Fabrication and tribological behavior of laser cladding Cu/Ti3SiC2 reinforced CoCrW matrix composite coatings on Inconel718 surface

Abstract

To satisfy the need for high wear resistance of Inconel718 alloy under harsh working conditions, laser cladding technique was adopted to fabricate the Cu/Ti3SiC2-CoCrW metal matrix composite coatings on that surface. The phase composition, microstructure, microhardness, surface energy, and tribological properties of the composite coatings were systematically analyzed by characterization methods such as XRD/ SEM/ EDS/ XPS and performance test methods such as high-temperature friction and wear test, and the wear mechanism at different temperatures was deeply discussed. The research results indicate that the microhardness of coatings is increased by 2.2–2.9 times compared to the substrate, which is mainly owing to the solid solution strengthening effect and the diffusely distributed hard reinforcing phases such as Cr7C3, WCx, and TiC. Regarding the wear resistance, the wear rate of coatings is significantly reduced by 1–2 orders of magnitude over the substrate. Among them, the Co-based coating adding 10 wt% Cu - 10 wt% Ti3SiC2 exhibited the lowest wear rates at room and high temperatures, which were 0.22 and 3.23 × 10−5 mm3/ N·m, respectively, with 98.22 % and 88.19 % reductions in comparison with the substrate. The low surface energy (27.94 mN/m) was one of the main reasons for the good tribological properties. When the friction environment changes from room temperature to 600 °C, the primary wear mechanism of coatings changes from abrasive and adhesive wear to oxidative wear.