title: "Conjugate channeling" effect in dislocation core diffusion: carbon transport in dislocated BCC iron.
abstract: Dislocation pipe diffusion seems to be a well-established phenomenon. Here we demonstrate an unexpected effect, that the migration of interstitials such as carbon in iron may be accelerated not in the dislocation line direction ξ, but in a conjugate diffusion direction. This accelerated random walk arises from a simple crystallographic channeling effect. c is a function of the Burgers vector b, but not ξ, thus a dislocation loop possesses the same everywhere. Using molecular dynamics and accelerated dynamics simulations, we further show that such dislocation-core-coupled carbon diffusion in iron has temperature-dependent activation enthalpy like a fragile glass. The 71° mixed dislocation is the only case in which we see straightforward pipe diffusion that does not depend on dislocation mobility.
authors.affiliation: Akio Ishii Department of Mechanical Science and Bioengineering, Osaka University, Osaka, Japan. akio.ishii@tsme.me.es.osaka-u.ac.jp
authors.forename: Akio
authors.initials: A
authors.lastname: Ishii
authors.forename: Ju
authors.initials: J
authors.lastname: Li
authors.forename: Shigenobu
authors.initials: S
authors.lastname: Ogata
mesh_terms: D002244:Carbon / Q000737:chemistry*; D004058:Diffusion; D007501:Iron / Q000737:chemistry*; D008956:Models, Chemical; D056004:Molecular Dynamics Simulation; D013696:Temperature
chemical_list: D002244:Carbon; D007501:Iron