Effect of heat treatment on microstructures and mechanical properties of extruded-rolled AZ31 Mg alloys

The deformation behaviors of extruded-rolled (ER) AZ31 Mg alloys with different rolling reduction and heat treatment were investigated. The results show that the accumulation of rolling reduction increases the density of twins, and refines the grain structures, which are in accordance with the enhanced strength and degraded plasticity. Tensile strength and plasticity of the alloy depend mainly on rolling reduction, while heat treatment temperature plays a more important role than heat treatment time at the same rolling reduction. With the increase of rolling reduction, the plasticity becomes more sensitive than strength on heat treatment. Recrystallization of extruded-rolled alloys will occur easily with deformation increasing, which is induced by addition of distortion energy.