MPB准同型相界对Laves相稀土合金磁弹效应的影响机理研究

磁致伸缩材料是用于换能器和传感器的重要磁性功能材料。利用准同型相界(MPB)原理设计Laves相结构的铁磁稀土合金，是近年来研究和设计磁致伸缩材料的新途径。本项目拟在前期研究成果基础上，以不同MPB相界的相变路径对磁弹效应的影响为出发点，结合晶体结构对称性测试和微观结构观测，分析磁弹效应-相变路径-微观结构的关联，并基于相场模拟的方法建立朗道自由能理论模型，最终揭示MPB对Laves相铁磁稀土合金磁弹效应的影响机理，并阐述不同铁磁MPB体系中磁弹效应增强或减弱的原因。本项目的研究对于设计高性能MPB型Laves相磁致伸缩材料具有重要的理论意义和应用价值。

Magnetostrictive materials are important magnetic functional materials that can be used as the key components in transducers and sensors. Recently, designing Laves-structure rare-earth alloys with the principle of morphotropic phase boundary (MPB) is a new route to study magnetostrictive materials. Based on our previous work, we propose to study the influence of MPB on magnetoelasticity of Laves-structure rare-earth alloys. First, the phase transition sequence of MPB compositions will be identified. Then, the observation of microscopic structure at MPB will be performed and we will analyze the relationship between magnetoelasticity, phase transition sequence, and microscopic structure. Finally, the Landau-theory-based model with phase field modelling method will be proposed to reveal how MPB influences the magnetoelasticity of Laves-structure rare-earth alloys, and answer the question that why magnetoelasticity can be enhanced in some MPB systems and weakened in others. Our work will shed light on designing high-performance Laves-structure magnetostrictive materials.