Study on microstructure and properties of thin tube of AZ31 magnesium alloy by extrusion technology

Magnesium alloys are widely used as medical applications due to the good mechanical properties, biodegradable and biocompatible advantages. The hydro-static extrusion forming technology of AZ31 magnesium alloy was studied, and AZ31 magnesium alloy thin wall tube with high toughness and ductility was developed. The results show that the optimal extrusion technological parameters are mold temperature of 300°C, billet temperature of 200°C, and extrusion ratio of 17-31.5.The optimal overall performance of the thin tube is obtained by hydrostatic extrusion and using superfine graphite powder and PVC molding powder as lubricating medium. The texture of extruded tube improves obviously, and the grain dimension of extruded tube change from 150 μm to below 7.0 μm. The compressive strength of AZ31 magnesium alloy increase from 210.5 MPa to 375.2 MPa by hydro-static extrusion.