SOME CREEP PROPERTIES OF ZIRCALOY-2

Technical Report · Thu Jun 01 04:00:00 EDT 1961

OSTI ID:4837457

Bell, L G

The strain-age-hardening processes that occur in Zircaloy-2 in creep were studied, particularly their effect on the creep strength. The creep strength of annealed and cold-worked Zircaloy-2 was found to be much the same as that observed by other workers, and there is no indication that the material is unsafe up to conditions of 20,000 psi at 300 deg C for the annealed and 24,000 psi at 300 deg C for the 13.1% cold-worked alloy. There is a rapid decrease in creep strength above 300 deg C for both materials, and this is probably their most serious limitation. Jogs which occasionally appear in creep curves for Zircaloy-2 at low stress contribute a small amount to the strain, but once they are over, the material exhibits normal creep behavior. During the early stages of creep, annealed Zircaloy-2 has an unexpectedly high creep resistance at temperatures between 250 deg and 400 deg C. This is thought to be caused by a pre-load strengthening. At temperatures below 250 deg C primary deformation is high because the strengthening mechanism does not operate. Zircaloy-2 undergoes three strain-age-hardening reactors. Strengthening of the material by cold work allows time for the reactions to occur and results in a much higher creep resistance during the early stages of creep. In cold-worked Zircaloy-2 at 300 deg C when the creep stresses are above 40,000 psi, there is a marked decrease in the strain at which tertiary creep begins and also a loss of ductility. Enlarging the grain size of annealed Zircaloy-2 changes the shape of the curve, increasing primary strain, but it does not impair the creep strength. (auth)

• Research Organization: Atomic Energy of Canada Ltd., Chalk River, Ont.
• NSA Number: NSA-15-031174
• OSTI ID: 4837457
• Report Number(s): CRGM-1017; AECL-1305
• Country of Publication: Canada
• Language: English

Related Subjects

ANNEALING
COLD WORKING
CREEP
DEFORMATION
DIAGRAMS
DUCTILITY
GRAIN SIZE
HEAT TREATMENTS
LOSSES
METALS, CERAMICS, AND OTHER MATERIALS
PRESSURE
QUANTITY RATIO
REACTION KINETICS
REACTORS
SAFETY
STABILITY
STRESSES
TEMPERATURE
TEMPERING
TENSILE PROPERTIES
ZIRCALOY