Effect of strain rate and temperature on the tensile properties of tin-based lead-free solder alloys

The tensile properties of Sn-3Ag-0.5Cu, Sn-3.5Ag, and Sn-0.7Cu lead-free solders were investigated on small-scale specimens and compared with those of Sn-37Pb eutectic solder at various strain rates from 1 x 10(-4) s(-1) to 1 x 10(-2) s(-1) and over a wide temperature range from 25 degrees C to 150 degrees C. The tests were under true strain-rate-controlled conditions. The ductility of each lead-free solder is relatively constant while that for Sn-Pb eutectic solder strongly depends on strain rate and temperature. The strain rate sensitivity index m for lead-free solders is relatively stable and showed little dependence on temperature, whereas the values of m for Sn-37Pb increased linearly with increasing temperature.