Synergistic Effects of Carbon Nanotubes (CNTs) and White Graphite (h-BN) on the Microstructure and Mechanical Properties of Aluminum Matrix Composites

Abstract

The increased demand for lightweight structural materials in the transport sector has compelled researchers to develop materials with high strength and reduced structural weight, aiming to enhance vehicle performance, minimize fuel and oil consumption and reduce CO₂ emissions. However, their structural weight and strength still need to be improved. Herein, an attempt has been made to fabricate aluminum-based composites reinforced with hexagonal boron nitride (h-BN: 1,3,5,7 wt% ) and multi-walled carbon nanotubes (MWCNTs: 0.25, 0.5, 0.75, 1 wt%) through powder processing method. The results revealed that the 3BN/Al composite disclosed better densification (96.8%) and hardness (49 ± 1.5) among all BN/Al composites. Furthermore, the addition of 0.5 wt% CNTs to BN/Al composite significantly improved the densification (97.7%), Vickers hardness (106%) and tensile strength (189%) over pure Al. This improvement was attributed to homogeneously distributed h-BN and CNTs in the Al matrix and the formation of hard aluminum carbide (Al₄C₃) phase. The results demonstrate that BN/CNTs/Al composite exhibits superior mechanical strength, making them promising structural and functional materials for aerospace and automobile industries.