Effect of temperature on high fluence transition metal implants into polycrystalline aluminum

Polycrystalline aluminium was implanted with 150 keV titanium ions (Ti⁺), manganese ions (Mn⁺) and nickel ions (Ni⁺) at 100 and 623 K, with fluences ranging from 0.6 × 10¹⁷ to 1.1 × 10¹⁸ ions cm^-2. At the higher temperature the implanted elements penetrated to regions much deeper than the projected range, the largest effect being observed for the manganese implants. The low temperature implants did not introduce important diffusion effects, with the exception of the nickel implants at a fluence of 9 × 10¹⁷ ions cm^-2. In contrast, they led to higher concentrations of the transition metals. The measured depth distributions of the implanted species are discussed in terms of radiation-enhanced diffusion, radiation-induced segregation, sputtering and phase formation. In most cases the formation of the aluminium-richest transition metal-aluminium crystalline phase was observed. The production of the crystalline NiAl₃ and MnAl₆ phases by ion implantation at 100 K is reported here for the first time. These phases were previously found to be unstable under irradiation. Their formation is interpreted considering the depth distributions of damage and transition metals.