A Thermodynamic Description of the Al-Ir System

2007 ◽  
Vol 539-543 ◽  
pp. 2389-2394 ◽  
Author(s):  
Taichi Abe ◽  
Machiko Ode ◽  
Hideyuki Murakami ◽  
Chang Seok Oh ◽  
Cenk Kocer ◽  
...  
Keyword(s):  
Experimental Data ◽  
Binary System ◽  
Thermodynamic Assessment ◽  
Thermodynamic Description ◽  
Calculated Data ◽  
Intermetallic Phases ◽  
Sublattice Model ◽  
Calphad Technique ◽  
Formation Enthalpies ◽  
B2 Phase

The thermodynamic assessment of the Al-Ir binary system, one of the key sub-systems of the Ir-based alloys, was performed using the CALPHAD technique. The AlIr(B2) phase was described using the two sublattice model with the formula (Al,Ir)0.5(Ir,Va)0.5, while other intermetallic phases were treated as stoichiometric compounds. The calculated data of the phases in the Al-Ir system can be used to accurately reproduce experimental data, such as phase equilibria, invariant reactions, and formation enthalpies of the intermetallic phases.

scholarly journals Thermodynamic assessment of the Co-Mg binary system

2021 ◽  
pp. 51-51
Author(s):  
L.-F. Yang ◽  
X-D Si ◽  
H.-D. Zhang ◽  
F.-G. Gao ◽  
Y.-P. Zeng ◽  
...  
Keyword(s):  
Experimental Data ◽  
Phase Diagram ◽  
Binary System ◽  
Literature Review ◽  
Thermodynamic Assessment ◽  
Thermodynamic Description ◽  
Thermodynamic Optimization ◽  
Experimental Phase ◽  
Experimental Phase Diagram ◽  
Self Consistent

No thermodynamic description was performed for the Co-Mg binary system according to literature review. Consequently, this binary system has been investigated by means of CALPHAD (CALculation of PHAse Diagrams) approach in the present work. The experimental phase diagram and thermodynamic data available in the literature were critically assessed. Based on the reliable literature data, a new set of self-consistent thermodynamic parameters for the Co-Mg system is obtained. The calculated results agree well with the experimental data from the literature, indicating the reasonability of the present thermodynamic optimization.

scholarly journals A thermodynamic description of metastable c-TiAlZrN coatings with triple spinodally decomposed domains

2017 ◽  
Vol 53 (2) ◽  
pp. 85-93 ◽  
Author(s):  
J. Zhou ◽  
L. Zhang ◽  
L. Chen ◽  
Y. Du ◽  
Z.K. Liu
Keyword(s):  
Experimental Data ◽  
Phase Equilibria ◽  
First Principles ◽  
Thermodynamic Description ◽  
Quantitative Description ◽  
Experimental Phase Equilibria ◽  
Free Energies ◽  
Calphad Technique ◽  
Important Input ◽  
Good Agreement

A critical thermodynamic assessment of the metastable c-TiAlZrN coatings, which are reported to spinodally decompose into triple domains, i.e., c-TiN, c-AlN, and c-ZrN, was performed via the CALculation of PHAse Diagram (CALPHAD) technique based on the limited experimental data as well as the first-principles computed free energies. The metastable c-TiAlZrN coatings were modeled as a pseudo-ternary phase consisting of c-TiN, c-AlN and c-ZrN species, and described using the substitutional solution model. The thermodynamic descriptions for the three boundary binaries were directly taken from either the CALPHAD assessment or the first-principles results available in the literature except for a re-adjustment of the pseudo-binary c-AlN/c-ZrN system based on the experimental phase equilibria in the pseudo-ternary system. The good agreement between the calculated phase equilibria and the experimental data over the wide temperature range was obtained, validating the reliability of the presently obtained thermodynamic descriptions for the c-TiAlZrN system. Based on the present thermodynamic description, different phase diagrams and thermodynamic properties can be easily predicted. It is anticipated that the present thermodynamic description of the metastable c-TiAlZrN coatings can serve as the important input for the later quantitative description of the microstructure evolution during service life.

scholarly journals Thermodynamic Assessment Of The Bi-In-Zn System

2015 ◽  
Vol 60 (2) ◽  
pp. 567-575
Author(s):  
B. Onderka ◽  
A. Dębski ◽  
W. Gąsior
Keyword(s):  
Experimental Data ◽  
Phase Equilibrium ◽  
Thermodynamic Properties ◽  
Phase Equilibria ◽  
Thermodynamic Assessment ◽  
Thermodynamic Description ◽  
Thermal Equilibration ◽  
Heating And Cooling ◽  
Coexisting Phases ◽  
Equilibrium Calculations

