2010 Fiscal Year Final Research Report
Perfect superelasticity by dispersion of effective precipitate routed through brittle phase in biomedical titanium alloy
| Project/Area Number |
20360310
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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 |
Structural/Functional materials
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| Research Institution | Tokyo Institute of Technology |
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Principal Investigator |
HOSODA Hideki Tokyo Institute of Technology, 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)
WAKASHIMA Kenji 東京工業大学, 精密工学研究所, 教授 (70016799)
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| Project Period (FY) |
2008 – 2010
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| Keywords | インテリジェント材料 / 安全・安心材料 / 組織制御 |
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| Research Abstract |
There is no effective method of microstructural control to suppress the slip deformation that competes with superelastic deformation inβ-Titanium superelastic alloy, though this alloy is a candidate biomedical superelastic alloy. The superelastic deformation in β-titanium alloy is, therefore, not a perfect one ; plastic strain remains after deformation. We propose a new heat-treatment method to precipitate fine α-phase for strengthening that is nucleated at fine ω-phase. The ω-phase brings extreme brittleness and is not used in usual heat-treatment of titanium alloy, whereas it is used as a medium for ω-phase nucleation in our new method. 800MPa in strength and perfect shape recovery are achieved by a three-step heat-treatment : 773K (fine ω precipitation)→1023K (fine α precipitation at ω)→1123K(erasing ω) in Ti-Mo-X (X=Al and Mn). In addition, a low-temperature heat-treatment around 373K as the fourth step improved mechanical property.
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