Role of dynamic recrystallization and grain growth on the formation of abnormal basal texture in a high-alloyed Mg-Al-Zn extruded alloy

Abstract

A commercial Mg-8.1Al-0.58Zn-0.27Mn alloy (mass%, AZ80) was extruded using different temperature and extrusion ratio. The microstructural development was thoroughly investigated by electron backscatter diffraction. A typical basal texture with the vertical alignment of the (0001) poles to the extrusion direction became main texture component regardless of the extrusion conditions. Notably, dynamically recrystallized grains, which had the parallel alignment of the (0001) poles to the extrusion direction, were formed at the initial stage of extrusion. However, such abnormally textured grains were consumed by basal-textured grains when the extrusion was performed at a relatively low temperature or using a high extrusion ratio of 50. In contrast, apparent intensity corresponding to the abnormal texture component was preserved during the extrusion at 400 °C using a relatively low extrusion ratio of 10. The low extrusion ratio facilitated the growth of the abnormally textured grains, which maintained a certain amount of the texture component having the parallel alignment of the (0001) poles to the extrusion direction.