2012 Fiscal Year Final Research Report
A unified evaluation of fatigue crack growth rate in different gas environments and its application limits
| Project/Area Number |
22560085
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| Research Category |
Grant-in-Aid for Scientific Research (C)
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| Allocation Type | Single-year Grants |
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| Section | 一般 |
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| Research Field |
Materials/Mechanics of materials
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| Research Institution | Kyushu University |
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Principal Investigator |
ODA Yasuji 九州大学, 工学研究院, 助教 (20091340)
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| Research Collaborator |
NISHIMOTO Atsushi 九州大学, 大学院・工学府
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| Project Period (FY) |
2010 – 2012
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| Keywords | 金属疲労 / き裂伝ぱ速度 / 水素 / すべり / その場観察 |
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| Research Abstract |
High acceleration of the fatigue crack growth rate of carbon steel in hydrogen environment is due to transition from ductile fracture to quasi-cleavage(QC) fracture and to increase in area ratio of QC fracture surface. Loading frequency influences the transition behavior and QC area ratio. There exist conditions where ductile fracture has high proportion of the fracture surface and low acceleration of fatigue crack growth rate in nitrogen environment as well as in hydrogen. Usual fatigue crack growth test reveals not only ductile fracture surface but intergranular fracture surface even at the beginning of QC fracture. It was not successful to attempt to define the slip behaviordirectly related to the crack growth rate
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