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2016-07-28
Simulated spatial and temporal dependence of chromium concentration in pure Fe and Fe-14%Cr under high dpa ion irradiation
In this work we develop an ab initio informed rate theory model to track the spatial and temporal evolution of implanted ions (Cr+) in Fe and Fe-14%Cr during high dose irradiation. We focus on the influence of the specimen surface, the depth dependence of ion-induced damage, the damage rate, and the consequences of ion...
1607.08509v1
2016-08-10
Prediction of tool-wear in turning of medical grade cobalt chromium molybdenum alloy (ASTM F75) using non-parametric Bayesian models
We present a novel approach to estimating the effect of control parameters on tool wear rates and related changes in the three force components in turning of medical grade Co-Cr-Mo (ASTM F75) alloy. Co-Cr-Mo is known to be a difficult to cut material which, due to a combination of mechanical and physical properties, is...
1608.03091v1
2016-08-23
First-principles study on segregation of ternary additions for MoSi2/Mo5Si3 interface
We investigate segregation behavior of additive elements M (= Ni, Cr) at the C11b/D8m interface for MoSi2- Mo5Si3 alloys, based on first-principles calculation. We first find energetically stable interface structure with interface energy of 0.08 eV/A^2. Based on the stable interface, segregation energy for additive ele...
1608.06381v1
2016-09-08
Thermal and magnetic phase transition properties of a binary alloy spherical nanoparticle: A Monte Carlo simulation study
We have used the Monte Carlo (MC) simulation method with Metropolis algorithm to study the finite temperature phase transition properties of a binary alloy spherical nanoparticle with radius $r$ of the type $A_{p}B_{1-p}$. The system consists of two different species of magnetic components, namely, $A$ and $B$, and the...
1609.02317v1
2016-09-22
Recovering 0 Kelvin Effective Hamiltonian Parameters from High-Temperature Disordered Phases
Effective Hamiltonians, when used in tandem with statistical mechanics techniques, offer a rigorous connection between 0 Kelvin ab-initio predictions and finite temperature experimental observations. For alloys, cluster expansion Hamiltonians can coarse-grain out the complex, many-body electron problem of density funct...
1609.07175v1
2016-10-05
Prediction of irradiation induced microstructures in the AgCu model alloy using a multiscale method coupling atomistic and phase field modelling
In this work, a multiscale approach based on phase field was developed to simulate the microstructure's evolution under irradiation in binary systems, from atomic to microstructural scale. For that purpose, an efficient numerical scheme was developed. In the case of AgCu alloy under Krypton ions irradiation, phenomenol...
1610.01392v2
2016-10-06
Frequency estimate for multicomponent crystalline compounds
Among crystal structures of N-component metal alloys, far fewer examples are known with N>=4 than with N=2 or 3, in apparent contradiction to the exponentially growing number of possible combinations of elements. Two effects contribute to this shortfall. Since the N-component composition space resides within a d-dimens...
1610.02054v2
2016-10-22
Ab initio prediction of stable nanotwin double layers and 4O structure in Ni$_{2}$MnGa
The ab initio electronic structure calculations of the Ni$_{2}$MnGa The alloy indicate that the orthorhombic 4O structure exhibits the lowest energy compared to all known martensitic structures. The 4O structure is formed by nanotwin double layers, i.e., oppositely oriented nanotwins consisting of two (101) lattice pla...
1610.07083v3
2016-10-26
Non-diffusive Lattice Thermal Transport in Si-Ge Alloy Nanowires
We present a calculation of the lattice thermal conductivity of Si-Ge nanowires (NWs), based on solving the Boltzmann transport equation by the Monte Carlo method of sampling the phonon mean free paths. We augment the previous work with the full phonon dispersion and a partially diffuse momentum-dependent specularity m...
1610.08477v1
2016-10-27
A rational use of BCA code MARLOWE for ballistic effects of ion beam irradiation in the ion mixing formalism: comparison to Molecular Dynamics
Understanding ballistic effects caused by ion beam irradiation, and linking them with induced structure can be a key point for controlling and predicting the microstructure of irradiated materials. For this purpose, we have investigated ballistic effects from an ion mixing formalism point of view. The displacement casc...
1610.08659v1
2016-10-28
Spin-Orbit Torque Efficiency in Compensated Ferrimagnetic Cobalt-Terbium Alloys
Despite the potential advantages of information storage in antiferromagnetically coupled materials, it remains unclear whether one can control the magnetic moment orientation efficiently because of the cancelled magnetic moment. Here, we report spin-orbit torque induced magnetization switching of ferrimagnetic Co1-xTbx...
1610.09200v1
2016-11-15
Topologically ordered magnesium-biopolymer hybrid composite structures
Magnesium and its alloys are intriguing as possible biodegradable biomaterials due to their unique combination of biodegradability and high specific mechanical properties. However, uncontrolled biodegradation of magnesium during implantation remains a major challenge in spite of the use of alloying and protective coati...
1611.04923v1
2016-11-17
Sub 100-ps dynamics of the anomalous Hall effect at THz frequencies
We report about the anomalous Hall effect in 4f 3d metallic alloys measured using terahertz time-domain spectroscopy. The strength of the observed terahertz spin-dependent transport phenomenon is in good agreement with expectations based on electronic transport measurements. Employing this effect, we succeeded to revea...
