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2017-10-19
Composition-dependent magnetic response properties of Mn$_{1-x}$Fe$_x$Ge alloys
The composition-dependent behavior of the Dzyaloshinskii-Moriya interaction (DMI), the spin-orbit torque (SOT), as well as anomalous and spin Hall conductivities of Mn$_{1-x}$Fe$_x$Ge alloys have been investigated by first-principles calculations using the relativistic multiple scattering Korringa-Kohn-Rostoker (KKR) f...
1710.07248v1
2018-04-28
Study of the elastocaloric effect and mechanical behavior for the NiTi shape memory alloys
The NiTi shape memory alloy exhibited excellent superelastic property and elastocaloric effect. Large temperature changes of 30 K upon loading and -19 K upon unloading were obtained at room temperature, which were higher than those of the other NiTi-based materials and among the highest values reported in the elastocal...
1804.10724v1
2019-03-04
Determining the Optimal Phase-Change Material via High-Throughput Calculations
The discovery and optimization of phase-change and shape memory alloys remain a tedious and expensive process. Here a simple computational method is proposed to determine the ideal phase-change material for a given alloy composed of three elements. Using first-principles calculations, within a high-throughput framework...
1903.01286v1
2019-03-11
The Paracrystalline Nature of Lattice Distortion in a High Entropy Alloy
Severe lattice distortion is suggested for high entropy alloys (HEAs), however, evidence for such effect so far is lacking, and the nature of distortion is yet to be understood. Here, we reveal the distortion in an fcc HEA, Al0.1CrFeCoNi, by direct imaging using electron nanodiffraction. Information about crystal symme...
1903.04082v1
2019-05-06
An electrically tunable terahertz plasmonic device based on shape memory alloys and liquid metals
An electrically tunable terahertz (THz) plasmonic device is designed and fabricated using liquid metals (eutectic gallium indium EGaIn) and shape memory alloy wires (Flexinol). The liquid metal is injected into the voids of a poly(dimethyl) siloxane (PDMS) microfluidic mold forming a periodic array of subwavelength ape...
1905.01837v1
2019-05-18
The New Nitrides: Layered, Ferroelectric, Magnetic, Metallic and Superconducting Nitrides to Boost the GaN Photonics and Electronics Eco-System
The nitride semiconductor materials GaN, AlN, and InN, and their alloys and heterostructures have been investigated extensively in the last 3 decades, leading to several technologically successful photonic and electronic devices. Just over the past few years, a number of new nitride materials have emerged with exciting...
1905.07627v1
2019-08-01
The effect of thermal history on the atomic structure and mechanical properties of amorphous alloys
The influence of thermal processing on the potential energy, atomic structure, and mechanical properties of metallic glasses is examined using molecular dynamics simulations. We study the three-dimensional binary mixture, which was first relaxed near the glass transition temperature, and then rapidly cooled deep into t...
1908.00464v1
2019-08-14
Uncharacteristic second order martensitic transformation in metals via epitaxial stress fields
While most phase transformations, e.g. ferroelectric or ferromagnetic, can be first or second order depending on external applied fields, martensitic transformations in metallic alloys are nearly universally first order. We demonstrate that epitaxial stress originating from the incorporation of a tailored second phase ...
1908.05342v2
2019-08-30
Magnetization reversal, damping properties and magnetic anisotropy of L10-ordered FeNi thin films
L10 ordered magnetic alloys such as FePt, FePd, CoPt and FeNi are well known for their large magnetocrystalline anisotropy. Among these, L10-FeNi alloy is economically viable material for magnetic recording media because it does not contain rare earth and noble elements. In this work, L10-FeNi films with three differen...
1908.11761v1
2019-09-12
Electronic Structure Calculation of AsSiTeB/SiAsBTe nanostructures using the Density Functional Theory
The electronic structure calculation for the nanoclusters of (AsSiTeB/SiAsBTe) quaternary semiconductor alloy belonging to the (III-V Group elements) is performed. The two clusters one in the linear form and the other in the bent form have been studied under the framework of Density Functional Theory (DFT) using the B3...
1909.05799v1
2019-09-13
CuAu, a hexagonal two-dimensional metal
Growth of two-dimensional metals has eluded materials scientists since the discovery of the atomically thin graphene and other covalently bound 2D materials. Here, we report a two-atom-thick hexagonal copper-gold alloy, grown through thermal evaporation on freestanding graphene and hexagonal boron nitride. The structur...
1909.06372v5
2019-09-18
Application-oriented strain-hardening engineering of high-manganese steels
The outstanding mechanical properties of high-manganese steels (HMnS) are a result of their high strain-hardenability. That is facilitated by strong suppression of dynamic recovery, predominant planar glide, and the activation of additional deformation mechanisms, such as transformation-induced plasticity (TRIP) and tw...
1909.08677v1
2019-09-20
3D characterization of the primary Al3Sc phases in an Al-Sc alloy using Synchrotron X-ray tomography and electron microscopy
The three-dimensional structures of the primary Al3Sc particles in an Al-2Sc master alloy were studied by synchrotron X-ray microtomography, scanning and transmission electron microscopy. The Al3Sc phases were found to be a single cube and a cluster of cubes. The surface area, equivalent diameter of the Al3Sc cubes inc...
