The influence of silicon content on the microstructure and corrosion behavior of Laser welding-brazed steel/aluminum joint

Laser welding-brazing is an ideal method for connecting galvanized steel and aluminum alloys. In this paper, the influence of silicon content on the microstructure and corrosion behavior of laser welding-brazed steel/aluminum joint was studied. The results indicate that silicon content can improve the wettability and control the growth of inter-metallic compound (IMC) layer. The average thickness of IMC layer is all less than 5μm. Fe-Al-Si solid solution can be found in IMC layer. Fe 2 Al 5 Si 0.2 and FeAl 3 Si 0.09 were found in seam with AlSi 5 filler metal. Fe 2 Al 5 Si 0.45 and FeAl 3 Si 0.17 are found in seam with AlSi 12 filler metal. The results of tensile test show that with the increase of silicon content, the joint can achieve good mechanical property. Corrosion test results indicate that Zn-rich zone and IMC layer are most susceptible to corrosion in NaCl or CH 3 COOH solution.