scholarly journals Thermodynamic modeling of the Fe−Zn system using exponential temperature dependence for the excess Gibbs energy

2011 ◽  
Vol 47 (1) ◽  
pp. 1-10 ◽  
Author(s):  
Y. Tang ◽  
X. Yuan ◽  
Y. Du ◽  
W. Xiong
Keyword(s):  
Experimental Data ◽  
Liquid Phase ◽  
Binary System ◽  
Thermodynamic Properties ◽  
Gibbs Energy ◽  
Excess Gibbs Energy ◽  
Miscibility Gap ◽  
Exponential Equation ◽  
Self Consistent ◽  
Exponential Temperature Dependence

The Fe-Zn binary system was re?modeled using exponential equation Li=hi?exp(-T/?i) (i=0,1,2?) to describe the excess Gibbs energy of the solution phases and intermetallic compounds with large homogeneities. A self-consistent set of thermodynamic parameters is obtained and the calculated phase diagrams and thermodynamic properties using the exponential equation agree well with the experimental data. Compared with previous assessments using the linear equation to describe the interaction parameters, the artificial miscibility gap at high temperatures was removed. In addition, the calculated thermodynamic properties of the liquid phase were more reasonable than those resulting from all the previous calculations. The present calculations yield noticeable improvements to the previous calculations.

scholarly journals Sn-Ni-Bi liquid phase thermodynamic properties

2011 ◽  
Vol 9 (1) ◽  
pp. 149-156 ◽  
Author(s):  
Nikolina Milcheva ◽  
Jolanta Romanowska ◽  
Gueorgui Vassilev
Keyword(s):  
Experimental Data ◽  
Liquid Phase ◽  
Thermodynamic Properties ◽  
Binary Systems ◽  
Isopiestic Method ◽  
Miscibility Gap ◽  
Calphad Approach ◽  
Activity Data ◽  
General Solution Model ◽  
Good Agreement

AbstractExperimental data of bismuth activity coefficients at 1773 K were obtained by isopiestic method and compared to calculated values. Thermodynamic properties of the Sn-Ni-Bi liquid phase were estimated by means of the general solution model and by the methods of Kohler. Description of the ternary liquid phase (Gibbs excess energy dependence on the temperature and the composition) was achieved by using available thermodynamic data of the constitutive binary systems (Ni-Bi, Sn-Bi, Sn-Ni). A comparison between calculated quantities and experimental data wasconducted. The present assessment with thermodynamically optimized values of the system Sn-Ni-Bi (obtained by the CALPHAD approach) was in good agreement. The suggested appearance of a liquid phase miscibility gap at high temperatures is in agreement with the experimental bismuth activity data and with the assessed thermochemical functions.

Extension of a lattice model of electrolytes to a ternary system of a salt and two solvents. The system CH3OH-H2O-LiCl

1989 ◽  
Vol 54 (6) ◽  
pp. 1464-1474
Author(s):  
Ivan Horsák
Keyword(s):  
Experimental Data ◽  
Thermodynamic Properties ◽  
Gibbs Energy ◽  
Ternary System ◽  
Lattice Model ◽  
Excess Gibbs Energy ◽  
Binary Data ◽  
Ternary Systems ◽  
Electrolyte Solutions ◽  
Ternary Contribution

A lattice model proposed to describe the thermodynamic properties of binary electrolyte solutions over the whole concentration range has been extended to ternary systems involving two solvents. The relationships derived for the excess Gibbs energy and the activity coefficients of all the components have been tested with published experimental data on vapour pressures of methanol and water in the system CH3OH-H2O-LiCl at 60 °C. Examination of the ability of the model to predict the behaviour of the ternary system on the basis of binary data has shown that the expression for the excess Gibbs energy must be extended to include a ternary contribution.

scholarly journals Thermodynamic investigation of liquid properties of the Ni–Sn–Ti ternary system using CALPHAD method and geometric models

2016 ◽  
Vol 1 (4) ◽  
pp. 14
Author(s):  
Vanya Gandova
Keyword(s):  
Liquid Phase ◽  
Thermodynamic Properties ◽  
Gibbs Energy ◽  
Excess Gibbs Energy ◽  
Geometric Model ◽  
Calphad Method ◽  
Geometric Models ◽  
Molar Excess Gibbs Energy ◽  
Molar Excess ◽  
Ternary Parameters

