Indentation Size Effect on Hardness of Nanostructured Thin Films
Based on nanoindentation techniques, the evaluation of hardness of two nanostructured thin films, AlN and Ti-Al-N, is discussed. In the case of AlN films, the indentation size effect of hardness can be modeled using the concept of geometrically necessary dislocations, whereas in the case of Ti-Al-N films, the measured hardness increases exponentially as the indentation depth decreases. The results show that, as thin films approach superhard, dislocation-based plastic deformation is gradually replaced by grain-boundary mediated deformation.
Hong-Yuan Liu, Xiaozhi Hu and Mark Hoffman
C. S. Lu et al., "Indentation Size Effect on Hardness of Nanostructured Thin Films", Key Engineering Materials, Vol. 312, pp. 363-368, 2006