Investigating the synergistic effects of Zr-reinforcement on the mechanical and corrosion properties of AA2024 alloy

Abstract

This study explores the enhancement of mechanical strength and corrosion resistance in friction stir welded AA2024-T3 joints by incorporating 99.9% purity nano-sized zirconium (<50 nm). Welding was performed using a threaded-taper tool, varying rotational speed (600–1200 r/min) and traverse speed (3–7 mm/s). Optimal properties were achieved at 900 r/min and 3 mm/s, yielding maximum hardness of 203.3 HV_0.1 and UTS of 378.6 MPa (83.20% joint efficiency). These conditions facilitated optimal material flow around the tool pin, ensuring uniform distribution of Zr nano-powder, forming a strong bond between the aluminium matrix and the reinforcement. Corrosion current density decreased by 19.24% (I_corr: 7.12 to 5.75 μA.cm⁻²), enhancing corrosion resistance. These findings highlight the potential of Zr reinforcement for high-strength, corrosion-resistant welded structures.