Published online by Cambridge University Press: 14 March 2011
Former molecular dynamics computer simulations of polycrystalline Ni and Cu metals with mean grain sizes ranging between 3 and 12 nm demonstrated a change in deformation mechanism as a function of grain size: at the smallest grain sizes all deformation is accommodated in the grain boundaries. In this paper we report on the influence of the presence of two free surfaces on the deformation behaviour. The purpose of this simulation is to study which phenomena observed in in-situ tensile experiments performed in the electron microscope can be expected to be intrinsic properties of the deformation process and which phenomena are due to the presence of two free surfaces separated by a very small distance.