1611.06251v1
2016-11-21
On the miscibility gap of Cu-Ni system
The existence of the miscibility gap in the Cu-Ni system has been an issue in both computational and experimental discussions for half a century [Chakrabarti et al., Phase diagrams of binary nickel alloys, ASM, 1991]. Here we propose a new miscibility gap in the Cu-Ni system measured in nano-layered thin films by Secon...
1611.07068v3
2016-11-22
Robust Bain distortion in the premartensite phase of platinum substituted Ni2MnGa magnetic shape memory alloy
The premartensite phase of shape memory and magnetic shape memory alloys (MSMAs) is believed to be a precursor state of the martensite phase with preserved austenite phase symmetry. The thermodynamic stability of the premartensite phase and its relation to the martensitic phase is still an unresolved issue, even though...
1611.07538v2
2017-01-03
First-principles modeling of the Invar effect in Fe65Ni35 by the spin-wave method
Thermal lattice expansion of the Invar Fe65Ni35 alloy is investigated in first-principles calculations using the spin-wave method, which is generalized here for the ferromagnetic state with short range order. It is shown that magnetic short-range order effects make substantial contribution to the equilibrium lattice co...
1701.00618v5
2017-01-13
Control of surface induced phase separation in immiscible semiconductor alloy core-shell nanowires
Semiconductor nanowires have been shown to exhibit novel optoelectronic properties with respect to bulk specimens made of the same material. However, if a semiconductor alloy has a miscibility gap in its phase diagram, at equilibrium it will phase separate, leading to deterioration of the aforementioned properties. One...
1701.03749v1
2017-01-24
Grain boundary diffusion in severely deformed Al-based alloy
Grain boundary diffusion in severely deformed Al-based AA5024 alloy is investigated. Different states are prepared by combination of equal channel angular processing and heat treatments, with the radioisotope $^{57}$Co being employed as a sensitive probe of a given grain boundary state. Its diffusion rates near room te...
1701.06694v1
2017-03-09
Transport properties of iron at the Earth's core conditions: the effect of spin disorder
The electronic and thermal transport properties of the Earth's core are crucial for many geophysical models such as the geodynamo model of the Earth's magnetic field and of its reversals. Here we show, by considering bcc-iron and iron-rich iron-silicon alloy as a representative of the Earth's core composition and apply...
1703.03205v3
2017-03-10
Elastic stability and lattice distortion of refractory high entropy alloys
Refractory high entropy alloys containing elements from the Ti, V and Cr columns of the periodic table form body centered cubic (BCC) structures. Elements from the Ti column are noteworthy because they take the BCC structure at high temperature but undergo a shear instability and transform to the hexagonal (HCP) struct...
1703.03727v1
2017-03-14
Electronic structure and magnetic properties in $T_2\text{AlB}_2$ ($T$ = Fe, Mn, Cr, Co, and Ni) and their alloys
The electronic structure and intrinsic magnetic properties of $\text{Fe}_2\text{AlB}_2$-related compounds and their alloys have been investigated using density functional theory. For $\text{Fe}_2\text{AlB}_2$, the crystallographic $a$ axis is the easiest axis, which agrees with experiments. The magnetic ground state of...
1703.04755v1
2017-03-15
Uniform diamond coatings on WC-Co hard alloy cutting inserts deposited by a microwave plasma CVD
Polycrystalline diamond coatings have been grown on cemented carbide substrates with different aspect ratios by a microwave plasma CVD in methane-hydrogen gas mixtures. To protect the edges of the substrates from non-uniform heating due to the plasma edge effect, a special plateholder with pockets for group growth has ...
1703.05211v1
2017-03-22
Local electronic properties of the graphene-protected giant Rashba-split BiAg$_2$ surface
We report the preparation of the interface between graphene and the strong Rashba-split BiAg$_2$ surface alloy and investigatigation of its structure as well as the electronic properties by means of scanning tunneling microscopy/spectroscopy and density functional theory calculations. Upon evaluation of the quasipartic...
1703.07721v1
2017-03-29
3$d$ - 4$d$ hybridization anomaly in Ni$_x$Pd$_{1-x}$ alloys at quantum critical point
$First-principles$ density functional theory computations of electronic structure and local magnetic properties of the non-fluctuating ground state of Ni$_x$Pd$_{1-x}$ alloy system around its quantum critical point $x_c = 0.026$ have been performed. The density of states at the Fermi energy and certain other parameters...
1703.09967v1
2017-07-04
One step growth of GaN/SiO2 core/shell nanowire in vapor-liquid-solid route by chemical vapor deposition technique
GaN/SiO2 core/shell nanowires are grown by cobalt phthalocyanine catalyst assisted vapor-liquid-solid route, in which Si wafer coated with a mixture of gallium and indium is used as the source for Ga and Si and ammonia is used as the precursor for nitrogen and hydrogen. Gallium in the presence of indium and hydrogen, w...
1707.00871v1
2017-07-14
Theoretical Design of Solid Electrolytes with Superb Ionic Conductivity: Alloying Effect on Li+ Transportation in Cubic Li6PA5X Chalcogenides
It is of great importance to develop inorganic solid electrolytes with high ionic conductivity, thus enabling solid state Li-ion batteries to address the notorious safety issue about the current technology due to use of highly flammable liquid organic electrolytes. On the basis of systematic first principles modelling,...
