Role of nano-WC addition on microstructural, mechanical and thermal characteristics of TiC–SiC_w composites

In this research, various amounts of nano-sized tungsten carbide (WC_n: 0, 1.5, and 3 wt%) were added to TiC-10 vol% SiC_w system. All samples were sintered at 1900 °C under an external pressure of 40 MPa for 7 min by spark plasma sintering (SPS) procedure. Microstructural, thermodynamical, and XRD evaluations revealed the formation of non-stoichiometric TiC_x, in-situ TiC, SiC, and WSi₂. The carbon exited the TiC lattice owing to the formation of non-stoichiometric TiC_x precipitated at the grain boundaries. Although introducing 1.5 wt% WC_n enhanced the relative density of TiC-SiC_w (98.7%) by around 0.7%, further addition of this sintering aid had a destructive impact. The addition of WC_n decreased both hardness and flexural strength of the specimens, and the poorest values (11.6 GPa and 368 MPa, respectively) were recorded for TiC-10 vol% SiC_w-3 wt% WC_n. The highest thermal conductivity (24.3 W/m.K) was obtained by the addition of 1.5 wt% WC_n.