Comparison of Constitutive Models and Microstructure Evolution of GW103K Magnesium Alloy during Hot Deformation

The characteristics of constitutive behavior and microstructure evolution of GW103K magnesium alloy were investigated via hot compression tests at a strain rate of 0.001-1 s(-1) and a temperature of 623-773 K. The rheological stress of GW103K alloy decreased with increasing temperature or decreasing strain rate during hot deformation. Three models including the Johnson Cook (JC) model, the strain-compensated Arrhenius (SCA) model and back-propagation neural networks (BPNN) were applied to describe the constitutive relationships. Subsequently, the predictability and precision of the models were compared by evaluating the correlation coefficient (R), root mean square errors (RMSE), and relative errors (RE). Compared with the JC and SCA models, the BPNN model was more efficient and had higher prediction accuracy in describing flow stress behavior. Furthermore, EBSD maps confirmed that magnesium alloy easily causes dynamic recrystallization (DRX) during hot deformation. The volume fraction and size of DRX grains increased with decreasing strain rate and/or increasing temperature.

Automated summary

In this study, the constitutive behavior and microstructure evolution of GW103K magnesium alloy were investigated through hot compression tests. The results showed that the rheological stress of the alloy decreased with increasing temperature or decreasing strain rate during hot deformation. Three models were applied to describe the constitutive relationships, and the BPNN model was found to be more efficient and accurate in describing flow stress behavior compared to the other models. EBSD maps confirmed the occurrence of dynamic recrystallization in the magnesium alloy during hot deformation, with the volume fraction and size of recrystallized grains increasing with decreasing strain rate and/or increasing temperature.