Densification, microstructure and mechanical properties of multicomponent (TiZrHfNbTaMo)C ceramic prepared by pressureless sintering

A multicomponent (TiZrHfNbTaMo)C ceramic has been fabricated by pressureless sintering at temperatures from 2100 °C to 2500 °C, using an equimolar multicomponent carbide powder synthesized by carbothermal reduction as the starting material. Influence of sintering temperature on densification, microstructure and mechanical properties of the ceramics was investigated. The relative density increases with increasing sintering temperature, and a nearly fully dense sample is achieved by pressureless sintering at 2500 °C. Average grain size increases from 3.7 to 15.2 μm with increasing sintering temperature from 2300 to 2500 °C. The (TiZrHfNbTaMo)C ceramic sintered at 2400 °C exhibits a single phase fcc structure with homogeneous chemical composition, an average grain size of 7.0 μm and a relative density of 96.5%, while its measured hardness is 33.2 GPa at 100 mN and 23.2 GPa at 9.8 N.