Improved strength and ductility of magnesium alloy below micro-twin lamellar structure

The effect of {10−12} micro-twin lamellar structure on the mechanical properties of magnesium alloy has been examined. It has been found that the detwinning behavior effectively increases the flow stress of Mg alloy, and this strengthening effect becomes more significant with the volume fraction of twin lamellae increasing for the annealed materials. Meanwhile, the refined microstructure caused by the micro-twin lamellae plays an important role in improving the ductility of materials. But a latent Hall–Petch hardening correlated to grain refinement by twin lamellae was not substantiated by experiments, indicating strengthening from twin boundaries is relatively less pronounced below twin lamellae of micrometer scale. Here, the high density of twin boundaries and the high volume fraction of twins are considered as the structural characteristics of the critical {10−12} twin lamellae, which can effectively optimize strength and ductility of magnesium alloy.