Enhancing Al-16Si-4Cu Alloy Properties Through Heat Treatment and FMRR: A Comprehensive Study on Coating Microstructure and Wear Resistance

This study examines the microstructural and mechanical properties of A390 aluminum alloys treated with fast multiple rotation rolling (FMRR), focusing on the effects of solid solution treatment and heat input on the morphology of Si particles, grain structure, and precipitate behavior. Optical microscopy reveals varying morphologies of primary and eutectic silicon phases, where severe plastic deformation through FMRR fragments and redistributes these particles near the coating surface. FMRR-treated samples at low heat input show refined Si particles averaging 8.2 ± 0.9 µm, while higher heat input slightly increases particle size to 9.5 ± 0.8 µm. Nanoindentation tests indicate that solid solution treatment followed by FMRR at low heat input results in the highest nanohardness (10.65 ± 0.40 GPa) and elastic modulus (232.1 ± 2.9 GPa) attributed to optimal grain size and Al₂Cu precipitate distribution. Additionally, this coating demonstrates a 70% reduction in wear rate compared to the AA1050 substrate, highlighting its enhanced wear resistance.