Orientation-dependent grain growth in a bulk nanocrystalline alloy during the uniaxial compressive deformation

Fan, G. J.; Wang, Y. D.; Fu, Liangjie; Choo, Hahn; Liaw, Peter K.; Ren, Yang; Browning, Nigel D.

doi:10.1063/1.2200589

Cited by 70 publications

(37 citation statements)

References 22 publications

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“…The grain sizes were systematically increased by plastic deformation using a technique called highpressure torsion (HPT). Plastic deformation is known to induce grain growth in nc materials [60,[74][75][76][77][78][79][80]. The average grain size increased to 115 nm after 30 HPT revolutions, making it possible to study statistical changes in twin density during deformation over a wide nano-grain size range from 10 nm to over 100 nm.…”

Section: Experimental Observations On the Grain Size Effectmentioning

confidence: 99%

Grain size effect on deformation twinning and detwinning

et al. 2013

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This article systematically overviews the grain size effect on deformation twinning and detwinning in face-centered cubic (fcc) metals. With decreasing grain size, coarse-grained fcc metals become more difficult to deform by twinning, whereas nanocrystalline (nc) fcc metals first become easier to deform by twinning and then become more difficult, exhibiting an optimum grain size for twinning. The transition in twinning behavior from coarse-grained to nc fcc metals is caused by the change in deformation mechanisms. An analytical model based on observed deformation physics in nc metals, i.e., grain boundary emission of dislocations, provides an explanation of the observed optimum grain size for twinning in nc fcc metals. The detwinning process is caused by the interaction between dislocations and twin boundaries. Under a certain deformation condition, there exists a grain size range where the twinning process dominates over the detwinning process to produce the highest density of twins.

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Section: Experimental Observations On the Grain Size Effectmentioning

confidence: 99%

Grain size effect on deformation twinning and detwinning

et al. 2013

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“…Away from the strain localization, grains remain equiaxed and a similar size as the starting structure. Mechanically-induced grain growth has been observed in a number of nanocrystalline metals such as Al, 10,41 Ni, 42,43 and Cu, 9 as well as alloys such as Ni-Fe, 44,45 Ni-W, 46,47 and Co-P. 48 This grain growth can be caused by a combination of grain boundary migration and coalescence due to grain rotation, and has been shown to be driven by high shear stress. 49 While small areas of high shear strain are observed at ε = 5.0%, a path of high strain that spans the sample becomes clear at approximately ε = 5.4%, after a major stress drop in the stress-strain curve presents in Fig.…”

Section: A Atomic-level Observations Of Localization Processesmentioning

confidence: 99%

Strain localization in a nanocrystalline metal: Atomic mechanisms and the effect of testing conditions

Rupert¹

2013

Journal of Applied Physics

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Abstract:Molecular dynamics simulations are used to investigate strain localization in a model nanocrystalline metal. The atomic mechanisms of such catastrophic failure are first studied for two grain sizes of interest. Detailed analysis shows that the formation of a strain path across the sample width is crucial, and can be achieved entirely through grain boundary deformation or through a combination of grain boundary sliding and grain boundary dislocation emission.Pronounced mechanically-induced grain growth is also found within the strain localization region. The effects of testing conditions on strain localization are also highlighted, to understand the conditions that promote shear banding and compare these observations to metallic glass behavior. We observed that, while strain localization occurs at low temperatures and slow strain rates, a shift to more uniform plastic flow is observed when either strain rate or temperature is increased. We also explore how external sample dimensions influence strain localization, but find no size effect for the grain sizes and samples sizes studied here.2

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“…There are two explanations for the coarse grains that appeared in the ultrafine-structured CTD sample: in situ grain growth during deformations [16,17] and recrystallization. [18] The former (grain growth) is attributed to non-uniform grain boundary mobility of ultrafine materials, which leads to sub-grain growth and local inhomogeneous distribution of stress, and to subsequent grain rotation for sub-grain agglomeration.…”

Section: Resultsmentioning

confidence: 99%

Bi-modal Structure of Copper via Room-Temperature Partial Recrystallization After Cryogenic Dynamic Compression

Ahn

Lee

Kang

et al. 2016

Metall Mater Trans A

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PURE copper was compressed at high strain rates (over~3 9 10 3 s À1 ) under liquid nitrogen. This deformation resulted in bi-modal microstructures of ultrafine grains and abnormally grown micro grains, and in greater hardness (by~30 Hv) than room-temperature, dynamically deformed copper. This bi-modal microstructure is attributable to partial recrystallization at room temperature, activated by high-energy states and by twins generated at high ZenerHollomon parameter conditions. This result demonstrates a new approach for producing bi-modally structured materials.

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Orientation-dependent grain growth in a bulk nanocrystalline alloy during the uniaxial compressive deformation

Cited by 70 publications

References 22 publications

Grain size effect on deformation twinning and detwinning

Grain size effect on deformation twinning and detwinning

Strain localization in a nanocrystalline metal: Atomic mechanisms and the effect of testing conditions

Bi-modal Structure of Copper via Room-Temperature Partial Recrystallization After Cryogenic Dynamic Compression

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