A380 Aluminum Molten Processing Using Silica-Nanoparticle Enriched Zeolite with Thermal Aging Treatment

Abstract

In this study, Mg was removed from an A332 molten alloy using mixtures of mineral zeolites enriched with 1, 2, and 3 wt.% of amorphous silica nanoparticles (SiO_2NP) to obtain an A380 aluminum alloy. Mineral zeolite with 3 wt.% SiO_2NP was found to be the most efficient mixture, removing Mg from an initial content of 2 wt.% to a final content of 0.046 wt.% 70 min after injection. The results indicated that a decrease in the Mg content, followed by thermal aging treatment (T6) at 150 °C for 10 h, resulted in a reduction of the volumetric fraction percentage (V_f%) of needle-like β-Al₅FeSi intermetallics from 1.123 to 0.181. Similarly, T6 treatment modified the lamellar Si-eutectic to cell-eutectics, as revealed by microstructure analysis. Consequently, the mechanical properties of the alloy, such as fracture strength (σ_f), yield-stress (σ_o), and strain (ε), were improved. The microstructural modification postulated in this study can enhance the contact stiffness under load cycles of 100 Hz at 400 mN, owing to the high storage elastic modulus of 57 GPa, estimated by dynamic mechanical analysis nanoindentation.