Microstructures and shear properties of antimony- and indium-strengthened Sn5Bi/Cu joints

• Published in: Advanced composites and hybrid materials Vol. 7; no. 3
• Main Authors: Zhang, Jiaheng, Zhao, Yongheng, Wang, Xiaojing, Cai, Shanshan, Peng, Jubo, Liu, Chen, Kallel, Mohamed, El-Bahy, Zeinhom M., Wang, Shuai, Liu, Baosheng, Zhang, Weibin, Chen, Cai, Guo, Fengyi, Wang, Yingwu, El-Bahy, Salah M.
• Format: Journal Article
• Language: English
• Published: Cham Springer International Publishing 01.06.2024
• Subjects: Ceramics; Chemistry and Materials Science; Composites; Glass; Materials Engineering; Materials Science; Natural Materials; Polymer Sciences; Fracture; Tin solders; Solution strengthening; Shear property; Phase diagram
• ISSN: 2522-0128; 2522-0136
• DOI: 10.1007/s42114-024-00889-4

The effects of Sb/In (with a loading x of 1, 2, 3 wt.%) in the Sn5Bi solder alloy on the melting properties, microstructures, and the shear behavior of solder/Cu joints were investigated combined with the corresponding phase diagram. It is found that the addition of Sb reduces the melting range and supercooling with the increase of Sb content caused by SbSn formation, while the In addition can reduce the melting point resulted by In solid solution. Both Sn5Bi x In/Cu and Sn5Bi x Sb/Cu are mainly composed of β-Sn and two types of precipitates, i.e., Bi particles and Cu 6 Sn 5 compound. The difference lies in that In doping only can dissolve into β-Sn and Cu 6 Sn 5 while Sb doping mainly forms tiny SbSn. Increasing In content also inhibits the precipitation of Bi particles and reduces the phase fraction Cu 6 (Sn, In) 5 , resulting in that precipitation strengthening becomes weaker and solid solution strengthening becomes stronger. In contrast, the phase fraction of Bi particles and Cu 6 Sn 5 increases with increasing the Sb content, leading to the stronger precipitation strengthening. These strengthening mechanisms cause their ultimate shear force to monotonically increase with increasing Sb and In content, and the strengthening effect of the Sb element is better. Sb and In addition also can improve the ductility of Sn5Bi/Cu solder joints, and both 2 wt.% In/Sb additions present the best shear fracture work. Thus, the optimal mechanical property was achieved by 2 wt.% Sb addition. These reinforcements will provide a strong support and specific data reference for the interconnection requirements in high-strength interconnection fields such as automotive electronics, power semiconductor, and medical electronic products. Graphical abstract