An Improved Physically-Based Constitutive Model for the Hot Deformation Behavior of GH4698 Superalloy by Considering Dynamic Softening Mechanism

The hot deformation behaviors of GH4698 superalloy are studied by the hot compression tests performed over a range of strain rates (0.001–10  \(s^{ - 1}\) ) and deformation temperatures (1020–1200 \(^\circ {\text{C}}\) ). The results show that the flow stress is significantly affected by deformation temperature and strain rate. As the deformation temperature increases or the strain rate decreases, the flow stress decreases. In the work hardening-dynamic recovery stage, a physically-based constitutive equation for flow stress is obtained from the stress-dislocation relation. In the subsequent dynamic recrystallization stage, the flow stress is predicted by employing the dynamic recrystallization kinetics in the constitutive model. The stress-strain curves of the studied superalloy predicted by the established models are in good agreement with measured data, which indicates that the developed physically-based constitutive model enjoy the high accuracy in characterizing the hot deformation behaviors of GH4698 superalloy.