Atomistic simulations of the nucleation of He clusters and bubbles in bcc iron at 800 K have been carried out using the newly developed Fe-He interatomic potential, along with Ackland potential for the Fe-Fe interactions. Microstructure changes were analyzed in detail. We found that a He cluster with four He atoms is able to push out an iron interstitial from the cluster, creating a Frenkel pair. Small He clusters and self-interstitial atom (SIA) can migrate in the matrix, but He-vacancy (He-V) clusters are immobile. Most SIAs form clusters, and only the dislocation loops with a Burgers vector of b =1/2 appear in the simulations. SIA clusters (or loops) are attached to He-V clusters for He implantation up to 1372 appm, while the He-V cluster-loop complexes with more than one He-V cluster are formed at the He concentration of 2057 appm and larger.
Revised: January 8, 2016 |
Published: May 15, 2013
Citation
Yang L., H. Deng, F. Gao, H.L. Heinisch, R.J. Kurtz, S.Y. Hu, and Y. Li, et al. 2013.Atomistic studies of nucleation of He clusters and bubbles in BCC iron.Nuclear Instruments and Methods in Physics Research. Section B, Beam Interactions with Materials and Atoms 303.PNNL-SA-92902.doi:10.1016/j.nimb.2012.11.025