Microstructure and mechanical properties synergistically enhanced via heat treatment modification of the as-extruded Mg-1.5Al-0.5Zn-0.2Y-0.2Ca alloy

The Mg-1.5Al-0.5Zn-0.2Y-0.2Ca alloy was fabricated via microalloying with Y and Ca elements. Subsequent to extrusion deformation and heat treatment, a comparative analysis of the microstructure, texture strength, mechanical properties, and strengthening mechanisms was performed. The results revealed that the heat-treated alloy showed an enhanced degree of dynamic recrystallization (DRX) compared to the as-extruded alloy, this was accompanied by the dissolution of Al and Y elements and the precipitation of Al4Ca nanophases during the heat treatment process. Moreover, the UnDRXed regions displayed a pronounced basal texture, which was attributed to the larger grain size in these areas, resulting in a more distinct orientation distribution. Analysis showed that the prismatic and pyramidal slip systems have higher Schmid factors, increasing the propensity for non-basal slip. In addition, the strength of the alloy enhanced by dislocation strengthening and solid solution strengthening. As a result, the Mg-1.5Al-0.5Zn-0.2Y-0.2Ca alloy demonstrated an excellent balance between strength and plasticity.