DEVELOPMENT AND EVALUATION OF TRANSPARENT ALUMINUM OXIDE

Abstract

Polycrystalline alumina (Al2O3) possessing high total and in-line transmission in the visible range was prepared successfully by a combined high temperature hot forging and annealing operation. Transparency was found to be produced by a combination of several pore removal mechanisms active during deformation and primary recrystallization. A strong basal texture normal to the pressing direction was found for both deformation and recrystallization structures, and the high in-line transmission characteristics were thought to be due to a lowering of birefringent scattering because of this texture. Initial experiments were conducted to define the critical strain for recrystallization, and to date it is thought that this strain lies between 4 and 10 percent. Room and elevated temperature bend strengths of these materials were equivalent to opaque but dense pressure or pressureless sintered alumina having a comparable grain size.

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Document Details

Document Type
Technical Report
Publication Date
Jun 30, 1967
Accession Number
AD0661487

Entities

People

  • A. H. Heuer
  • David J. Sellers
  • Thomas Vasilos
  • William H. Rhodes

Tags

Communities of Interest

  • Air Platforms
  • Weapons Technologies

DTIC Thesaurus Topics

  • Aluminum Oxides
  • Ceramic Materials
  • Crystal Growth
  • Crystals
  • Diffraction
  • Forging
  • Grain Boundaries
  • Grain Growth
  • Grain Size
  • Heat Energy
  • Hot Pressing
  • Hot Working
  • Materials
  • Materials Engineering
  • Mechanical Properties
  • Optical Properties
  • Temperature Gradients

Fields of Study

  • Materials science

Readers

  • Optical Physics and Photonics.
  • Powder metallurgy of Titanium alloys.