A first-principles phase field method for quantitatively predicting multi-composition phase separation without thermodynamic empirical parameter

Bhattacharyya, Swastibrata; Sahara, Ryoji; Ohno, Kaoru

doi:10.1038/s41467-019-11248-z

Cited by 21 publications

(19 citation statements)

References 35 publications

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“…Futhermore, it is necessary to predict an accurate phase diagram of HEA to realize QSPR by combining the calculation of the phase diagram (CALPHAD) [48] and the firstprinciples based thermodynamic assessment [49]. We believe that the systematic investigation described herein will be helpful for realizing such an assessment and for predicting the microstructures of HEA by performing model simulations such as "first-principles phase field model" without any thermodynamic empirical parameters [50].…”

Section: Summary and Future Prospectsmentioning

confidence: 99%

Order-Disorder Competitive Cooperation in Equiatomic 3d-Transition-Metal Quaternary Alloys: Phase Stability and Electronic Structure

Mizuseki¹,

Sahara²,

Hongo³

2021

Preprint

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We use high-throughput first-principles sampling to investigate competitive factors that determine the crystal structure of high-entropy alloys (HEAs) and the energetics dependence of the stable phase on the atomic configuration of fully ordered L1 2 , D0 22 , and random solid solution (RSS) phases of equiatomic quaternary alloys comprising four of the six constituent elements (Cr, Mn, Fe, Co, Ni, and Cu). Considering the configurational entropy, we demonstrate that valence electron concentration (VEC) and temperature are crucial to determine the phase stability of HEAs at finite temperatures, wherein the ordered phases are energetically more favorable than RSS phases, and some D0 22 phases with high VEC are energetically more stable than L1 2 phases. Further, we explore magnetic configurations to identify the origin of the enthalpy term. The calculations reveal that ordered phases comprising antiferromagnetic atoms surrounded by ferromagnetic atoms are energetically stable. The quantitative structure-property relationship is also discussed.

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Section: Summary and Future Prospectsmentioning

confidence: 99%

Order-Disorder Competitive Cooperation in Equiatomic 3d-Transition-Metal Quaternary Alloys: Phase Stability and Electronic Structure

Mizuseki¹,

Sahara²,

Hongo³

2021

Preprint

Self Cite

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“…In principle, the atomic arrangement at the A–B interface is determined by its thermodynamic state, which is related to the combination of composition, structure, and environmental conditions. [ 108–110 ] A stable atomic arrangement must possess a lowered Gibbs free energy ( G ), which can be calculated by

\begin{matrix} G = H - T S \end{matrix}

where H , S , and T represent the enthalpy, entropy, and temperature, respectively. Therefore, the difference in G (Δ G A + B → AB ) between the single phases and interfacial composite is determined by

\begin{matrix} Δ G_{A + B \to AB} = Δ H_{A + B \to AB} - T Δ S_{A + B \to AB} \end{matrix}

…”

Section: Pathways To Manipulation Of Interfaces Down To Atomic Scalesmentioning

confidence: 99%

Manipulating Interfaces of Electrocatalysts Down to Atomic Scales: Fundamentals, Strategies, and Electrocatalytic Applications

Kou

Wang

2020

Small Methods

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Raising electrocatalysis by rationally devising catalysts plays a core role in almost all renewable energy conversion and storage systems. The principal catalytic properties can be controlled and improved well by manipulation of interfaces, ascribed to the interactions among different components/players at the interfaces. In particular, manipulating interfaces down to atomic scales is becoming increasingly attractive, not only because those atoms at around the interface are the key players during electrocatalysis, but also, understandings on the atomic level electrocatalysis allow one to gain deep insights into the reaction mechanism. With the feature down‐sizing to atomic scales, there is a timely need to redefine the interfaces, as some of them have gone beyond the conventionally perceived interfacial concept. In this overview, the key active players participating in the interfacial manipulation of electrocatalysts are examined, from a new angle of “atomic interface,” including those individual atoms, defects, and their interactions, together with the essential characterization techniques for them. The specific approaches and pathways to engineer better atomic interfaces are investigated, and thus to enable the unique electrocatalysis for targeted applications. Looking beyond recent progress, the challenges and prospects of the atomic level interfacial engineering are also briefly visited.

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“…The rate of phase transition may be determined using Allen-Cahn [7] equation for nonconserved order parameters, and Cahn-Hilliard [8] equation for conserved order parameters. Depending on the scale and the physical input data, Phase Field Modeling may be considered to be either a numerical tool or a first principles' approach [9,10]. PFMs have been used in a broad range of problems, ranging from microstructure evolution and solidification [11] to multiphase flows [12].…”

Section: Introductionmentioning

confidence: 99%

Microstructure Evolution in a Solid Oxide Fuel Cell Stack Quantified with Interfacial Free Energy

2021

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Degradation of electrode microstructure is one of the key factors affecting long term performance of Solid Oxide Fuel Cell systems. Evolution of a multiphase system can be described quantitatively by the change in its interfacial energy. In this paper, we discuss free energy of a microstructure to showcase the anisotropy of its evolution during a long-term performance experiment involving an SOFC stack. Ginzburg Landau type functional is used to compute the free energy, using diffuse phase distributions based on Focused Ion Beam Scanning Electron Microscopy images of samples taken from nine different sites within the stack. It is shown that the rate of microstructure evolution differs depending on the position within the stack, similar to phase anisotropy. However, the computed spatial relation does not correlate with the observed distribution of temperature.

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A first-principles phase field method for quantitatively predicting multi-composition phase separation without thermodynamic empirical parameter

Cited by 21 publications

References 35 publications

Order-Disorder Competitive Cooperation in Equiatomic 3d-Transition-Metal Quaternary Alloys: Phase Stability and Electronic Structure

Order-Disorder Competitive Cooperation in Equiatomic 3d-Transition-Metal Quaternary Alloys: Phase Stability and Electronic Structure

Manipulating Interfaces of Electrocatalysts Down to Atomic Scales: Fundamentals, Strategies, and Electrocatalytic Applications

Microstructure Evolution in a Solid Oxide Fuel Cell Stack Quantified with Interfacial Free Energy

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