Regensburg 2013 – scientific programme
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MM: Fachverband Metall- und Materialphysik
MM 55: Nanomaterials - Nanocrystalline & Porous Materials II
MM 55.2: Talk
Thursday, March 14, 2013, 12:00–12:15, H25
Molecular dynamics study of nanoporous gold deformation — •Bao-Nam D. Ngo1,2, Karsten Albe2, and Jörg Weissmüller1,3 — 1Institut für Werkstoffforschung, Werkstoffmechanik, Helmholtz-Zentrum Geesthacht, Geesthacht, Germany — 2Technische Universität Darmstadt, Fachbereich Material- und Geowissenschaften, Fachgebiet Materialmodellierung, Darmstadt, Germany — 3Institut für Werkstoffphysik und Werkstofftechnologie, Technische Universität Hamburg-Harburg, Hamburg, Germany
Nanoporous gold made by dealloying is under discussion for applications in actuation, catalysis, and sensing. The material is also a model system for deformation processes in nanomaterials. While early experiments suggest that nanoporous gold is brittle, recent studies reveal its ductile behavior in compression test, with many striking observations, such as a yield strength lower than what is expected from scaling law, nearly zero transverse plastic flow, and extremely high strain hardening coefficients. Here, we report a molecular dynamics study of the deformation of nanoporous gold, focused on uniaxial compression tests. Computer samples are prepared by spinodal decomposition. In agreement with experiment, they show ductile behavior with low yield stress, very small transverse plastic strain, and an extended elastic-plastic transition region in the stress-strain curve. The underlying deformation mechanisms and dislocation activity are investigated.