Effect of scanning speed on microstructure and properties of TiC/Ni60 composite coatings on Ti6Al4V alloy by laser cladding

Abstract

The coatings are fabricated with 90 wt% TiC+10 wt% Ni60 powders on Ti6Al4V alloy by laser cladding. The effect of scanning speed on the microstructure and wear behaviors of the coatings is investigated. The results indicate that the clad height decreases with increasing the scanning speed. The clad width and clad depth decrease with increasing the scanning speed. Large-size particles are randomly distributed in the coatings, which are considered to be TiC particles. The microstructure in the coatings changes with the scanning speed by laser cladding. A large number of TiC particles and phases in network structure are observed in the coatings at low scanning speed. The rod and granular TiC particles are exhibited in the coatings at high scanning speed. Some TiC particles are dissolved in the molten pool during laser irradiation heating and then dissolving Ti and C atoms leads to the precipitation of TiC phase during solidification. It is found that the hardness decreases with increasing the scanning speed, whereas the weight loss of the coatings increases. It therefore enhances the wear resistance properties due to the effect of TiC particles.