Advanced coating: Laser metal deposition of aluminium powder on Titanium substrate

Laser Metal Deposition (LMD) is an additive manufacturing technique, which can be used to produce solid components from a Computer Aided Design (CAD) model. The LMD process makes use of feeding powder, which is supported by the shielding gas, into the melt pool that is produced by sharply focused collimated laser beam on the substrate. This study employs aluminium powder in its molten state on titanium substrate through the LMD process. The aluminium powder was deposited at varying laser scanning speeds while the laser power and gas flow rate were kept constant. The presence of alpha phase grains were observed in the microstructures of samples at a lower scanning speed and the beta phase grains at a higher laser scanning speed. It was found that the geometrical properties of the deposits, that is; the width, height and the Heat Affected Zone (HAZ) of each sample decreased as the scan speed increases resulting from the laser-material interaction. The microhardness and the corrosion rates of each sample increased as the laser scanning speed increases.