Study of SiC fiber axial compressive behavior using tensile recoil measurement |
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Authors: | Dexuan Yan Mei Zu Pengren Wang Yu Zhang Jiahui Chen Yanzi Gou |
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Affiliation: | Science and Technology on Advanced Ceramic Fibers and Composites Laboratory, College of Aerospace Science and Engineering, National University of Defense Technology, Changsha, China |
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Abstract: | SiC fibers have been widely investigated as reinforcements for advanced ceramic matrix composites owing to their excellent high-temperature properties. However, the axial compressive strength of SiC fibers has not been thoroughly studied. In this study, the compressive behavior of two SiC fiber types containing different compositions and thermal degradation were characterized by tensile recoil measurements. Results illustrated that the SiC fiber compressive strength was 30%–50% of its tensile strength, after heat treatment at 1200℃–1800℃ for 0.5 h in argon. The fiber compressive failure mechanism was studied, and a “shear-bending-cleavage” model was proposed for the recoil compression fracture of pristine SiC fibers. The average compressive and tensile strengths of the pristine SiC-II fiber were 1.37 and 3.08 GPa, respectively. After treatment at 1800℃ for 0.5 h in argon, the SiC-II fiber compressive strength decreased to 0.42 GPa, whereas the tensile strength reduced to 1.47 GPa. The mechanical properties of the fibers degraded after high-temperature treatment. This could be attributed to SiC grain coarsening and SiCxOy phase decomposition. |
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Keywords: | compressive failure compressive strength fractographic analysis SiC fiber tensile recoil measurement |
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