A continuum plasticity model that accounts for hardening and size effects in thin films

Abstract

We conducted three-dimensional finite element simulations of the mechanical response of passivated single crystal copper thin films with a continuum crystal plasticity model. The model introduces the formation of high density dislocation layers close to the substrate and passivation interfaces obtained from dislocation dynamics simulations. These dislocation structures are responsible for an increase in strain hardening as the film thickness decreases. The model predicts an increase in strain hardening as the film thickness decreases in agreement with experimental observation in films with thickness in the range 0.2 to 2 µm.