Comparison between superplastic deformation mechanisms at primary and steady stages of the fine grain AA7475 aluminium alloy

Mikhaylovskaya, A. V.; Yakovtseva, O. A.; Ситкина, М. Н.; Котов, А. Д.; Иржак, А. В.; Krymskiy, S. V.; Portnoy, V.K.

doi:10.1016/j.msea.2018.01.102

Cited by 44 publications

(10 citation statements)

References 54 publications

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“…Possibility of dislocation creep as an accommodation mechanism along with dislocation creep is also suggested in this work. This detailed study on the comparison between primary and steady stage deformation by Mikhaylovskaya et al [40] elaborated and concurred with the work by Rao and Mukerjee [39].…”

Section: Fine-grained Superplasticitysupporting

confidence: 85%

“…It describes that diffusion creep is the deformation mechanism rate controlled by dislocation climb. Mikhaylovskaya et al [40] compared the superplastic deformation behavior in fine-grained Al 7475 alloy at primary stage and steady stage deformation. It was found that grain elongation occurred at primary stage due to diffusional creep, while at steady stage, diffusion creep becomes the accommodation process for GBS without any further change in the shape and size of the grain.…”

Section: Fine-grained Superplasticitymentioning

confidence: 99%

See 1 more Smart Citation

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 Superplasticitysupporting

confidence: 85%

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

View full text Add to dashboard Cite

show abstract

“…e early stage of superplastic deformation of Al alloys is usually accompanied with static/ dynamic grain growth and anisotropic grain elongation. It should be noticed that grains are more elongated in the tensile direction than in the transverse direction [53,54]. Yet, the static/dynamic grain growth is closely related to the distribution of intermetallic precipitates, which is fully discussed in Section 4.2.…”

Section: Superplastic Deformation Behaviormentioning

confidence: 97%

“…Generally speaking, superplastic deformation is mainly controlled by three mechanisms: grain-boundary sliding (GBS), dislocation slip/creep, and diffusion creep or directional diffusional flow [53]. Meanwhile, superplastic deformation is accompanied by various processes, for instance, grainboundary migrations and static/dynamic grain growth, grain rotation [80,99], recovery, recrystallisation, and polygonisation [87,100,101].…”

Section: Mechanisms Of Superplastic Deformationmentioning

confidence: 99%

A Review on Superplastic Formation Behavior of Al Alloys

Wang

et al. 2018

Advances in Materials Science and Engineering

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Superplastic formation technology is considered to be an effective and promising method to conquer formation difficulties of Al alloys, especially thin-walled or complex structure. In this paper, fundamentals of superplastic deformation of Al alloys are summarized and the superplastic deformation behaviors of main kinds of Al alloys are summarized and compared, including Al-Mg alloys, Al-Li alloys, and Al-Zn-Mg alloys as well as aluminum matrix composites. Then, the superplastic deformation mechanism for different Al alloys is thoroughly discussed. Last but not the least, the factors affecting the superplastic deformation process are fully analyzed.

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“…The precipitation-depleted zones (PDZ) were identified on both sides of the HAGB boundaries and in triple junctions (Figure 5g-i). This phenomenon typically associates with the diffusion creep mechanism that can accommodate the grain boundary sliding and be an important independent deformation mechanism [71].…”

Section: Subsectionmentioning

confidence: 99%

High Strain Rate Superplasticity in Al-Zn-Mg-Based Alloy: Microstructural Design, Deformation Behavior, and Modeling

et al. 2020

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Increasing the strain rate at superplastic forming is a challenging technical and economic task of aluminum forming manufacturing. New aluminum sheets exhibiting high strain rate superplasticity at strain rates above 0.01 s−1 are required. This study describes the microstructure and the superplasticity properties of a new high-strength Al-Zn-Mg-based alloy processed by a simple thermomechanical treatment including hot and cold rolling. The new alloy contains Ni to form Al3Ni coarse particles and minor additions of Zr (0.19 wt.%) and Sc (0.06 wt.%) to form nanoprecipitates of the L12-Al3 (Sc,Zr) phase. The design of chemical and phase compositions of the alloy provides superplasticity with an elongation of 600–800% in a strain rate range of 0.01 to 0.6/s and residual cavitation less than 2%. A mean elongation-to-failure of 400% is observed at an extremely high constant strain rate of 1 s−1. The strain-induced evolution of the grain and dislocation structures as well as the L12 precipitates at superplastic deformation is studied. The dynamic recrystallization at superplastic deformation is confirmed. The superplastic flow behavior of the proposed alloy is modeled via a mathematical Arrhenius-type constitutive model and an artificial neural network model. Both models exhibit good predictability at low and high strain rates of superplastic deformation.

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Comparison between superplastic deformation mechanisms at primary and steady stages of the fine grain AA7475 aluminium alloy

Cited by 44 publications

References 54 publications

Effect of Grain Size on Superplastic Deformation of Metallic Materials

Effect of Grain Size on Superplastic Deformation of Metallic Materials

A Review on Superplastic Formation Behavior of Al Alloys

High Strain Rate Superplasticity in Al-Zn-Mg-Based Alloy: Microstructural Design, Deformation Behavior, and Modeling

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