Impurity effects on He diffusion in α-Fe

The diffusion of He in α-Fe in the presence of defects produced by irradiation (vacancies and self-interstitials) is studied using rate theory models with input from ab initio calculations. Comparison between the model based on He in pure Fe and experimental data of He desorption obtained in different conditions shows discrepancies. This disagreement is attributed to the presence of carbon in the experimental samples. An extended model for the kinetics of He in α-Fe including carbon is presented. Results obtained with this model are in good agreement with experimental He desorption data.