Abstract Segregation of solute atoms at twin boundaries (TBs) plays a critical role in mechanical properties and thermal stability of magnesium alloys. Here, segregation structures at {10 1 ¯ 1}, {10 1 ¯ 2} and {10 1 ¯ 3} TBs are characterized in a Mg-Ag alloy by means of the atomic resolution high-angle annular dark-field technique based on scanning transmission electron microscopy. Of particular finding is the unique complex segregation at {10 1 ¯ 3} TBs, where Ag atoms occupy both substitutional and interstitial sites. By contrast, Ag atoms only substitutionally segregate at {10 1 ¯ 1} and {10 1 ¯ 2} TBs. Calculation simulation of segregation energy and three-dimensional structure of TBs helps understanding of hybrid segregation.

中文翻译：

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Mg-Ag 合金中孪晶边界处的原子偏析

摘要 溶质原子在孪晶界（TBs）的偏析对镁合金的力学性能和热稳定性起着至关重要的作用。在这里，通过基于原子分辨率的高角度环形暗场技术，在 {10 1 ¯ 1}、{10 1 ¯ 2} 和​​ {10 1 ¯ 3} TBs 处的偏析结构在 Mg-Ag 合金中被表征扫描透射电子显微镜。特别的发现是 {10 1 ¯ 3} TBs 处独特的复杂偏析，其中 Ag 原子同时占据置换位点和间隙位点。相比之下，Ag 原子仅在 {10 1 ¯ 1} 和 {10 1 ¯ 2} TBs 处发生置换分离。TBs的偏析能和三维结构的计算模拟有助于理解混合偏析。