2010 Fiscal Year Final Research Report
Near-Threshold Fatigue Crack Growth Characteristics and Quantitative Evaluation of Relevant Fracture Surface of Directionally Solidified Superalloy in a Vacuum at Elevated Temperatures
| Project/Area Number |
20560074
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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 | Osaka University |
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Principal Investigator |
TSUJI Masahiro Osaka University, 工学研究科, 助教 (10132630)
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| Project Period (FY) |
2008 – 2010
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| Keywords | 高温疲労 / 下限界 / 見かけの下限界 / 真空中 / 破壊力学 / 破面解析 / 一方向凝固超合金 |
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| Research Abstract |
Fatigue crack growth experiments in the near-threshold region were conducted in a vacuum and in the air for directionally solidified Ni-based superalloy at elevated temperature. The so-called "apparent threshold" behavior occurred by K_<max> increased, and it was found that the crack growth behaviors below that had the temperature, loading frequency, and loading waveform dependences. Observations of fracture surfaces after those experiments were made by AFM. Fractal analysis was applied to the data and quantitative evaluations for those fracture surfaces were attempted. It was found that fractal dimensions increased as K_<max> increased in a vacuum.
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