Dislocation motion-induced strain in nanocrystalline materials: Overlooked considerations

The amount of plastic strain caused by the motion of a single dislocation across an individual nanosize grain is drastically higher than the amount recorded for larger grain sizes. As a result, in nanocrystalline materials, only a small number of dislocations would need to move within each individual grain in order to accommodate the plastic strain on the entire sample. This observation leads to a quantitative criterion for determining if observed dislocation activity is sufficient to accommodate realistic applied plastic strains. This new criterion is directly applicable to the interpretation of in situ TEM experiments and computational molecular dynamics simulations.