Influence of extrusion method on the microstructure and mechanical properties of formed magnesium alloy tubes

In this work, a tube extrusion-shear-expanding (TESE) process was proposed to develop a high-performance magnesium alloy thin-walled tube, and then a comparison was made with the direct extrusion (DE) process. The microstructure and mechanical properties of magnesium alloy tubes under different processes were tested and analyzed. Numerical simulations were conducted by using DEFORM (TM)-3D software to predict the effective stresses, forming loads, and effective strains during the forming of magnesium alloy tubes. Compared with DE process, the TESE process with high effective stresses, effective strains, and forming loads generates a severe plastic deformation of the tube, leading to a more obvious grain refinement effect on the fabricated tube with a tensile strength of around 293 MPa and an elongation of around 15%. The results show that the TESE process has obvious advantages. The critical shear force and dynamic recrystallization further refine the grains and weaken the basal texture strength. The comprehensive performance of magnesium alloy tube is improved.