Effects of Ni25 transitional layer on microstructural evolution and wear property of laser clad composite coating on H13 tool steel

Abstract Ni25 alloy was prepared as transitional layer on the damaged surface of H13 tool steel by laser cladding, and subsequently Fe104 alloy was cladded as strengthening layer to fabricate composite coating. The influences of Ni25 transitional layer on the phase compositions, microstructure, microhardness, and wear performance of Fe104 layer were systematically investigated. The results showed that the addition of Ni25 transitional layer effectively promoted the comprehensive performance and good metallurgical bonding of Fe104 layer. Moreover, large quantities of Ni element diffused into the Fe104 layer, resulting in the phase transformation from martensite to austenite, the decrease of carbides and the generation of intermetallic compounds, which arose the weakness of mechanical properties of coating to a certain extent. However, the composite coating exhibited higher average microhardness and better wear performance than the substrate, which accorded with the standard of industrial application. In conclusion, the influence mechanism of Ni-based transitional layer on the evolution of microstructure and wear performance was explained in detail.