Precipitation strengthening of aluminum alloys by room-temperature cyclic plasticity

Sun, Weifeng; Zhu, Yuman; Marceau, Ross K. W.; Wang, Lingyu; Zhang, Qi; Gao, Xiang; Hutchinson, Christopher

doi:10.1126/science.aav7086

Cited by 381 publications

(109 citation statements)

References 18 publications

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“…The cell-structure could in turn create a beneficial precipitate distribution during artificial ageing, causing the precipitates to grow in a somewhat cell-like structure. The strengthening effect by cyclic plasticity was described by Sun et al [33], where cyclic deformation during natural ageing significantly enhances the strength of three aluminium alloys. They demonstrated that dislocation loops were present and atomic clusters were heterogeneously distributed throughout the material.…”

Section: Discussionmentioning

confidence: 86%

“…It is likely that we are observing a somewhat similar effect in this study, where clustering is partly heterogeneous and dislocations become mobile during elastic straining. In the material which was subjected to cyclic deformation the precipitation free zones were absent, giving an additional positive effect on strength [33]. Strain accumulation is a steady process which tends to localise [34], and in many cases this occurs at the precipitation free zone (PFZ).…”

Section: Discussionmentioning

confidence: 99%

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The Effect of Elastic Strain and Small Plastic Deformation on Tensile Strength of a Lean Al–Mg–Si Alloy

Mørtsell

Westermann

Marioara

et al. 2019

Metals

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Al–Mg–Si alloys are usually formed into their final shape by rolling or extrusion. After extrusion, the aluminium profiles are usually straightened, causing the material to be subjected to a small plastic deformation. This study demonstrates the positive effect on strength that can be obtained from such small deformation levels or from only elastically straining the material. Elastic straining of a lean Al–Mg–Si alloy, when performed immediately after solution heat treatment, enhances the material yield strength after artificial ageing to T6. Transmission electron microscopy shows that this effect can be attributed to a higher number density and finer dispersion of the age-hardening precipitate needles. Furthermore, introducing a small plastic deformation of 1% after solution heat treatment results in a comparable strength increase to elastically straining the material. In this case, however, the strength increase is due to the increased dislocation density, which compensates for a lower density of precipitate needles. Finally, by combining plastic deformation with a succeeding elastic strain, we demonstrate how elastic strain can cause an on-set of dislocation cell formation in this material.

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Section: Discussionmentioning

confidence: 86%

Section: Discussionmentioning

confidence: 99%

The Effect of Elastic Strain and Small Plastic Deformation on Tensile Strength of a Lean Al–Mg–Si Alloy

Mørtsell

Westermann

Marioara

et al. 2019

Metals

View full text Add to dashboard Cite

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“…Other systems where coherent precipitates form first, whether in metallic alloys 7 or even minerals 3 are numerous and may well exhibit TDN and are worth exploring. These mechanisms are also likely to take place in real-life situations such as fatigue, creep, irradiation 40 and novel processing treatments 41 of engineering alloy components, or in the far-fromequilibrium conditions associated with 3D-printing 42 . Finally, our approach may offer a strategy for alloy design based on injection of vacancies, thus avoiding the reliance on costly or environmentally detrimental microalloying additions 43 .…”

Section: Discussionmentioning

confidence: 99%

Transforming solid-state precipitates via excess vacancies

Bourgeois

Zhang

et al. 2020

Nat Commun

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Many phase transformations associated with solid-state precipitation look structurally simple, yet, inexplicably, take place with great difficulty. A classic case of difficult phase transformations is the nucleation of strengthening precipitates in high-strength lightweight aluminium alloys. Here, using a combination of atomic-scale imaging, simulations and classical nucleation theory calculations, we investigate the nucleation of the strengthening phase θ′ onto a template structure in the aluminium-copper alloy system. We show that this transformation can be promoted in samples exhibiting at least one nanoscale dimension, with extremely high nucleation rates for the strengthening phase as well as for an unexpected phase. This template-directed solid-state nucleation pathway is enabled by the large influx of surface vacancies that results from heating a nanoscale solid. Template-directed nucleation is replicated in a bulk alloy as well as under electron irradiation, implying that this difficult transformation can be facilitated under the general condition of sustained excess vacancy concentrations.

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“…Wrought aluminum alloys, as a class of pervasive structural materials, are broadly used in aerospace and automobile sectors due to their low density, high strength to weight ratio and natural availability [1][2][3][4]. Currently, most parts made of wrought aluminum alloys are fabricated by plastic forming and precision machining [5,6].…”

Section: Introductionmentioning

confidence: 99%

Current Progress in Rheoforming of Wrought Aluminum Alloys: A Review

Gan

et al. 2020

Metals

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Semi-solid processing (SSP), including rheoforming and thixoforming, offers a promising opportunity to manufacture net-shaped parts with complex structure and excellent mechanical properties. Owing to its low cost and short process, rheoforming has been the subject of extensive study over the last two decades. The interest in the rheoforming of wrought aluminum alloys is progressively growing among both the research and industrial communities. This review starts with reviewing the recent efforts and advances on preparation of semi-solid slurry of wrought Al alloys, followed by discussing the correlation between microstructure and performance of these alloys. Finally, special attention is paid in the industrial application and the future trends of rheoforming of wrought aluminum alloys.

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Precipitation strengthening of aluminum alloys by room-temperature cyclic plasticity

Cited by 381 publications

References 18 publications

The Effect of Elastic Strain and Small Plastic Deformation on Tensile Strength of a Lean Al–Mg–Si Alloy

The Effect of Elastic Strain and Small Plastic Deformation on Tensile Strength of a Lean Al–Mg–Si Alloy

Transforming solid-state precipitates via excess vacancies

Current Progress in Rheoforming of Wrought Aluminum Alloys: A Review

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