Interfacial shear strength and fracture toughness between single carbon fiber and TiO₂ matrix under microbond test

ABSTRACT

To improve the interfacial adhesion between reinforcement and matrix in carbon fiber-reinforced composites, TiO₂-coated carbon fibers are used to protect the fiber against degradation. Accordingly, it is crucial to assess the interfacial properties of carbon fiber–TiO₂ interface. In this study, single carbon fiber–TiO₂ systems were prepared through curing at different temperatures. Subsequently, the shear strength and fracture toughness of the cured single carbon fiber–TiO₂ interfaces were investigated through microbond test, and the effect of the curing temperature on them was discussed in detail. The results show the interfacial shear strength and fracture toughness of the single carbon fiber–TiO₂ systems witness a significant improvement due to the volume shrinkage of TiO₂ matrix and the cured pits on carbon fiber after high-temperature curing, especially for the system cured at 750°C, whereas the cross-linking between carbon fiber and TiO₂ matrix through surface functional groups is a main contributor for the interfacial behavior of the system cured at 80°C. Finally, the failure mechanisms of the carbon fiber–TiO₂ interface were investigated. The interfacial separation is considered a main failure mode both at curing temperature of 80°C and 750°C.

KEYWORDS:

• Carbon fiber
• composites
• interfaces
• cohesion
• shear strength
• fracture mechanics

Acknowledgements

This work was supported by the Fundamental Research Funds for the Central Universities (China University of Mining and Technology) (2017XKQY011).

Compliance with ethical standards

Conflict of interest: The authors declare that they have no conflict of interest.

Additional information

Funding

This work was supported by the Fundamental Research Funds for the Central Universities (China University of Mining and Technology) [2017XKQY011].