Enhanced corrosion resistance and mechanical behavior in AA2024-T3 alloy composite via friction stir processing with Zn incorporation

This study focused on enhancing the corrosion resistance of Zn-reinforced, multi-pass friction stir-processed 6 mm AA2024-T3 plates. Influence of FSP passes and Zn microparticle incorporation on composite corrosion behavior in 3.5% NaCl solution. Microstructural analysis was performed using optical microscopy (OM) and field-emission scanning electron microscopy with energy-dispersive spectroscopy (FESEM-EDS). The corrosion behavior was assessed through potentiodynamic polarization and cyclic voltammetry. The results indicated an increased corrosion resistance in the second pass, followed by a reduction in the third pass. This trend aligns with the dissolution of Al2CuMg intermetallics and the formation of corrosion-resistant AlZn and CuZn compounds, as confirmed by the XRD analysis. Grain size analysis reveals substantial reduction in the first and second passes (39.2 mu m to 7.6 mu m and 4.2 mu m, respectively), with no significant change in the third pass. The application of FSP on AA2024-Zn composite enhanced the tensile strength by 31% in comparison to base material due to the uniform distribution of Zn micro particles and grain refinement of aluminum matrix.