Laser Surface Coating of Metal Matrix Composite on Ti6Al4V Alloy

Laser surface coating of Mo, WC and Mo-WC powders on the surface of Ti6Al4V alloys using a 2kW Nd-YAG laser was performed. The dilution effect, microstructure, microhardness and wear resistance of the fabricated MMC coating were investigated. With a constant thickness of pre-placed powder, the dilution levels of the alloyed layers were found to be increased with the incident laser power. The fabricated MMC layer was metallurgically bonded to the Ti6Al4V substrate. The microhardness of the fabricated surface layer was found to be inversely proportional to the dilution level. The EDAX and XRD spectra results show that new intermetallic compounds and alloy phases were formed in the laser fabricated layer. With increasing weight percentage content of WC particles in the Mo-WC pre-pasted powder, the microhardness and sliding wear resistance of the laser surface coating were increased by 87% and 150 times respectively as compared with the Ti6Al4V alloy.