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2011-11-03
Scaling Conception of Energy Loss' Separation in Soft Magnetic Materials
Data collapse enables comparison of measurement data measured in different laboratories on different samples. In the case of energy losses in Soft Magnetic Materials (SMM) the data collapse is possible to achieved only if the measurement data can be described by the two components formula. For more complicated cases we...
1111.0939v1
2012-02-14
Structural, elastic and thermal properties of cementite (Fe$_3$C) calculated using Modified Embedded Atom Method
Structural, elastic and thermal properties of cementite (Fe$_3$C) were studied using a Modified Embedded Atom Method (MEAM) potential for iron-carbon (Fe-C) alloys. Previously developed Fe and C single element potentials were used to develop an Fe-C alloy MEAM potential, using a statistically-based optimization scheme ...
1202.3068v7
2012-03-03
First-principles equation of state and phase stability for the Ni-Al system under high pressures
The equation of state (EOS) of alloys at high pressures is generalized with the cluster expansion method. It is shown that this provides a more accurate description. The low temperature EOSs of Ni-Al alloys on FCC and BCC lattices are obtained with density functional calculations, and the results are in good agreement ...
1203.0622v1
2012-05-23
Effect of He-ion irradiation on Fe-Cr alloys: Mössbauer - effect study
Effect of He ion irradiation on three model Fe(100-x)Cr(x) alloys (x =5.8, 10.75 and 15.15) was investigated with the conversion electron M\"ossbauer spectroscopy. The study of the alloys irradiated with 25 keV ions revealed that the strongest effect occured in the Fe(84.85)Cr(15.15) sample where an inversion of a shor...
1205.5187v1
2012-06-10
Magnetic glass in Shape Memory Alloy : Ni45Co5Mn38Sn12
The first order martensitic transition in the ferromagnetic shape memory alloy Ni45Co5Mn38Sn12 is also a magnetic transition and has a large field induced effect. While cooling in the presence of field this first order magnetic martensite transition is kinetically arrested. Depending on the cooling field, a fraction of...
1206.2024v2
2012-08-14
Numerical Simulations of the Invar Effect in Fe-Ni, Fe-Pt, and Fe-Pd Ferromagnets
The Invar effect in ferromagnetic Fe-Ni, Fe-Pt, and Fe-Pd alloys is investigated theoretically by means of a computationally efficient scheme. The procedure can be divided into two stages: study of magnetism and calculations of structural properties. In the first stage, an Ising model is considered and fractions of Fe ...
1208.2850v1
2012-10-24
Thermally induced structural modification in the Al/Zr multilayers
The effect of increasing temperature on the structural stability and interactions of two kinds of Al/Zr (Al(1%wtSi)/Zr and Al(Pure)/Zr) multilayer mirrors are investigated. All Al/Zr multilayers annealed from 200^{\circ}C to 500^{\circ}C, were deposited on Si wafers by using direct-current magnetron sputtering technolo...
1210.6442v1
2013-02-10
Skyrmions with varying size and helicity in composition-spread helimagnetic alloys
The chirality, i.e. left or right handedness, is an important notion in a broad range of science. In condensed matter, this occurs not only in molecular or crystal forms but also in magnetic structures. A magnetic skyrmion, a topologically-stable spin vortex structure, as observed in chiral-lattice helimagnets is one s...
1302.2319v1
2013-03-26
Hidden order in serrated flow of metallic glasses
We report results of statistical and dynamic analysis of the serrated stress-time curves obtained from compressive constant strain-rate tests on two metallic glass samples with different ductility levels in an effort to extract hidden information in the seemingly irregular serrations. Two distinct types of dynamics are...
1303.6483v1
2013-07-29
Electronic origin of the anomalous segregation behavior of Cr in Fe-rich Fe-Cr alloys
The energy of segregation of Cr from the bulk to the topmost surface layer in dilute Fe-Cr alloys is endothermic but small. On the other hand, the segregation energy from the bulk to the subsurface layer is not only endothermic but relatively large. Thus, the subsurface layer presents a huge barrier, not only for the s...
1307.7606v1
2013-10-15
Ab initio study of point defects in NiTi-based alloys
Changes in temperature or stress state may induce reversible B2$\leftrightarrow$(R)$\leftrightarrow$ B19' martensitic transformations and associated shape memory effects in close-to-stoichiometric nickel-titanium (NiTi) alloys. Recent experimental studies confirmed a considerable impact of the hydrogen-rich aging atmos...
1310.4189v2
2013-10-29
Derivation of 12- and 14-band $\textbf{k}\cdot\textbf{p}$ Hamiltonians for dilute bismide and bismide-nitride semiconductors
Using an $sp^{3}s^{*}$ tight-binding model we demonstrate how the observed strong bowing of the band gap and spin-orbit-splitting with increasing Bi composition in the dilute bismide alloy GaBi$_{x}$As$_{1-x}$ can be described in terms of a band-anticrossing interaction between the extended states of the GaAs valence b...
1310.7969v1
2013-11-24
An Environment-dependent Semi-Empirical Tight Binding Model Suitable for Electron Transport in Bulk Metals, Metal Alloys, Metallic Interfaces and Metallic Nanostructures I - Model and Validation
Semi-Empirical Tight Binding (TB) is known to be a scalable and accurate atomistic representation for electron transport for realistically extended nano-scaled semiconductor devices that might contain millions of atoms. In this paper an environment-aware and transferable TB model suitable for electronic structure and t...
