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MM: Fachverband Metall- und Materialphysik
MM 20: Topical Session: Nanomechanics of nanostructured materials and systems IV - Tribology/Composites
MM 20.3: Talk
Tuesday, April 1, 2014, 11:00–11:15, IFW A
Nanoporous gold - polymer composites with strength and conductivity — •Ke Wang1 and Jörg Weissmüller1,2 — 1Institut für Werkstoffphysik und Werkstofftechnologie, Technische Universität Hamburg-Harburg, Hamburg, Germany — 2Institut für Werkstoffforschung, Werkstoffmechanik, Helmholtz-Zentrum Geesthacht, Geesthacht, Germany
Nanoporous metal synthesis via dealloying provides mm- or cm-sized monolithic samples consisting of a homogeneous network structure of nanoscale "ligaments" with uniform size that can be controlled down to below 10 nm. The strength of the ligaments increases with decreasing size, attaining the theoretical strength at ligament diameters in the lower nanometer region. Here, we explore a novel materials design strategy that combines this high-strength and uniform metallic network structure with an interpenetrating polymer phase to obtain a strong, lightweight composite material. The porous metal was vacuum-impregnated with epoxy resin and tested for microhardness, macroscopic tensile and compressive stress-strain behavior. The results demonstrate that impregnation with a polymer is an efficient way of reducing the density change during plastic flow under uniaxial load. The composite is ductile in tension and compression, its strength considerably exceeds that of each of the constituent phases, and its electric conductivity reaches 1% of that of high-purity massive copper. The finding validates a novel materials design strategy that exploits the trend of "smaller is stronger" in metal nanostructures by incorporating them as reinforcement into a bulk composite material.