CALPHAD aided mechanical properties screening in full composition space of NbC-TiC-VC-ZrC ultra-high temperature ceramics

High-entropy ceramics (HECs), especially ultrahigh-temperature ceramics, attract much attention from the refractory-materials community. However, current research about HECs focuses on the equimolar system, causing a gap between traditional and high-entropy ultrahigh-temperature ceramics. In this paper, we build the calculation of phase diagrams (CALPHAD) model of lattice parameters and elastic constants using the data from our first-principles calculation in the full composition space of NbC-TiC-VC-ZrC pseudo-quaternary NaCl-type monocarbides. With the aid of the CALPHAD model, we obtain the distribution of lattice parameters, elastic constants, hardness, fracture toughness, and wear resistance over the full composition space and give the maximum and minimum values for each property. Furthermore, the combination of first-principles calculations and CALPHAD modeling demonstrated in this paper provides a feasible paradigm for mapping the composition-property relationship, which can be applied in other HECs, such as high-entropy nitrides and high-entropy borides.