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Measurements of the electrical resistivity on nickel specimens almost free of dislocations were performed during irradiation with 1.85 MeV electrons. Results are reported for irradiation temperatures varying between -80 C and -40 C and for production rates varying between 2 x 1.0 E-11 and 5.8 x 1.0 E-10 dpa/s. It was found that the electrical resistivity per Frenkel defect varies with the measuring temperature, yielding a value of 2.33 x 1.0 E-4 at -60 C. Interstitials are not mobile for irradiation temperatures below -60 C and quasi steady state defect concentrations are obtained for irradiation temperatures higher than -45 C. The results are compatible with the finding that the migration activation energy of interstitials decreases with increasing high energy particle flux, from a value of 1.03 eV without irradiation to 0.885 eV for a production rate of 3.46 x 1.0 E-10 dpa/s. It was found also that di-interstitials are formed in situ when an existing interstitial encounters a dynamic crowdion. Di-interstitials are very mobile at an irradiation temperature of -60 C, initiating the formation of interstitial clusters which are enriched in undersized impurity atoms, such as silicon. In the presence of large interstitial clusters or precipitates, the migration activation energy of interstitials decreases further.

Additional information

Authors: SCHÜLE W, JRC Ispra (IT)
Bibliographic Reference: Paper presented: 16th International Symposium on the Effects of Radiation on Materials, Denver (US), June 23-25, 1992
Availability: Available from (1) as Paper EN 36820 ORA
Record Number: 199210715 / Last updated on: 1994-12-02
Original language: en
Available languages: en