Hot compressive deformation behaviour and constitutive equations of Mg–Pb–Al–1B–0.4Sc alloy
Yuan Sun, Longke Bao, Yonghua Duan
Abstract
The hot compression features and microstructural evolution of Mg–Pb–Al–1B–0.4Sc alloy deformed at the strain rate range of 0.001–1 s−1 and the temperature range of 493–613 K were investigated by isothermal compression tests. The results show that the flow stress is significantly influenced by deformation conditions. The true stress decreases with the raised temperature or the reduced strain rate. The Zuzin-type model and Arrhenius-type constitutive model were employed to predict the flow behaviour of Mg–Pb–Al–1B–0.4Sc alloy. The values of MARE and RMSE in the Arrhenius-type model are 6.353% and 9.595, respectively, which are smaller than the 13.653% and 24.662 of the Zuzin-type model, indicating that the Arrhenius-type model is more suitable for predicting the flow stress of this alloy. The processing maps and microstructure show that the optimum strain rates and temperatures are 0.001–0.015 s−1 and 550–613 K, respectively.