Collaborative Research: Fracture Mechanics of Glasses with Nanoscale Phase Separation - A Multiscale Experimental and Computational Study

尽管玻璃具有高强度、高透明度等独特性能，但其固有的脆性严重限制了其在许多实际应用中的应用。外部处理可以增加玻璃的韧性，但通常会损害其光学透明度。作为另一种途径，该奖项支持基础研究，以阐明如何使用受控纳米成分来增强玻璃的抗裂性。这一知识将加速设计坚固而透明的玻璃。这项研究的见解将促进玻璃作为一种具有竞争力的材料在更广泛的应用中使用，由于玻璃破裂的风险导致的安全和可靠性方面的担忧，到目前为止还没有考虑在这些应用中使用玻璃。来自该项目的见解还将改善许多现有应用中的玻璃性能，例如，较轻的汽车挡风玻璃将显著节省能源。因此，这项研究不仅将促进科学的进步，而且由于玻璃的普及也将促进国民的健康、繁荣和福利。通过整合多个学科，包括物理、材料科学和机械工程，这项研究将在工程的各个方面培养不同的学生群体，并有助于形成美国玻璃行业在全球竞争中迫切需要的下一代科学家。此外，该奖项还将支持：将本科生纳入研究，通过与玻璃制造商康宁公司的广泛合作，将研究与教育相结合，以及招募少数族裔学生，并通过大学项目向K-12学生推广脆性仍然是眼镜的主要缺点。为了克服这一古老的局限性，本研究旨在阐明纳米尺度的非均质性和可控相分离对钙铝硅酸盐玻璃断裂韧性的影响，钙铝硅酸盐玻璃是无碱显示玻璃的典型模型。自下而上的策略依赖于高通量的分子动力学模拟，受益于拓扑约束理论，并在动态模拟中达到顶峰，以确保所有考虑的空间尺度：原子、微结构和连续体的握手。这些预测得到了包括结构分析和力学试验在内的试验的系统验证。这一跨学科的努力将为玻璃中相分离的热力学和动力学提供一些新的见解。这一新的基础知识将作为指南，阐明原子拓扑结构、其异质性和纳米级相分离在控制硅酸盐玻璃的纳米延展性和宏观韧性方面的独特作用。该奖项反映了NSF的法定使命，并通过使用基金会的智力优势和更广泛的影响审查标准进行评估，被认为值得支持。

Although glasses exhibit unique properties, such as high strength and transparency, their inherent brittleness seriously limits their use in many practical applications. Extrinsic treatments can increase the toughness of glass but typically compromise its optical transparency. As an alternative route, this award supports fundamental research to elucidate how controlled nanoscale composition may be used to enhance the resistance to fracture of glass. This knowledge will accelerate the design of tough, yet transparent glasses. Insights from this study will promote glass as a competitive material for a broader range of applications, for which glasses have not been considered until now due to concerns related to safety and reliability resulting from their risk of fracture. Insights from this project will also lead to improved glass performance in many existing applications,for instance, lighter automotive windshields would result in significant energy savings. Thus, the research will not only promote the progress of science but due to the prevalence of glass will also advance the national health, prosperity, and welfare. By integrating multiple disciplines, including physics, material science, and mechanical engineering, this research will train a diverse group of students in various aspects of engineering and contribute to forming the next generation of scientists that the U.S. glass industry critically needs to compete globally. In addition, this award will support: inclusion of undergraduate students in research, integration of research and education through extensive collaboration with glass manufacturer Corning Inc., and recruitment of minority students and outreach to K-12 students through university programs Brittleness remains the main drawback of glasses. To overcome this age-old limitation, this research aims to elucidate the effects of nanoscale heterogeneities and controlled phase separation on the fracture toughness of calcium aluminosilicate glasses,an archetypical model for alkali-free display glasses. The bottom-up strategy relies on high-throughput molecular dynamics simulations, benefits from topological constraint theory, and culminates in peridynamic simulations to ensure the hand-shake of all the considered spatial scales: atoms, microstructure, and continuum. These predictions are systemically validated by experiments, which comprise structural analysis and mechanical tests. This interdisciplinary effort will offer some new insights in the thermodynamics and kinetics of phase separation in glasses. This new fundamental knowledge will serve as a guide to elucidate the distinct roles of the atomic topology, heterogeneity thereof, and nanoscale phase separation in controlling the nanoductility and macroscopic toughness of silicate glasses.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.