Laser Cladding of Commercially Pure Titanium by Tungsten Carbide-Cobalt Composite Coating

Titanium has been a widely used alloy in industrial applications due to its excellent specific strength, high corrosion resistance, etc. Despite these superior characteristics, poor surface properties such as low hardness limit titanium applications. Many studies were conducted on surface properties improvement on titanium and its alloys. Laser alloying is one of the newest methods in order to enhance the surface properties of the parts. In this study, using a fiber laser beam as an energy source, titanium substrate was subjected to surface melting and surface alloying by introducing tungsten carbide (WC) particles. Two critical parameters, including laser power and scanning speed, were optimized, and defects were successfully eliminated. The influence of process parameters on defects, size, and shape of the melt pool and HAZ was discussed. Various microstructural characterizations were implemented to study the possible phase transformations in the examined system. Microhardness results show that on the surface of alloyed samples, the microhardness significantly increases and reaches 1900 Hv, which gradually moves towards the substrate and reaches 150 Hv in the substrate.