Effect of lattice defects on the plastic Poisson's ratio of nanoporous gold

LX Cao and Z Zeng and FF Fan, SCRIPTA MATERIALIA, 185, 175-180 (2020).

DOI: 10.1016/j.scriptamat.2020.03.046

Nanoporous gold (np-Au) exhibits variations in the value of the plastic Poisson's ratio, nu(p) - ranging from negative to positive - often for similar relative densities and ligament diameters. We investigate the effect of pre-existing lattice defects on nu(p) of np-Au using molecular dynamics simulations. Uniaxial compression of np-Au samples that have the same porous morphology, but distinct defect densities, shows that a high density of pre-existing defects reduces nu(p). We interpret this observation by linking nanoscale tension-compression asymmetry in individual ligaments to the synergistic interplay between defects and surfaces, and ultimately to the plastic transverse coupling in np-Au. (C) 2020 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.

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