2019 Fiscal Year Final Research Report
Theoretical design of superalloys by a quantitative modelling based on first principles calculations
| Project/Area Number |
17K18998
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| Research Category |
Grant-in-Aid for Challenging Research (Exploratory)
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| Allocation Type | Multi-year Fund |
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| Research Field |
Materials engineering and related fields
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| Research Institution | National Institute for Materials Science |
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Principal Investigator |
SAHARA RYOJI 国立研究開発法人物質・材料研究機構, 構造材料研究拠点, 主幹研究員 (30323075)
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| Co-Investigator(Kenkyū-buntansha) |
大野 かおる 横浜国立大学, 大学院工学研究院, 教授 (40185343)
長田 俊郎 国立研究開発法人物質・材料研究機構, 構造材料研究拠点, 主幹研究員 (50596343)
戸田 佳明 国立研究開発法人物質・材料研究機構, 構造材料研究拠点, 主幹研究員 (60343878)
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| Project Period (FY) |
2017-06-30 – 2020-03-31
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| Keywords | 第一原理計算 / 耐熱合金 / 自由エネルギー計算 / 繰り込み |
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| Outline of Final Research Achievements |
In the present study, the thermodynamic properties of binary alloys for high temperature are evaluated. In order to obtain quantitatively accurate results, the results of first-principles calculations are mapped onto the fcc lattice using the renormalization technique, which can overcome some shortcomings of lattice-gas models such as neglecting vibrational entropy as well as local distortion. The fundamental idea of the scheme is making a new (renormalized) potential function for discretized space without changing the value of the partition function for continuous space. We show that the renormalized potential gives quantitative thermodynamic properties by using the scheme in Ni-based alloys.
While, the phase stability of bcc and hcp binary titanium alloys Ti-X (X = Mo, Nb, Al, and Zr) are also theoretically evaluated using first-principles calculations and a Debye model. The results are compared with the conventional CALPHAD data.
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| Free Research Field |
計算材料科学
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| Academic Significance and Societal Importance of the Research Achievements |
微細組織の制御や平衡状態の記述が、合金設計の基本となるが、それに必要なシミュレーション手法であるTTP図やフェーズフィールド法など、古典的な描像に基づく連続体モデルに対する一般的な問題として、計算に必要なパラメーターの正当化、実験との定量的な議論や特性予測の困難さが挙げられる。本研究により、これらの問題点を抜本的に解決し、整合析出物分散による耐熱超合金強化機構の、世界最高水準の精度を有する理論定量予測モデル構築を目指す。
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