Abstract：With Ni-Cr-Fe alloy powder and Al coated nickel powder as coating material, cladding alloy coating
was prepared by laser cladding on AZ91D alloy. The microstructure and properties of the coating were tested. The
results show that the comprehensive properties of the coating are the best when the content of Ni-Cr-Fe alloy powder
is 30% . The thickness of cladding layer is 827 μm,the dilution ratio is 22.62%, the coating area is 1 000～3 000
μm and the hardness is 758~819HV0.5. In the SEM microstructure of the cladding coating, the petal structure composed
of Ni, Cr and Al is the most; XRD analysis shows that the phase is mainly composed of γ-Ni，α-Cr，FeNi3，
Fe3Ni2，Cr2Ni3 and (Cr，Fe)7Al. The average friction coefficient is 0.28 and the wear amount is about 2.7 mg. In the
fracture toughness test, there is no expansion crack at the indentation, the indentation thickness is relatively
uniform, the shape is clear and visible, and the symmetry is good, showing anisotropic fracture characteristics in
the direction perpendicular to the interface. The results of high temperature oxidation test shows that the weight
gain rate of the coating is slowing down, which indicats that the coating improves the possibility of protecting
AZ91D magnesium alloy from high temperature.
2021, Vol. 31 
