Abstract:The deformation behavior of AZ31B magnesium alloy as extruded under hot compression conditions was characterized in the temperature range of 200-400℃ and strain rate range of 0.001-1s^-1. The processing maps were obtained at different strains. The results show that the map exhibits flow instabilities as two domains. The domain at beyond 300℃ and strain rate of 1s^-1 appears with a peak efficiency of power dissipation about 56% occurring. This domain is expected to happen in a hot process, such as hot rolling, hot extrusion and hot forging. There is high efficiency of power dissipation at temperature beyond 350℃ and strain rate 0.001s^-1. Such domains suggest the occurrence of superplastic deformation. 

Key words: magnesium alloy; AZ31B; processing map; hot deformation; flow instability