Multilayered phase formation after high-fluence implantation of nickel into aluminium

The formation of crystalline and amorphous layers has been observed in Al c rystals after 5 MeV Ni implantation up to a fluence of 7.6x10(17) Ni atoms cm(-2). The layers are structured into sublayers perpendicular to the impla ntation direction with sharp interfaces between the phases and almost symme trically arranged to both sides of the maximum of the implantation profile. The sublayers of thickness of the order of 100 nm were analysed by transmi ssion electron microscopy. They consist of polycrystalline Al3Ni, crystalli ne Al3Ni precipitates and small amorphous zones, depending on the local Ni implantation concentration.