Abstract
Thin aluminium foils have been implanted, primarily with argon ions but also with other inert gases. In the as implanted condition and after annealing to a series of temperatures, the clustering of the inert gases to form bubbles and the subsequent bubble growth have been studied by analytical electron microscopy. The consecutive use of transmission electron microscopy with X-ray analysis and electron diffraction has enabled measurements of the proportion of gas located in the visible bubble population and the gas density within bubbles. The information obtained using these techniques has indicated that sub-microscopic argon bubbles are immobile and may remain so up to temperatures as high as 500°C. Together with this observation it is shown that there is a considerable delay in achieving the equilibrium thermal vacancy concentration. It has also been found that at temperatures close to the melting point gas resolution will cause a net loss of gas from bubbles to the metal/oxide interface at the foil surface. During ion implantations at elevated temperatures it was observed that precipitates, later found to be oxides, were associated with bubbles. This led to the realisation that oxygen would be knocked-in from the surface oxide during all ion implantation experiments. Further experiments were carried out to assess the effects of a surface oxide on inert gas bubble behaviour. Amongst other effects the oxide will slow down bubble growth by migration and coalescence as it will inhibit diffusion at the bubble surface.