Evolution of initial grain boundaries and shear bands in Cu bicrystals during one-pass equal-channel angular pressing

Han, Wei‐Zhong; Yang, H.J.; An, Xianghai; Yang, Rui; Li, S X; Sheng, Wu; Zhang, Zhefeng F

doi:10.1016/j.actamat.2008.11.001

Cited by 31 publications

(9 citation statements)

References 46 publications

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“…It has been commonly remarked that the study of the behavior of a polycrystalline material is often reduced to exploring those of the interfaces [1]. Grain boundaries (GBs), one of the most important interface structures in polycrystalline materials, impact the bulk properties in many aspects [1][2][3][4][5][6][7].…”

Section: Introductionmentioning

confidence: 99%

Deformation and spallation of shocked Cu bicrystals withΣ3 coherent and symmetric incoherent twin boundaries

Han

Luo

et al. 2012

Phys. Rev. B

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We perform molecular dynamics simulations of Cu bicrystals with two important GBs, Σ3 coherent twin boundaries (CTB) and symmetric incoherent twin boundaries (SITB), under planar shock wave loading. It is revealed that the shock response (deformation and spallation) of the Cu bicrystals strongly depends on the GB characteristics. At the shock compression stage, elastic shock wave can readily trigger GB plasticity at SITB but not at CTB. The SITB can induce considerable wave attenuation such as the elastic precursor decay via activating GB dislocations. For example, our simulations of a Cu multilayer structure with 53 SITBs (~1.5 µm thick) demonstrate a ~80% elastic shock decay. At the tension stage, spallation tends to occur at CTB but not at SITB due to the high mobility of SITB. The SITB region transforms into a threefold twin via a sequential partial dislocation slip mechanism, while CTB preserves its integrity before spallation. In addition, deformation twinning is a mechanism for inducing surface step during shock tension stage. The drastically different shock response of CTB and SITB could in principle be exploited for, or benefit, interface engineering and materials design.

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Section: Introductionmentioning

confidence: 99%

Deformation and spallation of shocked Cu bicrystals withΣ3 coherent and symmetric incoherent twin boundaries

Han

Luo

et al. 2012

Phys. Rev. B

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“…Increasing rates of £ during deformation can be calculated using experimental conditions and results, and these are about 10 ¹2 s ¹1 . The amount of simple shear deformation by 1-pass ECAP processing is known to be about 2, 3,26) which implies that simple shear deformation as much as £ = 0.6 in the shear band of a notched specimen at ¾ ap = 0.07 corresponds to 30% of simple shear deformation per pass of ECAP.…”

Section: Evaluation Of Shear Amount Inside Shear Bandmentioning

confidence: 99%

SEM/EBSD Analysis of Grain Refinement and Coarsening of Ultra-Fine-Grained Al during Simple Shear Deformation

et al. 2021

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Although severe plastic deformation causes grain refinement of polycrystalline materials, saturation of grain refinement is known to be caused by simultaneous grain coarsening. In the present study, for ultra-fine-grained (UFG) pure Al prepared by equal-channel angular pressing, we studied the grain refinement and coarsening processes during large simple-shear deformation using scanning electron microscopy/electron backscatter diffraction. The changes of the crystal orientations in the grains as a function of position were analyzed using log angles as rotation angles around reference axes. This analysis enabled the evaluation of order of magnitude of the in-plane components of geometrically necessary dislocation (GND) density tensors. Detailed changes in the crystal orientations during shear deformation were measured for identical regions in UFG Al, and the changes in the components of the GND density tensors were discussed. Our findings indicate that the grain refinement and coarsening can be explained by the appearance and disappearance of grain boundaries composed of dislocation walls, respectively.

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“…Research activity in the area of severe plastic deformation (SPD) has increased tremendously in recent years because of the many interesting properties that can be achieved in bulk materials by SPD [1][2][3]. Equal channel angle pressing (ECAP) is an extremely effective SPD bulk super ultrafine-grained materials preparation method that has been deeply researched in this decade [4,5]. In these studies, most of the focus was aimed at the grain refining mechanism and refining results at different strains during ECAP [6][7][8][9], but scarcely on the deformation temperature rise effect on the microstructure of the materials.…”

Section: Introductionmentioning

confidence: 99%

Numerical and Experimental Study of Temperature Rise Effect on Copper during Equal Channel Angular Pressing

Guo

Cao

Ding

et al. 2016

MSF

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The temperature rising of pure copper during equal channel angular pressing (ECAP) was investigated based on the soft DEFORM 3D. The simulation results were compared with test results, and the microstructure evolution and recrystallization process was analyzed. The experimental results showed that under the same deformation conditions, different initial states of materials had different deformation temperature raised, with which the strain state further affected the recrystallization process. In the certain scope of die channel angle, it will have an optimal grainrefinement effect. As strain increased, the material microstructure engendered a non-equilibrium structure at the macro level, and recrystallization became complicated. Control ECAP deformation parameters had an observable effect on grain refinement. After plastic deformation, the parameters of the material’s state, die structure and deformation temperature determined the material’s grain size limit. The simulated results agreed well with the experimental results.

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Evolution of initial grain boundaries and shear bands in Cu bicrystals during one-pass equal-channel angular pressing

Cited by 31 publications

References 46 publications

Deformation and spallation of shocked Cu bicrystals withΣ3 coherent and symmetric incoherent twin boundaries

Deformation and spallation of shocked Cu bicrystals withΣ3 coherent and symmetric incoherent twin boundaries

SEM/EBSD Analysis of Grain Refinement and Coarsening of Ultra-Fine-Grained Al during Simple Shear Deformation

Numerical and Experimental Study of Temperature Rise Effect on Copper during Equal Channel Angular Pressing

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