1707.04541v1
2017-07-20
Microstructure-based fatigue life model of metallic alloys with bilinear Coffin-Manson behavior
A microstructure-based model is presented to predict the fatigue life of polycrystalline metallic alloys which present a bilinear Coffin-Manson relationship. The model is based in the determination of the maximum value of a fatigue indicator parameter obtained from the plastic energy dissipated by cycle in the microstr...
1707.06605v2
2017-08-04
Tunable Spin-Orbit Torques in Cu-Ta Binary Alloy Heterostructures
The spin Hall effect (SHE) is found to be strong in heavy transition metals (HM), such as Ta and W, in their amorphous and/or high resistivity form. In this work, we show that by employing a Cu-Ta binary alloy as buffer layer in an amorphous Cu$_{100-x}$Ta$_{x}$-based magnetic heterostructure with perpendicular magneti...
1708.01356v1
2017-08-04
Effect of stacking fault energy on nucleation limited plasticity in Cu-Al alloys
We study the effect of Stacking Fault Energy (SFE) on the deformation behaviour of copper and copper-aluminium alloys using Molecular Dynamics (MD) simulation. We find that both yield stress and the magnitude of stress drop at yield decrease with increasing Al content. This "anomalous" softening behaviour is explained ...
1708.01378v1
2017-08-06
On the limits of coercivity in permanent magnets
The maximum coercivity that can be achieved for a given hard magnetic alloy is estimated by computing the energy barrier for the nucleation of a reversed domain in an idealized microstructure without any structural defects and without any soft magnetic secondary phases. For Sm$_{1-z}$Zr$_z$(Fe$_{1-y}$Co$_y$)$_{12-x}$Ti...
1708.01880v1
2017-08-21
Properties of $(TiZrNbCu)_{1-x}$$Ni_{x}$ Metallic Glasses
Recent studies (J. Alloys Compd. 695 (2017) 2661) of the electronic structure and properties of $(TiZrNbCu)_{1-x}$$Ni_{x}$ (x$\leq$0.25) amorphous high entropy alloys (a-HEA) have been extended to x=0.5 in order to compare behaviours of a-HEA and conventional Ni-base metallic glasses (MG). The amorphous state of all sa...
1708.06171v2
2017-08-22
Superconducting MoSi nanowires
We have fabricated disordered superconducting nanowires of molybdenium silicide. A molybdenium nanowire is first deposited on top of silicon, and the alloy is formed by rapid thermal annealing. The method allows tuning of the crystal growth to optimise, e.g., the resistivity of the alloy for potential applications in q...
1708.06629v2
2017-08-29
Electron-phonon coupling mechanisms for hydrogen-rich metals at high pressure
The mechanisms for strong electron-phonon coupling predicted for hydrogen-rich alloys with high superconducting critical temperature ($T_c$) are examined within the Migdal-Eliashberg theory. Analysis of the functional derivative of $T_c$ with respect to the electron-phonon spectral function shows that at low pressures,...
1708.08870v2
2017-08-31
Overcoming the time limitation in Molecular Dynamics simulation of crystal nucleation: a persistent-embryo approach
The crystal nucleation from liquid in most cases is too rare to be accessed within the limited timescales of the conventional molecular dynamics (MD) simulation. Here, we developed a "persistent embryo" method to facilitate crystal nucleation in MD simulations by preventing small crystal embryos from melting using exte...
1709.00085v2
2017-09-12
On atomic structure of Guinier-Preston Zone in Mg-Zn-Gd alloy
The atomic structure of Guinier-Preston (G.P.) zone in an Mg-Zn-Gd alloy has been determined by combining atomic resolution high angle annular dark field (HAADF) scanning transmission electron microscopy (STEM) and first-principles calculation. The G.P. Zone consists of three atomic layers paralleling to (0001) plane o...
1709.03769v1
2017-09-25
Ballistic transport of long wavelength phonons and thermal conductivity accumulation in nanograined silicon-germanium alloys
Computationally efficient modeling of the thermal conductivity of materials is crucial to thorough experimental planning and theoretical understanding of thermal properties. We present a modeling approach in this work that utilizes frequency-dependent effective medium to calculate lattice thermal conductivity of nanost...
1709.08688v1
2017-11-03
Thermal conductivity of rare-earth scandates in comparison to other oxidic substrate crystals
High-temperature thermal properties of three neighboring rare-earth scandates DyScO$_3$, TbScO$_3$ and GdScO$_3$ were compared to La$_{0.29}$Sr$_{0.71}$Al$_{0.65}$Ta$_{0.35}$O$_3$ (LSAT) and sapphire. To calculate thermal conductivity, heat capacity and thermal diffusivity were measured by differential scanning calorim...
1711.01078v1
2017-11-07
Dynamical, structural and chemical heterogeneities in a binary metallic glass-forming liquid
As approaching the glass transition, particle motion in liquids becomes highly heterogeneous and regions with virtually no mobility coexist with liquid-like domains. This complex dynamics is believed to be responsible for different phenomena including non-exponential relaxation and the breakdown of Stokes-Einstein rela...
