Discrete dislocation simulation of nanoindentation: the influence of obstacles and a limited number of dislocation sources

Nanoindentation is simulated on the computer by means of a 2D discrete dislocation model under the conditions of a constrained geometry. First, an indentation test near a grain boundary is investigated by the arrangement of only one boundary and second, an indentation test into the center of the surface of a small grain (lamella) is mimicked by the arrangement of two boundaries. The effect of a limited number of dislocation sources is studied by the simulations of an indentation test in a plastically deformable film on an ideal elastic substrate and by such tests on an ideal elastic film on a plastically deformable substrate. The discrete nature of plasticity is shown to have a significant influence on the mechanical material behavior in all our investigations.