Prediction and Observation of the bcc Structure in Pure Copper at aΣ3 Grain Boundary

We have used molecular dynamics and simulated annealing to study an asymmetrical $\Sigma 3$ tilt grain boundary with $〈211〉$ rotation axis in Cu. The boundary plane was inclined at 84° with respect to the $\{\}\left(111\right)$ 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.