Influence of laser power on the surfacing microstructures and microhardness properties of Ti-6Al-4V-Cualloys using the ytterbium fiber laser

Laser Metal Deposition (LMD) is a route that involves the spraying of metallic powders onto a substrate with the application of beam of light. The deposition of titanium alloy (Ti-6Al-4V) with five weight percent (5 wt%) of copper (Cu) has been explored and characterized through the developing microstructures and microhardness. A constant scanning speed of 0.3 m/min and laser powers varied between 400 W and 1600 W were used for the process parameters. The Widmanstatten structures were even at low laser powers and later increased in their coarseness and propagate further as the laser power increases; and the occurrence can be attributed to the further increase in the heat input from the top of the clad to the substrate and the slow cooling rate within the cladded zone of the composites.A typical sample D4 deposited with a laser power of 1000 W exhibits the highest hardness value of 541 ± 88 HV_0.5 while sample D2 deposited at a laser power of 600 W depicts the lowest hardness value of 448 ± 58 HV_0.5. The properties of the Ti-6Al-4V-Cu alloys have been improved and can be recommended for marine application.