ABSTRACT
The load displacement curves obtained during a nanoindentation experiment may show discontinuities or steplike features at load levels typically well below 1 mN that characterize a sharp transition from purely elastic to plastic deformation. These are called pop-in events. The pop-in behavior is most often attributed to the nucleation of dislocations and the onset of incipient nanoscale plasticity. The reasons behind their genesis are still far from well understood. So what we propose to do is this: We first present the literature scenario of pop-ins in ceramics in particular and other materials in general. Then we look at our own experimental observations.
