Grain-boundary sliding and diffusion creep in polycrystalline solids

Stevens, R. N.

doi:10.1080/14786437108216383

Cited by 97 publications

(14 citation statements)

References 11 publications

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“…[29,30] The present experimental results at low stresses are consistent with the idea that there is extensive GBS during diffusion creep, with values of the GBS contribution to creep n ‡ 60 pct. [9,31] The absence of slip markings on polished specimen surfaces and the retention of straight marker lines within grains also indicate that there is very little intragranular dislocation activity in this region. Microstructural data summarized in Figure 3(a) also indicate that most boundaries experience some GBS during creep at low stresses.…”

Section: A Gbs During Diffusion Creepmentioning

confidence: 94%

Grain Boundary Sliding during Diffusion and Dislocation Creep in a Mg-0.7 Pct Al Alloy

Kottada

Chokshi

2007

Metall Mater Trans A

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Early studies on grain boundary sliding (GBS) in Mg alloys have suggested frequently that the contribution of GBS to creep is high even under conditions corresponding to dislocation creep. The role of creep strain and grain size in influencing the experimental measurements has not been clearly identified. Grain boundary sliding measurements were conducted in detail over experimental conditions corresponding to diffusion creep as well as dislocation creep in a singlephase Mg-0.7 wt pct Al alloy. The results indicated clearly that the GBS contribution to creep was very high during diffusion creep at low stresses (~75 pct) and substantially reduced during dislocation creep at high stresses (~15 pct). These measurements were consistent with the observation of significant intragranular slip band activity observed in most grains at high stresses and very little slip band activity at low stresses. The experimental measurements and analysis indicated also that the GBS contribution to creep was high during the initial stages of creep and decreased to a steady-state value at large strains.

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Section: A Gbs During Diffusion Creepmentioning

confidence: 94%

Grain Boundary Sliding during Diffusion and Dislocation Creep in a Mg-0.7 Pct Al Alloy

Kottada

Chokshi

2007

Metall Mater Trans A

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“…McNelley et al [56] reported that the Solute Drag Creep mechanism is dominant at higher strain rate (~10 −1 s −1 ) whereas governing deformation mechanism at lower strain rate (~10 −1 s −1 ) is GBS. Further information on a range of aspects of superplastic deformation mechanism may also be found in Grimes et al [38], Stevens et al [150], Prabu et al [151], Mukherjee et al [152], and Sergueeva et al [153].…”

Section: Superplastic Deformation Mechanismsmentioning

confidence: 99%

Recent Development of Superplasticity in Aluminum Alloys: A Review

Bhatta

Pesin

Zhilyaev

et al. 2020

Metals

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Aluminum alloys can be used in the fabrication of intricate geometry and curved parts for a wide range of uses in aerospace and automotive sectors, where high stiffness and low weight are necessitated. This paper outlines a review of various research investigations on the superplastic behavior of aluminum alloys that have taken place mainly over the past two decades. The influencing factors on aluminum alloys superplasticity, such as initial grain size, deformation temperature, strain rate, microstructure refinement techniques, and addition of trace elements in aluminum alloys, are analyzed here. Since grain boundary sliding is one of the dominant features of aluminum alloys superplasticity, its deformation mechanism and the corresponding value of activation energy are included as a part of discussion. Dislocation motion, diffusion in grains, and near-grain boundary regions being major features of superplasticity, are discussed as important issues. Moreover, the paper also discusses the corresponding values of grain size exponent, stress exponent, solute drag creep and power law creep. Constitutive equations, which are essential for commercial applications and play a vital role in predicting and analyzing the superplastic behavior, are also reviewed here.

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“…[3] For micron-sized grains, GBS becomes an important deformation mechanism for elevated temperature forming, such as quick plastic forming or superplastic forming. [4][5][6][7][8][9][10][11][12] It is important to understand how to modify the chemistry at GBs through solute alloy additions to increase the contribution of GBS to total deformation so that the extra processes for refining grain sizes can be avoided. Extensive experimental evidence has suggested that GB chemistry plays an important role in controlling GBS.…”

Section: Introductionmentioning

confidence: 99%

The Effect of Solute Atoms on Aluminum Grain Boundary Sliding at Elevated Temperature

Krajewski

et al. 2010

Metall Mater Trans A

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Grain boundary sliding (GBS) is an important deformation mechanism for elevated temperature forming processes. Molecular dynamics simulations are used to investigate the effect of solute atoms in near grain boundaries (GBs) on the sliding of Al bicrystals at 750 K (477°C). The threshold stress for GBS is computed for a variety of GBs with different structures and energies. Without solute atoms, low-energy GBs tend to exhibit significantly less sliding than high-energy GBs. Simulation results show that elements which tend to phase segregate from Al, such as Si, can enhance GBS in high-energy GBs by weakening Al bonds and by increasing atomic mobility. In comparison, intermetallic forming elements, such as Mg, will form immobile Mg-Al clusters, decrease diffusivity, and inhibit GBS.

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Grain-boundary sliding and diffusion creep in polycrystalline solids

Cited by 97 publications

References 11 publications

Grain Boundary Sliding during Diffusion and Dislocation Creep in a Mg-0.7 Pct Al Alloy

Grain Boundary Sliding during Diffusion and Dislocation Creep in a Mg-0.7 Pct Al Alloy

Recent Development of Superplasticity in Aluminum Alloys: A Review

The Effect of Solute Atoms on Aluminum Grain Boundary Sliding at Elevated Temperature

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