Journal of Materials Science

, Volume 21, Issue 6, pp 1853–1862 | Cite as

Fractography of unidirectional graphite-epoxy as a function of moisture, temperature and specimen quality

  • Linda L. Clements
Papers

Abstract

The tensile failure surfaces of (0°)8 T300/5208 graphite-epoxy specimens were examined using both optical and scanning electron microscopy. Fractography was used to determine how moisture content and temperature as well as specimen preparation technique, prepreg batch and cure condition affected the failure mode. A distinctive “low-energy” failure morphology was found in defective specimens and also in those whose edges were poorly prepared. This morphology was predominant in failures at elevated temperature or moisture content for specimens which had been made from one suspect batch of prepreg. This finding combined with unusual end-tab failures from such specimens indicated that this batch was indeed “defective”, but that such defective batches could in the future be identified by tests under hot, wet conditions. For specimens made from “good” prepreg, temperature or moisture appeared to decrease flaw sensitivity and thus increase strength, even though moisture also seemed to increase interfacial debonding between filament and matrix. When combined, moisture and temperature appeared to degrade performance by increasing interfacial debonding and making the epoxy matrix more prone to fracture.

Keywords

Polymer Electron Microscopy Scanning Electron Microscopy Epoxy Elevated Temperature 

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Copyright information

© Chapman and Hall Ltd. 1986

Authors and Affiliations

  • Linda L. Clements
    • 1
  1. 1.Materials Engineering DepartmentSan Jose State UniversitySan JoseUSA

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