| Project/Area Number |
08455285
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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 |
Physical properties of metals
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| Research Institution | HOKKAIDO UNIVERSITY |
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Principal Investigator |
MARUKAWA Kenzaburo Hokkaido Univ., Grad.School of Eng., Pro., 大学院・工学研究科, 教授 (20001191)
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| Co-Investigator(Kenkyū-buntansha) |
TSUCHIYA Koichi Toyohasi Univ.of Tech., Fac.of Eng., Lec., 生産システム工学系, 講師 (50236907)
TAKEZAWA Kazuyoshi Hokkaido Univ., Grad.School of Eng., Ins., 大学院・工学研究科, 助手 (80001311)
TAKAMA Toshihiko Hokkaido Univ., Grad.School of Eng., Ass.Pro., 大学院・工学研究科, 助教授 (40001309)
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| Project Period (FY) |
1996 – 1997
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| Project Status |
Completed (Fiscal Year 1997)
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| Budget Amount *help |
¥6,600,000 (Direct Cost: ¥6,600,000)
Fiscal Year 1997: ¥1,000,000 (Direct Cost: ¥1,000,000)
Fiscal Year 1996: ¥5,600,000 (Direct Cost: ¥5,600,000)
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| Keywords | shape memory effect / martensitic transformation / rubber effect / stabilization phenomenon / degree of order / short range order / aging effect / 形状記憶合金 / ゴム状弾性 |
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| Research Abstract |
In order to improve characteristics of shape memory alloys for a variety of applications, it is necessary to study the nature of martensitic transformation more precisely, because the shape memory effect is brought about by martensitic transformation. Concerning this transformation in copper based shape memory alloys, two important problems remains unsolved so far, which are the rubber effect and the stabilization phenomenon of martensites. The present authors have recently presented a new view that the change in short range order (SRO) due to aging is the cause of these phenomena. The purpose of the present study is to examine this view more closely by experiments and theoretical calculations. The results are summarized in the following.
(1) In copper alloys, the time evolution of the rubber effect and the stabilization due to aging was measured. It was found that these effects become prominent as the aging proceed, and that they have almost the same time constant with each other.
(2) The change in short range order was traced by electrical resistivity measurements and by x-ray diffraction measurements. It was affirmed that the time constant of the SRO change is approximately the same as those of the rubber effect and the stabilization. This results supports the view mentioned above.
(3) The SRO was calculated theoretically as a function of aging temperature in order to clarify the condition of appearance of the rubber effect and the stabilization. It was found that the rubber effect should be most prominent at temperatures around the transition temperature of order-disorder. The dependence of the stabilization on the aging temperature was also clarified.
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