On the Brownian coagulation of nanosized oxide particles in ODS materials under irradiation and annealing conditions

Abstract

Recent experiments on ion irradiation of oxide dispersion strengthened (ODS) materials to high doses at 500 °C performed at the CEA-JANNuS-Saclay facility, in which nanosized oxide particles exhibited changes in the size distribution resulting in a decrease of the number density and an increase of the average nanoparticle size, are analysed. It is shown that the nanoparticle size coarsening observed either in the irradiation tests (at 500 °C) or in the annealing tests (at 1300 °C) can be described self-consistently within the Brownian coagulation theory. The developed model gives also a reasonable prediction for the coarsening of nanosized particles under neutron irradiation, observed in the commercial ODS alloy MA957 irradiated in the French fast breeder reactor Phénix.