| Project/Area Number |
19H02024
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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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| Review Section |
Basic Section 18010:Mechanics of materials and materials-related
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| Research Institution | Shizuoka University |
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Principal Investigator |
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| Co-Investigator(Kenkyū-buntansha) |
岩田 太 静岡大学, 電子工学研究所, 教授 (30262794)
藤井 朋之 静岡大学, 工学部, 准教授 (30377840)
中澤 謙太 静岡大学, 工学部, 助教 (50824520)
塩澤 大輝 神戸大学, 工学研究科, 准教授 (60379336)
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| Project Period (FY) |
2019-04-01 – 2022-03-31
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| Project Status |
Completed (Fiscal Year 2021)
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| Budget Amount *help |
¥17,030,000 (Direct Cost: ¥13,100,000、Indirect Cost: ¥3,930,000)
Fiscal Year 2021: ¥4,030,000 (Direct Cost: ¥3,100,000、Indirect Cost: ¥930,000)
Fiscal Year 2020: ¥4,030,000 (Direct Cost: ¥3,100,000、Indirect Cost: ¥930,000)
Fiscal Year 2019: ¥8,970,000 (Direct Cost: ¥6,900,000、Indirect Cost: ¥2,070,000)
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| Keywords | 粉末冶金 / 表面改質 / 金属疲労 / 光計測 / 破壊力学 / 高輝度放射光 |
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| Outline of Research at the Start |
本研究では，大きさの異なるミクロ組織をマクロに周期配置させた3次元ヘテロ構造材料の高機能化メカニズムを解明する．とくに「強さ」と「しなやかさ」の両立という特異な力学特性を解明するため，ヘテロ構造材料のミクロ・マクロ変形の双方を捉えるマルチスケール計測法を構築し，3次元ヘテロ構造における材料損傷挙動の時間的変化を評価（4次元材料損傷評価）する．
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| Outline of Final Research Achievements |
Metallic materials having a heterogeneous structure (HS), which consists of a coarse-grained structure surrounded by a network structure of fine equiaxed grains, were fabricated to achieve high strength and ductility. 4D evaluation of damage was conducted for the HS materials with high performance by multi-scale measurement.
The fatigue limit was increased by the HS design due to the grain refinement. To improve their fatigue properties, thermomechanical processing (TMP) was performed. The average size of the grains in the fine-grained structures was preferentially decreased by TMP. Applying TMP to CP titanium having a HS increased its fatigue life due to greater resistance to the initiation of fatigue crack as a result of grain refinement. In contrast, the crack growth rates for the HS material for long cracks were constantly higher, and its threshold stress intensity range were lower compared to a material with a homogenous coarse-grained structure.
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| Academic Significance and Societal Importance of the Research Achievements |
しなやかな粗大粒組織の周りに強い微細粒組織をネットワーク状に周期配置させた「3次元ヘテロ構造材料」の特異な力学特性を，ミクロ・マクロ変形の双方を捉えるマルチスケール計測法によって明らかにした．これまでは「いかに均一かつ微細な結晶粒を作るか」が常識とされていたが，このような3次元ヘテロ構造材料の実用化によって各種機械構造物の信頼性向上が期待される．さらに，3次元ヘテロ構造材料の多機能性は機械構造物の小型軽量化にも寄与し，省エネルギー化の促進が期待される．
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