Research and Development on Advanced Graphite Materials: Volume II - Applications of Anisotropic Elastic Continuum Theory to Dislocations in Graphite

Item

Title
Research and Development on Advanced Graphite Materials: Volume II - Applications of Anisotropic Elastic Continuum Theory to Dislocations in Graphite
Date
1962
Index Abstract
Contrails and DTIC truncated
Photo Quality
Not Needed
Report Number
WADD TR 61-72 Volume II
Corporate Author
National Carbon Company
Laboratory
Directorate of Materials and Processes
Extent
54
Identifier
AD0286090
AD0286090
Access Rights
OTS
Distribution Classification
1
Contract
AF 33(616)-6915
DoD Project
7350
DoD Task
735002
DTIC Record Exists
No
Distribution Change Authority Correspondence
None
Abstract
Eshelby, Read, and Shockley's theory of dislocations in an anisotropic elastic continuum has been used to derive formulas not involving complex numbers for the stress components of straight dislocations in certain symmetry directions. From these the dependence of stacking fault energy γF on the orientation of the Burgers vector and on the width of extended dislocations and triple partial ribbons and the dependence of γF on the radius of curvature of extended nodes were calculated. The results are rigorous for hexagonal crystals and approximate for general directions in (111) planes of FCC crystals. The theory is applied to graphite and lose-packed metals. All three methods of determining γF for graphite yield results which are compatible with the value 0.6 ± 0.2 erg/cm2. The rough estimate of error is based on uncertainties in the elastic constants and differences in experimental results. The dependence of width on depth from the stress-free surface has been calculated for an arbitrarily oriented dislocation lying parallel to the surface of a semi-infinite isotropic body and 30° extended dislocation and a symmetrical, screw triple partial ribbon in certain symmetry directions in an anisotropic plate. A procedure for correcting the widths observed in electron microscopy of thin films is given.
Report Availability
Full text available
Date Issued
1962-07
Subject
Graphite
Stresses
Bibliographies
Crystals
Deformation
Elastic Properties
Mathematical Analysis
Surfaces
Theory
Publisher
Wright-Patterson Air Force Base, OH : Directorate of Materials and Processes, Aeronautical Systems Division, Air Force Systems Command
Distribution Conflict
No
Provenance
Lockheed Martin Missiles & Fire Control
Type
report
Format
1 online resource
Creator
Spence, G. B.