Abstract
This paper describes low cycle fatigue (LCF) lives of Sn-37Pb and Sn-3.5Ag solders at lower temperatures. Push-Pull LCF test were carried out at 253K and 273K to examine the effect of temperature on fatigue life. Tension stress increased with decreasing temperature for Sn-37Pb. There was a slight effect of temperature on tension stress for Sn-3.5Ag. Plastic strain range was a suitable parameter for correlate the LCF lives. All of the data correlated with plastic strain range within a factor of 2 band based on the 313K data independent of temperature for Sn-37Pb. Plastic strain gave a proper life prediction, within a factor of 2 for Sn-37Pb, but gave an unconservative prediction for Sn-3.5Ag data at a lower temperature. Main cracks propagated in the principal strain direction for both solders.
