Laser Gas Alloying of Ti-6Al-4V

The present study concerns in-depth analysis of the alloyed zone formed by laser gas alloying of Ti-6Al-4V by melting the surface using a continuous wave Diode laser using nitrogen shroud. A detailed structure-property-process parameters correlation has been undertaken to optimize the process parameters. The microstructure of the alloyed zone consists of dispersion of titanium nitrides in α-Ti matrix. The morphology and mass fraction of titanium nitride was found to vary with laser parameters (applied power and gas flow rate). Residual stress on the surface nitrided zone was found to vary with laser parameters, application of high power and low gas flow rate was found to be essential in reducing residual tensile stress. The microhardness and corrosion property of the alloyed zone were improved significantly as compared to as-received Ti-6Al-4V substrate.