Preparation of WC-SiC whisker composites by hot pressing and their mechanical properties

Composites of WC and SiC whisker (0-30 vol% SiC) were prepared at 1550 to 1800 degrees C by using a resistance-heated hot pressing technique called spark plasma sintering. The composites obtained were examined for reaction products and microstructure. and were characterized for mechanical properties. The addition of small amounts of SiC induced the marked grain growth of WC, and drove the densification of WC. Above 10 vol% SiC, dispersed SiC phases impeded the grain growth of WC. Increasing sintering temperature made SiC whiskers thick and lowered the aspect ratio of whiskers. The hardness of composites decreased with increasing average grain size of WC. The Young's modulus of dense composites was decreased with the SiC content. The addition of 3 to 5 vol % SiC greatly increased the fracture toughness of WC.