A 3-dimensional lattice gas model was developed in which the calculations were based upon the assumption that the metal atoms formed a body-centered cubic lattice while the non-metal atoms were adsorbed at octahedral interstices of the metal lattice. It was found that the most striking prediction was that there was a cooperative occupation of the interstices in the case of numerically equal nearest-neighbor and next-nearest neighbor repulsions. Unfortunately, the model did not consider tetragonal distortions and could not account for the tetragonal distortion, of martensites, which was attributed to the preferential occupation of interstices.

C.Uebing: Scripta Metallurgica et Materialia, 1994, 30[9], 1183-8