Sb,Bi和Fe对Cu-8P共晶合金熔点和组织的影响

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

采用NETZSCHDSC404型差示扫描量热仪(DSC)、扫描电子显微镜(SEM)等手段研究了添加元素Sb,Bi和Fe对Cu 8P共晶合金熔点和组织的影响。实验结果表明:Sb,Bi和Fe均能降低Cu 8P合金的熔点。一定量的Sb与Cu,P形成低熔点相,从而大幅降低了Cu 8P合金的熔点,使其熔点降低近200℃;加入少量Bi后,Bi与Cu在共晶团晶界上形成熔点为270℃左右的低熔点化合物,且Bi的加入明显细化Cu 8P合金共晶团,从而使Cu 8P合金的熔点降低;加入Fe能明显细化Cu 8P合金的共晶团,使层片间距由8μm减为2μm以下,并使共晶团由层片状向短棒状转变,虽然Fe与Cu形成熔点为806℃的高温相,但Fe的细化作用使得Cu 8P合金的熔点降低,但降低幅度不大。同时得出形成低熔点的化合物(相)和细化晶粒是降低合金熔点的有效途径。

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.