An investigation of the Al-rich region of the Al–Ni–Ir phase diagram

The Al–Ni–Ir alloy system was studied in the range of above 50 at.% Al. Partial 1150, 1000, 900 and 800 °C isothermal sections were determined. Congruent equiatomic AlIr and AlNi phases form a continuous region of solid solutions. The C–Al2.7Ir, χ-Al28Ir9 and Al9Ir2 phases dissolve up to 7, 10.5 and 2.5 at.% Ni, respectively. Increasing the Ni concentration results in a slight decrease of the Al concentration of these phases. The Al3Ni2 phase dissolves up to 2.5 at.% Ir, while the solubility of Ir in Al3Ni is 1 at.%. A ternary orthorhombic ɛ6-phase (a = 2.34 nm, b = 1.65 nm, c = 1.24 nm) was found below 1342 °C in a compositional range extending from Al73Ni4Ir23 to Al72Ni17.5Ir10.5.