Effect of friction surfacing on the microstructural and wear characteristics of Al-Cu-Mg alloy coating reinforced by nickel aluminide

Abstract

This study investigates the microstructure, mechanical, and tribological properties of the AA2024-Al3NiCu composite coating fabricated by the friction surfacing process on the AA2024 substrate. The findings indicated that increasing the mechtrode's nickel concentration from 0 to 3 wt% reduced the coating's thickness from 1.43 ± 0.05 to 1.21 ± 0.02 mm and its width from 22.3 ± 0.90 to 19.5 ± 0.95 mm. There was no noticeable difference in the grains, precipitates, and intermetallic particles size at different parts of the coating. The size and fraction of the S-Al2CuMg precipitates decreased by increasing the nickel content in the mechtrod from 0 to 3 wt%. Adding 4.5 wt% nickel to the mechtrod formed T-Al6CuMg4 precipitates instead of S-Al2CuMg precipitates. The modulus strengthening mechanism was the main factor in strengthening AA2024-Al3NiCu composite coating when the nickel content was less than 3 wt%; however, the precipitation strengthening mechanism was dominant at higher percentages of nickel. Relative to the AA2024 substrate, enhancing the nickel concentration up to 3 wt% resulted in a 37% reduction in the wear rate.