Interfacial in-situ Al₂O₃ nanoparticles enhance load transfer in carbon nanotube (CNT)-reinforced aluminum matrix composites

Dissatisfactory load transfer has been a critical issue in carbon nanotube (CNT)- and graphene-reinforced metal matrix composites (MMCs) mainly because of the intrinsically unpleasant carbon-metal interfaces. Here we show by introducing in-situ Al₂O₃ nanoparticles at aluminum (Al)-CNTs interface, the load transfer efficiency can be noticeably enhanced in powder metallurgy CNTs/Al composites. From in-situ tensile tests, the nanoparticle-modified Al-CNTs interfaces result in CNT fracture, a sign of high load transfer efficiency; while clean interfaces without nanoparticles lead to CNT pulling-out. The nanoparticle-induced enhancement of interface strength can be explained by the increased sliding resistance of CNTs in MMCs at the wake of cracks under tensile loading. Our study provides a new strategy for designing strong carbon-metal interfaces to fabricate high-performance nanocarbon-reinforced MMCs.