金属镀层对铝/钢激光熔钎焊接头组织与性能的影响

针对在铝/钢焊接过程中,钢的表面金属镀层对铝/钢激光熔钎焊接头性能有着重要影响的问题,研究铝合金在不同金属镀层的低碳钢表面的铺展效果,通过SEM对不同金属镀层下熔钎焊接头界面微观组织形态、金属间化合物厚度、种类等进行分析,并进一步研究不同金属镀层下铝/钢接头的力学性能及断口形貌。结果表明:钢表面的金属镀层对铝/钢激光熔钎焊过程中5A06铝合金在钢上的铺展与浸润有着较大的影响,其中5A06铝合金在镀铝钢上的铺展效果最佳,且铝合金与镀铝锌钢熔钎焊的接头抗拉性能最好,达到母材铝合金的70%。铝/钢界面金属间化合物主要由铝铁金属间化合物组成,其中在镀铝钢、镀铝锌钢、镀锌钢中主要存在Fe2Al5,FeAl3,FeAl等金属间化合物,在镀镍钢界面中还存在Fe4Al13等金属间化合物。

Effect of Metal Coating on Microstructure and Properties of Aluminum/Steel Laser Welding-Brazing Joint

For aluminum/steel laser brazing-welding,metal coating on the surface of steel has an im-portant impact on the performance of aluminum/steel joint.Spreading effect of the liquid of 5A06 alu-minum alloy on low carbon steel surface with the various metallic coatings was studied.Microstruc-ture of the interface,thickness and kinds of intermetallic compound of the welding-brazing joint were analyzed by SEM,and the mechanical properties and fracture appearance of aluminum/steel joint with different metallic coatings on steel were further investigated.The results show that the spreading effect and infiltration are impaired by metal coating on the steel surface in the aluminum/steel laser welding-brazing.The spreading effect of aluminum lap with aluminized steel is the best,and the ten-sile property of the lap joint of aluminum alloy and aluminized zinc steel is the best,which accounted to base metal aluminum alloy for 70%.The Fe2Al5,FeAl3and FeAl intermetallic compounds are dis-covered at the weld interface of aluminum/steel laser brazing-welding by using aluminum-coated steel, aluminized steel or galvanized steel,and the Fe4Al13intermetallic compounds is existed in the interface of aluminum/steel with nickel plated steel.