State-of-the-Art Carbon-Nanotubes-Reinforced Copper-Based Composites: The Interface Design of CNTs and Cu Matrix

Carbon nanotubes (CNTs)-reinforced copper-based composites (CNT/Cu) have been extensively investigated due to their exceptional theoretical electrical, thermal, and mechanical properties. However, the actual performance of these composites has consistently fallen short of theoretical expectations. This discrepancy primarily arises from the inability to achieve direct chemical bonding between copper and carbon nanotubes or to alloy them effectively. Consequently, this leads to interference in electron and phonon transmission at the interface between the two materials, adversely affecting their electrical and thermal conductivity as well as other properties. In recent years, research has increasingly focused on optimizing and regulating the interfacial interactions between carbon nanotubes and the copper matrix to enhance overall performance while also exploring potential applications. This article reviews recent advancements from an interface regulation perspective, summarizing typical interfacial characteristics such as physical interfaces, chemical bonding, and metallurgical bonding along with their respective preparation methods and effects on performance enhancement. Furthermore, a novel microstructural design of CNT/Cu is put forward, where amorphous CNTs (aCNTs) were utilized as the reinforcing phase to form a nanoscale networked composite interface. This not only enables Cu to adhere to the aCNTs' sidewall but also fills the sidewall within them, with the aim of significantly strengthening the interfacial bonding strength of CNT/Cu and achieving comprehensive improvement of the composite material properties.