Determination of interfacial fracture energy of an environmental barrier coating on ceramic matrix composite substrate

The present work concerns the study of the interface fracture energy between a SiC/SiC Ceramic Matrix Composite and an environmental barrier coating. Four-point flexural tests with no precrack were conducted. These tests enable for the stable propagation of two interfacial cracks. They were carried out at room temperature and were instrumented with visible light cameras. This instrumentation allowed for the analysis of the tests thanks to digital image correlation as well as comparisons between experimental and numerical results to locate crack tips and to calculate the interface fracture energy using numerical methods based on linear elastic fracture mechanics. The limits of the method as well as the uncertainties associated with the crack length and the fracture energy were assessed.