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

Abstract

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 L1 2 and B2 phases, respectively. The modeling includes the solution phases and the stoichiometric Al 21Pt 5, Al 21Pt 8, Al 2Pt, Al 3Pt 2, AlPt, Al 3Pt 5 and AlPt 2 intermetallic phases. The enthalpy of formation for the stoichiometric compounds and end-members of ordered L1 2 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 L1 2 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.