Abstract
Carbon fibers (CF) with radial and random microstructures are produced. These fibers are subjected to identical treatment before being mechanically tested and analyzed with Weibull analysis, with the results revealing a statistically significant difference in tensile strengths of 2.23 GPa for random CF and 1.69 GPa for radial CF. Raman mapping probed the crystalline structure perpendicular to the fiber axis and found a uniform structure, while wide-angle X-ray diffraction showed a significant difference of 7.5 Å in the crystallites’ basal lengths parallel to the fiber. Small-angle X-ray scattering is completed parallel to the fiber for the first time. A cross-section Guinier plot of the 1D azimuthal integration is generated assuming symmetric scattering, and the parallel scatterers are found to have a similar length scale to the crystallite's length, validating the testing method. Finally, transmission electron microscopy is completed on the longitudinal cross-section of each fiber. The radial carbon fiber is found to have a core–shell structure, as evidenced further by fast Fourier transform images. Through all studies, it is shown that the structure developed during mesophase pitch spinning altered the microstructure, thus impacting the mechanical properties, confirming a direct relationship between processing, structure, and properties.
| Original language | English |
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| Journal | Advanced Engineering Materials |
| DOIs | |
| State | Accepted/In press - 2025 |
Funding
This study was made possible through support from the U.S. Department of Energy, Hydrogen and Fuel Cell Technologies Office, Award Number DE‐EE0009239. The authors would like to thank the Nanoscale Materials Characterization Facility at the University of Virginia for providing access to the SEM, TEM, FIB, and WAXD machines. Confocal micro Raman spectroscopy was conducted as part of a user project at the Center for Nanophase Materials Sciences (CNMS), which is a US Department of Energy, Office of Science User Facility at Oak Ridge National Laboratory. The authors thank the University of Virginia Chemistry Department for access to the single‐crystal XRD machines funded by the NSF‐MRI program, grant award CHE‐2018870. The authors also thank Dr. Diane Dickie for assistance with the operation of the instruments and numerous helpful discussions. This manuscript has been authored by UT‐Battelle, LLC, under contract DE‐AC05‐00OR22725 with the US Department of Energy (DOE). The US government retains and the publisher, by accepting the article for publication, acknowledges that the US government retains a nonexclusive, paid‐up, irrevocable, worldwide license to publish or reproduce the published form of this manuscript, or allow others to do so, for US government purposes. DOE will provide public access to these results of federally sponsored research in accordance with the DOE Public Access Plan (http://energy.gov/downloads/doe‐public‐access‐plan).
Keywords
- carbon fiber
- microstructure
- structure–property–relationship