Effect of gamma-ray irradiation on microstructure and mechanical property of Sn63Pb37 solder joints
In order to meet the reliability requirement of solder joints for future small satellite, the effect of γ-ray irradiation on the microstructure and mechanical property of Sn63Pb37 solder joints was investigated by scanning electron microscope observation and mechanical testing. The results showed that γ-ray irradiation possessed few influence on the thickness and morphology of intermetallic compound layer of Sn63Pb37/Cu. But the mechanical properties of solder joints were reduced with micro-voids and micro-cracks appearing in Pb-based solid solution during irradiation process. Energetic electrons created by γ-ray through Compton Effect, generated dislocated atoms which eventually resulted in the formation of microscopic defects and the decrement of mechanical property. After 960 h γ-ray irradiation at the dose rate of 0.25 Gy(Si)/s, the shear force of Sn63Pb37 solder joints was decreased by 11.47%. Compared with as-soldered joint, the ductility of irradiated solder joints was reduced with more unobvious shear dimples and lower impact toughness.
This project was supported by National Natural Science Foundation of China (Grant No. 51675269) and the Priority Academic Program Development of Jiangsu Higher Education Institutions (PAPD).