Hot deformation behaviour of as-cast Mg–2Zn–1Mn alloy in compression: a study with processing map

Abstract

The deformation behaviour of as-cast Mg-2Zn-1Mn alloy in the temperature range 300-500°C and in the strain rate range 0.001-100 s⁻¹ has been studied using processing maps. For obtaining the processing map, the variation of the efficiency of power dissipation given by [2m/(m+1)] where 'm' is the strain rate sensitivity, is plotted as a function of temperature and strain rate. The map exhibited a domain of dynamic recrystallization (DRX) occurring at 450°C and 0.1 s⁻¹ which are the optimum parameters for hot working of the alloy. The material exhibits grain boundary cracking domain with a higher efficiency at temperatures higher than 450°C and at lower strain rates. At strain rates higher than 3 s⁻¹, the material undergoes flow localization which has to be avoided in mechanical processing for obtaining consistent properties.