Effect of laser power on material efficiency, layer height and width of laser metal deposited Ti6Al4V

This paper reports the effect of laser power on the optimum utilization of the powder material, the layer height and the width of the laser Metal Deposited Ti6Al4V. The Ti6Al4V powder was deposited on Ti6Al4V substrate using an Nd: YAG laser of varying power between 0.4 kW and 3 kW. The other processing parameters; scanning speed, powder flow rate and gas flow rate were kept constant throughout the experiment. The effect of these laser powers on the layer height and width, the material efficiency and the metallurgical integrity were investigated. The weight of the substrate was taken before and after the deposition. Wire brush was used to remove the unmelted powder particles from the surface of the deposit and cleaned with acetone before it was re-weighed. The height of the deposit above the substrate and width of the layers were measured using the Vernier Caliper. The material efficiency was then determined. Metallurgical samples were prepared for macro and microstructural extermination to observe the soundness of the deposited tracks. All the deposited tracks are metallurgically sound except the sample produced at 400 w with poor bonding to the substrate. It was found that the width of the layer increases with increase in the laser power while the height increases initially then decreases as the laser power increases with the maximum increase occurring at the laser power of 1.6 kW. The powder efficiency also increases with the increase in the laser power with the optimum value at a laser power of 1.6 kW.