Application of a model for strain aging under stress to niobium
A simple model is proposed to rationalize yield point return curves obtained when specimens of a b.c.c. metal-interstitial atom solid solution are strain aged under stress. Several basic assumptions are involved. First that the solute is mobile enough to diffuse to the dislocations and strain age them during the period that they wait in front of obstacles to their motion for thermal activation (Sleeswyk's hypothesis). Second, the solute is not mobile enough to be dragged with the dislocations as they advance between obstacles. Third, the stress increment due to the strain aging of the dislocations is additive to the stress of the basic rate controlling mechanism. Fourth, in agreement with experimental observations, the strain again follows conventional static strain aging kinetics involving both Shoeck-Seeger (Snoek) reordering of the solute in the stress fields of the dislocations and the long range Cottrell-Bilby drift of the solute to form dislocation atmospheres. Tests of the model using niobium-oxygen data taken from the literature demonstrate that it is able to account, for the effects of both temperature and prestrain on the strain aging under stress kinetics curves.
- Research Organization:
- Department of Materials Science and Engineering, University of Florida, Gainesville, FL
- OSTI ID:
- 6141149
- Journal Information:
- Acta Metall.; (United States), Journal Name: Acta Metall.; (United States) Vol. 31:10; ISSN AMETA
- Country of Publication:
- United States
- Language:
- English
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STRAIN AGING OF REFRACTORY METALS
Related Subjects
360103* -- Metals & Alloys-- Mechanical Properties
AGING
BCC LATTICES
CRYSTAL DEFECTS
CRYSTAL LATTICES
CRYSTAL STRUCTURE
CRYSTALS
CUBIC LATTICES
DATA
DESTRUCTIVE TESTING
DISLOCATIONS
ELEMENTS
EXPERIMENTAL DATA
INFORMATION
INTERSTITIALS
KINETICS
LINE DEFECTS
MATERIALS TESTING
MATHEMATICAL MODELS
METALS
NIOBIUM
NONMETALS
NUMERICAL DATA
OXYGEN
POINT DEFECTS
STRAIN AGING
STRESS ANALYSIS
STRESSES
TESTING
TRANSITION ELEMENTS