The 9th International Conference on Multiscale Materials Modeling

講演情報

Symposium

C. Crystal Plasticity: From Electrons to Dislocation Microstructure

[SY-C1] Symposium C-1

2018年10月29日(月) 13:30 〜 15:15 Room1

Chair: Emmanuel Clouet(CEA Saclay, SRMP, France)

[SY-C1] Modeling the climb-assisted glide of edge dislocations through a random distribution of nanosized vacancy clusters

Marie Landeiro Dos Reis1, Laurent Proville1, Maxime Sauzay2, Mihai Cosmin Marinica1, Normand Mousseau3 (1.SRMP-CEA Saclay, France, 2.SRMA-CEA Saclay, France, 3.Département de Physique, Université de Montréal , Canada)

A multi-scale model is developed to simulate the climb-assisted glide of edge dislocations anchored by a random distribution of nanosized vacancy clusters. For a shear stress much smaller than the critical stress beyond which dislocations cross the obstacles by simple glide, we found that dislocations remain anchored for a waiting time sufficient to allow the diffusion-controlled absorption of vacancies. Then the dislocations climb perpendicularly to their glide planes up to circumvent the obstacles and subsequently glide until they encounter a different anchoring configuration. Atomic-scale simulations allowed us to characterize the interactions between an edge dislocation and nano-voids as a function of their sizes and shapes. Our atomic-scale data served to calibrate an elastic-line model which we used to evaluate the glide distance of a dislocation with realistic dimensions through a random distribution of obstacles. To complete our scheme, a standard diffusion-based model for the climb velocity of edge dislocations was used to determine the deformation rate expected through the climb-assisted glide. Our predictions made for the archetypical case of Al are in good agreement with experiments of different types, i.e. tensile deformation tests and steady-creep tests, although no parameter was adjusted in the theory to recover experimental data.