Effect of hot extrusion and heat treatment on CNTs-Al interfacial bond strength in hybrid aluminium composites

Moderate carbon nanotubes (CNTs-Al) bond strength plays a key role in determining the mechanical and physical properties of the composite. Here, the effect of hot extrusion and heat treatment on the CNTs-Al reaction and their bond state were investigated in SiCw + CNTs/6061Al hybrid composites prepared by squeeze casting. The results show that the reaction activation energy between CNTs and molten 6061Al is slightly higher than that between CNTs and 2024Al. Reaction between CNTs and Al may also happen at temperature below solidus temperature of 6061Al. After the hot-extruded composite was heat-treated at 580 °C for 1 h, the composite shows enhanced tensile strength due to the improvement of interfacial bond strength between CNTs and Al. Fracture surface observation reveals that the improvement of the tensile strength is related to the enhancement of CNTs-Al bond strength. This demonstrates that controllable interfacial reaction may be adopted to introduce moderate interaction layer between CNTs and Al, and thus raise their bond strength.