| Project/Area Number |
17H03415
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| Research Category |
Grant-in-Aid for Scientific Research (B)
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| Allocation Type | Single-year Grants |
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| Section | 一般 |
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| Research Field |
Structural/Functional materials
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| Research Institution | Osaka University |
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Principal Investigator |
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| Co-Investigator(Kenkyū-buntansha) |
趙 研 大阪大学, 工学研究科, 講師 (00633661)
永瀬 丈嗣 大阪大学, 超高圧電子顕微鏡センター, 准教授 (50362661)
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| Project Period (FY) |
2017-04-01 – 2020-03-31
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| Project Status |
Completed (Fiscal Year 2019)
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| Budget Amount *help |
¥17,680,000 (Direct Cost: ¥13,600,000、Indirect Cost: ¥4,080,000)
Fiscal Year 2019: ¥1,950,000 (Direct Cost: ¥1,500,000、Indirect Cost: ¥450,000)
Fiscal Year 2018: ¥2,730,000 (Direct Cost: ¥2,100,000、Indirect Cost: ¥630,000)
Fiscal Year 2017: ¥13,000,000 (Direct Cost: ¥10,000,000、Indirect Cost: ¥3,000,000)
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| Keywords | 構造・機能材料 / 社会基盤構造材料 / ハイエントロピー合金 / 転位 / 格子欠陥 |
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| Outline of Final Research Achievements |
AlxCoCrFeNi and CoCr1+yFeNi1-yMn non-equiatomic fcc high entropy alloys with ultrafine-grained microstructure of which average grain sizes are 0.7μm and 1.4μm can be obtained through conventional cold rolling followed by recrystallization treatment. This is because the NiAl and sigma phases are precipitated rapidly along the grain boundaries of the fcc matrix and suppress the grain growth. As a result, an excellent balance between strength and ductility can be obtained by the thermomechanical treatment. The yield stress and grain size of the ultrafine-grained alloys satisfy the Hall-Petch relationship. Moreover, the grain growth behavior is in good agreement with the modified Zener-Smith model.
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| Academic Significance and Societal Importance of the Research Achievements |
5種類以上の構成元素を等量配合するのではなく、あえて非等量配合とすることで、結晶粒界、せん断帯といった格子欠陥部に第2相を高速析出させ、そのピン止め効果により超微細粒を得る、というアイディアは、申請者が世界で初めて考案したものである。単純な圧延再結晶処理で超微細粒化が達成できる点が長所である。論文発表、国際会議発表を通じて、このアイディアは世界の知るところとなり、現在では、類似の研究に関する報告が後を絶たない。
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