Dissemination of IT for the Promotion of Materials Science (DoITPoMS)

DoITPoMS Micrograph Library Full Record for Micrograph 618

Full Record for Micrograph 618

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Micrograph no
Brief description
Fracture surface of a carbon fibre composite
alignment, carbon, carbon fibres Link to MATTER Glossary entry for carbon fibres, CFC, composite material Link to MATTER Glossary entry for composite material, epoxy Link to MATTER Glossary entry for epoxy, fibre Link to MATTER Glossary entry for fibre, fracture Link to MATTER Glossary entry for fracture, neutral axis Link to MATTER Glossary entry for neutral axis, polymer Link to MATTER Glossary entry for polymer, polymer composite, pull-out Link to MATTER Glossary entry for pull-out, reinforcement Link to MATTER Glossary entry for reinforcement, tensile
Composite, Fracture, Polymer, Polymer composite
Carbon fibre, epoxy resin matrix
Standard codes
Carbon fibres are produced by oxidising polyacrylonitrile in air at 230 deg C whilst applying tension, and then carbonising the product in nitrogen at 1000 deg C
A crude carbon fibre composite was made by laying out 40 tows of fibre, painting them with epoxy resin, compressing them in a mould, and curing them for five hours at 100-190 degrees C
Carbon fibre composites are used as a structural material in the aerospace and automotive industries, as well as in certain high-performance sporting equipment. They present exceptional stiffness and can be structurally optimised for particular load-bearing applications.
Sample preparation
The bar has been bent to failure in a three-point bending rig.
Scanning electron microscopy (SEM)
Length bar
600 μm
Further information
The neutral axis is clearly visible, up the centre of the image, with a region of ragged fibres indicating tensile failure to the left, and a smother, apparently crushed surface to the right where the beam was in compression. The holes and proud fibres in the tensile region are indicative of fibre pull-out which is a toughening mechanism in fibre composites.
J A Curran
Department of Materials Science and Metallurgy, University of Cambridge
Licence for re-use
Attribution-NonCommercial-ShareAlike 4.0 International
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