Twinning and stacking fault formation during tensile deformation of nanocrystalline Ni

Deformation twins and stacking faults have been observed in nanocrystalline Ni, for the first time under uniaxial tensile test conditions. These partial dislocation mediated deformation mechanisms are enhanced at cryogenic test temperatures. Our observations highlight the effects of deformation conditions, temperature in particular, on deformation mechanisms in nanograins.