Indentation response of nanoporous gold from atomistic simulations

Farkas, Diana; Stuckner, Joshua; Umbel, Rachel; Kuhr, Bryan; Demkowicz, Michael J.

doi:10.1557/jmr.2018.72

Cited by 13 publications

(4 citation statements)

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“…A dislocation accumulation scenario has already been observed in nanoporous gold, both in experiments 46,47 and in MD studies. 10,48 In order to characterize the plastic activity under nanoindentation, Fig. 6 displays the atomic shear strain that resulted in the original and in the irradiated foam after full indentation to 6 nm on P1.…”

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confidence: 99%

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Nanoindentation tests of heavy-ion-irradiated Au foams—molecular dynamics simulation

Ruestes

Anders

Bringa

et al. 2018

Journal of Applied Physics

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Irradiation by light ions may change the mechanical properties of nanofoams. Using moleculardynamics simulation, we study the effect of irradiating a Au foam (porosity, 50%, and ligament diameter, 3 nm) with heavy ions: here, 10 keV Au ions up to a dose of 4 Â 10 16 m À2 . We demonstrate that in consequence, the ligament morphology changes in the irradiated region, caused by local melting. The changes in mechanical properties are monitored by simulated nanoindentation tests. We find that the foam hardness is only around 1/3 of the hardness of a bulk Au crystal. Irradiation increases the hardness of the foam by around 10% in the central irradiated area. The plastic zone extends to only 1.5 a c , where a c denotes the contact radius; this value is unchanged under irradiation. The hardness increase after irradiation is attributed to two concurring effects. To begin with, irradiation induces melting and annealing of the ligaments, leading to their coarsening and alleviating surface stress, which in turn increases the dislocation nucleation threshold. In addition, irradiation introduces a stacking fault forest that acts as an obstacle to dislocation motion.

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confidence: 99%

“…The plastic zone in both cases is small, as ligaments constrain dislocation motion locally, in line with recent studies. 48,49…”

Section: à ámentioning

confidence: 99%

Nanoindentation tests of heavy-ion-irradiated Au foams—molecular dynamics simulation

Ruestes

Anders

Bringa

et al. 2018

Journal of Applied Physics

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“…One route uses random structures (spinodal decomposition, leveled waves); the second is based on unit cells (Gibson–Ashby, gyroid, diamond). The mechanical behavior of random structures is usually predicted with molecular dynamics (MD) simulations [ 12 , 13 , 14 ] or with continuum mechanics using FE-solid or voxel models [ 8 , 15 , 16 ]. In combination with plasticity, also the FE-models lead to large computing times and allow only for a very limited number of simulations.…”

Section: Introductionmentioning

confidence: 99%

“…Furthermore, the limited model size makes it extremely difficult to simulate a nanoindentation test that averages over sufficient features, such that it can be analyzed like an experiment. One of the rare examples that goes in this direction is the work of Farkas et al [ 14 ], which presents a MD simulation of nanoindentation in a single crystal with a relative density of 0.67 and ligament diameter of 2 nm.…”

Section: Introductionmentioning

confidence: 99%

A Strategy for Dimensionality Reduction and Data Analysis Applied to Microstructure–Property Relationships of Nanoporous Metals

Huber

2021

Materials

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Nanoporous metals, with their complex microstructure, represent an ideal candidate for the development of methods that combine physics, data, and machine learning. The preparation of nanporous metals via dealloying allows for tuning of the microstructure and macroscopic mechanical properties within a large design space, dependent on the chosen dealloying conditions. Specifically, it is possible to define the solid fraction, ligament size, and connectivity density within a large range. These microstructural parameters have a large impact on the macroscopic mechanical behavior. This makes this class of materials an ideal science case for the development of strategies for dimensionality reduction, supporting the analysis and visualization of the underlying structure–property relationships. Efficient finite element beam modeling techniques were used to generate ~200 data sets for macroscopic compression and nanoindentation of open pore nanofoams. A strategy consisting of dimensional analysis, principal component analysis, and machine learning allowed for data mining of the microstructure–property relationships. It turned out that the scaling law of the work hardening rate has the same exponent as the Young’s modulus. Simple linear relationships are derived for the normalized work hardening rate and hardness. The hardness to yield stress ratio is not limited to 1, as commonly assumed for foams, but spreads over a large range of values from 0.5 to 3.

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Mechanical properties of nanoporous gold subjected to tensile stresses in real-time, sub-microscopic scale

Stuckner

Murayama

2019

J Mater Sci

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Indentation response of nanoporous gold from atomistic simulations

Abstract: Abstract

Cited by 13 publications

References 62 publications

Nanoindentation tests of heavy-ion-irradiated Au foams—molecular dynamics simulation

Nanoindentation tests of heavy-ion-irradiated Au foams—molecular dynamics simulation

A Strategy for Dimensionality Reduction and Data Analysis Applied to Microstructure–Property Relationships of Nanoporous Metals

Mechanical properties of nanoporous gold subjected to tensile stresses in real-time, sub-microscopic scale

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