Insights into microstructure characteristics along with wear behavior of AlSi₁₂ coating on Mg-Gd-Y-Zn-Zr alloy through laser cladding

The paper fabricates AlSi₁₂ coating on Mg-Gd-Y-Zn-Zr alloy surface through optimizing laser cladding parameters to enhance the surface properties, including laser power and scanning velocity. The microstructure characteristic and wear resistance of the cladding layers were also systematically investigated. The high energy density from laser effectively melted AlSi₁₂ powder and the Al, Si, Mg, Gd, Y atoms diffused to form a molten pool, which resulted in the formation of gradient composition at the interface. The results indicated the cladding layer achieved excellent metallurgical bonding with Mg-Gd-Y-Zn-Zr substrate. In addition, the Mg₂Si, Mg₂Al₃ and Mg₁₇Al₁₂ phase precipitated within cladding layer, and eutectic (Mg, Zn)₃(Gd, Y) phase formed at transition zone. The average hardness of cladding layer reached 160 HV, representing 74 % increase compared to the substrate. Friction and wear tests show that AlSi₁₂ coating at 1440 W demonstrates a lower wear volume compared with substrate, and the friction coefficient stably remains at 0.397 and wear mechanism is mainly controlled by adhesive wear.