A Simplified Approach for Developing Constitutive Equations for Modeling and Prediction of Hot Deformation Flow Stress

A comparative study was carried out on the appropriateness of hyperbolic sine, power, and exponential descriptions of Zener–Hollomon parameter (Z) in prediction of high-temperature flow stress by consideration of the effect of strain. It was shown that the main problem of the conventional strain compensation approach is the implementation of the constitutive equations to find the strain-dependent material constants, especially the hot deformation activation energy (Q), at constant strain values, which arises from the change in the microstructure of the material at a given strain for different deformation conditions (different Z values). Subsequently, a simplified approach for each constitutive equation, mainly by taking Q from the peak stress analysis, was proposed to solve this issue. This also resulted in significantly better prediction abilities for unseen deformation conditions and effectively simplified the required calculations.