Flow behavior and microstructure evolution of TB8 alloy during hot deformation process

• Published in: Transactions of Nonferrous Metals Society of China Vol. 17; no. 6; pp. 1199 - 1204
• Main Author: 段园培 李萍 薛克敏 张青 王小溪
• Format: Journal Article
• Language: English
• Published: Elsevier Ltd 01.12.2007; School of Materials Science and Engineering, Hefei University of Technology, Hefei 230009, China
• Subjects: activation energy; flow stress; hot compressive deformation; microstructure; TB8 titanium alloy; 微观结构; 热压变形; 钛合金; hot compressive deformation; activation energy; flow stress; microstructure; TB8 titanium alloy
• ISSN: 1003-6326
• DOI: 10.1016/S1003-6326(07)60249-0

Hot compression tests of metastable β titanium alloy TB8 were carled out using a Gleeble-1500 thermal simulation testing machine in the temperature range of 750-1 100 ℃, at constant strain rate from 0.01 s^-1 to l S^-1 and with height direction reduction of 60%. Flow stress behavior and microstructure evolution during hot compression of TB8 alloy were investigated. The hyperbolic-sine-type constitutive model of TB8 alloy was obtained to provide basic data for determining reasonable forming process. The results indicate that hot deformation behavior of TB8 alloy is highly sensitive to the temperature and strain rate. An analysis of the flow stress dependence on strain rate and temperature gives a stress exponent of n=3.416 19 and a deformation activation energy of Ω=227.074 4 kJ/mol. According to the deformation microstructure, no dynamic recrystallization happens below r-phase transus temperature and as a result dynamic recovery is the predominant softening mechanism. On the other hand, the main softening mechanism is characterized as dynamic recrystallization at a slow strain rate above r-phase transus temperature.