Differences in deformation processes in nanocrystalline nickel with low- and high-angle boundaries from atomistic simulations

Molecular dynamics simulations show significant differences in the deformation mechanisms of nanocrystalline nickel with low- and high-angle boundaries. For the case studied with average grain size of 12 nm, low-angle boundaries present enhanced dislocation activity and reduced strength with respect to high-angle boundaries for low strains. In the latter, most of the deformation is accommodated at the grain boundaries with limited dislocation activity, while in the case of low-angle boundaries, most of the displacements observed are associated with the motion of partial dislocations nucleated at the grain boundaries.