Role of Grain Refinement Mechanism on Microstructure and Performance in AZ31B Alloy During Interactive Alternating Forward Extrusion (AFE) Process

Abstract

In this study, interactive alternate forward extrusion (AFE) experiments with varying number of extrusion passes of AZ31 magnesium alloy were carried out. The evolution of microstructure, and texture and their effects on the mechanical properties were studied. The results show that with the increase of loading passes, the grains are significantly refined, and the dynamic recrystallisation (DRX) structure is uniformly distributed in the product, which is the main reason for the increase in microhardness, compressive strength and failure strain. Further, slip and twinning induced DRX behaviour are considered to be the main deformation methods in the early stage of deformation. Whereas continuous DRX is considered to be the main deformation methods for the change in grain morphology in the later stage. During the extrusion process, the deflection angle of the base pole decreases. Finally, the fibre texture is formed; the texture strength is significantly reduced because of the effect of recrystallisation. The AZ31 magnesium alloy interactive AFE process is discussed with respect to the technological experiment and the microstructure deformation, thus providing a vital scientific basis for further application.