The ternary Al–Ce–Cu phase diagram in the aluminum-rich corner

The phase diagram of the Al–Ce–Cu system in the aluminum-rich corner (concentrations up to 35 wt.% Cu and up to 16 wt.% Ce) was studied. Phases and invariant reactions were identified. Liquidus and solidus surfaces, three isothermal cross-sections (540, 590 and 200 °C) and five vertical cross-sections were constructed. It was shown that Al4Ce (Al11Ce3), Al8CeCu4 and Al2Cu were in equilibrium with the aluminum solid solution (Al). It was determined that about 17 wt.% Cu dissolves in Al4Ce; the existence of the Al4CeCu phase was not confirmed. Experimentally determined parameters of the invariant quasi-binary eutectic reaction L → (Al) + Al8CeCu4 (610 °C, 14 wt.% Cu and 7 wt.% Ce) were essentially different from those published earlier. This eutectic had a fine microstructure and was stable to coarsening (after fragmentation and spheroidizing) during the heating process even though the average particle size did not grow larger than 2 μm after annealing at 590 °C.