CAREER: Exploring Nanoscale Growth Twins for the Development of Grain Boundary Engineering at the Nanoscale

技术概述：晶界工程（GBE）领域已经证明了低西格玛的许多优点；（σ小于或等于29）晶界，以提高材料的物理和化学性能。纳米尺度孪晶界的研究为下一阶段的微结构材料设计提供了条件，即在纳米尺度上对晶粒和晶界进行控制和操作。因此，本课题的研究目的是双重的：a)通过研究不同工艺条件下形成的缺陷及其与孪晶形成的关系来了解纳米尺度生长孪晶的演化；b)研究生长孪晶如何与晶界相互作用以产生低西格玛晶界。为了完成既定的目标，本项目将重点关注一些关键方面，如生长孪晶的演变，为使用可控合成方法：磁控溅射在许多不同系统中引入纳米级生长孪晶提供框架。非技术概述：本研究通过引入传统材料科学和纳米技术的工程结构，为材料的发展提供了新的方向。尽管纳米材料显示出巨大的潜力，但它们的应用通常有两个限制因素：热稳定性和低延展性。这项研究计划旨在为纳米结构材料的进一步改进提供基础研究。这种能力可以进一步帮助设计新的耐热涂层和微纳米级MEMS系统。此外，由于PI将与非营利教育组织彩虹合作，该项目将重点关注科学、技术、工程和数学（STEM）学习，为洛杉矶地区低收入的西班牙裔和非裔美国儿童提供高质量、令人兴奋的真实科学教育。彩虹项目将由南加州大学PI的工程新生学院班级举办一个关于绿色材料加工的十期研讨会。因此，研究、教学和外展被无缝地结合在一起，成为PI更广泛影响的一部分。

TECHNICAL SUMMARY: The field of grain boundary engineering (GBE) has demonstrated the many advantages of having low Sigma; (Sigma less than or equal to 29) grain boundaries for enhanced physical and chemical performance of materials. The study of nanoscale twin boundaries allows for the next stage of microstructural material design by the control and manipulation of both grains and boundaries at the nanoscale. Therefore, the research objective of this proposal is twofold: a) to understand the evolution of nanoscale growth twins by studying the defects formed under various processing conditions and their relationship to twin formation and b) to relate how growth twins interact with boundaries to generate low Sigma grain boundaries. In order to accomplish the set objectives this project will focus on some key aspects such as the evolution of growth twins to provide a framework for the introduction of nanoscale growth twins in many different systems by using a controlled synthesis method: magnetron sputtering.NON-TECHNICAL SUMMARY: This study presents a new direction for materials development by introducing engineered structures using traditional materials science and nanotechnology. Even though nanoscale materials have shown tremendous potential there are typically two limiting factors to their application: thermal stability and low ductility. This research proposal aims to provide fundamental research on an area that promises further improvement of nanostructured materials. This ability can further aid in the design of new thermal resistant coatings and micro- and nano-scale MEMS systems. In addition, this projects focuses on Science, Technology, Engineering and Math (STEM) learning since the PI will work with Iridescent, a non-profit, educational organization, to provide high quality, exciting, real-world science education that targets low-income Hispanic and African-American children in the Los Angeles area. A ten-session workshop on green materials processing will be developed for the Iridescent program by the PI's Engineering Freshman Academy class at USC. Thus, research, teaching and outreach are seamlessly combined as part of the PI's broader impacts.