Vacancy-carbon complexes in bcc iron: Correlation between carbon content, vacancy concentration and diffusion coefficient

Self-diffusion in face-centered cubic (fcc) iron and hexagonal close-packed cobalt as well as Ni diffusion in bcc iron and Co-diffusion in fcc nickel are all accelerated in the presence of dissolved carbon. This is attributed to an enlarged vacancy concentration due to an attractive vacancy carbon interaction. The enlarged Ni diffusion in body-centered cubic (bcc) iron contradicts conclusions for self-diffusion in bcc iron obtained from first-principles calculations. This discrepancy is discussed in the present study. (C) 2013 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.