Effects of Cr₃C₂ and V₈C₇ on the Microstructure and Mechanical Properties of WC-SiC Whisker Ceramics

Abstract

WC-SiC whisker ceramics (5 vol% SiC) containing Cr₃C₂ and/or V₈C₇ with no metallic binders were prepared by resistance-heated hot pressing at 1650°C and were examined with regard to sinterability, microstructure and mechanical properties. The addition of Cr₃C₂ or V₈C₇ brought about an increase or decrease in the sinterability. For equal molar amounts of Cr and V, V₈C₇ more strongly inhibited the growth of WC grains than Cr₃C₂. The hardness of the ceramics was dependent on the WC grain size which was influenced by the nature or quantity of the additives. The hardness values are consistent with the Hall-Petch-type relationship between hardness and WC grain size estimated for WC phases in WC-Co cemented carbides.