Microstructural characterization of friction stir welded AA5083 aluminum alloy joints

Abstract

The objective of the current work is to apply Taguchi L9 orthogonal array to enhance the welding process factors for friction stir welding (FSW) of AA5083 aluminium alloy plates. Using a randomized procedure, the Taguchi orthogonal array was implemented to identify the FSW process parameters such as the rotating speed of the tool, welding speed, and tilting angle of the tool. The optimum welding parameters for the ultimate tensile strength and hardness of the joints were predicted and the individual rank of each process parameter on the ultimate tensile strength and hardness of the friction stir weld was assessed by investigative ANOVA results and the S/N ratio (signal-to-noise ratio). The most desirable rotational speed of the tool, welding speed and tilting angle of the tool were 600 rev. per. min, 70 millimeter/min and 1o appropriately for the ultimate eluting strength and 600 rev. per. min, 80 millimeter/min and 1o correspondingly for summit joint hardness. The outcomes of Analysis of Variance (ANOVA) designated that the tilting angle of the tool has the higher statistical effect succeeded by the welding velocity and rotational speed of the tool. Furthermore, metallurgical properties of the weld cross-sections were investigated by using optical microscope (OM), scanning electron microscope (SEM), energy dispersive spectroscopy (EDS) analysis. The microstructure of the stir zone reveals finer grain structure, directed to the higher hardness, which gives rise to higher tensile strength.