YTTRIUM ION-IMPLANTATION IN PURE ALUMINUM

The penetration depth of yttrium ions extracted at 30 kV from a metal vapor vaccum arc source reaches about 150 nm in pure aluminum; the max imum retained concentration is 20-50 at.% for varying doses of 5 x 10( 16) to 1 x 10(18) cm-2. Upon post-annealing at 600-degrees-C, the impl antation-induced YAl3 (rhombohedral Bravais lattice with 12 atoms per unit cell) transforms in part into YAl3 (hexagonal Bravais lattice wit h eight atoms per unit cell); yttrium diffuses deep into the bulk alum inum (600 nm) with a diffusion coefficient of 3.56 x 10(-13) cm2 s-1; the directive diffusion and incorporation of foreign iron atoms result in the production of YFe3.5Alx (x < 17). No transition phase is obser ved at the precipitate-aluminum interfaces.