用Gleeble-1500型热模拟机研究TC4-DT钛合金在850～1100℃、应变速率0.001～10 s－1、变形量70％条件下的高温压缩热变形行为，分析了该合金的流变应力行为以及显微组织演变规律，建立了该合金的本构关系模型以及热加工图。研究结果表明， TC4-DT 钛合金在两相区和β相区的热变形激活能分别为544.03 kJ· mol－1和264.32 kJ· mol－1 ，分别大于纯α相和纯β相的自扩散激活能，表明TC4-DT钛合金热变形由高温扩散以外的过程控制。在两相区热变形时，原始组织发生了不同程度的球化，且变形温度越低球化效果越好。在β相区热变形时，低应变速率下（0.001～0.1 s－1）主要发生动态再结晶，而高应变速率（1～10 s－1）下主要发生动态回复，动态再结晶行为受到抑制。 TC4-DT钛合金的失稳区主要分布在低温高应变速率区域，变形温度主要在850～940℃，应变速率主要在0.1～10 s－1，功率耗散率η值小于28％。
Hot compressive deformation of TC4-DT titanium alloy was carried out with the hot-simulation machine of Gleeble-1500 at the deformation degree of 0.7, over the range of deformation temperature from 850 ℃ to 1 100 ℃, strain rate from 0.001 s-1 to 10 s-1 .The deformation behavior and microstructure evolution were analyzed, meanwhile the constitutive model and hot processing map were set up.The results reveal that the deformation activation energy of TC4-DT titanium alloy are 544.03 kJ · mol-1 in two-phase region and 264.32 kJ · mol-1 in βphase region respectively, larger than self diffusion activation energy of pureαandβphase, which shows the thermal deformation of TC4-DT titanium alloy is controlled by high temperature diffusion process.When the alloy is deformed in two-phase region, the globularization intensity increases obviously with temperature decreasing.In the βphase region, the dynamic recrystallization occurs at low strain rate ( 0.001 s -1 to 0.1 s-1 ) and the dynamic recovery occurs at high strain rate (1 s-1 to 10 s-1 ) .Furthermore, the instability zone of TC4-DT titanium alloy is mainly distributed in the low temperature and high strain rate region where the deformation temperature range from 850℃to 940℃, the strain rate range from 0.1 s-1 to 10 s-1 , and the power dissipation rate (η) is lesser than 28%.
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