A study by Prof. MA, Kan et al. published in Science Advances has revealed a novel approach to distinguishing interstitial and vacancy-type dislocation loops in face-centered cubic (FCC) materials. They have demonstrated that the morphology of radiation-induced Frank loops can serve as a reliable indicator of their nature, offering an advancement in characterisation radiation damage in structural materials.

The study found that circular loops are consistently interstitial-type across all FCC materials, while segmented loops exhibit a vacancy-type nature in high stacking fault energy (SFE) alloys but vary in low SFE and high-entropy alloys. This correlation is attributed to the dissociation of an a0/3<111> dislocation into an a0/6<112> Shockley partial and an a0/6<110> stair-rod dislocation. The dissociation of vacancy loops occurs naturally, whereas interstitial loops require external stimuli to promote the dissociation.
This discovery provides an efficient method for identifying the dislocation loop nature, eliminating the need for complex imaging techniques. The findings have broad implications for radiation damage research, particularly in developing radiation-resistant materials for nuclear reactors and other high-radiation environments. The study also opens new avenues for investigating dislocation loops in hexagonal close-packed (HCP) materials, potentially expanding its relevance beyond FCC structures. By establishing a clear morphology-nature correlation, this research enhances our ability to predict and mitigate radiation-induced defects, paving the way for stronger, more resilient materials in critical applications.

For more details, please read the full article in Science Advances.