Two-dimensional interface superstructures assembled by well-ordered solute atoms

PJ Yang and SS Li and HB Xie and JF Jin and CW Liu and HC Pan and YP Ren and WT Jia and YP Zong and GW Qin, JOURNAL OF MATERIALS SCIENCE & TECHNOLOGY, 142, 253-259 (2023).

DOI: 10.1016/j.jmst.2022.10.034

Segregation of solutes/impurities in the interfaces plays a decisive role in material performances. However, the segregation of solutes/impurities remains elusive due to the diversity of interfacial structures. Here, in a Mg-Nd-Mn ternary model system, two ordered novel two-dimensional (2D) interfacial superstructures formed by periodic segregation of solute atoms in special symmetric and asymmetric tilt grain boundaries (GBs) have been systematically investigated. Z-Contrast high-angle annular dark-field scanning transmission electron microscopy (HAADF-STEM) observations provided the atomic-level details on how solute atoms were arranged on these special partially coherent tilt GBs. The strained conditions of each atomic site at the tilt GBs were accurately reproduced by molecular dynamics (MD) simulations plus Voronoi analysis, and the rationality of solute segregation in each atomic-site was evaluated carefully based on the first-principles calculations. These findings expand our knowledge of solute/impurity segregation behaviors in the interfaces, especially the co-segregation behaviors in multi-component materials. (c) 2022 Published by Elsevier Ltd on behalf of The editorial office of Journal of Materials Science & Technology.

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