Full-field characterisation of oxide-oxide ceramic-matrix composites using X-ray computed micro-tomography and digital volume correlation under load at high temperatures

In situ synchrotron X-ray computed micro-tomography and digital volume correlation (DVC) were utilised to understand the failure mechanisms at room temperature 1050 °C of two Nextel™720/alumina oxide-oxide ceramic-matrix composites (CMCs), termed materials A B, sintered respectively 1200 ~1250 °C. At both test temperatures, three-point-bending strengths ~55–58 MPa for material ~94–100 B. Damage was associated with three primary types cracking modes: interfacial delamination, inclined cracks within fibre tows, opening existing matrix shrinkage cracks. Material exhibited higher cracking, whereas B displayed more pronounced diagonal microcracking. °C, systems showed less microcracking but delamination. Such damage characteristics rationalised in terms corresponding 3D DVC displacement/strain fields. Specifically, global maximum principal strain locations prior failure, which varied from 0.005 0.01, correlated well fracture initiation sites. Further, abrupt positive negative transitions shear components observed attributed different bonding between 0°/90° fibres matrix. The current study demonstrates that high-temperature tomography/DVC is a powerful method studying deformation CMCs.