| Project/Area Number |
05452130
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| Research Category |
Grant-in-Aid for General Scientific Research (B)
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| Allocation Type | Single-year Grants |
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| Research Field |
Materials/Mechanics of materials
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| Research Institution | RITSUMEIKAN UNIVERSITY |
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Principal Investigator |
OHNAMI Masateru Faculty of Science and Engineering, Ritsumeikan University, 理工学部, 教授 (60066587)
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| Co-Investigator(Kenkyū-buntansha) |
FUJIYAMA Kazunari Heavy Apparatus Engineering, Toshiba Corporation, 重電技術研究所, 主任
SAKANE Masao Faculty of Science and Engineering, Ritsumeikan University, 理工学部, 教授 (20111130)
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| Project Period (FY) |
1993 – 1994
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| Project Status |
Completed (Fiscal Year 1994)
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| Budget Amount *help |
¥6,900,000 (Direct Cost: ¥6,900,000)
Fiscal Year 1994: ¥1,200,000 (Direct Cost: ¥1,200,000)
Fiscal Year 1993: ¥5,700,000 (Direct Cost: ¥5,700,000)
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| Keywords | Superalloy / Directionally solidified / High temperature / Greep-fatigue / Constitutive relation / Anisotropy of elastic constant / クリーブ疲労 |
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| Research Abstract |
This study carried out low cycle fatigue tests with fast-fast and slow-fast strain waves for Inconel 738LC coated specimens at 1123K in air. The low cycle fatigue life of coated specimens was compared with that of uncoated specimens and the creep-fatigue damage was evaluated by means of A.C.potential method. The main conclusions obtained are as follows.
1.The low cycle fatigue life of coated specimens is slightly smaller than that of uncoated specimens but there is no large difference in the fatigue life between the two types of the specimens. Cracks were initiated at the outer surface of the coating materials and propagated into the base metal in fast-fast tests. The crack density of the coated specimen was far smaller in comparison with the uncoated specimens.
2.The fatigue life in slow-fast tests was about 60% of that in fast-fast test for the coated specimens. For the coated specimens in slow-fast test, cracks were initiated at the interface between the coating and base materials and propagated into the base materials. Crack density was also far smaller in the coated specimens.
3.A.C.potential method is proved to be applicable to the detection for the cracks initiated at the outer surface and the interface of coating. Low frequency of A.C.was more sensitive to the macro crack detection.
4.The increase in the high frequency A.C.potential corresponds with the crack density while that of low frequency with the maximum crack length.
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