Subsurface nanoindentation deformation of Cu-Al multilayers mapped in 3D by focused ion beam microscopy

A new technique for the three-dimensional analysis of subsurface damage of nanocomposites is presented. Cu-Al multilayers, grown epitaxially on (0001) Al2O3 single crystals by ultra high vacuum molecular beam epitaxy, have bee n deformed by nanoindentation. Systematic slicing and imaging of the deform ed region by focused ion beam microscopy enables a 3D data set of the damag ed region to be collected. From this 3D data set, profiles of the deformed sub-surface interfaces can be extracted. This enables the deformation of th e individual layers, substrate and overall film thickness to be determined around the damage site. These 3D deformation maps have exciting implication s for the analysis of mechanical deformation of nanocomposites on a sub-mic rometre scale.