Synergistic effects of high-entropy alloy addition on hardness and fracture toughness of (Ti,Nb,Ta,Mo,W)(C,N)-based high-entropy ceramics

High hardness and high toughness (Ti,Nb,Ta,Mo,W)(C,N)-based ceramics were prepared using pre-synthesized high-entropy carbonitride (HECN) powder and high-entropy alloy (HEA) via spark plasma sintering. By HEA addition of 5 vol%, dense (Ti,Nb,Ta,Mo,W)(C,N)-based ceramics with fine microstructure was obtained at 1450 degrees C. Due to the presence of the precipitated (Mo,W)2C phase within the HECN matrix, which forms a solid solution with the added HEA, the ceramics exhibited the high Vickers hardness (24.5 +/- 1.3 GPa) and fracture toughness (6.1 +/- 0.4 MPa m1/2), arise from the fine grain structure of the ceramics and the pronounced effect of crack deflection. This study introduced a new strategy for the preparation of high-entropy carbonitride-based ceramics, which significantly improved the fracture toughness while maintained high hardness.

Automated summary

High hardness and high toughness (Ti,Nb,Ta,Mo,W)(C,N)-based ceramics were prepared using pre-synthesized high-entropy carbonitride (HECN) powder and high-entropy alloy (HEA) via spark plasma sintering, and the fracture toughness of the ceramics was significantly improved.