Standard enthalpies of formation of yttrium alloys, Y-Me (Me = Ru, Rh, Pd, Os, Ir, Pt), by high-temperature calorimetry

The standard enthalpies of formation of yttrium alloys, Y Me (Me = Ru, Rh, Pd, Os, Ir, Pt) were determined by direct synthesis calorimetry at 1473 ± 2 K. The following values of [math] are reported (J/mole of atoms) : Ru2Y5, - (27.3 ± 3.1), RhY, - (76.1 ± 3.4) ; Rh2Y, - (65.4 ± 1.3) ; PdY, - (94.9 ± 3.8) ; Pd4Y3, - (92.8 ± 3.7) ; Pd3Y, - (79.0 ± 6.5) ; Os2Y, - (24.8 ± 2.8) ;IrY, - (65.9 ± 3.8) ; Ir2Y, - (59.4 ± 2.8) ; PtY, - (104 ± 2.3) ; Pt3Y, - (86.9 ± 2.0). The results are compared with the predictions of the models, and with earlier data for some of the corresponding zirconium alloys

Thermodynamic description of the aluminum-barium phase diagram

The Al-Ba system has been assessed by means of the CALculation of PHAse Diagram (CALPHAD) approach. Al4Ba, Al13Ba7, Al5Ba3 and Al5Ba4 have been treated as stoichiometric compounds while a solution model has been used for the description of the liquid, FCC_A1 (Al) and BCC_A2 (Ba) phases. A set of self-consistent thermodynamic parameters are obtained. The calculated phase diagram and thermodynamic properties agree well with the available experimental data

Thermodynamic modelling of the La-Pb Binary system

The thermodynamic modelling of the La-Pb binary system was carried out with the help of CALPHAD (CALculation of PHAse Diagram) method. La5Pb3, La4Pb3, La5Pb4, αLa3Pb4, βLa3Pb4, LaPb2, LaPb3 have been treated as stoichiometric compounds while a solution model has been used for the description of the liquid, BCC and FCC phases. The calculations based on the thermodynamic modeling are in good agreement with the phase diagram data and experimental thermodynamic values

Thermodynamic assessment of the Pd–Y binary system

The Pd–Y system was critically assessed using the CALPHAD technique. The solution phases (liquid, b.c.c., f.c.c. and h.c.p.) were modeled using the Redlich–Kister equation. The intermetallic compounds Pd3Y and PdY, which have homogeneity ranges, were treated as the formula (Pd,Y)0.75(Pd,Y)0.25 and (Pd,Y)0.5(Pd,Y)0.5 by a two-sublattice model with a mutual substitution of Pd and Y on both sublattices. The optimization was carried out in two steps. In the first treatment, Pd3Y and PdY are assumed to be stoichiometric compounds; in the second treatment they are treated by a sublattice model. The parameters obtained from the first treatment were used as starting values for the second treatment. The calculated phase diagram and the thermodynamic properties of the system are in satisfactory agreement with the experimental data

Thermodynamic assessment of the Pd–Y binary system

The Pd–Y system was critically assessed using the CALPHAD technique. The solution phases (liquid, b.c.c., f.c.c. and h.c.p.) were modeled using the Redlich–Kister equation. The intermetallic compounds Pd3Y and PdY, which have homogeneity ranges, were treated as the formula (Pd,Y)0.75(Pd,Y)0.25 and (Pd,Y)0.5(Pd,Y)0.5 by a two-sublattice model with a mutual substitution of Pd and Y on both sublattices. The optimization was carried out in two steps. In the first treatment, Pd3Y and PdY are assumed to be stoichiometric compounds; in the second treatment they are treated by a sublattice model. The parameters obtained from the first treatment were used as starting values for the second treatment. The calculated phase diagram and the thermodynamic properties of the system are in satisfactory agreement with the experimental data