Effect of cyclic fatigue damage accumulation on the elastic-plastic properties of SAC305 solders

This study examines the effect of cyclic damage on the constitutive response of Sn3.0Ag0.5Cu (SAC305) solder material. Cyclic damage is induced through isothermal, mechanical cycling tests at high strain rate and room temperature, using a modified lap-shear microscale specimen (180 µm wide solder joint). The elastic, plastic, and yield response of the cycled solder joints are measured as a function of increasing cyclic damage, across various strain amplitudes. Significant piece-to-piece variability is observed in the measurements. This variability is consistent with previously reported viscoplastic measurements. Previous studies on the microstructure of solder in the initial state [1] and subsequent microstructural evolution due to cyclic damage [2] are summarized here to provide insights into the measured properties.