Elastic and plastic Poisson's ratios of nanoporous gold

We explore the elastic and plastic Poisson's ratios, nu(E) and nu(P), of nanoporous gold, using digital image correlation during compression experiments including load/unload segments. The two coefficients differ significantly, with nu(E) independent of the ligament size, L, and with a trend for nu(P) proportional to L at not too large L. Disorder in the network of ligaments may explain why nu(E) is smaller than predicted by lattice-based models. Finite element simulations, based on the Deshpande-Fleck constitutive law, validate the data analysis. The constitutive law captures work-hardening and transverse flow of nanoporous gold in good agreement with the experiment. (C) 2015 Acta Materialia Inc. Published by Elsevier Ltd.