B. Tweedy, B. Kumar, National Institute of Aviation Research, Wichita State University, Wichita, KS; C. D. Allen, South Dakota School of Mines & Technology, Rapid City, SD

Summary:

The friction stir joining process has seen increasing application in the aerospace industry. In order to continue the development of these applications, it is important to characterize the mechanical and corrosion properties of friction stir welded joints in alloys, thicknesses and configurations representative of the aerospace industry. The objective of this work was to investigate the joining feasibility and mechanical characteristics of friction stir welding thin sheet (0.040�) 2024-T3 to 2024-T3 and 7075-T73 to 7075-T73 aluminum alloys in a butt joint configuration. Mechanical properties from tensile, fatigue and fatigue crack propagation were determined along with exfoliation corrosion resistance of the welded sheets. All samples were naturally aged for a period of at least 3 months prior to testing with no additional post-weld heat treatment. Yield strength, ultimate tensile strength, and percent elongation are found for each alloy. A laser extensometer and bi-axial extensometer was used to gather data to calculate the ultimate strain. Exfoliation testing shows greater depth of penetration in the 2024 aluminum than the 7075 alloy. Process technique, processing parameters, and tooling are presented.