Mechanical Tensile Behaviors of Sn-Bi Lead-Free Solder Alloys Under Different Strain Rates and Temperatures

This study focuses on analyzing two types of low-carbon solder balls: 58.8Sn-40Bi-l.0Ag-0.2Cu and 59.47Sn-40Bi-0.5Cu-0.03Ni. Tensile tests were conducted to examine their mechanical properties at different strain rates (2E-4/s, 2E-5/s, 2E-6/s) and temperatures (25°C, 75°C, 115°C). The results show that the ultimate strength of the 58.8Sn-40Bi-1.0Ag-0.2Cu solder at 25°C is 73.7 MPa, which is an increase of 103% compared to the traditional SAC305 solder. Furthermore, variations in strain rate significantly affect the material's yield strength and Young's modulus, indicating that the reliability of the material will be enhanced under high-strength mechanical behavior, with a maximum increase of 63%. However, in high-temperature environments, the maximum decrease in strength is 78%.