Friction Stir Weld Lap Joint Properties in Aeronautic Aluminium Alloys

Abstract

A study of properties of Friction Stir Weld lap joints performed with the AA7075-T6 aluminum alloy used in aerostructure manufacturing are presented in this work. The effects of different tool designs and welding parameters in the weld cross sectional and mechanical properties of the joints were investigated. The weld cross sectional features were analyzed by metallographic examination while the mechanical properties were studied by microhardness measurements. Typical features of Friction Stir Weld lap joints have been identified such as hook features, cold lap defects or joint line uplifting. The extension of Heat Affected Zone regions and mechanical property reduction was evaluated depending on the welding parameters used to perform the Friction Stir Weld joints. The tool design as well as welding conditions that minimize defects such as effective sheet thinning, hardness drops or wide Heat Affected Zone regions were established.