Effect of Active Al Fillers on Properties of PIP-derived SiC_f/SiC Composites

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 A1 and inert SiC filler were introduced to enhance the infiltration efficiency.The effects of A1 filler addition and thickness of PyC as interphase on mechanical properties of the composites were characterized.The mechanical properties of the composite with active A1 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.