| Project/Area Number |
07455058
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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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| Research Field |
Materials/Mechanics of materials
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| Research Institution | RITSUMEIKAN UNIVERSITY |
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Principal Investigator |
OHNAMI Masateru Ritsumeikan University, Faculty of Sci, & Eng., professor, 理工学部, 教授 (60066587)
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| Co-Investigator(Kenkyū-buntansha) |
FUJIYAMA Kazunari Toshiba corporation, Heavy Apparatus Engineering, Senior Engineer, 重電技術研究所, 主任
SAKANE Masao Ritsumeikan University, Faculty of Sci, & Eng., professor, 理工学部, 教授 (20111130)
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| Project Period (FY) |
1995 – 1996
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| Project Status |
Completed (Fiscal Year 1996)
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| Budget Amount *help |
¥7,300,000 (Direct Cost: ¥7,300,000)
Fiscal Year 1996: ¥1,400,000 (Direct Cost: ¥1,400,000)
Fiscal Year 1995: ¥5,900,000 (Direct Cost: ¥5,900,000)
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| Keywords | High temperature / Superalloy / Coating material / Creep / Fatigue / Crack / Ac potential method / Nondestructive test / クリープ疲労 / 交流 / 電位差法 / 有限要素法 |
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| Research Abstract |
Creep-fatigue tests were carried out using Inconel 738LC conventional cast and Rene80H directionally solidified Ni-base superalloys. Two strain waves were used in tests. They were fast-fast (pp) and slow-fast waves. The strain rate in fast straining was 0.1/s and that of slow straining 0.001%/s. Fatigue lives in cp tests were compared with those in pp tests and the effect of coating on fatigue life was also discussed. Ac potential method was applied to coated and uncoated specimens for detecting crack damage for the two types of specimens fatigued under pp and cp waves.
Fatigue lives under cp wave ware far smaller than those under cp wave for both kinds of specimens. Cracks were initiated at the surface of specimens and propagated into specimens in pp test for coated and uncoated specimens. Cracks were also initiated at the surface of specimens in cp tests for uncoated specimens but they initiated at the intercface between coating and base metal in cp test for coated specimens.
The crack damage was monitored for coated and uncoated specimens in pp and tests utilizing the rectangular ac current potential method and FFT analyzer. The potenitial method could detect the cracks initiated at the surface of specimens and at the interface with a sufficient accuracy. Especially, ac potential at low frequencies had a relative high accuracy. The ac potential method was available to the crack detection initiated at the interface between coating and base metal.
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