1909.09388v1
2019-09-26
Universal Characterization of Hierarchical Ordering Tendency in High-Entropy Alloys from Configurational Geometry
Microscopic structures for fcc-based quaternary high-entropy alloys (HEA) in thermodynamically equilibrium state is examined based on first-principles (FP) calculation combined with our recently-developed theoretical approach. We find that (i) hierarchical ordering tendency for whole quaternary, and ternary and binary ...
1909.11933v1
2019-09-30
Amorphous intergranular films mitigate radiation damage in nanocrystalline Cu-Zr
Nanocrystalline metals are promising radiation tolerant materials due to their large interfacial volume fraction, but irradiation-induced grain growth can eventually degrade any improvement in radiation tolerance. Therefore, methods to limit grain growth and simultaneously improve the radiation tolerance of nanocrystal...
1909.13436v2
2019-09-30
The effect of surface preparation on high temperature oxidation of Ni, Cu and Ni-Cu alloy
In the present paper, the analysis of polishing, grinding and sand-blasting processes on oxidation behavior of nickel, copper and nickel-copper alloy has been investigated. Surface roughness has been measured using two methods: by contact profilometer and by fractal analysis. It has been proved that sand-blasting proce...
1909.13659v2
2019-12-04
Complex Strengthening Mechanisms in the NbMoTaW Multi-Principal Element Alloy
Refractory multi-principal element alloys (MPEAs) have exceptional mechanical properties, including high strength-to-weight ratio and fracture toughness, at high temperatures. Here, we elucidate the complex interplay between segregation, short range order and strengthening in the NbMoTaW MPEA through atomistic simulati...
1912.01789v3
2019-12-03
Geometry of martensite needles in shape memory alloys
We study the geometry of needle-shaped domains in shape-memory alloys. Needle-shaped domains are ubiquitously found in martensites around macroscopic interfaces between regions which are laminated in different directions, or close to macroscopic austenite/twinned-martensite interfaces. Their geometry results from the i...
1912.02274v1
2019-12-08
Thermoelectric properties of Half-Metallic FeMnScGa Using First Principle Calculation
Here, we have investigated the thermoelectric properties of FeMnScGa alloy by combined use of full potential linearized augmented plane-wave (FP-LAPW) method and Boltzmann transport theory implemented in Wien2K and BoltzTraP code, respectively. Using the TB-mBJ potential, half-metallic nature is clearly observed with e...
1912.03709v1
2019-12-14
The Controlled Large-Area Synthesis of Two Dimensional Metals
The rise of nanotechnology has been propelled by low dimensional metals. Albeit the long perceived importance, synthesis of freestanding metallic nanomembranes, or the so-called 2D metals, however has been restricted to simple metals with a very limited in-plane size (< 10{\mu}m). In this work, we developed a low-cost ...
1912.06826v1
2020-02-02
Effect of Al content on the critical resolved shear stress for twin nucleation and growth in Mg alloys
The effect of Al atoms in solid solution on the critical resolved shear stress for twin nucleation and growth was analyzed by means of the combination of diffusion couples with compression tests in micropillars oriented for twinning. The critical resolved shear stress for twin nucleation was higher than that for twin g...
2002.00385v1
2020-02-04
Non-contact, non-destructive mapping of thermal diffusivity and surface acoustic wave speed using transient grating spectroscopy
We present new developments of the laser-induced transient grating spectroscopy (TGS) technique that enable the measurement of large area 2D maps of thermal diffusivity and surface acoustic wave speed. Additional capabilities include targeted measurements and the ability to accommodate samples with increased surface ro...
2002.01409v1
2020-02-04
Blocking of martensitic transition at the nano-scale in the Ti2NiCu wedge
Shape memory effect associated with martensitic transformations is of the rapidly developing field in nanotechnologies, where industrial use of systems established on that effect provide greater flexibility on the nano-devices fabrication of various kind. And therefore it addresses questions to the phase transition phe...
2002.07132v1
2020-03-02
Short range order and topology of Ge$_{x}$Ga$_{x}$Te$_{100-2x}$ glasses
Chemical short range order and topology of Ge$_{x}$Ga$_{x}$Te$_{100-2x}$ glasses was investigated by neutron- and x-ray diffraction as well as Ge and Ga K-edge extended x-ray absorption fine structure (EXAFS) measurements. Large scale structural models were obtained by fitting experimental datasets simultaneously with ...
2003.00772v2
2020-03-02
Calculation of Optical Response Functions of Dilute-N GaPAsN Lattice-matched to Si
Dilute-N GaPAsN alloys have great potential for optoelectronics lattice-matched to Si. However, there is a lack of systematic calculation of the optical response of these alloys. The present paper uses the sp^3d^5s^*s_N tight-binding model to calculate the fullband electronic structure of dilute-N GaPAsN, and then calc...
2003.01143v1
2020-03-04
Machine Learning of Mechanical Properties of Steels
The mechanical properties are essential for structural materials. The analyzed 360 data on four mechanical properties of steels, viz. fatigue strength, tensile strength, fracture strength, and hardness, are selected from the NIMS database, including carbon steels, and low-alloy steels. Five machine learning algorithms ...
