DISLOCATION DRAG MECHANISMS AND THEIR EFFECTS ON DISLOCATION VELOCITIES.
Abstract
Evidence is presented that dislocations move with nearly the shear speed of sound in the twinning process in tin and zinc. Such dislocations require a high shearing stress to start but progress through the body with a shearing stress in the order of 10 to the -4th power mu where mu is the shearing modulus. With the drag coefficient of zinc, which has been measured to be 7 x 10 to the -4th power dyne sec/cm sq at low velocities, this would be impossible unless the drag decreases at high velocities. It is shown that phonon and electron drag coefficients proposed by the writer have this property since at high velocities there is not time to interchange the thermal energy with the phonons and the drag coefficient becomes very small. (Author)
Document Details
- Document Type
- Technical Report
- Publication Date
- Feb 01, 1968
- Accession Number
- AD0667736
Entities
People
- W. P. Mason
Organizations
- Columbia University