Degree Type
Dissertation
Date of Award
1987
Degree Name
Doctor of Philosophy
Department
Materials Science and Engineering
First Advisor
John F. Smith
Abstract
A calculation of the Fe-Th phase relationships was undertaken in order to develop a self-consistent description of the system. A subregular solution model was used to describe the solution behavior. Intermediate phases were treated as composition invariant. Due to the limited availability of experimental thermodynamic data, a multi-step analysis was employed to develop a better description of the thermodynamic properties in the system;As a quantitative guide to the glass forming ability (GFA) in the Fe-Th system, T[subscript]0 and TTT curves were evaluated from the previously derived thermodynamic description of the system. From the TTT curves, critical cooling rates (R[subscript] c) to avoid crystallization were determined. Since the Fe-Th system has several solid phases, the relative stability of each phase in the metastable region is discussed. Kinetic parameters such as viscosity ([eta]), glass transition temperature (T[subscript] g) and interfacial energy ([sigma]) were estimated since experimental values were not available;This analysis indicates that thermodynamic data alone can not be relied upon to predict the phase boundary behavior. Both thermodynamic data and phase diagram data should be used.
DOI
https://doi.org/10.31274/rtd-180813-11068
Publisher
Digital Repository @ Iowa State University, http://lib.dr.iastate.edu/
Copyright Owner
Kyung Jong Lee
Copyright Date
1987
Language
en
Proquest ID
AAI8805104
File Format
application/pdf
File Size
80 pages
Recommended Citation
Lee, Kyung Jong, "Thermodynamic evaluation of the Fe-Th system and glass forming ability in the Fe-Th system " (1987). Retrospective Theses and Dissertations. 8674.
https://lib.dr.iastate.edu/rtd/8674