1311.6082v1
2014-02-17
Near-substrate composition depth profile of direct current-plated and pulse-plated Fe-Ni alloys
Composition depth profiles of d.c.-plated and pulseplated Fe-Ni alloys have been investigated with the reverse depth profile analysis method. When d.c. plating is applied, the mole fraction of iron near the substrate is higher than during steadystate deposition since iron is preferentially deposited beside nickel and t...
1402.3943v1
2014-03-17
Second-order Perturbation Formula for Magnetocrystalline Anisotropy using Orbital Angular Momentum Matrix
We derive a second-order perturbation formula for an electronic system subject to spin-orbit interactions (SOI). The energy correction originates in the spin-conserving and the spin-flip transitions. The former are represented by the orbital angular momentum (OAM) acquired via the SOI. The latter come from the quantum ...
1403.3987v1
2014-05-05
Change of Cr atoms distribution in Fe85Cr15 alloy caused by 250 keV He+ ion irradiation to different doses
Redistribution of Cr atoms in a Fe85Cr15 alloy caused by its irradiation with 250 keV He ions to different doses viz. 5, 10 and 30 dpa was investigated by means of conversion electrons Mossbauer spectroscopy. The redistribution was expressed in terms of the Warren-Cowley short-range order parameters alpha1, alpha2 and ...
1405.0870v3
2014-05-13
Energetics, structure, and composition of nanoclusters in Oxide Dispersion Strengthened Fe-Cr alloys
Extensive first-principle calculations on embedded clusters containing few O, Y, Ti, and Cr atoms as well as vacancies are performed to obtain interaction parameters to be applied in Metropolis Monte Carlo simulations, within the framework of a rigid lattice model. A novel description using both pair and triple paramet...
1405.3041v1
2014-07-18
Crystal structure, thermodynamics, magnetics and disorder properties of Be-Fe-Al intermetallics
The elastic and magnetic properties, thermodynamical stability, deviation from stoichiometry and order/disorder transformations of phases that are relevant to Be alloys were investigated using density functional theory simulations coupled with phonon density of states calculations to capture temperature effects. A nove...
1407.5013v3
2014-09-25
Spin glass like ground state and observation of exchange bias in Mn_{0.8}Fe_{0.2}NiGe alloy
The ground-state magnetic properties of hexagonal equiatomic alloy of nominal composition Mn_{0.8}Fe_{0.2}NiGe were investigated through dc magnetization and heat capacity measurements. The alloy undergoes first order martensitic transition below 140 K with simultaneous development of long range ferromagnetic ordering ...
1409.7221v1
2014-10-19
Enabling microstructural changes of FCC/BCC alloys in 2D dislocation dynamics
Dimension reduction procedure is the recipe to represent defects in two dimensional dislocation dynamics according to the changes in the geometrical properties of the defects triggered by different conditions such as radiation, high temperature, or pressure. In the present study, this procedure is extended to incorpora...
1410.5094v2
2014-11-12
Quantum criticality and superconducting pairing in Ce(1-x)Yb(x)CoIn5 alloys
In this paper we review some of our recent experimental and theoretical results on transport and thermodynamic properties of heavy-fermion alloys Ce(1-x)Yb(x)CoIn5. Charge transport measurements under magnetic field and pressure on these single crystalline alloys revealed that: (i) relatively small Yb substitution supp...
1411.3368v1
2015-01-16
Phonon transmission across Mg2Si/Mg2Si1-xSnx interfaces: A first-principles-based atomistic Green's function study
Phonon transmission across interfaces of dissimilar materials has been studied intensively in the recent years by using atomistic simulation tools owing to its importance in determining the effective thermal conductivity of nanostructured materials. Atomistic Green's function (AGF) method with interatomic force constan...
1501.04084v1
2015-01-23
Tensile strain-induced softening of iron at high temperature
In weakly ferromagnetic materials, already small changes in the atomic configuration triggered by temperature or chemistry can alter the magnetic interactions responsible for the non-random atomic-spin orientation. Different magnetic states, in turn, can give rise to substantially different macroscopic properties. A cl...
1501.05774v2
2015-10-18
Magnetization dynamics in Fe$_x$Co$_{1-x}$ in presence of chemical disorder
In this paper, we present a theoretical formulation of magnetization dynamics in disordered binary alloys based on Kubo linear response theory interfaced with the combination of seamlessly three approaches; density functional based tight-binding linear muffin-tin orbitals, generalized recursion and Augmented space form...
1510.05200v4
2015-10-27
Interatomic repulsion softness directly controls the fragility of supercooled metallic melts
We present an analytic scheme to connect the fragility and viscoelasticity of metallic glasses to the effective ion-ion interaction in the metal. This is achieved by an approximation of the short-range repulsive part of the interaction, combined with nonaffine lattice dynamics to obtain analytical expressions for the s...
1510.08117v1
2015-12-04
Infrared dielectric function, phonon modes and free-charge carrier properties of high-Al-content Al$_x$Ga$_{1-x}$N alloys determined by mid-infrared spectroscopic ellipsometry and optical Hall effect
The phonon mode parameters and anisotropic mid-infrared dielectric function tensor components of high- Al-content Al$_x$Ga$_{1-x}$N alloys in dependence of the Al content $x$ are precisely determined from mid-infrared spectroscopic ellipsometry measurements for a set of high-quality Si-doped Al$_x$Ga$_{1-x}$N epitaxial...
