Evidence of a two--dimensional grain sliding regime in the plastic   deformation of micron and sub--micron films
  Copper and aluminium sub-micron films are structured as columnar arrays of grains traversing the entire film, and hence are virtual two-dimensional polycrystalline solids. A closed-form solution for the two-dimensional plastic flow is obtained assuming that grain boundary sliding is the dominating mechanism for deformation. The theoretical results obtained here are in close agreement with experimental data appeared in the literature, which suggests further work on the subject. 
Miguel Lagos, V\'ictor Conte and Michel Ignat
cond-mat.mtrl-sci cond-mat.soft