Gd-La-Al合金的微观结构与磁热效应  

Microstructure and Magnetocaloric Effect of Gd-La-Al Alloy

作　　者：高磊 戴默涵 程娟[1] 刘翠兰[1] 王鹏宇 李兆杰[1] Gao Lei;Dai Mohan;Cheng Juan;Liu Cuilan;Wang Pengyu;Li Zhaojie(State Key Laboratory of Baiyunobo Rare Earth Resource Researches and Comprehensive Utilization,Baotou Research Institute of Rare Earths,Baotou 014030,China)

机构地区：[1]包头稀土研究院白云鄂博稀土资源研究与综合利用国家重点实验室,内蒙古包头014030

出　　处：《中国稀土学报》2024年第1期62-69,I0003,共9页Journal of the Chinese Society of Rare Earths

基　　金：“十四五”国家重点研发计划重点专项(2021)——稀土新材料(2021YFB3501200);内蒙古自然科学基金项目(2021MS05016)资助。

摘　　要：以Gd_(3-x)La_(x)Al_(2)(x=0,0.1,0.2,0.3)磁制冷材料为研究对象,系统分析了合金的相组成、微观组织及磁热性能。结果表明,Gd_(3-x)La_(x)Al_(2)(x=0,0.1,0.2,0.3)合金均由Gd_(3)Al_(2)相、GdAl相、Gd_(2)Al相组成。La原子主要分布于Gd_(2)Al相,且La元素的添加具有调控Gd Al相形貌的作用。对M-T曲线求一阶导数可得,Gd_(3-x)La_(x)Al_(2)(x=0,0.1,0.2,0.3)合金的居里温度T_(C)随La含量的增加呈逐渐降低的趋势,分别为275,267,261,252 K,适用于近室温领域的制冷。利用Landau理论,分析了Gd_(3-x)La_(x)Al_(2)(x=0,0.1,0.2,0.3)合金的磁相变特征。分析拟合结果可知,Gd_(3-x)La_(x)Al_(2)(x=0,0.1,0.2,0.3)合金在居里温度T_(C)附近发生二级磁相变。0~2 T磁场下Gd_(3)Al_(2)合金的最大等温磁熵变(ΔS_(M))^(max)为3.05 J·kg^(-1)·K^(-1),最大绝热温变(ΔT_(ad))^(max)为2.12 K,表现出良好的磁热性能。Taking Gd_(3-x)La_xAl_(2)(x=0,0.1,0.2,0.3) magnetic refrigeration materials as the research object,the phase composition,microstructure and magnetocaloric properties were systematically analyzed.The results show that all Gd_(3-x)La_xAl_(2)(x=0,0.1,0.2,0.3) alloys are composed of Gd3Al2 phase,GdAl phase and Gd_(2Al) phase.La atoms are mainly distributed in Gd2Al phase and the addition of La can regulate the morphology of GdAl phase.The Curie temperature TC of Gd_(3-x)La_xAl_(2)(x=0,0.1,0.2,0.3) alloys decreases gradually with the increase of La content,which is 275,267,261 and 252 K,respectively.The magnetic transition characteristics of Gd_(3-x)La_xAl_(2)(x=0,0.1,0.2,0.3) alloys were analyzed by Landau theory.The fitting results show that Gd_(3-x)La_xAl_(2)(x=0,0.1,0.2,0.3) alloys have the advantage of low hysteresis due to second-order magnetic phase transition near Curie temperature T_C.The maximum isothermal magnetic entropy change (ΔS_M)^(max) of Gd_3Al_(2) alloy is 3.05J·kg^(-1)·K^(-1),and the maximum adiabatic temperature change (ΔTad)^(max) is 2.12 K,showing excellent magnetocaloric properties.

关 键 词：磁制冷材料 微观组织 磁相变 磁热性能 稀土 

分 类 号：TB64[一般工业技术—制冷工程]