Cu和Sb元素添加对Sn-Bi共晶合金性能的影响

Fusible alloy with rated temperature of 142℃ was designed by adding Cu and Sb elements into Sn-Bi eutectic alloy. Besides, the melting temperature, phase composition, quasi-static tensile properties and mechanical properties of solder joints were studied. The results show that the addition of Cu and Sb increases the melting point of the alloy, but the subcooling and latent heat of melting of the alloy decrease. After adding Cu and Sb elements, a bulk SnSb phase and rod-like Cu₆Sn₅ and Cu₃Sn phases form in the alloy matrix. These second phases strengthen the tensile strength of the alloy, but reduce the plasticity of the alloy. The tensile strength of (Sn58Bi)3Cu3Sb fusible alloy is 86.4 MPa, the plasticity is 15.5%, and the melting point is 141.8℃. The shear strength of the welded joint with copper clad plate is significantly higher than that of Sn-Bi eutectic alloy, which can reach 55.7 MPa.