Microstructure and Shear Properties Evolution of Minor Fe-Doped SAC/Cu Substrate Solder Joint under Isothermal Aging  

作　　者：Quanzhen Li Chengming Li Xiaojing Wang Shanshan Cai Jubo Peng Shujin Chen Jiajun Wang Xiaohong Yuan 

机构地区：[1]Jiangsu University of Science and Technology,Zhenjiang,212003,China [2]R&D Center,Yunnan Tin Group(Holding)Co.Ltd,Kunming,650000,China [3]The 58,Research Institute of China Electronics Technology Group Corporation,Wuxi,214100,China [4]Yunnan Precious Metals Lab,Sino-Platinum Metals Co.,Ltd,Kunming,650156,China

出　　处：《Acta Metallurgica Sinica(English Letters)》2024年第7期1279-1290,共12页金属学报（英文版）

基　　金：supported by the Yunnan Fundamental Research Projects(No.202301BC070001-001)funded by the Yunnan Provincial Department of Science and Technology;the Yunnan Provincial Science and Technology Plan Project(No.202005AF150045);the Jiangsu Province Industry-University-Research Cooperation Project(No.BY2022832)funded by the Jiangsu Provincial Department of Science and Technology;the National Natural Science Foundation of China(No.52275339).

摘　　要：Different amounts of Fe(0.005,0.01,0.03,0.05,and 0.07 wt%)were added to SAC305 to study the shear behavior damage of Fe-doped SAC solder joints under thermal loading(170℃,holding time of 0,250,500,and 750 h).The results show that during isothermal aging at 170℃,the average shear force of all solder joints decreases with increasing aging time,while the average fracture energy first increases and then decreases,reaching a maximum at 500 h.Minor Fe doping could both increase shear forces and related fracture energy,with the optimum Fe doping amount being 0.03 wt%within the entire aging range.This is because the doping Fe reduces the undercooling of the SAC305 alloy,resulting in the microstructure refining of solder joints.This in turn causes the microstructure changing from network structure(SAC305 joint:eutectic network+β-Sn)to a single matrix structure(0.03Fe-doped SAC305 joint:β-Sn matrix+small compound particles).Specifically,Fe atoms can replace some Cu in Cu_(6)Sn_(5)(both inside the solder joint and at the interface),and then form(Cu,Fe)_(6)Sn_(5) compounds,resulting in an increase in the elastic modulus and nanohardness of the compounds.Moreover,the growth of Cu_(6)Sn_(5) and Cu_(3)Sn intermetallic compounds(IMC)layer are inhibited by Fe doping even after the aging time prolonging,and Fe aggregates near the interface compound to form FeSn_(2).This study is of great significance for controlling the growth of interfacial compounds,stabilizing the microstructures,and providing strengthening strategy for solder joint alloy design.

关 键 词：SAC305 solder Fe doping Shear mechanical behavior Isothermal aging Interfacial intermetallic compounds(IMC) 

分 类 号：TG407[金属学及工艺—焊接]