Fracture Toughness Testing of Advanced Silicon Carbide Ceramics Using Digital Image Correlation

摘要

The quasi-static fracture toughness (K_(Ic)) of pressureless-sintered and reaction-bonded ceramics was investigated through a four-point bend, chevron-notch testing method. The sample geometry is in accordance with Configuration A of the ASTM C1421 testing standard. Tests were conducted using an electro-mechanical universal testing machine. The digital image correlation (DIC) technique was used to verify stable crack nucleation and growth through recording of the crack mouth opening displacement (CMOD). The reaction-bonded composite displayed a higher K_(Ic) value than the pressureless-sintered ceramic, possibly due to the presence of the silicon phase, which exhibits a quasi-ductile fracture behavior.