Analysis for Al-Fe intermetallic compounds layer of fusionbrazed joints between aluminiumand zinc-coated steel by hybrid welding

The structure of Al-Fe intermetallic compounds in fusion-brazed joints between aluminium and zinc-coated steel was analyzed.Influence of welding energy input on the thickness of the Al-Fe intermetallic compounds layer was studied.And the influence of the thickness of the Al-Fe intermetallic compounds layer on the shear strength of joints was also studied.The results indicated that the intermetallic compounds layer was composed of Fe₃Al, FeAl₂, Fe₂Al₅ and FeAl₃, and these binary intermetallic compounds exhibited an enrichment of silicon near the weld metal side.The intermetallic compounds layer became more and more thicker along with the increasing of the welding energy input.But the effect of arc energy on the thickness of the layer was more remarkable than that of laser energy.A thinner or thicker Al-Fe intermetallic compounds layer could reduce the strength of the joints.When the the thickness of Al-Fe intermetallic compounds layer was within 1.5-4 μm, the influence of the layer on mechanical property of the joint was not significant.