Effects of structural hierarchy and size on mechanical behavior of nanoporous gold

Publikationstyp
Journal Article
Date Issued
2024-07-01
Sprache
English
Author(s)
Jeon, Hansol
Markmann, Jürgen 
Werkstoffphysik und -technologie M-22  
Shi, Shan  
Integrated metallic Nanomaterialssystems M-EXK4  
TORE-DOI
10.15480/882.9614
TORE-URI
https://hdl.handle.net/11420/47649
Journal
Acta materialia  
Volume
273
Article Number
119954
Citation
Acta Materialia 273: 119954 (2024)
Publisher DOI
10.1016/j.actamat.2024.119954
Scopus ID
2-s2.0-85191790410
Publisher
Elsevier Science
Nanoporous gold with a hierarchical structure has prospects as an advanced functional material with enhanced mechanical properties, but how the hierarchical structure affects its mechanical properties compared to a unimodal structure has not been revealed. Here, we investigate the mechanical behavior of hierarchically-structured nanoporous gold and unimodally-structured nanoporous gold with the same relative density by micropillar compressive tests in dry and electrolyte environment. The ligament size at the upper-level structure in hierarchically-structured nanoporous gold and the ligament size in unimodally-structured nanoporous gold are kept similar, while having hierarchically-structured samples with ligament sizes of 10 to 50 nm at lower-level structure. We find that hierarchically-structured nanoporous gold shows greater compressive strength and pronounced stress-variation by oxidization of the surface compared to unimodally-structured nanoporous gold. A ligament-size dependency on the lower-level structure in hierarchical samples is observed, with compressive strength and stress variation by surface oxidation increasing as the lower-level ligament size decreases. Three-dimensionally reconstructed structure analysis suggests that the enhanced mechanical properties of hierarchically-structured nanoporous gold are attributed to the better-connected network of ligaments originating from two separated dealloying-coarsening procedures. The influence of dislocation activities depending on characteristic sizes is also discussed to elucidate the distinguished mechanical behavior.
Subjects
Compressive test
Electrochemically tunable strength
Hierarchical structure
Microcompression
Nanoporous gold
Size effect
DDC Class
620.1: Engineering Mechanics and Materials Science
Publication version
publishedVersion
Lizenz
https://creativecommons.org/licenses/by/4.0/
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