GOALI: Development of Metallic MEMS Materials for Extreme Environments

非技术概述：在过去的几十年里，微型设备和微电子机械系统(MEMS)已被用作喷墨打印机、加速计、陀螺仪、压力传感器和数字投影仪，并已成为一个价值数十亿美元的产业。这项研究的动机是这样一个事实，即更广泛的MEMS材料将提供更广泛的功能，并大大扩展MEMS应用的种类。高温MEMS器件特别适用于：航空、汽车、发电、海底钻井和化工加工等行业，在这些行业中，MEMS在恶劣环境中的传感和引导将提供更好的反馈和控制。金属MEMS合金具有高密度、导电性和导热性、强度、延展性和韧性；低成本；以及用于复杂几何形状的制造路线，对这些应用特别有吸引力。但是，能够以亚微米分辨率雕刻的高度工程化的金属合金目前还不在现有的MEMS材料中。为此，约翰霍普金斯大学(JHU)和通用电气全球研究中心(GEGR)组成了一个跨学科团队，负责开展一项合作计划，开发用作高温MEMS传感器和微开关的金属MEMS合金。在GEGR的长期实习将为学生提供关于系统级材料集成的宝贵视角。参加Sabes推广计划(JHU和巴尔的摩市公立学校之间由NSF赞助的合作伙伴关系)也为PI和他的学生提供了发扬光大的机会，让巴尔的摩的小学生对STEM活动有了独特的看法。技术摘要：来自约翰霍普金斯大学(JHU)和通用电气全球研究(GEGR)的一个跨学科团队正在开展一个合作项目，开发用于高温MEMS传感器和微开关的金属MEMS合金。此次合作的动机在于希望将MEMS材料集从硅扩展到可以在微观尺度上沉积和成形的金属合金，并提供诱人的性能平衡：导电性和热导性、高密度、低热膨胀、强度、延展性和韧性。需要解决的智力挑战包括制定一项以科学为基础的议定书，以开发具有必要的物理和机械性能并可在极端环境中使用的金属MEMS合金，例如300-500°C的温度，工作寿命超过一年。已经确定了候选的单相和多相合金，并正在利用这些合金在五个领域提高对科学的认识：(1)在微观尺度上加工和成形金属合金的技术；(2)尺寸稳定性的合金设计；(3)在远离平衡状态下沉积的合金中独特的微观组织-机械性能路径和关系；(4)微观结构演变的热和机械驱动因素；以及(5)金属MEMS合金的商业应用。JHU的基本工艺-结构-性能研究旨在为同时开发下一代MEMS开关和传感器提供基础。GEGR的长期实习计划，将为来访的研究生提供宝贵的系统级材料集成的视角。此外，参与Sabes项目(JHU和巴尔的摩市公立学校之间由NSF赞助的合作伙伴关系)为PI和他的学生提供了一个机会，让巴尔的摩的小学生对STEM研究有一个独特的视角。

Non-technical Summary: Over the past several decades micro-devices and microelectromechanical systems (MEMS) have found uses as ink jet printers, accelerometers, gyroscopes, pressure sensors, and digital light projectors and have become a multi-billion dollar industry. This study is motivated by the fact that a broader spectrum of MEMS materials would offer a wider range of functionality and fuel a greatly expanded assortment of MEMS applications. Elevated temperature MEMS devices are of particular interest in: aviation, automotive, power generation, sub-sea drilling, and chemical processing industries in which MEMS sensing and guidance in harsh environments would provide enhanced feedback and control. Metal MEMS alloys that offer: high density, electrical and thermal conductivity, strength, ductility and toughness; low cost; and fabrication routes for complex geometries would be especially attractive for these applications. But, highly engineered metallic alloys that can be sculpted with submicron resolution are currently not in the suite of available MEMS materials. For this reason, an interdisciplinary team from Johns Hopkins University (JHU) and General Electric Global Research (GEGR) has been formed to undertaking a collaborative program to develop Metal MEMS alloys for use as high temperature MEMS sensors and micro-switches. Extended internships at GEGR will provide students with an invaluable perspective on systems level materials integration. Participation in the SABES outreach program (an NSF-sponsored partnership between JHU and Baltimore City Public Schools) also provides the PI and his students with the chance to pay it forward by giving Baltimore elementary school students a unique perspective on STEM activities.Technical Summary:An interdisciplinary team from Johns Hopkins University (JHU) and General Electric Global Research (GEGR)is undertaking a collaborative program to develop metal MEMS alloys for high temperature MEMS sensors and micro-switches. The motivation for this collaboration lies in the desire to expand the MEMS material set beyond silicon to metallic alloys that can be deposited and shaped on the micro-scale and offer an attractive balance of properties: electrical and thermal conductivity, high density, low thermal expansion, strength, ductility, and toughness. The intellectual challenges to be addressed include the establishment of a science-based protocol for developing metal MEMS alloys that possess requisite physical and mechanical properties and can be used in extreme environments, e.g. temperatures of 300-500ºC for operational lifetimes exceeding one year. Candidate single- and multi-phase alloys have been identified and are being used to improve scientific understanding in five areas: (i) techniques for processing and shaping metallic alloys at the micro-scale, (ii) alloy design for dimensional stability, (iii) unique microstructure-mechanical property pathways and relations in alloys deposited far-from-equilibrium, (iv) thermal and mechanical drivers for microstructural evolution, and (v) integration of metal MEMS alloys into commercial applications. Fundamental processing-structure-properties studies at JHU have been designed to provide a foundation for concurrent GEGR efforts on the development of next-generation MEMS switches and sensors. Extended internships at GEGR are planned and will provide the visiting graduate student with an invaluable perspective on systems level materials integration. Moreover, participation in the SABES program (an established NSF-sponsored partnership between JHU and Baltimore City Public Schools) provides the PI and his students the chance to give Baltimore elementary school students a unique perspective on STEM research.