Effect of initial microstructures on microstructures and properties of extruded AZ31 alloy

Abstract

The raw materials for extruded preparing magnesium alloy tubes were electromagnetic stirring (EMS) AZ31 magnesium alloy billets and conventional casting (CC) AZ31 magnesium alloy billets. According to the findings, the mechanical properties of the EMS extrusion tubes were far superior to those of the CC extrusion tubes. The key explanation was that the samples of EMS billet had variable initial grain sizes and twin boundaries, which provide additional nucleation sites for DRX nucleation during the extrusion process. With the increase of extrusion temperature and extrusion ratio, the elongation of the tube is further improved. During the extrusion process, the recrystallization mechanism changed from continuous dynamic recrystallization (CDRX) to discontinuous dynamic recrystallization (DDRX).