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.

Microstructure and Wear Behavior of Ti-xFe-SiC In Situ Composite Ceramic Coatings on TC4 Substrate from Laser Cladding

“…Due to the extremely high hardness, high wear resistance, low density, and high designability, ceramic particles have often been added to metal to improve the mechanical strength and wear resistance of the laser cladding coating [ 11 ]. Ti-SiC systems are very prone to in situ reactions during the laser cladding process, thereby generating a TiC ceramic phase with high hardness and wear resistance, a Ti 3 SiC 2 phase with self-lubrication, and a Ti 5 Si 3 phase with good high-temperature resistance [ 12 , 13 , 14 ]. However, the addition of SiC particles is limited to less than 50%.…”