Thermo-mechanical creep of two solder alloys

Abstract

Thermo-mechanical creep behaviors of a new lead free solder alloy 80Sn10In9.5Bi0.5Ag and eutectic solder alloy 63Sn37Pb are investigated in this paper. By using specially designed thin strip specimens and a computer controlled 6-axis mini fatigue tester, a series of reliable and consistent creep data are obtained. The 80Sn10In9.5Bi0.5Ag solder alloy shows very attractive creep characteristics and may have potential applications in electronics packaging technology. On the other hand, a new unified viscoplastic constitutive model proposed by Qian and Liu (1997b) is introduced to predict the creep properties of eutectic solder alloy. An excellent agreement between experimental data and model predictions is achieved. It is also observed that the creep rupture time will be significantly overpredicted if only power law regime is considered.