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新型的无铅钎料不仅要具备含铅钎料的工艺性能,更重要的是要有更高的力学性能,特别是焊接接头的抗蠕变能力。将纳米级多面齐聚倍半硅氧烷(Polyhedral oligomeric silsesquioxanes,POSS)颗粒作为增强相添加到基体钎料中,能够有效地改善Sn-3.5Ag基复合钎料的性能。研究了不同种类POSS增强颗粒对Sn-3.5Ag钎料显微组织和力学性能的影响,确定出POSS增强颗粒复合钎料的最佳配比,并对最佳配比复合钎料在不同温度不同载荷条件下的蠕变寿命进行了研究。结果表明:POSS颗粒质量分数小于2%时,可以抑制基板界面处初晶金属间化合物的生长;复合钎料的抗剪切强度明显提高;低温时,最大蠕变寿命明显改善。
The new lead-free solder not only has to have lead-containing solder process performance, more importantly, to have a higher mechanical properties, especially the resistance to creep welding joints. The addition of nano-sized polyhedral oligomeric silsesquioxanes (POSS) particles as a reinforcing phase to the matrix solder can effectively improve the performance of the Sn-3.5Ag-based composite solder. The effects of different kinds of POSS particles on the microstructure and mechanical properties of Sn-3.5Ag solder were studied. The best proportion of POSS particle-reinforced solder was determined, and the optimum proportion of composite solder at different temperatures The creep life under load is studied. The results show that when the mass fraction of POSS particles is less than 2%, the growth of primary intermetallic compounds at substrate interface can be restrained; the shear strength of composite brazing filler metal increases obviously; and the maximum creep life at low temperature is obviously improved.