Thermodynamic Assessment of the Ti-Ir System

The thermodynamic assessment of the binary system Ti-Ir has been carried out by modeling the Gibbs energy of all individual phases using the calculation of phase diagrams approach based on the available literature data including the phase equilibria and thermodynamic properties. The Gibbs free energies of the liquid, bcc, fcc and hcp phases were described by the subregular solution model with Redlich-Kister formula, and those of the intermetallic compounds (Ti₃Ir, γTiIr, βTiIr and TiIr₃) in the Ti-Ir binary system were described by the two-sublattice model. The calculations are in good agreement with the literature data on both phase equilibria and thermodynamic properties in the Ti-Ir system.     

Thermodynamic Modeling of the Succinonitrile-Water System

Succinonitrile-water (SCN-H₂O) system is a widely used transparent metallic alloy system due to its analog solidification behavior to metals. In the present work, Gibbs energy of pure succinonitrile was derived utilizing temperature as well as enthalpy of transformations, and temperature dependencies of heat capacity available in the literature. The phase diagram for the binary SCN-H₂O system was assessed via the CALPHAD approach using phase equilibrium data available in the literature. Self-consistent thermodynamic parameters were obtained. A good agreement between the experimental and calculated data for the phase diagram has been achieved. The present work contributes to the development of the thermodynamic database of the SCN-H₂O system that can be incorporated into thermodynamic and kinetic codes for computational simulations.     

Thermodynamic assessment of the Ni-Ga system

Phase diagram and thermodynamic properties of the Ni-Ga system are assessed based on the CALPHAD approach, using all available experimental data and applying appropriate thermodynamic models. The liquid phase and the Ni-based solid solution (Ni) are treated as disordered solutions. The thermodynamic behavior of the ordered intermetallic compounds with appreciable ranges of homogeneity, Ni₃Ga and NiGa, are described by a two-sublattice model, and the order-disorder transformation between Ni₃Ga and fcc-(Ni) is also explicitly considered in this work. The other five intermetallic compounds are treated as stoichiometric line compounds. The phase diagram and the thermodynamic properties calculated from the optimized model parameters are in good agreement with most of the experimental data.     

Thermodynamic modeling of Ru–Zr and Hf–Ru systems

In this paper, an assessment of the binary Ru–Zr and Hf–Ru systems is presented. The thermodynamic evaluation is based on diagrammatic investigations and high-temperature calorimetric measurements for the formation of the three intermediate compounds. The present work proposes thermodynamic modeling of the binaries calculated according to the CALPHAD method and carried out using the PARROT module in the Thermo-Calc software. The liquid phase and the solution phases (Ru)-HCP-A3, (Zr)-HCP-A3, (βZr)-BCC-A2, (Hf)-HCP-A3 and (βHf)-BCC-A2 are treated as substitutional solutions. The intermetallic Laves phase Ru₂Zr-C14 is modeled with the sublattice formalism. The RuZr-B2 and HfRu-B2 phases are treated as ordered phases originating, respectively, from (βZr)-BCC-A2 and (βHf)-BCC-A2 disordered phases. Considering the relative uncertainty of experimental data due to high temperatures, a good agreement is obtained between calculated and experimental phase diagrams. The optimized set of coefficients and the calculated isothermal section are provided.     

First-principles investigation of the Cu–Ni,Cu–Pd,and Ni–Pd binary alloy systems

Phase diagrams of copper–nickel–palladium binary alloys were determined by density functional theory cluster expansion method. The system has both magnetic and non-magnetic binaries and subtle phase coexistence areas between similar and different kind of lattice types. Furthermore, the CuPd binary has several ordered structures. Cluster expansion models were constructed by heuristic cluster selection for all of the fcc structures and for the CuPd_bcc structure. Both configurational and magnetic phase diagrams were determined. Small amount of nickel magnetize fcc palladium to 0.26 μ_B from which the magnetic moment rises almost linearly to that of pure Ni. In CuNi, 0.46 x-Ni is needed for the magnetic transition. In CuPd alloy in 0 K, configurational free energy difference between bcc and fcc lattice resulting to phase separation is only about 1.1 kJ/mol-atoms. Low temperature energetics and magnetic phase diagrams have good quantitative agreement with available experimental and theoretical results. Finite temperature properties of the alloys are in good qualitative agreement with experimental results.     

