Microstructure and cavitation behavior of laser-cladded GH4169 coatings with various WC additions

To improve the cavitation erosion resistance of submarine propeller blades, GH4169 composite coatings with tungsten carbide (WC) contents ranging from 0% to 60% were fabricated on the 316L substrate via laser cladding. Scanning electron microscopy and ultrasonic cavitation tests were adopted to systematically investigate the effects of WC content on the microstructure evolution and cavitation behavior of the coatings. The results show that the addition of WC significantly optimizes the microstructure and comprehensive properties of the coatings. The coating with 20% WC exhibits the best cavitation erosion resistance, featuring the minimum mass loss, shallow and uniformly distributed erosion pits, as well as the lowest pit damage area ratio of only 1.53%. Mechanism analysis reveals that well-dispersed WC particles can effectively resist the impact of microjets and inhibit crack propagation. Excessive WC addition leads to particle agglomeration and weakened interfacial bonding, which in turn aggravates coating damage.