Study on the mechanical properties of C/C composites reinforced by different types of carbon fibers

With the aim of selecting suitable carbon fibers as reinforcement material for carbon/carbon composites, needled carbon fiber felt preforms are fabricated by T300 carbon fibers and TZ300 carbon fibers as raw material respectively. The industrial CT results of prepared deposited carbon/carbon (C/C) composites show that the porosity of the composites fabricated by T300 is higher than that of TZ300. The mechanical properties of C/C composites after deposition and heat treatment are comparatively investigated. The results show that the difference between two deposited composites is small, while the difference at high temperature is large. After 2100°C and 2450°C heat treatment, the mechanical properties of T300-C/C composites show a gradual decline, while the TZ300-C/C composites decrease sharply, indicating that the high-temperature properties of TZ300 carbon fiber is inferior to T300 carbon fiber. The fracture mechanisms of two composites are investigated through microscopic fracture observation. T300 carbon fibers are still attached to the pyrolysis carbon layer while TZ300 fibers are completely stripped from the fracture surface. The interfacial bonding between T300 and pyrolytic carbon is higher than that of TZ300.