Cu和Sb元素添加对Sn-Bi共晶合金性能的影响

向Sn-Bi共晶合金中同时添加Cu和Sb元素设计额定温度为142℃的易熔合金,并对合金的熔点、相组成、准静态拉伸性能、焊接接头力学性能进行了研究。结果表明,Cu与Sb元素的添加使合金的熔点上升,但是合金的过冷度和熔化潜热下降。添加Cu和Sb元素后,在合金基体内形成了块状的SnSb相和长条状的Cu₆Sn₅、Cu₃Sn相,这些第二相强化了合金的抗拉强度,但降低了合金的塑性。(Sn58Bi)3Cu3Sb易熔合金抗拉强度为86.4 MPa,塑性为15.5%,熔点为141.8℃,其与覆铜板焊接接头的抗剪切强度较Sn-Bi共晶合金明显提高,可达到55.7 MPa。

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

Fusible alloy with rated temperature of 142 °C 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(Sn58 Bi)3 Cu3Sb fusible alloy is 86.4 MPa, the plasticity is 15.5%, and the melting point is 141.8 °C. 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.