Optimization of Friction Stir Welding Parameters to Maximize Hardness of AA6082/Si3N4 and AA6082/SiC Composites Joints

Silicon carbide (SiC), Silicon nitride (Si3N4) particles were added in AA6082 to produce aluminum matrix composites (AMCs). Identifying suitable joining process and selecting appropriate parameters is essential for application of these AMCs. Fabricated plates of AA6082/SiC/5 wt.%, AA6082/SiC/10 wt.%, AA6082/SiC/15 wt.% and AA6082/Si3N4/5 wt.%, AA6082/Si3N4/10 wt.%, AA6082/Si3N4/15 wt.% composites were properly welded by friction stir welding (FSW). L9 orthogonal array of taguchi was utilised to design the experiments and optimize the parameters. Effects of tool rotation speed, welding speed, and tool tilt angle on hardness of weld nugget zone of AA6082/SiC composites and AA6082/Si3N4 composites were also investigated. Homogeneous spreading of SiC particles in addition to spherodization of silicon needles and their spreading through matrix were found to be dominant factors for property improvement in stirring zone. It was revealed that the hardness of FSW joints increases because of existence and pining effect of hard Si3N4 particles. It was detected that increase in micro hardness of weld nugget of AA6082/SiC composite was more, as compared to increase in micro hardness of AA6082/Si3N4 composites. Novelty of work is that FSW parameters have been optimized to successfully weld and achieve maximum hardness of AA6082/SiC and AA6082/Si3N4 composites. Findings of this research work will be utilized for FSW of components made of these composites, and to achieve maximum hardness of FSW joints. Such components will be utilized in aeroplanes, satellite, cars and ships.