Ga2O3对Ag30CuZnSn药芯银钎料钎缝组织及钎焊接头性能的影响

Effect of Ga2O3 on of microstructure and properties of brazed joints obtained by Ag30CuZnSn flux cored brazing filler metal and brass

向Ag30CuZnSn药芯银钎料药粉中添加Ga2O3,研究了Ga2O3对Ag30CuZnSn药芯银钎料钎缝组织的影响及钎焊接头性能的影响.结果表明,微量Ga2O3可以显著提高Ag30CuZnSn药芯银钎料的润湿铺展性能且可以减少药芯中钎剂的添加量.Ga2O3添加量为0.4%(质量分数)时,钎料润湿铺展性能和钎焊接头抗剪切强度达到最佳值.这是因为Ga2O3属于表面活性物质,可以显著降低熔融钎料和母材之间的界面张力,从而提高了钎剂粉末的去膜效果,进而提高银钎料的润湿铺展性能.药芯银钎料基体及钎缝组织主要由以CuZn相为主的固溶体、银基固溶体和铜基固溶体构成.火焰钎焊时,添加0.4%Ga2O3(质量分数)时作用效果最佳,钎缝组织的细化与钎着率的提高(钎着率提高至95%以上)使得钎焊接头抗剪强度提高了11%以上,钎焊接头断口组织的形貌证明了上述结果.

The effect of Ga2O3 on the microstructure and properties of brazed joints formed by Ag30CuZnSn flux cored brazing filler metal brazed brass was studied when adding Ga2O3 into flux cored brazing powders.The results showed that the micro amount of Ga2O3 additions can significantly improve the wettability of Ag30CuZnSn flux cored brazing filler metal and reduce the flux additions.When the content of Ga2O3 was 0.4%,the wettability of Ag30CuZnSn flux cored brazing filler metal and the shear strength of brazed joint was up to the optimum.This was attributed to the fact that Ga2O3 was a surfactant,which can significantly reduce the interfacial tension between the molten brazing filler metal and the base metal,to improve the effect of removing oxide film of flux powders.Finally,the wettability of Ag30CuZnSn flux cored brazing filler metal was improved.In the process of flame brazing,when Ga2O3 addition was 0.4%,the shear strength of brazed joint was increased by more than 11%owing to the microstructure refinement of brazing seam and the increase of brazed rate(the brazed rate was increased to more than 95%).The fracture morphology of the brazed joint proved the above results.