Molecular dynamics and object kinetic Monte Carlo study of radiation-induced motion of voids and He bubbles in bcc iron

We show that voids adjacent to radiation damage cascades can be moved in their entirety by several lattice spacings. This is done using molecular dynamics cascade simulations in iron at energies of 1-5 keV. An equation describing this process is added to an an object kinetic Monte Carlo (OKMC) code to allow study of the mechanism at longer time scales. The mechanism produces an enhancement of void diffusion by two orders of magnitude from 1 x 10(-22) cm(2)/s to 3 x 10(-20) cm(2)/s. Repeating the study on He bubbles shows that the movement is damped by the presence of helium in the void. DOI: 10.1103/PhysRevB.87.104106