Role of WC reinforcement on microstructure, hardness and corrosion resistance on laser NiCoCr-cladded EN8 steel

Laser cladding was employed to develop NiCoCr medium-entropy alloy (MEA) coatings reinforced with 20, 30, and 40 wt.% WC on EN8 steel substrates. Optimized process parameters produced coatings with strong metallurgical bonding and a minimal heat-affected zone. Microstructural analyses (XRD, OM, and SEM) revealed rapid solidification-induced cellular, columnar, and equiaxed grains, while WC particles facilitated heterogeneous nucleation and grain refinement. The addition of WC significantly enhanced microhardness, reaching a maximum of 506 ± 18.6 HV (∼80% higher than the substrate). Among the WC-reinforced coatings, the 20 wt.% WC coating exhibited superior corrosion resistance compared with the 30 and 40 wt.% WC coatings. Although friction increased with higher WC content, the tribological response was significantly influenced, which is likely associated with effective load sharing and reduced plastic deformation. Overall, the study demonstrates that WC-reinforced NiCoCr MEA coatings offer a promising balance of mechanical strength, wear resistance, and corrosion performance for advanced surface engineering applications.