熔体快淬LaFe11.85Si1.15合金磁热性能的研究

Research on Magnetocaloric Properties of LaFe11.85Si1.15 Alloys Prepared by Melt-spinning Method

摘要:

本文通过电弧熔炼、熔体快淬及后续热处理,制备出了具有大磁熵变和磁滞损耗小的LaFe11.85Si1.15合金薄带。研究了不同热处理工艺对合金薄带物相组成、微观结构演变、磁熵变、居里温度及巡游电子变磁转变的影响。研究发现,不同退火时间对合金的1：13相含量和磁热效应影响显著,其中退火10 h所制薄带的1：13相含量最高,磁熵变最大,其在0-5 T磁场变化下,磁熵变和制冷能力分别可达20.54 J/(kg K)和417.21 J/kg,且具有明显的磁场诱导巡游电子变磁转变现象。而退火时间较短则不利于1：13相的形成,退火时间过长会引起1：13相的分解和a-Fe相含量的增加。

Abstract:

LaFe11.85Si1.15 ribbons with large magnetic entropy change and minor magnetic hysteresis were prepared by melt-spinning technique followed by heat treatment. The influences of different heat treatment processes on phase constitution, microstructure evolution, magnetic entropy change, Curie temperature and itinerant electron metamagnetic transitions were investigated in details. It was shown that the annealed processes had a great influence on the content of 1: 13 phase and magnetocaloric effect. For LaFe11.85Si1.15 alloy prepared under the annealed time of 10 h at 1050 ℃, the maximum △SM value of 20.54 J/(kg K) and the refrigerating capacity of 417.21 J/kg can be acquired due to the high content of 1:13 phase in the magnetic field of 0-5 T, and the phenomenon of itinerant electron metamagnetic transition can be observed, obviously. The shorter annealed time is not beneficial in the formation of 1:13 phase. Meanwhile, too long annealing time can also lead to the decomposition of 1: 13 phase and increased of a-Fe phase.