Sharath, B.N.Mahesh, V.Mahesh, V.Kattimani, S.Harursampath, D.2026-02-032025Proceedings of the Institution of Mechanical Engineers, Part L: Journal of Materials: Design and Applications, 2025, 239, 11, pp. 2053-206714644207https://doi.org/10.1177/14644207241304279https://idr.nitk.ac.in/handle/123456789/19994This study explores the impact of reinforcing an Al2090 matrix with silicon nitride (Si<inf>3</inf>N<inf>4</inf>) as a tertiary ceramic alongside boron carbide (B<inf>4</inf>C) and graphite (Gr) to improve wear resistance at elevated temperatures. Hybrid composite samples were produced using the stir-casting technique. Experimental results show that incorporating Si<inf>3</inf>N<inf>4</inf>increased hardness by 35.7%, while wear resistance improved by 43.7% with a combined reinforcement of B<inf>4</inf>C, Gr, and Si<inf>3</inf>N<inf>4</inf>at 18 wt.%. Scanning electron microscopy (SEM) revealed the formation of a mechanically mixed layer (MML) composed of B<inf>4</inf>C, Gr, and Si<inf>3</inf>N<inf>4</inf>, which acted as an effective insulating barrier, protecting the sample surface from the steel disc. A noteworthy 69% of wear resistance improvement was accomplished at 300 °C for the composite with 9 wt.% B<inf>4</inf>C, 6 wt.% Gr, and 3 wt.% Si<inf>3</inf>N<inf>4</inf>. Atomic force microscopy (AFM) analysis further indicated enhanced surface properties for this composition. These findings highlight the potential of this hybrid composite for high-temperature aerospace applications, such as in engines, heat shields, and structural components. © IMechE 2024Aluminum compoundsAluminum graphite compositesBoron carbideCeramic matrix compositesHeat shieldingHybrid compositesIII-V semiconductorsRockwell hardnessSilicon carbideCasting techniquesCeramics particlesComposite samplesElevated temperatureHigh temperature wear behaviormatrixMechanically mixed layersScanning electronsStir castingSilicon nitride