Atomic simulations of dislocation emission from Cu/Cu and Co/Cu grain boundaries

Molecular dynamics simulations of creep tests have been performed on Cu/Cu single-phase bicrystals and Co/Cu two-phase bicrystals to investigate the dislocation emission from grain boundaries. In the Co/Cu bicrystals, both E structures and stacking faults were generated only in the Cu grain near the boundary. Dislocations were emitted only from the stacking faults, not from the E structures, in the Co/Cu bicrystals. The stacking faults in the Co/Cu bicrystals did not necessarily enhance the dislocation emission as readily as those in the Cu/Cu bicrystals. The incoherence between Co and Cu gave rise to the complicated defect structures at and near the Co/Cu boundary, and thus distinctive atomic shuffling mechanisms occurred. This affected the dislocation emission behavior of the Co/Cu bicrystals.

Research highlights▶ Co/Cu bicrystals have both E structures and stacking faults only in the Cu phase. ▶ Dislocations tend to be emitted from the stacking faults in Co/Cu bicrystals. ▶ Large disorder around the stacking faults accelerates the atomic shuffling. ▶ Atomic shuffling behavior strongly affects dislocation emission in Co/Cu bicrystals.