Study on laser cladding system of the high-entropy alloy layer on the AZ91D magnesium

A new type of composite layer material system, Al4Ni/Al2CrCuFeNi2Ti high-entropy alloy, was designed. The Al4Ni transition layer was prepared on the surface of an AZ91D magnesium alloy by laser cladding, which solves the problem of excessive melting point difference between the magnesium alloy and the high-entropy alloy. The Al4Ni/Al2CrCuFeNi2Ti high-entropy alloy composite layer with good surface formation was successfully prepared on the AZ91D magnesium matrix. Optical microscope, scanning electron microscope, and x-ray diffraction were used to characterize the microstructure and properties of the composite layer. It showed that the high-entropy alloy layer was mainly composed of simple BCC and FCC solid solution phases. The Al2CrCuFeNi2Ti high-entropy alloy layer, the Al4Ni layer, and the AZ91D magnesium matrix have excellent metallurgical bonds. The hardness of the high-entropy alloy layer was about 12 times that of the AZ91D magnesium alloy. The corrosion resistance of the high-entropy alloy layer in 3.5 wt. % NaCl was also improved.