Enhancing the Creep Resistance of Sn-9.0Zn-0.5Al Lead-Free Solder Alloy by Small Additions of Sb Element

Abstract

The creep phenomenon is considered as one of the most important deformation mechanisms under working conditions. The present study has examined the microstructure and creep properties of Sn-9.0Zn-0.5Al solder alloy after adding a small amount of Antimony (Sb). Nominal compositions of Sb additions were chosen to be 0, 0.5, 1.0, and 1.5 wt.%. The minimum strain rate was reduced for the Sb containing solder alloy. The stress exponents, n, were found to be around 3.7 for all soldiers at 130˚C. The stress exponent increases as the temperature drops from 100˚C to 50˚C, except for the 1.0% Sb alloy, where n 5.3 - 6.1 at all the temperature range (T = 50˚C, 100˚C and 130˚C). The results reveal that the Sb-containing solder alloys have better creep resistance with greater ductility than the Sb-free alloy due to solid solution strengthening, and intermetallic compound SnSb particle hardening.