(Invited) Tailor-Made Hierarchical Nested-Network Nanoporous Metals By Dealloying

Abstract

Structural hierarchy is known to optimize functional and mechanical behaviors in deliberately designed structures and natural materials. The benefits of hierarchy implementing the high strength and the high surface-to-volume of nanoscale objects into hierarchical structures would lead to even more interesting mechanical characteristics and more opportunities for interface- or surface-controlled functional applications. This talk focuses on nested network random nanomaterials "hierarchical nanoporous gold" made by two-stage self-organization dealloying processes, which processes allow for large samples contained over trillions of struts to be synthesized. Both the strut size and porosity at each hierarchy level are tuned independently. The strut size can be controlled from 10 nm to 300 nm, and the porosity from 80% to 90%. Compression tests on these hierarchical nanoporous gold materials demonstrated that the structural hierarchy brings enhanced mechanics for truly nanoscale network materials. The experiments are well supported by our proposed scaling laws for the stiffness and strength for nested network with different numbers of hierarchy levels [1].[1] S. Shi, Y. Li, B.-N. Ngo-Dinh, J. Markmann and J. Weissmüller, Scaling behavior of stiffness and strength of hierarchical network nanomaterials, Science 371 (6533), 2021.