2013 Volume 54 Issue 5 Pages 647-655
A thermodynamic analysis of phase equilibria in the Mg–Al–Ho ternary system has been carried out with special emphasis on the metastable phase separation of the hexagonal close-packed (hcp) phase. In this study, the Gibbs free energy of mixing of the hcp phase was evaluated using first-principles calculations combined with the cluster variation method (CVM), and the obtained results as well as the available experimental data were introduced into the analysis. The calculated results enabled the reproduction of experimental results on both the phase equilibria and the thermodynamic properties obtained from the first-principles calculations and the CVM. In addition, the calculations indicated a tendency for metastable two-phase separation in the hcp phase between the Mg-rich corner and the Al–Ho binary side, which was similar to the Mg–Y–Zn ternary system shown in our previous work.