Effect of connection processes on mechanical properties of 7B04 aluminum alloy structures

The static and fatigue properties of 7B04 aluminum alloy structures connected by riveting and refill friction stir spot welding (refill FSSW) were compared and analyzed. Results show that the static compression load of the typical structure connected by riveting and refill FSSW fluctuated in the range of 117–124 kN, and the shear load was in the range of 89–95 kN. Welds spacing had a small influence on the static load of the structures joined by refill FSSW. However, the fatigue life of riveted structures was lower than that joined by refill FSSW. For the welded structure, the heterogeneous microstructures of the welded joint led to the uneven microhardness, and the hook at the lap interface bent upwards at the same time. These factors made the welded structures during the fatigue test failure along the path of sleeve moving.