High-resolution electron microscopy study of the (1012) twin and defects analysis in deformed polycrystalline alpha titanium

A (1012) twin boundary in deformed alpha-Ti has been observed by highresolution electron microscopy. The observations are in agreement with a model calculated using a many-body potential. A twinning dislocation is predicted by the topological theory and characterized directly in the experimental image with the circuit mapping method. It is shown that the core defect is spread along the twin plane as predicted by the atomistic model. Finally, the observation of a large step associated with a dislocation with Burgers vector b10/9 points to the mechanism of matrix dislocation decomposition in the twin boundary.