Microstructure Studies of Polycrystalline Refractory Oxides

Abstract

The program was divided into three tasks within the general topic of microstructure effects on the properties of polycrystalline oxides. The press forging process was advanced to the point where a three-inch Al2O3 hemisphere of prescribed dimensions could be forged. The product had high transmissivity and a strong crystallographic texture. Initial experiments on press forging Si3N4 are reported. Three grades of powder used in the fabrication of hot pressed 99. 9% Al2O3 were found to contain particulate impurities which lead to inclusions and/or flaws in the product. Fracture origins were correlated with such flaws or other flawed features of structure in over 70% of the specimens tested. A study of gas/solid interactions in Al2O3 showed that CO was the major species evolved from material hot pressed in graphite.

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Document Details

Document Type
Technical Report
Publication Date
Apr 28, 1973
Accession Number
AD0760353

Entities

People

  • Philip L. Berneburg
  • Rowland M. Cannon
  • Warren C. Steele
  • William H. Rhodes

Tags

Communities of Interest

  • Advanced Electronics
  • Energy and Power Technologies

DTIC Thesaurus Topics

  • Absorption Coefficients
  • Aluminum Oxides
  • Chemical Reactions
  • Chemical Synthesis
  • Chemistry
  • Crystal Structure
  • Diffraction
  • Fabrication
  • Grain Growth
  • Grain Size
  • High Temperature
  • Materials
  • Materials Engineering
  • Measurement
  • Mechanical Properties
  • Mechanics
  • Spectra

Fields of Study

  • Materials science

Readers

  • Combustion science or combustion engineering.
  • Materials Science (Mechanical Engineering).
  • Powder metallurgy of Titanium alloys.