Influence of fiber architecture on the fracture behavior of C _f ‒ZrB ₂ ‒SiC UHTCMCs: A 3D image analysis

Abstract The effect of fiber architecture in two‐dimensional C f ‒ZrB 2 ‒SiC composites on fracture behavior has been investigated with an emphasis on crack propagation mechanisms. The crack patterns generated by three‐point bend tests on notched specimens have been examined by a three‐dimensional X‐ray microscope. Regardless of fiber architecture, the cracks initiated from the notch have exhibited mixed mode propagation with fiber pull‐out and gradual closure on approaching the compressive end of specimens. The UD‐0/0° composite with the highest work of fracture (∼2032.7 J/m 2 ) has exhibited thick cracks with a moderate surface area but the highest volume. In contrast, the cracks in the UD‐0/90° composite with the lowest surface area and volume have followed a linear path through the 90° laminae. The interlaced fiber architecture of the 8‐harness satin‐woven (8H‐SW) composite has exhibited a crack pattern with large surface area and moderate volume with compressive buckling of fibers, effectively restricting the lateral crack propagation.