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2016-12-22
Microstructure Representation and Reconstruction of Heterogeneous Materials via Deep Belief Network for Computational Material Design
Integrated Computational Materials Engineering (ICME) aims to accelerate optimal design of complex material systems by integrating material science and design automation. For tractable ICME, it is required that (1) a structural feature space be identified to allow reconstruction of new designs, and (2) the reconstructi...
1612.07401v3
2017-02-05
Spin-Diffusions and Diffusive Molecular Dynamics
Metastable condensed matter typically fluctuates about local energy minima at the femtosecond time scale before transitioning between local minima after nanoseconds or microseconds. This vast scale separation limits the applicability of classical molecular dynamics methods and has spurned the development of a host of a...
1702.01469v4
2017-02-10
Reliable thermodynamic estimators for screening multicaloric materials
Reversible, diffusionless, first-order solid-solid phase transitions accompanied by caloric effects are critical for applications in the solid-state cooling and heat-pumping devices. Accelerated discovery of caloric materials requires reliable but faster estimators for predictions and high-throughput screening of syste...
1702.03042v6
2017-02-16
Multiscale modelling of the morphology and spatial distribution of θ' precipitates in Al-Cu alloys
A multiscale approach based on the phase-field model is developed to simulate homogeneous and heterogeneous formation of {\theta}' precipitates during high temperature ageing in Al-Cu alloys. The model parameters that determine the different energy contributions (chemical free energy, interfacial energy, lattice parame...
1702.05020v2
2017-06-14
The impact of the halide cage on the electronic properties of fully inorganic caesium lead halide perovskites
Perovskite solar cells with record power conversion efficiency are fabricated by alloying both hybrid and fully inorganic compounds. While the basic electronic properties of the hybrid perovskites are now well understood, key electronic parameters for solar cell performance, such as the exciton binding energy of fully ...
1706.04489v1
2017-10-09
Possible nucleus of the Bergman cluster in the Zn-Mg-Y alloy system
To understand the formation of the Bergman cluster in the F-type icosahedral quasicrystal, crystallographic relations between the quasicrystal and the intermetallic-compound H and Zn$_{23}$Y$_6$ phases in the Zn-Mg-Y alloy system were investigated mainly by transmission electron microscopy. It was found that, although ...
1710.02941v1
2017-10-10
Multiple scattering theory for polycrystalline materials with strong grain anisotropy: theoretical fundamentals and applications
This work is a natural extension of the authors previous work, Multiple scattering theory for heterogeneous elastic continua with strong property fluctuation, theoretical fundamentals and applications, which established the foundation for developing multiple scattering model for strongly scattering heterogeneous elasti...
1710.03828v1
2017-10-20
Amorphous, ultra-nano- and nano-crystalline tungsten-based coatings grown by Pulsed Laser Deposition: mechanical characterization by Surface Brillouin Spectroscopy
Pulsed Laser Deposition allows to obtain W and W-Ta alloy coatings with different nanostructures, monitored by X-ray diffraction. The correlation between such structures and the elastic properties is investigated for amorphous-like, ultra-nano- and nano-crystalline coatings obtained by tuning the gas pressure during de...
1710.07581v2
2018-04-15
On the origin of incoherent magnetic exchange coupling in MnBi/Fe$_x$Co$_{1-x}$ bilayer system
In this study we investigate the exchange coupling between the hard magnetic compound MnBi and the soft magnetic alloy FeCo including the interface structure between the two phases. Exchange spring MnBi-Fe$_x$Co$_{1-x}$ (x = 0.65 and 0.35) bilayers with various thicknesses of the soft magnetic layer were deposited onto...
1804.05383v2
2018-04-23
Homogenization of Halide Distribution and Carrier Dynamics in Alloyed Organic-Inorganic Perovskites
Perovskite solar cells have shown remarkable efficiencies beyond 22%, through organic and inorganic cation alloying. However, the role of alkali-metal cations is not well-understood. By using synchrotron-based nano-X-ray fluorescence and complementary measurements, we show that when adding RbI and/or CsI the halide dis...
1804.08722v2
2019-03-06
A three-dimensional constitutive model for the martensitic transformation in polycrystalline shape memory alloys under large deformation
This work presents a three-dimensional constitutive model for the martensitic transformation in polycrystalline Shape Memory Alloys (SMAs) under large deformation. By utilizing the logarithmic strain and rate, the model is able to account for large strains and rotations that SMA-based components may undertake, but also...
1903.02187v1
2019-05-10
Towards Obtaining 2D and 3D and 1D PtPN with Pentagonal Pattern
We apply an alloying strategy to single-layer PtN$_2$ and PtP$_2$, aiming to obtain a single-layer Pt-P-N alloy with a relatively low formation energy with reference to its bulk structure. We perform structure search based on a cluster-expansion method and predict single-layer and bulk PtPN consisting of pentagonal net...
1905.03973v1
2019-05-20
Segregation--Assisted Spinodal and Transient Spinodal Phase Separation at Grain Boundaries
Segregation to grain boundaries affects their cohesion, corrosion and embrittlement and plays a critical role in heterogeneous nucleation. In order to quantitatively study segregation and phase separation at grain boundaries, we derive a density-based phase-field model. In this model, we describe the grain boundary fre...
