Cluster/site approximation calculation of the ordering phase diagram for Cd–Mg alloys

We have used the modified cluster/site approximation in a phenomenological calculation of the phase diagram and single phase thermodynamic properties for cadmium–magnesium alloys in the order/disorder region. Values for the three cluster energies differ little from those obtained by LMTO-ASA calculations on unrelaxed alloys of ideal c/a ratio. Only two other parameters contained in contributions to the Gibbs energy are required. One comes from a configuration independent term and the other is an entropy factor coming from the cluster/site approximation.