Transitional layers brazing of Al-alloy and stainless steel

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 0Cr18Ni9.