Deformation Twinning in Nanocrystalline NI

Deformation twinning is observed upon large plastic deformation in nanocrystalline (nc) Ni by transmission electron microscopy examinations. New and compelling evidence has been obtained for several twinning mechanisms that operate in nc grains, with the gain boundary emission of partial dislocations determined as the most proficient. Deformation twinning in nc Ni is discussed in comparison with molecular dynamics simulation results, based on generalized planar fault energy curves.