Effect of interface geometry on microstructural evolution and wear resistance of laser-cladding Ni-based composite coatings for shaft components

Abstract

To improve the wear resistance and reliability of laser cladding composite coatings for shaft components, this study proposes a laser cladding strategy based on engineered interface geometry. Continuous helical V- and U-shaped grooves of 0.3 and 0.6 mm depth were machined on the shaft surface prior to cladding to regulate heat transfer, melt flow, and solidification behavior. Ni-based composite coatings with in-situ ceramic phases were fabricated on the grooved surfaces, and the effects of groove geometry and depth on the microstructure and wear resistance were systematically investigated. The results show that the grooves reduced heat dissipation and promoted melt flow, thereby facilitating Ti and C diffusion and the in-situ formation and homogeneous dispersion of ceramic phases. The 0.3-mm-deep U-shaped grooves effectively reduced porosity, while the 0.6-mm-deep U-shaped grooves promoted a more homogeneous ceramic-phase distribution. Compared with the ungrooved coating, the coating with 0.6-mm-deep U-shaped grooves exhibited 7.7% higher microhardness and 44.9% lower wear volume. The improved wear resistance was ascribed to the more homogeneous ceramic-phase distribution and the mechanical support provided by the substrate grooves under the applied load. This study provides a practical interface-engineering strategy for improving the microstructure and wear performance of laser cladding ceramic-reinforced composite coatings.