CAREER: Robust Thin Film Shape Memory Alloys for Microelectromechanical Systems (MEMS)

耶鲁大学的这项职业奖是研究形状记忆合金（如NiTi），它具有加热时“记住”其原始形状的独特能力，可用作微机电系统（MEMS）的薄膜致动器。 在MEMS中的驱动模式中，形状记忆合金产生最大的驱动力，并且将有益于诸如微阀、微泵和微操纵器的应用。尽管有这些潜在的用途，但形状记忆合金在MEMS中的集成是有限的，因为它们的行为受到急性成分敏感性的困扰。 此外，它们的薄膜机械行为的细节（通常与体相背离）在很大程度上仍未得到探索。 该奖项将研究合金化对相变温度，滞后行为，微观结构，致动性能和机械性能的影响。 此外，该奖项还将探索薄膜NiTi形状记忆材料的行为;改善其与MEMS工艺的集成;并通过检查表现出弹性非线性的材料来拓宽对薄膜机械性能的理解。 结构与性能的关系将通过观察形状记忆合金的微观结构与电子显微镜;驱动性能与MEMS悬臂梁;和相变温度行为与差示扫描量热法和晶片曲率技术进行检查。 与工业界、合作大学和布鲁克海文国家实验室（BNL）的拟议合作将提供对薄膜形状记忆合金特性及其应用的基本理解。 形状记忆合金和MEMS也提供了一个重要的教育平台，因为它们对学生和非专业观众都很有吸引力。除了这项研究之外，还将开发一个新的本科MEMS课程以及一个推广计划，鼓励学生通过动手活动探索科学。一系列展示不同科学家和有趣的科学活动的讲座将鼓励所有学生，特别是妇女和少数民族学生，考虑科学。其他教育机制包括基于网络的演示网站，科普写作，以及与国家科学资源中心（史密森学会和国家科学院的一个分支）的合作。

This Career award to Yale University is to study shape memory alloys (such as NiTi), which have the unique ability of "remembering" their original shape when heated and can be used as thin film actuators for microelectromechanical systems (MEMS). Among the actuation modes in MEMS, shape memory alloys produce the largest actuation force and will benefit applications such as microvalves, micropumps, and micromanipulators. Despite these potential uses, integration of shape memory alloys in MEMS is limited, because their behavior is plagued with an acute compositional sensitivity. In addition, details of their thin film mechanical behavior, which often departs from bulk, remains largely unexplored. This award will study the affects of alloying on phase transformation temperature, hysteresis behavior, microstructure, actuation properties, and mechanical properties. In addition, the award will explore the behavior of thin film NiTi shape memory materials; improve their integration into the MEMS process; and broaden the understanding of thin film mechanical properties, by examining materials that exhibit elastic non-linearities. Structure-property relationship will be examined by observing the microstructure of shape memory alloys with electron microscopy; actuation properties with MEMS cantilevers; and transformation temperature behavior with differential scanning calorimetry and wafer curvature techniques. Proposed collaborations with industry, partner universities, and Brookhaven National Labs (BNL) would provide the fundamental understanding the properties of thin film shape memory alloys and their applications. Shape memory alloys and MEMS also provide a significant educational platform for they are compelling to both students and lay audiences. In addition to this research, a new undergraduate MEMS class will be developed as well as an outreach program that will encourage students to explore science through hands-on activities. A lecture series that showcases diverse scientists and fun science events will encourage all students, particularly women and minority students, to consider science. Other educational mechanisms include a web-based demonstration site, popular science writing, and collaborations with the National Science Resource Center (an arm of the Smithsonian Institute and the National Academies).