Condensed dislocation structures in polycrystalline aluminium fatigued at 77K

Charsley, P.; Harris, L. J.

doi:10.1016/0036-9748(87)90225-0

Cited by 24 publications

(15 citation statements)

References 7 publications

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“…28) In contrast, single-crystalline and CG Al show initial hardening, softening and secondary hardening 3234) with the formation of characteristic dislocation structure such as vein, 35,36) wall, 35,36) labyrinth 32,35,37) and cell 28,34) structures. Although the cyclic deformation behavior of UFG Al is worth investigating more in detail, most reports were on commercially pure Al or on Al alloys.…”

Section: )mentioning

confidence: 99%

“…These walls are considered to form layers, just like the labyrinth walls. 32,35,37) The average channel width between adjacent walls was about 350 nm (¾ pl = 1 © 10 ¹3 ) and about 330 nm (¾ pl = 5 © 10 ¹3 ). The absence of contrast variation among the channels indicates that the walls are made of edge dislocation dipoles.…”

Section: Microstructural Observationmentioning

confidence: 99%

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Stability of Fatigued Dislocation Wall Structure in Coarse-Grained and Ultrafine-Grained Aluminum against Monotonic Tensile Deformation

et al. 2013

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Coarse-grained (CG) and ultrafine-grained (UFG) pure aluminum samples fabricated by equal channel angular pressing (ECAP) were cyclically deformed at 77 K under constant plastic strain amplitude. Monotonic tensile tests were performed at 300 and 77 K soon after the fatigue tests. In spite of the increase in the tensile strength of fatigued CG Al, tensile ductility decreased remarkably in comparison to that of as-annealed CG Al. On the other hand, the ultimate tensile strength (UTS) and tensile ductility of UFG Al were much higher at 77 K than those at 300 K. Furthermore, UFG Al at 77 K maintained high UTS and high tensile ductility even after fatigue tests. Microstructural observation has revealed that dislocation wall structure formed in fatigued CG Al persists after the monotonic tensile tests. However, dislocation wall structure formed in fatigued UFG Al disappeared during early stages of monotonic tensile tests at both 300 and 77 K. These results indicate that the dislocation wall structure in UFG Al is unstable against succeeding monotonic tensile deformation.

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Section: )mentioning

confidence: 99%

Section: Microstructural Observationmentioning

confidence: 99%

Stability of Fatigued Dislocation Wall Structure in Coarse-Grained and Ultrafine-Grained Aluminum against Monotonic Tensile Deformation

et al. 2013

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“…7 shows that the fraction is nearly 60% when fatigued at 83 K. Average wall-to-wall spacing is about 300 nm and this value is much less than the frequently observed values between 1 to 4 mm in single-crystalline and coarse-grained Al. [13][14][15][16] As shown in Figs. 6(b) and (c), the dislocation walls appear to align parallel to the {1 0 0} plane just like those formed in single-crystalline and coarse-grained Al.…”

Section: Microstructural Observationmentioning

confidence: 99%

“…6(b) and (c), the dislocation walls appear to align parallel to the {1 0 0} plane just like those formed in single-crystalline and coarse-grained Al. [13][14][15][16][17] It is known that the multiple slip is responsible for the formation of the {100} walls and labyrinth structure in fcc metals. 15,18) It is very probable that such multiple slip (or the interaction between different slip systems) occurs very frequently in highly constrained grains of UFG materials.…”

Section: Microstructural Observationmentioning

confidence: 99%

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Low-Cycle Fatigue of Ultrafine-Grained Aluminum at Low Temperatures

et al. 2011

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Ultrafine-grained (UFG) Al of 99:98$99:99% purity was fabricated by equal channel angular pressing. Fully reversed tensioncompression low-cycle fatigue tests were carried out under plastic strain control at various temperatures between 83 K and 300 K. At 300 K, UFG Al showed rapid cyclic softening. As test temperature decreased, cyclic softening became less significant and at 83 K, UFG Al showed cyclic hardening till saturation. Formation of shear bands and development of dislocation structure were the characteristic features of fatigued specimens. As test temperature decreased, the area fraction of shear bands on specimen surface decreased and at 83 K, shear bands could not be observed. In addition, local grain coarsening occurred except at 83 K. Formation of dislocation cell and wall structures became more frequent at lower temperatures and well-developed dislocation walls were formed in grains as small as 1.5 mm in size at 83 K.

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Cyclic Hardening and Softening of [001] Al Single Crystals

Videm¹,

Ryum²

1989

Advances in Fatigue Science and Technology

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Condensed dislocation structures in polycrystalline aluminium fatigued at 77K

Cited by 24 publications

References 7 publications

Stability of Fatigued Dislocation Wall Structure in Coarse-Grained and Ultrafine-Grained Aluminum against Monotonic Tensile Deformation

Stability of Fatigued Dislocation Wall Structure in Coarse-Grained and Ultrafine-Grained Aluminum against Monotonic Tensile Deformation

Low-Cycle Fatigue of Ultrafine-Grained Aluminum at Low Temperatures

Cyclic Hardening and Softening of [001] Al Single Crystals

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