Abstract
Improvements in manufacturing processes are required in light of recent discoveries in order to produce materials that perform better in their intended application. Composite materials are new class of material owing to their superior mechanical and corrosion properties. As such titanium matrix composite have received more attention with one such composite being the TiC/Ti6Al4V-ELI composite. This study focused on optimization of a deposition of TiC/Ti6Al4V-ELI metal composite through the laser metal deposition technique. The main parameter varied was the powder feed rate, carried through by argon gas to the three way nozzle. The other critical parameters were kept constant, which include laser power, working distance, scanning speed, carrier and shielding gas flows. The produced samples were classified into three groups of single tracks, single layer, and cube. For analysis of samples, standard metallographic practices were followed. The results showed that the relationship between feed rate is a function of process parameter and microstructure. Feed rates of 0.3 rpm TiC / 7.5 rpm Ti6Al4V-ELI 0.2 rpm TiC / 5.0 rpm Ti6Al4V-ELI and 0.1 rpm TiC / 2.5 rpm Ti6Al4V-ELI produced the finest composite samples (TiC/Ti6Al4V-ELI), which showed microstructure homogeneity. Microstructure analysis using SEM revealed that dendrites structures tend to form at a powder feed rate of 0.4 rpm TiC / 7.5 rpm Ti6Al4V-ELI, 0.3 rpm TiC / 5.0 rpm Ti6Al4V-ELI and 0.2 rpm TiC / 2.5 rpm Ti6Al4V- ELI single layer samples developed grain coarsening, which was observed in the remelted zones. Samples were further analysed using Vickers microhardness test. The high hardness corresponded to TiC feed rates exceeding 0.3 rpm. Effects of grain coarsening were observed in the hardness plot which indicated a decline in hardness. The hardness plots revealed an increase in the clad zone, despite the fluctuations on the remelted zones.
The research study indicated that TiC/Ti6Al4V-ELI composite can be fabricated with laser metal deposition technique. The produced composites had a homogeneous microstructure and improved hardness behavior. These has provided the manufacturers and researchers with an alternative technique to produce composite materials.