The non-equilibrium state of grain boundaries and the grain boundary precipitations in aluminium alloys

Valiev, Ruslan Z.; Musalimov, R. Sh.; Tsenev, Nikolai K.

doi:10.1002/pssa.2211150211

Cited by 66 publications

(43 citation statements)

References 7 publications

(1 reference statement)

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“…These observations agree with early experiments [135,136] and models [15] of non-equilibrium grain boundaries that suggested that SPD processing can trigger the interfaces to attain a non-equilibrium state as a result of heavy interaction with dislocations or imposed plasticity constraints.…”

Section: Discussionsupporting

confidence: 90%

Grain boundaries in ultrafine grained materials processed by severe plastic deformation and related phenomena

Sauvage

Wilde

Divinski

et al. 2012

Materials Science and Engineering: A

478

219

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Grain boundaries in ultrafine grained (UFG) materials processed by severe plastic deformation (SPD) are often called "non-equilibrium" grain boundaries. Such boundaries are characterized by excess grain boundary energy, presence of long range elastic stresses and enhanced free volumes. These features and related phenomena (diffusion, segregation, etc.) have been the object of intense studies and the obtained results provide convincing evidence of the importance of a non-equilibrium state of high angle grain boundaries for UFG materials with unusual properties. The aims of the present paper are first to give a short overview of this research field and then to consider tangled, yet unclear issues and outline the ways of oncoming studies. A special emphasis is given on the specific structure of grain boundaries in ultrafine grained materials processed by SPD, on grain boundary segregation, on interfacial mixing linked to heterophase boundaries and on grain boundary diffusion. The connection between these unique features and the mechanical properties or the thermal stability of the ultrafine grained alloys is also discussed.

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Section: Discussionsupporting

confidence: 90%

Grain boundaries in ultrafine grained materials processed by severe plastic deformation and related phenomena

Sauvage

Wilde

Divinski

et al. 2012

Materials Science and Engineering: A

478

219

View full text Add to dashboard Cite

show abstract

“…[6][7][8] UFG structures by SPD are mostly composed of deformation-induced grain boundaries, and these grain boundaries are regarded as none-equilibrium boundaries. [9][10][11] In deformation-induced grain boundaries, external grain boundary dislocation, or alternatively called extrinsic grain boundary dislocation, are comprised in grain boundaries lending grain boundaries energy higher than those at equilibrium state. This is evidenced by internal dislocations near the grain boundaries observed by transmission electron microscopy (TEM).…”

Section: Introductionmentioning

confidence: 99%

Corrosion of Ultrafine Grained Materials by Severe Plastic Deformation, an Overview

Miyamoto

2016

Mater. Trans.

117

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Corrosion of ultra ne grain (UFG) materials by severe plastic deformation (SPD) is reviewed in light of the existing literature and microstructural change. Fortunately, by holistic survey of the literature, it seems likely that grain re nement by SPD, while enhancing mechanical properties, does not compromise the overall corrosion resistance, and in many case, improve it in comparison with coarse-grained counterparts, although there are some contradictory results within the same materials and same environment. The degree of impact of UFG formation on corrosion is highest in stainless steels followed by aluminum and magnesium alloys whereas it is relatively marginal in pure copper and titanium. The effect of UFG formation by SPD on corrosion is imparted by not only grain re nement, but also other microstructural change occurring commonly in SPD in general and unique to each speci c SPD method. In this review, an attention is paid speci cally to the former case, and this includes shuf ing or redistribution of chemical inhomogeneity into a ner scale, deformation-induced grain boundaries and high internal stress stemming from these grain boundaries. The literature on stress corrosion cracking (SCC) of UFG materials are de nitely insuf cient to nd the general trends, more studies are waited.

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“…The potential for achieving superplasticity in metallic alloys processed by SPD was demonstrated in very early experiments conducted to examine the mechanical properties of materials after processing by HPT [36]. Subsequently, it was recognized that the inverse dependence on grain size raised to a power of p = 2 in Eq.…”

Section: The Characteristics Of Superplasticitymentioning

confidence: 99%

Developing Superplasticity in Ultrafine-Grained Metals

Kawasaki

Langdon

2015

Acta Phys. Pol. A

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The processing of bulk metals through the application of severe plastic deformation provides an opportunity for achieving exceptional grain renement with grain sizes typically lying in the submicrometer or even the nanometer range. Provided these small grains are reasonably stable at elevated temperatures, these ultrane-grained metals will exhibit excellent superplastic properties when pulled in tension at elevated temperatures. Most ultranegrained materials have been produced using either equal-channel angular pressing or high-pressure torsion. This paper examines the results for superplasticity reported to date using metallic alloys processed by equal-channel angular pressing and high-pressure torsion, compares the experimental strain rates with those predicted using the theoretical model for conventional superplastic ow and then demonstrates the feasibility of preparing deformation mechanism maps that provide comprehensive information on the ow mechanisms.

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The non-equilibrium state of grain boundaries and the grain boundary precipitations in aluminium alloys

Cited by 66 publications

References 7 publications

Grain boundaries in ultrafine grained materials processed by severe plastic deformation and related phenomena

Grain boundaries in ultrafine grained materials processed by severe plastic deformation and related phenomena

Corrosion of Ultrafine Grained Materials by Severe Plastic Deformation, an Overview

Developing Superplasticity in Ultrafine-Grained Metals

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