2003.01943v2
2020-03-10
CdO/MgO superlattices grown by MBE as cubic CdMgO quasi-alloys
New perspective cubic quasi-alloys CdO/MgO short period superlattices were grown on sapphire substrates by plasma assisted molecular beam epitaxy. Their crystal quality was characterized using High Resolution X-ray Diffraction (HRXRD) and Transmission Electron Microscopy (TEM) techniques. The thickness and growth rate ...
2003.04704v1
2020-03-18
Superconductivity in hexagonal Nb-Mo-Ru-Rh-Pd high-entropy alloys
We report the superconducting properties of new hexagonal Nb$_{10+2x}$Mo$_{35-x}$Ru$_{35-x}$Rh$_{10}$Pd$_{10}$ high-entropy alloys (HEAs) (0 $\leq$ $x$ $\leq$ 5). With increasing $x$, the superconducting transition temperature $T_{\rm c}$ shows a maximum of 6.19 K at $x$ = 2.5, while the zero-temperature upper critical...
2003.08020v1
2020-03-19
Validation of secondary fluorescence excitation in quantitative X-ray fluorescence analysis of thin alloy films
X-ray fluorescence (XRF) analysis is a widely applied technique for the quantitative analysis of thin films up to the $\mu$m scale because of its non-destructive nature and because it is easily automated. When low uncertainties of the analytical results in the few percent range are required, the non-linear secondary fl...
2003.08930v1
2020-03-21
A Series of Plasma Innovation Technologies by Double Glow Discharge Phenomenon
In order to break the limitation of plasma nitriding technology,which can be applied to a few nonmetallic gaseous elements, the "Double Glow Discharge Phenomenon" was found and then invented the "Double Glow Plasma Surface Metallurgy Technology". This double glow plasma surface metallurgy technology can use any element...
2003.09770v1
2020-05-30
Multi-fidelity machine-learning with uncertainty quantification and Bayesian optimization for materials design: Application to ternary random alloys
We present a scale-bridging approach based on a multi-fidelity (MF) machine-learning (ML) framework leveraging Gaussian processes (GP) to fuse atomistic computational model predictions across multiple levels of fidelity. Through the posterior variance of the MFGP, our framework naturally enables uncertainty quantificat...
2006.00139v3
2020-06-02
A high entropy alloy as very low melting point solder for advanced electronic packaging
SnBiInZn based high entropy alloy (HEA) was studied as a low reflow temperature solder with melting point around 80 oC. The wetting angle is about 52o after reflow at 100 oC for 10 min. The interfacial intermetallic compound (IMC) growth kinetics was measured to be ripening-control with a low activation energy about 18...
2006.01345v1
2020-06-10
Positive versus negative resistance response to hydrogenation in palladium and its alloys
Resistive solid state sensors are widely used in multiple applications, including molecular and gas detection. Absorption or intercalation of the target species varies the lattice parameters and an effective thickness of thin films, which is usually neglected in analyzing their transport properties in general and the s...
2006.05801v1
2020-06-16
An averaged cluster approach to including chemical short range order in KKR-CPA
The single-site Korringa-Kohn-Rostoker Coherent Potential Approximation (KKR-CPA) ignores short range ordering present in disordered metallic systems. In this paper, we establish a new technique to fix this shortcoming by embedding an averaged cluster that displays chemical short range order (SRO). The degree of SRO ca...
2006.09421v3
2020-06-27
Embracing the chaos: Alloying adds stochasticity to twin embryo growth
High-throughput atomistic simulations reveal the unique effect of solute atoms on twin variant selection in Mg-Al alloys. Twin embryos first undergo a stochastic incubation stage when embryos choose which twin variant to adopt, and then a deterministic growth stage when embryos expand without changing the selected twin...
2006.15242v4
2020-07-04
High Entropy Alloys as a new metaphor in sociophysics
Most of the opinion dynamics models in sociophysics have their historic origin in studies two-dimensional magnetization phenomena. This metaphor has proven quite useful, as it allowed to use well known techniques, relating individual behaviours of single spins and their interactions, to large scale properties, such as ...
2007.02154v1
2020-07-18
Performance Analysis of Metaheuristic Optimization Algorithms in Estimating the Interfacial Heat Transfer Coefficient on Directional Solidification
In this paper is proposed an evaluation of ten metaheuristic optimization algorithms applied on the inverse optimization of the Interfacial Heat Transfer Coefficient (IHTC) coupled on the solidification phenomenon. It was considered an upward directional solidification system for Al-7wt.% Si alloy and, for IHTC model, ...
2007.15583v1
2020-09-02
Quantitative precipitate classification and grain boundary property control in Co/Ni-base superalloys
A correlative approach is employed to simultaneously assess structure and chemistry of (carbide and boride) precipitates in a set of novel Co/Ni-base superalloys. Structure is derived from electron backscatter diffraction (EBSD) with pattern template matching, and chemistry obtained with energy dispersive X-ray spectro...
