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

澄清β-Ti合金的脆化根源，并通过关注变形引起的欧米茄相变来改善其机械性能

• 批准号: 20760471
• 负责人: HAGIHARA Koji
• 金额: $ 2.75万
• 依托单位: Osaka University
• 依托单位国家: 日本
• 项目类别: Grant-in-Aid for Young Scientists (B)
• 财政年份: 2008
• 资助国家: 日本
• 起止时间: 2008 至 2009
• 项目状态: 已结题
• 来源: https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-20760471/
• 关键词: β-Ti合金; ω相; 疲労; 疲労軟化; 単結晶; 脆化; 力学特性; 塑性異方性; 相安定性; 応力誘起

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.

本文首次在一种β-Ti单晶（Ti-35 Nb-10 Ta-5 Zr）中发现了循环变形过程中ω相动态析出的特殊现象。通过改变位错运动的Burgers矢量，可以控制所形成的ω-相的晶体取向。这说明循环变形诱发ω相的形成机制与位错的往复运动直接相关。此外，我们还阐明了β-Ti单晶中含有取向的ω-相时，随加载方向的不同，β-Ti单晶表现出很强的塑性各向异性，这种各向异性强烈地影响着ω-相析出的Ti单晶的脆性特征。

项目成果

極低酸素分圧雰囲気下でのTi単結晶の帯溶融育成

极低氧分压气氛下Ti单晶的区域熔融生长

• 发表时间: 2008
• 期刊: 日本金属学会誌 72
• 作者: 萩原幸司;橘孝洋;佐々木啓太;吉田良由;白河直樹;長澤亨;成島尚之;中野貴由
• 通讯作者: 中野貴由

Ti-15Mo-5Zr-3Al単結晶の育成と圧縮変形挙動

Ti-15Mo-5Zr-3Al单晶的生长和压缩变形行为

• 发表时间: 2009
• 作者: 李尚勲;萩原幸司;中野貴由
• 通讯作者: 中野貴由

Single-crystal growth and plastic deformation behaviour of a Ti-15Mo-5Zr-3Al alloy for biomedical application

生物医学应用 Ti-15Mo-5Zr-3Al 合金的单晶生长和塑性变形行为

• 发表时间: 2009
• 期刊: Journal of physics 165
• 作者: S. -H. Lee;K. Hagihara;M. -H. Oh;T. Nakano
• 通讯作者: T. Nakano

Controlling factors on the fatigue behaviour of Ti-Nb-Ta-Zr alloys single crystals

Ti-Nb-Ta-Zr合金单晶疲劳行为的控制因素

• 发表时间: 2009
• 期刊: Proceedings of PFAM18 (Processing and fabrication of Advanced Materials)
• 作者: K.Hagihara;T.Nakano;et al.
• 通讯作者: et al.

Oxygen distribution in titanium single crystal fabricated by floating-zone method under extremely low oxygen partial pressure

极低氧分压浮区法制备钛单晶中的氧分布

• 发表时间: 2009
• 期刊: Materials transactions 50
• 作者: K. Hagihara;T. Tachibana;K. Sasaki;Y. Yoshida;N. Shirakawa;T. Nagasawa;T. Narushima;T. Nakano
• 通讯作者: T. Nakano