Curing‐Route‐Dependent Interlaminar Microstructure and Fracture Toughness of MWCNT ‐Reinforced Carbon Fiber/Epoxy Composites

ABSTRACT Conventional thermally cured carbon‐fiber‐reinforced polymers (CFRPs) commonly suffer from low interfacial toughness and high curing energy consumption. This study systematically compares five different curing strategies. It focuses on the relationships among curing routes, interlaminar MWCNT morphology, electrical response, energy consumption, and interlaminar fracture toughness. Interfacial morphology was characterized using SEM, while current–voltage monitoring was adopted to quantify the evolution of electrical resistance and the energy consumption during curing. Mode‐I fracture toughness tests combined with fractographic analysis were further conducted to identify variations in interfacial energy‐dissipation mechanisms. The results showed that pulsed‐current curing (PC) produced more uniform interlaminar MWCNT morphology than oven curing (OVC) and direct‐current curing (DC). It also exhibited more stable electrical responses both with and without a magnetic field. PC decreases curing energy consumption by 95% relative to OVC and by an additional 20% compared with DC, while increasing interlaminar fracture toughness by 11% over OVC. In contrast, applying a magnetic field during DC curing causes pronounced interfacial degradation, reducing interlaminar fracture toughness by 22% relative to OVC. Overall, under PC, the interfacial morphology and mechanical response showed only minor differences before and after magnetic‐field application. In contrast, more pronounced differences were observed under DC.