Establishment of innovative calculation method for physical properties in multicomponent alloys from spacial constraint

2019 Fiscal Year Final Research Report

• Project/Area Number: 16K06704
• Research Category: Grant-in-Aid for Scientific Research (C)
• Allocation Type: Multi-year Fund
• Section: 一般
• Research Field: Physical properties of metals/Metal-base materials
• Research Institution: Kyoto University
• Principal Investigator: YUGE Koretaka 京都大学, 工学研究科, 准教授 (70512862)
• Project Period (FY): 2016-04-01 – 2020-03-31
• Keywords: 空間的拘束 / 配位空間の幾何学 / 非線型離散系

Outline of Final Research Achievements

The present research focuses on spacial constraint on constituent particles of given systems, developing new theoretical approach enabling to describe physical properties for crystalline solids in thermodynamic equilibrium: We establish new calculation methodology with much higher efficiency that existing methods for predicting temperature-dependence of physical properties in multicomponent alloys.
Consequently, we elucidate a set of a few specially-selected microscopic states independent of energy and of temperature, which can characterize temperature dependence of microscopic states and/or free energy for thermodynamically equilibrium states. By applying these states to first-principles calculations, we find (i) that Short-range ordering for ternary, quaternary and quinary systems can be systematically characterized only by geometric information about constituent elements, and (ii) condition for performing stable inverse-prediction from measured structure to many-body interactions.

Free Research Field

統計力学

Academic Significance and Societal Importance of the Research Achievements

本研究の最大の学術的意義は、従来の古典統計力学では平衡状態の巨視的な性質に主要な寄与をする微視的状態は温度・相互作用に依存するために先験的に知ることはできない、という考えに対して空間的拘束の役割を定量的に解明することでパラダイムシフトを起こし、主要な微視的状態を拘束条件のみに依存した形で先験的に知ることができることを明らかにした点にある。その結果、従来手法で行っていた試行錯誤的なサンプリングを行うことなく、構成元素や多体相互作用が変化しても空間的拘束の条件に固有の特殊な微視的状態の集合のみについて物理量を計算することで、熱力学的平衡状態の性質を体系的・包括的に予測できる計算手法を確立した。