| Abstrakt: |
The constitution of the Ni-Al-Ru system has been investigated in the range 0 to ~50 at% Al. Isothermal sections at 1523 and 1273 K have been determined using microstructural observations, electron probe microanalysis and X-ray diffraction. The phases present were: nickel-based solid solution (?); ?' (based on Ni3Al); solid solutions based on NiAl and RuAl, respectively (designated ß1 and ß2), and ruthenium-based solid solution (Ru). The maximum solubility of Ru in ?' was ~5 at%. ß1, and ß2 show extensive range of solubilities, namely up to ~20at% Ru in ß1 and up to ~25 to 35 at% Ni in ß2. Three-phase equilibrium between ?, ß2 and (Ru) existed at 1523 and 1273 K. Also at 1523 K, three-phase equilibria existed between ?, ?' and ?1 and ?,ß1 and ?2, while at 1273 K, the equilibria were between ?', ?1,?2 and ?, ?', ß2 indicating the occurrence of a reaction ?+ß1, ? ?' +ß2 at a temperature between 1523 and 1273 K. Liquidus features have been deduced from data on as-solidified structures. Lattice parameter data and hardnesses are also reported. |
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