The CSA calculation of the bcc Zr-Be phase diagram

Abstract

In the recent years it has been shown that the fcc-based phase diagram can be calculated from the cluster site approximation (CSA) with remarkable accuracy and great computational simplicity over the cluster variation method (CVM). The basis of this method is briefly recalled in this paper. The CSA approximation is applied to estimate the bcc based order disorder phase diagrams of the Be-Zr system. The input parameters are the cluster interactions which are obtained from first principles calculations published recently. We discuss in detail the relationships between the adjustable parameter in this method and the order disorder transition temperature. Calculations of the formation Gibbs energies are carried out for the ordered and disordered phases and are compared with the ones obtained by the CVM method.