X.X. Zhang

Fabrication of aluminum matrix composite reinforced with carbon nanotubes

Abstract 1.0 wt.% carbon nanotube (CNT) reinforced 2024A1 matrix composite was fabricated by cold isostatic press and subsequent hot extrusion techniques. The mechanical properties of the composite were measured by a tensile test. Meanwhile, the fracture surfaces were examined using field emission scanning electron microscopy. The experimental results show that CNTs are dispersed homogeneously in the composite and that the interfaces of the Al matrix and the CNT bond well. Although the tensile strength and the Youngs modulus of the composite are enhanced markedly, the elongation does not decrease when compared with the matrix material fabricated under the same process. The reasons for the increments may be the extraordinary mechanical properties of CNTs, and the bridging and pulling-out role of CNTs in the Al matrix composite.

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 SiCwu2009+u2009CNTs/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 580u2009°C for 1u2009h, 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.