Effect of Zr Addition on Microstructure and Mechanical Properties of a Cast Cu60Fe40 Alloy

Cu-Fe alloys have drawn extensive attraction due to excellent multi-functional properties, including electrical, magnetic, and mechanical properties. However, the immiscible nature of Cu-Fe alloys results in heterogeneous microstructure and unexpected mechanical properties. In this study, a small amount of Zr was added to the cast Cu60Fe40 (wt%) alloy to suppress the liquid-liquid phase separation during solidification of the alloy. The microstructure and mechanical properties of the Zr-free and Zr-containing Cu-Fe alloy were investigated. It is found that the addition of Zr successfully inhibits the heterogeneous microstructural evolution caused by liquid-liquid phase separation, while the FeZr-rich precipitates form in the dual-phase microstructure. The FeZr-rich precipitates affect grain growth of the Zr-containing alloy through the Zener pinning effect, leading to extra grain boundary strengthening and precipitation hardening. The resulting microstructure of the Zr-containing alloy substantially enhances the strength of the alloy with a loss of ductility. The fractured surface reveals that microcracks are formed near the precipitates, which is associated with the reduced elongation of the Zr-containing alloy.

Automated summary

In this study, Zr was added to a cast Cu60Fe40 alloy to suppress liquid-liquid phase separation and improve the microstructure and mechanical properties. The addition of Zr successfully inhibits the phase separation, but leads to the formation of FeZr-rich precipitates, which enhances the strength and hardness of the alloy.