-Ti films with elemental composition of ca. 50/50 at%. It was found that the two component Cu0.5Ti0.5 thin films were composed of Cu4Ti3 nanocrystallites built-in an amorphous matrix. As compared to the pure Cu and Ti thin films, the prepared composite exhibited improved hardness and better elasticity reflected in lower values of the Young's modulus. The results of nanoindentation investigations showed that the Cu0.5Ti0.5 composite thin film was characterized by the hardness of 7.59 GPa.
10.1016-j.vacuum.2019.05.030	15	aging; strength; conductivity; electrical conductivity; electrical; mpa; treatment; strengthening; degrees; cu-; cold; precipitation; tensile strength; tensile; iacs	Focus on the preparation process of Cu-14Fe deformation processed in-situ composite, by studying the stage of solidification, deformation, and heat treatment, the evolution of microstructure and the improvement of material properties have been investigated. The primary Fe phase distributed parallel on the longitudinal section and bent on the cross section under the shear stress, finally form the lamellar fiber structure in the deformation process. With cumulative cold deformation strain, the enhancement of tensile strength is attributed to the combined action of fiber strengthening, dislocation strengthening and precipitation strengthening. The strengthening mechanism of Cu-Fe deformation processed in-situ composites follows Hall-Petch relation with heavy strain. Due to the resistivity depends on the influence of impurity scattering and dislocation scattering, the intermediate heat treatment can improve conductivity effectively.
10.1016-j.vacuum.2019.06.017	-1		In this paper, a comparative study is reported on tool wear morphology described by machining Be/Cu alloy at different cutting speed:200 m/min,400 m/min,600 m/min,800 m/min and 1000 m/min. The cemented tungsten carbide tools, both coated with TiAlN, are used to test tool life, and the flank wear extent and standard deviation are adopted to describe surface wear pattern. In order to explain the wear mechanism under different cutting speed, a series of theoretical calculation and experiment results were listed in this paper to explain adhesive effect on tool wear under different surface pressure, and results show that the adhesions and wear patterns would be affected by cutting speed and surface pressure. Comparing the relationship between cutting force, cutting heat, surface elements and tool wear, we can easily find out that the hard particle such as Cu and Be adhered to cutting edge to affect tool geometry and strengthen. Besides, the microstructure and generation probability are analyzed to discuss the crystal surface slipping effect on tool wear.
10.1016-j.vacuum.2019.06.027	-1		To balance the paradox of both high mechanical properties and electrical conductivity of copper alloys, a nominal hot-rolled Cu-0.4 wt%Cr-0.3 wt%Zr alloy strips were subjected to different thermo-mechanical process. The microstructures of the alloys are characterized by optical microscopy and transmission electron microscopy and the mechanical properties and the electrical conductivity are evaluated. The results show that a desired combination of strength, ductility and conductivity can be obtained by controlling the sequence of cold rolling and aging. It suggests that the treatment route with an order of aging followed by cold rolling (ACR) is better than that with the order of cold rolling with aging (CRA). The ultimate tensile strength 568 MPa and electrical conductivity 75.3%IACS are obtained after aging at 450 degrees C for 3 h followed by 80% cold rolling at room temperature. The high electrical conductivity and ductility is attributed to twin lamellar structure.
10.1016-j.vacuum.2019.06.033	-1		Cu-Ti alloys synthesized in the surface layer of copper by means of preliminary Ti coating deposition and subsequent treatment by compression plasma flows have been investigated in this work. X-ray diffraction, scanning electron microscopy, energy-dispersion X-ray microanalysis, Auger electron spectroscopy, Vickers microhardness measurements and tribological tests were used for Cu-Ti alloys characterization. The findings showed that the increase of the energy absorbed by the surface layer during plasma treatment from 57 to 74 J/cm(2) per pulse resulted in the growth of the alloyed surface layer thickness from 15 to 19 mu m, more homogeneous distribution of T1 in the alloyed layer and the decrease of Ti average concentration from 13.1 to 9.7 at% in it. The supersaturated solid solution of titanium in copper was the main phase constituent of the alloyed layer after treatment at 74 J/cm(2). The synthesized surface of the Cu-Ti alloy possessed enhanced strength and tribological properties.
10.1016-j.vacuum.2019.108913	-1		In this study, the effect of novel metal tantalum was investigated on the properties of copper-graphite composites. The complete mechanical behavior of copper-tantalum-graphite hybrid composites was examined. The addition of tantalum increased the compressive, tensile and bending strength of composites as well as the hardness and thermal conductivity. The compression, tensile, bending and hardness values for Cu-Ta-GF (0.5) composites are 20.7%, 138%, 69% and 93% higher than pure Cu and these are also far better than Cu-GF composites. The excellent mechanical and thermal properties with good relation of strength-ductility ratio open up a new window to use these materials as heat sinks in thermal packaging system.
10.1016-j.vacuum.2019.109032	-1		Cold spraying is used to deposit coatings on a copper substrate with mixed Cu-Cr composite powders. The morphology evolution of Cu and Cr phase during cold spray is studied. And the mechanical properties of Cu-Cr coating is researched. Results indicate that ductile copper shows heavy plastic deformation, brittle chromium shows some crack and even break during cold spraying. Cold sprayed coatings show a good adhesion with substrate and a homogeneous distribution of Cr particles in the microstructure. The Cr contents of coatings are 13.06%-16.01% which obviously reduce compared to feedstock (45.00%) due to the high hardness and poor deformation. The hardness of Cu-Cr coatings is 145.7 HV. Copper further deform during the wear process while chromium show evidence of brittle fracture. The dominant wear mechanism for the Cu-Cr coatings is plastic deformation and delamination. The electrical conductivity of pure Cu coatings and Cu-Cr coatings are 73.28% and 53.49% IACS, respectively. Cu-Cr coatings have similar hardness and electrical conductivity as of Cu75Cr25 alloy ingots (VIM). The results indicate that cold spray technique provides an effective approach to manufacture uniform and dense Cu-Cr coatings with accepted physical and mechanical properties.
10.1016-j.vacuum.2019.109123	-1		To achieve an enhancement of mechanical properties, the WCu composite reinforced with short tungsten fibers was advocated. Characteristics including phase constituents, microstructure and mechanical properties (tensile, compressive and frictional behaviors) of the W-f reinforced WCu composite have been systematically investigated. The magnetron sputtered Ti layer on the surface of W-f effectively improved the sinterability of the composite, leading to excellent electrical conductivity of 56.55% IACS and hardness of 182 HB. Cross sectional EBSD results clearly reveals the sharp <110> fiber texture according to the {110} pole figure of the W-f part, indicating a reserved texture structure although after high-temperature sintering and infiltration, which ensures the fiber strengthening effect. Further tests confirmed the enhancement of mechanical properties including high tensile strength of 549.0 MPa and compressive strength of 1047.8 MPa with large plasticity, as well as low friction coefficient of 0.494. A three dimensional model via numerical simulation further revealed that the smaller the angle between the axial direction of the inserted fibers and the loading direction, the easier it was to bear a higher stress, and the middle part of the fiber was more vulnerable to the accumulated damage.
10.1016-j.vacuum.2020.109485	-1		It is of practical importance to avoid coarse precipitation in the Cu-Cr alloys during vacuum melting and casting processes. The present study indicates that minor C addition can eliminate the coarse Cr dendrites and refine the Cr phase in the Cu-Cr alloys. The reason behind this is analyzed by using the calculation of phase diagram and attributed to the occurrence of liquid phase separation induced by the C addition.
10.1016-j.vacuum.2020.109620	-1		By virtue of spherical initial powders, novel W-Cu composite alloys of W60Cu40 and W70Cu30 have been fabricated by successive processes of powder mixing, cold pressing, sintering and infiltration under hydrogen atmosphere in this work. The phase composition and distribution, hardness, electrical conductivity and tensile behavior of the resultant composite alloys were investigated. Results revealed that the resultant W-Cu composite alloys exhibited excellent hardness improved by 7.3% (4.6%) and remarkably improved electrical conductivity by 23.3% (23.8%), compared with present commercial alloys. Further tensile tests revealed the superior strength of 423 MPa (485 MPa) with reliable strain of 8.8% (7.6%), which can be ascribed to the homogenous structure with alternate soft/conductive Cu and hard W phases free from blind holes.
10.1016-j.vacuum.2020.109895	16	wear; composite; composites; powders; milling; particles; powder; wt; sliding; friction; hardness; matrix; mechanical; surface; properties	Hypothesis of this research focuses on evaluating mechanical properties and thereby determine optimized conditions for lessened wear rate of powder metallurgy processed Titanium diboride (TiB2) reinforced Cu-W alloy matrix composites. Tungsten and Titanium diboride powders were mixed with copper powder to the state of homogeneity by mechanical alloying method, compacted in a computerized hydraulic press and further sintered at 900 degrees C for 2 h under argon environment. SEM studies revealed that TiB2 particles were disseminated evenly in Cu-W alloy. The fabricated composites were subjected to EDS and XRD studies to confirm the presence of required elements and the occurrence of oxides formed while sintering. The impact of wear test input parameters on the wear rate was identified and the optimized parameter to attain low wear rate was determined through Taguchi and ANOVA analysis by using L16 orthogonal array. The hardness, impact strength, compressive strength, and wear resistance of the composites experience considerable enhancement, with the inclusion of TiB2 particles. The optimized parameters to achieve less wear rate was arrived as A(4)B(1)C(1)D(1) and the composite with 12 wt% TiB2 content subjected to 10 N load with 1 m/s velocity and 300 m sliding distance attained minimum wear rate.
10.1016-j.vacuum.2020.110002	-1		In this work, the effect of the third addition (Ag, Mn, Si, and Sn) on the wettability and the interfacial structures of Cu-20Me-2Cr/SiC systems was investigated. The third addition Me has the obvious effect on the wettability and the spreading dynamics. The sequence of effectiveness is Sn > Ag > Mn > Si. Si Addition can suppress the precipitation of the wettable reaction products, and thus that caused the poor wettability. Although additions of Ag and Mn can improve the wettability significantly, a dissolution zone beneath the reaction layer would be formed. When the third addition Me was thermodynamically repulsive with Si. Meanwhile, the critical concentration of Si in liquid for equilibrium with SiC was less than the corresponding amount of graphite consumed by Cr addition. The dissolution zone would be suppressed. Sn addition satisfied this situation, and thus the best wettability can be achieved. The spreading of Cu-20Me-2Cr/SiC was controlled by the decomposition of SiC rather than the precipitation reaction.
10.1016-j.vacuum.2021.110156	-1		To clarify the effect of aging treatment on the microstructure and properties of Cu-3Ti-2Mg alloy, a Cu-3Ti-2Mg alloy ingot was fabricated, followed by homogenizing at 800 degrees C for 10 h, solubilizing at 750 degrees C for 4 h and aging at different temperatures. The microstructure was characterized by SEM, EPMA, TEM, 3D laser scanning microscope and Raman spectroscope, and the mechanical properties, electrical conductivity and tribological performance of Cu-3Ti-2Mg alloy was tested. The results showed that the diffraction peaks of Cu gradually shift to the left with increase of the aging temperature, indicating Ti precipitate from the Cu matrix. The interfaces between precipitation phases and Cu matrix exhibit a clean and tight bond without visible defects. With increase of aging temperatures, more Ti precipitated from Cu matrix enhances the electrical conductivity, hardness and elasticity modulus are increased due to the formation of beta'-Cu4Ti, beta-Cu3Ti and Cu2Mg phase. Friction test indicated that the precipitation strengthening improves the wear resistance of the Cu-3Ti-2Mg alloy and the alloy after aging at 500 degrees C has the lowest wear rate of 2 x 10(-5) g/Nm. The Raman analysis revealed that the tribofilm formed on the wear surface is consisted of Cu2O. Based on the analysis for the mechanical properties and tribological behaviors analysis as the function of the aging temperature of the Cu-3Ti-2Mg alloy, it suggests that the synergistic effect between beta'-Cu4Ti phase and Cu2Mg phase endows the possibility for the alloy to be used under the conductive friction service condition.
10.1016-j.vacuum.2021.110369	-1		- This paper focuses on the development of copper-based shape memory alloy (SMA) coated optical fiber sensor. The developed sensors are having potential applications for condition monitoring in different systems. The Cu-Al-Ni (82%-14%-4%) SMA has been deposited on optical fiber with the help of flash evaporation. To have an efficient deposition, an in-situ fixture has been designed, which can induce strain and rotate the fiber to get a uniform coating. The samples are prepared by varying the rotational speed of the fixture between 24 and 36 rpm (rotation per minute) during deposition. The optical fiber deposited at a rotational speed of 24 rpm has achieved a maximum bending angle of 53 degrees. The actuation behaviour has been investigated in detail for varying load and voltage. Also, the surface morphology, thickness measurement and thermal analysis of coated and uncoated optical fiber have been investigated in detail. A complete review of test results showing the characteristics and performance of plastic optical fibers after coating with shape memory alloy has been provided in this paper. Static structural analysis has been performed in ANSYS workbench to observe the stress and strain developed during the bending of SMA coated fiber.
10.1016-j.vacuum.2021.110436	-1		High-strength and high-conductivity copper alloys have a wide range of applications, such as an important electrical contact material. In this work, Cu-Y2O3 composite material was prepared through solid-liquid doping, calcination reduction, and spark plasma sintering. The effect of different yttrium oxide content (1, 3, and 5 wt%) on the microstructure and mechanical properties of the composite was studied. Results showed that the surface of the calcined and reduced copper powder was uniformly covered with yttrium oxide particles. After spark plasma sintering, the relative density of the blocks almost reached 100%. With the increase in yttrium oxide content, the distribution of yttrium oxide transformed from dispersion to agglomeration, and the grain size gradually decreased. There is a good bond between the copper matrix and yttrium oxide, and the particle size of yttrium oxide particles is approximately 150 nm. In terms of mechanical properties, the Cu-3wt% Y2O3 sample obtained the best comprehensive mechanical properties with strength of 290.1 MPa, hardness of 125.7 HV, and conductivity maintained at a high level of 95% International Annealed Copper Standard (hereinafter called IACS).
10.1016-j.vacuum.2022.111568	2	corrosion; surface; film; electrochemical; films; spectroscopy; layer; current; solution; potential; resistance; composition; x-ray; ions; showed	A series of nanocrystalline Cu-Cr alloys was high-throughput synthesized onto micromachined cantilever arrays by magnetron co-sputtering. Based on the consistent relationship between film-induced stress and stress corrosion cracking (SCC) susceptibility, the effects of Cr content on the SCC susceptibility of Cu-Cr alloys in 0.2 M NH3 center dot H2O solution were determined via film-induced stress measurement. The results show that the film-induced tensile stress gradually decreased with the increasing Cr content, that is, the SCC susceptibility decreases. Chemical composition and phase composition of the corrosion product film formed on Cu-11.46 at% Cr alloy immersed in 0.2 M NH3 center dot H2O solution for 1 h were investigated.
10.1016-j.vacuum.2023.111819	-1		A nanocrystalline surface layer was fabricated on the surface of CuCr8 alloy by surface ultrasonic rolling treatment (USRT) with different rolling depth . The surface morphology, microstructure, hardness, surface strength and corrosion resistance were systematically characterized by using X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), and the corresponding test methods. The results showed that the USRT treatment did not change the surface phase of the CuCr8 alloy, but only refined the surface grain. The rolling depth had great influence on the surface properties of the CuCr8 alloy. When the rolling depth was 0.15 mm, the surface comprehensive performance was the best. The surface grain size was about 78 nm, the surface hardness was up to 120 HV0.05, the tensile strength reached to 400 MPa, and the corrosion performance was significantly enhanced. The content of Cr, CuO and Cu(OH)2 in the passivation film of the USRT treated alloy was higher than that of the CG alloy. The USRT treatment provides a new method for fabricating CuCr alloy vacuum break tubes with high surface properties.
10.1016-j.vacuum.2023.111897	-1		Grain size is a critical factor determining materials properties but is challenging to be quantitatively controlled especially in nanoscale. Here, we found the average grain size of pure Cu film can be enhanced from 23 to 557 nm with the preparation temperature increasing from 298 to 773 K during magnetron sputtering. The temperature effect is weakened after W addition to Cu matrix and the grain size of Cu96W4 samples just exhibits slight increase from 30 to 145 nm. The coupling effect of W alloying with temperature is related to the decreased diffusion of Cu atoms after W addition during magnetron sputtering process. Cu-W supersaturated solid solution is formed at low temperatures (below 773 K for Cu96W4 or 573 K for Cu94W6) but W atoms could be agglomerated at elevated temperatures. Moreover, after He ions irradiation at 673 K, fewer and smaller cavities are formed in Cu96W4 samples compared to pure Cu, indicating that W addition could significantly enhance irradiation tolerance.
10.1016-j.vacuum.2023.112355	-1		In order to solve the discontinuous precipitation of nano-spherical & gamma;& PRIME; coherent precipitates strengthened Cu-Ni-Al alloys and explore the influence mechanism of trace elements on the microstructure and properties. Herein, the Si and Sn, with same main group but showing different elemental interaction, was selected as the fourth element, and series of alloy composition were designed and prepared in a wide Cu content, and the effect of Si or Sn addition on microstructure, properties at room temperature and thermal stability are investigated. The results demonstrate that Si is completely dissolved into & gamma; and & gamma;& PRIME; phase, but a little of Sn solid solution into & gamma;& PRIME; phase. The two adding elements can accelerate the precipitation of & gamma;& PRIME; phases, suppress the grain boundaries discontinuous precipitation and provide dual-nanostructure strengthening effect, which enhance the hardness and conductivity, and Si exhibits more preferable effect. The thermodynamic calculation and the work function results indicate that the addition of Sn would induce the descending thermal stability of & gamma; and & gamma;& PRIME; phase, but Si is beneficial to the improvement of thermal stability of & gamma; and & gamma;& PRIME;phase. Compared to Sn, Si is more suitable to be a candidate for the multi-component design of Cu-Ni-Al alloys.
10.1016-j.vacuum.2023.112531	-1		For the advanced 2.5D/3D IC applications, the IMCs suppression and phase stability should be emphasized. With a reduced bonding height of microbumps, the IMCs would occupy a high volume fraction of the joints during the reflow process or operation. A high volume fraction of IMCs and excessive phase transition could induce internal stress and voids, which might be adverse to reliability of interconnection. The novel Cu-26Zn-18Ni/Sn-3.5Ag/ Cu-26Zn-18Ni (by weight) microbumps have been fabricated and the considerable inhibition on the IMCs and void formation was investigated. Four kinds of IMC were found in Cu-26Zn-18Ni/Sn-3.5Ag/Cu-26Zn-18Ni microbumps.: (Cu,Ni)6(Sn,Zn)5, (Cu,Ag)5(Sn,Zn)8, Ag3Sn and (Cu,Ni)Zn. The tough bulk (Cu,Ag)5(Sn,Zn)8 combined with solid solution strengthened and refined (Cu,Ni)6(Sn,Zn)5 grains as well as the void-free microstructure were expected to enhance the reliability of microbumps. The effect of Ag on the formation of tough (Cu, Ag)5(Sn,Zn)8 was also addressed. These findings provided insights into the design of substrate alloy in advanced electronic packaging reliability.
10.1016-j.vacuum.2023.112676	-1		The difficult Zn dendrite for Zn anodes remains a significant barrier. One of the most promising options is to create an artificial copper-zinc-aluminum (Cu-Zn-Al) alloy layer. However, creating a perfect Cu-Zn-Al alloy layer with an acceptable shape and adjustable thickness remains difficult. In this paper, a novel vacuum thermal deposition method (VTDM) is used to create a cubic, close-packed Cu-Zn-Al alloy layer with adjustable shape and thickness. Meanwhile, to demonstrate the alloying process, an irradiation mode is offered. Alloy base shapes of Cu-Al-Zn have been widely used in environmental applications due to their low cost, safety, and effectiveness. This research successfully produced the alloy base shape of Cu-Al-Zn by the vacuum thermal evaporation method with and without applied irradiation by gamma rays (NaI (Ti)). Cu-Al-Zn was produced to prevent detrimental effects on human health . The Cu-Al-Zn was characterized by XRD, SEM, mapping, and EDX analysis. The small crystalline size (11.8-40 nm) and (cubic) structure of the alloy base shape of Cu-Al-Zn before irradiation were explained by measurements of XRD, whereas the small crystalline alloy base shape of Cu-Al-Zn after irradiation was 11-23 nm. FESEM revealed that the particle size of the alloy base shape of Cu-Al-Zn before irradiation by the gamma rays (NaI (Ti)) was 41.34-195.91 nm and had a cubic structure, whereas the alloy base shape of Cu-Al-Zn after irradiation by the gamma rays (NaI (Ti)) was tiny and crystalline at 31.63-130.3 nm and had a ball-like structure.
10.1016-j.vacuum.2023.112723	-1		As Cu segregation is commonly known to negatively impact the comprehensive mechanical properties of Cucontaining high entropy alloys (HEAs), this study investigated the effects of transition elements on Cu segregation by adding X (X = Fe, Co, and Ni) into the precursor HEA, CrCuTiV. Cu segregation was observed in the cases of X = Fe or Co, but not for X = Ni or none (i.e., without element addition). Analysis indicates that Cu segregation results from the moderate valence electron concentration and positive mixing enthalpy in the X = Fe and Co alloys, which enhance the strength via solid solution strengthening but reduce the plasticity by promoting crack formation and propagation. In contrast, the precursor alloy CrCuTiV demonstrated an exceptional combination of yield strength (1456 MPa), plasticity (21.2%), and specific yield strength (218.3 kPa m3/kg). The study sheds light on the influence of similar 3d elements on Cu segregation and its impact on the mechanical properties, which may aid in the design and development of Cu-containing HEAs with optimized mechanical properties for various industrial applications.
10.1016-j.vacuum.2024.112973	14	strength; properties; conductivity; electrical; mechanical; cu-; grain; mpa; electrical conductivity; aging; precipitation; phase; mechanical properties; tensile; phases	In order to investigate the effects of matrix solid solution, precipitate phases, and microscale interfaces on the mechanical and electrical properties of copper alloys, we employed first -principles calculations based on density functional theory study aimed to understand how alloying elements enhance the strength and conductivity of copper. The results demonstrated that doping Co atoms into the copper matrix using the Dop2 structure model exhibited the most significant improvement in both mechanical and electrical properties. The Young's modulus was doubled compared to pure copper, and the hardness increased several times. The electrical conductivity reached 59.8 % of the International Annealed Copper Standard (IACS), showing a 6.6 % enhancement compared to Si doping. To validate computational results, we conducted experiments that confirmed the accuracy of the predicted mechanical and electrical properties. Furthermore, the introduction of Co effectively reduced electron losses at the interface between the precipitate phase and the copper matrix. The electron transmission rate through the Co2Si (211)/Cu (111) interface reached 78.6 %, representing a 94.1 % improvement compared to the Ni2Si (111)/Cu (111) interface. In conclusion, Co can simultaneously enhance the mechanical and electrical properties of Cu-Ni-Si alloys, providing theoretical guidance for the design and fabrication of high -strength and high -conductivity copper alloys.
10.1016-j.vacuum.2024.113014	-1		In this study, Cu-6Ni-1.5Si-xAl (x = 0 and 0.15 wt%) alloys are manufactured as billet materials by casting and their metallurgical and physical properties are characterized. Aluminum modified alloy is obtained also by a powder metallurgical (PM) route and its structural properties are determined to be compared with the cast materials. The findings indicate that (i) solidified alloys have distributed nickel silicides (27.01 %) embedded in alpha-Cu(Ni,Si) solid solution, (ii) the addition of aluminum increases the amount of silicides (29.09 %) in the solidified matrix and reduces both the grain size and the secondary dendrite arm spacing, (iii) although PM alloy has similar microstructural features as cast alloys, it exhibits the highest hardness (159 HV1) due to both finer grain structure and better distribution of silicides, (iv) both impurity and porosity have a determining effect on the electrical conductivity (27-32 % IACS, International Annealed Copper Standard) values of the alloys.
10.1016-j.vacuum.2024.113042	-1		Using the multi-principal element based high entropy alloy (HEA) concept, single-step ultra refinement and solidstate alloying of Cu with NiTi, Y, Fe, Cr, and Co were achieved simultaneously for the first time via friction stir processing (FSP). A bimodal microstructure with an average grain size smaller than 1.5 mu m was attained. The microstructure consisted of inter-dispersed regions of high and low density of geometrically-necessary dislocations. The fraction of high-angle grain boundaries was observed to increase from -33% in the unstirred region to -80% in the processed alloy. Intercalated bands having sharp variations in grain size were formed in conjunction with the bimodal microstructure. The entropic stabilization due to addition of diverse elements assisted multifaceted heterogeneity and grain refinement along. This study paves the way for the development of HEAs via FSP.
10.1016-j.vacuum.2024.113253	-1		In this paper, the effects of Mn element and rare earth element Gd on the microstructure, thermal stability, mechanical properties and shape memory effect of polycrystalline Cu-12.0Al-4.0Ni and Cu-12.0Al-4.0Ni-1.5MnxGd high-temperature shape memory alloy were investigated. The results show that the Cu-12.0Al-4.0Ni alloy exhibits millimeter-sized grain, dual-phase structure with coexistence of 18R and 2H martensite and poor thermal stability. When the Mn and Gd element was added to Cu-12.0Al-4.0Ni alloys, the grain size can be refined by an order of magnitude, and the 2H martensite disappeared completely, accompanied by the formation of the AlCu4Gd phase, meanwhile, thermal stability is significantly improved. The grain refinement improves the mechanical properties and shape memory effect of Cu-12.0Al-4.0Ni-1.5Mn-xGd alloys. When x = 0.3, the compressive fracture stress, compressive fracture strain and recoverable strain can reach 969 MPa, 15 % and 8 %, respectively.
10.1016-j.vacuum.2024.113369	14	strength; properties; conductivity; electrical; mechanical; cu-; grain; mpa; electrical conductivity; aging; precipitation; phase; mechanical properties; tensile; phases	The effects of Cu on the structure and properties of CuxCoCrFeNi were investigated experimentally and compared with the results of molecular dynamics simulations. Experimental results revealed that the alloy's crystal structure transitions from a single FCC to a biphasic FCC as Cu content increases. Mechanical testing indicated that increasing Cu content initially boosts, then reduces the alloy's yield and tensile strength, while elongation consistently increases, demonstrating enhanced plasticity. Additionally, nanoindentation tests further substantiated the notable impact of Cu content on alloy hardness. The nanoindentation simulation results show that the dislocation density increases and then decreases with the increase of Cu content, which explains the change of alloy properties with the increase of Cu content from a microscopic point of view. These findings offer valuable insights for designing and optimizing high-entropy alloys.
10.1016-j.vacuum.2024.113590	15	aging; strength; conductivity; electrical conductivity; electrical; mpa; treatment; strengthening; degrees; cu-; cold; precipitation; tensile strength; tensile; iacs	The effects of multi-element doping on mechanical and electrical properties of C7035 copper alloy were investigated by first principles calculation and experiment based on density functional theory (DFT). The results show that the addition of lanthanum (La) significantly improves the electrical conductivity of copper alloy, mainly because the precipitated phase of lanthanum (La) has high electrical conductivity, and promotes the formation of high-density twins in 0 Cu matrix. The electrical conductivity of the C7035 alloy doped with La reaches 80.19 % of IACS, which is 44.17 % higher than that of the alloy without La. In addition, the incorporation of scandium (Sc) increased the yield strength of the alloy to 635.63 MPa, an improvement of 25.65 %, due to the excellent mechanical properties of the ScCu4 precipitated phase. The highly conductive NiSi precipitated phase is formed by the copper alloy doped with La and Sc simultaneously. Compared with the undoped alloy, the yield strength and conductivity of the co-doped alloy are 672.27 MPa, 62.7 %, 32.89 % and 12.73 % respectively. In summary, the coupling doping of La and Sc improves the mechanical and electrical properties of C7035 copper alloy, which provides theoretical guidance for the design of high-strength and high-conductivity copper alloys.
10.1016-j.vacuum.2024.113651	-1		This work presents the development of two novel Cu-Zr-Mg(Y) alloys. The alloys were prepared using vacuum melting and show good conductivity and mechanical properties after solution treatment+60 % cold rolling + aging at 450 degrees C for 60 min. The measurement results reveal that the Cu-Zr-Mg alloy has a microhardness of 165 +/- 5 HV, an electrical conductivity of 68.5 +/- 0.2 % IACS and a tensile strength of 483 +/- 15 MPa while the Cu-Zr-Mg-Y alloy has a microhardness of 172 +/- 6 HV, an electrical conductivity of 67.9 +/- 0.2 % IACS and a tensile strength of 503 +/- 12 MPa. The addition of Y promotes the recovery and recrystallization of the alloys and causes the refinement of the grain size. The appearance of copper texture is the reason why the Cu-Zr-Mg-Y alloy has higher tensile strength in the rolling direction. The main phases of the Cu-Zr-Mg-Y alloy consist of Cu5Zr and a small amount of Mg24Y5. The increment in precipitation strengthening is primarily attributed to the coherent Cu5Zr phase within the matrix.
10.1016-j.vacuum.2024.113855	14	strength; properties; conductivity; electrical; mechanical; cu-; grain; mpa; electrical conductivity; aging; precipitation; phase; mechanical properties; tensile; phases	The transient liquid phase (TLP) bonding process is effective for constructing stacked structures in advanced packaging, as it allows for multiple reflow cycles without remelting. However, the various reflows can cause phase transformations, leading to internal stress-induced voids. Thus, the stability of IMC phases is particularly challenged in 3D stacking structures. Common configurations include Cu/Sn/Cu and Cu/Ni/Sn/Cu. Although Ni improves the stability of the Cu6Sn5 phase, phase transformation to Cu3Sn can still occur, compromising reliability. This study investigates microstructure stability by doping Zn into the Cu/Sn-3.5Ag/Ni system across five reflow cycles. Results demonstrate that Cu-15Zn/Sn-3.5Ag/Ni microbumps reduce void formation and ensuring the phase stability of the (Cu,Ni)6(Sn,Zn)5 to maintain the microstructure stability. The Zn addition inhibits the Cu3Sn layer, while optimizing grain size and orientation of (Cu,Ni)6(Sn,Zn)5. (Cu,Ni)6(Sn,Zn)5 also exhibits increased hardness and reduced modulus (Er). These findings provide critical insights for designing sub-10-mu m scale TLP-bonded microbumps in advanced packaging.
10.1016-j.vacuum.2024.113864	-1		Cu-9Ni-6Sn alloy exhibits profoundly potential as a new environmental-friendly conductive elastic material. In this work, the formation and growth mechanism of discontinuous precipitation, as well as its effect on mechanical properties of Cu-9Ni-6Sn alloy are systematically studied. The investigation indicated that the discontinuous precipitation does easily initiate from random grain boundaries but showing opposite result for Sigma 3 boundaries. The lower frequency Sigma 3 boundaries relatively, the more intense the solute diffusion, resulting in a higher volume fraction of discontinuous precipitation. The increasing aging temperature and time will accelerate the grain boundary discontinuous reaction, and the fine-grained samples exhibit a higher volume fraction of discontinuous precipitates and smaller lamellar spacing due to the more nucleation sites and increased interfacial energy. The strengthening mechanism of Cu-9Ni-6Sn alloy mainly focus on dislocation strengthening and precipitation strengthening, in which the D022 or γ′-gamma ' phases exhibit more significantly precipitation strengthening effect but is difficult to guarantee ductility. The localized grain boundary discontinuous precipitation detrimentally affect both the tensile strength and ductility. But the nano-lamellar discontinuous precipitation is beneficial to the strength-ductility trade off when it occupies the entirely Cu matrix. This work establishes a robust foundation for the microstructural optimization and multi-component design of Cu-9Ni-6Sn alloy.
10.1016-j.vacuum.2024.113889	-1		Functionally graded materials (FGMs) are new materials with great application prospects at present. To meet the requirements of this material in industry, such as excellent strength, hardness, ductility, and ability to work in extreme environments, it is of great significance to study the mechanical behavior of different functionally graded alloys at different temperatures. Furthermore, the growth of materials in a vacuum environment can be involved. In this paper, the functionally graded Cu-Ni alloy has been studied through molecular dynamics (MD). Six models with different content distributions are constructed by the sigmoid function. Their tensile, compressive, and nanoindentation simulations are carried out at 220K, 300K, and 420K. We found that the mechanical properties of Cu-Ni FGMs have a strong dependence on the Ni content. The strength and hardness increase with the increase of Ni content, while the ductility decreases with the increase of Ni content. As the temperature increases, Young's modulus of the material becomes smaller, but it has little effect on the nanoindentation simulation. We also found that the larger lattice constant of Cu leads to the first load value of the pure Cu model in nanoindentation simulation. Our research provides a basis for the design of FGMs and provides a method for exploring materials that can work at different temperatures.
10.1016-j.vacuum.2025.114101	-1		High-strength nanostructured copper alloys were fabricated through the mechanical consolidation of pure copper and Fe-Si-B glassy powders using a two-step high-pressure torsion (HPT) process. Structural characterization by transmission electron microscopy and electron backscatter diffraction revealed that, after overall 20 HPT revolutions, 1 wt% Fe78Si9B13 glassy powders can be fully decomposed and homogeneously supersaturated into the copper matrix. The resulting Cu-1 wt% FeSiB alloy exhibited a compositionally uniform nanostructure with an average grain size of 63.3 nm and a high proportion of low-angle grain boundaries (54.2 %), achieving an ultimate tensile strength of 1246 MPa. In contrast, the addition of 5 wt% Fe78Si9B13 glassy powder under the identical HPT conditions resulted in a crystal-glass composite structure with an ultimate tensile strength of 895.8 MPa. This work advances a hybrid method that integrates bottom-up particle bonding with top-down grain refinement to fabricate high-performance alloys.
10.1016-j.vacuum.2025.114183	-1		Within this paper, Cu-Co-W alloys with distinct Co concentrations were synthesized through mechanical alloying in conjunction with vacuum spark plasma sintering (SPS). The microstructural features, grain size parameters, and orientation characteristics of the alloy samples were analyzed via field-emission electron microscopy (FESEM), transmission electron microscopy (TEM), and electron backscatter diffraction (EBSD). The dynamic compressive properties of the alloys were tested by means of a Hopkinson pressure bar device. The phase composition, grain boundaries and geometrically necessary dislocation density of the dynamically compressed specimens were analyzed via EBSD. The research results show that during the sintering process, atomic diffusion occurs among Co and W, as well as W and Cu, generating solid solutions, namely Co0.9W0.1 and Cu0.4W0.6. Adding Co to Cu-W alloy can improve its density and refine the matrix grains. Meanwhile, the addition of Co can effectively improve the dynamic compression performance of Cu-W alloy. When the Co addition amount is 2 at%, an optimal balance of strengthening effects within different compression rate ranges can be achieved. The relevant mechanisms have also been studied and revealed.
10.1016-j.vacuum.2025.114362	-1		A high strength and high electrical conductivity Cu-2wt% Ag wire with a diameter of 0.03 mm was obtained by annealing at critical recrystallization temperature followed by heavily-deformed drawing process. The heterostructure comprising fine equiaxed recrystallized grains and thin filament-like deformed grains was designed for achieving such excellent properties. The ultimate tensile strength and electrical conductivity reached 1018 MPa and 80.5 % IACS, respectively. Large deformation resulted in the formation of a large number of layered structures within the Cu matrix grains, with a width of 40 nm. Simultaneously, Ag precipitates were elongated into slender fibers along the drawing direction, also contributing to the conductivity improvement. Our research provides a new strategy for the designing copper alloys with high strength and high conductivity.
10.1016-j.vacuum.2025.114371	-1		The microstructure, grain structure, and hydrogen embrittlement of age-hardened and laser-shock-peened Cu-TiFe alloys were investigated in this study. The alloys were age-hardened at 650 and 750 degrees C for 240 and 2400 min. Also, the age-hardened alloys were surface-modified by the laser shock peening (LSP) process with laser densities of 5.5 and 9 GW/cm2. The microstructural observation revealed the alpha-Cu4Ti and (3-Cu4Ti phases in all alloys. Additionally, higher aging temperatures and times resulted in a higher fraction of precipitates, especially the (3-Cu4Ti at grain boundaries. Furthermore, the hardness of alloys increased at higher aging temperature and longer aging times. Similarly, the higher laser density of LSP process resulted in a larger hardness increment. The peened surfaces showed grain refinement. The smaller grain size was obtained by applying a laser density of 9 GW/cm2. Also, peened surfaces reduced the hydrogen embrittlement. The crack propagation and cleavage fracture declined in peened surfaces, especially due to higher laser density.
10.1016-j.vacuum.2025.114373	-1		Selenium (Se) is widely known for its applications in glass production, medical treatments, and as a photoconductor. In this study, we found a new potential use of Se, namely, as a microalloying constituent for bulk metallic glasses (BMGs). By adding proper amounts of Se, we can enhance the glass-forming ability (GFA) and thermal stability of the Cu50Zr50 alloy, without compromising its excellent mechanical properties. However, once the Se content surpasses a certain threshold, it will lead to the preferential precipitation of a selenide phase, which catalyzes the formation of other intermetallic phases during casting and heating, thereby deteriorating the GFA and thermal stability. The use of Se in microalloying may provide new opportunities for the industrial applications of BMGs.
10.1016-j.vacuum.2025.114511	14	strength; properties; conductivity; electrical; mechanical; cu-; grain; mpa; electrical conductivity; aging; precipitation; phase; mechanical properties; tensile; phases	Cu-Fe in situ composites face Hall-Petch strengthening saturation when Fe filaments reach nanoscale dimensions. The present study addresses this limitation through a strategy of ultra-nano precipitation within nanolamellar architectures. By adding 0.2 wt% Mg to a Cu-10Fe alloy and applying multi-stage thermo-mechanical processing, a Cu-10Fe-0.2Mg in situ composite was developed, featuring ultrafine CuMg2 nanoprecipitates (similar to 6.8 nm) embedded in the Cu nanolamellar matrix. This optimized material achieves a 23 % strength enhancement compared to its Mg-free counterpart, while retaining 96 % of the base conductivity and comparable uniform elongation. The improvement in mechanical properties can be attributed to the Orowan strengthening effect from the introduced CuMg2 nanoprecipitates and their ability to promote work hardening. This ultra-nano precipitation within nanolamellae strategy is envisaged to be readily adaptable to other Cu-bcc in situ composites, offering broad implications for next-generation material engineering.
10.1016-j.vacuum.2025.114551	-1		This paper explores the effect of shot peening pressure (0.2, 0.5, and 0.8 MPa) on grain structure, hardness, and hydrogen embrittlement of age-hardened copper alloy. The micro-sized and nano-sized precipitates were observed in age-hardened alloy. The shot-peened surfaces showed higher hardness and refined grain structure than untreated surfaces. By increasing the peening pressure, the hardness increased while the grain size decreased. The maximum hardness values were 302, 311, and 325 HV after shot peening pressures of 0.2, 0.5, and 0.8 MPa, respectively. Also, the average grain sizes were 33, 25, and 18 mu m, respectively. In addition, the elongation of shot-peened alloys increased versus peening pressure. The elongation values increased from 18.5 % after the shot peening pressure of 0.2 MPa-23.5 % after the shot peening pressure of 0.8 MPa, respectively. In the presence of hydrogen, the fraction of brittle fracture decreased at higher peening pressure.
10.1016-j.vacuum.2025.114578	14	strength; properties; conductivity; electrical; mechanical; cu-; grain; mpa; electrical conductivity; aging; precipitation; phase; mechanical properties; tensile; phases	The coherent precipitation-strengthened Cu-Ni-Al ternary alloy exhibits high strength, high elasticity, and good electrical conductivity. Clarifying its resistivity-temperature behavior is essential. In this study, the microstructure evolution and the mechanism of resistivity-temperature behavior of Cu-Ni-Al ternary alloys was systematically analyzed. The results indicate that the microstructure of these alloys comprises a gamma matrix and a feather-like gamma ' coherent precipitation phase. The variable-temperature resistivity of the Cu-Ni-Al ternary alloy is closely associated with the total amount of (Ni + Al) dissolved in the gamma phase. Lower (Ni + Al) content reduces electron-electron scattering and phonon-electron scattering, thereby decreasing room-temperature resistivity. During the heating process, with the increase of Cu content, the slope of resistivity change with temperature gradually decreases, accompanied by a reduction in vacancy formation energy, which diminishes the thermal stability of the gamma phase.
10.1016-j.vacuum.2025.114754	14	strength; properties; conductivity; electrical; mechanical; cu-; grain; mpa; electrical conductivity; aging; precipitation; phase; mechanical properties; tensile; phases	This study investigates the segregation behaviour of Zn in Cu-Zn brass during pulsed laser surface melting (pLSM), through a combination of experiments and molecular dynamics (MD) simulations. Understanding the segregation phenomena is critical for tailoring surface properties in alloys, which has significant implications for improving material performance in demanding applications. Starting from a Cu90Zn10 random solid solution brass alloy, well-defined, Zn-rich annular regions that contain about 35 % Zn arise due to segregation during pLSM and subsequent solidification. MD simulations reveal that Zn atoms possess significantly higher mobility than Cu during both the melting and solidification stages, leading to pronounced surface segregation, corroborating experiments. This selective surface enrichment of Zn holds promise for enhancing corrosion resistance and surface hardness in brass alloys, paving way for further optimization of alloy compositions and laser processing parameters to achieve tailored surface properties in brasses and other alloy systems.
10.1016-j.wasman.2017.01.001	-1		High temperature pyrolysis investigations were carried out on waste printed circuit boards (PCBs) in the temperature range 800-1000 degrees C under inert conditions, with an aim to determine optimal operating conditions for the recovery of copper. Pyrolysis residues were characterized using ICP-OES analysis, SEM/EDS and XRD investigations. Copper foils were successfully recovered after pyrolysis at 800 degrees C for 10-20 min; the levels of Pb and Sn present were found to be quite low and these were generally present near the foil edges. The relative proportions of Pb and Sn became progressively higher at longer heating times due to enhanced diffusion of these molten metals in solid copper. While a similar behaviour was observed at 900 degrees C, the pyrolysis at 1000 degrees C resulted in copper forming Cu-Sn-Pb alloys; copper foils could no longer be recovered. Optimal conditions were identified for the direct recovery of copper from waste PCBs with minimal processing. This approach is expected to make significant contributions towards enhancing material recovery, process efficiency and the environmental sustainability of recycling e-waste. Pyrolysis at lower temperatures, short heating times, coupled with reductions in process steps are expected to significantly reduce energy consumption and pollution associated with the handling and processing of waste PCBs.
10.1016-j.wear.2004.11.013	16	wear; composite; composites; powders; milling; particles; powder; wt; sliding; friction; hardness; matrix; mechanical; surface; properties	The tribological behaviour of two Cu-Be alloys was investigated under dry sliding conditions against an AISI M2 steel counterface. The first alloy, Cu-Be 1, was characterized by a hardness of 390 HV and a thermal conductivity of 106 W/mK, whereas the second one, Cu-Be2, had a lower hardness, 270 HV, and a higher thermal conductivity, 208 W/mK. At low loads, wear was metallic in nature. The Cu-Be1 alloy displayed the lowest wear rate, as expected. As the applied load was increased, however, the wear rate of the Cu-Be I alloy increased, whereas the wear rate of the Cu-Be2 alloy was found to decrease and, in particular, to become lower than that of the Cu-Be I alloy. A transition in the wear mechanism from metallic wear to tribo-oxidative wear was observed as the applied load was increased. The results were explained in terms of the characteristics of the tribological layer, which forms during sliding on the surface of the Cu-Be specimens.
10.1016-j.wear.2006.05.020	-1		The effect of temperature on the fretting corrosion behaviour of tin plated copper alloy contacts in the temperature range of 25-185 degrees C, is addressed in this paper. The change in contact resistance with fretting cycles at various temperatures was determined. The contact zone after fretting corrosion test was analyzed using laser scanning microscope, X-ray diffraction (XRD), scanning electron microscopy (SEM) and X-ray spectrometry (EDX), to assess the surface profile, phase content, morphology and compositional changes across the interface. The study reveals that temperature has a greater influence on the extent of fretting corrosion of tin plated copper alloy contacts. The softening of tin is responsible for the extended region of low contact resistance observed at 85 degrees C. The increase in thickness and the resistance of Cu-Sn intermetallic compounds (IMCs) is responsible for the decrease in surface roughness and the drastic increase in the contact resistance at higher temperatures. The study suggests that the tin plated copper alloy contact system should be considered as copper alloy/IMC/Sn/SnO2 instead tin plated copper alloy. During fretting corrosion test at elevated temperatures, once the top surface layers are worn out, the contact interface is transformed from tin versus tin-to-tin-intermetallic versus tin-intermetallic. The study concludes that tin plated copper alloy contacts are not suitable for high temperature applications.
10.1016-j.wear.2006.08.025	-1		The Ni-based surface coatings were prepared by a vacuum infiltration casting technique on copper substrate. The surface coatings were fabricated through copper melt penetrating into thin preforms whose thickness could change. By optimizing the processing parameters, compact surface coatings were achievable as confirmed through SEM observation. The surface coating was mainly composed of solid solution of Ni, solid solution of Cu and CrB. The macro-hardness of the coating was about HRC 58, and the micro-hardness of the coating shows a gradient distribution. The average micro-hardness of the coating was about HV450. Wear behaviour was investigated by using block-on-ring dry sliding linear contact at several loads (50 N-300 N) and two different sliding speeds (0.424 m/s and 0.848 m/s). Wear rate and friction coefficient were estimated using a method founded upon the PV factor theory. The surface oxidation predominated as the principle wear mechanism at low load. Meanwhile, adhesion and oxidation mechanism were observed when the coatings were tested at higher load more than 200 N. Friction coefficient decreased with increasing load and sliding speed.
10.1016-j.wear.2007.01.061	16	wear; composite; composites; powders; milling; particles; powder; wt; sliding; friction; hardness; matrix; mechanical; surface; properties	\Dry sliding wear of Cu-15Ni-8Sn (in wt%) bronze against a stainless steel 440C counter surface is investigated using a pin-on-disc tester in air and flowing Ar gas. The microstructure of the debris, the worn surface and the subsurface of the pin have been characterized using X-ray diffraction, scanning electron microscopy (SEM), transmission electron microscopy (TEM), energy dispersive spectroscopy (EDS) and X-ray photoelectron spectroscopy. The debris is found to comprise of particles of Fe2O3 and CuO phases, in addition to bronze particles. EDS analysis of the debris revealed that bronze picked up Fe and Cr elements from the stainless steel while the Fe2O3 particles picked up Cu, Ni and Sri elements from the pin, attesting the mechanical mixing of chemical species during the wear process. Cross-section SEM of the worn pin revealed a highly deformed subsurface layer, capped by a thin layer separating the outer surface and the deformed layer. Cross-sectional TEM investigations of the capped layer revealed it to be a set of mechanically mixed layers (MML) comprising nanograins with varying grain size and composition. SEM micrographs also revealed the formation of subsurface cracks in the vicinity of the interface between the deformed subsurface layer and the capping layer. Wear processes are discussed in the light of these microstructural observations, combined with wear rate and friction coefficient measurements.
10.1016-j.wear.2007.03.003	-1		The wear behavior of a casting Cu-15Ni-8Sn spinodal alloy aged for different periods of time at 400 degrees C was investigated under the lubricated sliding condition at a load of 1470 N. The worn surface morphologies and debris particles were observed on a scanning electron microscope. The hardness of aged specimens of the alloy was found to increase initially with the aging time and then to decrease. The best wear resistance of the tested alloy is corresponding to the maximum value of hardness aged for 120 min. In accordance, the wear rate was inversely changed with the aging time. The friction coefficient was constant for different aging treatment. Accordingly, the wear mechanism of the alloy is discussed. Besides light abrasive wear, the dominant wear mechanism was that the surface material of the Cu-15Ni-8Sn sample was extruded by the harder asperities periodically and formed flake-like extrusions with layer structures. When these extrusions got long enough, they broke off and became the wear debris particles.
10.1016-j.wear.2007.11.004	16	wear; composite; composites; powders; milling; particles; powder; wt; sliding; friction; hardness; matrix; mechanical; surface; properties	Unlubricated fretting tests were performed with a nanocrystalline surface layer of a 99.99 wt% copper fabricated by means of surface mechanical attrition treatment (SMAT), in comparison with a coarse-grained (CG) copper. The measured friction and wear data show that the fretting wear resistance is markedly enhanced with the nanocrystalline surface layer relative to the CG counterpart. The friction coefficient and wear volume of the SMAT Cu are lower than that of the CG Cu. For both samples, the friction coefficients and wear volumes increase with an increasing applied load and fretting frequency. A rapid increase of the friction coefficient and wear volume under an applied load above a critical value (30 N for the SMAT Cu and 20 N for the CG Cu) is noticed, corresponding to the formation of a continuous oxide layer between two contact surfaces. Also two sharp increases of the friction coefficient and wear volume at fretting frequencies of 50 Hz and 175 Hz were observed for the SMAT and the CG Cu. The former is correlated with the formation of a continuous oxide layer, while the latter corresponds to wearing away of the oxide layer.
10.1016-j.wear.2008.01.023	16	wear; composite; composites; powders; milling; particles; powder; wt; sliding; friction; hardness; matrix; mechanical; surface; properties	In situ composites based on copper chromium alloys have important application in resistance welding electrodes and improvement of their mechanical and wear properties may offer better materials for similar applications. In the present investigation, mechanical and tribological properties of Cu-Cr-SiCp composites have been investigated and compared with as-received wrought copper and cast copper. The cast in situ Cu-4%Cr-4%SiC composite has a matrix of solid solution of chromium in copper, containing grayish phases of carbides such as Cr-C, Cr23C6, Cr3C7, and Cr-Si-C, as determined by X-ray diffraction analysis and optical microscopy. The cumulative volume loss of the cast composite as determined by pin-on-disk tests for dry sliding wear against hardened steel counterface, is observed to decrease to about 65% and 72%, respectively, as compared to those observed in as-received copper and cast copper at 40 N loads. The surface profile of the samples after wear test, show a significantly lower R-t and R-z in all the three materials at 20 N load. Bearing ratio curve shows that Mrl, the extent of surface which will wear out faster, has a higher value for the composites compared to that in as-received copper although the composites wear out much less because of reinforcement. Mr2, oil retaining property from the bearing ratio curves, has a fairly steady value of about 10% in cast composite after dry sliding under increasing load.
10.1016-j.wear.2008.04.029	16	wear; composite; composites; powders; milling; particles; powder; wt; sliding; friction; hardness; matrix; mechanical; surface; properties	The dry sliding wear behaviour of high volume fraction (61%) SiCp/Cu composite produced by pressureless infiltration was studied with a pin-on-disc system. The wear tests were carried out under an applied load from 50 N to 200 N and sliding speed of 1.3 m/s and 2.6 m/s. The results indicate that the volume loss increases with applied load, sliding speed and sliding distance. The wear resistance of the composites containing larger reinforcement is higher than those of the composites with smaller particles due to the enlargement of the mean free path between particles. The main wear mechanisms are abrasive wear and oxidative wear. The mechanically mixed layer (MML) controls greatly the wear rate and friction coefficient of the composites. The composites tested at high sliding speed exhibit high value of friction coefficient and intense fluctuation, which is associated with the intermittent formation and removal of the MML High reinforcement content, small size ratio of abrasive size to reinforcement size and strong interfacial bond are all contribute to the excellent wear resistance of SiCp/Cu composites.
10.1016-j.wear.2009.06.026	16	wear; composite; composites; powders; milling; particles; powder; wt; sliding; friction; hardness; matrix; mechanical; surface; properties	A new type Cu-La2O3 composite was fabricated by internal oxidation method using powder metallurgy. Sliding wear behavior of the Cu-La2O3 composites was studied by using a pin-on-disk wear tester under dry sliding conditions with or without electrical current, rubbing against GCr15 type bearing steel disk at a constant sliding speed of 20 m/s. The influence of varying applied load and electrical current was investigated. The worn surfaces were examined using scanning electron microscopy (SEM) and energy dispersive spectroscopy (EDS) to determine the wear mechanisms. The results showed the Cu-La2O3 composites had an electrical conductivity of 81.9% IACS (International Annealed Copper Standard, 100% IACS = 58 MS/m) and a hardness of HV105. The wear rate of the Cu-La2O3 composite pins increased with the increase in the electrical current at high sliding speed. The main wear mechanisms of the Cu-La2O3 composites were found to be adhesive wear, abrasive wear and arc erosion.
10.1016-j.wear.2010.04.026	16	wear; composite; composites; powders; milling; particles; powder; wt; sliding; friction; hardness; matrix; mechanical; surface; properties	W-25 wt%Cu nanocomposite powder was prepared by thermochemical co-precipitation method. Consolidation procedure was performed at 1200 degrees C under hydrogen atmosphere and led to the densification up to 98% theoretical density Wear test was carried out with a pin-on-disc apparatus under 5, 10, and 15 N normal loads. Volume of the lost material and also the wear rate increased by increasing the normal load while, friction coefficient showed a reverse record and decreased by increasing the load. Formation of mechanically mixed layers (MMLs) and their successive deformation and work hardening was found to be the origin of the friction coefficient decrease at increased normal loads. At low normal load just shallow scuffs and particle pull out were observed in the surface and sub-surface studies of the wear sample. But at higher normal loads large flakes of the matter were cut off and lost accompanying deep grooves and branched cracks. Continuous cyclic deformation at sufficiently high normal loads, could give rise to MML formation, sub-surface deformation, crack nucleation and propagation, and finally delamination of the composite
10.1016-j.wear.2010.12.052	-1		Recently friction and wear of copper (Cu) samples (the average grain size, d = 30 mu m) rubbed against a hardened steel in steady friction were studied. The effects of load and sliding velocity were interpreted by the Stribeck curve and the transitions from elasto-hydrodynamic lubrication (EHL) to boundary lubrication (BL) region were analyzed. It was shown that the wear rate is proportional to a load both in the EHL and in the BL regions. The hardness of thin surface layers saturates during repeating sliding of Cu that is close to the hardness of nanocrystalline Cu produced by different severe plastic deformation (SPD) processes. The present investigation was initiated with three objectives similar to our previous works with the Cu samples: first, to study the friction and wear behavior of Cu surfaces with different grain sizes under different lubricant conditions; secondly, to examine the structural evolution of Cu subsurface layers under friction in different contact conditions and thirdly, to evaluate the effect of grain refinement by equal channel angular pressing(ECAP) on friction and wear. The Stribeck curves for the Cu-steel pairs with different virgin grain sizes of Cu (d = 1 mu m. 30 mu m and 60 mu m) are presented. All Stribeck curves have the similar shape and only shifted depending strongly on virgin hardness of the Cu samples. The transitions from one lubricant region to another depend on the virgin grain size. The lesser the grain size of Cu, severe the condition of transition to BL region. Grain refinement by ECAP (d = 1 mu m) shifts the Stribeck curve in the range of severe contact conditions (high loads and low sliding velocities). Preliminary severe plastic deformation of Cu samples leads to remarkable decreasing the wear loss in comparison to coarse grain size samples. The hardness of thin surface layers (similar to 1 mu m) saturates during repeating sliding of Cu and this value is close to the hardness of nanocrystalline Cu produced by different SPD processes. Since plastic deformation and wear occur in ML and BL regions, the known lubrication numbers cannot be used for description of the transitions to these lubrication regions. New parameter, K, as the ratio between the hardness values of tested and annealed samples is introduced in lubrication number in order to take into account the effect of grain size on friction and wear in different contact conditions. Application of K allows a prediction the effect of grain size on the transitions from one lubrication region to another.
10.1016-j.wear.2010.12.063	-1		A simple surface nanocrystallization process combining repeated hammering and recovery treatment was applied to Cu-30Ni alloy for improved resistance to corrosive wear in a NaCl solution. This study was motivated by aquaculture applications of copper alloys, which require not only the resistance to pure corrosion but also that to corrosion involving wear such as scratching. The synergy of corrosion and wear may significantly accelerate surface failure of copper alloys in the marine environment. We nanocrystallized the surface of the copper alloy by repeatedly hammering the surface followed by a recovery treatment that turned dislocation cells into nano-sized grains, which considerably strengthened the surface. The high-density grain boundaries largely enhanced atomic diffusion and thus improved the passivation capability of the nanocrystallized surface. As a result, the nanocrystallized surface possessed higher resistances to corrosion, wear and corrosive wear. In this work, particular emphases were put on effects of the hammering duration on the thickness of nanocrystallized surface layer and variations in corrosion, wear and corrosive wear rates as a function of the distance from top surface to bulk Variations in other relevant properties with the distance were also investigated, including the adhesive force, friction coefficient and hardness. The relationships between the properties and depth help to estimate the durability or service life of the nanocrystallized surface layer. Efforts were made to clarify the mechanisms responsible for observed phenomena and relationships.
10.1016-j.wear.2011.08.023	16	wear; composite; composites; powders; milling; particles; powder; wt; sliding; friction; hardness; matrix; mechanical; surface; properties	A new method is proposed to explain and monitor wear behaviour based on energy dissipation. The wear of a W-25 wt%Cu composite against 52100 steel was used to demonstrate this approach with pin-on-disc tests conducted under three normal loads. An energy-dependent criterion, namely, specific wear volume (wear volume/dissipated energy (mm(3)/J)), was defined to evaluate the wear of the composite. The specific wear volume can be used as a substitute for the traditional wear rate due to the simultaneous expression of several wear parameters and because of its strong dependence on the wear mode. The specific wear volume appears to be constant in any particular wear mode regardless of the active wear processes. In the wear of this composite, processes such as particle pull-out, mechanically mixed layer (MML) formation, crack propagation and delamination were observed. But, combination of these processes in each test had identical specific wear volumes. Thus, all of these wear processes were considered to be consecutive stages of the same wear mode: fatigue wear. The amount of dissipated energy and the volumetric loss increased with increasing normal load. Also, changing the normal load changed the rate of energy dissipation per unit sliding distance.
10.1016-j.wear.2012.04.006	-1		In this paper, the effect of pv factor on the tribological behavior of a copper-impregnated metallized carbon brush sliding against a Cu-Cr-Zr ring was investigated. Friction and wear tests were conducted on a brush-on-slip ring type wear tester. The tests were performed at two electrical currents (0 and 20 A) and seven different combinations of contact pressure (p) and sliding velocity (v), herein referred to as the pv factor to study the relationship between electrical and mechanical wear. The results show that mechanical wear aggravates electrical wear. Higher interfacial temperatures appear to be responsible for the higher wear rate. Worn surfaces of brush specimens were observed and analyzed by scanning electron microscope (SEM) and energy dispersive X-ray analysis (EDS). It is apparent that the degree of tribo-oxidation at the brush increases with an increase in pv, which has a significant influence on the tribological behavior of the brush specimen.
10.1016-j.wear.2012.05.001	-1		Under certain conditions, the metals of some heavily loaded tribological units may slide against each other without the benefit of lubrication. In such cases, the heat or electrical conduction properties of the sliding materials are particularly important. Copper-based materials are relevant for such application. In this study, we investigated the wear and friction that occurs between copper-based composites and copper under dry sliding conditions. We varied the composition levels of molybdenum disulfide and molybdenum diselenite (from 1 to 15 percent) that were incorporated into a Cu-based substrate. The specimen composition (Cu + 1; 5; 10 and 15 wt% MoS2 and MoSe2) was prepared by sintering powders with an average particle size of 35-40 mu m into a hydrogen atmosphere at a temperature of 780 degrees C for 2 h . Pin-on-disk experiments were performed without any lubrication at a speed of 0.15 m/s while maintaining a contact pressure of 0.127-1 MPa. The prepared samples were used as flat-ended pins and slid against a copper plate to ensure contact conformability. The reference copper rapidly began scuffing and eventually experienced a catastrophic failure of the contact surfaces after a relatively short period of smooth sliding. Scuffing and catastrophic damage was prevented by using powder metallurgy technology to incorporate MoS2 and MoSe2 into the copper. Materials with MoS2 and MoSe2 had a coefficient of friction close to 0.2, undetectable linear wear under a contact pressure of less than 0.255 MPa, and an absence of material transfer between the pin and the copper plate. The solid lubricant embedded in the composite materials disintegrated and lubricated the surfaces; however, a protective layer did not form on the counterface. Heavier loads initiated substantial wear. Material removal resulted from adhesion between the sliding composite materials and the transferred material on the Cu counterface, which forms flaky debris. The mechanism of wear of the composite materials Cu-MoS2 and Cu-MoSe2 is consistent with the material removal process. As a function of composition, the lubricating effect is more pronounced at concentrations greater than 5 wt% of the solid lubricant.
10.1016-j.wear.2013.01.062	16	wear; composite; composites; powders; milling; particles; powder; wt; sliding; friction; hardness; matrix; mechanical; surface; properties	Copper-chrome-zirconium (Cu-Cr-Zr) alloys can be used in the optics industry to make mould inserts for injection of thermoplastic optical parts such as lenses and windows. The fabrication of optical mould inserts is usually achieved by diamond turning in order to obtain necessary optical surface finish and high form accuracy. This study was undertaken to investigate the tool wear characteristics when ultra-high precision machining of Cu-Cr-Zr with mono-crystalline diamond inserts. In this work, standard non-controlled waviness diamond inserts having nose radius of about 1.5 mm, rake angle of negative 5 degrees, clearance angle of 5 degrees and included angle of 60 degrees were used to produce a flat mirror of 50-mm diameter. Wear patterns occurring on the tool flank and rake faces were observed. Diamond tool performance is discussed in terms of possible wear mechanisms. In addition, the tool wear is associated with the acoustic signals emitted during machining. The preliminary results from the SEM analysis show that abrasive wear is a dominant mechanism especially at low feed rates. The study yields some recommendations on the best combination of machining parameters that will result in maximum material removal rates with relatively smallest possible damage to the tool edge.
10.1016-j.wear.2013.04.006	-1		Dry sliding wear behavior of nanostructured eutectic Ag-Cu with grain size similar to 114 nm was investigated using pin-on-disc testing. The subsurface microstructure and texture evolution were characterized by X-ray diffraction, scanning electron microscopy, transmission electron microscopy, nano-beam diffraction, and high angle annular dark field. During sliding wear, plastic deformation transforms the subsurface material into hierarchical microstructures. At depths of 1-15 mu m below the sliding surface, a two phase (Ag-rich and Cu-rich) nano-lamellar structure is observed, where the layer thickness decreases from 98 nm at a depth of 15 mu m to 11 nm at a depth of 1 mu m. Right below the sliding surface, where an equivalent strain of 7.1 was estimated, wear induced plastic deformation drives the subsurface material into a non-equilibrium super-saturated solid solution phase, with similar to 9 nm equiaxed nano-grains. These refined microstructures led to significant work-hardening in the subsurface material, as revealed by nanoindentation testing. Finally, the microstructure evolution and the underlying deformation mechanism of Ag-Cu are discussed on the basis of these characterizations.
10.1016-j.wear.2013.05.013	-1		The aim of this work is to evaluate the strengthening and damage of surface layers of copper (Cu) after friction in different lubricant regions and to compare them with stress strain properties of Cu refined by different methods of severe plastic deformation (SPD). Friction and wear tests were performed using a ring-on block rig. The structure and damage of Cu samples rubbed in Elastic Hydrodynamic Lubrication (EHL) and Boundary Lubrication (BL) were studied. It was shown that the formation of the laminar structure in surface layers under friction in the EHL region is accompanied by a generation of pores and their coalescence. The calculated value of the strain rate during friction in the EHL region was compared with the Coble creep and grain boundary sliding models. It was found out that the deformation hardening, nanocrystalline grain size and level of plastic deformation of thin surface layers under friction in the BL region are close to the parameters of refined structure of Cu obtained by different methods of SPD. Friction saturation in the EHL and BL regions is considered to be a result of the dynamic recovery based on thermally activated processes of accumulation and annihilations of dislocations. The relation between the dislocation accumulation and dynamic recovery determines the transition from one contact region to another. Constant values of the hardness, grain size and geometrical parameters of contact at the steady friction state in different lubricant regions indicate any connection between the structural and geometrical parameters of contact.
10.1016-j.wear.2014.01.001	17	wear; composites; coating; friction; composite; coatings; surface; tribological; properties; wear resistance; resistance; powder; sliding; matrix; wear rate	Using 2.5-dimensional carbon fibre fabric as the reinforcement, carbon/carbon-copper (C/C-Cu) composites were prepared by a combination of impregnation-carbonisation (I/C) with furan resin and melt Cu alloy infiltration under pressure. The effect of heat treatment temperature for porous carbon/carbon composites (C/C substrates) on the structure and sliding wear behaviour of C/C-Cu composites under an electric current was investigated. The results show that heat treatment temperature has great influence on the structure, graphitisation degree and sliding wear behaviour of C/C-Cu composites. With the increase of heat treatment temperature, wear rates of C/C-Cu composites decrease first and then increase. The composites treated at 2573 K have the lowest wear rates of 36.60 mm/10,000 km and 22.80 g/10,000 km, which is about half of those of Cu-graphite composites now used in high-speed railways. In addition, the main wear mechanisms were abrasive wear and arc erosion.
10.1016-j.wear.2014.01.007	-1		The effect of an ultrafine-grained (UFG) microstructure and subsequent aging treatment on the mechanical and wear behavior of a Cu-Cr-Zr alloy was investigated. The results indicate that the precipitates dispersed within the UFG matrix significantly enhance the strain hardening, resulting in improvement of hardness, strength and wear resistance of the alloy, without notably sacrificing the elongation to failure and electrical conductivity, due to the combined effect of grain refinement and precipitation. The wear behavior of Cu-Cr-Zr alloy was found to be strongly dependent on its strength and hardness. The minimum weight loss (or the highest wear resistance) was obtained when the sample was processed by equal channel angular extrusion (ECAE) through an additional aging treatment, as this resulted in ultra-high strength and hardness. The wear results also indicate that the wear behavior of Cu-Cr-Zr alloy in all processing conditions is consistent with the Archard approach . Complex wear mechanisms such as adhesive, oxidative and abrasive wear, and delamination were found to be operative in the differently processed Cu-Cr-Zr alloys. It is to be concluded that the use of a two-step process, the first resulting in an UFG microstructure and a subsequent aging treatment provides a simple and effective procedure for extraordinary increase in strength, hardness and wear resistance of Cu-Cr-Zr alloys without modification of the chemical composition.
10.1016-j.wear.2014.07.014	-1		The retention of the desired combination of mechanical/tribological properties in ultrafine grained materials presents important challenges in the field of bulk metallic composites. In order to address this aspect, the present work demonstrates how one can achieve a good combination of hardness and wear resistance in Cu-Pb-TiB2 composites, consolidated by spark plasma sintering at low temperatures ( < 500 degrees C). Transmission electron microscope (TEM) studies reveal ultrafine grains of Cu (100-400 nm) with coarser TiB2 particles (1-2 mu m) along with fine scale Pb dispersoid at triple junctions or at the grain boundaries of Cu. Importantly, a high hardness of around 2.2 GPa and relative density of close to 90% relative density (rho(theo)) have been achieved for Cu-15 wt% TiB2-10 wt% Pb composite. Such property theo, combination has never been reported for any Cu-based nanocomposite, by conventional processing route. In reference to the tribological performance, fretting wear tests were conducted on the sintered nanocomposites and a good combination of steady state COF (0.6-0.7) and wear rate (10-4 mm(3)/N m) were measured. An inverse relationship between wear rate and hardness was recorded and this commensurates well with Archard's relationship of abrasive wear. The formation of a wear-resistant delaminated tribolayer consisting of TiB2 particles and ultrafine oxide debris, (Cu, Fe, Ti)(x)O-y as confirmed from subsurface imaging using focused ion beam microscopy has been identified as the key factors for the low wear rate of these composites.
10.1016-j.wear.2014.08.016	-1		Friction, wear and plastic deformation of copper (Cu) and alpha/beta brass were studied under lubrication conditions. Hardness and microstructure of surface layers were evaluated. The friction properties were presented by Stribeck curves. The friction coefficient and wear of brass were significantly larger in comparison to Cu. The critical load of transition from the elasto-hydrodynamic lubrication (EHL) to boundary lubrication (BL) was two times lower for brass. Superplastic deformation of alpha-phase grains in brass is appeared under friction in BL, whereas plastic deformation localized at thin surface layers is observed for Cu. lntragranular sliding in (C-phase is accompanied with the formation of shear bands and many pores coalesced to cracks. Thickness of the wear particles of brass is close to the width of shear bands. The deformation hardness of brass is significantly higher in comparison to Cu rubbed in the BL region. (C) 2014 Elsevier B.V. All rights reservecl
10.1016-j.wear.2015.10.016	-1		Friction between copper-zinc (brass) alloys and uncoated as well as differently coated carbide tools was investigated by using a recently developed friction test, characterized by high contact forces, temperatures, and relative velocities. The major aim was to analyze the ability of various tool-brass combinations for reducing friction, adhesion and thus tool wear in cutting operations and to understand the existent mechanisms of action. In the first part of the study, the friction conditions between low-leaded brass alloys with varying chemical composition (CuZn38As, CuZn42 and CuZn21Si3P) and uncoated as well as TiB2 and DLC (ta-C) coated carbide tools were analyzed and compared to the high-leaded free-cutting brass CuZn39Pb3. In a second step, materials with almost the same chemical composition were used (CuZn41.5). Hereby, the influence of low lead contents ranging from Pb=0.003-0.19% on friction, was analyzed and compared to a high lead content of Pb=1.9%. It can be summarized that significant differences in frictional behavior were determined depending on the material's chemical composition, microstructure, mechanical properties, lead content, tool coating and relative velocity. Regarding the applied tools, the lowest coefficients of friction and process temperatures were detected when using a DLC (ta-C) coating.
10.1016-j.wear.2016.01.023	-1		Historically, copper (Cu) and its alloys have played a vital role as additives to non-asbestos friction materials (FMs). Their main functions include; to increase thermal conductivity, to act as a solid lubricant at high temperature, and to influence general tribological performance. Environmental concerns in most of the advanced countries have resulted in legislation to gradually phase out the use of Cu in FMs. Thus, the FM Industry is facing a challenge to replace Cu and its alloys in FMs with additives that will match the desired performance. The goal of this work was to test the potential of two new FM fillers (conductive rock-fibers and thermo-graphite-TG) on a brake dynamometer using standard test schedule (JASO 406). Five brake-pad materials, comprising two series, were developed with identical parent compositions. The first series called Copper Based (CB) consisted of two FMs with and without untreated Rockwool (RB) and natural graphite (NG). The second series designated as Copper-Free (CF) series contained three FMs with increasing wt% of rock fibers (10%, 15% and 20%), along with 10% TG. Physical and mechanical properties of the compression-molded pads were measured. Cu-based FM performed better than the Cu-free FMs, but not significantly in most of the important properties. For certain other properties, Cu-free FMs performed better.
10.1016-j.wear.2016.11.050	16	wear; composite; composites; powders; milling; particles; powder; wt; sliding; friction; hardness; matrix; mechanical; surface; properties	Aim of the work is to investigate the tribological behaviour of Cu based materials produced by mechanical milling (MM), mechanical alloying (MA) and finally sintered by Spark Plasma Sintering (SPS). MM causes a significant strain hardening of Cu, while MA by 0.5 wt%TiB2 adds a further dispersion hardening contribution. During dry sliding contact against high speed steel a close relation has been found between friction coefficient and contact temperature highlighting two regimes. The first one, occurring at an early stage of the process, is characterized by a high friction coefficient (similar to 1), typical of the strong adhesion of Cu-Cu contact. The second one is characterized by a lower steady-state friction (similar to 0.7) related to the change of wear mechanism from adhesive metallic into triboxidative. By increasing the load the friction coefficient decreases, the transition time from the adhesive to triboxidative friction regime decreases and the contact temperature increases. Under abrasive wear conditions the penetration depth of the indenter is progressively reduced by increasing hardness, highlighting the benefits of MM and, even more, of MA. The Cu+0.5 wt%TiB2 composite alloyed for 240 min shows the best wear resistance under both wear conditions. The good wear resistance combined to high thermal conductivity represent very attractive properties for many applications.
10.1016-j.wear.2016.12.041	17	wear; composites; coating; friction; composite; coatings; surface; tribological; properties; wear resistance; resistance; powder; sliding; matrix; wear rate	Several experimental tests are conducted on a high-speed block-on-ring tester to study friction and wear behaviours of a Cu Ag contact wire and a pure copper contact wire rubbing against a carbon strip with electric current. The test parameters are set as follows: electric current 0-250 A, sliding speed 110-170 km/h and normal load 50-130 N. The friction coefficient, wear volume and arc discharge energy are analyzed. The experimental results show that the friction coefficient of the carbon strip/Cu Ag alloy contact wire is larger than that of the carbon strip/pure copper contact wire, and that the wear rate of the carbon strip which rubbed against the Cu Ag alloy contact wire is larger than that of the carbon strip which rubbed against the pure copper contact wire. Discussion is presented to explain the friction and wear behaviours.
10.1016-j.wear.2017.09.016	-1		In this work, TiB2 particulate reinforced copper matrix composites were fabricated by casting method, based on in situ precipitation reaction between B and Ti elements to form TiB2 particles in molten copper. The microstructures of the Cu-TiB2 composites were characterized using SEM and TEM. The results show that TiB2 particles are successfully formed in the copper matrix and the interfaces between these particles and the matrix are clean and well bonded. The friction and wear characteristics of the Cu-TiB2 composites were determined by carrying out dry sliding tests on pin-on-disk machine under varying loads, sliding speeds and sliding distances. A comparison between the volume wear losses of the composites under different conditions shows a significant improvement in wear property of the composites with respect to the pure copper. Furthermore, the mechanical properties of the composites with different TiB2 levels were also investigated. Both tensile strength and hardness are significantly improved with the increasing amount of TiB2 in copper matrix, while compromises of the elongation and electrical conductivity nevertheless occur in all cases.
10.1016-j.wear.2018.01.013	-1		To explore the W nanoparticles effects on the subsurface microstructural self-organization of Cu-Ag two-phase alloys and the resulting wear performance, we have fabricated bulk nanostructured Cu-10 at% Ag-10 at% W ternary alloys by high energy ball milling and warm pressing. During ball milling, Ag is dissolved into the Cu matrix but W remains immiscible. Compaction of the powders into bulk at 300 degrees C leads to the Ag precipitation. The as-pressed Cu-10 at% Ag-10 at% W ternary alloy has Ag-rich precipitates size (d(Ag)) of 22 nm and W particles size (d(w)) of 26 nm. Further annealing at 600 degrees C for 1 h only increases d(Ag) and d(w) to 52 nm and 41 nm, respectively. The fabricated Cu-10 at% Ag-10 at% W ternary alloys thus demonstrate enhanced coarsening resistance. The two alloys were then subjected to dry sliding wear against stainless steel disks. It is found that the initial length scale of Ag-rich precipitates and W particles has a profound influence on the microstructure evolution during wear and accordingly on the wear performance. For the as-pressed sample with small d(Ag) and d(W), severe plastic deformation (SPD) by wear forced the formation of Cu-Ag homogeneous solid solution, leading to low wear resistance. In contrast, for the annealed one with relatively large d(Ag) and d(W), the Cu, Ag and W three phases co-existed but the Ag-rich precipitates were transformed into wavy nanolayers, providing enhanced wear resistance. Compared with Cu-Ag alloys subjected to sliding wear, the presence of W nanoparticles was found to hinder the formation of self-organized nanolayered structure and leads to a small deformation depth . The obtained results provide deep insights into the plastic deformation mechanisms in ternary alloys and the design of wear resistant engineering materials.
10.1016-j.wear.2018.12.075	-1		To form the individual elements, that together form a zipper, a pre-formed Cu-alloy wire is sheared using cemented carbide tools. The wear caused by the relatively soft copper alloy on the much harder tool is generally quite slow. However, millions of elements are to be sheared so eventually the wear becomes unacceptable and the tool needs to be exchanged. To improve product quality, as well as minimize down time and material consumption, the tool life needs to be prolonged. To achieve this the wear process needs to be better understood. Uncoated tools used for an increasing number of shearing events have been studied in detail using high resolution SEM and EDS, to map the propagating wear and get an insight into the wear mechanisms. Transfer of material from the Cu-alloy to the tool occurs and the wear is highly concentrated to specific areas. This wear occurs on a very fine scale, limited to within individual WC grains at each event. Tools coated with PVD CrC and PVD CrN have been studied for comparison with the uncoated cemented carbide. Both coatings successfully protect the cemented carbide tool from wear, however occasional flaking occurs and then the cemented carbide becomes exposed and subsequently worn. The differences in performance and wear mechanisms between the uncoated and coated tools are discussed, with focus on the capability of the coatings to prolong the tool life.
10.1016-j.wear.2019.203102	-1		Cu-Al-Fe aluminium bronze alloys are good candidates for precious tools and forming dies due to their high wear resistance, good sliding properties and low tendency for adhesion to ferrous metals. Plasma transferred arc (PTA) is an effective process for deposition of such robust coatings by enhancing the bond between the bronze coating and steel substrate. However, the microstructure and wear characteristics of these coatings are strongly influenced by the diffusion of substrate elements (mostly iron) to the interface. In the present study, the effects of substrate dilution on the microstructure and wear behaviour of Cu-Al-Fe alloy deposited by PTA on medium carbon steel substrate were investigated. The results show that the deposition current controls the melting temperature and iron dilution which result in the formation of Cu3Al martensitic beta(1)' phase in a low dilution and the ordered beta(1) phase in high dilution. The wear behaviour of the coating is dominated by failure of the matrix phase. Low dilution coating with martensitic phase exhibits the highest wear resistance. On high diluted Fe rich coating, pile up of dislocation on the intermetallic K phase leads to surface cracks and delamination of the coating resulting in a high wear rate.
10.1016-j.wear.2019.203156	-1		The purpose of this research was to investigate the potential use of Cu-Ti3AlC2 composites sliding against a Cu-5%Ag alloy as a viable electrical contact couple. Sliding friction and wear tests were conducted in the presence of an electric current using a custom-designed block-on-ring wear testing apparatus. The electrical current density was 0-15 A/cm(2) along with an apparent contact pressure of 1.25-7.5 N/cm(2) and sliding velocities ranging from 2.5 to 15 m/s. The results indicate that friction coefficient, wear rate, and contact voltage drop measured for the sliding couple increases with an increase in the electrical current density. As the apparent contact pressure increases, the contact voltage drop of Cu-Ti3AlC2 composites increases gradually, while friction coefficient and wear rate first decrease and then increase. With an increase in the sliding velocity, the friction coefficient of the sliding pair decreases and the contact voltage drop increases gradually, while wear rate decreases first, then increases. Adhesive wear and arc erosion wear proposed as the main wear modes. A lubricating film was observed to form on the wear surfaces under each test condition, and that film apparently improves the tribological properties of the sliding couples.
10.1016-j.wear.2020.203260	16	wear; composite; composites; powders; milling; particles; powder; wt; sliding; friction; hardness; matrix; mechanical; surface; properties	The effect of ZrB2 (1, 3, 5, 10 wt%) reinforcement on two-body abrasion wear properties of Cu was studied using pin-on-disc wear tester. The relative density of Cu-ZrB2 composites varied in the range between 96.0 and 99.7%, and in particular, relative density of copper was lowered with the addition of ZrB2. Among all the composites, Cu-10ZrB(2) showed maximum hardness (1.25 GPa) and yield strength (261 MPa). However, the improvement of mechanical properties of Cu with ZrB(2 )was marginal. On the other hand, the ZrB2 addition significantly affected the wear properties of Cu. The steady-state coefficient of friction (COF) of Cu was reduced from 0.56 to 0.16 with the addition of ZrB2. Pure Cu exhibited a high wear coefficient (17.33 x 10(-2)) due to its softness and high ductile nature. The abrasive wear resistance of Cu was considerably improved with the addition of ZrB2 (up to 3 wt%) by resisting the cutting forces of SiC abrasives (counterbody). A low wear coefficient of 2.4 x 10(-2) was evident for Cu-3ZrB(2) composites and the wear was reduced by 7.33 times compared to pure Cu. Further addition of ZrB2 reinforcement lowered wear resistance of Cu composites. Nevertheless, the wear resistance of Cu composites was substantially better than pure Cu. The wear mechanisms were proposed based on microstructural analysis of worn surfaces of Cu-ZrB2 composites, SiC emery paper (counterbody) and wear debris. The present study demonstrates the advantage of selecting ZrB2 as reinforcement in improving the abrasion wear resistance of Cu.
10.1016-j.wear.2020.203474	16	wear; composite; composites; powders; milling; particles; powder; wt; sliding; friction; hardness; matrix; mechanical; surface; properties	Cu-15 wt%Ni-8 wt%Sn (CuNiSn) bronze alloy shows promising bearing performance when used in tribological applications and has attracted increasing research interest. In this work, the tribological performance of CuNiSn in terms of friction and wear were investigated in a ball-on-disc contact configuration, sliding against a Al2O3 ball under varying normal loads (1 and 4 N) and environmental temperatures (room temperature (similar to 18 degrees C) and 110 degrees C). Post-test characterization techniques, including optical profilometry, scanning electron microscopy (SEM), energy dispersive X-ray (EDX) and transmission electron microscopy (TEM) were adopted to characterize the wear track on the CuNiSn surface after 13,500 cycles of reciprocating sliding. Both friction and wear behaviour was found to depend on the load and temperature whilst wear resistance reduced with increased temperature. A mechanically mixed layer (MML) and plastic deformation layer (PDL) were characterized by TEM micrographs of the cross-section from the wear track. Under 4 N load, a 1-1.5 mu m thick tribolayer was developed during sliding at room temperature compared with a 200-300 nm tribolayer at 110 degrees C. The friction and wear mechanisms were largely dominated by properties of the tribolayers which were initially associated with and affected by load and temperature.
10.1016-j.wear.2020.203487	-1		In the manufacturing of metal zippers, including several complicated forming and shearing process steps, the tool wear is a limiting factor, since it deteriorates the quality of the zipper elements. Hence, an increased understanding of the tool wear mechanisms occurring in the zipper production is important to prolong the tool life. To gain deeper insights into the tool wear mechanisms active in the process of shearing Cu alloy wire into separate zipper elements, the present study utilizes a simplified sliding test rig. The rig comprises a small tool material cylinder sliding against a large rotating work material cylinder, in a crossed cylinders configuration. One uncoated and two PVD-coated cemented carbide cylinders were tested under contact conditions similar to those of the actual shearing. The tool material cylinder was analyzed by scanning electron microscopy (SEM) and energy dispersive X-ray spectroscopy (EDS) at selected intervals during the test. The surface appearance was investigated and compared with observations on tools used in actual zipper production. The degradation was found to include gradual wear against the Cu alloy, transfer of the Cu alloy and characteristic modifications of the topography, indicative of wear mechanisms operating at a very small scale, confirming that the wear of the shearing tools can be mimicked by the test.
10.1016-j.wear.2020.203497	16	wear; composite; composites; powders; milling; particles; powder; wt; sliding; friction; hardness; matrix; mechanical; surface; properties	The fretting wear behavior of copper-magnesium alloy (Cu-Mg alloy) used for high-speed railway catenary system was investigated. Fretting tests of Cu-Mg alloy cylinder against Cu-Mg alloy cylinder at vertical cross contact configuration were carried out on a fretting wear rig at room temperature. The running condition fretting map (RCFM) composed of partial slip regime (PSR), gross slip regime (GSR), and mixed fretting regime (MFR) was constructed depending on different normal loads and displacement amplitudes. In PSR, only slight surface damage was detected on the wear scar. In MFR, the morphologies of the wear scar displayed a clear subdivision in the central stick zone and the surrounding annular slip zone. Fatigue cracks initiated and propagated at the boundary between the stick zone and slip zone. The damage mechanism is the combination of fretting fatigue and fretting wear which combines adhesion, surface fatigue and slight tribochemical reactions. In GSR, fretting wear is predominant. The wear mechanisms were mainly abrasion, surface fatigue and severe tribochemical reactions dominated by oxidation.
10.1016-j.wear.2020.203521	-1		During reciprocating sliding of the Cu and Cu-Al alloys, we found that the characteristics of subsurface morphological patterns are intimately linked to dynamic recrystallization (DRX) structure generated by sliding. With the decreasing DRX grain size, the pattern changes from vortical to laminar feature at about 0.5 mu m. The reciprocating sliding motion is favorable for producing morphologically vortical pattern and the DRX structure, while the occurrence of these processes is rare under unidirectional sliding. Additionally, the samples under unidirectional sliding exhibit higher wear resistance than those under reciprocating sliding, which may facilitate the development of delaminating tribolayer. The present results shed new insight into the relationship between morphological pattern, microstructure and wear behavior of materials under different sliding modes.
10.1016-j.wear.2020.203589	-1		Cemented carbide tools are successfully used to shear Cu alloy wire into zipper elements in the zipper industry. However, wear of the tools is the limiting factor for the production rate and the industry would benefit from more wear resistant tools. Previous investigations have indicated that the wear is tribochemical, and to investigate the role of Zn in commonly used Cu alloy testing is repeated against pure Cu in this work. The tool material used is a cemented carbide, in uncoated, CrC coated and CrN coated versions. The tests are performed in a simplified sliding test rig, combined with intermittent scanning electron microscopy (SEM) and energy dispersive X-ray spectroscopy (EDS) analysis. The tools are gradually worn and Cu is adhered and transferred to all tool surfaces. This process results in a pattern consisting of ridges and valleys on uncoated cemented carbide and CrC. Both are worn significantly faster than CrN, where much of the original surface roughness still remains after the full test. These worn surfaces are similar to the corresponding surfaces worn against the previously tested Cu-Zn alloy. However, the wear rate is dramatically higher in the pure Cu tests.
10.1016-j.wear.2021.203667	16	wear; composite; composites; powders; milling; particles; powder; wt; sliding; friction; hardness; matrix; mechanical; surface; properties	Cu-Ni alloys are thermally and chemically operationally stable alloys. Even though its wear resistance is superior to that of its pure metal components, the addition of reinforcing phases can further improve the wear behaviour of the alloys in an attempt to develop lighter materials resistant to degradation by corrosion and wear. The dry sliding wear behaviour of Cu10Ni matrix composites reinforced with 55 vol% TiC particles was investigated in an experimental pin-on-ring arrangement with a AISI M2 hardened steel ring as a counterpart at normal loads of 25 N, 52 N and 103 N, and sliding velocities of 0.3 m/s, 0.6 m/s and 0.8 m/s. The worn surfaces and wear debris were characterized by scanning electron microscopy (SEM), energy-dispersive spectroscopy (SEM-EDS) and x-ray diffraction (XRD) techniques. The infiltrated composites had less than 1.8% porosity. The Cu10Ni alloy exhibited significant material displacement towards the wear track margin and a highly deformed subsurface up to more than 200 mu m deep. Despite the higher wear rate of the unreinforced alloy, the coefficient of friction (COF) of Cu10Ni was lower because of the hard-particles exposed in the surface of the composites. The dominant wear mechanism of the alloy was adhesive and oxidative wear. In the least case, the TiC/Cu10Ni composite has three times more wear resistance than the pure Cu10Ni matrix. The wear behaviour of the composite is characterized by a tribochemical reaction that involves oxidation of the matrix and transferred material forming protective tribolayers through an additional sliding process. The surface consists of numerous simple and mixed oxides of Fe, Cu and Ni. The highest rate of composite wear was achieved in the combination of maximum sliding velocity and higher applied load. The mechanism that governs the wear process in composites combines abrasive, adhesive and oxidative wear.
10.1016-j.wear.2021.203681	-1		Sliding wear damage to non-lubricated metallic bearing surfaces results from the dissipation of frictional work. Damage features at or near worn surfaces depend on alloy-specific modes of deformation that are influenced by stacking fault energy (SFE) and other microstructural properties. Metal pairs having similar friction coefficients do not necessarily wear equally due to differences in energy partition. Dissipative mechanisms include highlydeformed layer (HDL) formation, deformation twinning, recrystallization, amorphization, and texturing. In some tribosystems, a portion of the frictional work is dissipated in third-body layers. HDL thickness can vary from grain-to-grain, depending on crystallographic orientation relative to the sliding direction. Thus, the energy used in texturing can also vary grain-by-grain. Composition and surface processing methods affect the manner and degree of friction/wear correlation. Transitions in wear mechanisms are investigated in a series of Cu-Al binary alloys ranging from 0 to 15 wt% Al that are processed by different routes. These bronzes were worn against bearing steels in a non-lubricated block-on-ring configuration. Application of established and less common imaging methods supports the transition from sharpened dislocation cell formation at higher SFE to deformation twinning at lower SFE. At the wear process level, primary and secondary wear debris affect model development because their relative influence changes over time.
10.1016-j.wear.2021.203793	16	wear; composite; composites; powders; milling; particles; powder; wt; sliding; friction; hardness; matrix; mechanical; surface; properties	A composite of interest for high-temperature applications, where high thermal conductivity, dimensional stability, and wear resistance are required, is the Cu/TiC-Graphite hybrid system. The wear behaviour of three different composites with a graphite volume of 1%, 3% and 5% was investigated, for a total volume of 60% of reinforcement, in a pin-on-disc arrangement with a steel sphere counterpart of 66 HRC hardness. The composites were synthesized by capillary liquid copper infiltration into porous TiC-Gr preforms, obtaining materials with acceptable matrix-to-reinforcement bonding, homogeneous distribution of the reinforcing particles and absence of second phases. The tribological characterization indicated that the coefficient of friction decreases with the volumetric fraction of graphite in the composites as it enriches the wear surface. The pure copper matrix showed a wear rate up to four times that of the composites under maximum wear conditions. In all materials, the wear rate increased with applied load and sliding velocity. A higher graphite content led to a lower rate of wear so that the adhesion wear mechanism of pure copper changed to abrasion and delamination with tribochemical products on the surfaces of the Cu/TiC and Cu/TiC-Gr composites forming a mechanically mixed layer. The wear systems with graphite additions showed partial lubrication of the contact surfaces.
10.1016-j.wear.2021.204164	17	wear; composites; coating; friction; composite; coatings; surface; tribological; properties; wear resistance; resistance; powder; sliding; matrix; wear rate	Based on the concept of green design and development, FeS/Cu-Bi lead-free copper matrix composites were prepared by using FeS and Bi powder as lubricating phase to replace the lead in CuPb alloy. Surface modification of FeS powder by electroless plating and mechanical alloying of mixed powder by high-energy ball milling are effective strategies for preparing lead-free copper matrix composites. The effects of surface modification and mechanical alloying on the mechanical and tribological properties of the materials are studied. Results show that electroless nickel plating improves the mechanical locking and metallurgical bonding between mixed powder particles; enhances the interface bonding between FeS particles and copper matrix; and increases the hardness, impact toughness, and crushing strength by 29.7%, 19.4%, and 13%, respectively. The density and hardness of the composite prepared by electroless nickel plating combined with mechanical alloying increases by 11.4% and 40.6%, respectively, average friction coefficient decreases from 0.44 to 0.28, and wear rate decreases by 62%. Electroless plating and mechanical alloying reduce the microploughing and material transfer on the worn surface of the composites, and the abrasive wear and adhesive wear are remarkably improved.
10.1016-j.wear.2022.204275	17	wear; composites; coating; friction; composite; coatings; surface; tribological; properties; wear resistance; resistance; powder; sliding; matrix; wear rate	Cr, a promising abrasion component, has been introduced into Cu metal matrix composites (Cu-MMCs) to improve their high-energy braking performance. The Cu-Cr interfacial characteristics, worn surface/subsurface morphologies, and effect of Cr on the high energy braking behaviors of Cu-MMCs were measured in this study. The results indicate that an increase in Cr content prevented severe surface plastic deformation (0-5 vol. % Cr) and promoted the formation of mechanical mixed layer (MML) (15-20 vol % Cr), facilitated the improvement of wear resistance and the coefficient of friction, and reduced the thermal fade of composites. The main wear mechanism of the Cu-MMCs changed from adhesion (0-10 vol % Cr) or abrasion (10-20 vol % Cr) to delami-nation or mechanical mixing with an increase in braking energy density (BED). A series of corresponding friction, wear, and wear mechanism maps were established, which revealed the variation in the wear mechanism with the Cr content and BED.
10.1016-j.wear.2022.204517	-1		Heterogeneous gradient nanostructure has been evidenced to significantly reduce the coefficient of friction and wear loss. However, the tribological performance and underlying microscopic mechanisms of gradient nano -grained metals containing stable nanotwins with superior strength-ductility synergy are still unclear. In this work, an ultra-precision machining technique named single point diamond turning was developed to fabricate a stable gradient nanograined-nanotwinned layer on Cu-4.5%Al alloy (in which stacking fault energy was tailored through alloying of Al). The reciprocal dry-sliding tests under loads of 10 N and 35 N at room temperature were conducted on gradient nanograined-nanotwinned specimen and five Cu counterparts (uniformly refined grain sizes, nanotwins, and gradient nanograins). The gradient nanograined-nanotwinned specimen exhibits the un-precedented low steady-state coefficient of frictions (0.18-0.24), demonstrating further improvement in com-parison with the gradient nanograined Cu (0.31-0.35). Moreover, scanning electron microscope, white light interferometer, and high-resolution transmission electron microscope observations were mainly employed to evaluate the microstructural evolutions of worn surfaces and subsurface layers. It reveals that the worn sub-surface of stable gradient nanograined-nanotwinned specimen consists of grain refinement, slightly grain coarsening and dynamic recrystallization, and deformation layers along the depth direction, showing further effectively suppressed grain coarsening process relative to the gradient nanograined Cu. Accordingly, a twin boundary migration plus grain rotation-mediated grain coalescing process in the worn subsurface is elucidated to be responsible for such mechanical-structural stability of the gradient nanotwinned structure towards the su-perior tribological properties.
10.1016-j.wear.2022.204553	15	aging; strength; conductivity; electrical conductivity; electrical; mpa; treatment; strengthening; degrees; cu-; cold; precipitation; tensile strength; tensile; iacs	The microstructural evolution, electrical conductivity, and mechanical properties of a cast Cu-6Cr alloy were investigated after being homogenized at 900 degrees C for 4 h, hot-rolled by 80%, solid solution treated at 940 degrees C for 2 h, and subjected to two steps of cold rolling and aging treatment. After several thermomechanical processes (HR + SST + CR + AT + CR + AT), the microhardness (155.2 HV), yield strength (439.8 MPa), and ultimate tensile strength (473.7 MPa) are significantly improved, and maintained a good electrical conductivity of 87.0 %IACS. Furthermore, under a load of 50 N and speed of 200 r/min, the alloy demonstrates a good friction coefficient of 0.381 and a wear rate of 1.62 x 10-8 mm(3)/(N.m). The wear mechanisms of the experimental alloy were abrasive wear and oxidative wear under low loads and low speeds, and oxidative wear and adhesive wear under high loads and high speeds.
10.1016-j.wear.2022.204594	2	corrosion; surface; film; electrochemical; films; spectroscopy; layer; current; solution; potential; resistance; composition; x-ray; ions; showed	The tribocorrosion behavior of Cu-Ni-Zn alloy was investigated by using in-situ electrochemical controlled tri-bocorrosion technology in deep sea. The results showed that the tribocorrosion rate increased with hydrostatic pressure (i.e., seawater depth) at a rate of 1.05 x 10-5 mm3.N-1.m- 1.MPa- 1. Hydrostatic pressure had signif-icant influence on corrosion and tribocorrosion behaviors. At higher hydrostatic pressure, the cathodic reaction was accelerated and then the anodic dissolution process retarded. The passive film at higher hydrostatic pressure exhibited a larger amount of insoluble Cu(I) species (CuCl and Cu2O). On the other hand, with the increasing hydrostatic pressure, the adhesive wear decreased, while the abrasive and delamination wear aggravated. The increment in mechanical wear with hydrostatic pressure was determining factor for the tribocorrosion of Cu-Ni-Zn alloy in deep-sea.
10.1016-j.wear.2023.204726	-1		The yield strength of a metal may decrease if it is plastically deformed in an opposite direction prior to the test. This phenomenon is known as the Bauschinger effect, which affects wear of materials under different conditions. For instance, bi-directional sliding could lead to less wear than unidirectional sliding. However, it is unclear how the Bauschinger effect influences wear of strain-hardened metals with different crystal structures which influence the defect generation and annihilation. In this work, we investigated the Bauschinger effect on the wear resis-tance of cold-worked Cu (FCC) and Mg (HCP) combining experiments and molecular dynamics simulations. It was experimentally observed that strain-free Cu had a stronger Bauschinger effect than the cold-worked one, while the situation of undeformed and deformed Mg samples was opposite. The underlying mechanisms were studied via molecular dynamics simulations. It is found that the high-density dislocations in the cold-worked Cu weaken the Bauschinger effect, while the cold-worked Mg with fewer defects has more space for generation and cancellation of defects introduced by wear, leading to a stronger Bauschinger effect. Besides, the Bauschinger effect is also found at the oxide/metal interface, making the oxide scale on worn surfaces less easy to be scratched off during bi-directional sliding, which is beneficial to the wear resistance of metal since the tribo-oxide scale could help withstand the wearing force.
10.1016-j.wear.2023.204869	-1		Solid-solution hardening can increase the wear resistance of metals, involving two factors: the solute 1) pins dislocations, leading to increased hardness of the metals; 2) influences the atomic bond strength and thus Young's modulus, which also affects the resistance to dislocation generation and movement. Solute atoms generally increase hardness of the host metal but may increase or decrease its Young's modulus, which is related to the solute's electron work function (EWF). In this study, Cu (EWF = 4.65 eV) was hardened by solutes, Ni (EWF = 5.15 eV), and Mn (EWF = 4.1 eV), respectively. CuNi (10, 30, 60, 80 wt% Ni) and CuMn (2, 4, 6, 8 wt% Mn) alloys were prepared using an arc furnace. It is demonstrated that with Ni addition, both hardness and Young's modulus increased, while Mn addition led to a decrease in Young's modulus though the hardness was increased. As a result, the effect of Ni on the wear resistance of Cu is underestimated when predicted using the classic Archard equation, while that of Mn is overestimated. Such an issue of under-or over-estimation can be corrected using a wearing energy model, which takes into account the influence of Young's modulus on the wear resistance. The wearing energy model is a modified form of Archard equation, established by including wearing energy consumption via the relationships among atomic bond strength, Young's modulus, and EWF. Density functional theory (DFT) calculations on CuMn and CuNi alloys systems confirm a stronger metallic bond in CuNi with higher overall EWF, compared with that in CuMn showing a lower overall EWF.
10.1016-j.wear.2023.204890	16	wear; composite; composites; powders; milling; particles; powder; wt; sliding; friction; hardness; matrix; mechanical; surface; properties	In this research study, composites based on Copper-nickel (Cu-Ni) alloys, reinforced with particles of titanium carbide (TiC) and calcium fluoride (CaF2), were fabricated by powder metallurgy at 900 degrees C. Experimental studies were conducted to evaluate the tribological behaviour of TiC/CaF2 reinforced Cu-Ni matrix composites against counterpart 90-UTS rail steel. The worn surfaces were characterized by an Optical microscope (OM), 3D pro-filometer, field emission scanning electron microscope (FESEM), energy dispersive spectroscopy (EDS) and Raman spectroscopy. The lowest coefficient of friction (0.30) and lowest wear rate (5.36 x 10-5 mm3/N.m) were observed in the case of Cu-Ni/5 wt% TiC + 4 wt% CaF2 among all the composites. Cu2O, NiO, TiO2, Fe2O3 and Fe3O4 were formed, as a result of the tribo-oxidation on the wear tracks, which significantly affected the wear behaviour and wear mechanism. The main wear mechanism of the Cu-Ni matrix-based composites was a combination of adhesive wear, tribo-oxidation wear, delamination and minor abrasive wear.
10.1016-j.wear.2023.205013	17	wear; composites; coating; friction; composite; coatings; surface; tribological; properties; wear resistance; resistance; powder; sliding; matrix; wear rate	Copper matrix self-lubricating composites (CMSCs) are commonly used as sliding contacts in aerospace craft for their good electrical conductivity and wear resistance. In efforts to further improve performance and prolong the service life of CMSCs, the effect of WS2 nanosheet addition ranging from 10 to 25 wt% on the mechanical and tribological properties of Cu-WS2 self-lubricating composites was analyzed in this work. The dry sliding wear of composites against beryllium copper counter discs was measured at the load of 1 N. The increase in WS2 nanosheet leads to a decline in the strength of Cu-WS2 composite, whereas it improves the tribological properties presented as the reduction of friction coefficients and wear rates. Compared to Cu-WS2 with submicron WS2 sheet, Cu-WS2 with WS2 nanosheet shows both improved mechanical and tribological properties. The wear rate of Cu-WS2 composite with 25 wt% WS2 nanosheets is 61.2% lower than that with 25 wt% submicron WS2 sheets. The addition of WS2 nanosheet reduces the size of WS2 agglomerates and generates finely dispersed WS2 particles in Cu-WS2 composites. It not only promotes lubrication film continuous and smooth, but also inhibits the initiation and propagation of cracks at the worn subsurface by improving the strength of Cu-WS2 composite.
10.1016-j.wear.2024.205428	-1		This study focuses on the fabrication of Cu-based self-lubricating composites with desirable mechanical and friction properties using electroless plating and hot-pressing sintering and the analyses of the mechanical properties, friction properties and microstructures. High-strength Cu-15Ni-8Sn alloy and Cu-coated MoS2 prepared via electroless plating were selected to be the matrix and self-lubrication particles, respectively. A composite containing 20 vol% Cu-coated MoS2 (C20) is developed, which has not only a desirable friction property but also a high mechanical property, e.g., transverse-rupture-strength of 433 MPa. The average friction coefficient and wear rate of C20 are 0.065 and 1.65 x 10- 7 mm3/N & sdot;m, respectively, which are 13.3 % and 23.6 % lower than the composite containing 20 vol% unmodified MoS2 (M20). The desirable mechanical property of C20 is attributed to the high-performance matrix, the good combination between the matrix and MoS2 particles and the uniform distribution of MoS2 particles in C20, and its good friction property owes to the formation of the solid lubricating film with a high adhesive strength during the wear process.
10.1016-j.wear.2024.205591	14	strength; properties; conductivity; electrical; mechanical; cu-; grain; mpa; electrical conductivity; aging; precipitation; phase; mechanical properties; tensile; phases	Cu-based immiscible alloys have significant potential application value in the field of electrical contacts. This study investigated the tribological behavior of Cu-Fe-P immiscible alloys produced via laser powder bed fusion (LPBF) under current-carrying conditions. The alloys consist of softer epsilon-Cu phase and harder Fe-rich phases. The Fe-rich phase acts as a protective reinforcement during current-carrying friction and wear tests, improving the wear resistance of the alloy. With the increasing current, the coefficient of friction initially rose and then decreased, whereas the wear rate showed a gradual increase. At low currents (0, 2, 3 and 5 A), mechanical wear predominantly governs the wear mechanism. As the current increases, the mechanical wear gradually transitions from adhesive wear to abrasive wear, accompanied by weak oxidative wear. At higher currents (7 A and 10 A), the wear mechanism is dominated by arc erosion wear and oxidative wear. Notably, when the current exceeded 2 A, an oxide film consisting of CuO, Fe2O3, and Fe3O4 formed, enhancing the frictional properties of the alloy. Once the current surpassed 5 A, the arc discharge occurred at high currents, forming molten phases and arc erosion pits on the worn surface of the Cu-Fe-P immiscible alloy.
10.1016-j.wear.2024.205715	-1		Current-carrying friction and wear issues have a significant impact on the performance and service life of electrical systems. This paper investigated lubricating behavior of gallium-based liquid metal (GLM) for the Cu/ Al current-carrying tribo-pair. The results showed that when there is GLM lubrication, the coefficient of friction is in the range of 0.19-0.27, and the wear rate of Cu alloy is in the range of 0.87 x 10-5 mm3/Nm to 1.83 x 10-5 mm3/Nm. Compared without GLM lubricant, the coefficient of friction is decreased by approximately 1.3-2.5 times, and the wear rate is decreased by around 3.1 to 8.3 times. Its main lubrication mechanism is to generate a uniform and stable Ga-Al metal film at the friction interface, thereby effectively preventing the direct contact between the tribo-pairs and the occurrence of arc ablation.
10.1016-j.wear.2025.206100	-1		This study examines the effect of deformation-induced grain refinement on the tribological behavior of CuNi2SiCr alloys under electrical current-carrying contact conditions of 0A, 5A, 15A, and 25A. The results demonstrate that the formation of an ultrafine-grained (UFG) structure in the matrix enhanced the wear resistance of the alloy in all test conditions. The improvement in wear resistance is more pronounced under electrical contact sliding conditions. With the formation of the UFG structure, the wear volume loss decreased by 18 % compared to the coarse-grained (CG) sample under currentless conditions. The decrease seen in volumetric loss is achieved as 27 %, 42 %, and 67 % for conditions of 5A, 15A, and 25A, respectively. Additionally, as the intensity of electric current increases, the average friction coefficient value of the samples rises, exhibiting significant fluctuations during the steady-state period of rubbing with increasing electric current intensity. Furthermore, the dominant wear mechanism depends on the level of electrical current intensity. While adhesive, abrasive, and oxidative wear mechanisms are operative for coarse (CG) and UFGed CuNi2SiCr samples at low-intensity electrical current conditions, arc-induced erosion, oxidative, and severe abrasive-based wear are more active at higher current intensities for both samples.
10.1016-j.wear.2025.206276	-1		Wear is an inevitable issue for mechanical equipment, leading to increased failure rates and reduced service life. Copper (Cu) and its alloys exhibit high electrical and thermal conductivities; however, the insufficient hardness and poor wear resistance limit their application in electronic and electrical engineering. To address the incompatibility between electrical conductivity and tribological properties in Cu materials, dual-scale TiB2 ceramic particles were used to reinforce Cu matrix composites, which were fabricated via spark plasma sintering. The effect of TiB2 content on the microstructure, hardness, electrical conductivity, and wear resistance of the TiB2/Cu composites was investigated. The results indicated that the TiB2 ceramic particles were well dispersed within the Cu matrix. The hardness of the composites was significantly improved without a substantial reduction in electrical conductivity. Additionally, the compressive strength and wear resistance of the Cu-based composites were enhanced by the addition of dual-scale TiB2 ceramics. The wear resistance of the composite with 15 wt% TiB2 was 3.06 times higher than that of the composite with 5 wt% TiB2 under an applied load of 20 N. The dominant wear mechanisms of the composites were adhesive wear, oxidation wear, and abrasive wear.
10.1016-j.wear.2025.206373	14	strength; properties; conductivity; electrical; mechanical; cu-; grain; mpa; electrical conductivity; aging; precipitation; phase; mechanical properties; tensile; phases	In this study, Cu-based contact materials reinforced with 20 wt% high-entropy alloy particles of CuCrNiCoFe were successfully prepared by combining ball milling and spark plasma sintering (SPS) technology. The microstructure and fundamental physical properties of the novel Cu-20HEAs samples were investigated, and their arc erosion behavior was systematically evaluated. The results demonstrate that after low-speed ball milling for 3 h, the high entropy alloys (HEAs) particles achieved uniform distribution within the Cu matrix. Following SPS, the material exhibited excellent overall performance, with an electrical conductivity of 25.5 %IACS, a Vickers hardness of 90.1 HV, and a density of 8.77 g/cm3. The Cu-20HEAs samples displayed favorable resistance to arc erosion during vacuum arc breakdown testing. During arcing, a larger arc diffusion area facilitated rapid dispersion of arc energy, effectively suppressing splashing of the Cu matrix and minimizing mass loss. In 50 arc erosion tests, the dielectric strength of the sample exhibited minimal fluctuation, demonstrating excellent operational stability and a prolonged service life.
10.1016-S0010-938X(01)00041-5	2	corrosion; surface; film; electrochemical; films; spectroscopy; layer; current; solution; potential; resistance; composition; x-ray; ions; showed	The corrosion product films of 70Cu-30Ni alloy, composed of recrystallized grains or deformed and recrystallized grains, were investigated in 3.5% NaCl and natural seawater by electrochemical techniques, SEM, EDX and AES. The recrystallized alloy displayed a steady increase in the polarization resistance while the alloy of incomplete recrystallization kept its polarization resistance at a low level as increasing the immersion time in 3.5% NaCl. The films formed on the recrystallized alloy in seawater were thin, uniform and rich in nickel. After longterm immersion, the films, still thin and protective, consisted of convex lines and smooth zones between the lines. The convex lines were richer in nickel and contained more seawater species than the zones, so this led the lines to preferentially dissolve and new lines to appear where the film grew slower. Immersed in seawater, the alloy of incomplete recrystallization showed thick, loose and porous films, of which the inner layer was denickelified and the outer layer contained a great amount of seawater species, and of which the underlying substrate was found with severe intergranular corrosion, The tube specimens of incomplete recrystallization for four-year immersion were perforated by intergranular corrosion.
10.1016-S0010-938X(02)00257-3	2	corrosion; surface; film; electrochemical; films; spectroscopy; layer; current; solution; potential; resistance; composition; x-ray; ions; showed	The literature dealing with the electrochemical corrosion characteristics of unalloyed copper in aqueous chloride media is examined. The enormous quantity of polarisation and mixed/corrosion potential data that has been made available in the literature over the last 50 years has been compiled and discussed in a comprehensive review. For a wide range of electrode geometries, the importance of the chloride ion and the mass transport of anodic corrosion products on the corrosion behaviour of copper are made clear for both freshly polished and 'filmed' surfaces.
10.1016-S0011-9164(99)00165-4	2	corrosion; surface; film; electrochemical; films; spectroscopy; layer; current; solution; potential; resistance; composition; x-ray; ions; showed	The paper describes a fundamental investigation of the corrosion behaviour of Cu-Ni-Fe-Mn alloys, containing nominally 10% Ni and 30% Ni, in distilled water. The study involved exposure of specimens to distilled water (1.5-7 mu S/cm) at 20-80 degrees C with and without injected carbon dioxide. At 20 degrees C upon initial exposure to distilled water, the 10% Ni alloy exhibited somewhat active corrosion behaviour during anodic polarisation potentiodynamic scans but, after a few days' exposure, more-passive behaviour of both alloys was indicated with the 30% Ni material demonstrating better corrosion resistance than the lower-Ni alloy. However, at higher temperatures, the superiority of the 30% Ni alloy was less evident especially in the presence of dissolved carbon dioxide. Indeed, even a relatively short period of bubbling pure CO2 following a long period in distilled water, reduced the corrosion resistance of both alloys. Microscopic examination of specimens revealed susceptibility to pitting attack and, to a lesser extent, crevice corrosion after extended exposures at 20-80 degrees C.
10.1016-S0020-7403(02)00011-5	4	transformation; martensite; martensitic; phase; shape; beta; memory; shape memory; temperature; temperatures; martensitic transformation; gamma; transformation temperatures; effect; thermal	The moment-curvature hysteresis loops (for single cycle) under pure bending were experimentally determined for Cu-Al-Be single crystal, Ni-Ti and Cu-Zn-Al polycrystal samples using specially designed device. The comparison with the theoretical loops is presented for linear strain-hardening and ideal pseudoelasticity models discussed in (Int. J. Mech . Sci. 2001;43:1339). All theoretical constants were determined using simple-tension data and thermo dynamical identities. The tensile-compression dissymmetry effect is accounted for and non-linear differential equation describing the motion of neutral plane is derived for beams with arbitrary symmetric cross-section. The evidence of dissymmetry effect in Cu-Al-Zn is provided by application of metallographical and mechanical techniques. But the experiments and modelling have shown that the tension/compression asymmetry has in fact little influence on the moment-curvature responses on SMA beams.
10.1016-S0020-7403(97)00046-5	4	transformation; martensite; martensitic; phase; shape; beta; memory; shape memory; temperature; temperatures; martensitic transformation; gamma; transformation temperatures; effect; thermal	Microstructure-based micromechanics models have to be developed in order to successively predict complex thermomechanical behaviors of shape-memory alloys (SMA). However, a proper implementation of the deformation mechanism-motion of internal interfaces in solid state-into the micromechanics models of SMA polycrystals is very important. In this work, experimental characteristics of the deformation mechanism surveyed from literature data obtained from uniaxial loadings of SMA single crystals are summarized. Original results of thermomechanical tension/compression loading experiments on CuAlNi and CuAlZnMn single crystals and CuAlZnMn polycrystals are also reported. Oriented single crystals may transform into different martensitic phases under various orientations of the uniaxial loading axes and sense of the applied stress. This phenomenon is called martensite formation anisotropy and possible consequences for thermomechanical behaviors of CuAlZnMn polycrystals are suggested. (C) 1997 Published by Elsevier Science Ltd.
10.1016-S0022-0248(00)00563-7	-1		The Bridgman technique was used to produce Cu-1.8 wt% Be single crystals. The growth methodology is presented and optimal growth conditions for the production of CuBe single crystals utilizing the Bridgman technique were determined. The influence of material purity, the temperature profile, and the translation rate on the crystal growth process are discussed. The as-grown single-crystal material produced was investigated with optical microscopy, scanning electron microscopy, X-ray diffraction, and spectrometry techniques. Segregation of impurities and alloying elements occurred as a consequence of recrystallization and resulted in a variation of composition over the length of the single crystals grown. The compositional variation was characterized for crystals that underwent single and double solidification passes. Structures occurring at multiple length scales were documented throughout the single crystal material. Precipitate structures consisting of beta- and gamma-phases in a Cu-rich cc-matrix were identified. Structures aligned with the {100} planes of the parent phase were also observed.
10.1016-S0022-0248(00)01008-3	0	solidification; phase; magnetic; magnetic field; undercooling; field; liquid; separation; peritectic; immiscible; cu-; dendrite; phase separation; microstructure; primary	The influence of growth direction on the monotectic structure of the Cu-Pb alloy is studied. In order to examine the influence under a ly environment, both the upward (opposite to the direction of gravity) and downward (the direction of gravity) unidirectional solidifications (UDS) are carried out. In the case of the upward UDS, a banded structure, which consists of Pb-rich and Cu-rich layers, is observed. The L-2 droplets pile up in front of the solid/liquid interface. On the other hand, in the downward UDS, the irregularly shaped L-2 phase uniformly disperses in the specimen and no banded structure is found. The gravity macrosegregation of the L-2 liquid is observed at the bottom of the molten alloy in the downward solidified specimen. This is caused by the difference in the density between the L-1 and L-2 phases. Furthermore, a mechanism for the formation of a banded structure is suggested. This mechanism suggests that the coalesced L-2 phase covers the solid/liquid interface by producing a Pb-rich layer that permits an increase in the undercooling of the L-1/L-2 interface compared to the monotectic temperature. As nucleation of the CL-Cu phase occurs on the Pb-rich layer, the coexisting three phases are then restored. The temperature at the growth front is also returned to the monotectic temperature. The repetition mentioned above will result in the banded structure found in the upward UDS. :
10.1016-S0022-3093(01)00535-X	2	corrosion; surface; film; electrochemical; films; spectroscopy; layer; current; solution; potential; resistance; composition; x-ray; ions; showed	Cu88Co12 samples have been obtained by electrodeposition and laser ablation and have been annealed at increasing temperatures (450 degreesC, 500 degreesC and 550 degreesC) to compare the influence of the fabrication method on the magnetotransport properties of the samples. Magnetoresistance (MR) and X-ray diffraction (XRD) measurements show different properties between the samples prepared by the two techniques. It was found that the electrodeposited (ED) samples had a larger MR. The properties of the laser-ablated samples depend on the deposition process, showing an anisotropy when prepared with a smaller target rotation speed.
10.1016-S0022-3093(01)01047-X	11	glass; bulk; metallic; bulk metallic; gfa; bmg; glassy; metallic glass; ability; bulk metallic glass; amorphous; addition; crystallization; mm; glass-forming	he effect of Sn substitution for Ni on the glass-forming ability was studied in CU47Ti33Zr11Ni8-xSnxSi1 (x = 0, 2,4, 6, 8) alloys by using thermal analysis and X-ray diffractometry. With increasing x from 0 to 8, the glass transition temperature. T-g of melt-spun CU47Ti33Zr11Ni8-x SnxSi1 alloys increased gradually from 720 to 737 K. On the other hand, the crystallization temperature, T_ increased from 757 K at x = 0 to 765 K at x = 2, being nearly same with further increase of x. Partial substitution of Ni by Sn in CU47Ti33Zr11Ni8Si1 promotes the glass formation. Both amorphous Cu47Ti31Zr11Ni8-xSnxSi1 alloys prepared by melt spinning and injection casting showed similar crystallization process during continuous heating in DSC. Temperature range of undercooled liquid region exhibits good correlation with the critical diameter for the formation of an amorphous phase in injection casting.
10.1016-S0022-3093(03)00338-7	-1		Cu57.5Zr30Ti10Ni2.5 and Cu55Zr30Ti10Ni5 bulk glassy alloys exhibit high compressive fracture strength of 2200 and 2100 MPa, respectively, and a large supercooled liquid region. Addition of Ni significantly influences devitrification of Cu-Zr-Ti glassy alloy. Cu57.5Zr30Ti10Ni2.5 glassy alloy primarily forms an intermediate intermetallic compound on heating prior to equilibrium by the diffusion-controlled growth with low energy barrier for nucleation whereas Cu55Zr30Ti10Ni5 and Cu52.5Zr30Ti10Ni7.5 glassy alloys devitrify forming equilibrium Aba2 (Cu,Ni)(10)(Zr,Ti)(7) phase with slightly reduced lattice parameters compared to Cu10Zr7 and a small fraction of an unidentified phase. However, preexisting nanoscale phase of less than 10 nm in size is located in the spaces between the (Cu,Ni),()(Zr,Ti)7 dendritic phase in the spaces between nanoparticles.
10.1016-S0022-3093(96)00451-6	-1		Heat capacity measurements on liquid stable and undercooled pure Au samples and Cu-Ni alloys were performed. Applying the melt fluxing technique, undercooling levels of 202 K and 272 K, respectively, could be reached. The specific heat of the liquid, C-p(1) could be measured directly by calorimetric diagnostics while undercooling the melt with a cooling rate of 10 K/min. Both metals show a rather weak dependence of C-p(1) on temperature. The differences of the thermodynamic functions between undercooled liquid and solid state were derived from the measured data of C-p and Delta H-f- the enthalpy of fusion, In particular the difference in the Gibbs free energy Delta G is compared to well known semiquantitative approximations. It is found that even the simple linear approximation can fit adequately the Delta G-data of the systems under study.
10.1016-S0022-3093(98)00531-6	13	clusters; atomic; glass; atoms; composition; dynamics; metallic; icosahedral; glasses; simulations; molecular; cu-zr; molecular dynamics; metallic glasses; structural	A neutron inelastic scattering study is presented of Cu64Zr36 metallic glass, with isotope substitution for Cu, and the results are compared to earlier data for Ni64Zr36 (Ni isotopic substitution). The availability of two samples for each system, with different isotope content, has enabled partial vibrational densities of states to be obtained for both materials. The ratios of the average force constants, B-Cu/B-Zr and B-Ni/B-Zr, are estimated to be 0.68 +/- 0.1 and 0.73 +/- 0.1, respectively. The interatomic interaction of the Cu and Ni atoms with respect to all neighbors is weaker than that of the Zr atoms.
10.1016-S0022-3093(98)00550-X	-1		The development of a methodological approach and experimental protocols have permitted the accurate evaluation of some of the key parameters of a ball milling process, such as the impact energy and the number of impacts. Thus, a detailed description of the milling regime in terms of energy transfer to the powders has been possible. On this basis, the crystal to amorphous state reaction of Cu-Ti mixture has been studied for widely differing milling conditions. The analysis of X-ray diffraction data has shown correlations between the parameters of the milling treatment which relate to energy and the structural evolution of the amorphous phase. An attempt has been made to relate the observed kinetic features to a rate law involving microscopic pulse energy and structural factors.
10.1016-S0022-3115(00)00205-1	-1		High-energy neutron irradiation on copper alloys will cause atomic displacements and nuclear transmutation, which will lead to degradation of thermal conductivity and mechanical properties. To study the synergistic effects, we have utilized Cu-Ni-Zn alloys to simulate the effect of transmutation. Thermal conductivity of these alloys has been derived from electrical resistivity measurements between 298 and 770 K. These alloys were also irradiated with 2.4 MeV copper self ions at room temperature and the mechanical properties were evaluated from micro-hardness measurements. The resistivity of the copper alloys depends linearly on nickel concentration. However, the effect of zinc is complex and may be less prominent than the nickel effect. It is suspected that dezincification has taken place. The change in microhardness shows saturation at a displacement dose of around 0.5 dpa. There is a slight influence of alloying elements, particularly zinc, on the fluence dependence of hardness change.
10.1016-S0022-3115(00)00359-7	7	irradiation; shear; grain; ta; deformation; size; radiation; voids; nanocrystalline; simulations; similar; void; temperature; irradiated; boundaries	Transmission electron microscope (TEM) disks of pure copper and copper containing 0.17-10% Ni were neutron irradiated at 210 degreesC and 420 degreesC in Hf-shielded capsules in the High Flux Isotopes Reactor to doses of 13.5 and 14.9 displacements per atom (dpa), respectively. Void swelling was not observed in any of the specimens irradiated at 210 degreesC. Instead, a high density of stacking fault tetrahedra (SFTs) and a moderate density of dislocation loops were observed. There was no evidence for defect cluster patterning (wall formation) in any of the specimens irradiated at 210 degreesC. The SFT density was independent of Ni content, whereas the loop density was highest in the alloy containing similar to2% Ni. Pronounced void swelling was observed in all of the specimens irradiated at 420 degreesC. A void denuded zone of similar to2 mum width was observed adjacent to grain boundaries. The void swelling in copper containing, similar to2% Ni showed a pronounced maximum in a 10-mum wide band adjacent to the grain boundary denuded zones. Matrix voids aligned along [1 1 0] directions were observed in Cu-10%Ni irradiated at 420 degreesC. The occurrence of the peak swelling zone and the partial ordering of voids are both consistent with the predictions of the recent production bias model which includes 1-D diffusional transport of clusters of self-interstitial atoms.
10.1016-S0022-3115(02)01252-7	7	irradiation; shear; grain; ta; deformation; size; radiation; voids; nanocrystalline; simulations; similar; void; temperature; irradiated; boundaries	Oxide dispersion strengthened copper (ODS-Cu) alloys GlidCop CuAl15 and CuAl25 were irradiated with Cu2+ ions at 573-773 K up to doses of 30 dpa. Void swelling was observed in all specimens irradiated at temperatures ranging from 573 to 673 K. In CuAl15 brazed with graphite at 1083 K, mean grain size was about 800 nm. Voids were observed in grains larger than 1 mum but not in smaller than 500 nm in diameter. The CuAl25 joined with SUS316 by hot isostatic pressing (HIP) at 1323 K had a mean grain size of 60 mum because of a large grain growth during the HIP process and showed large void swelling. Small grain size is effective in suppressing void swelling due to strong sink effects of grain boundaries for the point defects. The present results indicate that joining at high temperatures may reduce the void swelling resistance of GlidCop copper alloys.
10.1016-S0022-3115(96)00320-0	-1		GlidCop(R) AL-25 LOX-80 grade plates manufactured by processes relevant to ITER first wall copper alloy requirements were tested in the temperature range of 20-350 degrees C. Plate manufacturing methods included hot isostatic pressing (HIP), extrusion (EXT), and extrusion followed by cross-rolling (EXT + XROLL). Tests that were performed included tensile, fracture toughness, impact toughness, and creep. The EXT + XROLL plate was found to have higher total elongation, reduction of area, and fracture toughness values than the EXT and HIP plates. All three processes had similar ultimate tensile and 0.2% yield strengths. The HIP material exhibited a lower creep rate than EXT + XROLL. The EXT and the EXT + XROLL plates had similar impact toughness values, which were higher than the HIP plate. Overall, the EXT + XROLL plate had the best combination of properties of the three processes examined.
10.1016-S0022-3115(98)00276-1	-1		A time dependent permeation method has been used to measure the transport and inventory parameters of hydrogen and deuterium in the precipitation hardened (PH) Cu-0.65 wt% Cr-0.08 wt% Zr alloy (ELBRODUR HF). The measurements cover the temperature range from 553 to 773 K using a hydrogen or deuterium pressure in the range 1-100 kPa. The permeabilities, diffusivities and Sieverts' constant values for ELBRODUR obtained in this work were about 2 time higher, 2 times lower and between 3 and 10 time higher respectively to that of Cu (F. Reiter et al, A compilation of Tritium Material Interaction Parameters in Fusion Reactor Materials, EUR 15217 EN (1993)) in the temperature range studied. Using the measured diffusivities smd Sieverts' constant values for H-2 and D-2 and a quantum-mechanical model, an extrapolation for tritium is also presented.
10.1016-S0022-3115(98)00277-3	-1		Fracture resistance of the current ITER first wall configuration, a copper alloy-stainless steel layered structure, is a major design issue. The question of dynamic crack propagation into and through the first wall structure is examined using dynamic finite element modeling (FEM). Several layered configurations that incorporate both strain and frictional energy dissipation during the fracture process are considered. With fixed overall specimen geometry, the energy required to extend a precrack is examined as a function of material properties, and the layer structure. It is found that the crack extension energies vary dramatically with the fracture strain of materials, and to a much lesser extent with the number of layers. In addition, it is found that crack propagation through the lower ductility copper alloy layer may be deflected at the stainless steel-copper interface and not result in total fracture of the structure. Although the total energy required is affected only to a small degree by the interface properties, the time to extend the precrack is strongly affected. By making proper selections of the interface and the layered material, crack propagation rates and the possibility of full fracture can be substantially reduced.
10.1016-S0022-3115(98)00333-X	5	materials; thermal; heat; properties; material; welding; sintering; fusion; strength; laser; heat sink; thermal conductivity; mechanical; sink; manufacturing	An austenitic stainless steel (316LN), an oxide-dispersion-strengthened copper alloy (GlidCop A125), and a precipitation-hardened copper alloy (Cu-Cr-Zr) are the primary structural materials for the ITER first wall/blanket and divertor systems. While there is a long experience of operating 316LN stainless steel in nuclear environments, there is no prior experience with the copper alloys in neutron environments. The ITER first wall (FW) consists of a stainless steel shield with a copper alloy heat sink bonded by hot isostatic pressing (HIP). The introduction of bi-layer structural material represents a new materials engineering challenge; the behavior of the bi-layer is determined by the properties of the individual components and by the nature of the bond interface. The development of the radiation damage microstructure in both classes of materials is summarized and the effects of radiation on deformation and fracture behavior are considered. The initial data on the mechanical testing of bi-layers indicate that the effectiveness of GlidCop A125 as a FW heat sink material is compromised by its strongly anisotropic fracture toughness and poor resistance to crack growth in a direction parallel to the bi-layer interface.
10.1016-S0022-3115(98)00387-0	7	irradiation; shear; grain; ta; deformation; size; radiation; voids; nanocrystalline; simulations; similar; void; temperature; irradiated; boundaries	Dispersion strengthened (DS) Cu-Al25 alloy containing small Al2O3 particles (similar to 4 nm in diameter) was irradiated by 300 keV Cu+ ion to doses of 10 dpa and 30 dpa with a displacement rate of 3.7 x 10(-2) dpa/s at room temperature, which simulates the effects of high energy primary knock-on atoms (PKA) produced by 14 MeV neutrons. Microstructural evolution was investigated by transmission electron microscopy (TEM). Selected area diffraction (SAD) was used to study the phase stability of alumina under irradiation. The defect cluster structure formed by irradiation was investigated by dynamic two-beam techniques. Small particles of Al2O3 were dissolved under ion irradiation with increasing fluences. A large number of small Frank vacancy and interstitial dislocation loops (similar to 5 nm in diameter) with different Burgers vectors of a/3[1 1 1] are produced by ion irradiation. At the region adjacent to the irradiation surface the number of vacancy loops was greater than that of interstitial ones. This result is in good agreement with the computer simulation results.
10.1016-S0022-3115(98)00708-9	7	irradiation; shear; grain; ta; deformation; size; radiation; voids; nanocrystalline; simulations; similar; void; temperature; irradiated; boundaries	The effect of concentrated Ni and Cu solute atoms in the Cu-Ni system on the formation of voids has been examined using Cu, Cu-8 at% Ni, Ni-8 at% Cu and Ni irradiated with fast-neutrons in the FFTF-MOTA. Both solute atoms introduced smaller voids in the grains of the concentrated alloys than voids in the normal grains of pure-Cu and pure-Ni. Slight increase of irradiation temperature and the higher dose of fast-neutrons induced coalescence of voids in the grains of Ni-8 at% Cu, but it resulted in the abrupt decrease of the concentration of small voids in the grains and the formation of heterogeneously distributed larger voids near grain boundaries in Cu-8 at% Ni. Heterogeneous distribution of larger voids was also observed in other materials. Annealing at higher temperatures induced segregation of impurity atoms at a void surface in Ni-8 at% Cu.
10.1016-S0022-3115(98)00746-6	7	irradiation; shear; grain; ta; deformation; size; radiation; voids; nanocrystalline; simulations; similar; void; temperature; irradiated; boundaries	Effects of He implantation on radiation induced segregation (R1S) in Cu-Au and Ni-Si alloys were investigated using in situ Rutherford backscattering spectrometry during simultaneous irradiation with 1.5-MeV He and low-energy (100 or 400-keV) He ions at elevated temperatures. RIS during single He ion irradiation, and the effects of pre-implantation with low-energy He ions, were also studied. RIS near the specimen surface, which was pronounced during 1.5-MeV He single-ion irradiation, was strongly reduced under low-energy He single-ion irradiation, and during simultaneous irradiation with 1.5-MeV He and low-energy He ions. A similar RIS reduction was also observed in the specimens pre-implanted with low-energy He ions. The experimental results indicate that the accumulated He atoms cause the formation of small bubbles, which provide additional recombination sites for freely migrating defects.
10.1016-S0022-3115(98)00799-5	-1		Cyclic ball indentation tests for Fe-Mn-Cu-C alloys with and without annealing treatments were simulated by finite element method (FEM) calculation using a 2D-axisymmetric model with a ri,rigid surface indenter. When the friction between the indenter and the specimen was taken into account (friction coefficient is 0.3), the calculation gave a good simulation of the plastic deformation and true stress-plastic strain curve obtained from the actual indentation tests except for the stress decrease in a higher strain region. The stress decrease was not observed in the stress-strain curve from the simulation of the indentation test. The decrease in the experimental curves was explained well by the existence of the higher tensile region that was found in the stress distribution map from the FEM calculation.
10.1016-S0022-3697(03)00125-2	-1		Cu-chalcopyrite (Ch) Cu(Al,Ga,In)(S,Se)(2) Compounds and alloys were grown epitaxialy on various substrates by low-pressure metalorganic vapor phase epitaxy. They grew in such a manner that the lattice mismatch between the epilayer and the substrate became minimum. Growth of anion and cation alloys revealed that the vapor pressure of Al-S reactants is much higher than that of Ga-S or Al-Se ones. Most of residual strain in the epilayer was assigned as being due to the pseudomorphic stress for those having small lattice mismatch (<1%) against the substrate and to the thermal stress for large lattice mismatch (>1%) ones, and the strain problem was solved by the use of Ch structure substrate. All single-domain compound epilayers, namely CuAlS2, CuAlSe2, CuGaS2, CuGaSe2, CuInSe2, and their alloys exhibited predominant excitonic photoluminescence peaks. A noticeable excitonic feature was found in the PL spectra of CuAlS2, CuGaS2 and CuGaSe2 even at 300 K. Band diagram of Cu(AI,Ga)(S,Se)(2) system was discussed, and they are considered to offer the TYPE-I heterostructures between the corresponding narrow bandgap materials and wide bandgap ones.
10.1016-S0022-5096(02)00007-8	4	transformation; martensite; martensitic; phase; shape; beta; memory; shape memory; temperature; temperatures; martensitic transformation; gamma; transformation temperatures; effect; thermal	Biaxial proportional loading such as tension (compression)-internal pressure and bicompression tests are performed on a Cu-Zn-Al and Cu-Al-Be shape memory polycrystals. These tests lead to the experimental determination of the initial surface of phase transformation (austenite --> martensite) in the principal stress space (sigma(1), sigma(2)). A first micro-macro modeling is performed as follows. Lattice measurements of the cubic austenite and the monoclinic martensite cells are used to determine the nature of the phase transformation, i.e. an exact interface between the parent phase and an untwinned martensite variant. The yield surface is obtained by a simple (Sachs constant stress) averaging procedure assuming random texture. A second modeling, performed in the context of the thermodynamics of irreversible processes, consists of a phenomenological approach at the scale of the polycrystal. These two models fit the experimental phase transformation surface well.
10.1016-S0022-5096(02)00014-5	-1		The formation of martensite at a notch tip in a CuAlNi shape memory alloy loaded in tension is studied. The geometry of the initial martensite plate to form at the notch is predicted theoretically, using the stress field at a crack tip in an anisotropic linearly elastic body together with a listing of all possible austenite-martensite interfaces from the Crystallographic Theory of Martensite (CTM). The stress field and CTM analyses are combined through a selection criterion based on computing the work available from the stress field to transform to each austenite-martensite interface. The resulting predictions are compared to experimentally observed microstructures in notched specimens of single crystal CuAlNi loaded in tension for eight notch orientations. Results show that the available work criterion accurately predicts the orientation, number and order of the austenite-martensite interfaces that initially form near a crack.
10.1016-S0022-5096(02)00029-7	4	transformation; martensite; martensitic; phase; shape; beta; memory; shape memory; temperature; temperatures; martensitic transformation; gamma; transformation temperatures; effect; thermal	This paper is concerned with micromechanical modelling of stress-induced martensitic transformations in crystalline solids, with the focus on distinct elastic anisotropy of the phases and the associated redistribution of internal stresses. Micro-macro transition in stresses and strains is analysed for a laminated microstructure of austenite and martensite phases. Propagation of a phase transformation front is governed by a time-independent thermodynamic criterion. Plasticity-like macroscopic constitutive rate equations are derived in which the transformed volume fraction is incrementally related to the overall strain or stress. As an application, numerical simulations are performed for cubic beta(1) (austenite) to orthorhombic gamma(1)' (martensite) phase transformation in a single crystal of Cu-Al-Ni shape memory alloy. The pseudoelasticity effect in tension and compression is investigated along with the corresponding evolution of internal stresses and microstructure.
10.1016-S0029-5493(00)00420-9	-1		The material investigations presented confirm the results of earlier MPa investigations that the service-induced hardening and decrease in toughness in WE 36 materials are caused by the precipitation of copper. In the initial state of the material, generally only a part of the alloyed copper is precipitated. The other part is still in solution and can be precipitated during long-term operation at temperatures above 320-350 degreesC. The copper precipitation leads to a distortion of the crystal lattice surrounding the copper precipitates and yields internal micro-stresses. If the number and size of the copper precipitates change during operation of a component, a change of the residual-stress level occurs. Formation and growth of copper precipitates was simulated using atomistic calculations. In addition, it was possible to mathematically follow the movement of dislocations and their attachment to precipitates. In this way the nano-simulation was established as a scientific method for the numerically based understanding of precipitation hardening. The results obtained from load stress-related Barkhausen noise measurements demonstrated that these micro-magnetic procedures are generally suitable for the verification of copper precipitation. The goal of current research is to establish these findings statistically through further experimental measurements. In addition, the influence of different deformation states, macro residual stress, and thermal-induced residual stress have to be researched. This is important for future developments of tron-destructive inspection techniques applied to inservice components.
10.1016-S0039-6028(01)01243-2	-1		The growth of Cu on Si(1 1 1) surface with and without hydrogen termination was studied with low energy electron microscopy. On the clean surface the two-dimensional 5 x 5 incommensurate layer is first formed followed by the formation of three-dimensional (3D) islands. On the hydrogen-terminated surface the formation of the 5 x 5 structure is suppressed and nano-scale 3D islands decorate the steps and domain boundaries of the delta7 x 7 structure. Many LEED spots from the nano-islands move with electron energy, which indicates that the islands are faceted. From the analysis of the LEED pattern it is suggested that the nano-islands are the (1 1 1)-oriented beta -phase Cu-Si alloy and are terminated by (1 1 1), {5 5 4} and {15 16 13} faces.
10.1016-S0039-6028(02)01816-2	-1		The geometric structure and compositional profile of aCu{100}-c(2 x 2)-Pt surface alloy formed by thermal activation of a monolayer Pt film has been determined by tensor low energy electron diffraction (LEED). A wide range of models have been tested. The favoured model consists of an ordered c(2 x 2) CuPt underlayer below a Cu terminated surface. Models involving a mixed ordered CuPt layer outermost may be definitively ruled out. The average T-matrix approximation (ATA) has been applied allowing variable Pt concentrations to be introduced into both the outermost layer and deeper into the selvedge (layers 3 and 4) in the form of a random substitutionally disordered CuxPt1-x alloy. The favoured concentration profile corresponds to an almost pure outermost Cu monolayer (Theta(pt) = 10 +/- 10 at%) with Pt concentrations of 20 20 and 30 30 at% in layers 3 and 4 respectively. Introduction of Pt into the surface layers induces a significant expansion of the selvedge yielding modification of the outermost three interlayer spacings to 1.84 +/- 0.02 Angstrom (Deltadz(12) = +1.9 +/- 1.1%), 1.91 +/- 0.03 Angstrom (Deltadz(23) = +5.8 +/- 1.7%) and 1.89 +/- 0.03 Angstrom (Deltadz(34) = + 4.7 +/- 1.7%). The rippling in the first mixed CuPt monolayer is small and of amplitude 0.03 +/- 0.04 Angstrom with Pt rippled outwards towards the solid-vacuum interface.
10.1016-S0040-6031(02)00500-2	-1		The entire phase diagram of the Cu-In system was investigated using differential scanning calorimetry (DSC), powder X-ray diffraction (XRD). metallography and electron probe microanalysis (EPMA) studies. The results indicate the existence of a solubility region of In in Cu with the limit of the solid solution at 5.20 at% In at 400 degreesC and of six intermediate phases, the three low-temperature phases delta, eta and Cu11In9, and the three high-temperature phases gamma, eta' and beta. The boundaries of each phase were defined with respect to temperature and composition.
10.1016-S0040-6090(00)01042-7	4	transformation; martensite; martensitic; phase; shape; beta; memory; shape memory; temperature; temperatures; martensitic transformation; gamma; transformation temperatures; effect; thermal	Ti-Ni and Ti-Ni-Cu shape memory alloy thin films were made by rf magnetron sputtering. The shape-memory behavior associated with the martensitic transformation was measured under various constant applied stresses during thermal cycling from below Mf to above Af. Each strain vs, temperature curve revealed typical single stage deformation behavior. A model based on the thermodynamics of irreversible processes was used for the simulation of the shape-memory behavior of the thin films. Phenomenological material constants that were requisite to the modeling were obtained experimentally. The strain vs. temperature curves calculated by the thermodynamic model, and the experimentally obtained curves, showed a reasonable correspondence in the higher applied stress region, while a large disagreement between them was observed in the lower applied stress region; i.e. the transformation strain was higher in experimental data than in the corresponding calculated data in the lower applied stress region. The present phenomenological macroscopic model was efficient for mean and high stresses where one or two variants were activated per grain. With lower stresses where four or more variants were activated per grain, our interaction energy expression was not sufficient to describe the multiple interactions between austenite and martensite platelets and between martensite variants.
10.1016-S0040-6090(97)00487-2	-1		Electromigration in isolated 0.25-1. 0 mu m wide pure Cu fine lines has been investigated using both resistance and edge displacement techniques in the sample temperatures range 221-394 degrees C. The Cu lines, sandwiched with a top and bottom Ta layer, were 200 mu m long and were connected to underlying W bars on each end of the Cu line. Transmission electron microscopy revealed that the microstructures of the 1 and 0.25 mu m wide lines were polycrystalline and bamboo-like grain structures, respectively. During electromigration, voids formed at the cathode end while hillocks,stew at the anode end. The failure lifetimes were correlated to the sizes of voids formed in the vicinity of the cathode end of the line, and a distribution of multiple failure modes was found. A low value of electromigration activation energy, 0.81 +/- 0.05 eV, and a Linear relationship between failure lifetime and metal linewidth were found, despite the fact that these narrow lines were close to a perfect bamboo-like grained structure. These results suggest that the mass transport of Cu during electromigration primarily occurs along the sidewall surfaces of the lines. (C) 1997 Elsevier Science S.A.
10.1016-S0043-1648(01)00843-2	-1		The wear behavior of aged Cu-Cr-Zr alloys dry sliding against a brass counterface were investigated on a pin-on-disk wear tester under electric current conditions. The worn surfaces of the aged Cu-Cr-Zr alloys were analyzed by scanning electron microscope (SEM) and energy dispersive X-ray spectrum (EDS). The results indicated that the aging treatments had an effect on the microstructure, hardness and wear resistance of Cu-Cr-Zr alloy. At the constant current density, the wear rate of Cu-Cr-Zr alloy decreased with aging temperature, and reached the minimum at 500 degreesC, then increased with further increasing aging temperature. An appropriate aging treatment may improve the wear resistance of the materials due to the formation of fine, dispersive and coherent precipitates within the matrix. An increase in electrical current resulted in an increase in wear rate of both the Cu-Cr-Zr alloy pin, and the brass disk. Adhesive wear, abrasive wear and are erosion were the dominant mechanisms during the electrical sliding processes. Compared with commercially used Cu-Ag alloy wire (CTHA 110) under the same test conditions, the Cu-Cr-Zr alloy treated at 500 degreesC for 2 h exhibited much better wear resistance.
10.1016-S0043-1648(03)00072-3	16	wear; composite; composites; powders; milling; particles; powder; wt; sliding; friction; hardness; matrix; mechanical; surface; properties	Copper-based sintered composites produced by powder metallurgy processes are now widely used in tribological engineering parts, e.g. bearings and bushes. Also composites based on copper-tin alloys containing a solid lubricant have been developed as self-lubricating materials under extreme conditions of load, atmosphere and temperature. It is well known that the addition of graphite serves to reduce friction and wear in copper-tin alloys. However it should be noted that the addition of graphite or molybdenum disulfide (MoS2) has an adverse effect on the composites' mechanical properties. In this paper, the lubricant graphite and MoS2 Powders were coated with Cu to reinforce their bonding to the Cu particles in the composites during sintering. The hardness, microstructure and bending strength of the sintered specimens were examined. The friction and wear properties of the materials were estimated by a cylinder-on-plate wear machine under dry conditions at room temperature in air. Although mechanical properties of the composites decreased with increasing amount of added graphite or MoS2, the use of Cu-coated lubricant powders improved the bending strength . Graphite was very effective in reducing the wear and friction of the composites. Particularly, the 40 vol.% graphite composites showed a very low coefficient of friction of 0.15. Furthermore, the wear rate of the Cu-coated graphite specimens was much lower than that of the uncoated graphite specimens. By contrast, the wear rates of the MoS2 composites increased considerably with the amount of MoS2 addition. This behavior is thought to be due to the absence of MoS2 and the presence of brittle CuMo2S3 compounds in the sintered composites.
10.1016-S0043-1648(96)07368-1	16	wear; composite; composites; powders; milling; particles; powder; wt; sliding; friction; hardness; matrix; mechanical; surface; properties	The Cu-15 vol.% Cr in situ composite is a promising material for the electrical contacts in high current devices, since it has an excellent combination of mechanical strength and electrical/thermal conductivity. The electrotribological behavior of Cu-15 vol.% Cr was studied using a modified pin-on-disk tester with an electrical current applied across the sliding interface. The Cu-15 vol.% Cr pins were slid against a hardened AISI 52100 steel disk under dry ambient conditions. Coefficient of friction, wear rate and bulk temperature of the composite pins were evaluated as a function of electrical current, normal pressure and sliding speed. The microstructural change in the composite due to electrical sliding was related to the electrotribological behavior. Within the studied range of electrical current, normal pressure and sliding speed, the coefficient of friction and the wear rate decreased wifh increasing electrical current, whereas the bulk temperature increased. A deformed subsurface layer was identified in the composite after electrical sliding. The thickness of the subsurface layer decreased with increasing electrical current. The surface layer, containing refined structure,wear debris and back transferred materials from the steel disk, had a high level of microhardness.
10.1016-S0142-1123(01)00189-X	6	grain; deformation; strain; strength; dislocation; cu-; tensile; size; ecap; grain size; sfe; ductility; hardening; high; stress	Low-cycle fatigue behavior of [1 1 3] double-slip oriented Cu-Fe alloy single crystals with and without precipitated f.c.c. gamma-Fe particles were examined under plastic-strain-controlled fatigue tests and compared with that of single-slip oriented crystals such as [4 1 9]. Although the gamma-Fe particles are coherent and shearable, no cyclic softening was observed in all the particle bearing specimens. The cyclic stress-strain curves of the [1 1 3] crystals show a plateau region similar to those in the [4 1 9] crystals. On the other hand, shear stress amplitude increased monotonically with increase in shear strain amplitude on solution treated specimens. Dislocation microstructures characteristic of cyclic deformation were more clearly developed in the [1 1 3] crystals. Magnetic measurement of fatigued specimens revealed that more particles had transformed martensitically into b.c.c. alpha-Fe in the [1 1 3] crystals than in the [4 1 9] crystals. The above results can be understood reasonably if orientation-dependent deformation and transformation characteristics are taken into account.
10.1016-S0142-1123(02)00005-1	6	grain; deformation; strain; strength; dislocation; cu-; tensile; size; ecap; grain size; sfe; ductility; hardening; high; stress	Copper polycrystals, single crystals and bicrystals with dispersed spherical SiO2 particles were cyclically deformed at temperatures between ambient temperature and 673 K. All the crystals showed typical cyclic creep behavior. Though the polycrystals tended to show longer life than that of the single crystals at lower temperatures under higher stress amplitude, the life became shorter than that of the single crystals, especially at higher temperatures under applied low stress amplitude. The stress amplitude, where the life of the polycrystal becomes shorter than that of the single crystal, became lower as the temperature increased. At such a stress amplitude (transient stress amplitude), dominant cracking and propagation mode changed from transgranular to intergranular. The fracture mode of the bicrystals also changed sharply at the critical stress amplitude from transgranular to intergranular with increasing temperature. The observed fracture-mode change at the critical stress amplitude is discussed in relation to grain-boundary sliding and grain-boundary cracking.
10.1016-S0151-9107(03)00104-1	4	transformation; martensite; martensitic; phase; shape; beta; memory; shape memory; temperature; temperatures; martensitic transformation; gamma; transformation temperatures; effect; thermal	Ageing phenomena in the martensitic phase beta'(1) of Cu-Al-Ni base shape memory alloys (SMAs) are rather slow; the visible outcome is a progressive evolution of the characteristics of the martensitic double left right arrow parent phase transformation. During thermal cycling, these phenomena induce only a small stabilization of the martensitic phase. However, the modification in the characteristics of the transformation on heating and cooling after ageing in the beta(1) phase are more complex. From DSC measurements, it was shown that a precipitation process occurs between 220 and 370 degreesC. When samples initially in the quenched state are cycled, several evolutions during ageing change the shape memory capability by a more or less important degradation of the thermoelastic character of the martensitic transformation.
10.1016-S0167-577X(00)00083-5	-1		A modified first-order kinetic law, which takes into account defect decay during an ordering process, was employed to predict the short-range-order (SRO) kinetics of a quenched and quenched-deformed Cu-10 at% Zn alloy in conjunction with experiments performed by differential isothermal calorimetry (DIC). Effective activation energy values for point defect migration, and its temperature dependence, strongly suggest the contribution of bound vacancies to the ordering process. An estimate of 94.2 kJ mol(-1) was made for the activation energy for solute-vacancy migration by applying an effective rate constant.
10.1016-S0167-577X(02)01120-5	-1		The structures of molten Cu-23% Sn alloy at different temperatures have been determined by using a high-temperature Xray diffractometer. It has been found that there exist not only short-range order (SRO) structure but also medium-range order (MRO) structure in the molten alloy. The medium-range order structure in the alloy melt is a function of temperature. There exist obvious medium-range order structure at the range of temperatures from 900 to 1200 degreesC. The medium-range order structure disappears when the temperature reaches 1300 degreesC. The temperature dependence of the dynamic viscosity of the alloy melt has been measured using a torsional oscillation viscometer. It has been found that there is an abnormal change in the relationship between the temperature and the viscosity of the alloy melt. The abnormity change is consistent with the transformation from medium-range order to short-range order in the alloy melt.
10.1016-S0167-577X(03)00005-3	4	transformation; martensite; martensitic; phase; shape; beta; memory; shape memory; temperature; temperatures; martensitic transformation; gamma; transformation temperatures; effect; thermal	Effects of hydrostatic pressure on the martensitic phase transformation, thermal conduction and thermodynamic parameters of Cu-13 wt% Al-4 wt% Ni alloy have been investigated. The pressure dependence of M-S, M-f; A(s) and A(f) temperatures are interpreted in the frame of the study. The pressure dependence of the dissipative energy terms of the martensitic and reverse transformation has been separated and analyzed. It is found that the transformation temperatures of the shape memory alloy increase with applied stress. The thermal conductivity of the alloy was measured as a function of pressure. The thermodynamic parameters such as enthalpies, entropy and specific heat capacity of the alloy were determined.
10.1016-S0167-577X(03)00365-3	-1		Copper matrix composites reinforced with 10 vol.% SiC particles with or without nickel coating were fabricated by powder metallurgy plus hot extrusion method. The results show that the densification, bulk hardness, ultimate flexural strength and ductility were improved by the electroless plating on the reinforcement, while the electrical conductivity remains at a fairly high level as the uncoated one. The nickel coating modifies the interface structural model and is effective in passing load between the matrix and the reinforcement. By lessening the extent of interfacial debonding, the coating changes the fracture and wear mechanism of the composites, therefore improving the mechanical properties and wear resistance.
10.1016-S0167-8442(99)00050-6	4	transformation; martensite; martensitic; phase; shape; beta; memory; shape memory; temperature; temperatures; martensitic transformation; gamma; transformation temperatures; effect; thermal	The basic properties of pseudoelasticity of Cu-Al-Ni single crystal are studied to analyze the morphology associated with the formation and evolution of martensite and the shape memory recovery process at different temperatures. Use is made of a multifunctional macro-micro moire interferometry measurement system. The beta(1) to beta(1)' phase changes are identified with the stress-induced transformation of a Cu-13.7%Al-4.18%Ni (wt%) alloy. The invariant plane between the martensite and the parent phase is shown directly by fringe patterns. It is found that martensite appears in the shape of bands or thin plates on the surface of the specimen. The formation of martensite is a very rapid process and martensite 'jumps' out until the specimen is completely transformed into a single variant. The results reveal the mechanism and process of stress-type and temperature-induced martensitic transformation.
10.1016-S0168-583X(01)01180-6	-1		The terminal solubility of Pb in Cu is extremely low and does not exceed 0.09 at% at 875 K. Ion implantation of lead ions at 100 keV into Cu single crystals produces metastable solutions. Annealing of the samples causes redistribution of the implanted atoms to equilibrium or near-equilibrium aggregate states which may be reflected in a change in the type of impurity lattice location in the host matrix. We have studied the effect of annealing on single crystalline Cu implanted at temperatures around 375 K with Pb to a concentration of a 1-2 at%. Rutherford backscattering/channeling analysis and transmission electron microscopy of the as-implanted samples have shown that the implanted Pb forms a Supersaturated solid solution with a major fraction of the Ph atoms located on substitutional sites in the host lattice or in very small clusters. At higher annealing temperatures up to 870 K more than half of the lead is lost by outdiffusion and the remaining fraction forms nanometer-sized crystalline inclusions by cooling to room temperature. Melting and solidification temperatures of the inclusions have been followed by in situ channeling measurements. (C) 2002 Published by Elsevier Science B.V.
10.1016-S0168-583X(99)00959-3	-1		In the present work Cu-3 Au(1 0 0) alloy surface has been investigated with low energy ion scattering at temperatures below and above the bulk order-disorder transition temperature. The trajectories of Ar+ low energy ions scattered from atomic chains on the surface of Cu-3 Au(1 0 0) along (I 0 0) and (1 10) directions were computer simulated. The dependencies of the energy of scattered ions E on the scattering angle theta and corresponding angular distributions were calculated. It has been shown that a comparison of the angular and energy distributions of ions scattered from the surface of an alloy in the process of ordering with similar distributions for pure targets made up of the alloy components permits a conclusion that two or more neighboring atoms in an alternating sequence are of the same species. The results obtained can be used to study short-range order in alloys undergoing ordering.
10.1016-S0168-9002(01)01058-0	-1		The interest to systems containing copper oxide is connected with the problem of high-temperature superconductivity because of the closeness of its basic physical properties and properties of superconductor mother Cu-compounds. In this work, EXAFS study of the Cu0.2Mg0.8O Compound is presented. A new iterative algorithm of the solution of ill-posed problem on determining three partial pair correlation functions from one EXAFS-data set near the Cu K-edge is described. The results of X-ray scattering study of a given sample show a presence of a single phase with the MgO structure and a lattice parameter of 4.219 Angstrom instead of 4.208 Angstrom for pure MgO. From the EXAFS investigations, we find the local distortion of the lattice. We revealed that the short range order differs both from a hypothetical alloy with the MgO structure and from copper oxide.
10.1016-S0169-4332(00)00627-9	-1		The aim of this paper is to present results concerning the morphology, structure, mechanical and electrical characteristics of the new proposed Cu-Sn metallurgical alloy, which may be used in electronic joins. By proper choice of process temperature and pressure. Cu coated surfaces are soldered using Sn as pre-form. The main results achieved indicate that the formation of Cu3Sn phase begins at a temperature of about 473 K and that the Sn thickness (d(Sn)) needed is slightly above 7 mum. Due to join wettability, higher temperatures (between 523 and 573 K) and d(Sn) above 35 mum are required to form joins within the specifications of the electronic industry. (C) 2000 Published by Elsevier Science B.V.
10.1016-S0169-4332(01)00211-2	-1		The occurrence of an Ag layer on top of a Cu (111) substrate can result from either deposition of Ag atoms on a Cu (111) substrate or from strong segregation at the (111) surface of a dilute Cu (Ag) alloy, Quenched molecular dynamics simulations within many-body tight-binding potentials show that two structures compete at T = 0 K. The first one corresponds to a Moire structure built by the superposition of an hexagonal Ag (111) layer on top of a Cu (111) substrate, the lattice parameter of the Ag layer being very near of the bulk Ag one. The second structure involves constitutive vacancies forming a triangular loop of dislocation in the first Cu underlayer. We show here that increasing temperature slightly favours the Moire structure along a free energy criterion, as a result of a complex interplay between internal energy and vibrational entropy. This indicates that the experimentally observed transition between the Moire structure at low temperature and the triangular one at higher temperature has probably a kinetic origin and is not a true equilibrium phase transition. (C) 2001 Published by Elsevier Science B.V.
10.1016-S0169-4332(02)01526-X	-1		The Cu-Mo alloy film with positive beat of mixing was prepared by ion beam assisted deposition (IBAD) technique. When the energy of Ar+ ions was 2 keV during IBAD, metastable bcc Cu was formed in the Cu20Mo80 film. A Mo-based bcc supersaturated solid solution was obtained within the composition range of 0-50% Cu fraction. An fcc supersaturated solid solution was also formed around the composition of 15 at% Mo. The formation mechanisms of the metastable alloy phases were discussed in terms of the process far from equilibrium.
10.1016-S0169-4332(03)00630-5	-1		This paper provides two examples of computer simulation of interfacial phenomena, performed for the purpose of aiding the progress of experimental studies. In both cases, the modeling was performed by Monte Carlo methods, in conjunction with semi-empirical density functional type potentials. In the first example, simulations of compositional surface phase transitions in Cu-Ag alloys were performed. These simulations were very useful in guiding experiments away from (1 0 0)- to (I I I)-oriented Cu-Ag single crystals, where the sought-after transitions were eventually observed. In the second example, modeling was used to obtain quick estimates of the absolute values of Pb/Al interfacial energies. When measurements were eventually performed, the computed values were found to overestimate the measured Pb/Al(l 1 1) interfacial energy by about a factor of 3. Beyond those two examples, what we have learned from our own efforts at modeling alloy surface and interface phenomena with semi-empirical density functional type potentials, is that this type of modeling rarely produces quantitatively reliable predictions of compositions or energies. Nevertheless, some of the qualitative features of the predictions can often provide valuable insights for planning or interpreting experiments.
10.1016-S0254-0584(00)00296-0	4	transformation; martensite; martensitic; phase; shape; beta; memory; shape memory; temperature; temperatures; martensitic transformation; gamma; transformation temperatures; effect; thermal	The cellular precipitation in Cu-9 wt% Sb alloy is studied with optical and scanning electron microscopy and X-ray diffraction. The first goal of the present paper is to give an overview of the different sites of discontinuous precipitation as grain boundaries, different interface boundaries and dislocations. Moreover, a coarser lamellar spacing is first observed in the cellular product of discontinuous precipitation before the formation of a finer cell at the reaction front of the coarser one. The second goal concerns the mechanism of dissolution which is discontinuous at relatively lower temperature and continuous at higher one.
10.1016-S0254-0584(01)00411-4	-1		The amorphous Cu-Ni-Zr alloys were successfully synthesized by mechanical alloying mixtures of pure crystalline Cu, Ni and Zr powders with SPEX high-energy ball mill. These ranges are similar to those for amorphous alloys produced by melt-spinning techniques. The structure and thermal stability of these alloys were analyzed by X-ray diffraction and differential scanning calorimeter. Several amorphous alloy samples were found to exhibit a wide supercooled liquid region before crystallization. The temperature interval of the supercooled liquid region defined by the difference between T-g and T-x, i.e. DeltaT(x) (= T-g-T-x), is 34 K for Cu10Zr60Ni30, 48 K for Cu20Zr60Ni20, 78 K for Cu40Zr55Ni5, 81 K for Cu50Zr35Ni15, 61 K for Cu50Zr40Ni10 and 64 K for Cu50Zr45Ni5.
10.1016-S0254-0584(02)00348-6	-1		In the as-quenched condition, the microstructure of the Cu-14.2Al-15.0Ni alloy was D0(3) phase containing extremely fine L-J precipitates. Since both fine D0(3) domains with a/2(100) anti-phase boundaries (APBs) and small B2 domains with a/4(111) APBs could be observed, the D0(3) phase existing in the as-quenched alloy should be formed by an A2 --> B2 --> D0(3) continuous ordering transition during quenching. It is worthwhile to note that the a/4(111) APBs have never been observed by other workers in the Cu-Al-Ni ternary alloys before. When the as-quenched alloy was aged at temperatures ranging from 400 to 1000 degreesC for longer times, the phase transformation sequence as the aging temperature increased was found to be (alpha + B2 precipitate) --> (B2 + B2 precipitate) --> B2 --> A2. This transformation has also never been observed by other workers in the Cu-Al-Ni ternary alloys before.
10.1016-S0254-0584(02)00411-X	2	corrosion; surface; film; electrochemical; films; spectroscopy; layer; current; solution; potential; resistance; composition; x-ray; ions; showed	The corrosion behaviour of modified Al-brass (MA72) and Cu10Ni alloys was investigated in 3.5% NaCl in absence and presence of different concentrations of sulfide ions. The results indicated that the Cu10Ni alloy demonstrated better corrosion resistance in 3.5% NaCl solution. The corrosion of the alloys has increased in presence of sulfide ions. The increase of sulfide ions (500, and 1000 ppm) resulted a pitting corrosion in case of Cu10Ni and intergranular corrosion of Al-brass. The detrimental effect of sulfide on the corrosion resistance increases with the increase of sulfide ion concentrations. The results of the weight variations and potentiostatic polarization are in agreement with the potential-time measurements that the sulfide ions in polluted seawater promotes the corrosion of Cu10Ni than Al-brass. The formation of Cu2S interferes with the protecting oxide film and reduces its corrosion resistance.
10.1016-S0254-0584(02)00451-0	-1		Age hardening in Cu-3.2M-0.75Si (wt%) alloy at 723 K is studied. An immediate increase of the yield strength characterizes the aging of the alloy. This is followed by the regions of constant yield strength and further by a peak. The microstructure of the alloy was studied by means of transmission electron microscope (TEM) and X-ray diffraction. Spinodal decomposition takes place followed by nucleation of the ordering coherent (Cu Ni)(3)Si particles, further annealing coherent delta-Ni2Si nucleated within the (Cu Ni)(3)Si particle. Any change of the yield strength can be described by an adequate change of the structure in the sample. The nature of the aging curves with a plateau is discussed. The formulas of Ashby and Labusch can be used to explain the precipitation.
10.1016-S0254-0584(03)00275-X	2	corrosion; surface; film; electrochemical; films; spectroscopy; layer; current; solution; potential; resistance; composition; x-ray; ions; showed	Linear potential sweep voltammetry was used to characterize the metal oxides formed at the surface of brass (Cu-10Zn) foils exposed to a gliding-arc-humid-air plasma. This study confirmed the formation of copper and zinc oxides (i.e. Cu2O, CuO, and ZnO). The electrochemical reduction curves in aqueous solutions of the different brass samples showed that copper and zinc oxides were characterized by their cathodic peaks. The reduction potentials of the oxides varied with the exposure time to the plasma at fixed working conditions. The analysis of the voltammetry curves showed that the initial oxide layer was formed in majority by the precursor oxide CuxO (x > 4) and Cu2O. The oxidation of Cu(I) oxide (CuxO and Cu2O) lead to the formation of CuO. When the CuO layer was extensively grown, the ZnO oxide began to grow. A mechanism was proposed for the reduction of thin films containing Cu2O, CuO and ZnO oxides formed at the surface of the sample.
10.1016-S0257-8972(02)00008-7	2	corrosion; surface; film; electrochemical; films; spectroscopy; layer; current; solution; potential; resistance; composition; x-ray; ions; showed	Cu/Ni multilayer coatings prepared by RF/DC magnetron sputtering process were characterized using x-ray diffraction (XRD), nanoindentation and atomic force microscopy (AFM) techniques. Films deposited under certain deposition conditions showed the appearance of satellite reflections around the principal reflections in the XRD data, indicating the formation of superlattice structure. Nanohardness measurements were performed on the films prepared under different deposition conditions, e.g. modulation wavelength (Lambda), copper to nickel thickness ratio and substrate temperature (T-s). Nanohardness data revealed that the hardness was enhanced by a factor of similar to2.5 times that of the rule-of-mixtures value. This enhancement in hardness occurred over a limited range of Lambda. The results indicated that the hardness also depends on the copper to nickel thickness ratio and for t(Co)/t(Ni)similar or equal to0.30 the films exhibited a maximum hardness. The hardness increased almost linearly with substrate temperature up to 200 degreesC and got saturated at 250 degreesC. No considerable change in the hardness was observed after vacuum annealing of the coatings. Imaging of the residual imprints by AFM revealed pile-up formation after indentation. The extent of pile-up, a measure of plastic flow of the material, was dependent on the preparation conditions of the multilayer coatings.
10.1016-S0257-8972(02)00139-1	2	corrosion; surface; film; electrochemical; films; spectroscopy; layer; current; solution; potential; resistance; composition; x-ray; ions; showed	The effect of the presence of tartrate additive on the chemical stability of a Cu-Sn acid bath was evaluated. It was observed that this additive hinders decomposition of the Cu/Sn deposition bath with storage time, since the decrease in electrochemical efficiency was attenuated. In addition, it was observed that optimal galvanostatic deposition with or without tartrate occurs at approximately 11 mA cm(-2). However, in the presence of tartrate the deposition charge was lower, leading to lower energy consumption. SEM analysis showed that the tartrate added to the plating bath caused a marked change in the morphology of the Cu/Sn films obtained gal vanostatic ally.
10.1016-S0261-3069(00)00019-4	4	transformation; martensite; martensitic; phase; shape; beta; memory; shape memory; temperature; temperatures; martensitic transformation; gamma; transformation temperatures; effect; thermal	The gamma-precipitates in Cu-Zn-Al alloys, trained by the stabilization of the stress induced martensite (SSIM) method, have been studied. After the SSIM treatment, it was found that small gamma-precipitates in the beta-austenite are ellipsoidal, with a large strain field oriented in the same direction; while in the martensite the gamma-precipitates changed their shape from ellipsoid to spheroid, and relaxed their strain fields. In order to check whether the strain field of the gamma-precipitates is capable of producing a thermoelastic martensitic transformation, an in-situ observation, by heating a sample holder in TEM, was performed. It was found that during heating over a temperature A(s), the gamma-precipitates with a spherical shape in the martensite recovered their strain field and elliptical shape. During cooling, the strain field of the gamma-precipitates disappeared again. It was proposed that the strain field of the gamma-precipitates, trained by the SSIM method, plays an important part in the thermoelastic martensitic transformation, and presents two-way shape memory effects.
10.1016-S0304-8853(00)00855-6	9	magnetic; magnetization; magnetoresistance; temperature; superparamagnetic; annealing; gmr; field; magnetic properties; ferromagnetic; granular; samples; magnetic field; melt-spun; particles	The Co-59 nuclear magnetic resonance technique was used to investigate a set of melt-spun Cu85Co15 ribbons heat-treated at different temperatures. In the as-cast sample the grains are very small and the contribution of the surface prevails over the bulk. Heat treating the samples, the contribution of the bulk FCC Co grows and for temperatures around 500 degreesC, a small amount of HCP Co seems also to be present.
10.1016-S0304-8853(00)00944-6	9	magnetic; magnetization; magnetoresistance; temperature; superparamagnetic; annealing; gmr; field; magnetic properties; ferromagnetic; granular; samples; magnetic field; melt-spun; particles	Magnetization measurements were performed on Cu80Fe4Ni16 melt-spun alloys thermally treated at several temperatures up to 600 degreesC. The magnetization curves were fitted using the sum of paramagnetic and ferromagnetic contributions, where the paramagnetic component is given by a Langevin function weighted by a lognormal moment distribution. The average moment of superparamagnetic clusters was determined, ranging from 31 to 11000 mu (B), corresponding to average cluster sizes between 0.9 and 6.2 nm.
10.1016-S0304-8853(00)01101-X	-1		We show that CuxNi1-x alloy films and CuxNi1-x/CuyNi1-y multilayers of arbitrary composition maybe grown by electrodepositing well-defined sub-monolayer quantities of Cu and Ni in alternation. The magnetic properties of the CuxNi1-x films provide evidence of Ni clustering in alloys prepared by this method. The dependence of the clustering on the Ni deposition potential suggests that a form of self-organization takes place. For CuxNi1-x/CuyNi1-y multilayers, up to third-order superlattice satellite peaks are seen in high-angle X-ray diffraction experiments.
10.1016-S0304-8853(01)00279-7	9	magnetic; magnetization; magnetoresistance; temperature; superparamagnetic; annealing; gmr; field; magnetic properties; ferromagnetic; granular; samples; magnetic field; melt-spun; particles	The magnetic interactions between the nanograins in heterogeneous granular Cu-(SmCo5)-Fe ribbons were evaluated with a classical mean field model to obtain the exchange coupling as well as the magnetic moment per nanoparticle. The samples were subjected to various thermal treatments and a significant magnetoresistive effect was obtained when the optimal annealing conditions had been achieved.
10.1016-S0304-8853(01)00363-8	-1		The effects of Ni and rare earth (La, Ce, Nd, Dy, Tb) co-addition on GMR of the melt-spun Cu-Co alloys are investigated. The results indicate that Ni addition can increase the GMR of the melt-spun Cu-Co ribbons. The reasons are that Ni addition can restrain the liquid phase separation occurring at high temperature and increase the density of the fine magnetic Co-rich precipitates during the annealing process. Light rare earth, such as Ce and La, can further enhance GMR of the melt-spun Cu-Co-Ni ribbons. Among these elements, Cc is the most effective. However, heavy rare earth additions result in a GMR decline of the melt-spun Cu-Co-Ni ribbons. It is discovered that there exists an optimal addition quantity for Cc. Excessive Ce addition could result in a GMR decline as well. The reasons for the GMR improvement of Re addition are: role of purifying melt, promoting precipitates process and enhancing the magnetic susceptibility of the fine Co-rich precipitates.
10.1016-S0304-8853(01)00413-9	2	corrosion; surface; film; electrochemical; films; spectroscopy; layer; current; solution; potential; resistance; composition; x-ray; ions; showed	High quality Cu-Co alloy films with excellent metallic luster have been electrolytically deposited directly onto n-Si (100) substrate, thereby eliminating the need of a conducting seed layer, which is otherwise required when the films were grown on insulating substrates (Al2O3). The as-deposited Cu-Co films exhibit relatively higher magnetoresistance (MR) in comparison with the as-deposited films on Al2O3 under identical conditions. The observed increase in MR could be attributed to the reduced substrate current shunting. The MR further improves to 2.67% (at H = 10 kOe) with vacuum annealing (at 425 degreesC for 30 min) of the films on Si. This has been ascribed to the separation of Cu and Co phases resulting in a magnetic granular nanostructure. This value of MR of annealed films on Si is, however, lower in comparison with the value obtained for annealed films deposited on Al2O3. Glancing angle X-ray diffraction (GAXRD) has revealed the formation of copper silicide in these samples, which is responsible for the lower value of MR. Thus we have observed good MR with a copper silicide host matrix.
10.1016-S0304-8853(01)00593-5	9	magnetic; magnetization; magnetoresistance; temperature; superparamagnetic; annealing; gmr; field; magnetic properties; ferromagnetic; granular; samples; magnetic field; melt-spun; particles	The effect of temperature (10-300 K) and high hydrostatic pressure (7 kbar) on the magnetic properties of nanometersized Co-particles embedded in the Cu-matrix was studied. The analysis of the experimental results showed that the system displayed mictomagnetic behavior. The observed changes of coercivity with temperature and pressure were interpreted taking into account also the determined distribution of the blocking temperatures of the Co-particles. The influence of temperature and pressure on the present inter-particle interactions is discussed.
10.1016-S0304-8853(01)00976-3	-1		We show that nanogranular materials exhibiting moderate giant magnetoresistance can be prepared by mixing nanocrystalline powders of copper and cobalt. having grain size in a range of 40 nm. Nanopowders are mixed in various compositions using planetary ball mill and then sintered. Magnetoresistance (MR) is measured at 42 K and structural analysis are performed using X-ray diffraction. Variation of MR observed for various mixing conditions and cobalt contents are examined and discussed. This processing technique opens new perspectives for the fabrication of MR granular materials. (C) 2002 Elsevier Science B.V. All rights reserved,
10.1016-S0304-8853(02)00841-7	6	grain; deformation; strain; strength; dislocation; cu-; tensile; size; ecap; grain size; sfe; ductility; hardening; high; stress	Secondary recrystallization. structures of 100% were obtained from nitrided primary specimens with different annealing temperatures before cold rolling and with various Cu contents. However, magnetic induction B-10 varied between 1.58 and 1.95 T. The evolution mechanism of the wide range of B10 was interpreted due to a change in the types of grain boundaries that became specifically mobile during secondary recrystallization.
10.1016-S0304-8853(97)00519-2	-1		Saturation magnetization M-s and Curie temperature T-c for amorphous CuGd alloys are investigated in order to understand the rule of electrons which contribute to magnetic properties. The magnetic moment per Gd atom is nearly equal to 7 mu B assuming that Cu is nonmagnetic and the enhancement of M-s through outer-shell electrons is found to be suppressed. The values of exchange interactions between Gd and Gd atoms are found to be nearly equal to that for a-FeGd system.
10.1016-S0304-8853(97)00620-3	-1		Controlled microstructured Cu-Co thin films have been fabricated by pulsed-laser ablation during which the target was rotated between 10 and 32 rpm. The samples exhibit giant magnetoresistance after the films are annealed. The films obtained at low rotation velocities require a higher magnetic field (approximate to 0.15 T) to achieve the maximum resistance in the perpendicular MR as compared to 0.05 T for the parallel MR. On the other hand, the films obtained at higher rotation velocities require quantitatively similar magnetic fields in both orientations, about 0.05 T. This effect is discussed in terms of shape and crystalline anisotropy of magnetic nanoparticles.
10.1016-S0304-8853(98)00660-X	-1		Room temperature measurements of magnetisation and giant magnetoresistance were performed on heterogeneous CuCo thin films produced with different thickness by means of RF sputtering. Average particle size, particle size distribution, volume fraction of particles were obtained from magnetisation curve analysis. A correlation among moments was found in all examined systems, depending on him thickness.
10.1016-S0304-8853(98)00822-1	9	magnetic; magnetization; magnetoresistance; temperature; superparamagnetic; annealing; gmr; field; magnetic properties; ferromagnetic; granular; samples; magnetic field; melt-spun; particles	Melt-spun Cu80Co10Fe10 ribbons are shown to exhibit a nanogranular structure with magnetic alpha-Fe(Co) grains segregated from the Cu-rich matrix after appropriate annealing. The Cu matrix purification as well as the magnetic properties of the alpha-Fe(Co) grains existing in a range of sizes are studied using X-ray diffraction, Mossbauer spectrometry and magnetic measurements. There is an optimum annealing for obtaining a high magnetoresistive effect.
10.1016-S0304-8853(99)00208-5	9	magnetic; magnetization; magnetoresistance; temperature; superparamagnetic; annealing; gmr; field; magnetic properties; ferromagnetic; granular; samples; magnetic field; melt-spun; particles	The structural and magnetic properties of Fe particles grown in a Cu matrix by annealing a precursor alloy of composition Cu97Fe3 are discussed. Structural characterization suggests that all segregated Fe particles are BCC-type. However, AC susceptibility and hysteresis loops display short-range antiferromagnetic correlations and a spin glass-like behavior. The former is analyzed in terms of the effects occurring at the particle surface, while the latter is associated with the Fe spins diluted in the Cu matrix.
10.1016-S0304-8853(99)00214-0	9	magnetic; magnetization; magnetoresistance; temperature; superparamagnetic; annealing; gmr; field; magnetic properties; ferromagnetic; granular; samples; magnetic field; melt-spun; particles	Supersaturated Cu80Fe10Co10 alloy with a grain size of about 20 nm confirmed by X-ray diffraction was prepared by mechanical alloying from Cu, Fe and Co (-80 mesh, 99.9%) powders. Both room temperature field-dependent and temperature-dependent (FC and ZFC) DC magnetization data, and temperature-dependent AC susceptibility data measured at various frequencies hint at the simultaneous presence of ferromagnetic and superparamagnetic clusters in this alloy. Room temperature Mossbauer results suggest that the Fe atoms are located in a paramagnetic environment, thus the magnetic clusters should be composed mainly of Co atoms.
10.1016-S0379-6779(97)81044-2	-1		Cu(DCNQI)(2) can be switched from a metallic state to an insulating one by external pressure or internal (chemical) pressure in a very abrupt manner. We have used the pronounced anticoincidence of the ESR-intensity and the conductivity to study the processes at the phase transitions in detail by measuring simultaneously the ESR and conductivity as a function of T and under pressure. We have a break down of the conductivity if 20% of the total volume is switched into ESR-active areas. This is interpreted by a percolation Limit between the still conducting (ESR-silent) domains. Including individual internal pressure values for differently deuterated Cu(DCNQI)(2) salts and alloys between deuterated and undeuterated DCNQI, a general phase diagram can be given.
10.1016-S0749-6419(00)00005-X	4	transformation; martensite; martensitic; phase; shape; beta; memory; shape memory; temperature; temperatures; martensitic transformation; gamma; transformation temperatures; effect; thermal	The paper presents a macroscopic description for the simulation of the two way shape memory effect (TWSME) of shape memory alloys (SMA), and is an extension of a previous work dealing with the global thermomechanical behavior of SMA. The model is set in the framework of the thermodynamics of irreversible processes. Two internal variables are taken into account : the volume fraction of self-accommodating (pure thermal effect) and oriented (stress-induced) product phase. A term dedicated to the modeling of the trained SMA is added to the specific free energy derived for the non-trained SMA. This term phi(ed), depends on the thermomechanical procedure of training submitted to the sample. In the present case, it accounts for the stress tensor sigma(ed) applied during thermal cycling. The parameters of the model have been identified for a Cu Zn-Al SMA, and the simulated results show good agreement with experiments.
10.1016-S0749-6419(00)00010-3	4	transformation; martensite; martensitic; phase; shape; beta; memory; shape memory; temperature; temperatures; martensitic transformation; gamma; transformation temperatures; effect; thermal	This paper. deals with the influence of martensitic transformation latent heat on the superelastic behaviour modelling. Exothermic and endothermic effects are responsible for a strong evolution on the temperature field inside the material that modifies its mechanical response. This is responsible for a strain late effect that is taken into account by introducing a coupling equation between the production rate of martensite and the temperature change, into a micro macro modelling of the superthermoelastic behaviour with the assumption that the temperature field remains uniform but different to the test temperature imposed. Numerical simulations so obtained show a good agreement with experimental results performed on Cu-based superelastic alloys. (C) 2000 Published by Elsevier Science Ltd.
10.1016-S0890-6955(02)00238-9	16	wear; composite; composites; powders; milling; particles; powder; wt; sliding; friction; hardness; matrix; mechanical; surface; properties	Electrode materials for electrical discharge machining (EDM) are usually graphite, copper and copper alloys because these materials have high melting temperature, and excellent electrical and thermal conductivity. The electrodes made by using powder metallurgy technology from special powders have been used to modify EDM surfaces in recent years, to improve wear and corrosion resistance. However, electrodes are normally fabricated at high temperatures and pressures, such that fabrication is expensive. This paper proposes a new method of blending the copper powders contained resin with chromium powders to form tool electrodes. Such electrodes are made at low pressure (20 MPa) and temperature (200 degreesC) in a hot mounting machine. The results showed that using such electrodes facilitated the formation of a modified surface layer on the work piece after EDM, with remarkable corrosion resistant properties. The optimal mixing ratio, appropriate pressure, and proper machining parameters (such as polarity, peak current, and pulse duration) were used to investigate the effect of the material removal rate (MRR), electrode wear rate (EWR), surface roughness, and thickness of the recast layer on the usability of these electrodes. According to the experimental results, a mixing ratio of Cu-0wt%Cr and a sinter pressure of 20 MPa obtained an excellent MRR. Moreover, this work also reveals that the composite electrodes obtained a higher MRR than Cu metal electrodes; the recast layer was thinner and fewer cracks were present on, the machined surface. Furthermore, the Cr elements in the composite electrode migrated to the work piece, resulting in good corrosion resistance of the machined surface after EDM.
10.1016-S0920-3796(02)00256-9	2	corrosion; surface; film; electrochemical; films; spectroscopy; layer; current; solution; potential; resistance; composition; x-ray; ions; showed	To investigate the erosion-corrosion behavior of the Cu-alloys, i.e. CuCrZr and CuA125-candidate materials for the manufacture of the diverter cooling channels for ITER, a test loop has been developed for testing erosion-corrosion behavior under high heat flux conditions. The heat loads on the test specimen surface amounts to 10 MW/m(2). Under adverse testing conditions in oxidizing water (5-10 ppm H(2)O(2)) at 100 degreesC, with a flow velocity of 10 m/s and intermittent heat loading, followed by cooling cycles under oxidizing conditions maintained, CuCrZr alloy has shown the formation of a thick surface oxide films (essentially cupric oxide, CuO). This surface layer seems loosely adhesive, and detachable by mechanical or thermal shocks, or by fluid flow velocity effects. Indicated with a rough morphology, surface attacks were somewhat observed in areas after the surface oxide layer spalled off. Present results suggest the necessity for, such as, strict hydrogen water chemistry (HWC), in order to limit the copper corrosion rate or at least the release of copper into the cooling water circuit. (C) 2002 Published by Elsevier Science B.V.
10.1016-S0920-3796(03)00184-4	5	materials; thermal; heat; properties; material; welding; sintering; fusion; strength; laser; heat sink; thermal conductivity; mechanical; sink; manufacturing	Due to its low atomic mass and high thermal conductivity beryllium is a candidate plasma facing material for the ITER primary first wall (PFW). HIP bonding and brazing have been used previously to bond beryllium tiles to the copper alloy heatsink. However, both methods employ temperature conditions that are incompatible with the otherwise attractive copper alloy, copper chrome zirconium (CuCrZr). This paper outlines the methodology used to develop a HIP bond compatible with CuCrZr and demonstrates its application towards the production of a PFW mock-up.
10.1016-S0920-5632(99)00606-4	-1		We carried out thermal conductivity measurements of Manganin wire having a composition of Cu 84%, Ni 4%, Mn 12% (sample 1) in the 0.1 divided by 1K temperature range, and of Manganin wire having a composition of Cu 86%, Ni 2%, Mn 12% (sample 2) in the 0.05 divided by 0.25K range. The measurements were performed in a low-power dilution refrigerator. For sample 1, the fit on the data gives a dependence on T: k = (0.79 +/- 0.01)T1.22+/-0.02 mW/cmK; for sample 2, the fit leads to k = (0.95 +/- 0.04)T1.19+/-0.02 mW/cmK. The difference in thermal conductivity in the overlapping temperature range depends on the different ratio of the Cu/Ni content of the samples. A similar sensitivity to a small difference in the composition has also been found for other Cu alloys.
10.1016-S0921-4526(01)00474-4	9	magnetic; magnetization; magnetoresistance; temperature; superparamagnetic; annealing; gmr; field; magnetic properties; ferromagnetic; granular; samples; magnetic field; melt-spun; particles	The microstructural characteristics of Cu based glass coated microwires are studied considering the different factors determined by their fabrication (composition and geometry), Two different sets of binary systems (CuxFe100-x and CuxCo100-x) and CU63Fe36P and Cu80Co19Ni samples have been studied. The parameter that describes the geometry is the ratio p between the diameter of the metallic nucleus and the external one corresponding to the layer of the Pyrex glass. It straightforwardly relates to the fabrication process of the samples owing to the strong internal stresses in the samples because of the different thermal expansion coefficients of the glass coating and the metallic nucleus. The structural study, carried out by means of wide angle X-ray scattering (WAXS) and a subsequent identification of the crystalline peaks, reveals that Feet and Co phases coexist with a Cu phase in each system. In the case of the samples containing P or Ni atoms, a third phase, Cu3P or Cu3.8Ni. respectively, appears. An evaluation of the relative content of each phase shows in each system a sort of a master curve with a non-linear p-dependence with a critical maximum at around rho = 0.25 for the Fe alpha and Co phases in the two systems. The calculation of the grain size shows that nanocrystals around 40 nm in size are formed in all the cases by Fe alpha, Co and Cu phases. Magnetic measurements are now in progress in order to complement these structural results. (C) 2001 Elsevier Science B.V. All rights
10.1016-S0921-4526(96)01233-1	4	transformation; martensite; martensitic; phase; shape; beta; memory; shape memory; temperature; temperatures; martensitic transformation; gamma; transformation temperatures; effect; thermal	The early stages of the decomposition reaction in Cu-0.9 at% Ti at 350 degrees C have been investigated by means of small- and wide-angle neutron scattering (SWANS). This technique is distinguished by an extremely high resolution superior even to that of high-resolution transmission electron microscopy (HRTEM) and field ion microscopy (FIM). The experimental results indicate a coarsening reaction of a considerably reduced rate to take place from the very beginning of the decomposition reaction.
10.1016-S0921-4526(98)00930-2	-1		(57)Fe Mossbauer absorption measurements are reported indicating that CuFeSe(2) and CuFeTe(2) have both a ground state of spin-density waves (SDW) nature. For the selenide it is a transverse commensurate SDW with T(N) = 71 K and for the telluride it is an incommensurate SDW with T(N) = 308 K.
10.1016-S0921-4526(98)00934-X	-1		In dilute alloys (CexLa1-x)Cu2.2Si2, Cu-NMR and NQR have been performed to investigate the non-Fermi-liquid behavior around x = 0.1. For x = 0.07, the 4f-contribution of(T1T)(-1) at 11 kOe is much larger than the calculated one in the case of dilute Kondo impurities, indicating that the antiferromagnetic spin fluctuations characterize the low-T spin dynamics.
10.1016-S0921-4526(99)00050-2	-1		Measurements of atomic and magnetic correlations in the plane perpendicular to the [1, 0, 0] axis for a Cu-5 at% Mn single crystal at low temperatures using polarised neutrons give clear evidence of weak atomic short-range correlations represented by broad humps close to (1, 1/2, 0)-type positions while magnetic correlations are evidenced as strong low Q-scattering and SDW-like peaks at (1, 1/2 +/- delta, 0)-type positions, as well as humps centred on (1, 1/2, 0) positions. The latter are superposed on a quasi-uniform 'background' of magnetic scattering representing a large fraction of the spin system frozen into quasi-random orientations at low temperatures. We suggest that the periodic nature of the lattice and the relatively strong magnitudes of the antiferromagnetic first-neighbour and ferromagnetic second- and third-neighbour interactions give rise to the SDW-like short-range order while the effect of the small amount of atomic short-range order is to enhance the latter at the expense of the uniform cross-section representing the randomly frozen spin system.
10.1016-S0921-4526(99)00092-7	-1		Single crystals of Heusler alloy Cu(2)MnAl are widely used to construct efficient focusing monochromators for polarized neutrons. Very large monocrystalline ingots of length 150 mm and diameter 60 mm have been grown with success at ILL during the last two years. A brief study of the quality of such ingots by neutron diffraction at wavelength lambda = 1.8 Angstrom is presented. We are able to produce large monograin slabs of dimensions 100 x 17 x 5 mm(3) whose (1 1 1) reflection is characterized by a width (FWHM) of 0.35 degrees, a peak reflectivity of about 30% (unmagnetised state) and a flipping ratio close to 40.
10.1016-S0921-5093(00)00633-X	-1		Tensile creep of nano-grained pure Cu with an average grain size of 30 mm prepared by electrodeposition technique has been investigated in the temperature range 20-50 degrees C (0.22-0.24 T-m). The steady state creep rate is found to be proportional to the effective stress sigma(e) = (sigma-sigma(0)), where sigma is the applied stress, and sigma(0) is the threshold stress. The activation energy for the creep is measured to be 0.72 eV, which is close to that for grain boundary diffusion in nano-grained Cu. The creep rates are found to be of the same order of magnitude as those calculated from the equation for Coble creep. The existence of threshold stress implies that the grain boundaries do not act as perfect sources and sinks of atoms (or vacancies). The results suggest that the creep can be attributed to the 'interface controlled diffusional creep'.
10.1016-S0921-5093(00)00712-7	-1		The objective of this work is to investigate the microstrain effect on grain growth and strain release processes in nanocrystalline (nc) samples. Two kinds of nc Cu samples were studied by using differential scanning calorimetry (DSC), X-ray diffraction (XRD) and transmission electron microscopy (TEM): an electro-deposited nc Cu sample with an average grain size of about 30 nm and one after cold-rolling in which the average grain size remain unchanged but the microstrain is substantially elevated. Measurement results indicated for the electro-deposited nc Cu, grain growth occurs at about 70 degrees C, which was prior to the major strain release process (onset at 150 degrees C). While for the as-rolled nc Cu, the grain growth onset temperature increases up to about 150 degrees C and that of the strain release process drops to about 115 degrees C. These results showed an evident correlation between the grain size stability and the microstrain in the nc materials.
10.1016-S0921-5093(00)00887-X	-1		Carbon fiber reinforced copper matrix composites have been produced by continuous three-step electrodeposition plus hot pressing technique. Iron or nickel element was added to copper matrix to improve interfacial bonding of the composite. The effects of fiber volume fraction and hot pressing parameters (temperature. pressure and time) on the tensile strength of the composite were investigated. Emphasis was placed on the Influence of alloying elements on the tensile strength of the composite. The composite was found to exhibit the highest strength at an optimum V-f, hot pressing parameter temperature, pressure, or time by keeping other parameters constant. This optimum value was related to the alloying element incorporated in the copper matrix. It is observed that incorporation of alloying elements does not change the general trends, but changes the mechanism governing the decreasing trends of the tensile strength of the composites as the hot pressing temperature exceeds the optimum value. Further. the alloying elements affect the highest strength values (sigma(max)). C/Cu(Ni) composite with the medium interfacial bonding strength exhibits the highest sigma(max). It is concluded from our experiments that a diffusion bonding is preferable since the fiber-matrix interaction can be easily controlled and the fiber degradation is limited during hot pressing process.
10.1016-S0921-5093(00)00925-4	4	transformation; martensite; martensitic; phase; shape; beta; memory; shape memory; temperature; temperatures; martensitic transformation; gamma; transformation temperatures; effect; thermal	Experiments have been performed in Cu-Zn-Al single crystals in order to further understand the evolution of material properties after continuous pseudoelastic cycling. In a fatigue experiment of this type, permanent and recoverable effects are observed for temperatures above 273 K. Experiments in the stress-strain-time space have been designed in order to separate both contributions. The occurrence of recoverable changes can be related to the ordering of the beta-phase and to the stabilization of the martensite, both depending in turn on the atomic diffusion phenomena in these alloys above 273 K. The kinetics of these processes show a considerable increase of the associated time constant after the pseudoelastic cycling procedure. The relation of these changes with the microstructural evolution of the material is analyzed and a discussion is offered on the role that each mechanism. either diffusive or due to microstructural changes, plays on fatigue. The relevance of defining a reference state in order to determine the consequences of pseudoelastic cycling is shown. A model which considers the stabilization of martensite and the beta recovery has been used to reproduce the stress deformation behavior after cycling. An enhancement of stabilization kinetics during fatigue has allowed us to obtain a closer fit with the experimental results.
10.1016-S0921-5093(00)01270-3	4	transformation; martensite; martensitic; phase; shape; beta; memory; shape memory; temperature; temperatures; martensitic transformation; gamma; transformation temperatures; effect; thermal	Investigation is carried out to understand the reasons behind the degradation of two way shape memory effect in Cu-Zn-Al alloy which exhibits a complete loss in its two way memory effect after a finite number of transformation cycles. It is observed that the two-way memory loss is attributable to a chemical effect viz. the precipitation of intermetallics at the martensite plate boundaries. Since repetitive thermal cycling is related to some kind of ageing effects, the present investigation also includes the study on the ageing behaviour of the alloys. The ageing effects are finally co-related with the observed two-way shape memory loss to describe the transformation fatigue found in the Cu-Zn-Al alloy.
10.1016-S0921-5093(00)01315-0	-1		This paper summarizes some of the literature on binary alloys, A-B. such as those based on Fe. Co, Ni or Cu and containing 0-30% of a higher valent, less noble metal, B. The oxidation essentially follows parabolic kinetics and the rate constants reach a maximum with additions of B around 5-10%. The oxygen pressure dependencies and temperature dependencies of the parabolic rate constants are stronger than for the unalloyed metal, A. The oxide morphology is considerably more complex than for unalloyed A and the oxide usually comprises an outer region consisting of AO and an inner two-phase region containing dispersed BO-particles and pores in a matrix of AO. Based on this review and a recent extensive study of the oxidation mechanism of Cu-Ni alloys, similarities in the oxidation mechanism of the different alloy systems are discussed.
10.1016-S0921-5093(00)01425-8	-1		This paper is intended to investigate the effect of additional solute elements on the glass-forming ability by studying the crystallization processes of Cu40Ti30Ni15Zr10Sn5 and Z(60)Ni(25)Al(15) amorphous alloys ill the supercooled liquid region, The crystallization of Cu40Ti30Ni15Zr10Sn5 amorphous ahoy takes place through the reactions of Am --> CuTi + Cu10Zr7 --> Cu10Zr7 + Cu3Ti + CuTi2 + Cu2Ti. Enrichment of Sn in the Cu10Zr7 phase was revealed by compositional analysis. On the other hand, the crystallization of Zr60Ni25Al15 amorphous alloy takes place through the reaction of Am --> Zr5Ni4Al + Zr6NiAl2. The common feature in the crystallization processes or; the two alloys is the necessity of significant redistribution of the solute elements (Sn or Al), which is believed to play an important role in the stability of the supercooled liquid against crystallization.
10.1016-S0921-5093(00)01477-5	7	irradiation; shear; grain; ta; deformation; size; radiation; voids; nanocrystalline; simulations; similar; void; temperature; irradiated; boundaries	Mechanical interactions between dendrites and their parent melt are normally considered insignificant. However, during rapid solidification the twin conditions of high How velocities and very fine dendrites required to produce mechanical damage may exist. A model for the skin stress resulting from flow around a family of realistically shaped dendrites is presented. We find that within a narrow undercooling range about a local minimum in the tip radius, mechanical deformation is likely. Experimental evidence is presented from a Cu-3 wt% Sn alloy undercooled by 73 K which appears to show evidence of a deformed dendritic structure.
10.1016-S0921-5093(00)01709-3	-1		By simultaneous high resolution recordings of stress and local strain along the specimen length, using a novel multizone laser scanning extensometer, the nucleation and propagation of Portevin-LeChatelier (PLC) deformation bands has been studied on Cu-15 at% Al polycrystals. The extensometer data provides an accurate classification of the types A, B and C of PLC bands as well as propagation rates, band strain and band width . These are compared with results of a new theoretical space-time analysis of propagating PLC bands which combines an explicit physical description of dynamic strain ageing kinetics with plastic deformation kinetics.
10.1016-S0921-5093(00)01885-2	-1		0.5 mass% Si has been added into the Cu-15Cr based alloy for the purpose of strengthening. The microstructure and properties of Cu-15Cr-O.5Si in situ composites have been investigated. Because of the effective hardening to Cr phase due to the addition of Si, both the thickness of Cr fibres and the interphase spacing are larger than the previous results in Cu- 15Cr in situ composites at the same drawing strain, therefore, the drawn structure is coarser due to the addition of Si. In addition to dissolving in Cu and Cr phases, Si also reacts with Cr to form Cr,Si (accounts for 4 vol.%), which is brittle and was broken during the following cold deformation. The hardness of both Cu and Cr phases in the as drawn wire increases with increasing drawing strain by work hardening. The tensile strength of as drawn Cu-15Cr--0.5Si in situ composites is superior to that of Cu-15Cr binary in situ composites only when the drawing strain is lower than 4.5.
10.1016-S0921-5093(00)01927-4	6	grain; deformation; strain; strength; dislocation; cu-; tensile; size; ecap; grain size; sfe; ductility; hardening; high; stress	[(1) over bar 12] Cu-7at./DAl single crystals as well as [(1) over bar 23], [(1) over bar 17] and [023] Cu-16at%Al single crystals were cyclically deformed under constant plastic strain control at room temperature. The cyclic hardening curve of [(1) over bar 12] Cu-7at%uAl single crystal can be divided into three stages, namely initial non-hardening stage, rapid hardening stage and saturation stage. The cyclic stress-strain (CSS) curve exhibited a plateau region in the range of gamma (pl). from 1.1 x 10(-3) to 4.5 x 10(-3). The saturation stress of the plateau is about 27 MPa. The occurrence of strain burst depends on the applied plastic strain amplitude gamma (pl). No strain burst was detected when gamma (pl), was below 4.4 x 10(-4) or above 1.1 x 10(-3). The cyclic deformation and strain burst behavior of [(1) over bar 23], [(1) over bar 17] and [023] Cu-16at%Al single crystals are different from that of [(1) over bar 12] Cu-7at%Al single crystal. The cyclic deformation of all three differently oriented Cu-16%Al single crystals is unstable with the frequent occurrence of irregular strain bursts. The specimens cyclically hardened at a very low rate and saturation was not attained at high strain amplitudes. The experimental results indicate that the crystallographic orientation has almost no effect on the cyclic deformation and strain burst behavior of Cu-16at%Al single crystals. The evolution of slip bands during cyclic deformation in both Cu-7at%Al and Cu-16at%Al single crystals is similar to the development of Luders band. The percolation of slip bands along the gauge length is generally accompanied by strain bursts. The above experimental results were explained in terms of the variation of slip mode with Al content in the alloys and the corresponding strain localization during cycling.
10.1016-S0921-5093(00)02023-2	4	transformation; martensite; martensitic; phase; shape; beta; memory; shape memory; temperature; temperatures; martensitic transformation; gamma; transformation temperatures; effect; thermal	Cu-Zn-Al single crystals have been pseudoelastically cycled through the bcc-18R martensitic transformation. The test temperatures varied from low temperatures (liquid nitrogen) to above room temperature. The microstructure evolution during cycling has been analyzed by optical and transmission electron microscopy. A description of defects formed after cycling both in the bulk and on the surface is presented. A transition in the type of formed defects is found corresponding to an increase in the test temperature. Dislocation tangles parallel to the basal plane of the martensite, with trapped martensite inside, give way to dislocation arrays parallel to the habit plane of the transformation, as the test temperature increases. A correlation between this transition behavior and the mechanical evolution was found and the mechanisms of generation of bulk and surface defects are discussed. A correlation between dislocation arrays parallel to the habit plane and intrusion-extrusion defects on the surface is also presented. Both type of defects appear at temperatures higher than 173 K. The effect of point defects introduced during cycling and their change in mobility with test temperature are considered.
10.1016-S0921-5093(01)01306-5	-1		Atom probe field-ion microscopy (APFIM) has been established as a sensitive analytical method for the investigation of the local chemical composition on nanometer scales. The adaptation and operation of a position sensitive detection system to the APFIM, named tomographic atom probe (TAP), improve substantially the quantitative character of analysis with this method. The TAP provides spatially resolved information on the position in real space and chemical nature of each collected atom of the sampled volume. The extended set of data collected by the TA-P can be treated with special visualizing tools. Three-dimensional images are created, which include all the information on microstructure and chemical composition of the sampled volume with atomic resolution. This paper demonstrates the capability of the TA-P to determine the decomposition parameters. Results on the phase decomposition in selected supersaturated alloys (Cu-Co, Al-Li and Ni-Be) are reviewed to gain an insight into the benefits and difficulties of this novel analytical method.
10.1016-S0921-5093(01)01313-2	-1		Wire samples of different diameters of homogenized commercial Cu-Be alloys are deformed, displacement controlled, in a liquid helium bath at strain rates between 5 x 10(-3) and 5 x 10(-1) s(-1). For a considerable fraction of samples where the strain rates are well above the transition between regular serrations and extended regular patterns, strong irregularities occur. For load versus time diagrams where regular patterns occur, indicating the propagation of deformation bands from one grip to the other, band propagation velocities are determined. The velocities decrease with increasing stress level and increasing sample thickness, but increase with increasing strain rate in qualitative agreement with theoretical findings. The results confirm the occurrence of propagating deformation bands and qualitatively support the theory.
10.1016-S0921-5093(01)01683-5	4	transformation; martensite; martensitic; phase; shape; beta; memory; shape memory; temperature; temperatures; martensitic transformation; gamma; transformation temperatures; effect; thermal	The precipitation of the gamma phase in quenched beta Cu-Zn-Al alloys at an electron concentration (e/a) of 1.53 was studied in detail by optical, scanning and transmission electron microscopy. Two precipitation processes were found: (i) a dendritic precipitation in cuboidal regions of 10-40 mum was found at low quenching velocities, below about 500 K s(-1), but was suppressed by increasing the quenching rate to 1150 K s(-1); (ii) small spheroidal precipitates with gamma-brass structure, typically 10 nm in size, were observed even after quenching at the highest velocities. They formed on first- and second-neighbour antiphase boundaries. The latter process was found to occur more readily than in Cu-Zn-Al alloys at e/a = 1.48. The hysteresis of the spontaneous martensitic transformation was not appreciably affected by the presence of the latter precipitates.
10.1016-S0921-5093(01)01847-0	-1		The kinetics of diffusion induced recrystallization (DIR) in the Cu(Ni) system was experimentally Studied at 873 K. Ni/(Cu-Ni)/Ni diffusion couples were prepared by a diffusion bonding technique using a pure Ni specimen and binary Cu-Ni alloys with mol fractions of Ni of y(0) = 0, 0.114 and 0.231, and then annealed at 873 K for various times between 1 and 72 h (3.6 x 10(3) and 2.59 x 10(5) s). After annealing, a fine grain region (DIR region) alloyed with Ni was observed to form at the interface owing to DIR and to grow mainly towards the Cu phase. The thickness l of the DIR region monotonically increases with increasing annealing time t according to the relationship l = k(t/t(0))(n), where t(0) is unit time, 1 s. The exponent n takes a constant value of 0.45 independent of the composition y(0). On the other hand, as the composition y(0) increases from 0 to 0.231. the proportionality coefficient k decreases from 5.7 x 10(-8) to 4.5 x 10(-8) m. The experimental results were theoretically analyzed using a kinetic model proposed by the present authors. The growth behavior of the DIR region was explained well by the analysis. This means that the chemical driving force due to the compositional difference between the Cu phase and the DIR region is the most important driving force for DIR in the Cu(Ni) system under the present experimental conditions.
10.1016-S0921-5093(01)01875-5	-1		Cu-20at% Co was mechanically alloyed from pure elements by ball milling for 28 h . The powder was compacted into pellets at room temperature by applying a pressure of 0.5 GPa. Microstructural investigations were carried out by three-dimensional atom probing (3DAP) after annealing at 400 degreesC for 2 h in Ar atmosphere. The annealed Cu 20at% Co exhibits a heterogeneous microstructure. Cu-rich and Co-rich particles with 8.7 at% Co and 1.3 at% Cu, respectively, and highly supersaturated regions with average Co concentrations between 25 and 35 at% were detected. A new, sensitive statistical analysis of the 3DAP data obtained from a supersaturated region revealed concentration fluctuations of 24 at% Co with an average wave length of about 2 nm indicating spinodal decomposition.
10.1016-S0921-5093(01)01884-6	-1		A new approach to preparing tips for atom probe field ion microscopy from powder materials is described, It is especially useful for particle sizes exceeding > 0.050 mm. Particles resulting from mechanical alloying of Cu and Ag, and from cryomilling of conventional Ni powders have been prepared this way for field ion imaging and atom probe composition analysis. In both cases, useful information complementing results from transmission electron microscopy and X-ray diffraction was obtained.
10.1016-S0921-5093(01)01914-1	2	corrosion; surface; film; electrochemical; films; spectroscopy; layer; current; solution; potential; resistance; composition; x-ray; ions; showed	Electrodeposition in the potentiostatic mode has been used to produce Cu-Co metastable alloys. The influence of different plating parameters, such as bath composition, working electrode voltage (vs. reference) and intensity of agitation, on the composition and properties of the deposit has been investigated. A broad range of compositions (2-26 at% Co) are obtainable. In particular, the Co content in the samples is determined mainly by the Co concentration in the bath and the electrode voltage applied during the deposition. The lack of agitation produces a deposition with a higher Co content. Experimentally obtained magnetic loops have been fitted successfully taking into account a superparamagnetic cluster size distribution. From these fits we conclude that the as deposited samples consist of superparamagnetic clusters and diluted Co atoms which do not contribute to magnetisation. These results demonstrate that electrodeposition is a promising and inexpensive preparation method for obtaining Cu-Co heterogeneous alloys with controllable and adequate properties for technological applications.
10.1016-S0921-5093(01)01945-1	6	grain; deformation; strain; strength; dislocation; cu-; tensile; size; ecap; grain size; sfe; ductility; hardening; high; stress	The high temperature tensile properties of a Cu-1.5 wt% Ti alloy have been investigated in the temperature range of 100-550 degreesC. Substantial increase in yield and tensile strengths of solution treated alloy is observed with increasing temperature, with a peak at 450 degreesC and decrease in strength beyond this temperature. In situ age hardening during testing at elevated temperatures resulting in the precipitation of ordered, metastable and coherent Cu4Ti (beta(1)) phase is attributed to the increase in strength up to 450 degreesC and coarsening of beta(1) precipitate particles decreases the strength at temperatures greater than 450 degreesC. In the peak-aged condition, however, the yield and tensile strengths are nearly constant up to 350 degreesC and decrease thereafter, up to 550 degreesC. The decrease in strength beyond 350 degreesC in the peak aged Cu-1.5Ti alloy is attributed to the coarsening of precipitate particles and thermally activated cross-slip occurring at high temperatures, which makes the movement of the dislocations easy. The high temperature tensile properties of Cu-1.5Ti alloy are comparable at 300 degreesC and even better at 425 degreesC than those of Cu-1.5Ti-2.5Sn, Cu-1.5Ti-2.5Sn-0.5Cr and Cu-0.65Be-2.7Co alloys. Ductile mode of fracture is observed even at elevated temperatures.
10.1016-S0921-5093(02)00089-8	-1		The influence of the Fe solubility difference on the saturation magnetization of the Cu-Fe alloy was investigated. Magnetic measurements of an annealed Cu-0.85mass% Fe and Cu-1.60mass% Fe alloys with fully transformed Fe particles have been conducted for this purpose. The saturation magnetization of the aged and deformed specimens was raised further by annealing at 973 K after deformation. It appears that the increase in saturation magnetization results from absorption of dissolved Fe atoms by the alpha-Fe particles during the annealing. The solubility of Fe in Cu at 973 K in the presence of gamma-Fe and alpha-Fe was determined to be 0.46 and 0.38 mass%, respectively.
10.1016-S0921-5093(02)00124-7	4	transformation; martensite; martensitic; phase; shape; beta; memory; shape memory; temperature; temperatures; martensitic transformation; gamma; transformation temperatures; effect; thermal	Duplex type aluminum bronzes usually exhibit a structure consisting of alpha and the interconnecting eutectoid matrix of alpha and gamma particles. These gamma particles are highly anodic to the a particles. Usually the beta phase is retained because it is less anodic to alpha particles than the gamma phase. In our previous study, observation of the development of dealuminification corrosion of Cu-9Al-2Mn alloy in an early stage was first carried out by in situ scanning tunneling microscope (STM). It has been indicated that the existence of the beta phase has a negative effect on dealuminification corrosion of aluminum bronzes, which occurs preferentially on the beta phase. In order to determine the influence of beta phase transformation in Cu-Al-Mn alloys on their dealuminification micro-mechanism, the change in the microstructure before and after dealuminification corrosion of Cu-9Al-2Mn alloy was investigated in the present work. Results indicate that dealuminification corrosion of Cu-9Al-2Mn alloy is associated with martensite transformation of metastable beta(1) phase and occurs within the beta(1)' martensite plates, in which there is a large amount of stacking faults. Micro-pits and fine corrosion products were also observed by TEM. The reason why beta(1)' martensite plates suffered a preferential dealuminification corrosion is martensite transformation of beta-Cu3Al phase and the higher density of stacking faults in beta(1)' martensite plates.
10.1016-S0921-5093(02)00214-9	-1		The acoustic emission (AE) has been investigated systematically in tensile strained model Cu-Ge alloys with germanium concentration varied from 0.1 to 9.0 at%. The role of various micro-structural factors in AE is discussed and the effects of solid solution hardening and stacking fault energy (SFE) on the AE power spectra are clarified. It is shown that even a small (0.1 at%) addition of Ge changes AE significantly, whereas the dislocation AE mechanisms are similar in pure copper and its dilute alloys. It is argued that the solution hardening is a main factor governing the AE behaviour in dilute Cu-Ge solutions, resulting in the increase of lattice friction, decrease of dislocation velocity and, consequently, in reduction of the AE energy. The AE technique shows that twinning occurs from the very early stage of plastic deformation together with dislocation slip in copper alloys with germanium content as high as 5.7 at% and the SFE is of 20 mJ m(-2) and lower. Both types of AE sources-dislocation glide and twinning- have distinct features in the AE power spectra and waveforms and are discriminated with a help of data categorization technique and cluster analysis of AE.
10.1016-S0921-5093(02)00306-4	6	grain; deformation; strain; strength; dislocation; cu-; tensile; size; ecap; grain size; sfe; ductility; hardening; high; stress	A copper alloy containing 0.61 wt% Cr and 0.07 wt% P was solution annealed and cold deformed to true strains ranging from 0.1 to 0.9. After being aged at 510 degreesC for different times, the deformed alloy was characterized using the measurement of Vickers hardness, optical microscopy and transmission electron microscopy. During the isothermal aging, the hardness of the deformed alloy showed three distinct stages as a function of aging time; this hardness behavior was associated with the interactions between precipitation, recovery and recrystallization. The amount of prior deformation and aging time influenced the interactions of the three processes. On aging, the lightly deformed alloy exhibited a retarded recrystallization process and therefore an efficient hardening response. The heavily deformed alloy ( > 0.7 strain) showed an accelerated process of recrystallization so that a long time aging (e.g. 60 min) resulted in an inefficient precipitation hardening due to the increased softening with the progress of recrystallization. The results of this study suggest that the precipitation process should occur before the onset of recrystallization during the aging of a deformed supersaturated alloy in order to result in an efficient hardening. This condition can be achieved by controlling the amount of prior deformation, aging temperature and time.
10.1016-S0921-5093(02)00521-X	6	grain; deformation; strain; strength; dislocation; cu-; tensile; size; ecap; grain size; sfe; ductility; hardening; high; stress	By means of equal channel angular extrusion (ECAE), pure Cu single crystal samples were processed down to the submicron scale. In some parts of the samples, recrystallization occurs at room temperature. The recrystallization mechanism was analyzed by SEM-EBSP and SEM-ECC techniques. The grain boundary character distribution (GBCD) and orientation distribution function (ODF) of the regions undergoing recrystallization were computed. The results show that the nuclei can be formed at the intersections of two different shear bands, and the microstructures and the grain boundary characters in these locations contribute to growth of recrystallized nuclei. The recrystallized grains had grown according to the Feltham's mechanism.
10.1016-S0921-5093(02)00589-0	-1		Model experiments were conducted to evaluate the shearing characteristics associated with processing through equal-channel angular pressing (ECAP). A Cu matrix was used with embedded inserts of either pure Al or a Cu-30% Zn alloy. When using aluminum, the experiments show good agreement with the theoretical predictions except that the embedded element, which has less strength than the Cu matrix, experiences greater shearing than anticipated. Conversely, the Cu-30% Zn alloy is stronger than the Cu matrix and, since the insert is not fully constrained, the shearing is then less than anticipated. Using an embedded sample of pure Al cut to the dimensions of the parallelepiped anticipated for a single pass of ECAP, it is shown that processing by route C, where the specimen is rotated by 180degrees between passes, effectively restores the cubic element in the second pass. The experiments confirm I the pressing speed has no significant effect on the shearing characteristics, at least within the range from 0.2 to 18 mm s(-1).
10.1016-S0921-5093(02)00590-7	-1		Modeling the electrical conductivity of composite materials is a complex matter, particularly if microstructural features lead to a size effect in electronic conduction or create an anisotropy. The method described in this article accounts for these circumstances by incorporation of appropriate phenomenological models. It provides a means to analyze and estimate the resistive behavior of two-phase or multi-phase micro-composites and nano-composites. A comparison with experimental data is carried out for two high-strength conductors, Ag-Cu and Cu-Nb, both of which have undergone extensive quantitative microstructure analysis to provide the required input for the model.
10.1016-S0921-5093(02)00673-1	-1		The early stages of precipitation of the Fe-rich phase in supersaturated Cu-Fe alloy were studied with the field ion microscope and the tomographic atom probe. The specimens of nominal composition Cu-0.7at% Fe were homogenized at 1173 K and immediately aged in a salt bath for different times at 803 K to follow the decomposition path at this reaction temperature. In this work, preliminary results on the temporal evolution of the decomposition are presented. In particular, the particle radii and particle number density were determined as a function of the ageing time. At the initial stages of the decomposition concentration, fluctuations were observed, which could be quantitatively characterized. The decomposition sequence is discussed in terms of the nucleation and growth theory.
10.1016-S0921-5093(02)00688-3	-1		The tensile behaviour of a co-deformed Cu-10vol.% Cr composite has been studied. The composite was produced from cast Cu-Cr by hot forging and then cold swaging to a reduction of 95.6% in order to attain a fibrous reinforcing microstructure. Tensile testing in situ on a neutron diffractometer has allowed the evolution of axial and transverse elastic strains in each phase to be monitored as a function of applied stress. The results show that contrary to expectation, inelastic load transfer occurs from the Cr to the Cu matrix. The measured elastic strains are compared with an Eshelby type model and the retained misfit between the phases calculated. Since damage of the fibres, even near the fracture surface was limited, it is inferred that load transfer to the matrix occurs by the greater relative plastic straining of the reinforcement.
