Regensburg 2013 – wissenschaftliches Programm
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MM: Fachverband Metall- und Materialphysik
MM 55: Nanomaterials - Nanocrystalline & Porous Materials II
MM 55.3: Vortrag
Donnerstag, 14. März 2013, 12:15–12:30, H25
Elastic and plastic behavior of nanoporous gold as a function of the surface state — •Nadiia Mameka1, Jürgen Markmann1,2, and Jörg Weissmüller1,2 — 1Helmholtz-Zentrum Geesthacht, Institut für Werkstoffforschung, Werkstoffmechanik, 21502 Geesthacht, Germany — 2Technische Universität Hamburg-Harburg, Institut für Werkstoffphysik und -technologie, 21073 Hamburg, Germany
Nanoporous metal is a bicontinuous network of nanoligaments interpenetrated by an open pore space. It exhibits an extremely high specific surface area, which is accessible to electric signals, that afford the surface properties tuning. In this way, the macroscopic materials behavior can be reversibly modified. Here, we report an in situ study on mechanical properties of bulk nanoporous gold infiltrated with electrolyte. The metal-liquid interface properties were controlled via the electrode potential, E. This allowed reversible variations between 1) adsorbate-covered and bare or 2) electrically charged and charge-neutral surface states. The environmental control was implemented in a dynamic mechanical analyzer (DMA) and mechanical testing machine, and revealed large reversible cyclic changes of the effective elastic modulus and flow stress. The results advertize a role of two higher derivatives of the surface free energy function ψ(E,e) where e denotes the strain. The parameter d2ψ/de2 represents an excess elastic constant of the surface. The potential dependence of this behavior, probed in our DMA experiments, relates to the third derivative, d3ψ/(de2dE). Our data present first evidence for this quantity and support the notion of tuning the elasticity and plasticity via the applied electric potential.