Monte Carlo Study of the Phase Diagrams of Binary Alloys with Face-Centered Cubic Lattice Structure.

The authors describe the results of Monte Carlo computations of the coherent phase diagram in the temperature-composition plane of ordering binary alloys on a face-centered cubic lattice. Results on long- and short-range order parameters as well as ordering energies are also given. They consider the system with nearest neighbor interaction in the grand-canonical ensemble equivalent to an Ising antiferromagnet in a magnetic field as well as in the canonical ensemble fixed composition. Results with next-nearest neighbor interaction are also given, and for both models a comparison with other available predictions is made, particularly with the cluster-variation method. While the latter is found to be quite accurate at stoichiometric composition, it appears to do less well in the more general case. The tetrahedral approximation of the cluster variation method predicts a topology of the phase diagram, in the case of nearest-neighbor interaction different from the computer simulations. Some consequences for the interpretation of the behavior of copper-gold alloys are indicated. Author