Cavity mediated strain localization and overall ductility in eutectic tin-lead alloy

A combined experimental and numerical study is undertaken to examine the effects of pre-machined holes on strain localization and overall ductility in eutectic tin-lead alloy. Thin-sheet specimens with equal-sized holes aligned in the tensile loading direction are used. The tensile tests were performed at room temperature with a nominal strain rate of 0.001 s−1. The specimen, containing one hole, showed a significant reduction in ductility compared to the control (no-hole) specimen. With an increasing number of holes, however, the overall strain-to-failure increases and fracture tend to follow shear bands generated locally from the hole edges. Finite element analyses, taking into account the viscoplastic response, were carried out to provide a mechanistic rationale to corroborate the experimental findings. The dispersion of plastic deformation and the effect of hole interaction are both found to contribute to the observed behavior. The local maximum equivalent plastic strain decreases with increasing number of holes, resulting in more delayed fracture. Plastic deformation becomes more intense inside the shear band when the holes are spaced more closely, which explains the increasing propensity of fracture along the shear bands in specimens containing more pre-machined holes.