2009.00948v1
2020-09-08
High-Pressure Torsion Deformation Induced Phase Transformations and Formations: New Material Combinations and Advanced Properties
Heavy plastic shear deformation at relatively low homologous temperatures is called high-pressure torsion (HPT) deformation, which is one method of severe plastic deformation (SPD). The aim of the paper is to give an overview of a new processing approach which permits the generation of innovative metastable materials a...
2009.03531v1
2020-09-10
Quantifying the effect of oxygen on micro-mechanical properties of a near-alpha titanium alloy
Atom probe tomography (APT), electron probe microanalysis (EPMA) and nanoindentation were used to characterise the oxygen-rich layer on an in-service jet engine compressor disc, manufactured from the titanium alloy TIMETAL 834. Oxygen ingress was quantified and related to changes in mechanical properties through nanoin...
2009.04959v1
2020-09-16
Superconductivity in CuAl2-type Co0.2Ni0.1Cu0.1Rh0.3Ir0.3Zr2 with a high-entropy-alloy transition metal site
Research on high-entropy-alloy (HEA) superconductors is a growing field in material science. In this study, we explored new HEA-type superconductors and discovered a CuAl2-type superconductor Co0.2Ni0.1Cu0.1Rh0.3Ir0.3Zr2 with a HEA-type transition metal site. A superconducting transition was observed at 8.0 K after ele...
2009.07548v3
2020-09-18
Synthesis of epitaxial monolayer Janus SPtSe
Janus single-layer transition metal dichalcogenides, in which the two chalcogen layers have a different chemical nature, push chemical composition control beyond what is usually achievable with van der Waals heterostructures. Here we report such a novel Janus compound, SPtSe, which is predicted to exhibit strong Rashba...
2009.08706v1
2020-09-23
Partial Order-Disorder Transition Driving Closure of Band Gap: Example of Thermoelectric Clathrates
On the quest for efficient thermoelectrics, semiconducting behavior is a targeted property. Yet, this is often difficult to achieve due to the complex interplay between electronic structure, temperature, and disorder. We find this to be the case for the thermoelectric clathrate Ba$_8$Al$_{16}$Si$_{30}$: Although this m...
2009.11137v1
2020-09-25
Predicting activation energies for vacancy-mediated diffusion in alloys using a transition-state cluster expansion
Kinetic Monte Carlo models parameterized by first principles calculations are widely used to simulate atomic diffusion. However, accurately predicting the activation energies for diffusion in substitutional alloys remains challenging due to the wide variety of local environments that may exist around the diffusing atom...
2009.12474v3
2020-09-27
Transition from band insulator to excitonic insulator via alloying Se into Monolayer TiS$_3$: A Computational Study
First-principles density functional theory plus Bethe-Salpeter equation calculations are employed to investigate the electronic and excitonic properties of monolayer titanium trichalcogenide alloys TiS$_{3-x}$Se$_x$ ($x$=1 and 2). It is found that bandgap and exciton binding energy display asymmetric dependence on the ...
2009.12805v1
2020-10-02
Band structure and topological phases of Pb$_{1-x-y}$Sn$_x$Mn$_y$Te by ab initio calculations
The change in the composition of Pb$_{1-x}$Sn$_x$Te IV-VI semiconductor or in its lattice parameter can drive a transition from the topologically trivial to the topological crystalline insulator (TCI), crossing a region where the alloy is in the Weyl semimetal phase. Incorporation of the magnetic Mn ions induces strong...
2010.00874v1
2020-10-13
Effects of spin-orbit torque on the ferromagnetic and exchange spin wave modes in ferrimagnetic CoGd alloy
We use micro-focus Brillouin light scattering spectroscopy to study the effects of spin-orbit torque on thermal spin waves in almost angular-momentum compensated ferrimagnetic CoGd alloy films. The spin-orbit torque is produced by the electric current flowing in the Pt layer adjacent to CoGd. Both the ferromagnetic and...
2010.06615v1
2020-10-25
Directed long-range transport of a nearly pure component atom clusters by the electromigration of a binary surface alloy
Assuming a vacancy-mediated diffusion, a continuum model for electromigration-driven transport of an embedded atom cluster across a surface terrace of a phase-separating A$_x$B$_{1-x}$ surface alloy, such as fcc AgPt(111), is presented. Computations show that the electron wind carries the cluster over hundreds of latti...
2010.13144v3
2020-10-27
MeltNet: Predicting alloy melting temperature by machine learning
Thermodynamics is fundamental for understanding and synthesizing multi-component materials, while efficient and accurate prediction of it still remain urgent and challenging. As a demonstration of the "Divide and conquer" strategy decomposing a phase diagram into different learnable features, quantitative prediction of...
2010.14048v1
2020-10-28
Nanowire design by magnetic collection of Fe, Ni and/or FeNi-alloy nanoparticles
A method for growing nanoparticles with different elemental compositions simply by changing pulsing parameters in a power supply is demonstrated. The technique is based on high power pulsed hollow cathode sputtering, and the difference in particle composition ranges from pure Fe and Ni, to fully alloyed FeNi particles....
2010.15013v1
2020-11-08
Finite-temperature materials modeling from the quantum nuclei to the hot electrons regime
Atomistic simulations provide insights into structure-property relations on an atomic size and length scale, that are complementary to the macroscopic observables that can be obtained from experiments. Quantitative predictions, however, are usually hindered by the need to strike a balance between the accuracy of the ca...
