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 (Si₃N₄) as a tertiary ceramic alongside boron carbide (B₄C) 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 Si₃N₄ increased hardness by 35.7%, while wear resistance improved by 43.7% with a combined reinforcement of B₄C, Gr, and Si₃N₄ at 18 wt.%. Scanning electron microscopy (SEM) revealed the formation of a mechanically mixed layer (MML) composed of B₄C, Gr, and Si₃N₄, 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.% B₄C, 6 wt.% Gr, and 3 wt.% Si₃N₄. 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.