One-to-one spatially matched experiment and atomistic simulations of nanometre-scale indentation

Oliver, David J.; Paul, William; Ouali, Mehdi El; Hagedorn, Till; Miyahara, Yoichi; Qi, Yue; Grütter, Peter

doi:10.1088/0957-4484/25/2/025701

Cited by 21 publications

(18 citation statements)

References 39 publications

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“…MD simulations also suggested that material transfer usually occurs during contact separation [30]. A similar phenomenon was found by Oliver et al [100] when they performed one-to-one spatially matched experiment and atomistic simulations of nanometre-scale indentation; they reported that many features of the experiment were correctly reproduced by MD simulations, in some cases only when an atomically rough indenter rather than a smooth repulsive-potential indenter is used, tip wetting being one of these features. Paul et al [101] highlighted the need to further explore the role of adhesive forces and tip wetting, ranging from the mechanisms of substrate-to-tip material transfer to electronic transport properties.…”

Section: Role Of Adhesive Forces and Tip Wettingsupporting

confidence: 71%

Atomistic Studies of Nanoindentation—A Review of Recent Advances

2017

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This review covers areas where our understanding of the mechanisms underlying nanoindentation has been increased by atomistic studies of the nanoindentation process. While such studies have been performed now for more than 20 years, recent investigations have demonstrated that the peculiar features of nanoplasticity generated during indentation can be analyzed in considerable detail by this technique. Topics covered include: nucleation of dislocations in ideal crystals, effect of surface orientation, effect of crystallography (fcc, bcc, hcp), effect of surface and bulk damage on plasticity, nanocrystalline samples, and multiple (sequential) indentation. In addition we discuss related features, such as the influence of tip geometry on the indentation and the role of adhesive forces, and how pre-existing plasticity affects nanoindentation.

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Section: Role Of Adhesive Forces and Tip Wettingsupporting

confidence: 71%

Atomistic Studies of Nanoindentation—A Review of Recent Advances

2017

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“…We reach this conclusion from the experimental evidence of wire-drawing and the variable onset of repulsive contact loading with respect to the tunneling point. Results of molecular dynamics simulations for the same materials system also support the idea that gold is transferred to the tungsten tip during the indentation process [22].…”

Section: Saturation Behaviormentioning

confidence: 52%

Transient adhesion and conductance phenomena in initial nanoscale mechanical contacts between dissimilar metals

Paul¹,

Oliver²,

Miyahara³

et al. 2013

Nanotechnology

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We report on transient adhesion and conductance phenomena associated with tip wetting in mechanical contacts produced by the indentation of a clean W(111) tip into a Au(111) surface. A combination of atomic force microscopy and scanning tunneling microscopy was used to carry out indentation and to image residual impressions in ultra-high vacuum. The ∼7 nm radii tips used in these experiments were prepared and characterized by field ion microscopy in the same instrument. The very first indentations of the tungsten tips show larger conductance and pull-off adhesive forces than subsequent indentations. After ∼30 indentations to a depth of ∼1.7 nm, the maximum conductance and adhesion forces reach steady state values approximately 12 × and 6 × smaller than their initial value. Indentation of W(111) tips into Cu(100) was also performed to investigate the universality of tip wetting phenomena with a different substrate. We propose a model from contact mechanics considerations which quantitatively reproduces the observed decay rate of the conductance and adhesion drops with a 1/e decay constant of 9-14 indentation cycles. The results show that the surface composition of an indenting tip plays an important role in defining the mechanical and electrical properties of indentation contacts.

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“…For example, different tip−substrate adsorption behavior could be seen under UHV conditions, if not enough hydrogen is available to saturate the tip or if additional species preferentially react with the hydrogen and effectively remove it from the tip, or with different materials (as with the tungsten indenter on gold 12 ).…”

Section: Discussionmentioning

confidence: 99%

Molecular Dynamics Investigation of the Effects of Tip–Substrate Interactions during Nanoindentation

et al. 2015

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Nanoindentation in molecular dynamics (MD) simulations typically uses highly idealized indenter tip models. Such tips usually consist of either a single sphere or a collection of atoms, both of which are purely repulsive in their interactions with the substrate. It is also assumed that there is no environmental or substrate contamination, nor is there a surface oxide layer. In this work we examine the effects of these assumptions by comparing detailed MD simulations utilizing varying interaction potentials against both experimental atomic force microscopy observations and calculations using density functional theory. Specifically, we examine the effect of a tip−substrate interaction on the indenter under clean, hydrogenated, and oxidized conditions. We find that under clean or oxidized conditions (where we include oxygen on the nickel surface to mimic a passivating NiO layer) there is a substantial material transfer from the substrate to the tip. This material (Ni atoms) remains adsorbed on the tip upon retraction. However, the presence of hydrogen on the diamond tip drastically reduces, or even altogether eliminates, this material transfer, therefore having an effect much larger than that of a contaminating oxide layer.

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One-to-one spatially matched experiment and atomistic simulations of nanometre-scale indentation

Cited by 21 publications

References 39 publications

Atomistic Studies of Nanoindentation—A Review of Recent Advances

Atomistic Studies of Nanoindentation—A Review of Recent Advances

Transient adhesion and conductance phenomena in initial nanoscale mechanical contacts between dissimilar metals

Molecular Dynamics Investigation of the Effects of Tip–Substrate Interactions during Nanoindentation

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