Abstract A thermodynamic description of the entire ternary Bi-In-Zn system was obtained by the CALPHAD modelling of the Gibbs energy of the liquid phase. The experimental data on the phase equilibria and the thermodynamic properties published and complemented by the authors’ own experiments were taken into account. In order to verify the phase equilibria in the Bi-In-Zn system, 15 different samples were studied in the temperature range of 300-900 K by the DTA technique during heating and cooling cycles. Coexisting phases and their composition were analyzed by the SEM and EDX techniques for 9 distinct samples after their thermal equilibration at 373 K and 473 K. Assessment and selected phase equilibrium calculations were performed with ThermoCalc and Pandat softwares, and compared with experimental data. The obtained results reproduce well the experimental data on both the phase equilibria and the thermodynamic properties in the optimized system.

Thermodynamic Properties and Thermodynamic Assessment of Ta-Sn System

2013 ◽  
Vol 821-822 ◽  
pp. 849-853 ◽  
Author(s):  
Jian Li Wang ◽  
Bi Yang Tuo ◽  
Xun Pu Hu ◽  
Zhu Lin Liu
Keyword(s):  
Phase Diagram ◽  
Intermetallic Compounds ◽  
Thermodynamic Assessment ◽  
Thermodynamic Description ◽  
Formation Enthalpy ◽  
Mixing Enthalpy ◽  
Temperature Phase ◽  
Formation Enthalpies ◽  
Higher Temperature ◽  
Mixing Enthalpies

For the little thermodynamic information of Ta-Sn system, the liquid mixing enthalpy of Ta-Sn system, and the formation enthalpy of Ta2Sn3 and Ta3Sn were calculated by Miedema model. The Ta-Sn phase diagram was modeled using CALPHAD technology to obtain a reliable thermodynamic description of the system. Two intermetallic compounds Ta2Sn and Ta3Sn were treated as stoichiometric compounds for the very narrow homogeneity ranges. The higher temperature phase diagram of Ta-Sn system was constructed according to Nb-Sn system for the empty information. The optimization process was carried out using the PARRAT software including in Thermo-Calc database system. The thermodynamic calculated Ta-Sn phase diagram is agreement with the evaluated phase diagram, and the calculated mixing enthalpies of molten Ta-Sn system match well with the Miedema data. The formation enthalpies of the two intermetallic compounds Ta2Sn and Ta3Sn are compared with the Miedema values.

Thermodynamic assessment of the MgO–Al2O3–SiO2 system

2005 ◽  
Vol 20 (4) ◽  
pp. 975-986 ◽  
Author(s):  
Huahai Mao ◽  
Olga Fabrichnaya ◽  
Malin Selleby ◽  
Bo Sundman
Keyword(s):  
Experimental Data ◽  
New Species ◽  
Liquid Phase ◽  
Thermodynamic Assessment ◽  
Liquidus Surface ◽  
Sublattice Model ◽  
Ternary Compounds ◽  
Self Consistent ◽  
A New Species ◽  
Consistent Thermodynamic Data

Thermodynamic properties of the phases in the MgO–Al2O3–SiO2 system were assessed, resulting in a set of self-consistent thermodynamic data. The two ternary compounds, cordierite and sapphirine, were optimized from subsolidus reactions. The liquid phase was described by the ionic two-sublattice model with a new species AlO2−1, yielding the formula (Al+3,Mg+2)P(AlO2−1,O−2,SiO4−4,SiO20)Q. Projection of the liquidus surface was calculated. Various isothermal and isoplethal sections were compared with the experimental data.

Thermodynamic Evaluation of the Fe-Pr Binary System

2010 ◽  
Vol 654-656 ◽  
pp. 2442-2445 ◽  
Author(s):  
Guo Jun Zhou ◽  
De Chang Zeng
Keyword(s):  
Experimental Data ◽  
Phase Diagram ◽  
Binary System ◽  
Intermediate Phase ◽  
Eutectic Reaction ◽  
Thermodynamic Description ◽  
Liquid Solution ◽  
Solution Phase ◽  
Mixing Enthalpy ◽  
Thermodynamic Evaluation

The Fe–Pr binary system was thermodynamic evaluation by means of the CALPHAD method based on phase diagram experimental data from the literature and a few values of the mixing enthalpy in the liquid phase obtained by the Miedema theory technique. Each of the selected data values is given a certain weight, which is chosen and adjusted based on the thermodynamic data and diagram phase data. A consistent thermodynamic description of the Fe–Pr binary system is presented: only one intermediate compound, Fe17Pr2, is stable in the system and forms peritectically at 1371K. An eutectic reaction L↔Pr+ Fe17Pr2 occurs at 939K and the eutectic liquid contains 82 at% Pr, five solid solution phases (Fe-rich αFe, γFe and δFe, Pr-rich αPr and βPr) and the liquid solution phase were considered in the evaluation. The intermediate phase was treated as stoichiometric compound, the solid solutions as ideal and the liquid solution phase by the Redlich–Kister formalism. The calculated phase diagram and thermodynamic properties are in good agreement with available experimental data.

