Decoding the interstitial/vacancy nature of dislocation loops with their morphological fingerprints in face-centered cubic structure.
basic_science · Level V
Where this comes from
- Record sourced from PubMed, PMID 40215304.
- Also identified by DOI 10.1126/sciadv.adq4070 and PMC identifier 11988408.
- Licence recorded as CC BY.
- The licence permits redistribution, so the abstract is shown in full and the full text is available from the publisher.
Abstract
Dislocation loops are critical defects inducing detrimental effects like embrittlement and swelling in materials under irradiation. Distinguishing their nature (interstitial- or vacancy-type) is a long-standing challenge with great implications for understanding radiation damage. Here, we demonstrate that the morphology of radiation-induced Frank loops can unveil their nature in face-centered cubic (fcc) structure: Circular loops are interstitial-type in all fcc materials, while segmented loops are vacancy-type in high stacking fault energy (SFE) alloys but varied-type in low SFE and high-entropy alloys. The polygonal shape is attributed to the dissociation of an <i>a</i><sub>0</sub>/3<111> dislocation into an <i>a</i><sub>0</sub>/6<112> Shockley partial and an <i>a</i><sub>0</sub>/6<110> stair-rod dislocation. The dissociation of vacancy loops is energetically favorable, whereas interstitial loops require external stimuli to promote dislocation propagation. This "morphology-nature" correlation not only highlights the asymmetry of vacancy/interstitial loops but also offers an efficient way to distinguish loop nature for a wide range of materials.