Single-phase stability and point defect characteristics in high-entropy carbide ceramics

In this work, we calculated the lattice distortion and thermodynamic parameters of 28 senary high-entropy transition metal carbide ceramics (HETMCCs) using first-principles methods. These calculations were compared with the experimentally measured phase compositions, leading to the establishment of a new criterion for predicting the stability of single-phase. We determined the energies associated with the formation and migration of point defects in HETMCCs and conducted a comparative analysis with those of Transition metal carbide ceramics (TMCs). Our findings indicate that the energies associated with point defect formation in HETMCCs consistently fall between the maximum and minimum values observed for TMCs, with the exception of carbon interstitials. Furthermore, the migration energies for carbon vacancies in HETMCCs are greater than those found in TMCs, which serves to effectively hinder the long-range diffusion of vacancies and enhance the material's resistance to irradiation.