CAREER: Engineering Meta-magnetic Shape Memory Alloys as the Future Generation of High Performance Magnetic Actuators

该学院早期职业发展奖的研究目标是研究亚磁性形状记忆合金(SMA)的基本性质，建立成分、微观结构和性能之间的关系，并通过热机械处理来设计微结构，以产生高应力输出的磁致动器。亚磁性SMA是一类新型的智能材料，其驱动机制是基于场致相变，其驱动应变比磁致伸缩材料大一个数量级，比著名的NiMnGa磁SMA高一个数量级，与传统SMA相当。通过系统地研究成分、晶体取向、磁热机械处理和应力状态对形状记忆和相变相的超弹性、形状记忆效应、相变温度、磁滞回线、居里温度和饱和磁化强度等磁性能的影响，可以对亚磁形状记忆合金的行为有更深入的了解。如果成功，这项研究将使新一代不同规模的磁致动器的制造成为可能，这将为现有的固态致动器技术提供一种替代方案，反过来将有利于我们社会的经济发展。这些致动器预计将导致高致动应力(30兆帕/特斯拉)、高致动应变(2-4%)，并在低磁场(2特斯拉)下以中频(10 KHz)工作。一个综合的研究和教育计划将建立在坚实的基础上，通过连接力学和材料科学社区，特别是通过使用智能材料，让本科生在他们的学术生涯早期接触到多学科的研究。通过与肯塔基大学成熟的当地推广项目合作，让一线中学教师参与智能材料项目，从而教育、增强他们的能力和激动人心的能力，将吸引大量代表性不足和经济困难的学生追求未来的工程职业生涯。

The research objective of this Faculty Early Career Development (CAREER) award is to study the fundamental properties of meta-magnetic shape memory alloys (SMAs) to establish composition, microstructure and property relationship and to engineer the microstructure through thermo-mechanical treatments to result in magnetic actuators with high stress output. Meta-magnetic SMAs are a new class of smart materials where their actuation mechanism is based on field-induced phase transformation which results in one order of magnitude greater actuation strain than magnetostrictive materials and one order of magnitude higher actuation stress than well known NiMnGa magnetic SMAs, comparable to those of conventional SMAs. A deeper understanding of meta-magnetic SMA behavior will be gained by a systematic study of the effects of composition, crystal orientation, magneto-thermo-mechanical treatments and stress state on shape memory and magnetic properties including superelasticity, shape memory effect, transformation temperatures, hysteresis, Curie temperature, and saturation magnetization of transforming phases. If successful, this research will enable the fabrication of a new generation of magnetic actuators at various scales that will provide an alternative to the existing solid-state actuator technology which in turn will benefit the economic development of our society. These actuators are expected to result in high actuation stress (30 MPa/Tesla), high actuation strain (2-4%), and to operate at medium frequencies (10 kHz) under low magnetic fields ( 2 Tesla). An integrated research and educational program will be built on strong foundations by bridging mechanics and materials science communities, through the use of smart materials in particular, to expose undergraduate students to multidisciplinary research early in their academic careers. Educating, empowering and exciting "front-line" middle and high school teachers by involving them in projects on smart materials through collaborations with well-established local outreach programs available at University of Kentucky will attract a large number of under-represented and economically-challenged students to pursue their future careers in engineering.