Role of scandium addition to microstructure, corrosion resistance, and mechanical properties of AA7085/ZrB₂+Al₂O₃ composites

The effect of varying amounts of scandium (Sc) on themechanical performance and corrosion resistance of aluminum alloy (AA7085)composites reinforced with Zirconium diboride (ZrB₂) and Aluminumoxide (Al₂O₃) nanoparticles was investigated. Thespecimens were made using an in-situ process with varying amounts of Sc up to0.5 wt%, and theirmicrostructural behavior, corrosion, and mechanical properties were explored indetail. Phase structural analysis revealed the successful incorporation of ZrB₂ andAl₂O₃ into the matrix through in-situ synthesis,ranging from 30 to 61.7 nm.In addition, HRTEM and XRD analysis displays the Al₃Zr prominenceobserved with 0.1 wt% Sccontent, transforming to Al₃(Sc, Zr) in the 0.3 wt% Sc composite, and finallybecoming Al₃Sc with 0.5 wt%Sc. Corrosion analysis revealed that the 0.3 wt%Sc composite exhibited fine Al₃(Sc, Zr) precipitate phases thatenhanced corrosion properties. The Sc addition leads to a significantimprovement in the mechanical properties of AA7085/ZrB₂+Al₂O₃ composites.The ultimate tensile strength of 678 ± 5 MPafor 0.5 wt% Sc under thehot rolled and T6 aged condition was achieved. The optimum content of Sc inAA7085/ZrB₂+Al₂O₃ composites hasidentified both corrosion and mechanical properties enhancement at 0.3 wt% and 0.5 wt%, respectively.