1711.02298v1
2017-11-08
Magnetization measurements on as prepared and annealed Fe3-xMnxSi alloys
The magnetic properties of the alloy system Fe3-xMnxSi have been studied by measuring magnetization for samples with x = 0, 0.1, 0.25, 0.5, and by thermal scanning techniques for samples with x = 0, 0.1. The results reveal that the system is ferromagnetic in this composition range. Zero field cooling and field cooling ...
1711.03052v1
2017-11-15
Solubility in Zr-Nb alloys from first-principles
The thermodynamic properties of the Zr-Nb alloy are investigated at temperatures below 890 K with ab initio calculations. The solution energies of the bcc Nb-rich and hcp Zr-rich solid solutions obtained within the framework of density functional theory are in good agreement with experimental data, although insufficien...
1711.05478v1
2017-11-16
Homogenization in magnetic-shape-memory polymer composites
Magnetic-shape-memory materials (e.g. specific NiMnGa alloys) react with a large change of shape to the presence of an external magnetic field. As an alternative for the difficult to manifacture single crystal of these alloys we study composite materials in which small magnetic-shape-memory particles are embedded in a ...
1711.06098v1
2017-11-27
Nucleation of stoichiometric compounds from liquid: the role of the kinetic factor
While the role of the free energy barrier during nucleation is a text-book subject the importance of the kinetic factor is frequently underestimated. We obtained both quantities from molecular dynamics (MD) simulations for the pure Ni and B2 phases in the Ni50Al50 and Cu50Zr50 alloys. The free-energy barrier was found ...
1711.09806v1
2017-12-04
In-situ formation of SiGe alloy by electron beam evaporation and the effect of post deposition annealing on the energy band gap
We report the synthesis of polycrystalline (poly)-SiGe alloy thin films through solid state reaction of Si/Ge multilayer thin films on Si and glass substrates at low temperature of 500 {\deg}C. The pristine thin film was deposited using electron beam evaporation with optimized in-situ substrate heating. Our results sho...
1712.01036v1
2018-01-01
Efficient Switching of 3-Terminal Magnetic Tunnel Junctions by the Giant Spin Hall Effect of $\rm{Pt}_{85}\rm{Hf}_{15}$ Alloy
Recent research has indicated that introducing impurities that increase the resistivity of Pt can enhance the efficiency of the spin Hall torque it generates. Here we directly demonstrate the usefulness of this strategy by fabricating prototype 3-terminal in-plane-magnetized magnetic tunnel junctions that utilize the s...
1801.00411v1
2018-01-04
The surface-tension-driven Benard conventions and unique sub-grain cellular microstructures in 316L steel selective laser melting
The unique sub-grain patterns have been found in some particular alloys (316L, Al-Si, Co-Cr-Mo) selective laser melting (SLM), the submicron-scale cellular, elongated cellular or even band structures are always coexisting inside one single macro-solidified grain. Furthermore, the cellular structures are symmetrical wit...
1801.01408v1
2018-01-25
Convex Integration Arising in the Modelling of Shape-Memory Alloys: Some Remarks on Rigidity, Flexibility and Some Numerical Implementations
We study convex integration solutions in the context of the modelling of shape-memory alloys. The purpose of the article is two-fold, treating both rigidity and flexibility properties: Firstly, we relate the maximal regularity of convex integration solutions to the presence of lower bounds in variational models with su...
1801.08503v1
2018-03-07
Saturation and negative temperature coefficient of electrical resistivity in liquid iron-sulfur alloys at high densities from first principles calculations
We report results on electronic transport properties of liquid Fe-S alloys at conditions of planetary cores, computed by first-principle techniques in the Kubo-Greenwood formalism. We describe a combined effect of resistivity saturation due to temperature, compression, and chemistry by comparing the electron mean free ...
1803.02649v1
2018-03-27
Epitaxial growth of highly strained antimonene on Ag (111)
The synthesis of antimonene, which is a promising group-V 2D material for both fundamental studies and technological applications, remains highly challenging. Thus far, it has been synthesized only by exfoliation or growth on a few substrates. In this study, we show that thin layers of antimonene can be grown on Ag (11...
1803.09865v1
2018-03-27
Optical properties of BAlN and BGaN for applications in latticematched UV optical structures
The optical properties of BAlN and BGaN ternary alloys are investigated using first-principle calculation. Hybrid density functional theory is applied to determine the refractive indices of different alloys. A peculiar non-linear behavior of the static refractive index as a function of boron composition is found. The r...
1803.10011v3
2018-04-25
Influence of kinetic effects on terminal solid solubility of hydrogen in zirconium alloys
The integrity of irradiated zirconium based nuclear fuel cladding is related to the precipitation of hydrides which is closely connected with the solubility of hydrogen. A review on the development of measurement technologies is given and the resulting terminal solid solubilities are reflected with respect to the estab...
1805.00529v2
2018-05-03
Synchrotron X-ray tomography investigation of 3D morphology of intermetallic phases and pores and their effect on the mechanical properties of cast Al-Cu alloys
The influence of Fe content on the three-dimensional (3D) morphology of Fe-rich intermetallic phases (Fe phases), Al2Cu, and pores and mechanical properties of cast Al-5.0Cu-0.6Mn alloys with 0.5 and 1.0 wt. % Fe are characterized using synchrotron X-ray tomography and a tensile test. The results show that both Fe phas...
