Recrystallisation, concurrent precipitation, and texture development in cold forged Mg-6Al-3Sn magnesium alloy

Abstract

ABSTRACT The present investigation has highlighted the effect of annealing temperatures from 200°C to 300°C on the recrystallisation behaviour and texture evolution of cold-forged Mg-6Al-3Sn (AT63) magnesium alloy. A new microstructure with a modified grain size was formed under different annealing conditions. The dominant nucleation sites of recrystallised grains were found at twin/grain-boundary and twin/twin intersections and twin interiors. Recrystallisation was incomplete at an annealing temperature of 200°C, even for a prolonged time. It may be ascribed to concurrent precipitation (Mg17Al12 and Mg2Sn), which interferes with grain boundary motion during recrystallisation. However, at high annealing temperatures, the volume of these precipitates was very low. They did not effectively hinder the recrystallisation process, resulting in faster recrystallisation kinetics. The average grain size was extensively refined from 85 to ∼7 µm with cold forging and annealing approach. The cold-forged deformation texture of AT63 alloy shows the typical basal structure (0002) in nature. The recrystallised material retained the basal texture after isothermal annealing of cold-forged AT63 alloy.