Material microstructure design based on prediction of grain boundary segregation of solute atoms

2023 Fiscal Year Final Research Report

• Project/Area Number: 21K04687
• Research Category: Grant-in-Aid for Scientific Research (C)
• Allocation Type: Multi-year Fund
• Section: 一般
• Review Section: Basic Section 26040:Structural materials and functional materials-related
• Research Institution: Nagoya University
• Principal Investigator: Tsukada Yuhki 名古屋大学, 工学研究科, 准教授 (00620733)
• Project Period (FY): 2021-04-01 – 2024-03-31
• Keywords: 粒界偏析 / 多成分系合金 / ニッケル基超合金 / オーステナイト系ステンレス鋼 / ハイエントロピー合金 / マグネシウム合金 / ソリュートドラッグ / フェーズフィールド法

Outline of Final Research Achievements

A computational code was developed to predict the grain boundary composition of multi-component alloys using a thermodynamic database of calculation of phase diagrams. For several multi-component alloys, the predicted grain boundary compositions were shown to agree with literature data (experimental values). It was also shown that when the grain size is 10 μm or less, it is necessary to consider the effect of the grain boundary volume fraction in the computation of grain boundary composition. The grain boundary compositions of 32 types of nickel-base superalloys were predicted, and the results were used as explanatory variables to construct a creep strength prediction model. As a result, it was revealed that grain boundary segregation of boron is effective in increasing the creep strength of nickel-base superalloys.

Free Research Field

計算材料組織学

Academic Significance and Societal Importance of the Research Achievements

計算状態図の熱力学データベースを用いて多成分・多相系の粒界組成の温度依存性を計算できることが示された意義は大きく、今後、種々の合金開発での活用が期待される。また、粒界組成の予測結果をクリープ強度予測モデルの説明変数に用いることで、ニッケル基超合金のクリープ強度の発現における粒界偏析の重要度の理解につながった。このアプローチは耐熱鋼をはじめとする他の耐熱材料にも適用可能であり、粒界偏析を考慮したクリープ強度予測、ならびに材料組織設計の実現に寄与すると考えられる。