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

该学院早期职业发展（CAREER）项目的研究目标是对制造低成本多晶铁镓合金（Galfenol）的热机械过程进行理论和计算研究，该合金具有与昂贵的单晶相当的性能。Galfenol的热机械加工过程中，性能发生显著变化。温轧和退火试样保持高的磁致伸缩，但变得脆，而冷轧试样具有高的屈服强度，但失去其磁致伸缩。该研究将侧重于通过模拟加工过程中的微观结构演变来预测和控制这些变化。验证模型将捕获晶体织构演化，晶粒成核，晶粒生长和磁化方向的演变，使用多尺度晶体塑性模拟。有限应变均匀化技术将被开发，以调查耦合磁场和应力场下的最终微观结构响应。然后，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。这项工作将导致廉价的传感器和执行器的磁机械设备，包括负载传感器，能量收集设备，跟踪和定位系统的发展。本科工程力学学生的教育工具将开发，将允许图形选择的微观结构的功能，最大限度地提高磁致伸缩致动器的性能在各种变形模式下。研究部分将通过研究生培训，通过SURE（夏季本科生工程研究），SROP（少数民族本科生夏季研究机会）计划和K-12教育的推广计划为本科生提供实践研究机会，并通过密歇根大学工程推广和参与办公室进行更大的教育工作。

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.