Abstract Interfacial solute segregation behavior of P in nanocrystalline (NC) Ni alloys is investigated at the atomic scale using cross-correlative PED-APT measurements and atomistic simulations. Inhomogeneous P-segregation in grain boundaries (GBs) of NC Ni is observed from both experimental measurements and simulation calculations. Interfacial excess (IE) of the solute within GBs is further studied as function of GB misorientation. Significant scatter is detected in the IE of boundaries with similar misorientation angles and even within special boundaries with identical Σ values. From atomistic simulations, a general trend of increasing IE with initial GB energy and volume is observed but with poor correlation, indicating that the segregation behavior cannot be captured with a single average measure of the entire GB character. Rather the results suggest that the extent of interfacial solute segregation correlates better with fraction of high energy atomic sites in the boundary. By comparing IE values with thermodynamic model predictions, it is shown that the interfacial segregation behavior is strongly influenced by the energy distribution of atomic sites in the GBs. However, in order to predict the extent of solute segregation, the evolution of the atomic energy landscape in the GB with continuous solute segregation must be considered.

中文翻译：

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晶界特征及其演变对纳米晶 Ni-P 界面溶质偏析行为的影响

摘要 使用互相关 PED-APT 测量和原子模拟在原子尺度上研究了 P 在纳米晶 (NC) Ni 合金中的界面溶质偏析行为。从实验测量和模拟计算中都观察到 NC Ni 晶界 (GB) 中的不均匀 P 偏析。GB 内溶质的界面过量 (IE) 被进一步研究为 GB 错误定向的函数。在具有相似取向角的边界的 IE 中甚至在具有相同 Σ 值的特殊边界内检测到显着的散射。从原子模拟中，观察到 IE 随着初始 GB 能量和体积增加的总体趋势，但相关性较差，这表明分离行为无法通过整个 GB 特征的单一平均测量来捕获。相反，结果表明界面溶质偏析的程度与边界中高能原子位点的比例更好地相关。通过将 IE 值与热力学模型预测进行比较，表明界面偏析行为受 GB 中原子位点能量分布的强烈影响。然而，为了预测溶质偏析的程度，必须考虑具有连续溶质偏析的 GB 中原子能景观的演变。