Hardening under compression in Au foams

We report the results of compressive tests for a model bi-continuous nanoporous gold structure using atomistic simulations focusing on the densification regime and the plasticity mechanisms taking place. The stress - strain response follows a logarithmic evolution proportional to the inverse of strain and we provide a simple scaling law for this behavior. Hardening is correlated to the dislocation density and an exponential dependence is revealed. The plasticity mechanisms were inspected revealing the presence of Hirth and Frank partials contributing to the hardening of the sample. Lomer-Cottrel locks, perfect dislocations, and twinning were also found. (C) 2016 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.