Preparation and mechanical properties of (Ti0.2Zr0.2V0.2Nb0.2Ta0.2)(C0.6N0.4)-Co high-entropy cermets

A novel (Ti0.2Zr0.2V0.2Nb0.2Ta0.2)(C0.6N0.4)-Co high-entropy cermets were prepared by two-steps method and the microstructure and mechanical properties were investigated. The single-phase high-entropy carbonitride (HECN) (Ti0.2Zr0.2V0.2Nb0.2Ta0.2)(C0.6N0.4) powders were synthesized at 1600 degrees C. Subsequently, the HECN-Co cermets were successfully fabricated by the pressureless sintering technique. The results revealed that HECN powders (grain size similar to 0.79 mu m) with uniform composition could be prepared at a lower temperature (1600 degrees C) by using oxide and carbon powders as raw materials. This preparation method also maintained the oxygen content and free carbon at low levels of 0.13 wt% and 0.03 wt%, respectively. The HECN-Co high-entropy cermets sintered at 1500 degrees C showed uniform distribution of the metal phase along the ceramic phase and good denseness (apparent porosity of only 0.08%). In addition, the samples possessed excellent mechanical properties, with hardness and fracture toughness of 15.72 GPa and 12.9 MPa.m(1/2). Because of the unique features of high-entropy ceramics and the effective combination of ceramic and metal phases, HECN-based high-entropy cermets offer excellent overall properties.

Automated summary

A novel high-entropy cermets material was prepared using a two-steps method, and its microstructure and mechanical properties were investigated. The results showed that the material had uniform composition, good denseness, and excellent mechanical properties.