Compressive Strength of Polycrystalline Alumina.
Abstract
The compressive strength of polycrystalline alumina at 23C is found to be strain rate and temperature sensitive, but insensitive to environment. Scanning electron microscopy of specimens loaded to near failure indicates the basis of the thermally-activated process which controls failure to be localized plasticity in the form of twinning and, possibly, slip. The interaction of these deformation bands with grain boundaries causes the initiation of microcracks. Higher stresses produce still more twin/slip nucleated microcracks, which finally coalesce at failure. Twinning occurs at stresses below 50% of the failure strength and may play a role in crack nucleation during indentation and impact loading. It is suggested that twinning also may be related to the tensile failure of alumina.
Document Details
- Document Type
- Technical Report
- Publication Date
- Apr 30, 1976
- Accession Number
- ADA024145
Entities
People
- James Lankford Jr.
Organizations
- Southwest Research Institute