A thermodynamic study of the D03-ordered intermetallic compound Fe3Al

Activities of iron were obtained by means of a Gibbs-Duhem integration for the same composition range. The results of the activity measurements were interpreted in terms of a statistical-thermodynamic model for nonstoichiometric phases with the D03-superstructure based on defect formation energies from the literature. It was found that non-stoichiometry in Fe3Al is caused by anti-structure atoms on two of the three possible sublattices.