Textured and toughened high-entropy (Ti0.2Zr0.2Hf0.2Nb0.2Ta0.2)C-SiCw ceramics

High-entropy (Ti0.2Zr0.2Hf0.2Nb0.2Ta0.2)C ceramics, with different contents (0, 5, 10, and 20 vol.%) of SiC whiskers (SiCw), were fabricated by spark plasma sintering using raw powders synthesized via carbothermal reduction. The application of a uniaxial compaction force led to texture development of the SiCw within the (Ti0.2Zr0.2Hf0.2Nb0.2Ta0.2)C matrix. Fracture toughness increased with the increase in SiCw content, while Vickers hardness remains almost unchanged. The toughness of (Ti0.2Zr0.2Hf0.2Nb0.2Ta0.2)C-20 vol.% SiC, ceramics reached 4.3 +/- 0.3 MPa m(1/2), which was approximately 43% higher than that of the monolithic (Ti0.2Zr0.2Hf0.2Nb0.2Ta0.2)C ceramic (3.0 +/- 0.2 MPa m(1/2)). The main toughening mechanisms were attributed to crack deflection, whisker debonding, and whisker pullout. (C) 2021 Published by Elsevier Ltd on behalf of Chinese Society for Metals.

Automated summary

High-entropy (Ti0.2Zr0.2Hf0.2Nb0.2Ta0.2)C ceramics were fabricated with varying amounts of SiC whiskers, leading to an increase in fracture toughness while maintaining nearly unchanged Vickers hardness. The toughness of the ceramic with 20% SiC content was approximately 43% higher than that of the monolithic ceramic. The main toughening mechanisms were crack deflection, whisker debonding, and whisker pullout.