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Journal Articles International Journal of Plasticity Year : 2021

Surface effects on image stresses and dislocation pile-ups in anisotropic bi-crystals

Abstract

Based on the image decomposition method and the Leknitskii-Eshelby-Stroh (LES) formalism, the effects of surface conditions and misorientation on the dislocation image stress and dislocation distributions in double-ended discrete dislocation pile-ups are studied in a new bi-crystal surface layer configuration. This new configuration contains a stiff layer of finite thickness adjacent to the free surface, which influences the dislocation image stress. The numerical method is first applied to different half-space and bi-crystal configurations for Ni. It is shown that the stiff layer significantly modifies the profile of the dislocation image stress compared to a free or rigid surface. A size effect on the dislocation image stress is found when considering two parallel free surfaces. In addition, the effect of each free surface is individually analyzed. Meanwhile, a grain size effect is also found when considering two parallel grain boundaries. In a second application, the numerical study of a double-ended dislocation pile-up model is proposed, terminating on a grain boundary on one side and on a stiff layer adjacent to a free surface on the other side. The effects of surface conditions, grain boundary and critical stress on dislocation distributions in the double dislocation pile-up are analyzed both at loading and unloading in the case of Ni bi-crystals.
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Dates and versions

hal-03157931 , version 1 (03-03-2021)

Licence

Attribution - NonCommercial - NoDerivatives

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Xiaolei Chen, Thiebaud Richeton, Christian Motz, Stéphane Berbenni. Surface effects on image stresses and dislocation pile-ups in anisotropic bi-crystals. International Journal of Plasticity, 2021, pp.102967. ⟨10.1016/j.ijplas.2021.102967⟩. ⟨hal-03157931⟩
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