Using atomistic simulation, the indentation of single-crystalline Cu was investigated for both an ideal and a stepped (111) surface. Both systems exhibit an intermediate regime of reversible plasticity, characterized by the formation of extended stacking faults, which heal entirely upon withdrawal of the indenter. This regime could be employed to clarify the role of pure stacking fault generation and cross-slip in plasticity. Its existence reveals that, on the atomistic scale, plastic deformation was characterized by material transport rather than by the nucleation of stacking faults. Finally, a criterion was established which was based upon the total displacement of particles-to determine after which indentation depth plasticity was generated irreversibly in the material.

Reversible Plasticity under Nanoindentation of Atomically Flat and Stepped Surfaces of FCC Metals. G.Ziegenhain, H.M.Urbassek: Philosophical Magazine Letters, 2009, 89[11], 717-23