THE TENSILE STRENGTH OF MAGNESIUM OXIDE
Abstract
Fully dense magnesium oxide bi-crystals and tricrystals were chemically polished very carefully to remove all th (Contract Nonr-245600, Proj. NR-032-451) Unclassified report DESCRIPTORS: *Crystals, *Magnesium compounds, *Oxides, Deformation, Plastic flow, Stresses, Surfaces, Impurities, Surface properties, Porosity, Fracture (Mechanics), Mechanical properties, Ceramic materials, Tensile properties. Identifiers: Disloca ions. Fully dense magnesium oxide bi-crystals and tricrystals were chemically polished very carefully to remove all the fresh slip dislocation sources normally present in the surface and then tested in tension. With this surface condition bi-crys als deform elasticall up to extremely high stresses ( > 110,000 psi) before separating from the tensile grips. Such a high strength is rarely achieved in practice because of two limiting factors, first, slip in the individual grains and second, residual porosity. When slip occurs, cracks are nucleated at the grain oundary due to dislocation pile up Fracture then occurs without ductility at the low tensile stress required to initiate slip (8,000 psi). In conventional polycrystalline material, prepared by sintering or hot pressing, there is inevitably some residual porosity at the grain boundaries. The intrinsic inished to remove surface dislocation sources. The bi-crystals deformed elastically up to 110,000 psi before eparating from tensile grips.
Document Details
- Document Type
- Technical Report
- Publication Date
- Jun 01, 1962
- Accession Number
- AD0278209
Entities
People
- C.h. Li
- R.j. Stokes
Organizations
- Honeywell International, Inc.