2011.03874v1
2020-11-11
Synthesis of high-entropy-alloy-type superconductors (Fe,Co,Ni,Rh,Ir)Zr2 with tunable transition temperature
We report on the synthesis and superconductivity of high-entropy-alloy-type (HEA-type) compounds TrZr2 (Tr = Fe, Co, Ni, Rh, Ir), in which the Tr site satisfies the criterion of HEA. Polycrystalline samples of HEA-type TrZr2 with four different compositions at the Tr site were synthesized by arc melting method. The pha...
2011.05590v1
2020-11-11
Exploring the transfer of plasticity across Laves phase interfaces in a dual phase magnesium alloy
The mechanical behaviour of Mg-Al alloys can be largely improved by the formation of an intermetallic Laves phase skeleton, in particular the creep strength. Recent nanomechanical studies revealed plasticity by dislocation glide in the (Mg,Al)$_2$Ca Laves phase, even at room temperature. As strengthening skeleton, this...
2011.05852v4
2020-11-13
Interdependent linear complexion structure and dislocation mechanics in Fe-Ni
Using large-scale atomistic simulations, dislocation mechanics in the presence of linear complexions are investigated in an Fe-Ni alloy, where the complexions appear as nanoparticle arrays along edge dislocation lines. When mechanical shear stress is applied to drive dislocation motion, a strong pinning effect is obser...
2011.07148v2
2020-11-17
Effect of Substrate Roughness on Oxidation Resistance of an Aluminized Ni-Base Superalloy
In the present work, it is shown that the surface preparation method used on two Ni-based superalloys prior to aluminizing chemical vapor deposition (CVD) is one of the most important factors determining the oxidation resistance of aluminized Ni-based superalloys. It was found that grit blasting the substrate surface n...
2011.08921v1
2020-11-25
Growth of germanium-silver surface alloys followed by in situ scanning tunneling microscopy: Absence of germanene formation
Theoretical studies have shown that new physical properties such as tunable gap openings or quantum spinHall effects could be expected from group-IV graphene analogs (silicene, germanene, stanene). While therehave been numerous studies of growth of such Si, Ge, Sn monolayers, the demonstration of their hexagonalorganiz...
2011.12577v1
2020-11-25
Enhancement of giant refrigerant capacity in Ho$_{1-x}$Gd$_{x}$B$_{2}$ alloys (0.1 $\leq$ x $\leq$ 0.4)
Intending to optimize the giant magnetocaloric properties of HoB$_{2}$, we synthesized and magnetocalorically characterized Ho$_{1-x}$Gd$_{x}$B$_{2}$(0.1 $\leq$ x $\leq$ 0.4) alloys. We found out that Gd enters stoichiometrically and randomly into the Ho site, leading to a Vegard-type structural change. The addition of...
2011.12660v1
2020-11-27
Spectral quadrature for the first principles study of crystal defects: Application to magnesium
We present an accurate and efficient finite-difference formulation and parallel implementation of Kohn-Sham Density (Operator) Functional Theory (DFT) for non periodic systems embedded in a bulk environment. Specifically, employing non-local pseudopotentials, local reformulation of electrostatics, and truncation of the...
2011.13517v1
2020-11-27
Recrystallization Characteristics of Catalytic Alloy and Graphite in Diamond Synthesis
We first consider the recrystallization characteristics of catalysis alloy and graphite in the process of diamond synthesis under the condition of super high pressure and high temperature in catalysis method. In the process of diamond synthesis catalysis metal is plastically deformed by increase of pressure and then re...
2011.13827v1
2020-11-29
Visualizing Temperature-Dependent Phase Stability in High Entropy Alloys
High Entropy Alloys (HEAs) contain near equimolar amounts of five or more elements and are a compelling space for materials design. Great emphasis is placed on identifying HEAs that form a homogeneous solid-solution, but the design of such HEAs is hindered by the difficulty of navigating stability relationships in high...
2011.14446v2
2020-12-24
A non-local model for the description of twinning in polycrystalline materials in the context of infinitesimal strains: application to a magnesium alloy
A polycrystalline plasticity model, which incorporates the contribution of deformation twinning, is proposed. For this purpose, each material point is treated as a composite material consisting of a parent constituent and multiple twin variants. In the constitutive equations, the twin volume fractions and their spatial...
2012.13156v6
2020-12-29
Lattice stability of ordered Au-Cu alloys in the warm dense matter regime
In the warm dense regime, where the electron temperature is increased to the same order of the Fermi temperature, the dynamical stability of elemental metals depends on its electronic band structure as well as its crystal structure. It has been known that phonon hardening occurs due to an enhanced internal pressure cau...
2012.14537v2
2021-01-04
Unraveling the optical contrast in Sb2Te and AgInSbTe phase-change materials
Chalcogenide phase-change materials (PCMs) show a significant contrast in optical reflectivity and electrical resistivity upon crystallization from the amorphous phase and are leading candidates for non-volatile photonic and electronic applications. In addition to the flagship Ge2Sb2Te5 phase-change alloy, doped Sb2Te ...
