Formation of surface roughness on nanocrystalline aluminium samples under straining by molecular dynamics studies

Abstract

The surface roughening of nanocrystalline aluminium samples was investigated by molecular dynamics simulations. Attention was focused on the fact that roughness increases with the grain size and the strain. The elastic–plastic transition was found at around 3.5% strain and a reverse Hall–Petch effect was observed under straining conditions. Then, different strain distributions in grains and grain boundaries at the sample surface were highlighted, yielding to the formation of local roughness. Finally, a linear relationship between the magnitude of roughness and the out-of-plane strain component was found.

Acknowledgements

We would like to thank the CRI from the University of Burgundy for allowing us to access their computer facilities. The authors are deeply grateful to D. Kempf and A. Hasnaoui for fruitful discussions.