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

技术概述：晶界工程(GBE)领域已经展示了具有低西格玛(西格玛小于或等于29)晶界的许多优点，以提高材料的物理和化学性能。对纳米尺度孪晶界的研究允许通过在纳米尺度上控制和操纵颗粒和边界来进行下一阶段的微结构材料设计。因此，这一建议的研究目标有两个：a)通过研究在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级生长孪晶的演化；b)描述生长孪晶如何与晶界相互作用以产生低西格玛晶界。为了完成设定的目标，本项目将重点研究一些关键方面，如生长孪晶的演化，以提供一个框架，通过一种受控的合成方法：磁控溅射，在许多不同的系统中引入纳米级生长孪晶。非技术总结：本研究通过引入利用传统材料科学和纳米技术的工程结构，为材料开发提供了一个新的方向。尽管纳米材料已经显示出巨大的潜力，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有望进一步改进纳米结构材料的领域提供基础研究。这种能力可以进一步帮助设计新的耐热涂层以及微米和纳米级的MEMS系统。此外，该项目侧重于科学、技术、工程和数学(STEM)学习，因为PI将与非营利性教育组织虹彩合作，提供高质量、令人兴奋的现实世界科学教育，目标是洛杉矶地区的低收入西班牙裔和非裔美国儿童。南加州大学PI的工程新生学院班将为彩虹计划开发一个为期十节的绿色材料加工研讨会。因此，研究、教学和推广被无缝地结合在一起，成为国际和平倡议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.