OBSERVATIONS OF DISLOCATIONS IN CAWO4 BY TRANSMISSION ELECTRON MICROSCOPY.

Abstract

The distribution of dislocations in deformed calcium tungstate was studied by electron transmission microscopy. The photomicrographs confirmed earlier optical observations that (001) <100> is the slip system of this material between 500 - 900C. Screw dislocations, long edge dislocation dipoles, quadrupoles and tangles of dislocations were observed in foils prepared from specimens deformed at 500C. Specimens deformed at 700C showed similar features, except that many of the long dipoles had split into long strings of prismatic loops. At 900C the loops were more isolated and sometimes grew to a diameter exceeding the thickness of the foil. Many single dislocations could also be seen with nearly pure edge or screw orientation. Two models are proposed for quadrupole formation and their relative stability considered. Strain hardening is thought to be due to the interaction of dislocations with multipoles and prismatic circular loops. (Author)

Document Details

Document Type
Technical Report
Publication Date
Jul 01, 1965
Accession Number
AD0618212

Entities

People

  • A. Arbel
  • R. J. Stokes

Organizations

  • Honeywell International, Inc.

Tags

DTIC Thesaurus Topics

  • Diameters
  • Dislocations
  • Electron Microscopy
  • Electrons
  • Hardening
  • Materials
  • Microscopy
  • Observation
  • Optical Analysis
  • Orientation (Direction)
  • Strain Hardening
  • Thickness
  • Transmission Electron Microscopy
  • Tungstates

Fields of Study

  • Physics

Readers

  • Materials Science and Engineering.
  • Plasma Physics / Magnetohydrodynamics

Technology Areas

  • Microelectronics