Tribological performance enhancement of laser-cladded In718/WC composite coatings via optimized WC reinforcement conten

Nickel-based superalloys are widely employed in critical service scenarios of mechanical engineering, owing to their excellent creep strength and superior high-temperature corrosion resistance. However, their intrinsically low microhardness easily causes abnormal wear and fatigue cracking, threatening service safety. Herein, WC-reinforced In718 composite coatings were laser-cladded on In718 substrates, and their tribological enhancement mechanisms were systematically elucidated. Localized critical melting occurs at WC particle peripheries, promoting complex multiphase metallurgical microstructures that enhance interfacial bonding strength. The coatings consist of face-centered cubic γ-Ni, (Ni, Cr) and (Ni, Fe) solid solutions, with in-situ precipitated hard phases and precipitation-strengthening phases. Due to the synergistic strengthening from WC dispersion, grain refinement, and multiphase in-situ precipitation, the coatings exhibit 49.3%–70.7% higher microhardness, stable 0.66–0.72 coefficient of friction, and 38.2%–70.4% lower wear mass loss. In-situ precipitated Fe3W3C hard phases and WO3 oxides induced by frictional heat further enhance wear resistance. Dominant wear mechanisms include abrasive wear, adhesive wear, and fatigue wear, with oxidative wear increasing remarkably under high loads. Progressively enhanced dispersion and grain refinement strengthening from higher WC content, coupled with in-situ precipitated hard phases, synergistically improve tribological performance. This study provides a new technical reference for fabricating high-tribological-performance In718/WC coatings, addressing the poor wear resistance of nickel-based superalloys.