A comparative study on microstructure evolution and wear resistance of different-sized tungsten carbide modified Fe-based laser cladding coatings

Abstract

In the present study, Fe-based laser cladding coatings with different-sized WC particles were fabricated on the surface of 16Mn steel, aiming at exploring the effect of different-sized WC addition on microstructure evolutions, microhardness and wear resistance of composite coatings. Results showed that for composite coatings, a change in particle size of WC had a negligible effect on phase constituents, but it was found effective in influencing the microstructure, microhardness, and wear resistance. The main phases of composite coatings were mainly composed of α-Fe, γ-(Fe, Ni), WC and M23C6 (M: Cr, W, Fe). Small-sized WC played a positive effect in forming homogeneous and finer microstructure in composite coating, while the effect of large-sized WC was the opposite. The microstructure of small-sized WC-contained coating only contained dendritic α-Fe matrix and inter-dendritic composite carbides of WC + M23C6. The microstructure of large-sized WC-contained coating in the centre and edges was entirely different. The microstructure in the centre consisted of dendritic α-Fe matrix and inter-dendritic fine lamellar eutectics of α-Fe + M23C6. The microstructure in the edges consisted of dendritic α-Fe matrix and inter-dendritic carbides of M23C6. Besides, the strengthening effect of small-sized WC was much better than that of large-sized WC.