Understanding the electronic structure, mechanical properties, and thermodynamic stability of (TiZrHfNbTa)C combined experiments and first-principles simulation

Abstract

An equimolar high-entropy carbide, (TiZrHfNbTa)C, which is a face-centered-cubic-structured solid solution, was synthesized through spark plasma sintering at 1950 °C. Its electronic properties, thermodynamic stability, and mechanical properties were thoroughly investigated by well-defined density functional theory calculations. Our results show that the strong bonds of TM-C (TM = Ti, Zr, Hf, Nb, Ta) in (TiZrHfNbTa)C lead to excellent mechanical properties relative to those of TaC, the solid-solution template, and limited lattice distortion, making its electronic structure similar to those of the constituent carbides. Calculated Young's modulus (495 GPa) matches the experimental measurement data (479 GPa) well. This work provides insight into high-entropy (TiZrHfNbTa)C on an electronic scale and paves the way for the design of novel high-entropy carbides.