The core structure of 60° mixed basal dislocation in alumina (α-Al2O3) introduced by in situ TEM nanoindentation

The dislocation associated with the (0001)1/3<11<(2)over bar>0> basal slip in alumina plays an important role on its plastic deformation at elevated temperatures. A 60 degrees mixed basal dislocation was preferentially introduced by in situ transmission electron microscopy (TEM) nanoindentation, and characterized by atomic-resolution scanning TEM (STEM). It was revealed that the 60 degrees mixed basal dislocation dissociates into two partial dislocations via self-climb with a stacking fault on the {1 (1) over bar 00} plane. The dissociation mechanisms of the basal dislocation have been discussed in terms of its core structure and atomic diffusion process. (C) 2019 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.