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Interstitial Cluster with C-15 Structure Created by Cascades in bcc Iron

This page shows visualizations of the interstitial cluster with C-15 structure created by cascades in bcc Iron. These structures were created by Dr. Haixuan Xu, Dr. Haixuan Xu, Dr. Roger E. Stoller, and Dr. Yury N. Osetsky in the Materials Science and Technology Division at the Oak Ridge National Laboratory.

Determining defect evolution beyond the molecular dynamics (MD) time scale is critical to bridging the gap between atomistic simulations and experiments. The recently developed self-evolving atomistic kinetic Monte Carlo (SEAKMC) method provides new opportunities to simulate long-term defect evolution with MD-like fidelity to the atomistic processes involved. To demonstrate this capability, three examples are presented in which SEAKMC has been used to investigate the evolution of typical radiation- induced defects in bcc iron. Depending on the particular example, SEAKMC results are compared with those obtained using two other on-the-fly KMC techniques, object KMC, and MD. The three examples are: (1) evolution of a vacancy-rich region similar to the core of a displacement cascade, (2) the stability of recently reported interstitial clusters with a structure similar to the C15 Laves phase, and (3) long-term aging of atomic displacement cascade debris. In the various examples, the SEAKMC approach provides better agreement with MD simulations, highlights the importance of the underlying atomistic processes, and provides new information on long-term defect evolution in iron.1

Interactive Structures

Color Legend:

  • reddish brown = interstitial
  • tan = vacancy


1. H.X. Xu, R.E. Stoller, Y.N. Osetsky, "Cascade defect evolution processes: Comparison of atomistic methods", Journal of Nuclear Materials, 443, 66-70 (2013), doi: 10.1016/j.jnucmat.2013.07.001

posted: July 2014.
updated: July 2014.