Using multi-scale simulations, the influence of both smooth and atomically rough indenter tips upon the nucleation of dislocations during nano-indentation of single-crystal Al was explored. The long-range strain with finite element analysis was modelled using anisotropic linear elasticity. A region near to the indenter was then modelled atomistically and molecular dynamics were performed with an embedded atom method interatomic potential. It was found that smooth indenters nucleated dislocations below the surface, but rough indenters could nucleate dislocations both at the surface and below. Increasing the temperature from 0 to 300K created pre-nucleation defects in the region of high stress, and decreased the critical depth.

Dislocation Nucleation during Nanoindentation of Aluminium. R.J.Wagner, L.Ma, F.Tavazza, L.E.Levine: Journal of Applied Physics, 2008, 104[11], 114311