1805.01100v1
2018-05-14
Complete long-term corrosion protection with chemical vapor deposited graphene
Despite the numerous reports on the topic, examples of chemical vapor deposited (CVD) graphene-based anticorrosive coatings able to provide long-term protection (i.e., several months) of metals are still unavailable. Here, we finally present a polymer-graphene hybrid coating, comprising two single layers of CVD graphen...
1805.05102v1
2018-05-24
Interface characteristics in an α+β titanium alloy
The alpha/beta interface in Ti-6Al-2Sn-4Zr-6Mo (Ti-6246) is investigated via centre of symmetry analysis, both as-grown and after 10% cold work. Semi-coherent interface steps are observed at a spacing of 4.5 +/-1.13 atoms in the as-grown condition, in good agreement with theory prediction (4.37 atoms). Lattice accommod...
1805.09882v4
2018-05-25
Calculating the transport properties of magnetic materials from first-principles including thermal and alloy disorder, non-collinearity and spin-orbit coupling
A density functional theory based two-terminal scattering formalism that includes spin-orbit coupling and spin non-collinearity is described. An implementation using tight-binding muffin-tin orbitals combined with extensive use of sparse matrix techniques allows a wide variety of inhomogeneous structures to be flexibly...
1805.10062v1
2018-05-25
High throughput evaluation of the effect of Mg concentration on natural ageing of Al-Cu-Li-(Mg) alloys
The effect of Mg content on the natural ageing of Al-Cu-Li-(Mg) alloys has been investigated on a compositionally graded material made by linear friction welding, allowing to probe Mg contents between 0 and 0.4 at.%. High throughput time-and space-resolved characterization of natural ageing kinetics has been achieved u...
1805.10215v1
2018-06-27
Dynamic interface formation in magnetic thin film heterostructures
Magnetic thin film heterostructures have been widely studied for fundamental interests in the emergence of novel phenomena accompanied by the heterointerface formation as well as their promising practical potential. Combining x-ray magnetic circular dichroism with scanning tunneling microscopy, we show for Mn/Fe thin f...
1806.10543v1
2018-09-13
Important descriptors and descriptor groups of Curie temperatures of rare-earth transition-metal binary alloys
We analyze Curie temperatures of rare-earth transition metal binary alloys with machine learning method. In order to select important descriptors and descriptor groups, we introduce newly developed subgroup relevance analysis and adopt the hierarchical clustering in the representation. We execute the exhaustive search ...
1809.04750v2
2018-09-13
Quantitative phase field modeling of solute trapping and continuous growth kinetics in rapid solidification
Solute trapping is an important phenomenon in rapid solidification of alloys, for which the continuous growth model (CGM) is a popular sharp interface theory. Using matched asymptotic analysis, we show how to quantitatively map the sharp interface behavior of a binary alloy phase field model onto the CGM kinetics of Az...
1809.05148v1
2018-09-17
Tetragonal CuMnAs alloy: role of defects
The antiferromagnetic (AFM) CuMnAs alloy with tetragonal structure is a promising material for the AFM spintronics. The resistivity measurements indicate the presence of defects about whose types and concentrations is more speculated as known. We confirmed vacancies on Mn or Cu sublattices and Mn$_{\rm Cu}$ and Cu$_{\r...
1809.06239v1
2018-09-15
Interfacial polyconvex energy-enhanced evolutionary model for shape memory alloys
A sharp-interface model describing static equilibrium configurations of shape mory alloys by means of interfacial polyconvex energy density introduced by \v{S}ilhav\'y in 2010 and extended to a quasistatic situation by Kn\"upfer and Kru\v{z}\'ik in 2016 is computationally tested. Elastic properties of variants of marte...
1809.06698v2
2018-09-21
Critical Analysis of an FeP Empirical Potential Employed to Study Fracture of Metallic Glasses
An empirical potential that has been widely used to perform molecular dynamics studies on the fracture behavior of FeP metallic glasses is shown to exhibit spinodal decomposition in the composition range commonly studied. The phosphorous segregation induces a transition from ductility to brittleness. During brittle fra...
1809.08173v1
2018-09-24
An atomistic investigation of the interaction of dislocations with Guinier-Preston zones in Al-Cu alloys
The interaction between edge dislocations and Guinier-Preston zones in an Al-Cu alloy was analyzed by means of atomistic simulations. The different thermodynamic functions that determine the features of these obstacles for the dislocation glide were computed using molecular statics, molecular dynamics and the nudged el...
1809.09022v1
2018-09-24
Machine-learned multi-system surrogate models for materials prediction
Surrogate machine-learning models are transforming computational materials science by predicting properties of materials with the accuracy of ab initio methods at a fraction of the computational cost. We demonstrate surrogate models that simultaneously interpolate energies of different materials on a dataset of 10 bina...
