Optimizing the strength and ductility of fine structured 2024 Al alloy by nano-precipitation

Cheng, Sheng; Zhao, Yaohua; Zhu, Yuntian; Ma, E.

doi:10.1016/j.actamat.2007.06.043

Cited by 453 publications

(173 citation statements)

References 40 publications

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“…It was even proposed by some authors that a fine distribution of nanoscaled precipitates may act as sites for trapping and accumulating dislocations, leading to an increase of the strain hardening and subsequently to an increased ductility [59,60]. The main challenge is to control the precipitation kinetics in a situation where recrystallisation, grain growth, and heterogeneous precipitation along dislocations and/or grain boundaries are very likely to occur.…”

Section: Spd Induced Gb Segregationmentioning

confidence: 99%

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

488

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: Spd Induced Gb Segregationmentioning

confidence: 99%

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

488

219

View full text Add to dashboard Cite

show abstract

“…Cheng et al reported for a AA2024 [22] that workability at cryogenic temperatures benefits from remnant precipitates that were partially dissolved during an incomplete SSHT. This is in accordance with Lapovok et al [8] who also reported better RT-ECAE workability for annealed AA2124 compared to the SSHT condition.…”

Section: Materials Science Forum Vols 584-586 687mentioning

confidence: 99%

Combining Equal-Channel Angular Extrusion (ECAE) and Heat Treatment for Achieving High Strength and Moderate Ductility in an Al-Cu Alloy

Hockauf

Meyer

Krüger

2008

MSF

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Abstract. The effect of equal-channel angular extrusion (ECAE) on mechanical properties of an AA2017 produced by powder metallurgy is investigated. Special attention is given to the influence of heat treatment, processing temperature and backpressure on the workability for achieving high strength and moderate ductility. This is of special interest, since it is often reported that Al-Cu alloys have low ductility and therefore are prone to cracking during severe plastic deformation. It is shown that ECAE at high temperatures (>220°C) does not necessitate backpressure to ensure homogeneous deformation but leads to a significant sacrifice in strength due to in-situ precipitation. Thus, most of the extrusions are done at considerably low temperatures. Performing room temperature-extrusion is most effective in achieving high strengths but also requires high backpressures. Due to severe strain hardening during processing, the strength increase is combined with a reduction in ductility. Recently it was reported that a post-ECAE aging of pre-ECAE solution treated material is effective in enhancing the ductility of aluminium alloys. This approach was successfully transferred to the current alloy. A high-temperature, short-time aging after only one extrusion, for example, doubles the failure strain to a value of ~13%. Compared to the naturally aged condition with coarse grains that serves as reference (T4), an increase of 15 % in yield stress (YS) was obtained while retaining the ultimate tensile stress (UTS). Another effective approach is the combination of a pre-ECAE solution treatment with subsequent under-aging prior to ECAE. It is shown that performing ECAE at medium temperatures (160-180°C) enables a better workability and additionally gives higher strengths and better ductility compared to the processing in the water quenched condition. A remarkable YS of 530 MPa and an UTS of 580 MPa combined with a moderate failure strain of 11.6 % were achieved.

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“…Thus, the deformation at cryogenic temperature would require less plastic deformation for achieving ultrafine grains than other SPD processes at ambient or elevated temperatures. [11][12][13][14][15][16][17] Thus, it is anticipated that the large stored energy accumulated during the deformation at cryogenic temperature would lead to the larger driving force for the occurrence of dynamic recovery and, then, possibly reduce the required number of cycles in an ARB process to achieve ultrafine grains and high strength. Accordingly, the combination of cryogenic rolling with warm rolling, whose temperature range is similar to that of an ARB process, would become a good candidate for the formation of ultrafine grains with the less amount of the required deformation.…”

Section: Introductionmentioning

confidence: 99%

The Evolution of Microstructure and Mechanical Properties of a 5052 Aluminium Alloy by the Application of Cryogenic Rolling and Warm Rolling

2009

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The microstructural evolution and the corresponding mechanical properties of a 5052 Al alloy processed by cryogenic rolling followed by warm rolling were investigated. The application of cryogenic rolling combined with warm rolling at 448 K showed a significant improvement of tensile strength up to 452 MPa. The kinetics and the microstructural evolution occurred during warm rolling were investigated using differential scanning calorimeter and transmission electron microscope. This notable increase of tensile strength was achieved by the formation of fine precipitates during warm rolling. It was found that the cryogenic rolling combined with warm rolling would be effective in improving mechanical properties.

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Optimizing the strength and ductility of fine structured 2024 Al alloy by nano-precipitation

Cited by 453 publications

References 40 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

Combining Equal-Channel Angular Extrusion (ECAE) and Heat Treatment for Achieving High Strength and Moderate Ductility in an Al-Cu Alloy

The Evolution of Microstructure and Mechanical Properties of a 5052 Aluminium Alloy by the Application of Cryogenic Rolling and Warm Rolling

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