[en] Carefully prepared samples of (11 3 1) oriented Cu single crystals were bombarded with 40 keV ions to fluences of the order of 10¹⁹cm^-2. The ion species chosen were Ne, Ar, Kr, Xe, N and Cu, and thus represented a range of light to heavy, chemically inert species, a more chemically active species and the self ion species. Post-irradiation observation was performed by scanning electron microscopy at Copenhagen and subsequently at Salford. The results are explained in terms of preferential sputtering of native and irradiation induced defect structures and differential atomic mobility of different ion species in the Cu. The Cu⁺ irradiation results exhibit the lack of necessity of occluded gas for feature development whilst the N⁺ results indicate that, for Cu, improved impurity depth profiling accuracy by sputter sectioning with such a chemically active species is unlikely. (author)