Flux effects on point defect behavior by tracking loop evolution using combined irradiation method

Irradiation flux effects are directly related to the behavior of point defects, and it is challenging to observe them experimentally. During combined irradiation, the interstitial loops produced after the first irradiation proved to be good indictors of point defect behaviors during the second irradiation with different fluxes (similar to 50 times of difference). For specimens without Si, the growth of pre-existing interstitial loops in the second irradiation was more distinct at lower flux, whereas the number density of nucleated defects was significantly larger at higher flux. This was attributed to the long-range diffusion of interstitials toward pre-existing sinks in the low-flux irradiation. When the flux was high, such long-range diffusion was interrupted by the rapid production of cascades and point defects. For specimens with Si, the long-range diffusion was hindered by the interstitial trapping effect of Si, which was assumed to reduce the difference between the low-flux and high-flux irradiation. (C) 2021 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.

Automated summary

Irradiation flux effects are directly related to the behavior of point defects, which can be indicated by the growth of interstitial loops and the number density of nucleated defects during different flux irradiation. Long-range diffusion of interstitials towards pre-existing sinks plays a significant role in low-flux irradiation, while it is interrupted by rapid defect production in high-flux irradiation. The presence of Si hinders long-range diffusion due to the interstitial trapping effect, reducing the differences between low-flux and high-flux irradiation.