On enhancing the high-temperature wear behaviour of Al2090-based hybrid composites using tertiary ceramic particles

Abstract

This 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 2024