Options
On factors defining the mechanical behavior of nanoporous gold
Citation Link: https://doi.org/10.15480/882.3666
Publikationstyp
Journal Article
Date Issued
2021-05-18
Sprache
English
TORE-DOI
TORE-URI
Journal
Volume
215
Article Number
116979
Citation
Acta Materialia 215: 116979 (2021-08-15)
Publisher DOI
Scopus ID
Publisher
Elsevier Science
Nanoporous gold (NPG) made by dealloying takes the form of a network of nanoscale struts or “ligaments”. It is well established that the material's mechanical behavior is strongly affected by its ligament size, L and by its solid volume fraction, φ. We explore the mechanical behavior of NPG, with an emphasis on establishing a consistent data set with comparable L but covering a significant range of initial φ. Specimens are prepared from Ag-Au master alloys with their Au atom fraction, xAu0 in the range 0.20–0.35. Since dealloying replaces Ag with voids, φ may be expected to agree with xAu0. Yet, spontaneous plastic deformation events during dealloying can result in macroscopic shrinkage, decoupling φ from xAu0. This raises the question, how do φ and xAu0 separately affect the mechanical behavior? We confirm two recent suggestions, namely i) a modified Roberts-Garboczi-type scaling law for Young's modulus versus φ of the material in its as-prepared state and ii) the relevance of an apparent “load-bearing solid fraction” for Young's modulus as well as strength. Yet, remarkably, we find that stiffness and strength of the as-prepared material show a much better correlation to xAu0 as compared to φ. This can be understood as a consequence of the microstructural changes induced by shrinkage. Studying the microstructure evolution during annealing, we also confirm the suggestion that coarsening entails an enhanced loss in stiffness for samples with lesser solid fraction. This finding confirms concerns about the notion of self-similar coarsening as a general behavior of dealloying-made network materials.
Subjects
Dealloying
Mechanical properties
Nanoporous gold
Scaling laws
Strength
Young's modulus
DDC Class
600: Technik
Funding Organisations
Publication version
publishedVersion
Loading...
Name
1-s2.0-S1359645421003591-main.pdf
Size
2.71 MB
Format
Adobe PDF