Constitutive Description, Processing Maps, and Deformation Mechanisms of Extruded Mg‐3Nd‐1Gd‐1Zn‐0.5Zr (wt%) Alloy under High Temperature Tensile

In this article, the extruded Mg‐3Nd‐1Gd‐1Zn‐0.5Zr alloy is systematically investigated to elucidate its thermal deformation behavior, microstructural evolution, and dynamic recrystallization (DRX) mechanisms. High‐temperature experiments are conducted on a CMT high‐temperature tensile testing machine at temperatures ranging from 523 to 673 K and strain rates of 0.0001–0.1 s −1 . An Arrhenius‐type constitutive equation is developed from stress–strain curves, and processing maps are generated. The results show that deformation parameters strongly affect the high‐temperature plastic response. The alloy exhibits rheological instability at high strain rates, while favorable formability occurs only within a narrow temperature interval. Increasing temperature and decreasing strain rate enhances the power dissipation coefficient and suppress instability, defining the optimal hot‐working domain as 640–670 K and 0.0001–0.001 s −1 . Within this domain, CDRX (continuous DRX) occurs through subgrain boundary migration, forming uniform equiaxed grains and reducing dislocation density, also improving workability and stabilizing flow. At high temperatures and low strain rates, the fraction of recrystallized grains increases, dislocation density decreases, and rheological stress declines, promoting homogeneous microstructures. Microstructure analysis reveals that CDRX predominates at 673 K/0.001 s −1 , while discontinuous DRX dominates at 623 K/0.1 s −1 . These findings establish a direct link between processing conditions, DRX mechanisms, and macroscopic deformation behavior.