CAREER: Computational Approaches for Multi-scale Design of Magnetostrictive Alloys

该学院早期职业发展(CALEAR)项目的研究目标是对制造低成本多晶铁-镓合金(Galfenol)的热机械工艺进行理论和计算研究，其性能可与昂贵的单晶相媲美。在热机械加工过程中，Galfenol的性质发生了显著的变化。温轧和退火的样品保持了高的磁致伸缩，但变得脆性；而冷轧的样品具有高的屈服强度，但失去了磁致伸缩。研究的重点将是通过模拟加工过程中的组织演变来预测和控制这些变化。经过验证的模型将通过多尺度晶体塑性模拟来捕捉晶体织构演化、晶粒形核、晶粒长大和磁化取向的演化。开发了一种有限应变均匀化技术来研究磁场和应力场耦合作用下的最终微结构响应。然后，将使用多尺度灵敏度分析算法来识别导致最佳性能的热机械过程。这项工作将导致在磁机械设备中开发廉价的传感器和执行器，包括负载传感器、能量采集设备、跟踪和定位系统。将为工程力学本科生开发一个教育工具，允许以图形方式选择微结构特征，使磁致伸缩执行器在各种变形模式下的性能最大化。研究部分将通过研究生培训、通过SURE(暑期本科生工程学研究)、SROP(少数族裔本科生暑期研究机会)计划为本科生提供实践研究机会，以及通过密歇根大学工程外联和参与办公室为K-12教育提供外展计划，纳入更大的教育努力。

The research objective of this Faculty Early Career Development (CAREER) project is the theoretical and computational investigation of thermomechanical processes for manufacturing low-cost polycrystalline iron-gallium alloy (Galfenol) with properties comparable to expensive single crystals. Significant changes in properties occur during thermo-mechanical processing of Galfenol. Warm-rolled and annealed specimens retain high magnetostriction but become brittle; whereas, cold rolled specimens have high yield strength but lose their magnetostriction. The research will focus on predicting and controlling these changes by modeling microstructure evolution during processing. The validated model will capture crystallographic texture evolution, grain nucleation, grain growth and evolution of magnetization orientation using multi-scale crystal plasticity simulations. A finite strain homogenization technique will be developed to investigate final microstructural response under coupled magnetic and stress fields. Thermo-mechanical processes that lead to optimal properties will then be identified using a multi-scale sensitivity analysis algorithm. This work will lead to the development of inexpensive sensors and actuators in magnetomechanical devices including load sensors, energy harvesting devices, tracking and positioning systems. An educational tool for undergraduate engineering mechanics students will be developed that will allow graphical selection of microstructural features that maximize magnetostrictive actuator performance under various deformation modes. The research component will be integrated into a larger educational effort through graduate student training, hands-on research opportunity for undergraduate students through the SURE (Summer Undergraduate Research in Engineering), SROP (Summer research opportunity for minority undergraduate students) program and outreach programs for K-12 education through the Office of Engineering Outreach and Engagement at the University of Michigan.