Investigation of AA2014-nAl2O3 Nanocomposites Manufactured by SUS Technique: Parameter Optimization and Corrosion Resistance Enhancement

Abstract The fabrication of aluminum metal matrix composites (AMMCs) plays a pivotal role in determining their suitability for marine applications, where materials are subjected to harsh environments, including saltwater exposure, high humidity, and fluctuating mechanical loads. Poor particle dispersion, agglomeration, and inadequate bonding between the matrix and reinforcements often result in localized corrosion, reduced wear resistance, and structural degradation, making conventional AMMCs less reliable in marine settings. The presence of defects such as porosity and uneven reinforcement distribution further compromises their mechanical integrity and long-term durability under corrosive marine conditions. To overcome these challenges, this study employed an innovative stir-ultrasonication-squeeze (SUS) casting technique to enhance the microstructural and corrosion properties of AA2014-nAl ₂ O ₃ nanocomposites. Critical process parameters, including ultrasonic power (2250 W), ultrasonication time (16 minutes), pouring temperature (700 °C), squeeze pressure (150 MPa), and reinforcement content (2 wt.%), were systematically optimized to achieve uniform particle dispersion, grain refinement, and enhanced corrosion resistance. Advanced characterization using high-resolution scanning electron microscopy (HR-SEM) and optical microscopy (OM) revealed the mitigation of particle clustering and a refined grain structure with a minimum size of 43 µm under optimized conditions. Taguchi grey relational analysis (TGRSA) identified the influence of process parameters on corrosion performance, with ANOVA showing ultrasonication time as the most significant factor (11.5% contribution). Confirmation tests demonstrated optimal process conditions—2.248 kW ultrasonic power, 15.89 minutes ultrasonication time, 700.1 °C pouring temperature, 143 MPa squeeze pressure, and 1.95 wt.% reinforcement—leading to significant improvements in corrosion resistance, including a 14% reduction in salt spray corrosion rate and a 37% increase in grey relational grade (GRG). These findings underscore the potential of the SUS casting technique to address the traditional limitations of AMMCs, providing a pathway for developing corrosion-resistant materials tailored for marine and other extreme environmental applications.