Selective impurity segregation at a near-Σ5 grain boundary in MgO
Selective impurity segregation at a near-Σ5 grain boundary in MgO
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DOI：
10.1007/s10853-014-8016-7
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发表时间：
2014-01
影响因子：
4.5
通讯作者：
M. Saito;Zhongchang Wang;Y. Ikuhara
中科院分区：
文献类型：
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作者：
M. Saito;Zhongchang Wang;Y. Ikuhara
晶界 (GB) 及其相关的杂质偏析通常会影响或改变许多多晶材料的性能。然而，它们的原子尺度结构仍然难以在空间上解析，特别是对于那些方向未对准的结构。在这里，我们应用双晶技术来制造近 Σ5 GB 的 MgO，其与精确的 Σ5 取向关系存在一定的错位角，并在该晶界上表现出意想不到的选择性杂质偏析行为。我们发现近Σ5GB由五个精确Σ5GB结构单元和一个变形Σ17GB单元的交替阵列组成，有趣的是Ca和Ti杂质与Σ5GB结构单元共偏析，但不与变形Σ17GB结构单元共偏析。这些发现对于理解具有错位和杂质偏析的晶界以及将结构与多晶材料的性能相关联非常重要。
Grain boundaries (GBs) together with their associated impurity segregation often affect or alter properties of many polycrystalline materials. However, their atomic-scale structures remain difficult to resolve spatially, especially for those with an orientation misalignment. Here, we apply a bicrystal technique to fabricate the near-Σ5 GBs of MgO with a misalignment angle from the exact Σ5 orientation relationship and show an unexpected selective impurity segregation behavior at this GB. We find that the near-Σ5 GB comprises an alternating array of five exact Σ5 GB structural units and one deformed Σ17 GB unit, and interestingly that the Ca and Ti impurities are co-segregated to the Σ5 GB structural units, yet are not to the deformed Σ17 GB structural units. The findings are important for the understanding of GBs with a misalignment and impurity segregation and for correlating structures with properties in polycrystalline materials.