Formation of Al2Cu and AlCu intermetallics in Al(Cu) alloy matrix composites by reaction sintering

We report the fabrication and characterization of a series of Al(Cu) alloy-based matrix composites. The composites were produced by sintering and rapid quenching three powder mixtures of Al and Cu with hypoeutectic, eutectic, and hypereutectic compositions. The morphology of the reinforcements formed in the Al(Cu) matrices of these composites was found to be variable. A two-phase Al2Cu–Al(Cu) nanoeutectic, with lamellar spacing of 200–300 nm, was found in the Al(Cu) matrix of the sample having hypoeutectic composition after it was oil-quenched from 1000 °C to room temperature. While oil quenching the sample with eutectic composition, produced single Al2Cu crystals of 2–2.5 μm size, embedded in a lamellar nanoeutectic matrix. As for the hypereutectic alloy, the matrix of the oil-quenched sample consisted mainly of Al2Cu intermetallic, and a secondary phase of AlCu dendrites with dendrite arms spacing of 1–1.5 μm.