Dislocation kinetics
A series of investigations have been underway to determine in a more rigorous manner the thermally activated motion of a single dislocation and a group of dislocations through a random array of short range barriers (s.r.b.). This was accomplished by developing computer models to stimulate the motion of dislocations. These models require the use of far fewer assumptions in comparison with analytical solutions. The parameters which were investigated were: the strength and density of s.r.b., criterion for thermal fluctuation over the s.r.b., size and shape of slip plane, the magnitude of the lattice resistance, i.e., the Peierl's stress, and in the case of a group of dislocations the criterion for the dislocation source operation, and the differences between single and group motion on a one and two dimensional slip plane. The results obtained from the investigations of the motion of single dislocation indicate that if the s.r.b. is weak, the numerical results are in agreement with analytical results predicted by Friedel. If the Peierl's stress is non-zero then the s.r.b. can produce a reduction in the stress required to maintain a given dislocation velocity. If a multiple group of dislocations are in motion on the slip plane it is possible to have two types of pile-ups. If the dislocations remove s.r.b., as in channeling of irradiated metals, then a normal pile-up occurs. However, if the s.r.b. are not removed, an inverted pile occurs.
- Research Organization:
- Univ. of Maryland, College Park
- OSTI ID:
- 7138121
- Journal Information:
- Nucl. Metall.; (United States), Journal Name: Nucl. Metall.; (United States) Vol. 20; ISSN NMAIA
- Country of Publication:
- United States
- Language:
- English
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