Synchrotron X-ray study of a Ti/SiCf composite during in situ straining

X-ray synchrotron radiography and high spatial resolution strain measurements have been combined to build-up a picture of the micromechanics of the damage that occurs, and the internal stress that causes it, within a Ti/SiC monofilament composite test-piece that was progressively strained in situ on the beam-line. The sample was designed to include a row of fibre ends within the test-piece. The radiographs show that fibre breakages occur during straining, even in the vicinity of the fibre ends. Axial and transverse strain measurements were made along each fibre in the composite as the load was progressively increased using a small X-ray spot size. In the present case interfacial sliding is believed to occur by slipping in or near the 4 μm carbon coating of the SCS-6 fibres. In order to interpret the strain measurements the predictions of a simple axi-symmetric finite element model of the composite are compared with the measured strains.