Superplastic deformation mechanisms in fine-grained Al–Mg based alloys

Mikhaylovskaya, A. V.; Yakovtseva, O. A.; Golovin, I.S.; Поздняков, А. В.; Portnoy, V.K.

doi:10.1016/j.msea.2014.12.099

Cited by 55 publications

(25 citation statements)

References 39 publications

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“…If the climb distance is of only core size of the grain, it would climb through the lattice and act as rate controlling process [46]. The superplasticity of AA 5083 alloy with and without Cr of grain sizes 7 and 10 μm was studied by Mikhaylovskaya et al [47]. The elongation in alloy with Cr is found to be marginally higher than the alloy without Cr attributed to it difference in the grain size.…”

Section: Fine-grained Superplasticitymentioning

confidence: 99%

Effect of Grain Size on Superplastic Deformation of Metallic Materials

Raja¹,

Jayaganthan²,

Tiwari³

et al. 2020

Aluminium Alloys and Composites

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The superplastic deformation exhibited by metals with different grain sizes and their corresponding deformation mechanism influences the industrial metalforming processes. The coarse-grained materials, which contain grain size greater than 20 μm, exhibited superplastic deformation at high homologous temperature and low strain rate of the order of 10 −4 s −1. Fine grain materials (1-20 μm) are generally considered as favorable for superplastic deformation. They possess highstrain-rate sensitivity "m" value, approximately, equal to 0.5 at the temperature of 0.5 times the melting point and at a strain rate of 10 −3 to 10 −4 s −1. Ultrafine grains (100 nm to less than 1 μm) exhibit superplasticity at high strain rate as well as at low temperature when compared to fine grain materials. It is attributed to the fact that both temperature and strain rates are inversely proportional to the grain size in Arrhenius-type superplastic constitute equation. The superplastic phenomenon with nano-sized grains (10 nm to less than 100 nm) is quite different from their higher-scale counterparts. It exhibits high ductility with high strength. Materials with mixed grain size distribution (bimodal or layered) are found to exhibit superior superplasticity when compared to the homogeneous grain-sized material. The deformation mechanisms governing these superplastic deformations with different scale grain size microstructures are discussed in this chapter.

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Section: Fine-grained Superplasticitymentioning

confidence: 99%

Effect of Grain Size on Superplastic Deformation of Metallic Materials

Raja¹,

Jayaganthan²,

Tiwari³

et al. 2020

Aluminium Alloys and Composites

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“…A high dislocation density at the beginning of the deformation at T = 400 • C with a high strain rate caused by grain adaptation-i.e., where the dislocation density increased rapidly and was plugged into the grain-formed dislocation walls/cells and led to increased true stress [25]. However, with the accumulation of deformations, the grain rotation occurred under shear stress and dislocations were absorbed by the grain boundaries, which led to the true stress remaining stable for a short period of time [26]. This is the reason for the true stress presenting in a step-up state.…”

Section: Figure 1amentioning

confidence: 99%

Cavity Behavior of Fine-Grained 5A70 Aluminum Alloy during Superplastic Formation

Jin

Zhong-guo

2018

Metals

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The study of the exact physical mechanism of cavity nucleation and growth is significant in terms of predicting the extent of internal damage following superplastic deformation. The 5A70 alloy was processed by cold rolling for 14 passes with a total reduction deformation of 90% (20–2 mm) and the heat treatment was inserted at a thickness of 10 and 5 mm at 340 °C for 30 min. The superplastic tensile tests were performed at 400, 450, 500, 550 °C and the initial strain rate was 1 10−3 s−1. Cavities were observed at the head of the particle and the interface of the grain boundaries. It is suggested that the cavity was nucleated during the sliding/climbing of the dislocations, due to the precipitate pinning effect and the impeding grain boundary during grain boundary sliding (GBS). In this study, the results demonstrated a clear transition from diffusion growth to superplastic diffusion growth and plastic-controlled growth at a cavity radius larger than 1.52 and 13.90 μm. The cavity nucleation, growth, interlinkage and coalescence under the applied stress during the superplastic deformation, as well as the crack formation and expansion during the deformation, ultimately led to the superplastic fracture.

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“…Specifically, an extensive development of dynamic recrystallization has been found [e.g. [4][5][6][7][8]. So far, however, such studies are still limited.…”

Section: Introductionmentioning

confidence: 99%

EBSD study of superplastically strained Al-Mg-Li alloy

et al. 2020

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In this study, electron back scatter diffraction (EBSD) was employed to examine the microstructure evolved during superplastic deformation of advanced Al-Mg-Li alloy. In contrast to the widelyaccepted conception of superplasticity, the microstructure was found to be characterized by elongated grains, a notable fraction of low-angle boundaries, and a distinct (though a very weak) crystallographic texture. All these observations suggested a significant activity of intragranular slip.

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Superplastic deformation mechanisms in fine-grained Al–Mg based alloys

Cited by 55 publications

References 39 publications

Effect of Grain Size on Superplastic Deformation of Metallic Materials

Effect of Grain Size on Superplastic Deformation of Metallic Materials

Cavity Behavior of Fine-Grained 5A70 Aluminum Alloy during Superplastic Formation

EBSD study of superplastically strained Al-Mg-Li alloy

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