Estimated creep properties of Zircaloy during neutron irradiation (LWBR Development Program)

Technical Report · Wed May 01 04:00:00 EDT 1968

OSTI ID:7094967

Nichols, F A

A comprehensive model is proposed to explain the creep of Zircaloy during neutron irradiation. The in-pile softening observed at low stresses is hypothesized to be due to the growth-directed Roberts-Cottrell yielding creep originally proposed for ..cap alpha..-uranium, or the formation of point defect loops preferentially on certain planes in response to the applied stress, (which may or may not be followed by yielding creep), or to a combination of these two mechanisms. The in-pile hardening observed at high stresses (or strain-rates) is proposed to be due to the cutting by dislocations of depleted zones as originally proposed to account for post-irradiation hardening. In this stress (strain-rate) region, in-pile behavior is identical to post-irradiation behavior. At intermediate stresses (strain-rates) a mechanism of radiation-enhanced climb around depleted zones is suggested as being rate-controlling. As the stress is decreased, the climb process becomes easier and the rate is then controlled by glide at a flow stress characteristic of unirradiated, annealed material, it being proposed that radiation-enhanced diffusion enables climbing around the normal strain-hardening obstacles. At still lower stresses, this glide process becomes negligibly slow compared with the growth connected creep mechanism which is presumed to operate independently. The overall scheme is shown to be in good agreement with all the in-pile data presently available. (NSA 22: 36512)

• Research Organization: Bettis Atomic Power Lab., Pittsburgh, PA (USA)
• DOE Contract Number: AT(11-1)-GEN-14
• OSTI ID: 7094967
• Report Number(s): WAPD-TM-756
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
360106* -- Metals & Alloys-- Radiation Effects
ALLOYS
BREEDER REACTORS
CREEP
LWBR TYPE REACTORS
MATHEMATICAL MODELS
MECHANICAL PROPERTIES
PHYSICAL RADIATION EFFECTS
RADIATION EFFECTS
REACTORS
THERMAL REACTORS
TIN ALLOYS
WATER COOLED REACTORS
WATER MODERATED REACTORS
ZIRCALOY
ZIRCONIUM ALLOYS
ZIRCONIUM BASE ALLOYS