Please use this identifier to cite or link to this item: https://doi.org/10.15480/882.3666
Publisher DOI: 10.1016/j.actamat.2021.116979
Title: On factors defining the mechanical behavior of nanoporous gold
Language: English
Authors: Zandersons, Birthe 
Lührs, Lukas 
Li, Yong  
Weissmüller, Jörg 
Keywords: Dealloying;Mechanical properties;Nanoporous gold;Scaling laws;Strength;Young's modulus
Issue Date: 18-May-2021
Publisher: Elsevier Science
Source: Acta Materialia 215: 116979 (2021-08-15)
Journal: Acta materialia 
Abstract (english): 
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.
URI: http://hdl.handle.net/11420/9904
DOI: 10.15480/882.3666
ISSN: 1359-6454
Institute: Werkstoffphysik und -technologie M-22 
Document Type: Article
Funded by: Deutsche Forschungsgemeinschaft (DFG) 
Project: SFB 986: Teilprojekt B2 - Feste und leichte Hybridwerkstoffe auf Basis nanoporöser Metalle 
License: CC BY-NC-ND 4.0 (Attribution-NonCommercial-NoDerivatives) CC BY-NC-ND 4.0 (Attribution-NonCommercial-NoDerivatives)
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