| Abstract Scope |
Point defects govern diffusion, irradiation response, creep, and phase stability in MAX phases, yet the influence of chemistry on defect energetics across the 211 MAX-phase family remains poorly understood. We present a high-throughput first-principles investigation of intrinsic point defects in 211 carbides and nitrides. Vacancy formation energies and nudged elastic band migration barriers are computed for the M, A, and X sublattices using a consistent density functional theory workflow. The resulting dataset reveals chemistry-driven trends in defect formation, migration, and diffusion activation energies, enabling composition–property maps for identifying promising MAX phases with tailored defect transport characteristics. Representative compositions are investigated to elucidate the underlying atomistic mechanisms. Finally, machine-learning surrogate models are developed to predict defect energetics in mixed M- and A-site MAX phases and are validated through targeted first-principles calculations, providing a predictive framework for computational design of MAX phases. |