<100> SIL formation from two 1/2<111> SILs under 1/2<111> edge dislocation
George Zhang
Department of Materials Science & Engineering, University of Tennessee
This page shows formation of <100> SIL from two 1/2<111> SILs under the tensile region of 1/2<111> edge dislocation in bcc Iron. These structures were created by George Zhang
<100> interstitial dislocation loops are a critical form of radiation damage in bcc iron, contributing to void swelling and radiation embrittlement, yet their formation mechanism remains incompletely understood. Although applied stress has been shown computationally to promote the bi-loop reaction between two 1/2<111> loops, the strain levels required far exceed realistic macroscopic service conditions. Edge dislocations, which are ubiquitous in structural materials and generate intense local stress fields near their cores, represent a physically realistic alternative stress source. Experimental evidence further shows that <100> loops preferentially nucleate in the tensile regions of pre-existing dislocation lines, motivating a direct atomistic investigation of this effect. Self-Evolving Atomistic Kinetic Monte Carlo simulations were performed on a bcc Fe system containing a 1/2<111> edge dislocation and two 1/2<111> self-interstitial loops. The results show that the dislocation tensile field reduces the key transition barrier and reveals two distinct transition pathways. The dominant pathway produces <010>, <001>, and 1/2<111> product loops exclusively through non-conservative reactions, with product orientations distinct from those observed in stress-free conditions.
Interactive Structures
Color Legend:
- reddish brown = Fe atoms in 1/2<111> SIL
- gray = Fe atoms in <100> SIL
- light green = Fe atoms around 1/2<111> edge dislocation
References
1. H.X. Xu, R.E. Stoller, Y.N. Osetsky, D. Terentyev, "Solving the Puzzle of <100> Interstitial Loop Formation I bcc Iron", Physical Review Letters, 110, 265503 (2013), doi: 10.1103/PhysRevLett.110.265503
2. H.B. Zhou, X.Y. Tang, Y.H. Li, H.X. Yang, H.X. Huang, Q.Y. Ren, G.H. Lu, "Elucidating the mechanism of strain-driven <100> dislocation loop formation in bcc iron
", Transactions of Materials Research, 1, 1, 100008 (2025), doi: https://doi.org/10.1016/j.tramat.2025.100008
3. Y. Li, Z.H. Qi, A. Bhattacharya, S.J. Zinkle, "Temperature and dose effects on dislocation loops in self-ion irradiated high-purity iron", Acta Materialia, 296, 121235 (2025), doi: https://doi.org/10.1016/j.actamat.2025.121235
posted: May 2026.
updated: May 2026.