Competing grain-boundary- and dislocation-mediated mechanisms in plastic strain recovery in nanocrystalline aluminum
نویسندگان
چکیده
منابع مشابه
Grain boundary-mediated plasticity in nanocrystalline nickel.
The plastic behavior of crystalline materials is mainly controlled by the nucleation and motion of lattice dislocations. We report in situ dynamic transmission electron microscope observations of nanocrystalline nickel films with an average grain size of about 10 nanometers, which show that grain boundary-mediated processes have become a prominent deformation mode. Additionally, trapped lattice...
متن کاملStress-assisted grain growth in nanocrystalline metals: Grain boundary mediated mechanisms and stabilization through alloying
The mechanisms of stress-assisted grain growth are explored using molecular dynamics simulations of nanoindentation in nanocrystalline Ni and Ni-1 at.% P as a function of grain size and deformation temperature. Grain coalescence is primarily confined to the high stress region beneath the simulated indentation zone in nanocrystalline Ni with a grain size of 3 nm. Grain orientation and atomic dis...
متن کاملGrain rotation mediated by grain boundary dislocations in nanocrystalline platinum
Grain rotation is a well-known phenomenon during high (homologous) temperature deformation and recrystallization of polycrystalline materials. In recent years, grain rotation has also been proposed as a plasticity mechanism at low temperatures (for example, room temperature for metals), especially for nanocrystalline grains with diameter d less than ~15 nm. Here, in tensile-loaded Pt thin films...
متن کاملOn plastic strain recovery in freestanding nanocrystalline metal thin films
In a recent article [J. Rajagopalan, J.H. Han, M.T.A. Saif, Science 315 (2007) 1831–1834], we have reported substantial (50–100%) plastic strain recovery in freestanding nanocrystalline metal films (grain size 50–65 nm) after unloading. The strain recovery was time dependent and thermally activated. Here we model the time evolution of this strain recovery in terms of a thermally activated dislo...
متن کاملComment on "Grain boundary-mediated plasticity in nanocrystalline nickel".
Nanograin rotation via grain boundary sliding has been predicted as an important deformation mode in nanocrystalline materials as grain sizes approach less than 10 nm (1–3). However, definite experimental evidence beyond molecular dynamics (MD) simulations has been long sought. Recently, Shan et al. (4) reported in situ straining dark-field transmission electron microscope (DFTEM) observations ...
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ژورنال
عنوان ژورنال: Proceedings of the National Academy of Sciences
سال: 2009
ISSN: 0027-8424,1091-6490
DOI: 10.1073/pnas.0901765106