Brittleness Reduction of Al2O3-C 2 O 3-C Refractories: Microstructure Evolution and Role of Carbon Fibers

Carbon fibers (Cf) f ) were incorporated into Al2O3-C 2 O 3 -C refractories to enhance their toughness in this work. The results indicated the 0.3 wt% Cf-adding f-adding improved the high-temperature bending strength to 1.93 MPa from 1.07 MPa, and led to a 55 % enhancement in thermal shock resistance. The above enhancement could attributed to the in-situ formed SiC coating which was observed on the carbon fiber's surface and strengthened the interface bonding between the carbon fiber and refractory matrix. A solid-liquid diffusion reaction was employed to describe the formation process of in-situ SiC layer on the carbon fibers. Furthermore, the wedge-splitting test with digital images was carried out to investigate the crack-growth trajectory during the splitting process. It was confirmed that Cf-adding f-adding could enhance the strength and reduce brittleness with the crack-bridging, pullout, and interlock behaviors of carbon fibers in the refractory matrix.