2022 Fiscal Year Final Research Report
Hydrogen-assisted fatigue crack growth under gaseous environment interpreted by a thermally activated process
| Project/Area Number |
20K04161
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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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| Review Section |
Basic Section 18010:Mechanics of materials and materials-related
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| Research Institution | Kyushu University |
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Principal Investigator |
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| Project Period (FY) |
2020-04-01 – 2023-03-31
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| Keywords | 水素脆化 / 疲労き裂進展 |
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| Outline of Final Research Achievements |
Hydrogen penetrates metallic materials and causes "hydrogen embrittlement," which deteriorates their properties such as strength, ductility, etc. It has been reported that the crack propagation rate increases significantly in hydrogen environments under cyclic fatigue loading. However, the mechanism is still unknown, and its elucidation is essential for constructing a safe and secure hydrogen-based society. In this study, a fatigue crack growth acceleration model was established to unify the understanding of the cyclic loading frequency dependence and hydrogen temperature dependence of crack growth acceleration, focusing on the interaction between hydrogen atoms and dislocations emitted from the crack tip.
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| Free Research Field |
材料力学・破壊力学・強度
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| Academic Significance and Societal Importance of the Research Achievements |
我が国の国策でもある水素インフラや燃料電池自動車の普及拡大のためには “水素の影響を受けない材料”だけでなく“水素の影響を受ける材料”（例えば炭素鋼などの安価なBCC鉄鋼材料）の水素脆化の本質を見極めて安全・安心な設計指針を構築し、積極的に使用することが求められる。本研究成果はき裂進展の加速現象に着目し、そのミクロメカニズムを解明するものである。詳しくは水素によるマクロな特性変化の一つである疲労き裂進展加速現象の負荷速度依存性と水素ガス温度依存性をき裂先端部における転位と水素の熱的ミクロ相互作用により統一的に理解できることを明らかにした。
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