| Project/Area Number |
15H05767
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| Research Category |
Grant-in-Aid for Scientific Research (S)
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| Allocation Type | Single-year Grants |
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| Research Field |
Structural/Functional materials
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| Research Institution | Kyoto University |
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Principal Investigator |
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| Co-Investigator(Kenkyū-buntansha) |
佐藤 眞直 (佐藤 真直) 公益財団法人高輝度光科学研究センター, 産業利用推進室, 主席研究員 (30360837)
Stefanus Harjo 国立研究開発法人日本原子力研究開発機構, 原子力科学研究部門 J－PARCセンター, 研究主幹 (40391263)
柴田 曉伸 京都大学, 工学研究科, 准教授 (60451994)
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| Project Period (FY) |
2015-05-29 – 2020-03-31
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| Project Status |
Completed (Fiscal Year 2019)
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| Budget Amount *help |
¥201,110,000 (Direct Cost: ¥154,700,000、Indirect Cost: ¥46,410,000)
Fiscal Year 2019: ¥26,130,000 (Direct Cost: ¥20,100,000、Indirect Cost: ¥6,030,000)
Fiscal Year 2018: ¥25,480,000 (Direct Cost: ¥19,600,000、Indirect Cost: ¥5,880,000)
Fiscal Year 2017: ¥25,610,000 (Direct Cost: ¥19,700,000、Indirect Cost: ¥5,910,000)
Fiscal Year 2016: ¥58,110,000 (Direct Cost: ¥44,700,000、Indirect Cost: ¥13,410,000)
Fiscal Year 2015: ¥65,780,000 (Direct Cost: ¥50,600,000、Indirect Cost: ¥15,180,000)
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| Keywords | 構造用金属材料 / 超微細粒 / 強度 / 延性 / 粒界 / 加工硬化 / 変形双晶 / マルテンサイト変態 |
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| Outline of Final Research Achievements |
The present research aimed to integrally clarify the mechanism of unique mechanical properties appearing in the bulk nanostructured metals (BNMs) composed of ultrafine grains with average grain sizes smaller than 1 um. Seven kinds of unique mechanical properties, i.e., 1) yield-drop phenomena occurring in all kinds of BNMs, 2) extra-hardening in Hall-Petch relationship, 3) softening by deformation and hardening by annealing, (4) strain-rate dependent deformation at ambient temperature, (5) huge Bauschinger effect, (6) activation of unusual slip systems in hexagonal metals, and (7) change in stability of deformation twinning and martensitic transformation, could be understood in the unified way based on the restriction of dislocation activities within small volume of each grain. Another unique deformation behavior was additionally found and all clarified. From the results, we could show a fundamental guidance principle for managing both high strength and large ductility in BNMs.
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| Academic Significance and Societal Importance of the Research Achievements |
「粒界だらけ」の新たな金属材料であるバルクナノメタルが示す特異な力学特性は、従来の教科書的理解では説明することができなかった。これらを統一的に理解した本研究の成果は、結晶性材料の塑性変形に新たな基礎的知見をもたらした点で学術的意義が高い。構造用金属材料は社会インフラを支えるために不可欠な材料であるが、輸送機器の軽量化や地震など災害時の安全性の向上のため、より高い強度とともに十分な延性・靭性が求められるようになっている。本研究の成果は、従来は両立することが難しかった高強度と高い延性・靭性を併せ持つ先進構造材料の実現を可能にするものであり、社会的意義も大きい。
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| Assessment Rating |
Verification Result (Rating)
A+
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Assessment Rating |
Result (Rating)
A+: Progress in the research exceeds the initial goal. More than expected research results are expected.
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