The use of simulation to examine the processes involved in the alignment of voids under the influence of 2-dimensional self-interstitial atom transport was considered. The effects of 1-dimensional self-interstitial atom transport had previously been investigated by using a similar method. Unlike the 1-dimensional self-interstitial atom results, in the case of 2-dimensional self-interstitial atom transport it was not difficult to simulate the formation of simple-cubic void lattices. The work was also extended in order to demonstrate the formation of perfect body-centered cubic and face-centered cubic void lattices. An important feature was that lattice formation took place some 100 times faster than was found experimentally. It was thought unlikely that this was due to the diluting effect of out-of-plane jumps. An alternative conclusion was that the 2-dimensional diffusing defect could not be a single interstitial, but was instead a larger interstitial defect such as a di-interstitial which was present in far lower concentrations. One result of the new approach was that void-swelling was largely unaffected by the defect responsible for void-lattice formation. This avoided the rapid swelling which might otherwise occur as void-lattices formed, and would conflict with the assumed association of void-swelling saturation and void-lattice formation. The association was thought to be controlled by a common factor, such as a high void density, than by any direct mechanism.

Simulations of the Effects of 2D Interstitial Diffusion on Void Lattice Formation during Irradiation. J.H.Evans: Philosophical Magazine, 2006, 86[2], 173-88