Effect of crystal defects in iron on carbon diffusivity: Analytical model married to atomistics

We devise a scheme for simulating diffusion of interstitial solutes in metals when the diffusivity is modified by the presence of defects. The method is quite general and may be used to model the effects of more than one defect in combination. In addition, it is amenable to being described by a simple analytic model fitted to a small number of parameters that can be determined by computer experiments. Using classical interatomic potentials and molecular dynamics, we calculate the diffusivity of carbon in iron and study the effects of a substitutional alloying element and an edge dislocation. Some of our results are validated against published experimental findings and previous simulations, and we are able to apply our theoretical model to rationalize our results and to show how, once the model is fitted to the computer experiments, it may be used in a predictive manner.