Phase Diagrams

· The κ (Al) phase is a solid solution of copper in an aluminum matrix, and at the eutectic temperature (548 C) can have a maximum copper content of 5.65 wt % copper.
· The CuAl₂ (θ) phase is an inter-metallic compound. The width of this region indicates that the compound is stable over a small range about the stoichiometric composition of
Al- 53.5 wt % Cu.

From: Van Vlack,
"Elements of Materials Science and Engineering,"
Addison Wesley (1989)

· At the eutectic temperature (548 C) the θ phase has the composition
Al - 52.5 wt % Cu. Liquid in equilibrium with θ and κ has the composition:
Al - 33.2 wt % Cu.