New Phenomenological Model to Predict High-Temperature Flow Stress Curves at High Strain Rates

Abstract

In this study, a new phenomenological equation has been presented to predict high-temperature flow stress curves of metallic materials at industrially relevant deformation conditions with negligible flow softening. To this end, a nonlinear estimation of strain-hardening rate versus strain curves was employed to obtain flow stress as a function of strain. To prove the validity and competency of the presented model, flow stress curves of Alloy 800\xa0H obtained at temperatures from 850°C to 1,050°C and at strain rates of 5\xa0s−1 and 10\xa0s−1 were used. The evaluation of the mean error of flow stress revealed that the presented model can give a precise estimation of stress-strain curves of Alloy 800\xa0H at high strain rates. The Johnson-Cook and logarithmic power models were also used to show the accuracy of the presented model at different deformation conditions. It was discovered that the presented model can provide a more accurate estimation of flow stress curves for the alloy of this study.