Radiation-Induced Interfacial Degradation and Mechanical Reliability of Sn-Based Solder Joints: A Systematic Review

Solder joints in aerospace, nuclear, and defense electronics are increasingly exposed to ionizing radiation, which creates serious reliability issues. Despite its importance, a comprehensive understanding of the underlying mechanisms and how they vary across radiation types remains lacking. This systematic literature review synthesizes 24 peer-reviewed studies (2000-2025) to evaluate radiation-induced microstructural evolution and mechanical degradation in Sn-based solder alloys. Following PRISMA guidelines, data were analyzed across gamma, electron, proton, neutron, and alpha irradiation, covering Sn-Pb, SAC305, AuSn20, SnBi, and related systems. Gamma irradiation predominantly accelerates interfacial diffusion kinetics, resulting in IMC thickening, oxidation, and shear strength reductions. However, the effects are dose-dependent, where low doses temporarily harden the material, while higher doses make it brittle. Lead-free SAC305 alloys exhibit greater radiation sensitivity than Sn-Pb systems, showing accelerated IMC growth, defect accumulation, and lattice instability. Proton and neutron irradiation induce displacement-dominated damage, including defect clustering and Kirkendall voiding. Combination of electron irradiation and thermal cycling produces synergistic degradation exceeding single-stressor effects. By integrating experimental findings with atomistic and multiscale modeling insights, this review links defect generation, interfacial instability, and mechanical degradation using established radiation-enhanced diffusion (RED) principles. The results clarify radiation-type-dependent damage mechanisms, highlight alloy-specific tolerance differences, and identify critical gaps in multi-stressor testing and predictive lifetime modeling. The mechanistic insights presented here serve as a foundation for optimizing solder alloy design and strengthening qualification procedures for radiation-prone electronic applications.