Effect of La₂O₃ Content on Cracking Sensitivity and Properties of Laser Cladding Ni60 Cladding Layer

In order to study the effect of rare earth La₂O₃ on the cracking sensitivity and properties of laser cladding nickel-based alloy, stainless steel 316L cladding Ni60 alloy powder was taken as the research object, the cracking sensitivity, forming coefficient, dilution rate and microhardness of the cladding layer of 316L surface by cladding Ni60+La₂O₃ mixed powder were investigated by tinted flaw detection, industrial microscope and microhardness tester when the mass fraction of La₂O₃ was 0, 1wt%, 2wt%, 3wt%, 4wt%, 5wt% and 6wt%. The results show that when the content of La₂O₃ is 5wt%, the surface crack density of the cladding layer is the smallest, which significantly reduces the cracking sensitivity of cladding layer and inhibits the generation of cracks. At this time, the forming coefficient of cladding layer reaches the maximum of 51.57, and the dilution rate of cladding layer reaches the minimum of 13.2%. The average microhardness of the single cladding layer is 658 HV0.2, 2.6 times of the average microhardness of the substrate. Compared with without the addition of La₂O₃, the average microhardness of the cladding layer is increased by 15%, which effectively improves the microhardness of the cladding layer and obtains the best quality cladding layer. This study provides a reference for the wider industrial application of laser cladding nickel-based alloys.