1905.07970v2
2019-05-24
Analytical study on phase transition of shape memory alloy wire under uniaxial tension
This paper considers the stress-induced phase transitions of shape memory alloy slender cylinder, and analytically studies the phase transition process and the associated instability. A three-dimensional (3D) phenomenological model with an internal variable is adopted, which is simplified to a 1D system of two strains ...
1905.10454v2
2019-05-30
Sr-induced dipole scatter in BST: Insights from MD simulations using a transferable bond valence-based interatomic potential
In order to design next-generation ferroelectrics, a microscopic understanding of their macroscopic properties is critical. One means to achieving an atomistic description of ferroelectric and dielectric phenomena is classical molecular dynamics simulations. Previously, we have shown that interatomic potentials based o...
1905.13201v1
2019-08-09
Spontaneous formation of thermodynamically stable Al--Cu--Fe icosahedral quasicrystal from realistic atomistic simulations
Icosahedral quasicrystals spontaneously form from the melt in simulations of Al--Cu--Fe alloys. We model the interatomic interactions using oscillating pair potentials tuned to the specific alloy system based on a database of density functional theory (DFT)-derived energies and forces. Favored interatomic separations a...
1908.03417v1
2019-09-19
Entropic Geometrodynamics of Quantum Particles
Quantum Mechanics will be derived here in a different way. It will be derived from a new conformal gravity theory that is postulated to apply at Planck scale and uses Wheeler's notion of a quantum foam in the description of spacetime at Planck scale. The new gravity theory will also be used as the basis of a new geomet...
1909.09133v16
2019-09-26
Influence of simple metals on the stability of $\langle a\rangle$ basal screw dislocations in hexagonal titanium alloys
Basal slip acts as a secondary deformation mode in hexagonal close-packed titanium and becomes one of the primary mechanisms in titanium alloyed with simple metals. As these solute elements also lead to a pronounced reduction of the energy of the basal stacking fault, one can hypothesize that they promote basal dissoci...
1909.12010v1
2019-12-19
Grain boundary diffusion and grain boundary structures of a Ni-Cr-Fe-alloy: Evidences for grain boundary phase transformations
Grain boundary tracer diffusion of Ni, Fe and Cr was studied in a Ni-base 602CA coarse-grained alloy. A co-existence of several short-circuit contributions was distinguished at higher temperatures in Harrison's B-type regime (773-873 K), which were related to different families of high-angle grain boundaries with disti...
1912.09184v1
2020-02-06
High Entropy Alloy Nanoparticles Decorated, p-type 2D-Molybdenum Disulphide (MoS2) and Gold Schottky Junction Enhanced Hydrogen Sensing
Molybdenum Disulphide (MoS2) is an interesting material which exists in atomically thin multilayers and can be exfoliated into monolayer or a few layers for multiple applications. It has emerged as a promising material for development of such efficient sensors. Here, we have exfoliated and decorated MoS2 flakes with no...
2002.02366v1
2020-03-03
Dislocation pipe diffusion and solute segregation during the growth of metastable GeSn
Controlling the growth kinetics from the vapor phase has been a powerful paradigm enabling a variety of metastable epitaxial semiconductors such as Sn-containing group IV semiconductors (Si)GeSn. In addition to its importance for emerging photonic and optoelectronic applications, this class of materials is also a rich ...
2003.01308v1
2020-02-27
MLography: An Automated Quantitative Metallography Model for Impurities Anomaly Detection using Novel Data Mining and Deep Learning Approach
The micro-structure of most of the engineering alloys contains some inclusions and precipitates, which may affect their properties, therefore it is crucial to characterize them. In this work we focus on the development of a state-of-the-art artificial intelligence model for Anomaly Detection named MLography to automati...
2003.04226v1
2020-03-17
Anomalous critical point behavior in dilute magnetic semiconductor (Ca,Na)(Zn,Mn)2Sb2
In this paper we report successful synthesis and magnetic properties of (Ca,Na)(Zn,Mn)2Sb2 as a new ferromagnetic dilute magnetic semiconductor (DMS). In this DMS material the concentration of magnetic moments can be controlled independently from the concentration of electric charge carriers that are required for media...
2003.07617v3
2020-03-19
Native point defects and low $p$-doping efficiency in $Mg_2 (Si,Sn)$ solid solutions: A hybrid-density functional study
We perform hybrid-density functional calculations to investigate the charged defect formation energy of native point defects in $Mg_2 Si$, $Mg_2 Sn$, and their solid solutions. The band gap correction by hybrid-density functional is found to be critical to determine the charged defect density in these materials. For $M...
2003.08886v2
2020-03-21
Solidification Characteristics of Laser-Powder Bed Fused AlSi10Mg: Role of Building Direction
In this work, the effect of building direction on the microstructure evolution of laser-powder bed fusion (LPBF) processed AlSi10Mg alloy was investigated. The building direction, as shown in experimentally fabricated parts, can influence the solidification behavior and promote morphological transitions in cellular den...
