Fine-grained dual-phase high-entropy ceramics derived from boro/carbothermal reduction

In the current work, fine-grained dual-phase, high-entropy ceramics (Ti0.2Zr0.2Hf0.2Nb0.2Ta0.2)B2-(Ti0.2Zr0.2Hf0.2Nb0.2Ta0.2)C with different phase ratios were prepared from powders synthesized via a boro/carbothermal reduction approach, by adjusting content of B4C and C in precursor powders. Phase compositions, densification, microstructure, mechanical properties investigated correlated. Due to combination pinning effect average grain size (?0.5?1.5 ?m) dual-phase was roughly one order magnitude smaller than previously reported literature. The had residual porosity ranging 0.3 3.2 % upon sintering SPS material about 18 vol% boride exhibited highest Vickers hardness (24.2±0.3 GPa) fracture toughness (3.19±0.24 MPam1/2).