Effect of Tool Geometry and Heat Treatment on Friction Stir Processing of AA6061

In this study, AA6061 plates of 6 mm thickness were subjected to friction stir processing with 50% pin overlapping to produce bulk area fine grain structure using three different tool geometries. Post-processing heat treatment was carried for all samples to investigate the effect of different tool geometries on microstructure and micro-hardness of AA6061. 3D optical microscope and Vickers micro-hardness tester were employed to examine the microstructure and micro-hardness, and results have been reported. From an analysis, it was observed that post-processing heat treatment improved the properties and among three different tool geometries, the samples processed with the hexagonal pin profile yield the best results.