This study explored friction stir spot welding (FSSW) of Al6061-T6 and copper alloys with silicon carbide (SiC) particle reinforcement. The impact of these particles and process parameters on metallurgical and mechanical properties was examined by assessing intermetallic layer thickness and temperature increase. Results showed that SiC particles increased the intermetallic layer thickness by 9.52%, enhancing the properties of the welded joints. Cross-sectional analysis was done using scanning electron microscopy (SEM) and energy dispersive spectroscopy (EDS) confirmed the presence of SiC particles in the weld. Additionally, Al4Cu9, Al2Cu, and α-Al phases were detected in welds without SiC reinforcement, whereas Al4Cu9 was absent in welds with SiC particles. This suggests that SiC particle reinforcement not only improves mechanical properties but also alters the development of intermetallic compounds in the welded region.