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Structural and thermophysical property studies of metallic liquids and glasses using the beamline electrostatic levitation technique

Posted on:2012-10-25Degree:Ph.DType:Dissertation
University:Washington University in St. LouisCandidate:Mauro, Nicholas AnthonyFull Text:PDF
GTID:1451390008992635Subject:Physics
Abstract/Summary:
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 Zr 80Pt20 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.
Keywords/Search Tags:Atomic structures, Glass, Structural, Thermophysical, Metallic, Liquids, Using
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