A first-principles investigation of light weight high mechanical performance high-entropy carbides: The research of bottom-up compositional designing

Abstract

Designing high-entropy carbides with light weight and high mechanical performance is a promising strategy for upgrading titanium carbides applied in fields of aerospace materials. Herein, a bottom-up compositional designing method and the density functional theory calculations are combined, and properties of the six high-entropy carbides are investigated developed from the light-weight (Ti1/3Zr1/3V1/3)C medium-entropy carbide. The five of them are predicted to be preparable except for (W0·25Ti0·25Zr0·25V0.25)C. Among them, (Nb0·25Ti0·25Zr0·25V0.25)C exhibits the both low density and excellent mechanical performance: for density 5.471g/cm3, Young's modulus 456.4GPa, Vicker's hardness 23.76GPa, fractural toughness 3.371MPa∙m1/2, low-temperature and high-temperature friction resistance indicators 0.052 and 0.064GPa, and melting point 3974±300K. The ab-initio simulations also reveal its good high-temperature strength and toughness, showing the predictable potential for upgrading traditional titanium carbide based materials.