Mechanical properties of WC–WB–W2B composites prepared by reaction sintering of B4C–W–WC powders

Abstract

Abstract Composites of WC–WB–W 2 B with no metallic binder were prepared by the reaction sintering of a B 4 C–W–WC (mole ratio 1:5:80) powder mixture at sintering temperatures between 1500 and 1900 °C using resistance-heated hot pressing. WB, W 2 B and a part of WC in the composites were formed by the solid-state reaction between B 4 C and W. Dense sintered bodies were obtained at and above 1650 °C, in which small aggregates composed of WB and W 2 B were scattered in WC matrices. The rapid grain growth of WC occurred over a temperature range between 1650 and 1700 °C, and correspondingly resulted in decreases of both the hardness and fracture toughness. The sintering temperature 1650 °C was the most suitable for preparing dense sintered bodies with combined high values of Young's modulus, hardness and fracture toughness.