DYNAMICAL BEHAVIOR OF DISLOCATIONS,

Abstract

Direct and indirect measurements of dislocation mobilities are reviewed. It is pointed out that no single functional relation between dislocation velocity and stress exists. Four limiting cases are classified schematically: (a) pure metals and salts (b) covalent crystals and impure others; each at low and high stress levels. For cases (a) and (b) at low stress levels linear viscosity is observed. It is pointed out that a previous treatment of the viscous drag by Mason neglects the dominant role of glide plane sliding and a new treatment is presented. For case (b) at high stress levels (low temperatures) flow is stress-activated and a model based on quantum-tunneling is presented and shown to compare favorably with experiments. The behavior of heterogeneous crystals is discussed. A model proposed by Copley and Kear that predicts dynamic anisotropy is reviewed. (Author)

Document Details

Document Type
Technical Report
Publication Date
Sep 01, 1967
Accession Number
AD0658874

Entities

People

  • John J. Gilman

Organizations

  • University of Illinois Urbana–Champaign

Tags

Communities of Interest

  • Air Platforms

DTIC Thesaurus Topics

  • Anisotropy
  • Dislocations
  • Dynamic Loads
  • Low Temperature
  • Materials
  • Measurement
  • Mobility
  • Physical Properties
  • Quantum Phenomena
  • Quantum Tunneling
  • Tunneling
  • Viscosity

Readers

  • Materials Science and Engineering.
  • Theoretical Analysis.

Technology Areas

  • Quantum Computing