| Project/Area Number |
17K06064
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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 | Nihon University |
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Principal Investigator |
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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 |
¥4,940,000 (Direct Cost: ¥3,800,000、Indirect Cost: ¥1,140,000)
Fiscal Year 2019: ¥650,000 (Direct Cost: ¥500,000、Indirect Cost: ¥150,000)
Fiscal Year 2018: ¥650,000 (Direct Cost: ¥500,000、Indirect Cost: ¥150,000)
Fiscal Year 2017: ¥3,640,000 (Direct Cost: ¥2,800,000、Indirect Cost: ¥840,000)
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| Keywords | 損傷評価 / 寿命評価 / 微視損傷 / 結晶方位差 / 高Cr鋼 / 微視損傷モデル / 結晶粒回転 / TypeⅣ破壊 / 微視損傷形成モデル / 高温力学特性 / 余寿命推定 / 解析・評価 / 機械材料・材料力学 |
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| Outline of Final Research Achievements |
To understand the physical mechanism of the interactive effects of creep and fatigue, it is important to clarify the damage mechanisms around the crack. In the present study, the experiments of creep-fatigue crack growth tests and the quantitative analysis of damage by measuring Vickers hardness were conducted to understand the interactive effects of creep and fatigue on the crack growth characteristic. Additionally, by observing the material microstructure using EBSD, damage mechanisms were clarified. As a result, it was found that creep effect contributes the expansion of damage region and fatigue effect increases the degree of damage. Interaction of these effects resulted in the occurrence of unstable transition region on the characteristic of creep-fatigue life.
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| Academic Significance and Societal Importance of the Research Achievements |
本研究が提案する方法は，ミクロ構造のデジタル解析技術を走査型電子顕微鏡（SEM）観察へ応用したものであり，透過型電子顕微鏡（TEM）に比べて簡便に観察を実施できることが特徴である。また，TEMを構造材料へ適用する場合，その狭い限られた範囲の評価から全体を推測する必要があるが，本研究が提案する方法は直接的な損傷評価を行うことが可能である。さらに，本申請課題の目標である「微視損傷発現機構シミュレータ」の構築は，単なる損傷の状態監視技術にとどまらず，損傷の定量的予測を行うものであり，これまでには無かった新たな価値を生み出すものと考えている。
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