Microstructural characteristics and wear properties of Si3N4/ ZrO2 reinforced Al7055 alloy T6 heat treated metal matrix composites

This study focuses on the experimental analysis of the microstructural and tribological properties of silicon nitride (Si 3 N 4 ) and zirconium dioxide (ZrO 2 ) particulates reinforced in heat-treated and as-cast samples of an Al7055 matrix composite. The metal matrix composite (MMC) samples were manufactured using a two-stage stir-casting process. The wear characteristics of both the composite test samples and the T6 heat-treated specimens were evaluated. The Al7055 core alloy and Al7055/ Si 3 N 4 / ZrO 2 composites were processed by maintaining them in a metallic matrix at approximately 500 °C for one hour, followed by immediate quenching in chilled water. The samples were then artificially aged for 1000 h at 180 °C. Microstructural analysis, including Scanning Electron Microscopy (SEM) and X-Ray Diffraction (XRD), was conducted to examine the distribution and dispersion of the reinforced Si 3 N 4 / ZrO 2 particles within the Al7055 composite matrix. The results indicated a significant improvement in wear resistance with the addition of Si3N4/ ZrO 2 particles compared to the as-cast Al7055 alloy. Moreover, the study observed that the mechanical and tribological properties of the Al7055 alloy, as well as the Al7055- Si 3 N 4 / Zro 2 composite, exhibited substantial enhancement following heat treatment. The findings demonstrate that the incorporation of Si 3 N 4 and ZrO 2 particulates into the Al7055 matrix, combined with appropriate heat treatment, leads to a considerable improvement in the material's mechanical properties and wear resistance. This research provides valuable insights into the potential of using these reinforced metal matrix composites in applications where enhanced durability and mechanical performance are critical.