We use current-perpendicular-to-plane (CPP) exchange-biased spin-valves to directly measure spin diffusion lengths lsf for N = Cu(2.1 at.%Ge) and Ag(3.6 at.%Sn) alloys. We find lsf(Cu2%Ge)) = 117+10-6 nm and lsf(Ag4%Sn)= 39 +/- 3 nm. The good agreement of this lsf(Cu2%Ge) with the value lsf(Cu2%Ge) = 121 +/- 10 nm derived from an independent spin-orbit cross-section measurement for Ge in Cu, quantitatively validates the use of Valet-Fert theory for CPP-MR data analysis to layer thicknesses several times larger than had been done before.
From the value of lsf(Ag4%Sn), we predict the ESR spin-orbit cross-section for Sn impurities in Ag.
An extensive set of first-principles density functional theory calculations have been performed to study the behaviour of He, C and N solutes in austenite, dilute Fe-Cr-Ni austenitic alloys and Ni in order to investigate their influence on the microstructural evolution of austenitic steel alloys under irradiation.
We present results of an extensive set of first-principles density functional theory calculations of point defect formation, binding and clustering energies in austenitic Fe with dilute concentrations of Cr and Ni solutes.
Mn doping in dilute III-V alloys has been examined as a route to enhance ferromagnetic stability. Strong valence band bowing is expected at the dilute limit, implying a strong modification of the ferromagnetic stability upon alloying, with even an increase in some cases. Using first principle electronic structure calculations we show that while codoping with a group V anion enhances the ferromagnetic stability in some cases when the effects of relaxation of the lattice are not considered, strong impurity scattering in the relaxed structure result in a reduction of the ferromagnetic stability.
For powder samples of CuAl$_{1-x}$Fe$_x$O$_2$ ($x =$ 0, 0.01, 0.05, and 0.1), measured optical properties are compared with model simulations and phonon spectra are compared with simulations based on weighted dynamical matrix approach.
The present work examines the effect of alloying elements (denoted X) on the ideal shear strength for 26 dilute Ni-based alloys, Ni$_{11}$X, as determined by first-principles calculations of pure alias shear deformations. The variations in ideal shear strength are quantitatively explored with correlational analysis techniques, showing the importance of atomic properties such as size and electronegativity. The shear moduli of the alloys are affirmed to show a strong linear relationship with their ideal shear strengths, while the shear moduli of the individual alloying elements were not indicati…
The addition of dilute concentrations of bismuth (Bi) into GaAs to form GaBiAs alloys results in a large reduction of the band gap energy Eg accompanied by a significant increase of the spin-orbit-splitting energy (delta_SO), leading to an Eg < delta_SO regime for ~10% Bi composition which is technologically relevant for the design of highly efficient photonic devices. The quaternary alloy GaBiNAs offers further flexibility for band gap tuning, because both nitrogen and bismuth can independently induce band gap reduction. This work reports sp3s* tight binding and 14-band k.p models for the stu…
A multiple scattering formulation for the electromigration wind force on atoms in dilute alloys is developed. The theory describes electromigration via a vacancy mechanism. The method is used to calculate the wind valence for electromigration in various host metals having a close-packed lattice structure, namely aluminum, the noble metals copper, silver and gold and the $4d$ transition metals. The self-electromigration results for aluminum and the noble metals compare well with experimental data. For the $4d$ metals small wind valences are found, which make these metals attractive candidates f…
The vacancy concentration at finite temperatures is studied for a series of (CoCrFeMn)$_{1-x_\mathrm{Ni}}$Ni$_{x_\mathrm{Ni}}$ alloys by grand-canonical Monte-Carlo (MC) simulations. The vacancy formation energies are calculated from a classical interatomic potential and exhibit a distribution due to the different chemical environments of the vacated sites. In dilute alloys, this distribution features multiple discrete peaks, while concentrated alloys exhibit an unimodal distribution as there are many different chemical environments of similar vacancy formation energy. MC simulations using a n…
The challenging problem of skew scattering for Hall effects in dilute ferromagnetic alloys, with intertwined effects of spin-orbit coupling, magnetism and impurity scattering, is studied here from first principles. Our main aim is to identify chemical trends and work out simple rules for large skew scattering in terms of the impurity and host states at the Fermi surface, with particular emphasis on the interplay of the spin and anomalous Hall effects in one and the same system. The predicted trends are benchmarked by referring to three different \emph{ab initio} methods based on different appr…
The occurrence of segregation in highly dilute alloys under irradiation is an unusual phenomenon that has so far eluded theoretical explanation. Using ab initio calculations, we are able to explain the origin of radiation-induced rhenium segregation in dilute tungsten-rhenium alloys.
