Medium-entropy carbide ceramics have garnered significant attention due to their outstanding mechanical and chemical properties. However, the underlying physical mechanisms responsible for their excellent mechanical properties have not been fully understood. In this study, we performed first-principle calculations to systematically determine the lattice constants, mechanical properties, electronic density of states, and charge densities of two refractory medium-entropy carbide ceramics: (NbTaW)C and (MoTaW)C. Our calculated results were in good agreement with the experimental data. We demonstrated that medium-entropy carbide ceramics exhibit superior mechanical properties compared to those of high-entropy alloys, primarily due to the introduction of C, which induces a more pronounced lattice distortion effect within the material. This effect facilitates charge transfer between metal cations and nonmetal anions, leading to stronger covalent bonds that enhance the mechanical properties. Our study elucidates the physical mechanisms governing the exceptional mechanical properties of novel refractory medium-entropy carbide ceramics and guides their design and development.

文章链接：Microstructure and mechanical properties of novel medium-entropy carbide ceramics - ScienceDirect