Author's School

Graduate School of Arts & Sciences

Author's Department/Program

Physics

Language

English (en)

Date of Award

January 2011

Degree Type

Dissertation

Degree Name

Doctor of Philosophy (PhD)

Chair and Committee

Kenneth Kelton

Abstract

An accurate description of atomic structures is at the heart of an improved understanding of the properties of condensed solids. By correlating structural information from high energy synchrotron X-ray diffraction with thermophysical properties important insights have been gained into the role of local structural evolution in undercooling and glass formation. Here, the results of a number of investigations into the structures and properties of some amorphous phases will be presented and analyzed. Phase separation in Al88Y7Fe5 is identified prior to devitrification and is proposed as an explanation for extremely high observed nucleation rates. The development and construction of the Beamline Electrostatic Levitation Technique: BESL), which has shown increased utility over the past several years as an important probe of metallic systems, will be presented. Using BESL, atomic structures in equilibrium and supercooled liquids of Zr80Pt20 are explored using Reverse Monte Carlo methods, which indicate the presence of medium range atomic order that is dominated by Pt-Pt correlations. The thermophysical properties and atomic structures in the bulk metallic glass forming Ni-Nb and Ni-Nb-Ta liquids are examined. The high glass formability and low glass formability compositions are compared and important differences are discussed. Finally, the X-ray structure factors and densities for liquid aluminum from 1123K to 1273K are presented and atomic structures as a function of temperature have been constructed from the diffraction data with Reverse Monte Carlo fits.

Comments

Permanent URL: http://dx.doi.org/10.7936/K7C53HZ8

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