Dresden 2009 – wissenschaftliches Programm

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MM: Fachverband Metall- und Materialphysik

MM 21: Topical Session Nanoporous Functional Materials - Poster

MM 21.4: Poster

Dienstag, 24. März 2009, 14:45–16:30, P4

Nanoindentation and micro-compression testing of nanoporous gold — •Eike Epler¹, T. John Balk², and Cynthia A. Volkert¹ — ¹Institut für Materialphysik, Georg-August-Universität Göttingen — ²Department of Chemical and Materials Engineering, University of Kentucky

Recent studies on materials such as nanoporous Au have shown that the strength of open-cell foams can be increased at a fixed porosity by decreasing the foam length scale (ligament diameter and length). This effect is attributed to the difficulty of activating dislocations in sub-micron crystal volumes. If high strength nanoporous materials are to be used to advantage in technical applications, the details of the parameters determining their strength need to be understood.

In this study, the mechanical response of nanoporous Au fabricated by electrochemical dissolution from a Au-Ag alloy, is investigated by indentation using a cube corner tip as well as by micro-compression testing of columns fabricated by focused ion beam machining. The tests reveal a significant time-dependence or creep behavior in the 30% relative density foam that is not observed in fully dense gold. The origins of this effect will be probed by varying the length scale of the foam. In addition, a large scatter in mechanical behavior, particularly in the elastic response, is observed from position to position and sample to sample, which is attributed to small variations in the open cell structure.