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Reduced Annealing Time and Enhanced Magnetocaloric Effect of La(Fe, Al) 13 Alloy by La-nonstoichiometry and Si-doping
Acta Metallurgica Sinica-English Letters ( IF 3.5 ) Pub Date : 2020-07-25 , DOI: 10.1007/s40195-020-01107-y
Liang Yang , Jun Li , Defang Tu , Joel C. J. Strickland , Qiaodan Hu , Hongbiao Dong , Jianguo Li

LaFe13−xMx (M = Si, Al) alloys are promising for use in magnetic refrigeration. However, they require long annealing time (30 days) in order to optimize the magnetocaloric properties. Research has shown that the addition of extra La in off-stoichiometric alloys can greatly shorten the annealing time. Therefore, the purpose of this study is to investigate the influence of the extra addition of La on the annealing properties of a new off-stoichiometric La1.7Fe11.6Al1.4−xSix (x = 0, 0.1, 0.4) alloys. It was demonstrated that after a 36h annealing time, a large volume fraction of 1:13 magnetocaloric phase was obtained for all alloys. Further microstructural analysis of the off-stoichiometric La1.7Fe11.6Al1.4−xSix alloys revealed a facet-like grain morphology. The La1.7Fe11.6Al1.4 and La1.7Fe11.6Al1Si0.4 alloys were shown to contain large 1:13 phase precipitates separated in a La-rich matrix, while the La1.7Fe11.6Al1.3Si0.1 alloy had a continuous 1:13 phase matrix with a fine dispersion of La-rich precipitates throughout. When the magnetic field varied between 0 and 2 T, the corresponding magnetic entropy change and relative cooling capacity for the La1.7Fe11.6Al1.3Si0.1 specimen were determined as 4.58 J/kg K and 173.6 J/kg, respectively. More importantly, the La1.7Fe11.6Al1.3Si0.1 alloy displayed only a slight volume change when the meta-magnetic phase transition occurred, which is promising for cyclic use.



中文翻译:

非化学计量比和硅掺杂缩短了La(Fe,Al)13合金的退火时间并增强了磁热效应

LaFe 13− x M xM  = Si,Al)合金有望用于磁制冷。但是,它们需要较长的退火时间(30天)以优化磁热性能。研究表明,在非化学计量合金中添加额外的La可以大大缩短退火时间。因此,本研究的目的是研究额外添加La对一种新的化学计量失当的La 1.7 Fe 11.6 Al 1.4− x Si xx = 0、0.1、0.4)合金。结果表明,经过36h的退火时间后,所有合金均获得了体积分数为1:13的磁热相。化学计量比为La 1.7 Fe 11.6 Al 1.4- x Si x的合金的进一步显微组织分析显示出小面状晶粒形态。结果表明,La 1.7 Fe 11.6 Al 1.4和La 1.7 Fe 11.6 Al 1 Si 0.4合金在富La的基体中分离出较大的1:13相沉淀,而La 1.7 Fe 11.6 Al 1.3 Si 0.1该合金具有连续的1:13相基质,并且富La沉淀物始终精细分散。当磁场在0和2 T之间变化时,La 1.7 Fe 11.6 Al 1.3 Si 0.1试样的相应磁熵变和相对冷却能力分别确定为4.58 J / kg K和173.6 J / kg。更重要的是,当发生亚磁性相变时,La 1.7 Fe 11.6 Al 1.3 Si 0.1合金仅显示出微小的体积变化,这有望用于循环使用。

更新日期:2020-07-25
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