Numerical analysis of plastic deformation in metal-ceramic nanolayers during cyclic indentation
The indentation behavior of metal/ceramic nanolayered composites is studied nu- merically 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. An axisymmetric model consisting of alternating aluminum (Al) and silicon carbide (SiC) thin films on a silicon (Si) substrate is indented by a conical diamond indenter. In this study, both rate-independent and rate-dependent plasticity models are considered. It is found that, in the multilayered material plastic deformation in the Al layers continues to occur upon unloading and subsequent loading /unloading operations. The cyclic plasticity results in an open load-displacement loop, and the indenter continues to move deeper with each cycle. For the control model of a homogeneous Al film, there is no hysteresis loop and transient behavior soon approaches stabilization, showing repetitive elastic loading/unloading. The modeling results are also compared with cyclic nanoindentation experiments conducted on the same metal-ceramic multilayer system and control specimen. The modeling results are in qualitative agreement with the actual cyclic nanoindentation experiment conducted on the Al/SiC nanolayers.
nanoindentation, ABAQUS, Deformation (Mechanics), Plasticity, Nanocomposites (Materials)
Networked Digital Library of Theses and Dissertations