Evolution of microstructure and properties of Cu-12Fe alloys prepared by twin-roll strip casting

The Cu-12Fe alloy has attracted significant attention due to its excellent electrical conductivity and electromagnetic shielding capability, high strength, cost-effectiveness, and recyclability. In the present work, the Cu-12Fe alloy strip with the thickness of 2.4 mm was successfully produced by twin-roll strip casting. The microstructure and properties of the Cu-12Fe alloy was tailored by cold rolling and aging treatment. The tensile strength of the as-cast strip is approximately 328 MPa and its elongation is 25%. The Fe phase randomly dispersed in the matrix, and the average size of Fe-rich phase is 2 µm. Besides, enrichment of Fe phase is observed in the central layer of the strip, results in the formation of the “sandwich structure”. Moreover, the as-cast strip of Cu-12Fe was directly cold-rolled from 2.4 to 0.12 mm. The directly cold-rolled sample after aging at 450 °C for 16 h (Process I) shows excellent electrical conductivity of 69.5% IACS, the tensile strength and elongation are 513 MPa and 3.8%, the saturation magnetic flux density is 20.1 emu·g−1, and the coercive force is 25.2 Oe. In Process II, the as-cast strip firstly cold-rolled to 1.2 mm, then aged at 500 °C for 1.5 h, followed by cold rolling to 0.12 mm, finally aged at 450 °C for 16 h. The sample after Process II shows the electrical conductivity of 66.3% IACS, the tensile strength of 533 MPa, an elongation of 3.5%, saturation magnetic flux density of 21.4 emu·g−1, and the coercive force of 22.3 Oe.