2003.09757v1
2020-03-23
Grain boundary diffusion in CoCrFeMnNi high entropy alloy: kinetic hints towards a phase decomposition
Grain boundary self-diffusion of $^{57}$Co, $^{51}$Cr, $^{59}$Fe and $^{54}$Mn in a coarse-grained, single-phase fcc CoCrFeMnNi high entropy alloy is measured in a wide temperature range of 643 to 1273~K in both C- and B-type kinetic regimes after Harrison's classification. The results suggest that the product of the p...
2003.10157v2
2020-03-31
Multiple- to single-gap superconductivity crossover in Nb$_5$Ir$_{3-x}$Pt$_x$O alloys
By using mostly the muon-spin rotation/relaxation ($\mu$SR) technique, we investigate the superconductivity (SC) of Nb$_5$Ir$_{3-x}$Pt$_x$O ($x = 0$ and 1.6) alloys, with $T_c = 10.5$ K and 9.1 K, respectively. At a macroscopic level, their superconductivity was studied by electrical resistivity, magnetization, and spe...
2003.14033v1
2020-06-01
Surface structures of the magnetostrictive D03-Fe3Ga(001)
First-principles total energy calculations and experimental measurements were performed to study the surface reconstructions of the magnetostrictive Fe3Ga alloy. The magnetostrictive behavior was evaluated in the bulk by compressing and stretching its lattice parameter. Results demonstrate two thermodynamically stable ...
2006.00647v1
2020-06-02
Ti alloyed $α$-Ga$_2$O$_3$: route towards wide band gap engineering
The suitability of Ti as a band gap modifier for $\alpha$-Ga$_2$O$_3$ was investigated, taking advantage of the isostructural {\alpha}-phases and high band gap difference between Ti$_2$O$_3$ and Ga$_2$O$_3$. Films of Ti:Ga$_2$O$_3$, with a range of Ti concentrations, synthesized by atomic layer deposition on sapphire s...
2006.01422v1
2020-06-13
Cyclic Re-austenitization of Copper-bearing High-Strength Low-Alloy Steels Fabricated by Laser Powder Bed Fusion
For the first time, cyclic re-austenitization is carried out for additively manufactured high-strength low-alloy (HSLA) steels in order to refine the microstructure by reducing the prior austenite grain (PAG) size. In this work, HSLA-100 steels processed using laser powder bed fusion (LPBF) technique are subjected to s...
2006.07552v1
2020-06-19
Characterising Ion-Irradiated FeCr: Hardness, Thermal Diffusivity and Lattice Strain
Ion-irradiated FeCr alloys are useful for understanding and predicting neutron-damage in the structural steels of future nuclear reactors. Previous studies have largely focused on the structure of irradiation-induced defects, probed by transmission electron microscopy (TEM), as well as changes in mechanical properties....
2006.11073v2
2020-06-22
Tunable band-gap and isotropic light absorption from bismuth-containing GaAs core$-$shell and multi$-$shell nanowires
Semiconductor core$-$shell nanowires based on the GaAs substrate are building blocks of many photonic, photovoltaic and electronic devices, thanks to the associated direct band-gap and the highly tunable optoelectronic properties. The selection of a suitable material system is crucial for custom designed nanowires tail...
2006.12108v1
2020-06-28
Mechanical Evaluation Of Selective Laser Melted Ni-Rich Niti: Compression, Tension, And Torsion
Two unique behaviors of superelasticity and shape memory effect have made shape memory alloy such as NiTi, an interesting alloy for different applications. Recently, additive manufacturing (AM) as a powerful tool for fabricating NiTi has become of interest to make complex geometries. Selective laser melting (SLM) is an...
2006.15659v1
2020-06-27
Tusas: A fully implicit parallel approach for coupled phase-field equations
We develop a fully-coupled, fully-implicit approach for phase-field modeling of solidification in metals and alloys. Predictive simulation of solidification in pure metals and metal alloys remains a significant challenge in the field of materials science, as microstructure formation during the solidification process pl...
2006.16764v2
2020-06-30
Growth kinetics and atomistic mechanisms of native oxidation of ZrS$_x$Se$_{2-x}$ and MoS$_2$ crystals
A thorough understanding of native oxides is essential for designing semiconductor devices. Here we report a study of the rate and mechanisms of spontaneous oxidation of bulk single crystals of ZrS$_x$Se$_{2-x}$ alloys and MoS$_2$. ZrS$_x$Se$_{2-x}$ alloys oxidize rapidly, and the oxidation rate increases with Se conte...
2007.00117v3
2020-08-31
Intermediate energy proton irradiation: rapid, high-fidelity materials testing for fusion and fission energy systems
Fusion and advanced fission power plants require advanced nuclear materials to function under new, extreme environments. Understanding the evolution of mechanical and functional properties during radiation damage is essential to the design and commercial deployment of these systems. The shortcomings of existing methods...
2009.00048v2
2020-09-03
First principles analysis of precipitation in Mg-Zn alloys
Precipitation in Mg-Zn alloys was analyzed by means of first principles calculations. Formation energies of symmetrically distinct hcp Mg1-xZnx (0 < x < 1) configurations were determined and potential candidates for Guinier-Preston zones coherent with the matrix were identified from the convex hull. The most likely str...