Incorporation of bismuth (Bi) in dilute quantities in (In)GaAs has been shown to lead to unique electronic properties that can in principle be exploited for the design of high efficiency telecomm lasers. This motivates the development of simple models of the electronic structure of these dilute bismide alloys, which can be used to evaluate their potential as a candidate material system for optical applications. Here, we begin by using detailed calculations based on an $sp^{3}s^{*}$ tight-binding model of (In)GaBi$_{x}$As$_{1-x}$ to verify the presence of a valence band-anticrossing interaction…
A series of structural polytypes formed in an Mg-1at.%Zn-2at.%Y alloy has been identified, which are reasonably viewed as long-period stacking derivatives of the hcp Mg structure with alternate AB stacking of the close-packed atomic layers. Atomic-resolution Z-contrast imaging clearly revealed that the structures are long-period chemical-ordered as well as stacking-ordered; unique chemical order along the stacking direction occurs as being synchronized with a local faulted stacking of AB'C'A, where B' and C' layers are commonly enriched by Zn/Y atoms.
We present a theoretical analysis of electronic structure evolution in the highly-mismatched dilute carbide group-IV alloy Ge$_{1-x}$C$_{x}$. For ordered alloy supercells, we demonstrate that C incorporation strongly perturbs the conduction band (CB) structure by driving hybridisation of $A_{1}$-symmetric linear combinations of Ge states lying close in energy to the CB edge. This leads, in the ultra-dilute limit, to the alloy CB edge being formed primarily of an $A_{1}$-symmetric linear combination of the L-point CB edge states of the Ge host matrix semiconductor. Our calculations describe the…
We present the first resonant x-ray reflectivity measurements from a liquid surface. The surface structure of the liquid Hg-Au alloy system just beyond the solubility limit of 0.14at% Au in Hg had previously been shown to exhibit a unique surface phase characterized by a low-density surface region with a complicated temperature dependence. In this paper we present reflectivity measurements near the Au LIII edge, for 0.2at% Au in Hg at room temperature. The data are consistent with a concentration of Au in the surface region that can be no larger than about 30at%. These results rule out previou…
Impurity diffusion in Zr is potentially important for many applications of Zr alloys, and in particular for their use of nuclear reactor cladding. However, significant uncertainty presently exists about which elements are vacancy vs. interstitial diffusers, which can inhibit understanding and prediction of their behavior under different temperature, irradiation, and alloying conditions. Therefore, first-principles calculations based on density functional theory (DFT) have been employed to predict the temperature-dependent dilute impurity diffusion coefficients for 14 substitutional alloying el…
Impurity diffusion coefficients are entirely obtained from a low cost classical molecular statics technique (CMST). In particular, we show how the CMST is appropriate in order to describe the impurity diffusion behavior mediated by a vacancy mechanism. In the context of the five-frequency model, CMST allows to calculate all the microscopic parameters, namely: the free energy of vacancy formation, the vacancy-solute binding energy and the involved jump frequencies, from them, we obtain the macroscopic transport magnitudes such as: correlation factor, solvent-enhancement factor, Onsager and diff…
We present the results of ab initio modeling of structure of dilute Ti-Fe, a typical representative of quenched Ti-based transition-metal alloys. We have demonstrated that beyond the solubility limit this alloy cannot be described in common terms of substitutional and interstitial alloys. Instead, very stable local clusters are formed in both low-temperature hcp and high-temperature bcc phases of alloys, with almost identical local structures. This gives an example of geometrically frustrated state and explains unusual concentration behavior of Mössbauer spectra discovered long ago for this sy…
Planar solidification from an undercooled melt has been considered using the phase-field model. The solute and the phase fields have been found in the limit of small impurity concentration. These solutions in the limit of vanishing velocity of the interface motion give the equilibrium partition coefficient and the liquidus slope. Asymptotic expansions for the solute and for the phase fields, and the relation between the diffusive speed and the parameters of the phase field model have been found at high growth velocity. A comparison with numerical calculations is presented.
