Regulation of interface between carbon nanotubes-aluminum and its strengthening effect in CNTs reinforced aluminum matrix nanocomposites

Carbon nanotubes (CNTs) are popular as the chosen reinforcement to achieve excellent mechanical and functional performance in aluminum matrix nanocomposites (AMNCs). However, the key bottleneck problems restrict the strengthening effect using CNTs in AMNCs due to the dispersion homogeneity of CNTs, the distinct differences in physical properties, poor wettability and interface bonding between CNTs and aluminum matrix. This study aims to address these key issues by introducing a continuous SiC nano layer on CNTs surface synthesized from carbon-silicon reaction, acting as a compatibility transition layer prior to mixing with aluminum powders. The results clearly show that the SiC cladding layer provides a good wettability and strong interfacial bonding between CNTs and aluminum matrix, and the interfacial reaction between CNTs and aluminum matrix could be effectively regulated. It is also conducive to reducing the mass density difference and specific surface energy, improving the dispersion of CNTs in matrix. Those factors make a strong contribution to the strengthening effect of CNTs enforcement by achieving high load transfer efficiency. The AMNCs reinforced by this new CNTs/SiC composite powder show clear improvement of mechanical performance without compromising in ductility and electrical conductivity, as compared to AMNCs reinforced by only CNTs or SiC.