10.1016-S0921-5093(02)00724-4	6	grain; deformation; strain; strength; dislocation; cu-; tensile; size; ecap; grain size; sfe; ductility; hardening; high; stress	A powder mixture consisting of Cu-29.7at% Zn alloy and graphite was mechanically alloyed in a planetary ball mill. The supersaturated solid solubility of carbon in the Cu-29.7at% Zn alloy was determined to be 38.5at% C (alloy composition: Cu-18.3at% Zn-38.5at% C) by the change in lattice parameter of the alloy. Supersaturated Cu-24.2at% Zn-18.5at% C alloy powder consolidated by a static compression stress of 1.4 GPa was found to have a relative density of 89.7%, a Vickers hardness of 147.2, and a compressive strength of 1.4 GPa which is equal to the statically consolidated compression stress. Moreover, the supersaturated solid-soluble carbon did not precipitate. When dynamically consolidated by a 93 g projectile at a speed of 38.1 m s(-1) (estimated impact compression stress of 2.3 GPa) after static precompression of 0.4 GPa, the alloy powder was found to have a relative density of 93%, a Vickers hardness of 177, and a compressive strength of 2.3 GPa which is equal to the impact compression stress. Supersaturated solid solubility of 18.5at% C decreased to 15at% C after impact consolidation. The mechanically alloyed powders can maintain supersaturated solid solubility when consolidated by impact pressure, and especially when consolidated by static pressure.
10.1016-S0921-5093(02)00734-7	2	corrosion; surface; film; electrochemical; films; spectroscopy; layer; current; solution; potential; resistance; composition; x-ray; ions; showed	The present work deals with the inhibiting effects of imidazole on the pure copper (Cu) corrosion in 1 M HNO3 solution analysing potentiodynamic polarisation curves, potentiostatic anodic current transient, AC impedance spectra and X-ray photoelectron spectra (XPS). By adding imidazole to HNO3 Solution, the polarisation curves showed decrease in the corrosion current and the cathodic current, suggesting that imidazole acts as an effective cathodic inhibitor to Cu corrosion. From the measured anodic current transients, it is inferred that the protective Cu-imidazole complex film is simultaneously formed with the Cu oxide in the presence of imidazole during the early stage of the anodic polarisation. Analysis of the AC impedance spectra revealed that the values of the charge transfer resistance R-ct obtained in imidazole-containing HNO3 solution were greater than that value in imidazole-free one and at the same time steadily increased with immersion time to the constant value. Contrarily, the capacitance value was abruptly lowered from the double layer capacitance C-dI to the complex film capacitance C-cf in the progress of immersion time. Furthermore, the Warburg coefficient a value for the ion diffusion through the complex film was observed to increase with immersion time. This means that the Cu(N-OH) complex film becomes thicker during immersion in the HNO3 solution with imidazole through the inward growth of the N-rich outer layer to the O-rich inner layer, as well validated by XPS. Based upon the experimental results, it is suggested that the Cu corrosion in 1 M HNO3 solution is efficiently inhibited with the addition of imidazole by retarding both the charge transfer on cathodic sites of the Cu surface in the early stage of immersion time and the subsequent ion diffusion through the steadily growing complex film. (C) 2002 Published by Elsevier Science B.V.
10.1016-S0921-5093(02)00786-4	4	transformation; martensite; martensitic; phase; shape; beta; memory; shape memory; temperature; temperatures; martensitic transformation; gamma; transformation temperatures; effect; thermal	The length change associated with the compression induced beta-18R transformation for Cu-Zn-Al single crystals (SC) is measured. The results of deformation based on the invariant plane strain model and the phenomenological theory are in very good agreement with the experimental values. The invariant plane strain components, the dilatational and the shear component, are evaluated. The resulting relative volume change going from martensite to beta is xi = -0.0016 +/- 0.0002, and the shear component is s 0.1985 +/- 0.0004.
10.1016-S0921-5093(02)00789-X	4	transformation; martensite; martensitic; phase; shape; beta; memory; shape memory; temperature; temperatures; martensitic transformation; gamma; transformation temperatures; effect; thermal	Pseudoelastic beta(1)<---->beta(1)' and beta(1)<---->beta(1)' + gamma(1)' cycling in Cu-14.3Al-4.1Ni (wt%) single crystals were performed. For the beta(1)<---->beta(1)' cycling no evolution of the stress-strain curves was observed up to N = 2700 in a specimen oriented close to the [100] direction. For the beta(1)<---->beta(1)' + gamma(1)' cycling, made in a sample with orientation near [110], the martensitic transformation changes with the number of cycles, showing a clear inhibition of the gamma(1)' martensite as the cycling progresses. The disappearance of the 2H martensite is discussed in terms of the introduction of defects during cycling.
10.1016-S0921-5093(03)00003-0	4	transformation; martensite; martensitic; phase; shape; beta; memory; shape memory; temperature; temperatures; martensitic transformation; gamma; transformation temperatures; effect; thermal	Temperature-induced transformations under constant tensile loads (thermomechanical cycling) have been performed on a set of Cu-Al-Ni-based shape-memory ribbons prepared by melt spinning. The rapidly solidified ribbons being already characterized in what concerns martensite and parent phase ageing and their effects on the thermal (stress free) martensitic transformation, the purpose of this study was to complete the characterization of the ribbons, particularly in their shape-memory effect. The results presented for a Cu-13.0 Al-4.0 Ni-0.3 Ti-0.05 B (wt%) ribbon show larger recoverable strains in the strain-temperature cycles (thus larger shape-memory effect) for ribbons aged at 200 degreesC than for the as-spun samples. The dependence of the transformation temperatures T on the applied load, quantified through the slope dT/dsigma, increases for aged alloys. Both results can be related to the recovery of internal stresses produced by the rapid solidification and some recovery of short-range disorder, both mechanisms favouring higher values of the effective transformation strain. This behaviour is in agreement with the evolution of transformation temperatures in stress free transformation and related microstructural changes produced by ageing the ribbons in parent phase.
10.1016-S0921-5093(03)00041-8	-1		The phase transition of the Cu-14.1 wt% Al-9.0 wt% Ni alloy has been examined by transmission electron microscopy and energy-dispersive X-ray analysis. In the as-quenched condition, the microstructure of the alloy was Do(3) phase that contained extremely fine L-J precipitates. During the early stage of isothermal aging at 500 degreesC, a high density of the extremely fine B2 particles was observed within the extremely thin lamellar gamma(1)' martensite, which was formed by a D0(3) --> gamma(1)' martensitic transformation during quenching. With increasing aging time at 500 degreesC, the isothermal phase transition sequence was found to be D0(3) --> D0(3) --> B2 --> D0(3) + B2 + alpha --> B2 + alpha + gamma(2). This transition significantly differs from that observed by other researchers. Besides, both Kurdjumov-Sachs (K-S) and Nishiyama-Wassermann (N-W) orientation relationships between the B2 particle and the alpha phase could be detected in the aged alloy.
10.1016-S0921-5093(03)00081-9	-1		Creep in copper dispersion strengthened with fine alumina particles (oxide dispersion strengthened (ODS) Cu) and reinforced with alumina short fibres-a DRS Cu composite-is investigated in two temperature intervals, namely 673-773 K, lower temperature interval (LTI) and 923-1023 K, higher temperature interval (HTI). It is shown that in both intervals creep is associated with true threshold stresses decreasing with increasing temperature more strongly than the shear modulus of copper. The true threshold stress in the composite is higher than that in the composite matrix (i.e. ODS copper) by a factor Lambda, by which the flow stress in the matrix is reduced due to load transfer. The minimum creep strain rate is found to be dislocation core diffusion controlled in LTI and lattice diffusion controlled in HTI. High values of the apparent activation energies are fully explained in terms of the temperature dependence of the true threshold stress in LTI as well as in HTI. Also the values of the apparent stress exponents are explained in terms of the true threshold stresses. The true threshold stress is identified with the athermal detachment stress sigma(d) = sigma(OB) root1-k(R)(2), and its nonproportionality to the Orowan stress sigma(OB) is explained by the relaxation factor k(R) increasing with temperature.
10.1016-s0921-5093(03)00308-3	-1		A modified first order kinetic law which describes the roles of bound and unbound vacancies is proposed in order to predict defect decay and short-range-order (SRO) kinetics of quenched binary alloys during linear heating experiments. The model has been applied to differential scanning calorimetry (DSC) thermograms of Cu-10at% Al quenched from different temperatures. Transient effects at the end of de-freezing when heating after quenched were examined. Activation energy for migration of solute-vacancy complexes was also assessed from the kinetics of SRO using DSC traces. A value of 85.6 U mol(-1) was obtained. The relative contribution of bound and unbound vacancies to the ordering process as influenced by quenching temperature was determined.
10.1016-S0921-5093(03)00325-3	4	transformation; martensite; martensitic; phase; shape; beta; memory; shape memory; temperature; temperatures; martensitic transformation; gamma; transformation temperatures; effect; thermal	The stabilisation of the 18R stress induced martensite in Cu-Zn-Al single crystals has been measured as a function of the ageing time and the previous thermal treatment in the high temperature beta phase. It is found that the initial and final stages of the stabilisation present a different behavior, and only the latter is related to the quenched-in vacancy concentration. It is confirmed that the martensite does not reach its thermodynamical equilibrium state, although the vacancies remain mobile. It is suggested that the evolution of the martensite can be rationalised by the combined action of mobile vacancies and precursors of the gamma equilibrium phase.
10.1016-s0921-5093(03)00368-x	-1		A modified first-order kinetic law which takes into account defect decay during an ordering process was employed to predict the short-range-order kinetics of a quenched alphaCu-10at% Al alloy, in conjunction with experiments performed by differential isothermal calorimetry (DIC). The effective activation energy of point defect migration and its temperature dependence strongly suggests the contribution of bound vacancies to the ordering process. An estimate of 87.6 kJ mol(-1) was made for the activation energy of solute-vacancy migration by applying an effective rate constant, a value which is quite reasonable, since it lies between the activation energy of migration of unbound vacancies and the activation energy for complex dissolution. The isothermal curves were utilized to determine the ordering energy: w = -3.66 kJ mol(-1).
10.1016-S0921-5093(03)00515-X	4	transformation; martensite; martensitic; phase; shape; beta; memory; shape memory; temperature; temperatures; martensitic transformation; gamma; transformation temperatures; effect; thermal	Instead of cycling stress or temperature repeatedly through the transformation temperature, it is possible to obtain the two-way shape memory effect (TWME) by pre-ageing the martensite. Results are reported on the influence of the grain size on the magnitude of the TWME and on the work that can be done against an opposing force. The properties of aged Cu-Zn-Al crystals with three different grain sizes are compared, namely single crystals, fine-grained polycrystals obtained by adding grain refiners, and coarse-grained polycrystals without grain refiners as an intermediate case. The usefulness for technological applications of the TWME induced by ageing is discussed.
10.1016-S0921-5093(03)00636-1	-1		The structure of Cu-25 wt% Sn in the liquid state with different temperatures has been determined by using X-ray diffraction studies. It has been found that there exists not only short-range order (SRO) but also medium-range order (MRO) in the melt of Cu-25 wt% Sn alloy. Distinct pre-peaks have been found in front of the main peak of the total structure factor. Pre-peak positions shift to the large-Q side with increasing temperatures. Structural unit sizes corresponding to the pre-peak are not unchanged and thus, MRO in the Cu-25 wt% Sn is unstable. The nearest neighbor distance, the coordination number and the atomic density present a identical variation trend in the range of 1000-1200degreesC, which shows that structural variation of SRO occurs at 1000degreesC.
10.1016-S0921-5093(96)10582-7	-1		A series of solidification experiments with different cooling rate for copper alloys were performed. The cooling rates and solidification under-cooling temperatures were evaluated from the cooling curves. The heat transfer coefficient and heat of fusion were calculated. It was observed that the heats of fusion are much lower than tabulated values, it was assumed that this was a result of the number of vacancies formed during the solidification process. Consequently, the effects of vacancies formed during solidification for different cooling rates were analysed. It was found that the classical solidification model should be modified in order to explain the results properly. Therefore the present solidification model, considering the effect of formation of vacancies on the solidification behavior and the thermodynamic properties, is proposed. (C) 1997 Elsevier Science S.A.
10.1016-S0921-5093(96)10587-6	-1		The techniques of electromagnetic levitation, drop-tube processing and atomization are used to study containerless solidification of the Cu-Ni and Fe-Ni systems. Microstructure-selection maps are developed for the case of droplet solidification where droplet diameter and undercooling are the process parameters. The microstructure varies systematically with undercooling and composition, such that grain-refined microstructures are produced at both low and high undercoolings and dendritic microstructures are produced at intermediate undercoolings. The results are analyzed within a recently developed model for grain refinement which is based on the fragmentation of primary dendrites. The role of cooling rate in determining whether the microstructure transforms in the solid state or is retained as a primary structure is explored. (C) 1997 Elsevier Science S.A.
10.1016-S0921-5093(97)00257-8	-1		A study of post-deformation annealing was made on Cu-15at%Al cold-rolled to about 60% reduction in thickness. Starting from results as measured by electrical resistivity, changes of simultaneous defect recovery and short-range ordering (SRO) were compared with microhardness measurements. It is shown that changes of SRO can be carefully separated from simultaneously occurring processes of defect recovery. Further, SRO-kinetics in the deformed state is compared with that of completely recrystallized state. (C) 1997 Elsevier Science S.A.
10.1016-S0921-5093(97)00269-4	16	wear; composite; composites; powders; milling; particles; powder; wt; sliding; friction; hardness; matrix; mechanical; surface; properties	Nanoscaled Al2O3-powders (n-Al2O3) with a median particle diameter of 14 nm are distributed in microscaled copper powders by ball milling in a planetary mill followed by uniaxially hot pressing. The microstructures of the samples are analysed by SEM and EDX investigations and the hardness of the specimens is determined before and after heat treatments of the composites. The results on the produced Cu/n-Al2O3 composites show that the nanoparticles are largely homogeneously distributed in the matrix grains, that the matrix grains are stabilised against growth even after heat treatments close to the melting temperature of Cu, and that the hardness of the sample is largely maintained after heat treatment. The results show that mechanical alloying of metal micropowders with oxide ceramic nanopowders can produce dispersion-strengthened materials. The mechanical alloying with n-powders can be easily applied to systems which cannot be dispersion-strengthened with n-oxide ceramics by other methods, e.g. internal oxidation, The last is shown by dispersion-strengthening of magnesium with n-Al2O3. (C) 1997 Elsevier Science S.A.
10.1016-S0921-5093(97)00276-1	-1		Homogenized Cu-2 wt% Be-0.3 wt% Co wires of different diameters, D, show in a tensile test in a He bath at a strain rate of 5 x 10(-3) s(-1) regular stress serrations. By increasing the strain rate above a characteristic value (varying nearly as D-0.5) the regular serrations change gradually to extended patterns. We show by considering a local thermal equilibrium state at the site of a stress drop that this dependence of characteristic strain on sample diameter is in accordance with the assumption of a critical local sample temperature (independent of the diameter) occuring during the stress drop. The variation of stress causing the patterns at high strain rates suggests the existence of propagating slip bands there. For strain rate changes from 1.4 x 10(-6) to 1.4 x 10(-5) s(-1) in the continuous part of the deformation curve we find a small but positive stress rise which does not change appreciably with deformation thus ruling out a gradual change from positive to negative strain rate sensitivity as a cause for the onset of the serrations. (C) 1997 Elsevier Science S.A.
10.1016-S0921-5093(97)00298-0	-1		This work brings experimental observations on 295 and 77.4 K necking and twinning phenomena occurring at the end of overshoot in Cu-Al single crystals tested in tension. Critical concentrations of aluminium for a transition of overshoot necking-->overshoot twinning to occur were found. It was also found that the disappearance of load drops which usually accompany mechanical twinning of more dilute alloys is controlled by critical solute concentration. A simple explanation of both types of transition which is based on gamma/b criterion has been suggested. Strengthening of F.C.C. materials due to mechanical twinning is also discussed. (C) 1997 Elsevier Science S.A.
10.1016-S0921-5093(97)00378-X	4	transformation; martensite; martensitic; phase; shape; beta; memory; shape memory; temperature; temperatures; martensitic transformation; gamma; transformation temperatures; effect; thermal	Long-range ordered (18R structure) Cu-Zn-Al single crystals with the stacking sequence ABCBCACAB of close packed planes have been plastically deformed in compression. The dislocations move on the basal plane and have the shortest possible translation Burgers vector. The critical resolved shear stress increases with temperature above room temperature and the strain rate sensitivity decreases, reaching negative values at elevated temperatures. The results cannot be explained by an increased friction stress of the moving dislocations due to diffusion induced reordering of the antiphase boundary between the partials. It is instead suggested that diffusion modifies the dislocation configuration, essentially after it gets immobilized at obstacles. (C) 1997 Elsevier Science S.A.
10.1016-S0921-5093(97)80061-5	-1		The kinetics of the polymorphic transformation of a Ti38.5Cu32Co14Al10Zr5.5 glassy alloy to an ordered bcc phase was determined by means of combined DSC, XRD and TEM experiments. Samples annealed isothermally under Ar at 723 K for 5, 10, 15, 20 min contain crystals up to 20 nm in size. After the quick formation of nanocrystals, growth is almost blocked. Samples contained in Al pans sealed in a glove box, gave DSC signals significantly displaced at longer times showing an effect of the annealing atmosphere on the crystallization kinetics. This was confirmed by annealing other samples in vacuum. The size of the crystals after these longer annealings is still in the nanometer range. The size distribution, determined on TEM micrographs is compatible with nucleation on homogeneously distributed impurities. (C) 1997 Elsevier Science S.A.
10.1016-S0921-5093(99)00295-6	4	transformation; martensite; martensitic; phase; shape; beta; memory; shape memory; temperature; temperatures; martensitic transformation; gamma; transformation temperatures; effect; thermal	Martensitic phases in Cu-Zn-Al alloys have close packed structures which can be described as a face centred tetragonal (fct) lattice into which stacking faults are periodically inserted every second or third close packed plane. The tetragonality cia of the fct cell is an important parameter which is related to the martensitic transformation temperature to the parent B2 or L2(1) phase. When diffusion is allowed in the martensitic phases, a process of stabilisation takes place. This process results in an increase of the transformation temperature to the parent phase and involves changes in the tetragonality of the fct cell. In order to study the tetragonality of the martensitic phases in Cu-Zn-Al alloys, the large-angle convergent beam electron diffraction (LACBED) technique is used. Different LACBED patterns are obtained to find an adequate orientation for the determination of the tetragonality, and its evolution during stabilisation. The results are compared with X-ray measurements available in the literature. The accuracy of the method and its applicability to the study of stabilisation processes are discussed.
10.1016-S0921-5093(99)00309-3	4	transformation; martensite; martensitic; phase; shape; beta; memory; shape memory; temperature; temperatures; martensitic transformation; gamma; transformation temperatures; effect; thermal	The paradoxical decrease of the one way (OWSME) and the two-way shape memory effect (TWSME) with increasing volume fraction of martensite in dual phase microstructure obtained by quenching from dual phase equlibrium field alpha/beta in a Cu-Zn-Al alloy presented at Icomat '95 is re-evaluated. It is also found that TWSME degradation by thermal cycling increases with decreasing volume fraction of martensite. Both phenomena are accompanied by changes in degree of order in martensite, solution hardening of the alpha-phase and the stacking fault energy of martensite. They seem to be caused by the synergetic effect of changes in the stacking fault energy of martensite and solid solution hardening of the alpha-phase.
10.1016-S0921-5093(99)00334-2	4	transformation; martensite; martensitic; phase; shape; beta; memory; shape memory; temperature; temperatures; martensitic transformation; gamma; transformation temperatures; effect; thermal	The effect of composition on the microstructural evolution after fatigue is presented for Cu-Zn-Al single crystals. Fatigue associated to stress-induced martensitic transformations has been shows to induce several types of defects in poly and single crystals of Cu-Zn-Al alloys, the grain boundaries playing the main role in the polycrystals. In this work attention is paid to the formation of defects on the surface and in the bulk for single crystals of different compositions, and similar defects to those found for transformation temperatures M(s), around room temperature and e/a = 1.48 are seen for e/a = 1.43 but after a much smaller number of cycles. However, changes in the mechanical behavior are not observed at least up to 1000 cycles, even though the changes on the surface and in the bulk for the latter composition are striking.
10.1016-S0921-5093(99)00335-4	4	transformation; martensite; martensitic; phase; shape; beta; memory; shape memory; temperature; temperatures; martensitic transformation; gamma; transformation temperatures; effect; thermal	Cu-Based shape memory alloys were developed in the 1960s. They show excellent thermoelastic martensitic transformation. However, the problems in mechanical properties and thermal instability have inhibited them from becoming promising engineering alloys. A new Cu-Zn-Al-Mn-Zr Cu-based shape memory alloy has been developed. With the addition of Mn and Zr, the martensitic transformation behaviour and the grain size can be better controlled. The new alloy demonstrates good mechanical properties with ultimate tensile strenght and ductility, being 460 MPa and 9%, respectively. Experimental results revealed that the alloy has better thermal stability, i.e. martensite stabilisation is less serious. In ordinary Cu-Zn-Al alloys, martensite stabilisation usually occurs at room temperature. The new alloy shows better thermal stability even at elevated temperature (similar to 150 degrees C, > A(f) = 80 degrees C). A limited small amount of martensite stabilisation was observed upon ageing of the direct quenched samples as well as the step quenched samples. This implies that the thermal stability of the new alloy is less dependent on the quenching procedure. Furthermore, such minor martensite stabilisation can be removed by subsequent suitable parent phase ageing. The new alloy is ideal for engineering applications because of its better thermal stability and better mechanical properties.
10.1016-S0921-5093(99)00337-8	4	transformation; martensite; martensitic; phase; shape; beta; memory; shape memory; temperature; temperatures; martensitic transformation; gamma; transformation temperatures; effect; thermal	Ausforming implies plastic deformation of austenite (beta) at temperatures T(AF) > M(d), at which no stress- or strain-induced transformation can occur. It introduces a variety of extrinsic lattice defects, which in turn modify the course of transformation, the structure of martensite, and increase the conventional strength of the alloys. The temperature range of ausforming has to be subdivided into three subranges, depending on whether the beta-phase is (1), disordered; (2). ordered; or (3) capable of precipitation of a second phase or massive transformation. For the Cu-base alloys the ranges 1 and 3, and for Ni-Ti 2 and 3 may apply. This causes a different hot-deformation behavior of the two types of alloys: the formation of dislocation groupings (2-d, 3-d-nets, and Moires) in the brass-type alloys which undergo ordering during cooling from T(AF). In addition a particular twinning mechanism and the formation of a rolling texture are found in ordered Ni-Ti. In Ni-Ti-alloys premartensitic R-phase formation can be caused by ausforming. Ausforming leads to lower temperatures but not to suppression of martensitic transformation cycles. Conventional strength is increased in both types of alloys.
10.1016-S0921-5093(99)00352-4	4	transformation; martensite; martensitic; phase; shape; beta; memory; shape memory; temperature; temperatures; martensitic transformation; gamma; transformation temperatures; effect; thermal	The distortion of the atomic lattice is determined using a recently developed method of analysing high resolution electron microscope images. The analysis is carried out in terms of the individual lattice fringes which contribute to the image contrast. A perfect set of fringes has an amplitude and phase given by the corresponding Fourier component. A distorted lattice can be analysed by introducing the concept of a 'local' Fourier component, representing the local values of amplitude and phase as a function in position of the image. The local phase is used to determine the line of a perfectly coherent interface between two sets of lattice planes. The degree of self-accommodation of a series of martensitic plates in a Cu-Zn-Al shape-memory-alloy is studied by the phase analysis of an experimental high resolution image.
10.1016-S0921-5093(99)00355-X	4	transformation; martensite; martensitic; phase; shape; beta; memory; shape memory; temperature; temperatures; martensitic transformation; gamma; transformation temperatures; effect; thermal	Tension/compression thermomechanical experiments were performed on oriented Cu-Al-Ni shape memory alloy single crystals. Response of the single crystals in thermomechanical loads was strongly temperature dependent and anisotropic, i.e. dependent on the orientation of the load axis and sense of the load. The anisotrophy of the response is closely related to an anisotropy of the transformation strains due to two basic martensitic transitions beta(1)-->beta(1)' and beta(1)-->gamma(1)' in Cu-based alloys. Calculated transformation strains due to these transitions were compared with the results of compression experiments. The comparison explains well the observed anisotropy of the response of the crystals in thermomechanical loads, in particular, the experimentally observed anisotropy in transformation strains, stresses, hysteresis widths, slopes of transformation lines in stress-temperature diagrams and martensite phases formed under various stress-temperature conditions.
10.1016-S0921-5093(99)00369-X	-1		The transformation between the alpha (fcc) and beta (bcc) equilibrium phases at elevated temperatures is compared with that between the long range ordered B2 phase and the martensite at low temperatures, taking the Cu-Zn system as a prototype. The low temperature vibrational entropy difference, as measured from the martensitic transformation, is extrapolated to elevated temperatures at which disordered alpha and beta are stable. This makes it possible to compare the corresponding enthalpy differences and deduce pair interchange energies, which depend only on pair distance but not on the crystal structure. This result is consistent with the observation that in many alloys based on the noble metals the enthalpy difference between the equilibrium structures is controlled mainly by the electron concentration ela although the much larger mixing enthalpy of each of these structures depends strongly on the specific system. It also permits to evaluate the short range order (SRO) contribution at elevated temperatures using the cluster variation method. It is shown that the Gibbs free energies due to SRO are almost the same in the alpha and beta phases although they are non-negligible.
10.1016-S0921-5093(99)00370-6	4	transformation; martensite; martensitic; phase; shape; beta; memory; shape memory; temperature; temperatures; martensitic transformation; gamma; transformation temperatures; effect; thermal	The phenomenological theories for martensitic transformation by Wechsler, Lieberman, Read and Bowles, Mackenzie describes well the crystallography and orientation relationship between austenite and martensite by postulating an undistorted habit plane. However, they do not give information on the actual path of the atomic displacements during the martensitic transformation. An atomistic model which attempts to do that and results in the same crystallography as in the phenomenological models has previously been described for the transformation from the bcc to the fee structure by one of the authors. In this model the main shear occurs on the bcc(110)(beta) < 1 (1) over bar 0 >(beta) plane, to which a shuffle on an inclined plane is added. Because both steps could never be separated experimentally, the model remained speculative. It has now been possible to show that an intermediate structure which consists only of shears on (110)(beta) < 1 (1) over bar 0 >(beta) can be obtained by the dezincification of beta phase Cu-Zn alloys in the form of coherent spherical particles with the 4H structure. Its appearance proves that this structure has a sufficiently low free energy to serve also as the first step in the martensitic transformation, in which its energy can be decreased further by the shuffles.
10.1016-S0921-5093(99)00378-0	-1		We report results on a finite element simulation of a needle-like martensitic microstructure observed in biaxial loading experiments conducted by Chu and James on single crystals of the shape-memory alloy Cu-14 at% Al-3.9 at% Ni. This microstructure was observed near an interface between twinned layers of two variants and a pure variant of martensite. We used a geometrically nonlinear theory of martensite to model and compute the complex microstructure by energy minimization with a boundary condition that is compatible with the microstructure. Our computational model has yielded multiple metastable states that depend on the initial state of our energy-minimizing iteration. The simulated twinned layers form branches and bend as they approach the laminate-single variant interface in good agreement with the experiment of Chu and James.
10.1016-S0921-5093(99)00420-7	4	transformation; martensite; martensitic; phase; shape; beta; memory; shape memory; temperature; temperatures; martensitic transformation; gamma; transformation temperatures; effect; thermal	The Cu-Zn-Al alloys with relatively small hysteresis(< 10 K) have been produced for the wire drawing and spring production for special applications. Response of the functional properties under various schemes of the transformation cycles is studied in detail in the final product form. Namely, the shift in the transformation temperatures and the features of the hysteresis loop observed in experiments with the stroke versus temperature dependence are analyzed as a function of the number of the full and partial transformation cycles. Degradation of the shape memory parameters with multiple transformation cycles occurs presumably in partial transformation cycles in the constrained condition. The behavior of the material in the transformation cycles under load is compared with the transformation cycles in the stress-free condition in order to propose finally the training scheme to reach optimal functional properties.
10.1016-S0921-5093(99)00432-3	4	transformation; martensite; martensitic; phase; shape; beta; memory; shape memory; temperature; temperatures; martensitic transformation; gamma; transformation temperatures; effect; thermal	The isothermal aging effects in some beta Cu-Zn-Al alloys containing between 9.98 and 16.33 at% Al and a constant electron per atom ratio, e/a, of 1.48, were studied by optical and electron microscopy and time dependence of microhardness and electrical resistivity in the temperature range of 473 and 773 K. On aging, for all compositions, the beta phase decomposes into a mixture of (alpha + gamma) phases, with an earlier formation of gamma phase in alloys with higher Al content. The hardness and the electrical resistivity increase with aging time at each temperature, but the causes of these changes are not the same: the hardness variations are associated mainly with the gamma precipitation while the resistivity changes are related to the eutectoid decomposition.
10.1016-S0921-5093(99)00434-7	4	transformation; martensite; martensitic; phase; shape; beta; memory; shape memory; temperature; temperatures; martensitic transformation; gamma; transformation temperatures; effect; thermal	In this paper the effect of quenching from different temperatures (T-q) in a Cu-Al-Mn alloy is studied. This alloy system, which displays an L2(1) ordered structure, transforms martensitically at an intermediate temperature T-M, and undergoes a spin freezing process at a lower temperature T-f. Positron annihilation measurements have shown that after the quench, an excess of vacancies is retained in the system, depending on T-q. In addition, both T-M and T-f have been found to be sensitive to T-q. This has been attributed to frozen-in disorder induced by the quench . Experimental results have been interpreted in terms of the growth of magnetic clusters, quenched-in vacancies and atomic disorder.
10.1016-S0921-5093(99)00437-2	4	transformation; martensite; martensitic; phase; shape; beta; memory; shape memory; temperature; temperatures; martensitic transformation; gamma; transformation temperatures; effect; thermal	The influence of diffusion on the two way shape memory effect (TWME) in Cu-Zn-Al polycrystals has been studied. The excess vacancy concentration which controls the diffusion velocity has been monitored by different heat treatments: (a) a slow air cooling and aging in the austenite prior to the transformation, leading to a low vacancy concentration; (b) a quench from 800 degrees C; and (c) a quench from 300 degrees C with an increase in the excess vacancies. The TWME has also been studied at low temperatures where diffusion is absent. All these results show that in Cu-Zn-Al polycrystals, diffusion has little or no influence on the TWME, and that instead a spectrum of martensite plate configurations is created by the stress, which then serve as nuclei for the subsequent transformation without an applied stress. The TWME obtained in the polycrystals is in all cases lower than that in single crystals after the stabilization of the stress induced martensite variant.
10.1016-S0921-5093(99)00438-4	4	transformation; martensite; martensitic; phase; shape; beta; memory; shape memory; temperature; temperatures; martensitic transformation; gamma; transformation temperatures; effect; thermal	The two way shape memory effect (TWSME) was induced in Cu-Al-Ni single crystals by a training method which consisted of applying tensile or compressive stresses at room temperature and keeping the sample under stress in the martensitic phase at the same temperature for a certain time. After quenching from the beta stability region the studied alloys exhibit a simultaneous transformation to beta'(18R) and gamma' (2H) martensites. Subsequent ageing in the beta phase favours the formation of the gamma' phase. An important improvement of the TWSME has been obtained both in the tension and compression modes in the samples aged at 470 K before training, coincident with a transformation predominantly to the gamma' martensitic phase. In trained samples, a subsequent heating for short times at 520 K produces a stable and maximum TWSME of 4% always in elongation sense, both for the samples trained in tension and compression mode.
10.1016-S0921-5093(99)00439-6	4	transformation; martensite; martensitic; phase; shape; beta; memory; shape memory; temperature; temperatures; martensitic transformation; gamma; transformation temperatures; effect; thermal	The two-way shape memory effect (TWME) has been induced by thermomechanical cycling in Cu-Zn-Al alloys using a dedicated hydraulic mechanical testing soft machine with complete computer control of force, elongation and temperature. The results concerning single crystals (composition Cu-16.9 wt% Zn-7.7 wt% Al, nominal M(s) of 273 K) and polycrystals (Cu-15.8 wt% Zn-8.3 wt% Al, nominal M(s) of 230 K, mean grain size of 1 mm) are reported for two training protocols (sequence of one thermomechanical cycle of education followed by one stress free thermal cycle to check the TWME or twenty consecutive thermomechanical cycles followed by one or two checking thermal cycles). The capacity of the trained specimen for producing work under an antagonist compressive stress is also studied and the behaviour of the deformation of the specimen under such a condition at different temperatures is analysed in terms of a competition between the contributions of the different variants: trained variants with an intrinsic deformation in the direction of the tensile stress of the training process, trained variants with an intrinsic deformation which is not well orientated with respect to this direction (in the polycrystal) and new variants with an intrinsic deformation in the direction of the compressive stress which can replace the educated variants.
10.1016-S0921-5093(99)00551-1	-1		Dispersion strengthened Cu alloys have been manufactured by conventional spray forming and also by reactive spray forming, followed by hot extrusion of the spray deposited billets. In this work, we have systematically investigated the relationship between the microstructure and mechanical properties of the Cu alloys fabricated through two techniques by means of optical microscopy (OM), scanning electron microscopy (SEM), transmission electron microscopy (TEM), and tensile testing. The size of dispersed particles in the reactive spray formed alloy was much finer than that in the conventionally spray formed alloy. That was because the dominant chemical reaction between Ti and B had occurred in Cu-Ti-B alloy melt in conventional spray forming while it had occurred after deposition of droplets in reactive spray forming. The yield strength of the reactive spray formed alloy was greater than that of the conventional spray formed alloy in spite of a lower volume fraction of reinforced particles. To understand the mechanism responsible for this experimental observation, the yield strength of the two Cu alloys were analyzed using the dislocation pile-up model and Orowan mechanism, which were fairly consistent with the experimental results. Increase in yield strength of reactive spray formed alloy compared with that of conventional spray formed alloy was largely attributed to nanoscale TiB dispersoids. This indicates that refining the reinforced particle size to nanoscale is of special importance for the development of high strength Cu alloys since the yield strength predominantly depends on the size and volume fraction of the reinforcement. From this point of view, reactive spray forming can be considered as a new promising process to develop high strength Cu alloys.
10.1016-S0921-5093(99)00752-2	16	wear; composite; composites; powders; milling; particles; powder; wt; sliding; friction; hardness; matrix; mechanical; surface; properties	Pure copper and its composites reinforced with TiB2 particles were prepared by a hot isostatic pressing process. The two-body abrasive wear behavior of these specimens was investigated using pin-on-disk method where the sample slid against a SiC abrasive of 240-grit size. Pure copper exhibits a high abrasive wear loss because of its softness. The addition of only 5 vol.% TiB2 particle to copper leads to a dramatic improvement in its wear resistance. The wear resistance increases by further increasing volume fraction of reinforcing particles that resist the microcutting action of SiC abrasives.
10.1016-S0921-5093(99)00792-3	4	transformation; martensite; martensitic; phase; shape; beta; memory; shape memory; temperature; temperatures; martensitic transformation; gamma; transformation temperatures; effect; thermal	Calorimetric measurements have been carefully performed on four kinds of Cu-Zn-Al samples, arising from the combination of different martensitic structures and from the presence or not of grain boundaries. The differences found in the transformation behaviour, characteristic transformation temperatures and in the corresponding thermodynamic properties (enthalpy and entropy changes) have been analyzed. The remarkable finding was that the transformation to 2H in the polycrystalline samples couldn't go on completion. On the other hand, this behaviour was not observed for the transition to 18R, within the experimental scatter. Published by Elsevier Science S.A.
10.1016-S0924-0136(01)00715-4	6	grain; deformation; strain; strength; dislocation; cu-; tensile; size; ecap; grain size; sfe; ductility; hardening; high; stress	Bundling and drawing processing was used to produce high strength large diameter Cu-Nb wires for magnet applications. The microstructure and mechanical properties of bundled heavily drawn Cu-Nb wires were examined. The strength increased gradually with increasing Nb content while the ductility was insensitive to Nb content. The ratios of yield stresses are found to be close to those of Young's moduli in various Cu-Nb microcomposites, suggesting that the strength is primarily controlled by athermal obstacles. The fracture morphologies show ductile fractures irrespective of Nb contents. Secondary cracking along the interfaces between sub-elemental wires was occasionally observed and the frequency of secondary cracking increased with increasing Nb content. Secondary cracks due to debonding along the interface between sub-elemental wires were also observed to be more frequent at 295 K than at 75 K. The more frequent debonding at 295 K may be due to relatively large triaxial stress state caused by more localized necking of sub-elemental wires.
10.1016-S0924-0136(02)00137-1	-1		In this study, the effect of phosphorus on microstructure and mechanical properties of leaded-tin bronze was investigated by using scanning electron microscope (SEM), energy dispersive spectroscopy (EDS), X-ray diffraction techniques, and tensile, fatigue and adhesive wear tests. It was observed that phosphorus prevented the growth of (Zn, Cu)S, which is a brittle and undesirable phase, by surrounding its environment, and therefore it increased the fatigue life and tensile strength of the material significantly, but it decreased the wear resistance of the material by increasing the mass loss at the initial stage of wear. It was concluded that the leaded-tin bronzes containing phosphorus can be preferred in manufacturing machine elements in which fatigue life is important. (C) 2002 Published by Elsevier Science B.V.
10.1016-S0924-0136(97)00426-3	-1		The electro-optical properties of semiconductors including Cu(In, Ga)Se-2 compounds suffer from various types of intrinsic defect levels such as grain boundaries and dislocations. The type and number of these can vary considerably, depending on the various aspects of the fabrication processes of the semiconductors. However, the properties of the material can be improved significantly by employing post-deposition procedures. This paper presents results of studies carried out on the post-deposition thermal annealing of flash evaporated thin films of Cu(ln, Ga)Se,. The structural and electro-optical properties were analyzed using a variety of analytical techniques, including X-ray diffraction (XRD), scanning electron microscopy (SEM) and Rutherford backscattering (RBS). A high resolution near-infrared photoacoustic spectrometer has also been employed to assess improvements in the optical properties following thermal annealing and correlated with the crystallite structure. Results obtained for thin films of CIGS were compared to data gained from studies carried out on single crystals.
10.1016-S0924-0136(99)00381-7	4	transformation; martensite; martensitic; phase; shape; beta; memory; shape memory; temperature; temperatures; martensitic transformation; gamma; transformation temperatures; effect; thermal	Rapidly liquid quenched Cu-Sn ribbons were produced and their shape memory properties and oxidation behaviour investigated using thermal analysis, metallography and X-ray diffraction methods. During the heating regime from -70 degrees C to room temperature in a DSC instrument, martensite --> austenite transformation was performed and the A(s) and A(f) temperatures were determined as-16.4 degrees C and -8.4 degrees C respectively. The oxidation behaviour was also determined using TGA. The total oxidation percentages decreased with increasing heating rate, whereas the oxidation rate increased with the heating rate during the heating and cooling times. The shape memory behaviour of the ribbon samples were also seen after bending in liquid nitrogen and reheating to room temperature.
10.1016-S0925-8388(00)00958-0	4	transformation; martensite; martensitic; phase; shape; beta; memory; shape memory; temperature; temperatures; martensitic transformation; gamma; transformation temperatures; effect; thermal	The internal friction spectra of a martensitic transformation obtained as a function of temperature with (T) over dot not equal 0, consists of three different contributions: transitory, phase transition, and intrinsic. In order to get a more quantitative information from these internal friction spectra, such as the volume fraction of transformed material, it is necessary to separate the spectra in their different contributions. This paper proposes a new method which allows to analyse the IF spectra. The new procedure is based on the strong dependence of the transitory term on the temperature rate. Thus, the separation of the three different contributions to the IF is completed starting from several IF spectra carried out at different temperature rates. Using this method it is possible to check the validity of the different models proposed in the literature for the explanation of the transitory term. Along with the presentation of the method, its application to a thermoelastic Cu-AI-Ni shape memory alloy is shown.
10.1016-S0925-8388(00)00959-2	4	transformation; martensite; martensitic; phase; shape; beta; memory; shape memory; temperature; temperatures; martensitic transformation; gamma; transformation temperatures; effect; thermal	The internal friction has been measured under isothermal conditions over a large frequency range (10(-3) to 40 Hz) in a Cu-13.2Al-3Ni (wt%) single crystal at temperatures between 293 and 473 K, including the martensitic transformation. On one hand, atypical behavior was revealed in the martensitic state. Indeed, the damping level measured at low frequency, below his, is much more important when it is determined under cooling conditions than on heating. On the other hand, a high damping level was observed in a very narrow temperature range during direct transformation. This last effect was ascribed to the nucleation process of the martensite, whereas a freeze in interface motion could be responsible for the thermal asymmetric behavior.
10.1016-S0925-8388(00)01019-7	4	transformation; martensite; martensitic; phase; shape; beta; memory; shape memory; temperature; temperatures; martensitic transformation; gamma; transformation temperatures; effect; thermal	The present work continues the series of experimental investigations undertaken in order to elucidate the mechanisms controlling elastic and anelastic properties of the beta(1)' martensitic phase of Cu-based shape memory alloys. The paper reports an attempt to distinguish between 'dislocation' and 'interface' mechanisms of the internal friction in the beta(1)' martensitic phase of Cu-Al-Ni single crystals. Two types of experiments have been performed. First, the ultrasonic strain amplitude-independent and amplitude-dependent internal friction (ADIF) of a monovariant specimen for temperatures 90-300 K is carefully re-examined. Second, in situ measurements of the ADIF and of the influence of ultrasonic oscillations on the plastic deformation (acoustoplastic effect) were carried out during quasistatic deformation of a quenched polyvariant specimen. Experimental results support a dislocation rather than an interface mechanism of anelasticity, at least at ultrasonic frequencies and moderate strain amplitudes.
10.1016-S0925-8388(00)01268-8	4	transformation; martensite; martensitic; phase; shape; beta; memory; shape memory; temperature; temperatures; martensitic transformation; gamma; transformation temperatures; effect; thermal	The influence of the disordered (Cu)-alpha phase in the isothermal aging kinetics of the Cu-19 at%Al alloy was studied using microhardness measurements, optical and scanning electron microscopy and X-ray diffractometry. The results indicate that the beta'-->(alpha+gamma (1)) decomposition reaction rate increases with the increase of the temperature in the range between 150 and 500 degreesC and at 600 degreesC the reaction is delayed by the alpha phase precipitation. The value obtained for the activation energy indicates an interface diffusion controlled reaction.
10.1016-S0925-8388(01)01301-9	9	magnetic; magnetization; magnetoresistance; temperature; superparamagnetic; annealing; gmr; field; magnetic properties; ferromagnetic; granular; samples; magnetic field; melt-spun; particles	Recent studies of mechanically alloyed Fe-Cu powder mixtures have suggested differences in the local magnetic environment of iron atoms. For a more accurate definition of this point, ball-milled Cu70Fe30 and Cu50Fe50 alloys were investigated by Mossbauer spectroscopy in the, temperature range 4.2-300 K. The low temperature Mossbauer spectra exhibit a broad magnetic pattern. typical of a defect structural configuration. The magnetic splitting strongly decreases with increasing temperature, especially in the case of Cu70Fe30 alloy. But even for this composition there is, at room temperature, an unresolved magnetic pattern. Applying a magnetic field of 3 T, parallel to gamma rays, at 4.2 K a rotation of all magnetic moments along the external field is observed. The samples behave as an alloy with continuously distributed local fields.
10.1016-S0925-8388(01)01314-7	9	magnetic; magnetization; magnetoresistance; temperature; superparamagnetic; annealing; gmr; field; magnetic properties; ferromagnetic; granular; samples; magnetic field; melt-spun; particles	Ca-Co granular films have been prepared by galvanostatic dc electrodeposition in a single sulphate bath . The magnetoresistance ratio (MR={(R-H-R-Q)/R-0}X100) increased with increase in annealing temperature until 450 degreesC, beyond which NM starts decreasing Lower coercivity values along with non-saturating behaviour of the room temperature magnetization curves indicated the presence of an appreciable amount of superparamagnetic clusters. The average cluster size was calculated by fitting the superparamagnetic component of mag-spherical shape) was calculated to be 1.87 nm for magnetization to Langevin equation. The average radius of the Co clusters (assuming as-deposited film and 1.57 nm for a film annealed at 400 degreesC for 1 h . The lowering of average cluster size with increase in annealing temperature in the metastable films is attributed to the segregation of many new (smaller) Co clusters.
10.1016-S0925-8388(01)01860-6	16	wear; composite; composites; powders; milling; particles; powder; wt; sliding; friction; hardness; matrix; mechanical; surface; properties	Cu-Nb composites have come into prominence because of their high strength and high electrical conductivity. A number of preparative techniques have received attention among the investigators due to difference in melting point, density and crystal structure of the constituents. In the present paper a simple, easy to scale up, non-furnace process involving co-reduction of mixed oxides (CuO, Nb2O5) with aluminium in the presence of slag fluidizer CaO has been attempted to prepare a Cu-2.5Nb (wt%) composite. A typical charge composition of about 58.2% CuO, 3.5% Nb2O5 23.3% CaO and 15% Al (specific heat 715 kcal/kg) resulted in a Cu-Nb product with 83% yield of nearly targeted composition. As reduced composite was homogenized by arc melting. Remelted and consolidated composite was drawn into wires of <0.5 nun diameter to convert the dendritic niobium phase into the filamentary form. Property evaluation studies such as optical metallography, hardness, electrical resistivity measurements etc. have been carried out.
10.1016-S0925-8388(02)00983-0	-1		The standard enthalpies of formation of some noble metal-transition metal compounds have been measured by high temperature direct synthesis calorimetry at 1372 K. The following results (in kJ/mol of atoms) are reported; Cu51Zr14, -24.3+/-2.2; Cu3Pd, -7.6+/-1.2; Cu51Hf14, -22.9+/-2.3; Cu3Pt, -10.8+/-1.1; AgTi, -1.6+/-2.4; AgTi2, -2.3+/-1.1; Ag2Y, -26.6+/-1.2; Au2Sc, -83.4+/-1.8; Au4Sc, -57.3+/-1.5; AuMn, -25.3+/-1.7; Au2Y,-84.6+/-1.8; Au3Y, Pd, -69.1+/-1.9; Au3Pd, -7.9+/-1.9. The results are compared with some earlier experimental values obtained by EMF, by vapor pressure and by calorimetry. They are also compared with the predicted values of Miedema and coworkers. We will present a systematic picture of how the enthalpies of formation may be related to the atomic number of the transition metal.
10.1016-S0925-8388(02)01275-6	-1		Anelastic relaxation from hydrogen in metals may be subdivided into mechanisms of long-range diffusion, short-range reorientation, and processes coupled with motion of matrix defects. Among recent discoveries in this field, i.e. Snoek-type effects in quasicrystals, Zener mechanism in intermetallic compounds, and intercrystalline Gorsky effect, the latter two are studied in a combined way using different polycrystalline Zr-Cu(-Ni-Al) alloys with CuZr2-type structure. This combined approach, concerning kinetics as well as concentration-dependent magnitudes of the respective damping peaks, is helpful for a better understanding of both processes. The results generally confirm the two mechanisms considered, but also give some new insight, for example, into the probable influence of an attractive H-H interaction on the Zener mechanism. The potential of these new effects for different kinds of application is also discussed briefly.
10.1016-S0925-8388(03)00020-3	4	transformation; martensite; martensitic; phase; shape; beta; memory; shape memory; temperature; temperatures; martensitic transformation; gamma; transformation temperatures; effect; thermal	The influence of additions of 2, 4, 6, 8, 10 and 12 wt% Ag in the isothermal aging kinetics of the Cu-8 wt% Al alloy was studied using microhardness measurements, differential scanning calorimetry, optical and scanning electron microscopy and X-ray diffractometry. The results indicate that the presence of silver is responsible for the shift of the equilibrium concentration to higher Al contents, allowing the formation of the gamma(1) phase (Al4Cu9) in this alloy. For Ag additions up to 6% the dominant kinetic process is Ag precipitation and for additions from 8 to 12% Ag the nucleation of the perlitic phase dominates.
10.1016-S0925-8388(03)00264-0	4	transformation; martensite; martensitic; phase; shape; beta; memory; shape memory; temperature; temperatures; martensitic transformation; gamma; transformation temperatures; effect; thermal	The internal friction (IF) of Johnson alloy (Zr-Ti-Cu-Ni-Be) glass prepared by a single-roller melt-spinning method was measured using an inverted torsion pendulum with the free decay method. The measurements were performed from room temperature, through the glass transition temperature T-g, up to the crystallization temperature T-x. The effect of isothermal annealing at a temperature about 20 K below T-g was studied. By the annealing the unstable glassy state and the metastable supercooled state were transferred to more stable ones (stabilization). In a well-stabilized state, the background IF was flat at lower temperatures, increased rapidly at higher temperatures, and an IF peak appeared near T-x together with another peak at a lower temperature. No IF peak was observed near T-g. Qualitative discussions are presented for the experimental results, and possible use of the glass as a high damping material is briefly mentioned.
10.1016-S0925-8388(03)00634-0	-1		Nanostructured Cu-Nb composites are prepared by mechanical alloying and a subsequent heat treatment. Up to 10 at% Nb can be brought into solid solution by milling for 30 h at liquid nitrogen temperature. Subsequent to mechanical alloying a heat treatment was applied to precipitate the nobium from the solid solution in order to enhance both strength and conductivity of the material. The atmosphere present during the milling process strongly influences the phase formation. A high oxygen content within the powder leads to the formation of niobium oxide during the late state of milling and, later, prevents the formation of nobium precipitates by heat treatment. This occurs only in powder with a low oxygen content. A temperature of 400degreesC proves to be the optimum for strength, but too low to enhance the conductivity by complete precipitation of the Nb atoms. Almost all the nobium precipitates from the solid solution at 900 degreesC, but recrystallisation takes place at this temperature. Thus, the optimum heat treatment produces a balance between the mechanical and electrical properties and should be in the range of 600-700degreesC.
10.1016-S0925-8388(03)00738-2	0	solidification; phase; magnetic; magnetic field; undercooling; field; liquid; separation; peritectic; immiscible; cu-; dendrite; phase separation; microstructure; primary	A Cu-31% Sb eutectic: alloy has been rapidly solidified during containerless processing in a drop tube. The microstructures are characterized by betaCu(3)Sb grains plus a small amount of alphaCu solid solution formed at the grain boundaries, instead of cooperative growth into a eutectic like other binary eutectic: alloys. With the decrease of droplet size, betaCu(3)Sb grain is refined and equiaxed grain of alphaCu solid solution forms in droplets. Melt undercoolings up to 225 K (0.245T(E)) are estimated by a heat transfer model of droplet solidification. Both experimental and calculated results indicate that, as undercooling rises, the nucleation rate Of betaCu(3)Sb intermetallic compound increases. The growth velocities of eutectic structure and dendrites of betaCu(3)Sb and alphaCu increase with rising undercooling. The growth Of betaCu(3)Sb phase is dominant when undercooling is lower than 53 K. When undercooling exceeds 53 K, the growth dominance of the betaCu(3)Sb phase will be replaced by the alphaCu phase. In contrast, the growth of lamellar eutectic can never become dominant in undercooled melt. This is just the reason why a eutectic microstructure cannot be formed in Cu-31% Sb eutectic alloy during rapid solidification. Microstructural evolution of betaCu(3)Sb grain dominates the microstructure of Cu-31% Sb eutectic alloy.
10.1016-S0927-0256(00)00013-6	-1		The stability of Cu-Zn-Al was studied by total-energy calculations using the KKR-CPA method. Mixing and elastic and chemical energies, solubility lines, and Fermi surfaces were computed for the fee and bcc structure. We find that the martensitic transformation can be considered as a transition from a disordered bcc to a disordered fee structure. Fermi-surface nesting leads to DO23 ordering while the van Hove singularities contribute to the instability of the fee structure.
10.1016-S0927-0256(00)00136-1	-1		The Portevin-LeChatelier (PLC) effect with characteristic temporal instabilities in the recorded stress is closely associated with local inhomogeneities of deformation. Measurements on Cu-10 at% Al and 15 at% Al polycrystals by means of a novel laser scanning extensometer, which provides quasi-simultaneous spatial resolution along the main part of the specimen, have been used for an unambiguous characterization of the PLC deformation bands of type A (continuous propagation of single band along the specimen), type B (discontinuous band propagation) and type C (stochastic nucleation of single bands along the specimen), supplementing and correcting the common characterization from the load serrations. Surprising transitions between the types have been detected in the effective stress versus temperature (or versus strain rate) diagram. The parameters of type A bands (local band strain, band width, propagation rate) have been measured at various temperatures in dependence of grain size, specimen thickness and imposed deformation rate, and are compared with predictions of a recent theoretical treatment.
10.1016-S0927-0256(02)00405-6	-1		The nucleation and propagation of Portevin-LeChatelier (PLC) deformation bands in Cu-15at%Al have been studied by means of a novel multi-zone scanning laser extensometer providing information on the development of local strain along the main part of the specimen, in addition to the conventional measurement of stress serrations. By means of tensile tests with imposed constant strain rate independent data have been determined on propagation velocity, concentrated strain and width of the bands appearing in three different types of PLC-deformation. The tensile test machine has been softened to permit measurements with imposed constant stress rate. First results will be presented and compared to the strain-controlled ones on Cu-15at%Al.
10.1016-S0928-4931(02)00212-6	2	corrosion; surface; film; electrochemical; films; spectroscopy; layer; current; solution; potential; resistance; composition; x-ray; ions; showed	This contribution reports on the formation of coating surfaces of mirror polished Cu-Ni alloy (here Cu55Ni45) substrates by self-assembling monolayers of n-dodecanethiol molecules. X-ray photoelectron spectroscopy (XPS), contact angle and electrochemical polarisation curve measurements have been carried to assess the extent and the quality of the modifications. Good quality monolayers are obtained for electrochemically reduced substrates reacted for 2 h in 10(-1) M solutions of n-dodecanethiol in ethanol.
10.1016-S0955-2219(03)00294-2	-1		The experimental study of the wetting phenomena in the boron carbide-copper system, using the sessile drop method at 1150 degreesC shows that molten Cu attacks boron carbide substrates forming a crater below the contact area. Boron additions prevent crater formation, improve wetting and, for a 10 at% B alloy, reduce the equilibrium wetting angle to 40degrees. Thermodynamic analysis of the Cu-B-C system in the Cu-rich corner confirms the experimental results. These results and similar ones obtained in the TiC-Cu system suggest that the presence of a carbide phase over a concentration range is a key feature that governs wetting phenomena and chemical interaction at these metal-carbide interfaces.
10.1016-S0965-9773(97)00096-2	6	grain; deformation; strain; strength; dislocation; cu-; tensile; size; ecap; grain size; sfe; ductility; hardening; high; stress	Creep tests were carried out over a range of temperatures (0.24-0.64 T-m) and stresses on samples of nanocrystalline Cu, Pd, and Al-Zr made by inert gas condensation and compaction. The measured creep rates are two to four orders of magnitude smaller than the values predicted by the equation for Coble creep. At moderate temperatures, the creep rates are comparable or lower than the corresponding coarse-grain rates. Except for the tests performed at the highest homologous temperatures, all creep curves can be fit by the equation for logarithmic creep. The samples in the as-prepared state are highly twinned, and it is believed that the prevalence of low-energy grain boundaries together with inhibition of dislocation activity caused by the small grain sizes are responsible for the low strain rates. (C) 1997 Acta Metallurgica Inc.
10.1016-S0965-9773(99)00260-3	9	magnetic; magnetization; magnetoresistance; temperature; superparamagnetic; annealing; gmr; field; magnetic properties; ferromagnetic; granular; samples; magnetic field; melt-spun; particles	The internal friction as a function of temperature and the giant magnetoresistance for varying magnetic field have been measured on Cu90Co10 ribbons obtained by planar flow casting with different quenching rate. The results are discussed considering the presence of quenched-in Co precipitates in the Cu matrix of the as-cast ribbons and different levels of dispersion of Co in the Cu matrix in the two cases. (C) 1999 Acta Metallurgica Inc.
10.1016-S0966-9795(00)00008-X	4	transformation; martensite; martensitic; phase; shape; beta; memory; shape memory; temperature; temperatures; martensitic transformation; gamma; transformation temperatures; effect; thermal	An anomalous temperature dependence of the yield stress in the ordered CuAu alloy was detected. Blocked <101] superdislocations were observed in the region of the anomalous trend from room temperature to 300 degrees C. Blocking of single dislocations was not detected at these temperatures. The comparison with the known data on the TiAl intermetallic was carried on. The causes of the nonmonotonous temperature dependence of the yield stress with two extremum points were analyzed. The set of possible states of dislocations in TiAl was discussed. A unified scheme with account of mutual dislocation transitions was proposed for the description of the deformation behavior over the whole temperature interval. Specific features of the dislocation structure of CuAu and TiAl were explained. The connection between the brittleness of TiAl and dislocation transformations was discussed.
10.1016-S0966-9795(00)00011-X	4	transformation; martensite; martensitic; phase; shape; beta; memory; shape memory; temperature; temperatures; martensitic transformation; gamma; transformation temperatures; effect; thermal	Gold alloys with around 30 at% copper and 25 at% aluminium undergo a reversible displacive transformation with M-s and A(s) temperatures of about 30 and 75 degrees C respectively. However, the nature of the parent and product phases in this system has not previously been clear. It is confirmed here that the parent phase is a beta electron compound. If it is annealed and quenched, it has ordering intermediate between the A2 and B2 states, and in this case the displacive transformation between the parent phase and the low temperature (martensite) phase is poorly developed, and has some second order characteristics. Ageing of the parent phase causes it to take up L2(1)-type ordering after which the transformation becomes classically displacive and reversible, with many of the characteristics associated with the known shape memory systems. The site occupancies of the parent phase have been estimated.
10.1016-S0966-9795(99)00133-8	4	transformation; martensite; martensitic; phase; shape; beta; memory; shape memory; temperature; temperatures; martensitic transformation; gamma; transformation temperatures; effect; thermal	Currently available shape memory alloys (NiTi, CuAlNi, CuSnAl) lack the high transformation temperatures and long term thermal stability desired in many commercial applications. This paper reports the results of an investigation in which Pd was substituted for Ni to obtain the shape memory ally CuAlPd. The CuAlPd alloys were found to have an austenite transformation temperature range of 115-370 degrees C depending on composition, heat treatment and working process. Optimal shape memory properties were found for a composition of Cu-13.1 wt% Al-2.4 wt% Pd. This alloy has a transformation temperature of 180 degrees C and a recoverable strain of 4.8%. CuAlPd alloys have excellent workability and exhibit fatigue properties comparable to NiTi shape memory alloys. Single crystals of CuAlPd alloys were produced using a modified Bridgeman technique.
10.1016-S0968-4328(03)00025-8	-1		Nanostructures were formed in several conventional materials under single electropulsing, that is nanophases of alpha-Cu(Zn) and beta'-(CuZn) in a cold-worked alpha-Cu(Zn) alloy, nanosized gamma-Fe in a low-carbon steel, nanosized alpha-Al in a superduralumin, and orientated nanosized TiC in a TiC/NiCr cermet. The mechanisms responsible for the above nanostructured transitions can be attributed to the competition of many factors induced by electropulsing, including high-rate heating, thermal stress, reduced thermodynamic energy barrier and high-rate electron impacting. Also, many low-energy dislocation configurations, twins and stacking faults were formed in the copper alloy and cermet under the electropulsing. Such evolution of defects was associated with the electrical, thermal and stress energies induced by the electropulsing.
10.1016-S1001-0521(07)60013-8	8	hot; deformation; strain; strain rate; dynamic; hot deformation; recrystallization; dynamic recrystallization; flow; rate; flow stress; compression; constitutive; degrees; stress	The deformation behavior of dispersion-strengthened copper with different compositions was investigated by hot compression simulation tests on a Gleeble-1500 thermal-mechanical simulator. The microstructure during deformation at high temperature was also studied. The result shows that at the beginning of hot compression simulation, the flowing stress of the dispersion-strengthened copper quickly attains a peak value and the stress shows a greater decrease when the temperature is higher and the strain rate is lower. The dispersion particles lead to an obvious increase in the recrystallization temperature. Under experimental conditions, dynamic recovery is the main softening method. The constitutive equation at high temperature of 1.2%Al2O3-0.4%WC/Cu is obtained.
10.1016-S1002-0721(06)60172-5	15	aging; strength; conductivity; electrical conductivity; electrical; mpa; treatment; strengthening; degrees; cu-; cold; precipitation; tensile strength; tensile; iacs	The effects of B and Cc on the removal of inclusions, microstructures, and properties of Cu-Fe-P alloys were studied. Certain impurity elements and the microstructures, mechanical properties, and conductivity of four experimental alloys, Cu-0.22Fe-0.06P, Cu-0.22Fe-0.06P-0.05Ce, Cu-0.22Fe-0.06P-0.02B, and Cu-0.22Fe-0.06P-0.05Ce-0.02B (%, mass fraction), were tested and analyzed. Results show that on one hand, B and Ce have a remarkable function of removing S, Pb, and Bi from copper alloys; on the other hand, the recrystallization temperature of the Cu-Fe-P alloy is considerably increased by adding trace B and Cc, resulting in the combined strengthening effect of precipitation hardening and cold work hardening after cold working and aging, while the negative effect of B and Ce on conductivity is slight. Therefore, a good combination of high strength and conductivity is achieved.
10.1016-S1002-0721(09)60221-0	2	corrosion; surface; film; electrochemical; films; spectroscopy; layer; current; solution; potential; resistance; composition; x-ray; ions; showed	The amount of Cu coating by chemical plating was investigated based on quadratic regression orthogonal experimental design being adapted to the variation law of temperature, pH value and Ni2+ concentration, and the relevant regression equation was expressed as y=2.1609+0.5295x10(-3)T(2)-0.0342P(2)-0.0265N(2)+0.0023TP+0.0020TH+0.0199PN-0.0959T+0.3814P-0.2073N. The results showed that the deposition rate augmented with the increasing in temperature, pH value and Ni2+ concentration. The experimental parameters of the optimal coating were temperature 75 degrees C, pH value 8.5 and Ni2+ concentration 1.2 g/L. The electrochemical tests indicated that the cycle stability increased from 60.66% to 75.58%, indicating that the treated alloy exhibited better corrosion resistance.
10.1016-S1002-0721(10)60461-9	-1		Cu-14Al-4.5Fc bronze powders with and without 0.6% Ce were prepared and their coatings were fabricated on 45# carbon steel substrate by atmospheric plasma spraying. The effects of rare earth Ce on the coating interface bonding strength, coatings and bonding interface vertical sections microstructure were investigated by tensile machine, X-ray diffraction analysis, scanning electron microscopy (SEM) and electronic probe microanalysis.(EPMA). The results showed that the shape of powders was more spherical like, and the coating's hardness and interface bonging tensile strength would be improved to 8.9% and 17.4%, respectively, higher than that of the Cu-14Al-4.5Fe coating without 0.6% Ce added. The refined of kappa phases, well distributed matrix phases in coatings and the promotion of Fe, Al elements diffusion led to the improvement in interface bonding strength and hardness of the Cu-14Al-4.5Fe coating with addition of 0.6% Ce, which hardened and strengthened the coating.
10.1016-S1002-0721(14)60183-6	-1		As-cast Cu-La alloys with La contents in the range of 0-0.32 wt% were fabricated by vacuum melting method. The effects of La on microstructure and mechanical properties of as-cast pure copper were investigated using optical microscopy (OM), scanning electronic microscopy (SEM), transmission electron microscopy (TEM), X-ray diffraction (XRD) and tensile test. The results showed that La had obvious effects on the solidification microstructure and the grain refinement of as-cast pure copper. With the increase of La content, the ultimate tensile strength, the yield strength and the microhardness increased gradually, but the elongation increased first and then decreased while La content exceeded 0.089 wt%. The improvement of mechanical properties was attributed to the effect of grain refinement strengthening, solid solution strengthening, second phase strengthening and purifying. However, excessive adding La would deteriorate the elongation owing to the excessive Cu6La phases.
10.1016-S1002-0721(14)60421-X	16	wear; composite; composites; powders; milling; particles; powder; wt; sliding; friction; hardness; matrix; mechanical; surface; properties	Sliding friction and wear experiments using Cu-La2O3-graphite composites against Cu-5 wt%Ag alloy ring were conducted at a constant sliding speed of 10 m/s, a current density of 10 A/cm(2) and a load of 2.5 N/cm(2). These composites with different La2O3 and graphite contents were fabricated by hot-pressing. Physical and mechanical properties of the composites were examined. Morphologies of the worn surface of composites were observed using optical microscopy. X-ray photoelectron spectroscopy spectra were used to study compositions of the lubricating film. The results showed that with the increasing addition of La2O3, hardness, flexural strength and electrical resistivity increased, but the relative density dropped. The friction coefficient increased with the increasing addition of La2O3. Composite containing 3 vol.% of La2O3 and 37 vol.% of graphite showed the best wear resistance. The main wear mechanisms of composites were abrasive wear, oxidative wear and adhesive wear.
10.1016-S1002-0721(17)61009-3	-1		Cu-Ag-RE alloys with different Ce contents were prepared by vacuum melting, and microstructure evolution and mechanical properties of Cu-Ag-Ce alloys were investigated by optical microscopy, scanning electronic microscopy with electron backscattered diffraction and tensile test. The results indicated that a columnar to equiaxed transition in cast Cu-Ag-RE alloys was observed due to Ce addition and area of the region with equiaxed grains enlarged with increasing Ce content. Cold-rolled Cu-Ag-RE alloys in annealed condition exhibited a partially or fully recrystallized grain structure depending on the concentration of Ce. The average grain size decreased and texture components changed with increasing Ce content. The main brass-type texture component changed to be copper-type as the Ce content increased from 0.05 wt% to 1.0 wt%. The Cu-Ag-RE alloy with 0.2 wt% Ce showed maximum ultimate tensile strength, while the sample with 1.0 wt% Ce showed a better comprehensive mechanical property.
10.1016-S1002-0721(17)61010-X	-1		The high temperature deformation behaviors and thermal workability of Cu43Zr48Al9 and (Cu43Zr48Al9)(98)Y-2 bulk metallic glasses in the supercooled liquid region were investigated by the uniaxial compression tests. The results showed that the high temperature deformation behaviors were highly sensitive to strain rate and temperature, and the flow stress decreased with the increase of temperature, as well as with the decrease of strain rate. Additionally, the (Cu43Zr48Al9)(98)Y-2 bulk metallic glass displayed smaller flow stress under the same condition. The flow behavior changed from Newtonian to non- Newtonian with increase of the strain rate, as well as the decrease of temperature, which could be explained by the transition state theory. We found that (Cu43Zr48Al9) Y-98(2) bulk metallic glass had better flow behavior than the Cu43Zr48Al9 bulk metallic glass in the supercooled liquid region. In addition, the processing maps of the two bulk metallic glasses were constructed considering the power dissipation efficiency. The optimum domain for thermal workability of the bulk metallic glass was located using the processing map, where the power dissipation efficiency was larger than 0.8. It was shown that the (Cu43Zr48Al9)(98)Y-2 bulk metallic glass, which had larger area of optimum domain, had excellent thermoplastic forming.
10.1016-S1003-6326	-1		A near-alpha Ti-7Al-2V alloy was designed using cluster formula approach and prepared by laser additive manufacturing, whose specific strength is better than that of Ti-6Al-4V alloy. Its composition formula alpha-{[Al-Ti12](AlTi2)}15+fl-{[Al-Ti14](V3)}2 features an enhanced alpha-Ti by increasing alpha unit proportion of 15/17 (with respect to 12/17 of Ti-6Al-4V alloy) and stabilized fl-Ti via V alloying. This alloy possesses a good laser additive manufacturing processibility. At the as-deposited state, the microstructures are composed of fine basket-weave regions, coarse basket-weave regions and ultrafine alpha Widmanstatten lath regions. The surface roughness of coarse basket-weave regions is much smaller than that of fine basket-weave regions and ultrafine alpha Widmanstatten lath regions. The alpha-phase distribution in fine basket-weave regions is more uniform than that in the coarse basket-weave regions. Its ultimate tensile strength of 971-1005 MPa, yield strength of 891-921 MPa and elongation of 4.5%-6.6% are close to those of Ti-6Al-4V alloy, and particularly, its specific strength of 224-232 kN center dot m/kg is better than that of Ti-6Al-4V alloy.
10.1016-S1003-6326(06)60263-X	11	glass; bulk; metallic; bulk metallic; gfa; bmg; glassy; metallic glass; ability; bulk metallic glass; amorphous; addition; crystallization; mm; glass-forming	Cu47Ti34Zr11Ni8, (Cu47Ti34Zr11Ni8)(99)Si and (Cu47Ti34Zr11Ni8)(99)Al bulk metallic glass were prepared by copper mold casting method, and the thermal stability, mechanical properties and microstructures of them were studied. With minor alloying of Si and Al additions, the glass transition temperature (T-g), crystallization temperature (T-x1) and temperature interval of supercooled liquid region Delta T-x (=T-x1-T-g) and reduced glass transition temperature (T-rg) were proved to be changed from 672 K, 734 K, 62 K, 0.575 to 691 K, 752 K, 61 K, 0.592 and to 681 K, 729 K, 48 K, 0.590, respectively. The results indicate that the glass-forming ability (GFA) are improved with minor alloying additions. And the bulk glasses also exhibits high three point-bending flexural strength . Because of the additions of Si and Al, three point-bending flexural strength and flexural modulus of the bulk glass change from 2 350 MPa, 102 GPa to 3 260 MPa, 102 GPa and 2 970 MPa, 108GPa respectively. The obvious strengthening is due to the appearance of the medium-range ordered regions with a size of 2-5 nm under the high-resolution TEM image. The reason that the mixed amorphous and nanocrystalline phases caused by minor alloying of Si and Al additions, is that Si or Al is the third kind of elements, which are different from other constituting elements, and there are a strong bonding and atoms size effects between constituting elements, which cause the glass-forming ability (GFA) and the bulk metallic glasses strength improving.
10.1016-S1003-6326(07)60041-7	11	glass; bulk; metallic; bulk metallic; gfa; bmg; glassy; metallic glass; ability; bulk metallic glass; amorphous; addition; crystallization; mm; glass-forming	Bulk amorphous CU52.5Ti30Zr11.5Ni6 and CU53.1Ti31.4Zr9.5Ni6 alloys with a high glass forming ability can be quenched into single amorphous rods with a diameter of 5 mm, and exhibit a high fracture strength of 2 212 MPa and 2 184 MPa under compressive condition, respectively. The stress-strain curves show nearly 2% elastic strain limit, yet display no appreciable macroscopic plastic deformation prior to the catastrophic fracture due to highly localized shear bands. The present work shows clearly evidence of molten droplets besides well-developed vein patterns typical of bulk metallic glasses on the fracture surface, suggesting that localized melting induced by adiabatic heating may occur during the final failure event.
10.1016-S1003-6326(08)60184-3	16	wear; composite; composites; powders; milling; particles; powder; wt; sliding; friction; hardness; matrix; mechanical; surface; properties	The influence of porosity on the wear behavior of high Volume fraction (61%) SiCP/Cu composite produced by pressureless infiltration was studied using a sliding, reciprocating and vibrating(SRV) machine. SiCp/Cu composites slid against hardened GCr15 bearing steel ball in the load range of 40-200 N. The results show that the wear rate increases with increasing porosity. The composite containing low porosity shows excellent wear resistance, which is attributed to the presence of mechanically mixed layer on the worn surface. In this case, the dominant wear mechanism is oxidative wear. Comparatively, the composite containing high porosity exhibits inferior wear resistance. Fracture and spalling of the particles are considered as the main causes of severe wear. Third body abrasion is the controlling wear mechanism. In addition, porosity has more important influence on wear rate at high load than at low load. This is associated with the fact that the fracture and spalling of particles is a process of crack initiation and propagation. At lower load, the pores beneath the worn surface can not propagate significantly, while the pores become unstable and easily propagate under high load, which results in a higher wear rate.
10.1016-S1003-6326(08)60390-8	-1		A small amount of misch metal was added to Cu-Zn-Al alloy in order to study its effect on grain refinement, mechanical properties, phase transformation behavior and stabilization of martensite. It is found that the addition of misch metal is very effective for reducing the grain size. The coarse grains over 1 000 mu m are refined to the size of 30 mu m by the addition of 0.43% (mass fraction) misch metal. The grain size of thermo-mechanically treated alloys is barely affected by cold working. The fracture strength and ductility increase significantly with the increase of misch metal content when tensile test is carried out below M(f) temperature. Also, the fracture strength is larger in the case of post-quench ageing treatment than that in the case of direct quench ageing treatment. The fracture mode is changed from transgranular brittle fracture to ductile fracture with void formation and coalescence by the addition of misch metal.
10.1016-S1003-6326(09)60078-9	-1		The crystallization kinetics of the bulk amorphous Cu58.1Zr35.9Al6 alloy was examined by differential scanning calorimetry under continuous heating and isothermal annealing. During continuous heating, the activation energy of crystallization was determined to be 383 kJ/mol by Kissinger method. However, on the isothermal annealing, the activation energy was determined to be 459.2 kJ/mol by the Arrhenius method, which was much larger than that obtained from the Kissinger method. The different temperatures at which crystallization occurs are responsible for the discrepancy in the activation energy. The average Avrami exponent of about 3.5 implies that the crystallization process of the bulk amorphous Cu58.1Zr35.9Al6 alloy is diffusion-controlled with a nucleation rate decreasing with time.
10.1016-S1003-6326(10)60122-7	13	clusters; atomic; glass; atoms; composition; dynamics; metallic; icosahedral; glasses; simulations; molecular; cu-zr; molecular dynamics; metallic glasses; structural	From the point of translation from liquid to amorphous phase, a new approach for composition design of bulk metallic glasses (BMGs) was suggested based on the stability estimations of liquid and amorphous phases. Gibbs free energy (Delta G) of liquid phase, which can be calculated approximately using mixing enthalpy (Delta H-mix) and configuration entropy (S-config) was taken as a stability criterion of liquid phase. On the other hand, vacancy formation energy (Delta H-h) was used to evaluate the stability of amorphous phase due to the linear relationship between Delta H-h and crystallization temperature (T-x). Based on these two sides, new Cu-Zr-Nd bulk metallic glasses were designed and synthesized successfully by suction-casting into copper mold. Experimental results about glass-forming ability are consistent with the computational values, which not only proves the validity of the new approach for composition design but also shows the new BMG of Cu60.5Zr34Nd5.5 can be cast into amorphous alloys with 2 mm in diameter.
10.1016-S1003-6326(11)61250-8	6	grain; deformation; strain; strength; dislocation; cu-; tensile; size; ecap; grain size; sfe; ductility; hardening; high; stress	Cu, Cu-2.2%Al and Cu-4.5%Al with stacking fault energies (SFE) of 78, 35 and 7 mJ/m(2) respectively were processed by cold-rolling (CR) at liquid nitrogen temperature (77 K) after hot-rolling. X-ray diffraction measurements indicate that a decrease in SFE leads to a decrease in crystallite size but increase in microstrain, dislocation and twin densities of the CR processed samples. Tensile tests at room temperature indicate that as the stacking fault energy decreases, the strength and ductility increase. The results indicate that decreasing stacking fault energy is an optimum method to improve the ductility without loss of strength .
10.1016-S1003-6326(11)61253-3	-1		The growth kinetics of intermetallic compound layer between molten In-Sn alloy and Cu40Zr44Al8Ag8 bulk metallic glass substrate was examined by solid state isothermal aging at the temperature range between 333 and 393 K. The aged samples were characterized by scanning electron microscopy and energy dispersive spectrometry. It is found that the intermetallic compound layer is composed of Zr, Cu and Sn. The layer growth of the intermetallic compound is mainly controlled by a diffusion mechanism over the temperature range and the value of the time exponent is approximately 0.5. The apparent activation energy for the growth of total intermetallic compound layers is 98.35 kJ/mol calculated by the Arrhenius equation.
10.1016-S1003-6326(11)61425-8	-1		Cu50Zr40Ti10 bulk amorphous alloys were fabricated by hot pressing gas-atomized Cu50Zr40Ti10 amorphous powder under different consolidation conditions without vacuum and inert gas protection. The consolidation conditions of the Cu50Zr40Ti10 amorphous powder were investigated based on an L-9(3(4)) orthogonal design. The compression strength and strain limit of the Cu50Zr40Ti10 bulk amorphous alloys can reach up to 1090.4 MPa and 11.9 %, respectively. The consolidation pressure significantly influences the strain limit and compression strength of the compact. But the mechanical properties are not significantly influenced by the consolidation temperature. In addition, the preforming pressure significantly influences not the compression strength but the strain limit. The optimum consolidation condition for the Cu50Zr40Ti10 amorphous powder is first precompacted under the pressure of 150 MPa, and then consolidated under the pressure of 450 MPa and the temperature of 380 degrees C.
10.1016-S1003-6326(13)62522-4	-1		Metastable liquid phase separation and rapid solidification in a metastable miscibility gap were investigated on the Cu60Co30Cr10 alloy by using the electromagnetic levitation and splat-quenching. It is found that the alloy generally has a microstructure consisting of a (Co,Cr)-rich phase embedded in a Cu-rich matrix, and the morphology and size of the (Co,Cr)-rich phase vary drastically with cooling rate. During the electromagnetic levitation solidification processing the cooling rate is lower, resulting in an obvious coalescence tendency of the (Co,Cr)-rich spheroids. The (Co,Cr)-rich phase shows dendrites and coarse spheroids at lower cooling rates. In the splat quenched samples the (Co,Cr)-rich phase spheres were refined significantly and no dendrites were observed. This is probably due to the higher cooling rate, undercooling and interface tension.
10.1016-S1003-6326(13)62602-3	15	aging; strength; conductivity; electrical conductivity; electrical; mpa; treatment; strengthening; degrees; cu-; cold; precipitation; tensile strength; tensile; iacs	The vacuum medium-frequency induction melting technology was employed to prepare the Cu-15%Cr-0.24%Zr alloy. The scanning electron microscopy (SEM), energy dispersive spectroscopy (EDS), transmission electron microscopy (TEM) and high-resolution transmission electron microscopy (BRTEM) were used to analyze the phase composition, morphology and structure of the alloy. The results reveal that the as-cast structure of the alloy consists of Cu matrix, Cr dendrite, eutectic Cr and Zr-rich phase. A large number of Cr-precipitated phases occur in the Cu matrix, and Cu5Zr particles can be found in the grain boundary of Cu matrix. The HRTEM images prove that there is a semi-coherent relationship between Cu5Zr and Cu matrix.
10.1016-S1003-6326(13)62670-9	2	corrosion; surface; film; electrochemical; films; spectroscopy; layer; current; solution; potential; resistance; composition; x-ray; ions; showed	Electrochemical noise (EN) data were measured during the dissolution and passivation of an Cu-Pb anode at 65 degrees C in 1 L industrial electrolyte containing 2 mg of gelatine and 4 mg of thiourea. The EN data corresponding to three stages or regions of active, pre-passive and passive on chronopotentiogram curve were analyzed by wavelet transform technique. The results reveal the pitting type of localized corrosion form during both active and pre-passive stages under a constant current density of 215 mA/cm(2). During the passive stage, a general corrosion form accompanied by oxygen evolution was observed.
10.1016-S1003-6326(13)62693-X	11	glass; bulk; metallic; bulk metallic; gfa; bmg; glassy; metallic glass; ability; bulk metallic glass; amorphous; addition; crystallization; mm; glass-forming	Mechanical properties of (Cu50Zr43Al7)(100-x)Nb-x (x=0,1,3,6,9) bulk metallic glasses rods with a diameter of 2.5 mm prepared by suction casting method were studied. The results of uniaxial compression tests at room temperture show that the best mechanical properties of 2.8% and 1.98 GPa for plastic strain and fracture strength, respectively, in the sample with x=3. Microstructure, fracture surface and shear bands of the samples were observed by SEM and XRD methods.
10.1016-S1003-6326(14)63097-1	2	corrosion; surface; film; electrochemical; films; spectroscopy; layer; current; solution; potential; resistance; composition; x-ray; ions; showed	The corrosion behaviors of copper and copper/titanium galvanic couple (GC) in seawater were studied by electrochemical impedance spectroscopy (EIS) and electrochemical noise (EN) techniques in conjunction with scanning electron microscopy (SEM) method. The results show that the corrosion process of copper in seawater can be divided into two stages, in which corrosion resistance and S, show the same evolution trend of initial increase and subsequent decrease, while S-G changes oppositely. However, the ensemble corrosion process of copper/titanium GC in seawater includes three stages, in which corrosion resistance and S-E show the evolution features of initial decrease with a subsequently increase, and the final decrease again; while S-G changes oppositely. The potential difference between copper and titanium in their galvanic couple can accelerate the initiation of pitting corrosion of copper, and both the minimum and maximum corrosion potentials of copper/titanium GC are much more positive than those of pure copper.
10.1016-S1003-6326(14)63566-4	-1		The observations of grain-boundary segregation of Bi in Cu bicrystals were analyzed. According to equilibrium grain boundary segregation (EGS) model and non-equilibrium grain-boundary segregation (NGS) model, respectively, the segregation kinetics of isothermal annealing at 500 degrees C and that of isochronal annealing for 24 h of Bi in Cu bicrystals were investigated. By qualitative analysis and quantitative analysis, it is concluded that the grain-boundary segregation of Bi agrees well with the theory of NGS. Based on the kinetics model of NGS, some parameters that are useful to predicting and controlling the Bi-induced embrittlement in Cu alloys are calculated as follows: the diffusion coefficient of Bi-vacancy complexes D-c=7.8x10(-5)exp[-1.46/(kT)]; the apparent diffusion coefficient of Bi atoms D-A(i)= 7.66x10(at+b)exp[-1.76/(kT)], where a=8.45x10(-8) and b=-13.37.
10.1016-S1003-6326(15)63583-X	16	wear; composite; composites; powders; milling; particles; powder; wt; sliding; friction; hardness; matrix; mechanical; surface; properties	An attempt was made to synthesize Cu/B4C surface composite using friction stir processing (FSP) and to analyze the influence of tool rotational speed on microstructure and sliding wear behavior of the composite. The tool rotational speed was varied from 800 to 1200 r/min in step of 200 r/min. The traverse speed, axial force, groove width and tool pin profile were kept constant. Optical microscopy and scanning electron microscopy were used to study the microstructure of the fabricated surface composites. The sliding wear behavior was evaluated using a pin-on-disc apparatus. The results indicate that the tool rotational speed significantly influences the area of the surface composite and the distribution of B4C particles. Higher rotational speed exhibits homogenous distribution of B4C particles, while lower rotational speed causes poor distribution of B4C particles in the surface composite. The effects of tool rotational speed on the grain size, microhardness, wear rate, worn surface and wear debris were reported.
10.1016-S1003-6326(15)63622-6	-1		The microstructure and its effects on the high temperature mechanical behavior of Cu-2.7%Al2O3 (volume fraction) dispersion strengthened copper (ADSC) alloy were investigated. The results indicate that fine alumina particles are uniformly distributed in the copper matrix, while a few coarse ones are distributed on the grain boundaries. Tensile tests results show that Hall-Petch mechanism is the main contribution to the yield strength of ADSC alloy at room temperature. Its high temperature strength is attributed to the strong pinning effects of alumina particles on the grain and sub-grain boundaries with dislocations. The ultimate tensile strength can reach 237 MPa and the corresponding yield strength reaches 226 MPa at 700 degrees C. Tensile fracture morphology indicates that the ADSC alloy shows brittleness at elevated temperatures. Creep tests results demonstrate that the steady state creep rates at 400 degrees C are lower than those at 700 degrees C. The stress exponents at 400 degrees C and 700 degrees C are 7 and 5, respectively, and the creep strain rates of the ADSC alloy are controlled by dislocation core diffusion and lattice diffusion.
10.1016-S1003-6326(15)63675-5	-1		Cu-15% NbC (volume fraction) powder was synthesized using the starting powders of Cu, Nb and graphite in a high energy vibratory disc mill for 7 h of milling under argon atmosphere. A composite sample and a Cu/NbC functionally graded material (FGM) sample were produced by using the two-step press and sintering at 900 degrees C for 1 h under vacuum. The microstructure and physical and mechanical properties of the specimens were investigated. The field emission scanning electron microscopy, energy dispersive X-ray and X-ray diffraction analysis confirmed the synthesis of the nanostructure matrix of 18-27 nm with the nanoparticles reinforcement of 42 nm after sintering, verifying the thermal stability of this composite at high temperature. The hardness of Cu-15% NbC was five times greater than that of the pure Cu specimen. The volume reduction of the sample after the wear test decreased in comparison with the pure Cu specimen. The electrical conductivity of the composite specimen decreased to 36.68% IACS. The FGM specimen exhibited high electrical conductivity corresponding to 75.83% IACS with the same hardness and wear properties as those of the composite sample on the composite surface. Thus, Cu/NbC FGM with good mechanical and electrical properties can be a good candidate for electrical contact applications.
10.1016-S1003-6326(15)63716-5	-1		The evolution of nanoporous structure with dealloying condition was investigated, thus, the mechanism of porous structure evolution was uncovered. The Gasar Cu-Mn alloy was dealloyed by room and elevated temperature chemical corrosion, low and high current level electrochemical corrosion, four types of porous structures, including uneven corrosion pits, hybrid porous, haystack type and bicontinuous model were prepared by chemically and electrochemically dealloying the porous Cu-34.6% Mn alloy made by the Gasar process. Then, the surface diffusion coefficient (D-S) and the diffusion frequency (k(D)) of Cu atom, as well as the dissolution frequency (k(E)) of Mn atom were calculated with dealloying condition. The dealloyed morphologies for room temperature chemical corrosion and low current level electrochemical corrosion were similar due to the same D-S. While the dealloyed structures changed from bulk hybrid porous structure to bicontinuous porous film with decreasing k(D)/k(E).
10.1016-S1003-6326(15)63717-7	15	aging; strength; conductivity; electrical conductivity; electrical; mpa; treatment; strengthening; degrees; cu-; cold; precipitation; tensile strength; tensile; iacs	Cu-0.81Cr-0.12Zr-0.05La-0.05Y (mass fraction) alloy was successively subjected to hot rolling, solid solution treatment, cold rolling and aging treatments. Its microstructure, microhardness and electrical conductivity at different states were systematically investigated. The as-cast microstructure consists of three phases: Cu matrix, Cr and Cu5Zr. Zr is completely dissolved into the matrix while partial Cr remains after the solid solution treatment. Aging of the cold-rolled sample makes nanocrystals of Cr and Cu5Zr precipitate from the matrix, and the microhardness and electrical conductivity rise. A combination of high microhardness (HV 186) and high conductivity (81% IACS) can be obtained by aging the sample at 773 K for 60 min. As the aging temperature increases, the orientation degree of the Cu crystals gradually decreases to zero, but the microstrain in them cannot be eliminated completely owing to the presence of precipitates and dislocations. The Cr precipitates exhibit the N-W orientation relationship with the matrix when the coherence strengthening mechanism plays a main role.
10.1016-S1003-6326(15)63807-9	17	wear; composites; coating; friction; composite; coatings; surface; tribological; properties; wear resistance; resistance; powder; sliding; matrix; wear rate	Four kinds of Cu-based composites with different mass ratios of graphite and WS2 as lubricants were fabricated by hot-pressing method. Electrical sliding wear behaviors of the composites were investigated using a block-on-ring tribometer rubbing against Cu-5% Ag alloy ring. The results demonstrated that 800 degrees C was the optimum sintering temperature for Cu-graphite-WS2 dual-lubricant composites to obtain the best comprehensive properties of mechanical strength and lubrication performance. Contact voltage drops of the Cu-based composites increased with increasing the mass ratio of WS2 to graphite. The Cu-based composite with 20% graphite and 10% WS2 showed the best wear resistance due to the excellent synergetic lubricating effect of graphite and WS2. The reasonable addition of WS2 into the Cu-graphite composite can remarkably improve the wear resistance without much rise of electrical energy loss which provides a novel principle of designing suitable sliding electrical contact materials for industrial applications.
10.1016-S1003-6326(15)63844-4	16	wear; composite; composites; powders; milling; particles; powder; wt; sliding; friction; hardness; matrix; mechanical; surface; properties	In order to study the wear behavior of different kinds of contact wires, the dry sliding wear behaviors of Cu-Sn, Cu-Ag and Cu-Mg alloys prepared by up-drawn continuous casting and followed continuous extrusion were studied. The research was tested on a block-on-ring wear tester. The results indicate that the friction coefficient is remarkably influenced by the formation of a continuous tribofilm, which consists of oxidation film. The abrasion, adhesion, oxidation and plastic deformation are observed. Oxidation and abrasion wear mechanisms dominate at the lower sliding velocity and load. The combination of oxidation and adhesion play leading roles with the increasing load and velocity. Plastic deformation is detected under higher applied load and sliding velocities.
10.1016-S1003-6326(15)63921-8	6	grain; deformation; strain; strength; dislocation; cu-; tensile; size; ecap; grain size; sfe; ductility; hardening; high; stress	The texture evolution and mechanical properties of Cu-Ag alloys subjected to severe plastic deformation at cryogenic temperature (CT) were investigated and the sequent annealing behaviors were also studied. Compared with the sheets rolled at room temperature (RT) showing copper texture, the CT-rolled sheets exhibited brass texture which indicated that cross-slip was suppressed at CT, and both the ultimate tensile strength and yield strength of the sheets were increased. Due to the in-situ recrystallization mechanism, recrystallization textures in as-annealed CT-rolled sheets were randomly distributed, while the as-annealed RT-rolled sheets mainly contained cube texture. Microstructures of the rolled and annealed sheets were observed using optical microscopy and electronic back-scatter diffraction. The results show that the dynamic recovery was suppressed during CT-rolling and resulted in higher deformation energy storage. Therefore, the recrystallization of CT-rolled sheets could start at a lower temperature than that of RT-rolled sheet at the same reduction.
10.1016-S1003-6326(15)63926-7	-1		A new kind of laminar metal matrix nanocomposite (MMC) was fabricated by an electrodeposition process with copper and superaligned carbon nanotubes film (SACNT film). The SACNT film was put on a titanium plate and then a layer of copper was electrodeposited on it. By repeating the above process, the laminar Cu/SACNT composite which contains dozens or hundreds of layers of copper and SACNT films was obtained. The thickness of a single copper layer was controlled by adjusting the process parameter easily and the thinnest layer is less than 2 mu m. The microscopic observation shows that the directional alignment structure of SACNT is retained in the composite perfectly. The mechanical and electrical properties testing results show that the tensile and yield strengths of composites are improved obviously compared with those of pure copper, and the high conductivity is retained. This technology is a potential method to make applicable MMC which characterizes high volume fraction and directional alignment of carbon nanotubes.
10.1016-S1003-6326(15)63960-7	-1		The microstructure evolution and phase transformation of Cu-20Ni-20Mn (mass fraction, %) alloy at 450 degrees C were investigated by X-ray diffraction and transmission electron microscopy (TEM). The variations of tensile strength, yield strength and hardness of this alloy during aging process were also analyzed. The results show that no significant variations of hardness and strength in the initial stage of aging, with a long incubation period, are observed at 450 degrees C. Subsequently, the ordered face-centered tetragonal (FCT) NiMn phase nucleates and grows up with prolonging the aging time. The hardness and tensile strength of the alloy increase up to their maximum values with increasing the ordered particle size, i.e., the strength of the alloy reaches 942 MPa after being aged at 450 degrees C for 40 h . The main cause of the age-hardening is considered to be precipitation strengthening due to the ordered FCT-NiMn particles.
10.1016-S1003-6326(16)64239-5	16	wear; composite; composites; powders; milling; particles; powder; wt; sliding; friction; hardness; matrix; mechanical; surface; properties	Production of Cu-Cr/carbon nanotube (CNT) hybrid nano-composite by wet and dry milling processes at three different levels of milling energy was investigated in order to study the effect of milling energy in two different media on dispersion of CNTs, and preparation of the nano-composite. The structural evolution and solid solution formation were evaluated by X-ray diffraction technique. The microstructure was characterized by scanning electron microscopy and transmission electron microscopy. Also, the mechanical properties were measured by microhardness test. The mean crystallite size was in the range of 20-63 nm depending on milling medium and energy. CNTs dispersion is a function of milling energy. According to FESEM images and microhardness results, it can be concluded that wet milling is more applicable in dispersing CNTs homogeneously in comparison to dry milling. It was also found that wet milling at higher milling energies can be a beneficial method of producing the homogeneous hybrid nano-composite with the least damages introducing on CNTs because of the higher microhardness which can be attributed to better dispersion of less damaged CNTs. Compared with crystallite size changes, CNTs dispersion and damages were considerably more effective on hardness.
10.1016-S1003-6326(16)64285-1	-1		Creep and anelastic backflow behaviors of pure copper (4N Cu) with grain size d(g) = 40 mu m were investigated at low temperatures of T <0.3T(m) (T-m is melting point) and ultra-low creep rates of epsilon <= 1x10(-10) s(-1) by a high strain-resolution measurement (the helicoid spring specimen technique). Analysis of creep data was based on the scaling factors of creep curves instead of the conventional extrapolated steady-state creep rate. Power-law creep equation is suggested to be the best for describing the primary transient creep behavior, because the pre-parameter does not apparently change with elapsed time. The observed anelastic strains are 1/6 of the calculated elastic strains, and linear viscous behavior was identified from the logarithm plot of the anelastic strain rate versus anelastic strain (slope equals 1). Therefore, the creep anelasticity is suggested to be due to the unbowing of there-dimensional network of dislocations.
10.1016-S1003-6326(16)64452-7	-1		To select the proper composition and obtain an overall material-microstructure-property relationship for Cu-Fe alloy, the effect of Fe content on microstructure and properties of Cu-Fe-based composite coatings by laser induction hybrid rapid cladding was investigated. Microstructure characterization of the composite coatings was tested utilizing SEM, XRD and EDS. Microhardness measurement was executed to evaluate the mechanical properties of the composite coatings. The results show that for low Fe content, the composite coating presents a feature that Fe-rich equiaxed dendrites are embedded in the Cu-rich matrix. With increasing Fe content, the Fe-rich particles are dispersed in the Cu-rich matrix. With further increasing Fe content, large amounts of Cu-rich particles are homogeneously dispersed in the interdendrite of the Fe-rich matrix. Correspondingly, the average microhardness of the composite coatings increases gradually with the increase of Fe content and the microhardness of Cu14.5Fe83Si2C0.5 coating is much twice higher than that of the substrate.
10.1016-S1003-6326(17)60011-6	-1		Cu with and without La addition was prepared and the effect of a trace amount of La on the arc erosion behaviors and oxidation resistance of Cu alloys was investigated. The results indicate that CuLa alloy exhibits superior oxidation resistance and arc erosion resistance. The contact resistance and temperature rise were obviously improved. The oxidation resistance of CuLa alloy mainly is due to the interface wrapping of La2O3 particles and CuLa alloy phase on Cu atoms. Thermodynamic calculation indicated that La2O3 could form preferentially in the CuLa alloy, which was beneficial for the protection of the Cu substrate. According to kinetics analysis, the activation energy of CuLa alloy was higher than that of pure Cu, indicating the better oxidation resistance of CuLa alloys.
10.1016-S1003-6326(17)60026-8	0	solidification; phase; magnetic; magnetic field; undercooling; field; liquid; separation; peritectic; immiscible; cu-; dendrite; phase separation; microstructure; primary	Rapid solidification of Cu-Co immiscible alloy was investigated by glass-fluxing, spray casting and melt-spinning techniques. Both the transition from dendrite to dispersive structure and corresponding scale evolution were revealed and further elucidated in terms of the heat flow mode, nucleation and growth processes under different solidification conditions. With the increase of undercooling, columnar dendrite is replaced by dispersive structure due to the immiscible effect. In contrast, equiaxed dendrite forms in spray cast alloy due to multiple nucleation events and becomes thinner for the case of higher cooling rate. Ascribed to the enhanced non-equilibrium effect and insufficient period for collision and coagulation processes between separated droplets, fine globular dispersion appears upon the diameter of spray casting reaching 4 mm. As for the melt-spun ribbon with the highest cooling rate, a single-phase solid solution microstructure with refined grain of cellular morphology can be obtained, which is attributed to the suppression of liquid phase separation by instant solidification.
10.1016-S1003-6326(17)60040-2	11	glass; bulk; metallic; bulk metallic; gfa; bmg; glassy; metallic glass; ability; bulk metallic glass; amorphous; addition; crystallization; mm; glass-forming	In-situ formed (Cu0.6Zr0.3Ti0.1)(95)Nb-5 bulk metallic glass (BMG) composite with Nb-rich dendrite randomly dispersed in hard glassy matrix was prepared by casting into a water-cooled copper mold. The dendrite has much smaller hardness and elastic modulus than glassy matrix, and the stress concentration at interface provides a channel for the initiating and branching of shear bands upon loading, thus leading to a high compressive fracture strain of 6.08% and fracture strength about 2200 MPa. Comparing with other Cu-based BMG composite, the fracture strength of present (Cu0.6Zr0.3Ti0.1)(95)Nb-5 composite is not significantly reduced, indicating that the addition of Nb in the current work is an effective and effortless way to fabricate new practical BMG composites with enhanced strength and good plasticity.
10.1016-S1003-6326(17)60070-0	16	wear; composite; composites; powders; milling; particles; powder; wt; sliding; friction; hardness; matrix; mechanical; surface; properties	The wear behavior of multi-walled carbon nano-tubes (MWCNTs) reinforced copper metal matrix composites (MMCs) processed through powder metallurgy (PM) route was focused on and further investigated for varying MWCNT quantity via experimental, statistical and artificial neural network (ANN) techniques. Microhardness increases with increment in MWCNT quantity. Wear loss against varying load and sliding distance was analyzed as per L16 orthogonal array using a pin-on-disc tribometer. Process parameter optimization by Taguchi's method revealed that wear loss was affected to a greater extent by the introduction of MWCNT; this wear resistant property of newer composite was further analyzed and confirmed through analysis of variance (ANOVA). MWCNT content (76.48%) is the most influencing factor on wear loss followed by applied load (12.18%) and sliding distance (9.91%). ANN model simulations for varying hidden nodes were tried out and the model yielding lower MAE value with 3-7-1 network topology is identified to be reliable. ANN model predictions with R value of 99.5% which highly correlated with the outcomes of ANOVA were successfully employed to investigate individual parameter's effect on wear loss of Cu-MWCNT MMCs.
10.1016-S1003-6326(17)60128-6	15	aging; strength; conductivity; electrical conductivity; electrical; mpa; treatment; strengthening; degrees; cu-; cold; precipitation; tensile strength; tensile; iacs	A novel Cu-6.5Ni-1Al-1Si-0.15Mg-0.15Ce alloy with super-high strength was designed and its corrosion behavior in 3.5% NaCl solution at 25 degrees C was investigated by the means of SEM observation, TEM observation and XPS analysis. The alloy after solution treatment, 80% cold rolling and aging at 450 degrees C for 1 h had the best comprehensive properties with hardness of HV 314, electrical conductivity of 19.4% IACS, tensile strength of 1017 MPa, and average annual corrosion rate of 0.028 mm/a. The oxides and chloride products formed at first, followed by the formation of dyroxides products. The alloy showed super-high strength, good electrical conductivity and corrosion resistant because Ni2Si hindered the precipitation of large NiAl at the grain boundary and the denickelefication of the alloy.
10.1016-S1003-6326(17)60219-X	-1		Cu-15Ni-8Sn-0.3Nb alloy rods were prepared by means of powder metallurgy followed by hot extrusion. Element maps obtained by electron probe micro analyzer (EPMA) showed that Nb-rich phases were formed and distributed within grains and at grain boundaries of the Cu-15Ni-8Sn-0.3Nb alloy. Transmission electron microscope (TEM) results indicated that there was no obvious orientation relationship between these phases and the matrix. Spinodal decomposition and ordering transformation appeared at early stages of aging at 400 degrees C and caused significant strengthening. Cu-15Ni-8Sn-0.3Nb alloy exhibited both higher strength (ultimate tensile strength > 1030 MPa) and higher tensile ductility (elongation>9.1%) than Cu-15Ni-8Sn alloy after aging treatment. The improvement was caused by Nb-rich phases at grain boundaries which led o the refinement of grain size and postponed the growth of discontinuous precipitates during aging.
10.1016-S1003-6326(18)64699-0	2	corrosion; surface; film; electrochemical; films; spectroscopy; layer; current; solution; potential; resistance; composition; x-ray; ions; showed	The corrosion behavior of the Cu-Ti alloys with different Ti contents in 3.5% (mass fraction) NaCl solution was investigated using electrochemical measurements, immersion tests, mass loss measurements and SEM observation. The results show that Ti dissolved in the Cu matrix changes the corrosion process of the alloys. Pure Cu sample exhibits a typical active-passive-transpassive corrosion behavior. The anodic polarization current densities of the Cu-Ti alloys steadily increase with increasing applied potential, indicating that active dissolution of copper proceeds due to the potential difference in the galvanic coupling of Cu and Ti. The increase of Ti content decreases the corrosion resistance of the Cu-Ti alloys.
10.1016-S1003-6326(18)64729-6	16	wear; composite; composites; powders; milling; particles; powder; wt; sliding; friction; hardness; matrix; mechanical; surface; properties	The effects of MoS2 content on microstructure, density, hardness and wear resistance of pure copper were studied. Copper-based composites containing 0-10% (mass fraction) MoS2 particles were fabricated by mechanical milling and hot pressing from pure copper and MoS2 powders. Wear resistance was evaluated in dry sliding condition using a pin on disk configuration at a constant sliding speed of 0.2 m/s. Hardness measurements showed a critical MoS2 content of 2.5% at which a hardness peak was attained. Regardless of the applied normal load, the lowest coefficient of friction and wear loss were attained for Cu/2.5MoS(2) composite. While coefficient of friction decreased when the applied normal load was raised from 1 to 4 N at any reinforcement content, the wear volume increased with increasing normal load. SEM micrographs from the worn surfaces and debris revealed that the wear mechanism was changed from mainly adhesion in pure copper to a combination of abrasion and delamination in Cu/MoS2 composites.
10.1016-S1003-6326(18)64752-1	2	corrosion; surface; film; electrochemical; films; spectroscopy; layer; current; solution; potential; resistance; composition; x-ray; ions; showed	The effect of heat treatment on corrosion properties of CuAlNi shape memory alloy was investigated in 0.9% NaCl solution at pH 7.4 and 37 degrees C by open circuit potential measurements, polarisation techniques, and electrochemical impedance spectroscopy. Investigations were performed on CuAlNi alloy samples in as-cast state and after heat treatment procedure containing annealing at 850, 885 and 920 degrees C followed by water quenching. Electrochemical impedance measurement results indicate that heat treatment of CuAlNi alloy leads to the increase in charge transfer resistance and surface layer resistance and the decrease in values of capacitance of the double and surface layers, indicating higher corrosion resistance compared with the as-cast CuAlNi alloy. The increase in polarisation resistance and the decrease in corrosion current density of heat-treated CuAlNi alloy also suggest beneficial influence of heat treatment on corrosion resistance of CuAlNi alloy. Optical microscopy, SEM/EDX and XRD analysis of samples surface after polarisation measurements show the occurrence of pitting corrosion on the electrode surfaces, with the existence of CuCl2, AlCl3 and Cu2Cl(OH)(3) compounds as the surface corrosion products.
10.1016-S1003-6326(18)64755-7	17	wear; composites; coating; friction; composite; coatings; surface; tribological; properties; wear resistance; resistance; powder; sliding; matrix; wear rate	The mechanical properties and tribological behaviors of Cu-WS2 composites fabricated by spark plasma sintering (SPS) using two different WS2 particle sizes of 0.6 and 5.0 mu m and Cu powders as raw materials were investigated. The results indicate that the bending strength and tribological behavior of Cu-WS2 composites are greatly affected by the size of WS2 particles. The bending strength of Cu-WS2 composites with the WS2 particle size of 5.0 mu m is 292.2 MPa. As the size of WS2 particle decreases to 0.6 mu m, the bending strength also decreases to 181.5 MPa. Moreover, as the WS2 particle size decreases from 5.0 to 0.6 mu m, the wear rate of Cu-WS2 composite sharply increases from 2.99x10(-14) to 6.13x10(-14) m(3)/(N.m) and its friction coefficient increases from 0.158 to 0.172. The size of WS2 particle (5.0 mu m) plays an important role in forming transfer film formed on the counter-face. The sample with 5.0 mu m WS2 particle forms smoother and more continuous transfer film, which results in a low wear rate and friction coefficient of the Cu-WS2 composites.
10.1016-S1003-6326(18)64848-4	16	wear; composite; composites; powders; milling; particles; powder; wt; sliding; friction; hardness; matrix; mechanical; surface; properties	Cu-1%Cr (mass fraction) and Cu-1%Cr-5% carbon nanotube (CNT) (mass fraction) nanocomposite powders were produced by mechanical alloying and consolidated by hot pressing. Then, nanocomposites were hot-rolled by the order of 50% reduction at 650 degrees C. The structure and microstructure were investigated by X-ray diffractometry (XRD) and scanning electron microscopy (SEM). Relative density, microhardness, thermal stability, electrical and wear properties were evaluated. Compared to the Cu-Cr sample, the relative density of Cu-Cr-CNT sample is greatly improved from 75% to near full density of 98% by hot rolling. Although electrical conductivity and microhardness increase in both Cu-Cr and Cu-Cr-CNT nanocomposites after hot rolling, the effect of hot rolling on the enhancement is more prominent in the presence of CNTs. The microhardness and electrical conductivity of hot-rolled Cu-Cr-CNT nanocomposite approach HV 175 and 68% (IACS), respectively. Also, hot rolling is more effective on thermal stability improvement of Cu-Cr-CNT nanocomposite compared to Cu-Cr composite. However, after hot rolling, both the friction coefficient and wear loss of the Cu-Cr sample display higher reduction than those of Cu-Cr-CNT nanocomposite owing to different wear mechanisms. After hot rolling, friction coefficient and wear loss of Cu-Cr sample display variation of 25% and 62%, respectively.
10.1016-S1003-6326(19)64986-1	8	hot; deformation; strain; strain rate; dynamic; hot deformation; recrystallization; dynamic recrystallization; flow; rate; flow stress; compression; constitutive; degrees; stress	The hot compressive deformation behaviors of Cu-6wt% Ag alloy were studied experimentally in the temperature range of 973-1123 K and the strain rate range of 0.01-10 s(-1). The stress increases and reaches the maximum value when the true strain is very small, and then the stress changes slowly and tends to be stable under the action of work hardening, dynamic recovery and recrystallization. The material parameters of the conventional Arrhenius constitutive model are only related to strain under different deformation conditions, and the prediction error is large, which cannot accurately characterize the hot deformation behavior of the alloy. To describe the hot deformation behavior of the alloy accurately, a modified constitutive model was established by considering the simultaneous influence of forming temperature, strain rate and strain. The results indicate that correlation coefficient (R) and the average absolute relative error (AARE) are 0.993 and 4.2%, respectively. The modified constitutive model can accurately describe the hot deformation behavior of Cu-6wt% Ag alloy.
10.1016-S1003-6326(19)65034-X	-1		Production of copper powders by the potentiostatic electrolysis under different hydrogen evolution conditions was investigated. Copper powders were characterized by the scanning electron microscope (SEM), X-ray diffraction (XRD), particle size distribution (PSD), and by the determination of the specific surface area (SSA) of the formed powders. Depending on quantity of hydrogen generated during electrolysis, the two types of particles were formed: dendrites and cauliflower-like particles. The dendrites were formed without, while cauliflower-like particles with the quantity of evolved hydrogen enough to achieve strong effect on hydrodynamic conditions in the near-electrode layer. Although macro structure of the particles was very different, they showed similar micro structure. Namely, both types of the particles consisted of small agglomerates of approximately spherical Cu grains at the micro level. The existence of the spherical morphology was just responsible for random orientation of Cu crystallites in both types of particles. The SSA of cauliflower-like particles was more than two times larger than that of the dendrites, while their size was considerably smaller than that of the dendritic particles. In this way, the useful benefit of Cu powder formation in the conditions of vigorous hydrogen evolution is shown.
10.1016-S1003-6326(19)65139-3	17	wear; composites; coating; friction; composite; coatings; surface; tribological; properties; wear resistance; resistance; powder; sliding; matrix; wear rate	The Al0.3CoCrFeNi high-entropy alloy (HEA) particles reinforced Cu matrix composites (CMCs) were fabricated by mechanical alloying and sintering. Transition layer structure was obtained by multi-step ball milling to investigate the related influence on element diffusion behavior and wear properties of CMCs. The results indicate that a new Cu transition layer is generated, and the thickness is about 5 mu m. Cr element diffuses into the interface via the transition layer, which forms the complex oxide. Because of the structure of Cu transition layer, the diffusion rates of Ni, Co and Fe increase, especially the Ni element. The wear resistance of CMCs is improved by 30%, which is due to the improvement of interface bonding strength, compared with the CMCs without transition layer. This method is applicable to the development of advanced HEA reinforced metallic matrix composites.
10.1016-S1003-6326(19)65140-X	-1		The influence of pile-up on the nanoindentation measurements in Cu-2wt%Be samples with precipitates was carefully studied. The precipitates were formed by aging treatments for 1 h at different temperatures between 540 and 680 K. The load-depth curves were analyzed using the classical Oliver and Pharr method, and the obtained elastic modulus and hardness were compared with values estimated by other techniques. An important level of pile-up was found in samples with precipitates and differences in the load-depth curves were observed between the unaged and aged samples. A correction of the contact depth considering the pile-up proposed by Loubet was used for hardness estimation. For the determination of the elastic modulus, an approach based on the relation between the ratio of unloading work to indentation total work, with the ratio H/E-r (H is the hardness; E-r is the reduced modulus), was employed. A specific relation between both parameters was developed.
10.1016-S1003-6326(19)65163-0	8	hot; deformation; strain; strain rate; dynamic; hot deformation; recrystallization; dynamic recrystallization; flow; rate; flow stress; compression; constitutive; degrees; stress	Effect of Si and Ti on dynamic recrystallization (DRX) of Cu-15Ni-8Sn alloy was studied using hot compression tests over deformation temperature range of 750-950 degrees C and strain rate range of 0.001-10 s(-1). The results show that the dynamic recrystallization behavior during hot deformation is significantly affected by the trace elements of Si and Ti. The addition of Si and Ti promotes the formation of Ni16Si7Ti6 particles during hot deformation, which promotes the nucleation of dynamic recrystallization by accelerating the transition from low-angle boundaries (LABs) to high-angle boundaries (HABs). Ni16Si7Ti6 particles further inhibit the growth of recrystallized grains through the pinning effect. Based on the dynamic recrystallization behavior, a processing map of the alloy is built up to obtain the optimal processing parameters. Guided by the processing map, a hot-extruded Cu-15Ni-8Sn alloy with a fine-grained microstructure is obtained, which shows excellent elongation of 30% and ultimate tensile strength of 910 MPa.
10.1016-S1003-6326(20)65268-2	15	aging; strength; conductivity; electrical conductivity; electrical; mpa; treatment; strengthening; degrees; cu-; cold; precipitation; tensile strength; tensile; iacs	Cu-0.36wt%Be-0.46wt%Co alloy plate with 300 mm in width and 10 mm in thickness prepared by heating-cooling combined mold (HCCM) horizontal continuous casting was cold rolled. Microstructure evolution and mechanical properties of the alloy as well as its deformation mechanism were investigated. The results showed that the as-cast alloy plate had columnar grains along the length direction, good surface quality and elongation of 35%, which was directly large-reduction cold rolled without surface treatment, and the accumulative cold rolling reduction reached 98%. When the reduction was small (20%), numerous dislocations and dislocation cells formed, and the deformation mechanism was dislocation slip. When the reduction was 40%, deformation twins appeared, and interactions between twins and dislocation cells induced strip-like dislocation cells. When the reduction exceeded 60%, shear bands formed and apparent crystal rotation in the micro-region happened. Further increasing the reduction, the amount of the shear bands rose and they interacted with each other, which refined the grains apparently. The tensile strength and hardness increased from 353 MPa and HV 119 of the as-cast alloy to 625 MPa and HV 208 with 95% reduction, respectively, and the elongation reduced from 35% to 7.6%. A process of HCCM horizontal continuous casting-cold rolling can work as a novel compact method to fabricate Cu-Be alloy sheet.
10.1016-S1003-6326(20)65270-0	-1		To address the issues of reduced graphene oxide (RGO) dispersion in copper (Cu) matrix and interface bonding between RGO and Cu, an electrostatic adsorption method with interface transition phase design was employed to prepare the RGO/Cu based composites. Cu-Ti alloy powder was employed to improve the combination by forming carbides at the RGO-Cu interface. It was noted that the mechanical property of 0.3wt%RGO/Cu-Ti composite was increased by 60% compared with that of the matrix. Strengthening mechanism analysis suggested that the enhancement of the mechanical property was ascribed to the load transfer and second phase strengthening which were from the improved dispersion of RGO and the in-situ formed titanium carbide phase.
10.1016-S1003-6326(20)65393-6	15	aging; strength; conductivity; electrical conductivity; electrical; mpa; treatment; strengthening; degrees; cu-; cold; precipitation; tensile strength; tensile; iacs	Cu-0.5wt%Cr alloy with high strength and high conductivity was processed by cryorolling (CR) and room temperature rolling (RTR), respectively. The microstructure, mechanical property and electrical conductivity of Cu-0.5Cr alloy after CR/RTR and aging treatment were investigated. The results indicate that obvious dislocation entanglement can be observed in matrix of CR alloy. The Cr particles in the alloy after CR and aging treatment possess finer particle size and exhibit dispersive distribution. The peak hardness of CR alloy is HV 167.4, significantly higher than that of RTR alloy. The optimum mechanical property of CR alloy is obtained after aging at 450 degrees C for 120 min. The conductivity of CR Cu-0.5Cr alloy reaches 92.5% IACS after aging at 450 degrees C for 120 min, which is slightly higher than that of RTR alloy.
10.1016-S1003-6326(20)65394-8	17	wear; composites; coating; friction; composite; coatings; surface; tribological; properties; wear resistance; resistance; powder; sliding; matrix; wear rate	The (Cu-10Sn)-Ni-MoS2 composites, prepared by powder metallurgy, were studied for the effects of Ni-coated MoS2 on the microstructure, mechanical properties and lubricating properties. The mechanism of effects of Ni and MoS2 on the properties of composites was analyzed through a comparative experiment by adding Ni and MoS2 separately. The results show that the nickel wrapping around the MoS2 particles decreases the reaction rate of MoS2 with the copper matrix, and greatly improves the bonding of the matrix. The composites with 12 wt% Ni-coated MoS2 (C12) show the optimum performance including the mechanical properties and tribological behaviors. Under oil lubrication conditions, the friction coefficient is 0.0075 with a pressure of 8 MPa and a linear velocity of 0.25 m/s. The average dry friction coefficient, sliding against 40Cr steel disc, is measured to be 0.1769 when the linear velocity and pressure are 0.25 m/s and 4 MPa, respectively.
10.1016-S1003-6326(20)65416-4	8	hot; deformation; strain; strain rate; dynamic; hot deformation; recrystallization; dynamic recrystallization; flow; rate; flow stress; compression; constitutive; degrees; stress	The hot compression deformation behavior of Cu-3Ti-0.1Zr alloy with the ultra-high strength and good electrical conductivity was investigated on a Gleeble-3500 thermal-mechanical simulator at temperatures from 700 to 850 degrees C with the strain rates between 0.001 and 1 s(-1). The results show that work hardening, dynamic recovery and dynamic recrystallization occur in the alloy during hot deformation. The hot compression constitutive equation at a true strain of 0.8 is constructed and the apparent activation energy of hot compression deformation Q is about 319.56 kJ/mol. The theoretic flow stress calculated by the constructed constitutive equation is consistent with the experimental result, and the hot processing maps are established based on the dynamic material model. The optimal hot deformation temperature range is between 775 and 850 degrees C and the strain rate range is between 0.001 and 0.01 s(-1).
10.1016-S1003-6326(20)65464-4	3	sma; shape; shape memory; memory; smas; superelastic; bars; damping; cu-al-mn; mechanical; bending; applications; numerical; sma bars; material	This work aimed to investigate and critically analyze the differences in microstructural features and thermal stability of Cu-11.3Al-3.2Ni-3.0Mn-0.5Zr shape memory alloy processed by selective laser melting (SLM) and conventional powder metallurgy. PM specimens were produced by sintering 106-180 mu m pre-alloyed powders under an argon atmosphere at 1060 degrees C without secondary operations. SLM specimens were consolidated through melting 32-106 mu m pre-alloyed powders on a Cu-10Sn substrate. Mechanical properties were measured through Vickers hardness testing. Differential scanning calorimetry was conducted to assess the martensitic transformation temperatures. X-ray diffraction patterns were collected to identify the metallurgical phases. Optical and scanning electron microscopy was used to analyze the microstructural features. beta(1)' martensite was found, irrespective of the processing route, although coarser martensitic variants were present in PM-specimens. In conventional powder metallurgy samples, intergranular eutectoid constituents and stabilized austenite also formed at room temperature. PM-specimens showed similar average hardness values to the SLM-specimens, albeit with high standard deviation linked to the porosity. The specimens processed by SLM showed reversible martensitic transformation (T-0 =171 degrees C). PM-processed specimens did not show shape memory effects.
10.1016-S1003-6326(20)65490-5	15	aging; strength; conductivity; electrical conductivity; electrical; mpa; treatment; strengthening; degrees; cu-; cold; precipitation; tensile strength; tensile; iacs	The role of Cr in affecting the precipitates and the properties of aged Cu-Cr-P alloys was investigated and discussed. The results show that there are mainly three sizes of Cr phase in aged Cu-Cr-P alloys, among them, the nano-sized Cr phase plays an important role in the strength of Cu-Cr-P alloys. The strengthening effect of Cr phase (less than 5 nm) with FCC structure completely coherent with the matrix is calculated to be about 200 MPa on the basis of dislocation cut-through mechanism. The strengthening effect of Cr phase (10-20 nm) with BCC structure incoherent with the matrix is calculated to be about 100 MPa on the basis of the Orowan dislocation bypass mechanism. The increase of Cr content changes the number and size of nano-sized Cr phase, which causes the mechanical properties of the Cu-Cr-P alloys to increase first and then decrease. The tensile strength of Cu-0.36Cr-0.01P alloy is 572 MPa and its electrical conductivity is 80% IACS after solid solution treatment at 980 degrees C for 2 h followed by 95% cold rolling and then aging treatment at 450 degrees C for 1 h .
10.1016-S1003-6326(21)65529-2	15	aging; strength; conductivity; electrical conductivity; electrical; mpa; treatment; strengthening; degrees; cu-; cold; precipitation; tensile strength; tensile; iacs	The effects of Ni content (0-2.10 wt%) on the precipitated phase, strength and electrical conductivity of Cu-0.4wt%Be alloy were investigated, and the influencing mechanism was analyzed. The results showed that the addition of Ni promoted the precipitation of strengthening phase in the alloy and remarkably enhanced the strengthening effect. When the Ni content was increased from 0 to 2.10 wt%, the strength of the aged alloy initially increased and then decreased, and approached the maximum when the Ni content was 1.50 wt%. The peak-aging parameters of the alloy containing 1.50 wt% Ni were the aging temperature of 400 degrees C and the aging time of 60 min, where the tensile strength and yield strength of the aged alloy were 611 and 565 MPa, respectively, which were 2.8 times and 6.1 times those of the alloy without Ni. The electrical conductivity of the alloy with Ni increased with the aging time, and decreased with the increase of Ni content. With an increase of the aging time at 400 degrees C, phase transition sequence of the Cu-0.4Be-1.5Ni alloy was gamma '' phase ->gamma' phase ->gamma phase. For the aging time of 60 min, a large number of dispersed nano-scale coherent gamma '' phase and gamma' phase formed in the alloy with a remarkable strengthening effect, which was mainly responsible for the high strength of the alloy.
10.1016-S1003-6326(21)65557-7	2	corrosion; surface; film; electrochemical; films; spectroscopy; layer; current; solution; potential; resistance; composition; x-ray; ions; showed	The corrosion behavior of a copper-based shape memory alloy (Cu-Al-Mn-Zn-Zr) in 3.5 wt% NaCl solution was investigated by means of potentiodynamic polarization measurements, electrochemical impedance spectroscopy (EIS) and X-ray photoelectron spectroscopy (XPS). At the beginning of corrosion, oxidation products formed on the surface of the shape memory alloy and constantly covered the reaction surface, resulting in the decrease of corrosion rate. After 4 d of immersion in NaCl solution, the corrosion product layer became thick and porous, leading to the increase of corrosion rate, and the corrosion reaction mechanism changed from polarization control to diffusion control. The diffusion impedance increased with increasing thickness of the oxide layer for the samples immersed in NaCl solution for 6-15 d. During the whole corrosion process, the reaction mechanism of the alloy changed and the corrosion resistance was improved continuously. The corrosion products mainly contained CuO, ZnO, Al2O3, MnO/Mn2O3, MnO2 and Al(OH)(3). Transition of the corrosion products from Cu2O to CuO and Al2O3 to Al(OH)(3) occurred during corrosion.
10.1016-S1003-6326(21)65591-7	-1		To investigate the behaviors of Cu2+ and Ni2+ with the change of conditions in Cu2+-Ni2+-NH3-NH4+-C2O42--H2O reaction system, mathematical models of thermodynamics based on the principle of mass conservation were established. The simulation results indicate that the precipitation of metal ions from the aqueous phase is a complicated dynamic equilibrium process, during which the coordination reactions of Cu2+ and Ni2+ with NH3 forming [Cu(NH3)(n)](2+) (n=3-5) and [Ni(NH3)(m)](2+) (m=3-6) are predominant under high pH conditions, respectively. The pH ranges for the simultaneous precipitation of Cu2+ and Ni2+ are 2.0-6.5 and 2.0-5.5 when [NH3](T) equals 0.6 and 4.2 mol/L, respectively, with the prefixed [C2O42-](T) of 0.6 mol/L. Due to the fractional precipitation of Cu2+ and Ni2+, Cu-Ni composite is obtained after the thermal decomposition of Cu-Ni oxalate complex salts prepared in a pure water system when pH>7.0. By applying the mixed solvent (water/ethanol) as the precipitation medium, the Cu-Ni alloy rods can be finally fabricated with high purity and crystallinity.
10.1016-S1003-6326(21)65611-X	-1		This work aims to evaluate the feasibility of the fabrication of nanostructured Cu/Al/Ag multi-layered composites by accumulative roll bonding (ARB), and to analyze the tensile properties and electrical conductivity of the produced composites. A theoretical model using strengthening mechanisms and some structural parameters extracted from X-ray diffraction is also developed to predict the tensile strength of the composites. It was found that by progression of ARB, the experimental and calculated tensile strengths are enhanced, reach a maximum of about 450 and 510 MPa at the fifth cycle of ARB, respectively and then are reduced. The electrical conductivity decreased slightly by increasing the number of ARB cycles at initial ARB cycles, but the decrease was intensified at the final ARB cycles. In conclusion, the merit of ARB to fabricate this type of multi-layered nanocomposites and the accuracy of the developed model to predict tensile strength were realized.
10.1016-S1003-6326(21)65713-8	15	aging; strength; conductivity; electrical conductivity; electrical; mpa; treatment; strengthening; degrees; cu-; cold; precipitation; tensile strength; tensile; iacs	Cu-Fe alloys with different Fe contents were prepared by vacuum hot pressing. After hot rolling and aging treatment, the effects of Fe content on microstructure, mechanical properties and electrical conductivity of Cu-Fe alloys were studied. The results show that, when w(Fe)<60%, the dynamic recrystallization extent of both Cu phase and Fe phase increases. When w(Fe)>= 60%, Cu phase is uniformly distributed into the Fe phase and the deformation of alloy is more uniform. With the increase of the Fe content, the tensile strength of Cu-5wt%Fe alloy increases from 305 MPa to 736 MPa of Cu-70wt%Fe alloy, the elongation decreases from 23% to 17% and the electrical conductivity decreases from 31%IACS to 19%IACS. These results provide a guidance for the composition and processing design of Cu-Fe alloys.
10.1016-S1003-6326(21)65763-1	-1		Cu-0.15Zr (wt%) alloy with uniform and fine microstructure was fabricated by rapid solidification followed by hot forging. Evolution of microstructure, mechanical properties and electrical conductivity of the alloy during elevated-temperature annealing were investigated. The alloy exhibits good thermal stability, and its strength decreases slightly even after annealing at 700 degrees C for 2 h . The nano-sized Cu5Zr precipitates show significant pinning effect on dislocation moving, which is the main reason for the high strength of the alloy. Additionally, the large-size Cu5Zr precipitates play a major role in retarding grain growth by pinning the grain boundaries during annealing. After annealing at 700 degrees C for 2 h, the electrical conductivity of samples reaches the peak value of 88% (IACS), which is attributed to the decrease of vacancy defects, dislocations, grain boundaries and Zr solutes.
10.1016-S1003-6326(21)65789-8	6	grain; deformation; strain; strength; dislocation; cu-; tensile; size; ecap; grain size; sfe; ductility; hardening; high; stress	The effect of equal-channel angular pressing (ECAP) processing at room temperature and 300 degrees C on the distribution of the second phase particles and its influence on hardness and electrical conductivity of the commercial Cu-0.81Cr-0.07Zr alloy were investigated. Microstructural characterization indicated that the area fraction of coarse Cr-rich particles decreased after ECAP processing. This reduction was attributed to the Cr dissolution induced by plastic deformation. The electrical conductivity of the alloy decreased by 12% after 4 ECAP passes at room temperature due to the increase of electrons scattering caused by higher Cr content in solid solution and higher density of defects in the matrix. These results were supported by the reduction of the Cu lattice parameter and by the exothermic reactions, during differential scanning calorimetry (DSC) analysis, observed only in the samples subjected to ECAP processing. Aging heat treatment after ECAP processing promoted an additional hardening effect and the complete recuperation of the electrical conductivity, caused by the re-precipitation of the partially dissolved particles. The better combination of hardness (191 HV) and electrical conductivity (83.5%(IACS)) was obtained after 4 ECAP passes at room temperature and subsequent aging at 380 degrees C for 1 h .
10.1016-S1003-6326(22)65800-X	2	corrosion; surface; film; electrochemical; films; spectroscopy; layer; current; solution; potential; resistance; composition; x-ray; ions; showed	The anodic behaviour of pre-oxidised and non-oxidised Cu-Al-based anodes (Cu-10Al and Cu-9.8Al-2Mn) in KF-AlF3-Al2O3 melts was studied through galvanostatic and potentiodynamic polarization techniques. The alloy compositions were oxidised for a short-term (8 h) at 700 degrees C, followed by galvanostatic polarization for 1 h at 800 degrees C with an applied current density of 0.4 A/cm(2). The potentiodynamic curves were recorded with a sweep rate of 0.01 V/s. XRD analysis was conducted on frozen melt samples collected on the surface of the anode, and SEM observation was performed on the anode after the experiment to study the phases of the scales formed on the alloys. All the anode materials had a steady potential between 2.30 and 2.50 V (vs Al/AlF3). The corrosion rates of the anodes were calculated from the data acquired through potentiodynamic polarization. It was seen that pre-oxidised anodes possess a low corrosion rate compared to those without pre-oxidation treatment.
10.1016-S1003-6326(22)65868-0	17	wear; composites; coating; friction; composite; coatings; surface; tribological; properties; wear resistance; resistance; powder; sliding; matrix; wear rate	Gr/CuCr10 alloys with graphene contents of 0.1 wt%, 0.3 wt%, 0.5 wt%, and 0.7 wt% were prepared by a hot pressing sintering process. Compared with CuCr10 alloy, the relative density of CuCr10 composite with 0.3 wt% addition of graphene remained constant, while the electrical conductivity increased from 62.2% (IACS) to 69.5% (IACS). The main reason for the increased electrical conductivity is that the addition of graphene leads to the size reduction of Cr phase and thus reduces the scattering of electrons. In addition, Brinell's hardness of 0.3 wt% Gr/CuCr10 composite increased from HB 91.8 to HB 99.6 compared with that of CuCr10 alloy. The graphene was mainly distributed at the interface of Cu and Cr. A nano-Cr23C6 phase, which has been observed through HRTEM, is the main reason for the wettability enhancement at the interface of Cu and Cr, thus improving the hardness of the material.
10.1016-S1003-6326(22)65947-8	-1		Cu-2Cr-1Nb alloy was fabricated by spark plasma sintering (SPS) using close coupled argon-atomized alloy powder as the raw material. The optimal SPS parameters obtained using the L9(34) orthogonal test were 950 & DEG;C, 50 MPa and 15 min, and the relative density of the as-sintered alloy was 99.8%. The rapid densification of SPS effectively inhibited the growth of the Cr2Nb phase, and the atomized powder microstructure was maintained in the grains of the alloy matrix. Uniformly distributed multi-scale Cr2Nb phases with grain sizes of 0.10-0.40 mu m and 20-100 nm and fine grains of alloy matrix with an average size of 3.79 mu m were obtained. After heat treatment at 500 & DEG;C for 2 h, the room temperature tensile strength, electrical conductivity, and thermal conductivity of the sintered Cu-2Cr-1Nb alloy were 332 MPa, 86.7% (IACS), and 323.1 W/(m & BULL;K), respectively, and the high temperature tensile strength (700 & DEG;C) was 76 MPa.
10.1016-S1003-6326(22)65994-6	-1		The mechanical properties and microstructures of Al2O3 whiskers and graphene nano-platelets (GNPs) co-reinforced Cu-matrix composites were studied. Cu-matrix composites with a variation of GNPs amount were fabricated by mechanical alloying followed by vacuum hot-pressing sintering and hot isostatic pressing. The Cu-matrix composite with 0.5 wt% GNPs (GNPs-0.5) suggests a good interfacial bonding of both Cu/C and Cu/Al2O3 interfaces. Both the hardness and compressive strength of Cu-matrix composites show a consistent tendency that firstly increases to a critical value and then decreases with increasing GNPs amount. It is suggested that the most possible strengthening mechanisms of both GNPs and Al2O3 whisker working in the Cu-matrix composites involve energy dissipating and load transfer, as well as grain refinements for GNPs. The synergetic effect of GNPs and Al2O3 whiskers is highlighted that the embedded GNPs would hinder the crack path generated at the Al2O3/Cu interface and enhance the already outstanding strengthening effect that Al2O3 whiskers provide.
10.1016-S1003-6326(22)66031-X	-1		This research aims to extract Cu from Cu-Co alloy with high efficiency and selectivity by employing binary Mg-Pb melt. The optimal conditions for the extraction of Cu were determined. The results showed under optimal conditions, 96.5% of Cu in the Cu-Co alloy could be selectively extracted after treatment at 800 degrees C for 1 h, with the extraction rates of only 0.2% Fe, 0.6% Co, and 1.4% Si. The dissolution mechanism involved the counter diffusion of Mg/Pb and Cu across the diffusion zone of the Cu-Co alloy, and Mg in the binary Mg-Pb melt played a major role in the selective dissolution of Cu, especially at the dissolution forefront. The rate-controlling step of the extraction was dominated by the interfacial reaction.
10.1016-S1003-6326(23)66149-7	12	thermodynamic; ternary; phase; data; experimental; equilibria; phase equilibria; liquid; binary; experimental data; calculated; phases; literature; model; calphad	The phase equilibria of the Cu-Nb-Si system were investigated via a combination of key equilibrated alloys, thermodynamic modeling and first-principles calculations. Sixteen ternary alloys were prepared to determine the isothermal sections at 600 and 700 degrees C, by means of X-ray diffraction (XRD) and scanning electron microscopy with energy dispersive X-ray spectroscopy (SEM-EDS). The three-and two-phase regions were determined. The existence of ternary compound tau 1 (Cu4Nb5Si4) was confirmed. The solubilities of Cu in the NbSi2 and Nb5Si3 phases were measured. Based on the experimental equilibria data from the literature and the present work, a thermodynamic description of the Cu-Nb-Si system was carried out by using the calculation of phase diagrams (CALPHAD) method supported by first-principles calculations. The substitutional model and sublattice model were employed to describe the solution phases and intermediate phases, respectively. A set of self-consistent thermodynamic parameters of the Cu-Nb-Si system were conclusively obtained. Most of the reliable experimental data were reproduced by the present thermodynamic modeling.
10.1016-S1003-6326(23)66150-3	8	hot; deformation; strain; strain rate; dynamic; hot deformation; recrystallization; dynamic recrystallization; flow; rate; flow stress; compression; constitutive; degrees; stress	The hot deformation characteristics of Cu-13Zn-1Ni-1Sn-1.5Al gold- imitation brass alloy in a temperature range from 953 to 1123 K and a strain rate range from 0.001 to 1 s(-1) were investigated by hot compression tests. The stress-strain curves show that the flow stress decreases with the increase of temperature and the decrease of strain rate. The dynamic recrystallization grains appear while the temperature reaches 1073 K at a constant strain rate of 0.01 s(-1). The constitutive equation of the alloy was established and its deformation activation energies were obtained at different strains (epsilon=0.1, 0.2, 0.3, 0.4, 0.5, 0.6, 0.7, 0.8). When the strain is 0.8, the constitutive equation of the alloy is epsilon = 7.22x10(9)[sinh(0.0187 sigma)](3.67)exp[-227.17/(RT)], and the deformation activation energy is 227.17 kJ/mol. The dissipation power maps and instability maps were established at different strains, which suggested that the recommended processing condition for hot compression was in the temperature range of 1010-1040 K with a strain rate of 1 s(-1).
10.1016-S1003-6326(23)66195-3	1	shape; memory; shape memory; damping; martensite; martensitic; damping capacity; transformation; capacity; strain; superelasticity; temperature; cu-al-mn; shape memory effect; effect	The Cu-13.5Al-4Ni-6Fe centimeter-leveled martensite single crystals with full shape memory effect were prepared through simply annealing the cast alloy. The microstructure, reversible martensitic transformation, shape memory effect of this single crystal were investigated using optical microscopy, transmission electron microscope, differential scanning calorimeter, thermal mechanical analysis and compression test. The results show that Cu-13.5Al-4Ni-6Fe single crystal consists of 18R and 2H martensite, as well as rich-Fe bcc nanoprecipitate. The starting temperatures and the finishing temperatures of the forward and reverse martensitic transformations are 387, 397, 365 and 432 K, respectively. When the pre-strain is 6%, 7%, and 8%, this single crystal exhibits full shape memory effect of 4.4%, 4.7% and 5.2%, respectively. The obtained Cu-13.5Al-4Ni-6Fe martensite single crystal possesses shape memory properties that can be comparable to those of traditional shape memory alloys.
10.1016-S1003-6326(23)66196-5	-1		A 3D finite element model was developed. The accuracy of the model was verified through a rolling experiment in which the reduction rate of the plate was 50%. The metal flow law in the rolling process was analyzed from the perspective of time during the whole corrugated rolling process. The deformation experienced by all metal particles is divided into two periods: the filling period and the extension period. The stress change is complex during the filling period, but the stress change trend is approximate during the extension period. The stress state of characteristic positions is two tensile stresses and one compressive stress when the plate starts to deform, which was analyzed by the Lode angle parameter and triaxiality parameter. The microstructure evolution of the Cu plate was analyzed using electron backscatter diffraction (EBSD) technology. Compared with the initial plate, grain refinement occurs at each characteristic position of the Cu plate. There is a phenomenon of grain growth at the trough of the Cu plate after refinement due to the adiabatic temperature increase caused by severe plastic deformation.
10.1016-S1003-6326(23)66271-5	15	aging; strength; conductivity; electrical conductivity; electrical; mpa; treatment; strengthening; degrees; cu-; cold; precipitation; tensile strength; tensile; iacs	Cu-1.0Cr-0.1Zr alloy strips were prepared by solution, cold rolling and aging processes. The effects of aging process on the conductivity, mechanical properties and microstructure of the alloy were studied, and the precipitation kinetics was analyzed. The results showed that the Cu-1.0Cr-0.1Zr alloy exhibited the best comprehensive properties after aging at 430 degrees C for 180 min, with an electrical conductivity of 85.86% IACS, a hardness of HV 176.54, and a tensile strength of 552 MPa. For the samples aged at 430 degrees C from 30 to 180 min, the fcc-Cr and Cu8Zr3 phases grew from-5 to-8 nm, and the relationship between the precipitates and matrix changed from coherent to semi-coherent. In addition, the rod-like and spherical coarse particles (>= 300 nm) of bcc-Cr phase were observed. The precipitation kinetics equations at different aging temperatures were established, the time-temperature-transformation (TTT) curve was plotted, and the precipitation activation energy was obtained as 65 kJ/mol.
10.1016-S1003-6326(23)66292-2	-1		A new Cu-La-Zn alloy system with high thermal conductivity was developed for die casting, and the thermal conductivity of this alloy system was 200-300 W/(m center dot K), which was twice as that of ordinary brass. The effects of Cu6La intermetallic compounds and Zn solute atoms on the strengthening and thermal conductivity behaviors were quantitatively studied in as-cast binary Cu-La (2.0-4.5 wt% La) and ternary Cu-2La-xZn (0-3.0 wt% Zn) alloys, respectively. The results showed that for the increase of per 1 wt% La or Zn, the thermal conductivity decreased by about 34 W/(m center dot K). In Cu-2La-xZn alloys, the lattice constant of alpha-Cu matrix increased from 3.6163 to 3.6239 angstrom. Due to the solid solution strengthening of Zn atoms, the hardness of the alpha-Cu matrix showed a parabolically increasing tendency, from 1.495 to 1.597 GPa. According to the calculations of the Maxwell-Eucken model based on the microstructure, the thermal conductivity of Cu6La phase was determined to be about 35.37 W/(m center dot K), and the reduction in thermal conductivity of alpha-Cu matrix caused by Zn solute atoms was quantified to be 51.38 W/(m center dot K) per 1.0 at% Zn increase.
10.1016-S1003-6326(23)66343-5	-1		Cu-Y2O3 and Cu-Y2O3-Zr composites were prepared via mechanical alloying and spark plasma sintering, and their microstructure and properties were systematically studied by using optical metalloscope, scanning electron microscope, transmission electron microscope, conductivity and tensile tests. It is found that the microstructure of the composites greatly affects mechanical behavior and electrical conductivity. The improvement of electrical property can be attributed to the formation of coherent Y4Zr3O12 particles and the preferential nucleation of Cu4Zr phase, which improves the interface between Y2O3 and Cu matrix, and reduces the dislocation density, respectively. In addition, the Cu-Y2O3-Zr composites can achieve 265.6 MPa of yield strength, 301.0 MPa of ultimate tensile strength, 23.6% of elongation, and 92.0%(IACS) of electrical conductivity.
10.1016-S1003-6326(23)66443-X	-1		The effects of melt superheat and pulsed magnetic field on the microstructure, mechanical and wear properties of the Mn5Si3 reinforced Cu-35Zn-3Al alloy were investigated. The results indicate that after the combined treatments, the hollow formation on the prism-shaped Mn5Si3 particles is inhibited, due to the enhanced solute migration in melt and promoted adsorption kinetics for crystal growth . The tensile strength and elongation of the forged alloy increase by 9.0% and 66.5%, respectively. The failure type of Mn5Si3 particles during tension transfers from brittle cleavage fracture to pulling out of the matrix due to the higher fracture strength with diminished stress concentration, which leads to enhanced reinforcement of matrix/particle load transfer. The wear resistance of alloy is significantly improved because of reduced delamination wear, since the severe shear fracture on the Mn5Si3 particles with hollows under friction induced plastic deformation is restrained, alleviating the subsurface originated crack propagation and spalling.
10.1016-S1003-6326(24)66492-7	-1		The influence of various Fe contents (5, 10, 20, and 40 wt%) on the microstructure and properties of powder metallurgy Cu-Fe alloy by spark plasma sintering, subjected to cold rolling and aging treatments, was explored. The results showed that, with increasing Fe content from 5 wt% to 40 wt%, the distribution of Fe phase evolved from the discrete spheroid to the continuous stagger, accompanying with its size increasing from 0.29 to 1.20 mu m. Accordingly, the yield strength of the aged alloy increased from 411.5 to 788.8 MPa, whilst the electrical conductivity decreased from 62.5% (IACS) to 42.0% (IACS). Moreover, a rule of mixture was proposed to calculate the contribution of Cu matrix, primary Fe phase and secondary Fe phase to the yield strength of the alloy, which works well in the prediction of mechanical properties for Cu-Fe alloys with Fe content higher than10 wt%.
10.1016-S1003-6326(24)66513-1	0	solidification; phase; magnetic; magnetic field; undercooling; field; liquid; separation; peritectic; immiscible; cu-; dendrite; phase separation; microstructure; primary	Non-equilibrium solidification experiments were conducted on Cu50Co50 50 Co 50 alloys under different magnetic field intensities to investigate the orientation, microstructure evolution, and magnetic properties of the Co-rich phase. The results revealed that the phase-separated rod-like Co-rich phase can realize the alignment morphology and can be oriented with the < 111 > crystal direction along the direction of the 5 T high magnetic field (HMF). In contrast, the orientation of the Cu-rich phase, which underwent secondary liquid-liquid phase separation, was not significantly affected by the HMF. The alloy solidified at 0 T showed near-magnetic isotropic behavior, while the alloy solidified at 5 T displayed magnetic anisotropic behavior. The saturation magnetization of the alloy increased slightly, and the coercivity decreased correspondingly, which were strictly dependent on the orientation evolution of the Co-rich crystal.
10.1016-S1003-6326(24)66562-3	-1		The damage characteristics of different speed sections of Cu-Cr-Zr alloy rail after simulated launch were studied. The microstructure, morphologies and properties of samples were investigated by using XRD, XPS, EBSD, SEM, hardness test, electrochemical test and DSC techniques. It was found that deposition layers were formed on the surfaces of the simulated launch samples. The thickness and surface roughness of these deposition layers increased with increasing the heat effect, suggesting a launch speed dependent damage degree of the arc ablation. The hardness variation of samples is attributed to the effects of the deposition layer and deformation hardening. The surface deposition layer affects corrosion resistance and crystalline characteristics, leading to changes in subsequent service performances. Additionally, the surface texture and plastic deformation ability of the samples are related to the recrystallization degree and deformation grain amount.
10.1016-S1003-6326(24)66584-2	15	aging; strength; conductivity; electrical conductivity; electrical; mpa; treatment; strengthening; degrees; cu-; cold; precipitation; tensile strength; tensile; iacs	The recrystallization and softening resistance of a Cu-6.5Fe-0.3Mg (mass fraction, %) alloy prepared by Process 1 (cold rolling heat treatment) and Process 2 (hot/cold rolling heat treatment) were studied using Vickers hardness tests, tensile tests, scanning electron microscopy and transmission electron microscopy. The softening temperature, hardness and tensile strength of the alloy prepared by Process 2 were 110 degrees C, HV 15 and 114 MPa higher, respectively, than those of the alloy prepared by Process 1 after aging at 300 degrees C. The recrystallization activation energy of the alloys prepared by Process 1 and Process 2 were 72.83 and 98.11 kJ/mol, respectively. The pinning effects of the precipitates of the two alloys on grain boundaries and dislocations were basically the same. The softening mechanism was mainly attributed to the loss of dislocation strengthening. The higher Fe fiber density inhibited the average free migration path of dislocations and grain boundary migration in the alloy, which was the main reason for higher softening temperature of the alloy prepared by Process 2.
10.1016-S1003-6326(24)66605-7	-1		The recrystallization behavior, grain boundary characteristic distribution, and mechanical properties of pure Cu sheets that were subjected to different cold rolling paths, and then annealed at 400 degrees C for 10, 30, 60, and 420 min, were investigated. Different rolling paths changed the grain boundary orientations of cold-rolled copper, causing recrystallized grains to nucleate and grow in an oriented manner. However, the evolution of the texture indicated that cold-rolled copper with different rolling paths did not show an obvious preferred orientation after annealing. The RD-60 specimen exhibited the smallest grain size (6.6 mu m). The results indicated that the grain size and low-Sigma CSL grain boundaries worked together to provide RD-60 samples with appropriate mechanical properties and high plasticity. The yield strength, ultimate tensile strength, and elongation of RD-60 sample were 81 MPa, 230 MPa, and 49%, respectively. These results could provide guidance for tuning the microstructures and properties of pure Cu foils, as well as designing fabrication routes for pure Cu foils through processes such as rolling and drawing.
10.1016-S1003-6326(24)66607-0	-1		In order to improve the comprehensive properties of the Cu-11.9Al-2.5Mn shape memory alloy (SMA), multilayer graphene (MLG) carried by Cu51Zr14 inoculant particles was incorporated and dispersed into this alloy through preparing the preform of the cold-pressed MLG-Cu51Zr14 composite powders. In the resultant novel MLG/Cu-Al-Mn composites, MLG in fragmented or flocculent form has a good bonding with the Cu-Al-Mn matrix. MLG can prevent the coarsening of grains of the Cu-Al-Mn SMA and cause thermal mismatch dislocations near the MLG/Cu-Al-Mn interfaces. The damping and mechanical properties of the MLG/Cu-Al-Mn composites are significantly improved. When the content of MLG reaches 0.2 wt%, the highest room temperature damping of 0.0558, tensile strength of 801.5 MPa, elongation of 10.8%, and hardness of HV 308 can be obtained. On the basis of in-depth observation of microstructures, combined with the theory of internal friction and strengthening and toughening theories of metals, the relevant mechanisms are discussed.
10.1016-S1003-6326(24)66641-0	-1		Copper matrix composites (CMCs) offer promising applications by combining the functional characteristics of copper with composite phases. With the rapid advancement in aerospace, microelectronics, and intelligent terminal engineering, the demand for CMCs with superior mechanical and electrical properties has become increasingly critical. This paper reviews the design principles, preparation methods, microstructures and properties of some typical CMCs. The existing form of composite phases in the Cu matrix and their effects on microstructure evolution and comprehensive properties are summarised. Key underlying mechanisms governing these enhancements are discussed. The results provide a systematic understanding of the relationship between reinforcement phases and properties, offering insights for the future development of CMCs aimed to achieve much better comprehensive properties. The paper concludes by outlining the development trends and future outlook for the application of CMCs.
10.1016-S1003-6326(24)66652-5	-1		The segregation of Sn and discontinuous precipitation at grain boundaries are detrimental to the strength, ductility, and machinability of the Cu-Ni-Sn alloy. A strategy to solve the above problems is multi-component composition design by introducing strong enthalpic interaction element. In this work, a series of Cu80Ni15Sn5-xTix (at%) alloys were designed by cluster-plus-glue-atom model, and the effects of Ti content on the microstructure and properties of the alloys were systematically investigated using TEM and other analysis methods. The results demonstrate that Ti can effectively inhibit the segregation and discontinuous precipitation while promoting continuous precipitation to improve the high-temperature stability of the alloys. As the Ti content increases, the distribution of Ti changes from uniform distribution to predominant precipitation. The hardness and conductivity of the alloy exceed those of the C72900 (Cu-15Ni-8Sn (wt%)) commercial alloy and the Cu80Ni15Sn5 (at%) reference alloy when Ti is in the solution state.
10.1016-S1003-6326(24)66721-X	-1		The effects of trace cerium (Ce) addition on the microstructural and textural evolution and the dynamic recrystallization (DRX) of the ultrahigh-purity copper (Cu) containing small amounts of sulfur (S) were investigated using a Gleeble-1500 thermal simulation tester at 600 degrees C. The results show that with increasing Ce content, the grain size of the Cu-S (S2) alloy gradually decreases and the grain boundary embrittlement induced by S impurities is considerably inhibited. The addition of Ce promotes the DRX process of the S2 alloy and changes its DRX mechanism from discontinuous to continuous and twinning-induced DRX mechanisms. The texture component and intensity of the S2 alloy vary with the increase of Ce content. The addition of 120x10-6 Ce (mass fraction) is favorable for the grain orientation randomization, which is attributed to the promoted DRX.
10.1016-S1003-6326(24)66743-9	-1		The effects of forward extrusion as well as extrusion combined with reversible torsion (KoBo extrusion), followed by additional deformation via the MaxStrain module of the Gleeble thermomechanical simulator, on the microstructure, mechanical properties, and electrical conductivity of a Cu-0.7Mg (wt%) alloy, were investigated. The simulation results highlighted the critical influence of processing history on determining the equivalent strain distribution. The sample subjected to forward extrusion at 400 degrees C and subsequent MaxStrain processing (FM sample), possessed 76% lower grain size compared to the sample processed solely with MaxStrain (AM sample). Likewise, the KoBo-extruded and MaxStrain-processed sample (KM sample) exhibited 66% smaller grain size compared to the AM sample. Tensile test results revealed that the AM, FM, and KM samples, respectively, possessed 251%, 288%, and 360% higher yield strength, and 95%, 121%, and 169% higher tensile strength compared to the initial annealed alloy, as a result of grain refinement as well as deformation strengthening. Finally, the electrical conductivity measurements revealed that AM, FM, and KM samples, respectively, possessed electrical conductivity values of 37.9, 35.6, and 32.0 MS/m, which, by considering their mechanical properties, makes them eligible to be categorized as high-strength and high-conductivity copper alloys.
10.1016-S1003-6326(24)66744-0	-1		A novel Cu-4.8Cr-2.2Nb-0.15Y (at%) alloy was fabricated by employing the laser powder bed fusion with different processing parameters. The influence of laser power (P), scanning speed (v), and laser linear energy density (E-l) on the defects, melt pool morphology, microstructure, and properties of the alloy was systematically investigated. The results show that the optimized process parameters for preparing Cu-Cr-Nb-Y alloy with relative density over 99.5% are P=300-350 W and v=650-800 mm/s, corresponding to E-l=0.375-0.538 J/mm. When E-l < 0.3 J/mm, increasing P or decreasing v can enhance the continuity and size of the melt pool, reduce the lack-of-fusion defects, and increase the relative density. However, excessively high E-l leads to a deeper melt pool, more keyholes, and reduced relative density. The grain size of the as-built Cu-Cr-Nb-Y alloy shows a bimodal distribution, with fine grains at the center and coarse grains at the edge of the melt pool. Increasing P or decreasing v increases the average grain size and < 110 > texture intensity. The alloy fabricated with P=350 W and v=800 mm/s displays the highest relative density of 99.82%. The yield strength, tensile strength, and elongation are (443 +/- 5) MPa, (699 +/- 4) MPa, and (17.1 +/- 0.7)%, respectively.
10.1016-S1003-6326(25)66771-9	14	strength; properties; conductivity; electrical; mechanical; cu-; grain; mpa; electrical conductivity; aging; precipitation; phase; mechanical properties; tensile; phases	To optimize the comprehensive properties of Ni-Si precipitation strengthened phosphor bronze, the impact of the Ni/Si mass ratio and heat treatment process on a Cu-8Sn-0.1P-1Ni-xSi alloy was explored. High resolution field emission scanning electron microscopy and transmission electron microscopy were used for microstructural characterization. The results indicate that the properties are influenced by the Ni/Si mass ratio, attributed to the formation of various second phases. Simultaneously, by influencing the diffusion rate, the microstructures and properties are influenced by the solid solution treatment. The strength is enhanced by precipitated nanoscale particles during the aging process by influencing the motion of dislocations. Ultimately, excellent comprehensive properties, including ultimate tensile strength, yield strength, and elongation of 866 MPa, 772 MPa, and 8.7%, respectively, are obtained in the Cu-8Sn-0.1P-1Ni-0.227Si alloy.
10.1016-S1003-6326(25)66839-7	-1		The phase equilibria of the Cu-Zr-Si system at 600 degrees C were experimentally studied by means of X-ray diffraction (XRD) and scanning electron microscopy with energy dispersive X-ray spectroscopy (SEM-EDS). A comprehensive set of thermodynamic parameters for the Cu-Zr-Si system were obtained through detailed analysis using the CALPHAD (CALculation of PHAse Diagrams) approach . Based on the CALPHAD calculations, five as-cast alloys were designed, and the Scheil-Gulliver model was used to simulate their solidification paths. By testing hardness, friction and wear properties, the wear resistance of the Cu-Zr-Si alloys was investigated. Wear morphologies were analyzed using SEM and 3D profiling techniques. It was found that the alloy Cu80Zr19Si1 exhibits a good performance with a hardness of HV 342, frictional coefficient of 0.23 and wear rate of 2.19x10-7 mm3/(Nm). The wear surfaces are mainly characterized by grooves, spalling pits and oxide particles. The wear mechanism of the alloys is adhesive wear and oxidative wear under dry sliding condition. This study provides a theoretical basis for the design of the wear-resistant Cu-Zr-Si alloys.
10.1016-S1003-63262466745-2	14	strength; properties; conductivity; electrical; mechanical; cu-; grain; mpa; electrical conductivity; aging; precipitation; phase; mechanical properties; tensile; phases	The effect of adding Cr and Mg on the microstructure and properties of Cu-Ti alloys was examined. Cu-Ti-Cr-Mg alloys were fabricated using vacuum induction melting. The microstructure and phase composition of Cu-Ti-Cr-Mg alloys in different aging states were characterized. Additionally, the hardness and electrical conductivity of the materials were investigated. Results show that the precipitation pattern in Cu-Ti-Cr-Mg alloys resembled that of binary Cu-Ti alloys, with Cr and Ti forming the intermetallic compound of Cr2Ti during casting. The introduction of Cr and Mg increased the hardness of the alloy. Increasing the Mg content in the Cu-Ti-Cr-Mg alloy led to grain refinement and fast nucleation of continuous precipitates during the early aging stage. Moreover, the addition of Mg impeded discontinuous precipitate growth by segregating along the precipitate surfaces. Consequently, the Cu-4Ti-0.5Cr-1Mg alloy exhibited limited discontinuous precipitates at the grain boundaries and a gradual decline in hardness during the over-aging period.
10.1016-S1005-8850(07)60105-4	-1		The bulk metallic glass formation in the Cu-Zr-M ternary systems by alloying of a binary basic Cu6Zr5 cluster was investigated, where M stands for Sn, Mo, Ta, Nb, Ag, Al and Ti. The Cu6Zr5 cluster is a capped Archimedean antiprism that characterizes the local structure of the Cu10Zr7 crystalline phase. This cluster composition almost superposes with Cu-Zr eutectic Cu0.56Zr0.44. A series of alloys along the cluster line (Cu6Zr5)(1-x)M-x were examined for their glass forming abilities. Alloy rods with a diameter of 3 mm were prepared by copper mould suction casting method and analyzed by XRD and thermal analysis. The Cu-Zr based bulk metallic glasses were discovered with minor Nb, Sn, Mo, Ta additions (<= 2at%) and Al, Ti, Ag (8at%<= concentration <= 9at%). The alloying mechanism was discussed in the light of atomic size, cluster-linking structure and electron concentration factors.
10.1016-S1006-706X(16)30007-3	11	glass; bulk; metallic; bulk metallic; gfa; bmg; glassy; metallic glass; ability; bulk metallic glass; amorphous; addition; crystallization; mm; glass-forming	Compositional dependences on microstructures and martensitic transformation behaviors in (Cu0.5Zr0.5)(100-x)Zn-x (x=1. 5, 2. 5, 4. 5, 7. 0, 10. 0, and 14. 0 at. %) alloys were investigated. It was found that CuZr martensites were present in the present alloys. With increasing Zn content, the volume fractions of CuZr martensitic crystals and B2 CuZr phase gradually decrease and increase, respectively. With the addition of high Zn contents (i.e. 7. 0, 10. 0, and 14. 0 at. %) the matrix proves to be eutectic. Thermal analysis results show that the initial martensitic transformation temperature (M-s) decreases from (412 +/- 5) K to (329 +/- 5) K as the Zn content increases from 1. 5 at. % to 14. 0 at. %. The values of M-s of Cu-Zr-Zn shape memory alloys are inversely proportional to the number and concentrations of valence electrons (i. e., e(v)/a and c(v)), respectively, implying that the martensitic transformation in CuZr-Zn alloys could be of electronic nature.
10.1016-S1006-706X(17)30061-4	0	solidification; phase; magnetic; magnetic field; undercooling; field; liquid; separation; peritectic; immiscible; cu-; dendrite; phase separation; microstructure; primary	A single crystal Cu-lwt. Yo Fe alloy with finely dispersed iron-rich nanoparticles which keep coherent interface with the copper matrix was prepared under directional solidification. Formation of nanoparticles in the alloy melt was investigated by performing differential scanning calorimeter tests and designed water quenching experiment at a certain temperature. Results show that iron-rich nanoparticles are formed in the Cu-1wt Yo Fe alloy melt before primary a-Cu forms, which is not consistent with equilibrium phase diagram. Mechanism that iron-rich nanoparticles are uniformly captured in the matrix was described, which is that numerous nanoparticles follow Brownian motions and are engulfed in the solidified matrix which makes it possible to form uniformly distributed nanoparticles reinforced single crystal Cu-lwt. Yo Fe alloy.
10.1016-S1044-5803(00)00059-0	4	transformation; martensite; martensitic; phase; shape; beta; memory; shape memory; temperature; temperatures; martensitic transformation; gamma; transformation temperatures; effect; thermal	After the treatment for the Stabilization of Stress-Induced Martensite (SSIM) in Cu-Zn-Al alloys, it was found that the small gamma precipitates in the beta austenite are ellipsoidal with a large strain field oriented in the same direction, while in the martensite, the gamma precipitates changed their shape from ellipsoidal to spheroidal, which relaxed the strain field. To check whether the strain field of the gamma precipitates is available to produce thermoelastic martensitic transformation, in situ observations with a heating sample holder in TME were performed. It was found that after heating above the A(s) temperature, the spherical gamma precipitates in the martensite recovered their strain field and elliptical shape. During cooling, the strain field of the gamma precipitates disappeared again. This means that the strain fields of the gamma precipitates trained by the SSIM method play an important part in the thermoelastic martensitic transformation that presents the two-way shape memory effect. (C) Elsevier Science Inc., 2000. All rights reserved.
10.1016-S1044-5803(01)00137-1	1	shape; memory; shape memory; damping; martensite; martensitic; damping capacity; transformation; capacity; strain; superelasticity; temperature; cu-al-mn; shape memory effect; effect	The martensitic transformation and shape memory effect (SME) in a beta Cu-Zn alloy containing various amounts of a, plates have been investigated. The results showed that the characteristic temperature of martensitic transformation decreased as the isothermal aging time increased. The crystal structure, twin relationships between martensite variants, and characteristics of martensitic transformation of the beta Cu-Zn alloy were not affected by the existence of alpha (1) plates. However, the alpha (1) plates were distributed homogeneously in the parent phase and functioned as grain boundaries, hindering the progress of martensite variants, and reducing the effective grain size of the parent phase and the size of self-accommodating plate groups formed upon cooling. In addition, the strain recovery due to the SME decreased as the isothermal aging time increased (the quantity of alpha (1) plate increased) and/or imposed prestrain increased. Nevertheless, the SME mechanism in the beta Cu-Zn alloy containing a, plates was not affected by the presence of the alpha (1) plates.
10.1016-S1044-5803(02)00256-5	-1		The goal of this study was the determination of the residual macroscopic stresses in titanium nitride (TiN) coatings deposited by DC planar magnetron sputtering (DCPMS) on a ternary copper alloy (Cu-3% Ti-1% Cr) under different conditions of applied current intensity, ArN(2) flow ratio and bias voltage. The residual stresses were measured by X-ray diffraction (XRD) with a grazing technique for films of 1 mum thickness. These stresses are mainly due to a growth intrinsic stress. The total stresses have a small contribution of thermal stress, which is not important at the process temperature, in comparison with intrinsic stress. The residual stresses that were obtained are in traction or compression depending on the process parameters used during deposition. These results are analysed with respect to the measures obtained for lattice parameter free of deformation, grain size (GS), adhesion of the coat on the substrate, microhardness and chemical composition of the coating, trying to obtain a relation of the stress evolution with these process parameters.
10.1016-S1359-6454(00)00096-3	-1		The growth behavior of fine grains produced due to diffusion induced recrystallization (DIR) was experimentally studied for the Cu(Zn) system using single crystal Cu specimens. The Cu specimens were annealed at 693 K for various times together with st Zn source alloy by a capsule zincification technique and then DIR was observed to take place on the surfaces of the specimens. The DIR region consists of an almost single layer of fine grains. Although the average height I and the average diameter s of the fine grains increase with increasing annealing time, the aspect ratio s/l is kept to be nearly unity during annealing. The Zn concentration on the specimen surface is smaller than that in the Zn source alloy at early stages of the reaction. Such lower Zn concentrations could be explained using the maximum driving force model proposed by Kajihara and Gust (Acta metall. mater., 1991, 39, 2565). The composition on the specimen surface gradually approaches the equilibrium value with increasing annealing time. This means that the amount of the Zn source alloy is large enough to maintain the supply of Zn atoms to the specimen in each zincification capsule. The kinetic model by Li and Hillert (Acta metall., 1981, 29, 1949) and the extended model by Kawanami ct al. (ISIJ int., 1997, 37, 921) could rather well reproduce the annealing time dependence of the growth rate of the DIR region. The contribution of volume diffusion to the transfer of Zn atoms from the surface to the moving boundaries in the DIR region was estimated to be negligible. Thus, the chemical driving force is considered to be the most important driving force for the grain boundary migration and the boundary diffusion along the grain boundaries in the DIR region is recognized to be the rate controlling process of DIR. (C) 2000 Acta Metallurgica Inc. Published by Elsevier Science Lid. AII rights reserved.
10.1016-S1359-6454(00)00185-3	-1		A Cu-Co alloy powder was produced by water atomisation and a powder fraction was subsequently consolidated by hot isostatic pressing. The precipitation behaviour in this rapidly solidified Cu-Co alloy powder was investigated by a combination of magnetic measurements, X-ray diffraction, transmission electron microscopy structural studies and microhardness measurements. The magnetic measurements are a sensitive technique for monitoring the early stages of precipitation from the supersaturated solid solution produced by rapid solidification. Small cobalt clusters were detected already in the as-atomised powder. The hardening observed for the low-temperature heat treatments (up to peak hardness) is correlated with the precipitate sizes derived from magnetic measurements, allowing a rationalisation of the observed hardening in terms of coherency strengthening.
10.1016-S1359-6454(00)00377-3	6	grain; deformation; strain; strength; dislocation; cu-; tensile; size; ecap; grain size; sfe; ductility; hardening; high; stress	Copper single crystal with dispersed sphere SiO2 particles were cyclically deformed at the temperatures between 298 K and 673 K. Cu-SiO2 alloy showed longer life compared with pure copper irrespective of temperature and stress amplitude. This would be due to matrix strengthening not only by dispersion but also by development of cell structures in which the dispersed particles behave as their nodes. At higher temperatures, occurrence of stress relaxation around the Cu/SiO2 interface lowered stress-amplitude dependency of slope (Delta epsilon/Delta logN). The observed easy nucleation of fine voids at the Cu/SiO2 interface seemed not to lower the fatigue strength nor shorten the life.
10.1016-S1359-6454(01)00168-9	-1		The thermomechanical behavior of metallic thin films on stiff substrates is relevant for thin-film devices, but its mechanisms are not fully understood. In this investigation, the mechanical properties of pure Cu and Cu-1 at% Al films on diffusion-barrier coated Si substrates were studied with the wafer-curvature technique. In ultra-pure films, which were sputtered and annealed under ultra-hi.-h vacuum conditions, characteristic stress relaxation at high temperatures was measured, which could be clearly attributed to diffusional creep. Good quantitative agreement with a recent model of diffusional creep constrained by a substrate was obtained. These features were absent in the Cu-Al alloy films, in which Al surface segregation and oxidation had produced a self-passivating effect, and in films produced in less clean environments. Based on these results, we propose a model of thin-film deformation based on dislocation glide and constrained diffusional creep.
10.1016-S1359-6454(01)00248-8	-1		By means of the electrodeposition technique, a bulk nanocrystalline (nc) copper sample was prepared with a high purity and a high density. The nc Cu sample was found to exhibit extreme extensibility under rolling at room temperature [Science, 287 (2000) 1463]. In this paper, the microstructure evolution of the nc Cu during the cold-rolling process was examined by means of X-ray diffraction (XRD) analysis, transmission electron microscopy (TEM) and differential scanning calorimetry (DSC). It was found in the initial stage of cold rolling that the microstrain and grain boundary energy increase substantially, while the crystallite size remains unchanged during the whole process. When the degree of deformation exceeds 1000%, the microstrain and the.-rain boundary energy tend to saturated values, implying that this deformation process is dominated by grain boundary activity rather than lattice dislocation. This phenomenon agrees well with the observed mechanical behavior of the nc Cu sample.
10.1016-S1359-6454(01)00308-1	4	transformation; martensite; martensitic; phase; shape; beta; memory; shape memory; temperature; temperatures; martensitic transformation; gamma; transformation temperatures; effect; thermal	Compression tests have been carried out for a Cu-AI-Ni single crystal at temperatures well above the martensitic transformation. near the transformation or below it (in martensitic state). The composition was selected in order to obtain either beta-beta' or beta-gamma' thermal martensitic transformations, after suitable thermal treatments. The characteristics of the martensitic transformation and structural changes after the compression tests have been studied by means of calorimetry (DSC) and TEM. The obtained results show that when a compressive stress is applied on quenched samples (TTA treatment, beta-beta' thermal transformation) a beta beta-(beta')-gamma' transformation or a beta'-gamma' one are stress-induced, depending whether the initial state is the parent or the martensitic phase. For aged samples (TTB treatment, beta-gamma' thermal transformation) the application of stress brings about the beta-gamma' transformation or gamma' re-orientation, depending on the initial state. In all the cases a notable martensite stabilisation is observed only when the stress-strain loop is not closed. that means when a permanent strain remains in the material after unloading. A direct relationship between the applied deformation when stressing the sample and the degree of stabilisation has been obtained for different strain values (between 5% and 12%) and for each set of samples (TTA and TTB). At the same time, the evolution of the characteristics of the martensitic phases with the degree of deformation has been studied. The stress induced stabilisation mechanism is related to the presence of non-twinned gamma' martensite which makes difficult the retransformation to the parent phase.
10.1016-S1359-6454(01)00381-0	6	grain; deformation; strain; strength; dislocation; cu-; tensile; size; ecap; grain size; sfe; ductility; hardening; high; stress	High-purity Cu-2%Al single crystals with initial C{112}<111> orientation have been deformed by channel-die compression at 77 and 293 K to develop fine shear bands in a twin-matrix (T-M) substructure. The microstructural and microtextural changes during deformation and the early stages of recrystallization have been studied in detail by TEM/CBED and SEM/EBSD. Local orientations measurements indicate that the scattering of the original T-M orientations within shear bands towards two, twin-related positions is due to the localised lattice rotation around the TD parallel to <011> axis. The starting points for the occurrence of new, recrystallized grains are the {110} <100> and {114}<221> components of the as-deformed microtexture inside the shear bands. As recovery and recrystallization proceed, the orientations of the primary nuclei systematically evolve to adopt simple boundary misorientation relations of similar to30degrees <111> type with respect to one of the two components of the deformed matrix. The results of the present study clarify the respective roles of all three basic mechanisms, i.e. oriented nucleation, growth (defined here as similar to30degrees <111>) and recrystallization twinning which are involved in the initial stages of recrystallization texture development in this low stacking fault energy alloy.
10.1016-S1359-6454(01)00411-6	-1		The diffuse X-ray scattering from a single crystal of Cu-24.3 at% Mn aged within the fcc phase at 770 K was measured at room temperature. Diffuse peaks were found at 2n(1)+0.2, 2n(2)+0.2, 0 and equivalent positions (n(1) and n(2) are integers) in reciprocal space. The Warren-Cowley short-range order parameters were derived from the separated short-range order scattering and used to generate the corresponding local atomic arrangements on a computer. The generated arrangements indicated that Mn atoms form clusters. A set of effective pair interaction energies obtained using an inverse Monte Carlo method showed that the interaction between the first nearest neighbors mainly affects the clustering of like atoms.
10.1016-S1359-6454(01)00437-2	6	grain; deformation; strain; strength; dislocation; cu-; tensile; size; ecap; grain size; sfe; ductility; hardening; high; stress	The structure, thermal stability and properties are investigated of a Cu-Cr-Zr alloy with ultra fine grains (UFG) of 160 nm diameter produced by severe plastic deformation through equal-channel angular pressing (ECAP). Special attention is paid to optimization of multi-functional thermal, electrical and mechanical properties of this alloy by aging after ECAP. Fatigue life and cyclic response under strain-controlled experiments are investigated aiming at clarification of mechanisms of plastic deformation and fracture in the precipitation hardened ECAP materials. It is shown that the precipitation strengthened UFG structure remains stable both under elevated temperatures as high as 500degreesC and under cyclic loading at room temperature. Substantial improvement of fatigue life is evidenced in comparison with conventional coarse-grain materials. The appearance of cyclic softening is noticed and its nature is discussed in terms of dislocation-particle interaction and possible dissolution of precipitates during fatigue.
10.1016-S1359-6454(02)00024-1	-1		The deformation behavior of a bulk Cu47Ti33Zr11Ni6Sn2Si1 metallic glass, fabricated by injection casting, has been characterized in the supercooled liquid region. The alloy deforms homogeneously and exhibits large elongation above the glass transition temperature at constant true strain rate below 1 x 10(-2)s(-1), but it shows a variation of the flow stress during deformation. The flow stress reaches a peak just after yielding and then decreases significantly with increasing strain. After the plateau level of remarkably low flow stress, it rises again and then the alloy finally fails in a brittle manner. DSC data and TEM observations for the tested alloy reveal that the alloy evolves to being crystallized during deformation. Nano-crystals are aggregated and the aggregates are aligned along the load direction. When the volume fraction of the crystalline phase is in the range up to 0.5, the nano-crystal aggregates effectively slide over each other, lowering the apparent stress level. However, as the amount of the crystalline phase further increases, the flow stress continuously increases. This behavior can be explained based on the volume-fraction rule between the crystalline phase and the amorphous phase.
10.1016-S1359-6454(02)00131-3	4	transformation; martensite; martensitic; phase; shape; beta; memory; shape memory; temperature; temperatures; martensitic transformation; gamma; transformation temperatures; effect; thermal	The advanced acoustic technique has been used to investigate the mobility of partial dislocations/intervariant boundaries in the beta(1)' martensite of a Cu-Zn-Al alloy subjected to the martensite stabilization and to the beta-phase ageing, suppressing the stabilization effect. The non-linear anelasticity has been studied for frequencies of about 100 kHz and strain amplitudes 2x10(-7)-2x10(-4) over the temperature range 300-8 K. Measurements at low temperatures, below approximately 70 K, allowed us to eliminate anelastic effects associated with the motion of quenched-in defects, which are 'frozen' for these temperatures, and to assess the intrinsic mobility of partial dislocation/intervariant boundaries. The results obtained for stabilized samples are compared with those for beta-phase aged samples, and with the previously reported data for the Cu-Al-Ni alloy, which is not prone to the stabilization at ambient temperatures. We suggest distinguishing mechanisms of stabilization according to their localization: a homogeneous and a heterogeneous component. Namely, short-range reordering occurring in the bulk of the crystal is responsible for the homogeneous component of the stabilization. The local rearrangement of the martensite structure in the vicinity of lattice defects (pinning of partial dislocations/intervariant boundaries by quenched-in defects and more intense than in the bulk localized reordering) is assumed to be responsible for the heterogeneous component of the stabilization process. The acoustic technique is shown to be able to distinguish and to study details of various effects associated with the heterogeneous and homogeneous changes in the structure of martensite, induced by the stabilization and different heat treatments.
10.1016-S1359-6454(02)00286-0	-1		Microstructures and phases stabilized at steady state by variable temperature ball milling of Cu50Ag50 powders are characterized using transmission and scanning transmission electron microscopy. Starting from chemically mixed and cold-worked powders obtained by room temperature milling, it is shown that, upon increasing the milling temperature, the material first decomposes into Cu-rich and Ag-rich solid solutions, and then recrystallizes. A similar sequence is observed during the static annealing of the solid solution precursor. In both cases, Cu-Ag nanocomposites are synthesized, at a scale of a few nanometers in the unrecrystallized state, and at a scale ranging from 30 nm after dynamic recrystallization to 75 nm after static recrystallization. These nanocomposites exhibit high hardness values, approaching 6 GPa. Interestingly enough, recrystallization leads to an increase in the hardness of these materials.
10.1016-S1359-6454(02)00351-8	6	grain; deformation; strain; strength; dislocation; cu-; tensile; size; ecap; grain size; sfe; ductility; hardening; high; stress	The effect of microstructure dimension delta on plasticity of high strength multi filamentary nanocomposite copper/niobium, wires was studied by nanoindentation. Two structures were tested: a Cu matrix containing Nb filaments and a Cu matrix containing Nb tubes filled with Cu. For delta > 10 mum, no size effect on the composite hardness is observed. In the 1-10 mum range, a strong increase in hardness indicates a change in plasticity mechanism, attributed to the classical Hall-Petch grain size strengthening. In the nanometre range, the hardness of the nanocomposite Cu/Nb regions exceeds that of nanocrystalline Cu or Nb, reaching 5.8 GPa for the finest conductors. The observed size effect on the plasticity of Cu/Nb nanostructures added to the dislocation barrier role of Cu/Nb interfaces confirms previous analyses based on the occurrence of a single dislocation regime at nanometre scale associated with impenetrable Cu/Nb interfaces.
10.1016-S1359-6454(03)00213-1	-1		Ion-beam mixing experiments show that amorphous phases are formed in the Cu70Ta30, Cu65Ta35, Cu60Ta40, and Cu50Ta50 multilayered samples, while a crystalline structure is retained in the Cu75Ta25 sample. These results suggest that the composition limit for forming an amorphous phase is around 30 at% Ta, which confirms the same value of 30 at% Ta predicted by recent atomistic modeling. For the metastable crystalline Cu75Ta25 phase, ab initio calculations identify its relatively stable structure to be L1(2) (fcc type) and determine some associated physical properties, which agree well with those derived from a proven realistic Cu-Ta potential through molecular dynamics simulations. Interestingly, an fcc Cu75Ta25 phase is indeed observed in ion-beam mixing experiments and its lattice constant determined by diffraction analysis matches well with those from theoretical calculations.
10.1016-S1359-6454(03)00325-2	-1		The diffusion induced grain boundary migration (DIGM) has been studied in the Cu-Cd system by exposing polycrystalline copper to Cd vapor. The temperature and time dependence of the rate of migration was measured in the range 340-480 degreesC. A parabolic migration behavior of the grain boundaries has been observed. The diffusivity, D(b)delta, was calculated from the growth rates and v/D(b)delta values obtained through concentration-distance profile at each temperature. It has been observed that the diffusion coefficient obtained experimentally during DIGM in the Cu-Cd system are 8 to 10 orders of magnitude higher than the corresponding volume diffusion coefficient. The activation energy for solute transport corresponds to that required for boundary diffusion in the Cu-Cd system.
10.1016-S1359-6454(03)00386-0	11	glass; bulk; metallic; bulk metallic; gfa; bmg; glassy; metallic glass; ability; bulk metallic glass; amorphous; addition; crystallization; mm; glass-forming	A group of Ti-Cu-Ni-Sn-Ta multicomponent alloys is prepared by copper mold casting and arc melting, respectively, in which nanostructured (or ultrafine-grained) matrix-dendrite composites can be obtained. With increasing Ti and Ta contents, the volume fraction of the dendritic phase increases. The grain size of the matrix phase depends on the preparation method, and is 30-70 nm for as-cast 2-3 mm diameter cylinders and about 100-200 nm for the as-arc melted samples. Compression test results indicate that fully nanostructured samples exhibit very high yield strength of 1800 MPa with a limited plastic strain of 1.4%. The nanostructured-dendrite composites exhibit high yield strengths of 1525-1755 MPa together with large plastic strains of 4.7-6.0%. The as-arc melted samples exhibit relatively lower yield strengths of 1037-1073 MPa with very large plastic strains of 16.5-17.9% because of the coarser grain size of the matrix. The large plasticity of the composites is attributed to the retardation of localized shear banding and the excessive deformation in the nanostructured matrix due to the in situ formed dendrites. The deformation and the fracture mechanisms of the nanostructure-dendrite composites are discussed based on fractography observations.
10.1016-S1359-6454(03)00435-X	6	grain; deformation; strain; strength; dislocation; cu-; tensile; size; ecap; grain size; sfe; ductility; hardening; high; stress	Temperature dependence of cyclic creep behavior has been studied using a Cu bicrystal containing dispersed SiO2 particles and a [011] 20degrees twist boundary. Failure occurred at shorter times with increasing temperature and stress amplitude. The fracture-mode of the bicrystals changed sharply from transgranular to intergranular at a certain critical stress amplitude. The brittle intergranular fracture that occurred below the critical stress amplitude caused discontinuous life shortening. The observed fracture-mode change at the critical stress amplitude is discussed in relation to grain-boundary sliding and grain-boundary cracking.
10.1016-S1359-6454(99)00260-8	-1		The segregation of impurities and subsequent embrittlement of grain boundaries in metallic alloys is an important and extensively studied phenomenon. X-ray compositional mapping in the analytical electron microscope (AEM) can identify, quantify and determine the distribution of the segregating elements. This approach offers the advantage over surface sensitive techniques that the sample does not have to be fractured, which permits a more complete description of the distribution of the segregant to be obtained. Optimization of a dedicated 300 kV, field-emission gun, ultra-high vacuum scanning transmission electron microscope allows the acquisition of compositional maps at high spatial resolution and high sensitivity. Bismuth segregation to grain boundaries in Cu has been mapped with a spatial resolution better than 2 nm and a sensitivity better than one tenth of a monolayer. Some of the advantages of mapping over traditional fixed probe or profile approaches have been demonstrated and a survey of segregation levels in a number of boundaries has illustrated the large degree of anisotropy in segregation levels beyond that revealed by surface techniques. (C) 1999 Acta Metallurgica Inc. Published by Elsevier Science Ltd. Ali rights reserved.
10.1016-S1359-6454(99)00374-2	4	transformation; martensite; martensitic; phase; shape; beta; memory; shape memory; temperature; temperatures; martensitic transformation; gamma; transformation temperatures; effect; thermal	Investigations of the ultrasonic strain amplitude-dependent internal friction (ADIF) and of the influence of ultrasonic vibrations on the macroplastic strain (the acoustoplastic effect) have been performed in situ during deformation of quenched Cu-Al-Ni single crystals in the Pi martensitic phase. The effect of the macroscopic plastic strain rate on the ADIF and acoustoplastic effect as well as the kinetics of the acoustoplastic effect has been studied. The results of in situ ADIF measurements are compared with data on the ADIF temperature dependence. Observed regularities are attributed to differences in the mechanisms of the macroplastic deformation of the martensitic phase, related to the motion of intervariant interfaces, and of the reversible anelastic strain, which, at ultrasonic frequencies and moderate strain amplitudes, is largely due to the oscillatory motion of the partial disiocations. The conclusion has been drawn that the dynamics of partial dislocations at temperatures of 210-300 K is to a great extent determined by their interaction with atmospheres of mobile pinners with saturated density. Simultaneous measurements of the ADIF and acoustoplastic effect allows the conclusion that, for high oscillatory strain amplitudes, the breakthrough of partial dislocations beyond the mobile atmospheres of pinners initiates the step-like accumulation of the macroplastic strain due to the motion of intervariant boundaries.
10.1016-S1359-6454(99)00467-X	-1		From a Cu-O.O65mass%B solid solution alloy, bicrystals having [001]-twist grain boundaries with various misorientation angles were prepared by the Bridgman method. Cu bicrystals containing B2O3 particles were made from the bicrystals by internal oxidation treatment. The Cu-B2O3 bicrystals were tensile tested at high temperatures, where B2O3 particles become liquid. The amount of grain-boundary sliding was measured from the amount of shear deformation of the liquid B2O3 particles on a sliding grain boundary. Shear deformation of Voids where the B2O3 particles was embedded was also utilized to measure the amount of grain-boundary sliding. The temperature and misorientation-angle dependence of the grain-boundary sliding is discussed for the Cu-B2O3 bicrystals. Since the liquid B2O3 particles easily deform at high temperatures, the measured amount of grain-boundary sliding is considered to reflect the inherent nature of the Cu [001]-twist grain boundaries. Using the present method of measurements, up to 2 mu m grain-boundary sliding can be measured with an accuracy of about 0.1 mu m.
10.1016-S1359-6462(01)01119-8	6	grain; deformation; strain; strength; dislocation; cu-; tensile; size; ecap; grain size; sfe; ductility; hardening; high; stress	The Cu-40%Zn alloy is a classic two-phase material exhibiting superplasticity at elevated temperatures. This report demonstrates that the application of severe plastic deformation at a temperature associated with a phase transformation leads to grain refinement in the alloy and the development of a superplastic ductility at a high strain rate and relatively low temperature.
10.1016-S1359-6462(01)01165-4	-1		Bicrystals of Cu-8%Sn grown from the melt to make a Sigma = 5 (031)[001] symmetrical tilt boundary were found to be very difficult to crack by dynamic embrittlement, even along the fast-diffusion direction, in contrast with earlier results on bicrystals made by diffusion bonding that contained particles in the boundary. This has implications for the role of particles and the tendency for cracking in low-Sigma boundaries. (C) 2001 Published by Elsevier Science Ltd. on behalf of Acta Materialia Inc.
10.1016-S1359-6462(02)00560-2	11	glass; bulk; metallic; bulk metallic; gfa; bmg; glassy; metallic glass; ability; bulk metallic glass; amorphous; addition; crystallization; mm; glass-forming	The mechanical properties of Cu47Ti34Zr11Ni8, Cu47Ti33Zr11Ni8Fe1, and Cu47Ti33Zr11Ni8Si1 bulk metallic glasses prepared by copper mold casting are investigated. Room temperature compression tests reveal fracture strengths above 2000 MPa, Young's moduli around 100 GPa and elastic strains slightly exceeding 2.0%. Only Cu47Ti33Zr11Ni8Si1 exhibits distinct plastic strain due to a unique composite microstructure with in situ formed nanoscale precipitates in the glassy matrix.
10.1016-S1359-6462(03)00018-6	-1		Formation of the nanoicosahedral particles having a size ranged,from 3 to 10 nm is observed in Cu55Zr30Ti10Pd5 glassy alloy in the initial stage of the devitrification process. The structure changes on,heating were studied by X-ray diffraction, transmission electron microscopy differential scanning and isothermal calorimetry..
10.1016-S1359-6462(03)00140-4	-1		Atomic force microscopic observations of interfacial structures of twinned gamma'(1) martensite plates in single crystals of Cu-14wt%Al-3.4wt%Ni alloy revealed the presence of either side-plate extensions or well-defined twin facets at the martensite/parent phase interface. These results indicate that there are alternative means of accommodating micro-scale mismatch strains at the interface.
10.1016-S1359-6462(03)00162-3	-1		The microstructure of Cu-6.1 at%Ag thin wire cold drawn to a true strain of eta = 9.6 has been investigated by a three-dimensional atom probe. Substantial mixing progressed and the Ag concentration of Ag filament decreased to only 22 at% at eta = 9.6. This is believed to be a part of the reasons for the low electrical conductivity of the severely cold drawn composite wire.
10.1016-S1468-6996(03)00056-1	-1		The structure and primary devitrification process of the melt-spun Cu-60(Zr or Hf)(30)Ti-10 alloys were investigated. It was confirmed that the compositional segregation in the diameter range of 5-10 nm exists in the as-quenched state. The nanocrystalline particles with cubic structure are observed in the glassy matrix in the high-resolution transmission electron microscopy images, of which size is corresponding to the scale of compositional segregation. Small-angle X-ray scattering measurement also indicates the development of nanoscale inhomogeneity with the same size as that of nanocrystalline particles. The nanocrystalline region has high Cu content. In contrast, Zr or Hf and Ti elements are enriched in the glassy region. These results are recognized as the formation of novel structure consisting of the glassy and nanocrystalline phases. It is suggested that the precipitation of bcc CuZr phase as a primary crystallization phase proceeds in the glassy phase remaining the nanocrystalline phase in the Cu-Zr-Ti alloy. Meanwhile, the glassy and nanocrystalline phases are transformed to an orthorhombic Cu8Hf3 phase at the initial crystallization stage in the Cu-Hf-Ti alloy. These differences of crystallization process are consistent with the results of thermodynamic and kinetic analyses of the transformation mode.
10.1016-S1872-1508(07)60050-3	-1		Based on the random solution model and stoichiometric intermetallic compound Gibbs free energy model, the driving forces for the crystallization from the undercooled liquid of Cu-Zr binary alloys were evaluated by using Turnbull and Thompson-Spaepen (TS) approximate equations, respectively. Using Davies-Uhlmann kinetic formulations within the frame of continuous nucleation theory (CNT), two groups of time-temperature transformation (TTT) curves of eight compositions of the binary system were calculated, and thereby the corresponding critical cooling rates were obtained. It is shown that both groups of the calculated values for the glass-forming ability (GFA) are in good agreement with the experimental data. The critical cooling rates evaluated by using TS equation are in good agreement with the experimental data compared with that evaluated by using Tumbull equation.
10.1016-s1875-5372(14)60124-7	11	glass; bulk; metallic; bulk metallic; gfa; bmg; glassy; metallic glass; ability; bulk metallic glass; amorphous; addition; crystallization; mm; glass-forming	Cu46Zr46Al8 bulk metallic glass (BMG) was prepared by low purity sponge zirconium instead of high purity crystal bar zirconium, and via the microalloying of adding a small amount of yttrium. The results show that the glass forming ability (GFA) and the thermal stability of the Cu46Zr46Al8 alloy are improved by yttrium addition. When the addition amount of Y is 2at% and 3at%, the enhancement of GFA is most significant. The compressive fracture strength of Y microalloyed BMG is more than 2 GPa, which is much higher than that of BMG alloy produced with high purity raw materials, but its plasticity deteriorates obviously.
10.1017-S0263034616000732	-1		LASER induced breakdown spectroscopy (LIBS) has been used for the quantitative analysis of Cu-Ni alloy of known composition (75% Cu, 25% Ni) using the one line calibration free-LIBS (OLCF-LIBS), self-calibration-LIBS (SC-LIBS), calibration free LIBS (CF-LIBS), time of flight-mass spectroscopy (TOF-MS), energy dispersive X-ray spectroscopy (EDX) and X-ray fluorescence spectroscopy (XRF). For the LIBS-based studies, the plasma was generated by focusing the beam of a Q-switched Nd:YAG laser (532 nm, pulse energy about 200 mJ, 5 ns pulse duration) while the sample was placed in air at an atmospheric pressure. Plasma temperature about (9500 +/- 300) K was calculated by the Boltzmann plot method using the neutral lines of Cu and Ni whereas the electron number density was calculated (2.0 +/- 0.5) x 10(16) cm(-3) from the Stark broadening of an isolated Cu line as well as using the relative intensities of the neutral and singly ionized optically thin lines in the Saha-Boltzmann equation. The elemental compositions determined by different LIBS methods and standard techniques are; OLCF-LIBS (69% Cu and 31% Ni), SC-LIBS (72% Cu and 28% Ni), CF-LIBS (74% Cu and 26% Ni), TOF (74% Cu and 26% Ni), EDX (75% Cu and 24.5% Ni), XRF (73% Cu and 24.7% Ni), and LA-TOF (74% Cu and 26% Ni). It is demonstrated that the CF-LIBS method gives compositions comparable with that determined by LA-TOF, EDX, or XRF, which is also in agreement with the certified reported composition.
10.1017-s0263034618000137	-1		The effect of magnetic field on the plasma parameters and surface modification of Cu-alloy has been investigated. For this purpose, we have employed Nd: YAG laser at various irradiances ranging from 1.9 to 5 GW/cm(2) to irradiate Cu-alloy under 5 torr pressure of argon, neon, and helium. The evaluated values of excitation temperature (T-exc) and electron number density (n(e)) of Cu-alloy plasma explored by laser-induced breakdown spectroscopy technique are higher in the presence of 1.1 Tesla magnetic field as compared with field-free case. It is true at all irradiances as well as under all environmental conditions. It is also found that trends of both T-exc and n(e) are increasing with increasing laser irradiance from 1.9 to 4.4 GW/cm(2). For the highest used irradiance 5 GW/cm(2), the decrease in both parameters is observed. The analytically calculated values of thermal beta, directional beta, confinement radius, and diffusion time for laser-irradiated Cu-alloy plasma confirm the validity of magnetic confinement. Scanning electron microscope analysis is utilized to study the surface modifications of laser-irradiated Cu samples and reveals the formation of islands, craters, cones, and droplets. The finer-scale surface structures are grown in case of magnetic. It is also revealed T-exc and n(e) play a substantial part in the growth of surface structures on Cu-alloy.
10.1017-S1431927615015263	2	corrosion; surface; film; electrochemical; films; spectroscopy; layer; current; solution; potential; resistance; composition; x-ray; ions; showed	Archaeological materials present unique records on natural processes allowing the study of long-term material behaviors such as structural modifications and degradation mechanisms. The present work is focused on the chemical and microstructural characterization of four prehistoric arsenical copper artifacts. These artifacts were characterized by micro-energy dispersive X-ray fluorescence spectrometry, optical microscopy, scanning electron microscopy with X-ray microanalysis, micro-X-ray diffraction and synchrotron radiation micro-X-ray diffraction. Cu3As is the expected intermetallic arsenide in arsenical copper alloys, reported in the literature as exhibiting a hexagonal crystallographic structure. However, a cubic Cu3As phase was identified by X-ray diffraction in all of our analyzed archaeological artifacts, while the hexagonal Cu3As phase was clearly identified only in the artifact with higher arsenic content. Occurrence of the cubic arsenide in these particular objects, suggests that it was precipitated due to long-term aging at room temperature, which points to the need of a redefinition of the Cu-As equilibrium phase constitution. These results highlight the importance of understanding the impact of structural aging for the assessment of original properties of archaeological arsenical copper artifacts, such as hardness or color.
10.1021-acs.jpcc.1c05664	-1		Continued efforts to transition toward renewable energy sources have spurred tremendous research into the discovery of near-infrared gap semiconductors. Here we describe the optical properties and electronic structure of copper zinc sulfide nanocrystals, with copper mole fractions as high as x(Cu) = 0.18. Copper zinc sulfide is shown to be a near-infrared gap semiconductor that exists in both zinc blende and wurtzite forms, similar to ZnS. The bandgap is shown to vary over 3.45-2.15 eV as the copper mole fraction is changed from 0.01 to 0.18. We find that the valence band of CuZnS nanocrystals has a significant tendency for hole localization, similar to other highly mismatched alloys. Further, our ultrafast studies are consistent with rapid (450 +/- 60 fs) removal of conduction band electrons and subsequent defect emission over 4.3 ns.
10.1021-acs.jpcc.1c05978	-1		Since physical chemistry data were not available for a Cu-Al-Au ternary system, physical chemistry analysis of this system was carried out experimentally using scanning electron microscopy with energy-dispersive spectroscopy (SEM-EDX) and differential thermal analysis (DTA) measurements. The hardness, microhardness, and electrical conductivity as additional data of the investigated alloys in the Cu-Al-Au system were determined too. The shape memory effect, pseudoelasticity, biocompatibility, good resistance to corrosion and fatigue, and resistance to bending enable the application of Cu-Al- Au alloys to a large number of medical products, such as orthopedic and dental implants, products related to cardiovascular surgery, surgical instruments, etc. SEM-EDX analysis confirmed the existence of solid solutions based on copper, aluminum, and gold (Cu, Al, Au), beta, epsilon, and gamma phases, as well as intermetallic compounds AuAl2, Al2Cu, and AlCu. The characteristic temperatures of the phase transformation were determined by DTA. The results of hardness and microhardness showed that the highest values were measured in alloys whose composition included the gamma phase.
10.1021-acs.jpcc.3c05344	-1		The Cu-S alloy is of great scientific importance due to its wide range of technological applications, including Cu-S antifluorite crystals exhibiting topological states. To gain insights into the sulfur-copper interaction, a simplified model of sulfur adsorption in copper is commonly used, particularly in surface reconstructions like the (root 7x root 7)R19.1 degrees phase. However, determining the optimal structural model for this type of reconstruction has been a persistent challenge. Among the various models proposed to explain the reconstruction, Foss and Prince models have gained greater acceptance. In our comprehensive study, we employed a comparative approach utilizing angle-resolved photoemission spectroscopy, scanning tunneling microscopy, and density functional theory calculations. Our objective was to investigate the band structure and local density of states of this reconstruction resulting from sulfur segregation on the Cu(111) surface, with the aim of assessing the compatibility of the experimental results with the two leading models. Remarkably, our analysis unveiled intriguing localization effects within the bulk resonances and distinctive surface bands originating from the copper-sulfur cluster present in both models. Through careful examination of electronic dispersion and the local density of states, we successfully distinguished between the models and determined which one better aligned with our experimental data.
10.1021-acs.jpcc.3c05505	14	strength; properties; conductivity; electrical; mechanical; cu-; grain; mpa; electrical conductivity; aging; precipitation; phase; mechanical properties; tensile; phases	The timeless allure of Cu-Sn-based intermetallics, commonly known as bronze, stems from their remarkable versatility across a wide range of applications. When used as coatings on stainless steel, Cu-Sn brings forth a host of advantages including enhanced aesthetics, corrosion resistance, low surface tension, weldability, and ductility. However, the electroplating of Cu-Sn onto stainless steel by using acidic baths proves to be a costly affair due to the inherent instability of the acidic solution. Moreover, the short lifespan of the bath necessitates the use of expensive additives. In this study, we present an innovative approach- a stable and cost-effective basic pyrophosphate-based electrolyte bath, to deposit Cu, Sn, and Cu-Sn coatings. Through X-ray diffraction analysis, the Cu-Sn coatings on stainless steel are found to predominantly consist of Cu13.7Sn and Cu3Sn phases, with a minor presence of elemental Sn. Impressively, the Cu-Sn bath exhibits a high current efficiency of 92% and demonstrates exceptional long-term stability, maintaining its integrity for over a year even when exposed to ambient air. To gain deeper insights into the nucleation and growth mechanisms, we conduct a comprehensive investigation employing cyclic voltammetric and chronoamperometric studies. By employing the Scharifker-Hills model, we meticulously analyze the nucleation and growth steps, while further analysis of the cyclic voltammetric results allows us to unravel the intricacies of diffusion kinetics during deposition.
10.1021-acs.jpcc.7b02068	-1		A univalent copper hyper-stoichiometric stannoidite Cu8+xFe3-xSn2S12 with 0 <= x <= 0.5 has been synthesized using mechanical alloying followed by spark plasma sintering. The X-ray diffraction analysis combined with Fe-57 and Sn-119 Mossbauer investigations has allowed the charge distribution of the cationic species on the various sites to be established and suggests the possibility of a small tin deficiency. The transport properties show a remarkable crossover from a semiconducting to a metal-like behavior as the copper content increases from x = 0 to x = 0.5, whereas correlatively the Seebeck coefficient decreases moderately, with S values ranging from 310 to 100 mu V/K. The thermal conductivity decreases as the temperature increases showing low values at high temperature, far below those reported in related stannite materials. The investigation of the thermoelectric properties shows that the ZT figure of merit is dramatically enhanced by the copper hyper-stoichiometry by a factor of 5 going from 0.07 for x = 0 to 0.35 for x = 0.5 at 630 K. This thermoelectric behavior is interpreted on the basis of a model involving the Cu-S framework as the conducting electronic network where the Fe2+/Fe3+ species play the role of hole reservoir.
10.1021-acs.nanolett.2c03512	-1		Spatiotemporal pattern formation is dynamic self-organiza-tion widely observed in nature and drives various functions. Among these functions, chirality plays a central role. The relationship between dynamic self-organization and chirality has been an open question; therefore, the production of chiral nanomaterials by dynamic self-organization has not been achieved. Here, we show that the confinement of a two-dimensional spatiotemporal micropattern via the electrodeposition of a binary Cu alloy into a nanopore induces mirror symmetry breaking to produce a helical nanostructure of the noble-metal component although it is still not yet possible to control the handedness at this stage. This result suggests that spatiotemporal symmetry breaking functions as a mirror symmetry breaking if cylindrical pores are given as the boundary condition. This study can be a model system of how spatiotemporal symmetry breaking plays a role in mirror symmetry breaking, and it proposes a new approach to producing helical nanomaterials through dynamic self-organization.
10.1021-acs.nanolett.5b03483	4	transformation; martensite; martensitic; phase; shape; beta; memory; shape memory; temperature; temperatures; martensitic transformation; gamma; transformation temperatures; effect; thermal	Bent Cu-Al-Ni nanopillars (diameters 90-750 nm) show a shape memory effect, SME, for diameters D > 300 nm. The SME and the associated twinning are located in a small deformed section of the nanopillar. Thick nanopillars (D > 300 nm) transform to austenite under heating, including the deformed region. Thin nanopillars (D < 130 nm) do not twin but generate highly disordered sequences of stacking faults in the deformed region. No SME occurs and heating converts only the undeformed regions into austenite. The defect-rich, deformed region remains in the martensite phase even after prolonged heating in the stability field of austenite. A complex mixture of twins and stacking faults was found for diameters 130 nm < D < 300 nm. The size effect of the SME in Cu-Al-Ni nanopillars consists of an approximately linear reduction of the SME between 300 and 130 nm when the SME completely vanishes for smaller diameters.
10.1021-acsaem.1c00559	-1		Constantan (Cu-Ni alloy) is widely used in the field of thermocouples due to its excellent thermoelectric and mechanical properties. To broaden the application area, the intrinsically high thermal conductivity is intentionally suppressed with the aim to increase the thermoelectric figure-of-merit (ZT) and eventually the energy conversion efficiency. All-scale hierarchical architectures including the point defect, second phase, nanocomposite, and micropore are realized in Cu-Ni-based alloys, leading to the significant reduction in thermal conductivity from 18.14 to 3.23 W m(-1) K-1 at 773 K. Therefore, the thermoelectric properties have been improved with the ZT being up to 0.23 at 773 K. The present work demonstrates a promising and general strategy to enhance the thermoelectric performance of materials with ultrahigh electrical and thermal conductivity.
10.1021-acsaem.2c00404	-1		A Cu-Ni-based alloy with a high power factor is a commercially utilized metallic thermocouple material. However, the high thermal conductivity has been a major limitation to achieving thermoelectric performance in semiconductor materials. Herein, this work presents a 76.1% reduced thermal conductivity (similar to 7.7 W m(-1) K-1) in Cu70Ni30, which is one of the lowest reported values in the literature. Such suppression of thermal conductivity can be attributed to the varied frequency phonon scattering by the interfacial potential barrier, built from micron-scale defects formed via sintering melt-spun ribbons. However, the defects simultaneously reduce the charge carrier concentration, mobility, and thus the electrical conductivity. The lowest thermal conductivity leads to the highest zT and ZT(avg) in the sample sintered at 673 K under 15 MPa. The values are 0.24 (@573 K) and 0.15 (323-573 K), respectively, which are 130.3 and 140.0% higher than the values of the pristine counterpart. Our work demonstrates that improved thermoelectric performance in Cu-Ni-based alloys can be obtained by creating various interfacial defects even at micron scales, which paves the way to suppress thermal conductivity largely in metallic thermoelectric materials via melt-spinning (MS) and spark plasma sintering (SPS) synthesis.
10.1021-acsami.0c01100	-1		Although various processes for metal printing at the micro- and mesoscale have been demonstrated, printing functional devices such as thermocouples, thermopiles, and heat flux sensors that function based on interfaces between an alloy and another alloy/metal demands processes for printing alloys. Furthermore, a high-quality and crystalline alloy is required for acceptable function of these devices. This article reports for the first time co-electrodeposition-based printing of single-phase solid solution nanocrystalline copper/nickel (Cu/Ni) alloy with various controllable compositions (Cu100Ni0 to Cu19Ni81) from a single electrolyte. The printed alloy is nanocrystalline (<35 nm), continuous, and dense with no apparent porosity, with remarkable mechanical and magnetic properties, without any postprocessing annealing such as heat treatment. In addition, a functional thermocouple fabricated using this process is demonstrated. Such a process can not only be used for fabrication of functional devices, it may also facilitate fundamental studies on alloys by printing a continuous library of alloy composition for material characterization.
10.1021-acsami.6b13956	-1		Polyvinylidene fluoride (PVDF)-copolymer conductive composites containing 40 vol % copper (Cu) and tin (Sn) fillers are prepared by injection molding. Postmolding thermal annealing is found to increase the electrical conductivity of the composites by an order of magnitude. The volume ratio between Cu and Sn is found to have a significant effect on filler distribution but a weaker effect on electrical conductivity compared to the annealing conditions. Synchrotron X-ray tomography is used to visualize and quantitatively analyze the morphology and distribution of the filler particles, indicating that higher conductivity can be, attributed to better dispersion of the low-melting-point Sn filler, which provides better interparticle contact in the Cu network.
10.1021-acsami.7b05308	-1		Printable and flexible Cu-Ag alloy electrodes with high conductivity and ultrahigh oxidation resistance have been successfully fabricated by using a newly developed Cu-Ag hybrid ink and a simple fabrication process consisting of low-temperature precuring followed by rapid photonic sintering (LTRS). A special Ag nanoparticle shell on a Cu core structure is first created in situ by low-temperature precuring. An instantaneous photonic sintering can induce rapid mutual dissolution between the Cu core and the Ag nanoparticle shell so that core shell structures consisting of a Cu-rich phase in the core arid a Ag-rich phase in the shell (Cu-Ag alloy) can be obtained on flexible substrates. The resulting Cu-Ag alloy electrode has high conductivity (3.4 mu Omega.cm) and ultrahigh oxidation.resistance even up to 180 degrees C in an air atmosphere; this approach shows huge potential and is a tempting prospect for the fabrication of highly reliable and cost-effective printed electronic devices.
10.1021-acsami.8b01205	-1		A gradient nano-grained (GNG) surface layer is fabricated on a commercial-purity Cu sample, in which a significant reduction in the coefficient of friction and the wear loss is obtained compared to the coarse-grained and the nano grained counterparts. A novel mild ploughing mechanism without subsurface damage has been identified in the GNG sample, giving rise to a much reduced wear rate. Sliding induced surface deformation brings about the unique inhomogeneous substructure in the GNG Cu: the topmost layer persists with nanograins without being oxidized, underneath which deformation is well accommodated by grain coarsening adjacent to the dynamic recrystallization layer. Both subsurface structural evolution and stress field model confirm that sliding-induced strain localization is suppressed, which is responsible for the superior friction and wear behaviors of the GNG Cu.
10.1021-acsami.8b04049	-1		A 3D porous Cu current collector used in Li-ion batteries can improve the cycling performance of Sn anodes with high specific capacity because of the accommodation of large volume expansion by the pores. However, the pure Cu ligament is too soft to endure enough stress from volume expansion, and then it leads to the fast fade of capacity because of the formation of cracks or the collapse of the 3D porous structure. In this study, a novel micro-nano 3D hierarchical porous Cu-based composite current collector with enhanced ligaments has been fabricated by one-step dealloying of the Cu-34Zn-6Al (wt%) precursor and subsequent heat treatment. The pore and microstructure evolutions during dealloying and heat treatment have been studied by X-ray diffraction, scanning electron microscopy, and transmission electron microscopy. To confirm the validity of the 3D porous Cu/beta/gamma composite current collector, Sn has been directly electroless plated on it in comparison with the porous pure Cu and the common Cu foil. It is found that the Sn-coated 3D hierarchical porous Cu/beta/gamma composite current collector with higher hardness shows significantly improved cycling stability compared with the Sn-coated 3D porous Cu current collector and the planar copper foil.
10.1021-acsami.9b10630	-1		Ga and Ga-based alloys have received significant attention for applications in the liquid state and also for their potential as a bonding material in microelectronic assemblies. This study investigates the phase stability of the CuGa(2 )phase as a product of the interfacial reaction between liquid Ga and Cu-10Ni substrates at room temperature. In the binary Ga-Cu system, CuGa2 is decomposed into liquid Ga and Cu9Ga4 as the temperature increases to around 260 degrees C, which prevents the widespread application of this alloy. In contrast to CuGa2 grown from a pure Cu substrate, CuGa2 from the Cu-10Ni substrate shows an increase in the decomposition temperature during heating from 25 to 300 degrees C. According to our first-principle calculations, there is only a minor difference in the total free energy between Ni solute at the Cu sublattice and the Ga sublattice in the tetragonal CuGa2 crystal structure. This result indicates that both of the sublattices can accommodate the dilute Ni solute with comparable probability. Regardless of the sublattice where the Ni impurities are located, the presence of diluted Ni in the matrix stabilizes the CuGa2 system by inducing some localized Ni(3)d states at energy levels near the Fermi level. It is also shown that the formation of Cu antisite defects, which also stabilizes CuGa2, is preferable if the CuGa2 matrix is grown on a Nicontaining substrate.
10.1021-acsanm.0c01879	-1		The present investigation is aimed to find a thread between various surface textures of polycrystalline Cu-Ni alloys, in cold-rolled and annealed conditions, and the nature of graphene, grown by the chemical vapor deposition (CVD) method, on these substrates. High-quality graphene grown on Cu-Ni alloys was transferred to various nanostructures, such as CuO nanorods and carbon nanotubes, for field emission application. In this work, Cu-Ni (100Cu-0Ni, 84.65Cu-15.35Ni, 72.6Cu-27.4Ni, and 63Cu-37Ni) alloy buttons were prepared by arc melting, and texture in the samples were engineered by cold rolling (plastic deformation) and annealing (recrystallization) processes. Study of surface texture by X-ray method demonstrates characteristically different deformation and recrystallization texture components, compared to conventional rolling and annealing textures. The evolution of texture has been explained based on the effects of surface friction, shear stress, and addition of Ni. Unusual appearance of {111} orientations, though less in volume, after annealing at 1000 degrees C, was observed in Cu-Ni alloys through the suppression of cube texture component. The underlying deformation and recrystallization mechanisms are explained through the changes in strain hardening, extended recovery, and continuous recrystallization effects. The effects of Ni content are correlated with the number of graphene layers, while an increase in the fraction of {111} orientations could be linked with defect density in graphene layers. Results of the present study will be motivating for selection of various polycrystalline Cu-Ni alloys, with different surface textures, for controlling quality of graphene, synthesized by the chemical vapor deposition method.
10.1021-acsanm.9b01199	-1		Sintering is an essential step to obtain bulk components from aluminum powders, which enables powder metallurgy-based fabrication methods such as additive manufacturing technologies. Copper (Cu) can form alloys with aluminum (Al), and the introduction of Cu particles can be used to enhance the sintering behavior of Al alloys. Good dispersion of Cu particles is critical in such approaches, which, however, may be difficult to achieve. In this study, Cu nanoparticles (NPs) were synthesized and attached to the surface of AI powder particles with the assistance of a polydopamine (PDA) coating. This composite powder showed enhanced sintering behavior, which may be attributed to the Al-Cu alloy phase(s) formed at grain boundaries. The improved electrical and mechanical properties of the sintered material demonstrate that this combined Cu-NP deposition and PDA coating approach is a good candidate method for the manufacture of Al powders with enhanced sinterability.
10.1021-acsomega.1c07368	7	irradiation; shear; grain; ta; deformation; size; radiation; voids; nanocrystalline; simulations; similar; void; temperature; irradiated; boundaries	Deformation processing of immiscible systems is observed to disrupt thermodynamic equilibrium, often resulting in nonequilibrium microstructures. The microstructural changes including nanostructuring, hierarchical distribution of phases, localized solute supersaturation, and oxygen ingress result from high-strain extended deformation, causing a significant change in mechanical properties. Because of the dynamic evolution of the material under large strain shear load, a detailed understanding of the transformation pathway has not been established. Additionally, the influence of these microstructural changes on mechanical properties is also not well characterized. Here, an immiscible Cu-4 at. % Nb alloy is subjected to a high-strain shear deformation (similar to 200); the deformation-induced changes in the morphology, crystal structure, and composition of Cu and Nb phases as a function of total strain are characterized using transmission electron microscopy and atom probe tomography. Furthermore, a multimodal experiment-guided computational approach is used to depict the initiation of deformation by an increase in misorientation boundaries by crystal plasticity-based grain misorientation modeling (strain similar to 0.6). Then, co-deformation and nanolamination of Cu and Nb are envisaged by a finite element method-based computational fluid dynamic model with strain ranging from 10 to 200. Finally, the experimentally observed amorphization of the severely sheared supersaturated Cu-Nb-O phase was validated using the first principle-based simulation using density functional theory while highlighting the influence of oxygen ingress during deformation. Furthermore, the nanocrystalline microstructure shows a >2-fold increase in hardness and compressive yield strength of the alloy, elucidating the potential of deformation processing to obtain high-strength low-alloyed metals. Our approach presents a step-by-step evolution of a microstructure in an immiscible alloy undergoing severe shear deformation, which is broadly applicable to materials processing based on friction stir, extrusion, rolling, and surface shear deformation under wear and can be directly applied to understanding material behavior during these processes.
10.1021-acsomega.2c07278	-1		In powder metallurgymaterials, sintered density in Cu-Alalloyplays a critical role in detecting mechanical properties. Experimentalmeasurement of this property is costly and time-consuming. In thisstudy, adaptive boosting decision tree, support vector regression, k-nearest neighbors, extreme gradient boosting, and fourmultilayer perceptron (MLP) models tuned by resilient backpropagation,Levenberg-Marquardt (LM), scaled conjugate gradient, and Bayesianregularization were employed for predicting powder densification throughsintering. Yield strength, Young's modulus, volume variationcaused by the phase transformation, hardness, liquid volume, liquidustemperature, the solubility ratio among the liquid phase and the solidphase, sintered temperature, solidus temperature, sintered atmosphere,holding time, compaction pressure, particle size, and specific shapefactor were regarded as the input parameters of the suggested models.The cross plot, error distribution curve, and cumulative frequencydiagram as graphical tools and average percent relative error (APRE),average absolute percent relative error (AAPRE), root mean squareerror (RMSE), standard deviation (SD), and coefficient of correlation(R) as the statistical evaluations were utilizedto estimate the models' accuracy. All of the developed modelswere compared with preexisting approaches, and the results exhibitedthat the developed models in the present work are more precise andvalid than the existing ones. The designed MLP-LM model was foundto be the most precise approach with AAPRE = 1.292%, APRE = -0.032%,SD = 0.020, RMSE = 0.016, and R = 0.989. Lately,outlier detection was applied performing the leverage technique todetect the suspected data points. The outlier detection discoveredthat few points are located out of the applicability domain of theproposed MLP-LM model.
