Abstract Carbon/aluminium (C/Al) composites have the advantages of low density and high electrical conductivity, which have potential applications in aerospace, rail transportation and other fields. However, the unstable bonding of the C/Al interface and significant thermal expansion differences have resulted in risks of the composites' failure once suffering from severe thermal shock. In this work, the C/Al composites were prepared by the pressure impregnation method, and silicon (Si) was added to overcome the problems of C/Al non‐wettability and thermal expansion differences. The effects of mass fractions of doped silicon on the mechanical properties, electrical conductivity and thermal shock resistance of C/Al composites were also examined. Results show that the formed SiC interlayer has effectively enhanced the interfacial bonding and reduced the differences in the thermal expansion coefficient of each component. As a result, the thermal shock resistance of the composites has been remarkably improved, and the flexural strength could remain 90% of the original level after the thermal shock test, compared with 50% of that without Si doping.