2009.01892v1
2020-09-07
Multi-scale modeling of the effects of temperature, radiation flux and sink strength on point-defect and solute redistribution in dilute Fe-based alloys
In this work, we investigate the radiation-induced segregation (RIS) resulting from the coupling between the atomic and point defect (PD) fluxes towards the structural defects of the microstructure. This flux coupling depends on the migration mechanisms of PDs and atoms, including thermal diffusion mechanisms and force...
2009.02971v1
2020-09-23
Chemical Interaction and Electronic Structure in a Compositionally Complex Alloy: a Case Study by means of X-ray Absorption and X-ray Photoelectron Spectroscopy
Chemical interaction and changes in local electronic structure of Cr, Fe, Co, Ni and Cu transition metals (TMs) upon formation of an $Al_{8}Co_{17}Cr_{17}Cu_{8}Fe_{17}Ni_{33}$ compositionally complex alloy (CCA) have been studied by X-ray absorption spectroscopy and X-ray photoelectron spectroscopy. It was found that u...
2009.11398v1
2020-09-28
Mapping the Structure of Oxygen-Doped Wurtzite Aluminum Nitride Coatings From Ab Initio Random Structure Search and Experiments
Machine learning is changing how we design and interpret experiments in materials science. In this work, we show how unsupervised learning, combined with ab initio modeling, improves our understanding of structural metastability in multicomponent alloys. We use the example case of Al-O-N alloys where the formation of a...
2009.13186v2
2020-10-01
A Thermochemical Database from High-throughput First-Principles Calculations and Its Application to Analyzing Phase Evolution in AM-fabricated IN718
A comprehensive thermochemical database is constructed based on high-throughput first-principles phonon calculations of over 3000 atomic structures in Ni, Fe, and Co alloys involving a total of 26 elements including Al, B, C, Cr, Cu, Hf, La, Mn, Mo, N, Nb, O, P, Re, Ru, S, Si, Ta, Ti, V, W, Y, and Zr, providing thermoc...
2010.00660v1
2020-10-08
High tunnel magnetoresistance and magnetism in metastable bcc Co$_{1-x}$Mn$_x$-based magnetic tunnel junctions
Co-rich Co$_{1-x}$Mn$_x$ alloys have hcp or fcc disordered phases and those ferromagnetic orderings are significantly deteriorated with increasing Mn concentration $x$ in bulk. On the other hand, those metastable bcc phases show properties attractive to spintronics, e.g., high tunnel magnetoresistance (TMR) ratio of mo...
2010.03775v1
2020-10-08
Microstructure, mechanical properties, corrosion resistance and cytocompatibility of WE43 Mg alloy scaffolds fabricated by laser powder bed fusion for biomedical applications
Open-porous scaffolds of WE43 Mg alloy with a body-center cubic cell pattern were manufactured by laser powder bed fusion with different strut diameters. The geometry of the unit cells was adequately reproduced during additive manufacturing and the porosity within the struts was minimized. The microstructure of the sca...
2010.03812v1
2020-10-08
Excited-state dynamics of structurally characterized crystal of SnxSb1-x
The topological behavior of heavy metal alloys opens a vast area for incredible research and future technology. Here, we extend our previous report about the superconducting properties of Sn0.4Sb0.6 along with the compositional variation of Sn and Sb in SnxSb1-x (with (X=0.5 and 0.6)) to study the detailed optical prop...
2010.03942v1
2020-10-09
Phase field modelling of fracture and fatigue in Shape Memory Alloys
We present a new phase field framework for modelling fracture and fatigue in Shape Memory Alloys (SMAs). The constitutive model captures the superelastic behaviour of SMAs and damage is driven by the elastic and transformation strain energy densities. We consider both the assumption of a constant fracture energy and th...
2010.04390v1
2020-10-09
Metal (boro-) hydrides for high energy density storage and relevant emerging technologies
The current energy transition imposes a rapid implementation of energy storage systems with high energy density and eminent regeneration and cycling efficiency. Metal hydrides are potential candidates for generalized energy storage, when coupled with fuel cell units and/or batteries. An overview of ongoing research is ...
2010.04432v1
2020-10-26
Mechanisms of Ti3Al precipitation in hcp alpha-Ti
Nucleation and growth of Ti$_3$Al \textalpha{}$_2$ ordered domains in \textalpha{}-Ti--Al--X alloys were characterised using a combination of transmission electron microscopy, atom probe tomography and small angle X-ray scattering. Model alloys based on Ti--7Al~(wt.\%) and containing O, V and Mo were aged at \SI{550}{\...
2010.13894v3
2020-10-29
Domain wall dynamics in antiferromagnetically-coupled double-lattice systems
In ferromagnetic materials, the rich dynamics of magnetic domain walls (DWs) under magnetic field or current have been successfully described using the well-known q-{\phi} analytical model. We demonstrate here that this simple unidimensional model holds for multiple-sublattice materials such as ferrimagnetic alloys or ...
2010.15443v1
2020-11-02
Monte Carlo simulation of order-disorder transition in refractory high entropy alloys: a data-driven approach
High entropy alloys (HEAs) are a series of novel materials that demonstrate many exceptional mechanical properties. To understand the origin of these attractive properties, it is important to investigate the thermodynamics and elucidate the evolution of various chemical phases. In this work, we introduce a data-driven ...
