Influence of scandium and zirconium on grain stability and superplastic ductilities in ultrafine-grained Al–Mg alloys

Lee, S; Utsunomiya, Atsushi; Akamatsu, Hiroki; Neishi, Koji; Furukawa, Mutsuhisa; Horita, Zenji; Langdon, Terence G.

doi:10.1016/s1359-6454(01)00368-8

Cited by 334 publications

(175 citation statements)

References 31 publications

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“…After tensile testing at 673 K (400°C) at 10 À2 s À1 of this alloy in the ECAP condition, secondary Al 3 (Sc,Zr) precipitates were about 5 nm in size. Works of Jones et al [34] and Lee et al [35] show the thermal resistance of Al 3 Sc or Al 3 (Sc,Zr) toward coarsening and dissolution as well. Hence, these precipitates provide sufficient pinning force on the grain boundaries of refined microstructure and retard the grain growth.…”

Section: A Grain Refinement and The Role Of Al 3 (Sc Zr) Dispersoidsmentioning

confidence: 96%

“…One hour annealing at 773 K (500°C) led to a precipitate size of 20 nm in this alloy. Lee et al [35] reported a precipitate size of 25 to 60 nm after a solution treatment of Al-Mg-Sc-Zr alloy for 1 hour at 883 K (610°C). After tensile testing at 673 K (400°C) at 10 À2 s À1 of this alloy in the ECAP condition, secondary Al 3 (Sc,Zr) precipitates were about 5 nm in size.…”

Section: A Grain Refinement and The Role Of Al 3 (Sc Zr) Dispersoidsmentioning

confidence: 99%

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Ultrafine-Grained Al-Mg-Sc Alloy via Friction-Stir Processing

Kumar

Mishra

2012

Metall Mater Trans A

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Friction-stir processing (FSP) of twin-roll cast (TRC) Al-Mg-Sc alloy resulted into ultrafinegrained microstructure. The alloy was processed in as-received and aged (563 K [290°C], 22 hours) conditions and at three different tool rotation rates: 800, 400, and 325 rpm. The microstructural features were characterized using electron backscattered diffraction (EBSD), scanning electron microscopy (SEM), and transmission electron microscopy (TEM). The grain size varied from 0.89 lm to 0.39 lm depending on the processing and initial thermo-mechanical conditions of the alloy. The TRC alloy processed at 325 rpm in aged condition had all the grains less than 1 lm, and 95 pct of grains had high-angle grain boundaries (HAGBs). In all the cases, the fraction of HAGBs were more than 80 pct. The variation of misorientation angle distribution was similar to the theoretical MacKenzie distribution for cubic crystal materials. Grain size analysis at different sections and locations on the transverse section of the dynamically recrystallized zone showed a homogeneous and equiaxed microstructure. The average dispersoid (Al 3 (Sc,Zr)) size was~8.0 nm in diameter obtained using high-resolution TEM. Grain size reduction was observed with increase in Zener-Hollomon parameter. It was shown that under the current microstructural and deformation conditions, dynamic recrystallization via particlestimulated nucleation might not be possible during FSP.

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Section: A Grain Refinement and The Role Of Al 3 (Sc Zr) Dispersoidsmentioning

confidence: 96%

Section: A Grain Refinement and The Role Of Al 3 (Sc Zr) Dispersoidsmentioning

confidence: 99%

Ultrafine-Grained Al-Mg-Sc Alloy via Friction-Stir Processing

Kumar

Mishra

2012

Metall Mater Trans A

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“…1a. Effect of grain size on superplastic strain rate in Al alloys; [7] datum points for ECAP [11][12][13][14][15][16][17][18][19][20] are in black and for HPT [21][22][23][24][25][26][27][28][29] in red; the encircling ovals are in blue for ECAP and pink for HPT and the solid line corresponds to eq. (2) in the text.…”

Section: Figure Captionsmentioning

confidence: 99%

“…[7,10] The experimental results shown in Fig. 1[a] are taken from various reports for Al alloys, [11][12][13][14][15][16][17][18][19][20][21][22][23][24][25][26][27][28][29] and in Fig. 1 [b] there are similar sets of data for a range of Mg alloys [30][31][32][33][34][35][36][37][38][39][40][41][42][43][44][45][46][47][48][49] where the upper solid lines in Figs 1[a] and [b] show the predicted normalized strain rates derived using eq.…”

Section: Introductionmentioning

confidence: 99%

The Strength–Grain Size Relationship in Ultrafine-Grained Metals

Balasubramanian

Langdon

2016

Metall Mater Trans A

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Metals processed by severe plastic deformation [SPD] techniques, such as equal-channel angular pressing [ECAP] and high-pressure torsion [HPT], generally have submicrometer grain sizes. Consequently, they exhibit high strength as expected on the basis of the HallPetch [H-P] relationship. Examples of this behavior are discussed using data on Ti, Al-Mg 1 and Ni. These materials typically have grain size above ~50 nm where softening is not expected. An increase in strength is usually accompanied by a decrease in ductility. High strength and ductility can be achieved simultaneously by imposing high strains to give both ultrafine grain sizes and a high fraction of high-angle grain boundaries. An example is presented for a cast Al-7% Si alloy processed by HPT. In some cases, SPD may produce a fine grain size but also lead to a weakening due to microstructural changes as in ECAP of an Al-7034 alloy and HPT of Zn-22% Al. In SPD-processed materials, grain boundary segregation and nanostructural features are present which may lead to higher strengths than those predicted by the H-P relationship in some alloys having nano grain sizes.

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“…In severe plastic deformation (SPD), conventional microstructures materials are changed to submicron or nanoscaled ones [11][12][13]. Equal channel angular pressing (ECAP) is one of the most effective processing methods among the group of SPD methods [14,15].…”

Section: Introductionmentioning

confidence: 99%

Microembossing of ultrafine grained Al: microstructural analysis and finite element modelling

Qiao

Bah

Zhang

et al. 2010

J. Micromech. Microeng.

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Ultra-fine-grained (UFG) Al-1050 processed by equal channel angular pressing and UFG Al-Mg-Cu-Mn processed by high-pressure torsion (HPT) were embossed at both room temperature and 300 • C, with the aim of producing micro-channels. The behaviour of Al alloys during the embossing process was analysed using finite element modelling. The cold embossing of both Al alloys is characterized by a partial pattern transfer, a large embossing force, channels with oblique sidewalls and a large failure rate of the mould. The hot embossing is characterized by straight channel sidewalls, fully transferred patterns and reduced loads which decrease the failure rate of the mould. Hot embossing of UFG Al-Mg-Cu-Mn produced by HPT shows a potential of fabrication of microelectromechanical system components with micro channels.

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Influence of scandium and zirconium on grain stability and superplastic ductilities in ultrafine-grained Al–Mg alloys

Cited by 334 publications

References 31 publications

Ultrafine-Grained Al-Mg-Sc Alloy via Friction-Stir Processing

Ultrafine-Grained Al-Mg-Sc Alloy via Friction-Stir Processing

The Strength–Grain Size Relationship in Ultrafine-Grained Metals

Microembossing of ultrafine grained Al: microstructural analysis and finite element modelling

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