Plastic deformation in nonstoichiometric UO/sub 2+x/ single crystals - II. Deformation at high temperatures

Journal Article · Fri Apr 01 04:00:00 EST 1988 · Acta Metall.; (United States)

DOI:https://doi.org/10.1016/0001-6160(88)90161-7· OSTI ID:7128102

Keller, R J; Mitchell, T E; Heuer, A H

Single crystals of UO/sub 2+x/ (5 x 10/sup -6/ less than or equal to chi less than or equal to 10/sup -4/) have been deformed in equilibrium CO/CO/sub 2/ mixtures at 1073, 1273 and 1673 K in compression. The primary glide plane is dependent on orientation, temperature and extent of non-stoichiometry, such that (001)<110> glide is most common at low O/U ratios and high temperatures, while (111)<110> glide is prevalent at high O/U ratios and low temperatures. The critical resolved shear stress (CRSS) for (001) glide is nearly independent of chi, while the CRSS for (111) glide decreases with increasing chi. At low values of chi, slip is controlled by interactions between dislocations and extrinsic defects the dislocation and defect mobilities are nearly equal (for the strain rates examined) at temperatures between 1350 and 1650 K. At high values of chi, the interactions between dislocations and extrinsic defects still play a major role in controlling dislocation motion; however, it appears that the presence of oxygen interstitial defect clusters serves to diminish the hardening effects of impurities for (111) glide. When deformed specimens with high values of chi are reduced to low values of chi, dislocations act as sinks for ''exsolved'' oxygen, resulting in increase in strength on further deformation.

• Research Organization: Precision Castparts Corp., Cleveland, OH (US)
• OSTI ID: 7128102
• Journal Information: Acta Metall.; (United States), Journal Name: Acta Metall.; (United States) Vol. 36:4; ISSN AMETA
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
360103* -- Metals &amp; Alloys-- Mechanical Properties
37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY
38 RADIATION CHEMISTRY, RADIOCHEMISTRY, AND NUCLEAR CHEMISTRY
400702 -- Radiochemistry &amp; Nuclear Chemistry-- Properties of Radioactive Materials
400800 -- Combustion
Pyrolysis
&amp; High-Temperature Chemistry
ACTINIDE COMPOUNDS
CARBON COMPOUNDS
CARBON DIOXIDE
CARBON MONOXIDE
CARBON OXIDES
CHALCOGENIDES
CHEMICAL REACTION KINETICS
CRYSTALS
DEFORMATION
ELEMENTS
HIGH TEMPERATURE
IMPURITIES
KINETICS
MECHANICAL PROPERTIES
NONMETALS
OXIDES
OXYGEN
OXYGEN COMPOUNDS
PLASTICITY
REACTION KINETICS
SHEAR
STOICHIOMETRY
URANIUM COMPOUNDS
URANIUM OXIDES