2020 Fiscal Year Final Research Report
Establishment of single grain boundary strength evaluation and atomistic mechanism investigation on grain boundary hydrogen embrittlement
| Project/Area Number |
18H01344
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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 | Kansai University |
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Principal Investigator |
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| Project Period (FY) |
2018-04-01 – 2021-03-31
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| Keywords | 水素脆性 / 結晶粒界 / 電子顕微鏡 / 強度評価 |
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| Outline of Final Research Achievements |
The fracture along grain boundaries (GBs), which is frequently observed in high-strength poly-crystalline materials subjected to hydrogen environments, has been qualitatively attributed to the hydrogen embrittlement (HE) of the GBs. Is the GB-HE theory correct? Motivated by this fundamental question, a quantitative GB-HE measurement method using a micro-specimen containing a single GB is studied in detail. The key point of the study is the hard coating layer attached locally to the specimen surface. With this procedure, it is confirmed that the amount of plastic deformation before the onset of GB fracture is effectively reduced. Further, an in-situ STEM-EELS analysis of GB hydrogen using a nano electron probe is conducted under a hydrogen environment.
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| Free Research Field |
材料力学
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| Academic Significance and Societal Importance of the Research Achievements |
水素インフラの爆発的な普及は，水素による金属材料の脆化（水素脆性）に起因する不具合・事故案件の増大を必然的に招く．一方，水素脆性の基礎的研究は質・量の面においてまだまだ多くの余地がある．本課題で取り上げた多結晶材料中の結晶粒界における水素脆性もその典型例であり，詳細な破壊メカニズムを精密な実験により直接的に評価する，という試みは少ない．本研究の成果は，粒界そのものを対象とした破壊実験方法の確立や，粒界における水素の物理化学的解析手法の確立へ向けた大きな前進である．
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