First-principles calculations and thermodynamic modeling of the Al–Pt binary system

Thermodynamic description of the Al–Pt binary system is modeled by combining first-principles calculations with the CALPHAD method. The four-sublattice and two-sublattice compound energy formalisms are used to model the ordered L12 and B2 phases, respectively. The modeling includes the solution phases and the stoichiometric Al21Pt5, Al21Pt8, Al2Pt, Al3Pt2, AlPt, Al3Pt5 and AlPt2 intermetallic phases. The enthalpy of formation for the stoichiometric compounds and end-members of ordered L12 and B2 phases are calculated from first-principles study. In addition the enthalpies of mixing for the disordered fcc and bcc phases and the ordered L12 and B2 phases are calculated from first-principles study of special quasirandom structures. The obtained phase equilibria and thermodynamic properties are in good agreement with the experimental data in the literature as well as the first-principles calculations from the present work.