Mechanical Properties and Corrosion Behavior of Stir Casted Composites of ZA-27 Alloy Reinforced with Al₂O₃ Nanoparticles

Abstract—In this study, the physical, mechanical and corrosion characteristics of ZA-27 alloy reinforced with Al₂O₃ nanoparticles have been investigated. Composites reinforced with three weight fractions (1, 2, and 3%) of Al₂O₃ were synthesized by a double stir casting technique and examined using optical microscopy, micro-Vickers hardness tester and potentiodynamic polarization. Scanning electron microscopy (SEM) equipped with energy dispersive X-ray spectroscopy (EDX) was used to examine surface morphology and identify surface constituent elements of the specimens before and after corrosion. Electrochemical data and morphological analysis were used to explain corrosion behaviors. The synthesized nanocomposites have a porosity content greater than the as-cast alloy and increased with increase of the Al₂O₃ content. The nanocomposites showed smaller dendritic structures as the amount of Al₂O₃ increased, which improved their microhardness numbers. The potentiodynamic polarization test results revealed that the uniform and localized corrosion resistance of the nanocomposites were improved by incorporating Al₂O₃ nanoparticles. Weak micro-galvanic cells form between the constituent phases of the fabricated nanocomposites and it becomes weaker with increasing the Al₂O₃ weight fraction which improves their resistance for the uniform and localized corrosion.