Isotope Effect in Self-Diffusion in Iron

The isotope effect in self-diffusion was measured in the δ, γ, and α phases of Fe using a new isotope pair, Fe⁵²-Fe⁵⁹. The isotope-effect data, together with measurements taken on the effect of Co solute additions on Fe self-diffusion, were used to deduce the most likely mechanisms for self-diffusion in all three phases. The data are consistent with a vacancy mechanism in fcc γ-Fe. In bcc α- and δ-Fe, the data are consistent with a vacancy or interstitialcy mechanism. The mechanism seems to be the same in δ- and in α-Fe.