Solute Redistribution Assisted Dual‐Gradient Structure With Superior Strength–Ductility Balance in Mg–Zn–Gd Alloy
Abstract
Heterogeneous structures have demonstrated great potential for overcoming the long‐standing strength–ductility trade‐off in metallic materials. In this study, a novel dual‐gradient structure, characterized by gradients in both grain size and precipitate distribution, was successfully constructed in an Mg–2Zn–0.8Gd (wt%) alloy sheet via sliding friction treatment (SFT). Severe plastic deformation arouses pronounced precipitate redistribution within the SFTed region, which can be divided into three successive and interrelated processes, namely mechanically induced precipitate dissolution, solute diffusion, and reprecipitation. The SFTed Mg–2Zn–0.8Gd (wt%) alloy exhibits a yield strength of 242 MPa, an ultimate tensile strength of 330 MPa, and a tensile elongation of 18.1%. Compared with the homogeneous counterpart, the gradient‐structured alloy exhibits a significantly alleviated strength–ductility competitive relationship. The improved mechanical performance is mainly attributed to the synergistic contributions of grain refinement, dislocation strengthening, precipitate strengthening, and hetero‐deformation‐induced (HDI) strengthening. These findings provide new insights into the microstructural design of heterostructured Mg alloys and offer an effective strategy for tailoring their mechanical properties.