1512.01427v1
2015-12-10
Electron-phonon coupling and thermal transport in the thermoelectric compound $\mathrm{Mo_3Sb_{7-x}Te_x}$
Phonon properties of $\mathrm{Mo_3Sb_{7-x}Te_x}$ ($x=0,1.5, 1.7$), a potential high-temperature thermoelectric material, have been studied with inelastic neutron and x-ray scattering, and with first-principles simulations. The substitution of Te for Sb leads to pronounced changes in the electronic structure, local bond...
1512.03120v1
2016-04-25
Quantitative description of short-range order and its influence on the electronic structure in Ag-Pd alloys
We investigate the effect of short-range order (SRO) on the electronic structure in alloys from the theoretical point of view using density of states (DOS) data. In particular, the interaction between the atoms at different lattice sites is affected by chemical disorder, which in turn is reflected in the fine structure...
1604.07238v1
2016-04-02
Modeling Mechanical Properties of Aluminum Composite Produced Using Stir Casting Method
ANN (Artificial Neural Networks) modeling methodology was adopted for predicting mechanical properties of aluminum cast composite materials. For this purpose aluminum alloy were developed using conventional foundry method. The composite materials have complex nature which posses the nonlinear relationship among heat tr...
1605.09691v1
2016-08-22
Superconducting Order from Disorder in 2H-TaSe$_{2-x}$S$_{x}$ (0$\leq$x$\leq$2)
We report on the emergence of robust superconducting order in single crystal alloys of 2H-TaSe$_{2-x}$S$_{x}$ (0$\leq$x$\leq$2) . The critical temperature of the alloy is surprisingly higher than that of the two end compounds TaSe$_{2}$ and TaS$_{2}$. The evolution of superconducting critical temperature T$_{c} (x)$ co...
1608.06275v2
2016-10-06
Automated Phase Mapping with AgileFD and its Application to Light Absorber Discovery in the V-Mn-Nb Oxide System
Rapid construction of phase diagrams is a central tenet of combinatorial materials science with accelerated materials discovery efforts often hampered by challenges in interpreting combinatorial x-ray diffraction datasets, which we address by developing AgileFD, an artificial intelligence algorithm that enables rapid p...
1610.02005v1
2016-10-10
Structural origins of the boson peak in metals: From high-entropy alloys to metallic glasses
The boson peak appears in all amorphous solids and is an excess of vibrational states at low frequencies compared to the phonon spectrum of the corresponding crystal. Until recently, the consensus was that it originated from "defects" in the glass. The nature of these defects is still under discussion, but the picture ...
1610.02911v2
2017-01-02
Thermoelectric power factor enhancement by spin-polarized currents - a nanowire case study
Thermoelectric (TE) measurements have been performed on the workhorses of today's data storage devices, exhibiting either the giant or the anisotropic magnetoresistance effect (GMR and AMR). The temperature-dependent (50-300 K) and magnetic field-dependent (up to 1 T) TE power factor (PF) has been determined for severa...
1701.00404v1
2017-03-18
The Effect of Na on Cu-K-In-Se Thin Film Growth
Co-evaporation of Cu-KF-In-Se was performed on substrates with varied surface Na compositions. Compositions of interest for photovoltaic absorbers were studied, with ratios of (K+Cu)/In ~ 0.85 and K/(K+Cu) ~ 0 - 0.57. Soda-lime glass (SLG) substrates led to the most Na by secondary ion mass spectrometry, while SLG/Mo a...
1703.06365v1
2017-09-06
Predicting the morphologies of γ' precipitates in cobalt-based superalloys
Cobalt-based alloys with {\gamma}/{\gamma}' microstructures have the potential to become the next generation of superalloys, but alloy compositions and processing steps must be optimized to improve coarsening, creep, and rafting behavior. While these behaviors are different than in nickel-based superalloys, alloy devel...
1709.02010v1
2017-11-29
Thermal contribution to the spin-orbit torque in metallic/ferrimagnetic systems
We report a systematic study of current-induced perpendicular magnetization switching in W/Co$_{x}$Tb$_{1-x}$/Al thin films with strong perpendicular magnetic anisotropy. Various Co$_{x}$Tb$_{1-x}$ ferrimagnetic alloys with different magnetic compensation temperatures are presented. The systems are characterized using ...
1711.10790v1
2018-01-10
Length-scale dependent average structures, piezoelectricity enhancement and depolarization mechanisms in a non-MPB high-performance piezoelectric alloy system PbTiO3-Bi(Zr1/2Ni1/2)O3
There is a general perception that large piezoelectric response in ferroelectric alloys requires tuning the system towards a morphotropic phase boundary (MPB), i.e., a composition driven inter-ferroelectric instability. Here we show that high piezoelectric response can be realized even in non-MPB alloy systems. This is...
1801.03310v1
2018-05-14
Theory and design of In$_{x}$Ga$_{1-x}$As$_{1-y}$Bi$_{y}$ mid-infrared semiconductor lasers: type-I quantum wells for emission beyond 3 $μ$m on InP substrates
We present a theoretical analysis and optimisation of the properties and performance of mid-infrared semiconductor lasers based on the dilute bismide alloy In$_{x}$Ga$_{1-x}$As$_{1-y}$Bi$_{y}$, grown on conventional (001) InP substrates. The ability to independently vary the epitaxial strain and emission wavelength in ...
