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Journal Articles Physical Review Materials Year : 2020

Atomic scale simulations for the diffusion assisted crossing of dislocation anchored by vacancy clusters

Abstract

Nano-size vacancy clusters, characterized in metals after plastic deformation, irradiation or specific heat treatments are suspected to participate to materials hardening through their interactions with mobile dislocations. Our numerical simulations made from combining 3 different simulation techniques, \textit{i.e.} molecular statics, kinetic Monte Carlo and elastic line models allow us to compute the dislocations velocity in realistic conditions of applied shear stress, temperature, concentration and size of the vacancy clusters, in face centered cubic aluminium. We show that the clusters behave as sources of vacancies that follow a reaction path along the dislocation line, which is recognized as a pipe diffusion process. The accumulation of vacancies in the dislocation stacking fault ribbon yields jogs that participate to the dislocation climb. Both vacancy leaks from clusters and climb of dislocation segments contribute to the dislocation crossing which remains though thermally activated. We integrated the ensemble of the thermally activated processes: diffusion, emission, absorption processes as well as dislocation-cluster crossing into the same simulation allowing us to predict the dislocation mobility in good agreement with experimental deformation tests.
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Dates and versions

cea-02958786 , version 1 (06-10-2020)

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Marie Landeiro dos Reis, Laurent Proville, Mihai Cosmin Marinica, Maxime Sauzay. Atomic scale simulations for the diffusion assisted crossing of dislocation anchored by vacancy clusters. Physical Review Materials, 2020, 4, pp.103603. ⟨10.1103/PhysRevMaterials.4.103603⟩. ⟨cea-02958786⟩
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