摘要
Hot compression tests of metastable β titanium alloy TB8 were carried out using a Gleeble-1500 thermal simulation testing machine in the temperature range of 750-1100 ℃, at constant strain rate from 0.01 s-1 to 1 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 Q≈227.074 4 kJ/mol. According to the deformation microstructure, no dynamic recrystallization happens below β-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 β-phase transus temperature.
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.
出处
《中国有色金属学会会刊：英文版》
EI
CSCD
2007年第6期1199-1204,共6页
Transactions of Nonferrous Metals Society of China
基金
Project(50405020) supported by the National Natural Science Foundation of China
关键词
钛合金
热压变形
应力
微观结构
TB8 titanium alloy
hot compressive deformation
flow stress
activation energy
microstructure
