The mechanical behavior during nanoindentation near the grain boundary in a bicrystal FCC metal

This work addresses the hardening effect in close proximity of a grain boundary during nanoindentation experiments. Nanoindentation near the grain boundaries may lead to a detectable slip transfer and can be evaluated quantitatively by resource to a Hall-Petch analysis in terms of dislocation pile-ups at grain boundaries. As a result of the difficulty in slip transmission across the grain boundary, it is possible to measure the intrinsic hardening effect contributed by the grain boundaries with the availability of nanoindentation technique. In order to isolate the grain boundary effect, a bicrystalline face-centered cubic (FCC) aluminum specimen is used. Nanoindentation experiments are performed near the grain boundary with different distances in order to investigate the interaction between dislocations created by the indenter and the grain boundary. Material length scales used in conjunction with gradient plasticity theories are obtained from experimental results of the aluminum bicrystal specimen. Furthermore, numerical simulations are performed using the ABAQUS software.