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Effect of dynamically charged helium on mechanical properties of V-4Cr-4Ti

Technical Report ·
OSTI ID:47746
V-4Cr-4Ti has been reported to be virtually immune to irradiation embrittlement under conditions of negligible helium generation; DBTTs determined from one-third-size Charpy-impact specimens irradiated in a non-DHCE experiment were <{minus}200{degrees}C. The effects of dynamically charged helium and tritium, and of neutron damage, on DBTT of the alloy were determined after irradiation in the Dynamic Helium Charging Experiment (DHCE). TEM disks irradiated to 18-31 dpa at 425-600{degrees}C were fractured by repeated bending in a low-temperature bath. Miniature specimens were used because no Charpy-impact specimens were included in the DHCE experiment. Ductile-brittle transition behavior was determined from quantitative SEM fractography. Brittle fracture surface morphology was not observed at >{minus}120{degrees}C regardless of the level of dpa damage or helium and tritium content in the alloy. Predominantly brittle-cleavage fracture morphologies were observed only at {minus}196{degrees}C in some specimens irradiated to 31 dpa at 425{degrees}C and in which the estimated helium and tritium contents were highest. This indicates a DBTT between {minus}175 and {minus}200{degrees}C in specimens containing the highest levels of dpa damage, helium, and tritium in the DHCE experiment. No intergranular fracture was observed.
Research Organization:
Oak Ridge National Lab., TN (United States)
DOE Contract Number:
W-31109-ENG-38
OSTI ID:
47746
Report Number(s):
DOE/ER--0313/16; ON: DE95003404
Country of Publication:
United States
Language:
English