Microstructure and performance of hot-pressed aluminum matrix nanocomposites

Abstract

Al-10 wt% Cu-10 wt% Ni matrix composites reinforced with 0, 10, 15, 20, and 25 wt% silver-coated Al₂O₃ particles were fabricated using hot pressing. The study investigated the effect of Al₂O₃-Ag content on the microstructure, mechanical, tribological, and corrosion properties of the fabricated composites. The composites achieved relative densities exceeding 96%, while X-ray diffraction confirmed the formation of strengthening intermetallic phases, including Al₃Ni, Al₃Ni₂, CuAl₂, and Al₃.₈₉₂Cu₆.₁. The hardness increased from 95.31 HV for the unreinforced alloy to 451.59 HV at 25 wt% Al₂O₃-Ag, representing an approximately 374% increase. The compressive strength increased from 147.59 to 169.02 MPa, representing an improvement of approximately 14.5%, while the maximum compressive strain remained approximately 0.70 mm/mm. The wear rate decreased from 4.2 to 0.88 mg/min, corresponding to an approximately 79% reduction. In contrast, increasing the Al₂O₃-Ag content progressively deteriorated the corrosion resistance, with the corrosion rate increasing from 0.00093 to 0.09596 mm/y in 3.5 wt% NaCl solution. Overall, increasing Al₂O₃-Ag content improved hardness, compressive strength, and wear resistance, while reducing corrosion resistance.