Atomic positions from high resolution transmission electron microscopy images of grain boundaries
Laboratoire de Thermodynamique et de Physico-Chimie Métallurgiques, UMR 5614 CNRS-INPG/UJF ENSEEG, BP75, F-38402 Saint Martin d’Heres, France
Abstract
High resolution transmission electron microscopy images are constituted by diffuse spots which correspond to atomic columns of the observed crystal. In the case of grain boundaries including defects, the atomic positions accounting for the elastic distorsions of the crystals can be calculated. In order to compare calculated and experimental positions, it is necessary to extract the "centers" of the spots from experimental images. A simple method is proposed here, involving two steps: first, the identification of spot Zones, with individual masks, then calculation of intensity weighed center of each spot inside each mask. The method was tested on a simple image and applied on a Ni3Al-Ni3Nb grain boundary, showing satisfactory agreement between predicted and experimental atomic positions.