A large database of solute–vacancy binding energies in Mg arising from first-principles calculations based upon density functional theory was presented. The vacancy formation energy and dilute mixing energy, which were by-products of the solute–vacancy binding calculations, showed good agreement with experiments, where available. An investigation was made of the simple physical effects controlling solute–vacancy binding in Mg and it was found that there was a modest correlation between binding energy and solute size, with larger solute atoms more favourably binding with neighbouring vacancies to relax the strain induced by the solutes. Most early 3d transition metal solutes do not favourably bind with vacancies, indicating that a simple bond-counting argument was not sufficient to explain the trends in binding, in contrast to the case of binding in Al. Also, positive vacancy binding energies were predicted for some commonly used microalloying elements in Mg which were known to improve age hardenability, i.e. Na, In, Zn, Ag and Ca. Even larger vacancy binding energies were found for some other solutes (e.g. Cu, Sn, Pb, Bi and Pt), which await experimental validation.

First-Principles Study of Solute–Vacancy Binding in Magnesium. D.Shin, C.Wolverton: Acta Materialia, 2010, 58[2], 531-40