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A MD STUDY OF Sn AND ITS CRYSTAL - MELT INTERFACE PROPERTIES

<p>The unique combination of material properties has led to the extensive use of Sn 111 a wide range of industrial applications, making it one of the most important commercial materials. In this research work, an atomic scale computational model has been developed for Sn using Molecular Dynamics (MD). The MD simulation technique has proven to be quite effective in establishing quantitative models for different materials. But accurately modeling Sn using classical interatomic potentials in MD is quite difficult due to its complex crystal structure and phase stability. The Modified Embedded Atom Method (MEAM) has been used in this study as it includes angular forces present in materials with directional bonding, which can model both the metallic and covalent phase of Sn. Using this method, a previously published pure Sn potential has been modified to improve upon the melting properties. Some predictions are presented for thermodynamic quantities, phase stability, structural properties and elastic constants. Good agreement has been found with experiments for the melting point, the phase transition temperature and the latent heats; however the predicted elastic constants are somewhat greater than those found in the literature. The crystal - melt interface and its properties are also investigated with the new potential. The (001)[100] orientation of the interface is found to be atomically rough. Capillary Fluctuation Method (CFM) is used to compute the crystal - melt interface stiffness in this orientation and the interface kinetics is investigated with CFM and Free Solidification (FS) technique. The (100)[010] and (110)[1Ī0] oriented interface is found to be flat or atomically smooth. Wulff plot is constructed to determine the equilibrium shape of a single Sn crystal and an approximate measurement of the interfacial energy for the flat interfaces is presented.</p> / Master of Applied Science (MASc)

Identiferoai:union.ndltd.org:mcmaster.ca/oai:macsphere.mcmaster.ca:11375/9486
Date09 1900
CreatorsYasmin, Shaon
ContributorsHoyt, Jeffrey J., Materials Science and Engineering
Source SetsMcMaster University
Detected LanguageEnglish
Typethesis

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