A large database of solute-vacancy binding energies, deduced from first-principles density functional calculations, was reported. The calculated binding energies agreed well with accurate measurements where available, and provided an accurate predictor of solute-vacancy binding in other systems. It was found that some common solutes (Cu, Mg) in commercial Al-alloys possessed either very weak (Cu), or even repulsive (Mg), binding energies. Hence, it was suggested that some previously reported large binding energies for these solutes were incorrect. Large binding energies were found for Sn, Cd and In; thus confirming the proposed mechanism for reduced natural aging in Al-Cu alloys which contained micro-alloying additions of these solutes. In addition, it was predicted that a similar reduction in natural aging should occur with additions of Si, Ge and Au. Even larger binding energies were found for other solutes (Pb, Bi, Sr, Ba), but these solutes exhibited essentially no solubility in Al. It was found that there was a strong correlation between the binding energy and solute size; with larger solute atoms exhibiting stronger bonding with vacancies. Most transition-metal 3d solutes did not bond strongly with vacancies, and some were even strongly repelled from vacancies; particularly Ti and V.

Solute–Vacancy Binding in Aluminium. C.Wolverton: Acta Materialia, 2007, 55[17], 5867-72