Discontinuous plasticity in Sn single crystals: a combined experiment and modelling study

Discontinuous plastic flow (DPF) in single-crystal tin (Sn) is investigated through a combined rate-dependent discrete dislocation plasticity (DDP) framework and micropillar compression experiments. The observed stress oscillations are attributed to the thermally activated pinning-depinning dynamics of dislocations interacting with obstacles. The magnitude of these serrations shows a clear dependence on crystallographic orientation, which stems from the variation in thermal activation behavior across different slip systems. By calibrating the thermal activation parameters in the DDP model, the creep behavior of Sn single crystals is quantitatively predicted. A correlation is established between the secondary creep rate and the amplitude of stress oscillations measured in micropillar tests. This study thus offers a physics-based pathway-independently verified-to predict slip-dominated creep rates from small-scale mechanical testing, bridging microstructural features with long-term mechanical performance, and yielding critical insights into the reliability of solder joints.