Mechanical property tests of mullite fiber-reinforced SiO₂ aerogel composites

In order to investigate the tensile and interlaminar shear properties of mullite fiber reinforced SiO₂ aerogel composites, related tests were conducted. The in-plane tension tests of the composites were carried out at room temperature firstly, and the in-plane tensile modulus of the composite at room temperature was obtained. Then, the extensometer method and digital image correlation method were adopted respectively to measure the tensile deformations, and the two methods were compared and analyzed. Finally, the interlaminar shear tests at different temperatures were conducted, the interlaminar shear properties of the composites at different temperatures were investigated, and the microstructures were analyzed. The results show that the tension modulus of the composites is about 285.17 MPa. The tensile modulus calculated by the tensile deformation obtained by the extensometer method is 2.4% higher than the tensile modulus obtained by the digital image correlation method. The specimens present obvious interlaminar shear damage at room temperature and high temperature. The microscopic analyses on composites find that SiO₂ aerogel matrix mainly distributes in interlaminar areas and reinforced fibers mainly distributes in plies. The conclusions obtained show that the tensile and interlaminar properties of mullite fiber reinforced SiO₂ aerogel composites are relatively poor, SiO₂ aerogel matrix plays a main role under interlaminar shear load, and temperature has a great influence on the properties of the composites.