Indentation behavior of metal-ceramic multilayers at the nanoscale: Numerical analysis and experimental verification

The behavior of aluminum/silicon carbide nanolayered composite in response to nanoindentation loading is studied. The effects of heterogeneity on the deformation fields, as well as the hardness and elastic modulus obtained from indentation, are investigated using finite element analysis. Attention is also devoted to correlating the numerical results with experimental deformation and damage features. The model uses an explicit layered structure within the axisymmetric framework. It is found that the nanolayered composite results in unique deformation patterns. Significant tensile stresses can be generated locally along certain directions, which offers a mechanistic rationale for the internal cracking observed experimentally. The unloading process also leads to an expansion of the tension-stressed area, as well as continued plastic flow in parts of the aluminum layers. Comparisons of hardness and indentation-derived modulus between modeling and experiments also point to the importance of incorporating the detailed geometric features when performing indentation analyses.