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Dislocation velocity and slip on the (1'21'2) (12'13) systems of zinc

Citation

Blish, Richard Clark (1967) Dislocation velocity and slip on the (1'21'2) (12'13) systems of zinc. Dissertation (Ph.D.), California Institute of Technology. http://resolver.caltech.edu/CaltechETD:etd-09172002-144540

Abstract

Slip bands on the {1212} <1213> systems of zinc were produced by stress pulses and were observed by etch pitting.. Edge and screw dislocation velocities as a function of stress and temperature (77° to 323°K) were deduced by measurement of the size of the slip bands. For the low temperature range of 77° to 110°K it is found that dislocation velocity is proportional to (stress) exp(-U/kT) where U = 0.182 ev. Screw dislocation velocity is found to be larger than edge dislocation velocity at a constant stress. It is suggested that a Peierls mechanism controls the dislocation velocity for the low temperature range. Above 110°K the slip bands start to become wider as cross glide takes precedence over the Peierls mechanism for the limitation of dislocation velocity. It is found that dislocation velocity decreases and the amount of cross glide increases with increasing temperature. It is suggested that the dislocations are retarded by an increasing number of dragging dipoles. The experimentally measured dislocation velocities are also related to the macroscopic measurements of the yield stress and the work hardening coefficient.

Item Type:Thesis (Dissertation (Ph.D.))
Subject Keywords:crossglide; dislocation; Peierls; stress; velocity; cross slip; etch pitting; X-ray topography; Bridgeman crystal growth; acid saw and polishing; stress pulse
Degree Grantor:California Institute of Technology
Division:Engineering and Applied Science
Major Option:Materials Science
Thesis Availability:Public (worldwide access)
Research Advisor(s):
  • Vreeland, Thad
Thesis Committee:
  • Vreeland, Thad (chair)
  • Wood, David Shotwell
  • Buffington, Francis Stephan
  • Housner, George W.
  • Duwez, Pol E.
Defense Date:25 May 1967
Author Email:richard.blish (AT) gmail.com
Record Number:CaltechETD:etd-09172002-144540
Persistent URL:http://resolver.caltech.edu/CaltechETD:etd-09172002-144540
Default Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:3575
Collection:CaltechTHESIS
Deposited By: Imported from ETD-db
Deposited On:18 Sep 2002
Last Modified:13 Feb 2014 23:37

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