Unlocking the high strengthening efficiency of single-walled carbon nanotubes in Al matrix composites via strong interfacial bonding

Single-walled carbon nanotubes (SWCNTs) possess super-high strength and large specific surface area, which are ideal reinforcements for metal matrix composites. However, studies related on SWCNTs/Al nanocomposites are limited and the reported strengthening efficiencies of SWCNTs are usually low. In this study, friction stir processing (FSP) was employed to fabricate Al matrix composites reinforced with SWCNTs. Microstructural characterizations revealed that SWCNTs were well dispersed into Al matrix. Significantly, the unique thermo-mechanical conditions inherent to FSP facilitated the formation of direct, intimate SWCNTs/Al interfaces devoid of cracks or visible interfacial gaps. These optimized interfacial characteristics resulted in exceptional strengthening efficiency (⁓84), yielding nanocomposites with a strength double that of the unreinforced Al. This study provides new insight into developing SWCNTs/Al nanocomposites with high performance.