SnCu钎焊接头稳态蠕变本构方程建立

以搭接面积为1 mm2微型单搭接钎焊接头为研究对象,采用新型高温蠕变测试装置,测定了Sncu钎焊接头应力指数n和蠕变激活能Q,构建了稳态蠕变本构方程,探讨了蠕变变形机制.结果表明,在低温高应力下,SnCu共晶钎料钎焊接头应力指数为8.73,激活能在59.1～63.2 kJ/mol,位错攀移运动主要受位错管道扩散机制控制;在高温低应力区,Sncu共晶钎料钎焊接头应力指数为6.45,激活能在88.4～97.5 kJ/mol,位错攀移运动主要由晶格自扩散机制控制.

Foundation of steady state creep constitutive equation of SnCu soldered joints

SnCu eutectic solder alloys have been regarded as one of the most promising Pb-free substitutes for the SnPb solders for its low cost and good mechanical properties.Creep property of solder alloys is one of the important factors to affect the reliability of soldered joints.A novel high temperature creep strain equipment was used to test stress exponent and creep activation energy of single shear lap creep specimens of SnCu eutectic soldered joints with a 1 mm² cross-sectional area.The final constitutive equation of the composite soldered joints was established and its creep mechanism was investigated.Results indicate under low temperature and high stress, the stress exponents of the soldered joints is 8.73, and the creep activation energies is varied in 59.1-63.2 kJ/mol.The dislocation climbing is dominated by dislocation pipe diffusion process.Under high temperature and low stress, the stress exponents of the soldered joints is 6.45 and the creep activation energies is varied from 88.4-97.5 kJ/mol.The dislocation climbing is dominated by the lattice self-diffusion process.