Hot workability characteristics of magnesium alloy AZ80—A study using processing map

The deformation behavior of as-cast AZ80 alloy is investigated by compression test with gleeble-1500 thermal simulator. The tests are performed in the temperature range of 200–500 °C and the strain rate of 0.001–20 s−1. It is found that the flow stress behavior is described by the hyperbolic sine constitutive equation in which the average activation energy of 154.6 kJ/mol is calculated. Through the flow stresses behavior, the processing maps are calculated and analyzed according to the dynamic materials model. In the processing map the variation of the efficiency of the power dissipation is plotted as a function of temperature and strain rate. The maps exhibit a domain of dynamic recrystallization (DRX) occurring at the temperature range of 420–500 °C and in the strain rate range of 10−3 s−1 to 10−2 s−1 which are the optimum parameters for hot working of the alloy. The instability zones of flow behavior can also be recognized by the maps.