Analysis of WC Distribution and Microstructure Evolution in a WC/17-4ph Composite Coating Prepared by High Speed Laser Cladding (HSLC)

To prepare a high quality Fe-based ceramic composite coating, 17-4ph+30% WC alloy powder was clad onto a 17-4ph stainless steel substrate by high speed laser cladding (HSLC) and a metal matrix composite (MMC) clad without cracks and pores was achieved. The WC particle distribution, microstructure formation and evolution mechanism of the MMC laser clad were studied in detail. The results show that the phase composition of the MMC laser clad mainly includes gamma-Fe, W2C, WC, Ni3Fe, Cr23C6, etc. The WC particles in the MMC laser clad show a good metallurgical bonding with the 17-4ph substrate, the dilution rate of the clad is low and the higher heat input causes more WC particles to melt and decompose, generating more hard strengthening phases. The grain refinement strengthening, solid solution strengthening and second phase strengthening are more prominent, which provides a scientific basis for optimizing the preparation of high quality Fe-based ceramic composite coatings.