Impurity effects on the creep of polycrystalline magnesium and aluminum oxides at elevated temperatures. Technical progress report, December 19, 1972--December 18, 1973
Nabarro- Herring creep was conclusively identified as the mechanism for the creep in oxygen of polycrystalline MgO doped with 0.53 cation % iron or less. At higher dopant levels both Nabarro-Herring creep and Coble creep contribute to creep deformation in air. An analytical procedure was developed to estimate from the creep data of polycrystalline, iron-doped MgO diffusion constants for Mg and O grain boundary diffusion and Mg lattice diffusion. The creep in air at l500 deg C of coarse-grained iron-doped, (0.53 cation %) polycrystalline MgO consists of (a) viscous, NabarroHerring creep and (b) a nonviscous dislocation process that is independent of grain size. Nabarro- Herring creep was identified in pure polycrystalline Al/sub 2/O/sub 3/. In iron-doped (1 cation %), polycrystalline Al/sub 2/O/sub 3/ both Nabarro- Herring and Coble diffusional creep processes contribute to creep deformation. (auth)
- Research Organization:
- Utah Univ., Salt Lake City (USA). Div. of Materials Science and Engineering
- NSA Number:
- NSA-29-018003
- OSTI ID:
- 4347708
- Report Number(s):
- COO--1591-24
- Country of Publication:
- United States
- Language:
- English
Similar Records
Impurity effects on the creep of polycrystalline magnesium and aluminum oxides at elevated temperatures. Final technical progress report, April 1, 1966-September 30, 1981
Impurity effects on the creep of polycrystalline magnesium and aluminum oxides at elevated temperatures. Technical progress report, December 19, 1974--December 18, 1975
Related Subjects
*MAGNESIUM OXIDES-- CREEP
DIFFUSION
DOPED MATERIALS
GRAIN BOUNDARIES
GRAIN SIZE
IMPURITIES
IRON ADDITIONS
MASS TRANSFER
N50130 -- Metals
Ceramics
& Other Materials--Ceramics & Cermets--Properties
Structure & Phase Studies
N80730* --General & Miscellaneous--Materials
POLYCRYSTALS
STRESSES