Strain-induced dynamic precipitation of Mg17Al12 phases in Mg–8Al alloys sheets rolled at 748 K

Abstract

Strain-induced dynamic precipitation of Mg17Al12 phases was observed in large strain hot rolling of Mg–8Al alloys sheets. Our results show that Mg17Al12 phase precipitates in dynamic recrystallization of grains due to severe plastic deformation and the amount of secondary particles increases with increasing deformation strain. Two types of nanoscale Mg17Al12 phases precipitated inside dynamic recrystallized grains were observed. The growth of dynamic recrystallized grains is constricted by the pinning effect of β phase. The mechanical properties of rolled sheets are largely influenced by the increase of the deformation strain. It shows that the increase of ultimate tensile strength of rolled sheets can be segregated into two different stages, which are similar to the enhancement of dynamic recrystallization. The tendency of mechanical properties evolution of rolled sheets reveals that strain-induced precipitates have excellent hardening behavior and it can be considered as a promising way in improving mechanical properties of Mg alloys.