Cansas-II SiC_f/SiC 复合材料的高温拉伸蠕变行为

Continuous silicon carbide fiber reinforced silicon carbide composite (SiC_f/SiC) is a key material for the advanced aero-engines. It is required to possess excellent high-temperature creep resistance for SiC_f/SiC to meet the long-term service lifetime of the aero-engines. Here, tensile creep behaviors of a plain woven Cansas-II SiC_f/SiC (2D-SiC_f/SiC) were investiged in the temperature of 1200–1400 ℃ with the stress levels of 80 to 140 MPa. Its microstructure and fracture morphology were observed, and composition was analyzed. Results show that creep-rupture time of 2D-SiC_f/SiC is more than 500 h and steady-state creep rate is 1×10^–10–5×10^–10 /s at stresses lower than the proportional limit stress (σ_PLS). The creep behaviors are controlled by matrix and fibers. The creep-rupture time is significantly reduced, and the steady-state creep rate is increased by an order of magnitude when the stress is higher than the σ_PLS. The matrix, fibers and interfaces of the composite are greatly oxidized, and the creep behaviors are mainly controlled by the fibers.