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MM: Fachverband Metall- und Materialphysik
MM 60: Nanomaterials IV - Deformation and mechanical properties
MM 60.1: Talk
Thursday, April 3, 2014, 15:45–16:00, IFW B
Deformation of nanoporous gold: the importance of topology — •Bao-Nam D. Ngo1,3, 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
We present a molecular dynamics study on the influence of the topology on the mechanical properties of nanoporous gold. Following a suggestion by N. Huber et al. [1], we study a highly symmetric diamond-like structure and compare it to a disordered structure, both having comparable relative density, feature size, and surface area. The random sample shows zero lateral expansion to a certain point under compression and noticeable lateral contraction in tension. Plasticity happens immediately upon compression, followed by strain hardening of material due to dislocation activity. In line with continuum modeling, the symmetric structure shows appreciable lateral strain in both compression and tension. It also shows clear elasticity before yielding, with similar elastic modulus in both test modes. Appreciable dislocation activity in compression is observed only at very large strain. Other relevant mechanical properties are also investigated, suggesting that topology can strongly affects nanoporous mechanical behavior.
[1] N. Huber et al., Scaling Laws of Nanoporous Metals under Uniaxial Compression; in preparation (2013).