AZ31B/7075-T6 alloys friction stir lap welding with a zinc interlayer

Pure zinc foil was selected as an interlayer to improve the strength of the AZ31B Mg/7075-T6 Al dissimilar alloys friction stir lap welding joint. Compared with the conventional lap joint, the joint with the zinc interlayer has a higher effective sheet thickness, a larger effective lap width and a wider stir zone. The dispersed Mg-Zn inter metallic compounds are achieved instead of the continuous Mg-Al intermetallic compounds, improving the tensile shear load. The maximum fracture load of the joint with the zinc interlayer reaches 6.6 K N at the rotating velocity of 1000 rpm.