title: Atomistic modeling of carbon Cottrell atmospheres in bcc iron.
abstract: Atomistic simulations with an EAM interatomic potential were used to evaluate carbon-dislocation binding energies in bcc iron. These binding energies were then used to calculate the occupation probability of interstitial sites in the vicinity of an edge and a screw dislocation. The saturation concentration due to carbon-carbon interactions was also estimated by atomistic simulations in the dislocation core and taken as an upper limit for carbon concentration in a Cottrell atmosphere. We obtained a maximum concentration of 10 ± 1 at.% C at T = 0 K within a radius of 1 nm from the dislocation lines. The spatial carbon distributions around the line defects revealed that the Cottrell atmosphere associated with an edge dislocation is denser than that around a screw dislocation, in contrast with the predictions of the classical model of Cochardt and colleagues. Moreover, the present Cottrell atmosphere model is in reasonable quantitative accord with the three-dimensional atom probe data available in the literature.
authors.affiliation: Escola Politécnica/Departamento de Engenharia Metalúrgica e de Materiais, Universidade de São Paulo, Brazil. rgaveiga@usp.br
authors.forename: R G A
authors.initials: RG
authors.lastname: Veiga
authors.forename: M
authors.initials: M
authors.lastname: Perez
authors.forename: C S
authors.initials: CS
authors.lastname: Becquart
authors.forename: C
authors.initials: C
authors.lastname: Domain
mesh_terms: D002244:Carbon / Q000737:chemistry*; D003198:Computer Simulation; D004735:Energy Transfer; D007501:Iron / Q000737:chemistry*; D008956:Models, Chemical; D008958:Models, Molecular; D011312:Pressure
chemical_list: D002244:Carbon; D007501:Iron