Effects of Rare Earth Y<sub>2</sub>O<sub>3</sub> on the Microstructure and Wear Behaviors of Ti-6Al-4V Cladding with SiC

Abstract

This study elucidates the effect of the percentage of Y2O3 on the microstructure and tribological performance of Ti-6Al-4V clad by SiC and Ni powder, using gas tungsten-arc welding (GTAW). The microhardness of the clad layer was measured using a Vickers hardness tester. The microstructure of the clad layer was analyzed using a scanning electron microscope (SEM) and an electron probe micro-analyzer (EPMA). X-ray diffraction (XRD) was used to determine the constituent phases of the clad layer. A pin-on-disk rotating tribometer was used to evaluate the wear resistance of the substrate and the clad layer. According to the experimental results, TiC and TiSi2 reinforcing phases were formed in situ in the clad layer during cladding process. The microhardness of the clad layer was two to three times that of the substrate, and the wear loss of the clad layer was about 51.5%~14.7% of that of the substrate. The optimal amount of Y2O3 enhanced the formation of TiC and TiSi2 and thus improved the microhardness of the clad layer. However, an amount of Y2O3 that over a critical value reduced the formation of reinforcing phases and degraded the mechanical properties of the clad layer.