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.