Characterization of Deformation Microstructures in Commercial Purity Aluminium

Sæter, Jan Anders; Nes, E.

doi:10.4028/www.scientific.net/msf.217-222.447

Cited by 3 publications

(2 citation statements)

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“…[20,23,26,27] In TEM, all SGBs can thus, to their spacing (s w ) or link length. [99,101,108] These be observed, and both and the dislocation spacing (s w ) concepts have given support to Blum's composite model of and arrangement in SGBs can be observed.…”

Section: Dislocation Substructuresupporting

confidence: 50%

“…[52,53] There are similarities of cold and hot working; the cells Scanning electron microscopy with back-scattered electrons are usually elongated and much smaller than the subgrains (SEM-EBS) reveals the subgrains which correspond well yet, at high levels in stage III or IV, often become considerwith POM and are usually larger than in TEM; misorientaably polygonized. [25,26,[101][102][103][104][105][106][107][108] The flow stress has been tions ( ) can be measured, but not those of the smallest related to bowing out of dislocations from the walls and, subgrains with low levels. [20,23,26,27] In TEM, all SGBs can thus, to their spacing (s w ) or link length.…”

Section: Dislocation Substructurementioning

confidence: 99%

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Elevated-temperature deformation at forming rates of 10−2 to 102 s−1

McQueen

2002

Metall Mater Trans A

123

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In the hot working at constant strain rate () of Al and ␣ Fe alloys at 0.5 to 0.9 T M (absolute melting temperature), steady-state deformation is achieved in similarity to creep, which is usually at constant stress. After an initial strain-hardening transient, the flow stress becomes constant in association with a substructure which remains equiaxed and constant in the spacing of sub-boundaries and of dislocations in both walls and subgrains. All these spacings become larger at higher temperature (T ) and lower values as well as with lower stress, being fully consistent with the relationships established in creep. Because hot working can proceed to a much higher true strain in torsion (ϳ100) and compression (ϳ2) as well as in extrusion (ϳ20) and rolling (ϳ5), it is possible to confirm that grains continue to elongate while the subgrains within them remain equiaxed and constant in size. When the thickness of grains reaches about 2 subgrain diameters (d s ), the grain boundaries with serrations (ϳd s ) begin to impinge and the grains pinch off, becoming somewhat indistinguishable from the subgrains; this has been called geometric dynamic recrystallization (DRX). In polycrystals as at 20 ЊC, deformation bands form and rotate during hot working according to the Taylor theory, developing textures very similar to those in cold working. In metals of lower dynamic recoverability such as Cu, Ni, and ␥ Fe, new grains nucleate and grow (discontinuous DRX), leading to a steady state related to frequently renewed equiaxed grains, containing an equiaxed substructure that develops to a constant character and defines the flow stress.

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Section: Dislocation Substructuresupporting

confidence: 50%

Section: Dislocation Substructurementioning

confidence: 99%

Elevated-temperature deformation at forming rates of 10−2 to 102 s−1

McQueen

2002

Metall Mater Trans A

123

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Dynamic recovery: sufficient mechanism in the hot deformation of Al (<99.99)

McQueen¹,

Blum²

2000

Materials Science and Engineering: A

173

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Developing stable fine–grain microstructures by large strain deformation

Humphreys

Prangnell

Bowen

et al. 1999

Philosophical Transactions of the Royal Society of London. Seri

363

204

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Methods of deforming metals to large strains are reviewed and the process of equal channel angular extrusion is analysed in detail. The development of microstructure during large strain deformation is discussed, and it is concluded that the main criterion for the formation of a sub-micron grain structure is the generation of a sufficiently large fraction (greater than 0.7) of high-angle grain boundary during the deformation process. For aluminium alloys, it is found that a low-temperature anneal is required to convert the deformed microstructure into an equiaxed grain structure. The material, microstructural and processing factors that influence the formation of such fine-grain microstructures are discussed, and the stability of these microstructures at elevated temperatures is considered.

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Characterization of Deformation Microstructures in Commercial Purity Aluminium

Cited by 3 publications

References 0 publications

Elevated-temperature deformation at forming rates of 10−2 to 102 s−1

Elevated-temperature deformation at forming rates of 10−2 to 102 s−1

Dynamic recovery: sufficient mechanism in the hot deformation of Al (<99.99)

Developing stable fine–grain microstructures by large strain deformation

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