Compressive Strength and Damage Mechanisms in Ceramic Materials. I. The Role of Subcritical Tensile Microfracture Processes in Compression Failure of Ceramics. II. Electron Channeling Study of Fracture in Alumina-Evidence for Crack Tip Plasticity.
Abstract
The compressive strength of SiC, Si3N4, and Al2O3 is investigated over wide ranges in temperature and loading rate. Several distinct damage regimes are identified, all based upon tensile microfracture processes. Two aspects of the work are of special interest. The first is the identification of a high strain rate regime in which material inertial effects are responsible for unusually rapid strengthening; the basis for the effect is increased difficulty in either crack nucleation or extension. Secondly, it is found that at low loading rates, subcritical tensile microcrack growth is responsible for a thermally activated strength dependence. Selected area electron channeling experiments lead to the conclusion that the thermal activation process may involve crack tip plasticity. (Author)
Document Details
- Document Type
- Technical Report
- Publication Date
- Sep 01, 1981
- Accession Number
- ADA107617
Entities
People
- David L. Davidson
- James Lankford
Organizations
- Southwest Research Institute