1809.09203v2
2018-09-27
Influence of KCl and HCl on a Laser Clad FeCrAl Alloy: In-Situ SEM and Controlled Environment High Temperature Corrosion
Increasing pressure on the power industry to reduce carbon emissions has led to increased research into the use of biomass feedstocks. This work investigates the effects of HCl and KCl, key species influencing biomass boiler corrosion, on a laser clad coating of the FeCrAl alloy Kanthal APMT. In-Situ SEM exposure of th...
1809.10472v1
2018-09-27
$\mathrm{Fe}_{1-x}\mathrm{Ni}_x$ Alloy Nanoparticles Encapsulated inside Carbon Nanotubes: Controlled Synthesis, Structure and Magnetic Properties
In the present work, different synthesis procedures have been demonstrated to fill carbon nanotubes (CNTs) with $\mathrm{Fe}_{1-x}\mathrm{Ni}_x$ alloy nanoparticles (x = 0.33, 0.5). CNTs act as templates for the encapsulation of magnetic nanoparticles, and provide a protective shield against oxidation as well as preven...
1809.10500v1
2018-09-27
Kinetic Pathways of Phase Decomposition Using Steepest-Entropy-Ascent Quantum Thermodynamics Modeling. Part II: Phase Separation and Ordering
The kinetics of ordering and concurrent ordering and clustering is analyzed with an equation of motion initially developed to account for dissipative processes in quantum systems. A simplified energy eigenstructure, or pseudo-eigenstructure, is constructed from a static concentration wave method to describe the configu...
1809.10633v1
2018-11-13
X-ray magnetic linear dichroism as a probe for non-collinear magnetic state in ferrimagnetic single layer exchange bias systems
Ferrimagnetic alloys are extensively studied for their unique magnetic properties leading to possible applications in perpendicular magnetic recording, due to their deterministic ultrafast switching and heat assisted magnetic recording capabilities. On a prototype ferrimagnetic alloy we demonstrate fascinating properti...
1811.05362v1
2018-11-16
Ensemble versus Local Restructuring of Core-shell Nickel-Cobalt Nanoparticles upon Oxidation and Reduction Cycles
Bimetallic nanoparticles are widely studied, for example in catalysis. However, possible restructuring in the environment of use, such as segregation or alloying, may occur. Taken individually, state-of-the-art analytical tools fail to give an overall picture of these transformations. This study combines an ensemble an...
1811.06900v1
2018-11-19
Pulsed thermal deposition of binary and ternary transition metal dichalcogenide monolayers and heterostructures
Application of transition metal dichalcogenides (TMDC) in photonic, optoelectronic or valleytronic devices requires the growth of continuous monolayers, heterostructures and alloys of different materials in a single process. We present a facile pulsed thermal deposition method which provides precise control over layer ...
1811.07663v2
2018-11-26
Local order in binary Ge-Te glasses - an experimental study
The structure of $\mathrm{Ge}_x\mathrm{Te}_{100-x}$ (x = 14.5, 18.7, 23.6) glasses prepared by twin roller quenching technique was investigated by neutron diffraction, X-ray diffraction and Ge-K-edge X-ray absorption spectroscopy measurements. Large scale structural models were obtained for each composition by fitting ...
1811.10341v1
2019-11-05
Yield-stress anomaly in equiatomic ZrNbTiVHf high-entropy alloys
We have carried out plastic deformation experiments on single-phase samples of the body centered ZrNbTiVHf high-entropy alloy between room temperature and 1150 K. The experiments were carried out on polycrystalline samples with two different grain sizes, in compression at a true constant strain rate of 10-4 1/s. Increm...
1911.01887v1
2019-11-06
Thermally activated diffusion and lattice relaxation in (Si)GeSn materials
Germanium-Tin (GeSn) alloys have emerged as a promising material for future optoelectronics, energy harvesting and nanoelectronics owing to their direct bandgap and compatibility with existing Si-based electronics. Yet, their metastability poses significant challenges calling for in-depth investigations of their therma...
1911.02334v1
2019-11-19
Magneto-structural correlations in a systematically disordered B2 lattice
Ferromagnetism in certain B2 ordered alloys such as Fe$_{60}$Al$_{40}$ can be switched on, and tuned, via antisite disordering of the atomic arrangement. The disordering is accompanied by a $\sim$1 % increase in the lattice parameter. Here we performed a systematic disordering of B2 Fe$_{60}$Al$_{40}$ thin films, and o...
1911.08404v1
2019-11-22
Proximity effect in [Nb(1.5nm)/Fe(x)]$_{10}$/Nb(50nm) superconducting/ferromagnet heterostructures
We have investigated the structural, magnetic and superconducting properties of [Nb(1.5nm)/Fe(x)]$_{10}$ superlattices deposited on a thick Nb(50nm) layer. Our investigation showed that the Nb(50nm) layer grows epitaxially at 800$^\circ$C on Al$_2$O$_3$(1$\bar{1}$02) substrate. Samples grown at this condition posses a ...
1911.10168v2
2019-11-24
Rapid one-step synthesis and compaction of high-performance n-type Mg3Sb2 thermoelectrics
n-type Mg3Sb2-based compounds are emerging as a promising class of low-cost thermoelectric materials due to their extraordinary performance at low and intermediate temperatures. However, so far high thermoelectric performance has merely been reported in n-type Mg3Sb2-Mg3Bi2 alloys with a large amount of Bi. Moreover, c...
