Hot compression deformation behavior and a modified physically-based constitutive model of Cu-6 %Ag alloy

In order to reveal the flow characteristics of Cu-6 %Ag alloy on the condition of hot deformation, the isothermal compression experiments are carried out at the temperatures of 973-1123 K under strain rates of 0.01-10 s(-1). The effects of deformation condition on the hot compression deformation behavior are investigated. The low instability strain (epsilon(i)) behavior at high strain rate (10 s(-1)) is discussed in this paper. According to the experiment results and analyses, the deformation twinning and inhomogeneous grains are thought to be the possible reasons for low strain cracking. Then, a modified physically based constitutive model is established. The strain for maximum softening rate (epsilon*) is quoted in the constitutive equation which is proved that there is a nearly linear relationship between ln epsilon* and lnZ. What's more, the correlation coefficient (R) and the average absolute relative error (AARE) are used to evaluate the accuracy of the established constitutive model. The values of R and AARE are 0.99612 and 3.47 %, respectively, which show that the modified constitutive model can exactly reveal the flow stress of Cu-6 %Ag alloy.