Direct observation of liquid-like behavior of a single Au grain boundary

Casillas, Gilberto; Ponce, Arturo; Velázquez‐Salazar, J. Jesús; José–Yacamán, Miguel

doi:10.1039/c3nr01501g

Cited by 12 publications

(11 citation statements)

References 27 publications

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“…1,2 Despite the fact that Ag nanowires (NWs) have been synthesized by different techniques, 3,4 the structural and mechanical aspects of freestanding NWs, which are of vital importance in optimizing the performance of nano-architectures, remain poorly understood. [5][6][7][8] The mechanical properties of a bulk specimen are typically studied by employing the uniaxial tensile loading test. As sample dimensions downscale to the nanometer range, experiments on the deformation of materials under tension become more challenging due to the difficulties in object handling.…”

mentioning

confidence: 99%

Void-assisted plasticity in Ag nanowires with a single twin structure

Wang

Huang

et al. 2014

Nanoscale

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confidence: 99%

Void-assisted plasticity in Ag nanowires with a single twin structure

Wang

Huang

et al. 2014

Nanoscale

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“…Previous experimental results had suggested the formation of a liquid-like Au neck in nanometer-scale single-asperity contacts on gold surfaces by diffusion of Au atoms along surface and contact [ 15 – 19 ]. We assumed that the neck formation by diffusion would manifest itself as contact ageing in slide–hold–slide experiments on the time scale of seconds, similar to the development of grain boundaries in the fusion of gold nanoparticles [ 16 ]. In our experiments, the holding time before sliding was varied between 252 μs ( v = 3.1 μm·s −1 ) and 100 s. As our system was drifting by only one atomic distance per 10 s, we should be able to detect effects of the holding times up to 10 s. No static friction peak was observed for any of the holding times for SiO x /Si tips sliding against Au(111).…”

Section: Discussionmentioning

confidence: 99%

Friction force microscopy of tribochemistry and interfacial ageing for the SiO_x/Si/Au system

Petzold¹,

Koch²,

Bennewitz³

2018

Beilstein J. Nanotechnol.

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Friction force microscopy was performed with oxidized or gold-coated silicon tips sliding on Au(111) or oxidized Si(100) surfaces in ultrahigh vacuum. We measured very low friction forces compared to adhesion forces and found a modulation of lateral forces reflecting the atomic structure of the surfaces. Holding the force-microscopy tip stationary for some time did not lead to an increase in static friction, i.e., no contact ageing was observed for these pairs of tip and surface. Passivating layers from tip or surface were removed in order to allow for contact ageing through the development of chemical bonds in the static contact. After removal of the passivating layers, tribochemical reactions resulted in strong friction forces and tip wear. Friction, wear, and the re-passivation by oxides are discussed based on results for the temporal development of friction forces, on images of the scanned area after friction force microscopy experiments, and on electron microscopy of the tips.

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“…This is the case for stress-assisted grain growth 78 and rotation, 13 , 79 for which diffusion coeffi cients seem to be close to those of the liquid phase, even at room or moderate temperatures. 44 Among these mechanisms, shear-migration coupling has recently been the focus of many theoretical and experimental studies. In contrast to dislocation-based plasticity, the shear produced by a moving GB can result in different values, characterized by a coupling factor parameter called β .…”

Section: Grain Boundary Motionmentioning

confidence: 99%

“…Atomic force microscopy holders have also been developed for smaller force ranges. 44 To be indented, a TEM sample must have a specifi c geometry, 45 such as a free half-space ( Figure 2b) in front of the electron-transparent zone. The use of cylindrical nanopillars with a constant section deformed by fl at punch tips is the easiest way to measure stress from load values.…”

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confidence: 99%

In situTEM nanomechanics

Legros²,

Minor³

2015

MRS Bull.

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IntroductionThe mechanical properties of any material are highly correlated with its defect structure. Starting in the late 1950s, 1 in situ straining stages for use in transmission electron microscopes that could provide dynamic observations of dislocation motion in metals were developed. In the following years, research teams fabricated various transmission electron microscopy (TEM) straining holders, including some that could operate at low or high temperature. Since then, in situ TEM straining tests have been performed to study the behavior of dislocations and their interactions with other defects such as twins, grain boundaries (GBs), and interfaces.After early load sensor integration developments, 2 , 3 in situ TEM mechanical testing with quantitative load measurement expanded toward commercialization in the beginning of this century, including mechanical probing modes such as nanoindentation. 4 These developments are particularly useful for studying size effects in materials, whereby mechanical properties and microstructure can be tuned by the physical dimensions (internal such as grain size or external such as fi lm thickness) of materials. 5 -7 At the micrometer or nanometer scale, the sample dimensions can be of the same order as the defects that carry the deformation, such as the length of a dislocation line or the thickness or spacing of twins. When this occurs, strong size effects can change the deformation mechanisms and the corresponding mechanical properties. Quantitative in situ TEM mechanical testing is therefore an ideal tool for studying the origin and principles of these size effects. This review provides an overview of available in situ TEM techniques and recent studies performed on dislocation behavior, dislocation/boundary interactions, deformation twinning, and GB-mediated plasticity. We also provide a critical discussion of the effects of size on different deformation mechanisms and the correlated mechanical properties of materials. Some of these mechanisms are summarized in Figure 1 . In situ TEM straining techniquesVarious tools for mechanical testing by a transmission electron microscope that exist today 8 are briefl y detailed in this section. They span from simple motorized grips to elaborate mechanical testing units capable of returning values for load and displacement.In classical tensile holders for TEM, samples are attached to a pair of jaws, and one side is slowly pulled by an electric motor located in a housing unit outside the TEM instrument. A rigid shaft ensures strain transmission at speeds ranging from 10 nm/s to 10 µm/s. This simple technique 9 has various advantages because of its high versatility. Virtually any thin or thinned sample can be strained as soon as it is attached to In situ transmission electron microscopy (TEM) nanomechanical testing has benefi ted from a number of recent technical developments related to both how deformation is imaged and how deformation is induced and measured inside a TEM instrument. These developments have led to new insights into the ...

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Direct observation of liquid-like behavior of a single Au grain boundary

Cited by 12 publications

References 27 publications

Void-assisted plasticity in Ag nanowires with a single twin structure

Void-assisted plasticity in Ag nanowires with a single twin structure

Friction force microscopy of tribochemistry and interfacial ageing for the SiO_x/Si/Au system

In situTEM nanomechanics

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Direct observation of liquid-like behavior of a single Au grain boundary

Cited by 12 publications

References 27 publications

Void-assisted plasticity in Ag nanowires with a single twin structure

Void-assisted plasticity in Ag nanowires with a single twin structure

Friction force microscopy of tribochemistry and interfacial ageing for the SiOx/Si/Au system

In situTEM nanomechanics

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Friction force microscopy of tribochemistry and interfacial ageing for the SiO_x/Si/Au system