The paper assesses the applicability of advanced atomic resolution displacement measurement techniques to characterize dislocation character in metallic materials using simulated images derived from anisotropic elasticity and actual measurements in high entropy alloys. We draw attention to two techniques: the real space method of template matching (TeMA) and the reciprocal space method of geometric phase analysis (GPA) and provide a critical assessment. These techniques have limitations for direct evaluation of full dislocations Burgers vector or when local displacements are exceeding 50% lattice spacing. This is clearly illustrated with simulated arctangent displacement profiles reminiscent of dislocation cores. An approach for circumventing this limitation is suggested in the form of a nearest neighbor correction. Additionally, a methodology for determination of the Burgers vector is introduced on the basis of a vectorial rendering of the displacement field upon consideration of two zone axis measurements and applied to TeMA and GPA. The experimental results conform to the Burgers vector of a full lattice dislocation in the FCC crystal structure of the High-Entropy Alloy (HEA). The comparison of simulated and experimental images proves the efficacy of the HR-TEM (High Resolution Transmission Electron Microscopy) displacement mapping techniques while pointing to the need for caution in case of large displacements.

中文翻译：

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高熵合金中位错的高分辨率原子尺度表征：模板匹配和几何相分析的关键评估

本文使用源自各向异性弹性的模拟图像和高熵合金的实际测量，评估了先进的原子分辨率位移测量技术在表征金属材料中位错特征的适用性。我们提请注意两种技术：模板匹配的实空间方法 (TeMA) 和几何相位分析的倒易空间方法 (GPA)，并提供关键评估。这些技术在直接评估完全位错 Burgers 矢量或局部位移超过 50% 晶格间距时存在局限性。这可以通过模拟的反正切位移曲线清楚地说明，这让人想起位错核心。建议采用最近邻校正的形式来规避此限制。此外，在考虑两个区域轴测量的情况下，在位移场的矢量渲染的基础上引入了一种确定伯格斯矢量的方法，并将其应用于 TeMA 和 GPA。实验结果符合高熵合金 (HEA) FCC 晶体结构中全晶格位错的 Burgers 矢量。模拟和实验图像的比较证明了 HR-TEM（高分辨率透射电子显微镜）位移映射技术的有效性，同时指出在大位移的情况下需要谨慎。实验结果符合高熵合金 (HEA) FCC 晶体结构中全晶格位错的 Burgers 矢量。模拟和实验图像的比较证明了 HR-TEM（高分辨率透射电子显微镜）位移映射技术的有效性，同时指出在大位移的情况下需要谨慎。实验结果符合高熵合金 (HEA) FCC 晶体结构中全晶格位错的 Burgers 矢量。模拟和实验图像的比较证明了 HR-TEM（高分辨率透射电子显微镜）位移映射技术的有效性，同时指出在大位移的情况下需要谨慎。