Exploring the size effects of Al4C3 on the mechanical properties and thermal behaviors of Al-based composites reinforced by SiC and carbon nanotubes

In this work, the effects of aluminum carbide (Al 4 C 3 ) on the mechanical properties and thermal behaviors of Al based composites reinforced by SiC and carbon nanotubes (CNTs) were investigated. The formation of Al 4 C 3 was precisely controlled in the temperature range from 530 °C to 630 °C (80%–95% of the Al melting point) during the post heat treatment. Microscopy observations revealed that Al 4 C 3 rods are originated from CNTs instead of SiC particles. Quantity and size of Al 4 C 3 are highly dependent on the heat treatment temperature. It was found that the mechanical properties of the Al based composites were significantly affected by the size of Al 4 C 3 . Moreover, the formation of Al 4 C 3 helps to decrease the coefficient of thermal expansion (CTE) of the composites due to the consumption of Al and the enhanced interfacial bonding . This study provides a potential approach for ameliorating the mechanical and thermal performances of CNTs reinforced metal matrix composites .