Improvement of Mechanical Properties in Ti Alloys Using Heterogeneous Elemental Distribution
Most of practical titanium alloys contain some alloying elements such as Nb and Mo, which are prone to segregation. In this study, we have tried to change the distribution of these alloying elements in two types of titanium alloys through thermomechanical treatment. Ti-Al-Nb base inter-metallic alloy,Ti25Al-HNb-2Mo-1Fe (mol ％) ,was hot-forged and barrolled at 1273K in the (B2+α2) two phase region. After the rolling,Nb and/or Mo-rich region forms swirly band structure. Due to the segregation of these β stabilizing elements, we can obtain heterogeneous distribution of α2 phase particles after the heat treatment at 1273K. Room temperature tensile elongation value was improved from nearly 0 to 6％, which can be attributed to this heterogeneous distribution of α2 phase particles. We also applied similar thermomechanical treatment on corrosion resistant (Hype Ti-12Mo (mass ％) alloys,and obtained Mo-rich swirly band-like structures. This led to heterogeneous precipitation of to phase after aging at temperatures lower than 723K due to the local variation in β phase stability. Room temperature tensile elongation value after aging at 523K for 3. 6ks was improved from 4％ to 19％ with tensile strength of around l000MPa.
Thermomechanical treatment segregation tensile elongation orthorhombic phase omega phase
Satoshi Emura Xiaohua Min Seiichiro Ii Kaneaki Tsuzaki Koichi Tsuchiya
National Institute for Materials Science,Tsuknba 305-0047,Japan
国际会议
The 12th World Conference Titanium(第十二届世界钛会 Ti-2011)
北京
英文
536-539
2011-06-19（万方平台首次上网日期，不代表论文的发表时间）