|
Abstract:
The in situ stress graphitization behavior of hard carbons in unidirectionally aligned carbon-carbon (C-C) composites was studied for three carbon fibers (PAN-based T-50, pitch-based PX7, and rayon- based WCA) and two carbon precursor resins (phenol-formaldehyde (SC1008), and polyarylacetylene (PAA), a high char-yielding, low shrinkage resin). Graphitization was followed by measurements of density, transverse thermal expansion, d-spacing by X-ray diffraction (XRD), and by scanning electron microscopy (SEM). In conjunction with xenon-iron etching, the SEM technique was found to be particularly effective in identifying localized regions of graphitized matrix. Results reveal that the graphitization of the composite is significantly greater than graphitization of fiber or matrix alone to the same temperatures. SEM observations indicate that graphitization is confined to the matrix, usually as a sheath-like structure adjacent to the fiber and 1-3 microns thick. Such localized graphitization, usually termed stress graphitization, is believed to be the result of thermally induced tensile or compressive stresses acting at the fiber-matrix interface. Debonded regions, which are believed to either initiate at heat up or grow from pre-existing cracks in the resin-matrix composite, show less stress graphitization than well-bonded regions, presumably because the debond gaps impede stress buildup at the fiber-matrix interface.
| Description: |
Journal article |
| Pages: |
9 |
| Report Date: |
1991 |
| Contract Number: |
F0470188C0089 |
| Report Number: |
D317358 |
Report Unavailable |
| This title is unavailable from Storming Media. We do not know when it might be available, if at all. We list the report on our site for bibliographic completeness, to help our users know what other work has been performed in this field. Please note that as with all titles on this site, we do not have contact information for any of the authors. Nor can we give any suggestions on how one might obtain this report. |
|
|
|
|
|
Keywords relating to this report:
Email This Abstract
