Can nanoscale twin boundaries serve as dislocation sources in single crystals?

Nanoscale twin boundaries with initial defects are found to be easy dislocation sources in experiments. Here, deformation of nano-twinned single crystals is performed by using atomistic simulations. It is revealed that perfect TBs potentially are not dislocation sources. Another observation is that plastic deformation under uniaxial tensile loading can be dominated by TB migration in samples with inclined TB orientation. Twin planes with disconnections induced by dislocation–TB interactions are obtained during nanoindentation. Under further plastic deformation, it is observed that nucleation of dislocations occur at the disconnections where coherency of TBs has been destroyed.