Lawitzki Robert, Stender Patrick, Schmitz Guido
Institute of Materials Science, Department of Materials Physics, Universität Stuttgart, Heisenbergstraße 3, D-70569Stuttgart, Germany.
Microsc Microanal. 2021 Mar 16:1-12. doi: 10.1017/S1431927621000180.
Local magnification artifacts in atom probe tomography (APT) caused by multiphase materials with heterogeneous evaporation behavior are a well-known problem. In particular, the analysis of the exact size, shape, and composition of small precipitates is, therefore, not trivial. We performed numerical simulations of APT measurements to predict the reconstructed morphology of precipitates with contrasting evaporation thresholds. Based on a statistical approach that avoids coarse graining, the simulated data are evaluated to develop a model for the calculation of the original size of the precipitates. The model is tested on experimental APT data of precipitates with a higher and lower evaporation field in a ferritic alloy. Accurate sizes, proven by a complementary investigation by transmission electron microscopy, are obtained. We show further, how the size information can be used to obtain compositional information of the smallest precipitates and present a new methodology to determine a correct in-depth scaling of the APT reconstruction in case no complementary geometric information about the specimen exists or if no lattice planes are visible in the reconstruction.
由具有非均匀蒸发行为的多相材料导致的原子探针断层扫描（APT）中的局部放大伪像，是一个众所周知的问题。因此，特别地，对小析出物的确切尺寸、形状和成分进行分析并非易事。我们进行了APT测量的数值模拟，以预测具有不同蒸发阈值的析出物的重建形态。基于一种避免粗粒化的统计方法，对模拟数据进行评估，以建立一个计算析出物原始尺寸的模型。该模型在铁素体合金中具有较高和较低蒸发场的析出物的实验APT数据上进行了测试。通过透射电子显微镜的补充研究证实，获得了准确的尺寸。我们进一步展示了如何利用尺寸信息来获取最小析出物的成分信息，并提出了一种新方法，在不存在关于样品的补充几何信息或重建中看不到晶格平面的情况下，确定APT重建的正确深度缩放。
