M.Yu.Gutkin*, I.A.Ovid'ko* and C.S.Pande**
*Institute of Problems of Mechanical Engineering,
Russian Academy of Sciences,
St.Petersburg, Russia
**Naval Research Laboratory, Washington, DC, USA
Abstract
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We provide an overview of theoretical models of
plastic deformation processes in nanocrystalline materials. The
special attention is paid to the abnormal Hall-Petch relationship
which manifests itself as the softening of nanocrystalline
materials with reducing the mean grain size. Theoretical models
are considered which describe the deformation behavior of
nanocrystalline materials as two-phase composites with grain
interiors and boundaries playing the role as component phases.
Also, physical mechanisms (lattice dislocation motion, grain
boundary sliding, diffusion plasticity mechanisms) of plastic flow
in nanocrystalline materials are analysed with emphasis on
transitions from one to another deformation mechanism with
reduction of grain size. The effect of a distribution of grain
size on the abnormal Hall-Petch relationship in nanocrystalline
materials is considered.
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full paper (pdf, 224 Kb)