Microstructure and wear properties of laser surface-cladded Mo-WC MMC on AA6061 aluminum alloy

The creation of a wear-resistant surface of metal matrix composite on AA606 1 aluminum alloy by laser surface melting of pre-pasted Mo-WC powder was su ccessfully achieved using a 2-kW CW Nd-YAG laser. A high-quality coating wi thout porosity or cracking was obtained. Excellent bonding between the coat ing and the aluminum alloy substrate was ensured by the strong metallurgica l interface. Different ratios of Mo and WC powders were investigated. The c hemical composition, microstructure and surface morphology of the clad laye r were analyzed using scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDX) and X-ray diffractometry (XRD). The surface hardn ess of the Al specimens clad with Mo/WC is increased seven-fold. The sample s have been characterized with abrasive pin-on-disc wear tests. The test re sults show that the composite coating with a WC hard phase has improved abr asive wear resistance when compared with the as-received A] substrate. The wear mechanism of the specimens is discussed based on microscopic observati on of the worn surface. (C) 2001 Elsevier Science B.V. All rights reserved.