Phase equilibria in the Be--Al--Fe system using high-energy ion beams. II

Ion beam methods have been used in a study of the beryllium rich region of the beryl-lium-aluminum-iron phase diagram. Tailored alloys formed by ion-implanting aluminum and iron into beryllium were annealed, and their evolution with time was followed by ion backscattering analysis. In this way, the maximum and minimum aluminum to iron atomic ratios in the ternary phase of nominal composition AlFeBe4 were determined in the temperature range 773 to 1073 K; these ratios are 1.4 ±0.1 and 0.93 ±0.15, respec-tively, with any temperature dependence being less than the experimental uncertainty. In addition, the solubilities of aluminum and iron in beryllium were measured for the three-phase condition where α-Be, AlFeBe4, and FeBe11 coexist. When combined with previous ion beam results for the boundaries about the α-Be phase on the phase diagram, these data provide a detailed picture of the beryllium-rich region of the beryllium-aluminum-iron phase diagram.