Observation of atomic processes in Xe nanocrystals embedded in Al under 1 MeV electron irradiation

Defect introduction processes in two differently sized Xe nanocrystals embedded in Al were observed with in situ high-resolution electron microscopy. The imaging conditions made it possible to follow the apparent movement of Xe atom columns within a nanocrystal. The positions of individual atom columns were measured on captured video images, before and after defect introduction, from intensity traces along the rows of atom columns. For each of these precipitates, a planar defect appears on {1 1 1}. The observed displacement of Xe atom columns approximately corresponds to the projected displacement produced by a Shockley partial dislocation, bounding an intrinsic stacking fault. Comparison of the displacements of atoms in the two nanocrystals shows that the displacements are reduced at the precipitate/matrix interfaces. This implies that there will be a displacement at interfaces that represents some compromise between the strain field of the partial dislocation and the interface compatibility requirement.