铝合金与不锈钢的过渡层钎焊

Transitional layers brazing of Al-alloy and stainless steel

铝合金与不锈钢的物化性能相差很大 ,两者的直接连接易于在界面上生成Al和Fe的脆性化合物。作者用试验的方法研究了LF3铝合金与 0Cr18Ni9不锈钢的Ni/Cu过渡层钎焊的工艺方法以及接头的组织与力学性能 ,并对各连接界面进行了机理分析。对钎缝的界面做剪切试验、X射线衍射、扫描电镜 (SEM )和透射电镜 (TEM )等分析发现 ,镀层与钎料等各界面连接紧密 ,特别是钎缝与母材之间没有生成脆性Al-Fe金属间化合物。由此得出结论 ,面心立方结构的Ni/Cu电刷镀层能有效地阻挡Al、Fe等原子扩散 ,钎缝与镀Cu界面上虽然生成了少量的AlCu3 ,但由于组织不连续 ,没有大幅度降低钎缝的剪切强度。通过过渡层钎焊 ,实现了LF3铝合金与 0Cr18Ni9不锈钢的复合连接 ,满足了工程需要。

Stainless steel has so much difference from Al and Al alloy with the character of physics and chemistry. It is prone to produce brittle compounds on the binding interfaces in the direct brazing of Al alloy and stainless steel. This paper has investigated the joining performance, interface microstructures and mechanical properties of Al alloy-stainless steel indirect brazing with brushing Ni/Cu layers on stainless steel by tension test, X-ray diffraction, EDAX , SEM and TEM. The most important is that there is no brittle compound on the joint. It is concluded that Ni and Cu layers has effectively hindered the atoms of Al and Fe diffusing from each other. Though there is some AlCu3 produced, its quantity is too little to affect the strength of the joints. This process has succeeded in composite joint of LF3 with 0Crl8Ni9.