GENERAL RESEARCH: MECHANICAL BEHAVIOR OF SAPPHIRE

Abstract

The present state of our knowledge on the mechanical behavior of sapphire is reviewed: Sapphire deforms plastically at temperatures above 900 C, the most common mode of deformation being slip on the basal plan in the <1120> direction. However, under certain conditions, slip may occur on prism planes or twinning may occur. A yield point is often observed. This appears to be related to the multiplication of dislocations by a mechaninism which is controlled by the motion of dislocations through the lattice, rather than by the tearing of dislocations from an impurity (or defect) atmosphere. The dynamics of yielding and flow is similar and can be expressed by either of two thermally activated equations. In one, the effect of stress is principally on the pre- exponential frequency factor; in the other, its effect is principally on the activation energy.

Open PDF

Document Details

Document Type
Technical Report
Publication Date
Mar 23, 1964
Accession Number
AD0435976

Entities

People

  • H. Conrad

Organizations

  • The Aerospace Corporation

Tags

Communities of Interest

  • Air Platforms

DTIC Thesaurus Topics

  • Creep
  • Crystal Structure
  • Dynamics
  • Energy
  • Equations
  • Heat Of Activation
  • High Temperature
  • Low Temperature
  • Materials
  • Materials Science
  • Plastic Flow
  • Sapphire
  • Strain Rate
  • Stress Strain Relations
  • Stresses
  • Tensile Stress
  • Yield Strength

Readers

  • Materials Science and Engineering.