2101.00789v2
2021-01-07
Mechanisms behind large Gilbert damping anisotropies
A method with which to calculate the Gilbert damping parameter from a real-space electronic structure method is reported here. The anisotropy of the Gilbert damping with respect to the magnetic moment direction and local chemical environment is calculated for bulk and surfaces of Fe$_{50}$Co$_{50}$ alloys from first pr...
2101.02794v2
2021-01-08
Mössbauer Spectroscopic and XRD Studies of two eta-Fe2Al5 Intermetallics
Two intermetallic FeAl compounds with Al content of 70.68 and 72.17 at.pct were studied using M\"ossbauer spectroscopy (5 to 296 K) and X-ray diffraction (15 to 300 K). The compounds were found to crystallize in the orthorhombic Cmcm space group (eta-phase). The collected data revealed that dynamics of the Fe atoms (ha...
2101.03158v1
2021-01-18
Double band inversion in the topological phase transition of Ge1-xSnx alloys
We use first-principles simulation and virtual crystal approximation to reveal the unique double band inversion and topological phase transition in Ge1-xSnx alloys. Wavefunction parity, spatial charge distribution and surface state spectrum analyses suggest that the band inversion in Ge1-xSnx is relayed by its first va...
2101.06929v1
2021-02-02
Superconductivity in HEA-type compounds
Since the discovery of superconductivity in a high-entropy alloy (HEA) Ti-Zr-Nb-Hf-Ta in 2014, the community of superconductor science has explored new HEA superconductors to find the merit of the HEA states on superconducting properties. Since 2018, we have developed HEA-type compounds as superconductors or thermoelec...
2102.01321v1
2021-02-03
Evolutionary search for cobalt-rich compounds in the yttrium-cobalt-boron system
Modern high-performance permanent magnets are made from alloys of rare earth and transition metal elements, and large magnetization is achieved in the alloys with high concentration of transition metals. We applied evolutionary search scheme based on first-principles calculations to the Y-Co-B system and predicted 37 c...
2102.02097v1
2021-02-04
Ultrafast scattering dynamics of coherent phonons in Bi$_{1-x}$Sb$_{x}$ in the Weyl semimetal phase
We investigate ultrafast phonon dynamics in the Bi$_{1-x}$Sb$_{x}$ alloy system for various compositions $x$ using a reflective femtosecond pump-probe technique. The coherent optical phonons corresponding to the A$_{1g}$ local vibrational modes of Bi-Bi, Bi-Sb, and Sb-Sb are generated and observed in the time domain wi...
2102.02397v1
2021-02-05
Correlative statistical microstructural assessment of precipitates and their distribution, with simultaneous electron backscatter diffraction and energy dispersive X-ray spectroscopy
Modern engineering alloys have bespoke microstructures, where features such as precipitates are used to control properties. In many Ni-based alloys, carbo-nitride precipitates are introduced to strengthen and improve performance. These precipitates can be distributed throughout the microstructure and niobium rich carbi...
2102.03279v2
2021-02-11
High-Throughput Rapid Experimental Alloy Development (HT-READ)
The current bulk materials discovery cycle has several inefficiencies from initial computational predictions through fabrication and analyses. Materials are generally evaluated in a singular fashion, relying largely on human-driven compositional choices and analysis of the volumes of generated data, thus also slowing v...
2102.06180v1
2021-02-13
Charge-transfer effect on local lattice distortion in a HfNbTiZr high entropy alloy
It is often assumed that atoms are hard spheres in the estimation of local lattice distortion (LLD) in high-entropy alloys (HEAs). However, our study demonstrates that the hard sphere model misses the key effect, charge transfer among atoms with different electronegativities, in the understanding of the stabilization o...
2102.06906v2
2021-02-17
Modification of the quasi-lattice theory for liquid alloys on the basis of varying the coordination number and its application to Al-Sn, Al-Zn and Sn-Zn
The existing quasi-lattice theory for liquid alloys (QLT), which has been extensively used by many researchers, has been modified by incorporating the knowledge of composition and temperature-dependent coordination numbers. The modified QLT was then used to compute the enthalpy of mixing, the entropy of mixing, concent...
2102.08516v1
2021-02-19
Local Observations of Orbital Diamagnetism and Excitation in Three-Dimensional Dirac Fermion Systems Bi$_{1-x}$Sb$_x$
Dirac fermions display a singular response against magnetic and electric fields. A distinct manifestation is large diamagnetism originating in the interband effect of Bloch bands, as observed in bismuth alloys. Through $^{209}$Bi NMR spectroscopy, we extract diamagnetic orbital susceptibility inherent to Dirac fermions...
2102.09917v1
2021-02-22
Crossover between short and long range proximity effects in SFS junctions with Ni-based ferromagnets
We study Superconductor/Ferromagnet/Superconductor junctions with CuNi, PtNi, or Ni interlayers. Remarkably, we observe that supercurrents through Ni can be significantly larger than through diluted alloys. The phenomenon is attributed to the dirtiness of disordered alloys leading to a short coherence length despite a ...
