Simulations of the effects of 1-d interstitial diffusion on void lattice formation during irradiation

Abstract

This paper describes the use of simulation techniques to examine some of the processes involved in the alignment of voids under the influence of one-dimensional self interstitial atom (1-d SIA) transport. The work follows the paper of Heinisch and Singh [1] on this topic but a different and simpler methodology is used. Besides repeating the scenarios studied by Heinisch and Singh, the effects of re-nucleation and the influence of vacancies have been introduced. One of the important processes that emerged from the results was the barrier to precise void alignment caused by the SIA-induced coalescence of aligned voids. This appears to prevent the formation of stable void lattices by any 1-d SIA transport mechanism, a point supported by the initial void alignment in the mechanism requiring swelling values well above those found experimentally. A full consideration of the void lattice phenomenon shows that the one-dimensional diffusion of self-interstitials central to the production bias model of irradiation damage cannot be the only mode of anisotropic diffusion available under irradiation.

Acknowledgements

The author thanks Vladimir Dubinko for his valuable suggestion regarding the vacancy question. Many useful discussions with the late Alan Foreman (1929–2001) during the early part of the void lattice simulation study are also acknowledged. This work was jointly funded by the United Kingdom Engineering and Physical Sciences Research Council and by EURATOM. The author thanks Dr Sergei Dudarev and Dr Ian Cook for their interest in this work.