Irradiation assisted stress corrosion cracking of HTH Alloy X-750 and Alloy 625
In-reactor testing of bolt-loaded precracked compact tension specimens was performed in 360{degree}C water to determine effect of irradiation on the SCC behavior of HTH Alloy X-750 and direct aged Alloy 625. Out-of-flux and autoclave control specimens provided baseline data. Primary test variables were stress intensity factor, fluence, chemistry, processing history, prestrain. Results for the first series of experiments were presented at a previous conference. Data from two more recent experiments are compared with previous results; they confirm that high irradiation levels significantly reduce SCC resistance in HTH Alloy X-750. Heat-to-heat differences in IASCC were related to differences in boron content, with low boron heats showing improved SCC resistance. The in-reactor SCC performance of Alloy 625 was superior to that for Alloy X-750, as no cracking was observed in any Alloy 625 specimens even though they were tested at very high K{sub 1} and fluence levels. A preliminary SCC usage model developed for Alloy X-750 indicates that in-reactor creep processes, which relax stresses but also increase crack tip strain rates, and radiolysis effects accelerate SCC. Hence, in-reactor SCC damage under high flux conditions may be more severe than that associated with postirradiation tests. In addition, preliminary mechanism studies were performed to determine the cause of IASCC In Alloy X-750.
- Research Organization:
- Westinghouse Electric Corp., West Mifflin, PA (United States). Bettis Atomic Power Lab.; Bettis Atomic Power Lab., Pittsburgh, PA (United States)
- Sponsoring Organization:
- USDOE, Washington, DC (United States)
- DOE Contract Number:
- AC11-93PN38195; AC11-89PN38014
- OSTI ID:
- 10154569
- Report Number(s):
- WAPD-T-3034; CONF-9403119-1; ON: DE94012667; TRN: 94:012076
- Resource Relation:
- Conference: 1994 meeting of the International Collaborative Group on Irradiation-Assisted Stress Corrosion Cracking (ICGIASCC),Stevenson, WA (United States),30 Mar - 1 Apr 1994; Other Information: PBD: [1994]
- Country of Publication:
- United States
- Language:
- English
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Irradiation-assisted stress corrosion cracking in HTH Alloy X-750 and Alloy 625
Irradiation-assisted stress corrosion cracking of HTH Alloy X-750 and Alloy 625