Constitutive Modeling for Predicting Flow Stress Behavior of Ti–6.5Al–3.5Mo–1.5Zr–0.3Si Alloy during Thermo-Mechanical Processing

The flow stress behavior of Ti–6.5Al–3.5Mo–1.5Zr–0.3Si alloy during thermo-mechanical processing is predicted by constitutive material modeling. To develop constitutive models of Ti–6.5Al–3.5Mo–1.5Zr–0.3Si alloy, isothermal uniaxial compression tests are performed under the different deformation conditions of 930–1050°C and 0.001–10 s–1. Using the experimental flow stress data, new versions of the modified Zerilli–Armstrong model, the strain-compensated Arrhenius-type model and modified Johnson–Cook model are constructed in the α + β two phase and β phase fields, respectively. The determination coefficient and average absolute relative error of the proposed version of modified Zerilli–Armstrong model are 0.9917 and 5.95%, respectively. Meanwhile, the modified Johnson–Cook model records the determination coefficient of 0.9907 and average absolute relative error of 7.53%, and the strain-compensated Arrhenius-type model records 0.9873 and 7.39%. This indicates that the phenomenologically modified Zerilli–Armstrong model is more appropriate than the strain-compensated Arrhenius-type model and modified Johnson–Cook model for predicting the high-temperature flow stress behavior of Ti–6.5Al–3.5Mo–1.5Zr–0.3Si alloy.