1805.05223v1
2018-05-19
Electrochemical solid-state amorphization in the immiscible Cu-Li system: Size matters
As a typical immiscible binary system, copper (Cu) and lithium (Li) show no alloying and chemical intermixing under normal circumstances. A notable example that takes advantages of the immiscibility between Cu and Li is the widespread utilization of Cu foils as the anodic current collector in Li-ion batteries. Here we ...
1805.07551v1
2018-05-19
Discrete dislocation dynamics simulations of dislocation-$θ'$ precipitate interaction in Al-Cu alloys
The mechanisms of dislocation/precipitate interaction were studied by means of discrete dislocation dynamics within a multiscale approach. Simulations were carried out using the discrete continuous method in combination with a fast Fourier transform solver to compute the mechanical fields. The original simulation strat...
1805.07597v2
2018-06-12
Quantum-Accurate Spectral Neighbor Analysis Potential Models for Ni-Mo Binary Alloys and FCC Metals
In recent years, efficient inter-atomic potentials approaching the accuracy of density functional theory (DFT) calculations have been developed using rigorous atomic descriptors satisfying strict invariances, for example, to translation, rotation, permutation of homonuclear atoms, among others. In this work, we general...
1806.04777v2
2018-06-09
Effect of nano Co reinforcements on the structure of the Sn-3.0Ag-0.5Cu solder in liquid and after reflow solid states
Sn-Ag-Cu (SAC) alloys are commonly recognized as lead-free solders employed in the electronics industry. However, some disadvantages in mechanical properties and their higher melting temperatures compared to Pb-Sn solders prompt new research relating to reinforcement of existing SAC solders. One of the ways to reinforc...
1806.06935v1
2018-11-13
Dimension Engineering of Narrow Bandgap Semiconductor InAs Nanostructures in Wafer-Scale
Here, we demonstrate an approach that provides a precise control of the dimension of InAs from one-dimensional nanowires to wafer-scale free-standing two-dimensional nanosheets, which have a high degree of crystallinity and outstanding electrical and optical properties, using molecular-beam epitaxy by controlling catal...
1811.05111v1
2019-11-25
Natural-mixing guided design of refractory high-entropy alloys with as-cast tensile ductility
Multi-principal-element metallic alloys have created a growing interest that is unprecedented in metallurgical history, in exploring the property limits of metals and the governing physical mechanisms. Refractory high-entropy alloys (RHEAs) have drawn particular attention due to their (i) high melting points and excell...
1911.10975v1
2019-11-26
Proton Irradiation-Decelerated Intergranular Corrosion of Ni-Cr Alloys in Molten Salt
The effects of ionizing radiation on materials often reduce to "bad news." Radiation damage usually leads to detrimental effects such as embrittlement, accelerated creep, phase instability, and radiation-altered corrosion. This last point merits special attention. Elucidating synergies between radiation and corrosion h...
1911.11798v1
2020-01-14
Ultra-low threshold cw and pulsed lasing in tensile strained GeSn alloys
GeSn alloys are the most promising semiconductors for light emitters entirely based on group IV elements. Alloys containing more than 8 at.% Sn have fundamental direct band-gaps, similar to conventional III-V semiconductors and thus can be employed for light emitting devices. Here, we report on GeSn microdisk lasers en...
2001.04927v1
2020-01-18
Phase Transformation Characteristics of High-Temperature Shape Memory Alloy under Tension, Compression, and Bending Actuation Cycling
Shape Memory Alloys (SMAs) are a unique class of intermetallic alloys that can cyclically sustain large deformations and recover a designed geometry through a solid-to-solid phase transformation. SMAs provide favorable actuation energy density properties, making them suitable for engineering applications requiring a si...
2001.06739v1
2020-01-25
Polar InGaN/GaN quantum wells: Revisiting the impact of carrier localization on the green gap problem
We present a detailed theoretical analysis of the electronic and optical properties of c-plane InGaN/GaN quantum well structures with In contents ranging from 5% to 25%. Special attention is paid to the relevance of alloy induced carrier localization effects to the green gap problem. Studying the localization length an...
2001.09345v1
2017-03-28
Thermo-mechanical finite element analysis of the AA5086 alloy under warm forming conditions
Warm forming processes have been successfully applied at laboratory level to overcome some important drawbacks of the Al-Mg alloys, such as poor formability and large springback. However, the numerical simulation of these processes requires the adoption of coupled thermo-mechanical finite element analysis, using temper...
1704.00056v1
2017-03-18
Surface and Bulk Effects of K in Cu$_{1-x}$K$_x$In$_{1-y}$Ga$_y$Se$_2$ Solar Cells
Two strategies for enhancing photovoltaic (PV) performance in chalcopyrite solar cells were investigated: Cu1-xKxIn1-yGaySe2 absorbers with low K content (K/(K+Cu), or x ~ 0.07) distributed throughout the bulk, and CuIn1-yGaySe2 absorbers with KIn1-yGaySe2 grown on their surfaces. For the Ga-free case, increased temper...
