Interactions of solute (3p, 4p, 5p and 6p) with solute, vacancy and divacancy in bcc Fe

Solute–vacancy binding energy is a key quantity in understanding solute diffusion kinetics and phase segregation, and may help choice of alloy compositions for future material design. However, the binding energy of solute with vacancy is notoriously difficult to measure and largely unknown in bcc Fe. With first-principles method, we systemically calculate the binding energies of solute (3p, 4p, 5p and 6p alloying solutes are included) with vacancy, divacancy and solute in bcc Fe. The binding energy of Si with vacancy in the present work is in good consistent with experimental value available. All the solutes considered are able to form stable solute–vacancy, solute–divacancy complexes, and the binding strength of solute–divacancy is about two times larger than that of solute–vacancy. Most solutes could not form stable solute–solute complexes except S, Se, In and Tl. The factors controlling the binding energies are analyzed at last.