10.1021-acsomega.3c07561	-1		The mechanical properties of CuTi alloys have been characterized extensively through experimental studies. However, a detailed understanding of why the strength of Cu increases after a small fraction of Ti atoms are added to the alloy is still missing. In this work, we address this question using density functional theory (DFT) and molecular dynamics (MD) simulations with the modified embedded atom method (MEAM) interatomic potentials. First, we performed calculations of the uniaxial tension deformations of small bicrystalline Cu cells using DFT static simulations. We then carried out uniaxial tension deformations on much larger bicrystalline and polycrystalline Cu cells by using MEAM MD simulations. In bicrystalline Cu, the inclusion of Ti increases the grain boundary separation energy and the maximum tensile stress. The DFT calculations demonstrate that the increase in the tensile stress can be attributed to an increase in the local charge density arising from Ti. MEAM simulations in larger bicrystalline systems have shown that increasing the Ti concentration decreases the density of the stacking faults. This observation is enhanced in polycrystalline Cu, where the addition of Ti atoms, even at concentrations as low as 1.5 atomic (at.) %, increases the yield strength and elastic modulus of the material compared to pure Cu. Under uniaxial tensile loading, the addition of small amounts of Ti hinders the formation of partial Shockley dislocations in the grain boundaries of Cu, leading to a reduced level of local deformation. These results shed light on the role of Ti in determining the mechanical properties of polycrystalline Cu and enable the engineering of grain boundaries and the inclusion of Ti to improve degradation resistance.
10.1021-acsomega.9b00569	2	corrosion; surface; film; electrochemical; films; spectroscopy; layer; current; solution; potential; resistance; composition; x-ray; ions; showed	The long-term interaction between Cu-based alloys and environmental species gives rise to the formation of different and sometimes unusual compounds (i.e., the patina) with distinctive chemical and structural features as a function of the peculiar characteristics of the context. In this paper, we describe some representative case studies concerning degraded bronze Roman valuable or common use objects, and we show that an attentive study at a microscale level, as for forensic analysis, allows one to understand the chemical processes that underlie the formation of the surface alteration products. The achieved information describe fragments of chemical life and disclose the complex chemical changes suffered by the artifacts, allowing one to write their chemical biography. This challenging approach expands the panorama of available information and demonstrates that it is possible to reconstruct the different modes through which the bronze surfaces and interfaces have interacted with environmental species, organic matter, and microorganisms, opening up a new possibility to describe complex environmental chemical stories, in certain cases interrelated.
10.1021-acssuschemeng.2c00771	-1		This study outlines a novel and sustainableelectrodeposition-redox replacement (EDRR) method to produceCu/Zn alloys using a simulated hydrometallurgical Zn solutioncontaining 200 ppm Cu, 65 g/L Zn, and 10 g/L H2SO4. Theresults indicate that by tailoring the EDRR parameters, likedeposition time, replacement time, and agitation conditions, Cu/Zn alloys with controllable properties including chemicalcomposition, microstructures, colorations, and crystalline phasescan be readily obtained. Scanning electron microscopy (SEM)analysis shows that coherent Cu/Znfilms grow from separatenanoscale particles produced during the initial EDRR cycles.Furthermore, the corrosion performance of the prepared Cu/Znfilms is tunable by changing the crystalline phases through thevariation of operating conditions. For example, deposits containing Zn-rich phases (CuZn5,Cu5Zn8) obtained with short redoxreplacement times without agitation resulted in relatively poor corrosion resistance. In contrast, Cu-rich phases (Cu0.75Zn0.25,Cu0.85Zn0.15) with enhanced corrosion performance were achieved with prolonged redox replacement times and/or the application ofmagnetic stirring. Unlike traditional electrodeposition, the EDRR method does not involve any complexing agents and the currentlyunderutilized hydrometallurgical solutions were used as potential raw materials. Overall, the study suggests the EDRR method as apromising approach to achieve sustainable manufacturing of Cu/Zn alloys and an improved circular economy of metals.
10.1021-am100186n	2	corrosion; surface; film; electrochemical; films; spectroscopy; layer; current; solution; potential; resistance; composition; x-ray; ions; showed	An environmentally benign approach to surface modification was developed to impart copper surface with enhanced resistance to corrosion, bacterial adhesion and biocorrosion. Oxidative graft polymerization of 2,2'-bithiophene from the copper surface with self-assembled 2,2'-bithiophene monolayer, and subsequent reduction of silver ions to silver nanoparticles (Ag NPs) on the surface, give rise to a homogeneous bithiophene polymer (PBT) film with densely coupled Ag NPs on the copper surface (Cu-g-PBT-Ag NP surface). The immobilized Ag NPs were found to significantly inhibit bacterial adhesion and enhance the antibacterial properties of the PBT modified copper surface. The corrosion inhibition performance of the functionalized copper substrates was evaluated by Tafel polarization curves and electrochemical impedance spectroscopy. Arising from the chemical affinity of thiols for the noble and coinage metals, the copper surface functionalized with both PBT brushes and Ag NPs also exhibits long-term stability, and is thus potentially useful for combating the combined problems of corrosion and biocorrosion in harsh marine and aquatic environments.
10.1021-am4010946	-1		We report the improved thermal stability of carbon alloyed Cu0.6Te0.4 for resistive memory applications. Copper-tellurium-based memory cells show enhanced switching behavior, but the complex sequence of phase transformations upon annealing is disadvantageous for integration in a device. We show that addition of about 40 at% carbon to the Cu-telluride layer results in an amorphous material up to 360 degrees C. This material was then integrated in a TiN/Cu0.6Te0.4-C/Al2O3/Si resistive memory cell, and compared to pure Cu0.6Te0.4. Very attractive endurance (up to 1 x 10(3) cycles) and retention properties (up to 1 x 10(4) s at 85 degrees C) are observed. The enhanced thermal stability and good switching behavior make this material a promising candidate for integration in memory devices.
10.1021-am5026853	-1		We report the continuous one-step synthesis of bimetallic copper-nickel nanostructured coatings by deposition and sintering of metal nanoparticles produced as an aerosol using a flame driven high temperature reducing jet (HTRJ) process. The HTRJ process allows gas-phase (aerosol) formation of metal nanoparticles from low-cost metal salt precursors. These can be collected as discrete powders for subsequent use in formulating conductive inks or for other applications. However, direct deposition of nanoparticles to form coatings allows measurements of electrical conductivity of films of deposited nanoparticles as a function of composition and sintering temperature, without actually formulating and printing inks. This is the approach taken here for the purpose of screening nanoparticle compositions quickly. We characterized the microstructure and composition of both nanopowders and films and found that their composition consistently matched the ratio of metals in the precursor solution. The electrical conductivity was highest (similar to 10(4) S/m) for films with 60:40 and 40:60 copper-to-nickel mass ratios. These films maintained their conductivity during extended storage (1 month) under ambient conditions. The oxidation resistance and high conductivity observed here suggest that 60:40 and 40:60 Cu:Ni nanoparticles have promise as lower cost replacements for silver nanoparticles in conductive ink formulations.
10.1021-cm501109r	-1		The atomic layer deposition (ALD) of Cu metal films was carried out by a two-step process with Cu(OCHMeCH2NMe2)(2) and BH3(NHMe2) on Ru substrates and by a three-step process employing Cu(OCHMeCH2NMe2)(2), formic acid, and BH3(NHMe2) on Pd and Pt substrates. The two-step process demonstrated self-limited ALD growth at 150 degrees C with Cu(OCHMeCH2NMe2)(2) and BH3(NHMe2) pulse lengths of >= 3.0 and >= 1.0 s, respectively. An ALD window was observed between 130 and 160 degrees C, with a growth rate of about 0.13 angstrom/cycle. Atomic force microscopy (AFM) and scanning electron microscopy (SEM) revealed rough Cu films that likely originate from the Cu nanoparticle seed layer. The Cu films exhibited poor electrical conductivity because of their nanoparticulate natures. The three-step process showed self-limited ALD growth on Pd and Pt at 150 degrees C with Cu(OCHMeCH2NMe2)(2), formic acid, and BH3(NHMe2) pulse lengths of >= 3.0, >= 0.3, and >= 1.0 s, respectively. ALD windows were observed between 135 and 165 degrees C on both Pd and Pt, with growth rates of 0.20 angstrom/cyde on both substrates. Plots of film thickness versus number of cycles showed linear growth behavior on Pd with a growth rate of 0.20 angstrom/cycle up to 2000 cycles. By contrast, a similar plot for growth on Pt revealed nonlinear growth behavior, with a growth rate of about 0.4 angstrom/cycle up to 500 cycles, and then a growth rate of about 0.03 angstrom/cycle between 500 and 2000 cycles. The large difference in growth behavior between Pd and Pt substrates is proposed to occur by formation of a Cu/Pd alloy film and continuous catalytic decomposition of the BH3(NHMe2) by the surface Pd sites. By contrast, there is much less surface Pt in the growing Cu film, and catalytic decomposition of BH3(NHMe2) by the diminishing surface Pt as the Cu film grows leads to a decreased growth rate beyond 500 cycles. X-ray photoelectron spectroscopy reveals the formation of high purity Cu metal for all depositions, with low levels of C, N, O, and B. The Cu films on Pd and Pt showed smooth, continuous films at all thicknesses and had low electrical resistivities.
10.1021-ic5014945	-1		The thermoelectric properties of Zn-, In-, and I-doped Cu1.7Bi4.Se-7(8) pavonite homologues were investigated in the temperature range from 300 to 560 K. On the basis of the comprehensive structural analysis using Rietveld refinement of synchrotron radiation diffraction for Cux+yBi5-ySe8 compounds with the inherently disordered crystallographic sites, we demonstrate a doping strategy that provides a simultaneous control for enhanced electronic transport properties by the optimization of carrier concentration and exceptionally low lattice thermal conductivity by the formation of point defects. Substituted Zn or In ions on Cu site was found to be an effective phonon scattering center as well as an electron donor, while doping on Bi site showed a moderate effect for phonon scattering. In addition, we achieved largely enhanced power factor in small amount of In doping on Cu site by increased electrical conductivity and moderately decreased Seebeck coefficient. Coupled with a low lattice thermal conductivity originated from intensified point defect phonon scattering by substituted In ions with host Cu ions, a thermoelectric figure of merit ZT of 0.24 at 560 K for Cu1.6915In0.0085Bi4.7Se8 was achieved, yielding 30% enhancement compared with that of a pristine Cu1.7Bi4.7Se8 at the same temperature.
10.1021-jp052509s	-1		Assisted by ab initio calculations, an n-body Cu-Re potential is first constructed for the equilibrium-immiscible Cu-Re system under the second moment approximation of a tight-binding scheme. The proven realistic Cu-Re potential is then applied to perform the molecular dynamics simulations using the Cu-Re sandwich model. The simulations reveal that the interfacial free energy stored in the Cu/Re interfaces plays an important role in facilitating the spontaneous solid-state amorphization and that the amorphous interlayer grows in a layer-by-layer mode featuring an asymmetric behavior, i.e., the growth of the amorphous interlayer advances faster toward the Cu lattice than toward the Re direction. It is also found that with increasing the simulation time, the growth speed of the amorphous interlayer gradually slows down and eventually becomes zero when the interlayer reaches a thickness of about 1.47 nm. Interestingly, according to a recently proposed thermodynamic and kinetic model, the maximum thickness of the growing amorphous layer is limited by the available interfacial free energy and in the Cu-Re system, it is estimated to be around 1.35 nm, which is comparable with that observed from the simulations.
10.1021-jp100690r	-1		An n-body potential is constructed for the Cu-Ti-Hf ternary metal system under a recently proposed formalism named long-range empirical potential. Applying the proven relevant Cu-Ti-Hf potential, molecular dynamics simulations are carried out using solid solution model to compare the relative stability of the crystalline solid solution versus its disordered counterpart as a function of solute concentration. The simulation results not only reveal that the physical origin of the crystal-to-amorphous transition is the collapse of the crystalline lattice, while the solute atoms exceed the critical value, but also predict a region in the composition triangle energetically favored for the Cu-Ti-Hf ternary metallic glass formation. Interestingly, the prediction directly from the n-body potential is supported by the experimental observations and is in accordance with the so-called structural difference rule.
10.1021-jp200082e	13	clusters; atomic; glass; atoms; composition; dynamics; metallic; icosahedral; glasses; simulations; molecular; cu-zr; molecular dynamics; metallic glasses; structural	For the Cu-Zr-Ni system, an interatomic potential was constructed under the newly proposed formulism named smoothed and long-range second-moment approximation of tight-binding. Applying the constructed potential, molecular dynamics simulations were carried out to compare the relative stability of crystalline solid solution versus its disordered counterpart. Simulations not only reveal that the origin of metallic glass formation is the crystalline lattice collapsing while the solute concentrations exceed critical values, but also determine a quadrilateral region, within which the metallic glass formation is energetically favored. Moreover, the energy differences between the crystalline solid solutions and the disordered states were considered as the driving force for amorphizational and were computed by molecular static calculations. The calculation results located an optimized composition area with the driving force much greater than those outside. In addition, the alloys around the composition of Cu16Zr60Ni24 were identified to have maximum driving force, and the atomic configurations were also analysed by the Voronoi tessellation method.
10.1021-jp305954q	-1		We have prepared Cu80Co20 powders by high-energy ball milling under ambient atmosphere. The evolutions of both the microstructure and the magnetic properties have been investigated as a function of milling time. 3D-focused ion beam was used for microstructural characterization for low milling time (1.5 h). For higher milling time (20 h) atom probe tomography was used to investigate at the atomic scale the elemental distribution of chemical species. In the first steps of milling, the powder presents a ferromagnetic signal due to the presence of micrometric cobalt particles. After 20 h of milling, the powder is composed of CoO particles with diameter around 10-50 nm surrounded by a copper rich matrix (Cu-84 +/- 2%, Co-16 +/- 2%) and a few cobalt-rich nanoclusters. For this milling time, a typical giant magnetoresistive effect is observed. A positive magnetoresistive effect is also observed at 5 K under low magnetic fields, which is related to the presence of Co oxides clusters. After a heat treatment at 450 degrees C for 1 h, the precipitation of Co into the copper rich matrix is observed, the enhanced, and the positive magnetoresistive effect disappears. giant magnetoresistive effect is enhanced, and the positive magnetoresistive effect disappears.
10.1021-jp5114637	-1		The surface free energies of solidvapor interfaces and grain boundaries were measured in CuFe solid solutions. The solidvapor interface measurements were performed by the direct in situ method in a temperature range from 900 to 1080 degrees C in a dry hydrogen atmosphere. The solid solutions contained 0.045 at. % Fe, 0.25 at. % Fe, 0.40 at. % Fe, 0.58 at. % Fe, and 0.74 at. % Fe. The grain boundary free energy was obtained by measuring the dihedral angles at the top of the thermal grooves. The isotherms of the surface free energy demonstrated an unusual behavior with a maximum. The surface free energy in Cu-based solid solutions was analyzed. We analyzed both our own and published data. Data were obtained via direct measurements at high (premelting) temperatures. The analysis of CuMe systems (Me decreases the surface free energy of copper) showed a strong linear correlation between the logarithm of the surface activity ln(-dFS/dXMe)X?0 and the difference of molar areas of a solute and copper ?Am (=AmMe AmCu). Iron-based systems also fit the correlation. The approximating line intersected the difference molar area axis at the positive value.
10.1021-jp5120064	13	clusters; atomic; glass; atoms; composition; dynamics; metallic; icosahedral; glasses; simulations; molecular; cu-zr; molecular dynamics; metallic glasses; structural	This study combines the molecular dynamics (MD) simulations and first-principles approach to explain the experimental observation that the best glass formers of Cu-Zr bulk metallic glasses (BMGs) have the compositions Cu50Zr50 and Cu64Zr36. These two best glass formers are first calculated to be most abundantly composed of Cu6Zr7 and Cu8Zr5 icosahedral clusters when compared in the compositional range of CuxZr(100-x) (45 <= x <= 70), and then these two icosahedral clusters are calculated to have the lowest formation energy among the icosahedral clusters CuxZr13-x (3 <= x <= 10), as well as possessing some characteristics in electronic structure and chemical hardness. Through understanding the properties of specific icosahedral clusters in metallic glasses, the structural and energetic contribution to the glass-forming ability are systematically discussed.
10.1021-jz3014425	-1		Metallic glasses have been established to have unique properties such as ductility, toughness, and soft magnetism with promising engineering applications. However, the glass-forming ability (GFA) has not been sufficient to synthesize the bulk metallic glasses (BMGs) required for many engineering applications. Attempts to develop the understanding of the GFA required to predict the optimum alloys have not yet been proven successful. We develop here a computational model based on molecular dynamics simulations that explains the dramatic change of GFA with alloying small amounts of Al into Cu-Zr. We find that the high GFA to form BMGs depends on a combination of three factors, (a) a low thermodynamic driving force for crystallization, (b) a high melt viscosity, and (c) large ratios of icosahedral structures in the liquid phase. These computational methods to predict these factors that suppress formation of crystal nuclei and slow the dynamic motions in the liquids are practical for in silico prediction of new alloys with optimal GFA.
10.1023-A-1004770519874	-1		CuCr alloys with varying Cr content were sputter deposited on polyimide films, and the metal/polyimide films were maintained under 350 degrees C/N-2 environment up to 10 hours for the reliability measurements. The Cr contents of the alloy layer prepared were 0, 8.5, 17, 25, 34, and 100 atomic %, respectively. Before exposures to 350 degrees C, the peel strength increased proportionally with the Cr content in the alloy layer up to 17 atomic % and saturated. The failure occurred inside polyimide near the metal/polyimide interface by the cohesive failure mode except for the specimen with no Cr. After exposures to 350 degrees C, the peel strength dropped for all the specimens, but most drastically for the specimens with 8.5% Cr which failed along the Cr-oxide/polyimide interface by the interfacial failure mode. Through AES and XPS analyses, it was shown that the decrease of the peel strength during the heat treatment was primarily caused by the formation of brittle Cr2O3 at the metal/polyimide interface, which was accompanied by the reduction of carbidic bonds responsible for the good adhesion. (C) 2000 Kluwer Academic Publishers.
10.1023-A-1010663417536	2	corrosion; surface; film; electrochemical; films; spectroscopy; layer; current; solution; potential; resistance; composition; x-ray; ions; showed	Patinae on Cu-base alloys have been characterized by means of GDOS, SEM, XRD and AFM. The effect of a protective coating was tested in aggressive artificial solutions. Patinae and the bulk of several metal Panic objects were also examined. The GDOS results combined with SEM capabilities allow exhaustive investigation of composition, element distribution and microstructure of modified surface in modern bronzes exposed to accelerated ageing tests as well as in ancient bronzes. The SEM data of the patina thickness agree with the GDOS data. The XRD and SEM investigations allow an exhaustive characterization of corrosion products. Corrosion growth in its Parry stages determines the effectiveness of the patina's protective role and the AFM is a promising technique for investigating this.
10.1023-A-1011541021610	-1		A modified first-order kinetic law which takes into account defect decay during an ordering process was employed to predict the short-range-order kinetics of a quenched and a quenched-deformed Cu-5 at% Zn alloy, in conjunction with experiments performed by isothermal calorimetry. The effective activation energy of point defect migration and its temperature dependence strongly suggest the contribution of bound vacancies to the ordering process. An estimate of 91.2 kJ mol(-1) was made for the activation energy of solute- vacancy migration by applying an effective rate constant, a value in very good agreement with that obtained from previous non-isothermal experiments. The isothermal curves were utilized to determine the ordering energy: w=-2.90 kJ mol(-1). In conjunction, a parametric study of the defect sink density was performed in order to assess its influence on the calculated isothermal curve profiles.
10.1023-A-1013861003079	2	corrosion; surface; film; electrochemical; films; spectroscopy; layer; current; solution; potential; resistance; composition; x-ray; ions; showed	The initial stages of the formation of phase layers at a copper electrode in solutions containing sulfate fate and sulfite ions are investigated by the method of quartz microweighing. It is found that the growth of a layer in acidic and neutral solutions proceeds in conformity with a parabolic law. The composition of the surface layer is investigated by x-ray photoelectron spectroscopy. The main component of the layer is found to be Cu2O. In sulfite-containing solutions, an insoluble sulfite compound of Cu+ is also included in the layer.
10.1023-A-1014969618372	4	transformation; martensite; martensitic; phase; shape; beta; memory; shape memory; temperature; temperatures; martensitic transformation; gamma; transformation temperatures; effect; thermal	By means of differential scanning calorimetry (DSC) the precipitation process from a supersaturated solid solution of Cu-0.65 at% Co 0.33 at% Si (Cu-1 at% Co2Si) was investigated. On the basis of enthalpimetric calculations it was found that the decomposition begins with cobalt precipitation. Clustering of atoms of cobalt initiates the precipitation of silicon, and particles of the stoichiometric CO2Si composition are finally formed. Kinetic parameters were obtained by a convolution method based on the Mehl-Johnson-Avrami formalism, Their values are all in agreement with the experimentally observed behavior displayed by DSC traces. Decay kinetics of cobalt and silicon matrix during simulated isothermal calculations using DSC data reveals good agreement with similar computed results reported in literature. Precipitate dissolution obeys quite well to a three-dimensional diffusion kinetic law previously developed.
10.1023-A-1025021521945	-1		A method for the determination of the density of electromagnetically levitated metallic liquids has been developed. This method employs an enlarged beam of parallel laser light to produce a shadow image of the sample. The shadow is recorded by a digital CCD-camera, and the images are analyzed using an edge detection algorithm. The circumference is fitted by Legendre polynomials that can be used for calculations of the volume of the sample. The method has been tested successfully on various alloys of copper-nickel (NixCuy), as well as on the pure elements, Cu and Ni. Densities were measured for each sample at different temperatures below and above the melting point, and a linear behavior was observed. At the melting point the densities for copper and nickel were 7.9 and 7.93 g . cm(-3), respectively. For T = 1270 degreesC liquid copper has a density of 7.75 g . cm(-3) which strongly increases up to roughly 8.1 g . cm(-3) if a small amount (10-40 at%) of nickel is added to the system. For nickel concentrations larger than 50 at% the density remains nearly constant.
10.1023-B-JACH.0000016616.78823.2b	2	corrosion; surface; film; electrochemical; films; spectroscopy; layer; current; solution; potential; resistance; composition; x-ray; ions; showed	To improve the mechanical properties of electrodeposited copper, a new bath was developed for the codeposition of copper and platinum. A pyrophosphate bath employing chloroplatinic acid as a source of platinum was investigated at current densities ranging from 1 to 4 A dm(-2) and temperatures from 20 to 60degreesC. Bright, shiny and crack-free deposits were obtained at low current densities (i.e., 1-2 A dm(-2)). The amount of platinum observed in the deposits was found to increase with the current density and bath temperature. The Knoop hardness was found to increase with platinum content in the deposits. Corrosion rates measured in solutions of NaCl were found to decrease with platinum content. Deposits containing up to 3.9 wt% of platinum can be obtained by electrodeposition. As compared to electrodeposited copper from the acid bath, the Cu-Pt deposits exhibited a 17% increase in Knoop hardness and a 21% increase in corrosion resistance.
10.1023-B-JACH.0000035612.66363.a3	2	corrosion; surface; film; electrochemical; films; spectroscopy; layer; current; solution; potential; resistance; composition; x-ray; ions; showed	The electrochemical behaviour of copper-nickel alloys with different Ni content (5-65%) in sulphate solutions of pH 12 was investigated. The effects of temperature, immersion time, and concentration of sulphate ions were also studied. Different electrochemical methods such as open-circuit potential measurements, polarization techniques and electrochemical impedance spectroscopy (EIS) were used. Potentiodynamic measurements reveal that the increase in nickel content increases the corrosion rate of the alloy in sulphate solution linearly. Nevertheless, an increase in the nickel content along with increase in immersion time improves the stability of the Cu-Ni alloys due to the formation of a stable passive film. An equivalent circuit model for the electrode/electrolyte interface under different conditions was proposed. The experimental impedance data were fitted to theoretical data according to the proposed model. The relevance of the model to the corrosion/passivation phenomena occurring at the electrode/solution interface was discussed.
10.1023-B-JMSC.0000025831.58057.52	-1		The mechanical response of in-situ copper-chromium composite was modelled using a deformation mechanism map approach . The stresses in each phase were predicted as a function of temperature and strain rate. From this the ratio of phase stresses, and hence the degree of load transfer, was obtained. The extent of load transfer and the predicted deformation modes of the two phases were then related to the expected failure mechanisms of the composite. Three modes of composite failure were predicted. Copper-chromium in-situ composites, and pure copper, were produced by a casting and swaging route. The mechanical properties were then characterised experimentally by tensile testing. Mechanical tests confirmed that the composite showed significantly higher strength than the unreinforced material. The observed failure modes of the composite were compared with the predictions. (C) 2004 Kluwer Academic Publishers.
10.1023-B-OXID.0000025336.56015.a2	-1		The effect of impurities on the formation of the inner porous layer in the Cu2O scale during copper oxidation was examined using 99.99% (4N), 99.9999% (6N) and floating-zone-refined (FZR, > 99.9999%) copper specimens at 800degreesC. Oxidation for 240 min shows that an inner porous layer was formed in the Cu2O scale near the Cu2O/Cu interface for 4N copper, but not for 6N and FZR copper. The results support that the inner porous layer in the oxide scale is related to impurities from the metal base.
10.1038-nature19313	-1		Nanocrystalline metals, with a mean grain size of less than 100 nanometres, have greater room-temperature strength than their coarse-grained equivalents, in part owing to a large reduction in grain size(1). However, this high strength generally comes with substantial losses in other mechanical properties, such as creep resistance, which limits their practical utility; for example, creep rates in nanocrystalline copper are about four orders of magnitude higher than those in typical coarse-grained copper(2,3). The degradation of creep resistance in nanocrystalline materials is in part due to an increase in the volume fraction of grain boundaries, which lack long-range crystalline order and lead to processes such as diffusional creep, sliding and rotation(3). Here we show that nanocrystalline copper-tantalum alloys possess an unprecedented combination of properties: high strength combined with extremely high-temperature creep resistance, while maintaining mechanical and thermal stability. Precursory work on this family of immiscible alloys has previously highlighted their thermo-mechanical stability and strength(4,5), which has motivated their study under more extreme conditions, such as creep. We find a steady-state creep rate of less than 10(-6) per second-six to eight orders of magnitude lower than most nanocrystalline metals-at various temperatures between 0.5 and 0.64 times the melting temperature of the matrix (1,356 kelvin) under an applied stress ranging from 0.85 per cent to 1.2 per cent of the shear modulus. The unusual combination of properties in our nanocrystalline alloy is achieved via a processing route that creates distinct nanoclusters of atoms that pin grain boundaries within the alloy. This pinning improves the kinetic stability of the grains by increasing the energy barrier for grain-boundary sliding and rotation and by inhibiting grain coarsening, under extremely long-term creep conditions. Our processing approach should enable the development of microstructurally stable structural alloys with high strength and creep resistance for various high-temperature applications, including in the aerospace, naval, civilian infrastructure and energy sectors.
10.1038-s41467-024-45732-y	-1		Additive manufacturing (AM), known as 3D printing, enables rapid fabrication of geometrically complex copper (Cu) components for electrical conduction and heat management applications. However, pure Cu or Cu alloys produced by 3D printing often suffer from either low strength or low conductivity at room and elevated temperatures. Here, we demonstrate a design strategy for 3D printing of high strength, high conductivity Cu by uniformly dispersing a minor portion of lanthanum hexaboride (LaB6) nanoparticles in pure Cu through laser powder bed fusion (L-PBF). We show that trace additions of LaB6 to pure Cu results in an improved L-PBF processability, an enhanced strength, an improved thermal stability, all whilst maintaining a high conductivity. The presented strategy could expand the applicability of 3D printed Cu components to more demanding conditions where high strength, high conductivity and thermal stability are required. Copper produced by laser additive manufacturing often faces challenges with either low strength or low conductivity. Here, the authors present a design strategy to introduce uniformly dispersed nanoprecipitates during solidification, enhancing the strength while maintaining high conductivity.
10.1038-s41524-019-0227-7	-1		Traditional strategies for designing new materials with targeted property including methods such as trial and error, and experiences of domain experts, are time and cost consuming. In the present study, we propose a machine learning design system involving three features of machine learning modeling, compositional design and property prediction, which can accelerate the discovery of new materials. We demonstrate better efficiency of on a rapid compositional design of high-performance copper alloys with a targeted ultimate tensile strength of 600-950 MPa and an electrical conductivity of 50.0% international annealed copper standard. There exists a good consistency between the predicted and measured values for three alloys from literatures and two newly made alloys with designed compositions. Our results provide a new recipe to realize the property-oriented compositional design for high-performance complex alloys via machine learning.
10.1038-s41586-019-1783-1	-1		Additive manufacturing, often known as three-dimensional (3D) printing, is a process in which a part is built layer-by-layer and is a promising approach for creating components close to their final (net) shape. This process is challenging the dominance of conventional manufacturing processes for products with high complexity and low material waste(1). Titanium alloys made by additive manufacturing have been used in applications in various industries. However, the intrinsic high cooling rates and high thermal gradient of the fusion-based metal additive manufacturing process often leads to a very fine microstructure and a tendency towards almost exclusively columnar grains, particularly in titanium-based alloys(1). (Columnar grains in additively manufactured titanium components can result in anisotropic mechanical properties and are therefore undesirable(2).) Attemptsto optimize the processing parameters of additive manufacturing have shown that it is difficult to alter the conditions to promote equiaxed growth of titaniumgrains(3). In contrast with other common engineering alloys such as aluminium, there is no commercial grain refiner for titanium that is able to effectively refine the microstructure. To address this challenge, here we report on the development of titanium-copper alloys that have a high constitutional supercooling capacity as a result of partitioning of the alloying element during solidification, which can override the negative effect of a high thermal gradient in the laser-melted region during additive manufacturing. Without any special process control or additional treatment, our as-printed titanium-copper alloy specimens have a fully equiaxed fine-grained microstructure. They also display promising mechanical properties, such as high yield strength and uniform elongation, compared to conventional alloys under similar processing conditions, owing to the formation of an ultrafine eutectoid microstructure that appears as a result of exploiting the high cooling rates and multiple thermal cycles of the manufacturing process. We anticipate that this approach will be applicable to other eutectoid-forming alloy systems, and that it will have applications in the aerospace and biomedical industries.
10.1038-s41597-023-02411-9	-1		This article presents a collection of data on approximately 150 copper-based alloys. The data compilation is based on articles published since 1993 and consists of about 1830 records. Each record contains a unique set of descriptors, such as composition and processing route, and targets, including properties such as hardness, yield strength, ultimate tensile strength, and electrical conductivity. The dataset includes information on the composition in mass percent of 20 alloying elements, and hundreds of temperature-time thermal treatments and thermomechanical conditions. The database is continually updated and hosted on an open data repository. Some of the data are presented graphically in the article to aid interpretation. This study intends to promote the identification of more sustainable alternatives to Cu-Be alloys, which is particularly relevant in developing non-toxic and environmentally-friendly alloys.
10.1038-s41598-019-48941-4	2	corrosion; surface; film; electrochemical; films; spectroscopy; layer; current; solution; potential; resistance; composition; x-ray; ions; showed	A collection of ancient Roman orichalcum coins, i.e., a copper-zinc alloy, minted under the reigns from Caesar to Domitianus, have been characterised using scanning electron microscopy (SEM-EDS) and electron microprobe analysis (EMPA). We studied, for the first time, coins emitted by Romans after the reforms of Augustus (23 B.C.) and Nero (63-64 A.D). These coins, consisting of asses, sestertii, dupondii and semisses, were analysed using non- and invasive analyses, aiming to explore microstructure, corrosive process and to acquire quantitative chemical analysis. The results revealed that the coins are characterized by porous external layers, which are affected by dezincification and decuprification processes. As pictured by the X-ray maps, the elemental distribution of Cu and Zn shows patterns of depletion that in some cases penetrate in deep up to 1 mm. The composition of the un-corroded nucleus is a Cu-Zn alloy containing up to 30% of Zn, typical of coins produced via cementation process.
10.1038-s41598-020-74903-2	-1		The immiscible alloy Cu-Ta has the potential for enhanced mechanical performance in applications as a functional coating. To establish baseline mechanical properties, four Cu-Ta films were co-sputtered at the temperatures 23, 400, 600, and 800 degrees C and tested with nanoindentation at strain rates 5 x 10(-3) s(-1) to 10 s(-1). Each film had a unique microstructure morphology. The hardness and elastic modulus of the four films were insensitive to strain rate changes. Instead, the measured properties were spatially dependent, particularly in the 600 and 800 degrees C films. In those two films, there is a bimodal deformation behavior due to Cu-agglomeration under protruding grains and planar Ta-rich regions. Increasing the indentation depth revealed shear band suppression which is related to a homogenous distribution of flow stresses for all four microstructure morphologies. Finally, the Cu-Ta hardness appeared to follow a rule-of-mixtures when compared to extrapolated data of Cu and Ta monolithic films.
10.1038-s41598-020-78772-7	-1		An experimental method for alloy development that allows to systematically scan multicomponent alloy systems is presented using the Cu-Ga-Sn system as an example. Rods with homogeneous concentration distribution of different initial compositions are annealed in a steep temperature gradient with temperatures in the range from above liquidus to below solidus temperature. During resolidification of the initially formed mushy-zone, a continuously varying composition over the length of the rods develops. Further concentration gradients of the alloying elements are generated during subsequent directional solidification. The graded samples are evaluated for different properties. Vickers hardness as a function of composition was measured along the length of the samples to get first information on the mechanical behavior of bulk samples. The melting range of selected compositions (cylindrical disks of 1 mm thickness cut out of the rods) was determined by differential scanning calorimetry and compared to liquidus temperatures extrapolated from the binary systems with a fitting method and the Calphad method. With the procedure introduced here, it is possible to determine several alloy properties over an extended composition range of a multicomponent system with significantly reduced experimental effort.
10.1038-s41598-024-73926-3	-1		In this work, we investigated the effects of alloying elements on plastic deformation and microstructure evolution in polycrystalline copper (Cu) and Cu alloyed with 1 wt%\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$\%$$\end{document} lead (Cu-1%\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$\%$$\end{document}Pb). These materials were selected due to the size mismatch between Cu and Pb, with the latter forming precipitates at grain boundaries. Multi-modal characterization techniques, including neutron diffraction, electron backscatter diffraction (EBSD), and transmission electron microscopy (TEM), along with finite element simulations were employed to study the deformation behavior across multiple length scales. While both Cu and Cu-1%\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$\%$$\end{document}Pb exhibited similar macroscale response and final deformation textures, both dislocation line profile analysis and TEM revealed increased dislocation density in deformed Cu-1%\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$\%$$\end{document}Pb specimens. The presence of lead precipitates also significantly affected local plastic deformation during compression, with their influence diminishing with increasing strain. These results demonstrate the complex relationships between alloying elements, plastic deformation, microstructural evolution, and material behavior under load. The insights gained from this multi-scale and multi-technique approach contribute to the fundamental understanding of microstructural evolution in immiscible alloys and are valuable for tailoring the properties of structural materials for specific engineering applications.
10.1038-s41598-025-97335-2	14	strength; properties; conductivity; electrical; mechanical; cu-; grain; mpa; electrical conductivity; aging; precipitation; phase; mechanical properties; tensile; phases	In this study, a Cu-Sn superhydrophobic coating was fabricated on the surface of X70 steel via the electrodeposition method, resulting in an optimal contact angle of 164.2 +/- 1.2 degrees. Compared to the X70 substrate, the Cu-Sn coating exhibits superior corrosion resistance. In a 3.5 wt% NaCl solution, the polarization resistance (Rp) is 71,037 ohmcm2, approximately 48 times higher than the substrate; the corrosion current (Icorr) is 2.23 x 10- 7 A/cm2, roughly two orders of magnitude lower than that of the substrate. This enhancement is attributed to the addition of Sn, which combines with Cu to form a Cu-Sn alloy with a micro-nano structure, effectively improving the hydrophobicity and corrosion resistance of the coating. However, excessive SnSO4 can hinder the formation of the micro-nano structure, leading to aggregation on the coating surface. In addition, the coating exhibits excellent self-cleaning properties and mechanical stability. After undergoing rigorous mechanical stability tests, including tape peeling, sandpaper abrasion, water drop impact, and sand erosion, the contact angle remains above 155 degrees. These results are significant for addressing the issue of long-term durability and stability of superhydrophobic coatings in industrial applications and provide new prospects for the deposition of metals or alloys.
10.1038-srep09550	6	grain; deformation; strain; strength; dislocation; cu-; tensile; size; ecap; grain size; sfe; ductility; hardening; high; stress	In this study, the concept of twinning induced plasticity (TWIP) alloys'' is broadened, and the underlying intrinsic microscopic mechanisms of the general TWIP effect are intensively explored. For the first aspect, TWIP copper alloys'' was proposed following the concept of TWIP steels'', as they share essentially the same strengthening and toughening mechanisms. For the second aspect, three intrinsic features of twinning: i.e. dynamic development'', planarity'', as well as orientation selectivity'' were derived from the detailed exploration of the deformation behavior in TWIP copper alloys. These features can be considered the microscopic essences of the general TWIP effect''. Moreover, the effective cooperation between deformation twinning and dislocation slipping in TWIP copper alloys leads to a desirable tendency: the synchronous improvement of strength and plasticity (SISP). This breakthrough against the traditional trade-off relationship, achieved by the general TWIP effect'', may provide useful strategies for designing high-performance engineering materials.
10.1038-srep31101	-1		We report results of our experimental and theoretical studies on the oxidation of Cu-Au alloy surfaces, viz., Cu3Au(111), CuAu(111), and Au3Cu(111), using hyperthermal O-2 molecular beam (HOMB). We observed strong Au segregation to the top layer of the corresponding clean (111) surfaces. This forms a protective layer that hinders further oxidation into the bulk. The higher the concentration of Au in the protective layer formed, the higher the protective efficacy. As a result, of the three Cu-Au surfaces studied, Au3Cu(111) is the most stable against dissociative adsorption of O2, even with HOMB. We also found that this protective property breaks down for oxidations occurring at temperatures above 300 K.
10.1039-c3ra42504e	-1		Electrochemically driven intercalation of Cu into Te was used to prepare Cu2 xTe (0.2 < x <= 2) thin films and accurately control the composition of the resulting samples. A thorough theoretical analysis of the system using density functional theory (DFT) calculations showed that in the absence of external electric fields the driving forces for Cu atoms to move into the subsurface layers of the Te electrodes depend on the surface coverage of copper atoms. The Cu atoms tend to preferentially occupy the subsurface layers in the telluride films. The effective electric charge on Cu atoms inside the Te-electrodes is positive. These effective charge differences with respect to pure Cu and pure Te are only 0.2 e(-). Scanning Kelvin probe (SKP), atomic force microscopy (AFM) and electrochemical techniques were used to characterise the surface status of the obtained samples. Both, DFT-calculated work function differences and the SKP-measured contact potential differences (CPD) change non-linearly with the variation of the film composition. Interfacial (solid/liquid) properties evaluated using electrochemical impedance spectroscopy depend on the nominal composition of the samples and display an abrupt change that correlates with a large change in the work function and CPD. While the proposed electrochemical synthetic route can efficiently and accurately control the composition of the Cu2-xTe thin films, SKP-measurements performed under close to ambient conditions in combination with DFT calculations can provide a promising tool to link fundamental surface properties and parameters which define the interface between solids and liquids.
10.1039-c3ta11457k	-1		Pavonite homologues, Cux+yBi5-ySe8 (1.2 <= x <= 1.5, 0.1 <= y <= 0.4), in a polycrystalline bulk form have been synthesized using a conventional solid state sintering technique. Their thermal and electronic transport properties were evaluated for mid-temperature thermoelectric power generation applications. Structural complexity, based on unique substitutional and interstitial Cu atoms in the structure, makes this system attractive as an intrinsic low thermal conductivity material; also the band structure calculations revealed that interstitial Cu atoms generate n-type carrier conduction. Room temperature lattice thermal conductivities ranging between 0.41 W m(-1) K-1 and 0.55 W m(-1) K-1 were found for Cux+yBi5-ySe8; these values are comparable to those of the state-of-the-art low lattice thermal conductivity systems. These extremely low thermal conductivities combined with the power factors result in the highest ZT = 0.27 at 560 K for Cu1.9Bi4.6Se8.
10.1039-c4ra04295f	-1		In this paper, a computational thermodynamic approach was used to design the compositions of bulk metallic glass composites. This approach indicates that both the liquidus temperature and the solidification temperature range of the primary phase of a Cu-Zr-Ti-Si alloy system increase with the addition of silicon. With the aid of the calculation, the crystal-embedded Cu-based bulk metallic glass composites have been fabricated successfully. The as-cast composites were characterized by X-ray diffraction and energy dispersive spectroscopy. The characterizations demonstrate that the increase of in the liquidus temperature and the extension of the primary phase region facilitate the formation of primary phase-embedded composite structures. This work suggests that the computational thermodynamics approach can be serve as a potential tool to construct bulk metallic glass composites, especially to fabricate the primary phases-embedded bulk metallic glass composites. The findings of this work can be utilized to understand the formation of composite structures of bulk metallic glass composites.
10.1039-c5ra17786c	17	wear; composites; coating; friction; composite; coatings; surface; tribological; properties; wear resistance; resistance; powder; sliding; matrix; wear rate	The Cu-based electrical contact composites containing reinforcement (Cr2Nb particles) and solid lubricants (NbSe2 particles) were fabricated by a powder metallurgy method, and their mechanical and electrical properties were investigated. The wear tests of Cu-based composites were performed on a ball on disc under dry sliding conditions in a laboratory atmosphere and the worn surface of the Cu-based composites was observed by using scanning electron microscopy. Experimental results indicated that Cu-based composite materials containing Cr2Nb and NbSe2 nanofibers possessed lower electrical resistivity and better prominent tribological properties than Cu/NbSe2 and Cu/Cr2Nb composites, and that the friction coefficient and wear rate of the composites gradually decreased with the increase of NbSe2 nanofiber content. The lubricating effect of the Cu-based composites containing 25 wt% NbSe2 nanofibers and 10 wt% Cr2Nb particles was outstanding with a friction coefficient close to 0.15. The tribological properties of Cu-based composites were affected by the size and morphology of NbSe2 particles, and Cu-based composites with NbSe2 nanofibers have been proven to be more effective to reduce friction and wear compared to Cu-based composites containing commercially available NbSe2 micro-particles under dry sliding conditions. Furthermore, the addition of Cr2Nb could improve the hardness and oxidation resistance of composites, and consequently enhance wear resistance and conductivity of Cu-based composites.
10.1039-c5ra19719h	-1		A high strength and wear-resistance nickel-aluminum bronze alloy was successfully prepared by hot-pressing sintering. The tribological performances of it sliding against AISI 52100 steel were studied in distilled water, seawater, divalent salt solutions and monovalent salt solutions. The effects of the main components of seawater on the tribological properties were first investigated. The results show that Cu-9Al-5Ni-4Fe-Mn alloy has a lower friction coefficient and wear rate in seawater and divalent salt solutions. The Cl- and SO42- adsorbed by the surface can accelerate corrosion and promote the formation of Cu2O, Al2O3, FeOOH and Fe2O3, which has an influence on the tribological performances. The distribution of CaCO3 and Mg(OH)(2) on the surface also plays an important role in the reduction of the friction coefficient and wear rate. In addition, many substances transfer from the alloy to the steel surface and forma transfer layer during the friction process.
10.1039-c5ra22978b	-1		In the present work, an effective and facile one-pot dealloying strategy has been developed to synthesize monolithic asymmetry-patterned nanoporous copper ribbons (AP-NPCRs) from melt-spun bi-phase Al 32 at% Cu alloy with trace alpha-Al. The microstructure and nanoporosity of these AP-NPCRs were characterized using X-ray diffraction, scanning electron microscopy, energy dispersive X-ray analysis, transmission electron microscopy, high-resolution transmission electron microscopy, and Brunauer-Emmett-Teller measurements. The results show that the cooling rate and dealloying solution have a significant influence on formation, microstructure and nanoporosity of AP-NPCRs. The quenching surface of porous products has regular bimodal channel size distributions regardless of corrosive solution species, while the free surface shows a homogeneous porous network nanostructure in acidic solution and anomalous bimodal nanoporous architecture in alkaline medium. Additionally, the microstructure (surface morphology, ligament/channel sizes and distribution) and nanoporosity of AP-NPCRs can be modulated effectively by simply changing the dealloying solution.
10.1039-c6ra13057g	-1		In this work, we have investigated the heating and cooling processes for ternary (Au-x-Cu-y-Ni-y)(N=32,108,256) nanoclusters with different Au mole fractions (x = 0, 0.1, 0.3, 0.5, 0.7, and 0.9) using molecular dynamics simulation. We have examined the effect of addition of Au atoms to Cu-Ni nanoclusters on the different thermodynamic, structural, and dynamical properties. Our thermodynamic results showed that the most stable structures (which correspond to the maximum melting points) for the sizes of N = 32, 108, and 256 are at x(Au) = 0.7, 0.5, and 0.33, respectively. Our structural results showed that the ternary nanoclusters have almost homogeneous structures and core-shell regimes cannot be seen for them. The Au atoms tend to lie at outermost layers and so, Cu and Ni atoms lie at innermost layers. Also, our dynamical results indicated that as the Au mole fraction increases, the self-diffusion decreases.
10.1039-c6ta10607b	-1		Cu-S based compounds are eco-friendly minerals, and some of them are potential thermoelectric materials for mid temperature range usage. These minerals belong to a large family, in which many compounds have never been investigated as thermoelectric materials. In this work, by using high-throughput screening based on several crystal structure features, we identified thirteen compounds as potential thermoelectric materials from the Inorganic Crystal Structure Database (ICSD), out of which nine of the compounds' thermoelectric properties have not been reported. Using ball milling mechanical alloying and spark plasmas sintering, Cu6Fe2S8Sn1 (mawsonite) and Cu16Fe4.3S24Sn4Zn1.7 (stannoidite) were successfully fabricated as single phase dense ceramics, and the zT values of these non-doped compounds are 0.43 and 0.24 @ 623 K, respectively. The screening criteria were also rationalized by establishing structure-property relationships and the topological similarity of the thirteen identified compounds was investigated.
10.1039-c7ce00818j	-1		Herein, we report the successful synthesis of single crystalline boron nanotubes in a Cu alloy via a novel and simple direct melt reaction process. The boron nanotubes are perfect single crystals with a beta-rhombohedral structure, whose size can be controlled and changed. The combined experimental and dynamic simulation results lead to the conclusion that the boron nanotubes in the Cu alloy can be considered as a crystal skeleton, closely related to the liquid structure and solidification characteristics of the Cu-B alloy, which is significantly affected by the cooling rate and boron concentration. In addition, the stable morphology of the boron nanotubes, which minimizes the energy content, is not a round tube but a parallelogram. Thus, boron tubes with large size range scale can be prepared in Cu alloys.
10.1039-c7ra08390d	-1		Nanoporous copper (NPC) with tunable ligaments was prepared by dealloying Cu-Y binary amorphous ribbons in sulfuric acid (H2SO4) solution. The ligament size of the NPC sample synthesized by dealloying Cu58Y42 metallic glasses (237 nm) is much smaller than the one by dealloying Cu72Y28 (406 nm). This result reveals that the microstructure of NPC can be strongly influenced by the alloy composition of precursor alloys. Then, NPC with different microstructures were applied in the sono-catalytic degradation of methyl orange (MO) dye. NPC produced by dealloying Cu58Y42 metallic glasses displayed superior sonocatalytic activity compared to commercial copper foil and the sample by dealloying Cu72Y28. The mechanism of the sono-Fenton-like process of NPC can be explained by being due to a combination of Cu ligament, H2O2 and ultrasound. In addition, the influence of the dealloying conditions (acid concentration, temperature and leaching time) on the ligament size of NPC was evaluated comprehensively, which could provide meaningful insight for further fabricating NPC with more desirable morphology and higher catalytic activity.
10.1039-c8cp06271d	-1		We present a new scheme for modeling of the ion self-diffusion coefficient. Our scheme broadens the applicable scope of the ab initio + modeling' approach, which combines modeling of the self-diffusion coefficient with ab initio predictions. Essential concepts in our scheme are domain division' and coarse-graining' of the diffusion network, according to calculated barrier energies. With the former concept, the diffusion network is divided into a few types of simple disjunct domains. Their networks are further simplified with the latter idea that groups some ion sites and regards them as just a single site. We applied this scheme to Cu diffusion in the epsilon-Cu3Sn phase of the Cu-Sn alloy and succeeded in reproducing experimental diffusion coefficients in a wide range of temperature.
10.1039-c9ja00268e	-1		In this paper, we present, for the first time, a quantitative analysis carried out using time-resolved prompt gamma activation analysis (T-PGAA), a recent technique currently under development at the ISIS Neutron and Muon Source in Oxfordshire. T-PGAA is a neutron technique based on the radiative capture reaction that allows simultaneous acquisition of the photon energy emitted by the object during irradiation and the time of flight of the neutron that starts the capture reaction. We discuss results from two Cu-based certified standards from MBH Analytical Ltd: a leaded bronze and a brass, in preparation for future applications such as archaeological copper alloys. Results show the validity of the quantitative analysis calculated through a new piece of data analysis software developed in-house for this technique through comparison with the certified values and XRF results.
10.1039-c9qi01521c	-1		Nanoporous binary alloys with customizable microstructures and unique properties are desirable for engineering applications in nanotechnology. In this work, a three-dimensional immiscible nanoporous Cu-Ag (NPCA) alloy with tunable porosity has been fabricated by dealloying Cu-Zr-Al-Ag metallic glasses. The relationship between the composition, dealloying time and temperature, and nanoporosity was systematically investigated. It has been found that addition of Ag substantially slows down the dealloying process, and a composition threshold (similar to 10 at% Ag) exists to form a uniform nanoporous structure for the Cu-Zr-Al-Ag glassy precursor. The evolution of the NPCA ligament size with dealloying time and temperature can be well described by a diffusion-based growth kinetic model. Moreover, the addition of Ag effectively enhances the surface enhanced Raman scattering (SERS) performance of the resultant nanoporous materials. The highest SERS enhancement factor (EF) of NPCA resulting from the precursor with 10 at% Ag content is 6 x 10(6), which is about 60 times greater than that of the nanoporous copper (NPC) without Ag, and the limit of detection (LOD) is 10(-11) mol L-1 to R6G. Our findings not only provide new insight into the formation mechanism of immiscible nanoporous alloys, but also are helpful for developing inexpensive SERS substrates with multiple metallic elements.
10.1039-d0ra10678j	2	corrosion; surface; film; electrochemical; films; spectroscopy; layer; current; solution; potential; resistance; composition; x-ray; ions; showed	Cupronickel alloys have been broadly utilized in various fields due to their excellent properties. In this paper, electrochemical impedance spectroscopy (EIS) and potentiodynamic polarization (PDP) curves were used to study the impact of different Mn contents on the corrosion resistance of 90/10 cupronickel alloy. Surface morphology, electronic structure, and phase composition of the film formed on different Mn content 90/10 cupronickel alloy immersed in 3.5% NaCl solution for 30 days were investigated using SEM, EDS, Mott-Schottky, XRD, XPS, etc., revealing that adding an appropriate amount of Mn to the 90/10 cupronickel alloy can change the corrosion resistance of the alloy. The corrosion resistance first increases and then decreases with the addition of Mn content. Among them, the sample with 0.87% Mn addition has the best corrosion resistance, the corrosion product film is more complete, no cracks appear, and the corrosion product binding force is stronger. The addition of Mn promotes the filling of cation vacancies by Ni and generates more NiO, which enhances the stability of the corrosion product film.
10.1039-d1ra06473h	2	corrosion; surface; film; electrochemical; films; spectroscopy; layer; current; solution; potential; resistance; composition; x-ray; ions; showed	Super-hydrophobic surfaces (SHS) usually are formed from a combination of low surface energy materials and micro/nanostructures via two-step approaches, and they have promising applications in material corrosion protection. In this paper, the authors obtained a super-hydrophobic surface onto the copper plates through a rapid one-step electrodeposition process from the electrolytic solution containing cobalt nitrate (Co(NO3)(2)center dot 6H(2)O), myristic acid, and ethanol. The electrochemical impedance spectroscopy and polarization curve are adopted to evaluate a super-hydrophobic surface's durability and corrosion resistance. The results demonstrate that the super-hydrophobic cobalt myristate coating showed excellent corrosion inhibition in simulated seawater solution with a corrosion inhibition efficiency as high as 98.82%. Furthermore, the super-hydrophobic layer could be considered a barrier and thus require an ideal air-liquid interface that inhibits the diffusion of the corrosive species. The construction of super-hydrophobic characters with a self-cleaning property is significant and used widely, attracting numerous studies for obtaining surfaces with low surface energy and micro/nanostructures. The as-fabricated super-hydrophobic surfaces possess the external surface adhesive force to the water phase and excellent self-cleaning and antifouling ability. By adjusting processing time, the water contact angle of the coated copper surface reaches 152.9 degrees, showing a superb superhydrophobicity. The morphology, chemical composition, and wettability characterization were analyzed using scanning electron microscopy (SEM), X-ray photoelectron spectroscopy (XPS), and contact angle measurements. In addition, a scanning Kelvin probe (SKP) usage in this work is to measure the atmospheric corrosion behavior of copper with the super-hydrophobic coating. Thus, this proposed method provides a simple way to rapidly equip super-hydrophobic coating onto the metal surface to realize corrosion inhibition.
10.1039-d1ra07219f	2	corrosion; surface; film; electrochemical; films; spectroscopy; layer; current; solution; potential; resistance; composition; x-ray; ions; showed	Metal surfaces can be polished effectively and in an environmentally friendly way by virtue of the mechanical and electrochemical interaction between ion-exchange resin particles and the metal substrate. This paper studied this 'dry' polishing process and its property effects on 65 brass alloys. Surface morphology analysis revealed that the surface roughness can be reduced by over 71.5% from 0.764 +/- 0.031 mu m to 0.218 +/- 0.080 mu m with longer polishing time, and by over 67.1% from 0.764 +/- 0.031 mu m to 0.252 +/- 0.02 mu m with higher voltage. XPS and EDS results showed that only a small amount of oxygen species remained on the polished metal surface, while Cu and Zn were apparently present in the metallic state. The decrease in self-corrosion current indicated by the Tafel curves and the increase in the radius of the capacitive reactance circle contained in the Nyquist plots indicate that the surface corrosion resistance of the polished materials has been improved.
10.1039-d4ra04758c	2	corrosion; surface; film; electrochemical; films; spectroscopy; layer; current; solution; potential; resistance; composition; x-ray; ions; showed	Weight loss (WL), electrochemical, and surface analysis were used to explore the efficiency of lentil seed extract (LSE) in mitigating the electrochemical corrosion of Cu-10Ni and Cu-30Ni alloys in obviously aerated water. The adsorption of lentil seed extract (LSE) species to create a barrier layer improved the corrosion resistance of Cu-Ni alloys in a NaCl medium. It was shown that the temperature of the medium and the amount of extract used affected the enhanced inhibitory efficacy. Using the PDP approach, the Cu-10Ni alloy showed the maximum inhibition performance (IE) of about 98.58% and 8.53% with 300 ppm LSE, respectively. According to the findings, the studied extract had a good ability to slow down the step at which alloys corroded in a 3.5% NaCl solution. It was discovered that as the temperature rose, the rate of corrosion increased. The thermodynamic activation functions of the dissolution process were also calculated as a function of extract dose. PDP curve analysis reveals that LSE is a mixed-type inhibitor, and EIS findings demonstrates that increasing dose not only alters the charge transfer (Rct) of Cu-10Ni alloy from 1031 to 2984 Omega cm2 and for Cu-N30Ni alloy from 3093-6208 Omega cm2 but also changes the capacitance of the adsorbed double layer (Cdl) for Cu-10Ni alloy from 728-678 mu F cm2 and for Cu-30 Ni alloy from 726 to 701 mu F cm2. The inhibitor's adsorption provides a good fit for the Freundlich, Temkin, and Langmuir isotherm models. Several methods are used to confirm that the alloy surface has a protective coating. Weight loss (WL), was used to explore the efficiency of lentil seed extract (LSE) in mitigating the corrosion of Cu-10Ni and Cu-30Ni alloys in obviously aerated water.
10.1039-d5ra00613a	-1		Porous metals (PMs) have attracted significant attention in recent years due to their unique structural and functional properties, holding potential for a wide range of applications in catalysis, sensing, energy storage, and filtration. Among these, porous copper (PC), which is produced by dealloying copper-zinc (Cu-Zn) alloys has evolved as a particularly valuable material. In this study, a Cu-Zn alloy is electrochemically deposited onto a Cu wire in a sulphate-based electrolyte containing tri-sodium citrate as a complexing agent. To produce PC, the alloy has been subjected to chemical dealloying to dissolve the less noble element. We have implemented machine learning algorithms such as adaptive neuro-fuzzy inference systems (ANFIS), artificial neural networks (ANN), and response surface methodology (RSM) to model the interaction of process parameters and responses. Statistical modeling has been carried out to investigate the influence of operating parameters, including precursor reagent quantities (0.002-0.2 M), electrodeposition time (15-45 min), and dealloying time (16-24 h), on Zn content, dealloyed weight, and change in grain size. The test results confirm that both models fit the experimental data well, with the ANN model achieving high accuracy (R2 = 0.98, 0.96, and 0.96 for Zn content, dealloyed weight, and grain size change, respectively); however, the ANFIS model demonstrates superior performance with the highest R2 value (0.99) and the lowest MAPE (0.003, 0.002, and 0.001 for the respective responses). The RSM-BBD model is best suited for analyzing parameter interactions on responses, as it systematically evaluates the combined effects of multiple variables. By using potentiodynamic polarization curves to compare the corrosion resistance of Cu-Zn electrodes to bare Cu and PC electrodes, it was found that Cu-Zn electrodes have better corrosion resistance. Additionally, dealloying has resulted in a transition from a hydrophobic (110 +/- 1 degrees) to a hydrophilic (59 +/- 0.5 degrees) surface.
10.1049-mna2.12128	6	grain; deformation; strain; strength; dislocation; cu-; tensile; size; ecap; grain size; sfe; ductility; hardening; high; stress	For the sake of comprehending the mechanical mechanisms of nano-twinned (NT) Cu-Ag alloys with grain boundary affect zone (GBAZ) segregation, molecular dynamics (MD) simulations were used to observe its behaviours during the nano-indentation progress. The effect of grain size, alloying atoms (Ag) content as well as twin boundary spacing (TBS) on the deformation behaviours are considered in this investigation. The open visualization tool OVITO is used to directly observe the deformation progress of nanocrystals during nano-indentation. The reaction between lattice dislocations and twin boundaries is recorded and analyzed in detail as the indentation deepens. The simulation results demonstrate a positive correlation between the twin boundary spacing and the occurrence of dislocations. The dislocation rings will appear more effortlessly as the TBSs increase. Meanwhile, it is frequently observed that the face centre cubic (FCC) atoms are transformed into body centre cubic (BCC) atoms. This work will help to seek for novel metal materials with high strength, high ductility and great electrical conductivity.
10.1049-mnl.2013.0113	-1		Hierarchical porous copper bulk can be fabricated through chemical dealloying of porous CuAl intermetallics under free corrosion conditions. The obtained precursor porous CuAl intermetallics and as-dealloyed hierarchical porous copper were characterised using X-ray diffraction, a field-emission scanning electron microscope and energy dispersive X-ray spectroscopy. It was found that the hierarchical porous copper can be easily prepared by this method. The dealloying solution will dramatically influence the morphology of the resultant hierarchical porous materials. As a result, trimodal porous copper composite material and bimodal porous copper can be achieved after being dealloyed in NaOH and HCl solutions, respectively. Therefore, the mechanisms of the evolution of hierarchical pores structure are also discussed.
10.1051-jp4-1996870	4	transformation; martensite; martensitic; phase; shape; beta; memory; shape memory; temperature; temperatures; martensitic transformation; gamma; transformation temperatures; effect; thermal	Pronounced peculiarities of the frequency and amplitude dependences of the amplitude-dependent internal friction have been revealed in martensitic beta(1)' phase of quenched Cu-Al-Ni single crystals at temperatures 200-340 K. These peculiarities were not observed in beta(1)' phase for crystals, subjected to ageing in austenite. Application of several experimental techniques, one of which enabled to observe directly a reversible anelastic strain during amplitude-dependent internal friction measurements, allowed to attribute the observed peculiarities of the frequency dependence in quenched samples to relaxation phenomena due to an interaction of mobile partial dislocations with mobile pinning obstacles.
10.1051-jp4-1996894	4	transformation; martensite; martensitic; phase; shape; beta; memory; shape memory; temperature; temperatures; martensitic transformation; gamma; transformation temperatures; effect; thermal	The shape memory alloys present, in the high temperature phase, a super-elastic behaviour : during a super-elastic test, the martensitic transformation is induced by the stress, and a large reversible deformation is observed. With a single crystal, the maximum superelastic deformation reaches 8 to 10%. During the tensile test on a single crystal, only one variant of martensite is induced in the shape of many parallel needles. Using a specific tensile machine, we have measured the friction due to the movement of the interfaces between the austenite and the martensitic phases. These measurements have been realised during a tensile test on single crystals of CuZnAl. The movement of the interfaces is obtained by a low sinusoidal stress that is superimposed to the tensile stress. Results show that the interfaces are progressively pinned when the super-elastic strain is maintained constant. This pinning disappears when the strain is slightly increased.
10.1051-jp4-1997536	4	transformation; martensite; martensitic; phase; shape; beta; memory; shape memory; temperature; temperatures; martensitic transformation; gamma; transformation temperatures; effect; thermal	We have studied the martensitic transformation and the order-disorder transitions in two families of composition related Cu-Al-Mn crystals. X-ray diffraction and calorimetric measurements have been performed to characterize order-disorder transitions. The entropy change at the martensitic transition has been computed from calorimetric measurements. Results show that its magnitude depends only on the martensite structure which, in turn, depends on the electronic concentration e/a. We have obtained Delta S = 1.51 +/- 0.05 J mol(-1) K-1 for a transition to a 2H phase and Delta S = 1.26 +/- 0.06 J mol(-1) K-1 for a transition to a 18R structure. We discuss the possibility of a magnetic contribution to Delta S. Finally it is found that quenching has a marked influence on the martensitic transition temperature, but it does not affect the entropy change.
10.1051-jp4-1997551	4	transformation; martensite; martensitic; phase; shape; beta; memory; shape memory; temperature; temperatures; martensitic transformation; gamma; transformation temperatures; effect; thermal	The effect of isothermal ageing of beta-Cu-Al-Ni alloys at low temperatures (473K and 573K) on the martensitic transformation has been studied using differential scanning calorimetry and transmission electron microscopy. Three single crystals with different Al content (13.5, 13.6 and 13.8 wt%) and the same Ni concentration (4%) were used. Before ageing, the samples were annealed at 1070K and quenched to room temperature. The transformation temperatures remained nearly constant during the initial stages of ageing and started to increase noticeably after a given ageing time, which is shorter in the samples with higher Al content. For the alloy with highest Al content, the Ms decreased slightly at the beginning of ageing at 473K. The transformation to two coexisting martensitic structures, beta' (18R) and gamma' (2H) has been observed. The proportion of each one changes with the composition and ageing, the gamma' phase being promoted for increasing ageing times and temperatures. A good correlation exists between the initial ageing stage, in which there is no evolution of transformation temperatures, with the coexistence of the two martensites. The formation of the two kinds of martensites is related to the short range reordering processes taking place during ageing, specially of as quenched next nearest neighbours disordered Cu-Al pairs. The results would indicate that the disordered Cu-Al pairs stabilize the beta' martensite and when these pairs recover the correct positions, the gamma' becomes the stable martensite. The high increase of transformation temperatures with ageing at 573K is related to two different precipitation processes observed.
10.1051-jp4-1997584	4	transformation; martensite; martensitic; phase; shape; beta; memory; shape memory; temperature; temperatures; martensitic transformation; gamma; transformation temperatures; effect; thermal	Pseudoelastic cycling of Cu-Zn-Al single crystals has been shown to induce microstructural changes in the material. The mechanical response is also altered. However, some of the observed changes in the mechanical behavior are at least partially recovered at temperatures at which point defects are mobile. In this work results are presented in order to analyze the different contributions associated to the changes of the mechanical behavior during pseudoelastic cycling and in a subsequent ageing stage in the P-phase condition for Cu-Zn-Al single crystals. The magnitudes and kinetics of the recoverable changes are analyzed and compared with the other known phenomena that take place at these temperatures, i.e. the martensite stabilization and the beta phase recovery. Results show that the evolution is not simply related to these phenomena. Additional contributions, like point defects generation during cycling and the effect of dislocation array on the beta phase recovery, need to be considered.
10.1051-jp4-2001826	4	transformation; martensite; martensitic; phase; shape; beta; memory; shape memory; temperature; temperatures; martensitic transformation; gamma; transformation temperatures; effect; thermal	The ageing behaviour of the martensite in single crystals made from the quaternary alloy (Cu-9.04 at%Zn-20.97 at%Al-3.07 at%Ni) was investigated, together with a characterization of the structure and the microstructure in the initial condition. The long range ordering temperatures were determined by electrical resistivity measurements. The stabilization of stress induced martensite was quantitatively studied as a function of time and temperature. After performing the same thermal treatment as for the ageing experiments, slices for transmission electron microscopy were cut and the resulting structure and microstructure were analyzed, The high temperature beta phase is long range ordered and the martensite has the 18R structure, No evidence for the appearance of gamma precipitates was found after a quench from 770 K. However, a large number of vacancy loops with straight borders lying in {110} planes were present, with the corresponding dislocations dissociated in partials. It was also found that the stabilization process takes place in the martensite, but with a slower kinetics than in Cu-Zn-Al.
10.1051-jp4-20031024	4	transformation; martensite; martensitic; phase; shape; beta; memory; shape memory; temperature; temperatures; martensitic transformation; gamma; transformation temperatures; effect; thermal	Development of multicomponent TiNi-based shape memory alloys from initial amorphous state continue attracts attention due to unique mechanical properties in the supercooled liquid region and specific microstructure formed after crystallisation. Amorphous ribbons were produced by single-roll casting technique. Those ribbons demonstrate high shaping ability near glass transition temperature T-G. The material structure was examined by the XRD, TEM/SAD techniques; the thermodynamic properties were studied by DSC; the mechanical and functional (shape memory, superelasticity) properties were studied in tension. The effect of crystallisation conditions and the resulting microstructural state (partly or fully crystallised, precipitates accompanying crystallisation) on the martensite transformation and associated functional properties is discussed.
10.1051-meca-2024039	3	sma; shape; shape memory; memory; smas; superelastic; bars; damping; cu-al-mn; mechanical; bending; applications; numerical; sma bars; material	In the electronics industry sector, different types of parts made out of copper alloys are used, such as metal supports (lead frames), on which the chips are assembled. These parts are produced using progressive dies, with several blanking and bending stages. There is a huge interest to numerically predict these multistage forming processes, to decrease design time and to anticipate production problems such as non-compliance with dimensional tolerances depending on the material used. This paper deals with the progressive forming of copper parts with single and multi-stage process coupled with experimental and numerical approaches for bending operations. The main contribution of this study is the design of a single stage bending tool for rectangular samples representative of multi-stage industrial processes, providing a relevant experimental database for numerical model validation. This device is based on the technology of progressive dies, though it allows the production of one part at a time. Instrumentation provides local load and displacement and an experimental database is built for Cu-ETP R290 copper strip. A multi-stage bending industrial process dedicated to the manufacturing of electrical contacts is also considered in this study. Numerical models of both single and multi-stage processes are developed, with a focus on the technological importance of a cam slider for the industrial process. The results show that the bending force is mainly influenced by the sample width . In addition, numerical models for the rectangular geometries capture some of the trends from the experiment such as the proportionality of the maximum force with the bent width . Overall, the models are able to predict springback within the process tolerance. Finally, comparison of one stage of the bending sequence with the single stage bending model showed that the single model approach gives similar results in terms of load and plastic deformation.
10.1061-(ASCE)MT.1943-5533.0003478	-1		Recently, single-crystal Cu-Al-Mn (CAM) superelastic alloy (SEA) bars have been developed to address the shortcomings of traditional Ni-Ti SEA bars, i.e., high cost, low workability, and lack of superelasticity at low temperatures. The CAM SEAs have a wide range of potential applications in biomedical, aerospace, mechanical, and civil industries. However, no quantitative information is available on the chemical stability of this relatively new metal alloy. This study quantified the chemical resistance of CAM SEA bars compared with that of mild steel bars in terms of mass loss and changes in mechanical and physical properties. Tensile testing was performed to estimate the reduction in the yield load of the samples after chemical aging. Scanning electron microscopy (SEM) and energy dispersive X-ray spectroscopy (EDS) were carried out to determine the oxidation potential of the material. Corrosion parameters of CAM SEAs were quantified through potentiodynamic polarization tests. The erosion rate of CAM SEAs was also estimated using these corrosion parameters to compare against the typical values reported for mild steel. The CAM SEAs had a chemical resistivity significantly superior to that of mild steel regardless of the environmental exposure conditions tested in this paper. It was also found that CAM SEAs have comparable corrosion resistance to another Cu-based shape memory alloy composition: Cu-Al-Ni.
10.1061-(ASCE)MT.1943-5533.0003874	3	sma; shape; shape memory; memory; smas; superelastic; bars; damping; cu-al-mn; mechanical; bending; applications; numerical; sma bars; material	This paper examines the feasibility of roll-threading superelastic Cu-Al-Mn shape memory allow (SMA) rods. The key idea behind this study was to perform roll-threading between quenching and aging, where cold workability of the material is relatively high . To obtain excellent superelasticity, single-crystal superelastic Cu-Al-Mn SMA rods were prepared with 16-mm diameter and 300-mm length . Threadability was studied by dimensional inspection and surface observations. Mechanical properties of the threaded rods were examined by cyclic tension tests. Comparisons between rolled and cut threads were made by cutting each single-crystal rod into halves to obtain two rod specimens having the same crystal orientation, thus ensuring fair comparison by excluding the influence of variations in orientations of the single-crystal rod. From the study, it was demonstrated that roll-threading of Cu-Al-Mn SMA rods was possible if roll-threading is performed between quenching and aging. Since additional heat treatment from the ordinary manufacturing process is unnecessary, roll-threading of Cu-Al-Mn SMA rods is as easy as that of steel rods. It was also demonstrated that the roll threads had significantly superior fatigue resistance compared with the cut threads of the same size. These results suggest that superelastic Cu-Al-Mn SMA rods with rolled threads are suitable for mass production to be used in structural and earthquake engineering applications.
10.1061-JMCEE7.MTENG-17497	-1		Cu-Al-Mn (CAM) shape memory alloys (SMAs) are cost effective, have a high low-cycle fatigue life and superelastic limit, and a wide temperature application range compared with other types of SMAs. These characteristics of CAM SMAs have resulted in increased interest in their use in civil engineering applications, particularly as reinforcement in concrete structures and as dampers in steel structures. However, these applications require machining of the CAM SMA bars for connection with other structural elements. This study presents the methods and results of the first systematic research on the machinability of CAM SMAs. The key machinability characteristics of CAM SMAs: chip formation, cutting temperature, tool wear, workpiece surface roughness, and diameter deviation, were studied and compared with those of conventional NiTi SMAs and commonly used steels: mild steel (MS) and 304 stainless steel (SS). The effects of a wide range of cutting parameters: cutting speed ranging from 15 to 120 m/min, feed rate ranging from 0.1 to 0.2 mm/revolution, and depth of cut ranging from 0.5 to 1.5 mm, were investigated. The results from this study showed that the tool wear from machining CAM SMAs was close to that from machining SS and slightly higher than that from machining MS, but much lower than that from machining NiTi SMAs. In all the cases considered here, the tool wear from machining CAM SMAs was found to be 0.6-1.8 times that from machining SS, 0.8-2.4 times that from machining MS, and 1/7-1/21 that from machining NiTi SMAs. After a continuous machining test with a total cutting length of 4.5 m, the nose wear from machining CAM SMAs was found to be 1.6 times that from machining MS, the average flank wear from machining CAM SMAs was found to be three times that from machining MS, and the diameter deviation (relative diameter difference from that of the first sample) of CAM SMAs was only 10 mu m larger than that of MS.
10.1063-1.1367401	-1		Grain growth and strain release processes in the electrodeposited nanocrystalline (nc) Cu specimen with a high purity were investigated by means of differential scanning calorimetry, x-ray diffraction, electrical resistance measurement, and high-resolution transmission electron microscopy. It was found that for the as-deposited nc Cu, the grain growth started at about 75 degreesC, at which the microstrain in (111) plane (e(111)) began to release, while the mean microstrain and that in (100) plane (e(100)) began to release at a higher temperature (150 degreesC). With an increment in microstrain in the nc Cu introduced by cold rolling, the grain growth onset temperature increased while the strain release onset temperature dropped obviously. These results showed an evident correlation between the grain size stability and the microstrain in the nc materials. The activation energy for the grain growth was determined by using Kissinger analysis and isothermal kinetics analysis, being about 86 kJ/mol, implying that the grain growth process is dominated by grain boundary diffusion. (C) 2001 American Institute of Physics.
10.1063-1.1459597	-1		We investigate persistent photoconductivity in polycrystalline Cu(In,Ga)Se-2 thin films by measuring the transient behavior of their electrical conductivity under and after illumination. Characteristic nonexponential transients of the conductivity under and after illumination extend over more than four orders of magnitude in time. From this result, we conclude that the persistent photoconductivity in Cu(In,Ga)Se-2 cannot be explained by the mesoscopic barrier model. Rather, it is a microscopic effect which can be understood in the frame of a large lattice relaxation model. Investigation of the conductivity under monochromatic subband gap illumination determines the minimum photon energy for the direct excitation of the persistent photoconductivity to be approximately 0.6 eV. Hall effect measurements identify the persistent photoconductivity as a hole density effect in the bulk of the Cu(In,Ga)Se-2 grains, consistent with the lattice relaxation model. (C) 2002 American Institute of Physics.
10.1063-1.1850589	-1		The present work is devoted to an investigation of the formation of the nanoscale icosahedral phase in Cu55Zr30Ti10Pd5 and Cu50Zr30Ti10Pd10 bulk glassy alloys by synchrotron x-ray radiation. Calculations based on the x-ray and selected-area electron diffraction patterns indicate that this phase has a high degree of icosahedral order. Kinetics of the devitrification of Cu55Zr30Ti10Pd5 is also studied in detail. (C) 2005 American Institute of Physics.
10.1063-1.1925784	-1		Excimer laser melting and lateral resolidification is demonstrated in 200 nm thick Cu and Au elemental metal thin films encapsulated between SiO2 layers. Projection irradiation is used to selectively and completely melt lines 3 to 30 mu m wide in the metal film-with rapid lateral solidification originating from the unmelted sidewalls of the molten region-resulting in large columnar grains, extending transversely to the middle of the line. Transmission electron microscopy reveals twinning structures and other defects typical of rapid solidification. Encapsulation and control of the fluence are found to be crucial parameters necessary to prevent film dewetting while molten. (c) 2005 American Institute of Physics.
10.1063-1.2006218	11	glass; bulk; metallic; bulk metallic; gfa; bmg; glassy; metallic glass; ability; bulk metallic glass; amorphous; addition; crystallization; mm; glass-forming	Zr48.5Cu46.5Al5 bulk metallic glass matrix composites with diameters of 3 and 4 mm were produced through water-cooled copper mold casting. Micrometer-sized bcc based B2 structured CuZr phase containing martensite plate, together with some densely distributed nanocrystalline Zr2Cu and plate-like Cu10Zr7 compound, was found embedded in a glassy matrix. The microstructure formation strongly depends on the composition and cooling rate. Room temperature compression tests reveal significant strain hardening and plastic strains of 7.7% and 6.4% before failure are obtained for the 3-mm- and 4-mm-diam samples, respectively. The formation of the martensite phase is proposed to contribute to the strain hardening and plastic deformation of the materials. (c) 2005 American Institute of Physics.
10.1063-1.2388868	-1		High pressure torsion was applied to produce disk-shape specimen of Cu60Zr20Ti20 composition. Radial dependence of the microstructure was monitored by x-ray diffraction, scanning, and transmission electron microscopies. The disk consists of a top surface layer, homogeneous on a micrometer scale with an average thickness of 10-20 mu m, and an inhomogeneous bulk region of 200 mu m thickness. Calorimetric studies revealed that the disk contains detectable amount of amorphous phase. Characteristics of this amorphous content were compared to a fully amorphous melt-quenched Cu60Zr20Ti20 ribbon. (c) 2006 American Institute of Physics.
10.1063-1.2429017	7	irradiation; shear; grain; ta; deformation; size; radiation; voids; nanocrystalline; simulations; similar; void; temperature; irradiated; boundaries	While amorphous phases have been reported in immiscible alloy systems, there is still some controversy regarding the reason for the stabilization of these unusual amorphous phases. In this letter, using three-dimensional atom probe tomography, direct evidence of nanoscale phase separation within the amorphous phase forming in immiscible Cu-Nb alloy thin films has been presented. This evidence clearly indicates that the nanoscale phase separation is responsible for the stabilization of the amorphous phase in such immiscible systems since it substantially reduces the free energy of the undercooled liquid (or amorphous) phase, below that of the competing supersaturated crystalline phases. (c) 2007 American Institute of Physics.
10.1063-1.2799087	6	grain; deformation; strain; strength; dislocation; cu-; tensile; size; ecap; grain size; sfe; ductility; hardening; high; stress	We have investigated electrical resistivities of high-purity ultrafine-grained Cu containing different concentrations of nanoscale growth twins, but having identical grain size. The samples were synthesized by pulsed electrodeposition, wherein the density of twins was varied systematically by adjusting the processing parameters. The electrical resistivity of the Cu specimen with a twin spacing of 15 nm at room temperature (RT) is 1.75 mu Omega cm (the conductivity is about 97% IACS), which is comparable to that of coarse-grained (CG) pure Cu specimen. A reduction in twin density for the same grain size (with twin lamellar spacings of 35 and 90 nm, respectively) results in an increment in electrical resistivity from 1.75 to 2.12 mu Omega cm. However, the temperature coefficient of resistivity at RT for these Cu specimens is insensitive to the twin spacing and shows a consistent value of similar to 3.78x10(-3)/K, which is slightly smaller than that of CG Cu (3.98x10(-3)/K). The increased electrical resistivities of the Cu samples were ascribed dominantly to the intrinsic grain boundary (GB) scattering, while the GB defects and GB energy would decrease with increasing twin density. Transmission electron microscope observations revealed the GB configuration difference from the Cu samples with various twin densities. Plastic deformation would induce an apparent increase in the resistivity. The higher of the twin density, the higher increment of RT resistivity was detected in the Cu specimens subjected to 40% rolling strain. Both the deviated twin boundaries and strained GBs may give rise to an increase in the resistivity. (C) 2007 American Institute of Physics.
10.1063-1.2968240	-1		Molecular dynamics simulations and selected experiments have been carried out to study the growth of Cu films on (010) bcc Ta and the deposition of CuxTa1-x alloy films on (111) fcc Cu. They indicate that fcc Cu films with a (111) texture are always formed when Cu is deposited on Ta surfaces. These films are polycrystalline even when the Ta substrate is single crystalline. The grains have one of two different orientations and are separated by either orientational or misfit dislocations. Periodic misfit dislocations and stacking faults develop within these grains to release structure difference induced misfit strain energy. The Cu film surface roughness was found to decrease with increase in the adatom energy for deposition. When CuxTa1-x is deposited on Ta, the films always have a higher Cu composition than that of the vapor mixture. This arises from a surface segregation phenomenon. When the Cu and Ta fractions in the films are comparable, amorphous structures form. The fundamental origins for the segregation and amorphization phenomena are discussed. (C) 2008 American Institute of Physics.
10.1063-1.2999592	-1		Ternary Zr-Cu-Ti system, especial with a high Ti content, is normally difficult to be fully vitrified. In this paper, we demonstrate that cosputtering can produce amorphous Zr-Cu-Ti thin films with an excessive Ti content even as high as 19%. Sub-T-g annealing of the film induces the formation of medium-range-ordered clusters and to raise the nanohardness by 35% to 6.6 GPa. The promising mechanical properties of the sub-T-g annealed Zr52Cu29Ti19 films offer great potential for microelectromechanical system applications.
10.1063-1.3073984	-1		We investigate the pseudoelastic behavior at room temperature of composite nanowires using molecular dynamics simulations. The nanowires are composed of a nickel core surrounded by a copper shell, leading to high coherency stresses. The coherency and surface stresses cause the nanowires to undergo a lattice reorientation, by twinning, from < 001 > to < 110 > during relaxation. Nanowires of different cross-sectional areas (varying from 2.17x2.17 up to 2.9x2.9 nm(2)) were studied. In all cases, under tensile loading, the nanowires reorient to < 001 > and then under unloading reorient back to < 110 >, thus exhibiting pseudoelastic behavior. This behavior is more pronounced in composite nanowires with a coherent interface than for single crystal nanowires.
10.1063-1.3132752	4	transformation; martensite; martensitic; phase; shape; beta; memory; shape memory; temperature; temperatures; martensitic transformation; gamma; transformation temperatures; effect; thermal	The elastic and dissipative properties of nanostructured superconducting fiber composites Cu-32 vol.% Nb at frequencies of the order of 70 kHz are investigated in the temperature range 2-320 K. The composites, prepared by the method of intensive plastic deformation, consist of a fragmented copper matrix uniformly filled with niobium fibers having diameters of 200-500 nm. It is found that the acoustic properties of the composite are mainly determined by the properties of the copper matrix. Near 90 K a relaxation peak of the internal friction is observed, with activational parameters close to those of the Bordoni peak in copper. Below 12 K the temperature dependence of the dynamic Young's modulus is described by the thermally activated relaxation of two-level systems in a highly disordered medium. The influence of high-temperature annealing on the observed effects is investigated.
10.1063-1.3357310	4	transformation; martensite; martensitic; phase; shape; beta; memory; shape memory; temperature; temperatures; martensitic transformation; gamma; transformation temperatures; effect; thermal	This work presents careful adiabatic calorimetry measurements of the temperature memory effects on a Cu-Al-Ni shape memory alloy single crystal. These effects, which appear after partial martensitic transformations, have been systematically studied. The subsequent delay of the transformation as a function of the thermal history is described by means of a straightforward model, which makes full use of the phase transformation thermodynamic functions, carefully determined from the specific heat results. This model predicts on quantitative grounds, the decrease in the transformed mass in the successive thermal cycles. It also provides information about the distribution of the elastic energy among the martensitic plates in the low temperature phase, which is a characteristic feature of these alloys. The knowledge of the elastic states is not only required to analyze the properties of the martensitic phase but also to describe the kinetics of any physical quantity in the reverse transformation. (C) 2010 American Institute of Physics. [doi: 10.1063/1.3357310]
10.1063-1.372296	-1		Fe precipitates in a Cu-fcc matrix, prepared using the Bridgeman method and with an average composition of Cu97Fe3, displayed the coexistence of ferromagnetism (FM), spin glass-like (SGL) behavior and antiferromagnetic (AFM) correlations. The two former contributions may be attributed, respectively, to the segregation of FM, alpha-Fe-bcc precipitates and to the few Fe spins distributed in the matrix. The annealing procedures increased the FM contribution and, as particle growth and phase segregation took place, the SGL behavior progressively disappeared. Results from high resolution transmission electron microscopy (HRTEM), x-ray photoelectron spectroscopy (XPS), and electron energy-loss spectroscopy (EELS) suggest that the AFM correlations are due to the alpha-Fe particles that show a surface layer of a few nanometers in thickness, of either FeO and/or gamma-Fe-fcc. XPS and EELS measurements confirm the presence of FeO; however, the latter is only tentatively suggested by the HRTEM analysis of the particle/matrix interfaces. (C) 2000 American Institute of Physics. [S0021-8979(00)08106-8].
10.1063-1.373669	9	magnetic; magnetization; magnetoresistance; temperature; superparamagnetic; annealing; gmr; field; magnetic properties; ferromagnetic; granular; samples; magnetic field; melt-spun; particles	Ferromagnetic resonance (FMR) spectra (derivatives of microwave power absorption) were measured in a granular, ribbon-shaped melt-spun Cu90Co10 alloy in a wide range of temperatures from 10 K up to room temperature. Prior to measurements the sample was annealed at 773 K for 1 h in order to create a well-developed granular structure. The results are interpreted using the Kittel FMR equations originally introduced for thin ferromagnetic films, as well as by using an Arrhenius-type exponential function for superparamagnetic relaxations. These results are also compared with the experimental data obtained from low-field susceptibility measurements in both, zero-field-cooling and field-cooling modes. It is shown that FMR spectroscopy is a useful tool for studying magnetic properties of granular magnets consisting of nanometer-scale single-domain particles, in particular, if the resonance spectra are measured in a wide range of temperatures, thus allowing for identification of the magnetic phases of the particles. The derived value of 10(-13) s for the characteristic time of superparamagnetic relaxations is four orders of magnitude smaller than that commonly used while analyzing data yielded by just one measuring technique. The obtained results allowed us to estimate the first order constant of the magnetocrystalline anisotropy for fcc Co particles in the copper matrix K-1=-4.2x10(6) erg/cm(3). (C) 2000 American Institute of Physics. [S0021-8979(00)07213-3].
10.1063-1.4711007	2	corrosion; surface; film; electrochemical; films; spectroscopy; layer; current; solution; potential; resistance; composition; x-ray; ions; showed	In this second part of our study on fractal co-electrochemical deposition, we investigate the Cu-Zn system. Macroscopic and microscopic inspection shows a sensitive dependence of the morphology of the final pattern on initial concentrations. The pattern is seen to undergo a transition from classical dendrites to randomly ramified deposits, with each slight increase in [Cu2+](0), while [Zn2+](0) is maintained constant. The variational trends in chemical composition, growth velocity, and fractal dimension with increasing [Cu2+](0) are analyzed. The latter is seen to generally increase with copper (II) ion concentration. In contrast, the growth rate of the deposits is seen to decrease with increasing concentration of Cu2+ ions. A new probe of dense ramified morphology, the pattern density, is introduced and seen to increase with [Cu2+](0). XRD measurements reveal that the observed properties correlate with the birth of copper-rich nuclei, which disrupt the crystalline anisotropy of the two-metal alloy. (C) 2012 American Institute of Physics. [http://dx.doi.org/10.1063/1.4711007]
10.1063-1.4766389	13	clusters; atomic; glass; atoms; composition; dynamics; metallic; icosahedral; glasses; simulations; molecular; cu-zr; molecular dynamics; metallic glasses; structural	Under the framework of smoothed and long range second-moment approximation of tight-binding, a realistic interatomic potential was first constructed for the Cu-Zr-Hf ternary metal system. Applying the constructed potential, Monte Carlo simulations were carried out to compare the relative stability of crystalline solid solution versus its disordered counterpart over the entire composition triangle of the system (as a function of alloy composition). Simulations not only reveal that the origin of metallic glass formation but also determine, in the composition triangle, a quadrilateral region, within which metallic glass formation is energetically favored. It is proposed to define the energy differences between the crystalline solid solutions and disordered states as the driving force for amorphization and the corresponding calculations pinpoint an optimized composition locating at an composition of Cu55Zr10Hf35, around which the driving force for metallic glass formation reaches its maximum, suggesting that the ternary Cu-Zr-Hf metallic glasses designed to have the compositions around Cu55Zr10Hf35 could be more stable than other alloys in the system. Moreover, for the Cu55Zr10Hf35 metallic glass, the Voronoi tessellation calculations reveal some interesting features of its atomic configurations and coordination polyhedra distribution. (C) 2012 American Institute of Physics. [http://dx.doi.org/10.1063/1.4766389]
10.1063-1.4879903	-1		We studied atomic and electronic structures of binary Cu-Zr metallic glasses (MGs) using combined experimental and computational methods including X-ray absorption fine structure spectroscopy, electrical resistivity, thermoelectric power (TEP) measurements, molecular dynamics (MD) simulations, and ab-initio calculations. The results of MD simulations and extended X-ray absorption fine structure analysis indicate that atomic order of Cu-Zr MGs and can be described in terms of interpenetrating icosahedral-like clusters involving five-fold symmetry. MD configurations were used as an input for calculations of theoretical electronic density of states (DOS) functions which exhibits good agreement with the experimental X-ray absorption near-edge spectra. We found no indication of minimum of DOS at Fermi energy predicted by Mott's nearly free electron (NFE) model for glass-forming alloys. The theoretical DOS was subsequently used to test Mott's model describing the temperature variation of electrical resistivity and thermoelectric power of transition metal-based MGs. We demonstrate that the measured temperature variations of electrical resistivity and TEP remain in a contradiction with this model. On the other hand, the experimental temperature dependence of electrical resistivity can be explained by incipient localization of conduction electrons. It is shown that weak localization model works up to relatively high temperatures when localization is destroyed by phonons. Our results indicate that electron transport properties of Cu-Zr MGs are dominated by localization effects rather than by electronic structure. We suggest that NFE model fails to explain a relatively high glass-forming ability of binary Cu-Zr alloys. (C) 2014 AIP Publishing LLC.
10.1063-1.4913752	2	corrosion; surface; film; electrochemical; films; spectroscopy; layer; current; solution; potential; resistance; composition; x-ray; ions; showed	We have fabricated thin films of iron nanocrystallites embedded in a copper matrix using a dual ion beam assisted deposition technique. A secondary End-Hall ion beam bombarded the iron atoms during deposition altering significantly the morphology of the films and allowing for control of the intermixing between iron and copper components. Cross-sectional transmission electron microscopy and x-ray reflectometry experiments indicated that the morphology of the films was that of iron nanocrystallites embedded in a copper matrix. Rietveld refinements of the diffraction pattern identified fcc-copper and amorphous iron. An increased amount of disorder was observed with a reduction in the amount of deposited iron from a 1: 1 Fe: Cu ratio to 0.25: 0.75 Fe: Cu ratio. Interfacial copper-iron alloys were identified by DC susceptibility experiments through their reduced T-C,T- Alloy (370, 310, and 280 K) compared with that of bulk iron (similar to 1000 K). Element specific x-ray absorption and x-ray magnetic circular dichroism experiments were performed to identify the contributions to the magnetism from the iron and the copper-iron alloy. (C) 2015 AIP Publishing LLC.
10.1063-1.4918807	13	clusters; atomic; glass; atoms; composition; dynamics; metallic; icosahedral; glasses; simulations; molecular; cu-zr; molecular dynamics; metallic glasses; structural	We investigate Cu-Zr liquid alloys using molecular dynamics simulation and well-accepted embedded atom method potentials over a wide range of chemical composition and temperature as model metallic glass-forming (GF) liquids. As with other types of GF materials, the dynamics of these complex liquids are characterized by dynamic heterogeneity in the form of transient polymeric clusters of highly mobile atoms that are composed in turn of atomic clusters exhibiting string-like cooperative motion. In accordance with the string model of relaxation, an extension of the Adam-Gibbs (AG) model, changes in the activation free energy Delta G(a) with temperature of both the Cu and Zr diffusion coefficients D, and the alpha structural relaxation time tau(alpha) can be described to a good approximation by changes in the average string length, L. In particular, we confirm that the strings are a concrete realization of the abstract cooperatively rearranging regions of AG. We also find coexisting clusters of relatively immobile atoms that exhibit predominantly icosahedral local packing rather than the low symmetry packing of mobile atoms. These two distinct types of dynamic heterogeneity are then associated with different fluid structural states. Glass-forming liquids are thus analogous to polycrystalline materials where the icosahedrally packed regions correspond to crystal grains, and the strings reside in the relatively disordered grain boundary-like regions exterior to these locally well-ordered regions. A dynamic equilibrium between localized (immobile) and wandering (mobile) particles exists in the liquid so that the dynamic heterogeneity can be considered to be type of self-assembly process. We also characterize changes in the local atomic free volume in the course of string-like atomic motion to better understand the initiation and propagation of these fluid excitations. (C) 2015 AIP Publishing LLC.
10.1063-1.4934694	7	irradiation; shear; grain; ta; deformation; size; radiation; voids; nanocrystalline; simulations; similar; void; temperature; irradiated; boundaries	Martensitic phase transformations often exhibit crackling noise response of the emitted energy. This type of behavior implies that the phase transformation proceeds through numerous events that do not exhibit any characteristic scale. On the other hand, the twinned microstructure along the phase boundary exhibits a characteristic size that is expected to affect the propagation of the phase boundary. Here, we present a statistical analysis of jerky events during martensitic transformation, induced by uniaxial compression of a single crystal Cu-Al-Ni. The results indicate that the characteristic length scale of the internal twinned microstructure dictates lm-scale displacement events of the phase boundary. At the same time, each of these lm-scale events proceeds through a multitude of smaller events that span several orders of magnitude and follow a scale-invariant power law distribution. The smaller events are associated with the local nucleation and propagation of twinning interfaces close to the phase boundary. (C) 2015 AIP Publishing LLC.
10.1063-1.4945764	-1		The thermal diffusivity of Cu-W sintered alloys microstructures is measured at room temperature at different compositions, using rear face flash experiments. The samples are synthesized with the Spark Plasma Sintering technique. The resulting microstructures are slightly porous and consist of angular nanoscale grains of tungsten with medium sphericity in a copper matrix. The tungsten particles are at the nanoscale with an average grain size of 250 nm in contrast to the copper matrix for which the average grain size lies in the range 20 mu m-30 mu m; this is large enough to avoid the grains boundary effect upon the thermal transport. The overall porosity of the microstructures lies within the range: 6% <= P <= 12%. Along with the experimental work, a predictive model describing the effective thermal conductivity of multiphasic macrostructures is proposed in order to explain the obtained experimental results. The model was developed based only on physical considerations and contains no empirical parameters; it takes into account the type of microstructure and the microstructure parameters: porosity, grain shape, grain size, and grain size distribution. The agreement between the experiments and the model is found to be excellent. (C) 2016 AIP Publishing LLC.
10.1063-1.4953676	13	clusters; atomic; glass; atoms; composition; dynamics; metallic; icosahedral; glasses; simulations; molecular; cu-zr; molecular dynamics; metallic glasses; structural	Choice of appropriate force field is one of the main concerns of any atomistic simulation that needs to be seriously considered in order to yield reliable results. Since investigations on the mechanical behavior of materials at micro/nanoscale have been becoming much more widespread, it is necessary to determine an adequate potential which accurately models the interaction of the atoms for desired applications. In this framework, reliability of multiple embedded atom method based interatomic potentials for predicting the elastic properties was investigated. Assessments were carried out for different copper, aluminum, and nickel interatomic potentials at room temperature which is considered as the most applicable case. Examined force fields for the three species were taken from online repositories of National Institute of Standards and Technology, as well as the Sandia National Laboratories, the LAMMPS database. Using molecular dynamic simulations, the three independent elastic constants, C-11, C-12, and C-44, were found for Cu, Al, and Ni cubic single crystals. Voigt-Reuss-Hill approximation was then implemented to convert elastic constants of the single crystals into isotropic polycrystalline elastic moduli including bulk modulus, shear modulus, and Young's modulus as well as Poisson's ratio. Simulation results from massive molecular dynamic were compared with available experimental data in the literature to justify the robustness of each potential for each species. Eventually, accurate interatomic potentials have been recommended for finding each of the elastic properties of the pure species. Exactitude of the elastic properties was found to be sensitive to the choice of the force fields. Those potentials that were fitted for a specific compound may not necessarily work accurately for all the existing pure species. Tabulated results in this paper might be used as a benchmark to increase assurance of using the interatomic potential that was designated for a problem. Published by AIP Publishing.
10.1063-1.4964325	-1		Main microstructural features of ultrafine-grained (UFG) polycrystalline oxygen-free copper (Cu-OF) obtained by direct and equal-channel angular hydrostatic extrusion were studied by EBSD and XRD methods. The effect of microstructure on the temperature dependences of the yield stress and strain rate sensitivity of the deforming stress was investigated using tensile and stress relaxation tests in the insufficiently studied temperature range of 4.2-300 K. Using thermal activation analysis it was established that in the range 77-200K the rate of plastic deformation is controlled by the thermally activated mechanism of crossing the forest dislocations and its empirical parameters were obtained. The experimental anomalies below 77K unaccountable by the forest crossing mechanism were explained by the inertial properties of dislocations revealed under conditions of high effective stress and low dynamic friction. The inversion of the temperature dependences of the activation volume observed above 200K was attributed to the thermally activated detachment of dislocations from local pinning centers within the grain boundaries. Published by AIP Publishing.
10.1063-1.4979125	13	clusters; atomic; glass; atoms; composition; dynamics; metallic; icosahedral; glasses; simulations; molecular; cu-zr; molecular dynamics; metallic glasses; structural	Molecular dynamics investigations of the structure and dynamics of Cu64.5Zr35.5 metallic glassforming alloy have been carried out using five different semi-empirical, many-body interaction potentials based on the Finnis-Sinclair model [M. I. Mendelev et al, J. Appl. Phys. 102, 043501 (2007) (MSK); M. I. Mendelev et al, Philos. Mag. 89, 967 (2009) (MKOSYP); L. Ward et al, e-print arXiv: 1209.0619 (2012) (WAFW)] and the embedded-atom model [Y.Q. Cheng et al, Phys. Rev. Lett. 102, 245501 (2009) (CMS) and N. Jakse et al, Phys. Rev. B 85, 174201 (2012) (JNP)]. Although the total static structure factor of the alloy for all the five interaction potentials is, in general, found to be in good agreement with the experimental results, the investigation of a local structure in terms of icosahedral short-range order reveals that the effect of the interaction potential (especially the cohesive part) on the structure of the alloy is not as trivial as it seems. For MSK and JNP potentials, the self-intermediate scattering function F-s(q, t), q-dependence of the structural relaxation time T-alpha in the low-q region, and the self-diffusion coefficient, D-s, for Cu-atoms in the alloy are in excellent agreement with the experimental results. The results for MKOSYP, CMS, and WAFW potentials deviate significantly from the experiment and suggest the dynamics of the alloy to be faster. The difference in the description of the dynamics of the alloy by different potentials is found to be due to the difference in the relevant energy scales corresponding to the temperature scales. T-alpha and D-s exhibit Arrhenius temperature dependence in the high temperature regime above the melting temperature. We also suggest that the attractive forces influence the dynamics of the liquid alloy significantly, which is against the mere perturbative role assigned to the attractive forces in the van der Waals picture of liquids that has been challenged in the recent years. As the five interaction potentials are frequently employed to study thermodynamic, mechanical, and transport properties of Cu-Zr alloys, our study also provides a suitability check for these potentials. Published by AIP Publishing.
10.1063-1.5001761	7	irradiation; shear; grain; ta; deformation; size; radiation; voids; nanocrystalline; simulations; similar; void; temperature; irradiated; boundaries	The role of the concentration and distribution of the Ta solute in a solid solution in the shock response and spall failure of a bulk nanocrystalline Cu (nc-Cu) system is investigated using large scale molecular dynamics (MD) simulations. The nanocrystalline Cu/Ta (nc-Cu/Ta) microstructures comprise a 16 nm grain size Cu matrix with distributions of 3.0%, 6.3%, and 10.0% Ta atoms either along the grain boundary or randomly in the Cu matrix. The shock response is investigated by identifying the modifications in the dynamic evolution of defect structures (dislocation nucleation and interactions), as well as the nucleation and evolution of voids. The MD simulations reveal the complex role of Ta in altering the spall behavior of the nc-Cu system. The presence of Ta is observed to improve the spall strengths of the nc-Cu system, and the strengthening behavior is achieved by limiting the capability to nucleate dislocations during shock compression and under tensile pressures. The highest values for spall strength are observed for a random distribution of Ta at a concentration of 6.3% Ta. While the increase in strength for a 16 nm grain sized nc-Cu system is reported to be similar to 8%, the role of the Ta solute is observed to be more pronounced at a larger grain size of 30 nm with a similar to 15% increase in the spall strength for randomly distributed Ta with a concentration of 6.3%. The links between the concentration and the distribution of Ta in the solid solution and the evolution of microstructures under shock loading conditions are discussed. Published by AIP Publishing.
10.1063-1.5008841	13	clusters; atomic; glass; atoms; composition; dynamics; metallic; icosahedral; glasses; simulations; molecular; cu-zr; molecular dynamics; metallic glasses; structural	The atomic structures of Cu52Zr48 and Cu45Zr48Al7 metallic glasses (MGs) have been studied by molecular dynamic simulations. The results reveal that the molar volume of the Cu45Zr48Al7 MG is smaller than that of the Cu52Zr48 MG, although the size of the Al atom is larger than that of the Cu atom, implying an enhanced atomic packing density achieved by introducing Al into the ternary MG. Bond shortening in unlike atomic pairs Zr-Al and Cu-Al is observed in the Cu45Zr48Al7 MG, which is attributed to strong interactions between Al and (Zr, Cu) atoms. Meanwhile, the atomic packing efficiency is enhanced by the minor addition of Al. Compared with the Cu52Zr48 binary MG, the potential energy of the ternary MG decreases and the glass transition temperature increases. Structural analyses indicate that more Cu- and Al-centered full icosahedral clusters emerge in the Cu45Zr48Al7 MG as some Cu atoms are substituted by Al. Furthermore, the addition of Al leads to more icosahedral medium-range orders in the ternary MG. The increase of full icosahedral clusters and the enhancement of the packing density are responsible for the improved glassforming ability of Cu45Zr48Al7. Published by AIP Publishing.
10.1063-1.5012795	-1		We investigate the relation between the strain-hardening rate and flow instability of polycrystalline Cu-OF deformed by tension at a constant rate in a liquid 3 He atmosphere. The microstructure of the ultrafine-grained crystal, obtained by the equal-channel angular hydro-extrusion method, was varied by annealing at recovery and recrystallization temperatures and was monitored by x-ray diffraction. It is shown that that the flow instability, manifesting itself as macroscopic stress serrations on the tension curve, appears at a threshold tension sufficient for activation of a dynamic recovery that leads to a decrease of the strain-hardening coefficient. We discuss the effect of grain size and the initial dislocation density on the evolution of the dislocation structure that determines the scale and the statistical properties of the flow instability in the investigated crystals at low temperature. Published by AIP Publishing.
10.1063-1.5049216	4	transformation; martensite; martensitic; phase; shape; beta; memory; shape memory; temperature; temperatures; martensitic transformation; gamma; transformation temperatures; effect; thermal	In situ neutron diffraction is used to study the strain relaxation on a single crystal and other powdered Cu-Al-Ni shape memory alloys (SMAs) around martensitic transformation temperatures. This work is focused on the analysis of the strain evolution along the temperature memory effect appearing in these alloys after partial thermal transformations. A careful study of the influence of partial cycling on the neutron diffraction spectra in the martensitic phase is presented. Two different effects are observed, the d-spacing position shift and the narrowing of various diffraction peaks, along uncompleted transformation cycles during the thermal reverse martensitic transformation. These changes are associated with the relaxation of the mechanical stresses elastically stored around the martensitic variants, due to the different self-accommodating conditions after uncompleted transformations. The evolution of the stresses is measured through the strain relaxation, which is accessible by neutron diffraction. The observed effects and the measured strain relaxations are in agreement with the predictions of the model proposed to explain this behavior in previous calorimetric studies. In addition, the thermal expansion coefficients of both martensite and austenite phases were measured. The neutron experiments have allowed a complete description of the strains during martensitic transformation, and the obtained conclusions can be extrapolated to other SMA systems. (c) 2019 Author(s).
10.1063-1.5054631	13	clusters; atomic; glass; atoms; composition; dynamics; metallic; icosahedral; glasses; simulations; molecular; cu-zr; molecular dynamics; metallic glasses; structural	Few general models representing certain classes of real glass-forming systems play a special role in computer simulations of supercooled liquid and glasses. Recently, it was shown that one of the most widely used model glassformers-the Kob-Andersen binary mixture-crystalizes in quite lengthy molecular dynamics simulations, and moreover, it is in fact a very poor glassformer at large system sizes. Thus, our understanding of crystallization stability of model glassformers is far from complete due to the fact that relatively small system sizes and short time scales have been considered so far. Here we address this issue for two embedded atom models intensively used last years in numerical studies of Cu-Zr-(Al) bulk metallic glasses. Exploring the structural evolution of Cu64.5Zr35.5 and Cu46Zr46Al8 alloys at continuous cooling and isothermal annealing, we observe that both systems nucleate in sufficiently lengthy simulations, although critical nucleation time for the latter is an order of magnitude higher than that for the former. We show that Cu64.5Zr35.5 is actually unstable to crystallization for large system sizes (N > 20 000). Both systems crystallize with the formation of tetrahedrally close packed Laves phases of different types. We argue that nucleation instability of the simulated Cu64.5Zr35.5 alloy is due to the fact that its composition is very close to that for the stable Cu2Zr compound with a C15 Laves phase structure. Published by AIP Publishing.
10.1063-1.5058205	11	glass; bulk; metallic; bulk metallic; gfa; bmg; glassy; metallic glass; ability; bulk metallic glass; amorphous; addition; crystallization; mm; glass-forming	The thermodynamic and mechanical properties of Cu46Zr46-xAl8Tix (x = 0, 1, 2, and 3 at%) bulk metallic glasses (BMGs) were investigated. The experimental results indicate that the Cu46Zr46Al8 and Cu46Zr45Al8Ti1 alloys achieve good glass formation ability (GFA), whereas that of both Cu46Zr44Al8Ti2 and Cu46Zr43Al8Ti3 alloys are weak. The thermogravimetric curve is nonlinear from the glass transition temperature to the completion of crystallization temperature and may be related to the reaction of disordered atoms and oxygen and nitrogen atoms. The Cu46Zr45Al8Ti1 BMG with the work-hardening ability in these alloys has a large yield strength of 1870 MPa and a fracture strength of 2060 MPa. The average incubation time of the serrated flow in the elastic-plastic stage with the high work-hardening index is 1.3706 s, which is higher than that of the plastic deformation stage (0.9398 s) with the low work-hardening index. The nonlinear thermogravimetric curve of the supercooled liquid region and the average incubation time of the serrated flow are crucial to further understand the oxidizability and nitriding capacity of the disordered atoms and the mechanism of plastic strain in the metallic glass field. (C) 2018 Author(s).
10.1063-1.5090424	7	irradiation; shear; grain; ta; deformation; size; radiation; voids; nanocrystalline; simulations; similar; void; temperature; irradiated; boundaries	Radiation-induced hardening by precipitates, which essentially has a dislocation pinning effect, is a major issue in nuclear reactor pressure vessels research . In this study, simulations of interactions between edge dislocations and copper precipitates are conducted as an example to investigate size-dependent pinning effects. Using molecular dynamics simulations, we discover a new two-stage mechanism that includes the processes of reorientations and atomistic collective migrations during the interactions. Both of these result in a weakening of the pinning effect on dislocations when the phase transition occurs in copper precipitates, which can be reflected in the decrease of the critical shear stress in stress and strain curves. Our studies considered the atomistic arrangement of the obstacle during the interaction, which constructively provide a new perspective for research studies of dislocation-obstacle pinning interaction and offer a more comprehensive estimation on the pinning strength of dislocations. Published under license by AIP Publishing.
10.1063-1.5119150	7	irradiation; shear; grain; ta; deformation; size; radiation; voids; nanocrystalline; simulations; similar; void; temperature; irradiated; boundaries	Grain boundaries in nanocrystalline (NC) materials are important as they control the microstructural evolution and act as both sinks and sources for dislocation activities. In order to enhance the absorption of dislocations and restrict the crack nucleation and growth, the conventional grain boundaries can be substituted with amorphous intergranular films (AIFs). In the present atomistic study, we investigated the deformation mechanism of bicrystals and NC Cu specimens with AIF under dynamic and static loading conditions with a particular focus on the influence of grain sizes (3 nm-17 nm) and AIF thicknesses (0.5 nm-1.5 nm). We found that the presence of AIF homogenized the interfacial energy irrespective of the grain orientations and decreased its overall value, which posed a strong effect on the strength of the metallic system. In addition, we observed a shift of the deformation mechanism from that dominated by dislocations to interfacial activities due to the presence of AIF as the grain size or AIF thickness changed. Finally, results from high-temperature creep deformation showed that the NC Cu with AIF had excellent thermal stability despite its small grain size.
10.1063-1.5119373	-1		A study of a transition from conventional multicomponent alloys to high-entropy alloys (HEAs) is important both for understanding the formation of HEAs and for proper evaluation of their potential with respect to that of conventional alloys. We report the main result of such a study performed on (TiZrNbNi)(1-x)Cu-x metallic glasses (MG) over a broad concentration range x <= 0.52 encompassing both high-entropy-MGs and Cu-based MGs. A comprehensive study of the composition, homogeneity, thermal stability, atomic structure, electronic structure, and magnetic susceptibility of 11 alloys has been performed. Thermal analysis revealed a rather weak variation of thermal parameters and glass forming ability with x. The study of the atomic structure showed a linear variation of average interatomic distances and atomic volumes close to those predicted by Vegard's law. The coordination numbers and atomic packing fractions were constant throughout the explored concentration range. The electronic density of states (DOS) showed a split-band structure with DOS close to the Fermi level dominated with d-states of Ti, Zr, and Nb. Accordingly, magnetic susceptibility decreased linearly with x and extrapolated to that of Cu. Thus, the studied alloys show ideal solution behavior similar to that of binary Cu-Ti, Zr, and Hf MGs. The results are compared with those for (TiZrNbCu)(1-x)Ni-x MGs and (CrMnFeCo)(1-x)Ni-x alloys and their impact on understanding the transition from high-entropy-MGs to conventional MGs with the same composition is briefly discussed. Published under license by AIP Publishing.
10.1063-1.5131500	13	clusters; atomic; glass; atoms; composition; dynamics; metallic; icosahedral; glasses; simulations; molecular; cu-zr; molecular dynamics; metallic glasses; structural	The fast increase in available computation power allowed us to decrease the cooling rate in molecular dynamics (MD) simulation of vitrification by several orders of magnitude. While the reliability of the MD simulation should obviously benefit from this increase in the computational power, in some cases, it led to unexpected results. In particular, Ryltsev et al [J. Chem. Phys. 149, 164502 (2018)] found that the most popular potentials for the Cu-Zr and Cu-Zr-Al alloys from Mendelev et al [Philos. Mag. 89, 967 (2009)] and Cheng et al [Phys. Rev. Lett. 102, 245501 (2009)] do not actually describe good glass forming systems but in contradiction with experiment predict rather fast crystallization of the Cu64.5Zr35.5 alloy which is the well-known example of bulk metallic glasses. In this paper, we present a new Cu-Zr semiempirical potential suitable to simulate vitrification. No crystal nucleation was observed in MD simulation using this potential in the concentration range from 75% to 5% of Zr. Since the new potential leads to about the same liquid structure and viscosity as the Cu-Zr potential from Mendelev et al [Philos. Mag. 89, 967 (2009)] which failed to describe the good glass formability, our study clearly shows that no reliable conclusions about the glass formability can be deduced based solely on the analysis of the liquid properties and a nucleation/crystal growth study should be performed to address this question. Published under license by AIP Publishing.
10.1063-1.5131645	-1		Metallic glasses have many fascinating properties such as theoretical-limit approaching strength, high wear and corrosion resistance, and extremely smooth surfaces enabling high-performance thin film diodes. Copper-based metallic glasses are of particular interest due to the low cost and attractive characteristics of the base element, but the copper-based metallic glasses known to date rely on rare-earth or precious metals that have limited supplies and relatively high cost, in order to achieve good glass-forming ability. Here, we report our discovery of a series of rare-earth and precious-metal free copper-based metallic glasses formulated as Cu46Zr47-xHfxAl7 (8 <= x <= 20, at. %), which possess superior glass-forming ability and processability. Fully amorphous ingots with a large cross section of 15 (all x) to 28.5mm (x=13.5) diameter can be readily produced by a simple water quenching method. The Cu46Zr33.5Hf13.5Al7 alloy, in particular, presents the highest glass-forming ability and processability of all known copper-based metallic glasses. The adjustable Hf content in the composition offers a range of physical properties (e.g., density) that can be chosen based on applications. We also discuss the physical origin of the superior glass-forming ability and processability in these copper-based metallic glasses.
10.1063-5.0002784	-1		The glass forming ability (GFA) of Cu-Zr alloys has been still ambiguous, due to incomplete or lacking thermophysical properties of Cu-Zr liquids in supercooled and stable states, although tremendous effort has been devoted. We provide here the comprehensive thermophysical properties of Cu-Zr liquids, such as undercoolability, density, viscosity, fusion enthalpy, temperature-time-transformation (TTT) diagram, and crystal-liquid interfacial free energy. Three compositions, Cu64Zr36, Cu56Zr44, and Cu50Zr50, show distinctive anomalies in undercoolability, nose time in TTT, and crystal-liquid interfacial free energy, but not in density and viscosity in supercooled and stable liquid states. The anomalies reflect that the GFA is dominantly governed by thermodynamics rather than kinetics in these bulk metallic glasses (BMGs). In addition, we find that positions of nose temperatures in the TTT curves are below 1/2 (T-g + T-l), which implies unequal contribution of thermodynamics and kinetics. We discuss that empirical GFA parameters cannot explain the glass formation of Cu-Zr alloys due to the unequal contribution, and the Turnbull GFA criterion (T-rg = T-g/T-l) is valid for the equal contribution of the two effects. The present experimental findings shed light on the ongoing debate about the GFA criterion of Cu-Zr BMGs.
10.1063-5.0004320	-1		Understanding the role of processing parameters on the atomic-level deformation mechanism and structural evolution during an accumulative roll bonding process is a necessity in scaling-up the production of metallic nanolaminates. In this study, we have developed a novel atomistic model of nano-rolling to investigate the effect of roller speed and temperature on the deformation behavior of Cu-Zr nanolaminate. The model takes both the compressive and the shear forces into consideration during the rolling process, making it efficient in reproducing the actual deformation mechanisms. Results from the mobility analysis have shown that the final velocity of the rolled specimen obtained from the simulation is close to the theoretical value. The phenomenon of texture evolution is also analyzed through orientation scatter analysis, where it is revealed that increasing the roller speed facilitates the formation of low angle grain boundaries and twins at lower temperatures. However, texture weakening of the rolled specimen has been observed at elevated temperatures due to the increase in fine grained equiaxed structures. Concurrently, the roller speed and temperature dependent deformation mechanism of the Zr-layer is also captured through atomic displacement analysis, which shows the formation of a smooth and wavy Zr-layer. Through Voronoi analysis, it is revealed that the wavy profile of the Zr-layer has a direct influence on the formation of metallic glass at the Cu-Zr interface as a higher number of icosahedral clusters are observed in specimens with a wavy Zr-layer.
10.1063-5.0006859	4	transformation; martensite; martensitic; phase; shape; beta; memory; shape memory; temperature; temperatures; martensitic transformation; gamma; transformation temperatures; effect; thermal	We have tracked the dynamics of the martensitic transformation in a Cu-Al-Ni single crystal by means of acoustic emission and infrared imaging techniques. A Fourier equation-based post-processing of temperature maps has enabled us to reveal the inhomogeneous and discontinuous character of heat power sources and sinks during the transition. A good correlation between the dynamics of thermal and mechanical energy release has been evidenced. It has also been shown that the merging of martensitic interfaces results in an enhanced heat absorption.
10.1063-5.0049522	-1		Secondary electron yield (SEY) is relevant for widely used characterization methods (e.g., secondary electron spectroscopy and electron microscopy) and materials applications (e.g., multipactor effect). Key quantities necessary for understanding the physics of electron transport in materials and simulation of SEY are electron mean free paths (MFPs). This paper explores the impact of alloying on MFPs and SEY for Cu-Ni, Cu-Zn, and Mo-Li alloys relative to their component metals Cu, Ni, Zn, Mo, and Li. Density functional theory calculations yield density of states, Fermi energy, work function, and frequency- and momentum-dependent energy loss function. These material properties were used to calculate MFPs and Monte Carlo simulations were performed to obtain energy dependent SEY for the alloys as well for the component metals. The results show that MFPs and SEYs of the studied alloys lie between those of component pure elements but are not a simple composition weighted average. Detailed analysis of the secondary electron generation and emission process shows that the changes in the SEY of alloys relative to the SEY of their component metals depend on the changes in both electronic structure and dielectric properties of the material.
10.1063-5.0066525	4	transformation; martensite; martensitic; phase; shape; beta; memory; shape memory; temperature; temperatures; martensitic transformation; gamma; transformation temperatures; effect; thermal	The physics behind the cooling process occurring in an elastocaloric Cu-Al-Ni wire during the martensite to austenite transition after stress release is studied. A previous experiment using infrared imaging determined the temperature map evolution of the sample surface and obtained the qualitative evolution of heat sinks by reversing the Fourier heat equation. The results were only qualitative due to the data smoothing algorithm that was used to correct the experimental noise. We analyze the original data by using a more appropriate Gaussian filter to reject the noise without smoothing the sharp martensite-austenite interfaces. Results show a much better spatial resolution that enables us to obtain new physical variables characterizing the discontinuous, avalanche-like, cooling process: the sink width, the sink cooling power, and the sink velocity.
10.1063-5.0084266	-1		Operation of normal conducting accelerator structures at high accelerating gradients is beneficial for many accelerator applications in basic science, industry, medicine, and National Security. RF breakdown is the major factor that limits the achievable accelerating gradients. Previous experiments on copper (Cu) have demonstrated that RF breakdown probability can be significantly decreased by hardening the material and alloying Cu with solutes such as silver (Ag). In this paper, we propose a figure-of-merit (FOM) that characterizes the ability of Cu alloys to withstand high-gradients. The FOM represents a trade-off between hardening through solid solution strengthening and the additional thermal stress induced by incremental RF pulse heating resulting from changes in electronic properties induced by alloying. We performed high-throughput ab initio calculations and computed the FOM for a large number of binary Cu alloys. Several promising candidate alloys for high-gradient accelerating structures were identified, such as CuAg, CuCd, CuHg, CuAu, CuIn, and CuMg. CuAg alloys have previously exhibited low RF breakdown rates in experiments. The results provide guidance for selecting alloys for the future high-gradient normal conducting accelerating structures operating at very high gradients. Published under an exclusive license by AIP Publishing.
10.1063-5.0086445	-1		The dynamic tensile spall failure of additively manufactured (AM) two-layered bimetallic GRCop-84-Inconel (R) 625 alloys, with planar and slanted interfaces, is investigated using uniaxial-strain plate-impact gas-gun experiments. Multiple photon Doppler velocimetry (PDV) is used to monitor the back (free) surface velocity profiles and to determine the influence of the interface geometry on the spall failure. Micrographs of cross sections of recovered impacted samples reveal failure along the interface as well as in-material regions. Spall strengths determined from pull-back signals captured with the use of the multiple PDV probes illustrate different location-specific values for the same sample, corresponding to failure occurring in Inconel (R) 625, or GRCop-84, or along their interface, depending on the geometry of the interface. The results obtained from the experiments employing multiple PDV probes correlated with microstructural observations of cross sections of recovered impacted samples, provide a useful method for determining the complex spall failure response of two-layered bimetallic alloys, including the differentiation of the response of the respective alloy materials relative to that of the interface, in the same experiment. Published under an exclusive license by AIP Publishing.
10.1063-5.0096880	-1		The generation of high magnetic fields requires materials with high electric conductivity and good strength properties. Cu/Nb composites are considered to be good candidates for this purpose. In this work, we aim to predict, from theory, the dependence of electric conductivity on the microstructure, most notably on the layer thickness and grain sizes. We also conducted experiments to calibrate and validate our simulations. Bimetal interfaces and grain boundaries are confirmed to have the largest impact on conductivity in this composite material. In this approach, a distribution of the layer thickness is accounted for in order to better model the experimentally observed microstructure. Because layer thicknesses below the mean free path of Cu significantly degrade the conductivity, an average layer thickness larger than expected may be needed to meet conductivity requirements in order to minimize these smaller layers in the distribution. We also investigate the effect of variations in volume fraction of Nb and temperature on the material's conductivity. (C) 2022 Author(s). All article content, except where otherwise noted, is licensed under a Creative Commons Attribution (CC BY) license (http://creativecommons.org/licenses/by/4.0/).
10.1063-5.0097023	7	irradiation; shear; grain; ta; deformation; size; radiation; voids; nanocrystalline; simulations; similar; void; temperature; irradiated; boundaries	The glass formation ability of an alloy depends on two competing processes: glass-transition, on one hand, and crystal nucleation and growth, on the other hand. While these phenomena have been widely studied before in nearly equiatomic Cu-Zr alloys, studies are lacking for solute/solvent-rich ones. In the present work, molecular dynamics simulations show that the addition of a small amount of Zr (1-10 at. %) to Cu drastically increases the incubation time and slows down crystal growth, thus, leading to an improved glass forming ability. The crystal nucleation and growth processes of a competing face-centered cubic (FCC) Cu crystalline phase are analyzed in detail. In particular, the values of the critical cooling rate, incubation period for crystallization, and growth rate of FCC Cu crystals in these Cu-rich alloys are obtained. The growth of a supersaturated FCC Cu solid solution is found to be polymorphic at the interface (except for alloys with 9 and 10 at. % Zr) though a Zr concentration gradient is observed within growing crystals at high enough Zr content. The crystal growth rate before crystal impingement is nearly constant in all alloys, though it decreases exponentially with the Zr content. Crystallization kinetics are also analyzed within the existing theories and compared with the experimental values available in the literature. (c) 2022 Author(s). All article content, except where otherwise noted, is licensed under a Creative Commons Attribution (CC BY) license(http://creativecommons.org/licenses/by/4.0/).
10.1063-5.0123681	-1		The crystallization temperature of deeply undercooled Cu-Ge alloy melts is repeatedly measured. A statistical analysis is applied on the undercooling distributions obtained from nine different compositions, ranging from the pure semimetal (Ge) to the pure metal (Cu). By considering each undercooling distribution as an inhomogeneous Poisson process, the nucleation rates for every composition are calculated. The Thompson-Spaepen model for homogeneous nucleation in binary alloys is applied, enabling the estimation of nucleation parameters, such as kinetic pre-factors and interfacial energies, as a function of composition. Furthermore, the Turnbull coefficient alpha, a dimensionless solid-liquid interfacial energy constant, is also calculated as a function of alloy constitution, suggesting a dependence on the liquid composition. The composition-dependent changes of alpha are of considerable importance, since the alpha is originally defined for pure systems as a quantity dependent on crystal structure, and is nevertheless used for describing nucleation kinetics of binary and glass forming multi-component alloy systems. Published under an exclusive license by AIP Publishing.
10.1063-5.0147438	-1		To generate long-duration pulsed magnetic fields with low energy consumption, we present a practical setup that implements an electromagnet made of high-purity copper (99.9999%). The resistance of the high-purity copper coil decreases from 171 m Omega (300 K) to 19.3 m Omega (77.3 K) and to below similar to 0.15 m Omega (4.2 K), indicating a high residual resistance ratio of 1140 and a substantial reduction in Joule loss at low temperature. Using a 157.5 F electric-double-layer-capacitor bank with a charged voltage of 100 V, a pulsed magnetic field of 19.8 T with a total field duration of more than 1 s is generated. The field strength of the liquid helium-cooled high-purity copper coil is approximately double that of a liquid nitrogen-cooled one. The low resistance of the coil and the resultant low Joule heating effect explain the improvements in accessible field strength . The low electric energy used for field generation warrants further investigation on low-impedance pulsed magnets consisting of high-purity metals.
10.1063-5.0151827	-1		Dynamic recrystallization (DRX) is a widely observed phenomenon in metals and alloys during hot deformation. However, a comprehensive understanding of the mechanisms and microstructural evolution of DRX at extremely high strain rates is still lacking. In this study, we present a new mechanism, termed planar fault-assisted dynamic recrystallization (pfDRX), which was identified by simulating the cold spray of copper (Cu) at high strain rates using molecular dynamics. Our findings indicate that planar faults, such as nanotwins, stacking faults, hexagonal close-packed martensites, and local slip, play a dominant role in the initial deformation of Cu during high velocity impacts in columnar-like quasi-two-dimensional samples where deformations are primarily limited to in-plane slip. Furthermore, subsequent slip events interact with pre-existing planar faults, triggering the formation of new grains via a common interaction-amorphization-nucleation-growth pfDRX mechanism. We systematically varied temperature and strain rates to determine the optimal conditions for pfDRX. This study offers valuable insights into novel DRX mechanisms in face-centered cubic metals at high strain rates and provides guidance for future experimental research .
10.1063-5.0209894	-1		We report here the effect of the magnetic field on plasma parameters and the surface structuring of the Cu alloy after fs laser irradiation. A Ti:Sapphire (800 nm, 35 fs, 1 KHz) laser is employed at various irradiances (0.011-0.117 PW/cm(2)) to generate plasma. A Transvers Magnetic Field (TMF) of strength 1.1 T is employed for plasma confinement. All the measurements were performed with and without TMF. The Cu plasma parameters, i.e., excitation temperature (T-exc) and electron number sensity (n(e)), determined by laser-induced breakdown spectroscopy analysis, are higher in the presence of TMF. This magnetic field confinement of Cu plasma was studied analytically by evaluating thermal beta (beta(t)), directional beta (beta(d)), confinement radius (R-b), and diffusion time (t(d)). To correlate Cu-alloy plasma parameters with surface modifications, field emission scanning electron microscope analysis is performed. It reveals the formation of low-spatial-frequency laser-induced periodic surface structures (LIPSSs) and high-spatial-frequency LIPSSs, along with agglomers and nano-rims formation. Distinct and well-defined structures are observed in the presence of a magnetic field. It is concluded that controlled surface structuring can be achieved through magnetic confinement, which enhances key plasma parameters. The technique has the potential for enhancing the fabrication of nano-gratings and field emitters, where spatial uniformity is critically important.
10.1063-5.0253150	-1		Femtosecond laser-driven shock waves exhibit characteristic features that form distinctive microstructures not formed by plate impacts or nanosecond laser-driven shock waves. A key to understanding this phenomenon is understanding the lattice behavior inside the shock front, which is the boundary between the ambient and shock compression states. However, direct measurements of the lattice spacing inside a femtosecond laser-driven shock front have not yet been performed. Here, we report in situ measurements of lattice spacing using x-ray free electron laser diffraction with a pulse width of <10 fs during the shock rise in single-crystal copper irradiated directly in air with a femtosecond laser pulse on the order of 10(14) W/cm(2) at a pulse width of 101 fs. The lattice spacing of the femtosecond laser-irradiated single-crystal Cu (002) plane starts to compress 6.3 ps after femtosecond laser irradiation. It takes 15.7 ps for the plane to reach peak compression, at which point the compressive elastic strain is 24.3%. Therefore, the shock front was found to form at an elastic compressive strain rate of 1.55 x 10(10)/s in this shock-driving situation. It is suggested that the initiation of plasticity under such ultrafast deformation at the most elastic compression is based on both dislocation multiplication and dislocation generation mechanisms.
10.1063-5.0253997	-1		In this work, we evaluated the ability of three numerical methods to predict the phase formation in Cu-Zn binary and Cu-Ti-Zn ternary alloy thin films deposited by DC-magnetron sputter deposition. Molecular dynamics (MD) simulations were carried out to simulate the growth of the alloy film and study the organization at the atomic level. A Machine Learning (ML) approach trained with a recently published bulk HEA (high-entropy alloy) database was used to determine the presence of an amorphous phase, solid solutions, or/and intermetallics. Finally, CALPHAD (CALculation of PHAse Diagrams) thermodynamic modeling allows one to simulate the phase diagrams. Crystalline phases formed in experimental films were investigated by grazing incidence x-ray diffraction (GIXRD). Comparison with CALPHAD results highlights that for pure Ti or binary Cu-Zn films, the thermodynamically stable phases are formed in the films. Less agreement was found at low or high percentage of Ti introduced in the Cu-Zn system, and drastic differences were observed for elemental compositions close to equimolarity. In those cases, the out of equilibrium nature of the magnetron sputtering deposition technique is evidenced. The very limited agreement between the GIXRD and ML approach is explained by the available database, which is exclusively based on bulk alloys. Elemental composition of the alloy does not itself determine the stabilized phases: elaboration techniques are to be taken into account too. MD simulations bring information on a possible segregation of the Zn element to the surface and grain boundaries. A very good agreement is evidenced between the calculated and experimental diffraction patterns.
10.1063-5.0259893	-1		It is an inevitable consequence of materials being exposed to elevated levels of particles and heats that they will experience various forms of damage, resulting in changes in their macroscopic properties, including the heat transport characteristics of the material. The effects of temperature, irradiation damage, and tensile strain on the lattice thermal conductivity of Cu-Ni alloys were investigated using the equilibrium molecular dynamics method. The microphysical mechanism of the variation of the lattice thermal conductivity of Cu-Ni alloys is revealed in terms of the density of phonon states, the variation of phase components, and the type, number, and distribution of defects. The results show that the lattice thermal conductivity of Cu-Ni alloys changes with increasing Ni content, which is due to enhanced phonon scattering as a result of poor mass and lattice disorder. The phonon-phonon scattering is exacerbated with increasing temperature, which further leads to a change in the thermal conductivity of the alloys. Compared to pre-irradiation Cu-Ni alloys, the type, quantity, and distribution of defects produced by irradiation will significantly affect the lattice thermal conductivity of Cu-Ni alloys. The tensile strain introduces more phonon scattering centers (e.g., dislocations, grain boundaries, etc.), which further reduces the heat transfer efficiency. This study provides valuable insights into the interplay between alloy composition, understanding of irradiation effects and heat transport properties under mechanical deformation, and contributes to a fundamental understanding of heat transport in disordered metallic systems. (c) 2025 Author(s). All article content, except where otherwise noted, is licensed under a Creative Commons Attribution-NonCommercial-NoDerivs 4.0 International (CC BY-NC-ND) license (https://creativecommons.org/licenses/by-nc-nd/4.0/).
10.1063-5.0270838	-1		Plate-impact experiments were conducted on Cu-Ti alloy (with 4.8 wt. % Ti) samples to determine its dynamic strength properties, e.g., yield strength and spall strength, under high strain rate-loading conditions. The as-received samples were subjected to microscopic analysis through x-ray diffraction and electron back scattering diffraction (EBSD) measurements before using in experiments. In a series of planar shock loading experiments carried out at different impact speeds, the shock stress and free-surface velocity history (FSVH) were measured and utilized to generate the Hugoniot data of the Cu-Ti alloy up to 18 GPa. The analysis of FSVH yielded the Hugoniot elastic limit (HEL) varying from 1.49 to 2.12 GPa, following an increasing trend up to 7.35 GPa. The dynamic yield strength averaged to be similar to 0.97 GPa, which is 18% higher than the quasi-static value of 0.82 GPa. The spall strength as a function of shock pressure was found in the range of 1.95-2.71 GPa with a slightly increasing trend up to a pressure of 7.35 GPa and a monotonically decreasing trend thereafter. The analysis of EBSD patterns of samples recovered from peak shock stress of 7.35 and 15.38 GPa indicated a significant increase in fracture facilitating deformation twins together with the high-angle grain boundaries at 15.38 GPa, thus resulting in reduced spall strength . Furthermore, microstructural observations revealed progressive grain refinement, enhanced plastic deformation, and dynamic recovery with increasing shock pressure. The Hugoniot, HEL, and spall strength have been compared with those of unalloyed Cu available in the literature.
10.1080-00084433.2016.1247129	16	wear; composite; composites; powders; milling; particles; powder; wt; sliding; friction; hardness; matrix; mechanical; surface; properties	The present work compares the properties of the Cu-TiB2 composites prepared by varying the mechanical milling conditions. The Cu-TiB2 composites were processed using Cu-TiB2 powders combined milling, a powder mixture consisting of separately milled Cu & TiB2 and a powder mixture prepared by the combination of separate and combined milling. The hardness and flexural strength of the combined milled powders were found to be maximum, despite of their lower sintered density. The separately milled powders achieved excellent electrical properties combined with moderate hardness and flexural strength . The properties of composites processed using the combination of separate and combined milling laid in between the two conditions of combined and separate milling.
10.1080-00084433.2017.1403073	2	corrosion; surface; film; electrochemical; films; spectroscopy; layer; current; solution; potential; resistance; composition; x-ray; ions; showed	Cu-10Ni alloy has an outstanding resistance to corrosion in seawater due to formation of protective Cu2O film. However, in presence of S2- ions, it suffers accelerated corrosion. The present paper investigates the corrosion behaviour of Cu-10Ni, Cu-10Ni-6Zn and Cu-10Ni-12Zn alloys using weight loss, electrochemical impedance spectroscopy and potentiodynamic polarisation technique. The experiments were performed in clean seawater and sulphide contaminated seawater. The Cu-10Ni-6Zn and Cu-10Ni-12Zn alloys were found to exhibit lower corrosion rate than Cu-10Ni alloy in clean and sulphide contaminated seawater. Lower corrosion rate of Zn containing alloys in clean seawater is attributed to the incorporation of Zn2+ ions in Cu2O lattice. Lower corrosion rate of Zn containing alloys sulphide contaminated seawater is attributed to formation of ZnS in the film.
10.1080-00084433.2023.2175955	-1		In this work, the microstructural evolution and common defects of Cu-Ag (0.075 wt%) alloy during continuous extrusion molding (CONFORM) were characterised and analyzed. The microstructures at different positions inside the CONFORM cavity and the exit were comprehensively revealed by combining electron backscatter imaging, electron backscatter diffraction, energy dispersive spectroscopy, and finite element modelling. The results showed that the temperature of the cavity was much higher than the recrystallization temperature of the Cu-Ag alloy. However, both deformation and recrystallization structures were observed in the cavity due to the extremely high extrusion rate. Owing to the different speeds of the extrusion and coining rollers, the friction forces on the upper and lower surfaces of the Cu-Ag bar were different, resulting in shear stress. Such shear stress leads to a slight difference in grain size between the upper and lower layers of the extruded wires. The existence of low-angle boundaries caused by grain fragmentation and dislocation arrangement accelerates the dynamic recrystallization process in the upper layer and the residual strain on the upper surface of the wire was larger than that in the middle and lower layers.
10.1080-00084433.2023.2205768	-1		A copper 0.65 wt-% magnesium alloy was oxidised in the air from 700 to 950 degrees C, in a TGA/DTA apparatus and a muffle furnace. The alloy oxidises following the parabolic rate law. Oxidation of this material is diffusion-controlled. A second experimental was conducted to determine the extent of oxidation by measuring the thickness of the internal oxidation layer. The amount of magnesium added to the copper prevents its oxidation up to 800 degrees C. At higher temperatures, more magnesium is needed to slow down the rate of oxidation of copper. Furthermore, the oxidation layer of the Mg-Cu alloy can be estimated using a kinetic model designed by us for alloy oxidation.
10.1080-00150193.2018.1449450	-1		C70250 copper alloy rod billets with O20mm were prepared by a self-developed temperature controlled mold continuous casting (TCMCC) technique. The evolution of microstructure and mechanical properties of rod billet at different casting speeds and mold temperatures was investigated. The influence mechanism of different process parameters on microstructure and properties of rod billet was revealed. The results show that C70250 copper alloy rod billets with / \ shape inclined columnar grains and equiaxed grains mixed structure are prepared when the melt temperature is 1200 degrees C, the cooling water temperature is 20 degrees C, cooling water flow rate is 400Lh(-1), the casting speed is 10 approximate to 50mm/min and the mold temperature is 1050 approximate to 1090 degrees C. When the casting speed increases from 10mm/min to 50mm/min, the average grain size of columnar grains increases from 0.72mm to 1.43mm gradually, and the number of equiaxed grains decreases gradually. Besides, the tensile strength of the rod billet decreases from 305MPa to 252MPa, and the elongation increases from 33.5% to 42.1%. When the mold temperature increases from 1050 degrees C to 1090 degrees C, the average grain diameter of columnar grains increases from 0.72mm to 1.43mm gradually, and the number of equiaxed grains reduces gradually. Besides, the tensile strength of the rod billet decreases from 326MPa to 275MPa, and the elongation increases from 31.2% to 41.2%. With the increase of casting speed and mold temperature, the number of nucleation on the mold wall reduces, and the average grain diameter of columnar grains increases, which reduces the number of grain boundaries per unit area. Therefore, the tensile strength of C70250 copper alloy increases and the elongation decreases.
10.1080-00202967.2003.11871490	2	corrosion; surface; film; electrochemical; films; spectroscopy; layer; current; solution; potential; resistance; composition; x-ray; ions; showed	Recent investigations on nanostructured metal multilayers have shown that interfaces between each bi-layer can affect the properties of a multilayer Transient current and potential data after the application of a potential step or a current step, respectively, during the codeposition of copper and nickel from a citrate electrolyte have been investigated. It has been found that on the application of a current step only copper is reduced at first, followed by the deposition of a copper-nickel alloy. Once the current is switched off nickel (or a nickel-rich) alloy is dissolved from the deposit due to displacement by copper Transient potentials and steady-state polarisation data can be used to determine the amount of nickel dissolved from a deposit.
10.1080-00202967.2019.1644764	2	corrosion; surface; film; electrochemical; films; spectroscopy; layer; current; solution; potential; resistance; composition; x-ray; ions; showed	Copper-rich Cu-Zn alloy coatings were successfully codeposited on steel substrates using glutamate-based electrolytes at room temperature. The effect of various proportions of Cu2+ and Zn2+ ions in the electrolyte on the current efficiency and on the metal content in deposited alloy was studied. It was found that the current efficiency was 53-99%, depending on the operating conditions and the bath composition, which could be considered high, in comparison with those of cyanide (75%) and citrate baths (70-80%). On the other hand, the Cu content in the deposit ranged from 20% to 98%. The electrochemical kinetic data confirm that addition of monosodium glutamate (MSG) to the plating bath increases i(o) and decreases the Tafel slope while the transfer coefficient is invariant. The relative invariance of alpha(c), observed for increasing glutamate ion concentrations, suggests that the Cu-Zn alloy electrodeposition pathway is not affected by the presence of glutamate. The data of throwing power, throwing index and Wagner number are consistent with each other.
10.1080-00219592.2023.2211117	0	solidification; phase; magnetic; magnetic field; undercooling; field; liquid; separation; peritectic; immiscible; cu-; dendrite; phase separation; microstructure; primary	An electromagnetic levitation technique superimposed with a static magnetic field was used to investigate the effects of the convection and cooling rate of levitated molten Cu80Fe20 alloy on the size and morphology of induced phase separation structures formed during undercooling. The obtained results were compared to our previous works on the Cu80Co20 alloy, in terms of the size and morphology of the phase-separated structures of dispersed Fe-rich phases. It was revealed that the Sauter mean diameter in the two systems followed the same trend, although the Co-rich phases were larger in size than the Fe-rich ones at higher static magnetic fields. Under a larger static magnetic field, the separated Co-rich phases in Cu-Co alloys had an elongated shape along the direction of the static magnetic field, while the Fe-rich phases in Cu-Fe remained almost spherical in shape. This difference in shapes was attributed to physical properties, particularly their magnetic susceptibility.
10.1080-00319104.2012.682258	-1		The structure of Cu x Ge1 x (x=0.5; 0.54; 0.57; 0.6; 0.62; 0.635; 0.65; 0.67; 0.70; 0.73; 0.767) molten alloys has been studied by means of the X-ray diffraction method. Structure factors and pair correlation functions have been analysed at three temperatures (T L+5K; T L+50K; T L+100K). The melts are shown to reveal the transition of structure based on Ge-clusters into one based on Cu3Ge intermetallic, when Cu content increases. This transition occurs in the concentration region around the eutectic point.
10.1080-00319104.2013.830221	-1		Molecular dynamics simulations have been performed to explore interface growth of liquid Cu50Ni50 alloy by using an embedded atom potential, namely due to Zhou. The simulated melting temperature is 1585K in agreement well with the experimental value of 1600K. The calculated interface velocity increases with decreasing temperature ranging from 1585K to 1100K, where the calculated values are a little higher than the experimental ones at higher temperatures, and in agreement with the experimental ones at lower temperatures; while the calculated interface velocity decreases with decreasing temperature lower than 1100K. The activation energy of atom is 0.0048eV, almost close to zero under deep undercoolings, although the crystal growth still proceeds with the speed ranging from 50ms(-1) to 10ms(-1). The crystal growth of Cu50Ni50 is not controlled by diffusion mechanism under deep undercoolings.
10.1080-00319104.2016.1233184	-1		We investigated of the kinematic viscosity of liquid Cu-Sn alloys upon heating and subsequent cooling by the method of the oscillating cylinder. For the liquids alloys Cu75Sn25, Cu50Sn50, Cu48Sn52, Cu32Sn68, and Cu17Sn83, the temperature dependencies of the viscosity upon heating deviate from the Arrhenius relation. The temperature dependencies of viscosity show the Arrhenius-like behaviour upon cooling for all investigated alloys. A discrepancy between the temperature dependencies of viscosity obtained upon heating and cooling arised. We built the concentration dependences of the kinematic viscosity of liquid Cu-Sn alloys upon cooling. The increase of the values of viscosity and activation energy of viscous flow in the concentration range corresponding to the existence of intermetallic compounds Cu3Sn in the solid state was observed. These results were qualitatively interpreted using the concept of microheterogeneities of liquid alloys.
10.1080-00325899.2016.1277095	16	wear; composite; composites; powders; milling; particles; powder; wt; sliding; friction; hardness; matrix; mechanical; surface; properties	Water atomised copper powders (AT-Cu) have been processed by continuous and interrupted mechanical milling (MM) for different milling times. For continuous cycle the powders are subjected first to a severe flattening process and then to an intense welding phenomenon. In the case of interrupted cycle MM behaviour proceeds with an intense fracturing process. By quantitative X-ray-diffraction analysis the interrupted cycle shows constantly a delay of the microstructure evolution with all the phenomena shifted at longer milling time. For both types of cycle crystalline size decreases down to 20 nm. After 6000 min of interrupted MM the formation of Cu2O has been revealed and a strong dependency between oxygen content and microstructural parameter has been attested analysing the variations of lattice parameter and lattice strain. When the interstitial oxygen atoms lose their Cottrell locking action dislocation annihilation occurs leading to a reduction of dislocation density and lattice strain.
10.1080-00325899.2017.1286749	-1		In the field of the deformation process modelling, constitutive equations tend to be utilised as a calculation basis for the estimation of the materials' flow responses. This holds also for powder metallurgy products. Hence, in this study, the flow behaviour of sintered Cu-28Zn pre-alloyed powder compacts was investigated by a collection of isothermal hot compression tests in the temperature range of 550-850 degrees C at strain rates of 0.001, 0.01, 0.1 and 0.5 s(-1) up to the true strain of 0.6. For the sintered part with a predefined porosity of 9.4%, the impacts of the temperature and strain rate on the deformation behaviour were shown by the Zener-Hollomon parameter in an exponent-type equation. As a result, a model was developed to predict the high temperature flow behaviour of the Cu-28Zn pre-alloyed powder compact. The results indicated that the strain-dependent constitutive equations are in good conformity with the experimental results.
10.1080-00325899.2017.1357781	-1		The compacting pressure is one of the key parameters which affects sintering phenomena, such as fragmentation, rearrangement and densification. However, the type of alloy also has a similar significance which should be considered. To demonstrate the effect of the mentioned parameters, two types of copper base alloys, i.e. Cu-9Sn-8Pb and Cu-28Zn, were investigated in the present study. Prealloyed powders were compacted at 100 and 400 MPa, respectively, and sintered in the range of 890-970 degrees C for 20 min. In situ images of the samples were taken at various sintering conditions, and the shapes were recorded. For both materials, in case of compaction at lower pressure, the gravity-induced distortion known as 'elephant foot' phenomenon was not observed, and the specimens show shape retention during sintering even at higher temperatures, while samples compacted at 400 MPa showed different responses to the sintering conditions: A-shaped distortion (elephant foot) occurred in the bronze alloy, while in the brass alloy O-shaped distortion was observed.
10.1080-00325899.2017.1377383	-1		In this investigation, an adapted model was developed to predict the dynamic recrystallisation (DRX) flow stress curves of brass Cu-28%Zn, produced via the press-and-sinter route with a nonlinear approximation of the strain hardening rate vs. strain up to the critical stress, using a constitutive equation and Avrami description of DRX. The investigated temperature range was 550-850 degrees C. In this research, according to the microstructure change up to critical point, a separate model was used and after that point a constitutive model considers DRX was presented. This model is used for predicting untested temperatures in order to be utilised in deformation simulation. To evaluate the compound model precision, the mean error was measured. The results demonstrated that the suggested model is in good agreement with experimental results.
10.1080-00325899.2020.1793524	-1		In this paper, a combined processing method of mechanical alloying and infiltration was used to prepare the WCu-xwt-%SiC (x = 0.5, 1, 2, 3) composites. The microstructure, density, electrical conductivity and compressive behaviour of the composites were studied comparatively. First a decreasing and then an increasing particle growth trend was obtained, indicating that a small content of SiC below 1 wt-% was beneficial for particle refinement. Besides this, with the increase of the SiC content, both the density and electrical conductivity decreased gradually. Consistent with the particle-particle contiguity of the highest value of 0.404, the WCu-1 wt-%SiC composite showed the best compressive properties. Further electron backscattering diffraction results revealed that the ultrafine-grained SiC particles, which are distributed homogeneously in the composite with lower Schmid factor values would perturb the dislocation motion to make proliferation of more dislocations, exhibiting unordinary strain-hardening during deformation.
10.1080-00325899.2020.1833139	10	composites; nanoparticles; strength; matrix; high; strengthening; particles; conductivity; composite; electrical; mpa; sintering; ods; grains; mechanical	In this study, a novel W and TiO(2)synergistic strengthened copper matrix nanocomposite was prepared by a powder metallurgy route with a mechano-chemical method and subsequent consolidation. Nano-sized W and TiO(2)particles in the composite powder were fabricated by solid-phase reaction during the mechanical alloying procedure. The average sizes of W and TiO(2)particles were only 51 and 171 nm, far finer than single-phase particle-strengthened composites. It was found that the nanoparticles effectively resisted the grain coarsening in the copper matrix, containing the grains with an average size of 350 nm. The ultimate tensile strength and electrical conductivity of the copper composite are 520 MPa and 74 %IACS, achieve an ideal trade-off between them. The observations suggested that the nanoparticles were highly uniformly dispersed in the copper matrix, and the particle coarsening was restrained as the results of the interaction effects between W and TiO(2)nanoparticles.
10.1080-00325899.2020.1847847	5	materials; thermal; heat; properties; material; welding; sintering; fusion; strength; laser; heat sink; thermal conductivity; mechanical; sink; manufacturing	The difficulty of manufacturing industrial W-Cu alloys by traditional techniques encourages the study of processing by advanced powder metallurgy. From among hot pressing techniques, Rapid Sinter Pressing has been selected since it offers short cycles and versatility. The effect on the properties of W-Cu alloys manufactured by this fabrication method has been studied, in which the processing parameters have been fixed (980 degrees C, 150 MPa, 15 bar/s and 40 s). Different particle sizes of the starting powder materials together with various relative alloy compositions have been employed in order to determine the degree of influence on properties such as hardness, density and thermal conductivity. Through a microstructural characterisation of the samples, the best distribution was related to the use of the intermediate size W particles and fine Cu particles. Concerning the properties, the composition based on 80W-20Cu resulted in the best combination.
10.1080-00325899.2021.1992135	-1		A new oxide dispersion strengthened Cu-0.7wt-%Cr-0.11wt-%Zr material was processed via mechanical alloying (MA) and hot isostatic pressing (HIP). A fine dispersion of yttria particles (Y2O3) was incorporated to the Cu matrix via the addition of yttrium (III) acetate tetrahydrate (C6H9O6Y center dot 4H(2)O) powder (Y3ATH), which decomposed during thermomechanical processing and subsequent thermal annealing. The microstructure after consolidation by HIP revealed the coexistence of zones with a low and high density of precipitates/particles, LDPZ and HDPZ, respectively. The HDPZ were characterized by fine grains with an average size of similar to 300 nm and fine Y-O rich particles (similar to 40 nm) and Cr rich coarse particles (similar to 215 nm), homogenously distributed in the Cu matrix. However, the LDPZ contained coarse grains containing 60 degrees/< 111 > (sigma 3) twins' boundaries.
10.1080-00325899.2023.2179207	-1		Laser powder bed fusion of metals (PBF-LB/M) is advantageous for manufacturing bulk metallic glasses with size and geometrical freedom. However, the oxygen uptake along the production chain can negatively impact the generation of high-quality, amorphous parts. In this context, Cu-Ti-based alloys were gas-atomised and additively manufactured using commercial- (CP) and high-purity (HP) feedstocks. The oxygen absorption in each processing step was tracked and related to the amorphous phase formation and glass-forming ability (GFA) of alloys. Results show an increasing oxygen absorption, considerably influenced by the starting feedstock, especially for CP. In HP material, the most contribution is inherent from the powder oxygen content. Results reveal the lack of influence of the oxygen content in the GFA. TEM analysis of commercial powder and PBF-LB/M sample show uniform and featureless micrographs, displaying the absence of oxygen-induced nucleation. The present contribution enhances the qualification and economic processability of amorphous metals by PBF-LB/M.
10.1080-00325899.2023.2226944	3	sma; shape; shape memory; memory; smas; superelastic; bars; damping; cu-al-mn; mechanical; bending; applications; numerical; sma bars; material	A method to manufacture a porous Cu-Al-Ni shape memory alloy by powder metallurgy using space holders is presented. Two aluminium powders with different particle morphologies were employed to investigate their influence on phase formation, microstructure and mechanical properties. The variation of the relative amount of space holders in the mixture allows to obtain different porosities. Samples prepared with irregular-shaped aluminium powder include both 18R and 2H martensitic phases and exhibit the shape memory effect and pseudoelastic behaviour under uniaxial compression tests. In contrast, the samples made with aluminium flakes present the & alpha; phase accompanying the 18R martensitic phase, and do not exhibit the shape memory effect. Both the aluminium flakes flat shape and the higher proportion of aluminium oxide associated with its larger surface area to volume ratio hindered the interdiffusion of the metals, resulting in an aluminium-depleted martensitic phase surrounded by an aluminium oxide-rich layered structure.
10.1080-01418610108214433	-1		Transmission electron microscopy (TEM) observations of the dislocation substructure developed in high-purity single crystals of Cu deformed at 4.2 K have been carried out in order to relate the detailed defect structures to the mechanical and electrical properties discussed in part I. The results based on weak-beam TEM show that the dislocation substructure contains a very high density of narrow dislocation dipoles of vacancy character. These dipoles become progressively refined in scale as deformation continues. In-situ annealing experiments carried out in the transmission electron microscope allow the stability of these structures against annealing at room temperature and elevated temperatures to be studied. The observations suggest that fine dislocation dipoles can be annealed by processes such as pipe diffusion and that these defects represent the recoverable component of electrical resistivity. For comparison some studies were undertaken in Cu-5 at% Ni single crystals which indicate that the recoverable component of resistivity in this alloy is smaller owing to the influence of the Ni on the pipe diffusion process. In addition, TEM studies indicate the complexity of processes occurring at the twin-parent interfaces produced in Cu deformed at 4.2 K. These interfaces have an important role in debris storage and in processes that can occur after large plastic strains at 4.2 K.
10.1080-01418639708241109	9	magnetic; magnetization; magnetoresistance; temperature; superparamagnetic; annealing; gmr; field; magnetic properties; ferromagnetic; granular; samples; magnetic field; melt-spun; particles	Magnetic correlation effects in nearly superparamagnetic granular Cu100-xCox systems exhibiting giant magnetoresistance (GMR) are studied by analysing the flat-top parabolae obtained when the GMR is plotted as a function of reduced magnetization. The nature of GMR in granular metallic systems is discussed in detail, taking into account the typical time constants involved in the short-time dynamics of magnetic moments in a local magnetic field. An outline of a theory providing the first quantitative explanation of the effect of magnetic correlation on GMR is given. The role of Co content in the sizes and distances of Co particles and in their degree of magnetic correlation are discussed, examining, for studied composition each, the samples characterized by the best GMR values.
10.1080-01694243.2012.701465	-1		The oxidation failure of a copper alloy lead frame with/without a copper plating layer was investigated. The oxidation rate and adhesion strength of oxide films on copper alloy substrates were studied by measuring the thickness and by carrying out peel tests. The adhesion strength of the oxide film was mainly influenced by the composition but not the thickness of the oxide film. The highest adhesion strength was obtained when the oxide film was composed mainly of Cu2O. When the thickness of the copper preplated layer was over 0.165 mu m, the Cu atoms of the preplated copper were available for oxidation. Thus the oxidation process was within the copper preplated layer, and the main product of the oxidation was Cu2O. It was found that the large column grain of the oxide film on the copper alloy with a copper plated layer, favored the diffusion of copper or oxygen atoms that led to the formation of Cu2O, and lead to higher adhesion strength . This indicated that the oxidation resistance of a copper alloy lead frame can be effectively improved by electroplating copper.
10.1080-01694243.2014.903567	-1		In this study, it is shown that the rate of bond degradation due to ageing in hot & humid conditions can be significantly reduced by the use of a Cu-Zn-Co ternary alloy coating, compared to current compounds and normal brass-coated steel cord. To better understand the adhesion mechanism, X-ray photoelectron spectroscopy is used to investigate the adhesion interface upon hot and humid ageing. In addition, the effect of removal of cobalt salts from compound on static and dynamic rubber compound properties is studied: it is found that this leads to improved heat ageing resistance, slower crack growth rate and less hysteresis. Hence, the new Cu-Zn-Co ternary alloy coating for steel cord allows cobalt salts to be removed from tires, which makes tires more durable and eco-friendly.
10.1080-02670836.2015.1114696	16	wear; composite; composites; powders; milling; particles; powder; wt; sliding; friction; hardness; matrix; mechanical; surface; properties	Two different methods are used to prepare Cu-20 vol-% Al2O3 nanocomposite powders via high-energy planetary fast milling. In the solid solution method, CuO powder was added to the Cu-Al solid solution powder, and the composite was fabricated by milling after 100 h . In the direct mixing method, Cu and Al2O3 powders were mechanically milled via high-energy planetary fast milling for 100 h . The transition electron micrographs (dark and white fields) revealed the presence of Al2O3 nanoparticles in crystalline Cu matrices for both methods. However, the density and bending strength of the nanocomposites produced via the solid solution method were higher than those of the samples produced via the direct mixing method.
10.1080-02670836.2016.1258154	-1		Cu-La alloys with various additions of La were prepared in a vacuum electric furnace. The effects of La additions on the absorptivity and purification of La in as-cast pure copper were investigated. The results show that the absorptivity of La increases with increasing additions. However, this is as a result of reactions with impurity elements in the copper and further oxidation in the atmosphere. Meanwhile, the addition of La further reduces the contents of impurity elements such as Si, Pb and S, and purifies liquid copper more effectively, which can help to improve the mechanical properties of as-cast pure copper. However, excessive rare earth element additions can lead to decreases in elongation due to the excessive formation of intermetallic compounds.
10.1080-02670836.2017.1279856	-1		By applying high-density electric current pulses (ECP) on the Cu-Zn alloy, the high-temperature precipitated phase is explored and the related mechanical properties are investigated. Results show that the nucleation rate of the high-temperature beta precipitation can be greatly accelerated due to the ECP treatment. Especially, an obvious orientation relationship can be detected between the matrix a phase and the product beta precipitation by increasing the electric current density. In addition, for the samples with a dense distribution of refined beta precipitation, a slight decrease in the tensile strength and a great increase in the elongation-to-failure can be observed.
10.1080-02670836.2017.1366711	17	wear; composites; coating; friction; composite; coatings; surface; tribological; properties; wear resistance; resistance; powder; sliding; matrix; wear rate	An ultrafine (similar to 100 nm) W particle-reinforced Cu matrix composite was fabricated by spark plasma sintering. The tribological properties of the fabricated W/Cu composite were tested by pin-on-disc sliding experiments and compared with those of brass alloy. The wear rate of the carbon brush when sliding against the W/Cu composite (0.102mm(3) s(-1)) was much lower than that with brass (4.83mm(3) s(-1)). Simultaneously, the W/Cu composite possessed higher conductivities and greater surface hardness than brass. The surface roughness of the W/Cu composite was found to play a critical role in improving the robustness of the tribofilm and reducing the volume loss of the carbon brush . The W/Cu composite has promising engineering applications for the long-term wear protection of self-lubricating materials.
10.1080-02670836.2017.1390645	15	aging; strength; conductivity; electrical conductivity; electrical; mpa; treatment; strengthening; degrees; cu-; cold; precipitation; tensile strength; tensile; iacs	A copper alloy of Cu-1.9 wt-% Ti-0.7 wt-% B was fabricated by vacuum induction melting and casting followed by cold working and annealing. Four strengthening methods has been involved during the preparation of the alloy, and the combined action of these methods results in the alloy with the tensile strength of 530 +/- 24 MPa and the electrical conductivity (EC) of 48.0 +/- 2.1% International Annealed Copper Standard. The specific contribution (or deterioration) of different strengthening methods to hardness and EC was quantitatively evaluated. With regard to combined properties of Cu-Ti-B alloys, age hardening and forming TiB2 particles are two effective methods to improve hardness and to maintain EC at a relatively high level simultaneously, but solid solution strengthening and work hardening are two inferior strengthening methods.
10.1080-02670836.2018.1459094	-1		The microstructure and mechanical properties of a Cu-Cr-Ag alloy at the different processing stages were investigated using hardness measurements, scanning electron microscopy, and transmission electron microscopy. The combined effects of dislocation strengthening and precipitation strengthening were shown to remarkably enhance the hardness of the alloy. Coherent Cr-rich precipitates with a face-centred cubic structure, formed during aging, were shown to be the main source of age strengthening, and the introduction of pre-deformation led to acceleration of their precipitation. Nevertheless, recovery occurring during aging caused significant softening in the cold-drawn samples. Analysis of the microstructural evolution during cold drawing and aging was used as an effective tool to optimise the thermomechanical process and improve the mechanical properties.
10.1080-02670836.2018.1462299	-1		The influence of hafnium element's incorporation on a Cu-xHf-13.0Al-4.0Ni (wt-%) (x = 0.5, 1.0 and 2.0) high-temperature shape memory alloy was investigated systematically. The results show that the matrix of Cu-xHf-13.0Al-4.0Ni (x = 0.5, 1.0 and 2.0) alloys is 18R martensite, and an orthorhombic-structured Cu8Hf3 phase is formed and distributed at the grain boundaries. The grain size is significantly reduced with increasing Hf content. The mechanical properties of Cu-xHf-13.0Al-4.0Ni (x = 0.5, 1.0 and 2.0) alloys are improved by Hf doping due to the combination of refinement strengthening, solid solution strengthening and second phase strengthening. After heating under pre-strain of 10%, the shape memory effect of the Cu-1.0Hf-13.0Al-4.0Ni alloy reaches 5.6%, which is obviously higher than that of the Cu-13.0Al-4.0Ni alloy.
10.1080-02670836.2018.1495414	-1		We studied the effect of the regimes of ultrasonic action on the structural transformation during free upsetting with 50% reduction of the copper alloy Cu-0.5Cr. In the process of deformation, the samples were subjected to intermittent and continuous ultrasonic actions. It can be noted that the application of ultrasonic vibrations in the process of deformation leads in both cases to a reduction in yield strength . Under a continuous ultrasonic action with a power of 640 W, the most developed structure is formed, with a fraction of high-angle boundaries equal to 32.4%, with the lowest values of coherent scattering regions, density of dislocations and microdistortions, while the decline in yield strength of the material under deformation is 40 MPa. This paper is part of a Thematic Issue on Copper and its Alloys.
10.1080-02670836.2018.1498433	-1		Cu-Ni-Si alloys exhibit a good combination of strength and electrical conductivity and may be a potential candidate for utilisation in electrotechnical applications. In this work, the mechanical behaviour and its relation to the microstructure of a Cu-Ni-Si alloy, subjected to different solution heat treatment cycles, were investigated. Tensile, bend and hardness testing, in addition to Optical and Scanning Electron Microscopy, were employed, as the main analytical techniques, in the context of the present investigation. This paper is part of a Thematic Issue on Copper and its Alloys.
10.1080-02670836.2018.1542554	15	aging; strength; conductivity; electrical conductivity; electrical; mpa; treatment; strengthening; degrees; cu-; cold; precipitation; tensile strength; tensile; iacs	Mo could be dissolved into Cu to increase its high-temperature stability via a Ni intermediate. The microstructure evolution and strengthening mechanism of Cu-x[Ni3Mo] (x = 1, 2, 3, 4, 5, 7, 9, 12) alloys were investigated. The results show that composition significantly affects strengthening mechanisms of the alloys. For x = 1 and 2, The strengthening mechanisms of the alloys are mainly precipitation strengthening derived from Ni2Mo and Ni4Mo nanophases, both of which coexist and coherently grow on the face-centered cubic matrix. For x = 3-5, the nanophases gradually decrease and spinodal decomposition structure increases, which transforms the strengthening mechanism to spinodal decomposition strengthening. For x = 7-12, spinodal decomposition structure and precipitates reduce significantly, the solution strengthening dominates namely.
10.1080-02670836.2018.1545290	-1		7N01 Al alloy is used extensively in high-speed train production. The mechanical properties of Al-Zn-Mg-Cu alloys are known to be closely related to the characteristics of their precipitates, which are greatly affected by the heat-treatment temperature. Herein, differential scanning calorimetry (DSC) and transmission electron microscopy (TEM) were used to investigate the precipitation kinetics and structure of eta precipitates in 7N01 alloy. The solution temperature range of precipitation and the activation energy of eta were determined using DSC analysis, and the chemical composition and crystal structure of the eta precipitates were characterised using TEM. A relationship between the solution temperature and crystal structure was established, providing insight into the selection of the heat-treatment temperature for 7N01 alloy.
10.1080-02670836.2019.1576374	-1		The microstructure and properties of a Cu-Ni-Co-Si alloy were investigated through high-resolution transmission electron microscopy and three-dimensional atom probe analysis after aging at 500 degrees C for various times. Characterisation along different diffraction directions showed that precipitate morphology was disk shaped. The concentration profiles for Ni, Co, and Si were flattened in the precipitate interiors at levels of approximately 30, 35, and 35 at.-%, respectively. The co-segregation of Co was more significant than that of Ni and Si owing to the extremely low solubility in the matrix at room temperature. Theoretical calculations excellently agreed with the experimental data, which demonstrated that solid solution scattering and the Orowan bypass mechanism were the key reinforcement mechanisms for electrical and mechanical properties, respectively.
10.1080-02670836.2019.1578918	-1		Nano-sized iron-rich precipitates reinforced copper alloys achieve excellent mechanical properties. Capture mechanism of iron-rich precipitates into copper grains during solidification was described but needs further validation. Here, Cu-1.5Fe-0.5Co (wt-%) alloy is fabricated by gravity casting. Iron-rich precipitates in nano and submicron scale (mostly < 100 nm) are well dispersed in copper grain interior. Traditional pushing/engulfment transition (PET) models are used to interpret the capture process of iron-rich precipitates during copper solidification, but all fail to match the experimental results. The precipitates-interaction capture mechanism is most reasonable for describing the capture process.
10.1080-02670836.2019.1596584	-1		Ti50Cu50 (at.-%) alloy has been produced from elemental Ti and Cu powders by high-energy ball milling in a planetary ball mill. Structural evolution of the alloy during milling and after subsequent heat treatment have been studied. It has been stated that high-energy ball milling of the investigated powder produces two nanocrystalline solid solutions: Cu(Ti) and Ti(Cu), both characterised by the fcc (Fm-3 m) structure. The transition of Ti structure from hcp (P63/mmc) to fcc (Fm-3 m) is observed during milling. Heat treatment of the milled powder leads to recrystallisation of Cu(Ti) and Ti(Cu) solid solutions.
10.1080-02670836.2019.1630089	16	wear; composite; composites; powders; milling; particles; powder; wt; sliding; friction; hardness; matrix; mechanical; surface; properties	Lead-free alloys have attracted great attentions recently due to the toxic nature of lead for the human body. In this study, low amounts of Mg and Sb were added to the Cu65-Zn35 brass and microstructure, mechanical properties and machinability of samples were compared to Cu65-Zn35 brass. Both Mg and Sb led to the promotion of beta ' phase as well as the formation of new ternary copper rich intermetallic particles. It was found that these particles had a significant role in the reduction of the ultimate tensile strength, toughness, work hardening and elongation while increasing the hardness of samples. Results of machinability evaluation of samples showed that the cutting forces were decreased significantly and morphology of chips were improved compared to Cu65-Zn35 brass sample.
10.1080-02670836.2019.1636179	15	aging; strength; conductivity; electrical conductivity; electrical; mpa; treatment; strengthening; degrees; cu-; cold; precipitation; tensile strength; tensile; iacs	Grain boundary migration in different casting processes directly affects the grain size of the ingot, which affects the mechanical properties of the alloy. In this study, Cu-Cr-Zr-Ti rods are manufactured using upward continuous casting and casting-extrusion processes followed by drawing. It is found that the strength of the upward continuous casting rods is 621 MPa, greater than that of the casting-extrusion rods 571 MPa, which is a result of different microstructure evolution during solution treatment. Calculations of the driving force and resistance of grain boundary migration were performed to explain the observations.
10.1080-02670836.2019.1651474	15	aging; strength; conductivity; electrical conductivity; electrical; mpa; treatment; strengthening; degrees; cu-; cold; precipitation; tensile strength; tensile; iacs	The microstructure, mechanical properties, and electrical conductivity (EC) of Cu-4Ti-Cr-Fe alloy aged at 773 K in vacuum are studied in this work. The results show that the multiple trace alloying elements have little effect on the microstructure evolution during the aging treatment at 773 K. However, with prolonged aging, the hardness, yield strength, and tensile strength first increase, then decrease. The Cu-4Ti-Cr-Fe alloys show superior hardness and strength performance than other alloys. In both the solid-solution treated and aged cases, the EC decreases if multiple trace alloying elements are added to the Cu-4wt-%Ti alloys, which indicates the CuTi intermetallic compound may have a large negative influence on the EC of copper alloy.
10.1080-02670836.2019.1658439	11	glass; bulk; metallic; bulk metallic; gfa; bmg; glassy; metallic glass; ability; bulk metallic glass; amorphous; addition; crystallization; mm; glass-forming	The effects of Nb on the microstructures and mechanical properties of large-sized (Cu0.47Zr0.47Al0.06)(99-x)Ni1Nbx (x = 0, 0.5, 1, 2 at.-%) bulk metallic glass composites were investigated. It is verified that the liquidus temperature (T-l) of the Nb-added alloys decreases to cause the increase of glass-forming ability (GFA). The addition of Nb adjusts the distribution and the volume fraction of B2-CuZr phase in the Cu-Zr-Al-Ni large-sized composites by changing the GFA of the alloys. The mechanical properties of the composites strongly depend on the volume fraction and distribution of B2-CuZr phase in the glassy matrix. The alloy with 0.5 at.-% Nb addition exhibits the high mechanical properties, which should be attributed to the uniform distribution and the proper volume fraction of B2-CuZr phase in the glassy matrix.
10.1080-02670836.2019.1684035	15	aging; strength; conductivity; electrical conductivity; electrical; mpa; treatment; strengthening; degrees; cu-; cold; precipitation; tensile strength; tensile; iacs	The effect of heat treatment on the mechanical properties and microstructures of Cu-6.9Ni-2.97Al-0.99Fe-1.06Mn alloys was investigated. The results show that the microstructure of the as-cast alloy mainly consists of an alpha-copper matrix and gamma-phase Ni3Al particles. The microstructure of the alloy after solution treatment at 950 degrees C for 2 h is a single-phase alpha-copper supersaturated solid solution and the second-phase strengthening disappears. After ageing treatment at 550 degrees C for 6 h, the gamma-phase particles are fully precipitated, and the mechanical properties of the alloy are significantly improved. The tensile strength is increased from 305 to 588 MPa. Quasi-cleavage fracture with shallow dimples appeared in the Cu-6.9Ni-2.97Al-0.99Fe-1.06Mn alloy aged at 550 degrees C for 6 h .
10.1080-02670836.2020.1726600	-1		The microstructural evolution of an overaged Cu-4wt-%Ti alloy associated with surface mechanical attrition treatment (SMAT) has been studied by X-ray diffraction, scanning electron microscope and transmission electron microscopy. The results show that beta-Cu4Ti precipitates in the topmost surface layer were dissolved after SMAT, and Cu solid solution phase with a fine grain size of approximately 25 nm was observed. Dislocation activities were the main deformation mechanism of lamellar structure in the overaged Cu-4wt-%Ti alloy. The twinning in lamellar Cu phase was inhibited by the beta-Cu4Ti precipitates.
10.1080-02670836.2020.1738070	-1		Cu-Ni/B4C diffusion couples were prepared by pressure-assisted sintering at different temperatures for different lengths of time under vacuum condition, and then phase composition and reaction kinetics of the products in the Cu-Ni alloy were investigated systematically. Results show that there is a reaction that occur between the Cu-Ni alloy and B4C, whose reaction products are Ni2B particles inside the Cu-Ni alloy along with a mixture of Ni2B and amorphous C at the interface between them. The diffusion of B into Cu-Ni alloys, important to the preparation of (Ni2B + C)/Cu composites, is interface-controlled and the thickness of the reaction layer containing Ni2B particles inside the Cu-Ni alloys can be expressed as delta = 3.45 x 10(7) exp(-(137.32 x 10(3))/RT)t(0.9).
10.1080-02670836.2020.1753153	-1		Alloying of Fe, Co was reported to tailor microstructure of copper alloys into a nanoprecipitate-fine grain (NPFG) structure, i.e. nano-sized iron-rich precipitates dispersed inside refined grains. Here, we investigate the solute effect of Sn, Zn on NPFG structure in as-cast copper samples. Mechanisms are proposed to account for the solute effect on precipitate and grain features. Solutes restrict coarsening but facilitate undesirable morphology transition from spherical to angular of iron-rich precipitates. Meantime, solutes allow more precipitates to be active in the nucleation of copper and consequently induce finer grains. Minor Sn is added to optimise NPFG structure and leads to an excellent strength-ductility combination in Cu-1.5Fe-0.1Sn (wt-%) alloy. This work provides a solute-alloying strategy to achieve desired mechanical properties in metals.
10.1080-02670836.2020.1753156	-1		Nanoporous copper (NPC) with a controllable ligament width was prepared by chemically dealloying Cu45Al45Ti10 amorphous ribbons in dilute HCl solution. X-ray diffraction and scanning electron microscopy analysis confirmed the 3D, bicontinuous, nanoporous structure constituting fcc-Cu ligaments of 39-79 nm thickness. The coarsening of NPC ligaments increased significantly with an increase of HCl concentration, reaction temperature or time. The surface diffusivity and activation energy of NPC were also calculated. Finally, the catalytic activity of NPC was validated with the ultrasound and H2O2-assisted degradation of methyl orange (MO), where 99% MO was degraded within 15 min.
10.1080-02670836.2020.1759275	-1		The recrystallization behaviour during annealing of cold-rolled Cu-5Fe-2Sn alloy was clarified in this paper. The effects of annealing temperature and time on the microstructure and properties of the Cu-5Fe-2Sn alloy were investigated. The equations of electrical conductivity and recrystallization kinetics during annealing were obtained with Martition's rule and Avrami empirical formula. The variations of recrystallization volume fraction and the growth of recrystallization grain for Cu-5Fe-2Sn alloy after 40% cold rolling were discussed. The calculated conductivity and volume fraction of recrystallization have a good match with experimental results. The variations of the properties of annealed Cu-5Fe-2Sn alloy are attributed to the growth rate of recrystallization phase and the size of recrystallization grains.
10.1080-02670836.2021.1913548	-1		The stress relaxation behaviour of Cu-0.23Cr-0.08Ag alloy was studied at different deformations (10%, 20%, 30%). The high percentage of low Sigma CSL (Coincidence Site Lattice) grain boundary could improve the stress relaxation resistance of the alloy. There are two main factors affecting the stress relaxation resistance: one is the pinning effect of Cr to movable dislocations; the other is the obstacle of twins to the movement of movable dislocations.
10.1080-02670836.2021.1944487	15	aging; strength; conductivity; electrical conductivity; electrical; mpa; treatment; strengthening; degrees; cu-; cold; precipitation; tensile strength; tensile; iacs	The Cu-Cr-Ti alloys with different Ti contents were prepared by vacuum induction melting, solid solution, cold deformation, and ageing treatment. The microstructures, mechanical, and electrical properties of Cu-Cr-Ti alloys were investigated under different Ti contents. The results indicate that the increase of Ti content can improve the mechanical properties of Cu-Cr-Ti alloys, whereas its conductivity decreases significantly. After cold rolling by 80% and ageing at 500 degrees C for 60 min, the Cu-0.3Cr-0.05Ti alloy with the hardness, electrical conductivity, and tensile strength are 162.6 HV, 82.2% IACS, and 510 MPa, respectively. The strengthening mechanism of the studied alloys is mainly attributed to the Orowan precipitation and dislocation strengthening. The addition of Ti in the ageing process can retard the growth and coarsen Cr precipitates.
10.1080-02670836.2021.1996127	0	solidification; phase; magnetic; magnetic field; undercooling; field; liquid; separation; peritectic; immiscible; cu-; dendrite; phase separation; microstructure; primary	Novel Cu-24Pb-xAl alloys with dispersed and rodlike Pb-rich secondary phases (PSPs) were designed and prepared with the guidance of CALPHAD. Through primary binary-phase diagram analysis and thermodynamic calculation, Al was proven to be a suitable alloying element in Cu-Pb system to promote the formation of dispersed and rodlike PSPs during solidification by introducing a (L-1 +L- (2 )+( )alpha-Cu) phase region in Cu-Pb-xAl systems. The Cu-24Pb-xAl (wt-%, x = 0, 2, 4) alloys were then prepared in order to verify the reliability of the alloy design strategy. Cu-24Pb-2Al alloy with rodlike PSPs was successfully designed and prepared. A novel strategy to design Cu-Pb-(X) immiscible alloy with optimised microstructure is thus proposed in this work which can help establish a design criterion for other immiscible alloys.
10.1080-02670836.2021.2015838	-1		In situ spherical TiCp-reinforced copper matrix composites were prepared via hot-pressing sintering assisted with copper plating. Brinell hardness and electrical conductivity of composites with various contents were investigated, room temperature compression properties and fractography of optimal TiCp/Cu composites and sintered pure copper were analysed. It was found that with the increase of TiCp content, Brinell hardness of composites was increased, while electrical conductivity decreased. When TiCp content was 1.0 wt-%, the Brinell hardness increased significantly and the conductivity was maintained at a high level. Compared with sintered pure copper, the yield strength and ultimate compressive strength of the composites were improved, while the fracture strain was reduced.
10.1080-02670836.2021.2023837	-1		Fine-grained 7034 aluminium alloys were soldered with Zn-5Al filler metals, using liquid Ga as protective coatings to remove oxide films of the base and filler metals and prevent secondary oxidation. Holding times and coating modes were adjusted by experiments. Applying the Ga coating on both the base and filler metals caused the Ga enrichment in the alpha-Al particles and the formation of Mg2Ga5 intermetallic compound at the bonding interface, deteriorating joint mechanical performance. Ga enrichment was prevented by applying the coating on the filler metal alone, which avoided the early contact of Ga with Al substrate and reduced the mass of Ga in the joint. The tensile strength increased significantly to 159 similar to 185 MPa with a sufficient holding time.
10.1080-02670836.2021.2024044	-1		The detailed characteristic of the tribo-layer in an age-hardening Cu-15Ni-8Sn alloy was studied with advanced analysis techniques. A comprehensive picture of the tribo-layer was drawn from nanoscale to macroscale. The characterisation was done for the oxide layer (OL) that is easy to scaling off during the preparation of metallographic samples, showing a homogeneous mixture of oxide and nanocrystalline particles with a thickness of several micrometers. The mechanically mixed layer (MML) is a multi-layer structure. In addition, the spinodal structure and ordered intermetallic precipitates existing in the matrix were gradually transformed or disappeared in OL and MML. Furthermore, there is a nanocrystalline transformation on the top of plastically deformed layer (PDL), where thin twin-matrix lamellar structure and equiaxed nanocrystallines were formed.
10.1080-02670836.2022.2025559	6	grain; deformation; strain; strength; dislocation; cu-; tensile; size; ecap; grain size; sfe; ductility; hardening; high; stress	Copper-zinc alloys with different zinc contents contain different stacking fault energies (SFE). The influence of SFE on the deformation mechanism during surface mechanical attrition treatment was studied in this work. Research results indicate that the deformation mechanism directly correlated with the SFE in Cu-Zn alloys. Deformation twinning plays a paramount role during original deformation in Cu-20Zn (19 mJ/m(2)). However, for Cu-2Zn alloy with low-medium SFE (38 mJ/m(2)), the deformation mechanism is dominated by the dislocation slipping. Microbands are the predominant microstructural features in large strain and high strain rate regions for both Cu-Zn alloys in the present study. They are likely to be formed by the splitting of the high-density dislocation walls.
10.1080-02670836.2022.2043028	-1		Mn-Cu-based damping alloy prepared by directional solidification is very promising for vibration and noise control. Aging treatment with and without application of magnetic field on the microstructure and damping performance of directionally solidified Mn-Cu alloy was studied by means of X-ray diffraction, differential scanning calorimetry, dynamic thermal mechanical analysis and scanning electron microscope. It is found that aging treatment makes the orientation shift from (200) to (111), and aging treatment under magnetic field helps Mn-Cu alloy keep high damping in the wide temperature range. The polymorphic microstructure characterised by fine twin bands with low-angle misorientation boundaries leads to a substantial increase of twin boundary internal friction up to several times higher than that of polycrystalline state.
10.1080-02670836.2022.2062638	-1		The gravity die casting method was used to produce functional Cu-Cr-Zr alloys with various compositions. The functional electrical, mechanical, and wear properties of Cu-Cr-Zr alloys were studied at different aging times at 500 degrees C. The optimum aging time that results in the best combination of hardness and functional electrical properties changes with the chemical composition of the alloys; the alloys with higher Zr content require a longer time to attain peak hardness. Complicated wear mechanisms are active in the Cu-Cr-Zr alloys. The alloys with the highest Zr and Cr contents exhibit the highest hardness and tensile strength with low wear resistance. The best Cr content is found to be just below the solubility limit at the solutionizing temperature.
10.1080-02670836.2022.2062651	-1		Liquid nitrogen temperature (LNT) rolling at a high strain rate was applied to in-situ TiB2/Cu composites fabricated by powder metallurgy. An artificially controlled heterogeneous distribution of TiB2 particles in a Cu matrix leads to bimodal microstructures in the LNT-rolled composites, i.e. reinforcement-rich regions are constituted by in-situ formed TiB2 particles and nano-Cu grains (about 25 nm), while reinforcement-poor regions are mainly composed of heavily deformed ultrafine Cu grains (about 0.5 mu m). Compared with TiB2/Cu composites processed by normal rolling, LNT-rolled TiB2/Cu composites with heterogeneous microstructures exhibit good overall performance with high ultimate tensile strength (594 MPa), high elongation (6.3%), high electrical conductivity (82.6% International Annealed Copper Standard) and improved thermal stability, which is favourable for electrical and electronic device applications.
10.1080-02670836.2022.2110289	-1		Tailoring the compositions of the functional Cu-Cr-Zr-La/Ce alloys involve producing alloys with dilute (0.05%), low (0.16-0.2%), medium (0.41-0.44%), and high (0.66-0.91%) Cr content at dilute (0.06%), medium (0.5%), and high (0.98%) Zr content with (0.23-0.4%) La or (0.03-0.12%) Ce. The effect of these compositional differences on the microstructure, hardness, and electrical properties was studied for different aging times (0, 1, and 1.5 h). The best combination of hardness and electrical properties was achieved after 1.5 h of aging for all studied alloys. The effect of the chemical composition on tensile properties and wear resistance was studied after 1.5 h of aging. Unlike Zr, high Cr content has a negative influence on the tensile strength and wear resistance.
10.1080-02670836.2023.2165653	6	grain; deformation; strain; strength; dislocation; cu-; tensile; size; ecap; grain size; sfe; ductility; hardening; high; stress	A bulk Cu-1 wt%Al2O3 composite was synthesised to 97-99% theoretical density by mechanical alloying and spark plasma sintering to get varying grain sizes in the range 70 nm-2 mu m. Tensile tests were done at room temperature, and the substructure evolution was examined as a function of the grain size and strain. The flow property revealed bilinear Hall-Petch relationship with a transition at 0.55 mu m grain size. The stress-strain curves were found to follow the Hollomon-type relationship exhibiting an increase in strength coefficient and a decrease in strain hardening exponent with decreasing grain size. The variations in flow stress with grain size and strain delineate equivalent effects. The inter-dependence between the grain size and strain is explained by the substructure evolution and its contribution to the partitioning of work hardening between the grain interior and grain boundaries.
10.1080-02670836.2023.2170742	8	hot; deformation; strain; strain rate; dynamic; hot deformation; recrystallization; dynamic recrystallization; flow; rate; flow stress; compression; constitutive; degrees; stress	The hot deformation behaviour and microstructure evolution of the Cu-6.5Fe-0.3Mg alloy were explored. The optimum hot working temperature of the alloy was 950? and the strain rate was 10 s(-1). The alloy underwent dynamic recovery (DRV) and dynamic recrystallisation (DRX) behaviour during hot compression. The density of the Fe phase particles increased significantly, and they were all aligned along the vertical compression direction. The alpha-Fe phase transformed to gamma-Fe phase at 950?. A large amount of alpha-Fe and gamma-Fe phases effectively inhibited the DRX behaviour of the Cu-6.5Fe-0.3Mg alloy and significantly improved its thermal stability. The research on the hot deformation behaviour of the Cu-6.5Fe-X alloys had a theoretical guiding role in determining its hot working process.
10.1080-02670836.2023.2186050	15	aging; strength; conductivity; electrical conductivity; electrical; mpa; treatment; strengthening; degrees; cu-; cold; precipitation; tensile strength; tensile; iacs	Many attempts were conducted to improve Cu-Cr alloys' softening temperature, strength, and electrical conductivity. After homogenised treatment at 900 degrees C for 4 h, hot rolled by 80% at 900 degrees C, solid solution treated at 940 degrees C for 2 h, cold rolled by 50%, and aged at 450 degrees C for 1 h, cold rolled by 50%, and aged at 450 degrees C for 0.5 h, the tensile strength, yield strength, microhardness, and electrical conductivity of the fabricated Cu-2Cr-1Zn alloy were 616.7, 540.1 MPa, 176.7 HV, and 71.5% IACS, respectively, with a softening temperature of 530 degrees C. Orowan precipitation strengthening was the primary strengthening mechanism. These findings bring an effective way to improve the strength and softening temperature with a small loss of electrical conductivity.
10.1080-02670836.2023.2195756	15	aging; strength; conductivity; electrical conductivity; electrical; mpa; treatment; strengthening; degrees; cu-; cold; precipitation; tensile strength; tensile; iacs	The Cu-5Fe-xSn alloy was prepared, and the effect of Sn on Fe phase distribution, precipitation kinetics, and properties of the Cu-5Fe alloy were investigated. The tensile strength and conductivity of Cu-5Fe-0.15Sn after aging at 400 degrees C were 712 MPa and 66.6% IACS, respectively. Compared to the Cu-5Fe alloy, the tensile strength increased by about 190 MPa, while the conductivity decreased by only 1.4% IACS. Sn optimises Fe distribution and inhibits dendritic segregation. After drawing, the Fe phase is transformed into Fe fibre. Sn enhances the synergistic deformation ability of Cu/Fe, resulting in better continuity and density of Fe fibres. The precipitation activation energies of Fe in Cu-5Fe and Cu-5Fe-0.15Sn alloys were 95.9 and 84.9 kJ/mol, respectively.
10.1080-02670836.2023.2230004	-1		The effect of interaction between Ce and P on the microstructure and properties of copper has been rarely reported. In this study, it was investigated by utilising the OM, EPMA, SEM and TEM techniques, combined with conductivity and tensile tests. The results indicated that the grain size and conductivity of as-cast copper could be significantly influenced by the interaction. More importantly, the plasticity of as-cast copper did not seriously damage by the interaction, and the elongation of as-cast 3# (Cu-0.016P-0.075Ce) was still up to 39.3%. This is due to a strong binding force of the coherent interface between CeP and copper.
10.1080-02670836.2023.2246773	-1		In this paper, Cu-6.2Fe-xIn (x = 0, 0.2, 0.4) alloy was prepared by melting casting and mechanical heat treatment. The Fe phase morphology of Cu-6.2Fe-xIn alloy was observed by SEM, EBSD and TEM. The results show that the addition of In element refines the primary Fe phase and optimises its distribution. After large plastic deformation, the Fe phase was fibrillated and the addition of In refines the Fe fibre and increases its density. The strength of Cu-6.2Fe-0.4In alloy with strain of 7 were 901 MPa, which was 201 MPa higher than that of Cu-6.2Fe alloy. The refining effect of In on the primary Fe phase was the main reason for the significant improvement of the strength of Cu-Fe-In alloy.
10.1080-02670844.2016.1258165	-1		This study evaluated the effects of shot peening (SP) for modifying the fatigue performance of ultrafine-grained CuNi3Si1Mg. Fatigue damage is possibly caused when electromechanical connectors are subjected to cyclic loading or high numbers of repeated plugging. The fatigue performance of the precipitation-hardened ultrafine-grained CuNi3Si1Mg was significantly enhanced from 325 MPa in the electropolished condition to 400 MPa after SP at an Almen intensity of 0.25 mmA. In the precipitation-hardened ultrafine-grained CuNi3Si1Mg, SP induced a high degree of work hardening and maximum compressive residual stress values on the surface layers, which resulted in a better fatigue performance than the electropolished counterpart. After SP, the dissolution of precipitates in the surface layers also improved fatigue performance by reduction in the negative effect of the surface precipitates.
10.1080-02670844.2020.1748338	-1		Nanocrystalline (NC) Cu-Ta thin films were successfully fabricated by unbalanced magnetron sputtering on crystal silicon and glass substrates. Thin films doped with different Ta contents were prepared by altering the sputtering current of the Ta target. The micromorphology, microstructure, mechanical properties, electrical properties, and thermal stability of the films were investigated. The results on the microstructure of the as-deposited films demonstrated that Ta forms an FCC Cu (Ta) metastable supersaturated substitutional solid solution in Cu. In addition, with the increase of Ta content, the NC Cu-Ta films tended to be amorphous. Furthermore, the grain size of the post-annealed Cu-Ta films increased slightly due to recrystallization and in the metastable solid solution, Ta was exsolved and precipitated from the Cu matrix. The lowest resistivity (3.165 x 10(-7) omega center dot m(-1)) and the highest elastic modulus (125.2 GPa) were obtained with a Ta target current of 0.5 A.
10.1080-02670844.2020.1766866	-1		NiCrAlY/Al2O3-20 wt-%TiO2 gradient coating on Cu-Be substrate was fabricated by atmospheric plasma spraying method. Effect of the phase composition and the microstructure of gradient coating on thermal shock behaviours were investigated by using the X-ray diffraction, scanning electron microscopy and energy dispersive spectrometry. The gradient coating shows a typical lamellar structure with a uniform thickness and good interface. The microhardness of gradient coating was 875 HV compared to the substrate of 199 HV. The thermal shock failure of gradient coating took place after 467 and 37 cycles at 400 and 600 degrees C, respectively. The spallation boundaries of gradient coating with a step structure could be divided into three regions: coating spallation region (I), oxidation region (II) and coating region (III). The mechanism of thermal shock failure was discussed.
10.1080-02670844.2020.1815492	-1		Nanocrystalline-strengthened surface layer significantly improves the surface hardness and wear resistance of Cu or Cu alloys and avoids the reduction of conductivity. However, the poor thermal stability limits its industrial application. Herein, a series of Cu-Ni-Al films were prepared by radio frequency magnetron sputtering, which shows gamma (similar to 20 nm) + gamma ' GREEK TONOS phase (similar to 10 nm) dual nanostructure. Compared with pure Cu film, gamma ' phase precipitation-strengthened films possess higher hardness, outstanding wear resistance and a certain electrical conductivity. The strengthening mechanisms have been discussed in detail. After annealing at 450 degrees C/20 h, the hardness of Cu-Ni-Al films decreases slightly, but their wear resistance remains essentially unchanged, exhibiting superior thermal stability, the main reason of which is that the growth of nanocrystalline Cu can be retarded through the precipitation of gamma ' phases.
10.1080-02670844.2023.2253392	-1		Low-Be copper alloys exhibit high thermal and electrical conductivities but weak strength, hardness, wear and corrosion resistances, which limit their practical applications severely. To overcome these defects, we herein systematically investigate the effects of ultrasonic surface modification on the microstructures and properties of Cu-0.2Be-1.0Co alloy. It is found that the gradient microstructures characterized by pile-ups and dents, fine grains, dense dislocations and compressive residual stresses are generated in the 171 & mu;m thickness surface layer of the Cu-0.2Be-1.0Co alloy by ultrasonic surface modification. As a result, the surface hardness obtains a 162% enhancement, the wear rate drops from 5.03 x 10-4 to 3.46 x 10-4 mm3 & BULL;N-1 & BULL;m-1, and the electrochemical corrosion current density decreases from 3.24 to 1.92 & mu;A/cm2. These results indicate that the comprehensive properties of Cu-0.2Be-1.0Co alloy can be simultaneously improved by utilizing ultrasonic surface modification.
10.1080-02726351.2018.1526834	16	wear; composite; composites; powders; milling; particles; powder; wt; sliding; friction; hardness; matrix; mechanical; surface; properties	Copper alloys and composites find a variety of applications where wear and corrosion resistance are of paramount importance. An attempt has been made to study the behavior of copper alumina composites made through powder metallurgy. Microcrystalline Alumina (Al2O3) and Copper (Cu) powders were synthesized by high energy planetary ball milling to reduce their particle size to nano scale. In the present work, corrosion and wear behavior of copper MMC reinforced with different weight percentages (5, 10, 15%) of Alumina were examined and the results are presented. Powders were characterized by X-ray diffraction (XRD) to obtain the particle size of the composite powders and scanning electron microscopy (SEM) was also used to know the dominant process during each cycle of milling. Green compacts were obtained by compressing the powders into solid by placing them in a rectangular die using a universal testing machine (UTM), sintered in electric furnace and cooled. Wear and corrosion properties of the compacts were studied using Pin-on-Disc apparatus and Standard corrosion test using linear potentiodynamic polarization tester with 3.5% NaCl as per ASTM G99 standards. Best wear and corrosion values were obtained at 15% wt. % of alumina and 10% wt. % of alumina respectively.
10.1080-08927010802578932	2	corrosion; surface; film; electrochemical; films; spectroscopy; layer; current; solution; potential; resistance; composition; x-ray; ions; showed	A novel surface modification technique was developed to provide a copper nickel alloy (M) surface with bactericidal and anticorrosion properties for inhibiting biocorrosion. 4-(chloromethyl)-phenyl tricholorosilane (CTS) was first coupled to the hydroxylated alloy surface to form a compact silane layer, as well as to confer the surface with chloromethyl functional groups. The latter allowed the coupling of 4-vinylpyridine (4VP) to generate the M-CTS-4VP surface with biocidal functionality. Subsequent surface graft polymerization of 4VP, in the presence of benzoyl peroxide (BPO) initiator, from the M-CTS-4VP surface produced the poly(4-vinylpyridine) (P(4VP)) grafted surface, or the M-CTS-P(4VP) surface. The pyridine nitrogen moieties on the M-CTS-P(4VP) surface were quaternized with hexylbromide to produce a high concentration of quaternary ammonium groups. Each surface functionalization step was ascertained by X-ray photoelectron spectroscopy (XPS) and static water contact angle measurements. The alloy with surface-quaternized pyridinium cation groups (N+) exhibited good bactericidal efficiency in a Desulfovibrio desulfuricans-inoculated seawater-based modified Barr's medium, as indicated by viable cell counts and fluorescence microscopy (FM) images of the surface. The anticorrosion capability of the organic layers was verified by the polarization curve and electrochemical impedance spectroscopy (EIS) measurements. In comparison, the pristine (surface hydroxylated) Cu-Ni alloy was found to be readily susceptible to biocorrosion under the same environment.
10.1080-08927022.2019.1602868	-1		Polycrystalline materials like Cu-Pb alloy consist of four types of microstructural components, including grain cells, grain boundaries, triple junctions and vertex points, the mechanical properties of which governed by the atomic proportion of the alloy elements to a certain degree. The internal stresses from such microstructural components are quite different. Due to experimental limitations, the internal stresses from the alloy materials are difficult to measure directly, especially in the microstructural components. Here, we report a bottom-up approach using an atomistic calculation to obtain atomic properties in Cu-based alloy, as well as that in the microstructural components. The results reveal that a steep stress gradient exists at the interfaces of the alloy, which decreases significantly with the increase of the Pb. The defects evolution process in the alloy samples are investigated during tensile loading, revealing that the defect nucleation is delayed due to the decreasing von Mises stress gradient in the interfaces region as Pb increased. And the increased hydrostatic pressure in the interfaces regions, as a secondary factor can promote the defect nucleation. Among alloy samples with a grain size of 18.58 nm, that with 6.6 at% Pb has minimal defects and the best mechanical properties.
10.1080-08927022.2022.2042532	-1		Inspired from natural materials, functionally graded materials (FGMs) with gradual variations in their compositions and microstructures have drawn considerable attention in structural materials design to achieve superior stiffness, strength, and toughness. Taking Cu-Ni alloy as a representative model system, herein, we systematically explore the mechanical properties of Cu-Ni FGMs with varying Ni distributions and Ni contents, respectively, where the lattice constant of Cu-Ni FGMs is found to decrease with increasing Ni content. By carrying out uniaxial tension and compression, it is observed that Young's modulus of Cu-Ni FGMs is nearly independent of the atomic distribution profile but sensitive to the Ni content. Yield stress also shows the strong dependency of Ni content; under the same Ni content, however, due to the sharpness of the interface and different deformation mechanisms, the yield stress becomes sensitive to the Ni distribution. Remarkably, there exists a tension-compression (T-C) asymmetry in Cu-Ni FGMs-the T-C asymmetry of yield stress is more heavily influenced by Ni distribution and content compared to Young's modulus. Our study provides fundamental insights into the mechanical response of Cu-Ni FGMs with varying Ni distribution profiles and contents from an atomic perspective, aiding in the computational design of FGMs.
10.1080-09276440.2021.1904720	-1		Using Fe reaction products to overcome the poor wettability between copper and carbon, C/Cu-Fe composites with excellent properties were prepared by gas pressure infiltration technique. The elemental Fe, being distributed between carbon and Cu, reacted with carbon to form Fe3C layer and effectively improved the wettability of the C/Cu system. The contact angle decreased from 124 degrees to 21 degrees. Compared to composites without Fe doping, the C/Cu-Fe composites exhibit significantly higher compressive and flexural strengths, as well as electrical resistivity reaching six times better than the industry standard requirement. Microstructure analysis indicates that the continuous tight Fe3C interlayer with moderate thickness at the C/Cu interface has a bridge effect on the interfacial bonding enhancement.
10.1080-09276440.2022.2046940	-1		Copper-graphite composites synergetic reinforced by nano-carbon (multi-walled carbon nanotubes (MWCNTs), graphene nanoplatelets (GNPs)) and ceramic particle reinforced phases (Al2O3 particles and hexagonal boron nitride (HBN)) with alloying elements were fabricated through Spark Plasma Sintering for friction material. The surface modification of MWCNTs and GNPs treated with gallic acid and rutin solutions with ultrasonic treatment can improve the dispersibility. The interfacial bonding between the matrix and the reinforcing phase in the composites was mainly mechanical, and the diffusion layer can be observed. The content of MWCNTs and GNPs remained 1 wt%; as the proportion of MWCNTs increased, the mechanical properties of nano-carbon and ceramic particles reinforced Cu-graphite composites gradually increased. With the content of 0.8 wt%MWCNTs-0.2 wt%GNPs, the composites had the best performance, and the relative density, hardness and compressive strength were 96.01%, 42.75 HV and 202.37 MPa, respectively. According to the morphology of compression fracture, the fracture type was a brittle fracture. It can be determined that the strengthening mechanisms of the composites were mainly load transfer, particle strengthening and fine grain strengthening.
10.1080-095008300176263	-1		High-resolution transmission electron microscopy and conventional transmission electron microscopy have been used to investigate in detail the transformation processes of twinned 9R copper precipitates to final stable structures via a 3R structure in a thermally aged Fe-Co model alloy. In 9R precipitates of size greater than about 13 nm, the motion of the twin boundaries and the elimination of the regular stacking faults on every third (009)(9R) close packed plane were observed to occur nearly simultaneously. Direct evidence was found that 3R is a non-cubic structure obtained when the regular stacking faults on the (009)(9R) basal planes are removed. In larger precipitates (of size up to about 26 nm), lattice plane rotations and plane spacing changes in 3R variants took place towards stable fee and fct structures, suggesting the occurrence of lattice relaxation involving the diffusion of atoms. The fct structure had larger lattice constants a = b = 0.369 nm and c = 0.366 nm than bulk fee copper (a = 0.361 nm). Precipitates of;size 26-40 nm consisted of nearly twin-related variants with both fee and fct. segments, and aligned with the iron matrix according to the Kurdjumov-Sachs orientation relationship. Larger precipitates were observed to be fee and fct single crystals.
10.1080-0950083031000066126	11	glass; bulk; metallic; bulk metallic; gfa; bmg; glassy; metallic glass; ability; bulk metallic glass; amorphous; addition; crystallization; mm; glass-forming	Cu55Zr30Ti10Co5 bulk metallic glass exhibits a high compressive fracture strength of 2.31 GPa and Young's modulus of 130 GPa, values that are higher than those of other Cu- and Zr-based metallic glasses. The addition of Co to the ternary Cu-Zr-Ti alloy stabilizes the supercooled liquid. On heating, the Cu55Zr30Ti10Co5 metallic glass devitrified and formed an intermediate intermetallic compound prior to reaching equilibrium by diffusion-controlled growth at constant nucleation rate. In the fully annealed state the structure consists of the equilibrium Cu10Zr7 phase with the slightly reduced lattice parameters a = 0.933 nm, b = 0.928 nm and c = 1.254 nm and a small fraction of an unidentified phase.
10.1080-09500830500164278	-1		The transformation of second-phase particles in a Cu-Fe alloy following equal-channel angular extrusion and annealing has been determined by transmission electron microscopy. Equal-channel angular pressing of the Cu-Fe alloy transformed coherent gamma-Fe particles in the Cu matrix into incoherent alpha-Fe. Upon annealing, numerous coherent gamma-Fe particles were observed. A dislocation-particle interaction mechanism is suggested to explain the re-precipitation of coherent gamma-Fe particles following annealing.
10.1080-09500830500421488	-1		A stress-oriented formation of plate-shaped Guinier-Preston (GP) zones in single crystals of a Cu-0.9 wt% Be alloy aged at 200 degrees C has been found. A compressive stress applied in the [ 001] direction assists the formation of the GP zones perpendicular to the [ 001] axis, while a tensile stress results in the preferential formation of the GP zones parallel to the stress axis. The applied stress strongly affects the nucleation of the GP zones. Free ageing at 275 degrees C after compressivestress ageing at 200 degrees C produces plate-shaped gamma '' precipitates perpendicular to the stress axis, indicating a continuous change in the structure of the GP zones into that of the gamma '' phase. From length-change measurements during ageing, the misfit strains of the GP zone or gamma '' precipitate in directions parallel and perpendicular to the plate plane are estimated, respectively, as-0.01 and-0.10 for the GP zone and-0.01 and-0.11 for the gamma '' precipitate.
10.1080-09500830701576312	-1		The anomalous temperature dependence of the critical resolved shear stress (CRSS) of Cu-Ni alloys observed below a certain temperature, To 50 K, has been accounted for by introducing a stress-concentration factor f(T) [(T' + T-o)/(T' + T)] in the monotonic CRSS-T formulation of the kink-pair nucleation model of solid-solution hardening. The empirical constant T ' is found to depend not only on the solute concentration, c, but also on the nature of the solute distribution in the host lattice. It is found that the solute distribution is random for c <= 14 at% Ni in the Cu lattice and for c <= 20 at% Cu in the Ni lattice, whereas some sort of local ordering occurs for all other values of solute concentration.
10.1080-09500830701591493	-1		In situ transmission electron microscopy observations are reported of the dynamic process of twin boundary migration in Cu with nanoscale twins. The experiment provides the first direct evidence of twin boundary migration via Shockley partial dislocation emission from the twin boundary/grain boundary intersections, and reveals that such migration is the dominant deformation mechanism in the initial stage of plastic straining. The behaviour is discussed in comparison with molecular dynamics simulations and in terms of the unique characteristics of the sample microstructure.
10.1080-09500830802537700	-1		The influence of prior cold work (90% reduction) on the length change and precipitation behaviour of a Cu-1.8wt%Be-0.2wt%Co alloy aged at 320C up to 350 h has been investigated. The alloy gradually expands to a maximum and then contracts during ageing. The maximum expansion is attributable to both the expansion due to the loss of Be solute atoms and the contraction due to precipitation of the [image omitted], I, m and ' phases. The subsequent contraction results from the decrease in amounts of the [image omitted] and m phases and the increase in amount of the ' phase. The new-found m phase, consisting of alternate Be and Cu matrix layers parallel to the matrix {001}, is body-centred monoclinic with a = b = 0.263 nm and c = 0.279 nm and = 83, and aligns with the matrix according to the Bain orientation relationship. The Guinier-Preston (GP) zone transforms continuously to the m or I phase via '' and [image omitted]. The transformation from the GP zone to ' via '', [image omitted] and I is retarded in comparison with that for the un-deformed alloy.
10.1080-09500830903236038	-1		We have fabricated micro-/nano-pillars of two metallic glasses (MGs), Cu-based Cu47Ti33Zr11Ni6Sn2Si1 and Zr-based Zr50Ti16.5Cu15Ni18.5, respectively, with pillar tip diameters ranging from similar to 650 to similar to 90 nm. These pillars were mechanically tested in situ in transmission electron microscopy as a function of pillar diameters. It turns out that the yield strengths of both MGs are close to those of the bulk glasses and are essentially size independent. Statistical physics description of strength for small size metallic glass is discussed.
10.1080-09500839.2010.486755	-1		The shape evolution of fcc Co-Fe precipitate particles during coarsening in Cu-1.37 at% Co-0.83 at% Fe alloy single crystals has been examined by the transmission electron microscopy observation. Co-Fe particles change from sphere to cuboid and eventually flatten into a plate-like one with increasing particle size. The size-dependent equilibrium shapes of Co-Fe particles were discussed by considering the elastic strain energy of particles together with the interface energy between the particles and the matrix. To evaluate the elastic strain energy, elastically homogeneous but anisotropic particles with purely dilatational misfit strains are taken into account. The experimentally observed shape transition can be satisfactorily explained by the simple energy analysis.
10.1080-09500839.2010.533132	-1		In this study, bulk nanostructured composite Cu60Fe40 alloy is prepared by a combustion synthesis technique. The prepared Cu60Fe40 alloy consists of Cu(Fe) solid solution and Fe(Cu) solid solution phases. The large-scaled compositional segregation in the Cu-rich and Fe-rich phases is not observed, respectively. A few micron-sized dendrite (Fe(Cu) solid solution) is embedded into the nanostructured matrix (Cu(Fe) solid solution). The grain size of the matrix is in the range 50-300 nm. The yield and fracture strength of the Cu60Fe40 alloy are 540 and 1050 MPa, respectively, and the fracture strain obtained from the compression test is about 20.9%. The Cu60Fe40 alloy displays notable work hardening in the compressive deformation.
10.1080-09500839.2012.682169	-1		A study has been conducted on a Cu(Sn) solid solution to examine the role of the vacancy wind effect on interdiffusion. First, the interdiffusion and the intrinsic diffusion coefficients are calculated. The trend of the interdiffusion coefficients is explained with the help of the driving force. Following this, the tracer diffusion coefficients of the species are calculated with and without consideration of the vacancy wind effect. We found that the role of the vacancy wind is negligible on the minor element in a dilute solid solution, which is the faster diffusing species in this system and controls the interdiffusion process. However, consideration of this effect is important to understand the diffusion rate of the major element, which is the slower diffusing species in this system.
10.1080-09500839.2013.835079	-1		It is known that the binary Cu-2wt% Be alloy can be strengthened by ageing its supersaturated solution at 523K. The increase in the strength arising from ageing is because of the formation of GP zones. The same level of strength is achieved by ageing the supersaturated solid solution of a dilute binary Cu-4wt% Ti alloy at 723K. In contrast to Cu-2wt% Be alloy, the increase in strength in this alloy occurs on account of spinodal decomposition of the as-quenched microstructure through the mechanism of clustering and ordering. In the present study, decomposition of a supersaturated solid solution of the ternary Cu-4wt% Ti-2wt% Be alloy was studied. Whereas ageing of this alloy at 523K resulted in the formation of GP zones like in a Cu-2wt% Be alloy, ageing at 723K resulted in a spinodally decomposed microstructure as in a Cu-4wt% Ti alloy. The decomposition of the ternary alloy at the two temperatures by two different mechanisms indicates that Be and Ti in solution in Cu act, more or less, independently of each other during ageing.
10.1080-09500839.2013.861944	16	wear; composite; composites; powders; milling; particles; powder; wt; sliding; friction; hardness; matrix; mechanical; surface; properties	The grain size variation in a gradient surface produced by a punching and recovery process on a Cu-30Ni alloy has been observed by atomic force microscopy. The friction characteristics of the gradient surface in a 3.5 wt% NaCl solution were investigated using a micro-indenter probe, a pin-on-disc type tribometer, a strain sensor and an optical microscope. The results showed that the hardness and grain size can be well represented by the Hall-Petch relationship when the gain size is more than 30nm. The wear rate, friction coefficient and adhesive force all increase depth below the surface. These variations are attributed to a gradual increasing grain size with depth . The morphologies of the worn track were also studied to understand further the corrosive wear behaviour of gradient surfaces.
10.1080-09500839.2014.926033	-1		Dissociated dislocations introduced by plastic deformation in a Cu-13.43 at% Al alloy 38 years ago have been examined by transmission electron microscopy. The dislocations were found to extend widely and it is concluded that the Suzuki effect is responsible for the widening.
10.1080-09500839.2015.1122242	-1		A modified grain size-dependent model developed to capture the combined effects of solute and grain size on the work hardening behaviour of fine-grained Cu-Ni alloys is provided. This work builds on a recent model that attributes the grain size-dependent work hardening of fine-grained Cu to backstresses. In the case of Cu-Ni alloys, unlike commercially pure Cu, a grain size-dependent separation between the Kocks-Mecking curves develops, this being explained here based on an extra contribution from geometrically necessary dislocations in the solid solution alloy. This is corroborated by strain-rate sensitivity experiments.
10.1080-09500839.2018.1463108	-1		Metastable-state alloy powders are usually synthesised by milling and occur as products of mechanical alloying (MA), but they are rarely used as starting materials for other MA processes. In this work, metastablestate alloy powders, including supersaturated solid-solution Cr(Mo)s and amorphous Cr(Mo)a were prepared in advance. Then, the Cr(Mo)s/Cr(Mo)a powder mixture was mechanically alloyed with elemental Cu to form Cu-Mo-Cr alloy. The effects of the metastablestate powder Cr(Mo)s/Cr(Mo)a on MA of the immiscible Cu-Mo-Cr system were evaluated. Phases and microstructures of the milled powders were analysed by XRD and TEM, respectively. The results show that amorphous Cu-60wt% Cr(Mo) and supersaturated solidsolution Cu-20wt% Cr(Mo) alloy powders can be synthesised by MA. It is concluded that MA of the Cu-Mo-Cr ternary alloy system is significantly promoted when elemental Cu powder is milled with metastable-state alloy powder Cr(Mo)s/Cr(Mo)a. Furthermore, the promoting effect of amorphous Cr(Mo)a on MA the Cu-Mo-Cr alloy system is much greater than that of supersaturated solid-solution Cr(Mo)s, during the milling process.
10.1080-09500839.2024.2302628	-1		The formation mechanism of a recrystallisation internal friction (IF) peak superimposed on a grain boundary (GB) IF peak for deformed copper was studied. The P1 peak, associated with the recrystallisation process, was observed at similar to 599 K (2 K/min) during the first heating process. Subsequently, the P2 peak, located at similar to 510 K (0.2 Hz), corresponded to GB relaxation during the cooling process. The P1 peak showed minor relaxation at higher frequencies owing to the influence of GB relaxation. To accurately determine the temperature of the P1 peak in this scenario, two methods were used: fitting the measured IF spectra and performing IF measurements at lower frequencies and/or with faster heating rates to minimise the impact of GB relaxation. This work investigated the formation mechanism of the recrystallisation peak and supplemented the method for determining the recrystallisation temperature through IF measurements when the GB peak occurs at a nearby temperature.
10.1080-10402004.2013.870271	17	wear; composites; coating; friction; composite; coatings; surface; tribological; properties; wear resistance; resistance; powder; sliding; matrix; wear rate	Copper matrix composites reinforced with MgO, Al2O3, SiO2, and SiC nanoparticles were fabricated by powder metallurgy. The tribological properties of the composites were examined using a self-made pin-on-disk electrical wear tester. Thermal expansion properties of the prepared composites were evaluated by their coefficient of thermal expansion from 50 to 500 degrees C. The effect of the thermal expansion characteristics of reinforcements on the electrical wear performance of the composites was also studied. The results showed that the wear rates of MgO/Cu and Al2O3/Cu composites were lower than those of SiC/Cu and SiO2/Cu composites, which were also consistent with the difference between the coefficient of thermal expansion of the copper matrix and reinforcements. The relationship was analyzed by calculation of the thermal stress at the copper matrix-reinforcement interface in the electrical sliding process. Microstructural observation revealed that the wear mechanisms of the copper matrix composites were mainly adhesive wear and plastic deformation accompanied by a small amount of arc damage.
10.1080-10402004.2021.1992063	17	wear; composites; coating; friction; composite; coatings; surface; tribological; properties; wear resistance; resistance; powder; sliding; matrix; wear rate	The present study investigated the effect of TiB2 on the tribological properties of CuSn10Bi3 bimetallic bearing materials. CuSn10Bi3 samples with different contents of TiB2 were fabricated by powder sintering technology. Their metallographic structures and tribological characteristics under different working conditions were analyzed and compared. The results showed that TiB2 refined the copper alloy grains, passivated the grain boundary edges, and reduced the surface porosity of the sample. When the content of TiB2 was 1%, the wear rate under different oil conditions (oil-rich, oilless, and dry friction) was reduced by 42-95%. The sharp decrease in the wear rate was attributed to the enhancement of the micrograin structure of the copper alloy matrix material by TiB2 hard particles with antiwear properties and the high hardness and high wear resistance of TiB2. The wear tracks were analyzed using scanning electron microscopy and energy-dispersive spectroscopy, and it was concluded that the addition of TiB2 enhanced the wear resistance.