2011.00698v1
2020-11-24
High-Capacity High-Power Thermal Energy Storage Using Solid-Solid Martensitic Transformations
Adding thermal conductivity enhancements to increase thermal power in solid-liquid phase-change thermal energy storage modules compromises volumetric energy density and often times reduces the mass and volume of active phase change material (PCM) by well over half. In this study, a new concept of building thermal energ...
2011.12339v1
2020-12-07
All-optical helicity-independent switching state diagram in GdFeCo alloys
Ultra-fast magnetization switching induced by a single femtosecond laser pulse, under no applied magnetic field has attracted a lot of attention during the last 10 years because of its high potential for low energy and ultra-fast memory applications. Single-pulse helicity-independent switching has mostly been demonstra...
2012.03504v2
2020-12-16
Ultrahigh Green and Red Optical Gain Cross-sections from Solutions of Colloidal Quantum Well Heterostructures
Optical gain in solution, which provides high photostability as a result of continuous regeneration of the gain medium, is extremely attractive for optoelectronic applications. Here, we propose and demonstrate amplified spontaneous emission (ASE) in solution with ultralow thresholds of 30 mikroJ/cm2 in red and of 44 mi...
2012.09236v1
2020-12-12
Decoding Grain Boundary Thermodynamics in High-Entropy Alloys in a 5D Space: Coupled Segregation and Disordering
Grain boundaries (GBs) can critically influence the microstructural evolution and various materials properties. However, a fundamental understanding of GBs in high-entropy alloys (HEAs) is lacking because of the complex couplings of the segregations of multiple elements and interfacial disordering, which can generate n...
2012.12865v4
2021-01-10
Prediction of Stable Ground-State Binary Sodium-Potassium Interalkalis under High Pressures
The complex structures and electronic properties of alkali metals and their alloys provide a natural laboratory for studying the interelectronic interactions of metals under compression. A recent theoretical study (J. Phys. Chem. Lett. 2019, 10, 3006) predicted an interesting pressure-induced decomposition-recombinatio...
2101.03459v1
2021-01-20
Probing Lattice Dynamics and Electronic Resonances in Hexagonal Ge and SixGe1-x Alloys in Nanowires by Raman Spectroscopy
Recent advances in nanowire synthesis have enabled the realization of crystal phases that in bulk are attainable only under extreme conditions, i.e. high temperature and/or high pressure. For group IV semiconductors this means access to hexagonal-phase SixGe1-x nanostructures (with a 2H type of symmetry), which are pre...
2101.08207v1
2021-01-04
Understanding and formalization of the fretting-wear behavior of a cobalt-based alloy at high temperature
The purpose of this study is to investigate the mechanisms involved in the wear of cobalt-based interfaces at high temperature. The studied contact is a cobalt-based alloy subjected to fretting against an alumina sample. At high temperature, a protective third body is spontaneously created at the interface and presents...
2101.10065v1
2021-02-03
Collapse of quasiparticle multiplets and $5f$ itinerant-localized crossovers in cubic phase Pu$_{3}$Ga
The physical properties of plutonium and plutonium-based intermetallic compounds are extremely sensitive to temperature, pressure, and chemical alloying. A celebrated example is the high-temperature $\delta$ phase plutonium, which can be stabilized at room temperature by doping it with a few percent trivalent metal imp...
2102.02034v1
2021-02-04
Lattice dynamics effects on finite-temperature stability of $R_{1-x}$Fe$_{x}$ ($R$ = Y, Ce, Nd, Sm, and Dy) alloys from first principles
We report the effects of lattice dynamics on thermodynamic stability of binary $R_{1-x}$Fe$_x$ $(0<x<1)$ compounds ($R$: rare-earth elements, Y, Ce, Nd, Sm, and Dy) at finite temperature predicted by first-principles calculation based on density functional theory (DFT). We first demonstrate that the thermodynamic stabi...
2102.02590v1
2021-02-11
Noncentrosymmetric topological Dirac semimetals in three dimensions
Topological Dirac semimetals are a class of semimetals that host symmetry-protected Dirac points near the Fermi level, which arise due to a band inversion of the conduction and valence bands. In this work, we study the less explored class of \emph{noncentrosymmetric} topological Dirac semimetals in three dimensions. We...
2102.05828v2
2021-02-17
Mechanical behavior of high-entropy alloys: A review
High-entropy alloys (HEAs) are materials that consist of equimolar or near-equimolar multiple principal components but tend to form single phases, which is a new research topic in the field of metallurgy, have attracted extensive attention in the past decade. The HEAs families contain the face-centered-cubic (fcc), bod...
2102.09055v1
2021-02-22
Efficient and quantitative phase field simulations of polycrystalline solidification using a vector order parameter
A vector order parameter phase field model derived from a grand potential functional is presented as a new approach for modeling polycrystalline solidification of alloys. In this approach, the grand potential density is designed to contain a discrete set of finite wells, a feature that naturally allows for the growth a...
2102.11015v1
2021-02-16
Convolutional neural network-assisted recognition of nanoscale L12 ordered structures in face-centred cubic alloys
Nanoscale L12-type ordered structures are widely used in face-centred cubic (FCC) alloys to exploit their hardening capacity and thereby improve mechanical properties. These fine-scale particles are typically fully coherent with matrix with the same atomic configuration disregarding chemical species, which makes them c...