Predictions for the liquid Ni–Sn–Ti alloys thermodynamic properties (molar excess Gibbs energy) are presented. The calculations were performed in the temperature range 1000–2000 K.  Geometric models (using data from the binary end-systems) were used and the respective calculated molar excess Gibbs energy values were compared to CALPHAD method assessments. The concentration dependences of the liquid phase thermodynamic properties along different vertical sections Sn:Ti, Ni:Ti and Ni:Sn were estimated.Ternary interaction parameters (L0, L1 and L2) of the liquid phase were determined using General solution (geometric) model from thermodynamic data of the binary end–systems (Ni–Sn, Ni–Ti, Sn–Ti).  Ternary parameters exhibit values: L0 = - 70360.5 - 0.263*T; L1 = -113023 - 11.574*T; L2 = - 131755 - 17.101*T. Negative molar excess Gibbs energies were obtained by all models.

Calphad description of the Ge-Mn system

2014 ◽  
Vol 1642 ◽  
Author(s):  
Alexandre Berche ◽  
Jean-Claude Tédenac ◽  
Philippe Jund ◽  
Stéphane Gorsse
Keyword(s):  
Phase Diagram ◽  
Liquid Phase ◽  
Thermodynamic Properties ◽  
Gibbs Energy ◽  
Critical Review ◽  
Thermodynamic Description ◽  
Calphad Method ◽  
Review Of The Literature ◽  
Solid Phases

ABSTRACTThe germanium-manganese system has been experimentally studied but no Calphad description is available yet. After a critical review of the literature concerning the phase diagram and the thermodynamic properties, a thermodynamic description of the Gibbs energy of the phases is performed using the Calphad method. The liquid phase is described with an associated model and the variation to the stoichiometry of the solid phases is taken into account.

scholarly journals Comparative analyses of thermodynamic properties assessments, performed by geometric models: Application to the Ni-Bi-Zn system

2013 ◽  
Vol 49 (3) ◽  
pp. 347-352 ◽  
Author(s):  
V. Gandova ◽  
G. Vassilev
Keyword(s):  
Experimental Data ◽  
Liquid Phase ◽  
Thermodynamic Properties ◽  
Wide Temperature Range ◽  
Excess Energy ◽  
Energy Calculation ◽  
Thermochemical Properties ◽  
Multicomponent Systems ◽  
Ternary Interaction ◽  
Geometric Models

The thermochemical properties of metals and alloys are essential for the chemists to invent and improve metallurgical and materials? design processes. However, the properties of multicomponent systems are still scarcely known due to experimental difficulties and the large number of related systems. Thus, the modelling of some thermodynamic properties would be advantageous when experimental data are missing. Considering mentioned facts, geometric models to estimate some thermodynamic properties for the liquid phase of the Ni-Bi-Zn systems. The calculations have been performed in a wide temperature range (1000-2000 K). Ternary interaction parameters for the liquid phase allowing molar Gibbs excess energy calculation have been determined.

Evaluation of the Thermodynamic Properties and Phase Equilibria of the Ordered γ’ and Disordered γ Phases in the Ni-Al-Ta System

2002 ◽  
Vol 755 ◽  
Author(s):  
Shihuai Zhou ◽  
Long-Qing Chen ◽  
Rebecca A. MacKay ◽  
Zi-Kui Li u
Keyword(s):  
Experimental Data ◽  
Thermodynamic Properties ◽  
Gibbs Energy ◽  
Phase Equilibria ◽  
Phase Diagrams ◽  
Gibbs Energy Function ◽  
Ternary Interaction ◽  
Two Phases ◽  
Rich Side ◽  
Good Agreement

ABSTRACTThe phase equilibria and thermodynamic properties of the ternary Ni-Al-Ta system on Ni-rich side were analyzed. Thermodynamic descriptions of the liquid, γ-fcc, γ'-L12, and π-Ni6AlTa phases were obtained using the CALPHAD (CALculation of PHase Diagrams) technique. The thermodynamics of γ-fcc and γ'-L12 phases were modeled with a single Gibbs energy function taking into account the crystallographic relation between the two phases. The ternary interaction parameters of the liquid and fcc phases were also determined. The calculated phase diagrams of the ternary Ni-Al-Ta system show a good agreement with experimental data.

scholarly journals First-principles and CALPHAD-type study of the Ir-Mo and Ir-W systems

