Interaction between lattice dislocations and low-angle grain boundaries in Ni via molecular dynamics simulations

Low-angle grain boundaries (LAGBs) may show up frequently as distinct dislocation products such as in the processes of work hardening, recovery and recrystallisation of metals and alloys. To reveal their mechanical behaviours, interactions between lattice dislocation and symmetric tilt and twist LAGBs are studied with molecular dynamics simulations. It is shown that dislocation reaction and slip transmission depend on the structure of LAGB, the character of incident dislocation and the particular glide planes inhabiting the incoming slip. For tilt LAGBs, a free slip-transmission process is identified where dislocations can be forced to penetrate through the boundary without inducing dislocation reaction. Otherwise, the incident slip tends to be trapped or absorbed by those intrinsic grain boundary dislocations. With increasing the applied strain, a number of dislocation reactions can be triggered, which may lead to indirect slip transmission across the boundary.