PREDICTION AND OBSERVATION OF THE BCC STRUCTURE IN PURE COPPER AT A SIGMA-3 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 degrees with respect to the {111} plane. A simple central force N-body interatomic potential was used. The most stable configuration shows a broadband 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.