Direct Observations of Fracture and the Damage Mechanics of Ceramics

Abstract

An experimental study of the R-curve behaviour of an Alumina ceramic by in-situ SEM has yielded detailed information on the extent of the R-curve in this material as well as on the actual physical mechanisms responsible for the toughness increase. These have been identified as both ligamentary bridging due to crack bifurcation and bridging by wedged grains between the crack faces which dissipates energy by friction. Simple modelling calculations show that these mechanisms can account for the 75% increase in toughness observed using the double torsion technique. Further, the feasibility of Plaster of paris as a model ceramic material for damage mechanics investigations has been examined and extensive mechanical property characterization has been carried out. Keywords: Ceramics; Alumina; Fracture; R-curve; Scanning electron microscopy; In-situ observations; Damage mechanics; Uniaxial and Hydrostatic compression; Plaster of paris.

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Document Details

Document Type
Technical Report
Publication Date
Oct 31, 1988
Accession Number
ADA204262

Entities

People

  • G. Vekinis
  • M. F. Ashby
  • P. W. Beaumont

Organizations

  • University of Cambridge

Tags

Communities of Interest

  • Air Platforms
  • Energy and Power Technologies
  • Weapons Technologies

DTIC Thesaurus Topics

  • Air Force
  • Ceramic Materials
  • Civil Engineering
  • Crystal Structure
  • Elastic Properties
  • Electron Microscopes
  • Failure Mode And Effect Analysis
  • Fracture (Mechanics)
  • Geometry
  • Grain Size
  • Materials Science
  • Measurement
  • Mechanical Properties
  • Mechanics
  • Micromechanics
  • Modulus Of Elasticity
  • Plastic Properties

Fields of Study

  • Engineering
  • Materials science

Readers

  • Materials Science (Mechanical Engineering).
  • Mechanical Engineering/Mechanics of Materials.

Technology Areas

  • Microelectronics