CAREER: An Elastic Approach to Strong Glasses

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NON-TECHNICAL DESCRIPTION: The search for strong glasses is of paramount interest today with the increasing demand for light-weight and durable glasses for applications such as personal electronics, automobiles, solar panels, buildings, and submarine communications cables. This project aims to advance fundamental knowledge of the microscopic structure of glass by studying its elastic response to external stimuli such as temperature and pressure in experiments complemented by computer simulations. A fundamental understanding of glass structure may enable predictive design of glasses with tailor-made properties and related benefits with respect to energy consumption and sustainability. The integrated educational plan is to address the computational materials science curriculum development by: 1) introducing an undergraduate level computational materials science course into the Materials Science and Engineering curriculum; and 2) incorporating computational modules into core materials science classes. In carrying out this project, graduate and undergraduate students are trained in frontier areas of glass research. Continuous efforts are being made to inspire and encourage K-12 students to pursue science and engineering as a career path, by igniting curiosity in young minds and instilling confidence in women and underrepresented minorities. TECHNICAL DETAILS: An accurate knowledge of the atomic structure of glass is critical for enabling future breakthroughs in glass science and technology. However, despite extensive research, characterizing the disordered structure of glass at the atomic level remains a grand challenge. This project tackles the longstanding problem by probing/perturbing the glass structure with thermal or mechanical agitations, which leads to variations in its elastic moduli. Such changes under external stimuli inevitably reflect the underlying structural response, and the structure itself. This response occurs because elastic moduli, simple to define and easy to measure macroscopically, are closely related to the atomic arrangements and the interatomic interactions, embodying the microscopic structure and bonding information. The fundamental understanding of the structure-elastic moduli relation in glass may help us to understand a striking empirical correlation observed recently in oxide and metallic glasses: namely that the fracture energy increases with the Poisson's ratio, with a sharp brittle-to-ductile transition at a critical Poisson's ratio of 0.31-0.32. At the same time, the correlation between Poisson's ratio and fracture energy can serve as a guide to search for strong glasses. In situ Raman and Brillouin light scattering techniques under high temperature, high pressure and high strain conditions, complemented by predictive computational methods, are used to accomplish the research goals of this project.