INVESTIGATION OF THE RELATIONSHIP OF TWINNING TO BRITTLE FRACTURE OF REFRACTORY METALS

Abstract

The first year's work on this program is reported. It is concluded that there is good evidence for brittle fracture induced by mechanical twinning in single crystals and polycrystalline Mo-C with grain sizes larger than 0.40 mm. However there is no evidence for such failures in Mo-C of grain size smaller than 0.25 mm, or in high-purity Cb. The effect of recrystallization texture on twinning is demonstrated, and the orientation dependence of twinning in Cb crystals is reported; a most unusual plastic instability is described in crystals of one orientation. It is shown that twinning in Mo-35Re occurs in bursts, which form in less than 2 mu sec; nucleation of twins occurs only at small strains but lateral growth takes place up to at least 12% strain.

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Document Details

Document Type
Technical Report
Publication Date
Apr 01, 1963
Accession Number
AD0406245

Entities

People

  • A. Gilbert
  • C. N. Reid
  • G. T. Hahn

Organizations

  • Battelle Memorial Institute

Tags

Communities of Interest

  • Advanced Electronics
  • Air Platforms
  • Weapons Technologies

DTIC Thesaurus Topics

  • Air Force
  • Crystal Structure
  • Crystallography
  • Electron Microscopy
  • Grain Size
  • Materials
  • Materials Engineering
  • Materials Laboratories
  • Materials Science
  • Mechanical Properties
  • Mechanical Working
  • Metallurgy
  • Physics Laboratories
  • Stress Concentration
  • Stress Strain Relations
  • Stress Waves
  • Stresses

Readers

  • Materials Science and Engineering.
  • Mathematics or Statistics