Abstract
The Friction Stir Welding (FSW) process was invented and developed at The Welding Institute of United Kingdom in the year 1991 for solid state joining of aluminum and its alloys. Subsequently, this welding process has been used for joining other materials like magnesium, titanium and copper alloys, stainless steels and thermoplastics.
In this research work, ample study was conducted on the material characterization of aluminium (Al) and titanium carbide (TiC) metal matrix composites produced via friction stir welding. Different process parameters were employed for the welding process. Rotational speeds of 1600 rpm to 2000 rpm at an interval of 200 rpm and transverse speeds of 100 to 300 mm/min at an interval of 100 mm/min were employed for the welding on an Intelligent Stir Welding for Industry and Research (I-STIR) Process development System (PDS) platform. The process parameters were carefully selected to represent low, medium and high for the rotation and the translation of the tool.
The characterizations carried out include optical microscopy and the scanning electron microscopy analyses combined with Energy Dispersive Spectroscopy (SEM/EDS) techniques to investigate the particle distribution, microstructural evolution and the chemical analysis of the welded samples. Vickers microhardness tests was used to determine the hardness distribution of the welded zone and tensile testing was conducted to quantify the strength of the welded area to the base metal in order to establish the optimal process parameters.
Based on the results obtained from the characterization analysis, it was found that the process parameters played a major role in the microstructural evolution. Homogenous distribution of the TiC particles was observed at high rotational speed of 2000 rpm and low transverse speed of 100 mm/min. The highest hardness value was measured at the stir zone of the weld due to the presence of the TiC reinforcement particles. The tensile strength also increased as the rotational speed increased and 92% joint efficiency was found in a sample produced at 2000 rpm and 100 mm/min. The EDS analysis revealed that Al, Ti and C made up the composition formed at the stir zone. The optimum process parameter setting was found to be at 2000 rpm and 100 mm/min and can be recommended.
M.Ing. (Mechanical Engineering Science)