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