1704.01593v1
2017-04-13
Low temperature physical properties of Co-35Ni-20Mo-10Cr alloy MP35N
Multiphase Co-35Ni-20Mo-10Cr alloy MP35N is a high strength alloy with excellent corrosion resistance. Its applications span chemical, medical, and food processing industries. Thanks to its high modulus and high strength, it found applications in reinforcement of ultra-high field pulsed magnets. Recently, it has also b...
1704.04275v1
2017-04-29
Wear-resistant thin films of MRI-230D-Mg alloy using plasma-driven electrolytic oxidation
Wear resistant coatings were produced on a permanent mould cast MRI 230D Mg alloy by (a) PEO in silicate based electrolyte, (b) PEO in phosphate based electrolyte, (c) hybrid coatings of silicate PEO followed by laser surface alloying (LSA) with Al and Al2O3, and (d) hybrid coatings of phosphate PEO followed by LSA wit...
1705.00116v1
2017-05-10
Optical properties of AlGaN nanowires synthesized via ion beam techniques
AlGaN plays a vital role in hetero-structure high electron mobility transistor by employing a two-dimensional electron gas and as electron blocking layer in the multi quantum well light emitting diodes. Nevertheless, the incorporation of Al in GaN for the formation of AlGaN alloy is limited by the diffusion barrier for...
1705.03635v1
2017-05-15
Quantum Critical Behavior in the Asymptotic Limit of High Disorder: Entropy Stabilized NiCoCr0.8 Alloys
The behavior of matter near a quantum critical point (QCP) is one of the most exciting and challenging areas of physics research. Emergent phenomena such as high-temperature superconductivity are linked to the proximity to a QCP. Although significant progress has been made in understanding quantum critical behavior in ...
1705.05310v1
2018-07-14
Interface roughness, carrier localization and wave function overlap in $c$-plane InGaN/GaN quantum wells: Interplay of well width, alloy microstructure, structural inhomogeneities and Coulomb effects
In this work we present a detailed analysis of the interplay of Coulomb effects and different mechanisms that can lead to carrier localization effects in c-plane InGaN/GaN quantum wells. As mechanisms for carrier localization we consider here effects introduced by random alloy fluctuations as well as structural inhomog...
1807.05392v1
2018-09-02
Diffusion-controlled Alloying of Single-phase Multi-principal Covalent Transition Metal Carbides with Enhanced Damage tolerance and Exceptional Thermal Properties
Multicomponent alloying has displayed extraordinary potential for producing exceptional structural and functional materials. However, the synthesis of single-phase, multi-principal covalent compounds remains a challenge. Here we present a diffusion-controlled alloying strategy for the successful realization of covalent...
1810.01944v1
2018-10-05
Jacques Friedel and the physics of metals and alloys
This is an introduction to the theoretical physics of metals for students and physicists from other specialities. Certain simple consequences of the Fermi statistics in pure metals are first addressed, namely the Peierls distortion, Kohn anomalies and the Labb\'e-Friedel distortion. Then the physics of dilute alloys is...
1810.02736v1
2018-10-18
Nanomodification of aluminum alloys
NPs are ultrafine-grain crystal or amorphous substances which are as small as 100nm. They have unique physical, chemical and mechanical properties, which are very different from those of large scale materials. This uniqueness is attributed to the fact that the number of atoms in the surface layer and in the bulk is com...
1810.08025v1
2018-10-19
Monatomic Co, CoO$_2$, and CoO$_3$ Nanowires on Ir(100) and Pt(100) surfaces: Formation, Structure, and Energetics
In this study we investigate the structural and chemical changes of monatomic CoO$_2$ chains grown self-organized on the Ir(100) surface [P. Ferstl et al., PRL 117, 2016, 046101] and on Pt(100) under reducing and oxidizing conditions. By a combination of quantitative low-energy electron diffraction, scanning tunnelling...
1810.08574v1
2018-12-19
Plasmonic performance of Au$_\mathbf{x}$Ag$_\mathbf{y}$Cu$_\mathbf{1-x-y}$ alloys from many-body perturbation theory
We present a detailed appraisal of the optical and plasmonic properties of ordered alloys of the form Au$_{x}$Ag$_{y}$Cu$_{1-x-y}$, as predicted by means of first-principles many-body perturbation theory augmented by a semi-empirical Drude-Lorentz model. In benchmark simulations on elemental Au, Ag, and Cu, we find tha...
1901.00737v1
2019-01-08
Hybrid-Functional Calculations of Electronic Structure and Phase Stability of MO (M = Zn, Cd, Be, Mg, Ca, Sr, Ba) and Related Ternary Alloy M$_x$Zn$_{1-x}$O
Using the hybrid exchange-correlation functional within the density-functional theory, we have systematically investigated the structural and electronic properties of MO (M = Be, Mg, Ca, Sr, Ba, Zn, Cd) in binary rocksalt (B1), zincblende (B3) and wurtzite (B4) phases, including the structural parameters, bulk moduli, ...
1901.02226v1
2019-04-02
Mechanical properties of the magnetocaloric intermetallic LaFe11.2Si1.8 alloy at different length scales
In this work the global and local mechanical properties of the magnetocaloric intermetallic LaFe11.2Si1.8 alloy are investigated by a combination of different testing and characterization techniques in order to shed light on the partly contradictory data in recent literature. Macroscale compression tests were performed...
