Preparation temperature, mechanical properties and oxidation behaviour of (MoNbTiVZrW)C high entropy ceramics

(MoNbTiVZrW)C high-entropy ceramics were prepared by high-energy ball milling (HEBM) and discharge plasma sintering (SPS) using carbide powders as raw materials, and the effects of sintering temperature (1600~2000°C with 100°C interval) on the organisation and mechanical properties of high-entropy ceramics were investigated. The results show that during the sintering process, except for a small amount of ZrC being oxidized, the lowest temperature at which the carbides are fully solidified is 1800°C, and the sintered samples are dominated by (MoNbTiVZr)C high-entropy ceramic phases of FCC structure.The densities of (MoNbTiVZr)C high-entropy ceramics sintered at 1600~2000°C are all more than 97%, and the average grain sizes are increased with the increase of sintering temperature. The average grain size increases with the increase of sintering temperature, and the hardness and fracture toughness show a decreasing trend with the increase of sintering temperature. When the sintering temperature is 1800 ℃, the comprehensive mechanical properties of the prepared ceramics are better, and the hardness and fracture toughness can be up to 20.86 ± 0.74 GPa and 4.90 ± 0.21 MPa-m1/2, respectively.The oxidation temperature of (MoNbTiVZrW)C high-entropy ceramics prepared at 1800 ℃ is about 480 ℃, and the oxidation weight gain reaches the maximum at 830 ℃.