Microstructure and mechanical properties of 5083 aluminum alloy/E36 steel fusion-brazed joint

Fusion-brazed joint between 4 mm thick 5083 aluminum alloy and E36 steel was obtained by GTAW with Zn-Al22 flux-cored filler wire. The influence of welding current on formation of joint,intermetallic compounds and tensile strength of the joint was investigated.η-Fe₂Al₅Zn_x intermetallic compound layer with small amount of scattered δ-FeZn₁₀ formed at the steel/weld interface. While increasing the welding current,the weld width grew larger,the spreading and wetting of molten metals on the surface of E36 steel was promoted,and the thickness of η-Fe₂Al₅Zn_x intermetallic compound layer and the amount of δ-FeZn₁₀ also increased. When the welding current was above 120A,Fe-Zn intermetallic compound layer formed in the interface. The thin η-Fe₂Al₅Zn_x intermetallic compound layer and the scattered δ-FeZn₁₀ within η-Fe₂Al₅Zn_x is beneficial for improving the tensile strength of the joint. All aluminum alloy/steel fusion-brazed joints fractured through the steel/weld interface,and the tensile strength of the joint reached the peak value of 120 MPa when the welding current was 110 A.