Effect of friction stir welding on microstructure and mechanical properties of the 6061 aluminium alloy/15vol % SiC_p reinforcement

Abstract In this article, the microstructure and mechanical properties of friction stir-welded joints were evaluated after 15 vol. % of silicon carbide particle (SiCp) were introduced into the joint line, then compared with another welded joint without using SiCp. The rotational speed of 1750 rpm was applied during the friction stir welding (FSW) process. The microstructure was assessed at the stir zone (SZ) using Field Emission Scanning Electron Microscopy (FESEM), and results showed a banded structure of the particle-rich region of SiCp. The ultimate tensile strength (UTS) was enhanced by 79.6 %, due to the presence of SiCp. This strength increased significantly due to the pinning effect and enlarged nucleation sites associated with the SiCp. Furthermore, the reinforced particles induced the fracturing of the primary grains and showed higher ductility when compared with the SiCp-free specimen.