摘要
The hot deformation behavior of beta C titanium alloy in β phase field was investigated by isothermal compression testson a Gleeble？3800 thermomechanical simulator. The constitutive equation describing the hot deformation behavior was obtained anda processing map was established at the true strain of 0.7. The microstructure was characterized by optical microscopy （OM）,scanning electron microscopy （SEM） and electron back-scattered diffraction （EBSD） technique. The results show that the flow stressincreases with increasing strain rates, and decreases with increasing experimental temperatures. The calculated apparent activationenergy （167 kJ/mol） is close to that of self-diffusion in β titanium. The processing map and microstructure observation exhibit adynamic recrystallization domain in the temperature range of 900-1000 ℃ and strain rate range of 0.1-1 s^-1. An instability regionexists when the strain rate is higher than 1.7 s^-1. The microstructure of beta C titanium alloy can be optimized by proper heattreatments after the deformation in the dynamic recrystallization domain.
利用Gleeble-3800热模拟试验机对beta C钛合金进行等温压缩试验,研究其在β相区的热变形行为。得到了描述热变形行为的本构方程,获得了真应变为0.7时的加工图。采用光学显微镜、扫描电子显微镜和电子背散射技术对变形显微组织进行表征。结果表明:流变应力随着应变速率加快而增大,随着试验温度的升高而减小。计算得到的表观激活能为167 k J/mol,接近β钛的自扩散激活能。加工图和显微组织观察表明在温度为900~1000°C和变形速率为0.1~1 s^(-1)的区间存在一个动态再结晶区。加工图显示,当变形速率大于1.7 s^(-1)时,beta C钛合金发生不稳定变形。Beta C钛合金在动态再结晶区变形后,经合适的热处理,显微组织可以被优化。
