Influences of Expanding Angles on Extrusion-Shearing-Expansion Processing of AZ31 Magnesium Alloy Thin-Walled Tubes

Abstract

To research the influence mechanisms of expanding angles on extrusion-shearing-expansion(ESE) process of AZ31 magnesium alloy thin-walled tubes,the effects of different expanding angles on microstructures and mechanical properties of AZ31 magnesium alloy during extrusion-shear-expansion process have been investigated by optical microscope(OM),scanning electron microscope (SEM),X-ray diffractometer(XRD).Three expanding angles 130°,140°,150° have been used.The forming loads varying with expanding ratios,and equivalent strains at various expanding angles have been simulated by Deform-3D software.The research results show that the qualities and mechanical properties of the formed tube are satisfactory, and extrusion-shearing-expanding process can refine the grain of AZ31 magnesium alloy thin-walled tubes.The grain sizes decrease with the decrease of expanding angles.When the expanding angle is 140°,the comprehensive mechanical properties are best,and yield strength is 122.3MPa,the tensile strength 288.6MPa,the elongation 15.2%, the texture intense is optimized due to the DRX.The deflections of basal plane for most grains are obvious relative to the extrusion direction(ED).