Effect of preform structures on creep properties for SiC_f/SiC composites at 1300 °C in wet oxygen

Creep properties of SiC_f/SiC composites prefabricated from four different preforms (2D plain, 2D satin, 2D plain/satin, and 3D four-directional) by CVI methods were tested at 1300 °C in wet oxygen (12 kPa H₂O, 8 kPa O₂and 80 kPa Ar) under a stress level of 160 MPa. Samples differing solely in preform structures exhibited significant differences in creep lifetime, with the 2D plain sample demonstrating the best comprehensive performance, exhibiting a lifetime of 98 h. The 2D satin composite showed a considerably shorter creep life of 26.5 ± 1.5 h, while the 2D plain/satin sample exhibited a further reduced creep life of 9.8 h. Despite possessing the highest high-temperature tensile strength, the 3D four-directional sample demonstrated a markedly shorter creep lifetime of only 3 h, markedly lower than its 2D counterparts. Notably, compared to plain weave composites, the 2D plain/satin sample exhibits high-temperature creep resistance characteristics that are more closely aligned with those of 2D satin composites. This study is of reference value for the subsequent practical application of related materials.