Effect of Compound Extrusion on Microstructure and Mechanical Properties of Mg-4Sn-2Al-1Zn Alloy

Due to low strength and poor plasticity of magnesium alloys at room temperature, Mg-4Sn-2Al-1Zn alloys were extruded at 250. by compound extrusion process, and the microstructure evolution, texture and mechanical properties of the alloys after extrusion were studied. The results show that the grain size of Mg-4Sn-2Al-1Zn alloy can be refined from 45.2.m to 3.1.m by one-step compound extrusion, and the structure is uniform. The hardness and uniformity of the extruded alloy increase, and the yield strength, tensile strength and elongation after fracture are 204 MPa, 287 MPa and 21.0%, which are 140.0%, 91.3% and 156.1% higher than those of the homogeneous state, respectively. Dynamic recrystallization is the main mechanism of grain refinement. Grain refinement and basal plane texture enhancement after extrusion, and the uniform texture expansion in the extrusion direction improve the strength and plasticity of the alloy, and the Mg2Sn phase breakage further improves the mechanical properties of the alloy during extrusion. The above studies show that compound extrusion can effectively improve the comprehensive properties of magnesium alloys.