Molecular Dynamics and OKMC Study of Radiation Induced Motion of Voids and He Bubbles in BCC Iron

TL;DR

This study combines molecular dynamics and OKMC simulations to demonstrate radiation-induced movement of voids and helium bubbles in BCC iron, revealing significant enhancement of void diffusion and the damping effect of helium.

Contribution

It introduces a combined MD and OKMC approach to quantify radiation-induced void and bubble motion in BCC iron, highlighting the impact of helium presence.

Findings

Void movement can be induced by radiation cascades in iron.

Void diffusion is enhanced by two orders of magnitude due to radiation.

Helium dampens the movement of helium bubbles.

Abstract

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. The effect of this mechanism is studied further using an OKMC code and shows enhancement of void diffusion by 2 orders of magnitude from 1x10^-22 cm^2/s to 3x10^-20 cm^2/s. Repeating the study on He bubbles shows that the movement is damped by the presence of helium in the void.