Aluminium. in its natural oxidised state has been implanted with various doses of 170 keV Kr+ ions up to a maximum 10(16) cm(-2). The resulting defect and implanted species profiles have been profiled using positron beam techniques and Rutherford back-scattering, and compared with Monte-Carlo (TRIM-98) calculations. In addition, the initial and as-implanted material was characterised for changes in microstructure and preferred orientation using X-ray diffraction and microscopy. The aluminium showed signs of appreciable oxidation, which remained unchanged on implantation. There was evidence for deep damage, beyond the cascade region of the implanted ions, and for low doses, an absence of Kr in the material. Both of these observations are consistent with the influence of pre-existing stress on the drift of interstitial and vacancy defects during implantation.