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U.S. Department of Energy
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DELAYED FAILURE HYDROGEN EMBRITTLEMENT OF ZIRCONIUM. Summary Report, September 15, 1961 to September 14, 1962

Technical Report ·
DOI:https://doi.org/10.2172/4794705· OSTI ID:4794705

The extent to which zirconium and zirconium alloys exhibit delayed failure (static fatigue) as caused by a combination of absorbed hydrogen and applied stress was investigated. Susceptibility to time-dependent fracture was evaluated for unalloyed zirconium and Zircaloy-2 with 200 and 500 ppm hydrogen as well as for an experimental Zr Al-Sn-Mo alloy and the Canadian Zr-2.5Nb cladding material. For unalloyed zirconium and Zircaloy-2 containing up to 500 ppm hydrogen, no room-temperature, timedependent fracture occurred which could be definitely attributed to the delayed failure phenomenon; an increased grain size, 20% cold deformation by rolling, or corrosion in 750 deg F steam did not significantly affect this behavior. The curve of applied stress versus time to failure at room temperature for the high-strength Zr-Al-Sn--Mo alloy containing 500 ppm hydrcgen established a strong susceptibility to delayed failure due to hydrogen absorption; studies on vacuum-annealed material showed no failures. Further, reduced temperature indicated that the occurrence of static fatigue is temperature dependent. Data for heattreated Zr 2.5Nb containing 500 ppm hydrogen indicated that this material is moderately sensitive to delayed failure at room temperature; higher hydrogen contents caused a greatly increased susceptibility to time-dependent fracture. (auth)

Research Organization:
Illinois Inst. of Tech., Chicago. Armour Research Foundation
NSA Number:
NSA-17-000526
OSTI ID:
4794705
Report Number(s):
ARF-2230-12
Country of Publication:
United States
Language:
English