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

• DOI: 10.1016/j.scriptamat.2020.03.046
• Publication Date: 2020-05-21T22:51:38Z
• Authors: Luoxia Cao; Zhi Zeng; Feifei Fan
• Keywords: Nanoporous; Poisson's ratio; Lattice (music)

Abstract Nanoporous gold (np-Au) exhibits variations in the value of the plastic Poisson's ratio, νp – ranging from negative to positive – often for similar relative densities and ligament diameters. We investigate the effect of pre-existing lattice defects on νp 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 νp. 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.