Microstructure-sensitive mechanical properties of nanoporous gold: a molecular dynamics study

Abstract

The present paper aims to investigate the microstructural differences of models used in nanoporous metals and research on the mechanical response of various morphological architectures, including cube, gyroid, diamond and stochastic bicontinuous structures. By using molecular dynamics simulations, the influential parameters of architectural morphology, relative density and ligament diameter on the mechanical properties of nanoporous gold under uniaxial tension are presented and further compared with current constitutive theory and experimental results of the literature. The differences among those structures are critically demonstrated and addressed. Results present that the Young's modulus as a function of relative density and the yield strength as a function of ligament diameter both display power-law relation but the scaling exponents vary with the microstructures. The modulus of stochastic bicontinuous structures is in better agreement with the experimental results. The relationship between yield stress and relative density is approximately linear, indicating the yielding behavior may be dominated by the yielding of ligaments in the process of deformation. These results promise much for the design of nanoporous structures with tunable, desirable mechanical properties stemming from various microstructures.