Low-temperature solubility of copper in beryllium,in beryllium-aluminum,and in beryllium-silicon using ion beams

Ion implantation and ion backscattering analysis have been used to measure the solubility of copper in beryllium over the temperature range 593 to 1023 K, and to determine the effect on the copper solubility of aluminum and silicon impurities. The binary data extend 280 K lower in temperature than previous results, while the ternary measurements are unique. This information is pertinent to the use of copper for solution strengthening of beryllium. Diffusion couples were formed by ion implantation of copper into singlecrystal beryllium at room temperature, followed where appropriate by implantation of aluminum or silicon. The samples were then annealed isothermally, and the time-evolution of the composition-vs-depth profile, determined by ion backscattering analysis, yielded the solubility of copper. Measurements at exceptionally low temperatures were facilitated by the short diffusion distances, ≅0.1 μm, and the use of neon irriadiation to accelerate diffusion. The resulting binary data for the solubilityC ₀ of copper in beryllium merge smoothly into previous results at higher temperatures. The combined data, covering the temperature range 593 to 1373 K, are well described byC ₀=(12.6 at. pct)·exp(−842 K/T). In the ternary regime, the effects of aluminum and silicon on the solubility of copper were found to be small.