Effect of matrix microstructure on micro- and macro-mechanical properties of 2.5D woven oxide fiber reinforced oxide matrix composites

A comprehensive learning of the mechanical behavior change mechanism of oxide/oxide composites is of great significance as a guide for their industrial applications. This study focused on examining how matrix microstructure impacted the micro- and macro-mechanical properties of the composites mainly by nanoindentation tests, macro-mechanical tests and x-ray computed tomography. The results showed that the sintering phenomenon of matrix sintered at 1200 °C was more obvious, and there were visible transverse and longitudinal cracks. The in-situ modulus of matrix and interfacial shear modulus of the composite increased by 61.1 % and 36.4 %, respectively, with the increase of matrix sintering densification. Combined with these micro-mechanical parameters of the composites, the He-Hutchinson model predicted the same crack propagation modes as those obtained from fracture toughness tests. Moreover, more matrix cracks directly led to a 45.4 % reduction in the flexural strength of the composites sintered at 1200 °C compared to that sintered at 1100 °C. In addition, a comparison analysis was conducted on the evolution of microstructure, micro- and macro-mechanical properties of 2.5D and 2D composites with the same preparation parameters.