Carbon-carbon composite

A problem in the production of carbon-carbon composites from carbon fiber reinforced thermoset composites through pyrolization is the cracking of the matrix due to internal stresses caused by the large shrinkage of the pyrolizing matrix and the simultaneous expansion of the fibers. Subsequent infiltration by carbon or silicon is limited to cracks open to the surface and will not reach the closed cracks in the interior. The present paper illustrates improvements as applied to the case of unidirectional fiber reinforcement capable of producing carbon-carbon composites without cracking the matrix and furthermore getting the matrix into amorphous state. As a result of this, at room temperature the composite shows the strength of HSLA steel together with reasonable pseudo ductility. At 1500 degrees C, the strength reaches the Values of 500-1000 N mm(-2). As the density is only 1.25-1.35 g cm(-3), the specific strength of the composite is very high. (C) 1997 Elsevier Science S.A.