Effects of particle size and content of cladding powder on in situ synthesized WC-reinforced Ni-based cladding layers

Laser cladding technology can obtain a cladding layer with good metallurgical bonding with the substrate and excellent performance. In situ growth of hard phase can effectively solve the problem of uneven distribution of reinforcements directly doped with hard particles. In this paper, 45# steel was adopted as the matrix material, WO3, B4C, Al, and Ni60 powder were used to prepare laser cladding and in situ synthesized WC (Tungsten Carbide) hard phase reinforced Ni-based cladding layers. The effects of different laser cladding parameters, powder particle size, hard phase content on the microstructures and electrochemical properties of in situ synthesized WC hard phase reinforced Ni-based cladding layer were analyzed. The results revealed that when the (WO3 + B4C + Al) mixed powder content was 25%, the bulk particles of WC phase in the cladding layer were most uniformly distributed in the cladding layer, which enhances the mechanical properties of the cladding layer. When the B4C particle size was 5 mu m, the microhardness of the cladding layer was significantly higher than other cladding layers, and the enhancement mechanism of hardness by B4C is due to the Orowan strengthening caused by too small particle size of B4C.