Low Temperature Material Characterization of Lead-Free SAC Solder Alloy at High Strain Rate After Prolonged High Temperature Storage

During operations, handling, and storage in extreme environmental applications including aerospace, defense and automotive, the electronics may be exposed to high and low operating temperatures. In automotive underhood applications, the temperature can vary especially from −65 to +200 °C. Under prolonged storage, SnAgCu solder materials have been shown to continually evolve in the mechanical properties. New doped SAC solder alloys have recently been introduced with the addition of Ni, Co, Au, P, Ga, Cu and Sb to SAC solder alloy to increase the robustness under prolonged thermal exposure. High strain-rate data on SAC solder alloys after prolonged storage operating at low operating temperatures is not available in published literature. In this paper, materials characterization of SAC (SAC105 and SAC-Q) solder after prolonged storage at low operating temperatures (−65°C–0 °C) and at high strain rates (10–75 per sec) has been studied. The fabricated SAC leadfree solder specimens were isothermally aged up to 12 months at 50°C before testing. Anand Viscoplastic model has been used to compute 9 anand parameters from measured Tensile data to describe the material constitutive behavior. The computed 9 anand parameters were used to verify the accuracy of the Anand model. A good correlation was found between experimental data and Anand predicted data.