Date of Award

Summer 8-15-2015

Author's School

Graduate School of Arts and Sciences

Author's Department

Physics

Degree Name

Doctor of Philosophy (PhD)

Degree Type

Dissertation

Abstract

Metallic glasses (and glasses in general) offer unique material properties compared to their crystalline counterparts. Yet the physics of the glass transition remain poorly understood. By examining the evolution of properties in the liquid as it is cooled toward the glass transition we hope to discern how they relate to glass formation.

Of particular interest is the concept of kinetic fragility, first defined in terms of the viscosity behavior near the glass transition, and what it means for a high temperature liquid to be “fragile” or “strong.” This dissertation presents several studies of metallic liquids using the electrostatic levitation technique. A method for determining the evaporation rate of samples is developed, an important factor for consideration in many experiments and industrial applications. It may also yield further insights when coupled with surface tension measurements, a technique for which is also developed here, with encouraging preliminary results. A method of extracting additional structural information from X-ray diffraction on a related set of alloys is presented and applied to liquid Cu-Zr alloys; this is the first time to this author’s knowledge that this technique has been applied to liquids. The high-temperature viscosity of a large set of alloys is measured and it is found that they obey a simple universal curve with only two parameters. These parameters are closely related to fundamental properties of the liquid, the infinite temperature viscosity limit and the glass transition temperature. The relationship of glass-formability to kinetic and thermodynamic properties is examined in CuZrAl alloys. The existence of a structural crossover temperature is examined in the Vit106 alloy and microgravity experiment designs are presented for upcoming experiments on the International Space Station. Finally, a new procedure for acquiring and analyzing surface tension data with the oscillating drop method is developed to account for the effect of sample rotation, with results presented for a variety of samples, creating intriguing possibilities for future research.

Language

English (en)

Chair and Committee

Kenneth F Kelton

Committee Members

Katharine M Flores, Patrick C Gibbons, Zohar Nussinov, Li Yang,

Comments

Permanent URL: https://doi.org/10.7936/K7QF8R28

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