Creep of Carbon Yarns and Composites at High Temperatures.

Abstract

Creep was measured in unidirectional carbon-carbon composites (P55, HM3000, and WCA fibers with A240 and 15V pitch matrices) in tension (2-10 ksi) in the high-temperature range between 2000 and 3000 deg C. The composites were analyzed by optical and scanning electron microscopy to identify creep-elongation-induced changes in microstructure and mechanical properties. Such changes include matrix microcracking, fiber-matrix debonding, and filament necking. Rate mechanisms were also derived from the measured creep rates. The activation energies for the composites range from 50 to 130 kcal/mole. These values are smaller than activation energies for bulk graphites and indicate low-energy deformation mechanisms. Elastic modulus of the samples was measured before and after creep occurred. The observed increases or decreases are related to specific microstructural changes.

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Document Details

Document Type
Technical Report
Publication Date
Sep 30, 1988
Accession Number
ADA310443

Entities

People

  • L. A. Feldman

Organizations

  • The Aerospace Corporation

Tags

Communities of Interest

  • Advanced Electronics
  • Air Platforms
  • Sensors
  • Space

DTIC Thesaurus Topics

  • Carbon Carbon Composites
  • Carbon Fibers
  • Chemical Kinetics
  • Composite Materials
  • Electron Microscopy
  • Graphitic Materials
  • High Temperature
  • Material Degradation Processes
  • Materials
  • Materials Laboratories
  • Materials Processing
  • Materials Science
  • Mechanical Properties
  • Mechanical Working
  • Mechanics
  • Modulus Of Elasticity
  • Physics Laboratories

Fields of Study

  • Materials science

Readers

  • Materials Science (Mechanical Engineering).
  • Materials Science and Engineering.
  • Reinforced Composite Materials

Technology Areas

  • Microelectronics