The radiation-enhanced self-diffusion coefficients of 55Fe in almost dislocation-free monocrystals of α-Fe were determined, after irradiation with 1.85MeV electrons, by means of sputtering. The diffusion coefficients which were measured following irradiation at 430 to 730K were surprisingly large and depended upon the irradiation temperature. An analysis of the data revealed that radiation-induced point defects annihilated during irradiation; mainly via pair recombination. Self-interstitials were the rate-determining point detects which were responsible for the observed large diffusion coefficients. It was found that the activation energy for the migration of self-interstitials decreased, with increasing high-energy particle flux, from 0.55 to 0.41eV for a point-defect production rate of 1.85 x 10-10/dpa. The present value (0.55eV) of the activation energy for self-interstitial migration was the same as that reported for recovery-stage III after irradiation with high-energy particles. It was concluded that self-interstitials in α-Fe migrated and annihilated in recovery-stage III after irradiation with high-energy particles. The basic features of the modified 2-interstitial radiation damage model for face-centered cubic materials were suggested to be valid for body-centered cubic materials as well.

Radiation-Enhanced Self-Diffusion in α-Iron. W.Schule: Zeitschrift für Metallkunde, 2000, 91[9], 728-33