Synergistic strengthening mechanism of Mg and Si on Cu-Fe alloys with high strength and high conductivity

In this study, high strength and conductivity Cu-Fe-Si-Mg alloys were produced by casting and multi-stage thermos-mechanical treatment (MTT). The electrical conductivity, yield strength, tensile strength and elongation of the Cu-2.5Fe-0.1Si-0.15 Mg alloys were 68.23 %IACS, 653 MPa, 692 MPa and 4.35 %, respectively. The addition of Mg was beneficial to reduce the generalized planar fault energy and increase the density of substructure. Meanwhile, there was a tendency for Mg atoms to segregate at the interfacial region where the second phase met the copper. The segregation of Mg effectively inhibited the growth of precipitates. There was a dramatic improvement in the ability of the second phase to pin dislocations. The overall properties of the Cu-Fe alloys were excellent. The synergistic addition of Mg and Si significantly improved the mechanical properties of the alloys, but the electrical conductivity slightly declined.