10.1080-10420159908229090	7	irradiation; shear; grain; ta; deformation; size; radiation; voids; nanocrystalline; simulations; similar; void; temperature; irradiated; boundaries	This paper consists of two parts. In part 1, the experimental results of damage evolution of neutron-irradiated Cu and Ni are described. In part 2, results of computer simulations are described with linkage of experimental data to explore the atomistic process of damage evolution. To study experimentally the atomistic processes of damage evolution in neutron-irradiated Cu and Ni in part 1, we prepare two types of specimens for both metals. One is as-received specimen from manufacturer. Another is a residual-gas-free specimen which is prepared by melting as-received metals in highly evacuated vacuum at 10(-5) Pa. Specimens are irradiated with fission neutrons in the temperature-controlled-irradiation capsule at JMTR (Japan Materials Testing Reactor). TEM (Transmission Electron Microscope) observation shows that the dislocation structure is developed by the aggregation of interstitial clusters in irradiated metals. It is found that the number density of void which are observed in specimens, both as-received and residual-gas-free, that are irradiated to a low fluence such as 5.3 x 10(18) n/cm(2) at high temperature of 200 degrees C is the same. This suggests that gas atoms are not responsible for the nucleation of voids at high temperature above 200 degrees C in neutron-irradiated Cu and Ni. There are two characteristic temperatures of T-sft and T-void for the formation of stacking fault tetrahedra (sfts) and voids at high temperature, below T-sft only sft forms and above T-void only voids are observed. T-sft is 180 degrees C and 250 degrees C for Cu and Ni, respectively. T-void is 250 degrees C and 270 degrees C for Cu and Ni, respectively. In situ annealing experiments of neutron-irradiated specimen are carried out to examine the behavior of voids and sfts at high temperature. It is found that voids move as a cluster and that sfts coalesce and disappear spontaneously without shrinkage of their size. In part 2, Computer simulations of molecular dynamics and molecular statics are carried out to study the atomistic process of damage evolution in neutron-irradiated Cu and Ni at high temperatures. Interstitial clusters relax to a bundle of [110] crowdions and move one-dimensionally with a small activation energy such as 0.001 eV. The migration of interstitial bundles reacts sensitively to strain fields. Interstitial clusters then form their grouping. The activation energy of an interstitial bundle to change their crowdion direction to another one is about 1 eV. This is an important factor for the evolution of dislocation structure. At high temperatures, a vacancy cluster of sfts and voids relaxes to a movable structure of string shape. Vacancy clusters move and coalesce with other clusters. The activation energy is as small as those that vacancy clusters move as a cluster without an evaporation as a single vacancy. Voids can nucleate at high temperature without trapping of any gas atoms in small vacancy clusters. Voids nucleate uniformly in specimens irradiated to a low fluence. Microvoids migrate under the influence of strain fields and segregate near dislocation lies. At high temperature, vacancy clusters relax to the movable structure of string shape. This may explain the results of recent varying temperature irradiation at high temperature. At high temperature, vacancies are stored in a supersaturated state in a crystal as small vacancy clusters and clustering of vacancies proceed by cluster migration.
10.1080-10420159908229100	3	sma; shape; shape memory; memory; smas; superelastic; bars; damping; cu-al-mn; mechanical; bending; applications; numerical; sma bars; material	In crystalline solids, ductility and strength are known to be governed by generation of dislocations and their motion either by glide or climb. Meanwhile, a transmission electron microscope (TEM) has been developed as an indispensable tool for studying the microstructures of crystalline solids used for various purposes. Topics related to the dislocation structures may be examined most critically by TEM observations, especially by stereo microscopy using a high voltage electron microscope. The present paper describes various types of dislocation sources, dislocation glide and climb, dislocation-dislocation interactions, and the resultant effects on the structure and strength . Brief review is made on these subjects with visual evidence obtained by TEM observations. The materials we focus on are: Al-Cu alloys stressed after quenching, Fe based shape memory alloys, Ll(2) ordered alloys for high temperature use and Al based amorphous alloys with high strength/weight ratio.
10.1080-10426910701236056	16	wear; composite; composites; powders; milling; particles; powder; wt; sliding; friction; hardness; matrix; mechanical; surface; properties	Kinetics of solid-state reduction reaction during ball milling of CuO-Al and CuO-prealloyed Cu( Al) powder blends in dry and wet condition has been investigated by using X-ray diffraction ( XRD), differential scanning calorimetry ( DSC), and transmission electron microscopy ( TEM) techniques. Direct reduction of CuO by Al has resulted into Al2O3 dispersed Cu-matrix composite through a self-propagating reaction only during milling in dry condition. However, indirect reduction of CuO by prealloyed Cu( Al) resulted into formation of nano-Al2O3 dispersed Cu-matrix composite either by continued ball milling in dry condition or by subsequent thermal treatment of wet milled powder precursor. The influence of milling conditions, that is, milling speed, and milling media, on the occurrence of reduction of CuO by elemental Al or Al in prealloyed Cu( Al) during ball milling have been explained by considering their effects on the rise of powder temperature due to collisions between balls and powder particles, and the rate of reduction of ignition temperature of the reaction due to microstructural refinement. TEM investigation has revealed that the size of Al2O3 particles in the composite power blend formed by the indirect reaction route ( CuO-prealloyed Cu( Al)) is much finer than the same in case of direct reaction route ( CuO-Al). It is suggested that the kinetics of the reduction reaction in the indirect reaction route is relatively sluggish in nature and amenable to processing of large amount of nano-Al2O3 dispersed Cu- matrix composite powder for industrial purpose.
10.1080-10426914.2013.852222	2	corrosion; surface; film; electrochemical; films; spectroscopy; layer; current; solution; potential; resistance; composition; x-ray; ions; showed	To prevent premature failure of heat exchanger tubes enduring rapid seawater flow, amorphous electroless Ni-P coatings were prepared on copper-nickel alloy (CuNi 90/10) substrates. The influence of post-deposition vacuum heat treatment at different annealing temperatures (190, 300, 400, 500, and 600 degrees C) on the erosion-corrosion resistance of the annealed coatings was examined by X-ray diffraction, scanning electron microscopy, potentiodynamic polarization, and electrochemical impedance spectroscopy. It was found that precipitation of a crystalline phase took place in the coating matrix at 400 degrees C. The highest microhardness was achieved for coatings undergoing heat treatment at 400 degrees C due to the formation of the stable Ni3P phase. Electrochemical results indicated that all the Ni-P coatings present passivity and better corrosion resistance than the uncoated CuNi 90/10 substrate. The Ni-P coating treated at 500 degrees C demonstrated the best erosion-corrosion resistance, which represented the optimization of the balance between erosion and corrosion resistance.
10.1080-10426914.2014.984210	-1		In this paper, a new application of equal channel angular pressing (ECAP) for fabrication of Cu-Al bimetallic tubes is presented. For the evaluation of ECAP effects, the microstructure and micro-hardness of samples are considered. To investigate of bonding properties of Cu-Al tubes, optical microscopy and shear strength testing were used. In addition, the effect of friction coefficient and thickness on applied force was evaluated by numerical analysis. The results from the experiments indicated that the hardness of Cu and Al increased by 156.8 and 129%, respectively. Also, the average Cu grain size after three passes fell from 62.5 to 11.2 mu m. Finally, Cu and Al tubes were well interconnected as a bimetallic tube at higher passes.
10.1080-10426914.2015.1070412	16	wear; composite; composites; powders; milling; particles; powder; wt; sliding; friction; hardness; matrix; mechanical; surface; properties	In the present research, composite electrode (Cu-Mn) manufactured through powder metallurgy has been used to machine hot die steel (H11) by electrical discharge machining (EDM) process with the aim of inducing manganese and carbon into the machined surface. Such alloying is expected to improve the microhardness and other surface characteristics. Best level of process parameters for better surface finish and high microhardness are found using Taguchi method. Six processing parameters are considered and their significance is investigated by analysis of variance. Techniques like energy dispersive spectroscopy, scanning electron microscopy, and X-ray diffraction are used to ascertain the surface characteristics. Surface machined at optimum process conditions for microhardness shows 93.7% improvement due to formation of cementite, ferrite and manganese carbide phases. Surface roughness having Ra value of 3.11 mu m has been achieved.
10.1080-10426914.2019.1594259	16	wear; composite; composites; powders; milling; particles; powder; wt; sliding; friction; hardness; matrix; mechanical; surface; properties	In the current investigation, solid-lubricant surfaces were prepared onto the mild steel work piece by means of electrical discharge coating process in electrical discharge machine (EDM). Hexagonal boron nitride (hBN) and copper (Cu) powder-based green compact electrodes, prepared in hot mounting press were used as an EDM tool. The loosely bonded material particles from the compact tool were transported to the mild steel surface. With the change of process parameters (powder mixture ratio, duty factor, and peak current), the variation in surface morphology, micro-hardness and tribological properties of hBN-Cu coating layer has been discussed. Following the investigation, field emission scanning electron microscopic (FESEM) images of coating indicated fewer gaps and pores for the powder lubricant mixing ratio of hBN: Cu/50:50, peak current value of 10 A and duty factor value of 70%. X-ray diffraction plot composed of prominent peaks of BN, Cu, along with Fe2O3 (intermetallic compound). Micro-hardness value of lubricant surfaces drastically reduced to the minimum of 75.76 HV (coating layer) from 180 HV (substrate). Moreover, pin on disk tribological test indicated the lubrication effect of hBN particles by revealing a major drop in wear value from 95.75 mu m (work piece) to 1.52 mu m (coating) and friction coefficient from 0.9 (work piece) to 0.1 (coating).
10.1080-10426914.2019.1605179	16	wear; composite; composites; powders; milling; particles; powder; wt; sliding; friction; hardness; matrix; mechanical; surface; properties	The surface properties of machine components are enhanced by surface modification. The workpiece surface can be modified using electro discharge machining (EDM) process. In this paper, mild steel work surface was modified by EDM operation using copper-multiwalled carbon nanotube (Cu-MWCNT) composite-coated 6061Al electrode. Five different electrodes (uncoated, Cu coated, Cu-MWCNT (0.5, 0.75, and 1 gL(-1)) composite-coated 6061Al electrode) were used for machining of mild steel work in order to compare the EDMed surface. The microstructure, elemental composition analysis, microhardness, and surface roughness of EDMed surface were investigated. The microstructural and elemental compositional analyses indicated that the MWCNTs were included into the mild steel workpiece during EDM operation. The microhardness (HV) of machined surface was enhanced by 163% compared to the base mild steel. The micro-crack formation on machined surface was significantly decreased by using Cu-MWCNT composite-coated 6061Al electrode.
10.1080-10426914.2020.1718700	-1		Polycrystalline diamond (PCD) is widely used for its excellent properties but difficult to be processed by traditional machining methods. Electrical discharge machining (EDM) is regarded as an important method to machine PCD because of its non-contact nature. In this study, copper-nickel (Cu-Ni) electrode was prepared by electrodeposition and used to machine PCD. The machining characteristics of PCD including surface morphology, material removal rate (MRR) and surface roughness (SR) were studied in detail. Results show that the surfaces processed by Cu-Ni electrode have a larger radius but shallow craters and less cracks than that by Cu electrode. The MRR of PCD by Cu-Ni electrode is 252% higher than that by Cu electrode, and the SR is 18% lower than that by Cu electrode after processing at low parameter value while they are 6% and 15% at high parameter value, respectively. The result indicates that graphitization of diamond dominates the removal process when processing by Cu-Ni electrode; however, when processing by Cu electrode, the principal cause of the diamond exfoliation was the fusion of the cobalt binder and explosion. This research provides an essential experimental basis for designing technics of precision and highly efficient electrical discharge machining PCD tools.
10.1080-10426914.2020.1726948	-1		Laser remelting (LR) is a typical laser manufacturing technique. In this study, LR was used to fabricate gradient-structured CuNiBe alloy bars. A series of LR experiments with different parameters (such as the output power of the laser transmitter, scanning speed, and cooling condition) and subsequent aging treatments were designed. The remelted zone depth (RZD), the hardness with depth on the plane perpendicular to the LR track, the microstructure, and the precipitation characteristics of different zones of the remelted samples were analyzed. The results showed that the RZD increased with a higher output power of the laser transmitter and lower scanning speed. The hardness of the CuNiBe was significantly improved by the LR and subsequent aging treatment. A remelted zone (RZ) and heat affected zone (HAZ) were found in the remelted surface layer, and equiaxed substructures and columnar substructures were present in the RZ. Well-dispersed NiBe precipitates on the substructure boundaries in the transitional area between the RZ and HAZ were the main cause of strengthening of the sample that underwent LR without water-cooling. The strengthening effect was significantly enhanced by the refined grains for the sample that underwent LR with water-cooling.
10.1080-10426914.2022.2105888	-1		Fabrication, characterization, and thermomechanical reliability of electroplated Cu-Sn-Cu-based transient liquid phase (TLP) bonding required in microsystems packaging are reported. Die-level bonding was achieved using 8-mu m-thick electroplated copper pillars covered with 2-mu m tin. A mechanical test specimen having rectangular ring-shaped structures was fabricated to measure the strength of Cu-Sn joints. An electrical test vehicle having 250 copper pillars connected in a daisy chain series was designed. The effect of bonding force, temperature, and durations on the shear strength and electrical resistance of the Cu-Sn-Cu joints were investigated. The mechanism behind the improved bonding at higher force, temperature, and duration is reported. Samples bonded at a lower bonding force (5 kg) failed, while those bonded at a higher force showed good strength . A complete transformation of Sn into stable Cu3Sn was essential to achieve good bonding. Due to the presence of Cu3Sn IMC, the bonding strength of samples bonded at higher temperatures and longer duration was higher. Thermal shock and humidity tests were conducted to check the long-term reliability of Cu-Sn-Cu bonded joints. The percentage change in the electrical resistance of a complete daisy chain remained <5% even after 1000 thermal shock cycles.
10.1080-10584587.2011.575649	-1		Cu/Zn alloy films were DC-sputtered on flexible acrylic resin-coated PET substrates and the effect of sputtering condition on the morphology and growth rate of Cu/Zn alloy films were investigated. It is found that long sputtering time, low voltage and large target-to-substrate distance can lead to smooth and uniform films. Chamber pressure must be well controlled at several Pascal. High voltage, short target-to-substrate distance and media chamber pressure can improve the growth rate of Cu/Zn alloy films. The suitable DC sputtering condition is 1.6 kV of voltage, 25 mm of target-to-substrate distance, 10 Pa of chamber pressure and 20 min of sputtering time, under which the as-prepared Cu/Zn alloy films possess of smooth surface and 41 nm of thickness.
10.1080-13621718.2023.2173878	-1		In dissimilar brazing, the differences in physical properties between the components lead to residual stresses. An active filler alloy Cu-20.5Sn-20Ag-3.5Ti was developed to braze the Cu-Al2O3 composites (containing 25 and 50 volume pct. Al2O3) to copper. Two mechanisms were proposed for chemical bonding as a result of alumina reinforcements reduction by the active titanium, including the formation of Ti-3(Cu,Al,Sn)(3)O layer beside the Ti2O in Cu/Cu-25%Al2O3 joints; and the solidification of Ti-3(Cu,Al,Sn)(3)O in the vicinity of TiO layer/Cu4Ti islands in the Cu/Cu-50%Al2O3 joints. Some intermetallic compounds such as Cu3Ti2 and Cu41Sn11 are formed/coarsened with an extra increase in brazing temperature. An increase in brazing time improves the thickness of the TiOx layer with no sensible effect on Ti-3(Cu,Al,Sn)(3)O width .
10.1080-13640461.2016.1158963	0	solidification; phase; magnetic; magnetic field; undercooling; field; liquid; separation; peritectic; immiscible; cu-; dendrite; phase separation; microstructure; primary	The influence of temperature conditions on the grain refinement of pure Cu solidified with low-voltage pulsed magnetic field (LVPMF) was investigated. With the pouring temperature (T-p) and mould temperature (T-m) increasing, the solidified microstructure of pure Cu was gradually changed from fine equiaxed grains to coarse columnar grains and then to the mixed structure of coarse equiaxed grains and columnar grains. Little change was observed from the microstructure of pure Cu solidified with and without LVPMF for the low T-p and T-m. But for the high T-p and T-m, applying LVPFM remarkably reduced the coarse columnar grains and obtained fine equiaxed grains. The grain refinement by LVPFM is considered to be caused by the electromagnetic flow. The smaller cooling rate resulted by higher T-p and T-m offers much acting time for LVPMF and thus better grain refinement can be achieved.
10.1080-13640461.2017.1290910	-1		The growth restriction factor Q of the alloying elements of the Cu-system was determined using thermodynamic software tools to obtain accurate Q-values. A comprehensive list was given for a nominal solute content of 1 wt-%. Based on the calculations, melting experiments were carried out under defined casting conditions given by the TP-1 test to evaluate the correlation between Q and grain size in Cu alloys.
10.1080-13640461.2017.1367527	0	solidification; phase; magnetic; magnetic field; undercooling; field; liquid; separation; peritectic; immiscible; cu-; dendrite; phase separation; microstructure; primary	Cu-Fe binary alloys containing 20-50wt. % Fe were studied by the combination of the melt fluxing and cyclic superheating technique. The microstructural evolution of Cu-Fe alloys was investigated with scanning electron microscopy. When the undercooling was larger than the critical undercooling, the Fe-rich spheroids were embedded into a Cu-rich matrix and the metastable phase separation was observed in microstructures. The size of separated particles in the Cu-35wt% Fe alloy was larger than that of other Cu-Fe alloys with different compositions and the size of separated droplets was related to the Delta T-S, which was equal to the undercooling (Delta T) minus the critical undercooling (Delta T-C). Moreover, a large undercooling tended to promote the coagulation of the separated droplets, so the size of the separated Fe-rich spheroids in the microstructure of the immiscible Cu-Fe alloys increased with the increase in the undercooling.
10.1080-13640461.2018.1522022	-1		Large-scale fabrication of Cu36Zr48Al8Ag8 amorphous alloy sheets having with lengths above 250 mm was performed using atmosphere-controlled twin roll strip casting. By constructing a continuous cooling transformation diagram, the critical cooling rate was determined to be 212.6 K/s. The size and morphology of the crystalline phases within the amorphous matrix, which was Al-rich and Ag-depleted, were confirmed by scanning electron microscopy. The presence of a small volume fraction fine dendritic crystalline phase was necessary for the improved plasticity of the amorphous strip under tensile deformation mode.
10.1080-14686996.2024.2309888	-1		To solve poor engineering performance of copper-tungsten alloys operated at high temperatures, 3D network tungsten frameworks were prepared using a selective laser melting (SLM) process, and then copper was melted and diffused into these tungsten network structures to form copper matrix composites with different copper contents (i.e. Cu-10vol%W and Cu-30vol%W). Their mechanical/electrical properties and arc ablation performance were characterized. Results showed the obtained CuW composites were dense with good interfacial bonding, and the connected Cu phases formed a heat conduction channel and improved electrical and thermal conductivities of the composites. Electrical conductivities of Cu-30W and Cu-10W composites were 44.7% and 80.3% IACS, and their thermal conductivities at 25 degrees C were 247.5 and 375.4 W/(mK), respectively. The W-skeleton grid structure in the composites showed enhanced effects on impact toughness and anti-friction/wear resistance. Tensile strengths of Cu-30W and Cu-10W composites measured at 300 degrees C were 95 MPa and 135 MPa, and their impact toughness values were 11.25 and 15.25 J/cm(2), respectively. For the arc ablation performance, the copper phase of CuW composite was identified as the key influencing phase, whereas the W skeleton effectively hindered the spread of arc spots, inhibited quick melting of copper phases, and played effective support and protection functions.
10.1080-1478422X.2019.1619289	2	corrosion; surface; film; electrochemical; films; spectroscopy; layer; current; solution; potential; resistance; composition; x-ray; ions; showed	Field exposure test was carried out to investigate the sea water corrosion behaviour and rules of T2 and 12832 copper alloy materials in different sea areas. The corrosion morphology characteristics and corrosion products properties were analysed using different techniques, and the main environmental factors influencing their corrosion rates were discussed by applying grey relational analysis. Reaults showed that with the decrease of the latitude, the corrosion rate of T2 increased, and grey relational analysis indicated that temperature had a significant influence on it. For 12832 copper alloy, the corrosion rate was lower than that of T2 on the whole. Different degree of biofouling occurred on 12832 copper alloy, and the surface fouling conditions (including sediment deposition) had a crucial impact on its corrosion behaviour. In summary, 12832 copper alloy had a better corrosion resistance, but accompanied by de-Mn and de-Al corrosion.
10.1080-1478422X.2021.1988386	2	corrosion; surface; film; electrochemical; films; spectroscopy; layer; current; solution; potential; resistance; composition; x-ray; ions; showed	Electrochemical tests and surface analyses were carried out to study the influence of the external low-voltage spatial electric field (SEF) on the corrosion behaviour of copper in 3.5 wt-% NaCl solution and explore the corrosion kinetics of copper under the SEF. The results show that the presence of the SEF aggravated the corrosion of copper; the results of weight loss tests and electrochemical tests indicated the enhanced corrosion rate of copper as the field strength increased. The X-ray diffraction results of corrosion products suggested that the Cu2O converted to Cu-2(OH)(3)Cl with application of the SEF. The effect of the SEF on the copper proved the increase in corrosion rate was attributed to the enhanced migration of ions towards the sample surface caused by the external SEF. It resulted in more aggressive chloride ions to penetrate into the looser surface corrosion product film, thereby accelerating corrosion.
10.1080-1478422X.2022.2060789	2	corrosion; surface; film; electrochemical; films; spectroscopy; layer; current; solution; potential; resistance; composition; x-ray; ions; showed	The corrosion behaviour of Ti alloy TA8-1, Cu alloy B19 and Cu are studied under simulated early deep geological conditions of Beishan, China. In the short-term experiment, the influence of temperature on the corrosion properties of the studied materials is investigated by electrochemical impedance spectroscopy (EIS), potentiodynamic polarisation and cyclic polarisation. In the long-term immersion tests, the evolution of corrosion behaviour is investigated by EIS, in combination with SEM, XPS and Raman analysis. The results show that Ti alloy TA8-1 has the minimum corrosion current density (10(-7) A cm(-2)) and low pitting susceptibility, attributed to the formation of a thin passive film. Cu has the relatively high corrosion current density (similar to 10(-5) A cm(-2)) and low pitting susceptibility. The corrosion resistance of the Cu2O/Cu-2(OH)(3)Cl deposit layer is maintained during the two-month immersion test at 50 degrees C. Severe localised corrosion occurs on the surface of B19 and the corrosion resistance deteriorates obviously during the immersion test.
10.1080-1478422X.2023.2247661	2	corrosion; surface; film; electrochemical; films; spectroscopy; layer; current; solution; potential; resistance; composition; x-ray; ions; showed	The electrodeposited antimony-copper coatings demonstrate a varying degree of chemical and structural heterogeneity that determines their corrosion behaviour in 0.5M sodium chloride. The electrochemical and corrosion properties of layers at open circuit potential were investigated by electrochemical impedance spectroscopy and optical surface observation. Corrosion polarisation tests revealed that anodic behaviour of Sb-Cu alloys is similar for the all tested samples and depends on the antimony chemical resistance. Under anodic polarisation up to about -0.03 V-Ag/AgCl a multistep process of anodic oxide film transformation was registered. The observations by SEM revealed that at a higher anodic polarisation many submicron-sized pits are formed. The formation of microgalvanic corrosion cells results in preferential dissolution of the antimony phase at both OCP and anodic polarisation.
10.1080-14786430601096928	-1		The glass-forming ability (GFA) of an alloy in this case is the largest diameter of a rod which can be cast fully glassy. The present work shows that the thermal conductivity of a liquid alloy has a strong effect on GFA by influencing the cooling rate upon mould casting. The initial cooling rates ( for the first 70-100 K of temperature decrease), obtained for Cu-, Zr- and Au-based bulk glass-forming alloys in the liquid state, are found to scale linearly with the thermal conductivities of the liquid base elements. However the low cooling rate found for Ni-based alloy suggests that the heat transfer at the melt-mould interface may also influence the cooling rate. The low thermal conductivity of Ni-based alloys and the correspondingly low cooling rate obtained compared to Cu- based counterparts explains their lower GFA. In the literature, many factors influencing the GFA of alloys have been discussed. To these factors, the present study adds the thermal conductivity of the molten alloy and the melt-mould heat-transfer coefficient. Moreover, the cooling rate depends on temperature and, thus, the critical cooling rate itself is not a suitable parameter for indicating GFA. The cooling can be better described by an appropriate fitting of the cooling curve to an exponential temperature decay function.
10.1080-14786430802375634	6	grain; deformation; strain; strength; dislocation; cu-; tensile; size; ecap; grain size; sfe; ductility; hardening; high; stress	The cyclic deformation behaviour of polycrystalline Cu, Cu-10 wt% Zn and Cu-32 wt% Zn was systematically investigated in the plastic strain amplitude range of 1 x 10(-4)-4 x 10(-3). The differences in the cyclic stress-strain (CSS) responses and fatigue cracking behaviour between Cu, Cu-10 wt% Zn and Cu-32 wt% Zn were compared. It was found that the occurrence of a cyclic saturation for Cu-10 wt% Zn and Cu-32 wt% Zn strongly depends on the applied strain amplitude, whereas polycrystalline Cu always displays cyclic saturation. Surface deformation morphologies were analyzed by scanning electron microscopy (SEM). One of the major features observed is that the slip bands become increasingly homogenous with Zn addition. The fatigue cracks were found to frequently nucleate along the annealing twin boundaries (TBs) in Cu-10 wt% Zn and Cu-32 wt% Zn, but not in polycrystalline Cu. Based on these experimental results, the cyclic deformation response and fatigue cracking behaviour are discussed, and a developed TB cracking mechanism is proposed to explain the difference in fatigue cracking mechanisms in Cu, Cu-10 wt% Zn and Cu-32 wt% Zn.
10.1080-14786430802607085	13	clusters; atomic; glass; atoms; composition; dynamics; metallic; icosahedral; glasses; simulations; molecular; cu-zr; molecular dynamics; metallic glasses; structural	The electrical resistivity and absolute thermoelectric power of the liquid Cu-x-Bi(1-x) system have been measured over the whole composition range from the liquidus to 1100 degrees C. The thermal conductivity is deduced from measurements of these two properties. The experimental results are interpreted and discussed in term of the extended Faber-Ziman formula using the t-matrix formalism with hard-sphere structure factors. The concentration and energy dependence of the phase shifts have been taken into account for a complete conductivity and thermopower calculation.
10.1080-14786430903019040	6	grain; deformation; strain; strength; dislocation; cu-; tensile; size; ecap; grain size; sfe; ductility; hardening; high; stress	For single and quasi-single phase metallic materials, complete dynamic recrystallization has been observed in the nugget zones (NZs) of friction stir welds (FSWs), producing fine and uniform equiaxed grains. In this study, partial dynamic recrystallization was observed in the NZ of 5 mm thick friction stir welded brass plates. Whereas the top and the advancing side of the NZ were characterized by fine completely-recrystallized grains, the remaining region consisted of coarse non-recrystallized deformed grains, annealed recrystallized grains and deformed recrystallized grains. The occurrence of partial recrystallization was attributed to the inhibiting effect of a high volume fraction of fine beta'-phase particles. Increasing the FSW passes reduced the fraction and size of non-recrystallized deformed grains, but could not eliminate the partially recrystallized zone completely.
10.1080-14786430903352631	-1		The influence of an applied stress on discontinuous precipitation (DP) in a Cu-2.1 wt% Be alloy aged at 300 degrees C was examined. A compressive stress accelerates the growth of DP cells, which consist of lamellae of the precipitated g phase and the solute-depleted a phase, but a tensile stress does not essentially change it. The cell growth rates along the loading direction under the compressive and tensile stress are identical to those along the direction perpendicular to the loading direction under the same stress. Both the compressive and tensile stresses have no influence on the incubation time to initiate DP. From measurements of the specimen length change and investigations of the distribution of g variants in cells in a particular case, specific g variants among crystallographically equivalent ones are found to be formed, depending on the sense of the applied stress. This result, together with the dependence of the cell growth rate on the sense of the applied stress, can be well understood through the interaction energy between the external stress and the misfit strains of discontinuous g precipitates.
10.1080-14786431003630892	4	transformation; martensite; martensitic; phase; shape; beta; memory; shape memory; temperature; temperatures; martensitic transformation; gamma; transformation temperatures; effect; thermal	Phase transformations in a single-crystal Cu-Al-Ni shape-memory alloy induced by thermomechanical effects were investigated in situ by high-resolution synchrotron X-ray microdiffraction. Contrary to the common belief, austenite texture maps revealed that austenite-to-martensite transformation occurred during heating of the partially transformed material under fixed specimen elongation. Twinned and detwinned types of martensite coexisted during this austenite-to-martensite phase transformation. Twinning and detwinning structures evolved to accommodate changes in stress and strain generated in the temperature-varying environment. Small amounts of austenite exhibiting distorted crystallographic orientation were detected in regions of stress-induced martensite during heating of the partially transformed material. The results of this investigation provide insight into intriguing stress rate-dependent phenomena intrinsic of shape-memory alloys and elucidate complex phase transformations due to thermal and mechanical stress effects.
10.1080-14786431003745401	4	transformation; martensite; martensitic; phase; shape; beta; memory; shape memory; temperature; temperatures; martensitic transformation; gamma; transformation temperatures; effect; thermal	The martensitic transformation was investigated in a set of twin roller melt-spun Cu-Zn-Al shape memory alloys, solidified at tangential wheel speeds between 20 and 40 m/s. The resulting microstructures were analyzed using X-ray diffraction, optical and transmission electron microscopy techniques. The characteristic martensitic transformation temperature, MS, was determined for each condition by conventional resistometric methods. The ribbons are homogeneous in shape and for each quenching rate they exhibit a quite uniform MS temperature. By proper thermal treatments, the different factors affecting MS could be separately examined and from temperature measurements, the contribution of L21 antiphase boundaries evaluated. A calculation of this contribution using pair interchange energies is in good agreement with the experimental results.
10.1080-14786435.2010.509287	-1		The new crystal structure of an orthorhombic phase formed at the alloy composition Cu48.1Al36.4Sc15.5 was analyzed by means of the Rietveld method using synchrotron radiation diffraction data. The starting model for this analysis was constructed theoretically using the so-called 'cell constrained melt-quenching technique'. The space group of the final model is Cmmm, and the unit cell includes 49.0 Cu, 39.0 Al and 16.0 Sc atoms. The lattice parameters are a = 8.337(4) angstrom, b = 22.02(1) angstrom and c = 8.305(4) angstrom, which are related to the six-dimensional lattice parameter, a6D = 6.959 angstrom, of the corresponding Cu-Al-Sc icosahedral quasicrystal as 1/0, 2/1 and 1/0 approximations, respectively. The characteristics of the structure can be understood as a framework consisting of Sc atoms, which is regarded as a tiling of five local structural units; the largest is an icosahedron similar to that included in the Tsai-type quasicrystal. The second exhibits structural similarity to a Mg2Zn11-type crystal and the third is an octahedron.
10.1080-14786435.2012.658878	-1		An investigation by high-resolution transmission electron microscopy of the precipitation process during ageing a Cu-1.2 wt%Be-0.1 wt%Co alloy at 320 degrees C has revealed that the transition phases follow a gamma '' -> gamma '' + gamma ' -> gamma sequence. The gamma ' phase heterogeneously precipitates on the gamma '' phase. The effects of an external stress on the nucleation and growth of disc-shaped gamma '' and plate-shaped gamma ' precipitates have been examined for the alloy aged at 320 degrees C. A compressive stress applied in the [001] direction during ageing preferentially accelerates the nucleation and growth of the gamma '' variant normal to the [001] axis among three crystallographically equivalent variants and the specific four gamma ' variants formed on the gamma '' variant normal to the [001] axis. A tensile stress does not significantly affect those of gamma '' and gamma ' precipitates. The critical diameter of the disc-shaped gamma '' nucleus is estimated as about 1 nm from evaluation of the interaction energy between the applied stress and the misfit strains of gamma '' precipitates. It is proposed that applied external stress does not affect the diffusion rate but the interphase boundary velocity.
10.1080-14786435.2012.659008	13	clusters; atomic; glass; atoms; composition; dynamics; metallic; icosahedral; glasses; simulations; molecular; cu-zr; molecular dynamics; metallic glasses; structural	We have used the X-ray absorption fine structure method and molecular dynamics (MD) simulations to characterize atomic order in Cu-Zr metallic glasses (MGs). The microstructure of these MGs is described in terms of interconnected icosahedral-like clusters (superclusters) which are basic building units reproducing the stoichiometry of the system. The equilibrium MD configurations are used as an input for ab initio calculations of the extended X-ray absorption fine structure (EXAFS) and X-ray absorption near-edge structure (XANES) spectra. The theoretical EXAFS and XANES spectra are compared with those measured for rapidly quenched glassy Cu-Zr alloys. We demonstrate that the experimental results are well reproduced by EXAFS modeling of the population of the superclusters derived from the MD configuration. The average local structural motif can be approximated by Cu-centered icosahedral-like cluster satisfying the condition of maximal local packing efficiency and approximating the system stoichiometry. The simulated XANES exhibits good agreement with experiment, indicating that the atomic order of the MD configuration is consistent with that of the real alloy structure over distances of about 1 nm.
10.1080-14786435.2012.735771	11	glass; bulk; metallic; bulk metallic; gfa; bmg; glassy; metallic glass; ability; bulk metallic glass; amorphous; addition; crystallization; mm; glass-forming	The effect of microalloying with rhenium on a metallic glass-forming alloy (Cu46Zr46Al8)100 x Re x (x=1,2) was investigated. Re possesses a positive enthalpy of mixing within the CuRe terminal system. Splat quenched foils of approximate to 40 mu m in thickness display an amorphous structure. Their crystallisation temperature increases from T x=504 to 513 degrees C with addition of Re at nearly constant glass formation temperature T g=445 degrees C for the amorphous samples. In contrast, injection cast rods consist of B2-CuZr type phase dendrites, minor fractions of a cubic phase CuZrAl, and randomly distributed small particles of a Re-rich phase. This represents a novel concept in microalloying where Re-rich precipitates trigger the B2 phase formation. It leads to a unique combination of mechanical properties for as-cast rods, which display high strength at sizeable plastic deformation up to epsilon p approximate to 4% and an extended range of work-hardening prior to failure.
10.1080-14786435.2012.750767	-1		Precipitating phases in a supersaturated Cu-8.6at% Sn alloy annealed at 573K have been studied by using transmission electron microscopy. Three Hume-Rothery (HR) phases, , and E were identified in the matrix, each with distinct morphologies. The phase emerges in the form of rhombic precipitates inside grains with an orientation relationship (OR): . The phase emerges both inside grains and at grain boundaries. Frequently observed OR is . Intragranular particles consistently satisfy this OR; while it is proposed that a cellular morphology, whose details have been reported separately, develops only when this condition is satisfied for precipitates at grain boundaries. The E phase emerges along {111} planes inside grains with a planar morphology. These plates exhibit two types of ORs: . and . The latter is the OR, reported for the same alloy annealed at 593K. These findings are discussed from the viewpoints of the layer structures of the respective HR phases. It was shown that both the atomic configuration and interlayer spacing of the and phases match well with {111}, while the E phase cannot satisfy these two conditions simultaneously, resulting in one of the two ORs.
10.1080-14786435.2014.1000418	-1		Grain-size dependency of deformation twinning has been previously reported in nanocrystalline face-centred-cubic metals, which results in an optimum grain-size range for twin formation. Here, we report, for the first time in experiments, the observed optimum grain sizes for deformation twins in nanocrystalline Cu-Zn alloys which slightly increase with increasing Zn content. This result agrees with the reported trend but is much weaker than predicted by stacking-fault-energy based models. Our results indicate that alloying changes the relationship between the stacking-fault and twin-fault energy and therefore affects the optimum grain size for deformation twinning. These observations should be also applicable to other alloy systems.
10.1080-14786435.2014.892223	-1		Copper and niobium are mutually immiscible in the solid state and exhibit a large positive enthalpy of mixing in the liquid state. Using vapour quenching via magnetron co-sputter deposition, far-from equilibrium amorphous Cu-Nb films have been deposited which exhibit a nanoscale phase separation. Annealing these amorphous films at low temperatures (~200 degrees C) initiates crystallization via the nucleation and growth of primary nanocrystals of a face-centred cubic Cu-rich phase separated by the amorphous matrix. Interestingly, subsequent annealing at a higher temperature (>300 degrees C) leads to the polymorphic nucleation and growth of large spherulitic grains of a body-centred cubic Nb-rich phase within the retained amorphous matrix of the partially crystallized film. This sequential two-stage crystallization process has been investigated in detail by combining transmission electron microscopy [TEM] (including high-resolution TEM) and atom probe tomography studies. These results provide new insights into the crystallization behaviour of such unusual far-from equilibrium phase-separated metallic glasses in immiscible systems.
10.1080-14786435.2014.951712	-1		High-resolution electron backscatter diffraction was employed to study the evolution of microstructure during friction stir welding of a typical low stacking fault energy material (Cu-30Zn brass) over a wide range of welding temperatures. In all cases, microstructure evolution was found to be governed by discontinuous recrystallization that occurred via grain-boundary bulging and subsequent recrystallization nucleation. This promoted drastic grain refinement and significant strengthening. The crystallographic textures that evolved were typically dominated by a A/A {1 1 1 1} <100> simple shear texture.
10.1080-14786435.2015.1091110	-1		The structural properties, phase stabilities, anisotropic elastic properties and electronic structures of Cu-Ti intermetallics have been systematically investigated using first principles based on the density functional theory. The calculated equilibrium structural parameters agree well with available experimental data. The ground-state convex hull of formation enthalpies as a function of Cu content is slightly symmetrical at CuTi with a minimal formation enthalpy (-13.861kJ/mol of atoms), which indicates that CuTi is the most stable phase. The mechanical properties, including elastic constants, polycrystalline moduli and anisotropic indexes, were evaluated. G/B is more pertinent to hardness than to the shear modulus G due to the high power indexes of 1.137 for G/B. The mechanical anisotropy was also characterized by describing the three-dimensional (3D) surface constructions. The order of elastic anisotropy is Cu4Ti3 > Cu3Ti2 > -Cu4Ti > Cu2Ti > CuTi > -Cu4Ti > CuTi2. Finally, the electronic structures were discussed and Cu2Ti is a semiconductor.
10.1080-14786435.2015.1112442	-1		A Cu-TiC alloy, with nanoscale TiC particles highly dispersed in the submicron-grained Cu matrix, was manufactured by a self-developed two-step ball-milling process on Cu, Ti and C powders. The thermostability of the composite was evaluated by high-temperature isothermal annealing treatments, with temperatures ranging from 727 to 1273 K. The semicoherent nanoscale TiC particles with Cu matrix, mainly located along the grain boundaries, were found to exhibit the promising trait of blocking grain boundary migrations, which leads to a super-stabilized microstructures up to approximately the melting point of copper (1223 K). Furthermore, the Cu-TiC alloys after annealing at 1323 K showed a slight decrease in Vickers hardness as well as the duplex microstructure due to selective grain growth, which were discussed in terms of hardness contributions from various mechanisms.
10.1080-14786435.2017.1303577	-1		To obtain a direct non-magnetic analogy to Ni-Mn-Ga 10M martensite with highly mobile twin boundaries, we present the recalculation of twinning systems in Cu-Ni-Al martensite. In this approach, the twinning planes denoted as Type I, Type II and compound have similar orientations for both alloys (Ni-Mn-Ga and Cu-Ni-Al). In Cu-Ni-Al, compound twinning exhibits the twinning stress of 1 to 2 MPa comparable to twining stress of Ni-Mn-Ga. In contrast Type II twinning stress of Cu-Ni-Al is approximately 20 MPa, i.e. much higher than twinning stress for Type II in Ni-Mn-Ga (0.1 to 0.3 MPa). Similarly to Ni-Mn-Ga, the twinning stress of Type II in Cu-Ni-Al is temperature independent. Moreover, no temperature dependence was found also for compound twinning in Cu-Ni-Al.
10.1080-14786435.2017.1313466	-1		The role of Ni addition in Cu on the growth of intermetallic compounds in the Cu-Sn system is studied based on microstructure, crystal structure and quantitative diffusion analysis. The diffraction pattern analysis of intermetallic compounds indicates that the presence of Ni does not change their crystal structure. However, it strongly affects the microstructural evolution and diffusion rates of components. The growth rate of (Cu,Ni)(3)Sn decreases without changing the diffusion coefficient because of the increase in growth rate of (Cu,Ni)(6)Sn-5. For 3 at% or higher Ni addition in Cu, only the (Cu,Ni)(6)Sn-5 phase grows in the interdiffusion zone. The elongated grains of (Cu,Ni)(6)Sn-5 are found when it is grown from (Cu,Ni)(3)Sn. This indicates that the newly formed intermetallic compound joins with the existing grains of the phase. On the other hand, smaller grains are found when this phase grows directly from Cu in the absence of (Cu,Ni)(3)Sn indicating the ease of repeated nucleation. Grain size of (Cu,Ni)(6)Sn-5 decreases with further increase in Ni content, which indicates a further reduction of activation barrier for nucleation. The relations for the estimation of relevant diffusion parameters are established considering the diffusion mechanism in the Cu(Ni)-Sn system, which is otherwise impossible in the phases with narrow homogeneity range in a ternary system. The flux of Sn increases, whereas the flux of Cu decreases drastically with the addition of very small amount of Ni, such as 0.5 at% Ni, in Cu. Analysis of the atomic mechanism of diffusion indicates the contribution from both lattice and grain boundary for the growth of (Cu,Ni)(6)Sn-5 phase.
10.1080-14786435.2017.1324649	6	grain; deformation; strain; strength; dislocation; cu-; tensile; size; ecap; grain size; sfe; ductility; hardening; high; stress	The grain refinement and mechanical properties of a Cu-0.1Cr-0.06Zr alloy subjected to equal channel angular pressing (ECAP) at a temperature of 673K were examined. The microstructure evolution was characterised by the development of a large number of low-angle subboundaries at small strains. An increase in the true strain resulted in gradual transformation of low-angle subboundaries into high-angle grain boundaries that was assisted by the deformation micro-banding. The development of new ultra-fine grains was considered as a kind of continuous dynamic recrystallization, the kinetics of which was characterised by a sigmoid-type dependence on strain and could be expressed by a modified Johnson-Mehl-Avrami-Kolmogorov equation. ECAP led to significant strengthening of the alloy. The yield strength increased from 105MPa in the initial state to 390MPa after 8 ECAP passes. A modified Hall-Petch relationship was applied to analyse the contributions of grain refinement and dislocation density to the overall strengthening. In spite of significant strengthening, the electro-conductivity remained at a level of 80% IACS.
10.1080-14786435.2017.1341649	-1		The hierarchical distribution of Cu-rich precipitates (CRPs) and related partitioning and segregation behaviours of solute atoms were investigated in a 1.54 Cu-3.51 Ni (wt%) low-carbon high-strength low-alloy (HSLA) steel after multistage heat treatment by using the combination of electron backscatter diffraction (EBSD), transmission electron microscopy (TEM) and atom probe tomography (APT). Intercritical tempering at 725 degrees C of as-quenched lathlike martensitic structure leads to the coprecipitation of CRPs at the periphery of a carbide precipitate which is possibly in its paraequilibrium state due to distinct solute segregation at the interface. The alloyed carbide and CRPs provide constituent elements for each other and make the coprecipitation thermodynamically favourable. Meanwhile, austenite reversion occurs to form fresh secondary martensite (FSM) zone where is rich in Cu and pertinent Ni and Mn atoms, which gives rise to a different distributional morphology of CRPs with large size and high density. In addition, conventional tempering at 500 degrees C leads to the formation of nanoscale Cu-rich clusters in alpha-Fe matrix. As a consequence, three populations of CRPs are hierarchically formed around carbide precipitate, at FSM zone and in a-Fe matrix. The formation of different precipitated features can be turned by controlling diffusion pathways of related solute atoms and further to tailor mechanical properties via proper multistage heat treatments.
10.1080-14786435.2017.1401745	-1		Based on a limited energy storage viewpoint proposed by our team, it is assumed that there is a maximum constant value for the maximum storage of energy per unit volume when dislocation slip starts in a metal. A temperature-dependent critical resolved shear stress (CRSS) model without any fitting parameters is developed for metals in a pure shear mode. The CRSSs of Cu, Cu-Au, Cu-Co and Cu-Au-Co in the pure shear mode are predicted, and are in excellent agreement with the experimental results. This work offers an approach to predict the temperature-dependent CRSS for metals in the pure shear mode.
10.1080-14786435.2017.1414326	7	irradiation; shear; grain; ta; deformation; size; radiation; voids; nanocrystalline; simulations; similar; void; temperature; irradiated; boundaries	We conducted systematic experiments of defect structure development in Cu base binary alloys under 1000 kV electron irradiation at temperatures higher than 300 K, using in situ observations with high voltage electron microscopy. This report describes the effects of undersize elements: Co (-3.78%), Ni (-8.45%) and Be (-26.45%). The volume size factors are given in parentheses. The amounts of the respective elements were 2, 0.3, 0.05 at%, or less. In Cu-Ni and Cu-Co and in the reference Cu, temperature dependence of the number density of interstitial-type dislocation loops had a down peak (i.e. loops hardly formed) at approximately 373 K, attributed to unexpected impurity atoms. Above the down-peak temperature, the addition of Co or Ni increased the loop number density through continuous nucleation of loops, extended the loop formation to higher temperatures, and decreased the apparent activation energy of loop growth rate. The addition of Be for 0.3 at% or more delayed loop formation after formation of stacking fault tetrahedra (SFTs) around 300 K. The apparent mobility of self-interstitial atoms is expected to be smaller than that of vacancies because of strong binding with Be. Loop formation at temperatures higher than 373 K was enhanced by Be for 0.3 or 2 at%, although it was suppressed greatly for 0.05 at% or less. All undersize atoms increased the stability of SFTs under irradiation. Mechanisms of those effects were discussed and were briefly compared with earlier results found for oversize elements in Cu.
10.1080-14786435.2017.1415467	-1		A correlation between the change in magnetic susceptibility (Delta chi(exp)) upon crystallisation of Cu-Zr and Hf metallic glasses (MG) with their glass forming ability (GFA) observed recently, is found to apply to Cu-Ti and Zr-Ni alloys, too. In particular, small Delta chi(exp), which reflects similar electronic structures, ES, of glassy and corresponding crystalline alloys, corresponds to high GFA. Here, we studied Delta chi(exp) for five Cu-Ti and four Cu-Zr and Ni-Zr MGs. The fully crystalline final state of all alloys was verified from X-ray diffraction patterns. The variation of GFA with composition in Cu-Ti, Cu-Zr and Cu-Hf MGs was established from the variation of the corresponding critical casting thickness, d(c). Due to the absence of data for d(c) in Ni-Zr MGs their GFA was described using empirical criteria, such as the reduced glass transition temperature. A very good correlation between Delta chi(exp) and d(c) (and/or other criteria for GFA) was observed for all alloys studied. The correlation between the ES and GFA showed up best for Cu-Zr and NiZr2 alloys where direct data for the change in ES (Delta ES) upon crystallisation are available. The applicability of the Delta chi(exp) (Delta ES) criterion for high GFA (which provides a simple way to select the compositions with high GFA) to other metal-metal MGs (including ternary and multicomponent bulk MGs) is briefly discussed.
10.1080-14786435.2018.1436779	-1		Spinodal decomposition in Cu-9.4at%Ni-3.1at%Sn alloy was elucidated with the new insight from the experimental EXAFS analysis supported by ab initio total energy calculations suggesting the strong influence of the first near-neighbour atoms. Enthalpy of mixing was calculated for all crystallographically unique first near-neighbour configurations and finally an average positive enthalpy of mixing of 1604J/mol was obtained. Combination of ab initio results, XRD and EXAFS analysis indicate that one of the daughter phase becomes rich in Ni and Sn than the other phase; in contrary to the earlier proposition that Cu/Ni ratio remains constant in both daughter phases. It is also shown that the present thermodynamic description requires further refinement to extend the miscibility gap towards lower Ni content in Cu-Ni-Sn system.
10.1080-14786435.2018.1492751	12	thermodynamic; ternary; phase; data; experimental; equilibria; phase equilibria; liquid; binary; experimental data; calculated; phases; literature; model; calphad	In this work, the surface tension of Cu-Ti binary liquid alloys is calculated in the framework of Eyring theory as a function of composition and temperature. It is observed that for all investigated alloys the surface tension can be described by a linear function of the temperature with negative slope, and the temperature coefficient of surface tension decreases as Ti-content of the alloys increases linearly. The obtained theoretical results are compared to the experimental data available in the literature as well as to the theoretical results evaluated by using four models, such as the compound formation model, the quasi-chemical approximation for regular solutions, ideal solution model and Butler model treated in literature frequently.
10.1080-14786435.2018.1529443	-1		In the present work, new possibilities of the X-ray diffraction for investigations of the phase composition, size, shape and volume fraction of particles in ultrafine-grained ferritic/martensitic steel and the Cu-Cr-Zr alloy have been demonstrated. For the first time, the method of X-ray diffraction in the transmission mode was used to identify particles with a volume fraction of less than one percent in the ultrafine-grained materials studied. The small-angle X-ray scattering method was used to estimate the size and shape of dispersed particles. Specific features of the ultrafine-grained structure determined by the X-ray diffraction and transmission electron microscopy studies were used for estimation of dispersion hardening in the samples obtained by equal-channel angular pressing in comparison with the samples subjected to standard treatment.
10.1080-14786435.2018.1546958	-1		In this paper, the diffusion, thermodynamic and thermotransport properties in Cu-Ag liquid alloys are extensively investigated with molecular dynamics over a wide composition and temperature range. The simulations are performed with the most reliable EAM potential. The Green-Kubo formalism is employed for calculating transport properties. It is found that the reduced heat of transport in Cu-Ag is very small (about 0.10 eV in absolute value) and almost temperature independent. Further it is found that the interdiffusion coefficient together with both self-diffusion coefficients are almost composition independent. In Cu-Ag, the thermodynamic factor is found to be less than unity whereas the Manning factor is greater than unity (with significant composition and temperature dependence) and their product is very close to 1.
10.1080-14786435.2019.1703055	6	grain; deformation; strain; strength; dislocation; cu-; tensile; size; ecap; grain size; sfe; ductility; hardening; high; stress	The stored energy and activation energy for recrystallization were investigated for a Cu-Ni-Si alloy after high-pressure torsion processing for N = 1/2, 1, 5 and 10 turns at room temperature. The contributions of geometrically necessary dislocations (GNDs), statistically stored dislocations (SSDs) and vacancies to the stored energy were calculated through the Vickers microhardness measurements, kernel average misorientation (KAM) measurements and an analysis by differential scanning calorimetry (DSC). The results show that the total stored energy decreases rapidly after equivalent strain of epsilon(eq) similar to 9 and then saturates through epsilon(eq) similar to 86 at similar to 70 J/mol. Concurrently, the local stored energy in GNDs and SSDs was found to depend strongly on the radial distance from the centre of the disc and increase with increasing equivalent strain at epsilon(eq) similar to 16 and saturate with further straining. Accordingly, the results indicate that the GNDs and vacancies are responsible for the high stored energy in the initial stage of deformation at equivalent strain range of epsilon(eq) = 8.6-16 and thereafter their contribution decreases slightly due to the occurrence of dynamic recrystallization and the formation of fine grains. At the same time, the contribution of the SSDs is similar to that of the GNDs only in high strain deformation as at epsilon(eq) = 49.3 to accommodate the deformation process. An activation energy for recrystallization was estimated in the range of similar to 89.7-98.7 kJ/mol, thereby suggesting poor thermal stability.
10.1080-14786435.2021.1988173	-1		In this study, an experimental and atomic-scale simulation-based investigation has been performed to investigate the possible stability of the nano-crystalline structure and thereby considerable strength at a higher temperature in the case of synthesised Cu alloy along with logical understanding. Dispersions of high melting BCC metal (1 at% W) in nanostructured Cu is achieved using conveniently scalable cryomilling followed by hot pressing (at 550 degrees C). The thermal stability (till 800 degrees C) of grain size in synthesised nano-crystalline Cu alloy has been examined through X-ray diffraction (XRD) and Transmission Electron Microscopy (TEM). The nano-sized W particles dispersed at the Cu matrix grain boundaries, restricting grain growth by Zener pinning even after annealing was carried out at 800 degrees C. The hot-pressed pellets of nanocrystalline Cu99W1 alloy with a nearly uniform distribution of W particles have exhibited higher hardness than pure Cu and increased in strength and strain to failure up to 10% and 46%, respectively. The improvement in mechanical properties is further rationalised by the Molecular Dynamics (MD) based simulation findings.
10.1080-14786435.2021.2024617	-1		Cu-Ni-Al-Fe-Mn alloy billets were prepared by heating-cooling combined mould (HCCM) continuous casting at different casting speeds. Then, the cold deformation behaviour of billets was studied by multi-pass cold rolling, and the effects of HCCM continuous casting on cold deformability were discussed by comparing with the mould casting (MC) alloy. The results show that HCCM continuous casting significantly improves the cold deformability of Cu-Ni-Al-Fe-Mn alloy billets. When the rolling reduction is 94%, HCCM continuous casting samples have good edge quality without obvious crack, while the MC sample has severe edge cracks. With the rolling reduction increasing from 40% to 94%, the elongation of the MC samples decreases from 6% to 2%, while that of HCCM continuous casting samples maintains in 6%similar to 9%, showing good continuous deformability. The HCCM continuous casting samples with lower casting speeds have [001] oriented columnar grains along the casting direction, which make the deformation mechanism change from nano-crystallization to parallel stacking faults. In the meanwhile, HCCM continuous casting improves deformation coordination of as-cast grains and restrains intergranular cracking, which is reflected in the influence on misorientation between as-cast grains and distribution of coarse NiAl phases. In addition, nano-twins found in the rolled MC sample promote the initiation and propagation of cracks.
10.1080-14786435.2022.2122618	-1		Nanocrystalline alloy design with the synergistic contribution of 'thermodynamic' and 'kinetic' stabilisation mechanism leads to much superior microstructural stabilisation at elevated temperatures. Ternary Cu98.5W1Zr0.5 (at. %) alloy, synthesised by mechanical milling under cryogenic temperature followed by consolidation through hot pressing at 550 degrees C, has been examined to access the potential of their concurrence. A meager drop in hardness (similar to 0.5 GPa) confirms the stability of the alloy up to 800 degrees C. The effect of alloy addition has been studied in terms of microstructure alteration, measured by X-ray diffraction, transmission electron microscopy, and Molecular dynamics (MD) simulation. In addition, the shear punch test (SPT) has been employed to assess the mechanical property of the consolidated alloy. Results suggest that the current approach provides a framework en route to designing bulk nanostructured alloys adapting the bottom-up method.
10.1080-14786435.2023.2191018	15	aging; strength; conductivity; electrical conductivity; electrical; mpa; treatment; strengthening; degrees; cu-; cold; precipitation; tensile strength; tensile; iacs	The twin-roll strip casting (TRSC) process was introduced because of its sub-rapid solidification characteristics, and the element segregation and ageing precipitation of the Cu-6Ni-1.4Si-0.1Cr alloy were studied. The results are as follows: TRSC can effectively refine grain size and inhibit the segregation of the Cu-6Ni-1.4Si-0.1Cr alloy. Two types of precipitates are formed mainly during the ageing process: disk-shaped delta-Ni2Si and rod-shaped beta-Ni3Si. The comprehensive properties of the alloy are improved, and the precipitation strengthening mechanism is either from the dislocation shearing mechanism or the Orowan mechanism in different stages of ageing. The Cu-6Ni-1.4Si-0.1Cr alloy achieves optimum performance after ageing at 350 degrees C for 4 h, where the tensile strength and conductivity are 1112 MPa and 27.35% IACS, respectively. The Avrami equations were established for the alloy to describe the kinetics of phase transformation and electrical conductivity during ageing, and the calculated results are consistent with the experimental data.
10.1080-14786435.2023.2270489	15	aging; strength; conductivity; electrical conductivity; electrical; mpa; treatment; strengthening; degrees; cu-; cold; precipitation; tensile strength; tensile; iacs	The discontinuous precipitation behaviour and properties of Cu-Ti-Ni alloy during aging precipitation were studied by means of electron backscatter diffraction (EBSD), scanning electron microscopy (SEM), transmission electron microscopy (TEM) and X-ray diffraction (XRD). The results show that beta'-Cu4Ti was formed in the matrix during the aging process of Cu-4Ti-1Ni alloy, and the cellular structure grows at the grain boundary in the form of discontinuous precipitation in the middle and late stages of aging, and expands to the interior of the grains with the aging time until the grains were completely covered, then a uniform Cu3Ti structure was formed. In addition, the coverage area of cellular tissue increases with aging time and temperature. Under different aging temperature conditions, the hardness of the alloy increases first and then decreases with the aging time, with a peak value of 319.8 HV and a strength of 782.2 MPa. The electrical conductivity increases rapidly and then increases slowly with aging time, reaching 15.5 IACS after aging at 500 degrees C for 10 h . Based on the Avrami equation, the kinetic analysis of discontinuous precipitation at different temperatures was established.
10.1080-14786435.2023.2282023	6	grain; deformation; strain; strength; dislocation; cu-; tensile; size; ecap; grain size; sfe; ductility; hardening; high; stress	The influence of high-pressure torsion (HPT) and annealing on microstructure, texture and thermal stability of an immiscible composite Cu43%Cr alloy was studied using electron backscatter diffraction, X-ray diffraction and microhardness measurements. As-received alloy samples were subjected to HPT and subsequent annealing treatment in the range of 210-850 degrees C for 1 h in order to develop ultrafine-grained (UFG) microstructures and highlight their thermal stability. The Cu and Cr grains were refined to similar to 0.45 and similar to 0.39 mu m, respectively and exhibited equiaxed morphology. The crystallographic texture was of shear type in both Cu and Cr with the domination of C and F orientations, respectively. The UFG microstructure and texture were retained in the Cu43%Cr alloy up to 850 degrees C. The global results show that the immiscible composite Cu43%Cr alloy exhibits a high thermal stability up to 850 degrees C. The evolution of the microstructure, texture and thermal stability of the UFG Cu43%Cr alloy was compared to published data and available models.
10.1080-14786435.2024.2350572	6	grain; deformation; strain; strength; dislocation; cu-; tensile; size; ecap; grain size; sfe; ductility; hardening; high; stress	In this study, we investigated the microstructural evolution of a Cu-0.13Sn-0.04Mg alloy that underwent heat treatment followed by room temperature rolling (RTR). Initially heat-treated specimens were rolled at room temperature (RT) with reduction ratios (RR) of 40% and 75% to perform microstructural and crystallographic textural analyses. Electron backscattered diffraction (EBSD) and transmission electron microscopy (TEM) were utilise to examine both initial and deformed microstructures. Both exhibited heterogeneous microstructural distributions. Shear bands (SBs) existed in the initial specimen and became main sites for the nucleation of new grains during heat treatment. A denser presence of SBs was noted in the RTR specimens. Remarkably, an unusual self-annealing phenomenon was observed in these specimens, culminating in the emergence of recrystallized grains at RT. A plethora of such grains was observed in the severely deformed specimens, with numerous nucleating grains appearing proximal to the SBs or deformed grain boundaries (GBs). Time dependent microstructure evolution was observed via ex-situ EBSD technique in the compressed specimens. Formation of new grains, increase in high angle grain boundaries (HAGBs), and dislocation annihilations were observed with the progress of time. The crystallographic texture evolution in the initial specimen was predominantly influenced by the S component. At lower strains, the fractions of Copper component increased, whereas at higher strains, a greater fraction of Brass and S components were induced. Following a 40% RR, a saturation in hardness value was observed, which could be potentially attributable to an accelerated rate of RT recrystallization in the case of 75% RR.
10.1080-15361055.2022.2147765	-1		Laser powder bed fusion (L-PBF) of Glenn Research Copper 42 or 84 (GRCop-42 or GRCop-84) produces a Cr2Nb precipitation-hardened high-conductivity copper alloy with tensile strength superior to other competing copper alloys. Precipitate diameters within GRCop-42 gas-atomized powder increase with powder diameter due to slower cooling rates, however, unlike GRCop-84, no threshold diameter above which extensive precipitate agglomerations form was observed in GRCop-42. Large Cr2Nb crystals were observed in GRCop-42 powder particles, implying formation within the crucible melt. A consistent precipitate volume of similar to 7% over a range of powder particle diameters indicated a consistent atomization process. Occasional voids were observed in GRCop-42 powder. Precipitate size was refined in L-PBF GRCop-42 to a greater extent than in GRCop-84, improving Orowan strengthening, however, this benefit was lost after heat treatment due to greater coarsening of precipitates. Precipitates in GRCop-42 accumulated on grain boundaries during heat treatment to a greater extent than in GRCop-84.
10.1080-15376490490427162	4	transformation; martensite; martensitic; phase; shape; beta; memory; shape memory; temperature; temperatures; martensitic transformation; gamma; transformation temperatures; effect; thermal	In Part I of this study [1], group theory is used to describe the morphology and microstructure ( including the orientation relationships among lattice correspondence variants, habit plane variants and the self-accommodation diamond) of 2H martensite in shape memory alloys (SMAs). The microstructure of the habit and twinning planes and the orientation relationships among the lattice correspondence variants, habit plane variants, and self-accommodation plate groups are naturally categorized by means of group theory. In this study, the method developed in Part I [1] is used to study phase transformation from DO(3) austenite to 2H martensite in Cu-14.2Al-4.3Ni (wt%) shape memory alloy. The morphology and microstructure of this kind of martensite are demonstrated by graphic visualization.
10.1080-15376494.2021.1983678	-1		This work aims to study Cu films, and Cu-Co bilayer deposited using DC Magnetron sputtering system on silicon substrates. It can be seen that as the thicknesses of films were increased, the grain size becomes larger which was in good agreement with the presented SEM and AFM images. The high-intensity peak for FCC materials was generally (111) reflection, which is observed in the films when the Co-doping ratio was increased, the (111) peak became stronger. The PL spectra have shown that the Cu films with 70 nm Cu have a maximum value of the oxygen defect density however Cu-Co bilayer with 70 nm Co have a minimum value of the oxygen defect density. We found that the Cu-Co bilayer with 70 nm Co was more disordered and the disordering energy E-U in these bilayers was in a bout of 0.681 eV. The Cu-Co bilayers with 40 nm Co have maximum values of the energy gap about of 3.75 eV. The Cu-Co bilayers with 40 nm Co have maximum values of the electron-phonon interaction Ee-ph in about 0.0180 eV. The maximum value of the steepness parameter has occurred in Cu films with 70 nm Co and was 51.55 eV. It can be seen that the surface and volume dissipation factors in the Cu-Co bilayers with 60 nm Co have the maximum value. The maximum value of skin depth of films has occurred in Cu films with 60 nm Cu and it has a peak maximum about of 280 nm. The Cu-Co bilayers with 70 nm have maximum values of the average crystallite size about of 29.1 nm. Also, it is found that the Cu-Co bilayers with 70 nm have minimum values of micro strain epsilon. It can be observed that the relation between the optical band gap energy E-g and the Urbach energy E-u by E-g = 0.71-0.5E(u) were studied.
10.1080-17452759.2025.2458679	3	sma; shape; shape memory; memory; smas; superelastic; bars; damping; cu-al-mn; mechanical; bending; applications; numerical; sma bars; material	Shape memory alloys (SMA) are intelligent materials that could benefit from additive manufacturing, creating actuators with near-net-morphologies for each particular application. Herein, the complete processing route of a Cu-Al-Ni SMA through Laser Powder Bed Fusion (LPBF) is presented. Beginning from the design of the alloy and the atomization process, the strategy of LPBF is studied focusing on the optimization of the experimental parameters to obtain the highest compaction and optimal functional properties. The produced samples were characterized along the different steps of the processing route, including the thermal transformation, the microstructure and the functional shape memory and superelastic properties. Electron back-scatter diffraction analysis shows a columnar grains microstructure with a preferential [001] texture on the LPBF building direction, which has a noticeable effect on the functional properties. Fully recoverable superelastic effect of 2.7 % tensile strain, and shape memory recovery of +/- 4 % bending strain were obtained in LPBF processed samples. These functional performances are compared with those of a powder metallurgy reference sample, evidencing the enhancement of the superelasticity and shape memory obtained by the LPBF processing method. These results pave the road for producing Cu-Al-based SMA by additive manufacturing.
10.1080-17452759.2025.2522274	-1		Additive manufacturing offers substantial design freedom for developing copper (Cu) alloy components with complex shapes. However, the extreme process conditions of this technique increase the risk of solidification cracking. Cu-titanium (Ti) alloy, a high-strength Cu alloy, exhibited solidification cracks due to the Ti segregation at grain boundaries when processed with laser powder bed fusion, reducing the appeal of Cu-Ti alloys in the additively manufactured Cu market. In this study, we incorporated chemical fluctuations via in-situ alloying in laser powder bed fusion to suppress solidification cracks. These fluctuations promote the transformation from coarse columnar grains to fine near-equiaxed grains, thereby mitigating solidification cracks at grain boundaries. Furthermore, we discovered that the degree of chemical inhomogeneity decreased with reducing the elemental powder size of in-situ alloying. Utilising this novel strategy, we successfully in-situ synthesised Cu-Ti alloys devoid of solidification cracks and strengthened by cellular microstructures. Compared to Cu-Ti alloys without chemical fluctuations fabricated using pre-alloyed powders, in-situ synthesised Cu-Ti alloys exhibited significantly boosted tensile strength (from 306.3 MPa to 534.7 MPa) and fracture elongation (from 1.8% to 18.4%). This study presents a practical methodology to address the challenge of solidification cracking in some additively manufactured Cu alloys.
10.1080-19443994.2015.1024743	2	corrosion; surface; film; electrochemical; films; spectroscopy; layer; current; solution; potential; resistance; composition; x-ray; ions; showed	The paper describes an experimental study concerning the influence of major environmental parameters (temperature, chloride, carbon dioxide, and oxygen) on the corrosion behavior of 90/10 Cu-Ni alloys widely used for heat-transfer tubes. Electrochemical techniques have been used to investigate the corrosion behavior of 90/10 Cu-Ni alloys in aerated 3.5% NaCl solutions, at temperatures of 25, 50, and 80 degrees C with and without the injection of carbon dioxide. The results have revealed increases in chloride corrosion rates of the 90/10 Cu-Ni alloy with temperature and decreases with CO2 presence. Tests performed in aerated chloride-CO2 solutions have shown higher corrosion rates relative to those conducted in deaerated chloride solutions saturated with CO2 species. The surface morphology of polarized specimens in chloride solutions with and without CO2 presence has shown a susceptibility to pitting attack. Pit characteristics have been found to be highly influenced by CO2 presence.
10.1080-21663831.2014.911778	-1		Stress driven nucleation of nanocrystals in amorphous alloys has been a subject of intensive debate in the past decade. It has long been postulated that nanocrystals form succeeding the occurrence of shear bands in deformed amorphous alloys. In this study, we show, via in situ nanoindentation of amorphous Cu44Zr44Al12 alloy in a transmission electron microscope that the formation of nanocrystals occurred at an ultra-low stress of 0.25 GPa in the elastic deformation regime, accompanied by load-drops without evidence of shear bands. Furthermore, during successive loading, repetitive nanocrystal nucleation events were observed, and the stress required for nucleation kept on increasing to similar to 0.54 GPa, implying the occurrence of a 'hardening' effect in the amorphous alloy. This study provides direct evidence to advance our understanding on deformation-induced nanocrystallization of amorphous alloys.
10.1080-21663831.2015.1029645	-1		Increasing the fatigue strengths of high-strength materials, especially their endurance limits is essentially challenging. The fatigue strengths of nanocrystalline (NC) Cu and Cu-Al alloys processed by high-pressure torsion were prominently enhanced with a decrease in stacking fault energy. This remarkable escalation can be attributed not only to their significantly increased tensile strengths in macro-scale, but also to the essentially improved microstructure stability and reduced strain localization within shear bands in microscale. Owing to the limitation of their intrinsic fatigue mechanisms, the fatigue limits of NC Cu and Cu-Al alloys cannot always acquire appreciable improvement with their monotonic strengths.
10.1080-21663831.2015.1091795	-1		Cu-Ag alloys have much higher strength than that predicted by the usual mixture rule and attract intense attention. Although many researches on their strengthening mechanism were carried out, quantitative analysis of the ultra-strong strengthening effect of Ag precipitates is still a challenge. In this study, Cu, Cu-2 wt% Ag and Cu-6 wt% Ag were selected to bring to light the mechanism in remarkable strengthening effect of Ag alloying by relating the mechanical properties and the microstructure of the tested materials. A preliminary quantitative approach is proposed to predict the strength of Cu-Ag alloys with given composition and drawing strain.
10.1080-21663831.2016.1201160	7	irradiation; shear; grain; ta; deformation; size; radiation; voids; nanocrystalline; simulations; similar; void; temperature; irradiated; boundaries	Nanostructured Cu-Ta alloys show promise as high-strength materials in part due to their limited grain growth . In the present study, we elucidate the role of Ta on the transition from deformation twinning to dislocation-mediated slip mechanisms in nanocrystalline Cu through atomistic simulations and transmission electron microscopy characterization. In particular, computed generalized stacking fault energy curves show that as Ta content increases there is a shift from twinning to slip-dominated deformation mechanisms. Furthermore, heterogeneous twinnability from microstructural defects decreases with an increase in Ta. The computed effect of Ta on plasticity is consistent with the HRTEM observations. [GRAPHICS] IMPACT STATEMENT We show for the first time using atomistic simulations and TEM that, similar to grain size, the Ta nano-particles can be used to tailor the governing deformation mechanisms in NC-alloys.
10.1080-21663831.2018.1560370	-1		Effects of surface grain refinement and residual stress on the local and global properties of pure Cu processed using ultrasonic nanocrystalline surface modification (UNSM) was investigated. To distinguish each contribution to the local hardness and global tensile properties of the UNSM treated Cu, a stress-relief specimen of the same microstructure as the UNSM treated one was produced by low-temperature annealing after the UNSM treatment. The distinct contributions of residual stress and surface grain refinement to the tensile property of UNSM treated Cu were determined and discussed. IMPACT STATEMENTThe contributions of surface grain refinement and compressive residual stress on the enhanced local and global strengths of the UNSM-processed Cu were estimated as 80% and 20%, respectively. [GRAPHICS] .
10.1080-21663831.2022.2035838	-1		IMPACT STATEMENT TEM images and calculations revealed that Nb can stabilize metastable Cr3Cu precipitates (L1(2)) by reducing the Cu/Cr interfacial energy, and provide a higher high-temperature strengthening effect than b.c.c. Cr. Stable L1(2) structured Cr3Cu precipitates were determined in a Cu-4.06Cr-1.25Nb alloy rather than b.c.c. structured Cr precipitates by transmission electron microscope (TEM) and three-dimension atom probe tomography (3DAP) at 450 C-o. The precipitation sequence of the studied alloy aged at 400 C-o was supersaturated solid solution -> f.c.c. Cr phase -> Cr3Cu phase (L1(2)). Nb atoms would segregate in the interface between the Cu and Cr phase, reduce the Cu/Cr interfacial energy, affect the precipitation, growth, phase transformation, and coarsening of the precipitate. These Cr3Cu precipitates significantly improved the high-temperature strength of the Cu-Cr-Nb alloy (223 +/- 5 MPa at 500 C-o).
10.1080-21663831.2024.2319927	-1		Deformation twins (DTs) and stacking faults (SFs) are rarely found in Cu-20Ni-20Mn alloy, which limits further strengthening of alloy. Here, we report ultra-strong Cu-20Ni-20Mn alloy prepared by introducing a high density of coherent nanoprecipitates. The ultimate tensile strength (UTS) of alloy can be largely enhanced to 1624.7 +/- 14.7 MPa, while maintaining an acceptable elongation of 7.3 +/- 0.5%. We find that the coherent nanoprecipitates contribute to an ultra-high true stress up to about 1740 MPa, which facilitate the formation of DTs. The strength and ductility improvement stems from the synergistic effect of dislocations, nanoprecipitates and DTs.
10.1080-21663831.2024.2358964	14	strength; properties; conductivity; electrical; mechanical; cu-; grain; mpa; electrical conductivity; aging; precipitation; phase; mechanical properties; tensile; phases	Balancing the hardness and electrical conductivity of copper alloys within complex compositions and processes poses a formidable challenge. This study proposes a strategy combining machine learning with the Pareto front techniques to identify optimal combinations of composition and processing for Cu-xTi (1.5 <= x <= 5.4, in wt%) alloys. Through thermodynamic calculations, precipitation simulations, and experimental characterizations, the microstructural evolution of beta'-Cu4Ti precipitates in the designed alloys was explored. The interpretability and predictability of the machine learning model played a crucial role in understanding impact of complex alloy compositions and processing on the evolution of properties, thereby guiding the design of Cu-Ti alloys towards improved attributes.
10.1080-21663831.2024.2424933	-1		Designing new alloys with high performance is challenging due to the large search space for composition and process parameters. We propose an alloy design strategy based on machine learning algorithms for navigating the enormous search space. Specifically, feature engineering was applied to screen the major features, and a three-step alloy design strategy was employed to extract the required composition. The material design strategy for the multi-performance optimization of Cu-Ni-Si alloy through Bayesian optimization was proposed. This work provides novel insights into the comprehensive properties of Cu-Ni-Si alloys using machine learning with small data, with potential applicability to other materials systems.
10.1080-21663831.2025.2526101	-1		Cast Al-containing cupronickel alloys are strong, corrosion resistant and anti-bio fouling, yet suffering from poor ductility due to intergranular brittle phase and inhomogeneous intragranular precipitation. Here, we employ industrial accessible powder hot extrusion to achieve an ultrafine hierarchically microstructural tailoring of a Cu-17Ni-3Al based alloy, enabling an unprecedented strength-ductility combination (1.1 GPa ultimate strength with 21% elongation). The exceptional mechanical property is resulted from the homogeneous γ′ nanoprecipitates and heterogeneous matrix created by the interactions between fragmented G phase and dynamic recrystallization. These findings highlight the potential of heterostructure engineering with ordered nanoprecipitates for optimizing mechanical performance of Cu alloys.
10.1080-21870764.2020.1841073	16	wear; composite; composites; powders; milling; particles; powder; wt; sliding; friction; hardness; matrix; mechanical; surface; properties	This study aims to detect the positive effects of alumina coating by silver on the mechanical and tribological characteristics such as hardness and wear resistance of Al2O3 reinforced copper matrix nanocomposites. 2.5, 5, 7.5, and 10% wt. of alumina particles reinforced coated silver copper matrix nanocomposites were fabricated using the PM method. A scanning electron microscopy (SEM) was used to investigate the morphology of powders and microstructure of the nanocomposite samples. The density and hardness of samples were measured by the Archimede's method and Vickers microhardness method, respectively. Abrasive wear test of samples was measured using pin on disk. The results showed that coated alumina were homogenous distributed in the copper matrix. The densification of samples decreased but the hardness of samples increased with increasing Al2O3 content due to hard structure of Al2O3 ceramic particles. The highest microhardness was measured as 175 HV for copper matrix nanocomposites fabricated by using 10%wt of Al2O3 content. 70 HV was obtained for the copper matrix. Abrasive wear rate reduces by increasing the coated alumina percent and increase via increasing the normal load. In addition, the friction coefficient of the developed surface was found to decreasing with respect to increase coated alumina percent and increasing normal load.
10.1088-0022-3727-29-7-008	-1		Grain boundaries in copper doped with small amounts of bismuth have been examined by spatially resolved electron energy loss spectroscopy (EELS). The electron energy loss or x-ray absorption near edge structure (ELNES or XANES) yields information on the bonding state of the probed atoms. A white line was detected near the threshold energy of the bulk Cu-L(2,3) absorption edge when the electron probe is located within f nm of the grain boundaries. This spectroscopic feature provides direct evidence that the grain boundary influences the local electronic structure and may have implications on how Bi embrittles the grain boundaries in Cu. Effects are only observed in those boundaries where the presence of Bi was confirmed using energy dispersive x-ray EDX spectroscopy. Furthermore, no evidence was found to indicate, within detection sensitivity limits, any co-segregation of oxygen to these boundaries.
10.1088-0256-307X-30-7-076201	6	grain; deformation; strain; strength; dislocation; cu-; tensile; size; ecap; grain size; sfe; ductility; hardening; high; stress	The effect of temperature, T, on the ductility of nanocrystalline (NC) Cu films of different thicknesses on flexible substrates is studied by uniaxial tension. It is found that the NC Cu films will fracture more easily with increasing T, exhibiting the anomalous T effect compared with that of bulk NC metals and freestanding films. Moreover, the T dependence of ductility becomes stronger for thinner films due to the larger decrement of the interfacial strength in thinner films. T-induced softening of the stretchable substrate reduces the interface constraint ability for suppressing strain localization, leading to the anomalous T effect.
10.1088-0256-307X-37-8-086401	11	glass; bulk; metallic; bulk metallic; gfa; bmg; glassy; metallic glass; ability; bulk metallic glass; amorphous; addition; crystallization; mm; glass-forming	A new Cu-based bulk metallic glass composite of nominal composition (at%) Cu(41)Ni(27)Ti(25)Al(7)with excellent plasticity and a strong work-hardening behavior is fabricated. Strength above 1859 MPa and plasticity more than 11% are achieved under compression and tension modes. The deformation mechanism is proposed to the structural heterogeneities of the composite that promotes multiple shear bands meanwhile inhibits their free propagation, which results in the macroscopically plastic strain and work hardening. The alloy contains relatively cheap metals and has a low cost, which is beneficial to industrial applications.
10.1088-0953-2048-19-9-002	-1		Commercially available constantan alloy rods ( nominal composition Cu55-Ni44-Mn1 wt%) have been thermo-mechanically processed to develop biaxially textured substrates. It was found that the ( 001) recrystallization cube texture percentage could be increased from 72% to nearly 100% as the annealing temperature of the rolled substrates was increased from 750 to 1200 degrees C. A full width half maximum ( FWHM) of 6.5 degrees in ( 111) phi scans and an FWHM of 4.9 degrees in ( 100) omega scans were observed in the substrates annealed at 1200 degrees C for 2 h . These substrates were found to have a Curie temperature of 35 K and so were paramagnetic at 77 K and ferromagnetic at 5 K with a saturation magnetization that is 2.5 times less than that of Ni-5 at% W substrates. Yield strengths of highly textured constantan substrates were found to be 1.5 times that of textured pure Ni substrates at room temperature.
10.1088-0953-2048-20-6-009	-1		Screening dependence investigations of the superconducting state parameters (SSP), namely the electron-phonon coupling strength lambda, Coulomb pseudopotential mu*, transition temperature T-C, isotope effect exponent alpha and effective interaction strength NOV of ten binary CuCZr100-C (C = 0.25, 0.30, 0.33, 0.35, 0.40, 0.45, 0.50, 0.55, 0.57 and 0.60) metallic glasses have been reported using Ashcroft's empty core ( EMC) model potential. Five local field correction functions proposed by Hartree ( H), Taylor (T), Ichimaru-Utsumi (IU), Farid et al (F) and Sarkar et al (S) are used in the present investigation to study the screening influence on the aforesaid properties. It is observed that the electron -phonon coupling strength . and the transition temperature TC are quite sensitive to the selection of the local field correction functions, whereas the Coulomb pseudopotential mu*, isotope effect exponent a and effective interaction strength NOV show weak dependences on the local field correction functions. The TC obtained from the H-local field correction function is found to be in qualitative agreement with available theoretical or experimental data and shows an almost linear nature with the concentration C of the element Cu. A linear TC equation is proposed by fitting the present outcomes for the H-local field correction function, which is in conformity with other results for the experimental data. Also, the present results are found to be in qualitative agreement with other such data earlier reported, which confirms the superconducting phase in the metallic glasses.
10.1088-0953-8984-15-32-314	-1		In the equilibrium immiscible Cu-V system, interesting structural evolution was observed in the Cu-V multilayers upon 200 keV xenon ion beam mixing at 77 K. In the Cu30V70 sample, a unique amorphous phase was formed. In the Cu74V26 sample, an amorphous phase was partially formed and it transformed, after an over-irradiation dose, into I mixture of fcc and bcc solid solutions. The lattice constants of the fcc and bcc solid solutions were determined to be much larger than those of Cu and V, respectively, and can probably be attributed to a strong repulsive interaction between the Cu and V atoms. The observed structural evolution was discussed in terms of a thermodynamic calculation based on Miedema's theory and in terms of atomic collision triggered by ion irradiation.
10.1088-0953-8984-15-43-017	9	magnetic; magnetization; magnetoresistance; temperature; superparamagnetic; annealing; gmr; field; magnetic properties; ferromagnetic; granular; samples; magnetic field; melt-spun; particles	Transport and low-frequency optical reflection measurements (180380 GHz) are reported for the quasi-three-dimensional conducting alloy Cu[(2,5(CH3)(2)-DCNQI)(0.70)(2,5(CD3)(2)-DCNQI)(0.30)](2) between room temperature and 35 K. The optical properties of the system are strongly anisotropic. It is metallic down to 60 K where a Mott-Peierls phase transition occurs. While the transverse conductivity remains practically unchanged, the longitudinal conductivity abruptly drops at the phase transition. Comparing our latest results with previous dc data and measurements of the microwave conductivity also reported here, we find indications of an ageing effect in these samples.
10.1088-0953-8984-16-29-016	-1		The lattice constants and cohesive energies of some possible metastable Cu-W compounds are obtained by ab initio calculation and the formation of a metastable phase at Cu75W25 is predicted for the equilibrium immiscible Cu-W system. The prediction is in agreement with the fact that a metastable hcp phase was indeed observed in the Cu75W25 multilayer films upon ion beam mixing. Furthermore, some of the ab initio calculated properties are used in deriving an n-body Cu-W potential under the embedded atom method. The constructed Cu-W potential is then used to predict the phase stability of the metastable Cu-W phases over the entire composition and the prediction is also supported by some experimental observations.
10.1088-0953-8984-17-26-019	4	transformation; martensite; martensitic; phase; shape; beta; memory; shape memory; temperature; temperatures; martensitic transformation; gamma; transformation temperatures; effect; thermal	The decomposition of the metastable beta(3) phase and its influence on the martensitic transformation (MT) has been analysed in a Cu-14.37Al-4.2Ni (wt%) shape memory alloy processed by powder metallurgy by differential scanning calorimetry, resonant ultrasound spectroscopy and in situ neutron powder diffraction. The pro-eutectoid gamma(1) precipitation, the L2(1) to B2 disordering process and the eutectoid decomposition have been observed during heating, followed by its subsequent dissolution at higher temperatures. The gamma(1) precipitation limits high-temperature applications. The evolution of the kind of induced martensite, hysteresis and transformation temperatures has been analysed during the precipitation of the gamma(1) phase. The elastic stresses stored during quenching and the ordering degree play an important role in the MT evolution below 300 degrees C. At higher temperatures, the gamma(1) precipitation process induces an increase of the MT transformation temperatures and hysteresis.
10.1088-0953-8984-18-37-L03	-1		The structural transformation and disordered atomic packing of metallic glasses in a selected immiscible system at equilibrium, i.e. the Cu-Nb system characterized by a positive heat of formation, are studied using ion beam mixing far from equilibrium. The experimental results indicate that the Cu-Nb metallic glasses could be formed in a composition range from 30 to 85 at% of Nb and that the Cu-Nb metallic glasses are formed through two different structural phase transition routes, i.e. from the Nb-based body centred cubic and face centred cubic solid solutions, in which the two distinct predominant atomic packings have icosahedral and icositetrahedral orderings, respectively, revealed by the respective diffraction patterns. These observations not only help in formulating a general atomic structural spectrum for the binary metallic glasses, but also suggest an important concept of structural heredity: that the crystalline structure of the constituent metals plays a decisive role in determining the atomic structure of the resultant metallic glasses.
10.1088-0953-8984-19-3-032201	-1		Our notions of the phase stability of compounds rest to a large extent on the experimentally assessed phase diagrams. Long ago, it was assumed that in the Cu-Pd system for x(Pd) <= 25% there are at least two phases at high temperature (L1(2) and a L1(2)-based superstructure), which evolve into a single L1(2)-ordered phase at low temperature. By constructing a first-principles Hamiltonian, we predict a yet undiscovered Cu(7)Pd ground state at x(Pd) = 12.5% (referred to as S1 below) and an L1(2)-like Cu(9)Pd(3) superstructure at 25% (referred to as S2). We find that in the low-temperature regime, a single L1(2) phase cannot be stable, even with the addition of anti-sites. Instead we find that an S2-phase with S1-like ordering tendency will form. Previous short-range order diffraction data are quantitatively consistent with these new predictions.
10.1088-0953-8984-23-40-405404	-1		We report the lower stability temperatures, T-beta, of the body centred cubic (bcc) beta phase for several alloys along the line of compositions Cu0.76-0.5x-Zn-x-Al0.24-0.5x, corresponding to a constant electron to atom ratio e/a = 1.48. The results have been obtained by means of differential scanning calorimetry measurements at various heating rates. The influence of atomic ordering on the stability of the bcc structure was evaluated using a mixed approach involving Monte Carlo simulations and the cluster variation method. It was found that the chemical short- and long-range ordering contributes to the free energy of the alloy by an amount of around 200k(B).
10.1088-0953-8984-25-33-335402	4	transformation; martensite; martensitic; phase; shape; beta; memory; shape memory; temperature; temperatures; martensitic transformation; gamma; transformation temperatures; effect; thermal	The time evolution of the physical properties of martensite during martensite ageing is traditionally explained by the symmetry-conforming short-range order (SC-SRO) principle, which requires the spatial configuration of crystal defects to follow the symmetry change of the host lattice. In the present study, we show that the volume change of the host lattice also contributes to the ageing effects in Cu-Al-Ni shape memory alloy besides the symmetry change. To substantiate this statement the gradual increase of the storage modulus with time at constant temperature was measured by dynamic mechanical analysis (DMA) and the experimental results were quantitatively described in the framework of the symmetry-conforming Landau theory of martensitic transformations in a crystal with defects. The comparison of experimental and theoretical results confirmed that the time dependence of the storage modulus is caused by two different physical mechanisms. Evaluations showing that the first mechanism is driven by the spontaneous symmetry change and the second mechanism is caused by the volume change after the martensitic transformation was carried out.
10.1088-0953-8984-26-12-125401	4	transformation; martensite; martensitic; phase; shape; beta; memory; shape memory; temperature; temperatures; martensitic transformation; gamma; transformation temperatures; effect; thermal	The existence of temporal correlations during the intermittent dynamics of a thermally driven structural phase transition is studied in a Cu-Zn-Al alloy. The sequence of avalanches is observed by means of two techniques: acoustic emission and high sensitivity calorimetry. Both methods reveal the existence of event clustering in a way that is equivalent to the Omori correlations between aftershocks in earthquakes as are commonly used in seismology.
10.1088-0960-1317-25-3-035023	-1		Microcantilevers coupled with combinatorial deposition were used to characterize the Young's modulus, residual stress and fracture strength of Cu-Sn-In thin films over a broad range of compositions. Measurement inaccuracies due to cantilever non-idealities were corrected using finite element simulations and deflection measurements at multiple locations. eta-phase with a composition Cu53Sn25In22 was discovered to have the highest fracture strength and therefore has potential in thin film solder bonding applications. This study provides a database for the mechanical properties of a wide range of Cu-Sn-In alloys. Moreover, the techniques developed in this study provide a highly efficient approach to finding an intermetallic compound composition with the most desired mechanical properties.
10.1088-0964-1726-18-2-025014	-1		One of the principal limitations in the use of shape memory alloys is certainly fatigue behaviour. Initially, the mechanical behaviour of polycrystals evolves during cycling and then rupture occurs after a relatively small number of cycles, in particular for deformation higher than a few per cent. If one replaces the polycrystal by a single crystal, one notices an important increase in the fatigue lifespan, mainly for high deformation (Siredey et al 2005 Mater. Sci. Eng. A 396 296-301). The aim of this study is to analyse the role of three parameters influencing the lifespan in mechanical fatigue. The first one relates to the atmosphere in which the test is carried out. No notable influence was found. However, for samples having spent 44 000 h in air, one notes a lifespan reduction for those tested in the presence of air, whereas it is normal for those tested under argon. In the second part, the effect of the surface state will be discussed. As already presented in Siredey et al (2005 Mater. Sci. Eng. A 396 296-301), surface roughness influences lifespan, especially for low imposed strain. However, for higher strain this effect is much less important. On the surface, striations due to martensitic transformations appear during cycling. However, the damage inside these striations seems not to be correlated to rupture. The third parameter relates to crystalline quality of the single crystal. It was studied with a hard x-ray diffractometer using a transposition at high energy of the Guinier-Tennevin method. Crystalline quality is found to play a crucial role in the lifespan in fatigue. The presence of sub-grains disoriented by about 1 degrees and mosaicity can reduce the lifespan by a factor up to 10.
10.1088-0964-1726-22-2-025025	3	sma; shape; shape memory; memory; smas; superelastic; bars; damping; cu-al-mn; mechanical; bending; applications; numerical; sma bars; material	Experimental and numerical works are reported to assess the cyclic response of concrete beams reinforced with superelastic alloy (SEA) bars. The feasibility of newly developed Cu-Al-Mn SEA bars, characterized by large recovery strain, low material cost and high machinability, is examined as partial replacements for conventional steel bars, in order to reduce residual cracks in structures during and after intense earthquakes. Four-point reverse cyclic bending tests were done on one-third scale concrete beams comprising three different types of specimens-conventional steel reinforced concrete, SEA reinforced concrete and SEA reinforced concrete (RC) with pre-tensioning. The results showed that SEA reinforced concrete beams demonstrated strong recentering capability and significant enhancement in crack recovery capacity, in comparison to steel reinforced beams. Furthermore, corresponding finite element models were generated to simulate the experimental observations. Both the experimental observations and finite element computations illustrated the superiority of SEA bars to conventional steel bars in providing RC beam specimens with recentering and crack recovery capabilities.
10.1088-0965-0393-14-1-001	-1		The current paper presents a comparison of the influence over texture development of different heterogeneity levels of deformation. A viscoplastic self-consistent (VPSC) micromechanical model is coupled with a finite element method (FEM) to simulate wire drawing texture development in a two-phase Cu-Fe material. VPSC models are capable of simulating grain-to-grain heterogeneity, and FEM models can accomplish the task of simulating the macroscopic variation of velocity gradient due to geometrical constraints during wire drawing. Intra-grain heterogeneities are empirically built in the VPSC model by enforcing a common spin between closest neighbour grains. The results are contrasted and validated by neutron diffraction experimental textures. Different levels of heterogeneity are simulated, and the results are assessed and compared against Taylor based simulations. The 'curling' problem is also addressed by allowing the grains to interact through the co-spin model and the ellipsoid axes orientations to evolve independently.
10.1088-0965-0393-18-5-055006	7	irradiation; shear; grain; ta; deformation; size; radiation; voids; nanocrystalline; simulations; similar; void; temperature; irradiated; boundaries	The formation of shear bands during plastic deformation of Cu0.50Zr0.50 and Mg0.85Cu0.15 metallic glasses is studied using atomic-scale computer simulations. The atomic interactions are described using realistic many-body potentials within the effective medium theory, and are compared with similar simulations using a Lennard-Jones description of the material. The metallic glasses are deformed both in simple shear and in a simulated nanoindentation experiment. Plastic shear localizes into shear bands with a width of approximately 5 nm in CuZr and 8 nm in MgCu. In simple shear, the shear band formation is very clear, whereas only incipient shear bands are seen in nanoindentation. The shear band formation during nanoindentation is sensitive to the indentation velocity, indenter radius and the cooling rate during the formation of the metallic glass. For comparison, a similar nanoindentation simulation was made with a nanocrystalline sample, showing how the presence of a polycrystalline structure leads to a different and more spatially distributed deformation pattern, where dislocation avalanches play an important role.
10.1088-0965-0393-21-2-025005	13	clusters; atomic; glass; atoms; composition; dynamics; metallic; icosahedral; glasses; simulations; molecular; cu-zr; molecular dynamics; metallic glasses; structural	An embedded atom method (EAM) interatomic potential is constructed to reproduce the main topological features of the experimental equilibrium phase diagram of the Cu-Nb system in both solid and liquid states. The potential is fitted to composition-dependent enthalpies of mixing for bcc and fcc random solid solutions obtained from first-principles calculations at 0 K. Compared with two other EAM Cu-Nb potentials in the literature, the phase diagram of the current potential shows better agreement with the experimental phase diagram. Our potential predicts that the Cu-Nb liquid phase at equilibrium is compositionally patterned over lengths of about 2.3 nm. The newly constructed potential may be used to study the effect of liquid thermodynamics and structure on properties of binary systems, such as radiation-induced mixing.
10.1088-1361-6463-aa95b3	2	corrosion; surface; film; electrochemical; films; spectroscopy; layer; current; solution; potential; resistance; composition; x-ray; ions; showed	p-type transparent conducting Cu alloyed ZnS thin films from CuxZn1-xS targets (x = 0.1, 0.2, 0.3, 0.4, and 0.5) were deposited on glass substrates via radio frequency sputtering. x-ray diffraction and TEM-SAED analysis show that all the films have sphalerite ZnS as the majority crystalline phase. In addition, films with 30% and 40% Cu show the presence of increasing amounts of crystalline Cu2S phase. Conductivity values. 400 S cm(-1) were obtained for the films having 30% and 40% Cu, with the maximum conductivity of 752 S cm(-1) obtained for the film with 40% Cu. Temperature dependent electrical transport measurements indicate metallic as well as degenerate hole conductivity in the deposited films. The reflection-corrected transmittance of this Cu alloyed ZnS (40% Cu) film was determined to be. 75% at 550 nm. The transparent conductor figure of merit (Phi(TC)) of the Cu alloyed ZnS (40% Cu), calculated with the average value of transmittance between 1.5 to 2.5 eV, was approximate to 276 mu S.
10.1088-1361-6463-aaac1a	9	magnetic; magnetization; magnetoresistance; temperature; superparamagnetic; annealing; gmr; field; magnetic properties; ferromagnetic; granular; samples; magnetic field; melt-spun; particles	We have investigated the influence of magnetic interactions on the microstructural evolution of nano-scale granular precipitates formed spontaneously in an annealed Cu-20at% Ni-5at% Co alloy and the associated changes of magnetic properties. The techniques used included transmission electron microscopy, superconducting quantum interference device (SQUID) magnetometry, magneto-thermogravimetry (MTG), and first-principles calculations based on the method of Koster-Korringa-Rostker with the coherent potential approximation. Our work has revealed that the nano-scale spherical and cubic precipitates which formed on annealing at 873 K and 973 K comprise mainly cobalt and nickel with a small amount of copper, and are arranged in the < 100 > direction of the copper matrix. The SQUID and MTG measurements suggest that magnetic properties such as coercivity and Curie temperature are closely correlated with the microstructure. The combination of results suggests that magnetic interactions between precipitates during annealing can explain consistently the observed precipitation phenomena.
10.1088-1361-6463-ae04f6	14	strength; properties; conductivity; electrical; mechanical; cu-; grain; mpa; electrical conductivity; aging; precipitation; phase; mechanical properties; tensile; phases	This study investigates the effects of high-frequency alternating current (AC) treatment on the microstructural evolution and electrical properties of electron-beam-deposited Cu thin films. After 60 min of AC treatment at a frequency of 500 kHz, the resistivity of the Cu thin films decreased to 97.9%, 95.6%, and 94.1% of their initial values at current densities of 30, 40, and 50 kA mm(-2), respectively. COMSOL simulations confirmed that the maximum temperature rise did not exceed 50 degrees C, demonstrating that the process was dominated by the applied current rather than thermal effects. Quasi-in-situ electron backscatter diffraction results revealed that, under the 50 kA mm(-2) condition, AC treatment increase the average grain size from 0.263 mu m to 0.432 mu m and reduced kernel average misorientation from 0.595 to 0.540. Unlike conventional thermal annealing, which relies on random atomic diffusion, AC treatment imparts a directional driving force that enhances the <101> texture in the current direction. These findings demonstrate that high-frequency AC treatment is an efficient, non-thermal processing method that can enhance crystallinity and electrical conductivity of Cu films under near-room-temperature conditions (below 50 degrees C). In addition, this approach offers controllable regulation of grain orientation, indicating strong potential for applications in semiconductor interconnects, microelectronics, and advanced thin-film technologies.
10.1088-1361-651X-aabce4	13	clusters; atomic; glass; atoms; composition; dynamics; metallic; icosahedral; glasses; simulations; molecular; cu-zr; molecular dynamics; metallic glasses; structural	We present an embedded atom method (EAM) potential for the binary Cu-Au system. The unary phases are described by two well-tested unary EAM potentials for Cu and Au. We fitted the interaction between Cu and Au to experimental properties of the binary intermetallic phases Cu3Au, CuAu and CuAu3. Particular attention has been paid to reproducing stacking fault energies in order to obtain a potential suitable for studying deformation in this binary system. The resulting energies, lattice constant, elastic properties and melting points are in good agreement with available experimental data. We use nested sampling to show that our potential reproduces the phase boundaries between intermetallic phases and the disordered face-centered cubic solid solution. We benchmark our potential against four popular Cu-Au EAM parameterizations and density-functional theory calculations.
10.1088-1361-651X-aba737	-1		Grain boundary (GB) migration and Zener pinning, i.e. retardment of migrating GBs by second-phase particles, in a nanocrystalline Cu-Ag alloy have been investigated via molecular dynamics simulation. Among 86 GBs of different rotation axes and misorientation angles, about half of the GBs either did not move for an obvious distance within limited simulation time or underwent unsteady migration, and the other GBs exhibited steady migration. For the motionless and unsteady-migration GBs, boundary faceting was frequently observed. In particular, as found in experiments, all low angle GBs and several high angle GBs became faceted. For the steady-migration GBs, rotation-axis and misorientation dependences of GB energy, GB mobility and particle pinning effects have been systematically revealed. It is found that both the energy and mobility of low angle GBs were generally lower than those of high angle GBs, GBs of distinct rotation axes differed in mobility by as large as three orders of magnitude, and the maximum pinning force always agreed well with the theoretical prediction proposed by Ashbyet al[1]. Moreover, pinning efficiency obtained via comparisons between boundary migration with and without the pinning indicates that the efficiency is not related to the GB mobility or the maximum pinning force and a nanosized second phase particle seems to have a limited effect on retarding GB motion in very fine nanograins.
10.1088-1361-6528-aab19a	7	irradiation; shear; grain; ta; deformation; size; radiation; voids; nanocrystalline; simulations; similar; void; temperature; irradiated; boundaries	In order to achieve desired mechanical properties of alloys by manipulating grain boundaries (GBs) via solute decoration, it is of great significance to understand the underlying mechanisms of microstructural evolution and plastic deformation. In this work, nanocrystalline (NC) Cu-W alloyed films with W concentrations spanning from 0 to 40 at% were prepared by using magnetron sputtering. Thermal stability (within the temperature range of 200 degrees C-600 degrees C) and hardness of the films were investigated by using the x-ray diffraction, transmission electron microscope (TEM) and nanoindentation, respectively. The NC pure Cu film exhibited substantial grain growth upon all annealing temperatures. The Cu-W alloyed films, however, displayed distinct microstructural evolution that depended not only on the W concentration but also on the annealing temperature. At a low temperature of 200 degrees C, all the Cu-W alloyed films were highly stable, with unconspicuous change in grain sizes. At high temperatures of 400 degrees C and 600 degrees C, the microstructural evolution was greatly controlled by the W concentrations. The Cu-W films with low W concentration manifested abnormal grain growth (AGG), while the ones with high W concentrations showed phase separation. TEM observations unveiled that the AGG in the Cu-W alloyed thin films was rationalized by GB migration. Nanoindentation results showed that, although the hardness of both the as-deposited and annealed Cu-W alloyed thin films monotonically increased with W concentrations, a transition from annealing hardening to annealing softening was interestingly observed at the critical W addition of similar to 25 at%. It was further revealed that an enhanced GB segregation associated with detwinning was responsible for the annealing hardening, while a reduced solid solution hardening for the annealing softening.
10.1088-1361-665X-aa5f0b	3	sma; shape; shape memory; memory; smas; superelastic; bars; damping; cu-al-mn; mechanical; bending; applications; numerical; sma bars; material	This paper presents an experimental and numerical study showing that single crystal shape memory alloy (SMA) Cu-based endodontic instruments can lead to equivalent mechanical performances compared to NiTi-based instruments besides their interesting biological properties. Following a previous finite element analysis (FEA) of single crystal CuAlBe endodontic instruments (Vincent et al 2015 J. Mater. Eng. Perform. 24 4128-39), prototypes with the determined geometrical parameters were machined and experimentally characterized in continuous rotation during a penetration/rem oval (P/R) protocol in artificial canals. The obtained mechanical responses were compared to responses of NiTi endodontic files in the same conditions. In addition, FEA was conducted and compared with the experimental results to validate the adopted modeling and to evaluate the local quantities inside the instrument as the stress state and the distribution of volume fraction of martensite. The obtained results highlight that single crystal CuAlBe SMA prototypes show equivalent mechanical responses to its NiTi homologous prototypes in the same P/R experimental conditions.
10.1088-1361-665X-ab0b73	-1		Metals are usually difficult to fabricate bulk materials with a large grain size over cm-scale only through heat treatment with neither directional solidification nor macroscopic deformation. This paper reports a novel method to obtain large grains and single crystals over cm-scale only through simply annealing polycrystalline cast Cu-Al-Mn-V shape memory alloys. The results show that the abnormal grain growth (AGG) directly occurs when cast alloys are annealed at 1173 K, and ultra-large grains and single crystals are obtained after quenching. The AGG results from unique microstructure of cast Cu-Al-Mn-V alloys. All cast alloys consist of L2(1-)Cu(2)AlMn parent and completely coherent bcc A2(V) nanoparticles due to bcc phase separation. The results further show that the dissolution of A2(V) nanoparticles into the matrix during annealing results in a continuous misorientation gradient within the matrix grains. It may provide the driving force for the rapid migration of grain boundaries, leading to the AGG. Furthermore, the single crystals close to [901] exhibit good superelasticity. Cu-13.7Al-8.6Mn-1.4 V single crystal shows the largest full superelasticity of 7.0%, and Cu-13.2Al-9.8Mn-0.7 V single crystal exhibits the largest superelastic strain of 5.4%.
10.1088-1402-4896-ac112d	13	clusters; atomic; glass; atoms; composition; dynamics; metallic; icosahedral; glasses; simulations; molecular; cu-zr; molecular dynamics; metallic glasses; structural	Reported here are expressions temperature dependence under pressure effects for the mean square displacement, the mean square relative displacement, the correlation displacement function of atoms, and the ratio of the relationship between the quantities due to anharmonicity under pressure effects in extended x-ray absorption fine structure spectra. The expressions are determined using the anharmonic correlated Debye model and the anharmonic Debye model. Complicated calculations due to the many-particle effects and anharmonic properties are replaced by a calculation based on the effective anharmonic potential, including the interaction of absorbing and scattering atoms with their nearest-neighbour atoms. Based on the Debye-Waller factor, the difference between the mean square relative displacement and mean square displacement is analyzed, and their ratios are calculated. This work is applied to face-centered cubic crystals and their alloys. Numerical results for copper (Cu-Cu), silver (Ag-Ag) crystals and copper-silver alloys CuxAg1-x agree with experimental values and other studies.
10.1088-1402-4896-ad6fdd	-1		The Cu-Cr-Zr copper alloy is known for its outstanding electrical conductivity and fatigue strength . However, the corrosion behaviour of the copper alloy should also be taken into account when adopting it in industrial applications, especially in the marine environments. This research aims to fabricate Cu alloy coupons using the Laser Powder Bed Fusion (LPBF) technique and subsequently test their corrosive performance in simulated seawater. This research confirms that the Cu5Zr precipitate formation during the LPBF process and the Cu2O passive layer formation were the main reason for the enhanced corrosive behavior of the LPBFed copper alloy. The OM (Optical Microscope), FESEM (Field Emission Scanning Electron Microscope) images supported in evaluating melt pool formations and irregularities, and also confirmed the polycrystalline structure. The diffraction pattern from the TEM (Transmission Electron Microscope) analysis confirmed the formation of Cu5Zr precipitate and grain size distribution, while their orientations were obtained from the EBSD (Electron Based Scattered Diffraction) EBSD analysis. Micro hardness was executed on the scanning and building directions, and it was found that the building direction possessed higher hardness of 54 HV0.3 which was 5% higher than in the scanning direction. This significant fluctuation in the hardness value is due to the closely packed equiaxed and columnar grains along the outer and inner regions of the melt pools. Potentio-dynamic polarization (PD) and electrochemical impedance spectroscopy (EIS) tests were performed on the printed copper alloy parts for various immersion periods of 0, 9, 18 and 38 h . Further, the XRD (x-ray Diffraction) analysis was performed on the corroded surface and it confirmed the Cu2O passive layer and the occurrence of Cu5Zr precipitate. The occurrence of Cu5Zr precipitates and Cu2O passive layer formation helped attain the maximum polarization resistance of 2033.8 ohm and minimum current density of 5.928 x 10-6 A cm-2 with minimum surface roughness of 3.447 mu m.
10.1088-1402-4896-ada2bd	-1		Cu-based materials consisting of immiscible elements have been paid much attention due to their high strength and high conductivity. The amorphous layers between Cu and strengthening phases formed through severe deformation play a crucial role in the improvement of properties. In this study, structure evolution, thermal stability of Cu100-xTax (x = 10, 30, 50, and 70 at%) amorphous alloys and diffusion behaviors of alloys were studied by ab initio molecular dynamics (AIMD) simulations. With the Ta concentration rising, the number increase of Cu-Ta and Ta-Ta bonds results in the increase of volume for Cu-Ta amorphous alloys. Ta tends to be soluble in Cu clusters for Cu-rich amorphous alloys while Cu tends to be soluble in Ta clusters for relatively Ta-rich ones. According to energy evolution, the thermal stability of amorphous alloys decreases and then increases as Ta concentration increases. Compared with Cu element, the diffusion of Ta is significantly limited. The differences in thermal stability between Cu-Ta amorphous alloys and diffusion of Cu and Ta elements result in the formation of Ta-rich amorphous alloys after non-equilibrium fabricating. These results could substantively contribute to the development of Cu-based materials and understanding of the interface characteristic of immiscible alloys.
10.1088-1402-4896-adf780	-1		Interfacial bonding performance optimization of copper-steel bimetallic composites is a key challenge to improve their engineering service performance. This study focuses on the effect of Sn on Cu/Fe interfacial diffusion, and reveals the correlation law between Sn content (0%-15%) and interface bonding performance. The results show that the introduction of Sn promotes the Cu-Fe interdiffusion, increasing the diffusion coefficient of Cu and Fe, the thickness of the interface transition zone increases from 1.41 mu m to 6.54 mu m, and the proportion of the copper-rich area increases to 92.7%. The proportion of (alpha+delta) eutectoid phase increases with the increase of Sn content. XRD results show that the diffraction intensity of delta phase at the interface is positively correlated with Sn content. The evolution of phase compositions in copper layer promotes the change of fracture mode from toughness to brittleness. This study clarifies the interface binding mechanism of alloying elements and provides theoretical guidance for composition design and property prediction of copper-steel composites.
10.1088-1674-1056-23-3-036101	-1		Molecular dynamics simulations are performed to investigate the influence of irradiation damage on the mechanical properties of copper. In the simulation, the energy of primary knocked-on atoms (PKAs) ranges from 1 to 10 keV, and the results indicate that the number of point defects (vacancies and interstitials) increases linearly with the PKA energy. We choose three kinds of simulation samples: un-irradiated and irradiated samples, and comparison samples. The un-irradiated samples are defect-free, while irradiation induces vacancies and interstitials in the irradiated samples. It is found that due to the presence of the irradiation-induced defects, the compressive Young modulus of the single-crystal Cu increases, while the tensile Young modulus decreases, and that both the tensile and compressive yield stresses experience a dramatic decrease. To analyze the effects of vacancies and interstitials independently, the mechanical properties of the comparison samples, which only contain randomly distributed vacancies, are investigated. The results indicate that the vacancies are responsible for the change of Young modulus, while the interstitials determine the yield strain.
10.1088-1674-1056-27-8-086302	-1		The structural parameters, the formation energies, and the elastic and thermodynamic properties of the (CuxNi1-x)(3)Sn phase with different structures are studied by the virtual crystal approximation (VCA) and super-cell (SC) methods. The lattice constants, formation energies, and elastic constants obtained by SC and VCA are generally consistent with each other. It can be inferred that the VCA method is suitable for (CuxNi1-x)(3)Sn ordered phase calculation. The calculated results show that the equilibrium structures of Cu3Sn and Ni3Sn are D0(a) and D0(19) respectively. (CuxNi1-x)(3)Sn D0(3) with various components are the metastable phase at temperature of 0 K, just as D0(22) and L1(2). With the temperature increase, the free energy of the D0(3) is lower than those of D0(22) and L1(2), and D0(22) and L1(2) eventually turn into D0(3) in the aging process. The (CuxNi1-x)(3)Sn D0(22) is first precipitated in a solid solution because its structure and cell volume are most similar to those of a solid solution matrix. The L1(2) and the D0(22) possess better mechanical stability than the D0(3). Also, they may play a more important role in the strengthening of Cu-Ni-Sn alloys. This study is valuable for further research on Cu-Ni-Sn alloys.
10.1088-1674-1056-abbbf6	-1		Atomistic simulations are carried out to investigate the nano-indentation of single crystal Cu and the sliding of the Cu-Zn alloy. As the contact zone is extended due to adhesive interaction between the contact atoms, the contact area on a nanoscale is redefined. A comparison of contact area and contact force between molecular dynamics (MD) and contact theory based on Greenwood-Williamson (GW) model is made. Lower roughness causes the adhesive interaction to weaken, showing the better consistency between the calculated results by MD and those from the theoretical model. The simulations of the sliding show that the substrate wear decreases with the mol% of Zn increasing, due to the fact that the diffusion movements of Zn atoms in substrate are blocked during the sliding because of the hexagonal close packed (hcp) structure of Zn.
10.1088-1674-1056-abfbd6	-1		We describe simulations of lubrication by a hexadecane molecular lubricating film during the shearing process of a Cu-Zn alloy performed using the atomistic method. The results indicate that with increasing Zn contents, the interface slip between the alloy wall and the lubricating film first decreases and then increases, according to variations of the radius distribution function (RDF), while the interface slip reaches its lowest value of 0.12 during the shearing of CuZn30 alloy. We also discuss the relationship between interface roughness and the lubricating film. During film lubrication, the interface's roughness effectively inhibits interfacial slip. For the convex contact model, the presence of the hexadecane lubricating film reduces the interfacial contact pressure from 11.9 GPa to 8.7 GPa and the friction coefficient from 0.81 to 0.52.
10.1088-1741-4326-aa6bb3	5	materials; thermal; heat; properties; material; welding; sintering; fusion; strength; laser; heat sink; thermal conductivity; mechanical; sink; manufacturing	Copper alloy has been considered as a divertor cooling tube or heat sink not only in the helical reactor FFHR-d1 but also in the tokamak DEMO reactor, because it has a high thermal conductivity. This work focused on applying an oxide dispersion strengthened copper alloy (ODS-Cu), GlidCop (R) (Cu-0.3 wt% Al2O3) as the divertor heat sink material of FFHR-d1. This alloy has superior high temperature yield strength exceeding 300 MPa at room temperature even after annealing up to similar to 1000 degrees C. The change in material properties of Pure-Cu, GlidCop (R) and CuCrZr by neutron irradiation are summarized in this paper. A primary dose limit is the radiation-induced hardening/softening (similar to 0.2 dpa/1-2 dpa) which has a temperature dependence. According to such an evaluation, the GlidCop (R) can be selected as the current best candidate material in the commercial base of the divertor heat sink, and its temperature should be maintained as close as possible to 300 degrees C during operation. Bonding between the W armour and the GlidCop (R) heat sink was successfully performed by using an improved brazing technique with BNi-6 (Ni-11% P) filler material. The bonding strength was measured by a three-point bending test and reached up to approximately 200 MPa. Surprisingly, several specimens showed an obvious yield point. This means that the BNi-6 brazing (bonding) layer caused relaxation of the applied stress. The small-scale divertor mock-up of the W/BNi-6/GlidCop (R) was successfully fabricated by using the improved brazing technique. The heat loading test was carried out by the electron beam device ACT2 in NIFS. The mock-up showed an excellent heat removal capability for use in the FFHR-d1 divertor.
10.1088-1741-4326-aa8a9b	-1		Tungsten and Cu alloys are currently proposed as reference candidate material for ITER and DEMO first wall and divertor. Tungsten is proposed for its high fusion temperature and CuCrZr alloys for their high thermal conductivity together with good mechanical properties. However its behaviour under the extreme irradiation conditions as expected in ITER or DEMO fusion reactors is still unknown. Due to the determinant role of H and He played in the material behaviour any irradiation experiment must take into account the amount of these gases produced during the irradiation in Fusion reactors with high-energy neutrons. DONES (DEMO oriented neutron source) has been conceived as a simplified IFMIF (International Fusion Material Irradiation Facility) like plant to provide in a reduced time scale and with a reduced budget-both compared to IFMIF-the basic information on materials damage. The objective of DONES-IFMIF in its first stage will be to test structural materials under similar neutron irradiation nuclear fusion conditions as expected in fusion reactors. These tests will be carried out with specimens irradiated in the so called high flux test module (HFTM). The objective of this paper is to assess on the potential use of DONES to irradiate copper (Cu) alloys and tungsten (W) in the HFTM together with reduced activation ferritic martensitic steel like for example EUROFER (9%-Cr-steel). The presence of Cu alloys or W specimens may have an effect in the irradiation parameters of the EUROFER samples placed also in the HFTM and in the samples of the creep fatigue test module (CFTM). McDeLicious code is used for neutron transport calculations. Damage dose rate and H and He production are analysed in the different locations and compared with the irradiation conditions in first wall and divertor in fusion machines.
10.1088-2051-672X-ace467	-1		Surface nanocrystalline layers were prepared on Cu-8Cr alloy using ultrasonic shot peening (USSP) technique by controlling the pellet size and shot peening time. The tissue morphology, microstructure, surface hardness, surface strength and corrosion resistance of the generated surface nanolayers were systematically characterized using x-ray diffractometer (XRD), scanning electron microscope (SEM), and the corresponding test methods. The results showed that the USSP treatment did not change the surface phase of Cu-8Cr alloy, but only refined the surface grains into nanocrystals. The pellet size and shot peening time had a large effect on the surface properties of Cu-8Cr alloy. The best overall surface properties were obtained with a shot size of 2 mm and a shot time of 30 min The average grain size of the nano-layer is about 66 nm, the surface hardness is increased to 126.69 HV0.05, the tensile strength reached 417 MPa, and the corrosion resistance of the alloy is significantly enhanced. The USSP treatment provides a new method for the preparation of CuCr alloys with excellent surface properties.
10.1088-2051-672X-ad76c2	-1		Copper alloy bearings, gears, and fasteners have a significant impact on industrial sectors. However, due to the defect formation and void generation during the manufacturing of copper alloy parts using (Laser Powder Bed Fusion) LPBF technique, the wear resistance of the copper alloy was significantly affected. Hence, the prime novelty of the current research is enhancing wear resistance by analyzing the interaction of combined LPBF parameters. In order to decrease cavity forms and reduce the wear rate of the printed Cu alloy components, the important LPBF process parameters such as Scan Velocity (SV) of 550, 750, and 950 mm s-1, Laser Power (LP) of 460, 540, and 620 W, and Re-melting Range (RR) of 5, 25, and 45% were selected and studied. The results of the experimental investigation were supported by the use of Grey Relation Analysis (GRA). A comparative study was conducted with five distinct parameter combinations to investigate the relative influence of each parameter on the relative density, wear rate and elastic modulus. The research findings verify that the application of optimal SV of 750 mm s-1 and RR of 45% with maximum LP of 460 W resulted in the maximum relative density of 99.91%, minimal wear rate of 0.52 x 10-5 mm3/Nm, and maximum elastic modulus of 140.22 GPa.
10.1088-2051-672X-ad8a74	-1		Modified surface layers with refined grain size and high microhardness characteristics were prepared on Cu-Ti alloy using ultrasonic shot peening (USP) by controlling the shot diameter. The phase structure and organization morphology of the modified layer were analyzed using x-ray diffraction (XRD), optical microscopy (OM) and scanning electron microscope (SEM). The microhardness, wear resistance and corrosion resistance were systematically characterized. The results showed that the comprehensive surface properties of the sample was optimized at a shot diameter of 3.0 mm. The average grain size was refined to 12.4 nm under the high-frequency impact of steel balls. Owing to the grain refinement and work hardening, the surface microhardness, wear resistance and corrosion resistance of the sample was significantly improved. Among these, the surface microhardness of the sample was enhanced from 257.68 HV0.1 to 313.51 HV0.1, the volume wear rate was decreased from 0.3305 um(2) N-1 to 0.1707 um(2) N-1, and the self-corrosion current density was also decreased from 1.658 x e(-5) mA mu m(-2) to 4.053 x e(-6) mA mu m(-2). It is proved that USP is one of the effective methods for preparing Cu-Ti alloys with excellent surface properties.
10.1088-2053-1591-aa84a7	-1		Cu-Ni-graphite composites are intended for application in switch slide baseplate materials. The microstructure of the composites depends strongly on the ball milling time, and a suitable time can significantly improve the properties of the Cu-Ni-graphite composites. In this study, a two-step milling method was employed. The morphology evolution and microstructural features of the powder was characterized at different milling times. Afterwards, the Cu-Ni-graphite composites were prepared in the process of cold pressing, sintering, re-pressing and re-sintering as a function of the different milling times. Finally, both the microstructure and mechanical properties of the Cu-Ni-graphite composites are discussed. The results show that no new phase was generated during the milling process. The morphology evolution of the mixture of Cu/Ni powder changed from spherical-like to cubic-like, plate-like and flake-like with an increasing milling time. The microstructure of the composites consisted of a-phase and graphite. The boundary area and quantity of pores changed as the milling time increased. The relative density, hardness and flexural strength reached maximum values at 15 h of milling time.
10.1088-2053-1591-aa87f9	15	aging; strength; conductivity; electrical conductivity; electrical; mpa; treatment; strengthening; degrees; cu-; cold; precipitation; tensile strength; tensile; iacs	Cu-Ni-Si alloys with 90% Cu content and Ni to Si ratios of 5: 1 were fabricated by fusion casting, and severe plastic deformation of the Cu-Ni-Si alloy was carried out by multi-direction forging (MDF). The results showed that the as-cast and homogenized Cu-Ni-Si alloys consisted of three phases, namely the matrix phase a-Cu (Ni, Si), the reticular grain boundary phase Ni31Si12 and the precipitated phase Ni2Si. MDF significantly destroyed the net-shaped grain boundary phase, the Ni31Si12 phase and refined the grain size of the Cu matrix, and also resulted in the dissolving of Ni2Si precipitates into the Cu matrix. The effect of MDF on the conductivity of the solid solution Cu-Ni-Si alloy was very significant, with an average increase of 165.16%, and the hardness of the Cu-Ni-Si alloy also increased obviously.
10.1088-2053-1591-aa993f	-1		In this work, experiments were conducted to evaluate the evolution of microstructure and texture in a commercial Cu-2.77Ni-0.65Si-0.18Mg (wt%) alloy during processing by secondary cold rolling at room temperature. The influence of rolling reduction was investigated by electron backscatter diffraction. The results show that with the increase of secondary rolling reduction after formation of the solid solution, both the strength and elongation anisotropy of the Cu-Ni-Si-Mg alloy show an initial decrease followed by an increase. The anisotropy is weakest when the alloy is in its intermediate reduction state. Detailed measurements demonstrate that the anisotropy was largely affected by Brass and S texture. The shear bands contribute to second phase precipitation and lead to a decrease in the anisotropy degree. In addition, the Brass texture gradually increased by intense microscopic shear band formation.
10.1088-2053-1591-aa9f3c	2	corrosion; surface; film; electrochemical; films; spectroscopy; layer; current; solution; potential; resistance; composition; x-ray; ions; showed	The motivation of this study is to understand whether zinc-based alloy also has a passivation behaviour similar to zinc itself. Cu-Zn alloys were electrodeposited potentiostatically from a pyrophosphate medium on a carbon steel electrode and their corrosion behaviours were studied. Pt and carbon steel electrodes were used in order to examine the corrosion/passivation behaviour of bare Cu, bare Zn and Cu-Zn alloy coatings. The passivation behaviour of all brass-modified electrodes having Zn content between 10% and 100% was investigated. The growth potential affects the morphology and structure of crystals. The brass coatings are more porous than their pure components. The crystalline structure of Cu-Zn alloys can be obtained by changing the deposition potential. The zinc content in brass increases when the deposition voltage applied decreases. However, the growth potential and the ratio of zinc in brass do not affect the passivation behaviour of the resulting alloys. The coatings obtained by applying different growth potentials were immersed in tap water for 24 h to compare their corrosion behaviours with carbon steel having pitting formation.
10.1088-2053-1591-aaabc5	15	aging; strength; conductivity; electrical conductivity; electrical; mpa; treatment; strengthening; degrees; cu-; cold; precipitation; tensile strength; tensile; iacs	The crystallography and morphology of precipitate particles of Cu-Cr-Zr alloys with varying Zr contents were studied by transmission electron microscopy (TEM) after solution treatments at 950 degrees C for 1 h and aging treatments at 500 degrees C for different times ranged from 0.5 h to 24 h . The microhardness and electrical conductivity of Cu-Cr-Zr alloys after various aging process were tested. The results show that the microhardness and electrical conductivity rapidly increased at first, then the microhardness decreased slowly after reaching the peak, while the conductivity continues to increase. Nano-scaled precipitates exhibit two kinds of morphology (coffee bean and ellipse shaped). With increasing Zr content, the Zr-containing precipitation sequence of Cu-Cr-Zr alloys at peak-ageing is Heusler CrCu2Zr -> Cu5Zr -> Cu4Zr. The Heusler CrCu2Zr phase decomposed into fine and homogeneous Cr and Cu4Zr, resulting in improved alloy properties.
10.1088-2053-1591-aab8e8	13	clusters; atomic; glass; atoms; composition; dynamics; metallic; icosahedral; glasses; simulations; molecular; cu-zr; molecular dynamics; metallic glasses; structural	Using a first-principles calculation, correlation between the chemical order and nature property of Cu-centered CunZr13-n(n = 6, 7, 8, 9) icosahedral clusters is investigated. It is found that homogeneous atoms in shell of Cu-Zr icosahedral clusters with low binding energy and high chemical stability prefer to bond each other. In this case, the Cu-Cu interaction is demonstrated to play a key role in the formation of stable Cu-centered Cu-Zr icosahedral clusters. Compared with other metastable Cu-centered Cu-Zr icosahedrons, both of ionic bonding between core and shell Cu atoms and covalent bonding between shell and shell Cu atoms in high stable icosahedrons are strong. An analysis of electronic structures has revealed that this atomic segregation in low energy and high chemical hardness of stable Cu-Zr icosahedral configurations can be attributed to themselves low N(E-F ) at Femi level E-F to some extent. A further analysis of Mulliken's population shows these shell Cu atoms are all donees in the formation of Cu-Zr icosahedral cluster, different from the donation of core Cu atoms and shell Zr atoms, and this charge transfer direction does not change with chemical order parameter delta(CuZr) and chemical composition of Cu-centered Cu-Zr icosahedral clusters.
10.1088-2053-1591-aacc4a	-1		Since the grain size and microstrain amounts in the microstructure affects the final properties, studying the effect of annealing parameters on grain size and microstrain using experimental data and statistical models is important for designing strong metals. In this work, nanostructured Cu powder prepared by high-energy ball milling was annealed at various conditions. The effects of annealing time and temperature on the grain size and microstrain were investigated using response surface methodology. X-ray diffraction was conducted to measure the grain size and microstrain. In addition, scanning electron and transmission electron microscopies were used to characterize the produced powder. The results showed that the models were predicting the responses, accurately. The annealing temperature was the most effective parameter to minimize the microstrain as a result of concurrent existence of recovery, recrystallization, and grain growth . The developed models can be used for predicting grain size and microstrain, and therefore they can be accepted as an economical way to extract arbitrary information about grain growth kinetics of annealed Cu nanostructured powders.
10.1088-2053-1591-aacf1c	17	wear; composites; coating; friction; composite; coatings; surface; tribological; properties; wear resistance; resistance; powder; sliding; matrix; wear rate	The microstructures and the mechanical/electrical properties of graphene nanoplates-copper (GNPs-Cu; 0.4 wt%) composites and the composites doped by cobalt (GNPs: 0.4 wt%; Co: 2, 3, 4 wt%) have been researched, which have been prepared by mechanical alloying and spark plasma sintering (SPS) technology. It is found that GNPs disperse evenly in Cu matrix with the ball milling time of 6 h . The compressive strength and the hardness of GNPs-Cu are 601.88 MPa and 128 HV, respectively, which were increased by 3 times and 42.2% compared to pure Cu. And the IACS of the GNPs-Cu composites was 79%. The GNPs-Cu composites with 3 wt% Co (3 wt% Co-GNPs-Cu) also present excellent mechanical properties. The compressive strength and the hardness is 571.32 MPa and 145 HV, respectively, which is raised by 2.81 times and 61.1% compared to pure Cu. And the IACS of the 3 wt% Co-GNPs-Cu composites is 65%. In addition, based on the first principle calculation the mechanism of the effect of Co doping on the GNPs-Cu interface bonding has been studied. Our results provide experimental basis for the preparation of high strength and high conductivity Cu matrix composites, which can be widely used in many fields, such as high-strength magnetic field, heat exchange material, etc.
10.1088-2053-1591-aad9d3	-1		Through an EBSD analysis on the change characteristics of the microstructure of a spinning formed thin-walled Cu-Sn alloy cylinder which is annealed at 300 degrees C-600 degrees C for 2 h, it indicates that the grain size increases with the rise of annealing temperature and the size falls back at 400 degrees C. At 300 degrees C, the microstructure is mainly composed of deformed grains. With the progress of recrystallization, the deformed grains disappear first, and the number of substructures gradually reduces but always exists. In terms of the grain boundary, the subgrain boundaries gradually disappear and the Sigma 9 grain boundary at the secondary peak gradually transforms into the Sigma 3 grain boundary. At 300 degrees C, a {100}//Z(0) fiber texture appears, but the general orientation of the grain is random at other temperatures. The detection of mechanical properties found that the elongation of Cu-Sn alloy increasing from 14% to 65% gradually and the yield strength (YS) and tensile strength (TS) decreasing to 282 MPa and 352 MPa respectively.
10.1088-2053-1591-aadb10	-1		The effects of Y addition on the solidified microstructure, mechanical and electrical properties of Cu-1Cr-0.1Zr-xY (x = 0-0.1 wt%) alloys were investigated during the directional solidification process. The results show that the Cu-rich structures are the long cellular when the additions of Y are 0.02 wt% and 0.04 wt%. They are the short cellular when the addition of Y lower than 0.02 wt% and exceed 0.04 wt%. After the heat treatment process, the size of the coarse Cr phase changes from 500 nm (without Y) to 200 nm (0.06 wt%Y), and the dispersed Cr-rich precipitates become more with the addition of 0.06 wt% Y, which accounts for the increase in tensile strength and electrical conductivity of Cu-Cr-Zr-Y alloy. The Cu-1Cr-0.1Zr-0.06Y alloy possesses the best ultimate tensile strength (UTS), elongation and electrical conductivity which are 254.1 MPa, 48% and 84.59% IACS, respectively.
10.1088-2053-1591-aadfbe	-1		A two dimensional steady state laminar flow model was established using finite volume software to study the effects of rolling speed and melt pouring temperature on the bonding performance of a copper/aluminum composite plate manufactured using a cast-rolling process. The boundary conditions were optimized in two aspects by writing C language programs. Meanwhile, outlet temperature was measured by thermocouple in the experiment, the maximum error of the simulation and experiment was 2.8%, so the reliability of the simulation analysis was verified. The study found that semi-solid/solid contact time and rolling reduction percentage are the key factors affecting bonding, with pouring temperature and rolling speed changing which factor plays a leading role. The calculated results show that the optimal pouring temperature and casting speed are 963 K and 0.5 m min(-1), respectively. Processing under these conditions results in semi-solid/solid contact time of 2.2 s and rolling reduction of 40% based on simulation results, with experimental peeling strength of 86 N mm(-1). Optical images of surface morphology after peeling show that the failure mechanism of the Cu/Al composite plate is plastic and brittle fracture. This study provides guidance for optimizing cast-rolling processing parameters.
10.1088-2053-1591-aaf085	6	grain; deformation; strain; strength; dislocation; cu-; tensile; size; ecap; grain size; sfe; ductility; hardening; high; stress	Cu-Ti alloy, processed by multiaxial forging (MAF) at cryogenic temperature with a cumulative strain up to 1.64, was investigated for microstructure and mechanical properties. The deformed microstructures were analyzed using optical microscopy (OM), scanning electron microscopy (SEM), and transmission electron microscopy (TEM). The average grain size of 2 mu m was achieved in the deformed sample after 3 cycles of MAF. TEM studies indicated that the shear bands width of the deformed sample after 3 cycles reduced to 1 mu m. Tests for mechanical properties indicated an increase in tensile strength and hardness and it was found to be correlated with an increase in dislocation density and grain boundary strengthening mechanism. Ultimate tensile strength (UTS) of 390 MPa, 480 MPa, and 590 MPa was observed in MAF processed samples after 1, 2, and 3 cycles, respectively. Hardness increased from 65 HV (as-received) to 240 HV after 3 cycles of MAF. Fractography analysis showed that, with an increase in number of MAF cycles, dimple size reduced up to 1 cycle and percentage elongation increased after 2 cycles of MAF.
10.1088-2053-1591-aaf362	13	clusters; atomic; glass; atoms; composition; dynamics; metallic; icosahedral; glasses; simulations; molecular; cu-zr; molecular dynamics; metallic glasses; structural	In contrast to the generally accepted practice for searching metallic glassformers by trial-and-error quenching, we propose using density and coefficient of thermal expansion of as-cast polycrystalline alloys as indicators of the glass-forming ability. We study experimentally these characteristics for Cu100-xZrx alloys over the whole concentration range and a wide temperature range from room temperature up to 1120 K. In the concentration range of 35 < x < 55 at% corresponding to high glass-forming ability, strongly non-monotonous behavior of both quantities is observed. We reveal that location of the extrema on concentration dependencies of both the coefficient of thermal expansion and the density deviation from the additive law correlates with those for critical thickness of Cu-Zr amorphous alloys. We argue that correlation between glass-forming ability and anomalous behavior of thermal expansion is because as-cast polycrystalline samples of glass forming alloys possess highly distorted structure, which cause phonon anharmonicity. Our findings propose new express method to search metallic alloys with high glass-forming ability.
10.1088-2053-1591-aaf97e	-1		Alloys based on Cu-Zr-Al are known for their relative easiness in producing glassy structures. However, several important aspects related to the microstructure and the Glass Forming Ability (GFA) are still not well understood. Here, we present results referring to Molecular Dynamics simulations (MD) of rapidly quenched glassy Cu-Zr-Al of two compositions. GFAs were investigated, both experimentally and by MD simulations, using x-ray diffraction, High-Resolution Transmission Electron microscopy and Differential Scanning Calorimetry, while the structural evolution upon cooling was investigated by simulations using radial distribution functions, Voronoi tessellation analysis, and volume-temperature curves. Moreover, the viscosity evolution as well as the glass transition temperature and the fragility parameters were also estimated. Good agreement was found between the MD simulation results and the experimental data. It came out that the Zr-rich composition resulted in a 'stronger' metallic liquid than the Cu-rich composition. In addition, we found that the evolution of distorted into well shaped icosahedral clusters upon solidification, is a determining factor for the stability of the Zr-rich metallic glass. Moreover, we propose a new criterion based on a weighted average of the atomic radius ratio that has been found promising in adequately predicting glass forming abilities.
10.1088-2053-1591-aafaec	16	wear; composite; composites; powders; milling; particles; powder; wt; sliding; friction; hardness; matrix; mechanical; surface; properties	An attempt has been made to reinforce Copper (Cu) with low density material Fly Ash (FA) to form Cu-FA composite material through Powder Metallurgy (P/M) route. Samples of 3, 6 and 9 weight percentage of FA in Cu matrix were prepared. Scanning electron microscopy analysis was used to study the morphology of the composite materials. The x-ray diffraction analysis was used to characterize the elemental composition of composite powder. Energy-dispersive spectroscopy (EDS) mapping was used to find the homogeneous distribution of FA in Cu matrix. Mechanical behavior of the Cu-FA composite material was studied using Vickers hardness and compression test. The mechanism model for decrease in compressive strength of Cu-FA composite material was identified as boundary slip. The corrosion behavior of Cu-FA composite material in acidic (IN HCl) and in sea water media are studied. Electrochemical polarization test was used to carry out the corrosion studies on Cu-FA composite material in acidic media. The increase in Polarization Resistance (R-p = 68.6499 x 10(-4) Omega cm(2) in acidic media and R-p = 68.7532710(-4) Omega cm(2 )in sea water) of Cu-9FA evidences that increase in weight percentage reinforcement of FA in Cu matrix decreases the corrosion rate in both acidic and sea water media. The increase in charge transfer resistance (R-ct = 1142 Omega cm(2 ) ) of Electrochemical Impedance Spectroscopy (EIS) test authenticates that the corrosion resistance of Cu-9FA is healthier than pure Cu. It was observed that improved corrosion resistance and good mechanical properties are obtained for 9% FA reinforced Cu composite material.
10.1088-2053-1591-aafc17	8	hot; deformation; strain; strain rate; dynamic; hot deformation; recrystallization; dynamic recrystallization; flow; rate; flow stress; compression; constitutive; degrees; stress	The hot deformation behavior and microstructural evolution of Cu-0.21Cr-0.12Ag alloy made by the upward continuous casting were investigated by isothermal compression test, optical microscopy (OM), scanning electron microscopy(SEM), and electron backscatter diffraction(EBSD). The results show that the alloy undergoes complete dynamic recrystallization, and the recrystallized grains size decrease with strain rate increasing at 900 degrees C. Partial dynamic recrystallization occurs in the temperature range from 800 to 850 degrees C, fine recrystallized grains nucleate at grain boundaries, and the percentage of recrystallization decreases with decreasing deformation temperatures. Dynamic recrystallization does not occur at temperatures below 750 degrees C and the softening mechanism is dominated by dynamic recovery. The processing map was developed based on the dynamic material model theory, and it shows that the alloy is prone to instability at deformation temperatures below 730 degrees C.
10.1088-2053-1591-aafd6e	8	hot; deformation; strain; strain rate; dynamic; hot deformation; recrystallization; dynamic recrystallization; flow; rate; flow stress; compression; constitutive; degrees; stress	The flow and dynamic recrystallization (DRX) behaviour of the Cu-0.19Cr-0.1Ag alloy was systematically investigated by hot compression tests using a thermal simulation testing machine. The results showed that dynamic recovery and partial dynamic recrystallization occured at the strain rate of 10 s(-1) in the entire temperature range tested, and at strain rates varying between 0.01 s(-1) and 10 s(-1) below 850 degrees C. Complete dynamic recrystallization occured when the deformation temperature was higher than 900 degrees C. The maximum softening rate strain (epsilon*) and the variable Z were introduced in the DRX kinetic model developed for the Cu-0.19Cr-0.1Ag alloy, obtaining an Avrami constant of 1.88.
10.1088-2053-1591-ab0187	-1		Cu-Ni-Sn alloys are well known for their excellent properties, including excellent elasticity and high strength, which enable large potentials for applications in microelectronic industry and 3D printing for example. Preparation of the high quality spherical powders should meet the new requirements in these emerging fields. In this work, the mono-sized Cu-13Ni-17Sn (wt%) microspheres with controllable diameters ranging from 84.4 mu m to 212.0 mu m were prepared by pulsated orifice ejection method (POEM). Solidified Cu-Ni-Sn microspheres exhibit good sphericity and remarkably narrowed size distribution. The percentage of microspheres with sphericity of more than 0.9 is high up to 98.6%, and the average sphericity of microspheres is 0.989. The surface of Cu-Ni-Sn microspheres is smooth, and the interior contains no pores and impurities. Furthermore, the cooling rate of Cu-13Ni-17Sn microspheres was estimated in a Newton's cooling model. With decreasing particle diameter, the cooling rate of Cu-13Ni-17Sn microspheres increases gradually. When the particle diameter is less than 84.4 mu m, the cooling rate of microspheres exceeds 3.64 x 10(4) K s(-1). With increasing particle size, the secondary dendrite arm spacing increases gradually owing to the decrease of the sphere cooling rate.
10.1088-2053-1591-ab0764	-1		Combined multiaxial forging (MAF) and rolling was performed on Cu-3% Ti (wt%) alloy at room temperature with emphasis on microstructural evolution, improvement in mechanical properties, and corrosion resistance. Microstructural changes were confirmed from various characterization techniques, and co-related with mechanical properties. TEM analysis revealed high shear band density in the 3 pass MAF + 90% rolled sample appearing due to high strain. EBSD analysis revealed transformation to low angle grain boundaries from high angle grain boundaries. Maximum microhardness and UTS reached to 340 HV and 960 MPa, respectively in the processed samples. Significant grain refinement was observed in MAF processed Cu-3%Ti alloy, and after combined MAF + rolling, higher dislocation density and refinement of shear bands were observed. In addition, potentio-dynamic polarization test was used to study the corrosion behavior of the alloy. Scanning electron microscope (SEM) was used to analyze the corroded surface morphology.
10.1088-2053-1591-ab1fb9	8	hot; deformation; strain; strain rate; dynamic; hot deformation; recrystallization; dynamic recrystallization; flow; rate; flow stress; compression; constitutive; degrees; stress	Hot compression tests of Cu-Ni-Si alloy with high Ni and Si contents were carried out on Gleeble-3800 thermal simulator in the deformation temperature of 750 degrees C similar to 950 degrees C, strain rate of 0.01 similar to 10 s(-1) and deformation amount of 70%. Subsequently, constitutive equation based on Arrhenius-type constitutive model considering strain effect was established, and the average absolute relative error and correlation coefficient R were 7.34% and 0.991. Then, hot Processing map was obtained by combining the power dissipation and instability maps, and the suitable processing conditions could be predicted. Based on the results of these experimental and theoretical investigations on the hot deformation behavior of Cu-Ni-Si alloys, Multi-direction compression (MDC) was carried out at 860 degrees C and corresponding strain of single pass and accumulated 24 passes 0.4 and 9.6 respectively. The resulted microstructure consisted of fine matrix grains with a diameter of 3.02 mu m and well dispersed Ni31Si12 particles 0.62 mu m, suggesting that the results of thermal simulator and corresponding calculation were credible for guiding the thermo-mechanical processing parameters of Cu-Ni-Si alloys.
10.1088-2053-1591-ab2148	-1		In this study, a hyper-peritectic Cu-21 wt% Ce alloy was prepared by directional solidification method at various withdrawal rates of 100 mu m s(-1), 25 mu m s(-1), 6 mu m s(-1), 5 mu m s(-1), 4 mu m s(-1) and 2 mu m s(-1). The microstructure evolution was investigated by optical microscope. The phase constitutions were analysed by the x-ray diffraction, differential scanning calorimetry and transmission electron microscope. Further, the minimum spanning tree method was selected to investigate the spacing characters of dendritic arrays. The experimental results demonstrate that primary phase microstructure transforms from dendritic to island structure with decreasing the withdrawal rates, and the maximum volume fraction of the primary phase reached 45.16% at the withdrawal rate of 6 mu m s(-1). It was found that when reducing the withdrawal rate from 100 mu m s(-1) to 2 mu m s(-1), the primary dendrite spacing increased first and then decreased, with a maximum value of 144.64 mu m presenting at 6 mu m s(-1). The phase constitutions in the directional solidified samples were confirmed to be Cu6Ce, Cu4Ce and Cu4Ce + Cu2Ce eutectics. Moreover, the maximum compressive force was determined to be 10.3 kN and the maximum compressive strain was 3.73% respectively, corresponding to the maximum primary phase volume fraction at a withdrawal rate of 6 mu m s(-1). Directional solidification method has been proved to be an efficient way to improve the mechanical properties of hyperperitectic Cu-21%Ce alloy.
10.1088-2053-1591-ab2344	-1		Despite the constant stacking fault energy in Cu alloy, the addition of Mn promotes a structural evolution of copper-manganese (Cu-Mn) alloy that substantially differs from that of pure Cu during rolling. This advantage is leading to Cu-Mn alloy gradually replacing pure Cu as a sputtering target for fabricating integrated circuits because of its unique characteristic of a self-forming diffusion layer. Thus, the deformation texture evolution in a Cu-3 at%Mn alloy subjected to unidirectional rolling with different reductions was investigated. The spatial arrangement of the crystallographic texture and orientations of 22%, 36%, 50%, 61.3% and 70% rolled samples prepared in quasi in situ continuous rolling was analyzed using electron-backscatter diffraction (EBSD) combined with several deformation models, such as a modified materials-dependent Taylor model. Among all the deformations, several representative deformations-specifically, 50%, 77% and 95%-were selected to demonstrate macrotexture development by x-ray diffraction analysis. The results show that the dominant texture evolves from a Copper texture ({112} < 111 >) to a Brass texture ({110} < 112 >) accompanying deformation.
10.1088-2053-1591-ab2cff	16	wear; composite; composites; powders; milling; particles; powder; wt; sliding; friction; hardness; matrix; mechanical; surface; properties	A primary element of copper is dispersed with a secondary element (vanadium) by stir casting technique. This alloy is melted in a furnace and the percentage of Vanadium is added in Cu as 0%, 0.5%, 1.0%, 1.5% & 2% respectively. The metal matrix composite is characterised by x-ray diffraction, Optical micrograph, Energy Dispersive x-ray, Fourier Transform Infrared Spectroscopy and Fractography. It is found that by the addition of vanadium the grain size is getting reduced and the strength of the metal matrix increases. There is also a improvement in the hardness with the increase in vanadium content. Pin on-disc setup is used for wear study and it is found that there is an increase in wear resistance for the increase in vanadium content. The results observed from experiments that vanadium will act as a reliable reinforcement material for the enhancement of properties in copper matrix composites.
10.1088-2053-1591-ab2dd1	1	shape; memory; shape memory; damping; martensite; martensitic; damping capacity; transformation; capacity; strain; superelasticity; temperature; cu-al-mn; shape memory effect; effect	The relationship between damping capacity and up-quenching treatment is not clear in ductile Cu-Al-Mn shape memory alloys. To address this problem, effects of up-quenching time on evolutions of martensite amount, vacancy concentration, and their resulting damping capacity are investigated in a ductile Cu-16.59Al-10.55Mn alloy. The results show that the damping capacity rises at a lower rate than the amount of martensite does when the up-quenching time is below 15 min. Above 15 min, the damping capacity rises at a higher rate. The amount variation in the quenched-in vacancies results in the different relative increments between the martensite amount and damping capacity. Up-quenching for 180 min does not enhance the damping capacity at a low strain of 1 x 10(-4). The reason could be that the concentration of residual vacancies is still rather high .
10.1088-2053-1591-ab309d	2	corrosion; surface; film; electrochemical; films; spectroscopy; layer; current; solution; potential; resistance; composition; x-ray; ions; showed	Several research findings have been published on the influence of grain size control additives on the structure-property relationship and performance of Cu-Zn-Al Shape Memory Alloys. However, a wide knowledge gap still exists between the findings on the ordinary Cu-Zn-Al alloys and their shape memory counterparts. Herein lies a significant contribution that addresses this issue. Cu-Zn-Al and FeMn-modified Cu-Zn-Al alloys of preferred chemical compositions were developed by stir sand casting. The alloys were prepared for and subjected to metallographical and corrosion immersion tests in sulphate-containing, chloride-containing and designated physiological environments. Experimental results showed FeMn to be an effective inoculant for heterogeneous nucleation and crystal growth in Cu-Zn-Al alloys. Modified grains with different sizes and morphologies were observed. There also appeared to be a Hall-Petch kind of relationship between corrosion resistance and grain size of the FeMn-modified alloys in nearly all the corrosion media. Dezincification of the FeMn modified alloys was significantly facilitated with high Zn content and large grain size, notably in the sulphate-containing environment. Nonetheless, the dramatic difference in the corrosion behaviour of Cu-Zn-Al alloy and that of FeMn-modified Cu-Zn-Al alloys in the corrosion media only occurred at the initial stage of experiment. Thereafter, a stable corrosion behaviour was observed for the FeMn-modified alloys.
10.1088-2053-1591-ab30ea	2	corrosion; surface; film; electrochemical; films; spectroscopy; layer; current; solution; potential; resistance; composition; x-ray; ions; showed	The corrosion behavior of pure copper, aluminum, and Cu-Al laminated composite plates produced through semi-molten continuous casting and rolling exposed to salt fog were evaluated. The copper performed the best corrosion resistance, then the aluminum. At first a corrosion belt occurred along the interface next to the diffusion layer (intermetallic) at the preliminary stage on the aluminum side, the generated cracking corrosion products formed an another galvanic cell with surrounding aluminum matrix, where the aluminum as the anode, and then pits appeared on the aluminum near the interface and gradually expanded to larger and deeper holes, while some small holes appeared on the other areas of aluminum as the process went on, and then corrosion products exerted stress on the surface of grain to come up denudation. Finally, localized corrosion gradually developed to general corrosion. Besides, with the extension of corrosion time, the corrosion rate of Cu-Al firstly decreases, then increases and finally decreases again.
10.1088-2053-1591-ab319d	-1		Carbon Nanotube (CNT)/copper (Cu) based composites, with improved dispersibility of CNT in the Cu matrix and enhanced interfacial bonding between them, were fabricated successfully by twice in situ formation from powder preparation to sintering. Micron-sized CNT/Cu2O composite powders were obtained by in situ formation of electrostatic adsorption for the first time, followed low energy ball milling with Cu-1.0 wt%Ti alloy powder. After reduction, the as-received composite powder was sintered by hot pressing to form an in situ transition phase for the second time. Mechanical results show that the ultimate tensile strength (UTS) is about 361 MPa and elongation (EL) is about 30.8% of 0.4 wt%CNT/Cu-Ti composite, and the UTS is significantly increased compared with that of the matrix material (24.05%). Finally, strengthening mechanisms of the composite are considered. Enhancement of mechanical property is ascribed to a synergistic combination of the well-distributed CNT and in situ formed TiC nano transition phase.
10.1088-2053-1591-ab36f7	17	wear; composites; coating; friction; composite; coatings; surface; tribological; properties; wear resistance; resistance; powder; sliding; matrix; wear rate	The nano-La2O3 reinforced copper matrix composites were fabricated by a combination method of internal oxidation and spark plasma sintering (SPS) using Cu-La alloy powders. The microstructure, mechanical properties and electrical conductivity of the La2O3/Cu composites were investigated at different sintering temperatures. The results show that the grain size of the La2O3/Cu composites is a few microns due to the in situ generated La2O3 particles, which are predominantly distributed on the grain boundaries and effectively suppress migration of Cu grain boundary during the sintering process. The ultimate tensile strength, yield strength and hardness of La2O3/Cu composite sintered at 850 degrees C are 1.23 times, 2.2 times and 1.5 times that of Cu-La alloy, respectively. And the electrical conductivity is as high as 92.79% IACS. However, the elongation is significantly smaller than that of Cu-La alloy. Moreover, the strengthening mechanism and conductive mechanism of the material were studied based on the experimental results.
10.1088-2053-1591-ab3fd9	-1		Aporous Cu-Sn alloy with good pore formation and uniform distribution can be successfully prepared by filling sintering method with mixed powder of copper powder and tin powder as raw materials and K2CO3 as pore-forming agent under the conditions of ball milling for 20 min, blank forming pressure of 70 MPa, sintering at 900 degrees C and heat preservation for 1 h . By SEM, EDS, XRD and universal testing machine, the composition, particle size, microstructure and mechanical properties of porous copper alloy under different ball milling times were studied. The results show that the porosity of porous Cu-Sn alloy sample decreases with the increase of Sn powder content from 0% to 4%(mass fraction, the same below). The pore-forming agent K2CO3 does not react with Cu powder and Sn powder, which not only contributes to the formation of pores, but also is easy to be treated in later stage. The compressive resistance of porous copper alloy prepared was higher than that of porous pure copper. With the increase of Sn powder content, the curvature of porous copper alloy increases in the elastic stage, and the pressure value corresponding to plastic deformation increases, indicating that its ability to resist plastic deformation increases. However, the strain range has not changed significantly, indicating that the ductility has not changed much .
10.1088-2053-1591-ab43eb	17	wear; composites; coating; friction; composite; coatings; surface; tribological; properties; wear resistance; resistance; powder; sliding; matrix; wear rate	The single crystal alpha-Al2O3 fibre is an excellent reinforcement material for their excellent elastic modulus, high chemical and thermal stability. Copper matrix composites containing fixed amount alloys (Sn, Ni, Fe, etc) and different amounts of alumina whisker are prepared through mechanical alloying, hot-pressing and hot isostatic pressing. The results show that a solid solution structure is formed between the alloying elements and copper in which alumina whisker are uniformly distributed in the copper matrix. The compressive strength increases with the increase of Al2O3 whisker when the Al2O3 whisker content changes from 0.0 wt% to 1.5 wt%, and the maximum value reaches 288.26 MPa. The strengthening mechanism is fine grain strengthening and solid solution strengthening; besides, the dispersion mechanism and the mechanism of dislocation strengthening can also be exerted.
10.1088-2053-1591-ab43f7	4	transformation; martensite; martensitic; phase; shape; beta; memory; shape memory; temperature; temperatures; martensitic transformation; gamma; transformation temperatures; effect; thermal	The effect of Ti and rare earth elements (RE: Ce + La) addition on properties of Cu-14Al-4Ni shape memory alloy (SMA) with austenitic structure at room temperature was studied by implementing different characterization methods. The experimental results proved that combined adding of Ti and RE has significantly decreased the grain size and improved mechanical properties of the alloy. Microstructural observations showed that addition of Ti and RE caused secondary phases formation in the austenitic microstructure of the alloy at room temperature. The fracture strain was improved from 2% for Cu-Al-Ni to 2.9 and 3.5% for Cu-Al-Ni-Ti and Cu-Al-Ni-Ti-RE, respectively. Furthermore, the fracture mode altered from complete brittle intergranular fracture to a mixture of intergranular fracture and transgranular cleavage fracture with some localized dimples around particles of the secondary phases. The martensitic transformation characteristics have been also modified by adding Ti and RE. Thus, these elements can be considered as an efficient tool for tuning functional properties of Cu-Al-Ni SMAs.
10.1088-2053-1591-ab49cd	-1		In the present study, the Cu-30Zn alloy was selected as the experimental material, the Ni and Si elements were added to prepare a new Cu-30Zn-1Ni-0.2Si alloy. The two alloys subjected to cryogenic rolling were annealed at 300 degrees C for different times. Their mechanical, structural, and electrical properties have been characterized. The results revealed that the strength of Cu-30Zn alloy decreases severely after annealing, but the Cu-30Zn-1Ni-0.2Si alloy maintains a high strength due to the generation of Ni2Si precipitates. For example, the average tensile strength of the as-rolled Cu-30Zn alloy is 711.3 MPa, while it reduces to 562.3 MPa and 546.7 MPa after annealing for 1 h and 2 h . In contrast, the average tensile strength of the as-rolled Cu-30Zn-1Ni-0.2Si alloy is 742.5 MPa, it can be enhanced to 768.4 MPa when annealing at 300 degrees C for 1 h . Moreover, even prolonging the annealing time to 2 h, the average strength is still 701.3 MPa which is close to that of the as-rolled Cu-30Zn alloy. This study provided a feasible strategy to solve the exclusion of strength and ductility in the Cu-30Zn alloy fabricated through cryogenic rolling followed by annealing, and it may also be suitable for other Cu-Zn alloys and solid solution strengthening alloys.
10.1088-2053-1591-ab4c73	17	wear; composites; coating; friction; composite; coatings; surface; tribological; properties; wear resistance; resistance; powder; sliding; matrix; wear rate	Molybdenum disulfide (MoS2) as a two-dimensional material and solid lubricant shows good friction properties in many applications. The study used the copper (Cu) and zinc (Zn) powder with doped MoS2 powder to prepare the alloy material through the spark plasma sintering (SPS) technology. The coefficient of friction (COF) and wear of alloys with different doped ratios (0 wt%, 3 wt%, 6 wt%, 9 wt%) of MoS2 were studied by using universal mechanical tester (UMT-5), which was based the ball-on-disk method. The results show that the alloy with 3 wt% MoS2 has the lowest COF, about 0.093. The COF of composites containing 9% MoS2 are close to those of un-doped composites, 0.673 and 0.712, respectively. It is mainly owing to excessive corrosion of Cu by MoS2, resulting in increased COF and wear rate. In addition, the effect of the applied electric field on the COF of the alloy was also investigated. It was found that the electric field can increase the COF and the wear rate of the composites. As the voltage increases, oxidation of the Cu was promoted and FeSx was formed to reduce friction and wear. This work provides a new method for manufacturing and studying electrical contact friction materials.
10.1088-2053-1591-ab5514	-1		In this paper, Cu-Fe powder metallurgical alloys were firstly fabricated, and a innovative surface modification technique, high current pulsed electron beam (HCPEB), was then irradiated these Cu-Fe alloys with 5 and 10 pulses. The morphologies, microstructure and mechanical properties of the specimens both before and after HCPEB irradiation were studied. The morphologies revealed that the surface of 5-pulsed sample was melted completely, and a large amount of craters were formed. Those craters were eliminated and fused by the subsequent 10-pulsed HCPEB processing. Besides, the distribution of Fe element was fairly homogenous on the irradiated surface. Additionally, the modified microstructures consisted of refined Cu sub-grains, tiny Fe particles, Cu (Fe) solid solution and abundant defects, which played an important role in the improvement of microhardness. The HCPEB irradiated Cu-Fe samples possessed better wear resistance which was ascribed to the reduction of roughness, enhancement of hardness, and formation of lubricating film.
10.1088-2053-1591-ab583e	-1		To investigate the microstructure and mechanical properties at different deposition locations, an innovative dual wire Cold Metal Transfer (CMT) process was built to fabricate copper-aluminum alloy material with enhanced performances. Two commercial binary wires namely ERCuSi28L copper wire and ER4043 aluminum wire were fed into the common molten pool to build copper rich Cu?Al alloy samples by adjusting the wire feed speed of the two separate wire feeders. The deposited wall part showed good integrity and excellent mechanical properties, with only 15 MPa difference in ultimate tensile strength, 10 MPa difference in yield strength (YS) and 2% difference in elongation between the mechanical properties along the vertical directions. It was observed that the yield strength was higher than that of the commercially available T2-Cu. The average microhardness of the lower region, upper-middle region and upper region were 217.1 HV, 226.8 HV and 221.4 HV, respectively. Four phases were detected in the deposited sample at different location, i.e. deposited height regions. From the results it is clearly seen that the dual wire CMT process has excellent potential to produce Cu?Al components with relatively low cost and reduced lead time, thus offering a new robust and viable manufacturing route.
10.1088-2053-1591-ab5df6	-1		Researches have shown that the addition of trace amounts of rare earth element lanthanum (La) to the alloys and composites can significantly improve their microstructure and properties. In this work, Cu/Ti3SiC2/C composites with 0.05wt%, 0.1wt% and 0.3wt% La were prepared by powder metallurgy methodthrough mechanical alloying, hot-pressing (HP) and hot isostatic pressing (HIP). The effects of different La contents on the microstructure and mechanical properties of Cu/Ti3SiC2/C composites were investigated. The results show that La has a refinement effect on the grain of the matrix, and with the increase of La content, the size of the matrix of the composite becomes smaller. As the content of La increases, the performance of the composite exhibits a tendency to increase first and then decrease. The composite of 0.1wt% La exhibited the best performance with a hardness of 97.8 MPa, a tensile strength of 174.9 MPa, and a compressive strength and shear strength of 461.1 MPa and 102.1 MPa, respectively. Since the dimple is observed, the tensile fracture indicates that the fracture mode is a ductile fracture. The enhancement mechanism of La mainly includes dispersion strengthening and fine grain strengthening.
10.1088-2053-1591-ab63f8	-1		Cu-12Al-xMn (x = 0, 1, 2, 3, 4%, mass fraction) alloys were produced using powder metallurgy to investigate the effect of Mn content on the alloy's microstructure and mechanical properties. The Cu-12Al (no Mn) and Cu-12Al-1Mn (1 wt% Mn) alloys consisted of the alpha + gamma phases, where the size of the alpha grains in the Cu-12Al-1Mn alloy are much larger. Mn effectively inhibited the eutectoid transformation at a concentration above 1 wt%. Furthermore, the beta phase was converted to the beta '-martensite phase, which had a monoclinic structure after slow cooling. The phases of the alloy changed from the alpha + gamma phases to the alpha + beta ' + gamma phases with the further addition of Mn, and the tensile strength of the 3 wt% Mn alloy was 380.59 MPa. The addition of Mn did not have a significant effect on the density of the alloy.
10.1088-2053-1591-ab6c10	-1		The microstructure of the Cu-Cr alloy prepared by infiltration before and after different pressures treatment at 900 degrees C for 10 min was observed by metallographic microscope, scanning electron microscope (SEM), and transmission electron microscopy (TEM). And the mechanical properties were measured by nanoindenter, hardness tester and tensile testing machine. According to the experimental results, the effects of high pressure treatment on the mechanical properties were discussed. The results showed that the hardness of Cu matrix and Cr phase were 114HV and 194HV under the pressure of 3 GPa, which were 18.75% and 10.23% higher than those of the infiltrated alloy. Also, the hardness and compression yield strength of Cu-Cr alloy were 134 HB and 241 MPa after 3 GPa pressure treatment, respectively, 11.67%, 19.31% higher than those of the infiltrated alloy. On the basis of analysis, the high pressure treatment can improve the compactness of Cu-Cr alloys, promote the precipitation of nanometer Cr particles and increase the hardness and elastic modulus of Cu matrix and Cr phase, resulting in the improvement of hardness and compression yield strength in Cu-Cr alloys. In the range of 1 similar to 6 GPa, the hardness and compression yield strength of alloys increase with the increase of pressure. However, these mechanical properties of Cu-Cr alloy increases slowly when the pressure exceeds 1 GPa.
10.1088-2053-1591-ab6e3b	-1		Microstructure and tribological properties had been studied in a Cu-Ti-1%TiCMMC with titanium concentration of 10%, 15%, and 20%. The composite was manufactured following the pulvimetallurgical route that included: mechanical and ultrasonic mixing in 2-propanol, compaction at 400 MPa and sintering assisted by abnormal glow discharge in an atmosphere of 10% nitrogen and 90% argon. The discharge was established in the direct current regime and the voltage values were adjusted according to the sintering temperatures of 750 degrees C and 850 degrees C. The sintering process was carried out for 30 min and then cooled in the same atmosphere. As a result, a differentiated in morphology and wear properties were obtained in the sintered parts. At 750 degrees C a microstructure characterized by the stability of Ti grains with intermetallic precipitates such as CuTi2 and CuTi were observed at the interface with the matrix. On the other hand, the intermetallic phases as Cu3Ti, Cu4Ti and CuTi2 had been detected in the sintered at 850 degrees C. These phases were related to diffusive processes that occurred during the sintering, enhanced by the energy provided by the process. It had been observed that with increase of titanium content an improvement of the MMC tribological properties. In titanium contents of 20% at 750 degrees C was estimated a wear coefficient of 2.7 x 10(-8) mm(3).N-1.m(-1) with a track width of 312 mu m. Despite the pores originated during the sintering of MM Cat 850 degrees C was found a wear coefficient value of 2.4 x 10(-8) mm(3).N-1.m(-1) and a track size of 778 mu m, related to the plastic deformation exerted on the porous structures during the wear process. Results of the tribological analysis lead that this compound may be applied in fields where the balance between adequate tribological properties and lightness are highly required such as the automotive, aeronautical and biomedical industries.
10.1088-2053-1591-ab8b1d	-1		This paper presents a systematic study of the precipitation strengthening mechanism in polybasic Cu-Ni-Mn-Fe alloy. The effect of aging treatment on the microstructure, morphologies and phase transition of the Cu-Ni-Mn-Fe alloy were analyzed and discussed using scanning electron microscope (SEM), transmission electron microscope (TEM), X-ray diffraction (XRD) and differential scanning calorimeter (DSC), respectively. The -MnNi precipitates with a size of 50-100 nm, mainly formed during aging, were considered as the source of the aging strengthening. In addition, there is a semi-coherent between the plane (111) of the -MnNi precipitates and the plane (200) of the alpha-Cu matrix. The density of -MnNi precipitates increases with the increase of the aging time. The hardness, yield strength and ultimate tensile strength of the aged alloy increase from 127 to 366HB, 217 to 788 MPa, and 433 to 842 MPa, respectively, which is attributed to precipitation strengthening.
10.1088-2053-1591-ab9778	15	aging; strength; conductivity; electrical conductivity; electrical; mpa; treatment; strengthening; degrees; cu-; cold; precipitation; tensile strength; tensile; iacs	The strength and conductivity of Cu-Cr-In alloys with trace La and different processing states were compared. Then, the influence of La on the structure and properties of the Cu-Cr-In alloy and the associated mechanisms were analyzed. The mechanical properties and microstructural evolution of the alloy were investigated via scanning electron microscopy, transmission electron microscopy, and tensile strength measurements. The results showed that the addition of 0.07wt% La to the Cu-Cr-In alloy had the effect of purifying the alloy melt and removing impurities, which improved the electrical conductivity of the alloy. However, the formation of rare earth intermetallic compounds reduced the tensile strength of the Cu-Cr-In-La alloy. After thermomechanical treatment, the Cu-Cr-In-La alloy reached a peak strength of 457 MPa and a conductivity of 85% IACS.
10.1088-2053-1591-abc4b4	15	aging; strength; conductivity; electrical conductivity; electrical; mpa; treatment; strengthening; degrees; cu-; cold; precipitation; tensile strength; tensile; iacs	The Cu-Ni-Mn-Fe alloy is prepared to study its precipitation behavior and mechanical properties during aging under elevated compression stresses. Transmission electron microscopy (TEM), scanning electron microscopy (SEM), x-ray diffraction (XRD), hardness and tensile tests are used for this investigation. The results indicate that the stress-aging treatment leads to the formation of fine, equiaxed grains and twins within the matrix of Cu-Ni-Mn-Fe alloy. During the stress-aging, the density of -MnNi precipitates initially decreases and then increases. The stress is further increased from 220 to 385 MPa, the vacancy concentration and dislocation density increase rapidly owing to creep deformation, while the strain-induced effect accelerates the precipitation of -MnNi. The results show that the tensile strength and hardness of Cu-Ni-Mn-Fe alloy initially decrease and then increase, and the tensile strength and hardness of the Cu-Ni-Mn-Fe alloy are 890 MPa and 274 HB under the compressive stress of 385 MPa, and the elongation remains at 8.72%. It is mainly attributed to the application of compression stresses during aging, which can enhance both the strength and ductility of the alloy.
10.1088-2053-1591-abc653	-1		In planar flow casting (PFC) process, the molten alloy from nozzle exerts cyclical thermal shock on the substrate surface of cooling wheel and the cyclical thermal shock causes damage to the substrate surface in the form of defects. In this paper, a 2D numerical model was explored and the cyclical thermal shock on the surface of cooling wheel was simulated by numerical method using practical casting parameters. A batch of hot rolled copper-beryllium (Cu-2Be) cylindrical rings was prepared and subjected to solution annealing and aging treatments. The coefficients of thermal conductivity, thermal expansion coefficients and mechanical properties of Cu-2Be rings with different aging conditions were measured. The metallograph and SEM of the Cu-2Be rings subjected to 10(5) cycles of thermal shock were examined. The simulation results show that the surface temperature underneath the puddle is heated up drastically to a maximum temperature around 350 degrees C and cooled down to a minimum temperature around 140 degrees C in each revolution in quasi-steady process, and the lower thermal conductivity leads to the higher surface temperature for Cu-2Be substrate. The mechanical and physical responses of a Cu-2Be alloy aged at different conditions as a substrate of cooling wheel have been investigated after 10(5) cycles of thermal shock in practical casting. It was observed that the cyclical thermal shock leads to damage to Cu-2Be surface which affects the surface quality of as-cast ribbon. It was found that higher thermal expansion coefficient of Cu-2Be alloy leads to large magnitude of surface expansion and surface shrinkage which results in crack damage while lower thermal expansion coefficient of Cu-2Be alloy resulting from higher temperature aging is benefit to reducing the magnitude of surface expansion and surface shrinkage but the strength of Cu-2Be substrate is also reduced and intergranular erosion occurs after 10(5) cycles of thermal shock.
10.1088-2053-1591-abd217	-1		The vacuum horizontal continuous casting method was used for preparing Cu-4.5 wt% Ag alloy rod containing few oxygen. The evolution of microstructure was observed by metallographic microscope (OM), scanning electron microscope (SEM) and transmission electron microscope (TEM). The results showed that the hardness and electrical conductivity of Cu-4.5 wt% Ag alloy aged at 450 degrees C for 12 h were increased by 60 HV and 12 %IACS than solution treated alloy. TEM observation showed that the continuous precipitates of Ag are uniformly distributed in matrix with the form of particles and strips. Through calculation, the strength increment of peak aged Cu-4.5 wt%Ag alloy from solid solution hardening and precipitation hardening are 86 MPa and 136 MPa, respectively.
10.1088-2053-1591-abd2f6	-1		Carbon nanotubes (CNTs) reinforced Copper (Cu) matrix composite powders have been successfully prepared by in situ chemical vapor deposition (CVD) using Cu-0.6 wt% Al alloy powders without additional catalyst. The catalyst for CNTs growth is nano-copper particle (similar to 28 nm), and the interaction between Cu and Al2O3 would promote the formation of nano-copper particles (similar to 28 nm). The high quality multi-walled CNTs obtained dispersed uniformly on and well bonded to the composite powders. And the formation mechanism was discussed, the results show that part of the growth of CNTs follows tip-growth mode and the others without catalyst particles at the top follow the base-growth mode. This providing a simple and effective method for in situ preparation of CNTs/Cu composite powder with uniform dispersion of CNTs.
10.1088-2053-1591-abd2f9	17	wear; composites; coating; friction; composite; coatings; surface; tribological; properties; wear resistance; resistance; powder; sliding; matrix; wear rate	Fe-Cu-Ni-Sn-Graphite oil-bearing self-lubricating composite was prepared using powder metallurgy method through multiple sintering-rolling processes and oil impregnation vacuum-assisted method. The tribological property of the composite were characterized by a UMT-2 tribometer. And the micro-structure and worn surface of composite were investigated by an optical microscope, SEM (scanning electron microscopy), XRD (X-Ray Diffraction) and EDS (energy disperse spectroscopy). The results show that the porous oil-bearing self-lubricating composite exhibit an excellent long-term low-friction and antiwear properties. Especially, the friction coefficient of the composite after secondary rolling and sintering decreased by 38% compared to that of the sample without sintering-rolling. After sliding for 21 h, the friction coefficient of the composite still keep relatively stable at a low value. In addition, the wear resistance of the composite has greatly improved after secondary rolling and sintering. And the wear loss of the 40Cr counterpart is almost wear-free and presents oil-graphite mixture around the wear track, which reveals that solid-liquid synergetic lubrication is the potential lubrication mechanism during the sliding process.
10.1088-2053-1591-abde11	-1		In recent years, the commercially available Cu-Sn alloy has attracted great interest within the new energy vehicles and industrial robots industries because of its relatively excellent comprehensive performance as compared to those of Cu-Ag and Cu-Mg alloys. In this work, we study the possibility of improving the tensile strength of Cu-Sn alloy via Mg addition. Our results show that, the addition of Mg could significantly improve the strength of the Cu-Sn alloy, the tensile strength of the Cu-Sn alloy was increased from 399MPa to 427MPa by 0.02 wt% Mg addition after 80% cold-rolled reduction. This can be ascribed to the combined effect of the acceleration of the grain refinement and the promotion of the sub-structures formation by Mg addition during cold rolling process. Larger number density and more uniformly distributed sub-structures with an average size of 120 nm were formed in Mg-contained alloy than that in Mg-free alloy after 80% reduction. However, the Mg addition slightly decreased the electrical conductivity (EC) of the alloy (1.5%IACS), because of the lattice distortion caused by Mg atoms.
10.1088-2053-1591-ac017c	2	corrosion; surface; film; electrochemical; films; spectroscopy; layer; current; solution; potential; resistance; composition; x-ray; ions; showed	Cu-Al-N thin films were deposited by means of the unbalanced magnetron cosputtering technique, varying the pulsed DC source power that is associated with the aluminum target. The structural characterization, done through x ray difraction (XRD) and transmition electronic microscopy (TEM), showed that the films were nanocrystalline, with a crystallite size of an order of magnitude of 10 nm. According to the chemical composition results, they consisted of a Cu-Al phase, copper nitride and aluminum nitride, that depended on the deposition power. The electrochemical characterization was performed by means of Tafel extrapolation and electrochemical impedance spectroscopy (EIS). The Tafel results showed a decrease in the corrosion current with an increase in the power, and the electrochemical impedance results showed an inductive behavior at low frequencies.
10.1088-2053-1591-ac045d	-1		High-performance copper-based pantograph slide materials play a crucial role in the rapid development of modern urban rail transit urgently. Herein, a full density graphite/copper-alloy matrix composite for pantograph slide has been successfully obtained by the hot powder forging process. The composite exhibits the full density when forging energy density is 307.6 J cm(-3). In addition, the influence of different aging treatments on microstructure and mechanical performances of the composite has been studied in detail. The hardness and resistivity of the forged materials are greatly improved after an optimum aging treatment. Simultaneously, the friction and wear performances with or without currency current have been investigated, which demonstrates the friction coefficient can reach the minimum of 0.109 under 35 N. In current-carrying friction, the wear rate of the composite is an extremely small value of 5.5 x 10(-5) mg m(-1) after the aging treatment, indicating the outstanding anti-friction and self-lubricating performance. All the comprehensive analyses illustrate the full density graphite/copper-alloy matrix composite with excellent mechanical shows an enormous potential for pantograph slide.
10.1088-2053-1591-ac2696	-1		Upward continuous casting is the key process in the production of contact wire for electric railway. The stability of the process and the quality of the produced billet are directly related to the performance of the contact wire and ultimately the safety of the railway operation. To ensure the quality of continuous-casting billet, the optimal process conditions need to be experimentally determined, which is not only costly but also time-consuming. To facilitate this optimisation process, the simulation of the solidification process of Cu-0.45%Sn alloy in upward continuous casting is described in this paper to assess the influence of casting temperature, upward continuous casting speed, the time of stop-pull, and primary cooling water flow rate on the liquid core length . The results show that the speed of upward continuous casting exhibits a great influence on the liquid core length, while the casting temperature has only little influence. In a certain range of the ratio of stopping time to pulling time, the quality of updraft Cu-0.45%Sn alloy billet is improved; exceeding a certain ratio results in a decrease of the surface quality and an increase in internal and external defects. The liquid core length of the continuous casting rod decreases with the increase of the cold water flow rate, and properties are stable when the flow rate reaches 0.45 m(3)center dot h(-1). For a billet with a diameter of 20 mm, the appropriate upward continuous casting process parameters are determined as a casting temperature of 1175 degrees C, an upward continuous casting speed not exceeding 25 cm center dot min(-1), a ratio of stopping time to pulling time not exceeding 2.13, and a cooling water flow rate of 0.45 m(3)center dot h(-1).
10.1088-2053-1591-ac31ff	17	wear; composites; coating; friction; composite; coatings; surface; tribological; properties; wear resistance; resistance; powder; sliding; matrix; wear rate	Owing to good self-lubricating performance, tin bronze is widely used in industrial fields. As tin bronze parts manufactured by powder metallurgy, their tribological performances are influenced by raw powder. In this work, four types of self-lubricating copper alloy composites (CuSn10 (D), CuSn10, CuSn10Pb10 (D) and CuSn10Pb10) were prepared by sintering completely alloyed powder and diffusion alloyed copper tin powder. The morphology, element distribution and microstructure of raw powder and their sintered Cu alloy composites were observed. The tribological properties of Cu alloys were investigated by block-ring friction test under different working conditions and their worn surface and wear debris were analyzed. The results show that the diffusion alloyed powder has an irregular dendritic morphology and its sintered Cu alloy is more likely to produce twin structure which enhances the hardness and the bearing capacity of the material. Compared with completely alloyed powder sintered CuSn10 sample, the wear rate of CuSn10 (D) sintered from diffusion alloyed powder was reduced by 83.96%, 74.39%, and 67.63% under three typical working conditions. Under dry friction conditions, the wear rate of CuSn10 (D) is reduced by 63.64% than CuSn10, and CuSn10Pb10 (D) is 25% lower than CuSn10Pb10. The investigation on the wear tracks and wear debris of Cu alloy composites showed that the diffusion alloyed powder sintered samples are inclined to form a more consecutive and integral third-body layer on wear tracks and which contributes to the better wear resistance.
10.1088-2053-1591-ac4407	15	aging; strength; conductivity; electrical conductivity; electrical; mpa; treatment; strengthening; degrees; cu-; cold; precipitation; tensile strength; tensile; iacs	A Cu-Ni-Si alloy with high Ni and Si contents was prepared by the traditional melting and casting method, and then multiple forging and ageing were conducted to investigate their effect on the microstructure and properties. The results show that reticular Ni31Si12 phases are located on the grain boundaries of the dendritic alpha-Cu(Ni, Si) solution matrix in the as-cast Cu-Ni-Si alloy because of the high Ni and Si contents, and some rice-like Ni2Si phases precipitate in the interior of alpha-Cu(Ni, Si) grains during cooling. With increasing number of forging passes, the morphology of the alpha-Cu(Ni, Si) matrix changes from dendrites to elongated dendrites and then equiaxed grains, the Ni31Si12 phase changes from reticular to irregular and then particle-like, while the Ni2Si phase gradually disappears. As a result, the hardness increases continuously up to 18 forging passes, while the electrical conductivity first increases and then decreases significantly. The hardness and electrical conductivity achieve the highest values with 18 forging passes and a subsequent ageing treatment at 450 degrees C for 4 h, and the corresponding microstructure comprises an equiaxed alpha-Cu(Ni, Si) matrix with microscale Ni31Si12 particles and sub-microscale Ni2Si precipitates.
10.1088-2053-1591-ac440a	-1		Graphite flake-carbon fiber coreinforced copper matrix composites were prepared by vacuum hot pressing technology. The carbon fibers were dispersed ultrasonic in alcohol and then mixed with graphite flake and alloys powder (Zr and Cu) for hot pressing sintering. The effects of the carbon fiber content on the microstructure, bending strength and thermal conductivity of the composites were investigated. The results show that the interface of the composites is well bonded. When the volume fraction of carbon fiber is 1%-3%, the carbon fiber can be uniformly dispersed in the matrix, and the bending strength of the composites can be improved effectively. When the volume fraction of carbon fiber is 2%, the bending strength reaches a maximum of 152 MPa, which is an increase of 60% compared with that of the composites without carbon fiber. However, an excessive addition of carbon fiber (4% or more) leads to an uneven distribution of carbon fiber, and the bending strength of the composites decreases. When the volume fraction of carbon fiber is 2%, the thermal conductivity of the composite is 597 W center dot m(-1)center dot K-1. The acoustic mismatch model (AMM) associated with the Digimat MF module is able to predict the thermal conductivity of the anisotropic multiphase composites.
10.1088-2053-1591-ac49bd	8	hot; deformation; strain; strain rate; dynamic; hot deformation; recrystallization; dynamic recrystallization; flow; rate; flow stress; compression; constitutive; degrees; stress	This paper presents a study on plastic deformation behavior of Cu-50Ta alloy at temperatures of 286-473 K and strain-rate of 0.01-6200 s(-1). The effects of temperature, strain-rate, and strain on the yield strength, flow stress, and strain-rate sensitivity coefficient were determined. A phenomenological model was established to predict variation of the strain-rate sensitivity coefficient for Cu-50Ta alloy under dynamic compression. A Johnson-Cook constitutive model was established to predict the equivalent stress-equivalent plastic strain relationship under extreme deformation (high temperature and strain-rate). The results showed that the plastic deformation behavior of Cu-50Ta alloy was affected by temperature, strain-rate, and strain. The material exhibited obvious strain-rate strengthening and thermal softening. As the strain-rate increased, the yield strength logarithmically increased. At a temperature of 286 K, the strain-rate increased from 0.01 s(-1) to 6200 s(-1), and the yield strength increased from 543.75 MPa to 881.13 MPa. In addition, the yield strength linearly decreased as the deformation temperature increased. Under conditions of dynamic deformation, the variation of strain-rate sensitivity coefficient could be expressed as a function of strain-rate and strain. The phenomenological model accurately described the variation of the strain-rate sensitivity coefficient of Cu-50Ta under dynamic deformation conditions. The Johnson-Cook constitutive parameters, calibrated by experimental data, described the plastic deformation behavior of the alloy under high-velocity impact.
10.1088-2053-1591-ac5775	-1		To study discontinuous precipitation, which is an important method for strengthening materials, we observed the nucleation and growth of discontinuous precipitates in Cu-Ag alloys using electron backscatter diffraction and scanning transmission electron microscopy. We found that discontinuous precipitation always started with Ag precipitates, which nucleated on Cu grain boundaries. These precipitates then each took the shape of a large, abutted cone that shared a semi-coherent interface with one of the Cu grains, topped by a small spherical cap that shared an incoherent interface with the Cu grain on the opposite side of the boundary. This formation created a difference between the levels of interface energy on each side of boundary. We assume that this difference and boundary curvature together generates the driving force necessary to push grain boundary migration, thus triggering discontinuous precipitation. Because of grain boundary migration, Ag solute was consumed at one side of the grain, which causes a solute difference. The difference produces mainly driving force, pushing the boundaries to migrate forward.
10.1088-2053-1591-ac6ed1	-1		The Cu-Cr immiscible alloys were prepared by arc melting. The effects of Cr addition and electromagnetic stirring on the phase separation, microstructure were examined. The results show that serious phase segregation occurs at the center of the sample with increasing Cr contents, forming a sandwich like structure. The shape of the primary Cr transforms from fine dendrite to more developed dendrite. Thermodynamic analysis indicates that Cr addition increases the driving force for the liquid phase separation. The electromagnetic stirring can facilitate elative motion between the Cr droplets and the melts, and thus intensify the segregation phenomenon. With Cr additions, the hardness in non-segregated area shows only slight increase, and in Cr segregated area shows a significant increase. While the electrical conductivity shows only slight decrease with increasing Cr content.
10.1088-2053-1591-ac7516	13	clusters; atomic; glass; atoms; composition; dynamics; metallic; icosahedral; glasses; simulations; molecular; cu-zr; molecular dynamics; metallic glasses; structural	The atomic-level structures of the icosahedral clusters in Cu-Zr-Al ternary metallic glasses were studied via the first-principles theory. The rules of icosahedra stability were determined. Icosahedra with a better chemical order or with a better symmetry exhibited a better stability. The strong connectivity between Al atom and Cu and Zr atoms was observed as demonstrated by the obvious degree of 'bond shortening'. The Al atom contributed more to the structural stability when used as the central atom than the other atoms. Therefore, the addition of even a small amount of Al atom to the Cu-Zr binary system remarkably improved the stability of the icosahedron structures. The continued addition of Al atoms had a lower contribution to the improvement to the glass-forming ability of the Cu-Zr-Al alloys.
10.1088-2053-1591-ac8d4f	-1		The Al contents play an exceedingly important role in Cu-Al system shape memory alloys (SMAs), and Cu-Al-Fe alloy represents the new development directions of Cu-Al system SMAs. The Cu-xAl-4Fe (x = 11, 13, 15 wt%) alloys, which take the powder core wire with a structure resistant to element burning as additive manufacturing materials, were prepared by arc melt deposition process. In this work, the as-deposited, quenched and deformed microstructure was studied in detail by utilizing OM, SEM, and XRD. The shape memory properties of the alloys were analyzed by the bending tests. The effect mechanism of the Al content on the shape memory properties of Cu-Al-Fe alloys was also investigated. Results show that the as-deposited microstructure presents sub-eutectic to hyper-eutectic characteristics with the rise in Al content. After quenching, the microstructure of 11 wt% Al, 13 wt% Al, and 15 wt% Al alloys are the alpha' martensite, the beta (1)' martensite, and the beta (1) austenite with high order degrees. Under 4% pre-strain, the shape memory recovery rate of the 13 and 15 wt% Al alloy is 100%, but the shape memory recovery rate of 11 wt% Al alloy is only 22.6%. However, compared with the ductility of 11 and 13 wt% Al alloy, that of 15 wt% Al alloy is poor, which causes failure to withstand 4% bending pre-strain. After bending deformation, cracks of 15 wt% Al alloy along the crystals appear and cause the memory strip to break. The analysis indicates that the properties of Cu-Al-Fe alloy have an intense sensitivity to the Al element. The martensitic order degree of the alloy is elevated with the increase in the Al content, and the grain interface gradually becomes sharper. Solidification impurities are formed at the grain boundary during the additive manufacturing process due to the influence of the interface energy. At the same time, the invading O-2 combines with the more active Al element to form metal oxidation, which markedly reduces the grain boundary strength and the bending strength of the alloy. As a result, the shape memory properties cannot be reflected in the case of high Al content.
10.1088-2053-1591-acaa20	-1		The realization of high strength of copper-iron (Cu-Fe) alloy is related to its solidification structure. The morphology and distribution characteristics of Fe phase in the solidification structure of Cu-15Fe alloy ingot were analyzed, and the deformation strength of the alloy was compared. The results show that the cooling conditions can affect the size, morphology and distribution of Fe phase in the solidified structure. The average distribution uniformity in the water-cooled copper mold ingot (W-ingot) is 0.45% higher than that in the quartz mold ingot (Q-ingot). The distribution quality of Fe phase in solidification structure can be evaluated by fractal dimension and average Fe phase area. The larger the fractal dimension is, the smaller the average Fe phase area is, where Fe phase is smaller and more uniform in the corresponding region. In the experiment, the strength of the strip increased from 510 to 547 MPa corresponds to the Q-ingot and the W-ingot.
10.1088-2053-1591-acb1a0	16	wear; composite; composites; powders; milling; particles; powder; wt; sliding; friction; hardness; matrix; mechanical; surface; properties	Copper/Diamond composites have gained a lot of attention in recent years due to their excellent thermal conductivity and their potential for use in high-power electronic devices. The current work targets on an experimental investigation of the tribological,mechanical, and thermal behaviour of copper diamond composite by using reinforced micro-diamond particles. Copper matrix composites with varying weight percentages of diamond particles were produced with the aid of the powder metallurgy. The wear tests were carried out on Pin-on-Disc wear test machine as per ASTM G99. The doping of an optimum amount of diamond particles (1% wt.) improved the overall wear performance by 51% under a normal load of 80 N. The doping had also showed a significant improvement in hardness by 26% and thermal conductivity by 1%. The primary wear mechanisms of Cu-Diamond composites appear to be a combination of brittle fracture, fragmentation of diamond-reinforced particles and ploughing in the Cu-alloy matrix.
10.1088-2053-1591-ace02d	-1		In this study, we performed electric pulse treatment (EPT) on the cold-rolled pure copper sheets. And the effects of the current density of EPT on the microstructure and mechanical properties of the cold-rolled pure copper sheets were investigated. It has been found that the change in the current density of EPT has a remarkable influence on the surface temperature, microstructure, strength, plasticity and microhardness of the samples. Compared with the untreated sample, the elongation after fracture increased by about 3.2 times at a current density of 200 A mm(-2), whereas the ultimate tensile strength decreased by only 38.0%. Microstructures indicate that the electric pulse can induce rapid recrystallization in cold-rolled pure copper sheets within a short time, while reducing the dislocation density, weakening the rolling textures and increasing microstructure uniformity, thereby improving the plasticity of the material. Therefore, the present research has the potential to provide an effective alternative way to the traditional heat treatment of copper sheets and strips.
10.1088-2053-1591-ad37a4	-1		The Parallel Tubular Channel Angular Pressing Process (PTCAP) has emerged as a promising method for refining the grain structure and enhancing the mechanical properties of metallic materials through severe plastic deformation. This study focuses on a comprehensive investigation of the PTCAP process, combining experimental and numerical analysis to gain insights into its underlying mechanisms. Experimental investigations involve processing a commercially pure copper tube using PTCAP under controlled conditions. In parallel, an explicit numerical analysis is developed using ABAQUS software to simulate the deformation behavior during PTCAP. The model incorporates material constitutive equations and accounts to describe the material response under high strain rates and large deformations. The research aims to investigate how multi-pass PTCAP affects hardness, strain homogeneity, and stress distribution. A comparison between the load punch from the experimental and FEM is conducted to validate the FEM results, and there is a good correlation between both . Hardness measurements are conducted at various stages to quantify the changes in material hardness resulting from the successive PTCAP passes. The hardness of the Cu tube increased by 63.45, 94.51, 103.98, and 105.64% after 1 to 4 passes, respectively.
10.1088-2053-1591-ad3e4f	1	shape; memory; shape memory; damping; martensite; martensitic; damping capacity; transformation; capacity; strain; superelasticity; temperature; cu-al-mn; shape memory effect; effect	The effect of thermal quenching procedures on the damping properties of Cu-Zn-Sn-based SMAs is reported. Three compositions of Cu-Zn-Sn-based SMAs designated A (Cu-15.6Zn-12.1Sn), B (Cu-26.1Zn-9.3Sn), and C (Cu-29.6Zn-8.9Sn) samples produced by the casting process were subjected to direct quenching, up-quenching, and step-quenching treatments. The microstructure of the samples was examined using the backscattered electron microscope with fixtures for energy-dispersive spectroscopy analysis. The damping properties were assessed on a dynamic mechanical analyzer and presented in terms of tan delta. The microstructures of Cu-Zn-Sn-based SMAs consist of gamma-Cu5Zn8 and Cu4 major phases containing some black dot precipitation and a small amount of white circular precipitates in the parent phase. For the A alloys, the step-quenched samples exhibited the highest damping capacity with peak internal friction of 0.041 at 37 degrees C, which is greater than 0.028 at 37 degrees C and 0.26 at 25 degrees C obtained for the up-quenched and direct-quenched samples respectively. The step-quenched B alloys show the highest damping capacity with peak internal friction of 0.104 at 227 degrees C, which is far greater than 0.053 at 23 degrees C and 0.034 at 35 degrees C obtained for the up-quenched and direct-quenched samples respectively. For the C alloys, the up-quenched samples show the highest damping capacity with peak internal friction of 0.053 at 235 degrees C, which is greater than the peak values of 0.037 at 23 8 degrees C obtained for the step-quenched samples. Direct-quenched samples gave the lowest damping capacity with a peak value of 0.027 at 235 degrees C. In general, step-quenching treatment effectively improved the damping properties of Cu-Zn-Sn-based SMAs.
10.1088-2053-1591-ad76fc	-1		This study investigates the impact of Computer Numerical Control (CNC) milling parameters on Cu-Al-Mn SMAs (Shape memory alloys) to evaluate the effects on Surface Roughness (SR) and Material Removal Rate (MRR). The primary variables examined comprise of cutting speed, feed rate, and depth of cut. Results indicate that the Shape Memory Effect (SME) is higher in Copper Aluminium Manganese (CAM 3) compared to CAM 1 and CAM 2, with SME improving from 3.5% to 5.5% as Manganese (Mn) content increases, reflecting an increase in dislocations within the metal's crystal structure. Surface roughness increases with higher feed rates and depths of cut but decreases with increased cutting speed. MRR shows a positive correlation with feed rate, depth of cut, and cutting speed, though it decreases with higher Mn content. Notably, CAM 3 exhibits lower MRR compared to CAM 1 and CAM 2. Scanning Electron Microscopy (SEM) reveals that at lower feed rates (0.10 mm rev-1), the surface is smooth and free of ridges or feed marks, while at higher feed rates (0.18 mm rev-1), noticeable surface imperfections and plastic deformation occur. The addition of Mn improves surface smoothness and machinability, it also affects MRR. Further suggesting that Mn content and milling parameters significantly influence both the mechanical properties and machinability of Cu-Al-Mn SMAs respectively.
10.1088-2053-1591-ada5c5	-1		To reduce the amount of copper used and improve the service life of the copper layer in the plunger pair of a plunger pump, Ni15 was chosen as the transition layer to assist in the laser cladding preparation of copper-steel composite materials. WC-12Ni powder was mixed into Cu powder at concentrations of 5, 10, 15, 20, 25 wt%, and different compositions of cladding layers were prepared using laser cladding technology. The microstructure of the cladding layers was analyzed by optical microscopy (OM), scanning electron microscopy (SEM), and energy dispersive x-ray spectroscopy (EDS). The microhardness of the composite coatings was tested using microhardness Vickers (MHV), and the tribological performance of the composite coatings was evaluated using the friction and wear testing machine (F&WM). The results showed that, in terms of microstructure, element diffusion occurred around the WC particles, and partial dissolution of WC particles at their sharp corners led to the formation of new compounds with other elements. Additionally, WC particles contributed to the refinement of the microstructure. In terms of performance, the microhardness of the composite coatings increased with the increase in WC-12Ni content, reaching a maximum of 412.5 HV0.1 when the content was 25 wt%. Regarding tribological properties, the composite coating with 20 wt% WC-12Ni exhibited excellent friction-reducing properties, with a stable coefficient of friction of 0.53. Both the 20 wt% and 25 wt% WC-12Ni composite coatings demonstrated good wear resistance, with wear rates of 4.4 x 10-4 mg/ Nm.
10.1088-2631-7990-ad9367	-1		Nanocrystalline (NC) metals and alloys are prone to mechanical and thermal instability under force and thermal fields due to their high Gibbs free energy, which limits their industrial applications. In this work, by employing rotary swaging (RS), bulk NC Cu-15 at% Al alloys with both high strength and high thermal stability were prepared. Quasi-static tensile test results show that the yield strength is 1016 MPa. Moreover, the grain growth temperature was retarded up to 0.4 T-m, higher than the literature values. Microstructural characterizations revealed that after RS deformation, coarse-grained Cu-Al was refined into fibrous NC grains with a diameter of 45 nm and a length of 190 nm, and the contents of high-angle grain boundaries (GBs), low-angle GBs, and twin boundaries are 17%, 45%, and 38%, respectively. Moreover, there is a significant multiscale chemical fluctuation within the grains, at the GBs, and between the grains through extreme defect accumulation. The atomistic simulation suggests that the segregation behavior of Al solute is essentially driven by the atomic size and local stress state. Besides, Al segregation greatly reduces the grain boundary energy, which further improves the thermal stability of the material. The main strengthening mechanism is Hall-Petch strengthening and the strengthening brought by the chemical fluctuations. Our work provides ideas for designing strong and thermally stable bulk NC alloys.
10.1089-3dp.2020.0192	-1		The selective laser melting (SLM) process of the Cu-10Sn alloy and effects of heat treatment were examined in this study. The Taguchi test and Box-Behnken design were performed to determine the laser power (LP), scanning speed (SS), and hatch space (HS). The best process parameters were selected using the highest density: the optimum HS was 160 mu m; SS was 278 mm s(-1); LP was 192 W; and density reached 98.76%. The tensile strength, elongation, Vickers hardness, and impact toughness of the Cu-10Sn alloy formed by SLM are 435 MPa, 13%, 122HV1, and 10 J center dot cm(-2), respectively. Heat treatment can significantly increase the ductility and impact toughness of the Cu-10Sn alloy, but at the same time, it can reduce its strength . The strength of parts obtained by all five heat treatment methods is much greater than that of castings. Parts that are annealed at 600 degrees C for 4 h have the best mechanical properties, its tensile strength and elongation were 378 MPa and 15%, respectively.
10.1089-3dp.2021.0242	-1		Advances in selective laser melting (SLM) of metals in the past two decades have made metals additive manufacturing more accessible for industrial adoption. Despite printing process improvements, post-processing of SLM components has not improved much, resulting in considerable costs, delay, and design limitations. Building upon recent advances in sensitization-based self-terminating etching processes, this work details a new set iodine-based sensitization and etching chemistries that simplify the post-processing of copper (Cu) alloy components fabricated using SLM. This work demonstrates that iodine can be used to sensitize the surface of copper alloy components to form soluble copper iodide salt that can be then dissolved in common solvents, such as acetonitrile. This process removes a predefined amount of material from all interior and exterior surfaces in a self-terminating manner, enabling facile removal of internal and external supports, removal of any trapped powder, and the smoothing of interior and exterior surfaces. We demonstrate this process on GRCop (Cu-chromium-niobium) alloys due to their widespread use by the rocket propulsion industry along with a demonstration in copper (110) for applications in heat exchangers and electromagnetic transmitters/receivers. Our results provide the first systematic study on the effect of iodization temperature and duration on the thickness of the iodide region in GRCop-84 components. Additionally, the surface roughness before and after each iodization-dissolution was also quantified for GRCop-84 and showed 70% reduction in R-a roughness from a high of 10 mu m as-printed to a low of 3 mu m after four iodization-dissolution cycles.
10.1093-jmicro-dfw003	-1		In this study, new microscopy techniques were developed for understanding the mechanism for the bainitic transformation in a Cu-17Al-11Mn (at%) alloy. An orthogonally arranged focused ion beam and a scanning electron microscope were employed to observe three-dimensional (3D) morphology of the bainite phase, in addition to compositional analysis by using a scanning transmission electron microscope equipped with a double-detector energy-dispersive X-ray spectrometer system. The 3D morphology of these samples was observed at different aging times and aging temperatures; the results obtained indicated that with increasing aging time and/or aging temperature, the bainite phase at the initial stage of formation exhibits a plate-like shape, which changes to a lenticular form. A habit plane was uniquely determined as similar to{9 3 2} by the combination of 3D image reconstruction and an electron back-scattered diffraction technique. The compositional analysis revealed the spatial distribution of the compositional variation between the bainite and matrix phases in the initial stages of the transformation. In the bainite phase, the Cu concentration was higher, while the concentrations of Al and Mn were lower than those in the surrounding matrix, indicative of the diffusion of the constituent elements with the growth of the bainite phase.
10.1098-rsos.181278	2	corrosion; surface; film; electrochemical; films; spectroscopy; layer; current; solution; potential; resistance; composition; x-ray; ions; showed	The anodic dissolution behaviours of Cu, Zr and Cu-Zr alloy were analysed in LiCl-KCl at 500 degrees C by anode polarization curve and potentiostatic polarization curve. The results show that the initial and fast-dissolving potentials of Cu are -0.50 and -0.29 V, and Zr are -1.0 and -0.88 V, respectively. But, in the Cu-Zr alloy, the initial and fast-dissolving potentials of Cu are -0.52 and -0.41 V, and Zr are -0.96 and -0.92 V, respectively. The potentials satisfy the selection dissolution principle that Zr in the alloy dissolves first, while Cu is left in the anode and is not oxidized. The passivation phenomenon of Zr is observed in the quick dissolution of Zr, while it is not observed in the Cu-Zr alloy. Moreover, from the above anodic dissolution results, potentiostatic electrolysis of Cu-Zr alloy was carried out at -0.8 V for 40 min, and the anodic dissolution mechanism and kinetics of Zr in Cu-Zr alloy were also discussed. In the initial stage, Zr dissolves as Zr4+ ions from the alloy surface and enters into the molten salt, leaving a Cu layer called 'dissolving layer' on the surface of the alloy. After that, another layer between the matrix and 'dissolving layer' called 'diffusion-dissolution layer' appears. Zr diffuses in the alloy matrix and dissolves as Zr4+ ions on the surface of the 'diffusion-dissolution layer' continuously, and Zr4+ ions diffuse through the 'dissolving layer' and enter into the molten salt finally. In addition, the factors affecting the dissolution of Cu-Zr alloy, such as time and potential, were also investigated. The dissolution loss increases with the increasing dissolution potential and time, while the dissolution rate increases with the increasing dissolution potential and declines with the prolonging dissolution time.
10.1103-PhysRevB.100.045135	13	clusters; atomic; glass; atoms; composition; dynamics; metallic; icosahedral; glasses; simulations; molecular; cu-zr; molecular dynamics; metallic glasses; structural	The ground-state equilibrium properties of copper-gold alloys have been explored with the state-of-the-art random phase approximation (RPA). Our estimated lattice constants agree with the experiment within a mean absolute percentage error of 1.4 percent. Semilocal functionals, such as the generalized gradient approximation (GGA) of Perdew, Burke, and Ernzerhof (PBE) and the strongly constrained and appropriately normed (SCAN) functional, fail to provide accurate bulk moduli, which indicates their inability to describe the system in a stretched or compressed state with respect to the equilibrium geometry. The PBE, PBE revised for solids, and revised Tao-Perdew-Staroverov-Scuseria functionals by Perdew et al predict too-low formation energies, while the SCAN slightly overestimates it. The inclusion of thermal correction or the long-range dispersion provides a negligible contribution to the formation energies estimated with semilocal density functional theory. The spin-orbit coupling improves the formation energies of PBE only by 7-8 meV, while it intensifies the overestimation of SCAN. We found that the nonlocality present in RPA is able to describe the transition between two delocalized electron densities (bulk elemental constituents to crystallized alloys), as required to provide accurate formation energies without any further corrections. Based on our results, we conclude that it is difficult to find a universal density functional which can give accurate results for a wide range of properties of intermetallic alloys. However, RPA can capture different bonding situations, often better than other density functionals. It gives accurate results for a wide range of ground-state properties for the alloys, generated from metals with completely filled d shells.
10.1103-PhysRevB.102.155422	-1		The surface atomic and electronic structure after deposition of one-third of a monolayer Te on Cu(111) was determined using a combination of low-energy electron diffraction (LEED), scanning tunneling microscopy and spectroscopy (STM/STS), angle-resolved single and two-photon photoelectron spectroscopy (ARPES/AR-2PPE), and density functional theory (DFT) calculations. Contrary to the current state in literature, Te does not create a two-dimensional surface alloy but forms Cu2Te2 adsorbate chains in a (2 root 3 x root 3)R30 degrees superstructure. We establish this by a high-precision LEED-IV structural analysis with Pendry R factor of R = 0.099 and corroborating DFT and STM results. The electronic structure of the surface phase is dominated by an anisotropic downward dispersing state at the Fermi energy E-F and a more isotropic upward dispersing unoccupied state at E-E-F = +1.43 eV. Both states coexist with bulk states of the projected band structure, and are therefore surface resonances.
10.1103-PhysRevB.111.144107	13	clusters; atomic; glass; atoms; composition; dynamics; metallic; icosahedral; glasses; simulations; molecular; cu-zr; molecular dynamics; metallic glasses; structural	First-principles based molecular-dynamics simulations have been performed for binary CuxTi1-x (x = 0.31, 0.50, and 0.76) alloys to investigate the relationship between local structure and dynamical properties in the liquid and undercooled melt. The undercooled melts show a pronounced short-range order, majorly a fivefold symmetry (FFS) around the Cu atoms, which competes with bcc ordering. This complex SRO is also reflected in the partial coordination numbers, where mainly a Z12 coordination is present around Cu, which corresponds to an icosahedral ordering. Higher coordination numbers were obtained for Ti compatible with Frank-Kasper polyhedra. The increasing Frank-Kasper polyhedra coordination scenario around Ti impacts the interatomic distances of Ti atoms, which increase with increasing Ti content. The Cu50Ti50 composition exhibits the highest FFS ordering and amount of Frank-Kasper polyhedra, which explains the slowest melt dynamics, found experimentally and in simulations for this composition. Thus, our results suggest that the high undercooling degree originates from the high complexity of the local structure rather than due to the preferred formation of Cu-Ti pairs, as Cu-Ti interactions were found to be weak.
10.1103-PhysRevB.63.174107	-1		The Cu-Pd phase diagram shows two Low-temperature ordered phases corresponding to B2 and L1(2) superlattices or, regardless of the site occupation, to bcc and fee geometrical arrangements. We show how the phase equilibria between these intermetallic compounds can be understood by introducing a hypothetical bce random-alloy phase and a three-step transformation from B2 to random bce to random fee to γ′. The two order-disorder transformations, B2 to random bcc and random fcc to L1(2), analyzed in the framework of the concentration wave-functional theory, appear to be ruled by the sires of the relevant Fermi surface (FS) nesting vectors in the two random-alloy systems. The transformation between the bce and fee solid solution phase is studied by first-principles Korringa-Kohn-Rostoker and coherent-potential approximation calculations, and it is shown to be influenced by electronic topological transitions occurring in the same systems. Our analysis points out the preeminent role played by the lattice-incommensurate FS nesting vectors that in both the random-alloy systems, give rise to frustrated concentration waves. The location of the B2-L 1(2) coexistence at T = 0 appears to be determined by the condition that the concentration waves of the fcc and bce random alloys are equally frustrated.
10.1103-PhysRevB.64.144420	-1		The anhysteretic magnetization of the granular metallic alloy Cu90Co10 is experimentally studied over a wide temperature range (2-700 K). The measurements definitely exclude that this alloy is a simple superparamagnet, even in the high-temperature limit, although some features of granular systems [such as the typical Langevin-like form of the anhysteretic magnetization curves M(H)] are often taken as evidence of superparamagnetism. A phenomenological theory is proposed, explicitly considering that particle moments interact through long-ranged dipolar random forces, whose effect is pictured in terms of a temperature T*, adding to the actual temperature T in the denominator of the Langevin function argument. This simple formula explains all features of the experimental M(H) curves. The theory indicates that the actual magnetic moments on interacting Co particles are systematically larger than those obtained fitting the magnetic data to a conventional Langevin function. The Cu90Co10 granular alloy is therefore identified as an interacting superparamagnet ISR The ISP regime appears as separating the high-temperature, conventional superparamagnetic phase from the low-temperature, blocked-particle regime. In this way, a magnetic-regime diagram can be drawn for each granular system. The competition between single-particle and collective blocking mechanisms is briefly analyzed. The proposed interpretation is thought to be applicable to other fine particle systems; its main features and intrinsic limits are discussed.
10.1103-PhysRevB.65.064201	-1		We combine the first-principles, Korringa-Kohn-Rostoker coherent potential approximation based calculations of compositional fluctuations with a statistical mechanical ring approximation to study the temperature (T) and composition (c) dependence of the atomic short-range order (SRO) in disordered, face-centred cubic, Cu-Pd alloys. The fourfold splitting of SRO peaks around the equivalent X(0,1,0) points in reciprocal space is obtained in a wide T-c region. Such splitting is shown to be an energy effect caused by the absolute minima of the Fourier transform of the effective atomic interactions and related previously to the existence of nested sheets of the disordered alloy's Fermi surface. However, we find that the T dependence of the SRO peak position is mostly an entropy effect. Both the calculated T and c dependences of the SRO peaks position are in good correspondence with the experimental data. The real-space effective atomic interactions and SRO parameters indicate the tendency for longer-period structures with increasing Pd concentration, as observed.
10.1103-PhysRevB.66.054428	4	transformation; martensite; martensitic; phase; shape; beta; memory; shape memory; temperature; temperatures; martensitic transformation; gamma; transformation temperatures; effect; thermal	We have studied the effect of ageing within the miscibility gap on the electric, magnetic, and thermodynamic properties of a nonstoichiometric Heusler Cu-Al-Mn shape-memory alloy, which undergoes a martensitic transition from a bcc-based structure (beta phase) towards a close-packed structure (M phase). Negative magnetoresistance that shows an almost linear dependence on the square of magnetization with different slopes in the M and beta phases was observed. This magnetoresistive effect has been associated with the existence of Mn-rich clusters with the Cu2AlMn structure. The effect of an applied magnetic field on the martensitic transition has also been studied. The entropy change between the beta and M phases shows negligible dependence on the magnetic field, but it decreases significantly with annealing time within the miscibility gap. Such a decrease is due to the increasing amount of Cu2MnAl-rich domains that do not transform martensitically.
10.1103-PhysRevB.66.085404	-1		The microstructural evolution and thermal properties of nanocrystalline (nc) Cu during mechanical attrition were investigated by using quantitative x-ray-diffraction and thermal analysis techniques. Upon milling of the Cu powders with coarse grains, the grain sizes are found to decrease gradually with the milling time, and remain unchanged at a steady-state value (about 11 nm) with continued milling. The microstrain and the stored enthalpy increase to maximum values during the grain refinement, and decrease then increase to the second maxima and decrease again within the milling stage of steady-state grain size, while the lattice parameter remains unchanged during the entire milling process. The grain boundary (GB) enthalpy of the nc Cu was estimated, showing a GB softening-hardening-softening cyclic variation within the steady-state milling. The present work indicated with clear experimental evidence that even within the milling stage of steady-state grain size, the microstructure (both the GB's and the crystallites) of nc materials is still changing, which may result from the GB sliding.
10.1103-PhysRevB.67.153401	-1		We use medium-energy ion scattering to determine the composition of each of the topmost three atomic layers of a single crystal of copper coated with an epitaxial submonolayer of nickel as a function of anneal temperature in the range 140-420 K. The technique confers layer and elemental resolution even though the constituents are adjacent in the Periodic Table. At a transition temperature of around 300 K, subsurface copper and surface nickel interchange so that the nickel comes to reside almost exclusively in the subsurface layer, and the top layer of the crystal becomes almost purely copper. Implications of the result for magnetic measurements are briefly sketched.
10.1103-PhysRevB.69.092202	-1		Crystallization of a Cu60Zr20Hf10Ti10 bulk metallic glass in the entire supercooled liquid region (SLR) is studied using an in situ x-ray diffraction with synchrotron radiation under high pressure and a differential scanning calorimeter at ambient pressure. The temperature-time-transition diagrams under ambient and high pressure are determined and compared, and the phase evolution of the crystallization with time is in situ exhibited under high pressure. We find that the crystallization in the temperature regime near glass transition temperature and near melting temperature in SLR cannot be described by a single crystallization mechanism in the entire SLR under high pressure. The effects of pressure on the crystallization of the BMG are explored.
10.1103-PhysRevB.69.144205	-1		We have obtained effective medium theory interatomic potential parameters suitable for studying Cu-Mg metallic glasses. We present thermodynamic and structural results from simulations of such glasses over a range of compositions. We have produced low-temperature configurations by cooling from the melt at as slow a rate as practical, using constant temperature and pressure molecular dynamics. During the cooling process we have carried out thermodynamic analyses based on the temperature dependence of the enthalpy and its derivative, the specific heat, from which the glass transition temperature may be determined. We have also carried out structural analyses using the radial distribution function (RDF) and common neighbor analysis (CNA). Our analysis suggests that the splitting of the second peak, commonly associated with metallic glasses, in fact, has little to do with the glass transition itself, but is simply a consequence of the narrowing of peaks associated with structural features present in the liquid state. In fact, the splitting temperature for the Cu-Cu RDF is well above T-g. The CNA also highlights a strong similarity between the structure of the intermetallic alloys and the amorphous alloys of similar composition. We have also investigated the diffusivity in the supercooled regime. Its temperature dependence indicates fragile-liquid behavior, typical of binary metallic glasses. On the other hand, the relatively low specific-heat jump of around 1.5k(B)/atom indicates apparent strong-liquid behavior, but this can be explained by the width of the transition due to the high cooling rates.
10.1103-PhysRevB.70.075106	-1		We have measured high resolution Compton scattering profiles for momentum transfer along a series of 28 independent directions from Cu0.842Al0.158 disordered alloy single crystals with normals to the surfaces oriented along the [100], [110], and [111] directions. The experimental spectra are interpreted via parallel first-principles KKR-CPA (Korringa-Kohn-Rostoker coherent-potential approximation) computations of these directional profiles. The Fermi surface determined by inverting the Compton data is found to be in good agreement with the KKR-CPA predictions. An electron diffraction study of the present Cu0.842Al0.158 sample is additionally undertaken to gain insight into short-range ordering effects. The scattering pattern displays not only the familiar diffuse scattering peaks, but also shows the presence of weak streaks interconnecting the four diffuse scattering spots around the (110) reciprocal lattice points. This study provides a comprehensive picture of the evolution of the shape of the Fermi surface of Cu with the addition of Al. Our results are consistent with the notion that Fermi surface nesting is an important factor in driving short-range ordering effects in disordered alloys.
10.1103-PhysRevB.70.134202	-1		For the immiscible Cu-Ta system, a Finnis-Sinclair potential is constructed and proven to be realistic in reproducing some static properties of the system. Applying the potential, molecular dynamics simulations reveal that among the nine Cu/Ta interfaces stacked by possible combinations of the (100), (110), and (111) atomic planes, the Ta (110) plane could remain stable up to a temperature of 600 degreesC, while the Cu (111) plane could remain unchanged only if combined with the Ta (100) and (110) planes. Simulations also show that for the other Cu/Ta interfaces, the interface energy serves as the driving force for interdiffusion of the Cu and Ta atoms across the interface, resulting in solid-state amorphization. Interestingly, it is calculated that the amorphization energy of Cu is smaller than that of Ta, thus resulting in an asymmetric growth behavior of the amorphous interlayer, i.e., amorphization of the Cu lattice is easier and faster than that of the Ta lattice. In general, the agreement between the simulation results and experimental observations is fairly good.
10.1103-PhysRevB.73.085403	-1		Kinetic Monte Carlo simulations are performed to study the evolution of interfaces in a model alloy system whose parameters are chosen so as to reproduce the main features of the Cu-Ni system, in particular the asymmetry of diffusion coefficients. Recently, Erdelyi [Phys. Rev. Lett. 89, 165901 (2002)] have shown that, in alloy systems forming ideal solid solutions, a large asymmetry can lead to the unexpected transient sharpening of interfaces that were initially flat and diffuse. In the present work we first remove two simplifications made by these authors and we study the consequences on the sharpening and broadening of interfaces during the annealing of a multilayered sample. First, in our diffusion model, atoms migrate by vacancy-assisted jumps instead of direct atom exchanges. Second, we investigate the effect of the initial roughness of interfaces on their evolution during annealing. In addition, we also study the influence of the short-range order that arises from a nonideal solid solution, since the Cu-Ni phase diagram displays a miscibility gap at low temperatures. While we observe that the transient sharpening phenomenon can still take place with a vacancy mechanism in alloys with large diffusional asymmetries, we find that the sharpening amplitude is reduced when short-range order is present and even suppressed when interfaces are initially rough . In the latter case, the in-plane wavelength of the roughness plays a determinant role and we identify a crossover from sharpening to broadening when this wavelength exceeds a threshold value. The practical implications of these effects are discussed.
10.1103-PhysRevB.73.224101	4	transformation; martensite; martensitic; phase; shape; beta; memory; shape memory; temperature; temperatures; martensitic transformation; gamma; transformation temperatures; effect; thermal	The high mobility of austenite-martensite interfaces is a characteristic of a thermoelastic martensitic transformation. Internal friction and elastic constants are very suitable probes to analyze this mobility. In this work, resonant ultrasound spectroscopy, differential scanning calorimetry, and neutron powder diffraction have been employed to analyze the role of defects in a first-order transformation. An anomalous behavior associated with the martensitic transformation in a Cu-Al-Ni shape-memory alloy has been observed; the internal friction peak measured during cooling completely disappears on heating. The elastic constants also show different behavior on heating and cooling. The different mobility of defects in the two phases, and the simultaneous occurrence of both the defect recovery processes and the martensitic transformation in the same temperature range, are the origin of the observed behavior. These effects show an exceptional influence of defects on thermoelastic equilibrium during a first-order structural transition. The proposed mechanism is general and may apply to other transitions than the one reported in this paper.
10.1103-physRevB.74.155416	-1		First-principles calculations of the Sigma 5(310)[001] symmetric tilt grain boundary in Cu with Bi, Na, and Ag substitutional impurities provide evidence that in the phenomenon of Bi embrittlement of Cu grain boundaries electronic effects do not play a major role; on the contrary, the embrittlement is mostly a structural or size effect. Na is predicted to be nearly as good an embrittler as Bi, whereas Ag does not embrittle the boundary in agreement with experiment. While we reject the prevailing view that electronic effects (i.e., charge transfer) are responsible for embrittlement, we do not exclude the role of chemistry. However, numerical results show a striking equivalence between the alkali metal Na and the semimetal Bi, small differences being accounted for by their contrasting size and softness (defined here). In order to separate structural and chemical effects unambiguously if not uniquely, we model the embrittlement process by taking the system of grain boundary and free surfaces through a sequence of precisely defined gedanken processes; each of these representing a putative mechanism. We thereby identify three mechanisms of embrittlement by substitutional impurities, two of which survive in the case of embrittlement or cohesion enhancement by interstitials. Two of the three are purely structural and the third contains both structural and chemical elements that by their very nature cannot be further unraveled. We are able to take the systems we study through each of these stages by explicit computer simulations and assess the contribution of each to the net reduction in intergranular cohesion. The conclusion we reach is that embrittlement by both Bi and Na is almost exclusively structural in origin; that is, the embrittlement is a size effect.