1904.01316v1
2019-04-11
Superconductivity in a new hexagonal high entropy alloy
High entropy alloys (HEAs) are the new class of materials with an attractive combination of tunable mechanical and physicochemical properties. They crystallize mainly in cubic structures, however, for practical applications, HEAs with hexagonal close-packed (hcp) structure are highly desirable in connection to their in...
1904.06203v1
2019-07-08
High-throughput extraction of the anisotropic interdiffusion coefficients in hcp Mg-Al alloys
A high-throughput experimental approach is presented to extract the anisotropic interdiffusion coefficient by combining information over the composition profiles obtained by the electron probe microanalysis (EPMA) and the grain orientation spectrum by the electron backscatter diffraction (EBSD) on polycrystalline diffu...
1907.03811v1
2019-10-11
Thermal conductivity of AlN, GaN, and Al$_x$Ga$_{1-x}$N alloys as a function of composition, temperature, crystallographic direction, and isotope disorder from first principles
Ultra-wide-band-gap group-III nitrides are of interest for applications in deep-ultraviolet optoelectronics and power electronics. Such devices must be able to efficiently dissipate heat generated from their operation, making the thermal conductivity of the constituent materials an important parameter for high-power ap...
1910.05440v1
2019-10-24
Solute diffusion by self-interstitial defects and radiation-induced segregation in ferritic Fe-X (X=Cr, Cu, Mn, Ni, P, Si) dilute alloys
This work investigates solute transport due to self-interstitial defects and radiation induced segregation tendencies in dilute ferritic alloys, by computing the transport coefficients of each system based on ab initio calculations of binding energies and migration rates. The implementation of the self-consistent mean ...
1910.11440v2
2014-06-28
Superdiffusive heat conduction in semiconductor alloys -- II. Truncated Lévy formalism for experimental analysis
Nearly all experimental observations of quasi-ballistic heat flow are interpreted using Fourier theory with modified thermal conductivity. Detailed Boltzmann transport equation (BTE) analysis, however, reveals that the quasi-ballistic motion of thermal energy in semiconductor alloys is no longer Brownian but instead ex...
1406.7342v2
2019-01-24
Uncertainty Analysis of Microsegregation during Laser Powder Bed Fusion
Quality control in additive manufacturing can be achieved through variation control of the quantity of interest (QoI). We choose in this work the microstructural microsegregation to be our QoI. Microsegregation results from the spatial redistribution of a solute element across the solid-liquid interface that forms duri...
1902.06785v1
2019-02-23
Multiscale dendritic needle network model of alloy solidification with fluid flow
We present a mathematical formulation of a multiscale model for solidification with convective flow in the liquid phase. The model is an extension of the dendritic needle network approach for crystal growth in a binary alloy. We propose a simple numerical implementation based on finite differences and step-wise approxi...
1902.08849v4
2019-06-12
Thermodynamic origin of solute-enriched stacking-fault in dilute Mg-Zn-Y alloys
We investigate thermodynamic behaviors of dilute Mg-Zn-Y ternary alloys to form a unique solute-enriched stacking-fault (SESF), which is an intrinsic-II type stacking-fault (I2-SF) enriched by the Zn and Y atoms and represents the structural-unit of the long-period stacking/order (LPSO) phase. SESF in the hexagonal-clo...
1906.05176v1
2019-06-18
Comparative Study of Two Multiscale Thermomechanical Models of Polycrystalline Shape Memory alloys: Application to a Representative volume Element of Titanium-Niobium
This paper presents a comparative study between two micro-macro modeling approaches to simulate stress-induced martensitic transformation in shape memory alloys (SMA). One model is a crystal plasticity based model and the other describes the evolution of the microstructure with a Boltzmann-type statistical approach. Bo...
1906.07915v1
2019-06-20
On the interaction of precipitates and tensile twins in magnesium alloys
Although magnesium alloys deform extensively through shear strains and crystallographic re-orientations associated with the growth of twins, little is known about the strengthening mechanisms associated with this deformation mode. A crystal plasticity based phase field model for twinning is employed in this work to stu...
1906.08736v2
2020-04-10
Hydrogen storage properties of Mn and Cu for Fe substitution in TiFe0.9 intermetallic compound
The present study investigates the partial substitutions of Mn and Cu for Fe in the TiFe-system to gain better understanding of the role of elemental substitution on its hydrogen storage properties. The TiFe0.88-xMn0.02Cux (x = 0, 0.02, 0.04) compositions were studied. From X-Ray Diffraction (XRD) and Electron Probe Mi...
2004.04947v2
2020-04-30
Unifying femtosecond and picosecond single-pulse magnetic switching in GdFeCo
Many questions are still open regarding the physical mechanisms behind the magnetic switching in GdFeCo alloys by single optical pulses. Phenomenological models suggest a femtosecond scale exchange relaxation between sublattice magnetization as the driving mechanism for switching. The recent observation of thermally in...
2004.14844v1
2020-05-14
Structural origin of plasticity in strained high-entropy alloy
High-entropy alloys (HEAs) are solid solutions of multiple elements with equal atomic ratios which present an innovative pathway for de novo alloy engineering. While there exist extensive studies to ascertain the important structural aspects governing their mechanical behaviors, elucidating the underlying deformation m...