scholarly journals On Gibbs Energy for the Metastable bcc_A2 Phase with a Thermal Vacancy in Metals and Alloys

Materials ◽  
2019 ◽  
Vol 12 (2) ◽  
pp. 292 ◽  
Author(s):  
Ying Tang ◽  
Lijun Zhang
Keyword(s):  
Experimental Data ◽  
Binary System ◽  
Gibbs Energy ◽  
Multiple Solutions ◽  
Thermodynamic Description ◽  
Metals And Alloys ◽  
Body Centered Cubic ◽  
Phase Boundaries ◽  
Calculated Phase ◽  
Thermal Vacancy

An approach was proposed to obtain a reasonable thermodynamic description of a thermal vacancy in the metastable disordered body centered cubic (bcc_A2) phase, which had been consistently ignored in previous thermodynamic assessments. The present approach was first applied to obtain the thermodynamic descriptions for pure metastable bcc Ni and Zn, and then in the binary Ni-Zn system. The thermodynamic descriptions for both the metastable disordered bcc_A2 phase and the stable ordered bcc_B2  phases in the Ni-Zn binary system were updated based on the corresponding experimental equilibria. With these updated thermodynamic descriptions, several drawbacks, including the multiple solutions for thermal vacancy concentrations and the artificial phase boundaries in previous assessments, can be avoided. Moreover, the calculated phase boundaries and invariant reactions related to the  phase agree well with the experimental data.

scholarly journals Thermodynamic assessment of the Fe-Nb-Si system

2021 ◽  
pp. 29-29
Author(s):  
Y. Jiang ◽  
F. Li ◽  
S.-R. Li ◽  
K. Xu ◽  
L.-L. Chen ◽  
...  
Keyword(s):  
High Temperature ◽  
Thermodynamic Assessment ◽  
Thermodynamic Description ◽  
Temperature Oxidation ◽  
Isothermal Sections ◽  
High Temperature Mechanical Properties ◽  
Formation Enthalpies ◽  
Calculation Results ◽  
Good Agreement ◽  
Fe Addition

Nb-Si based alloys have drawn continuously increasing attention due to their excellent high-temperature mechanical properties. The addition of element Fe could improve their poor high-temperature oxidation resistance which largely restricts their applications. With the aim to study the effect of Fe addition on the Nb-Si system and to design appropriate alloy composition, the Fe-Nb-Si ternary system has been thermodynamically investigated using the CALPHAD (CALculation of PHAse Diagrams) approach aided with the formation enthalpies for ternary compounds at 0 K computed via ab initio calculations. A self-consistent thermodynamic description of the Fe-Nb-Si system was obtained in this work. Key isothermal sections and liquidus projection were presented, and the calculation results show a good agreement with available experimental data.

scholarly journals Ultrafiltration concentration of whey in a pilot plant

2019 ◽  
Vol 81 (2) ◽  
pp. 41-46
Author(s):  
D. A. Rodionov ◽  
S. I. Lazarev ◽  
K. K. Polyansky ◽  
E. V. Eckert
Keyword(s):  
Experimental Data ◽  
Calculated Data ◽  
General View ◽  
Specific Flow ◽  
Milk Whey ◽  
Retention Coefficient ◽  
Tubular Type ◽  
Specific Output ◽  
Output Stream ◽  
Mathematical Expressions

Experimental data on the retention coefficient and the output specific flow are obtained. The test solutions were goat and cow's milk whey after obtaining cheese. The description, general view and technological scheme of a pilot installation of a tubular type are given. The studies were carried out on semipermeable tubular type ultrafiltration membranes manufactured by AO "ZAVKOM". Based on the studies, graphical dependences of the retention coefficient on the specific output stream were constructed and analyzed. During the analysis, it was noted that with an increase in the output specific flow of the solvent, the retention coefficient decreases. The reason for this is the boundary layers of fat and protein formed in the near-membrane layers, which prevents the passage of protein molecules through the pores of the membrane. Also during the experiment, it was noted that goat milk serum has a more oily structure and requires prior separation. For the theoretical calculation of the retention coefficient and specific output stream, mathematical expressions are developed and numerical values of the values of empirical coefficients are obtained. The developed mathematical expressions describe the experimental data with good confidence. The obtained experimental and calculated data can be used with great reliability in the calculations of mass-transported flows of substances through semipermeable membranes, as well as in engineering methods for calculating and predicting the effectiveness of the use of membrane processes for the concentration of whey.

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