Ga和Ce复合添加对低银无镉钎料组织及性能的影响

Effects of Ga and Ce on the Microstructure and Properties of Cadmium-free Silver Filler Metals

摘要:

通过向Ag17CuZnSn钎料中复合添加微量的Ga元素和稀土元素Ce,研究了Ga和Ce元素的复合添加对低银无镉钎料组织及焊接性能的影响。采用火焰钎焊方法得到黄铜与不锈钢异种金属钎焊接头。试验表明,随着Ga和Ce元素的添加低银钎料的固液相线温度不断下降。当Ga和Ce含量分别为2%和0.15%时,钎料在母材表面的铺展面达到最大值。Ga和Ce元素的复合添加对低银钎料中的CuZn化合物相有明显的细化作用,黄铜与不锈钢钎焊接头的抗剪强度最大值为378.6 MPa。在钎焊过程中,钎缝与不锈钢母材之间发生了明显的元素扩散,Ga元素的扩散率大于其他元素。同时当低银钎料中的Ce元素含量大于0.3%时,钎料组织中出现了新生成的块状的稀土相。

Abstract:

Effects of Ga and Ce additions on the microstructures and mechanical properties of Ag17CuZnSn-xGa-yCe filler metals and brazed joint were investigated by microscopy method and tensile test. The results indicated that the solidus and liquidus temperatures of filler metals decreased with addition of Ga and Ce. And the wettability of filler metals on the brass and stainless steel improved when the content of Ga and Ce are 2 wt. % and 0.15 wt.%. The highest shear strength of brazed joint was 3% higher than the shear strength of the Ag17CuZnSn-2Ga. During brazing process, Ga has a higher diffusion coefficient into stainless steel than that of other elements. A novel Ce₂₀(Ag, Cu)₄₀Sn₄₀ intermetallic phase was found in filler metal when the content of Ce is higher than 0.3 wt.%.