Effect of cold sprayed Al coating on mechanical property and corrosion behavior of friction stir welded AA2024-T351 joint

An aluminum coating was deposited on the surface of a friction stir welded 2024-T351 aluminum alloy joint via cold spraying for corrosion protection. The results show that a relatively dense coating could be formed except some pores on the coating surface layer under certain spray conditions, and the bonding between the coating and the weld surface seems good. Immersion tests in the exfoliation solution confirm that the presence of pure Al coating significantly decreases the corrosion attack. The most important finding is that the tensile properties of friction stir welds are improved after coating deposition. Taking into account the increased microhardness near the joint surface, the shot-peening effect and the release of residual stresses during particles deposition contribute to the improvement of joint tensile strength. Therefore, the combination of these two solid-state processing techniques will generate synergistic effects on the joint performance in service.