Micro-Mechanics of Creep-Fatigue Damage in Pb-Sn Solder Due to Thermal Cycling

This paper presents a micro-mechanistic approach for modeling fatigue damage initiation due to cyclic creep in eutectic Pb-Sn solder. Damage mechanics due to cyclic creep is modeled with void nucleation, void growth and void coalescence model based on micro-structural stress fields. Micro-structural stress states are estimated under viscoplastic phenomena like grain boundary sliding and its blocking at 2^nd phase particles, and diffusional creep relaxation. A conceptual framework is provided to quantify the creep-fatigue damage due to thermo-mechanical cycling. Some parametric studies are provided to better illustrate the utility of the developed model.