Al-Si-Ge-Zn钎料钎焊6061铝合金接头组织与性能分析

Microstructure and property of 6061 aluminum alloy brazed joint with Al-Si-Ge-Zn filler metal

采用新型Al-Si-Ge-Zn钎料钎焊6061铝合金,对钎料及钎焊接头的组织和性能进行了分析,并与Al-Si-Zn和Al-Si-Ge钎料进行了对比.结果表明,Al-Si-Ge钎料熔点较低,但高的Ge元素含量促使钎缝中形成粗大的脆性初生Ge Si相,恶化了钎焊接头组织和性能;Al-Si-Zn钎料由于Zn元素含量较高,引起钎缝中Si元素偏析聚集为大片状,严重影响钎焊接头的力学性能;向Al-Si共晶中添加适量的Ge和Zn元素,维持了较低的钎料熔化温度,同时细化了钎料合金的显微组织,脆性初生Ge Si相和片状硅相消失,细小分散的锗,硅固溶体相均匀分布在α-Al基体中.采用Al-Si-Ge-Zn钎料钎焊6061铝合金,钎焊接头抗剪强度最大.

Brazing of 6061 aluminum alloy is carried out using novel Al-Si-Ge-Zn filler metal,and the microstructure and properties of filler metal and brazed joint are analyzed. Additionally,the traditional Al-Si-Zn and Al-Si-Ge filler metals are also used for comparison. The results show that Al-Si-Ge filler metal has lower melting point,but the high Ge content generates coarse Ge Si phases in the brazed seam,and the microstructure and property of brazed joint are deteriorated by these coarse phases.High Zn content in Al-Si-Zn filler metal causes aggregation of Si into big lamellar structure,which affects the property of brazed joint. Adding appropriate Ge and Zn into Al-Si eutectic can not only keep low melting temperature,but also refine the microstructure of the filler metal. Uniform and fine Ge and Si solid solution phases distribute in the α-Al substrate without coarse Ge Si and lamellar Si phases. The brazed 6061 aluminum alloy joint has the maximum shear strength with Al-Si-Ge-Zn filler metal.