Tensile behavior and deformation mechanisms of SiC twill woven fabric at room temperature and high-temperature oxidation environment

SiC woven fabrics are promising candidates for flexible thermal protection materials due to their excellent oxidation resistance and mechanical properties at high-temperatures. The uniaxial tensile tests for SiC twill woven fabric were conducted on the fabric in its as-received state and after 1200 °C high-temperature oxidation treatment. A mesoscale constitutive model, based on yarn strain energy, is developed to predict the specific stress-strain response of the fabric. The constitutive model can accurately predict the mechanical behavior in as-received and treatment states, which is also used to clarify the failure mechanisms of SiC twill fabric in extreme thermal environments further. The as-received fabric exhibits the straightening-then-fracture ductile behavior, which is dominated first by yarn bending stiffness during decrimping process. The deformation mechanism of the fabric after high-temperature oxidation treatment transitions to the fracture-before-straightening brittle behavior due to fiber embrittlement and inter-fiber adhesion. The effects of yarn specification, degree of fiber adhesion and fabric geometric parameters on the mechanical behavior of fabric are studied, which can be helpful of design of advanced flexible thermal protection materials.