2102.10927v1
2021-02-24
Synthesis of new high-entropy alloy-type Nb3 (Al, Sn, Ge, Ga, Si) superconductors
Studies on high-entropy alloy (HEA) superconductors have recently been increasing, particularly in the fields of materials science and condensed matter physics. To contribute to research on new HEA-type superconductors, in our study we synthesized polycrystalline samples of A15-type superconductors of Nb3Al0.2Sn0.2Ge0....
2102.12271v1
2021-02-25
Precursor of the premartensite in Ni2MnGa magnetic shape memory alloy: A pair distribution function study
Precursor phenomena observed prior to the martensite phase transition plays a critical role towards the understanding of important technological properties of shape memory and magnetic shape memory alloys (MSMAs). The premartensite (PM) phase, considered as the precursor state of the martensite is proven to be a thermo...
2102.13024v2
2021-02-25
Application of high-spatial-resolution secondary ion mass spectrometry for nanoscale chemical mapping of lithium in an Al-Li alloy
High-spatial-resolution secondary ion mass spectrometry offers a method for mapping lithium at nanoscale lateral resolution. Practical implementation of this technique offers significant potential for revealing the distribution of Li in many materials with exceptional lateral resolution and elemental sensitivity. Here,...
2102.13148v1
2021-02-25
Computation of infinite dilute activity coefficients for Ga-X (X= In, Tl) and thermodynamic activities of all components in liquid Ga-In-Tl alloys
The thermodynamic activities of all components in Ga-In-Tl system have been predicted at 1073, 1173 and 1273 K, using Molecular interaction volume model (MIVM). The infinite dilute activity coefficients for Ga-In and Ga-Tl binary subsystems, which were needed for the determination of thermodynamic activities of all com...
2102.13199v1
2021-04-02
Highly Complex Magnetic Structures Resulting From Hierarchical Phase Separation in AlCo(Cr)FeNi High Entropy Alloys
Magnetic high entropy alloys (HEAs) are a new category of high-performance magnetic materials, with multi-component concentrated compositions and complex multi-phase structures. Although there have been numerous reports of their interesting magnetic properties, there is very limited understanding about the interplay be...
2104.00943v1
2021-04-29
Parallel Projection---An Improved Return Mapping Algorithm for Finite Element Modeling of Shape Memory Alloys
We present a novel finite element analysis of inelastic structures containing Shape Memory Alloys (SMAs). Phenomenological constitutive models for SMAs lead to material nonlinearities, that require substantial computational effort to resolve. Finite element analysis methods, which rely on Gauss quadrature integration s...
2104.14424v2
2021-05-04
Microstructural and compositional design principles for Mo-V-Nb-Ti-Zr multi-principal element alloys: a high-throughput first-principles study
Due to the vast compositional space of multi-principal element alloys (MPEAs), the rational design of MPEAs for optimized microstructures is difficult. Therefore, a high-throughput first-principles study of Mo-V-Nb-Ti-Zr, a refractory MPEA, was conducted to gain insights into the underlying microstructures. Using Monte...
2105.01329v1
2021-05-08
Zr and Mo macrosegregation in Ti6246 titanium alloy industrial-scale ingot by vacuum arc remelting
Zr and Mo macrosegregations were investigated in Ti6246 titanium alloy industrial-scale ingotby vacuum arc remelting. The formation mechanism of Zr and Mo macrosegregations was studied during the solidification process. Zr macrosegregation was characterized by low content in the equiaxed grain zone and high content in ...
2105.03555v1
2021-05-11
Icosahedral quasicrystal-enhanced nucleation in Al alloys fabricated by selective laser melting
Selective laser melting (SLM) is rapidly evolving to become a mainstream technology. However, the fundamental mechanisms of solidification and microstructure development inherent to the non-equilibrium conditions of this additive manufacturing method, which differ largely from those typical of conventional processing t...
2105.05101v1
2021-05-14
Mechanical Response of Mesoporous Amorphous NiTi Alloy to External Deformations
The porous titanium nickelide is very popular in various industries due to unique combination of physical and mechanical properties such as shape memory effect, high corrosion resistance, and biocompatibility. The non-equilibrium molecular dynamics simulation was applied to study the influence of porosity degree on mec...
2105.06693v1
2021-05-14
Dynamical mean-field theory of the Anderson-Hubbard model with local and non-local disorder in tensor formulation
To explore correlated electrons in the presence of local and non-local disorder, the Blackman-Esterling-Berk method for averaging over off-diagonal disorder is implemented into dynamical mean-field theory using tensor notation. The impurity model combining disorder and correlations is solved using the recently develope...
2105.06971v1
2021-05-20
Coexistence of ferromagnetism and spin-orbit coupling by incorporation of platinum in two-dimensional VSe$_2$
We report on a novel material, namely two-dimensional (2D) V$_{1-x}$Pt$_x$Se$_2$ alloy, exhibiting simultaneously ferromagnetic order and Rashba spin-orbit coupling. While ferromagnetism is absent in 1T-VSe$_2$ due to the competition with the charge density wave phase, we demonstrate theoretically and experimentally th...
