Effects of Cu and Sb Addition on Properties of Sn-Bi Eutectic Alloys

Abstract:

In this paper, fusible alloy with rated temperature of 142℃ were designed by add Cu and Sb element 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 long Cu₆Sn₅ and Cu₃Sn phases were formed in the alloy matrix. These second phases strengthened the tensile strength of the alloy, but reduced the plasticity of the alloy. The strength of (Sn58Bi)3Cu3Sb fusible alloy is 85.4 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