Abstract: The deformation mechanism, microstructure evolution, and precipitation behavior of a Mg-8.9Gd-1.8Y-0.5Zr-0.2Ag (wt.%) alloy multi-directionally forged at three different temperatures were investigated. As the forging temperature increases, the particle-stimulated nucleation (PSN) effect diminishes as the number of dynamic precipitates decreases, pyramidal slip is activated, grain boundary migration accelerates, and continuous dynamic recrystallization (CDRX) dominates. The microstructures varied greatly, although fine-grained structures were formed at all different forging temperatures. Competitive precipitation between dynamic precipitate growth, dislocation-induced precipitation, and homogeneous precipitation was observed after aging treatment. Among them, the medium temperature (748 K) forged and aged alloy exhibits the best mechanical performance, with an ultimate tensile strength of 436 MPa, and elongation of 16.3%. The calculation indicates that the mixed precipitation structure containing the $\beta^{\prime}$ precipitate band provides a 35% higher strengthening contribution than the typical homogeneously distributed precipitates. The formation of precipitation-free zones (PFZs) ensures that aging will not cause a dramatic decrease in ductility, which provides a reference for the industrial preparation of high-performance wrought Mg-Gd series alloys.

Key words: Mg-Gd-Y-Zr-Ag alloy, Multidirectional forging, Deformation mechanism, Aging behavior, high strength