Analytical and experimental determination of the material intrinsic length scale of strain gradient plasticity theory from micro- and nano-indentation experiments

Al‐Rub, Rashid K. Abu; Voyiadjis, George Z.

doi:10.1016/j.ijplas.2003.10.007

Cited by 305 publications

(127 citation statements)

References 108 publications

(265 reference statements)

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“…There are several possible reasons for this including: (i) the current twodimensional discrete dislocation plasticity simulations do not give rise to the square root Taylor relation on which Eq. (9) is based, although this can be included by using the extended set of constitutive rules suggested by Benzerga et al (2004); (ii) the indentation depths in the calculations presented here are restricted to dp0:4 mm and, as discussed by Abu Al-Rub and Voyiadjis (2004), the Nix and Gao (1998) model is most appropriate for indentation depths d41 mm; (iii) the models of Nix and Gao (1998) and of Huang et al (2006) essentially assume no interaction between the statistically stored and geometrically necessary dislocations and this interaction occurs naturally in the discrete dislocation plasticity calculations; (iv) the Nix and Gao (1998) and Huang et al (2006) models assume a hemispherical plastic zone with a radius equal to the nominal contact radius and the single crystal discrete dislocation calculations (see Fig. 7a) give a much larger plastic zone size; and…”

Section: Article In Pressmentioning

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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Section: Article In Pressmentioning

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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“…When indentation depth is d 1 = 10/30 the friction that occurs in most of the contact region is governed by plastic friction rather than Coulomb friction. In short, both plastic and Coulomb sliding does not take place in the initial indentation A number of experiments on indentation tests [25][26][27][28][29] show that when the metallic material characteristic length scale is on the order of the micrometer or submicron scale, plastic deformation is size-dependent. Classic plasticity theories could not explain size effects and strain gradient theories (see References in Ref.…”

Section: Plastic Sliding During Indentationmentioning

confidence: 99%

Tribology behavior during indentation and scratch of thin films on substrates: effects of plastic friction

Feng

Chen

2015

AIP Advances

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When friction stress on a contact surface reaches material yield strength in shear, contact slippage can occur even if the slipping condition for Coulomb friction is not satisfied. In this paper, a three-dimensional (3-D) scratch model is proposed, which considers combined Coulomb and plastic friction. Influences of plastic friction are discussed for two continuous displacement loading steps: indentation and scratch. For indentation, initially the sliding on the contact surface can not take place and the complete cohesion condition should be employed; then as the indenter is further compressed down to the coating surface, plastic friction instead of Coulomb friction prevails in most of the contact region. For scratch, the previous complete cohesion at the initial indentation is substituted by plastic or Coulomb slipping, and the slippage becomes plastic-sliding governed for a slightly large indentation depth. The effects of the indentation depth and the Coulomb friction coefficient on the scratch friction coefficient are discussed in detail. Several experimental phenomena are interpreted, which include that with an increase of the normal loading, the scratch friction coefficient reduces for the soft coating but grows for the hard coating; and with the growth of hardness after heat treatment, the scratch friction coefficient increases due to weak plastic slippage. Obtained results help to elucidate tribological behaviors during scratch and are helpful for the interpretation of experimental phenomena and the improvement of numerical simulations for the scratch process.

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“…Since the local and nonlocal metallurgical states also determine the phase transformation progress, the metallurgical variable (local term) and the first and second gradient of (nonlocal terms: ∇ , Δ ) are introduced. In line with [42], a linear coupling of the local and nonlocal terms associated with the metallurgical variable is introduced here (see (12)). During transformations of this kind, a hardening process occurs [7], which is simulated here by the term 1 where 1 denotes the linear isotropic hardening coefficient (which is a dimension of a stress) [8,10].…”

Section: Comments (I)mentioning

confidence: 99%

On a New Kinetic Modelling Approach of the Irreversible Quasi-Surface Metallurgical Phase Transformations

Antoni

2014

Journal of Solid State Physics

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Irreversible quasi-surface metallurgical phase transformations are the specific response of some metallic materials-such as metals and alloys-subjected to high thermomechanical loads applied very near their surface during the manufacturing processes or after being put into operation. These solid/solid phase transformations can be observed, for example, on the tread of many rails in railroad networks frequented by freight trains. The severe thermal and mechanical loads imposed on the surface of the rails and in the immediate vicinity of the surface by the wheel/rail contact often result in highly localized irreversible metallurgical transformations. A new kinetic model based on a previous study is presented here, which accounts more realistically for the nucleation and growth of these irreversible solid/solid phase transformations resulting from high thermomechanical loads. This metallurgical behavioral model was developed in the framework of continuum thermodynamics with gradients of temperature and internal variables.

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Analytical and experimental determination of the material intrinsic length scale of strain gradient plasticity theory from micro- and nano-indentation experiments

Cited by 305 publications

References 108 publications

Discrete dislocation plasticity analysis of the wedge indentation of films

Discrete dislocation plasticity analysis of the wedge indentation of films

Tribology behavior during indentation and scratch of thin films on substrates: effects of plastic friction

On a New Kinetic Modelling Approach of the Irreversible Quasi-Surface Metallurgical Phase Transformations

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