Indentation behavior of multilayered thin films: Effects of layer undulation

The behavior of aluminum/silicon carbide multilayered thin films in response to nanoindentation loading is studied. The effect of undulating layer geometry on indentation derived hardness and modulus, and stress/strain field development, is investigated using the finite element method. Two regular waveforms that are 180° out-of-phase are used to represent the undulating features of the SiC layers. The derived hardness and modulus are shown to be sensitive to the undulating layers and the phase of the waveform used to describe these layers. Undulating layers create bands of tensile and compressive axial stress that is significantly different from the flat layers. The amount of equivalent plastic strain in the Al layers is increased. Lastly, the unloading-induced plasticity in the Al layers is amplified with the presence of undulating layers.