What is it about?

Numerical simulations aiming at capturing the features of plastic deformation in metals require all together, the accurate modeling of cohesion of the studied metal, boundary conditions that consistently reproduce dislocation states in real crystals and the proper accounting of temperature effects. In this work, a new set of boundary conditions is proposed for molecular simulations of isolated elastic defects such as cracks, dislocations and elastic inclusions. The case study of the <111> screw dislocation in body centered cubic (bcc) tungsten, modeled via a phenomenological, n-body cohesion functional, serves to validating the new boundary conditions by computing structural properties of this defect and by comparing these with results from the literature.

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Why is it important?

The new boundary conditions allow for simulating elastic defects embedded in an infinitely extended discrete atomic system, by elegantly overcoming the limitations relating to the translational symmetry breakdown in presence of such structural defects. Thereby, their the unbiased study at the atomic scale becomes possible with minimal changes of the simulation codes.


Ongoing and future work is about applying the methodology to simulations of dislocations with mixed character and of other elastic defects such as elastic inclusions and cracks.

Vassilis Pontikis
CEA - Commissariat à l'Energie Atomique et aux Energies Alternatives

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This page is a summary of: Boundary conditions for molecular simulations of isolated elastic defects. Case study: The ⟨111⟩ screw dislocation in bcc W, Journal of Applied Physics, July 2022, American Institute of Physics,
DOI: 10.1063/5.0090621.
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