It was pointed out that this material was in an homogeneous thermodynamically stable equilibrium state. Because of the very slow annealing kinetics in the material, this was not an obvious deduction. The change in vibrational entropy due to defects was neglected, and no correlations in the arrangements of the various defects were considered. The latter assumption was only roughly valid at low defect concentrations. The defect energetics evolved via the breaking and formation of configurationally independent interaction energies between pairs of nearest-neighbour atoms or nearest-neighbour vacancies.

Structural Vacancies in B2 CoAl and NiAl. B.Meyer, G.Bester, M.Fähnle: Scripta Materialia, 2001, 44[10], 2485-8