Ti-6Al-2Zr-1Mo-1V合金热塑性流变行为的变参数Arrhenius模型表征

在Gleeble-1500热模拟试验机上进行多组热压缩试验,获得Ti-6Al-2Zr-1Mo-1V合金在温度1073～1323K、应变速率0.01～10s-1下的真应力-应变数据,基于此分析工艺参数对流变应力演变的影响规律,识别应力-应变曲线的动态再结晶型和动态回复型软化特征及其出现时机。引入不含应变影响的传统Arrhenius型本构方程,将其进一步拓展使用,在不同应变量条件下,通过多元线性回归计算与多项式拟合,求解获得Ti-6Al-2Zr-1Mo-1V合金形变表观激活能Q、材料常数n、α及结构因子A等参量对应变的响应规律,从而建立Ti-6Al-2Zr-1Mo-1V合金含应变、温度及应变速率影响的变参数流变应力本构方程。模型预测值与实验值对比显示最大相对误差为4.55%,最大平均误差为2.19%。

Characterization of thermoplastic flow behavior for Ti-6Al-2Zr-1Mo-1V alloy by Arrhenius model with variable parameters

The true stress-strain curves of Ti-6Al-2Zr-1Mo-1V alloy were achieved by a series of isothermal compression tests under the deformation temperatures of 1073-1323K and the strain rates of 0.01-10s-1,which would be taken as the basic data for investigating the influence of processing parameters on the flow stress and the microstructure as well as the properties of dynamic recrystallization(DRX) and dynamic recovery(DR).The Arrhenius constitutive relation which the strain not involved was collected to develop the constitutive equation.Through adopting multivariate regression and polynomial fitting,the law of deformed activation energy of the apparent Q,materials constant n,α and structural factor A on the strain was obtained,and the model of flow stress with variable parameters was established.To evaluate model,the relative error between the experimental and predicted results is calculated,and the maximum inaccuracy of the first one is 4.77%,while the maximum average is 2.19%.