Effect of laser melting treatment on the structure and corrosion behaviour of aluminium and Al-Si alloys

In this paper, some samples of aluminium and Al-Si alloys were treated by a 2 kW CO2 laser, The microstructure of the samples was observed with both SEM and TEM, The anodic polarization behaviour of the Al and the Al-Ci alloy samples were measured in different corrosive media in order to evaluate the effect of Ia-Yr-melting treatment on the corrosion resistance of such alloys. Experimental results showed that laser melting treatment can not only make the aluminium alloy grains finer but also can increase the content of silicon to beyond the saturation content in alpha-Al. The corrosion resistance of the Al and the Al-Si alloys after laser treatment was found to increase in 10% H2SO4 and 10%HNO3 solutions. However. in 10%HCl and 5%NaCl solutions, the laser treatment did not have any significant effect on the corrosion behaviour of the Al and the Al-Si alloy.