In-situ micro-Brillouin spectroscopy study of calcium aluminoborosilicate glasses under vickers indentation

Authors
Oistad, Brian
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Other Contributors
Huang, Liping
Shi, Yunfeng
Tomozawa, Minoru
Issue Date
2020-12
Keywords
Materials engineering
Degree
MS
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This electronic version is a licensed copy owned by Rensselaer Polytechnic Institute, Troy, NY. Copyright of original work retained by author.
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Abstract
Oxide glass has held a critical role in science and technology despite a continuously evolving market; today its importance in display technologies for consumer electronics and automotive fields, as well as optical fibers for high-speed communication cannot be understated. To maintain and proliferate glass as a material solution to new engineering challenges, we must first build a robust understanding of ways to mediate glass’ obvious shortcomings (e.g., brittleness). As it stands today, however, there are significant gaps in our knowledge of how glass responds in the instant that a mechanically damaging event occurs, such as dropping a cellular phone screen against a sharp surface or a stone striking a windshield. Knowledge of glass structure-property relationships, especially regarding glass failure from mechanical stimuli, would help accelerate glass prototyping and enable us to create what is referred as ‘designer glass’, which is made special to the demands of the consumer.This thesis work demonstrated the practicality of utilizing micro-Brillouin spectroscopy to map the stress distributions in glass in-situ under sharp contact loading. A high-intensity laser was used as the probing light source and coupled with an inverted Vickers indenter, to collect Brillouin spectra as a function of spatial position. Regions under compressive and tensile stress, and the boundary between them, were for the first time observed in glass in-situ under indentation. Boron content was varied in the samples to illustrate the differences in mechanical response of glass to indentation. It was found that a higher content of trigonal boron increases the sample’s propensity to densify and reduces the tensile stress build-up that is responsible for the sub-surface crack nucleation, thus increasing the crack resistance of glass.
Description
December 2020
School of Engineering
Department
Dept. of Materials Science and Engineering
Publisher
Rensselaer Polytechnic Institute, Troy, NY
Relationships
Rensselaer Theses and Dissertations Online Collection
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