Deformation behavior in nanocrystalline copper

Youngdahl, Carl J.; Weertman, J.; Hugo, Richard; Kung, H.

doi:10.1016/s1359-6462(01)00712-6

Cited by 135 publications

(57 citation statements)

References 11 publications

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“…This higher strength of the b-high sample-condition can also be attributed to the presence of twins as revealed by HRTEM analysis, shown earlier in Figure 8. Dense dispersion of twins is known to provide improved multifunctional characteristics to the material, from improved strength to enhanced ductility [34][35][36][37][38][39][40]. Initially, we were surprised to observe the presence of twins even amongst the rampant presence of dislocation structures in the moderately high SFE Cu, particularly at high temperature expected in the deformation zone.…”

Section: Discussionmentioning

confidence: 99%

“…Severe plastic deformation (SPD) in metallic systems is accompanied not only by grain refinement which endows it with strength [1][2][3][4], but also by generation and organization of high density of crystal defects. The energies stored in various configurations of these defects provide the driving force for most observed recovery and recrystallization phenomena [5][6][7][8][9].…”

Section: Introductionmentioning

confidence: 99%

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Effect of strain rate in severe plastic deformation on microstructure refinement and stored energies

Shekhar¹,

Cai²,

Basu³

et al. 2011

J. Mater. Res.

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The interplay of large strain and large strain-rate during high rate severe plastic deformation (HR-SPD) leads to dynamic temperature rise in situ that engenders a recovered microstructure whose characteristics is not just a function of the strain, but also of the strain-rate and the coupled temperature rise during the deformation. In this paper, we identify three classes of microstructures characterized by multi-stage recovery phenomena, that take place during the high strain-rate SPD of Cu. It is found that the first stage of this recovery is similar to the first stage of static recovery which is characterized mainly by annihilation of dislocations. Second stage starts around 360K and was characterized by dislocations getting arranged in tight cell boundaries and eventually into sub-grain. Recovery stages were found to be followed by a stage of grain growth and recrystallization when the temperature in the deformation zone approaches 480K.

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Section: Discussionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Effect of strain rate in severe plastic deformation on microstructure refinement and stored energies

Shekhar¹,

Cai²,

Basu³

et al. 2011

J. Mater. Res.

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“…Basic understanding of structure-property relationships is essential to elucidate the mechanisms responsible for the deformation of nanocrystalline metals. The technique of in situ straining of TEM foil specimens is effective to explore the deformation and grain-boundary structures of nanocrystalline materials [317,346,369]. TEM observation is focused within localized small areas of samples, hence the results may not be representative of the bulk behavior.…”

mentioning

confidence: 99%

“…No evidence of dislocation activity was detected during straining. Youngdahl et al [369] strained nanocrystalline IGC Cu foils in a TEM, and videotaped the experiments. The grain size distribution of the Cu sample was very broad, ranging from 2 to 500 nm, with the majority lying between 50 and 80 nm.…”

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confidence: 99%

Nanocrystalline materials and coatings

Tjong

Chen

2004

Materials Science and Engineering: R: Reports

842

345

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In recent years, near-nano (submicron) and nanostructured materials have attracted increasingly more attention from the materials community. Nanocrystalline materials are characterized by a microstructural length or grain size of up to about 100 nm. Materials having grain size of $0.1 to 0.3 mm are classified as submicron materials. Nanocrystalline materials exhibit various shapes or forms, and possess unique chemical, physical or mechanical properties. When the grain size is below a critical value ($10-20 nm), more than 50 vol.% of atoms is associated with grain boundaries or interfacial boundaries. In this respect, dislocation pile-ups cannot form, and the Hall-Petch relationship for conventional coarse-grained materials is no longer valid. Therefore, grain boundaries play a major role in the deformation of nanocrystalline materials. Nanocrystalline materials exhibit creep and super plasticity at lower temperatures than conventional micro-grained counterparts. Similarly, plastic deformation of nanocrystalline coatings is considered to be associated with grain boundary sliding assisted by grain boundary diffusion or rotation. In this review paper, current developments in fabrication, microstructure, physical and mechanical properties of nanocrystalline materials and coatings will be addressed. Particular attention is paid to the properties of transition metal nitride nanocrystalline films formed by ion beam assisted deposition process. #

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“…51,59,60) On the other hand, it has been pointed out that as a propagating dislocation traverses the grain towards the opposite boundary, its two ends may be pinned by GB impurities or ledges. 56,61,62) When such pinning occurs, the depinning process can be a rate-controlling step of the thermallyactivated deformation of UFG materials.…”

Section: Deformation Kinetics Of Ufg and Nc Materialsmentioning

confidence: 99%

Hall–Petch Relationship and Dislocation Model for Deformation of Ultrafine-Grained and Nanocrystalline Metals

Kato

2014

Mater. Trans.

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Models and theories to explain the HallPetch relationship are reviewed briefly. Then, a dislocation model to incorporate some characteristic mechanical properties of ultrafine-grained and nanocrystalline metals will be introduced and used to explain some experimental results. The model is based on the idea that dislocations emitted from grain boundaries and bow out into grain interiors during their propagation are responsible for plastic deformation and thermally-activated depinning process at grain boundaries is regarded to be rate controlling. Some implications of the model are discussed in the light of recent experimental results.

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Deformation behavior in nanocrystalline copper

Cited by 135 publications

References 11 publications

Effect of strain rate in severe plastic deformation on microstructure refinement and stored energies

Effect of strain rate in severe plastic deformation on microstructure refinement and stored energies

Nanocrystalline materials and coatings

Hall–Petch Relationship and Dislocation Model for Deformation of Ultrafine-Grained and Nanocrystalline Metals

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Deformation behavior in nanocrystalline copper

Cited by 135 publications

References 11 publications

Effect of strain rate in severe plastic deformation on microstructure refinement and stored energies

Effect of strain rate in severe plastic deformation on microstructure refinement and stored energies

Nanocrystalline materials and coatings

Hall&ndash;Petch Relationship and Dislocation Model for Deformation of Ultrafine-Grained and Nanocrystalline Metals

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Hall–Petch Relationship and Dislocation Model for Deformation of Ultrafine-Grained and Nanocrystalline Metals