Thermodynamic modeling of the Cu–Si system

The thermodynamic description of the Cu–Si system has been updated with first-principles calculations of the ϵ-Cu15Si4 phase and solid solution phases. Calculated enthalpy of formation for the ϵϵ-phase indicates that enthalpies of formation for intermetallic compounds in Cu–Si must be negative, which were evaluated as positive in the previous thermodynamic modelings. Enthalpies of mixing for the solid solution phases, bcc, fcc, and hcp, are also calculated from first-principles study of Special Quasirandom Structures (SQS) and all the solution phases exhibit similar mixing behavior. It is concluded that first-principles calculations of solid phases including solution phases can supplement scarce experimental data and be readily used in thermodynamic modelings.