Study on the dissimilar magnesium alloy and copper lap joint by TIG welding

Dissimilar magnesium alloy and copper were welded by TIG in the form of lap welding. Intermetallic compounds in the interfacial region of the dissimilar joint were observed. It was shown that the intermetallic compounds were the cause of the joint embrittlement. The tensile strength of the joint was about 25 MPa. While with the iron plate as interlayer, the embrittleness of joint was obviously decreased, the tensile strength of the joint was about 70 MPa and the failure took place between iron plate and magnesium alloy. Metallic oxides were found in the interfacial region between iron plate and magnesium alloy. The occurrence of metallic oxides was the main reason influenced the strength of weld.