(北京航空材料研究院，北京 100095)
摘 要: 通过等温恒应变速率压缩实验研究铸态TB6钛合金在温度为800~1 100 ℃，应变速率为10−3~1 s−1条件下的热变形行为。结果表明：应变速率对铸态TB6合金流变应力的影响最显著，其次是变形温度，而应变的影响作用最小。在低温高应变速率下，流变应力曲线呈连续软化特征，而在高温低应变速率下，流变应力曲线呈稳态流变特征。铸态TB6合金的热变形激活能为200 kJ/mol，接近纯钛β相的自扩散激活能，表明在实验条件范围内主要发生动态回复过程。在Arrhenius方程基础上考虑了应变对流变应力曲线的影响，建立了能准确描述铸态TB6钛合金流变应力曲线的双曲正弦本构关系。
关键字: 铸态TB6钛合金；热变形；本构关系
as-cast TB6 alloy
（Beijing Institute of Aeronautical Materials, Beijing 100095, China）
Abstract:The hot deformation behavior of as-cast TB6 alloy was investigated by isothermal constant strain rate compression test at temperatures of 800−1 100 ℃ and strain rates of 10−3−1 s−1. The results show that the flow stress of as-cast TB6 alloy is greatly affected by strain rate, followed by temperature and the effect of strain is the weakest. The flow stress curves display continuous softening characteristics at low temperatures and high strain rates, while display steady flow characteristics at high temperatures and low strain rates. The activation energy is determined to be 200 kJ/mol which is close to that of self-diffusion of β phase in pure titanium, and it shows that the dynamic recovery takes place dominantly during hot deformation. Considering the effect of strain, an improved hyperbolic sine constitutive relationship is established based on the Arrhenius equation that can accurately describe the flow stress of as-cast TB6 alloy.
Key words: as-cast TB6 alloy; hot deformation; constitutive relationship
