Constitutive Equations, Processing Maps, and Microstructures of Pb-Mg-Al-B-0.4Y Alloy under Hot Compression

Hot compression behaviors of Pb-Mg-Al-B-0.4Y alloy under strain rate of 0.001-1 s(-1) and temperature of 493-613 K were performed by employing hot compressing tests. According to the experimental stress-strain curves, as the strain increases, the flow stress increases firstly, then reaches the peak stress, and finally decreases to a steady state. Constitutive equations in traditional Arrhenius model and improved Arrhenius model in multi-linear regression were used to predict the flow stress of Pb-Mg-Al-B-0.4Y alloy. The values of MARE and RMSE in the traditional Arrhenius model are 11.780 and 21.169%, respectively, which are larger than 7.227 and 7.447% of the improved Arrhenius model, indicating that the predicted accuracy of the improved Arrhenius model is more accurate. The hot processing maps under the experimental conditions were established. Based on processing maps and microstructure observation, the optimum processing parameters are 0.001 s(-1) <= _epsilon(over dot) <= 0.01 s(-1) and 587 K <= T <= 613 K.