Microstructure evolution and mechanical properties of AZ31 magnesium alloy by ultra-high frequency transient induction heating

Abstract

AZ31 magnesium alloy plate with excellent mechanical properties is quickly prepared by rolling and electromagnetic induction heating (REIH) in this study. After five cycles of electromagnetic induction heating (EIH), The plasticity of the magnesium sheet increased from 7.7 % to 12.5 %, while the strength remained relatively constant. The high strength can be attributed to the reduced in average grain size and the increased dislocation density. As the number of EIH cycles increases, dislocations are gradually distributed uniformly, crystal spacing is increased, rheological stresses on the (10–11) and (10–12) planes are reduced, and the <c+a> dislocation slip system is activated during deformation. The reason is that EIH generates an electric current (electron wind) in the rolled AZ31 magnesium alloy, causing electrons to collide with lattice atoms, thereby transferring momentum to the atoms and facilitating dislocation motion. This unique atomic diffusion path induces the change of the localized crystal structure and enhances texture strength. This offers a novel technological route for the fabrication of magnesium alloys with high strength and plasticity.