Microstructure and mechanical properties of AZ91D magnesium alloy prepared by compound extrusion

Based on conventional extrusion and equal channel angular extrusion (ECAE), a new severe plastic deformation (SPD) method called compound extrusion is developed to fabricate fine-grained AZ91D magnesium alloys. The fine grain size of 6 μm is obtained as the accumulated strain increased to 9.146. The AZ91D alloy treated by compound extrusion exhibits good mechanical properties, with a yield strength of 202.2 MPa, a tensile strength of 323.1 MPa and an elongation to fracture of 14.8%. The good mechanical properties of AZ91D alloy treated by compound extrusion are due to grain refinement and to the homogeneous distribution of intermetallic particles. The success in development of compound extrusion proves that compound extrusion can offer a good opportunity for the development of good mechanical properties of as-cast magnesium alloys.