Energy barriers for carbon migration in the neighborhood of line defects in body-centered cubic iron were obtained by atomistic simulations. For this purpose, molecular statics with an Fe-C interatomic potential, based on the embedded atom method, was employed. Results of these simulations were compared to the predictions of anisotropic elasticity theory. The agreement was better for a carbon atom sitting on an octahedral site (energy minimum) than one on a tetrahedral site (saddle point). Absolute differences in the energy barriers obtained by the two methods were usually below 5meV at distances larger than 1.5nm from a screw dislocation and 2nm (up to 4nm in the glide plane) from the edge dislocation. Atomistic kinetic Monte Carlo simulations performed at 300K and additional analysis based on the activation energies obtained by both methods showed that they were in good qualitative agreement, despite some important quantitative discrepancies due to the large absolute errors found near the dislocation cores.

Comparison of Atomistic and Elasticity Approaches for Carbon Diffusion near Line Defects in α-Iron. R.G.A.Veiga, M.Perez, C.S.Becquart, E.Clouet, C.Domain: Acta Materialia, 2011, 59[18], 6963-74