Microplasticity, Tensile Failure, and Indentation Damage in Unflawed Polycrystalline Alumina.

Abstract

Scanning electron microscopy and acoustic emission has been used to study microfracture events occurring prior to tensile failure of unflawed Al2O3 tested at 23 and 410 C. A strengthening effect at the latter temperature is shown to be caused by multiple twinning, and enhanced twinning in general. Twinning is found to be responsible for crack initiation at room temperature. In other experiments, SEM was used to observe microfracture events in Al2O3 caused by sharp indenters. It was found that lateral crack formation was nucleated by mechanical twins located along the inner walls of the indents. The possible relationship of this process to erosion is discussed. (Author)

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Document Details

Document Type
Technical Report
Publication Date
Apr 06, 1977
Accession Number
ADA038426

Entities

People

  • James Lankford Jr.

Organizations

  • Southwest Research Institute

Tags

Communities of Interest

  • Air Platforms

DTIC Thesaurus Topics

  • Abstracts
  • Acoustic Emissions
  • Aluminum Oxides
  • Compression
  • Cracks
  • Electron Microscopy
  • Emission
  • Failure Mode And Effect Analysis
  • Materials
  • Mechanics
  • Microscopy
  • Polycrystals
  • Scanning Electron Microscopy
  • Strain Rate
  • Stress Waves
  • Stresses
  • Tensile Strength

Fields of Study

  • Materials science

Readers

  • Materials Science (Mechanical Engineering).

Technology Areas

  • Microelectronics