A practical guideline for designing high-entropy carbides based on (Ti1/3Mo1/3W1/3)C with high valence electron concentration

Introduction of high entropy and high valence electron concentration (VEC) design criterion into TiC ceramic is a promising method for further improving its thermal stability and mechanical performance. Herein, structural, mechanical, electronic properties and stability of (M _0.25Ti _0.25Mo _0.25W _0.25 )C (M=Cr, V, Nb, Ta, Zr, Hf) high-entropy carbides (HECs) were systematically investigated by combining density functional theory (DFT) and experimental method. All of the six HECs are stable. Among them, (Ta _0.25Ti _0.25Mo _0.25W _0.25 )C owns the highest melting temperature, ductility and the best fracture toughness. (Zr _0.25Ti _0.25Mo _0.25W _0.25 )C possesses the highest friction strength and excellent hardness. (Hf _0.25Ti _0.25Mo _0.25W _0.25 )C exhibits the highest hardness and compressive strength as well as good fracture toughness. In addition, (Cr _0.25Ti _0.25Mo _0.25W _0.25 )C was successfully fabricated to further prove the synthesizing feasibility of all samples in this study, and formation mechanism of the monophasic carbide solid solutions was probed. This research provides instructive information for further developing TiC ceramics and designing high-entropy carbides with high VEC with excellent mechanical performance.