Nanoporous gold: 3D structural analyses of representative volumes and their implications on scaling relations of mechanical behaviour

Hu, Kaixiong; Ziehmer, Markus; Wang, Ke; Lilleodden, Erica T.

doi:10.1080/14786435.2016.1222087

Cited by 88 publications

(145 citation statements)

References 38 publications

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“…However, there is no differentiation between interconnected branches (branch connects two junctions), and dangling branches (branch connects junction with end). Looking at the dangling branches in Figure 1a, many seem to represent pinched-off ligaments formed during the annealing process, as discussed by Hu et al [7,15]. Furthermore, some very short dangling branches (junctions and ends almost overlap) are present, which do not represent significant features of the structure.…”

Section: Skeleton Branch Type Occurences and Length Distributionsmentioning

confidence: 79%

“…The mean freedangling branch length is calculated as 329 nm, which is again slightly smaller than the mean ligament diameter of 400 nm of the structure. The mean length of the boundary-dangling branches is [7,15]; skeleton-voxels are shown in black in original size; blue spheres mark the junction-voxels, red spheres mark the free end-voxels, and green spheres the end-voxels at the boundary; (b) Schematic 2D drawing of an RVE: The green circles illustrate the ligament ends that are due to the cuts at the RVE boundary. The gray shaped area represents the boundary region where these cut boundary ligaments were found.…”

Section: Skeleton Branch Type Occurences and Length Distributionsmentioning

confidence: 99%

“…A local thickening of a ligament typically leads to an extra junction with a very short dangling branch, which is fully enclosed by the solid ligament. The longer free-dangling branches are assumed to be actual pinched-off ligaments formed during the annealing process of the sample [7,15]. For a skeleton pruning, a criterion for differentiation between unwanted (structurally not meaningful) and pinched-off ligaments would be needed.…”

Section: Skeleton Branch Type Occurences and Length Distributionsmentioning

confidence: 99%

“…This helps with getting a sense of the skeleton and diameter data of the complex NPG structure generated by FIJI. The distribution of the diameter data as analyzed in detail by Hu et al [7,15], gives a first impression about the overall structural characteristics. However, to create a realistic FEM beam model based on the skeleton and diameter information, the non-local information-i.e., the diameter evolution along the ligament-is also important.…”

Section: Introductionmentioning

confidence: 99%

“…Besides very fundamental calculations such as density functional theory (DFT) [13] and molecular dynamics simulations (MD) [11,12,14], there are several simplified finite element method (FEM) models [6,[13][14][15][16][17][18] and even analytical models [19][20][21][22][23][24] for predicting mechanical properties. In many modeling approaches the complex NPG Before the skeleton data were translated into the skeleton FEM beam model, the geometrical data were thoroughly analyzed.…”

Section: Introductionmentioning

confidence: 99%

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Skeletonization, Geometrical Analysis, and Finite Element Modeling of Nanoporous Gold Based on 3D Tomography Data

Richert

Huber

2018

Metals

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Abstract:Various modeling approaches simplify and parametrize the complex network structure of nanoporous gold (NPG) for studying the structure-property relationship based on artificially generated structures. This paper presents a computational efficient and versatile finite element method (FEM) beam model that is based on skeletonization and diameter information derived from the original 3D focused ion beam-scanning electron microscope (FIB-SEM) tomography data of NPG. The geometrical skeleton network is thoroughly examined for a better understanding of the NPG structure. A skeleton FEM beam model is derived that can predict the macroscopic mechanical behavior of the material. Comparisons between the mechanical response of this skeleton beam model and a solid FEM model are conducted. Results showed that the biggest-sphere diameter algorithm implemented in the open-source software FIJI, commonly used for geometrical analysis of microstructural data, overestimates the diameter of the curved NPG ligaments. The larger diameters lead to a significant overestimation of macroscopic stiffness and strength by the skeleton FEM beam model. For a parabolic shaped ligament with only 20% variation in its diameter, a factor of more than two was found in stiffness. It is concluded that improved algorithms for image processing are needed that provide accurate diameter information along the ligament axis.

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Section: Skeleton Branch Type Occurences and Length Distributionsmentioning

confidence: 79%

Section: Skeleton Branch Type Occurences and Length Distributionsmentioning

confidence: 99%

Section: Skeleton Branch Type Occurences and Length Distributionsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Skeletonization, Geometrical Analysis, and Finite Element Modeling of Nanoporous Gold Based on 3D Tomography Data

Richert

Huber

2018

Metals

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Mechanical Properties of FeCr‐Based Composite Materials Elaborated by Liquid Metal Dealloying towards Bioapplication

et al. 2020

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Liquid metal dealloying (LMD) is a new technology to create porous materials. From a (FeCr) x-Ni 1-x precursor, it is possible to get a bicontinuous structure of FeCr and Mg: a metal-metal composite. An etching step removes the Mg solidstate solution phase to give a metal-air composite. The last step, polymer infiltration, gives metal-polymer composites. Herein, metal-metal, metal-air, and metal-polymer (rubbery or glassy polymers) with three different phase ratios are elaborated by LMD from Ni-based precursors and their mechanical properties are analyzed. A full polymer infiltration into the pores is obtained and the epoxy polymer properties are not affected by the metallic foam presence. Concerning control of the mechanical properties, the material's second-phase selection is a key factor. Herein, it is shown that the mechanical properties are easily designed by optimizing phase ratio, ligament size, and second-phase type and that these materials are promising materials for biomedical applications.

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Robust Metallic Actuators Based on Nanoporous Gold Rapidly Dealloyed from Gold–Nickel Precursors

Cheng

Lührs

2021

Adv Funct Materials

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Dealloyed nanoporous gold (np‐Au) has applications as oxygen reduction catalysis in Li‐air batteries and fuel cells, or as actuators to convert electricity into mechanical energy. However, it faces the challenges of coarsening‐induced structure instability, mechanical weakness due to low relative densities, and slow dealloying rates. Here, monolithic np‐Au is dealloyed from a single‐phase Au25Ni75 solid‐solution at a one‐order faster dealloying rate, ultra‐low residual Ni content, and importantly, one‐third more relative density than np‐Au dealloyed from conventional Au25Ag75. The small atomic radius and low dealloying potential of the sacrificing element Ni are intrinsically beneficial to fast produce high relative density np‐Au, as predicted by a general model for dealloying of binary alloys and validated by experiments. Stable, durable, and reversible actuation of np‐Au takes place under cyclic potential triggering in alkaline and acidic electrolytes with negligible coarsening‐induced strain‐shift. The thermal and mechanical robustness of bulk np‐Au is confirmed by two‐order slower ligament coarsening rates during annealing at 300 °C and 45 MPa macroscopic yielding strength distinctive from the typical early onset of plastic yielding. This article opens a rich direction to achieve high relative density np‐Au which is essential for porous network connectivity, mechanical strength, and nanostructure robustness for electrochemical functionality.

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Nanoporous gold: 3D structural analyses of representative volumes and their implications on scaling relations of mechanical behaviour

Cited by 88 publications

References 38 publications

Skeletonization, Geometrical Analysis, and Finite Element Modeling of Nanoporous Gold Based on 3D Tomography Data

Skeletonization, Geometrical Analysis, and Finite Element Modeling of Nanoporous Gold Based on 3D Tomography Data

Mechanical Properties of FeCr‐Based Composite Materials Elaborated by Liquid Metal Dealloying towards Bioapplication

Robust Metallic Actuators Based on Nanoporous Gold Rapidly Dealloyed from Gold–Nickel Precursors

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