Implementation of New Boundary Condition in LAMMPS for Energetics of Screw Dislocation in BCC Iron

Abstract

Accurate investigation of the energetics of screw dislocation in body-centered cubic iron is important for strength evaluation of steel materials. For accurate atomic modeling of screw dislocations due to the long-range elastic interac-tions produced by dislocations, it is important to establish atomic models and boundary conditions. Recently, Helicoidal Boundary Conditions (HBCs), a new treatment of boundary conditions for screw dislocations in cubic metal, have been proposed by Savvidi et al. In this study, we implemented HBCs in LAMMPS as fix function. We also investigated the energetics of screw dislocations in BCC iron under HBCs. The Peierls barrier and Peierls stress predicted by our developed artificial neural network potential are 36.9 meV/b and 1440MPa, where b in magnitude of Burgers vector, respectively. These results are consistent with previous studies and allow us to confirm the advantages of HBCs.