Dislocation loop nucleation in irradiated metals

Nucleation and growth of interstitial dislocation loops in irradiated aluminum

“…It was established that the values of the parameters of dislocation loop nucleation obtained in the context of the classical theory [2][3][4] and within the kinetic model [1,5] were almost the same. The values of the number of interstitial atoms in the dumbbell configuration in nuclei of critical and supercritical sizes (n c = 2 and n 0c = 3, respectively) obtained for fcc aluminum coincide with analogous data for irradiated bcc vanadium [1].…”

“…The obtained results indicate that the correct anal ysis of parameters of nucleation of interstitial disloca tion loops in irradiated metals can be carried out in the context of both the classical nucleation theory [2][3][4] and the kinetic model [1,5].…”

“…Analysis of experimental data on nucleation of interstitial dislocation loops in irradiated vanadium [1] within classical nucleation theory [2][3][4] and kinetic model [5] has allowed us to determine the parameters of the process of formation and growth of loops. In this work, we analyze experimental data on loop formation in pure aluminum irradiated with electrons.…”

Nucleation of interstitial dislocation loops in metals under electron irradiation

“…The rate of variation of C i2 is (8) From (8), we obtain (9) where K i is the reaction constant of the formation of dumbbell interstitial atoms and τ 2 is the nucleation time of these complexes. Since the diffusion mobility of interstitial atoms is very high and their dynamic concentration C i quickly saturates, one may use a qua sistationary approximation to represent (9) in a sim pler form: (10) Hence, it follows that (11) where (12) Upon further irradiation, the general concentra tion of interstitial atoms in complexes (n) increases only owing to their growth, whereas the concentration C 2 remains constant because absorption efficiency f(n) of freely migrating interstitial atoms in the complexes consisting of more than two atoms (n > 2) is greater than that for the reaction of dumbbell formation where f(n) = 1. The corresponding growth sequence of the general concentration of interstitial atoms in com plexes has the form (13) The rate of variation of the general concentration of interstitial atoms in triple atom complexes has the form (14) where f(n) = 2.…”

“…It is worth noting that, except our studies [12,13], function f(n) of loops was taken in the form f(n) = n 1/2 in other known works under the assumption that freely migrating point defects are captured by interstitial atoms localized along the perimeter of the loop. At the same time, as follows from analogous dispersion anal ysis of the size distribution of dislocation loops in alu minum irradiated with electrons [7], the result is neg ative in that case.…”