Material Science Division, Joint Research Centre, Ispra Establishment,
Pages: 13 Published: Jan 1987
Results of investigations of radiation enhanced diffusion on copper-15at% aluminum alloys are reported where the electron flux, the irradiation temperature, and the thickness d of the specimens are varied. The activation energy of ordering or of diffusion is Qirr = 0.355 eV for an electron current density of 4.25 μA cm−2 almost independent of d. Qirr increases slightly with decreasing flux, and Qirr = 0.377 eV is found for 0.04 μA cm−2 and 0.1-mm-thick specimens. This behavior is in agreement with the assumptions that (1) the migration energy of vacancies EM1V decreases with increasing flux and (2) interstitials have to jump about 30 times more often than vacancies in order to change the degree of order by the same amount. It is further found that small sink concentrations cause an acceleration of the ordering rate rather than a decrease of this quantity through an increase of the mobility of the defects.
In copper-aluminum alloys almost no sinks for point defects are formed during irradiation; thus defects annihilate mainly by pair recombination even at low irradiation temperatures in contrast to results obtained for many other alloys.
radiation damage, radiation enhanced diffusion, diffusion mechanisms, properties of point defects, annealing mechanisms of point defects
Paper ID: STP33804S