Connecting atomistic and continuous descriptions of grain boundaries to investigate their migration in fcc polycristals

par Etienne Ngenzi

Projet de thèse en Doc sciences des materiaux

Sous la direction de Yann Charles.

Thèses en préparation à Paris 13 , dans le cadre de École doctorale Galilée (Villetaneuse, Seine-Saint-Denis) depuis le 10-11-2018 .

  • Pas de résumé en français disponible.

  • Résumé

    This project will benefit from ongoing efforts carried at UP13 and UCLA by one PhD work and one postdoctoral fellow, respectively (see section 2). In particular, we have at our disposal all the required MD tools to i) generate arbitrary GB, ii) analyze their atomic structures and iii) measure their motion. The PF model has been successfully implemented into an ‘internal-consumption‘ code. New technical developments for this work are expected to be limited. With the objective to provide a full 3D unified framework, our simulations will explore the 5D parametric space of GB geometry. Despite recent successes [5,16], this task remains a serious undertaking, we will leverage our recent results on Ni to define the scope of the work. Special attention will be provided to <111> GB and the GB found in our experimental samples of task 3. <111> GB are interesting for various reasons: i) they are largely represented for symmetry reasons in fcc polycrystals and ii) they are often considered as fast (certainly thanks to a favored interaction with a/2<110> dislocations of the bulk). The study will focus on Ni as a fcc model material and since we can reuse a number of available results. The recruited PhD student will be involved in the numerical part of the work of task 1-3, in close collaboration with the other persons involved.