Thermodynamic assessment of the Zn–Y and Al–Zn–Y systems

The phase diagram in the Zn–Y binary system has been evaluated by using the CALPHAD (Calculation of Phase Diagrams) method with the experimental data of the phase equilibria and thermodynamic properties. The Gibbs free energies of the liquid, bcc and hcp phases were described by the subregular solution model with the Redlich–Kister equation, and those of the eight stoichiometric compounds of the YZn, YZn2, YZn3, Y3Zn11, Y13Zn58, YZn5, Y2Zn17 and YZn12 were described by the sublattice model. The thermodynamic parameters in the Al–Zn–Y system were also evaluated by combining the experimental data with the parameters in three binary systems. The calculated phase equilibria and thermodynamic properties are in good agreement with the experimental data.