CAREER: An Elastic Approach to Strong Glasses

非技术描述：随着个人电子产品、汽车、太阳能电池板、建筑和海底通信电缆等应用对轻质和耐用玻璃的需求不断增加，寻找高强度玻璃是当今最重要的兴趣。这个项目的目的是通过研究玻璃对外部刺激(如温度和压力)的弹性反应，并辅之以计算机模拟，来促进对玻璃微观结构的基础知识。对玻璃结构的基本了解可以使玻璃的预测性设计具有量身定做的性能和在能源消耗和可持续性方面的相关好处。综合教育计划将通过以下方式解决计算材料科学课程的发展：1)将本科水平的计算材料科学课程引入材料科学与工程课程；2)将计算模块纳入核心材料科学课程。在实施这一项目时，对研究生和本科生进行玻璃研究前沿领域的培训。正在继续努力，通过激发年轻人的好奇心，并向妇女和代表性不足的少数族裔灌输信心，激励和鼓励K-12年级的学生将科学和工程作为职业道路。技术细节：对玻璃原子结构的准确了解对于推动未来玻璃科学和技术的突破至关重要。然而，尽管进行了广泛的研究，但在原子水平上表征玻璃的无序结构仍然是一个巨大的挑战。该项目通过探测/扰动玻璃结构来解决这个长期存在的问题，热或机械搅拌会导致玻璃结构的弹性模数发生变化。在外部刺激下的这种变化不可避免地反映了潜在的结构反应，以及结构本身。这是因为弹性模数与原子排列和原子间相互作用密切相关，体现了微观结构和成键信息，定义简单，宏观上易于测量。对玻璃中结构-弹性模关系的基本理解可能有助于我们理解最近在氧化物和金属玻璃中观察到的一个显著的经验关联：即断裂能随着泊松比的增加而增加，在临界泊松比为0.31-0.32时发生急剧的脆-韧转变。同时，泊松比与断裂能之间的相关性可以作为寻找强玻璃的指南。利用高温、高压、高应变条件下的原位拉曼和布里渊光散射技术，辅以预测计算方法，完成了本课题的研究目标。

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.