LASER CLADDING OF MG-AL ALLOYS

Among rapid solidification processing methods, laser cladding is a unique and promising technique which can be used to increase the corrosion resistance of materials. This paper describes the improvement of the laser-cladding process for magnesium-based alloys and an investigation of the effect of the laser-cladding technique upon the microstructure and the corrosion resistance of magnesium-based alloys. The cladding apparatus and techniques have been adapted for magnesium cladding to overcome the oxidation and high vapour pressure-related problems. Laser-clad Mg27Al73, Mg53Al47, and Mg72Al28 have been obtained. Eutectic phases were observed in the two magnesium-rich alloys and in the interface of the aluminium-rich alloy. Polycrystalline structure was formed in Mg27Al73. Laser-clad Mg27Al73 was found to be superior to laser-clad Mg-5 wt % Zr, Mg-2 wt % Zr, cast AZ91 B and cast magnesium in corrosion properties.