Continuum modeling of dislocation starvation and subsequent nucleation in nano-pillar compressions

Jérusalem, Antoine; Fernández, Ana; Kunz, Allison; Greer, Julia R.

doi:10.1016/j.scriptamat.2011.10.009

Cited by 26 publications

(8 citation statements)

References 25 publications

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“…This microstructure results in a dramatically different stress-strain response as compared to the system with curved dislocations: because we have neither an increase in density nor a line tension one can only observe a linear hardening (regime II) which -regardless the boundary condition -is followed by a nearly elastic regime III where the stresses are considerably different from those reached for the system with dislocation loops. The loss of dislocations through surfaces (and ultimately the 'dislocation starvation') has been experimentally observed in nano/micro pillar compression tests (Shan et al, 2008;Jerusalem et al, 2012) as well. This starvation effect also gave rise to a second elastic regime as observed in our edge dislocation system.…”

Section: Study 1: the Influence Of Boundary Conditions (Case 1)mentioning

confidence: 94%

A link between microstructure evolution and macroscopic response in elasto-plasticity: Formulation and numerical approximation of the higher-dimensional continuum dislocation dynamics theory

Sandfeld

Thawinan

Wieners

2015

International Journal of Plasticity

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Micro-plasticity theories and models are suitable to explain and predict mechanical response of devices on length scales where the influence of the carrier of plastic deformation -the dislocations -cannot be neglected or completely averaged out. To consider these effects without resolving each single dislocation a large variety of continuum descriptions has been developed, amongst which the higher-dimensional continuum dislocation dynamics (hdCDD) theory by Hochrainer et al. (Phil. Mag. 87, pp. 1261-1282) takes a different, statistical approach and contains information that are usually only contained in discrete dislocation models. We present a concise formulation of hdCDD in a general single-crystal plasticity context together with a discontinuous Galerkin scheme for the numerical implementation which we evaluate by numerical examples: a thin film under tensile and shear loads. We study the influence of different realistic boundary conditions and demonstrate that dislocation fluxes and their lines' curvature are key features in small-scale plasticity.

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Section: Study 1: the Influence Of Boundary Conditions (Case 1)mentioning

confidence: 94%

A link between microstructure evolution and macroscopic response in elasto-plasticity: Formulation and numerical approximation of the higher-dimensional continuum dislocation dynamics theory

Sandfeld

Thawinan

Wieners

2015

International Journal of Plasticity

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“…В англоязычной литературе такой режим получил образное название " дислокационный голод" (dislocation starvation) [89,103,104,307]. Подобный режим наблюдался во многих ГЦК и ОЦК материалах при D < 1 µm [308][309][310]. В результате на столбиках из отожженного монокристаллического Mo диаметром ∼ 100 nm с полусферической вершиной, вырезанных из массива c помощью FIB и продеформированных в таком режиме in situ в колонне ТЕМ, достигался предел текучести, близкий или равный теоретическому пределу прочности τ th [309].…”

Section: размерные эффекты природа деформации и разрушения в наношкалеunclassified

Наноиндентирование И Механические Свойства Материалов В Субмикро- И Наношкале. Недавние Результаты И Достижения (О Б З О Р)

Головин¹

2021

Физика Твердого Тела

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The review discusses the details of various materials mechanical behavior in submicro- and nanoscale. Significant advances in this scope result from the development of wide family of load based precise nanotesting techniques called nanoindentation. But nowadays, nanomechanical properties are studied not only by nanoindentation techniques in narrow sense, i.e. local loading of macro, micro and nanoscale objects. Nanomechanical load testing is discussed here within a wider scope employing precise deformation measurement with nanometer scale resolution caused by various types of low load application to the object under study including uniaxial compression or extension, shearing, bending or twisting, optionally accompanied by in situ monitoring sample microstructure using scanning and transmission electron microscopy and Laue microdiffraction technique. The main courses of experimental techniques development in recent ten years along with the results obtained using them in single, poly and nano crystalline materials, composites, films and coatings, amorphous solids and such biomaterials as tissues, living cells and macromolecules are described. Special attention is paid to deformation size effects and atomic mechanisms in nanoscale. This review is a natural continuation and development of the review published at Fiz.Tverd.Tela vol.50, issue 12, 2008 of the same author that discusses details of nanomechanical properties of solids. Current review includes wider range of nanomechanical testing concepts and recent achievements in the scope. The work was supported by RFBR grant for project #19-12-50235.

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“…Some attempts have been made to directly correlate appropriate constitutive models to finite element (FE) analysis that can handle complex geometry easily, apply boundary conditions accurately and compute efficiently. In most cases, FE simulations using the phenomenological (Jérusalem et al, 2012;Maaß et al, 2009;Raabe et al, 2007;Zhang and Shang, 2014) and dislocation-based crystal plasticity theories (Hurtado and Ortiz, 2012;Kuroda, 2013) are employed to study micropillar plasticity because they can analyze microscopic heterogeneity associated with plastic deformation in materials and address the issue of high strain rate in dislocation dynamics simulations.…”

Section: Introductionmentioning

confidence: 99%

“…Some FE analyses using crystal plasticity models have already been employed to study size-dependent flow strength (Hurtado and Ortiz, 2012), microplastic deformation mode (Kuroda, 2013) and smoother transition to plasticity observed in micro-compression tests (Jérusalem et al, 2012). A general introduction of strain bursts into the crystal plasticity finite element framework that is capable of capturing the strain bursts in the macroscopic stressstrain behavior of single crystalline micropillar compressions, has been described in Zhang and Shang (2014).…”

Section: Introductionmentioning

confidence: 99%

A stochastic model for the temporal aspects of flow intermittency in micropillar compression

Zhang

Shang

et al. 2014

International Journal of Solids and Structures

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a b s t r a c tSystematic experimental investigations have demonstrated that the plastic deformation of micropillar proceeds through a sequence of intermittent bursts, the sizes of which follow power-law statistics. In this study, a stochastic model based on the power-law distribution of burst size is formulated in the framework of crystal plasticity in order to investigate the temporal aspects of flow intermittency in micropillar compression. A Monte Carlo simulation scheme is developed to determine the burst size when a burst activity is captured. This burst size is considered as the displacement boundary condition of burst deformation. Three-dimensional finite element analysis of the model is performed and its predictions are validated by comparison with results from both micro-compression experiments and simulation tests of bulk crystals using the classic crystal plasticity finite element method (CPFEM). The model provides a reasonable prediction of stress-strain responses both at the macroscopic and microscopic scales. Finally, the capability of this model is shown with applications to the intermittent plastic deformation in micropillar compressions, in particular for their burst time durations and burst velocities. The results from such stochastic finite element analysis are shown to be consistent with earlier experimental findings and results of mean-field theory.

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Continuum modeling of dislocation starvation and subsequent nucleation in nano-pillar compressions

Cited by 26 publications

References 25 publications

A link between microstructure evolution and macroscopic response in elasto-plasticity: Formulation and numerical approximation of the higher-dimensional continuum dislocation dynamics theory

A link between microstructure evolution and macroscopic response in elasto-plasticity: Formulation and numerical approximation of the higher-dimensional continuum dislocation dynamics theory

Наноиндентирование И Механические Свойства Материалов В Субмикро- И Наношкале. Недавние Результаты И Достижения (О Б З О Р)

A stochastic model for the temporal aspects of flow intermittency in micropillar compression

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