(南昌航空大学 航空制造工程学院，南昌 330063)
摘 要: 使用Gleeble-3500型热模拟实验机进行TC4-DT钛合金等温恒应变速率热压缩实验，得到不同变形条件下TC4-DT钛合金的真应力-真应变曲线，分析了变形温度与应变速率对合金流变应力的影响；研究了热变形过程中TC4-DT钛合金的微观组织演变规律。结果表明：TC4-DT钛合金流变应力随着温度的升高和应变速率的降低而降低，并且变形过程中伴随着加工硬化以及动态回复与动态再结晶；不同条件下合金微观组织演变存在较大差异，随着变形温度的升高，等轴α相含量不断减少，直到几乎消失；但微观组织中逐渐产生针状马氏体，其含量随着变形温度的升高而不断增加。此外，基于Arrhenius方程建立了TC4-DT钛合金高温本构方程，同时构建了热加工图，为合金热加工提供参考。
关键字: TC4-DT钛合金；热变形；本构方程；热加工图
（School of Aeronautical Manufacturing Engineering, Nanchang Hangkong University, Nanchang 330063, China）
Abstract:The isothermal constant strain rate thermal compression experiment of TC4-DT titanium alloys were carried out by Gleeble-3500 thermal simulation machine, the true stress-true strain curves of TC4-DT titanium alloys under different conditions were acquired, the effects of temperature and strain rate on the flow stress were analyzed. The microstructure evolution of TC4-DT titanium alloy during hot deformation was investigated. The results show that the flow stress of TC4-DTtitanium alloy decreases with the increase of temperature and the decrease of strain rate. The deformation process is accompanied by work hardening, dynamic recovery and dynamic recrystallization, and the microstructures of the alloys are greatly different under different conditions .With the increase of temperature, the content of equiaxed α phase decreases continuously until it almost disappears, but acicular martensite gradually appears in the microstructure, and the content of acicular maternsite increases with the increase of temperature. In addition, the high temperature constitutive equation of TC4-DT titanium alloy was established based on Arrhenius formula, and the processing map of TC4-DT titanium alloy is constructed, which provides the reference for the hot working of the alloy.
Key words: TC4 - DT titanium alloy; thermal deformation; constitutive equation; processing map
