Effect of wire deposition rate on macro and microscopic characteristics of laser weld-brazed AA5083 aluminum alloy to galvanized steel joints and their corrosion response

In this study, dissimilar metals, such as aluminium (AA5083) and galvanised interstitial free steel, were laser-brazed in a flange configuration using eutectic filler aluminium wire (4047, Al-12%Si). To investigate the effects of wire deposition rate on the characteristics of laser-brazed joints and to understand the factors contributing to corrosion in these joints. The wire deposition rates were varied while keeping other laser parameters constant. Changes in wire deposition rate were observed to affect the flow behaviour of molten metal leading to variations in the geometrical characteristics of the brazed joints and interfacial reactions as revealed by macroscopic examination. A series of corrosion tests, including electrochemical, immersion, and salt spray tests, were conducted on the laser-brazed joints. It was demonstrated by Immersion corrosion tests that the wire rate influenced the corrosion results for the laser-brazed joints. However, the salt spray test showed no substantial effect on corrosion with respect to different wire deposition rates. Furthermore, the electrochemical results indicated significant changes in the corrosion response of the brazed zone due to the presence of chemically dissimilar phases. A correlative discussion between laser parameters, observed microstructure, and their effects on the corrosion performance of the brazed samples is presented.