High-entropy boride-carbide based composite prepared by reactive spark plasma sintering

Abstract

(Hf0.2Zr0.2Ta0.2Nb0.2Ti0.2)C-(Hf0.2Zr0.2Ta0.2Nb0.2Ti0.2)B2-SiC (HEBC-SiC) and (Hf0.2Zr0.2Ta0.2Nb0.2Ti0.2)B2-SiC (HEB-SiC) high-entropy boride-carbide composites were prepared by reactive spark plasma sintering with high-entropy carbides, B4C and Si as starting materials. Compared to monolithic (Hf0.2Zr0.2Ta0.2Nb0.2Ti0.2)C ceramics, both HEBC-SiC and HEB-SiC samples exhibited lower porosity and finer grain size due to mutual phase pinning effect. Also, the HEBC-SiC sample possessed superior mechanical properties compared to (Hf0.2Zr0.2Ta0.2Nb0.2Ti0.2)C ceramics, which demonstrated a hardness of 24.95 GPa (vs 20.18 GPa) and fracture toughness of 4.16 MPa·m1/2 (vs 2.94 MPa·m1/2). The present study provided a new approach to obtain dense (Hf0.2Zr0.2Ta0.2Nb0.2Ti0.2)C-(Hf0.2Zr0.2Ta0.2Nb0.2Ti0.2)B2-SiC composites with enhanced mechanical properties.