Acceleration of B2/L21 Order-disorder Transformation in Ni2MnAl Heusler Alloys by In-magnetic-field Annealing
Acceleration of B2/L21 Order-disorder Transformation in Ni2MnAl Heusler Alloys by In-magnetic-field Annealing
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DOI：
10.1016/j.jmmm.2021.168908
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发表时间：
2021-12
影响因子：
2.7
通讯作者：
R. Kobayashi;Y. Mitsui;R. Umetsu;Kohki Takahashi;K. Koyama
中科院分区：
文献类型：
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作者：
R. Kobayashi;Y. Mitsui;R. Umetsu;Kohki Takahashi;K. Koyama
Ni_2MnAl合金的L21/B2有序-无序转变温度低，难以合成有序度高的铁磁L21相。结果表明，磁场促进了B2相向L21相的转变。在673 K的磁场中退火，磁化强度增加，这表明有序化到L21相的加速。从磁场诱导转变温度的变化、退火温度下有序度的提高和L21核临界半径的减小等方面讨论了磁场对B2/L21有序-无序转变的影响。用Johnson-Mehl-Avrami方程计算了L21相的生长动力学，结果表明15 T退火使L21相的生长速度比零场退火快5.7倍。研究结果表明，磁场有助于缩短铁磁L21-Ni 2 MnAl合金的退火时间。
FerromagneticL21phase of Ni2MnAl with high order degree is difficult to synthesize because of lowL21/B2 order-disorder transformation temperature. It is found that magnetic field accelerated the transformation from the antiferromagnetic disorderedB2 to orderedL21phase. Magnetization increased by in-magnetic-field annealing at 673 K, which indicated the acceleration of the ordering toL21phase. Magnetic field effects on theB2/L21order-disorder transformation were discussed based on magnetic-field-induced change of transformation temperature, enhancement of degree of order at annealing temperature, and reduction of critical radius ofL21nuclei. Growth kinetics ofL21phase were evaluated by Johnson-Mehl-Avrami equation, which indicated that 15-T annealing accelerated the growth ofL21phase 5.7 times faster than zero-field annealing. Our results showed that magnetic field can contribute to shortening the annealing time for synthesis of ferromagneticL21-Ni2MnAl alloy.