Ligament morphology and elastic modulus of porous structure formed by liquid metal dealloying

We report that the morphology of ligaments also governs the mechanical properties of dealloyed porous materials, in addition to the topology- and size-effects that have been extensively studied previously. Porous Fe–Cr with similar relative density but different Cr content were prepared by liquid metal dealloying. The mechanical efficiency of this material, which is quantified by relative elastic modulus, decreases dramatically with increasing Cr content, although the relative density and network connectivity do not vary significantly. This is linked to the more severe spheroidization of Fe–Cr ligaments at higher Cr, driven by the large excess energy of solid-liquid interfaces and interface energy anisotropy of Fe–Cr under dealloying environment. A shape parameter is introduced to quantitatively account for this ligament-morphology effect. Current study suggests that tailoring interfacial energy, which was largely overlooked in previous studies, is essential to improving the mechanical efficiency of porous or nanoporous materials self-organized in dealloying.