Phase transitions as a tool for tailoring magnetostriction in intrinsic Fe-Ga composites
Phase transitions as a tool for tailoring magnetostriction in intrinsic Fe-Ga composites
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DOI：
10.1016/j.actamat.2017.03.049
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发表时间：
2017-05
期刊：
影响因子：
9.4
通讯作者：
V. Palacheva;A. Emdadi;Friederike Emeis;I. Bobrikov;A. Balagurov;S. Divinski;G. Wilde;I. Golovin-I.-Golo
中科院分区：
文献类型：
--
作者：
V. Palacheva;A. Emdadi;Friederike Emeis;I. Bobrikov;A. Balagurov;S. Divinski;G. Wilde;I. Golovin-I.-Golo
Fe-Ga合金表现出独特的功能特性，如磁致伸缩，可以从铁基合金中最高的正值变化到负值，包括零磁致伸缩，如果选择适当的成分和热处理。这种显著的行为与该合金族中相当复杂的相变序列有关，这些相变序列仍然没有得到解决。在早期的研究中，Fe-Ga合金中的相变是通过X射线衍射研究的，其提供的结构信息仅限于近表面样品区域。本文用电子背散射衍射和原位中子衍射分别对Fe-27 Ga型块体合金中源于fcc相和bcc相的D 03相和L12相进行了表征。这些阶段之间的不同比例，其特征在于不同符号的磁致伸缩值，实现使用等温退火处理，产生本征复合材料的合金。取决于D 03和L12相的相对分数，合金的磁致伸缩值λS在+100至−50 ppm之间变化，包括在400 °C下退火600分钟后L12：D 03 = 2：1的合金的λS= 0的值，从而证明了这些先进合金中磁致伸缩的可控调节。
Fe-Ga alloys exhibit unique functional properties such as magnetostriction that can be varied from the highest positive values among iron-based alloys to negative values including zero magnetostriction, if proper compositions and heat treatments are chosen. This remarkable behavior is related to rather complex phase transformation sequences in this alloy family that are still unresolved. In earlier studies, the phase transformations in Fe-Ga alloys were studied by X-ray diffraction, which provides structural information limited to the near-surface sample area. In this paper, we use electron back-scatter diffraction andin situneutron diffraction to characterize the D03and L12phases that originate from the fcc and bcc phases in the Fe-27Ga type bulk alloy, respectively. Different ratios between these phases, characterized by magnetostriction values of different signs, were achieved using an isothermal annealing treatment that produces an intrinsic composite in the alloy. Depending on the relative fraction of the D03and L12phases, the magnetostriction values of the alloy, λS, vary from +100 to −50 ppm, including the value of λS= 0 for the alloy with L12:D03= 2:1 achieved after 600 min annealing at 400 °C, thus demonstrating the controlled adjustment of magnetostriction in these advanced alloys.