Abstract
Carbon fiber composites have gained attention as a structural material because of their high strength-to-weight ratio, and understanding the effect of defects on reactivity and mechanical properties is important for the longevity and safety of the composite. Although it is known that strain causes the underlying graphitic vibrational modes to redshift, it is not clear how strain may alter reactivity and defect-induced vibrational changes. To investigate the strain-induced phonon changes of defective carbon fiber composites, density functional theory calculations of graphite are used, including intercalated hydrogen and fluorine defects. By comparing changes in the bond lengths, formation energies, and phonon density of states for uniaxially and biaxially strained graphite, strain was found to generally make defect formation more favorable and the specific behavior changes are dependent on the strain direction and defect identity. Specifically, intercalated fluorine phonons are more sensitive to strain than hydrogen intercalation phonons, and strain applied along the zigzag direction alters the calculated properties more than strain along the armchair direction. These results highlight the importance of understanding the microstructural effect of deviations from the ideal material because small changes in strain or defect type can significantly alter the behavior of the carbon fiber composite core.
| Original language | English |
|---|---|
| Pages (from-to) | 16662-16671 |
| Number of pages | 10 |
| Journal | Journal of Physical Chemistry C |
| Volume | 128 |
| Issue number | 39 |
| DOIs | |
| State | Published - Oct 3 2024 |
Funding
This work was supported by the National Nuclear Security Administration. This research used resources of the Oak Ridge Leadership Computing Facility, which is a US Department of Energy Office of Science User Facility supported under Contract DE-AC05-00OR22725. The authors would like to thank the Real-space Multigrid developers for their assistance with the code and access to their Real-space Multigrid-Phonopy interface. 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 ). Acknowledgments This work was supported by the National Nuclear Security Administration. This research used resources of the Oak Ridge Leadership Computing Facility, which is a US Department of Energy Office of Science User Facility supported under Contract DE-AC05-00OR22725. The authors would like to thank the Real-space Multigrid developers for their assistance with the code and access to their Real-space Multigrid–Phonopy interface.