2020 Fiscal Year Final Research Report
Clarification of hardenability improvement mechanism based on borocarbides formation behavior in the grain boundary amorphous phase
| Project/Area Number |
18K04752
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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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| Review Section |
Basic Section 26040:Structural materials and functional materials-related
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| Research Institution | Kyushu Institute of Technology |
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Principal Investigator |
Tokunaga Tatsuya 九州工業大学, 大学院工学研究院, 准教授 (40457453)
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| Co-Investigator(Kenkyū-buntansha) |
惠良 秀則 九州工業大学, 大学院工学研究院, 教授 (00127987)
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| Project Period (FY) |
2018-04-01 – 2021-03-31
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| Keywords | 粒界偏析 / 粒界析出 / 状態図 |
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| Outline of Final Research Achievements |
In this study, the effect of alloying elements on the segregation behavior of boron at the grain boundaries of iron was evaluated using the Hillert’s parallel tangent law based on the grain boundary phase model, and it was shown that the grain boundary segregation behavior of boron and alloying elements can be understood from the viewpoint of thermodynamic stability of alloying element borides. A similar tendency was also confirmed in the grain boundary segregation behavior of carbon or nitrogen and alloying elements. Furthermore, as a result of evaluating the grain boundary precipitation behavior by Davies-Uhlmann kinetic treatment using the obtained data on grain boundary segregation behavior, it was suggested that the precipitation behavior changes through changes in the thermodynamic stability of compounds such as boride depending on the type and amount of alloying elements added, resulting in a change in hardenability.
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| Free Research Field |
材料組織学
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| Academic Significance and Societal Importance of the Research Achievements |
鋼における焼入れ性に関しては，最新の実験機器などを利用して得られた各種元素の粒界偏析挙動や粒界における化合物の生成挙動の詳細な実験データが蓄積されつつあり，これらの定量データと焼入れ性との相関について種々考察されてはいるが，未だ解明されていないのが現状である．本研究は，上記の粒界における偏析挙動や化合物生成挙動と焼入れ性との相関について，熱力学と速度論とのカップリングによる従来とはまったく異なる視点でのアプローチでそのメカニズムを解明しようというものであり，得られた成果は，実用鉄鋼材料の材質造りこみにおいて学術的および実用的に重要な焼入れ性向上メカニズムの理解につながり，波及効果も大きい．
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