Elastic limit for surface step dislocation nucleation in face-centered cubic metals: Temperature and step height dependence

The influences of surface step state and temperature on the elastic limit for dislocation nucleation from a surface step were analyzed by means of atomic scale simulations in face-centered cubic metals. When varying the step height, two regimes were found: for smaller steps, local effects dominate,...

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Bibliographic Details
Published in:Acta materialia 2010-07, Vol.58 (12), p.4182-4190
Main Authors: Brochard, S., Hirel, P., Pizzagalli, L., Godet, J.
Format: Article
Language:English
Subjects:
Activation analysis
Aluminum
Applied sciences
Dislocation nucleation
Dislocations
Elastic limit
Exact sciences and technology
MD simulations
Mechanical properties and methods of testing. Rheology. Fracture mechanics. Tribology
Metals. Metallurgy
Nanocomposites
Nanomaterials
Nanostructure
Nucleation
Plastic deformation
Simulation
Surface
Thermally activated processes
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Summary:The influences of surface step state and temperature on the elastic limit for dislocation nucleation from a surface step were analyzed by means of atomic scale simulations in face-centered cubic metals. When varying the step height, two regimes were found: for smaller steps, local effects dominate, whereas for larger steps, the stress concentration prevails. The differences observed for the elastic limit were correlated to relevant properties of the different potentials. Finally, for aluminum, the implication of the activation parameters in the nucleation strain was studied in greater detail. This study is particularly relevant to nanostructures, where plasticity is most often governed by dislocation nucleation rather than dislocation multiplication.
ISSN:1359-6454
1873-2453
DOI:10.1016/j.actamat.2010.04.009