Effect of multi-stage thermomechanical treatment on Fe phase evolution and properties of Cu-6.5Fe-0.3Mg alloy

Abstract

The effect of hot rolling on the evolution of Fe phase and the properties of Cu-6.5Fe-0.3 Mg alloy is explored. The results show that the optimal performance (i.e. ultimate tensile strength (818 MPa), electrical conductivity (61.7%IACS), and electromagnetic shielding (85–100 dB)) was obtained by hot rolling + cold rolling + heat treatment. It was found that the tadpole-like Fe phase in the Cu-6.5Fe-0.3 Mg alloy after primary hot rolling was smaller and denser than those after primary cold rolling, which is attributed to the hot grooving and splitting behavior of the Fe phase during hot rolling. The depth of thermal slotting of the Fe phase increases with the increasing of the heat treatment temperature. After large plastic deformation, the tadpole-like Fe phases transforms into Fe fibers and its density is higher. The strengthening method of Cu-6.5Fe-0.3 Mg alloy is fiber reinforcement and its electromagnetic shielding performance increases with the density of Fe fibers. The splitting of the Fe phase during hot rolling significantly increases the density of Fe fiber, thereby improving its tensile strength and electromagnetic shielding performance. This work will provide a new guideline for the preparation of high-performance Cu-Fe-Mg alloys. • During the hot rolling, the Fe phase undergoes hot grooving and splitting behavior. • Hot rolling increases the density of Fe particles and Fe fibers. • The addition of Mg element improves the thermal stability of the Fe phase. • Hot rolling + cold rolling improves the tensile strength of Cu-6.5Fe-0.3 Mg alloy. • Hot rolling + cold rolling improves the electromagnetic shielding performance of Cu-6.5Fe-0.3 Mg alloy.