Effect of Tube Extrusion Expander Shear on Recrystallization Behavior, Texture Evolution, and Mechanical Properties of Hot Deformed Mg-3Al-1Zn Alloy

In this paper, a new fabrication technique for Mg-3Al-1Zn (AZ31) magnesium alloy tube, called tube extrusion expander shear (TEES), was proposed based on the existing extruded shear (ES) technique. The finite-element modeling (FEM) was used to simulate the forming process of TEES. The electron back-scattered diffraction (EBSD) was used to study the microstructures and textures evolution of AZ31 magnesium alloy during TEES process. The mechanical properties of the formed tube were tested. The results show that TEES process can effectively refine the grain size and weaken the basal texture. The hardness and plasticity of the tube processed by TEES process are significantly improved, the maximum elongation is 15%, and the hardness is 78 HV. Based on the analysis of intragranular misalignment axis (IGMA), the evolutions of twins in the TEES process were studied. It was found that twins and basal slip were the main deformation modes in the early deformation zone. With development of TEES process the twins disappear and multiple sliding systems were activated. The results show that the turning and shearing zones of TEES process are beneficial to the activation of multiple slip systems.