Prediction and Observation of the bcc Structure in Pure Copper at a Σ3 Grain Boundary

We have used molecular dynamics and simulated annealing to study an asymmetrical Σ3 tilt grain boundary with ⟨211⟩ rotation axis in Cu. The boundary plane was inclined at 84° with respect to the {}(111) plane. A simple central force N-body interatomic potential was used. The most stable configuration shows a broad band of predominantly bcc structure in the boundary region. Samples of the bicrystal with the same misorientation and inclination of the boundary plane were observed in a 1250 kV transmission electron microscope, confirming the predicted structure with atomic resolution.