Vacancy concentration in Al–Mg solid solutions

The thermodynamically stable vacancy concentration is evaluated in Al–Mg solid solutions by means of atomistic simulations. The results are compared with data inferred from experiments based on various models. It is shown that, in the presence of solute clustering, the stable vacancy concentration within the cluster may be orders of magnitude larger than the mean concentration in the absence of clusters. This assists local solute diffusion. The result is relevant for the mechanism of dynamic strain aging in solid solutions.