| Project/Area Number |
16K05964
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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 |
Materials/Mechanics of materials
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| Research Institution | Yamagata University |
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Principal Investigator |
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| Research Collaborator |
Koizumi Takayuki 山形大学, 技術系職員
Nakata Yuhei 山形大学, 大学院生
Shimada Tomoya 山形大学, 大学院生
Morita Shu 山形大学, 大学院生
Nibe Kento 山形大学, 大学院生
Kurumatani Anna 山形大学, 工学部生
Shika Yuta 山形大学, 工学部生
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| Project Period (FY) |
2016-04-01 – 2019-03-31
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| Project Status |
Completed (Fiscal Year 2018)
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| Budget Amount *help |
¥4,160,000 (Direct Cost: ¥3,200,000、Indirect Cost: ¥960,000)
Fiscal Year 2018: ¥910,000 (Direct Cost: ¥700,000、Indirect Cost: ¥210,000)
Fiscal Year 2017: ¥1,170,000 (Direct Cost: ¥900,000、Indirect Cost: ¥270,000)
Fiscal Year 2016: ¥2,080,000 (Direct Cost: ¥1,600,000、Indirect Cost: ¥480,000)
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| Keywords | 塑性構成式 / 金属材料 / 強化機構 / 結晶塑性 / 塑性論 / 粒界効果 / バウシンガー効果 / ひずみ勾配理論 / 結晶粒微細化効果 / 転位強化 / アルミニウム / 銅 / 結晶粒微細化 / 寸法効果 / 機械材料・材料力学 / 弾塑性論 |
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| Outline of Final Research Achievements |
The present study aims at developing a practical elastoplasticity model with intrinsic material length scales, Metals with fine crystal grains processed by severe plastic deformation (SPD) method are chosen as the target materials. Bauschinger tests (tension/compression tests) were performed to estimate roles of grain boundaries. The test results suggest that grain boundaries in SPD processed metals does not act as strong barriers to dislocation movement. Results of dislocation density measurements suggest that SPD processed metals are mainly strengthened by high density of dislocations rather than grain size or grain boundary effects. Furthermore, it was found that SPD processed metals possesses significant strain rate (or time) dependency. The information obtained in the present study gives foundations for constructing a new practical elastoplasticity theories.
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| Academic Significance and Societal Importance of the Research Achievements |
本研究は，材料の固有寸法因子を考慮した実用塑性変形理論を実験事実に基づいて開発することを目的としたものである．研究過程で，粒界の役割，結晶粒微細化過程における強度発現メカニズム，加工による大きなひずみ速度依存性出現などに関する新しい知見が多数得られた．これらは，従来認識されてい知見とは大きく異なるものである．本研究成果は，新しい塑性理論構築の基盤であるとともに，金属の巨視的な力学物性をより深く理解するための新しい研究潮流の端緒となることが期待される．
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