Characterization of 2024-T351 friction stir welding joints

Abstract

Characterization of macrostructure, microstructure, hardness, precipitate distribution, residual stress, and cyclic deformation behavior of 2024-T351 friction stir welded joints has been conducted. Inhomogeneous microparameters governing the nonuniform residual stresses and cyclic strength are discussed. The cyclic strength of the weld microregimes is controlled by grain size and distribution of precipitates achieved during the weld process. The comprehensive information of micro-and macromechanics is used to assist in understanding the mechanism that governed the fatigue crack initiation, propagation, and life of the welded joints.

Influence of tool geometry and rotational speed on mechanical properties and defect formation in friction stir lap welded 5456 aluminum alloy sheets

“…Welding is carried out around 70-90% of the base material melting point so it is important that the tool material possess sufficient strength at these temperatures to avoid intense wear or fracture during the FSW process [5]. 3 Because of the important role played by tool geometry in process optimization of FSW, a large number of studies have been reported in the literature on the effect of tool geometry on microstructure evolution and mechanical properties [6][7][8][9][10][11][12][13][14]. Of particular interest, is the work of Fuji et al [7] on the effect of tool shape on mechanical and microstructural properties of friction stir welded 1050-H24, 6061-T6, and 5083-O aluminum plates.…”

Application of Numerical Method to Investigation of Fatigue Crack Behavior Through Friction Stir Welding

“…Friction stir welding (FSW) is a type of solid state welding, invented in 1991 by The Welding Institute (TWI) in Cambridge, U.K., which involves a joining process using no filler materials [1][2][3]. The FSW process is somewhat different from other types of welding in that a threaded or nonthreaded pin, installed on a cylindrical tool, approaches the joint line of two butted plates while rotating quickly with a constant spinning speed and is inserted into the plates.…”

“…The pin starts to translate along the joint line while still rotating, as shown in Fig. 1 [1][2][3][4][5]. During the welding process, the cylindrical tool is forced down toward the plates to make effective contact between the pin, shoulder, and plate surfaces.…”

“…Pin rotation deforms both plate materials plastically and drags some amount of material from the front to the backside, effectively stirring them. This operation joins the sheets together [1,5].…”

“…One of the significant problems with FSW joints that has attracted intensive study is fatigue crack behavior and propagation through the welded joints [1,5,[7][8][9][10]. Ingraffea et al [11] was one of the first who simulated the mixed-mode crack growth, applying the boundary element method (BEM).…”