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Overdamped langevin dynamics simulations of grain boundary motion
No full textInternational audienceMacroscopic properties of structural materials are strongly dependent on their microstructure. However, the modeling of their evolution is a complex task because of the mechanisms involved such as plasticity, recrystallization, and phase transformations, which are common processes taking place in metallic alloys. This complexity led to a growing interest in atomistic simulations formulated without any auxiliary hypotheses beyond the choice of interatomic potential. In this context, we propose here a model based on an overdamped stochastic evolution of particles interacting through inter-atomic forces. The model settles to the correct thermal equilibrium distribution in canonical and grand-canonical ensembles and is used to study the grain boundary migration. Finally, a comparison of our results with those obtained by molecular dynamics shows that our approach reproduces the complex atomic-scale dynamics of grain boundary migration correctly
Peak intrinsic thermal conductivity in non-metallic solids and new interpretation of experimental data for argon
No full textA Diffuse Interface Model for Void Formation under Non-Equilibrium Irradiation
No full textABSTRACTVoid formation in irradiated materials is an intriguing and technologically important physical process associated with radiation damage. In this communication, we present a diffuse interface model for simulating void formation in materials under irradiation. Voids are treated as aggregates of vacancies left from the cascade damage. The emergence of the void ensembles in the irradiated material is modeled by an Allen-Cahn equation coupled with two Cahn-Hilliard equations governing the space and time evolution of vacancies and interstitials. The governing system of equations includes stochastic generation of point defects representing the cascade process, reaction of vacancies and interstitials, interaction of point defects with extended defects (viz., void surface and grain boundaries) and thermal fluctuations in defects. Numerical simulations demonstrating the model capabilities with respect to nucleation and growth of voids and swelling of the irradiated material are presented.</jats:p
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