Influence of power dissipation value and deformation activation energy on the recrystallization in the compression deformation behavior of Mg-Li-Zn-Y alloy☆

Abstract

The thermal compression deformation behavior of Mg-6Li-11Zn-2.5Y alloy was systematically investigated by using the isothermal hot compression tests using the Gleeble-3500 thermal mechanical physical simulation system with the conditions of the temperature of 513–593 K and the strain rate of 0.01–10 s–1. The constitutive model and thermal processing map were established. The variation pattern of the unstable region under different strains was analyzed and the safe processing region was determined. The influence of different power dissipation values and deformation activation energies on the dynamic recrystallization mechanism was clarified. The results demonstrate that the deformation activation energy is 156.08 kJ/mol. The unstable region gradually expands from the low temperature and low strain region to the high temperature and high strain region with the strain increasing. In the unstable region, adiabatic shear band pear in α-Mg phase, of which the main reason is the poor processing formability in the unstable region. The dominant nucleation mechanism is discontinuous dynamic recrystallization under the conditions of high power dissipation and low deformation activation energy. While, under the conditions of low power dissipation and high deformation activation energy, the nucleation mechanism is mainly driven by the particle stimulated nucleation.