CAREER: Understanding Interface-Mediated Deformation in Layered Composites through Modeling and Experiment

金属纳米复合材料是一类特殊的金属复合材料，具有超细的层厚，具有独特的性能。与大型散装成分相比，它们表现出强度的大幅增加。在某些情况下，它们显示出更高的延展性，高辐射损伤耐受性，抗震性和热稳定性；从而在各个领域显示出巨大的应用潜力。这些材料可以带来新的性能水平和能源效率，这是现有材料无法实现的，因此可以产生重大的经济影响。然而，缺乏对控制金属纳米层状复合材料性能的潜在机制的理解严重限制了我们目前加工和定制它们的能力。该学院早期职业发展（Career）奖支持基础研究，以推进基础知识，开发计算工具，并为具有特殊可控性能的金属纳米层复合材料提供设计指南。这项研究的结果有可能提高美国在航空航天和电子设备市场上的竞争力。作为该项目的一部分，研究结果将通过出版物和积极参加会议和讲习班向其他研究人员和一般公众提供。为了培养21世纪的劳动力，这项工作还通过外展计划增加了高中生对科学和技术概念的接触，并为学生研究人员与国家实验室合作提供了宝贵的教育机会。本研究旨在开发一种新的实验验证的多尺度建模方法来阐明金属纳米层复合材料的力学性能和变形机制。具体的研究目标是：(i)探索位错-界面相互作用对金属纳米层复合材料强度的影响；（ii）研究界面结构和层厚对延性和塑性失稳的影响；（iii）确定组分的界面结构和材料性能在累积辊接过程织构演变中的作用；（四）揭示金属纳米层复合材料循环变形行为的微观机制。研究结果将为位错与界面之间的相互作用及其与宏观应用领域的相互作用提供见解。多尺度建模方法和实验研究的无缝集成将允许在纳米结构材料的基本缺陷模型和变形实验之间进行一对一的比较，为测试最先进的晶体缺陷理论在真实材料系统中的适用性创造一个独特的机会。

Metallic nanolayered composites are a special class of metallic composite materials with ultra-fine layer thicknesses which impart unique behavior. They exhibit large increases in strength compared to larger-scale bulk constituents. In some cases, they display increased ductility, high radiation damage tolerance, shock resistance, and thermal stability; thus showing great potential for applications in a variety of fields. These materials can lead to new performance levels and energy efficiency not achievable with current materials and thus can have a significant economic impact. However, a lack of understanding of the underlying mechanisms that control the properties of metallic nano layered composites severely limits our current ability to process and tailor them. This Faculty Early Career Development (CAREER) award supports fundamental research to advance fundamental knowledge, develop computational tools and provide design guidelines for metallic nanolayered composites with exceptional controllable properties. Results from this research have the potential to enhance U.S. competitiveness within the markets of aerospace and electronic devices. As part of this project, the research results will be made available to other researchers and the general public through publications and active participation in conferences and workshops. With the aim of educating the twenty-first century workforce, this work also increases the exposure of high school students to science and technology concepts through outreach programs, and provides invaluable educational opportunities for student researchers to collaborate with National Laboratories.This research is to develop a new experimentally-validated multiscale-modeling approach to elucidate the mechanical properties and deformation mechanisms of metallic nanolayered composites. The specific research objectives are: (i) to explore the influence of dislocation-interface interactions on the strength of metallic nanolayered composites; (ii) to investigate the effects of the interface structure and layer thickness on the ductility and plastic instability; (iii) to identify the roles of interface structure and material properties of constituents in the texture evolution during the accumulative roll bonding process; (iv) to reveal the microscopic mechanisms for cyclic deformation behavior of metallic nanolayered composites. The research results will provide insights into the interaction between dislocations and interfaces and their interplay with macroscopically applied fields. The seamless integration of the multiscale-modeling approach and experiment studies will allow one-to-one comparisons between fundamental defect models and deformation experiments on nanostructured materials, creating a unique opportunity for testing the applicability of state-of-the-art theories of crystal defects in real materials systems.