Effect of Sb, Bi and Fe on melting points and microstructures of eutectic Cu-8P alloys

The effect of Sb, Bi and Fe on the melting points and microstructures of Cu-8P alloys were studied by means of DSC and SEM. It is found that the addition of Sb, Bi and Fe can decrease the melting points of Cu-8P eutectic alloy. Sb can combine with Cu and P to form a low melting point compound which lowers the melting point of binary Cu-8P eutectic alloy by nearly 200 ℃. Bi and Cu can create compounds with low melting point(270 ℃) distributing at the boundaries and that is the reason why the melting point of (Cu-8P)-Bi is lower than that of binary Cu-8P eutectic alloy. The eutectic cluster can be refined with the addition of Fe, and that is the reason why the addition of Fe can decrease the melting point of Cu-8P alloy. Two means of decreasing the melting point of Cu-8P are found. One is to form compound with low melting point, the other is to refine the eutectic cluster.