Computational Thermodynamic Study to Predict Complex Phase Equilibria in the Nickel-Base Superalloy Rene
Computational Thermodynamic Study to Predict Complex Phase Equilibria in the Nickel-Base Superalloy Rene

Author: National Aeronautics and Space Adm Nasa

Publisher: Independently Published

Published: 2018-09-19

Total Pages: 48

ISBN-13: 9781723821837

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A previous study by Ritzert et al. on the formation and prediction of topologically closed packed (TCP) phases in the nickel-base superalloy Rene' N6 is re-examined with computational thermodynamics. The experimental data on phase distribution in forty-four alloys with a composition within the patent limits of the nickel-base superalloy Rene' N6 provide a good basis for comparison to and validation of a commercial nickel superalloy database used with ThermoCalc. Volume fraction of the phases and partitioning of the elements are determined for the forty-four alloys in this dataset. The baseline heat treatment of 400 h at 1366 K was used. This composition set is particularly interesting since small composition differences lead to dramatic changes in phase composition. In general the calculated values follow the experimental trends. However, the calculations indicated no TCP phase formation when the experimental measurements gave a volume percent of TCP phase less than 2 percent. When TCP phases were predicted, the calculations under-predict the volume percent of TCP phases by a factor of 2 to 8. The calculated compositions of the gamma and gamma' phases show fair agreement with the measurements. However, the calculated compositions of the P Phase do not agree with those measured. This may be due to inaccuracies in the model parameters for P phase and/or issues with the microprobe analyses of these phases. In addition, phase fraction diagrams and sigma and P phase solvus temperatures are calculated for each of the alloys. These calculations indicate that P phase is the primary TCP phase formed for the alloys considered here at 1366 K. Finally, a series of isopleths are calculated for each of the seven alloying elements. These show the effect of each alloying element on creating TCP phases.Copland, Evan H. and Jacobson, Nathan S. and Ritzert, Frank J.Glenn Research CenterTHERMODYNAMICS; COMPUTATION; EQUILIBRIUM; NICKEL ALLOYS; DATA BASES; TRENDS; PHASE DIAGRAMS; MICROAN

Statistical Thermodynamics of Alloys
Statistical Thermodynamics of Alloys

Author: N.A. Gokcen

Publisher: Springer Science & Business Media

Published: 2012-12-06

Total Pages: 330

ISBN-13: 1468450530

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This book is intended for scientists, researchers, and graduate students interested in solutions in general, and solutions of metals in particular. Readers are assumed to have a good background in thermodynamics, presented in such books as those cited at the end of Chapter 1, "Thermo dynamic Background." The contents of the book are limited to the solutions of metals + metals, and metals + metalloids, but the results are also appli cable to numerous other types of solutions encountered by metallurgists, materials scientists, geologists, ceramists, and chemists. Attempts have been made to cover each topic in depth with numerical examples whenever necessary. Chapter 2 presents phase equilibria and phase diagrams as related to the thermodynamics of solutions. The emphasis is on the binary diagrams since the ternary diagrams can be understood in terms of the binary diagrams coupled with the phase rule, and the Gibbs energies of mixing. The cal culation of thermodynamic properties from the phase diagrams is not emphasized because such a procedure generally yields mediocre results. Nevertheless, the reader can readily obtain thermodynamic data from phase diagrams by reversing the detailed process of calculation of phase diagrams from thermodynamic data. Empirical rules on phase stability are given in this chapter for a brief and clear understanding of the physical and atomistic factors underlying the alloy phase formation.

Computational Thermochemistry
Computational Thermochemistry

Author: Karl K. Irikura

Publisher:

Published: 1998

Total Pages: 488

ISBN-13:

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Comprises 20 contributions which grew from the August 1996 symposium. Representative paper topics include estimating phase- change enthalpies and entropies, electrostatic-covalent model parameters for molecular modeling, complete basis-set thermochemistry and kinetics, modeling free energies of solvation and transfer, use of density functional methods to compute heats of reaction, and a density functional study of periodic trends in bond energies. Together the contributions describe all the major methods used for estimating or predicting molecular thermochemistry. Appends information on software and databases for thermochemistry, essential statistical thermodynamics, and worked examples. Annotation copyrighted by Book News, Inc., Portland, OR

The SGTE Casebook
The SGTE Casebook

Author: Scientific Group Thermodata Europe

Publisher: CRC Press

Published: 1996

Total Pages: 236

ISBN-13:

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The Scientific Group Thermodata Europe (SGTE) is a consortium involved in the development and application of thermodynamic databanks for materials such as metals. Building on SGTE research, the second edition of this standard reference presents thermodynamic calculations as the basic tools in developing and optimizing various materials and processes. The SGTE Casebook: Thermodynamics at Work, Second Edition shows how this data can optimize the production and quality of steel and other alloys. The book explores phases stable at equilibrium as well as their amounts and compositions, and provides information about the degree of instability of the phases not present at equilibrium

Phase Equilibria, Phase Diagrams and Phase Transformations
Phase Equilibria, Phase Diagrams and Phase Transformations

Author: Mats Hillert

Publisher: Cambridge University Press

Published: 2007-11-22

Total Pages: 525

ISBN-13: 1139465864

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Computational tools allow material scientists to model and analyze increasingly complicated systems to appreciate material behavior. Accurate use and interpretation however, requires a strong understanding of the thermodynamic principles that underpin phase equilibrium, transformation and state. This fully revised and updated edition covers the fundamentals of thermodynamics, with a view to modern computer applications. The theoretical basis of chemical equilibria and chemical changes is covered with an emphasis on the properties of phase diagrams. Starting with the basic principles, discussion moves to systems involving multiple phases. New chapters cover irreversible thermodynamics, extremum principles, and the thermodynamics of surfaces and interfaces. Theoretical descriptions of equilibrium conditions, the state of systems at equilibrium and the changes as equilibrium is reached, are all demonstrated graphically. With illustrative examples - many computer calculated - and worked examples, this textbook is an valuable resource for advanced undergraduates and graduate students in materials science and engineering.

Phase Equilibria, Crystallographic and Thermodynamic Data of Binary Alloys
Phase Equilibria, Crystallographic and Thermodynamic Data of Binary Alloys

Author: Felicitas Predel

Publisher: Springer

Published: 2016-11-03

Total Pages: 254

ISBN-13: 9783642249761

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Thermodynamics determines the properties and region of existence of any alloy. Pressure, temperature and composition are the key parameters that dictate its crystal structure, crystallographic data, physical and mechanical properties. Phase diagrams are of utmost importance as overviews of the particularities of any alloying mixture. The present volume presents phase equilibria, thermodynamic and crystallographic data of the binary alloys K-O ... Y-Zr.