IMROVEMENT OF SURFACE PROPERTIES OF ALUMINIUM ALLOY BY LASER CLADDING USING POWDERS

Abstract

The synthesis of a wear-resistant surface of metal matrix composite (MMC) on AA6063 aluminium alloy by laser surface melting of pre-pasted Mo-WC powder was successfully achieved using a 10-kW continuous wave CO2 laser. A high quality .coating without porosity or cracking was obtained. Good bonding between the coating and the aluminium alloy substrate was ensured by the strong metallurgical interface. Different ratios of Mo and WC powders were investigated. The microstructure and surface morphology of the clad layer were analyzed using X-ray difractometry (XRD) and scanning electron microscopy (SEM). The surface hardness of the specimens clad with 30/70 Mo-WC powders is increased six-fold. The test results show that the composite coating with a WC hard phase has improved abrasive wear and corrosion resistance when compared with the aluminium alloy but not suitable for the long run application as it shows cracking at the interface. The erosion, abrasion and corrosion mechanisms of the specimen