Molecular Dynamics Simulation on the Nanoindentation Behavior of a Copper Bilayered Thin Film

Understanding the mechanical properties of multilayered metal thin films is very important for their applications in nanoscale devices. Nanoindentation is one of the widely used tools for examining the mechanical properties of metal thin films. In the present study, molecular dynamics simulation was employed to investigate the nanoindentation behavior of a Cu(100)/Cu(110) bilayered thin film. The load-displacement response and the detailed deformation structure of the copper thin film during the nanoindentation were inspected and compared with those of Cu(100) and Cu(110) thin films. It was found that at the indenting stage the maximum indentation load of the bi-layered thin film is lower than that of its ingredients, however, they have nearly the same maximum indentation load. At the retracting stage, the maximum attractive force of the bilayered thin film was found near that of its ingredients but occurred much earlier than the ingredients. The detailed deformation structure of the bilayered thin film was observed to be similar to that of the ingredients and correlated very well with the load-displacement response.