SnBi/Cu焊接接头的剪切性能及界面微观组织分析

通过对断口形貌和界面微观组织的观察分析,研究了3种Sn-Bi/Cu焊接接头的剪切断裂机理.结果表明:3种Sn-Bi/Cu焊接接头均在弹性变形阶段断裂,并且均沿Sn-Bi焊料/Cu基板界面处断裂.孔洞降低了3种Sn-Bi/Cu焊接接头的有效连接面积,从而降低了其剪切强度.根据3种Sn-Bi/Cu焊接接头断口形貌,Sn59.9Bi40Cu 0.1/Cu和Sn57.9Bi40Zn2Cu 0.1/Cu焊接接头剪切断裂机制属于准解理、沿晶脆性断裂和韧窝的混合型断裂,而Sn42Bi58/Cu焊接接头剪切断裂机制属于准解理断裂.微观组织分析显示,3种焊料合金焊接接头界面处的金属间化合物层均为连续的Cu₆Sn₅相.

Analysis of Shear Property and Interfacial Intermetallic Compounds of Sn-Bi/Cu Solder Joints

The shear facture mechanism of Sn-Bi/Cu solder joints were studied by analyzing the fracture morphology and interfacial intermetallic compounds(IMCs).The result showed that all the three Sn-Bi/Cu solder joints almost ruptured at the elasticity deformation phase and the fractures occurred at the interface of Sn-Bi solder and Cu substrates.In addition,the shear strengths of the three Sn-Bi/Cu solder joints were decreased,since the real contact areas of the solder joints were reduced by the voids.According to the fracture morphology of the three Sn-Bi/Cu solder joints,the fracture mechanisms of Sn59.9Bi40Cu0.1/Cu and Sn57.9Bi40Zn2Cu0.1/Cu solder joints were the mixture of quasi-cleavage,intergranular brittle and dimple,while the fracture mechanism of Sn42Bi58/Cu solder joint was quasi-cleavage.The microstructure analysis results showed that the IMCs of the three Sn-Bi/Cu solder joints were all continuous Cu₆Sn₅ phase.