Fabrication of Al-CNT composite with high hardness and electrical conductivity by controlling Al4C3 formation

In this study, an Al-carbon nanotube (CNT) composite with a high hardness of 1.4 GPa and an electrical conductivity of 1.52 x 107 S/m is achieved simultaneously using bare Al nanopowder as a metal matrix. Using bare Al nanopowder, (1) highly dispersed CNTs can be realized because the size of the Al nanopowder is similar to that of the CNTs, and (2) the interface between Al and CNT (Al/CNT interface) can be controlled because of the less oxide layers on the Al particle surface. In particular, fine Al4C3 grains are formed at the Al/CNT interface via annealing at a low temperature of 663 K, which enhances the hardness of the Al-CNT, whereas the remaining Al/Al interface with less oxide layers preserves the electrical conductivity. In con-clusion, the Al-CNT composites prepared in this study overcome the trade-off relationship between the hardness and electrical conductivity of the previously reported Al-nanocarbons. The electrical conductivity of the Al-CNT composites in this study is 33 times higher than that of Al-nanocarbons with the same hardness level.(c) 2023 Elsevier B.V. All rights reserved.

Automated summary

In this study, a high hardness of 1.4 GPa and electrical conductivity of 1.52 x 107 S/m are achieved in an Al-carbon nanotube (CNT) composite using bare Al nanopowder as a metal matrix. The highly dispersed CNTs and controlled Al/CNT interface are achieved due to the similar size of Al nanopowder and less oxide layers on the Al particle surface. Fine Al4C3 grains formed at the Al/CNT interface enhance the hardness while the remaining Al/Al interface preserves the electrical conductivity. The electrical conductivity of the Al-CNT composites in this study is 33 times higher than that of Al-nanocarbons with the same hardness level.