2105.10022v1
2021-05-26
Phase Separation and Anomalous Volume Expansion in Frozen Microscale Eutectic Indium-Gallium upon Remelting
The eutectic Ga-In (EGaIn) alloy has low vapor pressure, low toxicity, high thermal and electrical conductivities, and thus has shown a great potential for smart material applications. For such applications, EGaIn is maintained above its melting point, below which it undergoes solidification and phase separation. A sci...
2105.12799v2
2021-05-26
Interatomic Fe-Cr potential for modeling kinetics on Fe surfaces
To enable accurate molecular dynamics simulations of iron-chromium alloys with surfaces, we develop, based on density-functional-theory (DFT) calculations, a new interatomic Fe-Cr potential in the Tersoff formalism. Contrary to previous potential models, which have been designed for bulk Fe-Cr, we extend our potential ...
2105.12859v1
2021-05-27
Full band Monte Carlo simulation of AlInAsSb digital alloys
Avalanche photodiodes fabricated from AlInAsSb grown as a digital alloy exhibit low excess noise. In this paper, we investigate the band structure-related mechanisms that influence impact ionization. Band-structures calculated using an empirical tight-binding method and Monte Carlo simulations reveal that the mini-gaps...
2105.13176v1
2021-06-02
Growth and characterization of quaternary-alloy ferromagnetic semiconductor (In,Ga,Fe)Sb
We study the growth and properties of quaternary-alloy ferromagnetic semiconductor (FMS) (In0.94-x,Gax,Fe0.06)Sb (x = 5% - 30%, Fe concentration is fixed at 6%) grown by low temperature molecular beam epitaxy (LT-MBE).Reflection high-energy electron diffraction (RHEED) patterns, scanning transmission electron microscop...
2106.00938v1
2021-06-12
RF surface resistance tuning of superconducting niobium via thermal diffusion of native oxide
Recently, Nb superconducting radio frequency cavities vacuum heat treated between 300-400 C for a few hours have exhibited very high quality factors (~5x10^10 at 2.0 K). New secondary ion mass spectrometry measurements of O, N and C show this enhancement in RF surface conductivity is primarily associated with interstit...
2106.06647v2
2021-06-15
First-principles calculations on the spin anomalous Hall effect of ferromagnetic alloys
The spin anomalous Hall effect (SAHE) in ferromagnetic metals, which can generate spin-orbit torque to rotate the magnetization of another ferromagnetic layer through a non-magnetic spacer in magnetic junctions, has attracted much attention. We theoretically investigated the spin anomalous Hall conductivity (SAHC) of t...
2106.07993v2
2021-06-16
Combinatorial materials discovery strategy for high entropy alloy electrocatalysts using deposition source permutations
High entropy alloys offer a huge search space for new electrocatalysts. Searching for a global property maximum in one quinary system could require, depending on compositional resolution, the synthesis of up to 10E6 samples which is impossible using conventional approaches. Co-sputtered materials libraries address this...
2106.08776v1
2021-08-19
Molecular simulation-derived features for machine learning predictions of metal glass forming ability
We have developed models of metallic alloy glass forming ability based on newly computationally accessible features obtained from molecular dynamics simulations. In this work we showed that it is possible to increase the predictive value of GFA models by using input features obtained from molecular dynamics simulations...
2108.08766v1
2021-08-23
Orientation-related twinning and dislocation glide in a Cantor High Entropy Alloy at room and cryogenic temperature studied by in situ TEM straining
In situ straining experiments were performed in a TEM on an equimolar CoCrFeMnNi (Cantor) high entropy alloy at room and cryogenic temperature. Perfect and partial dislocation activity were recorded in both cases. Twinning directly follows the development of partial dislocation shearing that has various origins (perfec...
2108.10010v1
2021-08-12
Process parameter optimization of Friction Stir Welding on 6061AA using Supervised Machine Learning Regression-based Algorithms
The highest strength-to-weight ratio criterion has fascinated curiosity increasingly in virtually all areas where heft reduction is indispensable. Lightweight materials and their joining processes are also a recent point of research demands in the manufacturing industries. Friction Stir Welding (FSW) is one of the rece...
2109.00570v1
2021-09-05
Work Function Trends and New Low Work Function Boride and Nitride Materials for Electron Emission Applications
LaB6 has been used as a commercial electron emitter for decades. Despite the large number of studies on the work function of LaB6, there is no comprehensive understanding of work function trends in the hexaboride materials family. In this study, we use Density Functional Theory (DFT) calculations to calculated trends o...
2109.02004v1
2021-09-07
Probing the superconducting ground state of noncentrosymmetric high entropy alloys using muon-spin rotation and relaxation
Recently, high entropy alloys (HEAs) have emerged as a new platform for discovering superconducting materials and offer avenues to explore exotic superconductivity. The highly disordered nature of HEA suggests regular phonon required for BCS superconductivity may be unlikely to occur. Therefore understanding the micros...
2109.03368v1
2021-09-13
Gradient soft magnetic materials produced by additive manufacturing from non-magnetic powders
Additive manufacturing (AM) allows printing parts of complex geometries that cannot be produced by standard technologies. Besides, AM provides the possibility to create gradient materials with different structural and physical properties. We, for the first time, printed gradient soft magnetic materials from paramagneti...
2109.05947v1