Abstract: SiC_f/SiC composites were fabricated by a polymer infiltration and pyrolysis process using 2.5D SiC fiber preforms. In the first slurry infiltration process, active Al and inert SiC filler were introduced to enhance the infiltration efficiency. The effects of Al filler addition and thickness of PyC as interphase on mechanical properties of the composites were characterized. The mechanical properties of the composite with active Al as the filler are remarkably improved. The bending strength and proportional limit stress reach 441MPa and 380MPa, respectively. In the range of 200--500nm, the effect of PyC thickness on the bending strength is not noticeable. The elastic modulus of the composite slightly decreases with the increase of PyC thickness.

Key words: SiC_f/SiC composite, reactive filler, polymer infiltration and pyrolysis, mechanical properties