10.1103-PhysRevB.75.064304	-1		We report a comparison of the specific-heat measurements on isoelectronic Cu-Zn-Al shape-memory alloys in the parent cubic phase (L2(1)) and in the close-packed martensitic phase (18R). Measurements were made by thermal-relaxation calorimetry over the temperature range 1.9 <= T <= 300 K. For the close-packed martensitic phase we find that the specific heat behaves similarly to that of pure copper which is also close packed. However, we observe deviations from Debye behavior for the cubic phase at low temperatures. This deviation is accounted for by the addition of similar to 5% of Einstein localized modes to the Debye modes. Although the microscopic origin remains unknown, it was anticipated that it is related to the well-known softening of the TA(2)[110] phonon branch . In order to address this hypothesis an analysis of the lattice heat capacity of the cubic phase was compared to the calculated lattice heat capacity of beta-brass, as determined by integrating over the phonon density of states. A similar comparison was made between the close-packed phase and alpha-brass.
10.1103-PhysRevB.76.104206	-1		Low-temperature elastic constant C-ij(T) measurements for Cu60Zr30Ti10 and Cu60Hf25Ti15 bulk metallic glasses (BMGs) have been carried out to clarify their acoustic properties including a nonlinear interaction term. The BMGs show remarkably low shear to bulk modulus ratio C-44/B or equivalently high Poisson's ratio nu compared with the corresponding crystalline states. The C-ij(T) behaviors are well described by Varshni's formula [Phys. Rev. B 2, 3952 (1970)] and estimated Einstein temperatures suggested significant softening in the transverse-mode acoustic phonon. Mean Gruneisen parameters gamma derived from dB/dT slopes become almost identical with those of crystalline Cu. Our theoretical analysis based on inhomogeneous microstructure model successively explains the elastic constants and characteristic features of the BMGs within a framework of quasiharmonic thermodynamics, suggesting that microstructural inhomogeneity plays a dominant role in the BMGs.
10.1103-PhysRevB.77.144202	-1		Diffuse x-ray scattering of a Cu-17.2 at. % Mn single crystal, which was aged at 483 K for 2 weeks, was taken at three energies, namely, 6526, 8969, and 8909 eV, which were suited for an evaluation by the 3 lambda technique. The values of the species-dependent static atomic displacements closely agree with those of a Georgopoulos-Cohen evaluation, which also uses the three data sets. Nearest-neighbor displacements are dominant and with similar to 0.038 A largest among Cu-Mn pairs. A tendency is noted for lattice expansion between those elements (equal or unequal pairs) that are preferred in site occupancy over a random arrangement because of local atomic order.
10.1103-PhysRevB.77.165413	-1		Using first principles electronic structure methods, we calculate the effects of boron impurities in bulk copper and at surfaces and grain boundaries. We find that boron segregation to the Sigma 5(310)[001] grain boundary should strengthen the boundary up to 1.5 ML coverage (15.24 at./nm(2)). The maximal effect is observed at 0.5 ML and corresponds to boron atoms filling exclusively grain boundary interstices. In copper bulk, B causes significant distortion both in interstitial and regular lattice sites, for which boron atoms are either too big or too small. The distortion is compensated to a large extent when the interstitial and substitutional boron combine together to form a strongly bound dumbbell. Our prediction is that bound boron impurities should appear in a sizable proportion if not dominate in most experimental conditions. A large discrepancy between calculated heats of solution and experimental terminal solubility of B in Cu is found, indicating either a significant failure of the density functional approach or, more likely, strongly overestimated solubility limits in the existing B-Cu phase diagram.
10.1103-PhysRevB.79.014111	-1		According to models based on continuum elasticity, strain in a coherent multilayer has a polynomial dependence with the local composition. By performing atomistic calculations within a tight-binding potential, we show that composition gradients also affect the coherency strain in Cu-Ni multilayers having a modulation length in the nanometer range. This additional dependence is due to the presence of interfacial relaxation in these metallic systems. A Fourier analysis of the strain resulting from (100) sinusoidal composition multilayers allows us to identify the main missing terms in the continuum models that account for these composition gradient effects. Beyond this fundamental finding, we discuss how the derived extended model should be useful to extract both composition and strain fields from an x-ray scattering experiment on such multilayers.
10.1103-PhysRevB.79.214202	7	irradiation; shear; grain; ta; deformation; size; radiation; voids; nanocrystalline; simulations; similar; void; temperature; irradiated; boundaries	Twinning is one of most prevalent deformation mechanisms in materials. Having established a quantitative theory to predict onset twinning stress tau(crit) in fcc elemental metals from their generalized planar-fault-energy (GPFE) surface, we exemplify its use in alloys where the Suzuki effect (i.e., solute energetically favors residing at and near planar faults) is operative; specifically, we apply it in Cu-xAl (x is 0, 5, and 8.3 at. %) in comparison with experimental data. We compute the GPFE via density-functional theory, and we predict the solute dependence of the GPFE and tau(crit), in agreement with measured values. We show that tau(crit) correlates monotonically with the unstable twin fault energies (the barriers to twin nucleation) rather than the stable intrinsic stacking-fault energies typically suggested. We correlate the twinning behavior and electronic structure with changes in solute content and proximity to the fault planes through charge-density redistribution at the fault and changes to the layer- and site-resolved density of states, where increased bonding charge correlates with decrease in fault energies and tau(crit).
10.1103-PhysRevB.79.235427	-1		A direct and real-space study of the surface electronic structure on Cu-9 at. % Al(111) alloy surfaces was performed using low-temperature scanning tunneling microscopy. The standing waves on Cu-9 at. % Al(111)-(1X1) and (root 3X root 3)R30 degrees surfaces, which were obtained by controlling annealing temperature, were observed by differential-conductance mapping. Surface imperfection caused by segregation of aluminum atoms acted as static scattering centers in order to sustain the standing-wave formation. An analysis of the standing waves revealed a significant downward energy shift of the Shockley surface states on both surfaces. This shift is explained in terms of the strong redistribution of the surface electrons.
10.1103-PhysRevB.85.174201	-1		Using molecular dynamics simulations, we studied the short-time dynamics of the amorphous Cu50Zr50 alloy. We determined the occurrence of a well-defined boson peak in agreement with experimental observations. Our results indicate that the structural origin of the boson peak can be related to Cu and Zr atoms having large mean-square amplitudes in low-density defective local structures. Moreover, we show that these structural motifs display quasilocalized modes that resonantly couple with transverse phonons, leading to the accumulation of the low-energy modes around the boson peak. Finally, the correlation between the attenuation of sound and the boson peak is discussed.
10.1103-PhysRevB.91.180201	-1		Icosahedral short-range order (ISRO) has been widely accepted to be dominant in Cu-Zr metallic glasses (MGs). However, the diffusion mechanism and correlation of ISRO and medium-range order (MRO) to diffusion in MGs remain largely unexplored. Here, we perform a long time annealing up to 1.8 mu s in molecular dynamics simulations to study the diffusion mechanism and the relationship between atomic structures and the diffusion path in a Cu64.5Zr35.5 MG. It is found that most of the diffusing events performed by the diffusing atoms are outside ISRO and the Bergman-type MRO. The long-range diffusion in MGs is highly heterogeneous, via collective diffusing events through the liquidlike channels in the glass. Our results clearly demonstrate a strong correlation between the atomic structures and transport in MGs.
10.1103-PhysRevB.94.024102	4	transformation; martensite; martensitic; phase; shape; beta; memory; shape memory; temperature; temperatures; martensitic transformation; gamma; transformation temperatures; effect; thermal	We studied the two-step martensitic transition of a Cu-Al-Ni shape-memory alloy by calorimetry, acoustic emission (AE), and resonant ultrasound spectroscopy (RUS) measurements. The transition occurs under cooling from the cubic (beta, Fm3m) parent phase near 242 K to a mixture of orthorhombic 2H and monoclinic 18R phases. Heating leads first to the back transformation of small 18R domains to beta and/or 2H near 255 K, and then to the transformation 2H to beta near 280 K. The total transformation enthalpy is Delta H-T = 328 +/- 10 J/mol and is observed as one large latent heat peak under cooling. The back-transformation entropy under heating breaks down into a large component 18R to beta at 255 K and a smaller, smeared component of the transformation 2H to beta near 280 K. The proportions inside the phase mixture depend on the thermal history of the sample. The elastic response of the sample is dominated by large elastic softening during cooling. The weakening of the elastic shear modulus shows a peak at 242 K, which is typical for the formation of complex microstructures. Cooling the sample further leads to additional changes of the microstructure and domain wall freezing, which is seen by gradual elastic hardening and increasing damping of the RUS signal. Heating from 220 K to room temperature leads to elastic anomalies due to the initial transformation, which is now shifted to high temperatures. The transition is smeared over a wider temperature interval and shows strong elastic damping. The shear modulus of the cubic phase is recovered at 280 K. The phase transformation leads to avalanches, which were recorded by AE and by time-resolved calorimetry. The cooling transition shows very extended avalanche signals in calorimetry with power-law distributions. Cooling and heating runs show AE signals over a large temperature interval above 260 K. Splitting the transformation into two martensite phases leads to power-law exponents epsilon similar to 2 (beta <-> 18R) and epsilon similar to 1.5 (beta <-> 2H) while the phase mixture shows an effective AE exponent of 1.7.
10.1103-PhysRevE.90.052403	13	clusters; atomic; glass; atoms; composition; dynamics; metallic; icosahedral; glasses; simulations; molecular; cu-zr; molecular dynamics; metallic glasses; structural	Helmholtz free energies of the dominant binary crystalline solids found in the Cu-Zr system at high temperatures close to the melting curve are calculated. Our theoretical approach combines fundamental measure density functional theory (applied to the hard-sphere reference system) and a perturbative approach to include the attractive interactions. The studied crystalline solids are Cu(fcc), Cu51Zr14(beta), CuZr(B2), CuZr2(C11b), Zr(hcp), and Zr(bcc). The calculated Helmholtz free energies of crystalline solids are in good agreement with results from molecular-dynamics (MD) simulations. Using the same perturbation approach, the liquid phase free energies are calculated as a function of composition and temperature, from which the melting curve of the entire composition range of this system can be obtained. Phase diagrams are determined in this way for two leading embedded atom method potentials, and the results are compared with experimental data. Theoretical melting temperatures are compared both with experimental values and with values obtained directly from MD simulations at several compositions.
10.1103-PhysRevLett.106.085504	4	transformation; martensite; martensitic; phase; shape; beta; memory; shape memory; temperature; temperatures; martensitic transformation; gamma; transformation temperatures; effect; thermal	We propose a nonlocal continuum model to describe the size-dependent superelastic effect observed in recent experiments of single crystal Cu-Al-Ni shape memory alloys. The model introduces two length scales, one in the free energy and one in the dissipation, which account for the size-dependent hardening and dissipation in the loading and unloading response of micro-and nanopillars subject to compression tests. The information provided by the model suggests that the size dependence observed in the dissipation is likely to be associated with a nonuniform evolution of the distribution of the austenitic and martensitic phases during the loading cycle.
10.1103-PhysRevLett.115.165501	7	irradiation; shear; grain; ta; deformation; size; radiation; voids; nanocrystalline; simulations; similar; void; temperature; irradiated; boundaries	Indications of the Cu2Zr Laves phase are observed in MD simulations of amorphous Cu64Zr36 upon isothermal holding just above the glass transition temperature. The structural evolution towards Cu2Zr is accompanied by an increase in the fraction of Cu-centered icosahedra, which demonstrates that a large icosahedral fraction does not just indicate structural relaxation. The crystal-like regions generate an increase in strength and Young's modulus, and a stronger localized shear band. A universal relation between the fraction of full icosahedra and their interconnectivity is found, and both can be modified simultaneously via changes of temperature or strain.
10.1103-PhysRevLett.117.215501	7	irradiation; shear; grain; ta; deformation; size; radiation; voids; nanocrystalline; simulations; similar; void; temperature; irradiated; boundaries	Helium bubbles are one of the typical radiation microstructures in metals and alloys, significantly influencing their deformation behavior. However, the dynamic evolution of helium bubbles under straining is less explored so far. Here, by using in situ micromechanical testing inside a transmission electron microscope, we discover that the helium bubble not only can coalesce with adjacent bubbles, but also can split into several nanoscale bubbles under tension. Alignment of the splittings along a slip line can create a bubble-free channel, which appears softer, promotes shear localization, and accelerates the failure in the shearing-off mode. Detailed analyses unveil that the unexpected bubble fragmentation is mediated by the combination of dislocation cutting and internal surface diffusion, which is an alternative microdamage mechanism of helium irradiated copper besides the bubble coalescence.
10.1103-PhysRevLett.89.215502	-1		In a recent paper we used a phase-field model of solidification in deeply undercooled pure melts to show that a kinetic instability could result in dendrite tip splitting, and we speculated that such tip splitting could give rise to the phenomenon of spontaneous grain refinement. Here we present evidence, from the as-solidified microstructure of deeply undercooled ultrahigh purity Cu, of what appears to be dendrite tip splitting during recalescence. The significance of this finding in a nongrain refined sample is discussed in terms of the current theories for spontaneous grain refinement.
10.1103-PhysRevLett.92.245504	11	glass; bulk; metallic; bulk metallic; gfa; bmg; glassy; metallic glass; ability; bulk metallic glass; amorphous; addition; crystallization; mm; glass-forming	We report the unusual glass-forming ability (GFA) of a family of Cu-based alloys, Cu46Zr47-xAl7Yx (0
10.1103-physrevmaterials.1.070602	-1		Segregated impurities at grain boundaries can dramatically change the mechanical behavior of metals, while the mechanism is still obscure in some cases. Here, we suggest a unified approach to investigate segregation and its effects on the mechanical properties of polycrystalline alloys using the example of 3sp impurities (Mg, Al, Si, P, or S) at a special type Sigma 5(310)[001] tilt grain boundary in Cu. We show that for these impurities segregating to the grain boundary, the strain contribution to the work of grain boundary decohesion is small and that the chemical contribution correlates with the electronegativity difference between Cu and the impurity. The strain contribution to the work of dislocation emission is calculated to be negative, while the chemical contribution is calculated to be always positive. Both the strain and chemical contributions to the work of dislocation emission generally become weaker with the increasing electronegativity from Mg to S. By combining these contributions together, we find, in agreement with experimental observations, that a strong segregation of S can reduce the work of grain boundary separation below the work of dislocation emission, thus embrittling Cu, while such an embrittlement cannot be produced by a P segregation because it lowers the energy barrier for dislocation emission relatively more than for work separation.
10.1103-PhysRevMaterials.5.015402	-1		The ability to control carrier concentration based on the extent of Cu solubility in the Cu2xHg2-xGeTe4 alloy compound (where 0 <= x <= 1) makes Cu2xHg2-xGeTe4 an interesting case study in the field of thermoelectrics. While Cu clearly plays a role in this process, it is unknown exactly how Cu incorporates into the Cu2xHg2-xGeTe4 crystal structure and how this affects the carrier concentration. In this work, we use a combination of resonant energy x-ray diffraction (REXD) experiments and density functional theory (DFT) calculations to elucidate the nature of Cu incorporation into the Cu2xHg2-xGeTe4 structure. REXD across the Cu-k edge facilitates the characterization of Cu incorporation in the Cu2xHg2-xGeTe4 alloy and enables direct quantification of antisite defects. We find that Cu substitutes for Hg at a 2:1 ratio, wherein Cu annihilates a vacancy and swaps with a Hg atom. DFT calculations confirm this result and further indicate that the incorporation of Cu occurs preferentially on one of the z = 1/4 or z = 3/4 planes before filling the other plane. Furthermore, the amount of Cu-Hg antisite defects quantified by REXD was found to be directly proportional to the experimentally measured hole concentration, indicating that the Cu Hg defects are the driving force for tuning carrier concentration in the Cu2xHg2-xGeTe4 alloy. The link uncovered here between crystal structure, or more specifically antisite defects, and carrier concentration can be extended to similar cation-disordered material systems and will aid the development of improved thermoelectric and other functional materials through defect engineering.
10.1103-PhysRevMaterials.6.053403	13	clusters; atomic; glass; atoms; composition; dynamics; metallic; icosahedral; glasses; simulations; molecular; cu-zr; molecular dynamics; metallic glasses; structural	The composition and magnetic dependent interfacial energy in Cu-Co immiscible alloys is investigated within a coherent interface model using ab initio calculations. We translate the composition dependence of the interfacial energy to the temperature dependence considering the variations of the equilibrium compositions of precipitate and matrix with respect to temperature. The obtained results are in reasonable agreement with those obtained by experiments and thermodynamic calculations. Reviewing the experimental methods for determining the interfacial energy based on kinetic models for precipitate nucleation and coarsening, as well the thermodynamic models based on broken-bond models, we point out that the temperature effect on the interfacial energy in the above models is primarily due to the composition change of the interface. The present work emphasizes the effort to understand the meaning of the speciously same quantity in different methods.
10.1103-PhysRevMaterials.8.043602	13	clusters; atomic; glass; atoms; composition; dynamics; metallic; icosahedral; glasses; simulations; molecular; cu-zr; molecular dynamics; metallic glasses; structural	A general purpose machine -learning interatomic potential (MLIP) for the Cu-Zr system is presented based on the atomic cluster expansion formalism [R. Drautz, Phys. Rev. B 99 , 014104 (2019)]. By using an extensive set of Cu-Zr training data generated withdensity functional theory, this potential describes a wide range of properties of crystalline as well as amorphous phases within the whole compositional range. Therefore, the machine learning interatomic potential (MLIP) can reproduce the experimental phase diagram and amorphous structure with considerably improved accuracy. A massively different short-range order compared to classica interatomic potentials is found in glassy Cu-Zr samples, shedding light on the role of the full icosahedral motif in the material. Tensile tests of B2-CuZr inclusions in an Cu 50 Zr 50 amorphous matrix reveal the occurrence of martensitic phase transformations in this crystal -glass nanocomposite.
10.1103-ryzs-zzvf	7	irradiation; shear; grain; ta; deformation; size; radiation; voids; nanocrystalline; simulations; similar; void; temperature; irradiated; boundaries	Structural heterogeneity has been identified as a critical factor in determining the mechanical and thermodynamic properties of glasses. However, its influence on glass formation has not been fully understood. Here we report the nanometer-scale chemical heterogeneity of Ag in a ribbon Cu45Zr45Ag10 (at. %) metallic glass using Cs-corrected scanning transmission electron microscopy. Such heterogeneity is confirmed to occur in a Cu45Zr45Ag10 model glass when the cooling rate is tuned below <^>108 K/s, as demonstrated by a hybrid Monte Carlo molecular dynamics simulation. A structural survey of (Cu0.5Zr0.5)100-xAgx (where x ranges from 0 to 20) model glasses cooled at 106 K/s reveals an inverse relationship between the fraction of icosahedral-like short-range order and the fractal dimensionality of chemical heterogeneity. Our findings demonstrate a significant role of fractal heterogeneity in promoting glass formation, a quantitative factor that has not been adequately addressed in prevailing theories of glass formation.
10.1103-xn1s-28z3	-1		Properties of Cu-Ni solid solutions have long been studied in physical and materials sciences. Yet, their many-body properties have not been well understood. Here, we investigate ultrafast luminescence in near-infrared region for Cu1-xNix alloys. The luminescence intensity was the highest in Cu and decreased dramatically by adding Ni, approaching close to the value for pure Ni at x = 0.45. This composition dependence was well reproduced by calculations assuming two-body scattering of the energetic electrons. The luminescent decay rate was not straightforward, i.e., it decreased first by adding Ni up to x = 0.17 and then started to increase approaching twice the initial value at x = 0.45. This behavior was in good agreement with ab initio calculations of electron-phonon (e-ph) coupling strength . This work provides a new perspective on the electron relaxation dynamics in solid solution systems.
10.1107-S0021889801008809	-1		Single crystals of Cu-41.5 at% Ni-16 at% Fe have been studied by small-angle and large-angle X-ray scattering in order to determine the displacements induced by the disc-like precipitates formed during decomposition. The small-angle X-ray scattering (SAXS) patterns gave information on the size and the organization of the precipitates, while the scattering near Bragg peaks allows a determination of the distortions of the lattice created by these precipitates. The variations of the atomic scattering factors of Fe, Ni and Cu (for the large-angle measurements) were used to determine both the partial structure functions ('chemical' data) and the partial displacements. The precipitates were found to be enriched in Fe and Ni, which induced a contraction of the lattice, while the depleted matrix (mainly Cu) was dilated. This succession of compressed and dilated regions is very stable and prevents a single precipitate from growing much in this direction during coarsening. This can explain why a single precipitate tends to grow mainly in the orthogonal directions, where the extension of the displacements is smaller than the precipitated region.
10.1107-S0021889805006382	4	transformation; martensite; martensitic; phase; shape; beta; memory; shape memory; temperature; temperatures; martensitic transformation; gamma; transformation temperatures; effect; thermal	Single crystals of different Cu-Ni-Co and Cu-Ni-Fe alloys, forming spheroid or plate-like precipitates during decomposition, have been studied by small-angle (SAXS) and wide-angle X-ray scattering (WAXS). The SAXS patterns gave information on the sizes and the organization of the precipitates, while the scattering near Bragg peaks allowed a determination of the distortions of the lattice created by these precipitates. The variations of the SAXS spectra with the atomic scattering factors of Co ( or Fe) and Ni were used to determine the composition variation between matrix and precipitates (i.e. the 'chemical' term), while those of the WAXS spectra enabled the determination of the displacements in the matrix and in the precipitates. The precipitates were found to be enriched in respectively Co and Ni, or Fe and Ni, inducing a local contraction of the lattice, while the matrix ( mainly Cu) was of course depleted in the same elements, and its lattice was dilated. These precipitates are piled up along one of the three [100] 'soft' directions. The variations of the deformation field with the precipitate sizes ( along both directions parallel and orthogonal to the pile-up orientation), and with the distance between precipitates have been determined. From the knowledge of such variations, it was possible to modify the respective deformation fields in such a way that the respective precipitates have the same sizes, but with a different geometry, and then to isolate what was induced solely by the geometry of a precipitate. Moreover, these experiments yielded the determination of the secondary components of the displacement field ( displacements orthogonal to the pile-up direction), which were found to be weak compared with the primary one ( parallel to the same direction). Finally, from the variation of the aspect ratio of the precipitates with the aging duration, it was possible to estimate the surface energy of the precipitates, and a comparison between SAXS and WAXS results shows the applicability of this new approach to the decomposition process.
10.1107-S0021889897002197	-1		The decomposition kinetics of dilute Cu-Co alloys containing 0.5 at% Co were investigated by time-resolved anomalous small-angle X-ray scattering (ASAXS). No evidence for the existence of compositional fluctuations preceding the formation of Co precipitates was found. The separated scattering curves of the Co precipitates show 'self-similarity'. The results are interpreted in terms of a classical process of decomposition and values of 0.18 J m(-2) for the interfacial energy and 10.9 Angstrom for the critical radius are calculated.
10.1107-S0909049501000292	9	magnetic; magnetization; magnetoresistance; temperature; superparamagnetic; annealing; gmr; field; magnetic properties; ferromagnetic; granular; samples; magnetic field; melt-spun; particles	We have studied the structure of melt-spun copper-permalloy samples (Cu80Fe4Ni16), annealed at several temperatures up to 873 K by means of EXAFS spectroscopy. The results for iron first neighbor average distance showed a slow decrease for annealing temperatures higher than 673 K. The nickel first neighbor distance had almost no change in the whole temperature range. This behavior is discussed in the light of rich iron cluster formation, and is compared with magnetic measurement results.
10.1107-S090904950100067X	-1		Magnetic semiconductors such as CuxMg1-xO, which are perspective materials for high-temperature superconductivity have been studied by EXAFS. The new technique of obtaining information from EXAFS-data has been described. It is based on the special iterative algorithm of solving an inverse ill-posed problem on the determination the partial pair correlation functions (pPCFs). Bond lengths of the nearest neighbours have been determined. It was clearly shown that the short range order in compound Cu0.2Mg0.8O differs from a hypothetical alloy with MgO structure and from the copper oxide.
10.1107-S1600576714021232	-1		Samples of Cu47.5Zr47.5Al5 metallic glass were prepared at different cooling rate, R. The dependence of the X-ray diffraction patterns on R was analysed by comparing them with corresponding patterns of computer-simulated models generated at different cooling rates as well. The observed changes in the experimental diffraction patterns are reproduced by the simulations, showing an increasing fraction of icosahedral clusters with decreasing cooling rate. The difference of the fractions of icosahedrally coordinated atoms in mould-cast and rapidly quenched Cu47.5Zr47.5Al5 averages to 3 (1)%. Different frozen-in thermal displacements and different density are ruled out as a possible origin for the experimental observations.
10.1108-00035590910955531	2	corrosion; surface; film; electrochemical; films; spectroscopy; layer; current; solution; potential; resistance; composition; x-ray; ions; showed	Purpose-The purpose of this paper is to evaluate the effect of seawater temperature on the corrosion behaviour of 90-10 cupronickel alloys. Also, to investigate the effect of thiosulphate additions (one of the major sulphide oxidation products in seawater) on the alloy corrosion rate in seawater. Design/methodology/approach-Potentiodynamic polarization measurement (DC) was used to estimate the corrosion rate of the cupronickel alloy in seawater with and without thiosulphate species (50-650 ppm). Findings-It was observed that the cupronickel alloy suffered accelerated corrosion as the seawater temperature was raised from 25 to 50 or 80 degrees C. The increase in the corrosion rate was found to correspond well with the negative shift in the free corrosion potential. Thiosulphate addition was found to depend on the test temperature. At 25 degrees C, thiosulphate activated the alloy dissolution rate and the higher were the thiosulphate concentrations, the higher was the corrosion rate. At 50 or 80 degrees C, however, thiosulphate promoted the dissolution rate at early stages, but seemed to interfere with the surface film formation later on, producing a black film that effectively decreased the alloy corrosion rate. At higher potentials, however, the film became non-protective, leading to accelerated corrosion once again. Originality/value-This paper explains the corrosion behaviour of 90-10 cupronickel alloys in seawater as a function of test temperature and thiosulphate additions.
10.1108-03699420710749027	2	corrosion; surface; film; electrochemical; films; spectroscopy; layer; current; solution; potential; resistance; composition; x-ray; ions; showed	Purpose-To correlate the inhibitory effect of triazole compounds on the corrosion of copper in HCl at various temperatures by semi-empirical molecular orbital theory. Design/methodology/approach-Two triazoles were selected as the best inhibitors among the triazole compounds tested. Gravimetric and electrochemical measurements were conducted. Findings-Correlation between inhibition efficiency and calculation of molecular orbital of triazole compounds was obtained. Cu(I)-triazole complex formation was confirmed by UV spectroscopy. Research limitations/implications-The calculation of energetic levels of molecular orbital may be a tool to explain the classification of inhibitor efficiency. Practical implications-The theoretical calculation is a complementary mean to selecting an efficient inhibitor among a given series. Good agreement between the experimental methods explored and theoretical calculations was observed. Originality/value-The originality of this work was the finding of the correlation between energetic levels of orbital molecular and inhibitor efficiency of triazole compounds. The confirmation of the formation of Cu(I)-triazole by UV-visible spectroscopy was also new.
10.1108-ACMM-03-2025-3203	2	corrosion; surface; film; electrochemical; films; spectroscopy; layer; current; solution; potential; resistance; composition; x-ray; ions; showed	PurposeThis paper aims to clarify the photoelectrochemical effect of cuprite (as the main corrosion products of copper) on the corrosion of pristine copper.Design/methodology/approachA cuprite layer with p-type semiconductor characteristic was electrodeposited on pristine copper; the corrosion promotion effect of cuprite on copper under AM1.5 (100 mW/cm(2) simulated sunlight) illumination was determined via potentiodynamic polarization test.FindingsPhoto-induced electrons tend to transport to electrolyte side for the reduction of dissolved oxygen, whereas the holes are more apt to deprive the electrons by oxidizing the Cu atoms to CuI and CuII ions. Both the anodic and cathodic processes of Cu corrosion were enhanced under illumination, especially for the anodic process.Originality/valueA drawback of semi-logarithmic polarization curve for revealing the actual photo electrochemical effect on the corrosion characterization is proposed; a method of current subtraction at identical overpotential between the currents derived from illumination and darkness is proposed as well.
10.1108-ILT-03-2019-0106	17	wear; composites; coating; friction; composite; coatings; surface; tribological; properties; wear resistance; resistance; powder; sliding; matrix; wear rate	Purpose This paper aims to fabricate a FeS/Cu-Bi copper-based lead-free bearing material to maintain good friction-reducing and anti-adhesive properties under boundary lubrication conditions. Design/methodology/approach The materials were fabricated by mechanical alloying and powder metallurgy and tested under dry friction conditions using HDM-20 wear tester. Findings The results show that mechanical alloying can improve the antifriction and wear resistance of the materials. The 6 per cent FeS and 6 per cent Bi in the copper-based bearing materials fabricated by mechanical alloying have a better synergism which contributes to the friction and wear properties of copper matrix. Originality/value This new approach solves the problems of Bi and FeS mutual segmentation, mutual agglomeration and poor interface bonding.
10.1108-ILT-04-2023-0092	-1		Purpose-Low performance life and increased machine downtime due to wear of resistance welding copper electrode is of major concern in fin-tube resistance welding in waste heat recovery boilers. The purpose of this study is to investigate an alternative material with good wear resistance to replace the currently utilized C11000 electrolytic tough pitch (ETP) copper electrode. Design/methodology/approach-In this study, a Cu-Cr-Zr ternary alloy was developed for fin-to-tube welding electrode by melting commercial grade electrolytic copper (99.9% purity) plates, chips of chromium, powder of zirconium at 1100 degrees-1300 degrees C, followed by hot forging and precipitation hardening at 450 degrees-550 degrees C to attain appropriate grain flow. Microstructures of Cu-Cr-Zr alloys were analysed using scanning electron microscopy coupled with energy-dispersive backscatter electron spectrometry. Findings-Wear performance of Cu-Cr-Zr and C11000 ETP Cu was evaluated using pin-on-disc set-up with Taguchi's L-8 orthogonal array. Ranking of the parameters was done, and it was observed that the material and temperature play a very significant role in controlling the wear of an electrode. Practical implications-Rate of fin-tube resistance welding was increased by 26% with Cu-Cr-Zr alloy. Further investigation on effect of plasma on the metallurgical characteristics of Cu-Cr-Zr is recommended. Originality/value Tribo-mechanical performance of newly developed Cu-Cr-Zr ternary alloy was compared with C11000 ETP copper. Peer review-The peer review history for this article is available at: https://publons.com/publon/10.1108/ILT-04-2023-0092/
10.1108-ILT-06-2023-0174	-1		Purpose-The purpose of this paper is to investigate the friction and wear mechanisms in copper-based self-lubricating composites with MoS2 as the lubricating phase, which provides a theoretical basis for subsequent research on high-performance copper-based self-lubricating materials.Design/methodology/approach-Friction tests were performed at a speed of 100 r/min, a load of 10 N, a friction radius of 5 mm and a sliding speed of 30 min. Friction experiments were carried out at RT-500 degrees C. The phase composition of the samples was characterized by X-ray diffraction of Cu Ka radiation, and the microstructure, morphology and elemental distribution were characterized by scanning electron microscopy and energy dispersive spectroscopy. Reactants and valences formed during the wear process were analyzed by X-ray photoelectron spectroscopy.Findings-The addition of MoS2 can effectively improve friction-reducing and anti-wear action of the matrix, which is beneficial to form a lubricating film on the sliding track. After analyzing different changing mechanism of the sliding tracks, the oxides and sulfides of MoS2, MoO2, Cu2O, CuO and Ni(OH)(2) were detected to form a synergetic lubricating film on the sliding track, which is responsible for the excellent tribological properties from room to elevated temperature.Research limitations/implications-For self-lubrication Cu-Sn-Ni-MoS2 material in engineering field, there are still few available references on high-temperature application.Practical implications-This paper provides a theoretical basis for the following research on copper-based self-lubricating materials with high performance.Originality/value-With this statement, the authors hereby certify that the manuscript is the results of their own effort and ability. They have indicated all quotes, citations and references. Furthermore, the authors have not submitted any essay, paper or thesis with similar content elsewhere. No conflict of interest exits in the submission of this manuscript.
10.1108-RPJ-02-2016-0017	3	sma; shape; shape memory; memory; smas; superelastic; bars; damping; cu-al-mn; mechanical; bending; applications; numerical; sma bars; material	Purpose-The purpose of this paper is to explore the possibility of producing Cu-based shape memory alloys (SMA) by means of direct metal laser fabrication (DMLF). Design/methodology/approach-The fabrication approach consists of the combination of laser melting of a metallic powder with heating treatment in a controlled inert atmosphere. Three prospective Cu-Al-Ni alloy compositions were tested, and the effects of laser power, as well as laser exposure time, were verified. Findings-All the processed materials were found to attain microstructures and phase change transformation temperatures typical of this type of SMA. Originality/value-This work showed a proof of concept toward the development of DMLF-based additive manufacturing of near net shape components of Cu-based SMAs from elemental powders.
10.1108-RPJ-12-2020-0307	-1		Purpose In this research, the highly dense bulk Cu-5Sn alloy specimens were fabricated using selective laser melting (SLM). This study aims to establish the relationship between laser power (LP), scanning speed (SS) and hatch space (HS) with surface roughness (Ra) and density. To obtain Cu-5Sn alloy formed parts with high strength and low surface roughness. The microstructure and mechanical properties of SLMed Cu-5Sn were investigated. Design/methodology/approach The relative density (RD) was optimized using the response surface method (RSM) and analysis of variance. First, the Ra of SLMed formed specimens was studied to optimize the forming process parameters with a good surface. Then, the dense specimens were studied by ANOVA and the RSM to obtain dense specimens for mechanical property analysis. Findings Dense specimens were obtained by RSM and ANOVA. The tensile properties were compared with the casted specimens. The yield and ultimate strengths increased from 71 and 131 MPa for the cast specimens to 334 and 489 MPa for the SLMed specimens, respectively. The ductility increased significantly from 11% to 23%, due to the refined microstructure of the SLMed specimens, as well as the formation of many twin crystals. Originality/value The Ra, RD and mechanical properties of SLM specimens Cu-5Sn were systematically studied, and the influencing factors were analyzed together. This study provides a theoretical and practical example to improve the surface quality and RD.
10.1109-20.801003	9	magnetic; magnetization; magnetoresistance; temperature; superparamagnetic; annealing; gmr; field; magnetic properties; ferromagnetic; granular; samples; magnetic field; melt-spun; particles	Magnetic characteristics and structure of granular Cu90Co10 alloy were investigated in order to explain their relationship with electric transport properties, The annealed sample contains mainly Co-particles with sizes of few nanometers and some much larger particles or agglomerations, which are not superparamagnetic, It is shown that the ferromagnetic phase contribution to the total magnetization (calculated applying the new, invented method) and differentiated surface to volume ratio of superparamagnetic particles are the main sources of the observed deviation of the magnetoresistance characteristics from that expected theoretically for superparamagnetic particles of equal size.
10.1109-20.911834	-1		Current flow through the breech region of the rail conductor produces the longest exposure to Joule heating for any location in a simple electromagnetic launcher (EML) bore. Movement of a solid, stationary armature occurs when electromagnetic propulsion forces exceed frictional and mechanical loading forces imposed at start-up. Consequently, the armature dwells at this footprint for an extended thermal cycle longer than any subsequently traversed location. We report results of four copper alloy specimens (Be-Cu, Cu-Cr, Cu-W, DS Cu) placed as removable tiles near the breech of a medium caliber EML, Specimen performance in single or multiple launch tests is evaluated by strength, hardness, electrical and thermal conductivity properties, Muzzle voltage traces are used to fingerprint the electrical performance for peak currents exceeding 900 kA, The materials are evaluated by optical microscopy for changes in microstructure and hardness, and by optical profilometry for surface damage that could affect long term performance.
10.1109-77.828471	-1		The primary requirements of conductor wires used for pulsed magnets are high strength and high electrical conductivity. There are several methods available to produce these wires, albeit expensive. This paper presents a preliminary result of a manufacturing method, which incorporates the conventional drilled-billet technique. The project can be classified into two stages. In the first stage, a processing method was developed to optimize the strength of the primary Cu-Nb/Ti rods, which were used as inserts in drilled Cu billets. An assembly of the Cu billets and the primary Cu-Nb/Ti rods was made, and this was subsequently deformed by swaging, avoiding an extrusion process. The microstructure, mechanical properties and electrical conductivity of the wires were evaluated at various stages of the processing. Details of the processing and characterization techniques used are provided in this paper. Although, the processing resulted in a wire with a reasonable conductivity of 78.8 %IACS at room temperature, its tensile strength was low. The low tensile strength value was attributed to a lack of adequate bonding in the material. Improvement in the manufacturing process is currently being implemented, with the view to address the bonding issue.
10.1109-77.919773	-1		Fabrication of long-length, textured substrates constitute a critical step in the successful application of coated High Temperature Superconductors (HTS). Substrate materials stronger than nickel are needed for robust applications, while substrates with non-magnetic characteristics are preferred for AC applications The present work is thus focused on development of texture in high strength, non-magnetic substrate materials As the development of cube texture is easier in medium to high stacking fault energy materials, binary alloys based on nickel were evaluated for the present application. High purity alloys were melted and hot/cold worked to obtain thin tapes. The development of texture in these alloys as a function of processing parameters was studied by x-ray diffraction and metallographic technique. Orientation Imaging Microscopy (OIM) was used to quantify the extent of texture development in these substrates. Results to date on the development of texture by thermo-mechanical processing of these alloys are presented.
10.1109-ACCESS.2024.3408319	-1		The multimodal properties of the grinding wheel matrix significantly impact grinding performance, while research on the interactions among these properties remains notably limited. To investigate the latent relationship between the microstructure and the bending strength of the bronze matrix, a visual quantization model based on the microstructure of the Cu-Sn alloy samples was established. The proposed model integrated a image segmentation network module, a quantitative characterization module, and a multivariate prediction module. The enhancement of the segmentation network is based on the synergistic combination of full-scale feature fusion with attention mechanism. The quantitative characterization parameters of metallographic microstructure features are proposed, and the most prominent intercorrelation between these parameters is studied from multiple dimensions. The results show that the modified image segmentation network exhibits superior performance compared to Unet, as evidenced by a 3% increase in Mean Intersection over Union (MIOU). The optimized output strategy (eta Dd -PSO-SVR) can contribute to the model's prediction accuracy of material bending strength (MSE = 23.558,R-2=0.934$ ). Finally, this work shows that the microscopic information demonstrates great adaptability for the machine learning models in predicting bending strength .
10.1109-LMWC.2016.2537780	-1		We report on Cu/Ni paired superlattice conductors featuring reduced radio frequency (RF) loss based on eddy current cancelling (ECC). Also, the effects of the width and the individual layer thickness of the superlattice conductors have been studied for improved RF performance. The usage of Ni as the ferromagnetic material in the non-ferromagnetic/ferromagnetic superlattice structure is advantageous as it has a high contrast between the in-plane and out-of-plane magnetic coercivity fields making it suitable for effective thin film superlattice ECC, is abundant, and does not require a stoichiometric control of composition as other alloy magnetic materials do. Ni's negative permeability is also able to effectively cancel out the positive permeability of copper in the frequency of interest. A transmission line consisting of 10 superlatticeCu/Ni layers, with each layer being of 150 nm/25 nm totaling 1.75 mu m shows the same resistance value as one consisting of 10 Cu/Ni layers with each being 600 nm/100 nm totaling 7 mu m thick at 13 GHz, revealing 75% conductor volume reduction. Experimental results showmore than three times improvement in the figure of merit defined as frequency/effective resistivity, compared with other state-of-the-art devices.
10.1109-TASC.2007.898934	2	corrosion; surface; film; electrochemical; films; spectroscopy; layer; current; solution; potential; resistance; composition; x-ray; ions; showed	YBa2Cu3OX (YBCO) coated conductors have been fabricated on cube textured Cu or Cu-based alloy substrates using various buffer layers such as CeO2, ZrO2, etc. Fabrication of buffer layers on Cu substrates using surface-oxidation epitaxy (SOE) has the potential to reduce the process complexibility and make the coated conductor more cost effective. In this work, we fabricated cube textured Cu2O as a component buffer layer by thermal oxidation of cube textured Cu(200) substrates. A biaxially-aligned textured Cu2O layer was obtained for 1 min oxidation in air at 1000 degrees C. Texture analysis was performed using X-ray Diffraction (XRD) analysis. Microstructural characteristics of the layer were determined by scanning electron microscopy (SEM). The experimental results suggested that theCu(2)O can be a promising buffer layer for YBCO coated conductors from the viewpoint of the simplification of the process.
10.1109-TASC.2016.2529418	-1		Nb-rod-method Cu-Nb reinforced Nb3Sn (Cu-Nb/Nb3Sn) wires have been successfully developed for commercialization of the react-and-wind (R&W) processed Nb3Sn coils. Superconducting performance of the Cu-Nb/Nb3(S)n wires is improved by applying the prebending treatment at room temperature, because of releasing the residual stress of Nb3Sn filaments (prebending strain effects). The purpose of this study is to confirm the efficient use of the prebending strain effects for optimizing critical current (I-c) characteristics under pure bending strain on the R&W coil design. The Cu-Nb/Nb3Sn strands of 0.8-mm diameter were heat treated at 670 degrees C for 96 h on stainless steel grooved cylindrical holders of different radii of 10.1-32.1 mm. After half of the reacted strands were applied repeating prebending strain of +/- 0.5%, each of the prebent strands and the as-reacted (without prebending) strands was transferred to a Ti-6Al-4V alloy grooved cylindrical holder of 15.6-mm radius. Then, those Ic measurements were carried out under applied pure bending strains ranging from -0.9% to +0.84% at 11-17 T, 4.2 K. As a result, the prebent strand showed no deterioration of I-c in the applied pure bending strain ranging from -0.5% to +0.5% and had larger I-c than that of the as-reacted strand at no pure bending strain. In this paper, the I-c enhancements of the prebent Cu-Nb/Nb3Sn strands under pure bending strains are analyze d by using the I-c characteristics under axial strains.
10.1109-TASC.2019.2906781	5	materials; thermal; heat; properties; material; welding; sintering; fusion; strength; laser; heat sink; thermal conductivity; mechanical; sink; manufacturing	High-strength copper conductor composites have been used in pulse magnet applications and as internal reinforcement in superconductor wires. The required property is high strength while maintaining high conductivity. Heavily worked pure copper has a strength of 450-500 MPa. Increasing the strength of copper by alloying additions without affecting the conductivity drastically is a significant challenge. Mixing pure copper with a higher modulus, higher strength tantalum alloys is an option to meet the challenge. This work reports on the use of a tantalum-tungsten alloy to strengthen high-purity copper through a multi-filament approach . The tantalum tungsten has a high modulus and very low solubility in copper. A composite wire containing 133 filaments of Ta-W (25% by volume) has a conductivity of 80% International Annealed Copper Standard and ultimate tensile strength of over 650 MPa with a modulus over 140 GPa. The wire has good ductility and toughness. These results are comparable or better than current options, and the potential to improve this product is explored.
10.1109-TASC.2022.3166712	-1		High field resistive magnets use Cu matrix composites as conductors because composite conductors have high mechanical strength . The conductors are manufactured by cold deformation and heat treatment that introduce refined obstacle distance to resist dislocation motions. The increased density of these obstacles increases the mechanical strength of the conductors. Under cyclic loading, such as the loading condition in pulsed resistive magnets, the conductors may soften or harden depending on the interaction of the obstacles with the dislocations evolved during the loading. Understanding and predicting the performance of the conductors under cyclic loading help researchers to predict the life of the coils made from these conductors, to make efficient use of them in magnets, and to manufacture conductors to meet the requirements of the magnets, particularly when the magnetic stress is above the yield strength of the conductors. The goal of this research is to understand the fatigue properties of two composite conductors and to relate such properties to types of obstacles. The fatigue test loading is in displacement-controlled mode, which is like what occurs in a state-of-the-art pulsed magnet. This work sheds a light on the correlation between the tensile and fatigue properties in composite conductors by consideration of types of obstacle in composite conductors.
10.1109-TASC.2024.3520085	-1		With the development of Chinese medical industry, medical proton therapy instrument accelerator magnets were gradually developed to miniaturization, which puts forward high requirements for the performance of low loss NbTi superconducting wires. A new experimental structure of high critical current density and low loss NbTi/Cu0.5Mn/Cu superconducting wire has been developed in this paper. The microstructure and hardness of high purity oxygen-free copper and Cu-0.5%Mn alloy were characterized, and the resistivity at 300 K, 10 K and 4.2 K were compared. The resistivity of Cu-0.5%Mn alloy at 300 K, 10 K and 4.2 K is 3.8 mu Omega center dot cm, 2.2 mu Omega center dot cm and 2.2 mu Omega center dot cm. The residual resistance ratio is only 1.7. The Cu-0.5%Mn alloy has a large resistance at low temperature, which could prevent the coupling between NbTi filament effectively. The experimental wire of Phi 0.8 mm and 44 064 filaments was successfully prepared by a double stacking method. The filaments of the wire were uniformly deformed and the diameter of the filament was only 2.5 mu m. With the increase of aging heat treatment times from 0 to 4 times, the critical current density increased from 492 A/mm(2) to 2615 A/mm(2) at 5 T&4.2 K. The critical current density of the wire has a weak correlation with the twist pitch of 14.7 mm to 5.3 mm. The hysteresis loss of the wire is 41.6 mJ/cm(3) at +/- 3 T and the D-eff is 2.62 mu m. The RRR(300 K/10K) of the wire is more than 200, which could improve the thermal stability of the magnet and protect the magnet from quench .
10.1109-TASC.2025.3614564	-1		A new type of superconducting wire with high critical current density, fine filament, ultra-low loss experimental NbTi/Cu5Ni/Cu has been developed in this paper for the miniaturized heavy ion therapy device of China. The wire uses Cu-5%Ni alloy instead of conventional high-purity OFC as the matrix, which could prevent the coupling between filaments at low temperature and reduce the eddy current loss effectively. Meanwhile, the Cu5Ni matrix and NbTi filament are separated by high-purity Nb. Nb, as a barrier layer, could isolate the diffusion reaction between Cu and Ti in the process of high-temperature and long-time aging heat treatment. In order to reduce the hysteresis loss of the wire, the filament inside the wire is increased to 75276. The filament diameter is reduced to 1.9 mu m under wire diameter of Phi 0.8 mm. Due to large number of filaments of the wire, filament breakage and wire breakage phenomena occur during processing of the wire. The J(c) (4.2 K, 5 T) of the wire is only 2410 A/mm(2), and the n value is only 17.9. The hysteresis loss (4.2 K, +/- 3 T) of the wire is 19.9 mJ/cm(3), which reached a new higher level in history.
10.1109-TCPMT.2021.3121079	-1		In this study, a thick film copper-nickel alloy (Cu-Ni alloy) was fabricated by using a novel technique which combines thick film process and galvanic chemical replacement. First, a thick film Al electrode was screen printed and sintered at 600 degrees C on the aluminum oxide (Al2O3) substrate which served as a reactant. Sequentially, the Al electrode on Al2O3 substrate was immersed into a copper sulfate (CuSO4) solution at 40 degrees C for 15-30 min to carry out the first galvanic replacement reactions of the partial Al electrode into Cu. After which it was immersed into an NiSO4 solution 80 degrees C for 15 min to carry out the second galvanic replacement reactions of the remaining Al electrode into Ni to form Cu-Ni layers on the Al2O3 substrate. To make a thick film Cu-Ni alloy, the Cu-Ni layers on Al2O3 substrate were annealed at high temperatures for interdiffusion of Cu and Ni. A thick film Al electrode on an Al2O3 substrate is immersed into a CuSO4(aq) solution at 40 degrees C for 15 min and sequentially immersed in an NiSO4(aq) solution at 80 degrees C for 15 min. Then, after further annealing at 800 degrees C for 30 min in a reducing atmosphere, the Cu and Ni composition ratio in the thick film Cu-Ni alloy is approximately 1:1, reflecting Cu-Ni alloy resistor with a very promising temperature coefficient of resistance (TCR) performance (115 ppm/degrees C).
10.1109-TDEI.2017.006266	-1		Experiments concerning the self-breakdown voltage characteristics have been done and a simplified model has been proposed to describe the phenomena in this study. A test platform has been established to investigate the Cu-W (90 wt%) two-electrode switch working in a small airtight cavity (1.2 L). The switch was tested under the conditions of frequency of similar to 0.1 Hz, self-breakdown voltage of similar to 30 kV, and peak current of similar to 60 kA for more than 20000 shots. Inevitably, the process is accompanied with the insulation and electrode's aging in the switch, including the variation of gas components and electrode surface states, which eventually alters the self-breakdown voltage. The results of the experiment demonstrated that the lifetime of the switch could be divided into three stages. In the third stage, this switch showed a satisfactory reliability and stability of the self-breakdown voltage: mean of 32.4 kV and standard deviation of 2.0 %. Besides, from the view of statistics, calculation results proved that the 20000 shots' self-breakdown voltage obeyed mixed Normal distribution, whereas a continuous small sample of that simply followed Normal distribution or Weibull distribution. Moreover, it could be anticipated from the results that the Cu-W spark gap switch could have a lifetime more than 20000 shots (total charge transferred was 13259 C). However, in fact, the lifetime was terminated in advance by insulation degradation in the switch .
10.1109-TMAG.2014.2327153	2	corrosion; surface; film; electrochemical; films; spectroscopy; layer; current; solution; potential; resistance; composition; x-ray; ions; showed	Cu-Co-Ni alloys were electrodeposited in the mediums that have different pH levels to investigate the microstructure-magnetic relationship. The electrolyte pH was considered as high (4.2) and low (2.5) levels. For both levels, the anomalous codeposition occurred in the deposition of the alloys. The face centered cubic crystalline structure was observed in the ternary alloys grown at high and low electrolyte pH levels. In addition, a significant decrease in average grain size of the crystallites, from 60 to 21 nm, occurred when the pH was reduced from 4.2 to 2.5. A dendritic structure was detected in the surface of the alloy deposited from electrolyte with the high pH level, whereas the alloy grown at the low pH has a surface without dendritic clumps. According to magnetic analysis, an increase in the saturation magnetization, caused by the increase of Co content, was detected when the pH was reduced. The coercivity H-c levels were 89 and 80 Oe for the alloys grown at high and low pH, respectively. The change of H-c was attributed to the changes in microstructural properties, i.e., different average grain sizes of the crystallites and surface morphologies, occurred when the electrolyte pH changed. The anisotropic magnetoresistance (AMR) was exhibited by the alloys and the AMR ratio was enhanced from similar to 3% to similar to 3.5%-4% when the pH decreased.
10.1111-arcm.12579	2	corrosion; surface; film; electrochemical; films; spectroscopy; layer; current; solution; potential; resistance; composition; x-ray; ions; showed	A representative group of seal dies made of copper alloys from the collection of the National Museum of Slovenia was investigated by energy-dispersive X-ray fluorescence spectrometry (EDXRF). Chronologically, the artefacts date from the early 13th century to the present. Non-destructive EDXRF screening of elemental fingerprints of Cu, Zn, Pb, Ag, Sn and Sb was performed on 95 seal dies, and the obtained elemental data set was further processed by chemometric tools such as principal component analysis (PCA). The relationships between the elemental composition of analysed seal dies, type of alloy applied and their historical context-date, location of manufacture and, possibly, social rank of the owner-were examined in detail.
10.1111-arcm.12668	2	corrosion; surface; film; electrochemical; films; spectroscopy; layer; current; solution; potential; resistance; composition; x-ray; ions; showed	Recent research has brought the prolific bronze industry of Bronze Age Colchis (modern western Georgia) into focus, but many aspects are still poorly understood. This study synthesizes and reinterprets legacy Cu alloy compositional data to investigate technological choices and spatial patterning. It reveals a massive injection of fresh copper into the system during the Late Bronze-Early Iron Age, and a high degree of selectivity in the alloys used for different objects, with colour being as important as hardness in determining these choices. Spatial analyses show significant geographical variability in alloying practices, which map onto topographical zones in unexpected ways. We also explore recycling practices and argue that the term encompasses a range of different reuse activities, which may be employed under differing economic conditions. Finally, the data suggest relatively extensive primary alloying of tin and copper in the Late Bronze and Early Iron Ages, which further substantiates the speculation that some local tin sources were exploited.
10.1111-arcm.12729	-1		Excimer nano-second laser ablation inductively coupled plasma mass spectrometry (ns-LA-ICP-MS) is an important tool in chemical characterization of Cu alloys. However, variable matrix-induced elemental fractionation in Cu alloys poses a significant challenge. We systematically investigate this issue by analysing the Cultural Heritage Alloy Reference Material Set (CHARM) of Cu alloy targets. The extent to which silicate glass reference materials can be used when analysing Cu alloy targets is determined, as is the optimal internal standard, for a wide range of Cu alloy compositions. Analyses were further optimized by quantitative assessments of the use of CHARM end-member materials as external standards for other CHARM Cu alloy targets. The variable magnitude of the observed matrix effects is most readily explained by variations in Cu/Zn ratios and resulting differences in melting and boiling points, compared with external reference materials, making the Zn-rich Cu alloy targets most prone to matrix effects. With the correct choice of an external matrix-matched standard (Pb-rich CHARM reference material 32X LB14F) and internal element standardization, an accuracy of < 20% can be achieved for virtually all elements of interest in brass and bronze artefacts, which is a significant improvement compared with the use of glass external reference materials.
10.1111-ffe.13842	-1		The present study addressed the cyclic deformation behavior and fatigue properties of Cu-0.69Cr-0.07Zr alloy with different cold deformation (epsilon = 64%, 75%, and 84%) using low cycle fatigue test. Low cycle fatigue tests were conducted under fully-reversed conditions at different total strain amplitudes. The microstructure changes and fatigue fracture characteristics were analyzed by scanning electron microscope (SEM) and transmission electron microscope (TEM). The main findings suggest that the Bauschinger effect was significantly stronger with larger deformation at low total strain amplitude. And it was proved that the relationship between the total strain amplitude and the low cycle fatigue life of Cu-Cr-Zr alloy with different deformation can be expressed by the Manson-Coffin-Basquin formula. Further, the reason for the fatigue life was shorter and the cyclic softening rate decreased faster at high applied total strain amplitude was that the dislocation density decreased due to the rearrangement of the dislocations.
10.1111-ffe.14544	-1		The enhanced fatigue resistance of superelastic Cu-Al-Mn shape memory wires was investigated via a bamboo-like grain structure obtained by cyclic heat treatment (CHT). Our findings reveal that increasing the number of CHT cycles facilitates grain growth, and the grain boundary will change from a brittle triple junction to a stronger straight grain boundary. This structural feature of grain boundaries alleviates stress concentration effects on dislocation motion. In particular, the 5CHT and 7CHT samples displayed negligible residual strain after unloading, following exposure to cumulative strains ranging from 2% to 10%, thereby showcasing superior superelasticity. From the functional fatigue test, the fatigue life of the shape memory wire subjected to 5CHT cycles exceeds 4650 cycles at 5% strain, which is more than five times that of the traditional polycrystalline quenched sample.
10.1111-ijac.13703	17	wear; composites; coating; friction; composite; coatings; surface; tribological; properties; wear resistance; resistance; powder; sliding; matrix; wear rate	Ternary Cu-Fe-Si alloy were applied to modify tribological behavior of carbon fiber/carbon-silicon carbide (C-f/C-SiC) composites by reactive melt infiltration. Microstructures, physical properties and tribological properties on a full-scale train brake test rig of the modified composites were studied. Results indicate that both Cu and Fe-Si alloy as matrices lead to significantly enhanced thermal conductivity and compressive strength for C-f/C-SiC composites. Moreover, the average friction coefficient of the modified composites is between 0.25 and 0.55, which is higher than that of copper metal matrix composites. In addition, the average volume wear rate of the modified composites is only 0.168 cm(3)/MJ. The C-f/C-SiC composites modified by Cu and Fe-Si alloy with improved physical properties and tribological properties meet the technical requirement and show high application potential in express train brake systems.
10.1111-j.1365-2818.2009.03250.x	6	grain; deformation; strain; strength; dislocation; cu-; tensile; size; ecap; grain size; sfe; ductility; hardening; high; stress	The microstructure and texture of Cu-8 at% Al alloy single crystal with (112)[11 (1) over bar] orientation plane strain compressed at 77 K were characterized by scanning electron microscope and transmission electron microscope orientation mappings in order to investigate the influence of twins and shear bands on slip propagation across a structure of twin-matrix layers and the resulting texture evolution. It was shown that the strong, initial texture changes are due to deformation twinning at low deformations. At larger deformations, twin-matrix bending within some narrow areas led to the formation of kink-type bands, which became the precursors of shear bands. It is shown with scanning electron microscope and transmission electron microscope orientation mappings how the structure of twins and matrix was incorporated into the shear band, and what kind of the dislocation mechanism was responsible for strain accommodation at the macroscale. It was found that the reorientation of the main (111) twinning planes towards the shear band plane facilitates further dislocation slip in the shear direction.
10.1111-j.1475-1305.2008.00552.x	16	wear; composite; composites; powders; milling; particles; powder; wt; sliding; friction; hardness; matrix; mechanical; surface; properties	Bonding between dissimilar metallic (copper) and non-metallic particles (Al2O3) was successfully achieved. The mechanical properties of the copper composite nano-structure with different Al2O3 particle sizes ranging from 100 nm to 20 mu m were investigated. The alloys were prepared by using electro-less precipitation and particle metallurgy technique at three different sintered temperatures, 900, 950 and 1000 degrees C. The chemical composition of composites were 85 atomic % Cu and 15 atomic % Al2O3, of which commercially available Al2O3 particles with a purity of 99.5% were used. The microstructure, hardness and compressive stress-strain behaviours were determined. A pin-on-disc system was used to study wear. Electrical resistivity was also measured.
10.1111-jace.13240	2	corrosion; surface; film; electrochemical; films; spectroscopy; layer; current; solution; potential; resistance; composition; x-ray; ions; showed	This article reports the characterization of thin films sputtered from CuAl1-xCaxO targets (x=0, 0.05, 0.1, 0.15, and 0.2) at room temperature. All films exhibit amorphous/nanocrystalline structures. Their transparency increases slightly with the addition of Ca. Furthermore, the resistivity decreases as the Ca/Al atomic ratio increases. Transmission electron microscopy with energy dispersive spectroscopy mapping indicates that the composition is uniform throughout the films deposited from the highest Ca doping concentration target. Some nanocrystals are present at the top surface of the CuAl0.8Ca0.2O thin film as well as the interface region between the CuAl0.8Ca0.2O thin film and the glass substrate, whereas the interior of the film is pretty amorphous with some embedded nanocrystals. X-ray photoelectron spectroscopy shows that the Cu2+/Cu+ atomic ratio increases with the Ca/Al atomic ratio, indicating the enhancement of p-type conductivity from the nonisovalent Cu-O alloying.
10.1111-jmi.13136	-1		Severe plastic deformation (SPD) is a widely used technique to obtain superior material properties specially mechanical properties. Constrained groove pressing (COP) is found to be the most attractive SPD technique for the deformation of sheets and plates. However, this technique results in microstructural inhomogeneity during processing. The microstructural inhomogeneity can be alleviated by employing a thermal cycle, which assists in controlled recovery and recrystallisation. The current work focuses on, the microstructure evolution of one pass as-deform CGP sample followed by a short heat-treated (SHT). A correlative imaging technique of transmission Kikuchi diffraction (TKD) and transmission electron microscopy (TEM) showed the presence of dislocation cell structure in an as-deformed condition. The short heat treatment resulted in the transformation of the dislocation cell wall to high-angle boundaries, with a further increase in heat-treatment time resulting in grain growth .
10.1115-1.1448324	4	transformation; martensite; martensitic; phase; shape; beta; memory; shape memory; temperature; temperatures; martensitic transformation; gamma; transformation temperatures; effect; thermal	This paper is concerned with the mechanical behavior of a Cu-Al-Be Shape Memory Alloy (SMA). A large experimental database, made of tension-internal pressure tests and biaxial compressive tests, is reported. Particular attention is paid to the behavior of the material under multiaxial proportional and nonproportional loadings. Moreover these two types of complementary tests allow for the determination, on the one hand, of the shape of the initial surface of transformation onset and, on the other hand, of the initial direction of the transformation strain rate. A generalized macroscopic J(2)-J(3) criterion to describe the transformation onset is proposed and identified.
10.1115-1.4036185	16	wear; composite; composites; powders; milling; particles; powder; wt; sliding; friction; hardness; matrix; mechanical; surface; properties	The modern technology developments have seeded for the necessity of composite materials that are incorporated with high hardness, high tensile strength, and better wear properties. Cu-Sn-Ni alloy as well as the composites of varying weight percentage of Si3N4 (5, 10, and 15) are fabricated by liquid metallurgy technique. The alloy and composites are tested for their tensile strength and hardness on Universal Testing Machine and Vickers microhardness tester, respectively. Based on the tests, Cu-Sn-Ni/10 wt% of Si3N4 is found to have optimum mechanical properties. The scuff type adhesive wear behavior is studied through pin-on-disk tribometer under dry sliding conditions for Cu-Sn-Ni/10 wt% of Si3N4 composite. Taguchi's design of experiments technique based on L-27 orthogonal array model is used for analyses of process parameters in three levels such as applied load (10, 20, and 30 N), sliding distance (500, 1000, and 1500 m), and sliding velocity (1, 2, and 3 m/s). The parameters are ranked based on the signal-to-noise ratio and the analysis of variance approach . Based on wear results, applied load is found to have highest stature on influencing wear rate followed by sliding distance and sliding velocity. A generalized wear rate equation is obtained based on the linear regression model and its feasibility is checked. Scanning electron microscope (SEM) analyses revealed severe delamination occurred on maximum load condition. The development of this copper composite can have the possibility of replacing aluminum bearings.
10.1115-1.4037767	16	wear; composite; composites; powders; milling; particles; powder; wt; sliding; friction; hardness; matrix; mechanical; surface; properties	A functionally graded Cu-10Sn-5Ni metal matrix composite (MMC) reinforced with 10 wt% of Al2O3 particles was fabricated using the centrifugal casting process with dimension Phi(out)100 x Phi(in)85 x 100 mm. The mechanical and wear resistance of the composite has been enhanced through heat treatment. Samples from of the inner zone (9-15 mm) were considered for heat treatment, as this zone has higher concentration of less dense hard reinforcement particles. The samples were solutionized (620 degrees C/60 min) and water quenched followed by aging at different temperatures (400, 450, and 550 degrees C) and time (1-3 h). Optimum parametric combination (450 degrees C, 3 h) with maximum hardness (269 HV) was considered for further analysis. Dry sliding wear experiments were conducted based on Taguchi's L27 array using parameters such as applied loads (10, 20, and 30 N), sliding distances (500, 1000, and 1500 m), and sliding velocities (1, 2, and 3 m/s). Results revealed that the wear rate increased with load and distance whereas it decreased initially and then increased with velocity. Optimum condition for maximum wear resistance was determined using signal-to-noise (S/N) ratio. Analysis of variance (ANOVA) predicted the major influential parameter as load, followed by velocity and distance. Scanning electron microscope (SEM) analysis of worn surfaces predicted the wear mechanism, observing more delamination due to increase in contact patch when applied load increased. Results infer 8% increase in hardness after heat treatment, making it suitable for load bearing applications.
10.1115-1.4045721	16	wear; composite; composites; powders; milling; particles; powder; wt; sliding; friction; hardness; matrix; mechanical; surface; properties	Among all the materials, diamond turning of heterogeneous materials like copper beryllium (CuBe) poses serious machining challenges as the heterogeneity in the workpiece affects the quality of generated surface. Therefore, the present study is aimed to understand the effect of tool-workpiece interactions on the surface characteristics of heterogeneous CuBe workpiece material. Experiments and molecular dynamics simulation (MDS) were carried out to analyze the various surface and subsurface interactions during cutting. Results from the experiments on both the materials for whole cutting length show that the average roughness values on CuBe-machined surface are found to be similar to 48% higher than those of copper (Cu). Scanning electron microscopy (SEM) results show that while deterministic lay pattern is obtained in the case of Cu, the CuBe-machined surface possesses near-random lay pattern, which is also reflected by the fast Fourier transform (FFT) spectrum of surface roughness profiles. Experimental and MDS results reveal that the hard precipitate suffers cracks which propagate vertically as well as radially and as the tool travels from Curich phase to Be-rich phase, ductile to brittle transition in cutting mechanism is observed. Furthermore, it is observed that diamond-turned Cu and CuBe surfaces are contaminated by the oxides of C and Cu. MDS results verify the mechanisms involved in the surface and subsurface interactions during diamond turning.
10.1115-1.4046624	17	wear; composites; coating; friction; composite; coatings; surface; tribological; properties; wear resistance; resistance; powder; sliding; matrix; wear rate	The continuous emergency braking performance of copper-based brake pads alloyed with different Ni contents were tested. The results showed that the copper-based brake pad with high Ni content exhibits improved stability of friction coefficient during the whole emergency braking process, which indicates that Ni helps to reduce the sensitivity of the brake pad to the change of braking conditions. Moreover, the fade phenomenon of friction coefficient is obviously alleviated as the increase in Ni content under high-pressure and high-speed braking conditions. The introduction of Ni enhances the plastic deformation resistance of friction surface and promotes the formation of high-strength mechanical mixed layer and thick tribo-oxide film. This stable tribo-film remained on the contact interface is responsible for the steady mean friction coefficient under different braking conditions. Excessive addition of Ni reduces the plasticity of the friction surface, leading to the change of the main wear mechanism from adhesive wear to delamination
10.1115-1.4056282	17	wear; composites; coating; friction; composite; coatings; surface; tribological; properties; wear resistance; resistance; powder; sliding; matrix; wear rate	The tribological behaviors of Cu-based bulk metallic glass (BMG) Cu50.2Zr40.8Ti8.5Nb0.5 and conventional nickel-aluminum bronze (NAB) reference material were investigated in air and in 3.5% NaCl solution, respectively. The tribology tests were performed at room temperature using a reciprocating tribometer at a sliding speed of 1 m min(-1) against a 6-mm diameter ZrO2 ball. When sliding in air, the friction coefficient of Cu-based BMG decreases with the applied loads (5 N, 10N, and 20 N), and the wear behavior is mainly affected by abrasion, delamination, and oxidation. In particular, the wear-rate of Cu-based BMG is about 22 times lower than that of conventional NAB when sliding in the air under a load of 5 N. When sliding in 3.5 wt% NaCl solution, Cu-based BMG demonstrates better static-corrosion resistance but worse tribocorrosion resistance compared with conventional NAB. Due to the combined effects of corrosion and lubrication caused by the solution, the wear-rate of the BMG in NaCl solution increases at 5 N, but decreases at 20 N when compared with the corresponding wear in air. The tribocorrosion of Cu-based BMG is mainly controlled by abrasive wear and the synergistic effects of abrasion and corrosion. By applying -1.3 V cathodic potential, the corrosive wear-rate of Cu-based BMG at 5 N was reduced by nearly 50%. This work provides an experimental reference for the tribological evaluation of Cu-based BMG in different environments.
10.1116-1.3273533	-1		The position of segregated Al atoms in the ordered (root 3x root 3)R30 degrees superlattice phase on the (111) surface of a Cu-9 at. % Al alloy was precisely determined by tensor low energy electron diffraction (LEED) analysis. Work function values of the superlattice phase, the alloy without Al segregation, and Cu (111) were measured and compared. Both the position of segregated Al atoms and the work function values were computed using first-principles calculations. The conclusion from the tensor LEED analysis that the segregated Al atoms, occupying substitutional positions in bulklike lattice sites within the top layer, were located outward by 6% with respect to the plane of the top layer Cu agreed well with the calculations. The results that the work function of the alloy surface with substitutional Al segregation was very close to that without Al segregation were obtained from both the experiments and the calculations. The effect of segregation of atoms and the position of segregants on the work function value was also discussed. (C) 2010 American Vacuum Society. [DOI: 10.1116/1.3273533]
10.1116-1.5088936	2	corrosion; surface; film; electrochemical; films; spectroscopy; layer; current; solution; potential; resistance; composition; x-ray; ions; showed	Antimicrobial surfaces such as copper alloys can reduce the spread of pathogenic microorganisms, e.g., in healthcare settings; however, the surface chemistry and thus the antibacterial activity are influenced by environmental parameters such as cleaning and disinfection procedures. Therefore, the purpose of the present study was to assess how copper-complexing compounds (chlorides and phosphates), common to the clinical environment, can affect the surface chemistry and the antiadhesive and antibacterial properties of a newly developed antibacterial copper-silver alloy and the single alloying metals. The authors demonstrated that the antiadhesion efficacy against S. aureus 8325 was the highest when the copper-silver alloy and copper surfaces (four-and two-log bacterial reduction compared to stainless steel controls, respectively) were exposed to chloride-containing suspensions. This was explained by the electrochemical activity of copper that dissolved as Cu+, highly toxic to the bacterial cells, in the presence of Cl-and eventually formed a chlorine-and oxygen-rich layer with the incorporation of phosphorus, if also phosphates were present. If chlorides were omitted from the wet environment, there was no difference (P > 0.05) in bacterial counts on copper-silver alloy, copper, silver, and AISI 316 stainless steel control surfaces, due to the fact that no oxidizing conditions were established and therefore there was no dissolution of copper ions from copper-silver alloy and copper surfaces. However, under dry conditions, copper-silver alloy and pure copper surfaces were antibacterial also in the absence of chlorides, suggesting a marked difference between dry and wet conditions in terms of the interactions between surfaces and bacteria. The authors conclude that an attentive design of control policies integrating disinfection interventions and antimicrobial surfaces, such as the copper-silver alloy coating, can be a beneficial solution in fighting the spread of antibiotic resistant bacterial strains and potentially reducing the number of disease outbreaks. Published by the AVS.
10.1116-1.5134676	2	corrosion; surface; film; electrochemical; films; spectroscopy; layer; current; solution; potential; resistance; composition; x-ray; ions; showed	Antimicrobial properties of solid copper (Cu) surfaces against various microorganisms have been demonstrated, but little is known about the durability and relative antimicrobial efficacy of different Cu formulations currently used in healthcare. The aim of this study was to assess whether three different formulations of copper-bearing alloys (integral, spray-on and Cu-impregnated surfaces) and a stainless steel control differed in their antimicrobial efficacy, durability, and compatibility with hospital-grade cleaner/disinfectants. The U.S. Environmental Protection Agency draft protocol for the evaluation of bactericidal activity of Cu containing alloys was modified to more accurately reflect cleaning methods in healthcare. The three different Cu alloys were evaluated using 25 x 25 x 3 mm disks subjected to one year of simulated cleaning and disinfection using the Wiperator (TM) with microfiber cloths presoaked in three common hospital disinfectants: accelerated hydrogen peroxide, quaternary ammonium, or sodium hypochlorite solutions. Bactericidal activity was evaluated using Staphylococcus aureus and Pseudomonas aeruginosa. While all Cu formulations exhibited some antimicrobial activity, integral and spray-on Cu alloys showed the greatest efficacy. Assessments of durability included documentation of changes in mass, morphological changes by scanning electron microscopy, chemical composition alteration by energy-dispersive x-ray spectroscopy, and surface roughness alteration using profilometry over one year of simulated use. The integral Cu alloy had the least mass loss (0.20% and 0.19%) and abrasion-corrosion rate (6.28 and 6.09 mu m/yr) compared to stainless steel. The integral product also showed the highest durability. Exposure to disinfectants affected both the antimicrobial efficacy and durability of the various copper products.
10.1116-6.0002480	2	corrosion; surface; film; electrochemical; films; spectroscopy; layer; current; solution; potential; resistance; composition; x-ray; ions; showed	In situ elemental analysis of films comprising multielements deposited by sputtering is necessary to improve the reliability of the films because small changes in the film composition affect the properties of the films. Recently, we developed a method to determine the composition of Cu-Zn films by measuring the intensities of emission lines of Cu and Zn during sputter deposition. However, this method was only applicable to a constant chamber pressure, and only a narrow composition range (65.9-80.6 at. % of Cu in the target) was investigated. In this study, the applicability of this method was investigated for a wide range of film compositions, and the combination of emission lines that can be used to determine the film composition regardless of the chamber pressure was determined. This was achieved using Ni-Cu alloy targets, whose Cu composition ranged from 29.4 to 85.3 at. %, by evaluating the linearity (R-2 value) between the emission intensity ratio of Ni/Cu lines and the atomic ratio of Ni/Cu in the films. An R-2 value of 0.9870 was obtained for the combination of Ni 338.1 nm and Cu I 296.1 nm lines at chamber pressures from 1 to 5 Pa. This result indicates that the composition of Ni-Cu films can be determined from the intensities of the emission lines of Ni and Cu during sputter deposition regardless of the chamber pressure.
10.1116-6.0003374	-1		In this paper, a Cu-Mo alloying layer with improved properties was fabricated by high current pulsed electron beam (HCPEB) irradiation. The microstructure of the modified layer was investigated by x-ray diffraction, scanning electron microscopy, and transmission electron microscopy. The microhardness and friction properties were also measured. After HCPEB irradiation, nano Mo particles, solid solution, and long-period superlattice structures were generated on the surface of Cu-Mo alloys, together with the formation of defect structures. These microstructures led to a significant increase in the surface hardness. The results of sliding wear tests indicated that the HCPEB-irradiated samples exhibited better properties compared with the initial one, which was attributed to the ultrafine Mo particles and the hardened surface.
10.1126-sciadv.1601942	-1		The coefficient of friction (COF) of metals is usually high, primarily because frictional contacts induce plastic deformation underneath the wear surface, resulting in surface roughening and formation of delaminating tribolayers. Lowering the COF of metals is crucial for improving the reliability and efficiency of metal contacts in engineering applications but is technically challenging. Refining the metals' grains to nanoscale cannot reduce dry-sliding COFs, although their hardness may be elevated many times. We report that a submillimeter-thick stable gradient nanograined surface layer enables a significant reduction in the COF of a Cu alloy under high-load dry sliding, from 0.64 (coarse-grained samples) to 0.29, which is smaller than the COFs of many ceramics. The unprecedented stable low COF stems from effective suppression of sliding-induced surface roughening and formation of delaminating tribolayer, owing to the stable gradient nanostructures that can accommodate large plastic strains under repeated sliding for more than 30,000 cycles.
10.1126-sciadv.aaz8003	-1		Inherent thermal and mechanical instability of nanograined materials bottlenecks their processing and technological applications. In addition to the traditional stabilization strategy, which is based on alloying, grain boundary relaxation was recently found to be effective in stabilizing nanograined pure metals. Grain boundary relaxation can be induced by deforming very fine nanograins below a critical size, typically several tens of nanometers. Here, we found that rapid heating may trigger intensive boundary relaxation of pure Cu nanograins with sizes up to submicrometers, a length scale with notable instability in metals. The rapidly heated Cu nanograins remain stable at temperatures as high as 0.6 T-m (melting point), even higher than the recrystallization temperature of deformed coarse-grained Cu. The thermally induced grain boundary relaxation originating from the generation of high-density nanotwins offers a alternative approach to stabilizing nanostructured materials.
10.1126-science.adr0299	-1		We present a bulk nanocrystalline copper alloy that can operate at near-melting temperatures with minimal coarsening and creep deformation. The thermal stability of the Cu-3Ta-0.5Li atomic % (at%) alloy is attributed to coherent, ordered γ′ Cu3Li precipitates surrounded by a tantalum-rich atomic bilayer phase boundary complexion. Adding 0.5 at% lithium to the immiscible Cu-Ta system changes the morphology of the nanoscale precipitates from spherical to cuboidal while simultaneously tailoring the phase boundary. The resultant complexion-stabilized nanoscale precipitates provide excellent thermal stability, strength, and creep resistance. The underlying alloy design principles may guide the development of next-generation copper alloys for high-temperature applications such as heat exchangers.
10.1127-ejm-2017-0029-2651	-1		The condensed-phase system Cu-Pd-Se was investigated by means of dry syntheses from elements in evacuated silica glass tubes at 650 degrees C, 550 degrees C, 400 degrees C, and 300 degrees C. Synthetized phases were analysed by electron microprobe and textural studies in polished sections. At 650 degrees C an extensive selenide liquid field covers central portions of the system, coexisting with a limited choice of Pd selenides, Cu2-xSe, alloys, and a (Cu, Pd) Se-2 solid solution. The selenide melt recedes to the Pd side of the system at 550 degrees C and its remnants persist at 400 degrees C. At the lower temperature, the gamut of Pd selenides becomes richer, and especially Pd4Se and Pd17Se15 display significant solubility of Cu. The composition range of (Cu, Pd) Se-2 broadens and moves towards Cu-richer compositions as temperature decreases; CuSe and CuSe2 appear at 300 degrees C. The synthetic analogue of jagueite, Cu2Pd3Se4, is present at 400 degrees C and 300 degrees C, at Se concentrations above the Cu2-xSe-Pd17Se15 line. At all examined temperatures, the individualized CuPd alloy dissolves Se, up to similar to 5 at% at low temperatures.
10.1134-1.1434487	4	transformation; martensite; martensitic; phase; shape; beta; memory; shape memory; temperature; temperatures; martensitic transformation; gamma; transformation temperatures; effect; thermal	The internal friction and velocity of ultrasonic waves in the beta phase of Cu-Al-Ni single crystals are measured at a frequency of 5 MHz in the temperature range 190-300 K, including the range of thermoelastic martensite transformation. The effect of impact loading (5 GPa) on the elastic and dissipative characteristics of the samples is investigated. The results obtained are discussed within the framework of existing theoretical concepts on the martensite transformation mechanisms responsible for the acoustic characteristics of a material. (C) 2002 MAIK Nauka/ Interperiodica.
10.1134-1.1553541	4	transformation; martensite; martensitic; phase; shape; beta; memory; shape memory; temperature; temperatures; martensitic transformation; gamma; transformation temperatures; effect; thermal	The influence of neutron irradiation on the temperature kinetics of thermoelastic martensitic transformation in a Cu-Al(13.4%)-Ni(5%) alloy single crystal is investigated by measuring the electrical resistivity directly under irradiation of the sample in a nuclear reactor channel. It is revealed that, after irradiation of the crystal in a martensitic or two-phase state, the temperature of the phase transition upon heating becomes 25-30 K higher than that prior to irradiation. This shift in the transition temperature is observed only upon the first heating, and the kinetics of martensitic transformation is restored in subsequent thermocycles. The shift in the transformation temperatures after irradiation increases with an increase in the fluence. The experimental results are explained by a disturbance of coherence at the interfaces in the irradiated crystals. (C) 2003 MAIK Nauka / Interperiodica.
10.1134-S0020168511120016	12	thermodynamic; ternary; phase; data; experimental; equilibria; phase equilibria; liquid; binary; experimental data; calculated; phases; literature; model; calphad	The Cu-Tl-Se system has been studied at temperatures from 300 to 420 K using emf measurements with Cu4RbCl3I2 as a Cu+ ion conducting solid electrolyte. The emf data have been used to map out the subsolidus phase diagram of the Cu-Tl-Se system in the composition region Tl2Se-CuTlSe-CuSe-Se. We have calculated the partial molar thermodynamic functions of the copper in the alloys and the standard thermodynamic functions of formation and standard entropies of the ternary compounds CuTlSe2, CuTlSe, and Cu2TlSe2. The results confirm that the thermodynamic properties of copper-containing ternary systems can be studied using the approach in question even when they contain an element (thallium in this study) located to the left of copper in the electrochemical series.
10.1134-S0020168512020021	12	thermodynamic; ternary; phase; data; experimental; equilibria; phase equilibria; liquid; binary; experimental data; calculated; phases; literature; model; calphad	The Cu-As-S system has been studied at temperatures from 300 to 370 K using emf measurements with Cu4RbCl3I2 as a Cu+ ion conducting solid electrolyte, and its subsolidus phase diagram has been mapped out, including the ternary compounds Cu3AsS4, Cu6As4S9, Cu4As2S5, Cu3AsS3, and CuAsS. From the emf data, we have calculated the partial molar thermodynamic functions and of the copper in the alloys and the standard thermodynamic functions of formation and standard entropies of the ternary compounds.
10.1134-S0020168521110054	-1		The phase composition, texture, and substructure of foil of a Cu-36.4 at% Pd solid solution have been studied by X-ray diffractometry and electron diffraction after rolling to a thickness of 320, 220, 180, 100, and 30 mu m and subsequent heat treatment in vacuum to a temperature exceeding the upper temperature stability limit of an ordered structure. The results demonstrate that the general trends of changes in texture observed at all foil thicknesses during both deformation and subsequent heat treatment are controlled by ordering processes according to the Bain model and disordering processes, with allowance for the role of rolling deformation and recrystallization during subsequent heat treatment. At all foil thicknesses, heat treatment of the deformed samples leads to a decrease in the lattice parameter of the alpha-phase and an increase in that of the beta-phase, suggesting an increase in the percentage of Pd in the beta-phase and a decrease in that in the alpha-phase. The small change in the lattice parameter of the alpha-phase ensures the possibility of a complete alpha -> beta transformation.
10.1134-S0020168523060171	4	transformation; martensite; martensitic; phase; shape; beta; memory; shape memory; temperature; temperatures; martensitic transformation; gamma; transformation temperatures; effect; thermal	We have studied the kinetics of the disorder -> order (A1 -> L1(0)) transformation in Cu-56Au nonstoichiometric alloy at a temperature of 250 degrees C. The disordered initial state of the alloy was produced by either quenching of samples from a high temperature or plastic deformation. The results demonstrate that the rate of atomic ordering in the quenched alloy is extremely low: the transformation needs approximately two months of annealing at a temperature of 250 degrees C to reach completion. The rate of atomic ordering in predeformed samples is even lower. In both an as-quenched and an ordered state, the lattice parameters of the alloy under investigation slightly exceed those of the equiatomic alloy. Independent of the initial state of samples, their microhardness first rises in the course of atomic ordering and then falls off. The resistivity of Cu-56Au alloy in a well-ordered state has been shown for the first time to be rho = 7.04 x 10(-8) omega m, which is far lower than was thought previously. The data we obtained have been used to assess the ratio of the phases present (order/disorder) in different stages of annealing.
10.1134-S0021364014200107	-1		The reversible wetting of grain boundaries by the second solid phase in the copper-indium system has been observed. With an increase in the temperature, the contact angle. between the (Cu)/(Cu) grain boundary in a Cu-based solid solution based and particles of the delta-phase (Cu70In30) decreases gradually. Above T-W = 370 degrees C, the first (Cu)/(Cu) grain boundaries completely wetted by the delta phase appear in Cu-In polycrystals. In other words, the delta phase forms continuous layers along grain boundaries and theta = 0. At 440 degrees C, the fraction of completely wetted grain boundaries reaches a maximum (93%), whereas the average contact angle reaches a minimum (theta = 2 degrees). With a further increase in the temperature, the fraction of completely wetted grain boundaries decreases and vanishes again at T-DW = 520 degrees C. This phenomenon can be explained by an anomalous shape of the solubility limit curve of indium in a solid solution (Cu).
10.1134-S0031918X07120046	-1		Surface tension of pure copper and its alloys with Sn has been measured at 1000 degrees C in a hydrogen atmosphere. Surface tension of a free surface equaled 1.81 N/m for pure copper, and 1.55, 1.38, and 1.28 N/m for the alloys with 0.05, 0.22, and 0.33 at% Sn, respectively; surface tension at grain boundaries equaled 0.5 N/m for pure copper, and 0.36, 0.3, and 0.23 N/m for the alloys, respectively. Based on these data, the concentration dependence of tin absorption at a free surface and grain boundaries has been calculated. Parameters of Sn absorption at grain boundaries and a free surface of copper have been compared with those of Sb and Bi.
10.1134-S0031918X16110077	-1		The structure and the process of texture formation in ribbons made of Cu-Ni-M (M = Fe, Cr, V) ternary alloys have been studied upon cold rolling deformation to a degree of similar to 99% and subsequent recrystallization annealing. The possibility of obtaining a perfect cube texture in a thin ribbon made of copper-nickel-based ternary alloys with additives of iron, chromium, and vanadium has been shown, which opens the prospects of the use of these alloys as substrates in the technology of production of tapes of high-temperature second-generation superconductors. Optimal annealing regimes have been determined, which make it possible to obtain a perfect biaxial texture close to single-crystalline one with the content of cube-oriented grains {001}aOE (c) 100 >+/- 10A degrees more than 99% on the surface of the textured ribbon.
10.1134-S0031918X17020041	6	grain; deformation; strain; strength; dislocation; cu-; tensile; size; ecap; grain size; sfe; ductility; hardening; high; stress	Tri-layered alpha-brass-clad Cu-Cr-alloy composite plates were prepared by hot roll-bonding. Neither intermetallic-compound layers nor interface defects were observed at the interfaces in the as-rolled and heat-treated alpha-brass-clad Cu-Cr composite plates. The hardness of the as-rolled alpha-brass layer was greater than that of the Cu-Cr substrate, since the alpha-brass was strengthened by strain hardening more efficiently upon rolling. The hardness of the alpha-brass decreased appreciably upon annealing because of the recovery processes, whereas that of the Cu-Cr layer slightly increased after heat treatment at 450A degrees C due to the precipitation strengthening. After the post-roll-bonding heat treatment at 450A degrees C, the strength of the alpha-brass-clad Cu-Cr-alloy composite decreased with a significant increase in ductility. The electrical conductivity of the asroll-bonded alpha-brass clad Cu-Cr alloy composite (47-52% IACS) increased significantly (to 72-74% IACS) after the 1-h heat treatment. The strength and conductivity of the clad composite are dependent on the precipitation strengthening of Cu-Cr and recovery softening of alpha-brass in the course of the post-roll-bonding heat treatment.
10.1134-S0031918X17020156	-1		The structure of vacuum condensate foils (separated from substrates) of the binary Cu-Ta system has been investigated both in the initial condensed state and after annealings at temperatures of up to 1000A degrees D. It has been shown that the alloying of a vapor flow of the matrix metal (copper) with tantalum to similar to 0.5 at% makes it possible to reduce the grain size from 3 mu m to 50 nm. Depending on the tantalum concentration, condensates exhibit a broad spectrum of structural states, i.e., single- and two-phase, a supersaturated solution of tantalum in the fcc lattice of copper, etc. The structure of the objects possesses a high thermal stability. The temperature of the start of grain growth in the copper matrix depends on the tantalum content and can reach 900A degrees D. The dispersion of the structure of copper condensates and its thermal stability is due to the formation of segregates of tantalum atoms at the boundaries of grains of the copper matrix both in the process of condensation and upon subsequent annealing.
10.1134-S0031918X18040075	-1		The effect of the preliminary high strain-rate deformation, performed via the method of dynamic channel-angular pressing (DCAP), and subsequent annealings on the tribological properties of a dispersionhardened Cu-0.092 wt% Cr-0.086 wt% Zr alloy has been investigated. It has been shown that the surfacelayer material of the alloy with a submicrocrystalline (SMC) structure obtained by the DCAP method can be strengthened using severe plastic deformation by sliding friction at the expense of creating a nanocrystalline structure with crystallites of 15-60 nm in size. It has been shown that the SMC structure obtained by the high strain-rate DCAP deformation decreases the wear rate of the samples upon sliding friction by a factor of 1.4 compared to the initial coarse-grained state. The maximum values of the microhardness and minimum values of the coefficient of friction and shear strength have been obtained in the samples preliminarily subjected to DCAP and aging at 400 degrees C. The attained level of microhardness is 3350 MPa, which exceeds the microhardness of the alloy in the initial coarse-grained state by five times.
10.1134-S0031918X18060030	4	transformation; martensite; martensitic; phase; shape; beta; memory; shape memory; temperature; temperatures; martensitic transformation; gamma; transformation temperatures; effect; thermal	Polycrystalline Cu-Al-Ni-Fe-based shape memory alloys with different chemical composition were produced in an arc-melting furnace under an argon atmosphere. Homogenized and aged specimens were prepared for multiple analyses. The temperatures of reversible martensitic transformations, namely A (s), A (f), M (s), M (f), A (max) and Delta H enthalpy values were determined by a DSC device. The phase transition analysis from the room temperature to 850A degrees C was undertaken by DTA. To characterize the lattice structure, an XRD analysis was conducted, the results of which were confirmed by microstructure images obtained from optical microscope observations.
10.1134-S0031918X1811008X	-1		Transmission electron microscopy was used to perform a structural analysis of a number of binary copper alloys with 3d transition elements after short-term annealing in an oxidative atmosphere (5 and 30min) at a temperature of 700 degrees C. It has been established that the textured tapes of Cu-Cr and Cu-Fe alloys sustain not only surface oxidation in the process of additional annealing, but also internal oxidation. Electron diffraction analysis has shown that a layer of complex spinel-type CuM2O4 oxide (M = Cr, Fe) forms on alloying element particles under annealing, while the precipitation of dispersed copper oxides, predominantly, Cu2O with a small admixture of CuO occurs in the copper matrix. Microhardness analysis has demonstrated that internal oxidation in the tapes of the studied binary alloys does not have an adverse effect on their mechanical properties.
10.1134-S0031918X22010082	-1		Electric properties and microhardness of the Cu-5.9 at% Pd alloy are studied. These characteristics are compared with those of pure copper and Cu-8 at% Pd alloy. The results obtained are discussed using literature data on the properties of compositions close to the stoichiometric Cu3Pd alloy. Dependences of the electrical resistivity of low-alloyed Cu-Pd alloys on the true strain and quenching temperature are plotted. An anomalous decrease in the electrical resistivity of the studied alloys was found to result from both plastic deformation and increase in the quenching temperature. Annealing in a temperature range of 200-300 degrees C was found to lead to an anomalous increase in the microhardness and electrical resistivity. The anomalies found are explained from the viewpoint of the formation of short-range atomic order upon quenching of the low-alloyed Cu-Pd alloys.
10.1134-S0036023610080218	-1		Interactions in the copper-gallium-tin ternary system are studied. New phase formation involves the step of dissolution of solid copper alloys in a liquid phase. The induction period of tin segregation in an autonomous phase depends on tin concentration in the feed. The formation of solid solution of gallium in tin is suggested.
10.1134-S0036024417060231	12	thermodynamic; ternary; phase; data; experimental; equilibria; phase equilibria; liquid; binary; experimental data; calculated; phases; literature; model; calphad	Mixing enthalpies of alloys in the Cu-La system are measured using isoperibolic calorimetry method over the ranges 0 < x (La) < 0.185 at 1400-1430 K and 0.659 < x (La) < 1 at 1370 K. They have moderate exothermic values over the whole concentration range and agree with literature data. Activities of the components, enthalpies and entropies of formation of intermetallics in this system, and its phase diagram are optimized using an ideal associated solution (IAS) model, and agree with most literature data. The updated thermodynamic properties can be used in further investigation of multicomponent systems based on the binary Cu-La.
10.1134-S1023193510030146	12	thermodynamic; ternary; phase; data; experimental; equilibria; phase equilibria; liquid; binary; experimental data; calculated; phases; literature; model; calphad	The Cu-Tl-S system was studied by the EMF method with Cu4RbCl3I2 solid Cu+-conducting electrolyte within the temperature range from 300 to 390 K. The earlier plotted solid-phase equilibrium diagram of this system was confirmed, the partial copper molar functions (Delta(G) over bar, Delta(H) over bar, Delta(S) over bar) in alloys and standard thermodynamic formation functions and standard entropies of CuTlS2, CuTlS, Cu3TlS2, and Cu9TlS5 ternary compounds were calculated. The derived results demonstrated an opportunity of thermodynamic studies of copper-containing ternary systems of this modification by EMF method even if they contain a less noble component than copper.
10.1134-S1023193512010041	12	thermodynamic; ternary; phase; data; experimental; equilibria; phase equilibria; liquid; binary; experimental data; calculated; phases; literature; model; calphad	The EMF method with a solid Cu+-conducting electrolyte of Cu4RbCl3I2 was sued to study the Cu-Tl-Te system in the temperature range of 300-420 K. A diagram of solid-phase equilibriums of this system is constructed, partial molar functions of copper (Delta(G) over bar, Delta(H) over bar, Delta(S) over bar) in alloys, standard thermodynamic functions of formation and standard entropies of CuTlTe2, CuTl4Te3, Cu2TlTe2, Cu3TlTe2, Cu9TlTe5 triple compounds and CuxTl5 Te-x(3) solid solutions (0 < x < 1) are calculated. The obtained results confirmed the assumption as to the possibility of using this modification for the EMF technique for thermodynamic studies of copper-containing triple systems, even if they contain a less noble component than copper.
10.1134-S1027451011070226	-1		A new method is proposed for measuring the chemical composition of grain boundaries (GBs) in copper-based alloys not prone to embrittlement of boundaries. This method is based on embrittlement of copper GBs by bismuth penetrating from the gas phase of bismuth telluride (Bi2Te3). Chemical analysis of the GB surface is performed via Auger-electron spectroscopy. The GB composition is measured in a solid solution of silver (its volume concentration is 1.4 at%) and copper. The segregation annealing temperature is 570A degrees C. The silver concentration across the broken surface of the GB (its thickness is five to ten atomic layers) is 4.7 at%. Therefore, the ratio between silver concentrations within the GB and the grain volume (the enrichment coefficient) is approximately 3.5.
10.1134-S1063782617060069	-1		It is experimentally shown that the process of the solid-phase synthesis of copper silicide is sensitive to magnetic fields. Upon low-temperature vacuum annealing of a Cu/Si(100) thin-film structure, a static magnetic field with moderate strength stimulates the alloying of silicon in copper and suppresses synthesis of the Cu3Si phase.
10.1134-S1063783408110279	4	transformation; martensite; martensitic; phase; shape; beta; memory; shape memory; temperature; temperatures; martensitic transformation; gamma; transformation temperatures; effect; thermal	The generation and relaxation of reactive stresses in Cu-Al-Ni shape-memory alloy single crystals studied during a single cycle of temperature variation in the range 293-800 K under conditions of the beta-phase decomposition (above 600 K) are found to depend on the degree of beta-austenite decomposition at the stage of decreasing temperature. The higher this degree, the lower the stresses relaxed and generated upon decreasing temperature and the higher the critical temperatures of the reverse martensitic transitions. Moreover, loading the alloy by reactive stresses during a heating half-cycle causes not only a reversible martensitic shape memory deformation but also an additional austenitic shape memory deformation to occur when the temperature is decreased.
10.1134-S1063784209120123	9	magnetic; magnetization; magnetoresistance; temperature; superparamagnetic; annealing; gmr; field; magnetic properties; ferromagnetic; granular; samples; magnetic field; melt-spun; particles	The structure and magnetic properties of Cu-Fe fiber composites prepared by packet hydrostatic extrusion are studied. The number of armco-iron fibers in the copper matrix attained n similar to 8 x 10(10), and rated diameter d of fibers varied from 2 mm to 3 nm. A correlation is observed between the magnetization hysteresis curves and low-frequency magnetic susceptibility obtained on samples with various values of d. It is shown that the magnetic properties of composites in the submicrometer range of d values are satisfactorily described in the magnetization reversal theory for small ferromagnetic particles.
10.1134-S1063784218060178	-1		The functional properties of rod-shaped Cu-Al-Ni single-crystal alloy with the shape memory effect (SME) have been studied experimentally. Tensile tests of the samples have been carried out in the conditions imitating the operation of load-bearing elements in linear and rotary SME engines in the cyclic regime. Basic principles of constructing and the operating conditions of engines with load-bearing elements based on these single crystals have been formulated from the results of investigation. Basic relations between the functional properties of the single-crystal alloy and the main parameters of the engines have been established. Such characteristics as the maximal rod stroke in the linear engine and the angle of rotation of the shaft in the rotary engine, the maximal generated force and moment, as well as the effective work done by the engines, have been analyzed.
10.1134-S1063784220040040	6	grain; deformation; strain; strength; dislocation; cu-; tensile; size; ecap; grain size; sfe; ductility; hardening; high; stress	The experimentally found insensitivity of the resistivity of Cu-Cr and Cu-Cr-Zr alloys to structural modifications in alloy specimens subjected to severe plastic deformation has been studied by analytical modeling methods. Using Cu-1.8 wt% Cr-0.8 wt% Zr alloy as an example, it has been shown that an increased contribution of grain boundaries and secondary phase fine particles precipitated after equal channel angular pressing make an increased contribution to resistivity but this increase is compensated for by roughly the same decrease in the contribution from alloying atoms dissolved in the matrix.
10.1134-S1063784220070245	-1		Cu-14 wt% Al-4 wt% Ni alloy demonstrating the shape memory effect has been subjected to plastic deformation by means of uniaxial compression (upset). The process has been controlled by measuring the strain rate, applied stress, and compression ratio of standard specimens under isothermal conditions in the interval 400-600 degrees C. Structural modifications in the alloy after mechanical tests have been studied by optical, scanning, and transmission microscopy methods and using X-ray phase analysis. It has been found that grains in the alloy became much finer (from 1 mm to 100 mu m across) and its strength and ductility improved owing to dynamic recrystallization.
10.1134-S1063785019030118	4	transformation; martensite; martensitic; phase; shape; beta; memory; shape memory; temperature; temperatures; martensitic transformation; gamma; transformation temperatures; effect; thermal	We present the results of experimental studies of the return of Ni-Fe-Ga-Co and Cu-Al-Ni single crystals to the initial form at the macro- and microlevels after their deformation by compression and subsequent restorative heating. It is found that the geometric dimensions of the sample are reproduced with high accuracy (up to 20 m). The microrelief appearing on the initially polished surface during crystal compression (the arithmetic mean profile deviation R-a approximate to 0.25-0.75 m, the average spacing of local protrusions of the profile S approximate to 0.027-0.11 mm) is not removed by subsequent heating and remains with further multiple repetition of deformation-restoration cycles.
10.1134-S107042720905005X	4	transformation; martensite; martensitic; phase; shape; beta; memory; shape memory; temperature; temperatures; martensitic transformation; gamma; transformation temperatures; effect; thermal	Formation of solid solutions in the copper-gallium system under mechanical activation is considered as an example of a mechanochemical interaction between a solid metal and a liquid metal.
10.1134-S1070427217110222	2	corrosion; surface; film; electrochemical; films; spectroscopy; layer; current; solution; potential; resistance; composition; x-ray; ions; showed	Poly-2-(2,3-dimethylanilino) benzoic acid (PMF) coatings on copper and brass alloy were synthesized by electrochemical oxidation of 2-(2,3-dimethylanilino) benzoic acid in the presence of oxalic acid as the reaction medium. Electrodeposition was carried out using the cyclic voltammetry technique using a silver/silver-chloride standard electrode, with a scan rate of 600 mV min(-1). Smooth and well adhered PMF coatings were electrosynthesized during sequential scanning of the potential in the range -500 mV to 1400 mV on copper and brass alloy. The electrodeposited coatings were characterized by recording the oxidation peaks at 122 mV for Cu and -0.7 mV for brass, in cyclic voltammetry and using scanning electron microscopy (SEM). Corrosion inhibition efficiency of coated copper and brass alloy was investigated by electrochemical impedance spectroscopy (EIS) and potentiodynamic polarization techniques. The impedance results showed that the inhibition efficiency of coated copper is 89% and for coated brass 79.4% compared to the uncoated copper and brass in 0.1 M H2SO4.
10.1134-S1070427218040092	2	corrosion; surface; film; electrochemical; films; spectroscopy; layer; current; solution; potential; resistance; composition; x-ray; ions; showed	Methods of scanning electron microscopy, potentiodynamic polarization, and X-ray diffraction analysis were used to study the kinetic features of the electrodeposition process of the copper-tin alloy from an oxalic acid electrolyte and analyze the structure, composition, and luster of coatings formed under sonochemical treatment conditions at varied power of the ultrasonic field and current load. The ultrasonic treatment with power of 8-40 W dm(-3) makes it possible to 2-8 times intensify the cathodic process and obtain coatings containing 10-15 wt% tin with luster of 20-40%. The specific content of tin in a coating being formed is nearly independent of the ultrasound power and grows with increasing the cathodic current density.
10.1134-S1990793116060269	16	wear; composite; composites; powders; milling; particles; powder; wt; sliding; friction; hardness; matrix; mechanical; surface; properties	Nanostructured powders of pseudoalloys of immiscible Cu and Mo metals are prepared by highenergy ball milling (HEBM). Mechanical alloying in an Activator-2S planetary ball mill for 60 min provides a uniform distribution of refractory Mo particles in a moldable Cu matrix on submicron and nanoscopic levels. Nanostructured Cu-Mo powders are consolidated by spark plasma sintering (SPS) in a temperature range of 700-950A degrees C at a pressure of 50 MPa for 10 min. The effect of preparation conditions on the microstructure, crystal structure, and properties (density, hardness, electric resistivity) of the nanostructured Cu-Mo pseudoalloys is studied. It is shown that a combination of HEBM and SPS provides the formation of a high-density (97%) nanostructured consolidated Cu-Mo composite with a hardness of 3.68-3.88 GPa and an electric resistivity of 6.1-6.2 mu Omega cm; these parameters made the composite promising for use as an electric-contact material.
10.1134-S2070205117060028	-1		Physical vapor deposition method was utilized to apply Al coating onto Cu-10Al-13Mn alloy, then coated layer was anodized in different temperatures: 5 and 10A degrees C as well as several potentials: 20, 30, 40, 50 V in order to achieve best anodizing parameters. The effects of anodizing parameters on alumina nanotube formation and corrosion resistance were investigated. Phase analysis on surface was conducted by X-ray diffraction method and nanotube characteristics was studied by scanning electron microscopy (SEM) and surface topology was investigated by atomic force microscopy (AFM). Additionally, the corrosion resistance of coatings was studied by potentiodynamic test in 1M NaCl solution. The results depicted that whole deposited Al layer was anodized and FCC alumina was formed merely. Polarization test results was illustrated that Al anodized layer significantly improved Cu-10Al-13Mn corrosion resistance. Uncoated specimen had highest corrosion rate and anodized layer in lower temperature and voltage had minimum alumina nanotube dimension; as a result, it had best corrosion behavior in NaCl corrosive solution.
10.1139-cjc-2021-0228	-1		The arc melted and drop tube processed Cu-68.5 at. % Co alloy was subjected to differential thermal analysis (DTA). The liquidus temperature determined from the DTA curves of the arc melt sample (1664 K) was found to be close to the phase diagram estimate of 1662 K. In contrast, as a result of liquid phase separation in the drop-tube samples, the values obtained in the powders were much lower, mainly because the compositions of the demixed phases varied from those of the parent melt. The liquidus temperature of the 850+ lm powder was 1632 K, whereas that of the <38 lm sieve powder was 1616 K. This variance was due to the asymmetric nature of the metastable phase diagram of the system.
10.1139-cjp-2016-0926	-1		In the present study, a molecular dynamics simulation employing embedded atom method potential is performed to investigate the formation and characterization of CuZr bulk metallic glasses (BMGs). To elucidate the effect of component concentration of three samples of BMGs including Cu25Zr75, Cu50Zr50, and Cu75Zr25 that are formed by melt quenching. The local structure of BMGs is analyzed by means of radial distribution function and local atomic number density, rho. The mechanical behavior of three compositions is investigated using uniaxial compressive loading at a constant strain rate. It is revealed from the results that yield strength increases with increasing Cu concentration. Thermal expansion of CuZr BMGs is examined and variation in length and volume is measured. The analysis revealed that Cu25Zr75, and Cu50Zr50 exhibited the typical expansion behavior while Cu75Zr25 showed an anomalous behavior.
10.1139-tcsme-2018-0103	16	wear; composite; composites; powders; milling; particles; powder; wt; sliding; friction; hardness; matrix; mechanical; surface; properties	Copper alloys have important industrial roles due to their excellent properties. Beryllium copper is one of the copper-based alloys with the highest strength and excellent metal working and machining properties. Beryllium copper alloy composite is fabricated by the stir casting method. Its characteristics are studied with scanning electron microscopy and energy dispersive analysis of X-rays. The material properties of the stir cast beryllium copper alloy composites are evaluated. Hardness can be increased by the addition of silicon carbide particles. Abrasive water jet machining is an effective unconventional machining process, in which high pressure water jet and abrasive particles are used to remove material. Response parameters such as material removal rate and circularity of holes are considered. Response parameters of abrasive water jet machining are compared to electrical discharge machining. The most influential factor for the responses is determined by analysis of variance. Optimization of machining parameters is performed with the Taguchi method.
10.1140-epjb-s10051-021-00094-y	-1		In this paper, we propose a new theoretical approach that combines classical MD method and a one-dimensional diffusion model. We have shown that our approach allows to extrapolate the results of MD simulations to the experimental timescale. As an example, the formation of Cu-Pt nanocontacts in the STM-BJ experiments was investigated. STM-BJ simulations with copper STM tips and Cu-Pt surface alloys were performed in a wide range of temperatures (300-900 K), number of Pt atoms in the substrate (1-7) and for different orientations ((100), (110) and (111)) of the STM tip. Using our approach, we predicted that it is possible to use the STM-BJ technique to prepare Cu-Pt nanocontacts. The presented approach should work well in all cases when the diffusion of atoms occurs via interlayer jumps. Graphic abstract
10.1140-epjp-s13360-022-03405-z	-1		The high-temperature oxidation behavior of a Cu-2.1Be commercial alloy was studied. Samples subjected to oxidation treatments for 17 h at 850 degrees C in air were characterized by gravimetric and hardness measurements, Raman microspectroscopy and LIES measurements. The corrosion products formed on the surface of the samples oxidized for 17 h at 850 degrees C in air consisted of BeO and copper oxides. From the in-depth characterization obtained by LIES, it was found that the oxide film would be of around 40 mu m, with an outermost layer richer in beryllium compared to the inner layer. In the bulk of the alloy, a diffusion gradient of beryllium was observed in the region closest to the interface with the oxide film, with an outer layer richer in beryllium. The hardness decreases from 93 HV to around 84 HV after five oxidation treatments in samples subjected to oxidations of 17 h at 850 degrees C and polished. This decrease would be associated with the growth of the grain size due to the oxidation treatment and the loss of beryllium from the alloy due to the formation of the corrosion products. However, the loss of beryllium is not large enough to affect the formation of gamma' precipitates.
10.1140-epjp-s13360-025-06802-2	14	strength; properties; conductivity; electrical; mechanical; cu-; grain; mpa; electrical conductivity; aging; precipitation; phase; mechanical properties; tensile; phases	This study systematically evaluates the radiation shielding performance of ternary Cu-Zn-Al alloys against gamma rays, beta particles, and neutrons for nuclear, medical, and aerospace applications. Seven alloys with varied Zn and Al contents were produced by arc melting and analyzed using Phy-X/PSD, NGCal, and NIST ESTAR. For 0.662 MeV gamma rays, Cu70Zn2Al28 (A7) showed the highest mass attenuation coefficient (0.0731 cm2/g), indicating suitability for lightweight shielding. Cu70Zn28Al2 (A1) delivered the highest linear attenuation coefficient (0.5061 cm(-)1), the shortest mean free path (1.97 cm), and the lowest half-value layer (1.369 cm), enabling compact, high-efficiency gamma attenuation. For beta radiation, A1 provided the best overall stopping power by balancing collisional and radiative losses, while A7 exhibited superior radiative stopping power at higher energies, favorable for specific industrial uses. Neutron analyses identified A1 as the top performer, with the highest linear attenuation coefficients for thermal (0.2216 cm(-)1) and fast (0.0268 cm(-)1) neutrons, along with short mean free paths and half-value layers. In conclusion, Cu-Zn-Al alloys offer tunable, multifunctional radiation protection, with A7 preferred for weight-sensitive applications and A1 for compact, high-performance shielding, informing the design of advanced, nontoxic, mechanically robust materials.
10.1142-S0217979210064435	-1		The paper is focused on the wear mechanism of orbital forged and equal-channel angular extruded Cu OFHC (oxygen-free high thermal conductivity) material. The wear behaviour of the Cu OFHC material is investigated through pin-on-disc tests. Two different processing conditions have been used, equal-channel angular processing (ECAP) and orbital (radial) forging. The wear investigations in this orbital formed material are unique; additionally wear properties show interesting wear characteristics. Particular attention has also been paid to the friction coefficient and to the role of the wear rate.
10.1142-S0217984921505102	15	aging; strength; conductivity; electrical conductivity; electrical; mpa; treatment; strengthening; degrees; cu-; cold; precipitation; tensile strength; tensile; iacs	The metallic element Mo has almost no solid solubility in copper and can be used as a nucleation particle to refine the grain size and increase the recrystallization temperature of the alloy during solidification. It is expected to obtain copper alloys with good comprehensive properties by reasonably controlling the addition amount of Mo. However, it is difficult to prepare Cu-Mo alloys with uniform structure and there are few related literatures. In this paper, the aluminothermic reaction method, which has the advantages of simple process, low cost, and large size of the prepared alloy, was adopted, and a cluster model with the atomic ratio of Mo and Ni of 1:12 was introduced to design the alloy composition. Here, five alloys with different copper contents were prepared and followed by room temperature rolling with 40%, 60%, and 80% deformation. The results show that the as-cast Cu-Ni-Mo alloys exhibit good formability, have no macroscopic defects and present a small amount of precipitates. With the increase of alloy elements Ni and Mo, the hardness and strength of the alloys increase obviously, while the electrical conductivity decreases gradually. For the rolled alloys, a large number of lamellar deformed structures are formed, the grains are obviously refined, the precipitated phases are broken and the distribution is more uniform, thus the strength and hardness of the alloy increase significantly, the plasticity decrease significantly, while the conductivity changed little. In this study, high-strength samples were obtained, which may be a valuable exploration for the preparation of Cu-Ni-Mo alloy sheets with excellent microstructure and mechanical properties.
10.1142-S0218625X96002746	-1		Three different experimental approaches have been developed to study the dynamic process of subsurface altered layer formation in a Cu-Pt alloy under Ar+ ion bombardment: (1) sputter neutral mass spectrometry by multiphoton ionization (MPI-SNMS) for the study of preferential sputtering caused by the collision cascade process in the very initial stage of sputtering; (2) ion scattering spectroscopy (ISS)-Auger electron spectroscopy (AES) sequential measurements for investigating radiation-enhanced Gibbsian segregation in the transient stage of sputtering; (3) an approach based on ISS monitoring by prompt switching of the ion bombardment with (He+ + Ar+) ions to that with He+ ions, for revealing the cooling effect in radiation-enhanced diffusion in the final steady state of sputtering. For this we have developed a specific coevaporating device for depositing Cu and Pt simultaneously on a substrate at constant deposition rate. The coevaporating device was attached to both of the specimen chambers of the Auger microprobe, JAMP-3, and of the MPI-SNMS apparatus. The results have clearly revealed: (i) ion bombardment causes a preferential sputtering of Cu atoms in the very initial stage of sputtering, (ii) followed by gradual formation of an altered layer as ion sputtering proceeds in the transient stage, and (iii) finally the alloy system approaches a steady state where the composition profile is controlled by cascade mixing, radiation-enhanced Gibbsian segregation and radiation-enhanced diffusion to satisfy the mass balance law. In the steady state the approach (3) has, first, revealed that the cooling effect does exist in radiation-enhanced diffusion.
10.1142-S1793604712500087	4	transformation; martensite; martensitic; phase; shape; beta; memory; shape memory; temperature; temperatures; martensitic transformation; gamma; transformation temperatures; effect; thermal	Guaranteed behavior of SMA in damping needs deep study of the alloy behavior according to the requirements. Pseudoelastic window, evolution of properties, self-heating and fatigue are the major concerns. The analysis shows that selected alloys can do the work. The application to portico and to cable oscillations in realistic systems shows an excellent damping effect. Useful simulation requires a good phenomenological model. A cubic model is built with improved results at low deformation.
10.1143-JJAP.39.6067	2	corrosion; surface; film; electrochemical; films; spectroscopy; layer; current; solution; potential; resistance; composition; x-ray; ions; showed	Electrodeposits of 80Sn-20Pb were formed on a Cu-based leadframe alloy from organic sulfonate solutions under different plating conditions, and were then aged at 100 to 180 degreesC to examine the effects of the microstructure of electrodeposits on the growth kinetics of the Cu-Sn intermetallic layer formed at the electrodeposit/substrate interface? and the resultant influence on the fracture resistance of the electrodeposits under bending. The Cu-Sn intermetallic compound layers [epsilon (Cu-3 Sn) + eta (Cu6Sn5)] increase linearly in thickness with the square root of aging time. However, the growth rate of the intermetallic compounds layer exhibits significant differences depending on the deposition condition. it is fastest in an extremely fine elecrodeposit formed using pulse current in a bath without any grain refiner, but is slowest in that formed using de current in a bath with grain refiner, in spite of an equivalent grain size in both electrodeposits. This is due primarily to the inhibiting effects of the grain refiner remaining at grain boundaries of the electrodeposit on the diffusion of Sn across the intermetallic compounds/electrodeposit interface. The occurrence frequency and the degree of opening of surface cracks, formed when the aged samples are subjected to the 90 degrees -bending test, are found to be associated with the growth rate of the intermetallic compound layer and the ductility of the electrodeposit For samples aged under the same conditions, the sample electrodeposited from the solution containing grain refiner shows the highest resistance to surface cracking during the 90 degrees -bending test due to the lower growth rate of its intermetallic layer and the higher ductility of the electrodeposit compared with those of other samples.
10.1143-JJAP.39.L119	-1		The newly developed cable used for a robot was shown to have its excellent durability against cyclic and flexural deformation, when composed of in situ-formed metallic-fiber-reinforced copper matrix composites (in situ MMCs) as electric conductors, where the metallic fiber was, for example, niobium or chromium, The durability determined by a cyclic and flexural deformation test was one order magnitude higher than that of a conventional cable whose electric conductor was composed of a Cu-0.3 mass%Sn alloy. A noteworthy feature observed in the present in situ-formed chromium fiber is that the mean size of the formed chromium ribbon like fiber was below 1.0 mu m in width and around 10 nm in thickness, which could result in an extremely high elastic limit of beyond 1000 MPa. The superior durability of the present robot cable is mainly due to the fact that robot operations are in the elastic region of the present electric conductors. The electric conductivity of samples was around 70%IACS (International Annealed Copper Standard).
10.1143-JJAP.49.075804	-1		We investigated a method of producing low-resistivity and adhesive sputter-deposited copper alloy films with an intermediate oxide layer that retains its adhesion after hydrogen annealing for applications of electric interconnections for thin film circuits and liquid crystal displays. The formation of an intermediate copper oxide layer between a copper film and a substrate by sputter deposition in the presence of oxygen enhances adhesion. However, when such films are exposed to hydrogen at elevated temperatures, hydrogen penetrates the films and reduces copper oxide. This reaction generates water molecules, which aggregate at the interface between the copper film and the substrate. As a result, microvoids form at the interface, degrading the film adhesion. Sputter-deposited films with an intermediate oxide layer produced from a Cu-Ca target are adhesive even after hydrogen annealing. As films deposited in pure argon have low resistivities, it is possible to form low-resistivity and adhesive metallization. (C) 2010 The Japan Society of Applied Physics
10.1143-JJAP.51.01AK01	16	wear; composite; composites; powders; milling; particles; powder; wt; sliding; friction; hardness; matrix; mechanical; surface; properties	Solid particles in discontinuous reinforcement metal matrix composites (DRMMCs) drastically improve their strength . Since the strength of DRMMCs is improved by the Orowan mechanism, smaller particles, such as nanoparticles, are effective as dispersoids. In this study, the effects of nanoparticles on the sliding wear behavior of DRMMCs are investigated using Cu-based composites containing 0.6, 1.2, and 1.7 vol% SiO2 particles. Wear resistance of the Cu-SiO2 composite is improved by increasing the volume fraction of SiO2 particles. Moreover, the amount of wear for the Cu SiO2 composites increases with increasing sliding distance and then becomes saturated beyond about 1000 m. Vickers hardness for all specimens becomes the same regardless of the volume fraction of SiO2 particles as the sliding distance increases. This behavior can be explained by the work-hardening rate of the Cu matrix and the critical hardness for adhesion with a counter-material. It is found that nanoparticles in DRMMCs improve wear resistance by increasing the work-hardening rate of the metal matrix. (C) 2012 The Japan Society of Applied Physics
10.1143-JPSJ.79.064603	-1		A relative stability of solid solutions versus amorphous phases in the Cu-Ti system has been studied by molecular dynamics simulations using an n-body potential. The simulations have shown that for the CuxTi100-x alloys, a spontaneous crystalline to amorphous transition takes place in the central composition region and that the energy of amorphous phases is lower than the solid solutions at 22 <= x <= 71 at. % owing to a fast energy drop of the former than the latter, in accordance with the thermodynamics analysis and experimental results. The detailed structural analysis showed that for the Cu-rich side, with increasing the Ti concentration, both the total average coordination number and the short range order chemically favoring unlike bonds are better allowed and more pronounced in the amorphous state than in the fcc solid solution. Therefore, the relative stability of both phases revealed by difference of energy is correlated with the structure change of the amorphous phase.
10.1149-1.1394099	2	corrosion; surface; film; electrochemical; films; spectroscopy; layer; current; solution; potential; resistance; composition; x-ray; ions; showed	The electrodeposition of Cu on zinc alloy diecast from a cyanide bath was studied using electrochemical techniques and scanning tunneling microscopy (STM) imaging. As the current density ii) is changed from 1 to 30 mA cm(-2), the root mean square roughness of the deposit (xi) first increases, reaching a maximum value at j = 10 mA cm(-2), and then decreases. This behavior is explained by the strong interference of the hydrogen evolution reaction at the highest current densities. The dynamic scaling theory applied to the STM images for the advanced stages of Cu electrodeposition obtained at j = 10 mA cm(-2) leads to a roughness exponent a = 0.80 and growth exponent beta > 0.5 consistent with an unstable interface evolution. The addition of sodium selenite promotes a leveling effect by hindering the growth of instabilities, leading to an interface evolution consistent with the predictions of thr Edwards-Wilkinson growth model.
10.1149-1.1481718	2	corrosion; surface; film; electrochemical; films; spectroscopy; layer; current; solution; potential; resistance; composition; x-ray; ions; showed	Thin films of Cu-Co alloy exhibiting excellent metallic luster were galvanostatically electrodeposited directly on Si substrates in a single citrate bath containing sulfates of the metal ions. The direct electrodeposition onto n-Si substrates eliminated a processing step, of depositing a conducting layer, if an insulator were to be used as a substrate. In addition, the use of silicon as a substrate is promising in integrating this inexpensive technique with semiconductor microelectronic device fabrication technology. The as-deposited films exhibited giant magnetoresistance (GMR) of 1% (T = 300 K, H = 10 kOe) and 5% (T = 10 K and H = 50 kOe). The annealed films showed an increase in GMR from 1 to 2.7%. The X-ray diffraction studies of as-deposited metastable films indicate solid solution like behavior following Vegard's law. However, our magnetic studies evidenced the presence of very fine nanograins of Co in these films. A systematic study of the effect of various processing parameters like deposition current density, bath temperature, and pH on the composition, structure, and microstructure of thin films was carried out to understand the electrodeposition process. Deposition current density and bath temperature have significant control over the composition and microstructure. The pH of the electrolyte seems to affect the topography most. Like physical vapor deposition (PVD), the electrodeposition process yields thin films via a nucleation-controlled growth mechanism. The superiority of the electrodeposition technique over the PVD technique is emphasized. (C) 2002 The Electrochemical Society.
10.1149-1.2207840	2	corrosion; surface; film; electrochemical; films; spectroscopy; layer; current; solution; potential; resistance; composition; x-ray; ions; showed	The electrodeposition of Cu-gamma-Al2O3 nanocomposites as thin films and into recessed electrodes prepared with X-ray lithography was examined in ammonia-citrate electrolytes. Partial current density, current efficiency and deposit particle concentration were determined with a rotating disk electrode. At pH 8 the presence of particles resulted in an enhancement of the Cu reaction rate, while at pH 10 the reaction rate appeared inhibited. The amount of particles in the deposit and current efficiency was larger for pH 8 than pH 10, rendering the pH 8 solution a more promising electrolyte to electrodeposit 500 mu m deep recesses for MEMS composite components. (c) 2006 The Electrochemical Society.
10.1149-1.2832428	2	corrosion; surface; film; electrochemical; films; spectroscopy; layer; current; solution; potential; resistance; composition; x-ray; ions; showed	Sulfide-induced intergranular corrosion (IGC) of copper was documented in salt water under free corrosion or controlled potential. The process was promoted by the oxidizing potential and the sulfide ions. A transition potential, E-t, of about -0.15 V (Ag/AgCl) was identified in the polarization curves in the presence of sulfide ions. Above E-t, sulfide ions accelerate IGC while having a modest effect on the rate of copper dissolution. Below E-t, they promote copper dissolution, while IGC occurs much more slowly. Various sulfur species were detected in the corrosion product using X-ray photoelectron spectroscopy.
10.1149-1.2946709	-1		Electrodeposition of Cu-Ni thin films can result in phase separation characterized by the formation of nodular features that exhibit a uniform columnar core/shell structure with a copper-rich core and nickel-rich shell. Here, we show that the core/shell microstructure is the result of differences in the nucleation and growth rates of the two components. In the potential range where the core/shell structure is observed, copper deposition is fast, resulting in the formation of a relatively low density of large hemispherical islands. Nickel deposition is characterized by slower kinetics, resulting in the formation of a high density of small islands surrounding the copper islands. These results provide a basis for understanding the formation of this core/shell microstructure in binary alloy systems. (C) 2008 The Electrochemical Society.
10.1149-1.3463718	2	corrosion; surface; film; electrochemical; films; spectroscopy; layer; current; solution; potential; resistance; composition; x-ray; ions; showed	The influence of the benzotriazole (BTAH) inhibitor on the thickness of the Cu2O oxide layer formed on Cu immersed in 3% NaCl solution was studied with angle-resolved X-ray photoelectron spectroscopy. The X-ray-induced Auger Cu L3M4,5M4,5 spectra were reconstructed with the Monte Carlo algorithm using the spectra of the basic constituents [Cu(I)BTA, Cu2O, and Cu] formed on the surface. The relative contributions of the basic constituents to the composite Cu L3M4,5M4,5 spectra measured at different emission angles were then used to estimate the thickness of the Cu2O oxide layer. The results show that the presence of BTAH substantially reduces the thickness of the Cu2O oxide layer formed on Cu in chloride media. The average thickness of the Cu2O layer below the Cu(I)BTA layer is estimated to be 1.3 +/- 0.2 nm, whereas the Cu2O thickness of the noninhibited sample is 2.2 +/- 0.3 nm.
10.1149-1945-7111-aba15f	2	corrosion; surface; film; electrochemical; films; spectroscopy; layer; current; solution; potential; resistance; composition; x-ray; ions; showed	In this study, we explored the possibility of synthesizing Cu-As alloys from copper electrolyte by a controllable electroplating method. The effects of electrochemical potential, copper to arsenic molar ratio, as well as the addition of EDTA, on the electroplating of Cu-As alloys from the simulated electrolyte containing copper and arsenic, were investigated. XRD and SEM/EDS were utilized to characterize the synthesized Cu-As alloys produced from each test. It was found that the decrease of electrodeposition potential and copper concentration can lead to the formation of copper arsenide intermediate phases, which bring about phase transitions of the alloy from Cu to Cu3As and then to Cu5As2. It was also discovered that the alloy electrodeposited in EDTA-contained electrolyte presents a plate morphology, with Cu-As phases dispersedly distributed on the copper base. The synthesized Cu-As alloys with such phase structure present a superior corrosion resistance.
10.1149-1945-7111-ac0f60	-1		Historically, there have been two general approaches for understanding alloy passivation behavior. One involves study of the composition and crystal structure of the passive film and the other is concerned with how the composition and structure of the metallic alloy dictates the formation of the film. Herein we describe a recently developed theory based on a conjecture of Sieradzki and Newman connected to percolation theory and use the theory to model the passivation behavior of a series of Cu-Rh alloys. Our results are in quantitative agreement with the predictions of this theory. We discuss how the theory elucidates the important role of short-range order in understanding how composition affects the details of the passivation process.
10.1149-1945-7111-ac78d3	2	corrosion; surface; film; electrochemical; films; spectroscopy; layer; current; solution; potential; resistance; composition; x-ray; ions; showed	Under some conditions, copper and copper alloys are either immune from corrosion or undergo slow uniform corrosion, generally considered a favourable situation, since predicting the damage incurred by the metal during a period of uniform corrosion is relatively straightforward. However, under conditions leading to surface passivation of Cu, localized corrosion might occur in the presence of aggressive oxidants. Therefore, the susceptibility of Cu to localized corrosion must be considered carefully to avoid unpredictable failures in Cu-based structures. Understanding the pitting probability of Cu is important for various applications, including the use of Cu-coated containers for the permanent disposal of used nuclear fuel. In this study, the pitting probability of Cu in chloride-containing solutions crudely representing the groundwater that might be found in a deep geologic repository (DGR) was investigated using electrochemical techniques and statistical analysis. The probabilities of both pitting and repassivation of Cu were found to increase with increasing [Cl-]. The surface morphologies of copper electrodes in the same solution were also evaluated using scanning electron microscopy (SEM). The passive film on the surface of the copper electrode with the highest breakdown potential (E-b) was found to be more protective than that on the electrode with the lowest E-b.
10.1149-1945-7111-ae0eb6	-1		The influence of Sn alloying additions on the aqueous passivation behavior of Cu-Al alloys was revisited and found to function as a new third element effect in acidified 0.1 M Na2SO4 solution. The role of each element during the process of aqueous passivation was investigated using electrochemical and surface-sensitive ex-situ and in-operando spectroscopic techniques. The connection between passivation and the atomic arrangements of atoms in the solid solution was supported by first principles' based cluster expansion calculations and Monte Carlo simulations probing the chemical short-range order in the Cu-Al-Sn system. High purity Sn, like high purity Cu, did not passivate in the test environment, whereas high purity Al formed a passive film with a stable passive current density of 0.01 mA cm(-2). Cu-xAl-Sn solid solution alloys where x > 18 at%, containing less than 3 at% Sn additions exhibited lower corrosion rates than Cu-xAl alloys, brought by Al(III) and Sn(IV, II) unidentified complex oxides on the surface. A strong influence of Sn on Al(III) passivation was observed, i.e., suggesting a third element effect type behavior. Possible governing processes explaining the stainless steel type corrosion behavior are discussed, providing insights for exploring novel synergies in the design of corrosion resistant alloys. (c) 2025 The Author(s). Published on behalf of The Electrochemical Society by IOP Publishing Limited. This is an open access article distributed under the terms of the Creative Commons Attribution 4.0 License (CC BY, https://creativecommons.org/licenses/ by/4.0/), which permits unrestricted reuse of the work in any medium, provided the original work is properly cited.
10.1149-2.004401eel	-1		A ternary Cu-Hf-Al amorphous thin film with excellent corrosion resistance was successfully synthesized using DC magnetron sputtering method. Electrochemical behaviors of the Cu-Hf-Al films have been studied in four different corrosive media (NaCl, KCl, Na2SO4, and H2SO4 solutions). According to the annealed samples' X-ray diffraction (XRD) pattern we found that the glass transition temperature T-g of the Cu-Hf-Al amorphous film is around 580 degrees C. Distinct polarization behaviors were found for the film in 1 mol/L H2SO4 and 0.5 mol/L Na2SO4 solutions. The as-synthesized films exhibit much higher corrosion resistance in H+ or Na+ environments than in Cl-environments. In Cl-containing solutions the films also show distinct spontaneous passivation although they suffer pitting by anodic polarization. Annealing was also found to affect the electrochemical behaviors of the amorphous films. The samples annealed at 600 and 700 degrees C showed complete passive behavior in the polarization curves and their passivity was broken gradually.
10.1149-2.013406eel	2	corrosion; surface; film; electrochemical; films; spectroscopy; layer; current; solution; potential; resistance; composition; x-ray; ions; showed	Codeposition of copper and molybdenum was obtained by electroplating using CuSO4 and Na2MoO4 with trisodium citrate as complexing agent. The molybdenum content which was investigated by inductively coupled plasma atomic emission spectroscopy in electroplated Cu-Mo increased, from 0.5 to 7.1 wt%, with decreasing current density in the range from 0.1 to 1.2 A/dm(2) during electroplating. X-ray diffraction showed that the structure of molybdenum is amorphous, and higher molybdenum content gave smaller and wider Cu (111) peaks, furthermore, made the surface morphology smoother. These suggest that molybdenum atoms are introduced into copper crystal lattices, resulting in breaking copper crystal lattices.
10.1149-2.0221501jes	2	corrosion; surface; film; electrochemical; films; spectroscopy; layer; current; solution; potential; resistance; composition; x-ray; ions; showed	Copper (Cu) nanofilms have been prepared on a molybdenum (Mo) substrate by the electrodeposition method from the electrolyte solutions of copper sulfate (CuSO4) and trisodium citrate (C6H5Na3O7) added by surfactant PEG-6000. The growth kinetics and microstructures of films were investigated by cyclic voltammetry (CV), chronoamperometry (CA), scanning electron microscopy (SEM) and atomic force microscopy (AFM). Cyclic voltammetry and chronoamperometry clearly show that the electrodeposition is controlled by the diffusion process of copper ions. By means of Scharifker-Hills model, the Cu nucleation mechanism in 0.1mol/l CuSO4 and 0.2 mol/l C6H5Na3O7 solution is revealed to be an instantaneous nucleation. Potential, solution concentration and organic additive have an influence on the microstructure of copper film. SEM and AFM results show a uniform copper layer with 7.7 nm roughness can be fabricated when deposition charge quantity is 0.7 C/cm(2) at -0.7 V vs SCE.
10.1149-2.0501908jes	2	corrosion; surface; film; electrochemical; films; spectroscopy; layer; current; solution; potential; resistance; composition; x-ray; ions; showed	Cu-Zn alloy micropillars were fabricated by a potentiostatic localized electrochemical deposition (LECD) process. This process was carried out via micro-anode-guided electroplating in a pyrophosphate bath at a constant negative potential in the range -1.85 to -2.05 V. Different products were produced, depending on the initial inter-electrode gap employed. Thus, at an initial gap of 40 mu m, the process afforded micropillars with a single alpha-brass crystal phase and at% Zn contents in the range 17.20-32.01%. A reduction in the initial gap to 30 mu mresulted in varied micropillar crystal phases (alpha, beta, and beta + beta') with at% Zn contents in the range 37.12-68.94. The simulation commercial software COMSOL 5.2 was employed to correlate the asymmetric distribution of the electric field to the experimental parameters and pillar characteristics. The resultant data was then used to delineate the dependence of the field strength on the crystal phase, composition, growth rate, and micropillar diameters. Finally, a potentiodynamic cathodic polarization study was employed to elucidate the mechanism for the fabrication of the Cu-Zn alloy micropillars via potentiostatic LECD. (C) 2019 The Electrochemical Society.
10.1149-2.0631816jes	-1		Electrochemical dealloying of Cu- Rh alloys was systematically studied in 1 M H2SO4 aqueous solution in order to clarify the effect of Rh oxide passivation on dealloying behavior. Active dealloying, oxide passivation and transpassive dealloying regions were consecutively identified in their anodic polarization curves. The dealloying is rapid in both active and transpassive regions. The active dealloying region vanishes as Cu content decreases to below 85 at%. When the Cu content is further decreased to below 75 at%, the transpassive dealloying also ceases and the material becomes stainless. This indicates that the parting limit for the dealloying of Cu-Rh is located at similar to 75 at%, which is much higher than that of Au-Ag and other alloys that do not involve oxide passivation in dealloying. The high parting limit for Cu-Rh is associated with a passive layer of Rh oxide formed by corrosion, which hinders dealloying and nanoporosity evolution processes. The parting limit identified here may be an extrinsic property. The intrinsic parting limit of this alloy, i.e., the threshold composition below which the dealloying is hindered by a passive layer of Rh (instead of oxide passivation), could be lower-it may be obtained by avoiding any form of oxide passivation in corrosion. Moreover, all dealloyed nanoporous Rh shows a face centered cubic crystal structure, in contrast to the hexagonal close packed structure reported in Rh nanoparticles. (c) The Author(s) 2018. Published by ECS.
10.1149-2.0691608jes	2	corrosion; surface; film; electrochemical; films; spectroscopy; layer; current; solution; potential; resistance; composition; x-ray; ions; showed	In this research, a nanostructured copper surface was fabricated using a CuSO4 center dot 5H(2)O solution containing boric acid. Cu and Cu2O structures simultaneously formed when the electrodeposition was performed using the CuSO4 center dot 5H(2)O solution. The Cu deposition ratio increased when the concentration of CuSO4 center dot 5H(2)O decreased or the applied current density increased. In contrast, the Cu2O deposition ratio increased when the concentration of CuSO4 center dot 5H(2)O increased or the applied current density decreased. A nanoplate-type Cu structure or octahedral Cu2O structure formed when boric acid was added to the CuSO4 center dot 5H(2)O solution. When the concentration of the added boric acid was 2.0 M and the applied current density was above 70 mA/cm(2), high-density nanoplates or dendrite structures were formed. In addition, the fabricated samples showed superhydrophobic properties under these conditions after hydrophobic layer coating. The proposed copper electrodeposition methods can be applied to various industrial fields that require metal nanostructures.
10.1149-2.0691902jes	2	corrosion; surface; film; electrochemical; films; spectroscopy; layer; current; solution; potential; resistance; composition; x-ray; ions; showed	Glutamate is a potential replacement of cyanide in alkaline electrolytes due to its capability to form complexes with bivalent metal ions. Since promising results were achieved with copper and zinc plating baths, and the use of cyanide implies environmental and safety disadvantages, it was decided to study the possibility of codepositing these two metals using sodium glutamate as complexing agent. Electrochemical processes involved in electrodeposition of copper and zinc individually as well as in solutions containing both metal ions were studied utilising cyclic voltammetry. Cu-Zn deposits obtained at different current densities from solutions of different composition were characterized by SEM and EDS. It was concluded that the system has a normal behavior, according to Brenner's classification, since the more noble metal is deposited preferentially. The plating bath containing 30% molar of Cu2+ was selected to continue the studies of the system. (C) 2019 The Electrochemical Society.
10.1149-2.0721908jes	2	corrosion; surface; film; electrochemical; films; spectroscopy; layer; current; solution; potential; resistance; composition; x-ray; ions; showed	In this paper we report on electrodeposition of CuNi alloys with low Ni content for applications in three-dimensional stacking of integrated circuits (SIC). For practical reasons related to compatibility with SIC processing, a common sulfate-based electrolyte solution was chosen and the high copper/low nickel content in the deposited alloys was achieved through the introduction of organic additive benzotriazole (BTA). BTA is known as a strong inhibitor for Cu deposition, but its effects on CuNi alloy deposition were not known before. We hypothesized that, in addition to bringing the onset potential of Cu closer to that of Ni deposition, the slower diffusion through the BTA passivation layer could enable improved control of the composition of the deposited alloy as well as the current distribution over the substrate. Our hypotheses were tested through systematic electrochemical measurements combined with ex-situ imaging and chemical analysis techniques. As such, CuNi alloys with Ni content between 5-15 at% were successfully fabricated from a sulfate-based CuNi electrolyte solution with BTA as an organic additive. (C) The Author(s) 2019. Published by ECS.
10.1149-2.0731813jes	2	corrosion; surface; film; electrochemical; films; spectroscopy; layer; current; solution; potential; resistance; composition; x-ray; ions; showed	Integrated circuits currently use mainly copper as the interconnect material; unfortunately the ongoing miniaturization currently requires materials with higher electromigration resistance and possibly improved conductivity. In this context we report on the structure, microstructure and electrical properties of a series of Cu-Ge(O) alloy films, electrodeposited from an alkaline tartrate electrolyte. The composition of the films varies between zero and 20 at% Ge, with a significant incorporation of oxygen. Film morphology is dense and uniform, with Cu-Ge films exhibiting smaller apparent grain size (similar to 50 nm) with respect to Cu films grown from a similar electrolyte. Solid solutions and phase mixtures of a solid solution with the intermetallic are observed with increasing Ge fraction; the presence of intermetallic phases is confirmed by TEM imaging and diffraction. The resistivity of 50 nm thick films follows the published trend, with a slight increase of the value upon solid solution formation and a minimum in correspondence of the intermetallic composition. Thicker films (similar to 1 um) on the other hand show a different trend, with resistivity increasing with Ge and O at%; in this case the resistivity is probably dominated by the oxygen incorporation. (C) The Author(s) 2018. Published by ECS.
10.1149-2.1301810jes	2	corrosion; surface; film; electrochemical; films; spectroscopy; layer; current; solution; potential; resistance; composition; x-ray; ions; showed	Frequently-touched surfaces are a common transmission source for hospital and community acquired infections. Cu alloys have shown promise as antimicrobial surfaces, able to kill even antibiotic-resistant bacteria within minutes. However, the most efficacious alloy systems readily tarnish making them unsuitable for hospital applications and tarnish-resistant (e.g., passive) systems often cannot maintain sufficient Cu ion release to maintain antimicrobial function. An ideal alloy would have optimal corrosion, tarnishing, and Cu release tuned through alloying elements. Cu-Al alloys are tarnish-resistant, yet the precise role of Al remains unclear. Highpurity binary alloys of Cu-Al were fully immersed in artificial perspiration at open circuit to evaluate soluble cation release, quantity and identity of corrosion products, as well as interrogate the role of Al on the chemical, structural, and electronic defect structure of oxides formed. Al became captured in Cu2O as a substitutional cation defect which in turn caused structural, and electronic modifications. This doped film did not inhibit soluble Cu cation release for antimicrobial function even after 144 h . Al-doped cuprous oxide had fewer electronic charge carriers (holes) due to Al-doping and subsequent increased electronic resistance. These results are promising regarding the aim of generating a tunable tarnish-resistant layer for an antimicrobial Cu-based alloy. (C) The Author(s) 2018. Published by ECS.
10.1155-2013-502150	-1		Monoclinic Cux+yBi5-ySe8 structure has multiple disorders, such as randomly distributed substitutional and interstitial disorders by Cu as well as asymmetrical disorders by Se. Herein, we report the correlation of electronic and thermal properties with the structural complexities of Cux+yBi5-ySe8. It is found that the interstitial Cu site plays an important role not only to increase the electrical conductivity due to the generation of electron carriers but also to reduce the thermal conductivity mainly due to the phonon scattering by mass fluctuation. With impurity doping at the interstitial Cu site, an extremely low lattice thermal conductivity of 0.32 W.m(-1).K-1 was achieved at 560 K. These synergetic effects result in the enhanced dimensionless figure of merit (ZT).
10.1155-2014-160580	16	wear; composite; composites; powders; milling; particles; powder; wt; sliding; friction; hardness; matrix; mechanical; surface; properties	An in situ Cu-NbC composite was successfully synthesized from Cu, Nb, and C powders using ball milling and high pressure torsion (HPT) techniques. The novelty of the new approach, HPT, is the combination of high compaction pressure and large shear strain to simultaneously refine, synthesize, and consolidate composite powders at room temperature. The HPTed Cu-NbC composite was formed within a short duration of 20 min without Fe contamination from the HPT's die. High porosity of 3-9%, Fe and niobium oxidations, from grinding media and ethanol during ball milling led to low electrical conductivity of the milled Cu-NbC composite. The electrical conductivity of the HPTed Cu-NbC composite showed a value 50% higher than that of milled Cu-NbC composite of the same composition.
10.1155-2017-7536853	-1		The viscosity and liquid structure of Cu100-xSnx(x = 10, 20, 30, 40, at%) melts were investigated. Temperature dependence of viscosity eta and correlation length D all shows an exponential decay function (Arrhenius-type equation), which is similar to our former studied Cu-Ag alloys. The correlation between viscosity and liquid structure had been studied. A simple relation between viscosity and correlation length D was found. The ratio of D and eta shows a linear relationship with temperature, which is different fromour former studied results in Cu-Ag alloys. Among the four Cu-Sn alloys, Cu80Sn20 and Cu-70 Sn-30 alloys have higher activation energy for viscous flow (E-a,E-V), activation energy for structural evolution (E-a,E-D), and the slope (gamma) of the linear relationship of D/eta with temperature due to the Cu3Sn clusters formation.
10.1155-2018-3653987	15	aging; strength; conductivity; electrical conductivity; electrical; mpa; treatment; strengthening; degrees; cu-; cold; precipitation; tensile strength; tensile; iacs	The microstructural evolution and hardness and physical properties of a Cu-Hf alloy at the different processing stages were investigated using hardness, conductivity and tensile measurements, metallographic microscopy, scanning electron microscopy, and transmission electron microscopy. The results reveal that the electrical conductivity of these alloys was above 80% IACS after aging at 450 degrees C, and the hardness and conductivity of the Cu-0.9Hf alloy were 180HV0.5 and 80% IACS, respectively. The softening temperature of the Cu-0.15Hf alloy is 525 degrees C, and the softening temperature of Cu-0.4Hf and Cu-0.9Hf alloys is 550 degrees C. The precipitated Hf-containing phase exhibited a short rod-like structure, the size of which increased with aging time at a slow rate and resulted in the size of similar to 20 nm after aging at 450 degrees C for 300 min.
10.1155-2018-6304518	0	solidification; phase; magnetic; magnetic field; undercooling; field; liquid; separation; peritectic; immiscible; cu-; dendrite; phase separation; microstructure; primary	The solidification microstructure evolution of undercooled Cu-15 wt% Fe alloy melt was studied in this study by the combined method of glass fluxing and overheating. The liquidus and peritectic reaction temperatures of Cu-15 wt% Fe were experimentally obtained, and the obtained results were consistent with the previous studies. Based on the experimental results and related theories, the solidification process and microstructure evolution of undercooled Cu-15 wt% Fe alloy melt were illustrated. The conclusions provide the basis to the further study on the liquid-phase separation and application of copper-iron alloy.
10.1155-2018-8150791	-1		In this work, a Cu/h-BN self-lubricating coating was prepared on cemented carbide by electrospark deposition (ESD). The microstructure and properties of the coating were examined. The results showed that no decomposition of or reactions with h-BN occurred. As the h-BN content and capacitance increased, the number of pores and microcracks in the coatings increased. Additionally, as the capacitance increased, the electrode mass loss increased. However, the specimen mass increased first and then decreased. The coating thickness was affected by the capacitance, deposition time, and volume ratio of h-BN to Cu. The results exhibited were consistent over the tests. The self-lubricating coating exhibited excellent tribological behavior under the test conditions, and the worn surface showed features consistent with shear slippage and abrasive wear.
10.1155-2019-3086716	0	solidification; phase; magnetic; magnetic field; undercooling; field; liquid; separation; peritectic; immiscible; cu-; dendrite; phase separation; microstructure; primary	In this paper, the evolution of solidification microstructure of Cu-40 wt% Pb monotectic alloy of the third element Ni pair under deep undercooling conditions was studied. By comparing the phenomena of liquid phase separation during deep undercooling and rapid solidification of Cu-40 wt% Pb monotectic alloy, the melt of the alloy increases with the undercooling, and the solidification structure appears uneven or even stratified. With the addition of the third element Ni, the liquid phase separation can be effectively inhibited by the change of interfacial energy. The solidified structure undergoes the transformation from coarse dendrite to the first kind of granular and refined dendrite in a wide undercooling range. When the undercooling reaches 143 K, the structure begins to show an inhomogeneous trend.
10.1155-2022-2513391	-1		Copper and its alloys are extensively used in marine applications due to high corrosion resistant behavior. But the corrosion immunity of copper varies with the environmental factors especially the sea water ingredients. Many researchers investigated corrosion level of copper materials in different oceans/seas. Unfortunately, such study is missing in the Bay of Bengal water. Moreover, inclusion of alloying elements can have influence on the corrosion behavior of copper, especially the addition of SnPb-solder for repair works and environmental effects due to ageing. In fact, the urge of using old copper to manufacture new components for marine applications necessitates the characterization of various properties. In this context, present paper is an attempt to investigate the corrosion behavior of copper and solder affected copper to enhance the reuse potential of SnPb-solder affected old/waste copper in contact of the bay water along with comparison with commercial copper alloys. Here, the result shows that overall leaching is increased for the addition of Sn and/or Pb in Cu over the whole immersion period in the stagnant water of the Bay of Bengal. The highest loss is found to be of Cu-Pb alloy which is followed by SnPb-solder affected copper, then Cu-Sn alloy and the lowest loss is of pure copper. The cold-rolled work-hardening has reduced the corrosion rate for all copper alloys. It also reveals that the solder affected copper is more corrosion resistant than commercial copper alloys such as brass and bronze.
10.1155-vib-4220685	-1		To improve the strength of the shaped-charge jet and thereby enhance the penetration power of warheads, the Cu-30Ta alloy with a Cu/Ta mass ratio of 7:3 was prepared based on powder metallurgy technology. The mechanical response characteristics of the Cu-30Ta alloy under dynamic impact were investigated. The strain, strain rate, temperature, and jet strength distributions of Cu-10Ta and Cu-30Ta shaped-charge jets were comprehensively compared, and the plastic deformation mechanisms of the two alloys were analyzed from a microscopic perspective. The results show that the strain-hardening behavior of the Cu-10Ta alloy was more pronounced than that of the Cu-30Ta alloy. The Cu-Ta alloy exhibits good thermal stability. When the ambient temperature rises to 50% of the melting point of the alloy, the stress-softening amount of both alloys was lower than 15% of the initial strength . The average strength of Cu-30Ta alloy jet is 345.91 MPa, which is 42.2% higher than that of Cu-10Ta alloy jet. The Cu phase was the main source of the Cu-Ta plastic deformation ability, and the Ta particles mainly underwent morphological elongation, with limited contribution to the total deformation of the jet. In addition, with increasing Ta content, collision and extrusion of the Ta particles during the jet-formation process intensified, improving the plastic deformation resistance of the material, thereby leading to an improvement in the overall strength of the Cu-Ta alloy.
10.1166-jnn.2004.088	-1		The surface tensions of the Cu-Ag system have been evaluated using Butler's equations. Since the evaluation is dependent on the thermodynamic properties of the surface phases, they are calculated based on the first and second order differentials of the surface tension at infinite dilution. The present study establishes significant differences in the properties between the surface phase and bulk phases of the system. The study of the adsorption behaviour finds silver to be surface active relative to copper, which results in the preferential adsorption of silver in the alloys. Furthermore, in view of the differences in terms of fundamental thermodynamic properties between the two phases coupled with the volume-to-radius ratio as depicted by the Thomson-Freundlich concept, the nano phases of the system exhibit a pronounced increase in the adsorption behaviour relative to that of the planar interface of the. system. As expected based on the above combined effect of the surface properties, present research shows a considerable decrease in the melting points of the metals, solid-solid, solid-liquid transition and eutectic temperature with a consequent increase in the solubilities of the terminal phases of the system.
10.1166-jnn.2011.3357	-1		This study has demonstrated a novel method of fabricating ultrafine-grained oxygen free copper sheets by applying high-ratio differential speed rolling (HRDSR) at room temperature that induces severe plastic deformation. Temperature rise of the sample due to friction and plastic deformation during deformation by HRDSR was significant such that beyond a thickness reduction >65%, the grain refining efficiency was reduced. The proposed processing method holds great potential for continuous production of ultrafine-grained copper alloy sheets.
10.1166-jnn.2014.9470	-1		Accumulative roll-bonding (ARB) process using dissimilar copper alloys was performed up to six cycles (similar to an equivalent strain of 4.8) at ambient temperature without lubricant for fabrication of a new complex copper alloy. The dissimilar copper alloy sheets of oxygen free copper (OFC) and dioxide low-phosphorous copper (DLPC) with thickness of 1 mm were degreased and wire-brushed for the ARB process. The sheets were then stacked together and rolled by 50% reduction so that the thickness became 1 mm again. The sheet was then cut to the two pieces of same length and the same procedure was repeated up to six cycles. A new sound complex copper alloy sheet in which OFC and DLPC are combined each other was successfully fabricated by the ARB process. The tensile strength of the copper alloy increased with increasing the number of ARB cycles, reached 492 MPa after six cycles, which is about three times of the initial material. The average grain size was 12.6 mu m after the 1st cycle, but it became 1.5 mu m after six cycles. Microstructures and mechanical properties of the complex copper alloy fabricated by the ARB were investigated in detail.
10.1166-jnn.2016.11964	-1		The accumulative roll-bonding (ARB) process using different copper alloys of oxygen free copper (OFC) and dioxide low-phosphorous copper (DLPC) was performed up to six cycles at ambient temperature without lubrication. A complex copper alloy sheet in which OFC and DLPC alloys are stacked alternately each other was successfully fabricated by the ARB process. The microstructural evolution and texture development of the complex copper alloy with proceeding of the ARB were investigated by electron back scatter diffraction (EBSD) measurement. The specimen after 1 cycle showed significantly inhomogeneous microstructure in thickness direction, however, the inhomogeneity decreased gradually with increasing the number of ARB cycles. In addition, the grains became finer with the proceeding of the ARB. Resultantly, after 6 cycles, the specimen exhibited an ultrafine grained structure in which the grains above 65% were surrounded by the high angle grain boundaries above 15 degrees. On the other hand, there was no difference in texture development between OFC and DLPC in almost all specimens. In addition, the texture development did not depend on positions in thickness direction; the rolling texture such as {112}< 111 > and {011}< 211 > components developed strongly at all regions.
10.1166-jnn.2017.12581	-1		The bulk porous copper structures with three levels of pore size from macro- to micro- to nano-scale were prepared from Cu-Mn-Al alloy through a facile one-step dealloying process. The excellent performances, such as hierarchical porosity, ultralow density (theoretical density at 0.53 g/cm(3)), and stable mechanical properties, were obtained in these copper structures which could be widely applied in many potential industrial applications. In addition, the process and mechanism of the pore formation was well investigated by SEM and EDX in this paper. The experimental results showed that the hierarchical multi-scale porosities in bulk copper structures were successfully fabricated by the one-step dealloying method. The macro-pores (up to 70 mu m in major axis) and the micro-pores (about 2 similar to 5 mu m in diameter) in this sample were obtained from the removed high-purity Al phase of the precursor alloy, while the nano-pores (about 70 similar to 100 nm in diameter) were generated from the dealloyed intermetallic compounds of Al2Cu and Al11Cu5Mn3, respectively.
10.1166-jnn.2017.14845	-1		Changes of microstructure and hardness of Cu-2 mass% Mg alloy with varying heat treatment conditions were investigated. Oxidation resistant Mg + Mg2Ca master alloy was employed as Mg raw material. Use of Mg + Mg2Ca master alloy caused a significant surface protection from Mg oxidation during melting and casting. As-cast microstructure of Cu-2 mass % Mg-0.15 mass% Ca alloy showed distribution of Cu-Cu2Mg-Cu6Ca eutectic phase. After the solution heat treatment at 973 K for 1 hr, the Cu2Mg phase appeared to be completely decomposed, while distribution of a trace amount of remaining Cu6Ca phase particles was also observed. During aging at 723 K, fine and globular Cu2Mg particles began to precipitate and needle-shaped Cu2Mg also appeared from aging of 10 hrs. After the solution heat treatment, the hardness rapidly decreased and then, the hardness does not change, significantly, in the initial stage of aging. On the other hand, it increased significantly after 5 hrs of aging, and then showed a plateau from 20 hrs.
10.1166-jnn.2018.14285	17	wear; composites; coating; friction; composite; coatings; surface; tribological; properties; wear resistance; resistance; powder; sliding; matrix; wear rate	Sliding bearing maintenance is crucial for reducing the cost and extending the service life. An efficient and practical solution is to coat a restorative agent onto the worn/damaged bearings. Traditional pure-copper (Cu) coating results in a soft surface and poor abrasion resistance. To address this issue, this paper presents a nano-composite repairing coating method. A series of nano-Al/Cu coatings were prepared on the surface of 45 steel by composite electro-brush plating (EBP). Their micro-hardness was examined by a MHV-2000 Vickers hardness tester, and tribological properties by a UMT-2M Micro-friction tester, 3D profiler and SEM. Then, the influence of processing parameters such as nano-particle concentration and coating thickness on the micro-hardness of nano-Al/Cu coating was analyzed. The experimental analysis results demonstrate that, when the nano-Al particle concentration in electrolyte was 10 g/L, the micro-hardness of the composite coating was 1.1 times as much as that of pure-Cu coating. When the Al nano-particle concentration in electrolyte was 20 g/L, the micro-hardness of the composite coating reached its maximum value (i.e., 231.6 HV). Compared with the pure-Cu coating, the hardness and wear resistance of the nanocomposite coating were increased, and the friction coefficient and wear volume were decreased, because of the grain strengthening and dispersion strengthening. The development in this work may provide a feasible and effective nano-composite EBP method for sliding bearing repair.
10.1166-jnn.2018.14979	-1		The effect of Zn on pore characteristics in lotus-type porous Cu alloy was investigated. The lotus-type porous Cu-Zn alloys were fabricated with Zn content from 0.01 to 0.1 at% by the centrifugal casting method. The results demonstrated that the porosity was rarely affected by Zn content. However, the average pore diameter and pore number density of the lotus type porous Cu-Zn alloys were significantly affected by the Zn content. The average pore diameter decreased as the Zn content increased up to 0.01 at%, and then increased as the Zn content increased up to 0.1 at%. In contrast, the variations in the pore number density of the lotus-type porous Cu-Zn alloys showed the reversed tendency with respect to that of the average pore diameter. The increase in heterogeneous nucleation sites for pores attributed to the decreased average pore diameter and the increased pore number density.
10.1166-jnn.2019.17071	-1		Although deformation and aging treatments of Cu-3 wt%Ti alloys dramatically enhance their mechanical properties, the corrosion behavior of ultra-fine grained (UFG) Cu-3 wt%Ti alloys produced by a combination of hot rolling and artificial aging has not been extensively explored yet. To bridge this gap, we herein probe the corrosion behavior of an UFG Cu-3 wt%Ti alloy produced by cold rolling and artificial aging, revealing that cast sample corrosion preferentially occurs around the beta-Cu4Ti phase. Compared to that of the coarse-grained Cu-3 wt%Ti alloy, the corrosion resistance of its UFG counterpart is remarkably higher, which is ascribed to the effects of grain refinement and enveloping between the alpha-Cu matrix and beta-Cu4Ti in the absence of pitting corrosion. The development of ultra-fine microstructure upon the introduction of severe deformation is shown to dramatically improve the corrosion resistance of aging-hardened Cu-3 wt%Ti alloys without sacrificing their mechanical properties. Finally, we demonstrate that solid solution treatment of the Cu-3 wt%Ti alloy results in serious mechanical property deterioration, even though the thus treated samples feature the lowest corrosion current density.
10.1166-mex.2017.1397	2	corrosion; surface; film; electrochemical; films; spectroscopy; layer; current; solution; potential; resistance; composition; x-ray; ions; showed	The corrosion inhibition behavior of an environment-friendly amino acid-methionine (Met) and its synergetic effect with sodium silicate (SS) for copper-nickel alloy (Cu-10Ni) in 3.5% sodium chloride solution were investigated by electrochemical measurement, scanning electron microscope (SEM) and Fourier transform infrared spectrum (FTIR) characterization. The results show that Met, as a cathode corrosion inhibitor, has the highest inhibitive efficiency of 62% at an additive concentration of 40 ppm. When 20 ppm Met and 20 ppm SS are added simultaneously, the inhibitive efficiency is increased to 90% due to a compact and uniform film formed on the surface of the cupronickel specimen under the synergetic effect of two corrosion inhibitors. The existence of characteristic functional groups of these two corrosion inhibitors is confirmed by FTIR results, which indicates that there exists the combination inhibition for corrosion protecting the copper alloy.
10.1166-mex.2022.2126	15	aging; strength; conductivity; electrical conductivity; electrical; mpa; treatment; strengthening; degrees; cu-; cold; precipitation; tensile strength; tensile; iacs	This paper focuses on researching the softening resistance performance of Mg alloy under high temperature and the evolution of microstructure during high-temperature treatment. The results showed that, compared with Cu-0.39Cr-0.12Fe alloy, Cu-0.38Cr-0.04Fe-0.08Mg alloy has higher resistance to softening temperature, hardness and conductivity, which were 40 degrees C, 13 HV, 5% IACS higher than that of Cu-0.39Cr-0.12Fe alloy. Both of the aging precipitated phase of two alloys are nano-Cr phase. Mg can inhibit the growing of nano-Cr phase and the grain recrystallization process significantly. According to 3DAP analysis, the interface structure of Cr/Mg/Cu is formed, which might be the key factor that results in the excellent softening resistance performance of Cu-Cr-Fe-Mg alloy.
10.1166-sam.2012.1361	-1		We present experimental observations of electron-beam irradiation induced diffusion and void formation confined in a one-dimensional two-segment copper-tin (Cu-Sn) nanowire system. The two segmented Cu-Sn nanowires were synthesized by a layer-by-layer electrodeposition method using a nanoporous template. The structure and morphology of the nanowires were characterized by SEM, STEM, TEM, EDS and elemental mapping. Under e-beam irradiation, it is found that the nanowire surface oxide effectively confined the movement of metallic copper and tin atoms and the void regions were formed due to anisotropic diffusion rates and/or Sn melting. It is also seen that Cu/Sn alloy nanoparticles were formed on the oxide layer in the void regions. Such 1-D cylindrical nanowire structure presents an ideal system for understanding dimensionally confined transport phenomena and alloy formation at the nanometer scale.
10.1177-0003702816631295	-1		In this work, the use of multi-pulse excitation has been evaluated as an effective solution to mitigate the preferential ablation of the most volatile elements, namely Sn, Pb, and Zn, observed during laser-induced breakdown spectroscopy (LIBS) analysis of copper-based alloys. The novel remote LIBS prototype used in this experiments featured both single-pulse (SP-LIBS) and multi-pulse excitation (MP-LIBS). The remote instrument is capable of performing chemical analysis of submersed materials up to a depth of 50 m. Laser-induced breakdown spectroscopy analysis was performed at air pressure settings simulating the conditions during a real subsea analysis. A set of five certified bronze standards with variable concentration of Cu, As, Sn, Pb, and Zn were used. In SP-LIBS, signal emission is strongly sensitive to ambient pressure. In this case, fractionation effect was observed. Multi-pulse excitation circumvents the effect of pressure over the quantitative analysis, thus avoiding the fractionation phenomena observed in single pulse LIBS. The use of copper as internal standard minimizes matrix effects and discrepancies due to variation in ablated mass.
10.1177-0021998316664126	16	wear; composite; composites; powders; milling; particles; powder; wt; sliding; friction; hardness; matrix; mechanical; surface; properties	In an attempt to develop new materials that combine structural (mechanical) and functional (electrical and magnetic) properties, a copper composite alloy reinforced through the dispersion of fine Nd2Fe14B intermetallic particles has been synthesized by the powder metallurgy route. Composite master alloy was prepared by blending copper and 8 wt% of intermetallic NdFeB in a planetary ball mill working at 250r/min under argon atmosphere for 10h . Resulting composite powders were encapsulated in Cu cans and then consolidated by extrusion at 1023 K. Microstructure features of blended powders and consolidated materials were characterized by means of X-ray diffraction, scanning electron microscopy, and electron probe micro analysis. Fitting of the X-ray diffraction patterns with the Rietveld method revealed that during processing, some NdFeB particles reacted with copper and oxygen to form Nd2CuO4. The lower Nb content on the Nd2Fe14B intermetallic phase due to this oxidation causes the dispersion of Fe and Fe2B particles, which also have soft magnetic properties but a higher moment compared to Nd2Fe14B. The extruded alloys showed enhanced mechanical properties (with yield strength600 MPa, ultimate tensile strength 700 MPa, and 5% elongation to failure) with satisfactory electrical conductivity (46% IACS) and high values of the coercive field (30,000 A/m).
10.1177-0021998320934860	16	wear; composite; composites; powders; milling; particles; powder; wt; sliding; friction; hardness; matrix; mechanical; surface; properties	In this study, copper powder was reinforced with different weight percentages of Al(2)O(3)particles (0, 5, 10, and 15 wt% Al(2)O(3)coated Ag) to produce Cu-Al(2)O(3)composites by mechanical alloying and uniaxial cold pressing/sintering route. Electro-less deposition was used to coat Al(2)O(3)particles with Ag. The microstructure of the consolidated samples was investigated by X-ray diffraction (XRD), scanning electron microscopy (SEM) and energy dispersive X-ray spectroscopy (EDX) elemental mapping. The porosity, microhardness, and wear behavior of the consolidated samples were also investigated as a function of Al(2)O(3)content. The EDX mapping images reveal that the Al(2)O(3)reinforcement particles were homogeneously distributed into the Cu matrix. Microstructural analysis shows that the addition of Al(2)O(3)coated Ag particles improves density of the composites coating. SEM micrographs result shows that slight porosities exist in the composites produced. Furthermore, the average hardness of the composite coatings varies from 72.3 to 187.6 HV as Al(2)O(3)content increases from 0 to 15 wt%. The wear test results showed that the composite with higher Al(2)O(3)content 15 wt% showed the best wear resistance.
10.1177-0021998320987887	16	wear; composite; composites; powders; milling; particles; powder; wt; sliding; friction; hardness; matrix; mechanical; surface; properties	In the present study, Cu-1, 2 and 3 wt% xGnP composites have been developed by powder metallurgy (PM) route using nanostructured Cu powder and their effect on microstructure, microhardness, sliding wear behaviour has been examined. The crystallite size and lattice strain of Cu after 25 h of mechanical milling have been found to be 16 nm and 0.576%, respectively. Major challenges associated with the development of Cu-xGnP composites is the uniform dispersion of the nanoplatelets in the Cu matrix, which have been dealt out by incorporating the nanostructured Cu- xGnP composites after mechanical alloying leading to the homogenous distribution of nanoplatelets in the Cu-matrix. A significant enhancement in relative density, microhardness and wear resistance of the Cu-3 wt. % xGnP nanofiller composite in particular has been observed due to the uniform distribution of the nanofillers. In Cu-3 wt. % xGnP composite developed using as-milled nanostructured Cu, a microhardness of similar to 1.1 GPa could be achieved which is about similar to 3 times higher than that of the pure sintered Cu sample (similar to 359 MPa). Nanostructured Cu also leads to enhancement of the hardness and wear property as compared to the as-received Cu. The wear mechanism in the various nanostructured Cu-xGnP composites has been studied in details.
10.1177-0309324713511804	-1		This article summarizes the results from uniaxial tension stress-controlled fatigue tests performed at 650 degrees C on Cu-Be specimens. Two geometries are considered: hourglass-shaped specimens and plates weakened by a central hole. The motivation of this present study is that, at the best of the authors knowledge, only a limited number of studies on copper alloys under high-temperature fatigue are available in the literature, and no results from these alloys deal with notched components. In the present contribution, after a brief review of the recent literature, material properties and experimental procedure are described. The new data from un-notched and notched specimens are summarized in the corresponding fatigue curves. By analyzing the fatigue behavior of the plates weakened by central holes, a reduction of the fatigue strength about equal to 40% at 2 million cycles can be noted, whereas the inverse slope, k, is very close to that of un-notched specimens. All fatigue data from un-notched and notched specimens are reanalyzed here in terms of the mean value of the strain energy density. The approach, successfully used to summarize fatigue data from notched specimens tested at room temperature, is extended here for the first time to high-temperature fatigue. In the plates with central holes, the strain energy density is evaluated over a finite size control volume surrounding the highly stressed zone at the hole edge. A value of the radius equal to 0.6mm seems to be appropriate to summarize all fatigue data in a quite narrow scatter band.
10.1177-0734242X241241601	-1		According to the state of the art, most of the mixed copper and copper alloy scrap and residues are processed in a copper smelter. Despite the environmental and economic advantages relative to primary production, the recycling of copper and its alloying elements (zinc, tin, lead, nickel, etc.) requires significantly more energy and cost than remelting unmixed or pure scrap fractions such as separate collected material or production scrap. To date, however, less attention has been given to the mechanical purification of mixed scrap. Therefore, sorting by alloy-specific components (SBASC) using an industrial X-ray fluorescence (XRF) sorting system was tested on the coarse metallic fraction (10-32 mm) of mixed foundry residues. The findings show that XRF-SBASC can recover higher-grade copper concentrates (reaching 98.3% Cu), leaded brass and complex alloys, such as aluminium bronze and red brass with high purities, for the use in the production of new materials. XRF-SBASC can therefore contribute to a more resource efficient metal recycling, mainly by reducing the energy consumption and loss levels in copper metallurgy.
10.1177-09544054211007993	17	wear; composites; coating; friction; composite; coatings; surface; tribological; properties; wear resistance; resistance; powder; sliding; matrix; wear rate	To improve the surface roughness of Copper-Nickel alloy (Cu-Ni alloy) and explore the effect of magnetic abrasive finishing on the surface hardness and hydrophobicity of Cu-Ni alloy, the spherical magnetic abrasives are prepared by atomizing rapid solidification method. The effects of various process parameters on the surface quality of Cu-Ni alloy are explored, and the optimal process parameters of magnetic abrasive finishing of Cu-Ni alloy are obtained. The Neodymium-Iron-Boron permanent magnetic pole is used to grind the workpiece with XK7136C CNC milling machine. Three dimensional profilometer, metallographic microscope, and digital Vickers hardness tester are used to analyze the surface morphology of the workpiece. The hydrophilicity and hydrophobicity of the workpiece are measured by a contact angle goniometer. The effects of spindle speed, feeding rate, processing distance, and abrasive filling amount on the surface quality of workpiece are investigated by the orthogonal experiment and the single factor test. When the spindle speed is 1300 r/min, the feeding rate is 13 mm/min, the processing distance is 1.2 mm, and the abrasive filling amount is 2.0 g, the surface roughness of Cu-Ni alloy decreases from 0.212 to 0.023 mu m and the hardness increases from 114 to 119.8 HV. Finally, the mirror effect of Cu-Ni alloy is achieved. When the optimal test parameters are used, the surface roughness of Cu-Ni alloy can be effectively reduced in a short time. The surface quality of the workpiece is improved, the surface hardness of the workpiece is affected to a certain extent, and the service life of the workpiece is prolonged.
10.1177-09544054251317222	16	wear; composite; composites; powders; milling; particles; powder; wt; sliding; friction; hardness; matrix; mechanical; surface; properties	In this study, composite castings of Cu-based materials were prepared by using electromagnetic energy of frequency 2.45 GHz. Four separate sets of castings were produced inside the domestic microwave applicator cavity with reinforced compositions of up to 15% in steps of 5% for each composite cast (Cu+10%Fe, Cu+10%Fe+5%W, Cu +10%Fe+10%W, and Cu +10%Fe+15%W). A microwave radiation exposure time of 7 min was required to completely melt the pure copper powder. However, the addition of Fe-W reinforcement reduced the exposure time to 5 min (min) for the Cu +10%Fe+15%W composite cast. The formation of different phases was revealed by the X-ray diffraction (XRD) analysis of the cast samples. The composite cast samples exhibited peaks corresponding to Cu64O, Fe3O4, and Cu0.4W0.6. The microstructural analysis demonstrated that the grains grew equiaxed with a uniform dispersion of the reinforcements. The maximum microhardness was achieved 215 +/- 10.07 for Cu+10%Fe+15%W which is 3.39 times better than microwave cast copper sample.
10.1177-0954406218805508	16	wear; composite; composites; powders; milling; particles; powder; wt; sliding; friction; hardness; matrix; mechanical; surface; properties	The functionally graded Cu-11Ni-4Si/10wt%WC composite and its alloy have been synthesized using horizontal centrifugal casting technique to compare the mechanical and tribological improvement and its utility for bearings and bushes. Microstructure analysis and mechanical tests showed 43% improvement in hardness and 160% improvement in tensile strength at inner radial distances compared to the outer composite periphery. Fractural analysis showed ductility for alloy, whereas for composites, brittleness at outer and a combination of both ductility and brittleness were observed at inner. Proportional rise in the wear rate and coefficient of friction was observed with increasing load and sliding distances for both composite and alloy. Composite showed a slight decline in the wear rate and coefficient of friction with an increase in the sliding velocity, while alloy showed a linear rise. Worn surfaces analysis of composite showed the formation of oxide layers, which reduced the coefficient of friction at higher sliding velocity, resulting in lower wear rate.
10.1177-0954406220951597	16	wear; composite; composites; powders; milling; particles; powder; wt; sliding; friction; hardness; matrix; mechanical; surface; properties	Electrical discharge machining (EDM) is broadly used in machining of parts having intricate shapes made of difficult-to-machine materials. During EDM, tool fabrication time through conventional machining processes is generally excessively high . Therefore, alternate tool material and fabrication strategy is sought to reduce machining lead time. In this work, composite tools made of copper, tungsten and boron carbide have been prepared through powder metallurgy (PM) route. The performance of these tools is studied during machining of titanium alloy work piece. The input parameter considered are tool material parameters such as weight percentage of tungsten and boron carbide in the tool and machining parameters like peak current, pulse-on-time and duty cycle. The performance of these tools are evaluated considering the performance measures such as material removal rate (MRR), tool wear rate (TWR), average surface roughness (R-a), surface crack density (SCD), white layer thickness (WLT) and micro-hardness (MH). It is observed that the tool materials have been transferred onto the machined surface forming a hard layer with increased weight percentage of oxygen and carbon during machining. The PM tools exhibit similar performance as solid copper tool with respect to MRR, TWR and surface integrity.
10.1177-09544062231184396	-1		Estimating the forming limit diagram (FLD) is tedious and cost-intensive. Methods driven by data and artificial intelligence are used to determine the relationship between scaled thickness and the forming rates of various cups drawn out of ETP copper sheets. Machine learning (ML) techniques have a good chance of predicting the FLD of copper alloys, and they are being used increasingly in sensitive electronic and structural applications. The current research aims to create ML-based artificial neural network (ANN) tools to model the relationship between scaled thickness and forming rates as a function of formability. The FLD is measured for copper strips of initial dimensions of 1500 mm long, 750 mm wide, and 6 mm thick, whose thickness was reduced successively by 50% in nine incremental steps. Thus, 3, 1.5, 0.75, 0.38, and 0.19 mm sheets were obtained and used to determine FLD through the Nakajima approach . An FEA model of the drawing was made in Altair Inspire Form, and the simulation results were used to train a two-step ML. A Bayesian regularization (BR) and Levenberg-Marquardt algorithm (LM) were used in the first step to predict strains' maximum and minimum points. In the second step, the minor strains predicted in the first step are used as inputs. Using the same feature set, the BR and LM algorithms predict the major strain, showing a linear trend until the middle and then a nonlinear trend. The trained ML model was used to predict unknown intermediate values for estimating the over-learning and over-fitting problems here for 2 and 0.25 mm thick sheets and are validated experimentally. The variation between the FLDs of predicted and experimentally verified data falls between 2% and 5%. Such small changes in the FLD values show that the proposed ML model could be used to predict the FLDs of copper strips.
10.1177-09544089211024420	-1		Due to the widespread use of copper wires in electrical power transmission, the need for raw materials with a homogeneous structure and high strength while maintaining their conductive properties is of high importance. The present study investigates the production of copper wire with improved mechanical properties and homogeneous microstructure due to its nanometre-sized structure. Therefore, the commercial pure copper specimens were subjected to severe plastic deformation (SPD) by means of equal channel angular pressing (ECAP) during four steps at ambient temperature. Due to the creation of a structure with elongated grains in the ECAP process, the deformed specimens were subjected to the direct extrusion operations; thus, a more homogeneous structure was created in them due to the appearance of a secondary radial strain. The obtained results indicate that by applying the simultaneous effects of SPD and direct extrusion on the microstructure, the mechanical properties such as strength and hardness have improved significantly, while the electrical conductivity of pure copper decreased slightly. The outcome can be used as an alternative to current methods for producing high-strength copper wires with suitable electrical conductivity properties.
10.1177-09544089221101368	-1		The difficulties in machinability due to the developments in the technical properties of engineering materials increase the importance of machinability indicators such as surface quality, power or energy consumption and tool life in terms of sustainable machining. In this context, the machinability of a copper-beryllium alloy (C17500), which is used in a wide range of industries and also characterized as a hybrid material, was investigated in vortex tube cooling and dry cutting environments. First, turning experiments were performed with a coated carbide tool and varying cutting speed, feed rate and depth of cut. In the experiments, the total energy consumed during turning and the roughness of the machined surfaces were measured, and analysed experimentally and statistically. In the second stage, mathematical models were developed for the total energy consumption and average surface roughness for both cutting environments with the response surface method. As a result, the chip formation process in the turning of the Cu alloy under vortex tube cooling negatively affected the cutting power and positively contributed to the surface quality. Due to the fact that vortex tube cooling creates a cooling effect rather than lubrication, built-up layer/built-up edge (BUL/BUE) formation on the tool cutting edges caused the change in the tool geometry and thus the chip removal process became more difficult and increased the energy consumption. On the other hand, in the vortex tube cooling application, the surface roughness decreased by an average of 31.4% compared to dry cutting. Furthermore, the predictive mathematical models developed for the total energy consumption and the mean surface roughness can be used with high reliability.
10.1177-1350650120974132	16	wear; composite; composites; powders; milling; particles; powder; wt; sliding; friction; hardness; matrix; mechanical; surface; properties	Brakes are very important component in any vehicle, used to stop the motion of it either by applying mechanical or hydraulic pressure on brake pads. By engaging and disengaging of braking action, the surface of brake components (or) materials is ruined after some time. Therefore, it is important to study and develop a new composition of brake materials which provides optimum coefficient of friction along with increasing wear resistance to the materials. Hence, new combination has been formulated for fabrication of brake composite material using powder metallurgy method which consist of copper-tin alloy mixed with silicon carbide as a base materials, aluminium oxide as an abrasive material with varying volume percentage of graphite and talc powder as a friction modifiers. The pin-on-disc test was performed on brake composite material to analyse their tribological properties namely friction and wear. From tribo-test, it was observed that all composites give the friction coefficient in the range of similar to 0.33-0.51 and the loss of materials in the range of similar to 79-131 mg. Further, the mechanical, thermal stability and surface characterization were also carried out on brake composites using universal testing machine, vicker's hardness tester, thermogravimetric analyser and scanning electron microscope respectively. These results reveal a very marginal change in hardness, increase in compressive strength by increase of talc concentration to the matrix, uniform distribution of reinforcement into the matrix and multi stage degradation of material loss in thermograph .
10.1177-13506501211064413	16	wear; composite; composites; powders; milling; particles; powder; wt; sliding; friction; hardness; matrix; mechanical; surface; properties	This paper explores the addition of h-BN and iron to Cu-based brake pads on the performance benefits. It also investigates the effect of graded layering by synthesizing three and four-layer brake pads by powder compaction and sintering route. The top one or two layers are made of Cu-based composite containing Fe, h-BN, and W, while the middle layer is pure Cu and, bottom steel plate. Two different compositions were explored for the composites by varying Fe content. From the two composite compositions, brake pads with single-layer composite or two-layer composite were synthesized. Characterization of brake pad specimens was carried out using density measurements, optical microscopy, scanning electron microscopy, energy dispersive spectroscopy. The brake pads were subjected to simulated braking tests at braking energy/cycle of 60, 96, and 136 K Joules. Wear rate, coefficient of friction, stopping distance, stopping time, and hardness were measured and compared among other brake pads. The brake pad containing single-layer Fe rich Cu composite showed the best performance in the simulated braking tests. EDS analysis of wear debris shows the formation of iron (boride, nitride, oxide) complex which is indicative of a surface with superior dry lubricating properties. This surface is a result of synergetic interaction between h-BN and Fe particles. The iron particles which are scattered in the Cu matrix composite act as low friction regions on the brake pad surface that interrupt the high friction regions on the Cu matrix, thus reducing the local and bulk temperature rise. The two-layer composite brake-pad showed performance intermediate to the two single-layer brake pads. No advantage due to higher thermal conductivities in Fe deficient composite was observed as the two composite layers, showed similar Fe contents in their matrix phases.
10.1177-13506501221109042	16	wear; composite; composites; powders; milling; particles; powder; wt; sliding; friction; hardness; matrix; mechanical; surface; properties	Bearing materials are used in many industrial applications such as automotive, marine, aviation and hydroelectric power plants. Powder metallurgy is preferred because it is economically more advantageous in the production of this type of material. The main requirement in bearing materials is high tribological properties at a low cost. Therefore, the lower coefficient of friction and wear rate in the bearing materials are among the desired properties. In this regard, the tribological properties and other mechanical, physical, and microstructural properties of the produced samples were investigated in this study. Copper and graphite powder with 5 wt% Mo, Ni, Al, Cr, and W was added to the base alloy of iron. After the production, density measurements, microstructural characterizations, hardness measurements, and dry friction wear tests were carried out on the samples. Analyzing the results, it was found that the highest density value was achieved in the base alloy. Furthermore, a density of over 90% was achieved in all samples. On the other hand, predominantly ferrite and pearlite phases were observed in the microstructure. When the hardness results were examined, it was determined that the Cr added alloys had maximum hardness. In the evaluation of tribological properties, it was shown that Ni alloy had the lowest friction coefficient and Al alloy had the highest friction coefficient. Considering the wear rates, it was seen that the alloy with the lowest wear rate was Cr and the highest wear rate was the alloy with Al additives.
10.1177-14644207211040929	5	materials; thermal; heat; properties; material; welding; sintering; fusion; strength; laser; heat sink; thermal conductivity; mechanical; sink; manufacturing	On-demand additive manufacturing (three-dimensional printing) offers great potential for the development of functional materials for the next generation of energy-efficient devices. In particular, novel materials suitable for efficient dissipation of localised heat fluxes and non-uniform thermal loads with superior mechanical performance are critical for the accelerated development of future automotive, aerospace and renewable energy technologies. In this regard, this study reports the laser powder bed fusion processing of high purity (>99%) copper (Cu), silver (Ag) and novel copper-silver (CuAg) alloys ready for on-demand additive manufacturing. The processed materials were experimentally analysed for their relative density, mechanical and thermal performance using X-ray computed tomography, destructive tensile testing and laser flash apparatus, respectively. It was found that while Ag featured higher failure strains, Cu in comparison showed a 109%, 17% and 59% improvement in yield strength (sigma(y)), Young's modulus (E) and ultimate tensile strength, respectively. As such the sigma(y), E and ultimate tensile strength for laser powder bed fusion Cu is comparable to commercially available laser powder bed fusion Cu materials. CuAg alloys, however, significantly outperformed Ag, Cu and all commercial Cu materials when it came to mechanical performance offering significantly superior performance. The sigma(y) , E and ultimate tensile strength for the novel CuAg composition were 105%, 33% and 94% higher in comparison to Cu. Although slightly different, the trend continued with a 106% and 91% rise for sigma(y) and ultimate tensile strength, respectively, for CuAg in comparison to industry-standard Cu. Unfortunately, E values for industry-standard Cu alloys were not available. When it came to thermal performance, laser powder bed fusion Ag was found to offer a 70% higher thermal diffusivity in comparison to Cu despite the variation in density and porosity. CuAg alloys however only showed a 0.8% variation in thermal performance despite a 10-30% increase in Ag. Overall, the study presents a new understanding regarding the three-dimensional printing and performance of Cu, Ag and CuAg alloys.
10.1177-14644207221131878	-1		In order to explore the reuse potential of waste/scraped copper, an effective characterization of its functional properties under various operating conditions is of great practical importance. The present paper is an attempt to reconnoiter the solder-affected waste copper for high-value engineering applications through the characterization of major mechanical properties. More specifically, the tensile properties of traditional lead-solder-affected copper are investigated and analyzed under the influence of work-hardening and post-thermal treatments. The influential effects of individual elements of the solder on the tensile properties of copper are discussed in a comparative fashion, in which two additional alloy samples, namely, high-copper/tin alloy and high-copper/lead alloy are taken into consideration together with those of copper-tin-lead-alloy as well as pure copper samples. The results of the investigation show that the inclusion of trace-amount of tin and lead in copper affects the corresponding tensile behaviour quite significantly. The strength rising trends due to cold working are observed to be more prominent for the inclusion of lead compared to that of tin. The post-thermal treatments of the work-hardened alloy samples have lowered ultimate strength, yield strength and elastic modulus, but increased the fracture elongation at elevated temperatures. Strain rate variations are also found to be highly influential on all the tensile properties of the solder-affected alloys. Micrographs of the alloy samples have verified the changes in grain shape and grain size responsible for the variation of tensile properties.
10.1177-14644207241301343	-1		An emerging advancement in the field of metallic materials casting is the in-situ microwave casting of metallic materials. To achieve this, the microwave heating process is applied within the applicator cavity, working on the principles of hybrid microwave heating (MHH). This process involves melting the charge, pouring it into an in-situ container, and subsequently solidifying the melted charge. The electromagnetic and thermal properties of the charge influence the interactions between the microwave energy and the material, as well as the melting behavior induced by the microwaves. As for the solidification process, this is also controlled by a cooling condition within the applicator. The present study aims to outline an in-situ casting process for copper-based composite castings fabricated within a multimode cavity, utilizing 900 W at 2.45 GHz. The quality of the developed in-situ cast was assessed by analyzing its characteristics. A microstructural examination revealed that the composite castings exhibited a homogeneous and dense structure. Scanning electron microscopy (SEM) and Energy-dispersive spectroscopy (EDS) analysis was conducted across the casting. The XRD pattern confirmed the presence of major peaks of copper in the composite castings, along with the presence of oxide phases such as Cu64O. Also, the micro indentation hardness of the Cu + 1.5%MWCNT casts was found to be 1.23 times higher than that of microwave-processed pure copper.
10.1179-000705902225004329	2	corrosion; surface; film; electrochemical; films; spectroscopy; layer; current; solution; potential; resistance; composition; x-ray; ions; showed	A low nickel copper alloy commonly used in the plumbing/drainage pipelines on ships was investigated under slow strain rate conditions in air, and in solution containing 3.5%NaCl + 10%MgCl2, with and without 1% ammonia. The tests were conducted at ambient temperature (28+/-1degreesC) at strain rates corresponding to a crosshead speed of 5.76x10(-5) cm min(-1), without a passivation current. The results obtained did not show any significant deterioration in the mechanical properties of the alloy in the tests conducted in air or in solution without ammonia. However, with the introduction of 1% ammonia, a reduction in the material strength and a change in the mode of failure were observed. This paper discusses the results obtained in the present investigation and in particular the load bearing capacity of the material and the modes of failure in Cu-Ni alloys exposed to sea water.
10.1179-003258905X37657	5	materials; thermal; heat; properties; material; welding; sintering; fusion; strength; laser; heat sink; thermal conductivity; mechanical; sink; manufacturing	The application of microwave technology to a diverse range of materials and processes has resulted in a wide spectrum of materials that are commercially processed using microwaves, from the heating of food to the vulcanisation of rubber to the sintering of specialty ceramics. Microwave sintering of elemental or alloy metal powders has gained significance in recent times as a novel processing method since it offers many advantages over the conventional sintering method. Despite substantial R&D investment in this area in the past two decades, no competitive microwave technology has yet emerged for powder metallurgy (PM) sintering. In sharp contrast, because it is 'obvious' that microwaves are reflected by metals, it is not uncommon to be unable to locate many journal papers or literature, wherein metal powders have been sintered in a microwave field. This paper reports the improved mechanical properties and microstructural development of microwave sintered copper and nickel steel PM parts as compared with that obtained using conventional sintering technique. The paper describes the fabrication details of the FC-0208 and FN-0208 composition steel PM parts, and the in house modified commercial microwave oven used for sintering. Microwave sintering resulted in higher sintered density and improved mechanical properties for both Cu and Ni steel PM parts as compared with that processed using conventional sintering under identical conditions. The improved mechanical properties can be attributed primarily to more uniform distribution of the alloying elements, which resulted in greater material homogeneity at the nano- and microlevels as revealed by the Cu and Fe X-ray maps using high spatial resolution scanning transmission electron microscopy (STEM). The optical micrographs of both the etched and unetched samples clearly showed development of novel sintered microstructures having distinct characteristics for the porosity distributions: smooth and rounded pores with low stress concentration regions for microwave sintering as against sharp, triangular and wedge shaped pores with high stress concentration regions for conventional sintering.
10.1179-0032589914Z.000000000208	-1		The formation of a liquid phase during sintering of prealloyed Cu-28Zn powder is potentially attractive for densification, but the effect of gravity results in graded densification which tends to result in heterogeneous cross-sections. The formation of a necklace structure along grain boundaries due to the accumulation of liquid phase with high Zn content, especially at higher temperatures, is also of interest. Evaporation of zinc is another essential feature to consider, since loss of Zn during sintering can influence strongly the mechanical properties of brass products. A macroscopic visualisation of Zn evaporation has been achieved using a copper substrate placed within the gas stream near the sample. FEGSEM observation and XRD analysis of the deposited white mass revealed the formation of nanocrystalline ZnO as a consequence of Zn evaporation. It is proposed that this method could usefully show the evaporation of other alloying elements during sintering of similar alloys.
10.1179-026708300101508360	4	transformation; martensite; martensitic; phase; shape; beta; memory; shape memory; temperature; temperatures; martensitic transformation; gamma; transformation temperatures; effect; thermal	In order to explain the stabilised shape memory behaviour observed during the thermal and mechanical cycling of a Cu-14.86Zn-5.81Al-0.5Fe (wt-%) alloy, X-ray diffraction and optical microscopy studies have been performed. The former have shown that the previously reported reorientation of the alpha brass phase crystallites from alpha(111) to alpha(200), observed during the heating up to 500 degrees C, also occurs during a complete heating-cooling cycle up to 325 degrees C, Optical microscopy studies confirm the increasing tendency for alpha phase preferred formation when the temperature is increased from 325 to 500 degrees C, This texturing effect that occurs during thermal cycling is accompanied by an increase in the amount of alpha phase with a reduction in the amount of beta(2) austenite, Finally, a tensile completely recoverable pseudoelastic strain of almost 0.6%, determined during a loading-unloading cycle applied to a heat treated specimen that contained no austenite, has been ascribed to the reversible formation of a specific martensite variant. MST/4394.
10.1179-026708301225000716	-1		The stress induced martensitic transformation and the relationship between it and the nucleation and propagation of cracks in the Cu-Ni-Al shape memory alloy were investigated through in situ tensile tests by SEM and TEM. The results indicated that the stress concentration ahead of the crack tip could induce formation of stacking faults and different types of martensites. Transmission electron microscope observations showed that the martensites could transform from one type to another type and even reversely to parent during loading. The microcracks nucleated along the martensite/parent interface and intersections between two martensites. When the crack propagated a certain distance, the stress concentration ahead of the crack tip was large enough to result in formation of slip bands, in this condition the microcrack nucleated along slip bands more easily. MST/5011.
10.1179-026708302225007574	4	transformation; martensite; martensitic; phase; shape; beta; memory; shape memory; temperature; temperatures; martensitic transformation; gamma; transformation temperatures; effect; thermal	Motten Cu-Al-Ni alloys have been investigated using the X-ray diffraction method. A distinct pre-peak has been found around a scattering vector magnitude of 18.5 nm(-1) in the structure factor. The pre-peak increases in its intensity with decreasing temperature and the addition of Ni. The appearance of a pre-peak is a mark of medium range order. The structural unit size corresponding to the pre-peak is equal in magnitude to the (I 11) interplanar lattice spacing of the beta phase. The appearance of a pre-peak is due to the existence of a cluster with a beta phase-like structure in the melt. The size of the clusters increases with decreasing temperature but their structural unit size remains constant. Shape memory alloy ribbons can be fabricated by the rapid solidification technique. At a quenching temperature corresponding to that of the lower pre-peak, the structure of the martensite obtained has a lower degree of order and the temperature of the reverse martensitic transformation is lower. At a quenching temperature corresponding to a higher pre-peak, the structure of the martensite obtained has a higher degree of order and temperature of the reverse martensitic transformation is higher. These clusters can become crystal seeds of the beta phase and beta phase develops from these clusters, thus resulting in a correlation between the pre-peak and martensitic transformation.
10.1179-026708304X6059	-1		The strength and toughness of four high silicon content Al-Si-Mg-Cu alloys have been studied at room temperature (RT), 200degreesC and 300degreesC. The fatigue behaviour has also been investigated. The alloys were produced using two very different processing routes: lost foam and squeeze casting. In the tensile tests, the ductility was low for alloys produced via both routes irrespective of the testing temperature. The strength was similar at RT and 200degreesC, but at 300degreesC it fell abruptly. The toughness followed the same trend with testing temperature. Direct observation of fatigue cracks revealed that the brittle silicon and intermetallic particles broke ahead of the crack tip; the fatigue crack advanced by linking the main crack with cracks formed ahead of it. The T6 thermal treatment improved fatigue resistance in the squeeze cast material, especially at high DeltaK values.
10.1179-1432891715Z.0000000001565	-1		Two experimental techniques of uniaxial tensile test and nanoindentation creep were used at room temperature to investigate the deformation mechanism of an electric brush-plated 59-nm bulk Cu. Tensile tests have shown that the strengths decrease from 1000 to 635 MPa and the elongations increase from 9.9 to 15.8% at strain rates from 1 to 10(-4) s(-1). Nanoindentation creep tests have been performed under a maximum constant load with holding time 500 s at a depth of 2000 nm after loading at strain rates ranging from 4 x 10(-1) to 1 x 10(-3) s(-1). The results have exhibited that much wider load plateau can be obtained at higher strain rate. After analysing the deformed and fracture morphologies of tensile samples and creep process in the nanoindentation, it can be concluded that dislocation motion is the dominating mode in the deformation at high strain rate, while grain boundary (GB) sliding plays an important role at low strain rate. This is the main cause why the deformed and fracture surface exhibited different morphologies and the nanoindentation creep displacement showed significant disparity.
10.1179-143307511X12858957675237	-1		The deformation processed Cu based in situ composite has high physical and mechanical performance. In this paper, Cu-10Fe-2Ag-0.15Zr in situ composite was designed and prepared by cold drawing and cold rolling processes. Fe was the main additional element in order to lower the cost. The microstructure evolution was explored by SEM during the plastic deformation. It was shown that Fe fibres were produced during rolling process and the tensile strength of Cu-Fe in situ composite was increased. The effect of distance between Fe fibres on tensile strength was also analysed. Certainly, the intermediate annealing was achieved in the intermittence of rolling to improve the composite's plasticity. Good performance matching of the tensile strength and the electrical conductivity was 713 MPa/61.3% IACS.
10.1179-174328405X16225	-1		Butt welds of 1.6 mm thickness sheet of the Al-Mg-Si-Cu alloy 6013 were produced using a 3 kW Nd : YAG ( neodymium : yttrium-aluminium-garnet) laser. The sheet was welded in the T4 and T6 temper conditions using filler powders of alloys Al-5%Mg, Al-12%Si, Al-20%Si and Al-40%Si. Microstructure, hardness profile, tensile properties and corrosion behaviour of the welds were investigated in the as welded conditions and after a post-weld heat treatment to the T6 temper. Pores were observed in the fusion zone, which exhibited a dendritic microstructure. Post-weld artificial aging increased the hardness in the fusion zone owing to precipitation of strengthening phases. Joint efficiencies between 80 and 90% were achieved for 6013 alloy welds in the as welded T4 condition. After a post-weld heat treatment to the T6 temper, the strength approached 90% of the ultimate tensile strength of the base material 6013-T6 for welds made with silicon rich filler powders. Joints in the as welded T4 and post-weld heat treated T6 temper conditions suffered pitting when exposed to an intermittent acidified salt spray fog. In the as welded T6 condition, welds exhibited zones adjacent to the fusion boundaries that were not corroded. These corrosion free zones were not observed after alternate immersion tests in 3.5%NaCl solution. As welded 6013-T4 joints were susceptible to stress corrosion cracking in the heat affected zone when immersed in an aqueous chloride-bicarbonate solution.
10.1179-174328406X84058	-1		A Cu-10C nanocomposite has been synthesised by high energy milling of elemental powders, followed by annealing at 873 K. Phase identification and microstructure characterisation have been carried out with transmission electron microscopy. Copper grain size ranged from 10 to 120 nm for the as milled material and from 10 to 150 nm after annealing. No graphite reflections could be detected by electron diffraction in either the as milled or annealed samples. Nevertheless, both conditions contain clusters of carbon of <10 nm, which could be of benefit for sliding wear applications. The lattice parameter measured after milling is compatible with a carbon solubility in the copper matrix similar to 0.1 at.-%. The synthesised material showed excellent structural stability at 873 K, which is proposed to be dependent on solute drag effects resulting from boundary segregation. In fact, no grain boundary pinning by nanoparticles has been detected while a decrease in lattice parameter occurred during annealing.
10.1179-174328407X239055	16	wear; composite; composites; powders; milling; particles; powder; wt; sliding; friction; hardness; matrix; mechanical; surface; properties	The present study compares the plain fatigue (PF) and fretting fatigue (FF) behaviour of two coating materials Cu-Ni-In and alumina that were deposited by detonation gun spray process on Al-Mg-Si alloy (AA 6063) samples. Multipass coating was formulated on all four sides of the gauge portions of the fatigue specimens to a thickness of about 150 to 160 mu m and subsequently grinding operation was carried out to reduce the thickness to about 100 mu m. Coatings were characterised in terms of microstructure, microhardness, residual stresses and surface roughness. Uniaxial PF and FF experiments were conducted on uncoated and coated specimens. Cu-Ni-In coating exhibited relatively lower hardness compared with alumina coating but higher than that of the substrate. Ground Cu-Ni-In coating exhibited very high surface compressive residual stress compared with ground alumina coating and substrate. The coated samples experienced higher friction force compared with uncoated specimens. Cu-Ni-In coated specimens exhibited slightly higher friction force compared with alumina coated samples. Cu-Ni-In coated samples exhibited superior PF and FF lives compared with uncoated and alumina coated specimens. This has been explained in terms of differences in the values of surface hardness, surface roughness, residual stress, porosity, adhesion and friction force. As there were many factors, which influenced PF and FF lives, it was not possible to find out the relative importance of each factor. However, it is speculated that the presence of very high compressive residual stress at the surface was mainly responsible for the superior performance of Cu-Ni-In coated specimens.
10.1179-174328413X13789824293182	16	wear; composite; composites; powders; milling; particles; powder; wt; sliding; friction; hardness; matrix; mechanical; surface; properties	The preparation of nanocrystalline Cu by mechanochemical reaction of carbon with copper oxides, CuO and Cu2O, has been studied. The phase and structural transformations, crystallite size, lattice micro strain and lattice parameters were characterised using X-ray diffraction (XRD). Morphology of the synthesis products was evaluated by scanning electron microscopy (SEM). It was found that the reduction process of CuO to Cu takes place in two steps, while Cu was produced directly through one step from Cu2O. In addition, kinetics of nucleation and formation of Cu through solid state reduction of CuO is different from the reduction of Cu2O. The results reveal that the average crystallite size of copper derived from CuO after 100 h milling is similar to 18 nm, while for copper derived from Cu2O after 30 h is similar to 27 nm. A trivial solid solubility of C in Cu was achieved by mechanical alloying.
10.1179-1743284711Y.0000000099	4	transformation; martensite; martensitic; phase; shape; beta; memory; shape memory; temperature; temperatures; martensitic transformation; gamma; transformation temperatures; effect; thermal	The reproducibility of thermally induced reversible martensitic transformation, occurring in a Cu-15Zn-6Al (mass-%) shape memory alloy during heating, was studied on three different fragments of martensitic alloy subjected to complex thermal cycling comprising four series of five heating-cooling cycles, applied on a differential scanning calorimetry (DSC) device, between room temperature (RT) and three maximum temperatures: 453, 463 and 473 K respectively. After each series of heating-cooling cycles the fragments were naturally aged at RT for 37 days (similar to 3.2 Ms). Thermograms of DSC revealed a gradual diminution in the magnitude of martensite reversion to parent phase, accompanied by decreasing tendencies of both critical temperatures and transformation rates, which reflect a gradual loss of thermal memory, associated with 'amnesia' occurrence. Scanning electron microscopy observations coupled with energy dispersive X-ray spectroscopy performed at the end of complex thermal cycling revealed that 'amnesia' occurrence was associated with changes in the morphology of martensite plates, from parallel plate-like to interblocking needle-like, and with an increase of chemical fluctuations, as an effect of the intensification of atomic migration.
10.1179-1743284712Y.0000000013	-1		The present work is concerned with the ability of the incremental melting and solidification process to be used in a controlled way to produce functionally graded materials in industrial environments. For this purpose, the influence of the main process parameters, namely relative mould/coil rate and melt temperature, is evaluated in relation to the obtained final component chemical composition gradient. Several graded components of Cu-Sn alloys were produced. The effect of the process parameters on the final component gradient was quantified. It was verified that both the melt temperature and the relative mould/coil rate play a similar role in final component chemical composition gradient. Predictive equations for the gradient, namely the extension of chemical composition gradient zones, are proposed based on the two studied variables.
10.1179-1743284712Y.0000000082	-1		In the present work, the process of equal channel angular pressing of dispersion strengthened Cu-1.1 wt-%Al2O3 containing nanometric alumina particles was investigated by means of mathematical modelling and experimental testing. Through the modelling, deformation parameters such as hydrostatic pressure distribution and strain field were determined, and the effect of deformation path on these parameters was estimated. Equal channel angular pressing as well as mechanical and microstructural evaluations were also conducted to assess mechanical properties, grain structure and void volume fraction after deformation in different routes. The results indicate that distributions of plastic strain and hydrostatic stresses are significantly affected by deformation path route as well as utilised die design. Furthermore, void formation around hard alumina particles may occur in regions with high tensile hydrostatic stresses leading to fracturing during deformation.
10.1179-1743284713Y.0000000394	11	glass; bulk; metallic; bulk metallic; gfa; bmg; glassy; metallic glass; ability; bulk metallic glass; amorphous; addition; crystallization; mm; glass-forming	In the present paper, activation energy, viscosity and fragility of two In alloyed Cu-Zr-Ti-In bulk metallic glasses are evaluated by differential scanning calorimetry and thermomechanical analysis respectively. E-g of 60Cu-34Zr-5Ti-1In and 58Cu-34Zr-5Ti-3In is 175 +/- 9 and 182 +/- 5 kJ mol(-1) respectively. Ex of 60Cu-34Zr-5Ti-1In and 58Cu-34Zr-5Ti-3In is 369 +/- 24 and 317 +/- 10 kJ mol(-1) respectively, indicating that increasing the content of indium decreases the value of E-x of the as cast bulk metallic glasses. By means of comparison of activation energies referring to the crystallisation peak temperature, one can find that the second step crystallisation of both bulk metallic glasses is easier to occur. The possible phases of the annealed samples are determined. Thermomechanical analysis shows that viscosity for 58Cu-34Zr-5Ti-3In is larger than that for 60Cu-34Zr-5Ti-1In in the supercooled region, but Vogel-Fulcher-Tammann (VFT) temperature of 58Cu-34Zr-5Ti-3In is lower than that of 60Cu-34Zr-5Ti-1In. Both 60Cu-34Zr-5Ti-1In and 58Cu-34Zr-5Ti-3In bulk metallic glasses are stronger than o-terphenyl, but more fragile than SiO2. 58Cu-34Zr-5Ti-3In is stronger than 60Cu-34Zr-5Ti-1In. It indicates that increasing indium content can decrease the VFT temperature but make glass stronger.
10.1179-1743284713Y.0000000405	-1		The effect of squeezing pressure on the heat treatment response and electrical conductivity of the cast alloy is not clear yet. The present research aims at investigating and elucidating them. It was found that the hardness peak occurred earlier for the pressurised cast alloy during the aging process as compared with non-pressurised one. Squeezing pressure reduces the time required for heat treatment. This significant fact was ignored by most researchers. Pressure also improved the electrical conductivity of the cast alloy. The results showed that the electrical conductivity of samples increases with increasing the aging time and temperature. Moreover, better mechanical properties including high hardness and ultimate tensile strength and good toughness and ductility of the pressurised cast samples indicate that these samples are more reliable to be used for different applications.
10.1179-174329005X76637	-1		Nanocrystalline Cu Co (Cu-25Co by atomic fraction) powder for giant magnetoresistance (GMR) application has been synthesised by laser ablation method. The effect of Co precipitating evolution on the GMR properties during annealing has been investigated using energy filtered transmission electron microscopy (EFTEM) and X-ray diffraction. The as synthesised Cu-Co powder was 10 nm in diameter and formed a solid solution with an fcc structure. On the thermal stability during annealing the Cu-Co powder, the grain growth commenced before the phase separation of Cu and Co. As the result of the phase separation, nanocrystalline fcc Co particles with an average diameter of 5 nm were uniformly dispersed in Cu matrix. The relationship between the GMR property and the microstructural evolution of Co precipitate could be understood by the compositional profile showing a sinusoidal shape from EFTEM images.
10.1179-174329006X96030	-1		A novel Cu-Cr-Zr alloy matrix composite reinforced with Al2O3 particles was designed and fabricated by a powder metallurgy plus hot extrusion method, in order to obtain the combined effects of aging strengthening and composite reinforcing. The CuCrZr powder was produced through water atornisation technology and used as the starting materials of the matrix. The solid solubilities of Cr and Zr elements in copper, which increased during the rapid solidification process, helped to improve the strength of the matrix after aging treatment. This was in favour of exerting the load bearing effect of the Al2O3 reinforcements. Fabrication experiments showed that by choosing the 38 pm CuCrZr powder, cold pressed at 380 MPa and hot extruded at 400 degrees C, the relative densities of 7 vol.-%Al2O3 Composite reached 99.4%. The Al2O3 particles significantly accelerated the aging process of the composites. With increasing Al2O3 content, the Vickers hardness and ultimate tensile strength at elevated temperatures were effectively improved. The main tensile fracture mechanisms of the composites were severe plastic deformation of the matrix and the induced rupture and debonding of the Al2O3 particles.
10.1179-1743290111Y.0000000015	-1		Amorphous Cu50Zr40Ti10 powder was fabricated in the particle size range <50 mu m by gas atomisation method. Gas atomised Cu50Zr40Ti10 amorphous powder exhibits the glass transition temperature T-g of 629.5 K and the crystallisation temperature T-x of 693.2 K respectively. The gas atomised Cu50Zr40Ti10 amorphous powder possesses a high supercooled liquid region Delta T-x of 63.7 K suitable for being hot pressed. In addition, the Cu50Zr40Ti10 amorphous powders were consolidated by hot pressing method based on an L-9(3(4)) orthogonal design. The optimum consolidation condition for the Cu50Zr40Ti10 amorphous powder is first precompacted under the pressure of 75 MPa, and then consolidated under the pressure of 450 MPa at the temperature of 380 degrees C respectively. The significance of three factors is examined by the analysis of variance for the density and thermal conductivity respectively. The effect of three factors on the density and thermal conductivity is also discussed.
10.1179-174329305X40615	5	materials; thermal; heat; properties; material; welding; sintering; fusion; strength; laser; heat sink; thermal conductivity; mechanical; sink; manufacturing	Melt run trials were carried out on Cu-Ni bars using a CO2 laser source in order to analyse the effects of welding parameters (i.e. laser power, welding speed) on geometrical characteristics and on the microstructure of the bead. Experimental results were then used to determine the source parameters to be employed in a finite element model (FEM) of the welding process, with particular attention paid to the thermal field induced by the laser beam. A specific procedure, named 'automatic remeshing technique', was used in order to minimise the computation time. The aim was to create a reliable numerical model, suitable for the optimisation, in practical cases, of welding processes of these kinds of materials. A good correlation, in terms of predicted cooling rates, with the values calculated from SDAS measurements, was observed.
10.1179-174329405X40858	2	corrosion; surface; film; electrochemical; films; spectroscopy; layer; current; solution; potential; resistance; composition; x-ray; ions; showed	Investigations into nickel electrodeposits on dc magnetron sputtered copper substrates are reported. Thin layers of copper were deposited by dc magnetron sputtering on mild steel substrates. Onto these sputtered copper surface, layers of nickel were electrodeposited using a Watt's bath . The coatings were vacuum annealed at 200 degrees C for 120 min. The growth of the deposit is discussed in terms of structural and microstructural analysis by X-ray diffraction (XRD), SEM and atomic force microscopy (AFM). The orientation along (111), (200) and (220) was observed for the vacuum annealed CU3.8Ni alloy deposits. Uniform and pinhole free morphology was observed from SEM. AFM images reveal that these coatings have a granular morphology. The corrosion behaviour of these samples in a 3.5 wt-%NaCl solution was examined. A decrease in I-corr, and high charge transfer resistance indicated the improved corrosion resistant behaviour of the nickel sample plated over a sputtered copper base.
10.1179-174329409X409440	16	wear; composite; composites; powders; milling; particles; powder; wt; sliding; friction; hardness; matrix; mechanical; surface; properties	Cu based materials are widely used as journal bearings. These materials have a good tribological performance in journal bearings. Pure copper is not generally used due to its low mechanical and wear properties. It is generally used as alloys. In this study, tribological properties of copper bearings manufactured from pure copper were investigated by boronising at 950 degrees C. The SAE 1050 steel shaft was used as counter abrader. Experiments were carried out at 20 N load and 1500 rev min(-1) speed every 30 min for 2.5 h using radial journal bearing wear test rig. As a result, boronising increased wear resistance.
10.1179-1743294411Y.0000000049	2	corrosion; surface; film; electrochemical; films; spectroscopy; layer; current; solution; potential; resistance; composition; x-ray; ions; showed	In this paper, a new environment friendly electroless plating bath using sodium hypophosphite as reductant and nitrilotriacetic acid as complexing agent was investigated under the acid condition. The effects of bath temperature, pH, CuSO4 center dot 5H(2)O concentration, nitrilotriacetic acid concentration and NaH2PO2 center dot H2O concentration upon the deposition rate and the bath stability were studied. The electrochemical results indicated that the deposition rate of the electroless copper increased with the decrease in the pH, and it reached 2.4 mu m h(-1) when the bath pH was 6.0. The as deposited Cu films were characterised by energy dispersive X-ray analyser, X-ray diffraction, atomic force microscopy and resistivity measurement. The quality of the Cu films were improved by the addition of a surfactant PEG-600, and a uniform copper film with a low resistivity (2.60 mu Omega cm) was obtained, which was able to be used as seed layer for electroplating Cu.
10.1179-174591911X13226697790578	2	corrosion; surface; film; electrochemical; films; spectroscopy; layer; current; solution; potential; resistance; composition; x-ray; ions; showed	A pyrophosphate based solution, as an acidic electrolyte, was developed for bronze electroplating. By using a statistical experimental design, response surface method, the effects of five factors [copper concentration (Cu), tin concentration (Sn), pyrophosphate concentration (P), current density j and pH] on the composition of the electroplated alloy as well as the process efficiency were evaluated. Statistical analysis indicated that all the parameters were significant and a second order polynomial model was successfully fitted to the data for both the alloy composition and the process efficiency. Based on the results obtained, a solution of Cu(II)=8.04 g L-1, Sn(II) =26.36 g L-1, P=113.22 g L-1 at pH=3.14 and j=10 mA cm(-2) was introduced as the best electroplating solution in terms of process efficiency.
10.1179-175355511X13240279340444	6	grain; deformation; strain; strength; dislocation; cu-; tensile; size; ecap; grain size; sfe; ductility; hardening; high; stress	Samples of pure Cu cylinder were plastically deformed by the combination of cold forging (CF) and cold drawing (CD) at liquid nitrogen temperature. X-ray diffraction measurements indicate that an increase in deformation strain leads to a decrease in crystallite size and an increase in twin densities for the CF and CD processed ultrafine grained samples. Dynamic recovery is suggested to start during the deformation process and leads to a decrease in dislocation density at large deformation strains. The increase in twin density could compensate the loss of microhardness because of the decrease in dislocation density. The electrical conductivities of CF+CD samples were tested through standard four-probe method, all of which are higher than 92% the International Annealed Copper Standard. The results suggest that the strength of pure Cu could be improved and still keep its relatively high electrical conductivity by introducing deformation twins into its microstructure.
10.1186-s10033-024-01170-x	-1		Triply periodic minimal surfaces (TPMS) are structures with smooth surfaces and excellent energy absorption properties. Combining new functional materials, such as shape memory alloys, with TPMS structures provides a novel and promising research field. In this study, three TPMS structures (Gyroid, Diamond, and Primitive) of Cu-11.85Al-3.2Mn-0.1Ti alloy were printed by laser powder bed fusion, which is favorable for the fabrication of complex structures. The manufacturing fidelity, mechanical response, and superelastic properties of the three structures were investigated. Stress distributions in the three structures during compression were analyzed by finite element (FE) simulation. The three structures were equipped with high-quality, glossy surfaces and uniform pores. However, due to powder adhesion and forming steps, there were volumetric errors and dimensional deviations between the samples and the CAD models. The errors were within 1.6% for the Gyroid and Diamond structures. The dimensional deviations at the nodes in the three structures were less than 0.09 mm. The microstructures of all structures were beta 1 martensite, consistent with the cubic sample. Experimental results of compression showed that the structures underwent a layer-by-layer compression failure mode, and the Primitive structures exhibited a more pronounced oscillatory process. The Diamond structures showed the highest first fracture stress and strain of 164.67 MPa and 13.89%, respectively. It also possessed the lowest yield strength (61.97 MPa) and the best energy absorption properties (7.6 MJ/m3). Through the deformation analysis, the Gyroid and Diamond structures were found to fracture at a 45 degrees direction, while the Primitive structures fractured horizontally. These findings were consistent with the results obtained from the FE simulation, which showed equivalent stress distributions. After applying various pre-strains, the Diamond structures displayed the highest superelastic strain of up to 3.53%. The superelastic recovery of all samples ranged from 63.5% to 71.5%.
10.1186-s11671-017-2052-6	4	transformation; martensite; martensitic; phase; shape; beta; memory; shape memory; temperature; temperatures; martensitic transformation; gamma; transformation temperatures; effect; thermal	The paper studies the influence of magnetic field on magnetic and mechanical properties of Cu-Mn-Al alloy under annealing. The comparative analysis of the magnetic field orientation impact on solid solution decomposition processes in a fixed annealing procedure is held using the methods of low-field magnetic susceptibility, specific magnetization, and microhardness test. The paper highlights changes in the magnetic and mechanical properties of Cu-Al-Mn alloy as the result of change in a critical size of forming precipitated ferromagnetic phase and determines correlation in the behavior of magnetic and mechanical properties of the alloy, depending on a critical nucleus size of forming precipitated ferromagnetic phase.
10.1186-s11671-017-2378-0	-1		Multi-walled carbon nanotubes (MWCNTs) and graphenes have been taken for novel reinforcements due to their unique structure and performance. However, MWCNTs or graphenes reinforced copper matrix composites could not catch up with ideal value due to reinforcement dispersion in metal matrix, wettability to metal matrix, and composite material interface. Taking advantage of the superior properties of one-dimensional MWCNTs and two-dimensional graphenes, complementary performance and structure are constructed to create a high contact area between MWCNTs and graphenes to the Cu matrix. Mechanical alloying, hot pressing, and hot isostatic pressing techniques are used to fabricate Cu matrix self-lubricating nanocomposites. Effects of MWCNTs and graphenes on mechanical properties and microstructures of Cu/Ti3SiC2/C nanocomposites are studied. The fracture and strengthening mechanisms of Cu/Ti3SiC2/C nanocomposites are explored on the basis of structure and composition of Cu/Ti3SiC2/C nanocomposites with formation and function of interface.
