Graphite mechanical properties

The water hberated during the cure has no apparent effect on the composite properties. Glass-filled composites prepared in this manner retain mechanical properties at elevated temperatures as well as solvent and flammabiUty resistance (88). PhenoHc-graphite-fiber composites that exhibit superior mechanical properties have also been prepared by this process. 

Fig. 1. With-grain mechanical properties of artificial graphite (1). To convert MPa to psi, multiply by 145.

Mechanical Properties. The hexagonal symmetry of a graphite crystal causes the elastic properties to be transversely isotropic ia the layer plane only five independent constants are necessary to define the complete set. The self-consistent set of elastic constants given ia Table 2 has been measured ia air at room temperature for highly ordered pyrolytic graphite (20). With the exception of these values are expected to be representative of... 

All VGCF was graphitized prior to composite consolidation. Composites were molded in steel molds lined with fiberglass reinforced, non-porous Teflon release sheets. The finished composite panels were trimmed of resin flash and weighed to determine the fiber fraction. Thermal conductivity and thermal expansion measurements of the various polymer matrix composites are given in Table 6. Table 7 gives results from mechanical property measurements. 

As discussed earlier, the first wall materials in next generation machines will receive from 0.005 to 30 displacements per atom. At the lower end of this range (<0.01 dpa) there are essentially no mechanical property changes expected in graphite materials. However, even at these low doses thermal conductivity and stored energy are of concern. For displacement levels >0.01 dpa other property... 

Table 4. Physical and mechanical properties of some common nuclear graphites[l 1-19]...

S. Sato, K. Hirakawa, A. Kurumada, S. Kimura and E. Yasuda, Degradation of Fracture Mechanics Properties of Reactor Graphite Due to Bum-off, Nuclear Engineering and Design, Vol 118, 1990, pp 227 241... 

As an illustration of the results of the measurements just described, the mechanical properties for four unidirectionally reinforced composite materials, glass-epoxy, boron-epoxy, graphite-epoxy, and Kevlar 49 -... 

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