Effects of zinc on the laser welding of an aluminum alloy and galvanized steel

The fusion-brazing connection of 5052 aluminum alloy and ST07Z galvanized steel was achieved using a Nd:YAG laser, and the effects of the zinc layer on the forming properties of the fusion-brazing bead and the growth behaviors of the intermetallic compound (IMC) were investigated. The results indicate that the galvanized layer can particularly change the initial conditions of the brazing, reducing the brazing temperature from near the melting point of Fe (1535.0 degrees C) to that of Al (660.4 degrees C). The IMCs can transform from the Fe2Al5 and FeAl3 phases, which were observed in the interface of the aluminum/non-galvanized steel pair to the Fe2Al5Zn0.4 phase, which was observed in the interface of the aluminum/galvanized steel pair; this phenomenon occurs when zinc atoms are substituted for iron atoms during the formation of the IMCs. (C) 2015 Elsevier B.V. All rights reserved.