2102.11024v1
2021-02-24
Bragg Coherent Imaging of nanoprecipitates: role of superstructure reflections
Coherent precipitation of ordered phases is responsible for providing exceptional high temperature mechanical properties in a wide range of compositionally complex alloys (CCAs). Ordered phases are also essential to enhance the magnetic or catalytic properties of alloyed nanoparticles. The present work aims at demonstr...
2102.12269v1
2021-04-21
Effective structural unit analysis in hexagonal close packed alloys -- reconstruction of parent beta microstructures & crystal orientation post processing analysis
Materials with an allotropic phase transformation can result in the formation of microstructures where grains have orientation relationships (ORs) determined by the transformation history. These microstructures influence the final material properties. In zirconium alloys, there is a solid-state body centred cubic (BCC)...
2104.10648v2
2021-04-29
The dominance of non-electron-phonon charge carrier interaction in highly-compressed superhydrides
The primary mechanism governing the emergence of near-room-temperature superconductivity in superhydrides is widely accepted to be the electron-phonon interaction. If so, the temperature dependent resistance, R(T), in these materials should obey the Bloch-Gr\"uneisen equation, where the power-law exponent, p, should be...
2104.14145v3
2021-04-29
The dynamic evolution of swelling in nickel concentrated solid solution alloys through in situ property monitoring
Defects and microstructural features spanning the atomic level to the microscale play deterministic roles in the expressed properties of materials. Yet studies of material evolution in response to environmental stimuli most often correlate resulting performance with one dominant microstructural feature only. Here, the ...
2104.14576v4
2021-05-11
Gaussian graphical models with graph constraints for magnetic moment interaction in high entropy alloys
This article is motivated by studying the interaction of magnetic moments in high entropy alloys (HEAs), which plays an important role in guiding HEA designs in materials science. While first principles simulations can capture magnetic moments of individual atoms, explicit models are required to analyze their interacti...
2105.05280v1
2021-05-31
Understanding creep of a single-crystalline Co-Al-W-Ta superalloy by studying the deformation mechanism, segregation tendency and stacking fault energy
A systematic study of the compression creep properties of a single-crystalline Co-base superalloy (Co-9Al-7.5W-2Ta) was conducted at 950 {\deg}C, 975 {\deg}C and 1000 {\deg}C to reveal the influence of temperature and the resulting diffusion velocity of solutes like Al, W and Ta on the deformation mechanisms. Two creep...
2105.14725v2
2021-05-31
Ab initio Molecular Dynamics Simulation of Threshold Displacement Energies and Defect Formation Energies in Y4Zr3O12
Ab initio molecular dynamics simulations using VASP was employed to calculate threshold displacement energies and defect formation energies of Y4Zr3O12 {\delta}-phase, which is the most commonly found phase in newly developed Zr and Al-containing ODS steels. The Threshold displacement energy (Ed) values are determined ...
2105.15066v1
2021-06-09
Amorphous alloys surpass E/10 strength limit at extreme strain rates
Theoretical predictions of the ideal strength of materials range from E/30 to E/10 (E is Young's modulus). However, despite intense interest over the last decade, the value of the ideal strength that can be attained experimentally for metals remains a mystery (1-5). In this study, we demonstrated the unprecedented stre...
2106.04875v3
2021-06-23
Cold dwell behaviour of Ti$_6$Al alloy: Understanding load shedding using digital image correlation and crystal plasticity simulations
Digital image correlation (DIC) and crystal plasticity simulation were utilised to study cold dwell behaviour in a coarse grain Ti-6Al alloy at 3 different temperatures up to 230 C. Strains extracted from large volume grains were measured during creep by DIC and were used to calibrate the crystal plasticity model. The ...
2106.12227v1
2021-06-25
Identifying outstanding transition-metal-alloy heterogeneous catalysts for the oxygen reduction and evolution reactions via subgroup discovery
In order to estimate the reactivity of a large number of potentially complex heterogeneous catalysts while searching for novel and more efficient materials, physical as well as data-centric models have been developed for a faster evaluation of adsorption energies compared to first-principles calculations. However, glob...
2106.13522v1
2021-08-04
Phase-Field Modelling of Transformation Pathways and Microstructural Evolution in Multi-Principal Element Alloys
The recently developed refractory multi-principle element alloy (MPEA), AlMo$_{0.5}$NbTa$_{0.5}$TiZr, shows an interesting microstructure with cuboidal precipitates of a disordered phase (${\beta}$, bcc) coherently embedded in an ordered phase (${\beta}'$, B2) matrix, unlike the conventional Ni-based superalloys where ...
2108.02071v3
2021-08-12
Phase Classification of Multi-Principal Element Alloys via Interpretable Machine Learning
There is intense interest in uncovering design rules that govern the formation of various structural phases as a function of chemical composition in multi-principal element alloys (MPEAs). In this paper, we develop a machine learning (ML) approach built on the foundations of ensemble learning, post hoc model interpreta...
2108.05933v1
2021-08-18
High Entropy Alloy CrFeNiCoCu sputtered films
High entropy alloy(HEA) films of CrFeCoNiCu were prepared by sputtering, their structure was characterized, and their electric properties measured by temperature dependent Hall and Seebeck measurement. The HEA films show a solid solution with fcc structure, and a 111 texture with columnar grains of widths 15-30 nm exte...
