Effect of W content on the wear resistance of Inconel 625/Y2O3 composite coatings by laser cladding

Abstract

In this study, tungsten (W) reinforced Inconel 625/Y2O3 composite coatings were fabricated on Inconel 625 substrates by laser cladding, and the effect of the content of W on the phase composition, microstructure, microhardness and wear resistance of the coatings were investigated. The addition of W relieves the residual stresses in the clad layer and has less effect on the deformation of the substrate. In addition, W can promote the precipitation of Laves phase while refining the grains. Excessive W content promotes the generation of more Laves phases in the coating and leads to W precipitation. It increases the microhardness of the coating, but causes microstructure unevenness. Y2O3 is enriched at the grain boundaries in the form of particles, which plays a role of pinning and inhibits the diffusion of the grain boundaries. When the content of W reaches 6wt%, the coating shows the best wear resistance with solid solution strengthening, fine grain strengthening and hard phase. When the content of W reaches 9wt%, the uneven distribution of the microstructure of the coating weakens the strengthening effect.