Strength characterization of Al/Si interfaces: A hybrid method of nanoindentation and finite element analysis

A novel hybrid method of nanoindentation and finite element analysis is used to characterize the silicon particle indentation strength and the mechanical properties of Al/Si interfaces in an aluminum matrix composite. The indentation threshold strength is found to be strongly dependent on the aspect ratio, up to 2, of the buried portion of cylindrically shaped particles. The indentation resistance comes from the plastic-flow strength of the matrix and the slip strength of the interface. The interface slips during loading and opens up during unloading. An element-size-dependent finite element cohesive-zone law is used to extract the interface properties; the results compare well with atomistic estimations.