Regensburg 2022 – wissenschaftliches Programm
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MM: Fachverband Metall- und Materialphysik
MM 35: Nanomaterials: Structure & Properties
MM 35.8: Vortrag
Donnerstag, 8. September 2022, 17:45–18:00, H46
Fabrication and compressive behavior of monolithic nanoporous niobium at macroscale — •Seoyun Sohn1,2, Shan Shi2,1, Jürgen Markmann1,2, and Jörg Weissmüller2,1 — 1Institute of Materials Mechanics, Helmholtz-Zentrum hereon, Geesthacht, Germany — 2Institute of Materials Physics and Technology, Hamburg University of Technology, Hamburg, Germany
Studying the mechanical performance of nanoporous (np) metals allows us to understand nanoscale solids as well as to design functional applications. However, the majority of studies have been confined to face-centered cubic noble metals such as gold and palladium due to high electronegativity which facilitates preparation by dealloying. Since the electrochemical or chemical dealloying involves a selective dissolution of less noble constituent(s) in an electrolyte solution, the remaining constituent should be nobler to form a bicontinuous porous structure. Niobium (Nb) on the other hand is less noble than gold, has higher stiffness and lower ductility, and its crystal lattice is body-centered cubic. In this work, np Nb was fabricated out of Ni75Nb25 by liquid metal dealloying; the ligament size could be controlled from 400 nm to more than 1 um by adjusting dealloying time and temperature. Each sample body is a few mm in size and freestanding, which allows us to perform conventional macro-compression tests to measure the strength and stiffness of the nano-ligament scaffold. Our observations support that the material strength is enhanced with smaller ligaments. More interestingly, our np Nb shows extremely anomalous compliance.