Defect energetics for diffusion in CrMnFeCoNi high-entropy alloy from first-principles calculations

Abstract

We investigated the bulk properties and formation, in addition to the migration energies of vacancies in CrMnFeCoNi using first-principles calculations based on the special quasi-random structure (SQS) approach. The ferromagnetic state of this material was more stable than the paramagnetic state, which mainly originates from the increase in the magnetic moment of Cr atoms. Moreover, the average of the vacancy formation energy of each element was almost the same at approximately 2.0 eV while the average of the vacancy migration energy of each element increased with increasing atomic number. As a result, the activation energy increased from Cr to Ni. The lattice distortion around each element, which exhibited a decreasing trend with increasing atomic number, contributed to a reduction of both the formation and migration energy of the vacancies. The downward shift of 3d orbitals during the migration process also contributed to a reduction of the energy barrier.