2005.07088v1
2020-05-25
Effect of Dy substitution in the giant magnetocaloric properties of HoB$_{2}$
Recently, a massive magnetocaloric effect near the liquefaction temperature of hydrogen has been reported in the ferromagnetic material HoB$_{2}$. Here we investigate the effects of Dy substitution in the magnetocaloric properties of Ho$_{1-x}$Dy$_{x}$B$_{2}$ alloys ($\textit{x}$ = 0, 0.3, 0.5, 0.7, 1.0). We find that ...
2005.12000v1
2020-05-29
Direction-sensitive magnetophotonic surface crystal
Nanometer-thin rare-earth-transition metal (RE-TM) alloys with precisely controlled compositions and out-of-plane magnetic anisotropy are currently in the focus for ultrafast magnetophotonic applications. However, achieving lateral nanoscale dimensions, crucial for potential device downscaling, while maintaining design...
2005.14478v3
2020-08-09
Cutting edge of high-entropy alloy superconductors from the perspective of materials research
High-entropy alloys (HEAs) are a new class of materials which are being energetically studied around the world. HEAs are characterized by a multi-component alloy in which five or more elements randomly occupy a crystallographic site. The conventional HEA concept has developed into simple crystal structures such as face...
2008.03830v1
2020-08-13
Bulk and element specific magnetism of the medium and high entropy Cantor-Wu alloys
Magnetic Compton scattering, x-ray magnetic circular dichroism spectroscopy and bulk magnetometry measurements are performed on a set of medium (NiFeCo and NiFeCoCr) and high (NiFeCoCrPd and NiFeCoCrMn) entropy Cantor-Wu alloys. The bulk spin momentum densities determined by magnetic Compton scattering are remarkably i...
2008.05796v1
2021-03-14
Temperature dependent phase stability of Mo-Nb-Ta-W refractory high-entropy alloys
In this study Mo-Nb-Ta-W refractory high-entropy alloys (R-HEAs) have been studied for their phase stability for a wide temperature range (100 K to 2000 K). The equilibrium thermodynamic phases are determined by the changes in enthalpy and entropy. The enthalpy changes at any temperature are simulated by embedded atom ...
2103.07951v1
2022-03-03
Critical behavior of the specific heat in Ti-Si amorphous alloys at the metal-insulator transition
In this paper, we report the measurements of specific heat of an amorphous $Ti_{9.5}Si_{90.5}$ alloy located very close to the critical point of the metal-insulator transition. In the presence of a magnetic field, the specific heat is dominated by the Schottky anomaly caused by magnetic moments associated with the dang...
2203.01783v1
2022-03-10
Compositional dependence of direct transition energies in Si$_x$Ge$_{1-x-y}$Sn$_y$ alloys lattice-matched to Ge/GaAs
Si$_x$Ge$_{1-x-y}$Sn$_y$ ternary alloys are a candidate material system for use in solar cells and other optoelectronic devices. We report on the direct transition energies and structural properties of Ge-rich Si$_x$Ge$_{1-x-y}$Sn$_y$ alloys with six different compositions up to 10 % Si and 3 % Sn, lattice-matched to G...
2203.08605v1
2022-03-30
A Fast and Robust Method for Predicting the Phase Stability of Refractory Complex Concentrated Alloys using Pairwise Mixing Enthalpy
The ability to predict the composition- and temperature-dependent stability of refractory complex concentrated alloys (RCCAs) is vital to the design of high-temperature structural alloys. Here, we present a model based on first-principles calculations to predict the thermodynamic stability of multicomponent equimolar s...
2203.16002v2
2016-03-02
Near-forward Raman selection rules of the phonon-polariton created by alloying in (Zn,Be)Se
The Raman selection rules of the (ZnSe, BeSe) mixed phonon polariton created by alloying in the three mode (1ZnSe, 2BeSe) ZnBeSe system, whose dramatic S like dispersion covers the large frequency gap between the ZnSe and BeSe spectral ranges, is studied in its wave vector dependence by near forward scattering. Both th...
1603.00616v2
2017-02-10
Mechanism of Re precipitation in irradiated W-Re alloys from kinetic Monte Carlo simulations
High-temperature, high-dose, neutron irradiation of W results in the formation of Re-rich clusters at concentrations one order of magnitude lower than the thermodynamic solubility limit. These clusters may eventually transform into brittle W-Re intermetallic phases, which can lead to high levels of hardening and therma...
1702.03019v1
2017-06-13
Structural ordering of laser-processed FePdCu thin alloy films
The Cu/Fe/Pd multilayers were transformed into L10-ordered FePdCu alloy by pulsed laser annealing. The initial multilayers were irradiated with 1, 10, 100, and 1000 laser pulses with duration time of 10 ns and energy density of 235 mJ/cm2. The gradual change of the number of laser pulses allowed to investigate the stru...
1706.03918v1
2017-10-09
Crystallographic features of the approximant H (Mn$_7$Si$_2$V) phase in the Mn-Si-V alloy system
The intermetallic compound H (Mn$_7$Si$_2$V) phase in the Mn-Si-V alloy system can be regarded as an approximant phase of the dodecagonal quasicrystal as one of the two-dimensional quasicrystals. To understand the features of the approximant H phase, in this study, the crystallographic features of both the H phase and ...
