High-Toughness Glass-Ceramics.

Abstract

Two different methods were used to prepare tough glass-ceramics containing ZrO2. One was to melt ZrO2-containing Li2O-Al2O3-SiO2 glasses and transform them by control led crystallization. The other was to sinter BaO-SiO2-Al2O3 glass powder together with ZrO2 powder. In both materials, some toughness improvement by the transformation of zirconia during fracture was observed. However, unexpectedly, the greater toughness improvement was realized when the zirconia particles in the glass-ceramics were transformed prior to the fracture by cooling to a lower temperature, e.g., liquid nitrogen temperature. This drastic increase of the fracture toughness was attributed to the deflection of the propagating crack by the large stress fields around the transformed (monoclinic) zirconia. The examination of the fracture surface demonstrated clearly that the crack deflection is taking place in the specimen with transformed zirconia. (MM)

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Document Details

Document Type
Technical Report
Publication Date
Aug 31, 1994
Accession Number
ADA290562

Entities

People

  • Minoru Tomozana

Organizations

  • Rensselaer Polytechnic Institute

Tags

Communities of Interest

  • Human Systems

DTIC Thesaurus Topics

  • Crack Propagation
  • Cracks
  • Deflection
  • Glass
  • Glass Transition Temperature
  • Heat Treatment
  • High Temperature
  • Materials
  • Materials Engineering
  • Mechanical Properties
  • Nitrogen
  • Particles
  • Residual Stress
  • Silicates
  • Stresses
  • Toughness
  • Transition Temperature

Fields of Study

  • Materials science

Readers

  • Materials Science (Mechanical Engineering).
  • Powder metallurgy of Titanium alloys.