Three-dimensional visualization of dislocation-precipitate interactions in a Al–4Mg–0.3Sc alloy using weak-beam dark-field electron tomography

Weak-beam dark-field images of dislocations interacting with particles acquired over a large angular range were used to reconstruct tomograms, which were then used as the basis to construct a three-dimensional (3D) model of the dislocation structure. These capabilities facilitate viewing the dislocation structure from different directions, recovering the information lost in the electron beam direction. Coupling these capabilities and a method to include the specimen coordinate system within them with conventional dislocation analysis enables a full characterization of the dislocation microstructure in three dimensions. This approach is used to understand the 3D nature of the interaction of dislocations and a twist boundary with Al3Sc particles in an Al–Mg–Sc alloy.