2018 Fiscal Year Final Research Report
Evaluation of the calculation method of grain boundary segregation energy by diffusion rate theory model
| Project/Area Number |
15K06429
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| Research Category |
Grant-in-Aid for Scientific Research (C)
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| Allocation Type | Multi-year Fund |
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| Section | 一般 |
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| Research Field |
Physical properties of metals/Metal-base materials
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| Research Institution | Japan Atomic Energy Agency |
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Principal Investigator |
Ebihara Kenichi 国立研究開発法人日本原子力研究開発機構, システム計算科学センター, 研究主幹 (40360416)
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| Co-Investigator(Kenkyū-buntansha) |
鈴土 知明 国立研究開発法人日本原子力研究開発機構, システム計算科学センター, 研究主幹 (60414538)
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| Research Collaborator |
Yamaguchi Masatake
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| Project Period (FY) |
2015-04-01 – 2019-03-31
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| Keywords | 照射誘起粒界リン偏析 / 混合格子間原子対 / 空孔リン複合体 / 侵入型リン原子 / 第一原理計算 / 分子動力学法 / キネティックモンテカルロ法 / 拡散レートモデル |
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| Outline of Final Research Achievements |
Grain boundary(GB) segregation of embrittlement elements influences irradiation embrittlement of steel structural materials and the segregation depends on the GB segregation energy. Recently, it is reported that the simulated value of the segregation energy is different from that evaluated from experiments. In this study, from the hypothesis that this difference is due to the experimental evaluation ignoring the element distribution around GBs, we attempted to make a model for calculating phosphorus (P) distribution around GBs and GB segregation based on the atomic process. In making the model, we evaluated the diffusion coefficient of the mixed dumbbell of a P atom and an iron atom and made clear the GB P segregation process that is unknown previously. However, we found that it is additionally necessary to make clear the de-trapping process of P atoms from GBs.
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| Free Research Field |
材料計算科学
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| Academic Significance and Societal Importance of the Research Achievements |
リンの粒界偏析過程の考察において、粒界周辺の格子のひずみ及び熱による粒界自身のゆらぎが、リン原子の粒界への移動過程に大きく影響し、特に、粒界周辺において、単独で移動しにくい置換型原子に変わってしまうことが明らかになった。このような粒界周辺での不純物原子の移動への影響は従来あまり考えられていないものであることから、本研究での結果は、これまでの不純物の粒界偏析の考え方を修正するものであると考えられる。
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