Effect of Uniaxial Stress on the Raman Spectra of Graphite Fibers.
Rept. for 1 Sep 86-31 Aug 87,
MASSACHUSETTS INST OF TECH CAMBRIDGE
Pagination or Media Count:
Measurements of the effect of uniaxial stress on the frequency of the zone center optical phonons in heat-treated benzene-derived graphite fibers have been performed using first-order Raman scattering. Application of uniaxial stress along the fiber axis was found to cause polarization-dependent splittings and shifts of the Raman peaks of the zone center doubly degenerate optical phonons. From these observed splittings and shifts, experimental values for the phenomenological coefficients which describe the changes in the elastic constant of these phonons with strain were determined. It is concluded that Raman spectroscopy can be used to characterize the local stress or strain conditions of graphite fibers nondestructively. Keywords Effect of uniaxial stress, Raman spectra of carbon fibers, Raman microprobe spectroscopy, Single carbon fibers.
- Refractory Fibers