Creep properties of Sn-8Mass%Zn-3Mass%Bi lead-free alloy

The creep properties of Sn-8mass%Zn-3mass%Bi were investigated and compared with those of other lead-free solders and a Sn-Pb eutectic solder. The creep rupture time decreases with increasing the initial stress and the temperature. For high stresses, the linear relationships between the minimum strain rate and the applied stress were observed. The stress exponents were examined to be 9.3, 7, and 4 at 298 K, 348 K, and 398 K, respectively. For low stresses, the minimum creep rate becomes relatively fast, and the creep resistance diminishes. In this range, secondary creep reduces, and the tertiary creep predominates. The creep properties of Sn-8Zn-3Bi are similar to those of Sn-Ag alloys at high stresses and those of Sn-0.5Cu at low stresses