Modeling dislocation sources and size effects at initial yield in continuum plasticity

Puri, Saurabh; Roy, Anish; Acharya, Amit; Dimiduk, Dennis M.

doi:10.2140/jomms.2009.4.1603

Cited by 15 publications

(10 citation statements)

References 26 publications

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“…In this theory, mesoscopic plasticity is modeled as an extension of conventional plasticity, which accounts for the effects of dislocation stresses as well as their spatiotemporal evolution in a physically meaningful averaged sense. Numerical results obtained from a finite element implementation of MFDM are in good qualitative agreement with experimental observations and some of the key physically relevant problems has been successfully solved and documented [9,10,11]. Motivated by the experimental observations [4,5], the effect of surface passivation, grain orientation, grain boundary constraints, and film thickness on the mechanical response of multicrystalline thin films is studied using MFDM in [12].…”

Section: Introductionsupporting

confidence: 59%

Plastic deformation of multicrystalline thin films: Grain size distribution vs. grain orientation

Puri

Roy

2012

Computational Materials Science

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A continuum model of plasticity, Mesoscopic Field Dislocation Mechanics (MFDM), is used to study the interplay between grain size and grain orientation on the mechanical response of multicrystalline thin films undergoing plane strain tension. It is shown that the grain size dependence in the case of multicrystals is controlled by those grains which are relatively more susceptible to plastic deformation. This effect is captured to some extent by conventional crystal plasticity theory; however, the explicit incorporation of polar dislocations in the MFDM model significantly enhances the overall mechanical response as demonstrated in the paper.

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Section: Introductionsupporting

confidence: 59%

Plastic deformation of multicrystalline thin films: Grain size distribution vs. grain orientation

Puri

Roy

2012

Computational Materials Science

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“…This was done with finite elements in Acharya (2005, 2006) and in Varadhan et al (2006). Different size effects for single crystalline materials and multicrystalline thin films have been predicted with the MFDM theory as reported in Roy and Acharya (2006), Puri et al (2009) andPuri et al (2011). Grain size distribution and crystallographic orientation effects in multicrystalline thin films were discussed in Puri and Roy (2012).…”

mentioning

confidence: 80%

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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“…These excess dislocations cause plastic deformation in the nonsource regions. This mechanism of modeling dislocation sources in the context of PMFDM is explained in detail in Puri et al [12] In this particular case, the left crystal has the cube orientation, whereas the right crystal is misoriented by 5 deg about the X 3 -axis. Material properties, representative of copper, as described earlier in Section IV, are used in this case, except the rate sensitivity for nonsource regions is set at 1.0 (=m) and 0.03 for source regions.…”

Section: A Grain Boundary As a Sourcementioning

confidence: 99%

Controlling Plastic Flow across Grain Boundaries in a Continuum Model

Puri

Acharya

Rollett

2010

Metall Mater Trans A

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A framework for modeling controlled plastic flow through grain boundaries using a continuum plasticity theory, phenomenological mesoscopic field dislocation mechanics (PMFDM), is presented in this article. The developed tool is used to analyze the effect of different classes of constraints to plastic flow through grain boundaries, as it relates to dislocation microstructure development and mechanical response of a bicrystal. It is found that in the case of low misorientation angle between adjacent grains, impenetrable grain boundaries cause significant work hardening as compared to penetrable grain boundaries due to the accumulation of excess dislocations along them. However, a penetrable grain boundary with a high misorientation angle effectively behaves as an impenetrable boundary, with respect to the stress-strain response.

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Modeling dislocation sources and size effects at initial yield in continuum plasticity

Cited by 15 publications

References 26 publications

Plastic deformation of multicrystalline thin films: Grain size distribution vs. grain orientation

Plastic deformation of multicrystalline thin films: Grain size distribution vs. grain orientation

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

Controlling Plastic Flow across Grain Boundaries in a Continuum Model

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