Improving the mechanical properties of carbon nanotubes reinforced aluminum composites by tailoring the carbon nanotube position and interfacial reaction

In this study, we report a strategy to fabricate high-strength and ductile carbon nanotubes/aluminum (CNTs/Al) composites by embedding CNTs inside CNTs/Al composite powders and lowering the interfacial reaction. The location of CNTs was controlled by the morphology of the composite powder, and further the structure of CNTs was controlled by the sintering temperature. Results showed that the tensile strength of the composites using particulate composite powders increased without sacrificing ductility compared with the composites using flaky composite powders. With decreasing the sintering temperature, the CNT structure was protected and more CNTs existed in the composite instead of Al₄C₃ compound. As a result, the composites with more intragranular and unreacted CNTs registered a high yield strength over 300 MPa and high elongation over 10 %, the combination of which was superior to those in most studies in literature. This study provides a new insight for elucidating powder morphologies and interfaces on mechanical properties, which can be a guidance for fabricating high-performance CNT-reinforced metal matrix composites.