Partial-dislocation-mediated processes in nanocrystalline Ni with nonequilibrium grain boundaries

The partial-dislocation-mediated processes have so far eluded high-resolution transmission electron microscopy studies in nanocrystalline (nc) Ni with nonequilibrium grain boundaries. It is revealed that the nc Ni deformed largely by twinning instead of extended partials. The underlying mechanisms including dissociated dislocations, high residual stresses, and stress concentrations near stacking faults are demonstrated and discussed.