Synthesis of high-entropy carbides (TiTaNb)xHfyZrzC with strong thermal-oxidative resistant properties by mechanical alloying and spark plasma sintering

The paper presents the synthesis of single-phase high-entropy carbides (TiZrHfTaNb)C, (TiTaNb)0.45Hf0.275Zr0.275С and (TiTaNb)0.3Hf0.35Zr0.35С by mechanical alloying and spark plasma sintering. High-entropy carbides are promising as a material for jet engine parts. Mechanical alloying mode was obtained, in which the homogeneity of the powder and low technical grinding is achieved.The analysis of the microstructure, phase and chemical composition of the obtained samples was carried out. HEC with an FCC structure and a small content of zirconium and hafanium oxides is formed at a temperature of 1600 °C. Increasing the sintering temperature to 2000 °C promotes the dissolution of oxides and the formation of a single-phase HEC. The microhardness of the samples ranged from 1600 to 2000 HV. The compressive strength of the samples was from 600 to 800 MPa. According to the results of gas dynamic tests, the (TiTaNb)0.3Hf0.35Zr0.35С alloy showed excellent thermal-oxidative resistance up to a temperature of 2250 °C.