Gold implanted into aluminium: Concentration dependence of the subsitutional component and phase transition

High substitutional fractions, f s, with values up to 0.87 were measured for Au implanted into Al single crystals at 77 K with peak concentrations up to 5 at.%. This solubility limit exceeds that observed for 293 K implants by one order of magnitude. At higher Au concentrations a transformation takes place most probably into an amorphous phase. Annealing the 77K implants at 293 K leads to a decrease in f s. Postirradiation experiments with 300 KeV He and Ar ions at 77 K suggest that the decrease of f s upon annealing is maily due to Au precipitate formation.