t.J. Appl Ceram. Technol.,8/2/308-316(2011) DO:10.I116.1744-7402.2010.02588 International Journal o pplied Ceramic TECHNOLOGY ceramic Product D Microstructure and Mechanical Properties of SiC and Carbon Hybrid Fiber Reinforced SiC Matrix Composite Shanhua Liu, Litong Zhang, Xiaowei Yin, Laifei Cheng, and Yongsheng Liu Naidongiy, a m, shanxi 710072, Pepl e composite Materials, Northwestern Polytechnical Silicon carbide(SiC) matrix composite reinforced by both SiC and carbon fibers([SiC-C]/pyrolytic carbon [Py C]/SiC) was fabricated by chemical vapor infiltration for reducing matrix microcracks. Microstructure, mechanical properties, and oxidation resistance of the composite were compared with those of C/PyC/SiC and C/PyCH /SiC composites in which PyC interphase was untreated and heat-treated at 1800.C in argon, respectively. Compared with the C/PyC/SiC C)/PyC/SiC composite shows considerable improvements in Flexural strength, fracture toughness, and oxidation resistance The different mechanical behaviors of the three composites were analyzed based on the He and Hutchinson's model Introduction vanced thermostructural materials for use in the aero- space industry, owing to their low density, excellent Silicon carbide(SiC)matrix composites reinforced thermal-shock resistance, and high mechanical proper with carbon fiber(C/SiC)and silicon carbide fiber(Sic/ ties at high temperatures . 2 Thermal residual stresses SiC)fabricated by chemical vapor infiltration( CVI)(TRS)are always generated in C/SiC composite during process have attracted considerable attentions as ad cooling from processing to room temperature due to an extensive mismatch of the coefficients of thermal This work was financially supported by The Centre for Foreign Talents Introduction and pansionCTEs)between fiber and matrix, which results cademic Exchange for Advanced Materials and Forming Technology Discipline and The in spontaneous cracking of the matrix. Using pyrolytic Research Fund of State Key Laboratory of Solidification Processing( Grant No. 44-QP. carbon(PyC) as an interphase between fiber and matrix 2009), Northwest Polytechnical University, Xi'an, China. can reduce the TRS of the C/SiC composite to some C 2010 The American Ceramic Society extent, which can be named as C/PyC/SiC compositeMicrostructure and Mechanical Properties of SiC and Carbon Hybrid Fiber Reinforced SiC Matrix Composite Shanhua Liu, Litong Zhang, Xiaowei Yin,* Laifei Cheng, and Yongsheng Liu National Key Laboratory of Thermostructure Composite Materials, Northwestern Polytechnical University, Xi’an, Shaanxi 710072, People’s Republic of China Silicon carbide (SiC) matrix composite reinforced by both SiC and carbon fibers ([SiC–C]/pyrolytic carbon [PyC]/SiC) was fabricated by chemical vapor infiltration for reducing matrix microcracks. Microstructure, mechanical properties, and oxidation resistance of the composite were compared with those of C/PyC/SiC and C/PyCHT/SiC composites in which PyC interphase was untreated and heat-treated at 18001C in argon, respectively. Compared with the C/PyC/SiC composite, (SiC– C)/PyC/SiC composite shows considerable improvements in flexural strength, fracture toughness, and oxidation resistance. The different mechanical behaviors of the three composites were analyzed based on the He and Hutchinson’s model. Introduction Silicon carbide (SiC) matrix composites reinforced with carbon fiber (C/SiC) and silicon carbide fiber (SiC/ SiC) fabricated by chemical vapor infiltration (CVI) process have attracted considerable attentions as ad￾vanced thermostructural materials for use in the aero￾space industry, owing to their low density, excellent thermal-shock resistance, and high mechanical proper￾ties at high temperatures.1,2 Thermal residual stresses (TRS) are always generated in C/SiC composite during cooling from processing to room temperature due to an extensive mismatch of the coefficients of thermal ex￾pansion (CTEs) between fiber and matrix, which results in spontaneous cracking of the matrix. Using pyrolytic carbon (PyC) as an interphase between fiber and matrix can reduce the TRS of the C/SiC composite to some extent, which can be named as C/PyC/SiC composite. Int. J. Appl. Ceram. Technol., 8 [2] 308–316 (2011) DOI:10.1111/j.1744-7402.2010.02588.x Ceramic Product Development and Commercialization r 2010 The American Ceramic Society This work was financially supported by The Centre for Foreign Talents Introduction and Academic Exchange for Advanced Materials and Forming Technology Discipline and The Research Fund of State Key Laboratory of Solidification Processing (Grant No. 44-QP- 2009), Northwest Polytechnical University, Xi’an, China. *yinxw@nwpu.edu.cn