MICROSTRUCTURE AND WEAR PROPERTIES OF COMPOSITE COATINGS PRODUCED BY LASER CLADDING OF Ti-6Al-4V WITH GRAPHITE AND SILICON MIXED POWDERS

Composite coatings are fabricated by laser cladding of titanium alloy Ti-6Al-4V with graphite and silicon mixed powders. X-ray diffraction (XRD) and energy dispersive spectroscopy (EDS) indicate that the coatings mainly consist of pre-eutectic TiC and eutectic Ti5Si3 compounds. Test results show that the coatings exhibit a higher microhardness and a lower friction coefficient compared with the as-received sample. EPMA micrographs show that the compounds' morphology in the top zone of the coatings is different from that in the transitional zone.