Determination of the formation energy of edge, screw and twinning dislocations in fcc metals using the molecular dynamics

A method is proposed for determining the energy of moving edge, screw, and twinning dislocations in fcc metals using molecular dynamics, which consists in constructing and analyzing the graph of the time dependence of the potential energy of the calculation area of the crystal through which the dislocation passes. Nickel, copper, silver, and austenite are considered as examples of fcc metals. The initiation of the formation and movement of a dislocation was carried out by simulating a shear at a constant rate from the end of the computational cell. It was found that the shear rate above about 40 m/s affects the energy of dislocation: with increasing rate, the energy of the dislocation increases. According to the data obtained, the energy of an edge dislocation is approximately one and a half times higher than the energy of a screw dislocation. The energy of a twinning dislocation is much less than the energy of edge and screw dislocations. The moving twinning dislocation in the model was obtained as a result of the splitting of a screw dislocation on the twin into two partial dislocations that slide along the twin after splitting.