Abstract
Vacuum brazing of A5000 (Al-Mg) series and A6000 (Al-Mg-Si) series aluminum alloys are considerably difficult because of their rather high magnesium contents. For the purpose of sound and high strength brazing of these materials, a series of Al-Ge-Si-Mg system based filler metales was developed by the authors. Evaluations of brazed joint strength of A5052 and A6061 base alloys with these filler metals were performed and the relationship between the joint strength and the brazing conditions was investigated.
In A6061 base alloy, the brazed joints provided sufficient joint strength which were equal to that of the base alloy. In A5052 alloy, on the other hand, the joint strength was considerably low which was as low as one half of that of the base alloy.
The examination of brittle intermetallic compound Mg2Ge through the reaction between Mg in the base alloys and Ge in the filler metals occured at the interfaces of the brazed joints. Accordingly the formation of this intermetallic compound lead the decrease in the joint strength of A5052 alloy, which contains much Mg.