2108.08373v2
2021-08-26
Infrared dielectric functions and Brillouin zone center phonons of $α$-Ga$_2$O$_3$ compared to $α$-Al$_2$O$_3$
We determine the anisotropic dielectric functions of rhombohedral $\alpha$-Ga$_2$O$_3$ by far-infrared and infrared generalized spectroscopic ellipsometry and derive all transverse optical and longitudinal optical phonon mode frequencies and broadening parameters. We also determine the high frequency and static dielect...
2108.12058v1
2021-09-08
Coherent spin rotation-induced zero thermal expansion in MnCoSi-based spiral magnets
Materials exhibiting zero thermal expansion (ZTE), namely, volume invariance during temperature change, can resist thermal shock and are highly desired in modern industries as high-precision components. However, pure ZTE materials are rare, especially those that are metallic. Here, we report the discovery of a pure met...
2109.03557v1
2021-09-22
Data-Driven Design of Novel Halide Perovskite Alloys
The great tunability of the properties of halide perovskites presents new opportunities for optoelectronic applications as well as significant challenges associated with exploring combinatorial chemical spaces. In this work, we develop a framework powered by high-throughput computations and machine learning for the des...
2109.10798v1
2021-10-04
Molten pool characteristics of a nickel-titanium shape memory alloy for directed energy deposition
Fabrication of nickel-titanium shape memory alloy through additive manufacturing has attracted increasing interest due to its advantages of flexible manufacturing capability, low-cost customization, and minimal defects. The process parameters in directed energy deposition (DED) have a crucial impact on its molten pool ...
2110.01145v1
2021-10-08
Design and Characterization of Self Lubricating Refractory High Entropy Alloy Based Multilayered Films
Refractory high entropy alloys (RHEA) have been proven to have excellent mechanical properties with a potential use as protective thin films. However, the combination of high hardness with low friction and wear is a major challenge in the design of self lubricating RHEA films. In this study, we show that designing of N...
2110.04199v2
2021-10-14
Ab-initio study of ultrafast spin dynamics in Gdx(FeCo){1-x} alloys
Using an ultrashort laser pulse we explore {\it ab-initio} the spin dynamics of Gd$_x$(FeCo)$_{1-x}$ at femtosecond time scales. Optical excitations are found to drive charge from Fe majority $d$-states to the unoccupied Gd $f$-minority states, with $f$-electron character excited occupation lagging behind that of the $...
2110.07180v1
2021-10-20
Manifestations of Spinodal Decomposition into Dilute Pd$_{1-x}$Fe$_{x}$ "Phases" in Iron-Implanted Palladium Films: FMR Study
Palladium-iron alloys produced by high-dose implantation of iron ions into epitaxial palladium films were investigated with the ferromagnetic resonance (FMR) and vibrating sample magnetometry (VSM) techniques. The samples reveal distinct multiple FMR responses depending on the dose of iron ion implantation. The post-im...
2110.10397v1
2021-10-23
Shear banding instability in \remove{high entropy} multi-component metallic glasses: Interplay of composition and short-range order}
The shear-banding instability in quasi-statically driven bulk metallic glasses emerges from collective dynamics, mediated by shear transformation zones and associated non-local elastic interactions. It is also phenomenologically known that sharp structural features of shear bands are typically correlated to the sharpne...
2110.12152v1
2021-10-31
\textit{Ab initio} Studies of Magnetism and Topology in solid Pd-rich a-PdSi Alloys
In 1965 Duwez \textit{et al.} reported having generated an amorphous, stable phase of palladium-silicon in the region 15 to 23 atomic percent (at. \%) silicon. These pioneering efforts have led to the development of solid materials that are now known as Bulk Metallic Glasses (BMG). In 2019 we discovered, computationall...
2111.00394v1
2021-11-01
Predicting properties of hard-coating alloys using ab-initio and machine learning methods
Accelerated design of novel hard coating materials requires state-of-the-art computational tools, which include data-driven techniques, building databases, and training machine learning models against the databases. In this work, we present a development of a heavily automated high-throughput workflow to build a databa...
2111.01111v2
2021-11-15
In situ Bragg coherent X-ray diffraction imaging of corrosion in a Co-Fe alloy microcrystal
Corrosion is a major concern for many industries, as corrosive environments can induce structural and morphological changes that lead to material dissolution and accelerate material failure. The progression of corrosion depends on nanoscale morphology, stress, and defects present. Experimentally monitoring this complex...
2111.07903v5
2021-12-13
Robustness of superconductivity to external pressure in high-entropy-alloy-type metal telluride AgInSnPbBiTe5
High-entropy-alloy (HEA) superconductors are a new class of disordered superconductors. In this study, we investigate the robustness of superconducting states in HEA-type metal telluride (MTe; M = Ag, In, Sn, Pb, Bi) under high pressure. PbTe exhibits a structural transition from a NaCl-type to an orthorhombic Pnma str...
