熔炼了Sn-3.5Ag、Sn-1.6Cu、Sn-Zn-0.7Cu、Sn-8Zn-3Bi等4种低熔点（低于230℃）合金，根据这4种合金在T2铜基板上的铺展面积确定出铺展效果较好的合金，并分析了该合金与铜基板的界面结合情况。结果表明：Sn-1.6Cu合金在T2铜基板上的铺展性能最好，其铺展面积最大，且铺展后的表面光滑，Sn-3.5Ag合金的铺展性能次之，Sn-Zn-0.7Cu合金和Sn-8Zn-3Bi合金的铺展性能较差；Sn-1.6Cu合金在铜基板上铺展后，其连接界面无气孔、裂纹等缺陷，界面处发生了元素互扩散，形成了铜锡固溶层，界面结合性能良好。

Four low-melting-point (below 230℃) alloys, including Sn-3.5Ag, Sn-1.6Cu, Sn-Zn-0.7Cu, Sn-8Zn-3Bi, were smelted. On the basis of spreading areas of the four alloys on T2 copper substrate, the alloy having relatively good spreading effects was determined, and then the interface bonding property of the alloy with the copper substrate was analyzed. The results show that the Sn-1.6Cu alloy had the best spreading performance on T2 copper substrate, with the largest spreading area and a smooth spreading surface. The spreading performance of the Sn-3.5Ag took second place, and that of the Sn-Zn-0.7Cu alloy and Sn-8Zn-3Bi alloy was relatively poor. After the Sn-1.6Cu alloy was spread on the copper substrate, no defects such as pores and cracks at the interface were observed, and inter-diffusion of elements occurred at the interface, forming a copper-tin solid solution layer; the interface bonding property was good.