Experimental Study On Mechanical Property Of 2-D Woven C/SiC Ceramic Matrix Composites

2D woven C/SiC ceramic matrix composite is a new kind of high temperature structure material developing in aviation and aerospace field. On the one hand, it has many advantages such as low density, good heat-resistibility and capability of heat stabilization, etc; on the other hand, it overcomes the brittleness of singular ceramic and has high fracture toughness. 2D woven C/SiC ceramic matrix composite has potential for wide application. In recent years, significant progress has been made on chemical vapor infiltration (CVI) technique in China. However, it is necessary to research the mechanical property of CVI 2D woven C/SiC ceramic matrix composite and its component because of the anisotropy, asymmetry and discontinuity of this material, and also of the difference of each process technique.The tension and fatigue property of CVI 2D woven C/SiC ceramic matrix composite at room and high temperature, and the tension, compression fatigue property of its open-hole component were investigated by large amount of tests in this paper. The damage mode and failure mechanism of 2D woven C/SiC ceramic matrix composite and its component under different loadings were also analyzed by fractography.It is showed that the responses of 2D woven C/SiC ceramic matrix composite under tensile loading at both room and high temperature are nonlinear. The tensile strength and failure strain at room temperature are lower than at 1300 ℃ in argon, respectively, but higher than at 1300℃ in air. The changes of the unloading modulus, residual strain and loop width versus tensile stress all can describe the damage of the material under tension; The fatigue properties of 2D woven C/SiC ceramic matrix composite are comparatively well at both room and high temperature, but have large disparity, being dependent on the temperature and fatigue stress level; The responses of the open-hole component under tension are still nonlinear, but linear under compression when the stress is low, changing non-linear when the stress is a little higher because of crack closing. The open-hole component is scarcely sensitive to the open-hole.The fractographic analysis shows that the fractograph of 2D woven C/SiC ceramic matrix composite are very similar under tensile loading at room and high temperature, but have a little difference between the fiber pull-out length and the fractograph uniformity. Matrix cracking, delamination around bundle, fiber/bundle fracture and pull-out are main damage mode and failure mechanism of it; The fractograph of open-hole component under tension is uniform, just a little portion of fibers pulling out and the pull-out length is short. Matrix cracks and fiber tensile fracture are the most failure mechanism of it. The compression failure is in a shear plane a little angle to the loading direction. Delamination , longitudinal fiber shear fracture and matrix craking around longitudinal fiber but little latitudinal fiber fracture are the most failure mechanism of compression. The fractograph of open-hole component are comparatively similar under tensile and fatigue loading.