L. Priester

On the interactions between dislocations and a near-Σ=3 grain boundary in a low stacking-fault energy metal

The interactions of dissociated lattice dislocations with a near-Σ = 3 grain boundary (GB) in copper have been investigated by transmission electron microscopy using the weak-beam technique combined with bright-field image matching. From our observations, Shockley partials are required to recombine when entering the GB to form an absorbed perfect lattice dislocation. Then, decomposition of the latter into two displacement shift complete (DSC) products occurs. Complex reactions between DSC dislocations yield further stress relaxation. The role of the stacking-fault energy in the dislocation–GB interactions is pointed out.

Extended interfacial structure between two asymmetrical facets of a Σ = 9 grain boundary in copper

Abstract The presence of an extended structure in a Σ = 9 grain boundary of copper has been highlighted by high-resolution transmission electron microscopy. The phase, located in a grain boundary region between two different asymmetrical facets, may be described as a three dimensional phase with a hexagonal structure. A detailed analysis of the defects at the limits between the phase and the two copper crystals allows us to propose an interpretation for the occurrence of this local phase transformation.