Microstructure and mechanical properties in an AZ31 magnesium alloy sheet fabricated by asymmetric hot extrusion

Hot extrusion is one of the effective methods to decrease grain size of materials. As grains are finer, the mechanical properties of materials can be improved. It was found that the grains of magnesium alloy AZ31 sheets could be reduced to 3 μm by a differential speed rolling at an elevated temperature. In the present study, one-pass asymmetric hot extrusion performed at temperature of 673 K was applied to fabricate an AZ31 magnesium alloy sheet in order to introduce great shear strain during the primary processing. The textures, microstructures and mechanical properties at room temperature along the extrusion planes from top surface to bottom surface were examined. The experimental results showed that the asymmetric hot extrusion effectively weakened the basal texture and improve the ductility at room temperature.