10.1186-s40494-016-0092-3	2	corrosion; surface; film; electrochemical; films; spectroscopy; layer; current; solution; potential; resistance; composition; x-ray; ions; showed	Basic sodium copper carbonate, Na-3[Cu-2(CO3)(3)(OH)]center dot 4H(2)O, has been mentioned as heritage corrosion product of copper alloys in two publications. The identification relied on the comparison of the powder diffractograms with ICDD 28-1048. But this erroneous reference card clearly measured chalconatronite, Na2Cu(CO3)(2)center dot 3H(2)O, instead which is indeed the product formed in the synthesis on which the card is based. Therefore, ICDD 28-1048 should be deleted.
10.1186-s40494-022-00736-z	2	corrosion; surface; film; electrochemical; films; spectroscopy; layer; current; solution; potential; resistance; composition; x-ray; ions; showed	A multidisciplinary approach has been applied to investigate the production technology of a collection of copper-based artefacts found during archaeological excavation campaigns carried out in the Almohad neighbourhood of Martulah, the Islamic name of modern Mertola (South of Portugal). In stark contrast to other Islamic materials found in the same site such as common and finely decorated pottery, glass, and bone artefacts, metal objects have received less attention despite the high number of artefacts recovered. This study focuses on the chemical characterisation of 171 copper-based artefacts dating back to the 12th and the first half of the thirteenth centuries. The artefacts are daily use objects and consist of personal ornaments (earrings, rings, and casket ornaments), tools (spindles, spatulas, and oil lamp sticks) and artefacts with unknown functions. The analytical results by X-ray fluorescence Spectroscopy (XRF) provided information not only about technological issues but infer as well on the socio-economic implications of metal consumption in Islamic Mertola. Results revealed that metals were produced using a variety of Cu-based alloys, namely unalloyed copper, brasses (Cu + Zn), bronzes (Cu + Sn), and red brasses (Cu + Sn + Zn), with a variable concentration of Pb, without any apparent consistency, as a likely result of recurrent recycling and mixing scrap metals practices or use of mineral raw materials available locally.
10.1186-s40494-022-00839-7	2	corrosion; surface; film; electrochemical; films; spectroscopy; layer; current; solution; potential; resistance; composition; x-ray; ions; showed	Archaeological objects based on copper alloys (such as bronze wares) usually suffer from bronze disease that results from the existence of CuCl on the surfaces. The surface-coating Cu-2(OH)(3)Cl can release Cl- and lead to further corrosion during the storage procedure. The central aim of the work is the verity the effectiveness of low-temperature radio-frequency (RF) plasma for the removal of CuCl and Cu-2(OH)(3)Cl from the bronze wares. In this work, CuCl and Cu-2(OH)(3)Cl patina were synthesized on copper by a simple solution method. The chemical and aesthetic features before and after plasma treatment were characterized using optical microscopy (OM), SEM-EDS, XRD, and XPS. The results show that Ar-H-2 plasma could reduce the CuCl to Cu efficiently, which achieves pleasing esthetics as well as removes the chlorine (Cl atomic ratio decrease from 46.0 to 3.6%). For Cu-2(OH)(3)Cl, the air plasma treatment exhibit better performance compared to the Ar-H-2 plasma treatment, judging from the aesthetic effect and the removal effect of chlorine (Cl atomic ratio decrease from 14.8 to 3.3%).
10.1186-s40494-023-00915-6	2	corrosion; surface; film; electrochemical; films; spectroscopy; layer; current; solution; potential; resistance; composition; x-ray; ions; showed	This contribution synthesises the PIXE and ICP-AES elemental analyses carried out on a large dataset, comprising of 300 copper-alloy objects dating mainly to the Late Middle Ages. The objects are drawn from heritage institutions and archaeological contexts in various regions between the Meuse and the Loire rivers (France and Belgium). This investigation focuses on the main elements that make up the alloys (Cu, Zn, Sn, Pb). Past studies have often defined the composition of an alloy as an intentional choice, however in this paper we aim to identify the constraints in alloy manufacture in a bid to understand the degree of freedom enjoyed by craftsmen during this period. We will also evaluate to what degree the constraints imposed by technique, economic conditions and social requirement, affected production in a complex multifactorial system. We have opted to define alloys by object type, functional area and social context, by chronology and product ranges. For cast table- and the kitchenware, we have observed that alloys and the objects are standardised on a trans-regional scale. Conversely, the hammered objects are produced with a greater freedom, leading to a new hypothesis regarding specific workshop practices. Finally, we will propose a predictive model for cast objects that we hope is better suited for the study of heritage objects, their materials and their production processes, to be verified in future studies. This approach emphasises the importance of considering everything that makes an object what it is: its function, status and place in the market, when researching heritage materials.
10.1186-s40494-024-01176-7	2	corrosion; surface; film; electrochemical; films; spectroscopy; layer; current; solution; potential; resistance; composition; x-ray; ions; showed	A group of copper-based objects excavated at Deh Dumen cemetery, in south-western Iran, was studied and analysed to examine the long-term corrosion morphology and mechanism in the soil burial environment. For this purpose, twenty-two samples from twenty-one copper-based vessels were studied and analysed using X-ray diffraction, scanning electron microscopy-energy dispersive X-ray spectroscopy, micro-Raman spectroscopy and metallography techniques. The results of the analyses showed that the majority of vessels are made of tin bronze, along with two arsenical copper samples. The extent of corrosion observed ranges from very thin corrosion crusts to thick crusts and entirely corroded structures. These three identified corrosion morphologies display a multi-layered corrosion stratigraphy as well as the preserved limit of the original surface. The corrosion crusts include internal tin-rich and external copper-rich layers, and the main corrosion mechanism for the formation of multi-layered corrosion crusts is decuprification or selective dissolution of copper during the long-term burial time in a moderately Cl-contaminated soil. The three identified corrosion morphologies are similar to the previously published morphologies, but some clear deviations are apparent and are discussed here.
10.11900-0412.1961.2022.00180	-1		The performance requirements for copper alloys are increasing with the rapid development of transportation, electrical, aerospace, and electronics in modern industry. Cu-Cr-Zr alloy has exceptional strength and electrical conductivity as typical precipitation strengthening copper alloy. Strength and conductivity are mutually exclusive properties. The goal of realizing the high strength and conductivity of copper is a crucial subject in modern copper industry development. In this study, the effects of cryorolling on the microstructure, mechanical properties, and electrical conductivity of Cu-1Cr-0.2Zr-0.25Nb alloy were examined and the effects of numerous aging processes on the type, morphology, and distribution of precipitates were investigated. The findings depict that the Cu-1Cr-0.2Zr-0.25Nb alloy primarily comprised the Cr phase, Zr-rich phase, Cr2Nb phase, and Cu matrix phase. The fcc Cr nanoprecipitates can be precipitated in Cu-1Cr-0.2Zr-0.25Nb alloy after aging at 450 degrees C for 30 min. The bcc Cr nanoprecipitates can be formed after aging at 450 degrees C for 300 min. After cryorolling and aging treatment, the mixed structures, such as nanoprecipitation phase, nanodeformation twins, and dislocations in the Cu-1Cr0.2Zr-0.25Nb alloy are produced and this alloy demonstrates remarkable comprehensive properties. The tensile strength of 700 MPa and electrical conductivity of 73.29%IACS were attained for the cryorolled Cu1Cr-0.2Zr-0.25Nb alloy after aging at 450 degrees C for 30 min; after aging at 450 degrees C for 300 min, the conductivity can reach 79.81%IACS, and the corresponding tensile strength, yield strength, and hardness are 646 MPa, 606 MPa, and 212 HV, respectively. Combining the experimental findings with the computations of contribution to strengthening, it can reasonably be inferred that dislocation and precipitation strengthening were the primary strengthening mechanisms of Cu-1Cr-0.2Zr-0.25Nb alloy.
10.1209-0295-5075-121-38002	0	solidification; phase; magnetic; magnetic field; undercooling; field; liquid; separation; peritectic; immiscible; cu-; dendrite; phase separation; microstructure; primary	The influence of a weak transverse magnetic field on the microstructure in directionally solidified Cu-20 wt% Sn peritectic alloys at low speeds (0.8-1.2 mu m/s) was investigated. Experimental results indicated that the magnetic field caused the evolution of the two-phase microstructure from coupled growth to band. Moreover, it was also found that the magnetic field induced the crystal orientation of the primary phase. The above results may be attributed to the effect of the magnetic field on the mass and heat transfer during directional solidification. Copyright (C) EPLA, 2018
10.12442-j.issn.1002-185X.20240107	10	composites; nanoparticles; strength; matrix; high; strengthening; particles; conductivity; composite; electrical; mpa; sintering; ods; grains; mechanical	Compared with Cu/Al2O3 composites, high-strength Cu/Al2O3 composites usually exhibit obviously deteriorated electrical conductivity. A chemical and mechanical alloying-based strategy was adopted to fabricate ultrafine composite powders with low-content reinforcement and constructed a combined structure of Cu ultrafine powders covered with in-situ Al2O3 nanoparticles. After consolidation at a relatively lower sintering temperature of 550 degrees C, high-volume-fraction ultrafine grains were introduced into the Cu/Al2O3 composite, and many in-situ Al2O3 nanoparticles with an average size of 11.7 +/- 7.5 nm were dispersed homogeneously in the Cu grain. Results show that the composite demonstrates an excellent balance of high tensile strength (654 +/- 1 MPa) and high electrical conductivity (84.5 +/- 0.1% IACS), which is ascribed to the synergistic strengthening effect of ultrafine grains, dislocations, and in-situ Al2O3 nanoparticles. This approach, which utilizes ultrafine composite powder with low-content reinforcement as a precursor and employs low-temperature and high-pressure sintering subsequently, may hold promising potential for large-scale industrial production of high-performance oxide dispersion strengthened alloys.
10.12442-j.issn.1002-185X.20240460	-1		A straightforward, highly effective, and environmentally friendly technique was investigated for protecting carbon steel surfaces from corrosion, i. e., depositing Cu-Ni alloy coatings on the workpiece's surface to impede corrosive medium. The effects of current density and copper ion concentration (Cu2+) on the composition, morphology, and properties of the coating were analyzed using scanning electron microscope, X-ray energy dispersive spectrometer, Vickers hardness tester, friction and wear tester, and electrochemical testing. Results show that a cauliflower-like Ni-rich protrusion structure appears on the coating surface. The lower current density and Cu2+ concentration affect the Vickers hardness and wear resistance of the coating by altering the microstructure and Cu/Ni content, both leading to a decrease in hardness and wear resistance. When the current density is 10 mAcm-2 and the Cu2+ concentration is 0.1 molL-1, the corrosion current density of the deposited sample reaches 1.389x10-5 Acm-2, and its surface corrosion damage is reduced compared to the uncoated sample after 24 h of salt spray test. Research on the deposition mechanism indicates that Cu2+ undergoes instantaneous nucleation under diffusion control, tending to grow vertically and form cauliflower-like protrusions, while Ni2+is discharged uniformly across the surface under electrochemical control.
10.12693-APhysPolA.131.1315	-1		The influence of thermoplastic processes through severe plastic deformations carried out at ambient temperature and through rolling carried out at cryogenic temperature on the recovery for two types of materials was investigated. As experimental materials, there were used oxygen free high conductivity copper and FeSi steel presenting materials with middle and high stacking fault energy, respectively. Both materials have been previously investigated, however mainly considering their material properties. In this study, oxygen free high conductivity Cu was processed by 13 passes through equal channel angular rolling which belongs to the severe plastic deformations group of methods. The rolling of FeSi steel at ambient and cryogenic temperatures was performed using a laboratory duo rolling mill, samples were rolled only by one pass. The aim of this study was to insert the strain to the materials with different stacking fault energy (middle and high) under ambient and cryogenic thermal conditions, respectively, and subsequently to observe the influence of stored energy on structural recovery of materials through differential scanning calorimetry method. This study implies that the recovery process characterized by the mobility of structural defects begins earlier for FeSi steel compared to oxygen free high conductivity Cu.
10.12693-APhysPolA.132.1087	2	corrosion; surface; film; electrochemical; films; spectroscopy; layer; current; solution; potential; resistance; composition; x-ray; ions; showed	Copper zinc alloys were electrodeposited in the form of thin films. Electrodeposition process was carried out in non-cyanide aqueous medium, under constant current. Effect of pre-deposition ultrasonication of solution was investigated. In other words ultrasonic treatment was applied only before the electrodeposition. Solutions were subjected to high-energy ultrasonication for increasing times. Cyclic voltammetry was used to understand changes occurring due to duration of ultrasonication. No ultrasonication was applied during deposition. Atomic composition of resultant films were revealed by MP-AES. It was found that implementation of ultrasonic treatment before electrodeposition affects CV characteristics, when compared to non-ultrasonicated solution. Atomic composition of fabricated samples were found to be close to each other, some of them showing more deviation.
10.12693-APhysPolA.132.1091	-1		Thin film brass alloys were galvanostatically electrodeposited from non-cyanide citrate solutions. Aqueous sulphate solutions were used as deposition medium. It was aimed to understand the effect of ultrasonication of the solutions before electrodeposition process. Ultrasonication was not applied during deposition. This method was utilized to change solution characteristics, by applying high energy via cavitation mechanism, which would result in changes in resultant film properties. X-ray diffraction technique was used to investigate phase formation in samples. Moreover X-ray diffractograms were also used to calculate grain size values. Cu and Zn elements were codeposited successfully to form brass alloys. When phase formations in the samples were compared to each other, it was concluded that although there are small differences between X-ray diffractograms of samples, ultrasonic treatment before electrodeposition is not an effective way to alter phase characteristics of CuZn alloy samples, since all samples have shown similar X-ray diffraction graphs. Grain size is found to get smaller with presence of ultrasonication, extending ultrasonication time caused only small random changes in grain size.
10.12693-APhysPolA.136.411	-1		Total energy calculations based on density functional theory were performed to investigate the physical properties for the austenitic L2(1) and newly calculated martensitic phases of the Cu2AlBe shape memory alloy. When the total energy of all the phases versus the volume data are fitted to the Birch-Murnaghan equation of state, it is seen that the stable martensitic NM, 3M, 5M, and 7M phases of the alloy can exist. The lowest energetic phase was determined as tetragonal non-modulated NM structure. When we compare the energy of the newly calculated martensitic phases to the thermal fluctuation energy barriers (criteria as (3k(B)T)/2 meV/atom is taken), we are confident that the energy difference between 5M, 7M, and 9R phases and the NM phase is large enough to overcome the thermal energy barrier. Moreover, it has been observed that the calculated elastic constants of austenitic L2(1) and martensitic NM, 3M, 5M, 7M, and 9R phases provide all the mechanical stability conditions determined according to crystal structure symmetries. We consider that the phases that exceed the thermal energy barriers and satisfy the mechanical stability conditions can exist at a stable energy level. When the partial electronic density of states (pDOS) of the austenitic and martensitic phases are analyzed, it is seen that the most contribution to the electronic density of states comes from Cu t(2g) and Cu e(g) states. In addition, it is seen that the contributions to the electronic density of state from not only s, p, t(2g) and e(g) states of Al and Be atoms but also s and p states of Cu atom have been observed extremely small quantity in the all austenitic and martensitic phases. On the other hand, the t(2g), and e(g) states of Cu atoms dominate in the electronic nature of the Cu2AlBe shape memory alloy. Cu2AlBe shape memory alloy is a non-magnetic material since all phases of spin-up and spin-down are all symmetrical.
10.12693-APhysPolA.96.197	4	transformation; martensite; martensitic; phase; shape; beta; memory; shape memory; temperature; temperatures; martensitic transformation; gamma; transformation temperatures; effect; thermal	Among the copper base shape memory alloys the most popular are CuZnAl alloys which however show several features like: tendency to stabilisation, limitation of the effect to low temperatures, lattice defects multiplication after numerous cycling and low decomposition temperatures. This defines the directions of investigations of copper base alloys in order to avoid these negative features limiting their applications. In spite of a large number of investigations of several types of alloys like CuAlNi, CuAlMn, CuAlNiMnTi, CuAlAg, CuGa, CuZn and others, the shape memory properties of NiTi base alloys are considered to be superior and actually are used in a majority of applications in spite of a much higher components cost. In this presentation the investigations of superelastic deformation of mono- and polycrystalline CuAlMn alloys will be discussed. Structure changes during pseudoelastic deformation of CuAlMn single crystals were investigated using in situ optical and high voltage electron microscopy. The effects of ageing on the martensitic transformation temperatures in CuZnAl, CuAlMn and CuZnSn alloys and resulting shift of transformation temperatures are discussed based on the transmission electron microscopy studies. They indicate that changes of ordering within beta phase are responsible for an increase, while precipitation of bainite or gamma phase for a decrease in the martensitic transformation temperatures. Ribbons from CuANiMn alloy cast using the melt spinning method, crystallizing at a very high rate, show a large drop of M-s temperatures. This drop of M-s depends upon a wheel speed controlling the solidification rate. It is correlated with the decreasing grain size and its value is much larger for ribbons containing titanium due to its grain refinement capabilities. The two-way shape memory effect may appear after the training performed by a repetitive cooling under external stress and heating after unloading. It is demonstrated that in alloys transforming below 150 degrees C saturation of the two-way shape memory effect occurs between 50 and 80 training cycles.
10.1360-02tb9291	0	solidification; phase; magnetic; magnetic field; undercooling; field; liquid; separation; peritectic; immiscible; cu-; dendrite; phase separation; microstructure; primary	Droplets of Cu-20%Sb hypoeutectic alloy has been rapidly solidified in drop tube within the containerless condition. With the decrease of droplet diameter, undercooling increases and the microstructures of primary copper dendrite refines. Undercooling up to 207 K (0.17 T-L) is obtained in experiment. Theoretic analysis indicated that, because of the broad temperature range of solidification, the rapid growth of primary copper dendrite is controlled by the solutal diffusion. Judging from the calculation of T-0 curve in the phase diagram, it is shown that the critical undercooling of segregationless solidification is DeltaT(0) = 474 K. At the maximum undercooling of 207 K, the growth velocity of primary copper phase exceeds to 37 mm/s, and the distinct solute trapping occurs.
10.1361-105497100770339608	12	thermodynamic; ternary; phase; data; experimental; equilibria; phase equilibria; liquid; binary; experimental data; calculated; phases; literature; model; calphad	Thermodynamic assessments have been made for the Cu-Sb and Sb-Zn binary systems by means of the CALPHAD technique. The Gibbs energies of the liquid, bcc, and fee phases are described by a substitution solution model and a Redlich-Kister formalism, All of the compounds were treated as stoichiometric compounds. Moreover, the liquidus temperatures of the Zn-rich portion in the Sb-Zn system were measured to check the unusual shape reported by previous work. It was confirmed that the liquidus line is not peculiar but smooth . A consistent set of the thermodynamic parameters was optimized to obtain a better fit between calculated results and experimental data including phase diagram and thermodynamic quantities.
10.1361-105497100770339860	12	thermodynamic; ternary; phase; data; experimental; equilibria; phase equilibria; liquid; binary; experimental data; calculated; phases; literature; model; calphad	The thermodynamic activity of rhodium in solid Cu-Rh alloys is measured by the electromotive force method in the temperature range from 1050 to 1325 K with a solid-state cell: Rh, Cu + Cu2O//(Y2O3)ZrO2//Cu-Rh + Cu2O, Rh The activity of copper and the Gibbs energy, enthalpy, and entropy of mixing of the solid solution are derived. Activities exhibit large positive deviation from Raoult's law The mixing properties can be represented by a pseudo-subregular solution model in which excess entropy has the same type of functional dependence on composition as the enthalpy of mixing: Delta H = X-Rh(1-X-Rh)[41,340 + 12,670 X-Rh] J mol(-1) Delta S-E = X-Rh(1-X-Rh)[15.46 + 4.72 X-Rh] J mol(-1) K-1 The results predict a solid-state miscibility gap with T-c = 1408 (+/-5) K at X-Rh = 0.59 (+/-0.02). The computed critical temperature is 15 K lower than that reported in the literature. The coherent spinodal, calculated using Cahn's model, is characterized by T-c' = 983 (+/-5) K and X-Rh' = 0.43 (+/-0.02). The large difference between the coherent and chemical spinodal is caused by the relatively large difference in lattice parameters of Cu and Rh and high Young's modulus of the alloy. The positive enthalpy of mixing obtained in this study contrasts with the negative values predicted by Miedema's model. Thermodynamic properties of liquid alloys are estimated from the data for solid alloys obtained in this study and the approximate location of the liquidus available in the literature.
10.1361-105497100770340183	-1		The Cu-Nb and Cu-Cr alloys at compositions ranging from 5 to 86 wt% Nh (89 wt% Cr) were processed in a clean environment and solidified at relatively low cooling rates of 50 to 75 degrees C/s to determine liquidus temperatures. In this study, both temperature measurements and microstructural observations confirmed the equilibrium phase diagram having an S-shaped, nearly flat liquidus, rather than that with a monotectic reaction in the liquid state. However, a metastable liquid miscibility gap exists in the two systems.
10.1361-105497100770340381	-1		The metastable liquid-phase separation (MLPS) in the Cu-Co-Fe system was investigated using an electromagnetic levitation melting and solidification technique. It was found that when ternary alloys containing more than 10 wt% (12 at%) Co and 10 wt% (11 at%) Fe were undercooled below a certain temperature, T-sep, the homogeneous melt separated into two liquid phases. In alloys containing more than 54 to 57 wt% (49 to 54at,%) Cu (depending on the Co and Fe content), the phase separation generally appeared as dispersed (Fe, Co)-rich droplets (L-1) in a Cu-rich matrix, whereas for alloys containing less copper, the separation resulted in Cu-rich droplets (L-2) in a (Pe, Co)-rich matrix. The metastable liquid miscibility gap boundary of the Cu-Co-Fe ternary was determined using the measured T-sep and the composition of the separated phases. The ternary liquid-phase separated boundaries were found to be consistent with a cross-sectioned phase diagram in which one axis represents pure copper and the other Fe + Co.
10.1361-105497101770332956	13	clusters; atomic; glass; atoms; composition; dynamics; metallic; icosahedral; glasses; simulations; molecular; cu-zr; molecular dynamics; metallic glasses; structural	The thermodynamic properties of metals and alloys are studied using the moment method in the statistical dynamics, which allows us to take into account the anharmonicity of thermal lattice vibrations and size mismatch of constituent atoms, going beyond the quasi-harmonic approximation. Within the fourth-order moment approximation, the free energy and equilibrium lattice spacing of the binary alloys are given explicitly in terms of the effective pair potentials and the second- and fourth-order vibrational constants. The long-range order (LRO) parameter eta and order-disorder transition temperatures (ODTs) T-c of binary alloys are obtained by solving the explicit transcendental equations. The numerical calculations of thermodynamic quantities for Cu3Au and beta -CuZn alloys show that the inclusion of the anharmonicity of lattice vibration plays an essentially important role in determining the phase stabilities of metals and alloys.
10.1361-105497101770332992	-1		The phase equilibria among the alpha (A1), beta (A2), and gamma (D8(3)) phases in the Cu-Al-X systems (X: Ti, V, Mn, Fe, Co, Ni, Zn, Sn, and Sb) at 700 and 800 degreesC were investigated, and the effects of these alloying elements on the phase boundaries, homogeneous solid solution ranges, and tie-lines among the alpha, beta and gamma phases were accurately determined by the diffusion couple method. The phase stabilities among alpha, beta and gamma phases are discussed in terms of the partition coefficient. In addition, a modified Guillet's method, which is used to estimate the effect of alloying elements on microstructure, is proposed by taking into account the change of equivalent coefficient with the phase fraction, and applied to predict the effect of alloying elements on the microstructure of the Cu-Al base alloy.
10.1361-105497102770331163	12	thermodynamic; ternary; phase; data; experimental; equilibria; phase equilibria; liquid; binary; experimental data; calculated; phases; literature; model; calphad	The Cu-In liquid phase exhibits an important short range disordering between the liquidus line and 1100degreesC. Kao et al [1993Kao] have proposed a thermodynamic phase diagram optimization using a constant excess C-P versus temperatures in the liquid phase, which seems unrealistic for low and high temperatures far extrapolations. On the contrary, we suggest in this new model to use a description of the liquid phase without any excess C-P: the considered liquid phase is modelized only with high temperatures experimental data and the disordering enthalpy of the liquid is added to the melting enthalpy of the various solid phases. This artefact allows to correctly modelize the complete phase diagram using all the, available thermodynamic data for formation of the solid phases.
10.1361-105497102770331352	12	thermodynamic; ternary; phase; data; experimental; equilibria; phase equilibria; liquid; binary; experimental data; calculated; phases; literature; model; calphad	On the basis of thermodynamic properties and phase diagram data, the Cu-In binary system was thermodynamically assessed. The phases in this system were modeled using the Redlich-Kister expression for the Gibbs energies of the solution phases, adopting three-sublattice models for gamma and eta', and assuming stoichiometric compounds for other intermetallic phases. Then a set of consistent parameters was obtained by the CALPHAD method, by which reasonable agreement can be realized between the thermodynamic properties for various phases and phase relations of this system.
10.1361-105497103770330532	-1		The effect of aluminium on the equilibrium phases of the Cu-Zn alloys has been studied within the range of chemical compositions of interest to brass producers. Ternary alloys were cast by melting two Cu-Zn base alloys (with similar to59.5% and similar to61.2 wt% Cu) followed by the addition of aluminium up to 3.68 wt%. Isothermal homogenization, followed by rapid cooling, has been used to determine the equilibrium phases at different temperatures. The alloys have been observed by scanning electron microscopy (SEM) and the respective chemical analysis determined by electron probe microanalysis (EPMA). Statistical analysis of the results enables a correlation of the chemical compositions of the equilibrium phases with temperature within composition range of the study.
10.1361-105497103770330541	12	thermodynamic; ternary; phase; data; experimental; equilibria; phase equilibria; liquid; binary; experimental data; calculated; phases; literature; model; calphad	In this work, the Cu-Zn system was explored for alloys in the zinc-rich part above 90 at% zinc between 643 and 843 K by electromotive force measurements. Modeling was then done and was based on the generally well-accepted description of the binary system as in the last assessment proposed by Kowalski and Spencer [1993Kow] taking into account recent thermodynamic data available in literature. The resulting optimized coefficients are in good agreement with experimental observations.
10.1361-105497105X56089	-1		Isochronal annealing was carried out for cast Cu, Cu-5wt%Al, Cu-10wt%Al, and Cu-20wt%Al alloys in the range of 423-1173 K. The annealing behavior was followed by positron annihilation lifetime spectroscopy (PALS). Microhardness (H,) has been measured and used for comparison. The microstructure variations were observed by optical and scanning electron microscopy. Three stages were distinguished for all samples in the behavior of average lifetime (tau(av)) and H-v. In the first stage (room temperature to 573 K), tau(av) and H-v reach extremely high values for Cu-20wt. % Al compared with other alloys. The analysis of the first stage indicates anneal softening for cast Cu and Cu-5wt%Al and anneal hardening for Cu-10wt%Al and Cu-20wt%Al. The second stage (573-873 K) is characterized by a maximum of tau(av) at 673 K followed by a decrease up to the end of the stage for cast Cu, Cu-5wt%Al (the highest maximum), and Cu-10wt%Al; a slight change is observed for Cu-20wt%Al. The change in H, is notable only for Cu-10wt%Al and Cu-20wt%Al, and indicates that tau(av) is sensitive to the change that occurred in the bulk material, while HV shows the general behavior of the surface of the material. The third stage (873-1173 K) is characterized by near saturation for both tau(av) and H-v, indicating complete recrystallization for cast Cu, Cu-5wt%Al, and Cu-10wt%Al and complete softening for Cu-20wt%Al. Recrystallization is shifted to higher temperatures by increasing the amount of Al in Cu. The analysis of positron lifetime presents evidence of the existence of three-dimensional (3D) defects in addition to one-dimensional defects, so a modification to the simple trapping model is needed when considering inhomogeneous trapping.
10.1361-105994900770345476	6	grain; deformation; strain; strength; dislocation; cu-; tensile; size; ecap; grain size; sfe; ductility; hardening; high; stress	A phosphorus-containing Cu-0.6 wt% Cr alloy was solution treated and then aged using various combinations of time and temperature. The influence of aging time and temperature on microstructures and properties of this alloy was investigated by means of an analytical transmission electronic microscope (TEM) and measurements of hardness and electrical conductivity, It was found that neither underaging nor overaging could harden the alloy significantly. The microstructure corresponding to peak hardness was characterized by very fine and coherent precipitates. Increasing aging time and temperature caused the precipitates to grow into rodlike incoherent Cr particles having body-centered cubic (bcc) crystal structure, but aging temperature influenced the microstructures and properties more intensively than did aging time. Undissolved body-centered tetragonal (bct) Cr3P particles, which were found in both as-solution-treated and as-aged structures, were not harmful to electrical conductivity and might act as obstacles impeding dislocation motion. As compared to a Cu-0.65 wt. % Cr alloy not containing phosphorus, the studied alloy needs aging at a higher temperature to reach peak hardness.
10.1361-105994900770345971	-1		Changes in compositions and microstructures in the surface layer of a Cu-Zn-Al shape memory alloy during friction were investigated by means of scanning electron microscopy, electron probe microanalysis (EPMA), X-ray diffraction, and transmission electron microscopy, It has been found that in friction, single M18R martensite beta' transforms into alpha + beta, with the shape and distribution of the new phases varying,vith the conditions of friction. In mild friction, Zn and Al diffuse over short distances along the sliding direction, resulting in a structure in which needlelike beta and alpha alternate along the sliding surface. In severe friction, where higher surface temperatures and temperature gradients are expected, Zn and Al make long-distance uphill diffusion from inside toward the surface. Consequently, Zn and Al are concentrated on the surface and depleted in the subsurface, and the phase layers present from the outmost surface inward are beta, alpha, alpha + beta, cross-martensite, and the matrix.
10.1361-105994902770343890	6	grain; deformation; strain; strength; dislocation; cu-; tensile; size; ecap; grain size; sfe; ductility; hardening; high; stress	The microstructure and properties of a Cu-0.55 wt% Cr-0.07 wt% P alloy were studied by using optical microscopy, transmission electron microscopy, and the measurements of Vickers hardness and electrical conductivity after it was subjected to conventional aging and two thermomechanical treatments. The hardness increment resulting from the thermomechanical treatments was 50% higher than the increment produced by conventional aging. The thermomechanical procedure, including two aging steps (double aging), produced a 5% International Annealed Copper Standard (IACS) higher increase in conductivity than the procedure including a single aging step. However, the former procedure did not lead to more efficient hardening in the studied alloy than the latter procedure because during the second aging step extensive recovery or even the onset of recrystallization tended to suppress precipitation hardening to some extent. After being subjected to a thermomechanical treatment that included three cold-drawing steps and one aging step, the studied alloy showed a tensile strength of 550 MPa with a conductivity of 74% IACS. Based on the obtained results as well as on the comparison with other Cu-Cr type alloys, some suggestions were given for improving the thermomechanical processing route of the studied alloy.
10.1361-105994902770343926	5	materials; thermal; heat; properties; material; welding; sintering; fusion; strength; laser; heat sink; thermal conductivity; mechanical; sink; manufacturing	C 38500 is a widely used copper alloy with a great variety of applications from decoration and architecture to mechanical/electrical engineering. The chemical composition of this alloy offers superior machinability and subsequently increased productivity in high-speed machining and manufacturing processes. In European countries, this alloy is used primarily as free cutting brass (CW 614N according to EN 12164: 1998), similar to C 36000 alloy, which is used also for thread rolling. The lower percentage of Cu compared to C 36000 (nominal 58% instead of 61%) decreases the cost of the raw materials. This paper reports the principal aspects of microstructure, mechanical properties, and machinability of this alloy in relation to the industrial manufacturing process used.
10.1361-105994903770343169	16	wear; composite; composites; powders; milling; particles; powder; wt; sliding; friction; hardness; matrix; mechanical; surface; properties	The wear behaviors of nanocrystalline Cu-Zn alloy were investigated. Sliding wear tests were performed on a pin-on-disk test machine under dry conditions. Results indicated that nanocrystalline Cu-Zn alloy annealed at 300 degreesC exhibited better wear resistance and high load-bearing capacity than those in the as-pressed state. A surface film almost covering the entire worn surface was formed for nanocrystalline Cu-Zn alloy annealed at 300 degreesC at a load range from 2.1-5.6 MPa. The surface film effectively improves the wear resistance of nanocrystalline Cu-Zn alloy.
10.1361-10599490524002	-1		It is known that the strength of a metal can be successfully improved by rapid solidification. The hardness of the rapidly solidified Cu-Cr-Sn-Zn alloy is much higher than that of the solution heat-treated and aged alloy. In this study, multiple-layer, feed-forward, artificial neural network (ANN) modeling has been used to study the hardness and electrical conductivity behavior of a rapidly solidified Cu-Cr-Sn-Zn alloy. The ANN model shows how the aging parameters influence the hardness and electrical conductivity of a rapidly solidified Cu-Cr-Sn-Zn alloy. The ANN modeling also provides encouraging predictions for information not included in the trained set samples, indicating that a backpropagation network is a very useful and accurate tool for property analysis and prediction.
10.1371-journal.pone.0165058	12	thermodynamic; ternary; phase; data; experimental; equilibria; phase equilibria; liquid; binary; experimental data; calculated; phases; literature; model; calphad	The Cu-Li-Sn phase diagram was constructed based on XRD and DTA data of 60 different alloy compositions. Eight ternary phases and 14 binary solid phases form 44 invariant ternary reactions, which are illustrated by a Scheil-Schulz reaction scheme and a liquidus projection. Phase equilibria as a function of concentration and temperature are shown along nine isopleths. This report together with an earlier publication of our group provides for the first time comprehensive investigations of phase equilibria and respective phase diagrams. Most of the phase equilibria could be established based on our experimental results. Only in the Li-rich part where many binary and ternary compounds are present estimations had to be done which are all indicated by dashed lines. A stable ternary miscibility gap could be found which was predicted by modelling the liquid ternary phase in a recent work. The phase diagrams are a crucial input for material databases and thermodynamic optimizations regarding new anode materials for high-power Li-ion batteries.
10.1504-IJSURFSE.2013.057611	-1		In this research paper, copper coatings were successfully deposited on Ni alloy (ASTM B 435) substrate using cold spray process with an aim to avoid the contact of dissimilar materials frequently encountered in industrial applications. The coatings were deposited using air as carrier gas by varying process parameters, i.e., powder feed type, stagnation temperature, stagnation pressure and stand-off distance. The deposited coatings were characterised using the combined techniques of XRD, FESEM, EDS and EPMA. EDAX, XRD and EPMA. It is found that the main constituent in the coating is Cu which resembles the sprayed powder used for the study. The developed coatings have a uniform and dense microstructure, with uniform hardness value in the range of 108-140 HV, average coating thickness 13-58 mils and average surface roughness 6-11 mu m. A very small fraction of phases of other elements have formed in the microstructure of the coating in the form of either inter-splat lamellae or globules.
10.1515-amm-2016-0158	6	grain; deformation; strain; strength; dislocation; cu-; tensile; size; ecap; grain size; sfe; ductility; hardening; high; stress	The aim of the present paper was to investigate microstructure and texture evolution of two single crystals and polycrystal of Cu-8.5%at. Al material. All of mentioned samples were deformed by HE to achieve true strain epsilon = 1.17. For microstructure analyzes observations by transmission electron microscope (STEM) were done. Crystalline size for samples after SPD were determine using XRD method. The global texture measurements were done using Bruker D8 Discover diffractometer equipped in Cr radiation. Microstructure investigations revealed nanocrystalline structure in single crystals with initial orientations < 110 > and < 100 > and polycrystalline Cu-8.5%at. Al material after SPD. The global texture measurements have shown the stability of initial orientation of < 100 > Cu-8.5%at. Al single crystal after HE, whereas the same SPD process strongly brakes up the orientation < 110 > Cu-8.5% at. Al single crystal.
10.1515-amm-2017-0360	-1		The paper presents analysis and assessment of operating power of vacuum induction furnace in relation to the efficiency of lead removal from Cu-Pb alloy in VIM (vacuum induction melting) technology. Thermodynamic analysis of the process is performed as well.
10.1515-corrrev-2016-0053	2	corrosion; surface; film; electrochemical; films; spectroscopy; layer; current; solution; potential; resistance; composition; x-ray; ions; showed	The corrosion behavior of Cu-Zn-Al alloys modified with Fe, B, and Fe-B was investigated. This was motivated by the need to verify the effect of microalloy additions on the corrosion behavior of Cu-Zn-Al alloys, which, as recent study suggests, impacts microstructural changes other than grain refinement. Cu-Zn-Al alloys were produced by casting method with and without the addition of microalloy elements. The alloys were subjected to thermomechanical treatment before machining of test samples for corrosion and microstructural analysis. Scanning electron microscopy (SEM) and polarization electrochemical technique were used for the study. From the results, increase in grain size and change in grain edge morphology was apparent for the modified Cu-Zn-Al alloys produced. In 3.5 wt% NaCl and 0.3 (M) H-2 SO4 solutions, the corrosion current densities were dependent on the type and concentration of the microalloy addition. Essentially, the corrosion rates for the modified alloys were higher in 3.5 wt% NaCl solution; in 0.3 m H-2 SO4 solution, the modified Cu-Zn-Al alloy grades were observed to be more resistant to corrosion. The corrosion mechanisms of the alloys in both solutions were not feasibly established from the SEM images, but the extent of corrosion product deposition was apparent.
10.1515-corrrev-2022-0025	2	corrosion; surface; film; electrochemical; films; spectroscopy; layer; current; solution; potential; resistance; composition; x-ray; ions; showed	The amperometric biosensor was created using a flat sheet of the Cu-Zn-Al shape memory alloy, with a shiny surface and uniform thickness below 1 mm. The high biocompatibility and a large specific surface area for enzyme loading are evaluated. In vitro biomedical corrosion testing of samples revealed successful immobilization of catalase, which has undergone quasi-reversible electron transfer from the surface and saline solution. A catalase that had been immobilized retained its basic structure and bioactivity and demonstrated a remarkable electrocatalytic response to hydrogen peroxide reduction. The reduction of hydrogen peroxide on the catalase-modified Cu-25.38Zn-3.3Al alloy was investigated using hydrodynamic amperometry in both the absence and presence of L-cysteine and K-2[B3O3F4OH] inhibitors. Catalytic reduction currents have increased as a result of the gradual increase in hydrogen peroxide concentration. The study on enzyme activity inhibition has shown a lower corrosion rate of catalase-modified bioalloy than the initial sample because inhibitor ions occupy all sites of the immobilized enzyme.
10.1515-corrrev-2023-0153	2	corrosion; surface; film; electrochemical; films; spectroscopy; layer; current; solution; potential; resistance; composition; x-ray; ions; showed	The corrosion behavior of Cu-40Zn alloy in a periodic service between simulating atmospheric and deep sea environment has been systematically studied. Results showed that a layer of protective corrosion products can be formed quickly and become defective over time. During the periodic service, the HP (high hydrostatic pressure) promotes the anodic dissolution of the base and the generation of (Cu, Zn)2(OH)3Cl, which causes expansion of the corrosion products; the AP (alternating pressure) facilitates the wetting process during dry to wet stage, and the alternating force caused by AP leads to the cracks, peeling off of the corrosion products. Severe intergranular corrosion takes place, which initiates at the beta phase and is accelerated by the combination of defective corrosion products and the drying stage.
10.1515-htmp-2012-0161	16	wear; composite; composites; powders; milling; particles; powder; wt; sliding; friction; hardness; matrix; mechanical; surface; properties	Two copper based composites: an experimental Cu-Al2O3 and commercial GlidCop AL-60 grade (with 1.1 wt% Al2O3) with grains size approximately 1-2 mu m were treated by Equal Channel Angular Pressure (ECAP) technique in order to induce severe plastic deformation and to reduce the grain size by about an order of magnitude. Microstructure of the as-received and ECAPed states of both systems were observed. Hardness of the experimental materials was measured by instrumented indentation. Tribological properties were studied by pin-on-disk technique in dry sliding against a steel ball at a various temperatures from room temperature up to 873 K. For all systems the coefficient of friction and specific wear rates were evaluated. Worn surfaces were studied by scanning electron microscopy and level of oxidation was measured using EDX spectrometry. It was found that between 473 K and 673 K the coefficient of friction decreased significantly. At lower temperatures the finer grained systems were more wear resistant than the as-received ones. The wear rate of all systems decreased down to zero at 673 K due to formation of hard oxide rich layers. Damage mechanisms were identified and their relationship with structural characteristics was inferred.
10.1515-htmp-2016-0131	0	solidification; phase; magnetic; magnetic field; undercooling; field; liquid; separation; peritectic; immiscible; cu-; dendrite; phase separation; microstructure; primary	High magnetic field (HMF) and solidification processes were changed during the solidification of both Cu-28 mass% Ag and Cu-72mass% Ag alloys. The results indicated that the eutectic morphology in Cu-Ag alloys was affected by HMF, composition and solidification parameters. The lamellar spacing of Cu-28 mass % Ag alloy solidified by furnace-cooling was refined by the application of HMF owing to the decreased diffusion coefficient in mushy zone. The lamellar spacing in both Cu-28 mass % Ag sample held at the eutectic temperature and Cu-72 mass % Ag sample by slow controlling cooling was increased by HMF, which might be attributed to the dominated thermolectro-magnetic convection. The lamellar spacing in Cu-72 mass % Ag alloyswas increased comparedwith that of Cu-28mass % Ag alloys because of the decreased growth rates. In Cu-28 mass % Ag alloy, however, fluid transverse velocity gradient was dominate rather than the growth rate and the imposition of HMF had reverse influences on the lamellar spacing. The lamellar-rod transition of Cu phase was promoted by HMF because of the increased Cu volume fraction in eutectic component. These results shed light on the dependence of eutectic morphology in Cu-Ag alloys on composition, external high magnetic field and solidification parameters.
10.1515-htmp-2020-0045	-1		In this work, the influence of pulse frequency on the corrosion resistance of Cu-Zn binary alloy has been investigated by using electrochemical workstation, scanning electron microscope and X-ray diffraction. The results have shown that after the electric pulse treatment, the average grain size in the microstructure of high-zinc binary brass decreased and the corrosion resistance increased. The thickness of dezincification layer decreased from 49.8 to 30.8 mu m. The diameter of capacitive reactance arc increased from 741.1 to 2898.0 mu m. The corrosion potential increased from -0.2719 to -0.2378 V, and the corrosion current density decreased from 6.3147 x 10(-6) to 4.6971 x 10(-7) A cm(-2) by one magnitude order.
10.1515-htmp-2021-0039	-1		The effects of high-density electric current pulse (ECP) treatment on the solidification of Cu-37.4 wt% Pb monotectic alloy melt were investigated. Compared to the method of molten glass purification combined with cyclic superheating, ECP treatment created finer microstructures of Cu-Pb alloys, with more homogeneous distribution of the Pb phase in the matrix. This phenomenon can be explained by the cluster theory for liquid metals and the non-equilibrium diffusion theory. First, ECP treatment could cause the fission of larger atomic clusters to increase the undercooling that enabled a large number of smaller clusters to grow and reach the critical nucleation radius. Second, ECP treatment could reduce the diffusion energy barrier to enhance the non-equilibrium diffusion of solute atoms and suppress the segregation of Pb.
10.1515-ijmr-2020-8002	-1		The Cu-12.5Ni-5Sn-xFe alloys were prepared using powder metallurgy. The effect of the amount of Fe addition on the microstructure and mechanical characteristics of Cu-12.5Ni-5Sn-xFe alloys was investigated. The microstructure and morphology of alloys were examined by means of X-ray diffraction, scanning electron microscopy and cold field emission scanning electron microscope. Results indicate that the hardness and yield strength of the Cu-12.5Ni-5Sn alloy are improved by addition of trace amounts of Fe. The lamellar precipitates of Cu-12.5Ni-5Sn-xFe alloys are more and finer compared to those of Cu-12.5Ni-5Sn alloy. Fe can facilitate the aging process and strengthen the effect of aging-hardening.
10.1515-ijmr-2021-8677	-1		In this study, the microstructure and mechanical properties of a Cu-rich multiple-principal-element alloy with the composition (Cu50Ni20Cr20Mn10)(95)Al-5 (at%) were investigated. It was found that after 900 degrees C/1 h annealing process, the as-cast alloy has achieved promising mechanical properties with a yield stress of 510 MPa, an ultimate tensile stress of 820 MPa and tensile elongation of 30 %. These properties are superior to those of traditional nickel-aluminum bronze (NAB) alloys. Moreover, the as-annealed alloy exhibited much better anti-corrosion properties with respect to the NBA alloys. Transmission electron microscopy observations showed that high-number-density nano-scaled L1(2)-type ordered particles have precipitated in the Cu-rich phase after heat treatment and this was regarded as the main mechanism responsible for the enhancement of yield stress.
10.1515-ijmr-2023-0174	-1		Diffusion of Bi and Ag in a series of polycrystalline Cu-Bi alloys is investigated using a radiotracer technique and applying the 207Bi and 110m Ag isotopes, respectively. Together with the previous measurements (Divinski S., Lohmann M., Herzig C., Straumal B., Baretzky B., Gust W. Grain-boundary Melting Phase Transition in the Cu-Bi System. Phys. Rev. B 2005, 71, 104104), a temperature-concentration interval of strong, by orders of magnitude, enhancements of Bi grain boundary diffusion rates is distinguished and the results are interpreted in terms of a grain boundary pre-wetting/wetting phase transition. Grain boundary diffusivity of Ag exhibits as well a step-wise increase with rising Bi content, mirroring the behaviour observed for the Bi tracer. However, contrary to the Bi tracer atoms for which grain boundary enhancement is observed at about 60 ppm of Bi in Cu-Bi alloys, this transition is revealed by the Ag tracer atoms at a significantly higher concentration, specifically between 90 and 100 ppm of Bi at 1080 K. The Ag diffusion rates in alloys with a moderate Bi content turn out to be not affected by the Bi-induced grain boundary phase transition and the measured grain boundary diffusion coefficients of Ag are nearly the same as those determined for pure polycrystalline Cu. This spectacular result suggests a strong heterogeneity of Bi segregation and Bi-induced phase transition for general high-angle grain boundaries in a given alloy. The behaviour is discussed in terms of the extrinsic grain boundary defects and their impact on mechano-chemical coupling which is accompanying the grain boundary phase transitions.
10.1515-mt-2022-0270	16	wear; composite; composites; powders; milling; particles; powder; wt; sliding; friction; hardness; matrix; mechanical; surface; properties	Dry friction and wear behavior at high temperatures was investigated against an Al2O3 ball in order to characterize the wear rate, coefficient of friction (COF), hardness and thermal friction behavior at different temperatures in the wear-treated zones of the CuCrZr copper alloy. Experiments were fulfilled using a pin-on-disk wear device with the aid of a temperature modulated wear device at room temperature, 100, 200 and 300 ?. The loads applied during wear are given as 3N, 5N and 7N, respectively. In order to examine the morphological structure of the worn surfaces, appropriate samples were prepared and SEM (scanning electron microscopy) device was used. Similarly, EDS (energy dispersive x-ray spectrometry) was applied to worn surfaces to examine the abrasive-material interaction. Against the hardness of the material at 25 ?, the hardness value in measurements at 300 ? showed a small increase. The COF value increased at 100 ? and then decreased, while the wear rate increased significantly as the temperature increased. The temperature increase starting from RT up to 300 ? weakened the internal structure of the CuCrZr alloy and caused an increase in the wear rate. XRD test was used to show the phases that may occur in CuCrZr alloy due to temperature and heat treatment.
10.1515-ntrev-2020-0108	15	aging; strength; conductivity; electrical conductivity; electrical; mpa; treatment; strengthening; degrees; cu-; cold; precipitation; tensile strength; tensile; iacs	The Cu-20 wt% Ag alloy wire rod was prepared using three-chamber vacuum cold mold vertical continuous up-casting followed by multi-pass continuous drawing. The evolution of microstructure, mechanical property, and electrical property of the Cu-20 wt% Ag alloy wire during multi-pass continuous drawing was studied. After multi-pass continuous drawing, the continuous network eutectic structure in the longitudinal section of the as-casted rod was gradually drawn into long fibers that approximately parallel to the axial direction, while the space of the continuous network eutectic structure in the transverse section is getting smaller and smaller. Both the preferred orientation of copper and silver grains are (1,1,1). With the increase of drawing strain (eta), the tensile strength of Cu-20 wt% Ag alloy wire gradually increases while the elongation gradually decreases. When the diameter is drawn to 0.02 mm (eta = 11.94), the tensile strength of the alloy is 1,682 MPa and elongation is 2.0%. The relationship between tensile strength, elongation, and diameter conforms to Allometric and Boltzmann functions, respectively.
10.1515-ntrev-2022-0500	15	aging; strength; conductivity; electrical conductivity; electrical; mpa; treatment; strengthening; degrees; cu-; cold; precipitation; tensile strength; tensile; iacs	Cu-Cr-Ti alloy with gradient properties was prepared at 960 degrees C for 2 h in air, 80% cold rolling, and then aging at 500 degrees C for 1 h . The results showed that the surface layer of Cu-Cr-Ti alloy had achieved a good match of electrical conductivity (96.2% International Annealed Copper Standard (IACS)), thermal stability (softening temperature of 650 degrees C), and wear resistance (friction coefficient of 0.17). Meanwhile, the core region maintains high tensile strength (519 MPa) and good electrical conductivity of 71.8% IACS. Transmission electron microscope characterization revealed that the precipitates of surface layer are composed of Cr oxides, complex oxides formed by Cu, Cr, and O, and Ti-rich phases. The existence of oxide particles with discontinuous distribution and stable properties is the reason for the good electrical conductivity, excellent thermal stability, and outstanding wear resistance of the surface layer. The main precipitates of the core are Cr. The high tensile strength of the core is ascribed to the aging strengthening effect of these fine Cr particles. This work provides ideas and approaches for the preparation of copper alloy with excellent properties for high-speed railway contact wire, and solves the drawbacks of composites synthesized from heterogeneous materials.
10.1515-rams-2018-0020	-1		Cu-Cr-Zr alloys provide an excellent combination of strength and electric conductivity and are frequently used as engineering materials in various electric/electronic devises. The present review deals with the microstructural design of Cu-Cr-Zr alloys, their alloying concept, thermo-mechanical processing based on technique of severe plastic deformation, physical mechanisms responsible for high strength and electric conductivity. The influences of microstructure and a dispersion of secondary phases on the mechanical properties and electric conductivity are discussed in detail. First, precipitation sequences during aging that leads to depletion of Zr and Cr solutes from Cu solution are critically reviewed in close connection with interaction mechanisms between dislocations and particles. Then, the main structure-property relationships of Cu-Cr-Zr alloys are considered. Finally, the strengthening of Cu-Cr-Zr alloys through severe plastic deformation by means of submicrocrystalline/nanocrystalline structure and increasing dislocation density as well as the effects of post-deformation heat treatment on the mechanical and electric properties are discussed.
10.1515-rams-2020-0045	5	materials; thermal; heat; properties; material; welding; sintering; fusion; strength; laser; heat sink; thermal conductivity; mechanical; sink; manufacturing	An increase in the service life of electrical products from copper and its alloys is directly related to an increase in the wear resistance of materials. Structural refinement and alloying with cadmium are known to have a positive effect on the strength characteristics and wear resistance of copper, which makes it possible, with a Cd content of 1% by weight, to increase the wear resistance of copper several times, but cadmium is considered an environmentally unsafe element. In this regard, the paper presents the results of studies of a widely used Cu-Cr-Zr alloy system in the ultrafine-grained (UFG) state, micro-alloyed with cadmium (0.2%, weight), in order to improve physical, mechanical, and operational properties, as well as environmental safety. Severe plastic deformation, providing structure refinement to similar to 150 nm, and microalloying with cadmium of a Cu-Cr-Zr system alloy, after a complete processing cycle, provides a tensile strength of 570 +/- 10 MPa and 67% electrical conductivity. At the same time, the abrasion resistance increases by 12 and 35% relative to the industrial systems Cu-Cd and Cu-Cr-Zr, respectively. The obtained characteristics are very promising for improving the operational properties of continuous welding tips, collector plates, and contact wires operating under conditions of intense wear.
10.1515-rams-2021-0038	-1		Copper alloy rod billet with 20% silver was prepared using homemade three-chamber vacuum cold-type vertical continuous casting equipment. The variation rules of the microhardness, eutectic ratio, and size and distribution of silver particles precipitated in the primary alpha-Cu phase at the end of the continuous casting alloy rod blanks were studied using a microhardness tester and scanning electron microscope. The obtained results show that when the cold-type vertical continuous casting speed is 120 mm.min(-1), there is obvious reverse segregation of solute element near the end of the prepared (sic)7.8 mm copper-silver alloy rod blank. From the end of the continuous casting alloy rod blank to 5mm from the end, the Cu-Ag eutectic structure in the copper-silver alloy increases from 13.4 to 15.9%, and the size of Ag particles precipitated in the primary alpha-Cu phase increases from 100 to 350 nm. The microhardness increases from 56 HV0.05 to 85 HV0.05. When the distance from the end exceeds 5 mm, the microstructure and properties of the continuous casting alloy rod blank are basically stable.
10.1515-rams-2022-0297	-1		The main aim of the current work is to investigate the effect of equal channel angular pressing (ECAP) processing parameters, namely, number of passes, ECAP die angle, route type, and processing temperature on the mechanical and electrical properties of pure copper (Cu). The finite element method was used to simulate the homogeneity of stress and plastic strain distribution during ECAP processing. The response surface methodology (RSM) was used to identify the optimum ECAP processing parameters by analyzing the impact of ECAP conditions on responses. A second-order regression model and analysis of variance were created to analyze the ECAP condition of optimum responses. A genetic algorithm (GA) was also applied to optimize the ECAP condition. Finally, a hybrid RSM-GA was created to improve the optimization of ECAP responses and corresponding conditions evaluated using GA. The developed models were validated and compared with the experimental findings to prove that they are reliable as predictive tools. The optimization findings revealed that route Bc was more effective in improving the hardness, yield stress, ductility, and impact energy whereas route A was more effective in improving the ultimate tensile strength and the electrical conductivity of the Cu billets. Furthermore, the optimum die angle, number of passes, and processing temperature for the mechanical and electrical properties were also identified individually.
10.1515-secm-2012-0147	-1		The 0.3%Y2O3/0.3%La2O3/0.3%Al2O3/Cu composite was prepared by oxygen and nitrogen atomization spray deposition technique, internal oxidation, and then treated by annealing at different temperatures. Physical properties such as microstructures, fracture appearance, hardness, strength, electrical conductivity, and arc erosion surface of the composite were investigated. The experimental results show that with an increase in the annealing temperature, the grains of the composite grow up obviously and the electrical conductivity of the composite increases gradually, while the hardness and the tensile strength decrease. When the annealing temperature reaches 1000 degrees C, the matrix grains begin to appear as annealing twins. The tensile fracture morphology of the composite that has been treated by annealing at 700 degrees C for 2 h shows a huge number of large and deep dimples, in which the metallic oxide particles exist. The fracture mode of the composite is the microporous polycondensation plastic fracture. The arc erosion surface shows a large number of paste-like coagulum and bubbles.
10.1515-zpch-2016-0886	2	corrosion; surface; film; electrochemical; films; spectroscopy; layer; current; solution; potential; resistance; composition; x-ray; ions; showed	Protection of metals from being damaged under the effect of corrosion occurs by several methods like the addition of alloying elements or inhibitors. A new family of some nonionic surfactants based on tolyltriazole derivatives (TTAs) having various ethoxyl chain lengths were prepared and their chemical structure was elucidated by using different spectroscopic techniques (FTIR and 1H-NMR). The corrosion inhibition capability of these surfactants [TTA, TTA (12) and TTA (24)] was investigated on two Cu-ternary alloy surfaces (Cu-10Al-10Ni and Cu-10Al-10Zn) in seawater by potentiodynamic polarization and electrochemical impedance spectroscopy measurements. The results revealed that ethoxylated tolyltriazole compounds, TTAs, inhibited corrosion of Cu-ternary alloys in the investigated sea water environment, yielding maximum inhibition efficiencies of 92 % and 91 % for Cu-10Al-10Ni and Cu-10Al-10Zn, respectively. The corrosion and corrosion inhibition behavior of the Cu alloy specimens were influenced by the metal composition and microstructure. The presence of inhibitors and increase of concentration greatly decreases corrosion rate, parameters determined from polarization curves and EIS plots show that inhibitors decrease both cathodic and anodic current densities, suppressing charge transfer processes by adsorption on alloy surface. The corrosion inhibition process is based on the adsorption of the TTAs molecules on the alloy surface, and the adsorption follows the Lang-muir adsorption isotherm. The free energy of adsorption of the different tolyltriazole derivatives on the alloy surfaces was in the range of approximate to -38 kJ mol(-1), which reveals a strong physical adsorption of the inhibitor molecules on the metallic surface. SEM/EDX studies confirmed that TTA inhibitors could protect Cu alloys by adsorption on the alloy surface.
10.1557-JMR.2000.0274	6	grain; deformation; strain; strength; dislocation; cu-; tensile; size; ecap; grain size; sfe; ductility; hardening; high; stress	The yield strength of Cu-Nb filamentary microcomposites was predicted as a function of Nb content by modifying the barrier strengthening model. To predict the variation of the yield strength with Nb content, the interfilamentary spacing was calculated as a function of Nb content on the basis of the assumption that Nb filaments are distributed regularly along the sides of triangular unit cells. The yield stress can be described as the sum of the substructural strengthening component and the filament boundary strengthening term. The good agreement between the prediction and the experimental data suggests that the strength increase in Cu-Nb filamentary microcomposites with increasing Nb content results mostly from increasing the volume fraction of Nb filaments, which act as barriers to plastic flow.
10.1557-JMR.2002.0203	-1		The new generation of semiconductor metallization is based on Cu-film technology. In this paper we report on detrimental changes in surface morphology of self-passivated Cu-1 at% Al films which were magnetron-sputtered on Si substrates. Large voids appeared at grain boundaries after annealing, oxidation at temperatures at or above 500 degreesC, and cooling to room temperature under vacuum. Grain-orientation imaging with electron backscatter diffraction revealed that preferentially high-energy grain boundaries were voided. Contrary to reports in the literature, void growth was not prevented by the extremely clean ultrahigh-vacuum conditions during film fabrication nor by the strong and very sharp grain texture. Instead, it was clearly correlated with the stable surface oxide on the self-passivated films. Void growth was not found after annealing passivation-free films such as pure Cu or unoxidized Cu-1 at% Al films.
10.1557-JMR.2003.0276	-1		High-current-density electropulsing was applied to a coarse-grained Cu-Zn alloy with two phases of alpha-phase and beta'-phase. It was found that with an electropulsing treatment, ultrafine-grained (UFG) microstructure could be formed in the a-phase, but could not be formed in the beta'-phase. The results indicated that the formation of UFG microstructure was dependent on solid-state phase transformation. The main reason for the formation of UFG microstructure by electropulsing treatment resulted from the effect of a decrease in thermodynamic barrier and enhancement of nucleation rate in a current-carrying system, but not from the high heating and cooling rate during electropulsing treatment. The bulk UFG samples prepared by electropulsing treatment were free of porosity and contamination and had no large microstrain. It was reasonable to anticipate that a new method might be developed to produce ideal bulk UFG samples directly from the conventional coarse-grained materials by application of electropulsing.
10.1557-JMR.2006.0120	-1		Copper segregation in a subsurface layer during annealing of Cu60Zr30Ti10 bulk metallic glass at 773 K under oxygen atmosphere has been investigated by x-ray diffraction, Auger electron spectroscopy, x-ray photoelectron spectroscopy, and scanning electron microscopy. The formation of metallic copper is strongly dependent on the annealing environment. Various oxides with metallic copper are formed after annealing in oxygen atmosphere, but only crystalline intermetallic phases are found under vacuum annealing. Besides, surface characterization results show that the sample annealed in oxygen and vacuum result in enrichment and depletion of Cu on the surface region, respectively.
10.1557-JMR.2007.0063	-1		We synthesized bulk amorphous alloy systems of Cu43Zr43Al7X7 (X = Be, Ag; numbers indicate at%), with the objective of simultaneously enhancing the glass-forming ability (GFA) and the plasticity. The alloys not only exhibit high plasticity (similar to 7%, similar to 8%), but also possess enhanced GFA (alloys with 12 and 8 mm diameter). The possible mechanisms underlying this enhanced GFA and plasticity exhibited by these alloys are discussed based on the atomic-packing state and atomistic-scale compositional separation associated with the mixing enthalpy difference. A strategy for designing bulk amorphous alloys with simultaneous improvement in the GFA and the plasticity is proposed from the viewpoint of atomic-packing state and atomistic-scale phase separation.
10.1557-JMR.2008.0329	-1		Laser Engineered Net Shaping (LENS (TM)) is a laser-assisted manufacturing process that offers the possibility of producing metallic coatings and components with highly nonequilibrium microstructures. In this work, the microstructure developed by LENS deposition of Cu47Ti33Zr11Ni8Si1 powder on a bulk metallic glass substrate, with nominal composition Zr58.5Nb2.8Cu15.6Ni12.8Al10.3, is investigated. Single-layer deposition results in the formation of an inhomogeneous but partially amorphous layer above a crystalline heat-affected zone. Elemental analysis of the deposited layer indicates incomplete mixing of the powder with the melt pool. The as-deposited alloy exhibits a single glass transition event and its primary crystallization event is consistent with the first crystallization temperature of the Cu-based powder. Subsequent remelting of this layer results in a still partially amorphous deposit with a uniform composition of (Zr + Nb)(51.8)Cu24.7Ti3.4Ni16.4Al3.7. The remelted layer exhibits a structural rearrangement immediately prior to the primary crystallization event, possibly associated with the formation of a quasicrystalline phase.
10.1557-JMR.2008.0335	-1		Influence of casting temperature on the thermal stability of Cu- and Zr-based metallic glasses (MGs) was analyzed based on the monomer-cluster structural model using the Johnson-Mehl-Avrami (JMA) equation. The result indicates that increasing the casting temperature can enhance the thermal stability of MGs. It is suggested that it be attributed to the decrease in the amount of the local ordering clusters induced by the elevating casting temperature. The prediction is confirmed by continuous heatinc, transformation diagrams constructed for the Cu- and Zr-amorphous samples obtained under different casting temperatures.
10.1557-JMR.2009.0069	11	glass; bulk; metallic; bulk metallic; gfa; bmg; glassy; metallic glass; ability; bulk metallic glass; amorphous; addition; crystallization; mm; glass-forming	Bulk metallic glasses (BMGs) with high thermal stability and good corrosion resistance were synthesized in the (Cu0.6Hf0.25Ti0.15)(100-x-y)NiyNbx system by copper mold casting. The addition of Ni element causes an extension of a supercooled liquid region (Delta T-x = T-x-T-g) from 60 K for Cu60Hf25Ti15 to 70 K for (Cu0.6Hf0.25Ti0.15)(95)Ni-5. The simultaneous addition of Ni and Nb to the alloy is effective in improving synergistically the corrosion resistance in 1 N HCl, 3 mass% NaCl, and 1 N H2SO4 + 0.01 N NaCl solutions. The highly protective Hf-, Ti-, and Nb-enriched surface film is formed by the rapid initial preferential dissolution of Cu and Ni, which is responsible for the high corrosion resistance of the alloys in the solutions examined.
10.1557-JMR.2010.0062	-1		Using the microindentation test, the stress-assisted-electrochemical corrosion of Cu46.25Zr45.25Al7.5Er1 bulk metallic glass (BMG) was studied in a 10 wt% NaCl electrolyte. The microindentation was performed in an indentation load range of 500 to 4000 mN to create shear bands over the deformation zone. Electric current of various densities was passed through the indented BMGs to evaluate the effect of shear bands and localized deformation on the electrochemical corrosion of the BMGs. Surface pits always initiated from the shear-banding zone and the contact edges between the indenter and the BMGs, and the size of the corroded zone grew with the increase in the polarization time, the indentation load, and the current density. Wormlike amorphous whiskers were formed over the corroded zone, and the density of the wormlike whiskers increased with the current density and polarization time.
10.1557-jmr.2013.290	1	shape; memory; shape memory; damping; martensite; martensitic; damping capacity; transformation; capacity; strain; superelasticity; temperature; cu-al-mn; shape memory effect; effect	Suction casting (SC) and centrifugal casting (CC) are two common special casting processes. The influences of SC and CC on the microstructural development of Cu-10Al-4Fe-4Ni aluminum bronzes were investigated with continuous cooling method. The results indicate that alpha, beta', K-II, and K-III phases are observed in the quasicast microstructure via the SC process with the precipitation sequence of K-II -> alpha -> K-III. Additionally, K-I and K-IV are observed in the quasicast microstructure via the CC process with the precipitation sequence of alpha + K-I -> K-II -> K-IV -> K-III. Phase initial precipitation temperatures of the CC process are higher than that of the SC process, especially for alpha phase. As the quenching temperature decreases, the hardness of both alloys shows a rapid decline trend and finally reaches a steady state. It is found that the eutectoid decomposition (beta -> alpha + K-III) barely affects the hardness of the alloys.
10.1557-jmr.2013.86	-1		The relationship between electric current direction and recrystallization rate as well as the resulting texture induced by electric current pulses (ECPs) was investigated in a Cu-Zn alloy. To distinguish the effect of electric current direction on recrystallization rate, the same input energy was exerted upon the samples to eliminate the effect of Joule heating induced by ECPs. Results showed that the recrystallization-related nucleation rate could be greatly enhanced when the electric current was dispositioned at an angle to the rolling direction. The main mechanism for the different nucleation rates might be ascribed to the different driving forces for recrystallization induced by ECPs when there was an angle between the electric current direction and the rolling direction. By all reckoning, it was expected that the ECP treatment would provide a promising approach for controlling the nucleation rate by changing the exerted electric current direction.
10.1557-jmr.2014.132	11	glass; bulk; metallic; bulk metallic; gfa; bmg; glassy; metallic glass; ability; bulk metallic glass; amorphous; addition; crystallization; mm; glass-forming	(Cu0.47Zr0.45Al0.08)(100-x)Dy-x (x = 0, 1, 2, 3, 4; at%) metallic glasses with greatly enhanced glass-forming ability (GFA) and plasticity were synthesized based on microalloying technique. The structure, thermal stability, and elastic properties of the BMG samples were studied by x-ray diffraction (XRD), differential scanning calorimetry (DSC), and ultrasonic measurements, respectively. With addition of minor dysprosium (Dy), fully metallic glassy rods with diameters exceeding 20 mm could be successfully fabricated by copper mold casting. In addition, the Cu-Zr-Al-Dy BMGs exhibit good mechanical properties under a compressive deformation mode, i.e., high yield strength of 1735-1906 MPa, Young's modulus of 85-100 GPa, and distinct plastic strain up to 4.02%. The strength and plasticity show remarkable correlations with glass transition temperature and Poisson's ratio, respectively. The role of minor Dy addition in enhancement in GFA and mechanical property of the Cu-rich BMGs is also discussed.
10.1557-jmr.2015.119	7	irradiation; shear; grain; ta; deformation; size; radiation; voids; nanocrystalline; simulations; similar; void; temperature; irradiated; boundaries	Cu90Ag10 alloys were subjected to severe plastic deformation at temperatures ranging from 25 to 400 degrees C and strain rates ranging from 0.1 to 6.25 s(-1) using high-pressure torsion. The deformed samples were characterized by x-ray diffraction, transmission electron microscopy, and atom-probe tomography. A dynamic competition between shear-induced mixing and thermally activated decomposition led to the self-organization of the Cu-Ag system at length scales varying from a few atomic distances at room temperature to approximate to 50 nm at 400 degrees C. Steady-state microstructural length scales were minimally affected by varying the strain rate, although at 400 degrees C, the grain morphology did depend on strain-rate. Our results show that diffusion below 300 degrees C is dominated by nonequilibrium vacancies, and by comparison with previous Kinetic Monte Carlo simulations [D. Schwen et al, J. Mater. Res. 28, 2687-2693 (2013)], their concentration could be obtained.
10.1557-jmr.2015.143	-1		The Cu-Cr system alloys with different Ti contents were prepared and processed by deformation and heat treatment. The microstructures, mechanical, and electrical properties were investigated under as-cast and aged conditions. The results indicate that the Cr precipitates present a dispersed distribution and exhibit a face-centered cubic (fcc) structure rather than equilibrium body-centered cubic (bcc) structure in the initial stage of aging. A certain amount of Ti atoms dissolves in matrix due to the large solid solubility, while the remaining atoms segregate around the interface of the Cr precipitates to form a sandwich structure. Improvement of mechanical properties is achieved with Ti addition and the increasing rolling reduction, which can be ascribed to multiple mechanisms. In addition, Ti has a negative effect on the electrical conductivity, while deformation has a slight effect on conductivity.
10.1557-jmr.2015.226	-1		The effect of current direction (CD) on the microstructural evolution and mechanical properties of a Cu-Zn binary phase (alpha + beta) alloy during the primary process of phase transformation induced by electric current pulses (ECP) treatment was investigated. To clarify the effect of CD, the samples were prepared with different angles between the CD and rolling direction (RD) from 0 degrees to 90 degrees. Results showed that not only the microstructural evolution but also the corresponding mechanical properties all had a saddle point in the sample with the angle 45 degrees. Analyzed from the mechanical properties, it could be found that the anisotropic of the materials becomes stronger due to the application of ECP. An important finding is that by changing the angles between the CD and the RD, a novel and effective approach to control the phase transformation process could be provided.
10.1557-jmr.2016.404	17	wear; composites; coating; friction; composite; coatings; surface; tribological; properties; wear resistance; resistance; powder; sliding; matrix; wear rate	Cu-FeS composites without lead were prepared by power metallurgy process. The friction and wear properties were examined on a block-on-ring testing machine under dry sliding conditions with and without oil immersion. Results showed that both the frictional coefficient and the wear volumes decreased with increased FeS content in the composite under dry sliding conditions. In the condition of dry friction without oil immersion, the FeS solid lubricating film formed and played a role of antifriction and adhesion resistance. Under the dry friction condition with oil immersion, the lubricant oil stored in the porous FeS layer precipitated to the surface to form the oil film, which could work together to achieve a liquid-solid synergistic lubrication with the FeS transfer film. The lubrication performance of the collaborative lubrication reaction is better than that of the solid transfer film. With the increase of FeS, the collaborative lubrication became more obvious.
10.1557-jmr.2017.145	-1		With an aim to develop novel Cu-Zn alloys with high mechanical properties, in this study, Ni and Si elements were added to Cu-10Zn and Cu-20Zn alloys, and four kinds of Cu-Zn alloys were synthesized through gravity casting. The effect of the addition of Ni and Si on the microstructure and mechanical properties has been systematically investigated. Results revealed that the addition of Ni and Si not only refined the microstructure but also played significant roles to improve the mechanical properties of Cu-Zn alloys; delta-Ni2Si precipitates were formed in the Cu-20Zn-1.5Ni-0.34Si alloy, which obeyed a crystal orientation relationship of (001)(Cu)parallel to(001)(delta) and [110](Cu)parallel to[100](delta). As compared with the Cu-20Zn alloy, the tensile strength of the studied Cu-20Zn-1.5Ni-0.34Si alloy was increased from 373.2 MPa to 776.4 MPa, and the yield strength increased from 242.1 MPa to 718.4 MPa. Operative strengthening mechanisms in the Cu-20Zn-1.5Ni-0.34Si alloy with different thermal-mechanical treatment states will be discussed in detail with the aim to draw a new strategy to develop high strength brass alloys.
10.1557-jmr.2017.17	15	aging; strength; conductivity; electrical conductivity; electrical; mpa; treatment; strengthening; degrees; cu-; cold; precipitation; tensile strength; tensile; iacs	A Cu-0.13Cr-0.074Ag (wt%) alloy has been synthesized by the nonvacuum melting and casting followed by thermal-mechanical treatment, and microstructure and mechanical properties have been tailored to make a trade-off between the strength and the electrical conductivity. Results illuminated that the designed alloy has a tensile strength of 473 MPa, a hardness of 140 HV, a yield strength of 446 MPa, an elongation of 10.5%, and an electrical conductivity of 94.5% IACS. Microstructure observations of the samples aged at 480 degrees C showed that: an fcc structure Cr-phase with a cube-on-cube orientation relationship with the Cu matrix was formed as aged for 15 min, while an ordered bcc structure Cr phase with B2 structure formed as aged for 2 h . The 3DAP results revealed that the Cr was formed to be precipitates and the Ag was formed as solutes distributing evenly in matrix. The high electrical conductivity was ascribed to the Cr element precipitated from the Cu matrix, Ag dissolved in the Cu matrix had little effect on the scattering of Cu electron.
10.1557-jmr.2017.213	-1		Nanoscale metallic material composites consisting of bilayer and trilayer systems of two and three different metallic alternating layers show significant gains in hardness over monolithic single phase films. One of the main applications of these composites can be as protective coatings to technical components to increase their lifespan acting as a mechanical barrier to the carriers of permanent deformation. In this work, we study the strength of bilayer structures made of alternating layers of niobium (Nb) and copper-nickel (Cu-Ni) alloys. The effect of the layer size and composition on strength and hardening as well as the effect of the metal-alloy interface on the dislocation motion is investigated. The simulations reveal a close relationship between the atomic composition of the alloy and the hardening of the film. The results are also compared with experimental findings on nanopillars made of similar structures, and strong similarities are revealed and discussed.
10.1557-jmr.2017.246	-1		A systematic analysis of the correlation between the valence electrons and the transformation temperatures of Ti-Ni-based shape memory alloys has been carried out by Zarinjad and Liu. They have shown that the valence electron theory can be successfully applied to estimate these temperatures, although the mechanisms of the temperature shift during alloying remains not completely understood. Other important shape memory alloy systems with technological importance are the Cu-Al based, which deserve a thorough analysis concerning the composition influence on the transformation temperatures and the valence electron theory. In this paper, the valence electron concentration, valence electron density (VED), enthalpy of reaction, and crystallographic compatibility were analyzed to understand the mechanisms, which control the transformation temperatures of Cu-Al-based alloys. It was observed that the larger the VED, the more energy is used in the transformation. The same tendency is present when the crystallographic compatibility is smaller. These results show that the valence electron theory based on the VED plays an important role in the prediction of the temperature transformation and the energies involved in the reaction.
10.1557-jmr.2017.56	-1		The effects of minor Cu (0-0.29 wt%) and Mg (0-0.1 wt%) additions on the microstructure, electrical conductivity, mechanical, and creep properties of 8xxx aluminum conductor alloys were studied. The microstructure evolution was investigated using an optical microscope and the electron backscattered diffraction technique. The creep property was characterized by the primary creep strain and the minimum creep rate during creep deformation. The results demonstrated that additions of minor Cu and Mg reasonably improved the ultimate tensile strength but slightly reduced electrical conductivity. The addition of Cu remarkably decreased the primary creep strain but had a negligible effect on the minimum creep rate, leading to a beneficial effect on the short-term creep resistance but no advantage to the creep resistance under the long-term creep process. The minor addition of Mg greatly reduces both the primary creep strain and minimum creep rate, resulting in a significant and effective improvement in the creep resistance.
10.1557-jmr.2018.183	0	solidification; phase; magnetic; magnetic field; undercooling; field; liquid; separation; peritectic; immiscible; cu-; dendrite; phase separation; microstructure; primary	Monosized spherical Cu-20% Sn (wt%) alloy particles with diameter ranging from 70.6 to 334.0 m were prepared by the pulsated orifice ejection method (termed POEM). Fully dense without pores and bulk inclusions, the cross-sectional micrographs of the spherical alloy particles indicate an even distribution of Cu and Sn. These spherical Cu-Sn alloy particles exhibit a good spherical shape and a narrow size distribution, suggesting that the liquid Cu-Sn alloy can completely break the balance between the surface tension and the liquid static pressure in the crucible micropores and accurately control the volume of the droplets. Furthermore, the cooling rate of spherical Cu-20% Sn alloy particles is estimated by a Newton's cooling model. The cooling rate of the Cu-20% Sn alloy particle decreases gradually with the particle diameter increasing. Smaller particles have higher cooling rates and when the particle diameter is less than 70 m, the cooling rate of particles can reach more than 3.3 x 10(4) K/s. The secondary dendrite arm spacing has strong dependence on particle diameter which increases gradually with the increase of particle diameter. The results demonstrate that POEM is an effective route for fabrication of high-quality monosized Cu-20% Sn alloy particles.
10.1557-jmr.2018.185	-1		A supersaturated single-phase Cu-26 at% Co alloy was produced by high-pressure torsion deformation, leading to a nanocrystalline microstructure with a grain size smaller than 100 nm. The nonequilibrium solid solution decomposed during subsequent isothermal annealing. In situ high-energy X-ray diffraction was used to map changes linked to the separating phases, and the development of a nanoscale Cu-Co composite structure was observed. To gain further information about the relationship of the microstructure and the mechanical properties after phase separation, uniaxial tensile tests were conducted on as-deformed and isothermally annealed samples. Based on the in situ diffraction data, different isothermal annealing temperatures were chosen. Miniaturized tensile specimens with a round cross section were tested, and an image-based data evaluation method enabled the evaluation of true stress-strain curves and strain hardening behavior. The main results are as follows: all microstructural states showed high strength and ductility, which was achieved by a combination of strain-hardening and strain-rate hardening.
10.1557-jmr.2018.22	-1		Axisymmetric reverse extrusion experiments were conducted on annealed Cu rod specimens to form cup-shaped structures with sidewall thicknesses ranging from similar to 400 mu m down to similar to 25 mu m. Changes in Cu grain morphology, size, and texture were examined through scanning electron microscopy and electron backscatter diffraction (EBSD). Pole figure and orientation distribution function analysis of EBSD data showed the same texture components in the present small-scale metal forming experiments as those observed in macroscale sheet metal rolling. The plastic deformation became inhomogeneous as the characteristic dimension for extrusion decreased to similar to 25 mu m, such that the deformation process involved a small number of Cu grains. Extrusion force-punch displacement curves were measured as a function of extruded cup sidewall thickness and compared to outputs of a continuum plasticity finite element analysis in corresponding geometries. The present work illustrates materials characteristics in small-scale metal forming and suggests directions of future work for bringing improved correspondence between experimentation and modeling.
10.1557-jmr.2018.253	-1		A Cu-3%Ti (wt%) alloy was processed by multiaxial forging (MAF) at cryogenic temperature up to 3 cycles, imposing a total strain of 1.6. Microstructure and mechanical properties of the unprocessed and cryo-forged samples were analyzed. X-ray diffraction results showed deviation in peak broadening and peak intensity of the cryo-forged samples in comparison to that of unprocessed, which are due to texture modification caused by grain refinement during the MAF process. Microstructural analysis showed reduction in grain size from 80 gm in the as-received condition to 250 nm after 3 cycles. Electron backscatter diffraction results indicated the transformation of high angle grain boundaries to low angle grain boundaries in all 3 cycles when compared to the as-received condition. Reduction in ductility was observed after 1 cycle, but with an increase in the number of cycles, both strength and ductility increased. After 3 cycles, ultimate tensile strength and hardness reached 1126 MPa and 427 HV as compared to 528 MPa and 224 HV for the as-received condition. Fractography analysis showed decrement in dimple size after 1 cycle, in comparison to that of the as-received condition. However, it kept on increasing for higher number of cycles.
10.1557-jmr.2019.57	17	wear; composites; coating; friction; composite; coatings; surface; tribological; properties; wear resistance; resistance; powder; sliding; matrix; wear rate	The FeMnCoCr high-entropy alloy/TiC/CaF2 self-lubricating coatings were successfully prepared on a Cu-Zr-Cr alloy for continuous casting mold by laser cladding for wear-resistance. The intriguing finding was that the laser-cladded FeMnCoCr is mainly composed of face-centered cubic and hexagonal close-packed solid solution phases. During the cladding process, the FeMnCoCr/TiC or the FeMnCoCr/TiC/CaF2 mixed sufficiently with Cu matrix, while FeMnCoCr exhibited a spherical shape owing to being insoluble in Cu. The average hardness of the FeMnCoCr/TiC/CaF2 self-lubricating high-entropy alloy (HEA) coatings was twice that of the pure FeMnCoCr HEA coating. By addition of TiC, the friction coefficient and wear rate were decreased from 0.35 and 3.68 x 10(-15) mm(3)/m to 0.27 and 3.06 x 10(-15) mm(3)/m, respectively. When CaF2 was added, the friction coefficients and wear rate were decreased to 0.16 and 2.16 x 10(-15) mm(3)/m, respectively, which was 54% lower than the pure FeMnCoCr HEA coating. The main wear mechanism of the FeMnCoCr coating is abrasive wear while that of the FeMnCoCr/TiC coating is abrasive and adhesion wear. But adhesion wear is dominant for the FeMnCoCr/TiC/CaF2 coating.
10.1557-jmr.2020.100	-1		Elevated temperature co-sputtering of immiscible elements results in a variety of self-organized morphologies due to phase separation. Cu-Ta is used as a model system to understand the evolution of phase-separated microstructural morphologies by co-sputtering thin films with nominal 50-50 at% composition at four temperatures: 25, 400, 600, and 800 degrees C. Scanning/transmission electron microscopy of the film cross sections showed the microstructure morphology varied from nanocrystalline Cu-Ta at 25 degrees C to a wavy ribbon-like structure at 400 degrees C, to Cu-rich agglomerates surrounded by Ta-rich veins at 600 and 800 degrees C. In the agglomerate-vein morphology, microstructural features were present on two length scales, from a few nanometers to a few tens of nanometers, thus making the structures hierarchical. On the nanoscale, the Cu-rich agglomerates contained Ta precipitates, whereas the Ta-rich veins had embedded Cu nanocrystals. The various microstructures can be attributed to the highly disparate constituent element interdiffusion at the deposition temperatures with the Cu having orders of magnitude higher mobility than Ta at the deposition temperatures. This study of processing-microstructure relationship will be useful in guiding the design of hierarchical multiphase microstructures in binary or multicomponent thin films with tailored mechanical properties.
10.1557-jmr.2020.198	15	aging; strength; conductivity; electrical conductivity; electrical; mpa; treatment; strengthening; degrees; cu-; cold; precipitation; tensile strength; tensile; iacs	In this paper, CuCr-Zr alloys prepared by vacuum melting with adding La and Ni elementswere heat-treated and aged, followed by plastic deformation using low-energy cyclic impact tests, to simultaneously improve their mechanical and electrical properties. Results showed that the grain size of the casted Cu-Cr-Zr alloys was significantly reduced after the solid-solution aging and plastic deformation process. There were a lot of dispersed Cr and Cu5Zr precipitates formed in the alloys, and the numbers of dislocations were significantly increased. Accordingly, the hardness was increased from 78 to 232 HV, and the tensile strength was increased from 225 to 691 MPa. Electrical conductivity has not been significantly affected after these processes. The enhancement of overall performance is mainly attributed to the combined effects of solid-solution hardening, fine grain hardening, and precipitation/dislocation strengthening.
10.1557-jmr.2020.226	-1		Grain boundary (GB) motions, such as migration, sliding and rotation, have been shown to play a vital role in the mechanical performance of polycrystalline metals. Despite extensive efforts have been made on the pure polycrystalline metals, few attentions have been paid to those in alloys. In this work, taking conventional nanoscale Cu-Al binary alloy system as an example, we intend to shed some light on understanding its GB motions under shear loading by means of molecular dynamics (MD) simulations. It is found that either shear-coupled GB migration or sliding motion can be observed, depending on GB tilt angles, temperatures and Al solute concentrations. By systematical MD simulations, the Al concentration required for transition between shear-coupled migration and sliding is found to decrease with increasing tilt angles (theta <= 50(degrees)) at fixed temperature, whereas it switches to the opposite trend for larger tilt angles. Furthermore, the GBs migrate much slower comparing with those in pure Cu, which shows the drag effects of the Al solutes in the alloy form. Moreover, the critical stress during shear loading shows a linear dependence on 2/3 power of the temperature.
10.1557-jmr.2020.258	-1		In the alloy materials, their mechanical properties mightly rely on the compositions and concentrations of chemical elements. Therefore, looking for the optimum elemental concentration and composition is still a critical issue to design high-performance alloy materials. Traditional alloy designing method via trial and error or domain experts' experiences is barely possible to solve the issue. Here, we propose a composition-oriented method combined machine learning to design the Cu-Zn alloys with the high strengths, high ductility, and low friction coefficient. The method of separate training for each attribute label is used to study the effects of elemental concentrations on the mechanical properties of Cu-Zn alloys. Moreover, the elemental concentrations of new Cu-Zn alloys with the good mechanical properties are predicted by machine learning. The current results reveal the vital importance of the composition-oriented design method via machine learning for the development of high-performance alloys in a broad range of elemental compositions.
10.1557-mrc.2019.59	-1		The software package ESPEI has been developed for efficient evaluation of thermodynamic model parameters within the CALPHAD method. ESPEI uses a linear fitting strategy to parameterize Gibbs energy functions of single phases based on their thermochemical data and refines the model parameters using phase equilibrium data through Bayesian parameter estimation within a Markov Chain Monte Carlo machine learning approach . In this paper, the methodologies employed in ESPEI are discussed in detail and demonstrated for the Cu-Mg system down to 0 K using unary descriptions based on segmented regression. The model parameter uncertainties are quantified and propagated to the Gibbs energy functions.
10.1557-s43577-022-00323-4	-1		Nanoporous copper (np-Cu) films that feature fine ligament length scales and high surface area are prepared using an all-electrochemical approach . The two-step routine involves initially the electrodeposition of CuxZn(100-x) precursor alloy films with controlled thickness and composition from a pyrophosphate bath . This is followed by a selective oxidative removal or dealloying of Zn that leads to a surface area increase (by up to 22 times per one mu m thickness of the precursor alloy). In this article, we present a systematic investigation of the impact of three factors on the as-synthesized np-Cu structure: (1) dealloying bath composition, (2) atomic composition (at%) of precursor alloy, and (3) addition of Ni. Our results show that varying the dealloying bath composition allows for tunable ligament and pore sizes that are due to the anion-induced (ClO4-, SO42-, or Cl-) modified surface diffusivity of Cu. The increase in surface area is also proportionally scalable by modifying the Cu content (12-42 at%) in the precursor alloy. Thus, np-Cu films with porosity length scales in the range of 20-33 nm were obtained. A further np-Cu length scale refinement down to 10-12 nm was achieved after dealloying of a ternary Cu-Zn-Ni(3%) alloy. Overall, the strict parameter control yields a wide range of nano-scaled np-Cu films with specific surface characteristics, which may be suitable for various applications including microelectronic packaging, sensing, and catalysis.
10.1557-s43578-021-00284-5	6	grain; deformation; strain; strength; dislocation; cu-; tensile; size; ecap; grain size; sfe; ductility; hardening; high; stress	The effect of solute atoms on microstructural evolution and grain refinement during equal channel angular pressing (ECAP) was investigated using Cu-Mn alloys where the change of stacking fault energy (SFE) is very small regardless of Mn concentration up to 12 at%. Solute Mn significantly affected the accumulation of dislocations with a resulting decrease in grain size. Cu-10at%Mn formed rare deformation twins and a final grain size of 71 nm. This final grain size is comparable to that of Cu-9at%Al which has comparatively low SFE. The microstructures of Cu-Mn alloys continually developed with persistent strain hardening up to eight passes, whereas that of pure Cu saturated in smaller strain. This strong effect of solute Mn for suppressing dynamic recovery, and associated persistent strain hardening and grain refinement may result from high planarity of dislocation glide, in addition to the solute effect stemming from elastic interaction between solute and matrix. Graphic abstract
10.1557-s43578-021-00444-7	3	sma; shape; shape memory; memory; smas; superelastic; bars; damping; cu-al-mn; mechanical; bending; applications; numerical; sma bars; material	Cu-based shape memory alloys belong to one important class of functional alloys, presenting shape memory effect and superelasticity due to their reversible martensitic transformation. Although they have been extensively studied since the middle of the last century, there are still many challenges to be solved. In the last decades, these alloys were extensively studied regarding new compositions, processing routes, phase transformation, mechanical and functional properties. Aspects of the thermoelastic phase transformation have been described using thermodynamic and thermo-mechanical studies, while the role of metallurgical features (such as grain size and morphology, ordering, precipitates and second phases) have been described mainly by phenomenological approach . In this sense this review discusses the advances in the general fundamentals of Cu-based shape memory alloys, the recent developments in processing routes, compositions, and applications in the last years.
10.1557-s43578-022-00487-4	-1		The direct metal deposition (DMD) additive manufacturing process produces high cooling rates within a small melt pool and can lead to high amounts of solute trapping. These high cooling rates limit diffusion and lead to the formation of non-equilibrium phases. In this work, we utilize a numerical model to calculate the degree of solute trapping, defined as non-equilibrium partitioning. A theoretical case with overall composition fixed to 50Cu-50Fe at%. was performed to observe the influence of increasing solidification rates. We then simulate DMD of equimolar Cu-Fe powder printed on mild steel substrate and the calculated non-equilibrium phase compositions were consistent with experimental observations reported earlier on this alloy composition. For a single deposited track, cooling rates are high enough to yield significant solute trapping. The degree of solute trapping is highest near the free surface and has a gradient that correlates with the cooling rate gradient.
10.1557-s43578-022-00854-1	-1		Synthesis of Cu3SbS4 nanocrystalline materials by mechanical alloying using elemental powders as the precursors is studied in this work. The elemental powders are mechanically alloyed for 40 h and the crystal structure is explored by X-Ray diffraction. The X-ray diffraction pattern demonstrates homogenous product with excellent crystalline Cu3SbS4 nanocrystals was synthesized using mechanical alloying. By employing high-resolution transmission electron microscopy to examine the powder particle size, distribution, and shape, the wurtzite structure of the Cu3SbS4 nanocrystals was discovered. The optical properties are determined by UV-Visible spectroscopy. HRTEM images reveal the size of the capped Cu3SbS4 nanocrystals ranges from 1.5 to 6.5 nm, with absorption peaks located between 889 and 987 nm. Detailed analysis of the nano-crystalline material revealed that the defects created during the mechanically alloyed method hinder its applications in photovoltaic applications, and additional processing should also be developed as economically produced Cu3SbS4 nanocrystalline materials have the potential for energy applications.
10.1557-s43578-023-01210-7	-1		(87-x)Cu-13Al-xFe (x: 1, 2, 3, 4, 5 wt%) alloys were prepared by arc melting deposition process. Results showed that with the increase of Fe content, the memory recovery ratio of (87-x)Cu-13Al-xFe alloy showed a three-phase change of decrease-increase-decrease under 4% pre-strain. The memory recovery ratio of the 4Fe alloy reached 100%. The analysis shows that a Fe-rich kappa phase is formed when the Fe content exceeds its solubility in the Cu-Al alloy. The kappa-phase not only shifts the eutectoid point of the alloy to the right and refines the grain size but also has a pinning effect. This effect flattens the grain boundaries of the alloy, elongates the grains, and increases the order degree of the martensite, thereby improving its shape memory properties. However, when the Fe content is too high, the alloy will enter a sub-eutectic state, leading to the coexistence of two-phase martensite and reducing the shape memory properties of the alloy.
10.1557-s43578-024-01508-0	-1		This additive manufacturing (AM) work is focused on developing a new combination of aluminium-copper (Al-Cu) alloys using direct ink writing (DIW) methods for automotive, aerospace, and electrical industry components. The combination of adding Cu in Al at various percentages ranging from 20 to 80% is applied in this work to evaluate the synergistic properties. The microstructure, mechanical properties, and chemical composition of the thermally post-processed parts were studied by Vickers microhardness, X-ray diffraction (XRD), optical microscope, and scanning electron microscope (SEM) with energy dispersive X-ray analysis (EDX). The investigation reveals that the mechanical property, microstructure, and chemical composition depend upon the physical inclusions of Cu with Al. Our results show that 40% Cu composition possesses crucial traits like the hardness of 656 HV due to the formation of AlCu intermetallics without any unwanted oxides.
10.1557-s43579-023-00353-2	-1		Positron annihilation lifetime spectroscopy was used to investigate the microstructure of commercial Cu-Cr-Zr and Ni-W ultrafine-grained alloys processed by severe plastic deformation namely equal channel angular pressing, accumulative roll bonding and groove pressing and annealing at 600, 900 and 1000?. All the lifetime spectra bear the same trends and were a sum of three exponential decay components. The dominant vacancy/dislocations component lifetime changed considerably and dropped after high temperature annealing. Positron lifetime spectroscopy results correlated well with microhardness measurements. The results suggest the presence of three stages in Cu-Cr-Zr and Ni-W industrial alloys which were attributed to dislocations storage through severe plastic deformation, recovery-recrystallization and grain growth .
10.1557-s43579-023-00361-2	-1		Cu-12.5Al-3Mn-xNi (x: 0,1,2,3 wt%) alloys were prepared by wire arc melting deposition. Results showed that the change of Ni contents had little effect on the shape memory properties under 4% pre-strain, but the shape recovery rate of 1Ni alloy maintained at 100%, and its stability for repeated bending recovery is excellent when the pre-strain increases to 6% and 8%. However, the shape recovery rate of 0Ni alloy decreases linearly when the pre-strain similarly changes. Results indicated that an appropriate amount of Ni can fill the vacancies in the additive manufacturing Cu-Al-Mn alloy, and improve its shape memory properties under large pre-strains.
10.1557-s43579-025-00850-6	14	strength; properties; conductivity; electrical; mechanical; cu-; grain; mpa; electrical conductivity; aging; precipitation; phase; mechanical properties; tensile; phases	This study investigates the temperature-dependent nanomechanical behavior of pure Cu and Cu-8wt% Al (Cu8Al) using high-temperature nanoindentation. Cu8Al consistently showed lower penetration depths due to solid solution strengthening. Both materials exhibited thermal softening, with reduced hardness and modulus at higher temperatures. Cu8Al displayed a higher elastic recovery index, indicating greater elastic energy storage from dislocation interactions. The findings highlight the role of solute atoms and thermal activation in governing nanoscale mechanical responses under thermal stress.
10.1590-1516-1439.027715	-1		Two consolidated copper samples were prepared by consolidation of a gas atomized powder using two different routes of spark plasma sintering (SPS), respectively. The first route was direct SPS of copper powder at 800 degrees C for 10 minutes, and the second route was compacting copper powder by die-pressing to produce a powder compact followed by SPS of the powder compact at 800 degrees C for 10 minutes. The microstructures and tensile mechanical properties and the fracture surfaces of specimens have been studied. It was found that the level of consolidation of the sample made using Route 1 was higher than that of the sample made using Route 2, as reflected by the relatively higher strength and better ductility of the first sample than those of the second sample. The lower consolidation level of the second sample was depicted by the higher volume fraction of cavities in the fracture surfaces of specimens which were formed by separation of the powder particles at the weakly bonded interparticle boundaries. The grain sizes of the first sample were larger than those of the second sample. The reasons for the differences in the levels of consolidation and gain sizes associated with two SPS routes are discussed.
10.1590-1516-1439.032415	16	wear; composite; composites; powders; milling; particles; powder; wt; sliding; friction; hardness; matrix; mechanical; surface; properties	The microstructural evolution of Cu-10at%C nanocomposite powder during high energy mechanical milling (HEMM) of Cu/graphite powder mixture was studied. It was found that the efficiency of milling in refining the microstructure of the copper matrix was very high with the presence of graphite in the Cu/graphite powder mixture. The average grain size of the Cu matrix reaches its minimum value of about 30 nm just after milling for 6 h, and the graphite particles were refined down to about 10 similar to 20 nm after milling for 24 h . It envisaged that the refining of graphite particles down to 10 nm would be accompanied by formation of nanograins of copper matrix, and it appears that high energy mechanical milling can greatly enhance the solubility of carbon in copper though it is very hard to determine the exact solubility.
10.1590-1516-1439.277114	-1		Consolidation of amorphous powders, which take advantage of the supercooled liquid region, is an alternative way to overcome the size limitation in marginal metallic glasses. Cu36Ti34Zr22Ni8 based amorphous powders were obtained during high energy ball-milling. The analyses revealed that amorphous structures of powders and ribbons are quite different and this led to a different thermal behavior being the powders more thermally stable than the ribbons. Extrusion was initially proposed as a consolidation process; however, the decrease in viscosity in remainder amorphous matrix was not sufficient for that process, but certainly sufficient for sintering the sample during hot consolidation. An amorphous/nanocrystalline microstructure known for enhancing the mechanical properties of their fully amorphous counterparts was obtained. Evaluation of mechanical properties by microhardness revealed the relatively high hardness of HV 768. From these results, consolidation by sintering seems a promising route to produce bulk metallic glasses nanocomposites.
10.1590-1980-5373-MR-2016-0962	2	corrosion; surface; film; electrochemical; films; spectroscopy; layer; current; solution; potential; resistance; composition; x-ray; ions; showed	This work proposes the production of Cu-Sn alloy coatings with anticorrosive properties, using an environmentally non-aggressive bath . The coatings were electrodeposited on carbon steel substrate AISI 1020 using an electrolyte containing CuCl2 and SnCl2, and sodium tartrate as the complexant agent. The produced coatings were characterized by scanning electron microscopy (SEM), X-ray diffraction (XRD), inductively coupled plasma optical emission spectrometry (ICPOES) and electrochemical impedance spectroscopy (EIS). The film showing the highest corrosion resistance was obtained using j = 100 Am-2. This coating was composed by 95.18 % m/m Cu and 4.83 % m/m Sn, and presented a uniform surface, without defects and small grain sizes. These characteristics probably contributed to the formation of Cu-Sn protective film onto steel substrate from a tartrate bath .
10.1590-1980-5373-MR-2017-0153	4	transformation; martensite; martensitic; phase; shape; beta; memory; shape memory; temperature; temperatures; martensitic transformation; gamma; transformation temperatures; effect; thermal	Two Cu-Zn-Al alloys with variable content of Zn (25 and 30 wt%) and constant Al content (4 wt%) prepared by induction melting of pure metals and hot rolled into strips of 0.5 mm thickness were thermally processed by using three different heat treatments: direct quenching, step-quenching and upquenching with boiling water and room temperature water as the quenchants. The effects of composition and different methods of heat treatment on the microstructure and transformation temperatures of the investigated Cu-Zn-Al alloys were investigated using SEM-EDS and DSC techniques.
10.1590-1980-5373-MR-2017-1044	-1		Cu-based shape memory alloys (SMAs) present some advantages as higher transformation temperatures, lower costs and are easier to process than traditional Ti-based SMAs but they also show some disadvantages as low ductility and higher tendency for intergranular cracking. Several studies have sought for a way to improve the mechanical properties of these alloys and microstructural refinement has been frequently used. It can be obtained by laser remelting treatments. The aim of the present work was to investigate the influence of the laser surface remelting on the microstructure of a Cu-11.85Al-3.2Ni-3Mn (wt%) SMA. Plates were remelted using three different laser scanning speeds, i.e. 100, 300 and 500 mm/s. The remelted regions showed a T-shape morphology with a mean thickness of 52, 29 and 23 mu m and an average grain size of 30, 29 and 23 mu m for plates remelted using scanning speed of 100, 300 and 500 mm/s, respectively. In the plates remelted with 100 and 300 mm/s some pores were found at the root of the keyhole due to the keyhole instability. We find that the instability of keyholes becomes more pronounced for lower scanning speeds. It was not observed any preferential orientation introduced by the laser treatment.
10.1590-1980-5373-MR-2017-1059	-1		A comparative investigation on the microstructural morphologies and hardness values of Cu-35 wt% Zn and Cu-30 wt% Zn with 1.5 wt% Al content is provided. Distinctive specimens by using traditional investment casting were produced. Specimens withdrawn from distinct locations along the castings were thermally and microstructural analyzed. Thermally and chemically induced microstructural modifications affecting the microstructure and hardness are discussed. It is found that components ( specimens) located at different positions along of the pattern tree casting have distinctive hardness values. This is associated with Cu segregation and cooling rate. It is also found that solidified piece under a cooling rate similar to 0.12 K/s has hardness 20% higher than the specimen solidified under 0.07 K/s. Duplex brass with Widmanstatten structure constitutes the resulting microstructure array. This seems to be associated with Al content, while both Zn and Al contents are associated with cooling rate as responsible parameter to induce Widmanstatten structure formation.
10.1590-1980-5373-MR-2017-1139	-1		In this paper, a composition of known high glass-forming ability, Cu42Zr42Al8Ag8 and a novel Cu42Zr42Al8Ag4Sn4, were produced by suction-casting. After rapid solidification of both alloys, X-ray diffraction patterns along with crystallite size estimation by Scherrer equation and scanning electron microscopy images revealed a refined microstructure, composed mainly by AlCu2Zr, CuZr2 and Cu10Zr7 phases. Transmission electron microscopy indicated the presence of small crystalline precipitates in the Cu42Zr42Al8Ag4Sn4 suction-casted sample. Polarization curves showed a higher passivation current in the Sn containing sample, suggesting a decrease in corrosion resistance.
10.1590-1980-5373-mr-2018-0121	-1		This work analyzed experimental and numerically the growth kinetics of beta ' precipitation of a Cu(4)wt% Ti alloy after aging at 400, 500 and 600 degrees C for times from 0.0166 h to 200 h . Results indicated that the precipitation process is almost controlled by nucleation and growth during aging at 400 degrees C, originating a slow growth kinetics of precipitation. In contrast, the coarsening of precipitates dominates the precipitation process during aging at 500 and 600 degrees C. The interfacial energy of interface between the a matrix phase and beta ' precipitates was determined to be about 0.1135, 0.0980 and 0.0725 Jm(-2) for aging at 400, 500 and 600 degrees C, respectively. These values suggest a coherent interface which is in agreement with the flat faces of beta ' cuboid precipitates. Calculated Time-Temperature-Precipitation diagram for the beta ' precipitation indicated good agreement with experimental results. Precipitation hardening was higher for the slower growth kinetics of precipitation.
10.1590-1980-5373-MR-2018-0272	2	corrosion; surface; film; electrochemical; films; spectroscopy; layer; current; solution; potential; resistance; composition; x-ray; ions; showed	Cu-Co alloys were electrodeposited on steel substrates from alkaline sodium tartrate electrolyte using direct and single pulsed current (DC and SPC, respectively). The electrodeposition bath was composed by 0.02 mol L-1 of CuSO4 center dot 5H(2)O, 0.10 mol L-1 of CoSO4 center dot 7H(2)O and 0.50 mol L-1 of Na2C4H4O6 center dot 4H(2)O. Using both kind of deposition processes, it was verified that the applied current density (j) affected the cathodic current efficiency (E-f), the copper and cobalt contents in the coatings (wt. % Cu and wt. % Co, respectively), the morphology and the anticorrosive performance of the coatings (based on the transfer charge resistance, (R-ct) values). Comparing the results obtained for DC and SPC coatings, those produced by single pulsed current improved the E-f values and decreased the grain sizes. Concerning the conditions used in this work, the coating produced under the conditions of Experiment 4', using j(m) = 40 A m(-2 )and SPC mode, presented 15.9 wt. % Co, the most compact morphology, the smallest grain size and the highest R-ct value after 24 h of exposure in the saline medium.
10.1590-1980-5373-mr-2019-0078	-1		This work highlights the relationship between the preparation, crystallization behavior, microstructures, and mechanical properties of Cu-based bulk metallic glasses (BMGs) and their composites (BMGCs). (Cu47Zr43Al8)(97).5Y1.5Nb in-situ BMGCs were prepared using isothermal annealing, and the experimental results indicate tunable mechanical properties of the alloys by processing parameter manipulation. The crystallinity of (Cu47Zr45Al8)(97.5)Y1.5Nb BMGCs increases with extended annealing temperature and time, while their phase transition with rising temperature follows Am (amorphous state) -> Am + Cu10Zr7 -> Am + Cu10Zr7 + AlCu2Zr + Al2Zr. Precipitation strengthening during annealing above 720 K (447 degrees C) can enhance the alloy microhardness remarkably and achieve an optimum of 712 HV by annealing at 800 K (527 degrees C) for 60 min. TEM results show that Cu10Zr7 with sizes of 12 similar to 15 nm precipitates out upon crystallization and thereby accounts for the superior compressive property. The alloy exhibits a fracture strength up to 2080 IVfPa after annealing at 680 K (407 degrees C) for 30 min. Morphological observation of the fracture surface reveals a transition of fracture characteristics from the typical amorphous ductile manner to a brittle manner with further annealing. The investigation provides novel thoughts of BMGs processing for further performance improvement.
10.1590-1980-5373-MR-2019-0086	4	transformation; martensite; martensitic; phase; shape; beta; memory; shape memory; temperature; temperatures; martensitic transformation; gamma; transformation temperatures; effect; thermal	The understanding of the stabilization mechanism of martensite used to obtain alloys with high hysteresis and the possibility of recovering this martensite (residual strain) by heating at temperatures higher than A(s) and A(f) have been fundamental for application in bonding devices. One of the possibilities to enhance residual strain is through mechanical cycling. This work evaluated the influence of number of cycles and the effect of precipitation of Nb-rich particles as mechanisms to increase residual strain in superelastic Cu-Al-Be-Nb alloys. The results showed that the presence of Nb-rich precipitates was not a predominant factor for the enhancement of residual strain. In addition, mechanical cycling has proved to be an efficient mechanism for raising residual strain, and consequently increasing the amount of martensite retained. However, the gain of residual strain is accompanied by an increase of plastic deformation.
10.1590-1980-5373-MR-2019-0259	-1		The microstructure and mechanical properties of cast materials are strongly dependent on the thermal history during solidification process. The global casting industry has faced major challenges, i.e., customers increasingly demand completely finished cast parts as well as complexity of casting alloys are rising. Therefore, the previous knowledge the solidification conditions effects on the as-cast ingot microstructure and mechanical properties resulting is very useful in the casting industry in order to improve the casting quality. In this present paper, the thermal parameters effects on the microstructure, microhardness and microsegregation of a Cu- 20 wt% Sn alloy under transient heat flow conditions were experimentally investigated. The experimental observations indicate that the tertiary dendritic arm spacing (lambda(3)), microsegregation and microhardness are affected by the thermal parameters (solidification speed and cooling rate). Solidification speed (S-S) associated with increasing cooling rate (R-C) are found to contribute to the decreasing tertiary dendritic arm spacing (lambda(3)). However, cooling rates from 11.36 degrees C/s to 0.65 degrees C/s were not found to affect significantly the microhardness along the ingot length . The solute concentration (Sn) in solid region were calculated by Scheil and Clyne-Kurz equation, and used in the predictions of microsegregation profiles. The results calculated by equations, have shown deviations from the experimental data. It is well known that it is very difficult to calculate these concentration profiles using the equilibrium partition coefficient, since frequently castings solidify under non-equilibrium conditions and the solidification process is known as non-equilibrium solidification. For this reason, effect of solidification speed (S-S) was considered into equations through effective partition coefficient (k(ef)) that has been determined for the range of solidification speed experimentally examined between 0.19 and 0.89 mm/s. However, results calculated by Scheil and Clyne-Kurz equation using the effective partition coefficient (k(ef)), yielded discrepancies from the experimental results. Because of its deviations between calculated and experimental data, an experimental equation with effective partition coefficient (k(ef)), is considered in present work, showing an excellent agreement with the experimental data.
10.1590-1980-5373-MR-2019-0542	-1		Shape memory alloys are generally produced by casting processes and are subsequently homogenized. However, to obtain semifinished products on an industrial scale, the ingots from the casting process must be hot worked. In particular, final bar and sheet products can be obtained by hot roiling process. During intense hot work, surface oxidation of the material and microstructural changes may cause modifications to its original thermomechanical properties. In this sense, the present work aimed to study the correlation of the superelastic behavior in a Cu-Al-Be-Cr alloy before and after subjecting it to the hot rolling thermomechanical process. Abnormal grain growth was observed for a hot rolled sample with 30% reduction in initial alloy thickness. This abnormal growth in relation to non-rolled alloy caused an increase in phase transformation temperatures, a reduction in residual strain- a reduction in induction stress and an increase in alloy superelasticity.
10.1590-1980-5373-MR-2021-0173	-1		The high temperature oxidation of Cu-32.02% Zn-2.30%Pb brass was carried in N-2-5wt% O-2 and N-2-12 wt% O-2 atmospheres. The amounts of oxygen in the oxidizing atmospheres and the time of the oxidation affected the oxide morphologies and kinetics of the oxide growth . In the first hour of the oxidation at 650 degrees C, oxide nanowires were noted. The average diameter, length and distance between the observed nanowires were 27 +/- 0.01 nm, 0.20 +/- 0.04 mu m and 0.20 +/- 0.04 mu m respectively for the samples oxidized in N2-5wt% O-2 atmosphere and 102 +/- 23 nm, 0.36 +/- 0.24 mu m and 0.24 +/- 0.08 mu m respectively for the samples oxidized in N-2-12wt% O-2 atmosphere. The EDX and XRD analyses of the nanowires and the oxide granules confirmed ZnO nanowires and a continuous oxide layer of ZnO. The x-ray diffraction confirmed minor presence of PbO. The oxide growth kinetics followed the linear oxide growth model, for the alloy samples that were thermally oxidized in N-2-5 wt% O-2 atmposphere and parabolic growth model for those thermally oxidized in N-2-12 wt% O-2 atmospheres respectively. The values of 6.8 mu m/hour and 23.03 mu m/(hour)(1/2)were determined for growth constant (k), based on the two models respectively.
10.1590-1980-5373-MR-2021-0390	16	wear; composite; composites; powders; milling; particles; powder; wt; sliding; friction; hardness; matrix; mechanical; surface; properties	The present investigation aims to coat the layer with Nickel (Ni) and Copper (Cu)over the surface of strenx 900 steel using semi sintered Cu-10Ni-Crx electrodes(x = 2, 4 & 6 wt. %). Three different proportions of semi sintered electrodes such as, Cu-10Ni-2 weight percentage of Chromium (Cr), Cu-10Ni-4 wt. % Cr,and Cu-10Ni-6 wt. % Cr were prepared by powder metallurgy route. Electric discharge alloying was completed based on L9 orthogonal array and alloyed parameters were optimized using Taguchi method. The alloyed surfaces were characterized using scanning electron microscope and atomic force microscopy. The deposition of formation of intermetallic was studied using X-ray diffractometer. Higher Material Transfer Rate (MTR) was obtained at 9A, 350A and 6% chromium using Cu-10 Ni-Cu electrode. The chromium percentage was the foremost factor on Surface Roughness (SR) (73.71%) and MTR(96.56%). From Taguchi approach, the minimum SR was attained at percentage of chromium of 2%, compaction pressure of 250 Megapascal (MPa) and peak current of 9A. The maximum MTR was achieved at 6 percentage of Cr, compaction pressure of 350 MPa and peak current of 3A. Wear loss for Cu-10 Ni-Cr increases linearly with increase in sliding speed from 2m/s to 4m/s respectively.
10.1590-1980-5373-MR-2022-0041	2	corrosion; surface; film; electrochemical; films; spectroscopy; layer; current; solution; potential; resistance; composition; x-ray; ions; showed	This work reports the production of low-tin Cu-Sn alloy coatings on carbon steel substrates using a bath containing CuCl2, SnCl2, and sodium citrate. In the first part of this study, the coatings were electrodeposited by direct and simple pulse current processes (DC and SPC, respectively). Different current density values were used, while the pulse frequency and duty cycle remained constant. Independent of the current mode used, low-tin Cu-Sn coatings, showing globular surface morphology and Cu6Sn5 as the main compositional phase, were produced. Both the current mode and the applied current density affected the anticorrosive properties of the coatings. The most protective DC and SPC coatings, showing Sn content < 3 wt% and compact morphology, were prepared using j = 80 A m(-2) and j(c) = 167 A m(-2), respectively. High charge transfer resistance values were verified even after immersion for 24 h in 0.5 mol L-1 NaCl solution.
10.1590-1980-5373-MR-2022-0581	5	materials; thermal; heat; properties; material; welding; sintering; fusion; strength; laser; heat sink; thermal conductivity; mechanical; sink; manufacturing	The copper alloy UNS-C27200 is a binary brass, composed of 38wt%Zn, beeing one of the most used in the industry. The union of Cu-Zn alloys by conventional welding by fusion in thin plates presents several challenges. The Friction Stir Welding (FSW) process performs the union of two, or more materials, through a rotating tool that travels throughout the welding region. One the great advantages of FSW is working below the melting point of the material, which reduces the change in the microstructure and properties of the material, when compared to conventional welding processes. Due to the lack of research on FSW process in lap brass joints with thin thicknesses, the present work aims to expand these studies in order to contribute to future research . Eight conditions were evaluated, varying rotation and welding speed. In the best results by visual inspection, analyzes of microstructure, temperature, microhardness and mechanical strength were performed. The better welding results were obtained with & omega;=1050 rpm and & nu;=20 mm/min. There was reduction of approximately 50% between Stir Zone and Base metal. The mechanical strength was affected by the pin hole resulting from the process. The microstructure revealed a homogeneous mixture in the stir zone and no defects were detected.
10.1590-1980-5373-MR-2023-0076	2	corrosion; surface; film; electrochemical; films; spectroscopy; layer; current; solution; potential; resistance; composition; x-ray; ions; showed	This work compares the anticorrosive properties of DC electrodeposited CuCoNi, CuCo, and CuNi alloy coatings in a NaCl 0.5 mol L-1 solution. The results showed that j and the bath composition influenced the chemical, morphological, and electrochemical characteristics of the alloy coatings. Among all the studied coatings, the CuCo, CuNi, and CuCoNi ones produced at j = 10 A m-2, j = 60 A m-2, and j = 25 A m-2, respectively, showed the best anticorrosive performances in the saline medium, exhibiting charge transfer resistances (Rtc) higher than 2000 & omega; cm2 and an electrical double layer capacitances (Cdl) lower than 8 X10-4 F cm-2. These results agree with the compact morphologies and smaller grain sizes presented by these coatings. Therefore, the anticorrosive properties of the coatings cannot be related only to the less noble metal(s) contents in the alloy but also to their morphologies.
10.1590-1980-5373-MR-2025-0149	2	corrosion; surface; film; electrochemical; films; spectroscopy; layer; current; solution; potential; resistance; composition; x-ray; ions; showed	In the present work, we explored the production of Cu-Sn alloy coatings with anti-corrosive properties using simple pulse current (SPC) electrodeposition. The effects of the pulse parameters pulse frequency (F) and duty cycle (gamma)-on the surface characteristics of the coatings produced at a constant average current density value were evaluated to verify the corrosion protection performance of these coating systems in a saline medium. Coatings with small grains, high Sn content, a single Cu6Sn5 phase microstructure, and reduced porosity were obtained by increasing F and gamma, improving the cathodic current efficiency and charge transfer resistance in the NaCl 3.5%w/v. The most protective coating, produced at F = 1500 Hz and gamma = 50%, showed a Sn content near that of commercial bronze and a charge-transfer resistance of 4097 Omega cm2, which is approximately 2.5 times higher than the resistance of a protective alloy obtained by DC electrodeposition.
10.1590-S1516-14392010000400006	-1		The major concern of the design for manufacturability is to accomplish the require deformation without failure of work material. The degree of deformation that can be achieved in a particular metal forming process without creating condition is termed as workability. The present investigation pertains to study the cold workability behaviour of Cu-7%Al-1.8%Si sintered preforms. Cold upsetting of these preforms with various aspect ratios were carried out and the working behaviour of the preforms at various stress state conditions was computed. The analysis measured for different components such as stress formability index and obtained density during secondary deformation as a function of induced strain. Similarly various computed stress ratio parameters with induced strain.
10.1590-S1516-14392014005000089	-1		Free dealloying of Cu-Hf-Al metallic glasses in HCl electrolytes are studied in this paper. The results show that the electrolyte concentration and dealloying time strongly influence the type of dealloying products. A superficial dealloying happens in diluted HCl electrolytes while a complete dealloying occurs in concentrated HCl electrolytes. The results present that Cu2O microparticles with regular morphology can be tailored on glassy surfaces in 0.05 M HCl solution by controlling the dealloying time. Furthermore, the designable products of nanoporous Cu, Cu2O nanoplates and CuO microwires can be fabricated in 1.2 M HCl electrolyte with the dealloying time. Due to a big difference of examined Cu-Hf-Al alloys in the electrolyte concentration and dealloying time, one or mixed dealloying products (Cu, Cu2O and CuO), which depend on the progress of relative chemical reactions and the different dealloying route, will finally be produced.
10.1631-jzus.A1700261	2	corrosion; surface; film; electrochemical; films; spectroscopy; layer; current; solution; potential; resistance; composition; x-ray; ions; showed	Cu(In,Ga)Se-2 (CIGS) precursor films were deposited on Mo/glass by electrodeposition, and then annealed in Se vapor. The annealing temperature ranged from 450 A degrees C to 580 A degrees C, and two heating rates were selected. The results showed that the crystalline quality of the CIGS films and formation of the Cu-Se compound could be strongly influenced by the selenization temperature and heating rate. Raman spectroscopy and X-ray diffraction (XRD) analysis showed that when the selenization temperature was increased from 450 A degrees C to 550 A degrees C, the amount of binary CuSe phase decreased and the amount of Cu2Se increased. After annealing at 580 A degrees C, a minimum amount of Cu2-x Se compounds was obtained and the degree of CIGS film crystallinity was higher than in other samples. The relationship between the properties of the film and the heating rate was studied. XRD and Raman spectra showed a decrease in the Cu2-x Se phase with increasing heating rate. Scanning electron microscopy (SEM) and XRD showed a remarkable increase in the grain size of CIGS during rapid heating.
10.1680-jemmr.16.00022	-1		Copper (Cu)-aluminum oxide (Al2O3) composite sheets were prepared by internal oxidation of copper-aluminum (Al) alloy sheets with different aluminum contents. For the same internal oxidation temperature and time, the microstructures and properties of the copper-aluminum oxide composite sheets were compared. In order to prepare a densified copper-aluminum oxide bulk composite, the remelting solidification method of copper-aluminum oxide composite sheets was tried. The results show that with increasing aluminum content, the internal grains become coarser and the depth of the internal oxidation layer becomes narrower for the same internal oxidation time. The hardness of internal oxidation layer gradually decreases from the surface to the inner layers. For the same internal oxidation time, the higher the aluminum content, the higher the hardness of the internal oxidation layer at the same depth . Aluminum oxide particles inside the molten composite sheets are more likely aggregate and rise during the remelting-solidification process. The preparation of copper-aluminum oxide bulk composites by the internal oxidation-remelting solidification method is infeasible.
10.1680-jemmr.20.00088	16	wear; composite; composites; powders; milling; particles; powder; wt; sliding; friction; hardness; matrix; mechanical; surface; properties	This experimental and statistical study focuses on investigation of the effects of machining parameters on surface roughness (SR) and material removal rate (MRR) in wire electrical discharge machining (WEDM) of hard copper (Cu) alloy. Experimental design was carried out using the L18 (2(1) x 3(2)) orthogonal array according to the Taguchi method. The process parameters considered were wire type, pulse time and duration between two pulses. Copper-coated wire and zinc (Zn)-coated wires were used as cutting tools. Analysis of the signal-to-noise (S/N) ratio was utilized to investigate the effects of process parameters on the responses. Analysis of variance was employed to determine the percent contributions and significance levels of process parameters on responses. Analysis of the surface integrity and characteristics of the machined specimens was observed using scanning electron microscopy, and energydispersive X-ray spectroscopy analysis was employed. This study may be used as a reference to investigate SR and MRR in WEDM of hard copper alloy.
10.17222-mit.2020.166	-1		In this paper we investigated the phase-transformation dynamics of the Cu-3Ti-3Ni-0.5Si alloy by applying the Avrami method to phase-transformation dynamics and electrical conductivity based on the relationship between the electrical conductivity and the volume fraction of precipitates in the Cu-3Ti-3Ni-0.5Si alloy. The results corroborated well with the experimental data. The microstructure and precipitated phases were characterized by scanning electron microscopy (SEM) and transmission electron microscopy (TEM). The analysis of the selected-area electron-diffraction patterns indicated that the precipitates formed in the matrix of the Cu-3Ti-3Ni-0.5Si alloy during aging, correspond to the Ni3Ti, Ni3Si, and Ni2Si phases. According to the values of formation enthalpy and cohesive energy determined by first-principle calculations, the formation of the Ni2Si phase is more favorable compared to the Ni3Si and Ni3Ti phases, and the Ni3Ti exhibits improved structural stability compared to the Ni2Si and Ni3Si phases.
10.17222-mit.2023.782	2	corrosion; surface; film; electrochemical; films; spectroscopy; layer; current; solution; potential; resistance; composition; x-ray; ions; showed	Passive films formed on a Cu-Ni alloy in various concentrations of alkaline environment were investigated by potentiodynamic polarization, electrochemical impedance spectroscopy (EIS), X-ray photoelectron spectroscopy and the Mott-Schottky approach . The wide passivation range of the copper-nickel alloy was tested in alkaline solutions of three concentrations. The oxide film on the specimen has a p-type semiconductor property, while the flat band potential (EFB) decreased with increasing solution concentration. The film resistance of the passive films increased with increasing solution concentration. The pAassive films showed a duplex structure, including an inner layer of oxide (Cu2O, NiO) and an outer layer of hydroxide (Cu(OH)2, Ni(OH)2).
10.20964-2017.04.27	2	corrosion; surface; film; electrochemical; films; spectroscopy; layer; current; solution; potential; resistance; composition; x-ray; ions; showed	In this study, the effect of seasonal variability on the marine environment in the corrosion of Cu and Cu-Alloys was analyzed in situ with respect to exposure time. The possible changes in the mechanism of degradation, considering the physicochemical parameters of seawater were studied. An electrochemical study was carried out with three metallic materials industrially used (copper, bronze and brass) for 10 months of continuous exposure in seawater surrounding the San Juan de Ulua Fortress in Veracruz port, Mexico. Electrochemical impedance spectroscopy (EIS) was the electrochemical technique used. Additionally, a characterization of the metal surface with scanning electron microscopy (SEM) and X-ray diffraction (XRD) was carried out. All materials showed good corrosion resistances; however, copper showed higher resistance which took their best values in the last months of exposure presenting a layer of products of Cu2O. Additionally, some silicates and sulfates were detected. Pitting and localized corrosion type was observed.
10.20964-2017.06.78	2	corrosion; surface; film; electrochemical; films; spectroscopy; layer; current; solution; potential; resistance; composition; x-ray; ions; showed	Cu-W thin films were electrodeposited on indium tin oxide (ITO) glass substrates in an aqueous solution using a rectangular pulse current technique in a range of frequency from 0.2 MHz to 1 MHz. The W concentration in the Cu-W thin film measured with energy dispersive X-ray spectroscopy (EDX) was dependent on an amplitude and frequency of the rectangular pulse current. The maximum W concentration in the Cu-W thin film was 9 wt. %. X-ray diffraction (XRD) revealed that the Cu-W thin film had crystallographic planes parallel to the ITO glass substrate such as (111), (200), (220), and (311) planes. Surface images of the Cu-W thin film observed with scanning electron microscope (SEM) showed an aggregation of an island called a nano cauliflower. These experimental results indicate that the Cu-W thin film was an alloy comprising copper and tungsten, and that tungsten was electrodeposited in the aqueous solution free of the iron-group element.
10.20964-2017.07.63	2	corrosion; surface; film; electrochemical; films; spectroscopy; layer; current; solution; potential; resistance; composition; x-ray; ions; showed	Aluminium in a Cu-Mo-Al thin film generated on an indium tin oxide (ITO) glass substrate in an aqueous solution by a rectangular pulse current technique in a range of frequency from 0.2 to 1.5 MHz was demonstrated. The aluminium concentration in the Cu-Mo-Al thin film measured with energy dispersive X-ray spectroscopy (EDX) was observed only in the vicinity of a resonant frequency. Several resonant frequencies existed at a certain interval in the range of the frequency. The resonant frequency spacing between the neighboring resonant frequencies became about 0.2 MHz. These experimental results are discussed from a viewpoint of energy level transition between the Fermi energy of electron in an electrode and a quantized rotational energy of a cluster of a trivalent aluminium ion and divalent molybdate ion. The maximum aluminium concentration in the Cu-Mo-Al thin film was about 6 wt. %. X-ray diffraction (XRD) analysis showed that (111), (200), (220), and (311) planes well consistent with those of polycrystalline copper existed parallel to the ITO glass. The Cu-Mo-Al thin film is found to be an alloy comprising Cu, Mo, and Al. In addition, surface images of the Cu-Mo-Al thin film observed with scanning electron microscope (SEM) showed an aggregation of nano cauliflowers.
10.20964-2018.04.26	2	corrosion; surface; film; electrochemical; films; spectroscopy; layer; current; solution; potential; resistance; composition; x-ray; ions; showed	Cu-Zr thin films electrodeposited on indium tin oxide glasses from aqueous solutions containing potassium sodium tartrate tetrahydrate using rectangular pulse current over a frequency range of 0.5-1.4 MHz were investigated. Resonant frequencies at which the Zr content in the Cu-Zr thin films was maximum were identified using energy dispersive X-ray spectroscopy. A resonant frequency interval between the neighboring resonant frequencies was 0.26 MHz on average. The resonant frequencies and resonant frequency interval were explained in terms of an energy level transition between the Fermi energy level of electron in the indium tin oxide and quantized rotational energy level of a complex ion comprising Zr and tartaric ions in the aqueous solution. X-ray diffraction analysis confirmed that the Cu-Zr thin film was an alloy composed of Cu and Zr. Surface images of the Cu-Zr thin film observed using scanning electron microscopy indicated an aggregation of cauliflower-like islands consisting of nano-scale grains.
10.20964-2018.07.10	2	corrosion; surface; film; electrochemical; films; spectroscopy; layer; current; solution; potential; resistance; composition; x-ray; ions; showed	Copper was exposed for a total period of six months in an urban atmosphere, Shenyang site of China. The corrosion data of the exposed copper were collected for monthly intervals. The products and the corrosion amounts accumulated on the exposed copper have been investigated by mass loss, scanning electron microscopy, X-ray diffraction and coulometric reduction. The corrosion loss calculated from the reduction charges were compared with mass loss from the weight technique. The primary corrosion products found on field-exposed samples were copper oxides. For shorter exposure, such as no more than one month, the corrosion products were composed of Cu2O and CuO. For more than two month exposure, the chemical components were mainly Cu2O and CuO, and Cu-2(OH)(3)Cl and Cu2S were also observed on the surface of the field exposed copper. The corrosion mechnisms of copper at Shenyang site are proposed as well.
10.20964-2018.12.11	2	corrosion; surface; film; electrochemical; films; spectroscopy; layer; current; solution; potential; resistance; composition; x-ray; ions; showed	The corrosion charateristic of Cu-10Ni-Fe-x alloys (x=0.84, 1.26, 1.76) in 3.5 % NaCl solution was investigated by using electrochemical impedance spectroscopy, potentiodynamic polarization curve, X-ray Diffraction and X-ray photoelectron spectroscopy. The results showed that the order of corrosion resistance is Cu-10.52Ni-1.26Fe>Cu-10.44Ni-0.84Fe>Cu-10.48Ni-1.76Fe. Fe exists in the form of FeOOH and FeO in the product films, whilst Ni exists in the form of NiO, Ni(OH)(2), and metallic Ni in the product films. FeOOH promotes the enrichment of the Ni content and the formation of NiO. The product film of Cu-10.52Ni-1.26Fe with the best corrosion resistance contained the highest content of FeOOH. In addition, the mechanism of FeOOH on the corrosion resistance has been discussed.
10.20964-2019.12.32	2	corrosion; surface; film; electrochemical; films; spectroscopy; layer; current; solution; potential; resistance; composition; x-ray; ions; showed	In this work, the anodic dissolution properties of Cu-Zn-Ni alloy scraps in 45 g L-1 CuSO4 solutions have been analyzed. The analysis methods employed were potentiodynamic polarization techniques, electrochemical impedance spectroscopy and electron probe microscopic analysis. In a certain range, the anodic dissolution of the Cu-Zn-Ni alloy scraps in CuSO4 solutions increased with the H2SO4 concentration and temperature. The overall dissolution of the Cu-Zn-Ni alloy scraps were found to be under anodic control; further, the anodic dissolution process was under diffusion control deduced from the activation energy of the anode dissolution process being 14.6 kJ mo1(-1). After heat treating the alloy scraps, the Cu-Zn-Ni alloy scraps were found to be more susceptible to dissolution due to the increase of the size of the grains and the decrease of the particle size uniformity.
10.20964-2020.03.97	2	corrosion; surface; film; electrochemical; films; spectroscopy; layer; current; solution; potential; resistance; composition; x-ray; ions; showed	The corrosion behaviour of brass (Cu/30Zn) alloy in 4M LiBr solution was investigated by the cyclic potentiodynamic polarization and current-time measurements. The work was complemented by the use of scanning electron microscopy (SEM) and the energy dispersive X-ray (EDX) analysis techniques. Cyclic potentiodynamic polarization indicated that the current of the Cu/30Zn alloy increases linearly and a plateau area was appearing with increasing the applied potential. The oxide film formed on the surface of the alloy was not passive or protective and the dissolution of Cu/30Zn alloy occurred via general corrosion. The pitting attack was not recognized as there was no hysteresis loop observed at all conditions. The results obtained from the SEM micrographs and EDX profile analyses confirmed that the ratio of Cu to Zn on the surface was found higher than that detected from matrix of the alloy. The mechanism of corrosion of the Cu/30Zn alloy via the dezincification of the surface was found to occur by a simultaneous dissolution.
10.20964-2020.08.33	2	corrosion; surface; film; electrochemical; films; spectroscopy; layer; current; solution; potential; resistance; composition; x-ray; ions; showed	The atmospheric corrosion behavior of benzotriazole treated Cu-based coins in synthetic sweat was investigated. Electrochemical impedance spectroscopy showed that the protective effect of BTA on copper coins gradually failed in synthetic sweat with the prolongation of immersion time. The copper coin coated with BTA protective film had a faster corrosion rate under cyclic wet-dry test of regularly wetting synthetic sweat. From the composition analysis of protective film and corrosion products, BTA not only complexed with Cu2+ Cu2+, but also reacted with Zn2+/Ni2+. The thickness of the patina layer can reach to 100 mu m after 240h accelerated experiment, and the corrosion products were simple in composition, mainly basic Cu-2(OH)(3)Cl and oxides of Ni and Zn. However, BTA had little protective effect on copper in synthetic sweat, and didn't affect the composition of final corrosion products.
10.20964-2021.02.35	2	corrosion; surface; film; electrochemical; films; spectroscopy; layer; current; solution; potential; resistance; composition; x-ray; ions; showed	By studying the corrosion behavior of high strength C71500 Cu-Ni alloy pipe at the inlet and outlet of heat exchanger in simulated high polluted seawater at different temperatures, which could provide theoretical basis for improving the service life of the alloy. The corrosion mechanism of the alloy was determined by electrochemical techniques such as potentiodynamic polarization curve, electrochemical impedance spectroscopy (EIS) as well as cyclic voltammetry curve (CV) and the morphology and composition of corrosion products were analyzed by immersion test, SEM, EDS, XPS and XRD. The results show that the alloy exhibits activation polarization at all test conditions, the higher the solution temperature, the greater the corrosion rate. When the temperature reaches 35 degrees C, the average corrosion rate of the alloy is stable at about 0.0121 mm/a. In the initial stage of corrosion, diffusion process could be observed. Corrosion products have a certain protective effect, the diffusion process disappears and the EIS shows only capacitive reactance arc with the prolong the immersion time. The addition of high concentration of Na2S promotes the formation of Cu2S and the redox process, thus accelerating the corrosion process. At relatively low temperature, the dominant process is Ni dissolution, while the content of Cu and S dissolving increase at high temperature. The thickness and compactness of corrosion products increase with the increasing temperature, which promotes to reach a relative stable corrosion rate. More sulfide species corrosion product could be detected at the low temperature, and the dissolution of copper is the main corrosion process at high temperature.
10.22190-FUME201215042H	16	wear; composite; composites; powders; milling; particles; powder; wt; sliding; friction; hardness; matrix; mechanical; surface; properties	Electrical Discharge Machining (EDM) is one of the most popular non -conventional machining processes that are being used in many high precision manufacturing industries. To increase the EDM performance, a hybrid technique, namely, powder mixed electrical discharge machining (PMEDM) is generally used for getting more precise requirements. In this study, an experimental investigation is carried out in order to explore the machining performance of the PMEDM process on Ti-6Al-4V alloy using copper (Cu) powder in the EDM oil dielectric. Taguchi's L18 orthogonal array design has been utilized for design of experiments and the analysis of variance (ANOVA) has been performed with the help of Minitab-19 software. The optimal parametric setting of Cu powder mixed EDM has been found utilizing the Taguchi -Grey Relational Analysis (GRA) integrated approach and also validation of optimal parametric setting is done through experimentation. It is a novel approach for machining Ti-6Al-4V alloy by this PMEDM technique in which the surface quality has been improved significantly with the addition of suitable amount of Cu powder into the dielectric medium.
10.2298-JMMB140121007R	16	wear; composite; composites; powders; milling; particles; powder; wt; sliding; friction; hardness; matrix; mechanical; surface; properties	Our work deals with the problem of producing a complex metal-ceramic composite using the processes of internal oxidation (IO) and severe plastic deformation. For this purpose, Cu-Al alloy with 0.4wt% of Al was used. IO of sample serves in the first step of the processing as a means for attaining a fine dispersion of nanosized oxide particles in the metal matrix. Production technology continues with repeated application of severe plastic deformation (SPD) of the resulting metal-matrix composite to produce the bulk nanoscaled structural material. SPD was carried out with equal channel angular pressing (ECAP), which allowed that the material could be subjected to an intense plastic strain through simple shear. Microstructural characteristics of one phase and multiphase material was studied on internally oxidized Cu with 0.4wt% of Al sample composed of one phase copper-aluminum solid solution in the core and fine dispersed oxide particles in the same matrix in the mantle region. In this manner AFM, X-ray diffraction and Raman spectroscopy were used. Local structures in plastically deformed samples reflect presence of Cu, CuO, Cu2O, Cu4O3 or Al2O3 structural characteristics, depending on type of sample.
10.2298-JMMB150515009Z	12	thermodynamic; ternary; phase; data; experimental; equilibria; phase equilibria; liquid; binary; experimental data; calculated; phases; literature; model; calphad	13 ternary Cu-Mg-Si alloys were prepared by means of the powder metallurgy method. Phase equilibria at 500 and 700 degrees C of the Cu-Mg-Si system were determined using X-ray diffraction analysis (XRD). The existence of 3 ternary compounds in this system was verified: CuMgSi_Sigma (Cu16Mg6Si7), Tau (Cu3Mg2Si), and Laves ((Cu0.8Si0.2)(Mg0.88Cu0.12)). A thermodynamic modeling for the Cu-Mg-Si system was then conducted on the basis of the experimental data obtained in this work and those critically reviewed from the literature. The complex phase relationship between Laves phase and other phases has been successfully modeled in this work. Comparisons between the calculated and the measured phase diagrams show that most of the experimental data can be reproduced by the presently obtained thermodynamic parameters.
10.2298-JMMB170515034S	-1		The ternary Cu-Al-Sn phase diagram is the base for several important types of alloys, with relevant industrial interest and applications. The knowledge of the melting/solidification alloys characteristics are determinant for their preparation and properties control. However, there is a lack of experimental information on the ternary phase diagram, at high temperature. In this work, several alloys, with high copper content and additions of Al, up to 10%, and Sn, up to 14% (in wt%), were studied by thermal analysis and by isothermal phase equilibria determination. The alloys liquidus and solidus lines and the binary alpha + beta phase field, at 800 degrees C, are presented for the studied range of compositions.
10.2298-JMMB170809039H	12	thermodynamic; ternary; phase; data; experimental; equilibria; phase equilibria; liquid; binary; experimental data; calculated; phases; literature; model; calphad	Four Cu-rich alloys from the ternary Cu-Al-Mn system were prepared in the electric-arc furnace and casted in cylindrical moulds with dimensions: phi = 8 mm and length 12 mm. Microstructural investigations of the prepared samples were performed by using optical microscopy (OM) and scanning electron microscopy, equipped by energy dispersive spectroscopy (SEM-EDS). Assignation of crystalline phases was confirmed by XRD analysis. Phase transition temperatures were determined using simultaneous thermal analyzer STA DSC/TG. Phase equilibria calculation of the ternary Cu-Al-Mn system was performed using optimized thermodynamic parameters from literature. Microstructure and phase transitions of the prepared as-cast alloys were investigated and experimental results were compared with the results of thermodynamic calculations.
10.2298-JMMB180209009J	12	thermodynamic; ternary; phase; data; experimental; equilibria; phase equilibria; liquid; binary; experimental data; calculated; phases; literature; model; calphad	Phase equilibria at 900 degrees C and the liquidus projection in the Ni-rich corner of the Cu-Ni-Ti ternary system were investigated by X-ray diffraction (XRD), scanning electron microscopy (SEM), electron probe microanalysis (EPMA) and dfferential scanning calorimetry (DSC) on the annealed and as-cast alloys. For the isothermal section at 900 degrees C, the high-temperature ternary compound (tau 5) reported in the literature was not observed but the corresponding low-temperature compound (tau(6)) was identified to be stable at this temperature. For the liquidus projection, the primary phase .1 4 was experimentally determined for the first time, and the related solidification paths were identified through the experimental data on the as-cast alloys. One solid-state invariant reaction, NiTi + tau(4) -> tau(1) + Ni3Ti at 1098.3 degrees C and two ternary eutectic reactions, L -> tau(1) + tau(4) + NiTi at 1126 degrees C and L -> tau(1) + tau(6) + fcc(Cu,Ni) at 1069.5 degrees C were detected. Scheil reaction scheme was also presented accordingly. All obtained experimental results will provide reliable information for further thermodynamic optimization of the Cu-Ni-Ti ternary system.
10.2298-JMMB180503025J	16	wear; composite; composites; powders; milling; particles; powder; wt; sliding; friction; hardness; matrix; mechanical; surface; properties	Novel ultrafine grain composites of Cu matrix reinforced with 2-50 wt. % of Ti48Cu39.5Ni10Co2.5 and Ti48Cu39.5Zr10Co2.5 (at. %) amorphous-nanocrystalline alloy particles have been fabricated by powder metallurgy. The composites showed a homogeneous structure. The characterization of composites was performed by optical and scanning electron microscopy (SEM), X-ray powder diffraction (XRD), micro- and macrohardness, as well as density measurements. After hot pressing the crystallite size of Cu was smaller than 200 nm and nanocrystalline phases of reinforcing powder were 5-35 nm. Densities of 97-76 % relative to calculated values of consolidated composites were obtained, depending on the reinforcing weight fraction. Additionally, the mechanical properties and electrical resistivity of composites have been investigated. The results reveal that the 0.2% offset compressive yield strength of composites increases by two and five times, with respect to pure Cu matrix, for the composites reinforced with 2 and 50 wt. % of reinforcing particles, respectively. Electrical resistivity increases continuously, with higher values after 30 wt. % of addition. Changes in mechanical and electrical properties were produced by the increase of amorphous-nanocrystalline additive.
10.2298-JMMB181128020M	-1		Generalised stacking fault energies of copper alloys have been calculated using density functional theory. Stacking fault energy of copper alloys is correlated with the d-electrons number of transition metal alloying element. The tendency to twiningis also modified by the presence of alloying element in the deformation plane. The results suggest that Cu -transition metal alloys with such elements as Cr, Mo, W, Mn, Re are expected to exhibit great work hardening rate due to the tendency to emission of the partial dislocations.
10.2298-JMMB220101015R	-1		Effect of strain energy on corrosion behavior of ultrafine-grained (UFG) copper prepared by severe plastic deformation (SPD) was investigated in terms of microstructural evolution. The SPD processed material showed an ultrafine-grained (UFG) structure after grain refinement for several time processes, which will affect mechanical and corrosion behavior Homogeneity can be obtained efficiently through the pressing process commonly known as simple shear extrusion (SSE), which is one of the SPD techniques. Pure copper was processed by SSE for two, four, eight, and twelve passes. The structure of SSE treated sample was observed by laser microscope and transmission electron microscope as well as X-ray diffraction. The corrosion behavior by potentiodynamic polarization curve was observed in modified Livingstone solution, 1 M NaCl, and sulphuric solution. The structure of SSE processed sample showed that the first pass of the SSE processed sample displayed large deformation by developing the elongated grain and sub-grain structure. By increasing the SSE pass number, the grain shape became equiaxed due to excessive strain. The X-ray broadening related to ultrafine-grained (UFG) structure processed SSE on the copper sample, leading to smaller crystallite size, higher microstrain, and higher dislocation density. More homogeneous passive film was developed on the material with UFG structure appearance. However, the current density in 1 M NaCl was decreased by an increment of pass number due to the dissolution of copper metal. The UFG structure has more boundaries than coarse grain structure, and these phenomena show why Cu dissolve ability influences the current density. The grain boundary behaves as the cathodic site.
10.2298-JSC0701045R	-1		The microstructural and morphological changes of inert gas atomized pre-alloyed Cu-1 wt. % A1 powders subjected to hith-energy milling were studied. The microhardness of hot-pressed compacts was measured as a function of milling time. The thermal stability during exposure at 800 degrees C and the electrical conductivity of compacts were also examined. During the high-energy milling, severe deformation led to refinement of the powder particle grain size (from 550 nm to about 55 nm) and a decrease in the lattice parameter (0.10%), indicating precipitation of aluminium from the copper matrix. The microhardness of compacts obtained from 5. h-milled powders was 2160 MPa. After exposure at 800 degrees C for 5 h, these compacts still exhibited a high microhardness value (1325 MPa), indicating good thermal stability. The increase of microhardness and good thermal stability is attributed to the small grain size (270 and 390 nm before and after high temperature exposure; respectively). The room temperature electrical conductivity of compacts processed from 5 h-milled powder was 79 % IACS.
10.2298-SOS0902185R	16	wear; composite; composites; powders; milling; particles; powder; wt; sliding; friction; hardness; matrix; mechanical; surface; properties	Inert gas atomized prealloyed copper powder containing 2 wt% Al (average particle size approximate to 30 mu m) and a mixture consisting of copper (average particle sizes approximate to 15 mu m and 30 mu m) and 4 wt% of commercial Al2O3 powder particles (average particle size approximate to 0.75 mu m) were milled separately in a high-energy planetary ball mill up to 20 h in air. Milling was performed in order to strengthen the copper matrix by grain size refinement and Al2O3 particles. Milling in air of prealloyed copper powder promoted formation of finely dispersed nano-sized Al2O3 particles by internal oxidation. On the other side, composite powders with commercial micro-sized Al2O3 particles were obtained by mechanical alloying. Following milling, powders were treated in hydrogen at 400 degrees C for 1h in order to eliminate copper oxides formed on their surface during milling. Hot pressing (800 degrees C for 3 h in argon at pressure of 35 MPa) was used for compaction of milled powders. Hot pressed composite compacts processed from 5 and 20 h milled powders were additionally subjected to high temperature exposure (800 degrees C for 1 and 5 h in argon) in order to examine their thermal stability. The results were discussed in terms of the effects of different size of starting powders, the grain size refinement and different size of Al2O3 particles on strengthening, thermal stability and electrical conductivity of copper-based composites.
10.2298-SOS1703225C	16	wear; composite; composites; powders; milling; particles; powder; wt; sliding; friction; hardness; matrix; mechanical; surface; properties	Cu-Ni-MX1480 powder compound were prepared at six different alloy ratios and cold pressed with a pressure of 300 MPa. Then 12 samples were obtained by hot pressing at 700 degrees C with 20 MPa pressure and at 800 degrees C with 30 MPa pressure for 4 minutes in a vacuum atmosphere hot pressing machine. Porosity ratios of samples were calculated by the different between theoretical density and measured density of samples. Effect of porosity on microstructure and mechanical properties were investigated by performing SEM, XRD, hardness measurements and TRS tests. It was observed that as a result of increased hot pressing parameters and increased Cu ratio, porosity ratio was decreased and better mechanical properties achieved.
10.2298-SOS2001015S	16	wear; composite; composites; powders; milling; particles; powder; wt; sliding; friction; hardness; matrix; mechanical; surface; properties	A comparison was made between layer-by-layer laser melting (LM) of two types of feedstock powders: (1) elemental powder blend and (2) mechanically alloyed powder. LM was done by Nd:YAG laser at 1064 nm (max. average power 100 W) in argon ambience. Samples synthesized were Cu-Ti-TiB2 rectangular tracks (20x6x1 mm), and input parameters of the process: powder layer thickness 100-250 mu m, hatch spacing 1 mm, pulse length 4 ms, energy 4 J, pulse repetition rate 20 Hz. Part of the samples was heat-treated in argon at 900 degrees C, 10 h . Structural characterization of the samples was done using light microscope and scanning electron microscope (SEM). Chemical analysis of the as-obtained laser melted samples was done by inductively coupled plasma-atomic emission spectrometry (ICP-AES). It was established that the microstructure of LM samples was comprised of Cu-Ti and Cu-B solid regions, and in situ formed microparticles of primary TiB2. Only after high-temperature thermal treatment has the secondary TiB2 occurred. Tensile tests showed much higher strengthening in heat-treated samples with mechanically alloyed powder as starting material, where the formation of secondary TiB2 nanoparticles was considerable.
10.2298-SOS220421003S	16	wear; composite; composites; powders; milling; particles; powder; wt; sliding; friction; hardness; matrix; mechanical; surface; properties	Copper-zirconium alloys with high conductivity were produced using powder metallurgy. Two-steps manufacturing process, containing mechanical alloying followed by hot pressing, was applied in achieving improved mechanical and physical properties of Cu-Zr alloy. In this paper, the influence of boron on Cu-Zr alloys properties was studied on Cu-1Zr (wt%) and Cu-1.1Zr-0.3B (wt%) systems. Scanning electron microscopy, laser nanoparticle sizer, computed tomography and X-ray diffraction were employed for observation of changes in the microstructure during production steps. More specifically-variations in size of the Cu particles, powder mixtures' structural parameters, and development of CuZr phase in binary alloy, CuZr phase and ZrB2 particles in ternary alloy were observed. It was shown that presence of boron increases dislocation density in ternary alloy over the mechanical alloying time compared to binary alloy. The results presented in this study show higher hardening effect in Cu-Zr-B alloy compared to Cu-Zr alloy, resulting in stable hardness values during thermomechanical treatment. Further, it can be seen that finely dispersed reinforcing ZrB2 particles in copper matrix does not have significant influence on its conductivity. Moreover, both systems Cu-Zr and Cu-Zr-B exhibit better electrical conductivity after thermomechanical treatment as a result of zirconium reduction in solid solution due to its precipitation.
10.2298-SOS230717044D	-1		The aim of this study was to investigate the effect of hexagonal boron nitride (h-BN) addition on copper based alloy system. Varying amounts of h-BN were added to the prepared metal matrix composition as a reinforcing material. The powder mixture was subjected to high-energy mechanical alloying and compacted under 400 N/mm2 and were sintered at 820 degrees C for 2 hours. Following the sintering of the samples characterization procedures were performed after wear and friction testing. The addition of h-BN led to a decrease in dimensional shrinkage after sintering, while the difference between the achieved density and theoretical density increased. XRD results revealed the presence of characteristic peaks attributed to the reinforcement and metallic matrix. The wear tests revealed a significant increase in wear with higher h-BN content under different applied loads. The initial decline in friction coefficient with h-BN addition was followed by an increase as the h-BN content increased.
10.2320-matertrans.43.2908	6	grain; deformation; strain; strength; dislocation; cu-; tensile; size; ecap; grain size; sfe; ductility; hardening; high; stress	Uniform deformation of tempered copper alloy sheets is small, and their bend formability depends largely on the amount of non-uniform deformation. which is complicatedly influenced by other factors in addition to the work-hardening exponent n. In this study, it has been shown that post-uniform elongation in the tensile test can be represented by two parameters, (e(r)-e(u)) and f. The symbol e(f) is the nominal strain at the breakage point, e. the uniform elongation and f the parameter giving the degree of strain localization along the tensile axis. Good correlation between those parameters and bend formability was ascertained by experimental studies on C51900 and some other Cu alloy sheets. The experimental results showed that the introduced two parameters were not independent variables but mutually related. In addition, the nucleation and growth processes of surface wrinkles in bending, which finally led to cracking. were studied metallographically. A lot of micro necks first arose in the vicinity of grain boundaries, and part of them developed into the groove of wrinkles. Spacing between grooves appeared to correspond with the size and distribution of cube-oriented grains.
10.2320-matertrans.44.1225	16	wear; composite; composites; powders; milling; particles; powder; wt; sliding; friction; hardness; matrix; mechanical; surface; properties	Focus of the study has been placed on the effect of graphite content on tribological behavior of a Cu-Fe-C based friction material sliding against FC30 cast iron. Experimental results indicated that, after sintering in air, the densities of Cu-Fe-C specimens decreased, oxygen contents increased, and essentially all original metallic constituents turned into oxides. As graphite content increased, the amounts of Fe2O3, Cu-20 and Cu-Sn decreased, while CuO and FeSn2 contents increased. The friction coefficient profiles of Cu-10%Steel wool-10%Al-10%Al2O3-10%Sn (vol%) material (C0) and Cu-10%Steel wool-10%C-10%Al-10%Al2O3-10%Sn (vol%) material (C10) are almost identical. After sliding for a few minutes, their friction coefficients start to decay. The friction coefficient of Cu-10%Steel wool-20%C-10%Al-10%Al2O3-10%Sn (vol%) material (C20) maintained to be high and stable throughout tests. The mass loss of C20 was larger than that of C0 or C10. The mass loss of FC30 sliding against C20 was smaller than that of FC30 sliding against C0 or C10. While both particulate and film types of debris were observed on each Cu-Fe-C specimen, more particulate debris was observed on CO and C10 than on C20 surface. Chemical analysis of worn surfaces indicated that Fe was dominant on C0 and C10 surfaces, while large amounts of Fe and Cu were detected on the worn surfaces of both C20 and FC30.
10.2320-matertrans.44.2070	-1		Cu-Ge alloy rods were pulled from a hyperperitectic melt at three kinds of pulling rates while the melt temperatures were lowered at controlled rates, respectively by the Czochralski method. The relationship between the pulling rate and the Ge concentration in the alpha phase that solidified first from the melt is approximated by the relation derived from the BPS expression for the effective distribution coefficient. A group of peritectic zeta grains is formed subsequent to the initial growth of alpha crystal in the rods pulled at some rates. Growth of the zeta grains is followed by growth of alpha phase, resulting in the formation of alternating structures of the primary alpha and the peritectic zeta which is accompanied by a simultaneous variation in rod thickness. This appears repeatedly at short intervals along the rod when it is pulled at a high rate. It is concluded that the alternating structures of alpha phase and peritectic zeta grains are formed by a peritectic solidification of Ge-rich melt at the cell boundary that develops on a constitutionally supercooled solid-liquid interface, and that their cessation is due to a decrease in Ge concentration of the liquid at the interface, with subsequent growth of the zeta phase.
10.2320-matertrans.44.2224	11	glass; bulk; metallic; bulk metallic; gfa; bmg; glassy; metallic glass; ability; bulk metallic glass; amorphous; addition; crystallization; mm; glass-forming	The Effect of the Ta addition on the fabrication of the ductile phase reinforced Cu-Zr-Ti bulk metallic glass (BMG) matrix composite was investigated. A composite microstructure consisted of pm-scale Ta-rich solid solution particles distributed in the BMG matrix was successfully obtained by injection casting of the (Cu60Zr30Ti10)(95)Ta-5 alloy into a copper mold. Ta-rich solid solution particles were observed to form first in the liquid melt during solidification, while the remaining melt solidified into the amorphous phase at lower temperature. The monolithic Cu60Zr30Ti10 BMG shows a compressive strength of 2080MPa and a fracture strain of 3.3%, while the (Cu60Zr30Ti10)(95)Ta-5 BMG matrix composite shows compressive strength of 2320MPa and, in particular, a significantly improved plastic strain to failure of about 14.5%. The remarkable ductility improvement in the (Cu60Zr30Ti10)(95)Ta-5 composite could be explained by the presence of the highly ductile Ta-rich particles.
10.2320-matertrans.45.1679	4	transformation; martensite; martensitic; phase; shape; beta; memory; shape memory; temperature; temperatures; martensitic transformation; gamma; transformation temperatures; effect; thermal	Compression tests were performed at different temperatures in an 82.5%Cu-13.5%Al-4.0%Ni (mass %) single crystal, a composition giving the beta'(18R) thermally induced martensitic phase. In all cases, the non-twinned gamma'(2H) martensite was obtained after compression, so, the beta' --> gamma' or beta --> gamma' martensitic transformations were induced, depending of the test temperature. The critical stress vs. temperature, sigma(c)-T, relationship was established for both types of transformations, obtaining a negative slope dsigma(c)/dT (considering compressive stresses as negative) for the austenite-martensite transformation and a small positive slope for the martensite-martensite. The experimental dsigma(c)/dT values were compared with those calculated from the Clausius-Clapeyron type equation and reasonable good agreement between them was obtained. For these calculations, the entropy changes DeltaS(beta'-gamma') and DeltaS(beta-gamma') were directly obtained from the calorimetric runs performed after each mechanical test.
10.2320-matertrans.45.2187	6	grain; deformation; strain; strength; dislocation; cu-; tensile; size; ecap; grain size; sfe; ductility; hardening; high; stress	The properties of multi-functional CuCr and CuCrZr alloys with ultra fine grains (UFG) produced by equal-channel angular pressing (ECAP) have been investigated in dependence of concentration of alloying elements. A special attention is paid to optimization of fatigue performance together with strength, thermal and electric properties after ECAP and subsequent aging. Substantial improvement of fatigue life is evidenced in ECAP-fabricated alloys when compared with conventional tempers.
10.2320-matertrans.45.2851	-1		As a fundamental study to develop a new process for eliminating detrimental elements and for recovering valuable ones from secondary Cu-Fe base alloys with a considerably high content of arsenic, both the phase relations in a miscibility gap of the Cu-Fe-As system saturated with carbon and the distribution of some minor elements of silver, platinum, cobalt, nickel and sulfur between two phases in the miscibility gap were investigated at 1473 K by using a quenching method. The phase separation into copper-rich and iron-rich phases occurred when the Cu-Fe-As system was saturated with carbon. The arsenic content in the copper-rich phase was larger than that in the iron-rich phase, and carbon mostly distributed in the iron-rich phase. Cobalt and nickel distributed preferentially in the iron-rich phase, and platinum and sulfur distributed almost evenly in both phases, while silver mostly in the copper-rich phase. The experimental results for the phase separation and the distribution of the minor elements were discussed on the basis of activity coefficients in the copper-rich and iron-rich phases. By utilizing this phase separation, recovery of valuable silver and copper into the copper-rich phase and elimination of less valuable iron into the iron-rich phase are feasible for treating the secondary Cu-Fe-As base alloys.
10.2320-matertrans.45.2936	11	glass; bulk; metallic; bulk metallic; gfa; bmg; glassy; metallic glass; ability; bulk metallic glass; amorphous; addition; crystallization; mm; glass-forming	A glassy phase containing high volume fractions (V-f) of bcc Ta-based phase was formed in as-cast (Cu0.6Hf0.25Ti0.15)(94)Ta-6 alloy rods with diameters up to 2 mm. Its V-f increased from 9.5 to 11% with increasing rod diameter from 1 to 2 mm. The in-situ bee phase has a dendritic morphology with a size of about 10 pro and its size tends to increase with increasing V-f. The bee phase has analytical compositions of 1.4at% Cu, 7.6at% Ti and 91.0at% Ta. The lattice parameter of the bee phase is 3.306nm which approximates to that of Ta metal. The thermal stability of the remaining glassy matrix remains unchanged in coexistence with the bee phase. The mixed structure is presumed to be formed by the primary precipitation of ductile dendritic bee phase, followed by the solidification of the remaining liquid to glassy phase. The Young's modulus (E), yield strength (sigma(y)), true compressive fracture strength (sigma(t,f)) and true plastic strain (epsilon(p)) were 104 GPa, 2125 MPa, 2100 MPa and 0.34, respectively, for the phi2 mm rod with 11% V-f. The sigma(y) and sigma(t,f) are higher than those (2010 MPa and 2005 MPa) for the Cu60Hf25Ti15 glassy alloy rod with a diameter of 2 mm. Especially, the epsilon(p) for the (Cu0.6Hf0.25Ti0.15)(94)Ta-6 mixed structure alloy is dramatically enhanced in compari son with that (epsilon(p) = 0.016) for Cu60Hf25Ti15 single phase alloy. The enhancement of sigma(y), sigma(t,f) and epsilon(p) in the mixed structure of glassy and bcc phase for the new Cu-based system is promising for future uses as a new type of high-strength bulk glassy alloy.
10.2320-matertrans.45.411	-1		Secondary ion mass spectrometry (SIMS) has been used for characterizing the depth distribution of alloying elements in three different copper-based dilute alloys, i.e. copper-chromium, copper-iron and copper-nickel-silicon alloys, which were annealed at high temperatures under low oxygen partial pressure. SIMS depth profiles showed that oxygen penetrated into the copper-based alloys, and chromium and silicon were enriched to the surface side so as to form oxides during annealing. Chromium and silicon were depleted beneath the enriched layer. On the other hand, depth profiles of iron and nickel were similar to that of copper. These phenomena were likely to be associated with the reactivity of alloying elements with oxygen. The formation kinetics of the depleted zones of chromium and silicon was discussed coupled with the selective oxidation of these alloying elements.
10.2320-matertrans.45.75	-1		Effects of Ni and Al addition on the mechanical and electrical properties in the Cu-15 mass%Cr in-situ composite are examined. The process consists of melting, hot forging, heavy cold rolling and aging. Ni is partitioned into the Cr phase to make an intermetallic precipitates. The Cr phase in the Cu-15 mass%Cr-10 mass%Ni shows 3.6 times harder compared with the Cu matrix resulting in the poor cold drawability and low strength . The addition of 1 mass% Ni and 0.15 mass%Al is recommended to get good cold drawability and high strength, but it is necessary to make a compound such as Ni3Al to increase the electrical conductivity.
10.2320-matertrans.46.798	11	glass; bulk; metallic; bulk metallic; gfa; bmg; glassy; metallic glass; ability; bulk metallic glass; amorphous; addition; crystallization; mm; glass-forming	Multi-component Cu-Hf-Ti-Ag-Ta bulk metallic glass (BMG) composites containing in situ formed Ta-rich dendrites were prepared successfully. Composition analysis shows that about 7 similar to 11 at% component elements (Ti, Cu and Ag) were detected in Ta-rich dendrites, but no Hf element was found. With increasing the volume fractions of the dendrites (V-dendrite) the content of component elements dissolving into Tarich dendrites decreases from 11.35 at% for V-dendrite = 4.3% and 7.97 at% for V-dendrite = 26.5%. Indentation testing was also performed to evaluate the properties of the composites. With increasing V-dendrite the hardness of the dendrites decreases from 6.0 GPa for x = 3 to 5.21 GPa for x = 12, and its elastic modulus increases from 151.2 GPa for x = 3 to 156.9 GPa for x = 12. The hardness and elastic modulus of the glassy matrix also decrease from 9.66 GPa and 148.7 GPa for x = 0 to 9.36 GPa and 137.4 GPa for x = 12 with increasing the precipitation of the dendrites. The variation of the properties is due to the compositional change originating from the opposite behavior of Hf and Ti elements to dissolve into the dendrites.
10.2320-matertrans.46.88	-1		A mathematical model is developed in this study to simulate the morphological change of the sintering neck by neck growth and the Kirkendall void formation in the Cu-Ni interdiffusion system. The fluxes of materials and vacancy are analyzed for estimating excessive deficient vacancy regions. The Multi-Layered Potts Model (MLP Model) is used as the mathematical model. The MLP Model is an improved model of the traditional Potts Model which can treat multiple materials transportation mechanisms such as interdiffusion system. The Potts Model uses a two dimensional (2-d) array to describe a 2-d microstructure, on the contrary, the MLP Model uses a three dimensional ( 3-d) array which stacks several 2-d arrays. The MLP Model of present study could treat an interdiffusion and an intrinsic diffusion coeflicient is a function of the local alloy component. The morphological change and analyzed materials and vacancy fluxes of the simulation results are compared with the experimental results. then good agreements is observed.
10.2320-matertrans.47.1922	11	glass; bulk; metallic; bulk metallic; gfa; bmg; glassy; metallic glass; ability; bulk metallic glass; amorphous; addition; crystallization; mm; glass-forming	The thermal stability, crystallization behavior and mechanical properties of the Cu45Zr45-xHfxAg10 (x = 0 to 45 at%) glassy alloys have been investigated. The glass transition temperature (T-g), crystallization temperature (T-x), liquidus temperature (T-l) and the supercooled liquid region Delta T-x (= T-x-T-g) increase with increasing Hf content. The reduced glass transition temperature (T-g/T-l) values are in the range from 0.54 to 0.59. The Vicker's hardness (H-V), Young's modulus (E) and compressive fracture strength (sigma(c,f)) of the Cu45Zr45-xHfxAg10 (x = 0 to 25 at%) bulk glassy alloys increase linearly with increasing Hf content and reach the maximum values of 554, 123 GPa and 2020 MPa, respectively, for Cu45Zr20Hf25Ag10 alloy. A different crystallization behavior is observed for Cu45Zr45Ag10 and Cu45Hf45Ag10 glassy alloys.
10.2320-matertrans.47.2427	-1		A DSC scan of a Cu-33.5Zn-4Sn (mass%) alloy shows two exothermic peaks at around 250 and 300 degrees C. The first peak is associated with the precipitation of alpha(1)-plates with M9R structure, and the second peak is associated with the formation of gamma precipitates. For the first peak, the alpha(1)-plates start to nucleate at grain boundaries and grow dendritically upon heating. The primary and secondary arms of the dendritic alpha(1)-plates grow in two preferred directions, namely, [110](B2) and [100](B2) of the beta' matrix. However, the stacking faults in the two arms are parallel and differ from those with the structure of the twin-accommodating variants. As the thickness and number of alpha(1)-plates increase, the hardness of the alloy increases significantly; however, the recovery strain reduces dramatically. Additionally, the gamma precipitates nucleate heterogeneously at the interface between the alpha(1)-plate and the beta' matrix on heating above 300 degrees C. The volume fraction of the gamma precipitates increases with temperature, resulting in a reduction in the ductility of the alloy and a complete loss of its shape memory effect.
10.2320-matertrans.47.2480	-1		Using Cu/Al diffusion couples initially composed of pure Cu and Al, the reactive diffusion in the binary Cu-Al system was experimentally examined in a previous study. The diffusion couple was isothermally annealed in the temperature range of T = 973-1073 K. Due to annealing, compound layers of the beta, gamma and epsilon phases are formed between the Cu-rich solid (alpha) phase and the Al-rich liquid (L) phase, and the L/epsilon interface migrates towards the epsilon phase. At each annealing time, the migration distance of the L/epsilon interface is much greater than the total thickness of the compound layers. Furthermore, there exists the parabolic relationship between the migration distance and the annealing time. This means that the migration of the interface is controlled by the volume diffusion in the L phase. The mathematical model for the interface migration controlled by volume diffusion was used in order to analyze quantitatively the migration rate of the interface. Through the analysis, the interdiffusion coefficient D of the L phase was evaluated to be 1.24 x 10(-9), 2.91 x 10(-9) and 3.62 x 10(-9) m(2)/s at T = 973, 1023 and 1073 K, respectively. Expressing the temperature dependence of D as D = D-0 exp(-Q/RT), values of D-0 = 1.42 x 10(-4) m(2) Is and Q = 93.5 kJ/mol were obtained by the least-squares method. According to the analysis, the interdiffusion coefficient is much greater for the L phase than for the solid phases. Consequently, the L/epsilon interface migrates towards the L phase, and the migration rate of the interface is much greater than the overall growth rate of the compound layers.
10.2320-matertrans.47.2925	-1		The precipitation processes in a Cu-0.9 mass%Be alloy single crystal containing only G.P. zones parallel to the matrix (00 1), plane have been studied by high-resolution transmission electron microscopy. The precipitation sequence found is: G.P. zones -> gamma -> gamma'(I) -> gamma(I) + gamma' -> y. The gamma phase has a two-layer structure of Be atoms separated by a matrix layer parallel to (001)(alpha), and a body-centered tetragonal (bct) lattice. The gamma'(I) phase consisting of five to ten Be-layers is body-centered monoclinic. The gamma(I) phase continuously transforms from the G.P. zones via gamma and gamma'(I). The heterogeneous formation of gamma' occurs on the gamma(I) phase. The gamma(I) or gamma' phase is bct with a = b = 0.254 nm and c = 0.352 nm or a = 0.254 nm and b = c = 0.268 nm. The gamma, gamma'(I) or gamma(I) phase aligns with the matrix according to-the Bain orientation relationship. The plate-shaped gamma' precipitates have the (1 (1) over bar(2) over bar)(alpha). habit plane and-the orientation relationship, (1 (1) over bar(2) over bar)(alpha) // (0 (1) over bar(2) over bar)(gamma'); [110](alpha) // [100](gamma') (OR I), or the (1 (1) over bar3)(alpha) habit plane and the orientation relationship, (1 (1) over bar3)(alpha) // (0 (1) over bar3)(gamma'); [110](alpha) // [100](gamma') (OR II). The structure of gamma' successively changes into that of the gamma phase with a = 0.280 not for OR I or 0.268 nm for OR II. The gamma precipitates of OR I and OR II are elongated along approximately [1 (1) over bar1](alpha) and [3 (3) over bar(2) over bar](alpha), which are in good agreement with the invariant-line directions.
10.2320-matertrans.47.2950	12	thermodynamic; ternary; phase; data; experimental; equilibria; phase equilibria; liquid; binary; experimental data; calculated; phases; literature; model; calphad	A thermodynamic analysis of the undercooled liquid and glass transition in the ternary Cu-Mg-Y system has been carried out. To this purpose, a number of experimental data on the amorphous phase and on the undercooled liquid has been considered (glass transition temperatures, specific heat). A proper modelling of the glass transition has been applied, which has been proved suitable for the description of thermodynamic properties of the liquid-amorphous phase. Calculated and experimental quantities show a good agreement. An improved description of the behaviour of the specific heat of the liquid phase on undercooling has been obtained. The present thermodynamic assessment is suitable for estimating the Glass Forming Ability in this ternary system.
10.2320-matertrans.48.101	-1		Analyses of small-angle X-ray scattering (SAXS) and X-ray absorption fine structure (XAFS) were performed for characterizing precipitates formed in a Cu-3.1 at%Ni-1.4 at%Si alloy. the strength and electrical conductivity of which were improved by aging. SAXS profiles and XAFS spectra of samples aged at 720 K for different periods of time after a solution treatment were measured. SAXS profiles of samples, which were aged after the solution treatment and Subsequently cold rolled, were also measured to investigate the effect of dislocations on precipitation. The results of SAXS measurements showed that nanometer-size precipitates formed in the alloy samples during isothermal aging at 720 K. The precipitates in the samples without cold rolling were coarsened in a single modal size distribution with increasing aging time. In contrast, the precipitates formed in the cold-rolled samples appeared to be coarsened in a multi-modal size distribution with increasing aging time. This aging characteristic of the cold-rolled samples is presumably attributable to their good electrical conductivity. The results of XAFS measurements at the Ni K-edge showed that nickel was Substituted for copper in the face-centered cubic (fee) copper matrix and that the local structure around nickel was changed by isothermal aging. With increasing aging time, extended X-ray absorption line structure (EXAFS) functions at the Ni K-edge of the samples were found to be changed, which implies that nickel atoms were precipitated as nickel-silicon Clusters or intermediate compounds in the fee copper matrix. In addition, X-ray absorption near edge structure (XANES) spectra at the Ni K-edge indicated that the electronic Structure of nickel in the samples was influenced by silicon during aging.
10.2320-matertrans.D-MA201031	-1		influence of hydrogen pressure during isothermal aging on the mechanical strength, electrical conductivity, and microstructure of Cu-3 at% Ti alloys was investigated under various hydrogen pressures from 0 to 0.8 MPa. The variation of hardness with aging time was not significantly different among all specimens aged under the hydrogen pressures. This is because the hardness is improved primarily by the precipitation strengthening of Cu4Ti particles, which is less affected by hydrogen pressure. The electrical conductivity increased more significantly for specimens aged under higher hydrogen pressure, due to a rapid reduction in the concentration of Ti dissolved in the matrix, which is attributed to the accelerated formation of TiH2. The conductivity at peak-hardness was improved by a factor of approximately 1.4 in the specimens aged at both 773 and 723 K under the highest hydrogen pressure, compared to that for the specimen aged in vacuum. Therefore, aging under high hydrogen pressure assisted in the significant improvement of both strength and electrical conductivity. [doi: 10.2320/matertrans.D-MA201031]
10.2320-matertrans.M2010139	-1		A significant number of nanotwins was fabricated in a cold-rolled Cu-Zn alloy after an electric current pulse (ECP) treatment in this study. Results showed that the formation of nanotwins was related not only to the alpha to beta phase transformation, but also to the effect of the enhanced directional nucleation along the current direction during the heating caused by the ECP treatment. A theoretical analysis revealed that the nucleation rate of the higher conductivity phase (beta phase) was significantly accelerated by the application of an electric current, which provided more nucleation places for the alpha phase during the subsequent rapid cooling process. Especially, during the cooling process, nanotwins with {111} twin planes in the alpha phase would be formed due to the stronger internal stress induced by the rapid cooling rate after the ECP treatment. [doi:10.2320/matertrans.M2010139]
10.2320-matertrans.M2010270	16	wear; composite; composites; powders; milling; particles; powder; wt; sliding; friction; hardness; matrix; mechanical; surface; properties	Two types of milled process are used in SPS to prepare TiC reinforcement Cu matrix composites: (a) Ti and C powders are milled together, and then mixed with Cu powders; (b) All the three kinds of powders are milled together. The microstructures of specimens were analyzed with XRD, SEM and TEM. The pin-disk wear test was carried. It was found that TiC reinforcement formed in sintering by direct reaction in the method (a). However, in method (b), diffused reaction mechanism has also been confirmed in TiC forming process. All the composites exhibit good wear resistance at 200N normal load with lowest wear lose 1.4 x 10(-5) mm(3)/Nm (method (a)) and 1.12 x 10(-5) mm(3)/Nm (method (b)) respectively. The composite sintered from the powders of the method (b) shows lower wear lose and a steadier friction coefficient at even normal load then the composites sintered from the other powders which show third body abrasion in wear test. [doi:10.2320/matertrans.M2010270]
10.2320-matertrans.M2010332	-1		Among the large number of superlattices, there is a special group which may be classified as long period superlattices, the copper-gold system provides a classical example of such structure. Despite that historically, the copper-gold alloys containing about 25 atom percent gold were among the first investigated alloys, it still represents a subject of numerous studies. In the present work, we study all the possible phase transitions in the binary intermetallic alloy Cu3Au using differential scanning calorimetry (DSC) and differential dilatometry. A new important anomaly due certainly to a new ordered reaction has been detected at low temperature range by these two methods. To confirm this new reaction, we have used other techniques as high resolution transmission electron microscopy (HRTEM), electrical resistivity and microhardness measurements. The kinetics parameters as activation energy E-act and Avrami exponent n have also been calculated respectively by Starink and John Mehl Avrami Kolmogorov (JMAK) methods. [doi:10.2320/matertrans.M2010332]
10.2320-matertrans.M2010356	-1		Thin films of Pd-Cu-Si metallic glassy alloys of varying composition were prepared by simultaneous three sources (Pd, Cu and Si) sputtering method using a rotating mechanism of substrates. Their H-2 responses were observed by measuring the electric resistance changes of them exposed in N-2 and H-2. In addition, their linear expansion coefficients (LECs) induced by absorbed hydrogen were also measured. Contrary to a normal H-2 response transient with a rapid increase in electric resistance of a thin film, several thin films indicated abnormal H-2 response transients consisting of complex changes, an increase and a decrease, in electric resistance when the thin films were exposed in H-2. These thin films have higher Pd/Si atomic ratios than those indicated normal H-2 response transients. Additionally, by the characterization of the thin films, the existence of Pd-nanocrystals of about 2 nm in diameter was observed in the amorphous matrix which possibly includes Pd-clusters as well as Pd atoms. The mechanism of the abnormal H-2 response transient can be explained by two conflicting behaviors in electric resistance of the thin films when they are exposed in H-2: a decrease by the formation of electrical contacts of Pd-nanocrystals connected with volume expanded Pd-clusters by hydrogen absorption and a following increase by hydrogenation of Pd-nanocrystals. Observed time lags between two conflicting behaviors can be explained by the different transfer speeds of hydrogen relating to two kinds of pathways: inside of Pd-nanocrystals and the amorphous matrix along which hydrogen atoms transfer in the structure. The Pd-nanocrystals also affected on LEC and the H-2 response significantly. The thin films with them indicated much higher LEC than the thin films without them. However, the thin films with them did not indicate the high H-2 response expected from their high LEC. The result of LEC suggests that Pd-nanocrystals can absorb much more hydrogen atoms than Pd in an amorphous matrix. The Pd in an amorphous matrix is supposed to be Pd-clusters, randomly distributed Pd atoms and Pd atoms forming a trigonal prism that is a structural unit of the Pd-Cu-Si alloys. On the other hand, the high H-2 response according to the high amount of absorbed hydrogen can not be expected in the thin films with Pd-nanocrystals, due to a decrease in electric resistance by forming electrical contacts of the Pd-nanocrystals. [doi:10.2320/matertrans.M2010356]
10.2320-matertrans.M2010360	4	transformation; martensite; martensitic; phase; shape; beta; memory; shape memory; temperature; temperatures; martensitic transformation; gamma; transformation temperatures; effect; thermal	Acoustic emission is defined as the ultrasonic wave phenomenon due to rapid release of strain energy in the solid materials. This paper aims at the extension of acoustic emission method for certain and effective analysis that can adapt to material research field. The rise time of two kinds of martensitic transformation in Cu-Al-Ni shape memory alloy, the beta(1) to beta(1)' and the beta(1) to gamma(1)' phase transformation, were observed by acoustic emission monitoring and the analysis based on the simulation of acoustic emission wave utilizing finite element method. In the simulation on finite element method, we considered the acoustic emission wave with the effect of inclined source such as the martensitic habit plane, source location in thickness direction of the specimen and rise time of acoustic emission source as the dynamic behavior. We found that the particular frequency range of zeroth-order mode Lamb wave has the differences only due to rise time of acoustic emission source. Finally we analyzed the rise time of two kinds of martensitic transformation with reviewing the results of simulation. As the result, the beta(1) to beta(1)' phase transformation showed the longer rise time than the beta(1) to gamma(1)' phase transformation in the nucleation step. It is thought that there is the difference between 18R and 2H periodic stacking order structure of martensite. [doi:10.2320/matertrans.M2010360]
10.2320-matertrans.M2010406	-1		The aim of this work was to evaluate the effects of strain rate on the microstructural evolution of 5-mm-thick pure copper (99.99%) sheets subjected to conventional rolling (CR) and cross-roll rolling (CRR). The sheets were cold-rolled with a reduction ratio of 90% and then annealed at 400 C for 30 min to obtain the fully recrystallized microstructures. The resulting cold-rolled and annealed sheets had considerably finer grains than the initial sheets. In particular, the average grain size became smaller by CRR (6.5 mu m) than by CR (9.8 mu m). The mechanical properties of the sheets, i.e., Vickers microhardness and tensile strength, were more enhanced by CRR than by CR. The microstructural development in these processes was systematically discussed. [doi:10.2320/matertrans.M2010406]
10.2320-matertrans.M2012025	13	clusters; atomic; glass; atoms; composition; dynamics; metallic; icosahedral; glasses; simulations; molecular; cu-zr; molecular dynamics; metallic glasses; structural	Molecular dynamics (MD) simulations based on a plastic crystal model (PCM) were performed for a Cu0.618Zr0.382 binary bulk metallic glass (BMG). The local atomic arrangements of the Cu0.618Zr0.382 BMG were demonstrated with MD-PCM under an assumption that the BMG is composed of randomly-rotated as well as distorted hypothetical clusters. The Cu-rich Cu0.618Zr0.382 alloy was computationally created from a tentatively-created Zr-rich Zr0.73Cu0.27 alloy through two steps. The first step includes the Zr0.73Cu0.27 alloy quenched from a liquid through conventional MD simulation, whereas the second step has a replacement of the Zr and Cu atoms in the Zr0.73Cu0.27 alloy with randomly-rotated icosahedral and tetrahedral clusters, respectively, and subsequent structural relaxation. The Cu0.618Zr0.382 alloy, thus created with MD-PCM, was formed in a noncrystalline state as a critically-percolated cluster-packed structure. The analyses with total pair-distribution and interference functions revealed that the calculation results tend to reproduce the experimental data in an as-quenched state. The results explain that the glass-forming ability of the Cu0.618Zr0.382 BMG is due to (1) a critically-percolated and distorted tetrahedral clusters forming a network and (2) atomistic-level inhomogeneity for the local atomic arrangements with keeping macroscopic homogeneity in terms of the chemical composition and dense random atomic arrangements. [doi:10.2320/matertrans.M2012025]
10.2320-matertrans.M2012207	6	grain; deformation; strain; strength; dislocation; cu-; tensile; size; ecap; grain size; sfe; ductility; hardening; high; stress	The enhancement in tensile properties of a Cu-2.0 mass% Ni-0.5 mass% Si-0.1 mass% Zr alloy without reducing its electrical conductivity is attempted by combining both accumulative roll-bonding (ARB) and cryo-rolling with aging treatment. The grain sizes of the alloy pre-aged at 450 degrees C and ARB-processed in six cycles (P-ARB) and of the alloy pre-aged at 450 degrees C and cryo-rolled to a 90% reduction (P-90CR) are refined to about 0.1 and 0.2 mu m, respectively. Both six cycles of ARB and 90% cryo-rolling, together with the presence of fine precipitates formed by pre-aging at 450 degrees C, give significant grain refinement. The P-90CR alloy aged at 350 degrees C exhibits a higher 0.2% proof stress of 830 MPa and a higher tensile strength of sigma(u) = 900 MPa than the P-ARB alloy aged at 375 degrees C. The aged P-90CR alloy exhibits almost the same elongation of 6% up to failure and the same electrical conductivity of sigma = 45% IACS as the aged P-ARB alloy. The higher proof stress of the aged P-90CR alloy than the aged P-ARB alloy is ascribed to the higher dislocation density in the aged P-90CR alloy. The value of sigma(u) = 900 MPa for the aged P-90CR alloy is larger than that of sigma(u) approximate to 830 MPa for conventional commercial Cu-3.0 mass% Ni-0.65 mass% Si system alloys. The value of sigma for the former alloy is nearly identical to sigma approximate to 46% IACS for the latter alloys.
10.2320-matertrans.M2012375	11	glass; bulk; metallic; bulk metallic; gfa; bmg; glassy; metallic glass; ability; bulk metallic glass; amorphous; addition; crystallization; mm; glass-forming	(Cu46Zr46Al8)(100-x)Co-x (x = 0, 1, 2, 3 and 4) bulk metallic glasses (BMGs) were synthesized by copper mold casting, and the effect of Co addition on the microstructure and mechanical properties of Cu46Zr46Al8 BMG was investigated. The existence of immiscibility gap between Co and the main component Cu is responsible for liquid separation to form droplet-type structure during solidification. The size scale for the droplet-type structure trends to increase with the Co concentration. Depending on the glass-forming ability of the separated liquid phase, amorphous/amorphous or amorphous/crystalline composite structure can be obtained. The results of compression test reveal that the plasticity and the fracture strength can be simultaneously enhanced with an appropriate amount of Co addition owing to nanoscale phase separation with the formation of Cu-rich and Co-rich glassy phases.
10.2320-matertrans.M2012423	-1		We have investigated the specific contributions of titanium-hydride precipitates to the improvement of electrical conductivity and strength for Cu-0.36 mol% Ti alloys aged in a hydrogen atmosphere at 773 K, where Cu4Ti phase is not to appear. During the aging, titanium-hydride particles, which have a composition of H/Ti = 2, are formed by reaction of solute titanium with hydrogen diffused into the alloy. The particles have an octahedral shape with facets parallel to {111} of the matrix. The size and volume fraction of the hydride particles increase with aging time, and then level off after aging for 100 h, while the number density exhibits a maximum at 24 h . The precipitation reduces the concentration of solute titanium in the matrix and leads to significant improvement of the electrical conductivity, to the level comparable to pure copper. The dispersed TiH2 particles gives rise to strengthening with the Orowan mechanism, of approximately 40 MPa at a maximum in yield strength .
10.2320-matertrans.M2014203	-1		In this work, TiC coating on a copper alloy electrode, which is prepared by a special electron-spark deposition process (ESD), was modified by friction stir processing (FSP). The microstructure evolution of the coating was investigated, while the mechanical properties of the coating and interface were measured. The results show that FSP eliminates the cracks within TiC coating and improves the interface bonding between the TiC coating and substrate. The hardness of the FSPed TiC coating is increased about 800 HV by decreasing cracks. The elimination of the cracks within the coating is ascribed to the thermal-mechanical effect on the coating during the FSP. The increase in hardness is attributed to the decreasing number of cracks and the disappearance of columnar Cu grains, which are modified by FSP.
10.2320-matertrans.M2014234	-1		We investigate early stages of spinodal decomposition in a melt-spun Cu-15Ni-8Sn alloy (melt-spun samples) by X-ray diffraction (XRD) analysis, transmission electron microscopy (TEM) and electron diffraction analysis through comparison against a non-melt-spun alloy of the same composition (quenched samples). In XRD measurements, no sidebands of (200) planes are found in the melt-spun sample after aging at 350 degrees C for 120 min, whereas they are found in the quenched sample after a heat treatment at 350 degrees C for 60 min. TEM observations of a quenched sample after aging at 350 degrees C for 60 mm indicate the presence of a modulated structure (lambda = 5-10 nm) in the matrix, whereas those of a melt-spun sample after the same heat treatment also indicate the presence of a modulated structure (lambda: too small to measure). Electron diffraction patterns reveal satellite structures in both samples, although with superlattice reflections from ordering phases visible in the quenched sample. These differences are presumably due to a difference in the size of clusters present in their respective quenched states; in melt-spun samples, cluster size was much smaller as a result of a high cooling rate (approximate to 8 x 10(5)degrees C/s).
10.2320-matertrans.M2017178	6	grain; deformation; strain; strength; dislocation; cu-; tensile; size; ecap; grain size; sfe; ductility; hardening; high; stress	Solution-treated Cu-1.8 mass% Be-0.2 mass% Co and Cu-3 mass% Ti alloys were subjected to severe plastic deformation using high-pressure torsion (HPT) process to examine the change in densities of grain boundary, dislocation and vacancy during natural aging of the two alloys at 293 K after HPT-straining, and the influence of the natural aging on the age-hardening behavior of the alloys on subsequent artificial aging. Application of HPT processing under an applied pressure of 5 GPa for 10 revolutions at 1 rpm to each alloy produced an ultrafine-grained structure. Aging the HPT-processed alloys at 293 K for the longest period of 2.59 Ms (1 month) did not essentially change the dislocation densities and grain sizes of the alloys; however, the vacancy concentrations of the alloys gradually decreased with increasing natural aging time. The attained peak hardness of the Cu-Be-Co alloy on subsequent artificial aging at 593 K decreased as natural aging time increased, while the natural aging at 293 K for 2.59 Ms had no influence on the age-hardening behavior of the Cu-Ti alloy during artificial aging at 623 K. This result is ascribed to the difference in formation mechanisms of strengthening precipitates between two alloys; G.P. zones are directly formed in Cu-Be-Co alloy while beta'-Cu4Ti phase is formed via spinodal decomposition without nucleation events in Cu-Ti alloy.
10.2320-matertrans.M2017196	2	corrosion; surface; film; electrochemical; films; spectroscopy; layer; current; solution; potential; resistance; composition; x-ray; ions; showed	In this study, we aimed to understand the corrosion behavior of Pb-free Cu alloys (Japan Industrial Standards (JIS) CAC411 and CAC901) and their crystallized substances (Cu2S and Bi, respectively) particles in a 3.0 mass% NaCl aqueous solution, in comparison with those of a Cu alloy (JIS CAC406), its crystallized substance (Pb) particles, and a Cu alloy (JIS CAC403) with no crystallized substances. A Cu2S specimen was produced via sintering Cu2S powders, and a Bi specimen was produced by Bi electro-plating on a Cu substrate. The measured corrosion potentials of CAC411, CAC901, and CAC403 were close to that of Sn instead Cu. The current density peak near the corrosion potential of CAC403, which was the highest Sn concentration, was the largest in comparison with those of the other Cu alloys. Conversely, rapid increase in the current density, which was shown for all the Cu alloy at the potential above -0.20 V vs. Ag/AgCl, was similar to that of Cu. Therefore, it was concluded that these increase in current densities of Cu alloys was due to the dissolution of the Cu matrix. Cu2S was converted into CuS during the anodic reaction. However, the corrosion potential of Cu2S was higher than those of Cu and CAC411. Therefore, it was concluded that the Cu2S particles in CAC411 act as cathodic sites and remain stable during the natural corrosion. The corrosion potential of Bi was higher than that of CAC901 and slightly lower than that of Cu. Further, at the potentials below -0.10 V vs. Ag/AgCl, Bi was thought to be covered with the passive film of Bi2O3 that was expected to protect Bi from corrosion. Therefore, it was concluded that the Bi particles in CAC901 hardly suffer severe corrosion. The corrosion potential of Pb was lower than those of the Cu and Cu alloys expect for CAC406. In addition, Pb exhibited a large anodic current density and dissolved actively around the corrosion potential of Cu. Therefore, it was concluded that the Pb particles dissolved preferentially during the corrosion of CAC406 owing to the galvanic corrosion. It was finally concluded that the Cu2S and the Bi particles in CAC411 and CAC901, respectively, hardly suffer severe corrosion than the Pb particles in CAC406 in chloride-containing aqueous solutions like sea water.
10.2320-matertrans.M2017287	-1		This study investigated the selective leaching, chemical compositions, and electrochemical properties of Cu-XAl-4Ni (X = 12.5, 13.0, and 13.5) shape memory alloys (SMAs). The selective leaching results showed that the Cu-XAl-4Ni SMAs released approximately 200 ppb of Cu ions, 200 ppb of Al ions, and 600 ppb of Ni ions after immersion in Ringer's solution for 90 days. The low concentrations of Cu and Al ions stem from the oxidation of Cu and Al atoms near the surface of the Cu-XAl-4Ni SMAs to form Cu2O and Al2O3 films. The selective leaching properties of the Cu-XAl-4Ni SMAs were inferior to that of the TiNi SMA, which possessed a highly passive TiO2 film on the surface, but were much better than those of the TiNiCu and TiNiFe SMAs, whose TiO2 films were deteriorated by the formation of NiO, Cu2O, and Fe2O3 oxides. Cu-XAl-4Ni SMAs are potential candidates to serve as biomaterials, owing to their acceptable surface and selective leaching properties, high martensitic transformation temperatures, low cost, good machinability, and excellent electric and thermal conductivities.
10.2320-matertrans.M2018081	-1		Typically, bismuth added in traditional Cu-Zn brass segregates as films or particles along the alpha-beta phase boundary and induces cracks after casting. The present work investigated the bismuth formation in lead-free Cu-Zn-Si yellow brass with various amounts of recycled bismuth-tin (Bi-Sn) solder. The results showed that no bismuth film segregated at the phase boundaries. In contrast, round particles of bismuth formed in the beta phase and at the alpha-beta phase boundaries when added 1 mass% Bi-Sn alloy and the bismuth particles embedded only in the alpha phase when added 2 to 4 mass% Bi-Sn alloy, respectively. The morphology of the fracture surfaces was significantly modified when Bi-Sn alloy content was increased. More importantly, there was no crack observed in as-cast samples and samples did not subject to any heat treatment process unlike the bismuth formation in other work. Thus, this work suggests that the addition of recycled Bi-Sn solder in lead-free Cu-Zn-Si yellow brass is beneficial to avoid cracks in castings and offer an original lead-free brass alloy with superior properties.
10.2320-matertrans.M2018255	-1		We have examined solid solubility extension for melt-spun Cu-Ti alloys (4, 6, 7, and 8 mass% Ti) in comparison with that for conventional quenched alloys. X-ray diffraction (XRD) measurements revealed that the solid solubility extension for the melt-spun alloys was in the range of 7-8 mass% Ti, whereas that for quenched alloys was less than 6 mass% Ti. After annealing the melt-spun alloys at 673 K, the XRD measurements revealed sidebands with no intermetallic compound peaks, bright-field transmission electron microscopy images showed modulated structures, and selected-area diffraction patterns exhibited satellite structures; taken together, these experimental results confirm the occurrence of spinodal decomposition. In this study, however, distinct superlattice reflections were not observed.
10.2320-matertrans.MA201205	6	grain; deformation; strain; strength; dislocation; cu-; tensile; size; ecap; grain size; sfe; ductility; hardening; high; stress	The influence of texture on the bendability in Cu-Ni-Si alloys was examined by using an age-hardened polycrystalline strip with various recrystallization textures. In multiple samples manufactured by adjusting conditions of rolling and heat treatment, the Cube orientation {100{< 001 >, the RD-rotated Cube orientation {012}< 100 >, the BR orientation {362}< 853 > and the R(S) orientation {231}(346), which are the representative recrystallization textures of FCC metals, developed up to 40% in respective area fractions. The bendability was clearly dependent on texture. The sample that had a strongly developed Cube orientation showed the best bendability with respect to both the good and bad ways (GW, BW) in bending. In comparison, the samples in which the BR and the R orientations developed showed poor GW bendability. The sample having a comparably random orientation showed poor GW and BW bendability. The shape of the cracks generated by bending was linear, and these cracks developed in a direction about 40 degrees from the surface. Further, they developed along shear bands, and this result was confirmed by the EBSD measurement. Therefore, the cause of cracking resulting from bending was shear bands. The correlation between the good bendability and a low average Taylor factor was confirmed. More uniform deformation by crystalline slips through texture control was effective for restraining the shear bands, i.e., for obtaining excellent bendability. [doi:10.2320/matertrans.MA201205]
10.2320-matertrans.MBW200736	-1		Nanostructural evolution of Cr (Cr-rich) precipitates in a Cu-0.78%Cr-0.13%Zr alloy has been studied after aging and overaging (reaging) by laser assisted local electrode 3 dimensional atom probe (Laser-LEAP). This material is a candidate for the first wall and divertor components of future fusion reactors. After prime aging at 460 degrees C, Cr precipitates enriched with Zr were observed. Further reaging at 600 degrees C caused the precipitates to grow to almost spherical Cr precipitates with 5 nm (1 h) in diameter and plate-like ones with 20 nm (4 h), respectively. Zr and impurities of Si and Fe were concentrated around the Cr precipitates, resulting in an almost pure Cr cores with interface regions enriched with Zr and the impurities. Probably, the strain induced by the incoherency of BCC Cr with matrix FCC Cu is relaxed by the formation of the enriched regions.
10.2320-matertrans.MC201706	-1		We investigated the microstructural subsequence and phase equilibrium of Cu-4.3 at% Ni-2.2 at% Si alloy specimens during isothermal aging over a temperature range of 698 K to 873 K. During aging in this temperature range, the microstructure of the specimens evolved in the following sequence; continuous precipitation of fine disk-shaped delta-Ni2Si in the matrix, discontinuous precipitation of cellular components containing coarse fiber-shaped delta-Ni2Si at grain boundaries, and then occupation of the specimen with cellular components. By analyzing the variations in the hardness and electrical conductivity with aging time as well as temperature, we described the kinetics of the highest number density of fine delta-Ni2Si continuous precipitates. Based on the chemical analyses of the specimen in a phase equilibrium state using an extraction procedure, we proposed a revised solvus of solutes Ni and Si in the Cu solid solution phase, as well as Cu in the d-Ni2Si intermetallic phase in a Cu-delta-Ni2Si pseudo-binary system.
10.2320-matertrans.MD201114	-1		The changes in mechanical properties and microstructures of fine Cu-Sn alloy wires manufactured by deep wire drawing and heat treatment, and of the wires deformed by draw bending were systematically investigated. During draw bending, the wires were subjected to the compressive/tensile or tensile/compressive strain in the longitudinal direction. As a result, it was confirmed that the softening caused by plastic deformation was induced when easing up the wire drawing strain by heat treatment were few, such as the decreasing strength and increasing elongation. Work hardening was induced when easing up the wire drawing strain by heat treatment were large, such as the increasing strength and decreasing elongation. With decreasing strength of softening induced by plastic deformation, increase in grain size is smaller than the strength deterioration. Additionally, it was confirmed that the occupancy probability of high-angle grain boundaries increases. This can be understood by considering that the many dislocations formed inside the grains are piled up in one direction during draw bending. Additionally, it is considered that ductility enhancement is caused by the increase in work hardening rate induced by the piled up dislocations. [doi:10.2320/matertrans.MD201114]
10.2320-matertrans.MEP2007099	11	glass; bulk; metallic; bulk metallic; gfa; bmg; glassy; metallic glass; ability; bulk metallic glass; amorphous; addition; crystallization; mm; glass-forming	We report a particulate-reinforced bulk metallic glass composite with high strength and unusual plasticity, which consists of Ta particles homogenously distributed in Cu36Zr48Al8Ag8 glassy matrix. The glassy matrix remains amorphous even after adding up to 15 vol.% of Ta particles. A largest plastic strain of up to 31% was obtained for the 10% Ta-containing composite. Ta particles seed the initiation of multiple shear bands and block the shear band propagation, leading to a net-like homogeneous distribution of the shear bands.
10.2320-matertrans.MF201904	6	grain; deformation; strain; strength; dislocation; cu-; tensile; size; ecap; grain size; sfe; ductility; hardening; high; stress	Microstructure and mechanical properties induced either by heavy cold rolling or multi-directional forging of Cu-Al alloy were investigated and compared. While both microstructures were developed mainly by a mechanism of mechanical twinning, the features were completely different. The former exhibited a typical heterogeneous nano-structure where eye shaped twin domains were surrounded by deformation bands and they were further embedded in low-angle lamellae. The latter also showed complicated feature where twin domains and ultrafine grains composed of equi-axed nano-grains were randomly distributed. Even while the latter possessed finer grain size, the former showed more superior mechanical properties, yield strength of 863 MPa and ultimate tensile strength of 1168 MPa than the latter, yield strength of 720 MPa and UTS of 870 MPa.
10.2320-matertrans.MF201944	-1		Although the maximal strength of Cu with a mean grain size of 10 nm has been reported as similar to 1000 MPa, the maximal strength of nanostructured Cu processed by severe plastic deformation (SPD) is similar to 450 MPa, owing to the saturation of accumulated strain caused by recovery or recrystallization during the SPD process. The strength of SPD-processed Cu can be increased by adding solid-solution atoms. A significant increase in the strength of nanostructured Cu after adding a small amount of Si solute atoms was reported in our previous study. In this study, various-composition Cu-Zn, Cu-Si, and Cu-Ni solid-solution alloys were subjected to high-pressure torsion (HPT) processing, which is one of the SPD processes. To reveal the role of solid-solution atoms on the deformation of Cu during the SPD process, the effects of Zn, Si, and Ni additions on hardness and microstructure of Cu after various HPT rotations were systematically investigated, up to the solubility limits of these atoms. It is well known that Zn and Si atoms decrease the stacking fault energy (SFE) of Cu. On the other hand, Ni atoms have the opposite effect to that of Zn and Si on the SFE of Cu. Experimental results were considered in terms of the atomic concentration of solute atoms ca, electron-atom ratio e/a, and the SFE. The hardness of 140 HV of the nanostructured Cu significantly increased with increasing addition of Zn, Si, and Ni. The maximal hardness values of the nanostructured Cu-Zn, Cu-Si, and Cu-Ni alloys were 250 HV (29.4 at%Zn), 275 HV (4.5 at%Si), and 360 HV (81.4 at%Ni), respectively. In the case of the nanostructured Cu-Zn and Cu-Si alloys, the hardness increase correlated with the reduction in the SFE as a function of e/a. The decreased SFE by Zn and Si additions increased strain hardening during the SPD process. This strengthened the nanostructured Cu-Zn and Cu-Si alloys. On the other hand, hardening of the nanostructured Cu-Ni alloys is related not to the SFE changes, but to dislocation pinning or dragging by Ni solute atoms followed by suppression of recovery or recrystallization during the SPD process.
10.2320-matertrans.MH201323	-1		The changes in the mechanical properties on the inside and outside of the bend of Cu-0.3 mass% Sn wire specimens deformed by rotary draw bending were clarified, and the correlation between the changes in the misorientation of substructures and in the mechanical properties was systematically investigated. The specimens were each divided into two parts, i.e., the inside and outside of the bend, and their mechanical properties and microstructure evolution were measured by performing tensile tests. From the results, it was found that the ultimate tensile strength and 0.1% proof stress on the inside of the bend decreased markedly and that the total elongation was improved upon rotary draw bending. Although the tensile strength on the inside of the bend decreased, the change in grain size was very small. If rotary draw bending is performed on a wire specimen, it is considered that the dislocations generated by the tensile stress field are relaxed by the reversed stress induced during such bending.
10.2320-matertrans.MRA2007027	-1		A double cylindrical bicrystal is a bicrystal consisting of a cylindrical inside grain with a second g-rain wrapped around its curved side surface. Using a double cylindrical bicrystal of a Cu-SiO2 alloy, tensile tests were performed at 800 K under 2 x 10(-4) S-1. Three specimens cut from the same bicrystal were deformed to three different strains. Preferential formation of grain-boundary cracks around the cylindrical inside grain was observed after the tensile tests. In addition to the Occurrence of grain-boundary sliding, the misfit of slip deformation at the grain boundary affects the formation of the grain-boundary cracks.
10.2320-matertrans.MT-D2021001	6	grain; deformation; strain; strength; dislocation; cu-; tensile; size; ecap; grain size; sfe; ductility; hardening; high; stress	In our previous study, a thin wire of a Cu-0.29 mass%Zr alloy produced by repeated intermediate annealing during rolling and wire-drawing (IA wire) exhibited a 0.2% proof stress, sigma(0.2), of 600 MPa, an ultimate tensile strength, sigma(u), of 630 MPa, and an electrical conductivity, E, of 91.7%IACS. A thin wire of the alloy produced by ECAP-conform processing and subsequent rolling and wire-drawing (ECAP wire) showed larger values of sigma(0.2) = 730 MPa and sigma(u )= 790 MPa but a smaller value of E = 73.0%IACS than the IA wire. This study investigates the causes of the lower value of E and the higher value of sigma(0.2) of the ECAP wire, and the higher value of E of the IA wire. The higher value of sigma(0.2) of the ECAP wire is attributed to its smaller grain size and higher dislocation density. The lower value of E of the ECAP wire is primarily attributable to the fact that newly found, ordered face-centered cubic (fcc) precipitates having a cube-on-cube orientation relationship to the Cu matrix in the alloy produced by the ECAP-conform processing were cut by dislocations during rolling and wire drawing, resulting in dissolution in the Cu matrix. The IA wire showed the higher value of E because recrystallization by repeated intermediate annealing changed all the fcc precipitates into incoherent fcc precipitates that were not cut by dislocations. Further, based on the obtained results, an attempt was made to fabricate thin wires of the alloy having good strength, ductility and electrical conductivity. All the fcc precipitates in the alloy were made incoherent with the Cu matrix by utilizing recrystallization after sufficient precipitation. Then the alloy was processed by ECAP and subsequently wire-drawn. The fabricated thin wire exhibited higher values of sigma(u) = 820 MPa, epsilon(t) = 4.0% and E = 86.9%IACS.
10.2320-matertrans.MT-D2021002	6	grain; deformation; strain; strength; dislocation; cu-; tensile; size; ecap; grain size; sfe; ductility; hardening; high; stress	Microstructures and mechanical properties of Cu -Be -Co alloys having four different Be contents prepared by simply heavy cold rolling (CR) were systematically investigated. The cold-rolled alloys exhibited excellent mechanical properties due to development of heterogeneous nano-structure (HN), which consisted of eye-shape deformation twin domains surrounded by shear bands, and they were further embedded in conventional low-angle lamellae. The strength of each alloy increased with increasing Be content. The volume fraction of the twin domains quantitatively evaluated by the texture analyses that increased with increasing Be content rapidly from 0.40 mass% to 1.27 mass% and gradually from 1.27 mass% up to 2.14 mass%. The latter stagnation was attributed to the formation of coarse intermetallic particles, which impeded the formation of the HN structure. It revealed that the strength was correlated closely with the volume fraction of twin domains.
10.2320-matertrans.MT-D2021005	-1		In order to reveal the change in electrical resistivity and strengthening due to plastic deformation and microstructural evolution, investigation of mechanical and electrical properties was performed. From microstructural observations, it was found that the heterogeneous-nano structure having eye-shaped twin domains was formed of which volume fraction becomes largest at 90% of rolling reduction. Ultimate tensile strength increases with increasing rolling reduction and reaches about 735 MPa at 90% and 95% reductions. The electrical resistivity measured at 77K changes from about 39.6 n Omega m to about 61.9 n Omega m, and correspondingly, the conductivity at 293 K changed from about 28.0%IACS down to about 19.9%IACS. When compaering the total changes in electrical resistivity before and after reduction of 80%, the latter was larger. The more obvious changes in mechanical and electrical properties over reduction of 80% are associated with the formation of heterogeneous-nano structure in addition to increasing dislocation density.
10.2320-matertrans.MT-D2021006	-1		This study reports on an interfacial design method of Cu-SiC composites by means of nano-diamond/SiC composite particles in meltinfiltration process. In the case of Cu-SiC composites fabricated by melt-infiltration process, reaction layers consisting of spherical carbon particles and Cu-Si solid-solution alloys were observed as SiC particles reacted with melt Cu. Formation of reaction layers is not appropriate to obtain the predesigned characteristics such as physical and mechanical properties of the Cu-SiC composites. To overcome this problem, nanodiamonds, which were chemically inert with Cu, were bonded to the surfaces of SiC particles by amorphous silica as a bond material in order to shield the SiC particles from reacting with melt Cu. It was found that this shielding method enabled us to disperse SiC particles homogeneously in the Cu matrix without reaction layers. This interfacial design based on the composite particles should be expected to be applied to a promising mass production technology of metal-matrix composites (MMCs) due to its short processing time and large amount of production for processing composite particles.
10.2320-matertrans.MT-D2022005	-1		The effects of temperature and phosphorus addition on the surface tension of molten Cu -P alloys were measured by the oscillating droplet method using the electromagnetic levitation technique. We successfully measured the accurate surface tension of molten samples that were sufficiently above the liquidus temperature. The surface tension of liquid copper was determined in its pure state, which is free from any contamination, such as oxygen adsorption and chemical reaction with the supporting material. The surface tension of the molten sample was decreased as phosphorus addition was increased. The surface tension of molten Cu -P alloys was well expressed as functions of temperature and phosphorus activity from the measurement results using the Szyszkowski model. Furthermore, the enthalpy and entropy changes in phosphorus adsorption on liquid copper were also estimated.
10.2320-matertrans.MT-D2023002	-1		I n this study, high-entropy alloys ( H E A s ) with C u a s the main constituent element were investigated, focusing o n the distribution o f C u i n the ingots. Based o n the taxonomy o f H E A s, those with C u a s the casting material were classified a s (1) H E A s whose main constituent elements were 3 d transition metals, such a s C o, C r, F e, M n, N i, and C u (3 dH E A s ), and (2) high-entropy ( H E ) brasses based o n the C u-Z n alloy system and H E bronzes based o n C u-S n and/or Cu-Al alloy systems. I n the case o f 3 d-H E A s with C u, the distribution o f C u i n the ingots exhibited the following tendency: (1 -1 ) segregation from the dendrite t o the residual liquid, resulting i n the formation o f Cu-rich inter d e n d r i t i c regions i n the ingots; (1-2) liquid-phase separation resulting i n the formation o f a Cu-rich liquid, which formed a macroscopically phase-separated structure; and (1-3) the dispersion o f fine C u precipitates embedded i n the solid solution matrix.
10.2320-matertrans.MT-D2023007	6	grain; deformation; strain; strength; dislocation; cu-; tensile; size; ecap; grain size; sfe; ductility; hardening; high; stress	Wires of a Cu-3.8wt% Zr alloy were produced by conform extrusion followed by wire drawing up to 0.2 mm in diameter (S wire), or by conform extrusion and subsequent annealing during wire drawing up to 0.2 mm (IA wire). The effects of microstructure on the strength and electrical conductivity of the S and IA wires were investigated. The severely drawn S and IA wires had a mixed microstructure consisting of a Cu parent phase with fine grains, fibrous eutectics elongated along the drawing direction, and granular eutectics. The 0.2% proof stress (sigma(0.2)) and tensile strength (sigma(u)) of the S and IA wires increased monotonically with increasing drawing ratio (eta). The S wire with eta=7.8 exhibited large values of sigma(0.2)=1080 MPa and sigma(u)=1320 MPa. The S and IA wires having the mixed microstructure are strengthened primarily by high density of dislocations and grain refinement in the Cu phase and by the presence of fibrous and granular eutectics. The electrical conductivity (E) of the S wire increased in the early stage of wire drawing and then began to decrease, dropping to 42% IACS at eta=7.8. The increase in E is caused by refining of the eutectics, which was formed during casting, toward the granular or fibrous form. The E value of the IA wire after annealing was high, 72%IACS, and then decreased as eta increased. Values of E of the S and IA wires with the mixed microstructure was estimated by applying rules of mixtures. The estimated values of E are in agreement with the measured values of E. It is shown that the presence of the fibrous and granular eutectics significantly increases the electrical conductivity.
10.2320-matertrans.MT-D2023008	-1		Microstructural evolution and changes in hardness and electrical conductivities of a cast hypoeutectic Cu-2.7at%Zr alloy processed by high-pressure torsion (HPT) were investigated. The cast alloy had a net-like microstructure composed of a primary Cu phase and a eutectic consisting of layered Cu and Cu 5 Zr phases. The Cu and Cu 5 Zr phases in the eutectic had a cube-on-cube orientation relationship. The cast alloy with the hardness of 137 HV exhib ited a value of electrical conductivity of 32%IACS. With increasing the number of HPT-revolutions, the eutectic was severely sheared and elongated along the rotational direction. In addition, mechanical dissolution of the C u 5 Zr phase into the Cu phase by the HPT was confirmed after 5 HPT-revolutions through XRD measurements and TEM observations. After 20 HPT-revolutions, the Cu phase was significantly refined and formed the lamellar structure having an average grain size of 15 nm. The electrical conductivity decreased and saturated at a value of 8%IACS after 50 HPT-revolutions. The significant decrease in the electrical conductivity was primarily attributable to the mechanical dissolution of the C u 5 Zr phase into the Cu phase by the HPT, followed by the formation of a nanocrystalline Cu-Zr supersaturated solid-solution alloy with the h a r d n e s s o f 4 3 0 H V.
10.2320-matertrans.MT-D2023009	-1		The advancement of electronic devices and their capabilities has driven the demand for specific material property combinations, such as mechanical strength and electrical conductivity, in materials pertinent to device fabrication. To this end, the microstructure and properties of Cu-4.2 at% Ti alloy sheets, produced through a multi-step process involving over-aging and severe cold rolling, were investigated. The microstructure of the over-aged alloy prior to cold rolling consisted of cellular components with laminated plates of terminal copper solid solution (Cuss) and 6-Cu4Ti. When the over-aged alloy was severely cold rolled for a 99 % reduction in thickness, a hierarchical double-phase microstructure was formed parallel to the cold-rolling direction, with Cuss bands and two-phase bands containing small 6-Cu4Ti pieces stacked within Cuss phase. The strength of the over-aged alloy sheet increased steadily during increasing degrees of cold rolling, caused by a large volume fraction and fine dispersion of hard 6-Cu4Ti pieces and high dislocation density in the Cuss matrix. The electrical conductivity decreased in the later stages of cold rolling; however, the conductivity was higher than that of the alloy sheet prepared by peak aging and cold rolling. Eventually, the balance between strength and electrical conductivity of this Cu-Ti alloy was significantly improved by over-aging and severe cold rolling compared to conventional peak-aging and cold rolling processes.
10.2320-matertrans.MT-D2023012	6	grain; deformation; strain; strength; dislocation; cu-; tensile; size; ecap; grain size; sfe; ductility; hardening; high; stress	The dependence of mechanical twinning on the crystallographic orientation at the early stage of rolling was investigated. For this purpose, a copper-zinc alloy plate having a sharp {001} texture on the rolling plane (normal direction // (001)) was prepared, and the twinning behaviors during rolling were studied in the grains with orientations of rolling direction (RD) parallel to (100), (210) and (110). The precise examination revealed that grains with RD // (110) orientation were most prone to twinning among the three crystallographic orientations. Effects of the development of heterogeneous-nano (HN) structure on the tensile properties were also systematically investigated. As the rolling reduction increased from 50% to 70%, the tensile strength increased significantly, and the elongation to failure also increased simultaneously. Considering the microstructural changes, the increase in the strength/ductility balance was attributed to the formation of the HN structure. Further rolling up to 90% resulted in a slight increase in strength anda significant decrease in ductility to about half of the value at 70%. It was suggested that the decrease in the volume fraction of twin domains in the HN structure, instead increase in the other texture components, during the rolling reduction from 70% to 90% complicatedly spoiled the strength/ductility balance.
10.2320-matertrans.MT-D2024005	-1		The strength of a Cu-Ni-Si alloy can be improved by fi nely dispersing Ni-Si-based compounds as precipitates into the Cu matrix through heat treatment. This requires quantitatively evaluating the size distribution and dispersion state to investigate the strengthening effect of the precipitate. In this work, we utilized transmission electron microscopy, small-angle X-ray scattering (SAXS), small-angle neutron scattering (SANS), and atom probe tomography (APT) to analyze these Ni-Si precipitates. The APT results showed two types of diffusion layers at the interface between the Cu matrix and precipitates. The alloy contrast variation method was used to examine the difference in SAXS and SANS intensity in absolute units, which indicated that the delta Ni 2 Si precipitates are distorted.
10.2320-matertrans.MT-D2024007	6	grain; deformation; strain; strength; dislocation; cu-; tensile; size; ecap; grain size; sfe; ductility; hardening; high; stress	The hot-extruded bars of a Cu-Zn-Si alloy were subjected to groove rolling. Groove rolling was performed using rolls with grooves of different sizes so that the cross-sectional area of the bars after rolling decreased. The specimen bars were rotated by 90 degrees along the rolling direction after each rolling pass, and rolling was continued up to 68% reduction in cross-sectional area. With increasing rolling reduction, the initial coarse-equiaxed grains macroscopically elongated parallel to the rolling direction. Within the grains, ultra fine mechanical twins were high-densely introduced, which promptly and drastically fragmented the initial coarse grains to develop heterogeneous nano structure consisting of micro- and nano-meter-ordered mechanical twins. The tensile strength of the as-hot-extruded bar of 464 MPa increased to 704 MPa after 42% reduction, and further increased up to 940 MPa after 68% reduction. The remarkable increase in strength is attributed to the evolution of the heterogeneous nano structure developed by grain subdivision owing to dense mechanical twinning. It can be concluded, therefore, that the strength of the Cu-Zn-Si alloy bars was significantly increased by the evolution of the heterogeneous nano structure even by relatively small area reduction of 68%, i.e., equivalent strain of 1.13.
