Analysis of the cooperative grain boundary sliding in terms of cellular dislocations

Zelin, M. G.; Mukherjee, Amiya K.

doi:10.1080/01418619308222926

Cited by 16 publications

(8 citation statements)

References 21 publications

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“…8͑a͒. This picture reveals mesoscale cooperative grain boundary sliding 39 by the microscale mechanisms of grain boundary sliding, migration, and rotation, as shown in Fig. 6.…”

Section: Intergranular Deformation In Nanocrystalline Metalsmentioning

confidence: 95%

Grain-size dependence of the relationship between intergranular and intragranular deformation of nanocrystalline Al by molecular dynamics simulations

2005

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The strength of nanocrystalline aluminum has been studied using molecular dynamics simulation. Nanocrystalline models consisting of hexagonal grains with grain size d between 5 nm and 80 nm are deformed by the application of tension. A transition from grain-size hardening to grain-size softening can be observed in the region where d Ϸ 30 nm, which is the optimum grain size for strength. In the grain-size hardening region, nanocrystalline models primarily deform by intragranular deformation. Consequently, a pile-up of dislocations can be observed. When the grain size becomes less than 30 nm, where the thickness of the grain boundaries cannot be neglected in comparison to the grain sizes, the dominant deformation mechanism of nanocrystalline metals is intergranular deformation by grain boundary sliding. Further, geometrical misfits by grain boundary sliding are accommodated by the grain rotation mechanism. Moreover, cooperative grain boundary sliding occurs in the 5 nm model. The optimum grain size is controlled by the relationship between resistance to intergranular deformation by grain boundary processes and intragranular deformation resisted by the grain boundary. Therefore, the primary role of the grain boundary changes in the region where the optimum grain size is observed.

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“…8͑a͒. This picture reveals mesoscale cooperative grain boundary sliding 39 by the microscale mechanisms of grain boundary sliding, migration, and rotation, as shown in Fig. 6.…”

Section: Intergranular Deformation In Nanocrystalline Metalsmentioning

confidence: 95%

Grain-size dependence of the relationship between intergranular and intragranular deformation of nanocrystalline Al by molecular dynamics simulations

2005

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“…25,26) Concurrently, the easier shifting of grain groups in recrystallized areas as a unit begins to occur along common grain boundary surfaces (Fig. 8(a)).…”

Section: Discussionmentioning

confidence: 99%

“…7(a) that GBS occurs in a individual manner throughout the sliding of individual grains in recrystallized areas and, in contrast, along separate boundaries in unrecrystallized areas. There is an evidence for operation of GBS in a cooperative manner through the shift of grain groups as a unit relative to each other along common grain boundary surfaces 25,26) which propagate into the unrecrystallized areas. These surfaces locate at angles ranging from 60 to 85 deg to the tension axis.…”

Section: Surface Observationsmentioning

confidence: 99%

The Role of Grain Boundary Sliding in Microstructural Evolution during Superplastic Deformation of a 7055 Aluminum Alloy

et al. 2002

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The microstructure evolution in a 7055 aluminum alloy subjected to thermomechanical processing (TMP) was studied at 450 • C anḋ ε = 1.7 × 10 −3 s −1 at which the material exhibits superplastic behavior with a total elongation of 720% and the coefficient m = 0.58. Partially recrystallized initial structure of the as-processed 7055 Al consisted of bands of recrystallized grains with a mean size of 11 µm alternating with bands of recovered subgrains with a mean size of 2 µm. The true stress-true strain curve exhibits a well-defined peak stress, followed by gradual strain softening. The coefficient of strain rate sensitivity, m, remains unchanged at ε ≤ 1 and tends to decrease with strain at ε > 1. The initial microstructure persists near the peak strain. Following strain leads to evolution of initial partially recrystallized structure into uniform fully recrystallized structure due to occurrence of continuous dynamic reactions, i.e. continuous dynamic recrystallization (CDRX). The data of microstructural observation and misorientation analysis show that low-angle boundaries (LAB) gradually convert to high-angle boundaries (HAB) resulting in an extensive flow softening. It was shown that grain boundary sliding (GBS) provides superplastic flow at all strains. Concurrently, GBS plays an important role in the dynamic evolution of new grains facilitating conversion of LABs to HABs.

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“…Importantly, such grain boundary sliding may occur in a coordinated way [27,[105][106][107][113][114][115]. For example, shown in Fig.…”

Section: Grain Boundary Slidingmentioning

confidence: 99%

Deformation twinning in nanocrystalline materials

Zhu

Liao

2012

Progress in Materials Science

1,110

447

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Analysis of the cooperative grain boundary sliding in terms of cellular dislocations

Cited by 16 publications

References 21 publications

Grain-size dependence of the relationship between intergranular and intragranular deformation of nanocrystalline Al by molecular dynamics simulations

Grain-size dependence of the relationship between intergranular and intragranular deformation of nanocrystalline Al by molecular dynamics simulations

The Role of Grain Boundary Sliding in Microstructural Evolution during Superplastic Deformation of a 7055 Aluminum Alloy

Deformation twinning in nanocrystalline materials

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