Deformation Induced Internal Friction Peaks in Nanocrystalline Nickel

Li, Pingyun; Zhang, Xiyan; Ni, Haitao; Cao, Zhenhua; Meng, Xiangkang

doi:10.1088/0256-307x/29/2/026201

Cited by 1 publication

(1 citation statement)

References 23 publications

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“…However, as suggested by molecular dynamics (MD) simulations. [1][2][3][4] and experiments, [5][6][7] such dislocation activity is no longer possible in metals when the grain size is reduced to nanometer level and is replaced by the emission of dislocations from grain boundary (GB) sources. The emitted dislocations will propagate across the grains and eventually be absorbed in the opposite GBs.…”

Section: Introductionmentioning

confidence: 99%

Dislocation-mediated creep process in nanocrystalline Cu

Jun-Wei¹,

Sun²,

Jiang³

et al. 2013

Chinese Phys. B

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Nanocrystalline Cu with average grain sizes ranging from ∼ 24.4 to 131.3 nm were prepared by the electric brushplating technique. Nanoindentation tests were performed within a wide strain rate range, and the creep process of nanocrystalline Cu during the holding period and its relationship to dislocation and twin structures were examined. It was demonstrated that creep strain and creep strain rate are considerably significant for smaller grain sizes and higher loading strain rates, and are far higher than those predicted by the models of Cobble creep and grain boundary sliding. The analysis based on the calculations and experiments reveals that the significant creep deformation arises from the rapid absorption of high density dislocations stored in the loading regime. Our experiments imply that stored dislocations during loading are highly unstable and dislocation activity can proceed and lead to significant post-loading plasticity.

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