Discrete dislocation simulation of nanoindentation: The effect of statistically distributed dislocations

Nanoindentation is simulated by the motion of statistically distributed discrete dislocations on slip bands parallel to the free surface. We do not allow any dislocation emission from sources in our simulations and show that even under these drastically simplified conditions it is possible to obtain an indentation size effect. The level of decrease of the hardness with increasing indentation depth is shown to be mainly affected by the amount of pre-existing dislocations in the model material and by the lattice friction stress. It is verified that the hardness is much higher than that of a solid, containing dislocation sources.