Effects of powder on microstructure, tensile, and corrosion behavior of aluminum-steel joints

Using laser welding-brazing technique to join 5A06 Al alloy and ST04Z galvanized steel, the authors study the effect of adding pure powder (Si, Mg, Mn, or Zn) in the joining on the material behavior of welded joints. The results show that the microstructures, tensile behavior, and corrosion behavior of the welded joints are dependent on the powder used in the welding. An intermetallic compound (IMC) layer consisting of Fe₂Al₅ and FeAl₃ is formed between the Al alloy and the steel, which is independent of the pure element powder used. The IMC layer with the use of Zn powder has the least thickness. The welded joints with the use of pure Mg element powder have the largest corrosion resistance.