1911.10549v1
2020-01-08
Magnetic correlations in the disordered ferromagnetic alloy Ni-V revealed with small angle neutron scattering
We present small angle neutron scattering (SANS) data collected on polycrystalline Ni$_{1-x}$V$_x$ samples with $x\geq0.10$ with confirmed random atomic distribution. We aim to determine the relevant length scales of magnetic correlations in ferromagnetic samples with low critical temperatures $T_c$ that show signs of ...
2001.02706v1
2020-01-13
Finite strain constitutive modeling for shape memory alloys considering transformation-induced plasticity and two-way shape memory effect
This work presents a three-dimensional constitutive model for shape memory alloys considering the TRansformation-Induced Plasticity (TRIP) as well as the Two-Way Shape Memory Effect (TWSME) through a large deformation framework. The presented logarithmic strain based model is able to capture the large strains and rotat...
2001.04551v1
2020-01-14
Superconducting properties of high-entropy-alloy tellurides M-Te (M: Ag, In, Cd, Sn, Sb, Pb, Bi) with a NaCl-type structure
High-entropy-alloy-type tellurides M-Te, which contain five different metals of M = Ag, In, Cd, Sn, Sb, Pb, and Bi, were synthesized using high pressure synthesis. Structural characterization revealed that all the obtained samples have a cubic NaCl-type structure. Six samples, namely AgCdSnSbPbTe5, AgInSnSbPbTe5, AgCdI...
2001.04640v1
2020-01-15
Anisotropic behavior of TiB2 nanoparticles reinforced 2024Al composites rolling sheet
The in-plane anisotropy (IPA) of mechanical properties existed in plate products is often undesired since it limits the industrial application and increases the difficulty of material processing. It is thus one of the important factors which requires strict control during the manufacture of high-performance aluminum al...
2001.05144v1
2020-01-17
Dissociated dislocation-mediated carbon transport and diffusion in austenitic iron
Dislocation-solute interaction plays fundamental roles in mechanical properties of alloys. Here, we disclose the essential features of dislocation-carbon interaction in austenitic Fe at the atomistic scale. We show that passage of a Shockley partial dislocation in face-centered cubic iron is able to move carbon atoms o...
2001.06196v1
2020-01-18
Microscopic aspects of artificial ageing in Al-Mg-Si alloys
Al-Mg-Si alloys with total solute contents ranging from 0.8 to 1.4 wt.% were solutionised, quenched and then artificially aged (AA) at 180 {\deg}C, after which positron annihilation lifetime spectroscopy was applied to obtain information about precipitation and vacancy evolution during preceding ageing. Hardness and el...
2001.06566v1
2020-01-23
Synthesis of RE123 high-Tc superconductors with a high-entropy-alloy-type RE site
We have synthesized high-entropy-alloy-type (HEA-type) RE123 superconductors Y0.28Nd0.16Sm0.18Eu0.18Gd0.20Ba2Cu3O7-d and Y0.18La0.24Nd0.14Sm0.14Eu0.15Gd0.15Ba2Cu3O7-d with a superconducting transition temperature (Tc) exceeding 90 K. From comparison between HEA-type and conventional RE123 samples, we found that the mix...
2001.08365v1
2021-07-01
Evidence for Higher order topology in Bi and Bi$_{0.92}$Sb$_{0.08}$
Higher order topological insulators (HOTIs) are a new class of topological materials which host protected states at the corners or hinges of a crystal. HOTIs provide an intriguing alternative platform for helical and chiral edge states and Majorana modes, but there are very few known materials in this class. Recent stu...
2107.00698v4
2021-07-13
Glassy nature of Ce65Al25Co10 alloy: A metallic glass
In the present investigation the glass forming ability of Ce65Al25Co10 metallic glass has been reported. It was successfully synthesised using melt spinning techniques. The existence of amorphous phase in Ce65Al25Co10 alloy have been proved using X-ray diffraction (XRD) and transmission electron microscopy (TEM) measur...
2107.05809v2
2021-07-29
Synergetic enhancement of power factor and suppression of lattice thermal conductivity via electronic structure modification and nanostructuring on Ni and B co-doped p-type Si-Ge alloy
For simultaneously achieving the high-power factor and low lattice thermal conductivity of Si-Ge based thermoelectric materials, we employed, in this study, constructively modifying the electronic structure near the chemical potential and nano-structuring by low temperature and high-pressure sintering on nano-crystalli...
2107.13778v1
2017-04-22
Evolution of texture and microstructure during accumulative roll bonding of aluminum AA5086 alloy
In the present investigation, a strongly bonded strip of an aluminium-magnesium based alloy AA5086 is successfully produced through accumulative roll bonding (ARB). A maximum of up to eight passes has been used for the purpose. Microstructural characterization using electron backscatter diffraction (EBSD) technique ind...
1704.06732v1
2017-04-27
High efficiency deep-UV emission at 219 nm from ultrathin MBE GaN/AlN quantum heterostructures
Deep ultraviolet (UV) optical emission below 250 nm (~5 eV) in semiconductors is traditionally obtained from high aluminum containing AlGaN alloy quantum wells. It is shown here that high-quality epitaxial ultrathin binary GaN quantum disks embedded in an AlN matrix can produce efficient optical emission in the 219-235...
