Mg-Gd-Y-Zn-Zr Mg alloys show excellent performance in high-end manufacturing due to its strength, hardness and corrosion resistance. However, the hot deformation and dynamic recrystallization (DRX) behaviors of Mg-13.5Gd-3.2Y-2.3Zn-0.5Zr were not studied. For this article, hot compression behavior of homogenized high rare-earth (RE) content Mg-13.5Gd-3.2Y-2.3Zn-0.5Zr (wt%) alloy was investigated by using the Gleeble-3500D thermo-simulation test machine under the temperature of 350–500 °C and the strain rate of 0.001–1 s⁻¹. It was found that the high flow stress corresponded to the low temperature and high strain rate, which showed DRX steady state curve during the hot compression. The hot deformation average activation was 263.17 kJ/mol, which was obtained by the analysis of the hyperbolic constitutive equation and the Zener-Hollomon parameter. From observation of the microstructure, it was found that kink deformation of long period stacking ordered (LPSO) phase was one of the important coordination mechanisms of hot deformation at low temperature. The processing map with the strain of 0.5 was established under the basis of dynamic material model (DMM); it described two high power dissipation domains: one appearing in the temperature range of 370–440 °C and the strain rate range of 0.001–0.006 s⁻¹, the other appearing in the temperature range of 465–500 °C and strain rate range of 0.001–0.05 s⁻¹, in which dynamic recrystallization (DRX) mainly ocurred. The highest degree of DRX was 18% from the observation of the metallographic.

Magnesium (Mg) alloys attract considerable attention in the fields of aerospace, defense technology, and automobile production, owing to the advantages of their low density, their highly specific strength/stiffness, and their good damping and electromagnetic shielding performance. However, low strength and poor ductility limit further application. Severe plastic deformation is considered the most promising means of producing ultrafine-grained Mg alloys and improving their mechanical properties. To this end, high-pressure torsion (HPT) is one of the most effective techniques. This article outlines the microstructure, texture, and mechanical properties of Mg alloys processed using HPT. The effects of deformation parameters, such as processing temperature, turns, applied pressure, and rotation speed, on the grain refinement and secondary phases are discussed. Textural evolution is detailed in light of both intrinsic and extrinsic factors, such as cumulative strain and the composition of the alloy elements. The subsequent enhancement of mechanical properties and mechanisms, and the significant contribution of the HPT process to strength are further reviewed. Given the advantages of HPT for grain refinement and structural modification, researchers have proposed several novel processes to extend the industrial application of these alloys.