Approaching the theoretical strength in nanoporous Au

The mechanical properties of nanoporous Au have been investigated by uniaxial compression. Micron-sized columns were machined in the surface of nanoporous Au using a focused Ga+ beam and compressed with a flat punch in a nanoindenter. Using scaling laws for foams, the yield strength of the 15 nm diameter ligaments is estimated to be 1.5 GPa, close to the theoretical strength of Au. This value agrees well with extrapolations of the yield strength of submicron, fully dense gold columns and shows that in addition to foam density and structure, the absolute size of ligaments and cell walls can be used to tailor foam properties. (c) 2006 American Institute of Physics.