Effect of Carbon on the Microstructure of a Cu-Fe Alloy

The effect of C addition on the microstructure of a Cu-Fe alloy was investigated by combining the calculation of phase diagram (calphad) and the experimental research. The calphad results indicated that the addition of C substantially enlarged the zone of liquid immiscibility gap in the metastable phase diagram of Cu-Fe alloy. In addition, the larger the addition content of C was, the more obvious the phenomenon was. As a result, the presence of trace amounts of C in the Cu-Fe alloy containing 5~20% (wt.) Fe would cause the liquid phase separation of Cu-rich and Fe-rich liquid phases during the solidification process of the alloy. The experimental results showed that the dendritic secondary phase in the as-cast microstructure of the Cu-14Fe alloy tended to be spheroidized after the addition of C due to the separation of Cu-rich and Fe-rich liquid phases. With the increasing content of C, the volume fraction and the average diameter of the spherical Fe-rich particles both increased. The calphad conclusions are in agreement with the experimental results.