Wear Resistance Enhancement of Al6061 Alloy Surface Layer by Laser Dispersed Carbide Powders

In this paper, results of the experimental study on improving wear resistance in sliding friction of Al-based alloy are presented. The technique used involves the formation of a metal matrix composite (MMC) in the alloy surface layer by laser dispersion of carbide powders such as WC, TiC and SiC. For WC and TiC MMC surface coatings fabricated under conditions typical for most of the technologically relevant solid-state lasers (wavelength range of 0.8–1.1 μm), the nearly inversely proportional dependence of the required laser energy density on the powder mass density is observed. Highly homogenous distribution of powder particle content (up to 40%) in the MMC surface coatings of a thickness between 0.8 and 1.6 mm obtained by multiple scanning is observed in the cross-section of specimens processed within a rather narrow parameter window. Tribological tests and comparison to untreated material reveal wear resistance increases by five- and ten-fold, observed in samples with laser-dispersed TiC and WC powders, respectively. Results indicate that substantial modification and reinforcement of the surface layer can be achieved in Al alloy in a one-step process without substrate preheating.