Growth kinetics and ‘preference factor’ of Frank loops in nickel during electron irradiation

Abstract

The growth kinetics of interstitial-type Frank loops in a thin foil of high purity Ni at 450°C has been measured during electron irradiation in a HVEM operating at 650 kV. The depth positions of the loops with respect to the foil surfaces were determined by stereomicroscopy. The experimental data were analysed by use of the general rate-theory model which takes into account both temporal and spatial dependence of loop growth. It is found from systematic variations of the vacancy migration energy, E _vm, and the preference factor of dislocation loops for self-interstitials, δ_i, that E_vm = 1·2 eV and δ_i = 0·06, which together yield reasonable agreement between the theoretical model and the experimental data.