Microstructural and mechanical response of SiC and TiO2 particles reinforced friction stir welded AA7075 and AA2024

The main objective of this study is the microstructure and mechanical properties of AA7075 and AA2024 welded joints when friction stir welded with different reinforced materials (SiC and TiO2). The imperfection-free welds are portrayed by great mechanical blending between AA7075 and AA2024 and good, reinforced material dispensation in the stir zone. Grain refinement of weld with reinforced material is compared with weld without reinforced material. It is also observed that double-pass processed welds have coarser microstructure than a single pass. Scanning electron microscopy is used to analyze the size and distribution of reinforced particles in the various zones of the weld. The maximum tensile strength of the joint produced with SiC reinforcement particles is 206 MPa, while the minimum tensile strength (177 MPa) was observed without reinforcement particles. A comparative study has been carried out between the friction stir welding of AA7075 and AA2024 with TiO2 and SiC reinforced material and with unreinforced material. The nanoparticles disperse within the weld zone, leading to a refined microstructure and preventing the formation of detrimental defects. This dispersion improves load-bearing capabilities, effectively increasing the tensile strength of the joint. The nanoparticles contribute to a more uniform distribution of stresses and help mitigate crack initiation and propagation. The average hardness value at the stir zone with SiC and TiO2 nanoparticles was observed as 172 HV and 164 HV, respectively, while the minimum hardness value of 147 HV was observed without nanoparticles.