10.2320-matertrans.MT-D2024009	-1		A Cu/carbon steel multilayered sheet was quenched, and its tensile properties and electrical conductivity were evaluated. A full martensite structure was developed in the carbon steel layers in the multilayered sheet after quenching at 1063 K. The obtained Cu/martensite steel multilayered sheet exhibited a much higher ultimate tensile stress and approximately identical electrical conductivity compared to those in the Cu/carbon steel multilayered sheet without a quenching process. The decrease in the electrical conductivity during the quenching process in the multilayered sheet can be predicted from the decrease in the conductivity of the Cu layers owing to the diffusion of Fe atoms into the Cu layer. The ultimate tensile stress-electrical conductivity balance in the Cu/martensite steel multilayered sheet was 5.0 (c) 104 MPa%IACS, which is higher than that in conventional commercial Cu alloys. The ultimate tensile stress-total strain balance in the Cu/martensite steel multilayered sheet was significantly lower than that in each phase in the sheet. The measured ultimate tensile stress and electrical conductivity in the Cu/martensite steel multilayered sheet were approximately identical to the values estimated from the rule of mixture, using the tensile stress, electrical conductivity, and volume fraction of each component phase. This result indicates that the ultimate tensile stress and electrical conductivity of multilayered sheets can be easily controlled based on the rule of mixture.
10.2320-matertrans.MT-D2024015	-1		Pure copper and Cu-30 mass% Zn (Cu-Zn) alloy were subjected to tensile deformation at room temperature (approximately 298 K) and 573 K. Dislocation multiplication and motion during deformation were analyzed using neutron diffraction line-profile analysis. For the pure copper specimens, the dislocation density during deformation at 573 K was lower than that at room temperature. In contrast, the Cu-Zn alloys exhibited comparable levels of dislocation multiplication at both temperatures. Line-profile analysis revealed that the crystallites in the pure copper specimens became finer as the dislocation density increased, while the crystallite size of the Cu-Zn alloy specimens deformed at 573 K was considerably large and beyond the range that can be evaluated by the line-profile analysis. In the Cu-Zn alloys, although the dislocation density at 573 K was comparable to that at room temperature, the texture evolved by dislocation motion was weakened at 573 K, suggesting suppressed dislocation motion under these conditions. Transmission electron microscopy observations further demonstrated distinct dislocation substructures in the Cu-Zn alloys deformed at room temperature and 573 K. At room temperature, a Taylor lattice structure was observed, characterized by dislocations accumulating on planar slip planes. In contrast, at 573 K, dislocations were randomly distributed in a wavy form without forming tangles. This behavior suggests that the mobility of dislocations is reduced owing to interactions between solid solution elements and dislocations in the Cu-Zn alloys at 573 K. [doi:10.2320/matertrans.MT-D2024015]
10.2320-matertrans.MT-M2020045	-1		C6932 is a lead-free 75.5Cu-3Si-Zn alloy (hereinafter, C6932) which is excellent in machinability, strength, corrosion resistance, hot workability, and castability. C6932 is widely used for water-related products and in automobile and electricity fields, and over 40,000 tons of this alloy is distributed world-wide under the brand name of ECOBRASS (R). In the United States, a law to restrict lead in drinking water was put into force across the nation in 2014. Lead is going to be restricted in Europe also in the automobile field as well as electronic and electrical field. Considering this trend, more free-cutting copper alloys are likely to be free of lead. Concurrently, in the automobile field, for instance, there is a higher demand for improved fuel efficiency by reducing component weight and improved reliability by using components of higher strength . Based on these backgrounds, we have developed a lead-free, high-strength free-cutting copper alloy by optimizing the composition of a Cu-Si-Zn alloy and controlling its metallographic structure. The developed alloy shows significantly higher strength compared to C6932 without sacrificing its machinability and ductility. The alloy we have developed is a lead-free, high strength free-cutting copper alloy with tensile strength of 650 MPa and an elongation of 43%, which can be realized by annealing a 76.3Cu-3.2Si-0.2Sn-Zn alloy and controlling the grain size to 8 mu m.
10.2320-matertrans.MT-M2020049	-1		Face-centered cubic Co-free Cu-containing solid solution concentrated alloys, Cu, CuNi, CuNiFe, Cu0.3NiFeCr, Al0.4CuFeCrNi2 were prepared, and their microstructure, hardness, and tensile strengths were investigated in order to develop a new high entropy alloy with a high irradiation resistance, which is applicable for nuclear reactor components. All the as-cast alloys were identified as single-phase FCC alloys by X-ray diffraction analysis. While, the SEM observation indicated a new Cr-rich phase with Cu-rich phase in the annealed Cu0.3NiFeCr alloy, which is probably due to low solubility of Cr and Cu in the alloy. After annealing at 1076 degrees C for 120 hours, Cu0.3NiFeCr alloy became a single-phase FCC. Mechanical property examinations indicated the highest Vickers hardness, the highest Tensile strength and the smallest elongation in the Al0.4CuFeCrNi2. The results indicate that the Al0.4CuFeCrNi2 alloy would have the potential to be a Co-free high-entropy alloy applicable to nuclear reactor components. In order to improve the elongation of Al0.4CuFeCrNi2, the detailed analysis of fracture surface and the optimization of annealing condition would be needed.
10.2320-matertrans.MT-M2020149	-1		Herein, the isothermal aging behavior of copper-titanium-magnesium (Cu-Ti-Mg) supersaturated solid-solution alloys, with different compositions, under test conditions of 450 degrees C for 100 h, has been thoroughly investigated in a comparative study using various electron microscopy and microanalytical techniques. The Vickers hardness and electrical conductivity of the ternary alloys were recorded at slightly elevated (during aging) and reduced levels than their binary counterparts without Mg doping. Hence, it is proposed that the hardness and conductivity values are approximated from the superposition effect of precipitation hardening stimulated by Ti solutes and solution hardening by both Ti and Mg solutes. Furthermore, the tensile tests for these ternary specimens have demonstrated that Mg doping has a substantial effect on the improvement of the tensile strength and fracture elongation properties of binary Cu-Ti alloys. Aberration-corrected high-angle annular dark-field scanning transmission electron microscopy imaging combined with atomic-resolution energy-dispersive X-ray spectroscopy mapping analysis confirmed that the same metastable precipitate phase is responsible for peak hardening in ternary and Cu-Ti binary alloys. In addition, a large part of the Mg solutes is homogeneously distributed over the matrix regions, while there is also a smaller part of those present in the precipitates. The potential effects of Mg doping on the microstructures of Cu-Ti alloys were elucidated and the structural environment, which may yield relatively high mechanical properties, was discussed using the aforementioned observations.
10.2320-matertrans.MT-M2020308	6	grain; deformation; strain; strength; dislocation; cu-; tensile; size; ecap; grain size; sfe; ductility; hardening; high; stress	Tensile deformation behavior of high-strength nanostructured Cu-Si solid-solution alloys processed by high-pressure torsion (HPT) with 5 rotations was investigated at room and low temperatures. With increasing Si concentration, tensile strength of the nanostructured Cu-Si solid-solution alloys was significantly increased. The maximal tensile strengths were 980 MPa at room temperature, and 1350MPa at 77K in a Cu-2.04 wt%Si alloy. This significant strengthening was achieved by grain refinement and increased dislocation density through severe plastic deformation (SPD) with the effect of Si addition on the decreasing stacking fault energy of the Cu-Si alloy. With increasing Si concentration, strain-rate sensitivity m of the nanostructured Cu-Si solid-solution alloys was decreased due to the increased dislocation density, resulting in accelerating plastic instability of tensile specimens, caused by the diminishing strain-rate hardening capacity after necking.
10.2320-matertrans.MT-M2020367	6	grain; deformation; strain; strength; dislocation; cu-; tensile; size; ecap; grain size; sfe; ductility; hardening; high; stress	In our previous study, a thin wire of a Cu-0.29 mass%Zr alloy was produced by annealing after rolling and two subsequent intermediate annealing steps during wire drawing (IA wire). The produced IA wire had an ultimate tensile strength, sigma(u), of 610 MPa and a small total elongation, epsilon(t), of 1.2% despite a small grain size, D, of 240 nm. In this study, a thin wire of the same alloy was produced by annealing after rolling and subsequent wire drawing (S wire). Even though the S wire had almost the same values of sigma(u) = 620 MPa and D = 230nm as the IA wire, the S wire exhibited a larger epsilon(t) = 2.9%. This study investigated the cause of this smaller value of epsilon(t) for the IA wire. In both the IA and S wires, voids were formed by decohesion of the interface between the Cu matrix and particles consisting of a eutectic (Cu + Cu5Zr) during wire drawing; however, the fraction of eutectic particles with voids was larger in the IA wire than the S wire. The IA wire exhibited lower ductility as a result of easier coalescence of the voids during tensile testing. In addition, the larger fraction of eutectic particles with voids in the IA wire is attributed to the larger size of recrystallized grains generated by the intermediate annealing during wire drawing than that of the grains before intermediate annealing. As a result, dislocations accumulated significantly around the eutectic particles during the subsequent wire drawing, resulting in a high stress concentration.
10.2320-matertrans.MT-M2021237	-1		Copper (Cu) alloy thin films deposited on barrierless substrates via sputtering and annealing processes have been essential for numerous microelectronic products and continue to be so in the new nanometer-range manufacture era. The search for better new films thus is crucial for further technical and manufacture advancement. The requirements on the new films lie in their stability in existence under high-temperature manufacture environments, low electric resistivity, less leakage current under various electric fields, and sufficient adhesion strength . For the search and advancement, I have developed a new type of films by co-sputtering impurities of niobium, Nb, and zirconium, Zr, with Cu within a vacuum chamber without any gas or with nitrogen (N) under low pressure, resulting in new Cu(NbZr) or Cu(NbZrNx) films whose fabrication processes and test results are detailed herein. The new type of films displays good physical features and seems desirable for microelectronic manufacture and to material science, too.
10.2320-matertrans.MT-M2023136	3	sma; shape; shape memory; memory; smas; superelastic; bars; damping; cu-al-mn; mechanical; bending; applications; numerical; sma bars; material	In recent years, Hard Cyclic Viscoplastic Deformation has become a new effective SPD method for studying the evolution of the structure and properties of Cu -alloys without changing the dimensions of the workpieces up to their destruction during processing at room temperature. Linear compression -tension of the material in the viscoplastic region is carried out in the strain control mode in the range from 3/4 = +/- 0.2% to +/- 3% at a constant frequency off = 0.5 to 2 Hz with a total number of 20-40 cycles in each test series. This method can be used also to improve and stabilize the ultrafine grained microstructure, and also allows you to study changes in the mechanical, physical and functional properties of coarse grained, ultrafine grained, and nanocrystalline metallic materials. Can also to be used to study the stability and viability of metallic materials and predict their suitability over time in harsh environments such as space and military applications. [doi:10.2320/matertrans.MT-M2023136]
10.2320-matertrans.MT-M2024114	0	solidification; phase; magnetic; magnetic field; undercooling; field; liquid; separation; peritectic; immiscible; cu-; dendrite; phase separation; microstructure; primary	A secondary liquid phase with a droplet shape is separated from the primary liquid phase in Cu-Ni-Fe-Mo-Si alloy during laser cladding processing. During the subsequent quenching process, the secondary liquid phase solidifies into hard particles that are dispersed in the primary matrix phase. An increase in Ni content suppresses coarsening of the hard particles, while the mechanism of the suppression has not been clarified. In this study, we investigated the effect of Ni content on hard particle size, mainly emphasizing the Marangoni effect controlled by the temperature dependence of interfacial energy. The effects on the hard particle size were analyzed based on changes in the starting temperature of the separation of two liquid phases (L1 and L2) and the temperature dependence of interfacial energy, calculated for various Ni contents using CALPHAD software. Our fi ndings revealed that the Ni content had little effect on the temperature dependence of interfacial energy. However, an increase in the Ni content decreases the temperature of L2 droplet formation and shortens the time to solidification, thereby reducing a moving distance of droplet. Therefore, the collision frequency of L2 droplets caused by the Marangoni effect was reduced, and coarsening of the droplet was suppressed.
10.2320-matertrans.MT-MBW2019005	-1		Oxide Dispersion Strengthening copper (ODS-Cu) alloy has high strength, high thermal conductivity and superior irradiation resistance which are needed for fusion reactor divertor components. In this study, specimen size dependence of the yield stress in Cu and ODS-Cu which were made by mechanical alloying and hot pressing was investigated by micro-pillar compression test. The distributions of yield stress values were different between the sizes, 1, 3 and 5 mu m cubic micro-pillars, which can be explained by the inhomogeneous spatial distributions of both the crystallographic grain in matrix and oxide-particles.
10.2320-matertrans.MT-MF2022046	-1		In recent years, the severe plastic deformation community has developed an interest for metallic materials with high strength and high electrical conductivity, with special focus in Cu- and Al-based alloys, including composite materials. Several processing and metallurgical strategies have been applied to control the influence of microstructure features such as grain refinement, grain boundary condition, defect structures and segregation of secondary phases, over the electrical and mechanical properties. This work summarizes an important body of literature where several strengthening mechanisms and methods to restore the electrical conductivity have been applied to produce ultrafine-grained or nanostructured Cu and Al alloys, mainly by intense imposed strain. A wide variety of alloy systems were studied for their industrial applications in the electrical and electronic market. It can be concluded that the balanced combination of alloying element selection and processing route (mainly attainable under high hydrostatic conditions) could provide high strength with high conductivity and thermal stability materials.
10.2320-matertrans1989.41.238	-1		Diffuse scattering associated with a short-range ordered (SRO) state in a Cu-27.5 at%Pd alloy was quantitatively analyzed using energy-filtered transmission electron microscopy. By subtracting the background in electron diffraction with the energy hirer, diffuse scattering splitting in two and fourfold was clearly observed at around 100, 110 and their equivalent positions in reciprocal space. Through the analysis of the electron diffraction patterns, it was clarified that the intensity distributions of the diffuse scattering did nor change considerably will the crystal thickness, while those of the fundamental reflections remarkably changed. The intensity ratio of the total diffuse scattering to the total electron intensity increased monotonously with the increase of the crystal thickness, Based on these results, the two-dimensional SRO parameters of this alloy were quantitatively evaluated from the energy-filtered electron diffraction patterns.
10.2351-1.5127559	-1		The crystallographic texture, thermal conductivity, and microhardness of the Cu-2.4Ni-0.7Si alloy processed by selective laser melting (SLM) were investigated. The SLM sample shows columnar grains with stronger (100) preferred orientation, and the content of high-angle grain boundaries (HAGBs) is 64.6%. It owns the lower microhardness of 89.73 HV and the higher thermal conductivity of 187.83 W/m K. After heat treatment for 12 and 25 h, the microstructure of the samples changes from the coarser columnar grains to the smaller equiaxedlike grains with the HAGBs of 59.6% and 61.8%, which show (100), (101), and (111) orientations equally then exhibit stronger (101) and (111) preferred orientation. Moreover, the precipitates vary from Ni3Si with a size of 0.5 mu m to Ni2Si with a size of 1 mu m, hence resulting in higher microhardness of 180.02 and 170.03 HV. Due to the precipitates, lower texture index and HAGBs' content that generate the more grain boundary scattering for electron and phonon transport lead to lower thermal conductivity of 161.57 and 177.83 W/m K. This study suggests that thermal conductivity and microhardness of the SLM Cu-Ni-Si alloy can be tailored by controlling suitable heat treatment condition.
10.2351-7.0000464	-1		Over the last several decades, additive manufacturing (AM) has been primarily used for rapid prototyping or to create novel geometries that would be difficult or impossible to create by normal manufacturing methods. More recently, research has been focused on expanding the list of materials that can be made through additive manufacturing, opening a greater range of material properties for this manufacturing method. Due to the unusual conditions during AM, including the high cooling rates and voxel by voxel method of production, AM parts often have anisotropic material microstructures and properties. In this investigation, the laser power, composition, and nozzle head speed during direct metal deposition of copper-iron alloys was varied to understand how the grain structure within the printed parts could be changed and controlled. The resulting dendrite spacing was measured and compared to calculated cooling rates from Gaussian beams on flat plates under similar material and laser properties, which resulted in a cooling rate to dendrite spacing relationship following an inverse square root, as is found in other dendritic systems [Young and Kerkwood, Metall. Trans. A 6, 197-205 (1975)]. Thus, it is demonstrated that in the Cu-Fe system, dendrite spacing can be controlled through manipulation of printing parameters. (c) 2022 Author(s).
10.2355-isijinternational.45.183	-1		A two-dimensional computational model, coupling a hmacroscopic heat and fluid flow analysis with a cellular automaton model under electromagnetic stirring, was developed. The dynamic evolution of solidification grain structures and transport phenomena during solidification were presented successfully. The Gaussian distribution was chosen to deal with nucleation events both on the mold wall and in the bulk melt. The KGT (Kurz-Giovanola-Trivedi) model, based on the calculated temperature field, was adopted to evaluate the growth velocity of a dendrite tip. The material used was an Al-5.0wt%Cu alloy. Both the computational and experimental results showed that grain refinement was improved remarkably with electromagnetic stirring. The fully equiaxed grain structures were obtained with a proper choosing of the casting process variables, such as pouring temperature, cooling rate and stirring intensity.
10.2355-isijinternational.51.1819	0	solidification; phase; magnetic; magnetic field; undercooling; field; liquid; separation; peritectic; immiscible; cu-; dendrite; phase separation; microstructure; primary	Cu-11 mass% Fe alloy samples were solidified with and without a high magnetic field. The influence of a high magnetic field and cooling rate on the morphology, alignment and distribution of primarily precipitated Fe-rich phase has been investigated. We found that the primary phase of Fe-rich was equiaxed dendrites or columnar dendrites under the combinations effect of magnetic field and initial cooling rate. And Fe-rich primary phase with random alignment was mainly observed in the upper region of the sample solidified without the magnetic field. In the case of the sample solidified with the magnetic field of 7.5 T, however, Fe-rich phase was uniformly distributed and the Fe-rich phase at some areas was aligned parallel to the direction of the magnetic field. Furthermore, slower cooling rate was beneficial to the alignment but was not to the uniform distribution. These phenomena were well discussed from the viewpoint of magnetic shape anisotropy and convection under the high magnetic field.
10.2355-isijinternational.ISIJINT-2017-233	-1		In this paper, the effect of super-gravity field on the grain refinement and tensile properties of as-cast Cu-Sn alloys were investigated systematically. The experimental results revealed that the as-cast grains of Cu-Sn alloys can be significantly refined in super-gravity field. In normal gravity field, the average grain size is 2.13 mm, while in super-gravity fields of G=100, 300 and 600, they are 0.35 mm, 0.173 mm and 0.074 mm, respectively. Accordingly, both the tensile strength and the plasticity are enhanced with the increasing gravity coefficient. The ultimate tensile strength of Cu-11wt%Sn sample in normal gravity field is 265 MPa, while in super-gravity fields of G=100, 300 and 600, they are 449 MPa, 487 MPa and 521 MPa, respectively. The fracture morphology transforms from fragility to plasticity with the increasing gravity coefficient. The mechanism for the grain refinement is that super-gravity promotes the falling of crystal nuclei within the solidifying melt only at the early solidification period, which can be called the Crystal Rain. As a result, the crystal nuclei multiply within the solidifying melt and a refined grain structure was obtained. Besides, the refining effect by super-gravity increases with the increasing solute Sn concentration because of the increased nucleation rates and a decrease in crystal growth .
10.2355-isijinternational.ISIJINT-2017-557	0	solidification; phase; magnetic; magnetic field; undercooling; field; liquid; separation; peritectic; immiscible; cu-; dendrite; phase separation; microstructure; primary	Directional solidification experiments on Cu-20 wt% Sn peritectic alloy were carried out in a direct current magnetic field device to investigate the modification of the primary and peritectic phases. A precipitation of the acicular martensitic structure of peritectic phase was observed below the solid-liquid interface. The magnetic field increased the length of precipitation zone and moved the solid-liquid interface to high temperature side. Solid-state transformation of the peritectic phase was observed below the eutectoid temperature. The magnetic field increased first and then decreased the transformation. A transition of the primary dendrites from arrayed to nonaligned growth under the magnetic field was characterized and analyzed. 3D numerical simulations of the thermoelectric magnetic flows and the thermoelectric magnetic forces were performed. The modification of the primary and peritectic phases under the magnetic field should be attributed to the fluid flows in the liquid and the forces on the solid.
10.2355-isijinternational.ISIJINT-2023-295	-1		The ancient copper smelting was simulated to produce molten Cu-Fe alloys without Fe lump from Chile copper ore powder and limonite powder at 1 300 to 1 350 degrees C. Using the same furnaces and the same conditions of operation for copper smelting, the ancient ironmaking was performed to produce molten Fe-C alloy. The atmosphere in the furnaces was controlled by the redox reaction of Fe and FeO. For the copper smelting, the oxygen partial pressure was higher than the equilibrium value of Fe and FeO, and for the ironmaking it was lower than the equilibrium value. From these aspects, the technical continuity from ancient copper smelting to ironmaking was clarified.
10.24425-118950	16	wear; composite; composites; powders; milling; particles; powder; wt; sliding; friction; hardness; matrix; mechanical; surface; properties	In this study, the powder mixture which consists of Cu-Fe-Co was produced by using the method of hot pressing technique. In addition, effect of heat treatment process on microstructure and mechanical properties of this alloy was investigated. Following the hot pressing process applied on the samples, heat treatment was carried out at 950 degrees C for two different dwelling times (90 and 180 minutes). Measured density values were considered as physical characteristics, while hardness and fracture strength values were considered as mechanical characteristics. It was observed that porosity rates of hot pressed samples were decreased by increasing of temperature and pressing parameters. In this study it was observed that Cu was spread in matrix and filled the micro porosities. Hardness values were determined to be decreased as a result of grain growth after heat treatment process. That 4 fold increased elongation % values which were achieved by TRS experiments were observed as well.
10.24425-amm.2018.125082	4	transformation; martensite; martensitic; phase; shape; beta; memory; shape memory; temperature; temperatures; martensitic transformation; gamma; transformation temperatures; effect; thermal	Cu-Al-based high temperature shape memory alloys are preferred commonly due to their cheap costs and shape memory properties. In recent years, studies have been conducted on developing and producing a new type of Cu-Al based shape memory alloy. In this study, the CuAl-Cr alloy system, which has never been produced before, is investigated. After production, the SEMEDX measurements were made in order to determine the phases in the Cu84-xAl12Crx+4 (x = 0, 4, 6) (weight %) alloy system; and precipitate phases together with martensite phases were detected in the alloys. The confirmations of these phases were made via x-ray measurements. The same phases were observed by XRD diffractogram of the alloys as well. The values of transformation temperature of alloys were determined with Differential Scanning Calorimetry (DSC) at 20 degrees C/min heating rate. According to the DSC results, the transformation temperature of the alloys varies between 320 degrees C and 350 degrees C. This reveals that the alloys show high temperature shape memory characteristics.
10.24425-amm.2019.129468	-1		Cu-Ni composite nanoparticles were successfully synthesized by electrical explosion of wire (EEW) method. Cu-Ni alloy and twisted wires with various Ni contents were used as the feeding material for a 3 kV charging voltage EEW machine in an ethanol ambient chamber. The phase structure and magnetic properties of the as-fabricated samples were studied. It was established that the prepared powders after drying have a spherical form with the particle size is under 100 mu. XRD analysis indicated that the nanopowders consisted of binary Cu-Ni phases. Only pure phases of the intermetallic compound Cu-Ni (Cu0.81Ni0.19 and Cu3.8Ni) were observed in the XRD patterns of the samples. The synthesized intemietallic Cu-Ni alloy nanopowders reveal magnetic behaviors, however, the lower Ni content samples exhibited paramagnetic behaviors, meanwhile, the higher Ni content samples exposed ferromagnetic properties.
10.24425-amm.2020.132794	16	wear; composite; composites; powders; milling; particles; powder; wt; sliding; friction; hardness; matrix; mechanical; surface; properties	Friction Stir Process (FSP) was employed to develop Cupro-Nickel/Zirconium Carbide (Cu-NiarC) surface composites. Five different groove widths ranging from 0 to 1.4 mm were made in CuNi alloy plate to incorporate different ZrC volume fraction (0, 6, 12, 18 and 24 %) to study its influence on the structure and properties of Cu-Ni/ZrC composite. Processing was performed at a Tool Rotational Speed (TRS) of 1300 rpm, Tool Traverse Speed (TTS) of 40 mm/min with a constant axial load of 6 KN. The study is performed to analyse the influence of ZrC particles and the volume fraction of ZrC particles on the microstructural evolution, microhardness, mechanical properties, and tribological characteristics of the Cu-Ni/ZrC composite. The fracture and worn-out surfaces are analysed using Field Emission Scanning Electron Microscope (FESEM) to identify the fracture and wear mechanisms. The results demonstrated a simultaneous increase in microhardness and tensile strength of the developed composite because of grain refinement, uniform dispersion, and excellent bonding of ZrC with the matrix. Besides, the wear resistance increases with increase in volume fraction of ZrC particles in the composite. The surface morphology analysis revealed that the wear mechanism transits from severe wear regime to mild wear regime with increase in volume fraction of ZrC particles.
10.24425-amm.2020.132803	2	corrosion; surface; film; electrochemical; films; spectroscopy; layer; current; solution; potential; resistance; composition; x-ray; ions; showed	Evaluation of inorganic and organic compounds as corrosion inhibitors of Cu-Zn alloys in H2SO4 and HNO3 solutions was studied using potentiodynamic and impedance spectroscopy along with scanning electron microscope (SEM) and energy dispersive X-Ray analyzer (EDX) investigations. The corrosion inhibition of Cu-Zn alloys was investigated in oxy acid solutions using inorganic potassium permanganate and di-hydrogen phosphate, amino acids as environmentally safe materials, commercial cooling water, and green tea extracts. Both potassium permanganate and di-hydrogen phosphate improve the corrosion resistance of Cu-Zn alloys. Phosphate appears more effective as corrosion inhibitor for Cu-Zn alloys than permanganate. The inhibition efficiency (IE%) of the different amino acids such as valine, leucine and lysine was also calculated. The experimental results have shown that amino acid-like lysine can be used as an efficient corrosion inhibitor for the Cu-Zn alloys in oxy acid solutions. This may be due to the presence of two amino groups adsorbed together. For lysine, inhibition efficiency, IE%, of similar to 87 and similar to 59 is for H(2)SO(4 )and similar to 96.3 and 54.9 for HNO3 for alloy I and II respectively are observed. Due to the composition of green water have a great effect on the inhibition action on Cu-Zn alloys which reaching 91.8 and 96.5% for Alloy I and 95.4 and 87.1% for Alloy II in 0.5 M H(2)SO(4 )and HNO3 respectively. Although benzotriazole, in cooling water, is an excellent inhibitor suitable for use in a wide variety of environments, it has toxic properties. So, much of the recent researches have focused on formulating new and more environmentally acceptable preservation solutions. The green tea, as plant extract, will be very environmentally friendly. The EDX confirm the formation of a protective layer on the Cu-Zn alloys containing aluminum in Alloy II. This sequence reflects the beneficial effects of Al in Alloy EL The presence of 2.43% Al in Alloy II improves the corrosion resistance due to the formation of thin, transparent, stable and self- healing Al(2)O(3 )layer. This confirmed the results obtained from the potentiodynamic polarization measurements and EIS methods.
10.24425-amm.2021.134766	-1		Cu-2wt%Ag alloy with diameter of 10 mm was fabricated by induction heating directional solidification (IHDS). The effect of different mold temperatures on microstructure of IHDS Cu-2wt%Ag alloy was investigated. The results show that IHDS Cu-2wt%Ag alloy is mainly composed of coarse columnar grains at mold temperature of 1075 degrees C. While the mold temperature is at 1100 degrees C, 1150 degrees C and 1200 degrees C, respectively, the IHDS Cu-2wt%Ag alloy is composed of columnar grains and equiaxed grains and the number of grains increases. Meanwhile, the growth direction of columnar grains in the edge of alloys deviates from the direction of continuous casting to form V shape. While the mold temperature is controlled at high temperature, the induced current increases, which leads to the enhancement of eddy current in the mold. Therefore, the dendrites fall off to form new grains under the effect of eddy stirring, resulting in an increasing in the number of grains.
10.24425-amm.2021.134772	-1		The study investigates the effect of heat treatment on the microstructure evolution and properties of an age-hardened Cu-3Ti-2Mg alloy. The precipitated Cu2Mg and beta'-Cu4Ti phases consequently yield a depletion of the Cu matrix in regards to Ti and Mg solutes, which enhances the electrical conductivity. The Cu2Mg Laves phase and beta'-Cu4Ti phase precipitates increase the hardness of the alloy due to the consistency and coherency of the later phase. However, the decrease of hardness is mainly associated with the coarse microstructures, that can be formed due to the phase transformation from metastable beta'-Cu4Ti phase to more stable Cu3Ti phase. In the range of experiments, the optimum process is solution treatment at 700 degrees C for 4 h, with subsequent age-hardening at 450 degrees C for 4 h . The electrical conductivity, hardness, tensile strength, and elongation of the Cu-3Ti-2Mg alloy were 15.34 %IACS, 344 HV, 533 MPa, and 12%, respectively.
10.24425-amm.2022.141072	-1		In this study, the nominal composition of Cu-2.5Ti alloy was thermally treated to obtain homogenized, aged, and 40% prior cold-rolled+ aged samples. The hardness, wear behavior, and microstructure of samples were investigated. The reciprocating wear tests were performed under four different loads under dry and 3.5%NaCl corrosive environments. The alloy reached its highest hardness value of 8 hours for the aged sample. The hardness value of the sample that was homogenized then cold-rolled by 40% and aged was found higher than the other samples. A decrease in the wear rates in dry conditions was observed in homogenized, aged and cold-rolled and aged samples, respectively. This decrease was more in the corrosive environment. Studies can be advanced by examining the wear behavior at different alloy ratios. The effects of different alloying elements and the ratio of cold-rolled before or after aging can also be investigated for future research .
10.24425-amm.2022.141077	16	wear; composite; composites; powders; milling; particles; powder; wt; sliding; friction; hardness; matrix; mechanical; surface; properties	This work mainly focuses on the sintering behavior of the Cu-Sn alloy with the addition of Ag up to 4 wt% after pulsed electric current sintering (PECS) process for ultra-fast sintering. The microstructural evolution was characterized using scanning electron microscopy (SEM), X-ray diffraction (XRD), and density measurements. The mechanical properties were evaluated via measurements of transverse rupture strength (TRS) and Rockwell hardness. The mechanism during the sintering process has been discussed thoroughly, and the effect on porosity with the addition of the Ag is also correlated. The results showed that the growth of porosity progressed with the amount of Ag up to 2 wt%, and further addition of Ag leads reduction in porosity. The effect on mechanical properties were improved slowly as the amount of Ag increased.
10.24425-amm.2023.141474	-1		Cu-Sn alloys have been known as bronze since ancient times and widely used as electrode materials, ornaments, tableware and musical instruments. Cu-22Sn alloy fabrication by hot forging process is a Korean traditional forged high-tin bronze. The tin content is 22 percent, which is more than twice that of bronze ware traditionally used in China and the West. Copper and tin have a carbon solubility of several ppm at room temperature, making Cu-Sn-C alloys difficult to manufacture by conventional casting methods. Research on the production of carbon-added copper alloys has used a manufacturing method that is different from the conventional casting method. In this study, Cu-22Sn-xC alloy was fabricated by mechanical alloying and spark plasma sintering. The carbon solubility was confirmed in Cu-Sn alloy through mechanical alloying. The lattice parameter increased from A0 to C2, and then decreased from C4. The microstructural characteristics of sintered alloys were determined using X-ray diffraction and microscopic analysis. As a result of comparing the hardness of Cu-22Sn alloys manufactured by conventional rolling, casting, and forging and Cu-22Sn-xC alloy by sintered powder metallugy, B0 sintered alloy was the highest at about 110.9 HRB.
10.24425-amm.2023.146204	15	aging; strength; conductivity; electrical conductivity; electrical; mpa; treatment; strengthening; degrees; cu-; cold; precipitation; tensile strength; tensile; iacs	The phase transformation dynamic and electrical conductivity equations of the aged Cu-2.7Ti-2.5Ni-0.8V alloy were established in this work. The microstructure evolution and precipitated phases were characterized by scanning electron microscopy (SEM) and transmission electron microscopy (TEM). The mechanical properties were tested using a hardness testing machine and universal test machine, and the electrical conductivity was measured by the eddy conductivity gauge. The results show that NiTi intermetallic compounds are formed during the solidification, and these phases such as Ni3Ti and NiV3 are precipitated after aging treatment. The fracture morphology displays that a large number of shallow and equiaxed dimples occur on the tensile fracture, indicating a typical ductile fracture. After aging treatment at 450 degrees C for 240 min, the hardness, tensile strength, elongation and electrical conductivity of the Cu-2.7Ti-2.5Ni-0.8V alloy are 184 HV, 459 MPa, 6.3% and 28.72% IACS, respectively.
10.24425-amm.2024.147776	6	grain; deformation; strain; strength; dislocation; cu-; tensile; size; ecap; grain size; sfe; ductility; hardening; high; stress	A Cu-1Cr-0.1Zr alloy has been subjected to ECAP processing via route Bc and aging at 250-800 degrees C. Electron BackScatter have been used to unveil some peculiarities of the grain and subgrain structure with a special emphasis on the comparison of the grain size estimated by the three techniques. For the alloy ECAP processed and aged up to 16 passes, the grain size (from EBSD, 0.2 < d < 5 gm), subgrain size (from TEM, d similar to 0.75 gm) and apparent average crystallite size (from XRDLPA, d < 0.25 gm) are manifestly different. The results were compared to the published data and analyzed based on the fundamental aspects of these techniques.
10.24425-amm.2025.152550	-1		In this work, the microstructure and recrystallization behavior of Cu-3Ti-3Ni-0.5Si alloy after thermomechanical processing were investigated by light microscope (LM), scanning electron microscope (SEM), electron backscattering diffraction (EBSD), and transmission electron microscope (TEM). The results show that the as-cast Cu-3Ti-3Ni-0.5Si alloy consists of NiTi, Ni3Si, Ni2Si phases and Cu matrix, and the phase transformation occurs twice during the cooling process. Moreover, with increase of aging temperature, the precipitates in the Cu-3Ti-3Ni-0.5Si alloy matrix changes from rod-liked morphology to spherical shape, and the sizes and volume fraction of the spherical precipitates increase progressively. Furthermore, the number of the recrystallization grain increases with increase of the aging temperature, thus leading to decrease on the grain size. In addition, the fraction of low angle grain boundaries decreases, whereas the fraction of high angle grain boundary increases with increase of aging temperature.
10.2478-amm-2014-0061	-1		The paper presents results of the studies into influence of individual particles of lubricating phase on microstructure and tribological properties of copper based composite materials for slide bearings. The studied material was composed of copper alloys with lubricating phase particles, e. g. in a form of graphite and glassy carbon. The metallic matrix of composite materials consisted of Cu-Sn type alloys. Production of the examined materials included processes with complete or partial participation of liquid phase and was conducted in two ways. In production of composites both classical powder metallurgy technology was applied and a method of melting with simultaneous mechanical stirring in liquid state (stir casting). Particles of lubricating phases were heated up to the temperature of 200 degrees C and introduced into a liquid metal and then stirring process at constant rate of 1500 rpm rotational speed was applied. To improve wettability of graphite and glassy carbon particles titanium was introduced into the metallic matrix. In production of the composites by powder metallurgy methods the process consisted of mixing of bronze powders and particles of non-metallic phases and then their consolidation. Both quantitative and qualitative structure analysis of the produced composites was performed. Also through evaluation of tribological properties (friction coefficient, wear) with CSM Instruments high temperature tribometer THT was conducted.
10.2478-amm-2014-0101	-1		The results of research into influence of chemical composition on structure and tribological properties of copper-based composites intended for slide bearings are presented in this paper. The study was focused on copper alloys with lubricating phase particles in form of graphite, tungsten disulphide (WS2), molybdenum disulphide (MoS2) and glassy carbon. The metallic matrix of composite materials was composed of alloys from Cu-Sn-Zn system. The mass content of lubricating phase particles was from 5 to 20%. The process of production of subject materials included the processes conducted with full or partial contribution of liquid phase and it was conducted by two methods. Both the method of classic powder metallurgy and stir casting method were used for the production of composites. Lubricating phase particles heated to the temperature of 200 degrees C were introduced to liquid metal bath and then the process of stirring and casting to moulds was performed. In case of production of composites by powder metallurgy, the process included mixing of bronze powders and lubricating phase particles, and then their consolidation. Sintering process was conducted in temperature between 750 divided by 800 degrees C. The produced materials were tested in terms of microstructure and tribological properties with the CSM Instruments tribometer.
10.2478-msp-2022-0051	-1		This article is devoted to research of the tribosynthesis mechanism of antifriction films and their influence on the functional properties of antifriction composites based on copper alloyed with nickel and molybdenum with the CaF2 solid lubricant additions for operation at rotation speeds of 3,000-7,000 rph and increased loads of 3.0-5.0 MPa in air. Studies have shown that antifriction films are complex, dynamically changing formations on the surfaces of the composite and counterface, developing according to the bifurcation mechanism. The antifriction layer is decisive in the formation of the friction pair's tribological high-level properties, which provide the self-lubrication mode of the friction unit. The formation and permanent presence of the anti-seize film is associated with a balanced wear rate of the film and its constant formation again on these worn areas at rotation speeds of up to 7,000 rph and loads of up to 5.0 MPa. Due to the steady self-lubrication mechanism, the copper-based composite has significant advantages over cast bronze CuSn5ZnPb, which can only work with liquid lubrication in the friction units of printing machines. The performed studies make it possible to choose rational modes for operation of new high-speed antifriction Cu-composites based on the friction films analysis, predicting their high functional properties.
10.2478-msp-2023-0017	-1		The aim of this study is to explore the structural and optoelectronic properties of Cu-Cr-O thin films when processed by the magnetron sputtering method using a single equimolar CuCr alloy target. These films were then post-annealed in a controlled Ar atmosphere at 500 degrees C to 800 degrees C for 2 h . The as-deposited Cu-Cr-O thin film consisted of an amorphous phase and exhibited extremely poor optoelectronic properties. After annealing was conducted at 500 degrees C, monoclinic CuO and spinel CuCr2O4 phases were simultaneously formed in the film. Upon increasing the annealing temperature to 600 degrees C, the CuCr2O4 phase reacted completely with the CuO phase and transformed into the delafossite CuCrO2 phase, possessing optimal optoelectronic performance. It has an electrical resistivity of 41 SI-cm and a light transmittance of 49.5%, making it suitable for p-type transparent conducting electrodes. A further increase in annealing temperature resulted in larger grains and greater surface roughness and void density, which, in turn, degraded the optoelectronic performance.
10.2478-msp-2024-0046	-1		This study investigated the impact of adding lead (Pb) and molybdenum disulfide (MoS2) to copper-graphite (Cu-Gr) composites used in electric motors. The composites were produced by mechanical alloying (MA). The mixture was then poured and compressed with varying amounts of Pb and MoS2. Differential thermal analysis was used to determine the sintering temperature of the samples. Further tests were conducted to assess the samples' wear resistance, density, hardness, and porosity. The effects of the additives of these factors were examined, and the output current of the samples was measured. Scanning electron microscopy was also used to analyze the morphology of the Gr plates coated with Cu, Pb, and MoS2. The results indicated that adding Pb and MoS2 increased the density of the sintered samples and their Vickers hardness. Meanwhile, porosity decreased with increased concentrations of Pb and MoS2. Additionally, MoS2 was found to improve wear resistance via a pin-on-disk test.
10.2478-v10172-010-0005-5	4	transformation; martensite; martensitic; phase; shape; beta; memory; shape memory; temperature; temperatures; martensitic transformation; gamma; transformation temperatures; effect; thermal	The phases obtained in copper aluminium bronze alloy (Cu-Al10-Fe2) cast into a permanent die were investigated. The parameters examined were the pre-heating temperatures of the die and the graphite coating thickness. The phases alpha and gamma, were detected as well as the metastable phases beta' and gamma'. The intermetallics of the system Fe-Al were obtained in various stoichiometric compositions. The different cooling rates of the casting resulted in two mechanisms of transformation to alpha grains out of the unstable beta phase, one being nucleation and growth producing needle shaped alpha grains, the other exhibiting a massive transformation to spherical alpha grains. These two mechanisms determine the changes in the size of the alpha grains as a result of changes in the cooling rate in its various ranges.
10.29356-jmcs.v67i4.2042	-1		In the present work, the corrosion behavior of the as-cast Cu-9Al-3Ag alloy, with shape memory, SMA, and with tempering heat treatments at two temperatures, 400 and 600 degrees C, were studied. These treatments were selected due to the austenite-martensite phase transition or vice versa. For this investigation, a 0.5 M NaCl electrolyte was used. Micrographs using optical microscopy and scanning electron microscopy show the martensite phase in the Cu-9Al-3Ag alloy, likewise, in the tempered samples the austenite-martensite phases were also observed. For the evaluation of the corrosion behavior, the Tafel model was implemented, for whose curves a potential of +/- 200 mV was used from the Ecorr. It was observed that the sample with SMA presented a good resistance to corrosion, as well as the tempered samples, unlike the as-cast sample. Finally, impedance tests were carried out using a frequency range of 100 kHz to 10 mHz and an amplitude of 10 mV, in order to observe the resistances to the solution and to the charge transfer present in each one of the samples used.
10.30638-eemj.2011.029	2	corrosion; surface; film; electrochemical; films; spectroscopy; layer; current; solution; potential; resistance; composition; x-ray; ions; showed	Heritage objects made of different metals are exposed to environmental atmospheric impact systematically affected over time by corrosion damage. Corrosion behaviour of Cu-Zn alloy samples (yellow tombac) was studied by accelerated corrosion tests in different environments: continuous wet heating, salt fog and 3.5% NaCl saline. The rate corrosion and resistance of samples was modified according to the corrosive environments tested. Accelerated corrosion tests that were conducted showed a differential behaviour of metal surfaces. By exposing the aggressive corrosion conditions, the samples are shown to be more opaque and have lower values of reflexivity for the ones exposed to salt fog. A morphological analysis was made for metal surfaces by scanning electron microscopy (SEM) and shown the formation of corrosion products due to intensifying the corrosion process, through oxide compounds formed on the sample surfaces, confirmed by XRD diafractograms.
10.3103-S1067821210060088	-1		The influence of annealing (600A degrees C) on the microstructure of L70 cold-rolled brass with additions of bismuth and lead in amounts from 0.001 to 1% is investigated. It is shown that the size of the recrystallized grain is almost independent of these additions, while the Bi-containing and Pb-containing phases themselves are arranged along the grain boundaries and have a spherical shape.
10.3103-S1067821215050107	-1		The peculiarities of the influence of nanodimensional additives of WC, ZrO2, and micrometer particles of hexagonal BN on the compression ratio under cold pressing of briquettes, shrinkage under the solid-phase sintering, and mechanical properties (bending strength limit and hardness) of powder alloys in the Cu-Fe-Co-Ni system are investigated. It is shown that the introduction of alloying additives of WC, ZrO2, and hexagonal BN insignificantly affect the charge resistance to compaction under cold pressing, while they are an additional diffusion barrier in the course of sintering increasing the activation energy. An increase in hardness to 7 HRB and strength to 200 MPa are attained due to the implementation of the effect of dispersed reinforcement in a compact composite.
10.3103-S1067821218050176	-1		The results of the investigation into the formation of amorphous structures in the Cu-Ti system and their subsequent crystallization under the effect of high-energy ball milling (HEBM) are presented. To form amorphous Cu-Ti powders, powders of copper (MPS-V grade with average particle size d = 45-100m, GOST (State Standard) 4960-75) and titanium (PM99.95, d = 2.0-4.5 m, TU (Technical Specifications) 48-19-316-80) are selected as the initial components. The HEBM of Cu + Ti powder mixtures is performed using an Aktivator-2S laboratory planetary ball mill (at revolution rates of discs of 694 rpm and drums of 1388 rpm) for 1-30 min. The investigations into the surface morphology and micro-, nano-, and atomic crystalline structure of activated Cu + Ti powder mixtures are fulfilled by X-ray structural analysis (XSA) using a DRON-3M diffractometer, scanning electron microscopy using a Zeiss Ultra+ microscope (Germany) with the application of energy dispersive analysis, and high-resolution transmission electron microscopy (TEM) using a Titan microscope (United States). The determination of thermal characteristics of phase transformations (temperature, heat of reaction, and amorphous-to-crystalline transition) are performed by differential scanning calorimetry using a DSC 204 F1 device in the mode of linear heating to 450 degrees C at a rate of 20 K/min. The Cu-Ti amorphous powders were fabricated using HEBM for 20 min. The XSA data evidence that the fraction of the amorphous phase in the material was 93%. The TEM investigations showed that the material preferentially consists of the amorphous phase with an insignificant content of nanocrystalline regions 2-8 nm in size. It is found that the Cu-Ti amorphous phase crystallizes in a temperature range of 336-369 degrees C, and the heat of reaction is 79.78 J/g.
10.3103-S1067821219010048	-1		Comprehensive investigations into Cu-ZnO (nano) and Cu-TiN (nano) copper-based materials by standard methods in combination with metallographic and electron microscopy investigations using energy-dispersive and thermal analyses make it possible to identify stable correlation relations between the content of nanoparticle additives, microstructural parameters, and mechanical-and-physical properties of pseudoalloys. Process procedures of increasing the distribution uniformity of modifying additives of ZnO and TiN nanoparticles over the pseudoalloy bulk excluding their conglomeration are developed and substantiated. Novel original methods of nanoparticle introducing into a matrix material in the form of a master alloy made of Cu-Al-ZnO or copper powders coated with TiN nanoparticles are proposed. A high specific surface and reactivity of nanopowders make it possible to lower the ceramic phase in electrocontact materials (down to 2.0-3.0% instead of 10-15% when compared with known commercial brands). This results in the conservation of the main properties characteristic of the matrix material (copper) such as thermal and electrical conductivity at a rather high level, while the general level of physicomechanical characteristics (hardness, strength, and wear resistance) and operational properties of composite pseudoalloys simultaneously increases. The main characteristics of copper-based composite materials are as follows: electrical resistance ( = 0.025 m), bonding strength to the contact support material (sigma similar to 2 MPa), and dispersed ceramic phase inclusions. They reduce the electroerosive wear (up to a factor of 2.5) when compared with conventional materials.
10.3103-S1067821220040069	-1		The influence of titanium and titanium hydride additives on the structure, mechanical properties, and wear resistance of copper alloys intended for use as a binder of the diamond cutting tool is investigated. Powder mixtures Cu-Ti and Cu-TiH(2)are fabricated by mechanical alloying in a planetary centrifugal mill. Such treatment makes it possible to form single-phased powders of the copper-based solid solution in the Cu-Ti system and two-phased powders based on copper with uniformly distributed TiH(2)particles in the Cu-TiH(2)system. It is established that the maximal mechanical properties are characteristic of the samples of compositions Cu-2.5% Ti and Cu-10% TiH2(higher than for pure copper by a factor of 2.0-3.5). Hardening in such alloys is implemented according to the solid-solution mechanism and due to the formation of the Cu3Ti3O phase. Grains of this phase have higher dispersity in alloys where TiH(2)is used as the titanium-containing additive, due to which high values of the bending ultimate strength (920 MPa) and hardness (114 HB) are attained. It is established according to the results of comparative tribological investigations that samples of the Cu-10% TiH(2)composition possess the best wear resistance. The reduced wear of these samples after the test according to the rod-disc scheme is an order of magnitude lower than for pure copper and lower by a factor of 5 than for Cu-2.5% Ti samples.
10.3103-S1068366611020139	-1		It is demonstrated that the wear rate of tribocouples can be reduced significantly with the use of lubricating compositions obtained by added super- and nanodispersed zinc or Cu-Sn powders to the Lithol-24 plastic grease. When the superdispersed powders of copper alloys interact with tribosurfaces, the copper and tin diffuse into the base metal, producing secondary composite superdispersed structures. The alloyed elements penetrate into the base metal more deeply if the powder contains the nanodispersed fraction. The films of polyfluorinated oligomers based on particles of zinc and copper alloy powders with functional substitutes reduce substantially the friction coefficient of kinematic couples when they are lubricated with these lubricating compositions and expand the temperature range of application of plastic greases.
10.3103-S1068366623040025	-1		The features of the structural and tribotechnical characteristics of copper alloys and coatings during friction of a steel-steel pair are analyzed. Copper-based coatings obtained by gas-dynamic spraying have been experimentally studied. The wear resistance and microgeometric characteristics of the surface of steels with coatings of the composition Cu : Al2O3 = 55 : 45 (wt%) and Cu : Zn : Al2O3 = 35 : 35 : 30 (wt%) are determined. A coating is formed from a powder mixture of copper and corundum, mainly consisting of copper. Corundum is present in the form of particles with a size of 0.05 mu m(2) in an amount of less than 1%. The coating has a high performance when tested under friction and wear conditions: wear intensity I-h (coating) approximate to (1.1-1.5) x 10(-10) and I-h (counterbody) approximate to (0.3-0.4) x 10(-11) under friction in I-20A mineral oil; I-h (coatings) approximate to (2-5) x 10(-10) and Ih (counterbodies) approximate to 0.2 x 10(-11) during friction in Litol-24 grease. Heat treatment of such a coating causes diffusion of zinc into copper with the formation of a solid solution of zinc in copper (alpha-phase) and an electron-type solid solution based on CuZn is also formed. The mechanism of contact interaction of steel coated with Cu-Zn-Al2O3 in a pair with ShKh15 steel is based on the process of mass transfer in the zone of surface plastic deformation, which minimizes the level of surface destruction of the pair as a whole, reducing it to practical wearlessness at high external pressures. Deformation, diffusion, and mass transfer in the zone of contact interaction during friction point to the effect of classical wearlessness, a distinctive feature of which is the formation of a copper-zinc third body interspersed with corundum, which has the ability to transfer from the sample on the counterbody and vice versa, providing protection of the surface layers from destruction but not a servovite copper film (with a special structural state). High wear resistance of friction pair materials is achieved due to frictional mass transfer films.
10.3139-124.110290	-1		Cu-Al bimetallic nanoparticles were synthesized by gamma irradiation technique in aqueous solutions containing metal chlorides as precursors, polyvinyl alcohol (PVA) as a capping agent, isopropanol as a radical scavenger, and distilled water as a solvent. The Cu-Al bimetallic nanoparticles were characterized by transmission electron microscopy (TEM), UV-visible absorption spectrometry, powder X-ray diffractometer (XRD), and Energy-dispersive X-ray spectroscopy (EDX). The TEM, XRD, EDX, and absorption analyses confirmed the formation of core-shell structure of Cu-Al bimetallic nanoparticles at lower Cu2+/Al3+ mole ratio, and the formation of Cu-Al alloy nanoparticles at higher Cu2+/Al3+ mole ratio. The TEM analysis for particle size and size distribution revealed that the average particle size of Cu-Al bimetallic nanoparticles decreased with the increase of absorbed dose. It may be explained due to the competition between nucleation and aggregation processes in the formation of metallic nanoparticles under irradiation.
10.3139-146.031199	-1		High-energy synchrotron radiation has been used to study in situ annealing of cold-rolled Cu and Ti. The measurements were performed using a high-vacuum furnace in transmission geometry and an area detector. The diffraction images were subsequently processed to extract the orientation distribution. The recrystallization process could be followed with a time resolution of the order of 10 s, and good pole figures could be obtained from the very limited amount of data in single diffraction images. The pole figures compare favorably with pole figures of the same material measured ex situ with a conventional pole figure goniometer. For Cu, a rapid and complete change from a typical rolling texture to a cube texture was observed after annealing for 20 min at 650degreesC. For Ti, changes were more subtle with a tendency for c-axes to diminish near the normal direction, as well as for a-axes to become aligned with the rolling direction. The method makes it feasible to study the kinetics of recrystallization with quantitative texture analysis.
10.3139-146.110287	-1		The relationship between the microstructures and the properties of nano-scale Fe-Co magnetic particles formed in a copper alloy was investigated. Several structural aspects and physical properties of Fe-Co precipitates were investigated simultaneously using transmission electron microscopy, high resolution transmission electron microscopy, and superconducting quantum interference device magnetometry. The microstructure and magnetic properties of precipitates comprising both Fe and Co atoms evolved with isothermal annealing at 873 K. We found that the evolution of small coherent precipitates obeys the Ostwald ripening law; however, the coarsening rate of the particles increased after coherent particles transformed into incoherent precipitates. The coercive force varied, correlating with the evolution of precipitates.
10.3139-146.110595	4	transformation; martensite; martensitic; phase; shape; beta; memory; shape memory; temperature; temperatures; martensitic transformation; gamma; transformation temperatures; effect; thermal	Different fragments of martensitic Cu-14.86 Zn-5.81 Al-0.5 Fe (mass.%) shape memory alloy were subjected to heating, up to 453 K, with different rates ranging from 1.66 x 10(-2) K s(-1) to 54.6 x 1.66 x 10(-2) K s(-1), performed by means of a differential scanning calorimeter. In all cases, during heating, an endothermic peak was observed which was associated with the martensite reversion to parent phase. By means of the differential scanning calorimeter charts the critical transformation temperatures of martensite reversion were determined using the tangent method. The effects of heating rate were evaluated from the point of view: (i) of variation tendencies of critical transformation temperatures; (ii) of deviations of experimental values from linear fit and extrapolation to zero heating rate; and (iii) of corroborating morphological changes of martensite (sub)plates with heat flow variation particularities. The results prove that there is an obvious tendency of critical transformation temperatures, of reverse martensitic transformation, to linearly increase with heating rate. The effectiveness of the linear relationships was checked for two heating rate values located inside and outside the above mentioned range, respectively and the difference between the experimental and calculated values of critical transformation temperatures fell within the range (-3 ... +4) parts per thousand.
10.3139-146.110876	12	thermodynamic; ternary; phase; data; experimental; equilibria; phase equilibria; liquid; binary; experimental data; calculated; phases; literature; model; calphad	In this study isothermal equilibration experiments were done at 866-1166 K for the copper lead (Cu-Pb) binary system. The experiments, conducted in a quartz ampoule, enabled the solubility limits at each end of the phase diagram to be obtained. In addition to the experiments, a literature survey and compilation of the experimental data of the solid solubilities was done. Critically evaluated and selected literature data and our own experimental values were used to optimise the fcc phase interaction parameters. According to the experiments the lead solubility in solid copper at the copper-rich end is smaller than previously reported. The liquidus curve at the lead-rich end was validated with our own experimental results, which agree well with previous experimental data. The thermodynamic assessment of the Cu-Pb system, in the area of fcc_Al solid solutions, has been improved.
10.3139-146.111006	2	corrosion; surface; film; electrochemical; films; spectroscopy; layer; current; solution; potential; resistance; composition; x-ray; ions; showed	This study investigates the corrosion behavior of Cu-35Zn brass with 0 and 5 wt% of tin in NaCl solution with a mass concentration of 3.5% containing 0, 400 and 1200 ppm of sulfide ions. For the purpose of assessing the corrosion behavior, open circuit potential, linear polarization resistance, electrochemical impedance spectroscopy and potentiodynamic polarization studies were employed. The results of the study show that on increasing the S2- concentration, an increase in the corrosion rate of the samples was observed. Moreover, the addition of Sn to the alloy leads to an increase in the polarization resistance and electrochemical impedance of the alloy. The corrosion potential as well as the corrosion current density were calculated using the Tafel extrapolation method. Addition of S2- shifts E-corr towards more negative values and increases i(corr). The surface of the samples was studied using light optical microscopy and pits were mainly observed in the grain boundaries of the Cu-35Zn sample.
10.3139-146.111475	17	wear; composites; coating; friction; composite; coatings; surface; tribological; properties; wear resistance; resistance; powder; sliding; matrix; wear rate	Composite powders of Ni-30SiC (vol.%) were fabricated by mechanical alloying. Scanning electron microscopy, transmission electron microscopy and energy dispersive X-ray spectroscopy were used to analyze the microstructure, morphology and composition of the composite powders. Mixed powders and Ni coating layers on the surface of SiC particles were investigated. The Ni/SiC composite powder with the optimal coating was mixed with Cu powder to manufacture Cu matrix composites by powder metallurgy, and the relative density, hardness and electrical resistivity of the composites were measured. The results show that the Ni coating becomes increasingly prominent and that the mixed powders become increasingly homogeneous as the ball-milling time increases; however, an excessively long milling time has a negative impact on the coating. The milling speed also has an important effect on the coating. Too high of a rotational speed quickens the rate of work hardening of the coating layer, which causes the coating layer to fall off. When the milling time is 20 h, the milling speed is 300 r min(-1) and the ball to powder weight ratio is 10 : 1, the SiC particles are well coated by Ni and the powders are uniformly mixed. The properties of the copper matrix composite processed with the optimal milling parameters are effectively improved.
10.31577-km.2023.6.351	4	transformation; martensite; martensitic; phase; shape; beta; memory; shape memory; temperature; temperatures; martensitic transformation; gamma; transformation temperatures; effect; thermal	In this work, the new quaternary CuAlTiMg high-temperature shape memory alloy (HTSMA) with an unprecedented composition and with extended solubility of Ti was produced by the arc melting method. The thermal shape memory effect characterization tests were done by performing a series of differential calorimetric (DSC and DTA) measurements. The obtained thermograms of the alloy displayed the martensitic phase transformation peaks. The forward (martensite to austenite) phase transformation was found to occur at above 350 degrees C, which qualifies the produced alloy as an HTSMA. The microstructural XRD measurement was performed to reveal the atomic planes of martensite structures formed in the alloy, which constitute the shape memory effect property of the fabricated alloy. The alloy surface was monitored by optical microscopy image taken at room temperature, and finely dispersed Ti-rich X-phases were observed.
10.31577-km.2024.5.275	-1		In this study, samples were produced by powder metallurgy, adding 0.25 wt% h-BN and 0.25, 0.5, 1, 2, 4, and 5 wt% SiC to Cu, Zn, and Sn metallic powder mixtures. The samples were mixed using high-energy mechanical alloying and compacted under a 400 N mm-2 pressure. Subsequently, they were sintered for 2 h at 820 degrees C in a controlled atmosphere furnace. Characterization processes included hardness measurement, XRD analysis, dimensional changes, and electron and optical microscopy. The results of the study revealed that the dimensional change after sintering increased initially with the addition of SiC and then decreased as the addition amount increased. XRD analysis identified characteristic peaks of the reinforcement materials and the metallic matrix. SEM analysis confirmed the distribution of h-BN and SiC within the metallic matrix. Wear resistance was significantly improved with increasing SiC addition in the 3 N load wear tests, remaining unchanged in the 1 N load wear tests. Furthermore, an increase in SiC content led to consistent friction coefficients at each stage of the wear test, while SiC-free samples exhibited load-dependent changes in friction coefficients.
10.3176-proc.2019.1.02	-1		In this study, Cu-25WC, Ni-25WC, and Fe-25WC (all in wt%) composite powders were produced via mechanical alloying (MA) and characterized for their potential utilization in particulate materials based technologies. The changes in the crystallite size (D) and lattice strain (epsilon) during the production of WC particle reinforced Cu, Fe, and Ni composite powders via MA were investigated. The Williamson-Hall (W-H) plot analysis and fundamental parameters approach (FPA) applied with Lorentzian function were used to evaluate epsilon and D of matrix phases from XRD results. With increasing MA, epsilon values of all matrix phases showed an increase whereas D values showed a decrease. In addition to that, lattice parameters a(Cu) and a(Ni) changed linearly with time, and a(Fe) displayed a slight decrease. The XRD peak belonging to the Cu (111) plane shifted towards larger 2-theta angles in the same direction. Contrary to Cu, the Fe (110) peak shifted to lower angles with MA time. However, the XRD peak belonging to the Ni (111) plane changed alternately. Similar results were obtained from both W-H plot analysis and the FPA calculations Minimum crystallite size and maximum internal strain rates were estimated for 8 h MA'ed Cu25WC, Fe25WC, and Ni25WC composite powders as 14.63 nm and 1.39%, 7.60 nm and 1.23%, and 17.65 nm and 1.13%, respectively. Transmission electron microscope observations were found in good agreement with the crystallite size of XRD calculations.
10.32604-cmc.2025.059727	14	strength; properties; conductivity; electrical; mechanical; cu-; grain; mpa; electrical conductivity; aging; precipitation; phase; mechanical properties; tensile; phases	To explore atomic-level phenomena in the Cu-Ni-Sn alloy, a second nearest-neighbor modified embedded-atom method (2NN MEAM) potential has been developed for the Cu-Ni-Sn system, building upon the work of other researchers. This potential demonstrates remarkable accuracy in predicting the lattice constant, with a relative error of less than 0.5% when compared to density functional theory (DFT) results, and it achieves a 10% relative error in the enthalpy of formation compared to experimental data, marking substantial advancements over prior models. The bulk modulus is predicted with a relative error of 8% compared to DFT. Notably, the potential effectively simulates the processes of melting and solidification of Cu-15Ni-8Sn, with a simulated melting point that closely aligns with the experimental value, within a 7.5% margin. This serves as a foundation for establishing a 2NN MEAM potential for a flawless Cu-Ni-Sn system and its microalloying systems.
10.3365-KJMM.2021.59.7.505	-1		A three-dimensionally interconnected hexagonal boron nitride (3Di-hBN) networked Cu-Ni (3Di-hBN-Cu-Ni) composite was successfully synthesized in situ using a simple two-step process which involved the compaction of mixed Cu-Ni powders (70 wt% Cu and 30 wt% Ni) into a disc followed by metal-organic chemical vapor deposition (MOCVD) at 1000 degrees C. During MOCVD, the Cu-Ni alloy grains acted as a template for the growth of hexagonal boron nitride (hBN) while decaborane and ammonia were used as precursors for boron and nitrogen, respectively. Boron and nitrogen atoms diffused into the Cu-Ni solution during the MOCVD process and precipitated out along the Cu-Ni interfaces upon cooling, resulting in the formation of the 3Di hBN-Cu-Ni composite. Energy-dispersive spectroscopic analysis confirmed the presence of boron and nitrogen atoms at the interfaces of Cu-Ni alloy grains. Optical microscopy examination indicated that there was a minimum amount of bulk hBN at a certain compaction pressure (280 MPa) and sintering time (30 min). Scanning electron microscopy and transmission electron microscopy revealed that an interconnected network of hBN layers surrounding the Cu-Ni grains developed in the 3Di-hBN-Cu-Ni composite. This 3Di-hBN network is expected to enhance the mechanical, thermal, and chemical properties of the 3Di-hBN-Cu-Ni composite. Moreover, the foam-like 3Di-hBN extracted from 3Di-hBN-Cu-Ni composite could have further applications in the fields of biomedicine and energy storage.
10.3389-fchem.2020.00272	2	corrosion; surface; film; electrochemical; films; spectroscopy; layer; current; solution; potential; resistance; composition; x-ray; ions; showed	The present work focuses on the characterization of brass surfaces after contact with artificial saliva solution at pH 7.4 and phosphate buffer solution at pH 7 simulating two extreme conditions that might occur when playing ancient brass wind instruments in the context of historically informed performance practice. The composition and the morphology of the film formed following the contact with the solutions for 1, 3, and 16 h were investigated by ex situ X-ray photoelectron spectroscopy (XPS) and scanning electron microscopy (SEM) to shed a light on the surface changes upon time. In situ electrochemical impedance spectroscopy (EIS) was used to study the mechanism of corrosion and protection of the alloys. The results could be interpreted using a reliable equivalent electrical circuit; they provided evidence that the alloys behave differently when in contact to the various solutions. In saliva solution the formation on the brass surface of a thick surface film was observed, composed of crystallites of about 200 nm size mainly composed of CuSCN and Zn-3(PO4)(2). This layer hinders the alloy dissolution. The contact of the alloys with the buffer solution originated a much thinner layer composed of Cu2O, ZnO, and a small amount of Zn-3(PO4)(2). This film is rapidly formed and does not evolve upon time in a protective film.
10.3389-fmats.2020.577867	8	hot; deformation; strain; strain rate; dynamic; hot deformation; recrystallization; dynamic recrystallization; flow; rate; flow stress; compression; constitutive; degrees; stress	Three constitutive models, strain-compensated Arrhenius model, modified Johnson-Cook (JC) model, and modified Zerilli-Armstrong (ZA) model, were established for the hot-deformed Cu-15Ni-8Sn alloy based on hot compression tests. By introducing average absolute relative error (AARE), correlation coefficient (R), and relative error, the prediction accuracy of these three models was assessed. The results indicate that strain-compensated Arrhenius model has the highest accuracy at describing the flow stress behavior of the studied alloy, followed by modified JC model and modified ZA model. Moreover, the strain-compensated Arrhenius model established in this work has a great practicability in the hot-extrusion simulation of Cu-15Ni-8Sn alloys. This article provides a theoretical basis for optimizing hot deformation parameters in industrial production of the Cu-15Ni-8Sn alloys.
10.3389-fmats.2022.886788	7	irradiation; shear; grain; ta; deformation; size; radiation; voids; nanocrystalline; simulations; similar; void; temperature; irradiated; boundaries	We identified two glass phases formed in three undercooled liquids of elemental Ag, binary Cu-Ag, and binary Cu-Zr alloys using molecular dynamics (MD) simulations: 1) The homogeneous L-phase arises from quenching quickly from high temperature liquid. 2) The heterogeneous solid-like G-phase arises from the isothermal equilibration at temperatures below the melting point. The G-phase exhibits a core-shell structure with the ordered cores surrounded by percolating liquid-like shells. The distinguishable structures between these two phases are expected to different mechanical behavior. The present study reports MD simulations to compare the shear deformation of these two phases in binary Cu2Zr system. At room temperature, the G-phase exhibits a higher critical stress, a higher critical strain, and higher shear modulus than the L-phase, suggesting that the G-phase has improved strength and rigidity compared to the homogeneous L-phase. The plastic yielding mechanism of both the G-phase and L-phase is accompanied by shear band formation. However, the formation of shear band in G-phase is confined by the cores to a highly localized region and characterized by local mechanical melting. In contrast, the shear band in L-phase exhibits greater width and much more homogenous character. We conclude that the mechanical properties of a metallic glass will vary significantly according to the type of glassy phase formed during processing.
10.3389-fmicb.2023.1149110	2	corrosion; surface; film; electrochemical; films; spectroscopy; layer; current; solution; potential; resistance; composition; x-ray; ions; showed	Despite its excellent corrosion resistance, B30 copper-nickel alloy is prone to pitting, particularly when exposed to microorganisms. The mechanism underlying the acceleration of pitting in this alloy is not fully understood. In this study, the acceleration of pitting corrosion in B30 copper-nickel alloy caused by a marine microorganism named Pseudomonas aeruginosa (P. aeruginosa) was investigated using surface analysis and electrochemical techniques. P. aeruginosa significantly accelerated the pitting in B30 copper-nickel alloy, with a maximum pitting depth of 1.9 times that of the abiotic control and a significant increase in pitting density. This can be attributed to extracellular electron transfer and copper-ammonia complex production by P. aeruginosa, accelerating the breakdown of the passivation film.
10.3390-app11167762	-1		Copper-Beryllium alloys have excellent wear resistance and high mechanical properties, they also possess good electrical and thermal conductivity, making these alloys very popular in a wide variety of industries, such as aerospace, in the fabrication of tools for hazardous environments and to produce injection molds and mold inserts. However, there are some problems in the processing of these alloys, particularly when these are subject to machining processes, causing tools to deteriorate quite rapidly, due to material adhesion to the tool's surface, caused by the material's ductile nature. An assessment of tool-wear after machining Cu-Be alloy AMPCOLOY 83 using coated and uncoated tools was performed, offering a comparison of the machining performance and wear behavior of solid-carbide uncoated and DLC/CrN multilayered coated end-mills with the same geometry. Multiple machining tests were conducted, varying the values for feed and cutting length . In the initial tests, cutting force values were registered. The material's surface roughness was also evaluated and the cutting tools' edges were subsequently analyzed, identifying the main wear mechanisms and how these developed during machining. The coated tools exhibited a better performance for shorter cutting lengths, producing a lower degree of roughness on the surface on the machined material. The wear registered for these tools was less intense than that of uncoated tools, which suffered more adhesive and abrasive damage. However, it was observed that, for greater cutting lengths, the uncoated tool performed better in terms of surface roughness and sustained wear.
10.3390-app112210843	17	wear; composites; coating; friction; composite; coatings; surface; tribological; properties; wear resistance; resistance; powder; sliding; matrix; wear rate	To improve the processing efficiency and the surface properties of C61900 Cu alloy, a gradient Cu-Ti film with a Ti/Cu atom ratio of 7:1, 7:4, and 1:2 was pre-fabricated by the unbalanced magnetron sputtering process and then nitrided by thermos plasma nitriding. The phase structure, elemental composition, and morphology of the modified surface were characterized, and the mechanical properties, including the wear resistance and adhesion properties, were examined. Combining calculation by the first principle method with thermodynamic analysis, the microstructural formation and phase composition of the Cu-Ti-N system were investigated to reveal the mechanism of improved wear resistance, which indicated the possible formation of various Cu-Ti intermetallics and Ti-N compounds. The Al in the C61900 Cu substrate also participated in the generation of the AlCu2Ti compound, which is a ductile phase with good hardness and elastic modulus. Based on the results of a mechanical properties test, it was concluded that an optimized layer structure for the multi-phase coating should include Ti-N compounds as the surface layer and Cu-Ti intermetallics as the intermediate layer.
10.3390-app112211023	-1		In the process of copper alloy hot continuous rolling, the problem of copper sticking to the roller seriously affects the surface quality, performance, and service life of the copper products. Roll sticking occurs as the adhesion energy of Cu is lower than that of Fe and the Fe-Cu interface, and the severe surface deformation which forces the copper into direct contact with the roll during the process of profile rolling. Based on the copper deformation law and adhesion phenomenon in the hot continuous rolling process, a rolling deformation model and roll copper adhesion model or copper alloy hot continuous rolling were established, and their simulation was realized using finite element software. Through finite element modeling of the hot rolling deformation zone, the distribution of the temperature, contact normal stress, and exposure rate in the hot rolling deformation zone were obtained, which were consistent with the actual roll adhesion phenomenon and copper adhesion position. To address the copper sticking behavior of the rolls, the process optimization method of matching the motor speed with the elongation coefficient (the 1# and 2# motor speeds were adjusted to 1549 r/min and 1586 r/min, respectively), adjusting the roll gap to 7.9 mm, and increasing the number and pressure of roll spray nozzles were put forward, which effectively solved the problem of copper sticking to the roll, significantly improved the surface quality of the copper and the service life of the roll, and can be used in production.
10.3390-app12030946	-1		In this study, molecular dynamics simulations have been used to study the influencing factors, such as the time of each heating step, temperature, and annealing time, on the structure and crystallization process of Cu-Au alloy. The results show that when the temperature increased, the crystallization process decreased, and the structure gradually turns to the liquid state, and vice versa. When increasing the time of each heating step and the annealing time, the crystallization process increased, then increased the most at the glass temperature, T-g = 550 K. During the phase transition, link length (r), total energy (E-tot), size (l), number of FCC, HCP, and Amor structural units have a significant change. The obtained results of Cu-Au alloy can serve as a basis for future experimental studies.
10.3390-app13031754	16	wear; composite; composites; powders; milling; particles; powder; wt; sliding; friction; hardness; matrix; mechanical; surface; properties	This study focuses on a comparative analysis of mechanical behavior and microstructural characteristics of Cu matrix (C87600) based hybrid composites reinforced with SiC-Gr(p) and WC-Gr(p) fabricated by the stir casting process. The graphite particle percentage was kept constant, whereas the content of SiC and WC in the respective composites was varied to analyze the mechanical properties of the fabricated composites. The morphological observation was carried out by field emission scanning electron microscope (FESEM), which revealed uniform dispersion of the reinforced particles in the hybrid composites. Clear phases of SiC and WC along with the Cu alloy were identified by the x-ray diffractometer (XRD). Further, a comparative study was conducted to analyze the mechanical behavior of the Cu-SiC-Gr and Cu-WC-Gr hybrid composites. With the addition of the hard ceramic materials, the tensile behavior and microhardness of both the Cu-based MMCs were improved. The WC-Gr reinforced composites exhibited higher mechanical properties than the SiC-Gr reinforced hybrid composites. Further, the fracture surfaces were also characterized to study the tensile behavior of the fabricated copper-based hybrid composites, which shows that ductile fracture was mainly associated with both hybrid composites.
10.3390-app13148540	-1		Among the amazing properties of graphene, superlubricity is one of the most promising properties. This property can be used in industrial field components to reduce friction without using liquid lubricants, and therefore, improve machines' efficiency and reliability with low environmental impact thanks to the elimination of oil or grease lubricants. In this paper, copper alloy samples for electrical purposes were coated with graphene by four different deposition processes. The investigated synthesis processes are direct grown graphene on bulk Cu, transferred graphene, and self-assembled graphene from graphene flakes. Ball-on-disk tests were performed to evaluate the tribological performance of samples. The aim was to compare the effect on the tribological performance given by different types of coatings, taking also into consideration industrial scalability. Interestingly, not all graphene nano-coatings being compared proved effective in reducing friction and wear in gross sliding conditions. The results show that the cost-effective self-assembled graphene is the longer-lasting nano-coating among those investigated in this work, and can reduce both friction and wear. Tests revealed that graphene coatings can be applied as a solid lubricant, reducing friction up to 78%, and reducing the average wear volume up to 40%.
10.3390-app142210406	14	strength; properties; conductivity; electrical; mechanical; cu-; grain; mpa; electrical conductivity; aging; precipitation; phase; mechanical properties; tensile; phases	This paper investigates the interrelated effects of thermomechanical treatments and chemical composition on the phase transformation capabilities of thin sheets made from Cu-Al-Mn shape memory alloys. The transformation capacity and transition temperatures were determined using DSC and DMA testing, while composition measurements were performed using SEM/EDX analysis. The results demonstrate that applying hot-rolling treatments to alloys of reduced thickness leads to manganese oxidation and modifications in chemical composition, adversely impacting the phase transformation performance. This effect can be mitigated by the use of cold rolling. Additionally, the presence of phosphorus impurities can create inclusions that bind manganese, preventing it from remaining in the solid solution and further affecting phase transformation capabilities.
10.3390-app9183896	2	corrosion; surface; film; electrochemical; films; spectroscopy; layer; current; solution; potential; resistance; composition; x-ray; ions; showed	In this work, the corrosion mechanism of a Cu-5Zn-5Al-1Sn alloy was examined in a 3.5 wt% NaCl solution. At the same time, the effect of a cysteine inhibitor was also investigated through a multi-analytical approach . Electrochemical results suggested that inhibition efficiency increased with the increase of cysteine concentration. From potentiodynamic polarization (PD) analysis, a decrease in corrosion current and corrosion potential shift toward a more negative direction was observed. The potential difference between the blank and inhibited surface was found to be 46 mV, which is less than 85 mV, revealing a mixed type inhibition effect of cysteine for the Cu-5Zn-5Al-1Sn alloy. The inhibition mechanism of cysteine (Cys) and the effect of alloying elements were investigated by fitting experimental impedance data according to a projected equivalent circuit for the alloy/electrolyte interface. A Langmuir adsorption isotherm was proposed to explain the inhibition phenomenon of cysteine on the Cu-5Zn-5Al-1Sn alloy surface. Surface morphology observation confirmed that the Cu-5Zn-5Al-1Sn alloy was damaged in 3.5 wt% NaCl solution and could be inhibited by using the cysteine inhibitor. The impact of alloying elements on the corrosion mechanism was further examined by surface analysis techniques such as X-Ray photoelectron spectroscopy (XPS)/Auger spectra, the results of which indicated that the corrosion inhibition was realized by the adsorption of the inhibitor molecules at the alloy/solution interface.
10.3390-buildings11010022	4	transformation; martensite; martensitic; phase; shape; beta; memory; shape memory; temperature; temperatures; martensitic transformation; gamma; transformation temperatures; effect; thermal	In order to develop the application of the more cost-effective copper-based shape memory alloys (SMAs), rather than nickel-titanium as earthquake energy dissipaters, the influence of ausforming-induced plastic deformation on phase transformations, microstructure, super elasticity and mechanical properties of the shape memory alloy Cu-26Zn-4Al was examined. These specific SMA properties were targeted by applying appropriate parameters of the thermomechanical (the so-called ausforming) process: beta-phase homogenization at 800 degrees C for 20 min, one-step hot rolling at 800 degrees C and water quenching. The results showed significant microstructural changes, increased mechanical resistance and change in the phase transformation behavior. The SMA treated by ausforming retained the reversible austenitic-martensitic transformation ability, with the appearance of the super-elastic effect up to 6% of strain recovery. Although some strengthening occurred after hot rolling (an increase in true yield strength of 125 MPa was detected), all phase transformation temperatures were decreased. The smallest decrease was detected for the austenite finish temperature (32.8 degrees C) and the largest for the martensite finish temperature (42.0 degrees C), allowing both the expansion and the lowering of the temperature range of super elasticity, which is favorable for construction applications. It is concluded that it is possible to achieve an optimal combination of adequate strength and improved transformation behavior of Cu-Zn-Al alloy by applying the ausforming treatment.
10.3390-coatings10060515	2	corrosion; surface; film; electrochemical; films; spectroscopy; layer; current; solution; potential; resistance; composition; x-ray; ions; showed	Cu-Zr-Ta ternary thin film metallic glasses (TFMGs) were deposited through the direct current (DC) magnetron sputtering of pure metallic targets in a dynamic mode. The effect of tantalum addition on the microstructure, mechanical properties, and thermal behavior of TFMGs were investigated. Nanoindentation measurements showed that an increase in tantalum content from 0 to 47 at% favored hardness and Young's modulus, which rose from 5.8 to 11.23 Gpa and from 90 to 136 Gpa, respectively. XRD analysis and differential scanning calorimetry (DSC) measurements highlighted an improvement of thermal stability with the tantalum addition from 377 to 582 degrees C when the tantalum content increased from 0 to 31 at%.
10.3390-coatings10100926	-1		In this study, a multilayered hard coating with a tungsten matrix and a transition layer was deposited on pure copper by double glow plasma surface alloying technology, which aimed to provide the coating superior binding force and favorable matching of mechanical properties. The micro-hardness tester was adopted to measure the surface and cross-sectional hardness of the coatings. The nanoindentation test was used to measure the elasticity modulus of the coatings. Sliding wear tests under different conditions were performed on the W/Ta multilayer coating as well as the Cu substrate and W coating. The fairly low specific wear rate of the multilayer coating proved its excellent wear-resisting property, and the wear mechanism of the multilayer coating was mainly abrasive wear. In addition, a scratch test was executed to evaluate the deformation mechanism of the coating. Compared to the W coating, the persistence of the changing elastic-plastic deformation in the W/Ta multilayer coating improved the adhesion and resistance to plastic deformation. Moreover, the changing elastic-plastic deformation region is a benefit to the wear process, and the mechanical properties of the transition layer present a linear gradient descent instead of a vertical gradient, which makes a significant contribution in the wear stage. Further, the exploration of deformation mechanisms has a significant contribution to the design for multilayered hard coatings.
10.3390-coatings11121563	2	corrosion; surface; film; electrochemical; films; spectroscopy; layer; current; solution; potential; resistance; composition; x-ray; ions; showed	Electrodeposition of Cu-Ag films from acidic sulfate bath was conducted at n-Si(001) and polycrystalline Ru substrates. Significant nucleation overpotential of 0.4 V is observed with the Cu-Ag bath at n-Si(001) substrate, whereas the electrodeposition of Cu-Ag at Ru substrate is influenced by Ru oxides at the surface. Incomplete coverage of Si substrate by Cu-Ag deposit was observed from the deposition systems without Ag(I), or with 0.1 mM Ag(I), comparing with the compact Cu-Ag film obtained with the deposition bath containing 0.01 mM Ag(I). Layered and faceted Cu-Ag deposit was observed at small Cu deposition overpotential with the Ru substrate. Phase composition of the Cu-Ag deposits at n-Si(001) substrate from electrolyte with various Ag(I) concentrations is examined by XRD. Limited solubility of Ag (0.4 at%) was observed in fcc-Cu until phase separation occurs. The classical model for nucleation kinetics in electrodeposition was used to examine the potentiostatic transients of the Cu-Ag electrodeposition at n-Si(001) substrate.
10.3390-coatings12050682	17	wear; composites; coating; friction; composite; coatings; surface; tribological; properties; wear resistance; resistance; powder; sliding; matrix; wear rate	High Cu-Pb-Sn, as the material for bimetallic cylinder block, is widely used in the selection of wear-resistant parts due to its excellent wear reduction, thermal conductivity, fatigue resistance, and strong bearing capacity, such as bearings and bearing bushes, aerospace pump rotor, turbine and guide plate, etc. However, because its wear resistance is not enough to meet the harsh conditions of high temperature, high speed, and heavy load, the research on high wear resistance Cu-Pb-Sn materials has important theoretical significance and application value for the application of bimetallic materials. ZCuPb(20)Sn(5) alloy was taken as the research object to analyze the influence mechanism of its different microstructure and mechanical properties on the friction and wear properties of alloy materials. Friction experiments under two conditions of oil lubrication and dry friction were carried out on the MMW-1A pin-on-disc friction and wear testing machine. The wear resistance and wear mechanism of ZCuPb(20)Sn(5)alloy under the action of Cu3P were discussed, and a high wear-resistant Cu-Pb-Sn alloy for bimetal cylinder block was prepared. The results show that with the increase of P content, both the friction coefficient and wear rate decrease, and the wear reduction of ZCuPb(20)Sn(5) alloy increases. Under oil lubrication conditions, the friction coefficient decreases by 21.4% and the wear rate decreases by 85.5% compared with that without adding P. The friction-reducing and wear-resistant properties of ZCuPb(20)Sn(5) alloy materials are increased. In dry friction and oil lubrication, the mass wear amount of ZCuPb(20)Sn(5) alloy material decreases with the increase of P element addition, and the change rule of alloy wear amount is consistent under the two methods. In the process of friction and wear, adhesive wear occurs, and the wear amount of the alloy material increases. With the increase of P content, the lead particles are refined and evenly distributed, which promotes the formation of a uniform self-lubricating lead film during the friction process and reduces the degree of adhesive wear. The appearance of Cu3P reduces the contact area of the friction surface and weakens the adhesive wear, so the wear rate is reduced.
10.3390-coatings12091236	-1		The impact property is one of the most significant mechanical properties for metallic materials. In the current work, a soft-hard copper-brass block with a high yield strength of similar to 320 MPa and good uniform elongation of similar to 20% was prepared, and the effect of the testing temperature on its impact property was explored. The results showed that the impact energy was decreased with the increase in testing temperature. The impact energies at liquid nitrogen temperature (LNT), room temperature (RT), and 200 degrees C were 8.15 J, 7.39 J, and 7.04 J, respectively. The highest impact energy at LNT was attributed to the coordinated plastic deformation effects, which was indicated by the tiny dimples during the process of the delamination of soft-hard copper-brass interfaces. The high temperature of 200 degrees C can weaken the copper-brass interface and reduce the absorption of deformation energy, result in low impact energy.
10.3390-coatings12091360	-1		Due to the huge difference in thermophysical properties, it is difficult to obtain a defect-free bonding interface between copper and steel. A Cu-Ni-Ti interlayer was added between a TiC-reinforced copper matrix composite coating and Q235 steel in this study to improve its interfacial bond. The influence of the interlayer on its microstructure and properties was studied by characterizing microstructure, phase composition, and wear resistance of the composite coatings. Both coatings were found to consist of alpha-Cu matrix, in situ-generated TiC, and Fe-rich phases. With the addition of the Cu-Ni-Ti interlayer, the high-hardness unmixed zone at the interface was successfully eliminated due to the sufficient mixing of the molten pool. Even more importantly, liquid metal embrittlement cracks were also restrained, resulting from the Fe-rich solid solution band that reduced the contact probability around liquid copper atoms with the steel grain boundaries formed. In addition, the results showed that the microhardness of composite coatings was improved and the wear loss reduced by 4.2% after adding that interlayer, which was related to the combined action of solid solution strengthening, second-phase strengthening and grain-refinement strengthening mechanisms.
10.3390-coatings12101484	-1		High-power impulse magnetron-sputtering thick metal/carbon-nitride-doped metal-matrix multilayer nano-composite coating can be applied to cutting-tool holder components to improve cutting insert's life. One of the challenges of such an add-on solution is the poor adhesion between the thick coating and the hard alloy substrate, such as WC-Co shim. This work presents a study on WC-Co substrate surface preparation methods for HiPIMS coating and its adhesion improvement. Three mechanical surface pretreatment methods were investigated: machining (grinding), diamond polishing, and grit blasting. White-light interferometry was used for substrate surface texture measurement before and after pretreatment. It was demonstrated that, compared to machining and diamond polishing, grit blasting can significantly improve the interface adhesion between the similar to 200 mu m-thick Cu:CuCNx coating and WC-Co shim. Grit blasting was also found to be beneficial for improving the cutting insert's life in the external turning process. In turning tests, the coating lifetime for grit-blasted shim was more than 90 min, whereas the coating lifetimes for machined shim (conventional shim) and diamond-polished shim were similar to 85 min and similar to 70 min, respectively. Further, by comparing the HiPIMS gradient chromium pre-layer between the coating and substrate for the different shims, the study also explained that the quasi-isotropic surface texture of grit-blasted shim is more advantageous for coating-substrate interface adhesion.
10.3390-coatings12121972	-1		In the manufacturing industry, surface structures and surface topographies present at functional areas of the mechanical parts play a vital role in various performance characteristics, such as corrosion resistance, weldability, and wear behaviors, etc. Copper-zinc alloys are extensively used in the manufacturing industry. Laser ablation has the potential to create a variety of surface structures on the ablated substrate. The size and geometry of such structures largely depend on the selection of process parameters and the ablation environment. In the present study, a copper-zinc alloy (95% Cu and 5% Zn) has been laser ablated under different gaseous and magnetic environments to realize a variety of micro-structuring at the ablation surfaces. The effect of plasma plume pressure on the geometry of the structures is deeply investigated through optical emission spectroscopy (OES) and scanning electron microscopy (SEM). By analytically evaluating thermal beta (beta t), directional beta (beta d), and containment radii (Rs) for the plasma of the Cu-Zinc alloy, the validity of magnetic confinement has been proven. In general, five types of microstructures are produced: micro-sized spherical cones, mounted ablated networks, cavities, pores, ridges, and ablation channels with uplifted cones. Moreover, it has been found that, under a magnetic environment, the geometry of the structures is distinct and well-defined compared to those structures achieved when the ablation is carried out without applying a magnetic field.
10.3390-coatings13030660	-1		Copper alloys with a combination of good electrical conductivity and mechanical properties are widely used in automotive electronics, large-scale integrated circuits, and other fields. In this study, a new type of Cu-Ni-Si alloy with added trace elements of Co and Cr was fabricated. Hot compression tests of this alloy at different temperatures and strain rates were conducted using a Gleeble-1500D simulator. Then, the microstructure transformation and precipitation behaviors of the Cu-1.1-Ni-0.7-Co-0.45-Si-0.3Cr alloy were studied during a hot deformation process. The results show that the hot deformation behavior of the Cu-1.1-Ni-0.7-Co-0.45-Si-0.3Cr alloy includes continuous dynamic recrystallization (CDRX) and discontinuous dynamic recrystallization (DDRX). The intensity of the texture in the microstructure is decreased, and the randomness of the texture in the microstructure is increased together with the recrystallization progress. The degree of recrystallization of the new Cu-1.1-Ni-0.7-Co-0.45-Si-0.3Cr alloy is increased when the hot deformation temperature rises. Additionally, the results indicate that there are two types of precipitates which are formed in the alloy during the hot deformation process. These two precipitates can pin dislocations and grain boundaries, and therefore, they significantly improve the hot compression resistance of the Cu-1.1-Ni-0.7-Co-0.45-Si-0.3Cr alloy.
10.3390-coatings13071263	-1		Cu-Cr-Zr alloys reinforced in situ with TiCx nanoparticles were prepared via combustion synthesis and electromagnetic stirring casting. The microstructure of TiCx/Cu-Cr-Zr composites with various contents was analyzed. The microhardness and Brinell hardness of the composites were determined; the average volumetric abrasive wear rate and worn surface of the composites were investigated; and the electrical, thermal conductivity and thermal expansion coefficients of the materials were discussed. The results indicated that the addition of TiCx particles transformed the Cu-Cr-Zr matrix alloy microstructure from a dendritic to an equiaxed crystal, and the grain size was significantly refined as the amount added was increased. The composites with high TiCx content possessed higher hardness and abrasive wear resistance. The addition of TiCx particles reduced the electrical and thermal conductivity and thermal expansion coefficients of the materials.
10.3390-coatings13081414	-1		Ti3AlC2 three-layered ceramics-reinforced copper matrix composites show not only the strength of the copper matrix but also better wear resistance, all while preserving its conductive property and, ultimately, reducing the cost of preparation. However, decomposition in Cu-Ti3AlC2 composites mainly occurs due to the severe interdiffusion of Al and Cu elements from Ti3AlC2 particle-grain boundaries, leading to the formation of TiCx. This work explored a practical method to produce Cu reinforced with a Ti3AlC2 particle which keeps an effective ternary layered structure by adding a nickel element. Results show that the addition of Ni elements results in a microstructure composed of Ti3AlC2, TiCx, NixAl, NixTi, and a Cu(Ni) matrix in the Cu-Ni-Ti3AlC2 composites. As the volume fraction of Ti3AlC2 particles increases, the morphologies change from a finely dispersed reinforcement phase to a continuous network, leading to a reduction in hole number and volume compared to Cu-Ti3AlC2 composites. This reduction is especially significant when the volume fraction of Ti3AlC2 exceeds 50%. The formation of NixAl and NixTi compounds at the grain boundary of the reinforcement phase after Ni element alloying restricts the diffusion of Al elements. The addition of Ni elements improves the mechanical properties of the composites.
10.3390-coatings13091540	2	corrosion; surface; film; electrochemical; films; spectroscopy; layer; current; solution; potential; resistance; composition; x-ray; ions; showed	In recent years, Cu-Sb-based alloys have been considered promising materials for various green applications; for instance, they can serve as catalysts for CO2 reduction, anodic material for metal-ion batteries, and a light-absorbing layer in solar cell. Our research is focused on the electrodeposition of antimony-copper alloy layers with copper content between 18-30 wt%. The layers were observed by scanning, atomic force and transmission electron spectroscopies. Their phase structure, roughness, and hardness were also determined. The electrochemical properties were investigated by using electrochemical impedance spectroscopy and potentiodynamic polarization tests in 0.5 M sulfuric acid. Decreasing the copper content leads to an increase in chemical and morphological heterogeneity and an increase in the roughness from 1.74 to 2.94 & mu;m due to the separation of antimony crystal clusters protruding above the surface but does not significantly affect the hardness and electrochemical behavior of the layers. Copper is recorded only in the form of the Cu2Sb phase. The corrosion current density and potentials of the layers are close to those of pure antimony (about 20 & mu;A cm-2 and about -30 mV vs. Ag/AgCl). The highly porous structure obtained after anodic polarization seems suitable for catalytic purposes.
10.3390-coatings13122041	14	strength; properties; conductivity; electrical; mechanical; cu-; grain; mpa; electrical conductivity; aging; precipitation; phase; mechanical properties; tensile; phases	Laser cladding is a powerful surface treatment technique that can significantly enhance the properties of metal alloys. This study delves into the liquid phase separation behavior of Cu-Fe-Cr alloys under the rapid solidification conditions inherent in laser cladding and evaluates the influence of 4% Mo and 2% B4C additions on the resulting alloy characteristics. The intensive undercooling characteristic of the laser cladding process facilitates the alloy's entry into the liquid-phase immiscibility gap, prompting pronounced phase separation. Our investigation reveals the emergence of Fe-rich regions, exhibiting a variety of shapes, set against a continuous Cu-rich matrix. The incorporation of Mo and B4C was found to modulate the mixing enthalpy and entropy, thereby refining the phase distribution: Mo was observed to prevent the agglomeration of Fe cores, resulting in a dispersion of isolated Fe cores throughout the Cu-rich matrix, while B4C promoted a more uniform compositional distribution. This study further enumerates the enhancements in microhardness, wear resistance, and magnetic properties of the alloys. Notably, the Cu-Fe-Cr-Mo-B4C alloy demonstrated a microhardness exceeding 600 HV, a low coefficient of friction around 0.15, high saturation magnetization, and reduced coercivity. These results underscore the efficacy of laser cladding in tailoring the microstructure and properties of Cu-Fe alloys, providing insights for the controlled manipulation of phase separation to optimize surface characteristics for engineering applications.
10.3390-coatings14010132	2	corrosion; surface; film; electrochemical; films; spectroscopy; layer; current; solution; potential; resistance; composition; x-ray; ions; showed	To investigate the improvements in the resistance of Cu-Ni alloys to surface pitting corrosion, Cu-Ni thin films containing Al were fabricated via DC magnetron sputtering. The morphologies of the fabricated samples were obtained using a scanning electron microscopy, which yielded information on the crystal size and sample surface before and after corrosion tests. X-ray diffraction was employed for the structural characterization of the as-deposited films, and vibrational spectroscopy was used to verify the corrosion products. The corrosion behaviors of the Cu-Ni and Cu-Ni-Al samples were examined using electrochemical polarization and cyclic corrosion tests. The Al co-deposited samples showed a refined crystal size as compared to the Cu-Ni sample, suggesting that they are more susceptible to the formation of a passivation film. The corrosion current density of the Cu-Ni-Al was reduced, and the corrosion potential was lower than that without Al content. The negative shift in the corrosion potential of the Al-containing samples indicates that the Al2O3 film suppressed the cathodic reaction, resulting in a decrease in the corrosion rate. These results are consistent with the cyclic corrosion test results, in which no pitting corrosion is observed in the Cu-Ni-Al sample.
10.3390-coatings14060722	-1		Incorporating expensive alloying elements into bulk steel for corrosion protection is undesirable, considering that only the surfaces are exposed to aggressive environments. Therefore, this work focused on developing and optimizing a new surface functioning technology through in situ observation of thermal interactions between the metallic powders at elevated temperatures. The study revealed that the Cu-Ni powder mixture, with 12.5 wt% Ni, began to melt at 1099.5 degrees C and was fully melted at 1175 degrees C, significantly different from the Cu-Ni solid solution and bulk Cu or Ni. As a result of high-temperature reactions, copper penetration of up to 35 mu m for pure copper and 55 mu m for copper-chromium composite coatings occurred due to liquid metal corrosion. In contrast, the copper-nickel composite coating exhibited a cupronickel solution microstructure with FeNi dendrites and a nickel-rich transition layer. This cupronickel coating, with a chemical composition of 89.3 wt% Cu, 6.2 wt% Ni, and 4.5 wt% Fe, demonstrated uniform thickness, superior surface morphology, and continuous coverage on the steel substrate. Furthermore, the Ni-rich transition layer played a vital role in preventing copper penetration along the grain boundary of the steel matrix while forming a chemical binding between the coating and the substrate. The practicality of the coating was further confirmed through the hot-rolling procedure and subsequent electrochemical corrosion tests, which resulted in a 44% improvement in corrosion resistance.
10.3390-coatings14081017	14	strength; properties; conductivity; electrical; mechanical; cu-; grain; mpa; electrical conductivity; aging; precipitation; phase; mechanical properties; tensile; phases	The impact of introducing trace transition elements on the thermal stability and conductivity of pure copper was examined through metallographic microscopy (OM), transmission electron microscopy (TEM), and electrical conductivity measurements; the interaction between trace transition element and trace impurity element S in the matrix was analyzed. The results show that the addition of trace Ti and trace Cr, Ni, and Ag elements significantly enhances the thermal stability of the pure copper grain size. After high-temperature treatment at 900 degrees C/30 min, the grain sizes of Cu, Cu-Ti-S, and Cu-Cr-Ni-Ag-S were measured and found to be 200.24 mu m, 83.83 mu m, and 31.08 mu m, respectively, thus establishing a thermal stability ranking of Cu-Cr-Ni-Ag-S > Cu-Ti-S > Cu. Furthermore, the conductivities of pure copper remain high even after the addition of trace transition elements, with recorded values for Cu, Cu-Ti-S, and Cu-Cr-Ni-Ag-S of 100.7% IACS, 100.2% IACS, and 98.5% IACS, respectively. The enhancement of thermal stability is primarily attributed to the pinning effect of the TiS and CrS phases, as well as the solid solution dragging of Ni and Ag elements. Trace Ti and Cr elements can react with S impurities to form a hexagonal-structure TiS phase and monoclinic-structure CrS phase, which are non-coherent with the matrix. Notably, the CrS phase is smaller than the TiS phase. In addition, the precipitation of these compounds also reduces the scattering of free electrons by solute atoms, thereby minimizing their impact on the alloy's conductivity.
10.3390-coatings15040381	-1		Copper and its alloys are widely used in marine environments due to their excellent corrosion resistance and thermal conductivity. Cold spray technology can avoid the thermal damage to the underlying material and is suitable for the manufacturing and repair of parts. In this study, Cu coatings were prepared on 304 stainless steel substrates by high-pressure cold spray technology, and the effects of cold spray parameters on the microstructure, mechanical properties, and cavitation resistance were investigated. The coatings (Cu-N21, Cu-N22, and Cu-He) were prepared using distinct cold spray parameters: Cu-N21 and Cu-N22 employed nitrogen gas at 5 MPa/800 degrees C with different nozzle geometries, while Cu-He utilized helium gas at 3 MPa/600 degrees C. The results show that the porosity of the Cu coating prepared by cold spray technology is less than 0.1%. The coating treated with helium gas exhibits a higher bonding strength (81.3 MPa), whereas the coating treated with nitrogen demonstrates greater strain hardening (130-136 HV0.1). XRD results show that no phase change or oxidation occurred for coatings under all cold spraying conditions. After the cavitation test, the mass loss of the Cu coating is significantly less than that of the as-cast copper. The Cu coating surface first develops holes, and with the increase in cavitation time, the hole area begins to increase. However, with prolonged cavitation exposure, the surface of as-cast copper has a large area of holes, and with the increase in cavitation time, the hole growth rate is faster. These observations indicate the cavitation resistance of the Cu coating prepared by cold spray is more than 10 times higher than that of the as-cast copper. This study highlights the potential application of cold spray technology in the preparation of high-performance anti-cavitation copper coatings.
10.3390-coatings15091072	14	strength; properties; conductivity; electrical; mechanical; cu-; grain; mpa; electrical conductivity; aging; precipitation; phase; mechanical properties; tensile; phases	Cu-20Pb-5Sn/45 steel bimetallic composites were prepared using the solid-liquid composite method. The interfacial microstructure, bonding strength, and wear performance were systematically characterized to elucidate the mechanisms governing the solid-solution interface and copper alloy layer wear behavior. The results reveal that mutual diffusion of Cu and Fe forms a metallurgically bonded alpha-(Cu,Ni)/alpha-Fe interface with a diffusion layer thickness of approximately 10.7 mu m and an interfacial shear strength of 227.58 MPa. Under dry sliding conditions, the average coefficient of friction was 0.145, with a wear rate of 7.3665 x 10-6 mm3/(Nm). The alpha-(Cu,Ni) matrix was reinforced by hard Cu3P and Ni-rich phases, which resist frictional shear stresses, while dispersed Pb particles provide self-lubricating properties, while the solid-solution interface hindered dislocation propagation, reducing dislocation pile-up and ensuring stable frictional performance.
10.3390-coatings15091103	14	strength; properties; conductivity; electrical; mechanical; cu-; grain; mpa; electrical conductivity; aging; precipitation; phase; mechanical properties; tensile; phases	Cu-Al-Ni shape memory alloys (SMAs) are attractive for structural and functional applications due to their cost-effectiveness and shape memory behavior. This study systematically investigated the effect of beryllium (Be) addition on the phase stability, microstructure, transformation temperatures, mechanical hardness, corrosion resistance, and wear behavior of Cu-Al-Ni alloys. Alloys with Be contents ranging from 0 to 1.5 wt% were fabricated via arc melting and subjected to thermal treatment. Characterization techniques included dilatometry, X-ray diffraction (XRD), microhardness testing, potentiodynamic polarization, and pin-on-flat wear testing. The results showed that Be additions <= 0.4 wt% stabilized the martensitic beta ' phase, while higher concentrations favored the formation of austenitic beta phase with a BCC structure. Hardness increased with Be content, especially in austenitic samples. Corrosion tests revealed that while the 0.2 wt% Be alloy exhibited the most positive corrosion potential (Ecorr), it also had a higher corrosion rate. Overall, corrosion resistance declined with Be concentrations >= 0.6 wt%. Wear tests demonstrated improved resistance in martensitic alloys, attributed to pseudoplastic deformation. These findings highlight the dual role of Be in modifying phase stability and functional properties, offering useful guidance for designing Cu-based SMAs with tailored performance.
10.3390-coatings8100334	-1		The effect of graphene coating on the growth of grains on bulk copper film was studied. When methane gas is catalytically decomposed on the surface of copper, and a carbon-copper solid solution is formed at high temperature, precipitated carbon on the copper surface forms graphene during rapid cooling through strong sp(2) covalent bonding. The graphene layer can prevent the growth of grains by suppressing the diffusion of copper atoms on the surface, even after continuous heat treatment at high temperatures. The actual size of the copper grains was analyzed in terms of repetitive high-temperature heat treatment processes, and the grain growth process was simulated by using thermodynamic data, such as surface migration energy and the binding energy between copper and carbon. In general, transition metals can induce graphene growth on surfaces because they easily form carbon solid solutions at high temperatures. It is expected that the process of graphene growth will be able to suppress grain growth in transition metals used at high temperatures and could be applied to materials that are prone to thermal fatigue issues such as creep.
10.3390-coatings9010059	2	corrosion; surface; film; electrochemical; films; spectroscopy; layer; current; solution; potential; resistance; composition; x-ray; ions; showed	The aim of this paper is to obtain Cu-Sn composite coatings incorporated with PTFE and TiO2 particles, which have superior antiwear and friction reduction properties. Electrodeposition was carried out in a pyrophosphate electrolyte, and the electrochemical behavior of the plating solutions was estimated. PTFE emulsion and TiO2 sol were prepared and used, of which the average particle sizes were less than 283 and 158 nm, respectively. Then, four different types of coatings, Cu-Sn, Cu-Sn-TiO2, Cu-Sn-PTFE and Cu-Sn-PTFE-TiO2, were electroplated with a pulsed power supply. Their microstructure, composition, microhardness, corrosion resistance and tribological properties were then analyzed and compared in detail. The results show that both PTFE and TiO2 are able to improve coating structure and corrosion resistance, while they have different effects on hardness and tribological properties. However, the presence of both PTFE and TiO2 in the deposited coating leads to a lower friction coefficient of 0.1 and higher wear and corrosion resistance.
10.3390-coatings9020118	-1		Cu-Mn-Dy resistive thin films were prepared on glass and Al2O3 substrates, which was achieved by co-sputtering the Cu-Mn alloy and dysprosium targets. The effects of the addition of dysprosium on the electrical properties and microstructures of annealed Cu-Mn alloy films were investigated. The composition, microstructural and phase evolution of Cu-Mn-Dy films were characterized using field emission scanning electron microscopy, transmission electron microscopy and X-ray diffraction. All Cu-Mn-Dy films showed an amorphous structure when the annealing temperature was set at 300 degrees C. After the annealing temperature was increased to 350 degrees C, the MnO and Cu phases had a significant presence in the Cu-Mn films. However, no MnO phases were observed in Cu-Mn-Dy films at 350 degrees C. Even Cu-Mn-Dy films annealed at 450 degrees C showed no MnO phases. This is because Dy addition can suppress MnO formation. Cu-Mn alloy films with 40% dysprosium addition that were annealed at 300 degrees C exhibited a higher resistivity of 2100 cm with a temperature coefficient of resistance of -85 ppm/degrees C.
10.3390-coatings9050308	-1		In this work, two different approaches were followed to obtain Cu-Al-Ni thin films with shape memory potential. On the one hand, Cu-Ni/Al multilayers were grown by magnetron sputtering at room temperature. To promote diffusion and martensitic/austenitic phase transformation, the multilayers were subjected to subsequent heat treatment at 800 degrees C and quenched in iced water. On the other hand, Cu, Al, and Ni were co-sputtered onto heated MgO (001) substrates held at 700 degrees C. Energy-dispersive X-ray spectroscopy, X-ray diffraction, and transmission electron microscopy analyses were carried out to study the resulting microstructures. In the former method, with the aim of tuning the thin film's composition, and, consequently, the martensitic transformation temperature, the sputtering time and applied power were adjusted. Accordingly, martensitic Cu-14Al-4Ni (wt%) and Cu-13Al-5Ni (wt%) thin films and austenitic Cu-12Al-7Ni (wt%) thin films were obtained. In the latter, in situ heating during film growth led to austenitic Cu-12Al-7Ni (wt%) thin films with a (200) textured growth as a result of the epitaxial relationship MgO(001)[100]/Cu-Al-Ni(001)[110]. Resistance versus temperature measurements were carried out to investigate the shape memory behavior of the austenitic Cu-12Al-7Ni (wt%) thin films produced from the two approaches. While no signs of martensitic transformation were detected in the quenched multilayered thin films, a trend that might be indicative of thermal hysteresis was encountered for the epitaxially grown thin films. In the present work, the differences in the crystallographic structure and the shape memory behavior of the Cu-Al-Ni thin films obtained by the two different preparation approaches are discussed.
10.3390-coatings9110694	-1		To improve the surface wear resistance, plasma nitriding of the prefabricated Cu-Ti films on the C17200 Cu alloy is performed to investigate the effects of the composition of the Cu-Ti films on the microstructure and the mechanical properties of the modified surface. The results firstly showed that obvious microstructure evolution appeared during the thermo-plasma nitriding process, where both the surface morphology of the composed phases and the cross-sectional profiles of the multiphase coatings varied for the three types of films. Small amounts of Ti-N compounds, Be3Ti2Cu, and different types of Cu-Ti intermetallics formed in the multiphase coating after plasma nitriding, which is dependent on the composition of the prefabricated Cu-Ti film. Correspondingly, the surface hardness and the wear resistance of the C17200 Cu substrates were obviously improved, with the obtained adhesive strength of the substrate reaching a satisfactory range.
10.3390-cryst10040312	-1		The softening behavior of a cold-drawn Cu-Cr-In alloy was investigated during annealing between 450 degrees C and 700 degrees C. The properties and microstructure evolution of the alloy were characterized using a microhardness tester, electron back-scatter diffraction, and transmission electron microscopy. Elemental In addition was found to hinder the dislocation movement and delay the recovery and recrystallization of the Cu-Cr-In alloy. The experimental data were analyzed using the Johnson-Mehlv-Avramiv-Kolmogorov model. The activation energy of recrystallization of the 60% cold-drawn Cu0.54Cr0.17In alloy was 188.29 +/- 18.44 kJ/mol, and the recrystallization mechanism of the alloy was attributed mainly to Cu self-diffusion.
10.3390-cryst10121162	-1		The aim of this study is to investigate a characteristic deformation behavior of a precipitation strengthening-type Cu-Ni-Si alloy (Cu-2.4Ni-0.51Si-9.3Zn-0.15Sn-0.13Mg) by microcompression specimens. Three micropillars with a square cross-section of 20 x 20 x 40 mu m(3) were fabricated by focused ion beam (FIB) micromachining apparatus and tested by a machine specially designed for microsized specimens. The three pillars were deformed complicatedly and showed different yield strengths depending on the crystal orientation. The micromechanical tests revealed work hardening by the precipitation clearly. Electron backscattered diffraction analysis of a deformed specimen showed a gradual rotation of grain axis at the grain boundaries after the compression test.
10.3390-cryst11050498	-1		Friction stir alloying (FSA) of commercially pure Cu with Ni, Zn, and Mg is implemented in the current study. Mechanical and microstructural aspects of the successfully fabricated alloy structure have been examined. Energy dispersive X-ray spectroscopy revealed a uniform distribution of alloying elements and coalescence at the atomic level. The compositional and grain size heterogeneity is managed in the stir zone, allowing for microstructural control with FSA. Thus, the present study is essential for the development of novel materials whose fabrication requires temperature well below the melting point of base metals. The alloying process is found to be accompanied by ultra-refined grains, with the smallest grain size being similar to 0.44 mu m. The fabricated alloy managed to retain the FCC phase, and no brittle intermetallic compounds formed, according to X-ray diffraction. The fabricated alloy exhibits maximum and average microhardness enhancements of 18.4% and 6%, respectively. Tensile properties have also been investigated and correlated with microstructural morphology. A shift toward grain bimodality has also been documented, which is a highly sought-after property nowadays, especially to overcome the strength-ductility trade-off.
10.3390-cryst11091113	-1		The microstructure and texture distribution of ultra-high purity Cu-0.1Al alloy target play a key role in the quality of the sputtering film. The Cu-0.1Al alloy sheets were processed by unidirectional (UR) and cross rolling (CR), and X-ray diffraction (XRD), and electron backscatter diffraction (EBSD) technologies were adopted to observe the texture and microstructure evolution. XRD results reveal that the texture types vary greatly in UR and CR due to the change of strain path . As the strain increases to 90%, S texture occupies the most, followed by copper texture in the UR sample, while brass texture dominates the most in the CR sample. Additionally, the orientation density of texture does not increase significantly with the increase of strain but shows a downward trend both in UR and CR modes. EBSD analysis demonstrates that compared with UR, the deformation microstructure in CR is more uniform, and the layer spacing between the deformation bands is smaller, which can reduce the local-region stress concentration. After the completion of recrystallization, the difference in average grain size between the UR and CR-annealed samples is not significant, and the recrystallized grains become much finer with the increase of strain, while more equiaxed grains can be observed in CR-annealed samples.
10.3390-cryst11121505	-1		A three-dimensional finite element method (3D FEM) simulation was carried out using ABAQUS/Explicit software to simulate multi-pass processing by equal-channel angular pressing (ECAP) of a circular cross-sectional workpiece of a Cu-Zr alloy. The effective plastic strain distribution, the strain homogeneity and the occurrence of a steady-state zone in the workpiece were investigated during ECAP processing for up to eight passes. The simulation results show that a strain inhomogeneity was developed in ECAP after one pass due to the formation of a corner gap in the outer corner of the die. The calculations show that the average effective plastic strain and the degree of homogeneity both increase with the number of ECAP passes. Based on the coefficient of variance, a steady-state zone was identified in the middle section of the ECAP workpiece, and this was numerically evaluated as extending over a length of approximately 40 mm along the longitudinal axis for the Cu-Zr alloy.
10.3390-cryst12010097	-1		The crystallographic orientation relationship between alpha and beta phases during the non-equilibrium heat treatment of a Cu-37 wt. % Zn alloy was investigated. With this aim, Cu-37 wt. % Zn alloy plates with a thickness of 2 mm were heated at 810 degrees C for 1 h and then were quenched in water. The microstructure and texture of heat-treated samples were analyzed using optical microscopy and electron backscattered diffraction. By this non-equilibrium heat treatment, beta phase was formed on both the grain boundaries and grain interiors. In addition, the sigma 3 twin boundaries acted as preferred areas for alpha ->beta transformation. The orientation imaging microscopy results revealed a Kurdjumov-Sachs (K-S) orientation relationship between alpha and beta phases. Furthermore, the details of microstructural evolution and texture analysis were discussed.
10.3390-cryst12121754	16	wear; composite; composites; powders; milling; particles; powder; wt; sliding; friction; hardness; matrix; mechanical; surface; properties	A near-equiatomic multi-principal element alloy of Cu40Nb30(TiB2)(20)C-10 with both nano-particle size (14 nm) and micron-particle sizes (-44 mu m) of Nb was designed and made via the spark plasma sintering technique at two different sintered temperatures of 650 degrees C and 700 degrees C with other SPS parameters being constant. The sintering mode, microstructures, microhardness, density, relative density, wear behavior, and corrosion properties of the alloys were investigated and compared to ascertain the best for aerospace applications. The SPS technique was applied to produce the tested samples in this study. The results showed that the alloys with nano-particles of Nb sintered faster, with the lowest wear rate, and their microstructure shows a dendritic configuration with the existence of graphite-rich and niobium-rich nano-segregations in the inter-dendritic areas with the lowest coefficient of friction, Cu-NbTiB2C with nano-particles of Nb sintered at 650 degrees C recorded the highest microhardness value (786.03 HV0.2), and CuNbTiB2C with micro-particles of Nb sintered at 700 degrees C exhibited the best anti-corrosion characteristics in a sulphuric acid environment. The results obtained in this study correspond to the requirements for high-performance engineering materials, which will make the novel materials relevant in the aerospace industry.
10.3390-cryst13020274	-1		Three kinds of Cu-Ni-Al alloys, whose chemical compositions are located in the Cu-rich corner of the isothermal section of the Cu-Ni-Al ternary phase diagram, were prepared by melting and casting firstly, and then solution and aging treatments were carried out. The microstructure was characterized and the competitive formation process of Ni-Al intermetallics were discussed. The results show that there are little amounts of NiAl phase at the grain boundary and needle- or particle-like Ni3Al phase inside the Cu matrix in all the as-cast alloys, although they are in the single-phase area. Solution and aging treatments mainly result in the disappearance and precipitation of Ni3Al phase, but the precipitations during aging are much smaller than those in the as-cast alloys. Thermodynamics and kinetics calculation indicate that the NiAl intermetallic wins out in the solidification process because of its lower change in Gibbs free energy, while Ni3Al phase is first to precipitate during aging due to its lower formation enthalpy and required Al concentration. The most important contribution of this work is that it proves that intermetallics can precipitate from the so-called single-phase zone in the Cu-rich corner of the Cu-Ni-Al phase diagram, which is the necessary prerequisite for the realization of high strength and high electrical conductivity.
10.3390-cryst13111532	-1		In order to explore the mechanism of the influence of Sn contents on the relevant properties of Cu-Sn alloys, the structure, elasticity, electronic, and thermal properties of Cu-Sn alloys doped with different proportions of Sn (3.125 at%, 6.25 at%, and 9.375 at%) were established using the first-principles calculation based on density functional theory. Firstly, their lattice constants and Sn concentration comply with Vegard's Law. From the mixing enthalpy, it can be seen that Sn atoms can be firmly dissolved in the Cu matrix, and the structure is most stable when the Sn content is 3.125 at%. In addition, the introduction of mismatch strain characterized their solid solution strengthening effect. The elastic and electronic properties showed that when the Sn content is 6.25 at%, the Cu-Sn alloy has the best plasticity and the highest elastic anisotropy; when the Sn content is 3.125 at%, the Cu-Sn alloy is the most stable and has stronger bulk and shear modulus, which was mainly due to a stronger Cu-Cu covalent bond. Finally, the Debye temperature, thermal conductivity, and melting point were calculated. It is estimated that the thermal conductivity of Cu-Sn alloy is relatively good when the Sn content is low.
10.3390-cryst15060547	14	strength; properties; conductivity; electrical; mechanical; cu-; grain; mpa; electrical conductivity; aging; precipitation; phase; mechanical properties; tensile; phases	This study addresses critical challenges in manufacturing GRCop-42 Cu alloy (Cu-4Cr-2Nb) components via laser-directed energy deposition (LDED). We systematically establish process-microstructure-property correlation for this alloy, demonstrating that laser power critically governs defect formation and mechanical performance. The alloy exhibited optimal microstructure and properties at a laser power of 2000 W, with a room temperature tensile strength of 319 +/- 6.5 MPa and an elongation of 25.42 +/- 1.9%. The tensile strength in the high-temperature tensile test at 600 degrees C was measured at 98 +/- 3.1 MPa, with an elongation of 15.83 +/- 1.5%. The comprehensive performance reaches the optimal value of the processing window. Through cross-scale characterization techniques, the differences in fracture mechanisms at different temperatures are clarified for the first time: at room temperature, a microporous aggregation-type ductile fracture is observed, with plastic deformation primarily dominated by dislocation slip; in a high-temperature environment, due to the weakening of grain boundary strength, the fracture mode shifts to intergranular fracture, and the deformation mechanism evolves into a synergistic effect of dislocation slip and twinning. The findings of this study not only provide valuable insights into optimizing the LDED process parameters for the GRCop-42 alloy but also shed light on the relationship between its microstructure and mechanical properties under different temperature conditions, offering a solid foundation for the further application of this alloy in complex aerospace components.
10.3390-cryst15060560	14	strength; properties; conductivity; electrical; mechanical; cu-; grain; mpa; electrical conductivity; aging; precipitation; phase; mechanical properties; tensile; phases	This study investigates the tribo-mechanical properties of a modified Cu-Cr-Zr alloy with nickel addition, aimed at enhancing its suitability as a resistance spot welding (RSW) electrode material. Two alloy compositions, designated as Sample A (Cu-0.871%Cr-0.156%Zr) and Sample B (modified with 8.94% Ni), were prepared. Microstructural examination revealed a coarse, mixed equiaxed-columnar grain structure in Sample A, while Sample B exhibited a refined dendritic morphology of about 50 mu m PDAS, due to nickel-induced solute partitioning, improving microhardness from 72.763 HV to 83.981 HV. The wear behavior was evaluated using a pin-on-disc tribometer with a full factorial design, assessing the effects of rotational speed, load, and time on mass loss and surface roughness. Sample A exhibited increased mass loss and roughness with higher loads and speeds, indicating severe wear. In contrast, Sample B showed reduced mass loss and roughness at higher loads, suggesting a polishing effect from plastic deformation. Design of experiments analysis identified load as the dominant factor for mass loss in Sample A, with speed primarily affecting roughness, while in Sample B, load negatively influenced both responses, with speed-time interactions being significant. These findings highlight the nickel-modified alloy's superior wear resistance and hardness, making it a promising candidate for RSW electrodes in high-production environments.
10.3390-cryst15100858	14	strength; properties; conductivity; electrical; mechanical; cu-; grain; mpa; electrical conductivity; aging; precipitation; phase; mechanical properties; tensile; phases	This study systematically investigates the effects of welding current on the macro-morphology, microstructure, mechanical properties, and corrosion resistance of Cu-Mn-Al alloy coatings deposited on 27SiMn steel substrates using Cold Metal Transfer (CMT) technology. The 27SiMn steel is widely applied in coal mining, geology, and engineering equipment due to its high strength and toughness, but its poor corrosion and wear resistance significantly limits service life. To address this issue, a Cu-Mn-Al alloy (high-manganese aluminum bronze) was selected as a cladding material because of its superior combination of mechanical strength, toughness, and excellent corrosion resistance in saline and marine environments. Compared with conventional cladding processes, CMT technology enables low-heat-input deposition, reduces dilution from the substrate, and promotes defect-free coating formation. To the best of our knowledge, this is the first report on the fabrication of Cu-Mn-Al coatings on 27SiMn steel using CMT, aiming to optimize process parameters and establish the relationship between welding current, phase evolution, and coating performance. The experimental results demonstrate that the cladding layer width increases progressively with welding current, whereas the layer height remains relatively stable at approximately 3 mm. At welding currents of 120 A and 150 A, the cladding layer primarily consists of alpha-Cu, kappa II, beta-Cu3Al, and alpha-Cu + kappa III phases. At higher welding currents (180 A and 210 A), the alpha-Cu + kappa III phase disappears, accompanied by the formation of petal-shaped kappa I phase. The peak shear strength (509.49 MPa) is achieved at 120 A, while the maximum average hardness (253 HV) is obtained at 150 A. The 120 A cladding layer demonstrates optimal corrosion resistance. These findings provide new insights into the application of CMT in fabricating Cu-Mn-Al protective coatings on steel and offer theoretical guidance for extending the service life of 27SiMn steel components in aggressive environments.
10.3390-cryst8110435	15	aging; strength; conductivity; electrical conductivity; electrical; mpa; treatment; strengthening; degrees; cu-; cold; precipitation; tensile strength; tensile; iacs	Cu-Ni-Si alloy with a different Co content was prepared by inductive melting and hot rolling. The alloy was solution treated at 950 degrees C for 1.5 h and aged at 450 degrees C, 500 degrees C, and 550 degrees C for different times. The phase diagram calculation and transmission electron microscopy was used to investigate the effect of Co addition on the aging precipitation behavior of the Cu-Ni-Si alloy. The phase transformation kinetics equation was calculated as well. The results show that, with the increase of aging temperature, the two-phase region of Fcc + Ni2Si in the Cu-Ni-Si ternary diagram would get wider. Some NixSiy phases would also form in the Cu-rich isothermal section. The addition of Co would replace part of Ni to form the (Ni, Co)(2)Si phase, which inhibits the spinodal decomposition process of the Cu-Ni-Si alloy during the aging process. The precipitated phase of the Cu-Ni-Si alloy with a high content of the Co element is more likely to grow with the extension of aging time. The phase transformation kinetic equations of the Cu-Ni-Si alloy at 450 degrees C and 500 degrees C showed good agreement with the experimental results. Furthermore, it can be seen from the precipitation kinetic curve the addition of the Co element accelerates precipitation in the aging process.
10.3390-lubricants10110277	-1		In this paper, we present a newly modified machine learning model that employs a long short-term memory (LSTM) neural network model with the golden jackal optimization (GJO) algorithm to predict the tribological performance of Cu-Al2O3 nanocomposites. The modified model was applied to predict the wear rates and coefficient of friction of Cu-Al2O3 nanocomposites that were developed in this study. Electroless coating of Al2O3 nanoparticles with Ag was performed to improve the wettability followed by ball milling and compaction to consolidate the composites. The microstructural, mechanical, and wear properties of the produced composites with different Al2O3 content were characterized. The wear rates and coefficient of friction were evaluated using sliding wear tests at different loads and speeds. From a materials point of view, the manufactured composites with 10% Al2O3 content showed huge enhancement in hardness and wear rates compared to pure copper, reaching 170% and 65%, respectively. The improvement of the properties was due to the excellent mechanical properties of Al2O3, grain refinement, and dislocation movement impedance. The developed model using the LSTM-GJO algorithm showed excellent predictability of the wear rate and coefficient of friction for all the considered composites.
10.3390-lubricants11070291	16	wear; composite; composites; powders; milling; particles; powder; wt; sliding; friction; hardness; matrix; mechanical; surface; properties	Heating of the electrode at the work-piece interface zone in spot welding, leading to degradation of the tip, becomes a significant concern in the high-volume production automotive industry. By recognizing the interrelationship between hardness, wear resistance, and thermal conductivity, the authors emphasize the importance of selecting electrode materials with suitable alloying elements desirable for achieving optimal performance in spot welding applications. This paper studies the wear behaviour of three types of spot-welding electrode materials under dry sliding contact conditions. A pin-on-disc tester was used to investigate Cu-Cd, Cu-Be and Cu-Cr-Zr alloys' wear behaviour under variable parametric load, temperature and time conditions. Taguchi L9 orthogonal array was used to investigate the significance of parameters and their effect on linear wear. The ranking of the parameters was performed using SN ratio analysis. The wear mechanism was also studied using SEM analysis. Abrasive wear was observed at lower loads, while adhesion, oxidation and plastic deformation were observed under high-load and -temperature conditions. This study suggests an alternative to the presently used electrolytic tough pitch (ETP) Cu electrode involving equally good wear-resistance material. However, a detailed investigation on the effect of plasma on the metallurgical characteristics of selected material is suggested.
10.3390-lubricants13070289	14	strength; properties; conductivity; electrical; mechanical; cu-; grain; mpa; electrical conductivity; aging; precipitation; phase; mechanical properties; tensile; phases	Mold copper plates (Cr-Zr-Cu alloy) frequently fail due to severe wear under high-temperature conditions during continuous casting. To solve this problem, Inconel 718 coatings were prepared on the plate surface via laser cladding to enhance its high-temperature wear resistance. The results demonstrate that the coatings exhibit a defect-free structure with metallurgical bonding to the substrate. The coating primarily consists of a gamma-(Fe, Ni, Cr) solid solution and carbides (M23C6 and M6C). Notably, elongated columnar Laves phases and coarse Cr-Mo compounds were distributed along grain boundaries, significantly enhancing the coating's microhardness and high-temperature stability. The coating exhibited an average microhardness of 491.7 HV0.5, which is approximately 6.8 times higher than that of the copper plate. At 400 degrees C, the wear rate of the coating was 4.7 x 10-4 mm3N-1min-1, significantly lower than the substrate's wear rate of 8.86 x 10-4 mm3N-1min-1, which represents only 53% of the substrate's wear rate. The dominant wear mechanisms were adhesive wear, abrasive wear, and oxidative wear. The Inconel 718 coating demonstrates superior hardness and excellent high-temperature wear resistance, effectively improving both the surface properties and service life of mold copper plates.
10.3390-ma10040333	-1		Copper alloys, combined with selective laser melting (SLM) technology, have attracted increasing attention in aerospace engineering, automobile, and medical fields. However, there are some difficulties in SLM forming owing to low laser absorption and excellent thermal conductivity. It is, therefore, necessary to explore a copper alloy in SLM. In this research, manufacturing feasibility and forming properties of Cu-4Sn in SLM were investigated through a systematic experimental approach . Single-track experiments were used to narrow down processing parameter windows. A Greco-Latin square design with orthogonal parameter arrays was employed to control forming qualities of specimens. Analysis of variance was applied to establish statistical relationships, which described the effects of different processing parameters (i.e., laser power, scanning speed, and hatch space) on relative density (RD) and Vickers hardness of specimens. It was found that Cu-4Sn specimens were successfully manufactured by SLM for the first time and both its RD and Vickers hardness were mainly determined by the laser power. The maximum value of RD exceeded 93% theoretical density and the maximum value of Vickers hardness reached 118 HV 0.3/5. The best tensile strength of 316-320 MPa is inferior to that of pressure-processed Cu-4Sn and can be improved further by reducing defects.
10.3390-ma10040415	-1		The dependence of the grain boundary character distribution for a Cu-4 at. % Ti polycrystal alloy (average grain size: 100 mu m) on the nucleation of cellular discontinuous precipitates was systematically investigated. In an alloy over-aged at 723 K, cellular discontinuous precipitates consisted of a terminal Cu solid solution and a stable beta-Cu4Ti lamellae nucleated at grain boundaries. Electron backscatter diffraction analysis revealed that the discontinuous precipitation reaction preferentially occurred at random grain boundaries with a Sigma value of more than 21 according to the coincidence site lattice theory. On the other hand, few cellular discontinuous precipitates nucleated at low-angle and low-Sigma boundaries, particularly twin (Sigma 3) boundaries. These findings suggest that the nucleation of discontinuous precipitates is closely correlated with grain boundary character and structure, and hence energy and/or diffusibility. It should therefore be possible to suppress the discontinuous precipitation reaction through control of the alloy's grain boundary energy, by means of texture control and third elemental addition.
10.3390-ma10040428	2	corrosion; surface; film; electrochemical; films; spectroscopy; layer; current; solution; potential; resistance; composition; x-ray; ions; showed	Co-plating of Cu-Ni coatings by supercritical CO2 (sc-CO2) and conventional electroplating processes was studied in this work. 1,4-butynediol was chosen as the surfactant and the effects of adjusting the surfactant content were described. Although the sc-CO2 process displayed lower current efficiency, it effectively removed excess hydrogen that causes defects on the coating surface, refined grain size, reduced surface roughness, and increased electrochemical resistance. Surface roughness of coatings fabricated by the sc-CO2 process was reduced by an average of 10%, and a maximum of 55%, compared to conventional process at different fabrication parameters. Cu-Ni coatings produced by the sc-CO2 process displayed increased corrosion potential of similar to 0.05 V over Cu-Ni coatings produced by the conventional process, and 0.175 V over pure Cu coatings produced by the conventional process. For coatings similar to 10 mu m thick, internal stress developed from the sc-CO2 process were similar to 20 MPa lower than conventional process. Finally, the preferred crystal orientation of the fabricated coatings remained in the (111) direction regardless of the process used or surfactant content.
10.3390-ma10080919	17	wear; composites; coating; friction; composite; coatings; surface; tribological; properties; wear resistance; resistance; powder; sliding; matrix; wear rate	The TiCp/Cu master alloy was prepared via thermal explosion reaction. Afterwards, the nano-sized TiCp/Cu master alloy was dispersed by electromagnetic stirring casting into the melting Cu-Cr-Zr alloys to fabricate the nano-sized TiCp-reinforced Cu-Cr-Zr composites. Results show that nano-sized TiCp can effectively refine the grain size of Cu-Cr-Zr alloys. The morphologies of grain in Cu-Cr-Zr composites changed from dendritic grain to equiaxed crystal because of the addition and dispersion of nano-sized TiCp. The grain size decreased from 82 to 28 mu m with the nano-sized TiCp content. Compared with Cu-Cr-Zr alloys, the ultimate compressive strength (sigma(UCS)) and yield strength (sigma(0.2)) of 4 wt% TiCp-reinforced Cu-Cr-Zr composites increased by 6.7% and 9.4%, respectively. The wear resistance of the nano-sized TiCp-reinforced Cu-Cr-Zr composites increased with the increasing nano-sized TiCp content. The wear loss of the nano-sized TiCp-reinforced Cu-Cr-Zr composites decreased with the increasing TiCp content under abrasive particles. The eletrical conductivity of Cu-Cr-Zr alloys, 2% and 4% nano-sized TiCp-reinforced Cu-Cr-Zr composites are 64.71% IACS, 56.77% IACS and 52.93% IACS, respectively.
10.3390-ma10121383	-1		Both a Cu-26 wt% Ag (Fe-free) alloy and Cu-26 wt% Ag-0.1 wt% Fe (Fe-doping) alloy were subjected to different heat treatments. We studied the precipitation kinetics of Ag and Cu, microstructure evolution, magnetization, hardness, strength, and electrical resistivity of the two alloys. Fe addition was incapable of changing the precipitation kinetics of Ag and Cu; however, it decreased the size and spacing of rod-shaped Ag precipitates within a Cu matrix, because Fe might affect the elastic strain field and diffusion field, suppressing the nucleation of Ag precipitates. Magnetization curves showed that -Fe precipitates were precipitated out of the Cu matrix, along with Ag precipitates in Fe-doping alloy after heat treatments. The yield strength of the Fe-doping alloy was higher than that of the Fe-free alloy, and the maximum increment was about 41.3%. The electrical conductivity in the aged Fe-doping alloy was up to about 67% IACS (International Annealed Copper Standard). Hardness, strength, and electrical resistivity were intensively discussed, based on the microstructural characterization and solute contributions of both alloys. Our results demonstrated that an increasing fraction of nanoscale -Fe precipitates and decreasing spacing between Ag precipitates resulted in the increasing strength of the Fe-doping alloy.
10.3390-ma11071108	-1		Cu-xNi-5Sn (wt%) alloys with a different Ni content were prepared by a powder metallurgy method. The effect of Ni content on the hardness and yield strength of Cu-xNi-5Sn (wt%) alloys was investigated. The microstructure, composition, and morphology of Cu-xNi-5Sn (wt%) alloys were observed by X-ray diffraction (XRD), scanning electron microscopy (SEM) with energy dispersive spectroscopy (EDS), and cold field emission scanning electron microscope (FESEM), respectively. Results indicate that the hardness and yield strength firstly increase and then decrease with the increase of Ni content and reach up to a maximum when Ni content is 12.5 wt%. Furthermore, the formation of the sandwich structure and needle-like phase is found in the grain, the grain boundary and intragranular precipitates are rich in both the Ni and Sn phase. The formation of the inerratic and suitable lamellar precipitates of sandwich structure and needle-like phase can be responsible for the good mechanical properties of the Cu-12.5Ni-5Sn alloy after aging treatment. The sandwich structure and need-like phase that were observed by FESEM can contribute to clarify the morphology of Cu-Ni-Sn alloys.
10.3390-ma11081394	-1		The precipitation sequence of a Cu-Ni-Be alloy is: alpha-Cu supersaturated solid solution ! Guinier-Preston (G.P.) zones -> metastable gamma '' -> gamma' -> stable gamma (NiBe) phase. The micro-hardness and electrical conductivity during the aging process were measured. The precipitation characteristics and the distribution of the gamma '' phase, under peak aging conditions, were analyzed by X-ray diffraction (XRD), transmission electron microscopy (TEM), selected area diffraction pattern (SADP), and high-resolution transmission electron microscopy (HRTEM). The results show that the orientation relationship of the gamma '' phase/alpha-Cu matrix is: (001)(p)//(001)(alpha); [100](p)//[110](alpha) (p: Precipitates, alpha: alpha-Cu supersaturated solid solution), which is in accordance with the Bain relationship in a FCC/BCC (face centered cubic/body centered cubic) structure, with the unique habit plane being {001}(alpha). While the zone axis is parallel to [001](alpha), three forms of gamma '' phases are distributed on the projection surface at the same time. The (001) reciprocal-lattice positions of gamma '' phase in SADP are diffusely scattered, which is consistent with the variation of the d(001) value of the gamma '' phase. The intra-range variation is related to the distortion of the (001) plane of the gamma '' phase, due to interfacial dislocations and distortion strain fields. The lattice of the gamma '' phase in the HRTEM images was measured as a = b = 0.259 +/- 0.002 nm and c = 0.27-0.32 nm. With the increase of thermal exposure time, the stable gamma phase has a NiBe phase structure (Standard Card Number: PDF#03-1098, a = b = c = 0.261 nm), and the long diffuse scattering spots will transform into single bright spots. The edge dislocation, generated by interfacial mismatch, promotes the formation of an optimal structure of the precipitated phase, which is the priority of growth in the direction of [110](p).
10.3390-ma11081464	-1		In situ micro-TiB2/Cu cermets with a different TiB2 content (40, 50, and 60 vol %) were successfully fabricated by combustion synthesis (CS) and hot press consolidation in Cu-Ti-B systems. In addition, different contents of Cr and Zr were added to the Cu-Ti-B systems. The microstructure, mechanical properties, and abrasive wear properties of the TiB2/Cu cermets were investigated. As the ceramic content increased, the yield strength and compressive strength of the cermets were found to increase, while the strain decreased. An increase in load and abrasive particle size caused the wear volume loss of the TiB2/Cu cermets to increase. When the ceramic content was 60 vol %, the wear resistance of the TiB2/Cu cermets was 3.3 times higher than that of pure copper. The addition of the alloying elements Zr and Cr had a significant effect on the mechanical properties of the cermets. When the Cr content was 5 wt%, the yield strength, ultimate compressive strength, and microhardness of the cermets reached a maximum of 997 MPa, 1183 MPa, and 491 HV, respectively. Correspondingly, when the Zr content was 5 wt%, those three values reached 1764 MPa, 1967 MPa, and 655 HV, respectively, which are 871 MPa, 919 MPa, and 223 HV higher than those of the unalloyed cermets. The wear mechanism of the in-situ TiB2/Cu cermets, and the mechanisms by which the strength and wear resistance were enhanced by the addition of Zr, were preliminarily revealed.
10.3390-ma11091777	-1		The effects of aluminum on the mechanical properties and corrosion behavior in artificial seawater of Cu-Ni-Fe-Mn alloys were investigated. Cu-7Ni-xAl-1Fe-1Mn samples, consisting of 0, 1, 3, 5, and 7 wt% aluminum along with the same contents of other alloying elements (Ni, Fe, and Mn), were prepared. The microstructure of Cu-7Ni-xAl-1Fe-1Mn alloy was analyzed by Transmission Electron Microscopy (TEM), and its corrosion property was tested by an electrochemical system. The results show that the mechanical and corrosion properties of Cu-7Ni-xAl-1Fe-1Mn alloy have an obvious change with the aluminum content. The tensile strength has a peak value of 395 MPa by adding 3 wt% aluminum in the alloy. Moreover, the corrosion rate in artificial seawater of Cu-7Ni-3Al-1Fe-1Mn alloy is 0.0215 mm/a which exhibits a better corrosion resistance than the commercially used UNS C70600. It is confirmed that the second-phase transformation of Cu-7Ni-xAl-1Fe-1Mn alloy follows the sequence of alpha solid solution -> Ni3Al -> Ni3Al + NiAl -> Ni3Al + NiAl3. The electrochemical impedance spectroscopy (EIS) shows that the adding element aluminum in the Cupronickel can improve the corrosion resistance of Cu-7Ni-xAl-1Fe-1Mn alloy.
10.3390-ma12030339	-1		Cu-2.4 wt%V nanocomposite has been prepared by mechanical alloy and vacuum hot-pressed sintering technology. The composites were sintered at 800 degrees C, 850 degrees C, 900 degrees C, and 950 degrees C respectively. The microstructure and properties of composites were investigated. The results show that the Cu-2.4 wt%V composite presents high strength and high electrical conductivity. The composite sintered at 900 degrees C has a microhardness of 205 HV, a yield strength of 404.41 MPa, and an electrical conductivity of 79.5% International Annealed Copper Standard (IACS); the microhardness and yield strength reduce gradually with the increasing consolidation temperature, which is mainly due to the growth of copper grain size. After sintering, copper grain size and V nanoparticle both maintain in nanoscale; the strengthening mechanism is related to grain boundary strengthening and dispersion strengthening, while the grain boundary strengthening mechanism plays the most important role. This study indicates that the addition of small amounts of V element could enhance the copper matrix markedly with the little sacrifice of electrical conductivity.
10.3390-ma12030447	-1		The aim of this work was to study the influence of severe plastic deformation (SPD) on the dissolution of silver particles in Cu-8wt%Ag alloys. In order to obtain different morphologies of silver particles, samples were annealed at 400, 500 and 600 degrees C. Subsequently, the material was subjected to high pressure torsion (HPT) at room temperature. By means of scanning and transmission electron microscopy, as well as X-ray diffraction techniques, it was found that during SPD, the dissolution of second phase was strongly affected by the morphology and volume fraction of the precipitates in the initial state. Small, heterogeneous precipitates of irregular shape dissolved more easily than those of large size, round-shaped and uniform composition. It was also found that HPT led to the increase of solubility limit of silver in the copper matrix as the result of dissolution of the second phase. This unusual phase transition is discussed with respect to diffusion activation energy and mixing enthalpy of the alloying elements.
10.3390-ma12081267	-1		Aluminum bronze is a complex group of copper-based alloys that may include up to 14% aluminum, but lower amounts of nickel and iron are also added, as they differently affect alloy characteristics such as strength, ductility, and corrosion resistance. The phase transformations of nickel aluminum-bronze alloys have been the subject of many studies due to the formations of intermetallics promoted by slow cooling. In the present investigation, quaternary systems of aluminum bronze alloys, specifically Cu-10wt%Al-5wt%Ni-5wt%Fe (hypoeutectoid bronze) and Cu-14wt%Al-5wt%Ni-5wi%Fe (hypereutectoid bronze), were directionally solidified upward under transient heat flow conditions. The experimental parameters measured included solidification thermal parameters such as the tip growth rate (V-L) and cooling rate (T-R), optical microscopy, scanning electron microscopy (SEM) analysis, hardness, and microhardness. We observed that the hardness and microhardness values vary according to the thermal parameters and solidification. We also observed that the Cu-14wt%Al-5wt%Ni-5wi%Fe alloy presented higher hardness values and a more refined structure than the Cu-10wt%Al-5wt%Ni-5wt%Fe alloy. SEM analysis proved the presence of specific intermetallics for each alloy.
10.3390-ma12111869	2	corrosion; surface; film; electrochemical; films; spectroscopy; layer; current; solution; potential; resistance; composition; x-ray; ions; showed	Surface characterization and corrosion behavior of 90/10 copper-nickel alloy in seawater from Xiamen bay at 30 degrees C for 56 days were investigated in this study. The results indicated that the corrosion product layer was mainly a mixture of CuO, Cu2O, and Cu(OH)(2), with a transition to CuCl, CuCl2, and Cu-2(OH)(3)Cl during the corrosion process. However, as corrosion proceeds, the resistance of the product film was reduced due to its heterogeneous and fairly porous structures, which led to local corrosion of the alloy. The corrosion potentials (E-corr) increase while corrosion current densities (I-corr) decrease with time because of the formation of protective oxide film.
10.3390-ma12132076	-1		The effect of the Ni/Si mass ratio and combined thermomechanical treatment on the microstructure and properties of ternary Cu-Ni-Si alloys is discussed systematically. The Cu-Ni-Si alloy with a Ni/Si mass ratio of 4-5 showed good comprehensive properties. Precipitates with disc-like shapes were confirmed as the Ni2Si phase with orthorhombic structure through transmission electron microscopy, high-resolution transmission electron microscopy, and 3D atom probe characterization. After the appropriate thermomechanical treatment, the studied alloy with a Ni/Si mass ratio of 4.2 exhibited excellent mechanical properties: a hardness of 290 HV, tensile strength of 855 MPa, yield strength of 782 MPa, and elongation of 4.5%. Compared with other approaches, the thermomechanical treatment increased the hardness and strength without sacrificing electrical conductivity. Theoretical calculations indicated that the high strength was primarily attributed to the Orowan precipitation strengthening and secondarily ascribed to the work hardening, which were highly consistent with the experimental results. The appropriate Ni/Si mass ratio with a low content of Ni and Si atoms shows high strength and excellent electrical conductivity through combined thermomechanical treatment. This work provides a guideline for the design and preparation of multicomponent Cu-Ni-Si-X alloys with ultrahigh strength and excellent electrical conductivity.
10.3390-ma12132203	17	wear; composites; coating; friction; composite; coatings; surface; tribological; properties; wear resistance; resistance; powder; sliding; matrix; wear rate	In the present work, the mechanical and tribological properties of carbon nanotube (CNT)-reinforced Cu matrix composites featuring 0-1.8 vol% CNTs prepared by spark plasma sintering under dry sliding and boundary lubrication conditions were investigated. The results of microstructure revealed that the bonding interface in Cu/CNT composites was very well established. Additionally, the addition of CNTs has a positive effect on improving the hardness and tensile strength of the composites, while the stress-strain response quasi-static tensile test confirms the same results. CNTs are proved to lead to certain self-lubrication. The addition of CNTs could result in decreased coefficient of friction (COF) and wear rates by reducing adhesive wear under dry sliding conditions, while the oil lubricating film was the major reason for decreased COF under boundary lubrication conditions.
10.3390-ma12152467	-1		Copper-zirconium bulk alloy and Cu-Zr alloy films are prepared by vacuum smelting and magnetron sputtering, respectively, and subsequently annealing is conducted. Results show that Cu-Zr bulk alloy and alloy films exhibit significantly different microstructure evolution behaviors after annealing due to different microstructures and residual stress states. CuxZr alloy compounds disperse at the grain boundary of Cu grains in as-cast and annealed Cu-Zr bulk alloys. However, unlike bulk alloys, a large number of polyhedral Cu particles are formed on the Cu-Zr thin films' surface upon thermal annealing. Kinetically, the residual compressive stress in the Cu-Zr films promotes the formation of Cu particles. The influencing factors and the path for mass transport in the formation of the particles are discussed. The large-specific surface area particles/film composite structure has potential applications in Surface-Enhanced Raman Scattering, catalysis, and other fields.
10.3390-ma12162505	-1		The columnar-grained Cu-Al-Mn shape memory alloys (SMAs), which have good shape memory properties and are prepared by a unidirectional solidification technique, were subjected to a gradient heat treatment under temperatures ranging from 100 to 450 degrees C. After this treatment, the microstructure, hardness, transformation temperature and shape memory properties of these samples could exhibit gradient changing trends, all of which were investigated by optical microscope, scanning electron microscopy (SEM), a Vickers microhardness tester, and a compression machine. The microstructure observation result shows that the acicular bainite-precipitated phase produces from scratch and then grows continuously with the increasing of the heat treatment temperature, finally presenting a graded distribution from one end section to another of the sample. The hardness tests give the samples results also increasing with temperature. Specifically, the change relationship between hardness and the treatment temperature mathematically satisfies dynamic function. In addition, it can be concluded from mechanical tests the compressive elastic-superelastic strain and strength of the samples show gradient variation features. Overall, our experimental investigation indicates that a gradient heat treatment is an effective way to conduct microstructure control or design for the Cu-Al-Mn SMAs, and their graded properties are mainly caused by the different fractions of the bainite phase producing in different local areas after the gradient heat treatment.
10.3390-ma12172772	-1		Effects of C addition on the microstructures of as-cast Cu-Fe-P (mass fraction) alloys were systematically investigated. The results show that C addition can refine the matrix microstructure and make Fe particles finer. The Fe particles observed in both the non-C-alloyed and C-alloyed specimens are alpha-Fe particles, which possess a body-centered cubic (bcc) structure with a Nishiyama-Wassermann orientation relationship with the matrix. C is reported to be an gamma-Fe stabilizer in the literature. The reason for the difference between the phases of Fe particles observed in this study, and that reported in the literature, are finally discussed. Additionally, C addition facilitates the decomposition of the supersaturated solid solution which occurs by the simultaneous precipitation of very fine Fe particles. Such initial decomposition product has an face-centered cubic (fcc) structure with a cube-on-cube orientation relationship with the matrix.
10.3390-ma12182855	-1		The properties and microstructural evolution of quaternary Cu-Ni-Co-Si alloys with different Ni/Co mass ratios are investigated systematically. These alloys exhibit higher mechanical properties when the Ni/Co mass ratio is 1.12-1.95 (NC-4-NC-5) and show excellent electrical conductivity when the Ni/Co mass ratio is 0.05-0.5 (NC-1-NC-3). With an increase in the Ni/Co ratio, the dimension of precipitated phase continues to increase and the grain size also visibly grows and coarsens. At the same time, the precipitation process of the NC-5 alloy is the most adequate, resulting in the highest mechanical properties. In addition, the precipitated phase in the alloys was confirmed to be the (Ni, Co)(2)Si composite phase. The number of Ni2Si phases in the precipitated phase gradually increased, and the Ni atoms exhibited the strongest co-segregation alongside the increasing Ni/Co ratio. Compared with the alloy without a Co element, the addition of Co helped refine the grain size and accelerate the precipitation of the particle phase and purify solute atoms in the matrix, thereby simultaneously improving mechanical properties and conductivity. The present work provides a new method for the development of multicomponent Cu-Ni-Si-Co-X alloys with outstanding comprehensive performance.
10.3390-ma12182990	-1		Copper-chromium alloy film and Cu-Cr bulk alloy were obtained using magnetron sputtering and vacuum smelting. Experimental results indicated that Cu-Cr bulk alloy and alloy films having different residual stress and atomic diffusion exhibit a significant difference in microstructure evolution behaviors after annealing. Numerous polyhedral Cu particles and dendritic Cr particles precipitated on the surface of annealed Cu-Cr alloy film and as-cast Cu-Cr bulk alloy, respectively. Cu particles were formed under the driving of energy and residual stress in the film. The effect of annealing temperature and Cr content on the size and quantity of Cu particles is discussed. Cr particles precipitated on the bulk alloy due to the low solid solubility of Cr in Cu, and the crystallinity of Cu grains promoted the diffusion of Cr atoms. The surface-enhanced Raman scattering (SERS) intensity of the Cu-14.6%Cr alloy film was obviously higher than that of the Cu-14.2%Cr bulk alloy. The particles/film composite structure possessed the appropriate particle number, surface roughness, and interstitial gap, as opposed to the bulk material, to effectively improve SERS enhancement.
10.3390-ma12213462	-1		Both copper and aluminum are widely applicable throughout a variety of industrial and commercial branches, however, joining them in a composite provides the possibility of combining all their advantageous properties in one material. This study investigates uniquely sequenced copper-aluminum clad composite wires, fabricated via rotary swaging technology. The composites were processed at 20 degrees C and 250 degrees C to a diameter of 5 mm. Structural observations and the determination of residual stress within both elements of the swaged wires were performed via electron microscopy; the experimental results were correlated with numerical predictions. As shown in the results, both the applied swaging force and temperature affected the plastic flow, which had a direct influence on residual stress and texture development; the Al-sheath elements exhibited ideal rolling textures, whereas the Cu-wires elements featured ideal shear texture orientation. The grains within both the Al-sheath elements of the 5 mm composite wire were refined down to sub-micron size. Structural restoration also had a positive influence on residual stress.
10.3390-ma12233913	-1		Atomic simulations give a good explanation of the changes in the physical properties of a material. In this work, the tension behaviors of nanopolycrystalline Cu-Ta alloys are investigated through molecular dynamics (MD) simulations, and the influences of several important factors on the mechanical properties of the materials are studied. Firstly, nanopolycrystalline Cu-Ta (10 at%) alloy models with sub-10 nm grains are established by using the method of replacing the grain boundary atoms. Then, the effects of temperature, pressure, and strain rate on the mechanical properties of nanopolycrystalline Cu-Ta alloy are studied, and the elastic modulus and flow strength are obtained. The observations from the simulation results show that the elastic modulus and flow strength increase with the increasing of grain size for sub-10 nm nanopolycrystalline Cu-Ta alloys, and the elastic modulus increases firstly and then stabilizes as the strain rate increases. Finally, according to the evolution of dislocations and twin crystals, the plastic deformation mechanism of nanopolycrystalline Cu-Ta alloy during the stretching process is discussed in depth .
10.3390-ma12244147	-1		The appearance of thin film metallic glasses (TFMGs) is gaining increasing interest because of their unique mechanical and anticorrosion properties and potential engineering applications. In this study, Cu-Zr-Al ternary thin film metallic glasses were fabricated by using DC magnetron sputtering equipment with various target powers. The evolution of the structure was systematically investigated by grazing incidence X-ray diffractometer, scanning electron microscopy, and transmission electron microscopy. The deposition rate increases with the increasing of applied target power. The as-deposited thin films show an amorphous structure. The compositional fluctuations on the nanometer scale indicate the presence of two Cu- and Zr-rich amorphous phases. The electrochemical corrosion measurements indicated that Cu-Zr-Al thin film metallic glasses had good corrosion resistance in the sulfuric acid solution. Nanoindentation results showed that the mechanical deformation was found to be homogenous and reproducible with a high value range for the hardness and modulus.
10.3390-ma13020480	-1		Damping materials have attracted much attention for wide potential applications in the industry. Previous research shows that annealing treatment is an effective and costless way of improving the functional properties of conventional shape memory alloys. However, there are few investigations concerning the annealing effect of the ambient-temperature damping behavior. In this paper, we present the influence of annealing treatment on the martensitic transformation and damping behaviors of Ni55-xCuxMn25Ga20 (x = 0, 2, 4, 6) alloys within the ambient-temperature range. With increasing annealing time, the martensitic transformation temperature and the temperature span of martensitic transformation decrease. Moreover, annealing treatment greatly enhances the twin boundary damping peak of martensite. The X-ray diffraction (XRD) measurement demonstrates that annealing can improve the degree of L2(1) atomic order, which relieves the pinning effects for the twin boundary motion and thus leads to the enhancement of the twin boundary damping of these alloys.
10.3390-ma13030732	15	aging; strength; conductivity; electrical conductivity; electrical; mpa; treatment; strengthening; degrees; cu-; cold; precipitation; tensile strength; tensile; iacs	The microstructure evolution and properties of a Cu-Cr-Ag alloy during continuous extrusion and an aging process were studied by Scanning Electron Microscope (SEM) and Transmission Electron Microscope (TEM). Owing to strong shear deformation that happened during continuous extrusion with working temperatures of 450 to 480 degrees C, a larger number of fine grains were obtained. Both face-centered cubic (FCC) and body-centered cubic (BCC) precipitates simultaneously existed in the matrix when aged for 450 degrees C for 2 h, and the Cr phases with BCC structure had an N-W relationship with the matrix. After continuous extrusion, 60% cold deformation, 875 degrees C x 1 h solid solution treatment, 60% cold deformation, 450 degrees C x 2 h aging treatment, and 70% cold deformation, the Cu-Cr-Ag alloy acquired excellent comprehensive properties: tensile strength of 494.4 MPa, yield strength of 487.6 MPa, and electrical conductivity of 91.4% IACS.
10.3390-ma13092042	8	hot; deformation; strain; strain rate; dynamic; hot deformation; recrystallization; dynamic recrystallization; flow; rate; flow stress; compression; constitutive; degrees; stress	The Cu-1.7Ni-1.4Co-0.65Si (wt%) alloy is hot compressed by a Gleeble-1500D machine under a temperature range of 760 to 970 degrees C and a strain rate range of 0.01 to 10 s(-1). The flow stress increases with the extension of strain rate and decreases with the rising of deformation temperature. The dynamic recrystallization behavior happens during the hot compression deformation process. The hot deformation activation energy of the alloy can be calculated as 468.5 kJ/mol, and the high temperature deformation constitutive equation is confirmed. The hot processing map of the alloy is established on the basis of hot deformation behavior and hot working characteristics. With the optimal thermal deformation conditions of 940 to 970 degrees C and 0.01 to 10 s(-1), the fine equiaxed grain and no holes are found in the matrix, which can provide significant guidance for hot deformation processing technology of Cu-Ni-Co-Si alloy.
10.3390-ma13092062	-1		The mechanical properties of copper alloys containing various ratios of zinc are evaluated using molecular dynamics (MD) simulations to determine the impact of the different zinc concentrations. The modified embedded atom method (MEAM) parameters for copper were established in the 1990s; however, the MEAM potential parameters for zinc, with an axial ratio >1, were recently proposed. In this research, the MD models of the copper alloys with various zinc contents are constructed using the MEAM potential parameters for zinc. Tensile test simulations are also conducted. The strain rate effects of the alloys are evaluated at four different strain rates, and the variations in the tensile strengths and Young's modulus are investigated. The proposed procedures have significant potential applicability for simulating a variety of zinc-containing alloys.
10.3390-ma13102241	6	grain; deformation; strain; strength; dislocation; cu-; tensile; size; ecap; grain size; sfe; ductility; hardening; high; stress	A Cu-1.1%Cr-0.04%Zr (wt%) alloy was processed by severe plastic deformation (SPD) using the equal channel angular pressing (ECAP) technique at room temperature (RT). It was found that when the number of passes increased from one to four, the dislocation density significantly increased by 35% while the crystallite size decreased by 32%. Subsequent rolling at RT did not influence considerably the crystallite size and dislocation density. At the same time, cryorolling at liquid nitrogen temperature yielded a much higher dislocation density. All the samples contained Cr particles with an average size of 1 mu m. Both the size and fraction of the Cr particles did not change during the increase in ECAP passes and the application of rolling after ECAP. The hardness of the severely deformed Cu alloy samples can be well correlated to the dislocation density using the Taylor equation. Heat treatment at 430 degrees C for 30 min in air caused a significant reduction in the dislocation density for all the deformed samples, while the hardness considerably increased. This apparent contradiction can be explained by the solute oxygen hardening, but the annihilation of mobile dislocations during annealing may also contribute to hardening.
10.3390-ma13112602	-1		The aim of this study is to fabricate a Cu-0.5wt%TiB2 composite by mechanical alloying (MA) and spark plasma sintering (SPS). Increasing the milling time, the powders are subjected firstly to a severe flattening process and then to intense welding, which promotes the refinement of TiB2 particles, their uniform dispersion in the metal matrix, and the adhesion between the two constituents. Sintered metal matrix composites (MMC) exhibit density values between 99 and 96%, which are generally decreased by increasing milling time in view of the stronger strain hardening. On the other side, the hardness increases with milling time due to the refinement of TiB2 particles and their improved distribution. The hardness of MMC is three times higher (225 HV0.05) than the starting hardness of atomized copper (90 HV0.05). Tensile tests show a loss of ductility, but ultimate tensile strength has been increased from 276 MPa of atomized copper to 489 MPa of MMC milled for 240 min. The thermal conductivity of MMC is comparable to that of atomized copper (300 W/mK), i.e., much higher than that of the commercial Cu-Be alloy (Uddeholm Moldmax HH, 106 W/mK) typically used for tooling applications.
10.3390-ma13122860	15	aging; strength; conductivity; electrical conductivity; electrical; mpa; treatment; strengthening; degrees; cu-; cold; precipitation; tensile strength; tensile; iacs	Achieving a good match between strength and conductivity is a challenge of the development of the high-performance Cu-Cr-Nb alloy for aerospace and fusion energy. The effect of heat treatment on Cr2Nb phase, strength and conductivity of spark plasma sintered (SPSed) Cu-2Cr-1Nb (at%) alloy was investigated. The results illustrated that Cr2Nb phase of Cu-2Cr-1Nb alloy can be regulated by heat treatment, multi-scale Cr2Nb phase with sizes of 0.10-0.50 mu m, 30-100 nm and less than 30 nm was obtained, and the strength and conductivity were significantly increased after heat treatment at 500 degrees C for 2 h, the room temperature tensile strength and conductivity were 332 MPa and 86.7% IACS, 2.5% and 34.8% higher than those of as-SPSed alloy; the tensile strength at 700 degrees C was 76 MPa. Increasing heat treatment temperature and time, the tensile strength of the alloy was reduced by 1.5%, 4.3% and 12.3% after heat treatment at 500 degrees C, 700 degrees C and 950 degrees C for 72 h . The good match between strength and conductivity of Cu-Cr-Nb alloy was obtained by reducing the content of alloying elements (Cr and Nb) and microstructure regulation. This approach can be used to prepare structural/functional materials with excellent strength and conductivity.
10.3390-ma13143112	-1		The supersaturated Fe in Cu is known to reduce the electrical conductivity of Cu severely. However, the precipitation kinetics of Fe from Cu are sluggish . Alloying is one of the effective ways to accelerate the aging precipitation of Cu-Fe alloys. Nucleation plays an important role in the early stage of aging. The interface property of Cu/gamma-Fe is a key parameter in understanding the nucleation mechanism of gamma-Fe, which can be obviously affected with the addition of alloying elements. In this paper, first principles calculations were carried out to investigate the influence of alloying elements on the interface properties, including the geometric optimizations, interfacial energy, work of adhesion and electronic structure. Based on the previous research, 14 elements including B, Si, P, Al, Ge, S, Mg, Ag, Cd, Sn, In, Sb, Zr and Bi were selected for investigation. Results showed that all these alloying elements tend to concentrate in the Cu matrix with the specific substitution position of the atoms determined by the binding energy between Fe and alloy element (X). The bonding strength of the Cu/gamma-Fe interface will decrease obviously after adding Ag, Mg and Cd, while a drop in interfacial energy of Cu/gamma-Fe will happen when alloyed with Al, B, S, P, Si, Ge, Sn, Zr, Bi, Sb and In. Further study of the electronic structure found that Al and Zr were not effective alloying elements.
10.3390-ma13143186	8	hot; deformation; strain; strain rate; dynamic; hot deformation; recrystallization; dynamic recrystallization; flow; rate; flow stress; compression; constitutive; degrees; stress	Cu-Ni-Si alloys are widely used in lead frames and vacuum devices due to their high electrical conductivity and strength . In this paper, a Cu-Ni-Co-Si-Cr-(Ce) alloy was prepared by vacuum induction melting. Hot compression tests of the Cu-Ni-Co-Si-Cr and Cu-Ni-Co-Si-Cr-Ce alloys were carried out using a Gleeble-1500 simulator at 500-900 degrees C deformation temperatures and 0.001-10 s(-1)strain rates. The texture change was analyzed by electron backscatter diffraction. The fiber component dominated the texture after compression, and the texture intensity was reduced during recrystallization. Moreover, the average misorientation angle phi for Cu-Ni-Co-Si-Cr-Ce (11 degrees) was lower than that of Cu-Ni-Co-Si-Cr (16 degrees) under the same conditions. Processing maps were developed to determine the optimal processing window. The microstructure and precipitates of the Cu-Ni-Co-Si-Cr and Cu-Ni-Co-Si-Cr-Ce alloys were also analyzed. The average grain size of the Cu-Ni-Co-Si-Cr-Ce alloy (48 mu m) was finer than that of the Cu-Ni-Co-Si-Cr alloy (80 mu m). The average size of precipitates in the Cu-Ni-Co-Si-Cr alloy was 73 nm, while that of the Cu-Ni-Co-Si-Cr-Ce alloy was 27 nm. The addition of Ce delayed the occurrence of dynamic recrystallization.
10.3390-ma13153416	-1		The influence of the mass concentration of Ag on properties of Cu-Ni alloys is investigated. The effect of silver addition on the structure and properties of Cu-2Ni-1Si alloys is determined. The scientific aim of this research is to determine how the addition of silver affects the mechanisms of strengthening silver-modified supersaturated, deformed, and aged Cu-2Ni-1Si alloys. The applied thermo-derivative analysis has allowed us to determine a range of the temperature values for the beginning and the end of crystallization, the phases and eutectics, and the effects of the modification on the solid fraction of the solidified alloy. In addition to the crystallization kinetics, the microstructure morphology, mechanical properties under real operating conditions, and the electrical conductivity have also been investigated. Moreover, the conducted research includes the impact of heat treatment and plastic deformation on the alloy structure and considers the type, share, and distribution of the intermetallic phases and structural stresses caused by coherent phases, as well as the effect of dislocations in the reinforcing phases during aging. Electron microscopy (SEM), micro-area analysis (EDS), optical microscopy, hardness measurements, and conductivity of the tested alloys are utilized to comment on these properties.
10.3390-ma13163464	-1		The tensile strength evolution and strengthening mechanism of Cu-Fe in-situ composites were investigated using both experiments and theoretical analysis. Experimentally, the tensile strength evolution of the in-situ composites with a cold deformation strain was studied using the model alloys Cu-11Fe, Cu-14Fe, and Cu-17Fe, and the effect of the strain on the matrix of the in-situ composites was studied using the model alloys Cu-3Fe and Cu-4.3Fe. The tensile strength was related to the microstructure and to the theoretical strengthening mechanisms. Based on these experimental data and theoretical insights, a mathematical model was established for the dependence of the tensile strength on the cold deformation strain. For low cold deformation strains, the strengthening mechanism was mainly work hardening, solid solution, and precipitation strengthening. Tensile strength can be estimated using an improved rule of mixtures. For high cold deformation strains, the strengthening mechanism was mainly filament strengthening. Tensile strength can be estimated using an improved Hall-Petch relation.
10.3390-ma13173739	8	hot; deformation; strain; strain rate; dynamic; hot deformation; recrystallization; dynamic recrystallization; flow; rate; flow stress; compression; constitutive; degrees; stress	In this study, the hot deformation of a Cu-0.55Sn-0.08La (wt%) alloy was studied using a Gleeble-3180 testing machine at deformation temperatures of 400-700 degrees C and various strain rates. The stress-strain curve showed that the hot deformation behavior of the Cu-0.55Sn-0.08La (wt%) alloy was significantly affected by work hardening, dynamic recovery, and dynamic recrystallization. The activation energy Q was 261.649 kJ center dot mol(-1)and hot compression constitutive equation was determined as epsilon=[sinh(0.00651 sigma)](10.2378).exp(33.6656-261.649/RT).The microstructural evolution of the alloy during deformation at 400 degrees C revealed the presence of both slip and shear bands in the grains. At 700 degrees C, dynamic recrystallization grains were observed, but recrystallization was incomplete. In summary, these results provide the theoretical basis for the continuous extrusion process of alloys with promising application prospects in the future.
10.3390-ma13225171	6	grain; deformation; strain; strength; dislocation; cu-; tensile; size; ecap; grain size; sfe; ductility; hardening; high; stress	Recently, the accumulative roll bonding (ARB) technique has made significant progress in the production of various ultrafine-grained (UFG) metals and alloys. In this work, a UFG copper sheet was produced by ARB and subsequent annealing at 300 degrees C for 60 min to optimize strength and ductility. It was found that homogeneous lamellar UFG materials with a thickness of 200-300 nm were formed after six ARB passes. The microhardness and tensile strength of as-ARBed Cu increased, while the ductility and strain hardening decreased with the cumulative deformation strain. The as-ARBed specimens fractured in a macroscopically brittle and microscopically ductile way. After annealing, discontinuous recrystallization occurred in the neighboring interface with high strain energy, which was prior to that in the matrix. The recrystallization rate was enhanced by increasing the cumulative strain. UFG Cu ARBed for six passes after annealing manifested a completely recrystallized microstructure with grain sizes approximately ranging from 5 to 10 mu m. Annealing treatment reduced the microhardness and tensile strength but improved the ductility and strain hardening of UFG Cu. As-annealed UFG-Cu fractured in a ductile mode with dominant dimples and shear zones. Our work advances the industrial-scale production of UFG Cu by exploring a simple and low-cost fabrication technique.
10.3390-ma13235386	15	aging; strength; conductivity; electrical conductivity; electrical; mpa; treatment; strengthening; degrees; cu-; cold; precipitation; tensile strength; tensile; iacs	Cu-Cr-based alloys exhibit excellent electrical conductivity and strength, but their poor thermal stability limits their application in industry. In this paper, Cu-0.2Cr (at. %) and Cu-0.2Cr-0.12Ag (at. %) alloys were prepared to study the effect of Ag on the properties, microstructure, and thermal stability of the Cu-Cr alloy. Microstructure and precipitation were observed by an optical microscope (OM) and a transmission-electron microscope (TEM). After cold-drawing by 99.9% and aging at 450 degrees C for 2 h, the peak hardness and electric conductivity of the Cu-Cr alloy were 120.3 HV and 99.5% IACS, respectively, and those of the Cu-Cr-Ag alloy were 135.8 HV and 98.3% IACS, respectively. The softening temperature of the Cu-Cr alloy was 500 similar to 525 degrees C, and that of the Cu-Cr-Ag alloy was about 550 degrees C. The creep strains of the Cu-Cr and Cu-Cr-Ag alloys at 40 MPa and 400 celcius for 50 h were 0.18% and 0.05%, respectively. Ag elements improved the thermal stability of the Cu-Cr alloy. Recovery and recrystallization occurred before the coarsening of precipitates during the softening process. Ag atoms mainly improved the softening resistance of the alloy by delaying recrystallization, and mainly increased creep resistance by preventing the increase in mobile-dislocation density.
10.3390-ma13235532	-1		In Cu-Cr alloys, the strengthening effects of Cr are severely limited due to the relatively low Cr solid solubility in Cu matrix. In addition, apart from the dissolved Cr, it should be noted that high proportion of Cr in Cu matrix work as the second phase dispersion strengthening. Therefore, it is of great significance to extend the Cr solid solubility and decrease the size of the undissolved Cr phase to nano-structure. In this work, the nano-sized Cu-5 wt% Cr solid solution was achieved through high energy ball milling (HEBM) only for 12 h . The Cr solubility of similar to 1.15 at% was quantitatively calculated based on XRD patterns, which means supersaturated solid solution was realized. Except for the dissolved Cr, the undissolved Cr phase was with nano-sized work as the second phase. Upon milling of the Cu-Cr powders with coarse grains, the crystallite sizes and grain sizes are found to decrease with the milling time, and remain almost unchanged at a steady-state with continued milling. In addition, it was found that the stored energy induced by dislocation density increment and grain size refinement would be high enough to overcome the thermodynamic barrier for the formation of solid solution.
10.3390-ma13245709	-1		Highly-aligned flake graphite (FG) reinforced Cu matrix composites with high thermal conductivity and adaptive coefficient of thermal expansion were successfully prepared via the collaborative process of tape-casting and hot-pressing sintering. To overcome the problem of fragile interface, Zr-Cu alloy powder was introduced instead of pure Zr powder to enhance the interfacial strength, ascribed to the physical-chemical bonding at the Cu-FG interface. The results indicate that the synthetic ZrC as interfacial phase affects the properties of FG/Cu composites. The thermal conductivity reaches the maximum value of 608.7 W/m center dot K (52% higher than pure Cu) with 0.5 wt% Zr. Surprisingly, the negative coefficient of thermal expansion (CTE) in the Z direction is acquired from -7.61 x 10(-6) to -1.1 x 10(-6)/K with 0 to 2 wt% Zr due to the physical mechanism of strain-engineering of the thermal expansion. Moreover, the CTE in X-Y plane with Zr addition is 8 similar to 10 x 10(-6)/K, meeting the requirements of semiconductor materials. Furthermore, the bending strength of the FG/Cu-2 wt% Zr composite is 42% higher than the FG/Cu composite. Combining excellent thermal conductivity with ultralow thermal expansion make the FG/Cu-Zr composites be a highly promising candidate in the electronic packaging field.
10.3390-ma14020368	-1		Cu-Ni-Si alloys are widely used in electrical and electronic industry owing to excellent electrical conductivity and strength . A suitable addition of Co in the Cu-Ni-Si alloys can improve its strength and deteriorate its electrical conductivity. In this work, Cu-Ni-Co-Si-P-Mg alloys with different Co content are employed to investigate the effects of Co on the properties and microstructure. The results showed that Co addition lead to the formation of (Ni, Co)(2)Si precipitates. (Ni, Co)(2)Si precipitate is harder to coarsen than delta-Ni2Si during aging. The larger the Co content in the alloys is, the smaller the precipitates formed is. There exists a threshold content of Co to divide the studied alloys into two groups. One group of theses alloys with <1 wt% Co or Co/Ni ratio <0.56 has the same aging behavior as the Cu-Ni-Si-P-Mg alloy. On the contrary, the time to reach the peak hardness of aging for another group can be obviously delayed and its electrical conductivity decreases slightly with the increase of Co content. It can be attributed to the lower diffusion rate of Co than that of Ni in the Cu matrix. Meanwhile, the Co addition can inhibit the formation of P-enriched Ni-P phase in Co-containing alloys during aging. The as-quenched Cu-1.6Ni-1.2Co-0.65Si-0.1P-0.05Mg alloy can reach 257 HV and 38.7%IACS after aging at 500 degrees C for 3 h, respectively.
10.3390-ma14081996	15	aging; strength; conductivity; electrical conductivity; electrical; mpa; treatment; strengthening; degrees; cu-; cold; precipitation; tensile strength; tensile; iacs	The properties and microstructure evolution of quaternary Cu-Ni-Co-Si alloys with different Ni/Co mass ratios were investigated. The microstructure and morphological characteristics of the precipitates were analyzed by using electron backscatter diffraction (EBSD), transmission electron microscopy (TEM) and high-resolution transmission electron microscopy (HRTEM). The mechanical properties and conductivity of the alloys were significantly improved after the addition of Co. The grains presented an obvious growth trend with an increase in Ni/Co mass ratios, and the appropriate Co accelerated the recrystallization process. The delta-(Ni, Co)(2)Si phases of the Cu-Ni-Co-Si alloys and delta-Ni2Si phases of the Cu-Ni-Si alloys shared the same crystal structure and orientation relationships with the matrix, which had two variant forms: delta(1) and delta(2) phases. The precipitates preferential grew along with the direction of the lowest energy and eventually exhibited two different morphologies. Compared with that of the Cu-Ni-Si alloy, the volume fraction of precipitates in the alloys with Co was significantly improved, accompanied by an increase in the precipitated phase size. The addition of Co promoted the precipitation of the precipitated phase and further purified the matrix. A theoretical calculation was conducted for different strengthening mechanisms, and precipitation strengthening was the key reinforcement mechanism. Moreover, the kinetic equations of both alloys were obtained and coincided well with the experimental results.
10.3390-ma14144007	-1		The effects of rare earth element Sm on the microstructure, mechanical properties, and shape memory effect of the high temperature shape memory alloy, Cu-13.0Al-4.0Ni-xSm (x = 0, 0.2 and 0.5) (wt%), are studied in this work. The results show that the Sm addition reduces the grain size of the Cu-13.0Al-4.0Ni alloy from millimeters to hundreds of microns. The microstructure of the Cu-13.0Al-4.0Ni-xSm alloys are composed of 18R and a face-centered cubic Sm-rich phase at room temperature. In addition, because the addition of the Sm element enhances the fine-grain strengthening effect, the mechanical properties and the shape memory effect of the Cu-13.0Al-4.0Ni alloy were greatly improved. When x = 0.5, the compressive fracture stress and the compressive fracture strain increased from 580 MPa, 10.5% to 1021 MPa, 14.8%, respectively. When the pre-strain is 10%, a reversible strain of 6.3% can be obtained for the Cu-13.0Al-4.0Ni-0.2Sm alloy.
10.3390-ma14164394	4	transformation; martensite; martensitic; phase; shape; beta; memory; shape memory; temperature; temperatures; martensitic transformation; gamma; transformation temperatures; effect; thermal	Using the methods of electron microscopy and X-ray analysis in combination with measurements of the electrical resistance and magnetic susceptibility, the authors have obtained data on the peculiar features of pre-martensitic states and martensitic transformations, as well as subsequent decomposition, in the alloys with shape memory effect of Cu-14wt%Al-3wt%Ni and Cu-13.5wt%Al-3.5wt%Ni. For the first time, we established the microstructure, phase composition, mechanical properties, and microhardness of the alloys obtained in the nanocrystalline state as a result of severe plastic deformation under high pressure torsion and subsequent annealing. A crystallographic model of the martensite nucleation and the rearrangements beta(1)->beta(1)' and beta(1)->gamma(1)' are proposed based on the analysis of the observed tweed contrast and diffuse scattering in the austenite and the internal defects in the substructure of the martensite.
10.3390-ma14164439	1	shape; memory; shape memory; damping; martensite; martensitic; damping capacity; transformation; capacity; strain; superelasticity; temperature; cu-al-mn; shape memory effect; effect	The evolution of the inhomogeneous distribution of the transformation stress (ss) and strain fields with an increasing number of cycles in two differently orientated grains is investigated for the first time using a combined technique of digital image correlation and data-driven identification. The theoretical transformation strains (epsilon(T)) of these two grains with crystal orientations [5 3 26](beta) and [6 5 11] fi along the loading direction are 10.1% and 7.1%, respectively. The grain with lower epsilon(T) has a higher ss initially and a faster decrease in ss compared with the grain with higher epsilon(T). The results show that the grains with higher nu(s) might trigger more dislocations during the martensite transformation, and thus result in greater residual strain and a larger decrease in sigma(s) during subsequent cycles. Grain boundary kinking in bicrystal induces an additional decrease in transformation stress. We conclude that a grain with crystal orientation that has high transformation strain and low transformation stress (with respect to loading direction) will exhibit stable transformation stress, and thus lead to higher functional performance in Cu-based shape memory alloys.
10.3390-ma14174868	16	wear; composite; composites; powders; milling; particles; powder; wt; sliding; friction; hardness; matrix; mechanical; surface; properties	Traditional flood lubrication in machining processes is considered an unsustainable technique. In this paper, the low initial lubrication (LIL) technique is analysed during turning of cupronickel 70/30 alloy, in terms of surface roughness. A tribological analysis has been developed on a pin-on-disk tribometer comparing different lubrication systems, obtaining comparative results of friction and tool wear. It has been found that the tool wear is 73% lower in comparison to flood lubrication. LIL technique shows the ability to reduce the friction coefficient compared to dry machining and leads to improve tool wear in comparison with flood lubrication. The surface integrity evaluation of machined parts finds that the LIL technique can improve the surface roughness under specific machining conditions.
10.3390-ma14174869	-1		Ultrafine-grained (UFG) materials can effectively solve the problem of size effects and improve the mechanical properties due to its ultra-high strength . This paper is dedicated to analyzing the deformation behavior and microstructural evolution of UFG pure copper based on T-shape upsetting test. Experimental results demonstrate that: the edge radius and V-groove angle have significant effects on the rib height and aspect ratio lambda during T-shape upsetting; while the surface roughness has little effect on the forming load in the first stage, but in the second stage the influence becomes significant. The dynamic recrystallization temperature of UFG pure copper is between 200 degrees C and 250 degrees C.
10.3390-ma14185201	-1		In the present study, a Cu-6Ni-6Sn-0.6Si alloy is fabricated through frequency induction melting, then subjected to solution treatment, rolling, and annealing. The phase composition, microstructure evolution, and transition mechanism of the Cu-6Ni-6Sn-0.6Si alloy are researched systematically through simulation calculation and experimental characterization. The ultimate as-annealed sample simultaneously performs with high strength and good ductility according to the uniaxial tensile test results at room temperature. There are amounts of precipitates generated, which are identified as belonging to the DO22 and γ′ phases through the transmission electron microscope (TEM) analysis. The DO22 and γ′ phase precipitates have a significant strengthening effect. Meanwhile, the generation of the common discontinuous precipitation of the gamma phase, which is harmful to the mechanical properties of the copper-nickel-tin alloy, is inhibited mightily during the annealing process, possibly due to the existence of the Ni5Si2 primary phase. Therefore, the as-annealed sample of the Cu-6Ni-6Sn-0.6Si alloy possesses high tensile strength and elongation, which are 967 MPa and 12%, respectively.
10.3390-ma14206179	2	corrosion; surface; film; electrochemical; films; spectroscopy; layer; current; solution; potential; resistance; composition; x-ray; ions; showed	In this work, Cu-Sn-TiO2 composite coatings were electrochemically obtained from a sulfate bath containing 0-10 g/L of TiO2 nanoparticles. The effect of TiO2 particles on kinetics of cathodic electrodeposition has been studied by linear sweep voltammetry and chronopotentiometry. As compared to the Cu-Sn alloy, the Cu-Sn-TiO2 composite coatings show rougher surfaces with TiO2 agglomerates embedded in the metal matrix. The highest average amount of included TiO2 is 1.7 wt%, in the case of the bath containing 5 g/L thereof. Composite coatings showed significantly improved antibacterial properties towards E. coli ATCC 8739 bacteria as compared to the Cu-Sn coatings of the same composition. Such improvement has been connected with the corrosion resistance of the composites studied by linear polarization and electrochemical impedance spectroscopy. In the bacterial media and 3% NaCl solutions, Cu-Sn-TiO2 composite coatings have lower corrosion resistance as compared to Cu-Sn alloys, which is caused by the nonuniformity of the surface.
10.3390-ma14226948	-1		Electron beam additive wire-feed deposition of Cu-7.5wt%Al bronze on a stainless-steel substrate has been carried out at heat input levels 0.21, 0.255, and 0.3 kJ/mm. The microstructures formed at 0.21 kJ/mm were characterized by the presence of both zigzagged columnar and small equiaxed grains with 10% of sigma 3 annealing twin grain boundaries. No equiaxed grains were found in samples obtained at 0.255 and 0.3 kJ/mm. The zigzagged columnar ones were only retained in samples obtained at 0.255 kJ/mm. The fraction of sigma 3 boundaries reduced at higher heat input values to 7 and 4%, respectively. The maximum tensile strength was achieved on samples obtained with 0.21 kJ/mm as tested with a tensile axis perpendicular to the deposited wall's height. More than 100% elongation-to-fracture was achieved when testing the samples obtained at 0.3 kJ/mm (as tested with a tensile axis coinciding with the wall's height).
10.3390-ma14227033	-1		The study is devoted to heavily drawn multicore Cu-18Nb composites of cylindrical and rectangular shapes. The composites were fabricated by the melt-and-deform method, namely, 600 in situ rods of Cu-18%Nb alloy were assembled in a copper shell and cold-drawn to a diameter of 15.4 mm (e = 10.2) and then rolled into a rectangular shape the size of 3 x 5.8 mm (e = 12.5). The specimens were analyzed from the viewpoints of their microstructure, microhardness, and thermal stability. The methods of SEM, TEM, X-ray analysis, and microhardness measurements were applied. It is demonstrated that, at higher strain, the fiber texture 110Nb & PAR; 111Cu & PAR; DD (drawing direction), characteristic of this material, becomes sharper. The distortions of niobium lattice can be observed, namely, the 110 Nb interplanar distance is broadened in longitudinal direction of specimens and compacted in transverse sections. The copper matrix lattice is distorted as well, though its distortions are much less pronounced due to its recrystallization. Evolution of microstructure under annealing consists mainly in the coagulation of ribbon-like Nb filaments and in the vanishing of lattice distortions. The structural changes in Nb filaments start at 300-400 & DEG;C, then develop actively at 600 & DEG;C and cause considerable decrease of strength at 700-800 & DEG;C.
10.3390-ma14237150	-1		Reaching simultaneously high mechanical strength and low electrical resistivity is difficult as both properties are based on similar microstructural mechanisms. In our previous work, a new parameter, the tensile strength-over-electrical resistivity ratio, is proposed to evaluate the matching of the two properties in Cu alloys. A specific ratio of 310 x 10(8) MPa center dot omega(-1)center dot m(-1), independent of the alloy system and thermal history, is obtained from Cu-Ni-Mo alloys, which actually points to the lower limit of prevailing Cu alloys possessing high strength and low resistivity. The present paper explores the origin of this specific ratio by introducing the dual-phase mechanical model of composite materials, assuming that the precipitate particles are mechanically mixed in the Cu solid solution matrix. The strength and resistivity of an alloy are respectively in series and parallel connections to those of the matrix and the precipitate. After ideally matching the contributions from the matrix and the precipitate, the alloy should at least reach half of the resistivity of pure Cu, i.e., 50%IACS, which is the lower limit for industrially accepted highly conductive Cu alloys. Under this condition, the specific 310 ratio is related to the precipitate-over-matrix ratios for strength and resistivity, which are both two times those of pure Cu.
10.3390-ma14247782	-1		Molecular dynamics simulation is one kinds of important methods to research the nanocrystalline materials which is difficult to be studied through experimental characterization. In order to study the effects of Sn content and strain rate on the mechanical properties of nanopolycrystalline Cu-Sn alloy, the tensile simulation of nanopolycrystalline Cu-Sn alloy was carried out by molecular dynamics in the present study. The results demonstrate that the addition of Sn reduces the ductility of Cu-Sn alloy. However, the elastic modulus and tensile strength of Cu-Sn alloy are improved with increasing the Sn content initially, but they will be reduced when the Sn content exceeds 4% and 8%, respectively. Then, strain rate ranges from 1 x 10(9) s(-1) to 5 x 10(9) s(-1) were applied to the Cu-7Sn alloy, the results show that the strain rate influence elastic modulus of nanopolycrystalline Cu-7Sn alloy weakly, but the tensile strength and ductility enhance obviously with increasing the strain rate. Finally, the microstructure evolution of nanopolycrystalline Cu-Sn alloy during the whole tensile process was studied. It is found that the dislocation density in the Cu-Sn alloy reduces with increasing the Sn content. However, high strain rate leads to stacking faults more easily to generate and high dislocation density in the Cu-7Sn alloy.
10.3390-ma15051881	17	wear; composites; coating; friction; composite; coatings; surface; tribological; properties; wear resistance; resistance; powder; sliding; matrix; wear rate	In view of the serious sliding electrical contact performance caused by external vibration and environmental contaminant, a study on the tribological characteristic and contact resistance of Cu alloy was conducted using a self-developed micro-load reciprocating electric contact device. Various glue concentrations (0%, 10%, 30%, and 50%) were prepared with anhydrous ethanol and deposited on the surface of a pure copper block via the deposition method. An external vibration source was installed on the sliding module to achieve vertical vibration. The results indicate that the final contact resistance and coefficient of friction (COF) in direct metal contact are about 0.01 omega and 0.3, respectively. At this time, the wear volume is 2 to 3 orders of magnitude higher than the condition with glue residual. As glue concentration is above 10%, residual glue on the surface of Cu alloy hinders efficient contact between friction pairs, resulting in higher contact resistance. Glue exhibits lubrication, anti-wear, and insulation properties. External vibration causes friction pairs to briefly separate, leading to a lower glue removal capacity than that under non-vibration conditions. The contact resistance with glue addition under vibration conditions is higher than that under non-vibration conditions at 3 x 10(4) cycles. The dominant oxide product is CuO, which has a limited effect on contact resistance.
10.3390-ma15051939	-1		Using milling method, a 0.1 mm flat-bottom sharp knife was used to mill the surface of Cu substrate in a CNC engraving machine to construct the microstructure of rectangular bumps, and rectangular bumps with different sizes and different distances were prepared by changing the distance between cutter tips. After deburring and stearic acid modification, a superhydrophobic Cu surface with excellent mechanical durability and stability was successfully prepared. Through friction and wear experiments, the contact angle of the superhydrophobic Cu surface decreased slightly while retaining excellent corrosion resistance.
10.3390-ma15093352	5	materials; thermal; heat; properties; material; welding; sintering; fusion; strength; laser; heat sink; thermal conductivity; mechanical; sink; manufacturing	Tin-bronze alloys with a tin content of at least 10 wt% have excellent mechanical properties, wear resistance, and corrosion resistance. Among these alloys, Cu-10Sn was investigated in this study for production with the laser powder bed fusion process with a 500W Yb:YAG laser. In particular, a design of experiment (DoE) was developed in order to identify the optimal process parameters to obtain full density, low surface roughness, and high dimensional accuracy. Samples were characterized with Archimedes' method and optical microscopy to determine their final density. It was shown that the first method is fast but not as reliable as the second one. A first mechanical characterization was performed through microhardness tests. Finally, a set of process parameters was identified to produce fully dense samples with low surface roughness and high accuracy. The results showed that the volumetric energy density could represent an approach that is too simplified, therefore limiting the direct correlation with the physical aspects of the process.
10.3390-ma15134501	-1		The microstructure evolution of Cu-Sn-P alloy subjected to hot deformation was researched through electron backscatter diffraction (EBSD) and transmission electron microscope (TEM) in the present study. The results indicated that after hot deformation, grains perpendicular to the force direction were elongated, and mostly became deformed grains, and then exhibited an obvious hardening effect. The Cu-Sn-P alloy could be strain hardened during hot deformation, but, with recrystallization, a softening effect occurred. Changes in dislocation density, textures, and grain sizes play different roles in flow stress behaviors of Cu-Sn-P alloy, and the dislocation density has a more evident effect at low temperature. However, with increase in temperature, recrystallization softening gradually dominates. Low-angle grain boundaries (LABs) account for the majority of hot deformed microstructures of Cu-Sn-P alloy. High dislocation densities in these zones make it easy to initiate the dislocation slipping systems. Deformation is realized through dislocation slipping and the slipping of edge dislocation pairs. The dislocation pile-up zones have high distortion energies, and, thus, elements of diffusion and recrystallization nucleation can occur easily. At different temperatures, the maximum polar density of textures gradually increases, and there are preferred orientations of grains. At 500 degrees C, stacking faults accumulate and promote the growth of twins. The twin growth direction is mainly determined by the migration of high-angle grain boundaries (HABs) and the clustering of high-stress zones.
10.3390-ma15134521	-1		A Cu-Ni-Si alloy containing (Ni + Si) >= 5 wt%, with the addition of Cr, is fabricated by HCCM continuous casting and two steps of aging treatment. The evolution of the microstructures and precipitations, as well as the effect of Cr atoms, is studied in this paper. An excellent combination of mechanical property (hardness HV 250-270) and electrical conductivity (46-47 %IACS) is obtained by the first step aging at 500 degrees C for 0.25 h and the second step aging at 450 degrees C for 1 h . The cold rolling and aging process are directly conducted on the solution treated specimens fabricated by HCCM continuous casting process without hot deformation, since the excellent homogeneity of matrix is obtained by solution treatment with delta-Ni2Si precipitates dissolved. It is found that the formation of discontinuous precipitation is suppressed by the formation of Cr3Si cores of 5-10 nm before the formation delta-Ni2Si. Then, the nucleation and growth of delta-Ni2Si precipitates occurs around the boundaries of these Cr3Si cores, leading to an enhanced nucleation rate. This study provides a promising direction for the design and optimization of Cu-Ni-Si alloys based on the further understanding of the effect of the addition of Cr.
10.3390-ma15155110	-1		In order to realize the high-value utilization of copper slag, a process for preparing Cu-Fe alloy through the reduction of copper slag is proposed. The sulfur in the alloy exists in the form of matte inclusions, which is different from sulfur in molten iron. The reaction of CaO with Cu2S is difficult. It is necessary to add a reducing agent to promote desulfurization. To avoid the introduction of other elements, Fe-Mn and CaC2 additions were used as desulfurizers for the desulfurization of Cu-Fe alloy. The thermodynamics of the desulfurization reaction were calculated and the experimental process was studied. It was found that the Gibbs free energy of desulfurization reactions was negative for Fe-Mn and that CaC2 can reduce the sulfur in the alloy to 0.0013% and 0.0079%, respectively. The desulfurization process affected the shape of copper in the alloy. Part of copper in this alloy exists in the form of nano-copper spheres, and the size of the spheres is found to increase after desulfurization. Reducing agents can facilitate the desulfurization process of stable sulfides.
10.3390-ma15165521	-1		In the present study, Mo was added to Cu-15Ni-8Sn alloy as the fourth element to solve the limitation of service performance of the alloy by composition design. The phase composition, microstructure transformation and mechanical properties of Cu-15Ni-8Sn-xMo (x = 0.3, 0.9, 1.5 wt%) alloy were systematically studied by simulation calculation and experimental characterization. The results show that the addition of Mo can improve the as-cast structure of Cu-15Ni-8Sn alloy and reduce segregation and Cu-Mo phase precipitates on the surface with the increase in Mo contents. During solution treatment, Mo can partially dissolve into the matrix, which may be the key to improving the properties of the alloy. Furthermore, the discontinuous precipitation of Sn can be effectively inhibited by adding the appropriate amount of Mo to Cu-15Ni-8Sn alloy, and the hardness of alloy does not decrease greatly after a long-time aging treatment. When Mo content is 0.9 wt%, the alloy reaches the peak hardness of 384 HV at 4 h of aging. These results provide new ideas for composition optimization of Cu-15Ni-8Sn alloy.
10.3390-ma15165745	6	grain; deformation; strain; strength; dislocation; cu-; tensile; size; ecap; grain size; sfe; ductility; hardening; high; stress	The effect of severe plastic deformation by the conforming process of equal channel angular extrusion (ECAE-Conform) followed by cold rolling on the microstructures developed in a Cu-0.1Cr-0.1Zr alloy was investigated. Following the ECAE-Conform of 1 to 8 passes (corresponding strains were 0.8 to 6.4) cold rolling to a total strain of 4 was accompanied by substantial grain refinement and strengthening. An average grain size tended to approach 160 nm with an increase in the rolling reduction. An increase in the ECAE-Conform strain promoted the grain refinement during subsequent cold rolling. The fraction of the ultrafine grains with a size of 160 nm after cold rolling to a strain of 4 increased from 0.12 to 0.52 as the number of ECAE-Conform passes increased from 1 to 8. Correspondingly, the yield strength increased above 550 MPa. The strengthening could be expressed by a Hall-Petch type relationship with a grain size strengthening factor of 0.11 MPa m(0.5).
10.3390-ma15165750	-1		A Cu-15Fe alloy was fabricated using a powder metallurgy (PM) route, with the addition of different solid lubricants (i.e., paraffin wax (PW) and stearic acid (SA) as well as their composites (PW+SA)). Green compacts were produced via cold compaction at different pressure levels of 50 MPa, 200 MPa, and 350 MPa, then sintered for 60 min under vacuum at 1050 degrees C. The systematic evolution of the densification, porosity, and pore-size behavior were studied. Vickers Hardness Tests were used to measure hardness. The analysis of the morphological alterations was performed using scanning electron microscopy (SEM) and X-ray diffraction (XRD) techniques. Moreover, under dry sliding conditions, pin-on-disk wear tests were conducted in order to determine tribological properties such as the coefficient of friction (mu), specific wear rate (K), and friction temperature gain. Results revealed that the lubrication process and compaction pressure play a crucial role in defining the characteristics of the final compact. Higher sintered densities and hardnesses were achieved at 50 MPa when PW was used as a solid lubricant, and became reduced as the compaction pressure increased. In contrast, in the case of SA, higher sintered densities and hardnesses were obtained at a compaction pressure of 350 MPa, and increased with increasing pressure. Moreover, PW samples exhibited lower coefficients of friction and wear properties. The addition of SA improves the wear loss of friction materials as well as their coefficients of friction. Compared to blank and PW samples, SA samples show a nearly 50% reduction in wear rate.
10.3390-ma15186284	-1		Shape memory alloys (SMAs) are functional materials that are being applied in practically all industries, from aerospace to biomedical sectors, and at present the scientific and technologic communities are looking to gain the advantages offered by the new processing technologies of additive manufacturing (AM). However, the use of AM to produce functional materials, like SMAs, constitutes a real challenge due to the particularly well controlled microstructure required to exhibit the functional property of shape memory. In the present work, the design of the complete AM processing route, from powder atomization to laser powder bed fusion for AM and hot isostatic pressing (HIP), is approached for Cu-Al-Ni SMAs. The microstructure of the different processing states is characterized in relationship with the processing parameters. The thermal martensitic transformation, responsible for the functional properties, is analyzed in a comparative way for each one of the different processed samples. The present results demonstrate that a final post-processing thermal treatment to control the microstructure is crucial to obtain the expected functional properties. Finally, it is demonstrated that using the designed processing route of laser powder bed fusion followed by a post-processing HIP and a final specific thermal treatment, a satisfactory shape memory behavior can be obtained in Cu-Al-Ni SMAs, paving the road for further applications.
10.3390-ma15196777	17	wear; composites; coating; friction; composite; coatings; surface; tribological; properties; wear resistance; resistance; powder; sliding; matrix; wear rate	With the use of electrolytic Cu powder, Zr powder, Si powder and nickel-coated B4C powder as cladding powders, in-situ synthesized ZrB2-SiC reinforced copper matrix composite coatings were prepared by laser cladding on the surface of the copper substrate to improve the surface hardness and wear resistance. Under the condition of a laser energy density at 60 kJ/cm(2), the macroscopic surface of the composite coating was continuously flat. The microstructure and phase of the cladding coating were analyzed by means of XRD and SEM. The reinforcements with nano-scale particle and micron-scale needle-like structures were in-situ synthesized in the cladding coating, and the content of the reinforcement phase decreased slightly from the coating surface to the substrate. The phase analysis results showed that the reinforcements included ZrB2 and SiC. When the content of the reinforcement was increased to 30 wt%, microhardness also increased from 48 HV0.2 to 309 HV0.2, which was about 5.6 times that of the copper matrix. The wear resistance of the composite coatings was characterized by current-carrying wear tests. By keeping the sliding speed and load constant, the wear rate decreased with an increase in the reinforcement content, and the wear mechanism changed from adhesive wear to abrasive wear. The wear rate of the composite coating with the current was higher than that without the current due to its electric ablation and high temperature.
10.3390-ma15196950	-1		Reducing the local stress in the vicinity of the grain boundaries is a favorable way to improve the super-elastic properties of super-elastic alloys. The crystal plasticity finite element method (CPFEM) was applied in this study to simulate the deformation behavior and local stress of a super-elastic Cu-8Al-11Mn (wt%) alloy containing single grains with various orientations, columnar grains with different misorientation angles, and tri-crystals with distinct grain boundary morphologies. The results indicated that the stress distribution of single grains presented obvious orientation dependence during deformation. Uniformly distributed stress was observed in grains with orientations of 0 degrees and 90 degrees when more slip systems were activated during deformation. With the increase in the misorientation angles of columnar grains, the stresses in the vicinity of the grain boundaries increased, which was related to the difference in the shear stress of the slip systems in adjacent grains. When the difference in the shear stress of the slip systems in two adjacent grains was large, a local stress concentration formed in the vicinity of the grain boundary. Compared with the triple-junction grain boundaries, the local stresses of the straight and vertical grain boundaries were smaller, which was closely related to the number of activated slip systems on both sides of the grain boundary. The above results were obtained experimentally and could be used to design super-elastic alloys with high performance.
10.3390-ma15217563	-1		Efficient and power-dense electrical machines are critical in driving the next generation of green energy technologies for many industries including automotive, aerospace and energy. However, one of the primary requirements to enable this is the fabrication of compact custom windings with optimised materials and geometries. Electrical machine windings rely on highly electrically conductive materials, and therefore, the Additive Manufacturing (AM) of custom copper (Cu) and silver (Ag) windings offers opportunities to simultaneously improve efficiency through optimised materials, custom geometries and topology and thermal management through integrated cooling strategies. Laser Powder Bed Fusion (L-PBF) is the most mature AM technology for metals, however, laser processing highly reflective and conductive metals such as Cu and Ag is highly challenging due to insufficient energy absorption. In this regard, this study details the 400 W L-PBF processing of high-purity Cu, Ag and Cu-Ag alloys and the resultant electrical conductivity performance. Six Cu and Ag material variants are investigated in four comparative studies characterising the influence of material composition, powder recoating, laser exposure and electropolishing. The highest density and electrical conductivity achieved was 88% and 73% IACS, respectively. To aid in the application of electrical insulation coatings, electropolishing parameters are established to improve surface roughness. Finally, proof-of-concept electrical machine coils are fabricated, highlighting the potential for 400 W L-PBF processing of Cu and Ag, extending the current state of the art.
10.3390-ma15217605	15	aging; strength; conductivity; electrical conductivity; electrical; mpa; treatment; strengthening; degrees; cu-; cold; precipitation; tensile strength; tensile; iacs	The Cu-1.0% Cr-0.1% Zr alloy in a solid solution state was investigated by ageing treatments at different temperatures and holding times. The structure and performance were characterized and tested by using X-ray diffraction (XRD), a transmission electron microscope (TEM), a universal material testing machine, and an eddy conductivity detector. The influence laws of ageing temperature and the holding time on the structures and properties of the Cu-Cr-Zr alloy were analyzed. Results demonstrated that, with the increase in ageing temperature and holding time, the percentage and size of the Cr precipitated phase increased, and the dislocation density decreased. The tensile strength first increased to the peak value and then decreased. The electrical conductivity increased and the amplitude decreased. The tensile strength of the alloy reached the peak (359 +/- 2 MPa) after ageing at 450 degrees C for 60 min, and the electrical conductivity was 91.9 +/- 0.7% IACS. In addition, in the ageing precipitation process, the chromium precipitated phase had face-centered cubic structure (FCC) and body-centered cubic structure (BCC) structures, and the FCC Cr phase can be transformed into a BCC Cr phase. FCC Cr, BCC Cr, and Cu3Zr precipitation phases maintained different orientation relationships with the Cu substrate.
10.3390-ma15228002	-1		To improve the wear resistance and fatigue life of Cu alloys, surface modification by combining the magnetron sputtering of Ti film followed by vacuum thermal diffusion is always applied, where the structure and composition of the fabricated film play a determinant role on the mechanical properties. In the present work, the evolution of the layered structure and the element distribution of the formed multi-phases coating on C17200 Cu alloy are investigated by mathematical calculation based on Fick's law, and the experimental verification by the thermal diffusion of the gradient Cu-Ti film was undertaken under different temperatures and durations. The results show that the layered structure of the fabricated coating is dependent on the Cu-Ti atom concentration, the increasing time and the temperature, where a single or stratified layer is formed due to the generated Cu-Ti intermetallics for the inter-diffusion between the Cu and Ti atoms. The atom distribution by the proposed simulation method based on Fick's law corresponds to the experimental results, which can be applied to designing the structure of the modification layer.
10.3390-ma15228042	15	aging; strength; conductivity; electrical conductivity; electrical; mpa; treatment; strengthening; degrees; cu-; cold; precipitation; tensile strength; tensile; iacs	Cu-Ti alloys were strengthened by beta'-Cu4Ti metastable precipitation during aging. With the extension of the aging time, the beta'-Cu4Ti metastable phase transformed into the equilibrium beta-Cu4Ti phase. The Cu-3.5 wt% Ti(Cu-4.6 at% Ti) alloys with different processing were aged at different temperatures for various times after solution treatment at 880 degrees C for 1 h . The electrical conductivity of samples under different heat treatments had shown an upward trend as time increased during aging, but the hardness reached the peak value and then decreased. The hardness and electrical conductivity of the samples with 70% deformation after aging are higher tha n the samples without deformation. Deformation after aging would cause the metastable phase to dissolve into a matrix. The best combination value of conductivity and hardness is 13.88% IACS and 340.78 HV, and the optimal heat treatment is 500 degrees C for 2 h + 70% deformation + 450 degrees C for 2 h .
10.3390-ma15248724	15	aging; strength; conductivity; electrical conductivity; electrical; mpa; treatment; strengthening; degrees; cu-; cold; precipitation; tensile strength; tensile; iacs	Cu-Ni-Si alloy is the key raw material for the lead frame of large integrated circuits. The disordered grain orientation of alloy billet, high hardening rate, residual stress, and poor surface quality of cold working strips seriously affect its processability. In order to improve the cold-working properties of Cu-Ni-Si alloy, two kinds of C70250 copper alloy strips were produced through hot mold continuous casting (HMCC) and cold mold continuous casting (CMCC) technology. The effects of solidified microstructure on the cold-working deformation behavior, mechanical properties, and residual stress of the alloy were studied. The results show that C70250 copper alloys with columnar grain and equiaxed grain were prepared through HMCC and CMCC. After a 98% reduction in cold rolling, columnar grain strip surface quality was very good, and the elongation was still as high as 3.2%, which is 2.9 times that of equiaxed grain alloy. The residual stress of equiaxed grain strips reached 363 MPa, which is 2.7 times that of columnar grain strips. During the cold rolling process, equiaxed grain strips are prone to cause intersecting plane dislocations, stacking faults, shear bands, and grain breakage during large deformation cold rolling. The columnar grain strip causes parallel plane dislocations, stacking faults, and shearbands. Furthermore, the deformation structure was found to be uniform, and, ultimately, the alloy formed a fibrous structure. Therefore, the elongation and latter distortion of columnar grain strips improved after being put through large deformation cold rolling, which greatly reduced residual stress.
10.3390-ma15248905	5	materials; thermal; heat; properties; material; welding; sintering; fusion; strength; laser; heat sink; thermal conductivity; mechanical; sink; manufacturing	Aluminium bronzes are widely used in various industries because of their unique properties, a combination of high strength, wear resistance, and corrosion resistance in aggressive environments, including seawater. In this study, the subject of comprehensive experimental research was Cu-10Al-5Fe iron-aluminium bronze (IAB) with beta-transformation, received in the form of hot-rolled bars. The effects of different heat treatments (HT) and severe surface plastic deformation (SPD), conducted by diamond burnishing (DB) on the microstructure, surface integrity (SI), mechanical properties, low- and mega-cycle fatigue strength, and dry sliding wear resistance, were determined. Based on quantitative indicators, the applied heat treatments in combination with severe SPD were compared. Thus, the integral efficiency of the heat treatments was evaluated, and the heat treatments were correlated with the resulting properties and operational behaviour of Cu-10Al-5Fe IAB. For example, if the component is designed for rotational bending conditions, the combination of quenching at 920 degrees C in water, subsequent tempering at 300 degrees C for three hours, and DB provides maximum fatigue strength in both low-cycle and mega-cycle fatigue applications.
10.3390-ma16010105	6	grain; deformation; strain; strength; dislocation; cu-; tensile; size; ecap; grain size; sfe; ductility; hardening; high; stress	A study of the effect of rotary swaging (RS) on the microstructure and properties of the pre-extruded and pre-quenched Cu-0.5%Cr-0.08%Zr alloy was performed. RS leads to the formation of an ultrafine-grained (UFG) microstructure. UFG structure formation caused by RS increases the ultimate tensile strength (UTS) up to 443 +/- 5 MPa and 597 +/- 9 MPa for pre-quenched and pre-extruded alloys, respectively. Additionally, the reduction in ductility occurs after RS. It should be noted that UTS is increased for a pre-quenched alloy, while the strength of a pre-extruded alloy is dropped. The growth of UTS for the pre-quenched alloy is associated with the precipitation of fine Cr particles, whereas the recovery processes in the pre-extruded alloy induce the reduction in its UTS. An additional advantage of RS is an increase in the fatigue limit of the pre-quenched alloy up to 265 MPa, and of the pre-extruded alloy up to 345 MPa. The combination of extrusion and RS allows for the increase of the UTS of the Cu-0.5%Cr-0.08%Zr alloy up to 597 +/- 9 MPa, while the levels of ductility and electrical conductivity are 10.9 +/- 0.9% and 82.0 +/- 1.7% IACS, respectively.
10.3390-ma16010424	-1		A Cu-1.79Ti-0.39Cr-0.1Mg (wt%) alloy was prepared by a vacuum induction melting furnace in a high-purity argon atmosphere. The effects of room temperature rolling and cryogenic rolling on the microstructure, textures, and mechanical properties of the alloy were investigated by means of electron backscatter diffraction, transmission electron microscopy, and X-ray diffraction. The results show that the hardness of the cryogenically rolled alloy is 18-30 HV higher than that of the room temperature rolled alloy at any tested rolling reduction. The yield strength and tensile strength of the alloy cryogenically rolled by 90% reduction are 723 MPa and 796 MPa, respectively. With the increase of rolling reduction, the orientation density of the Cube texture decreases, while the Brass texture increases. The Brass texture is preferred especially during the cryogenic rolling, suggesting that the cross-slip is inhibited at the cryogenic temperature. The dislocation densities of Cu-Ti-Cr-Mg alloy increase significantly during the deformation, finally reaching 23.03 x 10(-14) m(-2) and 29.98 x 10(-14) m(-2) after a 90% reduction for the room temperature rolled and cryogenically rolled alloys, respectively. This difference could be attributed to the impediment effect of cryogenic temperature on dynamic recovery and dynamic recrystallization. The cryogenic temperature promotes the formation of the dislocation and the nano-twins, leading to the improvement of the mechanical properties of the alloy.
10.3390-ma16020815	-1		The purpose of this paper is to investigate the fatigue properties of C17200 alloy under the condition of quenching aging heat treatment at high temperatures, and to provide a design reference for its application in a certain temperature range. For this purpose, the tensile and rotary bending fatigue (RBF) tests were carried out at different temperatures (25 degrees C, 150 degrees C, 350 degrees C, and 450 degrees C). The tensile strength was obtained, and relationships between the applied bending stress levels and the number of fatigue fracture cycles were fitted to the stress-life (S-N) curves, and the related equations were determined. The fractured surfaces were observed and analyzed by a scanning electron microscopy (SEM). The results show that the RBF fatigue performance of C17200 alloy specimens is decreased with the increase in test temperature. When the temperature is below 350 degrees C, the performance degradation amplitudes of mechanical properties and RBF fatigue resistance are at a low level. However, compared to the RBF fatigue strength of 1 x 10(7) cycles at 25 degrees C, it is decreased by 38.4% when the temperature reaches 450 degrees C. It is found that the fatigue failure type of C17200 alloy belongs to surface defect initiation. Below 350 degrees C, the surface roughness of the fatigue fracture is higher, which is similar to the brittle fracture, so the boundary of the fracture regions is not obvious. At 450 degrees C, due to the further increase in temperature, oxidation occurs on the fracture surface, and the boundary of typical fatigue zone is obvious.
10.3390-ma16030922	-1		The peculiarities of Ni and Fe diffusion in polycrystalline Cu and Cu-Fe alloys at a 650-750 degrees C temperature range were studied. It was shown that the bulk diffusion coefficients were in a good agreement with the available literature data obtained for different temperature concentration ranges. The obtained values of the Ni GB diffusion triple product could be described as s delta D-b=8.8x10(-13)xexp(-165 kJmol(-1)/RT)m(3)s(-1). The obtained values were an order of magnitude less than the values obtained by the radiotracer method. This fact was explained by the negative segregation of Ni at the Cu GB. A stronger negative segregation of Fe in the copper GB reduced the penetration depth of iron along the GB because of an additional (negative) driving force; this explained why there was no advanced grain boundary diffusion. Another peculiarity of the Fe diffusion that was confirmed was the significant supersaturation of the Cu-based solid solution near the Fe/Cu interface.
10.3390-ma16030936	-1		In this study, hard wear-resistant Ti-Si-C coatings were deposited on Cu-Cr materials to improve their performance as sliding electrical contact materials. A ceramic disk composed of Ti3SiC2 and TiC phases was used as a target for DC magnetron sputtering to deposit the coatings. The influence of the power supplied to the magnetron on the chemical composition, structure, and friction coefficient of the coatings was examined. The coatings demonstrated high hardness (23-25 GPa), low wear rate (1-3 x 10(-5) mm(3)/N/m) and electrical resistance (300 mu Ohm center dot cm), and fair resistance to electroerosion. The coating deposited at 450 W for 30 min displayed optimal properties for protecting the Cu-Cr alloy from the arc effect.
10.3390-ma16031252	-1		Grain refinement has been found to be an effective method for simultaneously enhancing strength and toughness. To avoid the sharp coarsening of grains in Cu-Ni-Sn alloys during solution treatment and thereby overcoming the tradeoff between strength and ductility, this work attempted to modify the composition and improve the thermal stability of the fine-grained structure in Cu-Ni-Sn alloys. The grain growth behavior during a solution treatment of the Cu-15Ni-8Sn alloys with/without Si and Ti additions was systematically investigated. The result reveals that compared to the grain size of 146 mu m in the based alloy (without trace additions) after solution processing at 1073 K for 2 h, the fine-grained structure with a size below 20 mu m is maintained owing to the benefit from Si and Ti addition. It was observed that the addition of Si and Ti offer the inhibition effect on the dissolution of the gamma phase and Ni16Si7Ti6 particles after solution treatment. The grain boundary movement is severely hindered by these two aspects: the pinning effect from these particles, and the drag effect induced by additional solute atoms. Based on the analysis of grain growth kinetics, the activation energy of grain growth is increased from 156 kJ/mol to 353 kJ/mol with the addition of Si and Ti.
10.3390-ma16041441	-1		By assimilating shape memory alloys with mathematical multifractal-type objects, a theoretical model based on Scale Relativity Theory in the form of The Multifractal Theory of Motion, in order to explain the mechanical behavior of such material, is proposed. The model is validated by analyzing the mechanical behavior of Cu-Al-Zn shape memory alloy with various chemical compositions. More precisely, the multifractal tunnel effect can mime the mechanical hysteresis of such a material, a situation in which a direct correspondence for several mechanical properties of Cu-Al-Zn is highlighted (the chemical composition can be correlated with the shapes of the curves controlled through the multifractality degree, while the areas delimited by the same curves can be correlated with the multifractal specific potential, as a measure of the mechanical memory degree).
10.3390-ma16041445	8	hot; deformation; strain; strain rate; dynamic; hot deformation; recrystallization; dynamic recrystallization; flow; rate; flow stress; compression; constitutive; degrees; stress	Cu-9Ni-6Sn alloys have received widespread attention due to their good mechanical properties and resistance to stress relaxation in the electronic and electrical industries. The hot compression deformation behaviors of the Cu-9Ni-6Sn-0.3Mn-0.2Zn alloy were investigated using the Gleeble-3500 thermal simulator at a temperature range of 700-900 degrees C and a strain rate range of 0.001-1 s(-1). The microstructural evolution of the Cu-9Ni-6Sn alloy during hot compression was studied by means of an optical microscope and a scanning electron microscope. The constitutive equation of hot compression of the alloy was constructed by peak flow stress, and the corresponding 3D hot processing maps were plotted. The results showed that the peak flow stress decreased with the increase in the compression temperature and the decrease in the strain rate. The hot deformation activation energy was calculated as 243.67 kJ/mol by the Arrhenius equation, and the optimum deformation parameters for the alloy were 740-760 degrees C and 840-900 degrees C with a strain rate of 0.001 similar to 0.01 s(-1). According to Deform-3D finite element simulation results, the distribution of the equivalent strain field in the hot deformation samples was inhomogeneous. The alloy was more sensitive to the deformation rate than to the temperature. The simulation results can provide a guideline for the optimization of the microstructure and hot deformation parameters of the Cu-9Ni-6Sn-0.3Mn-0.2Zn alloy.
