A new view of the onset of plasticity during the nanoindentation of aluminium

A new view of the onset of plasticity during the nanoindentation of aluminium, is presented. The views on the onset of plasticity during nanoindentation are based solely on indirect evidence and idealized computational simulations. The onset of plasticity is investigated by using quantitative in situ nanoindentation in a JEOL 3010 transmission electron microscope (TEM) to directly correlate the onset of plasticity with dislocation activity. In situ nanoindentation has been used to explore initial deformation modes in aluminium thin films, and attempts have been made to correlate load-displacement behavior with real-time images of the deformation response. The observations of the onset of plasticity occurring before a sustained rise in repulsive force challenge many previous conclusions regarding nanoindentation pop-in/load-drop behavior.