An evaluation of the flow behavior during high strain rate superplasticity in an Al−Mg−Sc alloy

Komura, Shogo; Horita, Zenji; Furukawa, Mutsuhisa; Nemoto, Minoru; Langdon, Terence G.

doi:10.1007/s11661-001-1006-9

Cited by 50 publications

(48 citation statements)

References 46 publications

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“…Inspection of the curves reveals that a peak strength is achieved rapidly at an engineering strain of~5 %, and then the stress drops continuously with increasing engineering strain. The stress-strain curves with a continuous stress-drop is similar to other superplastic materials, for instance, ultrafine-grained Al-Mg-Sc alloy processed via equal-channel-angular pressing, [17] and nanostructured Pb62Sn processed by high pressure torsion, [18] but is substantially different from stress-strain curves in nanostructured Ti-6Al-4V alloy, 1420 Al and Ni 3 Al intermetallic processed by high pressure torsion.…”

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confidence: 57%

High‐strain‐rate Superplasticity in a Nanostructured Al‐Mg Alloy

Han¹,

Lavernia²

2005

Adv Eng Mater

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In this work, the authors report high‐strain‐rate superplasticity in a nanostructured Al‐7.5%Mg alloy with a mean grain size of 90 nm processed via consolidation of cryomilled Al‐Mg powders. Tensile ductility with an elongation of 291% was observed at a strain rate of 10‐1 s‐1 and at a temperature of 573 K. Noteworthy is the fact that the microstructure is essentially stable during testing at 573 K. Grain boundary sliding is suggested to be the dominant deformation mechanism in the superplastic deformation of the nanostructured Al‐Mg alloy.

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confidence: 57%

High‐strain‐rate Superplasticity in a Nanostructured Al‐Mg Alloy

Han¹,

Lavernia²

2005

Adv Eng Mater

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“…Figure 4 shows an example of the experimental results achieved after ECAP and subsequent testing in tension at temperatures from 573 to 723 K. [26] [20], Al-2024 alloy [21] and Al-7034 alloy. Fig.…”

Section: Experimental Results With Aluminum-basedmentioning

confidence: 99%

“…4. Elongation to failure versus strain rate for an Al-3 % Mg-0.2 % Sc alloy after ECAP and after cold rolling [26].…”

Section: Experimental Results With Aluminum-basedmentioning

confidence: 99%

Achieving a Superplastic Forming Capability through Severe Plastic Deformation

Furukawa

Horita

et al. 2003

Adv Eng Mater

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Processing by severe plastic deformation (SPD) leads to very significant grain refinement in metallic alloys. Furthermore, if these ultrafine grains are reasonably stable at elevated temperatures, there is a potential for achieving high tensile ductilities, and superplastic elongations, in alloys that are generally not superplastic. In addition, the production of ultrafine grains leads to the occurrence of superplastic flow at strain rates that are significantly faster than in conventional alloys so that processing by SPD introduces the possibility of using these alloys for the rapid fabrication of complex parts through superplastic forming operations. This paper examines the development of superplasticity in various aluminum alloys processed by equal‐channel angular pressing (ECAP).

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“…It was reported that stress mine the strain rate sensitivity. While a single specimen was relief in the as-ECAP alloy with extremely high localized pulled to failure in the monotonic tests, the initial crosshead stresses by severe plastic deformation can easily occur by speed was changed abruptly to the predetermined one in the substructure rearrangement even at relatively low annealing strain rate change tests after the maximum true stress was temperatures: [14,15] for instance, note the rapid loss of hardconfirmed during deformation at the initial crosshead ness at 323 K, as shown in Figure 1. Above 573 K, it speed.…”

Section: Introductionmentioning

confidence: 99%

Low-temperature superplastic behavior of a submicrometer-grained 5083 Al alloy fabricated by severe plastic deformation

Park

Hwang

Chang

et al. 2002

Metall Mater Trans A

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A submicrometer-grained structure was introduced in a commercial 5083 Al alloy by imposing an effective strain of ϳ8 through equal channel angular pressing. In order to examine the low-temperature superplastic behavior, the as-equal channel angular pressed (as-ECAP) samples were tensile tested in the strain rate range of 10 Ϫ5 to 10 Ϫ2 s Ϫ1 at temperatures of 498 to 548 K corresponding to 0.58 to 0.65 T m , where T m is the incipient melting point. The mechanical data of the alloy at 498 and 548 K exhibited a sigmoidal behavior in a double logarithmic plot of the maximum true stress vs true strain rate. The strain rate sensitivity was 0.1 to 0.2 in the low-and high-strain rate regions and 0.4 in the intermediate-strain rate region, indicating the potential for superplasticity. At 523 K, instead of the sigmoidal behavior, a strain rate sensitivity of 0.4 was maintained to low strain rates. A maximum elongation of 315 pct was obtained at 548 K and 5 ϫ 10 Ϫ4 s Ϫ1 . The activation energy for deformation in the intermediate-strain rate region was estimated as 63 kJ/mol. Low-temperature superplasticity of the ultrafine grained 5083 Al alloy was attributed to grain boundary sliding that is rate-controlled by grain boundary diffusion, with a low activation energy associated with nonequilibrium grain boundaries. Cavity stringers parallel to the tensile axis were developed during deformation, and the failure occurred in a quasi-brittle manner with moderately diffusive necking.

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An evaluation of the flow behavior during high strain rate superplasticity in an Al−Mg−Sc alloy

Cited by 50 publications

References 46 publications

High‐strain‐rate Superplasticity in a Nanostructured Al‐Mg Alloy

High‐strain‐rate Superplasticity in a Nanostructured Al‐Mg Alloy

Achieving a Superplastic Forming Capability through Severe Plastic Deformation

Low-temperature superplastic behavior of a submicrometer-grained 5083 Al alloy fabricated by severe plastic deformation

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