1704.08737v1
2017-05-03
First principles study of bimetallic Ni$_{13-n}$Ag$_n$ nano-clusters ($n =$ 0$-$13) : Structural, mixing, electronic and magnetic properties
Using spin polarized density functional theory (DFT) based calculations, combined with ab-initio molecular dynamics simulation, we carry out a systematic investigation of the bimetallic Ni$_{13-n}$Ag$_n$ nano clusters, for all compositions. This includes prediction of the geometry, mixing behavior, and electronic prope...
1705.01470v1
2017-05-09
Native surface oxide turns alloyed silicon membranes into nanophononic metamaterials with ultra-low thermal conductivity
A detailed understanding of the relation between microscopic structure and phonon propagation at the nan oscale is essential to design materials with desired phononic and thermal properties.Here we uncover a new mechanism of phonon interaction in surface oxidized membranes, i.e., native oxide layers interact with phono...
1705.03143v1
2017-05-11
Oxygen - Dislocation interaction in zirconium from first principles
Plasticity in zirconium alloys is mainly controlled by the interaction of 1/3 1210 screw dislocations with oxygen atoms in interstitial octahedral sites of the hexagonal close-packed lattice. This process is studied here using ab initio calculations based on the density functional theory. The atomic simulations show th...
1705.04075v1
2017-05-18
On the primary spacing and microsegregation of cellular dendrites in laser deposited Ni-Nb alloys
In this study, an alloy phase-field model is used to simulate solidification microstructures at different locations within a solidified molten pool. The temperature gradient $G$ and the solidification velocity $V$ are obtained from a macroscopic heat transfer finite element simulation and provided as input to the phase...
1705.06669v2
2018-07-25
Role of interfaces in the biased composition of TbFe(Co) thin films
Ferrimagnetic TbFe or TbFeCo amorphous alloy thin films have been grown by co-evaporation in ultra-high vacuum. They exhibit an out-of-plane magnetic anisotropy up to their Curie temperature with a nucleation and propagation reversal mechanism suitable for current induced domain wall motion. Rutherford back scattering ...
1807.09570v1
2018-07-25
Correlated electronic structure with uncorrelated disorder
We introduce a computational scheme for calculating the electronic structure of random alloys that includes electronic correlations within the framework of the combined density functional and dynamical mean-field theory. By making use of the particularly simple parameterization of the electron Green's function within t...
1807.09582v2
2018-07-25
Dislocation-Solute Cluster Interaction in Al-Mg Binary Alloys
The close-range interaction of dislocations and solute clusters in the Al-Mg binary system is studied by means of atomistic simulations. We evaluate the binding energy of dislocations to the thermodynamically stable solute atmospheres that form around their cores, at various temperatures and average solid solution conc...
1807.09888v1
2018-07-27
Current developments of nanoscale insight into corrosion protection by passive oxide films
Oxide passive films are a key for the durability of metals and alloys components as well as a central issue in corrosion science and engineering. Herein, we discuss current developments of the nanometer and sub-nanometer scale knowledge of the barrier properties and adsorption properties of passive oxide films brought ...
1807.10689v2
2018-10-08
Creation of oxide coating on Al 1050 alloy
Plasma electrolytic oxidation (PEO) is a surface processing for oxide coatings formation with advanced properties. Mostly, PEO is performed in an aqueous solution electrolyte which limits the dimension of treated parts due to the system heating up. Therefore, treatment of large surfaces cannot be applied in aqueous ele...
1810.03300v1
2018-10-02
Machine learning clustering technique applied to powder X-ray diffraction patterns to distinguish alloy substitutions
We applied the clustering technique using DTW (dynamic time wrapping) analysis to XRD (X-ray diffraction) spectrum patterns in order to identify the microscopic structures of substituents introduced in the main phase of magnetic alloys. The clustering is found to perform well to identify the concentrations of the subst...
1810.03972v2
2018-10-12
Controlling solid-liquid interfacial energy anisotropy through the isotropic liquid
Although the anisotropy of the solid-liquid interfacial free energy for most alloy systems is very small, it plays a crucial role in the growth rate, morphology and crystallographic growth direction of dendrites. Previous work posited a dendrite orientation transition via compositional additions. In this work we examin...
1810.05298v2
2018-10-12
Concentration-dependent atomic mobilities in FCC CoCrFeMnNi high-entropy alloys
The diffusion kinetics in a CoCrFeMnNi high entropy alloy is investigated by a combined radiotracer--interdiffusion experiment applied to a pseudo-binary Co$_{15}$Cr$_{20}$Fe$_{20}$Mn$_{20}$Ni$_{25}$ / Co$_{25}$Cr$_{20}$Fe$_{20}$Mn$_{20}$Ni$_{15}$ couple. As a result, the composition-dependent tracer diffusion coeffici...
1810.05430v1
2018-10-15
UV plasmonic properties of colloidal liquid-metal eutectic gallium-indium alloy nanoparticles
Nanoparticles made of non-noble metals such as gallium have recently attracted significant attention due to promising applications in UV plasmonics. To date, experiments have mostly focused on solid and liquid pure gallium particles immobilized on solid substrates. However, for many applications, colloidal liquid-metal...
1810.06163v1