Effects of γ-ray irradiation on microstructure and mechanical property of AuSn20 solder joint

Abstract

In this study, MoCu20/Cu joints via eutectic bonding recipe with AuSn20 solder were obtained to investigate the effect of γ-ray irradiation on the microstructure and mechanical properties of the solder joints. Firstly, the experimental results showed that the number and size of voids in joints were gradually increased during irradiating process due to the migration and agglomeration of irradiation-induced vacancies. Secondly, the (Au,Ni)Sn and (Ni,Au)3Sn2 IMC layers and Au-rich joints were formed by the activation of interfacial reaction between Au–Sn solder and plating metal. Thirdly, the failure mode was altered from ductile fracture to brittle fracture, and the shear strength of joint was decreased by 37.23% after 1000 h γ-ray irradiation in the results of mechanical test. In summary, the γ-ray irradiation has a highly detrimental influence on the AuSn20 solder joint.