Influence of VC and Cr3C2 as grain growth inhibitors on WC-Al2O3 composites prepared by hot press sintering

The effect of VC and Cr3C2 as grain growth inhibitors on the sinterability, microstructure and mechanical properties of WC-Al2O3 composites prepared by hot press sintering was systematically investigated. The results reveal that the decarburization suppression could be achieved with VC or Cr3C2 addition in WC-Al2O3 composites. The rate of densification and grain growth were suppressed, and the apparent activation energy for grain growth increased from 380.75 to 446.68 kJ/mol or from 380.75 to 423.47 kJ/mol with the addition of 0.5 wt.% VC or 0.5 wt.% Cr3C2 during isothermal sintering. With the grain growth inhibits, the microstructure of WC-Al2O3 composites gets finer than that of the undoped. At equal weight portions, VC results in a finer microstructure than Cr3C2. The hardness, fracture toughness and flexural strength of WC-Al2O3 compacts with VC or Cr3C2 grain growth inhibitors were improved.