Cyclic indentation behavior of metal–ceramic nanolayered composites

The indentation behavior of metal/ceramic nanolayered composites is studied numerically using the finite element method. Attention is devoted to cyclic response under fixed maximum and minimum loads, with the primary objective of examining the evolving plastic deformation in the ductile metal constrained by the hard ceramic layers. The axisymmetric model consists of alternating aluminum (Al) and silicon carbide (SiC) thin films on a silicon (Si) substrate, with the Al/SiC layered structure indented by a conical diamond indenter. It is found that, unlike the homogeneous material where indentation unloading consists of purely elastic recovery, in the multilayered material plastic deformation in the Al layers continues to occur upon unloading and subsequent loading/unloading operations. With each additional cycle the indenter penetrates deeper into the composite. The modeling results are in qualitative agreement with the actual cyclic nanoindentation experiment conducted on the Al/SiC nanolayers.