From micro- to macroplasticity

The microplastic regime, where materials exhibit plastic deformation at stresses well below the yield stress, is of great importance for the precise design of functional materials. In polycrystalline metals, it is taken for granted that the majority of grains are plastically deforming at the macroscopic yield stress; however, there is no easy method to verify this assumption. The figure shows that for electrodeposited nanocrystalline Ni the usual 0.2 % definition of yield stress does not correspond with the onset of macroscopic plasticity.