Yan, Keyu ; Xu, Yichen ; Niu, Jiejue ; Wu, Yuye ; Li, Yue ; Gault, Baptiste ; Zhao, Shiteng ; Wang, Xiaoxiao ; Li, Yunquan ; Wang, Jingmin ; Skokov, Konstantin P. ; Gutfleisch, Oliver ; Wu, Haichen ; Jiang, Daqiang ; He, Yangkun ; Jiang, Chengbao (2024)
Unraveling the origin of local chemical ordering in Fe-based solid-solutions.
In: Acta Materialia, 264
doi: 10.1016/j.actamat.2023.119583
Artikel, Bibliographie

Kurzbeschreibung (Abstract)

Local chemical ordering (LCO) can exert pronounced effects on both structural and functional properties, tailoring LCO domains at (sub-)nanoscale could offer an alternative material-design concept for yet unexplored performance. However, the origin of LCO remains an open question, making accurate manipulation of LCO extremely challenging. Here we selected the Fe-Ga magnetostrictive materials and demonstrated that LCO tetragonal structures play a significant role in optimizing the magnetostrictive properties. The “full-lifecycle”, including formation, evolution and dissolution of LCO, is concretely studied from the atomic-scale up by combined experimental and theoretical studies. The dynamic precipitation and dissolution processes of LCO L60 domains during isothermal aging are directly observed based on in-situ high-resolution transmission electron microscopy images, and the corresponding mechanisms are revealed by first-principles calculation. Based on the results, we evidence that LCO domain is a frozen-intermediate-state of a kinetically-slow solid-state phase transformation leading to the formation of the long-range-ordered equilibrium phase with a face-center-cubic structure. We confirm the reversibility of LCO during cycling treatments. Our findings shed light on the origin of LCO in a range of material systems, and we discuss directions for developing materials with superior performance by manipulating LCO domains.

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