1710.02929v1
2017-10-24
Valence band-anticrossing in GaP$_{1-x}$Bi$_{x}$ dilute bismide alloys: giant bowing of the band gap and spin-orbit splitting energy
Using spectroscopic ellipsometry measurements on GaP$_{1-x}$Bi$_{x}$/GaP epitaxial layers up to $x = 3.7$% we observe a giant bowing of the direct band gap ($E_{g}^{\Gamma}$) and valence band spin-orbit splitting energy ($\Delta_{\textrm{SO}}$). $E_{g}^{\Gamma}$ ($\Delta_{\textrm{SO}}$) is measured to decrease (increas...
1710.08995v1
2019-03-13
Structure and electronic properties of the ($\sqrt{3}\times \sqrt{3}$)$R30^{\circ}$ SnAu$_2$/Au(111) surface alloy
We have investigated the atomic and electronic structure of the ($\sqrt{3}\times \sqrt{3}$)$R30^{\circ}$ SnAu$_2$/Au(111) surface alloy. Low energy electron diffraction and scanning tunneling microscopy measurements show that the native herringbone reconstruction of bare Au(111) surface remains intact after formation o...
1903.05484v1
2019-05-28
The role of dwell hold on the dislocation mechanisms of fatigue in a near alpha titanium alloy
The dislocation structures appearing in highly mis-oriented soft/hard grain pairs in near-alpha titanium alloy Ti6242Si were examined with and without the application of load holds (dwell) during fatigue. Dislocation pile-up in a soft grain resulted in internal stresses in an adjacent hard grain which could be relaxed ...
1905.11714v2
2019-08-07
Part I: Theoretical Predictions of Preferential Oxidation in Refractory High Entropy Materials
High entropy materials, which include high entropy alloys, carbides, and borides, are a topic of substantial research interest due to the possibility of a large number of new material compositions that could fill gaps in application needs. There is a current need for materials exhibiting high temperature stability, par...
1908.02654v2
2019-08-10
Robust data-driven approach for predicting the configurational energy of high entropy alloys
High entropy alloys (HEAs) have been increasingly attractive as promising next-generation materials due to their various excellent properties. It's necessary to essentially characterize the degree of chemical ordering and identify order-disorder transitions through efficient simulation and modeling of thermodynamics. I...
1908.03665v1
2019-08-11
Al-Cu-Fe alloys: the relationship between the quasicrystal and its melt
Understanding the mechanisms which relate properties of liquid and solid phases is crucial for fabricating new advanced solid materials, such as glasses, quasicrystals and high-entropy alloys. Here we address this issue for quasicrystal-forming Al-Cu-Fe alloys which can serve as a model for studying microscopic mechani...
1908.03931v1
2019-08-21
Electronic interaction of slow hydrogen and helium ions in the nickel-silicon system
Electronic stopping cross sections (SCS) of nickel, silicon and nickel-silicon alloys for protons and helium (He) ions are studied in the regime of medium and low energy ion scattering, i.e., for ion energies in the range from 500 eV to 200 keV. For protons, at velocities below the Bohr velocity the deduced SCS is prop...
1908.07767v1
2019-08-22
Strain heterogeneity and micro-damage nucleation under tensile stresses in an Mg-5Al-3Ca alloy with an intermetallic skeleton
Strain heterogeneity at the microstructural level plays a vital role in the deformation and fracture behaviour of dual or multi-phase materials. In the present work, the strain heterogeneity, localization and partitioning arising at the sub-micron scale during elevated temperature (170 {\deg}C) tensile deformation of a...
1908.08271v1
2019-09-19
Design of reversible low-field magnetocaloric effect at room temperature in hexagonal MnMX ferromagnets
Giant magnetocaloric effect is widely achieved in hexagonal MnMX-based (M = Co or Ni, X = Si or Ge) ferromagnets at their first-order magnetostructural transition. However, the thermal hysteresis and the low sensitivity of the magnetostructural transition to the magnetic field inevitably lead to a sizeable irreversibil...
1909.08836v1
2019-12-13
Strength, transformation toughening and fracture dynamics of rocksalt-structure Ti1-xAlxN (0 <= x <= 0.75) alloys
Ab initio-calculated ideal strength and toughness describe the upper limits for mechanical properties attainable in real systems and can, therefore, be used in selection criteria for materials design. We employ density-functional ab initio molecular dynamics (AIMD) to investigate the mechanical properties of defect-fre...
1912.06367v2
2019-12-14
Spin-mediated charge-to-heat current conversion phenomena in ferromagnetic binary alloys
Spin-mediated charge-to-heat current conversion phenomena, i.e., the anomalous Ettingshausen effect (AEE) and the anisotropic magneto-Peltier effect (AMPE), have been investigated in various ferromagnetic Ni-Fe, Ni-Pt, Ni-Pd, and Fe-Pt binary alloys at room temperature. When a charge current is applied to a ferromagnet...
1912.06799v2
2019-12-20
Theory-training deep neural networks for an alloy solidification benchmark problem
Deep neural networks are machine learning tools that are transforming fields ranging from speech recognition to computational medicine. In this study, we extend their application to the field of alloy solidification modeling. To that end, and for the first time in the field, theory-trained deep neural networks (TTNs) f...
1912.09800v1
2019-12-23
RSAVS superconductors: materials with a superconducting state that is robust against large volume shrinkage
TThe transition temperature (TC) between normal and superconducting states usually exhibits a dramatic increase or decrease with increasing applied pressure. Here we present, in contrast, a new kind of superconductor that exhibits the exotic feature that TC is robust against large volume shrinkages induced by applied p...
1912.10794v2