CALPHAD/first-principles re-modeling of the Co–Y binary system

Abstract The thermodynamic properties and phase diagram of the Co–Y system have been analyzed by the CALPHAD technique using a computational optimization procedure via the ThermoCalc software package. Based on the experimental data, nine intermetallic phases were taken to be stoichiometric compounds and two phases, Co 5 Y and Co 17 Y 2 were described with three-sublattice models. First-principles calculations were obtained for the enthalpy of formation of five stable Co–Y compounds and the calculated end members of the Co 5 Y phase. The model accounts for the magnetic contribution of Co 7 Y 2 , Co 5 Y and Co 17 Y 2 . The thermochemical and equilibrium information in the CoY system has been accurately reproduced and is shown to be in agreement with all experimentally validated phase reactions.