Effect of joining parameters on microstructure of dissimilar metal joints between aluminum and galvanized steel

•Weld joints obtained with different welding parameters were investigated.•The phases of the intermetallic compound layer at the interface were studied.•Effect of heat input in base metal on the intermetallic phases was discussed.•Thermodynamic calculation was carried out for the Fe2Al5 and FeAl3 phases.•The formation process of the intermetallic compound layer was analyzed.