Strains prediction of new SPD process for AZ31 magnesium alloy fabrication

A plastic deformation method, which includes initial forward extrusion and bidirectional lateral extrusion process subsequently, has been used to fabricate the AZ31 magnesium (Mg) alloys. To research the grain refinement mechanism, strains and stress evolution, geometrical and finite element models for the structures of the die and billet have been constructed. Initial and boundary conditions have been exerted. The strain and stress predictions and influences of the severe plastic deformation (SPD) on the grain refinement of the microstructure and effective strain and stress have been researched. Microstructure observations have been carried out in different positions of formed rods. The results showed that original coarsen microstructure of about 400 μm can be refined to homogeneous microstructures with mean grain size of 20 μm at temperature 300°C as the accumulation strain was as high as 5. Increasing cumulative strain is the main reason for grain refinement during the process.