稀土超磁致伸缩材料的磁场热处理研究

Magnetic Annealing of Giant Magnetostrictive Materials

超磁致伸缩材料是一种先进的能量转换材料,在高新技术和国防军工领域具有重要的应用价值。在概述TbDyFe超磁致伸缩材料的特点及发展现状基础上,重点介绍了<110>取向材料的磁场热处理研究。在实验方面,采用区熔定向凝固技术制备了<110>取向TbDyFe多晶材料,在略高于居里点温度退火时施加磁场,不改变晶体学择优取向和凝固组织,但能调控初始磁畴分布状态,改变服役时的磁矩运动过程,从而改善材料磁致伸缩和力学性能。在模拟研究方面,建立了基于能量最低原理的磁畴旋转模型,模拟了磁热感生各向异性诱导的初始磁矩再取向过程,得到了形成单轴各向异性的临界值;模拟了感生各向异性强弱对磁致伸缩"Jump"效应的影响规律,探讨了磁场热处理对<110>取向晶体磁致伸缩的作用机理。

Giant magnetostrictive material （GMM） is a kind of advanced energy transfer material, which is of importance for applications in high-technical devices. We firstly present in this work the characteristics and developments of TbDyFe GMMs. A review is then given on our recent activities in magnetically annealed TbDyFe GMMs with 〈 110 〉 crystal orientation. Both experimental and theoretical studies demonstrate that magnetic annealing is capable of tuning the initial magnetic moment orientation and hence improving the magnetomechanical performance through changing the moment movement processes. Evidences including magnetic force microscopy （MFM） images, magnetostriction, magnetic induction, stress-strain curves and domain rotation simulation are provided.