| Project/Area Number |
02452244
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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 |
金属材料(含表面処理・腐食防食)
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| Research Institution | Tokyo Institute of technology, Precision and Intelligence Laboratory (P&IL) |
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Principal Investigator |
NUNOMURA Shigetomo Tokyo Institute of Tech., P&IL., Prof., 精密工学研究所, 教授 (60016764)
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| Co-Investigator(Kenkyū-buntansha) |
ONO Masashi Tokyo Institute of Tech., P&IL., former Associate., 精密工学研究所, 助手 (10211145)
KUMAI Shinji Tokyo Institute of Tech., P&IL., Associate., 精密工学研究所, 助手 (00178055)
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| Project Period (FY) |
1990 – 1991
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| Project Status |
Completed (Fiscal Year 1991)
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| Budget Amount *help |
¥7,500,000 (Direct Cost: ¥7,500,000)
Fiscal Year 1991: ¥2,300,000 (Direct Cost: ¥2,300,000)
Fiscal Year 1990: ¥5,200,000 (Direct Cost: ¥5,200,000)
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| Keywords | Fusion reactor materials / Fatigue properties / Micro specimen / Materials testing / Indentation method / Size effect / 寸法効果 / 核融合炉材料 |
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| Research Abstract |
The fatigue characteristics are of fundamental importance when choosing a structural material, especially when deciding upon the material for the fusion reactor wall where long term safety is of primary importance. It is well known that a metal may fail under imposition of a stress considerably lower than the normal breaking stress, if that stress is applied in a cyclic manner. However, the fatigue properties of highly irradiated wall materials have not been studied in detail. This is primarily due to the shortage of materials which are suitable for such applications. In common type fatigue test, a larger size specimen used to be required compared to other mechanical tests. Nevertheless in the case of fusion reactor wall materials, the limited irradiation space for the specimen requires the use of TEM disk size specimens in mechanical tests to cooperate with safety regulations.
In this research two types of miniature fatigue test method have been developed in response to the requirements of the fusion reactor wall materials development program. It is known that the fatigue strength evaluated by the axial loading test is independent of the specimen size, while that evaluated by the bend test or torsion test is dependent upon the size of specimen. Then new type of gripping system for the axial, tension-tension, fatigue testing of TEM size specimens has been developed. An alignment toot assists to grip the miniature specimen. The miniature tension-tension fatigue test method seems to provide reliable S-N curves for two austenitic stainless steels.
An indentation method has also been developed to determine fatigue properties. A hard steel ball or ceramic ball was used for cyclically loading the specimen and an S-N curve was subsequently obtained. The merit of this method is primarily simple handling. S-N curves obtained from four materials by this indentation method compared well with those obtained from the rotary bend fatigue test employing a standard size specimen.
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