The effect of LPSO phase on hot deformation behavior and dynamic recrystallization evolution of Mg-2.0Zn-0.3Zr-5.8Y alloy

The effect of long period stacking ordered (LPSO) phase on the hot deformation behavior, dynamic recrystallization (DRX) evolution and workability of Mg-2.0Zn-0.3Zr-5.8Y alloy was studied by compression test. Compression experiments were performed at a temperature range of 300-500 degrees C and a strain rate range of 0.001-1 s(-1) on a Gleeble 1500D thermo-mechanical simulator. Based on regression analysis for Arrhenius type equation of flow behavior, the apparent average activation energy of deformation was determined as Q=292.97 KJ/mol. The DRX kinetic model of Mg-2.0Zn-0.3Zr-5.8Y alloy was established as X-DRX = 1-exp[-1.8818(epsilon-epsilon(c)/epsilon*)(2 2407)]. The DRX kinetic model agreed with the microstructures of the alloy at any deformation conditions. It was found that LPSO phase delayed the DRX of Mg-2.0Zn-0.3Zr-5.8Y alloy at the deformation temperature range of 300-350 degrees C and the strain rate range of 0.001-0.01 s(-1), the deformation temperature range of 300-450 degrees C and the strain rate range of 0.1-1 s(-1). Based on the flow stress behavior, the processing maps were calculated and analyzed according to the dynamic material model (DMM). The established processing maps at different strains exhibited deformation domains where complete DRX occurred (400-500 degrees C at 0.001-0.01 s(-1), 500 degrees C at 0.1-1 s(-1)), which were the optimum parameters for hot working of the alloy. (C) 2013 Elsevier B.V. All rights reserved,