Eur. Phys. J. B (2013) 86: 118
https://doi.org/10.1140/epjb/e2013-30778-y

Regular Article

Self-interstitial clusters in radiation damage accumulation: coupled molecular dynamics and metadynamics simulations

¹ Department of Nuclear Science and Engineering, Massachusetts Institute of Technology, Cambridge, MA 02139, USA
² Department of Materials Science and Engineering, Massachusetts Institute of Technology, Cambridge, MA 02139, USA

^a e-mail: paul.monasterio@gmail.com
^b e-mail: syip@mit.edu
^c e-mail: byildiz@mit.edu

Received: 26 August 2012
Received in final form: 20 January 2013
Published online: 27 March 2013

Abstract

Self-interstitial interactions causing volume expansion in bcc Fe are studied through an idealized microstructure evolution model in which only self-interstial atoms (SIAs) are inserted. Using a combination of non-equilibrium molecular dynamics simulations and a metadynamics algorithm, meta-stable SIA clusters are observed to nucleate and grow into dislocation loops or localized amorphous phases, both contributing to swelling behavior persisting well beyond the atomistic time scale. A non-monotonic local density variation with dose rate is found and attributed to competing evolutions of different defective structures.