Microstructure Evolution and Mechanical Properties of Mg-Gd-Y-Zn-Zr Alloy Deformed by Multi-Directional Forging with Decreasing Temperature

Abstract

The multi-directional forging process can achieve large plastic deformation, and has great application prospects in industrial production. The Mg-9.55Gd-3.28Y-1.77Zn-0.34Zr (wt%) alloy containing LPSO phase was deformed in different passes and then quenched immediately by the multi-directional forging process with decreasing temperature, and the microstructure and mechanical properties of the alloy were analyzed. It is found that as the number of deformation passes increases, the coarse grains decrease, and the dynamic recrystallization fraction increases. The dynamic recrystallization grains swallow the original grains, promote the continuous refinement of the grains, and greatly improve the uniformity of the microstructure. At the same time, the maximum texture intensity of the (0001) basal plane is significantly reduced, and the pole figure distribution is more dispersed, which is attributed to the random orientation of dynamic recrystallization. Due to the refinement of the microstructure and the weakening of the texture, the tensile strength and yield strength at room temperature increase significantly. After 3 passes of deformation, the alloy has the highest mechanical properties, with tensile strength, yield strength, and elongation reaching 317 MPa, 233 MPa, and 15%, respectively.