Nanoindentation characterization of deformation and failure of aluminum oxynitride

A systematic study of the mechanical deformation and failure of transparent ceramic aluminum oxynitride (AlON) has been conducted using a depth-sensitive nanoindentation technique combined with transmission electron microscopy (TEM) and Raman spectroscopy. Although discrete displacement bursts appear in the load–depth profiles at high applied forces, a detectable high-pressure phase transition has not been found by means of micro-Raman spectroscopy and TEM. Instead, a high density of dissociated h1 1 0i dislocations can be observed underneath the nanoindenters, suggesting that extensive plastic deformation takes place in the brittle ceramic at high contact pressures. Moreover, nanoindentation-induced micro-cracks oriented along well-defined crystallographic planes can also be observed, consistent with the low fracture toughness of AlON evaluated by an indentation method using Laugier’s equation. 2010 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.