Nanomechanics of Tough Nanostructured Metals

纳米结构的金属，具有通常小于100 nm的微观结构长度尺度，近年来一直是大量研究的主题。它们在结构上的特征在于大量的内部界面，如晶界或孪晶界，与粗晶粒对应物相比，这可能会显着改变它们的物理，机械和化学性质。在典型的纳米结构金属中，强度和延展性之间往往存在令人遗憾的权衡。纳米晶金属通常表现出比传统粗晶金属高五倍的强度。但它们的延展性往往很差，从而限制了它们的结构甚至功能应用。该研究的目标是开发一个强大的建模和实验框架，用于设计具有高强度和高延展性的坚韧纳米结构材料。以纳米结构铜为模型系统，进行紧密耦合的建模和实验研究，以阐明控制纳米结构金属延展性的活性机制，并开发新的加工方法来生产坚韧纳米结构材料。 这项研究将通过对纳米结构金属中信息机制的理解的根本性进步来实现更广泛的影响。拟议的研究是必要的第一步，工程坚韧的纳米结构材料，可能会导致显着的重量和能源节省在微系统的应用。 新的变形机制和纳米结构材料的加工技术的知识将被整合到高年级本科课程。少数民族大学生将被招募参加该项目的夏季研究。我们提供这些机会，以激发他们在纳米科学和纳米技术领域从事职业的兴趣。

Nanostructured metals, with microstructural length scales typically smaller than 100 nm, have been the subject of considerable research in recent years. They are structurally characterized by a large number of internal interfaces such as grain boundaries or twin boundaries, which may significantly change their physical, mechanical, and chemical properties compared to the coarse-grained counterparts. In typical nanostructured metals, there is often a regrettable trade-off between strength and ductility. Nanocrystalline metals routinely exhibit up to five times higher strength than conventional coarse-grain metals. But their ductilities are often poor, thus limiting their structural and even functional applications. The goal of the proposed research is to develop a robust modeling and experimental framework for the design of tough nanostructured materials of ultrahigh strength and high ductility. Taking the nanostructured copper as a model system, a tightly coupled modeling and experimental study will be performed to elucidate the active mechanisms controlling ductility in nanostructured metals, and to develop novel processing methods for producing tough nanostructured materials. This research will achieve a broader impact through a fundamental advancement in the understanding of information mechanisms in nanostructured metals. The proposed research is the necessary first step toward engineering tough nanostructured materials which may lead to significant weight and energy savings in applications of microsystems. The knowledge of novel deformation mechanisms and processing techniques of nanostructured materials will be integrated into the senior undergraduate course. Minority undergraduates will be recruited for summer research on this project. We offer these opportunities to inspire their interests in pursuing the career in the area of nanoscience and nanotechnology.