Limits of detectability for clusters and solute segregation to grain boundaries

The abilities to detect and characterize the sizes and distribution of solute clusters, embryos, precipitates and solute atoms in the matrix by friends-of-friends methods in atom probe tomography are shown to improve with single atom position-sensitive detectors with high detection efficiency. In low solute matrices, clusters with as few as 5 atoms can be detected. A characterization method is presented that enables complete characterizations of grain boundaries and triple junctions by atom probe tomography in terms of the orientation relationships of the adjacent grains, as well as the local variations of the habit plane, surface curvature, and the solute excesses over the surface of a grain boundary with up to a 1 nm by 1 nm spatial resolution.