Australian Centre for Microscopy and Microanalysis, The University of Sydney, Sydney, Australia.
Ultramicroscopy. 2011 May;111(6):435-9. doi: 10.1016/j.ultramic.2010.12.005. Epub 2010 Dec 15.
The random sampling provided by classical atom probe sample preparation methods is one of the major factors limiting the types of problems that can be addressed using this powerful technique. A focused ion beam enables not only site-specific preparation, but can also be used to give the specimen, which acts as the lens in an atom probe experiment, a specific shape. In this paper we present a technique that uses low accelerating voltages (10 and 5 kV) in the focused ion beam (FIB) to reproducibly produce specimens with selected grain boundaries <100 nm from the tip at any desired orientation. These tips have a high rate of successfully running in the atom probe and no Ga contamination within the region of interest. This technique is applied to the analysis of grain boundaries in a high purity iron wire and a strip-cast steel. Lattice resolution is achieved around the boundary in certain areas. Reconstruction of these datasets reveals the distribution of light and heavy elements around the boundary. Issues surrounding the uneven distribution of certain solute elements as a result of field-induced diffusion are discussed.
经典原子探针样品制备方法提供的随机抽样是限制使用这种强大技术解决问题类型的主要因素之一。聚焦离子束不仅可以进行特定位置的制备，还可以用于赋予作为原子探针实验透镜的样品特定的形状。在本文中，我们提出了一种使用低加速电压（10 和 5 kV）在聚焦离子束（FIB）中重复制备具有选定晶界的样品的技术，这些晶界距离尖端在任何所需方向上均小于 100 nm。这些尖端在原子探针中成功运行的速度很快，并且在感兴趣区域内没有 Ga 污染。该技术应用于高纯铁丝和钢带铸造钢中晶界的分析。在某些区域实现了边界周围的晶格分辨率。这些数据集的重建揭示了边界周围轻元素和重元素的分布。讨论了由于场诱导扩散导致某些溶质元素不均匀分布的问题。
