New insights into spatio-temporal dynamics of irradiation defects rafting

Abstract

The self-organization of irradiation defects has continuously attracted numerous experimental and theoretical attentions, due to its influence on the service performance of irradiated materials. This work developed the discrete dislocation dynamics method by considering the thermal fluctuations, in order to statistically clarify the contribution of elastic interactions and thermal fluctuations to the temporal and spatial dynamics of raft formation. On temporal scales, this work for the first time demonstrates the existence of power-law scaling of raft formation time, and its insensitivity to the thermal fluctuations, and loop size distribution. The power-law exponent is consistent with many other self-organized critical phenomena, such as earthquakes, sandpile sliding, and dislocation avalanches, etc. On spatial scales, the deviation between the normal direction of the raft habit plane and the Burgers vector of the irradiation-induced interstitial loops was carefully analyzed, which agrees well with the experimental results.