Dynamic Behavior Tests of Lead-free Solders at High Strain Rates by the SHPB Technique

Dynamic behavior of solder joints in microelectronic packages is key issue for drop/impact reliability design of mobile electronic products. The dynamic mechanical behaviors of 63Sn37Pb, 96.5Sn3.5Ag and 96.5Sn3.0Ag0.5Cu solder alloys at high strain rate were investigated by using the split Hopkinson pressure/tension bar testing technique. Stress-strain curves of the three materials were obtained at strain rate 600 s(-1), 1200 s(-1) and 2200 s(-1), respectively. The experimental results show that all the three materials are strongly strain rate dependent. Among them 96.5Sn3.5Ag is the most sensitive to strain rate, while 96.5Sn3.0Ag0.5Cu has the greatest yield stress and tensile strength. Relations of the tensile strength, fracture strain and yield stress of the materials with strain rate were proposed by fitting the experimental data.