The thermodynamic activities of all components in Ga-In-Tl system have been predicted at 1073, 1173 and 1273 K, using Molecular interaction volume model (MIVM). The infinite dilute activity coefficients for Ga-In and Ga-Tl binary subsystems, which were needed for the determination of thermodynamic activities of all components in Ga-In-Tl, have been predicted by using a method that is based on Complex formation model for liquid alloys. The computed thermodynamic activities of Ga in Ga-In-Tl were observed to satisfactorily agree with the available experimental data when the newly computed coeffi…
Impurity diffusion coefficients are entirely obtained from a low cost classical molecular statics technique (CMST). In particular, we show how CMST is appropriate in order to describe the impurity diffusion behavior mediated by a vacancy mechanism. In the context of the five-frequency model, CMST allows to calculate all the microscopic parameters, namely: the free energy of vacancy formation, the vacancy-solute binding energy and the involved jump frequencies, from them, we obtain the macroscopic transport magnitudes such as: correlation factor, solvent-enhancement factor, Onsager and diffusio…
In the present work, a thin film was deposited on quartz substrate by reactive RF magnetron sputtering of high purity (99.999%) aluminium target using ultra-high pure (Ar + N2) gas mixture. The percentage ratio of Ar and N2 in the gas mixture was 95% and 5%, respectively. Chemical characterization using x-ray photoelectron spectroscopy (XPS) and energy-dispersive xray (EDX) spectroscopy reveals that in the presence of dilute nitrogen, Al prefers to react with residual oxygen to form Al2O3 while the nitrogen is incorporated in it. The stoichiometry of bulk film is Al2N0.38O3.1. Magnetic and ele…
Using an ab initio approach, we explore the stability of small vacancy and vacancy-chromium clusters in dilute body-centred cubic Fe-Cr alloys. To explain experimental observations described in C.D. Hardie et al., J. Nucl. Mater. 439, 33 (2013) and showing the occurrence of Cr segregation in low-Cr alloys, we investigate if chromium can form stable bound configurations with vacancies in alloys with chromium concentration below the low-temperature chromium solubility limit of 10-11 at. %. We find that a single vacancy can attract up to four Cr atoms in the most energetically favourable cluster …
The technological concept of "digital alloying" offered by molecular-beam epitaxy is demonstrated to be a very effective tool for tailoring static and dynamic magnetic properties of diluted magnetic semiconductors. Compared to common "disordered alloys" with the same Mn concentration, the spin-lattice relaxation dynamics of magnetic Mn ions has been accelerated by an order of magnitude in (Cd,Mn)Te digital alloys, without any noticeable change in the giant Zeeman spin splitting of excitonic states, i.e. without effect on the static magnetization. The strong sensitivity of the magnetization dyn…
The mobility of vacancies in alloys may limit dislocation climb. Using a combined density functional theory and kinetic Monte Carlo approach we investigate vacancy diffusion in Ni-Re, Ni-W, and Ni-Ta binary alloys up to 10 at.% solute concentration. We introduce an interaction model that takes into account the chemical environment close to the diffusing atom to capture the effect of solute-host and solute-solute interactions on the diffusion barriers. In contrast to an ideal solid solution it is not only the diffusion barrier of the solute atom that influences the vacancy mobility, but primari…
Using an asymptotic solution of the M-impurity thermodynamics of a dilute s-d system, the impurity energy and impurity heat capacity DeltaC(T) are derived for dilute magnetic alloys with spin 1/2 and spin 3/2 impurities. The parameters which enter DeltaC are adjusted to fit experimental data on impurity heat capacity of CuCr and LaCeAl_2. Agreement is satisfactory for CuCr, at temperatures below 1K, and good for LaCeAl_2. The magnitude of theoretical DeltaC(T) agrees with experiment and does not require scaling as in previous s-d theories. Nonlinear dependence of DeltaC(T) on impurity concentr…
Investigation of ideal shear strength of dilute binary and ternary Ni-based alloys using first-principles calculations, CALPHAD modeling and correlation analysis
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-close-packed (hcp) Mg matrix forms a local face-centered-cubic (fcc) environment, and hence our thermodynamic analysis is based on the Gibbs energy comparison between hcp and fcc phases over the Mg-Zn-Y ternary composition ranges, using the calculation of phase diagrams (CALPHAD) me…