Optimization of thermodynamic properties of the K2O-SiO2 system at high temperatures

An optimized set of thermodynamic functions for the K₂O-SiO₂ system at 10⁵ Pa pressure was obtained by considering available phase diagram and thermodynamic data. KSi_0.25O and SiO₂ were selected as components for the liquid phase. With respect to these components, the highly non-ideal interactions of potassium oxide and silica could be described by using only three temperature-independent Redlich-Kister coefficients for the excess G of the liquid phase. The result is in good agreement with experimental data.     

Optimization of thermodynamic properties of the K2O-SiO2 system at high temperatures

An optimized set of thermodynamic functions for the K₂O-SiO₂ system at 10⁵ Pa pressure was obtained by considering available phase diagram and thermodynamic data. KSi_0.25O and SiO₂ were selected as components for the liquid phase. With respect to these components, the highly non-ideal interactions of potassium oxide and silica could be described by using only three temperature-independent Redlich-Kister coefficients for the excess G of the liquid phase. The result is in good agreement with experimental data.     

A thermodynamic assessment of Ce-Al system

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Thermodynamic assessment of the Gd–Sb system

A thermodynamic assessment of the binary Gd–Sb system was performed through the CALPHAD approach (CALculation of PHAse Diagram) based on the evaluation of all phase diagram data and available thermodynamic data in the literature. The liquid, hcp-A3 (αGd) and bcc-A2 (βGd) phases were described by a substitutional solution model. All the intermediate phases, Gd₅Sb₃, Gd₄Sb₃, βGdSb, αGdSb and Gd₁₆Sb₃₉, were treated as stoichiometric compounds. A set of self-consistent thermodynamic parameters of the Gd–Sb system has been obtained. A good agreement is obtained between the experimental and the calculated phase diagrams.     

Thermodynamic evaluation of the Cu-R (R: Ce, Pr, Nd, Sm) binary systems

The phase diagrams and thermodynamic properties of the Cu-R (R: Ce, Pr, Nd, Sm) systems are reevaluated on the basis of all available experimental data, including the enthalpies of mixing reported recently. The Redlich-Kister polynomial with two or three terms is used to describe the excess Gibbs energies of liquid phases in the Cu-R systems. All intermediate phases are treated as stoichiometric, and their Gibbs energies of formation are optimized. Based on the optimized thermodynamic parameters, phase diagrams and thermodynamic properties of the Cu-R systems are calculated and compared with the experimental results. The optimized parameters seem to be in good agreement with the experimental data and might represent the regularity and systematic variation of these systems.     

Thermodynamic assessments of the Cu–Th and Mo–Th systems

The thermodynamic assessments of the Cu–Th and Mo–Th binary systems were carried out by using Calculation of Phase Diagrams (CALPHAD) method on the basis of the experimental data including the thermodynamic properties and phase equilibria. The Gibbs free energies of the liquid, bcc, and fcc phases are described by the subregular solution model with the Redlich–Kister equation and those of the four intermetallic compounds Cu₆Th, Cu_3.6Th, Cu₂Th and CuTh₂ in the Cu–Th binary system were described by the sublattice model. A set of self-consistent thermodynamic parameters are obtained, and the calculated phase diagrams and thermodynamic properties are presented and compared with the experimental data from literatures. The calculated thermodynamic properties as well as phase diagrams are in good agreement with the experimental data.     

Thermodynamic analysis and assessment of the Ce–Ni system

An optimised set of thermodynamic parameters for the Ce–Ni system has been obtained using the CALPHAD approach. A thorough thermodynamic analysis of the system has been carried out using different calorimetric techniques and the data have been used in the assessment. The free energy of the liquid phase has been described as a function of temperature and composition using a Redlich–Kister polynomial. Solid compounds have been considered as stoichiometric with the exception of the Laves phases. The phase diagram and thermodynamic quantities calculated from assessed parameters agree well with experimental data.