NiMnSnCo磁制冷材料快速凝固过程及微观结构研究

项目名称： NiMnSnCo磁制冷材料快速凝固过程及微观结构研究

项目编号： No.51201096

项目类型： 青年科学基金项目

立项/批准年度： 2013

项目学科： 金属材料学科

项目作者： 郑红星

作者单位： 上海大学

项目金额： 25万元

中文摘要： 单辊快速凝固技术在NiMn基磁制冷材料制备中倍受青睐，但现有研究对凝固过程关注较少。本项目综合考虑磁性原子合金化效应，利用单辊快速凝固技术能够显著提高固溶度的特性，将高比例Co原子以整体掺杂的方式强制固溶进入NiMnSn基体中，探索通过凝固过程控制，制备超性能低成本NiMnSnCo磁制冷材料的可能性。在项目开展过程中，首先对凝固过程中NiMnSnCo材料的物相选择及竞争行为进行分析，确定出获取单相材料的成分范围及条件；其次在考察材料结构相变、磁性转变以及磁性能的基础上，将先进的原子探针层析技术引入结构分析中，逐个探测原子，重构材料三维空间中不同种类原子的排布，结合X射线衍射技术，从原子层面解析其微观结构特征。本项目的科学意义在于从原子层面揭示材料结构与性能之间的内在关系，探索凝固过程控制技术，为新型NiMn基磁制冷材料的研发提供技术支持和理论依据。

中文关键词： 快速凝固；Heusler型NiMn基材料；马氏体相变；磁制冷效应；晶体生长

英文摘要： Melt spinning technique has attracted more attention for the fabrication of NiMn-based magnetocaloric materials, however, little information on the solidification process can be found. Therefore, in this proposal we suggest to develop super-performance low-cost NiMnSnCo materials. Supersaturated cobalt atoms will be doped into NiMnSn matrix, i.e., the studied subjects will be (NiMnSn)(100-x)Cox materials, different from conventional atomic substitution mode. The phase selection and competition behavior will first be analyzed and based on this, the composition range and fabrication conditions will be obtained for the metastable single-phase materials, and then the martensitic transformation, magnetic transition behavior and magnetic properties will be investigated. Advanced atom probe tomography will be introduced to detect atoms one by one, the atomic site occupation will be accurately reconstructed, together with x-ray diffraction technique, the information on the atomic structure will be clarified. The scientific significance is to reveal the internal link between atomic structure and magnetic properties, and to explore how to control the solidification process, and we expect that the research could provide technical supports and theoretical evidence for the future development of NiMn-based magnetocaloric mate

英文关键词： Rapid Solidification；Heusler NiMn based Materials；Martensitic Tansformation；Magnetocaloric Effect；Crystal Growth