Research on fatigue failure of SiCf/SiC composites at high temperature based on X-ray computed tomography

作者：Teng, Xuefeng; Zhu, Kewei^*; Jia, Jie; Tian, Feiyu; You, Junjie; Zeng, Qi; Luo, Xiao; Wang, Wenjun; Cao, Xueqiang; Li, Longbiao; Hu, Xiaoan^*

来源：Ceramics International, 2023, 49(24): 40541-40550.

DOI：10.1016/j.ceramint.2023.10.032

• SiC f /SiC composite
• X-ray computed tomography
• High-temperature fatigue
• Stitching hole

The woven architecture of ceramic matrix composites and the existence of pores lead to the anisotropy and non-uniformity of the materials, which affect the mechanical behavior and failure of the materials in service environment. In this paper, tension-tension fatigue behavior of a plain-woven SiCf/SiC composite was investigated via X-ray computed tomography. The mesoscale architecture (pore, woven, etc.) characteristics of the SiCf/SiC specimen were obtained by X-ray computed tomography before and after the tests, and the conclusions can be drawn as following: (1) Changes in hysteresis loops, elastic modulus and area of hysteresis loop are correlated: as the cycle number increases, the elastic modulus decreases and the area of hysteresis loop increases; The larger the area of hysteresis loop, the greater the decrease rate of elastic modulus. (2) the porosity distribution of SiCf/SiC specimen shows the characteristics of both periodic and aperiodic. The periodic phenomenon is related to the mesowoven architecture, while the aperiodic phenomenon is caused by the distribution of stitching holes. (3) The fracture location of the specimen is significantly affected by the location of the stitching holes and the porosity distribution, but not completely determined by them. (4) When the load on the specimen is large, the stepped cracks are more likely to occur, and most cracks initiate from the surface/boundary of the fiber.

• 单位
  南昌航空大学; 南京航空航天大学; 武汉理工大学