2009 Fiscal Year Final Research Report
Clarification of the origin of embrittlement of beta-Ti alloys, and the improvement of their mechanical properties by focusing on the deformation induced omega-phase transformation
| Project/Area Number |
20760471
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| Research Category |
Grant-in-Aid for Young Scientists (B)
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| Allocation Type | Single-year Grants |
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| Research Field |
Structural/Functional materials
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| Research Institution | Osaka University |
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Principal Investigator |
HAGIHARA Koji Osaka University, 工学研究科, 助教 (10346182)
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| Project Period (FY) |
2008 – 2009
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| Keywords | β-Ti合金 / ω相 / 疲労 / 疲労軟化 / 単結晶 / 脆化 / 力学特性 |
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| Research Abstract |
We found the peculiar phenomenon of the dynamical precipitation of ω-phase during the cyclic deformation in a kind of β-Ti single crystals (Ti-35Nb-10Ta-5Zr) for the first time. We clarified that the crystal orientation (variant) of the formed ω-phase can be controlled by changing the Burgers vector of the dislocation moving during the cyclic deformation. This demonstrates that the formation mechanism of the cyclic deformation induced ω-phase is directly related to the to-and-fro motion of dislocations. In addition, we clarified that the β-Ti single crystal containing the oriented ω-phases shows strong plastic anisotropy depending on the loading orientation, which strongly affects the brittle features of the Ti-crystal in which the ω-phases were precipitated.
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