10.3390-ma16041592	15	aging; strength; conductivity; electrical conductivity; electrical; mpa; treatment; strengthening; degrees; cu-; cold; precipitation; tensile strength; tensile; iacs	In order to study the effect of the rolling process and aging on the microstructure evolution and mechanical and tribological properties of the material, room-temperature rolling (RTR), cryogenic rolling (CR), and deep cryogenic treatment after rolling (RTR + DCT) experiments were carried out on a Cu-1.0Cr-0.1Zr alloy by a large plastic deformation process. Alloy plates were aged at 550 degrees C for 60 min. Different rolling processes and aging treatments have different effects on the microstructure and properties of alloy plates. The alloy plate is rolled and deformed, and the grains change from equiaxed to layered. Compared with RTR and RTR + DCT treatment, CR can promote the precipitation of the Cr phase and the degree of grain fragmentation is greater. After aging treatment, the Cu-Zr mesophase compounds in the microstructure increased, the alloys treated with CR and RTR + DCT appeared to be partially recrystallized, and the number of twins in the CR alloy plate was significantly more than that of RTR + DCT. The ultimate tensile strength of the alloy plate reached 553 MPa and the hardness reached 170 HV after cryogenic rolling with 90% deformation, which indicates that CR treatment can further improve the physical properties of the alloy plate. After aging at 550 degrees C for 60 min, the RTR 90% + DCT alloy plate has a tensile strength of 498 MPa and an elongation of 47.9%, which is three times that of the as-rolled alloy plate. From the research on the tribological properties of alloy plates, we learned that the main wear mechanisms in the wear forms of CR and RTR + DCT alloy plates are adhesive wear and abrasive wear. Adhesive wear is dominant in the early stage, while abrasive wear is the dominant mechanism in the later stage of wear. The friction coefficient of the CR 90% alloy plate in the TD direction is close to 0.55, and the wear rate is 2.9 x 10(-4) mm(3)/Nm, indicating that the CR treatment further improves the wear resistance of the alloy plates.
10.3390-ma16041740	2	corrosion; surface; film; electrochemical; films; spectroscopy; layer; current; solution; potential; resistance; composition; x-ray; ions; showed	Copper and its alloys are used widely in marine environments, and anisotropic corrosion influences the corrosion kinetics of copper. Corrosion of copper in an electrolyte containing Cl- is described as a dissolution-deposition process, which is a prolonged process. Therefore, it is laborious to clarify the corrosion anisotropy in different stages. In this paper, electrochemical impedance spectroscopy (EIS) following elapsed open circuit potential (OCP) test with 0 h (0H), 24 h (24H) and 10 days (10D) was adopted. To exclude interruptions such as grain boundary and neighbor effect, single crystal (SC) Cu(100) and Cu(111) were employed. After 10D OCP, cross-sectional slices were cut and picked up by a focused ion beam (FIB). The results showed that the deposited oxide was Cu2O and Cu(100)/Cu(111) experienced different corrosion behaviors. In general, Cu(100) showed more excellent corrosion resistance. Combined with equivalent electrical circuit (EEC) diagrams, the corrosion mechanism of Cu(100)/Cu(111) in different stages was proposed. In the initial stage, a smaller capacitive loop of Cu(111) suggested preferential adsorption of Cl- on air-formed oxide film on Cu(111). Deposited oxide and exposed bare metals also played an important role in corrosion resistance. Rectangle indentations and pyramidal structures formed on Cu(100)/Cu(111), respectively. Finally, a perfect interface on Cu(100) explained the tremendous capacitive loop and higher impedance (14,274 omega;cm(2)). Moreover, defects in the oxides on Cu(111) provided channels for the penetration of electrolyte, leading to a lower impedance (9423 omega-cm(2)) after 10D corrosion.
10.3390-ma16062485	-1		In consideration of the characteristics of supergravity to strengthen solidification structures, the effect of the supergravity field (SGF) on the grain refinement and mechanical properties of Cu-0.5Sn alloys was investigated in this paper. Firstly, it was experimentally verified that the addition of Sn could effectively refine the grain. Subsequently, the variations in grain size, tensile strength, and plasticity of the Cu-0.5Sn alloy were compared in normal and SGF conditions. The results revealed that the tensile strength and plasticity of the alloy increased with the increase in gravity coefficient. The ultimate tensile strength of the Cu-0.5Sn alloy in a normal gravity field was 145.2 MPa, while it was 160.2, 165.3, 167.9, and 182.0 MPa in an SGF with G = 100, 300, 500, and 1000, respectively, and there was almost no effect on conductivity. Finally, it was clarified that the mechanism of grain refinement by SGF was that the intense convection caused the fracture of the dendrites to become new nucleating particles. The increased viscosity under SGF hindered the diffusion of atoms in the melt and slowed down the movement of atoms toward the nucleus, leading to a decrease in grain size.
10.3390-ma16072738	-1		By optimizing the fabrication method, copper components featuring (typically contradicting) advantageous electric conductivity and favorable mechanical properties can be acquired. In this study, we subjected conventional electroconductive copper to a single revolution of high pressure torsion (HPT) at room temperature (RT), searched for the conditions which would yield comparable structure characteristics (grain size) when deformed at a cryogenic temperature, and finally compared the mechanical and electric behaviors to assess specific differences and correlate them with the (sub)structural development. 180 degrees revolution of cryo-HPT imparted structure refinement comparable to 360 degrees revolution of room temperature HPT, i.e., the average grain size at the periphery of both the specimens was similar to 7 mu m. The 360 degrees RT HPT specimen exhibited preferential (111)||SD (shear direction) texture fiber in all the examined regions, whereas the 180 degrees cryo-HPT specimen exhibited more or less randomly oriented grains of equiaxed shapes featuring substantial substructure development of a relatively homogeneous character and massive occurrence of (nano)twins. These structural features resulted in the increase in microhardness to the average value of 118.2 HV0.2 and the increase in the electric conductivity to 59.66 MS center dot m(-1) (compared to 105 HV0.2 and 59.14 MS center dot m(-1) acquired for the 360 degrees RT HPT specimen). The deformation under the cryogenic conditions also imparted higher homogeneity of microhardness distribution when compared to RT processing.
10.3390-ma16072746	-1		Here, 2% Cu + 2% Ni co-doped ZnO nanoparticles were synthesized using the hydrothermal method and were used as particle reinforcements of Cu-Ni nanocomposite coatings prepared by electroplating technology. The effects of the added (Cu, Ni) co-doped ZnO nanoparticles (2-8 g/L) on the phase structure, surface morphology, thickness, microhardness, corrosion resistance, and photocatalytic properties of the coatings were investigated. The nanocomposite coatings have obvious diffraction peaks on the crystal planes of (111), (200), and (220), showing a wurtzite structure. The surface of the nanocomposite coatings is cauliflower-like, and becomes smoother and denser with the increase in the addition of nanoparticles. The grain size, thickness, microhardness, corrosion resistance, and photocatalytic properties of the nanocomposite coating reach a peak value when the added (Cu, Ni) co-doped ZnO nanoparticles are 6 g/L. At this concentration, the mean crystallite size of the coating reaches a minimum of 15.31 nm, and the deposition efficiency of the coating is the highest. The (Cu, Ni) co-doped ZnO nanoparticle reinforcement makes the microhardness reach up to 658 HV. The addition of nanoparticles significantly improves the corrosion resistance and photocatalytic properties of nanocomposite coatings. The minimum corrosion current density is 2.36 x 10(-6) A/cm(2), the maximum corrosion potential is -0.301 V, and the highest decolorization rate of Rhodamine B is 28.73% after UV irradiation for 5 h .
10.3390-ma16072851	-1		Due to the unique functional properties of shape memory alloys (SMAs) and current scientific interest in Cu-containing biomaterials, a continuously cast Cu-Al-Ni alloy in the form of rods has been investigated as a potential candidate for biomedical application. Additionally, the fact that Cu- complexes have an antitumour effect served as a cornerstone to develop more efficient drugs based on trace element complexes. In line with that, our study aimed to analyse the basic properties of the Cu-Al-Ni alloy, along with its anticancer properties. The detailed chemical analysis of the Cu-Al-Ni alloy was performed using XRF and SEM/EDX analyses. Furthermore, a microstructural and structure investigation was carried out, combined with hardness measurements using the static Vickers method. Observations have shown that the Cu-Al-Ni microstructure is homogeneous, with the presence of typical martensitic laths. XRD analysis confirmed the presence of two phases, beta' (monoclinic) and gamma' (orthorhombic). The viability of osteosarcoma cells in contact with the Cu-Al-Ni alloy was evaluated using epifluorescence microscopy, while their morphology and attachment pattern were observed and analysed using a high-resolution SEM microscope. Biocompatibility testing showed that the Cu-Al-Ni alloy exerted a considerable antineoplastic effect.
10.3390-ma16072912	-1		The fabrication of high-performance copper alloys by selective laser melting (SLM) is challenging, and establishing relationships between the process parameters and microstructures is necessary. In this study, Cu-Cr-Nb-Ti alloy is manufactured by SLM, and the microstructures of the alloy are investigated by X-ray diffraction (XRD), scanning electron microscope (SEM), and electron backscatter diffraction (EBSD). The effects of processing parameters such as laser power and scanning speed on the relative density, defects, microstructures, mechanical properties, and electrical conductivity of the Cu-Cr-Nb-Ti alloy are studied. The optimal processing window for fabricating Cu-Cr-Nb-Ti alloy by SLM is determined. Face-centered cubic (FCC) Cu diffraction peaks shifting to small angles are observed, and there are no diffraction peaks related to the second phase. The grains of XY planes have a bimodal distribution with an average grain size of 24-55 mu m. Fine second phases with sizes of less than 50 nm are obtained. The microhardness, tensile strength, and elongation of the Cu-Cr-Nb-Ti alloy manufactured using the optimum processing parameters, laser power of 325 W and scanning speed of 800 mm/s, are 139 HV0.2, 416 MPa, and 27.8%, respectively, and the electrical conductivity is 15.6% IACS (International Annealed Copper Standard). This study provides a feasible scheme for preparing copper alloys with excellent performance and complex geometries.
10.3390-ma16093462	-1		The present study aimed to investigate the effect of cold deformation on the precipitation kinetics of a binary CuSc alloy containing 0.4 wt% scandium using the experimental analysis method of differential scanning calorimetry (DSC). Non-deformed and 75% cross-section-reduced cold-rolled supersaturated specimens were tested in non-isothermal DSC runs at up to five different heating rates. The DSC results showed that cold rolling significantly accelerated the precipitation process in the binary alloy, leading to a decrease in the initial and peak temperatures of the exothermic reactions. The activation energies calculated with the Kissinger method indicated that the precipitation activation energy decreased with increasing cold deformation. The findings of this study provide worthy implications to further optimize the processing of Cu-Sc alloys with improved mechanical properties.
10.3390-ma16103632	15	aging; strength; conductivity; electrical conductivity; electrical; mpa; treatment; strengthening; degrees; cu-; cold; precipitation; tensile strength; tensile; iacs	In this paper, Cu-6 wt%Ag alloy sheets were prepared using vacuum induction melting, heat treatment, and cold working rolling. We investigated the influence of the aging cooling rate on the microstructure and properties of Cu-6 wt%Ag alloy sheets. By reducing the cooling rate of the aging treatment, the mechanical properties of the cold-rolled Cu-6 wt%Ag alloy sheets were improved. The cold-rolled Cu-6 wt%Ag alloy sheet achieves a tensile strength of 1003 MPa and an electrical conductivity of 75% IACS (International Annealing Copper Standard), which is superior to the alloy fabricated with other methods. SEM characterization shows that the change in properties of the Cu-6 wt%Ag alloy sheets with the same deformation is due to a precipitation of the nano-Ag phase. The high-performance Cu-Ag sheets are expected to be used as Bitter disks for water-cooled high-field magnets.
10.3390-ma16114105	-1		A Cu-2.35Ni-0.69Si alloy with low La content was designed in order to study the role of La addition on microstructure evolution and comprehensive properties. The results indicate that the La element demonstrates a superior ability to combine with Ni and Si elements, via the formation of La-rich primary phases. Owing to existing La-rich primary phases, restricted grain growth was observed, due to the pinning effect during solid solution treatment. It was found that the activation energy of the Ni2Si phase precipitation decreased with the addition of La. Interestingly, the aggregation and distribution of the Ni2Si phase, around the La-rich phase, was observed during the aging process, owing to the attraction of Ni and Si atoms by the La-rich phase during the solid solution. Moreover, the mechanical and conductivity properties of aged alloy sheets suggest that the addition of the La element showed a slight reducing effect on the hardness and electrical conductivity. The decrease in hardness was due to the weakened dispersion and strengthening effect of the Ni2Si phase, while the decrease in electrical conductivity was due to the enhanced scattering of electrons by grain boundaries, caused by grain refinement. More notably, excellent thermal stabilities, including better softening resistance ability and microstructural stability, were detected for the low-La-alloyed Cu-Ni-Si sheet, owing to the delayed recrystallization and restricted grain growth caused by the La-rich phases.
10.3390-ma16124455	-1		The Portevin-Le Chatelier effect of Cu-2.0Be alloy was investigated using hot isothermal compression at varying strain rates (0.01-10 s(-1)) and temperature (903-1063 K). An Arrhenius-type constitutive equation was developed, and the average activation was determined. Both strain-rate-sensitive and temperature-sensitive serrations were identified. The stress-strain curve exhibited three types of serrations: type A at high strain rates, type B (mixed A + B) at medium strain rates, and type C at low strain rates. The serration mechanism is mainly affected by the interaction between the velocity of solute atom diffusion and movable dislocations. As the strain rate increases, the dislocations outpace the diffusion speed of the solute atoms, limiting their ability to effectively pin the dislocations, resulting in lower dislocation density and serration amplitude. Moreover, the dynamic phase transformation triggers the formation of nanoscale dispersive & beta; phases, which impede dislocation and cause a rapid increase in the effective stress required for unpinning, leading to the formation of mixed A + B serrations at 1 s(-1).
10.3390-ma16134780	-1		Designing a composite, possibly strengthened by a dispersion of (fine) oxides, is a favorable way to improve the mechanical characteristics of Cu while maintaining its advantageous electric conductivity. The aim of this study was to perform mechanical alloying of a Cu powder with a powder of Al2O3 oxide, seal the powder mixture into evacuated Cu tubular containers, i.e., cans, and apply gradual direct consolidation via rotary swaging at elevated temperatures, as well as at room temperature (final passes) to find the most convenient way to produce the designed Al2O3 particle-strengthened Cu composite. The composites swaged with the total swaging degree of 1.83 to consolidated rods with a diameter of 10 mm were subjected to measurements of electroconductivity, investigations of mechanical behavior via compression testing, and detailed microstructure observations. The results revealed that the applied swaging degree was sufficient to fully consolidate the canned powders, even at moderate and ambient temperatures. In other words, the final structures, featuring ultra-fine grains, did not exhibit voids or remnants of unconsolidated powder particles. The swaged composites featured favorable plasticity regardless of the selected processing route. The flow stress curves exhibited the establishment of steady states with increasing strain, regardless of the applied strain rate. The electroconductivity of the composite swaged at elevated temperatures, featuring homogeneous distribution of strengthening oxide particles and the average grain size of 1.8 & mu;m(2), reaching 80% IACS (International Annealed Copper Standard).
10.3390-ma16144925	-1		2 at% Cu + 2 at% Ni were co-doped in ZnO nanoparticles by a simple hydrothermal method, and then the modified nanoparticles were compounded into Cu-Ni alloy coatings using an electroplating technique. The effects of the current density (15-45 mA/cm(2)) on the phase structure, surface morphology, thickness, microhardness, corrosion resistance, and photocatalytic properties of the coatings were investigated. The results show that the Cu-Ni-Zn0.96Ni0.02Cu0.02O nanocomposite coatings had the highest compactness and the best overall performance at a current density of 35 mA/cm(2). At this point, the co-deposition rate reached its maximum, resulting in the deposition of more Zn0.96Ni0.02Cu0.02O nanoparticles in the coating. More nanoparticles were dispersed in the coating with a better particle strengthening effect, which resulted in a minimum crystallite size of 15.21 nm and a maximum microhardness of 558 HV. Moreover, the surface structure of the coatings became finer and denser. Therefore, the corrosion resistance was significantly improved with a corrosion current density of 2.21 x 10(-3) mA/cm(2), and the charge transfer resistance was up to 20.98 k & omega;& BULL;cm(2). The maximum decolorization rate of the rhodamine B solution was 24.08% under ultraviolet light irradiation for 5 h . The improvement in the comprehensive performance was mainly attributed to the greater concentration of Zn0.96Ni0.02Cu0.02O nanoparticles in the coating, which played the role of the particle-reinforced phase and reduced the microstructure defects.
10.3390-ma16145180	-1		To study the effects of Fe content and cold drawing strain on the microstructure and properties, Cu-Fe alloys were prepared via powder metallurgy and hot extrusion. Scanning electron microscopy was applied to observe the Fe phase, and the ultimate tensile strength was investigated using a universal material testing machine. Alloying with an Fe content below 10 wt% formed a spherically dispersed Fe phase via the conventional nucleation and growth mechanism, whereas a higher Fe content formed a water-droplet-like Fe phase via the spinodal decomposition mechanism in the as-extruded Cu-Fe alloy. Further cold drawing induced the fiber structure of the Fe phase (fiber strengthening), which could not be destroyed by subsequent annealing. As the Fe content increased, the strength increased but the electrical conductivity decreased; as the cold drawing strain increased, both the strength and the electrical conductivity roughly increased, but the elongation roughly decreased. After thermal-mechanical processing, the electrical conductivity and strength of the Cu-40Fe alloy could reach 51% IACS and 1.14 GPa, respectively. This study can provide insight into the design of high-performance Cu-Fe alloys by tailoring the size and morphology of the Fe phase.
10.3390-ma16165519	-1		In this paper, we investigated the effect of adding rhenium to Cu-Ni-Si alloys on the mechanical properties and electrical conductivity of these alloys. The scientific objective was to analyze the effect of Re addition on the microstructure of heat- and cold-treated CuNi2Si1 alloys. Transmission electron microscopy (TEM, STEM) and scanning electron microscopy (EDS, WDS) were used to examine the microstructure. Orientation mapping was also performed using a scanning electron microscope (SEM) equipped with a backscattered electron diffraction (EBSD) system. In addition, hardness at low load and conductivity were tested. The obtained results showed that modifying the chemical composition of Re (0.6 wt%) inhibits the recrystallization process in the CuNi2Si1 alloy, which was cold deformed and then subjected to recrystallization annealing.
10.3390-ma16175782	4	transformation; martensite; martensitic; phase; shape; beta; memory; shape memory; temperature; temperatures; martensitic transformation; gamma; transformation temperatures; effect; thermal	The influence of manganese content on the formation of martensite structure and the final properties of a quaternary Cu-Al-Mn-Ag shape memory alloy (SMA) was investigated. Two alloys with designed compositions, Cu- 9%wt. Al- 16%wt. Mn- 2%wt. Ag and Cu- 9%wt. Al- 7%wt. Mn- 2%wt. Ag, were prepared in an electric arc furnace by melting of high-purity metals. As-cast and quenched microstructures were determined by optical microscopy and scanning electron microscopy equipped with EDS. Phases were confirmed by high-energy synchrotron radiation and electron backscatter diffractions. Austenite and martensite transformations were followed by differential scanning calorimetry and hardness was determined using the Vickers hardness test. It was found that the addition of silver contributes to the formation of the martensite structure in the Cu-Al-Mn-SMA. In the alloy with 7%wt. of manganese, stable martensite is formed even in the as-cast state without additional heat treatment, while the alloy with 16%wt. of manganese martensite transforms only after thermal stabilization and quenching. Two types of martensite, & beta;1 & PRIME; and & gamma;1 & PRIME;, are confirmed in the Cu-9Al-7Mn-2Ag specimen. The as-cast SMA with 7%wt. Mn showed significantly lower martensite transformation temperatures, Ms and Mf, in relation to the quenched alloy. With increasing manganese content, the Ms and Mf temperatures are shifted to higher values and the microhardness is lower.
10.3390-ma16196508	15	aging; strength; conductivity; electrical conductivity; electrical; mpa; treatment; strengthening; degrees; cu-; cold; precipitation; tensile strength; tensile; iacs	In this paper, a Cu-Ni-Cr alloy was prepared by adding a Ni-Cr intermediate alloy to copper. The effects of the cold rolling reduction rate on the microstructure and properties of the Cu-1.16Ni-0.36Cr alloy after thermo-mechanical treatment were studied. The results show that the tensile strength of the alloy increased while the electrical conductivity slightly decreased with an increase of the cold rolling reduction rate. At a rolling strain of 3.2, the tensile strength was 512.0 MPa and the conductivity was 45.5% IACS. At a rolling strain of 4.3, the strength further increased to 536.1 MPa and the conductivity decreased to 41.9% IACS. The grain size and dislocation density decreased with an increase of the reduction rate in the thermo-mechanical treatment. However, when the rolling strain reached 4.3, the recrystallization degree of the alloy increased due to an accumulation of the dislocation density and deformation energy, resulting in a slight increase in the grain size and a decrease in the dislocation density. The texture strength of the brass increased due to the induced shear band, with an increase of the cold rolling reduction rate. The reduction rate promoted a uniform distribution of nano-scale Cr precipitates and further enhanced the strength via precipitation strengthening.
10.3390-ma16206658	-1		To reduce the use of the toxic Pb element in the Cu-Sn alloy with high friction performance, Cu-xBi-10Sn alloys with different Bi contents were prepared by gravity casting, and the effect of Bi content on the microstructure, mechanical properties and wear property of Cu-Sn alloys were studied. The results showed that the Bi element was distributed in bands or long strips on the dendritic arms and did not form compounds with other elements. With the increase in Bi content, the hardness and tensile strength of Cu-xBi-10Sn alloys present a trend of increasing first and then decreasing. When the Bi content was 7 wt%, the maximum hardness value was obtained, and the ultimate tensile strength was close to that of Cu-10Pb-10Sn alloy. Compared with Cu-10Pb-10Sn alloy, Cu-7Bi-10Sn alloy also possessed better friction reduction and wear resistance under the oil lubrication condition.
10.3390-ma16237455	-1		Copper matrix composites with zirconium diboride (ZrB2) were synthesised by ball milling and consolidated by Spark Plasma Sintering (SPS). Characterisations of the ball-milled composite powders were performed by scanning electron microscopy (SEM), X-ray diffraction, and measurement of the particle size distribution. The effect of the sintering temperature (1123 K, 1173 K, and 1223 K) and pressure (20 MPa and 35 MPa) on the density, porosity, and Young's modulus was investigated. The relationship between the change of Orb content and physical, mechanical, and electrical properties was studied. Experimental data showed that the properties of Cu-Orb composites depended significantly on the SPS sintering conditions. The optimal sintering temperature was 1223 K with a pressure of 35 MPa. Composites exhibited a high degree of consolidation. For these materials, the apparent density was in the range of 93-97%. The results showed that the higher content of Orb in the copper matrix was responsible for the improvement in Young's modulus and hardness with the reduction of the conductivity of sintered composites. The results showed that Young's modulus and the hardness of the Cu 20% Orb composites were the highest, and were 165 GPa and 174 HV0.3, respectively. These composites had the lowest relative electrical conductivity of 17%.
10.3390-ma16237481	-1		In the present study, the properties of Cu(Ag) alloy films were studied to evaluate their potential use as an alternate material for interconnection in hybrid bonding. Thin alloy films of Cu(Ag) were deposited by pulsed electrochemical deposition (PED) using a sulfuric acid-based bath, rotating disk electrode, and hot entry. Secondary ion mass spectrometry (SIMS) was used to measure the silver content of the films, with us finding that it decreases with increasing duty cycle. Thereafter, bright field scanning transmission electron microscope (STEM) imaging in combination with energy-dispersive x-ray spectroscopy (EDS) was used to visualize the thin film microstructure and to confirm the uniform distribution of silver throughout the film, with no bands being seen despite the pulsed nature of the deposition. Film resistance was measured by a four-point probe to quantify the impact of Ag content on resistivity, with us finding the expected linear relationship with the Ag content in the film. Furthermore, the coefficient of thermal expansion (CTE) of the films was measured using X-ray diffraction, and modulus and hardness were measured via nanoindentation, revealing linear dependences on the Ag content as well. Notably, the addition of 1.25 atom% Ag resulted in a significant increase in the CTE from 17.9 to 19.3 ppm/K, Young's modulus from 111 to 161 GPa, and film hardness from 1.70 to 3.99 GPa. These simple relationships offer a range of properties tunable via the duty cycle of the pulsed plating, making Cu(Ag) a promising candidate for engineering wafer-to-wafer metal interconnections.
10.3390-ma17010050	5	materials; thermal; heat; properties; material; welding; sintering; fusion; strength; laser; heat sink; thermal conductivity; mechanical; sink; manufacturing	In the case of copper and its alloys, Wire Arc Additive Manufacturing (WAAM) 3D printing technology is mainly used to produce elements for the maritime industry and research has focused on the use of Cu-Al alloys. There is little information devoted to the use of Cu-Ni alloys in this technology, which are also widely used in the maritime industry. In this work, tests were carried out on the microstructure, mechanical properties, and corrosion properties in a 1M NaCl solution of Cu-Ni 90/10 alloy 3D walls printed using the WAAM method. The obtained objects are characterized by a microstructure with elongated column grains and particles of the Ni-Ti phase, hardness in the range of 138-160 HV10, ultimate tensile strength of 495-520 MPa, yield strength of 342-358 MPa, elongation of 16.6-17.9%, and a low average corrosion rate of 7.4 x 10-5 mm/year. The work shows that it is possible to obtain higher mechanical properties of Cu-Ni 90/10 alloy 3D objects produced using the WAAM method compared to cast materials, which opens up the possibility of using this alloy to produce objects with more complex shapes and for use in corrosive working conditions.
10.3390-ma17030719	14	strength; properties; conductivity; electrical; mechanical; cu-; grain; mpa; electrical conductivity; aging; precipitation; phase; mechanical properties; tensile; phases	To explore the crystalline arrangement of the alloy and the processes involving iron (Fe) precipitation, we employed molecular dynamics simulation with a cooling rate of 2 x 1010 for Cu100-XFeX (where X represents 1%, 3%, 5%, and 10%) alloy. The results reveal that when the Fe content was 1%, Fe atoms consistently remained uniformly distributed as the temperature of the alloy decreased. Further, there was no Fe atom aggregation phenomenon. The crystal structure was identified as an FCC-based Cu crystal, and Fe atoms existed in the matrix in solid solution form. When the Fe content was 3%, Fe atoms tended to aggregate with the decreasing temperature of the alloy. Moreover, the proportion of BCC crystal structure exhibited no obvious changes, and the crystal structure remained FCC-based Cu crystal. When the Fe content was between 5% and 10%, the Fe atoms exhibited obvious aggregation with the decreasing temperature of the alloy. At the same time, the aggregation phenomenon was found to be more significant with a higher Fe content. Fe atom precipitation behaviour can be delineated into three distinct stages. The initial stage involves the gradual accumulation of Fe clusters, characterised by a progressively stable cluster size. This phenomenon arises due to the interplay between atomic attraction and the thermal motion of Fe-Fe atoms. In the second stage, small Fe clusters undergo amalgamation and growth . This growth is facilitated by non-diffusive local structural rearrangements of atoms within the alloy. The third and final stage represents a phase of equilibrium where both the size and quantity of Fe clusters remain essentially constant following the crystallisation of the alloy.
10.3390-ma17040876	-1		The 70/30 copper-nickel alloy is used mainly in critical parts with more demanding conditions in marine settings. There is a need for innovative methods that offer fast production and cost-effectiveness in order to supplement current copper-nickel alloy manufacturing processes. In this study, we employ wire arc additive manufacturing (WAAM) to fabricate the 70/30 copper-nickel alloy. The as-built microstructure is characterized by columnar grains with prominent dendrites and chemical segregation in the inter-dendritic area. The aspect ratio of the columnar grain increases with increasing travel speed (TS) at the same wire feed speed (WFS). This is in contrast with the equiaxed grain structure, with a more random orientation, of the conventional sample. The sample built with a WFS of 8 m/min, TS of 1000 mm/min, and a track distance of 3.85 mm exhibits superior corrosion properties in the 3.5 wt% NaCl solution when compared with the conventional sample, as evidenced by a higher film resistance and breakdown potential, along with a lower passive current density of the WAAM sample. The corrosion morphology reveals the critical roles played by the nickel element that is unevenly distributed between the dendrite core and inter-dendritic area.
10.3390-ma17092015	8	hot; deformation; strain; strain rate; dynamic; hot deformation; recrystallization; dynamic recrystallization; flow; rate; flow stress; compression; constitutive; degrees; stress	Thermal deformation behavior of Cu-Cr-Sn alloy ingots under deformation temperatures ranging from 600 degrees C to 950 degrees C and strain rates from 0.01 s-1 to 10 s-1 was investigated in detail. The thermal deformation constitutive equation and thermal processing map of the alloy were established, respectively. The activation energy Q was determined as 430.61 KJ/mol. The optimal deformation system corresponding to the hot working diagram was a deformation temperature of 900 degrees C and strain rate of 0.1 s-1. Under these deformation conditions, twin dynamic recrystallization (TDRX), continuous dynamic recrystallization (CDRX), and discontinuous dynamic recrystallization (DDRX) occurred simultaneously, with the twinning process causing the stress-strain curve to exhibit a wavy change. The thermal deformation microstructure of the alloy is co-regulated by different recrystallization mechanisms, with DDRX occurring mainly at low deformation temperatures, and both CDRX and DDRX occurring at high deformation temperatures.
10.3390-ma17112504	-1		The composition of grain boundaries (GBs) determines their mechanical behavior, which in turn affects the mechanical properties of nanocrystalline materials. Inspired by GB segregation and the concept of high-entropy alloys (HEAs), we investigated, respectively, the mechanical responses of nanocrystalline Cu samples with and without multi-element GBs, as well as the grain size effects, aiming to explore the effects of GB composition decoration on mechanical properties. Our results show that introducing multi-element segregation GBs can significantly improve the mechanical properties of nanocrystalline Cu by effectively inhibiting GB migration and sliding. Additionally, we proposed an improved a theoretical model that can reasonably describe the strengths of the materials with multi-element or single-element segregation GBs. Notably, the introduction of multi-element segregation GBs inhibits both migration and sliding behavior, with migration being more effectively suppressed than sliding. These results present a novel approach for designing high-performance nanometallic materials and offer valuable insights into the role of GB composition decoration in enhancing mechanical properties.
10.3390-ma17112696	-1		The microstructure and texture evolution of Cu-Ni-P alloy after cold rolling and annealing at 500 degrees C was studied by electron backscattering diffraction (EBSD). The equiaxed grain is elongated and the dislocation density increases gradually after cold rolling. The grain boundaries become blurred and the structure becomes banded when the reduction in cold rolling reaches 95%. A typical rolling texture is formed with the increase in deformation amount in cold rolling. The deformation structure gradually disappeared and recrystallized new grains were formed after annealing at 500 degrees C. The recrystallization nucleation mechanism of Cu-Ni-P alloy at 60% reduction is mainly a bow nucleation mechanism. A shear band begins to form after annealing at 80% reduction. The shear band becomes the preferred nucleation location with the increase in reduction. Most adjacent recrystallized grains growing in the shear band have a twin relationship.
10.3390-ma17122943	-1		This study investigated the impact of low-temperature heat treatments on the mechanical and thermophysical properties of Cu-10Sn alloys fabricated by a laser powder bed fusion (LPBF) additive manufacturing (AM) process. The microstructure, phase structure, and mechanical and thermal properties of the LPBF Cu-10Sn samples were comparatively investigated under both the as-fabricated (AF) condition and after low-temperature heat treatments at 140, 180, 220, 260, and 300 degrees C. The results showed that the low-temperature heat treatments did not significantly affect the phase and grain structures of the Cu-10Sn alloys. Both pre- and post-treatment samples displayed consistent grain sizes, with no obvious X-ray diffraction angle shift for the alpha phase, indicating that atom diffusion of the Sn element is beyond the detection resolution of X-ray diffractometers (XRD). However, the 180 degrees C heat-treated sample exhibited the highest hardness, while the AF samples had the lowest hardness, which was most likely due to the generation of precipitates according to thermodynamics modeling. Heat-treated samples also displayed higher thermal diffusivity values than their AF counterpart. The AF sample had the longest lifetime of similar to 0.19 nanoseconds (ns) in the positron annihilation lifetime spectroscopy (PALS) test, indicating the presence of the most atomic-level defects.
10.3390-ma17123020	-1		The continuous industrial development that occurs worldwide generates the need to develop new materials with increasingly higher functional properties. This need also applies to the basic material for electricity purposes, which is copper. In this article, we carry out studies on the influence of various alloying elements such as Mg, In, Si, Nb, Hf, Sb, Ni, Al, Fe, Zr, Cr, Zn, P, Ag, Sc, Pb, Sn, Co, Ti, Mn, Te and Bi on the electrical and mechanical properties of ETP-grade copper. The research involves producing copper alloys using the gravity die casting method with alloy additions of 0.1 wt%, 0.3 wt% and 0.5 wt%. All resulting materials are cold-worked to produce wires, which are subsequently homogenized and annealed. The materials produced in this manner undergo testing to determine their specific electrical conductivity, tensile strength, yield strength, elongation and Vickers hardness (HV10 scale).
10.3390-ma17184485	-1		With the development of modern technology, the construction industry, and navigation technology, the metal Cu alloy has become an important metal material in mainstream industrial applications. As an indispensable basic metal material in the field of science and technology, its problem with corrosion is still a long-term problem that scientists have been working to solve. In this paper, air spraying technology is used to prepare an Al2O3-PDMS composite coating. By adjusting the content of Al2O3, the surface of the Cu alloy can reach different wetting states. The results show that the corrosion potential of the as-prepared superhydrophobic Al2O3-PDMS coating increases by 70 mV compared with the substrate, the corrosion current density decreases by one order of magnitude, and the impedance modulus increases from 2000 to 12,000 Omega & sdot;cm(2), indicating a significantly enhanced corrosion resistance. It also possesses excellent anti-pollution and anti-icing behaviors, thereby allowing them to work in harsh industrial conditions.
10.3390-ma17194847	16	wear; composite; composites; powders; milling; particles; powder; wt; sliding; friction; hardness; matrix; mechanical; surface; properties	The aim of this work is to obtain Cu-13.5Al-4Ni alloy for use as shape memory alloy by Spark Plasma Sintering (SPS) of mechanically alloyed powder. The study investigates the structural and microstructural changes in terms of crystal parameters, crystallite sizes, and phases evolution during mechanical alloying and spark plasma sintering of Cu-13.5Al-4Ni powders. We obtained alloyed powders with a structure composed of alpha(Cu), AlNi intermetallic compound and small amounts of elemental Al through the mechanical alloying technique. After spark plasma sintering at 900 degrees C, the microstructure consists of an AlNi compound distributed at the edge of alpha(Cu) grains. The crystallite sizes of both, alpha(Cu) and AlNi are in nanoscale order after 16 h of milling (9 and 6.5 nm respectively). After sintering at 900 degrees C (in Ar atmosphere, without holding time), the crystallite sizes increase to 46 nm for alpha(Cu) and to 40 nm for AlNi compound. Also, the Cu-13.5Al-4Ni compacts achieve a final density after sintering at 900 degrees C of around 80% from the theoretical density.
10.3390-ma17205112	-1		Cu alloys have been widely used in the manufacture of liners because of their high density, good plasticity, and excellent thermal conductivity. In order to achieve excellent jet stability and penetration performance, it is necessary to further improve the mechanical properties of Cu-based liners. Nevertheless, the simultaneous enhancement of strength and ductility of the Cu alloys remains a huge challenge due to the strength-ductility trade-off phenomenon of metals/alloys. In this study, the microstructure evolution of rare earth Nd-modified Cu alloy and its effect on mechanical properties were investigated using OM, SEM, EBSD, and TEM techniques. The results show that the ultimate tensile strength (218 MPa) and elongation (50.7%) of sample 1 without Nd are the lowest. With increasing Nd content; the tensile strength and elongation of the samples increase; and the mechanical properties of sample 4 are the best, with a tensile strength of 278.6 MPa and elongation of 65.2%. In addition, with the increase in Nd content, not only is the grain size of the Cu-Nd alloy refined, but also the strength and plasticity are improved so that the strength-ductility trade-off phenomenon is improved. The strength improvement is mainly attributed to grain refinement strengthening, dispersion strengthening, and strain hardening. The increase in ductility is mainly related to the improvement of the microstructure heterogeneity by the Nd element.
10.3390-ma17225658	14	strength; properties; conductivity; electrical; mechanical; cu-; grain; mpa; electrical conductivity; aging; precipitation; phase; mechanical properties; tensile; phases	Discontinuous precipitation-strengthened Cu-Ni-Si alloys are highly regarded for their combination of high strength and excellent electrical conductivity. However, the slow process of discontinuous precipitation, typically requiring up to 24 h for complete formation, significantly increases the alloy's production costs and limits potential improvements in its properties. This study addresses this issue by applying pre-deformation to Cu-6Ni-1.42Si alloys, which accelerated the discontinuous precipitation (DP) of Ni2Si by approximately 48 times, resulting in the formation of fast DP and full DP alloys. The fast DP alloy exhibited a smaller DP size and inter-distance than the full DP alloy, achieving a tensile strength of 1070 MPa and a conductivity of 38.5% IACS. In contrast, the full DP alloy had a slightly lower tensile strength (approximately 930 MPa) but a higher conductivity of 46% IACS. Both alloys outperform traditional Cu-Ni-Si alloys in strength while maintaining comparable conductivity. The accelerated DP technique improves mechanical properties without significantly sacrificing conductivity, offering a new approach for high-performance conductive materials.
10.3390-ma17236017	14	strength; properties; conductivity; electrical; mechanical; cu-; grain; mpa; electrical conductivity; aging; precipitation; phase; mechanical properties; tensile; phases	Copper, though highly conductive, requires improved wear resistance and thermal dissipation in applications that involve continuous movement and current-induced vibrations, such as power breakers. Conventional solutions, such as copper-tungsten alloys or lubricant use, face limitations in durability, friction, or environmental impact. This study explores the development of copper-graphene (Cu-GNPs) composite coatings using pulsed electrodeposition to enhance the tribological, thermal, and mechanical properties of circuit breaker components by adopting an industrially scalable technique. The influence of deposition bath temperature, duty cycle, and frequency on coating morphology, hardness, wear resistance, and heat dissipation was systematically evaluated using a 23 full factorial design and an Analysis of Variance (ANOVA). The results revealed that optimized pulsed electrodeposition significantly improved coating performance: hardness increased by 76%, wear volume decreased by more than 99%, and friction coefficient stabilized at 0.2, reflecting effective graphene integration. The addition of graphene further improved thermal diffusivity by 19.5%, supporting superior heat dissipation. These findings suggest that pulsed copper-graphene composite coatings offer a promising alternative to traditional copper alloys, enhancing the lifespan and reliability of electronic components through improved wear resistance, lower friction, and superior heat transfer.
10.3390-ma17246165	3	sma; shape; shape memory; memory; smas; superelastic; bars; damping; cu-al-mn; mechanical; bending; applications; numerical; sma bars; material	Shape memory alloys (SMAs) are functional materials with a wide range of applications, from the aerospace sector to the biomedical field. Nowadays, there is a worldwide interest in developing SMAs through powder metallurgy like additive manufacturing (AM), which allows innovative building processes. However, producing SMAs using AM techniques is particularly challenging because of the microstructure required to obtain optimal functional properties. This aspect is critical in the case of Cu-Al-based SMAs, due to their high elastic anisotropy, making them brittle in polycrystalline form. In this work, we approached the processing of a Cu-Al-Ni SMA following a specific powder metallurgy route: gas atomization of a pre-alloyed melt; compaction of the atomized powders through hot isostatic pressing; and a final hot rolling plus thermal treatments. Then, the microstructure of the material was characterized by electron microscopy showing a specific [001] texture in the rolling direction that improved the functional behavior. The successive processing steps produce an increase of about 40 degrees C in the martensitic transformation temperatures, which can be well controlled and reproduced through the developed methodology. The thermomechanical functional properties of superelasticity and shape memory were evaluated on the final SMA. Outstanding, fully recoverable superelastic behavior of 4.5% in tension, as well as a +/- 5% full shape memory recovery in bending, were reported for many cycles. These experiments demonstrate the enhanced mechanical and functional properties obtained in polycrystalline Cu-Al-Ni SMAs by powder metallurgy. The present results pave the road for producing this kind of SMA with the new AM technologies, which always produce polycrystalline components and can improve their processes taking the powder metallurgy SMA, here produced, as reference material.
10.3390-ma17246270	14	strength; properties; conductivity; electrical; mechanical; cu-; grain; mpa; electrical conductivity; aging; precipitation; phase; mechanical properties; tensile; phases	Pure copper (Cu) is widely used across numerous industries owing to its exceptional thermal and electrical conductivity. Additive manufacturing has facilitated the rapid and cost-effective prototyping of Cu components. Laser powder bed fusion (LPBF) has demonstrated the capability to produce intricate Cu components. However, LPBF-fabricated components exhibit anisotropic features, which stem from their inherent thermal gradients, resulting in properties that depend on the grain orientation. In the present study, pure Cu samples were fabricated via micro-laser powder bed fusion (mu LPBF), resulting in improved mechanical properties, specifically, enhanced strength and ductility. The as-printed pure Cu sample exhibited thermal stability owing to its high-density grain boundaries and dislocations, enabling it to maintain relatively high levels of strength and ductility even when exposed to an elevated temperature of 300 degrees C. Furthermore, the heat treatment resulted in the disappearance of the initial microstructural characteristics, such as molten pool boundaries. As the heat-treatment temperature increased, the anisotropic yield strength decreased. Overall, the anisotropy of the properties of pure Cu components fabricated via mu LPBF can be mitigated through heat-treatment-induced microstructural adjustments.
10.3390-ma18010125	14	strength; properties; conductivity; electrical; mechanical; cu-; grain; mpa; electrical conductivity; aging; precipitation; phase; mechanical properties; tensile; phases	Copper matrix composites (Cu-MCs) have garnered significant attention due to their exceptional electrical, wear-resistant, and mechanical properties. Among them, Al2O3/Cu composites, reinforced with Al2O3, are a focal point in the field of high-strength, high-conductivity copper alloys, owing to their high strength, excellent electrical conductivity, and superior resistance to high-temperature softening. Cold deformation is an effective method for enhancing the mechanical properties of Al2O3/Cu composites. However, during cold deformation of large-cross-sectional Al2O3/Cu composites, the inhomogeneity in microstructure and properties induced by varying stress states cannot be overlooked. In this study, cold deformation of 1.12 wt% Al2O3/Cu large-cross-sectional composites was performed using a rolling process, coupled with finite element numerical simulations, to investigate the distribution characteristics of microstructure and properties during the rolling process. The results indicate that under cold deformation, the hardness of the material increases linearly from the surface layer to the core, while the change in electrical conductivity is minimal. The increase in hardness is closely related to variations in dislocation density and grain size, with dislocation density being the dominant strengthening mechanism. Quantitative analysis reveals that strain inhomogeneity during cold deformation is the primary cause of microstructural differences, leading to variations in mechanical properties at different positions. This study provides a theoretical basis for understanding the inhomogeneity of cold deformation in large-sized Al2O3/Cu composites and for controlling their microstructure-property relationships.
10.3390-ma18030560	14	strength; properties; conductivity; electrical; mechanical; cu-; grain; mpa; electrical conductivity; aging; precipitation; phase; mechanical properties; tensile; phases	The copper-based steel backing material is prepared using a combination of mechanical alloying and secondary sintering methods. The effect of Y2O3 content on the microstructure, hardness, and tribological properties of the copper-based self-lubricating layer is investigated. The results demonstrate that the addition of Y2O3 enhances the strength of the copper-based self-lubricating layer. Graphite and Y2O3 act synergistically to form a three-dimensional supporting framework, thereby boosting the overall strength of the copper-based composite material and increasing its Brinell hardness by 27%. Additionally, the incorporation of Y2O3 effectively improves the tribological properties of the composite material, significantly reducing wear during the friction process and decreasing the wear rate by 77%. Under the experimental conditions, the optimal Y2O3 content is determined to be 1 wt%.
10.3390-ma18030581	14	strength; properties; conductivity; electrical; mechanical; cu-; grain; mpa; electrical conductivity; aging; precipitation; phase; mechanical properties; tensile; phases	The field of artificial intelligence and integrated circuits is experiencing rapid development, particularly in the area of highly integrated and miniaturized components, in which Cu-Ag alloys, as a typical lead frame material, play a crucial role. However, current research is primarily focused on low Ag content alloys, and there are few studies on the regulation of the microstructure and mechanical properties of high Ag content Cu-Ag alloys. This limitation hindered the development and utilization of the high Ag content Cu-Ag alloys. In this study, the microstructure and mechanical properties of Cu-28Ag (wt. %) alloy after room temperature and cryogenic rolling were investigated. It was demonstrated that the cryogenic rolling yielded better surface quality, an enhanced dendrite refinement effect, and a more distinct layer structure compared to room temperature rolling. The conductivity of the alloy decreased after cryogenic rolling due to increased electron scattering within the Cu matrix. The tensile strength improved, but the elongation decreased. Specifically, at a deformation amount of 95%, the alloy exhibited an ultimate tensile strength, yield strength, and elongation of 640 MPa, 631 MPa, and 1.9%, respectively. This strengthening was mainly attributed to the refinement of grains, the presence of dislocations, and precipitation. Furthermore, the samples subjected to liquid nitrogen rolling at a deformation amount of 95% exhibited improved homogeneous deformation capacity, which was attributed to grain size refinement, uniform distribution of high-density dislocations, deformation structure, and heterogeneity-induced deformation enhancement.
10.3390-ma18040839	-1		This study primarily investigated the microstructural and mechanical properties of Cu-Ni-Be alloys subjected to thermomechanical treatments at 30% and 75% deformation levels. Precipitates in Cu-Ni-Be alloys are dominated by Ni-Be phases. The misfit between the Ni-Be phase/Cu interface is 0.12%. Experimental observations have revealed the existence of three classical orientation relationships between precipitates and the matrix: (110)p//(100)alpha; [110]p//[001]alpha, (110)p//(010)alpha; [110]p//[001]alpha, and (110)p//(100)alpha; [001]p//[001]alpha (p: precipitates, alpha: alpha-Cu supersaturated solid solution). Additionally, a fourth orientation relationship, (110)p//(1-1-1)alpha; [110]gp//[1-1-1]alpha (gp: Guinier-Preston), induced by deformation, has also been identified. The width of the second phase was found to be two to three atomic layers. Under 75% deformation, a substantial amount of the gamma ' phase emerged at grain boundaries. Notably, at neither 30% nor 75% deformation levels were prominent cellular structures observed.
10.3390-ma18051103	14	strength; properties; conductivity; electrical; mechanical; cu-; grain; mpa; electrical conductivity; aging; precipitation; phase; mechanical properties; tensile; phases	Advancements in electrical components have intensified the challenges for copper alloy wear resistance and high-temperature performance in electrical applications. The surface coating preparation of Cu alloys is crucial for enhancing their lifespan and promoting sustainable resource development. This study explored the microstructure and properties of Cu-Cr-X coatings (X = Mo/W, Al2O3/TiO2) on Cu alloy substrates via laser-cladding to improve wear resistance and hardness, vital for electrical component reliability and switching capacity. The process involved adjusting the power and reinforcing the phase particle size. The results showed hardness > 110 HV for all coatings (vs. 67.4 HV for the substrate). Cu-Cr-W achieved the highest hardness at 179 HV due to W dispersion and WCr precipitate reinforcement. It also maintained a stable CoF and the lowest wear rate (1.87 mg/km), with a fivefold wear resistance compared to the substrate alone. Cu-Cr-W excelled in lifespan extension and material loss reduction due to superior hardness, wear resistance, and conductivity.
10.3390-ma18061325	14	strength; properties; conductivity; electrical; mechanical; cu-; grain; mpa; electrical conductivity; aging; precipitation; phase; mechanical properties; tensile; phases	This study systematically investigates how Fe-Ti atomic ratios (1:1, 1:2, and 2:1) influence the microstructure, mechanical properties, and softening resistance of Cu-Fe-Mg-Ti alloys under fixed total Fe + Ti content. Through hardness testing, electrical conductivity measurements, and multiscale characterization (optical microscopy, scanning/transmission electron microscopy, and X-ray diffraction), we reveal a previously unreported phenomenon: Ti-dominated ratios (1:2) enable superior strength-conductivity synergy. After 70% cold rolling and 550 degrees C aging, the alloy with a 2:1 Fe/Ti ratio exhibits peak hardness (166.5 HV) and conductivity (64.1% IACS), outperforming both 1:1 (173.9 HV, 51.3% IACS) and 1:2 (189.5 HV, 44.2% IACS) counterparts. Critical microstructure analysis confirms that increased Ti content promotes high-density Fe2Ti nanoprecipitation (5-15 nm) with coherent interfaces, enhancing strength while mitigating electron scattering. This work establishes atomic ratio optimization as a novel strategy to break the traditional strength-conductivity trade-off in copper alloys, providing a 21% hardness improvement over conventional Fe-Ti systems without sacrificing essential electrical performance.
10.3390-ma18071401	-1		In this study, the results of transmission electron microscopy (TEM) examinations of neutron-irradiated (2.5 dpa at 150 degrees C, 350 degrees C, and 450 degrees C) CuCrZrV and ODS(Y2O3)-Cu alloys are presented. These materials were developed for application as heat sink materials in fusion technology. This study includes TEM imaging and quantitative analysis of neutron radiation-induced defects such as dislocation loops and voids as well as the determination of the conditions for their formation. It was found that dislocation loops of a0 1/2 < 110 > type form in both alloys at all irradiation temperatures. The formation of voids in CuCrZrV alloy is effectively suppressed. The neutron irradiation causes a redistribution of Cr, Zr, and V in the CuCrZrV alloy. A particular focus was on the investigation of the distribution of the transmutation products Ni and Zn. Ni tends to segregate at the Cr-rich clusters and forms a shell around them, while Zn is evenly distributed.
10.3390-ma18071606	14	strength; properties; conductivity; electrical; mechanical; cu-; grain; mpa; electrical conductivity; aging; precipitation; phase; mechanical properties; tensile; phases	This article presented an investigation into the microstructure evolution of a hot-extruded Cu-0.23Al(2)O(3) alloy during thermomechanical treatment. The results demonstrated that cold rolling deformation introduced high-density dislocations into the matrix, resulting in a significant enhancement in the strength of the Cu-0.23Al(2)O(3) alloy. Subsequent annealing at 500 for 1 h led to a reduction in dislocation density in the sample. Consequently, the strength of the sample decreased very slightly, while the elongation increased from 14% to 39%. There was little growth of the nano-scale Al2O3 particles due to their excellent thermal stability, with the average size remaining approximately 10 nm after annealing. The comprehensive properties of the Cu-0.23Al(2)O(3) alloy were improved synchronously by thermomechanical treatment, with a tensile strength of 301 MPa and an electrical conductivity of 98.5%IACS. The calculation results of the strengthening mechanism indicated that refinement strengthening, work hardening and Orowan strengthening mainly contributed to the high strength of the Cu-0.23Al(2)O(3) alloy.
10.3390-ma18081793	-1		The co-addition of chromium (Cr) and tin (Sn) is known to enhance the wettability between copper (Cu) and graphite (Cgr), but the effect of Sn content remains poorly understood. This study aims to systematically investigate the influence of Sn content a (a = 0, 10, 20, 30, 40, 50, 80, 99 at. %) on the wettability, interfacial structure, surface/interface energy (sigma lv/sigma sl), and adhesion behavior of the Cu-aSn-1Cr/Cgr system at 1100 degrees C. The experimental results show that as the Sn content increases, the equilibrium contact angle (theta e) of the metal droplet shows a non-monotonic trend; the thickness of the reaction product layer (RPL, consisting of Cr carbides (CrmCn)) gradually increases, accompanied by a decrease in the calculated adhesion work (Wadcal). A sandwich interface structure is observed, consisting of two interfaces: metal||CrmCn and CrmCn||Cgr. Sn content mainly affects the former. At metal||CrmCn, Sn exists in various forms (e.g., Cu-Sn solid solution, CuxSny compounds) in contact with CrmCn. To elucidate the wetting and bonding mechanisms of metal||CrmCn, simplified interfacial models are constructed and analyzed based on first-principles calculations of density functional theory (DFT). The trend of theoretically calculated results (sigma metal and Wad) agrees with the experimental results (sigma lv and Wadcal). Further analysis of the partial density of state (PDOS) and charge density difference (CDD) reveals that charge distribution and bonding characteristics vary with Sn content, providing the microscopic insight into the nature of wettability and interfacial bonding strength .
10.3390-ma18102310	14	strength; properties; conductivity; electrical; mechanical; cu-; grain; mpa; electrical conductivity; aging; precipitation; phase; mechanical properties; tensile; phases	Cu-Zn alloys are widely used engineering materials with well-known industrial applications. However, studies on their electrical and thermal conductivities have primarily relied on experimental measurements, while theoretical investigations remain limited. In this work, eight crystal structure models were constructed to represent three phase configurations (alpha single phase, alpha + beta ' dual phase, and beta ' single phase) of Cu-Zn alloys with Zn concentrations ranging from 0 to 50 at%. Based on the first-principles calculations combined with the Boltzmann transport equation, the electrical and thermal conductivities of these models were computed, and the electronic structure of the alpha-phase configurations was further analyzed. The results show that both electrical and thermal conductivities exhibit a non-monotonic trend with increasing Zn content, initially decreasing and then increasing. This trend is in strong agreement with available experimental data. Further analysis of the electronic structure reveals that, in the alpha-phase region, the density of states near the Fermi level is mainly contributed by Cu d-orbitals. As Zn content increases, the effective DOS near the Fermi level decreases, leading to reduced electron transport capability. For thermal conductivity, both the Wiedemann-Franz law and the first-principles calculations were employed, yielding results consistent with experimental trends. In summary, this study systematically investigates the variation of electrical and thermal conductivities of Cu-Zn binary alloys with Zn content and explores the underlying physical mechanisms from the perspective of electronic structure. The findings provide valuable theoretical support for understanding and optimizing the transport properties of complex alloy systems.
10.3390-ma18112438	-1		This study evaluates the wear and corrosion resistance of the Cu-50Ni-5Al alloy reinforced with CeO2 nanoparticles for potential use as anodes in molten carbonate fuel cells (MCFCs). Cu-50Ni-5Al alloys were synthesized, with and without the incorporation of 1% CeO2 nanoparticles, by the mechanical alloying method and spark plasma sintering (SPS). The samples were evaluated using a single scratch test with a cone-spherical diamond indenter under progressive normal loading conditions. A non-contact 3D surface profiler characterized the scratched surfaces to support the analysis. Progressive loading tests indicated a reduction of up to 50% in COF with 1% NPs, with specific values drop-ping from 0.48 in the unreinforced alloy to 0.25 in the CeO2-doped composite at 15 N of applied load. Furthermore, the introduction of CeO2 decreased scratch depths by 25%, indicating enhanced wear resistance. The electrochemical behavior of the samples was evaluated by electrochemical impedance spectroscopy (EIS) in a molten carbonate medium under a H-2/N-2 atmosphere at 550 degrees C for 120 h . Subsequently, the corrosion products were characterized using X-ray diffraction (XRD), scanning electron microscopy coupled with energy dispersive spectroscopy (SEM-EDS), and X-ray photoelectron spectroscopy (XPS). The results demonstrated that the CeO2-reinforced alloy exhibits superior electro-chemical stability in molten carbonate environments (Li2CO3-K2CO3) under an H-2/N-2 atmosphere at 550 degrees C for 120 h . A marked reduction in polarization resistance and a pronounced re-passivation effect were observed, suggesting enhanced anodic protection. This effect is attributed to the formation of aluminum and copper oxides in both compositions, together with the appearance of NiO as the predominant phase in the materials reinforced with nanoparticles in a hydrogen-reducing atmosphere. The addition of CeO2 nanoparticles significantly improves wear resistance and corrosion performance. Recognizing this effect is vital for creating strategies to enhance the material's durability in challenging environments like MCFC.
10.3390-ma18112489	-1		As a pioneering exploration of gallium nitride (GaN) as reinforcement in metal matrix composites, this study systematically investigated the mechanical-electrical property evolution in copper matrix composites through controlled GaN incorporation-a research gap scarcely addressed previously. GaN-Cu composites with tailored GaN contents were successfully synthesized by precisely controlled mechanical alloying and powder metallurgical processing and exhibited exceptional mechanical-electrical synergies. Advanced microstructural characterization via X-ray diffraction and electron microscopy revealed the homogeneous dispersion of GaN nanoparticles within the Cu matrix, forming coherent interfacial structures. The characterization results show that GaN-Cu composites could be successfully prepared by mechanical alloying and powder metallurgy methods, and it was confirmed that GaN nanoparticles could improve the mechanical properties of metal matrix composites as reinforcement; with an exponential increase in GaN content, the decrease in conductivity became very slow. With an increase in GaN content, the electrical conductivity decreased in an L shape, while the hardness first increased and then decreased, but the hardness could reach up to 128.66 HV, which is about 130% higher than that of the substrate.
10.3390-ma18112547	14	strength; properties; conductivity; electrical; mechanical; cu-; grain; mpa; electrical conductivity; aging; precipitation; phase; mechanical properties; tensile; phases	Cu-Fe in situ composites often face challenges in achieving high strength during cold rolling due to the inefficient transformation of partial Fe phases into fibrous structures. To uncover the underlying mechanisms, this study systematically investigates the co-deformation behavior of Cu and Fe phases in a Cu-10Fe alloy subjected to cold rolling at various strains. Through microstructure characterization, texture analysis, and mechanical property evaluation, we reveal that the Cu matrix initially accommodates most applied strain (epsilon(vm) < 1.0), forming shear bands, while Fe phases (dendrites and spherical particles) exhibit negligible deformation. At intermediate strains (1.0 < epsilon(vm) < 4.0), Fe phases begin to deform: dendrites elongate along the rolling direction, and spherical particles evolve into tadpole-like morphologies under localized shear. Concurrently, dynamic recrystallization occurs near Fe phases in the Cu matrix, generating ultrafine grains. Under high strains (epsilon(vm) > 4.0), Fe dendrites progressively transform into filaments, whereas spherical Fe particles develop long-tailed tadpole-like structures. Texture evolution indicates that Cu develops a typical copper-type rolling texture, while Fe forms alpha/gamma-fiber textures, albeit with sluggish texture development in Fe. The low efficiency of Fe fiber formation is attributed to the insufficient strength of the Cu matrix and the elongation resistance of spherical Fe particles. To optimize rolled Cu-Fe in situ composites, we propose strengthening the Cu matrix (via alloying/precipitation) and suppressing spherical Fe phases through solidification control. This work provides critical insights into enhancing Fe fiber formation in rolled Cu-Fe systems for high-performance applications.
10.3390-ma18112648	-1		Cu matrix composites, because of their high mechanical strength, are often used as conductors in high-performance electrical applications. These composites are manufactured through thermomechanical processing, which introduces a high density of particles that act as obstacles to dislocation motion. Increasing the density of these particles enhances the mechanical strength of the conductors, which we tested under static loading. Under cyclic loading, especially pulsed electrical mechanical loading, conductors may soften, harden, or even fail. Failure is likely to occur whenever the applied stress exceeds the flow stress of the conductors. Understanding and predicting the performance of conductors under cyclic loading can help researchers estimate the lifespan of any apparatus made from these conductors. The performance of conductors depends on whether the strengthening particles are characterized by ionic interatomic bonding or metallic bonding. During fabrication, we observed both the accumulation of dislocations and the dissolution of particles (which added more solute atoms to the matrix). Because both dislocations and solute atoms tend to migrate at room temperature or higher, the complexity of microstructure changes increases in composites under cyclic loading. To minimize such complexity, we designed our test to determine fatigue properties at 77 K. We subjected the conductors to cyclic fatigue tests using a load-controlled mode (the mode most commonly used in applications). This work sheds light on the correlation between tensile properties and fatigue properties in our composite conductors. We found that the correlation varied, depending on whether the conductors had been strengthened by ionic bond or metallic bond particles.
10.3390-ma18122678	14	strength; properties; conductivity; electrical; mechanical; cu-; grain; mpa; electrical conductivity; aging; precipitation; phase; mechanical properties; tensile; phases	This study systematically investigates the influence of different heat treatment processes on the microstructural evolution and mechanical properties of Cu-15Ni-3Al alloys, with particular emphasis on the synergistic strengthening mechanisms of spinodal decomposition and precipitation hardening. Two distinct aging routes-solution aging and direct aging-were designed to facilitate a comparative assessment of microstructural characteristics and their correlation with mechanical performance. Comprehensive characterization was conducted using scanning electron microscopy (SEM), X-ray diffraction (XRD), transmission electron microscopy (TEM), and room-temperature tensile testing to elucidate the structure-property relationships. The results reveal that direct aging promotes the formation of fine, coherent γ′-type Ni3Al precipitates and the evolution of Ni-enriched regions initially generated through spinodal decomposition into stable Ni3Al precipitates. These microstructural features act as effective barriers to dislocation motion, thereby significantly enhancing both strength and ductility. The findings provide valuable insights into optimizing heat treatment strategies to improve the performance of Cu-Ni-Al alloys.
10.3390-ma18133042	-1		Solid-state thermal decomposition in the Cu-13.3Ti-3.8Zr (at%) alloy was studied using a synthesized method, including the temperature-concentration gradient and differential scanning calorimetry experiments within a single experimental cycle, as well as first principle calculations. Experimentally, the decomposition pathway and the solid solubility of Ti/Zr in the Cu matrix in the temperature range of 820 degrees C to 801.5 degrees C were observed in the Cu-13.3Ti-3.8Zr (at%) alloy. The primary solid phase is (Cu) phase and subsequently precipitated Cu51Zr14 and Cu4Ti phases. These features are valuable for understanding the thermal stability and solid-state phase equilibria of the alloy. First principle calculations, including formation enthalpy, charge density, and electron localization function analyses, were conducted to evaluate the thermal, structural, and electrical stability of Cu51Zr14 with and without Ti doping, as well as Cu4Ti. The present work introduces an effective strategy for determining both the solid-state thermal decomposition pathway and the phase diagram within the solid-state region within a single experimental cycle.
10.3390-ma18174197	-1		Additive manufacturing techniques, such as selective laser melting (SLM), enable the production of intricate and integrated components made from metallic materials with inherent porosity. The pores, typically perceived as defects, are commonly observed on the surface or within the matrix of SLM-formed components. However, it is noteworthy that these pores can function as reservoirs for lubricants to enhance tribological performance in specific applications, such as porous bearings. In this study, the optimum conditions for fabricating Cu-15Ni-8Sn alloy porous bearings via SLM technology were investigated. By regulating laser power and hatch space during SLM processing, Cu-15Ni-8Sn alloy porous bearings were successfully obtained. The resulting oil bearings exhibited an oil content exceeding 18% and a radial crushing strength surpassing 370 MPa. At reduced laser power (80 W) and increased hatch spacing (0.9 mm), average friction coefficients of 0.1 and 0.13 were observed, with volumetric wear values of 10.3 mm3 and 96.7 mm3, respectively. The friction mechanism is a combination of abrasive wear and delamination wear.
10.3390-ma18184288	-1		Cu-Ni-Al cupronickel alloy is a precipitation-strengthening alloy with gamma ' (Ni3Al) and gamma '' (Ni3Nb) phases embedded in the gamma phase (Cu solid solution), enhancing strength and corrosion resistance. However, it is difficult to clarify the correlation between composition and properties due to the complex elements and microstructure. This study attempts to construct the composition formulas and microstructure constitution (e.g., phase volume fractions) of Cu-Ni-Al cupronickel alloys via the cluster plus glue atoms model. Based on the solubility behavior of alloying elements, a systematic classification was established as follows: gamma phase elements (Cu-like elements, including Cu, Ni, Al, Mg, Mn); gamma ' phase elements: Al-like elements (including Al, Nb, Si, Cr, Mn, Fe); and Ni-like elements (including Ni, Fe, Cu). Using this classification and phase composition (gamma and gamma ' phase under heat-treated conditions), the cluster formula of the structural units that carry the composition information were formulated as follows: gamma-{(Cu,Ni,Al,Mn,Mg)16}1-x and (gamma ' + gamma '')-{(Al,Nb,Si,Cr,Mn,Fe)4(Ni,Fe)8Cu4}x, where x represents the volume fraction of precipitates (gamma ' + gamma ''). The representative Cu-Ni-Al cupronickel alloys were also analyzed by the cluster formula, and theoretical phase volume fractions were obtained (13.21-26.32%). Furthermore, Young's modulus, predicted by the cluster formula, shows good agreement with the practical alloys, verifying its applicability for alloy design.
10.3390-ma18194436	-1		This work reports on a systematic investigation of the microstructure and comprehensive performance of Cu-Fe immiscible composite coatings prepared through the combination of mechanical alloying and laser cladding. The samples were characterized by scanning electron microscopy with an energy dispersive analysis, X-ray diffraction, a digital microhardness tester, a current tester, an electrochemical analyzer, and a magnetometer. The results show that the immiscible composite coatings are mainly composed of alpha-Fe particle dispersion in the epsilon-Cu matrix due to liquid phase separation, and this is exacerbated by the addition of more Fe content. Concentrated distribution of Fe-rich particles at either the top or bottom of the immiscible composite coatings is driven by the dominant mechanism of Marangoni and Stokes motion. With the increased fraction of Fe content, the microhardness and electrical resistivity increased, but with a degradation in corrosion resistance. With the increased ball milling time, the electrical resistivity increased, and the corrosion resistance improved. Compared to the medium-carbon steel substrate, the immiscible composite coatings can achieve an improved corrosion resistance, as well as a maximum saturated magnetization of 10.172 emu/g and the lowest coercivity at 17.249 Oe.
10.3390-ma18204772	-1		Cu-Ni-Si alloys are advanced materials for electronic applications combining high mechanical strength and electrical conductivity through precipitation of fine Ni silicides. Increasing the Ni content-and, thus, the Ni:Si ratio-enhances the volume fraction of strengthening precipitates. However, the conventional fabrication route is time-consuming and costly, as the slow cooling rates lead to a coarse microstructure and pronounced segregation, limiting Ni and Si content to 5 wt%. Rapid solidification techniques offer a promising alternative, since the higher cooling rates refine the microstructure while suppressing the elemental segregation. This study presents a novel powder-based approach to overcome the compositional limitations of Cu-Ni-Si alloys, providing a pathway for faster alloy screening. Two gas-atomized powders with different Ni contents-CuNi3Si1.5 and CuNi10Si1.5 (wt%)-were engineered as feedstock for laser powder bed fusion, produced, and characterized to assess the effect of the Ni level on the microstructure and properties. Gas-atomization yielded spherical powders with a fine dendritic structure and limited segregation. Increased Ni content enhanced strengthening mechanisms and hardness, as well as improved optical response, suggesting the potential of high-Ni Cu-Ni-Si compositions for use in laser powder bed fusion.
10.3390-ma5122439	2	corrosion; surface; film; electrochemical; films; spectroscopy; layer; current; solution; potential; resistance; composition; x-ray; ions; showed	The effects of pH and chloride concentration on the electrochemical corrosion of copper in aqueous sodium chloride (NaCl) media were studied at the micro scale using a microcapillary droplet cell and at the macro scale using a conventional large scale cell. Using an experimental design strategy, electrochemical response surface models of copper versus pH and NaCl concentration were constructed with the minimum number of experiments required. Results show that the electrochemical behavior of copper under corrosive media shows significant differences between the micro and macro scale experiments. At the micro scale, the pit initiation of copper occurs at more negative potentials for high NaCl concentrations and alkaline pH values. Also, the micro scale potentiostatic measurements indicate higher stabilised passive currents at high NaCl concentrations and low (acidic) pH values. At the macro scale, the pH is shown to have a greater influence on the corrosion potential. The chloride concentration is the most significant factor in the passive current case while at the micro scale the effect of these two factors on the passive current was found to be the same. The surface morphology of the formed patina on the corroded copper in both micro and macro systems reveal a more significant role of the chloride concentration on the structure and the grain size of the patinas. Finally, micro and macro electrochemical impedance spectroscopy of copper at various NaCl concentrations and pH values demonstrates a different behavior of copper after several potentiodynamic polarization cycles.
10.3390-ma8095290	2	corrosion; surface; film; electrochemical; films; spectroscopy; layer; current; solution; potential; resistance; composition; x-ray; ions; showed	This paper studies the corrosion behavior of B10 copper-nickel alloy in marine environment. Accelerated degradation test under marine environmental conditions was designed and performed based on the accelerated testing principle and the corrosion degradation mechanism. With the prolongation of marine corrosion time, the thickness of Cu2O film increased gradually. Its corrosion product was Cu-2(OH)(3)Cl, which increased in quantity over time. Cl- was the major factor responsible for the marine corrosion of copper and copper alloy. Through the nonlinear fitting of corrosion rate and corrosion quantity (corrosion weight loss), degradation data of different corrosion cycles, the quantitative effects of two major factors, i.e., dissolved oxygen (DO) and corrosion medium temperature, on corrosion behavior of copper alloy were analyzed. The corrosion failure prediction models under different ambient conditions were built. One-day corrosion weight loss under oxygenated stirring conditions was equivalent to 1.31-day weight loss under stationary conditions, and the corrosion rate under oxygenated conditions was 1.31 times higher than that under stationary conditions. In addition, corrosion medium temperature had a significant effect on the corrosion of B10 copper sheet.
10.3390-machines11090881	-1		Copper (I) sulfide (Cu2S) is a low-cost, earth-abundant, and non-toxic thermoelectric material for applications in the middle-high temperature range (>650 K). Although 3D printing these materials can simplify their manufacturing, elevated temperatures observed during sintering impair their crystal structure and energy conversion efficiency. In this study, we demonstrated a novel post-processing methodology to revert the thermoelectric properties of the 3D printed Cu2-xS materials back to the unimpaired state via sulfur infusion. After printing and sintering, sulfur was infused into the specimens under vacuum to optimize their crystal structure and achieve high thermoelectric efficiency. Chemical analysis and X-ray Diffraction (XRD) tests showed that after the sulfur infusion process, the Cu/S ratio was reverted close to the stoichiometric level. The 3D printed Cu2-xS showed p-type thermoelectric behavior with electrical conductivity peaking at 143 S-cm(-1) at 750 K and Seebeck coefficient of 175 mu V-K-1 at 627 K. The figure of merit (ZT) value of 1.0 at 780 K was achieved, which is the highest value ever reported for a 3D printed Cu2-xS thermoelectrics at this temperature. The fabrication of environmentally friendly thermoelectric materials with extended dimensional freedom and conversion efficiency has the potential to impact the thermoelectric industry with new energy conversion applications and lowered manufacturing costs.
10.3390-magnetochemistry5030048	4	transformation; martensite; martensitic; phase; shape; beta; memory; shape memory; temperature; temperatures; martensitic transformation; gamma; transformation temperatures; effect; thermal	First-order phase transitions (FOPT) and second-order phase transitions (SOPT) are commonly observed in Cu alloys containing lanthanide elements, due to their electronic configuration, and have an important effect on the optimization of their magnetocaloric effect (MCE). Alloys containing rare earths have the best magnetocaloric response; however, these elements are very expensive, due to their obtaining and processing methods. The present work reports the effect of using 3d transition elements and thermal treatments on the microstructure and MCE of Cu-11A1-9Zn alloys with 6.5 wt% Ni and 2.5 wt% Fe. It was found that thermal treatments of quenching and normalizing, as well as the use of Ni and Fe, have an important influence on both the resulting phases and MCE of the investigated alloy. MCE was calculated indirectly from the change in the magnetic entropy ( -Delta S-m) under isothermal conditions, using Maxwell's relation; it was found that samples subjected to normalizing presented a higher magnetocaloric effect than samples with quenching, which was related to the greater disorder in the alloy, due to the coexistence of beta(1) + beta phases.
10.3390-met10020219	4	transformation; martensite; martensitic; phase; shape; beta; memory; shape memory; temperature; temperatures; martensitic transformation; gamma; transformation temperatures; effect; thermal	Monocrystalline alloy with a nominal composition of Cu-13.7% Al-4.2% Ni (wt%) that shows reversible martensitic transformations (RMTs) was studied. The alloy, manufactured by the Memory Crystals Group in Russia, was subjected to thermo-cyclical treatment (TCT) under tension within a range that included critical RMT temperatures. A special device was developed to perform TCTs (up to 500 cycles) and three different loads were applied: 0.11, 0.26, and 0.53 MPa. X-ray diffraction analysis, optical microscopy, differential calorimetry, and Vickers microhardness were involved in the alloy's characterization. Under TCTs, the alloy displayed complex structural transformation, revealing the sequence of RMT, beta(1) <-> R <-> beta'(1) + gamma'(1); the involved phases were coherently precipitated but very sensitive to the experimental conditions. It was found that during TCTs (from 300 cycles) performed under optimum load (0.26 MPa), the processes of martensite reorientation, hardening, and stabilization of the structure were the most intensive thus leading to a reduction of RMT critical intervals and increased microhardness.
10.3390-met10020241	-1		The microstructure and mechanical properties of cold-rolled Cu-2.7Be sheets under various annealing processes and conditions were investigated in this research . The increased beryllium content in the Cu-2.7Be alloy facilitates the formation of brittle secondary phases. Consequently, the study highlights the functionality of annealed Cu-2.7Be alloys as more favorable dynodes than the traditionally used Cu-2.0Be alloys. The mechanism of recrystallization used for the transformation of Cu-2.7Be alloys was that of continuous static recrystallization (cSRX). Moreover, the relationship between the orientation of the beta phases and that of the surrounding Cu-matrix was determined to be (11 (1) over bar)(alpha)parallel to(110)(beta) and (011)(alpha)parallel to(001)(beta). The beta phase has a body-centered cubic (bcc) structure with a = b = c = 0.281 nm. The beta phase undergoes a morphology transformation from primitive lath-shaped beta particles to quadrangle-shaped beta particles during the annealing process. Such transformations could potentially have an effect on the mechanical properties of Cu-2.7Be sheets. There was a noticeable decline in the yield strength of the Cu-2.7Be after annealing, and the samples annealed at 770 degrees C for 15 min achieved the elongation with deep and uniform dimples caused by suitable beta particle sizes, appropriate grain sizes, and the maximum volume fraction of Sigma 3 boundaries.
10.3390-met10050602	-1		During the high pressure die casting process (HPDC), it is necessary to develop new designs and alloys for the copper plungers. In this research, two alloys Cu-9Ni-1Co-1.6Cr-2Si-1.3Fe-0.25B wt% (A1) and Cu-9Ni-1Co-1.6Cr-2Si-0.1Fe-0.2Nb wt% (A2) under different heat treatments (HT) were studied. Optical microscopy technique was applied to reveal the regions of dendritic morphology, also lower Secondary Dendrite Arm Spacing (SDAS); and different grain orientations. The results reveal that the solidification sequence is primary Cu dendrites and secondary intermetallics; heat treatments increase the redistribution of alloying elements in the interdendritic regions. During the heat treatments, some precipitates were found in the grain boundary after aging heat treatments for both alloys, which were determined by X-ray diffraction. Hardness test HRB presented a decrease with the solution heat treatment and an increase with the aging heat treatments proposed for both alloys. Finally, the wear resistances for both alloys were compared with a commercial alloy C17530, with decreased A1 with B additions having the best result in the as-cast condition 4.07 x 10(-4) mm(3)/Nm, while for A2 with Nb additions wear resistance increased, with the best result in the one with aging heat treatment 1.69 x 10(-4) mm(3)/Nm while for the C17530 alloy this was 2.74 x 10(-4) mm(3)/Nm.
10.3390-met10050654	-1		Ultra-fine-grained (UFG) Cu shows little total elongation in tensile tests because simple shear deformation is concentrated in narrow regions during the initial stage of plastic deformation. Here, we attempted to improve the total elongation of UFG Cu obtained by equal-channel angular pressing. By making shallow dents on the side surfaces of the plate-like specimens, this induced pure shear deformation and increased their total elongation. During the tensile tests, we observed the overall and local deformation of the dented and undented UFG Cu specimens. Using three-dimensional digital image correlation, we found that the dented specimens showed suppression of thickness reduction and delay in fracture by enhancement of pure shear deformation. However, the dented and undented specimens had the same ultimate tensile strength . These results provide us a new concept to increase total elongation of UFG materials.
10.3390-met10060719	-1		This paper presents thermochemical synthesis of copper/alumina nanocomposites in a Cu-Al(2)O(3)system with 1-2.5 wt% of alumina and their characterization, which included: transmission electron microscopy: focused ion beam (FIB), analytical electron microscopy (AEM) and high resolution transmission electron microscopy (HRTEM). Thermodynamic analysis was used to study the formation mechanism of desirable products during drying, thermal decomposition and reduction processes. Upon synthesis of powders, samples were cold pressed (2 GPa) in tools dimension 8 x 32 x 2 mm and sintered at temperatures within the range 800-1000 degrees C for 15 to 120 min in a hydrogen atmosphere. Results of characterization showed that dispersion-strengthened compacts could be produced by sintering of thermo-chemically prepared Cu-Al(2)O(3)powders with properties suitable for material application, such as a contact material exhibiting high strength and high electrical conductivity at the same time. Additional research was carried out in order to analyze the application of the obtained nanocomposite powders for the synthesis of copper/alumina nanocomposites by a new method, which is a combination of a thermochemical procedure and mechanical alloying. The measured values of an electric conductivity and hardness were compared with ones in literature, confirming an advantage of the proposed combined strategy.
10.3390-met10111528	15	aging; strength; conductivity; electrical conductivity; electrical; mpa; treatment; strengthening; degrees; cu-; cold; precipitation; tensile strength; tensile; iacs	A novel compact preparation process has been developed to produce a Cu-20Ni-20Mn alloy. This process involves heating-cooling combined mould (HCCM) continuous casting, a solution treatment at 800 degrees C, rolling at room temperature and a final ageing step at 450 degrees C. This process eliminates two hot deformation processes, namely, hot forging and hot rolling, greatly improving production efficiency and reducing production costs compared with the traditional preparation process. The alloy fabricated by this process was found to have excellent mechanical properties. Additionally, the formation of precipitated phases during the ageing step is accelerated by this new process. The hardness of the samples reaches 476 HV after ageing for 10 h . Stable, ordered precipitates of Ni3Mn(γ′ phase) are observed in the rolled specimen, and the orientation relationship between the copper matrix and ordered Ni3Mn phase (γ′ phase) is [200](Cu)//[010](Ni3Mn) and [011](Cu)//[011](Ni3Mn). Precipitation strengthening is the main reason for the increase of strength of the sample during the ageing process. The mechanical properties and ageing precipitation process of the alloy are affected by the rolling process. The precipitation rate of the rolled sample is greatly increased during the ageing process, leading to a larger amount of precipitates.
10.3390-met11010039	-1		To apply the electric component with high efficiency, the softening problem of material should be improved. Cu-Cr alloys are recognized to be proper materials to be applied. However, the softening problem has not been solved yet. In this study, the effect of Ti and Al on mechanical property and electrical conductivity in Cu-Cr alloy was investigated. Cr content is designed to up to 0.25 wt% in order to be expected to improve electrical conductivity. During fabrication processing, microstructure identification, Cr concentration, lattice parameter, and micro-hardness in copper matrix were measured. Then, aging condition was investigated. Resistance about over-aging is increased compared to Cu-Cr and Cu-Cr-Al alloy added to Ti. The hardness and electrical conductivity are discussed by the working conditions and heat treatment, such as rolling, solid-solution treatment, and aging process, which improve the formability also at the optimum condition. Moreover, the role of Ti contents is studied. In the Cu-Cr alloys, the addition of both Al and Ti contents keeps the hardness from being reduced. As a result, the precipitation of Cr particles and the obstacle by Al and Ti contents to be softened are observed in this study.
10.3390-met11010141	-1		Spark plasma sintering (SPS) is widely used for the consolidation of different materials. Copper-based pseudo alloys have found a variety of applications including as electrodes in vacuum interrupters of high-voltage electric circuits. How does the kinetics of SPS consolidation for such alloys depend on the heating rate? Do SPS kinetics depend on the microstructure of the media to be sintered? These questions were addressed by the investigation of SPS kinetics in the heating rate range of 0.1 to 50 K/s. The latter conditions were achieved through flash spark plasma sintering (FSPS). We also compared the sintering kinetics for the conventional copper-chromium mixture and for the mechanically induced copper/chromium nanostructured particles. It was shown that, under FSPS conditions, the observed maximum consolidation rates were 20-30 times higher than that for conventional SPS with a heating rate of 100 K/min. Under the investigated conditions, the sintering rate for mechanically induced composite Cu/Cr particles was 2-4 times higher compared to the conventional Cu + Cr mixtures. The apparent sintering activation energy for the Cu/Cr powder was twice less than that for Cu-Cr mixture. It was concluded that the FSPS of nanostructured powders is an efficient approach for the fabrication of pseudo-alloys.
10.3390-met11040656	-1		Friction stir processing (FSP), a severe plastic deformation process, was applied on pure Cu to obtain a stir zone with a very fine grain size. Yet, when FSP is used, the stir zone is as wide as the diameter of the shoulder at the upper surface of the weld and markedly narrower near its opposite surface. This property, as well as the differences between the advancing side and the retreating side, makes it impossible to obtain a uniform cross-section as far as the microstructure and mechanical properties are concerned. For these reasons, a new approach is proposed in which the material was processed on both sides, thus yielding a wider, rectangular and more homogenous stir zone from which all the specimens were machined out. Processing the material from both sides eliminated any microstructural difference between the upper and the lower side, at least within the gauge length's cross-section of the creep specimens. Although grain refinement was detected, the mechanical properties of the friction-stir-processed (FSP'ed) material are inferior relative to those of the parent material. The TEM study reported in the current paper revealed the existence of nanosized grains in the FSP'ed material due to dynamic recrystallization (DRX) occurring during the processing stage. Because both X-ray inspection and fractography showed that the FSP'ed material was free of defects, the material may not comply with the Hall-Petch relation due to lower dislocation density caused by XRD occurring during FSP. The inverse Hall-Petch effect may also be considered as an assistive mechanism in mechanical property deterioration.
10.3390-met11071010	-1		We investigated the effectiveness of severe plastic deformation by equal channel angular extrusion (ECAE) for consolidation of metal powders into metal matrix composites. Equal volumes of copper (Cu) and tantalum (Ta) powders were consolidated at ambient temperature via different ECAE routes. Composites processed by ECAE routes 4E and 4Bc were also processed at 300 degrees C. The resulting materials were characterized by scanning electron microscopy (SEM) and compression testing. Processing by route 4Bc at 300 degrees C resulted in the highest compressive strength, lowest anisotropy, and least strain rate sensitivity. We conclude that the superior properties achieved by this route arise from mechanical bonding due to interlocking Cu and Ta phases as well as enhanced metallurgical bonds from contact of pristine metal surfaces when the material is sheared along orthogonal planes.
10.3390-met11091410	-1		Laser powder bed fusion (LPBF) technology is beneficial for the fabrication of thermal conductive materials, integrating with the predesigned structure, which shows a great potential for high heat dissipation applications. Here, a Cu-Cr-Zr alloy with relative density of 98.53% is successfully prepared by LPBF after process optimization. On this basis, microstructure, phase identification, precipitates, mechanical and thermal properties are investigated. The results demonstrate that the surface morphology of microstructure is affected by laser energy density, the alpha-Cu is the main phase of the LPBF sample and the virgin powder, the size of Cr spherical precipitates in some areas is about 1 mu m, and the tensile fracture mode is a mixed ductile-brittle mode. Furthermore, the Vickers hardness of the LPBF Cu-Cr-Zr sample is 70.7 HV to 106.1 HV, which is higher than that of LPBF Cu and a wrought C11000 Cu, and the difference in Vickers hardness of different planes reflects the anisotropy. Ultimately, the two types of Cu-Cr-Zr alloy heat sinks are successfully fabricated, and their heat transfer coefficients are positively correlated with the volume flow. The heat dissipation performance of the cylindrical micro-needle heat sink is better, and its maximum heat transfer coefficient is 3887 W/(m(2)center dot K).
10.3390-met11111795	-1		The quantitative concentration of alloying elements in low-alloyed copper alloys is an important factor in forming electrical and mechanical characteristics. It is known that severe plastic deformation is accompanied by both a substantial refinement of the structure and changes in the kinetics of phase transformations during the deformation and the post-deformation thermal treatment. This paper presents the results of a comparative analysis of the Cu-0.2Cr and Cu-1.1Cr alloys subjected to equal-channel angular pressing at room temperature. The analysis was performed for the grain structure, solid solution, and second-phase particles using transmission electron microscopy, scanning electron microscopy, X-ray crystal analysis, and the small-angle diffraction method. It was found that the level of structure refinement and mechanical characteristics after equal-channel angular pressing was almost the same for both studied alloys. Post-deformation aging of the Cu-0.2Cr alloy leads to the development of polygonization and re-crystallization within it. The aging of the Cu-1.1Cr alloy shows a better thermal stability than that of the Cu-0.2Cr alloy. In the Cu-1.1Cr alloy, after aging, in comparison with Cu-0.2Cr, a denser-packed ensemble of fine particles with an average size of 54 & PLUSMN; 2 nm is formed. In this case, the average size of fragments is 270 & PLUSMN; 15 nm and the ultimate tensile strength reaches 485 MPa.
10.3390-met11121883	-1		Pure Copper (Cu) is very difficult to prepare using selective laser melting (SLM) technology. This work successfully prepared the pure Cu with high relative density and high strength by the SLM technology using a surface oxidation treatment. The gas-atomized pure Cu powder was used as the feedstock in this work. Before the SLM process, the pure Cu powder was initially handled using the surface oxidation treatment to coat the powder with an extremely thin layer of Cu2O. The SLMed highly dense specimens contain alpha-Cu and nano-Cu2O phases. A relationship between the processing parameters (laser power (LP), scanning speed (SS), and hatch space (HS)) and density of Cu alloy in SLM was also investigated. The microstructure of SLMed Cu consists of fine grains with grain sizes ranging from 0.5 to ~30 mu m. Tensile testing and detailed microstructural characterization were performed on specimens in the as-SLMed and pure copper state specimens. The mechanical property experiments showed that the specimens prepared by SLM technology containing nano-oxide phases had higher yield strength and tensile strength than that of other SLM-built pure copper. However, the elongation was remarkably decreased compared to other SLM-built pure copper, due to the fine grains and the nano-oxides.
10.3390-met12010074	-1		The processing of polymetallic materials provides some challenges to every flowsheet. Within Aurubis Cu-Pb-metallurgical flowsheet, a broad range of raw materials and intermediates are processed. Continuous improvements are required to adapt the flowsheet according to the changing material quantity and quality. Therefore, thermodynamic modeling is the desired and most efficient way to conduct scenario analysis. Hence, databases and software are becoming better and better as the acceptance of this method increased. Further understanding is promoted by conducting experimental test work to validate the calculated results. In this research work, the impact of various oxygen potential on the formation of the condensed phases' slag, matte, speiss and crude lead were investigated. A frequent check of slag metallurgy, in particular, the iron and lead concentration, provide feedback if the metallurgical process is operating at the right oxygen potential. Following, the calculated distribution coefficients for Cu, Pb, As, Sb, Sn and Ni between matte/speiss and speiss/lead are discussed.
10.3390-met12040592	-1		In order to achieve a reasonable balance between the high electrical conductivity and high tensile strength of TiB2 particles (TiB2p) and TiB whiskers (TiBw) reinforced copper matrix composites prepared by in situ reaction casting, the effects of reaction temperature and heat treatment time on the electrical conductivity and tensile strength of composites were studied. The results show that the electrical conductivity increased while the tensile strength decreased with the increase in reaction temperature from 1300 degrees C to 1500 degrees C. With the increase in heat treatment time, the electrical conductivity increased, while the tensile strength of the composites increased first and then decreased. The electrical conductivity and tensile strength of composites are related to the degree of in situ reaction at liquid or solid state, and the reasons for the improved performance are also discussed. Finally, two optimized preparation processes are proposed by cooperative controlling the reaction temperature and heat treatment time, the comprehensive properties of (TiB2p+TiBw)/Cu composites are 79.6% IACS/603 MPa and 83.7% IACS/602 MPa, respectively.
10.3390-met12091401	12	thermodynamic; ternary; phase; data; experimental; equilibria; phase equilibria; liquid; binary; experimental data; calculated; phases; literature; model; calphad	In our study, a complete review of the literature, critical evaluation and thermodynamic assessment of the Cu-Zn, Cu-Se and Zn-Se binary systems were carried out. The modified quasi-chemical model (MQM) was applied to describe the Gibbs energy of the liquid phase. The Gibbs energies of all intermetallic compounds and terminal solid solutions were described using the compound energy formalism (CEF) model. The re-optimization of the Cu-Zn binary system was carried out by considering the ordered bcc_B2 crystal structure of the beta' phase. Moreover, the beta and delta phases in the Cu-Zn binary system with the same bcc_A2 crystal structure were modeled as one single phase in the present work. A self-consistent thermodynamic database was constructed for the Cu-Zn, Cu-Se and Zn-Se binary systems, work that formed part of a comprehensive thermodynamic database development project researching zinc-based biodegradable materials.
10.3390-met12091473	2	corrosion; surface; film; electrochemical; films; spectroscopy; layer; current; solution; potential; resistance; composition; x-ray; ions; showed	The influence of annealing treatment on the microstructure and the corrosion behaviour of a complex bronze Al-Ni alloy was analysed. The microstructural characterization after thermic treatment shows that the retained beta-phase disappears and the K-II-phase undergoes a spheroidization process. Moreover, there is an augmentation of K-phase precipitates within the alpha-phase, particularly K-IV and K-V, which homogenizes the distribution of alloying elements between the phases. The corrosion behaviour was investigated by means of selective corrosion tests, potentiodynamic measurements, and electrochemical impedance spectroscopy. All of the experiments showed that thermic treatment greatly improves the corrosion resistance of the alloy. As such, annealing treatment influences a microstructure to be more dealloying resistant, which allows the development of a more protective air-formed passive film. On the other hand, the lower current registered after anodic peaks and Electrochemical Impedance Spectroscopy data seem be correlated with a more protective layer formed on annealed material. As such, this protective character is due to a greater incorporation of Al3+, Ni2+ and Cu2+ in the passive film, as revealed by X-ray Photoelectron Spectroscopy results.
10.3390-met12091522	-1		Cu-W composite powder with various W contents (0, 10, 20, and 30 wt%) has been fabricated by spray drying, calcination, and two-stage hydrogen reduction in this work. The microstructures and phase evolution of Cu-W composite powder were studied by FESEM, HRTEM, and XRD. Results show that precursor powder is composed of Cu-2(OH)(3)NO3 and H2WO4 center dot H2O. Spherical CuWO4 with a particle size of about 50 nm and micron-scale flat flake CuO were obtained when the calcination temperature was 500 degrees C. Through chemical vapor transport (CVT) during the reduction process, volatile WO2(OH)(2) continuously migrates to the copper surface and is reduced to W, resulting in a W-coated Cu structure. This coating structure can inhibit the aggregation and growth of copper particles. The particle sizes of Cu-10 wt%W, Cu-20 wt%W, and Cu-30 wt%W composite powders are 9.309 mu m, 8.440 mu m, and 6.290 mu m, reduced by 40.51%, 46.06%, and 59.80%, respectively, compared to the particle size of pure copper powder, 15.648 mu m. With increasing W content, the W-coated Cu particles gradually become denser and trend to grow from sphere to flake.
10.3390-met12101622	-1		The present work aims to systematically investigate the influence of P content on the microstructure and texture evolution of oxygen-free copper during intermediate annealing and final cold rolling. The microstructure and texture evolution were studied by electron backscattered diffraction and transmission electron microscopy. With the addition of P, the grains refined and a large fraction of low angle grain boundaries (LAGBs) emerged after intermediate annealing. The texture transformed from pure metal type for pure Cu to the alpha-fiber texture which included brass and Goss texture as P was added. The recrystallization temperature increased with the addition of P, and refined grains after the final cold rolling process. The addition of elemental P would reduce the stacking fault energy, and then influence the transformation of the deformation and recrystallization texture of the copper. Accompanied by the evolution of the deformation texture, the recrystallization cubic texture {001} was suppressed and a strong {236} brass recrystallization texture emerged with the addition of elemental P after the intermediate annealing and subsequent final cold rolling process.
10.3390-met12101653	12	thermodynamic; ternary; phase; data; experimental; equilibria; phase equilibria; liquid; binary; experimental data; calculated; phases; literature; model; calphad	The effect of dilute solute additions on growth restriction in Cu-, Al-, Mg- and Ti-based binary and ternary alloys was assessed by means of the heuristic growth restriction parameter (beta) modelling framework. The CALPHAD (calculation of phase diagrams) methodology was used to calculate beta values from the m and k values, at first approximation, as well as from the liquid-to-solid fraction to obtain true beta values. Grain size values from the literature were plotted against the corresponding true beta values, showing a negative or inverse correlation between the two.
10.3390-met13010150	-1		Copper alloys with chromium, hafnium, and scandium combining enhanced strength as well as high electrical and thermal conductivity are analyzed in depth . The aim is to compare the precipitation process during temperature exposure to meet increasing material requirements. This research focuses on alloying elements having a limited, maximum 1 wt%, and with temperature decreasing solubility in copper. For the simultaneous enhancement of mechanical strength and conductivity, precipitation hardening is the utilized mechanism during the processing of as-casted annealed and quenched specimens and in combination with optional cold-rolling prior to the aging process. Extensive DSC measurements, accompanied by metallographic investigations, and the analysis of hardness and electrical conductivity, lead to a versatile description and comparison of different alloying systems. CuCr0.7 starts to precipitate early and is mainly influenced by the temperature of aging. Provoking the solid solution with cold deformation has a less significant influence on the following precipitation. CuSc0.3 and CuHf0.7 precipitate at higher temperatures and are highly influenced by cold deformation prior to aging. Furthermore, CuHf0.7 and CuSc0.3 show advantages regarding the recrystallization behavior, making them especially applicable for higher operating temperatures. Future research will assess ternary alloy combinations to further scoop the potential.
10.3390-met13020338	-1		When ceramic particles are incoherent with copper matrices, or when large coherent strains exist due to the differences between their crystal structure and lattice parameters in traditional dispersion-strengthened copper alloys, the strengthening effect of dispersoids at high temperatures is reduced. In the present work, a Cu-0.48Al-3.5Yb(2)O(3) alloy was fabricated by mechanical alloying and spark plasma sintering. The investigation results prove that completely coherent inert ceramic particle YbAlO3 without coherent strains is introduced into the copper matrix. The microstructural evolution and thermal stability of the alloy after annealing at high temperatures are investigated and discussed, and it is found that the alloys exposed at 600 similar to 800 degrees C for 3 h exhibit excellent thermal stability and exceptional structural stability. The exceptional resistance to grain growth in the alloy can be attributed to the Zener pinning effect provided by the fine dispersion of YbAlO3 particles. High-density geometrically necessary dislocation (GND) is retained in the alloy even after annealing at 800 degrees C for 3 h, as is the presence of parallel GND rows because they do not easily react with opposite rows to annihilate the dislocation. At the same time, dispersed YbAlO3 acts as a strong obstacle to moving the GND. The present work proves that the structural stability of copper can be significantly improved by introducing completely coherent dispersed particles.
10.3390-met13030451	-1		The coefficient of linear thermal expansion and the specific heat capacity of laser-deposited Cu-Fe alloys fabricated from tin, aluminum, chromium bronze (89-99 wt% Cu), and SS 316L were studied. The investigated alloys had a 1:1 and a 3:1 bronze-steel ratio. The Al-bronze-based alloy showed the lowest value of linear thermal expansion coefficient: (1.212 +/- 0.095)center dot 10(-5) K-1. Contrarily, this value was the highest {[(1.878-1.959) +/- 0.095]center dot 10(-5) K-1} in the case of functionally graded parts created from alternating layers of bronze and steel. Differential scanning calorimetry provided experimental results about the specific heat capacity of the materials. In the case of Al-bronze-based specimens, it demonstrated a decrease in the specific heat capacity until similar to 260 degrees C and its further increase during a heating cycle. Exothermic peaks related to polymorphic transformations were observed in the Al-bronze-based specimens. Cooling cycles showed monotonous behavior for specific heat capacities. It had exothermic peaks in the case of Cr-bronze-based alloys. A Lennard-Jones potential equation was used for testing the relation between heat capacity and thermal expansion. A three-way interaction regression model validated the results and provided the relative thermal expansion of commercially pure DED-fabricated SS 316L. Its specific heat capacity was also studied experimentally and was 15-20% higher in comparison to the traditional method of production.
10.3390-met13030459	-1		Cu-11Al-5Ni-4Fe wt% alloy is processed by additive manufacturing using the laser powder bed fusion (LPBF) technique in two building orientations (90 degrees and 0 degrees to the building platform) to determine which laser parameters are more critical to obtain better mechanical properties. The resulting printed material is characterized microstructurally and mechanically by XRD, optical microscope, and under compressive stress. The results indicate that the alloy achieved good densification and mechanical properties similar to an as-cast counterpart. The as-built microstructure comprises acicular martensite and other thermodynamic equilibrium phases, while exothermic and endothermic curves show a poor response to temperature induce phase transformation at similar to 350 degrees C. The mechanical results show that it is possible to reach a compressive strength of 1300 MPa, up to 20% strain, and better mechanical properties in those samples fabricated in a vertical direction (90 degrees) than the horizontal. The volumetric energy density also affects the samples' maximum strength and superficial roughness.
10.3390-met13030581	-1		The performance of Cu-Fe alloy is related to the solidification structure, which is directly determined by the microstructure evolution during solidification. The solidification sequence, solid-liquid interface variation, and microstructural evolution of Cu-20wt%Fe alloy at three cooling rates (0.3, 1.5, and 5.0 degrees C/s) were investigated. The results indicate that the remelting of primary gamma-Fe dendrites was directly observed through the solidification experiment, and the partial gamma-Fe dendrite was fragmented owing to remelting. The Fe phase morphology changed from the cellular structure to the typical finer and longer dendrite structure with the cooling rate increasing. As the cooling rate increased, the constitutional undercooling caused by the decrease in the Fe atom concentration and the increase in the Cu atom concentration increased in the solidifying interface. There was a parabolic relationship between the growth rate of the dendrite tip and time. Meanwhile, the growth of the primary gamma-Fe phase was inhibited by the insufficient diffusion of Fe and Cu at the solidification front, which resulted in a decrease in the Fe phase volume fraction, and the Fe content in the Fe dendritic phase decreased slightly.
10.3390-met13050967	4	transformation; martensite; martensitic; phase; shape; beta; memory; shape memory; temperature; temperatures; martensitic transformation; gamma; transformation temperatures; effect; thermal	For the first time, using optical, scanning, and transmission electron microscopy and X-ray phase analysis in combination with measurements of tensile mechanical properties, we obtained data on the structural features of the polycrystalline shape-memory eutectoid Cu-Al-Ni-(B) alloys doped by aluminum (of 10 and 14 wt% Al in total amount), nickel (of 3, 4, and 4.5 wt% Ni), and boron (0.02-0.3 wt% B) in various compositions. The effect of boron on the grain sizes, structure, phase composition, and mechanical properties of shape memory (SM) alloys has been studied. The localization of aluminum borides in the structure was investigated and an effect of grain growth inhibition in the (alpha + beta) and beta Cu-Al-Ni-B alloys was established, both in the cast state of the alloys considered and after their heat treatment.
10.3390-met13071304	-1		Immiscible Cu-Fe alloys exhibit poor corrosion resistance due to different corrosion potentials between the constituent phases, which limits their application. In this paper, a composite gradient-structured Cu-10 wt%Fe plate was prepared via the ultrasonic surface rolling process (USRP). The microstructure evolution, mechanical properties and corrosion behavior were studied. The results demonstrate that USRP effectively enhances both the strength and corrosion resistance of the Cu-10Fe alloy. The improved strength is related to the combined effects of Hall-Petch strengthening, dislocation strengthening, and additional strengthening resulting from homogeneous deformation between the surface layer and the matrix. The enhanced corrosion resistance is primarily attributed to the refined microstructure of the surface layer after USRP, which facilitates the formation of a protective passivation film.
10.3390-met13091606	7	irradiation; shear; grain; ta; deformation; size; radiation; voids; nanocrystalline; simulations; similar; void; temperature; irradiated; boundaries	The effect of oscillatory shear deformation on the fatigue life, yielding transition, and flow localization in metallic glasses is investigated using molecular dynamics simulations. We study a well-annealed Cu-Zr amorphous alloy subjected to periodic shear at room temperature. We find that upon loading for hundreds of cycles at strain amplitudes just below a critical value, the potential energy at zero strain remains nearly constant and plastic events are highly localized. By contrast, at strain amplitudes above the critical point, the plastic deformation is gradually accumulated upon continued loading until the yielding transition and the formation of a shear band across the entire system. Interestingly, when the strain amplitude approaches the critical value from above, the number of cycles to failure increases as a power-law function, which is consistent with the previous results on binary Lennard-Jones glasses.
10.3390-met13111835	-1		In this investigation, Cu-Ni alloys with different aluminum additions were synthetized under a vacuum atmosphere to reduce the material density. Annealed alloys in a He atmosphere with low aluminum concentration exhibited a coarse dendritic structure, while samples with high aluminum concentration exhibited a refined dendritic structure. Structural defects analyses have shown relatively low vacancy concentrations. Hardness evaluations indicated an increment by approximately 5 times i.e., 370 HVN, more than that for the alloyed samples compared with the as-cast and unalloyed samples. Compression tests have shown a noticeable strengthening improvement (360 MPa), mainly in samples heat treated with 10 at% Al, while samples with 5 at% Al showed an acceptable resistance (270 MPa) as well. In general, the sample with 10 at% Al presented the best performance to be considered as potential structural material.
10.3390-met13121923	6	grain; deformation; strain; strength; dislocation; cu-; tensile; size; ecap; grain size; sfe; ductility; hardening; high; stress	Alloys with a gradient structure (GS) exhibit a superior combination of strength and ductility. However, the effects of treatment temperature and stacking fault energy on the tensile behavior and microstructure evolution of GS alloys have not been systematically investigated. In this study, GS Cu-Al-Zn alloys with different stacking fault energy (SFE, 40/7 mJ/m2) were prepared using surface mechanical attrition treatment (SMAT) at cryogenic and room temperature, respectively. The microstructure results indicate that more stacking faults and deformation twins were activated in the SFE-7 alloys at cryogenic temperature, which led to higher strength compared to that of the alloys SMAT-ed at room temperature. In addition, it was found that the yield strength and hetero-deformation-induced (HDI) stress of the SFE-7 alloy were significantly higher than those of the SFE-40 alloy, resulting in a good combination of strength and ductility. Furthermore, more dispersed strain bands were observed in the SFE-7 sample during whole tensile deformation, which contributes to higher ductility.
10.3390-met13121942	-1		Powder metallurgy (PM) processes for porous copper and alloys have seen some commercial successes, but PM methods have the disadvantage of relatively low porosity or strength that is compromised by stress-concentrating interparticle bonds. To increase porosity without compromising scalability, a Cu-CuO metal matrix composite powder was utilized to produce additional microscale porosity within the particles by oxide reduction. These Cu-CuO powders were pressed at 1, 2, or 3 GPa, and made porous at 600, 800, or 1000 degrees C to investigate the effects of pressing and sintering parameters on the overall strength and density. It was found that the formation of porosity is weakly dependent on compaction pressure (maximum 6% difference from 1 GPa to 3 GPa), while the final porosity varied by similar to 16% overall (similar to 40% for 1 GPa and 600 degrees C to 24% for 3 GPa and 1000 degrees C). The strength of the porous Cu was highest after being reduced at 600 degrees C but also exhibited some flaking at the edges at high strain. The 1 GPa, 600 degrees C samples have a higher specific strength than wrought Cu annealed at the same temperature, as was demonstrated under uniaxial quasi-static compression as well as split Hopkinson pressure bar impact.
10.3390-met14050552	-1		In order to design Cu-Sn alloys with excellent overall performance, the structural stability, mechanical properties, and electronic structure of X-doped Cu-Sn alloys were systematically calculated using first-principles calculations. The calculation results of the cohesive energy indicate that the Cu-Sn-X structures formed by X atoms (X = Ag, Ca, Cd, Mg, Ni, Zr) doping into Cu-Sn can stably exist. The Cu-Sn-Ni structure is the most stable, with a cohesive energy value of -3.84 eV. Doping of X atoms leads to a decrease in the bulk modulus, Possion's ratio and B/G ratio. However, doping Ag and Ni atoms can improve the shear modulus, Young's modulus, and strain energy of the dislocation. The doping of Ni has the highest enhancement on shear modulus, Young's modulus, and strain energy of the dislocation, with respective values as follows: 63.085 GPa, 163.593 GPa, and 1.689 W/Jm-1. The analysis of electronic structure results shows that the covalent bond between Cu and X is the reason for the performance differences in Cu-Sn-X structures.
10.3390-met14060620	-1		In the current work, a novel medium entropy copper alloy was designed with the aim of avoiding the use of expensive, hazardous or scarce alloying elements and instead employing widely available and cost-effective alternatives. In order to investigate this unknown region of multicomponent alloy compositions, the thermo-physical parameters were calculated and the CALPHAD method was utilized. This led to the design of the Cu50Zn25Al20Sn5 at. % (Cu53.45Zn27.49Al9.08Sn9.98 wt. %) alloy with a relatively low density of 6.86 g/cm3 compared with conventional brasses. The designed alloy was manufactured through vacuum induction melting, producing two ingots weighing 1.2 kg each, which were subjected to a series of heat treatments. The microstructural evolution of the alloy in the as-cast and heat-treated conditions was assessed through optical and scanning electron microscopy. The hardness of the as-cast and heat-treated alloy at room temperature was also studied. The alloy was characterized by a multiphase microstructure containing a major Cu-rich (Cu-Zn-Al) matrix reinforced with a secondary Zn-rich (Zn-Cu) phase and pure Sn. In terms of mechanical properties, the developed alloy exhibited high hardness values of roughly 378 HV0.2 and 499 HV0.2 in the as-cast and heat-treated conditions, respectively.
10.3390-met14060694	-1		Gradient grain structure materials with superior mechanical properties of high strength and high toughness have attracted widespread attention. Gradient materials can effectively improve toughness by constructing a microstructure from fine to coarse crystals inside the material, which has gradually become a hotspot of attention in the academic and engineering communities. In this paper, based on the crystal plasticity intrinsic theory, dislocation density is introduced as a characterization quantity, and cohesive units are added at grain boundaries to simulate damage fractures. The results of this study reveal the fracture damage mechanism of gradient crystal structure materials, providing new ideas and methods for the design of gradient materials.
10.3390-met14070831	14	strength; properties; conductivity; electrical; mechanical; cu-; grain; mpa; electrical conductivity; aging; precipitation; phase; mechanical properties; tensile; phases	The addition of alloying elements is a crucial factor in improving the mechanical properties of pure copper, particularly in terms of enhancing its yield strength and hardness. This study examines the influence of scandium additions (up to 0.27 wt%) on low-alloyed copper. Following the casting and solution-annealing processes, the alloys were quenched in water to maintain a supersaturated state. The mechanical properties were evaluated by tensile tests to measure the yield strength and the dynamic resonance method to determine the modulus of rigidity. Additionally, X-ray diffraction was utilized to analyze changes in lattice parameters, elucidating the structural modifications induced by scandium. This study dissects the parelastic and dielastic effects underlying the solid solution hardening mechanism, providing insights into how scandium alters copper's mechanical properties. The findings align with the solid solution hardening theories proposed by Fleischer and Labusch, providing a comprehensive understanding of the observed phenomena.
10.3390-met14090978	-1		Cu-Al alloys are widely used in electronics, new energy, and other fields due to the combination of th excellent corrosion resistance and electrical conductivity of Cu and the light weight of Al. In this paper, the powder metallurgy and equal-channel angular pressing compound technology was used to fabricate a Cu-Al alloy joint, which can be used to replace armor. Devices such as an optical microscope, electron scanning microscope, and microhardness scale were used to characterize the microstructure and mechanical properties of the Cu-Al alloys. The finite element analysis software Abaqus was used to analyze stress distribution during equal-channel angular pressing. The results indicated that the microstructure and properties of Cu-Al alloys were closely related to the volume ratio of Cu-Al. The microhardness and tensile strength were significantly increased by increasing the volume ratio of Cu-Al. As the volume ratio of Cu-Al varied from 1:2 to 2:1, the ultimate tensile strength of the Cu-Al alloys increased from 79.9 MPa to 164.9 MPa at room temperature and the microhardness increased from 60 HV to 101 HV. However, the elongation of the Cu-Al alloys hardly changed; this was about 4.4%. Crack initiation occurred at the Cu-Al interface and spread along the bonding surface of the Cu-Al alloys during the tensile process.
10.3390-met14090984	-1		The yielding transition, structural relaxation, and mechanical properties of metallic glasses subjected to repeated loading are examined using molecular dynamics simulations. We consider a poorly annealed Cu-Zr amorphous alloy periodically deformed in a wide range of strain amplitudes at room temperature. It is found that low-amplitude cyclic loading leads to a logarithmic decay of the potential energy, and lower energy states are attained when the strain amplitude approaches a critical point from below. Moreover, the potential energy after several thousand loading cycles is a linear function of the peak value of the stress overshoot during startup continuous shear deformation of the annealed sample. We show that the process of structural relaxation involves collective, irreversible rearrangements of groups of atoms whose spatial extent is most pronounced at the initial stage of loading and at higher strain amplitudes. At the critical amplitude, the glass becomes mechanically annealed for a number of transient cycles and then yields via the formation of a shear band. The yielding transition is clearly marked by abrupt changes in the potential energy, storage modulus, and fraction of atoms with large nonaffine displacements.
10.3390-met14091078	-1		Residual arsenic in copper matte is a source of arsenic contamination in subsequent processes in the smelting section of copper pyrometallurgy. In order to solve the impact of arsenic in copper matte on the subsequent process of smelting, this study removes arsenic from copper matte by adding an arsenic removal agent to the molten copper matte. The results show that the most difficult arsenic phase in copper matte is the residual arsenic in copper-arsenic alloys, based on which sodium carbonate was selected as the arsenic removal agent. The arsenic content in the copper matte was reduced by 98% under the optimal experimental conditions of a reaction temperature of 1250 degrees C, 4% sodium carbonate addition, and a reaction time of 60 min. The experimental results of the reaction mechanism show that sodium carbonate plays two main roles in the process of removing the intractable residual arsenic in copper matte. One is that sodium carbonate has a low melting point, which enhances the fluidity of the reactants. The other is that it can provide oxygen to the reaction system and convert arsenic in the copper-arsenic alloy into gaseous arsenic and arsenate. This study can provide new ideas for controlling arsenic pollution in copper pyrometallurgy.
10.3390-met14101100	-1		Cu-W alloys are widely used in high-voltage circuit breaker contacts due to their high resistance to arc ablation, but few studies have analyzed the microstructure of Cu-W alloys under arc ablation. This study applied a phase-field model based on the phase-field model developed by Karma and co-workers to the evolution of dendrite growth in the solidification process of Cu-W alloy under arc ablation. The process of columnar dendrite evolution during solidification was simulated, and the effect of the supercooling degree and anisotropic strength on the morphology of the dendrites during solidification was analyzed. The results show that the solid-liquid interface becomes unstable with the release of latent heat, and competitive growth between dendrites occurs with a large amount of solute discharge. In addition, when the supercooling degree is 289 K, the interface is located at a lower height of only 15 mu m, and the growth rate is slow. At high anisotropy, the side branches of the dendrites are more fully developed and tertiary dendritic arms appear, leading to a decrease in the alloy's relative density and poorer ablation resistance. In contrast, the main dendrites are more developed under high supercooling, which improves the density and ablation resistance of the material. The results in this paper may provide a novel way to study the microstructure evolution and material property changes in Cu-W alloys under the high temperature of the arc for high-voltage circuit breaker contacts.
10.3390-met14121330	-1		The influence of heat treatment and deformation on the microstructure and properties of a Cu-Ni-Si alloy/AA8030 alloy composite wire was studied. After aging at 450 degrees C for 60 min, the composite wire exhibited relatively high comprehensive properties, with ultimate tensile strength, elongation, and electrical conductivity values of 253 MPa, 11.1%, and 55.3% IACS, respectively. Microstructural analysis revealed that precipitation and dislocation strengthening played important roles in the aged Cu-Ni-Si alloy cladding, whereas grain boundary and dislocation strengthening contributed to the strength of the AA8030 alloy. Then, the wire underwent five passes of drawing with a total deformation of 75%. Significant work hardening changed the ultimate tensile strength, elongation, and electrical conductivity of the composite wire to 422 MPa, 3.3%, and 53.6% IACS, respectively. CuAl2, CuAl and Cu9Al4 layers were formed at the composite interface during aging. The CuAl2 and Cu9Al4 layers grew toward the Al alloy and Cu alloy, respectively, whereas the CuAl layer grew toward both the Al alloy and the Cu alloy.
10.3390-met14121331	-1		Commercially pure Cu features excellent electric conductivity but low mechanical properties. In order to improve the mechanical properties of Cu, strengthening elements can be added to prepare alloys or composites featuring enhanced performances. This study focuses on the detailed characterization of the microstructure of a Cu composite strengthened with Al2O3 particles during high shear strain processing. The Cu-Al2O3 mixture was prepared by powder metallurgy and directly consolidated by the intensive plastic deformation method of hot rotary swaging. Samples cut from the consolidated piece were further processed by the severe plastic deformation method of high pressure torsion (HPT). The primary aim was to investigate the effects of varying degrees of the imposed shear strain, i.e., the number of HPT revolutions, microstructure development (grain size and morphology, texture, grain misorientations, etc.) of the consolidated composite; the microstructure observations were supplemented with measurements of Vickers microhardness. The results showed that the added oxide particles effectively hindered the movement of dislocations and aggravated grain fragmentation, which also led to the relatively high presence of grain misorientations pointing to the occurrence of residual stress within the microstructure. The high shear strain imposed into (the peripheral region of) the sample subjected to four HPT revolutions imparted equiaxed ultra-fine grains and an average Vickers microhardness of more than 130 HV0.1.
10.3390-met14121360	15	aging; strength; conductivity; electrical conductivity; electrical; mpa; treatment; strengthening; degrees; cu-; cold; precipitation; tensile strength; tensile; iacs	The effects of Ti addition on the microstructure, mechanical properties and corrosion resistance of the Cu-30Zn-6Ni-1.5Ti (wt%) alloy were investigated in the present study. Microstructure analysis confirms that the Ni3Ti and NiTi phases are formed in the Cu-Zn-Ni-Ti alloy. Most of the Ni3Ti particles dissolve into the matrix, whereas NiTi particles remained after the solution treatment. Moreover, nano-sized Ni3Ti and Cu2NiZn phases are precipitated from the matrix during the aging process. The yield strength improvement of the studied alloy is attributed to the Orowan strengthening (accounting for 42.5% of the total yield strength), then the grain boundary strengthening (31.1%), the dislocation strengthening (16.9%), the twin boundary strengthening (5.0%) and the solid solution strengthening (0.5%). After cold rolling with 90% deformation and aging at 440 degrees C for 1 h, the designed alloy has a hardness of 327.1 HV, a yield strength of 1192 MPa, an ultimate tensile strength of 1297 MPa, an elongation of 1.8%, an electrical conductivity of 11.2% IACS and a corrosion rate of 2.8 mu m/month in 3.5% NaCl solution.
10.3390-met14121451	-1		The effects of medium and flow rate on the film-forming structures of B10 Cu-Ni alloys and their resistance to corrosion caused by sulfate-reducing bacteria are investigated in this article. Combined with a predicted cloud map of pipeline corrosion area and a particle motion trajectory map obtained using Computational Fluid Dynamics (CFD), the growth law of alloy passivation films was analyzed and the pitting process of sulfate-reducing bacteria (SRB) on passivation films was revealed. The results show that the film formation effect is best when the stream of water in the film-forming environment is filtered seawater with a flow rate of 0.8 m/s, which consists of a uniform and dense gray-brown passivated film layer with the strongest resistance to SRB corrosion. When the flow rate is 0 m/s, the clay particles in the seawater cover the surface of the passivation film, hindering the contact of oxygen with the substrate and inhibiting the growth of the passivation film. When the stream of water in the film-forming environment is seawater with a flow rate of 3 m/s, the surface of the substrate shows obvious scouring marks, which is favorable for the enrichment of SRB and further accelerates the pitting corrosion of the substrate. Cl- has a significant influence on the formation of passivation films on B10 Cu-Ni alloys. When the filming medium is deionized water, the B10 Cu-Ni alloy does not form a complete passivation film at all flow rates.
10.3390-met15020216	5	materials; thermal; heat; properties; material; welding; sintering; fusion; strength; laser; heat sink; thermal conductivity; mechanical; sink; manufacturing	Copper alloys are widely used in many branches of industry due to their excellent corrosion resistance and high level of both electrical conductivity and strength . Among others, there are copper alloys with magnesium, which are known and commonly used with Mg content of up to 0.7 wt%. Here, we study Cu-Mg alloys with 2.8 wt% and 3.2 wt% of Mg, the properties of which are yet to be determined. One of these is the fatigue strength of materials, which is crucial for maintaining the long-term and safe operation of wires in engineering applications. Fatigue is a process during which materials are subjected to cyclic stress below the ultimate tensile strength of materials, leading to their damage or failure. In the current paper, CuMg2.8 and CuMg3.2 wires were obtained using a laboratory chain drawbench and an industrial drum-type drawing machine to verify the influence of manufacturing technology on the fatigue strength of materials. The obtained results were correlated with analogically obtained copper wires by taking into consideration the influence of the chemical composition, structure of fractures, stress and manufacturing technology. It was discovered that it is possible to obtain wires regardless of the drawing machine type and the concentration of Mg. However, CuMg3.2 wires obtained in the industrial conditions experienced delamination and brittle fractures during unwinding from the drum, and thus, their use was not possible.
10.3390-met15040368	-1		Cu-based alloys and composites are popular to prepare electroconductive parts. However, their processing can be challenging, especially in case of composites strengthened with oxides. To save the necessary time and costs, numerical simulations can be of help when determining the deformation behaviour of (newly introduced) materials. The study presents a combined method of strengthening of Cu by adding 5 wt% of La2O3 particles and performing shear-based deformation by equal channel angular pressing (ECAP). The effects of the method on the microstructure, mechanical properties, and thermal stability of the composite are examined both numerically and experimentally. The results showed that the La2O3 addition caused the maximum imposed strain to be higher for the composite than for commercially pure Cu, which led to the development of subgrains and shear bands within the microstructure, and a consequent increase in microhardness. The numerical predictions revealed that the observed differences could be explained by the differences in the material plastic flow (comparing the composite to commercially pure Cu). The work hardening supported by the addition of La2O3 led to a significant increase in stress and punch load during processing, as well as contributed to a slight increase in deformation temperature in the main deformation zone of the ECAP die. Certain inhomogeneity of the parameters of interest across the processed workpiece was observed. Nevertheless, such inhomogeneity is typical for the ECAP process and steps prospectively leading to its elimination are proposed.
10.3390-met15060641	-1		In response to the performance requirements of ship conductive rings in the coupled environment of high salt spray, high humidity, and mechanical wear in the ocean, a Cu-TiC composite coating was prepared on the surface of 7075 aluminum alloy by using the high-speed laser cladding (HLC) technology. The influence laws of the scanning speed (86.4-149.7 mm/s) on the microstructure, tribological properties, and corrosion resistance of the coating were explored. The results show that the scanning speed significantly changes the phase composition and grain morphology of the coating by regulating the thermodynamic behavior of the molten pool. At a low scanning speed (86.4 mm/s), the CuAl2 phase is dominant, and the grains are mainly columnar crystals. As the scanning speed increases to 149.7 mm/s, the accelerated cooling rate promotes an increase in the proportion of Cu2Al3 phase, refines the grains to a coexisting structure of equiaxed crystals and cellular crystals, and improves the uniformity of TiC particle distribution. Tribological property analysis shows that the high scanning speed (149.7 mm/s) coating has a 17.9% lower wear rate than the substrate due to grain refinement and TiC interface strengthening. The wear mechanism is mainly abrasive wear and adhesive wear, accompanied by slight oxidative wear. Electrochemical tests show that the corrosion current density of the high-speed cladding coating is as low as 7.36 x 10-7 Acm-2, and the polarization resistance reaches 23,813 Omegacm2. The improvement in corrosion resistance is attributed to the formation of a dense passivation film and the blocking of the Cl diffusion path . The coating with a scanning speed of 149.7 mm/s exhibits optimal wear-resistant and corrosion-resistant synergistic performance and is suitable for the surface strengthening of conductive rings in extreme marine environments. This research provides theoretical support for the process performance regulation and engineering application of copper-based composite coatings.
10.3390-met15070688	-1		Cu-5wt%TiC coatings were fabricated by high-speed laser cladding on the 7075 aluminum alloy substrate using various scanning speeds to improve its current-carrying wear resistance. The effects of scanning speed on the microstructure, phase, hardness, and current-carrying tribological properties of the coating were investigated using a scanning electron microscope, an X-ray diffractometer, a hardness tester, and a wear tester, respectively. The results show that the increase in scanning speed accelerates the coating's solidification rate. Among the samples, the coating comprised of equiaxed crystals prepared at 149.7 mm/s presents the best quality, but solidification speeds that are too rapid lead to elemental segregation. The hardness of the coating also decreases with the increase in scanning speed. The coating prepared at 149.7 mm/s exhibits the best wear resistance and electrical conductivity. The wear rate of the coating prepared at 149.7 mm/s at 25 A was 4 x 10-3 mgm-1, respectively. During the current-carrying friction process, the presence of thermal effects and arc erosion cause the worn track to be prone to oxidation, adhesion, and plastic deformation, so the current-carrying wear mechanisms of coatings at 25 A include adhesive wear, oxidation wear, and electrical damage.
10.3390-met15070735	-1		Cr alloyed Cu exhibits puzzlingly high electrical conductivity compared with other 3d elements alloying. Here, we present a theoretical understanding based on standard electronic band structure calculations. The influence of local spin-polarization on electrical conductivity was first investigated. It is found that the non-magnetic calculation produces a high density of states peak at the Fermi level, and then it fails to explain the high electrical conductivity of Cu-Cr alloy. When spin polarization is taken into account, the density of states is significantly reduced, and the results are in good agreement with experimental measurements. Meanwhile, the calculation results can explain the increase in strength and also lead to some interesting deductions. Finally, a computational program is proposed to select a high electrical conductivity Cu alloy based on a simple calculation model.
10.3390-met15091023	2	corrosion; surface; film; electrochemical; films; spectroscopy; layer; current; solution; potential; resistance; composition; x-ray; ions; showed	In this study, the properties of Cu(Co) alloy films were investigated to assess their utility as an alternative material for interconnections in hybrid bonding applications. Thin films of Cu(Co) were deposited using electrochemical deposition in a standard sulfate-based electrolyte. X-ray photoelectron spectroscopy (XPS) of the films revealed that an increasing current density during deposition resulted in an increase in cobalt concentration. Bright-field scanning transmission electron microscopy (STEM) coupled with energy-dispersive x-ray spectroscopy (EDS) was used to visualize the fine-grained microstructure and confirmed grain boundary segregation of cobalt in the films. X-ray diffraction with a heated stage determined that the coefficient of thermal expansion (CTE) increased linearly with increasing cobalt content, from 17.5 ppm/K for pure copper to a maximum of 27.5 ppm/K for a film containing 24 at% Co. Nanoindentation experiments found that the mechanical properties depended non-linearly on composition, with hardness increasing from 3.5 GPa for a 0% cobalt film to a maximum of 4.5 GPa (24 at% Co) and the Young's modulus increasing from 118 GPa to 214 GPa, respectively. Four-point probe electrical measurements confirmed the expected linear increase in resistivity as Co content increased. Since electrical and mechanical properties have differing dependences on the film composition, an optimal alloy composition that balances an acceptable increase in resistance with improved mechanical properties could enable more reliable, low-temperature bonding solutions in advanced microelectronic devices.
10.3390-met5020763	-1		There is an increasing demand in the industry for conductive high strength copper alloys. Traditionally, alloy systems capable of precipitation hardening have been the first choice for electromechanical connector materials. Recently, ultrafine-grained materials have gained enormous attention in the materials science community as well as in first industrial applications (see, for instance, proceedings of NANO SPD conferences). In this study the potential of precipitation hardened ultra-fine grained copper alloys is outlined and discussed. For this purpose, swaging or accumulative roll-bonding is applied to typical precipitation hardened high-strength copper alloys such as Corson alloys. A detailed description of the microstructure is given by means of EBSD, Electron Channeling Imaging (ECCI) methods and consequences for mechanical properties (tensile strength as well as fatigue) and electrical conductivity are discussed. Finally the role of precipitates for thermal stability is investigated and promising concepts (e.g. tailoring of stacking fault energy for grain size reduction) and alloy systems for the future are proposed and discussed. The relation between electrical conductivity and strength is reported.
10.3390-met6090225	-1		In recent years, CuZr-based bulk metallic glass (BMG) composites ductilized by a shape memory B2 CuZr phase have attracted great attention owing to their outstanding mechanical properties. However, the B2 CuZr phase for most CuZr-based glass-forming compositions is only stable at very high temperatures, leading to the uncontrollable formation of B2 crystals during quenching. In this work, by introducing Co (i.e., 4, 5, and 6 at. %) and 10 at. % Al into CuZr-based alloys, the relatively good glass-forming ability (GFA) of CuZr-based alloys still can be achieved. Meanwhile, the B2 phase can be successfully stabilized to lower temperatures than the final temperatures of crystallization upon heating CuZr-based BMGs. Unlike previous reported CuZr-based BMGs, the primary crystallization products upon heating are mainly B2 CuZr crystals but not CuZr2 and Cu10Zr7 crystals. Furthermore, the primary precipitates during solidification are still dominated by B2 crystals, whose percolation threshold is detected to lie between 10 +/- 2 vol. % and 31 +/- 2 vol. %. The crystallization kinetics underlying the precipitation of B2 crystals was also investigated. Our results show that the present glass-forming composites are promising candidates for the fabrication of ductile CuZr-based BMG composites.
10.3390-met7040141	-1		The columnar-grained Cu71.5Al17.5Mn11 shape memory alloy was treated by single-pass hot rolling at 900 degrees C with a thickness reduction of 67.3% followed by immediate water quenching. Dynamic recovery other than discontinuous dynamic recrystallization occurred during the treatment process, bringing about retained columnar grains with <001> textures, as well as dislocations introduced into the parent matrix. As a result, a large maximum recoverable strain of more than 11% was maintained due to the retained beneficial grain characteristics. The critical stress for inducing martensitic transformation and stress hysteresis were enhanced mainly due to the existence of dislocations.
10.3390-met7040148	-1		Cu60Zr30Ti10 metallic glass powder was prepared by mechanically alloying a mixture of pure Cu, Zr, and Ti powders after 5 h of milling. Cu60Zr30Ti10 bulk metallic glass (BMG) was synthesized by vacuum hot pressing the as-milled Cu60Zr30Ti10 metallic glass powder at 746 K in the pressure range of 0.72-1.20 GPa, and the structure was analyzed through X-ray diffraction and transmission electron microscopy. The pressure could enhance the thermal stability, and prolong the existence, of the amorphous phase inside the Cu60Zr30Ti10 powder. Furthermore, the corrosion behavior of the Cu-based BMG in four corrosive media was studied using a potentiodynamic method. The Cu60Zr30Ti10 BMG exhibited a low corrosion rate and current density in 1 N solutions of H2SO4, NaOH, and HNO3. X-ray photoelectron spectroscopy results revealed that the formation of Zr- and Ti-rich passive oxide layers provides a high corrosion resistance against 1 N H2SO4 and HNO3 solutions, and the breakdown of the protective film by Cl- attack was responsible for pitting corrosion in a 3 wt% NaCl solution. The formation of oxide films and the nucleation and growth of pitting were analyzed through microstructural investigations.
10.3390-met7090383	-1		Grain refinement by elemental addition has been extensively investigated within the last decades in Al or Mg alloys. In contrast, in the Cu system, the role of solute on grain size is less investigated. In this study, the grain refinement potency of several alloying elements of the Cu system was examined. To predict grain size depending on the growth restriction factor Q, grain size modelling was performed. The results obtained by the grain size model were compared to variations in the grain size of binary Cu alloys with increasing solute content under defined cooling conditions of the TP-1 grain refiner test of the Aluminium Association (c). It was found that the experimental results differed significantly from the predicted grain size values for several alloying elements. A decreasing grain size with increasing alloy concentration was observed independently of the growth restriction potency of the alloying elements. Furthermore, excessive grain coarsening was found for several solutes beyond a transition point. It is assumed that contradictory variations in grain size result from a change in the nucleating particle density of the melt. Significant decreases in grain size are supposed to be due to the in-situ formation of potent nucleation sites. Excessive grain coarsening with increasing solute content may occur due to the removal of nucleating particles. The model shows that the difference in the actual number of particles before and beyond the transition point must be in the range of several orders of magnitude.
10.3390-met7100397	1	shape; memory; shape memory; damping; martensite; martensitic; damping capacity; transformation; capacity; strain; superelasticity; temperature; cu-al-mn; shape memory effect; effect	Damping properties of the inherent and intrinsic internal friction peaks (IFPT + IFI) of Cu-xZn-11Al (x = 7.0, 7.5, 8.0, 8.5, and 9.0 wt. %) shape memory alloys (SMAs) were investigated by using dynamic mechanical analysis. The Cu-7.5Zn-11Al, Cu-8.0Zn-11Al, and Cu-8.5Zn-11Al SMAs with (IFPT + IFI)(beta 3(L21)->gamma 3' (2H)) peaks exhibit higher damping capacity than the Cu-7.0Zn-11Al SMA with a (IFPT + IFI)(beta 3(L21)->gamma 3' (2H)) peak, because the gamma(3)' martensite phase possesses a 2H type structure with abundant movable twin boundaries, while the beta(3)' phase possesses an 18R structure with stacking faults. The Cu-9.0Zn-11Al SMA also possesses a (IFPT + IFI)(beta 3(L21)->gamma 3' (2H)) peak but exhibits low damping capacity because the formation of gamma phase precipitates inhibits martensitic transformation. The Cu-8.0Zn-11Al SMA was found to be a promising candidate for practical high-damping applications because of its high (IFPT + IFI) peak with tan delta > 0.05 around room temperature.
10.3390-met8040227	-1		In this paper, the precipitation, recrystallization, and evolution of twins in Cu-Cr-Zr alloy strips were investigated. Tensile specimens were aged at three different temperatures for various times so as to bring the strips into every possible aging condition. The results show that the appropriate aging parameter for the 70% reduced cold-rolled alloy strips is 723 K for 240 min, with a tensile strength of 536 MPa and an electrical conductivity of 85.3% International Annealed Copper Standards (IACS) at the peak aged condition. The formation of fcc (face-centered cubic) ordered Cr-rich precipitates (beta) is an important factor influencing the significant improvement of properties near the peak aged condition. In terms of crystallographic orientation relationships, there are basically two types of beta' precipitates in the alloy. Beyond the Cr-rich precipitates (beta'(I)) formed during the early aging stages, which mimic a cube-on-cube orientation relationship (OR) with the matrix, another Cr-rich precipitate (beta'(II)) is observed in the peak aged condition. p i (II) is coherent with the matrix, with the following ORs: [111](beta'(II)) //[100](Cu), {02-2}(beta'(II))//[02-2](Cu) and [011](beta'(II))//(II)[211](Cu), {200}(beta'(II)) //{1-1111}(cu) . These precipitates have a strong dislocation and grain boundary pinning effect, which hinder the dislocation movement and crystal boundary migration, and eventually delay recrystallization and enhance the recrystallization resistance of the peak aged strips. During the subsequent annealing process, the transition phase beta' gradually loses the coherence mismatch and grows into a larger equilibrium phase of chromium with a bcc (body-centered cubic) structure (beta), resulting in the reduction of the pinning effect to dislocations and sub-grains, so that recrystallization occurs. Annealing twins are formed during the recrystallization process to release the deformation energy and to reduce the drive force for interface migration, eventually hindering grain growth .
10.3390-met8060444	-1		As material for key parts applied in the aerospace field, the Cu-Be-Co-Ni alloy sustains cyclic plastic deformation in service, resulting in the low cycle fatigue (LCF) failure. The LCF behaviors are closely related to the precipitation states of the alloy, but the specific relevance is still unknown. To provide reasonable regulation of the LCF properties for various service conditions, the effect of precipitation states on the LCF behaviors of the alloy was investigated. It is found that the alloy composed fully of non-shearable gamma' precipitates has higher fatigue crack initiation resistance, resulting in a longer fatigue life under LCF process with low total strain amplitude. The alloy with fine shearable gamma'(I) precipitates presents higher fatigue crack propagation resistance, leading to a longer fatigue life under LCF process with high total strain amplitude. The cyclic stress response behavior of the alloy depends on the competition between the kinematic hardening and isotropic softening. The fine shearable gamma'(I) precipitates retard the decrease of effective stress during cyclic loading, causing cyclic hardening of the alloy. The present work would help to design reasonable precipitation states of the alloy for various cyclic loading conditions to guarantee its safety in service.
10.3390-met8060455	-1		The effect of temperature, soaking time and particle size on the dissolution of particles (Fe3P and Fe) during homogenization was simulated employing Thermocalc (R) and DICTRA software. The initial precipitate size was determined through metallographic evaluation on industrial as-cast Cu-Fe-P alloy. The particle sizes vary from submicron (< 1 mu m) up to 10 mu m before the heat treatment. As homogenization temperature rises, the dissolution rate increases as well, but only on temperatures above 1273 K (1000 degrees C) is the rate capable of completely dissolving particles effectively. At temperatures above 1273 K (1000 degrees C), precipitates with sizes below 5 mu m dissolve completely into the Cu matrix, while larger particles only slightly decrease their size. Particles at enriched copper areas remain undissolved and slightly increase their size which is attributed to micro segregation and the local change of equilibrium conditions. The simulation results are in agreement with homogenization trials at lab scale.
10.3390-met8070537	-1		The densification mechanism of Cu-Al mixed metal powder during a double-action die compaction was investigated by numerical simulation. The finite element method and experiment were performed to compare the effect of the forming method, such as single-action die compaction and double-action die compaction, on the properties of compact. The results showed that the latter could significantly raise the densification rate and were in good agreement with Van Der Zwan-Siskens compaction equation. The effects of the different initial packing structures on the properties of the compact were studied. The results showed that a high-performance compact could be obtained using a dense initial packing structure at a given compaction pressure. Additionally, the effects of the Al content and compaction pressure on the relative density and stress distribution were analyzed. It was observed that, with an increase in the Al content at a given compaction pressure, the relative density of the compact increased, whereas the stress decreased. Furthermore, when the Al content was fixed, the relative density and stress increased with increasing compaction pressure. The relationship between the relative density and the compaction pressure under different friction conditions was characterized and fitted according to the Van Der Zwan-Siskens compaction equation. The influence mechanisms of die wall friction on the compaction behavior were investigated. It was revealed that friction is a key factor that causes the inhomogeneity of the powder flow and stress distribution. Finally, the effects of the dwell time and height-diameter ratio on the densification behavior were analyzed, and it was found that an increase in the dwell time promoted the densification process, whereas an increase of the height-diameter ratio could hinder the process.
10.3390-met8080571	0	solidification; phase; magnetic; magnetic field; undercooling; field; liquid; separation; peritectic; immiscible; cu-; dendrite; phase separation; microstructure; primary	An alternating magnetic field (AMF) was applied during the solidification process of the Cu-14Fe alloy and the effect of the electromagnetic parameter, which impact the model and solidification technique of the solidification structure that were analyzed. Results show that an AMF applied during the solidification process significantly reduced macro-segregation and gas hole defects. During the growth process of the primary Fe phase, the AMF impacted the nucleation of detached grains and fusing dendrites. Specifically, the developed Fe dendrites were transformed to rosettes or spherical grains in the presence of an applied AMF while the grain distribution was more disperse and uniform. It was found that the growth behavior of Fe grains under AMF depended upon the combined effects of the electromagnetic force and electromagnetic heat.
10.3390-met8090722	-1		In the present work, Cu-Pb-Sn and Q235 laminated composite were fabricated by a horizontal semisolid rolling procedure. The interfacial structure, elemental distribution, and properties of the composite were investigated. Finite-element simulation was conducted to analyze the temperature field and solidification process during the semisolid rolling. An appropriate semi-solid region was observed at a pouring temperature of 1598 K in the simulation, which would effectively kept fluidity and avoided casting defects. The experimental results showed that good interface between Cu-Pb-Sn alloy and Q235 steel was achieved by the proposed process at 1598 K, without casting defects or excessive deformation. The Cu and Fe alloys were bonded mainly by the diffusion of Fe into Cu matrix, and a handful of microscopic Pb-rich layer. Fine Pb-rich precipitates were uniformly distributed in the Cu-Pb-Sn alloy, and were considered to be advantageous to the self-lubrication property. The average tensile-shear strength of the interface was higher than 57.68 MPa at a pouring temperature of 1598 K, which fulfilled the requirements for a further extrusion process.
10.3390-met8100752	-1		The effect of bonding temperature on crack occurrences in alpha-Al2O3/SS 430 joints using Cu-based brazing alloys was investigated with emphasis on the microstructural characterization, hardness, and analytical residual stresses of the joints. The brazing was conducted using Cu-7Al-xTi and Cu-7Al-xZr (x = 2.5, 3.5, and 4.5) alloys at 1000 degrees C and 1080 degrees C leading to solid-liquid and liquid-state bonding, respectively. Cracks occurred in the joints brazed at 1080 degrees C irrespective of the alloys, while crack-free joints were obtained at 1000 degrees C for joints with only Cu-7Al-xZr alloys. Increases in the bonding temperature or utilization of Cu-7Al-xTi alloys led to a formation of brittle Fe-containing intermetallic or Fe-Cr phases in the brazed seams due to the dissolution of Fe from SS 430, which deteriorated the mechanical properties of the brazed seam. Maximum residual stresses of the real brazed joint were obtained by combining the calculated yield strength and measured hardness of the brazed seams. Eventually, when the hardness of the brazed seam was less than 107 HV, the yield strength was 124 MPa or less and the maximum residual stress generated in the joint corresponded to 624 MPa or less, leading to a crack-free joint.
10.3390-met8100765	2	corrosion; surface; film; electrochemical; films; spectroscopy; layer; current; solution; potential; resistance; composition; x-ray; ions; showed	Surface nano-crystallization (SNC) of a conform-extruded Cu-0.4 wt% Mg alloy was successfully conducted by high-speed rotating wire-brushing to obtain the deformed zone with dislocation cells and nanocrystallines. SNC promotes the anodic dissolution and corrosion rate of the Cu-Mg alloy in the initial stage of immersion corrosion in 0.1 M NaCl solution. The weakened corrosion resistance is mainly attributed to the higher corrosion activity of SNC-treated alloy. With extending the immersion time, the SNC-treated alloy slows the corrosion rate dramatically and exhibits uniform dissolution of the surface. The formation of the dense corrosion products leads to the improvement of overall corrosion performance. It indicates that the SNC-treated Cu-Mg alloy can function reliably for a longer duration in a corrosive environment.
10.3390-met8110869	0	solidification; phase; magnetic; magnetic field; undercooling; field; liquid; separation; peritectic; immiscible; cu-; dendrite; phase separation; microstructure; primary	Cu-15%Co alloys have been synthesized by an induction furnace adopting electromagnetic stirring (EMS). The liquid-liquid separation behavior and the peritectic reaction under a forced melt flow were analyzed. The specimens were subjected to a conventional induction melting as well as enhanced melt stirring by a two-side electromagnetic stirrer. The stirred ingots showed a significant improvement in dispersivity and homogeneity of the Co-rich phase. Comparing the specimens subjected to different current intensities, we observed strong changes in the phase fraction, the degree of segregation, and the grain size. EMS had an effect of reducing the amount and size of Co-rich droplets and enhancing the amounts of small equiaxed dendrites and dendrite fragments, which led to a more dispersive distribution of alpha-Co phase and refined the grains of Cu-rich phase. We observed a considerable increase in the fraction of peritectic Cu-rich phase with increasing current intensity of EMS, indicating that the peritectic reaction was promoted by EMS. EMS also reduced the macrosegregation of Co-rich phase in both the vertical and radial direction of the ingot when the current intensity was appropriate.
10.3390-met8110881	-1		In this work, the effects of an addition of trace alloying elements, Fe and Cr, on the mechanical and electrical properties and corrosion resistance of Cu-3Ti alloy foils, have been investigated. The results showed that the individual addition of Fe leads to the formation of Fe2Ti intermetallic phase, which refines the grain size, in the solution-treated condition. With a combined addition of Fe and Cr, the formation of the (FeCr)(2)Ti phase and the precipitation of the beta'-Cu4Ti phase resulted in increased hardness in the peak-aged condition. The ultimate tensile strength and yield strength of the peak-aged Cu-Ti-Fe-Cr alloy were 13% and 5.7% higher, than those of the Cu-3Ti alloy, respectively. The electrical conductivity of the peak-aged Cu-Ti-Fe-Cr alloy was 3.3% higher than that of the Cu-Ti-Fe alloy, due to the finer (FeCr)(2)Ti phase and the less residual Ti atoms, in the Cu matrix. The combined addition of Fe and Cr elements could improve the corrosion resistance of the Cu-Ti alloy. The Cu-Ti-Fe-Cr alloy foil could obtain the best integrated properties, and the hardness, ultimate tensile strength, and electrical conductivity were 357.1 HV, 1068 MPa and 12.5% IACS, respectively.
10.3390-met8110888	-1		In this paper, the static and fatigue properties of a Cu-Ni-Sn alloy are investigated. Tensile tests, hardness tests and microstructural analyses using optical and scanning electron microscopy (SEM) were performed and two sets of fatigue tests, with load ratio (R) R= -1 and R= 0, respectively, were carried out. The results showed the capability of the alloy to bear high static stress, thanks to its good strength properties. However, the fatigue tests showed a strong sensitivity of the alloy fatigue properties depending on the raw material batch . The comparison between microstructural analyses and fatigue test results showed a strong correlation; in particular, the specimens having a more inhomogeneous microstructure showed lower durability. In addition, the different microstructure also affected the fracture surface morphology as highlighted by SEM analyses.
10.3390-met8110919	-1		The chemical dealloying of Cu-Mg-Ca alloys in free corrosion conditions was investigated for different alloy compositions and different leaching solutions. For some of the precursor alloys, a continuous, pure fcc copper with nanoporous structure can be obtained by dealloying in 0.04 M H2SO4 solution. Superficial nanoporous copper structures with extremely fine porous size were also obtained by dealloying in pure water and 0.1 M NaOH solutions. The dealloying of both amorphous and partially crystalline alloys was investigated obtaining bi-phase nanoporous/crystal composites with microstructures depending on the precursor alloy state. The fast dissolution of Mg and Ca makes the Cu-Mg-Ca system an ideal candidate for obtaining nanoporous copper structures with different properties as a function of different factors such as the alloy composition, the quenching process, and leaching conditions.
10.3390-met8120984	-1		In order to improve the tribological performance of the slanted guide pillar, Cu particle reinforced composite coatings were synthesized on the surface of GCr15 steel using the plasma transferred arc (PTA) alloying technique. A systematic experimental investigation was conducted to study the effects of PTA current on the microstructure and microhardness of alloyed coatings. In addition, tribological behaviors at room temperature (RT) and high temperature (HT) were investigated. The results indicate that at low PTA current (70A), due to the insufficient current, no Cu particles are dissolved in the alloyed coating and a Cu-rich layer is observed on the surface. With the increase in the PTA current, Cu particles are gradually dissolved into the alloyed layer and the microstructure of alloyed coating mainly consists of bamboo-like martensite, retained austenite, and dispersed Cu particles. The microhardness of the PTA samples is approximately four times that of the untreated sample. The tribological results exhibit that an abrasive wear at RT and slight abrasive wear with oxidation wear at HT are the dominant wear mechanisms of alloyed coatings. The PTA samples show far superior antifriction properties compared to the untreated and remolten samples at both RT and HT, which can be attributed to the formation of lubricating Cu films and the improvement in microhardness.
10.3390-met9020151	6	grain; deformation; strain; strength; dislocation; cu-; tensile; size; ecap; grain size; sfe; ductility; hardening; high; stress	The work-hardening behavior of Cu-Ni alloys with high stacking-fault energies (SFEs) is experimentally investigated under uniaxial compression. It is found that, with the increase of Ni content (or short-range clustering, SRC), the flow stress of Cu-Ni alloys is significantly increased, which is mainly attributed to an enhanced contribution of work-hardening. An unexpected multistage (including Stages A, B, and C) work-hardening process was found in this alloy, and such a work-hardening behavior is essentially related to the existence of SRC structures in alloys. Specifically, during deformation in Stage B (within the strain range of 0.04-0.07), the forming tendency to planar-slip dislocation structures becomes enhanced with an increase of SRC content (namely, increase of Ni content), leading to the occurrence of work-hardening rate recovery in the Cu-20at% Ni alloy. In short, increasing SRC in the Cu-Ni alloy can trigger an unexpected multistage work-hardening process, and thus improve its work-hardening capacity.
10.3390-met9040444	-1		In this paper, an experimental investigation, based on force special parameters, is adopted to analyze the relationship between the milling tool and adhesive phenomena in milling C17200. Generally speaking, the adhesive characteristics, force fluctuations, and tool failure are the main factors affecting the impact of the cutting process on tool wear patterns. However, difficult-to-cut materials, such as the beryllium-copper alloy C17200, require machining processes with tools with lives that are difficult to predict, due to their excellent mechanical properties. To analyze the tool failure process, a series of experiments based on cutting speed and tool geometry are presented in this paper to observe the adhesive effect on tool flank surfaces and force fluctuations. The results show that the variation of special force parameters in different directions reveals that the thermal-mechanical effect on sticking substances reached a possible peak value, with inflection points in different parameters at 200 m/min. The sticking substances and tool surfaces (observed by energy disperse spectroscopy and scanning electron microscope), wear capacity, and back-scattered electron imaging also confirmed that adhesion in the wear zone reached a peak value at 200 m/min in the cutting process, exacerbating the adhesive effect on tool failure.
10.3390-met9050585	-1		The microstructure of hypereutectic immiscible Cu-50Cr alloy (wt%) was effectively refined and homogenized by a high power density Nd:YAG continuous laser beam (power density 10(4)-10(5) MW/m(2)). The average grain size of Cr was effectively refined from similar to 100 mu m to similar to 1 mu m, and some of the Cr particles even decreased to a few hundred nanometers. The high cooling rate (7.29 x 10(6) K/s) effectively inhibited the coarsening effect on Cr particles during liquid phase separation (LPS). The spherical Cr particles were preferably dispersed in the melt layer, and the thickness of the layer was up to similar to 150 mu m. The refinement and dispersion of the Cr phase contributed to improving the interruption capability of the Cu-Cr contacts. Compared with the untreated samples, the arc duration and the withstanding voltage of the laser surface melting (LSM) treated contacts with refined microstructure increased to 21% and 33%, respectively. The results demonstrated that the LSM method was an effective approach to optimize the microstructure of Cu-Cr alloy, which made it a promising modification method for Cu-Cr vacuum contact applications.
10.3390-met9060679	15	aging; strength; conductivity; electrical conductivity; electrical; mpa; treatment; strengthening; degrees; cu-; cold; precipitation; tensile strength; tensile; iacs	To obtain high strength and high electrical conductivity at the same time, the microstructure and properties of 0.2 wt% V-added, 0.1 wt% V-added and V-free Cu-1.6Ni-1.2Co-0.65Si(-V) alloys were investigated. We examined with electrical conductivity and hardness measurements, tensile test, optical microscope and transmission electron microscope (TEM). The results show that Cu-1.6Ni-1.2Co-0.65Si-0.1V alloy obtains excellent combination properties: electrical conductivity is 46.12% IACS, hardness is 293.88 HV, and tensile strength is 782 MPa, which are produced by 65% cold rolling + aging at 500 degrees C for 480 min. The addition of vanadium (V) can accelerate the precipitation of solute atoms from the copper matrix, improve the hardness and electrical conductivity of Cu-1.6Ni-1.2Co-0.65Si alloys, and greatly accelerated the aging response. delta-(Co,Ni)(2)Si and beta -Ni3Si phases are detected in Cu-1.6Ni-1.2Co-0.65Si-0.1V alloy. The Orowan mechanism and grain boundary strengthening play a major role in the yield strength strengthening due to delta-(Co,Ni)(2)Si phase.
10.3390-met9080824	-1		The microstructure evolution and stress corrosion cracking (SCC) behaviors of ultrafine-grained (UFG) Cu-Cr-Zr alloys processed by equal-channel angular pressing (ECAP) and coarse-grain (CG) Cu-Cr-Zr alloys within NaNO2 solution were systematically investigated in the current study. After deformation by eight ECAP passes, the grain size was refined to similar to 200 nm. The slow strain rate tensile (SSRT) tests showed that the ultimate tensile strength (UTS) of CG samples in solution was slightly lower than that in the air, and the elongation was decreased from 57.3% to 52.6%. In contrast, both the UTS and elongation of UFG samples in air and solution were almost identical. In NaNO2 solution, the CG fracture surface showed an obvious dissolution, microvoids, and minor cracks, while the surface of the UFG fracture was relatively smooth . The resistance of UFG samples to SCC could be significantly enhanced compared with CG samples. The grain boundary volume fraction of UFG alloy was dramatically increased, which reduced the formation of pitting corrosion. In addition, the uniform distribution of Cr particles also improved the corrosion resistance of UFG alloys.
10.3390-met9090971	-1		In this study, the Cu-Te alloy ribbons containing nanocrystalline structures were prepared by melt spinning (MS), and were composed of Cu2-x ,Te, Cu2Te, Cu3-xTe, and CuTe phases. Crystal grains on both sides of the ribbons were uniformly distributed and the grain size of the contact surface was about 400 nm. The Cu-Te powder was incorporated into the Cu2SnSe3 powder by the ball milling process and the Cu-Te/Cu2SnSe3 thermoelectric composite was prepared by spark plasma sintering (SPS). With the amount of Cu-Te powder increasing, the carrier concentration of the Cu-Te/Cu2SnSe3 composite increased, while the carrier mobility and electrical conductivity initially increased and then decreased. Compared to the Seebeck coefficient of the Cu2SnSe3 matrix, the Seebeck coefficient of the Cu-Te/Cu2SnSe3 samples increased slightly. Moreover, the Cu-Te/Cu2SnSe3 composites had lower thermal conductivity and lattice thermal conductivity over the whole temperature range. The lattice thermal conductivity of the 0.8 vol.% Cu-Te/Cu2SnSe3 composite achieved the lowest value of 0.22 W/m.K, which was 78% lower than that of the Cu2SnSe3 matrix. The maximum figure of merit of the 0.8 vol.% Cu-Te/Cu2SnSe3 composite was 0.45 at 700 K.
10.3390-mi10090573	17	wear; composites; coating; friction; composite; coatings; surface; tribological; properties; wear resistance; resistance; powder; sliding; matrix; wear rate	The surface generation mechanism of the Cu alloys in ultra-precision diamond turning is investigated by both simulation and experimental methods, where the effects of the cutting parameters on the surface characteristics are explored, including the workpiece spindle speed, the cutting depth, the feed rate and the nose radius of the diamond tool. To verify the built model, the cutting experiments are conducted at selected parameters, where the causes of the error between the simulation and the machining results are analyzed, including the effects of the materials microstructure and the diamond tool wear. In addition, the nanometric surface characteristics of the Cu alloys after the diamond turning are identified, including the finer scratching grooves caused by the tool wear, the formation of the surface burs and the adhesion of graphite. The results show that the built model can be basically used to predict the surface topography for the selection of the appropriate machining parameters in the ultra-precision diamond turning process.
10.3390-mi13020212	-1		Laser additive manufacturing is an advanced material preparation technology, which has been widely used to prepare various materials, such as polymers, metals, ceramics and composites. Zirconium diboride (ZrB2) reinforced copper composite material was fabricated using laser direct energy deposition technology. The microstructure and phase composition of the composite material were analyzed, and the influence of laser energy density on the microstructure and mechanical properties of composite materials was discussed. The results showed that the needle-like ZrB2 ceramic reinforcement was successfully synthesized via an in-situ synthesis reaction. The composites were mainly composed of needle-like ZrB2, Ni dendrites and a Cu matrix. The morphological changes of Ni dendrites could be observed at the interface inside the composite material: cellular crystals -> large-sized columnar dendrites -> small-sized dendrites (along the solidification direction). The continuous Ni dendritic network connected the ZrB2 reinforcements together, which significantly improved the mechanical properties of the composite material. At a laser energy density of 0.20 kJ/mm(2), the average microhardness of the composite material reached 294 HV0.2 and the highest tensile strength was 535 MPa. With the laser energy density increased to 0.27 kJ/mm(2), the hardness and tensile strength decreased and the elongation of the Cu composites increased due to an increase in the size of the ZrB2 and a decrease in the continuity of the Ni dendritic.
10.3390-mi14081635	-1		The effects of various drawing parameters and annealing processes on the structure and properties of Cu-Ag wires, containing 1 wt% silver, were investigated using specialized equipment including fine wire-drawing machines, very fine wire-drawing machines, heat treatment equipment, tensile testing machines, microcomputer-controlled electronic universal testers, resistance testers, and scanning electron microscopes. The results revealed that continuous drawing of Cu-1%Ag alloy wires led to elongation of the grains, resulting in a uniform and tightly fibrous microstructure. Moreover, the tensile strength of the alloy wire increased from 670 MPa to 783.9 MPa after a single pass with a deformation of 14%. Subsequently, when the wire was drawn at a speed of 500 m/min, the tensile strength further increased to 820.1 MPa. After annealing the phi 0.08 mm Cu-1% Ag alloy wire, an increase in annealing temperature up to 500 degrees C resulted in the wire's tensile strength decreasing from 820.1 MPa to 377.5 MPa. Simultaneously, the elongation increased from 1.94% to 15.21%, and the resistivity decreased from 1.931 Chi 10 (-8) Omega.m to 1.723 Chi 10 (-8) Omega.m. Additionally, when annealing was conducted at a rate of 80 m/min, the wire resistivity dropped to 1.635 Chi 10 (-8) Omega.m.
10.3390-mi16080857	14	strength; properties; conductivity; electrical; mechanical; cu-; grain; mpa; electrical conductivity; aging; precipitation; phase; mechanical properties; tensile; phases	A Cu-11.85Al-3.2Mn-0.1Ti shape memory alloy (SMA) with excellent superelasticity and shape memory effect was successfully fabricated via selective laser melting (SLM). Increasing the energy density enhanced grain refinement, achieving a 90% refinement rate compared to cast alloy, with an average width of similar to 0.15 mu m. Refined martensite lowered transformation temperatures and increased thermal hysteresis. Nanoscale Cu2TiAl phases precipitated densely within the matrix, forming a dual strengthening network combining precipitation hardening and dislocation hardening. This mechanism yielded a room-temperature tensile strength of 829.07 MPa, with 6.38% fracture strain. At 200 degrees C, strength increased to 883.68 MPa, with 12.26% strain. The maximum tensile strength represents a nearly 30% improvement on existing laser-melted quaternary Cu-based SMAs.
10.3390-min13060819	2	corrosion; surface; film; electrochemical; films; spectroscopy; layer; current; solution; potential; resistance; composition; x-ray; ions; showed	Igneous rocks from the Russian Far East contain Cu-Ag-Au microspherules with distinct exterior and interior structures, compositions and assemblages of Cu-rich micro-inclusions. Natural microspherules are compared in this study with technogenic Cu-Ag-Au microspherules, which are experimentally produced and extracted from gold scrap jewelry. The following set of diagnostic criteria are considered to distinguish natural from technogenic microspherules on a genetic basis as follows: (1) compacted-related features versus cellular appearance of the exterior; (2) lack of exsolution- or crystallization-related features in natural and domain-type internal structure in technogenic microspherules; (3) absence of spherical copper-oxide inclusions along with meniscus-type textural boundaries in technogenic mcirospherules; (4) pure copper-oxide composition of inclusions versus the common presence of Fe, Ni, Zn, Cu and Na in natural microspherules. The diagnostic characteristics of natural Cu-Ag-Au microspherules suggest extremely fast cooling rates during their formation, which is possible during violent explosive volcanic eruptions or injection of partially molten, pulverized metal alloys into shallow intra-crustal cavities and fault-related tectonic gashes.
10.3390-molecules28030981	2	corrosion; surface; film; electrochemical; films; spectroscopy; layer; current; solution; potential; resistance; composition; x-ray; ions; showed	This work studies two copper-based alloys as potential antimicrobial weapons for sectors where surface hygiene is essential. Effects of different alloying elements addition at the same Cu content (92.5% by weight) on the corrosion resistance and the antibacterial performance of two copper alloys were studied in an aerated disinfectant solution (0.25% v/v Aniosurf Premium (D)) by electrochemical corrosion, X-ray photoelectron spectroscopy (XPS), time-of-flight secondary ion mass spectroscopy (ToF-SIMS) and antibacterial tests. Results showed that the nature of the alloying elements had a clear influence on the corrosion resistance and antibacterial performance. Electrochemical impedance results and surface analyses demonstrate the presence of organic compounds bound on the substrate and that a film covers part of the total active surface and may act as a protective barrier by preventing the interaction between metal and solution, decreasing the antimicrobial performance of copper-based materials. Low zinc and silicon contents in copper alloys allows for better aging behavior in D solution while maintaining good antibacterial performance. The XPS and ToF-SIMS results indicated that artificial aging in disinfectant enhanced Cu enrichment in the organic film formed, which could effectively stimulate the release of Cu ions from the surface.
10.3390-nano11071772	-1		Carbon nanotubes (CNTs) reinforced double-layered Cu-Ni composite foams (Cu-Ni/CNT foams) were prepared through chemical plating and electrodeposition, for the purpose of combining enhanced mechanical and electromagnetic shielding properties. The microstructure characterization revealed a quite uniform dispersion of the CNTs embedded in the metal layers, even after heat treatments. The property testing showed the compressive strength, energy absorption capacity and electromagnetic shielding effectiveness (SE) of Cu-Ni/CNTs foams were significantly improved, as compared to Cu-Ni foams. The heat treatments of the composite foams resulted in an interdiffusion of the Cu and Ni layers, causing an increase of compressive strength and a slight decrease of average SE. The possible mechanisms of the property evolution are discussed.
10.3390-nano11092451	6	grain; deformation; strain; strength; dislocation; cu-; tensile; size; ecap; grain size; sfe; ductility; hardening; high; stress	We investigated the tensile properties of gradient nanograined Cu and CuAl samples prepared by plastic deformation. Tensile tests showed that the gradient nanograined Cu-4.5Al sample exhibits a uniform elongation of similar to 22% without any cracks, while the uniform elongation of the gradient nanograined Cu sample is only similar to 18%. Numerous mechanical twinning retards the softening of the nanograins and accommodates a high tensile ductility in the gradient nanograined Cu-4.5Al sample. This work indicates that mechanical twinning is a potential deformation mechanism to achieve high tensile ductility of nanograined materials.
10.3390-nano12091514	7	irradiation; shear; grain; ta; deformation; size; radiation; voids; nanocrystalline; simulations; similar; void; temperature; irradiated; boundaries	A state of the art, custom-built direct-metal deposition (DMD)-based additive manufacturing (AM) system at the University of Michigan was used to manufacture 50Cu-50Fe alloy with tailored properties for use in high strain/deformation environments. Subsequently, we performed preliminary high-pressure compression experiments to investigate the structural stability and deformation of this material. Our work shows that the alpha (BCC) phase of Fe is stable up to similar to 16 GPa before reversibly transforming to HCP, which is at least a few GPa higher than pure bulk Fe material. Furthermore, we observed evidence of a transition of Cu nano-precipitates in Fe from the well-known FCC structure to a metastable BCC phase, which has only been predicted via density functional calculations. Finally, the metastable FCC Fe nano-precipitates within the Cu grains show a modulated nano-twinned structure induced by high-pressure deformation. The results from this work demonstrate the opportunity in AM application for tailored functional materials and extreme stress/deformation applications.
10.3390-nano12091553	-1		We synthesized a combinatorial library of CuxN1-x alloy thin films via co-sputtering from Cu and Ni targets to catalyze graphene chemical vapor deposition. The alloy morphology, composition, and microstructure were characterized via scanning electron microscopy (SEM), energy dispersive x-ray spectroscopy (EDS), and X-ray diffraction (XRD), respectively. Subsequently, the CuxN1-x alloy thin films were used to grow graphene in a CH4-Ar-H-2 ambient at atmospheric pressure. The underlying rationale is to adjust the CuxN1-x composition to control the graphene. Energy dispersive x-ray spectroscopy (EDS) analysis revealed that a continuous gradient of Cu-x N1-x (25 at. % < x < 83 at%) was initially achieved across the 100 mm diameter substrate (similar to 0.9%/mm composition gradient). The XRD spectra confirmed a solid solution was realized and the face-centered cubic lattice parameter varied from similar to 3.52 to 3.58 angstrom, consistent with the measured composition gradient, assuming Vegard's law. Optical microscopy and Raman analysis of the graphene layers suggest single layer growth occurs with x > 69 at%, bilayer growth dominates from 48 at% < x < 69 at%, and multilayer (>= 3) growth occurs for x < 48 at%, where x is the Cu concentration. Finally, a large area of bi-layer graphene was grown via a CuxNi1-x catalyst with optimized catalyst composition and growth temperature.
10.3390-nano12183169	-1		Investigation of Cu(II) and Se(IV) electrochemical reduction processes in solutions with poly(ethylene glycol) (PEG) provides important theoretical guidance for the preparation of Cu-Se alloy films with stronger thermoelectric properties. The results reveal that PEG adsorbing on the electrode surface does not affect the electrochemical reduction mechanism of Cu(II), Se(IV), and Cu(II)-Se(IV), but inhibits the electrochemical reduction rates. The surface morphology and composition change with a negative shift in the deposition potentials. The Cu-Se alloy film, which was prepared at 0.04 V, was alpha-Cu2Se as-deposited and P-type thermoelectric material after annealing. The highest thermoelectric properties were as follows: Seebeck coefficient (alpha) was +106 mu V center dot K-1 and 1.89 times of Cu-Se alloy film electrodeposited in Cu(II)-Se(IV) binary solution without PEG; resistivity (rho) was 2.12 x 10(-3) omega center dot cm, and the calculated power factor (PF) was 5.3 mu W center dot cm(-1)K(-2) and 4.07 times that without PEG.
10.3390-nano13030386	-1		W-Cu composites are commonly subjected to coupled multiple fields in service, which imposes high requirements on their overall performance. In this study, the ultrafine-grained W-Cu composite was fabricated using the combination of electroless plating and spark plasma sintering. The wear resistance and high-temperature compressive properties of the ultrafine-grained W-Cu composite were investigated and compared with those of the commercial coarse-grained counterpart. Moreover, the underlying strengthening and wear mechanisms were also discussed. Here we show that the ultrafine-grained W-Cu composite exhibits superior integrated mechanical performance, making it a potential alternative to commercial W-Cu composites.
10.3390-nano13182605	3	sma; shape; shape memory; memory; smas; superelastic; bars; damping; cu-al-mn; mechanical; bending; applications; numerical; sma bars; material	Cu-Al-Ni is a high-temperature shape memory alloy (HTSMA) with exceptional thermomechanical properties, making it an ideal active material for engineering new technologies able to operate at temperatures up to 200 & DEG;C. Recent studies revealed that these alloys exhibit a robust superelastic behavior at the nanometer scale, making them excellent candidates for developing a new generation of micro-/nano-electromechanical systems (MEMS/NEMS). The very large-scale integration (VLSI) technologies used in microelectronics are based on thin films. In the present work, 1 & mu;m thickness thin films of 84.1Cu-12.4 Al-3.5Ni (wt%) were obtained by solid-state diffusion from a multilayer system deposited on SiNx (200 nm)/Si substrates by e-beam evaporation. With the aim of evaluating the thermal stability of such HTSMA thin films, heating experiments were performed in situ inside the transmission electron microscope to identify the temperature at which the material was decomposed by precipitation. Their microstructure, compositional analysis, and phase identification were characterized by scanning and transmission electron microscopy equipped with energy dispersive X-ray spectrometers. The nucleation and growth of two stable phases, Cu-Al-rich alpha phase and Ni-Al-rich intermetallic, were identified during in situ heating TEM experiments between 280 and 450 & DEG;C. These findings show that the used production method produces an HTSMA with high thermal stability and paves the road for developing high-temperature MEMS/NEMS using shape memory and superelastic technologies.
10.3390-nano14020143	-1		This work presents the effect of CeO2 nanoparticles (CeO2-NPs) on Cu-50Ni-5Al alloys on morphological, microstructural, degradation, and electrochemical behavior at high temperatures. The samples obtained by mechanical alloying and spark plasma sintering were exposed to a molten eutectic mixture of Li2CO3-K2CO3 for 504 h . The degradation of the materials was analyzed using gravimetry measurements and electrochemical impedance spectroscopy. Different characterization techniques, such as X-ray diffraction and scanning electron microscopy, were used to investigate the phase composition, parameter lattice, and microstructure of Cu-Ni-Al alloys reinforced with CeO2-NPs. The hardness of the composite was also examined using the Vickers hardness test. Gravimetry measurements revealed that the sample with 1 wt% CeO2-NPs presented the best response to degradation with a less drastic mass variation. Impedance analysis also revealed that by adding 1 wt% CeO2-NPs, the impedance modulus increased, which is related to a lower porosity of the oxide film or a thicker oxide layer. The microhardness also significantly increased, incorporating 1 wt% CeO2-NPs, which reduced with higher CeO2-NPs content, which is possibly associated with a more uniform distribution using 1 wt% CeO2-NPs in the Cu-Ni-Al matrix that avoided the aggregation phenomenon.
10.3390-nano14060487	-1		Nanoporous Cu foam is widely applied in many fields such as the packaging of electronic power devices. In this study, a sandwich-structured Cu-Zn eutectic alloy precursor composed of Cu0.53Zn0.47/Cu5Zn8/Cu0.53Zn0.47 is prepared through electroplating. The surface layer of the precursor, Cu0.53Zn0.47, has a flat surface with numerous grain boundaries, which effectively promotes its dealloying behavior. By contrast, Cu5Zn8 has a porous structure, which promotes the dealloying behavior at the center of the precursor. The dealloying of Cu0.53Zn0.47 is dominated by the coherent surface diffusion of Cu atoms, and the crystal lattice and orientation show no changes before and after dealloying. By contrast, the dealloying behavior of Cu5Zn8 requires the renucleation of Cu crystals; in this process, Cu atoms are transported to the surface of the layer by capillary forces to form clusters, which nucleate and grow.
10.3390-nano14181513	-1		Heterogeneous microstructures in Cu-Mo-W alloy thin films formed by magnetron co-sputtering immiscible elements with concentrated compositions are characterized using scanning transmission electron microscopy (STEM) and nanoindentation. In this work, we modified the phase separated structure of a Cu-Mo immiscible system by adding W, which impedes surface diffusion during film growth . The heterogeneous microstructures in the Cu-Mo-W ternary system exhibited bicontinuous matrices and agglomerates composed of Mo(W)-rich phase. This is unique, as these are the slower-diffusing species, contrasting past reports of binary Cu-Mo thin films that exhibited Cu-rich agglomerates. The bicontinuous matrices comprised of Cu-rich and Mo(W)-rich phases exhibited bilayer thicknesses of less than 5 nm. The hardness of these thin films measured using nanoindentation is reported and compared to similar multilayers and nanocomposites in binary systems.
10.3390-nano15161223	-1		In this study, we report a strategy to suppress the formation of large Cu-rich particles by adding excessive interstitial carbon into CuFeMnNi high-entropy alloys. With the increase in C contents in the CuFeMnNi HEAs annealed at 1000 degrees C, the size and area fraction of the submicron Cu-rich particles markedly decreased. Of note, the CuFeMnNi 1.5 at. %C alloy containing nanosized Cu-rich particles (13 nm) displayed excellent strength-ductility synergy, with yield strength of 695 +/- 10 MPa, ultimate tensile strength of 925 +/- 20 MPa, and ductility of 21.5%. This is because the addition of carbon significantly increases the diffusion speed of Cu atoms, thereby restraining the growth of Cu-rich nanoparticles. As a result, the comprehensive mechanical properties of the prepared HEAs were significantly enhanced. Additionally, the active diffusion channels induced by high-temperature short-time annealing significantly inhibited the grain growth, which improved the ductility. This work creates a new strategy for solving the dilemma caused by the large Cu-rich particles in the Cu-containing HEAs.
10.3390-pr10081507	2	corrosion; surface; film; electrochemical; films; spectroscopy; layer; current; solution; potential; resistance; composition; x-ray; ions; showed	Cu-Al-Nishape memory alloys (SMAs) are widely known for their better properties in comparison to other SMAs (lower production costs, increased ductility, enhanced machinability, reduced liquidus temperature, and decreased hysteresis), but there is still controversy in terms of the biological properties of these materials. The aim of this study was to evaluate biofunctional performances of Cu-Al-Ni alloy produced by continuous casting. The micro-chemical analysis was investigated by SEM/EDX. Immersion tests performed for seven days were used to estimate the quantity of Cu, Al, and Ni ions released in neutral pH and slightly acidic artificial saliva. To assess the biocompatibility of the Cu-Al-Ni alloy samples, MTT assay on fibroblasts and dental pulp cells was performed in indirect and direct contact with samples after 1,3, and 7 days.The study revealed that continuous casting enables the primary fabrication of Cu-Al-Ni rods with a shape memory effect. Samples immersed in artificial saliva with 6.5 pH value showed no significant amounts of released ions, despite the high concentration of copper in the alloy. However, in the acidic environment, the suppression of Cu was 0.14 mu g/cm(2), Al 1.9 mu g/cm(2), and Ni 0.73 mu g /cm(2), and as expected, it was confirmed that Cu-Al-Ni alloy is not corrosion resistant in an acidic environment. In conclusion, this study showed that biocompatibility concerns are related only to materials with a high Cu content in acidic environments. Oppositely, small doses of Cu ions promote cell proliferation, which might be useful in further attempts to enrich different biomedical materials with copper.
10.3390-pr13051451	14	strength; properties; conductivity; electrical; mechanical; cu-; grain; mpa; electrical conductivity; aging; precipitation; phase; mechanical properties; tensile; phases	High-performance copper alloys are crucial for integrated circuit lead frames due to their high density, multifunctionality, and low cost. High-performance copper alloys typically address the competing issues of high strength and high electrical conductivity through alloying and processing control methods. However, the traditional methods for developing these alloys are time-consuming, expensive, and complex processes. This study utilizes Explainable AI by employing machine learning (ML) and deep learning (DL) techniques to predict the hardness (HRC) and electrical conductivity (mS/m) based on the alloy composition, including Cr, Zr, Ce, and La, and the processing parameters, namely the aging time, of Cu-Cr-Zr alloys. A comprehensive dataset of 47 experimental Cu-Cr-Zr alloy samples, derived from prior experimental studies, was analyzed using feature engineering, correlation analysis, and explainability methods such as SHapley Additive exPlanations (SHAP). Various ML models, including ensemble methods like XGBoost, CatBoost, and AdaBoost, were evaluated for their predictive performance. The feature importance analysis revealed that the aging time and Zr content significantly influence the hardness, followed by Ce content, while Cr and La contents reveal a weak contribution to hardness values. Electrical conductivity is predominantly controlled by aging time, with a weak negative influence of the alloying elements. These findings align well with metallurgical principles, where microstructural refinement and precipitation behavior dictate the hardness and conductivity of Cu-Cr-Zr alloys. Hyperparameter tuning and model stacking further enhanced the predictive accuracy, with the final stacked models achieving R2 scores of 0.8762 for hardness within a training time of 1.739 s and 0.8132 for electrical conductivity within a training time of 1.091 s. These findings demonstrate the effectiveness of ML-driven approaches in material property predictions, providing valuable insights for material design and property processing parameter optimization.
10.3390-separations11060176	14	strength; properties; conductivity; electrical; mechanical; cu-; grain; mpa; electrical conductivity; aging; precipitation; phase; mechanical properties; tensile; phases	High-purity copper is essential for fabricating advanced microelectronic devices, particularly integrated circuit interconnects. As the industry increasingly emphasizes scalable and efficient purification methods, this study investigates the multi-physics interactions during the semi-continuous directional solidification process, utilizing a Cu-1 wt%Ag model alloy. Coupled simulation calculations examine the spatial distribution patterns of the impurity element silver (Ag) within semi-continuously solidified ingots under varying pulling rates and melt temperatures. The objective is to provide technical insights into the utilization of the semi-continuous directional solidification method for high-purity copper purification. The findings reveal that increasing the pulling rate and melt temperature leads to a downward shift in the solid-liquid interface relative to the mold top during processing. Alongside the primary clockwise vortex flow, a secondary weak vortex emerges near the solid-liquid interface, facilitating the migration of the impurity element Ag toward the central axis and amplifying radial impurity fluctuations. Furthermore, diverse pulling rates and melt temperature conditions unveil a consistent trend along the ingot's height, which is characterized by an initial increase in average Ag content, followed by stabilization and then a rapid ascent during the late stage of solidification, with higher pulling rates and melt temperatures expediting this rapid ascent. Leveraging these insights, a validation experiment using 4N-grade recycled copper in a small-scale setup demonstrates the effectiveness of the semi-continuous directional solidification process for high-purity copper production, with copper samples extracted at 1/4 and 3/4 ingot heights achieving a 5N purity level of 99.9994 wt% and 99.9993 wt%, respectively.
10.3390-sym16050545	3	sma; shape; shape memory; memory; smas; superelastic; bars; damping; cu-al-mn; mechanical; bending; applications; numerical; sma bars; material	Shape memory alloys (SMAs) represent an exceptional class of smart materials as they are able to recover their shape after mechanical deformation, making them suitable for use in actuators, sensors and smart devices. These unique properties are due to the thermoelastic martensitic transformation that can occur during both thermal and mechanical deformation. Cu-based SMAs, especially those incorporating Al and Ag, are attracting much attention due to their facile production and cost-effectiveness. Among them, Cu-Al-Ag SMAs stand out due to their notably high temperature range for martensitic transformation. In this study, a Cu-based SMA with a new ternary composition of Cu-10Al-7Ag wt% was prepared by arc melting and the samples cut from this casting alloy were quenched in water. Subsequently, the phase composition and the development of the microstructure were investigated. In addition, the morphology of the martensite was studied using advanced techniques such as electron backscatter diffraction (EBSD) and transmission electron microscopy (TEM). The analyzes confirmed the presence of martensitic structures in both samples; mainly 18R (beta 1 ') martensite was present but a small volume fraction of (gamma 1 ') martensite also was noticed in the as-quenched sample. The observation of fine, twinned martensite plates in the SMA alloy with symmetrically occurring basal plane traces between the twin variants underlines the inherent correlation between microstructural symmetry and the properties of the material and provides valuable insights into its behavior. The hardness of the quenched sample was found to be lower than the as-cast counterpart, which can be linked to the solutioning of Ag particles during the heat treatment.
10.36410-jcpr.2022.23.4.490	16	wear; composite; composites; powders; milling; particles; powder; wt; sliding; friction; hardness; matrix; mechanical; surface; properties	The goal of this research is to evaluate the electrical, dry sliding wear and corrosion behaviour of copper-zinc alloy reinforced with Ni and Si through Powder Metallurgy (P/M) technique. Six different wt. % of novel copper-zinc alloy are considered for this research study namely 90Cu-10Zn, 88.16Cu-10Zn-1.5Ni-0.34Si, 85Cu-15Zn, 83.16Cu-15Zn-1.5Ni-0.34Si, 80Cu-20Zn and 78.16Cu-20Zn-1.5Ni-0.34Si. The fabricated composites were characterized by using Scanning Electron Microscope (SEM) with Energy Dispersive Spectroscopy (EDS) line mapping. The electrical, wear and corrosion behaviour of the fabricated composites was assessed. The hardness of the fabricated composites was evaluated using Vickers Hardness Tester. The electrical conductivity was assessed using four-point probe tester. The result shows a significant improvement on electrical and tribological properties by increasing the wt% of Zn, Ni and Si led of the composites. The research results concludes that 78.16Cu-20Zn-1.5Ni-0.34Si composite possessed better hardness about 287 HV and the electrical conductivity about 121% IACS. The investigation result shows that Zn acts as a vital role to enhance the properties in all aspects. Also, the experimentation results portrays that Cu-20Zn-1.5Ni-0.34Si composite possessed better specific wear rate and coefficient of friction such as 1.85 * 10(-5) mm(3) /N-m and 0.29 respectively
10.3749-canmin.51.2.253	2	corrosion; surface; film; electrochemical; films; spectroscopy; layer; current; solution; potential; resistance; composition; x-ray; ions; showed	The Pagoni Rachi/Kirki Cu-Mo +/- Re +/- Au deposit is a telescoped porphyry-epithermal system that contains molybdenite with up to 4.7 wt% Re and the rare mineral rheniite (ReS2). The deposit is spatially related to an Oligocene, calc-alkaline hornblende-biotite-bearing granodiorite-tonalite porphyry stock; however, a genetic link to a buried stock of quartz-feldspar porphyry magma beneath Pagoni Rachi cannot be excluded. Alteration types and vein relationships suggest that mineralization can be divided into four paragenetic stages, which are, from early to late: (1) sodic/potassic-calcic alteration with quartz-and magnetite-bearing veins (A-and M-type) and distal propylitic alteration, (2) sodic/potassic alteration with quartz-pyrite-chalcopyrite-molybdenite veins (B-type), (3) sericitic alteration with transitional porphyry to epithermal pyrite-chalcopyrite-molybdenite veins (D-type), and (4) argillic alteration with quartz-calcite base metal and precious metal rich veins (E-type) with epithermal affinity. Bulk ore analyses and mineralogical data are consistent with deposition of precious metals in all mineralization stages: electrum in A-and M-type veins is spatially associated with bornite and chalcopyrite, whereas tellurides (cuprian hessite, stutzite, petzite) and Ag-Au alloy occur in the epithermal veins. The D-type veins contain the highest gold grades (up to 5 g/t) and include Ag-, Bi-, Te-, and Se-bearing minerals indicating a possible genetic relationship with E-type epithermal veins. Fluid inclusion data indicate that A-and B-type veins (porphyry style mineralization) were deposited at 360-510 degrees C and at pressures up to 690 bars (<2 km depth) in A-veins and up to 360 bars (<1.5km depth) in B-veins, from boiling hydrothermal fluids. This process produced coexisting low to moderately saline (1.7-10.7 wt% NaCl equiv.) and highly saline (36->74 wt% NaCl equiv.) fluids. Subsequent dilution of the moderately saline fluid formed a lower temperature (210-340 degrees C), less saline (1.4-2.9 wt% NaCl equiv.) fluid in late epithermal E-veins. Based on the Au and Re grades, Cu/Mo ratios, presence of rheniite and the extremely high Re content of molybdenite, Pagoni Rachi may be considered as a distinct class of porphyry deposits, a Cu-Mo +/- Re +/- Au system that is derived from rocks transitional between calc-alkalic and alkalic porphyries. Its similarity with other Re-Au enriched porphyry-style deposits in northeastern Greece indicates that this area may represent a new Au-Re-Te metallogenetic province.
10.3762-bjnano.7.143	7	irradiation; shear; grain; ta; deformation; size; radiation; voids; nanocrystalline; simulations; similar; void; temperature; irradiated; boundaries	Scanning electron microscopy transmission Kikuchi diffraction is able to identify twins in nanocrystalline material, regardless of their crystallographic orientation. In this study, it was employed to characterize deformation twins in Cu/10 wt% Zn processed by high-pressure torsion. It was found that in 83% of grains containing twins, at least one twin intersects with a triple junction. This suggests that triple junctions could have promoted the nucleation of deformation twins. It should be cautioned that this technique might be unable to detect extremely small nanoscale twins thinner than its step size.
10.3938-jkps.63.555	9	magnetic; magnetization; magnetoresistance; temperature; superparamagnetic; annealing; gmr; field; magnetic properties; ferromagnetic; granular; samples; magnetic field; melt-spun; particles	Cu-10 at% Ni-5 at% Co specimens containing nano-scale magnetic particles were investigated with respect to the relationship between the microstructure and the magnetic properties, by using a transmission electron microscope (TEM), a SQUID magnetometer and a magnetic thermobalance. The present TEM observations revealed that small magnetic precipitates were formed in a copper matrix in a specific manner that has never been reported in conventional precipitation alloys consisting of non-magnetic elements. The SQUID measurements indicated that a specimen annealed for a short period had a large coercive force, although the force decreased for longer annealing treatments. The magnetic thermogravity scan in the temperature range of 300-1223 K showed that the alloy specimen had a paramagnetic state between two ferromagnetic regions.
10.3989-revmetalm.242	16	wear; composite; composites; powders; milling; particles; powder; wt; sliding; friction; hardness; matrix; mechanical; surface; properties	Electrical discharge machining (EDM) is mainly utilized for the die manufacturing and also used to machine the hard materials. Pure Copper, Copper based alloys, brass, graphite, steel are the conventional electrode materials for EDM process. While machining with the conventional electrode materials, tool wear becomes the main bottleneck which led to increased machining cost. In the present work, the composite tool tip comprises 80% Copper and 20% silicon carbide was used for the machining of hardened D2 steel. The powder metallurgy route was used to fabricate the composite tool tip. Electrode wear rate and surface roughness were assessed with respect to the different process parameters like input current, gap voltage, pulse on time, pulse off time and dielectric flushing pressure. During the analysis it was found that Input current (Ip), Pulse on time (Ton) and Pulse off time (Toff) were the significant parameters which were affecting the tool wear rate (TWR) while the Ip, Ton and flushing pressure affected more the surface roughness (SR). SEM micrograph reveals that increase in Ip were used to develop machine learning based surrogate models. Three machine learning (ML) models are random forest, polynomial regression and gradient boosted tree. The predictive capability of ML based surrogate models was assessed by contrasting the R2 and mean square error (MSE) of prediction of responses. The best surrogate model was used to develop a complex objective function for use in firefly algorithm-based optimization of input machining parameters for minimization of the output responses. leads to increase in the wear rate of the tool. The data obtained from experiments
10.4028-www.scientific.net-MSF.204-206.449	-1		Isothermal grain growth of Cu (700 degrees C) and the alloy CuZn (600 degrees C and 800 degrees C) was quantitatively studied by optical microscopy and related to both global and local texture analysis carried out by neutron diffraction and EBSP. The global grain growth kinetics in both materials is characterized by a period of rapid grain coarsening with a growth exponent n > 0.5 followed by a stage with much slower increase of the grain size (n much less than 0.5). By separation of the corresponding grain size distributions by means of the EBSP-technique it can be shown directly that in brass the first period of grain growth is related to a significant change of the main texture components while in copper it is accompanied essentially by a sharpening of the texture, Computer simulation based on the model of grain growth of ABBRUZZESE and LUCKE [1] illustrates that the experimental data are in good agreement with the theoretical predictions concerning the normal grain growth in textured materials.
10.4028-www.scientific.net-MSF.215-216.133	-1		Recent results in directional solidification experiments with Cu-Mn alloys with compositions near the melting point minimum showed that this binary alloy is well suited for investigations on fundamental aspect of macrosegregation and interface morphology as well. Several experiments with alloy concentrations lower than 32.8 wt% Mn carried out on Earth confirm the existence of the melt convection whereas purely diffusive experiment conditions were realized in microgravity during the D-2 Spacelab Mission. Increasing of the solidification velocity results in cellular and dendritic solid-liquid interface morphologies. From excellently metallographical prepared cross-sections, especially the spatio-temporal development of cellular patterns, i.e. mainly the primary spacings, regularity and anisotropy of the cells has been investigated providing the basis for the improvement of theoretical models.
10.4028-www.scientific.net-MSF.235-238.571	4	transformation; martensite; martensitic; phase; shape; beta; memory; shape memory; temperature; temperatures; martensitic transformation; gamma; transformation temperatures; effect; thermal	Rapid solidification was used to prepare metastable Cu Zn alloys having a composition close to the beta-brass interval. In the as-spun condition ribbons had a body centred cubic (bcc) crystal structure, typical of beta-brass. After isothermal heat treatments at 400 degrees C such a structure was turned into a mixture of the initial bcc one plus the alpha phase of brass, having a face centred cubic (fee) structure. A similar transformation could be also induced by ball-milling. Indeed the mentioned mixture was evolved from the same initial cubic phase by milling the as spun ribbons in a high energy planetary mill. From x-ray diffraction data it was not only possible to follow the phase evolution, but also to evaluate the composition of the two Cu-Zn phases from lattice parameters data. The a phase obtained by ball-milling was estimated to have off equilibrium compositions. Equilibrium conditions were established by heat treating the milled powders at selected temperatures. The stability of the different structures obtained in the course of the present investigation was checked using Differential Scanning Calorimetry (DSC) measurements. In the milled samples, when heated up in the calorimeter, it was noticed the occurrence of exothermic irreversible transformations, to be ascribed to recrystallisation and recovery.
10.4028-www.scientific.net-MSF.269-272.843	-1		Mechanical alloying has been used to produce nanocrystalline copper. Data on mechanical and electrochemical of nanocrystalline materials have been limited by the difficulty in producing nanocrystalline materials for characterization and evaluation. The results of the given study show that the densification of compacts nc-Cu depends on the temperature and the pressure. An enhancement of resistance corrosion of nc-Cu compacts have been observed.
10.4028-www.scientific.net-MSF.294-296.169	6	grain; deformation; strain; strength; dislocation; cu-; tensile; size; ecap; grain size; sfe; ductility; hardening; high; stress	Intergranular stress-corrosion cracking (SCC) in a alpha Cu-Al alloy has been investigated on bicrystals shaped to a tapered double cantilever beam (TDCB) specimen. The SCC property was estimated by the relationship between crack growth rate da/dt and energy release rate g. The bicrystal specimens of two kinds (Sigma 5 and random boundaries) were prepared, During the SCC tests, the applied load continued to decrease and was saturated subsequently, Surface observation after the SCC tests revealed that the crack propagated along the Grain Boundary. In both specimens, the da/dt-g curves calculated from the load relaxation could be divided into Regimes I and II at low and high g-values, respectively. The crack growth rates increased with the increasing g-value in Regime 1 and was independent of the g-value in Regime II. Both of the threshold g-value in Regime I and the crack growth rate in Regime II, which can characterize the SCC properties, were certainly different between the specimens. It is likely that such differences are attributed to the GB structure and the geometry of operative slip systems.
10.4028-www.scientific.net-msf.294-296.605	-1		The effect of pressure and temperature on the distribution function for the activation energy and activation volume of the discontinuous precipitation reaction in a Cu-7.5 at% In alloy has been studied. For each pressure and temperature the distribution functions for the activation energy and activation volume for the grain boundary (GB) diffusivity were determined. It was found that the average activation volume increases from 0.75 to 1.5 atomic volumes, when the temperature is increased from 310 to 370 degrees C. At each temperature the activation energy and activation volume vary within 15% to 30% around the average.
10.4028-www.scientific.net-MSF.408-412.1651	-1		The evolutions of surface morphologies in sputtered and electroplated Copper films during annealing were investigated. After annealing at 435degreesC, in the electroplated Copper films grooves along the grain boundaries were observed, while in the sputtered films voids were observed at the triple junctions and along the grain boundaries. The textures and grain boundary characteristics of two films were analyzed. The densities of low energy boundaries were analyzed to explain the difference of the surface morphologies.
10.4028-www.scientific.net-MSF.442.115	-1		Copper-carbon composites, nominally containing up to 50 volume percent additions of graphite, were produced from thoroughly ball-milled powder mixtures by sintering under vacuum at different temperatures in the range from 400 to 800 degreesC. The microstructure of as-milled powders and sintered products have been mainly characterized by scanning and transmission electron microscopies, x-ray diffraction and energy-dispersive x-ray spectrometry. SEM and TEM characterization of the as-milled powders showed that the mixing of the original copper and graphite powders reached submicrometer level, with a tendency for the graphite to completely coat the copper particles. XRD and TEM characterization also indicated the presence of substantial amounts of copper oxides in the mechanically alloyed powders. After sintering, the dispersion of graphite in the copper matrix remained at the submicrometer scale for sintering temperatures up to 600 degreesC. However, specimens sintered at 800 degreesC showed a clear separation process of the copper and carbon constituents. The amount of oxides found in the powder mixtures decreased as the sintering temperature increased, particularly in the Cu-50 vol% materials, but this occurred at the expense of gas evolution as a result of the reduction of the oxides by the carbonaceous component and, in some cases, unacceptable porosity levels. It is shown that composite copper-graphite composite powders produced by means of the mechanical alloying process have the potential of providing considerable flexibility in the control of microstructural features in the bulk composite materials derived therefrom.
10.4028-www.scientific.net-MSF.465-466.27	6	grain; deformation; strain; strength; dislocation; cu-; tensile; size; ecap; grain size; sfe; ductility; hardening; high; stress	Copper and copper aluminum (2 and 6 wt% aluminum) with two orientations, [001] and [134], were subjected to high intensity laser shocks (energy levels of 40-300 J; energy densities of 15-70 MJ/m(2) and durations of 2.5 ns). The defects created were characterized by transmission electron microscopy. The slip-twinning transition was determined quantitatively in terms of both orientation and stacking fault energy. The threshold twinning pressure for copper oriented to [001] decreases with decreasing stacking fault energy from 40 GPa for pure copper to less than 20 GPa for copper-2 wt% aluminum. For the [134] orientation, pure copper twinned at pressures on the order of 60 GPa, and whereas the copper-2 wt% aluminum alloy readily twinned at pressures less than 40 GPa. The results are rationalized in terms of a criterion in which slip and twinning are considered as competing mechanisms. A constitutive description using a modified MTS (mechanical threshold stress) constitutive equation applied incorporating slip and twinning in terms of orientation, stacking fault energy, temperature rise due to shock heating, and strain rate. The predictions are in agreement with experiments. The constitutive description provides a rationale for the experimental results; the calculated thresholds for [001] and [134] are, respectively: 17 GPa and 25 GPa for pure copper, 9 GPa and 13 GPa, for Cu-2wt% Al and 1 GPa and 2 GPa for Cu-6wt% Al.
10.4028-www.scientific.net-MSF.482.71	6	grain; deformation; strain; strength; dislocation; cu-; tensile; size; ecap; grain size; sfe; ductility; hardening; high; stress	Based on the Taylor theory, a critical length scale is defined as the minimum dislocations cell size obtained at the maximum work-hardening for metals and alloys. When grain size is smaller than this length scale, corresponding also to a critical dislocation mean free path, new behaviours occur; such as ductility and strength, near perfect elasto-plasticity, high strain-rate sensitivity. Bulk samples are fabricated from Cu nanopowders (particle size 50 nm) by powder metallurgy techniques. The final grain size is comprised between the critical mean free path, evaluated at 130 run and the size where transition to the so-called nano regime occurs (when unit dislocation no longer exists below 30 nm for Cu). Tensile tests are carried and microstructural analysis are performed before and after deformation.
10.4149-km_2014_6_337	6	grain; deformation; strain; strength; dislocation; cu-; tensile; size; ecap; grain size; sfe; ductility; hardening; high; stress	An oxygen free high conductivity (OFHC) copper was subjected to maximum 13 ECAP passes to achieve a sufficiently high degree of deformation. Strength properties (yield stress and ultimate tensile strength) show obvious increase up to the 4(th) pass. In the 6(th) ECAP pass, the yield stress and ultimate tensile strength are stabilized at a maximum of 449 MPa. Microstructure studies showed that the 1(st) ECAP pass caused a significant increase of dislocation density. These dislocations are arranged in cells, forming dense dislocation walls at low-angle subgrains. After the 5(th) ECAP pass, well-defined equiaxed ultrafine grains of diameter approximately 500 nm had emerged forming high-angle grain boundaries. The defect density studies carried out by positron annihilation spectroscopy method revealed an increase in a defect density (vacancies, dislocations) up to the 4th pass, consequently with number of ECAP passes increasing, decrease in defects density (seen by positrons) was observed.
10.4149-km_2017_3_149	16	wear; composite; composites; powders; milling; particles; powder; wt; sliding; friction; hardness; matrix; mechanical; surface; properties	In this study, effects of ultra-dispersed nanodiamond content on the microstructure and wear properties of Cu-15 wt% Ti matrix composite were investigated. Samples were prepared by mechanical alloying and sintering at 890 degrees C for 2 h under H-2 gas atmosphere. Microstructural changes and dry sliding wear characterizations of sintered samples were investigated by a field emission scanning electron microscope (FESEM), and their phase characteristics were carried out using X-ray diffractometer (XRD). Electron microscopy investigations revealed that a good bonding between nanodiamond particles and Cu matrix could not be maintained due to the formation of free copper layers and the presence of high oxygen amount at the interface. The results taken from worn surfaces showed that high content of nanodiamond (10 wt%) with oxide particles led to low wear resistance due to poor bonding between Cu 15 wt% Ti matrix and nanodiamond particles which were pulled out during dry sliding wear.
10.4149-km_2017_6_431	16	wear; composite; composites; powders; milling; particles; powder; wt; sliding; friction; hardness; matrix; mechanical; surface; properties	In this study, the effects of cryogenic treatment (CT) on the performance of CuCrZr alloy and Cu electrodes in electro discharge machining (EDM) of AISI P20 tool steel were investigated experimentally. For this purpose, a group of electrodes were cryogenically treated at 140 degrees C for 30 min and then tempered at 175 degrees C for 1 h . The tool performance was evaluated in terms of electrode wear rate (EWR), material removal rate (MRR), and average surface roughness (Ra) of machined surfaces. The EDM tests were conducted at pulse currents of 4, 8, 12, and 16 A and pulse durations of 25 and 50 is. Experimental results showed that treated electrodes were less worn than the untreated ones and the Ra values of machined surfaces decreased when cryo-treated electrodes were used. Also, it was observed that pulse current is the most effective parameter in the EDM process.
10.4149-km_2019_1_1	-1		Composite materials based on Cu matrix have a wide range of applications because of their extraordinary features such as high thermal conductivity and high mechanical strength . The preparation of Cu-ZrB2 and CuCr1Zr-ZrB2 composites via gas pressure infiltration technology is described in this work. In contrast to most ceramic materials, ZrB2 is electrically and thermally conductive. All tested samples, i.e. prepared from the ZrB2 porous preform with a porosity of 40% were infiltrated with molten Cu or CuCr1Zr alloy. Microstructure and homogeneity after infiltration were examined by SEM-EDS microscopy. The interface between the Cu matrix and ZrB2 ceramics was explored by TEM microscopy. As-infiltrated composites were thermally cycled up to 800 degrees C with heating and cooling rates of 3 degrees C min(-1) in an argon atmosphere.
10.4149-km_2019_1_121	-1		The precipitation of nano-sized Cr clusters was investigated in a commercial Cu-lCr-0.1Zr (wt%) alloy processed by equal-channel angular pressing and subsequent aging at 550 degrees C for 4 h using Small-Angle Neutron Scattering (SANS) measurements and High-Angle Annular Dark-Field-Scanning Transmission Electron Microscopy (HAADF-STEM). The size and volume fraction of the nano-sized Cr clusters were estimated using both techniques. The parameter values assessed by SANS (d similar to 3.2 nm, F-v similar to 1.1 %) agreed reasonably with those by HAADF-STEM (d similar to 2.5 nm, F-v similar to 2.3 %). In addition to the nano-sized Cr clusters, HAADF- -STEM indicated the presence of rare cuboid and spheroid sub-micronic Cr particles measuring approximately 380-620 nm in mean size. Both techniques did not evidence the presence of intermetallic CuxZry phases within the aging conditions.
10.4149-km_2019_1_95	16	wear; composite; composites; powders; milling; particles; powder; wt; sliding; friction; hardness; matrix; mechanical; surface; properties	Cu/ZrB2 and CuCr1Zr/ZrB2 composites were prepared by gas pressure infiltration technology. The ZrB2 powder was used as reinforcement. No interfacial reaction took place for Cu, or CuCr1Zr matrix as confirmed by transmission electron microscopy (TEM). The thermal stability of composites was very good, i.e. without any indication of possible disintegration. Composites exhibit high structural stability when subjected to 5 consecutive heating/cooling cycles to 800 degrees C. Maximums of relative elongations recorded for particular heating/cooling cycles slightly increased for Cu/ZrB2 composite and slightly decreased for CuCr1Zr/ZrB2 composite. However, the differences are negligible.
10.4149-km_2020_4_293	4	transformation; martensite; martensitic; phase; shape; beta; memory; shape memory; temperature; temperatures; martensitic transformation; gamma; transformation temperatures; effect; thermal	Two quaternary Cu-Al-Mn-Ag shape memory alloys with nearly constant Al and Ag contents and variable content of Mn were prepared by arc melting of pure metals. Experimentally determined overall compositions of the investigated alloys were Cu-9.4%Al-1.1%Mn-3.7%Ag (alloy 1) and Cu-9.5%Al-5.6%Mn-3.9%Ag (alloy 2) (in wt%). Microstructures of the prepared samples were investigated in the as-prepared condition and after heat treatment, which included solution annealing at 850 degrees C and quenching into the ice water. The effects of alloy composition and heat treatment on the microstructure and transformation temperatures of the investigated shape memory alloys were investigated using scanning electron microscopy with energy dispersive spectroscopy (SEM-EDS) and differential scanning calorimetry (DSC). It was determined that alloy with low Mn content (alloy 1) exhibits martensite + alpha microstructure in the as-prepared state and the as-quenched state. The volume fraction of alpha-phase was much larger in the as-prepared condition. Ag was uniformly distributed between the co-existing phases. The microstructure of the alloy with a higher content of Mn (alloy 2) was fully martensitic in both investigated conditions. Martensite and austenite transformation temperatures were investigated using DSC.
10.5006-1.3278300	2	corrosion; surface; film; electrochemical; films; spectroscopy; layer; current; solution; potential; resistance; composition; x-ray; ions; showed	The corrosion behavior of copper-brazed joints, with a ternary filler metal, Cu-P-Ag (74.75% Cu, 7.25% P, 18% Ag) in the form of wire for brazing, was studied in 400 g/L, 700 g/L, 850 g/L, and commercial lithium bromide (LiBr) solution (850 g/L LiBr solution with 4.3 g/L lithium chromate [Li2CrO4] as inhibitor and 0.08 g/L lithium hydroxide [LiOH] as pH control) at 25 degrees C. Corrosion resistance was studied on three different geometrical types of electrodes designed to study copper-brazed joints. Type 1 or filler metal (FM) was tested to study the influence of the alloying elements on the copper corrosion resistance. Type 2 or melted filler metal (MFM) was used to study the thermal effect on the filler metal corrosion behavior. Type 3 Cu//(Cu-P-Ag) or brazed copper was configured to study the brazing method, the melting process on copper, and the galvanic effect on copper-brazed joints. Corrosion resistance was estimated from the polarization curves. Metallographic examination was carried out to characterize the microstructure of the samples. The results showed that Li2CrO4 improved corrosion resistance of brazed joints with inhibiting efficiencies up to 95%. In the commercial solution, the alloying elements in copper improved corrosion resistance; however, the melting process shifted open-circuit potential (E-OCP), critical potential (E-c), and corrosion potential (E-corr) toward more negative values. Galvanic studies showed that copper behaved as the anode when coupled to the simulated copper-brazed joint, Type 3 configuration; however, it behaved like the cathode with the melted filler metal in the most concentrated solutions.
10.5006-1.3280653	2	corrosion; surface; film; electrochemical; films; spectroscopy; layer; current; solution; potential; resistance; composition; x-ray; ions; showed	Potential-time curves are constructed for the Cu electrode in aerated sodium hydroxide (NaOH) solutions devoid of and containing increasing concentrations of S2- ions. In sulfide-free solutions, the steady-state potentials (E-st) are reached from negative values indicating oxide film thickening. Lower concentrations of S2- ions enhance oxide film thickening and the potential moves more in the noble direction. Increasing the S2- ion content causes the potential to fluctuate in the active and noble directions during a time span that depends on the S2- ion content. This behavior is attributed to the preferential formation of copper oxide and/or copper films. Higher concentrations of S2- ions, on the other hand, cause the potential to change markedly into the active direction, denoting the formation of Cu2S. Within this range of S2- ion concentration, the E-st varies with [S2-] according to: E-st = E degrees-0.059 log [S2-] at 25 degrees C, while E degrees varies with the pH of the solution to give a straight line with a slope of 29 mV/pH unit. A mechanism is proposed that involves the formation of CuHS as an intermediate step in the process of Cu2S formation.
10.5006-1.3280797	2	corrosion; surface; film; electrochemical; films; spectroscopy; layer; current; solution; potential; resistance; composition; x-ray; ions; showed	Galvanic influence of Alloy 33 (UNS R20033) and titanium (Grade 2) on copper was studied in lithium bromide (LiBr) solutions (400, 700, and 850 g/L chromate containing commercial solution). Temperature effect was also analyzed by imposing a heating/cooling cycle to the samples during a 10-h period (from 25degreesC to 80degreesC at 0.5degreesC/min), during a 2-h period (from 80degreesC to 25degreesC at 0.5degreesC/min), and during the last 2 h (maintained at 25degreesC). The galvanic potential and the galvanic current were measured with a zero-resistance ammeter (ZRA) during the temperature cycle. Images of the electrode surfaces were captured simultaneously with the recorded electrochemical signal caused by corrosion processes without disturbing the electrochemical system. The experimental device consists of an electrochemical system with an horizontal electrochemical cell coupled to a microscope, camera, and a system of image acquisition. Copper is always the anodic element of the Cu-Alloy 33 pair, however it behaves cathodically or anodically, depending on the temperature and the medium, when coupled to titanium. Copper was the cathodic element of, the Cu-Ti pair in 700 g/L LiBr solution and commercial solution at room temperature. In these cases, the cooling stage generated the highest galvanic current. Temperature effect on the corrosion of the Cu-Alloy 33 pair duplicated >52degreesC according to the current slope values observed during the second heating hour The cooling period also caused a galvanic current increase between 70degreesC and 65degreesC. Initial current and potential values were not recovered. at the end of the cycle in the commercial LiBr solution.
10.5006-1.3290368	2	corrosion; surface; film; electrochemical; films; spectroscopy; layer; current; solution; potential; resistance; composition; x-ray; ions; showed	There are apparently conflicting observations about the influence of seawater temperature on the immersion corrosion of copper-nickel alloys, with both increases and decreases in temperature having been observed. During the 1980s, ASTM sponsored a worldwide corrosion study, which included 90:10 copper-nickel (UNS C070600). At first sight there is no order in the results regarding the effect of seawater temperature. However when the results are examined in detail, allowing for water velocity and environmental conditions and carefully I considering the implications of previous laboratory and field studies, some order can be obtained. This shows that a relationship between corrosion and temperature in the range of 10 degreesC to 400 degreesC can be proposed, which is consistent with previous observations.
10.5006-1.3683224	2	corrosion; surface; film; electrochemical; films; spectroscopy; layer; current; solution; potential; resistance; composition; x-ray; ions; showed	The nondestructive electrochemical impedance spectroscopy (EIS) method was used to study the influence of a surface film (spontaneously formed and modified by an inhibitor) on copper in a saline solution, pH 7.9, at the open-circuit potential (E-OCP) under static and fluid impingement conditions, i.e., under the real conditions of copper application. EIS parameters obtained in situ in a wide frequency range were correlated to the phenomena that occur simultaneously at different time scales: the charge-transfer resistance, capacitance and resistance of the surface film, and the resistance to the transport of copper species through the film. The diffusion coefficient, the concentration of diffusing species, and the passive (corrosion) current density were calculated using the equations derived for the finite-length Warburg impedance. The influence of turbulent fluid flow on the anodic and cathodic kinetics of copper in a saline solution, pH 7.9, was discussed on the basis of potentiodynamic measurements.
10.5755-j01.mech.22.4.16165	-1		The objective of this study is to investigate experimentally the cyclic deformation in a planar slip material using acoustic nonlinearity. Observation and characterization of the dislocation substructure are conducted using an electron microscope. The acoustic nonlinearity was obtained by a superharmonic generation technique for different levels of fatigue-damaged specimens. The microstructural effects on nonlinearity are discussed in terms of the extent of planar array dislocations in the substructures after the low-cycle fatigue. The acoustic nonlinearity of Cu-Zn alloy increased with the number of fatigue cycles due to the evolution of dislocation substructures. Consequently, acoustic nonlinearity could be a potential index to characterize cyclic deformation with respect to dislocation substructures.
10.5755-j01.ms.26.1.21060	-1		The effect of high-density electric current pulse (ECP) on the solidification of Cu-37.4 wt%Pb monotectic alloy melt was investigated. The microstructure formation mechanisms of ECP were clarified according to liquid metal cluster theory. The results demonstrated that with ECP treatment, the microstructure of Cu-Pb monotectic alloy became finer, the distribution of Pb phase in the matrix was more even and the solute trapping was significantly apparent. Based on the metal liquid cluster theory under ECP, the solid solubility increase result might be due to the salvation clusters increase under the action of pulse current, leading to the binding force increase among solute atoms and solvent atoms. Simultaneously, the aforementioned results were verified through the Differential Scanning Calorimetry (DSC) curve analysis. The results of hardness test, anti-friction test and wear- resistance test show that the ECP can enhance the hardness, improve the properties of anti-friction and wear-resistance of the alloy.
10.5755-j02.ms.36919	-1		The thermo-stability of microstructure during isothermal annealing at 900 degrees C and 1000 degrees C in a cold-worked Cu-Al2O3 composite with 0.1 wt%Al content and its effect on resistance to softening were investigated in this paper. The results reveal that the microstructure following cold deformation consists of a Cu matrix with a refined grain size and high-density dislocations, accompanied by dispersed Al2O3 nanoparticles exhibiting an extremely low volume fraction. During isothermal annealing at 900 degrees C, the Al2O3 nanoparticles can strongly restrict the migration of the dislocations and suppress the recrystallization of the fine-grained Cu matrix by the Zener pinning effect. Furthermore, the presence of pinned dislocations facilitates the formation of sub-grain boundaries comprising high-density dislocations. Consequently, the CuAl2O3 composite with 0.1 wt% Al content exhibits remarkable thermo-stability in its microstructure due to the incorporation of Al2O3 nanoparticles, resulting in a significantly elevated softening temperature of up to 1000 degrees C and thereby demonstrating excellent resistance against softening. However, the observed phenomenon of softening after isothermal annealing at 1000 degrees C for 5 hours can be attributed to extensive recrystallization growth that promotes twin boundary formation, primarily caused by the weakening Zener pinning effect resulting from Oswald ripening ofAl2O3 and rod-like Al2O3 formation.
10.7566-JPSJ.88.084601	-1		A part of phonon dispersion relation of gamma-Fe precipitates in Cu matrix was determined for the first time using neutron inelastic scattering. At a room temperature, dispersion curves for the [100] T- and [110] T-1-branches show rather high energies and almost similar values to those for fcc-Fe-70 Mn-30 alloy. However, phonon energies of gamma-Fe precipitates give a sign of strong softening with raising temperature and they decrease by about three times faster than those for Cu host. As a possible cause of the rapid softening of phonons, a metastable state of gamma-Fe precipitates is discussed.
10.7567-JJAP.53.05HA11	2	corrosion; surface; film; electrochemical; films; spectroscopy; layer; current; solution; potential; resistance; composition; x-ray; ions; showed	Two copper-zinc (Cu-Zn) alloy wires with different copper contents (90Cu/10Zn and 65Cu/35Zn) were used as sacrificed electrodes in submerged arc discharge process at ambient pressure. Three types of dielectric liquids including ethylene glycol, ethanol and deionized water were investigated. The microstructure, composition and size of the particles obtained were examined by high-resolution transmission electron microscopy with energy dispersive X-ray spectroscopy (TEM/EDS) and X-ray diffraction (XRD) analysis. The particles synthesized from both wires in all dielectric liquids were spherical with size in the range of 5-50 nm. Ethylene glycol yielded the smallest particles, in comparison deionized water yielded the largest particles. These particles contained Cu, Cu-Zn, and zinc oxide without copper oxide. L-Ascorbic acid was then used as a reducing agent to eliminate zinc oxide. Thus, the 5-50nm spherical Cu/Cu-Zn nanoparticles with similar composition to the wires used, can be synthesized. However, ethanol cannot be used as dielectric liquid in case of 65Cu/35Zn wire, because high zinc content in ethanol with L-ascorbic acid formed zinc oxalate. Conductive ink was prepared from the particles synthesized by using 90Cu/10Zn in ethylene glycol, and screen printed on poly(ethylene terephthalate) (PET) substrate. The patterns printed could be sintered in air at 150 degrees C for 60 min. The patterns fabricated were characterized by scanning electron microscope with energy dispersive X-ray spectroscopy (SEM/EDS). The resistivity of the conductive pattern was measured by two-point probe at room temperature. The lowest volume resistivity of the pattern obtained was 125 mu Omega cm. (C) 2014 The Japan Society of Applied Physics
10.7567-JJAP.55.06JB01	2	corrosion; surface; film; electrochemical; films; spectroscopy; layer; current; solution; potential; resistance; composition; x-ray; ions; showed	Benzotriazole (BTA) has been used to protect copper (Cu) from corrosion during Cu chemical mechanical planarization (CMP) processes. However, an undesirable Cu-BTA complex is deposited after Cu CMP processes and it should be completely removed at post-Cu CMP cleaning for next fabrication process. Therefore, it is very important to understand of Cu-BTA complex formation behavior for its applications such as Cu CMP and post-Cu CMP cleaning. The present study investigated the effect of pH and polisher conditions on the formation of Cu-BTA complex layers using electrochemical techniques (potentiodynamic polarization and electrochemical impedance spectroscopy) and the surface contact angle. The wettability was not a significant factor for the polishing interface, as no difference in the contact angles was observed for these processes. Both electrochemical techniques revealed that BTA had a unique advantage of long-term protection for Cu corrosion in an acidic condition (pH 3). (C) 2016 The Japan Society of Applied Physics
10.7567-JJAP.56.07KD03	-1		Sea urchin-shaped hybrid copper powder (HCuP), which is characterized by copper alloy powder particles covered with vertically aligned Co-catalyzed carbon nanofibers (CNFs), was successfully synthesized to improve the oxidation resistance of copper paste. Fine spherical CuCo alloy particles with nominal composition of Cu/Co = 99/1w/w were fabricated by atomization. Cobalt nanoprecipitates (CoNPs) used as the catalyst for carbon fiber growth were arranged on the surface of an alloy particle by heat treatment. CNFs were grown from the CoNPs on the alloy particle via thermal chemical vapor deposition (CVD). The conductive paste was prepared by milling using HCuP with resin and oleic acid. HCuP paste was screen-printed on a glass or plastic substrate and showed a resistivity as low as 1.2 x 10(-4) Omega.cm after curing at 150 degrees C for 30 min in air (21% oxygen). These results indicate that the use of HCuP is a promising technology for printable electronics in a sustainable society. (C) 2017 The Japan Society of Applied Physics
10.7567-JJAPS.39S1.310	-1		Lattice vibration behaviors of defect stannite phases in the Cu-(In,Ga)-Se system are studied by the Raman spectrometry and the dispersion curve calculation in comparison with the chalcopyrite phases in this system. Bulk crystals in the alloy systems of Cu(In1-xGax)(3)Se-5 and Cu-2(In1-xGax)(4)Se-7 are prepared by the normal freezing method. The characteristic two Raman peaks at 160 and 175 cm(-1) for these crystals, apparently unrelated to the indium to gallium ratio, are assigned as two Fl modes of D-2d symmetry. This can be explained from the dispersion curve calculation assuming the vacancies at 2 alpha or 2b site of the defect stannite structure through the Cu-(In,Ga)-Se system.