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

Abstract

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 446.68kJ/mol or from 380.75 to 423.47kJ/mol with the addition of 0.5wt.%VC or 0.5wt.% 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.