Investigation of the joinabilitiy of AA5052/2024 alloys by friction stir welding method

Aluminium and its alloys have found wide application areas such as aircraft, aerospace and defence industries because of their inherent properties like a strength ? to ? weight ratio and high corrosion resistance and strength. It is difficult to join these alloys by conventional fusion welding processes. The slag waste, tunnel, porosities and macro inner stresses are the common problems and these defects decrease the strength of welded couples. Thus, it is now preferential to use of Friction Stir Welding (FSW) process, a new and alternative solid state welding method, to join dissimilar different alloys. Many welding defects including stresses can be minimised due to the no melting is occurred.In this study, different commercial AA2024 and AA5052 aluminum alloys have been welded by FSW process. The rotational speed of stirrer and feed rate parameters were changed in a certain interval according to the literature to explore their effects on mechanical and microstructural properties of welded couples. A triangular pyramid stirrer was used in all experiments. The welding zones were investigated under optical microscopy. The tensile and fatigue tests were employed to study to determine the mechanical properties of welded alloys. The fracture surface of fatigue specimens were examined under Scanning Electron Microscope (SEM). As a result, it is concluded that the mechanical properties of welded couples could be improved by selecting suitable welding parameters.This study consists of eight chapters. In the first chapter, the subject was introduced. In the second chapter the place of study in the literature was investigated and the aim was pointed out. In the third chapter, the aluminum and its alloys and in the fourth chapter the FSW process was presented. In the fifth chapter, the fatigue behaviors of metals were presented. In the sixth chapter, the method of experimental study and the preparation phases were presented. In the seventh chapter, the experimental results were given and discussed in details. In the eight and final chapter, the general results and recommendations were given.Keywords: Friction stir welding, microstructure, fatigue test, mechanical properties.