ISSN:
1573-4803
Source:
Springer Online Journal Archives 1860-2000
Topics:
Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
Notes:
Abstract Type I PAN-based carbon fibres have been stressed to failure in glycerol; this enables the fracture ends to be preserved intact for subsequent examination, first by scanning electron microscopy, then, after embedding and sectioning, by transmission electron microscopy. Internal flaws which did not initiate failure was seen to have walls containing crystallites arranged mainly parallel to the fibre axis. Internal and surface flaws which did initiate failure showed evidence of large misoriented crystallites in the walls of the flaws. It is the presence of misoriented crystallites rather than the flaw itself which determines whether or not tensile failure will occur. Our observations are entirely consistent with the Reynolds-Sharp mechanism of tensile failure in which the concentration of shear energy in a misoriented crystallite is not relieved by cracks parallel to the layer planes but by cracks at right angles. It is possible to predict that, in the absence of gross flaws, breaking strains of 1 to 1.3% should be possible in Type I PANbased carbon fibres, and greater than 2% in Type II carbon fibres.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1007/BF00544159
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