Enhanced mechanical properties of Mg–Gd–Y–Zr casting via friction stir processing

Mg–10Gd–3Y–0.5Zr casting was subjected to friction stir processing (FSP) at a tool rotation rate of 800 rpm and a traverse speed of 50 mm/min. FSP resulted in the fundamental dissolution of the coarse network-like β-Mg5(Gd,Y) phase and remarkable grain refinement (∼6.1 μm), thereby significantly improving the strength and ductility of the casting. Post-FSP aging resulted in the precipitation of fine β′′ and β′ particles in a fine-grained magnesium matrix, producing an ultimate tensile strength of 439 MPa and a yield strength of 330 MPa. FSP combined with aging is a simple and effective approach to enhancing the mechanical properties of Mg–Gd–Y–Zr casting.

Research highlights▶ Friction stir processing (FSP) dissolved the coarse β-Mg5(Gd,Y) phase and refined the grains. ▶ Post-FSP aging resulted in the precipitation of fine β′′ and β′ particles. ▶ FSP enhanced the mechanical properties of Mg–Gd–Y–Zr casting significantly.