高次Multi-phase-fieldモデリングによる粒成長過程の予測

Grain growth predictions by multi-phase-field modeling with higher-order term

廣内 智之*; 都留 智仁   ; 渋谷 陽二*

Hirouchi, Tomoyuki*; Tsuru, Tomohito; Shibutani, Yoji*

金属材料の内部組織を形成する過程の一つである粒成長過程では、粒界領域を減少させることが駆動力となるため、粒界エネルギーや粒界モビリティといった粒界特性が大きく影響する。本研究では、分子動力学法によって得られた純Alの対称傾角粒界の粒界エネルギー方位差依存性に基づき、粒界エネルギー分布をモデル化し、それを用いて三重点の自由エネルギーを考慮した高次項を持つ高次マルチフェイズフィールド(MPF)モデルを構築した。そして、粒界特性を考慮した多結晶体の粒成長過程の解析が可能であることを示した。

Multi-phase-field (MPF) modeling with a higher-order term, which can stably analyze the triple junction (TJ) behaviors even with large difference between grain boundary (GB) energies, is proposed for the more realistic grain growth prediction. Grain growth simulations of systems including multiple junctions show that the proposed MPF model can represent the stable TJ behaviors with wider range of GB energies than the conventional model, and well perform the quadruple junction behaviors in agreement with the responding theory. Two kinds of GB energy distribution models are employed here, which are based on all of and only low cuspate energies of 1 1 0 symmetric tilt GB energy in pure Al by molecular dynamics simulations. Polycrystalline grain growth simulations combining with either GB energy distribution exhibited the large amount of nucleation of low-energy boundaries, which would be quantitatively compatible to the experiments.