Dynamic strength and strain rate sensitivity of 37 wt% Pb 63 wt% Sn eutectic solders

An experimental investigation into the dynamic strength and strain rate sensitivity of 37 wt% Pb-63 wt% Sn superplastic alloy was carried out. Tests were conducted at room temperature and under both uniaxial compression and tensile conditions. The nominal strain rates were varied by seven orders of magnitude, from 10-4 to 103 s -1. Specimens from two different heat treatments (or phase sizes) were tested, as coarsening is one of the main reasons for failure of solder joints. It is found the materials' dynamic yield stress largely falls into a linear relation to the strain rate in logarithm scales. Phenomenological constitutive relations were then established following Cowper-Symonds model