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http://hdl.handle.net/11375/13010
Title: | The Structural Disjoining Potential of Grain Boundary Premelting in Binary Alloys using Phase Field Crystal Model |
Authors: | Rowan, Elizabeth |
Advisor: | Provatas, Nikolas Hoyt, Jeffrey Zurob, Hatem |
Department: | Materials Science |
Keywords: | premelting;disjoining potential;alloy;grain boundary;phase-field crystal;Structural Materials;Structural Materials |
Publication Date: | Oct-2013 |
Abstract: | <p>A framework is described using the phase-field crystal model for the study of premelting in binary alloys through short-range interfacial interactions that arise from the structure of grain boundaries. A nonconserved model A formulation of PFC was used to model grain boundaries in two dimensions for several different angles of misorientation: 27.8, 21.8, 17.8, 13.2, and 5 degrees. The character of the premelting transition, whereby a liquid-like film develops at a defect at temperatures below the melting point, changed with misorientation angle. An excess mass over the grain boundary can be defined as an analog to the liquid layer thickness due to premelting. It is found that low-angle grain boundaries remain at a relatively constant value of excess mass, and indeed can remain solid above the melting point. High-angle grain boundaries have a logarithmically increasing width that diverges at the melting point. A width-dependent energy can be defined called the disjoining potential that takes into account structure, interfacial and bulk energies to describe the liquid-layer width. The form of this disjoinging potential was found to be exponential and monotonically decreased as width increased for high angles and produced an attractive minimum for low angles. The results of this work were compared to a pure material from a previous study.</p> |
URI: | http://hdl.handle.net/11375/13010 |
Identifier: | opendissertations/7846 8904 4173972 |
Appears in Collections: | Open Access Dissertations and Theses |
Files in This Item:
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fulltext.pdf | 5.37 MB | Adobe PDF | View/Open |
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