Effect of short carbon fiber content on strength and toughness of Al₂O₃–C refractories

Abstract

Short carbon fiber is a promising candidate for reinforcing carbon‐containing refractories at the macro scale due to its excellent high‐temperature stability and mechanical properties. In this work, the microstructure evolution of short carbon fiber and the effect of its addition on the properties of Al₂O₃–C refractories are investigated. The results show that adding short carbon fiber could affect the distribution of in situ ceramic phases, combined with the cross‐scale reinforcement effect, leading to high strength—the CMOR of short carbon fiber containing refractories could be 23.0% higher than the free ones, while the HMOR could be 22.0% higher. Furthermore, the results suggest that the short carbon fiber containing refractories treated at 1400°C possesses high resistance to the initiation of crack propagation, which could be attributed to the high bonding strength brought by carbon fiber. Noteworthy, adding short carbon fiber could improve thermal shock resistance. The short carbon fiber containing refractories treated at 1300°C could possess a higher residual strength ratio than free ones. For instance, the specimen containing 0.1 wt% short carbon fiber shows the highest residual strength ratio (87.7%).