TEM measurement of nanoindentation plastic zones in Ni3Al

Nanoindentation tests were performed on Ni3Al and the dense dislocation zones underneath the nanoindents were examined by transmission electron microscopy. The size of these dense dislocation zones was found to be significantly larger than the Oliver–Pharr contact size especially at small indentation depths. The results support an earlier suggestion that the densely dislocated core of a nanoindent relaxes to give rise to a reduction of the measured hardness from the simple Nix–Gao prediction.