Dry-Sliding and Seawater Tribological Response of W-and Y-Modified Fe₃Al-Based Alloys

Abstract Selecting Fe₃Al-based alloys for sliding applications requires an understanding of how tungsten (W) and yttrium (Y) additions affect wear under both dry and seawater conditions. Here, Fe–28Al–5Cr alloys containing 0.5, 1.0, or 1.5 at.% W, with or without 0.1 at.% Y, were produced by vacuum arc melting and evaluated by ball-on-disc testing against AISI 52100 steel at 5 N, 0.05 m s⁻¹, and sliding distances of 100–500 m. Wear volume, specific wear rate, friction, microhardness, and worn-surface evolution were examined by profilometry, optical microscopy, x-ray diffraction, and scanning electron microscopy with energy-dispersive x-ray spectroscopy. Fe–28Al–5Cr–0.5W–0.1Y provided the most favorable overall response in both environments, combining low wear with comparatively limited visible cracking and broader Al/O-rich coverage in the examined worn regions. Seawater reduced friction, while post-test surfaces showed heterogeneous O-rich regions and localized Cl, Na, and Mg signals. These observations describe an environment-dependent surface response; quantification of corrosion-related material loss requires electrochemical measurements and separate control tests. The results identify a favorable composition within the tested series, while the relative roles of bulk microstructure and tribo-oxide formation or retention in the Y-associated response remain unresolved.