First-principles electronic-structure approach for phase diagrams of binary alloys

A combined statistical-mechanical and electronic-structure approach for the first-principles calculation of binary-alloy phase diagrams is presented. The grand partition function, constructed from volume-dependent internal energies obtained from local-density total-energy supercell calculations, permits the determination of the entropy and thus, in principle, all thermodynamic quantities. Illustrative results of first calculations for the Al-Li system show: (i) structural properties versus concentration in very good agreement with experiment and (ii) features on the Al-rich side of the phase diagram of the fcc solid solution which are important for alloy formation.