Athermal mechanisms of size-dependent crystal flow gleaned from three-dimensional discrete dislocation simulations

Rao, Satish I.; Dimiduk, Dennis M.; Parthasarathy, Triplicane A.; Uchic, Michael D.; Tang, Meijie; Woodward, C.

doi:10.1016/j.actamat.2008.03.011

Cited by 292 publications

(191 citation statements)

References 57 publications

(142 reference statements)

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“…As a result, the extended view points to the conclusion that the effect of FIB milling on metallic micropillar compression is negligible provided the pillar has some initial dislocation structure before milling (El-Awady et al, 2009), that provides an initial distribution of dislocation sources. This way the truncation of dislocation sources originates the size effects Rao et al, 2008;Akarapu et al, 2010;Ngan, 2011). Recent studies in mechanically pre-strained Mo pillars, both with (Schneider et al, 2010) and without FIB milling (Shim et al, 2009), support this view, because size effects are independent of whether the initial defect distribution is due to FIB machining or mechanical pre-strain.…”

Section: Effect Of Micropillar Size and Ion Irradiationmentioning

confidence: 56%

Micropillar compression of LiF [111] single crystals: Effect of size, ion irradiation and misorientation

Soler

Molina-Aldareguia

Segurado

et al. 2012

International Journal of Plasticity

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The mechanical response under compression of LiF single crystal micropillars oriented in the [111] direction was studied. Micropillars of different diameter (in the range 1-5 u.m) were obtained by etching the matrix in directionally-solidified NaCl-LiF and KCl-LiF eutectic compounds. Selected micropillars were exposed to high-energy Ga + ions to ascertain the effect of ion irradiation on the mechanical response. Ion irradiation led to an increase of approximately 30% in the yield strength and the maximum compressive strength but no effect of the micropillar diameter on flow stress was found in either the as-grown or the ion irradiated pillars. The dominant deformation micromechanisms were analyzed by means of crystal plasticity finite element simulations of the compression test, which explained the strong effect of micropillar misorientation on the mechanical response. Finally, the lack of size effect on the flow stress was discussed to the light of previous studies in LiF and other materials which show high lattice resistance to dislocation motion.

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Section: Effect Of Micropillar Size and Ion Irradiationmentioning

confidence: 56%

Micropillar compression of LiF [111] single crystals: Effect of size, ion irradiation and misorientation

Soler

Molina-Aldareguia

Segurado

et al. 2012

International Journal of Plasticity

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“…Figure 4(f) shows two dark field images of a compressed pillar, and, remarkably, demonstrates that all remaining dislocations lie in f111g planes, which experience no resolved force during deformation, suggesting dislocation starvation as a dominant deformation mechanism [25]. Several atomistic and statistical simulations have corroborated this phenomenon in their explanations of size-dependent strengthening [36,[43][44][45][46][47].…”

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confidence: 69%

Microstructure versus Size: Mechanical Properties of Electroplated Single Crystalline Cu Nanopillars

2010

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We report results of uniaxial compression experiments on single-crystalline Cu nanopillars with nonzero initial dislocation densities produced without focused ion beam (FIB). Remarkably, we find the same power-law size-driven strengthening as FIB-fabricated face-centered cubic micropillars. TEM analysis reveals that initial dislocation density in our FIB-less pillars and those produced by FIB are on the order of 10 14 m À2 suggesting that mechanical response of nanoscale crystals is a stronger function of initial microstructure than of size regardless of fabrication method.

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“…Up to now, different modelling approaches have been proposed to characterise phenomena observed in compression of nano-and micron-sized pillars, such as a source-truncation model [19], a source-exhaustion hardening model [20], multiplication via a single-arm source operation [19,21], a weakest-link theory [22] and a dislocation-starvation/dislocation-nucleation theory [23]. The general premise of these theories is to represent dislocation-source operations in a discrete fashion, where strength of samples is linked to the source lengths.…”

Section: Introductionmentioning

confidence: 99%

Indentation studies in b.c.c. crystals with enhanced model of strain-gradient crystal plasticity

Demiral

Roy

2013

Computational Materials Science

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• This is the author's version of a work that was accepted for publication in the Computational Materials Science. Changes resulting from the publishing process, such as peer review, editing, corrections, structural formatting, and other quality control mechanisms may not be reflected in this document. Changes may have been made to this work since it was submitted for publication. A definitive version was subsequently published at:http://www.sciencedirect.com/science/article/pii/S0927025613004072

show abstract

Athermal mechanisms of size-dependent crystal flow gleaned from three-dimensional discrete dislocation simulations

Cited by 292 publications

References 57 publications

Micropillar compression of LiF [111] single crystals: Effect of size, ion irradiation and misorientation

Micropillar compression of LiF [111] single crystals: Effect of size, ion irradiation and misorientation

Microstructure versus Size: Mechanical Properties of Electroplated Single Crystalline Cu Nanopillars

Indentation studies in b.c.c. crystals with enhanced model of strain-gradient crystal plasticity

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