Effect of heat treatment on mechanical properties of C/C composites with C SiC TaC C multi-interlayers

C-SiC-TaC-C multi-interlayers were introduced in the carbon fiber/carbon matrix interface in quasi 3D needled carbon felt by chemical vapor infiltration, the modified C/C porous performs were densified by impregnation-carbonization processes to obtain C/C composites with C-SiC-TaC-C multi-interlayers. The microstructure and mechanical properties were studied after heat treatment (HTT) at different temperatures of 1400～2500℃. The results show that the SiC-TaC interlayers have a tubular structure before HTT; while the average flexural strength of the as-prepared composites is 241.6 MPa with a brittle fracture. After HTT at 1400～1800℃, TaC interlayer is damaged to granular structure; As a result, the flexural strength of the composites declines to 238.9～226.1 MPa also with a brittle fracture, but an increasing of fracture displacement from 0.7 mm to 1.0 mm. After HTT at 2000～2500℃, both SiC and TaC interlayer are damaged. The flexural strength sharply declines to 158.7～131.8 MPa with an obvious change of fracture behavior from brittleness to pseudo-ductility.