Atomistic mechanisms of microstructure evolution in nanotwinned polycrystals

Deformation of nanotwinned polycrystals subjected to uniaxial tensile loading is investigated by using massive parallel atomistic simulations. The following atomistic mechanisms associated with microstructure evolution are obtained: (i) formation and rotation of nanosized subgrains due to intensive dislocation – twin boundary interactions in nanotwinned grains; (ii) transformation of a specially orientated nanotwinned grain from a regular hexagonal shape to a rectangular shape; and (iii) thickening of a twin lamella controlled by grain boundary migration.