Gyroidal structures as approximants to nanoporous metal foams: clues from mechanical properties

The present study focuses on the relationship between structure and mechanical properties in nanoporous (NP) metal foams. Experimental and numerical findings suggest for NP Au and single gyroid structures similar topological features. In particular, NP Au and single gyroids are shown to exhibit almost coincident form factors, defined as a function of specific surface area and ligament thickness. Furthermore, nanoindentation of NP Au and uniaxial compression of polymeric single gyroids with comparable relative density of about 0.3 result in almost overlapping relative Young's moduli. Surface topology and elastic deformation behavior allow considering single gyroids as approximants of the NP Au structure. Consequently, it can be also expected that NP Au and single gyroids undergo similar local deformation mechanisms. These do not involve pure bending of ligaments, but rather a combination of shear and torsion components.