The variation of TO zone-center vibration spectra with concentration in mixed zincblende-type semiconductors can be understood within a paradigm of unified "one bond - two modes" approach, which has been recently outlined as a rather general concept, and emerges from a number of previous experimental and theoretical studies. The crucial issue is that the vibration frequency, associated with a certain cation-anion bond, depends on the length of the latter, and the bond length, in its turn, depends not only on the average alloy concentration, but on local variations of it. In an (A,B)C substitut…
Dilute bismuth (Bi) III-V alloys have recently attracted great attention, due to their properties of band-gap reduction and spin-orbit splitting. The incorporation of Bi into antimonide based III-V semiconductors is very attractive for the development of new optoelectronic devices working in the mid-infrared range (2-5 $μ$m). However, due to its large size, Bi does not readily incorporate into III-V alloys and the epitaxy of III-V dilute bismides is thus very challenging. This book chapter presents the most recent developments in the epitaxy and characterization of GaSbBi alloys and heterostru…
Starting from a phase-field description of the isothermal solidification of a dilute binary alloy, we establish a model where capillary waves of the solidification front interact with the diffusive concentration field of the solute. The model does not rely on the sharp-interface assumption, and includes non-equilibrium effects, relevant in the rapid-growth regime. In many applications it can be evaluated analytically, culminating in the appearance of an instability which, interfering with the Mullins-Sekerka instability, is similar to that, found by Cahn in grain-boundary motion.
An argument is given showing that Coulomb attraction between conduction electrons and impurity ions in a dilute magnetic alloy (DMA) can be disregarded, provided the system's inverse temperature beta is replaced by an effective inverse temperature t < beta. This replacement allows to remove the singularity in Kondo's expression for DMA impurity resistivity and extend his theory to 0 K. The extended Kondo formula agrees with experimental data on resistivity of CuFe in the range of low temperatures and in the neighbourhood of the resistivity minimum. Using an asymptotic solution of the thermodyn…
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 forced atomic relocations (FAR) occurring in displacement cascades. We derive an analytic model of the PD and solute RIS profiles accounting for PD production and mutual recombination, the FAR mechanism, and the overall sink strength of the microstructure controlling the elimination o…
An archetypical spin-glass metallic alloy, Cu0.83Mn0.17, is studied by means of an ab-initio based approach. First-principles calculations are employed to obtain effective chemical, strain-induced and magnetic exchange interactions, as well as static atomic displacements, and the interactions are subsequently used in thermodynamic simulations. It is shown that the calculated atomic and magnetic short-range order accurately reproduces the results of neutron-scattering experiments. In particular, it is confirmed that the alloy exhibits a tendency toward ordering and the corresponding ordered pha…
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 ($E_{g}^Γ$) and valence band spin-orbit splitting energy ($Δ_{\textrm{SO}}$). $E_{g}^Γ$ ($Δ_{\textrm{SO}}$) is measured to decrease (increase) by approximately 200 meV (240 meV) with the incorporation of 1% Bi, corresponding to a greater than fourfold increase in $Δ_{\textrm{SO}}$ in going from GaP to GaP$_{0.99}$Bi$_{0.01}$. The evolution of $E_{g}^Γ$ and $Δ_{\textrm{SO}}$ with $x$ is characterised by strong, composition-dependent bowing. …
Anion substitution with bismuth (Bi) in III-V semiconductors is an effective method for experimental engineering of the band gap Eg at low Bi concentrations, in particular in gallium arsenide (GaAs). The inverse Bi-concentration dependence of Eg has been found to be linear at low concentrations x and dominated by a valence band-defect level anticrossing between As and Bi occupied p levels. This dependence breaks down at high concentrations where empirical models accounting only for the As-Bi interaction are not applicable. Predictive models for the valence band hybridization require a first-pr…
Dilute-N GaPAsN alloys have great potential for optoelectronics lattice-matched to Si. However, there is a lack of systematic calculation of the optical response of these alloys. The present paper uses the sp^3d^5s^*s_N tight-binding model to calculate the fullband electronic structure of dilute-N GaPAsN, and then calculate the optical response functions considering direct transitions within the electric dipole approximation. Good agreement is obtained for the dielectric function in comparison to available optical data for dilute nitrides. To achieve this, the sp^3d^5s^* parameters for GaP and…
