Ti60合金的流动应力行为及本构关系

Flow stress behavior and constitutive relationship of Ti60 alloy

采用Thermecmaster-Z型热加工模拟试验机对Ti60合金试样进行等温恒应变速率压缩实验,研究合金在700~950℃温度范围,0.001~10 s-1应变速率范围的流动应力行为,并分别基于双曲正弦函数型Arrhenius方程和逐步回归法建立该合金的本构关系。结果表明,Ti60合金流动应力随应变速率增加和变形温度下降而增大,且因变形参数不同,流动应力呈现流动稳态型和流动软化型两种特征。基于双曲正弦函数型Arrhenius方程所建立的本构关系计算精度较低;基于逐步回归法和全实验温度段(700~950℃)所建立的本构关系具有较高的计算精度;而基于逐步回归法和温度分段(700~800℃和800~950℃)所建立的本构关系具有更高的计算精度。

Isothermal compression tests with constant strain rate of Ti60 alloy in the temperature range of 700-950℃,the strain rate range of 0.001-10 s-1 were conducted on the Thermecmaster-Z thermal simulator to study the flow stress behavior and establish the constitutive relation respectively based on hyperbolic sinusoidal Arrhenius equation and stepwise regression method.The results show that the flow stress of Ti60 alloy increases with the increase of strain rate and the decrease of deformation temperature,and the flow stress presents two characteristics:steady flow type and soft flow type for different deformation parameters.The constitutive relation based on hyperbolic sinusoidal Arrhenius equation is less accurate.The constitutive relation based on stepwise regression method and the whole experimental temperature period(700-950℃)has high calculation accuracy.The constitutive relation based on the method of stepwise regression and temperature section(700-800℃and 800-950℃)has higher calculation accuracy.