CREEP OF ALUMINUM-LITHIUM ALLOY
The tensile creep properties of an aluminum- 12 atom% (3.4 wt%) lithium alloy were measured in the temperature range of l50 to 250 deg C and at stresses of 3300, 5800, and 8500 psi. The second-stage creep rate of the alloy had an activation energy of 3l.5 kilocalories per mole and varied with stress raised to the 3.5 power. The creep properties were affected very little by the shape, size, and distribution of the second-phase particles, but were strongly dependent on the grain structure of the matrix. A new metallurgical phenomenon, termed strain-induced diffusion,'' was ob served, in which lithium diffused to grain boundaries that were oriented normal to the stress and precipitated as continuous, second-phase layers. The appearance and location of the layers suggested that stress concentrations were relievcd by the formation of the low- density second phase in preference to the formation of voids or cracks. (auth)
- Research Organization:
- Du Pont de Nemours (E.I.) & Co. Savannah River Lab., Aiken, S.C.
- DOE Contract Number:
- AT(07-2)-1
- NSA Number:
- NSA-16-010523
- OSTI ID:
- 4792719
- Report Number(s):
- DP-622
- Resource Relation:
- Other Information: Orig. Receipt Date: 31-DEC-62
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
ACTIVATION ENERGY
ALUMINUM ALLOYS
CONFIGURATION
CRACKS
CREEP
DEFECTS
DEFORMATION
DIFFUSION
DISTRIBUTION
GRAIN BOUNDARIES
GRAIN SIZE
LATTICES
LAYERS
LITHIUM
LITHIUM ALLOYS
MEASURED VALUES
PHASE DIAGRAMS
POROSITY
PRECIPITATION
PRESSURE
QUALITATIVE ANALYSIS
STRESSES
TEMPERATURE
TENSILE PROPERTIES
THERMODYNAMICS