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

Phase Equilibrium Engineering
Phase Equilibrium Engineering

Author: Esteban Alberto Brignole

Publisher: Elsevier

Published: 2023-10-01

Total Pages: 0

ISBN-13: 9780443158575

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Phase Equilibrium Engineering, Second Edition presents a systematic and fully updated study of the application of phase equilibrium tools to the development of chemical processes. The thermodynamic modeling of mixtures for process development, synthesis, simulation, design, and optimization are analyzed. This book changes the focus from the use of thermodynamics relationships to compute phase equilibria to the design and control of the phase conditions that a process needs. In this second edition, the authors have thoroughly updated all chapters with new sections and case studies and added new chapters relating to their expertise and newest experimental work in high pressure labs and modelling of behavior of complex mixtures. Traditionally, the teaching of phase equilibria emphasizes the relationships between the thermodynamic variables of each phase in equilibrium rather than its engineering applications. This book changes the focus from the use of thermodynamics relationships to compute phase equilibria to the design and control of the phase conditions that a process needs. The thermodynamic modeling of mixtures for process development, synthesis, simulation, design, and optimization is analyzed. The relation between the mixture molecular properties, the selection of the thermodynamic model and the process technology that could be applied are discussed. A classification of mixtures, separation process, thermodynamic models and technologies is presented to guide the engineer in the world of separation processes. The phase condition required for a given reacting system is studied at subcritical and supercritical conditions. The four cardinal points of phase equilibrium engineering are: the chemical plant or process, the laboratory, the modeling of phase equilibria and the simulator. The harmonization of all these components to obtain a better design or operation is the goal of phase equilibrium engineering.

The Superalloys
The Superalloys

Author: Roger C. Reed

Publisher: Cambridge University Press

Published: 2008-07-31

Total Pages: 363

ISBN-13: 1139458639

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Superalloys are unique high-temperature materials used in gas turbine engines, which display excellent resistance to mechanical and chemical degradation. This book introduces the metallurgical principles which have guided their development. Suitable for graduate students and researchers, it includes exercises and additional resources at www.cambridge.org/9780521859042.