INFLUENCE OF ZrB2 ADDITION ON MICROSTRUCTURAL DEVELOPMENT AND MICROHARDNESS OF Ti-SiC CLAD COATINGS ON Ti6Al4V SUBSTRATE

Abstract

The microstructural features and microhardness of ZrB2-reinforced Ti-SiC coatings on Ti-6Al-4V substrate were studied. The deposition of these coatings was achieved via laser cladding technique. A 4.0[Formula: see text]kW fiber-delivered Nd: YAG laser was used to deposit the coatings on the titanium substrate at a laser power of 700[Formula: see text]W and a laser scan speed of 0.8[Formula: see text]m/min. An initial Ti-SiC coating was deposited with no ZrB2 addition followed by deposition of two other coatings with the incorporation of ZrB2 powder at 5 and 10[Formula: see text]wt.%. The coatings were examined using scanning electron microscope (SEM) coupled with energy dispersive spectroscopy. SEM images of Ti-SiC-ZrB2 coatings revealed good metallurgical bond between the coatings and the substrate and also a significant increment in dendritic formation and inter-dendritic eutectics during solidification within the [Formula: see text]-Ti matrix, exhibiting the presence of newly formed phases as the weight percentage of ZrB2 increased. Back-scattered electron images also showed the dissolution effect of SiC particles, as the particle–matrix bond strength is influenced by ZrB2 addition. Furthermore, the microhardness of the Ti-SiC coating was enhanced with increasing ZrB2 weight percentage. X-ray diffraction analysis revealed dominant compounds formed during laser material processing. This study deepens the knowledge of possible microstructural features associated with Ti-SiC-ZrB2 cermet coatings.