Indentation mechanics and fracture behavior of metal/ceramic nanolaminate composites

Composite laminates on the nanoscale have unique properties, such as high strength, high wear resistance, and biocompatibility. In this paper we report on the nanoindentation behavior of a model metal-ceramic nanolaminate consisting of alternating layers of aluminum and silicon carbide (Al/SiC) processed by PVD on a Si substrate. Composites with different layer thicknesses were fabricated and the effect of layer thickness on Young's modulus and hardness was quantified. The effect of indentation depth on modulus and hardness was studied. The damage that took place during nanoindentation was examined by cross-sectioning the samples by focused ion beam (FIB) technique and imaging the surface using scanning electron microscopy (SEM). Finite element modeling (FEM) of nanoindentation of nanolaminates was conducted. The damage patterns observed in experiments were qualitatively supported by the numerical simulations.