Connecting mechanical properties to hydrogen defects in PAN-based carbon fibers

Z. E. Brubaker, S. B. Isbill, A. J. Miskowiec, W. S. Charlton, L. Daemen, and J. L. Niedziela

Phys. Rev. Materials 7, 093603 – Published 14 September 2023

Abstract

Atomic-level defects dictate the mechanical properties of carbon fibers and strong correlations have been established between the crystallite sizes and mechanical properties. We recently demonstrated similar correlations with hydrogen content, but reliably quantifying the hydrogen content is not possible using only inelastic neutron scattering experiments. Here, we present prompt-gamma activation analysis (PGAA) experiments collected on 20 commercially available carbon fibers to quantify the hydrogen content of carbon fibers and find correlations between fiber modulus and hydrogen content. We then evaluate the role of hydrogen defect type and connect the PGAA results to both newly acquired and recently reported inelastic neutron scattering experiments. We find that intercalated hydrogen defects are preferentially removed at carbonization temperatures required for high-modulus fibers, potentially giving rise to voids within the carbon fibers that undermine their tensile strength.

Received 5 June 2023
Accepted 22 August 2023

DOI:https://doi.org/10.1103/PhysRevMaterials.7.093603

Physics Subject Headings (PhySH)

Defects Lattice dynamics

Carbon-based materials

Neutron scattering

Condensed Matter, Materials & Applied Physics

Authors & Affiliations

Z. E. Brubaker ¹, S. B. Isbill¹, A. J. Miskowiec ¹, W. S. Charlton ², L. Daemen¹, and J. L. Niedziela ¹

¹Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, USA
²Department of Mechanical Engineering, University of Texas at Austin, Austin, Texas 78712, USA