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Results of investigations of the diffusion rate of nickel-10.6 % chromium alloys after plastic deformation, after quenching from 700 C and from 1030 C, and during irradiation with 18 MeV protons and 1.85 MeV electrons are reported. The diffusion rate is measured by means of electrical resistivity which increases with increasing degree of short range order. The characteristic temperature below which short range order develops is 550 C. Below about 400 C the atomic mobilities of the component atoms of the alloy are so small that no further increase in the degree of short range order is found in due laboratory times. For the migration activation energies of interstitials and vacancies values of E(M)(II) = 1.04 eV and E(M)(IV) = 1.16 eV are derived from results of measurements of radiation enhanced diffusion, respectively. These values decrease with increasing high energy particle flux. A vacancy diffusion mechanism is rate determining during irradiation for the increase of the degree of short range order. Interstitials have to jump about 150 times more often than vacancies for the degree of short range order to increase by the same amount. The characteristic temperature for interstitial cluster formation is 300 C. Above this temperature radiation-induced interstitials and vacancies annihilate mainly by pair recombination. Above about 380 C the radiation enhanced diffusion rate is surprisingly much smaller than the thermal diffusion rate. The quasi-dynamic vacancy concentration built up during irradiation is much smaller than the thermal vacancy concentration.

Additional information

Authors: GIEB M, JRC Ispra (IT);HEIECK J, JRC Ispra (IT);SCHÜLE W, JRC Ispra (IT)
Bibliographic Reference: EUR 15793 EN (1994) 29 pp., free of charge
Availability: Available from Joint Research Centre, Publication Department, I-21020 Ispra (Va.) (IT)
Record Number: 199410879 / Last updated on: 1995-03-21
Original language: en
Available languages: en
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