Dresden 2006 – wissenschaftliches Programm
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MM: Metall- und Materialphysik
MM 37: Nanostructured Materials I
MM 37.5: Vortrag
Donnerstag, 30. März 2006, 15:45–16:00, IFW D
Self deformation during dealloying of silver-gold alloys — •Smrutiranjan Parida1, Dominik Kramer1, and Joerg Weissmueller1,2 — 1Forschungszentrum Karlsruhe, Institut für Nanotechnologi, Karlsruhe — 2Universität des Saarlandes, Fachrichtung Technische Physik, Saarbrücken
Dealloying or selective dissolution is an important route to prepare nanoporous metals and alloys. We present a study of the dealloying process in silver-gold alloys, which uses SEM, TEM and XRD investigations of the obtained porous metals and measurements of the lateral shrinkage of the sample during dealloying by insitu dilatometry. This shrinkage, which depends on the dissolution rate (hence on dealloying potential) and the composition of the alloy, has not been reported before. The volume of the sample reduces by up to 30% during dealloying, although our measurements show that the original crystal lattice of the alloy is conserved. This result can not be explained with the existing model or with elastic lattice strain or with lattice parameter differences. Therefore, we suggest plastic deformation to explain the observation, which is consistent with the high defect concentration in dealloyed structure as observed by TEM. Several possible mechanisms to nucleate the defects during dealloying are discussed.