Role of discrete intragranular slip on lattice rotations in polycrystalline Ni: Experimental and micromechanical studies

Perrin, C.; Berbenni, Stéphane; Vehoff, H.; Berveiller, M.

doi:10.1016/j.actamat.2010.04.033

Cited by 29 publications

(10 citation statements)

References 38 publications

(47 reference statements)

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“…Ni has a relatively high elastic anisotropy factor with A ¼ 2:37 A ¼ 2C 44 C 11 ÀC 12 . It also presents the advantage of easy observation of slip lines [22,35]. Specimen plates 2 mm thick were heat treated at different temperatures ranging from 1200 to 1400°C for $3 days in order to produce a fully recrystallized microstructure with a maximum grain size of 5 mm and GBs more or less normal to the top surface.…”

Section: Materials Preparationmentioning

confidence: 99%

Incompatibility stresses at grain boundaries in Ni bicrystalline micropillars analyzed by an anisotropic model and slip activity

et al. 2015

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Incompatibility stresses can develop in bicrystals due to material elastic and plastic anisotropies owing to different crystal orientations separated by grain boundaries. Here, these stresses are investigated by combining experimental and theoretical studies on 10 lm diameter Ni bicrystalline micropillars. Throughout stepwise compression tests, slip traces are analyzed by scanning electron microscopy to identify the active slip planes and directions in both crystals. An analytical model is presented accounting for the effects of heterogeneous elasticity coupled to heterogeneous plasticity on the internal mechanical fields. This model provides explicit expressions of stresses in both crystals considering experimentally observed nonequal crystal volume fractions and inclined grain boundaries. It is used to predict the resolved shear stresses on the possible slip systems in each crystal. The predictions of the onset of plasticity as given by the present model in pure elasticity are compared with those given by the classical Schmid's law. In contrast with Schmid's law, the predictions of the analytical model are in full agreement with the experimental observations regarding the most highly stressed crystal and active slip systems. The effects of plastic incompatibilities are also considered in addition to the elastic ones throughout the model. The analysis shows that elastic/plastic coupling incompatibilities together with different crystal volume fractions have significant effects on the slip system activation process.

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Section: Materials Preparationmentioning

confidence: 99%

Incompatibility stresses at grain boundaries in Ni bicrystalline micropillars analyzed by an anisotropic model and slip activity

et al. 2015

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“…The experimentally observed lattice curvature at grain boundaries [16][17][18] is successfully accounted for in strain gradient plasticity models [19][20][21][22] or higher-order continua models [23][24][25][26], which are motivated by the need for describing Geometrically Necessary Dislocations (GNDs) [27]. Among possible applications of such models, the study of plasticity in the vicinity of crack tips [18], Hall-Petch effects [23,[28][29][30][31][32][33] or even grain size effects on plastic strain localization patterns [34] can be cited. The latter phenomena are observed at scales of about one micrometer, consistent with the predictions of several numerical works [30,[35][36][37][38].…”

Section: Introductionmentioning

confidence: 99%

Slip activities in polycrystals determined by coupling DIC measurements with crystal plasticity calculations

Guery

Hild

Latourte

et al. 2016

International Journal of Plasticity

105

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The role of crystallographic grain size and microstructure of an austenitic stainless steel (A316LN) is studied via in-situ mechanical testing in an SEM and digital image correlation to measure displacement and strain fields. The latter ones are directly measured on a mesh supported by the grain boundaries as imaged by EBSD. This experimental analysis is applied to five microstructures of the same cast material but subjected to different heat treatments. Differences in the strain distributions that can be attributed to the grain size are observed. The full-field measurements allow in turn for a direct, local and quantitative comparison with crystal plasticity finite element simulations of the same experiments based on the same mesh. A weak correlation between the plastic strain and the Schmid's factors, which are computed with macroscopic or even local stress evaluations, emphasizes the role of inter-grain strain incompatibilities or grain boundaries. However, a good agreement in the major slip system evaluation between experimental observation and computations is observed.

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“…These intra-granular spatial gradients of lattice orientation, e.g. lattice curvatures, can be measured with Electron Back-Scatterred Diffraction (EBSD) (Randle et al, 1996;Scheriau and Pippan, 2008;Beausir et al, 2009;Perrin et al, 2010). Using the relationship between lattice curvature and the GND density tensor (also called Nye tensor) given by Nye (1953) and later by Kröner (1958) or Kröner (1981), GND densities in polycrystalline metals are nowadays commonly measured using white beam micro-diffraction (Barabash et al, 2005) or using scanning electron microscopy equipped with two-or three-dimensional EBSD set up (Pantleon, 2008;Calcagnotto et al, 2010;Allain-Bonasso et al, 2012;Konijnenberg et al, 2015;Jiang et al, 2015;Wallis et al, 2016).…”

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confidence: 99%

A fast Fourier transform-based mesoscale field dislocation mechanics study of grain size effects and reversible plasticity in polycrystals

Berbenni

Taupin

Lebensohn

2020

Journal of the Mechanics and Physics of Solids

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To cite this version:Stéphane Berbenni, Vincent Taupin, Ricardo Lebensohn. A fast Fourier transform-based mesoscale field dislocation mechanics study of grain size effects and reversible plasticity in polycrystals. AbstractA numerical implementation of a non-local polycrystal plasticity theory based on a mesoscale version of the field dislocation mechanics theory (MFDM) of Acharya and Roy (2006) is presented using small-strain elasto-viscoplastic fast Fourier transformbased (EVPFFT) algorithm developed by Lebensohn et al. (2012). In addition to considering plastic flow and hardening only due to SSDs (statistically stored dislocations) as in the classic EVPFFT framework, the proposed method accounts for the evolution of GND (geometrically necessary dislocations) densities solving a hyperbolic-type partial differential equation, and GND effects on both plastic flow and hardening. This allows consideration of an enhanced strain-hardening law that includes the effect of the GND density tensor. The numerical implementation of a reduced version of the MFDM is presented in the framework of the FFT-based augmented Lagrangian procedure of Michel et al. (2001). A Finite Differences scheme combined with discrete Fourier transforms is applied to solve both incompatibility and equilibrium equations. The numerical procedure named MFDM-EVPFFT is used to perform full field simulations of polycrystal plasticity considering different grain sizes and their mechanical responses during monotonic tensile and reversible tension-compression tests. Using Voronoi tessellation and periodic boundary conditions, voxelized representative volume elements (RVEs) with different grain sizes are generated. With MFDM-EVPFFT, a Hall-Petch type scaling law is obtained in contrast with the conventional crystal plasticity EVPFFT. In the case of reversible plasticity, a stronger Bauschinger effect is observed with the MFDM-EVPFFT approach in comparison with conventional EVPFFT. The origin of these differences is analyzed in terms of heterogeneity, GND density and stress evolutions during the compression stage.

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Role of discrete intragranular slip on lattice rotations in polycrystalline Ni: Experimental and micromechanical studies

Cited by 29 publications

References 38 publications

Incompatibility stresses at grain boundaries in Ni bicrystalline micropillars analyzed by an anisotropic model and slip activity

Incompatibility stresses at grain boundaries in Ni bicrystalline micropillars analyzed by an anisotropic model and slip activity

Slip activities in polycrystals determined by coupling DIC measurements with crystal plasticity calculations

A fast Fourier transform-based mesoscale field dislocation mechanics study of grain size effects and reversible plasticity in polycrystals

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