| Abstract Scope |
After electron-, neutron-, and ion-irradiations, researchers have observed <001> dislocation loops in BCC Fe system. Classical dislocation theory posits that <001> loops are energetically less favorable than ½<111> loops, but <001> fraction can approach 100% in experiments. This discrepancy indicates that there is a potential gap between experiments and dislocation theory. More than a dozen models have been proposed, and each model exclusively addresses a specific physical mechanism. However, as dynamic phenomena, irradiations involve multiple processes starting from cascade events, leading to that experimental observations are collective outcomes of these processes. Currently, the most plausible <001> production hypotheses are interaction between glissile ½ <111> loops. In this presentation, we demonstrate the importance of interaction models. By exploiting the inherent mobility of ½<111> loops, we isolate the loop interaction process from concurrent irradiation-related phenomena in regions deeper than the penetration depth of 6.7-8 MeV self-ions. We report that the <001> loop fraction beyond the ion irradiation damage region can be tuned from ~10% to 80% by varying crystal orientations between major zone axis, temperatures (350-500°C), and pre-implanted He bubble distributions. Furthermore, synchrotron diffraction analysis is employed to investigate the influence of strain fields, emanating from the irradiated region, on the mean free paths of migrating ½<111> loops. |