This work addresses the microstructures and mechanical properties of Al-4.5 wt% Cu alloys containing 0.1, 0.2 and 0.4 wt% Sc that were solidified under low cooling rate conditions (< 1ºC/s) and then heat treated. The samples were solidified in a differential scanning calorimeter before being heat treated using two different approaches. The first approach, the traditional sequences of heat treatment, consisted in solutionizing at a constant temperature followed by quenching and aging. The second

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... approach consisted of direct aging of the as-solidified samples. Sc was neither a grain refiner nor a strengthener in the as-solidified conditions. Instead it modified the grain morphology from elongated dendrites to equiaxed structures. While the two heat treatment approaches yielded no significant difference on these slowly solidified Sc containing samples, the resulting mechanical properties are found to be positively affected, provided that much of the Sc is dissolved in the matrix during solidification.