| Project/Area Number |
26630343
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| Research Category |
Grant-in-Aid for Challenging Exploratory Research
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| Allocation Type | Multi-year Fund |
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| Research Field |
Structural/Functional materials
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| Research Institution | Tokyo Institute of Technology |
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Principal Investigator |
Hosoda Hideki 東京工業大学, 精密工学研究所, 教授 (10251620)
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| Co-Investigator(Kenkyū-buntansha) |
INAMURA Tomonari 東京工業大学, 精密工学研究所, 准教授 (60361771)
TAHARA Masaki 東京工業大学, 精密工学研究所, 助教 (80610146)
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| Project Period (FY) |
2014-04-01 – 2016-03-31
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| Project Status |
Completed (Fiscal Year 2015)
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| Budget Amount *help |
¥3,900,000 (Direct Cost: ¥3,000,000、Indirect Cost: ¥900,000)
Fiscal Year 2015: ¥1,820,000 (Direct Cost: ¥1,400,000、Indirect Cost: ¥420,000)
Fiscal Year 2014: ¥2,080,000 (Direct Cost: ¥1,600,000、Indirect Cost: ¥480,000)
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| Keywords | 低温時効 / ナノ構造変化 / 微細組織 / 平衡相 / 非化学量論組成 / 機械的性質 / 金合金 / 構造・機能材料 / マルテンサイト変態 / 生体材料 / 超弾性合金 / 強化機構 / 第二相 |
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| Outline of Final Research Achievements |
Au-Ti binary and Co added ternary and quaternary alloy systems were used in this study. Several trials were done to fabricate single crystals using OFZ method, but no single crystal was obtained. Probably, some complex phase reactions containing peritectic reaction is related to solidification. Then, instead of single crystal, we used polycrystal alloys for further researches. It was found that Ti-rich offstoichiometric alloys exhibit good mechanical properties, and that aging behavior is not observed in Au-Ti binary alloys but Co-added alloys only. The equilibrium second phase is A15 AuTi3 in the binary system but it is changed to be L12 phase by Co addition. By TEM observations the size of this precipitates is relatively large from sub nm to a few microns, and no clear microstructural change is recognized such as APB and vacancy cluster. Then, the anomalous low temperature aging must be due to the L12 precipitates stabilized by Co addition.
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