Constitutive Equations for Describing the Hot Compressed Behavior of TC4-DT Titanium Alloy

Isothermal hot compression tests of TC4-DT titanium alloy were performed under temperatures of 1203-1293 K and strain rates of 0.001-10 s^-1. The purpose of this study is to develop a new high-precision modified constitutive model that can describe the deformation behavior of TC4-DT titanium alloy. Both the modified strain-compensated Arrhenius-type equation and the modified Hensel-Spittel equation were established by revising the strain rate. The parameters in the above two modified constitutive equation were solved by combining regression analysis with iterative methods, which was used instead on the traditional linear regression methods. In addition, both the original strain-compensated Arrhenius-type equation and Hensel-Spittel equation were established to compare with the new modified constitutive equations. A comparison of the predicted values based on the four constitutive equations was performed via relative error, average absolute relative error (AARE) and the correlation coefficient (R). These results show the modified Arrhenius-type equation and the modified Hensel-Spittel equation is more accurate and efficient with a similar prediction accuracy. The AARE-value of the two modified constitutive equation is relatively low under various strain rates and their fluctuation is small as the strain rate changes.