Microstructure, mechanical properties, and corrosion behavior of 6061 Al alloy prepared by cold spray-friction stir processing composite additive manufacturing

Bulk 6061 aluminum (Al) alloy was prepared by cold spray-friction stir processing composite additive manufacturing (CFAM). The microstructures of the cold sprayed (CS) and CFAM samples were characterized by OM, SEM and EBSD, and their mechanical properties and corrosion behavior were investigated by microhardness, tensile and corrosion tests. The results show that, compared with the CS sample, the microstructure of the CFAM sample is densified and homogenized. The grains are small and equiaxed with an average grain size of 3.1 mu m. The microhardness, ultimate tensile strength, and elongation of the CFAM sample are increased by 22%, 171%, and 683%, respectively. The corrosion current density of CFAM sample is 95.1%-97.8% lower than that of CS sample, and the corrosion mechanism is changed from pitting corrosion of CS sample to intergranular corrosion.