Double-Side Friction Stir Welded Cast 2297 Al-Cu-Li Alloy at Various Parameters

In this study, a novel cast 2297 Al-Cu-Li alloy was welded through double-side friction stir welding using different process parameters. The formation quality, mechanical properties and microstructures of joints were evaluated. Results showed that the well-formed joints were obtained under appropriate welding parameters with relatively good performance, indicating that this joint form can be applied to structural design. The optimum parameters in this welding condition were obtained. The weakest region of the mechanical properties of joint was found in the heat-affected zone on the retreating side of the first weld side. During the welding process, most strengthening phases were dissolved, whereas the delta'/beta' and Omega phases were formed again in the stir zone. The re-dissolution of the strengthening phases and grain coarsening in the welding process were the main reasons accounted for the decrease in the mechanical properties of the joints.