Effect of Multidirectional Forging on the Microstructure Evolution and Mechanical Properties of Mg-2Sn-2Zn-0.7Mn-0.5Ca Alloys

The Mg-2Sn-2Zn-0.7Mn-0.5Ca (wt.%) alloy was employed to investigate the effect of forging passes on both microstructural and mechanical properties as well as the mechanism of multidirectional forging (MDF). The results show that with the increase of MDF passes, the second phase is fragmented and dispersed. At the same time, the alloy's microstructure exhibits necklace-like microstructures with different thicknesses due to the generation of recrystallized grains. After the alloys are deformed by the first forging pass (MDF-1) and the third forging pass (MDF-3), both the strength and plasticity tend to increase. The strength of MDF-3 passes is the highest (230 MPa), while the elongation is improved in the fifth forging pass (MDF-5) deformed alloy with a concomitant decrease in tensile strength by 11 MPa. This phenomenon occurred because, after the alloy undergoes MDF-5 deformation, the texture changes from a typical basal texture to a bimodal texture. In other words, following MDF treatment, grain refinement and texture weakening together affect the mechanical properties of the alloys.