STUDY OF THE PROPERTY AND PROCESSING OF CERAMIC MATRIX COMPOSITES REINFORCED WITH 3D-BRAID WOVEN FABRICS

The processing of Ceramic Matrix Composites (CMC)reinforced with 3D-braid woven fabrics via polycarbosilane (PCS) pyrolysis was investigated. Also studied were the influences of different kinds of processing on the macro and micro properties of composites. Several ways were proposed.which can improve the processing and enhance the properties of composites, The results indicate that the pyrolysis time is considerably reduced by infiltration-curing-pyrolysis of a PCS/DVB system,and the densification efficiency is significantly enhanced compared with PCS/Xylene solution infiltration. The 3D-braid C_f/SiC CMC specimens have a density of 1.65g/c³,a flexural strength of 326MPa and a fracture toughness of 13.72MPam^1/2 after infiltration-curing-pyrolysis cycle. of 7 times for the PCS/DVB system,and have a density of 1.54g/c³,a flexural strength of 243MPa and a fracture toughness of 8.19MPam^1/2 after infiltration-pyrolysis for the PCS/Xylene system. The fracture surfaces of the flexural specimens were also investigated by SEM including fibers pull-out,fibers fracture,etc.