Fracture behaviour of Al2O3/SiC nanocomposite ceramics after crack healing treatment

The self-crack-healing ability was systematically studied using flexural strength measurement of beams containing a semi-elliptical surface crack made by Vickers indenter. Beams of Al2O3/SiC ceramic nanocomposite with a good self-crack-healing ability predetermined for four-point and three-point bend test were prepared by ceramographic techniques. Flexural strength and fracture toughness were determined using three- and four-point bend method. Thermal aging in range from 1000 °C up to 1300  °C for 1 h was applied to find optimal conditions to heal the samples pre-cracked by the indentation technique. Fractographical analyses using an optical and/or scanning electron microscopy has been carried out to investigate the surface crack behaviour. Very good self-crack healing ability has been proved for surface micro-cracks having length up to 250 μm and depth no higher than 100 μm.