FRACTURE AND TWINNING IN SAPPHIRE (ALPHA AL2O3 CRYSTALS)

Abstract

The fracture behavior of 60 degree oriented sapphire crystals was investigated for both tension and compression. Plastic flow on the basal plane was found to be a factor in reducing the tensile stress required to produce fracture in the temperature range 1100 to 1500 C. Mechanical twins, both (0001) and (0111) types, were produced by compression in the temperature range 1100 to 1300 C. Cracks propagated more readily along the twin boundaries than in the nontwinned crystal.

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Document Details

Document Type
Technical Report
Publication Date
Mar 15, 1963
Accession Number
AD0404556

Entities

People

  • E. Stofel
  • H. Conrad

Organizations

  • The Aerospace Corporation

Tags

Communities of Interest

  • Air Platforms

DTIC Thesaurus Topics

  • Air Force
  • Chemical Compounds
  • Compression
  • Crack Propagation
  • Crack Tips
  • Flow
  • Materials
  • Materials Science
  • Orientation (Direction)
  • Plastic Flow
  • Sapphire
  • Strain Rate
  • Stress Concentration
  • Stress Waves
  • Stresses
  • Tensile Stress
  • X Rays

Readers

  • Materials Science (Mechanical Engineering).
  • Materials Science and Engineering.