RECENT OBSERVATIONS ON THE MOTION OF SMALL ANGLE DISLOCATION BOUNDARIES
Abstract
Arrays of edge dislocations which produce low-angle boundaries in Zn single crystals can be made to move by the application of an appropriate shear stress at temperatures from -196 to 400 deg C. Continued motion at -196 C required the application of a steadily increasing stress. At room temperature the movement was discontinuous. At elevated temperature, motion was steady, and a thermally activated creep process seemed to predominate. The deformation of Zn in simple shear showed characteristics very similar to those of moving bounaries at the same temperatures. This implied that the propagation of dislocations rather than their generation may be factor which determines the yield strength of Zn crystals. During the motion of a boundary at elevated temperatures the boundary changed in character both with regard to angle and regularity. Small angle boundaries of like sign in proximity to one another coalesced during short-time annealing treatments at 400 deg C to form a single boundary. Curved boundaries tended to become planar and perpendicular to the slip direction as a result of such treatment. Boundaries of unlike sign were also made to join by means of stress at both high level and low temperatures is in accord with theoretical predictions that dislocations of opposite sign can be mutually destructive.
Document Details
- Document Type
- Technical Report
- Publication Date
- Aug 01, 1953
- Accession Number
- AD0018347
Entities
People
- Choh H. Li
- Douglas W. Bainbridge
- Earl R. Parker
- Eugene H. Edwards
- Jack Washburn
Organizations
- University of California, Berkeley