Investigation of the tensile mechanical properties and failure mechanisms of 2D SiC/SiC composites in thermal, mechanical, and oxidation environments

Abstract This study investigates the macroscopic mechanical properties of 2D SiC/SiC composite materials through axial tensile tests conducted at room temperature, 1200°C argon atmosphere, and 1200°C/4kPa oxygen partial pressure. Scanning electron microscopy is employed to analyze the fracture surfaces under varying environmental conditions. The results show significant nonlinear stress-strain curves in all three temperature environments, with a 10% reduction in tensile strength observed at 1200°C in the argon atmosphere compared to room temperature. In the presence of oxygen at 1200°C, a slightly lower tensile strength is accompanied by increased data dispersion. Fracture surface analysis reveals degradation primarily in layering, interface delamination, and long fiber pull-out at 1200°C in the argon atmosphere. Different oxidation mechanisms between the two high-temperature environments lead to more severe interface layer oxidation and shorter fiber pull-out lengths under 1200°C/4kPa oxygen partial pressure.