We demonstrate automated generation of diffusion databases from high-throughput density functional theory (DFT) calculations. A total of more than 230 dilute solute diffusion systems in Mg, Al, Cu, Ni, Pd, and Pt host lattices have been determined using multi-frequency diffusion models. We apply a correction method for solute diffusion in alloys using experimental and simulated values of host self-diffusivity. We find good agreement with experimental solute diffusion data, obtaining a weighted activation barrier RMS error of 0.176 eV when excluding magnetic solutes in non-magnetic alloys. The …
Kinetics of homogeneous nucleation and growth of copper precipitates under electron irradiation of Fe_{1-x}Cu_x alloys at concentrations x from 0.06 at.% to 0.4 at.% and temperatures T from 290 to 450C is studied using the kinetic Monte Carlo (KMC) simulations and the statistical theory of nucleation (STN). The conventional assumption about the similarity of mechanisms of precipitation under electron irradiation and during thermal aging is adopted. The earlier-developed ab initio model of interactions in Fe-Cu alloys is used for both the KMC simulations and the STN calculations. Values of the …
Deconvoluting Mechanisms of Radiation-Induced Grain Boundary Segregation in Dilute Ni-X (X = Fe, Cr, Mn) Alloys via Ion Irradiation and Phase-field Modeling
Idaho National Laboratory（爱达荷国家实验室）；Texas A&M University（德克萨斯农工大学）
Tracer diffusion of the substitutional components in (CoCrFeNiMn)$_{1-x}$C$_x$ high-entropy alloys with x = 0.002, 0.005 and 0.008 (in at. fractions) is measured at elevated temperatures from 1173 to 1373 K. Two different characteristic effects of interstitial carbon addition on substitutional diffusion in these FCC alloys are distinguished. At the highest temperature of 1373 K, alloying by C with relatively low concentrations (x = 0.002) retards diffusion of the substitutional elements with respect to those in the C-free alloy. At lower temperatures and/or higher C concentrations (x > 0.005),…
In this article, we combine casting experiments and quantitative simulations to present a novel multiscale modeling approach to predict local primary dendritic spacings in metallic alloys solidified in conditions relevant to industrial casting processes. To this end, primary dendritic spacings were measured in instrumented casting experiments in Al-Cu alloys containing 1\,wt\% and 4\,wt\% of Cu, and they were compared to spacing stability ranges and average spacings in dendritic arrays simulated using phase-field (PF) and dendritic needle network (DNN) models. It is first shown that PF and DNN…
The liquid-solid diffusion couple technique, supported by phenomenological analysis and nano-indentation tests, is proposed on account of the relatively low melting points of Mg to explore the diffusion mobility and creep deformation. The potential of this strategy is demonstrated in Mg-Ga hcp alloys where Ga solute (i.e. impurity) and Mg solvent diffusions in hcp Mg-Ga alloys were both unveiled. It was followed by mapping the compressive creep behavior via nanoindentation along the composition arrays within the same Mg-Ga couple sample. The compressive creep resistance of Mg-Ga hcp alloys inc…
We discuss hydrogen diffusion and solubility in aluminum alloyed Fe-Mn alloys. The systems of interest are subjected to tetragonal and isotropic deformations. Based on ab initio modelling, we calculate solution energies, then employ Oriani's theory which reflects the influence of Al alloying via trap site diffusion. This local equilibrium model is complemented by qualitative considerations of Einstein diffusion. Therefore, we apply the climbing image nudged elastic band method to compute the minimum energy paths and energy barriers for hydrogen diffusion. Both for diffusivity and solubility of…
Tracer diffusion of all constituting elements is studied at various temperatures in a series of (CoCrFeMn)$_{100-x}$Ni$_x$ alloys with compositions ranging from pure Ni to the equiatomic CoCrFeMnNi high-entropy alloy. At a given homologous temperature, the measured tracer diffusion coefficients change non-monotonically along the transition from pure Ni to the concentrated alloys and finally to the equiatomic CoCrFeMnNi alloy. This is explained by atomistic Monte-Carlo simulations based on a modified embedded-atom potentials, which reveal that local heterogeneities of the atomic configurations …
Mg grain boundary (GB) segregation and GB diffusion can impact the processing and properties of Al-Mg alloys. Yet, Mg GB diffusion in Al has not been measured experimentally or predicted by simulations. We apply atomistic computer simulations to predict the amount and the free energy of Mg GB segregation, and the impact of segregation on GB diffusion of both alloy components. At low temperatures, Mg atoms segregated to a tilt GB form clusters with highly anisotropic shapes. Mg diffuses in Al GBs slower than Al itself, and both components diffuse slowly in comparison with Al GB self-diffusion. …
