Derivation of dynamic constitutive equation of lead-free solder and clarification of impact characteristics of area-array pac

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In order to investigate the tensile characteristis of lead-free solder at high strain rates, impact tensile test equipment far solder Vials was developed, on the basis bf the direct tension split Hopkinson bar technique. By using this equipment,.tensile stress-strain characteristics data of the Sn-3.0Ag-0.5Cu lead-free solder and the Sn-Pb conventional solder up to fracture were measured with a high accuracy at strain rate of 1.66 x 103 and compared with those at quasi-static strain rates of 1.2 and 1.2×10^<-2>. The results show that the proof. stress and tensile strength of the Sn-3.0Ag-0.5 Cu lead-free solder increase significantly with ending strain rate comparing with the Sn-Pb conventional solder. It is also shown that the fracture morphology of Sn 3.0Ag-0.5Cu solder changes from ductile fracture to brittle fracture with increase in the strain rates