Does Anyone Out There Know the Strength of Sapphire?

Abstract

Results are compared for several different sets of 4-point flexure strength measurements on sapphire as a function of crystal orientation and temperature. The only consistent trend is that strength drops rapidly with increasing temperature when the c-axis of the crystal is the principal axis of tension and compression. Using Grafoil between sapphire and the load fixture increases the apparent strength of specimens whose principal axis is c by a factor of 2-3, but has little effect on other crystallographic orientations. The rate of crack propagation on the m-plane of sapphire increases by 7 orders of magnitude between 20 and 600 deg C.

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Document Details

Document Type
Technical Report
Publication Date
May 01, 2002
Accession Number
ADA421203

Entities

People

  • Daniel G. Harris

Organizations

  • Naval Air Systems Command

Tags

Communities of Interest

  • Air Platforms

DTIC Thesaurus Topics

  • Ceramic Materials
  • Composite Materials
  • Crack Propagation
  • Cracks
  • Crystals
  • Data Sets
  • High Temperature
  • Materials
  • Mechanical Properties
  • Resistance
  • Sapphire
  • Shock Resistance
  • Silicon Carbide
  • Standards
  • Stress Intensity Factors
  • Stresses
  • Thermal Shock

Readers

  • Materials Science and Engineering.
  • Mechanical Engineering/Mechanics of Materials.