We simulate dendritic growth in directional solidification in dilute binary alloys using a phase-field model solved with an adaptive-mesh refinement. The spacing of primary branches is examined for a range of thermal gradients and alloy compositions and is found to undergo a maximum as a function of pulling velocity, in agreement with experimental observations. We demonstrate that wavelength selection is unambiguously described by a non-trivial crossover scaling function from the emergence of cellular growth to the onset of dendritic fingers, a result validated using published experimental dat…
Many of the purported virtues of Multi-Principal Element Alloys (MPEAs), such as corrosion, high-temperature oxidation and irradiation resistance, are highly sensitive to vacancy diffusivity. Similarly, solute interdiffusion is governed by vacancy diffusion -- it is often unclear whether MPEAs are truly stable, or effectively stabilized by slow interdiffusion. The considerable composition space afforded to these alloys makes optimizing for desired properties a daunting task; theoretical and computational tools are necessary to guide alloy development. For diffusion, such tools depend on both a…
The spontaneous magnetization as a function of temperature is investigated for a number of disordered Ni-Fe-Mo and Ni-Fe-W alloys using superconducting quantum interference device magnetometry, with a focus on the low-T behavior as well as the critical exponents associated with the magnetic phase transition. While the low-T magnetization is found to be well described by Bloch's T^{3/2} law, an extraordinary enhancement of the spin-wave parameter B and the reduced coefficient B_{3/2}=BT_C ^{3/2} are observed with increasing Fe dilution as compared to conventional 3d ferromagnets, whereas the cr…
While it is known that alloy components can segregate to grain boundaries (GBs), and that the atomic mobility in GBs greatly exceeds the atomic mobility in the lattice, little is known about the effect of GB segregation on GB diffusion. Atomistic computer simulations offer a means of gaining insights into the segregation-diffusion relationship by computing the GB diffusion coefficients of the alloy components as a function of their segregated amounts. In such simulations, thermodynamically equilibrium GB segregation is prepared by a semi-grand canonical Monte Carlo method, followed by calculat…
We develop an atomistic, nearest-neighbor sp3s* tight-binding Hamiltonian to investigate the electronic structure of dilute bismide alloys of GaP and GaAs. Using this model we calculate that the incorporation of dilute concentrations of Bi in GaP introduces Bi-related defect states in the band gap, which interact with the host matrix valence band edge via a Bi composition dependent band anti-crossing (BAC) interaction. By extending this analysis to GaBiAs we demonstrate that the observed strong variation of the band gap Eg and spin-orbit-splitting (SO) energy with Bi composition can be well ex…
Spark Plasma Sintering for high-speed diffusion welding of the ultrafine grained near-a Ti-5Al-2V alloy with high strength and corrosion resistance for nuclear engineering
We present a new modeling scheme for ion self-diffusion coefficient, which broadens the applicable scope of ab initio approach. The essential concepts of the scheme are `domain division' and `coarse graining' of the diffusion network based on the barrier energies predicted by the ab initio calculation. The scheme was applied to evaluate Cu ion self-diffusion coefficient in ε-Cu3Sn phase of Cu-Sn alloy, which is a typical system having long-range periodicity. The model constructed with the scheme successfully reproduces the experimental values in a wide temperature range.
Extracting Composition-Dependent Diffusion Coefficients Over a Very Large Composition Range in NiCoFeCrMn High Entropy Alloy Following Strategic Design of Diffusion Couples and Physics Informed Neural Network Numerical Method
Estimating the diffusion coefficients experimentally in a four-component inhomogeneous alloy following the conventional diffusion couple method by intersecting three couples at the same composition is difficult unless a small composition range of constant diffusivity is identified. Additionally, the intrinsic diffusion coefficients of the components cannot be estimated in a system with more than two components. To solve these issues, we have followed the pseudo-binary and pseudo-ternary diffusion couple methods for estimating the diffusion coefficients at the equiatomic composition of NiCoFeCr…
