中国有色金属学报(英文版)
Transactions of Nonferrous Metals Society of China
| Vol. 32 No. 10 October 2022 |
（1. Department of Industrial Engineering, Faculty of Engineering, Rajamangala Unversity of Technology Srivijaya, 90000 Songkhla, Thailand;
2. Division of Physical Science, Faculty of Science, Prince of Songkla University, Hat Yai, 90110 Songkhla, Thailand）
Abstract:This research investigated the combined effects of addition of Bi and Sb elements on the microstructure, thermal properties, ultimate tensile strength, ductility, and hardness of Sn-0.7Ag-0.5Cu (SAC0705) solder alloys. The results indicated that the addition of Bi and Sb significantly reduced the undercooling of solders, refined the β-Sn phase and extended the eutectic areas of the solders. Moreover, the formation of SbSn and Bi phases in the solder matrix affected the mechanical properties of the solder. With the addition of 3 wt.% Bi and 3 wt.% Sb, the ultimate tensile strength and hardness of the SAC0705 base alloy increased from 31.26 MPa and 15.07 HV to 63.15 MPa and 23.68 HV, respectively. Ductility decreased due to grain boundary strengthening, solid solution strengthening, and precipitation strengthening effects, and the change in the fracture mechanism of the solder alloys.
Key words: Sn-0.7Ag-0.5Cu solder alloys; intermetallic compounds; strengthening mechanism; undercooling; mechanical properties
