Investigation of Miniaturized Tensile Test Specimens Manufactured by Casting

The mechanical properties of solder joints are critical for the reliability and performance of miniaturized electronic devices, as these joints provide both electrical connections and mechanical support. This study investigates the effect of specimen size on the mechanical properties of a lead-free solder alloy, Innolot, with an emphasis on microstructural differences and their impact on tensile behavior. Miniaturized and large tensile test specimens were prepared, characterized, and tested to simulate real-life application conditions. Microstructural analysis revealed that miniaturized specimens contained 1–2 large grains, whereas large specimens exhibited 5–7 smaller grains in the cross-section, respectively. Tensile tests showed that miniaturized specimens had significantly lower yield strength (32.1 % decrease) and ultimate tensile strength (6.94 % decrease) but higher elongation at break (23.28 % increase) compared to large specimens. The increased variability in mechanical properties observed in miniaturized specimens highlights the influence of grain orientation and size on deformation mechanisms. These findings suggest that joint-scale mechanical properties differ from those of bulk materials and that miniaturized specimens may better represent the conditions of solder joints in practical applications.