Influence of process parameters on the mechanical properties and corrosion resistance of dissimilar friction stir welded joints of AA2024-O and AA6061-O aluminum alloys

Abstract

Abstract xIn this study, the influence of the process parameters, traverse and rotational speeds, of dissimilar friction stir welded joints of AA2024-O and AA6061-O aluminum alloys on the corrosion resistance was evaluated. Potentiodynamic tests using a 3.5% NaCl solution obtained open circuit potential curves and polarization curves showing the corrosion behavior for the different welding parameters. These data were correlated with those obtained by mechanical tests (microhardness, tensile, and fracture analysis) and microstructure analysis by optical microscopy and scanning electron microscopy. It was observed that the combined effect of the parameters influenced the variation of corrosion resistance. This was mainly evidenced by the improvement in corrosion resistance at 1200rpm − 65mm · min−1 which was related to the recrystallization of the grain size and the heat input presented. Corrosive attacks on the welded joints showed greater affectations in the presence of base material 1 (AA6061-O) with greater metallic dissolution. The attacks mentioned above were presented in different forms, such as pitting, localized, and selective, and were observed by scanning electron microscopy. Finally, in corrosive and mechanical terms, the best performing condition was 1200rpm − 65mm · min−1 compared to the low parameter 840rpm − 45mm · min−1 .