A comparative study on constitutive modeling of hot deformation flow curves in AZ91 magnesium alloy

Modeling the flow curves of materials at elevated temperatures is the first step in mathematical simulation of the hot deformation processes of them. In this work a comparative study was provided to examine the capability of three different constitutive equations in modeling the hot deformation flow curves of AZ91 magnesium alloy. For this, the Arrhenius equation with strain dependent constants, the exponential equation with strain dependent constants and a recently developed simple model (developed based on a power function of Zener-Hollomon parameter and a third order polynomial function of ε power a constant number) were examined. Root mean square error (RMSE) criterion was used to assess the modeling performance of the examined constitutive equations. Accordingly, it was found that the Arrhenius equation with strain dependent constants has the best performance for modeling the hot deformation flow curves of AZ91 magnesium alloy. The results can be further used in mathematical simulation of hot deformation manufacturing processes of tested alloy.