Accession Number : ADA193211

Title :   Effect of the Matrix on the Creep-Behavior of Carbon-Carbon Composite.

Descriptive Note : Technical rept.,

Corporate Author : CALIFORNIA UNIV LOS ANGELES DEPT OF MATERIALS SCIENCE AND ENGINEERING

Personal Author(s) : Sines, George H ; Yang, Zheng ; Vickers, Brian D

PDF Url : ADA193211

Report Date : Nov 1987

Pagination or Media Count : 39

Abstract : Creep specimens and experiments were designed to determine the properties of carbon carbon composites at high temperatures (over 2310 C) and at high stress levels (over 770 MPa). During the course of these experiments it was observed that the carbon matrix greatly increases the creep resistance of carbon fibers in properly impregnated, uniaxial composites. Results show how a composite specimen creeped 3.6% after 5.9 hrs. of testing while a matrix-free specimen, at the same test conditions, ruptured with 138% strain after only 0.39 hrs. This improvement is attributed to the alignment of the mesophase layers of the carbon matrix, which distribute tensile loads more evenly amongst the filaments and which may also alter the filaments' stress state by restricting transverse strains. Also of interest was the large primary creep response associated with the composite specimens at these high stress and temperature levels. Because it was such a large percentage of the entire response, this initial, transient creep should become the main design parameter of any attempt to relax bundle stresses in the fabrication of carbon carbon billets.

Descriptors :   *CARBON CARBON COMPOSITES, *CARBON FIBERS, *CREEP STRENGTH, BILLETS, CREEP, FILAMENTS, MATRIX MATERIALS, RATES, BONDING, PHASE STUDIES

Subject Categories : Laminates and Composite Materials

Distribution Statement : APPROVED FOR PUBLIC RELEASE