Microstructural transition from ZrO₂ to Zr–Al intermetallics and property evolution in AA5051 composites
G. Anbuchezhiyan, G. Ananth, M. Vignesh, K. Logesh, Nabisab Mujawar Mubarak, Elango Natarajan
Abstract
AA5051 is lightweight and has excellent corrosion resistance, but it loses strength at higher temperatures as magnesium atoms diffuse more readily within the aluminium matrix, reducing the uniformity of the solid solution and weakening the alloy's strengthening mechanism. Incorporating ZrO 2 addresses these challenges by refining the grain structure, generating thermally stable secondary phases, and minimising diffusion processes which influence mechanical properties at elevated temperatures. In the current scenario, ZrO 2- reinforced AA5051 alloy composites were synthesised by the squeeze casting process, and its microstructure and mechanical characteristics were analysed for high-performance components. Microstructural observations show that ZrO 2 particles distribute evenly throughout the alloy matrix without yielding residual pores, and they thrive as nucleation sites during solidification to inhibit recrystallisation. The tensile (24.12 ± 0.01%), compressive (22.55 ± 0.02%), flexural (21.42 ± 0.01%), and impact (32.39 ± 0.01%) characteristics are enhanced by good interfacial bonding, better stress distribution and increases in dislocation density between the intermixture. Al 2 O 3 forms on the alloy surface with the aid of ZrO 2, and it functions as a protective barrier against corrosion and further oxidation. The inclusion of hard ZrO₂ particles minimised wear loss percentage in synthesised composites by reducing direct contact between the matrix and wear surface, resulting in less adhesive wear.