The positive role of mesophase-pitch-based carbon fibers in enhancing thermal response behavior in Carbon/Carbon composites

The high-thermal-conductive Carbon/Carbon (HTC-C/C) composites using mesophase-pitch-based carbon fibers (CFMP) as heat conduction carriers are promising thermal management materials in high-tech fields. The composites undergo a complex dynamic temperature variation in practical application and their thermal response behavior and the enhancing effect of CFMP are not clear. The one-dimensional, two-dimensional and three-dimensional HTC-C/C composites were prepared with thermal conductivity of 528 W·m−1·K−1, 429 W·m−1·K−1 and 437 W·m−1·K−1 in the CFMP direction, respectively, and the thermal response behaviors were investigated by infrared thermal imager. The results reveal that the graphitized CFMP with azimuth angle 7.69°, graphitization degree 75.49% and thermal conductivity 700 W·m−1·K−1 can transfer heat efficiently in the composite. The temperature variation and distribution of composites are all determined by the CFMP arrangement and have a good corresponding relationship with the size and shape of pore defects. In comparison with one-dimensional composite, the two-dimensional and three-dimensional composites exhibit pronounced “striped” and “grid-like” temperature distribution, respectively.