Flow stress equation of AZ31 magnesium alloy sheet during warm tensile deformation

The uniaxial warm tensile tests were carried out under a strain rate range of 0.1–0.0001 s−1 at a temperature range of 423–573 K in order to evaluate the flow stress of AZ31 magnesium alloy sheet. The flow stress curves analyzing by Fields–Backofen constitutive equation can only give a good fit to the measured stress–strain relationship at the work-hardening stage. A new mathematical model containing a softening item s is used to calculate the flow stress curves. The results indicate that this modeling can approach better at the softening stage of the flow stress than that of the Fields–Backofen equation.