2020 ◽  
Vol 56 (1) ◽  
pp. 109-118 ◽  
Author(s):  
Y.-Y. Huang ◽  
B. Wu ◽  
F. Li ◽  
L.-L. Chen ◽  
Z.-X. Deng ◽  
...  
Keyword(s):  
Experimental Data ◽  
Thermodynamic Properties ◽  
Thermodynamic Property ◽  
Phase Equilibria ◽  
First Principles ◽  
Critical Evaluation ◽  
Intermetallic Phases ◽  
First Principles Calculations ◽  
Property Data ◽  
Self Consistent

This study presents the thermodynamic modeling of the Ir-Mo and Ir-W systems by means of the CALPHAD (CALculation of PHAse Diagrams) approach supported with the first-principles calculations. A critical evaluation of the phase equilibria and the thermodynamic property data in literature was conducted for both systems. Due to the lack of experimental data, the first-principles calculations were applied to obtain the enthalpies of the solid and intermetallic phases. The thermodynamic parameters were assessed using the PARROT module of Thermo-Calc. A set of self-consistent parameters for the Ir-Mo and Ir-W systems was obtained after the optimization. Satisfactory agreement between the calculated results and the experimental data, including phase equilibria and thermodynamic properties was achieved.

scholarly journals Calculation of the thermodynamic properties of the Ga-Sb-Tl liquid alloys

2005 ◽  
Vol 70 (1) ◽  
pp. 9-20 ◽  
Author(s):  
Dragan Manasijevic ◽  
Dragana Zivkovic ◽  
Katayama Iwao ◽  
Zivan Zivkovic
Keyword(s):  
Thermodynamic Properties ◽  
Gibbs Energy ◽  
Ternary System ◽  
Thermodynamic Model ◽  
Excess Gibbs Energy ◽  
Similarity Coefficient ◽  
Thermodynamic Calculations ◽  
Liquid Alloys ◽  
Geometric Models ◽  
Good Agreement

The results of the calculation of the thermodynamic properties for liquid Ga-Sb-Tl alloys at the temperature 1073 K are presented in this paper. Initially, the most appropriate thermodynamic model for the investigated system was selected. Based on a comparison of the values calculated by different geometric models (Kohler, Muggianu, Toop, Hillert, Chou) with the existing experimental based data, asymmetric models of calculation were determined to give the best results. The asymmetric nature of the investigated ternary system was additionally confirmed by the Chou similarity coefficient concept. For these reasons, further complete thermodynamic calculations were performed according to the Hillert model in five sections of the ternary Ga-Sb-Tl system from each corner with the mole ratio of other two components being 9:1; 7:3; 5:5; 3:7 and 1:9. The obtained results include integral excess Gibbs energy dependences on composition for all the investigated sections. The calculated activity values at 1073 K for all components are given in the form of isoactivity diagrams. Comparison between the calculated and experimentally obtained gallium activities shows good agreement.

scholarly journals Modelling thermodynamic properties of binary Cu–Eu and ternary Al–Cu–Eu melts

2020 ◽  
Vol 8 (2) ◽  
pp. 73-82
Author(s):  
Natalia Kotova ◽  
Natalia Golovata ◽  
Natalia Usenko
Keyword(s):  
Thermodynamic Properties ◽  
Gibbs Energy ◽  
Excess Gibbs Energy ◽  
Model Calculations ◽  
Gibbs Energies ◽  
Excess Gibbs Energies ◽  
Energy Of Mixing ◽  
Gibbs Energy Of Mixing ◽  
Associated Solution Model ◽  
Associated Solution

Model calculations of the whole set of thermodynamic properties of liquid alloys for the binary Cu–Eu and ternary Al–Cu–Eu systems have been performed. Authors used the ideal associated solution model (IAS model) for calculation of the entropies and excess Gibbs energies of mixing for these systems. The binaries were given as the Redlich-Kister polynomials. The thermodynamic properties for the ternary system are described using the Redlich-Kister-Muggianu formalism. A comparison of the surfaces of excess Gibbs energy and entropy of mixing for liquid Al–Cu–Eu alloys at 1350 K demonstrates that the ordering related to the formation of rather strong associates in the Al–Eu system significantly affects the concentration dependence of the excess Gibbs energy of mixing in the liquid phase at this temperature.

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