Original Paper(Vol.61 No.5 pp.462-467)

Comparison of the Mechanical Property at High Temperatures of C/C Composites Fabricated from PAN- and Pitch-Based Carbon Fibers

Norio IWASHITA, Hiroshi YAMAUCHI and Shigeru SUZUKI

Abstract:Carbon fiber reinforced carbon composites (C/C composites) are fabricated from PAN- and pitch-based carbon fibers. The carbon matrix of the composites is prepared from phenol resin. In addition to this, the pitch matrix precursor is re-impregnated by HIP into the carbonized composite. Finally, the re-impregnated composites are graphitzed. The mechanical property of the composites is then evaluated using a 4-point bending test at ambient temperature, 2000 and 2200. The morphology of the C/C composites following the bending test at different temperatures is observed under OM and SEM. The bending strength of C/C composites at 2000 is ca. 1.5 times higher than that at ambient temperature, being independent of type of carbon fiber. The composite from PAN-based composites shows a lower modulus with the elevated test temperature from 2000 to 2200. On the other hand, the modulus of the composites from pitch-based carbon fiber shows almost no change at high temperatures. For the C/C Composite from pitch-based carbon fiber, it is observed that some buckling fractures of carbon fiber tows and plastic deformation of the carbon fibers is observed after the bending test above 2000. However, such fractures and deformation are rarely almost observed in the composite from PAN-based carbon fiber.

Key Words:C/C, Carbon Fiber, High temperature mechanical property, Bending test, Fractural morphology