Hot deformation and processing maps of as-extruded Mg-9.8Gd-2.7Y-0.4Zr Mg alloy

The deformation behavior of as-extruded Mg-9.8Gd-2.7Y-0.4Zr Mg alloy is investigated by compression test with Gleeble-3500 thermal simulator at temperature of 648-723 K and strain rate of 0.01-5 s(-1). It is found that the flow stress behavior is described by the hyperbolic sine constitutive equation in which the determined average activation energy is 229.5 kJ/mol. Through the flow stresses behavior, the processing maps describing the variation of power dissipation efficiency, is constructed as a function of temperature and strain rate. The processing maps exhibit a domain of dynamic recrystallization (DRX) occurring at the temperature of 420-450 degrees C and strain rate of 0.01-0.1 s(-1), corresponding to the optimum hot working window. The instability zones of flow behavior are also recognized from the maps. (C) 2013 Elsevier B.V. All rights reserved.