Extensive testing was carried out to study the effects of rare earth Ce doping on the properties of SnAgCu solder alloys.The addition of 0.03%(mass fraction) rare earth Ce into SnAgCu solder may improve its mechanical...Extensive testing was carried out to study the effects of rare earth Ce doping on the properties of SnAgCu solder alloys.The addition of 0.03%(mass fraction) rare earth Ce into SnAgCu solder may improve its mechanical properties,but slightly lower its melting temperature.The tensile creep behavior of bulk SnAgCuCe solders was reported and compared with SnAgCu solders.It is found that SnAgCuCe solders show higher creep resistance than SnAgCu alloys.Moreover,Dorn model and Garofalo model are successfully used to describe the creep behavior of SnAgCu and SnAgCuCe alloys.The parameters of the two creep constitutive equations for SnAgCu and SnAgCuCe solders are determined from separated constitutive relations and experimental results.Nonlinear least-squares fitting is selected to determine the model constants.The experimental data of the stress-creep strain rate curves are in good agreement with the theoretical ones.展开更多
Intermetallic compounds(IMC) formed at Sn-Ag-Cu solder droplet/pad interface during wetting reaction were investigated. Comparative studies of the IMC evolution during reflow and aging were also conducted. The results...Intermetallic compounds(IMC) formed at Sn-Ag-Cu solder droplet/pad interface during wetting reaction were investigated. Comparative studies of the IMC evolution during reflow and aging were also conducted. The results show that the wetting reaction between molten solder droplet and pad leads to the formation of Au-Sn compound at interface, but Au element is not fully consumed during wetting reaction. After reflow, all Au layer disappears from the interface, Au element is dissolved into solder and Au-Sn intermetallic compounds are precipitated in the bulk. Reaction between Ni layer and Sn-Ag-Cu solder leads to the formation of (CuxNi1-x)6Sn5 layer at interface during reflow. According to the thermodynamic-kinetic of interfacial reaction, the wetting reaction at solder droplet/pad interface influences the phase selectivity of IMC evolution during reflow and aging process.展开更多
基金Project(BCXJ09-07) supported by Doctoral Dissertation Innovation and Excellence Producing Foundation of Nanjing University of Aeronautics and Astronautics,ChinaProject(CX07B_087z) supported by the Jiangsu General Colleges and Universities Postgraduate Scientific Research Innovative Plan,China
文摘Extensive testing was carried out to study the effects of rare earth Ce doping on the properties of SnAgCu solder alloys.The addition of 0.03%(mass fraction) rare earth Ce into SnAgCu solder may improve its mechanical properties,but slightly lower its melting temperature.The tensile creep behavior of bulk SnAgCuCe solders was reported and compared with SnAgCu solders.It is found that SnAgCuCe solders show higher creep resistance than SnAgCu alloys.Moreover,Dorn model and Garofalo model are successfully used to describe the creep behavior of SnAgCu and SnAgCuCe alloys.The parameters of the two creep constitutive equations for SnAgCu and SnAgCuCe solders are determined from separated constitutive relations and experimental results.Nonlinear least-squares fitting is selected to determine the model constants.The experimental data of the stress-creep strain rate curves are in good agreement with the theoretical ones.
文摘Intermetallic compounds(IMC) formed at Sn-Ag-Cu solder droplet/pad interface during wetting reaction were investigated. Comparative studies of the IMC evolution during reflow and aging were also conducted. The results show that the wetting reaction between molten solder droplet and pad leads to the formation of Au-Sn compound at interface, but Au element is not fully consumed during wetting reaction. After reflow, all Au layer disappears from the interface, Au element is dissolved into solder and Au-Sn intermetallic compounds are precipitated in the bulk. Reaction between Ni layer and Sn-Ag-Cu solder leads to the formation of (CuxNi1-x)6Sn5 layer at interface during reflow. According to the thermodynamic-kinetic of interfacial reaction, the wetting reaction at solder droplet/pad interface influences the phase selectivity of IMC evolution during reflow and aging process.
