Surface Characterization and Comparison of AA2024 Subjected to Multiple Severe Plastic Deformation Techniques

Abstract This study presents a comprehensive comparison of various severe plastic deformation (SPD) techniques: high-pressure torsion, friction stir processing (FSP), accumulative roll bonding, and equal channel angular pressing, in refining the grain structure and enhancing the properties of AA2024 aluminum alloy. Microstructural results confirmed that all SPD methods led to notable grain refinement, with FSP achieving the smallest and most evenly distributed grains. Phase analysis revealed that each technique promoted effective dissolution and reprecipitation of precipitates, along with strain-induced phase transformations. Although a slight reduction in tensile strength was observed due to grain softening, the FSP sample showed a marked improvement in elongation. Corrosion behavior indicated enhanced corrosion resistance for all SPD-treated samples. FSP showed the most positive corrosion potential (Ecorr) and the lowest corrosion current density (Icorr). Wear tests demonstrated that FSP resulted in the least material loss and the lowest coefficient of friction, confirming improved wear performance in all processed variants. Among the SPD techniques, FSP emerged as the most effective in enhancing the mechanical, corrosion, and tribological properties of the AA2024 alloy, making it a promising method for demanding structural applications.