Thermodynamic Description of Fe−Y and Fe−Ni−Y Systems

The Fe−Y and the Fe−Ni−Y systems were assessed by means of the CALPHAD (CALculation of PHAse Diagram) technique. The solution phases, liquid, bcc, fcc and hcp, were described by the substitutional solution model. The binary compounds, Fe17Y2, Fe23Y6, Fe3Y, Fe2Y, Ni17Y2, Ni5Y, Ni4Y, Ni7Y2, Ni3Y, Ni2Y, NiY, Ni2Y3 and NiY3, were treated as stoichiometric compounds. In the Fe−Ni−Y system, the intermetallic compounds were treated as the line compounds (Fe,Ni)mYn by a two-sublattice model. A self-consistent thermodynamic description of the Fe−Ni−Y system was obtained.