In this study, we demonstrate the methodology systematically developed for dislocation loop (perfect and faulted loops) imaging and analysis in irradiated face-centered-cubic (FCC) alloys using scanning transmission electron microscopy (STEM). On-zone [001] STEM imaging was identified as the preferred choice based on the comparison to (i) on-zone STEM imaging using other major low-index zone axes, (ii) two-beam bright field imaging condition near the [001] zone axis using conventional TEM (CTEM), and (iii) Rel-Rod CTEM dark-field (DF) imaging near the [011] zone axis. The effect of STEM collection angle on the contrast formation of dislocation loops was also investigated. The developed method was confirmed by imaging all populations of perfect and faulted loops of types a/2〈110〉{110} and a/3〈111〉{111} found in an ion irradiated Ni₄₀Fe₄₀Cr₂₀ alloy. The proposed STEM-based technique can easily identify said loops with a size greater than 10 nm without any assumptions such as those commonly made using the conventional Rel-Rod CTEM-DF technique. The recommended methodology in this study is developed as a quick and convenient tool that can be generally applied to irradiated FCC-based materials due to their common crystallography.

在这项研究中，我们证明了系统开发的用于扫描面心立方（FCC）合金中位错环（完美和故障环）成像和分析的方法，方法是使用扫描透射电子显微镜（STEM）。基于与（i）使用其他主要低折射率区域轴的区域STEM成像，（ii）[001附近的两光束明场成像条件]的比较，将区域[001] STEM成像确定为优选选择使用常规TEM（CTEM）扫描区域轴，以及（iii）[011]区域轴附近的Rel-Rod CTEM暗场（DF）成像。还研究了STEM收集角度对位错环对比形成的影响。通过对离子辐照的Ni中发现的所有类型为a / 2 <110> {110}和a / 3 <111> {111}的完美和有缺陷环的种群进行成像，证实了所开发的方法₄₀ Fe ₄₀ Cr ₂₀合金。所提出的基于STEM的技术可以容易地识别尺寸大于10nm的所述环，而无需诸如使用常规Rel-Rod CTEM-DF技术通常做出的那些假设。本研究中推荐的方法学被开发为一种快速便捷的工具，由于其常见的晶体学原理，可以普遍应用于基于FCC的辐照材料。