近室温磁相变钆基非晶合金的开发及其磁热效应研究

Compared to crystalline magnetocaloric materials, rare earth based metallic glasses possess the advantages of much wider temperature range of large magnetocaloric effect (MCE), unique mechanical properties and excellent corrosion resistance, which make the alloy a promising candidate as magnetic refrigerants. However, the low magnetic transition temperature limits its application as a room temperature magnetic refrigeration material. In this proposal, the mechanism of the effects of ferromagnetic and non-magnetic elements on the electronic structure of Gd-based metallic glasses will be investigated, by which we want to reveal how the components and electronic structure affect on the glass forming ability (GFA), magnetic transition temperature and MCE. By optimizing the composition and preparation process, Gd-based metallic glasses with large GFA and excellent MCE near room temperature will be explored. Finally, Gd-based amorphous micro wires will be prepared using melt-extracted method and then the influence of size effect on the magnetocaloric properties near room temperature will be studied. The results are expected to provide experimental and theoretic guides for practical applications of rare earth based metallic glasses as magnetocaloric materials.

稀土基非晶合金相比于晶态磁制冷材料具有制冷温区宽、力学性能和耐腐蚀性能优异等优点，作为磁制冷工质具有广阔的应用前景。但是现有大磁熵变稀土基非晶合金的磁转变温度较低，限制了其作为室温磁制冷材料的应用。基于此，本项目拟通过研究铁磁性元素和非磁性元素对Gd基非晶合金电子结构的影响机制，从机理上阐明Gd基非晶合金的非晶形成能力、磁转变温度、磁热效应随合金成分和电子结构的变化规律；通过优化成分设计和制备工艺，获得兼具大非晶形成能力、优异力学性能和近室温优异磁热效应的Gd基非晶态制冷材料；利用熔体抽拉法制备Gd基非晶微丝，研究尺寸效应对其近室温磁热效应的影响规律。近室温具有大磁热效应的Gd基非晶态制冷材料的开发及相关机理研究，将为非晶合金作为磁制冷材料的实际应用提供实验基础和理论指导。

稀土基非晶合金相比于晶态磁制冷材料具有制冷温区宽、力学性能和耐腐蚀性能优异等优点，作为磁制冷工质具有广阔的应用前景。但是现有具有大磁熵变的稀土基非晶合金的磁转变温度较低，限制了其作为室温磁制冷材料的应用。针对以上问题，本项目开发了近室温具有大磁制冷能力的Gd基非晶纳米晶复合磁制冷材料；并研究了元素添加和外加磁场对Gd基非晶纳米晶的结构和磁相变温度的影响规律；最后，利用熔体抽拉技术开发了具有大磁热效应的高熵非晶合金微丝。相关研究成果将为非晶合金作为磁制冷材料的实际应用提供实验基础和理论指导。