Phase equilibria in the Al-rich region of Al–Cu–Ir

The Al–Cu–Ir alloy system was studied in the compositional region above 30 at.% Al from 1100 to 540 °C. Of the Al–Ir binaries, the β-AlIr, C-Al2.7Ir, Al3Ir, χ-Al28Ir9, φ-Al45Ir13 and Al9Ir2 phases dissolve up to 35, 13, 8.5, 4, 3 and 2.5 at.% Cu, respectively. The solubility of Ir in the Al–Cu η1 (η2), 1 (2) and θ phases is below 1 at.%, while the γ0 dissolves up to 4.5 at.% Ir. The equilibria involve four previously reported ternary phases ω, C2, ɛ and D1 forming around Al70Cu20Ir10, Al63Cu13Ir24, Al72Cu9Ir19 and Al60Cu24Ir16, respectively, and a new Al2CuIr phase revealed inside the β-phase range below 1063 °C. Partial isothermal sections were determined at 1100, 1000, 980, 900, 800, 700, 600 and 540 °C.