Effect of High Temperature Treatment in Ar Atmosphere on the Tensile Strength and Structure of SiC Fiber

摘要

The properties and structure changes of SiC fiber in high temperature determine the service temperature of the reinforced ceramic matrix composites, so the properties of SiC fibers under high temperature are very important. The SiC-A and SiC-B fibers were treated at 1200, 1350 and 1600°C in Ar atmosphere. Then the tensile strength was measured, the microstructure and composition of the fibers were analyzed by SEM, EDS, XRD and AES. The results show that the tensile strength of SiC-A and SiC-B decrease slowly at 1200 and 1350°C, but decrease rapidly at 1600°C. The tensile strength of SiC-B fiber decreases less slowly than that of SiC-A fiber. The grain size and the C-enriched region thickness of SiC-A and SiC-B fibers have little change under 1200 and 1350°C, but increase quickly at 1600°C. The decrease of the tensile strength of SiC-A and SiC-B fibers is mainly related to the growth of P-SiC grains.