A new calculation technique, that was based upon the cluster variation method, was developed in order to calculate the vacancy concentrations in B2-type ordered alloys. A critical step in obtaining a solution was to determine the vacancy concentration at which the chemical potential in the alloys vanished. By using this method, together with a set of suitable interaction parameters for each nearest-neighbor or second-nearest neighbor atom-atom or atom-vacancy pair, it was easy to calculate the vacancy concentration in these alloy systems. This contrasted with the usual method, which was more sophisticated in that it dealt with an open system with respect to the number of vacancies.

T.Shinoda, H.Hosoda, Y.Mishima: Materials Science and Engineering A, 1995, 192-193, 930-5