Dynamic mechanical analysis of a two-dimensional carbon-carbon composite

Abstract

A two-dimensional carbon-carbon composite material consisting of stacked carbon cloths densified with a carbon matrix has been characterized with respect to its dynamic mechanical properties. Unprotected specimens and some protected against oxidizing conditions were investigated over the temperature range of subambient (−100°C) to 500°C. The reproducibility of the calculated storage modulus as well as the loss factor was within 5% at any one temperature over the entire temperature range. Results concerning protected and unprotected specimens were compared analytically and the difference of the relative plots above 400°C reflects the bad corrosion resistance of the unprotected samples under oxidizing conditions, where the carbon matrix material is more sensitive to oxidation than the fibre. The transition regions which appeared on the loss factor plots are strongly connected with the relevant secondary transition regions of the antioxidation protected material used. This technique, which has been demonstrated to be non-destructive for the sample analysed, proved that no differences exist in the dynamic mechanical properties of the specimens with respect to fibre orientation (warp or weft direction). Details of the experimental technique and assumptions made are also presented.