Laser cladding of carbon/magnesium metal matrix composites

Laser cladding of the Al-12Si alloy onto carbon short fibre reinforced AS41 magnesium alloy to improve the corrosion resistance was carried out successfully using the two-step method, first plasma spraying and then subsequently CO2-laser remelting. However, during the laser remelting, there was a tendency to void formation in both the clad layer and the substrate. This problem was overcome when an appropriate laser power coupled with a suitable accelerated scanning speed were used. In order to evaluate the corrosion resistance, polarisation measurements were carried out in neutral aqueous solutions of sodium chloride. A dramatic improvement in the corrosion resistance was observed in the laser clad surfaces compared to the untreated C/Mg composite.