Discrete dislocation modelling of submicron indentation

Widjaja, Andreas; Giessen, van der Erik; Needleman, A.

doi:10.1016/j.msea.2005.01.074

Cited by 42 publications

(42 citation statements)

References 9 publications

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“…However, it should be noted that our results mostly deal with the very first stages of plasticity, where interactions among dislocations are not as relevant. Nevertheless, most of these limitations can also be applied to 2D DD, which has been a very useful tool to study size effects in plasticity [34][35][36][37][38][39], Bearing in mind these limitations for 2D, simulations were carried out to understand the effect of temperature and multiaxiality on the yield stress defined as stress necessary to nucleate stable dislocations from the void surface and on the kinetics of void growth. They were compared with previous results of 3D MD and 2D DD simulations to establish a map of mechanisms and size effects for void growth.…”

Section: Introductionmentioning

confidence: 99%

Molecular dynamics modeling and simulation of void growth in two dimensions

Chang¹,

Segurado²,

Fuente³

et al. 2013

Modelling Simul. Mater. Sci. Eng.

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The mechanisms of growth of a circular void by plastic deformation were studied by means of molecular dynamics in two dimensions (2D). While previous molecular dynamics (MD) simulations in three dimensions (3D) have been limited to small voids (up to s«10nm in radius), this strategy allows us to study the behavior of voids of up to 100 nm in radius. MD simulations showed that plastic deformation was triggered by the nucleation of dislocations at the atomic steps of the void surface in the whole range of void sizes studied. The yield stress, defined as stress necessary to nucleate stable dislocations, decreased with temperature, but the void growth rate was not very sensitive to this parameter. Simulations under uniaxial tension, uniaxial deformation and biaxial deformation showed that the void growth rate increased very rapidly with multiaxiality but it did not depend on the initial void radius. These results were compared with previous 3D MD and 2D dislocation dynamics simulations to establish a map of mechanisms and size effects for plastic void growth in crystalline solids.

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Section: Introductionmentioning

confidence: 99%

Molecular dynamics modeling and simulation of void growth in two dimensions

Chang¹,

Segurado²,

Fuente³

et al. 2013

Modelling Simul. Mater. Sci. Eng.

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“…In these simulations, ''low source density'' materials were considered with the plasticity size effect mainly resulting from sourcelimited plasticity. Widjaja et al (2005Widjaja et al ( , 2006 reported on two-dimensional simulations for the cylindrical indentation of materials with a wide range of source densities. Over the range of indentation depths considered in these studies, the increasing hardness with increasing indentation depth associated with sharp indenters was not obtained and the cylinder radius played a dominant role.…”

Section: Introductionmentioning

confidence: 99%

Discrete dislocation plasticity analysis of the wedge indentation of films

Balint¹,

Deshpande²,

Needleman³

et al. 2006

Journal of the Mechanics and Physics of Solids

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Take-down policy If you believe that this document breaches copyright please contact us providing details, and we will remove access to the work immediately and investigate your claim.Downloaded from the University of Groningen/UMCG research database (Pure): http://www.rug.nl/research/portal. For technical reasons the number of authors shown on this cover page is limited to 10 maximum. AbstractThe plane strain indentation of single crystal films on a rigid substrate by a rigid wedge indenter is analyzed using discrete dislocation plasticity. The crystals have three slip systems at AE35:3 and 90 with respect to the indentation direction. The analyses are carried out for three values of the film thickness, 2, 10 and 50 mm, and with the dislocations all of edge character modeled as line singularities in a linear elastic material. The lattice resistance to dislocation motion, dislocation nucleation, dislocation interaction with obstacles and dislocation annihilation are incorporated through a set of constitutive rules. Over the range of indentation depths considered, the indentation pressure for the 10 and 50 mm thick films decreases with increasing contact size and attains a contact size-independent value for contact lengths A44 mm. On the other hand, for the 2 mm films, the indentation pressure first decreases with increasing contact size and subsequently increases as the plastic zone reaches the rigid substrate. For the 10 and 50 mm thick films sink-in occurs around the indenter, while pile-up occurs in the 2 mm film when the plastic zone reaches the substrate. Comparisons are made with predictions obtained from other formulations: (i) the contact sizeindependent indentation pressure is compared with that given by continuum crystal plasticity; (ii) the scaling of the indentation pressure with indentation depth is compared with the relation proposed by Nix and Gao [1998

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“…This condition is not required in the crystal plasticity calculations because they maintain symmetry about x 1 = 0. The connection between the stress state in the body and the evolution of the dislocation structure is given through a set of constitutive equations, similar to the ones proposed in [26] and used previously in [13] as well as in related investigations, [3,4,27]. These rules control the nucleation, glide, annihilation of dislocations as well as their pinning at obstacles.…”

Section: Discrete Dislocation Plasticitymentioning

confidence: 99%

“…This is precisely the range in which plastic deformation of crystalline solids is known to be size dependent and thus not adequately described by conventional continuum plasticity theory. Discrete dislocation plasticity simulations have proven to be capable of capturing size-dependent plasticity in various situations, including (sub)micron-indentation with single indenters [1][2][3][4]. Recent models of contact between elastic-plastic rough surfaces have shown that interactions between neighboring asperity contacts play a critical role in determining the true area of contact between the surfaces [5][6][7].…”

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confidence: 99%

“…These predictions are based on classical plasticity theory, and so neglect any additional strengthening due to indentation size effects. Size effects for isolated contacts have been extensively studied both computationally [1][2][3] and experimentally [8,9]. Kim and co-workers have recently undertaken experimental studies on the evolution of multiasperity contact [10].…”

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confidence: 99%

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