Research on Microstructure and Properties of Laser Cladded Al and Al-Si Coatings on AZ91D Magnesium Alloy

In order to improve the mechanical properties and corrosion resistance of the magnesium alloy surface, Al and Al-Si coatings were prepared on the surface of AZ91D Mg alloy by laser cladding technique, respectively. The experimental results reveal that the Al cladding layer contains α-Mg, Mg₁₇ Al₁₂ , Al₃ Mg₂ and Al phases. The Al-Si cladding layer also exhibits the presence of Mg₂ Si phases in addition to the previous four phases. Compared with that of the original samples, the microhardness of Al and Al-Si coatings increases to 215 HV and 220 HV, respectively, while their corrosion current densities decreases to 4.5 ×10^-4 and 7.466 ×10^-5A·cm², respectively, which indicates that the Al-Si coating has superior corrosion resistance. In addition, compared with the Al cladded layer, the Al-Si cladded layer also enhances the surface wear resistance of the sample.