3D shape and orientation of nanoscale Pb inclusions at grain boundaries in Al observed by TEM and STEM tomography

摘要

We have combined high-angle annular dark field/scanning transmission electron microscopy (HAADF-STEM) tomography with bright field (BF)-TEM tomography to characterize small inclusions of Pb at a grain boundary in Al. It was found that the shape of the grain boundary inclusions is more complex than previously thought. By using moire fringes observed at some orientations of the specimen in a BF-TEM tomographic tilt series, we were able to determine the orientation of each grain, the axis and angle of misorientation of the grain boundary, and the facet planes of the grain boundary inclusions. The 3D shape of the inclusions was determined by merging this information with the HAADF-STEM tomography.