Elastic properties of metal-ceramic nanolaminates measured by nanoindentation

The elastic modulus of metal-ceramic nanolaminates measured by nanoindentation was studied experimentally and numerically. A model system of seven layers of alternating aluminum (Al) and silicon carbide (SiC) films deposited on a silicon (Si) substrate was used. The variation of elastic modulus, measured from the indentation unloading, as a function of layer thickness and indentation depth was investigated. Finite element modeling, featuring indentation of the explicit composite structure, was conducted and shown to be in good agreement with the experiment. The numerical result offered further insight into the detailed deformation processes. The effects of the substrate material and pile-up at the indentation edge were seen to play an important role in the modulus determination. Sophisticated stress and deformation fields underneath the indentation developed in the laminated structure. Their evolution during the unloading phase of the indentation was also examined. Salient features which can affect the modulus measurement were discussed.