Effects of Y2O3 additions on mechanically alloyed and sintered W—4 wt.% SiC composites

In this study, the effect of Y2O3 additions on the microstructural and the physical properties of W-SiC composites was investigated. Powder blends of W—4 wt.% SiC, W—4 wt.% SiC—1 wt.% Y2O3 and W—4 wt.% SiC—5 wt.% Y2O3 were mechanically alloyed (MA'd) using a Spex mill for 24 h. MA'd composite powders were sintered under inert Ar and reducing H2 gas conditions at 1680 °C for 1 h. Microstructural and morphological characterizations of composite powders and sintered samples were carried out via SEM and XRD analyses. Furthermore, density measurements and hardness measurements of sintered samples were carried out. A highest Vickers microhardness value of 11.4 GPa was measured for the sintered W—4 wt.% SiC—5 wt.% Y2O3 while W—4 wt.% SiC sample possessed the highest relative density value of 97.7%.

Research highlights► Effects of Y2O3 addition on the W-SiC composites were investigated. ► A relatively low sintering temperature of 1680 °C compared to the literature was used. ► Remarkable relative density and hardness values were measured. ► There was a steady increase in hardness with increasing amount of Y2O3 addition.