Enhanced mechanical and corrosion properties of grain refined Mg-2.0Zn-0.5Zr-3.0Gd alloy

The microstructure, mechanical and corrosion properties of Mg-2.0Zn-0.5Zr-3.0Gd alloys in four different states (as-cast, solid solution, as-cast extrusion, and solid solution extrusion) were studied. Results show that the microstructure of alloys in different states is mainly composed of equiaxed cr-Mg matrix and (Mg, Zn)(3)Gd precipitates with different sizes. Among them, a small number of nano-sized (Mg, Zn)(3)Gd precipitates with a semi-coherent relationship with the matrix appeared in the solution-treated alloy. A large number of nano-elliptical Mg2Zn11 precipitates was found in the two extruded alloys. The temperature for dynamic crystallization of solid solution extruded alloy is higher than that of as-cast extruded alloy. The extruded solution-treated alloy exhibits the best mechanical properties and anticorrosive ability, which could be attributed to a more homogeneous microstructure, grain refinement, and the presence of nanometric secondary phase particles. Grain refined solution-treated alloy could have potential applications in metallic biomaterials.