铟对低银Ag-Cu-Zn钎料显微组织和性能的影响

研究了低银Ag-Cu-Zn钎料(ωAg≤20%)的熔化特性、铺展性能、钎料显微组织。以黄铜/304不锈钢作为母材,采用火焰钎焊方法,进行了搭接钎焊试验。结果表明,低银Ag-Cu-Zn钎料显微组织主要由铜基固溶体、银基固溶体、Cu Zn化合物相构成。In的添加降低了Ag-Cu-Zn钎料的固、液相线温度,改善了钎料润湿性能;添加In的低银Ag-Cu-Zn钎料在凝固过程中析出富In的银基固溶体,起到了固溶强化的效果,改善了钎焊接头的显微组织,从而提高了钎缝接头的力学性能。使用17Ag Cu Zn-1In火焰钎焊黄铜/304不锈钢,钎焊接头成形美观、组织致密、无缺陷存在,综合性能与含银量为25%的BAg25Cu Zn Sn银钎料的性能相当,节银效果显著。

Influences of In on the Microstructure and Mechanical Properties of Low Silver Ag-Cu-Zn Filler Metal

To develop novel low silver based filler metals used for brazing brass and 304 stainless steel. The microstructure morphology and the wettability of low silver based filler metals were observed by using scanning electron microscopy (SEM) and electrical resistance furnace. The results indicate that, the wettability of the low silver based filler metals imporved with increasing indium content. Brass and stainless steel were brazed with flame method, the mechanical properties of lap joint were tested and analyzed at the same time. It is found that the tensile strength of joints increased with the addition of indium due to the solution strength effect. The shear strength of joint brazed with the 17AgCuZn-1In filler metal reached 312.6MPa closes to joint brazed with the B25AgCuZnSn filler metal. The joints part formed via brazing the 304 stainless steel and brass with 17AgCuZn-1In by flame brazing, had no defects at all, which, meanwhile, proved its good performance.