中国有色金属学报(英文版)
Transactions of Nonferrous Metals Society of China
| Vol. 36 No. 3 March 2026 |
（a National Key Laboratory of Precision Welding & Joining of Materials and Structures, Harbin Institute of Technology, Harbin 150006, China;
b Zhengzhou Research Institute, Harbin Institute of Technology, Zhengzhou 450046, China;
c Beijing Institute of Control Engineering, Beijing 100094, China;
d Heilongjiang Institute of Atomic Energy, Harbin 150086, China）
Abstract:The effects of γ-ray and electron irradiation on the microstructural evolution and mechanical properties of SnPb eutectic solder joints were investigated. Following electron irradiation, the SnO2 phase induced by γ-ray irradiation transformed into β-Sn, and the dislocation density in the β-Sn crystal decreased. Moreover, numerous point defect clusters formed in the β-Sn crystal, some of which transformed into an amorphous phase, increasing the amorphous layer thickness. Meanwhile, electron irradiation likewise resulted in rotation of the (220) plane of β-Sn nanograins and reduction of SnO2 in the β-Sn crystal. Additionally, upon exposure to γ-ray and electron irradiation, the average shear strength of the solder balls was initially increased by 10.10%, followed by a decrease of 3.53% and 4.77%, respectively. The plasticity and the dimple count on the fracture surfaces of the solder joint initially decreased but subsequently increased.
Key words: combined irradiation; SnPb eutectic solder joints; SnO2 reduction; irradiation damage; β-Sn nanograin rotation
