| Project/Area Number |
11555048
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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 | 展開研究 |
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| Research Field |
設計工学・機械要素・トライボロジー
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| Research Institution | IWATE UNIVERSITY |
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Principal Investigator |
IWABUCHI Akira IWATE UNIVERSITY, MECHANICAL ENGINEERING, PROFESSOR, 工学部, 教授 (00005555)
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| Co-Investigator(Kenkyū-buntansha) |
YOSHINO Yusuhiro JAPANESE SCIENCE PROMOTION, RESEARCH FELLOW, 工学部, 日本学術振興会特別研究員
CHIBA Akihiko IWATE UNIVERSITY, WELFARE SYSTEM ENGINEERING, ASSOCIATE PROFESSOR, 工学部, 助教授 (00197617)
SHIMIZU Tomoharu IWATE UNIVERSITY, MECHANICAL ENGINEERING, ASSOCIATE PROFESSOR, 工学部, 助教授 (10240649)
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| Project Period (FY) |
1999 – 2001
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| Project Status |
Completed (Fiscal Year 2001)
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| Budget Amount *help |
¥13,500,000 (Direct Cost: ¥13,500,000)
Fiscal Year 2001: ¥1,400,000 (Direct Cost: ¥1,400,000)
Fiscal Year 2000: ¥3,000,000 (Direct Cost: ¥3,000,000)
Fiscal Year 1999: ¥9,100,000 (Direct Cost: ¥9,100,000)
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| Keywords | HARDNESS / HARDNESS TESTER / CRYOGENIC TEMPERATURE / GM-REFRIGERATOR / SUPERCONDUCTORS / FRICTION TESTER / TEMPERATURE DEPENDENCE / FRACTURE TOUGHNESS / トライボロジー / ビッカース硬さ |
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| Research Abstract |
In this work we developed the new Vickers-type cryogenic hardness tester, using GM-refrigerator. The old one was cooled with liquid helium, but the temperature and temperature rising rate could not be controlled because of the evaporation of liquid helium. Therefore, we introduced a GM-refrigerator to control in a vacuum chamber. The performance of the hardness tester was acceptable. The problem was not to cool a specimen at around 4 K due to the contact resistance of conduction from the second cooling stage head of the refrigerator and the specimen. The temperature was cooled down at around 30 K in this tester.
We measured the hardness not only metallic specimens such as SUS316L stainless steel, but also high temperature superconductors such as YBCO, and ((Nd,Eu,Gd)BaCuO). The latter was used as the bulk magnet, but it breaks down easily with Lorentz force during magnetizing. The fracture toughness K_<IC> was evaluated from the hardness and the crack size initiated from an indented scar during hardness test. Generally, hardness was increased with decreasing temperature monotonically with rather great scatter, but the fracture toughness was slightly decreased with temperature. For example, the hardness of (Nd,Eu,Gd)BaCuO was 9,800 MPa at 40 K. The fracture toughness depends on the crystal plane because there were many inherent cracks on the (100) plane and it was easier for cracks to propagate.
We also equipped the pin-on-desk type friction tester with a reciprocating sliding motion in the chamber. The temperature of the specimen was valid from 40 K to room temperature. Unfortunately, we could not obtain the frictional date due to lack of time. The performance of the frictional tester was examined at 40 K and room temperature, and we are satisfied. Later, we will obtain the temperature dependence of coefficient of friction of materials.
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