2112.06461v1
2022-01-07
First-principles study on the solute-induced low diffusion and self-trapping of helium in fcc iron
The addition of alloying elements plays an essential role in helium (He) behaviours produced by transmutation in metal alloys. Effects of solutes (Ni, Cr, Ti, P, Si, C) on the behaviours of He and He-He pair in face-centred cube (fcc) iron have been investigated using first-principles calculations based on density func...
2201.02423v1
2022-01-20
Density functional study of twisted graphene $L1_0$-FePd heterogeneous interface
Graphene on $L1_0$-FePd(001), which has been experimentally studied in recent years, is a heterogeneous interface with a significant lattice symmetry mismatch between the honeycomb structure of graphene and tetragonal alloy surface. In this work, we report on the density functional study of its atomic-scale configurati...
2201.07942v4
2022-01-20
Stabilization of CeGe$_3$ with Ti and O featuring tetravalent Ce ions: (Ce$_{0.85}$Ti$_{0.15}$)Ge$_3$O$_{0.5}$
Sub-oxides with the anti-perovskite structure constitute a large part of the interstitial stabilized compounds with novel chemical and physical properties, especially in the systems containing rare earth elements and/or early transition metal elements. A new sub-oxide compound, (Ce$_{0.85}$Ti$_{0.15}$)Ge$_3$O$_{0.5}$, ...
2201.08449v1
2022-01-28
The effect of B-site alloying on the electronic and opto-electronic properties of RbPbI3: A DFT study
Divalent cations mixed lead halide perovskites with enhanced performances, high stabilities, and reduced toxicity are requisite to make persistent progress in perovskite solar cells. However, the mixing strategy is not reported extensively in search of a lead reduced structure. Herein, we report the structural, electro...
2201.11966v1
2022-04-07
Identification of radiopure tungsten for low background applications
In this article we explore the availability of radiopure tungsten and its potential as high density shield material for low background applications. For compact shield designs, conventionally, lead is used. Metallic tungsten and tungsten pseudo-alloys reach higher densities up to 19.3 gcm$^{-3}$ and do not exhibit a si...
2204.03540v1
2022-04-08
Numerical simulation of the EM forced flow during Sn-Pb alloy directional horizontal solidification
This article presents a study of the influence of electromagnetically (EM) forced convection on segregation formation. As a reference case the solidification of Sn-5 wt pct Pb alloy from the Hebditch and Hunt experiment is taken. Applied forcing of convective flow is determined by the dimensionless electromagnetic forc...
2204.03650v1
2022-04-13
Computational Design of Alloy Nanostructures for Optical Sensing of Hydrogen
Pd nanoalloys show great potential as hysteresis-free, reliable hydrogen sensors. Here, a multi-scale modeling approach is employed to determine optimal conditions for optical hydrogen sensing using the Pd-Au-H system. Changes in hydrogen pressure translate to changes in hydrogen content and eventually the optical spec...
2204.06229v2
2022-04-30
Development of an electron impact ion source with high ionization efficiency for future planetary missions
Ion sources using electron impact ionization (EI) methods have been widely accepted in mass spectrometry for planetary exploration missions because of their simplicity. Previous space-borne mass spectrometers were primarily designed with the EI method using rhenium tungsten alloy filaments, enabling up to 200 uA emissi...
2205.00246v2
2022-04-26
Metastable defects decrease the fill factor of solar cells
Cu(In,Ga)Se2 based solar cells exceed power conversion efficiencies of 23 %. Yet, the fill factor of these solar cells, with best values around 80 %, is relatively low (Si reaches 84.9%) mostly due to diode factors greater than one. Recently, we proposed metastable defects, a general feature of the Cu(In,Ga)Se2 alloy, ...
2205.00826v1
2022-05-06
Mechanisms of strength and hardening in austenitic stainless 310S steel: Nanoindentation experiments and multiscale modeling
Austenitic stainless steels with low carbon have exceptional mechanical properties and are capable to reduce embrittlement, due to high chromium and nickel alloying, thus they are very attractive for efficient energy production in extreme environments. It is key to perform nanomechanical investigations of the role of c...
2205.03050v1
2022-06-08
Predictions of Electromotive Force of Magnetic Shape Memory Alloy (MSMA) Using Constitutive Model and Generalized Regression Neural Network
Ferromagnetic shape memory alloys (MSMAs), such as Ni-Mn-Ga single crystals, can exhibit the shape memory effect due to an applied magnetic field at room temperature. Under a variable magnetic field and a constant bias stress loading, MSMAs have been used for actuation applications. This work introduced a new feature t...
2206.03701v3
2022-06-10
Elemental (im-)miscibility determines phase formation of multinary nanoparticles co-sputtered in ionic liquids
Non-equilibrium synthesis methods allow to alloy bulk-immiscible elements into multinary nanoparticles, which broadens the design space for new materials. Whereas sputtering onto solid substrates can combine immiscible elements into thin film solid solutions, this is not clear for sputtering of nanoparticles in ionic l...
2206.04963v1
2022-06-20
Integrating Machine Learning with Mechanistic Models for Predicting the Yield Strength of High Entropy Alloys
Accelerating the design of materials with targeted properties is one of the key materials informatics tasks. The most common approach takes a data-driven motivation, where the underlying knowledge is incorporated in the form of domain-inspired input features. Machine learning (ML) models are then built to establish the...
2206.09944v1