The effect of temperature on microstructure and hardness of AZ80 Mg alloy during equal channel angualr pressing

AZ80 Mg alloy was processed at 320℃ and 200℃ by equal channel angular pressing.At 320℃,the grain size was decreased at previous two passes and then increased in the subsequent passes.At 200℃,both the density of dislocation and twinning were increased at previous two passes with the hardness dramatically increased.After 4 passes with route Bc,the grain size was refined to 200nm in most of areas,but the hardness slightly increased due to the interaction of grain refinement strengthening and texture softening.