Effect of strain rate on fatigue of low-tin lead-base solder

Fatigue of low-tin lead-base solder was studied at different strain rates. The effect of tensile hold time (low strain rate) in reducing the number of cycles to failure was found to be much more dramatic than the effect of ramp time (higher strain rate). While increasing up to 1 h time per cycle for no-hold tests did not lead to fatigue life saturation, an increase in tensile hold time over a few minutes led to saturation in the number of cycles to failure. Differences in effects of hold and ramp were attributed to different mechanisms of solder fatigue fracture. It is concluded that fatigue life prediction of solder should be based on tests involving hold time.<
>